8268192: LambdaMetafactory with invokespecial causes VerificationError

Reviewed-by: psandoz, mchung

Author: Dan Smith

src/java.base/share/classes/java/lang/invoke/AbstractValidatingLambdaMetafactory.java

@@ -154,14 +154,10 @@
                 this.implClass = implInfo.getDeclaringClass();
                 this.implIsInstanceMethod = true;
 
-                // Classes compiled prior to dynamic nestmate support invokes a private instance
-                // method with REF_invokeSpecial.
-                //
-                // invokespecial should only be used to invoke private nestmate constructors.
-                // The lambda proxy class will be defined as a nestmate of targetClass.
-                // If the method to be invoked is an instance method of targetClass, then
-                // convert to use invokevirtual or invokeinterface.
-                if (targetClass == implClass && !implInfo.getName().equals("<init>")) {
+                // Classes compiled prior to dynamic nestmate support invoke a private instance
+                // method with REF_invokeSpecial. Newer classes use REF_invokeVirtual or
+                // REF_invokeInterface, and we can use that instruction in the lambda class.
+                if (targetClass == implClass) {
                     this.implKind = implClass.isInterface() ? REF_invokeInterface : REF_invokeVirtual;
                 } else {
                     this.implKind = REF_invokeSpecial;

src/java.base/share/classes/java/lang/invoke/InnerClassLambdaMetafactory.java

@@ -180,8 +180,15 @@ public InnerClassLambdaMetafactory(MethodHandles.Lookup caller,
         implMethodDesc = implInfo.getMethodType().toMethodDescriptorString();
         constructorType = factoryType.changeReturnType(Void.TYPE);
         lambdaClassName = lambdaClassName(targetClass);
-        useImplMethodHandle = !Modifier.isPublic(implInfo.getModifiers()) &&
-                              !VerifyAccess.isSamePackage(implClass, implInfo.getDeclaringClass());
+        // If the target class invokes a protected method inherited from a
+        // superclass in a different package, or does 'invokespecial', the
+        // lambda class has no access to the resolved method. Instead, we need
+        // to pass the live implementation method handle to the proxy class
+        // to invoke directly. (javac prefers to avoid this situation by
+        // generating bridges in the target class)
+        useImplMethodHandle = (Modifier.isProtected(implInfo.getModifiers()) &&
+                               !VerifyAccess.isSamePackage(implClass, implInfo.getDeclaringClass())) ||
+                               implKind == H_INVOKESPECIAL;
         cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
         int parameterCount = factoryType.parameterCount();
         if (parameterCount > 0) {
@@ -394,13 +401,6 @@ public Void run() {
             // this class is linked at the indy callsite; so define a hidden nestmate
             Lookup lookup;
             if (useImplMethodHandle) {
-                // If the target class invokes a method reference this::m which is
-                // resolved to a protected method inherited from a superclass in a different
-                // package, the target class does not have a bridge and this method reference
-                // has been changed from public to protected after the target class was compiled.
-                // This lambda proxy class has no access to the resolved method.
-                // So this workaround by passing the live implementation method handle
-                // to the proxy class to invoke directly.
                 lookup = caller.defineHiddenClassWithClassData(classBytes, implementation, !disableEagerInitialization,
                                                                NESTMATE, STRONG);
             } else {

test/jdk/java/lang/invoke/lambda/MetafactoryArgValidationTest.java

@@ -153,9 +153,8 @@ public static void testLCE() {
         amfSucceed(C.lookup, "m", toI, arr(cToVoid, C.invokeVirtualMH(), cToVoid, flagSer));
         mfSucceed(C.lookup, "m", toI, toVoid, C.invokeStaticMH(), toVoid);
         amfSucceed(C.lookup, "m", toI, arr(toVoid, C.invokeStaticMH(), toVoid, flagSer));
-        // 8268192: these fail with a VerifyError, need to fix
-        //mfSucceed(C.lookup, "m", toI, cToString, C.invokeSpecialMH(), cToString);
-        //amfSucceed(C.lookup, "m", toI, arr(cToString, C.invokeSpecialMH(), cToString, flagSer));
+        mfSucceed(C.lookup, "m", toI, cToString, C.invokeSpecialMH(), cToString);
+        amfSucceed(C.lookup, "m", toI, arr(cToString, C.invokeSpecialMH(), cToString, flagSer));
         mfSucceed(C.lookup, "m", toI, toC, C.newInvokeSpecialMH(), toC);
         amfSucceed(C.lookup, "m", toI, arr(toC, C.newInvokeSpecialMH(), toC, flagSer));
         mfSucceed(C.lookup, "m", toI, cToVoid, C.invokeInterfaceMH(), cToVoid);