/*******************************************************************************
* Copyright (c) 2002 - 2006 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.ipa.cfg;
import java.util.Iterator;
import java.util.Set;
import com.ibm.wala.cfg.ControlFlowGraph;
import com.ibm.wala.cfg.IBasicBlock;
import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.CallGraph;
import com.ibm.wala.ssa.ISSABasicBlock;
import com.ibm.wala.ssa.SSAAbstractInvokeInstruction;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.util.Predicate;
import com.ibm.wala.util.collections.FilterIterator;
import com.ibm.wala.util.collections.IndiscriminateFilter;
import com.ibm.wala.util.collections.MapIterator;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.debug.UnimplementedError;
import com.ibm.wala.util.functions.Function;
import com.ibm.wala.util.graph.NumberedGraph;
import com.ibm.wala.util.graph.impl.SlowSparseNumberedGraph;
import com.ibm.wala.util.intset.BitVector;
import com.ibm.wala.util.intset.BitVectorIntSet;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.MutableIntSet;
/**
* Interprocedural control-flow graph, constructed lazily.
*/
public abstract class AbstractInterproceduralCFG<T extends ISSABasicBlock> implements NumberedGraph<BasicBlockInContext<T>> {
private static final int DEBUG_LEVEL = 0;
private static final boolean WARN_ON_EAGER_CONSTRUCTION = false;
private static final boolean FAIL_ON_EAGER_CONSTRUCTION = false;
/**
* Should the graph include call-to-return edges? When set to <code>false</code>, the graphs output by {@link IFDSExplorer} look
* incorrect
*/
private final static boolean CALL_TO_RETURN_EDGES = true;
/**
* Graph implementation we delegate to.
*/
final private NumberedGraph<BasicBlockInContext<T>> g = new SlowSparseNumberedGraph<BasicBlockInContext<T>>(2);
/**
* Governing call graph
*/
private final CallGraph cg;
/**
* Filter that determines relevant call graph nodes
*/
private final Predicate<CGNode> relevant;
/**
* a cache: for each node (Basic Block), does that block end in a call?
*/
private final BitVector hasCallVector = new BitVector();
/**
* CGNodes whose intraprocedural edges have been added to IPCFG
*/
private MutableIntSet cgNodesVisited = new BitVectorIntSet();
/**
* those cg nodes whose edges to callers have been added
*/
private MutableIntSet cgNodesWithCallerEdges = new BitVectorIntSet();
/**
* those call nodes whose successor edges (interprocedural) have been added
*/
private MutableIntSet handledCalls = new BitVectorIntSet();
/**
* those return nodes whose predecessor edges (interprocedural) have been added
*/
private MutableIntSet handledReturns = new BitVectorIntSet();
/**
* those nodes whose successor edges (intra- and inter-procedural) have been added
*/
private MutableIntSet addedSuccs = new BitVectorIntSet();
/**
* those nodes whose predecessor edges (intra- and inter-procedural) have been added
*/
private MutableIntSet addedPreds = new BitVectorIntSet();
/**
* Should be invoked when the underlying call graph has changed. This will cause certain successor and predecessor edges to be
* recomputed. USE WITH EXTREME CARE.
*/
public void callGraphUpdated() {
cgNodesVisited = new BitVectorIntSet();
cgNodesWithCallerEdges = new BitVectorIntSet();
handledCalls = new BitVectorIntSet();
handledReturns = new BitVectorIntSet();
addedSuccs = new BitVectorIntSet();
addedPreds = new BitVectorIntSet();
}
public abstract ControlFlowGraph<SSAInstruction, T> getCFG(CGNode n);
/**
* Build an Interprocedural CFG from a call graph. This version defaults to using whatever CFGs the call graph provides by
* default, and includes all nodes in the call graph.
*
* @param cg the call graph
*/
public AbstractInterproceduralCFG(CallGraph cg) {
this(cg, IndiscriminateFilter.<CGNode> singleton());
}
/**
* Build an Interprocedural CFG from a call graph.
*
* @param CG the call graph
* @param relevant a filter which accepts those call graph nodes which should be included in the I-CFG. Other nodes are ignored.
