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 "atomics.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 = ATOMIC_VAR_INIT(0);
49 :
50 : struct libdw_memblock *
51 2141148 : __libdw_alloc_tail (Dwarf *dbg)
52 : {
53 2141148 : if (thread_id == THREAD_ID_UNSET)
54 412 : thread_id = atomic_fetch_add (&next_id, 1);
55 :
56 2141148 : pthread_rwlock_rdlock (&dbg->mem_rwl);
57 2141148 : if (thread_id >= dbg->mem_stacks)
58 : {
59 558 : pthread_rwlock_unlock (&dbg->mem_rwl);
60 558 : 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. */
65 558 : if (thread_id >= dbg->mem_stacks)
66 : {
67 558 : dbg->mem_tails = realloc (dbg->mem_tails, (thread_id+1)
68 : * sizeof (struct libdw_memblock *));
69 558 : if (dbg->mem_tails == NULL)
70 : {
71 0 : pthread_rwlock_unlock (&dbg->mem_rwl);
72 0 : dbg->oom_handler();
73 : }
74 1132 : for (size_t i = dbg->mem_stacks; i <= thread_id; i++)
75 574 : dbg->mem_tails[i] = NULL;
76 558 : dbg->mem_stacks = thread_id + 1;
77 558 : ANNOTATE_HAPPENS_BEFORE (&dbg->mem_tails);
78 : }
79 :
80 558 : pthread_rwlock_unlock (&dbg->mem_rwl);
81 558 : pthread_rwlock_rdlock (&dbg->mem_rwl);
82 : }
83 :
84 : /* At this point, we have an entry in the tail array. */
85 2141148 : ANNOTATE_HAPPENS_AFTER (&dbg->mem_tails);
86 2141148 : struct libdw_memblock *result = dbg->mem_tails[thread_id];
87 2141148 : if (result == NULL)
88 : {
89 558 : result = malloc (dbg->mem_default_size);
90 558 : if (result == NULL)
91 : {
92 0 : pthread_rwlock_unlock (&dbg->mem_rwl);
93 0 : dbg->oom_handler();
94 : }
95 1116 : result->size = dbg->mem_default_size
96 558 : - offsetof (struct libdw_memblock, mem);
97 558 : result->remaining = result->size;
98 558 : result->prev = NULL;
99 558 : dbg->mem_tails[thread_id] = result;
100 : }
101 2141148 : pthread_rwlock_unlock (&dbg->mem_rwl);
102 2141148 : 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 18361 : __libdw_allocate (Dwarf *dbg, size_t minsize, size_t align)
119 : {
120 18361 : size_t size = MAX (dbg->mem_default_size,
121 : (align - 1 +
122 : 2 * minsize + offsetof (struct libdw_memblock, mem)));
123 18361 : struct libdw_memblock *newp = malloc (size);
124 18361 : if (newp == NULL)
125 0 : dbg->oom_handler ();
126 :
127 18361 : uintptr_t result = ((uintptr_t) newp->mem + align - 1) & ~(align - 1);
128 :
129 18361 : newp->size = size - offsetof (struct libdw_memblock, mem);
130 18361 : newp->remaining = (uintptr_t) newp + size - (result + minsize);
131 :
132 18361 : pthread_rwlock_rdlock (&dbg->mem_rwl);
133 18361 : newp->prev = dbg->mem_tails[thread_id];
134 18361 : dbg->mem_tails[thread_id] = newp;
135 18361 : pthread_rwlock_unlock (&dbg->mem_rwl);
136 :
137 18361 : 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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