Update V8

Change-Id: I7a9da7dbb2116a441788407d60ed10155cded941
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>

1 files changed, 1871 insertions, 0 deletions

diff --git a/src/v8/0004-Introduce-a-QML-compilation-mode.patch b/src/v8/0004-Introduce-a-QML-compilation-mode.patch
new file mode 100644
index 0000000000..4b79d94e68
--- /dev/null
+++ b/src/v8/0004-Introduce-a-QML-compilation-mode.patch
@@ -0,0 +1,1871 @@
+From 27ef7b7b37255a9965fe31fb7597720f57ed5154 Mon Sep 17 00:00:00 2001
+From: Aaron Kennedy <aaron.kennedy@nokia.com>
+Date: Wed, 5 Oct 2011 13:01:30 +1000
+Subject: [PATCH 04/11] Introduce a QML compilation mode
+
+In QML mode, there is a second global object - known as the QML
+global object.  During property resolution, if a property is not
+present on the JS global object, it is resolve on the QML global
+object.
+
+This global object behavior is only enabled if a script is being
+compiled in QML mode.  The object to use as the QML global object
+is passed as a parameter to the Script::Run() method.  Any function
+closures etc. created during the run will retain a reference to this
+object, so different objects can be passed in different script
+runs.
+---
+ include/v8.h                     |   19 ++++++++--
+ src/api.cc                       |   52 ++++++++++++++++++++++++-----
+ src/arm/code-stubs-arm.cc        |    4 ++
+ src/arm/full-codegen-arm.cc      |   28 +++++++++-------
+ src/arm/lithium-arm.cc           |    2 +-
+ src/arm/lithium-arm.h            |    6 +++-
+ src/arm/lithium-codegen-arm.cc   |    7 ++--
+ src/arm/macro-assembler-arm.h    |    5 +++
+ src/ast-inl.h                    |    5 +++
+ src/ast.h                        |    1 +
+ src/code-stubs.h                 |    2 +-
+ src/compiler.cc                  |   15 +++++++-
+ src/compiler.h                   |   16 +++++++--
+ src/contexts.cc                  |   35 +++++++++++++++++++
+ src/contexts.h                   |    4 ++
+ src/execution.cc                 |   31 ++++++++++++++---
+ src/execution.h                  |    8 ++++
+ src/full-codegen.cc              |    3 +-
+ src/full-codegen.h               |    1 +
+ src/heap.cc                      |    4 ++
+ src/hydrogen-instructions.h      |    8 ++++-
+ src/hydrogen.cc                  |    2 +
+ src/ia32/code-stubs-ia32.cc      |    5 +++
+ src/ia32/full-codegen-ia32.cc    |   28 +++++++++-------
+ src/ia32/lithium-codegen-ia32.cc |    7 ++--
+ src/ia32/lithium-ia32.cc         |    2 +-
+ src/ia32/lithium-ia32.h          |    6 +++-
+ src/ia32/macro-assembler-ia32.h  |    3 ++
+ src/objects-inl.h                |    2 +
+ src/objects.h                    |    4 ++
+ src/parser.cc                    |   27 +++++++++++++--
+ src/parser.h                     |    4 ++-
+ src/prettyprinter.cc             |    3 ++
+ src/runtime.cc                   |   68 +++++++++++++++++++++++++-------------
+ src/runtime.h                    |    8 ++--
+ src/scopes.cc                    |   61 ++++++++++++++++++++++++++++++++++
+ src/scopes.h                     |    8 ++++
+ src/variables.cc                 |    3 +-
+ src/variables.h                  |    5 +++
+ src/x64/code-stubs-x64.cc        |    4 ++
+ src/x64/full-codegen-x64.cc      |   28 +++++++++-------
+ src/x64/lithium-codegen-x64.cc   |    7 ++--
+ src/x64/lithium-x64.cc           |    2 +-
+ src/x64/lithium-x64.h            |    6 +++
+ src/x64/macro-assembler-x64.h    |    5 +++
+ 45 files changed, 445 insertions(+), 109 deletions(-)
+
+diff --git a/include/v8.h b/include/v8.h
+index 3ef4dd6..193e2fe 100644
+--- a/include/v8.h
++++ b/include/v8.h
+@@ -587,6 +587,11 @@ class ScriptOrigin {
+  */
+ class V8EXPORT Script {
+  public:
++  enum CompileFlags {
++      Default = 0x00,
++      QmlMode = 0x01
++  };
++
+   /**
+    * Compiles the specified script (context-independent).
+    *
+@@ -605,7 +610,8 @@ class V8EXPORT Script {
+   static Local<Script> New(Handle<String> source,
+                            ScriptOrigin* origin = NULL,
+                            ScriptData* pre_data = NULL,
+-                           Handle<String> script_data = Handle<String>());
++                           Handle<String> script_data = Handle<String>(),
++                           CompileFlags = Default);
+ 
+   /**
+    * Compiles the specified script using the specified file name
+@@ -618,7 +624,8 @@ class V8EXPORT Script {
+    *   will use the currently entered context).
+    */
+   static Local<Script> New(Handle<String> source,
+-                           Handle<Value> file_name);
++                           Handle<Value> file_name,
++                           CompileFlags = Default);
+ 
+   /**
+    * Compiles the specified script (bound to current context).
+@@ -639,7 +646,8 @@ class V8EXPORT Script {
+   static Local<Script> Compile(Handle<String> source,
+                                ScriptOrigin* origin = NULL,
+                                ScriptData* pre_data = NULL,
+-                               Handle<String> script_data = Handle<String>());
++                               Handle<String> script_data = Handle<String>(),
++                               CompileFlags = Default);
+ 
+   /**
+    * Compiles the specified script using the specified file name
+@@ -656,7 +664,8 @@ class V8EXPORT Script {
+    */
+   static Local<Script> Compile(Handle<String> source,
+                                Handle<Value> file_name,
+-                               Handle<String> script_data = Handle<String>());
++                               Handle<String> script_data = Handle<String>(),
++                               CompileFlags = Default);
+ 
+   /**
+    * Runs the script returning the resulting value.  If the script is
+@@ -666,6 +675,7 @@ class V8EXPORT Script {
+    * compiled.
+    */
+   Local<Value> Run();
++  Local<Value> Run(Handle<Object> qml);
+ 
+   /**
+    * Returns the script id value.
+@@ -3506,6 +3516,7 @@ class V8EXPORT Context {
+    * JavaScript frames an empty handle is returned.
+    */
+   static Local<Context> GetCalling();
++  static Local<Object> GetCallingQmlGlobal();
+ 
+   /**
+    * Sets the security token for the context.  To access an object in
+diff --git a/src/api.cc b/src/api.cc
+index 85f0d4b..fd718c8 100644
+--- a/src/api.cc
++++ b/src/api.cc
+@@ -1514,7 +1514,8 @@ ScriptData* ScriptData::New(const char* data, int length) {
+ Local<Script> Script::New(v8::Handle<String> source,
+                           v8::ScriptOrigin* origin,
+                           v8::ScriptData* pre_data,
+-                          v8::Handle<String> script_data) {
++                          v8::Handle<String> script_data,
++                          v8::Script::CompileFlags compile_flags) {
+   i::Isolate* isolate = i::Isolate::Current();
+   ON_BAILOUT(isolate, "v8::Script::New()", return Local<Script>());
+   LOG_API(isolate, "Script::New");
+@@ -1551,7 +1552,8 @@ Local<Script> Script::New(v8::Handle<String> source,
+                            NULL,
+                            pre_data_impl,
+                            Utils::OpenHandle(*script_data),
+-                           i::NOT_NATIVES_CODE);
++                           i::NOT_NATIVES_CODE,
++                           compile_flags);
+   has_pending_exception = result.is_null();
+   EXCEPTION_BAILOUT_CHECK(isolate, Local<Script>());
+   return Local<Script>(ToApi<Script>(result));
+@@ -1559,21 +1561,23 @@ Local<Script> Script::New(v8::Handle<String> source,
+ 
+ 
+ Local<Script> Script::New(v8::Handle<String> source,
+-                          v8::Handle<Value> file_name) {
++                          v8::Handle<Value> file_name,
++                          v8::Script::CompileFlags compile_flags) {
+   ScriptOrigin origin(file_name);
+-  return New(source, &origin);
++  return New(source, &origin, 0, Handle<String>(), compile_flags);
+ }
+ 
+ 
+ Local<Script> Script::Compile(v8::Handle<String> source,
+                               v8::ScriptOrigin* origin,
+                               v8::ScriptData* pre_data,
+-                              v8::Handle<String> script_data) {
++                              v8::Handle<String> script_data,
++                              v8::Script::CompileFlags compile_flags) {
+   i::Isolate* isolate = i::Isolate::Current();
+   ON_BAILOUT(isolate, "v8::Script::Compile()", return Local<Script>());
+   LOG_API(isolate, "Script::Compile");
+   ENTER_V8(isolate);
+-  Local<Script> generic = New(source, origin, pre_data, script_data);
++  Local<Script> generic = New(source, origin, pre_data, script_data, compile_flags);
+   if (generic.IsEmpty())
+     return generic;
+   i::Handle<i::Object> obj = Utils::OpenHandle(*generic);
+@@ -1589,13 +1593,18 @@ Local<Script> Script::Compile(v8::Handle<String> source,
+ 
+ Local<Script> Script::Compile(v8::Handle<String> source,
+                               v8::Handle<Value> file_name,
+-                              v8::Handle<String> script_data) {
++                              v8::Handle<String> script_data,
++                              v8::Script::CompileFlags compile_flags) {
+   ScriptOrigin origin(file_name);
+-  return Compile(source, &origin, 0, script_data);
++  return Compile(source, &origin, 0, script_data, compile_flags);
+ }
+ 
+ 
+ Local<Value> Script::Run() {
++    return Run(Handle<Object>());
++}
++
++Local<Value> Script::Run(Handle<Object> qml) {
+   i::Isolate* isolate = i::Isolate::Current();
+   ON_BAILOUT(isolate, "v8::Script::Run()", return Local<Value>());
+   LOG_API(isolate, "Script::Run");
+@@ -1614,10 +1623,11 @@ Local<Value> Script::Run() {
+       fun = i::Handle<i::JSFunction>(i::JSFunction::cast(*obj), isolate);
+     }
+     EXCEPTION_PREAMBLE(isolate);
++    i::Handle<i::Object> qmlglobal = Utils::OpenHandle(*qml);
+     i::Handle<i::Object> receiver(
+         isolate->context()->global_proxy(), isolate);
+     i::Handle<i::Object> result =
+-        i::Execution::Call(fun, receiver, 0, NULL, &has_pending_exception);
++        i::Execution::Call(fun, receiver, 0, NULL, &has_pending_exception, false, qmlglobal);
+     EXCEPTION_BAILOUT_CHECK(isolate, Local<Value>());
+     raw_result = *result;
+   }
+@@ -4328,6 +4338,30 @@ v8::Local<v8::Context> Context::GetCalling() {
+ }
+ 
+ 
++v8::Local<v8::Object> Context::GetCallingQmlGlobal() {
++  i::Isolate* isolate = i::Isolate::Current();
++  if (IsDeadCheck(isolate, "v8::Context::GetCallingQmlGlobal()")) {
++    return Local<Object>();
++  }
++
++  i::Context *context = isolate->context();
++  if (!context->qml_global()->IsUndefined()) {
++    i::Handle<i::Object> qmlglobal(context->qml_global());
++    return Utils::ToLocal(i::Handle<i::JSObject>::cast(qmlglobal));
++  }
++
++  i::JavaScriptFrameIterator it;
++  if (it.done()) return Local<Object>();
++  context = i::Context::cast(it.frame()->context());
++  if (!context->qml_global()->IsUndefined()) {
++    i::Handle<i::Object> qmlglobal(context->qml_global());
++    return Utils::ToLocal(i::Handle<i::JSObject>::cast(qmlglobal));
++  } else {
++      return Local<Object>();
++  }
++}
++
++
+ v8::Local<v8::Object> Context::Global() {
+   if (IsDeadCheck(i::Isolate::Current(), "v8::Context::Global()")) {
+     return Local<v8::Object>();
+diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
+index 17dfbd7..00ac676 100644
+--- a/src/arm/code-stubs-arm.cc
++++ b/src/arm/code-stubs-arm.cc
+@@ -172,6 +172,10 @@ void FastNewContextStub::Generate(MacroAssembler* masm) {
+   __ ldr(r1, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+   __ str(r1, MemOperand(r0, Context::SlotOffset(Context::GLOBAL_INDEX)));
+ 
++  // Copy the qml global object from the surrounding context.
