From fbbd401c9a95091bd3b6dcbc738e596243406d3d Mon Sep 17 00:00:00 2001
From: msridhar1 <msridhar1@f5eafffb-2e1d-0410-98e4-8ec43c5233c4>
Date: Fri, 6 Jan 2012 21:42:47 +0000
Subject: [PATCH] Added optional object sensitivity for functions returning
 'this'.

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@4384 f5eafffb-2e1d-0410-98e4-8ec43c5233c4
---
 .../ipa/callgraph/JSZeroOrOneXCFABuilder.java |  4 +
 .../ObjectSensitivityContextSelector.java     | 95 +++++++++++++++++++
 2 files changed, 99 insertions(+)
 mode change 100644 => 100755 com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/JSZeroOrOneXCFABuilder.java
 create mode 100755 com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/ObjectSensitivityContextSelector.java

diff --git a/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/JSZeroOrOneXCFABuilder.java b/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/JSZeroOrOneXCFABuilder.java
old mode 100644
new mode 100755
index 0c296b2e7..f6500096a
--- a/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/JSZeroOrOneXCFABuilder.java
+++ b/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/JSZeroOrOneXCFABuilder.java
@@ -31,6 +31,7 @@ import com.ibm.wala.ipa.cha.IClassHierarchy;
 public class JSZeroOrOneXCFABuilder extends JSCFABuilder {
 
   private static final boolean HANDLE_FUNCTION_APPLY = true;
+  private static final boolean USE_OBJECT_SENSITIVITY = true;
 
   public JSZeroOrOneXCFABuilder(IClassHierarchy cha, AnalysisOptions options, AnalysisCache cache,
       ContextSelector appContextSelector, SSAContextInterpreter appContextInterpreter, int instancePolicy, boolean doOneCFA) {
@@ -51,6 +52,9 @@ public class JSZeroOrOneXCFABuilder extends JSCFABuilder {
     ContextSelector contextSelector = appContextSelector == null ? def : new DelegatingContextSelector(appContextSelector, def);
     contextSelector = new ScopeMappingKeysContextSelector(contextSelector);
     contextSelector = new JavaScriptConstructorContextSelector(contextSelector);
+    if (USE_OBJECT_SENSITIVITY) {
+      contextSelector = new ObjectSensitivityContextSelector(contextSelector);
+    }
     if (HANDLE_FUNCTION_APPLY) {
       contextSelector = new JavaScriptFunctionApplyContextSelector(contextSelector);
     }
diff --git a/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/ObjectSensitivityContextSelector.java b/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/ObjectSensitivityContextSelector.java
new file mode 100755
index 000000000..64e57b86d
--- /dev/null
+++ b/com.ibm.wala.cast.js/source/com/ibm/wala/cast/js/ipa/callgraph/ObjectSensitivityContextSelector.java
@@ -0,0 +1,95 @@
+package com.ibm.wala.cast.js.ipa.callgraph;
+
+import java.util.HashMap;
+
+import com.ibm.wala.classLoader.CallSiteReference;
+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.FilteredPointerKey;
+import com.ibm.wala.ipa.callgraph.propagation.InstanceKey;
+import com.ibm.wala.ssa.SSAInstruction;
+import com.ibm.wala.ssa.SSAOptions;
+import com.ibm.wala.ssa.SSAReturnInstruction;
+import com.ibm.wala.types.MethodReference;
+import com.ibm.wala.util.collections.HashMapFactory;
+import com.ibm.wala.util.intset.IntSet;
+import com.ibm.wala.util.intset.IntSetUtil;
+
+public class ObjectSensitivityContextSelector implements ContextSelector {
+  private final ContextSelector base;
+  
+  public ObjectSensitivityContextSelector(ContextSelector base) {
+    this.base = base;
+  }
+  
+  private final HashMap<MethodReference, Boolean> returnsThis_cache = HashMapFactory.make();
+  
+  // determine whether the method returns "this"
+  private boolean returnsThis(IMethod method) {
+    MethodReference mref = method.getReference();
+    if(method.getNumberOfParameters() < 1)
+      return false;
+    Boolean b = returnsThis_cache.get(mref);
+    if(b != null)
+      return b;
+    for(SSAInstruction inst : ForInContextSelector.factory.makeIR(method, Everywhere.EVERYWHERE, SSAOptions.defaultOptions()).getInstructions()) {
+      if(inst instanceof SSAReturnInstruction) {
+        SSAReturnInstruction ret = (SSAReturnInstruction)inst;
+        if(ret.getResult() == 2) {
+          returnsThis_cache.put(mref, true);
+          return true;
+        }
+      }
+    }
+    returnsThis_cache.put(mref, false);
+    return false;
+  }
+
+  @Override
+  public Context getCalleeTarget(CGNode caller, CallSiteReference site, IMethod callee, InstanceKey[] arguments) {
+    Context baseContext = base.getCalleeTarget(caller, site, callee, arguments);
+    if(returnsThis(callee)) {
+      if(arguments.length > 1 && arguments[1] != null) {
+        return new ArgumentInstanceContext(baseContext, 1, arguments[1]);
+      }
+    }
+    return baseContext;
+  }
+
+  @Override
+  public IntSet getRelevantParameters(CGNode caller, CallSiteReference site) {
+    if (caller.getIR().getCalls(site)[0].getNumberOfUses() > 1) {
+      return IntSetUtil.make(new int[]{1}).union(base.getRelevantParameters(caller, site));
+    } else {
+      return base.getRelevantParameters(caller, site);
+    }
+  }
+
+}
+
+class ArgumentInstanceContext implements Context {
+  private final Context base;
+  private final int index;
+  private final InstanceKey instanceKey;
+
+  public ArgumentInstanceContext(Context base, int index, InstanceKey instanceKey) {
+    this.base = base;
+    this.index = index;
+    this.instanceKey = instanceKey;
+  }
+
+  @Override
+  public ContextItem get(ContextKey name) {
+    /*if(name == ContextKey.RECEIVER && index == 1)
+      return instanceKey;*/
+    if(name == ContextKey.PARAMETERS[index])
+      return new FilteredPointerKey.SingleInstanceFilter(instanceKey);
+    return base.get(name);
+  }
+  
+}
\ No newline at end of file