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Annotation of sbbs/include/mozilla/js/jsarena.h, revision 1.1

1.1     ! root        1: /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
        !             2:  *
        !             3:  * ***** BEGIN LICENSE BLOCK *****
        !             4:  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
        !             5:  *
        !             6:  * The contents of this file are subject to the Mozilla Public License Version
        !             7:  * 1.1 (the "License"); you may not use this file except in compliance with
        !             8:  * the License. You may obtain a copy of the License at
        !             9:  * http://www.mozilla.org/MPL/
        !            10:  *
        !            11:  * Software distributed under the License is distributed on an "AS IS" basis,
        !            12:  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
        !            13:  * for the specific language governing rights and limitations under the
        !            14:  * License.
        !            15:  *
        !            16:  * The Original Code is Mozilla Communicator client code, released
        !            17:  * March 31, 1998.
        !            18:  *
        !            19:  * The Initial Developer of the Original Code is
        !            20:  * Netscape Communications Corporation.
        !            21:  * Portions created by the Initial Developer are Copyright (C) 1998
        !            22:  * the Initial Developer. All Rights Reserved.
        !            23:  *
        !            24:  * Contributor(s):
        !            25:  *
        !            26:  * Alternatively, the contents of this file may be used under the terms of
        !            27:  * either of the GNU General Public License Version 2 or later (the "GPL"),
        !            28:  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
        !            29:  * in which case the provisions of the GPL or the LGPL are applicable instead
        !            30:  * of those above. If you wish to allow use of your version of this file only
        !            31:  * under the terms of either the GPL or the LGPL, and not to allow others to
        !            32:  * use your version of this file under the terms of the MPL, indicate your
        !            33:  * decision by deleting the provisions above and replace them with the notice
        !            34:  * and other provisions required by the GPL or the LGPL. If you do not delete
        !            35:  * the provisions above, a recipient may use your version of this file under
        !            36:  * the terms of any one of the MPL, the GPL or the LGPL.
        !            37:  *
        !            38:  * ***** END LICENSE BLOCK ***** */
        !            39: 
        !            40: #ifndef jsarena_h___
        !            41: #define jsarena_h___
        !            42: /*
        !            43:  * Lifetime-based fast allocation, inspired by much prior art, including
        !            44:  * "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
        !            45:  * David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
        !            46:  *
        !            47:  * Also supports LIFO allocation (JS_ARENA_MARK/JS_ARENA_RELEASE).
        !            48:  */
        !            49: #include <stdlib.h>
        !            50: #include "jstypes.h"
        !            51: #include "jscompat.h"
        !            52: 
        !            53: JS_BEGIN_EXTERN_C
        !            54: 
        !            55: typedef struct JSArena JSArena;
        !            56: typedef struct JSArenaPool JSArenaPool;
        !            57: 
        !            58: struct JSArena {
        !            59:     JSArena     *next;          /* next arena for this lifetime */
        !            60:     jsuword     base;           /* aligned base address, follows this header */
        !            61:     jsuword     limit;          /* one beyond last byte in arena */
        !            62:     jsuword     avail;          /* points to next available byte */
        !            63: };
        !            64: 
        !            65: #ifdef JS_ARENAMETER
        !            66: typedef struct JSArenaStats JSArenaStats;
        !            67: 
        !            68: struct JSArenaStats {
        !            69:     JSArenaStats *next;         /* next in arenaStats list */
        !            70:     char        *name;          /* name for debugging */
        !            71:     uint32      narenas;        /* number of arenas in pool */
        !            72:     uint32      nallocs;        /* number of JS_ARENA_ALLOCATE() calls */
        !            73:     uint32      nreclaims;      /* number of reclaims from freeArenas */
        !            74:     uint32      nmallocs;       /* number of malloc() calls */
        !            75:     uint32      ndeallocs;      /* number of lifetime deallocations */
        !            76:     uint32      ngrows;         /* number of JS_ARENA_GROW() calls */
        !            77:     uint32      ninplace;       /* number of in-place growths */
        !            78:     uint32      nreallocs;      /* number of arena grow extending reallocs */
        !            79:     uint32      nreleases;      /* number of JS_ARENA_RELEASE() calls */
        !            80:     uint32      nfastrels;      /* number of "fast path" releases */
        !            81:     size_t      nbytes;         /* total bytes allocated */
        !            82:     size_t      maxalloc;       /* maximum allocation size in bytes */
        !            83:     double      variance;       /* size variance accumulator */
        !            84: };
        !            85: #endif
        !            86: 
        !            87: struct JSArenaPool {
        !            88:     JSArena     first;          /* first arena in pool list */
        !            89:     JSArena     *current;       /* arena from which to allocate space */
        !            90:     size_t      arenasize;      /* net exact size of a new arena */
        !            91:     jsuword     mask;           /* alignment mask (power-of-2 - 1) */
        !            92: #ifdef JS_ARENAMETER
        !            93:     JSArenaStats stats;
        !            94: #endif
        !            95: };
        !            96: 
        !            97: /*
        !            98:  * If the including .c file uses only one power-of-2 alignment, it may define
        !            99:  * JS_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
        !           100:  * per ALLOCATE and GROW.
