Impl of IMethod.is(Wala)Synthetic and IClass.isSynthetic (#359)

* Impl of IMethod isSynthetic and isWalaSynthetic

So far IMethod.isSynthetic referred to WALA-generated helper functions
and there was no equivalent to check whether an IMethod is synthetic in
terms of compiler-generated.

To make naming consistent this patch first renames the isSynthetic to
isWalaSynthetic to clearly indicate that a given IMethod was generated
by WALA. Then, we re-introduce isSynthetic that from now on checks
whether an IMethod is synthetic/compiler-generated (referring to the
synthetic flag in bytecode)

* Implementation of IClass.isSynthetic

Complementary to IMethod.isSynthetic, this method checks whether
an IClass is compiler-generated.

* updated JavaDoc

com.ibm.wala.cast.java/src/com/ibm/wala/cast/java/ipa/callgraph/AstJavaSSAPropagationCallGraphBuilder.java

@@ -256,7 +256,7 @@ public class AstJavaSSAPropagationCallGraphBuilder extends AstSSAPropagationCall
 
             System.err.println(("class is " + klass + ", enclosing is " + enclosingClass + ", method is " + node.getMethod()));
 
-            if (node.getMethod().isSynthetic()) {
+            if (node.getMethod().isWalaSynthetic()) {
               return;
             }
 

com.ibm.wala.cast/source/java/com/ibm/wala/cast/loader/AstClass.java

@@ -85,6 +85,11 @@ abstract public class AstClass implements IClass, ClassConstants {
     return false;
   }
 
+  @Override
+  public boolean isSynthetic() {
+    return false;
+  }
+
   @Override
   public int getModifiers() {
     return modifiers;

com.ibm.wala.cast/source/java/com/ibm/wala/cast/loader/AstFunctionClass.java

@@ -91,6 +91,11 @@ abstract public class AstFunctionClass implements IClass, ClassConstants {
     return false;
   }
 
+  @Override
+  public boolean isSynthetic() {
+    return false;
+  }
+
   @Override
   public int getModifiers() {
     return ACC_PUBLIC;

com.ibm.wala.cast/source/java/com/ibm/wala/cast/loader/AstMethod.java

@@ -267,6 +267,11 @@ public abstract class AstMethod implements IMethod {
     return qualifiers.contains(CAstQualifier.NATIVE);
   }
 
+  @Override
+  public boolean isWalaSynthetic() {
+    return false;
+  }
+
   @Override
   public boolean isSynthetic() {
     return false;

com.ibm.wala.core/src/com/ibm/wala/analysis/reflection/FactoryBypassInterpreter.java

@@ -141,7 +141,7 @@ public class FactoryBypassInterpreter extends AbstractReflectionInterpreter {
     if (node == null) {
       throw new IllegalArgumentException("node is null");
     }
-    if (node.getMethod().isSynthetic()) {
+    if (node.getMethod().isWalaSynthetic()) {
       SyntheticMethod s = (SyntheticMethod) node.getMethod();
       if (s.isFactoryMethod()) {
         return getTypesForContext(node.getContext()) != null;

com.ibm.wala.core/src/com/ibm/wala/analysis/reflection/FactoryContextSelector.java

@@ -38,7 +38,7 @@ class FactoryContextSelector implements ContextSelector {
     if (callee == null) {
       throw new IllegalArgumentException("callee is null");
     }
-    if (callee.isSynthetic()) {
+    if (callee.isWalaSynthetic()) {
       SyntheticMethod s = (SyntheticMethod) callee;
       if (s.isFactoryMethod()) {
         return new CallStringContext(new CallString(site, caller.getMethod()));

com.ibm.wala.core/src/com/ibm/wala/classLoader/ArrayClass.java

@@ -371,6 +371,11 @@ public class ArrayClass implements IClass, Constants {
     return false;
   }
 
+  @Override
+  public boolean isSynthetic() {
+    return false;
+  }
+
   @Override
   public Reader getSource() {
     return null;

com.ibm.wala.core/src/com/ibm/wala/classLoader/CodeScanner.java

@@ -46,7 +46,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getCallSites(sm.getStatements());
     } else {
@@ -62,7 +62,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getFieldsRead(sm.getStatements());
     } else {
@@ -78,7 +78,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getFieldsWritten(sm.getStatements());
     } else {
@@ -95,7 +95,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getArraysWritten(sm.getStatements());
     } else {
@@ -111,7 +111,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getNewSites(sm.getStatements());
     } else {
@@ -123,7 +123,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return hasObjectArrayLoad(sm.getStatements());
     } else {
@@ -135,7 +135,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return hasObjectArrayStore(sm.getStatements());
     } else {
@@ -147,7 +147,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return getCaughtExceptions(sm.getStatements());
     } else {
@@ -166,7 +166,7 @@ public class CodeScanner {
     if (m == null) {
       throw new IllegalArgumentException("m is null");
     }
-    if (m.isSynthetic()) {
+    if (m.isWalaSynthetic()) {
       SyntheticMethod sm = (SyntheticMethod) m;
       return iterateCastTypes(sm.getStatements());
     } else {

com.ibm.wala.core/src/com/ibm/wala/classLoader/IClass.java

@@ -54,6 +54,11 @@ public interface IClass extends IClassHierarchyDweller {
    */
   boolean isPrivate();
 
