PreciseJumpTargets.cpp [plain text]
#include "config.h"
#include "PreciseJumpTargets.h"
namespace JSC {
static void addSimpleSwitchTargets(SimpleJumpTable& jumpTable, unsigned bytecodeOffset, Vector<unsigned, 32>& out)
{
for (unsigned i = jumpTable.branchOffsets.size(); i--;)
out.append(bytecodeOffset + jumpTable.branchOffsets[i]);
}
void computePreciseJumpTargets(CodeBlock* codeBlock, Vector<unsigned, 32>& out)
{
ASSERT(out.isEmpty());
if (!codeBlock->numberOfJumpTargets())
return;
for (unsigned i = codeBlock->numberOfExceptionHandlers(); i--;)
out.append(codeBlock->exceptionHandler(i).target);
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);
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:
out.append(bytecodeOffset + current[3].u.operand);
break;
case op_switch_imm:
addSimpleSwitchTargets(codeBlock->immediateSwitchJumpTable(current[1].u.operand), bytecodeOffset, out);
out.append(bytecodeOffset + current[2].u.operand);
break;
case op_switch_char:
addSimpleSwitchTargets(codeBlock->characterSwitchJumpTable(current[1].u.operand), bytecodeOffset, out);
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_get_pnames:
out.append(bytecodeOffset + current[5].u.operand);
break;
case op_next_pname:
out.append(bytecodeOffset + current[6].u.operand);
break;
case op_check_has_instance:
out.append(bytecodeOffset + current[4].u.operand);
break;
case op_loop_hint:
out.append(bytecodeOffset);
break;
default:
break;
}
bytecodeOffset += opcodeLengths[opcodeID];
}
std::sort(out.begin(), out.end());
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);
}
}