1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5
6#ifndef plarena_h___
7#define plarena_h___
8/*
9 * Lifetime-based fast allocation, inspired by much prior art, including
10 * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
11 * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
12 *
13 * Also supports LIFO allocation (PL_ARENA_MARK/PL_ARENA_RELEASE).
14 */
15#include "prtypes.h"
16
17PR_BEGIN_EXTERN_C
18
19typedef struct PLArena PLArena;
20
21struct PLArena {
22 PLArena *next; /* next arena for this lifetime */
23 PRUword base; /* aligned base address, follows this header */
24 PRUword limit; /* one beyond last byte in arena */
25 PRUword avail; /* points to next available byte */
26};
27
28#ifdef PL_ARENAMETER
29typedef struct PLArenaStats PLArenaStats;
30
31struct PLArenaStats {
32 PLArenaStats *next; /* next in arenaStats list */
33 char *name; /* name for debugging */
34 PRUint32 narenas; /* number of arenas in pool */
35 PRUint32 nallocs; /* number of PL_ARENA_ALLOCATE() calls */
36 PRUint32 nreclaims; /* number of reclaims from freeArenas */
37 PRUint32 nmallocs; /* number of malloc() calls */
38 PRUint32 ndeallocs; /* number of lifetime deallocations */
39 PRUint32 ngrows; /* number of PL_ARENA_GROW() calls */
40 PRUint32 ninplace; /* number of in-place growths */
41 PRUint32 nreleases; /* number of PL_ARENA_RELEASE() calls */
42 PRUint32 nfastrels; /* number of "fast path" releases */
43 PRUint32 nbytes; /* total bytes allocated */
44 PRUint32 maxalloc; /* maximum allocation size in bytes */
45 PRFloat64 variance; /* size variance accumulator */
46};
47#endif
48
49typedef struct PLArenaPool PLArenaPool;
50
51struct PLArenaPool {
52 PLArena first; /* first arena in pool list */
53 PLArena *current; /* arena from which to allocate space */
54 PRUint32 arenasize; /* net exact size of a new arena */
55 PRUword mask; /* alignment mask (power-of-2 - 1) */
56#ifdef PL_ARENAMETER
57 PLArenaStats stats;
58#endif
59};
60
61/*
62 * WARNING: The PL_MAKE_MEM_ macros are for internal use by NSPR. Do NOT use
63 * them in your code.
64 *
65 * NOTE: Valgrind support to be added.
66 *
67 * The PL_MAKE_MEM_ macros are modeled after the MOZ_MAKE_MEM_ macros in
68 * Mozilla's mfbt/MemoryChecking.h. Only AddressSanitizer is supported now.
69 *
70 * Provides a common interface to the ASan (AddressSanitizer) and Valgrind
71 * functions used to mark memory in certain ways. In detail, the following
72 * three macros are provided:
73 *
74 * PL_MAKE_MEM_NOACCESS - Mark memory as unsafe to access (e.g. freed)
75 * PL_MAKE_MEM_UNDEFINED - Mark memory as accessible, with content undefined
76 * PL_MAKE_MEM_DEFINED - Mark memory as accessible, with content defined
77 *
78 * With Valgrind in use, these directly map to the three respective Valgrind
79 * macros. With ASan in use, the NOACCESS macro maps to poisoning the memory,
80 * while the UNDEFINED/DEFINED macros unpoison memory.
81 *
82 * With no memory checker available, all macros expand to the empty statement.
83 */
84
85/* WARNING: PL_SANITIZE_ADDRESS is for internal use by this header. Do NOT
86 * define or test this macro in your code.
87 */
88#if defined(__has_feature)
89#if __has_feature(address_sanitizer)
90#define PL_SANITIZE_ADDRESS 1
91#endif
92#elif defined(__SANITIZE_ADDRESS__)
93#define PL_SANITIZE_ADDRESS 1
94#endif
95
96#if defined(PL_SANITIZE_ADDRESS)
97
98#if defined(_MSC_VER)
99/* We can't use dllimport due to DLL linkage mismatch with
100 * sanitizer/asan_interface.h.
101 */
102#define PL_ASAN_VISIBILITY(type_) type_
103#else
104#define PL_ASAN_VISIBILITY(type_) PR_IMPORT(type_)
105#endif
106
107/* These definitions are usually provided through the
108 * sanitizer/asan_interface.h header installed by ASan.
