[Interpreter] Bytecode graph builder

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 {
+namespace interpreter {
+
+BytecodeArrayIterator::BytecodeArrayIterator(
+    Handle<BytecodeArray> bytecode_array)
+    : bytecode_array_(bytecode_array), bytecode_offset_(0) {}
+
+
+void BytecodeArrayIterator::Advance() {
+  bytecode_offset_ += Bytecodes::Size(current_bytecode());
+}
+
+
+bool BytecodeArrayIterator::done() const {
+  return bytecode_offset_ >= bytecode_array()->length();
+}
+
+
+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 {
+  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);
+  return static_cast<int8_t>(operand);
+}
+
+
+int BytecodeArrayIterator::GetIndexOperand(int operand_index) const {
+  uint8_t operand = GetOperand(operand_index, OperandType::kIdx);
+  return static_cast<int>(operand);
+}
+
+
+Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
+  uint8_t operand = GetOperand(operand_index, OperandType::kReg);
+  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));

[rmcilroy, 2015/09/10 10:19:43]

this should be "constants->get(GetIndexOperand(operand_index));" I think.

[oth, 2015/09/10 13:59:06]

The static version returns a handle for the element that this method returns.
The member version returns bare object pointer. The current path might be
cleaner than cons-ing up handle here. WDYT?

[rmcilroy, 2015/09/10 14:06:28]

Ahh you're right sorry. Strange that this is a static method though... but not
your problem :).

+}
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8