libguile/gc.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_GC_H
   4 #define SCM_GC_H
   5
   6 /* Copyright (C) 1995,1996,1998,1999,2000,2001 Free Software Foundation, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this software; see the file COPYING.  If not, write to
  20  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  21  * Boston, MA 02111-1307 USA
  22  *
  23  * As a special exception, the Free Software Foundation gives permission
  24  * for additional uses of the text contained in its release of GUILE.
  25  *
  26  * The exception is that, if you link the GUILE library with other files
  27  * to produce an executable, this does not by itself cause the
  28  * resulting executable to be covered by the GNU General Public License.
  29  * Your use of that executable is in no way restricted on account of
  30  * linking the GUILE library code into it.
  31  *
  32  * This exception does not however invalidate any other reasons why
  33  * the executable file might be covered by the GNU General Public License.
  34  *
  35  * This exception applies only to the code released by the
  36  * Free Software Foundation under the name GUILE.  If you copy
  37  * code from other Free Software Foundation releases into a copy of
  38  * GUILE, as the General Public License permits, the exception does
  39  * not apply to the code that you add in this way.  To avoid misleading
  40  * anyone as to the status of such modified files, you must delete
  41  * this exception notice from them.
  42  *
  43  * If you write modifications of your own for GUILE, it is your choice
  44  * whether to permit this exception to apply to your modifications.
  45  * If you do not wish that, delete this exception notice.  */
  46
  47 \f
  48
  49 #include "libguile/__scm.h"
  50
  51 #include "libguile/hooks.h"
  52
  53 \f
  54
  55 typedef struct scm_cell
  56 {
  57   scm_t_bits word_0;
  58   scm_t_bits word_1;
  59 } scm_cell;
  60
  61
  62 /* SCM_CELLPTR is a pointer to a cons cell which may be compared or
  63  * differenced.
  64  */
  65 typedef scm_cell * SCM_CELLPTR;
  66
  67
  68 /* Cray machines have pointers that are incremented once for each word,
  69  * rather than each byte, the 3 most significant bits encode the byte
  70  * within the word.  The following macros deal with this by storing the
  71  * native Cray pointers like the ones that looks like scm expects.  This
  72  * is done for any pointers that might appear in the car of a scm_cell,
  73  * pointers to scm_vector elts, functions, &c are not munged.
  74  */
  75 #ifdef _UNICOS
  76 #  define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x) >> 3))
  77 #  define PTR2SCM(x) (SCM_PACK (((scm_t_bits) (x)) << 3))
  78 #else
  79 #  define SCM2PTR(x) ((SCM_CELLPTR) (SCM_UNPACK (x)))
  80 #  define PTR2SCM(x) (SCM_PACK ((scm_t_bits) (x)))
  81 #endif /* def _UNICOS */
  82
  83 #define SCM_GC_CARD_N_HEADER_CELLS 1
  84 #define SCM_GC_CARD_N_CELLS        256
  85
  86 #define SCM_GC_CARD_SIZE           (SCM_GC_CARD_N_CELLS * sizeof (scm_cell))
  87 #define SCM_GC_CARD_N_DATA_CELLS   (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS)
  88
  89 #define SCM_GC_CARD_BVEC_SIZE_IN_LIMBS \
  90     ((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LIMB_BITS - 1) / SCM_C_BVEC_LIMB_BITS)
  91
  92 #define SCM_GC_IN_CARD_HEADERP(x) \
  93     SCM_PTR_LT ((scm_cell *) (x), SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS)
  94
  95 #define SCM_GC_CARD_BVEC(card)  ((scm_t_c_bvec_limb *) ((card)->word_0))
  96 #define SCM_GC_SET_CARD_BVEC(card, bvec) \
  97     ((card)->word_0 = (scm_t_bits) (bvec))
  98
  99 #define SCM_GC_GET_CARD_FLAGS(card) ((long) ((card)->word_1))
 100 #define SCM_GC_SET_CARD_FLAGS(card, flags) \
