libguile/gc.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_GC_H
   4 #define SCM_GC_H
   5 /* Copyright (C) 1995,1996,1998,1999,2000,2001 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 #define SCM_GC_CARD_N_HEADER_CELLS 1
  85 #define SCM_GC_CARD_N_CELLS        256
  86
  87 #define SCM_GC_CARD_SIZE           (SCM_GC_CARD_N_CELLS * sizeof (scm_cell))
  88 #define SCM_GC_CARD_N_DATA_CELLS   (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS)
  89
  90 #define SCM_GC_CARD_BVEC_SIZE_IN_LIMBS \
  91     ((SCM_GC_CARD_N_CELLS + SCM_C_BVEC_LIMB_BITS - 1) / SCM_C_BVEC_LIMB_BITS)
  92
  93 #define SCM_GC_IN_CARD_HEADERP(x) \
  94     SCM_PTR_LT ((scm_cell *) (x), SCM_GC_CELL_CARD (x) + SCM_GC_CARD_N_HEADER_CELLS)
  95
  96 #define SCM_GC_CARD_BVEC(card)  ((scm_c_bvec_limb_t *) ((card)->word_0))
  97 #define SCM_GC_SET_CARD_BVEC(card, bvec) \
  98     ((card)->word_0 = (scm_bits_t) (bvec))
  99
 100 #define SCM_GC_GET_CARD_FLAGS(card) ((scm_ubits_t) ((card)->word_1))
 101 #define SCM_GC_SET_CARD_FLAGS(card, flags) \
 102     ((card)->word_1 = (scm_bits_t) (flags))
 103 #define SCM_GC_CLR_CARD_FLAGS(card) (SCM_GC_SET_CARD_FLAGS (card, 0L))
 104
 105 #define SCM_GC_GET_CARD_FLAG(card, shift) (SCM_GC_GET_CARD_FLAGS (card) & (1L << (shift)))
 106 #define SCM_GC_SET_CARD_FLAG(card, shift) \
 107     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) | (1L << (shift))))
 108 #define SCM_GC_CLR_CARD_FLAG(card, shift) \
 109     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) & ~(1L << (shift))))
 110
 111 #define SCM_GC_CARDF_DOUBLECELL 0
 112
 113 #define SCM_GC_CARD_DOUBLECELLP(card)    SCM_GC_GET_CARD_FLAG (card, SCM_GC_CARDF_DOUBLECELL)
 114 #define SCM_GC_SET_CARD_DOUBLECELL(card) SCM_GC_SET_CARD_FLAG (card, SCM_GC_CARDF_DOUBLECELL)
 115
 116 /* card addressing. for efficiency, cards are *always* aligned to
 117    SCM_GC_CARD_SIZE. */
 118
 119 #define SCM_GC_CARD_SIZE_MASK  (SCM_GC_CARD_SIZE - 1)
 120 #define SCM_GC_CARD_ADDR_MASK  (~SCM_GC_CARD_SIZE_MASK)
 121
 122 #define SCM_GC_CELL_CARD(x)    ((SCM_CELLPTR) ((scm_bits_t) (x) & SCM_GC_CARD_ADDR_MASK))
 123 #define SCM_GC_CELL_SPAN(x)    ((SCM_GC_CARD_DOUBLECELLP (SCM_GC_CELL_CARD (x))) ? 2 : 1)
 124 #define SCM_GC_CELL_OFFSET(x)  (((scm_bits_t) (x) & SCM_GC_CARD_SIZE_MASK) >> SCM_CELL_SIZE_SHIFT)
 125 #define SCM_GC_CELL_BVEC(x)    SCM_GC_CARD_BVEC (SCM_GC_CELL_CARD (x))
 126 #define SCM_GC_CELL_GET_BIT(x) SCM_C_BVEC_GET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 127 #define SCM_GC_CELL_SET_BIT(x) SCM_C_BVEC_SET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 128 #define SCM_GC_CELL_CLR_BIT(x) SCM_C_BVEC_CLR (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 129
 130 #define SCM_GC_CARD_UP(x)      SCM_GC_CELL_CARD ((char *) (x) + SCM_GC_CARD_SIZE - 1)
 131 #define SCM_GC_CARD_DOWN       SCM_GC_CELL_CARD
 132
 133 /* low level bit banging aids */
 134
 135 typedef unsigned long scm_c_bvec_limb_t;
 136
 137 #if (SIZEOF_LONG == 8)
 138 #       define SCM_C_BVEC_LIMB_BITS    64
 139 #       define SCM_C_BVEC_OFFSET_SHIFT 6
 140 #       define SCM_C_BVEC_POS_MASK     63
 141 #       define SCM_CELL_SIZE_SHIFT     4
 142 #else
 143 #       define SCM_C_BVEC_LIMB_BITS    32
 144 #       define SCM_C_BVEC_OFFSET_SHIFT 5
 145 #       define SCM_C_BVEC_POS_MASK     31
 146 #       define SCM_CELL_SIZE_SHIFT     3
 147 #endif
 148
 149 #define SCM_C_BVEC_OFFSET(pos) (pos >> SCM_C_BVEC_OFFSET_SHIFT)
 150
 151 #define SCM_C_BVEC_GET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] & (1L << (pos & SCM_C_BVEC_POS_MASK)))
