boehm-gc/include/private/dbg_mlc.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) 1997 by Silicon Graphics.  All rights reserved.
   5  * Copyright (c) 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 /*
  18  * This is mostly an internal header file.  Typical clients should
  19  * not use it.  Clients that define their own object kinds with
  20  * debugging allocators will probably want to include this, however.
  21  * No attempt is made to keep the namespace clean.  This should not be
  22  * included from header files that are frequently included by clients.
  23  */
  24
  25 #ifndef _DBG_MLC_H
  26
  27 #define _DBG_MLC_H
  28
  29 # define I_HIDE_POINTERS
  30 # include "gc_priv.h"
  31 # ifdef KEEP_BACK_PTRS
  32 #   include "gc_backptr.h"
  33 # endif
  34
  35 #ifndef HIDE_POINTER
  36   /* Gc.h was previously included, and hence the I_HIDE_POINTERS        */
  37   /* definition had no effect.  Repeat the gc.h definitions here to     */
  38   /* get them anyway.                                                   */
  39     typedef GC_word GC_hidden_pointer;
  40 #   define HIDE_POINTER(p) (~(GC_hidden_pointer)(p))
  41 #   define REVEAL_POINTER(p) ((GC_PTR)(HIDE_POINTER(p)))
  42 #endif /* HIDE_POINTER */
  43
  44 # define START_FLAG ((word)0xfedcedcb)
  45 # define END_FLAG ((word)0xbcdecdef)
  46         /* Stored both one past the end of user object, and one before  */
  47         /* the end of the object as seen by the allocator.              */
  48
  49 # if defined(KEEP_BACK_PTRS) || defined(PRINT_BLACK_LIST) \
  50      || defined(MAKE_BACK_GRAPH)
  51     /* Pointer "source"s that aren't real locations.    */
  52     /* Used in oh_back_ptr fields and as "source"       */
  53     /* argument to some marking functions.              */
  54 #       define NOT_MARKED (ptr_t)(0)
  55 #       define MARKED_FOR_FINALIZATION (ptr_t)(2)
  56             /* Object was marked because it is finalizable.     */
  57 #       define MARKED_FROM_REGISTER (ptr_t)(4)
  58             /* Object was marked from a rgister.  Hence the     */
  59             /* source of the reference doesn't have an address. */
  60 # endif /* KEEP_BACK_PTRS || PRINT_BLACK_LIST */
  61
  62 /* Object header */
  63 typedef struct {
  64 #   if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
  65         /* We potentially keep two different kinds of back      */
  66         /* pointers.  KEEP_BACK_PTRS stores a single back       */
  67         /* pointer in each reachable object to allow reporting  */
  68         /* of why an object was retained.  MAKE_BACK_GRAPH      */
  69         /* builds a graph containing the inverse of all         */
  70         /* "points-to" edges including those involving          */
  71         /* objects that have just become unreachable. This      */
  72         /* allows detection of growing chains of unreachable    */
  73         /* objects.  It may be possible to eventually combine   */
  74         /* both, but for now we keep them separate.  Both       */
  75         /* kinds of back pointers are hidden using the          */
  76         /* following macros.  In both cases, the plain version  */
  77         /* is constrained to have an least significant bit of 1,*/
  78         /* to allow it to be distinguished from a free list     */
  79         /* link.  This means the plain version must have an     */
  80         /* lsb of 0.                                            */
  81         /* Note that blocks dropped by black-listing will       */
  82         /* also have the lsb clear once debugging has           */
  83         /* started.                                             */
  84         /* We're careful never to overwrite a value with lsb 0. */
