ceph/src/boost/tools/build/src/engine/boehm_gc/include/gc_inline.h

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
   4  * Copyright (c) 2005 Hewlett-Packard Development Company, L.P.
   5  *
   6  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   7  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   8  *
   9  * Permission is hereby granted to use or copy this program
  10  * for any purpose,  provided the above notices are retained on all copies.
  11  * Permission to modify the code and to distribute modified code is granted,
  12  * provided the above notices are retained, and a notice that the code was
  13  * modified is included with the above copyright notice.
  14  */
  15
  16 /* USE OF THIS FILE IS NOT RECOMMENDED unless GC_all_interior_pointers  */
  17 /* is not set, or the collector has been built with                     */
  18 /* -DDONT_ADD_BYTE_AT_END, or the specified size includes a pointerfree */
  19 /* word at the end.  In the standard collector configuration,           */
  20 /* the final word of each object may not be scanned.                    */
  21 /* This interface is most useful for compilers that generate C.         */
  22 /* It is also used internally for thread-local allocation, in which     */
  23 /* case, the size is suitably adjusted by the caller.                   */
  24 /* Manual use is hereby discouraged.                                    */
  25
  26 #include "gc.h"
  27 #include "gc_tiny_fl.h"
  28
  29 #if __GNUC__ >= 3
  30 # define GC_EXPECT(expr, outcome) __builtin_expect(expr,outcome)
  31   /* Equivalent to (expr), but predict that usually (expr)==outcome. */
  32 #else
  33 # define GC_EXPECT(expr, outcome) (expr)
  34 #endif /* __GNUC__ */
  35
  36 /* The ultimately general inline allocation macro.  Allocate an object  */
  37 /* of size bytes, putting the resulting pointer in result.  Tiny_fl is  */
  38 /* a "tiny" free list array, which will be used first, if the size      */
  39 /* is appropriate.  If bytes is too large, we allocate with             */
  40 /* default_expr instead.  If we need to refill the free list, we use    */
  41 /* GC_generic_malloc_many with the indicated kind.                      */
  42 /* Tiny_fl should be an array of GC_TINY_FREELISTS void * pointers.     */
  43 /* If num_direct is nonzero, and the individual free list pointers      */
  44 /* are initialized to (void *)1, then we allocate numdirect granules    */
  45 /* directly using gmalloc before putting multiple objects into the      */
  46 /* tiny_fl entry.  If num_direct is zero, then the free lists may also  */
  47 /* be initialized to (void *)0.                                         */
  48 /* We rely on much of this hopefully getting optimized away in the      */
  49 /* num_direct = 0 case.                                                 */
  50 /* Particularly if bytes is constant, this should generate a small      */
  51 /* amount of code.                                                      */
  52 # define GC_FAST_MALLOC_GRANS(result,granules,tiny_fl,num_direct,\
  53                               kind,default_expr,init) \
  54 { \
  55     if (GC_EXPECT(granules >= GC_TINY_FREELISTS,0)) { \
  56         result = default_expr; \
  57     } else { \
  58         void **my_fl = tiny_fl + granules; \
  59         void *my_entry=*my_fl; \
  60         void *next; \
  61  \
  62         while (GC_EXPECT((GC_word)my_entry \
  63                                 <= num_direct + GC_TINY_FREELISTS + 1, 0)) { \
  64             /* Entry contains counter or NULL */ \
  65             if ((GC_word)my_entry - 1 < num_direct) { \
  66                 /* Small counter value, not NULL */ \
  67                 *my_fl = (ptr_t)my_entry + granules + 1; \
  68                 result = default_expr; \
  69                 goto out; \
  70             } else { \
  71                 /* Large counter or NULL */ \
  72                 GC_generic_malloc_many(((granules) == 0? GC_GRANULE_BYTES : \
  73                                           RAW_BYTES_FROM_INDEX(granules)), \
  74                                        kind, my_fl); \
  75                 my_entry = *my_fl; \
  76                 if (my_entry == 0) { \
  77                     result = GC_oom_fn(bytes); \
  78                     goto out; \
  79                 } \
  80             } \
  81         } \
  82         next = *(void **)(my_entry); \
  83         result = (void *)my_entry; \
  84         *my_fl = next; \
  85         init; \
  86         PREFETCH_FOR_WRITE(next); \
  87         GC_ASSERT(GC_size(result) >= bytes + EXTRA_BYTES); \
  88         GC_ASSERT((kind) == PTRFREE || ((GC_word *)result)[1] == 0); \
  89       out: ; \
  90    } \
  91 }
  92
  93 # define GC_WORDS_TO_WHOLE_GRANULES(n) \
  94         GC_WORDS_TO_GRANULES((n) + GC_GRANULE_WORDS - 1)
  95
  96 /* Allocate n words (NOT BYTES).  X is made to point to the result.     */
  97 /* This should really only be used if GC_all_interior_pointers is       */
  98 /* not set, or DONT_ADD_BYTE_AT_END is set.  See above.                 */
  99 /* The semantics changed in version 7.0; we no longer lock, and         */
 100 /* the caller is responsible for supplying a cleared tiny_fl            */
 101 /* free list array.  For single-threaded applications, this may be      */
 102 /* a global array.                                                      */
 103 # define GC_MALLOC_WORDS(result,n,tiny_fl) \
 104 {       \
 105     size_t grans = WORDS_TO_WHOLE_GRANULES(n); \
 106     GC_FAST_MALLOC_GRANS(result, grans, tiny_fl, 0, \
 107                          NORMAL, GC_malloc(grans*GRANULE_BYTES), \
 108                          *(void **)result = 0); \
 109 }
 110
 111 # define GC_MALLOC_ATOMIC_WORDS(result,n,tiny_fl) \
 112 {       \
 113     size_t grans = WORDS_TO_WHOLE_GRANULES(n); \
 114     GC_FAST_MALLOC_GRANS(result, grans, tiny_fl, 0, \
 115                          PTRFREE, GC_malloc_atomic(grans*GRANULE_BYTES), \
 116                          /* no initialization */); \
 117 }
 118
 119
 120 /* And once more for two word initialized objects: */
 121 # define GC_CONS(result, first, second, tiny_fl) \
 122 {       \
 123     size_t grans = WORDS_TO_WHOLE_GRANULES(2); \
 124     GC_FAST_MALLOC_GRANS(result, grans, tiny_fl, 0, \
 125                          NORMAL, GC_malloc(grans*GRANULE_BYTES), \
 126                          *(void **)result = (void *)(first)); \
 127     ((void **)(result))[1] = (void *)(second);  \
 128 }