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RetroZilla/js/src/jsarena.h

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef jsarena_h___
#define jsarena_h___
/*
* Lifetime-based fast allocation, inspired by much prior art, including
* "Fast Allocation and Deallocation of Memory Based on Object Lifetimes"
* David R. Hanson, Software -- Practice and Experience, Vol. 20(1).
*
* Also supports LIFO allocation (JS_ARENA_MARK/JS_ARENA_RELEASE).
*/
#include <stdlib.h>
#include "jstypes.h"
#include "jscompat.h"
JS_BEGIN_EXTERN_C
typedef struct JSArena JSArena;
typedef struct JSArenaPool JSArenaPool;
struct JSArena {
JSArena *next; /* next arena for this lifetime */
jsuword base; /* aligned base address, follows this header */
jsuword limit; /* one beyond last byte in arena */
jsuword avail; /* points to next available byte */
};
#ifdef JS_ARENAMETER
typedef struct JSArenaStats JSArenaStats;
struct JSArenaStats {
JSArenaStats *next; /* next in arenaStats list */
char *name; /* name for debugging */
uint32 narenas; /* number of arenas in pool */
uint32 nallocs; /* number of JS_ARENA_ALLOCATE() calls */
uint32 nmallocs; /* number of malloc() calls */
uint32 ndeallocs; /* number of lifetime deallocations */
uint32 ngrows; /* number of JS_ARENA_GROW() calls */
uint32 ninplace; /* number of in-place growths */
uint32 nreallocs; /* number of arena grow extending reallocs */
uint32 nreleases; /* number of JS_ARENA_RELEASE() calls */
uint32 nfastrels; /* number of "fast path" releases */
size_t nbytes; /* total bytes allocated */
size_t maxalloc; /* maximum allocation size in bytes */
double variance; /* size variance accumulator */
};
#endif
struct JSArenaPool {
JSArena first; /* first arena in pool list */
JSArena *current; /* arena from which to allocate space */
size_t arenasize; /* net exact size of a new arena */
jsuword mask; /* alignment mask (power-of-2 - 1) */
#ifdef JS_ARENAMETER
JSArenaStats stats;
#endif
};
/*
* If the including .c file uses only one power-of-2 alignment, it may define
* JS_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
* per ALLOCATE and GROW.
*/
#ifdef JS_ARENA_CONST_ALIGN_MASK
#define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + JS_ARENA_CONST_ALIGN_MASK) \
& ~(jsuword)JS_ARENA_CONST_ALIGN_MASK)
#define JS_INIT_ARENA_POOL(pool, name, size) \
JS_InitArenaPool(pool, name, size, JS_ARENA_CONST_ALIGN_MASK + 1)
#else
#define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + (pool)->mask) & ~(pool)->mask)
#endif
#define JS_ARENA_ALLOCATE(p, pool, nb) \
JS_ARENA_ALLOCATE_CAST(p, void *, pool, nb)
#define JS_ARENA_ALLOCATE_TYPE(p, type, pool) \
JS_ARENA_ALLOCATE_COMMON(p, type *, pool, sizeof(type), 0)
#define JS_ARENA_ALLOCATE_CAST(p, type, pool, nb) \
JS_ARENA_ALLOCATE_COMMON(p, type, pool, nb, _nb > _a->limit)
/*
* NB: In JS_ARENA_ALLOCATE_CAST and JS_ARENA_GROW_CAST, always subtract _nb
* from a->limit rather than adding _nb to _p, to avoid overflowing a 32-bit
* address space (possible when running a 32-bit program on a 64-bit system
* where the kernel maps the heap up against the top of the 32-bit address
* space).
*
* Thanks to Juergen Kreileder <jk@blackdown.de>, who brought this up in
* https://bugzilla.mozilla.org/show_bug.cgi?id=279273.