*/
public AbstractInterproceduralCFG(CallGraph CG, Predicate<CGNode> relevant) {
this.cg = CG;
this.relevant = relevant;
}
/**
* If n is relevant and its cfg has not already been added, add nodes and edges for n
*
* @param n
*/
private void addIntraproceduralNodesAndEdgesForCGNodeIfNeeded(CGNode n) {
if (!cgNodesVisited.contains(cg.getNumber(n)) && relevant.test(n)) {
if (DEBUG_LEVEL > 0) {
System.err.println("Adding nodes and edges for cg node: " + n);
}
cgNodesVisited.add(cg.getNumber(n));
// retrieve a cfg for node n.
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(n);
if (cfg != null) {
// create a node for each basic block.
addNodeForEachBasicBlock(cfg, n);
SSAInstruction[] instrs = cfg.getInstructions();
// create edges for node n.
for (Iterator<T> bbs = cfg.iterator(); bbs.hasNext();) {
T bb = bbs.next();
if (bb != cfg.entry())
addEdgesToNonEntryBlock(n, cfg, instrs, bb);
}
}
}
}
/**
* Add edges to the IPCFG for the incoming edges incident on a basic block bb.
*
* @param n a call graph node
* @param cfg the CFG for n
* @param instrs the instructions for node n
* @param bb a basic block in the CFG
*/
protected void addEdgesToNonEntryBlock(CGNode n, ControlFlowGraph<?, T> cfg, SSAInstruction[] instrs, T bb) {
if (DEBUG_LEVEL > 1) {
System.err.println("addEdgesToNonEntryBlock: " + bb);
System.err.println("nPred: " + cfg.getPredNodeCount(bb));
}
for (Iterator<? extends T> ps = cfg.getPredNodes(bb); ps.hasNext();) {
T pb = ps.next();
if (DEBUG_LEVEL > 1) {
System.err.println("Consider previous block: " + pb);
}
if (pb.equals(cfg.entry())) {
// entry block has no instructions
BasicBlockInContext<T> p = new BasicBlockInContext<T>(n, pb);
BasicBlockInContext<T> b = new BasicBlockInContext<T>(n, bb);
g.addEdge(p, b);
continue;
}
SSAInstruction inst = getLastInstructionForBlock(pb, instrs);
if (DEBUG_LEVEL > 1) {
System.err.println("Last instruction is : " + inst);
}
if (inst instanceof SSAAbstractInvokeInstruction) {
if (CALL_TO_RETURN_EDGES) {
// Add a "normal" edge from the predecessor block to this block.
BasicBlockInContext<T> p = new BasicBlockInContext<T>(n, pb);
BasicBlockInContext<T> b = new BasicBlockInContext<T>(n, bb);
g.addEdge(p, b);
}
} else {
// previous instruction is not a call instruction.
BasicBlockInContext<T> p = new BasicBlockInContext<T>(n, pb);
BasicBlockInContext<T> b = new BasicBlockInContext<T>(n, bb);
if (!g.containsNode(p) || !g.containsNode(b)) {
assert g.containsNode(p) : "IPCFG does not contain " + p;
assert g.containsNode(b) : "IPCFG does not contain " + b;
}
g.addEdge(p, b);
}
}
}
protected SSAInstruction getLastInstructionForBlock(T pb, SSAInstruction[] instrs) {
int index = pb.getLastInstructionIndex();
SSAInstruction inst = instrs[index];
return inst;
}
/**
* Add an edge from the exit() block of a callee to a return site in the caller
*
* @param returnBlock the return site for a call
* @param targetCFG the called method
*/
private void addEdgesFromExitToReturn(CGNode caller, T returnBlock, CGNode target,
ControlFlowGraph<SSAInstruction, ? extends T> targetCFG) {
T texit = targetCFG.exit();
BasicBlockInContext<T> exit = new BasicBlockInContext<T>(target, texit);
addNodeForBasicBlockIfNeeded(exit);
BasicBlockInContext<T> ret = new BasicBlockInContext<T>(caller, returnBlock);
if (!g.containsNode(exit) || !g.containsNode(ret)) {
assert g.containsNode(exit) : "IPCFG does not contain " + exit;
assert g.containsNode(ret) : "IPCFG does not contain " + ret;
}
if (DEBUG_LEVEL > 1) {
System.err.println("addEdgeFromExitToReturn " + exit + ret);
}
g.addEdge(exit, ret);
}
/**
* Add an edge from the exit() block of a callee to a return site in the caller
*
* @param callBlock the return site for a call
* @param targetCFG the called method
*/
private void addEdgesFromCallToEntry(CGNode caller, T callBlock, CGNode target,
ControlFlowGraph<SSAInstruction, ? extends T> targetCFG) {
T tentry = targetCFG.entry();
BasicBlockInContext<T> entry = new BasicBlockInContext<T>(target, tentry);
addNodeForBasicBlockIfNeeded(entry);
BasicBlockInContext<T> call = new BasicBlockInContext<T>(caller, callBlock);
if (!g.containsNode(entry) || !g.containsNode(call)) {
assert g.containsNode(entry) : "IPCFG does not contain " + entry;
assert g.containsNode(call) : "IPCFG does not contain " + call;
}
if (DEBUG_LEVEL > 1) {
System.err.println("addEdgeFromCallToEntry " + call + " " + entry);
}
g.addEdge(call, entry);
}
/**
* Add the incoming edges to the entry() block and the outgoing edges from the exit() block for a call graph node.
