diff --git a/ChangeLog b/ChangeLog
index f1b5453..192dd25 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2010-01-14: Version 2.0.6
+
+        Added ES5 Object.getPrototypeOf, GetOwnPropertyDescriptor,
+        GetOwnProperty, FromPropertyDescriptor.
+
+        Fixed Mac x64 build errors.
+
+        Improved performance of some math and string operations.
+
+        Improved performance of some regexp operations.
+
+        Improved performance of context creation.
+
+        Improved performance of hash tables.
+
+
 2009-12-18: Version 2.0.5
 
         Extended to upper limit of map space to allow for 7 times as many map
diff --git a/SConstruct b/SConstruct
index ef0917f..9718907 100644
--- a/SConstruct
+++ b/SConstruct
@@ -949,6 +949,7 @@
 
   d8_env = Environment()
   d8_env.Replace(**context.flags['d8'])
+  context.ApplyEnvOverrides(d8_env)
   shell = d8_env.Program('d8' + suffix, object_files + shell_files)
   context.d8_targets.append(shell)
 
diff --git a/include/v8-debug.h b/include/v8-debug.h
index b27bacc..10b41e2 100644
--- a/include/v8-debug.h
+++ b/include/v8-debug.h
@@ -258,8 +258,11 @@
   * supplied TCP/IP port for remote debugger connection.
   * \param name the name of the embedding application
   * \param port the TCP/IP port to listen on
+  * \param wait_for_connection whether V8 should pause on a first statement
+  *   allowing remote debugger to connect before anything interesting happened
   */
-  static bool EnableAgent(const char* name, int port);
+  static bool EnableAgent(const char* name, int port,
+                          bool wait_for_connection = false);
 };
 
 
diff --git a/include/v8.h b/include/v8.h
index 2e30992..6125286 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -503,6 +503,7 @@
 
   virtual int Length() = 0;
   virtual unsigned* Data() = 0;
+  virtual bool HasError() = 0;
 };
 
 
diff --git a/src/api.cc b/src/api.cc
index d793b9f..ab5d0a5 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -3741,8 +3741,8 @@
 }
 
 
-bool Debug::EnableAgent(const char* name, int port) {
-  return i::Debugger::StartAgent(name, port);
+bool Debug::EnableAgent(const char* name, int port, bool wait_for_connection) {
+  return i::Debugger::StartAgent(name, port, wait_for_connection);
 }
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
diff --git a/src/arm/assembler-arm-inl.h b/src/arm/assembler-arm-inl.h
index 5f47cb7..fd2fcd3 100644
--- a/src/arm/assembler-arm-inl.h
+++ b/src/arm/assembler-arm-inl.h
@@ -229,14 +229,24 @@
 
 
 Address Assembler::target_address_address_at(Address pc) {
-  Instr instr = Memory::int32_at(pc);
-  // Verify that the instruction at pc is a ldr<cond> <Rd>, [pc +/- offset_12].
+  Address target_pc = pc;
+  Instr instr = Memory::int32_at(target_pc);
+  // If we have a bx instruction, the instruction before the bx is
+  // what we need to patch.
+  static const int32_t kBxInstMask = 0x0ffffff0;
+  static const int32_t kBxInstPattern = 0x012fff10;
+  if ((instr & kBxInstMask) == kBxInstPattern) {
+    target_pc -= kInstrSize;
+    instr = Memory::int32_at(target_pc);
+  }
+  // Verify that the instruction to patch is a
+  // ldr<cond> <Rd>, [pc +/- offset_12].
   ASSERT((instr & 0x0f7f0000) == 0x051f0000);
   int offset = instr & 0xfff;  // offset_12 is unsigned
   if ((instr & (1 << 23)) == 0) offset = -offset;  // U bit defines offset sign
   // Verify that the constant pool comes after the instruction referencing it.
   ASSERT(offset >= -4);
-  return pc + offset + 8;
+  return target_pc + offset + 8;
 }
 
 
diff --git a/src/arm/codegen-arm-inl.h b/src/arm/codegen-arm-inl.h
index 749f32d..17e18d9 100644
--- a/src/arm/codegen-arm-inl.h
+++ b/src/arm/codegen-arm-inl.h
@@ -67,16 +67,6 @@
 void DeferredCode::Jump() { __ jmp(&entry_label_); }
 void DeferredCode::Branch(Condition cc) { __ b(cc, &entry_label_); }
 
-void CodeGenerator::GenerateMathSin(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(SIN, args);
-}
-
-
-void CodeGenerator::GenerateMathCos(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(COS, args);
-}
-
-
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/arm/codegen-arm.cc b/src/arm/codegen-arm.cc
index 89d974c..70d8ab4 100644
--- a/src/arm/codegen-arm.cc
+++ b/src/arm/codegen-arm.cc
@@ -44,7 +44,8 @@
 
 static void EmitIdenticalObjectComparison(MacroAssembler* masm,
                                           Label* slow,
-                                          Condition cc);
+                                          Condition cc,
+                                          bool never_nan_nan);
 static void EmitSmiNonsmiComparison(MacroAssembler* masm,
                                     Label* rhs_not_nan,
                                     Label* slow,
@@ -186,12 +187,18 @@
     function_return_is_shadowed_ = false;
 
     VirtualFrame::SpilledScope spilled_scope;
-    if (scope_->num_heap_slots() > 0) {
+    int heap_slots = scope_->num_heap_slots();
+    if (heap_slots > 0) {
       // Allocate local context.
       // Get outer context and create a new context based on it.
       __ ldr(r0, frame_->Function());
       frame_->EmitPush(r0);
-      frame_->CallRuntime(Runtime::kNewContext, 1);  // r0 holds the result
+      if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+        FastNewContextStub stub(heap_slots);
+        frame_->CallStub(&stub, 1);
+      } else {
+        frame_->CallRuntime(Runtime::kNewContext, 1);
+      }
 
 #ifdef DEBUG
       JumpTarget verified_true;
@@ -240,28 +247,35 @@
     // initialization because the arguments object may be stored in the
     // context.
     if (scope_->arguments() != NULL) {
-      ASSERT(scope_->arguments_shadow() != NULL);
       Comment cmnt(masm_, "[ allocate arguments object");
-      { Reference shadow_ref(this, scope_->arguments_shadow());
-        { Reference arguments_ref(this, scope_->arguments());
-          ArgumentsAccessStub stub(ArgumentsAccessStub::NEW_OBJECT);
-          __ ldr(r2, frame_->Function());
-          // The receiver is below the arguments, the return address,
-          // and the frame pointer on the stack.
-          const int kReceiverDisplacement = 2 + scope_->num_parameters();
-          __ add(r1, fp, Operand(kReceiverDisplacement * kPointerSize));
-          __ mov(r0, Operand(Smi::FromInt(scope_->num_parameters())));
-          frame_->Adjust(3);
-          __ stm(db_w, sp, r0.bit() | r1.bit() | r2.bit());
-          frame_->CallStub(&stub, 3);
-          frame_->EmitPush(r0);
-          arguments_ref.SetValue(NOT_CONST_INIT);
-        }
-        shadow_ref.SetValue(NOT_CONST_INIT);
-      }
+      ASSERT(scope_->arguments_shadow() != NULL);
+      Variable* arguments = scope_->arguments()->var();
+      Variable* shadow = scope_->arguments_shadow()->var();
+      ASSERT(arguments != NULL && arguments->slot() != NULL);
+      ASSERT(shadow != NULL && shadow->slot() != NULL);
+      ArgumentsAccessStub stub(ArgumentsAccessStub::NEW_OBJECT);
+      __ ldr(r2, frame_->Function());
+      // The receiver is below the arguments, the return address, and the
+      // frame pointer on the stack.
+      const int kReceiverDisplacement = 2 + scope_->num_parameters();
+      __ add(r1, fp, Operand(kReceiverDisplacement * kPointerSize));
+      __ mov(r0, Operand(Smi::FromInt(scope_->num_parameters())));
+      frame_->Adjust(3);
+      __ stm(db_w, sp, r0.bit() | r1.bit() | r2.bit());
+      frame_->CallStub(&stub, 3);
+      frame_->EmitPush(r0);
+      StoreToSlot(arguments->slot(), NOT_CONST_INIT);
+      StoreToSlot(shadow->slot(), NOT_CONST_INIT);
       frame_->Drop();  // Value is no longer needed.
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      __ mov(ip, Operand(Factory::the_hole_value()));
+      frame_->EmitPush(ip);
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.
@@ -613,15 +627,7 @@
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     LoadAndSpill(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       LoadAndSpill(property->key());
@@ -1986,13 +1992,9 @@
   frame_->EmitPush(r0);
 
   // Store the caught exception in the catch variable.
-  { Reference ref(this, node->catch_var());
-    ASSERT(ref.is_slot());
-    // Here we make use of the convenient property that it doesn't matter
-    // whether a value is immediately on top of or underneath a zero-sized
-    // reference.
-    ref.SetValue(NOT_CONST_INIT);
-  }
+  Variable* catch_var = node->catch_var()->var();
+  ASSERT(catch_var != NULL && catch_var->slot() != NULL);
+  StoreToSlot(catch_var->slot(), NOT_CONST_INIT);
 
   // Remove the exception from the stack.
   frame_->Drop();
@@ -2298,12 +2300,21 @@
   VirtualFrame::SpilledScope spilled_scope;
   ASSERT(boilerplate->IsBoilerplate());
 
-  // Create a new closure.
-  frame_->EmitPush(cp);
   __ mov(r0, Operand(boilerplate));
-  frame_->EmitPush(r0);
-  frame_->CallRuntime(Runtime::kNewClosure, 2);
-  frame_->EmitPush(r0);
+  // Use the fast case closure allocation code that allocates in new
+  // space for nested functions that don't need literals cloning.
+  if (scope()->is_function_scope() && boilerplate->NumberOfLiterals() == 0) {
+    FastNewClosureStub stub;
+    frame_->EmitPush(r0);
+    frame_->CallStub(&stub, 1);
+    frame_->EmitPush(r0);
+  } else {
+    // Create a new closure.
+    frame_->EmitPush(cp);
+    frame_->EmitPush(r0);
+    frame_->CallRuntime(Runtime::kNewClosure, 2);
+    frame_->EmitPush(r0);
+  }
 }
 
 
@@ -2444,6 +2455,87 @@
 }
 
 
+void CodeGenerator::StoreToSlot(Slot* slot, InitState init_state) {
+  ASSERT(slot != NULL);
+  if (slot->type() == Slot::LOOKUP) {
+    ASSERT(slot->var()->is_dynamic());
+
+    // For now, just do a runtime call.
+    frame_->EmitPush(cp);
+    __ mov(r0, Operand(slot->var()->name()));
+    frame_->EmitPush(r0);
+
+    if (init_state == CONST_INIT) {
+      // Same as the case for a normal store, but ignores attribute
+      // (e.g. READ_ONLY) of context slot so that we can initialize
+      // const properties (introduced via eval("const foo = (some
+      // expr);")). Also, uses the current function context instead of
+      // the top context.
+      //
+      // Note that we must declare the foo upon entry of eval(), via a
+      // context slot declaration, but we cannot initialize it at the
+      // same time, because the const declaration may be at the end of
+      // the eval code (sigh...) and the const variable may have been
+      // used before (where its value is 'undefined'). Thus, we can only
+      // do the initialization when we actually encounter the expression
+      // and when the expression operands are defined and valid, and
+      // thus we need the split into 2 operations: declaration of the
+      // context slot followed by initialization.
+      frame_->CallRuntime(Runtime::kInitializeConstContextSlot, 3);
+    } else {
+      frame_->CallRuntime(Runtime::kStoreContextSlot, 3);
+    }
+    // Storing a variable must keep the (new) value on the expression
+    // stack. This is necessary for compiling assignment expressions.
+    frame_->EmitPush(r0);
+
+  } else {
+    ASSERT(!slot->var()->is_dynamic());
+
+    JumpTarget exit;
+    if (init_state == CONST_INIT) {
+      ASSERT(slot->var()->mode() == Variable::CONST);
+      // Only the first const initialization must be executed (the slot
+      // still contains 'the hole' value). When the assignment is
+      // executed, the code is identical to a normal store (see below).
+      Comment cmnt(masm_, "[ Init const");
+      __ ldr(r2, SlotOperand(slot, r2));
+      __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
+      __ cmp(r2, ip);
+      exit.Branch(ne);
+    }
+
+    // We must execute the store.  Storing a variable must keep the
+    // (new) value on the stack. This is necessary for compiling
+    // assignment expressions.
+    //
+    // Note: We will reach here even with slot->var()->mode() ==
+    // Variable::CONST because of const declarations which will
+    // initialize consts to 'the hole' value and by doing so, end up
+    // calling this code.  r2 may be loaded with context; used below in
+    // RecordWrite.
+    frame_->EmitPop(r0);
+    __ str(r0, SlotOperand(slot, r2));
+    frame_->EmitPush(r0);
+    if (slot->type() == Slot::CONTEXT) {
+      // Skip write barrier if the written value is a smi.
+      __ tst(r0, Operand(kSmiTagMask));
+      exit.Branch(eq);
+      // r2 is loaded with context when calling SlotOperand above.
+      int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
+      __ mov(r3, Operand(offset));
+      __ RecordWrite(r2, r3, r1);
+    }
+    // If we definitely did not jump over the assignment, we do not need
+    // to bind the exit label.  Doing so can defeat peephole
+    // optimization.
+    if (init_state == CONST_INIT || slot->type() == Slot::CONTEXT) {
+      exit.Bind();
+    }
+  }
+}
+
+
 void CodeGenerator::LoadFromGlobalSlotCheckExtensions(Slot* slot,
                                                       TypeofState typeof_state,
                                                       Register tmp,
@@ -2601,42 +2693,6 @@
 }
 
 
-// This deferred code stub will be used for creating the boilerplate
-// by calling Runtime_CreateObjectLiteralBoilerplate.
-// Each created boilerplate is stored in the JSFunction and they are
-// therefore context dependent.
-class DeferredObjectLiteral: public DeferredCode {
- public:
-  explicit DeferredObjectLiteral(ObjectLiteral* node) : node_(node) {
-    set_comment("[ DeferredObjectLiteral");
-  }
-
-  virtual void Generate();
-
- private:
-  ObjectLiteral* node_;
-};
-
-
-void DeferredObjectLiteral::Generate() {
-  // Argument is passed in r1.
-
-  // If the entry is undefined we call the runtime system to compute
-  // the literal.
-  // Literal array (0).
-  __ push(r1);
-  // Literal index (1).
-  __ mov(r0, Operand(Smi::FromInt(node_->literal_index())));
-  __ push(r0);
-  // Constant properties (2).
-  __ mov(r0, Operand(node_->constant_properties()));
-  __ push(r0);
-  __ CallRuntime(Runtime::kCreateObjectLiteralBoilerplate, 3);
-  __ mov(r2, Operand(r0));
-  // Result is returned in r2.
-}
-
-
 void CodeGenerator::VisitObjectLiteral(ObjectLiteral* node) {
 #ifdef DEBUG
   int original_height = frame_->height();
@@ -2644,39 +2700,22 @@
   VirtualFrame::SpilledScope spilled_scope;
   Comment cmnt(masm_, "[ ObjectLiteral");
 
-  DeferredObjectLiteral* deferred = new DeferredObjectLiteral(node);
-
-  // Retrieve the literal array and check the allocated entry.
-
   // Load the function of this activation.
-  __ ldr(r1, frame_->Function());
-
-  // Load the literals array of the function.
-  __ ldr(r1, FieldMemOperand(r1, JSFunction::kLiteralsOffset));
-
-  // Load the literal at the ast saved index.
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ ldr(r2, FieldMemOperand(r1, literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code.
-  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
-  __ cmp(r2, Operand(ip));
-  deferred->Branch(eq);
-  deferred->BindExit();
-
-  // Push the object literal boilerplate.
-  frame_->EmitPush(r2);
-
-  // Clone the boilerplate object.
-  Runtime::FunctionId clone_function_id = Runtime::kCloneLiteralBoilerplate;
-  if (node->depth() == 1) {
-    clone_function_id = Runtime::kCloneShallowLiteralBoilerplate;
+  __ ldr(r2, frame_->Function());
+  // Literal array.
+  __ ldr(r2, FieldMemOperand(r2, JSFunction::kLiteralsOffset));
+  // Literal index.
+  __ mov(r1, Operand(Smi::FromInt(node->literal_index())));
+  // Constant properties.
+  __ mov(r0, Operand(node->constant_properties()));
+  frame_->EmitPushMultiple(3, r2.bit() | r1.bit() | r0.bit());
+  if (node->depth() > 1) {
+    frame_->CallRuntime(Runtime::kCreateObjectLiteral, 3);
+  } else {
+    frame_->CallRuntime(Runtime::kCreateObjectLiteralShallow, 3);
   }
-  frame_->CallRuntime(clone_function_id, 1);
   frame_->EmitPush(r0);  // save the result
-  // r0: cloned object literal
+  // r0: created object literal
 
   for (int i = 0; i < node->properties()->length(); i++) {
     ObjectLiteral::Property* property = node->properties()->at(i);
@@ -2724,42 +2763,6 @@
 }
 
 
-// This deferred code stub will be used for creating the boilerplate
-// by calling Runtime_CreateArrayLiteralBoilerplate.
-// Each created boilerplate is stored in the JSFunction and they are
-// therefore context dependent.
-class DeferredArrayLiteral: public DeferredCode {
- public:
-  explicit DeferredArrayLiteral(ArrayLiteral* node) : node_(node) {
-    set_comment("[ DeferredArrayLiteral");
-  }
-
-  virtual void Generate();
-
- private:
-  ArrayLiteral* node_;
-};
-
-
-void DeferredArrayLiteral::Generate() {
-  // Argument is passed in r1.
-
-  // If the entry is undefined we call the runtime system to computed
-  // the literal.
-  // Literal array (0).
-  __ push(r1);
-  // Literal index (1).
-  __ mov(r0, Operand(Smi::FromInt(node_->literal_index())));
-  __ push(r0);
-  // Constant properties (2).
-  __ mov(r0, Operand(node_->literals()));
-  __ push(r0);
-  __ CallRuntime(Runtime::kCreateArrayLiteralBoilerplate, 3);
-  __ mov(r2, Operand(r0));
-  // Result is returned in r2.
-}
-
-
 void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
 #ifdef DEBUG
   int original_height = frame_->height();
@@ -2767,39 +2770,22 @@
   VirtualFrame::SpilledScope spilled_scope;
   Comment cmnt(masm_, "[ ArrayLiteral");
 
-  DeferredArrayLiteral* deferred = new DeferredArrayLiteral(node);
-
-  // Retrieve the literal array and check the allocated entry.
-
   // Load the function of this activation.
-  __ ldr(r1, frame_->Function());
-
-  // Load the literals array of the function.
-  __ ldr(r1, FieldMemOperand(r1, JSFunction::kLiteralsOffset));
-
-  // Load the literal at the ast saved index.
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ ldr(r2, FieldMemOperand(r1, literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code.
-  __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
-  __ cmp(r2, Operand(ip));
-  deferred->Branch(eq);
-  deferred->BindExit();
-
-  // Push the object literal boilerplate.
-  frame_->EmitPush(r2);
-
-  // Clone the boilerplate object.
-  Runtime::FunctionId clone_function_id = Runtime::kCloneLiteralBoilerplate;
-  if (node->depth() == 1) {
-    clone_function_id = Runtime::kCloneShallowLiteralBoilerplate;
+  __ ldr(r2, frame_->Function());
+  // Literals array.
+  __ ldr(r2, FieldMemOperand(r2, JSFunction::kLiteralsOffset));
+  // Literal index.
+  __ mov(r1, Operand(Smi::FromInt(node->literal_index())));
+  // Constant elements.
+  __ mov(r0, Operand(node->constant_elements()));
+  frame_->EmitPushMultiple(3, r2.bit() | r1.bit() | r0.bit());
+  if (node->depth() > 1) {
+    frame_->CallRuntime(Runtime::kCreateArrayLiteral, 3);
+  } else {
+    frame_->CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   }
-  frame_->CallRuntime(clone_function_id, 1);
   frame_->EmitPush(r0);  // save the result
-  // r0: cloned object literal
+  // r0: created object literal
 
   // Generate code to set the elements in the array that are not
   // literals.
@@ -2998,13 +2984,15 @@
       frame_->EmitPush(r2);
     }
 
+    // Push the receiver.
+    __ ldr(r1, frame_->Receiver());
+    frame_->EmitPush(r1);
+
     // Resolve the call.
-    frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 2);
+    frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 3);
 
     // Touch up stack with the right values for the function and the receiver.
-    __ ldr(r1, FieldMemOperand(r0, FixedArray::kHeaderSize));
-    __ str(r1, MemOperand(sp, (arg_count + 1) * kPointerSize));
-    __ ldr(r1, FieldMemOperand(r0, FixedArray::kHeaderSize + kPointerSize));
+    __ str(r0, MemOperand(sp, (arg_count + 1) * kPointerSize));
     __ str(r1, MemOperand(sp, arg_count * kPointerSize));
 
     // Call the function.
@@ -3544,21 +3532,6 @@
 }
 
 
-void CodeGenerator::GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args) {
-  VirtualFrame::SpilledScope spilled_scope;
-  LoadAndSpill(args->at(0));
-  switch (op) {
-    case SIN:
-      frame_->CallRuntime(Runtime::kMath_sin, 1);
-      break;
-    case COS:
-      frame_->CallRuntime(Runtime::kMath_cos, 1);
-      break;
-  }
-  frame_->EmitPush(r0);
-}
-
-
 void CodeGenerator::GenerateStringAdd(ZoneList<Expression*>* args) {
   ASSERT_EQ(2, args->length());
 
@@ -3570,6 +3543,42 @@
 }
 
 
+void CodeGenerator::GenerateSubString(ZoneList<Expression*>* args) {
+  ASSERT_EQ(3, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+  Load(args->at(2));
+
+  frame_->CallRuntime(Runtime::kSubString, 3);
+  frame_->EmitPush(r0);
+}
+
+
+void CodeGenerator::GenerateStringCompare(ZoneList<Expression*>* args) {
+  ASSERT_EQ(2, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+
+  frame_->CallRuntime(Runtime::kStringCompare, 2);
+  frame_->EmitPush(r0);
+}
+
+
+void CodeGenerator::GenerateRegExpExec(ZoneList<Expression*>* args) {
+  ASSERT_EQ(4, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+  Load(args->at(2));
+  Load(args->at(3));
+
+  frame_->CallRuntime(Runtime::kRegExpExec, 4);
+  frame_->EmitPush(r0);
+}
+
+
 void CodeGenerator::GenerateObjectEquals(ZoneList<Expression*>* args) {
   VirtualFrame::SpilledScope spilled_scope;
   ASSERT(args->length() == 2);
@@ -3713,7 +3722,7 @@
         bool overwrite =
             (node->expression()->AsBinaryOperation() != NULL &&
              node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
-        UnarySubStub stub(overwrite);
+        GenericUnaryOpStub stub(Token::SUB, overwrite);
         frame_->CallStub(&stub, 0);
         break;
       }
@@ -4343,83 +4352,7 @@
     case SLOT: {
       Comment cmnt(masm, "[ Store to Slot");
       Slot* slot = expression_->AsVariableProxy()->AsVariable()->slot();
-      ASSERT(slot != NULL);
-      if (slot->type() == Slot::LOOKUP) {
-        ASSERT(slot->var()->is_dynamic());
-
-        // For now, just do a runtime call.
-        frame->EmitPush(cp);
-        __ mov(r0, Operand(slot->var()->name()));
-        frame->EmitPush(r0);
-
-        if (init_state == CONST_INIT) {
-          // Same as the case for a normal store, but ignores attribute
-          // (e.g. READ_ONLY) of context slot so that we can initialize
-          // const properties (introduced via eval("const foo = (some
-          // expr);")). Also, uses the current function context instead of
-          // the top context.
-          //
-          // Note that we must declare the foo upon entry of eval(), via a
-          // context slot declaration, but we cannot initialize it at the
-          // same time, because the const declaration may be at the end of
-          // the eval code (sigh...) and the const variable may have been
-          // used before (where its value is 'undefined'). Thus, we can only
-          // do the initialization when we actually encounter the expression
-          // and when the expression operands are defined and valid, and
-          // thus we need the split into 2 operations: declaration of the
-          // context slot followed by initialization.
-          frame->CallRuntime(Runtime::kInitializeConstContextSlot, 3);
-        } else {
-          frame->CallRuntime(Runtime::kStoreContextSlot, 3);
-        }
-        // Storing a variable must keep the (new) value on the expression
-        // stack. This is necessary for compiling assignment expressions.
-        frame->EmitPush(r0);
-
-      } else {
-        ASSERT(!slot->var()->is_dynamic());
-
-        JumpTarget exit;
-        if (init_state == CONST_INIT) {
-          ASSERT(slot->var()->mode() == Variable::CONST);
-          // Only the first const initialization must be executed (the slot
-          // still contains 'the hole' value). When the assignment is
-          // executed, the code is identical to a normal store (see below).
-          Comment cmnt(masm, "[ Init const");
-          __ ldr(r2, cgen_->SlotOperand(slot, r2));
-          __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-          __ cmp(r2, ip);
-          exit.Branch(ne);
-        }
-
-        // We must execute the store.  Storing a variable must keep the
-        // (new) value on the stack. This is necessary for compiling
-        // assignment expressions.
-        //
-        // Note: We will reach here even with slot->var()->mode() ==
-        // Variable::CONST because of const declarations which will
-        // initialize consts to 'the hole' value and by doing so, end up
-        // calling this code.  r2 may be loaded with context; used below in
-        // RecordWrite.
-        frame->EmitPop(r0);
-        __ str(r0, cgen_->SlotOperand(slot, r2));
-        frame->EmitPush(r0);
-        if (slot->type() == Slot::CONTEXT) {
-          // Skip write barrier if the written value is a smi.
-          __ tst(r0, Operand(kSmiTagMask));
-          exit.Branch(eq);
-          // r2 is loaded with context when calling SlotOperand above.
-          int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
-          __ mov(r3, Operand(offset));
-          __ RecordWrite(r2, r3, r1);
-        }
-        // If we definitely did not jump over the assignment, we do not need
-        // to bind the exit label.  Doing so can defeat peephole
-        // optimization.
-        if (init_state == CONST_INIT || slot->type() == Slot::CONTEXT) {
-          exit.Bind();
-        }
-      }
+      cgen_->StoreToSlot(slot, init_state);
       break;
     }
 
@@ -4466,6 +4399,103 @@
 }
 
 
+void FastNewClosureStub::Generate(MacroAssembler* masm) {
+  // Clone the boilerplate in new space. Set the context to the
+  // current context in cp.
+  Label gc;
+
+  // Pop the boilerplate function from the stack.
+  __ pop(r3);
+
+  // Attempt to allocate new JSFunction in new space.
+  __ AllocateInNewSpace(JSFunction::kSize / kPointerSize,
+                        r0,
+                        r1,
+                        r2,
+                        &gc,
+                        TAG_OBJECT);
+
+  // Compute the function map in the current global context and set that
+  // as the map of the allocated object.
+  __ ldr(r2, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ ldr(r2, FieldMemOperand(r2, GlobalObject::kGlobalContextOffset));
+  __ ldr(r2, MemOperand(r2, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
+  __ str(r2, FieldMemOperand(r0, HeapObject::kMapOffset));
+
+  // Clone the rest of the boilerplate fields. We don't have to update
+  // the write barrier because the allocated object is in new space.
+  for (int offset = kPointerSize;
+       offset < JSFunction::kSize;
+       offset += kPointerSize) {
+    if (offset == JSFunction::kContextOffset) {
+      __ str(cp, FieldMemOperand(r0, offset));
+    } else {
+      __ ldr(r1, FieldMemOperand(r3, offset));
+      __ str(r1, FieldMemOperand(r0, offset));
+    }
+  }
+
+  // Return result. The argument boilerplate has been popped already.
+  __ Ret();
+
+  // Create a new closure through the slower runtime call.
+  __ bind(&gc);
+  __ push(cp);
+  __ push(r3);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewClosure), 2, 1);
+}
+
+
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+  // Try to allocate the context in new space.
+  Label gc;
+  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+
+  // Attempt to allocate the context in new space.
+  __ AllocateInNewSpace(length + (FixedArray::kHeaderSize / kPointerSize),
+                        r0,
+                        r1,
+                        r2,
+                        &gc,
+                        TAG_OBJECT);
+
+  // Load the function from the stack.
+  __ ldr(r3, MemOperand(sp, 0 * kPointerSize));
+
+  // Setup the object header.
+  __ LoadRoot(r2, Heap::kContextMapRootIndex);
+  __ str(r2, FieldMemOperand(r0, HeapObject::kMapOffset));
+  __ mov(r2, Operand(length));
+  __ str(r2, FieldMemOperand(r0, Array::kLengthOffset));
+
+  // Setup the fixed slots.
+  __ mov(r1, Operand(Smi::FromInt(0)));
+  __ str(r3, MemOperand(r0, Context::SlotOffset(Context::CLOSURE_INDEX)));
+  __ str(r0, MemOperand(r0, Context::SlotOffset(Context::FCONTEXT_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::PREVIOUS_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::EXTENSION_INDEX)));
+
+  // Copy the global object from the surrounding context.
+  __ ldr(r1, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::GLOBAL_INDEX)));
+
+  // Initialize the rest of the slots to undefined.
+  __ LoadRoot(r1, Heap::kUndefinedValueRootIndex);
+  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+    __ str(r1, MemOperand(r0, Context::SlotOffset(i)));
+  }
+
+  // Remove the on-stack argument and return.
+  __ mov(cp, r0);
+  __ pop();
+  __ Ret();
+
+  // Need to collect. Call into runtime system.
+  __ bind(&gc);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
+}
+
+
 // Count leading zeros in a 32 bit word.  On ARM5 and later it uses the clz
 // instruction.  On pre-ARM5 hardware this routine gives the wrong answer for 0
 // (31 instead of 32).
@@ -4692,47 +4722,55 @@
 // for "identity and not NaN".
 static void EmitIdenticalObjectComparison(MacroAssembler* masm,
                                           Label* slow,
-                                          Condition cc) {
+                                          Condition cc,
+                                          bool never_nan_nan) {
   Label not_identical;
+  Label heap_number, return_equal;
+  Register exp_mask_reg = r5;
   __ cmp(r0, Operand(r1));
   __ b(ne, &not_identical);
 
-  Register exp_mask_reg = r5;
-  __ mov(exp_mask_reg, Operand(HeapNumber::kExponentMask));
+  // The two objects are identical.  If we know that one of them isn't NaN then
+  // we now know they test equal.
+  if (cc != eq || !never_nan_nan) {
+    __ mov(exp_mask_reg, Operand(HeapNumber::kExponentMask));
 
-  // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
-  // so we do the second best thing - test it ourselves.
-  Label heap_number, return_equal;
-  // They are both equal and they are not both Smis so both of them are not
-  // Smis.  If it's not a heap number, then return equal.
-  if (cc == lt || cc == gt) {
-    __ CompareObjectType(r0, r4, r4, FIRST_JS_OBJECT_TYPE);
-    __ b(ge, slow);
-  } else {
-    __ CompareObjectType(r0, r4, r4, HEAP_NUMBER_TYPE);
-    __ b(eq, &heap_number);
-    // Comparing JS objects with <=, >= is complicated.
-    if (cc != eq) {
-      __ cmp(r4, Operand(FIRST_JS_OBJECT_TYPE));
+    // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
+    // so we do the second best thing - test it ourselves.
+    // They are both equal and they are not both Smis so both of them are not
+    // Smis.  If it's not a heap number, then return equal.
+    if (cc == lt || cc == gt) {
+      __ CompareObjectType(r0, r4, r4, FIRST_JS_OBJECT_TYPE);
       __ b(ge, slow);
-      // Normally here we fall through to return_equal, but undefined is
-      // special: (undefined == undefined) == true, but (undefined <= undefined)
-      // == false!  See ECMAScript 11.8.5.
-      if (cc == le || cc == ge) {
-        __ cmp(r4, Operand(ODDBALL_TYPE));
-        __ b(ne, &return_equal);
-        __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
-        __ cmp(r0, Operand(r2));
-        __ b(ne, &return_equal);
-        if (cc == le) {
-          __ mov(r0, Operand(GREATER));  // undefined <= undefined should fail.
-        } else  {
-          __ mov(r0, Operand(LESS));     // undefined >= undefined should fail.
+    } else {
+      __ CompareObjectType(r0, r4, r4, HEAP_NUMBER_TYPE);
+      __ b(eq, &heap_number);
+      // Comparing JS objects with <=, >= is complicated.
+      if (cc != eq) {
+        __ cmp(r4, Operand(FIRST_JS_OBJECT_TYPE));
+        __ b(ge, slow);
+        // Normally here we fall through to return_equal, but undefined is
+        // special: (undefined == undefined) == true, but
+        // (undefined <= undefined) == false!  See ECMAScript 11.8.5.
+        if (cc == le || cc == ge) {
+          __ cmp(r4, Operand(ODDBALL_TYPE));
+          __ b(ne, &return_equal);
+          __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
+          __ cmp(r0, Operand(r2));
+          __ b(ne, &return_equal);
+          if (cc == le) {
+            // undefined <= undefined should fail.
+            __ mov(r0, Operand(GREATER));
+          } else  {
+            // undefined >= undefined should fail.
+            __ mov(r0, Operand(LESS));
+          }
+          __ mov(pc, Operand(lr));       // Return.
         }
-        __ mov(pc, Operand(lr));       // Return.
       }
     }
   }
+
   __ bind(&return_equal);
   if (cc == lt) {
     __ mov(r0, Operand(GREATER));  // Things aren't less than themselves.
@@ -4743,43 +4781,45 @@
   }
   __ mov(pc, Operand(lr));  // Return.
 
-  // For less and greater we don't have to check for NaN since the result of
-  // x < x is false regardless.  For the others here is some code to check
-  // for NaN.
-  if (cc != lt && cc != gt) {
-    __ bind(&heap_number);
-    // It is a heap number, so return non-equal if it's NaN and equal if it's
-    // not NaN.
-    // The representation of NaN values has all exponent bits (52..62) set,
-    // and not all mantissa bits (0..51) clear.
-    // Read top bits of double representation (second word of value).
-    __ ldr(r2, FieldMemOperand(r0, HeapNumber::kExponentOffset));
-    // Test that exponent bits are all set.
-    __ and_(r3, r2, Operand(exp_mask_reg));
-    __ cmp(r3, Operand(exp_mask_reg));
-    __ b(ne, &return_equal);
+  if (cc != eq || !never_nan_nan) {
+    // For less and greater we don't have to check for NaN since the result of
+    // x < x is false regardless.  For the others here is some code to check
+    // for NaN.
+    if (cc != lt && cc != gt) {
+      __ bind(&heap_number);
+      // It is a heap number, so return non-equal if it's NaN and equal if it's
+      // not NaN.
+      // The representation of NaN values has all exponent bits (52..62) set,
+      // and not all mantissa bits (0..51) clear.
+      // Read top bits of double representation (second word of value).
+      __ ldr(r2, FieldMemOperand(r0, HeapNumber::kExponentOffset));
+      // Test that exponent bits are all set.
+      __ and_(r3, r2, Operand(exp_mask_reg));
+      __ cmp(r3, Operand(exp_mask_reg));
+      __ b(ne, &return_equal);
 
-    // Shift out flag and all exponent bits, retaining only mantissa.
-    __ mov(r2, Operand(r2, LSL, HeapNumber::kNonMantissaBitsInTopWord));
-    // Or with all low-bits of mantissa.
-    __ ldr(r3, FieldMemOperand(r0, HeapNumber::kMantissaOffset));
-    __ orr(r0, r3, Operand(r2), SetCC);
-    // For equal we already have the right value in r0:  Return zero (equal)
-    // if all bits in mantissa are zero (it's an Infinity) and non-zero if not
-    // (it's a NaN).  For <= and >= we need to load r0 with the failing value
-    // if it's a NaN.
-    if (cc != eq) {
-      // All-zero means Infinity means equal.
-      __ mov(pc, Operand(lr), LeaveCC, eq);  // Return equal
-      if (cc == le) {
-        __ mov(r0, Operand(GREATER));  // NaN <= NaN should fail.
-      } else {
-        __ mov(r0, Operand(LESS));     // NaN >= NaN should fail.
+      // Shift out flag and all exponent bits, retaining only mantissa.
+      __ mov(r2, Operand(r2, LSL, HeapNumber::kNonMantissaBitsInTopWord));
+      // Or with all low-bits of mantissa.
+      __ ldr(r3, FieldMemOperand(r0, HeapNumber::kMantissaOffset));
+      __ orr(r0, r3, Operand(r2), SetCC);
+      // For equal we already have the right value in r0:  Return zero (equal)
+      // if all bits in mantissa are zero (it's an Infinity) and non-zero if not
+      // (it's a NaN).  For <= and >= we need to load r0 with the failing value
+      // if it's a NaN.
+      if (cc != eq) {
+        // All-zero means Infinity means equal.
+        __ mov(pc, Operand(lr), LeaveCC, eq);  // Return equal
+        if (cc == le) {
+          __ mov(r0, Operand(GREATER));  // NaN <= NaN should fail.
+        } else {
+          __ mov(r0, Operand(LESS));     // NaN >= NaN should fail.
+        }
       }
+      __ mov(pc, Operand(lr));  // Return.
     }
-    __ mov(pc, Operand(lr));  // Return.
+    // No fall through here.
   }
-  // No fall through here.
 
   __ bind(&not_identical);
 }
@@ -4979,6 +5019,14 @@
     // Check for oddballs: true, false, null, undefined.
     __ cmp(r3, Operand(ODDBALL_TYPE));
     __ b(eq, &return_not_equal);
+
+    // Now that we have the types we might as well check for symbol-symbol.
+    // Ensure that no non-strings have the symbol bit set.
+    ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
+    ASSERT(kSymbolTag != 0);
+    __ and_(r2, r2, Operand(r3));
+    __ tst(r2, Operand(kIsSymbolMask));
+    __ b(ne, &return_not_equal);
 }
 
 
@@ -5005,12 +5053,13 @@
 // Fast negative check for symbol-to-symbol equality.
 static void EmitCheckForSymbols(MacroAssembler* masm, Label* slow) {
   // r2 is object type of r0.
-  __ tst(r2, Operand(kIsNotStringMask));
-  __ b(ne, slow);
+  // Ensure that no non-strings have the symbol bit set.
+  ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
+  ASSERT(kSymbolTag != 0);
   __ tst(r2, Operand(kIsSymbolMask));
   __ b(eq, slow);
-  __ CompareObjectType(r1, r3, r3, FIRST_NONSTRING_TYPE);
-  __ b(ge, slow);
+  __ ldr(r3, FieldMemOperand(r1, HeapObject::kMapOffset));
+  __ ldrb(r3, FieldMemOperand(r3, Map::kInstanceTypeOffset));
   __ tst(r3, Operand(kIsSymbolMask));
   __ b(eq, slow);
 
@@ -5032,7 +5081,7 @@
 
   // Handle the case where the objects are identical.  Either returns the answer
   // or goes to slow.  Only falls through if the objects were not identical.
-  EmitIdenticalObjectComparison(masm, &slow, cc_);
+  EmitIdenticalObjectComparison(masm, &slow, cc_, never_nan_nan_);
 
   // If either is a Smi (we know that not both are), then they can only
   // be strictly equal if the other is a HeapNumber.
@@ -5096,19 +5145,19 @@
                              &slow);
 
   __ bind(&check_for_symbols);
-  if (cc_ == eq) {
+  // In the strict case the EmitStrictTwoHeapObjectCompare already took care of
+  // symbols.
+  if (cc_ == eq && !strict_) {
     // Either jumps to slow or returns the answer.  Assumes that r2 is the type
     // of r0 on entry.
     EmitCheckForSymbols(masm, &slow);
   }
 
   __ bind(&slow);
-  __ push(lr);
   __ push(r1);
   __ push(r0);
   // Figure out which native to call and setup the arguments.
   Builtins::JavaScript native;
-  int arg_count = 1;  // Not counting receiver.
   if (cc_ == eq) {
     native = strict_ ? Builtins::STRICT_EQUALS : Builtins::EQUALS;
   } else {
@@ -5120,16 +5169,13 @@
       ASSERT(cc_ == gt || cc_ == ge);  // remaining cases
       ncr = LESS;
     }
-    arg_count++;
     __ mov(r0, Operand(Smi::FromInt(ncr)));
     __ push(r0);
   }
 
   // Call the native; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
-  __ InvokeBuiltin(native, CALL_JS);
-  __ cmp(r0, Operand(0));
-  __ pop(pc);
+  __ InvokeBuiltin(native, JUMP_JS);
 }
 
 
@@ -5955,7 +6001,9 @@
 }
 
 
-void UnarySubStub::Generate(MacroAssembler* masm) {
+void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
+  ASSERT(op_ == Token::SUB);
+
   Label undo;
   Label slow;
   Label not_smi;
@@ -6579,10 +6627,53 @@
 }
 
 
+const char* CompareStub::GetName() {
+  switch (cc_) {
+    case lt: return "CompareStub_LT";
+    case gt: return "CompareStub_GT";
+    case le: return "CompareStub_LE";
+    case ge: return "CompareStub_GE";
+    case ne: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_NE_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_NO_NAN";
+        } else {
+          return "CompareStub_NE";
+        }
+      }
+    }
+    case eq: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_EQ_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_NO_NAN";
+        } else {
+          return "CompareStub_EQ";
+        }
+      }
+    }
+    default: return "CompareStub";
+  }
+}
+
+
 int CompareStub::MinorKey() {
-  // Encode the two parameters in a unique 16 bit value.
-  ASSERT(static_cast<unsigned>(cc_) >> 28 < (1 << 15));
-  return (static_cast<unsigned>(cc_) >> 27) | (strict_ ? 1 : 0);
+  // Encode the three parameters in a unique 16 bit value.
+  ASSERT((static_cast<unsigned>(cc_) >> 26) < (1 << 16));
+  int nnn_value = (never_nan_nan_ ? 2 : 0);
+  if (cc_ != eq) nnn_value = 0;  // Avoid duplicate stubs.
+  return (static_cast<unsigned>(cc_) >> 26) | nnn_value | (strict_ ? 1 : 0);
 }
 
 
diff --git a/src/arm/codegen-arm.h b/src/arm/codegen-arm.h
index e9f11e9..b62bc36 100644
--- a/src/arm/codegen-arm.h
+++ b/src/arm/codegen-arm.h
@@ -272,6 +272,9 @@
 
   // Read a value from a slot and leave it on top of the expression stack.
   void LoadFromSlot(Slot* slot, TypeofState typeof_state);
+  // Store the value on top of the stack to a slot.
+  void StoreToSlot(Slot* slot, InitState init_state);
+
   void LoadFromGlobalSlotCheckExtensions(Slot* slot,
                                          TypeofState typeof_state,
                                          Register tmp,
@@ -360,15 +363,18 @@
   // Fast support for Math.random().
   void GenerateRandomPositiveSmi(ZoneList<Expression*>* args);
 
-  // Fast support for Math.sin and Math.cos.
-  enum MathOp { SIN, COS };
-  void GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args);
-  inline void GenerateMathSin(ZoneList<Expression*>* args);
-  inline void GenerateMathCos(ZoneList<Expression*>* args);
-
   // Fast support for StringAdd.
   void GenerateStringAdd(ZoneList<Expression*>* args);
 
+  // Fast support for SubString.
+  void GenerateSubString(ZoneList<Expression*>* args);
+
+  // Fast support for StringCompare.
+  void GenerateStringCompare(ZoneList<Expression*>* args);
+
+  // Support for direct calls from JavaScript to native RegExp code.
+  void GenerateRegExpExec(ZoneList<Expression*>* args);
+
   // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,
diff --git a/src/arm/cpu-arm.cc b/src/arm/cpu-arm.cc
index a5a358b..4e39cda 100644
--- a/src/arm/cpu-arm.cc
+++ b/src/arm/cpu-arm.cc
@@ -61,28 +61,32 @@
       reinterpret_cast<uint32_t>(start) + size;
   register uint32_t flg asm("a3") = 0;
   #ifdef __ARM_EABI__
-    register uint32_t scno asm("r7") = __ARM_NR_cacheflush;
     #if defined (__arm__) && !defined(__thumb__)
       // __arm__ may be defined in thumb mode.
+      register uint32_t scno asm("r7") = __ARM_NR_cacheflush;
       asm volatile(
           "swi 0x0"
           : "=r" (beg)
           : "0" (beg), "r" (end), "r" (flg), "r" (scno));
     #else
+      // r7 is reserved by the EABI in thumb mode.
       asm volatile(
       "@   Enter ARM Mode  \n\t"
           "adr r3, 1f      \n\t"
           "bx  r3          \n\t"
           ".ALIGN 4        \n\t"
           ".ARM            \n"
-      "1:  swi 0x0         \n\t"
+      "1:  push {r7}       \n\t"
+          "mov r7, %4      \n\t"
+          "swi 0x0         \n\t"
+          "pop {r7}        \n\t"
       "@   Enter THUMB Mode\n\t"
           "adr r3, 2f+1    \n\t"
           "bx  r3          \n\t"
           ".THUMB          \n"
       "2:                  \n\t"
           : "=r" (beg)
-          : "0" (beg), "r" (end), "r" (flg), "r" (scno)
+          : "0" (beg), "r" (end), "r" (flg), "r" (__ARM_NR_cacheflush)
           : "r3");
     #endif
   #else
diff --git a/src/arm/fast-codegen-arm.cc b/src/arm/fast-codegen-arm.cc
index 55d87b7..0d934b5 100644
--- a/src/arm/fast-codegen-arm.cc
+++ b/src/arm/fast-codegen-arm.cc
@@ -214,185 +214,163 @@
 }
 
 
-void FastCodeGenerator::Move(Expression::Context context, Register source) {
+void FastCodeGenerator::Apply(Expression::Context context,
+                              Slot* slot,
+                              Register scratch) {
   switch (context) {
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
       break;
     case Expression::kValue:
-      __ push(source);
+    case Expression::kTest:
+    case Expression::kValueTest:
+    case Expression::kTestValue:
+      Move(scratch, slot);
+      Apply(context, scratch);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Apply(Expression::Context context, Literal* lit) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      break;
+    case Expression::kValue:
+    case Expression::kTest:
+    case Expression::kValueTest:
+    case Expression::kTestValue:
+      __ mov(ip, Operand(lit->handle()));
+      Apply(context, ip);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::ApplyTOS(Expression::Context context) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(1);
+      break;
+    case Expression::kValue:
       break;
     case Expression::kTest:
-      TestAndBranch(source, true_label_, false_label_);
+      __ pop(r0);
+      TestAndBranch(r0, true_label_, false_label_);
       break;
     case Expression::kValueTest: {
       Label discard;
-      __ push(source);
-      TestAndBranch(source, true_label_, &discard);
+      __ ldr(r0, MemOperand(sp, 0));
+      TestAndBranch(r0, true_label_, &discard);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
     case Expression::kTestValue: {
       Label discard;
-      __ push(source);
-      TestAndBranch(source, &discard, false_label_);
+      __ ldr(r0, MemOperand(sp, 0));
+      TestAndBranch(r0, &discard, false_label_);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(true_label_);
     }
   }
 }
 
 
-template <>
-MemOperand FastCodeGenerator::CreateSlotOperand<MemOperand>(
-    Slot* source,
-    Register scratch) {
-  switch (source->type()) {
-    case Slot::PARAMETER:
-    case Slot::LOCAL:
-      return MemOperand(fp, SlotOffset(source));
-    case Slot::CONTEXT: {
-      int context_chain_length =
-          function_->scope()->ContextChainLength(source->var()->scope());
-      __ LoadContext(scratch, context_chain_length);
-      return CodeGenerator::ContextOperand(scratch, source->index());
+void FastCodeGenerator::DropAndApply(int count,
+                                     Expression::Context context,
+                                     Register reg) {
+  ASSERT(count > 0);
+  ASSERT(!reg.is(sp));
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(count);
+      break;
+    case Expression::kValue:
+      if (count > 1) __ Drop(count - 1);
+      __ str(reg, MemOperand(sp));
+      break;
+    case Expression::kTest:
+      __ Drop(count);
+      TestAndBranch(reg, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ str(reg, MemOperand(sp));
+      TestAndBranch(reg, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
       break;
     }
+    case Expression::kTestValue: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ str(reg, MemOperand(sp));
+      TestAndBranch(reg, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(true_label_);
+      break;
+    }
+  }
+}
+
+
+MemOperand FastCodeGenerator::EmitSlotSearch(Slot* slot, Register scratch) {
+  switch (slot->type()) {
+    case Slot::PARAMETER:
+    case Slot::LOCAL:
+      return MemOperand(fp, SlotOffset(slot));
+    case Slot::CONTEXT: {
+      int context_chain_length =
+          function_->scope()->ContextChainLength(slot->var()->scope());
+      __ LoadContext(scratch, context_chain_length);
+      return CodeGenerator::ContextOperand(scratch, slot->index());
+    }
     case Slot::LOOKUP:
-      UNIMPLEMENTED();
-      // Fall-through.
-    default:
       UNREACHABLE();
-      return MemOperand(r0, 0);  // Dead code to make the compiler happy.
   }
+  UNREACHABLE();
+  return MemOperand(r0, 0);
 }
 
 
-void FastCodeGenerator::Move(Register dst, Slot* source) {
-  // Use dst as scratch.
-  MemOperand location = CreateSlotOperand<MemOperand>(source, dst);
-  __ ldr(dst, location);
+void FastCodeGenerator::Move(Register destination, Slot* source) {
+  // Use destination as scratch.
+  MemOperand location = EmitSlotSearch(source, destination);
+  __ ldr(destination, location);
 }
 
 
 
-void FastCodeGenerator::Move(Expression::Context context,
-                             Slot* source,
-                             Register scratch) {
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      break;
-    case Expression::kValue:  // Fall through.
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
-    case Expression::kTestValue:
-      Move(scratch, source);
-      Move(context, scratch);
-      break;
-  }
-}
-
-
-void FastCodeGenerator::Move(Expression::Context context, Literal* expr) {
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      break;
-    case Expression::kValue:  // Fall through.
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
-    case Expression::kTestValue:
-      __ mov(ip, Operand(expr->handle()));
-      Move(context, ip);
-      break;
-  }
-}
-
-
 void FastCodeGenerator::Move(Slot* dst,
                              Register src,
                              Register scratch1,
                              Register scratch2) {
-  switch (dst->type()) {
-    case Slot::PARAMETER:
-    case Slot::LOCAL:
-      __ str(src, MemOperand(fp, SlotOffset(dst)));
-      break;
-    case Slot::CONTEXT: {
-      int context_chain_length =
-          function_->scope()->ContextChainLength(dst->var()->scope());
-      __ LoadContext(scratch1, context_chain_length);
-      int index = Context::SlotOffset(dst->index());
-      __ mov(scratch2, Operand(index));
-      __ str(src, MemOperand(scratch1, index));
-      __ RecordWrite(scratch1, scratch2, src);
-      break;
-    }
-    case Slot::LOOKUP:
-      UNIMPLEMENTED();
-    default:
-      UNREACHABLE();
+  ASSERT(dst->type() != Slot::LOOKUP);  // Not yet implemented.
+  ASSERT(!scratch1.is(src) && !scratch2.is(src));
+  MemOperand location = EmitSlotSearch(dst, scratch1);
+  __ str(src, location);
+  // Emit the write barrier code if the location is in the heap.
+  if (dst->type() == Slot::CONTEXT) {
+    __ mov(scratch2, Operand(Context::SlotOffset(dst->index())));
+    __ RecordWrite(scratch1, scratch2, src);
   }
 }
 
 
 
-void FastCodeGenerator::DropAndMove(Expression::Context context,
-                                    Register source,
-                                    int drop_count) {
-  ASSERT(drop_count > 0);
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      __ add(sp, sp, Operand(drop_count * kPointerSize));
-      break;
-    case Expression::kValue:
-      if (drop_count > 1) {
-        __ add(sp, sp, Operand((drop_count - 1) * kPointerSize));
-      }
-      __ str(source, MemOperand(sp));
-      break;
-    case Expression::kTest:
-      ASSERT(!source.is(sp));
-      __ add(sp, sp, Operand(drop_count * kPointerSize));
-      TestAndBranch(source, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      if (drop_count > 1) {
-        __ add(sp, sp, Operand((drop_count - 1) * kPointerSize));
-      }
-      __ str(source, MemOperand(sp));
-      TestAndBranch(source, true_label_, &discard);
-      __ bind(&discard);
-      __ pop();
-      __ jmp(false_label_);
-      break;
-    }
-    case Expression::kTestValue: {
-      Label discard;
-      if (drop_count > 1) {
-        __ add(sp, sp, Operand((drop_count - 1) * kPointerSize));
-      }
-      __ str(source, MemOperand(sp));
-      TestAndBranch(source, &discard, false_label_);
-      __ bind(&discard);
-      __ pop();
-      __ jmp(true_label_);
-      break;
-    }
-  }
-}
-
-
 void FastCodeGenerator::TestAndBranch(Register source,
                                       Label* true_label,
                                       Label* false_label) {
@@ -418,19 +396,22 @@
 
   if (slot != NULL) {
     switch (slot->type()) {
-      case Slot::PARAMETER:  // Fall through.
+      case Slot::PARAMETER:
       case Slot::LOCAL:
         if (decl->mode() == Variable::CONST) {
           __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-          __ str(ip, MemOperand(fp, SlotOffset(var->slot())));
+          __ str(ip, MemOperand(fp, SlotOffset(slot)));
         } else if (decl->fun() != NULL) {
           Visit(decl->fun());
           __ pop(ip);
-          __ str(ip, MemOperand(fp, SlotOffset(var->slot())));
+          __ str(ip, MemOperand(fp, SlotOffset(slot)));
         }
         break;
 
       case Slot::CONTEXT:
+        // We bypass the general EmitSlotSearch because we know more about
+        // this specific context.
+
         // The variable in the decl always resides in the current context.
         ASSERT_EQ(0, function_->scope()->ContextChainLength(var->scope()));
         if (FLAG_debug_code) {
@@ -504,7 +485,7 @@
 
       // Value in r0 is ignored (declarations are statements).  Receiver
       // and key on stack are discarded.
-      __ add(sp, sp, Operand(2 * kPointerSize));
+      __ Drop(2);
     }
   }
 }
@@ -535,7 +516,7 @@
   __ mov(r0, Operand(boilerplate));
   __ stm(db_w, sp, cp.bit() | r0.bit());
   __ CallRuntime(Runtime::kNewClosure, 2);
-  Move(expr->context(), r0);
+  Apply(expr->context(), r0);
 }
 
 
@@ -558,13 +539,13 @@
     __ mov(r2, Operand(var->name()));
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET_CONTEXT);
-    DropAndMove(context, r0);
+    DropAndApply(1, context, r0);
   } else if (rewrite->AsSlot() != NULL) {
     Slot* slot = rewrite->AsSlot();
     if (FLAG_debug_code) {
       switch (slot->type()) {
-        case Slot::LOCAL:
-        case Slot::PARAMETER: {
+        case Slot::PARAMETER:
+        case Slot::LOCAL: {
           Comment cmnt(masm_, "Stack slot");
           break;
         }
@@ -575,21 +556,20 @@
         case Slot::LOOKUP:
           UNIMPLEMENTED();
           break;
-        default:
-          UNREACHABLE();
       }
     }
-    Move(context, slot, r0);
+    Apply(context, slot, r0);
   } else {
-    // A variable has been rewritten into an explicit access to
-    // an object property.
+    Comment cmnt(masm_, "Variable rewritten to property");
+    // A variable has been rewritten into an explicit access to an object
+    // property.
     Property* property = rewrite->AsProperty();
     ASSERT_NOT_NULL(property);
 
-    // Currently the only parameter expressions that can occur are
-    // on the form "slot[literal]".
+    // The only property expressions that can occur are of the form
+    // "slot[literal]".
 
-    // Check that the object is in a slot.
+    // Assert that the object is in a slot.
     Variable* object_var = property->obj()->AsVariableProxy()->AsVariable();
     ASSERT_NOT_NULL(object_var);
     Slot* object_slot = object_var->slot();
@@ -598,7 +578,7 @@
     // Load the object.
     Move(r2, object_slot);
 
-    // Check that the key is a smi.
+    // Assert that the key is a smi.
     Literal* key_literal = property->key()->AsLiteral();
     ASSERT_NOT_NULL(key_literal);
     ASSERT(key_literal->handle()->IsSmi());
@@ -609,12 +589,12 @@
     // Push both as arguments to ic.
     __ stm(db_w, sp, r2.bit() | r1.bit());
 
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET);
 
     // Drop key and object left on the stack by IC, and push the result.
-    DropAndMove(context, r0, 2);
+    DropAndApply(2, context, r0);
   }
 }
 
@@ -642,7 +622,7 @@
   __ stm(db_w, sp, r4.bit() | r3.bit() | r2.bit() | r1.bit());
   __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   __ bind(&done);
-  Move(expr->context(), r0);
+  Apply(expr->context(), r0);
 }
 
 
@@ -704,7 +684,7 @@
         __ ldr(r0, MemOperand(sp));  // Restore result into r0.
         break;
 
-      case ObjectLiteral::Property::GETTER:  // Fall through.
+      case ObjectLiteral::Property::GETTER:
       case ObjectLiteral::Property::SETTER:
         __ push(r0);
         Visit(key);
@@ -724,7 +704,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ pop();
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(r0);
@@ -738,7 +718,7 @@
       if (!result_saved) __ push(r0);
       TestAndBranch(r0, true_label_, &discard);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -747,7 +727,7 @@
       if (!result_saved) __ push(r0);
       TestAndBranch(r0, &discard, false_label_);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -760,7 +740,7 @@
   __ ldr(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   __ ldr(r3, FieldMemOperand(r3, JSFunction::kLiteralsOffset));
   __ mov(r2, Operand(Smi::FromInt(expr->literal_index())));
-  __ mov(r1, Operand(expr->literals()));
+  __ mov(r1, Operand(expr->constant_elements()));
   __ stm(db_w, sp, r3.bit() | r2.bit() | r1.bit());
   if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateArrayLiteral, 3);
@@ -806,7 +786,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ pop();
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(r0);
@@ -820,7 +800,7 @@
       if (!result_saved) __ push(r0);
       TestAndBranch(r0, true_label_, &discard);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -829,7 +809,7 @@
       if (!result_saved) __ push(r0);
       TestAndBranch(r0, &discard, false_label_);
       __ bind(&discard);
-      __ pop();
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -839,18 +819,21 @@
 
 void FastCodeGenerator::EmitNamedPropertyLoad(Property* prop,
                                               Expression::Context context) {
+  SetSourcePosition(prop->position());
   Literal* key = prop->key()->AsLiteral();
   __ mov(r2, Operand(key->handle()));
   Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
   __ Call(ic, RelocInfo::CODE_TARGET);
-  Move(context, r0);
+  Apply(context, r0);
 }
 
 
-void FastCodeGenerator::EmitKeyedPropertyLoad(Expression::Context context) {
+void FastCodeGenerator::EmitKeyedPropertyLoad(Property* prop,
+                                              Expression::Context context) {
+  SetSourcePosition(prop->position());
   Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
   __ Call(ic, RelocInfo::CODE_TARGET);
-  Move(context, r0);
+  Apply(context, r0);
 }
 
 
@@ -861,12 +844,12 @@
   GenericBinaryOpStub stub(op,
                            NO_OVERWRITE);
   __ CallStub(&stub);
-  Move(context, r0);
+  Apply(context, r0);
 }
 
 
-void FastCodeGenerator::EmitVariableAssignment(Assignment* expr) {
-  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
+void FastCodeGenerator::EmitVariableAssignment(Variable* var,
+                                               Expression::Context context) {
   ASSERT(var != NULL);
   ASSERT(var->is_global() || var->slot() != NULL);
   if (var->is_global()) {
@@ -880,50 +863,50 @@
     Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET);
     // Overwrite the global object on the stack with the result if needed.
-    DropAndMove(expr->context(), r0);
+    DropAndApply(1, context, r0);
 
-  } else if (var->slot()) {
+  } else if (var->slot() != NULL) {
     Slot* slot = var->slot();
-    ASSERT_NOT_NULL(slot);  // Variables rewritten as properties not handled.
     switch (slot->type()) {
       case Slot::LOCAL:
       case Slot::PARAMETER: {
-        switch (expr->context()) {
+        MemOperand target = MemOperand(fp, SlotOffset(slot));
+        switch (context) {
           case Expression::kUninitialized:
             UNREACHABLE();
           case Expression::kEffect:
             // Perform assignment and discard value.
             __ pop(r0);
-            __ str(r0, MemOperand(fp, SlotOffset(var->slot())));
+            __ str(r0, target);
             break;
           case Expression::kValue:
             // Perform assignment and preserve value.
             __ ldr(r0, MemOperand(sp));
-            __ str(r0, MemOperand(fp, SlotOffset(var->slot())));
+            __ str(r0, target);
             break;
           case Expression::kTest:
             // Perform assignment and test (and discard) value.
             __ pop(r0);
-            __ str(r0, MemOperand(fp, SlotOffset(var->slot())));
+            __ str(r0, target);
             TestAndBranch(r0, true_label_, false_label_);
             break;
           case Expression::kValueTest: {
             Label discard;
             __ ldr(r0, MemOperand(sp));
-            __ str(r0, MemOperand(fp, SlotOffset(var->slot())));
+            __ str(r0, target);
             TestAndBranch(r0, true_label_, &discard);
             __ bind(&discard);
-            __ pop();
+            __ Drop(1);
             __ jmp(false_label_);
             break;
           }
           case Expression::kTestValue: {
             Label discard;
             __ ldr(r0, MemOperand(sp));
-            __ str(r0, MemOperand(fp, SlotOffset(var->slot())));
+            __ str(r0, target);
             TestAndBranch(r0, &discard, false_label_);
             __ bind(&discard);
-            __ pop();
+            __ Drop(1);
             __ jmp(true_label_);
             break;
           }
@@ -932,31 +915,15 @@
       }
 
       case Slot::CONTEXT: {
-        int chain_length =
-            function_->scope()->ContextChainLength(slot->var()->scope());
-        if (chain_length > 0) {
-          // Move up the chain of contexts to the context containing the slot.
-          __ ldr(r0, CodeGenerator::ContextOperand(cp, Context::CLOSURE_INDEX));
-          // Load the function context (which is the incoming, outer context).
-          __ ldr(r0, FieldMemOperand(r0, JSFunction::kContextOffset));
-          for (int i = 1; i < chain_length; i++) {
-            __ ldr(r0,
-                   CodeGenerator::ContextOperand(r0, Context::CLOSURE_INDEX));
-            __ ldr(r0, FieldMemOperand(r0, JSFunction::kContextOffset));
-          }
-        } else {  // Slot is in the current context.  Generate optimized code.
-          __ mov(r0, cp);
-        }
-        // The context may be an intermediate context, not a function context.
-        __ ldr(r0, CodeGenerator::ContextOperand(r0, Context::FCONTEXT_INDEX));
-        __ pop(r1);
-        __ str(r1, CodeGenerator::ContextOperand(r0, slot->index()));
+        MemOperand target = EmitSlotSearch(slot, r1);
+        __ pop(r0);
+        __ str(r0, target);
 
         // RecordWrite may destroy all its register arguments.
-        if (expr->context() == Expression::kValue) {
-          __ push(r1);
-        } else if (expr->context() != Expression::kEffect) {
-          __ mov(r3, r1);
+        if (context == Expression::kValue) {
+          __ push(r0);
+        } else if (context != Expression::kEffect) {
+          __ mov(r3, r0);
         }
         int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
 
@@ -964,15 +931,14 @@
         // register.  Skip the write barrier if the value written (r1) is a smi.
         // The smi test is part of RecordWrite on other platforms, not on arm.
         Label exit;
-        __ tst(r1, Operand(kSmiTagMask));
+        __ tst(r0, Operand(kSmiTagMask));
         __ b(eq, &exit);
 
         __ mov(r2, Operand(offset));
-        __ RecordWrite(r0, r2, r1);
+        __ RecordWrite(r1, r2, r0);
         __ bind(&exit);
-        if (expr->context() != Expression::kEffect &&
-            expr->context() != Expression::kValue) {
-        Move(expr->context(), r3);
+        if (context != Expression::kEffect && context != Expression::kValue) {
+          Apply(context, r3);
         }
         break;
       }
@@ -981,6 +947,10 @@
         UNREACHABLE();
         break;
     }
+  } else {
+    // Variables rewritten as properties are not treated as variables in
+    // assignments.
+    UNREACHABLE();
   }
 }
 
@@ -1014,7 +984,7 @@
     __ pop(r0);
   }
 
-  DropAndMove(expr->context(), r0);
+  DropAndApply(1, expr->context(), r0);
 }
 
 
@@ -1025,7 +995,7 @@
   // change to slow case to avoid the quadratic behavior of repeatedly
   // adding fast properties.
   if (expr->starts_initialization_block()) {
-    // Reciever is under the key and value.
+    // Receiver is under the key and value.
     __ ldr(ip, MemOperand(sp, 2 * kPointerSize));
     __ push(ip);
     __ CallRuntime(Runtime::kToSlowProperties, 1);
@@ -1046,15 +1016,13 @@
   }
 
   // Receiver and key are still on stack.
-  __ add(sp, sp, Operand(2 * kPointerSize));
-  Move(expr->context(), r0);
+  DropAndApply(2, expr->context(), r0);
 }
 
 
 void FastCodeGenerator::VisitProperty(Property* expr) {
   Comment cmnt(masm_, "[ Property");
   Expression* key = expr->key();
-  uint32_t dummy;
 
   // Record the source position for the property load.
   SetSourcePosition(expr->position());
@@ -1062,22 +1030,21 @@
   // Evaluate receiver.
   Visit(expr->obj());
 
-  if (key->AsLiteral() != NULL && key->AsLiteral()->handle()->IsSymbol() &&
-      !String::cast(*(key->AsLiteral()->handle()))->AsArrayIndex(&dummy)) {
-    // Do a NAMED property load.
-    // The IC expects the property name in r2 and the receiver on the stack.
+  if (key->IsPropertyName()) {
+    // Do a named property load.  The IC expects the property name in r2 and
+    // the receiver on the stack.
     __ mov(r2, Operand(key->AsLiteral()->handle()));
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET);
+    DropAndApply(1, expr->context(), r0);
   } else {
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Visit(expr->key());
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET);
     // Drop key and receiver left on the stack by IC.
-    __ pop();
+    DropAndApply(2, expr->context(), r0);
   }
-  DropAndMove(expr->context(), r0);
 }
 
 void FastCodeGenerator::EmitCallWithIC(Call* expr,
@@ -1099,7 +1066,7 @@
   // Restore context register.
   __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
-  DropAndMove(expr->context(), r0);
+  DropAndApply(1, expr->context(), r0);
 }
 
 
@@ -1117,7 +1084,7 @@
   // Restore context register.
   __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
-  DropAndMove(expr->context(), r0);
+  DropAndApply(1, expr->context(), r0);
 }
 
 
@@ -1162,6 +1129,7 @@
       // Load receiver object into r1.
       if (prop->is_synthetic()) {
         __ ldr(r1, CodeGenerator::GlobalObject());
+        __ ldr(r1, FieldMemOperand(r1, GlobalObject::kGlobalReceiverOffset));
       } else {
         __ ldr(r1, MemOperand(sp, kPointerSize));
       }
@@ -1219,14 +1187,14 @@
 
   // Load function, arg_count into r1 and r0.
   __ mov(r0, Operand(arg_count));
-  // Function is in esp[arg_count + 1].
+  // Function is in sp[arg_count + 1].
   __ ldr(r1, MemOperand(sp, (arg_count + 1) * kPointerSize));
 
   Handle<Code> construct_builtin(Builtins::builtin(Builtins::JSConstructCall));
   __ Call(construct_builtin, RelocInfo::CONSTRUCT_CALL);
 
   // Replace function on TOS with result in r0, or pop it.
-  DropAndMove(expr->context(), r0);
+  DropAndApply(1, expr->context(), r0);
 }
 
 
@@ -1257,11 +1225,11 @@
     // Restore context register.
     __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Discard the function left on TOS.
-    DropAndMove(expr->context(), r0);
+    DropAndApply(1, expr->context(), r0);
   } else {
     // Call the C runtime function.
     __ CallRuntime(expr->function(), arg_count);
-    Move(expr->context(), r0);
+    Apply(expr->context(), r0);
   }
 }
 
@@ -1286,7 +1254,7 @@
           // Value is false so it's needed.
           __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
           __ push(ip);
-        case Expression::kTest:  // Fall through.
+        case Expression::kTest:
         case Expression::kValueTest:
           __ jmp(false_label_);
           break;
@@ -1298,20 +1266,19 @@
       Comment cmnt(masm_, "[ UnaryOperation (NOT)");
       ASSERT_EQ(Expression::kTest, expr->expression()->context());
 
-      Label push_true;
-      Label push_false;
-      Label done;
-      Label* saved_true = true_label_;
-      Label* saved_false = false_label_;
+      Label push_true, push_false, done;
       switch (expr->context()) {
         case Expression::kUninitialized:
           UNREACHABLE();
           break;
 
+        case Expression::kEffect:
+          VisitForControl(expr->expression(), &done, &done);
+          __ bind(&done);
+          break;
+
         case Expression::kValue:
-          true_label_ = &push_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, &push_true);
           __ bind(&push_true);
           __ LoadRoot(ip, Heap::kTrueValueRootIndex);
           __ push(ip);
@@ -1322,41 +1289,26 @@
           __ bind(&done);
           break;
 
-        case Expression::kEffect:
-          true_label_ = &done;
-          false_label_ = &done;
-          Visit(expr->expression());
-          __ bind(&done);
-          break;
-
         case Expression::kTest:
-          true_label_ = saved_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, true_label_);
           break;
 
         case Expression::kValueTest:
-          true_label_ = saved_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, &push_true);
           __ bind(&push_true);
           __ LoadRoot(ip, Heap::kTrueValueRootIndex);
           __ push(ip);
-          __ jmp(saved_true);
+          __ jmp(true_label_);
           break;
 
         case Expression::kTestValue:
-          true_label_ = &push_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, true_label_);
           __ bind(&push_false);
           __ LoadRoot(ip, Heap::kFalseValueRootIndex);
           __ push(ip);
-          __ jmp(saved_false);
+          __ jmp(false_label_);
           break;
       }
-      true_label_ = saved_true;
-      false_label_ = saved_false;
       break;
     }
 
@@ -1390,7 +1342,7 @@
       }
 
       __ CallRuntime(Runtime::kTypeof, 1);
-      Move(expr->context(), r0);
+      Apply(expr->context(), r0);
       break;
     }
 
@@ -1402,73 +1354,127 @@
 
 void FastCodeGenerator::VisitCountOperation(CountOperation* expr) {
   Comment cmnt(masm_, "[ CountOperation");
-  VariableProxy* proxy = expr->expression()->AsVariableProxy();
-  ASSERT(proxy->AsVariable() != NULL);
-  ASSERT(proxy->AsVariable()->is_global());
 
-  Visit(proxy);
+  // Expression can only be a property, a global or a (parameter or local)
+  // slot. Variables with rewrite to .arguments are treated as KEYED_PROPERTY.
+  enum LhsKind { VARIABLE, NAMED_PROPERTY, KEYED_PROPERTY };
+  LhsKind assign_type = VARIABLE;
+  Property* prop = expr->expression()->AsProperty();
+  // In case of a property we use the uninitialized expression context
+  // of the key to detect a named property.
+  if (prop != NULL) {
+    assign_type = (prop->key()->context() == Expression::kUninitialized)
+        ? NAMED_PROPERTY
+        : KEYED_PROPERTY;
+  }
+
+  // Evaluate expression and get value.
+  if (assign_type == VARIABLE) {
+    ASSERT(expr->expression()->AsVariableProxy()->var() != NULL);
+    EmitVariableLoad(expr->expression()->AsVariableProxy()->var(),
+                     Expression::kValue);
+  } else {
+    // Reserve space for result of postfix operation.
+    if (expr->is_postfix() && expr->context() != Expression::kEffect) {
+      ASSERT(expr->context() != Expression::kUninitialized);
+      __ mov(ip, Operand(Smi::FromInt(0)));
+      __ push(ip);
+    }
+    Visit(prop->obj());
+    ASSERT_EQ(Expression::kValue, prop->obj()->context());
+    if (assign_type == NAMED_PROPERTY) {
+      EmitNamedPropertyLoad(prop, Expression::kValue);
+    } else {
+      Visit(prop->key());
+      ASSERT_EQ(Expression::kValue, prop->key()->context());
+      EmitKeyedPropertyLoad(prop, Expression::kValue);
+    }
+  }
+
+  // Convert to number.
   __ InvokeBuiltin(Builtins::TO_NUMBER, CALL_JS);
 
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kValue:  // Fall through
-    case Expression::kTest:  // Fall through
-    case Expression::kTestValue:  // Fall through
-    case Expression::kValueTest:
-      // Duplicate the result on the stack.
-      __ push(r0);
-      break;
-    case Expression::kEffect:
-      // Do not save result.
-      break;
+  // Save result for postfix expressions.
+  if (expr->is_postfix()) {
+    switch (expr->context()) {
+      case Expression::kUninitialized:
+        UNREACHABLE();
+      case Expression::kEffect:
+        // Do not save result.
+        break;
+      case Expression::kValue:
+      case Expression::kTest:
+      case Expression::kTestValue:
+      case Expression::kValueTest:
+        // Save the result on the stack. If we have a named or keyed property
+        // we store the result under the receiver that is currently on top
+        // of the stack.
+        switch (assign_type) {
+          case VARIABLE:
+            __ push(r0);
+            break;
+          case NAMED_PROPERTY:
+            __ str(r0, MemOperand(sp, kPointerSize));
+            break;
+          case KEYED_PROPERTY:
+            __ str(r0, MemOperand(sp, 2 * kPointerSize));
+            break;
+        }
+        break;
+    }
   }
-  // Call runtime for +1/-1.
-  __ push(r0);
-  __ mov(ip, Operand(Smi::FromInt(1)));
-  __ push(ip);
-  if (expr->op() == Token::INC) {
-    __ CallRuntime(Runtime::kNumberAdd, 2);
-  } else {
-    __ CallRuntime(Runtime::kNumberSub, 2);
-  }
-  // Call Store IC.
-  __ mov(r2, Operand(proxy->AsVariable()->name()));
-  __ ldr(ip, CodeGenerator::GlobalObject());
-  __ push(ip);
-  Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
-  __ Call(ic, RelocInfo::CODE_TARGET);
-  // Restore up stack after store IC.
-  __ add(sp, sp, Operand(kPointerSize));
 
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:  // Fall through
-    case Expression::kValue:
-      // Do nothing. Result in either on the stack for value context
-      // or discarded for effect context.
+  // Call runtime for +1/-1.
+  if (expr->op() == Token::INC) {
+    __ mov(ip, Operand(Smi::FromInt(1)));
+  } else {
+    __ mov(ip, Operand(Smi::FromInt(-1)));
+  }
+  __ stm(db_w, sp, ip.bit() | r0.bit());
+  __ CallRuntime(Runtime::kNumberAdd, 2);
+
+  // Store the value returned in r0.
+  switch (assign_type) {
+    case VARIABLE:
+      __ push(r0);
+      if (expr->is_postfix()) {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               Expression::kEffect);
+        // For all contexts except kEffect: We have the result on
+        // top of the stack.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               expr->context());
+      }
       break;
-    case Expression::kTest:
-      __ pop(r0);
-      TestAndBranch(r0, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      __ ldr(r0, MemOperand(sp));
-      TestAndBranch(r0, true_label_, &discard);
-      __ bind(&discard);
-      __ add(sp, sp, Operand(kPointerSize));
-      __ b(false_label_);
+    case NAMED_PROPERTY: {
+      __ mov(r2, Operand(prop->key()->AsLiteral()->handle()));
+      Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
+      __ Call(ic, RelocInfo::CODE_TARGET);
+      if (expr->is_postfix()) {
+        __ Drop(1);  // Result is on the stack under the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(1, expr->context(), r0);
+      }
       break;
     }
-    case Expression::kTestValue: {
-      Label discard;
-      __ ldr(r0, MemOperand(sp));
-      TestAndBranch(r0, &discard, false_label_);
-      __ bind(&discard);
-      __ add(sp, sp, Operand(kPointerSize));
-      __ b(true_label_);
+    case KEYED_PROPERTY: {
+      Handle<Code> ic(Builtins::builtin(Builtins::KeyedStoreIC_Initialize));
+      __ Call(ic, RelocInfo::CODE_TARGET);
+      if (expr->is_postfix()) {
+        __ Drop(2);  // Result is on the stack under the key and the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(2, expr->context(), r0);
+      }
       break;
     }
   }
@@ -1511,7 +1517,7 @@
       GenericBinaryOpStub stub(expr->op(),
                                NO_OVERWRITE);
       __ CallStub(&stub);
-      Move(expr->context(), r0);
+      Apply(expr->context(), r0);
 
       break;
     }
@@ -1528,47 +1534,41 @@
   Visit(expr->left());
   Visit(expr->right());
 
