/** Find non-locals variables. Algorithm from Briggs, Cooper, Harvey and Simpson */
public BitSet findNonLocals() {
BitSet nonLocals = new BitSet(nbVar);
BitSet killed = new BitSet(nbVar);
BitSet emptySet = new BitSet(nbVar);
for (BasicBlock bb = firstBB; bb != null; bb = bb.getNext()) {
// clear killed set
killed.and(emptySet);
Iterator insts = bb.getInstructions();
while (insts.hasNext()) {
QInst inst = (QInst) insts.next();
QOperandBox[] ops = inst.getUses();
for (int i = 0; i < ops.length; ++i) {
QOperand op = ops[i].getOperand();
if (op instanceof QVar) {
int r = ((QVar) op).getRegister();
if (!killed.get(r)) {
nonLocals.set(r);
}
}
}
if (inst.defVar()) {
QOperand op = inst.getDefined().getOperand();
if (op instanceof QVar) {
int r = ((QVar) op).getRegister();
killed.set(r);
}
}
}
}
return nonLocals;
}
private void transformBasicBlock(BasicBlock block) {
List<Instruction> instructions = block.getInstructions();
for (int i = 0; i < instructions.size(); ++i) {
Instruction insn = instructions.get(i);
if (insn instanceof InvokeInstruction) {
InvokeInstruction invoke = (InvokeInstruction) insn;
List<Instruction> replacement = transformInvoke(invoke);
if (replacement != null) {
instructions.set(i, new EmptyInstruction());
instructions.addAll(i, replacement);
i += replacement.size();
}
}
}
}