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 #if (SCM_DEBUG_CELL_ACCESSES == 1)
  89 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
  90 #else
  91 #  define SCM_VALIDATE_CELL(cell, expr) expr
  92 #endif
  93
  94 #define SCM_CELL_WORD(x, n) \
  95   SCM_VALIDATE_CELL ((x), ((const scm_bits_t *) SCM2PTR (x)) [n])
  96 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
  97 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
  98 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
  99 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 100
 101 #define SCM_CELL_OBJECT(x, n) \
 102   SCM_VALIDATE_CELL ((x), SCM_PACK (((const scm_bits_t *) SCM2PTR (x)) [n]))
 103 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 104 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 105 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 106 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 107
 108 #define SCM_SET_CELL_WORD(x, n, v) \
 109   SCM_VALIDATE_CELL ((x), ((scm_bits_t *) SCM2PTR (x)) [n] = (scm_bits_t) (v))
 110 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 111 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 112 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 113 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 114
 115 #define SCM_SET_CELL_OBJECT(x, n, v) \
 116   SCM_VALIDATE_CELL ((x), ((scm_bits_t *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 117 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 118 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 119 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 120 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 121
 122 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 123 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 124
 125 #define SCM_SETAND_CAR(x, y) \
 126   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) & (y))))
 127 #define SCM_SETAND_CDR(x, y)\
 128   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) & (y))))
 129 #define SCM_SETOR_CAR(x, y)\
 130   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) | (y))))
 131 #define SCM_SETOR_CDR(x, y)\
 132   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) | (y))))
 133
 134 #define SCM_CELL_WORD_LOC(x, n) ((scm_bits_t *) & SCM_CELL_WORD (x, n))
 135 #define SCM_CARLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 0))
 136 #define SCM_CDRLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 1))
 137
 138
 139 /* SCM_PTR_LT and friends define how to compare two SCM_CELLPTRs (which may
 140  * point to cells in different heap segments).
 141  */
 142 #define SCM_PTR_LT(x, y) ((x) < (y))
 143 #define SCM_PTR_GT(x, y) (SCM_PTR_LT (y, x))
 144 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 145 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 146
 147
 148 /* Freelists consist of linked cells where the type entry holds the value
 149  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 150  * the freelist.  Due to this structure, freelist cells are not cons cells
 151  * and thus may not be accessed using SCM_CAR and SCM_CDR.
 152  */
 153
 154 #define SCM_FREE_CELL_P(x) \
 155   (!SCM_IMP (x) && (* (const scm_bits_t *) SCM2PTR (x) == scm_tc_free_cell))
 156 #define SCM_FREE_CELL_CDR(x) \
 157   (((const scm_bits_t *) SCM2PTR (x)) [1])
 158 #define SCM_SET_FREE_CELL_TYPE(x, v) \
 159   (((scm_bits_t *) SCM2PTR (x)) [0] = (v))
 160 #define SCM_SET_FREE_CELL_CDR(x, v) \
 161   (((scm_bits_t *) SCM2PTR (x)) [1] = (v))
 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 /* When we introduce POSIX threads support, every thread will have
 174    a freelist of its own.  Then it won't any longer be necessary to
 175    initialize cells with scm_tc16_allocated.  */
 176 #define SCM_NEWCELL(_into) \
 177         do { \
 178           if (SCM_IMP (scm_freelist)) \
 179              _into = scm_gc_for_newcell (&scm_master_freelist, \
 180                                          &scm_freelist); \
 181           else \
 182             { \
 183                _into = scm_freelist; \
 184                scm_freelist = SCM_FREE_CELL_CDR (scm_freelist); \
 185                SCM_SET_FREE_CELL_TYPE (_into, scm_tc16_allocated); \
 186             } \
 187         } while(0)
 188 #define SCM_NEWCELL2(_into) \
 189         do { \
 190           if (SCM_IMP (scm_freelist2)) \
 191              _into = scm_gc_for_newcell (&scm_master_freelist2, \
 192                                          &scm_freelist2); \
 193           else \
 194             { \
 195                _into = scm_freelist2; \
 196                scm_freelist2 = SCM_FREE_CELL_CDR (scm_freelist2); \
 197                SCM_SET_FREE_CELL_TYPE (_into, scm_tc16_allocated); \
 198             } \
 199         } while(0)
 200 #endif
 201
 202
 203 #define SCM_FREEP(x) (SCM_FREE_CELL_P (x))
 204 #define SCM_NFREEP(x) (!SCM_FREEP (x))
 205
 206 /* 1. This shouldn't be used on immediates.