*
* @param n a node in the call graph
* @param bb the entry() block for n
*/
private void addInterproceduralEdgesForEntryAndExitBlocks(CGNode n, ControlFlowGraph<SSAInstruction, ? extends T> cfg) {
T entryBlock = cfg.entry();
T exitBlock = cfg.exit();
if (DEBUG_LEVEL > 0) {
System.err.println("addInterproceduralEdgesForEntryAndExitBlocks " + n);
}
for (Iterator callers = cg.getPredNodes(n); callers.hasNext();) {
CGNode caller = (CGNode) callers.next();
if (DEBUG_LEVEL > 1) {
System.err.println("got caller " + caller);
}
if (relevant.test(caller)) {
addEntryAndExitEdgesToCaller(n, entryBlock, exitBlock, caller);
}
}
}
private void addEntryAndExitEdgesToCaller(CGNode n, T entryBlock, T exitBlock, CGNode caller) {
if (DEBUG_LEVEL > 0) {
System.err.println("caller " + caller + "is relevant");
}
ControlFlowGraph<SSAInstruction, T> ccfg = getCFG(caller);
if (ccfg != null) {
SSAInstruction[] cinsts = ccfg.getInstructions();
if (DEBUG_LEVEL > 1) {
System.err.println("Visiting " + cinsts.length + " instructions");
}
for (int i = 0; i < cinsts.length; i++) {
if (cinsts[i] instanceof SSAAbstractInvokeInstruction) {
if (DEBUG_LEVEL > 1) {
System.err.println("Checking invokeinstruction: " + cinsts[i]);
}
SSAAbstractInvokeInstruction call = (SSAAbstractInvokeInstruction) cinsts[i];
CallSiteReference site = call.getCallSite();
assert site.getProgramCounter() == ccfg.getProgramCounter(i);
if (cg.getPossibleTargets(caller, site).contains(n)) {
if (DEBUG_LEVEL > 1) {
System.err.println("Adding edge " + ccfg.getBlockForInstruction(i) + " to " + entryBlock);
}
T callerBB = ccfg.getBlockForInstruction(i);
BasicBlockInContext<T> b1 = new BasicBlockInContext<T>(caller, callerBB);
// need to add a node for caller basic block, in case we haven't processed caller yet
addNodeForBasicBlockIfNeeded(b1);
BasicBlockInContext<T> b2 = new BasicBlockInContext<T>(n, entryBlock);
g.addEdge(b1, b2);
// also add edges from exit node to all return nodes (successor of call bb)
for (Iterator<? extends T> succIter = ccfg.getSuccNodes(callerBB); succIter.hasNext();) {
T returnBB = succIter.next();
BasicBlockInContext<T> b3 = new BasicBlockInContext<T>(n, exitBlock);
BasicBlockInContext<T> b4 = new BasicBlockInContext<T>(caller, returnBB);
addNodeForBasicBlockIfNeeded(b4);
g.addEdge(b3, b4);
}
}
}
}
}
}
/**
* Add a node to the IPCFG for each node in a CFG. side effect: populates the hasCallVector
*
* @param cfg a control-flow graph
*/
private void addNodeForEachBasicBlock(ControlFlowGraph<? extends SSAInstruction, ? extends T> cfg, CGNode N) {
for (Iterator<? extends T> bbs = cfg.iterator(); bbs.hasNext();) {
T bb = bbs.next();
if (DEBUG_LEVEL > 1) {
System.err.println("IPCFG Add basic block " + bb);
}
BasicBlockInContext<T> b = new BasicBlockInContext<T>(N, bb);
addNodeForBasicBlockIfNeeded(b);
}
}
private void addNodeForBasicBlockIfNeeded(BasicBlockInContext<T> b) {
if (!g.containsNode(b)) {
g.addNode(b);
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(b);
if (hasCall(b, cfg)) {
hasCallVector.set(g.getNumber(b));
}
}
}
/**
* @return the original CFG from whence B came
* @throws IllegalArgumentException if B == null
*/
public ControlFlowGraph<SSAInstruction, T> getCFG(BasicBlockInContext B) throws IllegalArgumentException {
if (B == null) {
throw new IllegalArgumentException("B == null");
}
return getCFG(getCGNode(B));
}
/**
* @return the original CGNode from whence B came
* @throws IllegalArgumentException if B == null
*/
public CGNode getCGNode(BasicBlockInContext B) throws IllegalArgumentException {
if (B == null) {
throw new IllegalArgumentException("B == null");
}
return B.getNode();
}
/*
