Examples with UnknownType soot.UnknownType used on opensource projects

Example 1 with UnknownType

use of soot.UnknownType in project soot by Sable.

the class DeadAssignmentEliminator method internalTransform.

/**
 * Eliminates dead code in a linear fashion.  Complexity is linear
 * with respect to the statements.
 *
 * Does not work on grimp code because of the check on the right hand
 * side for side effects.
 */
@Override
protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
    boolean eliminateOnlyStackLocals = PhaseOptions.getBoolean(options, "only-stack-locals");
    final Options soptions = Options.v();
    if (soptions.verbose()) {
        logger.debug("[" + b.getMethod().getName() + "] Eliminating dead code...");
    }
    if (soptions.time()) {
        Timers.v().deadCodeTimer.start();
    }
    Chain<Unit> units = b.getUnits();
    Deque<Unit> q = new ArrayDeque<Unit>(units.size());
    // Make a first pass through the statements, noting
    // the statements we must absolutely keep.
    boolean isStatic = b.getMethod().isStatic();
    boolean allEssential = true;
    boolean checkInvoke = false;
    Local thisLocal = null;
    for (Iterator<Unit> it = units.iterator(); it.hasNext(); ) {
        Unit s = it.next();
        boolean isEssential = true;
        if (s instanceof NopStmt) {
            // Hack: do not remove nop if is is used for a Trap
            // which is at the very end of the code.
            boolean removeNop = it.hasNext();
            if (!removeNop) {
                removeNop = true;
                for (Trap t : b.getTraps()) {
                    if (t.getEndUnit() == s) {
                        removeNop = false;
                        break;
                    }
                }
            }
            if (removeNop) {
                it.remove();
                continue;
            }
        } else if (s instanceof AssignStmt) {
            AssignStmt as = (AssignStmt) s;
            Value lhs = as.getLeftOp();
            Value rhs = as.getRightOp();
            // Stmt is of the form a = a which is useless
            if (lhs == rhs && lhs instanceof Local) {
                it.remove();
                continue;
            }
            if (lhs instanceof Local && (!eliminateOnlyStackLocals || ((Local) lhs).getName().startsWith("$") || lhs.getType() instanceof NullType)) {
                isEssential = false;
                if (!checkInvoke) {
                    checkInvoke = as.containsInvokeExpr();
                }
                if (rhs instanceof CastExpr) {
                    // CastExpr          : can trigger ClassCastException, but null-casts never fail
                    CastExpr ce = (CastExpr) rhs;
                    Type t = ce.getCastType();
                    Value v = ce.getOp();
                    isEssential = !(v instanceof NullConstant && t instanceof RefType);
                } else if (rhs instanceof InvokeExpr || rhs instanceof ArrayRef || rhs instanceof NewExpr || rhs instanceof NewArrayExpr || rhs instanceof NewMultiArrayExpr) {
                    // ArrayRef          : can have side effects (like throwing a null pointer exception)
                    // InvokeExpr        : can have side effects (like throwing a null pointer exception)
                    // NewArrayExpr      : can throw exception
                    // NewMultiArrayExpr : can throw exception
                    // NewExpr           : can trigger class initialization
                    isEssential = true;
                } else if (rhs instanceof FieldRef) {
                    // Can trigger class initialization
                    isEssential = true;
                    if (rhs instanceof InstanceFieldRef) {
                        InstanceFieldRef ifr = (InstanceFieldRef) rhs;
                        if (!isStatic && thisLocal == null) {
                            thisLocal = b.getThisLocal();
                        }
                        // Any InstanceFieldRef may have side effects,
                        // unless the base is reading from 'this'
                        // in a non-static method
                        isEssential = (isStatic || thisLocal != ifr.getBase());
                    }
                } else if (rhs instanceof DivExpr || rhs instanceof RemExpr) {
                    BinopExpr expr = (BinopExpr) rhs;
                    Type t1 = expr.getOp1().getType();
                    Type t2 = expr.getOp2().getType();
                    // Can trigger a division by zero
                    boolean t2Int = t2 instanceof IntType;
                    isEssential = t2Int || t1 instanceof IntType || t1 instanceof LongType || t2 instanceof LongType || t1 instanceof UnknownType || t2 instanceof UnknownType;
                    if (isEssential && t2Int) {
                        Value v = expr.getOp2();
                        if (v instanceof IntConstant) {
                            IntConstant i = (IntConstant) v;
                            isEssential = (i.value == 0);
                        } else
                            // could be 0, we don't know
                            isEssential = true;
                    }
                    if (isEssential && t2 instanceof LongType) {
                        Value v = expr.getOp2();
                        if (v instanceof LongConstant) {
                            LongConstant l = (LongConstant) v;
                            isEssential = (l.value == 0);
                        } else
                            // could be 0, we don't know
                            isEssential = true;
                    }
                }
            }
        }
        if (isEssential) {
            q.addFirst(s);
        }
        allEssential &= isEssential;
    }
    if (checkInvoke || !allEssential) {
        // Add all the statements which are used to compute values
        // for the essential statements, recursively
        final LocalDefs localDefs = LocalDefs.Factory.newLocalDefs(b);
        if (!allEssential) {
            Set<Unit> essential = new HashSet<Unit>(b.getUnits().size());
            while (!q.isEmpty()) {
                Unit s = q.removeFirst();
                if (essential.add(s)) {
                    for (ValueBox box : s.getUseBoxes()) {
                        Value v = box.getValue();
                        if (v instanceof Local) {
                            Local l = (Local) v;
                            List<Unit> defs = localDefs.getDefsOfAt(l, s);
                            if (defs != null)
                                q.addAll(defs);
                        }
                    }
                }
            }
            // Remove the dead statements
            units.retainAll(essential);
        }
        if (checkInvoke) {
            final LocalUses localUses = LocalUses.Factory.newLocalUses(b, localDefs);
            // Eliminate dead assignments from invokes such as x = f(), where
            // x is no longer used
            List<AssignStmt> postProcess = new ArrayList<AssignStmt>();
            for (Unit u : units) {
                if (u instanceof AssignStmt) {
                    AssignStmt s = (AssignStmt) u;
                    if (s.containsInvokeExpr()) {
                        // Just find one use of l which is essential
                        boolean deadAssignment = true;
                        for (UnitValueBoxPair pair : localUses.getUsesOf(s)) {
                            if (units.contains(pair.unit)) {
                                deadAssignment = false;
                                break;
                            }
                        }
                        if (deadAssignment) {
                            postProcess.add(s);
                        }
                    }
                }
            }
            final Jimple jimple = Jimple.v();
            for (AssignStmt s : postProcess) {
                // Transform it into a simple invoke.
                Stmt newInvoke = jimple.newInvokeStmt(s.getInvokeExpr());
                newInvoke.addAllTagsOf(s);
                units.swapWith(s, newInvoke);
                // If we have a callgraph, we need to fix it
                if (Scene.v().hasCallGraph())
                    Scene.v().getCallGraph().swapEdgesOutOf(s, newInvoke);
            }
        }
    }
    if (soptions.time()) {
        Timers.v().deadCodeTimer.end();
    }
}

Example 2 with UnknownType

use of soot.UnknownType in project soot by Sable.

the class DalvikTyper method assignType.

