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/*
* Copyright (C) 2016-2018 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. ``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 "ArithProfile.h"
#include "CCallHelpers.h"
#include "JITAddGenerator.h"
#include "JITMathICInlineResult.h"
#include "JITMulGenerator.h"
#include "JITNegGenerator.h"
#include "JITSubGenerator.h"
#include "LinkBuffer.h"
#include "Repatch.h"
namespace JSC {
class LinkBuffer;
struct MathICGenerationState {
MacroAssembler::Label fastPathStart;
MacroAssembler::Label fastPathEnd;
MacroAssembler::Label slowPathStart;
MacroAssembler::Call slowPathCall;
MacroAssembler::JumpList slowPathJumps;
bool shouldSlowPathRepatch;
};
#define ENABLE_MATH_IC_STATS 0
template <typename GeneratorType, bool(*isProfileEmpty)(ArithProfile&)>
class JITMathIC {
WTF_MAKE_FAST_ALLOCATED;
public:
JITMathIC(ArithProfile* arithProfile)
: m_arithProfile(arithProfile)
{
}
CodeLocationLabel<JSInternalPtrTag> doneLocation() { return m_inlineEnd; }
CodeLocationCall<JSInternalPtrTag> slowPathCallLocation() { return m_slowPathCallLocation; }
CodeLocationLabel<JSInternalPtrTag> slowPathStartLocation() { return m_slowPathStartLocation; }
bool generateInline(CCallHelpers& jit, MathICGenerationState& state, bool shouldEmitProfiling = true)
{
state.fastPathStart = jit.label();
size_t startSize = jit.m_assembler.buffer().codeSize();
if (m_arithProfile) {
if (isProfileEmpty(*m_arithProfile)) {
// It looks like the MathIC has yet to execute. We don't want to emit code in this
// case for a couple reasons. First, the operation may never execute, so if we don't emit
// code, it's a win. Second, if the operation does execute, we can emit better code
// once we have an idea about the types.
state.slowPathJumps.append(jit.patchableJump());
size_t inlineSize = jit.m_assembler.buffer().codeSize() - startSize;
ASSERT_UNUSED(inlineSize, static_cast<ptrdiff_t>(inlineSize) <= MacroAssembler::patchableJumpSize());
state.shouldSlowPathRepatch = true;
state.fastPathEnd = jit.label();
ASSERT(!m_generateFastPathOnRepatch); // We should have gathered some observed type info about the types before trying to regenerate again.
m_generateFastPathOnRepatch = true;
return true;
}
}
JITMathICInlineResult result = m_generator.generateInline(jit, state, m_arithProfile);
switch (result) {
case JITMathICInlineResult::GeneratedFastPath: {
size_t inlineSize = jit.m_assembler.buffer().codeSize() - startSize;
if (static_cast<ptrdiff_t>(inlineSize) < MacroAssembler::patchableJumpSize()) {
size_t nopsToEmitInBytes = MacroAssembler::patchableJumpSize() - inlineSize;
jit.emitNops(nopsToEmitInBytes);
}
state.shouldSlowPathRepatch = true;
state.fastPathEnd = jit.label();
return true;
}
case JITMathICInlineResult::GenerateFullSnippet: {
MacroAssembler::JumpList endJumpList;
bool result = m_generator.generateFastPath(jit, endJumpList, state.slowPathJumps, m_arithProfile, shouldEmitProfiling);
if (result) {
state.fastPathEnd = jit.label();
state.shouldSlowPathRepatch = false;
endJumpList.link(&jit);
return true;
}
return false;
}
case JITMathICInlineResult::DontGenerate: {
return false;
}
default:
ASSERT_NOT_REACHED();
}
return false;
}
void generateOutOfLine(CodeBlock* codeBlock, FunctionPtr<CFunctionPtrTag> callReplacement)
{
auto linkJumpToOutOfLineSnippet = [&] () {
CCallHelpers jit(codeBlock);
auto jump = jit.jump();
// We don't need a nop sled here because nobody should be jumping into the middle of an IC.
bool needsBranchCompaction = false;
RELEASE_ASSERT(jit.m_assembler.buffer().codeSize() <= static_cast<size_t>(MacroAssembler::differenceBetweenCodePtr(m_inlineStart, m_inlineEnd)));
LinkBuffer linkBuffer(jit, m_inlineStart, jit.m_assembler.buffer().codeSize(), JITCompilationMustSucceed, needsBranchCompaction);
RELEASE_ASSERT(linkBuffer.isValid());
linkBuffer.link(jump, CodeLocationLabel<JITStubRoutinePtrTag>(m_code.code()));
FINALIZE_CODE(linkBuffer, NoPtrTag, "JITMathIC: linking constant jump to out of line stub");
};
auto replaceCall = [&] () {
#if COMPILER(MSVC) && !COMPILER(CLANG)
ftlThunkAwareRepatchCall(codeBlock, slowPathCallLocation().retagged<JSInternalPtrTag>(), callReplacement);
#else
ftlThunkAwareRepatchCall(codeBlock, slowPathCallLocation().template retagged<JSInternalPtrTag>(), callReplacement);
#endif
};
bool shouldEmitProfiling = !JITCode::isOptimizingJIT(codeBlock->jitType());
if (m_generateFastPathOnRepatch) {
CCallHelpers jit(codeBlock);
MathICGenerationState generationState;
bool generatedInline = generateInline(jit, generationState, shouldEmitProfiling);
// We no longer want to try to regenerate the fast path.