 101     ((card)->word_1 = (scm_t_bits) (flags))
 102 #define SCM_GC_CLR_CARD_FLAGS(card) (SCM_GC_SET_CARD_FLAGS (card, 0L))
 103
 104 #define SCM_GC_GET_CARD_FLAG(card, shift) (SCM_GC_GET_CARD_FLAGS (card) & (1L << (shift)))
 105 #define SCM_GC_SET_CARD_FLAG(card, shift) \
 106     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) | (1L << (shift))))
 107 #define SCM_GC_CLR_CARD_FLAG(card, shift) \
 108     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) & ~(1L << (shift))))
 109
 110 #define SCM_GC_CARDF_DOUBLECELL 0
 111
 112 #define SCM_GC_CARD_DOUBLECELLP(card)    SCM_GC_GET_CARD_FLAG (card, SCM_GC_CARDF_DOUBLECELL)
 113 #define SCM_GC_SET_CARD_DOUBLECELL(card) SCM_GC_SET_CARD_FLAG (card, SCM_GC_CARDF_DOUBLECELL)
 114
 115 /* card addressing. for efficiency, cards are *always* aligned to
 116    SCM_GC_CARD_SIZE. */
 117
 118 #define SCM_GC_CARD_SIZE_MASK  (SCM_GC_CARD_SIZE - 1)
 119 #define SCM_GC_CARD_ADDR_MASK  (~SCM_GC_CARD_SIZE_MASK)
 120
 121 #define SCM_GC_CELL_CARD(x)    ((SCM_CELLPTR) ((long) (x) & SCM_GC_CARD_ADDR_MASK))
 122 #define SCM_GC_CELL_SPAN(x)    ((SCM_GC_CARD_DOUBLECELLP (SCM_GC_CELL_CARD (x))) ? 2 : 1)
 123 #define SCM_GC_CELL_OFFSET(x)  (((long) (x) & SCM_GC_CARD_SIZE_MASK) >> SCM_CELL_SIZE_SHIFT)
 124 #define SCM_GC_CELL_BVEC(x)    SCM_GC_CARD_BVEC (SCM_GC_CELL_CARD (x))
 125 #define SCM_GC_CELL_GET_BIT(x) SCM_C_BVEC_GET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 126 #define SCM_GC_CELL_SET_BIT(x) SCM_C_BVEC_SET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 127 #define SCM_GC_CELL_CLR_BIT(x) SCM_C_BVEC_CLR (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 128
 129 #define SCM_GC_CARD_UP(x)      SCM_GC_CELL_CARD ((char *) (x) + SCM_GC_CARD_SIZE - 1)
 130 #define SCM_GC_CARD_DOWN       SCM_GC_CELL_CARD
 131
 132 /* low level bit banging aids */
 133
 134 typedef unsigned long scm_t_c_bvec_limb;
 135
 136 #if (SIZEOF_LONG == 8)
 137 #       define SCM_C_BVEC_LIMB_BITS    64
 138 #       define SCM_C_BVEC_OFFSET_SHIFT 6
 139 #       define SCM_C_BVEC_POS_MASK     63
 140 #       define SCM_CELL_SIZE_SHIFT     4
 141 #else
 142 #       define SCM_C_BVEC_LIMB_BITS    32
 143 #       define SCM_C_BVEC_OFFSET_SHIFT 5
 144 #       define SCM_C_BVEC_POS_MASK     31
 145 #       define SCM_CELL_SIZE_SHIFT     3
 146 #endif
 147
 148 #define SCM_C_BVEC_OFFSET(pos) (pos >> SCM_C_BVEC_OFFSET_SHIFT)
 149
 150 #define SCM_C_BVEC_GET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] & (1L << (pos & SCM_C_BVEC_POS_MASK)))
 151 #define SCM_C_BVEC_SET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] |= (1L << (pos & SCM_C_BVEC_POS_MASK)))
 152 #define SCM_C_BVEC_CLR(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] &= ~(1L << (pos & SCM_C_BVEC_POS_MASK)))
 153
 154 #define SCM_C_BVEC_BITS2BYTES(bits) \
 155     (sizeof (scm_t_c_bvec_limb) * ((((bits) & SCM_C_BVEC_POS_MASK) ? 1L : 0L) + SCM_C_BVEC_OFFSET (bits)))
 156
 157 #define SCM_C_BVEC_SET_BYTES(bvec, bytes)   (memset (bvec, 0xff, bytes))
 158 #define SCM_C_BVEC_SET_ALL_BITS(bvec, bits) SCM_C_BVEC_SET_BYTES (bvec, SCM_C_BVEC_BITS2BYTES (bits))
 159
 160 #define SCM_C_BVEC_CLR_BYTES(bvec, bytes)   (memset (bvec, 0, bytes))
 161 #define SCM_C_BVEC_CLR_ALL_BITS(bvec, bits) SCM_C_BVEC_CLR_BYTES (bvec, SCM_C_BVEC_BITS2BYTES (bits))
 162
 163 /* testing and changing GC marks */
 164
 165 #define SCM_GCMARKP(x)   SCM_GC_CELL_GET_BIT (x)
 166 #define SCM_SETGCMARK(x) SCM_GC_CELL_SET_BIT (x)
 167 #define SCM_CLRGCMARK(x) SCM_GC_CELL_CLR_BIT (x)
 168
 169
 170 /* Low level cell data accessing macros.  These macros should only be used
 171  * from within code related to garbage collection issues, since they will
 172  * never check the cells they are applied to - not even if guile is compiled
