Improve CHABuilder precision via resolving callees using the type of the receiver variable (#197)

Author: jjppp

src/main/java/pascal/taie/analysis/graph/callgraph/CHABuilder.java

@@ -25,7 +25,9 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import pascal.taie.World;
+import pascal.taie.analysis.pta.plugin.util.InvokeUtils;
 import pascal.taie.config.ConfigException;
+import pascal.taie.ir.exp.Var;
 import pascal.taie.ir.proginfo.MemberRef;
 import pascal.taie.ir.proginfo.MethodRef;
 import pascal.taie.ir.stmt.Invoke;
@@ -34,6 +36,8 @@
 import pascal.taie.language.classes.JClass;
 import pascal.taie.language.classes.JMethod;
 import pascal.taie.language.classes.Subsignature;
+import pascal.taie.language.type.ClassType;
+import pascal.taie.language.type.NullType;
 import pascal.taie.util.AnalysisException;
 import pascal.taie.util.collection.Maps;
 import pascal.taie.util.collection.TwoKeyMap;
@@ -151,7 +155,15 @@ private Set<JMethod> resolveCalleesOf(Invoke callSite) {
                 if (ignoreObjectMethods && isObjectMethod(methodRef)) {
                     yield Set.of();
                 }
-                JClass cls = methodRef.getDeclaringClass();
+                Var base = InvokeUtils.getVar(callSite, InvokeUtils.BASE);
+                JClass cls;
+                if (base.getType() instanceof ClassType classType) {
+                    cls = classType.getJClass();
+                } else if (base.getType() instanceof NullType) {
+                    yield Set.of();
+                } else {
+                    cls = methodRef.getDeclaringClass();
+                }
                 Set<JMethod> callees = resolveTable.get(cls, methodRef);
                 if (callees == null) {
                     callees = hierarchy.getAllSubclassesOf(cls)

src/test/java/pascal/taie/analysis/graph/callgraph/cha/CHATest.java

@@ -22,9 +22,21 @@
 
 package pascal.taie.analysis.graph.callgraph.cha;
 
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
+import pascal.taie.Main;
+import pascal.taie.World;
 import pascal.taie.analysis.Tests;
+import pascal.taie.analysis.graph.callgraph.CallGraph;
+import pascal.taie.analysis.graph.callgraph.CallGraphBuilder;
+import pascal.taie.ir.stmt.Invoke;
+import pascal.taie.language.classes.JMethod;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
 public class CHATest {
 
@@ -45,4 +57,18 @@ void testFull(String mainClass) {
         test(mainClass);
     }
 
+    @Test
+    void testArray() {
+        Main.main("-pp",
+                "-cp", CLASS_PATH,
+                "-m", "Array",
+                "-a", "cg=algorithm:cha-full");
+        CallGraph<Invoke, JMethod> callGraph = World.get().getResult(CallGraphBuilder.ID);
+        JMethod main = World.get().getMainMethod();
+        List<Invoke> invokes = main.getIR().invokes(false).toList();
+        assertEquals(2, invokes.size());
+        assertFalse(callGraph.getCalleesOf(invokes.get(0)).isEmpty());
+        assertFalse(callGraph.getCalleesOf(invokes.get(1)).isEmpty());
+    }
+
 }

src/test/resources/cha/Array.java

@@ -0,0 +1,7 @@
+public class Array {
+    public static void main(String[] args) {
+        Object[] array = new Object[114];
+        String s = array.toString();
+        int hashCode = array.hashCode();
+    }
+}