WALA/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/ForInContextSelector.java

386 lines
15 KiB
Java
Executable File

/*******************************************************************************
* Copyright (c) 2008 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.cast.js.ipa.callgraph;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import com.ibm.wala.cast.ir.ssa.AbstractReflectiveGet;
import com.ibm.wala.cast.ir.ssa.AstIRFactory;
import com.ibm.wala.cast.ir.ssa.AstIsDefinedInstruction;
import com.ibm.wala.cast.ir.ssa.EachElementGetInstruction;
import com.ibm.wala.cast.js.types.JavaScriptTypes;
import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.Context;
import com.ibm.wala.ipa.callgraph.ContextItem;
import com.ibm.wala.ipa.callgraph.ContextKey;
import com.ibm.wala.ipa.callgraph.ContextSelector;
import com.ibm.wala.ipa.callgraph.impl.Everywhere;
import com.ibm.wala.ipa.callgraph.propagation.ConcreteTypeKey;
import com.ibm.wala.ipa.callgraph.propagation.ConstantKey;
import com.ibm.wala.ipa.callgraph.propagation.FilteredPointerKey;
import com.ibm.wala.ipa.callgraph.propagation.FilteredPointerKey.SingleInstanceFilter;
import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
import com.ibm.wala.ipa.cha.IClassHierarchy;
import com.ibm.wala.ssa.DefUse;
import com.ibm.wala.ssa.IR;
import com.ibm.wala.ssa.IRFactory;
import com.ibm.wala.ssa.ReflectiveMemberAccess;
import com.ibm.wala.ssa.SSAAbstractInvokeInstruction;
import com.ibm.wala.ssa.SSAGetInstruction;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.ssa.SSAOptions;
import com.ibm.wala.types.MethodReference;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.Iterator2Iterable;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.IntSetUtil;
import com.ibm.wala.util.intset.MutableIntSet;
public class ForInContextSelector implements ContextSelector {
public final static ContextKey FORIN_KEY = new ContextKey() { };
public final static ContextKey FORIN_PARM_INDEX = new ContextKey() { };
public static final ContextItem FORIN_MARKER = new ContextItem() { };
public static final String HACK_METHOD_STR = "_forin_body";
// if this flag is set to true, functions are given ForInContexts based on their name
// if it is false, any function that uses its first argument as a property name will be given a ForInContext
public static final boolean USE_NAME_TO_SELECT_CONTEXT = false;
public static boolean USE_CPA_IN_BODIES = false;
public static boolean USE_1LEVEL_IN_BODIES = true;
public static boolean DEPENDENT_THRU_READS = true;
public static class SelectiveCPAContext implements Context {
protected final Context base;
private final Map<ContextKey, InstanceKey> parameterObjs;
private final int hashCode;
private static Map<ContextKey, InstanceKey> makeMap(InstanceKey[] x) {
Map<ContextKey, InstanceKey> result = new HashMap<ContextKey, InstanceKey>();
for(int i = 0; i < x.length; i++) {
if (x[i] != null) {
result.put(ContextKey.PARAMETERS[i], x[i]);
}
}
return result;
}
public SelectiveCPAContext(Context base, InstanceKey[] x) {
this(base, makeMap(x));
}
public SelectiveCPAContext(Context base, Map<ContextKey, InstanceKey> parameterObjs) {
this.base = base;
this.parameterObjs = parameterObjs;
hashCode = base.hashCode() ^ parameterObjs.hashCode();
}
public ContextItem get(ContextKey name) {
if (parameterObjs.containsKey(name)) {
return new FilteredPointerKey.SingleInstanceFilter(parameterObjs.get(name));
} else {
return base.get(name);
}
}
public int hashCode() {
return hashCode;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
return other != null &&
getClass().equals(other.getClass()) &&
base.equals(((SelectiveCPAContext)other).base) &&
parameterObjs.equals(((SelectiveCPAContext)other).parameterObjs);
}
}
public class ForInContext extends SelectiveCPAContext {
ForInContext(Context base, InstanceKey obj) {
super(base, Collections.singletonMap(ContextKey.PARAMETERS[index], obj));
}
public ContextItem get(ContextKey key) {
if (FORIN_KEY.equals(key)) {
return FORIN_MARKER;
} else if(FORIN_PARM_INDEX.equals(key)) {
return ContextItem.Value.make(index);
} else {
return super.get(key);
}
}
@Override
public String toString() {
return "for in hack filter for " + get(ContextKey.PARAMETERS[index]) + " over " + this.base;
}
/**
* get the {@link InstanceKey} used to distinguish this context
*/
public InstanceKey getInstanceKey() {
return ((SingleInstanceFilter)get(ContextKey.PARAMETERS[index])).getInstance();
}
}
/**
* A "dummy" for-in context used for callees of a method analyzed in a real
* {@link ForInContext}. The purpose of this class is to clone callees based
* on the same {@link InstanceKey} used for the caller context, but without
* returning a {@link SingleInstanceFilter} {@link ContextItem} that filters
* possible parameter values.
