Move V8 to external/v8

Change-Id: If68025d67453785a651c5dfb34fad298c16676a4
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
new file mode 100644
index 0000000..38ada92
--- /dev/null
+++ b/src/x64/macro-assembler-x64.cc
@@ -0,0 +1,2186 @@
+// 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.
+
+#include "v8.h"
+
+#include "bootstrapper.h"
+#include "codegen-inl.h"
+#include "assembler-x64.h"
+#include "macro-assembler-x64.h"
+#include "serialize.h"
+#include "debug.h"
+
+namespace v8 {
+namespace internal {
+
+MacroAssembler::MacroAssembler(void* buffer, int size)
+  : Assembler(buffer, size),
+    unresolved_(0),
+    generating_stub_(false),
+    allow_stub_calls_(true),
+    code_object_(Heap::undefined_value()) {
+}
+
+
+void MacroAssembler::LoadRoot(Register destination,
+                              Heap::RootListIndex index) {
+  movq(destination, Operand(r13, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::PushRoot(Heap::RootListIndex index) {
+  push(Operand(r13, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::CompareRoot(Register with,
+                                 Heap::RootListIndex index) {
+  cmpq(with, Operand(r13, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::CompareRoot(Operand with,
+                                 Heap::RootListIndex index) {
+  LoadRoot(kScratchRegister, index);
+  cmpq(with, kScratchRegister);
+}
+
+
+static void RecordWriteHelper(MacroAssembler* masm,
+                              Register object,
+                              Register addr,
+                              Register scratch) {
+  Label fast;
+
+  // Compute the page start address from the heap object pointer, and reuse
+  // the 'object' register for it.
+  ASSERT(is_int32(~Page::kPageAlignmentMask));
+  masm->and_(object,
+             Immediate(static_cast<int32_t>(~Page::kPageAlignmentMask)));
+  Register page_start = object;
+
+  // Compute the bit addr in the remembered set/index of the pointer in the
+  // page. Reuse 'addr' as pointer_offset.
+  masm->subq(addr, page_start);
+  masm->shr(addr, Immediate(kPointerSizeLog2));
+  Register pointer_offset = addr;
+
+  // If the bit offset lies beyond the normal remembered set range, it is in
+  // the extra remembered set area of a large object.
+  masm->cmpq(pointer_offset, Immediate(Page::kPageSize / kPointerSize));
+  masm->j(less, &fast);
+
+  // Adjust 'page_start' so that addressing using 'pointer_offset' hits the
+  // extra remembered set after the large object.
+
+  // Load the array length into 'scratch'.
+  masm->movl(scratch,
+             Operand(page_start,
+                     Page::kObjectStartOffset + FixedArray::kLengthOffset));
+  Register array_length = scratch;
+
+  // Extra remembered set starts right after the large object (a FixedArray), at
+  //   page_start + kObjectStartOffset + objectSize
+  // where objectSize is FixedArray::kHeaderSize + kPointerSize * array_length.
+  // Add the delta between the end of the normal RSet and the start of the
+  // extra RSet to 'page_start', so that addressing the bit using
+  // 'pointer_offset' hits the extra RSet words.
+  masm->lea(page_start,
+            Operand(page_start, array_length, times_pointer_size,
+                    Page::kObjectStartOffset + FixedArray::kHeaderSize
+                        - Page::kRSetEndOffset));
+
+  // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
+  // to limit code size. We should probably evaluate this decision by
+  // measuring the performance of an equivalent implementation using
+  // "simpler" instructions
+  masm->bind(&fast);
+  masm->bts(Operand(page_start, Page::kRSetOffset), pointer_offset);
+}
+
+
+class RecordWriteStub : public CodeStub {
+ public:
+  RecordWriteStub(Register object, Register addr, Register scratch)
+      : object_(object), addr_(addr), scratch_(scratch) { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  Register object_;
+  Register addr_;
+  Register scratch_;
+
+#ifdef DEBUG
+  void Print() {
+    PrintF("RecordWriteStub (object reg %d), (addr reg %d), (scratch reg %d)\n",
+           object_.code(), addr_.code(), scratch_.code());
+  }
+#endif
+
+  // Minor key encoding in 12 bits of three registers (object, address and
+  // scratch) OOOOAAAASSSS.
+  class ScratchBits: public BitField<uint32_t, 0, 4> {};
+  class AddressBits: public BitField<uint32_t, 4, 4> {};
+  class ObjectBits: public BitField<uint32_t, 8, 4> {};
+
+  Major MajorKey() { return RecordWrite; }
+
+  int MinorKey() {
+    // Encode the registers.
+    return ObjectBits::encode(object_.code()) |
+           AddressBits::encode(addr_.code()) |
+           ScratchBits::encode(scratch_.code());
+  }
+};
+
+
+void RecordWriteStub::Generate(MacroAssembler* masm) {
+  RecordWriteHelper(masm, object_, addr_, scratch_);
+  masm->ret(0);
+}
+
+
+// Set the remembered set bit for [object+offset].
+// object is the object being stored into, value is the object being stored.
+// If offset is zero, then the scratch register contains the array index into
+// the elements array represented as a Smi.
+// All registers are clobbered by the operation.
+void MacroAssembler::RecordWrite(Register object,
+                                 int offset,
+                                 Register value,
+                                 Register scratch) {
+  // First, check if a remembered set write is even needed. The tests below
+  // catch stores of Smis and stores into young gen (which does not have space
+  // for the remembered set bits.
+  Label done;
+
+  // Test that the object address is not in the new space.  We cannot
+  // set remembered set bits in the new space.
+  movq(value, object);
+  ASSERT(is_int32(static_cast<int64_t>(Heap::NewSpaceMask())));
+  and_(value, Immediate(static_cast<int32_t>(Heap::NewSpaceMask())));
+  movq(kScratchRegister, ExternalReference::new_space_start());
+  cmpq(value, kScratchRegister);
+  j(equal, &done);
+
+  if ((offset > 0) && (offset < Page::kMaxHeapObjectSize)) {
+    // Compute the bit offset in the remembered set, leave it in 'value'.
+    lea(value, Operand(object, offset));
+    ASSERT(is_int32(Page::kPageAlignmentMask));
+    and_(value, Immediate(static_cast<int32_t>(Page::kPageAlignmentMask)));
+    shr(value, Immediate(kObjectAlignmentBits));
+
+    // Compute the page address from the heap object pointer, leave it in
+    // 'object' (immediate value is sign extended).
+    and_(object, Immediate(~Page::kPageAlignmentMask));
+
+    // NOTE: For now, we use the bit-test-and-set (bts) x86 instruction
+    // to limit code size. We should probably evaluate this decision by
+    // measuring the performance of an equivalent implementation using
+    // "simpler" instructions
+    bts(Operand(object, Page::kRSetOffset), value);
+  } else {
+    Register dst = scratch;
+    if (offset != 0) {
+      lea(dst, Operand(object, offset));
+    } else {
+      // array access: calculate the destination address in the same manner as
+      // KeyedStoreIC::GenerateGeneric.  Multiply a smi by 4 to get an offset
+      // into an array of pointers.
+      lea(dst, Operand(object, dst, times_half_pointer_size,
+                       FixedArray::kHeaderSize - kHeapObjectTag));
+    }
+    // If we are already generating a shared stub, not inlining the
+    // record write code isn't going to save us any memory.
+    if (generating_stub()) {
+      RecordWriteHelper(this, object, dst, value);
+    } else {
+      RecordWriteStub stub(object, dst, value);
+      CallStub(&stub);
+    }
+  }
+
+  bind(&done);
+}
+
+
+void MacroAssembler::Assert(Condition cc, const char* msg) {
+  if (FLAG_debug_code) Check(cc, msg);
+}
+
+
+void MacroAssembler::Check(Condition cc, const char* msg) {
+  Label L;
+  j(cc, &L);
+  Abort(msg);
+  // will not return here
+  bind(&L);
+}
+
+
+void MacroAssembler::NegativeZeroTest(Register result,
+                                      Register op,
+                                      Label* then_label) {
+  Label ok;
+  testl(result, result);
+  j(not_zero, &ok);
+  testl(op, op);
+  j(sign, then_label);
+  bind(&ok);
+}
+
+
+void MacroAssembler::Abort(const char* msg) {
+  // We want to pass the msg string like a smi to avoid GC
+  // problems, however msg is not guaranteed to be aligned
+  // properly. Instead, we pass an aligned pointer that is
+  // a proper v8 smi, but also pass the alignment difference
+  // from the real pointer as a smi.
+  intptr_t p1 = reinterpret_cast<intptr_t>(msg);
+  intptr_t p0 = (p1 & ~kSmiTagMask) + kSmiTag;
+  // Note: p0 might not be a valid Smi *value*, but it has a valid Smi tag.
