libguile/gc.h

   1 /* classes: h_files */
   2
   3 #ifndef GCH
   4 #define GCH
   5 /* Copyright (C) 1995, 96, 98, 99, 2000 Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this software; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307 USA
  21  *
  22  * As a special exception, the Free Software Foundation gives permission
  23  * for additional uses of the text contained in its release of GUILE.
  24  *
  25  * The exception is that, if you link the GUILE library with other files
  26  * to produce an executable, this does not by itself cause the
  27  * resulting executable to be covered by the GNU General Public License.
  28  * Your use of that executable is in no way restricted on account of
  29  * linking the GUILE library code into it.
  30  *
  31  * This exception does not however invalidate any other reasons why
  32  * the executable file might be covered by the GNU General Public License.
  33  *
  34  * This exception applies only to the code released by the
  35  * Free Software Foundation under the name GUILE.  If you copy
  36  * code from other Free Software Foundation releases into a copy of
  37  * GUILE, as the General Public License permits, the exception does
  38  * not apply to the code that you add in this way.  To avoid misleading
  39  * anyone as to the status of such modified files, you must delete
  40  * this exception notice from them.
  41  *
  42  * If you write modifications of your own for GUILE, it is your choice
  43  * whether to permit this exception to apply to your modifications.
  44  * If you do not wish that, delete this exception notice.  */
  45
  46 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  47    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  48 \f
  49
  50 #include "libguile/__scm.h"
  51
  52 \f
  53
  54 typedef struct scm_cell
  55 {
  56   SCM car;
  57   SCM cdr;
  58 } scm_cell;
  59
  60
  61 /* SCM_CELLPTR is a pointer to a cons cell which may be compared or
  62  * differenced.
  63  */
  64 #if !defined (__TURBOC__) || defined (__TOS__) || defined (PROT386)
  65     typedef scm_cell * SCM_CELLPTR;
  66 #else
  67     typedef scm_cell huge * SCM_CELLPTR;
  68 #endif
  69
  70
  71 /* Cray machines have pointers that are incremented once for each word,
  72  * rather than each byte, the 3 most significant bits encode the byte
  73  * within the word.  The following macros deal with this by storing the
  74  * native Cray pointers like the ones that looks like scm expects.  This
  75  * is done for any pointers that might appear in the car of a scm_cell,
  76  *  pointers to scm_vector elts, functions, &c are not munged.
  77  */
  78 #ifdef _UNICOS
  79     #define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x) >> 3))
  80     #define PTR2SCM(x) (SCM_PACK (((scm_bits_t) (x)) << 3))
  81 #else
  82     #define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x)))
  83     #define PTR2SCM(x) (SCM_PACK ((scm_bits_t) (x)))
  84 #endif /* def _UNICOS */
  85
  86
  87 /* Low level cell data accessing macros:
  88  */
  89
  90 #define SCM_CELL_WORD(x, n) (SCM_UNPACK (((SCM *) SCM2PTR (x))[n]))
  91 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
  92 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
  93 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
  94 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
  95
  96 #define SCM_CELL_OBJECT(x, n) (((SCM *) SCM2PTR (x))[n])
  97 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
  98 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
  99 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 100 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 101
 102 #define SCM_SET_CELL_WORD(x, n, v) ((((SCM *) SCM2PTR (x))[n]) = SCM_PACK (v))
 103 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 104 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 105 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 106 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 107
 108 #define SCM_SET_CELL_OBJECT(x, n, v) ((((SCM *) SCM2PTR (x))[n]) = v)
 109 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 110 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 111 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 112 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 113
 114 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 115 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 116
 117 #define SCM_SETAND_CAR(x, y)\
 118   (SCM_CAR (x) = SCM_PACK (SCM_UNPACK (SCM_CAR (x)) & (y)))
 119 #define SCM_SETAND_CDR(x, y)\
 120   (SCM_CDR (x) = SCM_PACK (SCM_UNPACK (SCM_CDR (x)) & (y)))
 121 #define SCM_SETOR_CAR(x, y)\
 122   (SCM_CAR (x) = SCM_PACK (SCM_UNPACK (SCM_CAR (x)) | (y)))
 123 #define SCM_SETOR_CDR(x, y)\
 124   (SCM_CDR (x) = SCM_PACK (SCM_UNPACK (SCM_CDR (x)) | (y)))
 125
 126 #define SCM_CELL_WORD_LOC(x, n) (&SCM_CELL_WORD (x, n))
 127 #define SCM_CARLOC(x) (&SCM_CAR (x))
 128 #define SCM_CDRLOC(x) (&SCM_CDR (x))
 129
 130
 131 /* SCM_PTR_LT defines how to compare two SCM_CELLPTRs (which may not be in the
 132  * same scm_array).
