Roll V8 back to 3.6

Roll back to V8 3.6 to fix x86 build, we don't have ucontext.h.

This reverts commits:
5d4cdbf7a67d3662fa0bee4efdb7edd8daec9b0b
c7cc028aaeedbbfa11c11d0b7b243b3d9e837ed9
592a9fc1d8ea420377a2e7efd0600e20b058be2b

Bug: 5688872
Change-Id: Ic961bb5e65b778e98bbfb71cce71d99fa949e995
diff --git a/src/contexts.cc b/src/contexts.cc
index 76784bd..4f93abd 100644
--- a/src/contexts.cc
+++ b/src/contexts.cc
@@ -86,14 +86,14 @@
 
 Handle<Object> Context::Lookup(Handle<String> name,
                                ContextLookupFlags flags,
-                               int* index,
+                               int* index_,
                                PropertyAttributes* attributes,
                                BindingFlags* binding_flags) {
   Isolate* isolate = GetIsolate();
   Handle<Context> context(this, isolate);
 
   bool follow_context_chain = (flags & FOLLOW_CONTEXT_CHAIN) != 0;
-  *index = -1;
+  *index_ = -1;
   *attributes = ABSENT;
   *binding_flags = MISSING_BINDING;
 
@@ -110,51 +110,70 @@
       PrintF("\n");
     }
 
-    // 1. Check global objects, subjects of with, and extension objects.
-    if (context->IsGlobalContext() ||
-        context->IsWithContext() ||
-        (context->IsFunctionContext() && context->has_extension())) {
-      Handle<JSObject> object(JSObject::cast(context->extension()), isolate);
-      // Context extension objects needs to behave as if they have no
-      // prototype.  So even if we want to follow prototype chains, we need
-      // to only do a local lookup for context extension objects.
-      if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0 ||
-          object->IsJSContextExtensionObject()) {
-        *attributes = object->GetLocalPropertyAttribute(*name);
-      } else {
-        *attributes = object->GetPropertyAttribute(*name);
-      }
-      if (*attributes != ABSENT) {
-        if (FLAG_trace_contexts) {
-          PrintF("=> found property in context object %p\n",
-                 reinterpret_cast<void*>(*object));
+    // Check extension/with/global object.
+    if (!context->IsBlockContext() && context->has_extension()) {
+      if (context->IsCatchContext()) {
+        // Catch contexts have the variable name in the extension slot.
+        if (name->Equals(String::cast(context->extension()))) {
+          if (FLAG_trace_contexts) {
+            PrintF("=> found in catch context\n");
+          }
+          *index_ = Context::THROWN_OBJECT_INDEX;
+          *attributes = NONE;
+          *binding_flags = MUTABLE_IS_INITIALIZED;
+          return context;
         }
-        return object;
+      } else {
+        ASSERT(context->IsGlobalContext() ||
+               context->IsFunctionContext() ||
+               context->IsWithContext());
+        // Global, function, and with contexts may have an object in the
+        // extension slot.
+        Handle<JSObject> extension(JSObject::cast(context->extension()),
+                                   isolate);
+        // Context extension objects needs to behave as if they have no
+        // prototype.  So even if we want to follow prototype chains, we
+        // need to only do a local lookup for context extension objects.
+        if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0 ||
+            extension->IsJSContextExtensionObject()) {
+          *attributes = extension->GetLocalPropertyAttribute(*name);
+        } else {
+          *attributes = extension->GetPropertyAttribute(*name);
+        }
+        if (*attributes != ABSENT) {
+          // property found
+          if (FLAG_trace_contexts) {
+            PrintF("=> found property in context object %p\n",
+                   reinterpret_cast<void*>(*extension));
+          }
+          return extension;
+        }
       }
     }
 
-    // 2. Check the context proper if it has slots.
+    // Check serialized scope information of functions and blocks. Only
+    // functions can have parameters, and a function name.
     if (context->IsFunctionContext() || context->IsBlockContext()) {
-      // Use serialized scope information of functions and blocks to search
-      // for the context index.
-      Handle<ScopeInfo> scope_info;
+      // We may have context-local slots.  Check locals in the context.
+      Handle<SerializedScopeInfo> scope_info;
       if (context->IsFunctionContext()) {
-        scope_info = Handle<ScopeInfo>(
+        scope_info = Handle<SerializedScopeInfo>(
             context->closure()->shared()->scope_info(), isolate);
       } else {
-        scope_info = Handle<ScopeInfo>(
-            ScopeInfo::cast(context->extension()), isolate);
+        ASSERT(context->IsBlockContext());
+        scope_info = Handle<SerializedScopeInfo>(
+            SerializedScopeInfo::cast(context->extension()), isolate);
       }
-      VariableMode mode;
-      InitializationFlag init_flag;
-      int slot_index = scope_info->ContextSlotIndex(*name, &mode, &init_flag);
-      ASSERT(slot_index < 0 || slot_index >= MIN_CONTEXT_SLOTS);
-      if (slot_index >= 0) {
+
+      Variable::Mode mode;
+      int index = scope_info->ContextSlotIndex(*name, &mode);
+      ASSERT(index < 0 || index >= MIN_CONTEXT_SLOTS);
+      if (index >= 0) {
         if (FLAG_trace_contexts) {
           PrintF("=> found local in context slot %d (mode = %d)\n",
-                 slot_index, mode);
+                 index, mode);
         }
-        *index = slot_index;
+        *index_ = index;
         // Note: Fixed context slots are statically allocated by the compiler.
         // Statically allocated variables always have a statically known mode,
         // which is the mode with which they were declared when added to the
@@ -162,31 +181,23 @@
         // declared variables that were introduced through declaration nodes)
         // must not appear here.
         switch (mode) {
-          case INTERNAL:  // Fall through.
-          case VAR:
+          case Variable::INTERNAL:  // Fall through.
+          case Variable::VAR:
             *attributes = NONE;
             *binding_flags = MUTABLE_IS_INITIALIZED;
             break;
-          case LET:
+          case Variable::LET:
             *attributes = NONE;
-            *binding_flags = (init_flag == kNeedsInitialization)
-                ? MUTABLE_CHECK_INITIALIZED : MUTABLE_IS_INITIALIZED;
+            *binding_flags = MUTABLE_CHECK_INITIALIZED;
             break;
-          case CONST:
+          case Variable::CONST:
             *attributes = READ_ONLY;
-            *binding_flags = (init_flag == kNeedsInitialization)
-                ? IMMUTABLE_CHECK_INITIALIZED : IMMUTABLE_IS_INITIALIZED;
+            *binding_flags = IMMUTABLE_CHECK_INITIALIZED;
             break;
-          case CONST_HARMONY:
-            *attributes = READ_ONLY;
-            *binding_flags = (init_flag == kNeedsInitialization)
-                ? IMMUTABLE_CHECK_INITIALIZED_HARMONY :
-                IMMUTABLE_IS_INITIALIZED_HARMONY;
-            break;
-          case DYNAMIC:
-          case DYNAMIC_GLOBAL:
-          case DYNAMIC_LOCAL:
-          case TEMPORARY:
+          case Variable::DYNAMIC:
+          case Variable::DYNAMIC_GLOBAL:
+          case Variable::DYNAMIC_LOCAL:
+          case Variable::TEMPORARY:
             UNREACHABLE();
             break;
         }
@@ -195,37 +206,22 @@
 