@Override
public void assignType(final Body b) {
    // Debug.printDbg("assignTypes: before: \n", b);
    constraints.clear();
    localObjList.clear();
    final Set<Unit> todoUnits = new HashSet<Unit>();
    // put constraints:
    for (Unit u : b.getUnits()) {
        StmtSwitch ss = new StmtSwitch() {

            @Override
            public void caseBreakpointStmt(BreakpointStmt stmt) {
            // nothing
            }

            @Override
            public void caseInvokeStmt(InvokeStmt stmt) {
                // add constraint
                DalvikTyper.v().setInvokeType(stmt.getInvokeExpr());
            }

            @Override
            public void caseAssignStmt(AssignStmt stmt) {
                // add constraint
                Value l = stmt.getLeftOp();
                Value r = stmt.getRightOp();
                // size in new array expression is of tye integer
                if (r instanceof NewArrayExpr) {
                    NewArrayExpr nae = (NewArrayExpr) r;
                    ValueBox sb = nae.getSizeBox();
                    if (sb.getValue() instanceof Local) {
                        DalvikTyper.v().setType(sb, IntType.v(), true);
                    }
                }
                // array index is of type integer
                if (stmt.containsArrayRef()) {
                    ArrayRef ar = stmt.getArrayRef();
                    ValueBox sb = ar.getIndexBox();
                    if (sb.getValue() instanceof Local) {
                        DalvikTyper.v().setType(sb, IntType.v(), true);
                    }
                }
                if (l instanceof Local && r instanceof Local) {
                    DalvikTyper.v().addConstraint(stmt.getLeftOpBox(), stmt.getRightOpBox());
                    return;
                }
                if (stmt.containsInvokeExpr()) {
                    DalvikTyper.v().setInvokeType(stmt.getInvokeExpr());
                }
                if (r instanceof Local) {
                    // l NOT local
                    Type leftType = stmt.getLeftOp().getType();
                    if (l instanceof ArrayRef && leftType instanceof UnknownType) {
                        // find type later
                        todoUnits.add(stmt);
                        return;
                    }
                    DalvikTyper.v().setType(stmt.getRightOpBox(), leftType, true);
                    return;
                }
                if (l instanceof Local) {
                    if (r instanceof UntypedConstant)
                        return;
                    for (Tag t : stmt.getTags()) {
                        if (r instanceof CastExpr) {
                            // do not check tag, since the tag is for the operand of the cast
                            break;
                        }
                        // Debug.printDbg("assign stmt tag: ", stmt, t);
                        if (t instanceof IntOpTag) {
                            checkExpr(r, IntType.v());
                            DalvikTyper.v().setType(stmt.getLeftOpBox(), IntType.v(), false);
                            return;
                        } else if (t instanceof FloatOpTag) {
                            checkExpr(r, FloatType.v());
                            DalvikTyper.v().setType(stmt.getLeftOpBox(), FloatType.v(), false);
                            return;
                        } else if (t instanceof DoubleOpTag) {
                            checkExpr(r, DoubleType.v());
                            DalvikTyper.v().setType(stmt.getLeftOpBox(), DoubleType.v(), false);
                            return;
                        } else if (t instanceof LongOpTag) {
                            checkExpr(r, LongType.v());
                            DalvikTyper.v().setType(stmt.getLeftOpBox(), LongType.v(), false);
                            return;
                        }
                    }
                    Type rightType = stmt.getRightOp().getType();
                    if (r instanceof ArrayRef && rightType instanceof UnknownType) {
                        // find type later
                        todoUnits.add(stmt);
                        return;
                    } else if (r instanceof CastExpr) {
                        CastExpr ce = (CastExpr) r;
                        Type castType = ce.getCastType();
                        if (castType instanceof PrimType) {
                            // check incoming primitive type
                            for (Tag t : stmt.getTags()) {
                                // Debug.printDbg("assign primitive type from stmt tag: ", stmt, t);
                                if (t instanceof IntOpTag) {
                                    DalvikTyper.v().setType(ce.getOpBox(), IntType.v(), false);
                                    return;
                                } else if (t instanceof FloatOpTag) {
                                    DalvikTyper.v().setType(ce.getOpBox(), FloatType.v(), false);
                                    return;
                                } else if (t instanceof DoubleOpTag) {
                                    DalvikTyper.v().setType(ce.getOpBox(), DoubleType.v(), false);
                                    return;
                                } else if (t instanceof LongOpTag) {
                                    DalvikTyper.v().setType(ce.getOpBox(), LongType.v(), false);
                                    return;
                                }
                            }
                        } else {
                            // incoming type is object
                            DalvikTyper.v().setType(ce.getOpBox(), RefType.v("java.lang.Object"), false);
                        }
                    }
                    DalvikTyper.v().setType(stmt.getLeftOpBox(), rightType, false);
                    return;
                }
            }

            @Override
            public void caseIdentityStmt(IdentityStmt stmt) {
                DalvikTyper.v().setType(stmt.getLeftOpBox(), stmt.getRightOp().getType(), false);
            }

            @Override
            public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getOpBox(), RefType.v("java.lang.Object"), true);
            }

            @Override
            public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getOpBox(), RefType.v("java.lang.Object"), true);
            }

            @Override
            public void caseGotoStmt(GotoStmt stmt) {
            // nothing
            }

            @Override
            public void caseIfStmt(IfStmt stmt) {
                // add constraint
                Value c = stmt.getCondition();
                if (c instanceof BinopExpr) {
                    BinopExpr bo = (BinopExpr) c;
                    Value op1 = bo.getOp1();
                    Value op2 = bo.getOp2();
                    if (op1 instanceof Local && op2 instanceof Local) {
                        DalvikTyper.v().addConstraint(bo.getOp1Box(), bo.getOp2Box());
                    }
                }
            }

            @Override
            public void caseLookupSwitchStmt(LookupSwitchStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getKeyBox(), IntType.v(), true);
            }

            @Override
            public void caseNopStmt(NopStmt stmt) {
            // nothing
            }

            @Override
            public void caseRetStmt(RetStmt stmt) {
            // nothing
            }

            @Override
            public void caseReturnStmt(ReturnStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getOpBox(), b.getMethod().getReturnType(), true);
            }

            @Override
            public void caseReturnVoidStmt(ReturnVoidStmt stmt) {
            // nothing
            }

            @Override
            public void caseTableSwitchStmt(TableSwitchStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getKeyBox(), IntType.v(), true);
            }

