Examples with LocalDefs soot.toolkits.scalar.LocalDefs used on opensource projects

Example 1 with LocalDefs

use of soot.toolkits.scalar.LocalDefs 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 LocalDefs

use of soot.toolkits.scalar.LocalDefs in project soot by Sable.

the class Validate method validateArrays.

public static void validateArrays(Body b) {
    Set<DefinitionStmt> definitions = new HashSet<DefinitionStmt>();
    Set<Unit> unitWithArrayRef = new HashSet<Unit>();
    for (Unit u : b.getUnits()) {
        if (u instanceof DefinitionStmt) {
            DefinitionStmt s = (DefinitionStmt) u;
            definitions.add(s);
        }
        List<ValueBox> uses = u.getUseBoxes();
        for (ValueBox vb : uses) {
            Value v = vb.getValue();
            if (v instanceof ArrayRef) {
                unitWithArrayRef.add(u);
            }
        }
    }
    final LocalDefs localDefs = LocalDefs.Factory.newLocalDefs(b, true);
    Set<Unit> toReplace = new HashSet<Unit>();
    for (Unit u : unitWithArrayRef) {
        boolean ok = false;
        List<ValueBox> uses = u.getUseBoxes();
        for (ValueBox vb : uses) {
            Value v = vb.getValue();
            if (v instanceof ArrayRef) {
                ArrayRef ar = (ArrayRef) v;
                Local base = (Local) ar.getBase();
                List<Unit> defs = localDefs.getDefsOfAt(base, u);
                // add aliases
                Set<Unit> alreadyHandled = new HashSet<Unit>();
                while (true) {
                    boolean isMore = false;
                    for (Unit d : defs) {
                        if (alreadyHandled.contains(d))
                            continue;
                        if (d instanceof AssignStmt) {
                            AssignStmt ass = (AssignStmt) d;
                            Value r = ass.getRightOp();
                            if (r instanceof Local) {
                                defs.addAll(localDefs.getDefsOfAt((Local) r, d));
                                alreadyHandled.add(d);
                                isMore = true;
                                break;
                            } else if (r instanceof ArrayRef) {
                                ArrayRef arrayRef = (ArrayRef) r;
                                Local l = (Local) arrayRef.getBase();
                                defs.addAll(localDefs.getDefsOfAt(l, d));
                                alreadyHandled.add(d);
                                isMore = true;
                                break;
                            }
                        }
                    }
                    if (!isMore)
                        break;
                }
                // System.out.println("def size "+ defs.size());
                for (Unit def : defs) {
                    // System.out.println("def u "+ def);
                    Value r = null;
                    if (def instanceof IdentityStmt) {
                        IdentityStmt idstmt = (IdentityStmt) def;
                        r = idstmt.getRightOp();
                    } else if (def instanceof AssignStmt) {
                        AssignStmt assStmt = (AssignStmt) def;
                        r = assStmt.getRightOp();
                    } else {
                        throw new RuntimeException("error: definition statement not an IdentityStmt nor an AssignStmt! " + def);
                    }
                    Type t = null;
                    if (r instanceof InvokeExpr) {
                        InvokeExpr ie = (InvokeExpr) r;
                        t = ie.getType();
                        // System.out.println("ie type: "+ t +" "+ t.getClass());
                        if (t instanceof ArrayType)
                            ok = true;
                    } else if (r instanceof FieldRef) {
                        FieldRef ref = (FieldRef) r;
                        t = ref.getType();
                        // System.out.println("fr type: "+ t +" "+ t.getClass());
                        if (t instanceof ArrayType)
                            ok = true;
                    } else if (r instanceof IdentityRef) {
                        IdentityRef ir = (IdentityRef) r;
                        t = ir.getType();
                        if (t instanceof ArrayType)
                            ok = true;
                    } else if (r instanceof CastExpr) {
                        CastExpr c = (CastExpr) r;
                        t = c.getType();
                        if (t instanceof ArrayType)
                            ok = true;
                    } else if (r instanceof ArrayRef) {
                    // we also check that this arrayref is correctly defined
                    } else if (r instanceof NewArrayExpr) {
                        ok = true;
                    } else if (r instanceof Local) {
                    } else if (r instanceof Constant) {
                    } else {
                        throw new RuntimeException("error: unknown right hand side of definition stmt " + def);
                    }
                    if (ok)
                        break;
                }
                if (ok)
                    break;
            }
        }
        if (!ok) {
            toReplace.add(u);
        }
    }
    int i = 0;
    for (Unit u : toReplace) {
        System.out.println("warning: incorrect array def, replacing unit " + u);
        // new object
        RefType throwableType = RefType.v("java.lang.Throwable");
        Local ttt = Jimple.v().newLocal("ttt_" + ++i, throwableType);
        b.getLocals().add(ttt);
        Value r = Jimple.v().newNewExpr(throwableType);
        Unit initLocalUnit = Jimple.v().newAssignStmt(ttt, r);
        // call <init> method with a string parameter for message
        List<String> pTypes = new ArrayList<String>();
        pTypes.add("java.lang.String");
        boolean isStatic = false;
        SootMethodRef mRef = Validate.makeMethodRef("java.lang.Throwable", "<init>", "", pTypes, isStatic);
        List<Value> parameters = new ArrayList<Value>();
        parameters.add(StringConstant.v("Soot updated this instruction"));
        InvokeExpr ie = Jimple.v().newSpecialInvokeExpr(ttt, mRef, parameters);
        Unit initMethod = Jimple.v().newInvokeStmt(ie);
        // throw exception
        Unit newUnit = Jimple.v().newThrowStmt(ttt);
        // change instruction in body
        b.getUnits().swapWith(u, newUnit);
        b.getUnits().insertBefore(initMethod, newUnit);
        b.getUnits().insertBefore(initLocalUnit, initMethod);
    // Exception a = throw new Exception();
    }
    DeadAssignmentEliminator.v().transform(b);
    UnusedLocalEliminator.v().transform(b);
    NopEliminator.v().transform(b);
    UnreachableCodeEliminator.v().transform(b);
}