109 * See https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning
110 */
111
112PL_ASAN_VISIBILITY(void) __asan_poison_memory_region(
113 void const volatile *addr, size_t size);
114PL_ASAN_VISIBILITY(void) __asan_unpoison_memory_region(
115 void const volatile *addr, size_t size);
116
117#define PL_MAKE_MEM_NOACCESS(addr, size) \
118 __asan_poison_memory_region((addr), (size))
119
120#define PL_MAKE_MEM_UNDEFINED(addr, size) \
121 __asan_unpoison_memory_region((addr), (size))
122
123#define PL_MAKE_MEM_DEFINED(addr, size) \
124 __asan_unpoison_memory_region((addr), (size))
125
126#else
127
128#define PL_MAKE_MEM_NOACCESS(addr, size)
129#define PL_MAKE_MEM_UNDEFINED(addr, size)
130#define PL_MAKE_MEM_DEFINED(addr, size)
131
132#endif
133
134/*
135 * If the including .c file uses only one power-of-2 alignment, it may define
136 * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
137 * per ALLOCATE and GROW.
138 */
139#ifdef PL_ARENA_CONST_ALIGN_MASK
140#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
141 & ~PL_ARENA_CONST_ALIGN_MASK)
142
143#define PL_INIT_ARENA_POOL(pool, name, size) \
144 PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
145#else
146#define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
147#endif
148
149#define PL_ARENA_ALLOCATE(p, pool, nb) \
150 PR_BEGIN_MACRO \
151 PLArena *_a = (pool)->current; \
152 PRUint32 _nb = PL_ARENA_ALIGN(pool, (PRUint32)nb); \
153 PRUword _p = _a->avail; \
154 if (_nb < (PRUint32)nb) { \
155 _p = 0; \
156 } else if (_nb > (_a->limit - _a->avail)) { \
157 _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
158 } else { \
159 _a->avail += _nb; \
160 } \
161 p = (void *)_p; \
162 if (p) { \
163 PL_MAKE_MEM_UNDEFINED(p, (PRUint32)nb); \
164 PL_ArenaCountAllocation(pool, (PRUint32)nb); \
165 } \
166 PR_END_MACRO
167
168#define PL_ARENA_GROW(p, pool, size, incr) \
169 PR_BEGIN_MACRO \
170 PLArena *_a = (pool)->current; \
171 PRUint32 _incr = PL_ARENA_ALIGN(pool, (PRUint32)incr); \
172 if (_incr < (PRUint32)incr) { \
173 p = NULL; \
174 } else if (_a->avail == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
175 _incr <= (_a->limit - _a->avail)) { \
176 PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, (PRUint32)incr); \
177 _a->avail += _incr; \
178 PL_ArenaCountInplaceGrowth(pool, size, (PRUint32)incr); \
179 } else { \
180 p = PL_ArenaGrow(pool, p, size, (PRUint32)incr); \
181 } \
182 if (p) {\
183 PL_ArenaCountGrowth(pool, size, (PRUint32)incr); \
184 } \
185 PR_END_MACRO
186
187#define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
188#define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
189
190#define PL_CLEAR_UNUSED_PATTERN(a, pattern) \
191 PR_BEGIN_MACRO \
192 PR_ASSERT((a)->avail <= (a)->limit); \
193 PL_MAKE_MEM_UNDEFINED((void*)(a)->avail, (a)->limit - (a)->avail); \
194 memset((void*)(a)->avail, (pattern), (a)->limit - (a)->avail); \
195 PR_END_MACRO
196#ifdef DEBUG
197#define PL_FREE_PATTERN 0xDA
198#define PL_CLEAR_UNUSED(a) PL_CLEAR_UNUSED_PATTERN((a), PL_FREE_PATTERN)
199#define PL_CLEAR_ARENA(a) \
200 PR_BEGIN_MACRO \
201 PL_MAKE_MEM_UNDEFINED((void*)(a), (a)->limit - (PRUword)(a)); \
202 memset((void*)(a), PL_FREE_PATTERN, (a)->limit - (PRUword)(a)); \
203 PR_END_MACRO
204#else
205#define PL_CLEAR_UNUSED(a)
206#define PL_CLEAR_ARENA(a)
207#endif
208
209#define PL_ARENA_RELEASE(pool, mark) \
210 PR_BEGIN_MACRO \
211 char *_m = (char *)(mark); \
212 PLArena *_a = (pool)->current; \
213 if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
214 _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
215 PL_CLEAR_UNUSED(_a); \
216 PL_MAKE_MEM_NOACCESS((void*)_a->avail, _a->limit - _a->avail); \
217 PL_ArenaCountRetract(pool, _m); \
218 } else { \
219 PL_ArenaRelease(pool, _m); \
220 } \
221 PL_ArenaCountRelease(pool, _m); \
222 PR_END_MACRO
223
224#ifdef PL_ARENAMETER
225#define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
226#else
227#define PL_COUNT_ARENA(pool,op)
228#endif
229
230#define PL_ARENA_DESTROY(pool, a, pnext) \
231 PR_BEGIN_MACRO \
232 PL_COUNT_ARENA(pool,--); \
233 if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
234 *(pnext) = (a)->next; \
235 PL_CLEAR_ARENA(a); \
236 free(a); \
237 (a) = 0; \
238 PR_END_MACRO
239
240/*
241** Initialize an arena pool with the given name for debugging and metering,
242** with a minimum gross size per arena of size bytes. The net size per arena
243** is smaller than the gross size by a header of four pointers plus any
244** necessary padding for alignment.