            @Override
            public void caseThrowStmt(ThrowStmt stmt) {
                // add constraint
                DalvikTyper.v().setType(stmt.getOpBox(), RefType.v("java.lang.Object"), true);
            }

            @Override
            public void defaultCase(Object obj) {
                throw new RuntimeException("error: unknown statement: " + obj);
            }
        };
        u.apply(ss);
    }
    // <com.admob.android.ads.q: void a(android.os.Bundle,java.lang.String,java.lang.Object)>
    if (!todoUnits.isEmpty()) {
        // propagate array types
        UnitGraph ug = new ExceptionalUnitGraph(b);
        SimpleLocalDefs sld = new SimpleLocalDefs(ug);
        SimpleLocalUses slu = new SimpleLocalUses(b, sld);
        for (Unit u : b.getUnits()) {
            if (u instanceof DefinitionStmt) {
                // Debug.printDbg("U: ", u);
                DefinitionStmt ass = (DefinitionStmt) u;
                Value r = ass.getRightOp();
                if (r instanceof UntypedConstant)
                    continue;
                Type rType = r.getType();
                if (rType instanceof ArrayType && ass.getLeftOp() instanceof Local) {
                    // Debug.printDbg("propagate-array: checking ", u);
                    // propagate array type through aliases
                    Set<Unit> done = new HashSet<Unit>();
                    Set<DefinitionStmt> toDo = new HashSet<DefinitionStmt>();
                    toDo.add(ass);
                    while (!toDo.isEmpty()) {
                        DefinitionStmt currentUnit = toDo.iterator().next();
                        if (done.contains(currentUnit)) {
                            toDo.remove(currentUnit);
                            continue;
                        }
                        done.add(currentUnit);
                        for (UnitValueBoxPair uvbp : slu.getUsesOf(currentUnit)) {
                            Unit use = uvbp.unit;
                            Value l2 = null;
                            Value r2 = null;
                            if (use instanceof AssignStmt) {
                                AssignStmt ass2 = (AssignStmt) use;
                                l2 = ass2.getLeftOp();
                                r2 = ass2.getRightOp();
                                if (!(l2 instanceof Local) || !(r2 instanceof Local || r2 instanceof ArrayRef)) {
                                    // Debug.printDbg("propagate-array: skipping ", use);
                                    continue;
                                }
                                Type newType = null;
                                if (r2 instanceof Local) {
                                    List<LocalObj> lobjs = local2Obj.get(r2);
                                    newType = lobjs.get(0).t;
                                } else if (r2 instanceof ArrayRef) {
                                    ArrayRef ar = (ArrayRef) r2;
                                    // skip if use is in index
                                    if (ar.getIndex() == currentUnit.getLeftOp()) {
                                        // Debug.printDbg("skipping since local is used as index...");
                                        continue;
                                    }
                                    Local arBase = (Local) ar.getBase();
                                    List<LocalObj> lobjs = local2Obj.get(arBase);
                                    Type baseT = lobjs.get(0).t;
                                    if (baseT.toString().equals(("java.lang.Object"))) {
                                        // look for an array type, because an TTT[] is also an Object...
                                        ArrayType aTypeOtherThanObject = null;
                                        for (LocalObj lo : local2Obj.get(arBase)) {
                                            if (lo.t instanceof ArrayType) {
                                                aTypeOtherThanObject = (ArrayType) lo.t;
                                            }
                                        }
                                        if (aTypeOtherThanObject == null) {
                                            throw new RuntimeException("error: did not found array type for base " + arBase + " " + local2Obj.get(arBase) + " \n " + b);
                                        }
                                        baseT = aTypeOtherThanObject;
                                    }
                                    ArrayType at = (ArrayType) baseT;
                                    newType = at.getElementType();
                                } else {
                                    throw new RuntimeException("error: expected Local or ArrayRef. Got " + r2);
                                }
                                toDo.add((DefinitionStmt) use);
                                DalvikTyper.v().setType(ass2.getLeftOpBox(), newType, true);
                            }
                        }
                    }
                }
            }
        }
        for (Unit u : todoUnits) {
        // Debug.printDbg("todo unit: ", u);
        }
        while (!todoUnits.isEmpty()) {
            Unit u = todoUnits.iterator().next();
            if (!(u instanceof AssignStmt)) {
                throw new RuntimeException("error: expecting assign stmt. Got " + u);
            }
            AssignStmt ass = (AssignStmt) u;
            Value l = ass.getLeftOp();
            Value r = ass.getRightOp();
            ArrayRef ar = null;
            Local loc = null;
            if (l instanceof ArrayRef) {
                ar = (ArrayRef) l;
                loc = (Local) r;
            } else if (r instanceof ArrayRef) {
                ar = (ArrayRef) r;
                loc = (Local) l;
            } else {
                throw new RuntimeException("error: expecting an array ref. Got " + u);
            }
            Local baselocal = (Local) ar.getBase();
            if (!local2Obj.containsKey(baselocal)) {
                // Debug.printDbg("b: ", b.getMethod(), " \n", b);
                throw new RuntimeException("oups");
            }
            Type baseT = local2Obj.get(baselocal).get(0).t;
            if (baseT.toString().equals(("java.lang.Object"))) {
                // look for an array type, because an TTT[] is also an Object...
                ArrayType aTypeOtherThanObject = null;
                for (LocalObj lo : local2Obj.get(baselocal)) {
                    if (lo.t instanceof ArrayType) {
                        aTypeOtherThanObject = (ArrayType) lo.t;
                    }
                }
                if (aTypeOtherThanObject == null) {
                    throw new RuntimeException("did not found array type for base " + baselocal + " " + local2Obj.get(baselocal) + " \n " + b);
                }
                baseT = aTypeOtherThanObject;
            }
            ArrayType basetype = (ArrayType) baseT;
            // Debug.printDbg("v: ", ar, " base:", ar.getBase(), " base type: ", basetype, " type: ", ar.getType());
            Type t = basetype.getElementType();
            if (t instanceof UnknownType) {
                todoUnits.add(u);
                continue;
            } else {
                DalvikTyper.v().setType(ar == l ? ass.getRightOpBox() : ass.getLeftOpBox(), t, true);
                todoUnits.remove(u);
            }
        }
    // throw new RuntimeException("ouppppp");
    }
    // Debug.printDbg(IDalvikTyper.DEBUG, "list of constraints:");
    List<ValueBox> vbList = b.getUseAndDefBoxes();
    // clear constraints after local splitting and dead code eliminator
    List<Constraint> toRemove = new ArrayList<Constraint>();
    for (Constraint c : constraints) {
        if (!vbList.contains(c.l)) {
            // Debug.printDbg(IDalvikTyper.DEBUG, "warning: ", c.l, " not in locals! removing...");
            toRemove.add(c);
            continue;
        }
        if (!vbList.contains(c.r)) {
            // Debug.printDbg(IDalvikTyper.DEBUG, "warning: ", c.r, " not in locals! removing...");
            toRemove.add(c);
            continue;
        }
    }
    for (Constraint c : toRemove) constraints.remove(c);
    // keep only valid locals
    for (LocalObj lo : localObjList) {
        if (!vbList.contains(lo.vb)) {
            // Debug.printDbg(IDalvikTyper.DEBUG, "  -- removing vb: ", lo.vb, " with type ", lo.t);
            continue;
        }
        Local l = lo.getLocal();
        Type t = lo.t;
        if (localTemp.contains(l) && lo.isUse) {
        // Debug.printDbg(IDalvikTyper.DEBUG, "  /!\\ def already added for local ", l, "! for vb: ", lo.vb);
        } else {
            // Debug.printDbg(IDalvikTyper.DEBUG, "  * add type ", t, " to local ", l, " for vb: ", lo.vb);
            localTemp.add(l);
            typed.put(lo.vb, t);
        }
    }
    for (ValueBox vb : typed.keySet()) {
        if (vb.getValue() instanceof Local) {
            Local l = (Local) vb.getValue();
            localTyped.put(l, typed.get(vb));
        }
    }
    for (Constraint c : constraints) // Debug.printDbg(IDalvikTyper.DEBUG, "  -> constraint: ", c);
    for (ValueBox vb : typed.keySet()) {
    // Debug.printDbg(IDalvikTyper.DEBUG, "    typed: ", vb, " -> ", typed.get(vb));
    }
    for (Local l : localTyped.keySet()) {