-  // Convert current context to test context: Pre-test code.
-  Label push_true;
-  Label push_false;
-  Label done;
-  Label* saved_true = true_label_;
-  Label* saved_false = false_label_;
+  // Always perform the comparison for its control flow.  Pack the result
+  // into the expression's context after the comparison is performed.
+  Label push_true, push_false, done;
+  // Initially assume we are in a test context.
+  Label* if_true = true_label_;
+  Label* if_false = false_label_;
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
-
-    case Expression::kValue:
-      true_label_ = &push_true;
-      false_label_ = &push_false;
-      break;
-
     case Expression::kEffect:
-      true_label_ = &done;
-      false_label_ = &done;
+      if_true = &done;
+      if_false = &done;
       break;
-
+    case Expression::kValue:
+      if_true = &push_true;
+      if_false = &push_false;
+      break;
     case Expression::kTest:
       break;
-
     case Expression::kValueTest:
-      true_label_ = &push_true;
+      if_true = &push_true;
       break;
-
     case Expression::kTestValue:
-      false_label_ = &push_false;
+      if_false = &push_false;
       break;
   }
-  // Convert current context to test context: End pre-test code.
 
   switch (expr->op()) {
     case Token::IN: {
       __ InvokeBuiltin(Builtins::IN, CALL_JS);
       __ LoadRoot(ip, Heap::kTrueValueRootIndex);
       __ cmp(r0, ip);
-      __ b(eq, true_label_);
-      __ jmp(false_label_);
+      __ b(eq, if_true);
+      __ jmp(if_false);
       break;
     }
 
@@ -1576,8 +1576,8 @@
       InstanceofStub stub;
       __ CallStub(&stub);
       __ tst(r0, r0);
-      __ b(eq, true_label_);  // The stub returns 0 for true.
-      __ jmp(false_label_);
+      __ b(eq, if_true);  // The stub returns 0 for true.
+      __ jmp(if_false);
       break;
     }
 
@@ -1628,24 +1628,29 @@
       __ tst(r2, Operand(kSmiTagMask));
       __ b(ne, &slow_case);
       __ cmp(r1, r0);
-      __ b(cc, true_label_);
-      __ jmp(false_label_);
+      __ b(cc, if_true);
+      __ jmp(if_false);
 
       __ bind(&slow_case);
       CompareStub stub(cc, strict);
       __ CallStub(&stub);
       __ tst(r0, r0);
-      __ b(cc, true_label_);
-      __ jmp(false_label_);
+      __ b(cc, if_true);
+      __ jmp(if_false);
     }
   }
 
-  // Convert current context to test context: Post-test code.
+  // Convert the result of the comparison into one expected for this
+  // expression's context.
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
 
+    case Expression::kEffect:
+      __ bind(&done);
+      break;
+
     case Expression::kValue:
       __ bind(&push_true);
       __ LoadRoot(ip, Heap::kTrueValueRootIndex);
@@ -1657,10 +1662,6 @@
       __ bind(&done);
       break;
 
-    case Expression::kEffect:
-      __ bind(&done);
-      break;
-
     case Expression::kTest:
       break;
 
@@ -1668,25 +1669,22 @@
       __ bind(&push_true);
       __ LoadRoot(ip, Heap::kTrueValueRootIndex);
       __ push(ip);
-      __ jmp(saved_true);
+      __ jmp(true_label_);
       break;
 
     case Expression::kTestValue:
       __ bind(&push_false);
       __ LoadRoot(ip, Heap::kFalseValueRootIndex);
       __ push(ip);
-      __ jmp(saved_false);
+      __ jmp(false_label_);
       break;
   }
-  true_label_ = saved_true;
-  false_label_ = saved_false;
-  // Convert current context to test context: End post-test code.
 }
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ ldr(r0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
-  Move(expr->context(), r0);
+  Apply(expr->context(), r0);
 }
 
 
@@ -1735,12 +1733,6 @@
 }
 
 
-void FastCodeGenerator::ThrowException() {
-  __ push(result_register());
-  __ CallRuntime(Runtime::kThrow, 1);
-}
-
-
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/arm/ic-arm.cc b/src/arm/ic-arm.cc
index b57aa93..a1f2613 100644
--- a/src/arm/ic-arm.cc
+++ b/src/arm/ic-arm.cc
@@ -618,6 +618,15 @@
 }
 
 
+void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
+  // ---------- S t a t e --------------
+  //  -- lr     : return address
+  //  -- sp[0]  : key
+  //  -- sp[4]  : receiver
+  GenerateGeneric(masm);
+}
+
+
 void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
                                         ExternalArrayType array_type) {
   // TODO(476): port specialized code.
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 876eec1..18cadac 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -162,9 +162,9 @@
 }
 
 
-void MacroAssembler::Drop(int stack_elements, Condition cond) {
-  if (stack_elements > 0) {
-    add(sp, sp, Operand(stack_elements * kPointerSize), LeaveCC, cond);
+void MacroAssembler::Drop(int count, Condition cond) {
+  if (count > 0) {
+    add(sp, sp, Operand(count * kPointerSize), LeaveCC, cond);
   }
 }
 
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index 88bfa9c..8f2064a 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -64,7 +64,11 @@
   void Call(byte* target, RelocInfo::Mode rmode, Condition cond = al);
   void Call(Handle<Code> code, RelocInfo::Mode rmode, Condition cond = al);
   void Ret(Condition cond = al);
-  void Drop(int stack_elements, Condition cond = al);
+
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the sp register.
+  void Drop(int count, Condition cond = al);
+
   void Call(Label* target);
   void Move(Register dst, Handle<Object> value);
   // Jumps to the label at the index given by the Smi in "index".
diff --git a/src/arm/regexp-macro-assembler-arm.cc b/src/arm/regexp-macro-assembler-arm.cc
index 24b6a9c..5ea7751 100644
--- a/src/arm/regexp-macro-assembler-arm.cc
+++ b/src/arm/regexp-macro-assembler-arm.cc
@@ -59,15 +59,19 @@
  *
  * Each call to a public method should retain this convention.
  * The stack will have the following structure:
+ *       - direct_call        (if 1, direct call from JavaScript code, if 0 call
+ *                             through the runtime system)
  *       - stack_area_base    (High end of the memory area to use as
  *                             backtracking stack)
- *       - at_start           (if 1, start at start of string, if 0, don't)
+ *       - at_start           (if 1, we are starting at the start of the
+ *                             string, otherwise 0)
+ *       - int* capture_array (int[num_saved_registers_], for output).
  *       --- sp when called ---
  *       - link address
  *       - backup of registers r4..r11
- *       - int* capture_array (int[num_saved_registers_], for output).
  *       - end of input       (Address of end of string)
  *       - start of input     (Address of first character in string)
+ *       - start index        (character index of start)
  *       --- frame pointer ----
  *       - void* input_string (location of a handle containing the string)
  *       - Offset of location before start of input (effectively character
@@ -85,11 +89,13 @@
  * The data up to the return address must be placed there by the calling
  * code, by calling the code entry as cast to a function with the signature:
  * int (*match)(String* input_string,
+ *              int start_index,
  *              Address start,
  *              Address end,
  *              int* capture_output_array,
  *              bool at_start,
- *              byte* stack_area_base)
+ *              byte* stack_area_base,
+ *              bool direct_call)
  * The call is performed by NativeRegExpMacroAssembler::Execute()
  * (in regexp-macro-assembler.cc).
  */
@@ -459,8 +465,6 @@
 
 
 bool RegExpMacroAssemblerARM::CheckSpecialCharacterClass(uc16 type,
-                                                         int cp_offset,
-                                                         bool check_offset,
                                                          Label* on_no_match) {
   // Range checks (c in min..max) are generally implemented by an unsigned
   // (c - min) <= (max - min) check
@@ -469,11 +473,6 @@
     // Match space-characters
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
-      if (check_offset) {
-        LoadCurrentCharacter(cp_offset, on_no_match);
-      } else {
-        LoadCurrentCharacterUnchecked(cp_offset, 1);
-      }
       Label success;
       __ cmp(current_character(), Operand(' '));
       __ b(eq, &success);
@@ -487,11 +486,6 @@
     return false;
   case 'S':
     // Match non-space characters.
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
       __ cmp(current_character(), Operand(' '));
@@ -504,33 +498,18 @@
     return false;
   case 'd':
     // Match ASCII digits ('0'..'9')
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     __ sub(r0, current_character(), Operand('0'));
     __ cmp(current_character(), Operand('9' - '0'));
     BranchOrBacktrack(hi, on_no_match);
     return true;
   case 'D':
     // Match non ASCII-digits
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     __ sub(r0, current_character(), Operand('0'));
     __ cmp(r0, Operand('9' - '0'));
     BranchOrBacktrack(ls, on_no_match);
     return true;
   case '.': {
     // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     __ eor(r0, current_character(), Operand(0x01));
     // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
     __ sub(r0, r0, Operand(0x0b));
@@ -546,13 +525,71 @@
     }
     return true;
   }
+  case 'n': {
+      // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+      __ eor(r0, current_character(), Operand(0x01));
+      // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+      __ sub(r0, r0, Operand(0x0b));
+      __ cmp(r0, Operand(0x0c - 0x0b));
+      if (mode_ == ASCII) {
+        BranchOrBacktrack(hi, on_no_match);
+      } else {
+        Label done;
+        __ b(ls, &done);
+        // Compare original value to 0x2028 and 0x2029, using the already
+        // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+        // 0x201d (0x2028 - 0x0b) or 0x201e.
+        __ sub(r0, r0, Operand(0x2028 - 0x0b));
+        __ cmp(r0, Operand(1));
+        BranchOrBacktrack(hi, on_no_match);
+        __ bind(&done);
+      }
+      return true;
+    }
+  case 'w': {
+    // Match word character (0-9, A-Z, a-z and _).
+    Label digits, done;
+    __ cmp(current_character(), Operand('9'));
+    __ b(ls, &digits);
+    __ cmp(current_character(), Operand('_'));
+    __ b(eq, &done);
+    __ orr(r0, current_character(), Operand(0x20));
+    __ sub(r0, r0, Operand('a'));
+    __ cmp(r0, Operand('z' - 'a'));
+    BranchOrBacktrack(hi, on_no_match);
+    __ jmp(&done);
+
+    __ bind(&digits);
+    __ cmp(current_character(), Operand('0'));
+    BranchOrBacktrack(lo, on_no_match);
+    __ bind(&done);
+
+    return true;
+  }
+  case 'W': {
+    // Match non-word character (not 0-9, A-Z, a-z and _).
+    Label digits, done;
+    __ cmp(current_character(), Operand('9'));
+    __ b(ls, &digits);
+    __ cmp(current_character(), Operand('_'));
+    BranchOrBacktrack(eq, on_no_match);
+    __ orr(r0, current_character(), Operand(0x20));
+    __ sub(r0, r0, Operand('a'));
+    __ cmp(r0, Operand('z' - 'a'));
+    BranchOrBacktrack(ls, on_no_match);
+    __ jmp(&done);
+
+    __ bind(&digits);
+    __ cmp(current_character(), Operand('0'));
+    BranchOrBacktrack(hs, on_no_match);
+    __ bind(&done);
+
+    return true;
+  }
   case '*':
     // Match any character.
-    if (check_offset) {
-      CheckPosition(cp_offset, on_no_match);
-    }
     return true;
-  // No custom implementation (yet): w, W, s(UC16), S(UC16).
+  // No custom implementation (yet): s(UC16), S(UC16).
   default:
     return false;
   }
diff --git a/src/arm/regexp-macro-assembler-arm.h b/src/arm/regexp-macro-assembler-arm.h
index f70bc05..4459859 100644
--- a/src/arm/regexp-macro-assembler-arm.h
+++ b/src/arm/regexp-macro-assembler-arm.h
@@ -80,8 +80,6 @@
   // the end of the string.
   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
   virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
                                           Label* on_no_match);
   virtual void Fail();
   virtual Handle<Object> GetCode(Handle<String> source);
@@ -127,6 +125,7 @@
   static const int kRegisterOutput = kReturnAddress + kPointerSize;
   static const int kAtStart = kRegisterOutput + kPointerSize;
   static const int kStackHighEnd = kAtStart + kPointerSize;
+  static const int kDirectCall = kStackHighEnd + kPointerSize;
 
   // Below the frame pointer.
   // Register parameters stored by setup code.
diff --git a/src/arm/simulator-arm.h b/src/arm/simulator-arm.h
index 3a4bb31..3ce5b7a 100644
--- a/src/arm/simulator-arm.h
+++ b/src/arm/simulator-arm.h
@@ -62,9 +62,9 @@
 
 
 // Call the generated regexp code directly. The entry function pointer should
-// expect seven int/pointer sized arguments and return an int.
-#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
-  entry(p0, p1, p2, p3, p4, p5, p6)
+// expect eight int/pointer sized arguments and return an int.
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6, p7) \
+  entry(p0, p1, p2, p3, p4, p5, p6, p7)
 
 #define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
   reinterpret_cast<TryCatch*>(try_catch_address)
@@ -79,9 +79,9 @@
       assembler::arm::Simulator::current()->Call(FUNCTION_ADDR(entry), 5, \
                                                  p0, p1, p2, p3, p4))
 
-#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6, p7) \
   assembler::arm::Simulator::current()->Call( \
-    FUNCTION_ADDR(entry), 7, p0, p1, p2, p3, p4, p5, p6)
+    FUNCTION_ADDR(entry), 8, p0, p1, p2, p3, p4, p5, p6, p7)
 
 #define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
   try_catch_address == NULL ? \
diff --git a/src/arm/virtual-frame-arm.cc b/src/arm/virtual-frame-arm.cc
index 132c8ae..a33ebd4 100644
--- a/src/arm/virtual-frame-arm.cc
+++ b/src/arm/virtual-frame-arm.cc
@@ -143,12 +143,25 @@
   if (count > 0) {
     Comment cmnt(masm(), "[ Allocate space for locals");
     Adjust(count);
-      // Initialize stack slots with 'undefined' value.
+    // Initialize stack slots with 'undefined' value.
     __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
-  }
-  __ LoadRoot(r2, Heap::kStackLimitRootIndex);
-  for (int i = 0; i < count; i++) {
-    __ push(ip);
+    __ LoadRoot(r2, Heap::kStackLimitRootIndex);
+    if (count < kLocalVarBound) {
+      // For less locals the unrolled loop is more compact.
+      for (int i = 0; i < count; i++) {
+        __ push(ip);
+      }
+    } else {
+      // For more locals a loop in generated code is more compact.
+      Label alloc_locals_loop;
+      __ mov(r1, Operand(count));
+      __ bind(&alloc_locals_loop);
+      __ push(ip);
+      __ sub(r1, r1, Operand(1), SetCC);
+      __ b(ne, &alloc_locals_loop);
+    }
+  } else {
+    __ LoadRoot(r2, Heap::kStackLimitRootIndex);
   }
   // Check the stack for overflow or a break request.
   // Put the lr setup instruction in the delay slot.  The kInstrSize is added
@@ -387,6 +400,13 @@
 }
 
 
+void VirtualFrame::EmitPushMultiple(int count, int src_regs) {
+  ASSERT(stack_pointer_ == element_count() - 1);
+  Adjust(count);
+  __ stm(db_w, sp, src_regs);
+}
+
+
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/arm/virtual-frame-arm.h b/src/arm/virtual-frame-arm.h
index d523000..b2f0eea 100644
--- a/src/arm/virtual-frame-arm.h
+++ b/src/arm/virtual-frame-arm.h
@@ -180,6 +180,9 @@
   // shared return site.  Emits code for spills.
   void PrepareForReturn();
 
+  // Number of local variables after when we use a loop for allocating.
+  static const int kLocalVarBound = 5;
+
   // Allocate and initialize the frame-allocated locals.
   void AllocateStackSlots();
 
@@ -346,6 +349,11 @@
   // corresponding push instruction.
   void EmitPush(Register reg);
 
+  // Push multiple registers on the stack and the virtual frame
+  // Register are selected by setting bit in src_regs and
+  // are pushed in decreasing order: r15 .. r0.
+  void EmitPushMultiple(int count, int src_regs);
+
   // Push an element on the virtual frame.
   void Push(Register reg);
   void Push(Handle<Object> value);
diff --git a/src/array.js b/src/array.js
index 20d884e..c3ab179 100644
--- a/src/array.js
+++ b/src/array.js
@@ -70,19 +70,22 @@
 // Optimized for sparse arrays if separator is ''.
 function SparseJoin(array, len, convert) {
   var keys = GetSortedArrayKeys(array, %GetArrayKeys(array, len));
-  var builder = new StringBuilder();
   var last_key = -1;
   var keys_length = keys.length;
+
+  var elements = new $Array(keys_length);
+  var elements_length = 0;
+
   for (var i = 0; i < keys_length; i++) {
     var key = keys[i];
     if (key != last_key) {
       var e = array[key];
-      if (typeof(e) !== 'string') e = convert(e);
-      builder.add(e);
+      if (!IS_STRING(e)) e = convert(e);
+      elements[elements_length++] = e;
       last_key = key;
     }
   }
-  return builder.generate();
+  return %StringBuilderConcat(elements, elements_length, '');
 }
 
 
@@ -107,7 +110,7 @@
 
   // Attempt to convert the elements.
   try {
-    if (UseSparseVariant(array, length, is_array) && separator === '') {
+    if (UseSparseVariant(array, length, is_array) && (separator.length == 0)) {
       return SparseJoin(array, length, convert);
     }
 
@@ -115,39 +118,37 @@
     if (length == 1) {
       var e = array[0];
       if (!IS_UNDEFINED(e) || (0 in array)) {
-        if (typeof(e) === 'string') return e;
+        if (IS_STRING(e)) return e;
         return convert(e);
       }
     }
 
-    var builder = new StringBuilder();
+    // Construct an array for the elements.
+    var elements;
+    var elements_length = 0;
 
     // We pull the empty separator check outside the loop for speed!
     if (separator.length == 0) {
+      elements = new $Array(length);
       for (var i = 0; i < length; i++) {
         var e = array[i];
         if (!IS_UNDEFINED(e) || (i in array)) {
-          if (typeof(e) !== 'string') e = convert(e);
-          if (e.length > 0) {
-            var elements = builder.elements;
-            elements[elements.length] = e;
-          }
+          if (!IS_STRING(e)) e = convert(e);
+          elements[elements_length++] = e;
         }
       }
     } else {
+      elements = new $Array(length << 1);
       for (var i = 0; i < length; i++) {
         var e = array[i];
-        if (i != 0) builder.add(separator);
+        if (i != 0) elements[elements_length++] = separator;
         if (!IS_UNDEFINED(e) || (i in array)) {
-          if (typeof(e) !== 'string') e = convert(e);
-          if (e.length > 0) {
-            var elements = builder.elements;
-            elements[elements.length] = e;
-          }
+          if (!IS_STRING(e)) e = convert(e);
+          elements[elements_length++] = e;
         }
       }
     }
-    return builder.generate();
+    return %StringBuilderConcat(elements, elements_length, '');
   } finally {
     // Make sure to pop the visited array no matter what happens.
     if (is_array) visited_arrays.pop();
@@ -156,16 +157,15 @@
 
 
 function ConvertToString(e) {
-  if (typeof(e) === 'string') return e;
   if (e == null) return '';
   else return ToString(e);
 }
 
 
 function ConvertToLocaleString(e) {
-  if (typeof(e) === 'string') return e;
-  if (e == null) return '';
-  else {
+  if (e == null) {
+    return '';
+  } else {
     // e_obj's toLocaleString might be overwritten, check if it is a function.
     // Call ToString if toLocaleString is not a function.
     // See issue 877615.
@@ -359,16 +359,20 @@
 
 
 function ArrayJoin(separator) {
-  if (IS_UNDEFINED(separator)) separator = ',';
-  else separator = ToString(separator);
-  return Join(this, ToUint32(this.length), separator, ConvertToString);
+  if (IS_UNDEFINED(separator)) {
+    separator = ',';
+  } else if (!IS_STRING(separator)) {
+    separator = ToString(separator);
+  }
+  var length = TO_UINT32(this.length);
+  return Join(this, length, separator, ConvertToString);
 }
 
 
 // Removes the last element from the array and returns it. See
 // ECMA-262, section 15.4.4.6.
 function ArrayPop() {
-  var n = ToUint32(this.length);
+  var n = TO_UINT32(this.length);
   if (n == 0) {
     this.length = n;
     return;
@@ -384,7 +388,7 @@
 // Appends the arguments to the end of the array and returns the new
 // length of the array. See ECMA-262, section 15.4.4.7.
 function ArrayPush() {
-  var n = ToUint32(this.length);
+  var n = TO_UINT32(this.length);
   var m = %_ArgumentsLength();
   for (var i = 0; i < m; i++) {
     this[i+n] = %_Arguments(i);
@@ -452,7 +456,7 @@
 
 
 function ArrayReverse() {
-  var j = ToUint32(this.length) - 1;
+  var j = TO_UINT32(this.length) - 1;
 
   if (UseSparseVariant(this, j, IS_ARRAY(this))) {
     SparseReverse(this, j+1);
@@ -483,7 +487,7 @@
 
 
 function ArrayShift() {
-  var len = ToUint32(this.length);
+  var len = TO_UINT32(this.length);
 
   if (len === 0) {
     this.length = 0;
@@ -504,7 +508,7 @@
 
 
 function ArrayUnshift(arg1) {  // length == 1
-  var len = ToUint32(this.length);
+  var len = TO_UINT32(this.length);
   var num_arguments = %_ArgumentsLength();
 
   if (IS_ARRAY(this))
@@ -523,7 +527,7 @@
 
 
 function ArraySlice(start, end) {
-  var len = ToUint32(this.length);
+  var len = TO_UINT32(this.length);
   var start_i = TO_INTEGER(start);
   var end_i = len;
 
@@ -568,7 +572,7 @@
   // compatibility.
   if (num_arguments == 0) return;
 
-  var len = ToUint32(this.length);
+  var len = TO_UINT32(this.length);
   var start_i = TO_INTEGER(start);
 
   if (start_i < 0) {
@@ -850,7 +854,7 @@
     return first_undefined;
   }
 
-  length = ToUint32(this.length);
+  length = TO_UINT32(this.length);
   if (length < 2) return this;
 
   var is_array = IS_ARRAY(this);
@@ -915,7 +919,7 @@
   }
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping.
-  var length = this.length;
+  var length =  TO_UINT32(this.length);
   for (var i = 0; i < length; i++) {
     var current = this[i];
     if (!IS_UNDEFINED(current) || i in this) {
@@ -933,7 +937,7 @@
   }
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping.
-  var length = this.length;
+  var length = TO_UINT32(this.length);
   for (var i = 0; i < length; i++) {
     var current = this[i];
     if (!IS_UNDEFINED(current) || i in this) {
@@ -950,25 +954,23 @@
   }
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping.
-  var length = this.length;
+  var length = TO_UINT32(this.length);
   for (var i = 0; i < length; i++) {
     var current = this[i];
     if (!IS_UNDEFINED(current) || i in this) {
       if (!f.call(receiver, current, i, this)) return false;
     }
   }
-
   return true;
 }
 
-
 function ArrayMap(f, receiver) {
   if (!IS_FUNCTION(f)) {
     throw MakeTypeError('called_non_callable', [ f ]);
   }
   // Pull out the length so that modifications to the length in the
   // loop will not affect the looping.
-  var length = this.length;
+  var length = TO_UINT32(this.length);
   var result = new $Array(length);
   for (var i = 0; i < length; i++) {
     var current = this[i];
diff --git a/src/assembler.cc b/src/assembler.cc
index 2d16250..a736fb1 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -674,6 +674,19 @@
       FUNCTION_ADDR(NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16)));
 }
 
+
+ExternalReference ExternalReference::address_of_static_offsets_vector() {
+  return ExternalReference(OffsetsVector::static_offsets_vector_address());
+}
+
+ExternalReference ExternalReference::address_of_regexp_stack_memory_address() {
+  return ExternalReference(RegExpStack::memory_address());
+}
+
+ExternalReference ExternalReference::address_of_regexp_stack_memory_size() {
+  return ExternalReference(RegExpStack::memory_size_address());
+}
+
 #endif
 
 
diff --git a/src/assembler.h b/src/assembler.h
index 87cde9b..e5efe89 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -420,6 +420,11 @@
   // Static variable RegExpStack::limit_address()
   static ExternalReference address_of_regexp_stack_limit();
 
+  // Static variables for RegExp.
+  static ExternalReference address_of_static_offsets_vector();
+  static ExternalReference address_of_regexp_stack_memory_address();
+  static ExternalReference address_of_regexp_stack_memory_size();
+
   // Static variable Heap::NewSpaceStart()
   static ExternalReference new_space_start();
   static ExternalReference heap_always_allocate_scope_depth();
diff --git a/src/ast.cc b/src/ast.cc
index 90b5ed6..4edcf6d 100644
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -433,7 +433,7 @@
   } else {
     stream()->Add("%i ", that->max());
   }
-  stream()->Add(that->is_greedy() ? "g " : "n ");
+  stream()->Add(that->is_greedy() ? "g " : that->is_possessive() ? "p " : "n ");
   that->body()->Accept(this, data);
   stream()->Add(")");
   return NULL;
diff --git a/src/ast.h b/src/ast.h
index 195fc14..3961cb8 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -187,6 +187,11 @@
   virtual bool IsValidJSON() { return false; }
   virtual bool IsValidLeftHandSide() { return false; }
 
+  // Symbols that cannot be parsed as array indices are considered property
+  // names.  We do not treat symbols that can be array indexes as property
+  // names because [] for string objects is handled only by keyed ICs.
+  virtual bool IsPropertyName() { return false; }
+
   // Mark the expression as being compiled as an expression
   // statement. This is used to transform postfix increments to
   // (faster) prefix increments.
@@ -642,21 +647,20 @@
 class TryCatchStatement: public TryStatement {
  public:
   TryCatchStatement(Block* try_block,
-                    Expression* catch_var,
+                    VariableProxy* catch_var,
                     Block* catch_block)
       : TryStatement(try_block),
         catch_var_(catch_var),
         catch_block_(catch_block) {
-    ASSERT(catch_var->AsVariableProxy() != NULL);
   }
 
   virtual void Accept(AstVisitor* v);
 
-  Expression* catch_var() const  { return catch_var_; }
+  VariableProxy* catch_var() const  { return catch_var_; }
   Block* catch_block() const  { return catch_block_; }
 
  private:
-  Expression* catch_var_;
+  VariableProxy* catch_var_;
   Block* catch_block_;
 };
 
@@ -707,6 +711,14 @@
 
   virtual bool IsValidJSON() { return true; }
 
+  virtual bool IsPropertyName() {
+    if (handle_->IsSymbol()) {
+      uint32_t ignored;
+      return !String::cast(*handle_)->AsArrayIndex(&ignored);
+    }
+    return false;
+  }
+
   // Identity testers.
   bool IsNull() const { return handle_.is_identical_to(Factory::null_value()); }
   bool IsTrue() const { return handle_.is_identical_to(Factory::true_value()); }
@@ -827,24 +839,24 @@
 // for minimizing the work when constructing it at runtime.
 class ArrayLiteral: public MaterializedLiteral {
  public:
-  ArrayLiteral(Handle<FixedArray> literals,
+  ArrayLiteral(Handle<FixedArray> constant_elements,
                ZoneList<Expression*>* values,
                int literal_index,
                bool is_simple,
                int depth)
       : MaterializedLiteral(literal_index, is_simple, depth),
-        literals_(literals),
+        constant_elements_(constant_elements),
         values_(values) {}
 
   virtual void Accept(AstVisitor* v);
   virtual ArrayLiteral* AsArrayLiteral() { return this; }
   virtual bool IsValidJSON();
 
-  Handle<FixedArray> literals() const { return literals_; }
+  Handle<FixedArray> constant_elements() const { return constant_elements_; }
   ZoneList<Expression*>* values() const { return values_; }
 
  private:
-  Handle<FixedArray> literals_;
+  Handle<FixedArray> constant_elements_;
   ZoneList<Expression*>* values_;
 };
 
@@ -1526,6 +1538,7 @@
     standard_set_type_ = special_set_type;
   }
   bool is_standard() { return standard_set_type_ != 0; }
+  void Canonicalize();
  private:
   ZoneList<CharacterRange>* ranges_;
   // If non-zero, the value represents a standard set (e.g., all whitespace
@@ -1619,12 +1632,13 @@
 
 class RegExpQuantifier: public RegExpTree {
  public:
-  RegExpQuantifier(int min, int max, bool is_greedy, RegExpTree* body)
-      : min_(min),
+  enum Type { GREEDY, NON_GREEDY, POSSESSIVE };
+  RegExpQuantifier(int min, int max, Type type, RegExpTree* body)
+      : body_(body),
+        min_(min),
         max_(max),
-        is_greedy_(is_greedy),
-        body_(body),
-        min_match_(min * body->min_match()) {
+        min_match_(min * body->min_match()),
+        type_(type) {
     if (max > 0 && body->max_match() > kInfinity / max) {
       max_match_ = kInfinity;
     } else {
@@ -1648,15 +1662,17 @@
   virtual int max_match() { return max_match_; }
   int min() { return min_; }
   int max() { return max_; }
-  bool is_greedy() { return is_greedy_; }
+  bool is_possessive() { return type_ == POSSESSIVE; }
+  bool is_non_greedy() { return type_ == NON_GREEDY; }
+  bool is_greedy() { return type_ == GREEDY; }
   RegExpTree* body() { return body_; }
  private:
+  RegExpTree* body_;
   int min_;
   int max_;
-  bool is_greedy_;
-  RegExpTree* body_;
   int min_match_;
   int max_match_;
+  Type type_;
 };
 
 
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 6ae3125..9eacf57 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -992,6 +992,7 @@
   INSTALL_NATIVE(JSFunction, "ToUint32", to_uint32_fun);
   INSTALL_NATIVE(JSFunction, "ToInt32", to_int32_fun);
   INSTALL_NATIVE(JSFunction, "ToBoolean", to_boolean_fun);
+  INSTALL_NATIVE(JSFunction, "GlobalEval", global_eval_fun);
   INSTALL_NATIVE(JSFunction, "Instantiate", instantiate_fun);
   INSTALL_NATIVE(JSFunction, "ConfigureTemplateInstance",
                  configure_instance_fun);
diff --git a/src/builtins.cc b/src/builtins.cc
index b66635c..aa680d7 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -544,6 +544,11 @@
 }
 
 
+static void Generate_KeyedLoadIC_String(MacroAssembler* masm) {
+  KeyedLoadIC::GenerateString(masm);
+}
+
+
 static void Generate_KeyedLoadIC_ExternalByteArray(MacroAssembler* masm) {
   KeyedLoadIC::GenerateExternalArray(masm, kExternalByteArray);
 }
diff --git a/src/builtins.h b/src/builtins.h
index bc32c49..f0ceab6 100644
--- a/src/builtins.h
+++ b/src/builtins.h
@@ -74,6 +74,7 @@
   V(KeyedLoadIC_Initialize,     KEYED_LOAD_IC, UNINITIALIZED)             \
   V(KeyedLoadIC_PreMonomorphic, KEYED_LOAD_IC, PREMONOMORPHIC)            \
   V(KeyedLoadIC_Generic,        KEYED_LOAD_IC, MEGAMORPHIC)               \
+  V(KeyedLoadIC_String,         KEYED_LOAD_IC, MEGAMORPHIC)               \
   V(KeyedLoadIC_ExternalByteArray,          KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalUnsignedByteArray,  KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalShortArray,         KEYED_LOAD_IC, MEGAMORPHIC)   \
@@ -147,7 +148,8 @@
   V(STRING_ADD_LEFT, 1)                  \
   V(STRING_ADD_RIGHT, 1)                 \
   V(APPLY_PREPARE, 1)                    \
-  V(APPLY_OVERFLOW, 1)
+  V(APPLY_OVERFLOW, 1)                   \
+  V(STRING_CHAR_AT, 1)
 
 
 class ObjectVisitor;
diff --git a/src/code-stubs.h b/src/code-stubs.h
index fee92b9..052c1ca 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -37,6 +37,8 @@
   V(CallFunction)                        \
   V(GenericBinaryOp)                     \
   V(StringAdd)                           \
+  V(SubString)                           \
+  V(StringCompare)                       \
   V(SmiOp)                               \
   V(Compare)                             \
   V(RecordWrite)                         \
@@ -46,12 +48,13 @@
   V(FastNewClosure)                      \
   V(FastNewContext)                      \
   V(FastCloneShallowArray)               \
-  V(UnarySub)                            \
+  V(GenericUnaryOp)                      \
   V(RevertToNumber)                      \
   V(ToBoolean)                           \
   V(Instanceof)                          \
   V(CounterOp)                           \
   V(ArgumentsAccess)                     \
+  V(RegExpExec)                          \
   V(Runtime)                             \
   V(CEntry)                              \
   V(JSEntry)
diff --git a/src/codegen.cc b/src/codegen.cc
index 26e8d7d..fd7e0e8 100644
--- a/src/codegen.cc
+++ b/src/codegen.cc
@@ -342,11 +342,12 @@
   {&CodeGenerator::GenerateObjectEquals, "_ObjectEquals"},
   {&CodeGenerator::GenerateLog, "_Log"},
   {&CodeGenerator::GenerateRandomPositiveSmi, "_RandomPositiveSmi"},
-  {&CodeGenerator::GenerateMathSin, "_Math_sin"},
-  {&CodeGenerator::GenerateMathCos, "_Math_cos"},
   {&CodeGenerator::GenerateIsObject, "_IsObject"},
   {&CodeGenerator::GenerateIsFunction, "_IsFunction"},
   {&CodeGenerator::GenerateStringAdd, "_StringAdd"},
+  {&CodeGenerator::GenerateSubString, "_SubString"},
+  {&CodeGenerator::GenerateStringCompare, "_StringCompare"},
+  {&CodeGenerator::GenerateRegExpExec, "_RegExpExec"},
 };
 
 
@@ -450,6 +451,23 @@
 }
 
 
+const char* GenericUnaryOpStub::GetName() {
+  switch (op_) {
+    case Token::SUB:
+      return overwrite_
+          ? "GenericUnaryOpStub_SUB_Overwrite"
+          : "GenericUnaryOpStub_SUB_Alloc";
+    case Token::BIT_NOT:
+      return overwrite_
+          ? "GenericUnaryOpStub_BIT_NOT_Overwrite"
+          : "GenericUnaryOpStub_BIT_NOT_Alloc";
+    default:
+      UNREACHABLE();
+      return "<unknown>";
+  }
+}
+
+
 void RuntimeStub::Generate(MacroAssembler* masm) {
   Runtime::Function* f = Runtime::FunctionForId(id_);
   masm->TailCallRuntime(ExternalReference(f),
diff --git a/src/codegen.h b/src/codegen.h
index b3cf51e..2247c5c 100644
--- a/src/codegen.h
+++ b/src/codegen.h
@@ -294,30 +294,53 @@
 };
 
 
-class UnarySubStub : public CodeStub {
+class GenericUnaryOpStub : public CodeStub {
  public:
-  explicit UnarySubStub(bool overwrite)
-      : overwrite_(overwrite) { }
+  GenericUnaryOpStub(Token::Value op, bool overwrite)
+      : op_(op), overwrite_(overwrite) { }
 
  private:
+  Token::Value op_;
   bool overwrite_;
-  Major MajorKey() { return UnarySub; }
-  int MinorKey() { return overwrite_ ? 1 : 0; }
+
+  class OverwriteField: public BitField<int, 0, 1> {};
+  class OpField: public BitField<Token::Value, 1, kMinorBits - 1> {};
+
+  Major MajorKey() { return GenericUnaryOp; }
+  int MinorKey() {
+    return OpField::encode(op_) | OverwriteField::encode(overwrite_);
+  }
+
   void Generate(MacroAssembler* masm);
 
-  const char* GetName() { return "UnarySubStub"; }
+  const char* GetName();
+};
+
+
+enum NaNInformation {
+  kBothCouldBeNaN,
+  kCantBothBeNaN
 };
 
 
 class CompareStub: public CodeStub {
  public:
-  CompareStub(Condition cc, bool strict) : cc_(cc), strict_(strict) { }
+  CompareStub(Condition cc,
+              bool strict,
+              NaNInformation nan_info = kBothCouldBeNaN) :
+      cc_(cc), strict_(strict), never_nan_nan_(nan_info == kCantBothBeNaN) { }
 
   void Generate(MacroAssembler* masm);
 
  private:
   Condition cc_;
   bool strict_;
+  // Only used for 'equal' comparisons.  Tells the stub that we already know
+  // that at least one side of the comparison is not NaN.  This allows the
+  // stub to use object identity in the positive case.  We ignore it when
+  // generating the minor key for other comparisons to avoid creating more
+  // stubs.
+  bool never_nan_nan_;
 
   Major MajorKey() { return Compare; }
 
@@ -329,6 +352,9 @@
                          Register object,
                          Register scratch);
 
+  // Unfortunately you have to run without snapshots to see most of these
+  // names in the profile since most compare stubs end up in the snapshot.
+  const char* GetName();
 #ifdef DEBUG
   void Print() {
     PrintF("CompareStub (cc %d), (strict %s)\n",
@@ -470,6 +496,26 @@
 };
 
 
+class RegExpExecStub: public CodeStub {
+ public:
+  RegExpExecStub() { }
+
+ private:
+  Major MajorKey() { return RegExpExec; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+
+  const char* GetName() { return "RegExpExecStub"; }
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("RegExpExecStub\n");
+  }
+#endif
+};
+
+
 }  // namespace internal
 }  // namespace v8
 
diff --git a/src/compiler.cc b/src/compiler.cc
index 03771d9..420b809 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -538,7 +538,7 @@
     LOG(CodeCreateEvent(Logger::FUNCTION_TAG, *code, *literal->name()));
 
 #ifdef ENABLE_OPROFILE_AGENT
-    OProfileAgent::CreateNativeCodeRegion(*node->name(),
+    OProfileAgent::CreateNativeCodeRegion(*literal->name(),
                                           code->instruction_start(),
                                           code->instruction_size());
 #endif
@@ -649,12 +649,6 @@
 void CodeGenSelector::VisitDeclaration(Declaration* decl) {
   Property* prop = decl->proxy()->AsProperty();
   if (prop != NULL) {
-    // Property rewrites are shared, ensure we are not changing its
-    // expression context state.
-    ASSERT(prop->obj()->context() == Expression::kUninitialized ||
-           prop->obj()->context() == Expression::kValue);
-    ASSERT(prop->key()->context() == Expression::kUninitialized ||
-           prop->key()->context() == Expression::kValue);
     ProcessExpression(prop->obj(), Expression::kValue);
     ProcessExpression(prop->key(), Expression::kValue);
   }
@@ -746,7 +740,9 @@
 
 
 void CodeGenSelector::VisitTryCatchStatement(TryCatchStatement* stmt) {
-  BAILOUT("TryCatchStatement");
+  Visit(stmt->try_block());
+  CHECK_BAILOUT;
+  Visit(stmt->catch_block());
 }
 
 
@@ -876,7 +872,9 @@
 
 
 void CodeGenSelector::VisitCatchExtensionObject(CatchExtensionObject* expr) {
-  BAILOUT("CatchExtensionObject");
+  ProcessExpression(expr->key(), Expression::kValue);
+  CHECK_BAILOUT;
+  ProcessExpression(expr->value(), Expression::kValue);
 }
 
 
@@ -890,6 +888,9 @@
   Property* prop = expr->target()->AsProperty();
   ASSERT(var == NULL || prop == NULL);
   if (var != NULL) {
+    if (var->mode() == Variable::CONST) {
+      BAILOUT("Assignment to const");
+    }
     // All global variables are supported.
     if (!var->is_global()) {
       ASSERT(var->slot() != NULL);
@@ -899,20 +900,12 @@
       }
     }
   } else if (prop != NULL) {
-    ASSERT(prop->obj()->context() == Expression::kUninitialized ||
-           prop->obj()->context() == Expression::kValue);
     ProcessExpression(prop->obj(), Expression::kValue);
     CHECK_BAILOUT;
     // We will only visit the key during code generation for keyed property
     // stores.  Leave its expression context uninitialized for named
     // property stores.
-    Literal* lit = prop->key()->AsLiteral();
-    uint32_t ignored;
-    if (lit == NULL ||
-        !lit->handle()->IsSymbol() ||
-        String::cast(*(lit->handle()))->AsArrayIndex(&ignored)) {
-      ASSERT(prop->key()->context() == Expression::kUninitialized ||
-             prop->key()->context() == Expression::kValue);
+    if (!prop->key()->IsPropertyName()) {
       ProcessExpression(prop->key(), Expression::kValue);
       CHECK_BAILOUT;
     }
@@ -926,7 +919,7 @@
 
 
 void CodeGenSelector::VisitThrow(Throw* expr) {
-  BAILOUT("Throw");
+  ProcessExpression(expr->exception(), Expression::kValue);
 }
 
 
@@ -1018,11 +1011,32 @@
 
 
 void CodeGenSelector::VisitCountOperation(CountOperation* expr) {
-  // We support postfix count operations on global variables.
-  if (expr->is_prefix()) BAILOUT("Prefix CountOperation");
   Variable* var = expr->expression()->AsVariableProxy()->AsVariable();
-  if (var == NULL || !var->is_global()) BAILOUT("non-global postincrement");
-  ProcessExpression(expr->expression(), Expression::kValue);
+  Property* prop = expr->expression()->AsProperty();
+  ASSERT(var == NULL || prop == NULL);
+  if (var != NULL) {
+    // All global variables are supported.
+    if (!var->is_global()) {
+      ASSERT(var->slot() != NULL);
+      Slot::Type type = var->slot()->type();
+      if (type == Slot::LOOKUP) {
+        BAILOUT("CountOperation with lookup slot");
+      }
+    }
+  } else if (prop != NULL) {
+    ProcessExpression(prop->obj(), Expression::kValue);
+    CHECK_BAILOUT;
+    // We will only visit the key during code generation for keyed property
+    // stores.  Leave its expression context uninitialized for named
+    // property stores.
+    if (!prop->key()->IsPropertyName()) {
+      ProcessExpression(prop->key(), Expression::kValue);
+      CHECK_BAILOUT;
+    }
+  } else {
+    // This is a throw reference error.
+    BAILOUT("CountOperation non-variable/non-property expression");
+  }
 }
 
 
diff --git a/src/contexts.h b/src/contexts.h
index bdfc40b..66c1575 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -77,6 +77,7 @@
   V(TO_UINT32_FUN_INDEX, JSFunction, to_uint32_fun) \
   V(TO_INT32_FUN_INDEX, JSFunction, to_int32_fun) \
   V(TO_BOOLEAN_FUN_INDEX, JSFunction, to_boolean_fun) \
+  V(GLOBAL_EVAL_FUN_INDEX, JSFunction, global_eval_fun) \
   V(INSTANTIATE_FUN_INDEX, JSFunction, instantiate_fun) \
   V(CONFIGURE_INSTANCE_FUN_INDEX, JSFunction, configure_instance_fun) \
   V(FUNCTION_MAP_INDEX, Map, function_map) \
@@ -202,6 +203,7 @@
     TO_UINT32_FUN_INDEX,
     TO_INT32_FUN_INDEX,
     TO_BOOLEAN_FUN_INDEX,
+    GLOBAL_EVAL_FUN_INDEX,
     INSTANTIATE_FUN_INDEX,
     CONFIGURE_INSTANCE_FUN_INDEX,
     SPECIAL_FUNCTION_TABLE_INDEX,
diff --git a/src/date-delay.js b/src/date-delay.js
index 0778dc9..7d8f458 100644
--- a/src/date-delay.js
+++ b/src/date-delay.js
@@ -45,12 +45,6 @@
   throw new $TypeError('this is not a Date object.');
 }
 
-// ECMA 262 - 15.9.1.2
-function Day(time) {
-  return FLOOR(time / msPerDay);
-}
-
-
 // ECMA 262 - 5.2
 function Modulo(value, remainder) {
   var mod = value % remainder;
@@ -86,30 +80,13 @@
 }
 
 
-function YearFromTime(time) {
-  return FromJulianDay(Day(time) + kDayZeroInJulianDay).year;
-}
-
-
 function InLeapYear(time) {
-  return DaysInYear(YearFromTime(time)) == 366 ? 1 : 0;
-}
-
-
-// ECMA 262 - 15.9.1.4
-function MonthFromTime(time) {
-  return FromJulianDay(Day(time) + kDayZeroInJulianDay).month;
+  return DaysInYear(YEAR_FROM_TIME(time)) == 366 ? 1 : 0;
 }
 
 
 function DayWithinYear(time) {
-  return Day(time) - DayFromYear(YearFromTime(time));
-}
-
-
-// ECMA 262 - 15.9.1.5
-function DateFromTime(time) {
-  return FromJulianDay(Day(time) + kDayZeroInJulianDay).date;
+  return DAY(time) - DayFromYear(YEAR_FROM_TIME(time));
 }
 
 
@@ -136,7 +113,7 @@
   // we must do this, but for compatibility with other browsers, we use
   // the actual year if it is in the range 1970..2037
   if (t >= 0 && t <= 2.1e12) return t;
-  var day = MakeDay(EquivalentYear(YearFromTime(t)), MonthFromTime(t), DateFromTime(t));
+  var day = MakeDay(EquivalentYear(YEAR_FROM_TIME(t)), MONTH_FROM_TIME(t), DATE_FROM_TIME(t));
   return TimeClip(MakeDate(day, TimeWithinDay(t)));
 }
 
@@ -232,7 +209,7 @@
 
 
 function WeekDay(time) {
-  return Modulo(Day(time) + 4, 7);
+  return Modulo(DAY(time) + 4, 7);
 }
 
 var local_time_offset = %DateLocalTimeOffset();
@@ -243,7 +220,14 @@
 }
 
 function LocalTimeNoCheck(time) {
-  return time + local_time_offset + DaylightSavingsOffset(time);
+  // Inline the DST offset cache checks for speed.
+  var cache = DST_offset_cache;
+  if (cache.start <= time && time <= cache.end) {
+    var dst_offset = cache.offset;
+  } else {
+    var dst_offset = DaylightSavingsOffset(time);
+  }
+  return time + local_time_offset + dst_offset;
 }
 
 
@@ -254,27 +238,6 @@
 }
 
 
-// ECMA 262 - 15.9.1.10
-function HourFromTime(time) {
-  return Modulo(FLOOR(time / msPerHour), HoursPerDay);
-}
-
-
-function MinFromTime(time) {
-  return Modulo(FLOOR(time / msPerMinute), MinutesPerHour);
-}
-
-
-function SecFromTime(time) {
-  return Modulo(FLOOR(time / msPerSecond), SecondsPerMinute);
-}
-
-
-function msFromTime(time) {
-  return Modulo(time, msPerSecond);
-}
-
-
 // ECMA 262 - 15.9.1.11
 function MakeTime(hour, min, sec, ms) {
   if (!$isFinite(hour)) return $NaN;
@@ -468,7 +431,7 @@
         value = DateParse(year);
         if (!NUMBER_IS_NAN(value)) {
           cache.time = value;
-          cache.year = YearFromTime(LocalTimeNoCheck(value));
+          cache.year = YEAR_FROM_TIME(LocalTimeNoCheck(value));
           cache.string = year;
         }
       }
@@ -508,60 +471,59 @@
   return DATE_VALUE(aDate);
 }
 
-
 function GetMillisecondsFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return msFromTime(LocalTimeNoCheck(t));
+  return MS_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCMillisecondsFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return msFromTime(t);
+  return MS_FROM_TIME(t);
 }
 
 
 function GetSecondsFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return SecFromTime(LocalTimeNoCheck(t));
+  return SEC_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCSecondsFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return SecFromTime(t);
+  return SEC_FROM_TIME(t);
 }
 
 
 function GetMinutesFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return MinFromTime(LocalTimeNoCheck(t));
+  return MIN_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCMinutesFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return MinFromTime(t);
+  return MIN_FROM_TIME(t);
 }
 
 
 function GetHoursFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return HourFromTime(LocalTimeNoCheck(t));
+  return HOUR_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCHoursFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return HourFromTime(t);
+  return HOUR_FROM_TIME(t);
 }
 
 
@@ -570,42 +532,42 @@
   if (NUMBER_IS_NAN(t)) return t;
   var cache = Date_cache;
   if (cache.time === t) return cache.year;
-  return YearFromTime(LocalTimeNoCheck(t));
+  return YEAR_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCFullYearFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return YearFromTime(t);
+  return YEAR_FROM_TIME(t);
 }
 
 
 function GetMonthFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return MonthFromTime(LocalTimeNoCheck(t));
+  return MONTH_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCMonthFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return MonthFromTime(t);
+  return MONTH_FROM_TIME(t);
 }
 
 
 function GetDateFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return DateFromTime(LocalTimeNoCheck(t));
+  return DATE_FROM_TIME(LocalTimeNoCheck(t));
 }
 
 
 function GetUTCDateFrom(aDate) {
   var t = DATE_VALUE(aDate);
   if (NUMBER_IS_NAN(t)) return t;
-  return DateFromTime(t);
+  return DATE_FROM_TIME(t);
 }
 
 
@@ -622,7 +584,7 @@
 
 
 function DateString(time) {
-  var YMD = FromJulianDay(Day(time) + kDayZeroInJulianDay);
+  var YMD = FromJulianDay(DAY(time) + kDayZeroInJulianDay);
   return WeekDays[WeekDay(time)] + ' '
       + Months[YMD.month] + ' '
       + TwoDigitString(YMD.date) + ' '
@@ -635,7 +597,7 @@
 
 
 function LongDateString(time) {
-  var YMD = FromJulianDay(Day(time) + kDayZeroInJulianDay);
+  var YMD = FromJulianDay(DAY(time) + kDayZeroInJulianDay);
   return LongWeekDays[WeekDay(time)] + ', '
       + LongMonths[YMD.month] + ' '
       + TwoDigitString(YMD.date) + ', '
@@ -644,9 +606,9 @@
 
 
 function TimeString(time) {
-  return TwoDigitString(HourFromTime(time)) + ':'
-      + TwoDigitString(MinFromTime(time)) + ':'
-      + TwoDigitString(SecFromTime(time));
+  return TwoDigitString(HOUR_FROM_TIME(time)) + ':'
+      + TwoDigitString(MIN_FROM_TIME(time)) + ':'
+      + TwoDigitString(SEC_FROM_TIME(time));
 }
 
 
@@ -892,8 +854,8 @@
 function DateSetMilliseconds(ms) {
   var t = LocalTime(DATE_VALUE(this));
   ms = ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), MinFromTime(t), SecFromTime(t), ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(Day(t), time))));
+  var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), SEC_FROM_TIME(t), ms);
+  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -901,8 +863,8 @@
 function DateSetUTCMilliseconds(ms) {
   var t = DATE_VALUE(this);
   ms = ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), MinFromTime(t), SecFromTime(t), ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(Day(t), time)));
+  var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), SEC_FROM_TIME(t), ms);
+  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -911,8 +873,8 @@
   var t = LocalTime(DATE_VALUE(this));
   sec = ToNumber(sec);
   ms = %_ArgumentsLength() < 2 ? GetMillisecondsFrom(this) : ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), MinFromTime(t), sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(Day(t), time))));
+  var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), sec, ms);
+  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -921,8 +883,8 @@
   var t = DATE_VALUE(this);
   sec = ToNumber(sec);
   ms = %_ArgumentsLength() < 2 ? GetUTCMillisecondsFrom(this) : ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), MinFromTime(t), sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(Day(t), time)));
+  var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), sec, ms);
+  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -933,8 +895,8 @@
   var argc = %_ArgumentsLength();
   sec = argc < 2 ? GetSecondsFrom(this) : ToNumber(sec);
   ms = argc < 3 ? GetMillisecondsFrom(this) : ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), min, sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(Day(t), time))));
+  var time = MakeTime(HOUR_FROM_TIME(t), min, sec, ms);
+  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -945,8 +907,8 @@
   var argc = %_ArgumentsLength();
   sec = argc < 2 ? GetUTCSecondsFrom(this) : ToNumber(sec);
   ms = argc < 3 ? GetUTCMillisecondsFrom(this) : ToNumber(ms);
-  var time = MakeTime(HourFromTime(t), min, sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(Day(t), time)));
+  var time = MakeTime(HOUR_FROM_TIME(t), min, sec, ms);
+  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -959,7 +921,7 @@
   sec = argc < 3 ? GetSecondsFrom(this) : ToNumber(sec);
   ms = argc < 4 ? GetMillisecondsFrom(this) : ToNumber(ms);
   var time = MakeTime(hour, min, sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(Day(t), time))));
+  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -972,7 +934,7 @@
   sec = argc < 3 ? GetUTCSecondsFrom(this) : ToNumber(sec);
   ms = argc < 4 ? GetUTCMillisecondsFrom(this) : ToNumber(ms);
   var time = MakeTime(hour, min, sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(Day(t), time)));
+  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -980,7 +942,7 @@
 function DateSetDate(date) {
   var t = LocalTime(DATE_VALUE(this));
   date = ToNumber(date);
-  var day = MakeDay(YearFromTime(t), MonthFromTime(t), date);
+  var day = MakeDay(YEAR_FROM_TIME(t), MONTH_FROM_TIME(t), date);
   return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
@@ -989,7 +951,7 @@
 function DateSetUTCDate(date) {
   var t = DATE_VALUE(this);
   date = ToNumber(date);
-  var day = MakeDay(YearFromTime(t), MonthFromTime(t), date);
+  var day = MakeDay(YEAR_FROM_TIME(t), MONTH_FROM_TIME(t), date);
   return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
 
@@ -999,7 +961,7 @@
   var t = LocalTime(DATE_VALUE(this));
   month = ToNumber(month);
   date = %_ArgumentsLength() < 2 ? GetDateFrom(this) : ToNumber(date);
-  var day = MakeDay(YearFromTime(t), month, date);
+  var day = MakeDay(YEAR_FROM_TIME(t), month, date);
   return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
@@ -1009,7 +971,7 @@
   var t = DATE_VALUE(this);
   month = ToNumber(month);
   date = %_ArgumentsLength() < 2 ? GetUTCDateFrom(this) : ToNumber(date);
-  var day = MakeDay(YearFromTime(t), month, date);
+  var day = MakeDay(YEAR_FROM_TIME(t), month, date);
   return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
 
@@ -1020,8 +982,8 @@
   t = NUMBER_IS_NAN(t) ? 0 : LocalTimeNoCheck(t);
   year = ToNumber(year);
   var argc = %_ArgumentsLength();
-  month = argc < 2 ? MonthFromTime(t) : ToNumber(month);
-  date = argc < 3 ? DateFromTime(t) : ToNumber(date);
+  month = argc < 2 ? MONTH_FROM_TIME(t) : ToNumber(month);
+  date = argc < 3 ? DATE_FROM_TIME(t) : ToNumber(date);
   var day = MakeDay(year, month, date);
   return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
@@ -1033,8 +995,8 @@
   if (NUMBER_IS_NAN(t)) t = 0;
   var argc = %_ArgumentsLength();
   year = ToNumber(year);
-  month = argc < 2 ? MonthFromTime(t) : ToNumber(month);
-  date = argc < 3 ? DateFromTime(t) : ToNumber(date);
+  month = argc < 2 ? MONTH_FROM_TIME(t) : ToNumber(month);
+  date = argc < 3 ? DATE_FROM_TIME(t) : ToNumber(date);
   var day = MakeDay(year, month, date);
   return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
@@ -1046,9 +1008,9 @@
   if (NUMBER_IS_NAN(t)) return kInvalidDate;
   // Return UTC string of the form: Sat, 31 Jan 1970 23:00:00 GMT
   return WeekDays[WeekDay(t)] + ', '
-      + TwoDigitString(DateFromTime(t)) + ' '
-      + Months[MonthFromTime(t)] + ' '
-      + YearFromTime(t) + ' '
+      + TwoDigitString(DATE_FROM_TIME(t)) + ' '
+      + Months[MONTH_FROM_TIME(t)] + ' '
+      + YEAR_FROM_TIME(t) + ' '
       + TimeString(t) + ' GMT';
 }
 
@@ -1057,7 +1019,7 @@
 function DateGetYear() {
   var t = DATE_VALUE(this);
   if (NUMBER_IS_NAN(t)) return $NaN;
-  return YearFromTime(LocalTimeNoCheck(t)) - 1900;
+  return YEAR_FROM_TIME(LocalTimeNoCheck(t)) - 1900;
 }
 
 
@@ -1069,7 +1031,7 @@
   if (NUMBER_IS_NAN(year)) return %_SetValueOf(this, $NaN);
   year = (0 <= TO_INTEGER(year) && TO_INTEGER(year) <= 99)
       ? 1900 + TO_INTEGER(year) : year;
-  var day = MakeDay(year, MonthFromTime(t), DateFromTime(t));
+  var day = MakeDay(year, MONTH_FROM_TIME(t), DATE_FROM_TIME(t));
   return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
@@ -1086,16 +1048,19 @@
 }
 
 
-function PadInt(n) {
-  // Format integers to have at least two digits.
-  return n < 10 ? '0' + n : n;
+function PadInt(n, digits) {
+  if (digits == 1) return n;
+  return n < MathPow(10, digits - 1) ? '0' + PadInt(n, digits - 1) : n;
 }
 
 
 function DateToISOString() {
-  return this.getUTCFullYear() + '-' + PadInt(this.getUTCMonth() + 1) +
-      '-' + PadInt(this.getUTCDate()) + 'T' + PadInt(this.getUTCHours()) +
-      ':' + PadInt(this.getUTCMinutes()) + ':' + PadInt(this.getUTCSeconds()) +
+  var t = DATE_VALUE(this);
+  if (NUMBER_IS_NAN(t)) return kInvalidDate;
+  return this.getUTCFullYear() + '-' + PadInt(this.getUTCMonth() + 1, 2) +
+      '-' + PadInt(this.getUTCDate(), 2) + 'T' + PadInt(this.getUTCHours(), 2) +
+      ':' + PadInt(this.getUTCMinutes(), 2) + ':' + PadInt(this.getUTCSeconds(), 2) +
+      '.' + PadInt(this.getUTCMilliseconds(), 3) +
       'Z';
 }
 
diff --git a/src/debug.cc b/src/debug.cc
index 2c4552e..fbe0939 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -2483,7 +2483,24 @@
 }
 
 
-bool Debugger::StartAgent(const char* name, int port) {
+static void StubMessageHandler2(const v8::Debug::Message& message) {
+  // Simply ignore message.
+}
+
+
+bool Debugger::StartAgent(const char* name, int port,
+                          bool wait_for_connection) {
+  if (wait_for_connection) {
+    // Suspend V8 if it is already running or set V8 to suspend whenever
+    // it starts.
+    // Provide stub message handler; V8 auto-continues each suspend
+    // when there is no message handler; we doesn't need it.
+    // Once become suspended, V8 will stay so indefinitely long, until remote
+    // debugger connects and issues "continue" command.
+    Debugger::message_handler_ = StubMessageHandler2;
+    v8::Debug::DebugBreak();
+  }
+
   if (Socket::Setup()) {
     agent_ = new DebuggerAgent(name, port);
     agent_->Start();
diff --git a/src/debug.h b/src/debug.h
index 24f0db4..c37e08b 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -636,7 +636,8 @@
                              bool* pending_exception);
 
   // Start the debugger agent listening on the provided port.
-  static bool StartAgent(const char* name, int port);
+  static bool StartAgent(const char* name, int port,
+                         bool wait_for_connection = false);
 
   // Stop the debugger agent.
   static void StopAgent();
diff --git a/src/fast-codegen.cc b/src/fast-codegen.cc
index b15a673..455dd5f 100644
--- a/src/fast-codegen.cc
+++ b/src/fast-codegen.cc
@@ -67,13 +67,47 @@
     case Slot::LOCAL:
       offset += JavaScriptFrameConstants::kLocal0Offset;
       break;
-    default:
+    case Slot::CONTEXT:
+    case Slot::LOOKUP:
       UNREACHABLE();
   }
   return offset;
 }
 
 
+void FastCodeGenerator::Apply(Expression::Context context, Register reg) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      break;
+    case Expression::kValue:
+      __ push(reg);
+      break;
+    case Expression::kTest:
+      TestAndBranch(reg, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      __ push(reg);
+      TestAndBranch(reg, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
+      break;
+    }
+    case Expression::kTestValue: {
+      Label discard;
+      __ push(reg);
+      TestAndBranch(reg, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(true_label_);
+    }
+  }
+}
+
+
 void FastCodeGenerator::VisitDeclarations(
     ZoneList<Declaration*>* declarations) {
   int length = declarations->length();
@@ -162,7 +196,7 @@
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
-    case Expression::kEffect:  // Fall through.
+    case Expression::kEffect:
     case Expression::kTest:
       // The value of the left subexpression is not needed.
       expected = Expression::kTest;
@@ -192,36 +226,33 @@
 #endif
 
   Label eval_right, done;
-  Label* saved_true = true_label_;
-  Label* saved_false = false_label_;
 
-  // Set up the appropriate context for the left subexpression based on the
-  // operation and our own context.
+  // Set up the appropriate context for the left subexpression based
+  // on the operation and our own context.  Initially assume we can
+  // inherit both true and false labels from our context.
+  Label* if_true = true_label_;
+  Label* if_false = false_label_;
   if (expr->op() == Token::OR) {
-    // If there is no usable true label in the OR expression's context, use
-    // the end of this expression, otherwise inherit the same true label.
+    // If we are not in some kind of a test context, we did not inherit a
+    // true label from our context.  Use the end of the expression.
     if (expr->context() == Expression::kEffect ||
         expr->context() == Expression::kValue) {
-      true_label_ = &done;
+      if_true = &done;
     }
-    // The false label is the label of the second subexpression.
-    false_label_ = &eval_right;
+    // The false label is the label of the right subexpression.
+    if_false = &eval_right;
   } else {
     ASSERT_EQ(Token::AND, expr->op());
-    // The true label is the label of the second subexpression.
-    true_label_ = &eval_right;
-    // If there is no usable false label in the AND expression's context,
-    // use the end of the expression, otherwise inherit the same false
-    // label.
+    // The true label is the label of the right subexpression.
+    if_true = &eval_right;
+    // If we are not in some kind of a test context, we did not inherit a
+    // false label from our context.  Use the end of the expression.
     if (expr->context() == Expression::kEffect ||
         expr->context() == Expression::kValue) {
-      false_label_ = &done;
+      if_false = &done;
     }
   }
-
-  Visit(expr->left());
-  true_label_ = saved_true;
-  false_label_ = saved_false;
+  VisitForControl(expr->left(), if_true, if_false);
 
   __ bind(&eval_right);
   Visit(expr->right());
@@ -254,19 +285,11 @@
 
 void FastCodeGenerator::VisitIfStatement(IfStatement* stmt) {
   Comment cmnt(masm_, "[ IfStatement");
-  // Expressions cannot recursively enter statements, there are no labels in
-  // the state.
-  ASSERT_EQ(NULL, true_label_);
-  ASSERT_EQ(NULL, false_label_);
+  SetStatementPosition(stmt);
   Label then_part, else_part, done;
 
   // Do not worry about optimizing for empty then or else bodies.
-  true_label_ = &then_part;
-  false_label_ = &else_part;
-  ASSERT(stmt->condition()->context() == Expression::kTest);
-  Visit(stmt->condition());
-  true_label_ = NULL;
-  false_label_ = NULL;
+  VisitForControl(stmt->condition(), &then_part, &else_part);
 
   __ bind(&then_part);
   Visit(stmt->then_statement());
@@ -281,6 +304,7 @@
 
 void FastCodeGenerator::VisitContinueStatement(ContinueStatement* stmt) {
   Comment cmnt(masm_,  "[ ContinueStatement");
+  SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
   while (!current->IsContinueTarget(stmt->target())) {
@@ -296,6 +320,7 @@
 
 void FastCodeGenerator::VisitBreakStatement(BreakStatement* stmt) {
   Comment cmnt(masm_,  "[ BreakStatement");
+  SetStatementPosition(stmt);
   NestedStatement* current = nesting_stack_;
   int stack_depth = 0;
   while (!current->IsBreakTarget(stmt->target())) {
@@ -311,6 +336,7 @@
 
 void FastCodeGenerator::VisitReturnStatement(ReturnStatement* stmt) {
   Comment cmnt(masm_, "[ ReturnStatement");
+  SetStatementPosition(stmt);
   Expression* expr = stmt->expression();
   // Complete the statement based on the type of the subexpression.
   if (expr->AsLiteral() != NULL) {
@@ -372,6 +398,7 @@
 
 void FastCodeGenerator::VisitDoWhileStatement(DoWhileStatement* stmt) {
   Comment cmnt(masm_, "[ DoWhileStatement");
+  SetStatementPosition(stmt);
   Label body, stack_limit_hit, stack_check_success;
 
   Iteration loop_statement(this, stmt);
@@ -384,17 +411,8 @@
   __ StackLimitCheck(&stack_limit_hit);
   __ bind(&stack_check_success);
 
-  // We are not in an expression context because we have been compiling
-  // statements.  Set up a test expression context for the condition.
   __ bind(loop_statement.continue_target());
-  ASSERT_EQ(NULL, true_label_);
-  ASSERT_EQ(NULL, false_label_);
-  true_label_ = &body;
-  false_label_ = loop_statement.break_target();
-  ASSERT(stmt->cond()->context() == Expression::kTest);
-  Visit(stmt->cond());
-  true_label_ = NULL;
-  false_label_ = NULL;
+  VisitForControl(stmt->cond(), &body, loop_statement.break_target());
 
   __ bind(&stack_limit_hit);
   StackCheckStub stack_stub;
@@ -409,6 +427,7 @@
 
 void FastCodeGenerator::VisitWhileStatement(WhileStatement* stmt) {
   Comment cmnt(masm_, "[ WhileStatement");
+  SetStatementPosition(stmt);
   Label body, stack_limit_hit, stack_check_success;
 
   Iteration loop_statement(this, stmt);
@@ -425,16 +444,7 @@
   __ StackLimitCheck(&stack_limit_hit);
   __ bind(&stack_check_success);
 
-  // We are not in an expression context because we have been compiling
-  // statements.  Set up a test expression context for the condition.
-  ASSERT_EQ(NULL, true_label_);
-  ASSERT_EQ(NULL, false_label_);
-  true_label_ = &body;
-  false_label_ = loop_statement.break_target();
-  ASSERT(stmt->cond()->context() == Expression::kTest);
-  Visit(stmt->cond());
-  true_label_ = NULL;
-  false_label_ = NULL;
+  VisitForControl(stmt->cond(), &body, loop_statement.break_target());
 
   __ bind(&stack_limit_hit);
   StackCheckStub stack_stub;
@@ -457,11 +467,52 @@
 
 
 void FastCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
-  UNREACHABLE();
+  Comment cmnt(masm_, "[ TryCatchStatement");
+  SetStatementPosition(stmt);
+  // The try block adds a handler to the exception handler chain
+  // before entering, and removes it again when exiting normally.
+  // If an exception is thrown during execution of the try block,
+  // control is passed to the handler, which also consumes the handler.
+  // At this point, the exception is in a register, and store it in
+  // the temporary local variable (prints as ".catch-var") before
+  // executing the catch block. The catch block has been rewritten
+  // to introduce a new scope to bind the catch variable and to remove
+  // that scope again afterwards.
+
+  Label try_handler_setup, catch_entry, done;
+
+  __ Call(&try_handler_setup);
+  // Try handler code, exception in result register.
+
+  // Store exception in local .catch variable before executing catch block.
+  {
+    // The catch variable is *always* a variable proxy for a local variable.
+    Variable* catch_var = stmt->catch_var()->AsVariableProxy()->AsVariable();
+    ASSERT_NOT_NULL(catch_var);
+    Slot* variable_slot = catch_var->slot();
+    ASSERT_NOT_NULL(variable_slot);
+    ASSERT_EQ(Slot::LOCAL, variable_slot->type());
+    StoreToFrameField(SlotOffset(variable_slot), result_register());
+  }
+
+  Visit(stmt->catch_block());
+  __ jmp(&done);
+
+  // Try block code. Sets up the exception handler chain.
+  __ bind(&try_handler_setup);
+  {
+    TryCatch try_block(this, &catch_entry);
+    __ PushTryHandler(IN_JAVASCRIPT, TRY_CATCH_HANDLER);
+    Visit(stmt->try_block());
+    __ PopTryHandler();
+  }
+  __ bind(&done);
 }
 
 
 void FastCodeGenerator::VisitTryFinallyStatement(TryFinallyStatement* stmt) {
+  Comment cmnt(masm_, "[ TryFinallyStatement");
+  SetStatementPosition(stmt);
   // Try finally is compiled by setting up a try-handler on the stack while
   // executing the try body, and removing it again afterwards.
   //
@@ -474,7 +525,7 @@
   //    its outward control transfer.
   // 3. by exiting the try-block with a thrown exception.
   //    This can happen in nested function calls. It traverses the try-handler
-  //    chaing and consumes the try-handler entry before jumping to the
+  //    chain and consumes the try-handler entry before jumping to the
   //    handler code. The handler code then calls the finally-block before
   //    rethrowing the exception.
   //
@@ -497,14 +548,15 @@
     // is retained by the finally block.
     // Call the finally block and then rethrow the exception.
     __ Call(&finally_entry);
-    ThrowException();
+    __ push(result_register());
+    __ CallRuntime(Runtime::kReThrow, 1);
   }
 
   __ bind(&finally_entry);
   {
     // Finally block implementation.
-    EnterFinallyBlock();
     Finally finally_block(this);
+    EnterFinallyBlock();
     Visit(stmt->finally_block());
     ExitFinallyBlock();  // Return to the calling code.
   }
@@ -512,9 +564,9 @@
   __ bind(&try_handler_setup);
   {
     // Setup try handler (stack pointer registers).
-    __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
     TryFinally try_block(this, &finally_entry);
-    VisitStatements(stmt->try_block()->statements());
+    __ PushTryHandler(IN_JAVASCRIPT, TRY_FINALLY_HANDLER);
+    Visit(stmt->try_block());
     __ PopTryHandler();
   }
   // Execute the finally block on the way out.
@@ -546,14 +598,7 @@
 
 
   Label true_case, false_case, done;
-  Label* saved_true = true_label_;
-  Label* saved_false = false_label_;
-
-  true_label_ = &true_case;
-  false_label_ = &false_case;
-  Visit(expr->condition());
-  true_label_ = saved_true;
-  false_label_ = saved_false;
+  VisitForControl(expr->condition(), &true_case, &false_case);
 
   __ bind(&true_case);
   Visit(expr->then_expression());
@@ -581,7 +626,7 @@
 
 void FastCodeGenerator::VisitLiteral(Literal* expr) {
   Comment cmnt(masm_, "[ Literal");
-  Move(expr->context(), expr);
+  Apply(expr->context(), expr);
 }
 
 
@@ -634,7 +679,7 @@
         EmitNamedPropertyLoad(prop, Expression::kValue);
         break;
       case KEYED_PROPERTY:
-        EmitKeyedPropertyLoad(Expression::kValue);
+        EmitKeyedPropertyLoad(prop, Expression::kValue);
         break;
     }
   }
@@ -652,7 +697,8 @@
   // Store the value.
   switch (assign_type) {
     case VARIABLE:
-      EmitVariableAssignment(expr);
+      EmitVariableAssignment(expr->target()->AsVariableProxy()->var(),
+                             expr->context());
       break;
     case NAMED_PROPERTY:
       EmitNamedPropertyAssignment(expr);
@@ -665,12 +711,29 @@
 
 
 void FastCodeGenerator::VisitCatchExtensionObject(CatchExtensionObject* expr) {
-  UNREACHABLE();
+  // Call runtime routine to allocate the catch extension object and
+  // assign the exception value to the catch variable.
+  Comment cmnt(masm_, "[ CatchExtensionObject");
+
+  // Push key string.
+  ASSERT_EQ(Expression::kValue, expr->key()->context());
+  Visit(expr->key());
+  ASSERT_EQ(Expression::kValue, expr->value()->context());
+  Visit(expr->value());
+
+  // Create catch extension object.
+  __ CallRuntime(Runtime::kCreateCatchExtensionObject, 2);
+
+  __ push(result_register());
 }
 
 
 void FastCodeGenerator::VisitThrow(Throw* expr) {
-  UNREACHABLE();
+  Comment cmnt(masm_, "[ Throw");
+  Visit(expr->exception());
+  // Exception is on stack.
+  __ CallRuntime(Runtime::kThrow, 1);
+  // Never returns here.
 }
 
 
diff --git a/src/fast-codegen.h b/src/fast-codegen.h
index 54f0df1..ecac8e7 100644
--- a/src/fast-codegen.h
+++ b/src/fast-codegen.h
@@ -212,26 +212,48 @@
 
 
   int SlotOffset(Slot* slot);
-  void Move(Expression::Context destination, Register source);
-  void Move(Expression::Context destination, Slot* source, Register scratch);
-  void Move(Expression::Context destination, Literal* source);
+
+  // Emit code to complete the evaluation of an expression based on its
+  // expression context and given its value is in a register, non-lookup
+  // slot, or a literal.
+  void Apply(Expression::Context context, Register reg);
+  void Apply(Expression::Context context, Slot* slot, Register scratch);
+  void Apply(Expression::Context context, Literal* lit);
+
+  // Emit code to complete the evaluation of an expression based on its
+  // expression context and given its value is on top of the stack.
+  void ApplyTOS(Expression::Context context);
+
+  // Emit code to discard count elements from the top of stack, then
+  // complete the evaluation of an expression based on its expression
+  // context and given its value is in a register.
+  void DropAndApply(int count, Expression::Context context, Register reg);
+
   void Move(Slot* dst, Register source, Register scratch1, Register scratch2);
   void Move(Register dst, Slot* source);
 
-  // Templated to allow for Operand on intel and MemOperand on ARM.
-  template <typename MemoryLocation>
-  MemoryLocation CreateSlotOperand(Slot* slot, Register scratch);
-
-  // Drop the TOS, and store source to destination.
-  // If destination is TOS, just overwrite TOS with source.
-  void DropAndMove(Expression::Context destination,
-                   Register source,
-                   int drop_count = 1);
+  // Return an operand used to read/write to a known (ie, non-LOOKUP) slot.
+  // May emit code to traverse the context chain, destroying the scratch
+  // register.
+  MemOperand EmitSlotSearch(Slot* slot, Register scratch);
 
   // Test the JavaScript value in source as if in a test context, compile
   // control flow to a pair of labels.
   void TestAndBranch(Register source, Label* true_label, Label* false_label);
 
+  void VisitForControl(Expression* expr, Label* if_true, Label* if_false) {
+    ASSERT(expr->context() == Expression::kTest ||
+           expr->context() == Expression::kValueTest ||
+           expr->context() == Expression::kTestValue);
+    Label* saved_true = true_label_;
+    Label* saved_false = false_label_;
+    true_label_ = if_true;
+    false_label_ = if_false;
+    Visit(expr);
+    true_label_ = saved_true;
+    false_label_ = saved_false;
+  }
+
   void VisitDeclarations(ZoneList<Declaration*>* declarations);
   void DeclareGlobals(Handle<FixedArray> pairs);
 
@@ -247,13 +269,13 @@
 
   // Platform-specific support for compiling assignments.
 
-  // Load a value from a named property and push the result on the stack.
+  // Load a value from a named property.
   // The receiver is left on the stack by the IC.
   void EmitNamedPropertyLoad(Property* expr, Expression::Context context);
 
-  // Load a value from a named property and push the result on the stack.
+  // Load a value from a keyed property.
   // The receiver and the key is left on the stack by the IC.
-  void EmitKeyedPropertyLoad(Expression::Context context);
+  void EmitKeyedPropertyLoad(Property* expr, Expression::Context context);
 
   // Apply the compound assignment operator. Expects both operands on top
   // of the stack.
@@ -261,7 +283,7 @@
 
   // Complete a variable assignment.  The right-hand-side value is expected
   // on top of the stack.
-  void EmitVariableAssignment(Assignment* expr);
+  void EmitVariableAssignment(Variable* var, Expression::Context context);
 
   // Complete a named property assignment.  The receiver and right-hand-side
   // value are expected on top of the stack.
@@ -279,7 +301,6 @@
   // Non-local control flow support.
   void EnterFinallyBlock();
   void ExitFinallyBlock();
-  void ThrowException();
 
   // Loop nesting counter.
   int loop_depth() { return loop_depth_; }
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index 88fda12..f912fc5 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -198,6 +198,9 @@
 DEFINE_bool(canonicalize_object_literal_maps, true,
             "Canonicalize maps for object literals.")
 
