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/*
* Copyright (C) 2013-2017 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. ``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.
*/
#include "config.h"
#include "PreciseJumpTargets.h"
#include "InterpreterInlines.h"
#include "JSCInlines.h"
#include "PreciseJumpTargetsInlines.h"
namespace JSC {
template <size_t vectorSize, typename Block>
static void getJumpTargetsForInstruction(Block* codeBlock, const InstructionStream::Ref& instruction, Vector<InstructionStream::Offset, vectorSize>& out)
{
extractStoredJumpTargetsForInstruction(codeBlock, instruction, [&](int32_t relativeOffset) {
out.append(instruction.offset() + relativeOffset);
});
OpcodeID opcodeID = instruction->opcodeID();
// op_loop_hint does not have jump target stored in bytecode instructions.
if (opcodeID == op_loop_hint)
out.append(instruction.offset());
else if (opcodeID == op_enter && codeBlock->hasTailCalls() && Options::optimizeRecursiveTailCalls()) {
// We need to insert a jump after op_enter, so recursive tail calls have somewhere to jump to.
// But we only want to pay that price for functions that have at least one tail call.
out.append(instruction.next().offset());
}
}
enum class ComputePreciseJumpTargetsMode {
FollowCodeBlockClaim,
ForceCompute,
};
template<ComputePreciseJumpTargetsMode Mode, typename Block, size_t vectorSize>
void computePreciseJumpTargetsInternal(Block* codeBlock, const InstructionStream& instructions, Vector<InstructionStream::Offset, vectorSize>& out)
{
ASSERT(out.isEmpty());
// The code block has a superset of the jump targets. So if it claims to have none, we are done.
if (Mode == ComputePreciseJumpTargetsMode::FollowCodeBlockClaim && !codeBlock->numberOfJumpTargets())
return;
for (unsigned i = codeBlock->numberOfExceptionHandlers(); i--;) {
out.append(codeBlock->exceptionHandler(i).target);
out.append(codeBlock->exceptionHandler(i).start);
out.append(codeBlock->exceptionHandler(i).end);
}
for (const auto& instruction : instructions) {
getJumpTargetsForInstruction(codeBlock, instruction, out);
}
std::sort(out.begin(), out.end());
// We will have duplicates, and we must remove them.
unsigned toIndex = 0;
unsigned fromIndex = 0;
unsigned lastValue = UINT_MAX;
while (fromIndex < out.size()) {
unsigned value = out[fromIndex++];
if (value == lastValue)
continue;
out[toIndex++] = value;
lastValue = value;
}
out.shrinkCapacity(toIndex);
}
void computePreciseJumpTargets(CodeBlock* codeBlock, Vector<InstructionStream::Offset, 32>& out)
{
computePreciseJumpTargetsInternal<ComputePreciseJumpTargetsMode::FollowCodeBlockClaim>(codeBlock, codeBlock->instructions(), out);
}
void computePreciseJumpTargets(CodeBlock* codeBlock, const InstructionStream& instructions, Vector<InstructionStream::Offset, 32>& out)
{
computePreciseJumpTargetsInternal<ComputePreciseJumpTargetsMode::FollowCodeBlockClaim>(codeBlock, instructions, out);
}
void computePreciseJumpTargets(UnlinkedCodeBlockGenerator* codeBlock, const InstructionStream& instructions, Vector<InstructionStream::Offset, 32>& out)
{
computePreciseJumpTargetsInternal<ComputePreciseJumpTargetsMode::FollowCodeBlockClaim>(codeBlock, instructions, out);
}
void recomputePreciseJumpTargets(UnlinkedCodeBlockGenerator* codeBlock, const InstructionStream& instructions, Vector<InstructionStream::Offset>& out)
{
computePreciseJumpTargetsInternal<ComputePreciseJumpTargetsMode::ForceCompute>(codeBlock, instructions, out);
}
void findJumpTargetsForInstruction(CodeBlock* codeBlock, const InstructionStream::Ref& instruction, Vector<InstructionStream::Offset, 1>& out)
{
getJumpTargetsForInstruction(codeBlock, instruction, out);
}
void findJumpTargetsForInstruction(UnlinkedCodeBlockGenerator* codeBlock, const InstructionStream::Ref& instruction, Vector<InstructionStream::Offset, 1>& out)
{
getJumpTargetsForInstruction(codeBlock, instruction, out);
}
} // namespace JSC