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 #include "libguile/hooks.h"
  53
  54 \f
  55
  56 typedef struct scm_cell
  57 {
  58   scm_bits_t word_0;
  59   scm_bits_t word_1;
  60 } scm_cell;
  61
  62
  63 /* SCM_CELLPTR is a pointer to a cons cell which may be compared or
  64  * differenced.
  65  */
  66 typedef scm_cell * SCM_CELLPTR;
  67
  68
  69 /* Cray machines have pointers that are incremented once for each word,
  70  * rather than each byte, the 3 most significant bits encode the byte
  71  * within the word.  The following macros deal with this by storing the
  72  * native Cray pointers like the ones that looks like scm expects.  This
  73  * is done for any pointers that might appear in the car of a scm_cell,
  74  *  pointers to scm_vector elts, functions, &c are not munged.
  75  */
  76 #ifdef _UNICOS
  77     #define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x) >> 3))
  78     #define PTR2SCM(x) (SCM_PACK (((scm_bits_t) (x)) << 3))
  79 #else
  80     #define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x)))
  81     #define PTR2SCM(x) (SCM_PACK ((scm_bits_t) (x)))
  82 #endif /* def _UNICOS */
  83
  84
  85 /* Low level cell data accessing macros:
  86  */
  87
  88 #define SCM_CELL_WORD(x, n) (((scm_bits_t *) SCM2PTR (x)) [n])
  89 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
  90 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
  91 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
  92 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
  93
  94 #define SCM_CELL_OBJECT(x, n) (SCM_PACK (((scm_bits_t *) SCM2PTR (x)) [n]))
  95 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
  96 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
  97 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
  98 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
  99
 100 #define SCM_SET_CELL_WORD(x, n, v) ((((scm_bits_t *) SCM2PTR (x)) [n]) = (scm_bits_t) (v))
 101 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 102 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 103 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 104 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 105
 106 #define SCM_SET_CELL_OBJECT(x, n, v) ((((scm_bits_t *) SCM2PTR (x)) [n]) = SCM_UNPACK (v))
 107 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 108 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 109 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 110 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 111
 112 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 113 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 114
 115 #define SCM_SETAND_CAR(x, y) \
 116   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) & (y))))
 117 #define SCM_SETAND_CDR(x, y)\
 118   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) & (y))))
 119 #define SCM_SETOR_CAR(x, y)\
 120   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) | (y))))
 121 #define SCM_SETOR_CDR(x, y)\
 122   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) | (y))))
 123
 124 #define SCM_CELL_WORD_LOC(x, n) (&SCM_CELL_WORD (x, n))
 125 #define SCM_CARLOC(x) (&SCM_CAR (x))
 126 #define SCM_CDRLOC(x) (&SCM_CDR (x))
 127
 128
 129 /* SCM_PTR_LT defines how to compare two SCM_CELLPTRs (which may not be in the
 130  * same scm_array).
 131  */
 132
 133 #ifdef nosve
 134     #define SCM_PTR_MASK      0xffffffffffff
 135     #define SCM_PTR_LT(x, y)  (((int) (x) & SCM_PTR_MASK) < ((int) (y) & SCM_PTR_MASK))
 136 #else
 137     #define SCM_PTR_LT(x, y)  ((x) < (y))
 138 #endif /* def nosve */
 139
 140 #define SCM_PTR_GT(x, y) SCM_PTR_LT (y, x)
 141 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 142 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 143
 144
 145 /* Dirk:FIXME:: */
 146 /* Freelists consist of linked cells where the type entry holds the value
 147  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 148  * the freelist.  Due to this structure, freelist cells are not cons cells
 149  * and thus may not be accessed using SCM_CAR and SCM_CDR.
 150  */
 151
 152 /* the allocated thing:  The car of new cells is set to
 153    scm_tc16_allocated to avoid the fragile state of newcells wrt the
 154    gc.  If it stays as a freecell, any allocation afterwards could
 155    cause the cell to go back on the freelist, which will bite you
 156    sometime afterwards. */
 157
 158 #ifdef GUILE_DEBUG_FREELIST
 159 #define SCM_NEWCELL(_into) do { _into = scm_debug_newcell (); } while (0)
 160 #define SCM_NEWCELL2(_into) do { _into = scm_debug_newcell2 (); } while (0)
 161 #else
 162 #ifdef GUILE_NEW_GC_SCHEME
 163 /* When we introduce POSIX threads support, every thread will have
 164    a freelist of its own.  Then it won't any longer be necessary to
 165    initialize cells with scm_tc16_allocated.  */
 166 #define SCM_NEWCELL(_into) \
 167         do { \
 168           if (SCM_IMP (scm_freelist)) \
 169              _into = scm_gc_for_newcell (&scm_master_freelist, \
 170                                          &scm_freelist); \
 171           else \
 172             { \
 173                _into = scm_freelist; \
 174                scm_freelist = SCM_CDR (scm_freelist); \
 175                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 176             } \
 177         } while(0)
 178 #define SCM_NEWCELL2(_into) \
 179         do { \
 180           if (SCM_IMP (scm_freelist2)) \
 181              _into = scm_gc_for_newcell (&scm_master_freelist2, \
 182                                          &scm_freelist2); \
 183           else \
 184             { \
 185                _into = scm_freelist2; \
 186                scm_freelist2 = SCM_CDR (scm_freelist2); \
 187                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 188             } \
 189         } while(0)
 190 #else /* GUILE_NEW_GC_SCHEME */
 191 #define SCM_NEWCELL(_into) \
 192         do { \
 193           if (SCM_IMP (scm_freelist.cells)) \
 194              _into = scm_gc_for_newcell (&scm_freelist); \
 195           else \
 196             { \
 197                _into = scm_freelist.cells; \
 198                scm_freelist.cells = SCM_CDR (scm_freelist.cells); \
 199                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 200                ++scm_cells_allocated; \
 201             } \
 202         } while(0)
 203 #define SCM_NEWCELL2(_into) \
 204         do { \
 205           if (SCM_IMP (scm_freelist2.cells)) \
 206              _into = scm_gc_for_newcell (&scm_freelist2); \
 207           else \
 208             { \
 209                _into = scm_freelist2.cells; \
 210                scm_freelist2.cells = SCM_CDR (scm_freelist2.cells); \
 211                SCM_SET_CELL_TYPE (_into, scm_tc16_allocated); \
 212                scm_cells_allocated += 2; \
 213             } \
 214         } while(0)
 215 #endif /* GUILE_NEW_GC_SCHEME */
 216 #endif
 217
 218
 219 #define SCM_FREEP(x) (SCM_NIMP (x) && (SCM_CELL_TYPE (x) == scm_tc_free_cell))
 220 #define SCM_NFREEP(x) (!SCM_FREEP (x))
 221
 222 /* 1. This shouldn't be used on immediates.
