# HG changeset patch

# User shade

# Date 1488979372 -3600

#      Wed Mar 08 14:22:52 2017 +0100

# Node ID 654b7fcb4932d48063f5f1fba0c8994db5e02976

# Parent  1faf7c17089922f6f72b580253725f2ecb6ba2f8

8175887, PR3415: C1 value numbering handling of Unsafe.get*Volatile is incorrect

Reviewed-by: vlivanov

diff --git a/src/share/vm/c1/c1_ValueMap.hpp b/src/share/vm/c1/c1_ValueMap.hpp

--- openjdk/hotspot/src/share/vm/c1/c1_ValueMap.hpp

+++ openjdk/hotspot/src/share/vm/c1/c1_ValueMap.hpp

@@ -158,6 +158,12 @@

   void do_UnsafePutRaw   (UnsafePutRaw*    x) { kill_memory(); }

   void do_UnsafePutObject(UnsafePutObject* x) { kill_memory(); }

   void do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) { kill_memory(); }

+  void do_UnsafeGetRaw   (UnsafeGetRaw*    x) { /* nothing to do */ }

+  void do_UnsafeGetObject(UnsafeGetObject* x) {

+    if (x->is_volatile()) { // the JMM requires this

+      kill_memory();

+    }

+  }

   void do_Intrinsic      (Intrinsic*       x) { if (!x->preserves_state()) kill_memory(); }

   void do_Phi            (Phi*             x) { /* nothing to do */ }

@@ -198,8 +204,6 @@

   void do_OsrEntry       (OsrEntry*        x) { /* nothing to do */ }

   void do_ExceptionObject(ExceptionObject* x) { /* nothing to do */ }

   void do_RoundFP        (RoundFP*         x) { /* nothing to do */ }

-  void do_UnsafeGetRaw   (UnsafeGetRaw*    x) { /* nothing to do */ }

-  void do_UnsafeGetObject(UnsafeGetObject* x) { /* nothing to do */ }

   void do_UnsafePrefetchRead (UnsafePrefetchRead*  x) { /* nothing to do */ }

   void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) { /* nothing to do */ }

   void do_ProfileCall    (ProfileCall*     x) { /* nothing to do */ }

diff --git a/test/compiler/c1/UnsafeVolatileGuardTest.java b/test/compiler/c1/UnsafeVolatileGuardTest.java

new file mode 100644

--- /dev/null

+++ openjdk/hotspot/test/compiler/c1/UnsafeVolatileGuardTest.java

@@ -0,0 +1,72 @@

+/*

+ * Copyright (c) 2017, Red Hat Inc. 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.

+ */

+

+import java.lang.reflect.Field;

+

+/**

+ * @test

+ * @bug 8175887

+ * @summary C1 value numbering handling of Unsafe.get*Volatile is incorrect

+ * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TieredStopAtLevel=1 UnsafeVolatileGuardTest

+ */

+public class UnsafeVolatileGuardTest {

+    volatile static private int a;

+    static private int b;

+

+    static final sun.misc.Unsafe UNSAFE;

+

+    static final Object BASE;

+    static final long OFFSET;

+

+    static {

+        try {

+            Field uf = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");

+            uf.setAccessible(true);

+            UNSAFE = (sun.misc.Unsafe)uf.get(null);

+

+            Field f = UnsafeVolatileGuardTest.class.getDeclaredField("a");

+            BASE = UNSAFE.staticFieldBase(f);

+            OFFSET = UNSAFE.staticFieldOffset(f);

+        } catch (Exception e) {

+            throw new RuntimeException(e);

+        }

+    }

+

+    static void test() {

+        int tt = b; // makes the JVM CSE the value of b

+

+        while (UNSAFE.getIntVolatile(BASE, OFFSET) == 0) {} // burn

+        if (b == 0) {

+            System.err.println("wrong value of b");

+            System.exit(1); // fail hard to report the error

+        }

+    }

+

+    public static void main(String [] args) throws Exception {

+        for (int i = 0; i < 10; i++) {

+            new Thread(UnsafeVolatileGuardTest::test).start();

+        }

+        b = 1;

+        a = 1;

+    }

+}

diff --git a/test/compiler/c1/VolatileGuardTest.java b/test/compiler/c1/VolatileGuardTest.java

new file mode 100644

--- /dev/null

+++ openjdk/hotspot/test/compiler/c1/VolatileGuardTest.java

@@ -0,0 +1,52 @@

+/*

+ * Copyright (c) 2017, Red Hat Inc. 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 8175887

+ * @summary C1 doesn't respect the JMM with volatile field loads

+ *

+ * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:TieredStopAtLevel=1 VolatileGuardTest

+ */

+public class VolatileGuardTest {

+    volatile static private int a;

+    static private int b;

+

+    static void test() {

+        int tt = b; // makes the JVM CSE the value of b

+

+        while (a == 0) {} // burn

+        if (b == 0) {

+            System.err.println("wrong value of b");

+            System.exit(1); // fail hard to report the error

+        }

+    }

+

+    public static void main(String [] args) throws Exception {

+        for (int i = 0; i < 10; i++) {

+            new Thread(VolatileGuardTest::test).start();

+        }

+        b = 1;

+        a = 1;

+    }

+}