1 /* -*- mode: C; c-basic-offset: 3; -*- */
2 /*
3 This file is part of drd, a thread error detector.
4
5 Copyright (C) 2006-2010 Bart Van Assche <bvanassche@acm.org>.
6
7 This program is free software; you can redistribute it and/or
8 modify it under the terms of the GNU General Public License as
9 published by the Free Software Foundation; either version 2 of the
10 License, or (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 02111-1307, USA.
21
22 The GNU General Public License is contained in the file COPYING.
23 */
24
25 /*
26 * Block allocator for second-level bitmap nodes. Each node consists of
27 * an OSetGen node and a struct bitmap2. The code below allocates
28 * NODES_PER_CHUNK nodes at a time.
29 */
30
31
32 #include "drd_basics.h" /* DRD_() */
33 #include "drd_bitmap.h" /* struct bitmap2 */
34 #include "pub_drd_bitmap.h"
35 #include "pub_tool_basics.h" /* Addr, SizeT */
36 #include "pub_tool_libcassert.h" /* tl_assert() */
37 #include "pub_tool_libcbase.h" /* VG_ROUNDUP() */
38 #include "pub_tool_libcprint.h" /* VG_(message)() */
39 #include "pub_tool_mallocfree.h" /* VG_(malloc), VG_(free) */
40
41
42 #define NODES_PER_CHUNCK 512
43
44
45 /* Local type definitions. */
46
47 struct block_allocator_chunk {
48 struct block_allocator_chunk* next;
49 struct block_allocator_chunk* prev;
50 int nallocated;
51 void* data;
52 void* data_end;
53 void* first_free;
54 };
55
56
57 /* Local variables. */
58
59 static SizeT s_bm2_node_size;
60 static struct block_allocator_chunk* s_first;
61
62
63 /* Function definitions. */
64
65 /**
66 * Allocate a new chunk and insert it at the start of the doubly-linked list
67 * s_first.
68 */
allocate_new_chunk(void)69 static struct block_allocator_chunk* allocate_new_chunk(void)
70 {
71 struct block_allocator_chunk* p;
72 int i;
73
74 tl_assert(s_bm2_node_size > 0);
75
76 p = VG_(malloc)("drd.bitmap.bac",
77 sizeof(*p) + NODES_PER_CHUNCK * s_bm2_node_size);
78 tl_assert(p);
79 p->next = s_first;
80 if (s_first)
81 p->next->prev = p;
82 s_first = p;
83 p->prev = 0;
84 p->nallocated = 0;
85 p->data = (char*)p + sizeof(*p);
86 tl_assert(p->data);
87 p->data_end = (char*)(p->data) + NODES_PER_CHUNCK * s_bm2_node_size;
88 p->first_free = p->data;
89 for (i = 0; i < NODES_PER_CHUNCK - 1; i++)
90 {
91 *(void**)((char*)(p->data) + i * s_bm2_node_size)
92 = (char*)(p->data) + (i + 1) * s_bm2_node_size;
93 }
94 tl_assert(i == NODES_PER_CHUNCK - 1);
95 *(void**)((char*)(p->data) + i * s_bm2_node_size) = NULL;
96
97 return p;
98 }
99
100 /** Free a chunk and remove it from the list of chunks. */
free_chunk(struct block_allocator_chunk * const p)101 static void free_chunk(struct block_allocator_chunk* const p)
102 {
103 tl_assert(p);
104 tl_assert(p->nallocated == 0);
105
106 if (p == s_first)
107 s_first = p->next;
108 else if (p->prev)
109 p->prev->next = p->next;
110 if (p->next)
111 p->next->prev = p->prev;
112 VG_(free)(p);
113 }
114
115 /** Allocate a node. */
DRD_(bm2_alloc_node)116 void* DRD_(bm2_alloc_node)(HChar* const ec, const SizeT szB)
117 {
118 /*
119 * If szB < sizeof(struct bitmap2) then this function has been called to
120 * allocate an AVL tree root node. Otherwise it has been called to allocate
121 * an AVL tree branch or leaf node.
122 */
123 if (szB < sizeof(struct bitmap2))
124 return VG_(malloc)(ec, szB);
125
126 while (True)
127 {
128 struct block_allocator_chunk* p;
129
130 if (s_bm2_node_size == 0)
131 s_bm2_node_size = szB;
132 else
133 tl_assert(s_bm2_node_size == szB);
134
135 for (p = s_first; p; p = p->next)
136 {
137 if (p->first_free)
138 {
139 void* result;
140
141 p->nallocated++;
142 result = p->first_free;
143 p->first_free = *(void**)(p->first_free);
144 return result;
145 }
146 }
147
148 allocate_new_chunk();
149 }
150 }
151
152 /** Free a node. */
DRD_(bm2_free_node)153 void DRD_(bm2_free_node)(void* const bm2)
154 {
155 struct block_allocator_chunk* p;
156
157 tl_assert(s_bm2_node_size > 0);
158 tl_assert(bm2);
159
160 for (p = s_first; p; p = p->next)
161 {
162 if (p->data <= bm2 && bm2 < p->data_end)
163 {
164 /* Free the memory that was allocated for a non-root AVL tree node. */
165 tl_assert(((char*)bm2 - (char*)(p->data)) % s_bm2_node_size == 0);
166 *(void**)bm2 = p->first_free;
167 p->first_free = bm2;
168 tl_assert(p->nallocated >= 1);
169 if (--(p->nallocated) == 0)
170 free_chunk(p);
171 return;
172 }
173 }
174
175 /* Free the memory that was allocated for an AVL tree root node. */
176 VG_(free)(bm2);
177 }
178