8303489: Add a test to verify classes in vmStruct have unique vtables

Reviewed-by: cjplummer, sspitsyn

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/types/basic/BasicTypeDataBase.java

@@ -156,9 +156,9 @@ public class BasicTypeDataBase implements TypeDataBase {
     return VM.getVM().getOopSize();
   }
 
-  Map<Type, Address> typeToVtbl = new HashMap<>();
+  private Map<Type, Address> typeToVtbl = new HashMap<>();
 
-  private Address vtblForType(Type type) {
+  public Address vtblForType(Type type) {
     Address vtblAddr = typeToVtbl.get(type);
     if (vtblAddr == null) {
       vtblAddr = vtblAccess.getVtblForType(type);

test/hotspot/jtreg/serviceability/sa/UniqueVtableTest.java

@@ -0,0 +1,178 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ *
+ * @library /test/lib
+ * @requires vm.hasSA
+ * @modules jdk.hotspot.agent/sun.jvm.hotspot
+ *          jdk.hotspot.agent/sun.jvm.hotspot.debugger
+ *          jdk.hotspot.agent/sun.jvm.hotspot.types
+ *          jdk.hotspot.agent/sun.jvm.hotspot.types.basic
+ *
+ * @run main/othervm UniqueVtableTest
+ */
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import sun.jvm.hotspot.HotSpotAgent;
+import sun.jvm.hotspot.debugger.Address;
+import sun.jvm.hotspot.types.Type;
+import sun.jvm.hotspot.types.basic.BasicTypeDataBase;
+
+import jdk.test.lib.apps.LingeredApp;
+import jdk.test.lib.SA.SATestUtils;
+
+
+public class UniqueVtableTest {
+
+    private HotSpotAgent agent;
+
+    public UniqueVtableTest() {
+    }
+
+    private static String type2String(Type t) {
+        return t + " (extends " + t.getSuperclass() + ")";
+    }
+
+    private static void log(Object o) {
+        System.out.println(o);
+    }
+
+    private void attach(long pid) throws Throwable {
+        agent = new HotSpotAgent();
+        log("Attaching to process ID " + pid + "...");
+        agent.attach((int) pid);
+        log("Attached successfully.");
+    }
+
+    private void detach() {
+        if (agent != null) {
+            agent.detach();
+        }
+    }
+
+    private void runTest() throws Throwable {
+        Map<Address, List<Type>> vtableToTypesMap = new HashMap<>();
+        Iterator<Type> it = agent.getTypeDataBase().getTypes();
+        int dupsFound = 0;
+        // TypeDataBase knows nothing about vtables,
+        // but actually agent.getTypeDataBase() returns HotSpotTypeDataBase (extends BasicTypeDataBase)
+        // and BasicTypeDataBase has a method to get vtable for Types.
+        BasicTypeDataBase typeDB = (BasicTypeDataBase)(agent.getTypeDataBase());
+        int total = 0;
+        int vm_classes_with_vtable = 0;
+        int vm_classes_without_vtable = 0;
+        while (it.hasNext()) {
+            total++;
+            Type t = it.next();
+            Address vtable = typeDB.vtblForType(t);
+            if (vtable != null) {
+                vm_classes_with_vtable++;
+                List<Type> typeList = vtableToTypesMap.get(vtable);
+                if (typeList == null) {
+                    vtableToTypesMap.put(vtable, new ArrayList<>(List.of(t)));
+                } else {
+                    // duplicate found
+                    dupsFound++;
+                    typeList.add(t);
+                }
+            }
+
+            // IntegerType/StringType/JavaPrimitiveType/OopType/PointerType types
+            // are expected to have no vtable.
+            // Log classes which might need vtable.
+            if (vtable == null
+                    && !t.isCIntegerType()
+                    && !t.isCStringType()
+                    && !t.isJavaPrimitiveType()
+                    && !t.isOopType()
+                    && !t.isPointerType()) {
+                vm_classes_without_vtable++;
+                log("vtable is null for " + type2String(t));
+            }
+        }
+        log("total: " + total
+            + ", vm_classes_with_vtable: " + vm_classes_with_vtable
+            + ", vm_classes_without_vtable: " + vm_classes_without_vtable);
+        if (dupsFound > 0) {
+            vtableToTypesMap.forEach((vtable, list) -> {
+                if (list.size() > 1) {
+                    log("Duplicate vtable: " + vtable + ": ");
+                    list.forEach(t -> log("  - " + type2String(t)));
+                }
+            });
+            throw new RuntimeException("Duplicate vtable(s) found: " + dupsFound);
+        }
+    }
+
+    private void run() throws Throwable {
+        Throwable reasonToFail = null;
+        LingeredApp app = null;
+        try {
+            app = LingeredApp.startApp();
+            attach(app.getPid());
+            runTest();
+        } catch (Throwable ex) {
+            reasonToFail = ex;
+        } finally {
+            try {
+                detach();
+            } catch (Exception ex) {
+                log("detach error:");
+                ex.printStackTrace(System.out);
+                // do not override original error
+                if (reasonToFail != null) {
+                    reasonToFail = ex;
+                }
+            }
+            try {
+                LingeredApp.stopApp(app);
+            } catch (Exception ex) {
+                log("LingeredApp.stopApp error:");
+                ex.printStackTrace(System.out);
+                // do not override original error
+                if (reasonToFail != null) {
+                    reasonToFail = ex;
+                }
+            }
+        }
+        if (reasonToFail != null) {
+            throw reasonToFail;
+        }
+    }
+
+    public static void main(String... args) throws Throwable {
+        SATestUtils.skipIfCannotAttach(); // throws SkippedException if attach not expected to work.
+
+        UniqueVtableTest test = new UniqueVtableTest();
+
+        test.run();
+    }
+
+ }