The Tor Browser: nsprpub/lib/ds/plarena.h@7e26c7da4463 (annotated)

nsprpub/lib/ds/plarena.h@7e26c7da4463 (annotated)

nsprpub/lib/ds/plarena.h

Wed, 31 Dec 2014 06:55:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:50 +0100
changeset 2: 7e26c7da4463
permissions: -rw-r--r--

Added tag UPSTREAM_283F7C6 for changeset ca08bd8f51b2

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef plarena_h___
 #define plarena_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 (PL_ARENA_MARK/PL_ARENA_RELEASE).
  */
 #include "prtypes.h"
 #include "plarenas.h"
 PR_BEGIN_EXTERN_C
 typedef struct PLArena          PLArena;
 struct PLArena {
     PLArena     *next;          /* next arena for this lifetime */
     PRUword     base;           /* aligned base address, follows this header */
     PRUword     limit;          /* one beyond last byte in arena */
     PRUword     avail;          /* points to next available byte */
 };
 #ifdef PL_ARENAMETER
 typedef struct PLArenaStats PLArenaStats;
 struct PLArenaStats {
     PLArenaStats  *next;        /* next in arenaStats list */
     char          *name;        /* name for debugging */
     PRUint32      narenas;      /* number of arenas in pool */
     PRUint32      nallocs;      /* number of PL_ARENA_ALLOCATE() calls */
     PRUint32      nreclaims;    /* number of reclaims from freeArenas */
     PRUint32      nmallocs;     /* number of malloc() calls */
     PRUint32      ndeallocs;    /* number of lifetime deallocations */
     PRUint32      ngrows;       /* number of PL_ARENA_GROW() calls */
     PRUint32      ninplace;     /* number of in-place growths */
     PRUint32      nreleases;    /* number of PL_ARENA_RELEASE() calls */
     PRUint32      nfastrels;    /* number of "fast path" releases */
     PRUint32      nbytes;       /* total bytes allocated */
     PRUint32      maxalloc;     /* maximum allocation size in bytes */
     PRFloat64     variance;     /* size variance accumulator */
 };
 #endif
 struct PLArenaPool {
     PLArena     first;          /* first arena in pool list */
     PLArena     *current;       /* arena from which to allocate space */
     PRUint32    arenasize;      /* net exact size of a new arena */
     PRUword     mask;           /* alignment mask (power-of-2 - 1) */
 #ifdef PL_ARENAMETER
     PLArenaStats stats;
 #endif
 };
 /*
  * WARNING: The PL_MAKE_MEM_ macros are for internal use by NSPR. Do NOT use
  * them in your code.
  *
  * NOTE: Valgrind support to be added.
  *
  * The PL_MAKE_MEM_ macros are modeled after the MOZ_MAKE_MEM_ macros in
  * Mozilla's mfbt/MemoryChecking.h. Only AddressSanitizer is supported now.
  *
  * Provides a common interface to the ASan (AddressSanitizer) and Valgrind
  * functions used to mark memory in certain ways. In detail, the following
  * three macros are provided:
  *
  *   PL_MAKE_MEM_NOACCESS  - Mark memory as unsafe to access (e.g. freed)
  *   PL_MAKE_MEM_UNDEFINED - Mark memory as accessible, with content undefined
  *   PL_MAKE_MEM_DEFINED - Mark memory as accessible, with content defined
  *
  * With Valgrind in use, these directly map to the three respective Valgrind
  * macros. With ASan in use, the NOACCESS macro maps to poisoning the memory,
  * while the UNDEFINED/DEFINED macros unpoison memory.
  *
  * With no memory checker available, all macros expand to the empty statement.
  */
 /* WARNING: PL_SANITIZE_ADDRESS is for internal use by this header. Do NOT
  * define or test this macro in your code.
  */
 #if defined(__has_feature)
 #if __has_feature(address_sanitizer)
 #define PL_SANITIZE_ADDRESS 1
 #endif
 #elif defined(__SANITIZE_ADDRESS__)
 #define PL_SANITIZE_ADDRESS 1
 #endif
 #if defined(PL_SANITIZE_ADDRESS)
 /* These definitions are usually provided through the
  * sanitizer/asan_interface.h header installed by ASan.
  * See https://code.google.com/p/address-sanitizer/wiki/ManualPoisoning
  */
 void __asan_poison_memory_region(void const volatile *addr, size_t size);
 void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
 #define PL_MAKE_MEM_NOACCESS(addr, size) \
     __asan_poison_memory_region((addr), (size))
 #define PL_MAKE_MEM_UNDEFINED(addr, size) \
     __asan_unpoison_memory_region((addr), (size))
 #define PL_MAKE_MEM_DEFINED(addr, size) \
     __asan_unpoison_memory_region((addr), (size))
 #else
 #define PL_MAKE_MEM_NOACCESS(addr, size)
 #define PL_MAKE_MEM_UNDEFINED(addr, size)
 #define PL_MAKE_MEM_DEFINED(addr, size)
 #endif
 /*
  * If the including .c file uses only one power-of-2 alignment, it may define
