Examples with Options soot.options.Options used on opensource projects

Example 1 with Options

use of soot.options.Options 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 Options

use of soot.options.Options in project soot by Sable.

the class DexlibAbstractInstruction method addTags.

/**
 * Tag the passed host with: - this instructions line number (if one is set)
 * - the original bytecode offset
 *
 * @param host
 *            the host to tag
 */
protected void addTags(Host host) {
    Options options = Options.v();
    if (options.keep_line_number() && lineNumber != -1) {
        host.addTag(new LineNumberTag(lineNumber));
        host.addTag(new SourceLineNumberTag(lineNumber));
    }
    if (options.keep_offset())
        host.addTag(new BytecodeOffsetTag(codeAddress));
}

Example 3 with Options

use of soot.options.Options in project soot by Sable.

the class DexBody method jimplify.

/**
 * Return the jimple equivalent of this body.
 *
 * @param m
 *            the SootMethod that contains this body
 */
public Body jimplify(Body b, SootMethod m) {
    final Jimple jimple = Jimple.v();
    final UnknownType unknownType = UnknownType.v();
    final NullConstant nullConstant = NullConstant.v();
    final Options options = Options.v();
    /*
		 * Timer t_whole_jimplification = new Timer(); Timer t_num = new
		 * Timer(); Timer t_null = new Timer();
		 * 
		 * t_whole_jimplification.start();
		 */
    jBody = (JimpleBody) b;
    deferredInstructions = new ArrayList<DeferableInstruction>();
    instructionsToRetype = new HashSet<RetypeableInstruction>();
    if (IDalvikTyper.ENABLE_DVKTYPER) {
        DalvikTyper.v().clear();
    }
    // process method parameters and generate Jimple locals from Dalvik
    // registers
    List<Local> paramLocals = new LinkedList<Local>();
    if (!isStatic) {
        int thisRegister = numRegisters - numParameterRegisters - 1;
        // generateLocal(UnknownType.v());
        Local thisLocal = jimple.newLocal("$u" + thisRegister, unknownType);
        jBody.getLocals().add(thisLocal);
        registerLocals[thisRegister] = thisLocal;
        JIdentityStmt idStmt = (JIdentityStmt) jimple.newIdentityStmt(thisLocal, jimple.newThisRef(declaringClassType));
        add(idStmt);
        paramLocals.add(thisLocal);
        if (IDalvikTyper.ENABLE_DVKTYPER) {
            DalvikTyper.v().setType(idStmt.leftBox, jBody.getMethod().getDeclaringClass().getType(), false);
        }
    }
    {
        // index of parameter type
        int i = 0;
        // index
        int parameterRegister = numRegisters - numParameterRegisters;
        // register
        for (Type t : parameterTypes) {
            // may
            Local gen = jimple.newLocal("$u" + parameterRegister, unknownType);
            // only
            // use
            // UnknownType
            // here
            // because
            // the
            // local
            // may
            // be
            // reused
            // with
            // a
            // different
            // type
            // later
            // (before
            // splitting)
            jBody.getLocals().add(gen);
            registerLocals[parameterRegister] = gen;
            JIdentityStmt idStmt = (JIdentityStmt) jimple.newIdentityStmt(gen, jimple.newParameterRef(t, i++));
            add(idStmt);
            paramLocals.add(gen);
            if (IDalvikTyper.ENABLE_DVKTYPER) {
                DalvikTyper.v().setType(idStmt.leftBox, t, false);
            }
            // used later in the Dalvik bytecode
            if (t instanceof LongType || t instanceof DoubleType) {
                parameterRegister++;
                // may
                Local g = jimple.newLocal("$u" + parameterRegister, unknownType);
                // only
                // use
                // UnknownType
                // here
                // because
                // the
                // local
                // may
                // be
                // reused
                // with
                // a
                // different
                // type
                // later
                // (before
                // splitting)
                jBody.getLocals().add(g);
                registerLocals[parameterRegister] = g;
            }
