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/*
* Copyright (C) 2016 Yusuke Suzuki <utatane.tea@gmail.com>
* Copyright (C) 2016-2017 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.
*/
#include "config.h"
#include "BytecodeRewriter.h"
#include "JSCJSValueInlines.h"
#include "PreciseJumpTargetsInlines.h"
#include <wtf/BubbleSort.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
namespace JSC {
void BytecodeRewriter::applyModification()
{
for (size_t insertionIndex = m_insertions.size(); insertionIndex--;) {
Insertion& insertion = m_insertions[insertionIndex];
if (insertion.type == Insertion::Type::Remove)
m_writer.m_instructions.remove(insertion.index.bytecodeOffset, insertion.length());
else {
if (insertion.includeBranch == IncludeBranch::Yes) {
int finalOffset = insertion.index.bytecodeOffset + calculateDifference(m_insertions.begin(), m_insertions.begin() + insertionIndex);
adjustJumpTargetsInFragment(finalOffset, insertion);
}
m_writer.m_instructions.insertVector(insertion.index.bytecodeOffset, insertion.instructions.m_instructions);
}
}
m_insertions.clear();
}
void BytecodeRewriter::execute()
{
WTF::bubbleSort(m_insertions.begin(), m_insertions.end(), [] (const Insertion& lhs, const Insertion& rhs) {
return lhs.index < rhs.index;
});
m_codeBlock->applyModification(*this, m_writer);
}
void BytecodeRewriter::adjustJumpTargetsInFragment(unsigned finalOffset, Insertion& insertion)
{
for (auto& instruction : insertion.instructions) {
if (isBranch(instruction->opcodeID())) {
unsigned bytecodeOffset = finalOffset + instruction.offset();
updateStoredJumpTargetsForInstruction(m_codeBlock, finalOffset, instruction, [&](int32_t label) {
int absoluteOffset = adjustAbsoluteOffset(label);
return absoluteOffset - static_cast<int>(bytecodeOffset);
});
}
}
}
void BytecodeRewriter::insertImpl(InsertionPoint insertionPoint, IncludeBranch includeBranch, JSInstructionStreamWriter&& writer)
{
ASSERT(insertionPoint.position == Position::Before || insertionPoint.position == Position::After);
m_insertions.append(Insertion {
insertionPoint,
Insertion::Type::Insert,
includeBranch,
0,
WTFMove(writer)
});
}
int32_t BytecodeRewriter::adjustJumpTarget(InsertionPoint startPoint, InsertionPoint jumpTargetPoint)
{
if (startPoint < jumpTargetPoint) {
int jumpTarget = jumpTargetPoint.bytecodeOffset;
auto start = std::lower_bound(m_insertions.begin(), m_insertions.end(), startPoint, [&] (const Insertion& insertion, InsertionPoint startPoint) {
return insertion.index < startPoint;
});
if (start != m_insertions.end()) {
auto end = std::lower_bound(m_insertions.begin(), m_insertions.end(), jumpTargetPoint, [&] (const Insertion& insertion, InsertionPoint jumpTargetPoint) {
return insertion.index < jumpTargetPoint;
});
jumpTarget += calculateDifference(start, end);
}
return jumpTarget - startPoint.bytecodeOffset;
}
if (startPoint == jumpTargetPoint)
return 0;
return -adjustJumpTarget(jumpTargetPoint, startPoint);
}
// FIXME: unit test the logic in this method
// https://bugs.webkit.org/show_bug.cgi?id=190950
void BytecodeRewriter::adjustJumpTargets()
{
auto currentInsertion = m_insertions.begin();
auto outOfLineJumpTargets = m_codeBlock->replaceOutOfLineJumpTargets();
int offset = 0;
for (JSInstructionStream::Offset i = 0; i < m_writer.size();) {
int before = 0;
int after = 0;
int remove = 0;
while (currentInsertion != m_insertions.end() && static_cast<JSInstructionStream::Offset>(currentInsertion->index.bytecodeOffset) == i) {
auto size = currentInsertion->length();
if (currentInsertion->type == Insertion::Type::Remove)
remove += size;
else if (currentInsertion->index.position == Position::Before)
before += size;
else if (currentInsertion->index.position == Position::After)
after += size;
++currentInsertion;
}
offset += before;
if (!remove) {
auto instruction = m_writer.ref(i);
updateStoredJumpTargetsForInstruction(m_codeBlock, offset, instruction, [&](int32_t relativeOffset) {
return adjustJumpTarget(instruction.offset(), instruction.offset() + relativeOffset);
}, outOfLineJumpTargets);
i += instruction->size();
} else {
offset -= remove;
i += remove;
}
offset += after;
}
}
} // namespace JSC
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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