The Tor Browser: nsprpub/lib/ds/plarena.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     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/. */

     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 #include "plarenas.h"

    18 PR_BEGIN_EXTERN_C

    20 typedef struct PLArena          PLArena;

    22 struct PLArena {

    23     PLArena     *next;          /* next arena for this lifetime */

    24     PRUword     base;           /* aligned base address, follows this header */

    25     PRUword     limit;          /* one beyond last byte in arena */

    26     PRUword     avail;          /* points to next available byte */

    27 };

    29 #ifdef PL_ARENAMETER

    30 typedef struct PLArenaStats PLArenaStats;

    32 struct PLArenaStats {

    33     PLArenaStats  *next;        /* next in arenaStats list */

    34     char          *name;        /* name for debugging */

    35     PRUint32      narenas;      /* number of arenas in pool */

    36     PRUint32      nallocs;      /* number of PL_ARENA_ALLOCATE() calls */

    37     PRUint32      nreclaims;    /* number of reclaims from freeArenas */

    38     PRUint32      nmallocs;     /* number of malloc() calls */

    39     PRUint32      ndeallocs;    /* number of lifetime deallocations */

    40     PRUint32      ngrows;       /* number of PL_ARENA_GROW() calls */

    41     PRUint32      ninplace;     /* number of in-place growths */

    42     PRUint32      nreleases;    /* number of PL_ARENA_RELEASE() calls */

    43     PRUint32      nfastrels;    /* number of "fast path" releases */

    44     PRUint32      nbytes;       /* total bytes allocated */

    45     PRUint32      maxalloc;     /* maximum allocation size in bytes */

    46     PRFloat64     variance;     /* size variance accumulator */

    47 };

    48 #endif

    50 struct PLArenaPool {

    51     PLArena     first;          /* first arena in pool list */

    52     PLArena     *current;       /* arena from which to allocate space */

    53     PRUint32    arenasize;      /* net exact size of a new arena */

    54     PRUword     mask;           /* alignment mask (power-of-2 - 1) */

    55 #ifdef PL_ARENAMETER

    56     PLArenaStats stats;

    57 #endif

    58 };

    60 /*

    61  * WARNING: The PL_MAKE_MEM_ macros are for internal use by NSPR. Do NOT use

    62  * them in your code.

    63  *

    64  * NOTE: Valgrind support to be added.

    65  *

    66  * The PL_MAKE_MEM_ macros are modeled after the MOZ_MAKE_MEM_ macros in

    67  * Mozilla's mfbt/MemoryChecking.h. Only AddressSanitizer is supported now.

    68  *

    69  * Provides a common interface to the ASan (AddressSanitizer) and Valgrind

    70  * functions used to mark memory in certain ways. In detail, the following

    71  * three macros are provided:

    72  *

    73  *   PL_MAKE_MEM_NOACCESS  - Mark memory as unsafe to access (e.g. freed)

    74  *   PL_MAKE_MEM_UNDEFINED - Mark memory as accessible, with content undefined

    75  *   PL_MAKE_MEM_DEFINED - Mark memory as accessible, with content defined

    76  *

    77  * With Valgrind in use, these directly map to the three respective Valgrind

    78  * macros. With ASan in use, the NOACCESS macro maps to poisoning the memory,

    79  * while the UNDEFINED/DEFINED macros unpoison memory.

    80  *

    81  * With no memory checker available, all macros expand to the empty statement.

    82  */

    84 /* WARNING: PL_SANITIZE_ADDRESS is for internal use by this header. Do NOT

    85  * define or test this macro in your code.

    86  */

    87 #if defined(__has_feature)

    88 #if __has_feature(address_sanitizer)

    89 #define PL_SANITIZE_ADDRESS 1

    90 #endif

    91 #elif defined(__SANITIZE_ADDRESS__)

    92 #define PL_SANITIZE_ADDRESS 1

    93 #endif

    95 #if defined(PL_SANITIZE_ADDRESS)

    97 /* These definitions are usually provided through the

    98  * sanitizer/asan_interface.h header installed by ASan.

    99  * See https://code.google.com/p/address-sanitizer/wiki/ManualPoisoning

   100  */

   102 void __asan_poison_memory_region(void const volatile *addr, size_t size);

   103 void __asan_unpoison_memory_region(void const volatile *addr, size_t size);

   105 #define PL_MAKE_MEM_NOACCESS(addr, size) \

   106     __asan_poison_memory_region((addr), (size))

   108 #define PL_MAKE_MEM_UNDEFINED(addr, size) \

   109     __asan_unpoison_memory_region((addr), (size))

   111 #define PL_MAKE_MEM_DEFINED(addr, size) \

   112     __asan_unpoison_memory_region((addr), (size))

   114 #else

   116 #define PL_MAKE_MEM_NOACCESS(addr, size)

   117 #define PL_MAKE_MEM_UNDEFINED(addr, size)

   118 #define PL_MAKE_MEM_DEFINED(addr, size)

   120 #endif

   122 /*

   123  * If the including .c file uses only one power-of-2 alignment, it may define

   124  * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions

   125  * per ALLOCATE and GROW.

