8226798: JVM crash in klassItable::initialize_itable_for_interface(int, InstanceKlass*, bool, Thread*)
Summary: When calculating vtable size at class load time, do not look for miranda method if matching package private method is found in a super class.
Reviewed-by: acorn, lfoltan
--- a/src/hotspot/share/oops/klassVtable.cpp Thu Jul 04 17:31:03 2019 +0200
+++ b/src/hotspot/share/oops/klassVtable.cpp Thu Jul 11 09:26:04 2019 -0400
@@ -638,6 +638,7 @@
Method* super_method = NULL;
InstanceKlass *holder = NULL;
Method* recheck_method = NULL;
+ bool found_pkg_prvt_method = false;
while (k != NULL) {
// lookup through the hierarchy for a method with matching name and sign.
super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
@@ -659,6 +660,16 @@
return false;
// else keep looking for transitive overrides
}
+ // If we get here then one of the super classes has a package private method
+ // that will not get overridden because it is in a different package. But,
+ // that package private method does "override" any matching methods in super
+ // interfaces, so there will be no miranda vtable entry created. So, set flag
+ // to TRUE for use below, in case there are no methods in super classes that
+ // this target method overrides.
+ assert(super_method->is_package_private(), "super_method must be package private");
+ assert(!superk->is_same_class_package(classloader(), classname),
+ "Must be different packages");
+ found_pkg_prvt_method = true;
}
// Start with lookup result and continue to search up, for versions supporting transitive override
@@ -669,6 +680,15 @@
}
}
+ // If found_pkg_prvt_method is set, then the ONLY matching method in the
+ // superclasses is package private in another package. That matching method will
+ // prevent a miranda vtable entry from being created. Because the target method can not
+ // override the package private method in another package, then it needs to be the root
+ // for its own vtable entry.
+ if (found_pkg_prvt_method) {
+ return true;
+ }
+
// if the target method is public or protected it may have a matching
// miranda method in the super, whose entry it should re-use.
// Actually, to handle cases that javac would not generate, we need
@@ -676,7 +696,7 @@
const InstanceKlass *sk = InstanceKlass::cast(super);
if (sk->has_miranda_methods()) {
if (sk->lookup_method_in_all_interfaces(name, signature, Klass::find_defaults) != NULL) {
- return false; // found a matching miranda; we do not need a new entry
+ return false; // found a matching miranda; we do not need a new entry
}
}
return true; // found no match; we need a new entry
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/runtime/VtableTests/VTableTest.java Thu Jul 11 09:26:04 2019 -0400
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2019, 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
+ * @bug 8226798
+ * @summary Check that the vTable for class C gets set up without causing
+ * an assertion failure.
+ * @compile pkg/A.java
+ * @run main VTableTest
+ */
+
+public class VTableTest {
+
+ interface Intf {
+ public default void m() { }
+ public default void unusedButNeededToReproduceIssue() { }
+ }
+
+ static class B extends pkg.A implements Intf {
+ }
+
+ static class C extends B {
+ public void m() { System.out.println("In C.m()"); }
+ }
+
+ public static void main(String[] args) {
+ new C().m();
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/runtime/VtableTests/pkg/A.java Thu Jul 11 09:26:04 2019 -0400
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+
+package pkg;
+
+public class A {
+ void m() { }
+}