+DEFINE_bool(use_big_map_space, true,
+            "Use big map space, but don't compact if it grew too big.")
+
 // mksnapshot.cc
 DEFINE_bool(h, false, "print this message")
 DEFINE_bool(new_snapshot, true, "use new snapshot implementation")
@@ -228,6 +231,7 @@
 // Regexp
 DEFINE_bool(trace_regexps, false, "trace regexp execution")
 DEFINE_bool(regexp_optimization, true, "generate optimized regexp code")
+DEFINE_bool(regexp_entry_native, true, "use native code to enter regexp")
 
 // Testing flags test/cctest/test-{flags,api,serialization}.cc
 DEFINE_bool(testing_bool_flag, true, "testing_bool_flag")
@@ -325,6 +329,9 @@
             "(requires heap_stats)")
 
 // Regexp
+DEFINE_bool(regexp_possessive_quantifier,
+            false,
+            "enable possessive quantifier syntax for testing")
 DEFINE_bool(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
 DEFINE_bool(trace_regexp_assembler,
             false,
diff --git a/src/frames.cc b/src/frames.cc
index 7c327dd..2f90a31 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -306,7 +306,7 @@
 
 
 void StackHandler::Uncook(Code* code) {
-  ASSERT(MarkCompactCollector::IsCompacting());
+  ASSERT(MarkCompactCollector::HasCompacted());
   set_pc(code->instruction_start() + OffsetFrom(pc()));
   ASSERT(code->contains(pc()));
 }
@@ -336,7 +336,7 @@
 void StackFrame::UncookFramesForThread(ThreadLocalTop* thread) {
   // Only uncooking frames when the collector is compacting and thus moving code
   // around.
-  ASSERT(MarkCompactCollector::IsCompacting());
+  ASSERT(MarkCompactCollector::HasCompacted());
   ASSERT(thread->stack_is_cooked());
   for (StackFrameIterator it(thread); !it.done(); it.Advance()) {
     it.frame()->Uncook();
diff --git a/src/heap-inl.h b/src/heap-inl.h
index 00fad54..bd4f86b 100644
--- a/src/heap-inl.h
+++ b/src/heap-inl.h
@@ -54,7 +54,8 @@
   ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
   ASSERT(space != NEW_SPACE ||
          retry_space == OLD_POINTER_SPACE ||
-         retry_space == OLD_DATA_SPACE);
+         retry_space == OLD_DATA_SPACE ||
+         retry_space == LO_SPACE);
 #ifdef DEBUG
   if (FLAG_gc_interval >= 0 &&
       !disallow_allocation_failure_ &&
@@ -196,12 +197,23 @@
   // other object types are promoted to old pointer space.  We do not use
   // object->IsHeapNumber() and object->IsSeqString() because we already
   // know that object has the heap object tag.
-  ASSERT((type != CODE_TYPE) && (type != MAP_TYPE));
-  bool has_pointers =
-      type != HEAP_NUMBER_TYPE &&
-      (type >= FIRST_NONSTRING_TYPE ||
-       (type & kStringRepresentationMask) != kSeqStringTag);
-  return has_pointers ? OLD_POINTER_SPACE : OLD_DATA_SPACE;
+
+  // These objects are never allocated in new space.
+  ASSERT(type != MAP_TYPE);
+  ASSERT(type != CODE_TYPE);
+  ASSERT(type != ODDBALL_TYPE);
+  ASSERT(type != JS_GLOBAL_PROPERTY_CELL_TYPE);
+
+  if (type < FIRST_NONSTRING_TYPE) {
+    // There are three string representations: sequential strings, cons
+    // strings, and external strings.  Only cons strings contain
+    // non-map-word pointers to heap objects.
+    return ((type & kStringRepresentationMask) == kConsStringTag)
+        ? OLD_POINTER_SPACE
+        : OLD_DATA_SPACE;
+  } else {
+    return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
+  }
 }
 
 
diff --git a/src/heap.cc b/src/heap.cc
index 7a66038..fba2e87 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -479,6 +479,65 @@
 }
 
 
+void Heap::ReserveSpace(
+    int new_space_size,
+    int pointer_space_size,
+    int data_space_size,
+    int code_space_size,
+    int map_space_size,
+    int cell_space_size,
+    int large_object_size) {
+  NewSpace* new_space = Heap::new_space();
+  PagedSpace* old_pointer_space = Heap::old_pointer_space();
+  PagedSpace* old_data_space = Heap::old_data_space();
+  PagedSpace* code_space = Heap::code_space();
+  PagedSpace* map_space = Heap::map_space();
+  PagedSpace* cell_space = Heap::cell_space();
+  LargeObjectSpace* lo_space = Heap::lo_space();
+  bool gc_performed = true;
+  while (gc_performed) {
+    gc_performed = false;
+    if (!new_space->ReserveSpace(new_space_size)) {
+      Heap::CollectGarbage(new_space_size, NEW_SPACE);
+      gc_performed = true;
+    }
+    if (!old_pointer_space->ReserveSpace(pointer_space_size)) {
+      Heap::CollectGarbage(pointer_space_size, OLD_POINTER_SPACE);
+      gc_performed = true;
+    }
+    if (!(old_data_space->ReserveSpace(data_space_size))) {
+      Heap::CollectGarbage(data_space_size, OLD_DATA_SPACE);
+      gc_performed = true;
+    }
+    if (!(code_space->ReserveSpace(code_space_size))) {
+      Heap::CollectGarbage(code_space_size, CODE_SPACE);
+      gc_performed = true;
+    }
+    if (!(map_space->ReserveSpace(map_space_size))) {
+      Heap::CollectGarbage(map_space_size, MAP_SPACE);
+      gc_performed = true;
+    }
+    if (!(cell_space->ReserveSpace(cell_space_size))) {
+      Heap::CollectGarbage(cell_space_size, CELL_SPACE);
+      gc_performed = true;
+    }
+    // We add a slack-factor of 2 in order to have space for the remembered
+    // set and a series of large-object allocations that are only just larger
+    // than the page size.
+    large_object_size *= 2;
+    // The ReserveSpace method on the large object space checks how much
+    // we can expand the old generation.  This includes expansion caused by
+    // allocation in the other spaces.
+    large_object_size += cell_space_size + map_space_size + code_space_size +
+        data_space_size + pointer_space_size;
+    if (!(lo_space->ReserveSpace(large_object_size))) {
+      Heap::CollectGarbage(large_object_size, LO_SPACE);
+      gc_performed = true;
+    }
+  }
+}
+
+
 void Heap::EnsureFromSpaceIsCommitted() {
   if (new_space_.CommitFromSpaceIfNeeded()) return;
 
@@ -576,6 +635,8 @@
 
   Top::MarkCompactPrologue(is_compacting);
   ThreadManager::MarkCompactPrologue(is_compacting);
+
+  if (is_compacting) FlushNumberStringCache();
 }
 
 
@@ -804,7 +865,8 @@
     }
   }
 
-  ExternalStringTable::ShrinkNewStrings(last - start);
+  ASSERT(last <= end);
+  ExternalStringTable::ShrinkNewStrings(static_cast<int>(last - start));
 }
 
 
@@ -1354,9 +1416,6 @@
   STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
 
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = OLD_DATA_SPACE;
-
   Object* result = AllocateRaw(HeapNumber::kSize, space, OLD_DATA_SPACE);
   if (result->IsFailure()) return result;
 
@@ -1576,10 +1635,7 @@
 
   CreateFixedStubs();
 
-  // Allocate the number->string conversion cache
-  obj = AllocateFixedArray(kNumberStringCacheSize * 2);
-  if (obj->IsFailure()) return false;
-  set_number_string_cache(FixedArray::cast(obj));
+  if (InitializeNumberStringCache()->IsFailure()) return false;
 
   // Allocate cache for single character strings.
   obj = AllocateFixedArray(String::kMaxAsciiCharCode+1);
@@ -1610,25 +1666,45 @@
 }
 
 
+Object* Heap::InitializeNumberStringCache() {
+  // Compute the size of the number string cache based on the max heap size.
+  // max_semispace_size_ == 512 KB => number_string_cache_size = 32.
+  // max_semispace_size_ ==   8 MB => number_string_cache_size = 16KB.
+  int number_string_cache_size = max_semispace_size_ / 512;
+  number_string_cache_size = Max(32, Min(16*KB, number_string_cache_size));
+  Object* obj = AllocateFixedArray(number_string_cache_size * 2);
+  if (!obj->IsFailure()) set_number_string_cache(FixedArray::cast(obj));
+  return obj;
+}
+
+
+void Heap::FlushNumberStringCache() {
+  // Flush the number to string cache.
+  int len = number_string_cache()->length();
+  for (int i = 0; i < len; i++) {
+    number_string_cache()->set_undefined(i);
+  }
+}
+
+
 static inline int double_get_hash(double d) {
   DoubleRepresentation rep(d);
-  return ((static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) &
-          (Heap::kNumberStringCacheSize - 1));
+  return static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32);
 }
 
 
 static inline int smi_get_hash(Smi* smi) {
-  return (smi->value() & (Heap::kNumberStringCacheSize - 1));
+  return smi->value();
 }
 
 
-
 Object* Heap::GetNumberStringCache(Object* number) {
   int hash;
+  int mask = (number_string_cache()->length() >> 1) - 1;
   if (number->IsSmi()) {
-    hash = smi_get_hash(Smi::cast(number));
+    hash = smi_get_hash(Smi::cast(number)) & mask;
   } else {
-    hash = double_get_hash(number->Number());
+    hash = double_get_hash(number->Number()) & mask;
   }
   Object* key = number_string_cache()->get(hash * 2);
   if (key == number) {
@@ -1644,11 +1720,12 @@
 
 void Heap::SetNumberStringCache(Object* number, String* string) {
   int hash;
+  int mask = (number_string_cache()->length() >> 1) - 1;
   if (number->IsSmi()) {
-    hash = smi_get_hash(Smi::cast(number));
+    hash = smi_get_hash(Smi::cast(number)) & mask;
     number_string_cache()->set(hash * 2, number, SKIP_WRITE_BARRIER);
   } else {
-    hash = double_get_hash(number->Number());
+    hash = double_get_hash(number->Number()) & mask;
     number_string_cache()->set(hash * 2, number);
   }
   number_string_cache()->set(hash * 2 + 1, string);
@@ -1762,7 +1839,6 @@
   // Statically ensure that it is safe to allocate proxies in paged spaces.
   STATIC_ASSERT(Proxy::kSize <= Page::kMaxHeapObjectSize);
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-  if (always_allocate()) space = OLD_DATA_SPACE;
   Object* result = Allocate(proxy_map(), space);
   if (result->IsFailure()) return result;
 
@@ -1902,8 +1978,7 @@
 
   Map* map = is_ascii ? cons_ascii_string_map() : cons_string_map();
 
-  Object* result = Allocate(map,
-                            always_allocate() ? OLD_POINTER_SPACE : NEW_SPACE);
+  Object* result = Allocate(map, NEW_SPACE);
   if (result->IsFailure()) return result;
   ConsString* cons_string = ConsString::cast(result);
   WriteBarrierMode mode = cons_string->GetWriteBarrierMode();
@@ -1967,8 +2042,7 @@
   }
 
   Map* map = external_ascii_string_map();
-  Object* result = Allocate(map,
-                            always_allocate() ? OLD_DATA_SPACE : NEW_SPACE);
+  Object* result = Allocate(map, NEW_SPACE);
   if (result->IsFailure()) return result;
 
   ExternalAsciiString* external_string = ExternalAsciiString::cast(result);
@@ -1989,8 +2063,7 @@
   }
 
   Map* map = Heap::external_string_map();
-  Object* result = Allocate(map,
-                            always_allocate() ? OLD_DATA_SPACE : NEW_SPACE);
+  Object* result = Allocate(map, NEW_SPACE);
   if (result->IsFailure()) return result;
 
   ExternalTwoByteString* external_string = ExternalTwoByteString::cast(result);
@@ -2025,15 +2098,16 @@
 
 
 Object* Heap::AllocateByteArray(int length, PretenureFlag pretenure) {
+  if (length < 0 || length > ByteArray::kMaxLength) {
+    return Failure::OutOfMemoryException();
+  }
   if (pretenure == NOT_TENURED) {
     return AllocateByteArray(length);
   }
   int size = ByteArray::SizeFor(length);
-  AllocationSpace space =
-      size > MaxObjectSizeInPagedSpace() ? LO_SPACE : OLD_DATA_SPACE;
-
-  Object* result = AllocateRaw(size, space, OLD_DATA_SPACE);
-
+  Object* result = (size <= MaxObjectSizeInPagedSpace())
+      ? old_data_space_->AllocateRaw(size)
+      : lo_space_->AllocateRaw(size);
   if (result->IsFailure()) return result;
 
   reinterpret_cast<Array*>(result)->set_map(byte_array_map());
@@ -2043,15 +2117,13 @@
 
 
 Object* Heap::AllocateByteArray(int length) {
+  if (length < 0 || length > ByteArray::kMaxLength) {
+    return Failure::OutOfMemoryException();
+  }
   int size = ByteArray::SizeFor(length);
   AllocationSpace space =
-      size > MaxObjectSizeInPagedSpace() ? LO_SPACE : NEW_SPACE;
-
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = LO_SPACE;
-
+      (size > MaxObjectSizeInPagedSpace()) ? LO_SPACE : NEW_SPACE;
   Object* result = AllocateRaw(size, space, OLD_DATA_SPACE);
-
   if (result->IsFailure()) return result;
 
   reinterpret_cast<Array*>(result)->set_map(byte_array_map());
@@ -2076,12 +2148,7 @@
                                  uint8_t* external_pointer,
                                  PretenureFlag pretenure) {
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = OLD_DATA_SPACE;
-
   Object* result = AllocateRaw(PixelArray::kAlignedSize, space, OLD_DATA_SPACE);
-
   if (result->IsFailure()) return result;
 
   reinterpret_cast<PixelArray*>(result)->set_map(pixel_array_map());
@@ -2097,14 +2164,9 @@
                                     void* external_pointer,
                                     PretenureFlag pretenure) {
   AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = OLD_DATA_SPACE;
-
   Object* result = AllocateRaw(ExternalArray::kAlignedSize,
                                space,
                                OLD_DATA_SPACE);
-
   if (result->IsFailure()) return result;
 
   reinterpret_cast<ExternalArray*>(result)->set_map(
@@ -2193,9 +2255,12 @@
 Object* Heap::Allocate(Map* map, AllocationSpace space) {
   ASSERT(gc_state_ == NOT_IN_GC);
   ASSERT(map->instance_type() != MAP_TYPE);
-  Object* result = AllocateRaw(map->instance_size(),
-                               space,
-                               TargetSpaceId(map->instance_type()));
+  // If allocation failures are disallowed, we may allocate in a different
+  // space when new space is full and the object is not a large object.
+  AllocationSpace retry_space =
+      (space != NEW_SPACE) ? space : TargetSpaceId(map->instance_type());
+  Object* result =
+      AllocateRaw(map->instance_size(), space, retry_space);
   if (result->IsFailure()) return result;
   HeapObject::cast(result)->set_map(map);
 #ifdef ENABLE_LOGGING_AND_PROFILING
@@ -2383,7 +2448,6 @@
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   if (map->instance_size() > MaxObjectSizeInPagedSpace()) space = LO_SPACE;
-  if (always_allocate()) space = OLD_POINTER_SPACE;
   Object* obj = Allocate(map, space);
   if (obj->IsFailure()) return obj;
 
@@ -2658,12 +2722,16 @@
 Object* Heap::AllocateInternalSymbol(unibrow::CharacterStream* buffer,
                                      int chars,
                                      uint32_t hash_field) {
+  ASSERT(chars >= 0);
   // Ensure the chars matches the number of characters in the buffer.
   ASSERT(static_cast<unsigned>(chars) == buffer->Length());
   // Determine whether the string is ascii.
   bool is_ascii = true;
-  while (buffer->has_more() && is_ascii) {
-    if (buffer->GetNext() > unibrow::Utf8::kMaxOneByteChar) is_ascii = false;
+  while (buffer->has_more()) {
+    if (buffer->GetNext() > unibrow::Utf8::kMaxOneByteChar) {
+      is_ascii = false;
+      break;
+    }
   }
   buffer->Rewind();
 
@@ -2672,17 +2740,23 @@
   Map* map;
 
   if (is_ascii) {
+    if (chars > SeqAsciiString::kMaxLength) {
+      return Failure::OutOfMemoryException();
+    }
     map = ascii_symbol_map();
     size = SeqAsciiString::SizeFor(chars);
   } else {
+    if (chars > SeqTwoByteString::kMaxLength) {
+      return Failure::OutOfMemoryException();
+    }
     map = symbol_map();
     size = SeqTwoByteString::SizeFor(chars);
   }
 
   // Allocate string.
-  AllocationSpace space =
-      (size > MaxObjectSizeInPagedSpace()) ? LO_SPACE : OLD_DATA_SPACE;
-  Object* result = AllocateRaw(size, space, OLD_DATA_SPACE);
+  Object* result = (size > MaxObjectSizeInPagedSpace())
+      ? lo_space_->AllocateRaw(size)
+      : old_data_space_->AllocateRaw(size);
   if (result->IsFailure()) return result;
 
   reinterpret_cast<HeapObject*>(result)->set_map(map);
@@ -2702,22 +2776,28 @@
 
 
 Object* Heap::AllocateRawAsciiString(int length, PretenureFlag pretenure) {
-  AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = OLD_DATA_SPACE;
+  if (length < 0 || length > SeqAsciiString::kMaxLength) {
+    return Failure::OutOfMemoryException();
+  }
 
   int size = SeqAsciiString::SizeFor(length);
+  ASSERT(size <= SeqAsciiString::kMaxSize);
 
-  Object* result = Failure::OutOfMemoryException();
+  AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
+  AllocationSpace retry_space = OLD_DATA_SPACE;
+
   if (space == NEW_SPACE) {
-    result = size <= kMaxObjectSizeInNewSpace
-        ? new_space_.AllocateRaw(size)
-        : lo_space_->AllocateRaw(size);
-  } else {
-    if (size > MaxObjectSizeInPagedSpace()) space = LO_SPACE;
-    result = AllocateRaw(size, space, OLD_DATA_SPACE);
+    if (size > kMaxObjectSizeInNewSpace) {
+      // Allocate in large object space, retry space will be ignored.
+      space = LO_SPACE;
+    } else if (size > MaxObjectSizeInPagedSpace()) {
+      // Allocate in new space, retry in large object space.
+      retry_space = LO_SPACE;
+    }
+  } else if (space == OLD_DATA_SPACE && size > MaxObjectSizeInPagedSpace()) {
+    space = LO_SPACE;
   }
+  Object* result = AllocateRaw(size, space, retry_space);
   if (result->IsFailure()) return result;
 
   // Partially initialize the object.
@@ -2730,22 +2810,26 @@
 
 
 Object* Heap::AllocateRawTwoByteString(int length, PretenureFlag pretenure) {
-  AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
-
-  // New space can't cope with forced allocation.
-  if (always_allocate()) space = OLD_DATA_SPACE;
-
-  int size = SeqTwoByteString::SizeFor(length);
-
-  Object* result = Failure::OutOfMemoryException();
-  if (space == NEW_SPACE) {
-    result = size <= kMaxObjectSizeInNewSpace
-        ? new_space_.AllocateRaw(size)
-        : lo_space_->AllocateRaw(size);
-  } else {
-    if (size > MaxObjectSizeInPagedSpace()) space = LO_SPACE;
-    result = AllocateRaw(size, space, OLD_DATA_SPACE);
+  if (length < 0 || length > SeqTwoByteString::kMaxLength) {
+    return Failure::OutOfMemoryException();
   }
+  int size = SeqTwoByteString::SizeFor(length);
+  ASSERT(size <= SeqTwoByteString::kMaxSize);
+  AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
+  AllocationSpace retry_space = OLD_DATA_SPACE;
+
+  if (space == NEW_SPACE) {
+    if (size > kMaxObjectSizeInNewSpace) {
+      // Allocate in large object space, retry space will be ignored.
+      space = LO_SPACE;
+    } else if (size > MaxObjectSizeInPagedSpace()) {
+      // Allocate in new space, retry in large object space.
+      retry_space = LO_SPACE;
+    }
+  } else if (space == OLD_DATA_SPACE && size > MaxObjectSizeInPagedSpace()) {
+    space = LO_SPACE;
+  }
+  Object* result = AllocateRaw(size, space, retry_space);
   if (result->IsFailure()) return result;
 
   // Partially initialize the object.
@@ -2769,6 +2853,9 @@
 
 
 Object* Heap::AllocateRawFixedArray(int length) {
+  if (length < 0 || length > FixedArray::kMaxLength) {
+    return Failure::OutOfMemoryException();
+  }
   // Use the general function if we're forced to always allocate.
   if (always_allocate()) return AllocateFixedArray(length, TENURED);
   // Allocate the raw data for a fixed array.
@@ -2820,29 +2907,47 @@
 
 
 Object* Heap::AllocateFixedArray(int length, PretenureFlag pretenure) {
+  ASSERT(length >= 0);
   ASSERT(empty_fixed_array()->IsFixedArray());
+  if (length < 0 || length > FixedArray::kMaxLength) {
+    return Failure::OutOfMemoryException();
+  }
   if (length == 0) return empty_fixed_array();
 
-  // New space can't cope with forced allocation.
-  if (always_allocate()) pretenure = TENURED;
-
+  AllocationSpace space =
+      (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   int size = FixedArray::SizeFor(length);
+  if (space == NEW_SPACE && size > kMaxObjectSizeInNewSpace) {
+    // Too big for new space.
+    space = LO_SPACE;
+  } else if (space == OLD_POINTER_SPACE &&
+             size > MaxObjectSizeInPagedSpace()) {
+    // Too big for old pointer space.
+    space = LO_SPACE;
+  }
+
+  // Specialize allocation for the space.
   Object* result = Failure::OutOfMemoryException();
-  if (pretenure != TENURED) {
-    result = size <= kMaxObjectSizeInNewSpace
-        ? new_space_.AllocateRaw(size)
-        : lo_space_->AllocateRawFixedArray(size);
-  }
-  if (result->IsFailure()) {
-    if (size > MaxObjectSizeInPagedSpace()) {
-      result = lo_space_->AllocateRawFixedArray(size);
-    } else {
-      AllocationSpace space =
-          (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
-      result = AllocateRaw(size, space, OLD_POINTER_SPACE);
+  if (space == NEW_SPACE) {
+    // We cannot use Heap::AllocateRaw() because it will not properly
+    // allocate extra remembered set bits if always_allocate() is true and
+    // new space allocation fails.
+    result = new_space_.AllocateRaw(size);
+    if (result->IsFailure() && always_allocate()) {
+      if (size <= MaxObjectSizeInPagedSpace()) {
+        result = old_pointer_space_->AllocateRaw(size);
+      } else {
+        result = lo_space_->AllocateRawFixedArray(size);
+      }
     }
-    if (result->IsFailure()) return result;
+  } else if (space == OLD_POINTER_SPACE) {
+    result = old_pointer_space_->AllocateRaw(size);
+  } else {
+    ASSERT(space == LO_SPACE);
+    result = lo_space_->AllocateRawFixedArray(size);
   }
+  if (result->IsFailure()) return result;
+
   // Initialize the object.
   reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
   FixedArray* array = FixedArray::cast(result);
@@ -3437,7 +3542,10 @@
   if (!code_space_->Setup(NULL, 0)) return false;
 
   // Initialize map space.
-  map_space_ = new MapSpace(kMaxMapSpaceSize, MAP_SPACE);
+  map_space_ = new MapSpace(FLAG_use_big_map_space
+      ? max_old_generation_size_
+      : (MapSpace::kMaxMapPageIndex + 1) * Page::kPageSize,
+      MAP_SPACE);
   if (map_space_ == NULL) return false;
   if (!map_space_->Setup(NULL, 0)) return false;
 
diff --git a/src/heap.h b/src/heap.h
index fdc04a8..1f04444 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -269,7 +269,7 @@
     return reinterpret_cast<Address>(&always_allocate_scope_depth_);
   }
   static bool linear_allocation() {
-      return linear_allocation_scope_depth_ != 0;
+    return linear_allocation_scope_depth_ != 0;
   }
 
   static Address* NewSpaceAllocationTopAddress() {
@@ -804,9 +804,27 @@
   // Rebuild remembered set in old and map spaces.
   static void RebuildRSets();
 
+  // Update an old object's remembered set
+  static int UpdateRSet(HeapObject* obj);
+
   // Commits from space if it is uncommitted.
   static void EnsureFromSpaceIsCommitted();
 
+  // Support for partial snapshots.  After calling this we can allocate a
+  // certain number of bytes using only linear allocation (with a
+  // LinearAllocationScope and an AlwaysAllocateScope) without using freelists
+  // or causing a GC.  It returns true of space was reserved or false if a GC is
+  // needed.  For paged spaces the space requested must include the space wasted
+  // at the end of each page when allocating linearly.
+  static void ReserveSpace(
+    int new_space_size,
+    int pointer_space_size,
+    int data_space_size,
+    int code_space_size,
+    int map_space_size,
+    int cell_space_size,
+    int large_object_size);
+
   //
   // Support for the API.
   //
@@ -820,9 +838,6 @@
   // Update the cache with a new number-string pair.
   static void SetNumberStringCache(Object* number, String* str);
 
-  // Entries in the cache.  Must be a power of 2.
-  static const int kNumberStringCacheSize = 64;
-
   // Adjusts the amount of registered external memory.
   // Returns the adjusted value.
   static inline int AdjustAmountOfExternalAllocatedMemory(int change_in_bytes);
@@ -837,11 +852,15 @@
            > old_gen_promotion_limit_;
   }
 
+  static intptr_t OldGenerationSpaceAvailable() {
+    return old_gen_allocation_limit_ -
+           (PromotedSpaceSize() + PromotedExternalMemorySize());
+  }
+
   // True if we have reached the allocation limit in the old generation that
   // should artificially cause a GC right now.
   static bool OldGenerationAllocationLimitReached() {
-    return (PromotedSpaceSize() + PromotedExternalMemorySize())
-           > old_gen_allocation_limit_;
+    return OldGenerationSpaceAvailable() < 0;
   }
 
   // Can be called when the embedding application is idle.
@@ -890,11 +909,6 @@
   static int linear_allocation_scope_depth_;
   static bool context_disposed_pending_;
 
-  // The number of MapSpace pages is limited by the way we pack
-  // Map pointers during GC.
-  static const int kMaxMapSpaceSize =
-      (1 << (MapWord::kMapPageIndexBits)) * Page::kPageSize;
-
 #if defined(V8_TARGET_ARCH_X64)
   static const int kMaxObjectSizeInNewSpace = 512*KB;
 #else
@@ -1060,9 +1074,9 @@
   // Helper function used by CopyObject to copy a source object to an
   // allocated target object and update the forwarding pointer in the source
   // object.  Returns the target object.
-  static HeapObject* MigrateObject(HeapObject* source,
-                                   HeapObject* target,
-                                   int size);
+  static inline HeapObject* MigrateObject(HeapObject* source,
+                                          HeapObject* target,
+                                          int size);
 
   // Helper function that governs the promotion policy from new space to
   // old.  If the object's old address lies below the new space's age
@@ -1078,9 +1092,6 @@
   static void ReportStatisticsAfterGC();
 #endif
 
-  // Update an old object's remembered set
-  static int UpdateRSet(HeapObject* obj);
-
   // Rebuild remembered set in an old space.
   static void RebuildRSets(PagedSpace* space);
 
@@ -1103,6 +1114,12 @@
                                            SharedFunctionInfo* shared,
                                            Object* prototype);
 
+
+  // Initializes the number to string cache based on the max semispace size.
+  static Object* InitializeNumberStringCache();
+  // Flush the number to string cache.
+  static void FlushNumberStringCache();
+
   static const int kInitialSymbolTableSize = 2048;
   static const int kInitialEvalCacheSize = 64;
 
@@ -1234,7 +1251,7 @@
 
 
 // Space iterator for iterating over all the paged spaces of the heap:
-// Map space, old pointer space, old data space and code space.
+// Map space, old pointer space, old data space, code space and cell space.
 // Returns each space in turn, and null when it is done.
 class PagedSpaces BASE_EMBEDDED {
  public:
diff --git a/src/ia32/assembler-ia32.cc b/src/ia32/assembler-ia32.cc
index a0236d0..0e9ffea 100644
--- a/src/ia32/assembler-ia32.cc
+++ b/src/ia32/assembler-ia32.cc
@@ -575,6 +575,7 @@
 
 
 void Assembler::mov_b(Register dst, const Operand& src) {
+  ASSERT(dst.code() < 4);
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   EMIT(0x8A);
@@ -592,6 +593,7 @@
 
 
 void Assembler::mov_b(const Operand& dst, Register src) {
+  ASSERT(src.code() < 4);
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
   EMIT(0x88);
@@ -752,6 +754,14 @@
 }
 
 
+void Assembler::rep_movs() {
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0xF3);
+  EMIT(0xA5);
+}
+
+
 void Assembler::xchg(Register dst, Register src) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
@@ -1199,6 +1209,15 @@
 }
 
 
+void Assembler::subb(Register dst, const Operand& src) {
+  ASSERT(dst.code() < 4);
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0x2A);
+  emit_operand(dst, src);
+}
+
+
 void Assembler::sub(const Operand& dst, Register src) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
@@ -1586,7 +1605,6 @@
 
 // FPU instructions
 
-
 void Assembler::fld(int i) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
@@ -1675,6 +1693,15 @@
 }
 
 
+void Assembler::fisttp_d(const Operand& adr) {
+  ASSERT(CpuFeatures::IsEnabled(SSE3));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0xDD);
+  emit_operand(ecx, adr);
+}
+
+
 void Assembler::fist_s(const Operand& adr) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
@@ -2026,6 +2053,50 @@
 }
 
 
+void Assembler::movdqa(const Operand& dst, XMMRegister src ) {
+  ASSERT(CpuFeatures::IsEnabled(SSE2));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0x66);
+  EMIT(0x0F);
+  EMIT(0x7F);
+  emit_sse_operand(src, dst);
+}
+
+
+void Assembler::movdqa(XMMRegister dst, const Operand& src) {
+  ASSERT(CpuFeatures::IsEnabled(SSE2));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0x66);
+  EMIT(0x0F);
+  EMIT(0x6F);
+  emit_sse_operand(dst, src);
+}
+
+
+void Assembler::movdqu(const Operand& dst, XMMRegister src ) {
+  ASSERT(CpuFeatures::IsEnabled(SSE2));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0xF3);
+  EMIT(0x0F);
+  EMIT(0x7F);
+  emit_sse_operand(src, dst);
+}
+
+
+void Assembler::movdqu(XMMRegister dst, const Operand& src) {
+  ASSERT(CpuFeatures::IsEnabled(SSE2));
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  EMIT(0xF3);
+  EMIT(0x0F);
+  EMIT(0x6F);
+  emit_sse_operand(dst, src);
+}
+
+
 void Assembler::movdbl(XMMRegister dst, const Operand& src) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index 21fa0d5..f35abd5 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -540,6 +540,9 @@
   void cmov(Condition cc, Register dst, Handle<Object> handle);
   void cmov(Condition cc, Register dst, const Operand& src);
 
+  // Repetitive string instructions.
+  void rep_movs();
+
   // Exchange two registers
   void xchg(Register dst, Register src);
 
@@ -614,6 +617,7 @@
   void shr_cl(Register dst);
 
   void subb(const Operand& dst, int8_t imm8);
+  void subb(Register dst, const Operand& src);
   void sub(const Operand& dst, const Immediate& x);
   void sub(Register dst, const Operand& src);
   void sub(const Operand& dst, Register src);
@@ -693,6 +697,7 @@
   void fistp_d(const Operand& adr);
 
   void fisttp_s(const Operand& adr);
+  void fisttp_d(const Operand& adr);
 
   void fabs();
   void fchs();
@@ -749,6 +754,11 @@
 
   void comisd(XMMRegister dst, XMMRegister src);
 
+  void movdqa(XMMRegister dst, const Operand& src);
+  void movdqa(const Operand& dst, XMMRegister src);
+  void movdqu(XMMRegister dst, const Operand& src);
+  void movdqu(const Operand& dst, XMMRegister src);
+
   // Use either movsd or movlpd.
   void movdbl(XMMRegister dst, const Operand& src);
   void movdbl(const Operand& dst, XMMRegister src);
diff --git a/src/ia32/builtins-ia32.cc b/src/ia32/builtins-ia32.cc
index f4dd2f9..d56c02d 100644
--- a/src/ia32/builtins-ia32.cc
+++ b/src/ia32/builtins-ia32.cc
@@ -86,7 +86,7 @@
   __ EnterConstructFrame();
 
   // Store a smi-tagged arguments count on the stack.
-  __ shl(eax, kSmiTagSize);
+  __ SmiTag(eax);
   __ push(eax);
 
   // Push the function to invoke on the stack.
@@ -255,7 +255,7 @@
 
   // Retrieve smi-tagged arguments count from the stack.
   __ mov(eax, Operand(esp, 0));
-  __ shr(eax, kSmiTagSize);
+  __ SmiUntag(eax);
 
   // Push the allocated receiver to the stack. We need two copies
   // because we may have to return the original one and the calling
@@ -440,8 +440,7 @@
     __ EnterInternalFrame();  // preserves eax, ebx, edi
 
     // Store the arguments count on the stack (smi tagged).
-    ASSERT(kSmiTag == 0);
-    __ shl(eax, kSmiTagSize);
+    __ SmiTag(eax);
     __ push(eax);
 
     __ push(edi);  // save edi across the call
@@ -452,7 +451,7 @@
 
     // Get the arguments count and untag it.
     __ pop(eax);
-    __ shr(eax, kSmiTagSize);
+    __ SmiUntag(eax);
 
     __ LeaveInternalFrame();
     __ jmp(&patch_receiver);
@@ -634,7 +633,7 @@
 
   // Invoke the function.
   ParameterCount actual(eax);
-  __ shr(eax, kSmiTagSize);
+  __ SmiUntag(eax);
   __ mov(edi, Operand(ebp, 4 * kPointerSize));
   __ InvokeFunction(edi, actual, CALL_FUNCTION);
 
@@ -831,7 +830,7 @@
   // elements_array_end: start of next object
   // array_size: size of array (smi)
   ASSERT(kSmiTag == 0);
-  __ shr(array_size, kSmiTagSize);  // Convert from smi to value.
+  __ SmiUntag(array_size);  // Convert from smi to value.
   __ mov(FieldOperand(elements_array, JSObject::kMapOffset),
          Factory::fixed_array_map());
   Label not_empty_2, fill_array;
@@ -960,7 +959,7 @@
   // Handle construction of an array from a list of arguments.
   __ bind(&argc_two_or_more);
   ASSERT(kSmiTag == 0);
-  __ shl(eax, kSmiTagSize);  // Convet argc to a smi.
+  __ SmiTag(eax);  // Convet argc to a smi.
   // eax: array_size (smi)
   // edi: constructor
   // esp[0] : argc
diff --git a/src/ia32/codegen-ia32-inl.h b/src/ia32/codegen-ia32-inl.h
index 44e937a..49c706d 100644
--- a/src/ia32/codegen-ia32-inl.h
+++ b/src/ia32/codegen-ia32-inl.h
@@ -39,16 +39,6 @@
 void DeferredCode::Jump() { __ jmp(&entry_label_); }
 void DeferredCode::Branch(Condition cc) { __ j(cc, &entry_label_); }
 
-void CodeGenerator::GenerateMathSin(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(SIN, args);
-}
-
-
-void CodeGenerator::GenerateMathCos(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(COS, args);
-}
-
-
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/ia32/codegen-ia32.cc b/src/ia32/codegen-ia32.cc
index 2494686..993675b 100644
--- a/src/ia32/codegen-ia32.cc
+++ b/src/ia32/codegen-ia32.cc
@@ -32,7 +32,10 @@
 #include "compiler.h"
 #include "debug.h"
 #include "ic-inl.h"
+#include "jsregexp.h"
 #include "parser.h"
+#include "regexp-macro-assembler.h"
+#include "regexp-stack.h"
 #include "register-allocator-inl.h"
 #include "runtime.h"
 #include "scopes.h"
@@ -248,6 +251,12 @@
       StoreArgumentsObject(true);
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      frame_->Push(Factory::the_hole_value());
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.
@@ -600,36 +609,33 @@
     frame_->Push(&result);
   }
 
-  { Reference shadow_ref(this, scope_->arguments_shadow());
-    Reference arguments_ref(this, scope_->arguments());
-    ASSERT(shadow_ref.is_slot() && arguments_ref.is_slot());
-    // Here we rely on the convenient property that references to slot
-    // take up zero space in the frame (ie, it doesn't matter that the
-    // stored value is actually below the reference on the frame).
-    JumpTarget done;
-    bool skip_arguments = false;
-    if (mode == LAZY_ARGUMENTS_ALLOCATION && !initial) {
-      // We have to skip storing into the arguments slot if it has
-      // already been written to. This can happen if the a function
-      // has a local variable named 'arguments'.
-      LoadFromSlot(scope_->arguments()->var()->slot(), NOT_INSIDE_TYPEOF);
-      Result arguments = frame_->Pop();
-      if (arguments.is_constant()) {
-        // We have to skip updating the arguments object if it has
-        // been assigned a proper value.
-        skip_arguments = !arguments.handle()->IsTheHole();
-      } else {
-        __ cmp(Operand(arguments.reg()), Immediate(Factory::the_hole_value()));
-        arguments.Unuse();
-        done.Branch(not_equal);
-      }
+  Variable* arguments = scope_->arguments()->var();
+  Variable* shadow = scope_->arguments_shadow()->var();
+  ASSERT(arguments != NULL && arguments->slot() != NULL);
+  ASSERT(shadow != NULL && shadow->slot() != NULL);
+  JumpTarget done;
+  bool skip_arguments = false;
+  if (mode == LAZY_ARGUMENTS_ALLOCATION && !initial) {
+    // We have to skip storing into the arguments slot if it has already
+    // been written to. This can happen if the a function has a local
+    // variable named 'arguments'.
+    LoadFromSlot(arguments->slot(), NOT_INSIDE_TYPEOF);
+    Result probe = frame_->Pop();
+    if (probe.is_constant()) {
+      // We have to skip updating the arguments object if it has
+      // been assigned a proper value.
+      skip_arguments = !probe.handle()->IsTheHole();
+    } else {
+      __ cmp(Operand(probe.reg()), Immediate(Factory::the_hole_value()));
+      probe.Unuse();
+      done.Branch(not_equal);
     }
-    if (!skip_arguments) {
-      arguments_ref.SetValue(NOT_CONST_INIT);
-      if (mode == LAZY_ARGUMENTS_ALLOCATION) done.Bind();
-    }
-    shadow_ref.SetValue(NOT_CONST_INIT);
   }
+  if (!skip_arguments) {
+    StoreToSlot(arguments->slot(), NOT_CONST_INIT);
+    if (mode == LAZY_ARGUMENTS_ALLOCATION) done.Bind();
+  }
+  StoreToSlot(shadow->slot(), NOT_CONST_INIT);
   return frame_->Pop();
 }
 
@@ -661,15 +667,7 @@
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     Load(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       Load(property->key());
@@ -761,6 +759,11 @@
   static void CheckFloatOperands(MacroAssembler* masm,
                                  Label* non_float,
                                  Register scratch);
+  // Takes the operands in edx and eax and loads them as integers in eax
+  // and ecx.
+  static void LoadAsIntegers(MacroAssembler* masm,
+                             bool use_sse3,
+                             Label* operand_conversion_failure);
   // Test if operands are numbers (smi or HeapNumber objects), and load
   // them into xmm0 and xmm1 if they are.  Jump to label not_numbers if
   // either operand is not a number.  Operands are in edx and eax.
@@ -771,8 +774,8 @@
 
 const char* GenericBinaryOpStub::GetName() {
   if (name_ != NULL) return name_;
-  const int len = 100;
-  name_ = Bootstrapper::AllocateAutoDeletedArray(len);
+  const int kMaxNameLength = 100;
+  name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);
   if (name_ == NULL) return "OOM";
   const char* op_name = Token::Name(op_);
   const char* overwrite_name;
@@ -783,7 +786,7 @@
     default: overwrite_name = "UnknownOverwrite"; break;
   }
 
-  OS::SNPrintF(Vector<char>(name_, len),
+  OS::SNPrintF(Vector<char>(name_, kMaxNameLength),
                "GenericBinaryOpStub_%s_%s%s_%s%s",
                op_name,
                overwrite_name,
@@ -838,9 +841,9 @@
     __ jmp(&load_right);
 
     __ bind(&left_smi);
-    __ sar(left_, 1);
+    __ SmiUntag(left_);
     __ cvtsi2sd(xmm0, Operand(left_));
-    __ shl(left_, 1);
+    __ SmiTag(left_);
     if (mode_ == OVERWRITE_LEFT) {
       Label alloc_failure;
       __ push(left_);
@@ -866,9 +869,9 @@
     __ jmp(&do_op);
 
     __ bind(&right_smi);
-    __ sar(right_, 1);
+    __ SmiUntag(right_);
     __ cvtsi2sd(xmm1, Operand(right_));
-    __ shl(right_, 1);
+    __ SmiTag(right_);
     if (mode_ == OVERWRITE_RIGHT || mode_ == NO_OVERWRITE) {
       Label alloc_failure;
       __ push(left_);
@@ -1211,8 +1214,7 @@
       __ test(edx, Operand(edx));
       deferred->Branch(not_zero);
       // Tag the result and store it in the quotient register.
-      ASSERT(kSmiTagSize == times_2);  // adjust code if not the case
-      __ lea(eax, Operand(eax, eax, times_1, kSmiTag));
+      __ SmiTag(eax);
       deferred->BindExit();
       left->Unuse();
       right->Unuse();
@@ -1272,8 +1274,8 @@
 
     // Untag both operands.
     __ mov(answer.reg(), left->reg());
-    __ sar(answer.reg(), kSmiTagSize);
-    __ sar(ecx, kSmiTagSize);
+    __ SmiUntag(answer.reg());
+    __ SmiUntag(ecx);
     // Perform the operation.
     switch (op) {
       case Token::SAR:
@@ -1295,8 +1297,7 @@
         // in a case where it is dropped anyway.
         __ test(answer.reg(), Immediate(0xc0000000));
         __ j(zero, &result_ok);
-        ASSERT(kSmiTag == 0);
-        __ shl(ecx, kSmiTagSize);
+        __ SmiTag(ecx);
         deferred->Jump();
         __ bind(&result_ok);
         break;
@@ -1307,8 +1308,7 @@
         // Check that the *signed* result fits in a smi.
         __ cmp(answer.reg(), 0xc0000000);
         __ j(positive, &result_ok);
-        ASSERT(kSmiTag == 0);
-        __ shl(ecx, kSmiTagSize);
+        __ SmiTag(ecx);
         deferred->Jump();
         __ bind(&result_ok);
         break;
@@ -1317,9 +1317,7 @@
         UNREACHABLE();
     }
     // Smi-tag the result in answer.
-    ASSERT(kSmiTagSize == 1);  // Adjust code if not the case.
-    __ lea(answer.reg(),
-           Operand(answer.reg(), answer.reg(), times_1, kSmiTag));
+    __ SmiTag(answer.reg());
     deferred->BindExit();
     left->Unuse();
     right->Unuse();
@@ -1369,7 +1367,7 @@
       ASSERT(kSmiTag == 0);  // Adjust code below if not the case.
       // Remove smi tag from the left operand (but keep sign).
       // Left-hand operand has been copied into answer.
-      __ sar(answer.reg(), kSmiTagSize);
+      __ SmiUntag(answer.reg());
       // Do multiplication of smis, leaving result in answer.
       __ imul(answer.reg(), Operand(right->reg()));
       // Go slow on overflows.
@@ -1716,7 +1714,7 @@
         __ test(operand->reg(), Immediate(kSmiTagMask));
         deferred->Branch(not_zero);
         __ mov(answer.reg(), operand->reg());
-        __ sar(answer.reg(), kSmiTagSize);
+        __ SmiUntag(answer.reg());
         __ shr(answer.reg(), shift_value);
         // A negative Smi shifted right two is in the positive Smi range.
         if (shift_value < 2) {
@@ -1724,9 +1722,7 @@
           deferred->Branch(not_zero);
         }
         operand->Unuse();
-        ASSERT(kSmiTagSize == times_2);  // Adjust the code if not true.
-        __ lea(answer.reg(),
-               Operand(answer.reg(), answer.reg(), times_1, kSmiTag));
+        __ SmiTag(answer.reg());
         deferred->BindExit();
         frame_->Push(&answer);
       }
@@ -1734,9 +1730,42 @@
 
     case Token::SHL:
       if (reversed) {
-        Result constant_operand(value);
-        LikelySmiBinaryOperation(op, &constant_operand, operand,
-                                 overwrite_mode);
+        Result right;
+        Result right_copy_in_ecx;
+
+        // Make sure to get a copy of the right operand into ecx. This
+        // allows us to modify it without having to restore it in the
+        // deferred code.
+        operand->ToRegister();
+        if (operand->reg().is(ecx)) {
+          right = allocator()->Allocate();
+          __ mov(right.reg(), ecx);
+          frame_->Spill(ecx);
+          right_copy_in_ecx = *operand;
+        } else {
+          right_copy_in_ecx = allocator()->Allocate(ecx);
+          __ mov(ecx, operand->reg());
+          right = *operand;
+        }
+        operand->Unuse();
+
+        Result answer = allocator()->Allocate();
+        DeferredInlineSmiOperationReversed* deferred =
+            new DeferredInlineSmiOperationReversed(op,
+                                                   answer.reg(),
+                                                   smi_value,
+                                                   right.reg(),
+                                                   overwrite_mode);
+        __ mov(answer.reg(), Immediate(int_value));
+        __ sar(ecx, kSmiTagSize);
+        deferred->Branch(carry);
+        __ shl_cl(answer.reg());
+        __ cmp(answer.reg(), 0xc0000000);
+        deferred->Branch(sign);
+        __ SmiTag(answer.reg());
+
+        deferred->BindExit();
+        frame_->Push(&answer);
       } else {
         // Only the least significant 5 bits of the shift value are used.
         // In the slow case, this masking is done inside the runtime call.
@@ -1865,6 +1894,13 @@
 }
 
 
+static bool CouldBeNaN(const Result& result) {
+  if (!result.is_constant()) return true;
+  if (!result.handle()->IsHeapNumber()) return false;
+  return isnan(HeapNumber::cast(*result.handle())->value());
+}
+
+
 void CodeGenerator::Comparison(AstNode* node,
                                Condition cc,
                                bool strict,
@@ -1885,15 +1921,28 @@
   }
   ASSERT(cc == less || cc == equal || cc == greater_equal);
 
-  // If either side is a constant smi, optimize the comparison.
-  bool left_side_constant_smi =
-      left_side.is_constant() && left_side.handle()->IsSmi();
-  bool right_side_constant_smi =
-      right_side.is_constant() && right_side.handle()->IsSmi();
-  bool left_side_constant_null =
-      left_side.is_constant() && left_side.handle()->IsNull();
-  bool right_side_constant_null =
-      right_side.is_constant() && right_side.handle()->IsNull();
+  // If either side is a constant of some sort, we can probably optimize the
+  // comparison.
+  bool left_side_constant_smi = false;
+  bool left_side_constant_null = false;
+  bool left_side_constant_1_char_string = false;
+  if (left_side.is_constant()) {
+    left_side_constant_smi = left_side.handle()->IsSmi();
+    left_side_constant_null = left_side.handle()->IsNull();
+    left_side_constant_1_char_string =
+        (left_side.handle()->IsString() &&
+         (String::cast(*left_side.handle())->length() == 1));
+  }
+  bool right_side_constant_smi = false;
+  bool right_side_constant_null = false;
+  bool right_side_constant_1_char_string = false;
+  if (right_side.is_constant()) {
+    right_side_constant_smi = right_side.handle()->IsSmi();
+    right_side_constant_null = right_side.handle()->IsNull();
+    right_side_constant_1_char_string =
+        (right_side.handle()->IsString() &&
+         (String::cast(*right_side.handle())->length() == 1));
+  }
 
   if (left_side_constant_smi || right_side_constant_smi) {
     if (left_side_constant_smi && right_side_constant_smi) {
@@ -1982,7 +2031,7 @@
       }
 
       // Setup and call the compare stub.
-      CompareStub stub(cc, strict);
+      CompareStub stub(cc, strict, kCantBothBeNaN);
       Result result = frame_->CallStub(&stub, &left_side, &right_side);
       result.ToRegister();
       __ cmp(result.reg(), 0);
@@ -2041,18 +2090,153 @@
       operand.Unuse();
       dest->Split(not_zero);
     }
+  } else if (left_side_constant_1_char_string ||
+             right_side_constant_1_char_string) {
+    if (left_side_constant_1_char_string && right_side_constant_1_char_string) {
+      // Trivial case, comparing two constants.
+      int left_value = String::cast(*left_side.handle())->Get(0);
+      int right_value = String::cast(*right_side.handle())->Get(0);
+      switch (cc) {
+        case less:
+          dest->Goto(left_value < right_value);
+          break;
+        case equal:
+          dest->Goto(left_value == right_value);
+          break;
+        case greater_equal:
+          dest->Goto(left_value >= right_value);
+          break;
+        default:
+          UNREACHABLE();
+      }
+    } else {
+      // Only one side is a constant 1 character string.
+      // If left side is a constant 1-character string, reverse the operands.
+      // Since one side is a constant string, conversion order does not matter.
+      if (left_side_constant_1_char_string) {
+        Result temp = left_side;
+        left_side = right_side;
+        right_side = temp;
+        cc = ReverseCondition(cc);
+        // This may reintroduce greater or less_equal as the value of cc.
+        // CompareStub and the inline code both support all values of cc.
+      }
+      // Implement comparison against a constant string, inlining the case
+      // where both sides are strings.
+      left_side.ToRegister();
+
+      // Here we split control flow to the stub call and inlined cases
+      // before finally splitting it to the control destination.  We use
+      // a jump target and branching to duplicate the virtual frame at
+      // the first split.  We manually handle the off-frame references
+      // by reconstituting them on the non-fall-through path.
+      JumpTarget is_not_string, is_string;
+      Register left_reg = left_side.reg();
+      Handle<Object> right_val = right_side.handle();
+      __ test(left_side.reg(), Immediate(kSmiTagMask));
+      is_not_string.Branch(zero, &left_side);
+      Result temp = allocator_->Allocate();
+      ASSERT(temp.is_valid());
+      __ mov(temp.reg(),
+             FieldOperand(left_side.reg(), HeapObject::kMapOffset));
+      __ movzx_b(temp.reg(),
+                 FieldOperand(temp.reg(), Map::kInstanceTypeOffset));
+      // If we are testing for equality then make use of the symbol shortcut.
+      // Check if the right left hand side has the same type as the left hand
+      // side (which is always a symbol).
+      if (cc == equal) {
+        Label not_a_symbol;
+        ASSERT(kSymbolTag != 0);
+        // Ensure that no non-strings have the symbol bit set.
+        ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
+        __ test(temp.reg(), Immediate(kIsSymbolMask));  // Test the symbol bit.
+        __ j(zero, &not_a_symbol);
+        // They are symbols, so do identity compare.
+        __ cmp(left_side.reg(), right_side.handle());
+        dest->true_target()->Branch(equal);
+        dest->false_target()->Branch(not_equal);
+        __ bind(&not_a_symbol);
+      }
+      // If the receiver is not a string of the type we handle call the stub.
+      __ and_(temp.reg(),
+          kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask);
+      __ cmp(temp.reg(), kStringTag | kSeqStringTag | kAsciiStringTag);
+      temp.Unuse();
+      is_string.Branch(equal, &left_side);
+
+      // Setup and call the compare stub.
+      is_not_string.Bind(&left_side);
+      CompareStub stub(cc, strict, kCantBothBeNaN);
+      Result result = frame_->CallStub(&stub, &left_side, &right_side);
+      result.ToRegister();
+      __ cmp(result.reg(), 0);
+      result.Unuse();
+      dest->true_target()->Branch(cc);
+      dest->false_target()->Jump();
+
+      is_string.Bind(&left_side);
+      // Here we know we have a sequential ASCII string.
+      left_side = Result(left_reg);
+      right_side = Result(right_val);
+      Result temp2 = allocator_->Allocate();
+      ASSERT(temp2.is_valid());
+      // Test string equality and comparison.
+      if (cc == equal) {
+        Label comparison_done;
+        __ cmp(FieldOperand(left_side.reg(), String::kLengthOffset),
+               Immediate(1));
+        __ j(not_equal, &comparison_done);
+        uint8_t char_value =
+            static_cast<uint8_t>(String::cast(*right_side.handle())->Get(0));
+        __ cmpb(FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize),
+                char_value);
+        __ bind(&comparison_done);
+      } else {
+        __ mov(temp2.reg(),
+               FieldOperand(left_side.reg(), String::kLengthOffset));
+        __ sub(Operand(temp2.reg()), Immediate(1));
+        Label comparison;
+        // If the length is 0 then our subtraction gave -1 which compares less
+        // than any character.
+        __ j(negative, &comparison);
+        // Otherwise load the first character.
+        __ movzx_b(temp2.reg(),
+                   FieldOperand(left_side.reg(), SeqAsciiString::kHeaderSize));
+        __ bind(&comparison);
+        // Compare the first character of the string with out constant
+        // 1-character string.
+        uint8_t char_value =
+            static_cast<uint8_t>(String::cast(*right_side.handle())->Get(0));
+        __ cmp(Operand(temp2.reg()), Immediate(char_value));
+        Label characters_were_different;
+        __ j(not_equal, &characters_were_different);
+        // If the first character is the same then the long string sorts after
+        // the short one.
+        __ cmp(FieldOperand(left_side.reg(), String::kLengthOffset),
+               Immediate(1));
+        __ bind(&characters_were_different);
+      }
+      temp2.Unuse();
+      left_side.Unuse();
+      right_side.Unuse();
+      dest->Split(cc);
+    }
   } else {
     // Neither side is a constant Smi or null.
     // If either side is a non-smi constant, skip the smi check.
     bool known_non_smi =
         (left_side.is_constant() && !left_side.handle()->IsSmi()) ||
         (right_side.is_constant() && !right_side.handle()->IsSmi());
+    NaNInformation nan_info =
+        (CouldBeNaN(left_side) && CouldBeNaN(right_side)) ?
+        kBothCouldBeNaN :
+        kCantBothBeNaN;
     left_side.ToRegister();
     right_side.ToRegister();
 
     if (known_non_smi) {
       // When non-smi, call out to the compare stub.
-      CompareStub stub(cc, strict);
+      CompareStub stub(cc, strict, nan_info);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
       if (cc == equal) {
         __ test(answer.reg(), Operand(answer.reg()));
@@ -2079,7 +2263,7 @@
       temp.Unuse();
       is_smi.Branch(zero, taken);
       // When non-smi, call out to the compare stub.
-      CompareStub stub(cc, strict);
+      CompareStub stub(cc, strict, nan_info);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
       if (cc == equal) {
         __ test(answer.reg(), Operand(answer.reg()));
@@ -2239,7 +2423,7 @@
     __ bind(&adapted);
     static const uint32_t kArgumentsLimit = 1 * KB;
     __ mov(eax, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
-    __ shr(eax, kSmiTagSize);
+    __ SmiUntag(eax);
     __ mov(ecx, Operand(eax));
     __ cmp(eax, kArgumentsLimit);
     build_args.Branch(above);
@@ -3266,7 +3450,7 @@
   frame_->EmitPush(eax);  // <- slot 3
   frame_->EmitPush(edx);  // <- slot 2
   __ mov(eax, FieldOperand(edx, FixedArray::kLengthOffset));
-  __ shl(eax, kSmiTagSize);
+  __ SmiTag(eax);
   frame_->EmitPush(eax);  // <- slot 1
   frame_->EmitPush(Immediate(Smi::FromInt(0)));  // <- slot 0
   entry.Jump();
@@ -3278,7 +3462,7 @@
 
   // Push the length of the array and the initial index onto the stack.
   __ mov(eax, FieldOperand(eax, FixedArray::kLengthOffset));
-  __ shl(eax, kSmiTagSize);
+  __ SmiTag(eax);
   frame_->EmitPush(eax);  // <- slot 1
   frame_->EmitPush(Immediate(Smi::FromInt(0)));  // <- slot 0
 
@@ -3394,13 +3578,9 @@
   frame_->EmitPush(eax);
 
   // Store the caught exception in the catch variable.
-  { Reference ref(this, node->catch_var());
-    ASSERT(ref.is_slot());
-    // Load the exception to the top of the stack.  Here we make use of the
-    // convenient property that it doesn't matter whether a value is
-    // immediately on top of or underneath a zero-sized reference.
-    ref.SetValue(NOT_CONST_INIT);
-  }
+  Variable* catch_var = node->catch_var()->var();
+  ASSERT(catch_var != NULL && catch_var->slot() != NULL);
+  StoreToSlot(catch_var->slot(), NOT_CONST_INIT);
 
   // Remove the exception from the stack.
   frame_->Drop();
@@ -3721,21 +3901,21 @@
 void CodeGenerator::InstantiateBoilerplate(Handle<JSFunction> boilerplate) {
   ASSERT(boilerplate->IsBoilerplate());
 
+  // The inevitable call will sync frame elements to memory anyway, so
+  // we do it eagerly to allow us to push the arguments directly into
+  // place.
+  frame_->SyncRange(0, frame_->element_count() - 1);
+
   // Use the fast case closure allocation code that allocates in new
   // space for nested functions that don't need literals cloning.
   if (scope()->is_function_scope() && boilerplate->NumberOfLiterals() == 0) {
     FastNewClosureStub stub;
-    frame_->Push(boilerplate);
+    frame_->EmitPush(Immediate(boilerplate));
     Result answer = frame_->CallStub(&stub, 1);
     frame_->Push(&answer);
   } else {
     // Call the runtime to instantiate the function boilerplate
-    // object.  The inevitable call will sync frame elements to memory
-    // anyway, so we do it eagerly to allow us to push the arguments
-    // directly into place.
-    frame_->SyncRange(0, frame_->element_count() - 1);
-
-    // Create a new closure.
+    // object.
     frame_->EmitPush(esi);
     frame_->EmitPush(Immediate(boilerplate));
     Result result = frame_->CallRuntime(Runtime::kNewClosure, 2);
@@ -4238,46 +4418,10 @@
 }
 
 
-// Materialize the object literal 'node' in the literals array
-// 'literals' of the function.  Leave the object boilerplate in
-// 'boilerplate'.
-class DeferredObjectLiteral: public DeferredCode {
- public:
-  DeferredObjectLiteral(Register boilerplate,
-                        Register literals,
-                        ObjectLiteral* node)
-      : boilerplate_(boilerplate), literals_(literals), node_(node) {
-    set_comment("[ DeferredObjectLiteral");
-  }
-
-  void Generate();
-
- private:
-  Register boilerplate_;
-  Register literals_;
-  ObjectLiteral* node_;
-};
-
-
-void DeferredObjectLiteral::Generate() {
-  // Since the entry is undefined we call the runtime system to
-  // compute the literal.
-  // Literal array (0).
-  __ push(literals_);
-  // Literal index (1).
-  __ push(Immediate(Smi::FromInt(node_->literal_index())));
-  // Constant properties (2).
-  __ push(Immediate(node_->constant_properties()));
-  __ CallRuntime(Runtime::kCreateObjectLiteralBoilerplate, 3);
-  if (!boilerplate_.is(eax)) __ mov(boilerplate_, eax);
-}
-
-
 void CodeGenerator::VisitObjectLiteral(ObjectLiteral* node) {
   Comment cmnt(masm_, "[ ObjectLiteral");
 
-  // Retrieve the literals array and check the allocated entry.  Begin
-  // with a writable copy of the function of this activation in a
+  // Load a writable copy of the function of this activation in a
   // register.
   frame_->PushFunction();
   Result literals = frame_->Pop();
@@ -4287,32 +4431,18 @@
   // Load the literals array of the function.
   __ mov(literals.reg(),
          FieldOperand(literals.reg(), JSFunction::kLiteralsOffset));
-
-  // Load the literal at the ast saved index.
-  Result boilerplate = allocator_->Allocate();
-  ASSERT(boilerplate.is_valid());
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ mov(boilerplate.reg(), FieldOperand(literals.reg(), literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code passing the literals array.
-  DeferredObjectLiteral* deferred =
-      new DeferredObjectLiteral(boilerplate.reg(), literals.reg(), node);
-  __ cmp(boilerplate.reg(), Factory::undefined_value());
-  deferred->Branch(equal);
-  deferred->BindExit();
-  literals.Unuse();
-
-  // Push the boilerplate object.
-  frame_->Push(&boilerplate);
-  // Clone the boilerplate object.
-  Runtime::FunctionId clone_function_id = Runtime::kCloneLiteralBoilerplate;
-  if (node->depth() == 1) {
-    clone_function_id = Runtime::kCloneShallowLiteralBoilerplate;
+  // Literal array.
+  frame_->Push(&literals);
+  // Literal index.
+  frame_->Push(Smi::FromInt(node->literal_index()));
+  // Constant properties.
+  frame_->Push(node->constant_properties());
+  Result clone;
+  if (node->depth() > 1) {
+    clone = frame_->CallRuntime(Runtime::kCreateObjectLiteral, 3);
+  } else {
+    clone = frame_->CallRuntime(Runtime::kCreateObjectLiteralShallow, 3);
   }
-  Result clone = frame_->CallRuntime(clone_function_id, 1);
-  // Push the newly cloned literal object as the result.
   frame_->Push(&clone);
 
   for (int i = 0; i < node->properties()->length(); i++) {
@@ -4372,45 +4502,10 @@
 }
 
 
-// Materialize the array literal 'node' in the literals array 'literals'
-// of the function.  Leave the array boilerplate in 'boilerplate'.
-class DeferredArrayLiteral: public DeferredCode {
- public:
-  DeferredArrayLiteral(Register boilerplate,
-                       Register literals,
-                       ArrayLiteral* node)
-      : boilerplate_(boilerplate), literals_(literals), node_(node) {
-    set_comment("[ DeferredArrayLiteral");
-  }
-
-  void Generate();
-
- private:
-  Register boilerplate_;
-  Register literals_;
-  ArrayLiteral* node_;
-};
-
-
-void DeferredArrayLiteral::Generate() {
-  // Since the entry is undefined we call the runtime system to
-  // compute the literal.
-  // Literal array (0).
-  __ push(literals_);
-  // Literal index (1).
-  __ push(Immediate(Smi::FromInt(node_->literal_index())));
-  // Constant properties (2).
-  __ push(Immediate(node_->literals()));
-  __ CallRuntime(Runtime::kCreateArrayLiteralBoilerplate, 3);
-  if (!boilerplate_.is(eax)) __ mov(boilerplate_, eax);
-}
-
-
 void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
   Comment cmnt(masm_, "[ ArrayLiteral");
 
-  // Retrieve the literals array and check the allocated entry.  Begin
-  // with a writable copy of the function of this activation in a
+  // Load a writable copy of the function of this activation in a
   // register.
   frame_->PushFunction();
   Result literals = frame_->Pop();
@@ -4421,36 +4516,19 @@
   __ mov(literals.reg(),
          FieldOperand(literals.reg(), JSFunction::kLiteralsOffset));
 
-  // Load the literal at the ast saved index.
-  Result boilerplate = allocator_->Allocate();
-  ASSERT(boilerplate.is_valid());
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ mov(boilerplate.reg(), FieldOperand(literals.reg(), literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code passing the literals array.
-  DeferredArrayLiteral* deferred =
-      new DeferredArrayLiteral(boilerplate.reg(), literals.reg(), node);
-  __ cmp(boilerplate.reg(), Factory::undefined_value());
-  deferred->Branch(equal);
-  deferred->BindExit();
-  literals.Unuse();
-
-  // Push the resulting array literal boilerplate on the stack.
-  frame_->Push(&boilerplate);
-
-  // Clone the boilerplate object.
+  frame_->Push(&literals);
+  frame_->Push(Smi::FromInt(node->literal_index()));
+  frame_->Push(node->constant_elements());
   int length = node->values()->length();
   Result clone;
-  if (node->depth() == 1 &&
-      length <= FastCloneShallowArrayStub::kMaximumLength) {
-    FastCloneShallowArrayStub stub(length);
-    clone = frame_->CallStub(&stub, 1);
+  if (node->depth() > 1) {
+    clone = frame_->CallRuntime(Runtime::kCreateArrayLiteral, 3);
+  } else if (length > FastCloneShallowArrayStub::kMaximumLength) {
+    clone = frame_->CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   } else {
-    clone = frame_->CallRuntime(Runtime::kCloneLiteralBoilerplate, 1);
+    FastCloneShallowArrayStub stub(length);
+    clone = frame_->CallStub(&stub, 3);
   }
-  // Push the newly cloned literal object as the result.
   frame_->Push(&clone);
 
   // Generate code to set the elements in the array that are not
@@ -4651,22 +4729,19 @@
       frame_->Push(Factory::undefined_value());
     }
 
+    // Push the receiver.
+    frame_->PushParameterAt(-1);
+
     // Resolve the call.
     Result result =
-        frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 2);
+        frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 3);
 
-    // Touch up the stack with the right values for the function and the
-    // receiver.  Use a scratch register to avoid destroying the result.
-    Result scratch = allocator_->Allocate();
-    ASSERT(scratch.is_valid());
-    __ mov(scratch.reg(), FieldOperand(result.reg(), FixedArray::kHeaderSize));
-    frame_->SetElementAt(arg_count + 1, &scratch);
-
-    // We can reuse the result register now.
-    frame_->Spill(result.reg());
-    __ mov(result.reg(),
-           FieldOperand(result.reg(), FixedArray::kHeaderSize + kPointerSize));
-    frame_->SetElementAt(arg_count, &result);
+    // The runtime call returns a pair of values in eax (function) and
+    // edx (receiver). Touch up the stack with the right values.
+    Result receiver = allocator_->Allocate(edx);
+    frame_->SetElementAt(arg_count + 1, &result);
+    frame_->SetElementAt(arg_count, &receiver);
+    receiver.Unuse();
 
     // Call the function.
     CodeForSourcePosition(node->position());
@@ -4966,7 +5041,7 @@
   __ test(index.reg(), Immediate(kSmiTagMask | 0x80000000));
   __ j(not_zero, &slow_case);
   // Untag the index.
-  __ sar(index.reg(), kSmiTagSize);
+  __ SmiUntag(index.reg());
 
   __ bind(&try_again_with_new_string);
   // Fetch the instance type of the receiver into ecx.
@@ -5009,8 +5084,7 @@
                                       times_1,
                                       SeqAsciiString::kHeaderSize));
   __ bind(&got_char_code);
-  ASSERT(kSmiTag == 0);
-  __ shl(temp.reg(), kSmiTagSize);
+  __ SmiTag(temp.reg());
   __ jmp(&end);
 
   // Handle non-flat strings.
@@ -5342,75 +5416,6 @@
 }
 
 
-void CodeGenerator::GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args) {
-  JumpTarget done;
-  JumpTarget call_runtime;
-  ASSERT(args->length() == 1);
-
-  // Load number and duplicate it.
-  Load(args->at(0));
-  frame_->Dup();
-
-  // Get the number into an unaliased register and load it onto the
-  // floating point stack still leaving one copy on the frame.
-  Result number = frame_->Pop();
-  number.ToRegister();
-  frame_->Spill(number.reg());
-  FloatingPointHelper::LoadFloatOperand(masm_, number.reg());
-  number.Unuse();
-
-  // Perform the operation on the number.
-  switch (op) {
-    case SIN:
-      __ fsin();
-      break;
-    case COS:
-      __ fcos();
-      break;
-  }
-
-  // Go slow case if argument to operation is out of range.
-  Result eax_reg = allocator_->Allocate(eax);
-  ASSERT(eax_reg.is_valid());
-  __ fnstsw_ax();
-  __ sahf();
-  eax_reg.Unuse();
-  call_runtime.Branch(parity_even, not_taken);
-
-  // Allocate heap number for result if possible.
-  Result scratch1 = allocator()->Allocate();
-  Result scratch2 = allocator()->Allocate();
-  Result heap_number = allocator()->Allocate();
-  __ AllocateHeapNumber(heap_number.reg(),
-                        scratch1.reg(),
-                        scratch2.reg(),
-                        call_runtime.entry_label());
-  scratch1.Unuse();
-  scratch2.Unuse();
-
-  // Store the result in the allocated heap number.
-  __ fstp_d(FieldOperand(heap_number.reg(), HeapNumber::kValueOffset));
-  // Replace the extra copy of the argument with the result.
-  frame_->SetElementAt(0, &heap_number);
-  done.Jump();
-
-  call_runtime.Bind();
-  // Free ST(0) which was not popped before calling into the runtime.
-  __ ffree(0);
-  Result answer;
-  switch (op) {
-    case SIN:
-      answer = frame_->CallRuntime(Runtime::kMath_sin, 1);
-      break;
-    case COS:
-      answer = frame_->CallRuntime(Runtime::kMath_cos, 1);
-      break;
-  }
-  frame_->Push(&answer);
-  done.Bind();
-}
-
-
 void CodeGenerator::GenerateStringAdd(ZoneList<Expression*>* args) {
   ASSERT_EQ(2, args->length());
 
@@ -5423,6 +5428,45 @@
 }
 
 
+void CodeGenerator::GenerateSubString(ZoneList<Expression*>* args) {
+  ASSERT_EQ(3, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+  Load(args->at(2));
+
+  SubStringStub stub;
+  Result answer = frame_->CallStub(&stub, 3);
+  frame_->Push(&answer);
+}
+
+
+void CodeGenerator::GenerateStringCompare(ZoneList<Expression*>* args) {
+  ASSERT_EQ(2, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+
+  StringCompareStub stub;
+  Result answer = frame_->CallStub(&stub, 2);
+  frame_->Push(&answer);
+}
+
+
+void CodeGenerator::GenerateRegExpExec(ZoneList<Expression*>* args) {
+  ASSERT_EQ(args->length(), 4);
+
+  // Load the arguments on the stack and call the stub.
+  Load(args->at(0));
+  Load(args->at(1));
+  Load(args->at(2));
+  Load(args->at(3));
+  RegExpExecStub stub;
+  Result result = frame_->CallStub(&stub, 4);
+  frame_->Push(&result);
+}
+
+
 void CodeGenerator::VisitCallRuntime(CallRuntime* node) {
   if (CheckForInlineRuntimeCall(node)) {
     return;
@@ -5551,12 +5595,12 @@
 
   } else {
     Load(node->expression());
+    bool overwrite =
+        (node->expression()->AsBinaryOperation() != NULL &&
+         node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
     switch (op) {
       case Token::SUB: {
-        bool overwrite =
-          (node->expression()->AsBinaryOperation() != NULL &&
-           node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
-        UnarySubStub stub(overwrite);
+        GenericUnaryOpStub stub(Token::SUB, overwrite);
         // TODO(1222589): remove dependency of TOS being cached inside stub
         Result operand = frame_->Pop();
         Result answer = frame_->CallStub(&stub, &operand);
@@ -5573,16 +5617,16 @@
         __ test(operand.reg(), Immediate(kSmiTagMask));
         smi_label.Branch(zero, &operand, taken);
 
-        frame_->Push(&operand);  // undo popping of TOS
-        Result answer = frame_->InvokeBuiltin(Builtins::BIT_NOT,
-                                              CALL_FUNCTION, 1);
-
+        GenericUnaryOpStub stub(Token::BIT_NOT, overwrite);
+        Result answer = frame_->CallStub(&stub, &operand);
         continue_label.Jump(&answer);
+
         smi_label.Bind(&answer);
         answer.ToRegister();
         frame_->Spill(answer.reg());
         __ not_(answer.reg());
         __ and_(answer.reg(), ~kSmiTagMask);  // Remove inverted smi-tag.
+
         continue_label.Bind(&answer);
         frame_->Push(&answer);
         break;
@@ -5964,6 +6008,8 @@
 void CodeGenerator::VisitCompareOperation(CompareOperation* node) {
   Comment cmnt(masm_, "[ CompareOperation");
 
+  bool left_already_loaded = false;
+
   // Get the expressions from the node.
   Expression* left = node->left();
   Expression* right = node->right();
@@ -6044,7 +6090,6 @@
       __ CmpInstanceType(answer.reg(), JS_REGEXP_TYPE);
       answer.Unuse();
       destination()->Split(equal);
-
     } else if (check->Equals(Heap::object_symbol())) {
       __ test(answer.reg(), Immediate(kSmiTagMask));
       destination()->false_target()->Branch(zero);
@@ -6076,6 +6121,38 @@
       destination()->Goto(false);
     }
     return;
+  } else if (op == Token::LT &&
+             right->AsLiteral() != NULL &&
+             right->AsLiteral()->handle()->IsHeapNumber()) {
+    Handle<HeapNumber> check(HeapNumber::cast(*right->AsLiteral()->handle()));
+    if (check->value() == 2147483648.0) {  // 0x80000000.
+      Load(left);
+      left_already_loaded = true;
+      Result lhs = frame_->Pop();
+      lhs.ToRegister();
+      __ test(lhs.reg(), Immediate(kSmiTagMask));
+      destination()->true_target()->Branch(zero);  // All Smis are less.
+      Result scratch = allocator()->Allocate();
+      ASSERT(scratch.is_valid());
+      __ mov(scratch.reg(), FieldOperand(lhs.reg(), HeapObject::kMapOffset));
+      __ cmp(scratch.reg(), Factory::heap_number_map());
+      JumpTarget not_a_number;
+      not_a_number.Branch(not_equal, &lhs);
+      __ mov(scratch.reg(),
+             FieldOperand(lhs.reg(), HeapNumber::kExponentOffset));
+      __ cmp(Operand(scratch.reg()), Immediate(0xfff00000));
+      not_a_number.Branch(above_equal, &lhs);  // It's a negative NaN or -Inf.
+      const uint32_t borderline_exponent =
+          (HeapNumber::kExponentBias + 31) << HeapNumber::kExponentShift;
+      __ cmp(Operand(scratch.reg()), Immediate(borderline_exponent));
+      scratch.Unuse();
+      lhs.Unuse();
+      destination()->true_target()->Branch(less);
+      destination()->false_target()->Jump();
+
+      not_a_number.Bind(&lhs);
+      frame_->Push(&lhs);
+    }
   }
 
   Condition cc = no_condition;
@@ -6100,14 +6177,14 @@
       cc = greater_equal;
       break;
     case Token::IN: {
-      Load(left);
+      if (!left_already_loaded) Load(left);
       Load(right);
       Result answer = frame_->InvokeBuiltin(Builtins::IN, CALL_FUNCTION, 2);
       frame_->Push(&answer);  // push the result
       return;
     }
     case Token::INSTANCEOF: {
-      Load(left);
+      if (!left_already_loaded) Load(left);
       Load(right);
       InstanceofStub stub;
       Result answer = frame_->CallStub(&stub, 2);
@@ -6120,7 +6197,7 @@
     default:
       UNREACHABLE();
   }
-  Load(left);
+  if (!left_already_loaded) Load(left);
   Load(right);
   Comparison(node, cc, strict, destination());
 }
@@ -6462,7 +6539,7 @@
         // Shift the key to get the actual index value and check that
         // it is within bounds.
         __ mov(index.reg(), key.reg());
-        __ sar(index.reg(), kSmiTagSize);
+        __ SmiUntag(index.reg());
         __ cmp(index.reg(),
                FieldOperand(elements.reg(), FixedArray::kLengthOffset));
         deferred->Branch(above_equal);
@@ -6768,13 +6845,19 @@
   int elements_size = (length_ > 0) ? FixedArray::SizeFor(length_) : 0;
   int size = JSArray::kSize + elements_size;
 
-  // Allocate both the JS array and the elements array in one big
-  // allocation. This avoid multiple limit checks.
-  Label gc;
-  __ AllocateInNewSpace(size, eax, ebx, ecx, &gc, TAG_OBJECT);
+  // Load boilerplate object into ecx and check if we need to create a
+  // boilerplate.
+  Label slow_case;
+  __ mov(ecx, Operand(esp, 3 * kPointerSize));
+  __ mov(eax, Operand(esp, 2 * kPointerSize));
+  ASSERT((kPointerSize == 4) && (kSmiTagSize == 1) && (kSmiTag == 0));
+  __ mov(ecx, FieldOperand(ecx, eax, times_2, FixedArray::kHeaderSize));
+  __ cmp(ecx, Factory::undefined_value());
+  __ j(equal, &slow_case);
 
-  // Get the boilerplate from the stack.
-  __ mov(ecx, Operand(esp, 1 * kPointerSize));
+  // Allocate both the JS array and the elements array in one big
+  // allocation. This avoids multiple limit checks.
+  __ AllocateInNewSpace(size, eax, ebx, edx, &slow_case, TAG_OBJECT);
 
   // Copy the JS array part.
   for (int i = 0; i < JSArray::kSize; i += kPointerSize) {
@@ -6798,12 +6881,12 @@
     }
   }
 