++  __ ldr(r1, MemOperand(cp, Context::SlotOffset(Context::QML_GLOBAL_INDEX)));
++  __ str(r1, MemOperand(r0, Context::SlotOffset(Context::QML_GLOBAL_INDEX)));
++
+   // Initialize the rest of the slots to undefined.
+   __ LoadRoot(r1, Heap::kUndefinedValueRootIndex);
+   for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
+index 2ee1594..a1841f2 100644
+--- a/src/arm/full-codegen-arm.cc
++++ b/src/arm/full-codegen-arm.cc
+@@ -182,12 +182,13 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment cmnt(masm_, "[ Allocate local context");
+     // Argument to NewContext is the function, which is in r1.
+     __ push(r1);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -1168,9 +1169,9 @@ void FullCodeGenerator::EmitLoadGlobalCheckExtensions(Variable* var,
+     __ bind(&fast);
+   }
+ 
+-  __ ldr(r0, GlobalObjectOperand());
++  __ ldr(r0, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+   __ mov(r2, Operand(var->name()));
+-  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF)
++  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF || var->is_qml_global())
+       ? RelocInfo::CODE_TARGET
+       : RelocInfo::CODE_TARGET_CONTEXT;
+   Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+@@ -1246,10 +1247,10 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy) {
+       Comment cmnt(masm_, "Global variable");
+       // Use inline caching. Variable name is passed in r2 and the global
+       // object (receiver) in r0.
+-      __ ldr(r0, GlobalObjectOperand());
++      __ ldr(r0, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+       __ mov(r2, Operand(var->name()));
+       Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+-      __ Call(ic, RelocInfo::CODE_TARGET_CONTEXT);
++      __ Call(ic, var->is_qml_global()?RelocInfo::CODE_TARGET:RelocInfo::CODE_TARGET_CONTEXT);
+       context()->Plug(r0);
+       break;
+     }
+@@ -1840,7 +1841,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var,
+   if (var->IsUnallocated()) {
+     // Global var, const, or let.
+     __ mov(r2, Operand(var->name()));
+-    __ ldr(r1, GlobalObjectOperand());
++    __ ldr(r1, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+     Handle<Code> ic = is_strict_mode()
+         ? isolate()->builtins()->StoreIC_Initialize_Strict()
+         : isolate()->builtins()->StoreIC_Initialize();
+@@ -2141,10 +2142,13 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(ResolveEvalFlag flag,
+   }
+   __ mov(r1, Operand(Smi::FromInt(strict_mode)));
+   __ push(r1);
++  // Push the qml mode flag.
++  __ mov(r1, Operand(Smi::FromInt(is_qml_mode())));
++  __ push(r1);
+ 
+   __ CallRuntime(flag == SKIP_CONTEXT_LOOKUP
+                  ? Runtime::kResolvePossiblyDirectEvalNoLookup
+-                 : Runtime::kResolvePossiblyDirectEval, 4);
++                 : Runtime::kResolvePossiblyDirectEval, 5);
+ }
+ 
+ 
+@@ -2217,9 +2221,9 @@ void FullCodeGenerator::VisitCall(Call* expr) {
+     context()->DropAndPlug(1, r0);
+   } else if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     // Push global object as receiver for the call IC.
+-    __ ldr(r0, GlobalObjectOperand());
++    __ ldr(r0, proxy->var()->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+     __ push(r0);
+-    EmitCallWithIC(expr, proxy->name(), RelocInfo::CODE_TARGET_CONTEXT);
++    EmitCallWithIC(expr, proxy->name(), proxy->var()->is_qml_global()?RelocInfo::CODE_TARGET:RelocInfo::CODE_TARGET_CONTEXT);
+   } else if (proxy != NULL && proxy->var()->IsLookupSlot()) {
+     // Call to a lookup slot (dynamically introduced variable).
+     Label slow, done;
+@@ -3630,7 +3634,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
+         // but "delete this" is allowed.
+         ASSERT(strict_mode_flag() == kNonStrictMode || var->is_this());
+         if (var->IsUnallocated()) {
+-          __ ldr(r2, GlobalObjectOperand());
++          __ ldr(r2, var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+           __ mov(r1, Operand(var->name()));
+           __ mov(r0, Operand(Smi::FromInt(kNonStrictMode)));
+           __ Push(r2, r1, r0);
+@@ -3916,7 +3920,7 @@ void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
+   VariableProxy* proxy = expr->AsVariableProxy();
+   if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     Comment cmnt(masm_, "Global variable");
+-    __ ldr(r0, GlobalObjectOperand());
++    __ ldr(r0, proxy->var()->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+     __ mov(r2, Operand(proxy->name()));
+     Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+     // Use a regular load, not a contextual load, to avoid a reference
+diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
+index 8495939..00582ea 100644
+--- a/src/arm/lithium-arm.cc
++++ b/src/arm/lithium-arm.cc
+@@ -1122,7 +1122,7 @@ LInstruction* LChunkBuilder::DoOuterContext(HOuterContext* instr) {
+ 
+ LInstruction* LChunkBuilder::DoGlobalObject(HGlobalObject* instr) {
+   LOperand* context = UseRegisterAtStart(instr->value());
+-  return DefineAsRegister(new LGlobalObject(context));
++  return DefineAsRegister(new LGlobalObject(context, instr->qml_global()));
+ }
+ 
+ 
+diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
+index 73c7e45..49cdccc 100644
+--- a/src/arm/lithium-arm.h
++++ b/src/arm/lithium-arm.h
+@@ -1301,13 +1301,17 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+ 
+ class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
+  public:
+-  explicit LGlobalObject(LOperand* context) {
++  explicit LGlobalObject(LOperand* context, bool qml_global) {
+     inputs_[0] = context;
++    qml_global_ = qml_global;
+   }
+ 
+   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global-object")
+ 
+   LOperand* context() { return InputAt(0); }
++  bool qml_global() { return qml_global_; }
++ private:
++  bool qml_global_;
+ };
+ 
+ 
+diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
+index f6750a2..63c8463 100644
+--- a/src/arm/lithium-codegen-arm.cc
++++ b/src/arm/lithium-codegen-arm.cc
+@@ -190,12 +190,13 @@ bool LCodeGen::GeneratePrologue() {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment(";;; Allocate local context");
+     // Argument to NewContext is the function, which is in r1.
