Examples with NewMultiArrayExpr soot.jimple.NewMultiArrayExpr used on opensource projects

Example 6 with NewMultiArrayExpr

use of soot.jimple.NewMultiArrayExpr in project soot by Sable.

the class ArrayIndexLivenessAnalysis method getGenAndKillSetForDefnStmt.

private void getGenAndKillSetForDefnStmt(DefinitionStmt asstmt, HashMap<Stmt, HashSet<Value>> absgen, HashSet<Object> genset, HashSet<Value> absgenset, HashSet<Value> killset, HashSet<Value> condset) {
    /* kill left hand side */
    Value lhs = asstmt.getLeftOp();
    Value rhs = asstmt.getRightOp();
    boolean killarrayrelated = false;
    boolean killallarrayref = false;
    if (fieldin) {
        if (lhs instanceof Local) {
            HashSet<Value> related = localToFieldRef.get(lhs);
            if (related != null)
                killset.addAll(related);
        } else if (lhs instanceof StaticFieldRef) {
            killset.add(lhs);
            condset.add(lhs);
        } else if (lhs instanceof InstanceFieldRef) {
            SootField field = ((InstanceFieldRef) lhs).getField();
            HashSet<Value> related = fieldToFieldRef.get(field);
            if (related != null)
                killset.addAll(related);
            condset.add(lhs);
        }
        if (asstmt.containsInvokeExpr()) {
            /*
                Value expr = asstmt.getInvokeExpr();
                List parameters = ((InvokeExpr)expr).getArgs();

                // add the method invocation
                boolean killall = false;
                if (expr instanceof InstanceInvokeExpr)
                    killall = true;
                else
                {
                    for (int i=0; i<parameters.size(); i++)
                    {
                    Value para = (Value)parameters.get(i);
                    if (para.getType() instanceof RefType)
                    {
                        killall = true;
                        break;
                    }
                    }
                }
    
                if (killall)
                {
                    killset.addAll(allInstFieldRefs);
                }   
                */
            killset.addAll(allFieldRefs);
        }
    }
    if (arrayin) {
        // a = ... or i = ...
        if (lhs instanceof Local) {
            killarrayrelated = true;
        } else // a[i] = ...
        if (lhs instanceof ArrayRef) {
            killallarrayref = true;
            condset.add(lhs);
        }
        // invokeexpr kills all array references.
        if (asstmt.containsInvokeExpr()) {
            killallarrayref = true;
        }
    }
    if (csin) {
        HashSet<Value> exprs = localToExpr.get(lhs);
        if (exprs != null)
            killset.addAll(exprs);
        if (rhs instanceof BinopExpr) {
            Value op1 = ((BinopExpr) rhs).getOp1();
            Value op2 = ((BinopExpr) rhs).getOp2();
            if (rhs instanceof AddExpr) {
                if ((op1 instanceof Local) && (op2 instanceof Local))
                    genset.add(rhs);
            } else if (rhs instanceof MulExpr) {
                if ((op1 instanceof Local) || (op2 instanceof Local))
                    genset.add(rhs);
            } else if (rhs instanceof SubExpr) {
                if (op2 instanceof Local)
                    genset.add(rhs);
            }
        }
    }
    if ((lhs instanceof Local) && (fullSet.contains(lhs))) {
        killset.add(lhs);
        /* speculatively add lhs as live condition. */
        condset.add(lhs);
    } else if (lhs instanceof ArrayRef) {
        /* a[i] generate a and i. */
        Value base = ((ArrayRef) lhs).getBase();
        Value index = ((ArrayRef) lhs).getIndex();
        absgenset.add(base);
        if (index instanceof Local) {
            absgenset.add(index);
        }
    }
    if (rhs instanceof Local) {
        /*
              if (lhs instanceof Local && fullSet.contains(rhs))
              genset.add(rhs);
            */
        if (fullSet.contains(rhs))
            genset.add(rhs);
    /*
              if (fieldin && (lhs instanceof FieldRef))
              genset.add(rhs);
            */
    } else if (rhs instanceof FieldRef) {
        if (fieldin)
            genset.add(rhs);
    } else if (rhs instanceof ArrayRef) {
        /* lhs=a[i]. */
        Value base = ((ArrayRef) rhs).getBase();
        Value index = ((ArrayRef) rhs).getIndex();
        absgenset.add(base);
        if (index instanceof Local) {
            absgenset.add(index);
        }
        if (arrayin) {
            genset.add(rhs);
            if (rectarray)
                genset.add(Array2ndDimensionSymbol.v(base));
        }
    } else if (rhs instanceof NewArrayExpr) {
        /* a = new A[i]; */
        Value size = ((NewArrayExpr) rhs).getSize();
        if (size instanceof Local)
            genset.add(size);
    } else if (rhs instanceof NewMultiArrayExpr) {
        /* a = new A[i][]...;*/
        /* More precisely, we should track other dimensions. */
        List sizes = ((NewMultiArrayExpr) rhs).getSizes();
        Iterator sizeIt = sizes.iterator();
        while (sizeIt.hasNext()) {
            Value size = (Value) sizeIt.next();
            if (size instanceof Local)
                genset.add(size);
        }
    } else if (rhs instanceof LengthExpr) {
        /* lhs = lengthof rhs */
        Value op = ((LengthExpr) rhs).getOp();
        genset.add(op);
    } else if (rhs instanceof JAddExpr) {
        /* lhs = rhs+c, lhs=c+rhs */
        Value op1 = ((JAddExpr) rhs).getOp1();
        Value op2 = ((JAddExpr) rhs).getOp2();
        if ((op1 instanceof IntConstant) && (op2 instanceof Local)) {
            genset.add(op2);
        } else if ((op2 instanceof IntConstant) && (op1 instanceof Local)) {
            genset.add(op1);
        }
    } else if (rhs instanceof JSubExpr) {
        Value op1 = ((JSubExpr) rhs).getOp1();
        Value op2 = ((JSubExpr) rhs).getOp2();
        if ((op1 instanceof Local) && (op2 instanceof IntConstant)) {
            genset.add(op1);
        }
    }
    if (arrayin) {
        if (killarrayrelated)
            killArrayRelated.put(asstmt, lhs);
        if (killallarrayref)
            killAllArrayRef.put(asstmt, new Boolean(true));
    }
}

