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

Example 6 with ExceptionalUnitGraph

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

the class PurityInterproceduralAnalysis method analyseMethod.

@Override
protected void analyseMethod(SootMethod method, PurityGraphBox dst) {
    Body body = method.retrieveActiveBody();
    ExceptionalUnitGraph graph = new ExceptionalUnitGraph(body);
    new PurityIntraproceduralAnalysis(graph, this).copyResult(dst);
}

Example 7 with ExceptionalUnitGraph

use of soot.toolkits.graph.ExceptionalUnitGraph 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 8 with ExceptionalUnitGraph

use of soot.toolkits.graph.ExceptionalUnitGraph 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();
}

Example 9 with ExceptionalUnitGraph

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

the class UnreachableCodeEliminator method internalTransform.

protected void internalTransform(Body body, String phaseName, Map<String, String> options) {
    if (Options.v().verbose()) {
        logger.debug("[" + body.getMethod().getName() + "] Eliminating unreachable code...");
    }
    // says that none of them can throw the caught exception.
    if (this.throwAnalysis == null)
        this.throwAnalysis = PhaseOptions.getBoolean(options, "remove-unreachable-traps", true) ? Scene.v().getDefaultThrowAnalysis() : PedanticThrowAnalysis.v();
    ExceptionalUnitGraph graph = new ExceptionalUnitGraph(body, throwAnalysis, false);
    Chain<Unit> units = body.getUnits();
    int numPruned = units.size();
    Set<Unit> reachable = units.isEmpty() ? Collections.<Unit>emptySet() : reachable(units.getFirst(), graph);
    // source.
    for (Iterator<Trap> it = body.getTraps().iterator(); it.hasNext(); ) {
        Trap trap = it.next();
        if ((trap.getBeginUnit() == trap.getEndUnit()) || !reachable.contains(trap.getHandlerUnit())) {
            it.remove();
        }
    }
    // alive are kept in the code
    for (Trap t : body.getTraps()) if (t.getEndUnit() == body.getUnits().getLast())
        reachable.add(t.getEndUnit());
    Set<Unit> notReachable = new HashSet<Unit>();
    if (Options.v().verbose()) {
        for (Unit u : units) {
            if (!reachable.contains(u))
                notReachable.add(u);
        }
    }
    units.retainAll(reachable);
    numPruned -= units.size();
    if (Options.v().verbose()) {
        logger.debug("[" + body.getMethod().getName() + "]	 Removed " + numPruned + " statements: ");
        for (Unit u : notReachable) {
            logger.debug("[" + body.getMethod().getName() + "]	         " + u);
        }
    }
}

Example 10 with ExceptionalUnitGraph

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

the class SynchronizedMethodTransformer method internalTransform.

protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
    if (!b.getMethod().isSynchronized() || b.getMethod().isStatic())
        return;
    Iterator<Unit> it = b.getUnits().snapshotIterator();
    while (it.hasNext()) {
        Unit u = it.next();
        if (u instanceof IdentityStmt)
            continue;
        // instruction, we generate one
        if (!(u instanceof EnterMonitorStmt)) {
            b.getUnits().insertBeforeNoRedirect(Jimple.v().newEnterMonitorStmt(b.getThisLocal()), u);
            // We also need to leave the monitor when the method terminates
            UnitGraph graph = new ExceptionalUnitGraph(b);
            for (Unit tail : graph.getTails()) b.getUnits().insertBefore(Jimple.v().newExitMonitorStmt(b.getThisLocal()), tail);
        }
        break;
    }
}