+     __ push(r1);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -2798,7 +2799,7 @@ void LCodeGen::DoOuterContext(LOuterContext* instr) {
+ 
+ void LCodeGen::DoGlobalObject(LGlobalObject* instr) {
+   Register result = ToRegister(instr->result());
+-  __ ldr(result, ContextOperand(cp, Context::GLOBAL_INDEX));
++  __ ldr(result, ContextOperand(cp, instr->qml_global()?Context::QML_GLOBAL_INDEX:Context::GLOBAL_INDEX));
+ }
+ 
+ 
+diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
+index d42ccec..9adeb36 100644
+--- a/src/arm/macro-assembler-arm.h
++++ b/src/arm/macro-assembler-arm.h
+@@ -1260,6 +1260,11 @@ static inline MemOperand GlobalObjectOperand()  {
+ }
+ 
+ 
++static inline MemOperand QmlGlobalObjectOperand()  {
++  return ContextOperand(cp, Context::QML_GLOBAL_INDEX);
++}
++
++
+ #ifdef GENERATED_CODE_COVERAGE
+ #define CODE_COVERAGE_STRINGIFY(x) #x
+ #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
+diff --git a/src/ast-inl.h b/src/ast-inl.h
+index 731ad2f..15702cf 100644
+--- a/src/ast-inl.h
++++ b/src/ast-inl.h
+@@ -116,6 +116,11 @@ bool FunctionLiteral::strict_mode() const {
+ }
+ 
+ 
++bool FunctionLiteral::qml_mode() const {
++  return scope()->is_qml_mode();
++}
++
++
+ } }  // namespace v8::internal
+ 
+ #endif  // V8_AST_INL_H_
+diff --git a/src/ast.h b/src/ast.h
+index 00cfd7f..319d090 100644
+--- a/src/ast.h
++++ b/src/ast.h
+@@ -1658,6 +1658,7 @@ class FunctionLiteral: public Expression {
+   bool is_expression() const { return is_expression_; }
+   bool is_anonymous() const { return is_anonymous_; }
+   bool strict_mode() const;
++  bool qml_mode() const;
+ 
+   int materialized_literal_count() { return materialized_literal_count_; }
+   int expected_property_count() { return expected_property_count_; }
+diff --git a/src/code-stubs.h b/src/code-stubs.h
+index 9d4baf4..b7cac89 100644
+--- a/src/code-stubs.h
++++ b/src/code-stubs.h
+@@ -323,7 +323,7 @@ class FastNewContextStub : public CodeStub {
+   static const int kMaximumSlots = 64;
+ 
+   explicit FastNewContextStub(int slots) : slots_(slots) {
+-    ASSERT(slots_ > 0 && slots <= kMaximumSlots);
++    ASSERT(slots_ >= 0 && slots <= kMaximumSlots);
+   }
+ 
+   void Generate(MacroAssembler* masm);
+diff --git a/src/compiler.cc b/src/compiler.cc
+index 5a86b4e..596df4a 100644
+--- a/src/compiler.cc
++++ b/src/compiler.cc
+@@ -450,7 +450,8 @@ Handle<SharedFunctionInfo> Compiler::Compile(Handle<String> source,
+                                              v8::Extension* extension,
+                                              ScriptDataImpl* input_pre_data,
+                                              Handle<Object> script_data,
+-                                             NativesFlag natives) {
++                                             NativesFlag natives,
++                                             v8::Script::CompileFlags compile_flags) {
+   Isolate* isolate = source->GetIsolate();
+   int source_length = source->length();
+   isolate->counters()->total_load_size()->Increment(source_length);
+@@ -517,6 +518,7 @@ Handle<SharedFunctionInfo> Compiler::Compile(Handle<String> source,
+     info.MarkAsGlobal();
+     info.SetExtension(extension);
+     info.SetPreParseData(pre_data);
++    if (compile_flags & v8::Script::QmlMode) info.MarkAsQmlMode();
+     if (natives == NATIVES_CODE) {
+       info.MarkAsAllowingNativesSyntax();
+     }
+@@ -539,7 +541,8 @@ Handle<SharedFunctionInfo> Compiler::Compile(Handle<String> source,
+ Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,
+                                                  Handle<Context> context,
+                                                  bool is_global,
+-                                                 StrictModeFlag strict_mode) {
++                                                 StrictModeFlag strict_mode,
++                                                 bool qml_mode) {
+   Isolate* isolate = source->GetIsolate();
+   int source_length = source->length();
+   isolate->counters()->total_eval_size()->Increment(source_length);
+@@ -563,6 +566,7 @@ Handle<SharedFunctionInfo> Compiler::CompileEval(Handle<String> source,
+     CompilationInfo info(script);
+     info.MarkAsEval();
+     if (is_global) info.MarkAsGlobal();
++    if (qml_mode) info.MarkAsQmlMode();
+     if (strict_mode == kStrictMode) info.MarkAsStrictMode();
+     info.SetCallingContext(context);
+     result = MakeFunctionInfo(&info);
+@@ -607,6 +611,12 @@ bool Compiler::CompileLazy(CompilationInfo* info) {
+       info->MarkAsStrictMode();
+     }
+ 
++    // After parsing we know function's qml mode. Remember it.
++    if (info->function()->qml_mode()) {
++      shared->set_qml_mode(true);
++      info->MarkAsQmlMode();
++    }
++
+     // Compile the code.
+     if (!MakeCode(info)) {
+       if (!isolate->has_pending_exception()) {
+@@ -752,6 +762,7 @@ void Compiler::SetFunctionInfo(Handle<SharedFunctionInfo> function_info,
+       *lit->this_property_assignments());
+   function_info->set_allows_lazy_compilation(lit->AllowsLazyCompilation());
+   function_info->set_strict_mode(lit->strict_mode());
++  function_info->set_qml_mode(lit->qml_mode());
+   function_info->set_uses_arguments(lit->scope()->arguments() != NULL);
+   function_info->set_has_duplicate_parameters(lit->has_duplicate_parameters());
+ }
+diff --git a/src/compiler.h b/src/compiler.h
+index 09aa23d..8eacb71 100644
+--- a/src/compiler.h
++++ b/src/compiler.h
+@@ -54,6 +54,7 @@ class CompilationInfo BASE_EMBEDDED {
+   bool is_global() const { return IsGlobal::decode(flags_); }
+   bool is_strict_mode() const { return IsStrictMode::decode(flags_); }
+   bool is_in_loop() const { return IsInLoop::decode(flags_); }
++  bool is_qml_mode() const { return IsQmlMode::decode(flags_); }
+   FunctionLiteral* function() const { return function_; }
+   Scope* scope() const { return scope_; }
+   Handle<Code> code() const { return code_; }
+@@ -83,6 +84,9 @@ class CompilationInfo BASE_EMBEDDED {
+     ASSERT(is_lazy());
+     flags_ |= IsInLoop::encode(true);
+   }
++  void MarkAsQmlMode() {
++    flags_ |= IsQmlMode::encode(true);
++  }
+   void MarkAsAllowingNativesSyntax() {
+     flags_ |= IsNativesSyntaxAllowed::encode(true);
+   }
+@@ -180,6 +184,9 @@ class CompilationInfo BASE_EMBEDDED {
+     if (!shared_info_.is_null() && shared_info_->strict_mode()) {
+       MarkAsStrictMode();
+     }
++    if (!shared_info_.is_null() && shared_info_->qml_mode()) {
++      MarkAsQmlMode();
++    }
+   }
+ 
+   void SetMode(Mode mode) {
+@@ -203,7 +210,8 @@ class CompilationInfo BASE_EMBEDDED {
+   class IsNativesSyntaxAllowed: public BitField<bool, 5, 1> {};
+   // Is this a function from our natives.
+   class IsNative: public BitField<bool, 6, 1> {};
+-
++  // Qml mode
++  class IsQmlMode: public BitField<bool, 7, 1> {};
+ 
+   unsigned flags_;
+ 
+@@ -269,13 +277,15 @@ class Compiler : public AllStatic {
+                                             v8::Extension* extension,
+                                             ScriptDataImpl* pre_data,
+                                             Handle<Object> script_data,
+-                                            NativesFlag is_natives_code);
++                                            NativesFlag is_natives_code,
++                                            v8::Script::CompileFlags = v8::Script::Default);
+ 
+   // Compile a String source within a context for Eval.
+   static Handle<SharedFunctionInfo> CompileEval(Handle<String> source,
+                                                 Handle<Context> context,
+                                                 bool is_global,
+-                                                StrictModeFlag strict_mode);
++                                                StrictModeFlag strict_mode,
++                                                bool qml_mode);
+ 
+   // Compile from function info (used for lazy compilation). Returns true on
+   // success and false if the compilation resulted in a stack overflow.
+diff --git a/src/contexts.cc b/src/contexts.cc
+index 007d30d..825493a 100644
+--- a/src/contexts.cc
++++ b/src/contexts.cc
+@@ -103,6 +103,9 @@ Handle<Object> Context::Lookup(Handle<String> name,
+     PrintF(")\n");
+   }
+ 
++  Handle<JSObject> qml_global;
++  Handle<JSObject> qml_global_global;
++
+   do {
+     if (FLAG_trace_contexts) {
+       PrintF(" - looking in context %p", reinterpret_cast<void*>(*context));
+@@ -110,6 +113,11 @@ Handle<Object> Context::Lookup(Handle<String> name,
+       PrintF("\n");
+     }
+ 
++    if (qml_global.is_null() && !context->qml_global()->IsUndefined()) {
++      qml_global = Handle<JSObject>(context->qml_global(), isolate);
++      qml_global_global = Handle<JSObject>(context->global(), isolate);
++    }
++
+     // 1. Check global objects, subjects of with, and extension objects.
+     if (context->IsGlobalContext() ||
+         context->IsWithContext() ||
+@@ -221,6 +229,33 @@ Handle<Object> Context::Lookup(Handle<String> name,
+     }
+   } while (follow_context_chain);
+ 
++  if (!qml_global.is_null()) {
++    if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0) {
++      *attributes = qml_global_global->GetLocalPropertyAttribute(*name);
++    } else {
++      *attributes = qml_global_global->GetPropertyAttribute(*name);
++    }
++
++    if (*attributes != ABSENT) {
++      *attributes = ABSENT;
++    } else {
++      if ((flags & FOLLOW_PROTOTYPE_CHAIN) == 0) {
++        *attributes = qml_global->GetLocalPropertyAttribute(*name);
++      } else {
++        *attributes = qml_global->GetPropertyAttribute(*name);
++      }
++
++      if (*attributes != ABSENT) {
++        // property found
++        if (FLAG_trace_contexts) {
++          PrintF("=> found property in qml global object %p\n",
++                 reinterpret_cast<void*>(*qml_global));
++        }
++        return qml_global;
++      }
++    }
++  }
++
+   if (FLAG_trace_contexts) {
+     PrintF("=> no property/slot found\n");
+   }
+diff --git a/src/contexts.h b/src/contexts.h
+index b80475f..28ba69e 100644
+--- a/src/contexts.h
++++ b/src/contexts.h
+@@ -196,6 +196,7 @@ class Context: public FixedArray {
+     // contexts), eval extension object (function contexts), subject of with
+     // (with contexts), or the variable name (catch contexts).
+     EXTENSION_INDEX,
++    QML_GLOBAL_INDEX,
+     GLOBAL_INDEX,
+     MIN_CONTEXT_SLOTS,
+ 
+@@ -297,6 +298,9 @@ class Context: public FixedArray {
+   }
+   void set_global(GlobalObject* global) { set(GLOBAL_INDEX, global); }
+ 
++  JSObject *qml_global() { return reinterpret_cast<JSObject *>(get(QML_GLOBAL_INDEX)); }
++  void set_qml_global(JSObject *qml_global) { set(QML_GLOBAL_INDEX, qml_global); }
++
+   // Returns a JSGlobalProxy object or null.
