Branch data Line data Source code
1 : : /* Memory handling for libdw.
2 : : Copyright (C) 2003, 2004, 2006 Red Hat, Inc.
3 : : This file is part of elfutils.
4 : : Written by Ulrich Drepper <drepper@redhat.com>, 2003.
5 : :
6 : : This file is free software; you can redistribute it and/or modify
7 : : it under the terms of either
8 : :
9 : : * the GNU Lesser General Public License as published by the Free
10 : : Software Foundation; either version 3 of the License, or (at
11 : : your option) any later version
12 : :
13 : : or
14 : :
15 : : * the GNU General Public License as published by the Free
16 : : Software Foundation; either version 2 of the License, or (at
17 : : your option) any later version
18 : :
19 : : or both in parallel, as here.
20 : :
21 : : elfutils is distributed in the hope that it will be useful, but
22 : : WITHOUT ANY WARRANTY; without even the implied warranty of
23 : : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 : : General Public License for more details.
25 : :
26 : : You should have received copies of the GNU General Public License and
27 : : the GNU Lesser General Public License along with this program. If
28 : : not, see <http://www.gnu.org/licenses/>. */
29 : :
30 : : #ifdef HAVE_CONFIG_H
31 : : # include <config.h>
32 : : #endif
33 : :
34 : : #include <errno.h>
35 : : #include <stdlib.h>
36 : : #include "libdwP.h"
37 : : #include "system.h"
38 : : #include <stdatomic.h>
39 : : #if USE_VG_ANNOTATIONS == 1
40 : : #include <helgrind.h>
41 : : #else
42 : : #define ANNOTATE_HAPPENS_BEFORE(X)
43 : : #define ANNOTATE_HAPPENS_AFTER(X)
44 : : #endif
45 : :
46 : : #define THREAD_ID_UNSET ((size_t) -1)
47 : : static __thread size_t thread_id = THREAD_ID_UNSET;
48 : : static atomic_size_t next_id = 0;
49 : :
50 : : struct libdw_memblock *
51 : 6100824 : __libdw_alloc_tail (Dwarf *dbg)
52 : : {
53 [ + + ]: 6100824 : if (thread_id == THREAD_ID_UNSET)
54 : 1136 : thread_id = atomic_fetch_add (&next_id, 1);
55 : :
56 : 6100824 : pthread_rwlock_rdlock (&dbg->mem_rwl);
57 [ + + ]: 6100824 : if (thread_id >= dbg->mem_stacks)
58 : : {
59 : 1780 : pthread_rwlock_unlock (&dbg->mem_rwl);
60 : 1780 : pthread_rwlock_wrlock (&dbg->mem_rwl);
61 : :
62 : : /* Another thread may have already reallocated. In theory using an
63 : : atomic would be faster, but given that this only happens once per
64 : : thread per Dwarf, some minor slowdown should be fine. */
65 [ + - ]: 1780 : if (thread_id >= dbg->mem_stacks)
66 : : {
67 : 1780 : dbg->mem_tails = realloc (dbg->mem_tails, (thread_id+1)
68 : : * sizeof (struct libdw_memblock *));
69 [ - + ]: 1780 : if (dbg->mem_tails == NULL)
70 : : {
71 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl);
72 : 0 : dbg->oom_handler();
73 : : }
74 [ + + ]: 3964 : for (size_t i = dbg->mem_stacks; i <= thread_id; i++)
75 : 2184 : dbg->mem_tails[i] = NULL;
76 : 1780 : dbg->mem_stacks = thread_id + 1;
77 : 1780 : ANNOTATE_HAPPENS_BEFORE (&dbg->mem_tails);
78 : : }
79 : :
80 : 1780 : pthread_rwlock_unlock (&dbg->mem_rwl);
81 : 1780 : pthread_rwlock_rdlock (&dbg->mem_rwl);
82 : : }
83 : :
84 : : /* At this point, we have an entry in the tail array. */
85 : 6100824 : ANNOTATE_HAPPENS_AFTER (&dbg->mem_tails);
86 : 6100824 : struct libdw_memblock *result = dbg->mem_tails[thread_id];
87 [ + + ]: 6100824 : if (result == NULL)
88 : : {
89 : 1780 : result = malloc (dbg->mem_default_size);
90 [ - + ]: 1780 : if (result == NULL)
91 : : {
92 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl);
93 : 0 : dbg->oom_handler();
94 : : }
95 : 1780 : result->size = dbg->mem_default_size
96 : 1780 : - offsetof (struct libdw_memblock, mem);
97 : 1780 : result->remaining = result->size;
98 : 1780 : result->prev = NULL;
99 : 1780 : dbg->mem_tails[thread_id] = result;
100 : : }
101 : 6100824 : pthread_rwlock_unlock (&dbg->mem_rwl);
102 : 6100824 : return result;
103 : : }
104 : :
105 : : /* Can only be called after a allocation for this thread has already
106 : : been done, to possibly undo it. */
107 : : struct libdw_memblock *
108 : 0 : __libdw_thread_tail (Dwarf *dbg)
109 : : {
110 : 0 : struct libdw_memblock *result;
111 : 0 : pthread_rwlock_rdlock (&dbg->mem_rwl);
112 : 0 : result = dbg->mem_tails[thread_id];
113 : 0 : pthread_rwlock_unlock (&dbg->mem_rwl);
114 : 0 : return result;
115 : : }
116 : :
117 : : void *
118 : 56640 : __libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
119 : : {
120 : 56640 : size_t size = MAX (dbg->mem_default_size,
121 : : (align - 1 +
122 : : 2 * minsize + offsetof (struct libdw_memblock, mem)));
123 : 56640 : struct libdw_memblock *newp = malloc (size);
124 [ - + ]: 56640 : if (newp == NULL)
125 : 0 : dbg->oom_handler ();
126 : :
127 : 56640 : uintptr_t result = ((uintptr_t) newp->mem + align - 1) & ~(align - 1);
128 : :
129 : 56640 : newp->size = size - offsetof (struct libdw_memblock, mem);
130 : 56640 : newp->remaining = (uintptr_t) newp + size - (result + minsize);
131 : :
132 : 56640 : pthread_rwlock_rdlock (&dbg->mem_rwl);
133 : 56640 : newp->prev = dbg->mem_tails[thread_id];
134 : 56640 : dbg->mem_tails[thread_id] = newp;
135 : 56640 : pthread_rwlock_unlock (&dbg->mem_rwl);
136 : :
137 : 56640 : return (void *) result;
138 : : }
139 : :
140 : :
141 : : Dwarf_OOM
142 : 0 : dwarf_new_oom_handler (Dwarf *dbg, Dwarf_OOM handler)
143 : : {
144 : 0 : Dwarf_OOM old = dbg->oom_handler;
145 : 0 : dbg->oom_handler = handler;
146 : 0 : return old;
147 : : }
148 : :
149 : :
150 : : void
151 : : __attribute ((noreturn)) attribute_hidden
152 : 0 : __libdw_oom (void)
153 : : {
154 : 0 : while (1)
155 : 0 : error (EXIT_FAILURE, ENOMEM, "libdw");
156 : : }
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