* @see com.ibm.wala.util.graph.Graph#removeNodeAndEdges(com.ibm.wala.util.graph.Node)
*/
@Override
public void removeNodeAndEdges(BasicBlockInContext N) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
/*
* @see com.ibm.wala.util.graph.NodeManager#iterateNodes()
*/
@Override
public Iterator<BasicBlockInContext<T>> iterator() {
if (WARN_ON_EAGER_CONSTRUCTION) {
System.err.println("WARNING: forcing full ICFG construction by calling iterator()");
}
if (FAIL_ON_EAGER_CONSTRUCTION) {
throw new UnimplementedError();
}
constructFullGraph();
return g.iterator();
}
/*
* @see com.ibm.wala.util.graph.NodeManager#getNumberOfNodes()
*/
@Override
public int getNumberOfNodes() {
if (WARN_ON_EAGER_CONSTRUCTION) {
System.err.println("WARNING: forcing full ICFG construction by calling getNumberOfNodes()");
}
if (FAIL_ON_EAGER_CONSTRUCTION) {
throw new UnimplementedError();
}
constructFullGraph();
return g.getNumberOfNodes();
}
private boolean constructedFullGraph = false;
private void constructFullGraph() {
if (!constructedFullGraph) {
for (CGNode n : cg) {
addIntraproceduralNodesAndEdgesForCGNodeIfNeeded(n);
addEdgesToCallees(n);
}
for (int i = 0; i < g.getMaxNumber(); i++) {
addedSuccs.add(i);
addedPreds.add(i);
}
constructedFullGraph = true;
}
}
/**
* add interprocedural edges to nodes in callees of n
*
* @param n
*/
private void addEdgesToCallees(CGNode n) {
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(n);
if (cfg != null) {
for (Iterator<T> bbs = cfg.iterator(); bbs.hasNext();) {
T bb = bbs.next();
BasicBlockInContext<T> block = new BasicBlockInContext<T>(n, bb);
if (hasCall(block)) {
addCalleeEdgesForCall(n, block);
}
}
}
}
/**
* add edges to callees for return block and corresponding call block(s)
*/
private void addCalleeEdgesForReturn(CGNode node, BasicBlockInContext<T> returnBlock) {
final int num = g.getNumber(returnBlock);
if (!handledReturns.contains(num)) {
handledReturns.add(num);
// compute calls for return
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(returnBlock);
for (Iterator<? extends T> it = cfg.getPredNodes(returnBlock.getDelegate()); it.hasNext();) {
T b = it.next();
final BasicBlockInContext<T> block = new BasicBlockInContext<T>(node, b);
if (hasCall(block)) {
addCalleeEdgesForCall(node, block);
}
}
}
}
/**
* add edges to callee entry for call block, and edges from callee exit to corresponding return blocks
*/
private void addCalleeEdgesForCall(CGNode n, BasicBlockInContext<T> callBlock) {
int num = g.getNumber(callBlock);
if (!handledCalls.contains(num)) {
handledCalls.add(num);
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(n);
CallSiteReference site = getCallSiteForCallBlock(callBlock, cfg);
if (DEBUG_LEVEL > 1) {
System.err.println("got Site: " + site);
}
boolean irrelevantTargets = false;
for (Iterator ts = cg.getPossibleTargets(n, site).iterator(); ts.hasNext();) {
CGNode tn = (CGNode) ts.next();
if (!relevant.test(tn)) {
if (DEBUG_LEVEL > 1) {
System.err.println("Irrelevant target: " + tn);
}
irrelevantTargets = true;
continue;
}
if (DEBUG_LEVEL > 1) {
System.err.println("Relevant target: " + tn);
}
// add an edge from tn exit to this node
ControlFlowGraph<SSAInstruction, ? extends T> tcfg = getCFG(tn);
// tcfg might be null if tn is an unmodelled native method
if (tcfg != null) {
final T cbDelegate = callBlock.getDelegate();
addEdgesFromCallToEntry(n, cbDelegate, tn, tcfg);
for (Iterator<? extends T> returnBlocks = cfg.getSuccNodes(cbDelegate); returnBlocks.hasNext();) {
T retBlock = returnBlocks.next();
addEdgesFromExitToReturn(n, retBlock, tn, tcfg);
if (irrelevantTargets) {
// Add a "normal" edge from the call block to the return block.