245**
246** Note: choose a gross size that's a power of two to avoid the heap allocator
247** rounding the size up.
248**/
249PR_EXTERN(void) PL_InitArenaPool(
250 PLArenaPool *pool, const char *name, PRUint32 size, PRUint32 align);
251
252/*
253** Finish using arenas, freeing all memory associated with them.
254** NOTE: this function is now a no-op. If you want to free a single
255** PLArenaPoolUse use PL_FreeArenaPool() or PL_FinishArenaPool().
256**/
257PR_EXTERN(void) PL_ArenaFinish(void);
258
259/*
260** Free the arenas in pool. The user may continue to allocate from pool
261** after calling this function. There is no need to call PL_InitArenaPool()
262** again unless PL_FinishArenaPool(pool) has been called.
263**/
264PR_EXTERN(void) PL_FreeArenaPool(PLArenaPool *pool);
265
266/*
267** Free the arenas in pool and finish using it altogether.
268**/
269PR_EXTERN(void) PL_FinishArenaPool(PLArenaPool *pool);
270
271/*
272** Compact all of the arenas in a pool so that no space is wasted.
273** NOT IMPLEMENTED. Do not use.
274**/
275PR_EXTERN(void) PL_CompactArenaPool(PLArenaPool *pool);
276
277/*
278** Friend functions used by the PL_ARENA_*() macros.
279**
280** WARNING: do not call these functions directly. Always use the
281** PL_ARENA_*() macros.
282**/
283PR_EXTERN(void *) PL_ArenaAllocate(PLArenaPool *pool, PRUint32 nb);
284
285PR_EXTERN(void *) PL_ArenaGrow(
286 PLArenaPool *pool, void *p, PRUint32 size, PRUint32 incr);
287
288PR_EXTERN(void) PL_ArenaRelease(PLArenaPool *pool, char *mark);
289
290/*
291** memset contents of all arenas in pool to pattern
292*/
293PR_EXTERN(void) PL_ClearArenaPool(PLArenaPool *pool, PRInt32 pattern);
294
295/*
296** A function like malloc_size() or malloc_usable_size() that measures the
297** size of a heap block.
298*/
299typedef size_t (*PLMallocSizeFn)(const void *ptr);
300
301/*
302** Measure all memory used by a PLArenaPool, excluding the PLArenaPool
303** structure.
304*/
305PR_EXTERN(size_t) PL_SizeOfArenaPoolExcludingPool(
306 const PLArenaPool *pool, PLMallocSizeFn mallocSizeOf);
307
308#ifdef PL_ARENAMETER
309
310#include <stdio.h>
311
312PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);
313
314PR_EXTERN(void) PL_ArenaCountInplaceGrowth(
315 PLArenaPool *pool, PRUint32 size, PRUint32 incr);
316
317PR_EXTERN(void) PL_ArenaCountGrowth(
318 PLArenaPool *pool, PRUint32 size, PRUint32 incr);
319
320PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);
321
322PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);
323
324PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);
325
326#else /* !PL_ARENAMETER */
327
328#define PL_ArenaCountAllocation(ap, nb) /* nothing */
329#define PL_ArenaCountInplaceGrowth(ap, size, incr) /* nothing */
330#define PL_ArenaCountGrowth(ap, size, incr) /* nothing */
331#define PL_ArenaCountRelease(ap, mark) /* nothing */
332#define PL_ArenaCountRetract(ap, mark) /* nothing */
333
334#endif /* !PL_ARENAMETER */
335
336PR_END_EXTERN_C
337
338#endif /* plarena_h___ */
339