+  /**
+   * @return true iff this class is synthetic, i.e., compiler-generated
+   */
+  boolean isSynthetic();
+
   /**
    * Return the integer that encodes the class's modifiers, as defined by the JVM specification
    * 

com.ibm.wala.core/src/com/ibm/wala/classLoader/IMethod.java

@@ -43,7 +43,14 @@ public interface IMethod extends IMember, ContextItem {
   boolean isNative();
 
   /**
-   * Did someone synthesize this method? (As opposed to reading it from a class file)
+   * Is the implementation of this method a model generated by WALA?
+   * For compiler-generated synthetic methods, refer to {@link #isSynthetic()}
+   */
+  boolean isWalaSynthetic();
+
+  /**
+   * Is this method synthetic, i.e., compiler-generated (this refers to the
+   * synthetic flag in java/dex bytecode)
    */
   boolean isSynthetic();
 

com.ibm.wala.core/src/com/ibm/wala/classLoader/JVMClass.java

@@ -65,6 +65,15 @@ public abstract class JVMClass<T extends IClassLoader> extends BytecodeClass<T>
     return result;
   }
 
+  /*
+   * @see com.ibm.wala.classLoader.IClass#isSynthetic()
+   */
+  @Override
+  public boolean isSynthetic() {
+    boolean result = ((modifiers & Constants.ACC_SYNTHETIC) != 0);
+    return result;
+  }
+
   /**
    * @see com.ibm.wala.classLoader.IClass#getClassInitializer()
    */

com.ibm.wala.core/src/com/ibm/wala/classLoader/ShrikeBTMethod.java

@@ -441,7 +441,10 @@ public abstract class ShrikeBTMethod implements IMethod, BytecodeConstants {
   }
 
   @Override
-  public boolean isSynthetic() {
+  public boolean isSynthetic() { return ((getModifiers() & Constants.ACC_SYNTHETIC) != 0); }
+
+  @Override
+  public boolean isWalaSynthetic() {
     return false;
   }
 

com.ibm.wala.core/src/com/ibm/wala/classLoader/SyntheticClass.java

@@ -95,6 +95,16 @@ public abstract class SyntheticClass implements IClass {
     return false;
   }
 
+  /*
+   * These classes are generated by WALA, not by any
+   * compiler, therefore it always returns false
+   * @see com.ibm.wala.classLoader.IClass#isSynthetic()
+   */
+  @Override
+  public boolean isSynthetic() {
+    return false;
+  }
+
   /* 
    * @see com.ibm.wala.classLoader.IClass#getReference()
    */
@@ -123,7 +133,7 @@ public abstract class SyntheticClass implements IClass {
   public boolean isArrayClass() {
     return false;
   }
-  
+
   @Override
   public IClassHierarchy getClassHierarchy() {
     return cha;

com.ibm.wala.core/src/com/ibm/wala/classLoader/SyntheticMethod.java

@@ -153,12 +153,20 @@ public class SyntheticMethod implements IMethod {
     return false;
   }
 
+  /**
+   * @see com.ibm.wala.classLoader.IMethod#isWalaSynthetic()
+   */
+  @Override
+  public boolean isWalaSynthetic() {
+    return true;
+  }
+
   /**
    * @see com.ibm.wala.classLoader.IMethod#isSynthetic()
    */
   @Override
   public boolean isSynthetic() {
-    return true;
+    return false;
   }
 
   /**

com.ibm.wala.core/src/com/ibm/wala/demandpa/util/SimpleMemoryAccessMap.java

@@ -102,7 +102,7 @@ public class SimpleMemoryAccessMap implements MemoryAccessMap {
   private void populate(CGNode n) {
     // we analyze bytecodes to avoid the cost of IR construction, except
     // for synthetic methods, where we must use the synthetic IR
-    if (ALWAYS_BUILD_IR || n.getMethod().isSynthetic()) {
+    if (ALWAYS_BUILD_IR || n.getMethod().isWalaSynthetic()) {
       if (DEBUG) {
         System.err.println("synthetic method");
       }

com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/impl/BasicCallGraph.java