 173  * in debug mode.  In particular these macros will even work for free cells,
 174  * which should never be encountered by user code.  */
 175
 176 #define SCM_GC_CELL_WORD(x, n) \
 177   (((const scm_t_bits *) SCM2PTR (x)) [n])
 178 #define SCM_GC_CELL_OBJECT(x, n) \
 179   (SCM_PACK (((const scm_t_bits *) SCM2PTR (x)) [n]))
 180 #define SCM_GC_SET_CELL_WORD(x, n, v) \
 181   (((scm_t_bits *) SCM2PTR (x)) [n] = (scm_t_bits) (v))
 182 #define SCM_GC_SET_CELL_OBJECT(x, n, v) \
 183   (((scm_t_bits *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 184 #define SCM_GC_CELL_TYPE(x) SCM_GC_CELL_WORD (x, 0)
 185
 186
 187 /* Except for the garbage collector, no part of guile should ever run over a
 188  * free cell.  Thus, if guile is compiled in debug mode the SCM_CELL_* and
 189  * SCM_SET_CELL_* macros below report an error if they are applied to a free
 190  * cell.  Some other plausibility checks are also performed.  However, if
 191  * guile is not compiled in debug mode, there won't be any time penalty at all
 192  * when using these macros.  */
 193
 194 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 195 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
 196 #else
 197 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
 198 #endif
 199
 200 #define SCM_CELL_WORD(x, n) \
 201   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_WORD ((x), (n)))
 202 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
 203 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
 204 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
 205 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 206
 207 #define SCM_CELL_OBJECT(x, n) \
 208   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_OBJECT ((x), (n)))
 209 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 210 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 211 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 212 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 213
 214 #define SCM_SET_CELL_WORD(x, n, v) \
 215   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_WORD ((x), (n), (v)))
 216 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 217 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 218 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 219 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 220
 221 #define SCM_SET_CELL_OBJECT(x, n, v) \
 222   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_OBJECT ((x), (n), (v)))
 223 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 224 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 225 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 226 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 227
 228 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 229 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 230
 231
 232 /* Freelists consist of linked cells where the type entry holds the value
 233  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 234  * the freelist.  Due to this structure, freelist cells are not cons cells
 235  * and thus may not be accessed using SCM_CAR and SCM_CDR.  */
 236
 237 #define SCM_FREE_CELL_P(x) \
 238   (!SCM_IMP (x) && (SCM_GC_CELL_TYPE (x) == scm_tc_free_cell))
 239 #define SCM_FREE_CELL_CDR(x) \
 240   (SCM_GC_CELL_OBJECT ((x), 1))
 241 #define SCM_SET_FREE_CELL_CDR(x, v) \
 242   (SCM_GC_SET_CELL_OBJECT ((x), 1, (v)))
 243
 244
 245 #define SCM_CELL_WORD_LOC(x, n) ((scm_t_bits *) & SCM_CELL_WORD (x, n))
 246 #define SCM_CARLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 0))
 247 #define SCM_CDRLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 1))
 248
 249
 250 /* SCM_PTR_LT and friends define how to compare two SCM_CELLPTRs (which may
 251  * point to cells in different heap segments).