 152 #define SCM_C_BVEC_SET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] |= (1L << (pos & SCM_C_BVEC_POS_MASK)))
 153 #define SCM_C_BVEC_CLR(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] &= ~(1L << (pos & SCM_C_BVEC_POS_MASK)))
 154
 155 #define SCM_C_BVEC_BITS2BYTES(bits) \
 156     (sizeof (scm_c_bvec_limb_t) * ((((bits) & SCM_C_BVEC_POS_MASK) ? 1L : 0L) + SCM_C_BVEC_OFFSET (bits)))
 157
 158 #define SCM_C_BVEC_SET_BYTES(bvec, bytes)   (memset (bvec, 0xff, bytes))
 159 #define SCM_C_BVEC_SET_ALL_BITS(bvec, bits) SCM_C_BVEC_SET_BYTES (bvec, SCM_C_BVEC_BITS2BYTES (bits))
 160
 161 #define SCM_C_BVEC_CLR_BYTES(bvec, bytes)   (memset (bvec, 0, bytes))
 162 #define SCM_C_BVEC_CLR_ALL_BITS(bvec, bits) SCM_C_BVEC_CLR_BYTES (bvec, SCM_C_BVEC_BITS2BYTES (bits))
 163
 164 /* testing and changing GC marks */
 165
 166 #define SCM_GCMARKP(x)   SCM_GC_CELL_GET_BIT (x)
 167 #define SCM_SETGCMARK(x) SCM_GC_CELL_SET_BIT (x)
 168 #define SCM_CLRGCMARK(x) SCM_GC_CELL_CLR_BIT (x)
 169
 170 /* Low level cell data accessing macros:
 171  */
 172
 173 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 174 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
 175 #else
 176 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
 177 #endif
 178
 179 #define SCM_CELL_WORD(x, n) \
 180   SCM_VALIDATE_CELL ((x), ((const scm_bits_t *) SCM2PTR (x)) [n])
 181 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
 182 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
 183 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
 184 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 185
 186 #define SCM_CELL_OBJECT(x, n) \
 187   SCM_VALIDATE_CELL ((x), SCM_PACK (((const scm_bits_t *) SCM2PTR (x)) [n]))
 188 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 189 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 190 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 191 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 192
 193 #define SCM_SET_CELL_WORD(x, n, v) \
 194   SCM_VALIDATE_CELL ((x), ((scm_bits_t *) SCM2PTR (x)) [n] = (scm_bits_t) (v))
 195 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 196 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 197 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 198 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 199
 200 #define SCM_SET_CELL_OBJECT(x, n, v) \
 201   SCM_VALIDATE_CELL ((x), ((scm_bits_t *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 202 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 203 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 204 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 205 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 206
 207 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 208 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 209
 210
 211 /* Except for the garbage collector, no part of guile should ever run over a
 212  * free cell.  Thus, in debug mode the above macros report an error if they
 213  * are applied to a free cell.  Since the garbage collector is allowed to
 214  * access free cells, it needs its own way to access cells which will not
 215  * result in errors when in debug mode.  */
 216
 217 #define SCM_GC_CELL_TYPE(x) \
 218   (((const scm_bits_t *) SCM2PTR (x)) [0])
 219
 220
 221 #define SCM_CELL_WORD_LOC(x, n) ((scm_bits_t *) & SCM_CELL_WORD (x, n))
 222 #define SCM_CARLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 0))
 223 #define SCM_CDRLOC(x) ((SCM *) SCM_CELL_WORD_LOC ((x), 1))
 224
 225
 226 /* SCM_PTR_LT and friends define how to compare two SCM_CELLPTRs (which may
 227  * point to cells in different heap segments).
