https://github.com/mozilla/gecko-dev
Tip revision: 735e768d0b6231997d95cf9ecc43a1fb3c1faafc authored by ffxbld on 13 December 2011, 01:58:11 UTC
Added tag FENNEC_9_0b6_BUILD1 for changeset 541d40f07d00. CLOSED TREE a=release
Added tag FENNEC_9_0b6_BUILD1 for changeset 541d40f07d00. CLOSED TREE a=release
Tip revision: 735e768
jsarena.h
/* -*- 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"
#include "jsstaticcheck.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 */
};
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) */
};
#define JS_ARENA_ALIGN(pool, n) (((jsuword)(n) + (pool)->mask) & ~(pool)->mask)
#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 overflow (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, see bug 279273). Note that
* this necessitates a comparison between nb and a->limit that looks like a
* (conceptual) type error but isn't.
*/
#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; \
STATIC_ASSUME(!p || ubound((char *)p) >= 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)) { \
/* p was the last thing allocated in the current arena... */ \
size_t _nb = (size) + (incr); \
_nb = JS_ARENA_ALIGN(pool, _nb); \
if (_a->limit >= _nb && (jsuword)(p) <= _a->limit - _nb) { \
/* ... and we have space, so just extend p in-place */ \
_a->avail = (jsuword)(p) + _nb; \
} else if ((jsuword)(p) == _a->base) { \
/* ... p is also the 1st thing in this arena */ \
p = (type) JS_ArenaRealloc(pool, p, size, incr); \
} else { \
/* hard case */ \
p = (type) JS_ArenaGrow(pool, p, size, incr); \
} \
} else { \
/* hard case */ \
p = (type) JS_ArenaGrow(pool, p, size, incr); \
} \
STATIC_ASSUME(!p || ubound((char *)p) >= size + incr); \
JS_END_MACRO
#define JS_ARENA_MARK(pool) ((void *) (pool)->current->avail)
#define JS_UPTRDIFF(p,q) ((jsuword)(p) - (jsuword)(q))
/*
* Check if the mark is inside arena's allocated area.
*/
#define JS_IS_IN_ARENA(a, mark) \
(JS_UPTRDIFF(mark, (a)->base) <= JS_UPTRDIFF((a)->avail, (a)->base))
#ifdef DEBUG
#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_IS_IN_ARENA(_a, _m)) { \
_a->avail = (jsuword)JS_ARENA_ALIGN(pool, _m); \
JS_ASSERT(_a->avail <= _a->limit); \
JS_CLEAR_UNUSED(_a); \
} else { \
JS_ArenaRelease(pool, _m); \
} \
JS_END_MACRO
#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); \
js::UnwantedForeground::free_(a); \
(a) = NULL; \
JS_END_MACRO
/*
* Initialize an arena pool with a minimum size per arena of |size| bytes.
* |align| must be 1, 2, 4 or 8.
*/
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);
JS_END_EXTERN_C
#ifdef __cplusplus
namespace js {
template <typename T>
inline T *
ArenaArray(JSArenaPool &pool, unsigned count)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, count * sizeof(T));
return (T *) v;
}
template <typename T>
inline T *
ArenaNew(JSArenaPool &pool)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T() : NULL;
}
template <typename T, typename A>
inline T *
ArenaNew(JSArenaPool &pool, const A &a)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T(a) : NULL;
}
template <typename T, typename A, typename B>
inline T *
ArenaNew(JSArenaPool &pool, const A &a, const B &b)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T(a, b) : NULL;
}
template <typename T, typename A, typename B, typename C>
inline T *
ArenaNew(JSArenaPool &pool, const A &a, const B &b, const C &c)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T(a, b, c) : NULL;
}
template <typename T, typename A, typename B, typename C, typename D>
inline T *
ArenaNew(JSArenaPool &pool, const A &a, const B &b, const C &c, const D &d)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T(a, b, c, d) : NULL;
}
template <typename T, typename A, typename B, typename C, typename D, typename E>
inline T *
ArenaNew(JSArenaPool &pool, const A &a, const B &b, const C &c, const D &d, const E &e)
{
void *v;
JS_ARENA_ALLOCATE(v, &pool, sizeof(T));
return v ? new (v) T(a, b, c, d, e) : NULL;
}
inline uintN
ArenaAllocatedSize(const JSArenaPool &pool)
{
uintN res = 0;
const JSArena *a = &pool.first;
while (a) {
res += (a->limit - (jsuword)a);
a = a->next;
}
return res;
}
/* Move the contents of oldPool into newPool, and reset oldPool. */
inline void
MoveArenaPool(JSArenaPool *oldPool, JSArenaPool *newPool)
{
*newPool = *oldPool;
JS_InitArenaPool(oldPool, NULL, newPool->arenasize, newPool->mask + 1);
}
} /* namespace js */
#endif /* __cplusplus */
#endif /* jsarena_h___ */