libgc/include/gc_gcj.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 1996-1999 by Silicon Graphics.  All rights reserved.
   5  * Copyright 1999 by Hewlett-Packard Company.  All rights reserved.
   6  *
   7  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   8  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   9  *
  10  * Permission is hereby granted to use or copy this program
  11  * for any purpose,  provided the above notices are retained on all copies.
  12  * Permission to modify the code and to distribute modified code is granted,
  13  * provided the above notices are retained, and a notice that the code was
  14  * modified is included with the above copyright notice.
  15  */
  16
  17 /* This file assumes the collector has been compiled with GC_GCJ_SUPPORT */
  18 /* and that an ANSI C compiler is available.                             */
  19
  20 /*
  21  * We allocate objects whose first word contains a pointer to a struct
  22  * describing the object type.  This struct contains a garbage collector mark
  23  * descriptor at offset MARK_DESCR_OFFSET.  Alternatively, the objects
  24  * may be marked by the mark procedure passed to GC_init_gcj_malloc.
  25  */
  26
  27 #ifndef GC_GCJ_H
  28
  29 #define GC_GCJ_H
  30
  31 #ifndef MARK_DESCR_OFFSET
  32 #  define MARK_DESCR_OFFSET     sizeof(word)
  33 #endif
  34         /* Gcj keeps GC descriptor as second word of vtable.    This    */
  35         /* probably needs to be adjusted for other clients.             */
  36         /* We currently assume that this offset is such that:           */
  37         /*      - all objects of this kind are large enough to have     */
  38         /*        a value at that offset, and                           */
  39         /*      - it is not zero.                                       */
  40         /* These assumptions allow objects on the free list to be       */
  41         /* marked normally.                                             */
  42
  43 #ifndef _GC_H
  44 #   include "gc.h"
  45 #endif
  46
  47 /* The following allocators signal an out of memory condition with      */
  48 /* return GC_oom_fn(bytes);                                             */
  49
  50 /* The following function must be called before the gcj allocators      */
  51 /* can be invoked.                                                      */
  52 /* mp_index and mp are the index and mark_proc (see gc_mark.h)          */
  53 /* respectively for the allocated objects.  Mark_proc will be           */
  54 /* used to build the descriptor for objects allocated through the       */
  55 /* debugging interface.  The mark_proc will be invoked on all such      */
  56 /* objects with an "environment" value of 1.  The client may choose     */
  57 /* to use the same mark_proc for some of its generated mark descriptors.*/
  58 /* In that case, it should use a different "environment" value to       */
  59 /* detect the presence or absence of the debug header.                  */
  60 /* Mp is really of type mark_proc, as defined in gc_mark.h.  We don't   */
  61 /* want to include that here for namespace pollution reasons.           */
  62 extern void GC_init_gcj_malloc(int mp_index, void * /* really mark_proc */mp);
  63
  64 /* Allocate an object, clear it, and store the pointer to the   */
  65 /* type structure (vtable in gcj).                              */
  66 /* This adds a byte at the end of the object if GC_malloc would.*/
  67 extern void * GC_gcj_malloc(size_t lb, void * ptr_to_struct_containing_descr);
  68 /* The debug versions allocate such that the specified mark_proc        */
  69 /* is always invoked.                                                   */
  70 extern void * GC_debug_gcj_malloc(size_t lb,
  71                                   void * ptr_to_struct_containing_descr,
  72                                   GC_EXTRA_PARAMS);
  73
  74 /* Similar to the above, but the size is in words, and we don't */
  75 /* adjust it.  The size is assumed to be such that it can be    */
  76 /* allocated as a small object.                                 */
  77 /* Unless it is known that the collector is not configured      */
  78 /* with USE_MARK_BYTES and unless it is known that the object   */
  79 /* has weak alignment requirements, lw must be even.            */
  80 extern void * GC_gcj_fast_malloc(size_t lw,
  81                                  void * ptr_to_struct_containing_descr);
  82 extern void * GC_debug_gcj_fast_malloc(size_t lw,
  83                                  void * ptr_to_struct_containing_descr,
  84                                  GC_EXTRA_PARAMS);
  85
  86 /* Similar to GC_gcj_malloc, but assumes that a pointer to near the     */
  87 /* beginning of the resulting object is always maintained.              */
  88 extern void * GC_gcj_malloc_ignore_off_page(size_t lb,
  89                                 void * ptr_to_struct_containing_descr);
  90
  91 /* The kind numbers of normal and debug gcj objects.            */
  92 /* Useful only for debug support, we hope.                      */
  93 extern int GC_gcj_kind;
  94
  95 extern int GC_gcj_debug_kind;
  96
  97 # if defined(GC_LOCAL_ALLOC_H) && defined(GC_REDIRECT_TO_LOCAL)
  98     --> gc_local_alloc.h should be included after this.  Otherwise
  99     --> we undo the redirection.
 100 # endif
 101
 102 # ifdef GC_DEBUG
 103 #   define GC_GCJ_MALLOC(s,d) GC_debug_gcj_malloc(s,d,GC_EXTRAS)
 104 #   define GC_GCJ_FAST_MALLOC(s,d) GC_debug_gcj_fast_malloc(s,d,GC_EXTRAS)
 105 #   define GC_GCJ_MALLOC_IGNORE_OFF_PAGE(s,d) GC_debug_gcj_malloc(s,d,GC_EXTRAS)
 106 # else
 107 #   define GC_GCJ_MALLOC(s,d) GC_gcj_malloc(s,d)
 108 #   define GC_GCJ_FAST_MALLOC(s,d) GC_gcj_fast_malloc(s,d)
 109 #   define GC_GCJ_MALLOC_IGNORE_OFF_PAGE(s,d) \
 110         GC_gcj_malloc_ignore_off_page(s,d)
 111 # endif
 112
 113 #endif /* GC_GCJ_H */