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>();
}