/*******************************************************************************
* Copyright (c) 2013 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.analysis.reflection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import com.ibm.wala.cfg.ControlFlowGraph;
import com.ibm.wala.cfg.InducedCFG;
import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.classLoader.NewSiteReference;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.propagation.SSAContextInterpreter;
import com.ibm.wala.ipa.summaries.SyntheticIR;
import com.ibm.wala.ssa.ConstantValue;
import com.ibm.wala.ssa.DefUse;
import com.ibm.wala.ssa.IR;
import com.ibm.wala.ssa.ISSABasicBlock;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.ssa.SSAInstructionFactory;
import com.ibm.wala.ssa.SSAOptions;
import com.ibm.wala.ssa.SSAReturnInstruction;
import com.ibm.wala.types.FieldReference;
import com.ibm.wala.types.MethodReference;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.EmptyIterator;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.collections.NonNullSingletonIterator;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.strings.Atom;
/**
* Understands {@link com.ibm.wala.analysis.reflection.GetMethodContext}.
* @author Michael Heilmann
* @see com.ibm.wala.analysis.reflection.GetMethodContext
* @see com.ibm.wala.analysis.reflection.GetMethodContextSelector
*/
public class GetMethodContextInterpreter implements SSAContextInterpreter {
/**
* TODO
* MH: Maybe hard-code those in {@link com.ibm.wala.types.MethodReference}?
*/
public final static MethodReference GET_METHOD = MethodReference.findOrCreate(TypeReference.JavaLangClass, "getMethod",
"(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;");
/**
* TODO
* MH: Maybe hard-code those in {@link com.ibm.wala.types.MethodReference}?
*/
public final static MethodReference GET_DECLARED_METHOD = MethodReference.findOrCreate(TypeReference.JavaLangClass,
"getDeclaredMethod", "(Ljava/lang/String;[Ljava/lang/Class;)Ljava/lang/reflect/Method;");
private static final boolean DEBUG = false;
/**
* @see com.ibm.wala.ipa.callgraph.propagation.SSAContextInterpreter#getIR(com.ibm.wala.ipa.callgraph.CGNode)
*/
@Override
public IR getIR(CGNode node) {
if (node == null) {
throw new IllegalArgumentException("node is null");
}
assert understands(node);
if (DEBUG) {
System.err.println("generating IR for " + node);
}
IMethod method = node.getMethod();
GetMethodContext context = (GetMethodContext) node.getContext();
Map<Integer,ConstantValue> constants = HashMapFactory.make();
if (method.getReference().equals(GET_METHOD)) {
Atom name = Atom.findOrCreateAsciiAtom(context.getName());
SSAInstruction instrs[] = makeGetMethodStatements(context,constants,name);
return new SyntheticIR(method, context, new InducedCFG(instrs, method, context), instrs, SSAOptions.defaultOptions(), constants);
}
if (method.getReference().equals(GET_DECLARED_METHOD)) {
Atom name = Atom.findOrCreateAsciiAtom(context.getName());
SSAInstruction instrs[] = makeGetDeclaredMethodStatements(context,constants,name);
return new SyntheticIR(method, context, new InducedCFG(instrs, method, context), instrs, SSAOptions.defaultOptions(), constants);
}
Assertions.UNREACHABLE("Unexpected method " + node);
return null;
}
/**
* @see com.ibm.wala.ipa.callgraph.propagation.SSAContextInterpreter#getNumberOfStatements(com.ibm.wala.ipa.callgraph.CGNode)
*/
@Override
public int getNumberOfStatements(CGNode node) {
assert understands(node);
return getIR(node).getInstructions().length;
}
/**
* @see com.ibm.wala.ipa.callgraph.propagation.rta.RTAContextInterpreter#understands(com.ibm.wala.ipa.callgraph.CGNode)
*/
@Override
public boolean understands(CGNode node) {
if (node == null) {
throw new IllegalArgumentException("node is null");
}
if (!(node.getContext() instanceof GetMethodContext)) {
return false;
}
MethodReference mRef = node.getMethod().getReference();
return mRef.equals(GET_METHOD) || mRef.equals(GET_DECLARED_METHOD);
}
@Override
public Iterator<NewSiteReference> iterateNewSites(CGNode node) {
if (node == null) {
throw new IllegalArgumentException("node is null");
}
assert understands(node);
GetMethodContext context = (GetMethodContext) node.getContext();
TypeReference tr = context.getType().getTypeReference();
if (tr != null) {
return new NonNullSingletonIterator<NewSiteReference>(NewSiteReference.make(0, tr));
}
return EmptyIterator.instance();
}
@Override
public Iterator<CallSiteReference> iterateCallSites(CGNode node) {
assert understands(node);
return EmptyIterator.instance();
}
/**
* Get all non-constructor, non-class-initializer methods declared by a class
* if their name is equal to the specified name.