g.addEdge(callBlock, new BasicBlockInContext<T>(n, retBlock));
}
}
}
}
}
}
/**
* add edges to nodes in callers of n
*
* @param n
*/
private void addCallerEdges(CGNode n) {
final int num = cg.getNumber(n);
if (!cgNodesWithCallerEdges.contains(num)) {
cgNodesWithCallerEdges.add(num);
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(n);
addInterproceduralEdgesForEntryAndExitBlocks(n, cfg);
}
}
/*
* @see com.ibm.wala.util.graph.NodeManager#addNode(com.ibm.wala.util.graph.Node)
*/
@Override
public void addNode(BasicBlockInContext n) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
/*
* @see com.ibm.wala.util.graph.NodeManager#removeNode(com.ibm.wala.util.graph.Node)
*/
@Override
public void removeNode(BasicBlockInContext n) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#getPredNodes(com.ibm.wala.util.graph.Node)
*/
@Override
public Iterator<BasicBlockInContext<T>> getPredNodes(BasicBlockInContext<T> N) {
initForPred(N);
return g.getPredNodes(N);
}
/**
* add enough nodes and edges to the graph to allow for computing predecessors of N
*/
private void initForPred(BasicBlockInContext<T> N) {
CGNode node = getCGNode(N);
addIntraproceduralNodesAndEdgesForCGNodeIfNeeded(node);
int num = g.getNumber(N);
if (!addedPreds.contains(num)) {
addedPreds.add(num);
if (N.getDelegate().isEntryBlock()) {
addCallerEdges(node);
}
if (isReturn(N)) {
addCalleeEdgesForReturn(node, N);
}
}
}
/**
* add enough nodes and edges to the graph to allow for computing successors of N
*/
private void initForSucc(BasicBlockInContext<T> N) {
CGNode node = getCGNode(N);
addIntraproceduralNodesAndEdgesForCGNodeIfNeeded(node);
int num = g.getNumber(N);
if (!addedSuccs.contains(num)) {
addedSuccs.add(num);
if (N.getDelegate().isExitBlock()) {
addCallerEdges(node);
}
if (hasCall(N)) {
addCalleeEdgesForCall(node, N);
}
}
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#getPredNodeCount(com.ibm.wala.util.graph.Node)
*/
@Override
public int getPredNodeCount(BasicBlockInContext<T> N) {
initForPred(N);
return g.getPredNodeCount(N);
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#getSuccNodes(com.ibm.wala.util.graph.Node)
*/
@Override
public Iterator<BasicBlockInContext<T>> getSuccNodes(BasicBlockInContext<T> N) {
initForSucc(N);
return g.getSuccNodes(N);
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#getSuccNodeCount(com.ibm.wala.util.graph.Node)
*/
@Override
public int getSuccNodeCount(BasicBlockInContext<T> N) {
initForSucc(N);
return g.getSuccNodeCount(N);
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#addEdge(com.ibm.wala.util.graph.Node, com.ibm.wala.util.graph.Node)
*/
@Override
public void addEdge(BasicBlockInContext src, BasicBlockInContext dst) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
@Override
public void removeEdge(BasicBlockInContext src, BasicBlockInContext dst) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
/*
* @see com.ibm.wala.util.graph.EdgeManager#removeEdges(com.ibm.wala.util.graph.Node)
*/
@Override
public void removeAllIncidentEdges(BasicBlockInContext node) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
@Override
public String toString() {
return g.toString();
}
/*
* @see com.ibm.wala.util.graph.Graph#containsNode(com.ibm.wala.util.graph.Node)
*/
@Override
public boolean containsNode(BasicBlockInContext<T> N) {
return g.containsNode(N);
}
/**
* @param B
* @return true iff basic block B ends in a call instuction
*/
public boolean hasCall(BasicBlockInContext<T> B) {
addNodeForBasicBlockIfNeeded(B);
return hasCallVector.get(getNumber(B));
}
/**
* @return true iff basic block B ends in a call instuction
*/
protected boolean hasCall(BasicBlockInContext<T> B, ControlFlowGraph<SSAInstruction, T> cfg) {
SSAInstruction[] statements = cfg.getInstructions();
int lastIndex = B.getLastInstructionIndex();
if (lastIndex >= 0) {
if (statements.length <= lastIndex) {
System.err.println(statements.length);
System.err.println(cfg);
assert lastIndex < statements.length : "bad BB " + B + " and CFG for " + getCGNode(B);
}
SSAInstruction last = statements[lastIndex];
return (last instanceof SSAAbstractInvokeInstruction);
} else {
return false;
}
}
/**
* @param B
* @return the set of CGNodes that B may call, according to the governing call graph.
