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src/share/vm/runtime/atomic.hpp

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rev 8910 : full patch for jfr
   1 /*
   2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   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
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  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,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *


  24 
  25 #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
  26 #define SHARE_VM_RUNTIME_ATOMIC_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 class Atomic : AllStatic {
  31  public:
  32   // Atomic operations on jlong types are not available on all 32-bit
  33   // platforms. If atomic ops on jlongs are defined here they must only
  34   // be used from code that verifies they are available at runtime and
  35   // can provide an alternative action if not - see supports_cx8() for
  36   // a means to test availability.
  37 
  38   // Atomically store to a location
  39   inline static void store    (jbyte    store_value, jbyte*    dest);
  40   inline static void store    (jshort   store_value, jshort*   dest);
  41   inline static void store    (jint     store_value, jint*     dest);
  42   // See comment above about using jlong atomics on 32-bit platforms
  43   inline static void store    (jlong    store_value, jlong*    dest);

  44   inline static void store_ptr(intptr_t store_value, intptr_t* dest);
  45   inline static void store_ptr(void*    store_value, void*     dest);
  46 
  47   inline static void store    (jbyte    store_value, volatile jbyte*    dest);
  48   inline static void store    (jshort   store_value, volatile jshort*   dest);
  49   inline static void store    (jint     store_value, volatile jint*     dest);
  50   // See comment above about using jlong atomics on 32-bit platforms
  51   inline static void store    (jlong    store_value, volatile jlong*    dest);
  52   inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest);
  53   inline static void store_ptr(void*    store_value, volatile void*     dest);
  54 
  55   // See comment above about using jlong atomics on 32-bit platforms
  56   inline static jlong load(volatile jlong* src);

  57 
  58   // Atomically add to a location, return updated value
  59   inline static jint     add    (jint     add_value, volatile jint*     dest);
  60   inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest);
  61   inline static void*    add_ptr(intptr_t add_value, volatile void*     dest);
  62   // See comment above about using jlong atomics on 32-bit platforms
  63          static jlong    add    (jlong    add_value, volatile jlong*    dest);

  64 
  65   // Atomically increment location
  66   inline static void inc    (volatile jint*     dest);
  67          static void inc    (volatile jshort*   dest);
  68   inline static void inc_ptr(volatile intptr_t* dest);
  69   inline static void inc_ptr(volatile void*     dest);
  70 
  71   // Atomically decrement a location
  72   inline static void dec    (volatile jint*     dest);
  73          static void dec    (volatile jshort*    dest);
  74   inline static void dec_ptr(volatile intptr_t* dest);
  75   inline static void dec_ptr(volatile void*     dest);
  76 
  77   // Performs atomic exchange of *dest with exchange_value.  Returns old prior value of *dest.
  78   inline static jint         xchg(jint         exchange_value, volatile jint*         dest);
  79          static unsigned int xchg(unsigned int exchange_value, volatile unsigned int* dest);
  80 
  81   inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest);
  82   inline static void*    xchg_ptr(void*    exchange_value, volatile void*   dest);
  83 
  84   // Performs atomic compare of *dest and compare_value, and exchanges *dest with exchange_value
  85   // if the comparison succeeded.  Returns prior value of *dest.  Guarantees a two-way memory
  86   // barrier across the cmpxchg.  I.e., it's really a 'fence_cmpxchg_acquire'.
  87          static jbyte    cmpxchg    (jbyte    exchange_value, volatile jbyte*    dest, jbyte    compare_value);
  88   inline static jint     cmpxchg    (jint     exchange_value, volatile jint*     dest, jint     compare_value);
  89   // See comment above about using jlong atomics on 32-bit platforms
  90   inline static jlong    cmpxchg    (jlong    exchange_value, volatile jlong*    dest, jlong    compare_value);

  91 
  92          static unsigned int cmpxchg(unsigned int exchange_value,
  93                                      volatile unsigned int* dest,
  94                                      unsigned int compare_value);
  95 
  96   inline static intptr_t cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value);
  97   inline static void*    cmpxchg_ptr(void*    exchange_value, volatile void*     dest, void*    compare_value);
  98 };
  99 
 100 // To use Atomic::inc(jshort* dest) and Atomic::dec(jshort* dest), the address must be specially
 101 // aligned, such that (*dest) occupies the upper 16 bits of an aligned 32-bit word. The best way to
 102 // achieve is to place your short value next to another short value, which doesn't need atomic ops.
 103 //
 104 // Example
 105 //  ATOMIC_SHORT_PAIR(
 106 //    volatile short _refcount,  // needs atomic operation
 107 //    unsigned short _length     // number of UTF8 characters in the symbol (does not need atomic op)
 108 //  );
 109 
 110 #ifdef VM_LITTLE_ENDIAN
   1 /*
   2  * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   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
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  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,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *


  24 
  25 #ifndef SHARE_VM_RUNTIME_ATOMIC_HPP
  26 #define SHARE_VM_RUNTIME_ATOMIC_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 class Atomic : AllStatic {
  31  public:
  32   // Atomic operations on jlong types are not available on all 32-bit
  33   // platforms. If atomic ops on jlongs are defined here they must only
  34   // be used from code that verifies they are available at runtime and
  35   // can provide an alternative action if not - see supports_cx8() for
  36   // a means to test availability.
  37 
  38   // Atomically store to a location
  39   inline static void store    (jbyte    store_value, jbyte*    dest);
  40   inline static void store    (jshort   store_value, jshort*   dest);
  41   inline static void store    (jint     store_value, jint*     dest);
  42   // See comment above about using jlong atomics on 32-bit platforms
  43   inline static void store    (jlong    store_value, jlong*    dest);
  44   inline static void store    (julong    store_value, julong*    dest);
  45   inline static void store_ptr(intptr_t store_value, intptr_t* dest);
  46   inline static void store_ptr(void*    store_value, void*     dest);
  47 
  48   inline static void store    (jbyte    store_value, volatile jbyte*    dest);
  49   inline static void store    (jshort   store_value, volatile jshort*   dest);
  50   inline static void store    (jint     store_value, volatile jint*     dest);
  51   // See comment above about using jlong atomics on 32-bit platforms
  52   inline static void store    (jlong    store_value, volatile jlong*    dest);
  53   inline static void store_ptr(intptr_t store_value, volatile intptr_t* dest);
  54   inline static void store_ptr(void*    store_value, volatile void*     dest);
  55 
  56   // See comment above about using jlong atomics on 32-bit platforms
  57   inline static jlong load(volatile jlong* src);
  58          static julong load(volatile julong* src);
  59 
  60   // Atomically add to a location, return updated value
  61   inline static jint     add    (jint     add_value, volatile jint*     dest);
  62   inline static intptr_t add_ptr(intptr_t add_value, volatile intptr_t* dest);
  63   inline static void*    add_ptr(intptr_t add_value, volatile void*     dest);
  64   // See comment above about using jlong atomics on 32-bit platforms
  65          static jlong    add    (jlong    add_value, volatile jlong*    dest);
  66          static julong   add    (julong   add_value, volatile julong*   dest);
  67 
  68   // Atomically increment location
  69   inline static void inc    (volatile jint*     dest);
  70          static void inc    (volatile jshort*   dest);
  71   inline static void inc_ptr(volatile intptr_t* dest);
  72   inline static void inc_ptr(volatile void*     dest);
  73 
  74   // Atomically decrement a location
  75   inline static void dec    (volatile jint*     dest);
  76          static void dec    (volatile jshort*    dest);
  77   inline static void dec_ptr(volatile intptr_t* dest);
  78   inline static void dec_ptr(volatile void*     dest);
  79 
  80   // Performs atomic exchange of *dest with exchange_value.  Returns old prior value of *dest.
  81   inline static jint         xchg(jint         exchange_value, volatile jint*         dest);
  82          static unsigned int xchg(unsigned int exchange_value, volatile unsigned int* dest);
  83 
  84   inline static intptr_t xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest);
  85   inline static void*    xchg_ptr(void*    exchange_value, volatile void*   dest);
  86 
  87   // Performs atomic compare of *dest and compare_value, and exchanges *dest with exchange_value
  88   // if the comparison succeeded.  Returns prior value of *dest.  Guarantees a two-way memory
  89   // barrier across the cmpxchg.  I.e., it's really a 'fence_cmpxchg_acquire'.
  90          static jbyte    cmpxchg    (jbyte    exchange_value, volatile jbyte*    dest, jbyte    compare_value);
  91   inline static jint     cmpxchg    (jint     exchange_value, volatile jint*     dest, jint     compare_value);
  92   // See comment above about using jlong atomics on 32-bit platforms
  93   inline static jlong    cmpxchg    (jlong    exchange_value, volatile jlong*    dest, jlong    compare_value);
  94          static julong   cmpxchg    (julong   exchange_value, volatile julong*   dest, julong   compare_value);
  95 
  96          static unsigned int cmpxchg(unsigned int exchange_value,
  97                                      volatile unsigned int* dest,
  98                                      unsigned int compare_value);
  99 
 100   inline static intptr_t cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value);
 101   inline static void*    cmpxchg_ptr(void*    exchange_value, volatile void*     dest, void*    compare_value);
 102 };
 103 
 104 // To use Atomic::inc(jshort* dest) and Atomic::dec(jshort* dest), the address must be specially
 105 // aligned, such that (*dest) occupies the upper 16 bits of an aligned 32-bit word. The best way to
 106 // achieve is to place your short value next to another short value, which doesn't need atomic ops.
 107 //
 108 // Example
 109 //  ATOMIC_SHORT_PAIR(
 110 //    volatile short _refcount,  // needs atomic operation
 111 //    unsigned short _length     // number of UTF8 characters in the symbol (does not need atomic op)
 112 //  );
 113 
 114 #ifdef VM_LITTLE_ENDIAN
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