* @param cls the class
* @param name the name
*/
private Collection<IMethod> getDeclaredNormalMethods(IClass cls,Atom name) {
Collection<IMethod> result = HashSetFactory.make();
for (IMethod m : cls.getDeclaredMethods()) {
if (!m.isInit() && !m.isClinit() && m.getSelector().getName().equals(name)) {
result.add(m);
}
}
return result;
}
/**
* Get all non-constructor, non-class-initializer methods declared by a class
* and all its superclasses if their name is equal to the specified name.
* @param cls the class
* @param name the name
*/
private Collection<IMethod> getAllNormalPublicMethods(IClass cls,Atom name) {
Collection<IMethod> result = HashSetFactory.make();
Collection<IMethod> allMethods = null;
allMethods = cls.getAllMethods();
for (IMethod m : allMethods) {
if (!m.isInit() && !m.isClinit() && m.isPublic() && m.getSelector().getName().equals(name)) {
result.add(m);
}
}
return result;
}
/**
* Create statements for methods like getMethod() and getDeclaredMethod(),
* which return a single method. This creates a return statement for each
* possible return value, each of which is a {@link ConstantValue} for an
* {@link IMethod}.
* @param returnValues the possible return values for this method
* @return the statements
*/
private SSAInstruction[] getParticularMethodStatements
(
MethodReference ref,
Collection<IMethod> returnValues,
GetMethodContext context,
Map<Integer, ConstantValue> constants
) {
ArrayList<SSAInstruction> statements = new ArrayList<SSAInstruction>();
int nextLocal = ref.getNumberOfParameters() + 2;
IClass cls = context.getType().getType();
SSAInstructionFactory insts = context.getType().getType().getClassLoader().getInstructionFactory();
if (cls != null) {
for (IMethod m : returnValues) {
int c = nextLocal++;
constants.put(c, new ConstantValue(m));
SSAReturnInstruction R = insts.ReturnInstruction(statements.size(), c, false);
statements.add(R);
}
} else {
// SJF: This is incorrect. TODO: fix and enable.
// SSAThrowInstruction t = insts.ThrowInstruction(retValue);
// statements.add(t);
}
SSAInstruction[] result = new SSAInstruction[statements.size()];
Iterator<SSAInstruction> it = statements.iterator();
for (int i = 0; i < result.length; i++) {
result[i] = it.next();
}
return result;
}
private SSAInstruction[] makeGetMethodStatements
(
GetMethodContext context,
Map<Integer,ConstantValue> constants,
Atom name
) {
IClass cls = context.getType().getType();
if (cls == null) {
return getParticularMethodStatements(GET_METHOD, null, context, constants);
} else {
return getParticularMethodStatements(GET_METHOD, getAllNormalPublicMethods(cls,name), context, constants);
}
}
/**
* Create statements for {@link Class#getDeclaredMethod(String, Class...)}.
*/
private SSAInstruction[] makeGetDeclaredMethodStatements(GetMethodContext context, Map<Integer, ConstantValue> constants,Atom name) {
IClass cls = context.getType().getType();
if (cls == null) {
return getParticularMethodStatements(GET_DECLARED_METHOD, null, context, constants);
} else {
return getParticularMethodStatements(GET_DECLARED_METHOD, getDeclaredNormalMethods(cls,name), context, constants);
}
}
@Override
public boolean recordFactoryType(CGNode node, IClass klass) {
return false;
}
@Override
public Iterator<FieldReference> iterateFieldsRead(CGNode node) {
return EmptyIterator.instance();
}
@Override
public Iterator<FieldReference> iterateFieldsWritten(CGNode node) {
return EmptyIterator.instance();
}
@Override
public ControlFlowGraph<SSAInstruction,ISSABasicBlock> getCFG(CGNode N) {
return getIR(N).getControlFlowGraph();
}
@Override
public DefUse getDU(CGNode node) {
return new DefUse(getIR(node));
}
}