Example 7 with NewMultiArrayExpr

use of soot.jimple.NewMultiArrayExpr 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 8 with NewMultiArrayExpr

use of soot.jimple.NewMultiArrayExpr in project soot by Sable.

the class NullnessAnalysis method handleRefTypeAssignment.

private void handleRefTypeAssignment(DefinitionStmt assignStmt, AnalysisInfo out) {
    Value left = assignStmt.getLeftOp();
    Value right = assignStmt.getRightOp();
    // unbox casted value
    if (right instanceof JCastExpr) {
        JCastExpr castExpr = (JCastExpr) right;
        right = castExpr.getOp();
    }
    // if we have a definition (assignment) statement to a ref-like type, handle it,
    if (isAlwaysNonNull(right) || right instanceof NewExpr || right instanceof NewArrayExpr || right instanceof NewMultiArrayExpr || right instanceof ThisRef || right instanceof StringConstant || right instanceof ClassConstant || right instanceof CaughtExceptionRef) {
        // if we assign new... or @this, the result is non-null
        out.put(left, NON_NULL);
    } else if (right == NullConstant.v()) {
        // if we assign null, well, it's null
        out.put(left, NULL);
    } else if (left instanceof Local && right instanceof Local) {
        out.put(left, out.get(right));
    } else if (left instanceof Local && right instanceof PhiExpr) {
        handlePhiExpr(out, left, (PhiExpr) right);
    } else {
        out.put(left, TOP);
    }
}

Example 9 with NewMultiArrayExpr

use of soot.jimple.NewMultiArrayExpr in project soot by Sable.

the class OnFlyCallGraphBuilder method getImplicitTargets.