* @throws IllegalArgumentException if B is null
*/
public Set<CGNode> getCallTargets(BasicBlockInContext<T> B) {
if (B == null) {
throw new IllegalArgumentException("B is null");
}
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(B);
return getCallTargets(B, cfg, getCGNode(B));
}
/**
* @return the set of CGNodes that B may call, according to the governing call graph.
*/
private Set<CGNode> getCallTargets(IBasicBlock<SSAInstruction> B, ControlFlowGraph<SSAInstruction, T> cfg, CGNode Bnode) {
CallSiteReference site = getCallSiteForCallBlock(B, cfg);
return cg.getPossibleTargets(Bnode, site);
}
/**
* get the {@link CallSiteReference} corresponding to the last instruction in B (assumed to be a call)
*/
protected CallSiteReference getCallSiteForCallBlock(IBasicBlock<SSAInstruction> B, ControlFlowGraph<SSAInstruction, T> cfg) {
SSAInstruction[] statements = cfg.getInstructions();
SSAAbstractInvokeInstruction call = (SSAAbstractInvokeInstruction) statements[B.getLastInstructionIndex()];
int pc = cfg.getProgramCounter(B.getLastInstructionIndex());
CallSiteReference site = call.getCallSite();
assert site.getProgramCounter() == pc;
return site;
}
@Override
public void removeIncomingEdges(BasicBlockInContext node) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
@Override
public void removeOutgoingEdges(BasicBlockInContext node) throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
@Override
public boolean hasEdge(BasicBlockInContext<T> src, BasicBlockInContext<T> dst) {
if (!addedSuccs.contains(getNumber(src))) {
if (!src.getNode().equals(dst.getNode())) {
if (src.getDelegate().isExitBlock()) {
// checking for an exit to return edge
CGNode callee = src.getNode();
if (!cgNodesWithCallerEdges.contains(cg.getNumber(callee))) {
CGNode caller = dst.getNode();
T exitBlock = src.getDelegate();
T entryBlock = getCFG(callee).entry();
addEntryAndExitEdgesToCaller(callee, entryBlock, exitBlock, caller);
}
} else if (hasCall(src) && dst.getDelegate().isEntryBlock()) {
// checking for a call to entry edge
CGNode callee = dst.getNode();
if (!cgNodesWithCallerEdges.contains(cg.getNumber(callee))) {
CGNode caller = src.getNode();
T entryBlock = dst.getDelegate();
T exitBlock = getCFG(callee).exit();
addEntryAndExitEdgesToCaller(callee, entryBlock, exitBlock, caller);
}
}
} else {
// if it exists, edge must be intraprocedural
addIntraproceduralNodesAndEdgesForCGNodeIfNeeded(src.getNode());
}
}
addedSuccs.add(getNumber(src));
return g.hasEdge(src, dst);
}
@Override
public int getNumber(BasicBlockInContext<T> N) {
addNodeForBasicBlockIfNeeded(N);
return g.getNumber(N);
}
@Override
public BasicBlockInContext<T> getNode(int number) throws UnimplementedError {
return g.getNode(number);
}
@Override
public int getMaxNumber() {
if (WARN_ON_EAGER_CONSTRUCTION) {
System.err.println("WARNING: forcing full ICFG construction by calling getMaxNumber()");
}
if (FAIL_ON_EAGER_CONSTRUCTION) {
throw new UnimplementedError();
}
constructFullGraph();
return g.getMaxNumber();
}
@Override
public Iterator<BasicBlockInContext<T>> iterateNodes(IntSet s) throws UnimplementedError {
Assertions.UNREACHABLE();
return null;
}
@Override
public IntSet getSuccNodeNumbers(BasicBlockInContext<T> node) {
initForSucc(node);
return g.getSuccNodeNumbers(node);
}
@Override