        !           101:  */
        !           102: #ifdef JS_ARENA_CONST_ALIGN_MASK
        !           103: #define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + JS_ARENA_CONST_ALIGN_MASK)   \
        !           104:                                  & ~(jsuword)JS_ARENA_CONST_ALIGN_MASK)
        !           105: 
        !           106: #define JS_INIT_ARENA_POOL(pool, name, size) \
        !           107:         JS_InitArenaPool(pool, name, size, JS_ARENA_CONST_ALIGN_MASK + 1)
        !           108: #else
        !           109: #define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + (pool)->mask) & ~(pool)->mask)
        !           110: #endif
        !           111: 
        !           112: #define JS_ARENA_ALLOCATE(p, pool, nb)                                        \
        !           113:     JS_ARENA_ALLOCATE_CAST(p, void *, pool, nb)
        !           114: 
        !           115: #define JS_ARENA_ALLOCATE_TYPE(p, type, pool)                                 \
        !           116:     JS_ARENA_ALLOCATE_CAST(p, type *, pool, sizeof(type))
        !           117: 
        !           118: #define JS_ARENA_ALLOCATE_CAST(p, type, pool, nb)                             \
        !           119:     JS_BEGIN_MACRO                                                            \
        !           120:         JSArena *_a = (pool)->current;                                        \
        !           121:         size_t _nb = JS_ARENA_ALIGN(pool, nb);                                \
        !           122:         jsuword _p = _a->avail;                                               \
        !           123:         jsuword _q = _p + _nb;                                                \
        !           124:         JS_ASSERT(_q >= _p);                                                  \
        !           125:         if (_q > _a->limit)                                                   \
        !           126:             _p = (jsuword)JS_ArenaAllocate(pool, _nb);                        \
        !           127:         else                                                                  \
        !           128:             _a->avail = _q;                                                   \
        !           129:         p = (type) _p;                                                        \
        !           130:         JS_ArenaCountAllocation(pool, nb);                                    \
        !           131:     JS_END_MACRO
        !           132: 
        !           133: #define JS_ARENA_GROW(p, pool, size, incr)                                    \
        !           134:     JS_ARENA_GROW_CAST(p, void *, pool, size, incr)
        !           135: 
        !           136: #define JS_ARENA_GROW_CAST(p, type, pool, size, incr)                         \
        !           137:     JS_BEGIN_MACRO                                                            \
        !           138:         JSArena *_a = (pool)->current;                                        \
        !           139:         if (_a->avail == (jsuword)(p) + JS_ARENA_ALIGN(pool, size)) {         \
        !           140:             size_t _nb = (size) + (incr);                                     \
        !           141:             jsuword _q = (jsuword)(p) + JS_ARENA_ALIGN(pool, _nb);            \
        !           142:             if (_q <= _a->limit) {                                            \
        !           143:                 _a->avail = _q;                                               \
        !           144:                 JS_ArenaCountInplaceGrowth(pool, size, incr);                 \
        !           145:             } else if ((jsuword)(p) == _a->base) {                            \
        !           146:                 p = (type) JS_ArenaRealloc(pool, p, size, incr);              \
        !           147:             } else {                                                          \
        !           148:                 p = (type) JS_ArenaGrow(pool, p, size, incr);                 \
        !           149:             }                                                                 \
        !           150:         } else {                                                              \
        !           151:             p = (type) JS_ArenaGrow(pool, p, size, incr);                     \
        !           152:         }                                                                     \
        !           153:         JS_ArenaCountGrowth(pool, size, incr);                                \
        !           154:     JS_END_MACRO
        !           155: 