*/
class MarkerForInContext extends ForInContext {
MarkerForInContext(Context base, InstanceKey obj) {
super(base, obj);
}
/**
* Like {@link ForInContext#get(ContextKey)}, but don't return a
* {@link SingleInstanceFilter} for the distinguishing {@link InstanceKey}
*/
@Override
public ContextItem get(ContextKey key) {
final ContextItem contextItem = super.get(key);
return (contextItem instanceof SingleInstanceFilter) ? null : contextItem;
}
/**
* we need to override this method since
* {@link MarkerForInContext#get(ContextKey)} does not return the
* {@link SingleInstanceFilter} containing the {@link InstanceKey}. Instead,
* we invoke {@link ForInContext#get(ContextKey)} from the superclass.
*/
@Override
public InstanceKey getInstanceKey() {
return ((SingleInstanceFilter)super.get(ContextKey.PARAMETERS[index])).getInstance();
}
}
private final ContextSelector base;
// private final ContextSelector oneLevel;
private final int index;
private void collectValues(DefUse du, SSAInstruction inst, MutableIntSet values) {
if (inst instanceof SSAGetInstruction) {
SSAGetInstruction g = (SSAGetInstruction) inst;
values.add(g.getRef());
if (g.getRef() != -1) {
collectValues(du, du.getDef(g.getRef()), values);
}
} else if (inst instanceof AbstractReflectiveGet) {
AbstractReflectiveGet g = (AbstractReflectiveGet) inst;
values.add(g.getObjectRef());
collectValues(du, du.getDef(g.getObjectRef()), values);
values.add(g.getMemberRef());
collectValues(du, du.getDef(g.getMemberRef()), values);
}
}
private IntSet identifyDependentParameters(CGNode caller, CallSiteReference site) {
MutableIntSet dependentParameters = IntSetUtil.make();
SSAAbstractInvokeInstruction inst = caller.getIR().getCalls(site)[0];
DefUse du = caller.getDU();
for(int i = 0; i < inst.getNumberOfParameters(); i++) {
MutableIntSet values = IntSetUtil.make();
values.add(inst.getUse(i));
if (DEPENDENT_THRU_READS) {
collectValues(du, du.getDef(inst.getUse(i)), values);
}
if (values.contains(index+1)) {
dependentParameters.add(i);
}
}
return dependentParameters;
}
public ForInContextSelector(ContextSelector base) {
this(2, base);
}
public ForInContextSelector(int index, ContextSelector base) {
this.index = index;
this.base = base;
// this.oneLevel = new OneLevelSiteContextSelector(base);
}
private final HashMap<MethodReference, Boolean> forInOnFirstArg_cache = HashMapFactory.make();
private final HashMap<MethodReference, DefUse> du_cache = HashMapFactory.make();
private final IRFactory<IMethod> factory = AstIRFactory.makeDefaultFactory();
// determine whether the method performs a for-in loop over the properties of its index'th argument
@SuppressWarnings("unused")
private boolean forInOnFirstArg(IMethod method) {
MethodReference mref = method.getReference();
if(method.getNumberOfParameters() < index)
return false;
Boolean b = forInOnFirstArg_cache.get(mref);
if(b != null)
return b;
DefUse du = getDefUse(method);
for(SSAInstruction use : Iterator2Iterable.make(du.getUses(index+1))) {
if(use instanceof EachElementGetInstruction) {
forInOnFirstArg_cache.put(mref, true);
return true;
}
}
forInOnFirstArg_cache.put(mref, false);
return false;
}
private DefUse getDefUse(IMethod method) {
MethodReference mref = method.getReference();
DefUse du = du_cache.get(mref);
if(du == null) {
IR ir = factory.makeIR(method, Everywhere.EVERYWHERE, SSAOptions.defaultOptions());
du_cache.put(mref, du = new DefUse(ir));
}
return du;
}
private enum Frequency { NEVER, SOMETIMES, ALWAYS };
private final HashMap<MethodReference, Frequency> usesFirstArgAsPropertyName_cache = HashMapFactory.make();
// determine whether the method never/sometimes/always uses its first argument as a property name
private Frequency usesFirstArgAsPropertyName(IMethod method) {
MethodReference mref = method.getReference();
if(method.getNumberOfParameters() < index)
return Frequency.NEVER;
Frequency f = usesFirstArgAsPropertyName_cache.get(mref);
if(f != null)
return f;
boolean usedAsPropertyName = false, usedAsSomethingElse = false;
DefUse du = getDefUse(method);