public IntSet getPredNodeNumbers(BasicBlockInContext<T> node) {
initForPred(node);
return g.getPredNodeNumbers(node);
}
public BasicBlockInContext<T> getEntry(CGNode n) {
ControlFlowGraph<SSAInstruction, ? extends T> cfg = getCFG(n);
if (cfg != null) {
T entry = cfg.entry();
return new BasicBlockInContext<T>(n, entry);
} else {
return null;
}
}
public BasicBlockInContext<T> getExit(CGNode n) {
ControlFlowGraph<SSAInstruction, ? extends T> cfg = getCFG(n);
T entry = cfg.exit();
return new BasicBlockInContext<T>(n, entry);
}
/**
* @param callBlock node in the IPCFG that ends in a call
* @return the nodes that are return sites for this call.
* @throws IllegalArgumentException if bb is null
*/
public Iterator<BasicBlockInContext<T>> getReturnSites(BasicBlockInContext<T> callBlock) {
if (callBlock == null) {
throw new IllegalArgumentException("bb is null");
}
final CGNode node = callBlock.getNode();
// a successor node is a return site if it is in the same
// procedure, and is not the entry() node.
Predicate isReturn = new Predicate() {
@Override public boolean test(Object o) {
BasicBlockInContext other = (BasicBlockInContext) o;
return !other.isEntryBlock() && node.equals(other.getNode());
}
};
return new FilterIterator<BasicBlockInContext<T>>(getSuccNodes(callBlock), isReturn);
}
/**
* get the basic blocks which are call sites that may call callee and return to returnBlock if callee is null, answer return sites
* for which no callee was found.
*/
public Iterator<BasicBlockInContext<T>> getCallSites(BasicBlockInContext<T> returnBlock, final CGNode callee) {
if (returnBlock == null) {
throw new IllegalArgumentException("bb is null");
}
final ControlFlowGraph<SSAInstruction, T> cfg = getCFG(returnBlock);
Iterator<? extends T> it = cfg.getPredNodes(returnBlock.getDelegate());
final CGNode node = returnBlock.getNode();
Predicate<? extends T> dispatchFilter = new Predicate<T>() {
@Override public boolean test(T callBlock) {
BasicBlockInContext<T> bb = new BasicBlockInContext<T>(node, callBlock);
if (!hasCall(bb, cfg)) {
return false;
}
if (callee != null) {
return getCallTargets(bb).contains(callee);
} else {
return getCallTargets(bb).isEmpty();
}
}
};
it = new FilterIterator<T>(it, dispatchFilter);
Function<T, BasicBlockInContext<T>> toContext = new Function<T, BasicBlockInContext<T>>() {
@Override
public BasicBlockInContext<T> apply(T object) {
T b = object;
return new BasicBlockInContext<T>(node, b);
}
};
MapIterator<T, BasicBlockInContext<T>> m = new MapIterator<T, BasicBlockInContext<T>>(it, toContext);
return new FilterIterator<BasicBlockInContext<T>>(m, isCall);
}
private final Predicate<BasicBlockInContext<T>> isCall = new Predicate<BasicBlockInContext<T>>() {
@Override public boolean test(BasicBlockInContext<T> o) {
return hasCall(o);
}
};
public boolean isReturn(BasicBlockInContext<T> bb) throws IllegalArgumentException {
if (bb == null) {
throw new IllegalArgumentException("bb == null");
}
ControlFlowGraph<SSAInstruction, T> cfg = getCFG(bb);
for (Iterator<? extends T> it = cfg.getPredNodes(bb.getDelegate()); it.hasNext();) {
T b = it.next();
if (hasCall(new BasicBlockInContext<T>(bb.getNode(), b))) {
return true;
}
}
return false;
}
/**
* @return the governing {@link CallGraph} used to build this ICFG
*/
public CallGraph getCallGraph() {
return cg;
}
}