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/*
* Copyright (C) 2013 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 "JSCInlines.h"
namespace JSC {
template <size_t vectorSize>
static void getJumpTargetsForBytecodeOffset(CodeBlock* codeBlock, Interpreter* interpreter, Instruction* instructionsBegin, unsigned bytecodeOffset, Vector<unsigned, vectorSize>& out)
{
OpcodeID opcodeID = interpreter->getOpcodeID(instructionsBegin[bytecodeOffset].u.opcode);
Instruction* current = instructionsBegin + bytecodeOffset;
switch (opcodeID) {
case op_jmp:
out.append(bytecodeOffset + current[1].u.operand);
break;
case op_jtrue:
case op_jfalse:
case op_jeq_null:
case op_jneq_null:
out.append(bytecodeOffset + current[2].u.operand);
break;
case op_jneq_ptr:
case op_jless:
case op_jlesseq:
case op_jgreater:
case op_jgreatereq:
case op_jnless:
case op_jnlesseq:
case op_jngreater:
case op_jngreatereq:
case op_save: // The jump of op_save is purely for calculating liveness.
out.append(bytecodeOffset + current[3].u.operand);
break;
case op_switch_imm:
case op_switch_char: {
SimpleJumpTable& table = codeBlock->switchJumpTable(current[1].u.operand);
for (unsigned i = table.branchOffsets.size(); i--;)
out.append(bytecodeOffset + table.branchOffsets[i]);
out.append(bytecodeOffset + current[2].u.operand);
break;
}
case op_switch_string: {
StringJumpTable& table = codeBlock->stringSwitchJumpTable(current[1].u.operand);
StringJumpTable::StringOffsetTable::iterator iter = table.offsetTable.begin();
StringJumpTable::StringOffsetTable::iterator end = table.offsetTable.end();
for (; iter != end; ++iter)
out.append(bytecodeOffset + iter->value.branchOffset);
out.append(bytecodeOffset + current[2].u.operand);
break;
}
case op_loop_hint:
out.append(bytecodeOffset);
break;
default:
break;
}
}
void computePreciseJumpTargets(CodeBlock* codeBlock, Vector<unsigned, 32>& out)
{
ASSERT(out.isEmpty());
// We will derive a superset of the jump targets that the code block thinks it has.
// So, if the code block claims there are none, then we are done.
if (!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);
}
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
unsigned instructionCount = codeBlock->instructions().size();
for (unsigned bytecodeOffset = 0; bytecodeOffset < instructionCount;) {
OpcodeID opcodeID = interpreter->getOpcodeID(instructionsBegin[bytecodeOffset].u.opcode);
getJumpTargetsForBytecodeOffset(codeBlock, interpreter, instructionsBegin, bytecodeOffset, out);
bytecodeOffset += opcodeLengths[opcodeID];
}
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.resize(toIndex);
out.shrinkToFit();
}
void findJumpTargetsForBytecodeOffset(CodeBlock* codeBlock, unsigned bytecodeOffset, Vector<unsigned, 1>& out)
{
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
getJumpTargetsForBytecodeOffset(codeBlock, interpreter, instructionsBegin, bytecodeOffset, out);
}
} // namespace JSC
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