harmony-scoping: Implement LoadIC handler for loads from global contexts.

src/code-stubs.h

 // Copyright 2012 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.
 
 #ifndef V8_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 51 matching lines @@
   V(CreateAllocationSite)                   \
   V(ElementsTransitionAndStore)             \
   V(FastCloneShallowArray)                  \
   V(FastCloneShallowObject)                 \
   V(FastNewClosure)                         \
   V(FastNewContext)                         \
   V(InternalArrayNArgumentsConstructor)     \
   V(InternalArrayNoArgumentConstructor)     \
   V(InternalArraySingleArgumentConstructor) \
   V(KeyedLoadGeneric)                       \
+  V(LoadGlobalContextField)                 \
   V(LoadDictionaryElement)                  \
   V(LoadFastElement)                        \
   V(MegamorphicLoad)                        \
   V(NameDictionaryLookup)                   \
   V(NumberToString)                         \
   V(RegExpConstructResult)                  \
   V(StoreFastElement)                       \
   V(StringAdd)                              \
   V(ToBoolean)                              \
   V(TransitionElementsKind)                 \
@@ skipping 1931 matching lines @@
   class SkipFastPathBits:
       public BitField<int, 2 * kBitsPerRegisterNumber + 4, 1> {};  // NOLINT
   class SSE3Bits:
       public BitField<int, 2 * kBitsPerRegisterNumber + 5, 1> {};  // NOLINT
 
   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
   DEFINE_PLATFORM_CODE_STUB(DoubleToI, PlatformCodeStub);
 };
 
 
+class LoadGlobalContextFieldStub : public HandlerStub {
+ public:
+  LoadGlobalContextFieldStub(
+      Isolate* isolate, const GlobalContextTable::LookupResult* lookup_result)
+      : HandlerStub(isolate) {
+    DCHECK(Accepted(lookup_result));
+    set_sub_minor_key(ContextIndexBits::encode(lookup_result->context_index) |
+                      SlotIndexBits::encode(lookup_result->slot_index));
+  }
+
+  int context_index() const {
+    return ContextIndexBits::decode(sub_minor_key());
+  }
+
+  int slot_index() const { return SlotIndexBits::decode(sub_minor_key()); }
+
+  static bool Accepted(const GlobalContextTable::LookupResult* lookup_result) {
+    return lookup_result->context_index >= 0 &&
+           lookup_result->slot_index >= 0 &&
+           lookup_result->context_index < (1 << kContextIndexBits) &&
+           lookup_result->slot_index < (1 << kSlotIndexBits);
+  }
+
+ private:
+  static const int kContextIndexBits = 13;
+  static const int kSlotIndexBits = 13;
+  class ContextIndexBits : public BitField<int, 0, kContextIndexBits> {};
+  class SlotIndexBits
+      : public BitField<int, kContextIndexBits, kSlotIndexBits> {};
+
+  virtual Code::Kind kind() const { return Code::LOAD_IC; }
+  virtual Code::StubType GetStubType() OVERRIDE { return Code::FAST; }
+
+
+  virtual CallInterfaceDescriptor GetCallInterfaceDescriptor() OVERRIDE {
+    return ContextOnlyDescriptor(isolate());
+  }
+
+  DEFINE_HANDLER_CODE_STUB(LoadGlobalContextField, HandlerStub);
+};
+
+
 class LoadFastElementStub : public HydrogenCodeStub {
  public:
   LoadFastElementStub(Isolate* isolate, bool is_js_array,
                       ElementsKind elements_kind)
       : HydrogenCodeStub(isolate) {
     set_sub_minor_key(ElementsKindBits::encode(elements_kind) |
                       IsJSArrayBits::encode(is_js_array));
   }
 
   bool is_js_array() const { return IsJSArrayBits::decode(sub_minor_key()); }
@@ skipping 519 matching lines @@
 
 #undef DEFINE_CALL_INTERFACE_DESCRIPTOR
 #undef DEFINE_PLATFORM_CODE_STUB
 #undef DEFINE_HANDLER_CODE_STUB
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_