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/*
* Copyright (C) 2012-2021 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. ``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
* 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
#if ENABLE(JIT)
#include "FPRInfo.h"
#include "RegisterSet.h"
namespace JSC {
class AssemblyHelpers;
struct ScratchBuffer;
// This class provides a low-level register allocator for use in stubs.
class ScratchRegisterAllocator {
public:
ScratchRegisterAllocator() = default;
ScratchRegisterAllocator(const RegisterSet& usedRegisters);
~ScratchRegisterAllocator();
void lock(GPRReg);
void lock(FPRReg);
void lock(JSValueRegs);
template<typename BankInfo>
typename BankInfo::RegisterType allocateScratch();
GPRReg allocateScratchGPR();
FPRReg allocateScratchFPR();
bool didReuseRegisters() const
{
return !!m_numberOfReusedRegisters;
}
unsigned numberOfReusedRegisters() const
{
return m_numberOfReusedRegisters;
}
RegisterSet usedRegisters() const { return m_usedRegisters; }
enum class ExtraStackSpace { SpaceForCCall, NoExtraSpace };
struct PreservedState {
PreservedState()
: numberOfBytesPreserved(std::numeric_limits<unsigned>::max())
, extraStackSpaceRequirement(ExtraStackSpace::SpaceForCCall)
{ }
PreservedState(unsigned numberOfBytes, ExtraStackSpace extraStackSpace)
: numberOfBytesPreserved(numberOfBytes)
, extraStackSpaceRequirement(extraStackSpace)
{ }
explicit operator bool() const { return numberOfBytesPreserved != std::numeric_limits<unsigned>::max(); }
unsigned numberOfBytesPreserved;
ExtraStackSpace extraStackSpaceRequirement;
};
PreservedState preserveReusedRegistersByPushing(AssemblyHelpers& jit, ExtraStackSpace);
void restoreReusedRegistersByPopping(AssemblyHelpers& jit, const PreservedState&);
static unsigned preserveRegistersToStackForCall(AssemblyHelpers& jit, const RegisterSet& usedRegisters, unsigned extraPaddingInBytes);
static void restoreRegistersFromStackForCall(AssemblyHelpers& jit, const RegisterSet& usedRegisters, const RegisterSet& ignore, unsigned numberOfStackBytesUsedForRegisterPreservation, unsigned extraPaddingInBytes);
private:
RegisterSet m_usedRegisters { };
RegisterSet m_scratchRegisters { };
ScalarRegisterSet m_lockedRegisters { };
unsigned m_numberOfReusedRegisters { 0 };
};
} // namespace JSC
#endif // ENABLE(JIT)
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