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83ffe9cd | 1 | /* Copyright (C) 2005-2023 Free Software Foundation, Inc. |
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2 | Contributed by Richard Henderson <rth@redhat.com>. |
3 | ||
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4 | This file is part of the GNU Offloading and Multi Processing Library |
5 | (libgomp). | |
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6 | |
7 | Libgomp is free software; you can redistribute it and/or modify it | |
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8 | under the terms of the GNU General Public License as published by |
9 | the Free Software Foundation; either version 3, or (at your option) | |
10 | any later version. | |
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11 | |
12 | Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
748086b7 | 14 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
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15 | more details. |
16 | ||
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17 | Under Section 7 of GPL version 3, you are granted additional |
18 | permissions described in the GCC Runtime Library Exception, version | |
19 | 3.1, as published by the Free Software Foundation. | |
20 | ||
21 | You should have received a copy of the GNU General Public License and | |
22 | a copy of the GCC Runtime Library Exception along with this program; | |
23 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
24 | <http://www.gnu.org/licenses/>. */ | |
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25 | |
26 | /* This file handles the CRITICAL construct. */ | |
27 | ||
28 | #include "libgomp.h" | |
29 | #include <stdlib.h> | |
30 | ||
31 | ||
32 | static gomp_mutex_t default_lock; | |
33 | ||
34 | void | |
35 | GOMP_critical_start (void) | |
36 | { | |
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37 | /* There is an implicit flush on entry to a critical region. */ |
38 | __atomic_thread_fence (MEMMODEL_RELEASE); | |
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39 | gomp_mutex_lock (&default_lock); |
40 | } | |
41 | ||
42 | void | |
43 | GOMP_critical_end (void) | |
44 | { | |
45 | gomp_mutex_unlock (&default_lock); | |
46 | } | |
47 | ||
48 | #ifndef HAVE_SYNC_BUILTINS | |
49 | static gomp_mutex_t create_lock_lock; | |
50 | #endif | |
51 | ||
52 | void | |
53 | GOMP_critical_name_start (void **pptr) | |
54 | { | |
55 | gomp_mutex_t *plock; | |
56 | ||
57 | /* If a mutex fits within the space for a pointer, and is zero initialized, | |
58 | then use the pointer space directly. */ | |
59 | if (GOMP_MUTEX_INIT_0 | |
60 | && sizeof (gomp_mutex_t) <= sizeof (void *) | |
61 | && __alignof (gomp_mutex_t) <= sizeof (void *)) | |
62 | plock = (gomp_mutex_t *)pptr; | |
63 | ||
64 | /* Otherwise we have to be prepared to malloc storage. */ | |
65 | else | |
66 | { | |
67 | plock = *pptr; | |
68 | ||
69 | if (plock == NULL) | |
70 | { | |
71 | #ifdef HAVE_SYNC_BUILTINS | |
72 | gomp_mutex_t *nlock = gomp_malloc (sizeof (gomp_mutex_t)); | |
73 | gomp_mutex_init (nlock); | |
74 | ||
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75 | plock = __sync_val_compare_and_swap (pptr, NULL, nlock); |
76 | if (plock != NULL) | |
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77 | { |
78 | gomp_mutex_destroy (nlock); | |
79 | free (nlock); | |
80 | } | |
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81 | else |
82 | plock = nlock; | |
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83 | #else |
84 | gomp_mutex_lock (&create_lock_lock); | |
85 | plock = *pptr; | |
86 | if (plock == NULL) | |
87 | { | |
88 | plock = gomp_malloc (sizeof (gomp_mutex_t)); | |
89 | gomp_mutex_init (plock); | |
90 | __sync_synchronize (); | |
91 | *pptr = plock; | |
92 | } | |
93 | gomp_mutex_unlock (&create_lock_lock); | |
94 | #endif | |
95 | } | |
96 | } | |
97 | ||
98 | gomp_mutex_lock (plock); | |
99 | } | |
100 | ||
101 | void | |
102 | GOMP_critical_name_end (void **pptr) | |
103 | { | |
104 | gomp_mutex_t *plock; | |
105 | ||
106 | /* If a mutex fits within the space for a pointer, and is zero initialized, | |
107 | then use the pointer space directly. */ | |
108 | if (GOMP_MUTEX_INIT_0 | |
109 | && sizeof (gomp_mutex_t) <= sizeof (void *) | |
110 | && __alignof (gomp_mutex_t) <= sizeof (void *)) | |
111 | plock = (gomp_mutex_t *)pptr; | |
112 | else | |
113 | plock = *pptr; | |
114 | ||
115 | gomp_mutex_unlock (plock); | |
116 | } | |
117 | ||
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118 | #if !GOMP_MUTEX_INIT_0 |
119 | static void __attribute__((constructor)) | |
120 | initialize_critical (void) | |
121 | { | |
122 | gomp_mutex_init (&default_lock); | |
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123 | #ifndef HAVE_SYNC_BUILTINS |
124 | gomp_mutex_init (&create_lock_lock); | |
125 | #endif | |
126 | } | |
127 | #endif |