[Interpreter] Add support for global declarations and load/store of global variables

src/compiler/interpreter-assembler.cc

 // Copyright 2015 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/compiler/interpreter-assembler.h"
 
 #include <ostream>
 
 #include "src/code-factory.h"
 #include "src/compiler/graph.h"
@@ skipping 256 matching lines @@
   return raw_assembler_->Load(kMachAnyTagged, constant_pool, entry_offset);
 }
 
 
 Node* InterpreterAssembler::LoadObjectField(Node* object, int offset) {
   return raw_assembler_->Load(kMachAnyTagged, object,
                               IntPtrConstant(offset - kHeapObjectTag));
 }
 
 
-Node* InterpreterAssembler::LoadContextSlot(Node* context, int slot_index) {
-  return raw_assembler_->Load(kMachAnyTagged, context,
-                              IntPtrConstant(Context::SlotOffset(slot_index)));
+Node* InterpreterAssembler::LoadContextSlot(Node* context, Node* slot_index) {
+  Node* offset =
+      IntPtrAdd(WordShl(slot_index, kPointerSizeLog2),
+                Int32Constant(Context::kHeaderSize - kHeapObjectTag));
+  return raw_assembler_->Load(kMachAnyTagged, context, offset);
 }
 
 
-Node* InterpreterAssembler::LoadContextSlot(int slot_index) {
-  return LoadContextSlot(ContextTaggedPointer(), slot_index);
-}
-
-
 Node* InterpreterAssembler::LoadTypeFeedbackVector() {
   Node* function = raw_assembler_->Load(
       kMachAnyTagged, RegisterFileRawPointer(),
       IntPtrConstant(InterpreterFrameConstants::kFunctionFromRegisterPointer));
   Node* shared_info =
       LoadObjectField(function, JSFunction::kSharedFunctionInfoOffset);
   Node* vector =
       LoadObjectField(shared_info, SharedFunctionInfo::kFeedbackVectorOffset);
   return vector;
 }
@@ skipping 207 matching lines @@
   return raw_assembler_->schedule();
 }
 
 
 Zone* InterpreterAssembler::zone() { return raw_assembler_->zone(); }
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8