@@ -184,7 +184,7 @@ public abstract class BasicCallGraph<T> extends AbstractNumberedGraph<CGNode> im
     protected NodeImpl(IMethod method, Context C) {
       this.method = method;
       this.context = C;
-      if (method != null && !method.isSynthetic() && method.isAbstract()) {
+      if (method != null && !method.isWalaSynthetic() && method.isAbstract()) {
         assert !method.isAbstract() : "Abstract method " + method;
       }
       assert C != null;

com.ibm.wala.core/src/com/ibm/wala/ipa/callgraph/impl/ExplicitCallGraph.java

@@ -297,7 +297,7 @@ public class ExplicitCallGraph extends BasicCallGraph<SSAContextInterpreter> imp
 
     @Override
     public IR getIR() {
-      if (getMethod().isSynthetic()) {
+      if (getMethod().isWalaSynthetic()) {
         // disable local cache in this case, as context interpreters
         // do weird things like mutate IRs
         return getCallGraph().getInterpreter(this).getIR(this);
@@ -312,7 +312,7 @@ public class ExplicitCallGraph extends BasicCallGraph<SSAContextInterpreter> imp
 
     @Override
     public DefUse getDU() {
-      if (getMethod().isSynthetic()) {
+      if (getMethod().isWalaSynthetic()) {
         // disable local cache in this case, as context interpreters
         // do weird things like mutate IRs
         return getCallGraph().getInterpreter(this).getDU(this);

com.ibm.wala.core/src/com/ibm/wala/ssa/DefaultIRFactory.java

@@ -40,7 +40,7 @@ public class DefaultIRFactory implements IRFactory<IMethod> {
     if (method == null) {
       throw new IllegalArgumentException("method cannot be null");
     }
-    if (method.isSynthetic()) {
+    if (method.isWalaSynthetic()) {
       return syntheticFactory.makeCFG((SyntheticMethod) method);
     } else if (method instanceof IBytecodeMethod) {
       @SuppressWarnings("unchecked")
@@ -61,7 +61,7 @@ public class DefaultIRFactory implements IRFactory<IMethod> {
     if (method == null) {
       throw new IllegalArgumentException("method cannot be null");
     }
-    if (method.isSynthetic()) {
+    if (method.isWalaSynthetic()) {
       return syntheticFactory.makeIR((SyntheticMethod) method, c, options);
     } else if (method instanceof IBytecodeMethod) {
       @SuppressWarnings("unchecked")
@@ -81,7 +81,7 @@ public class DefaultIRFactory implements IRFactory<IMethod> {
     if (method == null) {
       throw new IllegalArgumentException("null method");
     }
-    if (method.isSynthetic()) {
+    if (method.isWalaSynthetic()) {
       return syntheticFactory.contextIsIrrelevant((SyntheticMethod) method);
     } else if (method instanceof ShrikeCTMethod) {
       // we know ShrikeFactory contextIsIrrelevant

com.ibm.wala.dalvik.test/source/com/ibm/wala/dalvik/test/callGraph/JVMLDalvikComparisonTest.java

@@ -63,9 +63,9 @@ public class JVMLDalvikComparisonTest extends DalvikCallGraphTestBase {
 	private static Set<Pair<CGNode,CGNode>> edgeDiff(CallGraph from, CallGraph to, boolean userOnly) {
 		Set<Pair<CGNode,CGNode>> result = HashSetFactory.make();
 		for(CGNode f : from) {
-			if (! f.getMethod().isSynthetic()) {
+			if (! f.getMethod().isWalaSynthetic()) {
 			outer: for(CGNode t : from) {
-				if (!t.getMethod().isSynthetic() && 
+				if (!t.getMethod().isWalaSynthetic() &&
 				    from.hasEdge(f, t) && 
 				    (!userOnly || 
 				     !t.getMethod().getDeclaringClass().getClassLoader().getReference().equals(ClassLoaderReference.Primordial))) 

com.ibm.wala.dalvik/src/com/ibm/wala/dalvik/classLoader/DexIClass.java

@@ -51,6 +51,7 @@ import static org.jf.dexlib2.AccessFlags.ABSTRACT;
 import static org.jf.dexlib2.AccessFlags.INTERFACE;
 import static org.jf.dexlib2.AccessFlags.PRIVATE;
 import static org.jf.dexlib2.AccessFlags.PUBLIC;
+import static org.jf.dexlib2.AccessFlags.SYNTHETIC;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -229,6 +230,13 @@ public class DexIClass extends BytecodeClass<IClassLoader> {
         return (modifiers & ABSTRACT.getValue()) != 0;
     }
 