 228  */
 229 #define SCM_PTR_LT(x, y) ((x) < (y))
 230 #define SCM_PTR_GT(x, y) (SCM_PTR_LT (y, x))
 231 #define SCM_PTR_LE(x, y) (!SCM_PTR_GT (x, y))
 232 #define SCM_PTR_GE(x, y) (!SCM_PTR_LT (x, y))
 233
 234
 235 /* Freelists consist of linked cells where the type entry holds the value
 236  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 237  * the freelist.  Due to this structure, freelist cells are not cons cells
 238  * and thus may not be accessed using SCM_CAR and SCM_CDR.
 239  */
 240
 241 #define SCM_FREE_CELL_P(x) \
 242   (!SCM_IMP (x) && (* (const scm_bits_t *) SCM2PTR (x) == scm_tc_free_cell))
 243 #define SCM_FREE_CELL_CDR(x) \
 244   (SCM_PACK (((const scm_bits_t *) SCM2PTR (x)) [1]))
 245 #define SCM_SET_FREE_CELL_CDR(x, v) \
 246   (((scm_bits_t *) SCM2PTR (x)) [1] = SCM_UNPACK (v))
 247
 248
 249 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 250 #  define SCM_GC_SET_ALLOCATED(x) \
 251      (((scm_bits_t *) SCM2PTR (x)) [0] = scm_tc16_allocated)
 252 #else
 253 #  define SCM_GC_SET_ALLOCATED(x)
 254 #endif
 255
 256 #ifdef GUILE_DEBUG_FREELIST
 257 #define SCM_NEWCELL(_into) do { _into = scm_debug_newcell (); } while (0)
 258 #define SCM_NEWCELL2(_into) do { _into = scm_debug_newcell2 (); } while (0)
 259 #else
 260 /* When we introduce POSIX threads support, every thread will have
 261    a freelist of its own.  */
 262 #define SCM_NEWCELL(_into) \
 263         do { \
 264           if (SCM_NULLP (scm_freelist)) \
 265             { \
 266              _into = scm_gc_for_newcell (&scm_master_freelist, \
 267                                          &scm_freelist); \
 268              SCM_GC_SET_ALLOCATED (_into); \
 269             } \
 270           else \
 271             { \
 272                _into = scm_freelist; \
 273                scm_freelist = SCM_FREE_CELL_CDR (scm_freelist); \
 274                SCM_GC_SET_ALLOCATED (_into); \
 275             } \
 276         } while(0)
 277 #define SCM_NEWCELL2(_into) \
 278         do { \
 279           if (SCM_NULLP (scm_freelist2)) \
 280             { \
 281              _into = scm_gc_for_newcell (&scm_master_freelist2, \
 282                                          &scm_freelist2); \
 283              SCM_GC_SET_ALLOCATED (_into); \
 284             } \
 285           else \
 286             { \
 287                _into = scm_freelist2; \
 288                scm_freelist2 = SCM_FREE_CELL_CDR (scm_freelist2); \
 289                SCM_GC_SET_ALLOCATED (_into); \
 290             } \
 291         } while(0)
 292 #endif
 293
 294
 295 #define SCM_MARKEDP    SCM_GCMARKP
 296 #define SCM_NMARKEDP(x) (!SCM_MARKEDP (x))
 297
 298 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 299 extern scm_bits_t scm_tc16_allocated;
 300 extern unsigned int scm_debug_cell_accesses_p;
 301 #endif
 302
 303 extern struct scm_heap_seg_data_t *scm_heap_table;
 304 extern size_t scm_n_heap_segs;
 305 extern int scm_block_gc;
 306 extern int scm_gc_heap_lock;
 307 extern unsigned int scm_gc_running_p;
 308 \f
 309
 310 extern size_t scm_default_init_heap_size_1;
 311 extern int scm_default_min_yield_1;
 312 extern size_t scm_default_init_heap_size_2;
 313 extern int scm_default_min_yield_2;
 314 extern size_t scm_default_max_segment_size;
 315
 316 extern size_t scm_max_segment_size;
 317 extern SCM_CELLPTR scm_heap_org;
 318 extern SCM scm_freelist;
 319 extern struct scm_freelist_t scm_master_freelist;
 320 extern SCM scm_freelist2;
 321 extern struct scm_freelist_t scm_master_freelist2;
 322 extern scm_ubits_t scm_gc_cells_collected;
 323 extern scm_ubits_t scm_gc_yield;
 324 extern scm_ubits_t scm_gc_malloc_collected;
 325 extern scm_ubits_t scm_gc_ports_collected;
