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// 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-decoder.h"
#include <iomanip>
#include "src/contexts.h"
#include "src/interpreter/interpreter-intrinsics.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
namespace interpreter {
// static
Register BytecodeDecoder::DecodeRegisterOperand(Address operand_start,
OperandType operand_type,
OperandScale operand_scale) {
DCHECK(Bytecodes::IsRegisterOperandType(operand_type));
int32_t operand =
DecodeSignedOperand(operand_start, operand_type, operand_scale);
return Register::FromOperand(operand);
}
// static
RegisterList BytecodeDecoder::DecodeRegisterListOperand(
Address operand_start, uint32_t count, OperandType operand_type,
OperandScale operand_scale) {
Register first_reg =
DecodeRegisterOperand(operand_start, operand_type, operand_scale);
return RegisterList(first_reg.index(), static_cast<int>(count));
}
// static
int32_t BytecodeDecoder::DecodeSignedOperand(Address operand_start,
OperandType operand_type,
OperandScale operand_scale) {
DCHECK(!Bytecodes::IsUnsignedOperandType(operand_type));
switch (Bytecodes::SizeOfOperand(operand_type, operand_scale)) {
case OperandSize::kByte:
return *reinterpret_cast<const int8_t*>(operand_start);
case OperandSize::kShort:
return static_cast<int16_t>(ReadUnalignedUInt16(operand_start));
case OperandSize::kQuad:
return static_cast<int32_t>(ReadUnalignedUInt32(operand_start));
case OperandSize::kNone:
UNREACHABLE();
}
return 0;
}
// static
uint32_t BytecodeDecoder::DecodeUnsignedOperand(Address operand_start,
OperandType operand_type,
OperandScale operand_scale) {
DCHECK(Bytecodes::IsUnsignedOperandType(operand_type));
switch (Bytecodes::SizeOfOperand(operand_type, operand_scale)) {
case OperandSize::kByte:
return *reinterpret_cast<const uint8_t*>(operand_start);
case OperandSize::kShort:
return ReadUnalignedUInt16(operand_start);
case OperandSize::kQuad:
return ReadUnalignedUInt32(operand_start);
case OperandSize::kNone:
UNREACHABLE();
}
return 0;
}
namespace {
const char* NameForRuntimeId(uint32_t idx) {
switch (idx) {
#define CASE(name, nargs, ressize) \
case Runtime::k##name: \
return #name; \
case Runtime::kInline##name: \
return "_" #name;
FOR_EACH_INTRINSIC(CASE)
#undef CASE
default:
UNREACHABLE();
}
}
const char* NameForNativeContextIndex(uint32_t idx) {
switch (idx) {
#define CASE(index_name, type, name) \
case Context::index_name: \
return #name;
NATIVE_CONTEXT_FIELDS(CASE)
#undef CASE
default:
UNREACHABLE();
}
}
} // anonymous namespace
// static
std::ostream& BytecodeDecoder::Decode(std::ostream& os,
const uint8_t* bytecode_start,
int parameter_count) {
Bytecode bytecode = Bytecodes::FromByte(bytecode_start[0]);
int prefix_offset = 0;
OperandScale operand_scale = OperandScale::kSingle;
if (Bytecodes::IsPrefixScalingBytecode(bytecode)) {
prefix_offset = 1;
operand_scale = Bytecodes::PrefixBytecodeToOperandScale(bytecode);
bytecode = Bytecodes::FromByte(bytecode_start[1]);
}
// Prepare to print bytecode and operands as hex digits.
std::ios saved_format(nullptr);
saved_format.copyfmt(saved_format);
os.fill('0');
os.flags(std::ios::hex);
int bytecode_size = Bytecodes::Size(bytecode, operand_scale);
for (int i = 0; i < prefix_offset + bytecode_size; i++) {
os << std::setw(2) << static_cast<uint32_t>(bytecode_start[i]) << ' ';
}
os.copyfmt(saved_format);
const int kBytecodeColumnSize = 6;
for (int i = prefix_offset + bytecode_size; i < kBytecodeColumnSize; i++) {
os << " ";
}
os << Bytecodes::ToString(bytecode, operand_scale) << " ";
// Operands for the debug break are from the original instruction.