 133  */
 134
 135 #if !defined(__TURBOC__) || defined(__TOS__)
 136     #ifdef nosve
 137         #define SCM_PTR_MASK 0xffffffffffff
 138         #define SCM_PTR_LT(x, y)\
 139                     (((int) (x) & SCM_PTR_MASK) < ((int) (y) & SCM_PTR_MASK))
 140     #else
 141         #define SCM_PTR_LT(x, y) ((x) < (y))
 142     #endif /* def nosve */
 143 #else /* defined(__TURBOC__) && !defined(__TOS__) */
 144     #ifdef PROT386
 145         #define SCM_PTR_LT(x, y) (((long) (x)) < ((long) (y)))
 146     #else
 147         #define SCM_PTR_LT(x, y) ((x) < (y))
 148     #endif /* def PROT386 */
 149 #endif /*  defined(__TURBOC__) && !defined(__TOS__) */
 150
 151 #define SCM_PTR_GT(x, y) SCM_PTR_LT (y, x)
 152 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 153 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 154
 155
 156 /* Dirk:FIXME:: */
 157 /* Freelists consist of linked cells where the type entry holds the value
 158  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 159  * the freelist.  Due to this structure, freelist cells are not cons cells
 160  * and thus may not be accessed using SCM_CAR and SCM_CDR.
 161  */
 162
 163 /* the allocated thing:  The car of new cells is set to
 164    scm_tc16_allocated to avoid the fragile state of newcells wrt the
 165    gc.  If it stays as a freecell, any allocation afterwards could
 166    cause the cell to go back on the freelist, which will bite you
 167    sometime afterwards. */
 168
 169 #ifdef GUILE_DEBUG_FREELIST
 170 #define SCM_NEWCELL(_into) do { _into = scm_debug_newcell (); } while (0)
 171 #define SCM_NEWCELL2(_into) do { _into = scm_debug_newcell2 (); } while (0)
 172 #else
 173 #ifdef GUILE_NEW_GC_SCHEME
 174 /* When we introduce POSIX threads support, every thread will have
 175    a freelist of its own.  Then it won't any longer be necessary to
 176    initialize cells with scm_tc16_allocated.  */
 177 #define SCM_NEWCELL(_into) \
 178         do { \
 179           if (SCM_IMP (scm_freelist)) \
 180              _into = scm_gc_for_newcell (&scm_master_freelist, \
 181                                          &scm_freelist); \
 182           else \
 183             { \
 184                _into = scm_freelist; \
 185                scm_freelist = SCM_CDR (scm_freelist); \
 186                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 187             } \
 188         } while(0)
 189 #define SCM_NEWCELL2(_into) \
 190         do { \
 191           if (SCM_IMP (scm_freelist2)) \
 192              _into = scm_gc_for_newcell (&scm_master_freelist2, \
 193                                          &scm_freelist2); \
 194           else \
 195             { \
 196                _into = scm_freelist2; \
 197                scm_freelist2 = SCM_CDR (scm_freelist2); \
 198                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 199             } \
 200         } while(0)
 201 #else /* GUILE_NEW_GC_SCHEME */
 202 #define SCM_NEWCELL(_into) \
 203         do { \
 204           if (SCM_IMP (scm_freelist.cells)) \
 205              _into = scm_gc_for_newcell (&scm_freelist); \
 206           else \
 207             { \
 208                _into = scm_freelist.cells; \
 209                scm_freelist.cells = SCM_CDR (scm_freelist.cells); \
 210                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 211                ++scm_cells_allocated; \
 212             } \
 213         } while(0)
 214 #define SCM_NEWCELL2(_into) \
 215         do { \
 216           if (SCM_IMP (scm_freelist2.cells)) \
 217              _into = scm_gc_for_newcell (&scm_freelist2); \
 218           else \
 219             { \
 220                _into = scm_freelist2.cells; \
 221                scm_freelist2.cells = SCM_CDR (scm_freelist2.cells); \
 222                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 223                scm_cells_allocated += 2; \
 224             } \
 225         } while(0)
 226 #endif /* GUILE_NEW_GC_SCHEME */
 227 #endif
 228
 229
 230 #define SCM_FREEP(x) (SCM_NIMP (x) && (SCM_CELL_TYPE (x) == scm_tc_free_cell))
 231 #define SCM_NFREEP(x) (!SCM_FREEP (x))
 232
 233 /* 1. This shouldn't be used on immediates.