Example 3 with LocalDefs

use of soot.toolkits.scalar.LocalDefs in project soot by Sable.

the class TypeResolver method split_new.

/* Taken from the soot.jimple.toolkits.typing.TypeResolver class of Soot
	version 2.2.5. */
private void split_new() {
    LocalDefs defs = LocalDefs.Factory.newLocalDefs(jb);
    PatchingChain<Unit> units = this.jb.getUnits();
    Stmt[] stmts = new Stmt[units.size()];
    units.toArray(stmts);
    final Jimple jimple = Jimple.v();
    for (Stmt stmt : stmts) {
        if (stmt instanceof InvokeStmt) {
            InvokeStmt invoke = (InvokeStmt) stmt;
            if (invoke.getInvokeExpr() instanceof SpecialInvokeExpr) {
                SpecialInvokeExpr special = (SpecialInvokeExpr) invoke.getInvokeExpr();
                if (special.getMethodRef().name().equals("<init>")) {
                    List<Unit> deflist = defs.getDefsOfAt((Local) special.getBase(), invoke);
                    while (deflist.size() == 1) {
                        Stmt stmt2 = (Stmt) deflist.get(0);
                        if (stmt2 instanceof AssignStmt) {
                            AssignStmt assign = (AssignStmt) stmt2;
                            if (assign.getRightOp() instanceof Local) {
                                deflist = defs.getDefsOfAt((Local) assign.getRightOp(), assign);
                                continue;
                            } else if (assign.getRightOp() instanceof NewExpr) {
                                Local newlocal = jimple.newLocal("tmp", null);
                                newlocal.setName("tmp$" + System.identityHashCode(newlocal));
                                this.jb.getLocals().add(newlocal);
                                special.setBase(newlocal);
                                DefinitionStmt assignStmt = jimple.newAssignStmt(assign.getLeftOp(), newlocal);
                                Unit u = Util.findLastIdentityUnit(jb, assign);
                                units.insertAfter(assignStmt, u);
                                assign.setLeftOp(newlocal);
                                this.addLocal(newlocal);
                                this.initAssignment(assignStmt);
                            }
                        }
                        break;
                    }
                }
            }
        }
    }
}

Example 4 with LocalDefs

use of soot.toolkits.scalar.LocalDefs in project soot by Sable.

the class Aggregator method internalAggregate.