+   JSObject* global_proxy();
+   void set_global_proxy(JSObject* global);
+diff --git a/src/execution.cc b/src/execution.cc
+index 2021c0f..c64c9ea 100644
+--- a/src/execution.cc
++++ b/src/execution.cc
+@@ -71,7 +71,8 @@ static Handle<Object> Invoke(bool construct,
+                              Handle<Object> receiver,
+                              int argc,
+                              Object*** args,
+-                             bool* has_pending_exception) {
++                             bool* has_pending_exception,
++                             Handle<Object> qml) {
+   Isolate* isolate = func->GetIsolate();
+ 
+   // Entering JavaScript.
+@@ -106,6 +107,12 @@ static Handle<Object> Invoke(bool construct,
+   // make the current one is indeed a global object.
+   ASSERT(func->context()->global()->IsGlobalObject());
+ 
++  Handle<JSObject> oldqml;
++  if (!qml.is_null()) {
++    oldqml = Handle<JSObject>(func->context()->qml_global());
++    func->context()->set_qml_global(JSObject::cast(*qml));
++  }
++
+   {
+     // Save and restore context around invocation and block the
+     // allocation of handles without explicit handle scopes.
+@@ -121,6 +128,9 @@ static Handle<Object> Invoke(bool construct,
+                                 receiver_pointer, argc, args);
+   }
+ 
++  if (!qml.is_null()) 
++    func->context()->set_qml_global(*oldqml);
++
+ #ifdef DEBUG
+   value->Verify();
+ #endif
+@@ -149,7 +159,18 @@ Handle<Object> Execution::Call(Handle<Object> callable,
+                                int argc,
+                                Object*** args,
+                                bool* pending_exception,
+-                               bool convert_receiver) {
++                               bool convert_receiver)
++{
++    return Call(callable, receiver, argc, args, pending_exception, convert_receiver, Handle<Object>());
++}
++
++Handle<Object> Execution::Call(Handle<Object> callable,
++                               Handle<Object> receiver,
++                               int argc,
++                               Object*** args,
++                               bool* pending_exception,
++                               bool convert_receiver,
++                               Handle<Object> qml) {
+   *pending_exception = false;
+ 
+   if (!callable->IsJSFunction()) {
+@@ -173,14 +194,14 @@ Handle<Object> Execution::Call(Handle<Object> callable,
+     if (*pending_exception) return callable;
+   }
+ 
+-  return Invoke(false, func, receiver, argc, args, pending_exception);
++  return Invoke(false, func, receiver, argc, args, pending_exception, qml);
+ }
+ 
+ 
+ Handle<Object> Execution::New(Handle<JSFunction> func, int argc,
+                               Object*** args, bool* pending_exception) {
+   return Invoke(true, func, Isolate::Current()->global(), argc, args,
+-                pending_exception);
++                pending_exception, Handle<Object>());
+ }
+ 
+ 
+@@ -199,7 +220,7 @@ Handle<Object> Execution::TryCall(Handle<JSFunction> func,
+   *caught_exception = false;
+ 
+   Handle<Object> result = Invoke(false, func, receiver, argc, args,
+-                                 caught_exception);
++                                 caught_exception, Handle<Object>());
+ 
+   if (*caught_exception) {
+     ASSERT(catcher.HasCaught());
+diff --git a/src/execution.h b/src/execution.h
+index 9fa6e78..baa58b5 100644
+--- a/src/execution.h
++++ b/src/execution.h
+@@ -65,6 +65,14 @@ class Execution : public AllStatic {
+                              bool* pending_exception,
+                              bool convert_receiver = false);
+ 
++  static Handle<Object> Call(Handle<Object> callable,
++                             Handle<Object> receiver,
++                             int argc,
++                             Object*** args,
++                             bool* pending_exception,
++                             bool convert_receiver,
++                             Handle<Object> qml);
++
+   // Construct object from function, the caller supplies an array of
+   // arguments. Arguments are Object* type. After function returns,
+   // pointers in 'args' might be invalid.
+diff --git a/src/full-codegen.cc b/src/full-codegen.cc
+index e822588..516d237 100644
+--- a/src/full-codegen.cc
++++ b/src/full-codegen.cc
+@@ -512,7 +512,7 @@ void FullCodeGenerator::VisitDeclarations(
+   // Batch declare global functions and variables.
+   if (global_count > 0) {
+     Handle<FixedArray> array =
+-        isolate()->factory()->NewFixedArray(2 * global_count, TENURED);
++        isolate()->factory()->NewFixedArray(3 * global_count, TENURED);
+     for (int j = 0, i = 0; i < length; i++) {
+       Declaration* decl = declarations->at(i);
+       Variable* var = decl->proxy()->var();
+@@ -536,6 +536,7 @@ void FullCodeGenerator::VisitDeclarations(
+           }
+           array->set(j++, *function);
+         }
++        array->set(j++, Smi::FromInt(var->is_qml_global()));
+       }
+     }
+     // Invoke the platform-dependent code generator to do the actual
+diff --git a/src/full-codegen.h b/src/full-codegen.h
+index 6958dae..48753c5 100644
+--- a/src/full-codegen.h
++++ b/src/full-codegen.h
+@@ -581,6 +581,7 @@ class FullCodeGenerator: public AstVisitor {
+   StrictModeFlag strict_mode_flag() {
+     return is_strict_mode() ? kStrictMode : kNonStrictMode;
+   }
++  bool is_qml_mode() { return function()->qml_mode(); }
+   FunctionLiteral* function() { return info_->function(); }
+   Scope* scope() { return scope_; }
+ 
+diff --git a/src/heap.cc b/src/heap.cc
+index c730455..447dce1 100644
+--- a/src/heap.cc
++++ b/src/heap.cc
+@@ -4407,6 +4407,7 @@ MaybeObject* Heap::AllocateFunctionContext(int length, JSFunction* function) {
+   context->set_previous(function->context());
+   context->set_extension(NULL);
+   context->set_global(function->context()->global());
++  context->set_qml_global(function->context()->qml_global());
+   return context;
+ }
+ 
+@@ -4427,6 +4428,7 @@ MaybeObject* Heap::AllocateCatchContext(JSFunction* function,
+   context->set_previous(previous);
+   context->set_extension(name);
+   context->set_global(previous->global());
++  context->set_qml_global(previous->qml_global());
+   context->set(Context::THROWN_OBJECT_INDEX, thrown_object);
+   return context;
+ }
+@@ -4445,6 +4447,7 @@ MaybeObject* Heap::AllocateWithContext(JSFunction* function,
+   context->set_previous(previous);
+   context->set_extension(extension);
+   context->set_global(previous->global());
++  context->set_qml_global(previous->qml_global());
+   return context;
+ }
+ 
+@@ -4463,6 +4466,7 @@ MaybeObject* Heap::AllocateBlockContext(JSFunction* function,
+   context->set_previous(previous);
+   context->set_extension(scope_info);
+   context->set_global(previous->global());
++  context->set_qml_global(previous->qml_global());
+   return context;
+ }
+ 
+diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
+index 6b43f53..d0e6fb0 100644
+--- a/src/hydrogen-instructions.h
++++ b/src/hydrogen-instructions.h
+@@ -1394,7 +1394,7 @@ class HOuterContext: public HUnaryOperation {
+ 
+ class HGlobalObject: public HUnaryOperation {
+  public:
+-  explicit HGlobalObject(HValue* context) : HUnaryOperation(context) {
++  explicit HGlobalObject(HValue* context) : HUnaryOperation(context), qml_global_(false) {
+     set_representation(Representation::Tagged());
+     SetFlag(kUseGVN);
+   }
+@@ -1405,8 +1405,14 @@ class HGlobalObject: public HUnaryOperation {
+     return Representation::Tagged();
+   }
+ 
++  bool qml_global() { return qml_global_; }
++  void set_qml_global(bool v) { qml_global_ = v; }
++
+  protected:
+   virtual bool DataEquals(HValue* other) { return true; }
++
++ private:
++  bool qml_global_;
+ };
+ 
+ 
+diff --git a/src/hydrogen.cc b/src/hydrogen.cc
+index 64a6ae5..f0c1763 100644
+--- a/src/hydrogen.cc
++++ b/src/hydrogen.cc
+@@ -3174,6 +3174,7 @@ void HGraphBuilder::VisitVariableProxy(VariableProxy* expr) {
+       } else {
+         HValue* context = environment()->LookupContext();
+         HGlobalObject* global_object = new(zone()) HGlobalObject(context);
++        if (variable->is_qml_global()) global_object->set_qml_global(true);
+         AddInstruction(global_object);
+         HLoadGlobalGeneric* instr =
+             new(zone()) HLoadGlobalGeneric(context,
+@@ -3640,6 +3641,7 @@ void HGraphBuilder::HandleGlobalVariableAssignment(Variable* var,
+   } else {
+     HValue* context =  environment()->LookupContext();
+     HGlobalObject* global_object = new(zone()) HGlobalObject(context);
++    if (var->is_qml_global()) global_object->set_qml_global(true);
+     AddInstruction(global_object);
+     HStoreGlobalGeneric* instr =
+         new(zone()) HStoreGlobalGeneric(context,
+diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
+index 1ca577c..6cc80d3 100644
+--- a/src/ia32/code-stubs-ia32.cc
++++ b/src/ia32/code-stubs-ia32.cc
+@@ -143,6 +143,11 @@ void FastNewContextStub::Generate(MacroAssembler* masm) {
+   __ mov(ebx, Operand(esi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+   __ mov(Operand(eax, Context::SlotOffset(Context::GLOBAL_INDEX)), ebx);
+ 
++  // Copy the qml global object from the previous context.
++  __ mov(ebx, Operand(esi, Context::SlotOffset(Context::QML_GLOBAL_INDEX)));
++  __ mov(Operand(eax, Context::SlotOffset(Context::QML_GLOBAL_INDEX)), ebx);
++
++
+   // Initialize the rest of the slots to undefined.
+   __ mov(ebx, factory->undefined_value());
+   for (int i = Context::MIN_CONTEXT_SLOTS; i < length; i++) {
+diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
+index d45a9cd..a5883a2 100644
+--- a/src/ia32/full-codegen-ia32.cc
++++ b/src/ia32/full-codegen-ia32.cc
+@@ -178,12 +178,13 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment cmnt(masm_, "[ Allocate local context");
+     // Argument to NewContext is the function, which is still in edi.
