Examples with IntList com.android.dx.util.IntList used on opensource projects

Example 26 with IntList

use of com.android.dx.util.IntList in project J2ME-Loader by nikita36078.

the class RopTranslator method pickOrder.

/**
 * Picks an order for the blocks by doing "trace" analysis.
 */
private void pickOrder() {
    BasicBlockList blocks = method.getBlocks();
    int sz = blocks.size();
    int maxLabel = blocks.getMaxLabel();
    int[] workSet = Bits.makeBitSet(maxLabel);
    int[] tracebackSet = Bits.makeBitSet(maxLabel);
    for (int i = 0; i < sz; i++) {
        BasicBlock one = blocks.get(i);
        Bits.set(workSet, one.getLabel());
    }
    int[] order = new int[sz];
    int at = 0;
    /*
         * Starting with the designated "first label" (that is, the
         * first block of the method), add that label to the order,
         * and then pick its first as-yet unordered successor to
         * immediately follow it, giving top priority to the primary
         * (aka default) successor (if any). Keep following successors
         * until the trace runs out of possibilities. Then, continue
         * by finding an unordered chain containing the first as-yet
         * unordered block, and adding it to the order, and so on.
         */
    for (int label = method.getFirstLabel(); label != -1; label = Bits.findFirst(workSet, 0)) {
        /*
             * Attempt to trace backward from the chosen block to an
             * as-yet unordered predecessor which lists the chosen
             * block as its primary successor, and so on, until we
             * fail to find such an unordered predecessor. Start the
             * trace with that block. Note that the first block in the
             * method has no predecessors, so in that case this loop
             * will simply terminate with zero iterations and without
             * picking a new starter block.
             */
        traceBack: for (; ; ) {
            IntList preds = method.labelToPredecessors(label);
            int psz = preds.size();
            for (int i = 0; i < psz; i++) {
                int predLabel = preds.get(i);
                if (Bits.get(tracebackSet, predLabel)) {
                    /*
                         * We found a predecessor loop; stop tracing back
                         * from here.
                         */
                    break;
                }
                if (!Bits.get(workSet, predLabel)) {
                    // This one's already ordered.
                    continue;
                }
                BasicBlock pred = blocks.labelToBlock(predLabel);
                if (pred.getPrimarySuccessor() == label) {
                    // Found one!
                    label = predLabel;
                    Bits.set(tracebackSet, label);
                    continue traceBack;
                }
            }
            // Failed to find a better block to start the trace.
            break;
        }
        /*
             * Trace a path from the chosen block to one of its
             * unordered successors (hopefully the primary), and so
             * on, until we run out of unordered successors.
             */
        while (label != -1) {
            Bits.clear(workSet, label);
            Bits.clear(tracebackSet, label);
            order[at] = label;
            at++;
            BasicBlock one = blocks.labelToBlock(label);
            BasicBlock preferredBlock = blocks.preferredSuccessorOf(one);
            if (preferredBlock == null) {
                break;
            }
            int preferred = preferredBlock.getLabel();
            int primary = one.getPrimarySuccessor();
            if (Bits.get(workSet, preferred)) {
                /*
                     * Order the current block's preferred successor
                     * next, as it has yet to be scheduled.
                     */
                label = preferred;
            } else if ((primary != preferred) && (primary >= 0) && Bits.get(workSet, primary)) {
                /*
                     * The primary is available, so use that.
                     */
                label = primary;
            } else {
                /*
                     * There's no obvious candidate, so pick the first
                     * one that's available, if any.
                     */
                IntList successors = one.getSuccessors();
                int ssz = successors.size();
                label = -1;
                for (int i = 0; i < ssz; i++) {
                    int candidate = successors.get(i);
                    if (Bits.get(workSet, candidate)) {
                        label = candidate;
                        break;
                    }
                }
            }
        }
    }
    if (at != sz) {
        // There was a duplicate block label.
        throw new RuntimeException("shouldn't happen");
    }
    this.order = order;
}

Example 27 with IntList

use of com.android.dx.util.IntList in project J2ME-Loader by nikita36078.

the class StdCatchBuilder method handlersFor.

/**
 * Makes the {@link CatchHandlerList} for the given basic block.
 *
 * @param block {@code non-null;} block to get entries for
 * @param addresses {@code non-null;} address objects for each block
 * @return {@code non-null;} array of entries
 */
private static CatchHandlerList handlersFor(BasicBlock block, BlockAddresses addresses) {
    IntList successors = block.getSuccessors();
    int succSize = successors.size();
    int primary = block.getPrimarySuccessor();
    TypeList catches = block.getLastInsn().getCatches();
    int catchSize = catches.size();
    if (catchSize == 0) {
        return CatchHandlerList.EMPTY;
    }
    if (((primary == -1) && (succSize != catchSize)) || ((primary != -1) && ((succSize != (catchSize + 1)) || (primary != successors.get(catchSize))))) {
        /*
             * Blocks that throw are supposed to list their primary
             * successor -- if any -- last in the successors list, but
             * that constraint appears to be violated here.
             */
        throw new RuntimeException("shouldn't happen: weird successors list");
    }
    /*
         * Reduce the effective catchSize if we spot a catch-all that
         * isn't at the end.
         */
    for (int i = 0; i < catchSize; i++) {
        Type type = catches.getType(i);
        if (type.equals(Type.OBJECT)) {
            catchSize = i + 1;
            break;
        }
    }
    CatchHandlerList result = new CatchHandlerList(catchSize);
    for (int i = 0; i < catchSize; i++) {
        CstType oneType = new CstType(catches.getType(i));
        CodeAddress oneHandler = addresses.getStart(successors.get(i));
        result.set(i, oneType, oneHandler.getAddress());
    }
    result.setImmutable();
    return result;
}

