Examples with BriefUnitGraph soot.toolkits.graph.BriefUnitGraph used on opensource projects

Example 6 with BriefUnitGraph

use of soot.toolkits.graph.BriefUnitGraph in project soot by Sable.

the class TryCatchCombiner method internalTransform.

protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
    int weight = soot.jbco.Main.getWeight(phaseName, b.getMethod().getSignature());
    if (weight == 0)
        return;
    int trapCount = 0;
    PatchingChain<Unit> units = b.getUnits();
    ArrayList<Unit> headList = new ArrayList<Unit>();
    ArrayList<Trap> trapList = new ArrayList<Trap>();
    Iterator<Trap> traps = b.getTraps().iterator();
    // build list of heads and corresponding traps
    while (traps.hasNext()) {
        Trap t = traps.next();
        totalcount++;
        // skip runtime exceptions
        if (!isRewritable(t))
            continue;
        headList.add(t.getBeginUnit());
        trapList.add(t);
        trapCount++;
    }
    if (trapCount == 0)
        return;
    // check if any traps have same head, if so insert dumby NOP to disambiguate
    for (int i = 0; i < headList.size(); i++) {
        for (int j = 0; j < headList.size(); j++) {
            if (i == j)
                continue;
            if (headList.get(i) == headList.get(j)) {
                Trap t = trapList.get(i);
                Unit nop = Baf.v().newNopInst();
                units.insertBeforeNoRedirect(nop, headList.get(i));
                headList.set(i, nop);
                t.setBeginUnit(nop);
            }
        }
    }
    Unit first = null;
    Iterator<Unit> uit = units.iterator();
    while (uit.hasNext()) {
        Unit unit = (Unit) uit.next();
        if (!(unit instanceof IdentityInst))
            break;
        first = unit;
    }
    if (first == null) {
        first = Baf.v().newNopInst();
        units.insertBefore(first, units.getFirst());
    } else {
        first = (Unit) units.getSuccOf(first);
    }
    Collection<Local> locs = b.getLocals();
    Map<Unit, Stack<Type>> stackHeightsBefore = null;
    Map<Local, Local> bafToJLocals = soot.jbco.Main.methods2Baf2JLocals.get(b.getMethod());
    int varCount = trapCount + 1;
    traps = b.getTraps().snapshotIterator();
    while (traps.hasNext()) {
        Trap t = traps.next();
        Unit begUnit = t.getBeginUnit();
        if (!isRewritable(t) || Rand.getInt(10) > weight)
            continue;
        stackHeightsBefore = StackTypeHeightCalculator.calculateStackHeights(b, bafToJLocals);
        boolean badType = false;
        @SuppressWarnings("unchecked") Stack<Type> s = (Stack<Type>) stackHeightsBefore.get(begUnit).clone();
        if (s.size() > 0) {
            for (int i = 0; i < s.size(); i++) {
                if (s.pop() instanceof StmtAddressType) {
                    badType = true;
                    break;
                }
            }
        }
        if (badType)
            continue;
        // local to hold control flow flag (0=try, 1=catch)
        Local controlLocal = Baf.v().newLocal("controlLocal_tccomb" + trapCount, IntType.v());
        locs.add(controlLocal);
        // initialize local to 0=try
        Unit pushZero = Baf.v().newPushInst(IntConstant.v(0));
        Unit storZero = Baf.v().newStoreInst(IntType.v(), controlLocal);
        // this is necessary even though it seems like it shouldn't be
        units.insertBeforeNoRedirect((Unit) pushZero.clone(), first);
        units.insertBeforeNoRedirect((Unit) storZero.clone(), first);
        BriefUnitGraph graph = new BriefUnitGraph(b);
        List<Unit> l = graph.getPredsOf(begUnit);
        // add initializer seq for try - sets local to zero and loads null exc
        units.add(pushZero);
        units.add(storZero);
        Stack<Local> varsToLoad = new Stack<Local>();
        s = stackHeightsBefore.get(begUnit);
        if (s.size() > 0) {
            for (int i = 0; i < s.size(); i++) {
                Type type = s.pop();
                Local varLocal = Baf.v().newLocal("varLocal_tccomb" + varCount++, type);
                locs.add(varLocal);
                varsToLoad.push(varLocal);
                units.add(Baf.v().newStoreInst(type, varLocal));
                units.insertBeforeNoRedirect(FixUndefinedLocals.getPushInitializer(varLocal, type), first);
                units.insertBeforeNoRedirect(Baf.v().newStoreInst(type, varLocal), first);
            }
        }
        units.add(Baf.v().newPushInst(NullConstant.v()));
        units.add(Baf.v().newGotoInst(begUnit));
        // for each pred of the beginUnit of the try, we must insert goto initializer
        for (int i = 0; i < l.size(); i++) {
            Unit pred = l.get(i);
            if (isIf(pred)) {
                TargetArgInst ifPred = ((TargetArgInst) pred);
                if (ifPred.getTarget() == begUnit) {
                    ifPred.setTarget(pushZero);
                }
                Unit succ = units.getSuccOf(ifPred);
                if (succ == begUnit) {
                    units.insertAfter(Baf.v().newGotoInst(pushZero), ifPred);
                }
            } else if (pred instanceof GotoInst && ((GotoInst) pred).getTarget() == begUnit) {
                ((GotoInst) pred).setTarget(pushZero);
            } else {
                units.insertAfter(Baf.v().newGotoInst(pushZero), pred);
            }
        }
        Unit handlerUnit = t.getHandlerUnit();
        Unit newBeginUnit = Baf.v().newLoadInst(IntType.v(), controlLocal);
        units.insertBefore(newBeginUnit, begUnit);
        units.insertBefore(Baf.v().newIfNeInst(handlerUnit), begUnit);
        units.insertBefore(Baf.v().newPopInst(RefType.v()), begUnit);
        while (varsToLoad.size() > 0) {
            Local varLocal = (Local) varsToLoad.pop();
            units.insertBefore(Baf.v().newLoadInst(varLocal.getType(), varLocal), begUnit);
        }
        try {
            SootField[] f = FieldRenamer.getRandomOpaques();
            if (f[0] != null && f[1] != null) {
                loadBooleanValue(units, f[0], begUnit);
                loadBooleanValue(units, f[1], begUnit);
                units.insertBeforeNoRedirect(Baf.v().newIfCmpEqInst(BooleanType.v(), begUnit), begUnit);
            }
        } catch (NullPointerException npe) {
        }
        // randomize the increment - sometimes store one, sometimes just set to 1
        if (Rand.getInt() % 2 == 0) {
            units.insertBeforeNoRedirect(Baf.v().newPushInst(IntConstant.v(Rand.getInt(3) + 1)), begUnit);
            units.insertBeforeNoRedirect(Baf.v().newStoreInst(IntType.v(), controlLocal), begUnit);
        } else {
            units.insertBeforeNoRedirect(Baf.v().newIncInst(controlLocal, IntConstant.v(Rand.getInt(3) + 1)), begUnit);
        }
        trapCount--;
        t.setBeginUnit(newBeginUnit);
        t.setHandlerUnit(newBeginUnit);
        changedcount++;
        if (debug)
            StackTypeHeightCalculator.printStack(units, StackTypeHeightCalculator.calculateStackHeights(b), false);
    }
}