[ignition] Refactor array iterator to separate out access

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/interpreter/bytecode-decoder.h"
-#include "src/interpreter/interpreter-intrinsics.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),
-      operand_scale_(OperandScale::kSingle),
-      prefix_offset_(0) {
-  UpdateOperandScale();
-}
+    : BytecodeArrayAccessor(bytecode_array, 0) {}
 
 void BytecodeArrayIterator::Advance() {
-  bytecode_offset_ += current_bytecode_size();
-  UpdateOperandScale();
-}
-
-void BytecodeArrayIterator::UpdateOperandScale() {
-  if (!done()) {
-    uint8_t current_byte = bytecode_array()->get(bytecode_offset_);
-    Bytecode current_bytecode = Bytecodes::FromByte(current_byte);
-    if (Bytecodes::IsPrefixScalingBytecode(current_bytecode)) {
-      operand_scale_ =
-          Bytecodes::PrefixBytecodeToOperandScale(current_bytecode);
-      prefix_offset_ = 1;
-    } else {
-      operand_scale_ = OperandScale::kSingle;
-      prefix_offset_ = 0;
-    }
-  }
+  SetOffset(current_offset() + current_bytecode_size());
 }
 
 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_ + current_prefix_offset());
-  Bytecode current_bytecode = Bytecodes::FromByte(current_byte);
-  DCHECK(!Bytecodes::IsPrefixScalingBytecode(current_bytecode));
-  return current_bytecode;
-}
-
-int BytecodeArrayIterator::current_bytecode_size() const {
-  return current_prefix_offset() +
-         Bytecodes::Size(current_bytecode(), current_operand_scale());
-}
-
-uint32_t BytecodeArrayIterator::GetUnsignedOperand(
-    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));
-  DCHECK(Bytecodes::IsUnsignedOperandType(operand_type));
-  const uint8_t* operand_start =
-      bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
-      current_prefix_offset() +
-      Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
-                                  current_operand_scale());
-  return BytecodeDecoder::DecodeUnsignedOperand(operand_start, operand_type,
-                                                current_operand_scale());
-}
-
-int32_t BytecodeArrayIterator::GetSignedOperand(
-    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));
-  DCHECK(!Bytecodes::IsUnsignedOperandType(operand_type));
-  const uint8_t* operand_start =
-      bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
-      current_prefix_offset() +
-      Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
-                                  current_operand_scale());
-  return BytecodeDecoder::DecodeSignedOperand(operand_start, operand_type,
-                                              current_operand_scale());
-}
-
-uint32_t BytecodeArrayIterator::GetFlagOperand(int operand_index) const {
-  DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
-            OperandType::kFlag8);
-  return GetUnsignedOperand(operand_index, OperandType::kFlag8);
-}
-
-uint32_t BytecodeArrayIterator::GetUnsignedImmediateOperand(
-    int operand_index) const {
-  DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
-            OperandType::kUImm);
-  return GetUnsignedOperand(operand_index, OperandType::kUImm);
-}
-
-int32_t BytecodeArrayIterator::GetImmediateOperand(int operand_index) const {
-  DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
-            OperandType::kImm);
-  return GetSignedOperand(operand_index, OperandType::kImm);
-}
-
-uint32_t BytecodeArrayIterator::GetRegisterCountOperand(
-    int operand_index) const {
-  DCHECK_EQ(Bytecodes::GetOperandType(current_bytecode(), operand_index),
-            OperandType::kRegCount);
-  return GetUnsignedOperand(operand_index, OperandType::kRegCount);
-}
-
-uint32_t BytecodeArrayIterator::GetIndexOperand(int operand_index) const {
-  OperandType operand_type =
-      Bytecodes::GetOperandType(current_bytecode(), operand_index);
-  DCHECK_EQ(operand_type, OperandType::kIdx);
-  return GetUnsignedOperand(operand_index, operand_type);
-}
-
-Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
-  OperandType operand_type =
-      Bytecodes::GetOperandType(current_bytecode(), operand_index);
-  const uint8_t* operand_start =
-      bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
-      current_prefix_offset() +
-      Bytecodes::GetOperandOffset(current_bytecode(), operand_index,
-                                  current_operand_scale());
-  return BytecodeDecoder::DecodeRegisterOperand(operand_start, operand_type,
-                                                current_operand_scale());
-}
-
-int BytecodeArrayIterator::GetRegisterOperandRange(int operand_index) const {
-  DCHECK_LE(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
-  const OperandType* operand_types =
-      Bytecodes::GetOperandTypes(current_bytecode());
-  OperandType operand_type = operand_types[operand_index];
-  DCHECK(Bytecodes::IsRegisterOperandType(operand_type));
-  if (operand_type == OperandType::kRegList) {
-    return GetRegisterCountOperand(operand_index + 1);
-  } else {
-    return Bytecodes::GetNumberOfRegistersRepresentedBy(operand_type);
-  }
-}
-
-Runtime::FunctionId BytecodeArrayIterator::GetRuntimeIdOperand(
-    int operand_index) const {
-  OperandType operand_type =
-      Bytecodes::GetOperandType(current_bytecode(), operand_index);
-  DCHECK(operand_type == OperandType::kRuntimeId);
-  uint32_t raw_id = GetUnsignedOperand(operand_index, operand_type);
-  return static_cast<Runtime::FunctionId>(raw_id);
-}
-
-Runtime::FunctionId BytecodeArrayIterator::GetIntrinsicIdOperand(
-    int operand_index) const {
-  OperandType operand_type =
-      Bytecodes::GetOperandType(current_bytecode(), operand_index);
-  DCHECK(operand_type == OperandType::kIntrinsicId);
-  uint32_t raw_id = GetUnsignedOperand(operand_index, operand_type);
-  return IntrinsicsHelper::ToRuntimeId(
-      static_cast<IntrinsicsHelper::IntrinsicId>(raw_id));
-}
-
-Handle<Object> BytecodeArrayIterator::GetConstantForIndexOperand(
-    int operand_index) const {
-  return FixedArray::get(bytecode_array()->constant_pool(),
-                         GetIndexOperand(operand_index),
-                         bytecode_array()->GetIsolate());
-}
-
-
-int BytecodeArrayIterator::GetJumpTargetOffset() const {
-  Bytecode bytecode = current_bytecode();
-  if (interpreter::Bytecodes::IsJumpImmediate(bytecode)) {
-    int relative_offset = GetImmediateOperand(0);
-    return current_offset() + relative_offset + current_prefix_offset();
-  } else if (interpreter::Bytecodes::IsJumpConstant(bytecode)) {
-    Smi* smi = Smi::cast(*GetConstantForIndexOperand(0));
-    return current_offset() + smi->value() + current_prefix_offset();
-  } else {
-    UNREACHABLE();
-    return kMinInt;
-  }
+  return current_offset() >= bytecode_array()->length();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8