 234    2. It thinks that subrs are always unmarked (harmless). */
 235 #define SCM_MARKEDP(x) ((SCM_CELL_TYPE (x) & 5) == 5 \
 236                         ? SCM_GC8MARKP (x) \
 237                         : SCM_GCMARKP (x))
 238 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 239
 240 extern struct scm_heap_seg_data_t *scm_heap_table;
 241 extern int scm_n_heap_segs;
 242 extern int scm_take_stdin;
 243 extern int scm_block_gc;
 244 extern int scm_gc_heap_lock;
 245 \f
 246
 247 extern scm_sizet scm_max_segment_size;
 248 extern SCM_CELLPTR scm_heap_org;
 249 #ifdef GUILE_NEW_GC_SCHEME
 250 extern SCM scm_freelist;
 251 extern struct scm_freelist_t scm_master_freelist;
 252 extern SCM scm_freelist2;
 253 extern struct scm_freelist_t scm_master_freelist2;
 254 #else
 255 extern struct scm_freelist_t scm_freelist;
 256 extern struct scm_freelist_t scm_freelist2;
 257 #endif
 258 extern unsigned long scm_gc_cells_collected;
 259 #ifdef GUILE_NEW_GC_SCHEME
 260 extern unsigned long scm_gc_yield;
 261 #endif
 262 extern unsigned long scm_gc_malloc_collected;
 263 extern unsigned long scm_gc_ports_collected;
 264 extern unsigned long scm_cells_allocated;
 265 extern long scm_mallocated;
 266 extern unsigned long scm_mtrigger;
 267
 268 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 269 extern SCM scm_map_free_list (void);
 270 extern SCM scm_free_list_length (void);
 271 #endif
 272 #ifdef GUILE_DEBUG_FREELIST
 273 extern SCM scm_debug_newcell (void);
 274 extern SCM scm_debug_newcell2 (void);
 275 extern SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 276 #endif
 277
 278 \f
 279
 280 extern SCM scm_object_address (SCM obj);
 281 extern SCM scm_unhash_name (SCM name);
 282 extern SCM scm_gc_stats (void);
 283 extern void scm_gc_start (const char *what);
 284 extern void scm_gc_end (void);
 285 extern SCM scm_gc (void);
 286 extern void scm_gc_for_alloc (struct scm_freelist_t *freelist);
 287 #ifdef GUILE_NEW_GC_SCHEME
 288 extern SCM scm_gc_for_newcell (struct scm_freelist_t *master, SCM *freelist);
 289 #if 0
 290 extern void scm_alloc_cluster (struct scm_freelist_t *master);
 291 #endif
 292 #else
 293 extern SCM scm_gc_for_newcell (struct scm_freelist_t *freelist);
 294 #endif
 295 extern void scm_igc (const char *what);
 296 extern void scm_gc_mark (SCM p);
 297 extern void scm_mark_locations (SCM_STACKITEM x[], scm_sizet n);
 298 extern int scm_cellp (SCM value);
 299 extern void scm_gc_sweep (void);
 300 extern void * scm_must_malloc (scm_sizet len, const char *what);
 301 extern void * scm_must_realloc (void *where,
 302                                 scm_sizet olen, scm_sizet len,
 303                                 const char *what);
 304 extern void scm_done_malloc (long size);
 305 extern void scm_must_free (void *obj);
 306 extern void scm_remember (SCM * ptr);
 307 extern SCM scm_return_first (SCM elt, ...);
 308 extern int scm_return_first_int (int x, ...);
 309 extern SCM scm_permanent_object (SCM obj);
 310 extern SCM scm_protect_object (SCM obj);
 311 extern SCM scm_unprotect_object (SCM obj);
 312 #ifdef GUILE_NEW_GC_SCHEME
 313 extern int scm_init_storage (scm_sizet init_heap_size, int trig,
 314                              scm_sizet init_heap2_size, int trig2,
 315                              scm_sizet max_segment_size);
 316 #else
 317 extern int scm_init_storage (scm_sizet init_heap_size,
 318                              scm_sizet init_heap2_size);
 319 #endif
 320 extern void scm_init_gc (void);
 321 #endif  /* GCH */
 322
 323 /*
 324   Local Variables:
 325   c-file-style: "gnu"
 326   End:
 327 */