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comparison src/share/vm/runtime/orderAccess.hpp @ 1930:2d26b0046e0d

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Merge.
author Thomas Wuerthinger <wuerthinger@ssw.jku.at>
date Tue, 30 Nov 2010 14:53:30 +0100
parents a6bff45449bc
children f95d63e2154a
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1484:6b7001391c97 1930:2d26b0046e0d
1 /* 1 /*
2 * Copyright 2003-2009 Sun Microsystems, Inc. All Rights Reserved. 2 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 * 4 *
5 * This code is free software; you can redistribute it and/or modify it 5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as 6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. 7 * published by the Free Software Foundation.
14 * 14 *
15 * You should have received a copy of the GNU General Public License version 15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation, 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 * 18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * CA 95054 USA or visit www.sun.com if you need additional information or 20 * or visit www.oracle.com if you need additional information or have any
21 * have any questions. 21 * questions.
22 * 22 *
23 */ 23 */
24 24
25 // Memory Access Ordering Model 25 // Memory Access Ordering Model
26 // 26 //
164 // "Program Execution". This means that all barrier implementations, 164 // "Program Execution". This means that all barrier implementations,
165 // including standalone loadload, storestore, loadstore, storeload, acquire 165 // including standalone loadload, storestore, loadstore, storeload, acquire
166 // and release must include a sequence point, usually via a volatile memory 166 // and release must include a sequence point, usually via a volatile memory
167 // access. Other ways to guarantee a sequence point are, e.g., use of 167 // access. Other ways to guarantee a sequence point are, e.g., use of
168 // indirect calls and linux's __asm__ volatile. 168 // indirect calls and linux's __asm__ volatile.
169 // Note: as of 6973570, we have replaced the originally static "dummy" field
170 // (see above) by a volatile store to the stack. All of the versions of the
171 // compilers that we currently use (SunStudio, gcc and VC++) respect the
172 // semantics of volatile here. If you build HotSpot using other
173 // compilers, you may need to verify that no compiler reordering occurs
174 // across the sequence point respresented by the volatile access.
169 // 175 //
170 // 176 //
171 // os::is_MP Considered Redundant 177 // os::is_MP Considered Redundant
172 // 178 //
173 // Callers of this interface do not need to test os::is_MP() before 179 // Callers of this interface do not need to test os::is_MP() before
295 static void release_store_fence(volatile jdouble* p, jdouble v); 301 static void release_store_fence(volatile jdouble* p, jdouble v);
296 302
297 static void release_store_ptr_fence(volatile intptr_t* p, intptr_t v); 303 static void release_store_ptr_fence(volatile intptr_t* p, intptr_t v);
298 static void release_store_ptr_fence(volatile void* p, void* v); 304 static void release_store_ptr_fence(volatile void* p, void* v);
299 305
300 // In order to force a memory access, implementations may
301 // need a volatile externally visible dummy variable.
302 static volatile intptr_t dummy;
303
304 private: 306 private:
305 // This is a helper that invokes the StubRoutines::fence_entry() 307 // This is a helper that invokes the StubRoutines::fence_entry()
306 // routine if it exists, It should only be used by platforms that 308 // routine if it exists, It should only be used by platforms that
307 // don't another way to do the inline eassembly. 309 // don't another way to do the inline eassembly.
308 static void StubRoutines_fence(); 310 static void StubRoutines_fence();