+  ASSERT(reinterpret_cast<Object*>(p0)->IsSmi());
+#ifdef DEBUG
+  if (msg != NULL) {
+    RecordComment("Abort message: ");
+    RecordComment(msg);
+  }
+#endif
+  push(rax);
+  movq(kScratchRegister, p0, RelocInfo::NONE);
+  push(kScratchRegister);
+  movq(kScratchRegister,
+       reinterpret_cast<intptr_t>(Smi::FromInt(p1 - p0)),
+       RelocInfo::NONE);
+  push(kScratchRegister);
+  CallRuntime(Runtime::kAbort, 2);
+  // will not return here
+}
+
+
+void MacroAssembler::CallStub(CodeStub* stub) {
+  ASSERT(allow_stub_calls());  // calls are not allowed in some stubs
+  Call(stub->GetCode(), RelocInfo::CODE_TARGET);
+}
+
+
+void MacroAssembler::StubReturn(int argc) {
+  ASSERT(argc >= 1 && generating_stub());
+  ret((argc - 1) * kPointerSize);
+}
+
+
+void MacroAssembler::IllegalOperation(int num_arguments) {
+  if (num_arguments > 0) {
+    addq(rsp, Immediate(num_arguments * kPointerSize));
+  }
+  LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::FunctionId id, int num_arguments) {
+  CallRuntime(Runtime::FunctionForId(id), num_arguments);
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) {
+  // If the expected number of arguments of the runtime function is
+  // constant, we check that the actual number of arguments match the
+  // expectation.
+  if (f->nargs >= 0 && f->nargs != num_arguments) {
+    IllegalOperation(num_arguments);
+    return;
+  }
+
+  Runtime::FunctionId function_id =
+      static_cast<Runtime::FunctionId>(f->stub_id);
+  RuntimeStub stub(function_id, num_arguments);
+  CallStub(&stub);
+}
+
+
+void MacroAssembler::TailCallRuntime(ExternalReference const& ext,
+                                     int num_arguments,
+                                     int result_size) {
+  // ----------- S t a t e -------------
+  //  -- rsp[0] : return address
+  //  -- rsp[8] : argument num_arguments - 1
+  //  ...
+  //  -- rsp[8 * num_arguments] : argument 0 (receiver)
+  // -----------------------------------
+
+  // TODO(1236192): Most runtime routines don't need the number of
+  // arguments passed in because it is constant. At some point we
+  // should remove this need and make the runtime routine entry code
+  // smarter.
+  movq(rax, Immediate(num_arguments));
+  JumpToRuntime(ext, result_size);
+}
+
+
+void MacroAssembler::JumpToRuntime(const ExternalReference& ext,
+                                   int result_size) {
+  // Set the entry point and jump to the C entry runtime stub.
+  movq(rbx, ext);
+  CEntryStub ces(result_size);
+  movq(kScratchRegister, ces.GetCode(), RelocInfo::CODE_TARGET);
+  jmp(kScratchRegister);
+}
+
+
+void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
+  bool resolved;
+  Handle<Code> code = ResolveBuiltin(id, &resolved);
+
+  const char* name = Builtins::GetName(id);
+  int argc = Builtins::GetArgumentsCount(id);
+
+  movq(target, code, RelocInfo::EMBEDDED_OBJECT);
+  if (!resolved) {
+    uint32_t flags =
+        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
+        Bootstrapper::FixupFlagsIsPCRelative::encode(false) |
+        Bootstrapper::FixupFlagsUseCodeObject::encode(true);
+    Unresolved entry = { pc_offset() - sizeof(intptr_t), flags, name };
+    unresolved_.Add(entry);
+  }
+  addq(target, Immediate(Code::kHeaderSize - kHeapObjectTag));
+}
+
+
+Handle<Code> MacroAssembler::ResolveBuiltin(Builtins::JavaScript id,
+                                            bool* resolved) {
+  // Move the builtin function into the temporary function slot by
+  // reading it from the builtins object. NOTE: We should be able to
+  // reduce this to two instructions by putting the function table in
+  // the global object instead of the "builtins" object and by using a
+  // real register for the function.
+  movq(rdx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+  movq(rdx, FieldOperand(rdx, GlobalObject::kBuiltinsOffset));
+  int builtins_offset =
+      JSBuiltinsObject::kJSBuiltinsOffset + (id * kPointerSize);
+  movq(rdi, FieldOperand(rdx, builtins_offset));
+
+
+  return Builtins::GetCode(id, resolved);
+}
+
+
+void MacroAssembler::Set(Register dst, int64_t x) {
+  if (x == 0) {
+    xor_(dst, dst);
+  } else if (is_int32(x)) {
+    movq(dst, Immediate(x));
+  } else if (is_uint32(x)) {
+    movl(dst, Immediate(x));
+  } else {
+    movq(dst, x, RelocInfo::NONE);
+  }
+}
+
+
+void MacroAssembler::Set(const Operand& dst, int64_t x) {
+  if (x == 0) {
+    xor_(kScratchRegister, kScratchRegister);
+    movq(dst, kScratchRegister);
+  } else if (is_int32(x)) {
+    movq(dst, Immediate(x));
+  } else if (is_uint32(x)) {
+    movl(dst, Immediate(x));
+  } else {
+    movq(kScratchRegister, x, RelocInfo::NONE);
+    movq(dst, kScratchRegister);
+  }
+}
+
+
+// ----------------------------------------------------------------------------
+// Smi tagging, untagging and tag detection.
+
+
+void MacroAssembler::Integer32ToSmi(Register dst, Register src) {
+  ASSERT_EQ(1, kSmiTagSize);
+  ASSERT_EQ(0, kSmiTag);
+#ifdef DEBUG
+    cmpq(src, Immediate(0xC0000000u));
+    Check(positive, "Smi conversion overflow");
+#endif
+  if (dst.is(src)) {
+    addl(dst, src);
+  } else {
+    lea(dst, Operand(src, src, times_1, 0));
+  }
+}
+
+
+void MacroAssembler::Integer32ToSmi(Register dst,
+                                    Register src,
+                                    Label* on_overflow) {
+  ASSERT_EQ(1, kSmiTagSize);
+  ASSERT_EQ(0, kSmiTag);
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  addl(dst, src);
+  j(overflow, on_overflow);
+}
+
+
+void MacroAssembler::Integer64AddToSmi(Register dst,
+                                       Register src,
+                                       int constant) {
+#ifdef DEBUG
+  movl(kScratchRegister, src);
+  addl(kScratchRegister, Immediate(constant));
+  Check(no_overflow, "Add-and-smi-convert overflow");
+  Condition valid = CheckInteger32ValidSmiValue(kScratchRegister);
+  Check(valid, "Add-and-smi-convert overflow");
+#endif
+  lea(dst, Operand(src, src, times_1, constant << kSmiTagSize));
+}
+
+
+void MacroAssembler::SmiToInteger32(Register dst, Register src) {
+  ASSERT_EQ(1, kSmiTagSize);
+  ASSERT_EQ(0, kSmiTag);
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  sarl(dst, Immediate(kSmiTagSize));
+}
+
+
+void MacroAssembler::SmiToInteger64(Register dst, Register src) {
+  ASSERT_EQ(1, kSmiTagSize);
+  ASSERT_EQ(0, kSmiTag);
+  movsxlq(dst, src);
+  sar(dst, Immediate(kSmiTagSize));
+}
+
+
+void MacroAssembler::PositiveSmiTimesPowerOfTwoToInteger64(Register dst,
+                                                           Register src,
+                                                           int power) {
+  ASSERT(power >= 0);
+  ASSERT(power < 64);
+  if (power == 0) {
+    SmiToInteger64(dst, src);
+    return;
+  }
+  movsxlq(dst, src);
+  shl(dst, Immediate(power - 1));
+}
+
+void MacroAssembler::JumpIfSmi(Register src, Label* on_smi) {
+  ASSERT_EQ(0, kSmiTag);
+  testl(src, Immediate(kSmiTagMask));
+  j(zero, on_smi);
+}
+
+
+void MacroAssembler::JumpIfNotSmi(Register src, Label* on_not_smi) {
+  Condition not_smi = CheckNotSmi(src);
+  j(not_smi, on_not_smi);
+}
+
+
+void MacroAssembler::JumpIfNotPositiveSmi(Register src,
+                                          Label* on_not_positive_smi) {
+  Condition not_positive_smi = CheckNotPositiveSmi(src);
+  j(not_positive_smi, on_not_positive_smi);
+}
+
+
+void MacroAssembler::JumpIfSmiEqualsConstant(Register src,
+                                             int constant,
+                                             Label* on_equals) {
+  if (Smi::IsValid(constant)) {
+    Condition are_equal = CheckSmiEqualsConstant(src, constant);
+    j(are_equal, on_equals);
+  }
+}
+
+
+void MacroAssembler::JumpIfSmiGreaterEqualsConstant(Register src,
+                                                    int constant,
+                                                    Label* on_greater_equals) {
+  if (Smi::IsValid(constant)) {
+    Condition are_greater_equal = CheckSmiGreaterEqualsConstant(src, constant);
+    j(are_greater_equal, on_greater_equals);
+  } else if (constant < Smi::kMinValue) {
+    jmp(on_greater_equals);
+  }
+}
+
+
+void MacroAssembler::JumpIfNotValidSmiValue(Register src, Label* on_invalid) {
+  Condition is_valid = CheckInteger32ValidSmiValue(src);
+  j(ReverseCondition(is_valid), on_invalid);
+}
+
+
+
+void MacroAssembler::JumpIfNotBothSmi(Register src1,
+                                      Register src2,
+                                      Label* on_not_both_smi) {
+  Condition not_both_smi = CheckNotBothSmi(src1, src2);
+  j(not_both_smi, on_not_both_smi);
+}
+
+Condition MacroAssembler::CheckSmi(Register src) {
+  testb(src, Immediate(kSmiTagMask));
+  return zero;
+}
+
+
+Condition MacroAssembler::CheckNotSmi(Register src) {
+  ASSERT_EQ(0, kSmiTag);
+  testb(src, Immediate(kSmiTagMask));
+  return not_zero;
+}
+
+
+Condition MacroAssembler::CheckPositiveSmi(Register src) {
+  ASSERT_EQ(0, kSmiTag);
+  testl(src, Immediate(static_cast<uint32_t>(0x80000000u | kSmiTagMask)));
+  return zero;
+}
+
+
+Condition MacroAssembler::CheckNotPositiveSmi(Register src) {
+  ASSERT_EQ(0, kSmiTag);
+  testl(src, Immediate(static_cast<uint32_t>(0x80000000u | kSmiTagMask)));
+  return not_zero;
+}
+
+
+Condition MacroAssembler::CheckBothSmi(Register first, Register second) {
+  if (first.is(second)) {
+    return CheckSmi(first);
+  }
+  movl(kScratchRegister, first);
+  orl(kScratchRegister, second);
+  return CheckSmi(kScratchRegister);
+}
+
+
+Condition MacroAssembler::CheckNotBothSmi(Register first, Register second) {
+  ASSERT_EQ(0, kSmiTag);
+  if (first.is(second)) {
+    return CheckNotSmi(first);
+  }
+  movl(kScratchRegister, first);
+  or_(kScratchRegister, second);
+  return CheckNotSmi(kScratchRegister);
+}
+
+
+Condition MacroAssembler::CheckIsMinSmi(Register src) {
+  ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
+  cmpl(src, Immediate(0x40000000));
+  return equal;
+}
+
+Condition MacroAssembler::CheckSmiEqualsConstant(Register src, int constant) {
+  if (constant == 0) {
+    testl(src, src);
+    return zero;
+  }
+  if (Smi::IsValid(constant)) {
+    cmpl(src, Immediate(Smi::FromInt(constant)));
+    return zero;
+  }
+  // Can't be equal.