-  // Return and remove the on-stack parameter.
-  __ ret(1 * kPointerSize);
+  // Return and remove the on-stack parameters.
+  __ ret(3 * kPointerSize);
 
-  __ bind(&gc);
-  ExternalReference runtime(Runtime::kCloneShallowLiteralBoilerplate);
-  __ TailCallRuntime(runtime, 1, 1);
+  __ bind(&slow_case);
+  ExternalReference runtime(Runtime::kCreateArrayLiteralShallow);
+  __ TailCallRuntime(runtime, 3, 1);
 }
 
 
@@ -7027,7 +7110,7 @@
       // If the smi tag is 0 we can just leave the tag on one operand.
       ASSERT(kSmiTag == 0);  // adjust code below if not the case
       // Remove tag from one of the operands (but keep sign).
-      __ sar(eax, kSmiTagSize);
+      __ SmiUntag(eax);
       // Do multiplication.
       __ imul(eax, Operand(ebx));  // multiplication of smis; result in eax
       // Go slow on overflows.
@@ -7051,8 +7134,7 @@
       __ test(edx, Operand(edx));
       __ j(not_zero, slow);
       // Tag the result and store it in register eax.
-      ASSERT(kSmiTagSize == times_2);  // adjust code if not the case
-      __ lea(eax, Operand(eax, eax, times_1, kSmiTag));
+      __ SmiTag(eax);
       break;
 
     case Token::MOD:
@@ -7082,8 +7164,8 @@
       // Move the second operand into register ecx.
       __ mov(ecx, Operand(ebx));
       // Remove tags from operands (but keep sign).
-      __ sar(eax, kSmiTagSize);
-      __ sar(ecx, kSmiTagSize);
+      __ SmiUntag(eax);
+      __ SmiUntag(ecx);
       // Perform the operation.
       switch (op_) {
         case Token::SAR:
@@ -7111,8 +7193,7 @@
           UNREACHABLE();
       }
       // Tag the result and store it in register eax.
-      ASSERT(kSmiTagSize == times_2);  // adjust code if not the case
-      __ lea(eax, Operand(eax, eax, times_1, kSmiTag));
+      __ SmiTag(eax);
       break;
 
     default:
@@ -7237,42 +7318,12 @@
     case Token::SAR:
     case Token::SHL:
     case Token::SHR: {
-      FloatingPointHelper::CheckFloatOperands(masm, &call_runtime, ebx);
-      FloatingPointHelper::LoadFloatOperands(masm, ecx);
-
-      Label skip_allocation, non_smi_result, operand_conversion_failure;
-
-      // Reserve space for converted numbers.
-      __ sub(Operand(esp), Immediate(2 * kPointerSize));
-
-      if (use_sse3_) {
-        // Truncate the operands to 32-bit integers and check for
-        // exceptions in doing so.
-        CpuFeatures::Scope scope(SSE3);
-        __ fisttp_s(Operand(esp, 0 * kPointerSize));
-        __ fisttp_s(Operand(esp, 1 * kPointerSize));
-        __ fnstsw_ax();
-        __ test(eax, Immediate(1));
-        __ j(not_zero, &operand_conversion_failure);
-      } else {
-        // Check if right operand is int32.
-        __ fist_s(Operand(esp, 0 * kPointerSize));
-        __ fild_s(Operand(esp, 0 * kPointerSize));
-        __ FCmp();
-        __ j(not_zero, &operand_conversion_failure);
-        __ j(parity_even, &operand_conversion_failure);
-
-        // Check if left operand is int32.
-        __ fist_s(Operand(esp, 1 * kPointerSize));
-        __ fild_s(Operand(esp, 1 * kPointerSize));
-        __ FCmp();
-        __ j(not_zero, &operand_conversion_failure);
-        __ j(parity_even, &operand_conversion_failure);
-      }
-
-      // Get int32 operands and perform bitop.
-      __ pop(ecx);
-      __ pop(eax);
+      Label non_smi_result, skip_allocation;
+      Label operand_conversion_failure;
+      FloatingPointHelper::LoadAsIntegers(
+        masm,
+        use_sse3_,
+        &operand_conversion_failure);
       switch (op_) {
         case Token::BIT_OR:  __ or_(eax, Operand(ecx)); break;
         case Token::BIT_AND: __ and_(eax, Operand(ecx)); break;
@@ -7292,8 +7343,7 @@
         __ j(negative, &non_smi_result);
       }
       // Tag smi result and return.
-      ASSERT(kSmiTagSize == times_2);  // adjust code if not the case
-      __ lea(eax, Operand(eax, eax, times_1, kSmiTag));
+      __ SmiTag(eax);
       GenerateReturn(masm);
 
       // All ops except SHR return a signed int32 that we load in a HeapNumber.
@@ -7318,28 +7368,20 @@
           default: UNREACHABLE();
         }
         // Store the result in the HeapNumber and return.
-        __ mov(Operand(esp, 1 * kPointerSize), ebx);
-        __ fild_s(Operand(esp, 1 * kPointerSize));
-        __ fstp_d(FieldOperand(eax, HeapNumber::kValueOffset));
+        if (CpuFeatures::IsSupported(SSE2)) {
+          CpuFeatures::Scope use_sse2(SSE2);
+          __ cvtsi2sd(xmm0, Operand(ebx));
+          __ movdbl(FieldOperand(eax, HeapNumber::kValueOffset), xmm0);
+        } else {
+          __ mov(Operand(esp, 1 * kPointerSize), ebx);
+          __ fild_s(Operand(esp, 1 * kPointerSize));
+          __ fstp_d(FieldOperand(eax, HeapNumber::kValueOffset));
+        }
         GenerateReturn(masm);
       }
 
-      // Clear the FPU exception flag and reset the stack before calling
-      // the runtime system.
+      // Go to runtime for non-number inputs.
       __ bind(&operand_conversion_failure);
-      __ add(Operand(esp), Immediate(2 * kPointerSize));
-      if (use_sse3_) {
-        // If we've used the SSE3 instructions for truncating the
-        // floating point values to integers and it failed, we have a
-        // pending #IA exception. Clear it.
-        __ fnclex();
-      } else {
-        // The non-SSE3 variant does early bailout if the right
-        // operand isn't a 32-bit integer, so we may have a single
-        // value on the FPU stack we need to get rid of.
-        __ ffree(0);
-      }
-
       // SHR should return uint32 - go to runtime for non-smi/negative result.
       if (op_ == Token::SHR) {
         __ bind(&non_smi_result);
@@ -7463,6 +7505,197 @@
 }
 
 
+// Get the integer part of a heap number.  Surprisingly, all this bit twiddling
+// is faster than using the built-in instructions on floating point registers.
+// Trashes edi and ebx.  Dest is ecx.  Source cannot be ecx or one of the
+// trashed registers.
+void IntegerConvert(MacroAssembler* masm,
+                    Register source,
+                    bool use_sse3,
+                    Label* conversion_failure) {
+  Label done, right_exponent, normal_exponent;
+  Register scratch = ebx;
+  Register scratch2 = edi;
+  // Get exponent word.
+  __ mov(scratch, FieldOperand(source, HeapNumber::kExponentOffset));
+  // Get exponent alone in scratch2.
+  __ mov(scratch2, scratch);
+  __ and_(scratch2, HeapNumber::kExponentMask);
+  if (use_sse3) {
+    CpuFeatures::Scope scope(SSE3);
+    // Check whether the exponent is too big for a 64 bit signed integer.
+    static const uint32_t kTooBigExponent =
+        (HeapNumber::kExponentBias + 63) << HeapNumber::kExponentShift;
+    __ cmp(Operand(scratch2), Immediate(kTooBigExponent));
+    __ j(greater_equal, conversion_failure);
+    // Load x87 register with heap number.
+    __ fld_d(FieldOperand(source, HeapNumber::kValueOffset));
+    // Reserve space for 64 bit answer.
+    __ sub(Operand(esp), Immediate(sizeof(uint64_t)));  // Nolint.
+    // Do conversion, which cannot fail because we checked the exponent.
+    __ fisttp_d(Operand(esp, 0));
+    __ mov(ecx, Operand(esp, 0));  // Load low word of answer into ecx.
+    __ add(Operand(esp), Immediate(sizeof(uint64_t)));  // Nolint.
+  } else {
+    // Load ecx with zero.  We use this either for the final shift or
+    // for the answer.
+    __ xor_(ecx, Operand(ecx));
+    // Check whether the exponent matches a 32 bit signed int that cannot be
+    // represented by a Smi.  A non-smi 32 bit integer is 1.xxx * 2^30 so the
+    // exponent is 30 (biased).  This is the exponent that we are fastest at and
+    // also the highest exponent we can handle here.
+    const uint32_t non_smi_exponent =
+        (HeapNumber::kExponentBias + 30) << HeapNumber::kExponentShift;
+    __ cmp(Operand(scratch2), Immediate(non_smi_exponent));
+    // If we have a match of the int32-but-not-Smi exponent then skip some
+    // logic.
+    __ j(equal, &right_exponent);
+    // If the exponent is higher than that then go to slow case.  This catches
+    // numbers that don't fit in a signed int32, infinities and NaNs.
+    __ j(less, &normal_exponent);
+
+    {
+      // Handle a big exponent.  The only reason we have this code is that the
+      // >>> operator has a tendency to generate numbers with an exponent of 31.
+      const uint32_t big_non_smi_exponent =
+          (HeapNumber::kExponentBias + 31) << HeapNumber::kExponentShift;
+      __ cmp(Operand(scratch2), Immediate(big_non_smi_exponent));
+      __ j(not_equal, conversion_failure);
+      // We have the big exponent, typically from >>>.  This means the number is
+      // in the range 2^31 to 2^32 - 1.  Get the top bits of the mantissa.
+      __ mov(scratch2, scratch);
+      __ and_(scratch2, HeapNumber::kMantissaMask);
+      // Put back the implicit 1.
+      __ or_(scratch2, 1 << HeapNumber::kExponentShift);
+      // Shift up the mantissa bits to take up the space the exponent used to
+      // take. We just orred in the implicit bit so that took care of one and
+      // we want to use the full unsigned range so we subtract 1 bit from the
+      // shift distance.
+      const int big_shift_distance = HeapNumber::kNonMantissaBitsInTopWord - 1;
+      __ shl(scratch2, big_shift_distance);
+      // Get the second half of the double.
+      __ mov(ecx, FieldOperand(source, HeapNumber::kMantissaOffset));
+      // Shift down 21 bits to get the most significant 11 bits or the low
+      // mantissa word.
+      __ shr(ecx, 32 - big_shift_distance);
+      __ or_(ecx, Operand(scratch2));
+      // We have the answer in ecx, but we may need to negate it.
+      __ test(scratch, Operand(scratch));
+      __ j(positive, &done);
+      __ neg(ecx);
+      __ jmp(&done);
+    }
+
+    __ bind(&normal_exponent);
+    // Exponent word in scratch, exponent part of exponent word in scratch2.
+    // Zero in ecx.
+    // We know the exponent is smaller than 30 (biased).  If it is less than
+    // 0 (biased) then the number is smaller in magnitude than 1.0 * 2^0, ie
+    // it rounds to zero.
+    const uint32_t zero_exponent =
+        (HeapNumber::kExponentBias + 0) << HeapNumber::kExponentShift;
+    __ sub(Operand(scratch2), Immediate(zero_exponent));
+    // ecx already has a Smi zero.
+    __ j(less, &done);
+
+    // We have a shifted exponent between 0 and 30 in scratch2.
+    __ shr(scratch2, HeapNumber::kExponentShift);
+    __ mov(ecx, Immediate(30));
+    __ sub(ecx, Operand(scratch2));
+
+    __ bind(&right_exponent);
+    // Here ecx is the shift, scratch is the exponent word.
+    // Get the top bits of the mantissa.
+    __ and_(scratch, HeapNumber::kMantissaMask);
+    // Put back the implicit 1.
+    __ or_(scratch, 1 << HeapNumber::kExponentShift);
+    // Shift up the mantissa bits to take up the space the exponent used to
+    // take. We have kExponentShift + 1 significant bits int he low end of the
+    // word.  Shift them to the top bits.
+    const int shift_distance = HeapNumber::kNonMantissaBitsInTopWord - 2;
+    __ shl(scratch, shift_distance);
+    // Get the second half of the double. For some exponents we don't
+    // actually need this because the bits get shifted out again, but
+    // it's probably slower to test than just to do it.
+    __ mov(scratch2, FieldOperand(source, HeapNumber::kMantissaOffset));
+    // Shift down 22 bits to get the most significant 10 bits or the low
+    // mantissa word.
+    __ shr(scratch2, 32 - shift_distance);
+    __ or_(scratch2, Operand(scratch));
+    // Move down according to the exponent.
+    __ shr_cl(scratch2);
+    // Now the unsigned answer is in scratch2.  We need to move it to ecx and
+    // we may need to fix the sign.
+    Label negative;
+    __ xor_(ecx, Operand(ecx));
+    __ cmp(ecx, FieldOperand(source, HeapNumber::kExponentOffset));
+    __ j(greater, &negative);
+    __ mov(ecx, scratch2);
+    __ jmp(&done);
+    __ bind(&negative);
+    __ sub(ecx, Operand(scratch2));
+    __ bind(&done);
+  }
+}
+
+
+// Input: edx, eax are the left and right objects of a bit op.
+// Output: eax, ecx are left and right integers for a bit op.
+void FloatingPointHelper::LoadAsIntegers(MacroAssembler* masm,
+                                         bool use_sse3,
+                                         Label* conversion_failure) {
+  // Check float operands.
+  Label arg1_is_object, check_undefined_arg1;
+  Label arg2_is_object, check_undefined_arg2;
+  Label load_arg2, done;
+
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(not_zero, &arg1_is_object);
+  __ SmiUntag(edx);
+  __ jmp(&load_arg2);
+
+  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
+  __ bind(&check_undefined_arg1);
+  __ cmp(edx, Factory::undefined_value());
+  __ j(not_equal, conversion_failure);
+  __ mov(edx, Immediate(0));
+  __ jmp(&load_arg2);
+
+  __ bind(&arg1_is_object);
+  __ mov(ebx, FieldOperand(edx, HeapObject::kMapOffset));
+  __ cmp(ebx, Factory::heap_number_map());
+  __ j(not_equal, &check_undefined_arg1);
+  // Get the untagged integer version of the edx heap number in ecx.
+  IntegerConvert(masm, edx, use_sse3, conversion_failure);
+  __ mov(edx, ecx);
+
+  // Here edx has the untagged integer, eax has a Smi or a heap number.
+  __ bind(&load_arg2);
+  // Test if arg2 is a Smi.
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(not_zero, &arg2_is_object);
+  __ SmiUntag(eax);
+  __ mov(ecx, eax);
+  __ jmp(&done);
+
+  // If the argument is undefined it converts to zero (ECMA-262, section 9.5).
+  __ bind(&check_undefined_arg2);
+  __ cmp(eax, Factory::undefined_value());
+  __ j(not_equal, conversion_failure);
+  __ mov(ecx, Immediate(0));
+  __ jmp(&done);
+
+  __ bind(&arg2_is_object);
+  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
+  __ cmp(ebx, Factory::heap_number_map());
+  __ j(not_equal, &check_undefined_arg2);
+  // Get the untagged integer version of the eax heap number in ecx.
+  IntegerConvert(masm, eax, use_sse3, conversion_failure);
+  __ bind(&done);
+  __ mov(eax, edx);
+}
+
+
 void FloatingPointHelper::LoadFloatOperand(MacroAssembler* masm,
                                            Register number) {
   Label load_smi, done;
@@ -7473,7 +7706,7 @@
   __ jmp(&done);
 
   __ bind(&load_smi);
-  __ sar(number, kSmiTagSize);
+  __ SmiUntag(number);
   __ push(number);
   __ fild_s(Operand(esp, 0));
   __ pop(number);
@@ -7499,14 +7732,14 @@
   __ j(equal, &load_float_eax);
   __ jmp(not_numbers);  // Argument in eax is not a number.
   __ bind(&load_smi_edx);
-  __ sar(edx, 1);  // Untag smi before converting to float.
+  __ SmiUntag(edx);  // Untag smi before converting to float.
   __ cvtsi2sd(xmm0, Operand(edx));
-  __ shl(edx, 1);  // Retag smi for heap number overwriting test.
+  __ SmiTag(edx);  // Retag smi for heap number overwriting test.
   __ jmp(&load_eax);
   __ bind(&load_smi_eax);
-  __ sar(eax, 1);  // Untag smi before converting to float.
+  __ SmiUntag(eax);  // Untag smi before converting to float.
   __ cvtsi2sd(xmm1, Operand(eax));
-  __ shl(eax, 1);  // Retag smi for heap number overwriting test.
+  __ SmiTag(eax);  // Retag smi for heap number overwriting test.
   __ jmp(&done);
   __ bind(&load_float_eax);
   __ movdbl(xmm1, FieldOperand(eax, HeapNumber::kValueOffset));
@@ -7530,14 +7763,14 @@
   __ jmp(&done);
 
   __ bind(&load_smi_1);
-  __ sar(scratch, kSmiTagSize);
+  __ SmiUntag(scratch);
   __ push(scratch);
   __ fild_s(Operand(esp, 0));
   __ pop(scratch);
   __ jmp(&done_load_1);
 
   __ bind(&load_smi_2);
-  __ sar(scratch, kSmiTagSize);
+  __ SmiUntag(scratch);
   __ push(scratch);
   __ fild_s(Operand(esp, 0));
   __ pop(scratch);
@@ -7570,86 +7803,142 @@
 }
 
 
-void UnarySubStub::Generate(MacroAssembler* masm) {
-  Label undo;
-  Label slow;
-  Label done;
-  Label try_float;
+void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
+  Label slow, done;
 
-  // Check whether the value is a smi.
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(not_zero, &try_float, not_taken);
+  if (op_ == Token::SUB) {
+    // Check whether the value is a smi.
+    Label try_float;
+    __ test(eax, Immediate(kSmiTagMask));
+    __ j(not_zero, &try_float, not_taken);
 
-  // Enter runtime system if the value of the expression is zero
-  // to make sure that we switch between 0 and -0.
-  __ test(eax, Operand(eax));
-  __ j(zero, &slow, not_taken);
+    // Go slow case if the value of the expression is zero
+    // to make sure that we switch between 0 and -0.
+    __ test(eax, Operand(eax));
+    __ j(zero, &slow, not_taken);
 
-  // The value of the expression is a smi that is not zero.  Try
-  // optimistic subtraction '0 - value'.
-  __ mov(edx, Operand(eax));
-  __ Set(eax, Immediate(0));
-  __ sub(eax, Operand(edx));
-  __ j(overflow, &undo, not_taken);
-
-  // If result is a smi we are done.
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &done, taken);
-
-  // Restore eax and enter runtime system.
-  __ bind(&undo);
-  __ mov(eax, Operand(edx));
-
-  // Enter runtime system.
-  __ bind(&slow);
-  __ pop(ecx);  // pop return address
-  __ push(eax);
-  __ push(ecx);  // push return address
-  __ InvokeBuiltin(Builtins::UNARY_MINUS, JUMP_FUNCTION);
-
-  // Try floating point case.
-  __ bind(&try_float);
-  __ mov(edx, FieldOperand(eax, HeapObject::kMapOffset));
-  __ cmp(edx, Factory::heap_number_map());
-  __ j(not_equal, &slow);
-  if (overwrite_) {
-    __ mov(edx, FieldOperand(eax, HeapNumber::kExponentOffset));
-    __ xor_(edx, HeapNumber::kSignMask);  // Flip sign.
-    __ mov(FieldOperand(eax, HeapNumber::kExponentOffset), edx);
-  } else {
+    // The value of the expression is a smi that is not zero.  Try
+    // optimistic subtraction '0 - value'.
+    Label undo;
     __ mov(edx, Operand(eax));
-    // edx: operand
-    __ AllocateHeapNumber(eax, ebx, ecx, &undo);
-    // eax: allocated 'empty' number
-    __ mov(ecx, FieldOperand(edx, HeapNumber::kExponentOffset));
-    __ xor_(ecx, HeapNumber::kSignMask);  // Flip sign.
-    __ mov(FieldOperand(eax, HeapNumber::kExponentOffset), ecx);
-    __ mov(ecx, FieldOperand(edx, HeapNumber::kMantissaOffset));
-    __ mov(FieldOperand(eax, HeapNumber::kMantissaOffset), ecx);
+    __ Set(eax, Immediate(0));
+    __ sub(eax, Operand(edx));
+    __ j(overflow, &undo, not_taken);
+
+    // If result is a smi we are done.
+    __ test(eax, Immediate(kSmiTagMask));
+    __ j(zero, &done, taken);
+
+    // Restore eax and go slow case.
+    __ bind(&undo);
+    __ mov(eax, Operand(edx));
+    __ jmp(&slow);
+
+    // Try floating point case.
+    __ bind(&try_float);
+    __ mov(edx, FieldOperand(eax, HeapObject::kMapOffset));
+    __ cmp(edx, Factory::heap_number_map());
+    __ j(not_equal, &slow);
+    if (overwrite_) {
+      __ mov(edx, FieldOperand(eax, HeapNumber::kExponentOffset));
+      __ xor_(edx, HeapNumber::kSignMask);  // Flip sign.
+      __ mov(FieldOperand(eax, HeapNumber::kExponentOffset), edx);
+    } else {
+      __ mov(edx, Operand(eax));
+      // edx: operand
+      __ AllocateHeapNumber(eax, ebx, ecx, &undo);
+      // eax: allocated 'empty' number
+      __ mov(ecx, FieldOperand(edx, HeapNumber::kExponentOffset));
+      __ xor_(ecx, HeapNumber::kSignMask);  // Flip sign.
+      __ mov(FieldOperand(eax, HeapNumber::kExponentOffset), ecx);
+      __ mov(ecx, FieldOperand(edx, HeapNumber::kMantissaOffset));
+      __ mov(FieldOperand(eax, HeapNumber::kMantissaOffset), ecx);
+    }
+  } else if (op_ == Token::BIT_NOT) {
+    // Check if the operand is a heap number.
+    __ mov(edx, FieldOperand(eax, HeapObject::kMapOffset));
+    __ cmp(edx, Factory::heap_number_map());
+    __ j(not_equal, &slow, not_taken);
+
+    // Convert the heap number in eax to an untagged integer in ecx.
+    IntegerConvert(masm, eax, CpuFeatures::IsSupported(SSE3), &slow);
+
+    // Do the bitwise operation and check if the result fits in a smi.
+    Label try_float;
+    __ not_(ecx);
+    __ cmp(ecx, 0xc0000000);
+    __ j(sign, &try_float, not_taken);
+
+    // Tag the result as a smi and we're done.
+    ASSERT(kSmiTagSize == 1);
+    __ lea(eax, Operand(ecx, times_2, kSmiTag));
+    __ jmp(&done);
+
+    // Try to store the result in a heap number.
+    __ bind(&try_float);
+    if (!overwrite_) {
+      // Allocate a fresh heap number, but don't overwrite eax until
+      // we're sure we can do it without going through the slow case
+      // that needs the value in eax.
+      __ AllocateHeapNumber(ebx, edx, edi, &slow);
+      __ mov(eax, Operand(ebx));
+    }
+    if (CpuFeatures::IsSupported(SSE2)) {
+      CpuFeatures::Scope use_sse2(SSE2);
+      __ cvtsi2sd(xmm0, Operand(ecx));
+      __ movdbl(FieldOperand(eax, HeapNumber::kValueOffset), xmm0);
+    } else {
+      __ push(ecx);
+      __ fild_s(Operand(esp, 0));
+      __ pop(ecx);
+      __ fstp_d(FieldOperand(eax, HeapNumber::kValueOffset));
+    }
+  } else {
+    UNIMPLEMENTED();
   }
 
+  // Return from the stub.
   __ bind(&done);
-
   __ StubReturn(1);
+
+  // Handle the slow case by jumping to the JavaScript builtin.
+  __ bind(&slow);
+  __ pop(ecx);  // pop return address.
+  __ push(eax);
+  __ push(ecx);  // push return address
+  switch (op_) {
+    case Token::SUB:
+      __ InvokeBuiltin(Builtins::UNARY_MINUS, JUMP_FUNCTION);
+      break;
+    case Token::BIT_NOT:
+      __ InvokeBuiltin(Builtins::BIT_NOT, JUMP_FUNCTION);
+      break;
+    default:
+      UNREACHABLE();
+  }
 }
 
 
 void ArgumentsAccessStub::GenerateReadLength(MacroAssembler* masm) {
   // Check if the calling frame is an arguments adaptor frame.
-  Label adaptor;
   __ mov(edx, Operand(ebp, StandardFrameConstants::kCallerFPOffset));
   __ mov(ecx, Operand(edx, StandardFrameConstants::kContextOffset));
   __ cmp(Operand(ecx), Immediate(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
-  __ j(equal, &adaptor);
-
-  // Nothing to do: The formal number of parameters has already been
-  // passed in register eax by calling function. Just return it.
-  __ ret(0);
 
   // Arguments adaptor case: Read the arguments length from the
   // adaptor frame and return it.
-  __ bind(&adaptor);
-  __ mov(eax, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  // Otherwise nothing to do: The number of formal parameters has already been
+  // passed in register eax by calling function. Just return it.
+  if (CpuFeatures::IsSupported(CMOV)) {
+    CpuFeatures::Scope use_cmov(CMOV);
+    __ cmov(equal, eax,
+            Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  } else {
+    Label exit;
+    __ j(not_equal, &exit);
+    __ mov(eax, Operand(edx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+    __ bind(&exit);
+  }
   __ ret(0);
 }
 
@@ -7778,7 +8067,7 @@
 
   // Get the parameters pointer from the stack and untag the length.
   __ mov(edx, Operand(esp, 2 * kPointerSize));
-  __ sar(ecx, kSmiTagSize);
+  __ SmiUntag(ecx);
 
   // Setup the elements pointer in the allocated arguments object and
   // initialize the header in the elements fixed array.
@@ -7809,6 +8098,278 @@
 }
 
 
+void RegExpExecStub::Generate(MacroAssembler* masm) {
+  // Just jump directly to runtime if regexp entry in generated code is turned
+  // off.
+  if (!FLAG_regexp_entry_native) {
+    __ TailCallRuntime(ExternalReference(Runtime::kRegExpExec), 4, 1);
+    return;
+  }
+
+  // Stack frame on entry.
+  //  esp[0]: return address
+  //  esp[4]: last_match_info (expected JSArray)
+  //  esp[8]: previous index
+  //  esp[12]: subject string
+  //  esp[16]: JSRegExp object
+
+  Label runtime;
+
+  // Check that the first argument is a JSRegExp object.
+  __ mov(eax, Operand(esp, 4 * kPointerSize));
+  ASSERT_EQ(0, kSmiTag);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+  __ CmpObjectType(eax, JS_REGEXP_TYPE, ecx);
+  __ j(not_equal, &runtime);
+  // Check that the RegExp has been compiled (data contains a fixed array).
+  __ mov(ecx, FieldOperand(eax, JSRegExp::kDataOffset));
+#ifdef DEBUG
+  __ test(ecx, Immediate(kSmiTagMask));
+  __ Check(not_zero, "Unexpected type for RegExp data, FixedArray expected");
+  __ CmpObjectType(ecx, FIXED_ARRAY_TYPE, ebx);
+  __ Check(equal, "Unexpected type for RegExp data, FixedArray expected");
+#endif
+
+  // ecx: RegExp data (FixedArray)
+  // Check the type of the RegExp. Only continue if type is JSRegExp::IRREGEXP.
+  __ mov(ebx, FieldOperand(ecx, JSRegExp::kDataTagOffset));
+  __ cmp(Operand(ebx), Immediate(Smi::FromInt(JSRegExp::IRREGEXP)));
+  __ j(not_equal, &runtime);
+
+  // ecx: RegExp data (FixedArray)
+  // Check that the number of captures fit in the static offsets vector buffer.
+  __ mov(edx, FieldOperand(ecx, JSRegExp::kIrregexpCaptureCountOffset));
+  // Calculate number of capture registers (number_of_captures + 1) * 2. This
+  // uses the asumption that smis are 2 * their untagged value.
+  ASSERT_EQ(0, kSmiTag);
+  ASSERT_EQ(1, kSmiTagSize + kSmiShiftSize);
+  __ add(Operand(edx), Immediate(2));  // edx was a smi.
+  // Check that the static offsets vector buffer is large enough.
+  __ cmp(edx, OffsetsVector::kStaticOffsetsVectorSize);
+  __ j(above, &runtime);
+
+  // ecx: RegExp data (FixedArray)
+  // edx: Number of capture registers
+  // Check that the second argument is a string.
+  __ mov(eax, Operand(esp, 3 * kPointerSize));
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+  Condition is_string = masm->IsObjectStringType(eax, ebx, ebx);
+  __ j(NegateCondition(is_string), &runtime);
+  // Get the length of the string to ebx.
+  __ mov(ebx, FieldOperand(eax, String::kLengthOffset));
+
+  // ebx: Length of subject string
+  // ecx: RegExp data (FixedArray)
+  // edx: Number of capture registers
+  // Check that the third argument is a positive smi.
+  __ mov(eax, Operand(esp, 2 * kPointerSize));
+  __ test(eax, Immediate(kSmiTagMask | 0x80000000));
+  __ j(not_zero, &runtime);
+  // Check that it is not greater than the subject string length.
+  __ SmiUntag(eax);
+  __ cmp(eax, Operand(ebx));
+  __ j(greater, &runtime);
+
+  // ecx: RegExp data (FixedArray)
+  // edx: Number of capture registers
+  // Check that the fourth object is a JSArray object.
+  __ mov(eax, Operand(esp, 1 * kPointerSize));
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+  __ CmpObjectType(eax, JS_ARRAY_TYPE, ebx);
+  __ j(not_equal, &runtime);
+  // Check that the JSArray is in fast case.
+  __ mov(ebx, FieldOperand(eax, JSArray::kElementsOffset));
+  __ mov(eax, FieldOperand(ebx, HeapObject::kMapOffset));
+  __ cmp(eax, Factory::fixed_array_map());
+  __ j(not_equal, &runtime);
+  // Check that the last match info has space for the capture registers and the
+  // additional information.
+  __ mov(eax, FieldOperand(ebx, FixedArray::kLengthOffset));
+  __ add(Operand(edx), Immediate(RegExpImpl::kLastMatchOverhead));
+  __ cmp(edx, Operand(eax));
+  __ j(greater, &runtime);
+
+  // ecx: RegExp data (FixedArray)
+  // Check the representation and encoding of the subject string (only support
+  // flat ascii strings).
+  __ mov(eax, Operand(esp, 3 * kPointerSize));
+  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
+  __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
+  __ and_(ebx, kStringRepresentationMask | kStringEncodingMask);
+  __ cmp(ebx, kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &runtime);
+
+  // ecx: RegExp data (FixedArray)
+  // Ensure that a RegExp stack is allocated.
+  ExternalReference address_of_regexp_stack_memory_address =
+      ExternalReference::address_of_regexp_stack_memory_address();
+  ExternalReference address_of_regexp_stack_memory_size =
+      ExternalReference::address_of_regexp_stack_memory_size();
+  __ mov(eax, Operand::StaticVariable(address_of_regexp_stack_memory_size));
+  __ test(eax, Operand(eax));
+  __ j(zero, &runtime, not_taken);
+
+  // ecx: RegExp data (FixedArray)
+  // Check that the irregexp code has been generated for an ascii string. If
+  // it has the field contains a code object otherwise it contains the hole.
+  __ mov(edx, FieldOperand(ecx, JSRegExp::kDataAsciiCodeOffset));
+  __ CmpObjectType(edx, CODE_TYPE, ebx);
+  __ j(not_equal, &runtime);
+
+  // Load used arguments before starting to push arguments for call to native
+  // RegExp code to avoid handling changing stack height.
+  __ mov(eax, Operand(esp, 3 * kPointerSize));  // Subject string.
+  __ mov(ebx, Operand(esp, 2 * kPointerSize));  // Previous index.
+  __ mov(ecx, Operand(esp, 4 * kPointerSize));  // JSRegExp object.
+  __ SmiUntag(ebx);  // Previous index from sim.
+
+  // eax: subject string
+  // ebx: previous index
+  // edx: code
+  // All checks done. Now push arguments for native regexp code.
+  __ IncrementCounter(&Counters::regexp_entry_native, 1);
+
+  // Argument 8: Indicate that this is a direct call from JavaScript.
+  __ push(Immediate(1));
+
+  // Argument 7: Start (high end) of backtracking stack memory area.
+  __ mov(ecx, Operand::StaticVariable(address_of_regexp_stack_memory_address));
+  __ add(ecx, Operand::StaticVariable(address_of_regexp_stack_memory_size));
+  __ push(ecx);
+
+  // Argument 6: At start of string?
+  __ xor_(Operand(ecx), ecx);  // setcc only operated on cl (lower byte of ecx).
+  __ test(ebx, Operand(ebx));
+  __ setcc(zero, ecx);  // 1 if 0 (start of string), 0 if positive.
+  __ push(ecx);
+
+  // Argument 5: static offsets vector buffer.
+  __ push(Immediate(ExternalReference::address_of_static_offsets_vector()));
+
+  // Argument 4: End of string data.
+  __ mov(ecx, FieldOperand(eax, String::kLengthOffset));
+  __ add(ecx, Operand(eax));
+  __ add(Operand(ecx), Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ push(ecx);
+
+  // Argument 3: Start of string data.
+  __ mov(ecx, ebx);
+  __ add(ebx, Operand(eax));  // String is ASCII.
+  __ add(Operand(ebx), Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ push(ebx);
+
+  // Argument 2: Previous index.
+  __ push(ecx);
+
+  // Argument 1: Subject string.
+  __ push(eax);
+
+  // Locate the code entry and call it.
+  __ add(Operand(edx), Immediate(Code::kHeaderSize - kHeapObjectTag));
+  __ call(Operand(edx));
+  // Remove arguments.
+  __ add(Operand(esp), Immediate(8 * kPointerSize));
+
+  // Check the result.
+  Label success;
+  __ cmp(eax, NativeRegExpMacroAssembler::SUCCESS);
+  __ j(equal, &success, taken);
+  Label failure;
+  __ cmp(eax, NativeRegExpMacroAssembler::FAILURE);
+  __ j(equal, &failure, taken);
+  __ cmp(eax, NativeRegExpMacroAssembler::EXCEPTION);
+  // If not exception it can only be retry. Handle that in the runtime system.
+  __ j(not_equal, &runtime);
+  // Result must now be exception. If there is no pending exception already a
+  // stack overflow (on the backtrack stack) was detected in RegExp code but
+  // haven't created the exception yet. Handle that in the runtime system.
+  ExternalReference pending_exception(Top::k_pending_exception_address);
+  __ mov(eax,
+         Operand::StaticVariable(ExternalReference::the_hole_value_location()));
+  __ cmp(eax, Operand::StaticVariable(pending_exception));
+  __ j(equal, &runtime);
+  __ bind(&failure);
+  // For failure and exception return null.
+  __ mov(Operand(eax), Factory::null_value());
+  __ ret(4 * kPointerSize);
+
+  // Load RegExp data.
+  __ bind(&success);
+  __ mov(eax, Operand(esp, 4 * kPointerSize));
+  __ mov(ecx, FieldOperand(eax, JSRegExp::kDataOffset));
+  __ mov(edx, FieldOperand(ecx, JSRegExp::kIrregexpCaptureCountOffset));
+  // Calculate number of capture registers (number_of_captures + 1) * 2.
+  __ add(Operand(edx), Immediate(2));  // edx was a smi.
+
+  // edx: Number of capture registers
+  // Load last_match_info which is still known to be a fast case JSArray.
+  __ mov(eax, Operand(esp, 1 * kPointerSize));
+  __ mov(ebx, FieldOperand(eax, JSArray::kElementsOffset));
+
+  // ebx: last_match_info backing store (FixedArray)
+  // edx: number of capture registers
+  // Store the capture count.
+  __ SmiTag(edx);  // Number of capture registers to smi.
+  __ mov(FieldOperand(ebx, RegExpImpl::kLastCaptureCountOffset), edx);
+  __ SmiUntag(edx);  // Number of capture registers back from smi.
+  // Store last subject and last input.
+  __ mov(eax, Operand(esp, 3 * kPointerSize));
+  __ mov(FieldOperand(ebx, RegExpImpl::kLastSubjectOffset), eax);
+  __ mov(ecx, ebx);
+  __ RecordWrite(ecx, RegExpImpl::kLastSubjectOffset, eax, edi);
+  __ mov(eax, Operand(esp, 3 * kPointerSize));
+  __ mov(FieldOperand(ebx, RegExpImpl::kLastInputOffset), eax);
+  __ mov(ecx, ebx);
+  __ RecordWrite(ecx, RegExpImpl::kLastInputOffset, eax, edi);
+
+  // Get the static offsets vector filled by the native regexp code.
+  ExternalReference address_of_static_offsets_vector =
+      ExternalReference::address_of_static_offsets_vector();
+  __ mov(ecx, Immediate(address_of_static_offsets_vector));
+
+  // ebx: last_match_info backing store (FixedArray)
+  // ecx: offsets vector
+  // edx: number of capture registers
+  Label next_capture, done;
+  __ mov(eax, Operand(esp, 2 * kPointerSize));  // Read previous index.
+  // Capture register counter starts from number of capture registers and
+  // counts down until wraping after zero.
+  __ bind(&next_capture);
+  __ sub(Operand(edx), Immediate(1));
+  __ j(negative, &done);
+  // Read the value from the static offsets vector buffer.
+  __ mov(edi, Operand(ecx, edx, times_pointer_size, 0));
+  // Perform explicit shift
+  ASSERT_EQ(0, kSmiTag);
+  __ shl(edi, kSmiTagSize);
+  // Add previous index (from its stack slot) if value is not negative.
+  Label capture_negative;
+  // Carry flag set by shift above.
+  __ j(negative, &capture_negative, not_taken);
+  __ add(edi, Operand(eax));  // Add previous index (adding smi to smi).
+  __ bind(&capture_negative);
+  // Store the smi value in the last match info.
+  __ mov(FieldOperand(ebx,
+                      edx,
+                      times_pointer_size,
+                      RegExpImpl::kFirstCaptureOffset),
+                      edi);
+  __ jmp(&next_capture);
+  __ bind(&done);
+
+  // Return last match info.
+  __ mov(eax, Operand(esp, 1 * kPointerSize));
+  __ ret(4 * kPointerSize);
+
+  // Do the runtime call to execute the regexp.
+  __ bind(&runtime);
+  __ TailCallRuntime(ExternalReference(Runtime::kRegExpExec), 4, 1);
+}
+
+
 void CompareStub::Generate(MacroAssembler* masm) {
   Label call_builtin, done;
 
@@ -7826,35 +8387,41 @@
       // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
       // so we do the second best thing - test it ourselves.
 
-      Label return_equal;
-      Label heap_number;
-      // If it's not a heap number, then return equal.
-      __ cmp(FieldOperand(edx, HeapObject::kMapOffset),
-             Immediate(Factory::heap_number_map()));
-      __ j(equal, &heap_number);
-      __ bind(&return_equal);
-      __ Set(eax, Immediate(0));
-      __ ret(0);
+      if (never_nan_nan_) {
+        __ Set(eax, Immediate(0));
+        __ ret(0);
+      } else {
+        Label return_equal;
+        Label heap_number;
+        // If it's not a heap number, then return equal.
+        __ cmp(FieldOperand(edx, HeapObject::kMapOffset),
+               Immediate(Factory::heap_number_map()));
+        __ j(equal, &heap_number);
+        __ bind(&return_equal);
+        __ Set(eax, Immediate(0));
+        __ ret(0);
 
-      __ bind(&heap_number);
-      // It is a heap number, so return non-equal if it's NaN and equal if it's
-      // not NaN.
-      // The representation of NaN values has all exponent bits (52..62) set,
-      // and not all mantissa bits (0..51) clear.
-      // We only accept QNaNs, which have bit 51 set.
-      // Read top bits of double representation (second word of value).
+        __ bind(&heap_number);
+        // It is a heap number, so return non-equal if it's NaN and equal if
+        // it's not NaN.
+        // The representation of NaN values has all exponent bits (52..62) set,
+        // and not all mantissa bits (0..51) clear.
+        // We only accept QNaNs, which have bit 51 set.
+        // Read top bits of double representation (second word of value).
 
-      // Value is a QNaN if value & kQuietNaNMask == kQuietNaNMask, i.e.,
-      // all bits in the mask are set. We only need to check the word
-      // that contains the exponent and high bit of the mantissa.
-      ASSERT_NE(0, (kQuietNaNHighBitsMask << 1) & 0x80000000u);
-      __ mov(edx, FieldOperand(edx, HeapNumber::kExponentOffset));
-      __ xor_(eax, Operand(eax));
-      // Shift value and mask so kQuietNaNHighBitsMask applies to topmost bits.
-      __ add(edx, Operand(edx));
-      __ cmp(edx, kQuietNaNHighBitsMask << 1);
-      __ setcc(above_equal, eax);
-      __ ret(0);
+        // Value is a QNaN if value & kQuietNaNMask == kQuietNaNMask, i.e.,
+        // all bits in the mask are set. We only need to check the word
+        // that contains the exponent and high bit of the mantissa.
+        ASSERT_NE(0, (kQuietNaNHighBitsMask << 1) & 0x80000000u);
+        __ mov(edx, FieldOperand(edx, HeapNumber::kExponentOffset));
+        __ xor_(eax, Operand(eax));
+        // Shift value and mask so kQuietNaNHighBitsMask applies to topmost
+        // bits.
+        __ add(edx, Operand(edx));
+        __ cmp(edx, kQuietNaNHighBitsMask << 1);
+        __ setcc(above_equal, eax);
+        __ ret(0);
+      }
 
       __ bind(&not_identical);
     }
@@ -8001,9 +8568,10 @@
 
   // Fast negative check for symbol-to-symbol equality.
   __ bind(&check_for_symbols);
+  Label check_for_strings;
   if (cc_ == equal) {
-    BranchIfNonSymbol(masm, &call_builtin, eax, ecx);
-    BranchIfNonSymbol(masm, &call_builtin, edx, ecx);
+    BranchIfNonSymbol(masm, &check_for_strings, eax, ecx);
+    BranchIfNonSymbol(masm, &check_for_strings, edx, ecx);
 
     // We've already checked for object identity, so if both operands
     // are symbols they aren't equal. Register eax already holds a
@@ -8011,6 +8579,44 @@
     __ ret(2 * kPointerSize);
   }
 
+  __ bind(&check_for_strings);
+
+  // Check that both objects are not smis.
+  ASSERT_EQ(0, kSmiTag);
+  __ mov(ebx, Operand(edx));
+  __ and_(ebx, Operand(eax));
+  __ test(ebx, Immediate(kSmiTagMask));
+  __ j(zero, &call_builtin);
+
+  // Load instance type for both objects.
+  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
+  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
+  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
+  __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
+
+  // Check that both are flat ascii strings.
+  Label non_ascii_flat;
+  ASSERT(kNotStringTag != 0);
+  const int kFlatAsciiString =
+      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+  __ and_(ecx, kFlatAsciiString);
+  __ cmp(ecx, kStringTag | kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &call_builtin);
+  __ and_(ebx, kFlatAsciiString);
+  __ cmp(ebx, kStringTag | kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &call_builtin);
+
+  // Inline comparison of ascii strings.
+  StringCompareStub::GenerateCompareFlatAsciiStrings(masm,
+                                                     edx,
+                                                     eax,
+                                                     ecx,
+                                                     ebx,
+                                                     edi);
+#ifdef DEBUG
+  __ Abort("Unexpected fall-through from string comparison");
+#endif
+
   __ bind(&call_builtin);
   // must swap argument order
   __ pop(ecx);
@@ -8579,10 +9185,55 @@
 }
 
 
+// Unfortunately you have to run without snapshots to see most of these
+// names in the profile since most compare stubs end up in the snapshot.
+const char* CompareStub::GetName() {
+  switch (cc_) {
+    case less: return "CompareStub_LT";
+    case greater: return "CompareStub_GT";
+    case less_equal: return "CompareStub_LE";
+    case greater_equal: return "CompareStub_GE";
+    case not_equal: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_NE_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_NO_NAN";
+        } else {
+          return "CompareStub_NE";
+        }
+      }
+    }
+    case equal: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_EQ_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_NO_NAN";
+        } else {
+          return "CompareStub_EQ";
+        }
+      }
+    }
+    default: return "CompareStub";
+  }
+}
+
+
 int CompareStub::MinorKey() {
-  // Encode the two parameters in a unique 16 bit value.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
-  return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
+  // Encode the three parameters in a unique 16 bit value.
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 14));
+  int nnn_value = (never_nan_nan_ ? 2 : 0);
+  if (cc_ != equal) nnn_value = 0;  // Avoid duplicate stubs.
+  return (static_cast<unsigned>(cc_) << 2) | nnn_value | (strict_ ? 1 : 0);
 }
 
 
@@ -8778,12 +9429,12 @@
 }
 
 
-void StringAddStub::GenerateCopyCharacters(MacroAssembler* masm,
-                                           Register dest,
-                                           Register src,
-                                           Register count,
-                                           Register scratch,
-                                           bool ascii) {
+void StringStubBase::GenerateCopyCharacters(MacroAssembler* masm,
+                                            Register dest,
+                                            Register src,
+                                            Register count,
+                                            Register scratch,
+                                            bool ascii) {
   Label loop;
   __ bind(&loop);
   // This loop just copies one character at a time, as it is only used for very
@@ -8804,6 +9455,316 @@
 }
 
 
+void StringStubBase::GenerateCopyCharactersREP(MacroAssembler* masm,
+                                               Register dest,
+                                               Register src,
+                                               Register count,
+                                               Register scratch,
+                                               bool ascii) {
+  // Copy characters using rep movs of doublewords. Align destination on 4 byte
+  // boundary before starting rep movs. Copy remaining characters after running
+  // rep movs.
+  ASSERT(dest.is(edi));  // rep movs destination
+  ASSERT(src.is(esi));  // rep movs source
+  ASSERT(count.is(ecx));  // rep movs count
+  ASSERT(!scratch.is(dest));
+  ASSERT(!scratch.is(src));
+  ASSERT(!scratch.is(count));
+
+  // Nothing to do for zero characters.
+  Label done;
+  __ test(count, Operand(count));
+  __ j(zero, &done);
+
+  // Make count the number of bytes to copy.
+  if (!ascii) {
+    __ shl(count, 1);
+  }
+
+  // Don't enter the rep movs if there are less than 4 bytes to copy.
+  Label last_bytes;
+  __ test(count, Immediate(~3));
+  __ j(zero, &last_bytes);
+
+  // Copy from edi to esi using rep movs instruction.
+  __ mov(scratch, count);
+  __ sar(count, 2);  // Number of doublewords to copy.
+  __ rep_movs();
+
+  // Find number of bytes left.
+  __ mov(count, scratch);
+  __ and_(count, 3);
+
+  // Check if there are more bytes to copy.
+  __ bind(&last_bytes);
+  __ test(count, Operand(count));
+  __ j(zero, &done);
+
+  // Copy remaining characters.
+  Label loop;
+  __ bind(&loop);
+  __ mov_b(scratch, Operand(src, 0));
+  __ mov_b(Operand(dest, 0), scratch);
+  __ add(Operand(src), Immediate(1));
+  __ add(Operand(dest), Immediate(1));
+  __ sub(Operand(count), Immediate(1));
+  __ j(not_zero, &loop);
+
+  __ bind(&done);
+}
+
+
+void SubStringStub::Generate(MacroAssembler* masm) {
+  Label runtime;
+
+  // Stack frame on entry.
+  //  esp[0]: return address
+  //  esp[4]: to
+  //  esp[8]: from
+  //  esp[12]: string
+
+  // Make sure first argument is a string.
+  __ mov(eax, Operand(esp, 3 * kPointerSize));
+  ASSERT_EQ(0, kSmiTag);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+  Condition is_string = masm->IsObjectStringType(eax, ebx, ebx);
+  __ j(NegateCondition(is_string), &runtime);
+
+  // eax: string
+  // ebx: instance type
+  // Calculate length of sub string using the smi values.
+  __ mov(ecx, Operand(esp, 1 * kPointerSize));  // to
+  __ test(ecx, Immediate(kSmiTagMask));
+  __ j(not_zero, &runtime);
+  __ mov(edx, Operand(esp, 2 * kPointerSize));  // from
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(not_zero, &runtime);
+  __ sub(ecx, Operand(edx));
+  // Handle sub-strings of length 2 and less in the runtime system.
+  __ SmiUntag(ecx);  // Result length is no longer smi.
+  __ cmp(ecx, 2);
+  __ j(below_equal, &runtime);
+
+  // eax: string
+  // ebx: instance type
+  // ecx: result string length
+  // Check for flat ascii string
+  Label non_ascii_flat;
+  __ and_(ebx, kStringRepresentationMask | kStringEncodingMask);
+  __ cmp(ebx, kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &non_ascii_flat);
+
+  // Allocate the result.
+  __ AllocateAsciiString(eax, ecx, ebx, edx, edi, &runtime);
+
+  // eax: result string
+  // ecx: result string length
+  __ mov(edx, esi);  // esi used by following code.
+  // Locate first character of result.
+  __ mov(edi, eax);
+  __ add(Operand(edi), Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  // Load string argument and locate character of sub string start.
+  __ mov(esi, Operand(esp, 3 * kPointerSize));
+  __ add(Operand(esi), Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ mov(ebx, Operand(esp, 2 * kPointerSize));  // from
+  __ SmiUntag(ebx);
+  __ add(esi, Operand(ebx));
+
+  // eax: result string
+  // ecx: result length
+  // edx: original value of esi
+  // edi: first character of result
+  // esi: character of sub string start
+  GenerateCopyCharactersREP(masm, edi, esi, ecx, ebx, true);
+  __ mov(esi, edx);  // Restore esi.
+  __ IncrementCounter(&Counters::sub_string_native, 1);
+  __ ret(3 * kPointerSize);
+
+  __ bind(&non_ascii_flat);
+  // eax: string
+  // ebx: instance type & kStringRepresentationMask | kStringEncodingMask
+  // ecx: result string length
+  // Check for flat two byte string
+  __ cmp(ebx, kSeqStringTag | kTwoByteStringTag);
+  __ j(not_equal, &runtime);
+
+  // Allocate the result.
+  __ AllocateTwoByteString(eax, ecx, ebx, edx, edi, &runtime);
+
+  // eax: result string
+  // ecx: result string length
+  __ mov(edx, esi);  // esi used by following code.
+  // Locate first character of result.
+  __ mov(edi, eax);
+  __ add(Operand(edi),
+         Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  // Load string argument and locate character of sub string start.
+  __ mov(esi, Operand(esp, 3 * kPointerSize));
+  __ add(Operand(esi), Immediate(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ mov(ebx, Operand(esp, 2 * kPointerSize));  // from
+  // As from is a smi it is 2 times the value which matches the size of a two
+  // byte character.
+  ASSERT_EQ(0, kSmiTag);
+  ASSERT_EQ(1, kSmiTagSize + kSmiShiftSize);
+  __ add(esi, Operand(ebx));
+
+  // eax: result string
+  // ecx: result length
+  // edx: original value of esi
+  // edi: first character of result
+  // esi: character of sub string start
+  GenerateCopyCharactersREP(masm, edi, esi, ecx, ebx, false);
+  __ mov(esi, edx);  // Restore esi.
+  __ IncrementCounter(&Counters::sub_string_native, 1);
+  __ ret(3 * kPointerSize);
+
+  // Just jump to runtime to create the sub string.
+  __ bind(&runtime);
+  __ TailCallRuntime(ExternalReference(Runtime::kSubString), 3, 1);
+}
+
+
+void StringCompareStub::GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
+                                                        Register left,
+                                                        Register right,
+                                                        Register scratch1,
+                                                        Register scratch2,
+                                                        Register scratch3) {
+  Label compare_lengths, compare_lengths_1;
+
+  // Find minimum length. If either length is zero just compare lengths.
+  __ mov(scratch1, FieldOperand(left, String::kLengthOffset));
+  __ test(scratch1, Operand(scratch1));
+  __ j(zero, &compare_lengths_1);
+  __ mov(scratch2, FieldOperand(right, String::kLengthOffset));
+  __ test(scratch2, Operand(scratch2));
+  __ j(zero, &compare_lengths_1);
+  __ cmp(scratch1, Operand(scratch2));
+  if (CpuFeatures::IsSupported(CMOV)) {
+    CpuFeatures::Scope use_cmov(CMOV);
+    __ cmov(greater, scratch1, Operand(scratch2));
+  } else {
+    Label l;
+    __ j(less, &l);
+    __ mov(scratch1, scratch2);
+    __ bind(&l);
+  }
+
+  Label result_greater, result_less;
+  Label loop;
+  // Compare next character.
+  __ mov(scratch3, Immediate(-1));  // Index into strings.
+  __ bind(&loop);
+  // Compare characters.
+  Label character_compare_done;
+  __ add(Operand(scratch3), Immediate(1));
+  __ mov_b(scratch2, Operand(left,
+                             scratch3,
+                             times_1,
+                             SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ subb(scratch2, Operand(right,
+                            scratch3,
+                            times_1,
+                            SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ j(not_equal, &character_compare_done);
+  __ sub(Operand(scratch1), Immediate(1));
+  __ j(not_zero, &loop);
+  // If min length characters match compare lengths otherwise last character
+  // compare is the result.
+  __ bind(&character_compare_done);
+  __ j(equal, &compare_lengths);
+  __ j(less, &result_less);
+  __ jmp(&result_greater);
+
+  // Compare lengths.
+  Label result_not_equal;
+  __ bind(&compare_lengths);
+  __ mov(scratch1, FieldOperand(left, String::kLengthOffset));
+  __ bind(&compare_lengths_1);
+  __ sub(scratch1, FieldOperand(right, String::kLengthOffset));
+  __ j(not_zero, &result_not_equal);
+
+  // Result is EQUAL.
+  ASSERT_EQ(0, EQUAL);
+  ASSERT_EQ(0, kSmiTag);
+  __ xor_(eax, Operand(eax));
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  __ ret(2 * kPointerSize);
+  __ bind(&result_not_equal);
+  __ j(greater, &result_greater);
+
+  // Result is LESS.
+  __ bind(&result_less);
+  __ mov(eax, Immediate(Smi::FromInt(LESS)->value()));
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  __ ret(2 * kPointerSize);
+
+  // Result is GREATER.
+  __ bind(&result_greater);
+  __ mov(eax, Immediate(Smi::FromInt(GREATER)->value()));
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  __ ret(2 * kPointerSize);
+}
+
+
+void StringCompareStub::Generate(MacroAssembler* masm) {
+  Label runtime;
+
+  // Stack frame on entry.
+  //  esp[0]: return address
+  //  esp[4]: right string
+  //  esp[8]: left string
+
+  __ mov(edx, Operand(esp, 2 * kPointerSize));  // left
+  __ mov(eax, Operand(esp, 1 * kPointerSize));  // right
+
+  Label not_same;
+  __ cmp(edx, Operand(eax));
+  __ j(not_equal, &not_same);
+  ASSERT_EQ(0, EQUAL);
+  ASSERT_EQ(0, kSmiTag);
+  __ xor_(eax, Operand(eax));
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+  __ ret(2 * kPointerSize);
+
+  __ bind(&not_same);
+
+  // Check that both objects are not smis.
+  ASSERT_EQ(0, kSmiTag);
+  __ mov(ebx, Operand(edx));
+  __ and_(ebx, Operand(eax));
+  __ test(ebx, Immediate(kSmiTagMask));
+  __ j(zero, &runtime);
+
+  // Load instance type for both strings.
+  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
+  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
+  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
+  __ movzx_b(ebx, FieldOperand(ebx, Map::kInstanceTypeOffset));
+
+  // Check that both are flat ascii strings.
+  Label non_ascii_flat;
+  __ and_(ecx, kStringRepresentationMask | kStringEncodingMask);
+  __ cmp(ecx, kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &non_ascii_flat);
+  const int kFlatAsciiString =
+      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+  __ and_(ebx, kFlatAsciiString);
+  __ cmp(ebx, kStringTag | kSeqStringTag | kAsciiStringTag);
+  __ j(not_equal, &non_ascii_flat);
+
+  // Compare flat ascii strings.
+  GenerateCompareFlatAsciiStrings(masm, edx, eax, ecx, ebx, edi);
+
+  __ bind(&non_ascii_flat);
+
+  // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
+  // tagged as a small integer.
+  __ bind(&runtime);
+  __ TailCallRuntime(ExternalReference(Runtime::kStringCompare), 2, 1);
+}
+
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/ia32/codegen-ia32.h b/src/ia32/codegen-ia32.h
index 3d17c96..000222f 100644
--- a/src/ia32/codegen-ia32.h
+++ b/src/ia32/codegen-ia32.h
@@ -541,15 +541,18 @@
   // Fast support for Math.random().
   void GenerateRandomPositiveSmi(ZoneList<Expression*>* args);
 
-  // Fast support for Math.sin and Math.cos.
-  enum MathOp { SIN, COS };
-  void GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args);
-  inline void GenerateMathSin(ZoneList<Expression*>* args);
-  inline void GenerateMathCos(ZoneList<Expression*>* args);
-
   // Fast support for StringAdd.
   void GenerateStringAdd(ZoneList<Expression*>* args);
 
+  // Fast support for SubString.
+  void GenerateSubString(ZoneList<Expression*>* args);
+
+  // Fast support for StringCompare.
+  void GenerateStringCompare(ZoneList<Expression*>* args);
+
+  // Support for direct calls from JavaScript to native RegExp code.
+  void GenerateRegExpExec(ZoneList<Expression*>* args);
+
   // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,
@@ -750,7 +753,32 @@
 };
 
 
-class StringAddStub: public CodeStub {
+class StringStubBase: public CodeStub {
+ public:
+  // Generate code for copying characters using a simple loop. This should only
+  // be used in places where the number of characters is small and the
+  // additional setup and checking in GenerateCopyCharactersREP adds too much
+  // overhead. Copying of overlapping regions is not supported.
+  void GenerateCopyCharacters(MacroAssembler* masm,
+                              Register dest,
+                              Register src,
+                              Register count,
+                              Register scratch,
+                              bool ascii);
+
+  // Generate code for copying characters using the rep movs instruction.
+  // Copies ecx characters from esi to edi. Copying of overlapping regions is
+  // not supported.
+  void GenerateCopyCharactersREP(MacroAssembler* masm,
+                                 Register dest,     // Must be edi.
+                                 Register src,      // Must be esi.
+                                 Register count,    // Must be ecx.
+                                 Register scratch,  // Neither of the above.
+                                 bool ascii);
+};
+
+
+class StringAddStub: public StringStubBase {
  public:
   explicit StringAddStub(StringAddFlags flags) {
     string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
@@ -762,18 +790,45 @@
 
   void Generate(MacroAssembler* masm);
 
-  void GenerateCopyCharacters(MacroAssembler* masm,
-                              Register desc,
-                              Register src,
-                              Register count,
-                              Register scratch,
-                              bool ascii);
-
   // Should the stub check whether arguments are strings?
   bool string_check_;
 };
 
 
+class SubStringStub: public StringStubBase {
+ public:
+  SubStringStub() {}
+
+ private:
+  Major MajorKey() { return SubString; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+};
+
+
+class StringCompareStub: public StringStubBase {
+ public:
+  explicit StringCompareStub() {
+  }
+
+  // Compare two flat ascii strings and returns result in eax after popping two
+  // arguments from the stack.
+  static void GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
+                                              Register left,
+                                              Register right,
+                                              Register scratch1,
+                                              Register scratch2,
+                                              Register scratch3);
+
+ private:
+  Major MajorKey() { return StringCompare; }
+  int MinorKey() { return 0; }
+
+  void Generate(MacroAssembler* masm);
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_CODEGEN_IA32_H_
diff --git a/src/ia32/disasm-ia32.cc b/src/ia32/disasm-ia32.cc
index 375cbdf..581cdc0 100644
--- a/src/ia32/disasm-ia32.cc
+++ b/src/ia32/disasm-ia32.cc
@@ -61,6 +61,7 @@
   {0x0B, "or", REG_OPER_OP_ORDER},
   {0x1B, "sbb", REG_OPER_OP_ORDER},
   {0x29, "sub", OPER_REG_OP_ORDER},
+  {0x2A, "subb", REG_OPER_OP_ORDER},
   {0x2B, "sub", REG_OPER_OP_ORDER},
   {0x85, "test", REG_OPER_OP_ORDER},
   {0x31, "xor", OPER_REG_OP_ORDER},
@@ -1007,7 +1008,16 @@
 
       case 0x80:
         { data++;
-          AppendToBuffer("%s ", "cmpb");
+          int mod, regop, rm;
+          get_modrm(*data, &mod, &regop, &rm);
+          const char* mnem = NULL;
+          printf("%d\n", regop);
+          switch (regop) {
+            case 5:  mnem = "subb"; break;
+            case 7:  mnem = "cmpb"; break;
+            default: UnimplementedInstruction();
+          }
+          AppendToBuffer("%s ", mnem);
           data += PrintRightOperand(data);
           int32_t imm = *data;
           AppendToBuffer(",0x%x", imm);
@@ -1057,6 +1067,19 @@
                            NameOfXMMRegister(regop),
                            NameOfXMMRegister(rm));
             data++;
+          } else if (*data == 0x6F) {
+            data++;
+            int mod, regop, rm;
+            get_modrm(*data, &mod, &regop, &rm);
+            AppendToBuffer("movdqa %s,", NameOfXMMRegister(regop));
+            data += PrintRightOperand(data);
+          } else if (*data == 0x7F) {
+            AppendToBuffer("movdqa ");
+            data++;
+            int mod, regop, rm;
+            get_modrm(*data, &mod, &regop, &rm);
+            data += PrintRightOperand(data);
+            AppendToBuffer(",%s", NameOfXMMRegister(regop));
           } else {
             UnimplementedInstruction();
           }
@@ -1093,6 +1116,11 @@
         data += 2;
         break;
 
+      case 0x2C:
+        AppendToBuffer("subb eax,0x%x", *reinterpret_cast<uint8_t*>(data+1));
+        data += 2;
+        break;
+
       case 0xA9:
         AppendToBuffer("test eax,0x%x", *reinterpret_cast<int32_t*>(data+1));
         data += 5;
@@ -1163,9 +1191,29 @@
         break;
 
       case 0xF3:
-        if (*(data+1) == 0x0F && *(data+2) == 0x2C) {
-          data += 3;
-          data += PrintOperands("cvttss2si", REG_OPER_OP_ORDER, data);
+        if (*(data+1) == 0x0F) {
+          if (*(data+2) == 0x2C) {
+            data += 3;
+            data += PrintOperands("cvttss2si", REG_OPER_OP_ORDER, data);
+          } else  if (*(data+2) == 0x6F) {
+            data += 3;
+            int mod, regop, rm;
+            get_modrm(*data, &mod, &regop, &rm);
+            AppendToBuffer("movdqu %s,", NameOfXMMRegister(regop));
+            data += PrintRightOperand(data);
+          } else  if (*(data+2) == 0x7F) {
+            AppendToBuffer("movdqu ");
+            data += 3;
+            int mod, regop, rm;
+            get_modrm(*data, &mod, &regop, &rm);
+            data += PrintRightOperand(data);
+            AppendToBuffer(",%s", NameOfXMMRegister(regop));
+          } else {
+            UnimplementedInstruction();
+          }
+        } else if (*(data+1) == 0xA5) {
+          data += 2;
+          AppendToBuffer("rep_movs");
         } else {
           UnimplementedInstruction();
         }
@@ -1185,6 +1233,9 @@
   }
 
   int instr_len = data - instr;
+  if (instr_len == 0) {
+    printf("%02x", *data);
+  }
   ASSERT(instr_len > 0);  // Ensure progress.
 
   int outp = 0;
diff --git a/src/ia32/fast-codegen-ia32.cc b/src/ia32/fast-codegen-ia32.cc
index 46524d7..fdab585 100644
--- a/src/ia32/fast-codegen-ia32.cc
+++ b/src/ia32/fast-codegen-ia32.cc
@@ -194,185 +194,162 @@
 }
 
 
-void FastCodeGenerator::Move(Expression::Context context, Register source) {
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      break;
-    case Expression::kValue:
-      __ push(source);
-      break;
-    case Expression::kTest:
-      TestAndBranch(source, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      __ push(source);
-      TestAndBranch(source, true_label_, &discard);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(false_label_);
-      break;
-    }
-    case Expression::kTestValue: {
-      Label discard;
-      __ push(source);
-      TestAndBranch(source, &discard, false_label_);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(true_label_);
-    }
-  }
-}
-
-
-template <>
-Operand FastCodeGenerator::CreateSlotOperand<Operand>(Slot* source,
-                                                      Register scratch) {
-  switch (source->type()) {
-    case Slot::PARAMETER:
-    case Slot::LOCAL:
-      return Operand(ebp, SlotOffset(source));
-    case Slot::CONTEXT: {
-      int context_chain_length =
-          function_->scope()->ContextChainLength(source->var()->scope());
-      __ LoadContext(scratch, context_chain_length);
-      return CodeGenerator::ContextOperand(scratch, source->index());
-      break;
-    }
-    case Slot::LOOKUP:
-      UNIMPLEMENTED();
-      // Fall-through.
-    default:
-      UNREACHABLE();
-      return Operand(eax, 0);  // Dead code to make the compiler happy.
-  }
-}
-
-
-void FastCodeGenerator::Move(Register dst, Slot* source) {
-  Operand location = CreateSlotOperand<Operand>(source, dst);
-  __ mov(dst, location);
-}
-
-
-void FastCodeGenerator::Move(Expression::Context context,
-                             Slot* source,
-                             Register scratch) {
+void FastCodeGenerator::Apply(Expression::Context context,
+                              Slot* slot,
+                              Register scratch) {
   switch (context) {
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
       break;
     case Expression::kValue: {
-      Operand location = CreateSlotOperand<Operand>(source, scratch);
+      MemOperand location = EmitSlotSearch(slot, scratch);
       __ push(location);
       break;
     }
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
+    case Expression::kTest:
+    case Expression::kValueTest:
     case Expression::kTestValue:
-      Move(scratch, source);
-      Move(context, scratch);
+      Move(scratch, slot);
+      Apply(context, scratch);
       break;
   }
 }
 
 
-void FastCodeGenerator::Move(Expression::Context context, Literal* expr) {
+void FastCodeGenerator::Apply(Expression::Context context, Literal* lit) {
   switch (context) {
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
       break;
     case Expression::kValue:
-      __ push(Immediate(expr->handle()));
+      __ push(Immediate(lit->handle()));
       break;
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
+    case Expression::kTest:
+    case Expression::kValueTest:
     case Expression::kTestValue:
-      __ mov(eax, expr->handle());
-      Move(context, eax);
+      __ mov(eax, lit->handle());
+      Apply(context, eax);
       break;
   }
 }
 
 
+void FastCodeGenerator::ApplyTOS(Expression::Context context) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(1);
+      break;
+    case Expression::kValue:
+      break;
+    case Expression::kTest:
+      __ pop(eax);
+      TestAndBranch(eax, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      __ mov(eax, Operand(esp, 0));
+      TestAndBranch(eax, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
+      break;
+    }
+    case Expression::kTestValue: {
+      Label discard;
+      __ mov(eax, Operand(esp, 0));
+      TestAndBranch(eax, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(true_label_);
+    }
+  }
+}
+
+
+void FastCodeGenerator::DropAndApply(int count,
+                                     Expression::Context context,
+                                     Register reg) {
+  ASSERT(count > 0);
+  ASSERT(!reg.is(esp));
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(count);
+      break;
+    case Expression::kValue:
+      if (count > 1) __ Drop(count - 1);
+      __ mov(Operand(esp, 0), reg);
+      break;
+    case Expression::kTest:
+      __ Drop(count);
+      TestAndBranch(reg, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ mov(Operand(esp, 0), reg);
+      TestAndBranch(reg, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
+      break;
+    }
+    case Expression::kTestValue: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ mov(Operand(esp, 0), reg);
+      TestAndBranch(reg, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(true_label_);
+      break;
+    }
+  }
+}
+
+
+MemOperand FastCodeGenerator::EmitSlotSearch(Slot* slot, Register scratch) {
+  switch (slot->type()) {
+    case Slot::PARAMETER:
+    case Slot::LOCAL:
+      return Operand(ebp, SlotOffset(slot));
+    case Slot::CONTEXT: {
+      int context_chain_length =
+          function_->scope()->ContextChainLength(slot->var()->scope());
+      __ LoadContext(scratch, context_chain_length);
+      return CodeGenerator::ContextOperand(scratch, slot->index());
+    }
+    case Slot::LOOKUP:
+      UNREACHABLE();
+  }
+  UNREACHABLE();
+  return Operand(eax, 0);
+}
+
+
+void FastCodeGenerator::Move(Register destination, Slot* source) {
+  MemOperand location = EmitSlotSearch(source, destination);
+  __ mov(destination, location);
+}
+
+
 void FastCodeGenerator::Move(Slot* dst,
                              Register src,
                              Register scratch1,
                              Register scratch2) {
-  switch (dst->type()) {
-    case Slot::PARAMETER:
-    case Slot::LOCAL:
-      __ mov(Operand(ebp, SlotOffset(dst)), src);
-      break;
-    case Slot::CONTEXT: {
-      ASSERT(!src.is(scratch1));
-      ASSERT(!src.is(scratch2));
-      ASSERT(!scratch1.is(scratch2));
-      int context_chain_length =
-          function_->scope()->ContextChainLength(dst->var()->scope());
-      __ LoadContext(scratch1, context_chain_length);
-      __ mov(Operand(scratch1, Context::SlotOffset(dst->index())), src);
-      int offset = FixedArray::kHeaderSize + dst->index() * kPointerSize;
-      __ RecordWrite(scratch1, offset, src, scratch2);
-      break;
-    }
-    case Slot::LOOKUP:
-      UNIMPLEMENTED();
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-void FastCodeGenerator::DropAndMove(Expression::Context context,
-                                    Register source,
-                                    int count) {
-  ASSERT(count > 0);
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      __ add(Operand(esp), Immediate(count * kPointerSize));
-      break;
-    case Expression::kValue:
-      if (count > 1) {
-        __ add(Operand(esp), Immediate((count - 1) * kPointerSize));
-      }
-      __ mov(Operand(esp, 0), source);
-      break;
-    case Expression::kTest:
-      ASSERT(!source.is(esp));
-      __ add(Operand(esp), Immediate(count * kPointerSize));
-      TestAndBranch(source, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      if (count > 1) {
-        __ add(Operand(esp), Immediate((count - 1) * kPointerSize));
-      }
-      __ mov(Operand(esp, 0), source);
-      TestAndBranch(source, true_label_, &discard);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(false_label_);
-      break;
-    }
-    case Expression::kTestValue: {
-      Label discard;
-      if (count > 1) {
-        __ add(Operand(esp), Immediate((count - 1) * kPointerSize));
-      }
-      __ mov(Operand(esp, 0), source);
-      TestAndBranch(source, &discard, false_label_);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(true_label_);
-      break;
-    }
+  ASSERT(dst->type() != Slot::LOOKUP);  // Not yet implemented.
+  ASSERT(!scratch1.is(src) && !scratch2.is(src));
+  MemOperand location = EmitSlotSearch(dst, scratch1);
+  __ mov(location, src);
+  // Emit the write barrier code if the location is in the heap.
+  if (dst->type() == Slot::CONTEXT) {
+    int offset = FixedArray::kHeaderSize + dst->index() * kPointerSize;
+    __ RecordWrite(scratch1, offset, src, scratch2);
   }
 }
 
@@ -416,18 +393,21 @@
 
   if (slot != NULL) {
     switch (slot->type()) {
-      case Slot::PARAMETER:  // Fall through.
+      case Slot::PARAMETER:
       case Slot::LOCAL:
         if (decl->mode() == Variable::CONST) {
-          __ mov(Operand(ebp, SlotOffset(var->slot())),
+          __ mov(Operand(ebp, SlotOffset(slot)),
                  Immediate(Factory::the_hole_value()));
         } else if (decl->fun() != NULL) {
           Visit(decl->fun());
-          __ pop(Operand(ebp, SlotOffset(var->slot())));
+          __ pop(Operand(ebp, SlotOffset(slot)));
         }
         break;
 
       case Slot::CONTEXT:
+        // We bypass the general EmitSlotSearch because we know more about
+        // this specific context.
+
         // The variable in the decl always resides in the current context.
         ASSERT_EQ(0, function_->scope()->ContextChainLength(var->scope()));
         if (FLAG_debug_code) {
@@ -499,7 +479,7 @@
 
       // Value in eax is ignored (declarations are statements).  Receiver
       // and key on stack are discarded.
-      __ add(Operand(esp), Immediate(2 * kPointerSize));
+      __ Drop(2);
     }
   }
 }
@@ -529,7 +509,7 @@
   __ push(esi);
   __ push(Immediate(boilerplate));
   __ CallRuntime(Runtime::kNewClosure, 2);
-  Move(expr->context(), eax);
+  Apply(expr->context(), eax);
 }
 
 
@@ -556,13 +536,13 @@
     // Remember that the assembler may choose to do peephole optimization
     // (eg, push/pop elimination).
     __ nop();
-    DropAndMove(context, eax);
+    DropAndApply(1, context, eax);
   } else if (rewrite->AsSlot() != NULL) {
     Slot* slot = rewrite->AsSlot();
     if (FLAG_debug_code) {
       switch (slot->type()) {
-        case Slot::LOCAL:
-        case Slot::PARAMETER: {
+        case Slot::PARAMETER:
+        case Slot::LOCAL: {
           Comment cmnt(masm_, "Stack slot");
           break;
         }
@@ -573,46 +553,45 @@
         case Slot::LOOKUP:
           UNIMPLEMENTED();
           break;
-        default:
-          UNREACHABLE();
       }
     }
-    Move(context, slot, eax);
+    Apply(context, slot, eax);
   } else {
-    Comment cmnt(masm_, "Variable rewritten to Property");
-    // A variable has been rewritten into an explicit access to
-    // an object property.
+    Comment cmnt(masm_, "Variable rewritten to property");
+    // A variable has been rewritten into an explicit access to an object
+    // property.
     Property* property = rewrite->AsProperty();
     ASSERT_NOT_NULL(property);
 
-    // Currently the only parameter expressions that can occur are
-    // on the form "slot[literal]".
+    // The only property expressions that can occur are of the form
+    // "slot[literal]".
 
