Examples with LiveVarAnalysis jadx.core.dex.visitors.ssa.LiveVarAnalysis used on opensource projects

Example 1 with LiveVarAnalysis

use of jadx.core.dex.visitors.ssa.LiveVarAnalysis in project jadx by skylot.

the class BlockFinallyExtract method extractFinally.

/**
	 * Search and remove common code from 'catch' and 'handlers'.
	 */
private static boolean extractFinally(MethodNode mth, ExceptionHandler handler) {
    int count = handler.getBlocks().size();
    BitSet bs = new BitSet(count);
    List<BlockNode> blocks = new ArrayList<BlockNode>(count);
    for (BlockNode block : handler.getBlocks()) {
        List<InsnNode> insns = block.getInstructions();
        if (!insns.isEmpty()) {
            if (insns.get(0).getType() != InsnType.MOVE_EXCEPTION) {
                blocks.add(block);
            }
            bs.set(block.getId());
        }
    }
    if (blocks.isEmpty()) {
        // nothing to do
        return false;
    }
    List<BlocksRemoveInfo> removes = new LinkedList<BlocksRemoveInfo>();
    Set<BlockNode> splitters = new HashSet<BlockNode>();
    // remove 'finally' from handlers
    TryCatchBlock tryBlock = handler.getTryBlock();
    if (tryBlock.getHandlersCount() > 1) {
        for (ExceptionHandler otherHandler : tryBlock.getHandlers()) {
            if (otherHandler == handler) {
                continue;
            }
            for (BlockNode hb : otherHandler.getBlocks()) {
                BlocksRemoveInfo removeInfo = removeInsns(mth, hb, blocks, bs);
                if (removeInfo != null) {
                    removes.add(removeInfo);
                    break;
                }
            }
        }
        if (removes.size() != tryBlock.getHandlersCount() - 1) {
            return false;
        }
    }
    for (ExceptionHandler otherHandler : tryBlock.getHandlers()) {
        SplitterBlockAttr splitterAttr = otherHandler.getHandlerBlock().get(AType.SPLITTER_BLOCK);
        if (splitterAttr != null) {
            BlockNode splBlock = splitterAttr.getBlock();
            if (!splBlock.getCleanSuccessors().isEmpty()) {
                splitters.add(splBlock);
            }
        }
    }
    // remove 'finally' from 'try' blocks (dominated by splitter block)
    boolean removed = false;
    for (BlockNode splitter : splitters) {
        BlockNode start = splitter.getCleanSuccessors().get(0);
        List<BlockNode> list = BlockUtils.collectBlocksDominatedBy(splitter, start);
        for (BlockNode block : list) {
            if (bs.get(block.getId())) {
                continue;
            }
            BlocksRemoveInfo removeInfo = removeInsns(mth, block, blocks, bs);
            if (removeInfo != null) {
                removes.add(removeInfo);
                removed = true;
                break;
            }
        }
    }
    if (!removed) {
        return false;
    }
    // 'finally' extract confirmed, run remove steps
    LiveVarAnalysis laBefore = null;
    boolean runReMap = isReMapNeeded(removes);
    if (runReMap) {
        laBefore = new LiveVarAnalysis(mth);
        laBefore.runAnalysis();
    }
    for (BlocksRemoveInfo removeInfo : removes) {
        if (!applyRemove(mth, removeInfo)) {
            return false;
        }
    }
    LiveVarAnalysis laAfter = null;
    // remove 'move-exception' instruction
    BlockNode handlerBlock = handler.getHandlerBlock();
    InsnNode me = BlockUtils.getLastInsn(handlerBlock);
    if (me != null && me.getType() == InsnType.MOVE_EXCEPTION) {
        boolean replaced = false;
        List<InsnNode> insnsList = handlerBlock.getInstructions();
        if (!handlerBlock.getCleanSuccessors().isEmpty()) {
            laAfter = new LiveVarAnalysis(mth);
            laAfter.runAnalysis();
            RegisterArg resArg = me.getResult();
            BlockNode succ = handlerBlock.getCleanSuccessors().get(0);
            if (laAfter.isLive(succ, resArg.getRegNum())) {
                // kill variable
                InsnNode kill = new InsnNode(InsnType.NOP, 0);
                kill.setResult(resArg);
                kill.add(AFlag.REMOVE);
                insnsList.set(insnsList.size() - 1, kill);
                replaced = true;
            }
        }
        if (!replaced) {
            insnsList.remove(insnsList.size() - 1);
            handlerBlock.add(AFlag.SKIP);
        }
    }
    // generate 'move' instruction for mapped register pairs
    if (runReMap) {
        if (laAfter == null) {
            laAfter = new LiveVarAnalysis(mth);
            laAfter.runAnalysis();
        }
        performVariablesReMap(mth, removes, laBefore, laAfter);
    }
    handler.setFinally(true);
    return true;
}