+  UNREACHABLE();
+  return no_condition;
+}
+
+
+Condition MacroAssembler::CheckSmiGreaterEqualsConstant(Register src,
+                                                        int constant) {
+  if (constant == 0) {
+    testl(src, Immediate(static_cast<uint32_t>(0x80000000u)));
+    return positive;
+  }
+  if (Smi::IsValid(constant)) {
+    cmpl(src, Immediate(Smi::FromInt(constant)));
+    return greater_equal;
+  }
+  // Can't be equal.
+  UNREACHABLE();
+  return no_condition;
+}
+
+
+Condition MacroAssembler::CheckInteger32ValidSmiValue(Register src) {
+  // A 32-bit integer value can be converted to a smi if it is in the
+  // range [-2^30 .. 2^30-1]. That is equivalent to having its 32-bit
+  // representation have bits 30 and 31 be equal.
+  cmpl(src, Immediate(0xC0000000u));
+  return positive;
+}
+
+
+void MacroAssembler::SmiNeg(Register dst,
+                            Register src,
+                            Label* on_not_smi_result) {
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  negl(dst);
+  testl(dst, Immediate(0x7fffffff));
+  // If the result is zero or 0x80000000, negation failed to create a smi.
+  j(equal, on_not_smi_result);
+}
+
+
+void MacroAssembler::SmiAdd(Register dst,
+                            Register src1,
+                            Register src2,
+                            Label* on_not_smi_result) {
+  ASSERT(!dst.is(src2));
+  if (!dst.is(src1)) {
+    movl(dst, src1);
+  }
+  addl(dst, src2);
+  if (!dst.is(src1)) {
+    j(overflow, on_not_smi_result);
+  } else {
+    Label smi_result;
+    j(no_overflow, &smi_result);
+    // Restore src1.
+    subl(src1, src2);
+    jmp(on_not_smi_result);
+    bind(&smi_result);
+  }
+}
+
+
+
+void MacroAssembler::SmiSub(Register dst,
+                            Register src1,
+                            Register src2,
+                            Label* on_not_smi_result) {
+  ASSERT(!dst.is(src2));
+  if (!dst.is(src1)) {
+    movl(dst, src1);
+  }
+  subl(dst, src2);
+  if (!dst.is(src1)) {
+    j(overflow, on_not_smi_result);
+  } else {
+    Label smi_result;
+    j(no_overflow, &smi_result);
+    // Restore src1.
+    addl(src1, src2);
+    jmp(on_not_smi_result);
+    bind(&smi_result);
+  }
+}
+
+
+void MacroAssembler::SmiMul(Register dst,
+                            Register src1,
+                            Register src2,
+                            Label* on_not_smi_result) {
+  ASSERT(!dst.is(src2));
+
+  if (dst.is(src1)) {
+    movq(kScratchRegister, src1);
+  }
+  SmiToInteger32(dst, src1);
+
+  imull(dst, src2);
+  j(overflow, on_not_smi_result);
+
+  // Check for negative zero result.  If product is zero, and one
+  // argument is negative, go to slow case.  The frame is unchanged
+  // in this block, so local control flow can use a Label rather
+  // than a JumpTarget.
+  Label non_zero_result;
+  testl(dst, dst);
+  j(not_zero, &non_zero_result);
+
+  // Test whether either operand is negative (the other must be zero).
+  orl(kScratchRegister, src2);
+  j(negative, on_not_smi_result);
+  bind(&non_zero_result);
+}
+
+
+void MacroAssembler::SmiTryAddConstant(Register dst,
+                                       Register src,
+                                       int32_t constant,
+                                       Label* on_not_smi_result) {
+  // Does not assume that src is a smi.
+  ASSERT_EQ(1, kSmiTagMask);
+  ASSERT_EQ(0, kSmiTag);
+  ASSERT(Smi::IsValid(constant));
+
+  Register tmp = (src.is(dst) ? kScratchRegister : dst);
+  movl(tmp, src);
+  addl(tmp, Immediate(Smi::FromInt(constant)));
+  if (tmp.is(kScratchRegister)) {
+    j(overflow, on_not_smi_result);
+    testl(tmp, Immediate(kSmiTagMask));
+    j(not_zero, on_not_smi_result);
+    movl(dst, tmp);
+  } else {
+    movl(kScratchRegister, Immediate(kSmiTagMask));
+    cmovl(overflow, dst, kScratchRegister);
+    testl(dst, kScratchRegister);
+    j(not_zero, on_not_smi_result);
+  }
+}
+
+
+void MacroAssembler::SmiAddConstant(Register dst,
+                                    Register src,
+                                    int32_t constant,
+                                    Label* on_not_smi_result) {
+  ASSERT(Smi::IsValid(constant));
+  if (on_not_smi_result == NULL) {
+    if (dst.is(src)) {
+      movl(dst, src);
+    } else {
+      lea(dst, Operand(src, constant << kSmiTagSize));
+    }
+  } else {
+    if (!dst.is(src)) {
+      movl(dst, src);
+    }
+    addl(dst, Immediate(Smi::FromInt(constant)));
+    if (!dst.is(src)) {
+      j(overflow, on_not_smi_result);
+    } else {
+      Label result_ok;
+      j(no_overflow, &result_ok);
+      subl(dst, Immediate(Smi::FromInt(constant)));
+      jmp(on_not_smi_result);
+      bind(&result_ok);
+    }
+  }
+}
+
+
+void MacroAssembler::SmiSubConstant(Register dst,
+                                    Register src,
+                                    int32_t constant,
+                                    Label* on_not_smi_result) {
+  ASSERT(Smi::IsValid(constant));
+  Smi* smi_value = Smi::FromInt(constant);
+  if (dst.is(src)) {
+    // Optimistic subtract - may change value of dst register,
+    // if it has garbage bits in the higher half, but will not change
+    // the value as a tagged smi.
+    subl(dst, Immediate(smi_value));
+    if (on_not_smi_result != NULL) {
+      Label add_success;
+      j(no_overflow, &add_success);
+      addl(dst, Immediate(smi_value));
+      jmp(on_not_smi_result);
+      bind(&add_success);
+    }
+  } else {
+    UNIMPLEMENTED();  // Not used yet.
+  }
+}
+
+
+void MacroAssembler::SmiDiv(Register dst,
+                            Register src1,
+                            Register src2,
+                            Label* on_not_smi_result) {
+  ASSERT(!src2.is(rax));
+  ASSERT(!src2.is(rdx));
+  ASSERT(!src1.is(rdx));
+
+  // Check for 0 divisor (result is +/-Infinity).
+  Label positive_divisor;
+  testl(src2, src2);
+  j(zero, on_not_smi_result);
+  j(positive, &positive_divisor);
+  // Check for negative zero result.  If the dividend is zero, and the
+  // divisor is negative, return a floating point negative zero.
+  testl(src1, src1);
+  j(zero, on_not_smi_result);
+  bind(&positive_divisor);
+
+  // Sign extend src1 into edx:eax.
+  if (!src1.is(rax)) {
+    movl(rax, src1);
+  }
+  cdq();
+
+  idivl(src2);
+  // Check for the corner case of dividing the most negative smi by
+  // -1. We cannot use the overflow flag, since it is not set by
+  // idiv instruction.