 252  */
 253 #define SCM_PTR_LT(x, y) ((x) < (y))
 254 #define SCM_PTR_GT(x, y) (SCM_PTR_LT (y, x))
 255 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 256 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 257
 258
 259 #define SCM_MARKEDP    SCM_GCMARKP
 260 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 261
 262 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 263 SCM_API unsigned int scm_debug_cell_accesses_p;
 264 #endif
 265
 266 SCM_API struct scm_t_heap_seg_data *scm_heap_table;
 267 SCM_API size_t scm_n_heap_segs;
 268 SCM_API int scm_block_gc;
 269 SCM_API int scm_gc_heap_lock;
 270 SCM_API unsigned int scm_gc_running_p;
 271 \f
 272
 273 SCM_API size_t scm_default_init_heap_size_1;
 274 SCM_API int scm_default_min_yield_1;
 275 SCM_API size_t scm_default_init_heap_size_2;
 276 SCM_API int scm_default_min_yield_2;
 277 SCM_API size_t scm_default_max_segment_size;
 278
 279 SCM_API size_t scm_max_segment_size;
 280 SCM_API SCM_CELLPTR scm_heap_org;
 281 SCM_API SCM scm_freelist;
 282 SCM_API struct scm_t_freelist scm_master_freelist;
 283 SCM_API SCM scm_freelist2;
 284 SCM_API struct scm_t_freelist scm_master_freelist2;
 285 SCM_API unsigned long scm_gc_cells_collected;
 286 SCM_API unsigned long scm_gc_yield;
 287 SCM_API unsigned long scm_gc_malloc_collected;
 288 SCM_API unsigned long scm_gc_ports_collected;
 289 SCM_API unsigned long scm_cells_allocated;
 290 SCM_API unsigned long scm_mallocated;
 291 SCM_API unsigned long scm_mtrigger;
 292
 293 SCM_API SCM scm_after_gc_hook;
 294
 295 SCM_API scm_t_c_hook scm_before_gc_c_hook;
 296 SCM_API scm_t_c_hook scm_before_mark_c_hook;
 297 SCM_API scm_t_c_hook scm_before_sweep_c_hook;
 298 SCM_API scm_t_c_hook scm_after_sweep_c_hook;
 299 SCM_API scm_t_c_hook scm_after_gc_c_hook;
 300
 301 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 302 SCM_API SCM scm_map_free_list (void);
 303 SCM_API SCM scm_free_list_length (void);
 304 #endif
 305 #ifdef GUILE_DEBUG_FREELIST
 306 SCM_API SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 307 #endif
 308
 309 \f
 310
 311 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 312 SCM_API void scm_assert_cell_valid (SCM);
 313 SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag);
 314 #endif
 315 SCM_API SCM scm_object_address (SCM obj);
 316 SCM_API SCM scm_gc_stats (void);
 317 SCM_API SCM scm_gc (void);
 318 SCM_API void scm_gc_for_alloc (struct scm_t_freelist *freelist);
 319 SCM_API SCM scm_gc_for_newcell (struct scm_t_freelist *master, SCM *freelist);
 320 #if 0
 321 SCM_API void scm_alloc_cluster (struct scm_t_freelist *master);
 322 #endif
 323 SCM_API void scm_igc (const char *what);
 324 SCM_API void scm_gc_mark (SCM p);
 325 SCM_API void scm_gc_mark_dependencies (SCM p);
 326 SCM_API void scm_mark_locations (SCM_STACKITEM x[], unsigned long n);