 326 extern scm_ubits_t scm_cells_allocated;
 327 extern scm_ubits_t scm_mallocated;
 328 extern scm_ubits_t scm_mtrigger;
 329
 330 extern SCM scm_after_gc_hook;
 331
 332 extern scm_c_hook_t scm_before_gc_c_hook;
 333 extern scm_c_hook_t scm_before_mark_c_hook;
 334 extern scm_c_hook_t scm_before_sweep_c_hook;
 335 extern scm_c_hook_t scm_after_sweep_c_hook;
 336 extern scm_c_hook_t scm_after_gc_c_hook;
 337
 338 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 339 extern SCM scm_map_free_list (void);
 340 extern SCM scm_free_list_length (void);
 341 #endif
 342 #ifdef GUILE_DEBUG_FREELIST
 343 extern SCM scm_debug_newcell (void);
 344 extern SCM scm_debug_newcell2 (void);
 345 extern SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 346 #endif
 347
 348 \f
 349
 350 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 351 extern void scm_assert_cell_valid (SCM);
 352 extern SCM scm_set_debug_cell_accesses_x (SCM flag);
 353 #endif
 354 extern SCM scm_object_address (SCM obj);
 355 extern SCM scm_unhash_name (SCM name);
 356 extern SCM scm_gc_stats (void);
 357 extern SCM scm_gc (void);
 358 extern void scm_gc_for_alloc (struct scm_freelist_t *freelist);
 359 extern SCM scm_gc_for_newcell (struct scm_freelist_t *master, SCM *freelist);
 360 #if 0
 361 extern void scm_alloc_cluster (struct scm_freelist_t *master);
 362 #endif
 363 extern void scm_igc (const char *what);
 364 extern void scm_gc_mark (SCM p);
 365 extern void scm_gc_mark_dependencies (SCM p);
 366 extern void scm_mark_locations (SCM_STACKITEM x[], scm_ubits_t n);
 367 extern int scm_cellp (SCM value);
 368 extern void scm_gc_sweep (void);
 369 extern void * scm_must_malloc (size_t len, const char *what);
 370 extern void * scm_must_realloc (void *where,
 371                                 size_t olen, size_t len,
 372                                 const char *what);
 373 extern void scm_done_malloc (scm_bits_t size);
 374 extern void scm_done_free (scm_bits_t size);
 375 extern char *scm_must_strdup (const char *str);
 376 extern char *scm_must_strndup (const char *str, size_t n);
 377 extern void scm_must_free (void *obj);
 378 extern void scm_remember_upto_here_1 (SCM obj);
 379 extern void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 380 extern void scm_remember_upto_here (SCM obj1, ...);
 381 extern SCM scm_return_first (SCM elt, ...);
 382 extern int scm_return_first_int (int x, ...);
 383 extern SCM scm_permanent_object (SCM obj);
 384 extern SCM scm_protect_object (SCM obj);
 385 extern SCM scm_unprotect_object (SCM obj);
 386 extern int scm_init_storage (void);
 387 extern void *scm_get_stack_base (void);
 388 extern void scm_init_gc (void);
 389
 390 \f
 391
 392 #if (SCM_DEBUG_DEPRECATED == 0)
 393
 394 #define SCM_SETAND_CAR(x, y) \
 395   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) & (y))))
 396 #define SCM_SETOR_CAR(x, y)\
 397   (SCM_SETCAR ((x), SCM_PACK (SCM_UNPACK (SCM_CAR (x)) | (y))))
 398 #define SCM_SETAND_CDR(x, y)\
 399   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) & (y))))
 400 #define SCM_SETOR_CDR(x, y)\
 401   (SCM_SETCDR ((x), SCM_PACK (SCM_UNPACK (SCM_CDR (x)) | (y))))
 402 #define SCM_FREEP(x) (SCM_FREE_CELL_P (x))
 403 #define SCM_NFREEP(x) (!SCM_FREE_CELL_P (x))
 404 #define SCM_GC8MARKP(x) SCM_GCMARKP (x)
 405 #define SCM_SETGC8MARK(x) SCM_SETGCMARK (x)
 406 #define SCM_CLRGC8MARK(x) SCM_CLRGCMARK (x)
 407 #define SCM_GCTYP16(x) SCM_TYP16 (x)
 408 #define SCM_GCCDR(x) SCM_CDR (x)
 409 extern void scm_remember (SCM * ptr);
 410
 411 #endif  /* SCM_DEBUG_DEPRECATED == 0 */
 412
 413 #endif  /* SCM_GC_H */
 414
 415 /*
 416   Local Variables:
 417   c-file-style: "gnu"
 418   End:
 419 */