+  ASSERT(kSmiTag == 0 && kSmiTagSize == 1);
+  cmpl(rax, Immediate(0x40000000));
+  j(equal, on_not_smi_result);
+  // Check that the remainder is zero.
+  testl(rdx, rdx);
+  j(not_zero, on_not_smi_result);
+  // Tag the result and store it in the destination register.
+  Integer32ToSmi(dst, rax);
+}
+
+
+void MacroAssembler::SmiMod(Register dst,
+                            Register src1,
+                            Register src2,
+                            Label* on_not_smi_result) {
+  ASSERT(!dst.is(kScratchRegister));
+  ASSERT(!src1.is(kScratchRegister));
+  ASSERT(!src2.is(kScratchRegister));
+  ASSERT(!src2.is(rax));
+  ASSERT(!src2.is(rdx));
+  ASSERT(!src1.is(rdx));
+
+  testl(src2, src2);
+  j(zero, on_not_smi_result);
+
+  if (src1.is(rax)) {
+    // Mist remember the value to see if a zero result should
+    // be a negative zero.
+    movl(kScratchRegister, rax);
+  } else {
+    movl(rax, src1);
+  }
+  // Sign extend eax into edx:eax.
+  cdq();
+  idivl(src2);
+  // Check for a negative zero result.  If the result is zero, and the
+  // dividend is negative, return a floating point negative zero.
+  Label non_zero_result;
+  testl(rdx, rdx);
+  j(not_zero, &non_zero_result);
+  if (src1.is(rax)) {
+    testl(kScratchRegister, kScratchRegister);
+  } else {
+    testl(src1, src1);
+  }
+  j(negative, on_not_smi_result);
+  bind(&non_zero_result);
+  if (!dst.is(rdx)) {
+    movl(dst, rdx);
+  }
+}
+
+
+void MacroAssembler::SmiNot(Register dst, Register src) {
+  if (dst.is(src)) {
+    not_(dst);
+    // Remove inverted smi-tag.  The mask is sign-extended to 64 bits.
+    xor_(src, Immediate(kSmiTagMask));
+  } else {
+    ASSERT_EQ(0, kSmiTag);
+    lea(dst, Operand(src, kSmiTagMask));
+    not_(dst);
+  }
+}
+
+
+void MacroAssembler::SmiAnd(Register dst, Register src1, Register src2) {
+  if (!dst.is(src1)) {
+    movl(dst, src1);
+  }
+  and_(dst, src2);
+}
+
+
+void MacroAssembler::SmiAndConstant(Register dst, Register src, int constant) {
+  ASSERT(Smi::IsValid(constant));
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  and_(dst, Immediate(Smi::FromInt(constant)));
+}
+
+
+void MacroAssembler::SmiOr(Register dst, Register src1, Register src2) {
+  if (!dst.is(src1)) {
+    movl(dst, src1);
+  }
+  or_(dst, src2);
+}
+
+
+void MacroAssembler::SmiOrConstant(Register dst, Register src, int constant) {
+  ASSERT(Smi::IsValid(constant));
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  or_(dst, Immediate(Smi::FromInt(constant)));
+}
+
+void MacroAssembler::SmiXor(Register dst, Register src1, Register src2) {
+  if (!dst.is(src1)) {
+    movl(dst, src1);
+  }
+  xor_(dst, src2);
+}
+
+
+void MacroAssembler::SmiXorConstant(Register dst, Register src, int constant) {
+  ASSERT(Smi::IsValid(constant));
+  if (!dst.is(src)) {
+    movl(dst, src);
+  }
+  xor_(dst, Immediate(Smi::FromInt(constant)));
+}
+
+
+
+void MacroAssembler::SmiShiftArithmeticRightConstant(Register dst,
+                                                     Register src,
+                                                     int shift_value) {
+  if (shift_value > 0) {
+    if (dst.is(src)) {
+      sarl(dst, Immediate(shift_value));
+      and_(dst, Immediate(~kSmiTagMask));
+    } else {
+      UNIMPLEMENTED();  // Not used.
+    }
+  }
+}
+
+
+void MacroAssembler::SmiShiftLogicalRightConstant(Register dst,
+                                                  Register src,
+                                                  int shift_value,
+                                                  Label* on_not_smi_result) {
+  // Logic right shift interprets its result as an *unsigned* number.
+  if (dst.is(src)) {
+    UNIMPLEMENTED();  // Not used.
+  } else {
+    movl(dst, src);
+    // Untag the smi.
+    sarl(dst, Immediate(kSmiTagSize));
+    if (shift_value < 2) {
+      // A negative Smi shifted right two is in the positive Smi range,
+      // but if shifted only by zero or one, it never is.
+      j(negative, on_not_smi_result);
+    }
+    if (shift_value > 0) {
+      // Do the right shift on the integer value.
+      shrl(dst, Immediate(shift_value));
+    }
+    // Re-tag the result.
+    addl(dst, dst);
+  }
+}
+
+
+void MacroAssembler::SmiShiftLeftConstant(Register dst,
+                                          Register src,
+                                          int shift_value,
+                                          Label* on_not_smi_result) {
+  if (dst.is(src)) {
+    UNIMPLEMENTED();  // Not used.
+  } else {
+    movl(dst, src);
+    if (shift_value > 0) {
+      // Treat dst as an untagged integer value equal to two times the
+      // smi value of src, i.e., already shifted left by one.
+      if (shift_value > 1) {
+        shll(dst, Immediate(shift_value - 1));
+      }
+      // Convert int result to Smi, checking that it is in smi range.
+      ASSERT(kSmiTagSize == 1);  // adjust code if not the case
+      Integer32ToSmi(dst, dst, on_not_smi_result);
+    }
+  }
+}
+
+
+void MacroAssembler::SmiShiftLeft(Register dst,
+                                  Register src1,
+                                  Register src2,
+                                  Label* on_not_smi_result) {
+  ASSERT(!dst.is(rcx));
+  Label result_ok;
+  // Untag both operands.
+  SmiToInteger32(dst, src1);
+  SmiToInteger32(rcx, src2);
+  shll(dst);
+  // Check that the *signed* result fits in a smi.
+  Condition is_valid = CheckInteger32ValidSmiValue(dst);
+  j(is_valid, &result_ok);
+  // Restore the relevant bits of the source registers
+  // and call the slow version.
+  if (dst.is(src1)) {
+    shrl(dst);
+    Integer32ToSmi(dst, dst);
+  }
+  Integer32ToSmi(rcx, rcx);
+  jmp(on_not_smi_result);
+  bind(&result_ok);
+  Integer32ToSmi(dst, dst);
+}
+
+
+void MacroAssembler::SmiShiftLogicalRight(Register dst,
+                                          Register src1,
+                                          Register src2,
+                                          Label* on_not_smi_result) {
+  ASSERT(!dst.is(rcx));
+  Label result_ok;
+  // Untag both operands.
+  SmiToInteger32(dst, src1);
+  SmiToInteger32(rcx, src2);
+
+  shrl(dst);
+  // Check that the *unsigned* result fits in a smi.
+  // I.e., that it is a valid positive smi value. The positive smi
+  // values are  0..0x3fffffff, i.e., neither of the top-most two
+  // bits can be set.
+  //
+  // These two cases can only happen with shifts by 0 or 1 when
+  // handed a valid smi.  If the answer cannot be represented by a
+  // smi, restore the left and right arguments, and jump to slow
+  // case.  The low bit of the left argument may be lost, but only
+  // in a case where it is dropped anyway.
+  testl(dst, Immediate(0xc0000000));
+  j(zero, &result_ok);
+  if (dst.is(src1)) {
+    shll(dst);
+    Integer32ToSmi(dst, dst);
+  }
+  Integer32ToSmi(rcx, rcx);
+  jmp(on_not_smi_result);
+  bind(&result_ok);
+  // Smi-tag the result in answer.
+  Integer32ToSmi(dst, dst);
+}
+
+
+void MacroAssembler::SmiShiftArithmeticRight(Register dst,
+                                             Register src1,
+                                             Register src2) {
+  ASSERT(!dst.is(rcx));
+  // Untag both operands.
+  SmiToInteger32(dst, src1);
+  SmiToInteger32(rcx, src2);
+  // Shift as integer.
+  sarl(dst);
+  // Retag result.
+  Integer32ToSmi(dst, dst);
+}
+
+
+void MacroAssembler::SelectNonSmi(Register dst,
+                                  Register src1,
+                                  Register src2,
+                                  Label* on_not_smis) {
+  ASSERT(!dst.is(src1));
+  ASSERT(!dst.is(src2));
+  // Both operands must not be smis.
+#ifdef DEBUG
+  Condition not_both_smis = CheckNotBothSmi(src1, src2);
+  Check(not_both_smis, "Both registers were smis.");
+#endif
+  ASSERT_EQ(0, kSmiTag);
+  ASSERT_EQ(0, Smi::FromInt(0));
+  movq(kScratchRegister, Immediate(kSmiTagMask));
+  and_(kScratchRegister, src1);
+  testl(kScratchRegister, src2);
+  j(not_zero, on_not_smis);
+  // One operand is a smi.
+
+  ASSERT_EQ(1, static_cast<int>(kSmiTagMask));
+  // kScratchRegister still holds src1 & kSmiTag, which is either zero or one.
