private static boolean canInsertContinue(
BlockNode pred,
List<BlockNode> predecessors,
BlockNode loopEnd,
Set<BlockNode> loopExitNodes) {
if (!pred.contains(AFlag.SYNTHETIC) || BlockUtils.checkLastInsnType(pred, InsnType.CONTINUE)) {
return false;
}
List<BlockNode> preds = pred.getPredecessors();
if (preds.isEmpty()) {
return false;
}
BlockNode codePred = preds.get(0);
if (codePred.contains(AFlag.SKIP)) {
return false;
}
if (loopEnd.isDominator(codePred) || loopExitNodes.contains(codePred)) {
return false;
}
if (isDominatedOnBlocks(codePred, predecessors)) {
return false;
}
boolean gotoExit = false;
for (BlockNode exit : loopExitNodes) {
if (BlockUtils.isPathExists(codePred, exit)) {
gotoExit = true;
break;
}
}
return gotoExit;
}
private static void renameVar(MethodNode mth, SSAVar[] vars, int[] vers, BlockNode block) {
SSAVar[] inputVars = Arrays.copyOf(vars, vars.length);
for (InsnNode insn : block.getInstructions()) {
if (insn.getType() != InsnType.PHI) {
for (InsnArg arg : insn.getArguments()) {
if (!arg.isRegister()) {
continue;
}
RegisterArg reg = (RegisterArg) arg;
int regNum = reg.getRegNum();
SSAVar var = vars[regNum];
if (var == null) {
throw new JadxRuntimeException(
"Not initialized variable reg: "
+ regNum
+ ", insn: "
+ insn
+ ", block:"
+ block
+ ", method: "
+ mth);
}
var.use(reg);
}
}
RegisterArg result = insn.getResult();
if (result != null) {
int regNum = result.getRegNum();
vars[regNum] = mth.makeNewSVar(regNum, vers, result);
}
}
for (BlockNode s : block.getSuccessors()) {
PhiListAttr phiList = s.get(AType.PHI_LIST);
if (phiList == null) {
continue;
}
int j = s.getPredecessors().indexOf(block);
if (j == -1) {
throw new JadxRuntimeException("Can't find predecessor for " + block + " " + s);
}
for (PhiInsn phiInsn : phiList.getList()) {
if (j >= phiInsn.getArgsCount()) {
continue;
}
int regNum = phiInsn.getResult().getRegNum();
SSAVar var = vars[regNum];
if (var == null) {
continue;
}
var.use(phiInsn.getArg(j));
var.setUsedInPhi(phiInsn);
}
}
for (BlockNode domOn : block.getDominatesOn()) {
renameVar(mth, vars, vers, domOn);
}
System.arraycopy(inputVars, 0, vars, 0, vars.length);
}
private static void addPhi(BlockNode block, int regNum) {
PhiListAttr phiList = block.get(AType.PHI_LIST);
if (phiList == null) {
phiList = new PhiListAttr();
block.addAttr(phiList);
}
PhiInsn phiInsn = new PhiInsn(regNum, block.getPredecessors().size());
phiList.getList().add(phiInsn);
phiInsn.setOffset(block.getStartOffset());
block.getInstructions().add(0, phiInsn);
}
/** Select loop exit and construct LoopRegion */
private LoopRegion makeLoopRegion(IRegion curRegion, LoopInfo loop, List<BlockNode> exitBlocks) {
for (BlockNode block : exitBlocks) {
if (block.contains(AType.EXC_HANDLER)
|| block.getInstructions().size() != 1
|| block.getInstructions().get(0).getType() != InsnType.IF) {
continue;
}
List<LoopInfo> loops = block.getAll(AType.LOOP);
if (!loops.isEmpty() && loops.get(0) != loop) {
// skip nested loop condition
continue;
}
LoopRegion loopRegion = new LoopRegion(curRegion, loop, block, block == loop.getEnd());
boolean found;
if (block == loop.getStart()
|| block == loop.getEnd()
|| BlockUtils.isEmptySimplePath(loop.getStart(), block)) {
found = true;
} else if (block.getPredecessors().contains(loop.getStart())) {
loopRegion.setPreCondition(loop.getStart());
// if we can't merge pre-condition this is not correct header
found = loopRegion.checkPreCondition();
} else {
found = false;
}
if (found) {
List<LoopInfo> list = mth.getAllLoopsForBlock(block);
if (list.size() >= 2) {
// bad condition if successors going out of all loops
boolean allOuter = true;
for (BlockNode outerBlock : block.getCleanSuccessors()) {
List<LoopInfo> outLoopList = mth.getAllLoopsForBlock(outerBlock);
outLoopList.remove(loop);
if (!outLoopList.isEmpty()) {
// goes to outer loop
allOuter = false;
break;
}
}
if (allOuter) {
found = false;
}
}
}
if (found) {
return loopRegion;
}
}
// no exit found => endless loop
return null;
}
private static void insertContinue(LoopInfo loop) {
BlockNode loopEnd = loop.getEnd();
List<BlockNode> predecessors = loopEnd.getPredecessors();
if (predecessors.size() <= 1) {
return;
}
Set<BlockNode> loopExitNodes = loop.getExitNodes();
for (BlockNode pred : predecessors) {
if (canInsertContinue(pred, predecessors, loopEnd, loopExitNodes)) {
InsnNode cont = new InsnNode(InsnType.CONTINUE, 0);
pred.getInstructions().add(cont);
}
}
}
private static void insertContinueInSwitch(BlockNode block, BlockNode out, BlockNode end) {
int endId = end.getId();
for (BlockNode s : block.getCleanSuccessors()) {
if (s.getDomFrontier().get(endId) && s != out) {
// search predecessor of loop end on path from this successor
List<BlockNode> list = BlockUtils.collectBlocksDominatedBy(s, s);
for (BlockNode p : end.getPredecessors()) {
if (list.contains(p)) {
if (p.isSynthetic()) {
p.getInstructions().add(new InsnNode(InsnType.CONTINUE, 0));
}
break;
}
}
}
}
}
public void processTryCatchBlocks(MethodNode mth) {
Set<TryCatchBlock> tcs = new HashSet<TryCatchBlock>();
for (ExceptionHandler handler : mth.getExceptionHandlers()) {
tcs.add(handler.getTryBlock());
}
for (TryCatchBlock tc : tcs) {
List<BlockNode> blocks = new ArrayList<BlockNode>(tc.getHandlersCount());
Set<BlockNode> splitters = new HashSet<BlockNode>();
for (ExceptionHandler handler : tc.getHandlers()) {
BlockNode handlerBlock = handler.getHandlerBlock();
if (handlerBlock != null) {
blocks.add(handlerBlock);
splitters.addAll(handlerBlock.getPredecessors());
} else {
LOG.debug(ErrorsCounter.formatErrorMsg(mth, "No exception handler block: " + handler));
}
}
Set<BlockNode> exits = new HashSet<BlockNode>();
for (BlockNode splitter : splitters) {
for (BlockNode handler : blocks) {
List<BlockNode> s = splitter.getSuccessors();
if (s.isEmpty()) {
LOG.debug(ErrorsCounter.formatErrorMsg(mth, "No successors for splitter: " + splitter));
continue;
}
BlockNode ss = s.get(0);
BlockNode cross = BlockUtils.getPathCross(mth, ss, handler);
if (cross != null && cross != ss && cross != handler) {
exits.add(cross);
}
}
}
for (ExceptionHandler handler : tc.getHandlers()) {
processExcHandler(handler, exits);
}
}
}