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refactoring to allow for varying handling of recursion 

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@2513 f5eafffb-2e1d-0410-98e4-8ec43c5233c4
This commit is contained in:
msridhar1 2008-01-31 03:41:25 +00:00
parent ddad3a7464
commit bb291e1521
1 changed files with 60 additions and 9 deletions
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69
com.ibm.wala.core/src/com/ibm/wala/demandpa/alg/ContextSensitiveStateMachine.java
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@ -37,6 +37,7 @@
*/
package com.ibm.wala.demandpa.alg;
import java.util.Collection;
import java.util.HashSet;
import com.ibm.wala.demandpa.alg.statemachine.StateMachine;
@ -86,8 +87,8 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
return emptyStack;
}
private final HashSet<CallSiteAndCGNode> recursiveCallSites = HashSetFactory.make();
private final RecursionHandler recursionHandler;
private class CSLabelVisitor implements IFlowLabelVisitor {
final CallStack prevStack;
@ -143,7 +144,7 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
}
private void handleMethodExit(CallSiteAndCGNode callSite) {
if (recursiveCallSites.contains(callSite)) {
if (recursionHandler.isRecursive(callSite)) {
nextState = prevStack;
} else if (prevStack.isEmpty()) {
nextState = prevStack;
@ -160,7 +161,7 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
}
private void handleMethodEntry(CallSiteAndCGNode callSite) {
if (recursiveCallSites.contains(callSite)) {
if (recursionHandler.isRecursive(callSite)) {
// just ignore it; we don't track recursive calls
nextState = prevStack;
} else if (prevStack.contains(callSite)) {
@ -172,11 +173,13 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
CallStack tmpStack = prevStack;
// mark the appropriate call sites as recursive
// and pop them
Collection<CallSiteAndCGNode> newRecursiveSites = HashSetFactory.make();
do {
topCallSite = tmpStack.peek();
recursiveCallSites.add(topCallSite);
newRecursiveSites.add(topCallSite);
tmpStack = tmpStack.pop();
} while (!topCallSite.equals(callSite) && !tmpStack.isEmpty());
recursionHandler.makeRecursive(newRecursiveSites);
// here we throw the states merged exception to indicate
// that recursion was detected
// ideally, we would update all relevant data structures and continue,
@ -216,7 +219,9 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
throw new IllegalArgumentException("not ( prevState instanceof com.ibm.wala.demandpa.alg.CallStack ) ");
}
CallStack prevStack = (CallStack) prevState;
if (!prevStack.isEmpty() && recursiveCallSites.contains(prevStack.peek())) {
if (!prevStack.isEmpty() && recursionHandler.isRecursive(prevStack.peek())) {
// I don't think this is possible anymore
assert false;
// just pop off the call site
return transition(prevStack.pop(), label);
}
@ -226,21 +231,67 @@ public class ContextSensitiveStateMachine implements StateMachine<IFlowLabel> {
if (prevStack != v.nextState && v.nextState != ERROR) {
System.err.println("prev stack " + prevStack);
System.err.println("label " + label);
System.err.println("recursive call sites " + recursiveCallSites);
System.err.println("recursive call sites " + recursionHandler);
System.err.println("next stack " + v.nextState);
}
}
return v.nextState;
}
private ContextSensitiveStateMachine() {
private ContextSensitiveStateMachine(RecursionHandler recursionHandler) {
this.recursionHandler = recursionHandler;
}
public static class Factory implements StateMachineFactory<IFlowLabel> {
private final RecursionHandler prototype;
public Factory(RecursionHandler prototype) {
this.prototype = prototype;
}
public Factory() {
this(new BasicRecursionHandler());
}
public StateMachine<IFlowLabel> make() {
return new ContextSensitiveStateMachine();
return new ContextSensitiveStateMachine(prototype.makeNew());
}
}
public static interface RecursionHandler {
public boolean isRecursive(CallSiteAndCGNode callSite);
public void makeRecursive(Collection<CallSiteAndCGNode> callSites);
/**
* in lieu of creating factories
*/
public RecursionHandler makeNew();
}
/**
* handles method recursion by only collapsing cycles of recursive
* calls observed during analysis
* @author manu
*
*/
public static class BasicRecursionHandler implements RecursionHandler {
private final HashSet<CallSiteAndCGNode> recursiveCallSites = HashSetFactory.make();
public boolean isRecursive(CallSiteAndCGNode callSite) {
return recursiveCallSites.contains(callSite);
}
public void makeRecursive(Collection<CallSiteAndCGNode> callSites) {
recursiveCallSites.addAll(callSites);
}
public RecursionHandler makeNew() {
return new BasicRecursionHandler();
}
}
}