8039043: Implicit null check is in the wrong place in C1 -UseCompressedOops
Summary: Null check is placed in a wrong place when storing a null to an object field on x64 with compressed oops off
Reviewed-by: roland, vlivanov, kvn
--- a/hotspot/src/cpu/x86/vm/c1_LIRAssembler_x86.cpp Tue Apr 01 09:05:20 2014 -0700
+++ b/hotspot/src/cpu/x86/vm/c1_LIRAssembler_x86.cpp Wed Apr 02 11:24:51 2014 -0700
@@ -799,7 +799,13 @@
if (UseCompressedOops && !wide) {
__ movl(as_Address(addr), (int32_t)NULL_WORD);
} else {
+#ifdef _LP64
+ __ xorptr(rscratch1, rscratch1);
+ null_check_here = code_offset();
+ __ movptr(as_Address(addr), rscratch1);
+#else
__ movptr(as_Address(addr), NULL_WORD);
+#endif
}
} else {
if (is_literal_address(addr)) {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/codegen/C1NullCheckOfNullStore.java Wed Apr 02 11:24:51 2014 -0700
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2014, 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 8039043
+ * @summary Null check is placed in a wrong place when storing a null to an object field on x64 with compressed oops off
+ * @run main/othervm -Xbatch -XX:+IgnoreUnrecognizedVMOptions -XX:CompileCommand=compileonly,C1NullCheckOfNullStore::test -XX:+TieredCompilation -XX:TieredStopAtLevel=1 -XX:-UseCompressedOops C1NullCheckOfNullStore
+ *
+ */
+
+public class C1NullCheckOfNullStore {
+ private static class Foo {
+ Object bar;
+ }
+ static private void test(Foo x) {
+ x.bar = null;
+ }
+ static public void main(String args[]) {
+ Foo x = new Foo();
+ for (int i = 0; i < 10000; i++) {
+ test(x);
+ }
+ boolean gotNPE = false;
+ try {
+ for (int i = 0; i < 10000; i++) {
+ test(null);
+ }
+ }
+ catch(NullPointerException e) {
+ gotNPE = true;
+ }
+ if (!gotNPE) {
+ throw new Error("Expecting a NullPointerException");
+ }
+ }
+}