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 /* Low level cell data accessing macros:
 170  */
 171
 172 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 173 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
 174 #else
 175 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
 176 #endif
 177
 178 #define SCM_CELL_WORD(x, n) \
 179   SCM_VALIDATE_CELL ((x), ((const scm_t_bits *) SCM2PTR (x)) [n])
 180 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
 181 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
 182 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
 183 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 184
 185 #define SCM_CELL_OBJECT(x, n) \
 186   SCM_VALIDATE_CELL ((x), SCM_PACK (((const scm_t_bits *) SCM2PTR (x)) [n]))
 187 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 188 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 189 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 190 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 191
 192 #define SCM_SET_CELL_WORD(x, n, v) \
 193   SCM_VALIDATE_CELL ((x), ((scm_t_bits *) SCM2PTR (x)) [n] = (scm_t_bits) (v))
 194 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 195 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 196 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 197 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 198
 199 #define SCM_SET_CELL_OBJECT(x, n, v) \
 200   SCM_VALIDATE_CELL ((x), ((scm_t_bits *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 201 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 202 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 203 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 204 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 205
 206 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 207 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 208
 209
 210 /* Except for the garbage collector, no part of guile should ever run over a
 211  * free cell.  Thus, in debug mode the above macros report an error if they
 212  * are applied to a free cell.  Since the garbage collector is allowed to
 213  * access free cells, it needs its own way to access cells which will not
 214  * result in errors when in debug mode.  */
 215
 216 #define SCM_GC_CELL_TYPE(x) \
 217   (((const scm_t_bits *) SCM2PTR (x)) [0])
 218
 219
 220 #define SCM_CELL_WORD_LOC(x, n) ((scm_t_bits *) & SCM_CELL_WORD (x, n))
 221 #define SCM_CARLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 0))
 222 #define SCM_CDRLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 1))
 223
 224
 225 /* SCM_PTR_LT and friends define how to compare two SCM_CELLPTRs (which may
 226  * point to cells in different heap segments).
 227  */
 228 #define SCM_PTR_LT(x, y) ((x) < (y))
 229 #define SCM_PTR_GT(x, y) (SCM_PTR_LT (y, x))
 230 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 231 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 232
 233
 234 /* Freelists consist of linked cells where the type entry holds the value
 235  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 236  * the freelist.  Due to this structure, freelist cells are not cons cells
 237  * and thus may not be accessed using SCM_CAR and SCM_CDR.
 238  */
 239
 240 #define SCM_FREE_CELL_P(x) \
 241   (!SCM_IMP (x) && (* (const scm_t_bits *) SCM2PTR (x) == scm_tc_free_cell))
 242 #define SCM_FREE_CELL_CDR(x) \
 243   (SCM_PACK (((const scm_t_bits *) SCM2PTR (x)) [1]))
 244 #define SCM_SET_FREE_CELL_CDR(x, v) \
 245   (((scm_t_bits *) SCM2PTR (x)) [1] = SCM_UNPACK (v))
 246
 247
 248 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 249 #  define SCM_GC_SET_ALLOCATED(x) \
 250      (((scm_t_bits *) SCM2PTR (x)) [0] = scm_tc16_allocated)
 251 #else
 252 #  define SCM_GC_SET_ALLOCATED(x)
 253 #endif
 254
 255 #ifdef GUILE_DEBUG_FREELIST
 256 #define SCM_NEWCELL(_into) do { _into = scm_debug_newcell (); } while (0)
 257 #define SCM_NEWCELL2(_into) do { _into = scm_debug_newcell2 (); } while (0)
 258 #else
 259 /* When we introduce POSIX threads support, every thread will have
 260    a freelist of its own.  */
 261 #define SCM_NEWCELL(_into) \
 262         do { \
 263           if (SCM_NULLP (scm_freelist)) \
 264             { \
 265              _into = scm_gc_for_newcell (&scm_master_freelist, \
 266                                          &scm_freelist); \
 267              SCM_GC_SET_ALLOCATED (_into); \
 268             } \
 269           else \
 270             { \
 271                _into = scm_freelist; \
 272                scm_freelist = SCM_FREE_CELL_CDR (scm_freelist); \
 273                SCM_GC_SET_ALLOCATED (_into); \
 274             } \
 275         } while(0)
 276 #define SCM_NEWCELL2(_into) \
 277         do { \
 278           if (SCM_NULLP (scm_freelist2)) \
