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/*
* Copyright (C) 2013, 2014 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
#if ENABLE(CSS_SELECTOR_JIT)
#include "RegisterAllocator.h"
#include <JavaScriptCore/MacroAssembler.h>
#include <limits>
namespace WebCore {
class StackAllocator {
public:
class StackReference {
public:
StackReference()
: m_offsetFromTop(std::numeric_limits<unsigned>::max())
{ }
explicit StackReference(unsigned offset)
: m_offsetFromTop(offset)
{ }
operator unsigned() const { return m_offsetFromTop; }
bool isValid() const { return m_offsetFromTop != std::numeric_limits<unsigned>::max(); }
private:
unsigned m_offsetFromTop;
};
typedef Vector<StackReference, maximumRegisterCount> StackReferenceVector;
StackAllocator(JSC::MacroAssembler& assembler)
: m_assembler(assembler)
, m_offsetFromTop(0)
, m_hasFunctionCallPadding(false)
{
}
StackReference stackTop()
{
return StackReference(m_offsetFromTop + stackUnitInBytes());
}
~StackAllocator()
{
RELEASE_ASSERT(!m_offsetFromTop);
RELEASE_ASSERT(!m_hasFunctionCallPadding);
}
StackReference allocateUninitialized()
{
return allocateUninitialized(1)[0];
}
StackReferenceVector allocateUninitialized(unsigned count)
{
RELEASE_ASSERT(!m_hasFunctionCallPadding);
StackReferenceVector stackReferences;
unsigned oldOffsetFromTop = m_offsetFromTop;
#if CPU(ARM64)
for (unsigned i = 0; i < count - 1; i += 2) {
m_offsetFromTop += stackUnitInBytes();
stackReferences.append(StackReference(m_offsetFromTop - stackUnitInBytes() / 2));
stackReferences.append(StackReference(m_offsetFromTop));
}
if (count % 2) {
m_offsetFromTop += stackUnitInBytes();
stackReferences.append(StackReference(m_offsetFromTop));
}
#else
for (unsigned i = 0; i < count; ++i) {
m_offsetFromTop += stackUnitInBytes();
stackReferences.append(StackReference(m_offsetFromTop));
}
#endif
m_assembler.addPtrNoFlags(JSC::MacroAssembler::TrustedImm32(-(m_offsetFromTop - oldOffsetFromTop)), JSC::MacroAssembler::stackPointerRegister);
return stackReferences;
}
template<size_t inlineCapacity, typename OverflowHandler>
StackReferenceVector push(const Vector<JSC::MacroAssembler::RegisterID, inlineCapacity, OverflowHandler>& registerIDs)
{
RELEASE_ASSERT(!m_hasFunctionCallPadding);
StackReferenceVector stackReferences;
if (registerIDs.isEmpty())
return stackReferences;
#if CPU(ARM64)
unsigned pushRegisterCount = registerIDs.size();
for (unsigned i = 0; i < pushRegisterCount - 1; i += 2) {
m_assembler.pushPair(registerIDs[i + 1], registerIDs[i]);
m_offsetFromTop += stackUnitInBytes();
stackReferences.append(StackReference(m_offsetFromTop - stackUnitInBytes() / 2));
stackReferences.append(StackReference(m_offsetFromTop));
}
if (pushRegisterCount % 2)
stackReferences.append(push(registerIDs[pushRegisterCount - 1]));
#else
for (auto registerID : registerIDs)
stackReferences.append(push(registerID));
#endif
return stackReferences;
}
StackReference push(JSC::MacroAssembler::RegisterID registerID)
{
RELEASE_ASSERT(!m_hasFunctionCallPadding);
m_assembler.pushToSave(registerID);
m_offsetFromTop += stackUnitInBytes();
return StackReference(m_offsetFromTop);
}
template<size_t inlineCapacity, typename OverflowHandler>
void pop(const StackReferenceVector& stackReferences, const Vector<JSC::MacroAssembler::RegisterID, inlineCapacity, OverflowHandler>& registerIDs)
{
RELEASE_ASSERT(!m_hasFunctionCallPadding);
unsigned popRegisterCount = registerIDs.size();
RELEASE_ASSERT(stackReferences.size() == popRegisterCount);
#if CPU(ARM64)
ASSERT(m_offsetFromTop >= stackUnitInBytes() * ((popRegisterCount + 1) / 2));
unsigned popRegisterCountOdd = popRegisterCount % 2;
if (popRegisterCountOdd)
pop(stackReferences[popRegisterCount - 1], registerIDs[popRegisterCount - 1]);
for (unsigned i = popRegisterCount - popRegisterCountOdd; i > 0; i -= 2) {