 207    2. It thinks that subrs are always unmarked (harmless). */
 208 #define SCM_MARKEDP(x) ((SCM_CELL_TYPE (x) & 5) == 5 \
 209                         ? SCM_GC8MARKP (x) \
 210                         : SCM_GCMARKP (x))
 211 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 212
 213 extern struct scm_heap_seg_data_t *scm_heap_table;
 214 extern int scm_n_heap_segs;
 215 extern int scm_block_gc;
 216 extern int scm_gc_heap_lock;
 217 extern unsigned int scm_gc_running_p;
 218 \f
 219
 220 extern int scm_default_init_heap_size_1;
 221 extern int scm_default_min_yield_1;
 222 extern int scm_default_init_heap_size_2;
 223 extern int scm_default_min_yield_2;
 224 extern int scm_default_max_segment_size;
 225
 226 extern scm_sizet scm_max_segment_size;
 227 extern SCM_CELLPTR scm_heap_org;
 228 extern SCM scm_freelist;
 229 extern struct scm_freelist_t scm_master_freelist;
 230 extern SCM scm_freelist2;
 231 extern struct scm_freelist_t scm_master_freelist2;
 232 extern unsigned long scm_gc_cells_collected;
 233 extern unsigned long scm_gc_yield;
 234 extern unsigned long scm_gc_malloc_collected;
 235 extern unsigned long scm_gc_ports_collected;
 236 extern unsigned long scm_cells_allocated;
 237 extern long scm_mallocated;
 238 extern unsigned long scm_mtrigger;
 239
 240 extern SCM scm_after_gc_hook;
 241
 242 extern scm_c_hook_t scm_before_gc_c_hook;
 243 extern scm_c_hook_t scm_before_mark_c_hook;
 244 extern scm_c_hook_t scm_before_sweep_c_hook;
 245 extern scm_c_hook_t scm_after_sweep_c_hook;
 246 extern scm_c_hook_t scm_after_gc_c_hook;
 247
 248 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 249 extern void scm_assert_cell_valid (SCM);
 250 extern unsigned int scm_debug_cell_accesses_p;
 251 extern SCM scm_set_debug_cell_accesses_x (SCM flag);
 252 #endif
 253
 254 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 255 extern SCM scm_map_free_list (void);
 256 extern SCM scm_free_list_length (void);
 257 #endif
 258 #ifdef GUILE_DEBUG_FREELIST
 259 extern SCM scm_debug_newcell (void);
 260 extern SCM scm_debug_newcell2 (void);
 261 extern SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 262 #endif
 263
 264 \f
 265
 266 extern SCM scm_object_address (SCM obj);
 267 extern SCM scm_unhash_name (SCM name);
 268 extern SCM scm_gc_stats (void);
 269 extern void scm_gc_start (const char *what);
 270 extern void scm_gc_end (void);
 271 extern SCM scm_gc (void);
 272 extern void scm_gc_for_alloc (struct scm_freelist_t *freelist);
 273 extern SCM scm_gc_for_newcell (struct scm_freelist_t *master, SCM *freelist);
 274 #if 0
 275 extern void scm_alloc_cluster (struct scm_freelist_t *master);
 276 #endif
 277 extern void scm_igc (const char *what);
 278 extern void scm_gc_mark (SCM p);
 279 extern void scm_mark_locations (SCM_STACKITEM x[], scm_sizet n);
 280 extern int scm_cellp (SCM value);
 281 extern void scm_gc_sweep (void);
 282 extern void * scm_must_malloc (scm_sizet len, const char *what);
 283 extern void * scm_must_realloc (void *where,
 284                                 scm_sizet olen, scm_sizet len,
 285                                 const char *what);
 286 extern void scm_done_malloc (long size);
 287 extern void scm_must_free (void *obj);
 288 extern void scm_remember (SCM * ptr);
 289 extern SCM scm_return_first (SCM elt, ...);
 290 extern int scm_return_first_int (int x, ...);
 291 extern SCM scm_permanent_object (SCM obj);
 292 extern SCM scm_protect_object (SCM obj);
 293 extern SCM scm_unprotect_object (SCM obj);
 294 extern int scm_init_storage (scm_sizet init_heap_size, int trig,
 295                              scm_sizet init_heap2_size, int trig2,
 296                              scm_sizet max_segment_size);
 297 extern void scm_init_gc (void);
 298 #endif  /* GCH */
 299
 300 /*
 301   Local Variables:
 302   c-file-style: "gnu"
 303   End:
 304 */