-    // Check that the object is in a slot.
+    // Assert that the object is in a slot.
     Variable* object_var = property->obj()->AsVariableProxy()->AsVariable();
     ASSERT_NOT_NULL(object_var);
     Slot* object_slot = object_var->slot();
     ASSERT_NOT_NULL(object_slot);
 
     // Load the object.
-    Move(Expression::kValue, object_slot, eax);
+    MemOperand object_loc = EmitSlotSearch(object_slot, eax);
+    __ push(object_loc);
 
-    // Check that the key is a smi.
+    // Assert that the key is a smi.
     Literal* key_literal = property->key()->AsLiteral();
     ASSERT_NOT_NULL(key_literal);
     ASSERT(key_literal->handle()->IsSmi());
 
     // Load the key.
-    Move(Expression::kValue, key_literal);
+    __ push(Immediate(key_literal->handle()));
 
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
-    // Notice: We must not have a "test eax, ..." instruction after
-    // the call. It is treated specially by the LoadIC code.
+    // Notice: We must not have a "test eax, ..." instruction after the
+    // call. It is treated specially by the LoadIC code.
     __ nop();
     // Drop key and object left on the stack by IC.
-    DropAndMove(context, eax, 2);
+    DropAndApply(2, context, eax);
   }
 }
 
@@ -640,7 +619,7 @@
   __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   // Label done:
   __ bind(&done);
-  Move(expr->context(), eax);
+  Apply(expr->context(), eax);
 }
 
 
@@ -672,7 +651,7 @@
       result_saved = true;
     }
     switch (property->kind()) {
-      case ObjectLiteral::Property::MATERIALIZED_LITERAL:  // fall through
+      case ObjectLiteral::Property::MATERIALIZED_LITERAL:  // Fall through.
         ASSERT(!CompileTimeValue::IsCompileTimeValue(value));
       case ObjectLiteral::Property::COMPUTED:
         if (key->handle()->IsSymbol()) {
@@ -686,7 +665,7 @@
           __ mov(eax, Operand(esp, 0));  // Restore result into eax.
           break;
         }
-        // fall through
+        // Fall through.
       case ObjectLiteral::Property::PROTOTYPE:
         __ push(eax);
         Visit(key);
@@ -696,7 +675,7 @@
         __ CallRuntime(Runtime::kSetProperty, 3);
         __ mov(eax, Operand(esp, 0));  // Restore result into eax.
         break;
-      case ObjectLiteral::Property::SETTER:  // fall through
+      case ObjectLiteral::Property::SETTER:
       case ObjectLiteral::Property::GETTER:
         __ push(eax);
         Visit(key);
@@ -716,7 +695,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ add(Operand(esp), Immediate(kPointerSize));
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(eax);
@@ -730,7 +709,7 @@
       if (!result_saved) __ push(eax);
       TestAndBranch(eax, true_label_, &discard);
       __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -739,7 +718,7 @@
       if (!result_saved) __ push(eax);
       TestAndBranch(eax, &discard, false_label_);
       __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -752,7 +731,7 @@
   __ mov(ebx, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
   __ push(FieldOperand(ebx, JSFunction::kLiteralsOffset));
   __ push(Immediate(Smi::FromInt(expr->literal_index())));
-  __ push(Immediate(expr->literals()));
+  __ push(Immediate(expr->constant_elements()));
   if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateArrayLiteral, 3);
   } else {
@@ -795,7 +774,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ add(Operand(esp), Immediate(kPointerSize));
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(eax);
@@ -809,7 +788,7 @@
       if (!result_saved) __ push(eax);
       TestAndBranch(eax, true_label_, &discard);
       __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -818,7 +797,7 @@
       if (!result_saved) __ push(eax);
       TestAndBranch(eax, &discard, false_label_);
       __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -828,18 +807,21 @@
 
 void FastCodeGenerator::EmitNamedPropertyLoad(Property* prop,
                                               Expression::Context context) {
+  SetSourcePosition(prop->position());
   Literal* key = prop->key()->AsLiteral();
   __ mov(ecx, Immediate(key->handle()));
   Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
   __ call(ic, RelocInfo::CODE_TARGET);
-  Move(context, eax);
+  Apply(context, eax);
 }
 
 
-void FastCodeGenerator::EmitKeyedPropertyLoad(Expression::Context context) {
+void FastCodeGenerator::EmitKeyedPropertyLoad(Property* prop,
+                                              Expression::Context context) {
+  SetSourcePosition(prop->position());
   Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
   __ call(ic, RelocInfo::CODE_TARGET);
-  Move(context, eax);
+  Apply(context, eax);
 }
 
 
@@ -849,12 +831,12 @@
                            NO_OVERWRITE,
                            NO_GENERIC_BINARY_FLAGS);
   __ CallStub(&stub);
-  Move(context, eax);
+  Apply(context, eax);
 }
 
 
-void FastCodeGenerator::EmitVariableAssignment(Assignment* expr) {
-  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
+void FastCodeGenerator::EmitVariableAssignment(Variable* var,
+                                               Expression::Context context) {
   ASSERT(var != NULL);
   ASSERT(var->is_global() || var->slot() != NULL);
   if (var->is_global()) {
@@ -867,15 +849,15 @@
     Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
     // Overwrite the receiver on the stack with the result if needed.
-    DropAndMove(expr->context(), eax);
+    DropAndApply(1, context, eax);
 
   } else if (var->slot() != NULL) {
     Slot* slot = var->slot();
     switch (slot->type()) {
       case Slot::LOCAL:
       case Slot::PARAMETER: {
-        Operand target = Operand(ebp, SlotOffset(var->slot()));
-        switch (expr->context()) {
+        Operand target = Operand(ebp, SlotOffset(slot));
+        switch (context) {
           case Expression::kUninitialized:
             UNREACHABLE();
           case Expression::kEffect:
@@ -899,7 +881,7 @@
             __ mov(target, eax);
             TestAndBranch(eax, true_label_, &discard);
             __ bind(&discard);
-            __ add(Operand(esp), Immediate(kPointerSize));
+            __ Drop(1);
             __ jmp(false_label_);
             break;
           }
@@ -909,7 +891,7 @@
             __ mov(target, eax);
             TestAndBranch(eax, &discard, false_label_);
             __ bind(&discard);
-            __ add(Operand(esp), Immediate(kPointerSize));
+            __ Drop(1);
             __ jmp(true_label_);
             break;
           }
@@ -918,41 +900,20 @@
       }
 
       case Slot::CONTEXT: {
-        int chain_length =
-            function_->scope()->ContextChainLength(slot->var()->scope());
-        if (chain_length > 0) {
-          // Move up the context chain to the context containing the slot.
-          __ mov(eax,
-                  Operand(esi, Context::SlotOffset(Context::CLOSURE_INDEX)));
-          // Load the function context (which is the incoming, outer context).
-          __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
-          for (int i = 1; i < chain_length; i++) {
-            __ mov(eax,
-                    Operand(eax, Context::SlotOffset(Context::CLOSURE_INDEX)));
-            __ mov(eax, FieldOperand(eax, JSFunction::kContextOffset));
-          }
-        } else {  // Slot is in the current context.  Generate optimized code.
-          __ mov(eax, esi);  // RecordWrite destroys the object register.
-        }
-        if (FLAG_debug_code) {
-          __ cmp(eax,
-                  Operand(eax, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-          __ Check(equal, "Context Slot chain length wrong.");
-        }
-        __ pop(ecx);
-        __ mov(Operand(eax, Context::SlotOffset(slot->index())), ecx);
+        MemOperand target = EmitSlotSearch(slot, ecx);
+        __ pop(eax);
+        __ mov(target, eax);
 
         // RecordWrite may destroy all its register arguments.
-        if (expr->context() == Expression::kValue) {
-          __ push(ecx);
-        } else if (expr->context() != Expression::kEffect) {
-          __ mov(edx, ecx);
+        if (context == Expression::kValue) {
+          __ push(eax);
+        } else if (context != Expression::kEffect) {
+          __ mov(edx, eax);
         }
         int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
-        __ RecordWrite(eax, offset, ecx, ebx);
-        if (expr->context() != Expression::kEffect &&
-            expr->context() != Expression::kValue) {
-          Move(expr->context(), edx);
+        __ RecordWrite(ecx, offset, eax, ebx);
+        if (context != Expression::kEffect && context != Expression::kValue) {
+          Apply(context, edx);
         }
         break;
       }
@@ -961,6 +922,10 @@
         UNREACHABLE();
         break;
     }
+  } else {
+    // Variables rewritten as properties are not treated as variables in
+    // assignments.
+    UNREACHABLE();
   }
 }
 
@@ -992,7 +957,7 @@
     __ pop(eax);
   }
 
-  DropAndMove(expr->context(), eax);
+  DropAndApply(1, expr->context(), eax);
 }
 
 
@@ -1025,34 +990,32 @@
   }
 
   // Receiver and key are still on stack.
-  __ add(Operand(esp), Immediate(2 * kPointerSize));
-  Move(expr->context(), eax);
+  DropAndApply(2, expr->context(), eax);
 }
 
 
 void FastCodeGenerator::VisitProperty(Property* expr) {
   Comment cmnt(masm_, "[ Property");
   Expression* key = expr->key();
-  uint32_t dummy;
 
   // Record the source position for the property load.
   SetSourcePosition(expr->position());
 
-  // Evaluate receiver.
+  // Evaluate the receiver.
   Visit(expr->obj());
 
-  if (key->AsLiteral() != NULL && key->AsLiteral()->handle()->IsSymbol() &&
-      !String::cast(*(key->AsLiteral()->handle()))->AsArrayIndex(&dummy)) {
-    // Do a NAMED property load.
-    // The IC expects the property name in ecx and the receiver on the stack.
+  if (key->IsPropertyName()) {
+    // Do a named property load.  The IC expects the property name in ecx
+    // and the receiver on the stack.
     __ mov(ecx, Immediate(key->AsLiteral()->handle()));
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
     // By emitting a nop we make sure that we do not have a test eax
     // instruction after the call it is treated specially by the LoadIC code.
     __ nop();
+    DropAndApply(1, expr->context(), eax);
   } else {
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Visit(expr->key());
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
@@ -1060,9 +1023,8 @@
     // instruction after the call it is treated specially by the LoadIC code.
     __ nop();
     // Drop key left on the stack by IC.
-    __ add(Operand(esp), Immediate(kPointerSize));
+    DropAndApply(2, expr->context(), eax);
   }
-  DropAndMove(expr->context(), eax);
 }
 
 
@@ -1084,7 +1046,7 @@
   __ call(ic, mode);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  Move(expr->context(), eax);
+  Apply(expr->context(), eax);
 }
 
 
@@ -1101,7 +1063,7 @@
   __ CallStub(&stub);
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
-  DropAndMove(expr->context(), eax);
+  DropAndApply(1, expr->context(), eax);
 }
 
 
@@ -1142,14 +1104,15 @@
       // instruction after the call it is treated specially by the LoadIC code.
       __ nop();
       // Drop key left on the stack by IC.
-      __ add(Operand(esp), Immediate(kPointerSize));
+      __ Drop(1);
       // Pop receiver.
       __ pop(ebx);
       // Push result (function).
       __ push(eax);
       // Push receiver object on stack.
       if (prop->is_synthetic()) {
-        __ push(CodeGenerator::GlobalObject());
+        __ mov(ecx, CodeGenerator::GlobalObject());
+        __ push(FieldOperand(ecx, GlobalObject::kGlobalReceiverOffset));
       } else {
         __ push(ebx);
       }
@@ -1210,7 +1173,7 @@
   __ call(construct_builtin, RelocInfo::CONSTRUCT_CALL);
 
   // Replace function on TOS with result in eax, or pop it.
-  DropAndMove(expr->context(), eax);
+  DropAndApply(1, expr->context(), eax);
 }
 
 
@@ -1243,7 +1206,7 @@
     // Call the C runtime function.
     __ CallRuntime(expr->function(), arg_count);
   }
-  Move(expr->context(), eax);
+  Apply(expr->context(), eax);
 }
 
 
@@ -1266,7 +1229,7 @@
           // Value is false so it's needed.
           __ push(Immediate(Factory::undefined_value()));
           // Fall through.
-        case Expression::kTest:  // Fall through.
+        case Expression::kTest:
         case Expression::kValueTest:
           __ jmp(false_label_);
           break;
@@ -1278,20 +1241,19 @@
       Comment cmnt(masm_, "[ UnaryOperation (NOT)");
       ASSERT_EQ(Expression::kTest, expr->expression()->context());
 
-      Label push_true;
-      Label push_false;
-      Label done;
-      Label* saved_true = true_label_;
-      Label* saved_false = false_label_;
+      Label push_true, push_false, done;
       switch (expr->context()) {
         case Expression::kUninitialized:
           UNREACHABLE();
           break;
 
+        case Expression::kEffect:
+          VisitForControl(expr->expression(), &done, &done);
+          __ bind(&done);
+          break;
+
         case Expression::kValue:
-          true_label_ = &push_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, &push_true);
           __ bind(&push_true);
           __ push(Immediate(Factory::true_value()));
           __ jmp(&done);
@@ -1300,39 +1262,24 @@
           __ bind(&done);
           break;
 
-        case Expression::kEffect:
-          true_label_ = &done;
-          false_label_ = &done;
-          Visit(expr->expression());
-          __ bind(&done);
-          break;
-
         case Expression::kTest:
-          true_label_ = saved_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, true_label_);
           break;
 
         case Expression::kValueTest:
-          true_label_ = saved_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, &push_true);
           __ bind(&push_true);
           __ push(Immediate(Factory::true_value()));
-          __ jmp(saved_true);
+          __ jmp(true_label_);
           break;
 
         case Expression::kTestValue:
-          true_label_ = &push_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, true_label_);
           __ bind(&push_false);
           __ push(Immediate(Factory::false_value()));
-          __ jmp(saved_false);
+          __ jmp(false_label_);
           break;
       }
-      true_label_ = saved_true;
-      false_label_ = saved_false;
       break;
     }
 
@@ -1365,7 +1312,7 @@
       }
 
       __ CallRuntime(Runtime::kTypeof, 1);
-      Move(expr->context(), eax);
+      Apply(expr->context(), eax);
       break;
     }
 
@@ -1377,27 +1324,75 @@
 
 void FastCodeGenerator::VisitCountOperation(CountOperation* expr) {
   Comment cmnt(masm_, "[ CountOperation");
-  VariableProxy* proxy = expr->expression()->AsVariableProxy();
-  ASSERT(proxy->AsVariable() != NULL);
-  ASSERT(proxy->AsVariable()->is_global());
 
-  Visit(proxy);
+  // Expression can only be a property, a global or a (parameter or local)
+  // slot. Variables with rewrite to .arguments are treated as KEYED_PROPERTY.
+  enum LhsKind { VARIABLE, NAMED_PROPERTY, KEYED_PROPERTY };
+  LhsKind assign_type = VARIABLE;
+  Property* prop = expr->expression()->AsProperty();
+  // In case of a property we use the uninitialized expression context
+  // of the key to detect a named property.
+  if (prop != NULL) {
+    assign_type = (prop->key()->context() == Expression::kUninitialized)
+        ? NAMED_PROPERTY
+        : KEYED_PROPERTY;
+  }
+
+  // Evaluate expression and get value.
+  if (assign_type == VARIABLE) {
+    ASSERT(expr->expression()->AsVariableProxy()->var() != NULL);
+    EmitVariableLoad(expr->expression()->AsVariableProxy()->var(),
+                     Expression::kValue);
+  } else  {
+    // Reserve space for result of postfix operation.
+    if (expr->is_postfix() && expr->context() != Expression::kEffect) {
+      ASSERT(expr->context() != Expression::kUninitialized);
+      __ push(Immediate(Smi::FromInt(0)));
+    }
+    Visit(prop->obj());
+    ASSERT_EQ(Expression::kValue, prop->obj()->context());
+    if (assign_type == NAMED_PROPERTY) {
+      EmitNamedPropertyLoad(prop, Expression::kValue);
+    } else {
+      Visit(prop->key());
+      ASSERT_EQ(Expression::kValue, prop->key()->context());
+      EmitKeyedPropertyLoad(prop, Expression::kValue);
+    }
+  }
+
+  // Convert to number.
   __ InvokeBuiltin(Builtins::TO_NUMBER, CALL_FUNCTION);
 
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kValue:  // Fall through
-    case Expression::kTest:  // Fall through
-    case Expression::kTestValue:  // Fall through
-    case Expression::kValueTest:
-      // Duplicate the result on the stack.
-      __ push(eax);
-      break;
-    case Expression::kEffect:
-      // Do not save result.
-      break;
+  // Save result for postfix expressions.
+  if (expr->is_postfix()) {
+    switch (expr->context()) {
+      case Expression::kUninitialized:
+        UNREACHABLE();
+      case Expression::kEffect:
+        // Do not save result.
+        break;
+      case Expression::kValue:
+      case Expression::kTest:
+      case Expression::kTestValue:
+      case Expression::kValueTest:
+        // Save the result on the stack. If we have a named or keyed property
+        // we store the result under the receiver that is currently on top
+        // of the stack.
+        switch (assign_type) {
+          case VARIABLE:
+            __ push(eax);
+            break;
+          case NAMED_PROPERTY:
+            __ mov(Operand(esp, kPointerSize), eax);
+            break;
+          case KEYED_PROPERTY:
+            __ mov(Operand(esp, 2 * kPointerSize), eax);
+            break;
+        }
+        break;
+    }
   }
+
   // Call runtime for +1/-1.
   __ push(eax);
   __ push(Immediate(Smi::FromInt(1)));
@@ -1406,42 +1401,55 @@
   } else {
     __ CallRuntime(Runtime::kNumberSub, 2);
   }
-  // Call Store IC.
-  __ mov(ecx, proxy->AsVariable()->name());
-  __ push(CodeGenerator::GlobalObject());
-  Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
-  __ call(ic, RelocInfo::CODE_TARGET);
-  // Restore up stack after store IC.
-  __ add(Operand(esp), Immediate(kPointerSize));
 
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:  // Fall through
-    case Expression::kValue:
-      // Do nothing. Result in either on the stack for value context
-      // or discarded for effect context.
+  // Store the value returned in eax.
+  switch (assign_type) {
+    case VARIABLE:
+      __ push(eax);
+      if (expr->is_postfix()) {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               Expression::kEffect);
+        // For all contexts except kEffect: We have the result on
+        // top of the stack.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               expr->context());
+      }
       break;
-    case Expression::kTest:
-      __ pop(eax);
-      TestAndBranch(eax, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      __ mov(eax, Operand(esp, 0));
-      TestAndBranch(eax, true_label_, &discard);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(false_label_);
+    case NAMED_PROPERTY: {
+      __ mov(ecx, prop->key()->AsLiteral()->handle());
+      Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
+      __ call(ic, RelocInfo::CODE_TARGET);
+      // This nop signals to the IC that there is no inlined code at the call
+      // site for it to patch.
+      __ nop();
+      if (expr->is_postfix()) {
+        __ Drop(1);  // Result is on the stack under the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(1, expr->context(), eax);
+      }
       break;
     }
-    case Expression::kTestValue: {
-      Label discard;
-      __ mov(eax, Operand(esp, 0));
-      TestAndBranch(eax, &discard, false_label_);
-      __ bind(&discard);
-      __ add(Operand(esp), Immediate(kPointerSize));
-      __ jmp(true_label_);
+    case KEYED_PROPERTY: {
+      Handle<Code> ic(Builtins::builtin(Builtins::KeyedStoreIC_Initialize));
+      __ call(ic, RelocInfo::CODE_TARGET);
+      // This nop signals to the IC that there is no inlined code at the call
+      // site for it to patch.
+      __ nop();
+      if (expr->is_postfix()) {
+        __ Drop(2);  // Result is on the stack under the key and the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(2, expr->context(), eax);
+      }
       break;
     }
   }
@@ -1483,7 +1491,7 @@
                                NO_OVERWRITE,
                                NO_GENERIC_BINARY_FLAGS);
       __ CallStub(&stub);
-      Move(expr->context(), eax);
+      Apply(expr->context(), eax);
 
       break;
     }
@@ -1500,46 +1508,40 @@
   Visit(expr->left());
   Visit(expr->right());
 
-  // Convert current context to test context: Pre-test code.
-  Label push_true;
-  Label push_false;
-  Label done;
-  Label* saved_true = true_label_;
-  Label* saved_false = false_label_;
+  // Always perform the comparison for its control flow.  Pack the result
+  // into the expression's context after the comparison is performed.
+  Label push_true, push_false, done;
+  // Initially assume we are in a test context.
+  Label* if_true = true_label_;
+  Label* if_false = false_label_;
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
-
-    case Expression::kValue:
-      true_label_ = &push_true;
-      false_label_ = &push_false;
-      break;
-
     case Expression::kEffect:
-      true_label_ = &done;
-      false_label_ = &done;
+      if_true = &done;
+      if_false = &done;
       break;
-
+    case Expression::kValue:
+      if_true = &push_true;
+      if_false = &push_false;
+      break;
     case Expression::kTest:
       break;
-
     case Expression::kValueTest:
-      true_label_ = &push_true;
+      if_true = &push_true;
       break;
-
     case Expression::kTestValue:
-      false_label_ = &push_false;
+      if_false = &push_false;
       break;
   }
-  // Convert current context to test context: End pre-test code.
 
   switch (expr->op()) {
     case Token::IN: {
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
       __ cmp(eax, Factory::true_value());
-      __ j(equal, true_label_);
-      __ jmp(false_label_);
+      __ j(equal, if_true);
+      __ jmp(if_false);
       break;
     }
 
@@ -1547,8 +1549,8 @@
       InstanceofStub stub;
       __ CallStub(&stub);
       __ test(eax, Operand(eax));
-      __ j(zero, true_label_);  // The stub returns 0 for true.
-      __ jmp(false_label_);
+      __ j(zero, if_true);  // The stub returns 0 for true.
+      __ jmp(if_false);
       break;
     }
 
@@ -1600,24 +1602,29 @@
       __ test(ecx, Immediate(kSmiTagMask));
       __ j(not_zero, &slow_case, not_taken);
       __ cmp(edx, Operand(eax));
-      __ j(cc, true_label_);
-      __ jmp(false_label_);
+      __ j(cc, if_true);
+      __ jmp(if_false);
 
       __ bind(&slow_case);
       CompareStub stub(cc, strict);
       __ CallStub(&stub);
       __ test(eax, Operand(eax));
-      __ j(cc, true_label_);
-      __ jmp(false_label_);
+      __ j(cc, if_true);
+      __ jmp(if_false);
     }
   }
 
-  // Convert current context to test context: Post-test code.
+  // Convert the result of the comparison into one expected for this
+  // expression's context.
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
 
+    case Expression::kEffect:
+      __ bind(&done);
+      break;
+
     case Expression::kValue:
       __ bind(&push_true);
       __ push(Immediate(Factory::true_value()));
@@ -1627,34 +1634,27 @@
       __ bind(&done);
       break;
 
-    case Expression::kEffect:
-      __ bind(&done);
-      break;
-
     case Expression::kTest:
       break;
 
     case Expression::kValueTest:
       __ bind(&push_true);
       __ push(Immediate(Factory::true_value()));
-      __ jmp(saved_true);
+      __ jmp(true_label_);
       break;
 
     case Expression::kTestValue:
       __ bind(&push_false);
       __ push(Immediate(Factory::false_value()));
-      __ jmp(saved_false);
+      __ jmp(false_label_);
       break;
   }
-  true_label_ = saved_true;
-  false_label_ = saved_false;
-  // Convert current context to test context: End post-test code.
 }
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ mov(eax, Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
-  Move(expr->context(), eax);
+  Apply(expr->context(), eax);
 }
 
 
@@ -1706,11 +1706,6 @@
 }
 
 
-void FastCodeGenerator::ThrowException() {
-  __ push(result_register());
-  __ CallRuntime(Runtime::kThrow, 1);
-}
-
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/ia32/ic-ia32.cc b/src/ia32/ic-ia32.cc
index 58fe2dc..5658605 100644
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@@ -313,6 +313,7 @@
 
   // Is the string a symbol?
   __ movzx_b(ebx, FieldOperand(edx, Map::kInstanceTypeOffset));
+  ASSERT(kSymbolTag != 0);
   __ test(ebx, Immediate(kIsSymbolMask));
   __ j(zero, &slow, not_taken);
 
@@ -391,6 +392,48 @@
 }
 
 
+void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- esp[0] : return address
+  //  -- esp[4] : key
+  //  -- esp[8] : receiver
+  // -----------------------------------
+  Label miss, index_ok;
+
+  // Pop return address.
+  // Performing the load early is better in the common case.
+  __ pop(eax);
+
+  __ mov(ebx, Operand(esp, 1 * kPointerSize));
+  __ test(ebx, Immediate(kSmiTagMask));
+  __ j(zero, &miss);
+  __ mov(ecx, FieldOperand(ebx, HeapObject::kMapOffset));
+  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
+  __ test(ecx, Immediate(kIsNotStringMask));
+  __ j(not_zero, &miss);
+
+  // Check if key is a smi or a heap number.
+  __ mov(edx, Operand(esp, 0));
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(zero, &index_ok);
+  __ mov(ecx, FieldOperand(ebx, HeapObject::kMapOffset));
+  __ cmp(ecx, Factory::heap_number_map());
+  __ j(not_equal, &miss);
+
+  __ bind(&index_ok);
+  // Duplicate receiver and key since they are expected on the stack after
+  // the KeyedLoadIC call.
+  __ push(ebx);  // receiver
+  __ push(edx);  // key
+  __ push(eax);  // return address
+  __ InvokeBuiltin(Builtins::STRING_CHAR_AT, JUMP_FUNCTION);
+
+  __ bind(&miss);
+  __ push(eax);
+  GenerateMiss(masm);
+}
+
+
 void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
                                         ExternalArrayType array_type) {
   // ----------- S t a t e -------------
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 3ecbcee..d7c7d3a 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -325,6 +325,17 @@
 }
 
 
+Condition MacroAssembler::IsObjectStringType(Register heap_object,
+                                             Register map,
+                                             Register instance_type) {
+  mov(map, FieldOperand(heap_object, HeapObject::kMapOffset));
+  movzx_b(instance_type, FieldOperand(map, Map::kInstanceTypeOffset));
+  ASSERT(kNotStringTag != 0);
+  test(instance_type, Immediate(kIsNotStringMask));
+  return zero;
+}
+
+
 void MacroAssembler::FCmp() {
   if (CpuFeatures::IsSupported(CMOV)) {
     fucomip();
@@ -729,13 +740,13 @@
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required, not_taken);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
-    or_(Operand(result), Immediate(kHeapObjectTag));
+    lea(result, Operand(result, kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
 }
 
 
@@ -759,13 +770,13 @@
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
-    or_(Operand(result), Immediate(kHeapObjectTag));
+    lea(result, Operand(result, kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
 }
 
 
@@ -790,13 +801,13 @@
   cmp(result_end, Operand::StaticVariable(new_space_allocation_limit));
   j(above, gc_required, not_taken);
 
-  // Update allocation top.
-  UpdateAllocationTopHelper(result_end, scratch);
-
   // Tag result if requested.
   if ((flags & TAG_OBJECT) != 0) {
-    or_(Operand(result), Immediate(kHeapObjectTag));
+    lea(result, Operand(result, kHeapObjectTag));
   }
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
 }
 
 
diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
index bc7c0f8..ceecebf 100644
--- a/src/ia32/macro-assembler-ia32.h
+++ b/src/ia32/macro-assembler-ia32.h
@@ -33,10 +33,13 @@
 namespace v8 {
 namespace internal {
 
+// Convenience for platform-independent signatures.  We do not normally
+// distinguish memory operands from other operands on ia32.
+typedef Operand MemOperand;
+
 // Forward declaration.
 class JumpTarget;
 
-
 // MacroAssembler implements a collection of frequently used macros.
 class MacroAssembler: public Assembler {
  public:
@@ -138,10 +141,28 @@
   // Compare instance type for map.
   void CmpInstanceType(Register map, InstanceType type);
 
+  // Check if the object in register heap_object is a string. Afterwards the
+  // register map contains the object map and the register instance_type
+  // contains the instance_type. The registers map and instance_type can be the
+  // same in which case it contains the instance type afterwards. Either of the
+  // registers map and instance_type can be the same as heap_object.
+  Condition IsObjectStringType(Register heap_object,
+                               Register map,
+                               Register instance_type);
+
   // FCmp is similar to integer cmp, but requires unsigned
   // jcc instructions (je, ja, jae, jb, jbe, je, and jz).
   void FCmp();
 
+  // Smi tagging support.
+  void SmiTag(Register reg) {
+    ASSERT(kSmiTag == 0);
+    shl(reg, kSmiTagSize);
+  }
+  void SmiUntag(Register reg) {
+    sar(reg, kSmiTagSize);
+  }
+
   // ---------------------------------------------------------------------------
   // Exception handling
 
@@ -347,6 +368,8 @@
 
   void Ret();
 
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the esp register.
   void Drop(int element_count);
 
   void Call(Label* target) { call(target); }
diff --git a/src/ia32/regexp-macro-assembler-ia32.cc b/src/ia32/regexp-macro-assembler-ia32.cc
index 2e13d8a..e41f9c3 100644
--- a/src/ia32/regexp-macro-assembler-ia32.cc
+++ b/src/ia32/regexp-macro-assembler-ia32.cc
@@ -55,13 +55,17 @@
  *
  * Each call to a public method should retain this convention.
  * The stack will have the following structure:
- *       - stack_area_base     (High end of the memory area to use as
- *                             backtracking stack)
- *       - at_start           (if 1, start at start of string, if 0, don't)
- *       - int* capture_array (int[num_saved_registers_], for output).
- *       - end of input       (Address of end of string)
- *       - start of input     (Address of first character in string)
- *       - void* input_string (location of a handle containing the string)
+ *       - direct_call          (if 1, direct call from JavaScript code, if 0
+ *                               call through the runtime system)
+ *       - stack_area_base      (High end of the memory area to use as
+ *                               backtracking stack)
+ *       - at_start             (if 1, we are starting at the start of the
+ *                               string, otherwise 0)
+ *       - int* capture_array   (int[num_saved_registers_], for output).
+ *       - end of input         (Address of end of string)
+ *       - start of input       (Address of first character in string)
+ *       - start index          (character index of start)
+ *       - String* input_string (location of a handle containing the string)
  *       --- frame alignment (if applicable) ---
  *       - return address
  * ebp-> - old ebp
@@ -81,11 +85,13 @@
  * The data up to the return address must be placed there by the calling
  * code, by calling the code entry as cast to a function with the signature:
  * int (*match)(String* input_string,
+ *              int start_index,
  *              Address start,
  *              Address end,
  *              int* capture_output_array,
  *              bool at_start,
- *              byte* stack_area_base)
+ *              byte* stack_area_base,
+ *              bool direct_call)
  */
 
 #define __ ACCESS_MASM(masm_)
@@ -471,8 +477,6 @@
 
 
 bool RegExpMacroAssemblerIA32::CheckSpecialCharacterClass(uc16 type,
-                                                          int cp_offset,
-                                                          bool check_offset,
                                                           Label* on_no_match) {
   // Range checks (c in min..max) are generally implemented by an unsigned
   // (c - min) <= (max - min) check
@@ -481,17 +485,12 @@
     // Match space-characters
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
-      if (check_offset) {
-        LoadCurrentCharacter(cp_offset, on_no_match);
-      } else {
-        LoadCurrentCharacterUnchecked(cp_offset, 1);
-      }
       Label success;
       __ cmp(current_character(), ' ');
       __ j(equal, &success);
       // Check range 0x09..0x0d
-      __ sub(Operand(current_character()), Immediate('\t'));
-      __ cmp(current_character(), '\r' - '\t');
+      __ lea(eax, Operand(current_character(), -'\t'));
+      __ cmp(eax, '\r' - '\t');
       BranchOrBacktrack(above, on_no_match);
       __ bind(&success);
       return true;
@@ -499,72 +498,118 @@
     return false;
   case 'S':
     // Match non-space characters.
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
       __ cmp(current_character(), ' ');
       BranchOrBacktrack(equal, on_no_match);
-      __ sub(Operand(current_character()), Immediate('\t'));
-      __ cmp(current_character(), '\r' - '\t');
+      __ lea(eax, Operand(current_character(), -'\t'));
+      __ cmp(eax, '\r' - '\t');
       BranchOrBacktrack(below_equal, on_no_match);
       return true;
     }
     return false;
   case 'd':
     // Match ASCII digits ('0'..'9')
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ sub(Operand(current_character()), Immediate('0'));
-    __ cmp(current_character(), '9' - '0');
+    __ lea(eax, Operand(current_character(), -'0'));
+    __ cmp(eax, '9' - '0');
     BranchOrBacktrack(above, on_no_match);
     return true;
   case 'D':
     // Match non ASCII-digits
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ sub(Operand(current_character()), Immediate('0'));
-    __ cmp(current_character(), '9' - '0');
+    __ lea(eax, Operand(current_character(), -'0'));
+    __ cmp(eax, '9' - '0');
     BranchOrBacktrack(below_equal, on_no_match);
     return true;
   case '.': {
     // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ xor_(Operand(current_character()), Immediate(0x01));
+    __ mov(Operand(eax), current_character());
+    __ xor_(Operand(eax), Immediate(0x01));
     // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
-    __ sub(Operand(current_character()), Immediate(0x0b));
-    __ cmp(current_character(), 0x0c - 0x0b);
+    __ sub(Operand(eax), Immediate(0x0b));
+    __ cmp(eax, 0x0c - 0x0b);
     BranchOrBacktrack(below_equal, on_no_match);
     if (mode_ == UC16) {
       // Compare original value to 0x2028 and 0x2029, using the already
       // computed (current_char ^ 0x01 - 0x0b). I.e., check for
       // 0x201d (0x2028 - 0x0b) or 0x201e.
-      __ sub(Operand(current_character()), Immediate(0x2028 - 0x0b));
-      __ cmp(current_character(), 1);
+      __ sub(Operand(eax), Immediate(0x2028 - 0x0b));
+      __ cmp(eax, 0x2029 - 0x2028);
       BranchOrBacktrack(below_equal, on_no_match);
     }
     return true;
   }
+  case 'w': {
+    Label done, check_digits;
+    __ cmp(Operand(current_character()), Immediate('9'));
+    __ j(less_equal, &check_digits);
+    __ cmp(Operand(current_character()), Immediate('_'));
+    __ j(equal, &done);
+    // Convert to lower case if letter.
+    __ mov(Operand(eax), current_character());
+    __ or_(eax, 0x20);
+    // check current character in range ['a'..'z'], nondestructively.
+    __ sub(Operand(eax), Immediate('a'));
+    __ cmp(Operand(eax), Immediate('z' - 'a'));
+    BranchOrBacktrack(above, on_no_match);
+    __ jmp(&done);
+    __ bind(&check_digits);
+    // Check current character in range ['0'..'9'].
+    __ cmp(Operand(current_character()), Immediate('0'));
+    BranchOrBacktrack(below, on_no_match);
+    __ bind(&done);
+
+    return true;
+  }
+  case 'W': {
+    Label done, check_digits;
+    __ cmp(Operand(current_character()), Immediate('9'));
+    __ j(less_equal, &check_digits);
+    __ cmp(Operand(current_character()), Immediate('_'));
+    BranchOrBacktrack(equal, on_no_match);
+    // Convert to lower case if letter.
+    __ mov(Operand(eax), current_character());
+    __ or_(eax, 0x20);
+    // check current character in range ['a'..'z'], nondestructively.
+    __ sub(Operand(eax), Immediate('a'));
+    __ cmp(Operand(eax), Immediate('z' - 'a'));
+    BranchOrBacktrack(below_equal, on_no_match);
+    __ jmp(&done);
+    __ bind(&check_digits);
+    // Check current character in range ['0'..'9'].
+    __ cmp(Operand(current_character()), Immediate('0'));
+    BranchOrBacktrack(above_equal, on_no_match);
+    __ bind(&done);
+    return true;
+  }
+  // Non-standard classes (with no syntactic shorthand) used internally.
   case '*':
     // Match any character.
-    if (check_offset) {
-      CheckPosition(cp_offset, on_no_match);
+    return true;
+  case 'n': {
+    // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 or 0x2029).
+    // The opposite of '.'.
+    __ mov(Operand(eax), current_character());
+    __ xor_(Operand(eax), Immediate(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ sub(Operand(eax), Immediate(0x0b));
+    __ cmp(eax, 0x0c - 0x0b);
+    if (mode_ == ASCII) {
+      BranchOrBacktrack(above, on_no_match);
+    } else {
+      Label done;
+      BranchOrBacktrack(below_equal, &done);
+      ASSERT_EQ(UC16, mode_);
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ sub(Operand(eax), Immediate(0x2028 - 0x0b));
+      __ cmp(eax, 1);
+      BranchOrBacktrack(above, on_no_match);
+      __ bind(&done);
     }
     return true;
-  // No custom implementation (yet): w, W, s(UC16), S(UC16).
+  }
+  // No custom implementation (yet): s(UC16), S(UC16).
   default:
     return false;
   }
@@ -942,6 +987,12 @@
   // If not real stack overflow the stack guard was used to interrupt
   // execution for another purpose.
 
+  // If this is a direct call from JavaScript retry the RegExp forcing the call
+  // through the runtime system. Currently the direct call cannot handle a GC.
+  if (frame_entry<int>(re_frame, kDirectCall) == 1) {
+    return RETRY;
+  }
+
   // Prepare for possible GC.
   HandleScope handles;
   Handle<Code> code_handle(re_code);
diff --git a/src/ia32/regexp-macro-assembler-ia32.h b/src/ia32/regexp-macro-assembler-ia32.h
index 5ffd462..8e7a6a5 100644
--- a/src/ia32/regexp-macro-assembler-ia32.h
+++ b/src/ia32/regexp-macro-assembler-ia32.h
@@ -78,10 +78,7 @@
   // Checks whether the given offset from the current position is before
   // the end of the string.
   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
-  virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
-                                          Label* on_no_match);
+  virtual bool CheckSpecialCharacterClass(uc16 type, Label* on_no_match);
   virtual void Fail();
   virtual Handle<Object> GetCode(Handle<String> source);
   virtual void GoTo(Label* label);
@@ -128,6 +125,7 @@
   static const int kRegisterOutput = kInputEnd + kPointerSize;
   static const int kAtStart = kRegisterOutput + kPointerSize;
   static const int kStackHighEnd = kAtStart + kPointerSize;
+  static const int kDirectCall = kStackHighEnd + kPointerSize;
   // Below the frame pointer - local stack variables.
   // When adding local variables remember to push space for them in
   // the frame in GetCode.
diff --git a/src/ia32/simulator-ia32.h b/src/ia32/simulator-ia32.h
index ce7ed0e..3ebd2e6 100644
--- a/src/ia32/simulator-ia32.h
+++ b/src/ia32/simulator-ia32.h
@@ -52,9 +52,9 @@
 };
 
 // Call the generated regexp code directly. The entry function pointer should
-// expect seven int/pointer sized arguments and return an int.
-#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
-  entry(p0, p1, p2, p3, p4, p5, p6)
+// expect eight int/pointer sized arguments and return an int.
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6, p7) \
+  entry(p0, p1, p2, p3, p4, p5, p6, p7)
 
 #define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
   reinterpret_cast<TryCatch*>(try_catch_address)
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index 75e478b..2184230 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -236,7 +236,7 @@
   // Load length from the string and convert to a smi.
   __ bind(&load_length);
   __ mov(eax, FieldOperand(receiver, String::kLengthOffset));
-  __ shl(eax, kSmiTagSize);
+  __ SmiTag(eax);
   __ ret(0);
 
   // Check if the object is a JSValue wrapper.
@@ -1900,17 +1900,23 @@
   // depending on the this.x = ...; assignment in the function.
   for (int i = 0; i < shared->this_property_assignments_count(); i++) {
     if (shared->IsThisPropertyAssignmentArgument(i)) {
-      Label not_passed;
-      // Set the property to undefined.
-      __ mov(Operand(edx, i * kPointerSize), edi);
       // Check if the argument assigned to the property is actually passed.
+      // If argument is not passed the property is set to undefined,
+      // otherwise find it on the stack.
       int arg_number = shared->GetThisPropertyAssignmentArgument(i);
+      __ mov(ebx, edi);
       __ cmp(eax, arg_number);
-      __ j(below_equal, &not_passed);
-      // Argument passed - find it on the stack.
-      __ mov(ebx, Operand(ecx, arg_number * -kPointerSize));
+      if (CpuFeatures::IsSupported(CMOV)) {
+        CpuFeatures::Scope use_cmov(CMOV);
+        __ cmov(above, ebx, Operand(ecx, arg_number * -kPointerSize));
+      } else {
+        Label not_passed;
+        __ j(below_equal, &not_passed);
+        __ mov(ebx, Operand(ecx, arg_number * -kPointerSize));
+        __ bind(&not_passed);
+      }
+      // Store value in the property.
       __ mov(Operand(edx, i * kPointerSize), ebx);
-      __ bind(&not_passed);
     } else {
       // Set the property to the constant value.
       Handle<Object> constant(shared->GetThisPropertyAssignmentConstant(i));
diff --git a/src/ia32/virtual-frame-ia32.cc b/src/ia32/virtual-frame-ia32.cc
index ba64886..104d187 100644
--- a/src/ia32/virtual-frame-ia32.cc
+++ b/src/ia32/virtual-frame-ia32.cc
@@ -513,13 +513,33 @@
     Handle<Object> undefined = Factory::undefined_value();
     FrameElement initial_value =
         FrameElement::ConstantElement(undefined, FrameElement::SYNCED);
-    Result temp = cgen()->allocator()->Allocate();
-    ASSERT(temp.is_valid());
-    __ Set(temp.reg(), Immediate(undefined));
+    if (count == 1) {
+      __ push(Immediate(undefined));
+    } else if (count < kLocalVarBound) {
+      // For less locals the unrolled loop is more compact.
+      Result temp = cgen()->allocator()->Allocate();
+      ASSERT(temp.is_valid());
+      __ Set(temp.reg(), Immediate(undefined));
+      for (int i = 0; i < count; i++) {
+        __ push(temp.reg());
+      }
+    } else {
+      // For more locals a loop in generated code is more compact.
+      Label alloc_locals_loop;
+      Result cnt = cgen()->allocator()->Allocate();
+      Result tmp = cgen()->allocator()->Allocate();
+      ASSERT(cnt.is_valid());
+      ASSERT(tmp.is_valid());
+      __ mov(cnt.reg(), Immediate(count));
+      __ mov(tmp.reg(), Immediate(undefined));
+      __ bind(&alloc_locals_loop);
+      __ push(tmp.reg());
+      __ dec(cnt.reg());
+      __ j(not_zero, &alloc_locals_loop);
+    }
     for (int i = 0; i < count; i++) {
       elements_.Add(initial_value);
       stack_pointer_++;
-      __ push(temp.reg());
     }
   }
 }
diff --git a/src/ia32/virtual-frame-ia32.h b/src/ia32/virtual-frame-ia32.h
index 6c6b481..d6d55d1 100644
--- a/src/ia32/virtual-frame-ia32.h
+++ b/src/ia32/virtual-frame-ia32.h
@@ -199,6 +199,9 @@
   // shared return site.  Emits code for spills.
   void PrepareForReturn();
 
+  // Number of local variables after when we use a loop for allocating.
+  static const int kLocalVarBound = 10;
+
   // Allocate and initialize the frame-allocated locals.
   void AllocateStackSlots();
 
@@ -392,6 +395,8 @@
   // Pushing a result invalidates it (its contents become owned by the
   // frame).
   void Push(Result* result) {
+    // This assert will trigger if you try to push the same value twice.
+    ASSERT(result->is_valid());
     if (result->is_register()) {
       Push(result->reg());
     } else {
diff --git a/src/ic.cc b/src/ic.cc
index 2661a10..4edf6f1 100644
--- a/src/ic.cc
+++ b/src/ic.cc
@@ -874,7 +874,9 @@
 
   if (use_ic) {
     Code* stub = generic_stub();
-    if (object->IsJSObject()) {
+    if (object->IsString() && key->IsNumber()) {
+      stub = string_stub();
+    } else if (object->IsJSObject()) {
       Handle<JSObject> receiver = Handle<JSObject>::cast(object);
       if (receiver->HasExternalArrayElements()) {
         stub = external_array_stub(receiver->GetElementsKind());
diff --git a/src/ic.h b/src/ic.h
index f53c6dd..1dd7edf 100644
--- a/src/ic.h
+++ b/src/ic.h
@@ -280,6 +280,7 @@
   static void GenerateInitialize(MacroAssembler* masm);
   static void GeneratePreMonomorphic(MacroAssembler* masm);
   static void GenerateGeneric(MacroAssembler* masm);
+  static void GenerateString(MacroAssembler* masm);
 
   // Generators for external array types. See objects.h.
   // These are similar to the generic IC; they optimize the case of
@@ -313,6 +314,9 @@
   static Code* pre_monomorphic_stub() {
     return Builtins::builtin(Builtins::KeyedLoadIC_PreMonomorphic);
   }
+  static Code* string_stub() {
+    return Builtins::builtin(Builtins::KeyedLoadIC_String);
+  }
   static Code* external_array_stub(JSObject::ElementsKind elements_kind);
 
   static void Clear(Address address, Code* target);
diff --git a/src/jsregexp.cc b/src/jsregexp.cc
index 04d1944..8af472d 100644
--- a/src/jsregexp.cc
+++ b/src/jsregexp.cc
@@ -112,37 +112,6 @@
 // Generic RegExp methods. Dispatches to implementation specific methods.
 
 
-class OffsetsVector {
- public:
-  inline OffsetsVector(int num_registers)
-      : offsets_vector_length_(num_registers) {
-    if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
-      vector_ = NewArray<int>(offsets_vector_length_);
-    } else {
-      vector_ = static_offsets_vector_;
-    }
-  }
-  inline ~OffsetsVector() {
-    if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
-      DeleteArray(vector_);
-      vector_ = NULL;
-    }
-  }
-  inline int* vector() { return vector_; }
-  inline int length() { return offsets_vector_length_; }
-
- private:
-  int* vector_;
-  int offsets_vector_length_;
-  static const int kStaticOffsetsVectorSize = 50;
-  static int static_offsets_vector_[kStaticOffsetsVectorSize];
-};
-
-
-int OffsetsVector::static_offsets_vector_[
-    OffsetsVector::kStaticOffsetsVectorSize];
-
-
 Handle<Object> RegExpImpl::Compile(Handle<JSRegExp> re,
                                    Handle<String> pattern,
                                    Handle<String> flag_str) {
@@ -448,6 +417,14 @@
   ASSERT(array->length() >= number_of_capture_registers + kLastMatchOverhead);
   // The captures come in (start, end+1) pairs.
   for (int i = 0; i < number_of_capture_registers; i += 2) {
+    // Capture values are relative to start_offset only.
+    // Convert them to be relative to start of string.
+    if (captures_vector[i] >= 0) {
+      captures_vector[i] += previous_index;
+    }
+    if (captures_vector[i + 1] >= 0) {
+      captures_vector[i + 1] += previous_index;
+    }
     SetCapture(*array, i, captures_vector[i]);
     SetCapture(*array, i + 1, captures_vector[i + 1]);
   }
@@ -1431,14 +1408,6 @@
                           int cp_offset,
                           bool check_offset,
                           bool preloaded) {
-  if (cc->is_standard() &&
-      macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
-                                                  cp_offset,
-                                                  check_offset,
-                                                  on_failure)) {
-    return;
-  }
-
   ZoneList<CharacterRange>* ranges = cc->ranges();
   int max_char;
   if (ascii) {
@@ -1489,6 +1458,12 @@
     macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
   }
 
+  if (cc->is_standard() &&
+        macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
+                                                    on_failure)) {
+      return;
+  }
+
   for (int i = 0; i < last_valid_range; i++) {
     CharacterRange& range = ranges->at(i);
     Label next_range;
@@ -1626,8 +1601,8 @@
 }
 
 
-int NegativeLookaheadChoiceNode:: EatsAtLeast(int still_to_find,
-                                              int recursion_depth) {
+int NegativeLookaheadChoiceNode::EatsAtLeast(int still_to_find,
+                                             int recursion_depth) {
   if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
   // Alternative 0 is the negative lookahead, alternative 1 is what comes
   // afterwards.
@@ -2049,6 +2024,12 @@
                           Label* word,
                           Label* non_word,
                           bool fall_through_on_word) {
+  if (assembler->CheckSpecialCharacterClass(
+          fall_through_on_word ? 'w' : 'W',
+          fall_through_on_word ? non_word : word)) {
+    // Optimized implementation available.
+    return;
+  }
   assembler->CheckCharacterGT('z', non_word);
   assembler->CheckCharacterLT('0', non_word);
   assembler->CheckCharacterGT('a' - 1, word);
@@ -2085,17 +2066,60 @@
   assembler->LoadCurrentCharacter(new_trace.cp_offset() -1,
                                   new_trace.backtrack(),
                                   false);
-  // Newline means \n, \r, 0x2028 or 0x2029.
-  if (!compiler->ascii()) {
-    assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
+  if (!assembler->CheckSpecialCharacterClass('n',
+                                             new_trace.backtrack())) {
+    // Newline means \n, \r, 0x2028 or 0x2029.
+    if (!compiler->ascii()) {
+      assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
+    }
+    assembler->CheckCharacter('\n', &ok);
+    assembler->CheckNotCharacter('\r', new_trace.backtrack());
   }
-  assembler->CheckCharacter('\n', &ok);
-  assembler->CheckNotCharacter('\r', new_trace.backtrack());
   assembler->Bind(&ok);
   on_success->Emit(compiler, &new_trace);
 }
 
 
+// Emit the code to handle \b and \B (word-boundary or non-word-boundary)
+// when we know whether the next character must be a word character or not.
+static void EmitHalfBoundaryCheck(AssertionNode::AssertionNodeType type,
+                                  RegExpCompiler* compiler,
+                                  RegExpNode* on_success,
+                                  Trace* trace) {
+  RegExpMacroAssembler* assembler = compiler->macro_assembler();
+  Label done;
+
+  Trace new_trace(*trace);
+
+  bool expect_word_character = (type == AssertionNode::AFTER_WORD_CHARACTER);
+  Label* on_word = expect_word_character ? &done : new_trace.backtrack();
+  Label* on_non_word = expect_word_character ? new_trace.backtrack() : &done;
+
+  // Check whether previous character was a word character.
+  switch (trace->at_start()) {
+    case Trace::TRUE:
+      if (expect_word_character) {
+        assembler->GoTo(on_non_word);
+      }
+      break;
+    case Trace::UNKNOWN:
+      ASSERT_EQ(0, trace->cp_offset());
+      assembler->CheckAtStart(on_non_word);
+      // Fall through.
+    case Trace::FALSE:
+      int prev_char_offset = trace->cp_offset() - 1;
+      assembler->LoadCurrentCharacter(prev_char_offset, NULL, false, 1);
+      EmitWordCheck(assembler, on_word, on_non_word, expect_word_character);
+      // We may or may not have loaded the previous character.
+      new_trace.InvalidateCurrentCharacter();
+  }
+
+  assembler->Bind(&done);
+
+  on_success->Emit(compiler, &new_trace);
+}
+
+
 // Emit the code to handle \b and \B (word-boundary or non-word-boundary).
 static void EmitBoundaryCheck(AssertionNode::AssertionNodeType type,
                               RegExpCompiler* compiler,
@@ -2205,10 +2229,15 @@
     case AFTER_NEWLINE:
       EmitHat(compiler, on_success(), trace);
       return;
-    case AT_NON_BOUNDARY:
     case AT_BOUNDARY:
+    case AT_NON_BOUNDARY: {
       EmitBoundaryCheck(type_, compiler, on_success(), trace);
       return;
+    }
+    case AFTER_WORD_CHARACTER:
+    case AFTER_NONWORD_CHARACTER: {
+      EmitHalfBoundaryCheck(type_, compiler, on_success(), trace);
+    }
   }
   on_success()->Emit(compiler, trace);
 }
@@ -2791,7 +2820,7 @@
       // to generate probably can't use it.
       if (i != first_normal_choice) {
         alt_gen->expects_preload = false;
-        new_trace.set_characters_preloaded(0);
+        new_trace.InvalidateCurrentCharacter();
       }
       if (i < choice_count - 1) {
         new_trace.set_backtrack(&alt_gen->after);
@@ -3282,6 +3311,12 @@
     case AssertionNode::AFTER_NEWLINE:
       stream()->Add("label=\"(?<=\\n)\", shape=septagon");
       break;
+    case AssertionNode::AFTER_WORD_CHARACTER:
+      stream()->Add("label=\"(?<=\\w)\", shape=septagon");
+      break;
+    case AssertionNode::AFTER_NONWORD_CHARACTER:
+      stream()->Add("label=\"(?<=\\W)\", shape=septagon");
+      break;
   }
   stream()->Add("];\n");
   PrintAttributes(that);
@@ -3484,6 +3519,20 @@
     set_.set_standard_set_type('.');
     return true;
   }
+  if (CompareRanges(set_.ranges(),
+                    kLineTerminatorRanges,
+                    kLineTerminatorRangeCount)) {
+    set_.set_standard_set_type('n');
+    return true;
+  }
+  if (CompareRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
+    set_.set_standard_set_type('w');
+    return true;
+  }
+  if (CompareInverseRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
+    set_.set_standard_set_type('W');
+    return true;
+  }
   return false;
 }
 
@@ -4010,6 +4059,101 @@
 }
 
 
+bool CharacterRange::IsCanonical(ZoneList<CharacterRange>* ranges) {
+  ASSERT_NOT_NULL(ranges);
+  int n = ranges->length();
+  if (n <= 1) return true;
+  int max = ranges->at(0).to();
+  for (int i = 1; i < n; i++) {
+    CharacterRange next_range = ranges->at(i);
+    if (next_range.from() <= max + 1) return false;
+    max = next_range.to();
+  }
+  return true;
+}
+
+SetRelation CharacterRange::WordCharacterRelation(
+    ZoneList<CharacterRange>* range) {
+  ASSERT(IsCanonical(range));
+  int i = 0;  // Word character range index.
+  int j = 0;  // Argument range index.
+  ASSERT_NE(0, kWordRangeCount);
+  SetRelation result;
+  if (range->length() == 0) {
+    result.SetElementsInSecondSet();
+    return result;
+  }
+  CharacterRange argument_range = range->at(0);
+  CharacterRange word_range = CharacterRange(kWordRanges[0], kWordRanges[1]);
+  while (i < kWordRangeCount && j < range->length()) {
+    // Check the two ranges for the five cases:
+    // - no overlap.
+    // - partial overlap (there are elements in both ranges that isn't
+    //   in the other, and there are also elements that are in both).
+    // - argument range entirely inside word range.
+    // - word range entirely inside argument range.
+    // - ranges are completely equal.
+
+    // First check for no overlap. The earlier range is not in the other set.
+    if (argument_range.from() > word_range.to()) {
+      // Ranges are disjoint. The earlier word range contains elements that
+      // cannot be in the argument set.
+      result.SetElementsInSecondSet();
+    } else if (word_range.from() > argument_range.to()) {
+      // Ranges are disjoint. The earlier argument range contains elements that
+      // cannot be in the word set.
+      result.SetElementsInFirstSet();
+    } else if (word_range.from() <= argument_range.from() &&
+               word_range.to() >= argument_range.from()) {
+      result.SetElementsInBothSets();
+      // argument range completely inside word range.
+      if (word_range.from() < argument_range.from() ||
+          word_range.to() > argument_range.from()) {
+        result.SetElementsInSecondSet();
+      }
+    } else if (word_range.from() >= argument_range.from() &&
+               word_range.to() <= argument_range.from()) {
+      result.SetElementsInBothSets();
+      result.SetElementsInFirstSet();
+    } else {
+      // There is overlap, and neither is a subrange of the other
+      result.SetElementsInFirstSet();
+      result.SetElementsInSecondSet();
+      result.SetElementsInBothSets();
+    }
+    if (result.NonTrivialIntersection()) {
+      // The result is as (im)precise as we can possibly make it.
+      return result;
+    }
+    // Progress the range(s) with minimal to-character.
+    uc16 word_to = word_range.to();
+    uc16 argument_to = argument_range.to();
+    if (argument_to <= word_to) {
+      j++;
+      if (j < range->length()) {
+        argument_range = range->at(j);
+      }
+    }
+    if (word_to <= argument_to) {
+      i += 2;
+      if (i < kWordRangeCount) {
+        word_range = CharacterRange(kWordRanges[i], kWordRanges[i + 1]);
+      }
+    }
+  }
+  // Check if anything wasn't compared in the loop.
+  if (i < kWordRangeCount) {
+    // word range contains something not in argument range.
+    result.SetElementsInSecondSet();
+  } else if (j < range->length()) {
+    // Argument range contains something not in word range.
+    result.SetElementsInFirstSet();
+  }
+
+  return result;
+}
+
+
 static void AddUncanonicals(ZoneList<CharacterRange>* ranges,
                             int bottom,
                             int top) {
@@ -4119,6 +4263,287 @@
 }
 
 
+// Move a number of elements in a zonelist to another position
+// in the same list. Handles overlapping source and target areas.
+static void MoveRanges(ZoneList<CharacterRange>* list,
+                       int from,
+                       int to,
+                       int count) {
+  // Ranges are potentially overlapping.
+  if (from < to) {
+    for (int i = count - 1; i >= 0; i--) {
+      list->at(to + i) = list->at(from + i);
+    }
+  } else {
+    for (int i = 0; i < count; i++) {
+      list->at(to + i) = list->at(from + i);
+    }
+  }
+}
+
+
+static int InsertRangeInCanonicalList(ZoneList<CharacterRange>* list,
+                                      int count,
+                                      CharacterRange insert) {
+  // Inserts a range into list[0..count[, which must be sorted
+  // by from value and non-overlapping and non-adjacent, using at most
+  // list[0..count] for the result. Returns the number of resulting
+  // canonicalized ranges. Inserting a range may collapse existing ranges into
+  // fewer ranges, so the return value can be anything in the range 1..count+1.
+  uc16 from = insert.from();
+  uc16 to = insert.to();
+  int start_pos = 0;
+  int end_pos = count;
+  for (int i = count - 1; i >= 0; i--) {
+    CharacterRange current = list->at(i);
+    if (current.from() > to + 1) {
+      end_pos = i;
+    } else if (current.to() + 1 < from) {
+      start_pos = i + 1;
+      break;
+    }
+  }
+
+  // Inserted range overlaps, or is adjacent to, ranges at positions
+  // [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are
+  // not affected by the insertion.
+  // If start_pos == end_pos, the range must be inserted before start_pos.
+  // if start_pos < end_pos, the entire range from start_pos to end_pos
+  // must be merged with the insert range.
+
+  if (start_pos == end_pos) {
+    // Insert between existing ranges at position start_pos.
+    if (start_pos < count) {
+      MoveRanges(list, start_pos, start_pos + 1, count - start_pos);
+    }
+    list->at(start_pos) = insert;
+    return count + 1;
+  }
+  if (start_pos + 1 == end_pos) {
+    // Replace single existing range at position start_pos.
+    CharacterRange to_replace = list->at(start_pos);
+    int new_from = Min(to_replace.from(), from);
+    int new_to = Max(to_replace.to(), to);
+    list->at(start_pos) = CharacterRange(new_from, new_to);
+    return count;
+  }
+  // Replace a number of existing ranges from start_pos to end_pos - 1.
+  // Move the remaining ranges down.
+
+  int new_from = Min(list->at(start_pos).from(), from);
+  int new_to = Max(list->at(end_pos - 1).to(), to);
+  if (end_pos < count) {
+    MoveRanges(list, end_pos, start_pos + 1, count - end_pos);
+  }
+  list->at(start_pos) = CharacterRange(new_from, new_to);
+  return count - (end_pos - start_pos) + 1;
+}
+
+
+void CharacterSet::Canonicalize() {
+  // Special/default classes are always considered canonical. The result
+  // of calling ranges() will be sorted.
+  if (ranges_ == NULL) return;
+  CharacterRange::Canonicalize(ranges_);
+}
+
+
+void CharacterRange::Canonicalize(ZoneList<CharacterRange>* character_ranges) {
+  if (character_ranges->length() <= 1) return;
+  // Check whether ranges are already canonical (increasing, non-overlapping,
+  // non-adjacent).
+  int n = character_ranges->length();
+  int max = character_ranges->at(0).to();
+  int i = 1;
+  while (i < n) {
+    CharacterRange current = character_ranges->at(i);
+    if (current.from() <= max + 1) {
+      break;
+    }
+    max = current.to();
+    i++;
+  }
+  // Canonical until the i'th range. If that's all of them, we are done.
+  if (i == n) return;
+
+  // The ranges at index i and forward are not canonicalized. Make them so by
+  // doing the equivalent of insertion sort (inserting each into the previous
+  // list, in order).
+  // Notice that inserting a range can reduce the number of ranges in the
+  // result due to combining of adjacent and overlapping ranges.
+  int read = i;  // Range to insert.
+  int num_canonical = i;  // Length of canonicalized part of list.
+  do {
+    num_canonical = InsertRangeInCanonicalList(character_ranges,
+                                               num_canonical,
+                                               character_ranges->at(read));
+    read++;
+  } while (read < n);
+  character_ranges->Rewind(num_canonical);
+
+  ASSERT(CharacterRange::IsCanonical(character_ranges));
+}
+
+
+// Utility function for CharacterRange::Merge. Adds a range at the end of
+// a canonicalized range list, if necessary merging the range with the last
+// range of the list.
+static void AddRangeToSet(ZoneList<CharacterRange>* set, CharacterRange range) {
+  if (set == NULL) return;
+  ASSERT(set->length() == 0 || set->at(set->length() - 1).to() < range.from());
+  int n = set->length();
+  if (n > 0) {
+    CharacterRange lastRange = set->at(n - 1);
+    if (lastRange.to() == range.from() - 1) {
+      set->at(n - 1) = CharacterRange(lastRange.from(), range.to());
+      return;
+    }
+  }
+  set->Add(range);
+}
+
+
+static void AddRangeToSelectedSet(int selector,
+                                  ZoneList<CharacterRange>* first_set,
+                                  ZoneList<CharacterRange>* second_set,
+                                  ZoneList<CharacterRange>* intersection_set,
+                                  CharacterRange range) {
+  switch (selector) {
+    case kInsideFirst:
+      AddRangeToSet(first_set, range);
+      break;
+    case kInsideSecond:
+      AddRangeToSet(second_set, range);
+      break;
+    case kInsideBoth:
+      AddRangeToSet(intersection_set, range);
+      break;
+  }
+}
+
+
+
+void CharacterRange::Merge(ZoneList<CharacterRange>* first_set,
+                           ZoneList<CharacterRange>* second_set,
+                           ZoneList<CharacterRange>* first_set_only_out,
+                           ZoneList<CharacterRange>* second_set_only_out,
+                           ZoneList<CharacterRange>* both_sets_out) {
+  // Inputs are canonicalized.
+  ASSERT(CharacterRange::IsCanonical(first_set));
+  ASSERT(CharacterRange::IsCanonical(second_set));
+  // Outputs are empty, if applicable.
+  ASSERT(first_set_only_out == NULL || first_set_only_out->length() == 0);
+  ASSERT(second_set_only_out == NULL || second_set_only_out->length() == 0);
+  ASSERT(both_sets_out == NULL || both_sets_out->length() == 0);
+
+  // Merge sets by iterating through the lists in order of lowest "from" value,
+  // and putting intervals into one of three sets.
+
+  if (first_set->length() == 0) {
+    second_set_only_out->AddAll(*second_set);
+    return;
+  }
+  if (second_set->length() == 0) {
+    first_set_only_out->AddAll(*first_set);
+    return;
+  }
+  // Indices into input lists.
+  int i1 = 0;
+  int i2 = 0;
+  // Cache length of input lists.
+  int n1 = first_set->length();
+  int n2 = second_set->length();
+  // Current range. May be invalid if state is kInsideNone.
+  int from = 0;
+  int to = -1;
+  // Where current range comes from.
+  int state = kInsideNone;
+
+  while (i1 < n1 || i2 < n2) {
+    CharacterRange next_range;
+    int range_source;
+    if (i2 == n2 || first_set->at(i1).from() < second_set->at(i2).from()) {
+      next_range = first_set->at(i1++);
+      range_source = kInsideFirst;
+    } else {
+      next_range = second_set->at(i2++);
+      range_source = kInsideSecond;
+    }
+    if (to < next_range.from()) {
+      // Ranges disjoint: |current|  |next|
+      AddRangeToSelectedSet(state,
+                            first_set_only_out,
+                            second_set_only_out,
+                            both_sets_out,
+                            CharacterRange(from, to));
+      from = next_range.from();
+      to = next_range.to();
+      state = range_source;
+    } else {
+      if (from < next_range.from()) {
+        AddRangeToSelectedSet(state,
+                              first_set_only_out,
+                              second_set_only_out,
+                              both_sets_out,
+                              CharacterRange(from, next_range.from()-1));
+      }
+      if (to < next_range.to()) {
+        // Ranges overlap:  |current|
+        //                       |next|
+        AddRangeToSelectedSet(state | range_source,
+                              first_set_only_out,
+                              second_set_only_out,
+                              both_sets_out,
+                              CharacterRange(next_range.from(), to));
+        from = to + 1;
+        to = next_range.to();
+        state = range_source;
+      } else {
+        // Range included:    |current| , possibly ending at same character.
+        //                      |next|
+        AddRangeToSelectedSet(
+            state | range_source,
+            first_set_only_out,
+            second_set_only_out,
+            both_sets_out,
+            CharacterRange(next_range.from(), next_range.to()));
+        from = next_range.to() + 1;
+        // If ranges end at same character, both ranges are consumed completely.
+        if (next_range.to() == to) state = kInsideNone;
+      }
+    }
+  }
+  AddRangeToSelectedSet(state,
+                        first_set_only_out,
+                        second_set_only_out,
+                        both_sets_out,
+                        CharacterRange(from, to));
+}
+
+
+void CharacterRange::Negate(ZoneList<CharacterRange>* ranges,
+                            ZoneList<CharacterRange>* negated_ranges) {
+  ASSERT(CharacterRange::IsCanonical(ranges));
+  ASSERT_EQ(0, negated_ranges->length());
+  int range_count = ranges->length();
+  uc16 from = 0;
+  int i = 0;
+  if (range_count > 0 && ranges->at(0).from() == 0) {
+    from = ranges->at(0).to();
+    i = 1;
+  }
+  while (i < range_count) {
+    CharacterRange range = ranges->at(i);
+    negated_ranges->Add(CharacterRange(from + 1, range.from() - 1));
+    from = range.to();
+    i++;
+  }
+  if (from < String::kMaxUC16CharCode) {
+    negated_ranges->Add(CharacterRange(from + 1, String::kMaxUC16CharCode));
+  }
+}
+
+
 
 // -------------------------------------------------------------------
 // Interest propagation
@@ -4410,9 +4835,203 @@
 
 void Analysis::VisitAssertion(AssertionNode* that) {
   EnsureAnalyzed(that->on_success());
+  AssertionNode::AssertionNodeType type = that->type();
+  if (type == AssertionNode::AT_BOUNDARY ||
+      type == AssertionNode::AT_NON_BOUNDARY) {
+    // Check if the following character is known to be a word character
+    // or known to not be a word character.
+    ZoneList<CharacterRange>* following_chars = that->FirstCharacterSet();
+
+    CharacterRange::Canonicalize(following_chars);
+
+    SetRelation word_relation =
+        CharacterRange::WordCharacterRelation(following_chars);
+    if (word_relation.ContainedIn()) {
+      // Following character is definitely a word character.
+      type = (type == AssertionNode::AT_BOUNDARY) ?
+                  AssertionNode::AFTER_NONWORD_CHARACTER :
+                  AssertionNode::AFTER_WORD_CHARACTER;
+      that->set_type(type);
+    } else if (word_relation.Disjoint()) {
+      // Following character is definitely *not* a word character.
+      type = (type == AssertionNode::AT_BOUNDARY) ?
+                  AssertionNode::AFTER_WORD_CHARACTER :
+                  AssertionNode::AFTER_NONWORD_CHARACTER;
+      that->set_type(type);
+    }
+  }
 }
 
 
+ZoneList<CharacterRange>* RegExpNode::FirstCharacterSet() {
+  if (first_character_set_ == NULL) {
+    if (ComputeFirstCharacterSet(kFirstCharBudget) < 0) {
+      // If we can't find an exact solution within the budget, we
+      // set the value to the set of every character, i.e., all characters
+      // are possible.
+      ZoneList<CharacterRange>* all_set = new ZoneList<CharacterRange>(1);
+      all_set->Add(CharacterRange::Everything());
+      first_character_set_ = all_set;
+    }
+  }
+  return first_character_set_;
+}
+
+
+int RegExpNode::ComputeFirstCharacterSet(int budget) {
+  // Default behavior is to not be able to determine the first character.
+  return kComputeFirstCharacterSetFail;
+}
+
+
+int LoopChoiceNode::ComputeFirstCharacterSet(int budget) {
+  budget--;
+  if (budget >= 0) {
+    // Find loop min-iteration. It's the value of the guarded choice node
+    // with a GEQ guard, if any.
+    int min_repetition = 0;
+
+    for (int i = 0; i <= 1; i++) {
+      GuardedAlternative alternative = alternatives()->at(i);
+      ZoneList<Guard*>* guards = alternative.guards();
+      if (guards != NULL && guards->length() > 0) {
+        Guard* guard = guards->at(0);
+        if (guard->op() == Guard::GEQ) {
+          min_repetition = guard->value();
+          break;
+        }
+      }
+    }
+
+    budget = loop_node()->ComputeFirstCharacterSet(budget);
+    if (budget >= 0) {
+      ZoneList<CharacterRange>* character_set =
+          loop_node()->first_character_set();
+      if (body_can_be_zero_length() || min_repetition == 0) {
+        budget = continue_node()->ComputeFirstCharacterSet(budget);
+        if (budget < 0) return budget;
+        ZoneList<CharacterRange>* body_set =
+            continue_node()->first_character_set();
+        ZoneList<CharacterRange>* union_set =
+          new ZoneList<CharacterRange>(Max(character_set->length(),
+                                           body_set->length()));
+        CharacterRange::Merge(character_set,
+                              body_set,
+                              union_set,
+                              union_set,
+                              union_set);
+        character_set = union_set;
+      }
+      set_first_character_set(character_set);
+    }
+  }
+  return budget;
+}
+
+
+int NegativeLookaheadChoiceNode::ComputeFirstCharacterSet(int budget) {
+  budget--;
+  if (budget >= 0) {
+    GuardedAlternative successor = this->alternatives()->at(1);
+    RegExpNode* successor_node = successor.node();
+    budget = successor_node->ComputeFirstCharacterSet(budget);
+    if (budget >= 0) {
+      set_first_character_set(successor_node->first_character_set());
+    }
+  }
+  return budget;
+}
+
+
+// The first character set of an EndNode is unknowable. Just use the
+// default implementation that fails and returns all characters as possible.
+
+
+int AssertionNode::ComputeFirstCharacterSet(int budget) {
+  budget -= 1;
+  if (budget >= 0) {
+    switch (type_) {
+      case AT_END: {
+        set_first_character_set(new ZoneList<CharacterRange>(0));
+        break;
+      }
+      case AT_START:
+      case AT_BOUNDARY:
+      case AT_NON_BOUNDARY:
+      case AFTER_NEWLINE:
+      case AFTER_NONWORD_CHARACTER:
+      case AFTER_WORD_CHARACTER: {
+        ASSERT_NOT_NULL(on_success());
+        budget = on_success()->ComputeFirstCharacterSet(budget);
+        set_first_character_set(on_success()->first_character_set());
+        break;
+      }
+    }
+  }
+  return budget;
+}
+
+
+int ActionNode::ComputeFirstCharacterSet(int budget) {
+  if (type_ == POSITIVE_SUBMATCH_SUCCESS) return kComputeFirstCharacterSetFail;
+  budget--;
+  if (budget >= 0) {
+    ASSERT_NOT_NULL(on_success());
+    budget = on_success()->ComputeFirstCharacterSet(budget);
+    if (budget >= 0) {
+      set_first_character_set(on_success()->first_character_set());
+    }
+  }
+  return budget;
+}
+
+
+int BackReferenceNode::ComputeFirstCharacterSet(int budget) {
+  // We don't know anything about the first character of a backreference
+  // at this point.
+  return kComputeFirstCharacterSetFail;
+}
+
+
+int TextNode::ComputeFirstCharacterSet(int budget) {
+  budget--;
+  if (budget >= 0) {
+    ASSERT_NE(0, elements()->length());
+    TextElement text = elements()->at(0);
+    if (text.type == TextElement::ATOM) {
+      RegExpAtom* atom = text.data.u_atom;
+      ASSERT_NE(0, atom->length());
+      uc16 first_char = atom->data()[0];
+      ZoneList<CharacterRange>* range = new ZoneList<CharacterRange>(1);
+      range->Add(CharacterRange(first_char, first_char));
+      set_first_character_set(range);
+    } else {
+      ASSERT(text.type == TextElement::CHAR_CLASS);
+      RegExpCharacterClass* char_class = text.data.u_char_class;
+      if (char_class->is_negated()) {
+        ZoneList<CharacterRange>* ranges = char_class->ranges();
+        int length = ranges->length();
+        int new_length = length + 1;
+        if (length > 0) {
+          if (ranges->at(0).from() == 0) new_length--;
+          if (ranges->at(length - 1).to() == String::kMaxUC16CharCode) {
+            new_length--;
+          }
+        }
+        ZoneList<CharacterRange>* negated_ranges =
+            new ZoneList<CharacterRange>(new_length);
+        CharacterRange::Negate(ranges, negated_ranges);
+        set_first_character_set(negated_ranges);
+      } else {
+        set_first_character_set(char_class->ranges());
+      }
+    }
+  }
+  return budget;
+}
+
+
+
 // -------------------------------------------------------------------
 // Dispatch table construction
 
@@ -4471,7 +5090,6 @@
 }
 
 
-
 static int CompareRangeByFrom(const CharacterRange* a,
                               const CharacterRange* b) {
   return Compare<uc16>(a->from(), b->from());
@@ -4606,4 +5224,8 @@
                            pattern);
 }
 
+
+int OffsetsVector::static_offsets_vector_[
+    OffsetsVector::kStaticOffsetsVectorSize];
+
 }}  // namespace v8::internal
diff --git a/src/jsregexp.h b/src/jsregexp.h
index b681119..b99a89e 100644
--- a/src/jsregexp.h
+++ b/src/jsregexp.h
@@ -75,13 +75,6 @@
                              int index,
                              Handle<JSArray> lastMatchInfo);
 
-  // Call RegExp.prototyp.exec(string) in a loop.
-  // Used by String.prototype.match and String.prototype.replace.
-  // This function calls the garbage collector if necessary.
-  static Handle<Object> ExecGlobal(Handle<JSRegExp> regexp,
-                                   Handle<String> subject,
-                                   Handle<JSArray> lastMatchInfo);
-
   // Prepares a JSRegExp object with Irregexp-specific data.
   static void IrregexpPrepare(Handle<JSRegExp> re,
                               Handle<String> pattern,
@@ -108,13 +101,23 @@
                                      int index,
                                      Handle<JSArray> lastMatchInfo);
 
-  // Offsets in the lastMatchInfo array.
+  // Array index in the lastMatchInfo array.
   static const int kLastCaptureCount = 0;
   static const int kLastSubject = 1;
   static const int kLastInput = 2;
   static const int kFirstCapture = 3;
   static const int kLastMatchOverhead = 3;
 
+  // Direct offset into the lastMatchInfo array.
+  static const int kLastCaptureCountOffset =
+      FixedArray::kHeaderSize + kLastCaptureCount * kPointerSize;
+  static const int kLastSubjectOffset =
+      FixedArray::kHeaderSize + kLastSubject * kPointerSize;
+  static const int kLastInputOffset =
+      FixedArray::kHeaderSize + kLastInput * kPointerSize;
+  static const int kFirstCaptureOffset =
+      FixedArray::kHeaderSize + kFirstCapture * kPointerSize;
+
   // Used to access the lastMatchInfo array.
   static int GetCapture(FixedArray* array, int index) {
     return Smi::cast(array->get(index + kFirstCapture))->value();
@@ -174,6 +177,57 @@
 };
 
 
+// Represents the location of one element relative to the intersection of
+// two sets. Corresponds to the four areas of a Venn diagram.
+enum ElementInSetsRelation {
+  kInsideNone = 0,
+  kInsideFirst = 1,
+  kInsideSecond = 2,
+  kInsideBoth = 3
+};
+
+
+// Represents the relation of two sets.
+// Sets can be either disjoint, partially or fully overlapping, or equal.
+class SetRelation BASE_EMBEDDED {
+ public:
+  // Relation is represented by a bit saying whether there are elements in
+  // one set that is not in the other, and a bit saying that there are elements
+  // that are in both sets.
+
+  // Location of an element. Corresponds to the internal areas of
+  // a Venn diagram.
+  enum {
+    kInFirst = 1 << kInsideFirst,
+    kInSecond = 1 << kInsideSecond,
+    kInBoth = 1 << kInsideBoth
+  };
+  SetRelation() : bits_(0) {}
+  ~SetRelation() {}
+  // Add the existence of objects in a particular
+  void SetElementsInFirstSet() { bits_ |= kInFirst; }
+  void SetElementsInSecondSet() { bits_ |= kInSecond; }
+  void SetElementsInBothSets() { bits_ |= kInBoth; }
+  // Check the currently known relation of the sets (common functions only,
+  // for other combinations, use value() to get the bits and check them
+  // manually).
+  // Sets are completely disjoint.
+  bool Disjoint() { return (bits_ & kInBoth) == 0; }
+  // Sets are equal.
+  bool Equals() { return (bits_ & (kInFirst | kInSecond)) == 0; }
+  // First set contains second.
+  bool Contains() { return (bits_ & kInSecond) == 0; }
+  // Second set contains first.
+  bool ContainedIn() { return (bits_ & kInFirst) == 0; }
+  bool NonTrivialIntersection() {
+    return (bits_ == (kInFirst | kInSecond | kInBoth));
+  }
+  int value() { return bits_; }
+ private:
+  int bits_;
+};
+
+
 class CharacterRange {
  public:
   CharacterRange() : from_(0), to_(0) { }
@@ -205,7 +259,39 @@
                     Vector<const uc16> overlay,
                     ZoneList<CharacterRange>** included,
                     ZoneList<CharacterRange>** excluded);
-
+  // Whether a range list is in canonical form: Ranges ordered by from value,
+  // and ranges non-overlapping and non-adjacent.
+  static bool IsCanonical(ZoneList<CharacterRange>* ranges);
+  // Convert range list to canonical form. The characters covered by the ranges
+  // will still be the same, but no character is in more than one range, and
+  // adjacent ranges are merged. The resulting list may be shorter than the
+  // original, but cannot be longer.
+  static void Canonicalize(ZoneList<CharacterRange>* ranges);
+  // Check how the set of characters defined by a CharacterRange list relates
+  // to the set of word characters. List must be in canonical form.
+  static SetRelation WordCharacterRelation(ZoneList<CharacterRange>* ranges);
+  // Takes two character range lists (representing character sets) in canonical
+  // form and merges them.
+  // The characters that are only covered by the first set are added to
+  // first_set_only_out. the characters that are only in the second set are
+  // added to second_set_only_out, and the characters that are in both are
+  // added to both_sets_out.
+  // The pointers to first_set_only_out, second_set_only_out and both_sets_out
+  // should be to empty lists, but they need not be distinct, and may be NULL.
+  // If NULL, the characters are dropped, and if two arguments are the same
+  // pointer, the result is the union of the two sets that would be created
+  // if the pointers had been distinct.
+  // This way, the Merge function can compute all the usual set operations:
+  // union (all three out-sets are equal), intersection (only both_sets_out is
+  // non-NULL), and set difference (only first_set is non-NULL).
+  static void Merge(ZoneList<CharacterRange>* first_set,
+                    ZoneList<CharacterRange>* second_set,
+                    ZoneList<CharacterRange>* first_set_only_out,
+                    ZoneList<CharacterRange>* second_set_only_out,
+                    ZoneList<CharacterRange>* both_sets_out);
+  // Negate the contents of a character range in canonical form.
+  static void Negate(ZoneList<CharacterRange>* src,
+                     ZoneList<CharacterRange>* dst);
   static const int kRangeCanonicalizeMax = 0x346;
   static const int kStartMarker = (1 << 24);
   static const int kPayloadMask = (1 << 24) - 1;
@@ -479,7 +565,7 @@
 
 class RegExpNode: public ZoneObject {
  public:
-  RegExpNode() : trace_count_(0) { }
+  RegExpNode() : first_character_set_(NULL), trace_count_(0) { }
   virtual ~RegExpNode();
   virtual void Accept(NodeVisitor* visitor) = 0;
   // Generates a goto to this node or actually generates the code at this point.
@@ -530,8 +616,29 @@
   SiblingList* siblings() { return &siblings_; }
   void set_siblings(SiblingList* other) { siblings_ = *other; }
 