private static boolean internalAggregate(StmtBody body, Map<ValueBox, Zone> boxToZone, boolean onlyStackVars) {
    boolean hadAggregation = false;
    Chain<Unit> units = body.getUnits();
    ExceptionalUnitGraph graph = new ExceptionalUnitGraph(body);
    LocalDefs localDefs = LocalDefs.Factory.newLocalDefs(graph);
    LocalUses localUses = LocalUses.Factory.newLocalUses(body, localDefs);
    List<Unit> unitList = new PseudoTopologicalOrderer<Unit>().newList(graph, false);
    for (Unit u : unitList) {
        if (!(u instanceof AssignStmt))
            continue;
        AssignStmt s = (AssignStmt) u;
        Value lhs = s.getLeftOp();
        if (!(lhs instanceof Local))
            continue;
        Local lhsLocal = (Local) lhs;
        if (onlyStackVars && !lhsLocal.getName().startsWith("$"))
            continue;
        List<UnitValueBoxPair> lu = localUses.getUsesOf(s);
        if (lu.size() != 1)
            continue;
        UnitValueBoxPair usepair = lu.get(0);
        Unit use = usepair.unit;
        ValueBox useBox = usepair.valueBox;
        List<Unit> ld = localDefs.getDefsOfAt(lhsLocal, use);
        if (ld.size() != 1)
            continue;
        // Check to make sure aggregation pair in the same zone
        if (boxToZone.get(s.getRightOpBox()) != boxToZone.get(usepair.valueBox)) {
            continue;
        }
        /* we need to check the path between def and use */
        /* to see if there are any intervening re-defs of RHS */
        /* in fact, we should check that this path is unique. */
        /*
			 * if the RHS uses only locals, then we know what to do; if RHS has
			 * a method invocation f(a, b, c) or field access, we must ban field
			 * writes, other method calls and (as usual) writes to a, b, c.
			 */
        boolean cantAggr = false;
        boolean propagatingInvokeExpr = false;
        boolean propagatingFieldRef = false;
        boolean propagatingArrayRef = false;
        List<FieldRef> fieldRefList = new ArrayList<FieldRef>();
        List<Value> localsUsed = new ArrayList<Value>();
        for (ValueBox vb : s.getUseBoxes()) {
            Value v = vb.getValue();
            if (v instanceof Local) {
                localsUsed.add(v);
            } else if (v instanceof InvokeExpr) {
                propagatingInvokeExpr = true;
            } else if (v instanceof ArrayRef) {
                propagatingArrayRef = true;
            } else if (v instanceof FieldRef) {
                propagatingFieldRef = true;
                fieldRefList.add((FieldRef) v);
            }
        }
        // look for a path from s to use in graph.
        // only look in an extended basic block, though.
        List<Unit> path = graph.getExtendedBasicBlockPathBetween(s, use);
        if (path == null)
            continue;
        Iterator<Unit> pathIt = path.iterator();
        // skip s.
        if (pathIt.hasNext())
            pathIt.next();
        while (pathIt.hasNext() && !cantAggr) {
            Stmt between = (Stmt) (pathIt.next());
            if (between != use) {
                for (ValueBox vb : between.getDefBoxes()) {
                    Value v = vb.getValue();
                    if (localsUsed.contains(v)) {
                        cantAggr = true;
                        break;
                    }
                    if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) {
                        if (v instanceof FieldRef) {
                            if (propagatingInvokeExpr) {
                                cantAggr = true;
                                break;
                            } else if (propagatingFieldRef) {
                                // aliased
                                for (FieldRef fieldRef : fieldRefList) {
                                    if (isSameField((FieldRef) v, fieldRef)) {
                                        cantAggr = true;
                                        break;
                                    }
                                }
                            }
                        } else if (v instanceof ArrayRef) {
                            if (propagatingInvokeExpr) {
                                // Cannot aggregate an invoke expr past an
                                // array write
                                cantAggr = true;
                                break;
                            } else if (propagatingArrayRef) {
                                // cannot aggregate an array read past a
                                // write
                                // this is somewhat conservative
                                // (if types differ they may not be aliased)
                                cantAggr = true;
                                break;
                            }
                        }
                    }
                }
                // Make sure not propagating past a {enter,exit}Monitor
                if (propagatingInvokeExpr && between instanceof MonitorStmt)
                    cantAggr = true;
            }
            // Check for intervening side effects due to method calls
            if (propagatingInvokeExpr || propagatingFieldRef || propagatingArrayRef) {
                for (final ValueBox box : between.getUseBoxes()) {
                    if (between == use && box == useBox) {
                        // side effects
                        break;
                    }
                    Value v = box.getValue();
                    if (v instanceof InvokeExpr || (propagatingInvokeExpr && (v instanceof FieldRef || v instanceof ArrayRef))) {
                        cantAggr = true;
                        break;
                    }
                }
            }
        }
        // we give up: can't aggregate.
        if (cantAggr) {
            continue;
        }
        /* assuming that the d-u chains are correct, */
        /* we need not check the actual contents of ld */
        Value aggregatee = s.getRightOp();
        if (usepair.valueBox.canContainValue(aggregatee)) {
            boolean wasSimpleCopy = isSimpleCopy(usepair.unit);
            usepair.valueBox.setValue(aggregatee);
            units.remove(s);
            hadAggregation = true;
            // followed by an invoke, the invoke gets the tags.
            if (wasSimpleCopy) {
                // usepair.unit.removeAllTags();
                usepair.unit.addAllTagsOf(s);
            }
        } else {
        /*
					 * if(Options.v().verbose()) {
					 * logger.debug("[debug] failed aggregation");
					 * logger.debug("[debug] tried to put "+aggregatee+
					 * " into "+usepair.stmt +
					 * ": in particular, "+usepair.valueBox);
					 * logger.debug("[debug] aggregatee instanceof Expr: "
					 * +(aggregatee instanceof Expr)); }
					 */
        }
    }
    return hadAggregation;
}