+  subq(kScratchRegister, Immediate(1));
+  // If src1 is a smi, then scratch register all 1s, else it is all 0s.
+  movq(dst, src1);
+  xor_(dst, src2);
+  and_(dst, kScratchRegister);
+  // If src1 is a smi, dst holds src1 ^ src2, else it is zero.
+  xor_(dst, src1);
+  // If src1 is a smi, dst is src2, else it is src1, i.e., a non-smi.
+}
+
+
+SmiIndex MacroAssembler::SmiToIndex(Register dst, Register src, int shift) {
+  ASSERT(is_uint6(shift));
+  if (shift == 0) {  // times_1.
+    SmiToInteger32(dst, src);
+    return SmiIndex(dst, times_1);
+  }
+  if (shift <= 4) {  // 2 - 16 times multiplier is handled using ScaleFactor.
+    // We expect that all smis are actually zero-padded. If this holds after
+    // checking, this line can be omitted.
+    movl(dst, src);  // Ensure that the smi is zero-padded.
+    return SmiIndex(dst, static_cast<ScaleFactor>(shift - kSmiTagSize));
+  }
+  // Shift by shift-kSmiTagSize.
+  movl(dst, src);  // Ensure that the smi is zero-padded.
+  shl(dst, Immediate(shift - kSmiTagSize));
+  return SmiIndex(dst, times_1);
+}
+
+
+SmiIndex MacroAssembler::SmiToNegativeIndex(Register dst,
+                                            Register src,
+                                            int shift) {
+  // Register src holds a positive smi.
+  ASSERT(is_uint6(shift));
+  if (shift == 0) {  // times_1.
+    SmiToInteger32(dst, src);
+    neg(dst);
+    return SmiIndex(dst, times_1);
+  }
+  if (shift <= 4) {  // 2 - 16 times multiplier is handled using ScaleFactor.
+    movl(dst, src);
+    neg(dst);
+    return SmiIndex(dst, static_cast<ScaleFactor>(shift - kSmiTagSize));
+  }
+  // Shift by shift-kSmiTagSize.
+  movl(dst, src);
+  neg(dst);
+  shl(dst, Immediate(shift - kSmiTagSize));
+  return SmiIndex(dst, times_1);
+}
+
+
+
+bool MacroAssembler::IsUnsafeSmi(Smi* value) {
+  return false;
+}
+
+void MacroAssembler::LoadUnsafeSmi(Register dst, Smi* source) {
+  UNIMPLEMENTED();
+}
+
+
+void MacroAssembler::Move(Register dst, Handle<Object> source) {
+  ASSERT(!source->IsFailure());
+  if (source->IsSmi()) {
+    if (IsUnsafeSmi(source)) {
+      LoadUnsafeSmi(dst, source);
+    } else {
+      int32_t smi = static_cast<int32_t>(reinterpret_cast<intptr_t>(*source));
+      movq(dst, Immediate(smi));
+    }
+  } else {
+    movq(dst, source, RelocInfo::EMBEDDED_OBJECT);
+  }
+}
+
+
+void MacroAssembler::Move(const Operand& dst, Handle<Object> source) {
+  if (source->IsSmi()) {
+    int32_t smi = static_cast<int32_t>(reinterpret_cast<intptr_t>(*source));
+    movq(dst, Immediate(smi));
+  } else {
+    movq(kScratchRegister, source, RelocInfo::EMBEDDED_OBJECT);
+    movq(dst, kScratchRegister);
+  }
+}
+
+
+void MacroAssembler::Cmp(Register dst, Handle<Object> source) {
+  Move(kScratchRegister, source);
+  cmpq(dst, kScratchRegister);
+}
+
+
+void MacroAssembler::Cmp(const Operand& dst, Handle<Object> source) {
+  if (source->IsSmi()) {
+    if (IsUnsafeSmi(source)) {
+      LoadUnsafeSmi(kScratchRegister, source);
+      cmpl(dst, kScratchRegister);
+    } else {
+      // For smi-comparison, it suffices to compare the low 32 bits.
+      int32_t smi = static_cast<int32_t>(reinterpret_cast<intptr_t>(*source));
+      cmpl(dst, Immediate(smi));
+    }
+  } else {
+    ASSERT(source->IsHeapObject());
+    movq(kScratchRegister, source, RelocInfo::EMBEDDED_OBJECT);
+    cmpq(dst, kScratchRegister);
+  }
+}
+
+
+void MacroAssembler::Push(Handle<Object> source) {
+  if (source->IsSmi()) {
+    if (IsUnsafeSmi(source)) {
+      LoadUnsafeSmi(kScratchRegister, source);
+      push(kScratchRegister);
+    } else {
+      int32_t smi = static_cast<int32_t>(reinterpret_cast<intptr_t>(*source));
+      push(Immediate(smi));
+    }
+  } else {
+    ASSERT(source->IsHeapObject());
+    movq(kScratchRegister, source, RelocInfo::EMBEDDED_OBJECT);
+    push(kScratchRegister);
+  }
+}
+
+
+void MacroAssembler::Push(Smi* source) {
+  if (IsUnsafeSmi(source)) {
+    LoadUnsafeSmi(kScratchRegister, source);
+    push(kScratchRegister);
+  } else {
+    int32_t smi = static_cast<int32_t>(reinterpret_cast<intptr_t>(source));
+    push(Immediate(smi));
+  }
+}
+
+
+void MacroAssembler::Jump(ExternalReference ext) {
+  movq(kScratchRegister, ext);
+  jmp(kScratchRegister);
+}
+
+
+void MacroAssembler::Jump(Address destination, RelocInfo::Mode rmode) {
+  movq(kScratchRegister, destination, rmode);
+  jmp(kScratchRegister);
+}
+
+
+void MacroAssembler::Jump(Handle<Code> code_object, RelocInfo::Mode rmode) {
+  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  movq(kScratchRegister, code_object, rmode);
+#ifdef DEBUG
+  Label target;
+  bind(&target);
+#endif
+  jmp(kScratchRegister);
+#ifdef DEBUG
+  ASSERT_EQ(kCallTargetAddressOffset,
+            SizeOfCodeGeneratedSince(&target) + kPointerSize);
+#endif
+}
+
+
+void MacroAssembler::Call(ExternalReference ext) {
+  movq(kScratchRegister, ext);
+  call(kScratchRegister);
+}
+
+
+void MacroAssembler::Call(Address destination, RelocInfo::Mode rmode) {
+  movq(kScratchRegister, destination, rmode);
+  call(kScratchRegister);
+}
+
+
+void MacroAssembler::Call(Handle<Code> code_object, RelocInfo::Mode rmode) {
+  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  WriteRecordedPositions();
+  movq(kScratchRegister, code_object, rmode);
+#ifdef DEBUG
+  // Patch target is kPointer size bytes *before* target label.
+  Label target;
+  bind(&target);
+#endif
+  call(kScratchRegister);
+#ifdef DEBUG
+  ASSERT_EQ(kCallTargetAddressOffset,
+            SizeOfCodeGeneratedSince(&target) + kPointerSize);
+#endif
+}
+
+
+void MacroAssembler::PushTryHandler(CodeLocation try_location,
+                                    HandlerType type) {
+  // Adjust this code if not the case.
+  ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
+
+  // The pc (return address) is already on TOS.  This code pushes state,
+  // frame pointer and current handler.  Check that they are expected
+  // next on the stack, in that order.
+  ASSERT_EQ(StackHandlerConstants::kStateOffset,
+            StackHandlerConstants::kPCOffset - kPointerSize);
+  ASSERT_EQ(StackHandlerConstants::kFPOffset,
+            StackHandlerConstants::kStateOffset - kPointerSize);
+  ASSERT_EQ(StackHandlerConstants::kNextOffset,
+            StackHandlerConstants::kFPOffset - kPointerSize);
+
+  if (try_location == IN_JAVASCRIPT) {
+    if (type == TRY_CATCH_HANDLER) {
+      push(Immediate(StackHandler::TRY_CATCH));
+    } else {
+      push(Immediate(StackHandler::TRY_FINALLY));
+    }
+    push(rbp);
+  } else {
+    ASSERT(try_location == IN_JS_ENTRY);
+    // The frame pointer does not point to a JS frame so we save NULL
+    // for rbp. We expect the code throwing an exception to check rbp
+    // before dereferencing it to restore the context.
+    push(Immediate(StackHandler::ENTRY));
+    push(Immediate(0));  // NULL frame pointer.
+  }
+  // Save the current handler.
+  movq(kScratchRegister, ExternalReference(Top::k_handler_address));
+  push(Operand(kScratchRegister, 0));
+  // Link this handler.
