Examples with ValueBox soot.ValueBox used on opensource projects

Example 36 with ValueBox

use of soot.ValueBox 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 37 with ValueBox

use of soot.ValueBox in project soot by Sable.

the class LocalNameStandardizer method internalTransform.

@Override
protected void internalTransform(Body body, String phaseName, Map<String, String> options) {
    boolean onlyStackName = PhaseOptions.getBoolean(options, "only-stack-locals");
    boolean sortLocals = PhaseOptions.getBoolean(options, "sort-locals");
    final BooleanType booleanType = BooleanType.v();
    final ByteType byteType = ByteType.v();
    final ShortType shortType = ShortType.v();
    final CharType charType = CharType.v();
    final IntType intType = IntType.v();
    final LongType longType = LongType.v();
    final DoubleType doubleType = DoubleType.v();
    final FloatType floatType = FloatType.v();
    final ErroneousType erroneousType = ErroneousType.v();
    final UnknownType unknownType = UnknownType.v();
    final StmtAddressType stmtAddressType = StmtAddressType.v();
    final NullType nullType = NullType.v();
    // Change the names to the standard forms now.
    {
        int objectCount = 0;
        int intCount = 0;
        int longCount = 0;
        int floatCount = 0;
        int doubleCount = 0;
        int addressCount = 0;
        int errorCount = 0;
        int nullCount = 0;
        /* The goal of this option is to ensure that local ordering remains
             * consistent between different iterations of soot. This helps to ensure
             * things like stable string representations of instructions and stable
             * jimple representations of a methods body when soot is used to load
             * the same code in different iterations.
             * 
             * First sorts the locals alphabetically by the string representation of
             * their type. Then if there are two locals with the same type, it uses
             * the only other source of structurally stable information (i.e. the 
             * instructions themselves) to produce an ordering for the locals
             * that remains consistent between different soot instances. It achieves
             * this by determining the position of a local's first occurrence in the 
             * instruction's list of definition statements. This position is then used
             * to sort the locals with the same type in an ascending order. 
             * 
             * The only times that this may not produce a consistent ordering for the 
             * locals between different soot instances is if a local is never defined in
             * the instructions or if the instructions themselves are changed in some way
             * that effects the ordering of the locals. In the first case, if a local is 
             * never defined, the other jimple body phases will remove this local as it is 
             * unused. As such, all we have to do is rerun this LocalNameStandardizer after
             * all other jimple body phases to eliminate any ambiguity introduced by these
             * phases and by the removed unused locals. In the second case, if the instructions
             * themselves changed then the user would have had to intentionally told soot to
             * modify the instructions of the code. Otherwise, the instructions would not have
             * changed because we assume the instructions to always be structurally stable
             * between different instances of soot. As such, in this instance, the user should
             * not be expecting soot to produce the same output as the input and thus the
             * ordering of the locals does not matter.
             */
        if (sortLocals) {
            Chain<Local> locals = body.getLocals();
            final List<ValueBox> defs = body.getDefBoxes();
            ArrayList<Local> sortedLocals = new ArrayList<Local>(locals);
            Collections.sort(sortedLocals, new Comparator<Local>() {

                private Map<Local, Integer> firstOccuranceCache = new HashMap<Local, Integer>();

                @Override
                public int compare(Local arg0, Local arg1) {
                    int ret = arg0.getType().toString().compareTo(arg1.getType().toString());
                    if (ret == 0) {
                        ret = Integer.compare(getFirstOccurance(arg0), getFirstOccurance(arg1));
                    }
                    return ret;
                }

