1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/runtime/atomic.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,120 @@
1.4 +/*
1.5 + * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
1.29 +#define SHARE_VM_RUNTIME_ATOMIC_HPP
1.30 +
1.31 +#include "memory/allocation.hpp"
1.32 +
1.33 +class Atomic : AllStatic {
1.34 + public:
1.35 + // Atomic operations on jlong types are not available on all 32-bit
1.36 + // platforms. If atomic ops on jlongs are defined here they must only
1.37 + // be used from code that verifies they are available at runtime and
1.38 + // can provide an alternative action if not - see supports_cx8() for
1.39 + // a means to test availability.
1.40 +
1.41 + // Atomically store to a location
1.42 + inline static void store (jbyte store_value, jbyte* dest);
1.43 + inline static void store (jshort store_value, jshort* dest);
1.44 + inline static void store (jint store_value, jint* dest);
1.45 + // See comment above about using jlong atomics on 32-bit platforms
1.46 + inline static void store (jlong store_value, jlong* dest);
1.47 + inline static void store_ptr(intptr_t store_value, intptr_t* dest);
1.48 + inline static void store_ptr(void* store_value, void* dest);
1.49 +
1.50 + inline static void store (jbyte store_value, volatile jbyte* dest);
1.51 + inline static void store (jshort store_value, volatile jshort* dest);
1.52 + inline static void store (jint store_value, volatile jint* dest);
1.53 + // See comment above about using jlong atomics on 32-bit platforms
1.54 + inline static void store (jlong store_value, volatile jlong* dest);
1.55 + inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest);
1.56 + inline static void store_ptr(void* store_value, volatile void* dest);
1.57 +
1.58 + // See comment above about using jlong atomics on 32-bit platforms
1.59 + inline static jlong load(volatile jlong* src);
1.60 +
1.61 + // Atomically add to a location, return updated value
1.62 + inline static jint add (jint add_value, volatile jint* dest);
1.63 + inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest);
1.64 + inline static void* add_ptr(intptr_t add_value, volatile void* dest);
1.65 + // See comment above about using jlong atomics on 32-bit platforms
1.66 + static jlong add (jlong add_value, volatile jlong* dest);
1.67 +
1.68 + // Atomically increment location
1.69 + inline static void inc (volatile jint* dest);
1.70 + static void inc (volatile jshort* dest);
1.71 + inline static void inc_ptr(volatile intptr_t* dest);
1.72 + inline static void inc_ptr(volatile void* dest);
1.73 +
1.74 + // Atomically decrement a location
1.75 + inline static void dec (volatile jint* dest);
1.76 + static void dec (volatile jshort* dest);
1.77 + inline static void dec_ptr(volatile intptr_t* dest);
1.78 + inline static void dec_ptr(volatile void* dest);
1.79 +
1.80 + // Performs atomic exchange of *dest with exchange_value. Returns old prior value of *dest.
1.81 + inline static jint xchg(jint exchange_value, volatile jint* dest);
1.82 + static unsigned int xchg(unsigned int exchange_value, volatile unsigned int* dest);
1.83 +
1.84 + inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest);
1.85 + inline static void* xchg_ptr(void* exchange_value, volatile void* dest);
1.86 +
1.87 + // Performs atomic compare of *dest and compare_value, and exchanges *dest with exchange_value
1.88 + // if the comparison succeeded. Returns prior value of *dest. Guarantees a two-way memory
1.89 + // barrier across the cmpxchg. I.e., it's really a 'fence_cmpxchg_acquire'.
1.90 + static jbyte cmpxchg (jbyte exchange_value, volatile jbyte* dest, jbyte compare_value);
1.91 + inline static jint cmpxchg (jint exchange_value, volatile jint* dest, jint compare_value);
1.92 + // See comment above about using jlong atomics on 32-bit platforms
1.93 + inline static jlong cmpxchg (jlong exchange_value, volatile jlong* dest, jlong compare_value);
1.94 +
1.95 + static unsigned int cmpxchg(unsigned int exchange_value,
1.96 + volatile unsigned int* dest,
1.97 + unsigned int compare_value);
1.98 +
1.99 + inline static intptr_t cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value);
1.100 + inline static void* cmpxchg_ptr(void* exchange_value, volatile void* dest, void* compare_value);
1.101 +};
1.102 +
1.103 +// To use Atomic::inc(jshort* dest) and Atomic::dec(jshort* dest), the address must be specially
1.104 +// aligned, such that (*dest) occupies the upper 16 bits of an aligned 32-bit word. The best way to
1.105 +// achieve is to place your short value next to another short value, which doesn't need atomic ops.
1.106 +//
1.107 +// Example
1.108 +// ATOMIC_SHORT_PAIR(
1.109 +// volatile short _refcount, // needs atomic operation
1.110 +// unsigned short _length // number of UTF8 characters in the symbol (does not need atomic op)
1.111 +// );
1.112 +
1.113 +#ifdef VM_LITTLE_ENDIAN
1.114 +#define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \
1.115 + non_atomic_decl; \
1.116 + atomic_decl
1.117 +#else
1.118 +#define ATOMIC_SHORT_PAIR(atomic_decl, non_atomic_decl) \
1.119 + atomic_decl ; \
1.120 + non_atomic_decl
1.121 +#endif
1.122 +
1.123 +#endif // SHARE_VM_RUNTIME_ATOMIC_HPP