Example 28 with IntList

use of com.android.dx.util.IntList in project J2ME-Loader by nikita36078.

the class BasicBlockList method preferredSuccessorOf.

/**
 * Gets the preferred successor for the given block. If the block
 * only has one successor, then that is the preferred successor.
 * Otherwise, if the block has a primay successor, then that is
 * the preferred successor. If the block has no successors, then
 * this returns {@code null}.
 *
 * @param block {@code non-null;} the block in question
 * @return {@code null-ok;} the preferred successor, if any
 */
public BasicBlock preferredSuccessorOf(BasicBlock block) {
    int primarySuccessor = block.getPrimarySuccessor();
    IntList successors = block.getSuccessors();
    int succSize = successors.size();
    switch(succSize) {
        case 0:
            {
                return null;
            }
        case 1:
            {
                return labelToBlock(successors.get(0));
            }
    }
    if (primarySuccessor != -1) {
        return labelToBlock(primarySuccessor);
    } else {
        return labelToBlock(successors.get(0));
    }
}

Example 29 with IntList

use of com.android.dx.util.IntList in project buck by facebook.

the class IdenticalBlockCombiner method process.

/**
     * Runs algorithm. TODO: This is n^2, and could be made linear-ish with
     * a hash. In particular, hash the contents of each block and only
     * compare blocks with the same hash.
     *
     * @return {@code non-null;} new method that has been processed
     */
public RopMethod process() {
    int szBlocks = blocks.size();
    // indexed by label
    BitSet toDelete = new BitSet(blocks.getMaxLabel());
    // For each non-deleted block...
    for (int bindex = 0; bindex < szBlocks; bindex++) {
        BasicBlock b = blocks.get(bindex);
        if (toDelete.get(b.getLabel())) {
            // doomed block
            continue;
        }
        IntList preds = ropMethod.labelToPredecessors(b.getLabel());
        // ...look at all of it's predecessors that have only one succ...
        int szPreds = preds.size();
        for (int i = 0; i < szPreds; i++) {
            int iLabel = preds.get(i);
            BasicBlock iBlock = blocks.labelToBlock(iLabel);
            if (toDelete.get(iLabel) || iBlock.getSuccessors().size() > 1 || iBlock.getFirstInsn().getOpcode().getOpcode() == RegOps.MOVE_RESULT) {
                continue;
            }
            IntList toCombine = new IntList();
            // ...and see if they can be combined with any other preds...
            for (int j = i + 1; j < szPreds; j++) {
                int jLabel = preds.get(j);
                BasicBlock jBlock = blocks.labelToBlock(jLabel);
                if (jBlock.getSuccessors().size() == 1 && compareInsns(iBlock, jBlock)) {
                    toCombine.add(jLabel);
                    toDelete.set(jLabel);
                }
            }
            combineBlocks(iLabel, toCombine);
        }
    }
    for (int i = szBlocks - 1; i >= 0; i--) {
        if (toDelete.get(newBlocks.get(i).getLabel())) {
            newBlocks.set(i, null);
        }
    }
    newBlocks.shrinkToFit();
    newBlocks.setImmutable();
    return new RopMethod(newBlocks, ropMethod.getFirstLabel());
}

Example 30 with IntList

use of com.android.dx.util.IntList in project buck by facebook.

the class IdenticalBlockCombiner method replaceSucc.

/**
     * Replaces one of a block's successors with a different label. Constructs
     * an updated BasicBlock instance and places it in {@code newBlocks}.
     *
     * @param block block to replace
     * @param oldLabel label of successor to replace
     * @param newLabel label of new successor
     */
private void replaceSucc(BasicBlock block, int oldLabel, int newLabel) {
    IntList newSuccessors = block.getSuccessors().mutableCopy();
    int newPrimarySuccessor;
    newSuccessors.set(newSuccessors.indexOf(oldLabel), newLabel);
    newPrimarySuccessor = block.getPrimarySuccessor();
    if (newPrimarySuccessor == oldLabel) {
        newPrimarySuccessor = newLabel;
    }
    newSuccessors.setImmutable();
    BasicBlock newBB = new BasicBlock(block.getLabel(), block.getInsns(), newSuccessors, newPrimarySuccessor);
    newBlocks.set(newBlocks.indexOfLabel(block.getLabel()), newBB);
}