+    /*
+     * @see com.ibm.wala.classLoader.IClass#isAbstract()
+     */
+    @Override
+    public boolean isSynthetic() {
+        return (modifiers & SYNTHETIC.getValue()) != 0;
+    }
 
     /*
      * (non-Javadoc)

com.ibm.wala.dalvik/src/com/ibm/wala/dalvik/classLoader/DexIMethod.java

@@ -59,6 +59,7 @@ import static org.jf.dexlib2.AccessFlags.PROTECTED;
 import static org.jf.dexlib2.AccessFlags.PUBLIC;
 import static org.jf.dexlib2.AccessFlags.STATIC;
 import static org.jf.dexlib2.AccessFlags.VOLATILE;
+import static org.jf.dexlib2.AccessFlags.SYNTHETIC;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -508,13 +509,20 @@ public class DexIMethod implements IBytecodeMethod<Instruction> {
 
 	/*
 	 * (non-Javadoc)
-	 * @see com.ibm.wala.classLoader.IMethod#isSynthetic()
+	 * @see com.ibm.wala.classLoader.IMethod#isWalaSynthetic()
 	 */
 	@Override
-	public boolean isSynthetic() {
+	public boolean isWalaSynthetic() {
 		return false;
 	}
 
+    /*
+     * (non-Javadoc)
+     * @see com.ibm.wala.classLoader.IMethod#isSynthetic()
+     */
+    @Override
+    public boolean isSynthetic() { return (eMethod.getAccessFlags() & SYNTHETIC.getValue()) != 0; }
+
 	/*
 	 * (non-Javadoc)
 	 * @see com.ibm.wala.classLoader.IMember#isStatic()

com.ibm.wala.scandroid/source/org/scandroid/flow/functions/IFDSTaintFlowFunctionProvider.java

@@ -436,7 +436,7 @@ implements IFlowFunctionMap<BasicBlockInContext<E>> {
 		final SSAInvokeInstruction instruction = (SSAInvokeInstruction) src.getLastInstruction();
 		
 //		String signature = dest.getMethod().getSignature();
-//		if ( dest.getMethod().isSynthetic() ) { 
+//		if ( dest.getMethod().isWalaSynthetic() ) {
 //			System.out.println("Synthetic: "+signature);
 //		} else {
 //			System.err.println(signature);
@@ -448,7 +448,7 @@ implements IFlowFunctionMap<BasicBlockInContext<E>> {
 //			System.out.println("Call to system: "+signature);
 //		}
 		
-//		if (! dest.getMethod().isSynthetic() 
+//		if (! dest.getMethod().isWalaSynthetic()
 //		    && LoaderUtils.fromLoader(dest.getNode(), ClassLoaderReference.Primordial)) {
 //		    
 //            MyLogger.log(DEBUG,"Primordial and No Summary! (getCallFlowFunction) - " + dest.getMethod().getReference());

com.ibm.wala.scandroid/source/org/scandroid/util/CGAnalysisContext.java

@@ -195,7 +195,7 @@ public class CGAnalysisContext<E extends ISSABasicBlock> {
 		Warnings.clear();
 
 		pa = cgb.getPointerAnalysis();
-		partialGraph = GraphSlicer.prune(cg, node -> LoaderUtils.fromLoader(node, ClassLoaderReference.Application) || node.getMethod().isSynthetic());
+		partialGraph = GraphSlicer.prune(cg, node -> LoaderUtils.fromLoader(node, ClassLoaderReference.Application) || node.getMethod().isWalaSynthetic());
 		if (options.includeLibrary()) {
 			graph = (ISupergraph) ICFGSupergraph.make(cg);
 		} else {
@@ -271,7 +271,7 @@ public class CGAnalysisContext<E extends ISSABasicBlock> {
 			}
 		}
 		for (CGNode node : Iterator2Iterable.make(cg.iterator())) {
-			if (node.getMethod().isSynthetic()) {
+			if (node.getMethod().isWalaSynthetic()) {
 				SSACFG ssaCFG = node.getIR().getControlFlowGraph();
 				int totalBlocks = ssaCFG.getNumberOfNodes();
 				for (int i = 0; i < totalBlocks; i++) {

com.ibm.wala.shrike/src/com/ibm/wala/shrikeBT/Constants.java

@@ -464,6 +464,8 @@ public interface Constants {
 
   public static final short ACC_STRICT = 0x800;
 
+  public static final short ACC_SYNTHETIC = 0x1000;
+
   public static final byte CONSTANT_Utf8 = 1;
 
   public static final byte CONSTANT_Integer = 3;