dlmalloc-merged.c

eCos/RedBoot for勤研ARM AnywhereII(4510) 含全部源代码



/* 
  Dealing with use bits 
*/

/* extract p's inuse bit */

#define inuse(p)\
((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE)

/* extract inuse bit of previous chunk */

#define prev_inuse(p)  ((p)->size & PREV_INUSE)

/* check for mmap()'ed chunk */

#define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED)

/* set/clear chunk as in use without otherwise disturbing */

#define set_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE

#define clear_inuse(p)\
((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE)

/* check/set/clear inuse bits in known places */

#define inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE)

#define set_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE)

#define clear_inuse_bit_at_offset(p, s)\
 (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE))




/* 
  Dealing with size fields 
*/

/* Get size, ignoring use bits */

#define chunksize(p)          ((p)->size & ~(SIZE_BITS))

/* Set size at head, without disturbing its use bit */

#define set_head_size(p, s)   ((p)->size = (((p)->size & PREV_INUSE) | (s)))

/* Set size/use ignoring previous bits in header */

#define set_head(p, s)        ((p)->size = (s))

/* Set size at footer (only when chunk is not in use) */

#define set_foot(p, s)   (((mchunkptr)((char*)(p) + (s)))->prev_size = (s))





/*
   Bins

    The bins, `av_' are an array of pairs of pointers serving as the
    heads of (initially empty) doubly-linked lists of chunks, laid out
    in a way so that each pair can be treated as if it were in a
    malloc_chunk. (This way, the fd/bk offsets for linking bin heads
    and chunks are the same).

    Bins for sizes < 512 bytes contain chunks of all the same size, spaced
    8 bytes apart. Larger bins are approximately logarithmically
    spaced. (See the table below.) The `av_' array is never mentioned
    directly in the code, but instead via bin access macros.

    Bin layout:

    64 bins of size       8
    32 bins of size      64
    16 bins of size     512
     8 bins of size    4096
     4 bins of size   32768
     2 bins of size  262144
     1 bin  of size what's left

    There is actually a little bit of slop in the numbers in bin_index
    for the sake of speed. This makes no difference elsewhere.

    The special chunks `top' and `last_remainder' get their own bins,
    (this is implemented via yet more trickery with the av_ array),
    although `top' is never properly linked to its bin since it is
    always handled specially.

*/

#ifdef SEPARATE_OBJECTS
#define av_ malloc_av_
#endif

#define NAV             128   /* number of bins */

typedef struct malloc_chunk* mbinptr;

/* access macros */

#define bin_at(i)      ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ))
#define next_bin(b)    ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr)))
#define prev_bin(b)    ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr)))

/*
   The first 2 bins are never indexed. The corresponding av_ cells are instead
   used for bookkeeping. This is not to save space, but to simplify
   indexing, maintain locality, and avoid some initialization tests.
*/

#define top            (bin_at(0)->fd)   /* The topmost chunk */
#define last_remainder (bin_at(1))       /* remainder from last split */


/*
   Because top initially points to its own bin with initial
   zero size, thus forcing extension on the first malloc request, 
   we avoid having any special code in malloc to check whether 
   it even exists yet. But we still need to in malloc_extend_top.
*/

#define initial_top    ((mchunkptr)(bin_at(0)))

/* Helper macro to initialize bins */

#define IAV(i)  bin_at(i), bin_at(i)

#ifdef DEFINE_MALLOC
STATIC mbinptr av_[NAV * 2 + 2] = {
 0, 0,
 IAV(0),   IAV(1),   IAV(2),   IAV(3),   IAV(4),   IAV(5),   IAV(6),   IAV(7),
 IAV(8),   IAV(9),   IAV(10),  IAV(11),  IAV(12),  IAV(13),  IAV(14),  IAV(15),
 IAV(16),  IAV(17),  IAV(18),  IAV(19),  IAV(20),  IAV(21),  IAV(22),  IAV(23),
 IAV(24),  IAV(25),  IAV(26),  IAV(27),  IAV(28),  IAV(29),  IAV(30),  IAV(31),
 IAV(32),  IAV(33),  IAV(34),  IAV(35),  IAV(36),  IAV(37),  IAV(38),  IAV(39),
 IAV(40),  IAV(41),  IAV(42),  IAV(43),  IAV(44),  IAV(45),  IAV(46),  IAV(47),
 IAV(48),  IAV(49),  IAV(50),  IAV(51),  IAV(52),  IAV(53),  IAV(54),  IAV(55),
 IAV(56),  IAV(57),  IAV(58),  IAV(59),  IAV(60),  IAV(61),  IAV(62),  IAV(63),
 IAV(64),  IAV(65),  IAV(66),  IAV(67),  IAV(68),  IAV(69),  IAV(70),  IAV(71),
 IAV(72),  IAV(73),  IAV(74),  IAV(75),  IAV(76),  IAV(77),  IAV(78),  IAV(79),
 IAV(80),  IAV(81),  IAV(82),  IAV(83),  IAV(84),  IAV(85),  IAV(86),  IAV(87),
 IAV(88),  IAV(89),  IAV(90),  IAV(91),  IAV(92),  IAV(93),  IAV(94),  IAV(95),
 IAV(96),  IAV(97),  IAV(98),  IAV(99),  IAV(100), IAV(101), IAV(102), IAV(103),
 IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111),
 IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119),
 IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127)
};
#else
extern mbinptr av_[NAV * 2 + 2];
#endif



/* field-extraction macros */

#define first(b) ((b)->fd)
#define last(b)  ((b)->bk)

/* 
  Indexing into bins
*/

#define bin_index(sz)                                                          \
(((((unsigned long)(sz)) >> 9) ==    0) ?       (((unsigned long)(sz)) >>  3): \
 ((((unsigned long)(sz)) >> 9) <=    4) ?  56 + (((unsigned long)(sz)) >>  6): \
 ((((unsigned long)(sz)) >> 9) <=   20) ?  91 + (((unsigned long)(sz)) >>  9): \
 ((((unsigned long)(sz)) >> 9) <=   84) ? 110 + (((unsigned long)(sz)) >> 12): \
 ((((unsigned long)(sz)) >> 9) <=  340) ? 119 + (((unsigned long)(sz)) >> 15): \
 ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \
                                          126)                     
/* 
  bins for chunks < 512 are all spaced SMALLBIN_WIDTH bytes apart, and hold
  identically sized chunks. This is exploited in malloc.
*/

#define MAX_SMALLBIN_SIZE   512
#define SMALLBIN_WIDTH        8
#define SMALLBIN_WIDTH_BITS   3
#define MAX_SMALLBIN        (MAX_SMALLBIN_SIZE / SMALLBIN_WIDTH) - 1

#define smallbin_index(sz)  (((unsigned long)(sz)) >> SMALLBIN_WIDTH_BITS)

/* 
   Requests are `small' if both the corresponding and the next bin are small
*/

#define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH)



/*
    To help compensate for the large number of bins, a one-level index
    structure is used for bin-by-bin searching.  `binblocks' is a
    one-word bitvector recording whether groups of BINBLOCKWIDTH bins
    have any (possibly) non-empty bins, so they can be skipped over
    all at once during during traversals. The bits are NOT always
    cleared as soon as all bins in a block are empty, but instead only
    when all are noticed to be empty during traversal in malloc.
*/

#define BINBLOCKWIDTH     4   /* bins per block */

#define binblocks      (bin_at(0)->size) /* bitvector of nonempty blocks */

/* bin<->block macros */

#define idx2binblock(ix)    ((unsigned long)1 << (ix / BINBLOCKWIDTH))
#define mark_binblock(ii)   (binblocks |= idx2binblock(ii))
#define clear_binblock(ii)  (binblocks &= ~(idx2binblock(ii)))





/*  Other static bookkeeping data */

#ifdef SEPARATE_OBJECTS
#define trim_threshold		malloc_trim_threshold
#define top_pad			malloc_top_pad
#define n_mmaps_max		malloc_n_mmaps_max
#define mmap_threshold		malloc_mmap_threshold
#define sbrk_base		malloc_sbrk_base
#define max_sbrked_mem		malloc_max_sbrked_mem
#define max_total_mem		malloc_max_total_mem
#define current_mallinfo	malloc_current_mallinfo
#define n_mmaps			malloc_n_mmaps
#define max_n_mmaps		malloc_max_n_mmaps
#define mmapped_mem		malloc_mmapped_mem
#define max_mmapped_mem		malloc_max_mmapped_mem
#endif

/* variables holding tunable values */

#ifdef DEFINE_MALLOC

STATIC unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
STATIC unsigned long top_pad          = DEFAULT_TOP_PAD;
#if HAVE_MMAP
STATIC unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
STATIC unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
#endif

/* The first value returned from sbrk */
STATIC char* sbrk_base = (char*)(-1);

/* The maximum memory obtained from system via sbrk */
STATIC unsigned long max_sbrked_mem = 0; 

/* The maximum via either sbrk or mmap */
STATIC unsigned long max_total_mem = 0; 

/* internal working copy of mallinfo */
STATIC struct mallinfo current_mallinfo = {  0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

#if HAVE_MMAP

/* Tracking mmaps */

STATIC unsigned int n_mmaps = 0;
STATIC unsigned int max_n_mmaps = 0;
STATIC unsigned long mmapped_mem = 0;
STATIC unsigned long max_mmapped_mem = 0;

#endif

#else /* ! DEFINE_MALLOC */

extern unsigned long trim_threshold;
extern unsigned long top_pad;
#if HAVE_MMAP
extern unsigned int  n_mmaps_max;
extern unsigned long mmap_threshold;
#endif
extern char* sbrk_base;
extern unsigned long max_sbrked_mem;
extern unsigned long max_total_mem;
extern struct mallinfo current_mallinfo;
#if HAVE_MMAP
extern unsigned int n_mmaps;
extern unsigned int max_n_mmaps;
extern unsigned long mmapped_mem;
extern unsigned long max_mmapped_mem;
#endif

#endif /* ! DEFINE_MALLOC */

/* The total memory obtained from system via sbrk */
#define sbrked_mem  (current_mallinfo.arena)



/* 
  Debugging support 
*/

#if DEBUG


/*
  These routines make a number of assertions about the states
  of data structures that should be true at all times. If any
  are not true, it's very likely that a user program has somehow
  trashed memory. (It's also possible that there is a coding error
  in malloc. In which case, please report it!)
*/

#if __STD_C
static void do_check_chunk(mchunkptr p) 
#else
static void do_check_chunk(p) mchunkptr p;
#endif
{ 
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;

  /* No checkable chunk is mmapped */
  assert(!chunk_is_mmapped(p));

  /* Check for legal address ... */
  assert((char*)p >= sbrk_base);
  if (p != top) 
    assert((char*)p + sz <= (char*)top);
  else
    assert((char*)p + sz <= sbrk_base + sbrked_mem);

}


#if __STD_C
static void do_check_free_chunk(mchunkptr p) 
#else
static void do_check_free_chunk(p) mchunkptr p;
#endif
{ 
  INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE;
  mchunkptr next = chunk_at_offset(p, sz);

  do_check_chunk(p);

  /* Check whether it claims to be free ... */
  assert(!inuse(p));

  /* Unless a special marker, must have OK fields */
  if ((long)sz >= (long)MINSIZE)
  {
    assert((sz & MALLOC_ALIGN_MASK) == 0);
    assert(aligned_OK(chunk2mem(p)));
    /* ... matching footer field */
    assert(next->prev_size == sz);
    /* ... and is fully consolidated */
    assert(prev_inuse(p));
    assert (next == top || inuse(next));
    
    /* ... and has minimally sane links */
    assert(p->fd->bk == p);
    assert(p->bk->fd == p);
  }
  else /* markers are always of size SIZE_SZ */
    assert(sz == SIZE_SZ); 
}

#if __STD_C
static void do_check_inuse_chunk(mchunkptr p) 
#else
static void do_check_inuse_chunk(p) mchunkptr p;
#endif
{ 
  mchunkptr next = next_chunk(p);
  do_check_