        !           156: #define JS_ARENA_MARK(pool)     ((void *) (pool)->current->avail)
        !           157: #define JS_UPTRDIFF(p,q)        ((jsuword)(p) - (jsuword)(q))
        !           158: 
        !           159: #ifdef DEBUG
        !           160: #define JS_FREE_PATTERN         0xDA
        !           161: #define JS_CLEAR_UNUSED(a)      (JS_ASSERT((a)->avail <= (a)->limit),         \
        !           162:                                  memset((void*)(a)->avail, JS_FREE_PATTERN,   \
        !           163:                                         (a)->limit - (a)->avail))
        !           164: #define JS_CLEAR_ARENA(a)       memset((void*)(a), JS_FREE_PATTERN,           \
        !           165:                                        (a)->limit - (jsuword)(a))
        !           166: #else
        !           167: #define JS_CLEAR_UNUSED(a)      /* nothing */
        !           168: #define JS_CLEAR_ARENA(a)       /* nothing */
        !           169: #endif
        !           170: 
        !           171: #define JS_ARENA_RELEASE(pool, mark)                                          \
        !           172:     JS_BEGIN_MACRO                                                            \
        !           173:         char *_m = (char *)(mark);                                            \
        !           174:         JSArena *_a = (pool)->current;                                        \
        !           175:         if (_a != &(pool)->first &&                                           \
        !           176:             JS_UPTRDIFF(_m, _a->base) <= JS_UPTRDIFF(_a->avail, _a->base)) {  \
        !           177:             _a->avail = (jsuword)JS_ARENA_ALIGN(pool, _m);                    \
        !           178:             JS_ASSERT(_a->avail <= _a->limit);                                \
        !           179:             JS_CLEAR_UNUSED(_a);                                              \
        !           180:             JS_ArenaCountRetract(pool, _m);                                   \
        !           181:         } else {                                                              \
        !           182:             JS_ArenaRelease(pool, _m);                                        \
        !           183:         }                                                                     \
        !           184:         JS_ArenaCountRelease(pool, _m);                                       \
        !           185:     JS_END_MACRO
        !           186: 
        !           187: #ifdef JS_ARENAMETER
        !           188: #define JS_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
        !           189: #else
        !           190: #define JS_COUNT_ARENA(pool,op)
        !           191: #endif
        !           192: 
        !           193: #define JS_ARENA_DESTROY(pool, a, pnext)                                      \
        !           194:     JS_BEGIN_MACRO                                                            \
        !           195:         JS_COUNT_ARENA(pool,--);                                              \
        !           196:         if ((pool)->current == (a)) (pool)->current = &(pool)->first;         \
        !           197:         *(pnext) = (a)->next;                                                 \
        !           198:         JS_CLEAR_ARENA(a);                                                    \
        !           199:         free(a);                                                              \
        !           200:         (a) = NULL;                                                           \
        !           201:     JS_END_MACRO
        !           202: 
        !           203: /*
        !           204:  * Initialize an arena pool with the given name for debugging and metering,
        !           205:  * with a minimum size per arena of size bytes.
        !           206:  */
        !           207: extern JS_PUBLIC_API(void)
        !           208: JS_InitArenaPool(JSArenaPool *pool, const char *name, size_t size,
        !           209:                  size_t align);
        !           210: 
        !           211: /*
        !           212:  * Free the arenas in pool.  The user may continue to allocate from pool
        !           213:  * after calling this function.  There is no need to call JS_InitArenaPool()
        !           214:  * again unless JS_FinishArenaPool(pool) has been called.
        !           215:  */
        !           216: extern JS_PUBLIC_API(void)
        !           217: JS_FreeArenaPool(JSArenaPool *pool);
        !           218: 
        !           219: /*
        !           220:  * Free the arenas in pool and finish using it altogether.