 223    2. It thinks that subrs are always unmarked (harmless). */
 224 #define SCM_MARKEDP(x) ((SCM_CELL_TYPE (x) & 5) == 5 \
 225                         ? SCM_GC8MARKP (x) \
 226                         : SCM_GCMARKP (x))
 227 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 228
 229 extern struct scm_heap_seg_data_t *scm_heap_table;
 230 extern int scm_n_heap_segs;
 231 extern int scm_take_stdin;
 232 extern int scm_block_gc;
 233 extern int scm_gc_heap_lock;
 234 \f
 235
 236 extern scm_sizet scm_max_segment_size;
 237 extern SCM_CELLPTR scm_heap_org;
 238 #ifdef GUILE_NEW_GC_SCHEME
 239 extern SCM scm_freelist;
 240 extern struct scm_freelist_t scm_master_freelist;
 241 extern SCM scm_freelist2;
 242 extern struct scm_freelist_t scm_master_freelist2;
 243 #else
 244 extern struct scm_freelist_t scm_freelist;
 245 extern struct scm_freelist_t scm_freelist2;
 246 #endif
 247 extern unsigned long scm_gc_cells_collected;
 248 #ifdef GUILE_NEW_GC_SCHEME
 249 extern unsigned long scm_gc_yield;
 250 #endif
 251 extern unsigned long scm_gc_malloc_collected;
 252 extern unsigned long scm_gc_ports_collected;
 253 extern unsigned long scm_cells_allocated;
 254 extern long scm_mallocated;
 255 extern unsigned long scm_mtrigger;
 256
 257 extern SCM scm_after_gc_hook;
 258
 259 extern scm_c_hook_t scm_before_gc_c_hook;
 260 extern scm_c_hook_t scm_before_mark_c_hook;
 261 extern scm_c_hook_t scm_before_sweep_c_hook;
 262 extern scm_c_hook_t scm_after_sweep_c_hook;
 263 extern scm_c_hook_t scm_after_gc_c_hook;
 264
 265 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 266 extern SCM scm_map_free_list (void);
 267 extern SCM scm_free_list_length (void);
 268 #endif
 269 #ifdef GUILE_DEBUG_FREELIST
 270 extern SCM scm_debug_newcell (void);
 271 extern SCM scm_debug_newcell2 (void);
 272 extern SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 273 #endif
 274
 275 \f
 276
 277 extern SCM scm_object_address (SCM obj);
 278 extern SCM scm_unhash_name (SCM name);
 279 extern SCM scm_gc_stats (void);
 280 extern void scm_gc_start (const char *what);
 281 extern void scm_gc_end (void);
 282 extern SCM scm_gc (void);
 283 extern void scm_gc_for_alloc (struct scm_freelist_t *freelist);
 284 #ifdef GUILE_NEW_GC_SCHEME
 285 extern SCM scm_gc_for_newcell (struct scm_freelist_t *master, SCM *freelist);
 286 #if 0
 287 extern void scm_alloc_cluster (struct scm_freelist_t *master);
 288 #endif
 289 #else
 290 extern SCM scm_gc_for_newcell (struct scm_freelist_t *freelist);
 291 #endif
 292 extern void scm_igc (const char *what);
 293 extern void scm_gc_mark (SCM p);
 294 extern void scm_mark_locations (SCM_STACKITEM x[], scm_sizet n);
 295 extern int scm_cellp (SCM value);
 296 extern void scm_gc_sweep (void);
 297 extern void * scm_must_malloc (scm_sizet len, const char *what);
 298 extern void * scm_must_realloc (void *where,
 299                                 scm_sizet olen, scm_sizet len,
 300                                 const char *what);
 301 extern void scm_done_malloc (long size);
 302 extern void scm_must_free (void *obj);
 303 extern void scm_remember (SCM * ptr);
 304 extern SCM scm_return_first (SCM elt, ...);
 305 extern int scm_return_first_int (int x, ...);
 306 extern SCM scm_permanent_object (SCM obj);
 307 extern SCM scm_protect_object (SCM obj);
 308 extern SCM scm_unprotect_object (SCM obj);
 309 #ifdef GUILE_NEW_GC_SCHEME
 310 extern int scm_init_storage (scm_sizet init_heap_size, int trig,
 311                              scm_sizet init_heap2_size, int trig2,
 312                              scm_sizet max_segment_size);
 313 #else
 314 extern int scm_init_storage (scm_sizet init_heap_size,
 315                              scm_sizet init_heap2_size);
 316 #endif
 317 extern void scm_init_gc (void);
 318 #endif  /* GCH */
 319
 320 /*
 321   Local Variables:
 322   c-file-style: "gnu"
 323   End:
 324 */