8139758: [REDO] Elide more final field's write memory barrier with escape analysis result
authorhshi
Mon, 16 Nov 2015 16:14:15 +0100
changeset 34183 8b683720a3e4
parent 34181 663d662fdff0
child 34184 9c242c118ed0
8139758: [REDO] Elide more final field's write memory barrier with escape analysis result Summary: membar for all final field initializations eliminated if possible Reviewed-by: roland, vlivanov
hotspot/src/share/vm/opto/parse1.cpp
hotspot/src/share/vm/opto/parse3.cpp
hotspot/test/compiler/stable/TestStableMemoryBarrier.java
--- a/hotspot/src/share/vm/opto/parse1.cpp	Mon Nov 16 11:58:31 2015 +0000
+++ b/hotspot/src/share/vm/opto/parse1.cpp	Mon Nov 16 16:14:15 2015 +0100
@@ -964,11 +964,12 @@
     }
   }
 
-  // Any method can write a @Stable field; insert memory barriers after
-  // those also. If there is a predecessor allocation node, bind the
-  // barrier there.
+  // Any method can write a @Stable field; insert memory barriers
+  // after those also. Can't bind predecessor allocation node (if any)
+  // with barrier because allocation doesn't always dominate
+  // MemBarRelease.
   if (wrote_stable()) {
-    _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final());
+    _exits.insert_mem_bar(Op_MemBarRelease);
     if (PrintOpto && (Verbose || WizardMode)) {
       method()->print_name();
       tty->print_cr(" writes @Stable and needs a memory barrier");
--- a/hotspot/src/share/vm/opto/parse3.cpp	Mon Nov 16 11:58:31 2015 +0000
+++ b/hotspot/src/share/vm/opto/parse3.cpp	Mon Nov 16 16:14:15 2015 +0100
@@ -311,9 +311,8 @@
 
     // Preserve allocation ptr to create precedent edge to it in membar
     // generated on exit from constructor.
-    if (C->eliminate_boxing() &&
-        adr_type->isa_oopptr() && adr_type->is_oopptr()->is_ptr_to_boxed_value() &&
-        AllocateNode::Ideal_allocation(obj, &_gvn) != NULL) {
+    // Can't bind stable with its allocation, only record allocation for final field.
+    if (field->is_final() && AllocateNode::Ideal_allocation(obj, &_gvn) != NULL) {
       set_alloc_with_final(obj);
     }
   }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/stable/TestStableMemoryBarrier.java	Mon Nov 16 16:14:15 2015 +0100
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2015, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 TestStableMemoryBarrier
+ * @bug 8139758
+ * @summary tests memory barrier correctly inserted for stable fields
+ * @library /testlibrary /../../test/lib
+ *
+ * @run main/bootclasspath -Xcomp -XX:CompileOnly=::testCompile
+ *                   java.lang.invoke.TestStableMemoryBarrier
+ *
+ * @author hui.shi@linaro.org
+ */
+package java.lang.invoke;
+
+import java.lang.reflect.InvocationTargetException;
+
+public class TestStableMemoryBarrier {
+
+    public static void main(String[] args) throws Exception {
+        run(NotDominate.class);
+
+    }
+
+    /* ====================================================
+     * Stable field initialized in method, but its allocation
+     * doesn't dominate MemBar Release at the end of method.
+     */
+
+    static class NotDominate{
+        public @Stable int v;
+        public static int[] array = new int[100];
+        public static NotDominate testCompile(int n) {
+           if ((n % 2) == 0) return null;
+           // add a loop here, trigger PhaseIdealLoop::verify_dominance
+           for (int i = 0; i < 100; i++) {
+              array[i] = n;
+           }
+           NotDominate nm = new NotDominate();
+           nm.v = n;
+           return nm;
+        }
+
+        public static void test() throws Exception {
+           for (int i = 0; i < 1000000; i++)
+               testCompile(i);
+        }
+    }
+
+    public static void run(Class<?> test) {
+        Throwable ex = null;
+        System.out.print(test.getName()+": ");
+        try {
+            test.getMethod("test").invoke(null);
+        } catch (InvocationTargetException e) {
+            ex = e.getCause();
+        } catch (Throwable e) {
+            ex = e;
+        } finally {
+            if (ex == null) {
+                System.out.println("PASSED");
+            } else {
+                System.out.println("FAILED");
+                ex.printStackTrace(System.out);
+            }
+        }
+    }
+}