if (Bytecodes::IsDebugBreak(bytecode)) return os;
int number_of_operands = Bytecodes::NumberOfOperands(bytecode);
for (int i = 0; i < number_of_operands; i++) {
OperandType op_type = Bytecodes::GetOperandType(bytecode, i);
int operand_offset =
Bytecodes::GetOperandOffset(bytecode, i, operand_scale);
Address operand_start = reinterpret_cast<Address>(
&bytecode_start[prefix_offset + operand_offset]);
switch (op_type) {
case interpreter::OperandType::kIdx:
case interpreter::OperandType::kUImm:
os << "["
<< DecodeUnsignedOperand(operand_start, op_type, operand_scale)
<< "]";
break;
case interpreter::OperandType::kIntrinsicId: {
auto id = static_cast<IntrinsicsHelper::IntrinsicId>(
DecodeUnsignedOperand(operand_start, op_type, operand_scale));
os << "[" << NameForRuntimeId(IntrinsicsHelper::ToRuntimeId(id)) << "]";
break;
}
case interpreter::OperandType::kNativeContextIndex: {
auto id = DecodeUnsignedOperand(operand_start, op_type, operand_scale);
os << "[" << NameForNativeContextIndex(id) << "]";
break;
}
case interpreter::OperandType::kRuntimeId:
os << "[" << NameForRuntimeId(DecodeUnsignedOperand(
operand_start, op_type, operand_scale))
<< "]";
break;
case interpreter::OperandType::kImm:
os << "[" << DecodeSignedOperand(operand_start, op_type, operand_scale)
<< "]";
break;
case interpreter::OperandType::kFlag8:
os << "#"
<< DecodeUnsignedOperand(operand_start, op_type, operand_scale);
break;
case interpreter::OperandType::kReg:
case interpreter::OperandType::kRegOut: {
Register reg =
DecodeRegisterOperand(operand_start, op_type, operand_scale);
os << reg.ToString(parameter_count);
break;
}
case interpreter::OperandType::kRegOutTriple: {
RegisterList reg_list =
DecodeRegisterListOperand(operand_start, 3, op_type, operand_scale);
os << reg_list.first_register().ToString(parameter_count) << "-"
<< reg_list.last_register().ToString(parameter_count);
break;
}
case interpreter::OperandType::kRegOutPair:
case interpreter::OperandType::kRegPair: {
RegisterList reg_list =
DecodeRegisterListOperand(operand_start, 2, op_type, operand_scale);
os << reg_list.first_register().ToString(parameter_count) << "-"
<< reg_list.last_register().ToString(parameter_count);
break;
}
case interpreter::OperandType::kRegOutList:
case interpreter::OperandType::kRegList: {
DCHECK_LT(i, number_of_operands - 1);
DCHECK_EQ(Bytecodes::GetOperandType(bytecode, i + 1),
OperandType::kRegCount);
int reg_count_offset =
Bytecodes::GetOperandOffset(bytecode, i + 1, operand_scale);
Address reg_count_operand = reinterpret_cast<Address>(
&bytecode_start[prefix_offset + reg_count_offset]);
uint32_t count = DecodeUnsignedOperand(
reg_count_operand, OperandType::kRegCount, operand_scale);
RegisterList reg_list = DecodeRegisterListOperand(
operand_start, count, op_type, operand_scale);
os << reg_list.first_register().ToString(parameter_count) << "-"
<< reg_list.last_register().ToString(parameter_count);
i++; // Skip kRegCount.
break;
}
case interpreter::OperandType::kNone:
case interpreter::OperandType::kRegCount: // Dealt with in kRegList.
UNREACHABLE();
break;
}
if (i != number_of_operands - 1) {
os << ", ";
}
}
return os;
}
} // namespace interpreter
} // namespace internal
} // namespace v8
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