    // Debug.printDbg(IDalvikTyper.DEBUG, "    localTyped: ", l, " -> ", localTyped.get(l));
    }
    while (!constraints.isEmpty()) {
        boolean update = false;
        for (Constraint c : constraints) {
            // Debug.printDbg(IDalvikTyper.DEBUG, "current constraint: ", c);
            Value l = c.l.getValue();
            Value r = c.r.getValue();
            if (l instanceof Local && r instanceof Constant) {
                Constant cst = (Constant) r;
                if (!localTyped.containsKey(l))
                    continue;
                Type lt = localTyped.get(l);
                // Debug.printDbg(IDalvikTyper.DEBUG, "would like to set type ", lt, " to constant: ", c);
                Value newValue = null;
                if (lt instanceof IntType || lt instanceof BooleanType || lt instanceof ShortType || lt instanceof CharType || lt instanceof ByteType) {
                    UntypedIntOrFloatConstant uf = (UntypedIntOrFloatConstant) cst;
                    newValue = uf.toIntConstant();
                } else if (lt instanceof FloatType) {
                    UntypedIntOrFloatConstant uf = (UntypedIntOrFloatConstant) cst;
                    newValue = uf.toFloatConstant();
                } else if (lt instanceof DoubleType) {
                    UntypedLongOrDoubleConstant ud = (UntypedLongOrDoubleConstant) cst;
                    newValue = ud.toDoubleConstant();
                } else if (lt instanceof LongType) {
                    UntypedLongOrDoubleConstant ud = (UntypedLongOrDoubleConstant) cst;
                    newValue = ud.toLongConstant();
                } else {
                    if (cst instanceof UntypedIntOrFloatConstant && ((UntypedIntOrFloatConstant) cst).value == 0) {
                        newValue = NullConstant.v();
                    // Debug.printDbg("new null constant for constraint ", c, " with l type: ", localTyped.get(l));
                    } else {
                        throw new RuntimeException("unknow type for constance: " + lt);
                    }
                }
                c.r.setValue(newValue);
                // Debug.printDbg(IDalvikTyper.DEBUG, "remove constraint: ", c);
                constraints.remove(c);
                update = true;
                break;
            } else if (l instanceof Local && r instanceof Local) {
                Local leftLocal = (Local) l;
                Local rightLocal = (Local) r;
                if (localTyped.containsKey(leftLocal)) {
                    Type leftLocalType = localTyped.get(leftLocal);
                    if (!localTyped.containsKey(rightLocal)) {
                        // Debug.printDbg(IDalvikTyper.DEBUG, "set type ", leftLocalType, " to local ", rightLocal);
                        rightLocal.setType(leftLocalType);
                        setLocalTyped(rightLocal, leftLocalType);
                    }
                    // Debug.printDbg(IDalvikTyper.DEBUG, "remove constraint: ", c);
                    constraints.remove(c);
                    update = true;
                    break;
                } else if (localTyped.containsKey(rightLocal)) {
                    Type rightLocalType = localTyped.get(rightLocal);
                    if (!localTyped.containsKey(leftLocal)) {
                        // Debug.printDbg(IDalvikTyper.DEBUG, "set type ", rightLocalType, " to local ", leftLocal);
                        leftLocal.setType(rightLocalType);
                        setLocalTyped(leftLocal, rightLocalType);
                    }
                    // Debug.printDbg(IDalvikTyper.DEBUG, "remove constraint: ", c);
                    constraints.remove(c);
                    update = true;
                    break;
                }
            } else if (l instanceof ArrayRef && r instanceof Local) {
                Local rightLocal = (Local) r;
                ArrayRef ar = (ArrayRef) l;
                Local base = (Local) ar.getBase();
                // Debug.printDbg(IDalvikTyper.DEBUG, "index: ", ar.getIndex());
                if (localTyped.containsKey(base)) {
                    Type t = localTyped.get(base);
                    // Debug.printDbg(IDalvikTyper.DEBUG, "type of local1: ", t, " ", t.getClass());
                    Type elementType = null;
                    if (t instanceof ArrayType) {
                        ArrayType at = (ArrayType) t;
                        elementType = at.getArrayElementType();
                    } else {
                        continue;
                    }
                    if (!localTyped.containsKey(rightLocal)) {
                        // Debug.printDbg(IDalvikTyper.DEBUG, "set type ", elementType, " to local ", r);
                        rightLocal.setType(elementType);
                        setLocalTyped(rightLocal, elementType);
                    }
                    // Debug.printDbg(IDalvikTyper.DEBUG, "remove constraint: ", c);
                    constraints.remove(c);
                    update = true;
                    break;
                }
            } else if (l instanceof Local && r instanceof ArrayRef) {
                Local leftLocal = (Local) l;
                ArrayRef ar = (ArrayRef) r;
                Local base = (Local) ar.getBase();
                if (localTyped.containsKey(base)) {
                    Type t = localTyped.get(base);
                    // Debug.printDbg(IDalvikTyper.DEBUG, "type of local2: ", t, " ", t.getClass());
                    Type elementType = null;
                    if (t instanceof ArrayType) {
                        ArrayType at = (ArrayType) t;
                        elementType = at.getArrayElementType();
                    } else {
                        continue;
                    }
                    if (!localTyped.containsKey(leftLocal)) {
                        // Debug.printDbg(IDalvikTyper.DEBUG, "set type ", elementType, " to local ", l);
                        leftLocal.setType(elementType);
                        setLocalTyped(leftLocal, elementType);
                    }
                    // Debug.printDbg(IDalvikTyper.DEBUG, "remove constraint: ", c);
                    constraints.remove(c);
                    update = true;
                    break;
                }
            } else {
                throw new RuntimeException("error: do not handling this kind of constraint: " + c);
            }
        }
        if (!update)
            break;
    }
    for (Unit u : b.getUnits()) {
        if (!(u instanceof AssignStmt))
            continue;
        AssignStmt ass = (AssignStmt) u;
        if (!(ass.getLeftOp() instanceof Local))
            continue;
        if (!(ass.getRightOp() instanceof UntypedConstant))
            continue;
        UntypedConstant uc = (UntypedConstant) ass.getRightOp();
        ass.setRightOp(uc.defineType(localTyped.get(ass.getLeftOp())));
    }
    // 
    for (Constraint c : constraints) {
        // Debug.printDbg(IDalvikTyper.DEBUG, "current constraint: ", c);
        Value l = c.l.getValue();
        Value r = c.r.getValue();
        if (l instanceof Local && r instanceof Constant) {
            if (r instanceof UntypedIntOrFloatConstant) {
                UntypedIntOrFloatConstant cst = (UntypedIntOrFloatConstant) r;
                Value newValue = null;
                if (cst.value != 0) {
                    // Debug.printDbg(IDalvikTyper.DEBUG, "[untyped constaints] set type int to non zero constant: ", c, " = ", cst.value);
                    newValue = cst.toIntConstant();
                } else {
                    // check if used in cast, just in case...
                    for (Unit u : b.getUnits()) {
                        for (ValueBox vb1 : u.getUseBoxes()) {
                            Value v1 = vb1.getValue();
                            if (v1 == l) {
                                // Debug.printDbg("local used in ", u);
                                if (u instanceof AssignStmt) {
                                    AssignStmt a = (AssignStmt) u;
                                    Value right = a.getRightOp();
                                    if (right instanceof CastExpr) {
                                        newValue = NullConstant.v();
                                    } else {
                                        newValue = cst.toIntConstant();
                                    }
                                } else if (u instanceof IfStmt) {
                                    // TODO check this better
                                    newValue = cst.toIntConstant();
                                }
                            }
                        }
                    }
                }
                if (newValue == null) {
                    throw new RuntimeException("error: no type found for local: " + l);
                }
                c.r.setValue(newValue);
            } else if (r instanceof UntypedLongOrDoubleConstant) {
                // Debug.printDbg(IDalvikTyper.DEBUG, "[untyped constaints] set type long to constant: ", c);
                Value newValue = ((UntypedLongOrDoubleConstant) r).toLongConstant();
                c.r.setValue(newValue);
            }
        }
    }
    // fix untypedconstants which have flown to an array index
    for (Unit u : b.getUnits()) {
        StmtSwitch sw = new StmtSwitch() {