        !           221:  */
        !           222: extern JS_PUBLIC_API(void)
        !           223: JS_FinishArenaPool(JSArenaPool *pool);
        !           224: 
        !           225: /*
        !           226:  * Finish using arenas, freeing all memory associated with them except for
        !           227:  * any locks needed for thread safety.
        !           228:  */
        !           229: extern JS_PUBLIC_API(void)
        !           230: JS_ArenaFinish(void);
        !           231: 
        !           232: /*
        !           233:  * Free any locks or other memory needed for thread safety, just before
        !           234:  * shutting down.  At that point, we must be called by a single thread.
        !           235:  *
        !           236:  * After shutting down, the next thread to call JS_InitArenaPool must not
        !           237:  * race with any other thread.  Once a pool has been initialized, threads
        !           238:  * may safely call jsarena.c functions on thread-local pools.  The upshot
        !           239:  * is that pools are per-thread, but the underlying global freelist is
        !           240:  * thread-safe, provided that both the first pool initialization and the
        !           241:  * shut-down call are single-threaded.
        !           242:  */
        !           243: extern JS_PUBLIC_API(void)
        !           244: JS_ArenaShutDown(void);
        !           245: 
        !           246: /*
        !           247:  * Friend functions used by the JS_ARENA_*() macros.
        !           248:  */
        !           249: extern JS_PUBLIC_API(void *)
        !           250: JS_ArenaAllocate(JSArenaPool *pool, size_t nb);
        !           251: 
        !           252: extern JS_PUBLIC_API(void *)
        !           253: JS_ArenaRealloc(JSArenaPool *pool, void *p, size_t size, size_t incr);
        !           254: 
        !           255: extern JS_PUBLIC_API(void *)
        !           256: JS_ArenaGrow(JSArenaPool *pool, void *p, size_t size, size_t incr);
        !           257: 
        !           258: extern JS_PUBLIC_API(void)
        !           259: JS_ArenaRelease(JSArenaPool *pool, char *mark);
        !           260: 
        !           261: /*
        !           262:  * Function to be used directly when an allocation has likely grown to consume
        !           263:  * an entire JSArena, in which case the arena is returned to the malloc heap.
        !           264:  */
        !           265: extern JS_PUBLIC_API(void)
        !           266: JS_ArenaFreeAllocation(JSArenaPool *pool, void *p, size_t size);
        !           267: 
        !           268: #ifdef JS_ARENAMETER
        !           269: 
        !           270: #include <stdio.h>
        !           271: 
        !           272: extern JS_PUBLIC_API(void)
        !           273: JS_ArenaCountAllocation(JSArenaPool *pool, size_t nb);
        !           274: 
        !           275: extern JS_PUBLIC_API(void)
        !           276: JS_ArenaCountInplaceGrowth(JSArenaPool *pool, size_t size, size_t incr);
        !           277: 
        !           278: extern JS_PUBLIC_API(void)
        !           279: JS_ArenaCountGrowth(JSArenaPool *pool, size_t size, size_t incr);
        !           280: 
        !           281: extern JS_PUBLIC_API(void)
        !           282: JS_ArenaCountRelease(JSArenaPool *pool, char *mark);
        !           283: 
        !           284: extern JS_PUBLIC_API(void)
        !           285: JS_ArenaCountRetract(JSArenaPool *pool, char *mark);
        !           286: 
        !           287: extern JS_PUBLIC_API(void)
        !           288: JS_DumpArenaStats(FILE *fp);
        !           289: 
        !           290: #else  /* !JS_ARENAMETER */
        !           291: 
        !           292: #define JS_ArenaCountAllocation(ap, nb)                 /* nothing */
        !           293: #define JS_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */
        !           294: #define JS_ArenaCountGrowth(ap, size, incr)             /* nothing */
        !           295: #define JS_ArenaCountRelease(ap, mark)                  /* nothing */
        !           296: #define JS_ArenaCountRetract(ap, mark)                  /* nothing */
        !           297: 
        !           298: #endif /* !JS_ARENAMETER */
        !           299: 
        !           300: JS_END_EXTERN_C
        !           301: 
        !           302: #endif /* jsarena_h___ */

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