  * PL_ARENA_CONST_ALIGN_MASK to the alignment mask and save a few instructions
  * per ALLOCATE and GROW.
  */
 #ifdef PL_ARENA_CONST_ALIGN_MASK
 #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + PL_ARENA_CONST_ALIGN_MASK) \
                                 & ~PL_ARENA_CONST_ALIGN_MASK)
 #define PL_INIT_ARENA_POOL(pool, name, size) \
         PL_InitArenaPool(pool, name, size, PL_ARENA_CONST_ALIGN_MASK + 1)
 #else
 #define PL_ARENA_ALIGN(pool, n) (((PRUword)(n) + (pool)->mask) & ~(pool)->mask)
 #endif
 #define PL_ARENA_ALLOCATE(p, pool, nb) \
     PR_BEGIN_MACRO \
         PLArena *_a = (pool)->current; \
         PRUint32 _nb = PL_ARENA_ALIGN(pool, nb); \
         PRUword _p = _a->avail; \
         PRUword _q = _p + _nb; \
         if (_q > _a->limit) { \
             _p = (PRUword)PL_ArenaAllocate(pool, _nb); \
         } else { \
             _a->avail = _q; \
         } \
         p = (void *)_p; \
         PL_MAKE_MEM_UNDEFINED(p, nb); \
         PL_ArenaCountAllocation(pool, nb); \
     PR_END_MACRO
 #define PL_ARENA_GROW(p, pool, size, incr) \
     PR_BEGIN_MACRO \
         PLArena *_a = (pool)->current; \
         PRUint32 _incr = PL_ARENA_ALIGN(pool, incr); \
         PRUword _p = _a->avail; \
         PRUword _q = _p + _incr; \
         if (_p == (PRUword)(p) + PL_ARENA_ALIGN(pool, size) && \
             _q <= _a->limit) { \
             PL_MAKE_MEM_UNDEFINED((unsigned char *)(p) + size, incr); \
             _a->avail = _q; \
             PL_ArenaCountInplaceGrowth(pool, size, incr); \
         } else { \
             p = PL_ArenaGrow(pool, p, size, incr); \
         } \
         PL_ArenaCountGrowth(pool, size, incr); \
     PR_END_MACRO
 #define PL_ARENA_MARK(pool) ((void *) (pool)->current->avail)
 #define PR_UPTRDIFF(p,q) ((PRUword)(p) - (PRUword)(q))
 #define PL_CLEAR_UNUSED_PATTERN(a, pattern) \
     PR_BEGIN_MACRO \
         PR_ASSERT((a)->avail <= (a)->limit); \
         PL_MAKE_MEM_UNDEFINED((void*)(a)->avail, (a)->limit - (a)->avail); \
         memset((void*)(a)->avail, (pattern), (a)->limit - (a)->avail); \
     PR_END_MACRO
 #ifdef DEBUG
 #define PL_FREE_PATTERN 0xDA
 #define PL_CLEAR_UNUSED(a) PL_CLEAR_UNUSED_PATTERN((a), PL_FREE_PATTERN)
 #define PL_CLEAR_ARENA(a) \
     PR_BEGIN_MACRO \
         PL_MAKE_MEM_UNDEFINED((void*)(a), (a)->limit - (PRUword)(a)); \
         memset((void*)(a), PL_FREE_PATTERN, (a)->limit - (PRUword)(a)); \
     PR_END_MACRO
 #else
 #define PL_CLEAR_UNUSED(a)
 #define PL_CLEAR_ARENA(a)
 #endif
 #define PL_ARENA_RELEASE(pool, mark) \
     PR_BEGIN_MACRO \
         char *_m = (char *)(mark); \
         PLArena *_a = (pool)->current; \
         if (PR_UPTRDIFF(_m, _a->base) <= PR_UPTRDIFF(_a->avail, _a->base)) { \
             _a->avail = (PRUword)PL_ARENA_ALIGN(pool, _m); \
             PL_CLEAR_UNUSED(_a); \
             PL_MAKE_MEM_NOACCESS((void*)_a->avail, _a->limit - _a->avail); \
             PL_ArenaCountRetract(pool, _m); \
         } else { \
             PL_ArenaRelease(pool, _m); \
         } \
         PL_ArenaCountRelease(pool, _m); \
     PR_END_MACRO
 #ifdef PL_ARENAMETER
 #define PL_COUNT_ARENA(pool,op) ((pool)->stats.narenas op)
 #else
 #define PL_COUNT_ARENA(pool,op)
 #endif
 #define PL_ARENA_DESTROY(pool, a, pnext) \
     PR_BEGIN_MACRO \
         PL_COUNT_ARENA(pool,--); \
         if ((pool)->current == (a)) (pool)->current = &(pool)->first; \
         *(pnext) = (a)->next; \
         PL_CLEAR_ARENA(a); \
         free(a); \
         (a) = 0; \
     PR_END_MACRO
 #ifdef PL_ARENAMETER
 #include <stdio.h>
 PR_EXTERN(void) PL_ArenaCountAllocation(PLArenaPool *pool, PRUint32 nb);
 PR_EXTERN(void) PL_ArenaCountInplaceGrowth(
     PLArenaPool *pool, PRUint32 size, PRUint32 incr);
 PR_EXTERN(void) PL_ArenaCountGrowth(
     PLArenaPool *pool, PRUint32 size, PRUint32 incr);
 PR_EXTERN(void) PL_ArenaCountRelease(PLArenaPool *pool, char *mark);
 PR_EXTERN(void) PL_ArenaCountRetract(PLArenaPool *pool, char *mark);
 PR_EXTERN(void) PL_DumpArenaStats(FILE *fp);
 #else  /* !PL_ARENAMETER */
 #define PL_ArenaCountAllocation(ap, nb)                 /* nothing */
 #define PL_ArenaCountInplaceGrowth(ap, size, incr)      /* nothing */
 #define PL_ArenaCountGrowth(ap, size, incr)             /* nothing */
 #define PL_ArenaCountRelease(ap, mark)                  /* nothing */
 #define PL_ArenaCountRetract(ap, mark)                  /* nothing */
 #endif /* !PL_ARENAMETER */
 PR_END_EXTERN_C
 #endif /* plarena_h___ */

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nsprpub/lib/ds/plarena.h@7e26c7da4463 (annotated)

nsprpub/lib/ds/plarena.h