            @Override
            public void caseBreakpointStmt(BreakpointStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseInvokeStmt(InvokeStmt stmt) {
                changeUntypedConstantsInInvoke(stmt.getInvokeExpr());
            }

            @Override
            public void caseAssignStmt(AssignStmt stmt) {
                if (stmt.getRightOp() instanceof NewArrayExpr) {
                    NewArrayExpr nae = (NewArrayExpr) stmt.getRightOp();
                    if (nae.getSize() instanceof UntypedConstant) {
                        UntypedIntOrFloatConstant uc = (UntypedIntOrFloatConstant) nae.getSize();
                        nae.setSize(uc.defineType(IntType.v()));
                    }
                } else if (stmt.getRightOp() instanceof UntypedConstant) {
                    UntypedConstant uc = (UntypedConstant) stmt.getRightOp();
                    Value l = stmt.getLeftOp();
                    Type lType = null;
                    if (l instanceof ArrayRef) {
                        ArrayRef ar = (ArrayRef) l;
                        Local baseLocal = (Local) ar.getBase();
                        ArrayType arrayType = (ArrayType) localTyped.get(baseLocal);
                        lType = arrayType.getElementType();
                    } else {
                        lType = l.getType();
                    }
                    stmt.setRightOp(uc.defineType(lType));
                } else if (stmt.getRightOp() instanceof InvokeExpr) {
                    changeUntypedConstantsInInvoke((InvokeExpr) stmt.getRightOp());
                }
                if (!stmt.containsArrayRef()) {
                    return;
                }
                ArrayRef ar = stmt.getArrayRef();
                if ((ar.getIndex() instanceof UntypedConstant)) {
                    UntypedIntOrFloatConstant uc = (UntypedIntOrFloatConstant) ar.getIndex();
                    ar.setIndex(uc.toIntConstant());
                }
                if (stmt.getLeftOp() instanceof ArrayRef && stmt.getRightOp() instanceof UntypedConstant) {
                    UntypedConstant uc = (UntypedConstant) stmt.getRightOp();
                    Local baseLocal = (Local) stmt.getArrayRef().getBase();
                    ArrayType lType = (ArrayType) localTyped.get(baseLocal);
                    Type elemType = lType.getElementType();
                    stmt.setRightOp(uc.defineType(elemType));
                }
            }

            @Override
            public void caseIdentityStmt(IdentityStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseGotoStmt(GotoStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseIfStmt(IfStmt stmt) {
                Value c = stmt.getCondition();
                if (c instanceof BinopExpr) {
                    BinopExpr be = (BinopExpr) c;
                    Value op1 = be.getOp1();
                    Value op2 = be.getOp2();
                    if (op1 instanceof UntypedConstant || op2 instanceof UntypedConstant) {
                        if (op1 instanceof Local) {
                            Type t = localTyped.get(op1);
                            // Debug.printDbg("if op1 type: ", t);
                            UntypedConstant uc = (UntypedConstant) op2;
                            be.setOp2(uc.defineType(t));
                        } else if (op2 instanceof Local) {
                            Type t = localTyped.get(op2);
                            // Debug.printDbg("if op2 type: ", t);
                            UntypedConstant uc = (UntypedConstant) op1;
                            be.setOp1(uc.defineType(t));
                        } else if (op1 instanceof UntypedConstant && op2 instanceof UntypedConstant) {
                            if (op1 instanceof UntypedIntOrFloatConstant && op2 instanceof UntypedIntOrFloatConstant) {
                                UntypedIntOrFloatConstant uc1 = (UntypedIntOrFloatConstant) op1;
                                UntypedIntOrFloatConstant uc2 = (UntypedIntOrFloatConstant) op2;
                                // to int or float, it does not matter
                                be.setOp1(uc1.toIntConstant());
                                be.setOp2(uc2.toIntConstant());
                            } else if (op1 instanceof UntypedLongOrDoubleConstant && op2 instanceof UntypedLongOrDoubleConstant) {
                                UntypedLongOrDoubleConstant uc1 = (UntypedLongOrDoubleConstant) op1;
                                UntypedLongOrDoubleConstant uc2 = (UntypedLongOrDoubleConstant) op2;
                                // to long or double, it does not matter
                                be.setOp1(uc1.toLongConstant());
                                be.setOp2(uc2.toLongConstant());
                            } else {
                                throw new RuntimeException("error: expected same type of untyped constants. Got " + stmt);
                            }
                        } else if (op1 instanceof UntypedConstant || op2 instanceof UntypedConstant) {
                            if (op1 instanceof UntypedConstant) {
                                UntypedConstant uc = (UntypedConstant) op1;
                                be.setOp1(uc.defineType(op2.getType()));
                            } else if (op2 instanceof UntypedConstant) {
                                UntypedConstant uc = (UntypedConstant) op2;
                                be.setOp2(uc.defineType(op1.getType()));
                            }
                        } else {
                            throw new RuntimeException("error: expected local/untyped untyped/local or untyped/untyped. Got " + stmt);
                        }
                    }
                } else if (c instanceof UnopExpr) {
                } else {
                    throw new RuntimeException("error: expected binop or unop. Got " + stmt);
                }
            }