+     __ push(edi);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -1152,10 +1153,10 @@ void FullCodeGenerator::EmitLoadGlobalCheckExtensions(Variable* var,
+ 
+   // All extension objects were empty and it is safe to use a global
+   // load IC call.
+-  __ mov(eax, GlobalObjectOperand());
++  __ mov(eax, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+   __ mov(ecx, var->name());
+   Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+-  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF)
++  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF || var->is_qml_global())
+       ? RelocInfo::CODE_TARGET
+       : RelocInfo::CODE_TARGET_CONTEXT;
+   __ call(ic, mode);
+@@ -1229,10 +1230,10 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy) {
+       Comment cmnt(masm_, "Global variable");
+       // Use inline caching. Variable name is passed in ecx and the global
+       // object in eax.
+-      __ mov(eax, GlobalObjectOperand());
++      __ mov(eax, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+       __ mov(ecx, var->name());
+       Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+-      __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
++      __ call(ic, var->is_qml_global()?RelocInfo::CODE_TARGET:RelocInfo::CODE_TARGET_CONTEXT);
+       context()->Plug(eax);
+       break;
+     }
+@@ -1833,7 +1834,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var,
+   if (var->IsUnallocated()) {
+     // Global var, const, or let.
+     __ mov(ecx, var->name());
+-    __ mov(edx, GlobalObjectOperand());
++    __ mov(edx, var->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+     Handle<Code> ic = is_strict_mode()
+         ? isolate()->builtins()->StoreIC_Initialize_Strict()
+         : isolate()->builtins()->StoreIC_Initialize();
+@@ -2147,9 +2148,12 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(ResolveEvalFlag flag,
+   }
+   __ push(Immediate(Smi::FromInt(strict_mode)));
+ 
++  // Push the qml mode flag
++  __ push(Immediate(Smi::FromInt(is_qml_mode())));
++
+   __ CallRuntime(flag == SKIP_CONTEXT_LOOKUP
+                  ? Runtime::kResolvePossiblyDirectEvalNoLookup
+-                 : Runtime::kResolvePossiblyDirectEval, 4);
++                 : Runtime::kResolvePossiblyDirectEval, 5);
+ }
+ 
+ 
+@@ -2220,9 +2224,9 @@ void FullCodeGenerator::VisitCall(Call* expr) {
+ 
+   } else if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     // Push global object as receiver for the call IC.
+-    __ push(GlobalObjectOperand());
++    __ push(proxy->var()->is_qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+     increment_stack_height();
+-    EmitCallWithIC(expr, proxy->name(), RelocInfo::CODE_TARGET_CONTEXT);
++    EmitCallWithIC(expr, proxy->name(), proxy->var()->is_qml_global()?RelocInfo::CODE_TARGET:RelocInfo::CODE_TARGET_CONTEXT);
+ 
+   } else if (proxy != NULL && proxy->var()->IsLookupSlot()) {
+     // Call to a lookup slot (dynamically introduced variable).
+@@ -3688,7 +3692,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
+         // but "delete this" is allowed.
+         ASSERT(strict_mode_flag() == kNonStrictMode || var->is_this());
+         if (var->IsUnallocated()) {
+-          __ push(GlobalObjectOperand());
++          __ push(var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+           __ push(Immediate(var->name()));
+           __ push(Immediate(Smi::FromInt(kNonStrictMode)));
+           __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
+@@ -3996,7 +4000,7 @@ void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
+ 
+   if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     Comment cmnt(masm_, "Global variable");
+-    __ mov(eax, GlobalObjectOperand());
++    __ mov(eax, proxy->var()->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+     __ mov(ecx, Immediate(proxy->name()));
+     Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+     // Use a regular load, not a contextual load, to avoid a reference
+diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
+index 9e1fd34..1abcdd3 100644
+--- a/src/ia32/lithium-codegen-ia32.cc
++++ b/src/ia32/lithium-codegen-ia32.cc
+@@ -211,12 +211,13 @@ bool LCodeGen::GeneratePrologue() {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment(";;; Allocate local context");
+     // Argument to NewContext is the function, which is still in edi.
+     __ push(edi);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -2635,7 +2636,7 @@ void LCodeGen::DoOuterContext(LOuterContext* instr) {
+ void LCodeGen::DoGlobalObject(LGlobalObject* instr) {
+   Register context = ToRegister(instr->context());
+   Register result = ToRegister(instr->result());
+-  __ mov(result, Operand(context, Context::SlotOffset(Context::GLOBAL_INDEX)));
++  __ mov(result, Operand(context, Context::SlotOffset(instr->qml_global()?Context::QML_GLOBAL_INDEX:Context::GLOBAL_INDEX)));
+ }
+ 
+ 
+diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
+index 856106c..0b058e6 100644
+--- a/src/ia32/lithium-ia32.cc
++++ b/src/ia32/lithium-ia32.cc
+@@ -1138,7 +1138,7 @@ LInstruction* LChunkBuilder::DoOuterContext(HOuterContext* instr) {
+ 
+ LInstruction* LChunkBuilder::DoGlobalObject(HGlobalObject* instr) {
+   LOperand* context = UseRegisterAtStart(instr->value());
+-  return DefineAsRegister(new LGlobalObject(context));
++  return DefineAsRegister(new LGlobalObject(context, instr->qml_global()));
+ }
+ 
+ 
+diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
+index 3a06ac3..087d5cb 100644
+--- a/src/ia32/lithium-ia32.h
++++ b/src/ia32/lithium-ia32.h
+@@ -1336,13 +1336,17 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+ 
+ class LGlobalObject: public LTemplateInstruction<1, 1, 0> {
+  public:
+-  explicit LGlobalObject(LOperand* context) {
++  explicit LGlobalObject(LOperand* context, bool qml_global) {
+     inputs_[0] = context;
++    qml_global_ = qml_global;
+   }
+ 
+   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global-object")
+ 
+   LOperand* context() { return InputAt(0); }
++  bool qml_global() { return qml_global_; }
++ private:
++  bool qml_global_;
+ };
+ 
+ 
+diff --git a/src/ia32/macro-assembler-ia32.h b/src/ia32/macro-assembler-ia32.h
+index a1b42c2..7a64b9a 100644
+--- a/src/ia32/macro-assembler-ia32.h
++++ b/src/ia32/macro-assembler-ia32.h
+@@ -931,6 +931,9 @@ static inline Operand GlobalObjectOperand() {
+   return ContextOperand(esi, Context::GLOBAL_INDEX);
+ }
+ 
++static inline Operand QmlGlobalObjectOperand() {
++  return ContextOperand(esi, Context::QML_GLOBAL_INDEX);
++}
+ 
+ // Generates an Operand for saving parameters after PrepareCallApiFunction.
+ Operand ApiParameterOperand(int index);
+diff --git a/src/objects-inl.h b/src/objects-inl.h
+index 36af868..375df0f 100644
+--- a/src/objects-inl.h
++++ b/src/objects-inl.h
+@@ -3615,6 +3615,8 @@ void SharedFunctionInfo::set_optimization_disabled(bool disable) {
+ 
+ BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, strict_mode,
+                kStrictModeFunction)
++BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, qml_mode,
++               kQmlModeFunction)
+ BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, native, kNative)
+ BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints,
+                name_should_print_as_anonymous,
+diff --git a/src/objects.h b/src/objects.h
+index dea5bbd..71895be 100644
+--- a/src/objects.h
++++ b/src/objects.h
+@@ -4725,6 +4725,9 @@ class SharedFunctionInfo: public HeapObject {
+   // Indicates whether the function is a strict mode function.
+   DECL_BOOLEAN_ACCESSORS(strict_mode)
+ 
++  // Indicates whether the function is a qml mode function.
++  DECL_BOOLEAN_ACCESSORS(qml_mode)
++
+   // False if the function definitely does not allocate an arguments object.
+   DECL_BOOLEAN_ACCESSORS(uses_arguments)
+ 
+@@ -4939,6 +4942,7 @@ class SharedFunctionInfo: public HeapObject {
+     kCodeAgeShift,
+     kOptimizationDisabled = kCodeAgeShift + kCodeAgeSize,
+     kStrictModeFunction,
++    kQmlModeFunction,
+     kUsesArguments,
+     kHasDuplicateParameters,
+     kNative,
+diff --git a/src/parser.cc b/src/parser.cc
+index ad8850e..a9af8eb 100644
+--- a/src/parser.cc
++++ b/src/parser.cc
+@@ -594,7 +594,8 @@ Parser::Parser(Handle<Script> script,
+ 
+ FunctionLiteral* Parser::ParseProgram(Handle<String> source,
+                                       bool in_global_context,
+-                                      StrictModeFlag strict_mode) {
++                                      StrictModeFlag strict_mode,
++                                      bool qml_mode) {
+   ZoneScope zone_scope(isolate(), DONT_DELETE_ON_EXIT);
+ 
+   HistogramTimerScope timer(isolate()->counters()->parse());
+@@ -610,11 +611,11 @@ FunctionLiteral* Parser::ParseProgram(Handle<String> source,
+     ExternalTwoByteStringUC16CharacterStream stream(
+         Handle<ExternalTwoByteString>::cast(source), 0, source->length());
+     scanner_.Initialize(&stream);
+-    return DoParseProgram(source, in_global_context, strict_mode, &zone_scope);
++    return DoParseProgram(source, in_global_context, strict_mode, qml_mode, &zone_scope);
+   } else {
+     GenericStringUC16CharacterStream stream(source, 0, source->length());
+     scanner_.Initialize(&stream);
+-    return DoParseProgram(source, in_global_context, strict_mode, &zone_scope);
++    return DoParseProgram(source, in_global_context, strict_mode, qml_mode, &zone_scope);
+   }
+ }
+ 
+@@ -622,6 +623,7 @@ FunctionLiteral* Parser::ParseProgram(Handle<String> source,
+ FunctionLiteral* Parser::DoParseProgram(Handle<String> source,
+                                         bool in_global_context,
+                                         StrictModeFlag strict_mode,
++                                        bool qml_mode,
+                                         ZoneScope* zone_scope) {
+   ASSERT(target_stack_ == NULL);
+   if (pre_data_ != NULL) pre_data_->Initialize();
+@@ -642,6 +644,9 @@ FunctionLiteral* Parser::DoParseProgram(Handle<String> source,
+     if (strict_mode == kStrictMode) {
+       top_scope_->EnableStrictMode();
+     }
++    if (qml_mode) {
++      scope->EnableQmlMode();
++    }
+     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16);
+     bool ok = true;
+     int beg_loc = scanner().location().beg_pos;
+@@ -736,6 +741,9 @@ FunctionLiteral* Parser::ParseLazy(CompilationInfo* info,
+     if (shared_info->strict_mode()) {
+       top_scope_->EnableStrictMode();
+     }
++    if (shared_info->qml_mode()) {
++      top_scope_->EnableQmlMode();
++    }
+ 
+     FunctionLiteral::Type type = shared_info->is_expression()
+         ? (shared_info->is_anonymous()
+@@ -1806,6 +1814,11 @@ Block* Parser::ParseVariableDeclarations(VariableDeclarationContext var_context,
+         arguments->Add(value);
+         value = NULL;  // zap the value to avoid the unnecessary assignment
+ 
++        int qml_mode = 0;
++        if (top_scope_->is_qml_mode() && !Isolate::Current()->global()->HasProperty(*name)) 
++          qml_mode = 1;
++        arguments->Add(NewNumberLiteral(qml_mode));
++
+         // Construct the call to Runtime_InitializeConstGlobal
+         // and add it to the initialization statement block.