  85 #       if ALIGNMENT == 1
  86           /* Fudge back pointer to be even.  */
  87 #         define HIDE_BACK_PTR(p) HIDE_POINTER(~1 & (GC_word)(p))
  88 #       else
  89 #         define HIDE_BACK_PTR(p) HIDE_POINTER(p)
  90 #       endif
  91
  92 #       ifdef KEEP_BACK_PTRS
  93           GC_hidden_pointer oh_back_ptr;
  94 #       endif
  95 #       ifdef MAKE_BACK_GRAPH
  96           GC_hidden_pointer oh_bg_ptr;
  97 #       endif
  98 #       if defined(ALIGN_DOUBLE) && \
  99             (defined(KEEP_BACK_PTRS) != defined(MAKE_BACK_GRAPH))
 100           word oh_dummy;
 101 #       endif
 102 #   endif
 103     GC_CONST char * oh_string;  /* object descriptor string     */
 104     word oh_int;                /* object descriptor integers   */
 105 #   ifdef NEED_CALLINFO
 106       struct callinfo oh_ci[NFRAMES];
 107 #   endif
 108 #   ifndef SHORT_DBG_HDRS
 109       word oh_sz;                       /* Original malloc arg.         */
 110       word oh_sf;                       /* start flag */
 111 #   endif /* SHORT_DBG_HDRS */
 112 } oh;
 113 /* The size of the above structure is assumed not to dealign things,    */
 114 /* and to be a multiple of the word length.                             */
 115
 116 #ifdef SHORT_DBG_HDRS
 117 #   define DEBUG_BYTES (sizeof (oh))
 118 #   define UNCOLLECTABLE_DEBUG_BYTES DEBUG_BYTES
 119 #else
 120     /* Add space for END_FLAG, but use any extra space that was already */
 121     /* added to catch off-the-end pointers.                             */
 122     /* For uncollectable objects, the extra byte is not added.          */
 123 #   define UNCOLLECTABLE_DEBUG_BYTES (sizeof (oh) + sizeof (word))
 124 #   define DEBUG_BYTES (UNCOLLECTABLE_DEBUG_BYTES - EXTRA_BYTES)
 125 #endif
 126 #define USR_PTR_FROM_BASE(p) ((ptr_t)(p) + sizeof(oh))
 127
 128 /* Round bytes to words without adding extra byte at end.       */
 129 #define SIMPLE_ROUNDED_UP_WORDS(n) BYTES_TO_WORDS((n) + WORDS_TO_BYTES(1) - 1)
 130
 131 /* ADD_CALL_CHAIN stores a (partial) call chain into an object  */
 132 /* header.  It may be called with or without the allocation     */
 133 /* lock.                                                        */
 134 /* PRINT_CALL_CHAIN prints the call chain stored in an object   */
 135 /* to stderr.  It requires that we do not hold the lock.        */
 136 #ifdef SAVE_CALL_CHAIN
 137 #   define ADD_CALL_CHAIN(base, ra) GC_save_callers(((oh *)(base)) -> oh_ci)
 138 #   define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
 139 #else
 140 # ifdef GC_ADD_CALLER
 141 #   define ADD_CALL_CHAIN(base, ra) ((oh *)(base)) -> oh_ci[0].ci_pc = (ra)
 142 #   define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
 143 # else
 144 #   define ADD_CALL_CHAIN(base, ra)
 145 #   define PRINT_CALL_CHAIN(base)
 146 # endif
 147 #endif
 148
 149 # ifdef GC_ADD_CALLER
 150 #   define OPT_RA ra,
 151 # else
 152 #   define OPT_RA
 153 # endif
 154
 155
 156 /* Check whether object with base pointer p has debugging info  */
 157 /* p is assumed to point to a legitimate object in our part     */
 158 /* of the heap.                                                 */
 159 #ifdef SHORT_DBG_HDRS
 160 # define GC_has_other_debug_info(p) TRUE
 161 #else
 162   GC_bool GC_has_other_debug_info(/* p */);
 163 #endif
 164
 165 #if defined(KEEP_BACK_PTRS) || defined(MAKE_BACK_GRAPH)
 166 # define GC_HAS_DEBUG_INFO(p) \
 167         ((*((word *)p) & 1) && GC_has_other_debug_info(p))
 168 #else
 169 # define GC_HAS_DEBUG_INFO(p) GC_has_other_debug_info(p)
 170 #endif
 171
 172 /* Store debugging info into p.  Return displaced pointer. */
 173 /* Assumes we don't hold allocation lock.                  */
 174 ptr_t GC_store_debug_info(/* p, sz, string, integer */);
 175
 176 #endif /* _DBG_MLC_H */