 279             { \
 280              _into = scm_gc_for_newcell (&scm_master_freelist2, \
 281                                          &scm_freelist2); \
 282              SCM_GC_SET_ALLOCATED (_into); \
 283             } \
 284           else \
 285             { \
 286                _into = scm_freelist2; \
 287                scm_freelist2 = SCM_FREE_CELL_CDR (scm_freelist2); \
 288                SCM_GC_SET_ALLOCATED (_into); \
 289             } \
 290         } while(0)
 291 #endif
 292
 293
 294 #define SCM_MARKEDP    SCM_GCMARKP
 295 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 296
 297 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 298 SCM_API scm_t_bits scm_tc16_allocated;
 299 SCM_API unsigned int scm_debug_cell_accesses_p;
 300 #endif
 301
 302 SCM_API struct scm_t_heap_seg_data *scm_heap_table;
 303 SCM_API size_t scm_n_heap_segs;
 304 SCM_API int scm_block_gc;
 305 SCM_API int scm_gc_heap_lock;
 306 SCM_API unsigned int scm_gc_running_p;
 307 \f
 308
 309 SCM_API size_t scm_default_init_heap_size_1;
 310 SCM_API int scm_default_min_yield_1;
 311 SCM_API size_t scm_default_init_heap_size_2;
 312 SCM_API int scm_default_min_yield_2;
 313 SCM_API size_t scm_default_max_segment_size;
 314
 315 SCM_API size_t scm_max_segment_size;
 316 SCM_API SCM_CELLPTR scm_heap_org;
 317 SCM_API SCM scm_freelist;
 318 SCM_API struct scm_t_freelist scm_master_freelist;
 319 SCM_API SCM scm_freelist2;
 320 SCM_API struct scm_t_freelist scm_master_freelist2;
 321 SCM_API unsigned long scm_gc_cells_collected;
 322 SCM_API unsigned long scm_gc_yield;
 323 SCM_API unsigned long scm_gc_malloc_collected;
 324 SCM_API unsigned long scm_gc_ports_collected;
 325 SCM_API unsigned long scm_cells_allocated;
 326 SCM_API unsigned long scm_mallocated;
 327 SCM_API unsigned long scm_mtrigger;
 328
 329 SCM_API SCM scm_after_gc_hook;
 330
 331 SCM_API scm_t_c_hook scm_before_gc_c_hook;
 332 SCM_API scm_t_c_hook scm_before_mark_c_hook;
 333 SCM_API scm_t_c_hook scm_before_sweep_c_hook;
 334 SCM_API scm_t_c_hook scm_after_sweep_c_hook;
 335 SCM_API scm_t_c_hook scm_after_gc_c_hook;
 336
 337 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 338 SCM_API SCM scm_map_free_list (void);
 339 SCM_API SCM scm_free_list_length (void);
 340 #endif
 341 #ifdef GUILE_DEBUG_FREELIST
 342 SCM_API SCM scm_debug_newcell (void);
 343 SCM_API SCM scm_debug_newcell2 (void);
 344 SCM_API SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 345 #endif
 346
 347 \f
 348
 349 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 350 SCM_API void scm_assert_cell_valid (SCM);
 351 SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag);
 352 #endif
 353 SCM_API SCM scm_object_address (SCM obj);
 354 SCM_API SCM scm_unhash_name (SCM name);
 355 SCM_API SCM scm_gc_stats (void);
 356 SCM_API SCM scm_gc (void);
 357 SCM_API void scm_gc_for_alloc (struct scm_t_freelist *freelist);
 358 SCM_API SCM scm_gc_for_newcell (struct scm_t_freelist *master, SCM *freelist);
 359 #if 0
 360 SCM_API void scm_alloc_cluster (struct scm_t_freelist *master);
 361 #endif
 362 SCM_API void scm_igc (const char *what);
 363 SCM_API void scm_gc_mark (SCM p);
 364 SCM_API void scm_gc_mark_dependencies (SCM p);
 365 SCM_API void scm_mark_locations (SCM_STACKITEM x[], unsigned long n);
 366 SCM_API int scm_cellp (SCM value);
 367 SCM_API void scm_gc_sweep (void);
 368 SCM_API void * scm_must_malloc (size_t len, const char *what);
 369 SCM_API void * scm_must_realloc (void *where,
 370                                  size_t olen, size_t len,
 371                                  const char *what);
 372 SCM_API char *scm_must_strdup (const char *str);
 373 SCM_API char *scm_must_strndup (const char *str, size_t n);
 374 SCM_API void scm_done_malloc (long size);
 375 SCM_API void scm_done_free (long size);
 376 SCM_API void scm_must_free (void *obj);
 377 SCM_API void scm_remember_upto_here_1 (SCM obj);
 378 SCM_API void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 379 SCM_API void scm_remember_upto_here (SCM obj1, ...);
 380 SCM_API SCM scm_return_first (SCM elt, ...);
 381 SCM_API int scm_return_first_int (int x, ...);
 382 SCM_API SCM scm_permanent_object (SCM obj);
 383 SCM_API SCM scm_gc_protect_object (SCM obj);
 384 SCM_API SCM scm_gc_unprotect_object (SCM obj);
 385 SCM_API void scm_gc_register_root (SCM *p);
 386 SCM_API void scm_gc_unregister_root (SCM *p);
 387 SCM_API void scm_gc_register_roots (SCM *b, unsigned long n);
 388 SCM_API void scm_gc_unregister_roots (SCM *b, unsigned long n);
 389 SCM_API int scm_init_storage (void);
 390 SCM_API void *scm_get_stack_base (void);
 391 SCM_API void scm_init_gc (void);
 392
 393 #endif  /* SCM_GC_H */
 394
 395 /*
 396   Local Variables:
 397   c-file-style: "gnu"
 398   End:
 399 */