            @Override
            public void caseLookupSwitchStmt(LookupSwitchStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseNopStmt(NopStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseRetStmt(RetStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseReturnStmt(ReturnStmt stmt) {
                if (stmt.getOp() instanceof UntypedConstant) {
                    UntypedConstant uc = (UntypedConstant) stmt.getOp();
                    Type type = b.getMethod().getReturnType();
                    stmt.setOp(uc.defineType(type));
                }
            }

            @Override
            public void caseReturnVoidStmt(ReturnVoidStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseTableSwitchStmt(TableSwitchStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void caseThrowStmt(ThrowStmt stmt) {
            // TODO Auto-generated method stub
            }

            @Override
            public void defaultCase(Object obj) {
            // TODO Auto-generated method stub
            }
        };
        u.apply(sw);
    }
// fix untyped constants remaining
// Debug.printDbg("assignTypes: after: \n", b);
}

Example 3 with UnknownType

use of soot.UnknownType in project soot by Sable.

the class DalvikTyper method setType.

@Override
public void setType(ValueBox vb, Type t, boolean isUse) {
    if (IDalvikTyper.DEBUG)
        if (t instanceof UnknownType) {
            throw new RuntimeException("error: expected concreted type. Got " + t);
        }
    if (vb.getValue() instanceof Local) {
        LocalObj lb = new LocalObj(vb, t, isUse);
        localObjList.add(lb);
        Local k = (Local) vb.getValue();
        if (!local2Obj.containsKey(k)) {
            local2Obj.put(k, new ArrayList<LocalObj>());
        }
        local2Obj.get(k).add(lb);
    } else {
    // Debug.printDbg(IDalvikTyper.DEBUG, "not instance of local: vb: ", vb, " value: ", vb.getValue(), " class: ", vb.getValue().getClass());
    }
}

Example 4 with UnknownType

use of soot.UnknownType in project soot by Sable.

the class DexNumTransformer method internalTransform.

@Override
protected void internalTransform(final Body body, String phaseName, Map<String, String> options) {
    final DexDefUseAnalysis localDefs = new DexDefUseAnalysis(body);
    for (Local loc : getNumCandidates(body)) {
        usedAsFloatingPoint = false;
        Set<Unit> defs = localDefs.collectDefinitionsWithAliases(loc);
        // process normally
        doBreak = false;
        for (Unit u : defs) {
            // put correct local in l
            final Local l = u instanceof DefinitionStmt ? (Local) ((DefinitionStmt) u).getLeftOp() : null;
            // check defs
            u.apply(new AbstractStmtSwitch() {

                @Override
                public void caseAssignStmt(AssignStmt stmt) {
                    Value r = stmt.getRightOp();
                    if (r instanceof BinopExpr && !(r instanceof CmpExpr)) {
                        usedAsFloatingPoint = examineBinopExpr(stmt);
                        doBreak = true;
                    } else if (r instanceof FieldRef) {
                        usedAsFloatingPoint = isFloatingPointLike(((FieldRef) r).getFieldRef().type());
                        doBreak = true;
                    } else if (r instanceof NewArrayExpr) {
                        NewArrayExpr nae = (NewArrayExpr) r;
                        Type t = nae.getType();
                        usedAsFloatingPoint = isFloatingPointLike(t);
                        doBreak = true;
                    } else if (r instanceof ArrayRef) {
                        ArrayRef ar = (ArrayRef) r;
                        Type arType = ar.getType();
                        if (arType instanceof UnknownType) {
                            Type t = findArrayType(localDefs, stmt, 0, // TODO:
                            Collections.<Unit>emptySet());
                            // check
                            // where
                            // else
                            // to
                            // update
                            // if(ArrayRef...
                            usedAsFloatingPoint = isFloatingPointLike(t);
                        } else {
                            usedAsFloatingPoint = isFloatingPointLike(ar.getType());
                        }
                        doBreak = true;
                    } else if (r instanceof CastExpr) {
                        usedAsFloatingPoint = isFloatingPointLike(((CastExpr) r).getCastType());
                        doBreak = true;
                    } else if (r instanceof InvokeExpr) {
                        usedAsFloatingPoint = isFloatingPointLike(((InvokeExpr) r).getType());
                        doBreak = true;
                    } else if (r instanceof LengthExpr) {
                        usedAsFloatingPoint = false;
                        doBreak = true;
                    }
                }

                @Override
                public void caseIdentityStmt(IdentityStmt stmt) {
                    if (stmt.getLeftOp() == l) {
                        usedAsFloatingPoint = isFloatingPointLike(stmt.getRightOp().getType());
                        doBreak = true;
                    }
                }
            });
            if (doBreak) {
                break;
            }
            // check uses
            for (Unit use : localDefs.getUsesOf(l)) {
                use.apply(new AbstractStmtSwitch() {

                    private boolean examineInvokeExpr(InvokeExpr e) {
                        List<Value> args = e.getArgs();
                        List<Type> argTypes = e.getMethodRef().parameterTypes();
                        assert args.size() == argTypes.size();
                        for (int i = 0; i < args.size(); i++) {
                            if (args.get(i) == l && isFloatingPointLike(argTypes.get(i))) {
                                return true;
                            }
                        }
                        return false;
                    }

                    @Override
                    public void caseInvokeStmt(InvokeStmt stmt) {
                        InvokeExpr e = stmt.getInvokeExpr();
                        usedAsFloatingPoint = examineInvokeExpr(e);
                    }