*/
#define JS_ARENA_ALLOCATE_COMMON(p, type, pool, nb, guard) \
JS_BEGIN_MACRO \
JSArena *_a = (pool)->current; \
size_t _nb = JS_ARENA_ALIGN(pool, nb); \
jsuword _p = _a->avail; \
if ((guard) || _p > _a->limit - _nb) \
_p = (jsuword)JS_ArenaAllocate(pool, _nb); \
else \
_a->avail = _p + _nb; \
p = (type) _p; \
JS_ArenaCountAllocation(pool, nb); \
JS_END_MACRO
#define JS_ARENA_GROW(p, pool, size, incr) \
JS_ARENA_GROW_CAST(p, void *, pool, size, incr)
#define JS_ARENA_GROW_CAST(p, type, pool, size, incr) \
JS_BEGIN_MACRO \
JSArena *_a = (pool)->current; \
if (_a->avail == (jsuword)(p) + JS_ARENA_ALIGN(pool, size)) { \
size_t _nb = (size) + (incr); \
_nb = JS_ARENA_ALIGN(pool, _nb); \
if (_a->limit >= _nb && (jsuword)(p) <= _a->limit - _nb) { \
_a->avail = (jsuword)(p) + _nb; \
JS_ArenaCountInplaceGrowth(pool, size, incr); \
} else if ((jsuword)(p) == _a->base) { \
p = (type) JS_ArenaRealloc(pool, p, size, incr); \
} else { \
p = (type) JS_ArenaGrow(pool, p, size, incr); \
} \
} else { \
p = (type) JS_ArenaGrow(pool, p, size, incr); \
} \
JS_ArenaCountGrowth(pool, size, incr); \
JS_END_MACRO
#define JS_ARENA_MARK(pool) ((void *) (pool)->current->avail)
#define JS_UPTRDIFF(p,q) ((jsuword)(p) - (jsuword)(q))
#ifdef DEBUG
#define JS_FREE_PATTERN 0xDA
#define JS_CLEAR_UNUSED(a) (JS_ASSERT((a)->avail <= (a)->limit), \
memset((void*)(a)->avail, JS_FREE_PATTERN, \
(a)->limit - (a)->avail))
#define JS_CLEAR_ARENA(a) memset((void*)(a), JS_FREE_PATTERN, \
(a)->limit - (jsuword)(a))
#else
#define JS_CLEAR_UNUSED(a) /* nothing */
#define JS_CLEAR_ARENA(a) /* nothing */
#endif
#define JS_ARENA_RELEASE(pool, mark) \
JS_BEGIN_MACRO \
char *_m = (char *)(mark); \
JSArena *_a = (pool)->current; \
if (_a != &(pool)->first && \
JS_UPTRDIFF(_m, _a->base) <= JS_UPTRDIFF(_a->avail, _a->base)) { \
_a->avail = (jsuword)JS_ARENA_ALIGN(pool, _m); \
JS_ASSERT(_a->avail <= _a->limit); \
JS_CLEAR_UNUSED(_a); \
JS_ArenaCountRetract(pool, _m); \
} else { \
JS_ArenaRelease(pool, _m); \
} \
JS_ArenaCountRelease(pool, _m); \
JS_END_MACRO
#ifdef JS_ARENAMETER
#define JS_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
#else
#define JS_COUNT_ARENA(pool,op)
#endif
#define JS_ARENA_DESTROY(pool, a, pnext) \
JS_BEGIN_MACRO \
JS_COUNT_ARENA(pool,--); \
if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
*(pnext) = (a)->next; \
JS_CLEAR_ARENA(a); \
free(a); \
(a) = NULL; \
JS_END_MACRO
/*
* Initialize an arena pool with the given name for debugging and metering,
* with a minimum size per arena of size bytes.
*/
extern JS_PUBLIC_API(void)
JS_InitArenaPool(JSArenaPool *pool, const char *name, size_t size,
size_t align);
/*
* Free the arenas in pool. The user may continue to allocate from pool
* after calling this function. There is no need to call JS_InitArenaPool()
* again unless JS_FinishArenaPool(pool) has been called.
*/
extern JS_PUBLIC_API(void)
JS_FreeArenaPool(JSArenaPool *pool);
/*
* Free the arenas in pool and finish using it altogether.
*/
extern JS_PUBLIC_API(void)
JS_FinishArenaPool(JSArenaPool *pool);
/*
* Deprecated do-nothing function.
*/
extern JS_PUBLIC_API(void)
JS_ArenaFinish(void);
/*
* Deprecated do-nothing function.
*/
extern JS_PUBLIC_API(void)
JS_ArenaShutDown(void);
/*
* Friend functions used by the JS_ARENA_*() macros.
*/
extern JS_PUBLIC_API(void *)
JS_ArenaAllocate(JSArenaPool *pool, size_t nb);
extern JS_PUBLIC_API(void *)
JS_ArenaRealloc(JSArenaPool *pool, void *p, size_t size, size_t incr);
extern JS_PUBLIC_API(void *)
JS_ArenaGrow(JSArenaPool *pool, void *p, size_t size, size_t incr);
extern JS_PUBLIC_API(void)
JS_ArenaRelease(JSArenaPool *pool, char *mark);
/*
* Function to be used directly when an allocation has likely grown to consume
* an entire JSArena, in which case the arena is returned to the malloc heap.
*/
extern JS_PUBLIC_API(void)
JS_ArenaFreeAllocation(JSArenaPool *pool, void *p, size_t size);
#ifdef JS_ARENAMETER
#include <stdio.h>
extern JS_PUBLIC_API(void)
JS_ArenaCountAllocation(JSArenaPool *pool, size_t nb);
extern JS_PUBLIC_API(void)
JS_ArenaCountInplaceGrowth(JSArenaPool *pool, size_t size, size_t incr);
extern JS_PUBLIC_API(void)
JS_ArenaCountGrowth(JSArenaPool *pool, size_t size, size_t incr);
extern JS_PUBLIC_API(void)
JS_ArenaCountRelease(JSArenaPool *pool, char *mark);
extern JS_PUBLIC_API(void)
JS_ArenaCountRetract(JSArenaPool *pool, char *mark);
extern JS_PUBLIC_API(void)
JS_DumpArenaStats(FILE *fp);
#else /* !JS_ARENAMETER */
#define JS_ArenaCountAllocation(ap, nb) /* nothing */
#define JS_ArenaCountInplaceGrowth(ap, size, incr) /* nothing */
#define JS_ArenaCountGrowth(ap, size, incr) /* nothing */
#define JS_ArenaCountRelease(ap, mark) /* nothing */
#define JS_ArenaCountRetract(ap, mark) /* nothing */
#endif /* !JS_ARENAMETER */
JS_END_EXTERN_C
#endif /* jsarena_h___ */
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