+  // Return the set of possible next characters recognized by the regexp
+  // (or a safe subset, potentially the set of all characters).
+  ZoneList<CharacterRange>* FirstCharacterSet();
+
+  // Compute (if possible within the budget of traversed nodes) the
+  // possible first characters of the input matched by this node and
+  // its continuation. Returns the remaining budget after the computation.
+  // If the budget is spent, the result is negative, and the cached
+  // first_character_set_ value isn't set.
+  virtual int ComputeFirstCharacterSet(int budget);
+
+  // Get and set the cached first character set value.
+  ZoneList<CharacterRange>* first_character_set() {
+    return first_character_set_;
+  }
+  void set_first_character_set(ZoneList<CharacterRange>* character_set) {
+    first_character_set_ = character_set;
+  }
+
  protected:
   enum LimitResult { DONE, CONTINUE };
+  static const int kComputeFirstCharacterSetFail = -1;
+
   LimitResult LimitVersions(RegExpCompiler* compiler, Trace* trace);
 
   // Returns a sibling of this node whose interests and assumptions
@@ -552,9 +659,11 @@
   virtual RegExpNode* Clone() = 0;
 
  private:
+  static const int kFirstCharBudget = 10;
   Label label_;
   NodeInfo info_;
   SiblingList siblings_;
+  ZoneList<CharacterRange>* first_character_set_;
   // This variable keeps track of how many times code has been generated for
   // this node (in different traces).  We don't keep track of where the
   // generated code is located unless the code is generated at the start of
@@ -645,7 +754,7 @@
   // TODO(erikcorry): We should allow some action nodes in greedy loops.
   virtual int GreedyLoopTextLength() { return kNodeIsTooComplexForGreedyLoops; }
   virtual ActionNode* Clone() { return new ActionNode(*this); }
-
+  virtual int ComputeFirstCharacterSet(int budget);
  private:
   union {
     struct {
@@ -711,7 +820,7 @@
     return result;
   }
   void CalculateOffsets();
-
+  virtual int ComputeFirstCharacterSet(int budget);
  private:
   enum TextEmitPassType {
     NON_ASCII_MATCH,             // Check for characters that can't match.
@@ -741,7 +850,12 @@
     AT_START,
     AT_BOUNDARY,
     AT_NON_BOUNDARY,
-    AFTER_NEWLINE
+    AFTER_NEWLINE,
+    // Types not directly expressible in regexp syntax.
+    // Used for modifying a boundary node if its following character is
+    // known to be word and/or non-word.
+    AFTER_NONWORD_CHARACTER,
+    AFTER_WORD_CHARACTER
   };
   static AssertionNode* AtEnd(RegExpNode* on_success) {
     return new AssertionNode(AT_END, on_success);
@@ -765,8 +879,10 @@
                                     RegExpCompiler* compiler,
                                     int filled_in,
                                     bool not_at_start);
+  virtual int ComputeFirstCharacterSet(int budget);
   virtual AssertionNode* Clone() { return new AssertionNode(*this); }
   AssertionNodeType type() { return type_; }
+  void set_type(AssertionNodeType type) { type_ = type; }
  private:
   AssertionNode(AssertionNodeType t, RegExpNode* on_success)
       : SeqRegExpNode(on_success), type_(t) { }
@@ -794,7 +910,7 @@
     return;
   }
   virtual BackReferenceNode* Clone() { return new BackReferenceNode(*this); }
-
+  virtual int ComputeFirstCharacterSet(int budget);
  private:
   int start_reg_;
   int end_reg_;
@@ -816,7 +932,6 @@
     UNREACHABLE();
   }
   virtual EndNode* Clone() { return new EndNode(*this); }
-
  private:
   Action action_;
 };
@@ -950,6 +1065,7 @@
   // characters, but on a negative lookahead the negative branch did not take
   // part in that calculation (EatsAtLeast) so the assumptions don't hold.
   virtual bool try_to_emit_quick_check_for_alternative(int i) { return i != 0; }
+  virtual int ComputeFirstCharacterSet(int budget);
 };
 
 
@@ -968,6 +1084,7 @@
                                     RegExpCompiler* compiler,
                                     int characters_filled_in,
                                     bool not_at_start);
+  virtual int ComputeFirstCharacterSet(int budget);
   virtual LoopChoiceNode* Clone() { return new LoopChoiceNode(*this); }
   RegExpNode* loop_node() { return loop_node_; }
   RegExpNode* continue_node() { return continue_node_; }
@@ -1123,7 +1240,7 @@
   void set_backtrack(Label* backtrack) { backtrack_ = backtrack; }
   void set_stop_node(RegExpNode* node) { stop_node_ = node; }
   void set_loop_label(Label* label) { loop_label_ = label; }
-  void set_characters_preloaded(int cpre) { characters_preloaded_ = cpre; }
+  void set_characters_preloaded(int count) { characters_preloaded_ = count; }
   void set_bound_checked_up_to(int to) { bound_checked_up_to_ = to; }
   void set_flush_budget(int to) { flush_budget_ = to; }
   void set_quick_check_performed(QuickCheckDetails* d) {
@@ -1283,6 +1400,40 @@
 };
 
 
+class OffsetsVector {
+ public:
+  inline OffsetsVector(int num_registers)
+      : offsets_vector_length_(num_registers) {
+    if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
+      vector_ = NewArray<int>(offsets_vector_length_);
+    } else {
+      vector_ = static_offsets_vector_;
+    }
+  }
+  inline ~OffsetsVector() {
+    if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
+      DeleteArray(vector_);
+      vector_ = NULL;
+    }
+  }
+  inline int* vector() { return vector_; }
+  inline int length() { return offsets_vector_length_; }
+
+  static const int kStaticOffsetsVectorSize = 50;
+
+ private:
+  static Address static_offsets_vector_address() {
+    return reinterpret_cast<Address>(&static_offsets_vector_);
+  }
+
+  int* vector_;
+  int offsets_vector_length_;
+  static int static_offsets_vector_[kStaticOffsetsVectorSize];
+
+  friend class ExternalReference;
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_JSREGEXP_H_
diff --git a/src/jump-target.h b/src/jump-target.h
index 0933ee7..dd291c6 100644
--- a/src/jump-target.h
+++ b/src/jump-target.h
@@ -112,7 +112,8 @@
 
   // Emit a conditional branch to the target.  There must be a current
   // frame at the branch.  The current frame will fall through to the
-  // code after the branch.
+  // code after the branch.  The arg is a result that is live both at
+  // the target and the fall-through.
   virtual void Branch(Condition cc, Hint hint = no_hint);
   virtual void Branch(Condition cc, Result* arg, Hint hint = no_hint);
 
diff --git a/src/macros.py b/src/macros.py
index 5b06099..1e436a0 100644
--- a/src/macros.py
+++ b/src/macros.py
@@ -92,12 +92,13 @@
 macro IS_SCRIPT(arg)            = (%_ClassOf(arg) === 'Script');
 macro IS_ARGUMENTS(arg)         = (%_ClassOf(arg) === 'Arguments');
 macro IS_GLOBAL(arg)            = (%_ClassOf(arg) === 'global');
-macro FLOOR(arg)                = %Math_floor(arg);
+macro FLOOR(arg)                = $floor(arg);
 
 # Inline macros. Use %IS_VAR to make sure arg is evaluated only once.
 macro NUMBER_IS_NAN(arg) = (!%_IsSmi(%IS_VAR(arg)) && !(arg == arg));
 macro TO_INTEGER(arg)    = (%_IsSmi(%IS_VAR(arg)) ? arg : ToInteger(arg));
-macro TO_INT32(arg)      = (%_IsSmi(%IS_VAR(arg)) ? arg : ToInt32(arg));
+macro TO_INT32(arg)      = (%_IsSmi(%IS_VAR(arg)) ? arg : (arg >> 0));
+macro TO_UINT32(arg)     = (arg >>> 0);
 
 # Macros implemented in Python.
 python macro CHAR_CODE(str) = ord(str[1]);
@@ -117,6 +118,14 @@
 # Gets the value of a Date object. If arg is not a Date object
 # a type error is thrown.
 macro DATE_VALUE(arg) = (%_ClassOf(arg) === 'Date' ? %_ValueOf(arg) : ThrowDateTypeError());
+macro DAY(time) = ($floor(time / 86400000));
+macro MONTH_FROM_TIME(time) = (FromJulianDay(($floor(time / 86400000)) + 2440588).month);
+macro DATE_FROM_TIME(time) = (FromJulianDay(($floor(time / 86400000)) + 2440588).date);
+macro YEAR_FROM_TIME(time) = (FromJulianDay(($floor(time / 86400000)) + 2440588).year);
+macro HOUR_FROM_TIME(time) = (Modulo($floor(time / 3600000), 24));
+macro MIN_FROM_TIME(time) = (Modulo($floor(time / 60000), 60));
+macro SEC_FROM_TIME(time) = (Modulo($floor(time / 1000), 60));
+macro MS_FROM_TIME(time) = (Modulo(time, 1000));
 
 # Last input and last subject of regexp matches.
 macro LAST_SUBJECT(array) = ((array)[1]);
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 7a53537..e284b42 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -116,6 +116,8 @@
   compact_on_next_gc_ = false;
 
   if (FLAG_never_compact) compacting_collection_ = false;
+  if (!Heap::map_space()->MapPointersEncodable())
+      compacting_collection_ = false;
   if (FLAG_collect_maps) CreateBackPointers();
 
 #ifdef DEBUG
@@ -789,7 +791,7 @@
   // back pointers, reversing them all at once.  This allows us to find
   // those maps with map transitions that need to be nulled, and only
   // scan the descriptor arrays of those maps, not all maps.
-  // All of these actions are carried out only on maps of JSObects
+  // All of these actions are carried out only on maps of JSObjects
   // and related subtypes.
   while (map_iterator.has_next()) {
     Map* map = reinterpret_cast<Map*>(map_iterator.next());
@@ -1166,7 +1168,7 @@
 
 void MarkCompactCollector::DeallocateMapBlock(Address start,
                                               int size_in_bytes) {
-  // Objects in map space are frequently assumed to have size Map::kSize and a
+  // Objects in map space are assumed to have size Map::kSize and a
   // valid map in their first word.  Thus, we break the free block up into
   // chunks and free them separately.
   ASSERT(size_in_bytes % Map::kSize == 0);
@@ -1240,6 +1242,225 @@
 }
 
 
+class MapIterator : public HeapObjectIterator {
+ public:
+  MapIterator() : HeapObjectIterator(Heap::map_space(), &SizeCallback) { }
+
+  explicit MapIterator(Address start)
+      : HeapObjectIterator(Heap::map_space(), start, &SizeCallback) { }
+
+ private:
+  static int SizeCallback(HeapObject* unused) {
+    USE(unused);
+    return Map::kSize;
+  }
+};
+
+
+class MapCompact {
+ public:
+  explicit MapCompact(int live_maps)
+    : live_maps_(live_maps),
+      to_evacuate_start_(Heap::map_space()->TopAfterCompaction(live_maps)),
+      map_to_evacuate_it_(to_evacuate_start_),
+      first_map_to_evacuate_(
+          reinterpret_cast<Map*>(HeapObject::FromAddress(to_evacuate_start_))) {
+  }
+
+  void CompactMaps() {
+    // As we know the number of maps to evacuate beforehand,
+    // we stop then there is no more vacant maps.
+    for (Map* next_vacant_map = NextVacantMap();
+         next_vacant_map;
+         next_vacant_map = NextVacantMap()) {
+      EvacuateMap(next_vacant_map, NextMapToEvacuate());
+    }
+
+#ifdef DEBUG
+    CheckNoMapsToEvacuate();
+#endif
+  }
+
+  void UpdateMapPointersInRoots() {
+    Heap::IterateRoots(&map_updating_visitor_, VISIT_ONLY_STRONG);
+    GlobalHandles::IterateWeakRoots(&map_updating_visitor_);
+  }
+
+  void FinishMapSpace() {
+    // Iterate through to space and finish move.
+    MapIterator it;
+    HeapObject* o = it.next();
+    for (; o != first_map_to_evacuate_; o = it.next()) {
+      Map* map = reinterpret_cast<Map*>(o);
+      ASSERT(!map->IsMarked());
+      ASSERT(!map->IsOverflowed());
+      ASSERT(map->IsMap());
+      Heap::UpdateRSet(map);
+    }
+  }
+
+  void UpdateMapPointersInPagedSpace(PagedSpace* space) {
+    ASSERT(space != Heap::map_space());
+
+    PageIterator it(space, PageIterator::PAGES_IN_USE);
+    while (it.has_next()) {
+      Page* p = it.next();
+      UpdateMapPointersInRange(p->ObjectAreaStart(), p->AllocationTop());
+    }
+  }
+
+  void UpdateMapPointersInNewSpace() {
+    NewSpace* space = Heap::new_space();
+    UpdateMapPointersInRange(space->bottom(), space->top());
+  }
+
+  void UpdateMapPointersInLargeObjectSpace() {
+    LargeObjectIterator it(Heap::lo_space());
+    while (true) {
+      if (!it.has_next()) break;
+      UpdateMapPointersInObject(it.next());
+    }
+  }
+
+  void Finish() {
+    Heap::map_space()->FinishCompaction(to_evacuate_start_, live_maps_);
+  }
+
+ private:
+  int live_maps_;
+  Address to_evacuate_start_;
+  MapIterator vacant_map_it_;
+  MapIterator map_to_evacuate_it_;
+  Map* first_map_to_evacuate_;
+
+  // Helper class for updating map pointers in HeapObjects.
+  class MapUpdatingVisitor: public ObjectVisitor {
+  public:
+    void VisitPointer(Object** p) {
+      UpdateMapPointer(p);
+    }
+
+    void VisitPointers(Object** start, Object** end) {
+      for (Object** p = start; p < end; p++) UpdateMapPointer(p);
+    }
+
+  private:
+    void UpdateMapPointer(Object** p) {
+      if (!(*p)->IsHeapObject()) return;
+      HeapObject* old_map = reinterpret_cast<HeapObject*>(*p);
+
+      // Moved maps are tagged with overflowed map word.  They are the only
+      // objects those map word is overflowed as marking is already complete.
+      MapWord map_word = old_map->map_word();
+      if (!map_word.IsOverflowed()) return;
+
+      *p = GetForwardedMap(map_word);
+    }
+  };
+
+  static MapUpdatingVisitor map_updating_visitor_;
+
+  static Map* NextMap(MapIterator* it, HeapObject* last, bool live) {
+    while (true) {
+      ASSERT(it->has_next());
+      HeapObject* next = it->next();
+      if (next == last)
+        return NULL;
+      ASSERT(!next->IsOverflowed());
+      ASSERT(!next->IsMarked());
+      ASSERT(next->IsMap() || FreeListNode::IsFreeListNode(next));
+      if (next->IsMap() == live)
+        return reinterpret_cast<Map*>(next);
+    }
+  }
+
+  Map* NextVacantMap() {
+    Map* map = NextMap(&vacant_map_it_, first_map_to_evacuate_, false);
+    ASSERT(map == NULL || FreeListNode::IsFreeListNode(map));
+    return map;
+  }
+
+  Map* NextMapToEvacuate() {
+    Map* map = NextMap(&map_to_evacuate_it_, NULL, true);
+    ASSERT(map != NULL);
+    ASSERT(map->IsMap());
+    return map;
+  }
+
+  static void EvacuateMap(Map* vacant_map, Map* map_to_evacuate) {
+    ASSERT(FreeListNode::IsFreeListNode(vacant_map));
+    ASSERT(map_to_evacuate->IsMap());
+
+    memcpy(
+        reinterpret_cast<void*>(vacant_map->address()),
+        reinterpret_cast<void*>(map_to_evacuate->address()),
+        Map::kSize);
+    ASSERT(vacant_map->IsMap());  // Due to memcpy above.
+
+    MapWord forwarding_map_word = MapWord::FromMap(vacant_map);
+    forwarding_map_word.SetOverflow();
+    map_to_evacuate->set_map_word(forwarding_map_word);
+
+    ASSERT(map_to_evacuate->map_word().IsOverflowed());
+    ASSERT(GetForwardedMap(map_to_evacuate->map_word()) == vacant_map);
+  }
+
+  static Map* GetForwardedMap(MapWord map_word) {
+    ASSERT(map_word.IsOverflowed());
+    map_word.ClearOverflow();
+    Map* new_map = map_word.ToMap();
+    ASSERT_MAP_ALIGNED(new_map->address());
+    return new_map;
+  }
+
+  static int UpdateMapPointersInObject(HeapObject* obj) {
+    ASSERT(!obj->IsMarked());
+    Map* map = obj->map();
+    ASSERT(Heap::map_space()->Contains(map));
+    MapWord map_word = map->map_word();
+    ASSERT(!map_word.IsMarked());
+    if (map_word.IsOverflowed()) {
+      Map* new_map = GetForwardedMap(map_word);
+      ASSERT(Heap::map_space()->Contains(new_map));
+      obj->set_map(new_map);
+
+#ifdef DEBUG
+      if (FLAG_gc_verbose) {
+        PrintF("update %p : %p -> %p\n", obj->address(),
+              map, new_map);
+      }
+#endif
+    }
+
+    int size = obj->SizeFromMap(map);
+    obj->IterateBody(map->instance_type(), size, &map_updating_visitor_);
+    return size;
+  }
+
+  static void UpdateMapPointersInRange(Address start, Address end) {
+    HeapObject* object;
+    int size;
+    for (Address current = start; current < end; current += size) {
+      object = HeapObject::FromAddress(current);
+      size = UpdateMapPointersInObject(object);
+      ASSERT(size > 0);
+    }
+  }
+
+#ifdef DEBUG
+  void CheckNoMapsToEvacuate() {
+    if (!FLAG_enable_slow_asserts)
+      return;
+
+    while (map_to_evacuate_it_.has_next())
+      ASSERT(FreeListNode::IsFreeListNode(map_to_evacuate_it_.next()));
+  }
+#endif
+};
+
+MapCompact::MapUpdatingVisitor MapCompact::map_updating_visitor_;
+
+
 void MarkCompactCollector::SweepSpaces() {
   ASSERT(state_ == SWEEP_SPACES);
   ASSERT(!IsCompacting());
@@ -1254,6 +1475,26 @@
   SweepSpace(Heap::cell_space(), &DeallocateCellBlock);
   SweepSpace(Heap::new_space());
   SweepSpace(Heap::map_space(), &DeallocateMapBlock);
+  int live_maps = Heap::map_space()->Size() / Map::kSize;
+  ASSERT(live_map_objects_ == live_maps);
+
+  if (Heap::map_space()->NeedsCompaction(live_maps)) {
+    MapCompact map_compact(live_maps);
+
+    map_compact.CompactMaps();
+    map_compact.UpdateMapPointersInRoots();
+
+    map_compact.FinishMapSpace();
+    PagedSpaces spaces;
+    while (PagedSpace* space = spaces.next()) {
+      if (space == Heap::map_space()) continue;
+      map_compact.UpdateMapPointersInPagedSpace(space);
+    }
+    map_compact.UpdateMapPointersInNewSpace();
+    map_compact.UpdateMapPointersInLargeObjectSpace();
+
+    map_compact.Finish();
+  }
 }
 
 
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 2da2b1f..02aedb3 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -92,7 +92,15 @@
   static bool HasCompacted() { return compacting_collection_; }
 
   // True after the Prepare phase if the compaction is taking place.
-  static bool IsCompacting() { return compacting_collection_; }
+  static bool IsCompacting() {
+#ifdef DEBUG
+    // For the purposes of asserts we don't want this to keep returning true
+    // after the collection is completed.
+    return state_ != IDLE && compacting_collection_;
+#else
+    return compacting_collection_;
+#endif
+  }
 
   // The count of the number of objects left marked at the end of the last
   // completed full GC (expected to be zero).
diff --git a/src/math.js b/src/math.js
index 07f7295..d804648 100644
--- a/src/math.js
+++ b/src/math.js
@@ -84,7 +84,7 @@
 // ECMA 262 - 15.8.2.7
 function MathCos(x) {
   if (!IS_NUMBER(x)) x = ToNumber(x);
-  return %_Math_cos(x);
+  return %Math_cos(x);
 }
 
 // ECMA 262 - 15.8.2.8
@@ -98,12 +98,12 @@
   if (!IS_NUMBER(x)) x = ToNumber(x);
   // It's more common to call this with a positive number that's out
   // of range than negative numbers; check the upper bound first.
-  if (x <= 0x7FFFFFFF && x > 0) {
+  if (x < 0x80000000 && x > 0) {
     // Numbers in the range [0, 2^31) can be floored by converting
     // them to an unsigned 32-bit value using the shift operator.
     // We avoid doing so for -0, because the result of Math.floor(-0)
     // has to be -0, which wouldn't be the case with the shift.
-    return x << 0;
+    return TO_UINT32(x);
   } else {
     return %Math_floor(x);
   }
@@ -176,7 +176,7 @@
 // ECMA 262 - 15.8.2.16
 function MathSin(x) {
   if (!IS_NUMBER(x)) x = ToNumber(x);
-  return %_Math_sin(x);
+  return %Math_sin(x);
 }
 
 // ECMA 262 - 15.8.2.17
diff --git a/src/messages.js b/src/messages.js
index bdcbf91..d3c8fcc 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -178,7 +178,9 @@
       result_not_primitive:         "Result of %0 must be a primitive, was %1",
       invalid_json:                 "String '%0' is not valid JSON",
       circular_structure:           "Converting circular structure to JSON",
-      object_keys_non_object:       "Object.keys called on non-object"
+      object_keys_non_object:       "Object.keys called on non-object",
+      object_get_prototype_non_object: "Object.getPrototypeOf called on non-object",
+      array_indexof_not_defined:    "Array.getIndexOf: Argument undefined"
     };
   }
   var format = kMessages[message.type];
diff --git a/src/mksnapshot.cc b/src/mksnapshot.cc
index eb743f8..b889e2e 100644
--- a/src/mksnapshot.cc
+++ b/src/mksnapshot.cc
@@ -151,6 +151,7 @@
   }
   i::Serializer::Enable();
   Persistent<Context> context = v8::Context::New();
+  ASSERT(!context.IsEmpty());
   // Make sure all builtin scripts are cached.
   { HandleScope scope;
     for (int i = 0; i < i::Natives::GetBuiltinsCount(); i++) {
diff --git a/src/objects-debug.cc b/src/objects-debug.cc
index 36f65ee..7e77e81 100644
--- a/src/objects-debug.cc
+++ b/src/objects-debug.cc
@@ -587,7 +587,6 @@
     case JS_BUILTINS_OBJECT_TYPE: return "JS_BUILTINS_OBJECT";
     case JS_GLOBAL_PROXY_TYPE: return "JS_GLOBAL_PROXY";
     case PROXY_TYPE: return "PROXY";
-    case SMI_TYPE: return "SMI";
 #define MAKE_STRUCT_CASE(NAME, Name, name) case NAME##_TYPE: return #NAME;
   STRUCT_LIST(MAKE_STRUCT_CASE)
 #undef MAKE_STRUCT_CASE
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 4569038..3003342 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -150,8 +150,12 @@
 bool Object::IsSymbol() {
   if (!this->IsHeapObject()) return false;
   uint32_t type = HeapObject::cast(this)->map()->instance_type();
-  return (type & (kIsNotStringMask | kIsSymbolMask)) ==
-         (kStringTag | kSymbolTag);
+  // Because the symbol tag is non-zero and no non-string types have the
+  // symbol bit set we can test for symbols with a very simple test
+  // operation.
+  ASSERT(kSymbolTag != 0);
+  ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
+  return (type & kIsSymbolMask) != 0;
 }
 
 
@@ -226,7 +230,8 @@
 
 bool StringShape::IsSymbol() {
   ASSERT(valid());
-  return (type_ & kIsSymbolMask) == kSymbolTag;
+  ASSERT(kSymbolTag != 0);
+  return (type_ & kIsSymbolMask) != 0;
 }
 
 
@@ -336,8 +341,8 @@
     return false;
   InstanceType instance_type =
       HeapObject::cast(this)->map()->instance_type();
-  return (instance_type >= EXTERNAL_BYTE_ARRAY_TYPE &&
-          instance_type <= EXTERNAL_FLOAT_ARRAY_TYPE);
+  return (instance_type >= FIRST_EXTERNAL_ARRAY_TYPE &&
+          instance_type <= LAST_EXTERNAL_ARRAY_TYPE);
 }
 
 
diff --git a/src/objects.cc b/src/objects.cc
index 77fbc6b..118c489 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -6834,10 +6834,14 @@
 
 
 template<typename Shape, typename Key>
-Object* HashTable<Shape, Key>::Allocate(
-    int at_least_space_for) {
+Object* HashTable<Shape, Key>::Allocate(int at_least_space_for) {
   int capacity = RoundUpToPowerOf2(at_least_space_for);
-  if (capacity < 4) capacity = 4;  // Guarantee min capacity.
+  if (capacity < 4) {
+    capacity = 4;  // Guarantee min capacity.
+  } else if (capacity > HashTable::kMaxCapacity) {
+    return Failure::OutOfMemoryException();
+  }
+
   Object* obj = Heap::AllocateHashTable(EntryToIndex(capacity));
   if (!obj->IsFailure()) {
     HashTable::cast(obj)->SetNumberOfElements(0);
@@ -6848,30 +6852,18 @@
 }
 
 
-
-// Find entry for key otherwise return -1.
+// Find entry for key otherwise return kNotFound.
 template<typename Shape, typename Key>
 int HashTable<Shape, Key>::FindEntry(Key key) {
-  uint32_t nof = NumberOfElements();
-  if (nof == 0) return kNotFound;  // Bail out if empty.
-
   uint32_t capacity = Capacity();
-  uint32_t hash = Shape::Hash(key);
-  uint32_t entry = GetProbe(hash, 0, capacity);
-
-  Object* element = KeyAt(entry);
-  uint32_t passed_elements = 0;
-  if (!element->IsNull()) {
-    if (!element->IsUndefined() && Shape::IsMatch(key, element)) return entry;
-    if (++passed_elements == nof) return kNotFound;
-  }
-  for (uint32_t i = 1; !element->IsUndefined(); i++) {
-    entry = GetProbe(hash, i, capacity);
-    element = KeyAt(entry);
-    if (!element->IsNull()) {
-      if (!element->IsUndefined() && Shape::IsMatch(key, element)) return entry;
-      if (++passed_elements == nof) return kNotFound;
-    }
+  uint32_t entry = FirstProbe(Shape::Hash(key), capacity);
+  uint32_t count = 1;
+  // EnsureCapacity will guarantee the hash table is never full.
+  while (true) {
+    Object* element = KeyAt(entry);
+    if (element->IsUndefined()) break;  // Empty entry.
+    if (!element->IsNull() && Shape::IsMatch(key, element)) return entry;
+    entry = NextProbe(entry, count++, capacity);
   }
   return kNotFound;
 }
@@ -6918,17 +6910,18 @@
 }
 
 
+
 template<typename Shape, typename Key>
 uint32_t HashTable<Shape, Key>::FindInsertionEntry(uint32_t hash) {
   uint32_t capacity = Capacity();
-  uint32_t entry = GetProbe(hash, 0, capacity);
-  Object* element = KeyAt(entry);
-
-  for (uint32_t i = 1; !(element->IsUndefined() || element->IsNull()); i++) {
-    entry = GetProbe(hash, i, capacity);
-    element = KeyAt(entry);
+  uint32_t entry = FirstProbe(hash, capacity);
+  uint32_t count = 1;
+  // EnsureCapacity will guarantee the hash table is never full.
+  while (true) {
+    Object* element = KeyAt(entry);
+    if (element->IsUndefined() || element->IsNull()) break;
+    entry = NextProbe(entry, count++, capacity);
   }
-
   return entry;
 }
 
@@ -7007,6 +7000,10 @@
 template
 int Dictionary<StringDictionaryShape, String*>::NumberOfEnumElements();
 
+template
+int HashTable<NumberDictionaryShape, uint32_t>::FindEntry(uint32_t);
+
+
 // Collates undefined and unexisting elements below limit from position
 // zero of the elements. The object stays in Dictionary mode.
 Object* JSObject::PrepareSlowElementsForSort(uint32_t limit) {
diff --git a/src/objects.h b/src/objects.h
index 1cdd91e..5d088e5 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -204,14 +204,13 @@
 // instance_type is JS_OBJECT_TYPE.
 //
 // The names of the string instance types are intended to systematically
-// mirror their encoding in the instance_type field of the map.  The length
-// (SHORT, MEDIUM, or LONG) is always mentioned.  The default encoding is
-// considered TWO_BYTE.  It is not mentioned in the name.  ASCII encoding is
-// mentioned explicitly in the name.  Likewise, the default representation is
-// considered sequential.  It is not mentioned in the name.  The other
-// representations (eg, CONS, EXTERNAL) are explicitly mentioned.
-// Finally, the string is either a SYMBOL_TYPE (if it is a symbol) or a
-// STRING_TYPE (if it is not a symbol).
+// mirror their encoding in the instance_type field of the map.  The default
+// encoding is considered TWO_BYTE.  It is not mentioned in the name.  ASCII
+// encoding is mentioned explicitly in the name.  Likewise, the default
+// representation is considered sequential.  It is not mentioned in the
+// name.  The other representations (eg, CONS, EXTERNAL) are explicitly
+// mentioned.  Finally, the string is either a SYMBOL_TYPE (if it is a
+// symbol) or a STRING_TYPE (if it is not a symbol).
 //
 // NOTE: The following things are some that depend on the string types having
 // instance_types that are less than those of all other types:
@@ -237,11 +236,11 @@
   V(PRIVATE_EXTERNAL_ASCII_STRING_TYPE)                                        \
                                                                                \
   V(MAP_TYPE)                                                                  \
-  V(HEAP_NUMBER_TYPE)                                                          \
-  V(FIXED_ARRAY_TYPE)                                                          \
   V(CODE_TYPE)                                                                 \
   V(JS_GLOBAL_PROPERTY_CELL_TYPE)                                              \
   V(ODDBALL_TYPE)                                                              \
+                                                                               \
+  V(HEAP_NUMBER_TYPE)                                                          \
   V(PROXY_TYPE)                                                                \
   V(BYTE_ARRAY_TYPE)                                                           \
   V(PIXEL_ARRAY_TYPE)                                                          \
@@ -257,6 +256,7 @@
   V(EXTERNAL_FLOAT_ARRAY_TYPE)                                                 \
   V(FILLER_TYPE)                                                               \
                                                                                \
+  V(FIXED_ARRAY_TYPE)                                                          \
   V(ACCESSOR_INFO_TYPE)                                                        \
   V(ACCESS_CHECK_INFO_TYPE)                                                    \
   V(INTERCEPTOR_INFO_TYPE)                                                     \
@@ -383,11 +383,12 @@
 const uint32_t kStringTag = 0x0;
 const uint32_t kNotStringTag = 0x80;
 
-// If bit 7 is clear, bit 5 indicates that the string is a symbol (if set) or
-// not (if cleared).
-const uint32_t kIsSymbolMask = 0x20;
+// Bit 6 indicates that the object is a symbol (if set) or not (if cleared).
+// There are not enough types that the non-string types (with bit 7 set) can
+// have bit 6 set too.
+const uint32_t kIsSymbolMask = 0x40;
 const uint32_t kNotSymbolTag = 0x0;
-const uint32_t kSymbolTag = 0x20;
+const uint32_t kSymbolTag = 0x40;
 
 // If bit 7 is clear then bit 2 indicates whether the string consists of
 // two-byte characters or one-byte characters.
@@ -418,6 +419,7 @@
 
 
 enum InstanceType {
+  // String types.
   SYMBOL_TYPE = kSymbolTag | kSeqStringTag,
   ASCII_SYMBOL_TYPE = kAsciiStringTag | kSymbolTag | kSeqStringTag,
   CONS_SYMBOL_TYPE = kSymbolTag | kConsStringTag,
@@ -433,56 +435,66 @@
   EXTERNAL_ASCII_STRING_TYPE = kAsciiStringTag | kExternalStringTag,
   PRIVATE_EXTERNAL_ASCII_STRING_TYPE = EXTERNAL_ASCII_STRING_TYPE,
 
-  MAP_TYPE = kNotStringTag,
-  HEAP_NUMBER_TYPE,
-  FIXED_ARRAY_TYPE,
+  // Objects allocated in their own spaces (never in new space).
+  MAP_TYPE = kNotStringTag,  // FIRST_NONSTRING_TYPE
   CODE_TYPE,
   ODDBALL_TYPE,
   JS_GLOBAL_PROPERTY_CELL_TYPE,
+
+  // "Data", objects that cannot contain non-map-word pointers to heap
+  // objects.
+  HEAP_NUMBER_TYPE,
   PROXY_TYPE,
   BYTE_ARRAY_TYPE,
   PIXEL_ARRAY_TYPE,
-  EXTERNAL_BYTE_ARRAY_TYPE,
+  EXTERNAL_BYTE_ARRAY_TYPE,  // FIRST_EXTERNAL_ARRAY_TYPE
   EXTERNAL_UNSIGNED_BYTE_ARRAY_TYPE,
   EXTERNAL_SHORT_ARRAY_TYPE,
   EXTERNAL_UNSIGNED_SHORT_ARRAY_TYPE,
   EXTERNAL_INT_ARRAY_TYPE,
   EXTERNAL_UNSIGNED_INT_ARRAY_TYPE,
-  EXTERNAL_FLOAT_ARRAY_TYPE,
-  FILLER_TYPE,
-  SMI_TYPE,
+  EXTERNAL_FLOAT_ARRAY_TYPE,  // LAST_EXTERNAL_ARRAY_TYPE
+  FILLER_TYPE,  // LAST_DATA_TYPE
 
+  // Structs.
   ACCESSOR_INFO_TYPE,
   ACCESS_CHECK_INFO_TYPE,
   INTERCEPTOR_INFO_TYPE,
-  SHARED_FUNCTION_INFO_TYPE,
   CALL_HANDLER_INFO_TYPE,
   FUNCTION_TEMPLATE_INFO_TYPE,
   OBJECT_TEMPLATE_INFO_TYPE,
   SIGNATURE_INFO_TYPE,
   TYPE_SWITCH_INFO_TYPE,
+  SCRIPT_TYPE,
 #ifdef ENABLE_DEBUGGER_SUPPORT
   DEBUG_INFO_TYPE,
   BREAK_POINT_INFO_TYPE,
 #endif
-  SCRIPT_TYPE,
 
-  JS_VALUE_TYPE,
+  FIXED_ARRAY_TYPE,
+  SHARED_FUNCTION_INFO_TYPE,
+
+  JS_VALUE_TYPE,  // FIRST_JS_OBJECT_TYPE
   JS_OBJECT_TYPE,
   JS_CONTEXT_EXTENSION_OBJECT_TYPE,
   JS_GLOBAL_OBJECT_TYPE,
   JS_BUILTINS_OBJECT_TYPE,
   JS_GLOBAL_PROXY_TYPE,
   JS_ARRAY_TYPE,
-  JS_REGEXP_TYPE,
+  JS_REGEXP_TYPE,  // LAST_JS_OBJECT_TYPE
 
   JS_FUNCTION_TYPE,
 
   // Pseudo-types
-  FIRST_NONSTRING_TYPE = MAP_TYPE,
   FIRST_TYPE = 0x0,
-  INVALID_TYPE = FIRST_TYPE - 1,
   LAST_TYPE = JS_FUNCTION_TYPE,
+  INVALID_TYPE = FIRST_TYPE - 1,
+  FIRST_NONSTRING_TYPE = MAP_TYPE,
+  // Boundaries for testing for an external array.
+  FIRST_EXTERNAL_ARRAY_TYPE = EXTERNAL_BYTE_ARRAY_TYPE,
+  LAST_EXTERNAL_ARRAY_TYPE = EXTERNAL_FLOAT_ARRAY_TYPE,
+  // Boundary for promotion to old data space/old pointer space.
+  LAST_DATA_TYPE = FILLER_TYPE,
   // Boundaries for testing the type is a JavaScript "object".  Note that
   // function objects are not counted as objects, even though they are
   // implemented as such; only values whose typeof is "object" are included.
@@ -1497,6 +1509,10 @@
 #endif
   Object* SlowReverseLookup(Object* value);
 
+  // Maximal number of elements (numbered 0 .. kMaxElementCount - 1).
+  // Also maximal value of JSArray's length property.
+  static const uint32_t kMaxElementCount = 0xffffffffu;
+
   static const uint32_t kMaxGap = 1024;
   static const int kMaxFastElementsLength = 5000;
   static const int kInitialMaxFastElementArray = 100000;
@@ -1623,8 +1639,14 @@
   // Casting.
   static inline FixedArray* cast(Object* obj);
 
-  // Align data at kPointerSize, even if Array.kHeaderSize isn't aligned.
-  static const int kHeaderSize = POINTER_SIZE_ALIGN(Array::kHeaderSize);
+  static const int kHeaderSize = Array::kAlignedSize;
+
+  // Maximal allowed size, in bytes, of a single FixedArray.
+  // Prevents overflowing size computations, as well as extreme memory
+  // consumption.
+  static const int kMaxSize = 512 * MB;
+  // Maximally allowed length of a FixedArray.
+  static const int kMaxLength = (kMaxSize - kHeaderSize) / kPointerSize;
 
   // Dispatched behavior.
   int FixedArraySize() { return SizeFor(length()); }
@@ -1937,6 +1959,12 @@
   // Constant used for denoting a absent entry.
   static const int kNotFound = -1;
 
+  // Maximal capacity of HashTable. Based on maximal length of underlying
+  // FixedArray. Staying below kMaxCapacity also ensures that EntryToIndex
+  // cannot overflow.
+  static const int kMaxCapacity =
+      (FixedArray::kMaxLength - kElementsStartOffset) / kEntrySize;
+
   // Find entry for key otherwise return -1.
   int FindEntry(Key key);
 
@@ -1967,6 +1995,7 @@
     // use bit-wise AND with a mask, so the capacity must be positive
     // and non-zero.
     ASSERT(capacity > 0);
+    ASSERT(capacity <= kMaxCapacity);
     fast_set(this, kCapacityIndex, Smi::FromInt(capacity));
   }
 
@@ -1977,6 +2006,14 @@
     return (hash + GetProbeOffset(number)) & (size - 1);
   }
 
+  static uint32_t FirstProbe(uint32_t hash, uint32_t size) {
+    return hash & (size - 1);
+  }
+
+  static uint32_t NextProbe(uint32_t last, uint32_t number, uint32_t size) {
+    return (last + number) & (size - 1);
+  }
+
   // Ensure enough space for n additional elements.
   Object* EnsureCapacity(int n, Key key);
 };
@@ -2306,6 +2343,11 @@
   static const int kHeaderSize = Array::kHeaderSize;
   static const int kAlignedSize = Array::kAlignedSize;
 
+  // Maximal memory consumption for a single ByteArray.
+  static const int kMaxSize = 512 * MB;
+  // Maximal length of a single ByteArray.
+  static const int kMaxLength = kMaxSize - kHeaderSize;
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ByteArray);
 };
@@ -3592,6 +3634,14 @@
   static const int kIrregexpCaptureCountIndex = kDataIndex + 3;
 
   static const int kIrregexpDataSize = kIrregexpCaptureCountIndex + 1;
+
+  // Offsets directly into the data fixed array.
+  static const int kDataTagOffset =
+      FixedArray::kHeaderSize + kTagIndex * kPointerSize;
+  static const int kDataAsciiCodeOffset =
+      FixedArray::kHeaderSize + kIrregexpASCIICodeIndex * kPointerSize;
+  static const int kIrregexpCaptureCountOffset =
+      FixedArray::kHeaderSize + kIrregexpCaptureCountIndex * kPointerSize;
 };
 
 
@@ -4015,6 +4065,12 @@
   static const int kHeaderSize = String::kSize;
   static const int kAlignedSize = POINTER_SIZE_ALIGN(kHeaderSize);
 
+  // Maximal memory usage for a single sequential ASCII string.
+  static const int kMaxSize = 512 * MB;
+  // Maximal length of a single sequential ASCII string.
+  // Q.v. String::kMaxLength which is the maximal size of concatenated strings.
+  static const int kMaxLength = (kMaxSize - kHeaderSize);
+
   // Support for StringInputBuffer.
   inline void SeqAsciiStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
                                                 unsigned* offset,
@@ -4061,6 +4117,12 @@
   static const int kHeaderSize = String::kSize;
   static const int kAlignedSize = POINTER_SIZE_ALIGN(kHeaderSize);
 
+  // Maximal memory usage for a single sequential two-byte string.
+  static const int kMaxSize = 512 * MB;
+  // Maximal length of a single sequential two-byte string.
+  // Q.v. String::kMaxLength which is the maximal size of concatenated strings.
+  static const int kMaxLength = (kMaxSize - kHeaderSize) / sizeof(uint16_t);
+
   // Support for StringInputBuffer.
   inline void SeqTwoByteStringReadBlockIntoBuffer(ReadBlockBuffer* buffer,
                                                   unsigned* offset_ptr,
diff --git a/src/parser.cc b/src/parser.cc
index a3bc6da..4090a08 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -371,7 +371,7 @@
   void AddAtom(RegExpTree* tree);
   void AddAssertion(RegExpTree* tree);
   void NewAlternative();  // '|'
-  void AddQuantifierToAtom(int min, int max, bool is_greedy);
+  void AddQuantifierToAtom(int min, int max, RegExpQuantifier::Type type);
   RegExpTree* ToRegExp();
  private:
   void FlushCharacters();
@@ -503,7 +503,9 @@
 }
 
 
-void RegExpBuilder::AddQuantifierToAtom(int min, int max, bool is_greedy) {
+void RegExpBuilder::AddQuantifierToAtom(int min,
+                                        int max,
+                                        RegExpQuantifier::Type type) {
   if (pending_empty_) {
     pending_empty_ = false;
     return;
@@ -543,7 +545,7 @@
     UNREACHABLE();
     return;
   }
-  terms_.Add(new RegExpQuantifier(min, max, is_greedy, atom));
+  terms_.Add(new RegExpQuantifier(min, max, type, atom));
   LAST(ADD_TERM);
 }
 
@@ -3332,7 +3334,7 @@
     ArrayLiteral* array_literal = expression->AsArrayLiteral();
     ASSERT(array_literal != NULL && array_literal->is_simple());
     result->set(kTypeSlot, Smi::FromInt(ARRAY_LITERAL));
-    result->set(kElementsSlot, *array_literal->literals());
+    result->set(kElementsSlot, *array_literal->constant_elements());
   }
   return result;
 }
@@ -3596,7 +3598,7 @@
           top_scope_->NewUnresolved(function_name, inside_with());
       fproxy->BindTo(fvar);
       body.Add(new ExpressionStatement(
-                   new Assignment(Token::INIT_VAR, fproxy,
+                   new Assignment(Token::INIT_CONST, fproxy,
                                   NEW(ThisFunction()),
                                   RelocInfo::kNoPosition)));
     }
@@ -4278,12 +4280,16 @@
     default:
       continue;
     }
-    bool is_greedy = true;
+    RegExpQuantifier::Type type = RegExpQuantifier::GREEDY;
     if (current() == '?') {
-      is_greedy = false;
+      type = RegExpQuantifier::NON_GREEDY;
+      Advance();
+    } else if (FLAG_regexp_possessive_quantifier && current() == '+') {
+      // FLAG_regexp_possessive_quantifier is a debug-only flag.
+      type = RegExpQuantifier::POSSESSIVE;
       Advance();
     }
-    builder->AddQuantifierToAtom(min, max, is_greedy);
+    builder->AddQuantifierToAtom(min, max, type);
   }
 }
 
@@ -4705,6 +4711,11 @@
 }
 
 
+bool ScriptDataImpl::HasError() {
+  return has_error();
+}
+
+
 ScriptDataImpl* PreParse(Handle<String> source,
                          unibrow::CharacterStream* stream,
                          v8::Extension* extension) {
diff --git a/src/parser.h b/src/parser.h
index 7328e81..a67284c 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -91,6 +91,7 @@
   virtual ~ScriptDataImpl();
   virtual int Length();
   virtual unsigned* Data();
+  virtual bool HasError();
   FunctionEntry GetFunctionEnd(int start);
   bool SanityCheck();
 
diff --git a/src/regexp-delay.js b/src/regexp-delay.js
index 14c3644..7bec455 100644
--- a/src/regexp-delay.js
+++ b/src/regexp-delay.js
@@ -136,13 +136,7 @@
 
 
 function DoRegExpExec(regexp, string, index) {
-  return %RegExpExec(regexp, string, index, lastMatchInfo);
-}
-
-
-function DoRegExpExecGlobal(regexp, string) {
-  // Returns an array of arrays of substring indices.
-  return %RegExpExecGlobal(regexp, string, lastMatchInfo);
+  return %_RegExpExec(regexp, string, index, lastMatchInfo);
 }
 
 
@@ -170,7 +164,7 @@
 
   %_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
   // matchIndices is either null or the lastMatchInfo array.
-  var matchIndices = %RegExpExec(this, s, i, lastMatchInfo);
+  var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
 
   if (matchIndices == null) {
     if (this.global) this.lastIndex = 0;
@@ -227,7 +221,7 @@
 
   %_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
   // matchIndices is either null or the lastMatchInfo array.
-  var matchIndices = %RegExpExec(this, s, i, lastMatchInfo);
+  var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
 
   if (matchIndices == null) {
     if (this.global) this.lastIndex = 0;
diff --git a/src/regexp-macro-assembler-tracer.cc b/src/regexp-macro-assembler-tracer.cc
index 0aad337..c5c2919 100644
--- a/src/regexp-macro-assembler-tracer.cc
+++ b/src/regexp-macro-assembler-tracer.cc
@@ -307,18 +307,11 @@
 
 bool RegExpMacroAssemblerTracer::CheckSpecialCharacterClass(
     uc16 type,
-    int cp_offset,
-    bool check_offset,
     Label* on_no_match) {
   bool supported = assembler_->CheckSpecialCharacterClass(type,
-                                                          cp_offset,
-                                                          check_offset,
                                                           on_no_match);
-  PrintF(" CheckSpecialCharacterClass(type='%c', offset=%d, "
-             "check_offset=%s, label[%08x]): %s;\n",
+  PrintF(" CheckSpecialCharacterClass(type='%c', label[%08x]): %s;\n",
          type,
-         cp_offset,
-         check_offset ? "true" : "false",
          on_no_match,
          supported ? "true" : "false");
   return supported;
diff --git a/src/regexp-macro-assembler-tracer.h b/src/regexp-macro-assembler-tracer.h
index 28ca5f3..9608f9e 100644
--- a/src/regexp-macro-assembler-tracer.h
+++ b/src/regexp-macro-assembler-tracer.h
@@ -69,8 +69,6 @@
                                               uc16 and_with,
                                               Label* on_not_equal);
   virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
                                           Label* on_no_match);
   virtual void Fail();
   virtual Handle<Object> GetCode(Handle<String> source);
diff --git a/src/regexp-macro-assembler.cc b/src/regexp-macro-assembler.cc
index 9ae19d7..c73e02a 100644
--- a/src/regexp-macro-assembler.cc
+++ b/src/regexp-macro-assembler.cc
@@ -143,17 +143,6 @@
                        input_end,
                        offsets_vector,
                        previous_index == 0);
-
-  if (res == SUCCESS) {
-    // Capture values are relative to start_offset only.
-    // Convert them to be relative to start of string.
-    for (int i = 0; i < offsets_vector_length; i++) {
-      if (offsets_vector[i] >= 0) {
-        offsets_vector[i] += previous_index;
-      }
-    }
-  }
-
   return res;
 }
 
@@ -167,7 +156,7 @@
     int* output,
     bool at_start) {
   typedef int (*matcher)(String*, int, const byte*,
-                         const byte*, int*, int, Address);
+                         const byte*, int*, int, Address, int);
   matcher matcher_func = FUNCTION_CAST<matcher>(code->entry());
 
   int at_start_val = at_start ? 1 : 0;
@@ -176,6 +165,7 @@
   RegExpStack stack;
   Address stack_base = RegExpStack::stack_base();
 
+  int direct_call = 0;
   int result = CALL_GENERATED_REGEXP_CODE(matcher_func,
                                           input,
                                           start_offset,
@@ -183,7 +173,8 @@
                                           input_end,
                                           output,
                                           at_start_val,
-                                          stack_base);
+                                          stack_base,
+                                          direct_call);
   ASSERT(result <= SUCCESS);
   ASSERT(result >= RETRY);
 
diff --git a/src/regexp-macro-assembler.h b/src/regexp-macro-assembler.h
index aa01096..7cc9511 100644
--- a/src/regexp-macro-assembler.h
+++ b/src/regexp-macro-assembler.h
@@ -123,8 +123,6 @@
   // not have custom support.
   // May clobber the current loaded character.
   virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
                                           Label* on_no_match) {
     return false;
   }
diff --git a/src/regexp-stack.h b/src/regexp-stack.h
index fbaa6fb..b4fa2e9 100644
--- a/src/regexp-stack.h
+++ b/src/regexp-stack.h
@@ -98,12 +98,24 @@
     void Free();
   };
 
+  // Address of allocated memory.
+  static Address memory_address() {
+    return reinterpret_cast<Address>(&thread_local_.memory_);
+  }
+
+  // Address of size of allocated memory.
+  static Address memory_size_address() {
+    return reinterpret_cast<Address>(&thread_local_.memory_size_);
+  }
+
   // Resets the buffer if it has grown beyond the default/minimum size.
   // After this, the buffer is either the default size, or it is empty, so
   // you have to call EnsureCapacity before using it again.
   static void Reset();
 
   static ThreadLocal thread_local_;
+
+  friend class ExternalReference;
 };
 
 }}  // namespace v8::internal
diff --git a/src/runtime.cc b/src/runtime.cc
index c62f8fd..3a6e176 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -559,6 +559,73 @@
 }
 
 
+// Recursively traverses hidden prototypes if property is not found
+static void GetOwnPropertyImplementation(JSObject* obj,
+                                         String* name,
+                                         LookupResult* result) {
+  obj->LocalLookupRealNamedProperty(name, result);
+
+  if (!result->IsProperty()) {
+    Object* proto = obj->GetPrototype();
+    if (proto->IsJSObject() &&
+      JSObject::cast(proto)->map()->is_hidden_prototype())
+      GetOwnPropertyImplementation(JSObject::cast(proto),
+                                   name, result);
+  }
+}
+
+
+// Returns an array with the property description:
+//  if args[1] is not a property on args[0]
+//          returns undefined
+//  if args[1] is a data property on args[0]
+//         [false, value, Writeable, Enumerable, Configurable]
+//  if args[1] is an accessor on args[0]
+//         [true, GetFunction, SetFunction, Enumerable, Configurable]
+static Object* Runtime_GetOwnProperty(Arguments args) {
+  HandleScope scope;
+  Handle<FixedArray> elms = Factory::NewFixedArray(5);
+  Handle<JSArray> desc = Factory::NewJSArrayWithElements(elms);
+  LookupResult result;
+  CONVERT_CHECKED(JSObject, obj, args[0]);
+  CONVERT_CHECKED(String, name, args[1]);
+
+  // Use recursive implementation to also traverse hidden prototypes
+  GetOwnPropertyImplementation(obj, name, &result);
+
+  if (!result.IsProperty())
+    return Heap::undefined_value();
+
+  if (result.type() == CALLBACKS) {
+    Object* structure = result.GetCallbackObject();
+    if (structure->IsProxy()) {
+      // Property that is internally implemented as a callback.
+      Object* value = obj->GetPropertyWithCallback(
+          obj, structure, name, result.holder());
+      elms->set(0, Heap::false_value());
+      elms->set(1, value);
+      elms->set(2, Heap::ToBoolean(!result.IsReadOnly()));
+    } else if (structure->IsFixedArray()) {
+      // __defineGetter__/__defineSetter__ callback.
+      elms->set(0, Heap::true_value());
+      elms->set(1, FixedArray::cast(structure)->get(0));
+      elms->set(2, FixedArray::cast(structure)->get(1));
+    } else {
+      // TODO(ricow): Handle API callbacks.
+      return Heap::undefined_value();
+    }
+  } else {
+    elms->set(0, Heap::false_value());
+    elms->set(1, result.GetLazyValue());
+    elms->set(2, Heap::ToBoolean(!result.IsReadOnly()));
+  }
+
+  elms->set(3, Heap::ToBoolean(!result.IsDontEnum()));
+  elms->set(4, Heap::ToBoolean(!result.IsReadOnly()));
+  return *desc;
+}
+
+
 static Object* Runtime_RegExpCompile(Arguments args) {
   HandleScope scope;
   ASSERT(args.length() == 3);
@@ -1158,6 +1225,7 @@
   RUNTIME_ASSERT(last_match_info->HasFastElements());
   RUNTIME_ASSERT(index >= 0);
   RUNTIME_ASSERT(index <= subject->length());
+  Counters::regexp_entry_runtime.Increment();
   Handle<Object> result = RegExpImpl::Exec(regexp,
                                            subject,
                                            index,
@@ -1384,6 +1452,17 @@
 }
 
 
+static Object* CharFromCode(Object* char_code) {
+  uint32_t code;
+  if (Array::IndexFromObject(char_code, &code)) {
+    if (code <= 0xffff) {
+      return Heap::LookupSingleCharacterStringFromCode(code);
+    }
+  }
+  return Heap::empty_string();
+}
+
+
 static Object* Runtime_StringCharCodeAt(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
@@ -1394,16 +1473,20 @@
 }
 
 
+static Object* Runtime_StringCharAt(Arguments args) {
+  NoHandleAllocation ha;
+  ASSERT(args.length() == 2);
+
+  CONVERT_CHECKED(String, subject, args[0]);
+  Object* index = args[1];
+  return CharFromCode(CharCodeAt(subject, index));
+}
+
+
 static Object* Runtime_CharFromCode(Arguments args) {
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
-  uint32_t code;
-  if (Array::IndexFromObject(args[0], &code)) {
-    if (code <= 0xffff) {
-      return Heap::LookupSingleCharacterStringFromCode(code);
-    }
-  }
-  return Heap::empty_string();
+  return CharFromCode(args[0]);
 }
 
 // Forward declarations.
@@ -1509,7 +1592,7 @@
 
 
   void IncrementCharacterCount(int by) {
-    if (character_count_ > Smi::kMaxValue - by) {
+    if (character_count_ > String::kMaxLength - by) {
       V8::FatalProcessOutOfMemory("String.replace result too large.");
     }
     character_count_ += by;
@@ -2473,6 +2556,7 @@
   RUNTIME_ASSERT(end >= start);
   RUNTIME_ASSERT(start >= 0);
   RUNTIME_ASSERT(end <= value->length());
+  Counters::sub_string_runtime.Increment();
   return value->SubString(start, end);
 }
 
@@ -2724,7 +2808,6 @@
 }
 
 
-
 // KeyedStringGetProperty is called from KeyedLoadIC::GenerateGeneric.
 static Object* Runtime_KeyedGetProperty(Arguments args) {
   NoHandleAllocation ha;
@@ -2776,6 +2859,13 @@
         // If value is the hole do the general lookup.
       }
     }
+  } else if (args[0]->IsString() && args[1]->IsSmi()) {
+    // Fast case for string indexing using [] with a smi index.
+    HandleScope scope;
+    Handle<String> str = args.at<String>(0);
+    int index = Smi::cast(args[1])->value();
+    Handle<Object> result = GetCharAt(str, index);
+    return *result;
   }
 
   // Fall back to GetObjectProperty.
@@ -3362,6 +3452,7 @@
         escaped_length += 3;
       }
       // We don't allow strings that are longer than a maximal length.
+      ASSERT(String::kMaxLength < 0x7fffffff - 6);  // Cannot overflow.
       if (escaped_length > String::kMaxLength) {
         Top::context()->mark_out_of_memory();
         return Failure::OutOfMemoryException();
@@ -3908,20 +3999,19 @@
 
 static Object* Runtime_StringBuilderConcat(Arguments args) {
   NoHandleAllocation ha;
-  ASSERT(args.length() == 2);
+  ASSERT(args.length() == 3);
   CONVERT_CHECKED(JSArray, array, args[0]);
-  CONVERT_CHECKED(String, special, args[1]);
+  if (!args[1]->IsSmi()) {
+    Top::context()->mark_out_of_memory();
+    return Failure::OutOfMemoryException();
+  }
+  int array_length = Smi::cast(args[1])->value();
+  CONVERT_CHECKED(String, special, args[2]);
 
   // This assumption is used by the slice encoding in one or two smis.
   ASSERT(Smi::kMaxValue >= String::kMaxLength);
 
   int special_length = special->length();
-  Object* smi_array_length = array->length();
-  if (!smi_array_length->IsSmi()) {
-    Top::context()->mark_out_of_memory();
-    return Failure::OutOfMemoryException();
-  }
-  int array_length = Smi::cast(smi_array_length)->value();
   if (!array->HasFastElements()) {
     return Top::Throw(Heap::illegal_argument_symbol());
   }
@@ -3939,6 +4029,7 @@
 
   bool ascii = special->IsAsciiRepresentation();
   int position = 0;
+  int increment = 0;
   for (int i = 0; i < array_length; i++) {
     Object* elt = fixed_array->get(i);
     if (elt->IsSmi()) {
@@ -3951,10 +4042,10 @@
         if (pos + len > special_length) {
           return Top::Throw(Heap::illegal_argument_symbol());
         }
-        position += len;
+        increment = len;
       } else {
         // Position and length encoded in two smis.
-        position += (-len);
+        increment = (-len);
         // Get the position and check that it is also a smi.
         i++;
         if (i >= array_length) {
@@ -3968,17 +4059,18 @@
     } else if (elt->IsString()) {
       String* element = String::cast(elt);
       int element_length = element->length();
-      position += element_length;
+      increment = element_length;
       if (ascii && !element->IsAsciiRepresentation()) {
         ascii = false;
       }
     } else {
       return Top::Throw(Heap::illegal_argument_symbol());
     }
-    if (position > String::kMaxLength) {
+    if (increment > String::kMaxLength - position) {
       Top::context()->mark_out_of_memory();
       return Failure::OutOfMemoryException();
     }
+    position += increment;
   }
 
   int length = position;
@@ -4192,6 +4284,8 @@
   CONVERT_CHECKED(String, x, args[0]);
   CONVERT_CHECKED(String, y, args[1]);
 
+  Counters::string_compare_runtime.Increment();
+
   // A few fast case tests before we flatten.
   if (x == y) return Smi::FromInt(EQUAL);
   if (y->length() == 0) {
@@ -5227,51 +5321,31 @@
 }
 
 
-static Handle<JSFunction> GetBuiltinFunction(String* name) {
-  LookupResult result;
-  Top::global_context()->builtins()->LocalLookup(name, &result);
-  return Handle<JSFunction>(JSFunction::cast(result.GetValue()));
-}
+static ObjectPair Runtime_ResolvePossiblyDirectEval(Arguments args) {
+  ASSERT(args.length() == 3);
+  if (!args[0]->IsJSFunction()) {
+    return MakePair(Top::ThrowIllegalOperation(), NULL);
+  }
 
-
-static Object* CompileDirectEval(Handle<String> source) {
-  // Compute the eval context.
   HandleScope scope;
+  Handle<JSFunction> callee = args.at<JSFunction>(0);
+  Handle<Object> receiver;  // Will be overwritten.
+
+  // Compute the calling context.
+  Handle<Context> context = Handle<Context>(Top::context());
+#ifdef DEBUG
+  // Make sure Top::context() agrees with the old code that traversed
+  // the stack frames to compute the context.
   StackFrameLocator locator;
   JavaScriptFrame* frame = locator.FindJavaScriptFrame(0);
-  Handle<Context> context(Context::cast(frame->context()));
-  bool is_global = context->IsGlobalContext();
-
-  // Compile source string in the current context.
-  Handle<JSFunction> boilerplate = Compiler::CompileEval(
-      source,
-      context,
-      is_global,
-      Compiler::DONT_VALIDATE_JSON);
-  if (boilerplate.is_null()) return Failure::Exception();
-  Handle<JSFunction> fun =
-      Factory::NewFunctionFromBoilerplate(boilerplate, context, NOT_TENURED);
-  return *fun;
-}
-
-
-static Object* Runtime_ResolvePossiblyDirectEval(Arguments args) {
-  ASSERT(args.length() == 2);
-
-  HandleScope scope;
-
-  CONVERT_ARG_CHECKED(JSFunction, callee, 0);
-
-  Handle<Object> receiver;
+  ASSERT(Context::cast(frame->context()) == *context);
+#endif
 
   // Find where the 'eval' symbol is bound. It is unaliased only if
   // it is bound in the global context.
-  StackFrameLocator locator;
-  JavaScriptFrame* frame = locator.FindJavaScriptFrame(0);
-  Handle<Context> context(Context::cast(frame->context()));
-  int index;
-  PropertyAttributes attributes;
-  while (!context.is_null()) {
+  int index = -1;
+  PropertyAttributes attributes = ABSENT;
+  while (true) {
     receiver = context->Lookup(Factory::eval_symbol(), FOLLOW_PROTOTYPE_CHAIN,
                                &index, &attributes);
     // Stop search when eval is found or when the global context is
@@ -5290,46 +5364,42 @@
     Handle<Object> name = Factory::eval_symbol();
     Handle<Object> reference_error =
         Factory::NewReferenceError("not_defined", HandleVector(&name, 1));
-    return Top::Throw(*reference_error);
+    return MakePair(Top::Throw(*reference_error), NULL);
   }
 
-  if (context->IsGlobalContext()) {
-    // 'eval' is bound in the global context, but it may have been overwritten.
-    // Compare it to the builtin 'GlobalEval' function to make sure.
-    Handle<JSFunction> global_eval =
-      GetBuiltinFunction(Heap::global_eval_symbol());
-    if (global_eval.is_identical_to(callee)) {
-      // A direct eval call.
-      if (args[1]->IsString()) {
-        CONVERT_ARG_CHECKED(String, source, 1);
-        // A normal eval call on a string. Compile it and return the
-        // compiled function bound in the local context.
-        Object* compiled_source = CompileDirectEval(source);
-        if (compiled_source->IsFailure()) return compiled_source;
-        receiver = Handle<Object>(frame->receiver());
-        callee = Handle<JSFunction>(JSFunction::cast(compiled_source));
-      } else {
-        // An eval call that is not called on a string. Global eval
-        // deals better with this.
-        receiver = Handle<Object>(Top::global_context()->global());
-      }
-    } else {
-      // 'eval' is overwritten. Just call the function with the given arguments.
-      receiver = Handle<Object>(Top::global_context()->global());
-    }
-  } else {
+  if (!context->IsGlobalContext()) {
     // 'eval' is not bound in the global context. Just call the function
     // with the given arguments. This is not necessarily the global eval.
     if (receiver->IsContext()) {
       context = Handle<Context>::cast(receiver);
       receiver = Handle<Object>(context->get(index));
+    } else if (receiver->IsJSContextExtensionObject()) {
+      receiver = Handle<JSObject>(Top::context()->global()->global_receiver());
     }
+    return MakePair(*callee, *receiver);
   }
 
-  Handle<FixedArray> call = Factory::NewFixedArray(2);
-  call->set(0, *callee);
-  call->set(1, *receiver);
-  return *call;
+  // 'eval' is bound in the global context, but it may have been overwritten.
+  // Compare it to the builtin 'GlobalEval' function to make sure.
+  if (*callee != Top::global_context()->global_eval_fun() ||
+      !args[1]->IsString()) {
+    return MakePair(*callee, Top::context()->global()->global_receiver());
+  }
+
+  // Deal with a normal eval call with a string argument. Compile it
+  // and return the compiled function bound in the local context.
+  Handle<String> source = args.at<String>(1);
+  Handle<JSFunction> boilerplate = Compiler::CompileEval(
+      source,
+      Handle<Context>(Top::context()),
+      Top::context()->IsGlobalContext(),
+      Compiler::DONT_VALIDATE_JSON);
+  if (boilerplate.is_null()) return MakePair(Failure::Exception(), NULL);
+  callee = Factory::NewFunctionFromBoilerplate(
+      boilerplate,
+      Handle<Context>(Top::context()),
+      NOT_TENURED);
+  return MakePair(*callee, args[2]);
 }
 
 
@@ -5386,11 +5456,11 @@
                      uint32_t index_limit,
                      bool fast_elements) :
       storage_(storage), index_limit_(index_limit),
-      fast_elements_(fast_elements), index_offset_(0) { }
+      index_offset_(0), fast_elements_(fast_elements) { }
 
   void visit(uint32_t i, Handle<Object> elm) {
-    uint32_t index = i + index_offset_;
-    if (index >= index_limit_) return;
+    if (i >= index_limit_ - index_offset_) return;
+    uint32_t index = index_offset_ + i;
 
     if (fast_elements_) {
       ASSERT(index < static_cast<uint32_t>(storage_->length()));
@@ -5406,16 +5476,23 @@
   }
 
   void increase_index_offset(uint32_t delta) {
-    index_offset_ += delta;
+    if (index_limit_ - index_offset_ < delta) {
+      index_offset_ = index_limit_;
+    } else {
+      index_offset_ += delta;
+    }
   }
 
   Handle<FixedArray> storage() { return storage_; }
 
  private:
   Handle<FixedArray> storage_;
+  // Limit on the accepted indices. Elements with indices larger than the
+  // limit are ignored by the visitor.
   uint32_t index_limit_;
-  bool fast_elements_;
+  // Index after last seen index. Always less than or equal to index_limit_.
   uint32_t index_offset_;
+  bool fast_elements_;
 };
 
 
@@ -5587,6 +5664,11 @@
  *
  * If a ArrayConcatVisitor object is given, the visitor is called with
  * parameters, element's index + visitor_index_offset and the element.
+ *
+ * The returned number of elements is an upper bound on the actual number
+ * of elements added. If the same element occurs in more than one object
+ * in the array's prototype chain, it will be counted more than once, but
+ * will only occur once in the result.
  */
 static uint32_t IterateArrayAndPrototypeElements(Handle<JSArray> array,
                                                  ArrayConcatVisitor* visitor) {
@@ -5609,8 +5691,14 @@
   uint32_t nof_elements = 0;
   for (int i = objects.length() - 1; i >= 0; i--) {
     Handle<JSObject> obj = objects[i];
-    nof_elements +=
+    uint32_t encountered_elements =
         IterateElements(Handle<JSObject>::cast(obj), range, visitor);
+
+    if (encountered_elements > JSObject::kMaxElementCount - nof_elements) {
+      nof_elements = JSObject::kMaxElementCount;
+    } else {
+      nof_elements += encountered_elements;
+    }
   }
 
   return nof_elements;
@@ -5627,10 +5715,12 @@
  * elements.  If an argument is not an Array object, the function
  * visits the object as if it is an one-element array.
  *
- * If the result array index overflows 32-bit integer, the rounded
+ * If the result array index overflows 32-bit unsigned integer, the rounded
  * non-negative number is used as new length. For example, if one
  * array length is 2^32 - 1, second array length is 1, the
  * concatenated array length is 0.
+ * TODO(lrn) Change length behavior to ECMAScript 5 specification (length
+ * is one more than the last array index to get a value assigned).
  */
 static uint32_t IterateArguments(Handle<JSArray> arguments,
                                  ArrayConcatVisitor* visitor) {
@@ -5646,16 +5736,23 @@
           IterateArrayAndPrototypeElements(array, visitor);
       // Total elements of array and its prototype chain can be more than
       // the array length, but ArrayConcat can only concatenate at most
-      // the array length number of elements.
-      visited_elements += (nof_elements > len) ? len : nof_elements;
+      // the array length number of elements. We use the length as an estimate
+      // for the actual number of elements added.
+      uint32_t added_elements = (nof_elements > len) ? len : nof_elements;
+      if (JSArray::kMaxElementCount - visited_elements < added_elements) {
+        visited_elements = JSArray::kMaxElementCount;
+      } else {
+        visited_elements += added_elements;
+      }
       if (visitor) visitor->increase_index_offset(len);
-
     } else {
       if (visitor) {
         visitor->visit(0, obj);
         visitor->increase_index_offset(1);
       }
-      visited_elements++;
+      if (visited_elements < JSArray::kMaxElementCount) {
+        visited_elements++;
+      }
     }
   }
   return visited_elements;
@@ -5665,6 +5762,8 @@
 /**
  * Array::concat implementation.
  * See ECMAScript 262, 15.4.4.4.
+ * TODO(lrn): Fix non-compliance for very large concatenations and update to
+ * following the ECMAScript 5 specification.
  */
 static Object* Runtime_ArrayConcat(Arguments args) {
   ASSERT(args.length() == 1);
@@ -5681,12 +5780,18 @@
   { AssertNoAllocation nogc;
     for (uint32_t i = 0; i < num_of_args; i++) {
       Object* obj = arguments->GetElement(i);
+      uint32_t length_estimate;
       if (obj->IsJSArray()) {
-        result_length +=
+        length_estimate =
             static_cast<uint32_t>(JSArray::cast(obj)->length()->Number());
       } else {
-        result_length++;
+        length_estimate = 1;
       }
+      if (JSObject::kMaxElementCount - result_length < length_estimate) {
+        result_length = JSObject::kMaxElementCount;
+        break;
+      }
+      result_length += length_estimate;
     }
   }
 
diff --git a/src/runtime.h b/src/runtime.h
index f13c424..b6542a6 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -61,6 +61,8 @@
   \
   F(IsConstructCall, 0, 1) \
   \
+  F(GetOwnProperty, 2, 1) \
+  \
   /* Utilities */ \
   F(GetCalledFunction, 0, 1) \
   F(GetFunctionDelegate, 1, 1) \
@@ -103,7 +105,7 @@
   F(NumberUnaryMinus, 1, 1) \
   \
   F(StringAdd, 2, 1) \
-  F(StringBuilderConcat, 2, 1) \
+  F(StringBuilderConcat, 3, 1) \
   \
   /* Bit operations */ \
   F(NumberOr, 2, 1) \
@@ -146,6 +148,7 @@
   \
   /* Strings */ \
   F(StringCharCodeAt, 2, 1) \
+  F(StringCharAt, 2, 1) \
   F(StringIndexOf, 3, 1) \
   F(StringLastIndexOf, 3, 1) \
   F(StringLocaleCompare, 2, 1) \
@@ -202,7 +205,7 @@
   \
   /* Eval */ \
   F(GlobalReceiver, 1, 1) \
-  F(ResolvePossiblyDirectEval, 2, 1) \
+  F(ResolvePossiblyDirectEval, 3, 2) \
   \
   F(SetProperty, -1 /* 3 or 4 */, 1) \
   F(IgnoreAttributesAndSetProperty, -1 /* 3 or 4 */, 1) \
diff --git a/src/runtime.js b/src/runtime.js
index 1b65fe5..ce2f197 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -114,30 +114,33 @@
 // ECMA-262, section 11.8.5, page 53. The 'ncr' parameter is used as
 // the result when either (or both) the operands are NaN.
 function COMPARE(x, ncr) {
-  // Fast case for numbers and strings.
-  if (IS_NUMBER(this) && IS_NUMBER(x)) {
-    return %NumberCompare(this, x, ncr);
-  }
-  if (IS_STRING(this) && IS_STRING(x)) {
-    return %StringCompare(this, x);
-  }
+  var left;
 
-  // If one of the operands is undefined, it will convert to NaN and
-  // thus the result should be as if one of the operands was NaN.
-  if (IS_UNDEFINED(this) || IS_UNDEFINED(x)) {
+  // Fast cases for string, numbers and undefined compares.
+  if (IS_STRING(this)) {
+    if (IS_STRING(x)) return %_StringCompare(this, x);
+    if (IS_UNDEFINED(x)) return ncr;
+    left = this;
+  } else if (IS_NUMBER(this)) {
+    if (IS_NUMBER(x)) return %NumberCompare(this, x, ncr);
+    if (IS_UNDEFINED(x)) return ncr;
+    left = this;
+  } else if (IS_UNDEFINED(this)) {
     return ncr;
+  } else {
+    if (IS_UNDEFINED(x)) return ncr;
+    left = %ToPrimitive(this, NUMBER_HINT);
   }
 
   // Default implementation.
-  var a = %ToPrimitive(this, NUMBER_HINT);
-  var b = %ToPrimitive(x, NUMBER_HINT);
-  if (IS_STRING(a) && IS_STRING(b)) {
-    return %StringCompare(a, b);
+  var right = %ToPrimitive(x, NUMBER_HINT);
+  if (IS_STRING(left) && IS_STRING(right)) {
+    return %_StringCompare(left, right);
   } else {
-    var a_number = %ToNumber(a);
-    var b_number = %ToNumber(b);
-    if (NUMBER_IS_NAN(a_number) || NUMBER_IS_NAN(b_number)) return ncr;
-    return %NumberCompare(a_number, b_number, ncr);
+    var left_number = %ToNumber(left);
+    var right_number = %ToNumber(right);
+    if (NUMBER_IS_NAN(left_number) || NUMBER_IS_NAN(right_number)) return ncr;
+    return %NumberCompare(left_number, right_number, ncr);
   }
 }
 
@@ -474,6 +477,17 @@
 }
 
 
+// Specialized version of String.charAt. It assumes string as
+// the receiver type and that the index is a number.
+function STRING_CHAR_AT(pos) {
+  var char_code = %_FastCharCodeAt(this, pos);
+  if (!%_IsSmi(char_code)) {
+    return %StringCharAt(this, pos);
+  }
+  return %CharFromCode(char_code);
+}
+
+
 /* -------------------------------------
    - - -   C o n v e r s i o n s   - - -
    -------------------------------------
diff --git a/src/scopes.cc b/src/scopes.cc
index a47d373..701e5e3 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -236,7 +236,7 @@
 
 Variable* Scope::DeclareGlobal(Handle<String> name) {
   ASSERT(is_global_scope());
-  return variables_.Declare(this, name, Variable::DYNAMIC, true,
+  return variables_.Declare(this, name, Variable::DYNAMIC_GLOBAL, true,
                             Variable::NORMAL);
 }
 
diff --git a/src/serialize.cc b/src/serialize.cc
index fe04252..db46f3a 100644
--- a/src/serialize.cc
+++ b/src/serialize.cc
@@ -918,7 +918,8 @@
 Serializer::Serializer(SnapshotByteSink* sink)
     : sink_(sink),
       current_root_index_(0),
-      external_reference_encoder_(NULL) {
+      external_reference_encoder_(NULL),
+      partial_(false) {
   for (int i = 0; i <= LAST_SPACE; i++) {
     fullness_[i] = 0;
   }
@@ -946,6 +947,16 @@
 }
 
 
+void Serializer::SerializePartial(Object** object) {
+  partial_ = true;
+  external_reference_encoder_ = new ExternalReferenceEncoder();
+  this->VisitPointer(object);
+  delete external_reference_encoder_;
+  external_reference_encoder_ = NULL;
+  SerializationAddressMapper::Zap();
+}
+
+
 void Serializer::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     if ((*current)->IsSmi()) {
@@ -961,11 +972,30 @@
 }
 