                private int getFirstOccurance(Local l) {
                    Integer cur = firstOccuranceCache.get(l);
                    if (cur != null) {
                        return cur;
                    } else {
                        int count = 0;
                        int first = -1;
                        for (ValueBox vb : defs) {
                            Value v = vb.getValue();
                            if (v instanceof Local && v.equals(l)) {
                                first = count;
                                break;
                            }
                            count++;
                        }
                        firstOccuranceCache.put(l, first);
                        return first;
                    }
                }
            });
            locals.clear();
            locals.addAll(sortedLocals);
        }
        for (Local l : body.getLocals()) {
            String prefix = "";
            if (l.getName().startsWith("$"))
                prefix = "$";
            else {
                if (onlyStackName)
                    continue;
            }
            final Type type = l.getType();
            if (type.equals(booleanType))
                l.setName(prefix + "z" + intCount++);
            else if (type.equals(byteType))
                l.setName(prefix + "b" + longCount++);
            else if (type.equals(shortType))
                l.setName(prefix + "s" + longCount++);
            else if (type.equals(charType))
                l.setName(prefix + "c" + longCount++);
            else if (type.equals(intType))
                l.setName(prefix + "i" + longCount++);
            else if (type.equals(longType))
                l.setName(prefix + "l" + longCount++);
            else if (type.equals(doubleType))
                l.setName(prefix + "d" + doubleCount++);
            else if (type.equals(floatType))
                l.setName(prefix + "f" + floatCount++);
            else if (type.equals(stmtAddressType))
                l.setName(prefix + "a" + addressCount++);
            else if (type.equals(erroneousType) || type.equals(unknownType)) {
                l.setName(prefix + "e" + errorCount++);
            } else if (type.equals(nullType))
                l.setName(prefix + "n" + nullCount++);
            else
                l.setName(prefix + "r" + objectCount++);
        }
    }
}

Example 38 with ValueBox

use of soot.ValueBox in project soot by Sable.

the class UnusedLocalEliminator method internalTransform.

@Override
protected void internalTransform(Body body, String phaseName, Map<String, String> options) {
    if (Options.v().verbose())
        logger.debug("[" + body.getMethod().getName() + "] Eliminating unused locals...");
    int i = 0;
    int n = body.getLocals().size();
    int[] oldNumbers = new int[n];
    Chain<Local> locals = body.getLocals();
    for (Local local : locals) {
        oldNumbers[i] = local.getNumber();
        local.setNumber(i);
        i++;
    }
    boolean[] usedLocals = new boolean[n];
    // Traverse statements noting all the uses and defs
    for (Unit s : body.getUnits()) {
        for (ValueBox vb : s.getUseBoxes()) {
            Value v = vb.getValue();
            if (v instanceof Local) {
                Local l = (Local) v;
                assert locals.contains(l);
                usedLocals[l.getNumber()] = true;
            }
        }
        for (ValueBox vb : s.getDefBoxes()) {
            Value v = vb.getValue();
            if (v instanceof Local) {
                Local l = (Local) v;
                assert locals.contains(l);
                usedLocals[l.getNumber()] = true;
            }
        }
    }
    // Remove all locals that are unused.
    List<Local> keep = new ArrayList<Local>(body.getLocalCount());
    for (Local local : locals) {
        int lno = local.getNumber();
        local.setNumber(oldNumbers[lno]);
        if (usedLocals[lno]) {
            keep.add(local);
        }
    }
    body.getLocals().clear();
    body.getLocals().addAll(keep);
}

Example 39 with ValueBox

use of soot.ValueBox in project soot by Sable.

the class CombinedDUAnalysis method flowThrough.

// STEP 5: Define flow equations.
// in(s) = ( out(s) minus boxes(def(s)) ) union useboxes(s)
protected void flowThrough(FlowSet<ValueBox> out, Unit u, FlowSet<ValueBox> in) {
    Local def = localDefed(u);
    out.copy(in);
    if (def != null) {
        Collection<ValueBox> boxesDefed = localToUseBoxes.get(def);
        for (ValueBox vb : in) {
            if (boxesDefed.contains(vb))
                in.remove(vb);
        }
    }
    in.union(unitToLocalUseBoxes.get(u));
}

Example 40 with ValueBox

use of soot.ValueBox in project soot by Sable.

the class CombinedDUAnalysis method getLiveLocalsBefore.

public List<Local> getLiveLocalsBefore(Unit u) {
    List<Local> ret = liveLocalsBefore.get(u);
    if (ret == null) {
        HashSet<Local> hs = new HashSet<Local>();
        for (ValueBox vb : getFlowBefore(u)) {
            hs.add((Local) vb.getValue());
        }
        liveLocalsBefore.put(u, ret = new ArrayList<Local>(hs));
    }
    return ret;
}