+  movq(Operand(kScratchRegister, 0), rsp);
+}
+
+
+void MacroAssembler::Ret() {
+  ret(0);
+}
+
+
+void MacroAssembler::FCmp() {
+  fucompp();
+  push(rax);
+  fnstsw_ax();
+  if (CpuFeatures::IsSupported(CpuFeatures::SAHF)) {
+    sahf();
+  } else {
+    shrl(rax, Immediate(8));
+    and_(rax, Immediate(0xFF));
+    push(rax);
+    popfq();
+  }
+  pop(rax);
+}
+
+
+void MacroAssembler::CmpObjectType(Register heap_object,
+                                   InstanceType type,
+                                   Register map) {
+  movq(map, FieldOperand(heap_object, HeapObject::kMapOffset));
+  CmpInstanceType(map, type);
+}
+
+
+void MacroAssembler::CmpInstanceType(Register map, InstanceType type) {
+  cmpb(FieldOperand(map, Map::kInstanceTypeOffset),
+       Immediate(static_cast<int8_t>(type)));
+}
+
+
+void MacroAssembler::TryGetFunctionPrototype(Register function,
+                                             Register result,
+                                             Label* miss) {
+  // Check that the receiver isn't a smi.
+  testl(function, Immediate(kSmiTagMask));
+  j(zero, miss);
+
+  // Check that the function really is a function.
+  CmpObjectType(function, JS_FUNCTION_TYPE, result);
+  j(not_equal, miss);
+
+  // Make sure that the function has an instance prototype.
+  Label non_instance;
+  testb(FieldOperand(result, Map::kBitFieldOffset),
+        Immediate(1 << Map::kHasNonInstancePrototype));
+  j(not_zero, &non_instance);
+
+  // Get the prototype or initial map from the function.
+  movq(result,
+       FieldOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
+
+  // If the prototype or initial map is the hole, don't return it and
+  // simply miss the cache instead. This will allow us to allocate a
+  // prototype object on-demand in the runtime system.
+  CompareRoot(result, Heap::kTheHoleValueRootIndex);
+  j(equal, miss);
+
+  // If the function does not have an initial map, we're done.
+  Label done;
+  CmpObjectType(result, MAP_TYPE, kScratchRegister);
+  j(not_equal, &done);
+
+  // Get the prototype from the initial map.
+  movq(result, FieldOperand(result, Map::kPrototypeOffset));
+  jmp(&done);
+
+  // Non-instance prototype: Fetch prototype from constructor field
+  // in initial map.
+  bind(&non_instance);
+  movq(result, FieldOperand(result, Map::kConstructorOffset));
+
+  // All done.
+  bind(&done);
+}
+
+
+void MacroAssembler::SetCounter(StatsCounter* counter, int value) {
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    movq(kScratchRegister, ExternalReference(counter));
+    movl(Operand(kScratchRegister, 0), Immediate(value));
+  }
+}
+
+
+void MacroAssembler::IncrementCounter(StatsCounter* counter, int value) {
+  ASSERT(value > 0);
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    movq(kScratchRegister, ExternalReference(counter));
+    Operand operand(kScratchRegister, 0);
+    if (value == 1) {
+      incl(operand);
+    } else {
+      addl(operand, Immediate(value));
+    }
+  }
+}
+
+
+void MacroAssembler::DecrementCounter(StatsCounter* counter, int value) {
+  ASSERT(value > 0);
+  if (FLAG_native_code_counters && counter->Enabled()) {
+    movq(kScratchRegister, ExternalReference(counter));
+    Operand operand(kScratchRegister, 0);
+    if (value == 1) {
+      decl(operand);
+    } else {
+      subl(operand, Immediate(value));
+    }
+  }
+}
+
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+
+void MacroAssembler::PushRegistersFromMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Push the content of the memory location to the stack.
+  for (int i = 0; i < kNumJSCallerSaved; i++) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      movq(kScratchRegister, reg_addr);
+      push(Operand(kScratchRegister, 0));
+    }
+  }
+}
+
+void MacroAssembler::SaveRegistersToMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of registers to memory location.
+  for (int i = 0; i < kNumJSCallerSaved; i++) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      Register reg = { r };
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      movq(kScratchRegister, reg_addr);
+      movq(Operand(kScratchRegister, 0), reg);
+    }
+  }
+}
+
+
+void MacroAssembler::RestoreRegistersFromMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of memory location to registers.
+  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      Register reg = { r };
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      movq(kScratchRegister, reg_addr);
+      movq(reg, Operand(kScratchRegister, 0));
+    }
+  }
+}
+
+
+void MacroAssembler::PopRegistersToMemory(RegList regs) {
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Pop the content from the stack to the memory location.
+  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      movq(kScratchRegister, reg_addr);
+      pop(Operand(kScratchRegister, 0));
+    }
+  }
+}
+
+
+void MacroAssembler::CopyRegistersFromStackToMemory(Register base,
+                                                    Register scratch,
+                                                    RegList regs) {
+  ASSERT(!scratch.is(kScratchRegister));
+  ASSERT(!base.is(kScratchRegister));
+  ASSERT(!base.is(scratch));
+  ASSERT((regs & ~kJSCallerSaved) == 0);
+  // Copy the content of the stack to the memory location and adjust base.
+  for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
+    int r = JSCallerSavedCode(i);
+    if ((regs & (1 << r)) != 0) {
+      movq(scratch, Operand(base, 0));
+      ExternalReference reg_addr =
+          ExternalReference(Debug_Address::Register(i));
+      movq(kScratchRegister, reg_addr);
+      movq(Operand(kScratchRegister, 0), scratch);
+      lea(base, Operand(base, kPointerSize));
+    }
+  }
+}
+
+#endif  // ENABLE_DEBUGGER_SUPPORT
+
+
+void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id, InvokeFlag flag) {
+  bool resolved;
+  Handle<Code> code = ResolveBuiltin(id, &resolved);
+
+  // Calls are not allowed in some stubs.
+  ASSERT(flag == JUMP_FUNCTION || allow_stub_calls());
+
+  // Rely on the assertion to check that the number of provided
+  // arguments match the expected number of arguments. Fake a
+  // parameter count to avoid emitting code to do the check.
+  ParameterCount expected(0);
+  InvokeCode(Handle<Code>(code), expected, expected,
+             RelocInfo::CODE_TARGET, flag);
+
+  const char* name = Builtins::GetName(id);
+  int argc = Builtins::GetArgumentsCount(id);
+  // The target address for the jump is stored as an immediate at offset
+  // kInvokeCodeAddressOffset.
+  if (!resolved) {
+    uint32_t flags =
+        Bootstrapper::FixupFlagsArgumentsCount::encode(argc) |
+        Bootstrapper::FixupFlagsIsPCRelative::encode(false) |
+        Bootstrapper::FixupFlagsUseCodeObject::encode(false);
+    Unresolved entry =
+        { pc_offset() - kCallTargetAddressOffset, flags, name };
+    unresolved_.Add(entry);
+  }
+}
+
+
+void MacroAssembler::InvokePrologue(const ParameterCount& expected,
+                                    const ParameterCount& actual,
+                                    Handle<Code> code_constant,
+                                    Register code_register,
+                                    Label* done,
+                                    InvokeFlag flag) {
+  bool definitely_matches = false;
+  Label invoke;
+  if (expected.is_immediate()) {
+    ASSERT(actual.is_immediate());
+    if (expected.immediate() == actual.immediate()) {
+      definitely_matches = true;
+    } else {
+      movq(rax, Immediate(actual.immediate()));
+      if (expected.immediate() ==
+          SharedFunctionInfo::kDontAdaptArgumentsSentinel) {
+        // Don't worry about adapting arguments for built-ins that
+        // don't want that done. Skip adaption code by making it look
+        // like we have a match between expected and actual number of
+        // arguments.
+        definitely_matches = true;
+      } else {
+        movq(rbx, Immediate(expected.immediate()));
+      }
+    }
+  } else {
+    if (actual.is_immediate()) {
+      // Expected is in register, actual is immediate. This is the
+      // case when we invoke function values without going through the
+      // IC mechanism.
+      cmpq(expected.reg(), Immediate(actual.immediate()));
+      j(equal, &invoke);
+      ASSERT(expected.reg().is(rbx));
+      movq(rax, Immediate(actual.immediate()));
+    } else if (!expected.reg().is(actual.reg())) {
+      // Both expected and actual are in (different) registers. This
+      // is the case when we invoke functions using call and apply.
+      cmpq(expected.reg(), actual.reg());
+      j(equal, &invoke);
+      ASSERT(actual.reg().is(rax));
+      ASSERT(expected.reg().is(rbx));
+    }
+  }
+
+  if (!definitely_matches) {
+    Handle<Code> adaptor =
+        Handle<Code>(Builtins::builtin(Builtins::ArgumentsAdaptorTrampoline));
+    if (!code_constant.is_null()) {
+      movq(rdx, code_constant, RelocInfo::EMBEDDED_OBJECT);
+      addq(rdx, Immediate(Code::kHeaderSize - kHeapObjectTag));
+    } else if (!code_register.is(rdx)) {
+      movq(rdx, code_register);
+    }
+
+    if (flag == CALL_FUNCTION) {
+      Call(adaptor, RelocInfo::CODE_TARGET);
+      jmp(done);
+    } else {
+      Jump(adaptor, RelocInfo::CODE_TARGET);
+    }
+    bind(&invoke);
+  }
+}
+
+
+void MacroAssembler::InvokeCode(Register code,
+                                const ParameterCount& expected,
+                                const ParameterCount& actual,
+                                InvokeFlag flag) {
+  Label done;
+  InvokePrologue(expected, actual, Handle<Code>::null(), code, &done, flag);
+  if (flag == CALL_FUNCTION) {
+    call(code);
+  } else {
+    ASSERT(flag == JUMP_FUNCTION);
+    jmp(code);
+  }
+  bind(&done);
+}
+
+
+void MacroAssembler::InvokeCode(Handle<Code> code,
+                                const ParameterCount& expected,
+                                const ParameterCount& actual,
+                                RelocInfo::Mode rmode,
+                                InvokeFlag flag) {
+  Label done;
+  Register dummy = rax;
+  InvokePrologue(expected, actual, code, dummy, &done, flag);
+  if (flag == CALL_FUNCTION) {
+    Call(code, rmode);
+  } else {
+    ASSERT(flag == JUMP_FUNCTION);
+    Jump(code, rmode);
+  }
+  bind(&done);
+}
+
+
+void MacroAssembler::InvokeFunction(Register function,
+                                    const ParameterCount& actual,
+                                    InvokeFlag flag) {
+  ASSERT(function.is(rdi));
+  movq(rdx, FieldOperand(function, JSFunction::kSharedFunctionInfoOffset));
+  movq(rsi, FieldOperand(function, JSFunction::kContextOffset));
+  movsxlq(rbx,
+          FieldOperand(rdx, SharedFunctionInfo::kFormalParameterCountOffset));
+  movq(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset));
+  // Advances rdx to the end of the Code object header, to the start of
+  // the executable code.
