private Set<SSA> directBlockLive(Set<SSA> liveJoin, BasicBlock joinBlock, BasicBlock headBlock) {
Set<SSA> liveDirectLast = new HashSet<SSA>();
liveDirectLast.addAll(liveJoin);
liveDirectLast.addAll(joinBlock.getPhiManager().getPhiDirects());
return buildIGRecursive(headBlock.getDirectSuccessor(), liveDirectLast);
}
public Set<SSA> buildIGRecursive(BasicBlock curBB, Set<SSA> liveLast) {
if (curBB.getJoinSuccessor() != null && curBB.getDirectSuccessor() != null) {
// liveness before the join block
BasicBlock joinBlock = curBB.getJoinSuccessor();
Set<SSA> liveJoin = buildIGRecursive(curBB.getJoinSuccessor(), liveLast);
this.connectPhiFuncs(liveJoin, joinBlock);
// liveness before the else block
Set<SSA> liveElseInitial = this.elseBlockLive(liveJoin, joinBlock, curBB);
// liveness before the if block
Set<SSA> liveDirectInitial = this.directBlockLive(liveJoin, joinBlock, curBB);
// merge liveDirect and liveELse
liveDirectInitial.addAll(liveElseInitial);
// build IG from initial block
Set<SSA> liveInitial = buildIGFromBlock(curBB, liveDirectInitial);
return liveInitial;
} else if (curBB.getDirectSuccessor() != null && curBB.getDirectSuccessor().isLoop()) {
BasicBlock loopHead = curBB.getDirectSuccessor();
// liveness before the follow block
BasicBlock followBlock = loopHead.getElseSuccessor();
Set<SSA> liveFollow = buildIGRecursive(followBlock, liveLast);
// liveness before the loop head
Set<SSA> liveLoopHead = buildIGFromBlock(loopHead, new HashSet<SSA>(liveFollow));
this.connectPhiFuncs(liveLoopHead, loopHead);
// liveness at the end of loop body
Set<SSA> liveLoopBodyInitial = this.loopBodyLive(liveLoopHead, loopHead);
// merge liveDirect and liveELse
liveLoopBodyInitial.addAll(liveFollow);
// liveness before the loop head again
Set<SSA> liveLoopHeadNew = buildIGFromBlock(loopHead, liveLoopBodyInitial);
this.connectPhiFuncs(liveLoopHeadNew, loopHead);
// the block before the loop head
Set<SSA> liveBeforeLoop = liveLoopHeadNew;
liveBeforeLoop.addAll(loopHead.getPhiManager().getPhiElses());
Set<SSA> liveInitial = buildIGFromBlock(curBB, liveBeforeLoop);
return liveInitial;
} else {
// if recursion reaches a normal block
Set<SSA> liveInitial = buildIGFromBlock(curBB, liveLast);
return liveInitial;
}
}
private Set<SSA> elseBlockLive(Set<SSA> liveJoin, BasicBlock joinBlock, BasicBlock headBlock) {
if (headBlock.getElseSuccessor() != headBlock.getJoinSuccessor()) {
Set<SSA> liveElseLast = new HashSet<SSA>();
liveElseLast.addAll(liveJoin);
liveElseLast.addAll(joinBlock.getPhiManager().getPhiElses());
return buildIGRecursive(headBlock.getElseSuccessor(), liveElseLast);
}
return new HashSet<SSA>();
}
private void connectPhiFuncs(Set<SSA> liveJoin, BasicBlock joinBlock) {
for (SSA result : joinBlock.getPhiManager().getPhiResults()) {
liveJoin.remove(result);
Cluster resultCluster = this.getCluster(result);
for (SSA x : liveJoin) {
Cluster xCluster = this.getCluster(x);
// add edge i <-> x
xCluster.connectWith(resultCluster);
}
}
}
private Set<SSA> buildIGFromBlock(BasicBlock curBB, Set<SSA> live) {
List<Instruction> instList = curBB.getInstructions();
for (int i = instList.size() - 1; i >= 0; i--) {
Instruction inst = instList.get(i);
// ignore phi function
if (inst.getOperator() == Instruction.phi) {
return live;
}
if (inst.getOperator() == Instruction.subroutine) {
live = this.buildIGRecursive(inst.getOperand2().block, live);
continue;
}
List<SSA> results = VariableManager.getSSAsByVersion(inst.getId());
// live = live - {i}
live.removeAll(results);
live.remove(null);
// for all x belong to live do
for (SSA result : results) {
Cluster resultCluster = this.getCluster(result);
for (SSA x : live) {
Cluster xCluster = this.getCluster(x);
// add edge i <-> x
xCluster.connectWith(resultCluster);
}
}
// live = live + {j, k}
if (inst.getOperand1() != null) {
SSA j = inst.getOperand1().ssa;
if (j != null) {
live.add(j);
}
}
if (inst.getOperand2() != null) {
SSA k = inst.getOperand2().ssa;
if (k != null) {
live.add(k);
}
}
}
return live;
}
private void insertSpillCode(Cluster x) {
for (int i = 0; i < x.getSSAList().size(); i++) {
Instruction assignInst = ControlFlowGraph.getInstruction(x.getSSAList().get(i).getVersion());
BasicBlock blockOfAssign = ControlFlowGraph.findBlockOf(assignInst);
Operand storeAddr = Operand.makeConst(spillMemory);
if (assignInst.getOperand1().kind == Operand.constant) {
Operand temp = Operand.makeReg(25);
Instruction store = Instruction.noUseInstruction(Instruction.store, temp, storeAddr);
store.setId(assignInst.getId());
blockOfAssign.replaceInst(assignInst, store);
Instruction move =
Instruction.noUseInstruction(Instruction.move, assignInst.getOperand1(), temp);
move.setId(store.getId() - 1);
blockOfAssign.insertBefore(store, move);
} else {
Instruction store =
Instruction.noUseInstruction(Instruction.store, assignInst.getOperand1(), storeAddr);
store.setId(assignInst.getId());
blockOfAssign.replaceInst(assignInst, store);
}
for (Operand use : x.getSSAList().get(i).getUseChain()) {
Instruction useInst = ControlFlowGraph.getInstruction(use.inst);
if (useInst != null && use.inst != x.getSSAList().get(i).getVersion()) {
BasicBlock blockOfUse = ControlFlowGraph.findBlockOf(useInst);
Operand loadAddr = Operand.makeConst(spillMemory);
Operand loadTemp = Operand.makeReg(26);
Instruction load = Instruction.noUseInstruction(Instruction.load, loadAddr, loadTemp);
blockOfUse.insertBefore(useInst, load);
if (useInst.getOperand1() != null && useInst.getOperand1().ssa == x.getSSAList().get(i)) {
useInst.setOperand1(loadTemp);
}
if (useInst.getOperand2() != null && useInst.getOperand2().ssa == x.getSSAList().get(i)) {
useInst.setOperand2(loadTemp);
}
}
}
}
}
private Set<SSA> loopBodyLive(Set<SSA> liveLoopBodyLast, BasicBlock loopHead) {
liveLoopBodyLast.addAll(loopHead.getPhiManager().getPhiDirects());
return buildIGRecursive(loopHead.getDirectSuccessor(), liveLoopBodyLast);
}