boehm-gc/include/gc_inl.h

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
   4  *
   5  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   6  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   7  *
   8  * Permission is hereby granted to use or copy this program
   9  * for any purpose,  provided the above notices are retained on all copies.
  10  * Permission to modify the code and to distribute modified code is granted,
  11  * provided the above notices are retained, and a notice that the code was
  12  * modified is included with the above copyright notice.
  13  */
  14 /* Boehm, October 3, 1995 2:07 pm PDT */
  15
  16 # ifndef GC_PRIVATE_H
  17 #   include "private/gc_priv.h"
  18 # endif
  19
  20 /* USE OF THIS FILE IS NOT RECOMMENDED unless GC_all_interior_pointers  */
  21 /* is always set, or the collector has been built with                  */
  22 /* -DDONT_ADD_BYTE_AT_END, or the specified size includes a pointerfree */
  23 /* word at the end.  In the standard collector configuration,           */
  24 /* the final word of each object may not be scanned.                    */
  25 /* This iinterface is most useful for compilers that generate C.        */
  26 /* Manual use is hereby discouraged.                                    */
  27
  28 /* Allocate n words (NOT BYTES).  X is made to point to the result.     */
  29 /* It is assumed that n < MAXOBJSZ, and                                 */
  30 /* that n > 0.  On machines requiring double word alignment of some     */
  31 /* data, we also assume that n is 1 or even.                            */
  32 /* If the collector is built with -DUSE_MARK_BYTES or -DPARALLEL_MARK,  */
  33 /* the n = 1 case is also disallowed.                                   */
  34 /* Effectively this means that portable code should make sure n is even.*/
  35 /* This bypasses the                                                    */
  36 /* MERGE_SIZES mechanism.  In order to minimize the number of distinct  */
  37 /* free lists that are maintained, the caller should ensure that a      */
  38 /* small number of distinct values of n are used.  (The MERGE_SIZES     */
  39 /* mechanism normally does this by ensuring that only the leading three */
  40 /* bits of n may be nonzero.  See misc.c for details.)  We really       */
  41 /* recommend this only in cases in which n is a constant, and no        */
  42 /* locking is required.                                                 */
  43 /* In that case it may allow the compiler to perform substantial        */
  44 /* additional optimizations.                                            */
  45 # define GC_MALLOC_WORDS(result,n) \
  46 {       \
  47     register ptr_t op;  \
  48     register ptr_t *opp;        \
  49     DCL_LOCK_STATE;     \
  50         \
  51     opp = &(GC_objfreelist[n]); \
  52     FASTLOCK(); \
  53     if( !FASTLOCK_SUCCEEDED() || (op = *opp) == 0 ) {   \
  54         FASTUNLOCK();   \
  55         (result) = GC_generic_malloc_words_small((n), NORMAL);  \
  56     } else {    \
  57         *opp = obj_link(op);    \
  58         obj_link(op) = 0;       \
  59         GC_words_allocd += (n); \
  60         FASTUNLOCK();   \
  61         (result) = (GC_PTR) op; \
  62     }   \
  63 }
  64
  65
  66 /* The same for atomic objects: */
  67 # define GC_MALLOC_ATOMIC_WORDS(result,n) \
  68 {       \
  69     register ptr_t op;  \
  70     register ptr_t *opp;        \
  71     DCL_LOCK_STATE;     \
  72         \
  73     opp = &(GC_aobjfreelist[n]);        \
  74     FASTLOCK(); \
  75     if( !FASTLOCK_SUCCEEDED() || (op = *opp) == 0 ) {   \
  76         FASTUNLOCK();   \
  77         (result) = GC_generic_malloc_words_small((n), PTRFREE); \
  78     } else {    \
  79         *opp = obj_link(op);    \
  80         obj_link(op) = 0;       \
  81         GC_words_allocd += (n); \
  82         FASTUNLOCK();   \
  83         (result) = (GC_PTR) op; \
  84     }   \
  85 }
  86
  87 /* And once more for two word initialized objects: */
  88 # define GC_CONS(result, first, second) \
  89 {       \
  90     register ptr_t op;  \
  91     register ptr_t *opp;        \
  92     DCL_LOCK_STATE;     \
  93         \
  94     opp = &(GC_objfreelist[2]); \
  95     FASTLOCK(); \
  96     if( !FASTLOCK_SUCCEEDED() || (op = *opp) == 0 ) {   \
  97         FASTUNLOCK();   \
  98         op = GC_generic_malloc_words_small(2, NORMAL);  \
  99     } else {    \
 100         *opp = obj_link(op);    \
 101         GC_words_allocd += 2;   \
 102         FASTUNLOCK();   \
 103     } \
 104     ((word *)op)[0] = (word)(first);    \
 105     ((word *)op)[1] = (word)(second);   \
 106     (result) = (GC_PTR) op;     \
 107 }