+  lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
+
+  ParameterCount expected(rbx);
+  InvokeCode(rdx, expected, actual, flag);
+}
+
+
+void MacroAssembler::EnterFrame(StackFrame::Type type) {
+  push(rbp);
+  movq(rbp, rsp);
+  push(rsi);  // Context.
+  push(Immediate(Smi::FromInt(type)));
+  movq(kScratchRegister, CodeObject(), RelocInfo::EMBEDDED_OBJECT);
+  push(kScratchRegister);
+  if (FLAG_debug_code) {
+    movq(kScratchRegister,
+         Factory::undefined_value(),
+         RelocInfo::EMBEDDED_OBJECT);
+    cmpq(Operand(rsp, 0), kScratchRegister);
+    Check(not_equal, "code object not properly patched");
+  }
+}
+
+
+void MacroAssembler::LeaveFrame(StackFrame::Type type) {
+  if (FLAG_debug_code) {
+    movq(kScratchRegister, Immediate(Smi::FromInt(type)));
+    cmpq(Operand(rbp, StandardFrameConstants::kMarkerOffset), kScratchRegister);
+    Check(equal, "stack frame types must match");
+  }
+  movq(rsp, rbp);
+  pop(rbp);
+}
+
+
+
+void MacroAssembler::EnterExitFrame(StackFrame::Type type, int result_size) {
+  ASSERT(type == StackFrame::EXIT || type == StackFrame::EXIT_DEBUG);
+
+  // Setup the frame structure on the stack.
+  // All constants are relative to the frame pointer of the exit frame.
+  ASSERT(ExitFrameConstants::kCallerSPDisplacement == +2 * kPointerSize);
+  ASSERT(ExitFrameConstants::kCallerPCOffset == +1 * kPointerSize);
+  ASSERT(ExitFrameConstants::kCallerFPOffset ==  0 * kPointerSize);
+  push(rbp);
+  movq(rbp, rsp);
+
+  // Reserve room for entry stack pointer and push the debug marker.
+  ASSERT(ExitFrameConstants::kSPOffset  == -1 * kPointerSize);
+  push(Immediate(0));  // saved entry sp, patched before call
+  push(Immediate(type == StackFrame::EXIT_DEBUG ? 1 : 0));
+
+  // Save the frame pointer and the context in top.
+  ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+  ExternalReference context_address(Top::k_context_address);
+  movq(r14, rax);  // Backup rax before we use it.
+
+  movq(rax, rbp);
+  store_rax(c_entry_fp_address);
+  movq(rax, rsi);
+  store_rax(context_address);
+
+  // Setup argv in callee-saved register r15. It is reused in LeaveExitFrame,
+  // so it must be retained across the C-call.
+  int offset = StandardFrameConstants::kCallerSPOffset - kPointerSize;
+  lea(r15, Operand(rbp, r14, times_pointer_size, offset));
+
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  // Save the state of all registers to the stack from the memory
+  // location. This is needed to allow nested break points.
+  if (type == StackFrame::EXIT_DEBUG) {
+    // TODO(1243899): This should be symmetric to
+    // CopyRegistersFromStackToMemory() but it isn't! esp is assumed
+    // correct here, but computed for the other call. Very error
+    // prone! FIX THIS.  Actually there are deeper problems with
+    // register saving than this asymmetry (see the bug report
+    // associated with this issue).
+    PushRegistersFromMemory(kJSCallerSaved);
+  }
+#endif
+
+#ifdef _WIN64
+  // Reserve space on stack for result and argument structures, if necessary.
+  int result_stack_space = (result_size < 2) ? 0 : result_size * kPointerSize;
+  // Reserve space for the Arguments object.  The Windows 64-bit ABI
+  // requires us to pass this structure as a pointer to its location on
+  // the stack.  The structure contains 2 values.
+  int argument_stack_space = 2 * kPointerSize;
+  // We also need backing space for 4 parameters, even though
+  // we only pass one or two parameter, and it is in a register.
+  int argument_mirror_space = 4 * kPointerSize;
+  int total_stack_space =
+      argument_mirror_space + argument_stack_space + result_stack_space;
+  subq(rsp, Immediate(total_stack_space));
+#endif
+
+  // Get the required frame alignment for the OS.
+  static const int kFrameAlignment = OS::ActivationFrameAlignment();
+  if (kFrameAlignment > 0) {
+    ASSERT(IsPowerOf2(kFrameAlignment));
+    movq(kScratchRegister, Immediate(-kFrameAlignment));
+    and_(rsp, kScratchRegister);
+  }
+
+  // Patch the saved entry sp.
+  movq(Operand(rbp, ExitFrameConstants::kSPOffset), rsp);
+}
+
+
+void MacroAssembler::LeaveExitFrame(StackFrame::Type type, int result_size) {
+  // Registers:
+  // r15 : argv
+#ifdef ENABLE_DEBUGGER_SUPPORT
+  // Restore the memory copy of the registers by digging them out from
+  // the stack. This is needed to allow nested break points.
+  if (type == StackFrame::EXIT_DEBUG) {
+    // It's okay to clobber register rbx below because we don't need
+    // the function pointer after this.
+    const int kCallerSavedSize = kNumJSCallerSaved * kPointerSize;
+    int kOffset = ExitFrameConstants::kDebugMarkOffset - kCallerSavedSize;
+    lea(rbx, Operand(rbp, kOffset));
+    CopyRegistersFromStackToMemory(rbx, rcx, kJSCallerSaved);
+  }
+#endif
+
+  // Get the return address from the stack and restore the frame pointer.
+  movq(rcx, Operand(rbp, 1 * kPointerSize));
+  movq(rbp, Operand(rbp, 0 * kPointerSize));
+
+#ifdef _WIN64
+  // If return value is on the stack, pop it to registers.
+  if (result_size > 1) {
+    ASSERT_EQ(2, result_size);
+    // Position above 4 argument mirrors and arguments object.
+    movq(rax, Operand(rsp, 6 * kPointerSize));
+    movq(rdx, Operand(rsp, 7 * kPointerSize));
+  }
+#endif
+
+  // Pop everything up to and including the arguments and the receiver
+  // from the caller stack.
+  lea(rsp, Operand(r15, 1 * kPointerSize));
+
+  // Restore current context from top and clear it in debug mode.
+  ExternalReference context_address(Top::k_context_address);
+  movq(kScratchRegister, context_address);
+  movq(rsi, Operand(kScratchRegister, 0));
+#ifdef DEBUG
+  movq(Operand(kScratchRegister, 0), Immediate(0));
+#endif
+
+  // Push the return address to get ready to return.
+  push(rcx);
+
+  // Clear the top frame.
+  ExternalReference c_entry_fp_address(Top::k_c_entry_fp_address);
+  movq(kScratchRegister, c_entry_fp_address);
+  movq(Operand(kScratchRegister, 0), Immediate(0));
+}
+
+
+Register MacroAssembler::CheckMaps(JSObject* object, Register object_reg,
+                                   JSObject* holder, Register holder_reg,
+                                   Register scratch,
+                                   Label* miss) {
+  // Make sure there's no overlap between scratch and the other
+  // registers.
+  ASSERT(!scratch.is(object_reg) && !scratch.is(holder_reg));
+
+  // Keep track of the current object in register reg.  On the first
+  // iteration, reg is an alias for object_reg, on later iterations,
+  // it is an alias for holder_reg.
+  Register reg = object_reg;
+  int depth = 1;
+
+  // Check the maps in the prototype chain.
+  // Traverse the prototype chain from the object and do map checks.
+  while (object != holder) {
+    depth++;
+
+    // Only global objects and objects that do not require access
+    // checks are allowed in stubs.
+    ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
+
+    JSObject* prototype = JSObject::cast(object->GetPrototype());
+    if (Heap::InNewSpace(prototype)) {
+      // Get the map of the current object.
+      movq(scratch, FieldOperand(reg, HeapObject::kMapOffset));
+      Cmp(scratch, Handle<Map>(object->map()));
+      // Branch on the result of the map check.