                    @Override
                    public void caseAssignStmt(AssignStmt stmt) {
                        // only case where 'l' could be on the left side is
                        // arrayRef with 'l' as the index
                        Value left = stmt.getLeftOp();
                        if (left instanceof ArrayRef) {
                            ArrayRef ar = (ArrayRef) left;
                            if (ar.getIndex() == l) {
                                doBreak = true;
                                return;
                            }
                        }
                        // from this point, we only check the right hand
                        // side of the assignment
                        Value r = stmt.getRightOp();
                        if (r instanceof ArrayRef) {
                            if (((ArrayRef) r).getIndex() == l) {
                                doBreak = true;
                                return;
                            }
                        } else if (r instanceof InvokeExpr) {
                            usedAsFloatingPoint = examineInvokeExpr((InvokeExpr) r);
                            doBreak = true;
                            return;
                        } else if (r instanceof BinopExpr) {
                            usedAsFloatingPoint = examineBinopExpr(stmt);
                            doBreak = true;
                            return;
                        } else if (r instanceof CastExpr) {
                            usedAsFloatingPoint = stmt.hasTag("FloatOpTag") || stmt.hasTag("DoubleOpTag");
                            doBreak = true;
                            return;
                        } else if (r instanceof Local && r == l) {
                            if (left instanceof FieldRef) {
                                FieldRef fr = (FieldRef) left;
                                if (isFloatingPointLike(fr.getType())) {
                                    usedAsFloatingPoint = true;
                                }
                                doBreak = true;
                                return;
                            } else if (left instanceof ArrayRef) {
                                ArrayRef ar = (ArrayRef) left;
                                Type arType = ar.getType();
                                if (arType instanceof UnknownType) {
                                    arType = findArrayType(localDefs, stmt, 0, Collections.<Unit>emptySet());
                                }
                                usedAsFloatingPoint = isFloatingPointLike(arType);
                                doBreak = true;
                                return;
                            }
                        }
                    }

                    @Override
                    public void caseReturnStmt(ReturnStmt stmt) {
                        usedAsFloatingPoint = stmt.getOp() == l && isFloatingPointLike(body.getMethod().getReturnType());
                        doBreak = true;
                        return;
                    }
                });
                if (doBreak)
                    break;
            }
            // for uses
            if (doBreak)
                break;
        }
        // change values
        if (usedAsFloatingPoint) {
            for (Unit u : defs) {
                replaceWithFloatingPoint(u);
            }
        }
    // end if
    }
}

Example 5 with UnknownType

use of soot.UnknownType in project soot by Sable.

the class DexNullTransformer method internalTransform.

@Override
protected void internalTransform(final Body body, String phaseName, Map<String, String> options) {
    final DexDefUseAnalysis localDefs = new DexDefUseAnalysis(body);
    AbstractStmtSwitch checkDef = new // Alex: should also end as
    AbstractStmtSwitch() {

        // soon as detected as not
        // used as an object
        @Override
        public void caseAssignStmt(AssignStmt stmt) {
            Value r = stmt.getRightOp();
            if (r instanceof FieldRef) {
                usedAsObject = isObject(((FieldRef) r).getFieldRef().type());
                doBreak = true;
                return;
            } else if (r instanceof ArrayRef) {
                ArrayRef ar = (ArrayRef) r;
                if (ar.getType() instanceof UnknownType) {
                    // isObject
                    usedAsObject = stmt.hasTag("ObjectOpTag");
                // (findArrayType
                // (g,
                // localDefs,
                // localUses,
                // stmt));
                } else {
                    usedAsObject = isObject(ar.getType());
                }
                doBreak = true;
                return;
            } else if (r instanceof StringConstant || r instanceof NewExpr || r instanceof NewArrayExpr) {
                usedAsObject = true;
                doBreak = true;
                return;
            } else if (r instanceof CastExpr) {
                usedAsObject = isObject(((CastExpr) r).getCastType());
                doBreak = true;
                return;
            } else if (r instanceof InvokeExpr) {
                usedAsObject = isObject(((InvokeExpr) r).getType());
                doBreak = true;
                return;
            } else if (r instanceof LengthExpr) {
                usedAsObject = false;
                doBreak = true;
                return;
            // introduces alias
            }
        }

        @Override
        public void caseIdentityStmt(IdentityStmt stmt) {
            if (stmt.getLeftOp() == l) {
                usedAsObject = isObject(stmt.getRightOp().getType());
                doBreak = true;
                return;
            }
        }
    };
    AbstractStmtSwitch checkUse = new AbstractStmtSwitch() {

        private boolean examineInvokeExpr(InvokeExpr e) {
            List<Value> args = e.getArgs();
            List<Type> argTypes = e.getMethodRef().parameterTypes();
            assert args.size() == argTypes.size();
            for (int i = 0; i < args.size(); i++) {
                if (args.get(i) == l && isObject(argTypes.get(i))) {
                    return true;
                }
            }
            // check for base
            SootMethodRef sm = e.getMethodRef();
            if (!sm.isStatic()) {
                if (e instanceof AbstractInvokeExpr) {
                    AbstractInstanceInvokeExpr aiiexpr = (AbstractInstanceInvokeExpr) e;
                    Value b = aiiexpr.getBase();
                    if (b == l) {
                        return true;
                    }
                }
            }
            return false;
        }

        @Override
        public void caseInvokeStmt(InvokeStmt stmt) {
            InvokeExpr e = stmt.getInvokeExpr();
            usedAsObject = examineInvokeExpr(e);
            doBreak = true;
            return;
        }