private void getImplicitTargets(SootMethod source) {
    final SootClass scl = source.getDeclaringClass();
    if (source.isNative() || source.isPhantom())
        return;
    if (source.getSubSignature().indexOf("<init>") >= 0) {
        handleInit(source, scl);
    }
    Body b = source.retrieveActiveBody();
    for (Unit u : b.getUnits()) {
        final Stmt s = (Stmt) u;
        if (s.containsInvokeExpr()) {
            InvokeExpr ie = s.getInvokeExpr();
            SootMethodRef methodRef = ie.getMethodRef();
            switch(methodRef.declaringClass().getName()) {
                case "java.lang.reflect.Method":
                    if (methodRef.getSubSignature().getString().equals("java.lang.Object invoke(java.lang.Object,java.lang.Object[])"))
                        reflectionModel.methodInvoke(source, s);
                    break;
                case "java.lang.Class":
                    if (methodRef.getSubSignature().getString().equals("java.lang.Object newInstance()"))
                        reflectionModel.classNewInstance(source, s);
                    break;
                case "java.lang.reflect.Constructor":
                    if (methodRef.getSubSignature().getString().equals("java.lang.Object newInstance(java.lang.Object[]))"))
                        reflectionModel.contructorNewInstance(source, s);
                    break;
            }
            if (methodRef.getSubSignature() == sigForName) {
                reflectionModel.classForName(source, s);
            }
            if (ie instanceof StaticInvokeExpr) {
                SootClass cl = ie.getMethodRef().declaringClass();
                for (SootMethod clinit : EntryPoints.v().clinitsOf(cl)) {
                    addEdge(source, s, clinit, Kind.CLINIT);
                }
            }
        }
        if (s.containsFieldRef()) {
            FieldRef fr = s.getFieldRef();
            if (fr instanceof StaticFieldRef) {
                SootClass cl = fr.getFieldRef().declaringClass();
                for (SootMethod clinit : EntryPoints.v().clinitsOf(cl)) {
                    addEdge(source, s, clinit, Kind.CLINIT);
                }
            }
        }
        if (s instanceof AssignStmt) {
            Value rhs = ((AssignStmt) s).getRightOp();
            if (rhs instanceof NewExpr) {
                NewExpr r = (NewExpr) rhs;
                SootClass cl = r.getBaseType().getSootClass();
                for (SootMethod clinit : EntryPoints.v().clinitsOf(cl)) {
                    addEdge(source, s, clinit, Kind.CLINIT);
                }
            } else if (rhs instanceof NewArrayExpr || rhs instanceof NewMultiArrayExpr) {
                Type t = rhs.getType();
                if (t instanceof ArrayType)
                    t = ((ArrayType) t).baseType;
                if (t instanceof RefType) {
                    SootClass cl = ((RefType) t).getSootClass();
                    for (SootMethod clinit : EntryPoints.v().clinitsOf(cl)) {
                        addEdge(source, s, clinit, Kind.CLINIT);
                    }
                }
            }
        }
    }
}

Example 10 with NewMultiArrayExpr

use of soot.jimple.NewMultiArrayExpr in project soot by Sable.

the class UseChecker method caseAssignStmt.