+      j(not_equal, miss);
+      // Check access rights to the global object.  This has to happen
+      // after the map check so that we know that the object is
+      // actually a global object.
+      if (object->IsJSGlobalProxy()) {
+        CheckAccessGlobalProxy(reg, scratch, miss);
+
+        // Restore scratch register to be the map of the object.
+        // We load the prototype from the map in the scratch register.
+        movq(scratch, FieldOperand(reg, HeapObject::kMapOffset));
+      }
+      // The prototype is in new space; we cannot store a reference
+      // to it in the code. Load it from the map.
+      reg = holder_reg;  // from now the object is in holder_reg
+      movq(reg, FieldOperand(scratch, Map::kPrototypeOffset));
+
+    } else {
+      // Check the map of the current object.
+      Cmp(FieldOperand(reg, HeapObject::kMapOffset),
+          Handle<Map>(object->map()));
+      // Branch on the result of the map check.
+      j(not_equal, miss);
+      // Check access rights to the global object.  This has to happen
+      // after the map check so that we know that the object is
+      // actually a global object.
+      if (object->IsJSGlobalProxy()) {
+        CheckAccessGlobalProxy(reg, scratch, miss);
+      }
+      // The prototype is in old space; load it directly.
+      reg = holder_reg;  // from now the object is in holder_reg
+      Move(reg, Handle<JSObject>(prototype));
+    }
+
+    // Go to the next object in the prototype chain.
+    object = prototype;
+  }
+
+  // Check the holder map.
+  Cmp(FieldOperand(reg, HeapObject::kMapOffset),
+      Handle<Map>(holder->map()));
+  j(not_equal, miss);
+
+  // Log the check depth.
+  LOG(IntEvent("check-maps-depth", depth));
+
+  // Perform security check for access to the global object and return
+  // the holder register.
+  ASSERT(object == holder);
+  ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
+  if (object->IsJSGlobalProxy()) {
+    CheckAccessGlobalProxy(reg, scratch, miss);
+  }
+  return reg;
+}
+
+
+
+
+void MacroAssembler::CheckAccessGlobalProxy(Register holder_reg,
+                                            Register scratch,
+                                            Label* miss) {
+  Label same_contexts;
+
+  ASSERT(!holder_reg.is(scratch));
+  ASSERT(!scratch.is(kScratchRegister));
+  // Load current lexical context from the stack frame.
+  movq(scratch, Operand(rbp, StandardFrameConstants::kContextOffset));
+
+  // When generating debug code, make sure the lexical context is set.
+  if (FLAG_debug_code) {
+    cmpq(scratch, Immediate(0));
+    Check(not_equal, "we should not have an empty lexical context");
+  }
+  // Load the global context of the current context.
+  int offset = Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
+  movq(scratch, FieldOperand(scratch, offset));
+  movq(scratch, FieldOperand(scratch, GlobalObject::kGlobalContextOffset));
+
+  // Check the context is a global context.
+  if (FLAG_debug_code) {
+    Cmp(FieldOperand(scratch, HeapObject::kMapOffset),
+        Factory::global_context_map());
+    Check(equal, "JSGlobalObject::global_context should be a global context.");
+  }
+
+  // Check if both contexts are the same.
+  cmpq(scratch, FieldOperand(holder_reg, JSGlobalProxy::kContextOffset));
+  j(equal, &same_contexts);
+
+  // Compare security tokens.
+  // Check that the security token in the calling global object is
+  // compatible with the security token in the receiving global
+  // object.
+
+  // Check the context is a global context.
+  if (FLAG_debug_code) {
+    // Preserve original value of holder_reg.
+    push(holder_reg);
+    movq(holder_reg, FieldOperand(holder_reg, JSGlobalProxy::kContextOffset));
+    CompareRoot(holder_reg, Heap::kNullValueRootIndex);
+    Check(not_equal, "JSGlobalProxy::context() should not be null.");
+
+    // Read the first word and compare to global_context_map(),
+    movq(holder_reg, FieldOperand(holder_reg, HeapObject::kMapOffset));
+    CompareRoot(holder_reg, Heap::kGlobalContextMapRootIndex);
+    Check(equal, "JSGlobalObject::global_context should be a global context.");
+    pop(holder_reg);
+  }
+
+  movq(kScratchRegister,
+       FieldOperand(holder_reg, JSGlobalProxy::kContextOffset));
+  int token_offset = Context::kHeaderSize +
+                     Context::SECURITY_TOKEN_INDEX * kPointerSize;
+  movq(scratch, FieldOperand(scratch, token_offset));
+  cmpq(scratch, FieldOperand(kScratchRegister, token_offset));
+  j(not_equal, miss);
+
+  bind(&same_contexts);
+}
+
+
+void MacroAssembler::LoadAllocationTopHelper(Register result,
+                                             Register result_end,
+                                             Register scratch,
+                                             AllocationFlags flags) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Just return if allocation top is already known.
+  if ((flags & RESULT_CONTAINS_TOP) != 0) {
+    // No use of scratch if allocation top is provided.
+    ASSERT(scratch.is(no_reg));
+#ifdef DEBUG
+    // Assert that result actually contains top on entry.
+    movq(kScratchRegister, new_space_allocation_top);
+    cmpq(result, Operand(kScratchRegister, 0));
+    Check(equal, "Unexpected allocation top");
+#endif
+    return;
+  }
+
+  // Move address of new object to result. Use scratch register if available.
+  if (scratch.is(no_reg)) {
+    movq(kScratchRegister, new_space_allocation_top);
+    movq(result, Operand(kScratchRegister, 0));
+  } else {
+    ASSERT(!scratch.is(result_end));
+    movq(scratch, new_space_allocation_top);
+    movq(result, Operand(scratch, 0));
+  }
+}
+
+
+void MacroAssembler::UpdateAllocationTopHelper(Register result_end,
+                                               Register scratch) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Update new top.
+  if (result_end.is(rax)) {
+    // rax can be stored directly to a memory location.
+    store_rax(new_space_allocation_top);
+  } else {
+    // Register required - use scratch provided if available.
+    if (scratch.is(no_reg)) {
+      movq(kScratchRegister, new_space_allocation_top);
+      movq(Operand(kScratchRegister, 0), result_end);
+    } else {
+      movq(Operand(scratch, 0), result_end);
+    }
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(int object_size,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  ASSERT(!result.is(result_end));
+
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  lea(result_end, Operand(result, object_size));
+  movq(kScratchRegister, new_space_allocation_limit);
+  cmpq(result_end, Operand(kScratchRegister, 0));
+  j(above, gc_required);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag the result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    addq(result, Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(int header_size,
+                                        ScaleFactor element_size,
+                                        Register element_count,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  ASSERT(!result.is(result_end));
+
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  lea(result_end, Operand(result, element_count, element_size, header_size));
+  movq(kScratchRegister, new_space_allocation_limit);
+  cmpq(result_end, Operand(kScratchRegister, 0));
+  j(above, gc_required);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag the result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    addq(result, Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::AllocateInNewSpace(Register object_size,
+                                        Register result,
+                                        Register result_end,
+                                        Register scratch,
+                                        Label* gc_required,
+                                        AllocationFlags flags) {
+  // Load address of new object into result.
+  LoadAllocationTopHelper(result, result_end, scratch, flags);
+
+  // Calculate new top and bail out if new space is exhausted.
+  ExternalReference new_space_allocation_limit =
+      ExternalReference::new_space_allocation_limit_address();
+  if (!object_size.is(result_end)) {
+    movq(result_end, object_size);
+  }
+  addq(result_end, result);
+  movq(kScratchRegister, new_space_allocation_limit);
+  cmpq(result_end, Operand(kScratchRegister, 0));
+  j(above, gc_required);
+
+  // Update allocation top.
+  UpdateAllocationTopHelper(result_end, scratch);
+
+  // Tag the result if requested.
+  if ((flags & TAG_OBJECT) != 0) {
+    addq(result, Immediate(kHeapObjectTag));
+  }
+}
+
+
+void MacroAssembler::UndoAllocationInNewSpace(Register object) {
+  ExternalReference new_space_allocation_top =
+      ExternalReference::new_space_allocation_top_address();
+
+  // Make sure the object has no tag before resetting top.
+  and_(object, Immediate(~kHeapObjectTagMask));
+  movq(kScratchRegister, new_space_allocation_top);
+#ifdef DEBUG
+  cmpq(object, Operand(kScratchRegister, 0));
+  Check(below, "Undo allocation of non allocated memory");
+#endif
+  movq(Operand(kScratchRegister, 0), object);
+}
+
+
+CodePatcher::CodePatcher(byte* address, int size)
+    : address_(address), size_(size), masm_(address, size + Assembler::kGap) {
+  // Create a new macro assembler pointing to the address of the code to patch.
+  // The size is adjusted with kGap on order for the assembler to generate size
+  // bytes of instructions without failing with buffer size constraints.
+  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
+}
+
+
+CodePatcher::~CodePatcher() {
+  // Indicate that code has changed.
+  CPU::FlushICache(address_, size_);
+
+  // Check that the code was patched as expected.
+  ASSERT(masm_.pc_ == address_ + size_);
+  ASSERT(masm_.reloc_info_writer.pos() == address_ + size_ + Assembler::kGap);
+}
+
+
+} }  // namespace v8::internal