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/*
* Copyright (C) 2018 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "Opcode.h"
#include "OpcodeSize.h"
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
struct JSOpcodeTraits {
using OpcodeID = ::JSC::OpcodeID;
static constexpr OpcodeID numberOfBytecodesWithCheckpoints = static_cast<OpcodeID>(NUMBER_OF_BYTECODE_WITH_CHECKPOINTS);
static constexpr OpcodeID numberOfBytecodesWithMetadata = static_cast<OpcodeID>(NUMBER_OF_BYTECODE_WITH_METADATA);
static_assert(numberOfBytecodesWithCheckpoints <= numberOfBytecodesWithMetadata);
static constexpr OpcodeID wide16 = op_wide16;
static constexpr OpcodeID wide32 = op_wide32;
static constexpr const unsigned* opcodeLengths = ::JSC::opcodeLengths;
static constexpr const ASCIILiteral* opcodeNames = ::JSC::opcodeNames;
static constexpr auto checkpointCountTable = bytecodeCheckpointCountTable;
static constexpr OpcodeSize maxOpcodeIDWidth = maxJSOpcodeIDWidth;
};
struct WasmOpcodeTraits {
using OpcodeID = WasmOpcodeID;
static constexpr OpcodeID numberOfBytecodesWithCheckpoints = static_cast<OpcodeID>(NUMBER_OF_WASM_WITH_CHECKPOINTS);
static constexpr OpcodeID numberOfBytecodesWithMetadata = static_cast<OpcodeID>(NUMBER_OF_WASM_WITH_METADATA);
static_assert(numberOfBytecodesWithCheckpoints <= numberOfBytecodesWithMetadata);
static constexpr OpcodeID wide16 = wasm_wide16;
static constexpr OpcodeID wide32 = wasm_wide32;
static constexpr const unsigned* opcodeLengths = wasmOpcodeLengths;
static constexpr const char* const* opcodeNames = wasmOpcodeNames;
static constexpr auto checkpointCountTable = wasmCheckpointCountTable;
static constexpr OpcodeSize maxOpcodeIDWidth = maxWasmOpcodeIDWidth;
};
template<typename Traits>
struct BaseInstruction {
struct Metadata { };
protected:
BaseInstruction()
{ }
private:
template<OpcodeSize Width>
class Impl {
public:
typename Traits::OpcodeID opcodeID() const { return static_cast<typename Traits::OpcodeID>(m_opcode); }
private:
typename OpcodeIDWidthBySize<Traits, Width>::opcodeType m_opcode;
};
public:
typename Traits::OpcodeID opcodeID() const
{
if (isWide32())
return wide32()->opcodeID();
if (isWide16())
return wide16()->opcodeID();
return narrow()->opcodeID();
}
const char* name() const
{
return Traits::opcodeNames[opcodeID()];
}
bool isWide16() const
{
return narrow()->opcodeID() == Traits::wide16;
}
bool isWide32() const
{
return narrow()->opcodeID() == Traits::wide32;
}
OpcodeSize width() const
{
if (isWide32())
return OpcodeSize::Wide32;
return isWide16() ? OpcodeSize::Wide16 : OpcodeSize::Narrow;
}
bool hasMetadata() const
{
return opcodeID() < Traits::numberOfBytecodesWithMetadata;
}
bool hasCheckpoints() const
{
return opcodeID() < Traits::numberOfBytecodesWithCheckpoints;
}
unsigned numberOfCheckpoints() const
{
if (!hasCheckpoints())
return 1;
return Traits::checkpointCountTable[opcodeID()];
}
int sizeShiftAmount() const
{
if (isWide32())
return 2;
if (isWide16())
return 1;
return 0;
}
OpcodeSize opcodeIDWidth() const
{
if (isWide32())
return OpcodeIDWidthBySize<Traits, OpcodeSize::Wide32>::opcodeIDSize;
if (isWide16())
return OpcodeIDWidthBySize<Traits, OpcodeSize::Wide16>::opcodeIDSize;
return OpcodeIDWidthBySize<Traits, OpcodeSize::Narrow>::opcodeIDSize;
}
unsigned opcodeIDBytes() const
{
return (unsigned) opcodeIDWidth();
}
size_t size() const
{
auto sizeShiftAmount = this->sizeShiftAmount();
size_t prefixSize = sizeShiftAmount ? 1 : 0;
size_t operandSize = static_cast<size_t>(1) << sizeShiftAmount;
size_t sizeOfBytecode = opcodeIDBytes();
return sizeOfBytecode + Traits::opcodeLengths[opcodeID()] * operandSize + prefixSize;
}
template<class T>
bool is() const
{
return opcodeID() == T::opcodeID;
}
template<class T>
T as() const
{
ASSERT((is<T>()));
return T::decode(reinterpret_cast<const uint8_t*>(this));
}
template<class T, OpcodeSize width>
T asKnownWidth() const
{
ASSERT((is<T>()));
return T(reinterpret_cast_ptr<const typename TypeBySize<width>::unsignedType*>(this + (width == OpcodeSize::Narrow ? 1 : 2)));
}
template<class T>
T* cast()
{
ASSERT((is<T>()));
return std::bit_cast<T*>(this);
}
template<class T>
const T* cast() const
{
ASSERT((is<T>()));
return reinterpret_cast<const T*>(this);
}
const Impl<OpcodeSize::Narrow>* narrow() const
{
return reinterpret_cast<const Impl<OpcodeSize::Narrow>*>(this);
}
const Impl<OpcodeSize::Wide16>* wide16() const
{
static_assert(sizeof(*this) == 1, "Pointer math");
ASSERT(isWide16());
return reinterpret_cast<const Impl<OpcodeSize::Wide16>*>(this + 1);
}
const Impl<OpcodeSize::Wide32>* wide32() const
{
static_assert(sizeof(*this) == 1, "Pointer math");
ASSERT(isWide32());
return reinterpret_cast<const Impl<OpcodeSize::Wide32>*>(this + 1);
}
};
using JSInstruction = BaseInstruction<JSOpcodeTraits>;
using WasmInstruction = BaseInstruction<WasmOpcodeTraits>;
static_assert(sizeof(JSInstruction) == 1, "So pointer math is the same as byte math");
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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