RELEASE_ASSERT(stackReferences[i - 1] == m_offsetFromTop);
RELEASE_ASSERT(stackReferences[i - 2] == m_offsetFromTop - stackUnitInBytes() / 2);
RELEASE_ASSERT(m_offsetFromTop >= stackUnitInBytes());
m_offsetFromTop -= stackUnitInBytes();
m_assembler.popPair(registerIDs[i - 1], registerIDs[i - 2]);
}
#else
ASSERT(m_offsetFromTop >= stackUnitInBytes() * popRegisterCount);
for (unsigned i = popRegisterCount; i > 0; --i)
pop(stackReferences[i - 1], registerIDs[i - 1]);
#endif
}
void pop(StackReference stackReference, JSC::MacroAssembler::RegisterID registerID)
{
RELEASE_ASSERT(stackReference == m_offsetFromTop);
RELEASE_ASSERT(!m_hasFunctionCallPadding);
RELEASE_ASSERT(m_offsetFromTop >= stackUnitInBytes());
m_offsetFromTop -= stackUnitInBytes();
m_assembler.popToRestore(registerID);
}
void popAndDiscardUpTo(StackReference stackReference)
{
unsigned positionBeforeStackReference = stackReference - stackUnitInBytes();
RELEASE_ASSERT(positionBeforeStackReference < m_offsetFromTop);
unsigned stackDelta = m_offsetFromTop - positionBeforeStackReference;
m_assembler.addPtr(JSC::MacroAssembler::TrustedImm32(stackDelta), JSC::MacroAssembler::stackPointerRegister);
m_offsetFromTop -= stackDelta;
}
void alignStackPreFunctionCall()
{
#if CPU(X86_64)
RELEASE_ASSERT(!m_hasFunctionCallPadding);
unsigned topAlignment = stackUnitInBytes();
if ((topAlignment + m_offsetFromTop) % 16) {
m_hasFunctionCallPadding = true;
m_assembler.addPtrNoFlags(JSC::MacroAssembler::TrustedImm32(-stackUnitInBytes()), JSC::MacroAssembler::stackPointerRegister);
}
#endif
}
void unalignStackPostFunctionCall()
{
#if CPU(X86_64)
if (m_hasFunctionCallPadding) {
m_assembler.addPtrNoFlags(JSC::MacroAssembler::TrustedImm32(stackUnitInBytes()), JSC::MacroAssembler::stackPointerRegister);
m_hasFunctionCallPadding = false;
}
#endif
}
void merge(StackAllocator&& stackA, StackAllocator&& stackB)
{
RELEASE_ASSERT(stackA.m_offsetFromTop == stackB.m_offsetFromTop);
RELEASE_ASSERT(stackA.m_hasFunctionCallPadding == stackB.m_hasFunctionCallPadding);
ASSERT(&stackA.m_assembler == &stackB.m_assembler);
ASSERT(&m_assembler == &stackB.m_assembler);
m_offsetFromTop = stackA.m_offsetFromTop;
m_hasFunctionCallPadding = stackA.m_hasFunctionCallPadding;
stackA.reset();
stackB.reset();
}
void merge(StackAllocator&& stackA, StackAllocator&& stackB, StackAllocator&& stackC)
{
RELEASE_ASSERT(stackA.m_offsetFromTop == stackB.m_offsetFromTop);
RELEASE_ASSERT(stackA.m_offsetFromTop == stackC.m_offsetFromTop);
RELEASE_ASSERT(stackA.m_hasFunctionCallPadding == stackB.m_hasFunctionCallPadding);
RELEASE_ASSERT(stackA.m_hasFunctionCallPadding == stackC.m_hasFunctionCallPadding);
ASSERT(&stackA.m_assembler == &stackB.m_assembler);
ASSERT(&stackA.m_assembler == &stackC.m_assembler);
ASSERT(&m_assembler == &stackB.m_assembler);
m_offsetFromTop = stackA.m_offsetFromTop;
m_hasFunctionCallPadding = stackA.m_hasFunctionCallPadding;
stackA.reset();
stackB.reset();
stackC.reset();
}
JSC::MacroAssembler::Address addressOf(StackReference stackReference)
{
return JSC::MacroAssembler::Address(JSC::MacroAssembler::stackPointerRegister, offsetToStackReference(stackReference));
}
StackAllocator& operator=(const StackAllocator& other)
{
RELEASE_ASSERT(&m_assembler == &other.m_assembler);
m_offsetFromTop = other.m_offsetFromTop;
m_hasFunctionCallPadding = other.m_hasFunctionCallPadding;
return *this;
}
private:
static unsigned stackUnitInBytes()
{
return JSC::MacroAssembler::pushToSaveByteOffset();
}
unsigned offsetToStackReference(StackReference stackReference)
{
RELEASE_ASSERT(m_offsetFromTop >= stackReference);
return m_offsetFromTop - stackReference;
}
void reset()
{
m_offsetFromTop = 0;
m_hasFunctionCallPadding = false;
}
JSC::MacroAssembler& m_assembler;
unsigned m_offsetFromTop;
bool m_hasFunctionCallPadding;
};
} // namespace WebCore
#endif // ENABLE(CSS_SELECTOR_JIT)