[Interpreter] Add support for loading globals in the interpreter.

src/interpreter/bytecode-array-iterator.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/interpreter/bytecode-array-iterator.h"
 
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 14 matching lines @@
 }
 
 
 Bytecode BytecodeArrayIterator::current_bytecode() const {
   DCHECK(!done());
   uint8_t current_byte = bytecode_array()->get(bytecode_offset_);
   return interpreter::Bytecodes::FromByte(current_byte);
 }
 
 
-uint8_t BytecodeArrayIterator::GetOperand(int operand_index,
-                                          OperandType operand_type) const {
+uint8_t BytecodeArrayIterator::GetRawOperand(int operand_index) const {

[oth, 2015/09/24 10:14:00]

Although more work in the test, making GetOperand public would limit potential
misuses of GetRawOperand().

[rmcilroy, 2015/09/24 11:20:12]

Sounds good, done.

   DCHECK_GE(operand_index, 0);
   DCHECK_LT(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
-  DCHECK_EQ(operand_type,
-            Bytecodes::GetOperandType(current_bytecode(), operand_index));
   int operands_start = bytecode_offset_ + 1;
   return bytecode_array()->get(operands_start + operand_index);
 }
 
 
 int8_t BytecodeArrayIterator::GetSmi8Operand(int operand_index) const {
-  uint8_t operand = GetOperand(operand_index, OperandType::kImm8);
+  DCHECK_EQ(OperandType::kImm8,
+            Bytecodes::GetOperandType(current_bytecode(), operand_index));
+  uint8_t operand = GetRawOperand(operand_index);
   return static_cast<int8_t>(operand);
 }
 
 
 int BytecodeArrayIterator::GetIndexOperand(int operand_index) const {
-  uint8_t operand = GetOperand(operand_index, OperandType::kIdx);
+  DCHECK_EQ(OperandType::kIdx,
+            Bytecodes::GetOperandType(current_bytecode(), operand_index));
+  uint8_t operand = GetRawOperand(operand_index);
   return static_cast<int>(operand);
 }
 
 
 Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
-  uint8_t operand = GetOperand(operand_index, OperandType::kReg);
+  DCHECK_EQ(OperandType::kReg,
+            Bytecodes::GetOperandType(current_bytecode(), operand_index));
+  uint8_t operand = GetRawOperand(operand_index);
   return Register::FromOperand(operand);
 }
 
 
 Handle<Object> BytecodeArrayIterator::GetConstantForIndexOperand(
     int operand_index) const {
   Handle<FixedArray> constants = handle(bytecode_array()->constant_pool());
   return FixedArray::get(constants, GetIndexOperand(operand_index));
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8