        @Override
        public void caseAssignStmt(AssignStmt stmt) {
            Value left = stmt.getLeftOp();
            Value r = stmt.getRightOp();
            if (left instanceof ArrayRef) {
                ArrayRef ar = (ArrayRef) left;
                if (ar.getIndex() == l) {
                    doBreak = true;
                    return;
                } else if (ar.getBase() == l) {
                    usedAsObject = true;
                    doBreak = true;
                    return;
                }
            }
            if (left instanceof InstanceFieldRef) {
                InstanceFieldRef ifr = (InstanceFieldRef) left;
                if (ifr.getBase() == l) {
                    usedAsObject = true;
                    doBreak = true;
                    return;
                }
            }
            // used to assign
            if (stmt.getRightOp() == l) {
                Value l = stmt.getLeftOp();
                if (l instanceof StaticFieldRef && isObject(((StaticFieldRef) l).getFieldRef().type())) {
                    usedAsObject = true;
                    doBreak = true;
                    return;
                } else if (l instanceof InstanceFieldRef && isObject(((InstanceFieldRef) l).getFieldRef().type())) {
                    usedAsObject = true;
                    doBreak = true;
                    return;
                } else if (l instanceof ArrayRef) {
                    Type aType = ((ArrayRef) l).getType();
                    if (aType instanceof UnknownType) {
                        usedAsObject = stmt.hasTag(// isObject(
                        "ObjectOpTag");
                    // findArrayType(g,
                    // localDefs,
                    // localUses,
                    // stmt));
                    } else {
                        usedAsObject = isObject(aType);
                    }
                    doBreak = true;
                    return;
                }
            }
            // is used as value (does not exclude assignment)
            if (r instanceof FieldRef) {
                // isObject(((FieldRef)
                usedAsObject = true;
                // r).getFieldRef().type());
                doBreak = true;
                return;
            } else if (r instanceof ArrayRef) {
                ArrayRef ar = (ArrayRef) r;
                if (ar.getBase() == l) {
                    usedAsObject = true;
                } else {
                    // used as index
                    usedAsObject = false;
                }
                doBreak = true;
                return;
            } else if (r instanceof StringConstant || r instanceof NewExpr) {
                throw new RuntimeException("NOT POSSIBLE StringConstant or NewExpr at " + stmt);
            } else if (r instanceof NewArrayExpr) {
                usedAsObject = false;
                doBreak = true;
                return;
            } else if (r instanceof CastExpr) {
                usedAsObject = isObject(((CastExpr) r).getCastType());
                doBreak = true;
                return;
            } else if (r instanceof InvokeExpr) {
                usedAsObject = examineInvokeExpr((InvokeExpr) stmt.getRightOp());
                doBreak = true;
                return;
            } else if (r instanceof LengthExpr) {
                usedAsObject = true;
                doBreak = true;
                return;
            } else if (r instanceof BinopExpr) {
                usedAsObject = false;
                doBreak = true;
                return;
            }
        }

        @Override
        public void caseIdentityStmt(IdentityStmt stmt) {
            if (stmt.getLeftOp() == l)
                throw new RuntimeException("IMPOSSIBLE 0");
        }

        @Override
        public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
            usedAsObject = stmt.getOp() == l;
            doBreak = true;
            return;
        }

        @Override
        public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
            usedAsObject = stmt.getOp() == l;
            doBreak = true;
            return;
        }

        @Override
        public void caseReturnStmt(ReturnStmt stmt) {
            usedAsObject = stmt.getOp() == l && isObject(body.getMethod().getReturnType());
            doBreak = true;
            return;
        }

        @Override
        public void caseThrowStmt(ThrowStmt stmt) {
            usedAsObject = stmt.getOp() == l;
            doBreak = true;
            return;
        }
    };
    for (Local loc : getNullCandidates(body)) {
        usedAsObject = false;
        Set<Unit> defs = localDefs.collectDefinitionsWithAliases(loc);
        // process normally
        doBreak = false;
        for (Unit u : defs) {
            // put correct local in l
            if (u instanceof DefinitionStmt) {
                l = (Local) ((DefinitionStmt) u).getLeftOp();
            } else if (u instanceof IfStmt) {
                throw new RuntimeException("ERROR: def can not be something else than Assign or Identity statement! (def: " + u + " class: " + u.getClass() + "");
            }
            // check defs
            u.apply(checkDef);
            if (doBreak)
                break;
            // check uses
            for (Unit use : localDefs.getUsesOf(l)) {
                use.apply(checkUse);
                if (doBreak)
                    break;
            }
            // for uses
            if (doBreak)
                break;
        }
        // change values
        if (usedAsObject) {
            for (Unit u : defs) {
                replaceWithNull(u);
                Set<Value> defLocals = new HashSet<Value>();
                for (ValueBox vb : u.getDefBoxes()) defLocals.add(vb.getValue());
                Local l = (Local) ((DefinitionStmt) u).getLeftOp();
                for (Unit uuse : localDefs.getUsesOf(l)) {
                    Stmt use = (Stmt) uuse;
                    // If we have a[x] = 0 and a is an object, we may not conclude 0 -> null
                    if (!use.containsArrayRef() || !defLocals.contains(use.getArrayRef().getBase()))
                        replaceWithNull(use);
                }
            }
        }
    // end if
    }
    // Check for inlined zero values
    AbstractStmtSwitch inlinedZeroValues = new AbstractStmtSwitch() {

        final NullConstant nullConstant = NullConstant.v();

        @Override
        public void caseAssignStmt(AssignStmt stmt) {
            // Case a = 0 with a being an object
            if (isObject(stmt.getLeftOp().getType()) && isConstZero(stmt.getRightOp())) {
                stmt.setRightOp(nullConstant);
                return;
            }
            // Case a = (Object) 0
            if (stmt.getRightOp() instanceof CastExpr) {
                CastExpr ce = (CastExpr) stmt.getRightOp();
                if (isObject(ce.getCastType()) && isConstZero(ce.getOp())) {
                    stmt.setRightOp(nullConstant);
                }
            }
            // Case a[0] = 0
            if (stmt.getLeftOp() instanceof ArrayRef && isConstZero(stmt.getRightOp())) {
                ArrayRef ar = (ArrayRef) stmt.getLeftOp();
                if (isObjectArray(ar.getBase(), body) || stmt.hasTag("ObjectOpTag")) {
                    stmt.setRightOp(nullConstant);
                }
            }
        }

        private boolean isConstZero(Value rightOp) {
            if (rightOp instanceof IntConstant && ((IntConstant) rightOp).value == 0)
                return true;
            if (rightOp instanceof LongConstant && ((LongConstant) rightOp).value == 0)
                return true;
            return false;
        }

        @Override
        public void caseReturnStmt(ReturnStmt stmt) {
            if (stmt.getOp() instanceof IntConstant && isObject(body.getMethod().getReturnType())) {
                IntConstant iconst = (IntConstant) stmt.getOp();
                assert iconst.value == 0;
                stmt.setOp(nullConstant);
            }
        }

        @Override
        public void caseEnterMonitorStmt(EnterMonitorStmt stmt) {
            if (stmt.getOp() instanceof IntConstant && ((IntConstant) stmt.getOp()).value == 0)
                stmt.setOp(nullConstant);
        }

        @Override
        public void caseExitMonitorStmt(ExitMonitorStmt stmt) {
            if (stmt.getOp() instanceof IntConstant && ((IntConstant) stmt.getOp()).value == 0)
                stmt.setOp(nullConstant);
        }
    };
    final NullConstant nullConstant = NullConstant.v();
    for (Unit u : body.getUnits()) {
        u.apply(inlinedZeroValues);
        if (u instanceof Stmt) {
            Stmt stmt = (Stmt) u;
            if (stmt.containsInvokeExpr()) {
                InvokeExpr invExpr = stmt.getInvokeExpr();
                for (int i = 0; i < invExpr.getArgCount(); i++) if (isObject(invExpr.getMethodRef().parameterType(i)))
                    if (invExpr.getArg(i) instanceof IntConstant) {
                        IntConstant iconst = (IntConstant) invExpr.getArg(i);
                        assert iconst.value == 0;
                        invExpr.setArg(i, nullConstant);
                    }
            }
        }
    }
}