            parameterRegister++;
        }
    }
    for (int i = 0; i < (numRegisters - numParameterRegisters - (isStatic ? 0 : 1)); i++) {
        registerLocals[i] = jimple.newLocal("$u" + i, unknownType);
        jBody.getLocals().add(registerLocals[i]);
    }
    // add local to store intermediate results
    storeResultLocal = jimple.newLocal("$u-1", unknownType);
    jBody.getLocals().add(storeResultLocal);
    // process bytecode instructions
    final boolean isOdex = dexFile instanceof DexBackedDexFile ? ((DexBackedDexFile) dexFile).isOdexFile() : false;
    ClassPath cp = null;
    if (isOdex) {
        String[] sootClasspath = options.soot_classpath().split(File.pathSeparator);
        List<String> classpathList = new ArrayList<String>();
        for (String str : sootClasspath) classpathList.add(str);
        try {
            ClassPathResolver resolver = new ClassPathResolver(classpathList, classpathList, classpathList, dexFile);
            cp = new ClassPath(resolver.getResolvedClassProviders().toArray(new ClassProvider[0]));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    int prevLineNumber = -1;
    for (DexlibAbstractInstruction instruction : instructions) {
        if (isOdex && instruction instanceof OdexInstruction)
            ((OdexInstruction) instruction).deOdex(dexFile, method, cp);
        if (dangling != null) {
            dangling.finalize(this, instruction);
            dangling = null;
        }
        instruction.jimplify(this);
        if (instruction.getLineNumber() > 0)
            prevLineNumber = instruction.getLineNumber();
        else {
            instruction.setLineNumber(prevLineNumber);
        }
    }
    for (DeferableInstruction instruction : deferredInstructions) {
        instruction.deferredJimplify(this);
    }
    if (tries != null)
        addTraps();
    int prevLn = -1;
    final boolean keepLineNumber = options.keep_line_number();
    for (DexlibAbstractInstruction instruction : instructions) {
        Unit unit = instruction.getUnit();
        int lineNumber = unit.getJavaSourceStartLineNumber();
        if (keepLineNumber && lineNumber < 0) {
            if (prevLn >= 0) {
                unit.addTag(new LineNumberTag(prevLn));
                unit.addTag(new SourceLineNumberTag(prevLn));
            }
        } else {
            prevLn = lineNumber;
        }
    }
    // At this point Jimple code is generated
    // Cleaning...
    instructions = null;
    // registerLocals = null;
    // storeResultLocal = null;
    instructionAtAddress.clear();
    // localGenerator = null;
    deferredInstructions = null;
    // instructionsToRetype = null;
    dangling = null;
    tries = null;
    /*
		 * We eliminate dead code. Dead code has been shown to occur under the
		 * following circumstances.
		 *
		 * 0006ec: 0d00 |00a2: move-exception v0 ... 0006f2: 0d00 |00a5:
		 * move-exception v0 ... 0x0041 - 0x008a Ljava/lang/Throwable; -> 0x00a5
		 * <any> -> 0x00a2
		 * 
		 * Here there are two traps both over the same region. But the same
		 * always fires, hence rendering the code at a2 unreachable. Dead code
		 * yields problems during local splitting because locals within dead
		 * code will not be split. Hence we remove all dead code here.
		 */
    // Fix traps that do not catch exceptions
    DexTrapStackFixer.v().transform(jBody);
    // Sort out jump chains
    DexJumpChainShortener.v().transform(jBody);
    // Make sure that we don't have any overlapping uses due to returns
    DexReturnInliner.v().transform(jBody);
    // Shortcut: Reduce array initializations
    DexArrayInitReducer.v().transform(jBody);
    // split first to find undefined uses
    getLocalSplitter().transform(jBody);
    // Remove dead code and the corresponding locals before assigning types
    getUnreachableCodeEliminator().transform(jBody);
    DeadAssignmentEliminator.v().transform(jBody);
    UnusedLocalEliminator.v().transform(jBody);
    for (RetypeableInstruction i : instructionsToRetype) i.retype(jBody);
    if (IDalvikTyper.ENABLE_DVKTYPER) {
        DexReturnValuePropagator.v().transform(jBody);
        getCopyPopagator().transform(jBody);
        DexNullThrowTransformer.v().transform(jBody);
        DalvikTyper.v().typeUntypedConstrantInDiv(jBody);
        DeadAssignmentEliminator.v().transform(jBody);