+         // Note that the function does different things depending on
+@@ -1824,6 +1837,11 @@ Block* Parser::ParseVariableDeclarations(VariableDeclarationContext var_context,
+             : kNonStrictMode;
+         arguments->Add(NewNumberLiteral(flag));
+ 
++        int qml_mode = 0;
++        if (top_scope_->is_qml_mode() && !Isolate::Current()->global()->HasProperty(*name)) 
++          qml_mode = 1;
++        arguments->Add(NewNumberLiteral(qml_mode));
++
+         // Be careful not to assign a value to the global variable if
+         // we're in a with. The initialization value should not
+         // necessarily be stored in the global object in that case,
+@@ -5217,7 +5235,8 @@ bool ParserApi::Parse(CompilationInfo* info) {
+       Handle<String> source = Handle<String>(String::cast(script->source()));
+       result = parser.ParseProgram(source,
+                                    info->is_global(),
+-                                   info->StrictMode());
++                                   info->StrictMode(),
++                                   info->is_qml_mode());
+     }
+   }
+   info->SetFunction(result);
+diff --git a/src/parser.h b/src/parser.h
+index d834ed1..d88d1ef 100644
+--- a/src/parser.h
++++ b/src/parser.h
+@@ -426,7 +426,8 @@ class Parser {
+   // Returns NULL if parsing failed.
+   FunctionLiteral* ParseProgram(Handle<String> source,
+                                 bool in_global_context,
+-                                StrictModeFlag strict_mode);
++                                StrictModeFlag strict_mode,
++                                bool qml_mode);
+ 
+   FunctionLiteral* ParseLazy(CompilationInfo* info);
+ 
+@@ -466,6 +467,7 @@ class Parser {
+   FunctionLiteral* DoParseProgram(Handle<String> source,
+                                   bool in_global_context,
+                                   StrictModeFlag strict_mode,
++                                  bool qml_mode,
+                                   ZoneScope* zone_scope);
+ 
+   // Report syntax error
+diff --git a/src/prettyprinter.cc b/src/prettyprinter.cc
+index 37c76ce..73812fd 100644
+--- a/src/prettyprinter.cc
++++ b/src/prettyprinter.cc
+@@ -618,6 +618,9 @@ void AstPrinter::PrintLiteralWithModeIndented(const char* info,
+     EmbeddedVector<char, 256> buf;
+     int pos = OS::SNPrintF(buf, "%s (mode = %s", info,
+                            Variable::Mode2String(var->mode()));
++    if (var->is_qml_global()) {
++      pos += OS::SNPrintF(buf + pos, ":QML");
++    }
+     OS::SNPrintF(buf + pos, ")");
+     PrintLiteralIndented(buf.start(), value, true);
+   }
+diff --git a/src/runtime.cc b/src/runtime.cc
+index 5a850e9..0388a77 100644
+--- a/src/runtime.cc
++++ b/src/runtime.cc
+@@ -1213,19 +1213,23 @@ static Failure* ThrowRedeclarationError(Isolate* isolate,
+ RUNTIME_FUNCTION(MaybeObject*, Runtime_DeclareGlobals) {
+   ASSERT(args.length() == 3);
+   HandleScope scope(isolate);
+-  Handle<GlobalObject> global = Handle<GlobalObject>(
+-      isolate->context()->global());
+ 
+   Handle<Context> context = args.at<Context>(0);
+   CONVERT_ARG_CHECKED(FixedArray, pairs, 1);
+   CONVERT_SMI_ARG_CHECKED(flags, 2);
+ 
++  Handle<JSObject> js_global = Handle<JSObject>(isolate->context()->global());
++  Handle<JSObject> qml_global = Handle<JSObject>(isolate->context()->qml_global());
++
+   // Traverse the name/value pairs and set the properties.
+   int length = pairs->length();
+-  for (int i = 0; i < length; i += 2) {
++  for (int i = 0; i < length; i += 3) {
+     HandleScope scope(isolate);
+     Handle<String> name(String::cast(pairs->get(i)));
+     Handle<Object> value(pairs->get(i + 1), isolate);
++    Handle<Smi> is_qml_global(Smi::cast(pairs->get(i + 2)));
++
++    Handle<JSObject> global = is_qml_global->value()?qml_global:js_global;
+ 
+     // We have to declare a global const property. To capture we only
+     // assign to it when evaluating the assignment for "const x =
+@@ -1414,19 +1418,24 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeVarGlobal) {
+   NoHandleAllocation nha;
+   // args[0] == name
+   // args[1] == strict_mode
+-  // args[2] == value (optional)
++  // args[2] == qml_mode
++  // args[3] == value (optional)
+ 
+   // Determine if we need to assign to the variable if it already
+   // exists (based on the number of arguments).
+-  RUNTIME_ASSERT(args.length() == 2 || args.length() == 3);
+-  bool assign = args.length() == 3;
++  RUNTIME_ASSERT(args.length() == 3 || args.length() == 4);
++  bool assign = args.length() == 4;
+ 
+   CONVERT_ARG_CHECKED(String, name, 0);
+-  GlobalObject* global = isolate->context()->global();
+   RUNTIME_ASSERT(args[1]->IsSmi());
+   StrictModeFlag strict_mode = static_cast<StrictModeFlag>(args.smi_at(1));
+   ASSERT(strict_mode == kStrictMode || strict_mode == kNonStrictMode);
+ 
++  RUNTIME_ASSERT(args[2]->IsSmi());
++  int qml_mode = Smi::cast(args[2])->value();
++
++  JSObject* global = qml_mode?isolate->context()->qml_global():isolate->context()->global();
++
+   // According to ECMA-262, section 12.2, page 62, the property must
+   // not be deletable.
+   PropertyAttributes attributes = DONT_DELETE;
+@@ -1454,7 +1463,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeVarGlobal) {
+         // Found an interceptor that's not read only.
+         if (assign) {
+           return raw_holder->SetProperty(
+-              &lookup, *name, args[2], attributes, strict_mode);
++              &lookup, *name, args[3], attributes, strict_mode);
+         } else {
+           return isolate->heap()->undefined_value();
+         }
+@@ -1464,9 +1473,9 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeVarGlobal) {
+   }
+ 
+   // Reload global in case the loop above performed a GC.
+-  global = isolate->context()->global();
++  global = qml_mode?isolate->context()->qml_global():isolate->context()->global();
+   if (assign) {
+-    return global->SetProperty(*name, args[2], attributes, strict_mode, true);
++    return global->SetProperty(*name, args[3], attributes, strict_mode, true);
+   }
+   return isolate->heap()->undefined_value();
+ }
+@@ -1476,12 +1485,15 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeConstGlobal) {
+   // All constants are declared with an initial value. The name
+   // of the constant is the first argument and the initial value
+   // is the second.
+-  RUNTIME_ASSERT(args.length() == 2);
++  RUNTIME_ASSERT(args.length() == 3);
+   CONVERT_ARG_CHECKED(String, name, 0);
+   Handle<Object> value = args.at<Object>(1);
+ 
++  RUNTIME_ASSERT(args[2]->IsSmi());
++  int qml_mode = Smi::cast(args[2])->value();
++
+   // Get the current global object from top.
+-  GlobalObject* global = isolate->context()->global();
++  JSObject* global = qml_mode?isolate->context()->qml_global():isolate->context()->global();
+ 
+   // According to ECMA-262, section 12.2, page 62, the property must
+   // not be deletable. Since it's a const, it must be READ_ONLY too.
+@@ -1505,7 +1517,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_InitializeConstGlobal) {
+     // Restore global object from context (in case of GC) and continue
+     // with setting the value.
