harmony-scoping: Implement StoreIC handler for stores to global contexts.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 3115 matching lines @@
   HInstruction* global_object = Add<HLoadNamedField>(
       context, static_cast<HValue*>(NULL),
       HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
   HObjectAccess access = HObjectAccess::ForObservableJSObjectOffset(
       GlobalObject::kNativeContextOffset);
   return Add<HLoadNamedField>(
       global_object, static_cast<HValue*>(NULL), access);
 }
 
 
+HInstruction* HGraphBuilder::BuildGetGlobalContext(int context_index) {
+  HValue* native_context = BuildGetNativeContext();
+  HValue* global_context_table = Add<HLoadNamedField>(
+      native_context, static_cast<HValue*>(NULL),
+      HObjectAccess::ForContextSlot(Context::GLOBAL_CONTEXT_TABLE_INDEX));
+  return Add<HLoadNamedField>(global_context_table, static_cast<HValue*>(NULL),
+                              HObjectAccess::ForGlobalContext(context_index));
+}
+
+
 HInstruction* HGraphBuilder::BuildGetNativeContext() {
   // Get the global context, then the native context
   HValue* global_object = Add<HLoadNamedField>(
       context(), static_cast<HValue*>(NULL),
       HObjectAccess::ForContextSlot(Context::GLOBAL_OBJECT_INDEX));
   return Add<HLoadNamedField>(
       global_object, static_cast<HValue*>(NULL),
       HObjectAccess::ForObservableJSObjectOffset(
           GlobalObject::kNativeContextOffset));
 }
@@ skipping 3369 matching lines @@
 
 
 // Because not every expression has a position and there is not common
 // superclass of Assignment and CountOperation, we cannot just pass the
 // owning expression instead of position and ast_id separately.
 void HOptimizedGraphBuilder::HandleGlobalVariableAssignment(
     Variable* var,
     HValue* value,
     BailoutId ast_id) {
   Handle<GlobalObject> global(current_info()->global_object());
+
+  if (FLAG_harmony_scoping) {
+    Handle<GlobalContextTable> global_contexts(
+        global->native_context()->global_context_table());
+    GlobalContextTable::LookupResult lookup;
+    if (GlobalContextTable::Lookup(global_contexts, var->name(), &lookup)) {
+      Handle<Context> global_context =
+          GlobalContextTable::GetContext(global_contexts, lookup.context_index);
+      HStoreNamedField* instr = Add<HStoreNamedField>(
+          Add<HConstant>(global_context),
+          HObjectAccess::ForContextSlot(lookup.slot_index), value);
+      USE(instr);
+      DCHECK(instr->HasObservableSideEffects());
+      Add<HSimulate>(ast_id, REMOVABLE_SIMULATE);
+      return;
+    }
+  }
+
   LookupIterator it(global, var->name(), LookupIterator::OWN_SKIP_INTERCEPTOR);
   GlobalPropertyAccess type = LookupGlobalProperty(var, &it, STORE);
   if (type == kUseCell) {
     Handle<PropertyCell> cell = it.GetPropertyCell();
     if (cell->type()->IsConstant()) {
       Handle<Object> constant = cell->type()->AsConstant()->Value();
       if (value->IsConstant()) {
         HConstant* c_value = HConstant::cast(value);
         if (!constant.is_identical_to(c_value->handle(isolate()))) {
           Add<HDeoptimize>("Constant global variable assignment",
@@ skipping 6166 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal