malloc.c

俄罗斯高人Mamaich的Pocket gcc编译器（运行在PocketPC上）的全部源代码。

/* bin<->block macros */

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




/* Static bookkeeping data */

/* Helper macro to initialize bins */
#define IAV(i) _bin_at(&main_arena, i), _bin_at(&main_arena, i)

static arena main_arena = {
    {
 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)
    },
    &main_arena, /* next */
    0, /* size */
#if THREAD_STATS
    0, 0, 0, /* stat_lock_direct, stat_lock_loop, stat_lock_wait */
#endif
    MUTEX_INITIALIZER /* mutex */
};

#undef IAV

/* Thread specific data */

static tsd_key_t arena_key;
static mutex_t list_lock = MUTEX_INITIALIZER;

#if THREAD_STATS
static int stat_n_heaps;
#define THREAD_STAT(x) x
#else
#define THREAD_STAT(x) do ; while(0)
#endif

/* variables holding tunable values */

static unsigned long trim_threshold   = DEFAULT_TRIM_THRESHOLD;
static unsigned long top_pad          = DEFAULT_TOP_PAD;
static unsigned int  n_mmaps_max      = DEFAULT_MMAP_MAX;
static unsigned long mmap_threshold   = DEFAULT_MMAP_THRESHOLD;
static int           check_action     = DEFAULT_CHECK_ACTION;

/* 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;

/* The maximum via either sbrk or mmap (too difficult to track with threads) */
#ifdef NO_THREADS
static unsigned long max_total_mem;
#endif

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

/* Tracking mmaps */

static unsigned int n_mmaps;
static unsigned int max_n_mmaps;
static unsigned long mmapped_mem;
static unsigned long max_mmapped_mem;

/* Mapped memory in non-main arenas (reliable only for NO_THREADS). */
static unsigned long arena_mem;



#ifndef _LIBC
#define weak_variable
#else
/* In GNU libc we want the hook variables to be weak definitions to
   avoid a problem with Emacs.  */
#define weak_variable weak_function
#endif

/* Already initialized? */
int __malloc_initialized = -1;


#ifndef NO_THREADS

/* Magic value for the thread-specific arena pointer when
   malloc_atfork() is in use.  */

#define ATFORK_ARENA_PTR ((Void_t*)-1)

/* The following two functions are registered via thread_atfork() to
   make sure that the mutexes remain in a consistent state in the
   fork()ed version of a thread.  Also adapt the malloc and free hooks
   temporarily, because the `atfork' handler mechanism may use
   malloc/free internally (e.g. in LinuxThreads). */

#if defined _LIBC || defined MALLOC_HOOKS
static __malloc_ptr_t (*save_malloc_hook) __MALLOC_P ((size_t __size,
						       const __malloc_ptr_t));
static void           (*save_free_hook) __MALLOC_P ((__malloc_ptr_t __ptr,
						     const __malloc_ptr_t));
static Void_t*        save_arena;
#endif

static void
ptmalloc_lock_all __MALLOC_P((void))
{
  arena *ar_ptr;

  (void)mutex_lock(&list_lock);
  for(ar_ptr = &main_arena;;) {
    (void)mutex_lock(&ar_ptr->mutex);
    ar_ptr = ar_ptr->next;
    if(ar_ptr == &main_arena) break;
  }
#if defined _LIBC || defined MALLOC_HOOKS
  save_malloc_hook = __malloc_hook;
  save_free_hook = __free_hook;
  __malloc_hook = malloc_atfork;
  __free_hook = free_atfork;
  /* Only the current thread may perform malloc/free calls now. */
  tsd_getspecific(arena_key, save_arena);
  tsd_setspecific(arena_key, ATFORK_ARENA_PTR);
#endif
}

static void
ptmalloc_unlock_all __MALLOC_P((void))
{
  arena *ar_ptr;

#if defined _LIBC || defined MALLOC_HOOKS
  tsd_setspecific(arena_key, save_arena);
  __malloc_hook = save_malloc_hook;
  __free_hook = save_free_hook;
#endif
  for(ar_ptr = &main_arena;;) {
    (void)mutex_unlock(&ar_ptr->mutex);
    ar_ptr = ar_ptr->next;
    if(ar_ptr == &main_arena) break;
  }
  (void)mutex_unlock(&list_lock);
}

static void
ptmalloc_init_all __MALLOC_P((void))
{
  arena *ar_ptr;

#if defined _LIBC || defined MALLOC_HOOKS
  tsd_setspecific(arena_key, save_arena);
  __malloc_hook = save_malloc_hook;
  __free_hook = save_free_hook;
#endif
  for(ar_ptr = &main_arena;;) {
    (void)mutex_init(&ar_ptr->mutex);
    ar_ptr = ar_ptr->next;
    if(ar_ptr == &main_arena) break;
  }
  (void)mutex_init(&list_lock);
}

#endif /* !defined NO_THREADS */

/* Initialization routine. */
#if defined(_LIBC)
#if 0
static void ptmalloc_init __MALLOC_P ((void)) __attribute__ ((constructor));
#endif

#ifdef _LIBC
#include <string.h>
extern char **environ;

static char *
internal_function
next_env_entry (char ***position)
{
  char **current = *position;
  char *result = NULL;

  while (*current != NULL)
    {
      if (__builtin_expect ((*current)[0] == 'M', 0)
	  && (*current)[1] == 'A'
	  && (*current)[2] == 'L'
	  && (*current)[3] == 'L'
	  && (*current)[4] == 'O'
	  && (*current)[5] == 'C'
	  && (*current)[6] == '_')
	{
	  result = &(*current)[7];

	  /* Save current position for next visit.  */
	  *position = ++current;

	  break;
	}

      ++current;
    }

  return result;
}
#endif

static void
ptmalloc_init __MALLOC_P((void))
#else
void
ptmalloc_init __MALLOC_P((void))
#endif
{
#if defined _LIBC || defined MALLOC_HOOKS
# if __STD_C
  const char* s;
# else
  char* s;
# endif
#endif
  int secure;

  if(__malloc_initialized >= 0) return;
  __malloc_initialized = 0;
#ifdef _LIBC
  __libc_pagesize = __getpagesize();
#endif
#ifndef NO_THREADS
#if defined _LIBC || defined MALLOC_HOOKS
  /* With some threads implementations, creating thread-specific data
     or initializing a mutex may call malloc() itself.  Provide a
     simple starter version (realloc() won't work). */
  save_malloc_hook = __malloc_hook;
  save_free_hook = __free_hook;
  __malloc_hook = malloc_starter;
  __free_hook = free_starter;
#endif
#ifdef _LIBC
  /* Initialize the pthreads interface. */
  if (__pthread_initialize != NULL)
    __pthread_initialize();
#endif
#endif /* !defined NO_THREADS */
  mutex_init(&main_arena.mutex);
  mutex_init(&list_lock);
  tsd_key_create(&arena_key, NULL);
  tsd_setspecific(arena_key, (Void_t *)&main_arena);
  thread_atfork(ptmalloc_lock_all, ptmalloc_unlock_all, ptmalloc_init_all);
#if defined _LIBC || defined MALLOC_HOOKS
#ifndef NO_THREADS
  __malloc_hook = save_malloc_hook;
  __free_hook = save_free_hook;
#endif
  secure = __libc_enable_secure;
#ifdef _LIBC
  s = NULL;
  if (environ != NULL)
    {
      char **runp = environ;
      char *envline;

      while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL, 0))
	{
	  size_t len = strcspn (envline, "=");

	  if (envline[len] != '=')
	    /* This is a "MALLOC_" variable at the end of the string
	       without a '=' character.  Ignore it since otherwise we
	       will access invalid memory below.  */
	    continue;

	  switch (len)
	    {
	    case 6:
	      if (memcmp (envline, "CHECK_", 6) == 0)
		s = &envline[7];
	      break;
	    case 8:
	      if (! secure && memcmp (envline, "TOP_PAD_", 8) == 0)
		mALLOPt(M_TOP_PAD, atoi(&envline[9]));
	      break;
	    case 9:
	      if (! secure && memcmp (envline, "MMAP_MAX_", 9) == 0)
		mALLOPt(M_MMAP_MAX, atoi(&envline[10]));
	      break;
	    case 15:
	      if (! secure)
		{
		  if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0)
		    mALLOPt(M_TRIM_THRESHOLD, atoi(&envline[16]));
		  else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0)
		    mALLOPt(M_MMAP_THRESHOLD, atoi(&envline[16]));
		}
	      break;
	    default:
	      break;
	    }
	}
    }
#else
  if (! secure)
    {
      if((s = getenv("MALLOC_TRIM_THRESHOLD_")))
	mALLOPt(M_TRIM_THRESHOLD, atoi(s));
      if((s = getenv("MALLOC_TOP_PAD_")))
	mALLOPt(M_TOP_PAD, atoi(s));
      if((s = getenv("MALLOC_MMAP_THRESHOLD_")))
	mALLOPt(M_MMAP_THRESHOLD, atoi(s));
      if((s = getenv("MALLOC_MMAP_MAX_")))
	mALLOPt(M_MMAP_MAX, atoi(s));
    }
  s = getenv("MALLOC_CHECK_");
#endif
  if(s) {
    if(s[0]) mALLOPt(M_CHECK_ACTION, (int)(s[0] - '0'));
    __malloc_check_init();
  }
  if(__malloc_initialize_hook != NULL)
    (*__malloc_initialize_hook)();
#endif
  __malloc_initialized = 1;
}

/* There are platforms (e.g. Hurd) with a link-time hook mechanism. */
#ifdef thread_atfork_static
thread_atfork_static(ptmalloc_lock_all, ptmalloc_unlock_all, \
                     ptmalloc_init_all)
#endif

#if defined _LIBC || defined MALLOC_HOOKS

/* Hooks for debugging versions.  The initial hooks just call the
   initialization routine, then do the normal work. */

static Void_t*
#if __STD_C
malloc_hook_ini(size_t sz, const __malloc_ptr_t caller)
#else
malloc_hook_ini(sz, caller)
     size_t sz; const __malloc_ptr_t caller;
#endif
{
  __malloc_hook = NULL;
  ptmalloc_init();
  return mALLOc(sz);
}

static Void_t*
#if __STD_C
realloc_hook_ini(Void_t* ptr, size_t sz, const __malloc_ptr_t caller)
#else
realloc_hook_ini(ptr, sz, caller)
     Void_t* ptr; size_t sz; const __malloc_ptr_t caller;
#endif
{
  __malloc_hook