+     HandleScope handle_scope(isolate);
+-    Handle<GlobalObject> global(isolate->context()->global());
++    Handle<JSObject> global(qml_mode?isolate->context()->qml_global():isolate->context()->global());
+ 
+     // BUG 1213575: Handle the case where we have to set a read-only
+     // property through an interceptor and only do it if it's
+@@ -9204,7 +9216,8 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_CompileString) {
+   Handle<SharedFunctionInfo> shared = Compiler::CompileEval(source,
+                                                             context,
+                                                             true,
+-                                                            kNonStrictMode);
++                                                            kNonStrictMode,
++                                                            false);
+   if (shared.is_null()) return Failure::Exception();
+   Handle<JSFunction> fun =
+       isolate->factory()->NewFunctionFromSharedFunctionInfo(shared,
+@@ -9217,7 +9230,8 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_CompileString) {
+ static ObjectPair CompileGlobalEval(Isolate* isolate,
+                                     Handle<String> source,
+                                     Handle<Object> receiver,
+-                                    StrictModeFlag strict_mode) {
++                                    StrictModeFlag strict_mode, 
++                                    bool qml_mode) {
+   Handle<Context> context = Handle<Context>(isolate->context());
+   Handle<Context> global_context = Handle<Context>(context->global_context());
+ 
+@@ -9235,7 +9249,8 @@ static ObjectPair CompileGlobalEval(Isolate* isolate,
+       source,
+       Handle<Context>(isolate->context()),
+       context->IsGlobalContext(),
+-      strict_mode);
++      strict_mode,
++      qml_mode);
+   if (shared.is_null()) return MakePair(Failure::Exception(), NULL);
+   Handle<JSFunction> compiled =
+       isolate->factory()->NewFunctionFromSharedFunctionInfo(
+@@ -9245,7 +9260,7 @@ static ObjectPair CompileGlobalEval(Isolate* isolate,
+ 
+ 
+ RUNTIME_FUNCTION(ObjectPair, Runtime_ResolvePossiblyDirectEval) {
+-  ASSERT(args.length() == 4);
++  ASSERT(args.length() == 5);
+ 
+   HandleScope scope(isolate);
+   Handle<Object> callee = args.at<Object>(0);
+@@ -9308,15 +9323,17 @@ RUNTIME_FUNCTION(ObjectPair, Runtime_ResolvePossiblyDirectEval) {
+   }
+ 
+   ASSERT(args[3]->IsSmi());
++  ASSERT(args[4]->IsSmi());
+   return CompileGlobalEval(isolate,
+                            args.at<String>(1),
+                            args.at<Object>(2),
+-                           static_cast<StrictModeFlag>(args.smi_at(3)));
++                           static_cast<StrictModeFlag>(args.smi_at(3)),
++                           Smi::cast(args[4])->value());
+ }
+ 
+ 
+ RUNTIME_FUNCTION(ObjectPair, Runtime_ResolvePossiblyDirectEvalNoLookup) {
+-  ASSERT(args.length() == 4);
++  ASSERT(args.length() == 5);
+ 
+   HandleScope scope(isolate);
+   Handle<Object> callee = args.at<Object>(0);
+@@ -9329,10 +9346,12 @@ RUNTIME_FUNCTION(ObjectPair, Runtime_ResolvePossiblyDirectEvalNoLookup) {
+   }
+ 
+   ASSERT(args[3]->IsSmi());
++  ASSERT(args[4]->IsSmi());
+   return CompileGlobalEval(isolate,
+                            args.at<String>(1),
+                            args.at<Object>(2),
+-                           static_cast<StrictModeFlag>(args.smi_at(3)));
++                           static_cast<StrictModeFlag>(args.smi_at(3)),
++                           Smi::cast(args[4])->value());
+ }
+ 
+ 
+@@ -11771,6 +11790,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugEvaluate) {
+   Handle<JSFunction> function(JSFunction::cast(frame->function()));
+   Handle<SerializedScopeInfo> scope_info(function->shared()->scope_info());
+   ScopeInfo<> sinfo(*scope_info);
++  bool qml_mode = function->shared()->qml_mode();
+ 
+   // Traverse the saved contexts chain to find the active context for the
+   // selected frame.
+@@ -11840,7 +11860,8 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugEvaluate) {
+       Compiler::CompileEval(function_source,
+                             context,
+                             context->IsGlobalContext(),
+-                            kNonStrictMode);
++                            kNonStrictMode,
++                            qml_mode);
+   if (shared.is_null()) return Failure::Exception();
+   Handle<JSFunction> compiled_function =
+       isolate->factory()->NewFunctionFromSharedFunctionInfo(shared, context);
+@@ -11850,7 +11871,8 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugEvaluate) {
+   Handle<Object> receiver(frame->receiver(), isolate);
+   Handle<Object> evaluation_function =
+       Execution::Call(compiled_function, receiver, 0, NULL,
+-                      &has_pending_exception);
++                      &has_pending_exception, false,
++                      Handle<Object>(function->context()->qml_global()));
+   if (has_pending_exception) return Failure::Exception();
+ 
+   Handle<Object> arguments = GetArgumentsObject(isolate,
+@@ -11930,7 +11952,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_DebugEvaluateGlobal) {
+   // Currently, the eval code will be executed in non-strict mode,
+   // even in the strict code context.
+   Handle<SharedFunctionInfo> shared =
+-      Compiler::CompileEval(source, context, is_global, kNonStrictMode);
++      Compiler::CompileEval(source, context, is_global, kNonStrictMode, false);
+   if (shared.is_null()) return Failure::Exception();
+   Handle<JSFunction> compiled_function =
+       Handle<JSFunction>(
+diff --git a/src/runtime.h b/src/runtime.h
+index c6f7773..284f723 100644
+--- a/src/runtime.h
++++ b/src/runtime.h
+@@ -257,8 +257,8 @@ namespace internal {
+   \
+   /* Eval */ \
+   F(GlobalReceiver, 1, 1) \
+-  F(ResolvePossiblyDirectEval, 4, 2) \
+-  F(ResolvePossiblyDirectEvalNoLookup, 4, 2) \
++  F(ResolvePossiblyDirectEval, 5, 2) \
++  F(ResolvePossiblyDirectEvalNoLookup, 5, 2) \
+   \
+   F(SetProperty, -1 /* 4 or 5 */, 1) \
+   F(DefineOrRedefineDataProperty, 4, 1) \
+@@ -325,8 +325,8 @@ namespace internal {
+   /* Declarations and initialization */ \
+   F(DeclareGlobals, 3, 1) \
+   F(DeclareContextSlot, 4, 1) \
+-  F(InitializeVarGlobal, -1 /* 2 or 3 */, 1) \
+-  F(InitializeConstGlobal, 2, 1) \
++  F(InitializeVarGlobal, -1 /* 3 or 4 */, 1) \
++  F(InitializeConstGlobal, 3, 1) \
+   F(InitializeConstContextSlot, 3, 1) \
+   F(OptimizeObjectForAddingMultipleProperties, 2, 1) \
+   \
+diff --git a/src/scopes.cc b/src/scopes.cc
+index d5a7a9f..25921fa 100644
+--- a/src/scopes.cc
++++ b/src/scopes.cc
+@@ -35,6 +35,8 @@
+ 
+ #include "allocation-inl.h"
+ 
++#include "debug.h"
++
+ namespace v8 {
+ namespace internal {
+ 
+@@ -202,6 +204,7 @@ void Scope::SetDefaults(Type type,
+   scope_calls_eval_ = false;
+   // Inherit the strict mode from the parent scope.
+   strict_mode_ = (outer_scope != NULL) && outer_scope->strict_mode_;
++  qml_mode_ = (outer_scope != NULL) && outer_scope->qml_mode_;
+   outer_scope_calls_eval_ = false;
+   outer_scope_calls_non_strict_eval_ = false;
+   inner_scope_calls_eval_ = false;
+@@ -923,6 +926,25 @@ void Scope::ResolveVariable(Scope* global_scope,
+         ASSERT(global_scope != NULL);
+         var = global_scope->DeclareGlobal(proxy->name());
+ 
++        if (qml_mode_) {
++          Handle<GlobalObject> global = Isolate::Current()->global();
++
++#ifdef ENABLE_DEBUGGER_SUPPORT
++          if (Isolate::Current()->debug()->IsLoaded() && Isolate::Current()->debug()->InDebugger()) {
++            //Get the context before the debugger was entered.
++            SaveContext *save = Isolate::Current()->save_context();
++            while (save != NULL && *save->context() == *Isolate::Current()->debug()->debug_context())
++              save = save->prev();
++
++            global = Handle<GlobalObject>(save->context()->global());
++          }
++#endif
++
++          if (!global->HasProperty(*(proxy->name()))) {
++            var->set_is_qml_global(true);
++          }
++        }
++
+       } else if (scope_inside_with_) {
+         // If we are inside a with statement we give up and look up
+         // the variable at runtime.
+@@ -944,6 +966,25 @@ void Scope::ResolveVariable(Scope* global_scope,
+         if (context->GlobalIfNotShadowedByEval(proxy->name())) {
+           var = NonLocal(proxy->name(), Variable::DYNAMIC_GLOBAL);
+ 
++          if (qml_mode_) {
++            Handle<GlobalObject> global = Isolate::Current()->global();
++
++#ifdef ENABLE_DEBUGGER_SUPPORT
++            if (Isolate::Current()->debug()->IsLoaded() && Isolate::Current()->debug()->InDebugger()) {
++              //Get the context before the debugger was entered.
++              SaveContext *save = Isolate::Current()->save_context();
++              while (save != NULL && *save->context() == *Isolate::Current()->debug()->debug_context())
++                save = save->prev();
++
++              global = Handle<GlobalObject>(save->context()->global());
++            }
++#endif
++
++            if (qml_mode_ && !global->HasProperty(*(proxy->name()))) {
++              var->set_is_qml_global(true);
++            }
++          }
++
+         } else {
+           var = NonLocal(proxy->name(), Variable::DYNAMIC);
+         }
+@@ -954,6 +995,26 @@ void Scope::ResolveVariable(Scope* global_scope,
+         // variable is global unless it is shadowed by eval-introduced
+         // variables.
+         var = NonLocal(proxy->name(), Variable::DYNAMIC_GLOBAL);
++
++        if (qml_mode_) {
++          Handle<GlobalObject> global = Isolate::Current()->global();
++
++#ifdef ENABLE_DEBUGGER_SUPPORT
++          if (Isolate::Current()->debug()->IsLoaded() && Isolate::Current()->debug()->InDebugger()) {
++            //Get the context before the debugger was entered.
++            SaveContext *save = Isolate::Current()->save_context();
++            while (save != NULL && *save->context() == *Isolate::Current()->debug()->debug_context())
++              save = save->prev();
++
++            global = Handle<GlobalObject>(save->context()->global());
++          }
++#endif
++
++          if (qml_mode_ && !global->HasProperty(*(proxy->name()))) {
++            var->set_is_qml_global(true);
++          }
++        }
++
+       }
+     }
+   }
+diff --git a/src/scopes.h b/src/scopes.h
+index 2917a63..0f1ed6d 100644
+--- a/src/scopes.h
++++ b/src/scopes.h
+@@ -206,6 +206,11 @@ class Scope: public ZoneObject {
+     strict_mode_ = FLAG_strict_mode;
+   }
+ 
++  // Enable qml mode for this scope
++  void EnableQmlMode() {
++    qml_mode_ = true;
++  }
++
+   // ---------------------------------------------------------------------------
+   // Predicates.