m_generateFastPathOnRepatch = false;
if (generatedInline) {
auto jumpToDone = jit.jump();
LinkBuffer linkBuffer(jit, codeBlock, JITCompilationCanFail);
if (!linkBuffer.didFailToAllocate()) {
linkBuffer.link(generationState.slowPathJumps, slowPathStartLocation());
linkBuffer.link(jumpToDone, doneLocation());
m_code = FINALIZE_CODE_FOR(
codeBlock, linkBuffer, JITStubRoutinePtrTag, "JITMathIC: generating out of line fast IC snippet");
if (!generationState.shouldSlowPathRepatch) {
// We won't need to regenerate, so we can wire the slow path call
// to a non repatching variant.
replaceCall();
}
linkJumpToOutOfLineSnippet();
return;
}
}
// We weren't able to generate an out of line fast path.
// We just generate the snippet in its full generality.
}
// We rewire to the alternate regardless of whether or not we can allocate the out of line path
// because if we fail allocating the out of line path, we don't want to waste time trying to
// allocate it in the future.
replaceCall();
{
CCallHelpers jit(codeBlock);
MacroAssembler::JumpList endJumpList;
MacroAssembler::JumpList slowPathJumpList;
bool emittedFastPath = m_generator.generateFastPath(jit, endJumpList, slowPathJumpList, m_arithProfile, shouldEmitProfiling);
if (!emittedFastPath)
return;
endJumpList.append(jit.jump());
LinkBuffer linkBuffer(jit, codeBlock, JITCompilationCanFail);
if (linkBuffer.didFailToAllocate())
return;
linkBuffer.link(endJumpList, doneLocation());
linkBuffer.link(slowPathJumpList, slowPathStartLocation());
m_code = FINALIZE_CODE_FOR(
codeBlock, linkBuffer, JITStubRoutinePtrTag, "JITMathIC: generating out of line IC snippet");
}
linkJumpToOutOfLineSnippet();
}
void finalizeInlineCode(const MathICGenerationState& state, LinkBuffer& linkBuffer)
{
CodeLocationLabel<JSInternalPtrTag> start = linkBuffer.locationOf<JSInternalPtrTag>(state.fastPathStart);
m_inlineStart = start;
m_inlineEnd = linkBuffer.locationOf<JSInternalPtrTag>(state.fastPathEnd);
ASSERT(m_inlineEnd.untaggedExecutableAddress() > m_inlineStart.untaggedExecutableAddress());
m_slowPathCallLocation = linkBuffer.locationOf<JSInternalPtrTag>(state.slowPathCall);
m_slowPathStartLocation = linkBuffer.locationOf<JSInternalPtrTag>(state.slowPathStart);
}
ArithProfile* arithProfile() const { return m_arithProfile; }
#if ENABLE(MATH_IC_STATS)
size_t m_generatedCodeSize { 0 };
size_t codeSize() const
{
size_t result = m_generatedCodeSize;
if (m_code)
result += m_code.size();
return result;
}
#endif
ArithProfile* m_arithProfile;
MacroAssemblerCodeRef<JITStubRoutinePtrTag> m_code;
CodeLocationLabel<JSInternalPtrTag> m_inlineStart;
CodeLocationLabel<JSInternalPtrTag> m_inlineEnd;
CodeLocationLabel<JSInternalPtrTag> m_slowPathCallLocation;
CodeLocationLabel<JSInternalPtrTag> m_slowPathStartLocation;
bool m_generateFastPathOnRepatch { false };
GeneratorType m_generator;
};
inline bool isBinaryProfileEmpty(ArithProfile& arithProfile)
{
return arithProfile.lhsObservedType().isEmpty() || arithProfile.rhsObservedType().isEmpty();
}
template <typename GeneratorType>
class JITBinaryMathIC : public JITMathIC<GeneratorType, isBinaryProfileEmpty> {
public:
JITBinaryMathIC(ArithProfile* arithProfile)
: JITMathIC<GeneratorType, isBinaryProfileEmpty>(arithProfile)
{
}
};
typedef JITBinaryMathIC<JITAddGenerator> JITAddIC;
typedef JITBinaryMathIC<JITMulGenerator> JITMulIC;
typedef JITBinaryMathIC<JITSubGenerator> JITSubIC;
inline bool isUnaryProfileEmpty(ArithProfile& arithProfile)
{
return arithProfile.lhsObservedType().isEmpty();
}
template <typename GeneratorType>
class JITUnaryMathIC : public JITMathIC<GeneratorType, isUnaryProfileEmpty> {
public:
JITUnaryMathIC(ArithProfile* arithProfile)
: JITMathIC<GeneratorType, isUnaryProfileEmpty>(arithProfile)
{
}
};
typedef JITUnaryMathIC<JITNegGenerator> JITNegIC;
} // namespace JSC
#endif // ENABLE(JIT)