       // Check the slot corresponding to the intermediate context holding
       // only the function name variable.
-      if (follow_context_chain && context->IsFunctionContext()) {
-        VariableMode mode;
-        int function_index = scope_info->FunctionContextSlotIndex(*name, &mode);
-        if (function_index >= 0) {
+      if (follow_context_chain) {
+        int index = scope_info->FunctionContextSlotIndex(*name);
+        if (index >= 0) {
           if (FLAG_trace_contexts) {
             PrintF("=> found intermediate function in context slot %d\n",
-                   function_index);
+                   index);
           }
-          *index = function_index;
+          *index_ = index;
           *attributes = READ_ONLY;
-          ASSERT(mode == CONST || mode == CONST_HARMONY);
-          *binding_flags = (mode == CONST)
-              ? IMMUTABLE_IS_INITIALIZED : IMMUTABLE_IS_INITIALIZED_HARMONY;
+          *binding_flags = IMMUTABLE_IS_INITIALIZED;
           return context;
         }
       }
-
-    } else if (context->IsCatchContext()) {
-      // Catch contexts have the variable name in the extension slot.
-      if (name->Equals(String::cast(context->extension()))) {
-        if (FLAG_trace_contexts) {
-          PrintF("=> found in catch context\n");
-        }
-        *index = Context::THROWN_OBJECT_INDEX;
-        *attributes = NONE;
-        *binding_flags = MUTABLE_IS_INITIALIZED;
-        return context;
-      }
     }
 
-    // 3. Prepare to continue with the previous (next outermost) context.
+    // Proceed with the previous context.
     if (context->IsGlobalContext()) {
       follow_context_chain = false;
     } else {
@@ -240,6 +236,68 @@
 }
 
 
+bool Context::GlobalIfNotShadowedByEval(Handle<String> name) {
+  Context* context = this;
+
+  // Check that there is no local with the given name in contexts
+  // before the global context and check that there are no context
+  // extension objects (conservative check for with statements).
+  while (!context->IsGlobalContext()) {
+    // Check if the context is a catch or with context, or has introduced
+    // bindings by calling non-strict eval.
+    if (context->has_extension()) return false;
+
+    // Not a with context so it must be a function context.
+    ASSERT(context->IsFunctionContext());
+
+    // Check non-parameter locals.
+    Handle<SerializedScopeInfo> scope_info(
+        context->closure()->shared()->scope_info());
+    Variable::Mode mode;
+    int index = scope_info->ContextSlotIndex(*name, &mode);
+    ASSERT(index < 0 || index >= MIN_CONTEXT_SLOTS);
+    if (index >= 0) return false;
+
+    // Check parameter locals.
+    int param_index = scope_info->ParameterIndex(*name);
+    if (param_index >= 0) return false;
+
+    // Check context only holding the function name variable.
+    index = scope_info->FunctionContextSlotIndex(*name);
+    if (index >= 0) return false;
+    context = context->previous();
+  }
+
+  // No local or potential with statement found so the variable is
+  // global unless it is shadowed by an eval-introduced variable.
+  return true;
+}
+
+
+void Context::ComputeEvalScopeInfo(bool* outer_scope_calls_eval,
+                                   bool* outer_scope_calls_non_strict_eval) {
+  // Skip up the context chain checking all the function contexts to see
+  // whether they call eval.
+  Context* context = this;
+  while (!context->IsGlobalContext()) {
+    if (context->IsFunctionContext()) {
+      Handle<SerializedScopeInfo> scope_info(
+          context->closure()->shared()->scope_info());
+      if (scope_info->CallsEval()) {
+        *outer_scope_calls_eval = true;
+        if (!scope_info->IsStrictMode()) {
+          // No need to go further since the answers will not change from
+          // here.
+          *outer_scope_calls_non_strict_eval = true;
+          return;
+        }
+      }
+    }
+    context = context->previous();
+  }
+}
+
+
 void Context::AddOptimizedFunction(JSFunction* function) {
   ASSERT(IsGlobalContext());
 #ifdef DEBUG