+ 
+@@ -216,6 +221,7 @@ class Scope: public ZoneObject {
+   bool is_catch_scope() const { return type_ == CATCH_SCOPE; }
+   bool is_block_scope() const { return type_ == BLOCK_SCOPE; }
+   bool is_strict_mode() const { return strict_mode_; }
++  bool is_qml_mode() const { return qml_mode_; }
+   bool is_strict_mode_eval_scope() const {
+     return is_eval_scope() && is_strict_mode();
+   }
+@@ -381,6 +387,8 @@ class Scope: public ZoneObject {
+   bool scope_calls_eval_;
+   // This scope is a strict mode scope.
+   bool strict_mode_;
++  // This scope is a qml mode scope.
++  bool qml_mode_;
+ 
+   // Computed via PropagateScopeInfo.
+   bool outer_scope_calls_eval_;
+diff --git a/src/variables.cc b/src/variables.cc
+index 971061b..da07620 100644
+--- a/src/variables.cc
++++ b/src/variables.cc
+@@ -67,7 +67,8 @@ Variable::Variable(Scope* scope,
+     local_if_not_shadowed_(NULL),
+     is_valid_LHS_(is_valid_LHS),
+     is_accessed_from_inner_scope_(false),
+-    is_used_(false) {
++    is_used_(false),
++    is_qml_global_(false) {
+   // names must be canonicalized for fast equality checks
+   ASSERT(name->IsSymbol());
+ }
+diff --git a/src/variables.h b/src/variables.h
+index 56c8dab..4d27f98 100644
+--- a/src/variables.h
++++ b/src/variables.h
+@@ -174,6 +174,8 @@ class Variable: public ZoneObject {
+     index_ = index;
+   }
+ 
++  bool is_qml_global() const { return is_qml_global_; }
++  void set_is_qml_global(bool is_qml_global) { is_qml_global_ = is_qml_global; }
+  private:
+   Scope* scope_;
+   Handle<String> name_;
+@@ -190,6 +192,9 @@ class Variable: public ZoneObject {
+   // Usage info.
+   bool is_accessed_from_inner_scope_;  // set by variable resolver
+   bool is_used_;
++
++  // QML info
++  bool is_qml_global_;
+ };
+ 
+ 
+diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
+index 8d9dba7..6ab12fc 100644
+--- a/src/x64/code-stubs-x64.cc
++++ b/src/x64/code-stubs-x64.cc
+@@ -139,6 +139,10 @@ void FastNewContextStub::Generate(MacroAssembler* masm) {
+   __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+   __ movq(Operand(rax, Context::SlotOffset(Context::GLOBAL_INDEX)), rbx);
+ 
++  // Copy the qmlglobal object from the previous context.
++  __ movq(rbx, Operand(rsi, Context::SlotOffset(Context::QML_GLOBAL_INDEX)));
++  __ movq(Operand(rax, Context::SlotOffset(Context::QML_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++) {
+diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
+index 1d9b8ff..08b3872 100644
+--- a/src/x64/full-codegen-x64.cc
++++ b/src/x64/full-codegen-x64.cc
+@@ -173,12 +173,13 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment cmnt(masm_, "[ Allocate local context");
+     // Argument to NewContext is the function, which is still in rdi.
+     __ push(rdi);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -1129,10 +1130,10 @@ void FullCodeGenerator::EmitLoadGlobalCheckExtensions(Variable* var,
+ 
+   // All extension objects were empty and it is safe to use a global
+   // load IC call.
+-  __ movq(rax, GlobalObjectOperand());
++  __ movq(rax, var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+   __ Move(rcx, var->name());
+   Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+-  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF)
++  RelocInfo::Mode mode = (typeof_state == INSIDE_TYPEOF || var->is_qml_global())
+       ? RelocInfo::CODE_TARGET
+       : RelocInfo::CODE_TARGET_CONTEXT;
+   __ call(ic, mode);
+@@ -1207,9 +1208,9 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy) {
+       // Use inline caching. Variable name is passed in rcx and the global
+       // object on the stack.
+       __ Move(rcx, var->name());
+-      __ movq(rax, GlobalObjectOperand());
++      __ movq(rax, var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+       Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+-      __ call(ic, RelocInfo::CODE_TARGET_CONTEXT);
++      __ call(ic, var->is_qml_global() ? RelocInfo::CODE_TARGET : RelocInfo::CODE_TARGET_CONTEXT);
+       context()->Plug(rax);
+       break;
+     }
+@@ -1750,7 +1751,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var,
+   if (var->IsUnallocated()) {
+     // Global var, const, or let.
+     __ Move(rcx, var->name());
+-    __ movq(rdx, GlobalObjectOperand());
++    __ movq(rdx, var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+     Handle<Code> ic = is_strict_mode()
+         ? isolate()->builtins()->StoreIC_Initialize_Strict()
+         : isolate()->builtins()->StoreIC_Initialize();
+@@ -2034,9 +2035,12 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(ResolveEvalFlag flag,
+   }
+   __ Push(Smi::FromInt(strict_mode));
+ 
++  // Push the qml mode flag
++  __ Push(Smi::FromInt(is_qml_mode()));
++
+   __ CallRuntime(flag == SKIP_CONTEXT_LOOKUP
+                  ? Runtime::kResolvePossiblyDirectEvalNoLookup
+-                 : Runtime::kResolvePossiblyDirectEval, 4);
++                 : Runtime::kResolvePossiblyDirectEval, 5);
+ }
+ 
+ 
+@@ -2105,8 +2109,8 @@ void FullCodeGenerator::VisitCall(Call* expr) {
+   } else if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     // Call to a global variable.  Push global object as receiver for the
+     // call IC lookup.
+-    __ push(GlobalObjectOperand());
+-    EmitCallWithIC(expr, proxy->name(), RelocInfo::CODE_TARGET_CONTEXT);
++    __ push(proxy->var()->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
++    EmitCallWithIC(expr, proxy->name(), proxy->var()->is_qml_global() ? RelocInfo::CODE_TARGET : RelocInfo::CODE_TARGET_CONTEXT);
+   } else if (proxy != NULL && proxy->var()->IsLookupSlot()) {
+     // Call to a lookup slot (dynamically introduced variable).
+     Label slow, done;
+@@ -3552,7 +3556,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
+         // but "delete this" is allowed.
+         ASSERT(strict_mode_flag() == kNonStrictMode || var->is_this());
+         if (var->IsUnallocated()) {
+-          __ push(GlobalObjectOperand());
++          __ push(var->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+           __ Push(var->name());
+           __ Push(Smi::FromInt(kNonStrictMode));
+           __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
+@@ -3850,7 +3854,7 @@ void FullCodeGenerator::VisitForTypeofValue(Expression* expr) {
+   if (proxy != NULL && proxy->var()->IsUnallocated()) {
+     Comment cmnt(masm_, "Global variable");
+     __ Move(rcx, proxy->name());
+-    __ movq(rax, GlobalObjectOperand());
++    __ movq(rax, proxy->var()->is_qml_global() ? QmlGlobalObjectOperand() : GlobalObjectOperand());
+     Handle<Code> ic = isolate()->builtins()->LoadIC_Initialize();
+     // Use a regular load, not a contextual load, to avoid a reference
+     // error.
+diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
+index 45aaad7..08050f0 100644
+--- a/src/x64/lithium-codegen-x64.cc
++++ b/src/x64/lithium-codegen-x64.cc
+@@ -196,12 +196,13 @@ bool LCodeGen::GeneratePrologue() {
+ 
+   // Possibly allocate a local context.
+   int heap_slots = scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+-  if (heap_slots > 0) {
++  if (heap_slots > 0 ||
++      (scope()->is_qml_mode() && scope()->is_global_scope())) {
+     Comment(";;; Allocate local context");
+     // Argument to NewContext is the function, which is still in rdi.
+     __ push(rdi);
+     if (heap_slots <= FastNewContextStub::kMaximumSlots) {
+-      FastNewContextStub stub(heap_slots);
++      FastNewContextStub stub((heap_slots < 0)?0:heap_slots);
+       __ CallStub(&stub);
+     } else {
+       __ CallRuntime(Runtime::kNewFunctionContext, 1);
+@@ -2581,7 +2582,7 @@ void LCodeGen::DoOuterContext(LOuterContext* instr) {
+ 
+ void LCodeGen::DoGlobalObject(LGlobalObject* instr) {
+   Register result = ToRegister(instr->result());
+-  __ movq(result, GlobalObjectOperand());
++  __ movq(result, instr->qml_global()?QmlGlobalObjectOperand():GlobalObjectOperand());
+ }
+ 
+ 
+diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
+index a67a593..a243fef 100644
+--- a/src/x64/lithium-x64.cc
++++ b/src/x64/lithium-x64.cc
+@@ -1117,7 +1117,7 @@ LInstruction* LChunkBuilder::DoOuterContext(HOuterContext* instr) {
+ 
+ 
+ LInstruction* LChunkBuilder::DoGlobalObject(HGlobalObject* instr) {
+-  return DefineAsRegister(new LGlobalObject);
++  return DefineAsRegister(new LGlobalObject(instr->qml_global()));
+ }
+ 
+ 
+diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
+index d43a86a..cf89181 100644
+--- a/src/x64/lithium-x64.h
++++ b/src/x64/lithium-x64.h
+@@ -1301,7 +1301,13 @@ class LOuterContext: public LTemplateInstruction<1, 1, 0> {
+ 
+ class LGlobalObject: public LTemplateInstruction<1, 0, 0> {
+  public:
++  explicit LGlobalObject(bool qml_global) : qml_global_(qml_global) {}
++
+   DECLARE_CONCRETE_INSTRUCTION(GlobalObject, "global-object")
++  
++  bool qml_global() { return qml_global_; }
++ private:
++  bool qml_global_;
+ };
+ 
+ 
+diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
+index 7e0ba00..744ce20 100644
+--- a/src/x64/macro-assembler-x64.h
++++ b/src/x64/macro-assembler-x64.h
+@@ -1413,6 +1413,11 @@ static inline Operand GlobalObjectOperand() {
+ }
+ 
+ 
++static inline Operand QmlGlobalObjectOperand() {
++  return ContextOperand(rsi, Context::QML_GLOBAL_INDEX);
++}
++
++
+ // Provides access to exit frame stack space (not GCed).
+ static inline Operand StackSpaceOperand(int index) {
+ #ifdef _WIN64
+-- 
+1.7.4.4
+