   126  */

   127 #ifdef PL_ARENA_CONST_ALIGN_MASK

   128 #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \

   129                                 & ~PL_ARENA_CONST_ALIGN_MASK)

   131 #define PL_INIT_ARENA_POOL(pool, name, size) \

   132         PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)

   133 #else

   134 #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)

   135 #endif

   137 #define PL_ARENA_ALLOCATE(p, pool, nb) \

   138     PR_BEGIN_MACRO \

   139         PLArena *_a = (pool)->current; \

   140         PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \

   141         PRUword _p = _a->avail; \

   142         PRUword _q = _p + _nb; \

   143         if (_q > _a->limit) { \

   144             _p = (PRUword)PL_ArenaAllocate(pool, _nb); \

   145         } else { \

   146             _a->avail = _q; \

   147         } \

   148         p = (void *)_p; \

   149         PL_MAKE_MEM_UNDEFINED(p, nb); \

   150         PL_ArenaCountAllocation(pool, nb); \

   151     PR_END_MACRO

   153 #define PL_ARENA_GROW(p, pool, size, incr) \

   154     PR_BEGIN_MACRO \

   155         PLArena *_a = (pool)->current; \

   156         PRUint32 _incr = PL_ARENA_ALIGN(pool, incr); \

   157         PRUword _p = _a->avail; \

   158         PRUword _q = _p + _incr; \

   159         if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \

   160             _q <= _a->limit) { \

   161             PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, incr); \

   162             _a->avail = _q; \

   163             PL_ArenaCountInplaceGrowth(pool, size, incr); \

   164         } else { \

   165             p = PL_ArenaGrow(pool, p, size, incr); \

   166         } \

   167         PL_ArenaCountGrowth(pool, size, incr); \

   168     PR_END_MACRO

   170 #define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)

   171 #define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))

   173 #define PL_CLEAR_UNUSED_PATTERN(a, pattern) \

   174     PR_BEGIN_MACRO \

   175         PR_ASSERT((a)->avail <= (a)->limit); \

   176         PL_MAKE_MEM_UNDEFINED((void*)(a)->avail, (a)->limit - (a)->avail); \

   177         memset((void*)(a)->avail, (pattern), (a)->limit - (a)->avail); \

   178     PR_END_MACRO

   179 #ifdef DEBUG

   180 #define PL_FREE_PATTERN 0xDA

   181 #define PL_CLEAR_UNUSED(a) PL_CLEAR_UNUSED_PATTERN((a), PL_FREE_PATTERN)

   182 #define PL_CLEAR_ARENA(a) \

   183     PR_BEGIN_MACRO \

   184         PL_MAKE_MEM_UNDEFINED((void*)(a), (a)->limit - (PRUword)(a)); \

   185         memset((void*)(a), PL_FREE_PATTERN, (a)->limit - (PRUword)(a)); \

   186     PR_END_MACRO

   187 #else

   188 #define PL_CLEAR_UNUSED(a)

   189 #define PL_CLEAR_ARENA(a)

   190 #endif

   192 #define PL_ARENA_RELEASE(pool, mark) \

   193     PR_BEGIN_MACRO \

   194         char *_m = (char *)(mark); \

   195         PLArena *_a = (pool)->current; \

   196         if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \

   197             _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \

   198             PL_CLEAR_UNUSED(_a); \

   199             PL_MAKE_MEM_NOACCESS((void*)_a->avail, _a->limit - _a->avail); \

   200             PL_ArenaCountRetract(pool, _m); \

   201         } else { \

   202             PL_ArenaRelease(pool, _m); \

   203         } \

   204         PL_ArenaCountRelease(pool, _m); \

   205     PR_END_MACRO

   207 #ifdef PL_ARENAMETER

   208 #define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)

   209 #else

   210 #define PL_COUNT_ARENA(pool,op)

   211 #endif

   213 #define PL_ARENA_DESTROY(pool, a, pnext) \

   214     PR_BEGIN_MACRO \

   215         PL_COUNT_ARENA(pool,--); \

   216         if ((pool)->current == (a)) (pool)->current = &(pool)->first; \

   217         *(pnext) = (a)->next; \

   218         PL_CLEAR_ARENA(a); \

   219         free(a); \

   220         (a) = 0; \

   221     PR_END_MACRO

   223 #ifdef PL_ARENAMETER

   225 #include <stdio.h>

   227 PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);

   229 PR_EXTERN(void) PL_ArenaCountInplaceGrowth(

   230     PLArenaPool *pool, PRUint32 size, PRUint32 incr);

   232 PR_EXTERN(void) PL_ArenaCountGrowth(

   233     PLArenaPool *pool, PRUint32 size, PRUint32 incr);

   235 PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);

   237 PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);

   239 PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);

   241 #else  /* !PL_ARENAMETER */

   243 #define PL_ArenaCountAllocation(ap, nb)                 /* nothing */

   244 #define PL_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */

   245 #define PL_ArenaCountGrowth(ap, size, incr)             /* nothing */

   246 #define PL_ArenaCountRelease(ap, mark)                  /* nothing */

   247 #define PL_ArenaCountRetract(ap, mark)                  /* nothing */

   249 #endif /* !PL_ARENAMETER */

   251 PR_END_EXTERN_C

   253 #endif /* plarena_h___ */

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nsprpub/lib/ds/plarena.h@6474c204b198

nsprpub/lib/ds/plarena.h