for(SSAInstruction use : Iterator2Iterable.make(du.getUses(index+1))) {
if(use instanceof ReflectiveMemberAccess) {
ReflectiveMemberAccess rma = (ReflectiveMemberAccess)use;
if(rma.getMemberRef() == index+1) {
usedAsPropertyName = true;
continue;
}
} else if(use instanceof AstIsDefinedInstruction) {
AstIsDefinedInstruction aidi = (AstIsDefinedInstruction)use;
if(aidi.getNumberOfUses() > 1 && aidi.getUse(1) == index+1) {
usedAsPropertyName = true;
continue;
}
}
usedAsSomethingElse = true;
}
if(!usedAsPropertyName)
f = Frequency.NEVER;
else if(usedAsSomethingElse)
f = Frequency.SOMETIMES;
else
f = Frequency.ALWAYS;
usesFirstArgAsPropertyName_cache.put(mref, f);
return f;
}
// simulate effect of ToString conversion on key
private InstanceKey simulateToString(IClassHierarchy cha, InstanceKey key) {
IClass stringClass = cha.lookupClass(JavaScriptTypes.String);
IClass numberClass = cha.lookupClass(JavaScriptTypes.Number);
if(key instanceof ConstantKey) {
Object value = ((ConstantKey)key).getValue();
if(value instanceof String) {
return key;
} else if(value instanceof Number) {
Double dval = ((Number)value).doubleValue();
return new ConstantKey<Double>(dval, numberClass);
} else if(value instanceof Boolean) {
Boolean bval = (Boolean)value;
return new ConstantKey<String>(bval.toString(), stringClass);
} else if(value == null) {
return new ConstantKey<String>("null", stringClass);
}
} /*else if(key != null && key.getConcreteType() == numberClass) {
return key;
}*/
return new ConcreteTypeKey(stringClass);
}
public Context getCalleeTarget(CGNode caller, CallSiteReference site, IMethod callee, final InstanceKey[] receiver) {
Context baseContext = base.getCalleeTarget(caller, site, callee, receiver);
String calleeFullName = callee.getDeclaringClass().getName().toString();
String calleeShortName = calleeFullName.substring(calleeFullName.lastIndexOf('/')+1);
if(USE_NAME_TO_SELECT_CONTEXT) {
if(calleeShortName.contains(HACK_METHOD_STR) && receiver.length > index) {
// we assume that the argument is only used as a property name, so we can do ToString
return new ForInContext(baseContext, simulateToString(caller.getClassHierarchy(), receiver[index]));
}
} else if(receiver.length > index) {
Frequency f = usesFirstArgAsPropertyName(callee);
/*
if(f == Frequency.ALWAYS) {
return new ForInContext(baseContext, simulateToString(caller.getClassHierarchy(), receiver[index]));
} else if(f == Frequency.SOMETIMES) {
*/
if(receiver[index] == null) {
IClass undef = caller.getClassHierarchy().lookupClass(JavaScriptTypes.Undefined);
return new ForInContext(baseContext, new ConcreteTypeKey(undef));
} else {
return new ForInContext(baseContext, receiver[index]);
}
//}
}
if (USE_CPA_IN_BODIES && FORIN_MARKER.equals(caller.getContext().get(FORIN_KEY))) {
return new SelectiveCPAContext(baseContext, receiver);
} else if (USE_1LEVEL_IN_BODIES && FORIN_MARKER.equals(caller.getContext().get(FORIN_KEY))) {
if (! identifyDependentParameters(caller, site).isEmpty()) {
// final Context calleeTarget = oneLevel.getCalleeTarget(caller, site, callee, receiver);
// // RECURSION CHECK: only add one level of caller-site contexts if the caller and callee methods are distinct
// if (!RecursionCheckContextSelector.recursiveContext(calleeTarget, callee)) {
// return calleeTarget;
// }
// use a MarkerForInContext to clone based on the InstanceKey used in the caller context
// TODO the cast below isn't safe; fix
InstanceKey callerIk = ((ForInContext)caller.getContext()).getInstanceKey();
return new MarkerForInContext(baseContext, callerIk);
} else {
return baseContext;
}
}
return baseContext;
}
public IntSet getRelevantParameters(CGNode caller, CallSiteReference site) {
if (USE_CPA_IN_BODIES && FORIN_MARKER.equals(caller.getContext().get(FORIN_KEY))) {
// what about base.getRelevantParameters() here?
return identifyDependentParameters(caller, site);
} else if (caller.getIR().getCalls(site)[0].getNumberOfUses() > index) {
return IntSetUtil.make(new int[]{index}).union(base.getRelevantParameters(caller, site));
} else {
return base.getRelevantParameters(caller, site);
}
}
}