 
+int Serializer::RootIndex(HeapObject* heap_object) {
+  for (int i = 0; i < Heap::kRootListLength; i++) {
+    Object* root = Heap::roots_address()[i];
+    if (root == heap_object) return i;
+  }
+  return kInvalidRootIndex;
+}
+
+
 void Serializer::SerializeObject(
     Object* o,
     ReferenceRepresentation reference_representation) {
   CHECK(o->IsHeapObject());
   HeapObject* heap_object = HeapObject::cast(o);
+  if (partial_) {
+    int root_index = RootIndex(heap_object);
+    if (root_index != kInvalidRootIndex) {
+      sink_->Put(ROOT_SERIALIZATION, "RootSerialization");
+      sink_->PutInt(root_index, "root_index");
+      return;
+    }
+    // All the symbols that the snapshot needs should be in the root table.
+    ASSERT(!heap_object->IsSymbol());
+  }
   if (SerializationAddressMapper::IsMapped(heap_object)) {
     int space = SpaceOfAlreadySerializedObject(heap_object);
     int address = SerializationAddressMapper::MappedTo(heap_object);
diff --git a/src/serialize.h b/src/serialize.h
index 96bd751..b32f4e8 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -199,7 +199,8 @@
     SYNCHRONIZE = 36,
     START_NEW_PAGE_SERIALIZATION = 37,
     NATIVES_STRING_RESOURCE = 38,
-    // Free: 39-47.
+    ROOT_SERIALIZATION = 39,
+    // Free: 40-47.
     BACKREF_SERIALIZATION = 48,
     // One per space, must be kSpaceMask aligned.
     // Free: 57-63.
@@ -293,10 +294,17 @@
 class Serializer : public SerDes {
  public:
   explicit Serializer(SnapshotByteSink* sink);
-  // Serialize the current state of the heap. This operation destroys the
-  // heap contents.
+  // Serialize the current state of the heap.
   void Serialize();
+  // Serialize a single object and the objects reachable from it.
+  void SerializePartial(Object** obj);
   void VisitPointers(Object** start, Object** end);
+  // You can call this after serialization to find out how much space was used
+  // in each space.
+  int CurrentAllocationAddress(int space) {
+    if (SpaceIsLarge(space)) space = LO_SPACE;
+    return fullness_[space];
+  }
 
   static void Enable() {
     if (!serialization_enabled_) {
@@ -366,13 +374,11 @@
   // once the map has been used for the serialization address.
   static int SpaceOfAlreadySerializedObject(HeapObject* object);
   int Allocate(int space, int size, bool* new_page_started);
-  int CurrentAllocationAddress(int space) {
-    if (SpaceIsLarge(space)) space = LO_SPACE;
-    return fullness_[space];
-  }
   int EncodeExternalReference(Address addr) {
     return external_reference_encoder_->Encode(addr);
   }
+  int RootIndex(HeapObject* heap_object);
+  static const int kInvalidRootIndex = -1;
 
   // Keep track of the fullness of each space in order to generate
   // relative addresses for back references.  Large objects are
@@ -382,6 +388,7 @@
   SnapshotByteSink* sink_;
   int current_root_index_;
   ExternalReferenceEncoder* external_reference_encoder_;
+  bool partial_;
   static bool serialization_enabled_;
   // Did we already make use of the fact that serialization was not enabled?
   static bool too_late_to_enable_now_;
diff --git a/src/spaces.cc b/src/spaces.cc
index f4d0cb0..cd09398 100644
--- a/src/spaces.cc
+++ b/src/spaces.cc
@@ -92,6 +92,7 @@
   cur_addr_ = cur_page->ObjectAreaStart();
   cur_limit_ = (cur_page == end_page_) ? end_addr_ : cur_page->AllocationTop();
 
+  if (cur_addr_ == end_addr_) return false;
   ASSERT(cur_addr_ < cur_limit_);
 #ifdef DEBUG
   Verify();
@@ -1735,7 +1736,8 @@
     Memory::Address_at(start + i) = kZapValue;
   }
 #endif
-  ASSERT(!FLAG_always_compact);  // We only use the freelists with mark-sweep.
+  // We only use the freelists with mark-sweep.
+  ASSERT(!MarkCompactCollector::IsCompacting());
   FreeListNode* node = FreeListNode::FromAddress(start);
   node->set_size(object_size_);
   node->set_next(head_);
@@ -1821,6 +1823,50 @@
 }
 
 
+bool NewSpace::ReserveSpace(int bytes) {
+  // We can't reliably unpack a partial snapshot that needs more new space
+  // space than the minimum NewSpace size.
+  ASSERT(bytes <= InitialCapacity());
+  Address limit = allocation_info_.limit;
+  Address top = allocation_info_.top;
+  return limit - top >= bytes;
+}
+
+
+bool PagedSpace::ReserveSpace(int bytes) {
+  Address limit = allocation_info_.limit;
+  Address top = allocation_info_.top;
+  if (limit - top >= bytes) return true;
+
+  // There wasn't enough space in the current page.  Lets put the rest
+  // of the page on the free list and start a fresh page.
+  PutRestOfCurrentPageOnFreeList(TopPageOf(allocation_info_));
+
+  Page* reserved_page = TopPageOf(allocation_info_);
+  int bytes_left_to_reserve = bytes;
+  while (bytes_left_to_reserve > 0) {
+    if (!reserved_page->next_page()->is_valid()) {
+      if (Heap::OldGenerationAllocationLimitReached()) return false;
+      Expand(reserved_page);
+    }
+    bytes_left_to_reserve -= Page::kPageSize;
+    reserved_page = reserved_page->next_page();
+    if (!reserved_page->is_valid()) return false;
+  }
+  ASSERT(TopPageOf(allocation_info_)->next_page()->is_valid());
+  SetAllocationInfo(&allocation_info_,
+                    TopPageOf(allocation_info_)->next_page());
+  return true;
+}
+
+
+// You have to call this last, since the implementation from PagedSpace
+// doesn't know that memory was 'promised' to large object space.
+bool LargeObjectSpace::ReserveSpace(int bytes) {
+  return Heap::OldGenerationSpaceAvailable() >= bytes;
+}
+
+
 // Slow case for normal allocation.  Try in order: (1) allocate in the next
 // page in the space, (2) allocate off the space's free list, (3) expand the
 // space, (4) fail.
@@ -1864,19 +1910,37 @@
 }
 
 
-// Add the block at the top of the page to the space's free list, set the
-// allocation info to the next page (assumed to be one), and allocate
-// linearly there.
-HeapObject* OldSpace::AllocateInNextPage(Page* current_page,
-                                         int size_in_bytes) {
-  ASSERT(current_page->next_page()->is_valid());
-  // Add the block at the top of this page to the free list.
+void OldSpace::PutRestOfCurrentPageOnFreeList(Page* current_page) {
   int free_size =
       static_cast<int>(current_page->ObjectAreaEnd() - allocation_info_.top);
   if (free_size > 0) {
     int wasted_bytes = free_list_.Free(allocation_info_.top, free_size);
     accounting_stats_.WasteBytes(wasted_bytes);
   }
+}
+
+
+void FixedSpace::PutRestOfCurrentPageOnFreeList(Page* current_page) {
+  int free_size =
+      static_cast<int>(current_page->ObjectAreaEnd() - allocation_info_.top);
+  // In the fixed space free list all the free list items have the right size.
+  // We use up the rest of the page while preserving this invariant.
+  while (free_size >= object_size_in_bytes_) {
+    free_list_.Free(allocation_info_.top);
+    allocation_info_.top += object_size_in_bytes_;
+    free_size -= object_size_in_bytes_;
+    accounting_stats_.WasteBytes(object_size_in_bytes_);
+  }
+}
+
+
+// Add the block at the top of the page to the space's free list, set the
+// allocation info to the next page (assumed to be one), and allocate
+// linearly there.
+HeapObject* OldSpace::AllocateInNextPage(Page* current_page,
+                                         int size_in_bytes) {
+  ASSERT(current_page->next_page()->is_valid());
+  PutRestOfCurrentPageOnFreeList(current_page);
   SetAllocationInfo(&allocation_info_, current_page->next_page());
   return AllocateLinearly(&allocation_info_, size_in_bytes);
 }
diff --git a/src/spaces.h b/src/spaces.h
index faeafaf..4786fb4 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -305,6 +305,14 @@
   virtual void Print() = 0;
 #endif
 
+  // After calling this we can allocate a certain number of bytes using only
+  // linear allocation (with a LinearAllocationScope and an AlwaysAllocateScope)
+  // without using freelists or causing a GC.  This is used by partial
+  // snapshots.  It returns true of space was reserved or false if a GC is
+  // needed.  For paged spaces the space requested must include the space wasted
+  // at the end of each when allocating linearly.
+  virtual bool ReserveSpace(int bytes) = 0;
+
  private:
   AllocationSpace id_;
   Executability executable_;
@@ -887,6 +895,10 @@
   // collection.
   inline Object* MCAllocateRaw(int size_in_bytes);
 
+  virtual bool ReserveSpace(int bytes);
+
+  // Used by ReserveSpace.
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page) = 0;
 
   // ---------------------------------------------------------------------------
   // Mark-compact collection support functions
@@ -993,6 +1005,9 @@
   HeapObject* SlowMCAllocateRaw(int size_in_bytes);
 
 #ifdef DEBUG
+  // Returns the number of total pages in this space.
+  int CountTotalPages();
+
   void DoPrintRSet(const char* space_name);
 #endif
  private:
@@ -1002,11 +1017,6 @@
   // Returns a pointer to the page of the relocation pointer.
   Page* MCRelocationTopPage() { return TopPageOf(mc_forwarding_info_); }
 
-#ifdef DEBUG
-  // Returns the number of total pages in this space.
-  int CountTotalPages();
-#endif
-
   friend class PageIterator;
 };
 
@@ -1117,13 +1127,18 @@
     return static_cast<int>(addr - low());
   }
 
-  // If we don't have this here then SemiSpace will be abstract.  However
-  // it should never be called.
+  // If we don't have these here then SemiSpace will be abstract.  However
+  // they should never be called.
   virtual int Size() {
     UNREACHABLE();
     return 0;
   }
 
+  virtual bool ReserveSpace(int bytes) {
+    UNREACHABLE();
+    return false;
+  }
+
   bool is_committed() { return committed_; }
   bool Commit();
   bool Uncommit();
@@ -1347,6 +1362,8 @@
   bool ToSpaceContains(Address a) { return to_space_.Contains(a); }
   bool FromSpaceContains(Address a) { return from_space_.Contains(a); }
 
+  virtual bool ReserveSpace(int bytes);
+
 #ifdef ENABLE_HEAP_PROTECTION
   // Protect/unprotect the space by marking it read-only/writable.
   virtual void Protect();
@@ -1633,6 +1650,8 @@
   // collection.
   virtual void MCCommitRelocationInfo();
 
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page);
+
 #ifdef DEBUG
   // Reports statistics for the space
   void ReportStatistics();
@@ -1694,6 +1713,8 @@
   // collection.
   virtual void MCCommitRelocationInfo();
 
+  virtual void PutRestOfCurrentPageOnFreeList(Page* current_page);
+
 #ifdef DEBUG
   // Reports statistic info of the space
   void ReportStatistics();
@@ -1710,6 +1731,10 @@
   // the page after current_page (there is assumed to be one).
   HeapObject* AllocateInNextPage(Page* current_page, int size_in_bytes);
 
+  void ResetFreeList() {
+    free_list_.Reset();
+  }
+
  private:
   // The size of objects in this space.
   int object_size_in_bytes_;
@@ -1740,12 +1765,81 @@
   // Constants.
   static const int kMaxMapPageIndex = (1 << MapWord::kMapPageIndexBits) - 1;
 
+  // Are map pointers encodable into map word?
+  bool MapPointersEncodable() {
+    if (!FLAG_use_big_map_space) {
+      ASSERT(CountTotalPages() <= kMaxMapPageIndex);
+      return true;
+    }
+    int n_of_pages = Capacity() / Page::kObjectAreaSize;
+    ASSERT(n_of_pages == CountTotalPages());
+    return n_of_pages <= kMaxMapPageIndex;
+  }
+
+  // Should be called after forced sweep to find out if map space needs
+  // compaction.
+  bool NeedsCompaction(int live_maps) {
+    return !MapPointersEncodable() && live_maps <= kCompactionThreshold;
+  }
+
+  Address TopAfterCompaction(int live_maps) {
+    ASSERT(NeedsCompaction(live_maps));
+
+    int pages_left = live_maps / kMapsPerPage;
+    PageIterator it(this, PageIterator::ALL_PAGES);
+    while (pages_left-- > 0) {
+      ASSERT(it.has_next());
+      it.next()->ClearRSet();
+    }
+    ASSERT(it.has_next());
+    Page* top_page = it.next();
+    top_page->ClearRSet();
+    ASSERT(top_page->is_valid());
+
+    int offset = live_maps % kMapsPerPage * Map::kSize;
+    Address top = top_page->ObjectAreaStart() + offset;
+    ASSERT(top < top_page->ObjectAreaEnd());
+    ASSERT(Contains(top));
+
+    return top;
+  }
+
+  void FinishCompaction(Address new_top, int live_maps) {
+    Page* top_page = Page::FromAddress(new_top);
+    ASSERT(top_page->is_valid());
+
+    SetAllocationInfo(&allocation_info_, top_page);
+    allocation_info_.top = new_top;
+
+    int new_size = live_maps * Map::kSize;
+    accounting_stats_.DeallocateBytes(accounting_stats_.Size());
+    accounting_stats_.AllocateBytes(new_size);
+
+#ifdef DEBUG
+    if (FLAG_enable_slow_asserts) {
+      int actual_size = 0;
+      for (Page* p = first_page_; p != top_page; p = p->next_page())
+        actual_size += kMapsPerPage * Map::kSize;
+      actual_size += (new_top - top_page->ObjectAreaStart());
+      ASSERT(accounting_stats_.Size() == actual_size);
+    }
+#endif
+
+    Shrink();
+    ResetFreeList();
+  }
+
  protected:
 #ifdef DEBUG
   virtual void VerifyObject(HeapObject* obj);
 #endif
 
  private:
+  static const int kMapsPerPage = Page::kObjectAreaSize / Map::kSize;
+
+  // Do map space compaction if there is a page gap.
+  static const int kCompactionThreshold = kMapsPerPage * (kMaxMapPageIndex - 1);
+
   // An array of page start address in a map space.
   Address page_addresses_[kMaxMapPageIndex + 1];
 
@@ -1890,6 +1984,11 @@
   // Checks whether the space is empty.
   bool IsEmpty() { return first_chunk_ == NULL; }
 
+  // See the comments for ReserveSpace in the Space class.  This has to be
+  // called after ReserveSpace has been called on the paged spaces, since they
+  // may use some memory, leaving less for large objects.
+  virtual bool ReserveSpace(int bytes);
+
 #ifdef ENABLE_HEAP_PROTECTION
   // Protect/unprotect the space by marking it read-only/writable.
   void Protect();
diff --git a/src/string.js b/src/string.js
index 4f9957a..ed938ec 100644
--- a/src/string.js
+++ b/src/string.js
@@ -87,12 +87,14 @@
 
 // ECMA-262, section 15.5.4.6
 function StringConcat() {
-  var len = %_ArgumentsLength();
-  var parts = new $Array(len + 1);
-  parts[0] = ToString(this);
-  for (var i = 0; i < len; i++)
-    parts[i + 1] = ToString(%_Arguments(i));
-  return parts.join('');
+  var len = %_ArgumentsLength() + 1;
+  var parts = new $Array(len);
+  parts[0] = IS_STRING(this) ? this : ToString(this);
+  for (var i = 1; i < len; i++) {
+    var part = %_Arguments(i - 1);
+    parts[i] = IS_STRING(part) ? part : ToString(part);
+  }
+  return %StringBuilderConcat(parts, len, "");
 }
 
 // Match ES3 and Safari
@@ -180,7 +182,7 @@
     }
     return %CharFromCode(char_code);
   }
-  return %SubString(string, start, end);
+  return %_SubString(string, start, end);
 }
 
 
@@ -194,7 +196,7 @@
 
 // ECMA-262, section 15.5.4.11
 function StringReplace(search, replace) {
-  var subject = ToString(this);
+  var subject = IS_STRING(this) ? this : ToString(this);
 
   // Delegate to one of the regular expression variants if necessary.
   if (IS_REGEXP(search)) {
@@ -207,7 +209,7 @@
   }
 
   // Convert the search argument to a string and search for it.
-  search = ToString(search);
+  search = IS_STRING(search) ? search : ToString(search);
   var start = %StringIndexOf(subject, search, 0);
   if (start < 0) return subject;
   var end = start + search.length;
@@ -222,7 +224,8 @@
   } else {
     reusableMatchInfo[CAPTURE0] = start;
     reusableMatchInfo[CAPTURE1] = end;
-    ExpandReplacement(ToString(replace), subject, reusableMatchInfo, builder);
+    if (!IS_STRING(replace)) replace = ToString(replace);
+    ExpandReplacement(replace, subject, reusableMatchInfo, builder);
   }
 
   // suffix
@@ -505,7 +508,7 @@
 // ECMA-262 section 15.5.4.14
 function StringSplit(separator, limit) {
   var subject = ToString(this);
-  limit = (limit === void 0) ? 0xffffffff : ToUint32(limit);
+  limit = (IS_UNDEFINED(limit)) ? 0xffffffff : TO_UINT32(limit);
   if (limit === 0) return [];
 
   // ECMA-262 says that if separator is undefined, the result should
@@ -604,22 +607,30 @@
 
 // ECMA-262 section 15.5.4.15
 function StringSubstring(start, end) {
-  var s = ToString(this);
+  var s = this;
+  if (!IS_STRING(s)) s = ToString(s);
   var s_len = s.length;
+
   var start_i = TO_INTEGER(start);
+  if (start_i < 0) {
+    start_i = 0;
+  } else if (start_i > s_len) {
+    start_i = s_len;
+  }
+
   var end_i = s_len;
-  if (!IS_UNDEFINED(end))
+  if (!IS_UNDEFINED(end)) {
     end_i = TO_INTEGER(end);
-
-  if (start_i < 0) start_i = 0;
-  if (start_i > s_len) start_i = s_len;
-  if (end_i < 0) end_i = 0;
-  if (end_i > s_len) end_i = s_len;
-
-  if (start_i > end_i) {
-    var tmp = end_i;
-    end_i = start_i;
-    start_i = tmp;
+    if (end_i > s_len) {
+      end_i = s_len;
+    } else {
+      if (end_i < 0) end_i = 0;
+      if (start_i > end_i) {
+        var tmp = end_i;
+        end_i = start_i;
+        start_i = tmp;
+      }
+    }
   }
 
   return SubString(s, start_i, end_i);
@@ -790,21 +801,14 @@
 }
 
 
-// StringBuilder support.
-
-function StringBuilder() {
-  this.elements = new $Array();
-}
-
-
+// ReplaceResultBuilder support.
 function ReplaceResultBuilder(str) {
   this.elements = new $Array();
   this.special_string = str;
 }
 
 
-ReplaceResultBuilder.prototype.add =
-StringBuilder.prototype.add = function(str) {
+ReplaceResultBuilder.prototype.add = function(str) {
   if (!IS_STRING(str)) str = ToString(str);
   if (str.length > 0) {
     var elements = this.elements;
@@ -828,13 +832,9 @@
 }
 
 
-StringBuilder.prototype.generate = function() {
-  return %StringBuilderConcat(this.elements, "");
-}
-
-
 ReplaceResultBuilder.prototype.generate = function() {
-  return %StringBuilderConcat(this.elements, this.special_string);
+  var elements = this.elements;
+  return %StringBuilderConcat(elements, elements.length, this.special_string);
 }
 
 
diff --git a/src/utils.cc b/src/utils.cc
index 08ee16f..374385b 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -40,6 +40,7 @@
 // Implementation is from "Hacker's Delight" by Henry S. Warren, Jr.,
 // figure 3-3, page 48, where the function is called clp2.
 uint32_t RoundUpToPowerOf2(uint32_t x) {
+  ASSERT(x <= 0x80000000u);
   x = x - 1;
   x = x | (x >> 1);
   x = x | (x >> 2);
diff --git a/src/v8-counters.h b/src/v8-counters.h
index 158824d..fb1e926 100644
--- a/src/v8-counters.h
+++ b/src/v8-counters.h
@@ -153,7 +153,13 @@
   SC(generic_binary_stub_calls, V8.GenericBinaryStubCalls)          \
   SC(generic_binary_stub_calls_regs, V8.GenericBinaryStubCallsRegs) \
   SC(string_add_runtime, V8.StringAddRuntime)                       \
-  SC(string_add_native, V8.StringAddNative)
+  SC(string_add_native, V8.StringAddNative)                         \
+  SC(sub_string_runtime, V8.SubStringRuntime)                       \
+  SC(sub_string_native, V8.SubStringNative)                         \
+  SC(string_compare_native, V8.StringCompareNative)                 \
+  SC(string_compare_runtime, V8.StringCompareRuntime)               \
+  SC(regexp_entry_runtime, V8.RegExpEntryRuntime)                   \
+  SC(regexp_entry_native, V8.RegExpEntryNative)
 
 // This file contains all the v8 counters that are in use.
 class Counters : AllStatic {
diff --git a/src/v8natives.js b/src/v8natives.js
index a664095..700b9e4 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -305,6 +305,22 @@
   return IsAccessorDescriptor(desc) && IsDataDescriptor(desc);
 }
 
+// ES5 8.10.4
+function FromPropertyDescriptor(desc) {
+  if(IS_UNDEFINED(desc)) return desc;
+  var obj = new $Object();
+  if (IsDataDescriptor(desc)) {
+    obj.value = desc.getValue();
+    obj.writable = desc.isWritable();
+  }
+  if (IsAccessorDescriptor(desc)) {
+    obj.get = desc.getGet();
+    obj.set = desc.getSet();
+  }
+  obj.enumerable = desc.isEnumerable();
+  obj.configurable = desc.isConfigurable();
+  return obj;
+}
 
 // ES5 8.10.5.
 function ToPropertyDescriptor(obj) {
@@ -433,6 +449,33 @@
 }
 
 
+// ES5 section 8.12.1.
+function GetOwnProperty(obj, p) {
+  var desc = new PropertyDescriptor();
+  
+  // An array with:
+  //  obj is a data property [false, value, Writeable, Enumerable, Configurable]
+  //  obj is an accessor [true, Get, Set, Enumerable, Configurable]
+  var props = %GetOwnProperty(ToObject(obj), ToString(p));
+
+  if (IS_UNDEFINED(props))
+    return void 0;
+
+  // This is an accessor
+  if (props[0]) {
+    desc.setGet(props[1]);
+    desc.setSet(props[2]);
+  } else {
+    desc.setValue(props[1]);
+    desc.setWritable(props[2]);
+  }
+  desc.setEnumerable(props[3]);
+  desc.setConfigurable(props[4]);
+
+  return desc;
+}
+
+
 // ES5 8.12.9.  This version cannot cope with the property p already
 // being present on obj.
 function DefineOwnProperty(obj, p, desc, should_throw) {
@@ -448,6 +491,25 @@
 }
 
 
+// ES5 section 15.2.3.2.
+function ObjectGetPrototypeOf(obj) {
+ if (!IS_OBJECT(obj) && !IS_FUNCTION(obj)) {
+   throw MakeTypeError("object_get_prototype_non_object", [obj]);
+ }
+ return obj.__proto__;
+}
+
+
+// ES5 section 15.2.3.3 
+function ObjectGetOwnPropertyDescriptor(obj, p) {
+  if (!IS_OBJECT(obj) && !IS_FUNCTION(obj)) {
+    throw MakeTypeError("object_get_prototype_non_object", [obj]);
+  }
+  var desc = GetOwnProperty(obj, p);
+  return FromPropertyDescriptor(desc);
+}
+
+
 // ES5 section 15.2.3.5.
 function ObjectCreate(proto, properties) {
   if (!IS_OBJECT(proto) && !IS_NULL(proto)) {
@@ -512,7 +574,9 @@
   ));
   InstallFunctions($Object, DONT_ENUM, $Array(
     "keys", ObjectKeys,
-    "create", ObjectCreate
+    "create", ObjectCreate,
+    "getPrototypeOf", ObjectGetPrototypeOf,
+    "getOwnPropertyDescriptor", ObjectGetOwnPropertyDescriptor
   ));
 }
 
diff --git a/src/version.cc b/src/version.cc
index 5e3cd9c..b636921 100644
--- a/src/version.cc
+++ b/src/version.cc
@@ -34,8 +34,8 @@
 // cannot be changed without changing the SCons build script.
 #define MAJOR_VERSION     2
 #define MINOR_VERSION     0
-#define BUILD_NUMBER      5
-#define PATCH_LEVEL       5
+#define BUILD_NUMBER      6
+#define PATCH_LEVEL       0
 #define CANDIDATE_VERSION false
 
 // Define SONAME to have the SCons build the put a specific SONAME into the
diff --git a/src/x64/codegen-x64-inl.h b/src/x64/codegen-x64-inl.h
index 6869fc9..60e9ab0 100644
--- a/src/x64/codegen-x64-inl.h
+++ b/src/x64/codegen-x64-inl.h
@@ -39,16 +39,6 @@
 void DeferredCode::Jump() { __ jmp(&entry_label_); }
 void DeferredCode::Branch(Condition cc) { __ j(cc, &entry_label_); }
 
-
-void CodeGenerator::GenerateMathSin(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(SIN, args);
-}
-
-
-void CodeGenerator::GenerateMathCos(ZoneList<Expression*>* args) {
-  GenerateFastMathOp(COS, args);
-}
-
 #undef __
 
 } }  // namespace v8::internal
diff --git a/src/x64/codegen-x64.cc b/src/x64/codegen-x64.cc
index 85ccb67..e912bbc 100644
--- a/src/x64/codegen-x64.cc
+++ b/src/x64/codegen-x64.cc
@@ -326,12 +326,19 @@
     function_return_is_shadowed_ = false;
 
     // Allocate the local context if needed.
-    if (scope_->num_heap_slots() > 0) {
+    int heap_slots = scope_->num_heap_slots();
+    if (heap_slots > 0) {
       Comment cmnt(masm_, "[ allocate local context");
       // Allocate local context.
       // Get outer context and create a new context based on it.
       frame_->PushFunction();
-      Result context = frame_->CallRuntime(Runtime::kNewContext, 1);
+      Result context;
+      if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+        FastNewContextStub stub(heap_slots);
+        context = frame_->CallStub(&stub, 1);
+      } else {
+        context = frame_->CallRuntime(Runtime::kNewContext, 1);
+      }
 
       // Update context local.
       frame_->SaveContextRegister();
@@ -393,6 +400,12 @@
       StoreArgumentsObject(true);
     }
 
+    // Initialize ThisFunction reference if present.
+    if (scope_->is_function_scope() && scope_->function() != NULL) {
+      frame_->Push(Factory::the_hole_value());
+      StoreToSlot(scope_->function()->slot(), NOT_CONST_INIT);
+    }
+
     // Generate code to 'execute' declarations and initialize functions
     // (source elements). In case of an illegal redeclaration we need to
     // handle that instead of processing the declarations.
@@ -1865,13 +1878,9 @@
   frame_->EmitPush(rax);
 
   // Store the caught exception in the catch variable.
-  { Reference ref(this, node->catch_var());
-    ASSERT(ref.is_slot());
-    // Load the exception to the top of the stack.  Here we make use of the
-    // convenient property that it doesn't matter whether a value is
-    // immediately on top of or underneath a zero-sized reference.
-    ref.SetValue(NOT_CONST_INIT);
-  }
+  Variable* catch_var = node->catch_var()->var();
+  ASSERT(catch_var != NULL && catch_var->slot() != NULL);
+  StoreToSlot(catch_var->slot(), NOT_CONST_INIT);
 
   // Remove the exception from the stack.
   frame_->Drop();
@@ -2196,19 +2205,28 @@
 
 
 void CodeGenerator::InstantiateBoilerplate(Handle<JSFunction> boilerplate) {
-  // Call the runtime to instantiate the function boilerplate object.
+  ASSERT(boilerplate->IsBoilerplate());
+
   // The inevitable call will sync frame elements to memory anyway, so
   // we do it eagerly to allow us to push the arguments directly into
   // place.
-  ASSERT(boilerplate->IsBoilerplate());
   frame_->SyncRange(0, frame_->element_count() - 1);
 
-  // Create a new closure.
-  frame_->EmitPush(rsi);
-  __ movq(kScratchRegister, boilerplate, RelocInfo::EMBEDDED_OBJECT);
-  frame_->EmitPush(kScratchRegister);
-  Result result = frame_->CallRuntime(Runtime::kNewClosure, 2);
-  frame_->Push(&result);
+  // Use the fast case closure allocation code that allocates in new
+  // space for nested functions that don't need literals cloning.
+  if (scope()->is_function_scope() && boilerplate->NumberOfLiterals() == 0) {
+    FastNewClosureStub stub;
+    frame_->Push(boilerplate);
+    Result answer = frame_->CallStub(&stub, 1);
+    frame_->Push(&answer);
+  } else {
+    // Call the runtime to instantiate the function boilerplate
+    // object.
+    frame_->EmitPush(rsi);
+    frame_->EmitPush(boilerplate);
+    Result result = frame_->CallRuntime(Runtime::kNewClosure, 2);
+    frame_->Push(&result);
+  }
 }
 
 
@@ -2362,46 +2380,10 @@
 }
 
 
-// Materialize the object literal 'node' in the literals array
-// 'literals' of the function.  Leave the object boilerplate in
-// 'boilerplate'.
-class DeferredObjectLiteral: public DeferredCode {
- public:
-  DeferredObjectLiteral(Register boilerplate,
-                        Register literals,
-                        ObjectLiteral* node)
-      : boilerplate_(boilerplate), literals_(literals), node_(node) {
-    set_comment("[ DeferredObjectLiteral");
-  }
-
-  void Generate();
-
- private:
-  Register boilerplate_;
-  Register literals_;
-  ObjectLiteral* node_;
-};
-
-
-void DeferredObjectLiteral::Generate() {
-  // Since the entry is undefined we call the runtime system to
-  // compute the literal.
-  // Literal array (0).
-  __ push(literals_);
-  // Literal index (1).
-  __ Push(Smi::FromInt(node_->literal_index()));
-  // Constant properties (2).
-  __ Push(node_->constant_properties());
-  __ CallRuntime(Runtime::kCreateObjectLiteralBoilerplate, 3);
-  if (!boilerplate_.is(rax)) __ movq(boilerplate_, rax);
-}
-
-
 void CodeGenerator::VisitObjectLiteral(ObjectLiteral* node) {
   Comment cmnt(masm_, "[ ObjectLiteral");
 
-  // Retrieve the literals array and check the allocated entry.  Begin
-  // with a writable copy of the function of this activation in a
+  // Load a writable copy of the function of this activation in a
   // register.
   frame_->PushFunction();
   Result literals = frame_->Pop();
@@ -2411,32 +2393,18 @@
   // Load the literals array of the function.
   __ movq(literals.reg(),
           FieldOperand(literals.reg(), JSFunction::kLiteralsOffset));
-
-  // Load the literal at the ast saved index.
-  Result boilerplate = allocator_->Allocate();
-  ASSERT(boilerplate.is_valid());
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ movq(boilerplate.reg(), FieldOperand(literals.reg(), literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code passing the literals array.
-  DeferredObjectLiteral* deferred =
-      new DeferredObjectLiteral(boilerplate.reg(), literals.reg(), node);
-  __ CompareRoot(boilerplate.reg(), Heap::kUndefinedValueRootIndex);
-  deferred->Branch(equal);
-  deferred->BindExit();
-  literals.Unuse();
-
-  // Push the boilerplate object.
-  frame_->Push(&boilerplate);
-  // Clone the boilerplate object.
-  Runtime::FunctionId clone_function_id = Runtime::kCloneLiteralBoilerplate;
-  if (node->depth() == 1) {
-    clone_function_id = Runtime::kCloneShallowLiteralBoilerplate;
+  // Literal array.
+  frame_->Push(&literals);
+  // Literal index.
+  frame_->Push(Smi::FromInt(node->literal_index()));
+  // Constant properties.
+  frame_->Push(node->constant_properties());
+  Result clone;
+  if (node->depth() > 1) {
+    clone = frame_->CallRuntime(Runtime::kCreateObjectLiteral, 3);
+  } else {
+    clone = frame_->CallRuntime(Runtime::kCreateObjectLiteralShallow, 3);
   }
-  Result clone = frame_->CallRuntime(clone_function_id, 1);
-  // Push the newly cloned literal object as the result.
   frame_->Push(&clone);
 
   for (int i = 0; i < node->properties()->length(); i++) {
@@ -2496,45 +2464,10 @@
 }
 
 
-// Materialize the array literal 'node' in the literals array 'literals'
-// of the function.  Leave the array boilerplate in 'boilerplate'.
-class DeferredArrayLiteral: public DeferredCode {
- public:
-  DeferredArrayLiteral(Register boilerplate,
-                       Register literals,
-                       ArrayLiteral* node)
-      : boilerplate_(boilerplate), literals_(literals), node_(node) {
-    set_comment("[ DeferredArrayLiteral");
-  }
-
-  void Generate();
-
- private:
-  Register boilerplate_;
-  Register literals_;
-  ArrayLiteral* node_;
-};
-
-
-void DeferredArrayLiteral::Generate() {
-  // Since the entry is undefined we call the runtime system to
-  // compute the literal.
-  // Literal array (0).
-  __ push(literals_);
-  // Literal index (1).
-  __ Push(Smi::FromInt(node_->literal_index()));
-  // Constant properties (2).
-  __ Push(node_->literals());
-  __ CallRuntime(Runtime::kCreateArrayLiteralBoilerplate, 3);
-  if (!boilerplate_.is(rax)) __ movq(boilerplate_, rax);
-}
-
-
 void CodeGenerator::VisitArrayLiteral(ArrayLiteral* node) {
   Comment cmnt(masm_, "[ ArrayLiteral");
 
-  // Retrieve the literals array and check the allocated entry.  Begin
-  // with a writable copy of the function of this activation in a
+  // Load a writable copy of the function of this activation in a
   // register.
   frame_->PushFunction();
   Result literals = frame_->Pop();
@@ -2544,32 +2477,18 @@
   // Load the literals array of the function.
   __ movq(literals.reg(),
           FieldOperand(literals.reg(), JSFunction::kLiteralsOffset));
-
-  // Load the literal at the ast saved index.
-  Result boilerplate = allocator_->Allocate();
-  ASSERT(boilerplate.is_valid());
-  int literal_offset =
-      FixedArray::kHeaderSize + node->literal_index() * kPointerSize;
-  __ movq(boilerplate.reg(), FieldOperand(literals.reg(), literal_offset));
-
-  // Check whether we need to materialize the object literal boilerplate.
-  // If so, jump to the deferred code passing the literals array.
-  DeferredArrayLiteral* deferred =
-      new DeferredArrayLiteral(boilerplate.reg(), literals.reg(), node);
-  __ CompareRoot(boilerplate.reg(), Heap::kUndefinedValueRootIndex);
-  deferred->Branch(equal);
-  deferred->BindExit();
-  literals.Unuse();
-
-  // Push the resulting array literal boilerplate on the stack.
-  frame_->Push(&boilerplate);
-  // Clone the boilerplate object.
-  Runtime::FunctionId clone_function_id = Runtime::kCloneLiteralBoilerplate;
-  if (node->depth() == 1) {
-    clone_function_id = Runtime::kCloneShallowLiteralBoilerplate;
+  // Literal array.
+  frame_->Push(&literals);
+  // Literal index.
+  frame_->Push(Smi::FromInt(node->literal_index()));
+  // Constant elements.
+  frame_->Push(node->constant_elements());
+  Result clone;
+  if (node->depth() > 1) {
+    clone = frame_->CallRuntime(Runtime::kCreateArrayLiteral, 3);
+  } else {
+    clone = frame_->CallRuntime(Runtime::kCreateArrayLiteralShallow, 3);
   }
-  Result clone = frame_->CallRuntime(clone_function_id, 1);
-  // Push the newly cloned literal object as the result.
   frame_->Push(&clone);
 
   // Generate code to set the elements in the array that are not
@@ -2770,23 +2689,19 @@
       frame_->Push(Factory::undefined_value());
     }
 
+    // Push the receiver.
+    frame_->PushParameterAt(-1);
+
     // Resolve the call.
     Result result =
-        frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 2);
+        frame_->CallRuntime(Runtime::kResolvePossiblyDirectEval, 3);
 
-    // Touch up the stack with the right values for the function and the
-    // receiver.  Use a scratch register to avoid destroying the result.
-    Result scratch = allocator_->Allocate();
-    ASSERT(scratch.is_valid());
-    __ movq(scratch.reg(),
-            FieldOperand(result.reg(), FixedArray::OffsetOfElementAt(0)));
-    frame_->SetElementAt(arg_count + 1, &scratch);
-
-    // We can reuse the result register now.
-    frame_->Spill(result.reg());
-    __ movq(result.reg(),
-            FieldOperand(result.reg(), FixedArray::OffsetOfElementAt(1)));
-    frame_->SetElementAt(arg_count, &result);
+    // The runtime call returns a pair of values in rax (function) and
+    // rdx (receiver). Touch up the stack with the right values.
+    Result receiver = allocator_->Allocate(rdx);
+    frame_->SetElementAt(arg_count + 1, &result);
+    frame_->SetElementAt(arg_count, &receiver);
+    receiver.Unuse();
 
     // Call the function.
     CodeForSourcePosition(node->position());
@@ -3109,7 +3024,7 @@
         bool overwrite =
           (node->expression()->AsBinaryOperation() != NULL &&
            node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
-        UnarySubStub stub(overwrite);
+        GenericUnaryOpStub stub(Token::SUB, overwrite);
         // TODO(1222589): remove dependency of TOS being cached inside stub
         Result operand = frame_->Pop();
         Result answer = frame_->CallStub(&stub, &operand);
@@ -3979,69 +3894,16 @@
 }
 
 
-void CodeGenerator::GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args) {
-  JumpTarget done;
-  JumpTarget call_runtime;
-  ASSERT(args->length() == 1);
+void CodeGenerator::GenerateRegExpExec(ZoneList<Expression*>* args) {
+  ASSERT_EQ(args->length(), 4);
 
-  // Load number and duplicate it.
+  // Load the arguments on the stack and call the runtime system.
   Load(args->at(0));
-  frame_->Dup();
-
-  // Get the number into an unaliased register and load it onto the
-  // floating point stack still leaving one copy on the frame.
-  Result number = frame_->Pop();
-  number.ToRegister();
-  frame_->Spill(number.reg());
-  FloatingPointHelper::LoadFloatOperand(masm_, number.reg());
-  number.Unuse();
-
-  // Perform the operation on the number.
-  switch (op) {
-    case SIN:
-      __ fsin();
-      break;
-    case COS:
-      __ fcos();
-      break;
-  }
-
-  // Go slow case if argument to operation is out of range.
-  Result eax_reg = allocator()->Allocate(rax);
-  ASSERT(eax_reg.is_valid());
-  __ fnstsw_ax();
-  __ testl(rax, Immediate(0x0400));  // Bit 10 is condition flag C2.
-  eax_reg.Unuse();
-  call_runtime.Branch(not_zero);
-
-  // Allocate heap number for result if possible.
-  Result scratch = allocator()->Allocate();
-  Result heap_number = allocator()->Allocate();
-  __ AllocateHeapNumber(heap_number.reg(),
-                        scratch.reg(),
-                        call_runtime.entry_label());
-  scratch.Unuse();
-
-  // Store the result in the allocated heap number.
-  __ fstp_d(FieldOperand(heap_number.reg(), HeapNumber::kValueOffset));
-  // Replace the extra copy of the argument with the result.
-  frame_->SetElementAt(0, &heap_number);
-  done.Jump();
-
-  call_runtime.Bind();
-  // Free ST(0) which was not popped before calling into the runtime.
-  __ ffree(0);
-  Result answer;
-  switch (op) {
-    case SIN:
-      answer = frame_->CallRuntime(Runtime::kMath_sin, 1);
-      break;
-    case COS:
-      answer = frame_->CallRuntime(Runtime::kMath_cos, 1);
-      break;
-  }
-  frame_->Push(&answer);
-  done.Bind();
+  Load(args->at(1));
+  Load(args->at(2));
+  Load(args->at(3));
+  Result result = frame_->CallRuntime(Runtime::kRegExpExec, 4);
+  frame_->Push(&result);
 }
 
 
@@ -4057,6 +3919,29 @@
 }
 
 
+void CodeGenerator::GenerateSubString(ZoneList<Expression*>* args) {
+  ASSERT_EQ(3, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+  Load(args->at(2));
+
+  Result answer = frame_->CallRuntime(Runtime::kSubString, 3);
+  frame_->Push(&answer);
+}
+
+
+void CodeGenerator::GenerateStringCompare(ZoneList<Expression*>* args) {
+  ASSERT_EQ(2, args->length());
+
+  Load(args->at(0));
+  Load(args->at(1));
+
+  Result answer = frame_->CallRuntime(Runtime::kStringCompare, 2);
+  frame_->Push(&answer);
+}
+
+
 void CodeGenerator::GenerateClassOf(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   JumpTarget leave, null, function, non_function_constructor;
@@ -4380,15 +4265,7 @@
     // The expression is either a property or a variable proxy that rewrites
     // to a property.
     Load(property->obj());
-    // We use a named reference if the key is a literal symbol, unless it is
-    // a string that can be legally parsed as an integer.  This is because
-    // otherwise we will not get into the slow case code that handles [] on
-    // String objects.
-    Literal* literal = property->key()->AsLiteral();
-    uint32_t dummy;
-    if (literal != NULL &&
-        literal->handle()->IsSymbol() &&
-        !String::cast(*(literal->handle()))->AsArrayIndex(&dummy)) {
+    if (property->key()->IsPropertyName()) {
       ref->set_type(Reference::NAMED);
     } else {
       Load(property->key());
@@ -4864,36 +4741,34 @@
     frame_->Push(&result);
   }
 
-  { Reference shadow_ref(this, scope_->arguments_shadow());
-    Reference arguments_ref(this, scope_->arguments());
-    ASSERT(shadow_ref.is_slot() && arguments_ref.is_slot());
-    // Here we rely on the convenient property that references to slot
-    // take up zero space in the frame (ie, it doesn't matter that the
-    // stored value is actually below the reference on the frame).
-    JumpTarget done;
-    bool skip_arguments = false;
-    if (mode == LAZY_ARGUMENTS_ALLOCATION && !initial) {
-      // We have to skip storing into the arguments slot if it has
-      // already been written to. This can happen if the a function
-      // has a local variable named 'arguments'.
-      LoadFromSlot(scope_->arguments()->var()->slot(), NOT_INSIDE_TYPEOF);
-      Result arguments = frame_->Pop();
-      if (arguments.is_constant()) {
-        // We have to skip updating the arguments object if it has
-        // been assigned a proper value.
-        skip_arguments = !arguments.handle()->IsTheHole();
-      } else {
-        __ CompareRoot(arguments.reg(), Heap::kTheHoleValueRootIndex);
-        arguments.Unuse();
-        done.Branch(not_equal);
-      }
+
+  Variable* arguments = scope_->arguments()->var();
+  Variable* shadow = scope_->arguments_shadow()->var();
+  ASSERT(arguments != NULL && arguments->slot() != NULL);
+  ASSERT(shadow != NULL && shadow->slot() != NULL);
+  JumpTarget done;
+  bool skip_arguments = false;
+  if (mode == LAZY_ARGUMENTS_ALLOCATION && !initial) {
+    // We have to skip storing into the arguments slot if it has
+    // already been written to. This can happen if the a function
+    // has a local variable named 'arguments'.
+    LoadFromSlot(scope_->arguments()->var()->slot(), NOT_INSIDE_TYPEOF);
+    Result probe = frame_->Pop();
+    if (probe.is_constant()) {
+      // We have to skip updating the arguments object if it has been
+      // assigned a proper value.
+      skip_arguments = !probe.handle()->IsTheHole();
+    } else {
+      __ CompareRoot(probe.reg(), Heap::kTheHoleValueRootIndex);
+      probe.Unuse();
+      done.Branch(not_equal);
     }
-    if (!skip_arguments) {
-      arguments_ref.SetValue(NOT_CONST_INIT);
-      if (mode == LAZY_ARGUMENTS_ALLOCATION) done.Bind();
-    }
-    shadow_ref.SetValue(NOT_CONST_INIT);
   }
+  if (!skip_arguments) {
+    StoreToSlot(arguments->slot(), NOT_CONST_INIT);
+    if (mode == LAZY_ARGUMENTS_ALLOCATION) done.Bind();
+  }
+  StoreToSlot(shadow->slot(), NOT_CONST_INIT);
   return frame_->Pop();
 }
 
@@ -6199,6 +6074,91 @@
 }
 
 
+void FastNewClosureStub::Generate(MacroAssembler* masm) {
+  // Clone the boilerplate in new space. Set the context to the
+  // current context in rsi.
+  Label gc;
+  __ AllocateInNewSpace(JSFunction::kSize, rax, rbx, rcx, &gc, TAG_OBJECT);
+
+  // Get the boilerplate function from the stack.
+  __ movq(rdx, Operand(rsp, 1 * kPointerSize));
+
+  // Compute the function map in the current global context and set that
+  // as the map of the allocated object.
+  __ movq(rcx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(rcx, FieldOperand(rcx, GlobalObject::kGlobalContextOffset));
+  __ movq(rcx, Operand(rcx, Context::SlotOffset(Context::FUNCTION_MAP_INDEX)));
+  __ movq(FieldOperand(rax, JSObject::kMapOffset), rcx);
+
+  // Clone the rest of the boilerplate fields. We don't have to update
+  // the write barrier because the allocated object is in new space.
+  for (int offset = kPointerSize;
+       offset < JSFunction::kSize;
+       offset += kPointerSize) {
+    if (offset == JSFunction::kContextOffset) {
+      __ movq(FieldOperand(rax, offset), rsi);
+    } else {
+      __ movq(rbx, FieldOperand(rdx, offset));
+      __ movq(FieldOperand(rax, offset), rbx);
+    }
+  }
+
+  // Return and remove the on-stack parameter.
+  __ ret(1 * kPointerSize);
+
+  // Create a new closure through the slower runtime call.
+  __ bind(&gc);
+  __ pop(rcx);  // Temporarily remove return address.
+  __ pop(rdx);
+  __ push(rsi);
+  __ push(rdx);
+  __ push(rcx);  // Restore return address.
+  __ TailCallRuntime(ExternalReference(Runtime::kNewClosure), 2, 1);
+}
+
+
+void FastNewContextStub::Generate(MacroAssembler* masm) {
+  // Try to allocate the context in new space.
+  Label gc;
+  int length = slots_ + Context::MIN_CONTEXT_SLOTS;
+  __ AllocateInNewSpace((length * kPointerSize) + FixedArray::kHeaderSize,
+                        rax, rbx, rcx, &gc, TAG_OBJECT);
+
+  // Get the function from the stack.
+  __ movq(rcx, Operand(rsp, 1 * kPointerSize));
+
+  // Setup the object header.
+  __ LoadRoot(kScratchRegister, Heap::kContextMapRootIndex);
+  __ movq(FieldOperand(rax, HeapObject::kMapOffset), kScratchRegister);
+  __ movl(FieldOperand(rax, Array::kLengthOffset), Immediate(length));
+
+  // Setup the fixed slots.
+  __ xor_(rbx, rbx);  // Set to NULL.
+  __ movq(Operand(rax, Context::SlotOffset(Context::CLOSURE_INDEX)), rcx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::FCONTEXT_INDEX)), rax);
+  __ movq(Operand(rax, Context::SlotOffset(Context::PREVIOUS_INDEX)), rbx);
+  __ movq(Operand(rax, Context::SlotOffset(Context::EXTENSION_INDEX)), rbx);
+
+  // Copy the global object from the surrounding context.
+  __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  __ movq(Operand(rax, Context::SlotOffset(Context::GLOBAL_INDEX)), rbx);
+
+  // Initialize the rest of the slots to undefined.
+  __ LoadRoot(rbx, Heap::kUndefinedValueRootIndex);
+  for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+    __ movq(Operand(rax, Context::SlotOffset(i)), rbx);
+  }
+
+  // Return and remove the on-stack parameter.
+  __ movq(rsi, rax);
+  __ ret(1 * kPointerSize);
+
+  // Need to collect. Call into runtime system.
+  __ bind(&gc);
+  __ TailCallRuntime(ExternalReference(Runtime::kNewContext), 1, 1);
+}
+
+
 void ToBooleanStub::Generate(MacroAssembler* masm) {
   Label false_result, true_result, not_string;
   __ movq(rax, Operand(rsp, 1 * kPointerSize));
@@ -6338,7 +6298,9 @@
 
 // End of CodeGenerator implementation.
 
-void UnarySubStub::Generate(MacroAssembler* masm) {
+void GenericUnaryOpStub::Generate(MacroAssembler* masm) {
+  ASSERT(op_ == Token::SUB);
+
   Label slow;
   Label done;
   Label try_float;
@@ -6406,34 +6368,39 @@
       // Test for NaN. Sadly, we can't just compare to Factory::nan_value(),
       // so we do the second best thing - test it ourselves.
 
-      Label return_equal;
-      Label heap_number;
-      // If it's not a heap number, then return equal.
-      __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
-             Factory::heap_number_map());
-      __ j(equal, &heap_number);
-      __ bind(&return_equal);
-      __ xor_(rax, rax);
-      __ ret(0);
+      if (never_nan_nan_) {
+        __ xor_(rax, rax);
+        __ ret(0);
+      } else {
+        Label return_equal;
+        Label heap_number;
+        // If it's not a heap number, then return equal.
+        __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
+               Factory::heap_number_map());
+        __ j(equal, &heap_number);
+        __ bind(&return_equal);
+        __ xor_(rax, rax);
+        __ ret(0);
 
-      __ bind(&heap_number);
-      // It is a heap number, so return non-equal if it's NaN and equal if it's
-      // not NaN.
-      // The representation of NaN values has all exponent bits (52..62) set,
-      // and not all mantissa bits (0..51) clear.
-      // We only allow QNaNs, which have bit 51 set (which also rules out
-      // the value being Infinity).
+        __ bind(&heap_number);
+        // It is a heap number, so return non-equal if it's NaN and equal if
+        // it's not NaN.
+        // The representation of NaN values has all exponent bits (52..62) set,
+        // and not all mantissa bits (0..51) clear.
+        // We only allow QNaNs, which have bit 51 set (which also rules out
+        // the value being Infinity).
 
-      // Value is a QNaN if value & kQuietNaNMask == kQuietNaNMask, i.e.,
-      // all bits in the mask are set. We only need to check the word
-      // that contains the exponent and high bit of the mantissa.
-      ASSERT_NE(0, (kQuietNaNHighBitsMask << 1) & 0x80000000u);
-      __ movl(rdx, FieldOperand(rdx, HeapNumber::kExponentOffset));
-      __ xorl(rax, rax);
-      __ addl(rdx, rdx);  // Shift value and mask so mask applies to top bits.
-      __ cmpl(rdx, Immediate(kQuietNaNHighBitsMask << 1));
-      __ setcc(above_equal, rax);
-      __ ret(0);
+        // Value is a QNaN if value & kQuietNaNMask == kQuietNaNMask, i.e.,
+        // all bits in the mask are set. We only need to check the word
+        // that contains the exponent and high bit of the mantissa.
+        ASSERT_NE(0, (kQuietNaNHighBitsMask << 1) & 0x80000000u);
+        __ movl(rdx, FieldOperand(rdx, HeapNumber::kExponentOffset));
+        __ xorl(rax, rax);
+        __ addl(rdx, rdx);  // Shift value and mask so mask applies to top bits.
+        __ cmpl(rdx, Immediate(kQuietNaNHighBitsMask << 1));
+        __ setcc(above_equal, rax);
+        __ ret(0);
+      }
 
       __ bind(&not_identical);
     }
@@ -6580,9 +6547,11 @@
   __ movq(scratch, FieldOperand(object, HeapObject::kMapOffset));
   __ movzxbq(scratch,
              FieldOperand(scratch, Map::kInstanceTypeOffset));
-  __ and_(scratch, Immediate(kIsSymbolMask | kIsNotStringMask));
-  __ cmpb(scratch, Immediate(kSymbolTag | kStringTag));
-  __ j(not_equal, label);
+  // Ensure that no non-strings have the symbol bit set.
+  ASSERT(kNotStringTag + kIsSymbolMask > LAST_TYPE);
+  ASSERT(kSymbolTag != 0);
+  __ testb(scratch, Immediate(kIsSymbolMask));
+  __ j(zero, label);
 }
 
 
@@ -6761,16 +6730,13 @@
   __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
   __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
                 Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-  __ j(equal, &adaptor);
-
-  // Nothing to do: The formal number of parameters has already been
-  // passed in register rax by calling function. Just return it.
-  __ ret(0);
 
   // Arguments adaptor case: Read the arguments length from the
   // adaptor frame and return it.
-  __ bind(&adaptor);
-  __ movq(rax, Operand(rdx, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  // Otherwise nothing to do: The number of formal parameters has already been
+  // passed in register eax by calling function. Just return it.
+  __ cmovq(equal, rax,
+           Operand(rdx, ArgumentsAdaptorFrameConstants::kLengthOffset));
   __ ret(0);
 }
 
@@ -7885,9 +7851,52 @@
 
 
 int CompareStub::MinorKey() {
-  // Encode the two parameters in a unique 16 bit value.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
-  return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
+  // Encode the three parameters in a unique 16 bit value.
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 14));
+  int nnn_value = (never_nan_nan_ ? 2 : 0);
+  if (cc_ != equal) nnn_value = 0;  // Avoid duplicate stubs.
+  return (static_cast<unsigned>(cc_) << 2) | nnn_value | (strict_ ? 1 : 0);
+}
+
+
+const char* CompareStub::GetName() {
+  switch (cc_) {
+    case less: return "CompareStub_LT";
+    case greater: return "CompareStub_GT";
+    case less_equal: return "CompareStub_LE";
+    case greater_equal: return "CompareStub_GE";
+    case not_equal: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_NE_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_NE_NO_NAN";
+        } else {
+          return "CompareStub_NE";
+        }
+      }
+    }
+    case equal: {
+      if (strict_) {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_STRICT_NO_NAN";
+        } else {
+          return "CompareStub_EQ_STRICT";
+        }
+      } else {
+        if (never_nan_nan_) {
+          return "CompareStub_EQ_NO_NAN";
+        } else {
+          return "CompareStub_EQ";
+        }
+      }
+    }
+    default: return "CompareStub";
+  }
 }
 
 
diff --git a/src/x64/codegen-x64.h b/src/x64/codegen-x64.h
index fdace8d..fa90f02 100644
--- a/src/x64/codegen-x64.h
+++ b/src/x64/codegen-x64.h
@@ -538,15 +538,18 @@
   // Fast support for Math.random().
   void GenerateRandomPositiveSmi(ZoneList<Expression*>* args);
 
-  // Fast support for Math.sin and Math.cos.
-  enum MathOp { SIN, COS };
-  void GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args);
-  inline void GenerateMathSin(ZoneList<Expression*>* args);
-  inline void GenerateMathCos(ZoneList<Expression*>* args);
-
   // Fast support for StringAdd.
   void GenerateStringAdd(ZoneList<Expression*>* args);
 
+  // Fast support for SubString.
+  void GenerateSubString(ZoneList<Expression*>* args);
+
+  // Fast support for StringCompare.
+  void GenerateStringCompare(ZoneList<Expression*>* args);
+
+  // Support for direct calls from JavaScript to native RegExp code.
+  void GenerateRegExpExec(ZoneList<Expression*>* args);
+
   // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,
diff --git a/src/x64/fast-codegen-x64.cc b/src/x64/fast-codegen-x64.cc
index 7a991cb..3ef8678 100644
--- a/src/x64/fast-codegen-x64.cc
+++ b/src/x64/fast-codegen-x64.cc
@@ -202,33 +202,118 @@
 }
 
 
-void FastCodeGenerator::Move(Expression::Context context, Register source) {
+void FastCodeGenerator::Apply(Expression::Context context,
+                              Slot* slot,
+                              Register scratch) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      break;
+    case Expression::kValue: {
+      MemOperand location = EmitSlotSearch(slot, scratch);
+      __ push(location);
+      break;
+    }
+    case Expression::kTest:
+    case Expression::kValueTest:
+    case Expression::kTestValue:
+      Move(scratch, slot);
+      Apply(context, scratch);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::Apply(Expression::Context context, Literal* lit) {
   switch (context) {
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
       break;
     case Expression::kValue:
-      __ push(source);
+      __ Push(lit->handle());
       break;
     case Expression::kTest:
-      TestAndBranch(source, true_label_, false_label_);
+    case Expression::kValueTest:
+    case Expression::kTestValue:
+      __ Move(rax, lit->handle());
+      Apply(context, rax);
+      break;
+  }
+}
+
+
+void FastCodeGenerator::ApplyTOS(Expression::Context context) {
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(1);
+      break;
+    case Expression::kValue:
+      break;
+    case Expression::kTest:
+      __ pop(rax);
+      TestAndBranch(rax, true_label_, false_label_);
       break;
     case Expression::kValueTest: {
       Label discard;
-      __ push(source);
-      TestAndBranch(source, true_label_, &discard);
+      __ movq(rax, Operand(rsp, 0));
+      TestAndBranch(rax, true_label_, &discard);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
     case Expression::kTestValue: {
       Label discard;
-      __ push(source);
-      TestAndBranch(source, &discard, false_label_);
+      __ movq(rax, Operand(rsp, 0));
+      TestAndBranch(rax, &discard, false_label_);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
+      __ jmp(true_label_);
+    }
+  }
+}
+
+
+void FastCodeGenerator::DropAndApply(int count,
+                                     Expression::Context context,
+                                     Register reg) {
+  ASSERT(count > 0);
+  ASSERT(!reg.is(rsp));
+  switch (context) {
+    case Expression::kUninitialized:
+      UNREACHABLE();
+    case Expression::kEffect:
+      __ Drop(count);
+      break;
+    case Expression::kValue:
+      if (count > 1) __ Drop(count - 1);
+      __ movq(Operand(rsp, 0), reg);
+      break;
+    case Expression::kTest:
+      __ Drop(count);
+      TestAndBranch(reg, true_label_, false_label_);
+      break;
+    case Expression::kValueTest: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ movq(Operand(rsp, 0), reg);
+      TestAndBranch(reg, true_label_, &discard);
+      __ bind(&discard);
+      __ Drop(1);
+      __ jmp(false_label_);
+      break;
+    }
+    case Expression::kTestValue: {
+      Label discard;
+      if (count > 1) __ Drop(count - 1);
+      __ movq(Operand(rsp, 0), reg);
+      TestAndBranch(reg, &discard, false_label_);
+      __ bind(&discard);
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -236,75 +321,28 @@
 }
 
 
-template <>
-Operand FastCodeGenerator::CreateSlotOperand<Operand>(Slot* source,
-                                                      Register scratch) {
-  switch (source->type()) {
+MemOperand FastCodeGenerator::EmitSlotSearch(Slot* slot, Register scratch) {
+  switch (slot->type()) {
     case Slot::PARAMETER:
     case Slot::LOCAL:
-      return Operand(rbp, SlotOffset(source));
+      return Operand(rbp, SlotOffset(slot));
     case Slot::CONTEXT: {
       int context_chain_length =
-          function_->scope()->ContextChainLength(source->var()->scope());
+          function_->scope()->ContextChainLength(slot->var()->scope());
       __ LoadContext(scratch, context_chain_length);
-      return CodeGenerator::ContextOperand(scratch, source->index());
-      break;
+      return CodeGenerator::ContextOperand(scratch, slot->index());
     }
     case Slot::LOOKUP:
-      UNIMPLEMENTED();
-      // Fall-through.
-    default:
       UNREACHABLE();
-      return Operand(rax, 0);  // Dead code to make the compiler happy.
   }
+  UNREACHABLE();
+  return Operand(rax, 0);
 }
 
 
-void FastCodeGenerator::Move(Register dst, Slot* source) {
-  Operand location = CreateSlotOperand<Operand>(source, dst);
-  __ movq(dst, location);
-}
-
-
-void FastCodeGenerator::Move(Expression::Context context,
-                             Slot* source,
-                             Register scratch) {
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      break;
-    case Expression::kValue: {
-      Operand location = CreateSlotOperand<Operand>(source, scratch);
-      __ push(location);
-      break;
-    }
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
-    case Expression::kTestValue:
-      Move(scratch, source);
-      Move(context, scratch);
-      break;
-  }
-}
-
-
-void FastCodeGenerator::Move(Expression::Context context, Literal* expr) {
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      break;
-    case Expression::kValue:
-      __ Push(expr->handle());
-      break;
-    case Expression::kTest:  // Fall through.
-    case Expression::kValueTest:  // Fall through.
-    case Expression::kTestValue:
-      __ Move(rax, expr->handle());
-      Move(context, rax);
-      break;
-  }
+void FastCodeGenerator::Move(Register destination, Slot* source) {
+  MemOperand location = EmitSlotSearch(source, destination);
+  __ movq(destination, location);
 }
 
 
@@ -312,73 +350,14 @@
                              Register src,
                              Register scratch1,
                              Register scratch2) {
-  switch (dst->type()) {
-    case Slot::PARAMETER:
-    case Slot::LOCAL:
-      __ movq(Operand(rbp, SlotOffset(dst)), src);
-      break;
-    case Slot::CONTEXT: {
-      ASSERT(!src.is(scratch1));
-      ASSERT(!src.is(scratch2));
-      ASSERT(!scratch1.is(scratch2));
-      int context_chain_length =
-          function_->scope()->ContextChainLength(dst->var()->scope());
-      __ LoadContext(scratch1, context_chain_length);
-      __ movq(Operand(scratch1, Context::SlotOffset(dst->index())), src);
-      int offset = FixedArray::kHeaderSize + dst->index() * kPointerSize;
-      __ RecordWrite(scratch1, offset, src, scratch2);
-      break;
-    }
-    case Slot::LOOKUP:
-      UNIMPLEMENTED();
-    default:
-      UNREACHABLE();
-  }
-}
-
-
-void FastCodeGenerator::DropAndMove(Expression::Context context,
-                                    Register source,
-                                    int drop_count) {
-  ASSERT(drop_count > 0);
-  switch (context) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:
-      __ addq(rsp, Immediate(drop_count * kPointerSize));
-      break;
-    case Expression::kValue:
-      if (drop_count > 1) {
-        __ addq(rsp, Immediate((drop_count - 1) * kPointerSize));
-      }
-      __ movq(Operand(rsp, 0), source);
-      break;
-    case Expression::kTest:
-      ASSERT(!source.is(rsp));
-      __ addq(rsp, Immediate(drop_count * kPointerSize));
-      TestAndBranch(source, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      if (drop_count > 1) {
-        __ addq(rsp, Immediate((drop_count - 1) * kPointerSize));
-      }
-      __ movq(Operand(rsp, 0), source);
-      TestAndBranch(source, true_label_, &discard);
-      __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
-      __ jmp(false_label_);
-      break;
-    }
-    case Expression::kTestValue: {
-      Label discard;
-      __ movq(Operand(rsp, 0), source);
-      TestAndBranch(source, &discard, false_label_);
-      __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
-      __ jmp(true_label_);
-      break;
-    }
+  ASSERT(dst->type() != Slot::LOOKUP);  // Not yet implemented.
+  ASSERT(!scratch1.is(src) && !scratch2.is(src));
+  MemOperand location = EmitSlotSearch(dst, scratch1);
+  __ movq(location, src);
+  // Emit the write barrier code if the location is in the heap.
+  if (dst->type() == Slot::CONTEXT) {
+    int offset = FixedArray::kHeaderSize + dst->index() * kPointerSize;
+    __ RecordWrite(scratch1, offset, src, scratch2);
   }
 }
 
@@ -424,18 +403,21 @@
 
   if (slot != NULL) {
     switch (slot->type()) {
-      case Slot::PARAMETER:  // Fall through.
+      case Slot::PARAMETER:
       case Slot::LOCAL:
         if (decl->mode() == Variable::CONST) {
           __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
-          __ movq(Operand(rbp, SlotOffset(var->slot())), kScratchRegister);
+          __ movq(Operand(rbp, SlotOffset(slot)), kScratchRegister);
         } else if (decl->fun() != NULL) {
           Visit(decl->fun());
-          __ pop(Operand(rbp, SlotOffset(var->slot())));
+          __ pop(Operand(rbp, SlotOffset(slot)));
         }
         break;
 
       case Slot::CONTEXT:
+        // We bypass the general EmitSlotSearch because we know more about
+        // this specific context.
+
         // The variable in the decl always resides in the current context.
         ASSERT_EQ(0, function_->scope()->ContextChainLength(var->scope()));
         if (FLAG_debug_code) {
@@ -509,7 +491,7 @@
 
       // Value in rax is ignored (declarations are statements).  Receiver
       // and key on stack are discarded.
-      __ addq(rsp, Immediate(2 * kPointerSize));
+      __ Drop(2);
     }
   }
 }
@@ -539,7 +521,7 @@
   __ push(rsi);
   __ Push(boilerplate);
   __ CallRuntime(Runtime::kNewClosure, 2);
-  Move(expr->context(), rax);
+  Apply(expr->context(), rax);
 }
 
 
@@ -566,7 +548,7 @@
     // is no test rax instruction here.
     __ nop();
 
-    DropAndMove(context, rax);
+    DropAndApply(1, context, rax);
   } else if (rewrite->AsSlot() != NULL) {
     Slot* slot = rewrite->AsSlot();
     if (FLAG_debug_code) {
@@ -583,45 +565,45 @@
         case Slot::LOOKUP:
           UNIMPLEMENTED();
           break;
-        default:
-          UNREACHABLE();
       }
     }
-    Move(context, slot, rax);
+    Apply(context, slot, rax);
   } else {
-    // A variable has been rewritten into an explicit access to
-    // an object property.
+    Comment cmnt(masm_, "Variable rewritten to property");
+    // A variable has been rewritten into an explicit access to an object
+    // property.
     Property* property = rewrite->AsProperty();
     ASSERT_NOT_NULL(property);
 
-    // Currently the only parameter expressions that can occur are
-    // on the form "slot[literal]".
+    // The only property expressions that can occur are of the form
+    // "slot[literal]".
 
-    // Check that the object is in a slot.
+    // Assert that the object is in a slot.
     Variable* object = property->obj()->AsVariableProxy()->AsVariable();
     ASSERT_NOT_NULL(object);
     Slot* object_slot = object->slot();
     ASSERT_NOT_NULL(object_slot);
 
     // Load the object.
-    Move(Expression::kValue, object_slot, rax);
+    MemOperand object_loc = EmitSlotSearch(object_slot, rax);
+    __ push(object_loc);
 
-    // Check that the key is a smi.
+    // Assert that the key is a smi.
     Literal* key_literal = property->key()->AsLiteral();
     ASSERT_NOT_NULL(key_literal);
     ASSERT(key_literal->handle()->IsSmi());
 
     // Load the key.
-    Move(Expression::kValue, key_literal);
+    __ Push(key_literal->handle());
 
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
-    // Notice: We must not have a "test rax, ..." instruction after
-    // the call. It is treated specially by the LoadIC code.
+    // Notice: We must not have a "test rax, ..." instruction after the
+    // call. It is treated specially by the LoadIC code.
 