public void caseAssignStmt(AssignStmt stmt) {
    Value lhs = stmt.getLeftOp();
    Value rhs = stmt.getRightOp();
    Type tlhs = null;
    if (lhs instanceof Local)
        tlhs = this.tg.get((Local) lhs);
    else if (lhs instanceof ArrayRef) {
        ArrayRef aref = (ArrayRef) lhs;
        Local base = (Local) aref.getBase();
        // Try to force Type integrity. The left side must agree on the
        // element type of the right side array reference.
        ArrayType at = null;
        Type tgType = this.tg.get(base);
        if (tgType instanceof ArrayType)
            at = (ArrayType) tgType;
        else {
            // is java.lang.Object
            if (tgType == Scene.v().getObjectType() && rhs instanceof Local) {
                Type rhsType = this.tg.get((Local) rhs);
                if (rhsType instanceof PrimType) {
                    if (defs == null) {
                        defs = LocalDefs.Factory.newLocalDefs(jb);
                        uses = LocalUses.Factory.newLocalUses(jb, defs);
                    }
                    // Check the original type of the array from the alloc site
                    for (Unit defU : defs.getDefsOfAt(base, stmt)) {
                        if (defU instanceof AssignStmt) {
                            AssignStmt defUas = (AssignStmt) defU;
                            if (defUas.getRightOp() instanceof NewArrayExpr) {
                                at = (ArrayType) defUas.getRightOp().getType();
                                break;
                            }
                        }
                    }
                }
            }
            if (at == null)
                at = tgType.makeArrayType();
        }
        tlhs = ((ArrayType) at).getElementType();
        this.handleArrayRef(aref, stmt);
        aref.setBase((Local) this.uv.visit(aref.getBase(), at, stmt));
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
        stmt.setLeftOp(this.uv.visit(lhs, tlhs, stmt));
    } else if (lhs instanceof FieldRef) {
        tlhs = ((FieldRef) lhs).getFieldRef().type();
        if (lhs instanceof InstanceFieldRef)
            this.handleInstanceFieldRef((InstanceFieldRef) lhs, stmt);
    }
    // They may have been changed above
    lhs = stmt.getLeftOp();
    rhs = stmt.getRightOp();
    if (rhs instanceof Local)
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    else if (rhs instanceof ArrayRef) {
        ArrayRef aref = (ArrayRef) rhs;
        Local base = (Local) aref.getBase();
        // try to force Type integrity
        ArrayType at = null;
        Type et = null;
        if (this.tg.get(base) instanceof ArrayType)
            at = (ArrayType) this.tg.get(base);
        else {
            Type bt = this.tg.get(base);
            // For some fixed type T, we assume that we can fix the array to T[].
            if (bt instanceof RefType || bt instanceof NullType) {
                RefType rt = bt instanceof NullType ? null : (RefType) bt;
                if (rt == null || rt.getSootClass().getName().equals("java.lang.Object") || rt.getSootClass().getName().equals("java.io.Serializable") || rt.getSootClass().getName().equals("java.lang.Cloneable")) {
                    if (defs == null) {
                        defs = LocalDefs.Factory.newLocalDefs(jb);
                        uses = LocalUses.Factory.newLocalUses(jb, defs);
                    }
                    outer: for (UnitValueBoxPair usePair : uses.getUsesOf(stmt)) {
                        Stmt useStmt = (Stmt) usePair.getUnit();
                        // from the callee's signature=
                        if (useStmt.containsInvokeExpr()) {
                            for (int i = 0; i < useStmt.getInvokeExpr().getArgCount(); i++) {
                                if (useStmt.getInvokeExpr().getArg(i) == usePair.getValueBox().getValue()) {
                                    et = useStmt.getInvokeExpr().getMethod().getParameterType(i);
                                    at = et.makeArrayType();
                                    break outer;
                                }
                            }
                        } else // if the other value is a primitive.
                        if (useStmt instanceof IfStmt) {
                            IfStmt ifStmt = (IfStmt) useStmt;
                            if (ifStmt.getCondition() instanceof EqExpr) {
                                EqExpr expr = (EqExpr) ifStmt.getCondition();
                                final Value other;
                                if (expr.getOp1() == usePair.getValueBox().getValue())
                                    other = expr.getOp2();
                                else
                                    other = expr.getOp1();
                                Type newEt = getTargetType(other);
                                if (newEt != null)
                                    et = newEt;
                            }
                        } else if (useStmt instanceof AssignStmt) {
                            // For binary expressions, we can look for type information in the
                            // other operands
                            AssignStmt useAssignStmt = (AssignStmt) useStmt;
                            if (useAssignStmt.getRightOp() instanceof BinopExpr) {
                                BinopExpr binOp = (BinopExpr) useAssignStmt.getRightOp();
                                final Value other;
                                if (binOp.getOp1() == usePair.getValueBox().getValue())
                                    other = binOp.getOp2();
                                else
                                    other = binOp.getOp1();
                                Type newEt = getTargetType(other);
                                if (newEt != null)
                                    et = newEt;
                            }
                        } else if (useStmt instanceof ReturnStmt) {
                            et = jb.getMethod().getReturnType();
                        }
                    }
                }
            }
            if (at == null)
                at = et.makeArrayType();
        }
        Type trhs = ((ArrayType) at).getElementType();
        this.handleArrayRef(aref, stmt);
        aref.setBase((Local) this.uv.visit(aref.getBase(), at, stmt));
        stmt.setRightOp(this.uv.visit(rhs, trhs, stmt));
    } else if (rhs instanceof InstanceFieldRef) {
        this.handleInstanceFieldRef((InstanceFieldRef) rhs, stmt);
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof BinopExpr)
        this.handleBinopExpr((BinopExpr) rhs, stmt, tlhs);
    else if (rhs instanceof InvokeExpr) {
        this.handleInvokeExpr((InvokeExpr) rhs, stmt);
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof CastExpr)
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    else if (rhs instanceof InstanceOfExpr) {
        InstanceOfExpr ioe = (InstanceOfExpr) rhs;
        ioe.setOp(this.uv.visit(ioe.getOp(), RefType.v("java.lang.Object"), stmt));
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof NewArrayExpr) {
        NewArrayExpr nae = (NewArrayExpr) rhs;
        nae.setSize(this.uv.visit(nae.getSize(), IntType.v(), stmt));
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof NewMultiArrayExpr) {
        NewMultiArrayExpr nmae = (NewMultiArrayExpr) rhs;
        for (int i = 0; i < nmae.getSizeCount(); i++) nmae.setSize(i, this.uv.visit(nmae.getSize(i), IntType.v(), stmt));
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof LengthExpr) {
        stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
    } else if (rhs instanceof NegExpr) {
        ((NegExpr) rhs).setOp(this.uv.visit(((NegExpr) rhs).getOp(), tlhs, stmt));
    } else if (rhs instanceof Constant)
        if (!(rhs instanceof NullConstant))
            stmt.setRightOp(this.uv.visit(rhs, tlhs, stmt));
}