 327 SCM_API int scm_cellp (SCM value);
 328 SCM_API void scm_gc_sweep (void);
 329
 330 SCM_API void *scm_malloc (size_t size);
 331 SCM_API void *scm_realloc (void *mem, size_t size);
 332 SCM_API char *scm_strdup (const char *str);
 333 SCM_API char *scm_strndup (const char *str, size_t n);
 334 SCM_API void scm_gc_register_collectable_memory (void *mem, size_t size,
 335                                                  const char *what);
 336 SCM_API void scm_gc_unregister_collectable_memory (void *mem, size_t size,
 337                                                    const char *what);
 338 SCM_API void *scm_gc_malloc (size_t size, const char *what);
 339 SCM_API void *scm_gc_realloc (void *mem, size_t old_size,
 340                               size_t new_size, const char *what);
 341 SCM_API void scm_gc_free (void *mem, size_t size, const char *what);
 342 SCM_API char *scm_gc_strdup (const char *str, const char *what);
 343 SCM_API char *scm_gc_strndup (const char *str, size_t n, const char *what);
 344
 345 SCM_API void scm_remember_upto_here_1 (SCM obj);
 346 SCM_API void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 347 SCM_API void scm_remember_upto_here (SCM obj1, ...);
 348 SCM_API SCM scm_return_first (SCM elt, ...);
 349 SCM_API int scm_return_first_int (int x, ...);
 350 SCM_API SCM scm_permanent_object (SCM obj);
 351 SCM_API SCM scm_gc_protect_object (SCM obj);
 352 SCM_API SCM scm_gc_unprotect_object (SCM obj);
 353 SCM_API void scm_gc_register_root (SCM *p);
 354 SCM_API void scm_gc_unregister_root (SCM *p);
 355 SCM_API void scm_gc_register_roots (SCM *b, unsigned long n);
 356 SCM_API void scm_gc_unregister_roots (SCM *b, unsigned long n);
 357 SCM_API int scm_init_storage (void);
 358 SCM_API void *scm_get_stack_base (void);
 359 SCM_API void scm_init_gc (void);
 360
 361 #if SCM_ENABLE_DEPRECATED == 1
 362
 363 SCM_API SCM scm_deprecated_newcell (void);
 364 SCM_API SCM scm_deprecated_newcell2 (void);
 365
 366 #define SCM_NEWCELL(_into) \
 367   do { _into = scm_deprecated_newcell (); } while (0)
 368 #define SCM_NEWCELL2(_into) \
 369   do { _into = scm_deprecated_newcell2 (); } while (0)
 370
 371 SCM_API void * scm_must_malloc (size_t len, const char *what);
 372 SCM_API void * scm_must_realloc (void *where,
 373                                  size_t olen, size_t len,
 374                                  const char *what);
 375 SCM_API char *scm_must_strdup (const char *str);
 376 SCM_API char *scm_must_strndup (const char *str, size_t n);
 377 SCM_API void scm_done_malloc (long size);
 378 SCM_API void scm_done_free (long size);
 379 SCM_API void scm_must_free (void *obj);
 380
 381 #endif
 382
 383 #endif  /* SCM_GC_H */
 384
 385 /*
 386   Local Variables:
 387   c-file-style: "gnu"
 388   End:
 389 */