Example 5 with LocalDefs

use of soot.toolkits.scalar.LocalDefs in project soot by Sable.

the class CopyPropagator method internalTransform.

/**
 * Cascaded copy propagator.
 *
 * If it encounters situations of the form: A: a = ...; B: ... x = a; C:...
 * use (x); where a has only one definition, and x has only one definition
 * (B), then it can propagate immediately without checking between B and C
 * for redefinitions of a (namely) A because they cannot occur. In this case
 * the propagator is global.
 *
 * Otherwise, if a has multiple definitions then it only checks for
 * redefinitions of Propagates constants and copies in extended basic
 * blocks.
 *
 * Does not propagate stack locals when the "only-regular-locals" option is
 * true.
 */
protected void internalTransform(Body b, String phaseName, Map<String, String> opts) {
    CPOptions options = new CPOptions(opts);
    StmtBody stmtBody = (StmtBody) b;
    int fastCopyPropagationCount = 0;
    int slowCopyPropagationCount = 0;
    if (Options.v().verbose())
        logger.debug("[" + stmtBody.getMethod().getName() + "] Propagating copies...");
    if (Options.v().time())
        Timers.v().propagatorTimer.start();
    Chain<Unit> units = stmtBody.getUnits();
    Map<Local, Integer> localToDefCount = new HashMap<Local, Integer>();
    // Count number of definitions for each local.
    for (Unit u : units) {
        Stmt s = (Stmt) u;
        if (s instanceof DefinitionStmt && ((DefinitionStmt) s).getLeftOp() instanceof Local) {
            Local l = (Local) ((DefinitionStmt) s).getLeftOp();
            if (!localToDefCount.containsKey(l))
                localToDefCount.put(l, new Integer(1));
            else
                localToDefCount.put(l, new Integer(localToDefCount.get(l).intValue() + 1));
        }
    }
    if (throwAnalysis == null)
        throwAnalysis = Scene.v().getDefaultThrowAnalysis();
    if (forceOmitExceptingUnitEdges == false)
        forceOmitExceptingUnitEdges = Options.v().omit_excepting_unit_edges();
    // Go through the definitions, building the webs
    UnitGraph graph = new ExceptionalUnitGraph(stmtBody, throwAnalysis, forceOmitExceptingUnitEdges);
    LocalDefs localDefs = LocalDefs.Factory.newLocalDefs(graph);
    // Perform a local propagation pass.
    {
        Iterator<Unit> stmtIt = (new PseudoTopologicalOrderer<Unit>()).newList(graph, false).iterator();
        while (stmtIt.hasNext()) {
            Stmt stmt = (Stmt) stmtIt.next();
            for (ValueBox useBox : stmt.getUseBoxes()) {
                if (useBox.getValue() instanceof Local) {
                    Local l = (Local) useBox.getValue();
                    // null due to typing, we always inline that constant.
                    if (!(l.getType() instanceof NullType)) {
                        if (options.only_regular_locals() && l.getName().startsWith("$"))
                            continue;
                        if (options.only_stack_locals() && !l.getName().startsWith("$"))
                            continue;
                    }
                    List<Unit> defsOfUse = localDefs.getDefsOfAt(l, stmt);
                    // We can propagate the definition if we either only
                    // have
                    // one definition or all definitions are side-effect
                    // free
                    // and equal. For starters, we only support constants in
                    // the case of multiple definitions.
                    boolean propagateDef = defsOfUse.size() == 1;
                    if (!propagateDef && defsOfUse.size() > 0) {
                        boolean agrees = true;
                        Constant constVal = null;
                        for (Unit defUnit : defsOfUse) {
                            boolean defAgrees = false;
                            if (defUnit instanceof AssignStmt) {
                                AssignStmt assign = (AssignStmt) defUnit;
                                if (assign.getRightOp() instanceof Constant) {
                                    if (constVal == null) {
                                        constVal = (Constant) assign.getRightOp();
                                        defAgrees = true;
