private BlockNode processIf(
IRegion currentRegion, BlockNode block, IfNode ifnode, RegionStack stack) {
if (block.contains(AFlag.SKIP)) {
// block already included in other 'if' region
return ifnode.getThenBlock();
}
IfInfo currentIf = makeIfInfo(block);
IfInfo mergedIf = mergeNestedIfNodes(currentIf);
if (mergedIf != null) {
currentIf = mergedIf;
} else {
// invert simple condition (compiler often do it)
currentIf = IfInfo.invert(currentIf);
}
IfInfo modifiedIf = IfMakerHelper.restructureIf(mth, block, currentIf);
if (modifiedIf != null) {
currentIf = modifiedIf;
} else {
if (currentIf.getMergedBlocks().size() <= 1) {
return null;
}
currentIf = makeIfInfo(block);
currentIf = IfMakerHelper.restructureIf(mth, block, currentIf);
if (currentIf == null) {
// all attempts failed
return null;
}
}
confirmMerge(currentIf);
IfRegion ifRegion = new IfRegion(currentRegion, block);
ifRegion.setCondition(currentIf.getCondition());
currentRegion.getSubBlocks().add(ifRegion);
stack.push(ifRegion);
stack.addExit(currentIf.getOutBlock());
ifRegion.setThenRegion(makeRegion(currentIf.getThenBlock(), stack));
BlockNode elseBlock = currentIf.getElseBlock();
if (elseBlock == null || stack.containsExit(elseBlock)) {
ifRegion.setElseRegion(null);
} else {
ifRegion.setElseRegion(makeRegion(elseBlock, stack));
}
stack.pop();
return currentIf.getOutBlock();
}
private BlockNode processLoop(IRegion curRegion, LoopInfo loop, RegionStack stack) {
BlockNode loopStart = loop.getStart();
Set<BlockNode> exitBlocksSet = loop.getExitNodes();
// set exit blocks scan order priority
// this can help if loop have several exits (after using 'break' or 'return' in loop)
List<BlockNode> exitBlocks = new ArrayList<BlockNode>(exitBlocksSet.size());
BlockNode nextStart = getNextBlock(loopStart);
if (nextStart != null && exitBlocksSet.remove(nextStart)) {
exitBlocks.add(nextStart);
}
if (exitBlocksSet.remove(loopStart)) {
exitBlocks.add(loopStart);
}
if (exitBlocksSet.remove(loop.getEnd())) {
exitBlocks.add(loop.getEnd());
}
exitBlocks.addAll(exitBlocksSet);
LoopRegion loopRegion = makeLoopRegion(curRegion, loop, exitBlocks);
if (loopRegion == null) {
BlockNode exit = makeEndlessLoop(curRegion, stack, loop, loopStart);
insertContinue(loop);
return exit;
}
curRegion.getSubBlocks().add(loopRegion);
IRegion outerRegion = stack.peekRegion();
stack.push(loopRegion);
IfInfo condInfo = makeIfInfo(loopRegion.getHeader());
condInfo = searchNestedIf(condInfo);
confirmMerge(condInfo);
if (!loop.getLoopBlocks().contains(condInfo.getThenBlock())) {
// invert loop condition if 'then' points to exit
condInfo = IfInfo.invert(condInfo);
}
loopRegion.setCondition(condInfo.getCondition());
exitBlocks.removeAll(condInfo.getMergedBlocks());
if (!exitBlocks.isEmpty()) {
BlockNode loopExit = condInfo.getElseBlock();
if (loopExit != null) {
// add 'break' instruction before path cross between main loop exit and sub-exit
for (Edge exitEdge : loop.getExitEdges()) {
if (!exitBlocks.contains(exitEdge.getSource())) {
continue;
}
insertBreak(stack, loopExit, exitEdge);
}
}
}
BlockNode out;
if (loopRegion.isConditionAtEnd()) {
BlockNode thenBlock = condInfo.getThenBlock();
out = thenBlock == loopStart ? condInfo.getElseBlock() : thenBlock;
loopStart.remove(AType.LOOP);
loop.getEnd().add(AFlag.SKIP);
stack.addExit(loop.getEnd());
loopRegion.setBody(makeRegion(loopStart, stack));
loopStart.addAttr(AType.LOOP, loop);
loop.getEnd().remove(AFlag.SKIP);
} else {
out = condInfo.getElseBlock();
if (outerRegion != null
&& out.contains(AFlag.LOOP_START)
&& !out.getAll(AType.LOOP).contains(loop)
&& RegionUtils.isRegionContainsBlock(outerRegion, out)) {
// exit to already processed outer loop
out = null;
}
stack.addExit(out);
BlockNode loopBody = condInfo.getThenBlock();
Region body = makeRegion(loopBody, stack);
// add blocks from loop start to first condition block
BlockNode conditionBlock = condInfo.getIfBlock();
if (loopStart != conditionBlock) {
Set<BlockNode> blocks = BlockUtils.getAllPathsBlocks(loopStart, conditionBlock);
blocks.remove(conditionBlock);
for (BlockNode block : blocks) {
if (block.getInstructions().isEmpty()
&& !block.contains(AFlag.SKIP)
&& !RegionUtils.isRegionContainsBlock(body, block)) {
body.add(block);
}
}
}
loopRegion.setBody(body);
}
stack.pop();
insertContinue(loop);
return out;
}