        UnusedLocalEliminator.v().transform(jBody);
        DalvikTyper.v().assignType(jBody);
        // jBody.validate();
        jBody.validateUses();
        jBody.validateValueBoxes();
    // jBody.checkInit();
    // Validate.validateArrays(jBody);
    // jBody.checkTypes();
    // jBody.checkLocals();
    } else {
        // t_num.start();
        DexNumTransformer.v().transform(jBody);
        // t_num.end();
        DexReturnValuePropagator.v().transform(jBody);
        getCopyPopagator().transform(jBody);
        DexNullThrowTransformer.v().transform(jBody);
        // t_null.start();
        DexNullTransformer.v().transform(jBody);
        // t_null.end();
        DexIfTransformer.v().transform(jBody);
        DeadAssignmentEliminator.v().transform(jBody);
        UnusedLocalEliminator.v().transform(jBody);
        // DexRefsChecker.v().transform(jBody);
        DexNullArrayRefTransformer.v().transform(jBody);
    }
    if (IDalvikTyper.ENABLE_DVKTYPER) {
        for (Local l : jBody.getLocals()) {
            l.setType(unknownType);
        }
    }
    // Remove "instanceof" checks on the null constant
    DexNullInstanceofTransformer.v().transform(jBody);
    TypeAssigner.v().transform(jBody);
    final RefType objectType = RefType.v("java.lang.Object");
    if (IDalvikTyper.ENABLE_DVKTYPER) {
        for (Unit u : jBody.getUnits()) {
            if (u instanceof IfStmt) {
                ConditionExpr expr = (ConditionExpr) ((IfStmt) u).getCondition();
                if (((expr instanceof EqExpr) || (expr instanceof NeExpr))) {
                    Value op1 = expr.getOp1();
                    Value op2 = expr.getOp2();
                    if (op1 instanceof Constant && op2 instanceof Local) {
                        Local l = (Local) op2;
                        Type ltype = l.getType();
                        if (ltype instanceof PrimType)
                            continue;
                        if (// by default
                        !(op1 instanceof IntConstant))
                            // in Dalvik
                            continue;
                        IntConstant icst = (IntConstant) op1;
                        int val = icst.value;
                        if (val != 0)
                            continue;
                        expr.setOp1(nullConstant);
                    } else if (op1 instanceof Local && op2 instanceof Constant) {
                        Local l = (Local) op1;
                        Type ltype = l.getType();
                        if (ltype instanceof PrimType)
                            continue;
                        if (// by default
                        !(op2 instanceof IntConstant))
                            // in Dalvik
                            continue;
                        IntConstant icst = (IntConstant) op2;
                        int val = icst.value;
                        if (val != 0)
                            continue;
                        expr.setOp2(nullConstant);
                    } else if (op1 instanceof Local && op2 instanceof Local) {
                    // nothing to do
                    } else if (op1 instanceof Constant && op2 instanceof Constant) {
                        if (op1 instanceof NullConstant && op2 instanceof NumericConstant) {
                            IntConstant nc = (IntConstant) op2;
                            if (nc.value != 0)
                                throw new RuntimeException("expected value 0 for int constant. Got " + expr);
                            expr.setOp2(NullConstant.v());
                        } else if (op2 instanceof NullConstant && op1 instanceof NumericConstant) {
                            IntConstant nc = (IntConstant) op1;
                            if (nc.value != 0)
                                throw new RuntimeException("expected value 0 for int constant. Got " + expr);
                            expr.setOp1(nullConstant);
                        }
                    } else {
                        throw new RuntimeException("error: do not handle if: " + u);
                    }
                }
            }
        }
        // For null_type locals: replace their use by NullConstant()
        List<ValueBox> uses = jBody.getUseBoxes();
        // List<ValueBox> defs = jBody.getDefBoxes();