                                    } else if (constVal.equals(assign.getRightOp()))
                                        defAgrees = true;
                                }
                            }
                            agrees &= defAgrees;
                        }
                        propagateDef = agrees;
                    }
                    if (propagateDef) {
                        DefinitionStmt def = (DefinitionStmt) defsOfUse.get(0);
                        if (def.getRightOp() instanceof Constant) {
                            if (useBox.canContainValue(def.getRightOp())) {
                                useBox.setValue(def.getRightOp());
                            }
                        } else if (def.getRightOp() instanceof CastExpr) {
                            CastExpr ce = (CastExpr) def.getRightOp();
                            if (ce.getCastType() instanceof RefLikeType) {
                                boolean isConstNull = ce.getOp() instanceof IntConstant && ((IntConstant) ce.getOp()).value == 0;
                                isConstNull |= ce.getOp() instanceof LongConstant && ((LongConstant) ce.getOp()).value == 0;
                                if (isConstNull) {
                                    if (useBox.canContainValue(NullConstant.v())) {
                                        useBox.setValue(NullConstant.v());
                                    }
                                }
                            }
                        } else if (def.getRightOp() instanceof Local) {
                            Local m = (Local) def.getRightOp();
                            if (l != m) {
                                Integer defCount = localToDefCount.get(m);
                                if (defCount == null || defCount == 0)
                                    throw new RuntimeException("Variable " + m + " used without definition!");
                                if (defCount == 1) {
                                    useBox.setValue(m);
                                    fastCopyPropagationCount++;
                                    continue;
                                }
                                List<Unit> path = graph.getExtendedBasicBlockPathBetween(def, stmt);
                                if (path == null) {
                                    // no path in the extended basic block
                                    continue;
                                }
                                Iterator<Unit> pathIt = path.iterator();
                                // Skip first node
                                pathIt.next();
                                // Make sure that m is not redefined along
                                // path
                                {
                                    boolean isRedefined = false;
                                    while (pathIt.hasNext()) {
                                        Stmt s = (Stmt) pathIt.next();
                                        if (stmt == s) {
                                            break;
                                        }
                                        if (s instanceof DefinitionStmt) {
                                            if (((DefinitionStmt) s).getLeftOp() == m) {
                                                isRedefined = true;
                                                break;
                                            }
                                        }
                                    }
                                    if (isRedefined)
                                        continue;
                                }
                                useBox.setValue(m);
                                slowCopyPropagationCount++;
                            }
                        }
                    }
                }
            }
        }
    }
    if (Options.v().verbose())
        logger.debug("[" + stmtBody.getMethod().getName() + "]     Propagated: " + fastCopyPropagationCount + " fast copies  " + slowCopyPropagationCount + " slow copies");
    if (Options.v().time())
        Timers.v().propagatorTimer.end();
}