     // Drop key and object left on the stack by IC, and push the result.
-    DropAndMove(context, rax, 2);
+    DropAndApply(2, context, rax);
   }
 }
 
@@ -649,7 +631,7 @@
   __ CallRuntime(Runtime::kMaterializeRegExpLiteral, 4);
   // Label done:
   __ bind(&done);
-  Move(expr->context(), rax);
+  Apply(expr->context(), rax);
 }
 
 
@@ -681,7 +663,7 @@
       result_saved = true;
     }
     switch (property->kind()) {
-      case ObjectLiteral::Property::MATERIALIZED_LITERAL:  // fall through
+      case ObjectLiteral::Property::MATERIALIZED_LITERAL:
         ASSERT(!CompileTimeValue::IsCompileTimeValue(value));
       case ObjectLiteral::Property::COMPUTED:
         if (key->handle()->IsSymbol()) {
@@ -695,7 +677,7 @@
           __ movq(rax, Operand(rsp, 0));  // Restore result back into rax.
           break;
         }
-        // fall through
+        // Fall through.
       case ObjectLiteral::Property::PROTOTYPE:
         __ push(rax);
         Visit(key);
@@ -705,7 +687,7 @@
         __ CallRuntime(Runtime::kSetProperty, 3);
         __ movq(rax, Operand(rsp, 0));  // Restore result into rax.
         break;
-      case ObjectLiteral::Property::SETTER:  // fall through
+      case ObjectLiteral::Property::SETTER:
       case ObjectLiteral::Property::GETTER:
         __ push(rax);
         Visit(key);
@@ -725,7 +707,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ addq(rsp, Immediate(kPointerSize));
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(rax);
@@ -739,7 +721,7 @@
       if (!result_saved) __ push(rax);
       TestAndBranch(rax, true_label_, &discard);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -748,7 +730,7 @@
       if (!result_saved) __ push(rax);
       TestAndBranch(rax, &discard, false_label_);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -761,7 +743,7 @@
   __ movq(rbx, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
   __ push(FieldOperand(rbx, JSFunction::kLiteralsOffset));
   __ Push(Smi::FromInt(expr->literal_index()));
-  __ Push(expr->literals());
+  __ Push(expr->constant_elements());
   if (expr->depth() > 1) {
     __ CallRuntime(Runtime::kCreateArrayLiteral, 3);
   } else {
@@ -804,7 +786,7 @@
     case Expression::kUninitialized:
       UNREACHABLE();
     case Expression::kEffect:
-      if (result_saved) __ addq(rsp, Immediate(kPointerSize));
+      if (result_saved) __ Drop(1);
       break;
     case Expression::kValue:
       if (!result_saved) __ push(rax);
@@ -818,7 +800,7 @@
       if (!result_saved) __ push(rax);
       TestAndBranch(rax, true_label_, &discard);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(false_label_);
       break;
     }
@@ -827,7 +809,7 @@
       if (!result_saved) __ push(rax);
       TestAndBranch(rax, &discard, false_label_);
       __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       __ jmp(true_label_);
       break;
     }
@@ -837,18 +819,21 @@
 
 void FastCodeGenerator::EmitNamedPropertyLoad(Property* prop,
                                               Expression::Context context) {
+  SetSourcePosition(prop->position());
   Literal* key = prop->key()->AsLiteral();
   __ Move(rcx, key->handle());
   Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
   __ Call(ic, RelocInfo::CODE_TARGET);
-  Move(context, rax);
+  Apply(context, rax);
 }
 
 
-void FastCodeGenerator::EmitKeyedPropertyLoad(Expression::Context context) {
+void FastCodeGenerator::EmitKeyedPropertyLoad(Property* prop,
+                                              Expression::Context context) {
+  SetSourcePosition(prop->position());
   Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
   __ Call(ic, RelocInfo::CODE_TARGET);
-  Move(context, rax);
+  Apply(context, rax);
 }
 
 
@@ -858,12 +843,12 @@
                            NO_OVERWRITE,
                            NO_GENERIC_BINARY_FLAGS);
   __ CallStub(&stub);
-  Move(context, rax);
+  Apply(context, rax);
 }
 
 
-void FastCodeGenerator::EmitVariableAssignment(Assignment* expr) {
-  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
+void FastCodeGenerator::EmitVariableAssignment(Variable* var,
+                                               Expression::Context context) {
   ASSERT(var != NULL);
   ASSERT(var->is_global() || var->slot() != NULL);
   if (var->is_global()) {
@@ -876,49 +861,49 @@
     Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
     __ Call(ic, RelocInfo::CODE_TARGET);
     // Overwrite the global object on the stack with the result if needed.
-    DropAndMove(expr->context(), rax);
+    DropAndApply(1, context, rax);
 
-  } else if (var->slot()) {
+  } else if (var->slot() != NULL) {
     Slot* slot = var->slot();
-    ASSERT_NOT_NULL(slot);  // Variables rewritten as properties not handled.
     switch (slot->type()) {
       case Slot::LOCAL:
       case Slot::PARAMETER: {
-        switch (expr->context()) {
+        Operand target = Operand(rbp, SlotOffset(slot));
+        switch (context) {
           case Expression::kUninitialized:
             UNREACHABLE();
           case Expression::kEffect:
             // Perform assignment and discard value.
-            __ pop(Operand(rbp, SlotOffset(var->slot())));
+            __ pop(target);
             break;
           case Expression::kValue:
             // Perform assignment and preserve value.
             __ movq(rax, Operand(rsp, 0));
-            __ movq(Operand(rbp, SlotOffset(var->slot())), rax);
+            __ movq(target, rax);
             break;
           case Expression::kTest:
             // Perform assignment and test (and discard) value.
             __ pop(rax);
-            __ movq(Operand(rbp, SlotOffset(var->slot())), rax);
+            __ movq(target, rax);
             TestAndBranch(rax, true_label_, false_label_);
             break;
           case Expression::kValueTest: {
             Label discard;
             __ movq(rax, Operand(rsp, 0));
-            __ movq(Operand(rbp, SlotOffset(var->slot())), rax);
+            __ movq(target, rax);
             TestAndBranch(rax, true_label_, &discard);
             __ bind(&discard);
-            __ addq(rsp, Immediate(kPointerSize));
+            __ Drop(1);
             __ jmp(false_label_);
             break;
           }
           case Expression::kTestValue: {
             Label discard;
             __ movq(rax, Operand(rsp, 0));
-            __ movq(Operand(rbp, SlotOffset(var->slot())), rax);
+            __ movq(target, rax);
             TestAndBranch(rax, &discard, false_label_);
             __ bind(&discard);
-            __ addq(rsp, Immediate(kPointerSize));
+            __ Drop(1);
             __ jmp(true_label_);
             break;
           }
@@ -927,41 +912,20 @@
       }
 
       case Slot::CONTEXT: {
-        int chain_length =
-            function_->scope()->ContextChainLength(slot->var()->scope());
-        if (chain_length > 0) {
-          // Move up the context chain to the context containing the slot.
-          __ movq(rax,
-                  Operand(rsi, Context::SlotOffset(Context::CLOSURE_INDEX)));
-          // Load the function context (which is the incoming, outer context).
-          __ movq(rax, FieldOperand(rax, JSFunction::kContextOffset));
-          for (int i = 1; i < chain_length; i++) {
-            __ movq(rax,
-                    Operand(rax, Context::SlotOffset(Context::CLOSURE_INDEX)));
-            __ movq(rax, FieldOperand(rax, JSFunction::kContextOffset));
-          }
-        } else {  // Slot is in the current context.  Generate optimized code.
-          __ movq(rax, rsi);  // RecordWrite destroys the object register.
-        }
-        if (FLAG_debug_code) {
-          __ cmpq(rax,
-                  Operand(rax, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-          __ Check(equal, "Context Slot chain length wrong.");
-        }
-        __ pop(rcx);
-        __ movq(Operand(rax, Context::SlotOffset(slot->index())), rcx);
+        MemOperand target = EmitSlotSearch(slot, rcx);
+        __ pop(rax);
+        __ movq(target, rax);
 
         // RecordWrite may destroy all its register arguments.
-        if (expr->context() == Expression::kValue) {
-          __ push(rcx);
-        } else if (expr->context() != Expression::kEffect) {
-          __ movq(rdx, rcx);
+        if (context == Expression::kValue) {
+          __ push(rax);
+        } else if (context != Expression::kEffect) {
+          __ movq(rdx, rax);
         }
         int offset = FixedArray::kHeaderSize + slot->index() * kPointerSize;
-        __ RecordWrite(rax, offset, rcx, rbx);
-        if (expr->context() != Expression::kEffect &&
-            expr->context() != Expression::kValue) {
-          Move(expr->context(), rdx);
+        __ RecordWrite(rcx, offset, rax, rbx);
+        if (context != Expression::kEffect && context != Expression::kValue) {
+          Apply(context, rdx);
         }
         break;
       }
@@ -970,6 +934,10 @@
         UNREACHABLE();
         break;
     }
+  } else {
+    // Variables rewritten as properties are not treated as variables in
+    // assignments.
+    UNREACHABLE();
   }
 }
 
@@ -1001,7 +969,7 @@
     __ pop(rax);
   }
 
-  DropAndMove(expr->context(), rax);
+  DropAndApply(1, expr->context(), rax);
 }
 
 
@@ -1034,15 +1002,13 @@
   }
 
   // Receiver and key are still on stack.
-  __ addq(rsp, Immediate(2 * kPointerSize));
-  Move(expr->context(), rax);
+  DropAndApply(2, expr->context(), rax);
 }
 
 
 void FastCodeGenerator::VisitProperty(Property* expr) {
   Comment cmnt(masm_, "[ Property");
   Expression* key = expr->key();
-  uint32_t dummy;
 
   // Record the source position for the property load.
   SetSourcePosition(expr->position());
@@ -1050,29 +1016,27 @@
   // Evaluate receiver.
   Visit(expr->obj());
 
-
-  if (key->AsLiteral() != NULL && key->AsLiteral()->handle()->IsSymbol() &&
-      !String::cast(*(key->AsLiteral()->handle()))->AsArrayIndex(&dummy)) {
-    // Do a NAMED property load.
-    // The IC expects the property name in rcx and the receiver on the stack.
+  if (key->IsPropertyName()) {
+    // Do a named property load.  The IC expects the property name in rcx
+    // and the receiver on the stack.
     __ Move(rcx, key->AsLiteral()->handle());
     Handle<Code> ic(Builtins::builtin(Builtins::LoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
     // By emitting a nop we make sure that we do not have a "test rax,..."
     // instruction after the call it is treated specially by the LoadIC code.
     __ nop();
+    DropAndApply(1, expr->context(), rax);
   } else {
-    // Do a KEYED property load.
+    // Do a keyed property load.
     Visit(expr->key());
     Handle<Code> ic(Builtins::builtin(Builtins::KeyedLoadIC_Initialize));
     __ call(ic, RelocInfo::CODE_TARGET);
-    // Notice: We must not have a "test rax, ..." instruction after
-    // the call. It is treated specially by the LoadIC code.
-
-    // Drop key left on the stack by IC.
-    __ addq(rsp, Immediate(kPointerSize));
+    // Notice: We must not have a "test rax, ..." instruction after the
+    // call. It is treated specially by the LoadIC code.
+    __ nop();
+    // Drop key and receiver left on the stack by IC.
+    DropAndApply(2, expr->context(), rax);
   }
-  DropAndMove(expr->context(), rax);
 }
 
 
@@ -1095,7 +1059,7 @@
   // Restore context register.
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
-  DropAndMove(expr->context(), rax);
+  DropAndApply(1, expr->context(), rax);
 }
 
 
@@ -1113,7 +1077,7 @@
   // Restore context register.
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   // Discard the function left on TOS.
-  DropAndMove(expr->context(), rax);
+  DropAndApply(1, expr->context(), rax);
 }
 
 
@@ -1157,14 +1121,15 @@
       // instruction after the call it is treated specially by the LoadIC code.
       __ nop();
       // Drop key left on the stack by IC.
-      __ addq(rsp, Immediate(kPointerSize));
+      __ Drop(1);
       // Pop receiver.
       __ pop(rbx);
       // Push result (function).
       __ push(rax);
       // Push receiver object on stack.
       if (prop->is_synthetic()) {
-        __ push(CodeGenerator::GlobalObject());
+        __ movq(rcx, CodeGenerator::GlobalObject());
+        __ push(FieldOperand(rcx, GlobalObject::kGlobalReceiverOffset));
       } else {
         __ push(rbx);
       }
@@ -1226,7 +1191,7 @@
   __ Call(construct_builtin, RelocInfo::CONSTRUCT_CALL);
 
   // Replace function on TOS with result in rax, or pop it.
-  DropAndMove(expr->context(), rax);
+  DropAndApply(1, expr->context(), rax);
 }
 
 
@@ -1256,82 +1221,10 @@
     // Restore context register.
     __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
     // Discard the function left on TOS.
-    DropAndMove(expr->context(), rax);
+    DropAndApply(1, expr->context(), rax);
   } else {
     __ CallRuntime(expr->function(), arg_count);
-    Move(expr->context(), rax);
-  }
-}
-
-void FastCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  Comment cmnt(masm_, "[ CountOperation");
-  VariableProxy* proxy = expr->expression()->AsVariableProxy();
-  ASSERT(proxy->AsVariable() != NULL);
-  ASSERT(proxy->AsVariable()->is_global());
-
-  Visit(proxy);
-  __ InvokeBuiltin(Builtins::TO_NUMBER, CALL_FUNCTION);
-
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kValue:  // Fall through
-    case Expression::kTest:  // Fall through
-    case Expression::kTestValue:  // Fall through
-    case Expression::kValueTest:
-      // Duplicate the result on the stack.
-      __ push(rax);
-      break;
-    case Expression::kEffect:
-      // Do not save result.
-      break;
-  }
-  // Call runtime for +1/-1.
-  __ push(rax);
-  __ Push(Smi::FromInt(1));
-  if (expr->op() == Token::INC) {
-    __ CallRuntime(Runtime::kNumberAdd, 2);
-  } else {
-    __ CallRuntime(Runtime::kNumberSub, 2);
-  }
-  // Call Store IC.
-  __ Move(rcx, proxy->AsVariable()->name());
-  __ push(CodeGenerator::GlobalObject());
-  Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
-  __ call(ic, RelocInfo::CODE_TARGET);
-  // Restore up stack after store IC
-  __ addq(rsp, Immediate(kPointerSize));
-
-  switch (expr->context()) {
-    case Expression::kUninitialized:
-      UNREACHABLE();
-    case Expression::kEffect:  // Fall through
-    case Expression::kValue:
-      // Do nothing. Result in either on the stack for value context
-      // or discarded for effect context.
-      break;
-    case Expression::kTest:
-      __ pop(rax);
-      TestAndBranch(rax, true_label_, false_label_);
-      break;
-    case Expression::kValueTest: {
-      Label discard;
-      __ movq(rax, Operand(rsp, 0));
-      TestAndBranch(rax, true_label_, &discard);
-      __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
-      __ jmp(false_label_);
-      break;
-    }
-    case Expression::kTestValue: {
-      Label discard;
-      __ movq(rax, Operand(rsp, 0));
-      TestAndBranch(rax, &discard, false_label_);
-      __ bind(&discard);
-      __ addq(rsp, Immediate(kPointerSize));
-      __ jmp(true_label_);
-      break;
-    }
+    Apply(expr->context(), rax);
   }
 }
 
@@ -1355,7 +1248,7 @@
           // Value is false so it's needed.
           __ PushRoot(Heap::kUndefinedValueRootIndex);
           // Fall through.
-        case Expression::kTest:  // Fall through.
+        case Expression::kTest:
         case Expression::kValueTest:
           __ jmp(false_label_);
           break;
@@ -1367,20 +1260,14 @@
       Comment cmnt(masm_, "[ UnaryOperation (NOT)");
       ASSERT_EQ(Expression::kTest, expr->expression()->context());
 
-      Label push_true;
-      Label push_false;
-      Label done;
-      Label* saved_true = true_label_;
-      Label* saved_false = false_label_;
+      Label push_true, push_false, done;
       switch (expr->context()) {
         case Expression::kUninitialized:
           UNREACHABLE();
           break;
 
         case Expression::kValue:
-          true_label_ = &push_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, &push_true);
           __ bind(&push_true);
           __ PushRoot(Heap::kTrueValueRootIndex);
           __ jmp(&done);
@@ -1390,38 +1277,28 @@
           break;
 
         case Expression::kEffect:
-          true_label_ = &done;
-          false_label_ = &done;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &done, &done);
           __ bind(&done);
           break;
 
         case Expression::kTest:
-          true_label_ = saved_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, true_label_);
           break;
 
         case Expression::kValueTest:
-          true_label_ = saved_false;
-          false_label_ = &push_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), false_label_, &push_true);
           __ bind(&push_true);
           __ PushRoot(Heap::kTrueValueRootIndex);
-          __ jmp(saved_true);
+          __ jmp(true_label_);
           break;
 
         case Expression::kTestValue:
-          true_label_ = &push_false;
-          false_label_ = saved_true;
-          Visit(expr->expression());
+          VisitForControl(expr->expression(), &push_false, true_label_);
           __ bind(&push_false);
           __ PushRoot(Heap::kFalseValueRootIndex);
-          __ jmp(saved_false);
+          __ jmp(false_label_);
           break;
       }
-      true_label_ = saved_true;
-      false_label_ = saved_false;
       break;
     }
 
@@ -1454,7 +1331,7 @@
       }
 
       __ CallRuntime(Runtime::kTypeof, 1);
-      Move(expr->context(), rax);
+      Apply(expr->context(), rax);
       break;
     }
 
@@ -1464,6 +1341,139 @@
 }
 
 
+void FastCodeGenerator::VisitCountOperation(CountOperation* expr) {
+  Comment cmnt(masm_, "[ CountOperation");
+
+  // Expression can only be a property, a global or a (parameter or local)
+  // slot. Variables with rewrite to .arguments are treated as KEYED_PROPERTY.
+  enum LhsKind { VARIABLE, NAMED_PROPERTY, KEYED_PROPERTY };
+  LhsKind assign_type = VARIABLE;
+  Property* prop = expr->expression()->AsProperty();
+  // In case of a property we use the uninitialized expression context
+  // of the key to detect a named property.
+  if (prop != NULL) {
+    assign_type = (prop->key()->context() == Expression::kUninitialized)
+        ? NAMED_PROPERTY
+        : KEYED_PROPERTY;
+  }
+
+  // Evaluate expression and get value.
+  if (assign_type == VARIABLE) {
+    ASSERT(expr->expression()->AsVariableProxy()->var() != NULL);
+    EmitVariableLoad(expr->expression()->AsVariableProxy()->var(),
+                     Expression::kValue);
+  } else  {
+    // Reserve space for result of postfix operation.
+    if (expr->is_postfix() && expr->context() != Expression::kEffect) {
+      ASSERT(expr->context() != Expression::kUninitialized);
+      __ Push(Smi::FromInt(0));
+    }
+    Visit(prop->obj());
+    ASSERT_EQ(Expression::kValue, prop->obj()->context());
+    if (assign_type == NAMED_PROPERTY) {
+      EmitNamedPropertyLoad(prop, Expression::kValue);
+    } else {
+      Visit(prop->key());
+      ASSERT_EQ(Expression::kValue, prop->key()->context());
+      EmitKeyedPropertyLoad(prop, Expression::kValue);
+    }
+  }
+
+  // Convert to number.
+  __ InvokeBuiltin(Builtins::TO_NUMBER, CALL_FUNCTION);
+
+  // Save result for postfix expressions.
+  if (expr->is_postfix()) {
+    switch (expr->context()) {
+      case Expression::kUninitialized:
+        UNREACHABLE();
+      case Expression::kEffect:
+        // Do not save result.
+        break;
+      case Expression::kValue:  // Fall through
+      case Expression::kTest:  // Fall through
+      case Expression::kTestValue:  // Fall through
+      case Expression::kValueTest:
+        // Save the result on the stack. If we have a named or keyed property
+        // we store the result under the receiver that is currently on top
+        // of the stack.
+        switch (assign_type) {
+          case VARIABLE:
+            __ push(rax);
+            break;
+          case NAMED_PROPERTY:
+            __ movq(Operand(rsp, kPointerSize), rax);
+            break;
+          case KEYED_PROPERTY:
+            __ movq(Operand(rsp, 2 * kPointerSize), rax);
+            break;
+        }
+        break;
+    }
+  }
+
+  // Call runtime for +1/-1.
+  __ push(rax);
+  __ Push(Smi::FromInt(1));
+  if (expr->op() == Token::INC) {
+    __ CallRuntime(Runtime::kNumberAdd, 2);
+  } else {
+    __ CallRuntime(Runtime::kNumberSub, 2);
+  }
+
+  // Store the value returned in rax.
+  switch (assign_type) {
+    case VARIABLE:
+      __ push(rax);
+      if (expr->is_postfix()) {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               Expression::kEffect);
+        // For all contexts except kEffect: We have the result on
+        // top of the stack.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
+                               expr->context());
+      }
+      break;
+    case NAMED_PROPERTY: {
+      __ Move(rcx, prop->key()->AsLiteral()->handle());
+      Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
+      __ call(ic, RelocInfo::CODE_TARGET);
+      // This nop signals to the IC that there is no inlined code at the call
+      // site for it to patch.
+      __ nop();
+      if (expr->is_postfix()) {
+        __ Drop(1);  // Result is on the stack under the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(1, expr->context(), rax);
+      }
+      break;
+    }
+    case KEYED_PROPERTY: {
+      Handle<Code> ic(Builtins::builtin(Builtins::KeyedStoreIC_Initialize));
+      __ call(ic, RelocInfo::CODE_TARGET);
+      // This nop signals to the IC that there is no inlined code at the call
+      // site for it to patch.
+      __ nop();
+      if (expr->is_postfix()) {
+        __ Drop(2);  // Result is on the stack under the key and the receiver.
+        if (expr->context() != Expression::kEffect) {
+          ApplyTOS(expr->context());
+        }
+      } else {
+        DropAndApply(2, expr->context(), rax);
+      }
+      break;
+    }
+  }
+}
+
 void FastCodeGenerator::VisitBinaryOperation(BinaryOperation* expr) {
   Comment cmnt(masm_, "[ BinaryOperation");
   switch (expr->op()) {
@@ -1499,7 +1509,7 @@
                                NO_OVERWRITE,
                                NO_GENERIC_BINARY_FLAGS);
       __ CallStub(&stub);
-      Move(expr->context(), rax);
+      Apply(expr->context(), rax);
 
       break;
     }
@@ -1516,46 +1526,40 @@
   Visit(expr->left());
   Visit(expr->right());
 
-  // Convert current context to test context: Pre-test code.
-  Label push_true;
-  Label push_false;
-  Label done;
-  Label* saved_true = true_label_;
-  Label* saved_false = false_label_;
+  // Always perform the comparison for its control flow.  Pack the result
+  // into the expression's context after the comparison is performed.
+  Label push_true, push_false, done;
+  // Initially assume we are in a test context.
+  Label* if_true = true_label_;
+  Label* if_false = false_label_;
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
-
     case Expression::kValue:
-      true_label_ = &push_true;
-      false_label_ = &push_false;
+      if_true = &push_true;
+      if_false = &push_false;
       break;
-
     case Expression::kEffect:
-      true_label_ = &done;
-      false_label_ = &done;
+      if_true = &done;
+      if_false = &done;
       break;
-
     case Expression::kTest:
       break;
-
     case Expression::kValueTest:
-      true_label_ = &push_true;
+      if_true = &push_true;
       break;
-
     case Expression::kTestValue:
-      false_label_ = &push_false;
+      if_false = &push_false;
       break;
   }
-  // Convert current context to test context: End pre-test code.
 
   switch (expr->op()) {
     case Token::IN: {
       __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION);
       __ CompareRoot(rax, Heap::kTrueValueRootIndex);
-      __ j(equal, true_label_);
-      __ jmp(false_label_);
+      __ j(equal, if_true);
+      __ jmp(if_false);
       break;
     }
 
@@ -1563,8 +1567,8 @@
       InstanceofStub stub;
       __ CallStub(&stub);
       __ testq(rax, rax);
-      __ j(zero, true_label_);  // The stub returns 0 for true.
-      __ jmp(false_label_);
+      __ j(zero, if_true);  // The stub returns 0 for true.
+      __ jmp(if_false);
       break;
     }
 
@@ -1574,7 +1578,7 @@
       switch (expr->op()) {
         case Token::EQ_STRICT:
           strict = true;
-          // Fall through
+          // Fall through.
         case Token::EQ:
           cc = equal;
           __ pop(rax);
@@ -1613,24 +1617,29 @@
       Label slow_case;
       __ JumpIfNotBothSmi(rax, rdx, &slow_case);
       __ SmiCompare(rdx, rax);
-      __ j(cc, true_label_);
-      __ jmp(false_label_);
+      __ j(cc, if_true);
+      __ jmp(if_false);
 
       __ bind(&slow_case);
       CompareStub stub(cc, strict);
       __ CallStub(&stub);
       __ testq(rax, rax);
-      __ j(cc, true_label_);
-      __ jmp(false_label_);
+      __ j(cc, if_true);
+      __ jmp(if_false);
     }
   }
 
-  // Convert current context to test context: Post-test code.
+  // Convert the result of the comparison into one expected for this
+  // expression's context.
   switch (expr->context()) {
     case Expression::kUninitialized:
       UNREACHABLE();
       break;
 
+    case Expression::kEffect:
+      __ bind(&done);
+      break;
+
     case Expression::kValue:
       __ bind(&push_true);
       __ PushRoot(Heap::kTrueValueRootIndex);
@@ -1640,34 +1649,27 @@
       __ bind(&done);
       break;
 
-    case Expression::kEffect:
-      __ bind(&done);
-      break;
-
     case Expression::kTest:
       break;
 
     case Expression::kValueTest:
       __ bind(&push_true);
       __ PushRoot(Heap::kTrueValueRootIndex);
-      __ jmp(saved_true);
+      __ jmp(true_label_);
       break;
 
     case Expression::kTestValue:
       __ bind(&push_false);
       __ PushRoot(Heap::kFalseValueRootIndex);
-      __ jmp(saved_false);
+      __ jmp(false_label_);
       break;
   }
-  true_label_ = saved_true;
-  false_label_ = saved_false;
-  // Convert current context to test context: End post-test code.
 }
 
 
 void FastCodeGenerator::VisitThisFunction(ThisFunction* expr) {
   __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
-  Move(expr->context(), rax);
+  Apply(expr->context(), rax);
 }
 
 
@@ -1722,11 +1724,6 @@
 }
 
 
-void FastCodeGenerator::ThrowException() {
-  __ push(result_register());
-  __ CallRuntime(Runtime::kThrow, 1);
-}
-
 #undef __
 
 
diff --git a/src/x64/ic-x64.cc b/src/x64/ic-x64.cc
index e240075..a0f87ad 100644
--- a/src/x64/ic-x64.cc
+++ b/src/x64/ic-x64.cc
@@ -330,6 +330,7 @@
 
   // Is the string a symbol?
   __ j(not_zero, &index_string);  // The value in rbx is used at jump target.
+  ASSERT(kSymbolTag != 0);
   __ testb(FieldOperand(rdx, Map::kInstanceTypeOffset),
            Immediate(kIsSymbolMask));
   __ j(zero, &slow);
@@ -408,6 +409,16 @@
 }
 
 
+void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- rsp[0] : return address
+  //  -- rsp[8] : name
+  //  -- rsp[16] : receiver
+  // -----------------------------------
+  GenerateGeneric(masm);
+}
+
+
 void KeyedLoadIC::GenerateExternalArray(MacroAssembler* masm,
                                         ExternalArrayType array_type) {
   // ----------- S t a t e -------------
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 9720005..37f96a6 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -38,6 +38,9 @@
 // function calling convention.
 static const Register kScratchRegister = r10;
 
+// Convenience for platform-independent signatures.
+typedef Operand MemOperand;
+
 // Forward declaration.
 class JumpTarget;
 
@@ -412,7 +415,11 @@
   void Cmp(Register dst, Handle<Object> source);
   void Cmp(const Operand& dst, Handle<Object> source);
   void Push(Handle<Object> source);
+
+  // Emit code to discard a non-negative number of pointer-sized elements
+  // from the stack, clobbering only the rsp register.
   void Drop(int stack_elements);
+
   void Call(Label* target) { call(target); }
 
   // Control Flow
diff --git a/src/x64/regexp-macro-assembler-x64.cc b/src/x64/regexp-macro-assembler-x64.cc
index 639f5e9..09cb917 100644
--- a/src/x64/regexp-macro-assembler-x64.cc
+++ b/src/x64/regexp-macro-assembler-x64.cc
@@ -60,20 +60,24 @@
  * - r8  : code object pointer. Used to convert between absolute and
  *         code-object-relative addresses.
  *
- * The registers rax, rbx, rcx, r9 and r11 are free to use for computations.
+ * The registers rax, rbx, r9 and r11 are free to use for computations.
  * If changed to use r12+, they should be saved as callee-save registers.
  *
  * Each call to a C++ method should retain these registers.
  *
  * The stack will have the following content, in some order, indexable from the
  * frame pointer (see, e.g., kStackHighEnd):
- *    - stack_area_base       (High end of the memory area to use as
- *                             backtracking stack)
- *    - at_start              (if 1, start at start of string, if 0, don't)
- *    - int* capture_array    (int[num_saved_registers_], for output).
- *    - end of input          (Address of end of string)
- *    - start of input        (Address of first character in string)
- *    - String** input_string (location of a handle containing the string)
+ *    - direct_call          (if 1, direct call from JavaScript code, if 0 call
+ *                            through the runtime system)
+ *    - stack_area_base      (High end of the memory area to use as
+ *                            backtracking stack)
+ *    - at_start             (if 1, we are starting at the start of the
+ *                            string, otherwise 0)
+ *    - int* capture_array   (int[num_saved_registers_], for output).
+ *    - end of input         (Address of end of string)
+ *    - start of input       (Address of first character in string)
+ *    - start index          (character index of start)
+ *    - String* input_string (input string)
  *    - return address
  *    - backup of callee save registers (rbx, possibly rsi and rdi).
  *    - Offset of location before start of input (effectively character
@@ -90,11 +94,13 @@
  * calling the code's entry address cast to a function pointer with the
  * following signature:
  * int (*match)(String* input_string,
+ *              int start_index,
  *              Address start,
  *              Address end,
  *              int* capture_output_array,
  *              bool at_start,
- *              byte* stack_area_base)
+ *              byte* stack_area_base,
+ *              bool direct_call)
  */
 
 #define __ ACCESS_MASM(masm_)
@@ -490,27 +496,22 @@
 
 
 bool RegExpMacroAssemblerX64::CheckSpecialCharacterClass(uc16 type,
-                                                         int cp_offset,
-                                                         bool check_offset,
                                                          Label* on_no_match) {
   // Range checks (c in min..max) are generally implemented by an unsigned
-  // (c - min) <= (max - min) check
+  // (c - min) <= (max - min) check, using the sequence:
+  //   lea(rax, Operand(current_character(), -min)) or sub(rax, Immediate(min))
+  //   cmp(rax, Immediate(max - min))
   switch (type) {
   case 's':
     // Match space-characters
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
-      if (check_offset) {
-        LoadCurrentCharacter(cp_offset, on_no_match);
-      } else {
-        LoadCurrentCharacterUnchecked(cp_offset, 1);
-      }
       Label success;
       __ cmpl(current_character(), Immediate(' '));
       __ j(equal, &success);
       // Check range 0x09..0x0d
-      __ subl(current_character(), Immediate('\t'));
-      __ cmpl(current_character(), Immediate('\r' - '\t'));
+      __ lea(rax, Operand(current_character(), -'\t'));
+      __ cmpl(rax, Immediate('\r' - '\t'));
       BranchOrBacktrack(above, on_no_match);
       __ bind(&success);
       return true;
@@ -518,72 +519,116 @@
     return false;
   case 'S':
     // Match non-space characters.
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
     if (mode_ == ASCII) {
       // ASCII space characters are '\t'..'\r' and ' '.
       __ cmpl(current_character(), Immediate(' '));
       BranchOrBacktrack(equal, on_no_match);
-      __ subl(current_character(), Immediate('\t'));
-      __ cmpl(current_character(), Immediate('\r' - '\t'));
+      __ lea(rax, Operand(current_character(), -'\t'));
+      __ cmpl(rax, Immediate('\r' - '\t'));
       BranchOrBacktrack(below_equal, on_no_match);
       return true;
     }
     return false;
   case 'd':
     // Match ASCII digits ('0'..'9')
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ subl(current_character(), Immediate('0'));
-    __ cmpl(current_character(), Immediate('9' - '0'));
+    __ lea(rax, Operand(current_character(), -'0'));
+    __ cmpl(rax, Immediate('9' - '0'));
     BranchOrBacktrack(above, on_no_match);
     return true;
   case 'D':
     // Match non ASCII-digits
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ subl(current_character(), Immediate('0'));
-    __ cmpl(current_character(), Immediate('9' - '0'));
+    __ lea(rax, Operand(current_character(), -'0'));
+    __ cmpl(rax, Immediate('9' - '0'));
     BranchOrBacktrack(below_equal, on_no_match);
     return true;
   case '.': {
     // Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
-    if (check_offset) {
-      LoadCurrentCharacter(cp_offset, on_no_match, 1);
-    } else {
-      LoadCurrentCharacterUnchecked(cp_offset, 1);
-    }
-    __ xor_(current_character(), Immediate(0x01));
+    __ movl(rax, current_character());
+    __ xor_(rax, Immediate(0x01));
     // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
-    __ subl(current_character(), Immediate(0x0b));
-    __ cmpl(current_character(), Immediate(0x0c - 0x0b));
+    __ subl(rax, Immediate(0x0b));
+    __ cmpl(rax, Immediate(0x0c - 0x0b));
     BranchOrBacktrack(below_equal, on_no_match);
     if (mode_ == UC16) {
       // Compare original value to 0x2028 and 0x2029, using the already
       // computed (current_char ^ 0x01 - 0x0b). I.e., check for
       // 0x201d (0x2028 - 0x0b) or 0x201e.
-      __ subl(current_character(), Immediate(0x2028 - 0x0b));
-      __ cmpl(current_character(), Immediate(1));
+      __ subl(rax, Immediate(0x2028 - 0x0b));
+      __ cmpl(rax, Immediate(0x2029 - 0x2028));
       BranchOrBacktrack(below_equal, on_no_match);
     }
     return true;
   }
-  case '*':
-    // Match any character.
-    if (check_offset) {
-      CheckPosition(cp_offset, on_no_match);
+  case 'n': {
+    // Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
+    __ movl(rax, current_character());
+    __ xor_(rax, Immediate(0x01));
+    // See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
+    __ subl(rax, Immediate(0x0b));
+    __ cmpl(rax, Immediate(0x0c - 0x0b));
+    if (mode_ == ASCII) {
+      BranchOrBacktrack(above, on_no_match);
+    } else {
+      Label done;
+      BranchOrBacktrack(below_equal, &done);
+      // Compare original value to 0x2028 and 0x2029, using the already
+      // computed (current_char ^ 0x01 - 0x0b). I.e., check for
+      // 0x201d (0x2028 - 0x0b) or 0x201e.
+      __ subl(rax, Immediate(0x2028 - 0x0b));
+      __ cmpl(rax, Immediate(0x2029 - 0x2028));
+      BranchOrBacktrack(above, on_no_match);
+      __ bind(&done);
     }
     return true;
-  // No custom implementation (yet): w, W, s(UC16), S(UC16).
+  }
+  case 'w': {
+    Label done, check_digits;
+    __ cmpl(current_character(), Immediate('9'));
+    __ j(less_equal, &check_digits);
+    __ cmpl(current_character(), Immediate('_'));
+    __ j(equal, &done);
+    // Convert to lower case if letter.
+    __ movl(rax, current_character());
+    __ orl(rax, Immediate(0x20));
+    // check rax in range ['a'..'z'].
+    __ subl(rax, Immediate('a'));
+    __ cmpl(rax, Immediate('z' - 'a'));
+    BranchOrBacktrack(above, on_no_match);
+    __ jmp(&done);
+    __ bind(&check_digits);
+    // Check current character in range ['0'..'9'].
+    __ cmpl(current_character(), Immediate('0'));
+    BranchOrBacktrack(below, on_no_match);
+    __ bind(&done);
+
+    return true;
+  }
+  case 'W': {
+    Label done, check_digits;
+    __ cmpl(current_character(), Immediate('9'));
+    __ j(less_equal, &check_digits);
+    __ cmpl(current_character(), Immediate('_'));
+    BranchOrBacktrack(equal, on_no_match);
+    // Convert to lower case if letter.
+    __ movl(rax, current_character());
+    __ orl(rax, Immediate(0x20));
+    // check current character in range ['a'..'z'], nondestructively.
+    __ subl(rax, Immediate('a'));
+    __ cmpl(rax, Immediate('z' - 'a'));
+    BranchOrBacktrack(below_equal, on_no_match);
+    __ jmp(&done);
+    __ bind(&check_digits);
+    // Check current character in range ['0'..'9'].
+    __ cmpl(current_character(), Immediate('0'));
+    BranchOrBacktrack(above_equal, on_no_match);
+    __ bind(&done);
+
+    return true;
+  }
+  case '*':
+    // Match any character.
+    return true;
+  // No custom implementation (yet): s(UC16), S(UC16).
   default:
     return false;
   }
diff --git a/src/x64/regexp-macro-assembler-x64.h b/src/x64/regexp-macro-assembler-x64.h
index 3e6720d..694cba0 100644
--- a/src/x64/regexp-macro-assembler-x64.h
+++ b/src/x64/regexp-macro-assembler-x64.h
@@ -73,8 +73,6 @@
   // the end of the string.
   virtual void CheckPosition(int cp_offset, Label* on_outside_input);
   virtual bool CheckSpecialCharacterClass(uc16 type,
-                                          int cp_offset,
-                                          bool check_offset,
                                           Label* on_no_match);
   virtual void Fail();
   virtual Handle<Object> GetCode(Handle<String> source);
@@ -143,6 +141,8 @@
   // AtStart is passed as 32 bit int (values 0 or 1).
   static const int kAtStart = kRegisterOutput + kPointerSize;
   static const int kStackHighEnd = kAtStart + kPointerSize;
+  // DirectCall is passed as 32 bit int (values 0 or 1).
+  static const int kDirectCall = kStackHighEnd + kPointerSize;
 #else
   // In AMD64 ABI Calling Convention, the first six integer parameters
   // are passed as registers, and caller must allocate space on the stack
@@ -154,6 +154,7 @@
   static const int kRegisterOutput = kInputEnd - kPointerSize;
   static const int kAtStart = kRegisterOutput - kPointerSize;
   static const int kStackHighEnd = kFrameAlign;
+  static const int kDirectCall = kStackHighEnd + kPointerSize;
 #endif
 
 #ifdef _WIN64
diff --git a/src/x64/simulator-x64.h b/src/x64/simulator-x64.h
index c4f3a85..015ba13 100644
--- a/src/x64/simulator-x64.h
+++ b/src/x64/simulator-x64.h
@@ -53,9 +53,9 @@
 };
 
 // Call the generated regexp code directly. The entry function pointer should
-// expect seven int/pointer sized arguments and return an int.
-#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
-  entry(p0, p1, p2, p3, p4, p5, p6)
+// expect eight int/pointer sized arguments and return an int.
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6, p7) \
+  entry(p0, p1, p2, p3, p4, p5, p6, p7)
 
 #define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
   reinterpret_cast<TryCatch*>(try_catch_address)
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 32bd345..cbddb61 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -1827,17 +1827,15 @@
   // depending on the this.x = ...; assignment in the function.
   for (int i = 0; i < shared->this_property_assignments_count(); i++) {
     if (shared->IsThisPropertyAssignmentArgument(i)) {
-      Label not_passed;
-      // Set the property to undefined.
-      __ movq(Operand(r9, i * kPointerSize), r8);
       // Check if the argument assigned to the property is actually passed.
+      // If argument is not passed the property is set to undefined,
+      // otherwise find it on the stack.
       int arg_number = shared->GetThisPropertyAssignmentArgument(i);
+      __ movq(rbx, r8);
       __ cmpq(rax, Immediate(arg_number));
-      __ j(below_equal, &not_passed);
-      // Argument passed - find it on the stack.
-      __ movq(rbx, Operand(rcx, arg_number * -kPointerSize));
+      __ cmovq(above, rbx, Operand(rcx, arg_number * -kPointerSize));
+      // Store value in the property.
       __ movq(Operand(r9, i * kPointerSize), rbx);
-      __ bind(&not_passed);
     } else {
       // Set the property to the constant value.
       Handle<Object> constant(shared->GetThisPropertyAssignmentConstant(i));
diff --git a/src/x64/virtual-frame-x64.cc b/src/x64/virtual-frame-x64.cc
index fe65d34..6e84ed1 100644
--- a/src/x64/virtual-frame-x64.cc
+++ b/src/x64/virtual-frame-x64.cc
@@ -129,11 +129,29 @@
     Handle<Object> undefined = Factory::undefined_value();
     FrameElement initial_value =
         FrameElement::ConstantElement(undefined, FrameElement::SYNCED);
-    __ movq(kScratchRegister, undefined, RelocInfo::EMBEDDED_OBJECT);
+    if (count == 1) {
+      __ Push(undefined);
+    } else if (count < kLocalVarBound) {
+      // For less locals the unrolled loop is more compact.
+      __ movq(kScratchRegister, undefined, RelocInfo::EMBEDDED_OBJECT);
+      for (int i = 0; i < count; i++) {
+        __ push(kScratchRegister);
+      }
+    } else {
+      // For more locals a loop in generated code is more compact.
+      Label alloc_locals_loop;
+      Result cnt = cgen()->allocator()->Allocate();
+      ASSERT(cnt.is_valid());
+      __ movq(cnt.reg(), Immediate(count));
+      __ movq(kScratchRegister, undefined, RelocInfo::EMBEDDED_OBJECT);
+      __ bind(&alloc_locals_loop);
+      __ push(kScratchRegister);
+      __ decl(cnt.reg());
+      __ j(not_zero, &alloc_locals_loop);
+    }
     for (int i = 0; i < count; i++) {
       elements_.Add(initial_value);
       stack_pointer_++;
-      __ push(kScratchRegister);
     }
   }
 }
diff --git a/src/x64/virtual-frame-x64.h b/src/x64/virtual-frame-x64.h
index e492305..88cf2bca 100644
--- a/src/x64/virtual-frame-x64.h
+++ b/src/x64/virtual-frame-x64.h
@@ -200,6 +200,9 @@
   // shared return site.  Emits code for spills.
   void PrepareForReturn();
 
+  // Number of local variables after when we use a loop for allocating.
+  static const int kLocalVarBound = 7;
+
   // Allocate and initialize the frame-allocated locals.
   void AllocateStackSlots();
 
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 3e3c957..3db7c37 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -6742,6 +6742,27 @@
       v8::ScriptData::PreCompile(script, i::StrLength(script));
   CHECK_NE(sd->Length(), 0);
   CHECK_NE(sd->Data(), NULL);
+  CHECK(!sd->HasError());
+  delete sd;
+}
+
+
+TEST(PreCompileWithError) {
+  v8::V8::Initialize();
+  const char *script = "function foo(a) { return 1 * * 2; }";
+  v8::ScriptData *sd =
+      v8::ScriptData::PreCompile(script, i::StrLength(script));
+  CHECK(sd->HasError());
+  delete sd;
+}
+
+
+TEST(Regress31661) {
+  v8::V8::Initialize();
+  const char *script = " The Definintive Guide";
+  v8::ScriptData *sd =
+      v8::ScriptData::PreCompile(script, i::StrLength(script));
+  CHECK(sd->HasError());
   delete sd;
 }
 
diff --git a/test/cctest/test-disasm-ia32.cc b/test/cctest/test-disasm-ia32.cc
index b8b3364..ba4eec2 100644
--- a/test/cctest/test-disasm-ia32.cc
+++ b/test/cctest/test-disasm-ia32.cc
@@ -57,7 +57,7 @@
 TEST(DisasmIa320) {
   InitializeVM();
   v8::HandleScope scope;
-  v8::internal::byte buffer[1024];
+  v8::internal::byte buffer[2048];
   Assembler assm(buffer, sizeof buffer);
   DummyStaticFunction(NULL);  // just bloody use it (DELETE; debugging)
 
@@ -223,13 +223,16 @@
 
   __ sub(Operand(ebx), Immediate(12));
   __ sub(Operand(edx, ecx, times_4, 10000), Immediate(12));
+  __ subb(Operand(edx, ecx, times_4, 10000), 100);
+  __ subb(Operand(eax), 100);
+  __ subb(eax, Operand(edx, ecx, times_4, 10000));
 
   __ xor_(ebx, 12345);
 
   __ imul(edx, ecx, 12);
   __ imul(edx, ecx, 1000);
 
-
+  __ rep_movs();
 
   __ sub(edx, Operand(ebx, ecx, times_4, 10000));
   __ sub(edx, Operand(ebx));
@@ -365,6 +368,12 @@
     __ movdbl(xmm1, Operand(ebx, ecx, times_4, 10000));
     __ movdbl(Operand(ebx, ecx, times_4, 10000), xmm1);
     __ comisd(xmm0, xmm1);
+
+    // 128 bit move instructions.
+    __ movdqa(xmm0, Operand(ebx, ecx, times_4, 10000));
+    __ movdqa(Operand(ebx, ecx, times_4, 10000), xmm0);
+    __ movdqu(xmm0, Operand(ebx, ecx, times_4, 10000));
+    __ movdqu(Operand(ebx, ecx, times_4, 10000), xmm0);
   }
 
   // cmov.
diff --git a/test/cctest/test-regexp.cc b/test/cctest/test-regexp.cc
index 6aa0730..c72c4d1 100644
--- a/test/cctest/test-regexp.cc
+++ b/test/cctest/test-regexp.cc
@@ -58,6 +58,16 @@
 using namespace v8::internal;
 
 
+static bool CheckParse(const char* input) {
+  V8::Initialize(NULL);
+  v8::HandleScope scope;
+  ZoneScope zone_scope(DELETE_ON_EXIT);
+  FlatStringReader reader(CStrVector(input));
+  RegExpCompileData result;
+  return v8::internal::ParseRegExp(&reader, false, &result);
+}
+
+
 static SmartPointer<const char> Parse(const char* input) {
   V8::Initialize(NULL);
   v8::HandleScope scope;
@@ -106,7 +116,7 @@
 }
 
 
-
+#define CHECK_PARSE_ERROR(input) CHECK(!CheckParse(input))
 #define CHECK_PARSE_EQ(input, expected) CHECK_EQ(expected, *Parse(input))
 #define CHECK_SIMPLE(input, simple) CHECK_EQ(simple, CheckSimple(input));
 #define CHECK_MIN_MAX(input, min, max)                                         \
@@ -117,6 +127,9 @@
 
 TEST(Parser) {
   V8::Initialize(NULL);
+
+  CHECK_PARSE_ERROR("?");
+
   CHECK_PARSE_EQ("abc", "'abc'");
   CHECK_PARSE_EQ("", "%");
   CHECK_PARSE_EQ("abc|def", "(| 'abc' 'def')");
@@ -600,6 +613,34 @@
   }
 }
 
+// Test of debug-only syntax.
+#ifdef DEBUG
+
+TEST(ParsePossessiveRepetition) {
+  bool old_flag_value = FLAG_regexp_possessive_quantifier;
+
+  // Enable possessive quantifier syntax.
+  FLAG_regexp_possessive_quantifier = true;
+
+  CHECK_PARSE_EQ("a*+", "(# 0 - p 'a')");
+  CHECK_PARSE_EQ("a++", "(# 1 - p 'a')");
+  CHECK_PARSE_EQ("a?+", "(# 0 1 p 'a')");
+  CHECK_PARSE_EQ("a{10,20}+", "(# 10 20 p 'a')");
+  CHECK_PARSE_EQ("za{10,20}+b", "(: 'z' (# 10 20 p 'a') 'b')");
+
+  // Disable possessive quantifier syntax.
+  FLAG_regexp_possessive_quantifier = false;
+
+  CHECK_PARSE_ERROR("a*+");
+  CHECK_PARSE_ERROR("a++");
+  CHECK_PARSE_ERROR("a?+");
+  CHECK_PARSE_ERROR("a{10,20}+");
+  CHECK_PARSE_ERROR("a{10,20}+b");
+
+  FLAG_regexp_possessive_quantifier = old_flag_value;
+}
+
+#endif
 
 // Tests of interpreter.
 
@@ -1550,7 +1591,68 @@
 }
 
 
+TEST(CanonicalizeCharacterSets) {
+  ZoneScope scope(DELETE_ON_EXIT);
+  ZoneList<CharacterRange>* list = new ZoneList<CharacterRange>(4);
+  CharacterSet set(list);
+
+  list->Add(CharacterRange(10, 20));
+  list->Add(CharacterRange(30, 40));
+  list->Add(CharacterRange(50, 60));
+  set.Canonicalize();
+  ASSERT_EQ(3, list->length());
+  ASSERT_EQ(10, list->at(0).from());
+  ASSERT_EQ(20, list->at(0).to());
+  ASSERT_EQ(30, list->at(1).from());
+  ASSERT_EQ(40, list->at(1).to());
+  ASSERT_EQ(50, list->at(2).from());
+  ASSERT_EQ(60, list->at(2).to());
+
+  list->Rewind(0);
+  list->Add(CharacterRange(10, 20));
+  list->Add(CharacterRange(50, 60));
+  list->Add(CharacterRange(30, 40));
+  set.Canonicalize();
+  ASSERT_EQ(3, list->length());
+  ASSERT_EQ(10, list->at(0).from());
+  ASSERT_EQ(20, list->at(0).to());
+  ASSERT_EQ(30, list->at(1).from());
+  ASSERT_EQ(40, list->at(1).to());
+  ASSERT_EQ(50, list->at(2).from());
+  ASSERT_EQ(60, list->at(2).to());
+
+  list->Rewind(0);
+  list->Add(CharacterRange(30, 40));
+  list->Add(CharacterRange(10, 20));
+  list->Add(CharacterRange(25, 25));
+  list->Add(CharacterRange(100, 100));
+  list->Add(CharacterRange(1, 1));
+  set.Canonicalize();
+  ASSERT_EQ(5, list->length());
+  ASSERT_EQ(1, list->at(0).from());
+  ASSERT_EQ(1, list->at(0).to());
+  ASSERT_EQ(10, list->at(1).from());
+  ASSERT_EQ(20, list->at(1).to());
+  ASSERT_EQ(25, list->at(2).from());
+  ASSERT_EQ(25, list->at(2).to());
+  ASSERT_EQ(30, list->at(3).from());
+  ASSERT_EQ(40, list->at(3).to());
+  ASSERT_EQ(100, list->at(4).from());
+  ASSERT_EQ(100, list->at(4).to());
+
+  list->Rewind(0);
+  list->Add(CharacterRange(10, 19));
+  list->Add(CharacterRange(21, 30));
+  list->Add(CharacterRange(20, 20));
+  set.Canonicalize();
+  ASSERT_EQ(1, list->length());
+  ASSERT_EQ(10, list->at(0).from());
+  ASSERT_EQ(30, list->at(0).to());
+}
+
+
+
 TEST(Graph) {
   V8::Initialize(NULL);
-  Execute("(?:(?:x(.))?\1)+$", false, true, true);
+  Execute("\\b\\w+\\b", false, true, true);
 }
diff --git a/test/cctest/test-serialize.cc b/test/cctest/test-serialize.cc
index 8f4441a..d02972b 100644
--- a/test/cctest/test-serialize.cc
+++ b/test/cctest/test-serialize.cc
@@ -37,6 +37,8 @@
 #include "scopeinfo.h"
 #include "snapshot.h"
 #include "cctest.h"
+#include "spaces.h"
+#include "objects.h"
 
 using namespace v8::internal;
 
@@ -277,6 +279,149 @@
 }
 
 
+class FileByteSink : public SnapshotByteSink {
+ public:
+  explicit FileByteSink(const char* snapshot_file) {
+    fp_ = OS::FOpen(snapshot_file, "wb");
+    if (fp_ == NULL) {
+      PrintF("Unable to write to snapshot file \"%s\"\n", snapshot_file);
+      exit(1);
+    }
+  }
+  virtual ~FileByteSink() {
+    if (fp_ != NULL) {
+      fclose(fp_);
+    }
+  }
+  virtual void Put(int byte, const char* description) {
+    if (fp_ != NULL) {
+      fputc(byte, fp_);
+    }
+  }
+
+ private:
+  FILE* fp_;
+};
+
+
+TEST(PartialSerialization) {
+  Serializer::Enable();
+  v8::V8::Initialize();
+  v8::Persistent<v8::Context> env = v8::Context::New();
+  env->Enter();
+
+  v8::HandleScope handle_scope;
+  v8::Local<v8::String> foo = v8::String::New("foo");
+
+  FileByteSink file(FLAG_testing_serialization_file);
+  Serializer ser(&file);
+  i::Handle<i::String> internal_foo = v8::Utils::OpenHandle(*foo);
+  Object* raw_foo = *internal_foo;
+  ser.SerializePartial(&raw_foo);
+}
+
+
+TEST(LinearAllocation) {
+  v8::V8::Initialize();
+  int new_space_max = 512 * KB;
+  for (int size = 1000; size < 5 * MB; size += size >> 1) {
+    int new_space_size = (size < new_space_max) ? size : new_space_max;
+    Heap::ReserveSpace(
+        new_space_size,
+        size,              // Old pointer space.
+        size,              // Old data space.
+        size,              // Code space.
+        size,              // Map space.
+        size,              // Cell space.
+        size);             // Large object space.
+    LinearAllocationScope linear_allocation_scope;
+    const int kSmallFixedArrayLength = 4;
+    const int kSmallFixedArraySize =
+        FixedArray::kHeaderSize + kSmallFixedArrayLength * kPointerSize;
+    const int kSmallStringLength = 16;
+    const int kSmallStringSize =
+        SeqAsciiString::kHeaderSize + kSmallStringLength;
+    const int kMapSize = Map::kSize;
+
+    Object* new_last = NULL;
+    for (int i = 0;
+         i + kSmallFixedArraySize <= new_space_size;
+         i += kSmallFixedArraySize) {
+      Object* obj = Heap::AllocateFixedArray(kSmallFixedArrayLength);
+      if (new_last != NULL) {
+        CHECK_EQ(reinterpret_cast<char*>(obj),
+                 reinterpret_cast<char*>(new_last) + kSmallFixedArraySize);
+      }
+      new_last = obj;
+    }
+
+    Object* pointer_last = NULL;
+    for (int i = 0;
+         i + kSmallFixedArraySize <= size;
+         i += kSmallFixedArraySize) {
+      Object* obj = Heap::AllocateFixedArray(kSmallFixedArrayLength, TENURED);
+      int old_page_fullness = i % Page::kPageSize;
+      int page_fullness = (i + kSmallFixedArraySize) % Page::kPageSize;
+      if (page_fullness < old_page_fullness ||
+          page_fullness > Page::kObjectAreaSize) {
+        i = RoundUp(i, Page::kPageSize);
+        pointer_last = NULL;
+      }
+      if (pointer_last != NULL) {
+        CHECK_EQ(reinterpret_cast<char*>(obj),
+                 reinterpret_cast<char*>(pointer_last) + kSmallFixedArraySize);
+      }
+      pointer_last = obj;
+    }
+
+    Object* data_last = NULL;
+    for (int i = 0; i + kSmallStringSize <= size; i += kSmallStringSize) {
+      Object* obj = Heap::AllocateRawAsciiString(kSmallStringLength, TENURED);
+      int old_page_fullness = i % Page::kPageSize;
+      int page_fullness = (i + kSmallStringSize) % Page::kPageSize;
+      if (page_fullness < old_page_fullness ||
+          page_fullness > Page::kObjectAreaSize) {
+        i = RoundUp(i, Page::kPageSize);
+        data_last = NULL;
+      }
+      if (data_last != NULL) {
+        CHECK_EQ(reinterpret_cast<char*>(obj),
+                 reinterpret_cast<char*>(data_last) + kSmallStringSize);
+      }
+      data_last = obj;
+    }
+
+    Object* map_last = NULL;
+    for (int i = 0; i + kMapSize <= size; i += kMapSize) {
+      Object* obj = Heap::AllocateMap(JS_OBJECT_TYPE, 42 * kPointerSize);
+      int old_page_fullness = i % Page::kPageSize;
+      int page_fullness = (i + kMapSize) % Page::kPageSize;
+      if (page_fullness < old_page_fullness ||
+          page_fullness > Page::kObjectAreaSize) {
+        i = RoundUp(i, Page::kPageSize);
+        map_last = NULL;
+      }
+      if (map_last != NULL) {
+        CHECK_EQ(reinterpret_cast<char*>(obj),
+                 reinterpret_cast<char*>(map_last) + kMapSize);
+      }
+      map_last = obj;
+    }
+
+    if (size > Page::kObjectAreaSize) {
+      // Support for reserving space in large object space is not there yet,
+      // but using an always-allocate scope is fine for now.
+      AlwaysAllocateScope always;
+      int large_object_array_length =
+          (size - FixedArray::kHeaderSize) / kPointerSize;
+      Object* obj = Heap::AllocateFixedArray(large_object_array_length,
+                                             TENURED);
+      CHECK(!obj->IsFailure());
+    }
+  }
+}
+
+
 TEST(TestThatAlwaysSucceeds) {
 }
 
diff --git a/test/es5conform/es5conform.status b/test/es5conform/es5conform.status
index 49cffb2..3fc1e0a 100644
--- a/test/es5conform/es5conform.status
+++ b/test/es5conform/es5conform.status
@@ -38,8 +38,6 @@
 chapter14: UNIMPLEMENTED
 chapter15/15.1: UNIMPLEMENTED
 chapter15/15.2/15.2.3/15.2.3.1: UNIMPLEMENTED
-chapter15/15.2/15.2.3/15.2.3.2: UNIMPLEMENTED
-chapter15/15.2/15.2.3/15.2.3.3: UNIMPLEMENTED
 chapter15/15.2/15.2.3/15.2.3.4: UNIMPLEMENTED
 chapter15/15.2/15.2.3/15.2.3.5: UNIMPLEMENTED
 chapter15/15.2/15.2.3/15.2.3.6: UNIMPLEMENTED
@@ -51,6 +49,99 @@
 chapter15/15.2/15.2.3/15.2.3.12: UNIMPLEMENTED
 chapter15/15.2/15.2.3/15.2.3.13: UNIMPLEMENTED
 
+# Object.getPrototypeOf
+chapter15/15.2/15.2.3/15.2.3.2: PASS
+
+# Object.getOwnPropertyDescriptor
+chapter15/15.2/15.2.3/15.2.3.3: PASS
+
+# NOT IMPLEMENTED: defineProperty
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-3: FAIL_OK
+
+# NOT IMPLEMENTED: getOwnPropertyNames
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-16: FAIL_OK
+
+# NOT IMPLEMENTED: defineProperty
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-18: FAIL_OK
+
+# NOT IMPLEMENTED: defineProperties
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-19: FAIL_OK
+
+# NOT IMPLEMENTED: seal
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-20: FAIL_OK
+
+# NOT IMPLEMENTED: freeze
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-21: FAIL_OK
+
+# NOT IMPLEMENTED: preventExtensions
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-22: FAIL_OK
+
+# NOT IMPLEMENTED: isSealed
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-23: FAIL_OK
+
+# NOT IMPLEMENTED: isFrozen
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-24: FAIL_OK
+
+# NOT IMPLEMENTED: isExtensible
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-25: FAIL_OK
+
+# NOT IMPLEMENTED: bind
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-38: FAIL_OK
+
+# Built-ins have wrong descriptor (should all be false)
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-178: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-179: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-180: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-182: FAIL_OK
+
+# Our Function object has a "arguments" property which is used as a non
+# property in in the test
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-183: FAIL_OK
+
+
+# Our Function object has a "caller" property which is used as a non
+# property in in the test
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-184: FAIL_OK
+
+# Built-ins have wrong descriptor (should all be false)
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-185: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-186: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-187: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-188: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-189: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-190: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-191: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-192: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-193: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-194: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-195: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-201: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-210: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-211: FAIL_OK
+
+
+# NOT IMPLEMENTED: RegExp.prototype.source
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-212: FAIL_OK
+
+# NOT IMPLEMENTED: RegExp.prototype.global
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-213: FAIL_OK
+
+# NOT IMPLEMENTED: RegExp.prototype.ignoreCase
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-214: FAIL_OK
+
+# NOT IMPLEMENTED: RegExp.prototype.multiline
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-215: FAIL_OK
+
+# Errors have wrong descriptor (should all be false)
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-216: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-217: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-218: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-219: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-220: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-221: FAIL_OK
+chapter15/15.2/15.2.3/15.2.3.3/15.2.3.3-4-222: FAIL_OK
+
+
 # Object.keys
 chapter15/15.2/15.2.3/15.2.3.14: PASS
 
@@ -59,7 +150,74 @@
 chapter15/15.2/15.2.3/15.2.3.14/15.2.3.14-3-3: FAIL_OK
 
 chapter15/15.3: UNIMPLEMENTED
-chapter15/15.4: UNIMPLEMENTED
+
+chapter15/15.4/15.4.4/15.4.4.14: UNIMPLEMENTED
+chapter15/15.4/15.4.4/15.4.4.15: UNIMPLEMENTED
+chapter15/15.4/15.4.4/15.4.4.20: UNIMPLEMENTED
+chapter15/15.4/15.4.4/15.4.4.21: UNIMPLEMENTED
+chapter15/15.4/15.4.4/15.4.4.22: UNIMPLEMENTED
+
+# Array.prototype.every
+chapter15/15.4/15.4.4/15.4.4.16: PASS
+
+# Wrong test - because this is not given as argument to arr.every
+# this._15_4_4_16_5_1 evaluates to undefined
+chapter15/15.4/15.4.4/15.4.4.16/15.4.4.16-5-1: FAIL_OK
+
+# In test case the element is not appended - it is added in the middle of 
+# the array
+chapter15/15.4/15.4.4/15.4.4.16/15.4.4.16-7-1: FAIL_OK
+
+# We fail because the test assumes that if the reference to array is deleted it
+# is not longer traversed
+chapter15/15.4/15.4.4/15.4.4.16/15.4.4.16-7-7: FAIL_OK
+
+# if (val>1) in test should be if (val>2)
+chapter15/15.4/15.4.4/15.4.4.16/15.4.4.16-8-10: FAIL_OK
+
+
+# Array.prototype.some
+chapter15/15.4/15.4.4/15.4.4.17: PASS
+
+# Wrong assumption - according to spec some returns a Boolean, not a number
+chapter15/15.4/15.4.4/15.4.4.17/15.4.4.17-4-9: FAIL_OK
+
+# Same as 15.4.4.16-5-1
+chapter15/15.4/15.4.4/15.4.4.17/15.4.4.17-5-1: FAIL_OK
+
+# Same as 15.4.4.16-7-1
+chapter15/15.4/15.4.4/15.4.4.17/15.4.4.17-7-1: FAIL_OK
+
+# Same as 15.4.4.16-7-7
+chapter15/15.4/15.4.4/15.4.4.17/15.4.4.17-7-7: FAIL_OK
+
+# Same as 15.4.4.16-10-8
+chapter15/15.4/15.4.4/15.4.4.17/15.4.4.17-8-10: FAIL_OK
+
+
+# Array.prototype.forEach
+chapter15/15.4/15.4.4/15.4.4.18: PASS
+
+# Same as 15.4.4.16-5-1
+chapter15/15.4/15.4.4/15.4.4.18/15.4.4.18-5-1: FAIL_OK
+
+# Same as 15.4.4.16-7-7
+chapter15/15.4/15.4.4/15.4.4.18/15.4.4.18-7-6: FAIL_OK
+
+
+# Array.prototype.map
+chapter15/15.4/15.4.4/15.4.4.19: PASS
+
+# Same as 15.4.4.16-5-1
+chapter15/15.4/15.4.4/15.4.4.19/15.4.4.19-5-1: FAIL_OK
+
+# Same as 15.4.4.16-7-7
+chapter15/15.4/15.4.4/15.4.4.19/15.4.4.19-8-7: FAIL_OK
+
+# Uses a array index number as a property
+chapter15/15.4/15.4.4/15.4.4.19/15.4.4.19-8-c-iii-1: FAIL_OK
+
+
 chapter15/15.5: UNIMPLEMENTED
 chapter15/15.6: UNIMPLEMENTED
 chapter15/15.7: UNIMPLEMENTED
diff --git a/test/mjsunit/bit-not.js b/test/mjsunit/bit-not.js
new file mode 100644
index 0000000..85eccc4
--- /dev/null
+++ b/test/mjsunit/bit-not.js
@@ -0,0 +1,75 @@
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function testBitNot(x, name) {
+  // The VM constant folds so we use that to check the result.
+  var expected = eval("~(" + x + ")");
+  var actual = ~x;
+  assertEquals(expected, actual, "x: " + name);
+
+  // Test the path where we can overwrite the result. Use -
+  // to avoid concatenating strings.
+  expected = eval("~(" + x + " - 0.01)");
+  actual = ~(x - 0.01);
+  assertEquals(expected, actual, "x - 0.01: " + name);
+}
+
+
+testBitNot(0, 0);
+testBitNot(1, 1);
+testBitNot(-1, 1);
+testBitNot(100, 100);
+testBitNot(0x40000000, "0x40000000");
+testBitNot(0x7fffffff, "0x7fffffff");
+testBitNot(0x80000000, "0x80000000");
+
+testBitNot(2.2, 2.2);
+testBitNot(-2.3, -2.3);
+testBitNot(Infinity, "Infinity");
+testBitNot(NaN, "NaN");
+testBitNot(-Infinity, "-Infinity");
+testBitNot(0x40000000 + 0.12345, "float1");
+testBitNot(0x40000000 - 0.12345, "float2");
+testBitNot(0x7fffffff + 0.12345, "float3");
+testBitNot(0x7fffffff - 0.12345, "float4");
+testBitNot(0x80000000 + 0.12345, "float5");
+testBitNot(0x80000000 - 0.12345, "float6");
+
+testBitNot("0", "string0");
+testBitNot("2.3", "string2.3");
+testBitNot("-9.4", "string-9.4");
+
+
+// Try to test that we can deal with allocation failures in
+// the fast path and just use the slow path instead.
+function TryToGC() {
+  var x = 0x40000000;
+  for (var i = 0; i < 1000000; i++) {
+    assertEquals(~0x40000000, ~x);
+  }
+}
+TryToGC();
diff --git a/test/mjsunit/bitwise-operations-undefined.js b/test/mjsunit/bitwise-operations-undefined.js
new file mode 100644
index 0000000..716e52d
--- /dev/null
+++ b/test/mjsunit/bitwise-operations-undefined.js
@@ -0,0 +1,49 @@
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test bitwise operations with undefined.
+
+function testUndefinedLeftHandSide() {
+  assertEquals(undefined | 1, 1);
+  assertEquals(undefined & 1, 0);
+  assertEquals(undefined ^ 1, 1);
+  assertEquals(undefined << 1, 0);
+  assertEquals(undefined >> 1, 0);
+  assertEquals(undefined >>> 1, 0);
+}
+
+function testUndefinedRightHandSide() {
+  assertEquals(1 | undefined, 1);
+  assertEquals(1 & undefined, 0);
+  assertEquals(1 ^ undefined, 1);
+  assertEquals(1 << undefined, 1);
+  assertEquals(1 >> undefined, 1);
+  assertEquals(1 >>> undefined, 1);
+}
+
+testUndefinedLeftHandSide();
+testUndefinedRightHandSide();
diff --git a/test/mjsunit/compare-character.js b/test/mjsunit/compare-character.js
new file mode 100644
index 0000000..cabe013
--- /dev/null
+++ b/test/mjsunit/compare-character.js
@@ -0,0 +1,50 @@
+// Copyright 2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test the optimized implementation of comparison with single-character
+// strings.
+
+var a = ['', String.fromCharCode(0), ' ', 'e', 'erik', 'f', 'foo', 'g', 'goo',
+         -1, 0, 1, 1.2, -7.9, true, false, 'foo', '0', 'NaN' ];
+for (var i in a) {
+  var x = a[i];
+  var f = 'f';
+
+  assertEquals(x == f, x == 'f', "==" + x);
+  assertEquals(x === f, x === 'f', "===" + x);
+  assertEquals(x < f, x < 'f', "<" + x);
+  assertEquals(x <= f, x <= 'f', "<=" + x);
+  assertEquals(x > f, x > 'f', ">" + x);
+  assertEquals(x >= f, x >= 'f', ">=" + x);
+  assertEquals(f == x, 'f' == x, "==r" + x);
+  assertEquals(f === x, 'f' === x, "===r" + x);
+  assertEquals(f > x, 'f' > x, "<r" + x);
+  assertEquals(f >= x, 'f' >= x, "<=r" + x);
+  assertEquals(f < x, 'f' < x, ">r" + x);
+  assertEquals(f <= x, 'f' <= x, ">=r" + x);
+}
+
diff --git a/test/mjsunit/compare-nan.js b/test/mjsunit/compare-nan.js
index fc40acc..c4f7817 100644
--- a/test/mjsunit/compare-nan.js
+++ b/test/mjsunit/compare-nan.js
@@ -42,3 +42,25 @@
   assertFalse(x <= NaN, "" + x + " <= NaN");
   assertFalse(x >= NaN, "" + x + " >= NaN");
 }
+
+var b = ["NaN", "-1", "0", "1", "1.2", "-7.9", "true", "false", "'foo'", "'0'",
+         "'NaN'" ];
+for (var i in b) {
+  var x = b[i];
+  var program =
+      "assertFalse(NaN == " + x + ", 'NaN == ' + " + x + ");\n" +
+      "assertFalse(NaN === " + x + ", 'NaN === ' + " + x + ");\n" +
+      "assertFalse(NaN < " + x + ", 'NaN < ' + " + x + ");\n" +
+      "assertFalse(NaN > " + x + ", 'NaN > ' + " + x + ");\n" +
+      "assertFalse(NaN <= " + x + ", 'NaN <= ' + " + x + ");\n" +
+      "assertFalse(NaN >= " + x + ", 'NaN >= ' + " + x + ");\n" +
+
+      "assertFalse(" + x + " == NaN, '' + " + x + " + ' == NaN');\n" +
+      "assertFalse(" + x + " === NaN, '' + " + x + " + ' === NaN');\n" +
+      "assertFalse(" + x + " < NaN, '' + " + x + " + ' < NaN');\n" +
+      "assertFalse(" + x + " > NaN, '' + " + x + " + ' > NaN');\n" +
+      "assertFalse(" + x + " <= NaN, '' + " + x + " + ' <= NaN');\n" +
+      "assertFalse(" + x + " >= NaN, '' + " + x + " + ' >= NaN');\n";
+  eval(program);
+}
+
diff --git a/test/mjsunit/compiler/countoperation.js b/test/mjsunit/compiler/countoperation.js
new file mode 100644
index 0000000..5660cee
--- /dev/null
+++ b/test/mjsunit/compiler/countoperation.js
@@ -0,0 +1,111 @@
+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test pre- and postfix count operations.
+
+// Test value context.
+var a = 42;
+var b = {x:42};
+var c = "x";
+assertEquals(43, ++a);
+assertEquals(43, a);
+assertEquals(43, a++);
+assertEquals(44, a);
+assertEquals(43, ++b.x);
+assertEquals(43, b.x);
+assertEquals(43, b.x++);
+assertEquals(44, b.x);
+assertEquals(45, ++b[c]);
+assertEquals(45, b[c]);
+assertEquals(45, b[c]++);
+assertEquals(46, b[c]);
+
+// Test effect context.
+a = 42;
+b = {x:42};
+c = "x";
+assertEquals(1, eval("++a; 1"));
+assertEquals(43, a);
+assertEquals(1, eval("a++; 1"));
+assertEquals(44, a);
+assertEquals(1, eval("++b.x; 1"));
+assertEquals(43, b.x);
+assertEquals(1, eval("b.x++; 1"));
+assertEquals(44, b.x);
+assertEquals(1, eval("++b[c]; 1"));
+assertEquals(45, b[c]);
+assertEquals(1, eval("b[c]++; 1"));
+assertEquals(46, b[c]);
+
+// Test test context.
+a = 42;
+b = {x:42};
+c = "x";
+assertEquals(1, (++a) ? 1 : 0);
+assertEquals(43, a);
+assertEquals(1, (a++) ? 1 : 0);
+assertEquals(44, a);
+assertEquals(1, (++b.x) ? 1 : 0);
+assertEquals(43, b.x);
+assertEquals(1, (b.x++) ? 1 : 0);
+assertEquals(44, b.x);
+assertEquals(1, (++b[c]) ? 1 : 0);
+assertEquals(45, b[c]);
+assertEquals(1, (b[c]++) ? 1 : 0);
+assertEquals(46, b[c]);
+
+// Test value/test and test/value contexts.
+a = 42;
+b = {x:42};
+c = "x";
+assertEquals(43, ++a || 1);
+assertEquals(43, a);
+assertEquals(43, a++ || 1);
+assertEquals(44, a);
+assertEquals(43, ++b.x || 1);
+assertEquals(43, b.x);
+assertEquals(43, (b.x++) || 1);
+assertEquals(44, b.x);
+assertEquals(45, ++b[c] || 1);
+assertEquals(45, b[c]);
+assertEquals(45, b[c]++ || 1);
+assertEquals(46, b[c]);
+a = 42;
+b = {x:42};
+c = "x";
+assertEquals(1, ++a && 1);
+assertEquals(43, a);
+assertEquals(1, a++ && 1);
+assertEquals(44, a);
+assertEquals(1, ++b.x && 1);
+assertEquals(43, b.x);
+assertEquals(1, (b.x++) && 1);
+assertEquals(44, b.x);
+assertEquals(1, ++b[c] && 1);
+assertEquals(45, b[c]);
+assertEquals(1, b[c]++ && 1);
+assertEquals(46, b[c]);
diff --git a/test/mjsunit/eval.js b/test/mjsunit/eval.js
index 08bd3d0..95357c7 100644
--- a/test/mjsunit/eval.js
+++ b/test/mjsunit/eval.js
@@ -58,16 +58,16 @@
 
 // Test that un-aliased eval reads from local context.
 foo = 0;
-result = 
+result =
   (function() {
     var foo = 2;
     return eval('foo');
   })();
 assertEquals(2, result);
 
-//Test that un-aliased eval writes to local context.
+// Test that un-aliased eval writes to local context.
 foo = 0;
-result = 
+result =
   (function() {
     var foo = 1;
     eval('foo = 2');
@@ -84,7 +84,7 @@
 // Test that aliased eval reads from global context.
 var e = eval;
 foo = 0;
-result = 
+result =
   (function() {
     var foo = 2;
     return e('foo');
@@ -105,7 +105,7 @@
 // Try to cheat the 'aliased eval' detection.
 var x = this;
 foo = 0;
-result = 
+result =
   (function() {
     var foo = 2;
     return x.eval('foo');
@@ -113,7 +113,7 @@
 assertEquals(0, result);
 
 foo = 0;
-result = 
+result =
   (function() {
     var eval = function(x) { return x; };
     var foo = eval(2);
@@ -128,8 +128,29 @@
   })();
 assertEquals(4, result);
 
+result =
+  (function() {
+    eval("var eval = function(s) { return this; }");
+    return eval("42");  // Should return the global object
+  })();
+assertEquals(this, result);
+
+result =
+  (function() {
+    var obj = { f: function(eval) { return eval("this"); } };
+    return obj.f(eval);
+  })();
+assertEquals(this, result);
+
+result =
+  (function() {
+    var obj = { f: function(eval) { arguments; return eval("this"); } };
+    return obj.f(eval);
+  })();
+assertEquals(this, result);
+
 eval = function(x) { return 2 * x; };
-result = 
+result =
   (function() {
     return (function() { return eval(2); })();
   })();
diff --git a/test/mjsunit/fuzz-natives.js b/test/mjsunit/fuzz-natives.js
index cd50667..d906eb8 100644
--- a/test/mjsunit/fuzz-natives.js
+++ b/test/mjsunit/fuzz-natives.js
@@ -95,7 +95,11 @@
 
 var knownProblems = {
   "Abort": true,
-  
+
+  // Avoid calling the concat operation, because weird lengths
+  // may lead to out-of-memory.
+  "StringBuilderConcat": true,
+
   // These functions use pseudo-stack-pointers and are not robust
   // to unexpected integer values.
   "DebugEvaluate": true,
@@ -114,7 +118,7 @@
   // the rest of the tests.
   "DisableAccessChecks": true,
   "EnableAccessChecks": true,
-  
+
   // These functions should not be callable as runtime functions.
   "NewContext": true,
   "NewArgumentsFast": true,
diff --git a/test/mjsunit/get-own-property-descriptor.js b/test/mjsunit/get-own-property-descriptor.js
new file mode 100644
index 0000000..79172c8
--- /dev/null
+++ b/test/mjsunit/get-own-property-descriptor.js
@@ -0,0 +1,51 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function get(){return x}
+function set(x){this.x=x};
+
+var obj = {x:1};
+obj.__defineGetter__("accessor", get);
+obj.__defineSetter__("accessor", set);
+
+
+var descIsData = Object.getOwnPropertyDescriptor(obj,'x');
+assertTrue(descIsData.enumerable);
+assertTrue(descIsData.writable);
+assertTrue(descIsData.configurable);
+
+var descIsAccessor = Object.getOwnPropertyDescriptor(obj, 'accessor');
+assertTrue(descIsAccessor.enumerable);
+assertTrue(descIsAccessor.configurable);
+assertTrue(descIsAccessor.get == get);
+assertTrue(descIsAccessor.set == set);
+
+var descIsNotData = Object.getOwnPropertyDescriptor(obj, 'not-x');
+assertTrue(descIsNotData == undefined);
+
+var descIsNotAccessor = Object.getOwnPropertyDescriptor(obj, 'not-accessor');
+assertTrue(descIsNotAccessor == undefined);
diff --git a/test/mjsunit/get-prototype-of.js b/test/mjsunit/get-prototype-of.js
new file mode 100644
index 0000000..6475bde
--- /dev/null
+++ b/test/mjsunit/get-prototype-of.js
@@ -0,0 +1,68 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+function TryGetPrototypeOfNonObject(x) {
+  var caught = 0;
+  try {
+      Object.getPrototypeOf(x);
+  } catch (e) {
+    caught = e;
+  }
+
+  assertTrue(caught instanceof TypeError);
+};
+
+function GetPrototypeOfObject(x) {
+  assertDoesNotThrow(Object.getPrototypeOf(x));
+  assertNotNull(Object.getPrototypeOf(x));
+  assertEquals(Object.getPrototypeOf(x), x.__proto__);
+}
+
+function F(){};
+
+// Non object
+var x = 10;
+
+// Object
+var y = new F();
+
+// Make sure that TypeError exceptions are thrown when non-objects are passed
+// as argument
+TryGetPrototypeOfNonObject(0);
+TryGetPrototypeOfNonObject(null);
+TryGetPrototypeOfNonObject('Testing');
+TryGetPrototypeOfNonObject(x);
+
+// Make sure the real objects have this method and that it returns the
+// actual prototype object. Also test for Functions and RegExp.
+GetPrototypeOfObject(this);
+GetPrototypeOfObject(y);
+GetPrototypeOfObject({x:5});
+GetPrototypeOfObject(F);
+GetPrototypeOfObject(RegExp);
+
diff --git a/test/mjsunit/json.js b/test/mjsunit/json.js
index bf44f78..35e1634 100644
--- a/test/mjsunit/json.js
+++ b/test/mjsunit/json.js
@@ -65,9 +65,9 @@
 GenericToJSONChecks(String, "x", "y");
 
 // Date toJSON
-assertEquals("1970-01-01T00:00:00Z", new Date(0).toJSON());
-assertEquals("1979-01-11T08:00:00Z", new Date("1979-01-11 08:00 GMT").toJSON());
-assertEquals("2005-05-05T05:05:05Z", new Date("2005-05-05 05:05:05 GMT").toJSON());
+assertEquals("1970-01-01T00:00:00.000Z", new Date(0).toJSON());
+assertEquals("1979-01-11T08:00:00.000Z", new Date("1979-01-11 08:00 GMT").toJSON());
+assertEquals("2005-05-05T05:05:05.000Z", new Date("2005-05-05 05:05:05 GMT").toJSON());
 var n1 = new Date(10000);
 n1.toISOString = function () { return "foo"; };
 assertEquals("foo", n1.toJSON());
diff --git a/test/mjsunit/mirror-date.js b/test/mjsunit/mirror-date.js
index 6b6a3ad..5c113de 100644
--- a/test/mjsunit/mirror-date.js
+++ b/test/mjsunit/mirror-date.js
@@ -57,7 +57,7 @@
 
 // Test Date values.
 testDateMirror(new Date(Date.parse("Dec 25, 1995 1:30 UTC")),
-               "1995-12-25T01:30:00Z");
+               "1995-12-25T01:30:00.000Z");
 d = new Date();
 d.setUTCFullYear(1967);
 d.setUTCMonth(0); // January.
@@ -66,10 +66,12 @@
 d.setUTCMinutes(22);
 d.setUTCSeconds(59);
 d.setUTCMilliseconds(0);
-testDateMirror(d, "1967-01-17T09:22:59Z");
+testDateMirror(d, "1967-01-17T09:22:59.000Z");
 d.setUTCMilliseconds(1);
-testDateMirror(d, "1967-01-17T09:22:59Z");
+testDateMirror(d, "1967-01-17T09:22:59.001Z");
 d.setUTCSeconds(12);
-testDateMirror(d, "1967-01-17T09:22:12Z");
+testDateMirror(d, "1967-01-17T09:22:12.001Z");
 d.setUTCSeconds(36);
-testDateMirror(d, "1967-01-17T09:22:36Z");
+testDateMirror(d, "1967-01-17T09:22:36.001Z");
+d.setUTCMilliseconds(136);
+testDateMirror(d, "1967-01-17T09:22:36.136Z");
diff --git a/test/mjsunit/smi-ops.js b/test/mjsunit/smi-ops.js
index 284050d..39b4894 100644
--- a/test/mjsunit/smi-ops.js
+++ b/test/mjsunit/smi-ops.js
@@ -537,7 +537,7 @@
   one = four - three;
   zero = one - one;
 
- // Begin block A repeat 3
+  // Begin block A repeat 3
   assertEquals(pos_non_smi, (pos_non_smi) >> zero);
   assertEquals(pos_non_smi, (pos_non_smi) >>> zero);
   assertEquals(pos_non_smi, (pos_non_smi) << zero);
@@ -638,6 +638,31 @@
 
 testShiftNonSmis();
 
+function intConversion() {
+  function foo(x) {
+    assertEquals(x, (x * 1.0000000001) | 0, "foo more " + x);
+    assertEquals(x, x | 0, "foo " + x);
+    if (x > 0) {
+      assertEquals(x - 1, (x * 0.9999999999) | 0, "foo less " + x);
+    } else {
+      assertEquals(x + 1, (x * 0.9999999999) | 0, "foo less " + x);
+    }
+  }
+  for (var i = 1; i < 0x80000000; i *= 2) {
+    foo(i);
+    foo(-i);
+  }
+  for (var i = 1; i < 1/0; i *= 2) {
+    assertEquals(i | 0, (i * 1.0000000000000001) | 0, "b" + i);
+    assertEquals(-i | 0, (i * -1.0000000000000001) | 0, "c" + i);
+  }
+  for (var i = 0.5; i > 0; i /= 2) {
+    assertEquals(0, i | 0, "d" + i);
+    assertEquals(0, -i | 0, "e" + i);
+  }
+}
+
+intConversion();
 
 // Verify that we handle the (optimized) corner case of shifting by
 // zero even for non-smis.
diff --git a/tools/gyp/v8.gyp b/tools/gyp/v8.gyp
index ba7224b..4368eb8 100644
--- a/tools/gyp/v8.gyp
+++ b/tools/gyp/v8.gyp
@@ -199,9 +199,7 @@
       'conditions': [
         # The ARM assembler assumes the host is 32 bits, so force building
         # 32-bit host tools.
-        # TODO(piman): This assumes that the host is ia32 or amd64. Fixing the
-        # code would be better
-        ['target_arch=="arm" and _toolset=="host"', {
+        ['target_arch=="arm" and host_arch=="x64" and _toolset=="host"', {
           'cflags': ['-m32'],
           'ldflags': ['-m32'],
         }]
@@ -428,9 +426,7 @@
           'conditions': [
             # The ARM assembler assumes the host is 32 bits, so force building
             # 32-bit host tools.
-            # TODO(piman): This assumes that the host is ia32 or amd64. Fixing
-            # the code would be better
-            ['_toolset=="host"', {
+            ['host_arch=="x64" and _toolset=="host"', {
               'cflags': ['-m32'],
               'ldflags': ['-m32'],
             }]
@@ -598,9 +594,7 @@
       'conditions': [
         # The ARM assembler assumes the host is 32 bits, so force building
         # 32-bit host tools.
-        # TODO(piman): This assumes that the host is ia32 or amd64. Fixing
-        # the code would be better
-        ['target_arch=="arm" and _toolset=="host"', {
+        ['target_arch=="arm" and host_arch=="x64" and _toolset=="host"', {
           'cflags': ['-m32'],
           'ldflags': ['-m32'],
         }]
diff --git a/tools/jsmin.py b/tools/jsmin.py
index fd1abe4..646bf14 100644
--- a/tools/jsmin.py
+++ b/tools/jsmin.py
@@ -230,7 +230,9 @@
       # A regexp that matches a literal string surrounded by 'double quotes'.
       single_quoted_string = r"'(?:[^'\\]|\\.)*'"
       # A regexp that matches a regexp literal surrounded by /slashes/.
-      slash_quoted_regexp = r"/(?:[^/\\]|\\.)+/"
+      # Don't allow a regexp to have a ) before the first ( since that's a
+      # syntax error and it's probably just two unrelated slashes.
+      slash_quoted_regexp = r"/(?:(?=\()|(?:[^()/\\]|\\.)+)(?:\([^/\\]|\\.)*/"
       # Replace multiple spaces with a single space.
       line = re.sub("|".join([double_quoted_string,
                               single_quoted_string,
diff --git a/tools/presubmit.py b/tools/presubmit.py
index 3f27c00..04952e0 100755
--- a/tools/presubmit.py
+++ b/tools/presubmit.py
@@ -221,7 +221,7 @@
 
 
 COPYRIGHT_HEADER_PATTERN = re.compile(
-    r'Copyright [\d-]*200[8-9] the V8 project authors. All rights reserved.')
+    r'Copyright [\d-]*20[0-1][0-9] the V8 project authors. All rights reserved.')
 
 class SourceProcessor(SourceFileProcessor):
   """