        List<ValueBox> toNullConstantify = new ArrayList<ValueBox>();
        List<Local> toRemove = new ArrayList<Local>();
        for (Local l : jBody.getLocals()) {
            if (l.getType() instanceof NullType) {
                toRemove.add(l);
                for (ValueBox vb : uses) {
                    Value v = vb.getValue();
                    if (v == l)
                        toNullConstantify.add(vb);
                }
            }
        }
        for (ValueBox vb : toNullConstantify) {
            System.out.println("replace valuebox '" + vb + " with null constant");
            vb.setValue(nullConstant);
        }
        for (Local l : toRemove) {
            System.out.println("removing null_type local " + l);
            l.setType(objectType);
        }
    }
    // We pack locals that are not used in overlapping regions. This may
    // again lead to unused locals which we have to remove.
    LocalPacker.v().transform(jBody);
    UnusedLocalEliminator.v().transform(jBody);
    LocalNameStandardizer.v().transform(jBody);
    // on the fly.
    if (options.wrong_staticness() == Options.wrong_staticness_fix) {
        FieldStaticnessCorrector.v().transform(jBody);
        MethodStaticnessCorrector.v().transform(jBody);
    }
    // Inline PackManager.v().getPack("jb").apply(jBody);
    // Keep only transformations that have not been done
    // at this point.
    TrapTightener.v().transform(jBody);
    TrapMinimizer.v().transform(jBody);
    // LocalSplitter.v().transform(jBody);
    Aggregator.v().transform(jBody);
    // UnusedLocalEliminator.v().transform(jBody);
    // TypeAssigner.v().transform(jBody);
    // LocalPacker.v().transform(jBody);
    // LocalNameStandardizer.v().transform(jBody);
    // Remove if (null == null) goto x else <madness>. We can only do this
    // after we have run the constant propagation as we might not be able
    // to statically decide the conditions earlier.
    ConditionalBranchFolder.v().transform(jBody);
    // Remove unnecessary typecasts
    ConstantCastEliminator.v().transform(jBody);
    IdentityCastEliminator.v().transform(jBody);
    // Remove unnecessary logic operations
    IdentityOperationEliminator.v().transform(jBody);
    // We need to run this transformer since the conditional branch folder
    // might have rendered some code unreachable (well, it was unreachable
    // before as well, but we didn't know).
    UnreachableCodeEliminator.v().transform(jBody);
    // Not sure whether we need this even though we do it earlier on as
    // the earlier pass does not have type information
    // CopyPropagator.v().transform(jBody);
    // we might have gotten new dead assignments and unused locals through
    // copy propagation and unreachable code elimination, so we have to do
    // this again
    DeadAssignmentEliminator.v().transform(jBody);
    UnusedLocalEliminator.v().transform(jBody);
    NopEliminator.v().transform(jBody);
    // Remove unnecessary chains of return statements
    DexReturnPacker.v().transform(jBody);
    for (Unit u : jBody.getUnits()) {
        if (u instanceof AssignStmt) {
            AssignStmt ass = (AssignStmt) u;
            if (ass.getRightOp() instanceof CastExpr) {
                CastExpr c = (CastExpr) ass.getRightOp();
                if (c.getType() instanceof NullType) {
                    ass.setRightOp(nullConstant);
                }
            }
        }
        if (u instanceof DefinitionStmt) {
            DefinitionStmt def = (DefinitionStmt) u;
            // we must manually fix the hierarchy
            if (def.getLeftOp() instanceof Local && def.getRightOp() instanceof CaughtExceptionRef) {
                Type t = def.getLeftOp().getType();
                if (t instanceof RefType) {
                    RefType rt = (RefType) t;
                    if (rt.getSootClass().isPhantom() && !rt.getSootClass().hasSuperclass() && !rt.getSootClass().getName().equals("java.lang.Throwable"))
                        rt.getSootClass().setSuperclass(Scene.v().getSootClass("java.lang.Throwable"));
                }
            }
        }
    }
    // 
    for (Local l : jBody.getLocals()) {
        Type t = l.getType();
        if (t instanceof NullType) {
            l.setType(objectType);
        }
    }
    return jBody;
}