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, 2002, 2003, 2004 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library 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 GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  */
  22
  23 \f
  24
  25 #include "libguile/__scm.h"
  26
  27 #include "libguile/hooks.h"
  28
  29 #if SCM_USE_PTHREAD_THREADS
  30 # include "libguile/pthread-threads.h"
  31 #else
  32 # include "libguile/null-threads.h"
  33 #endif
  34
  35 \f
  36
  37 typedef struct scm_t_cell
  38 {
  39   SCM word_0;
  40   SCM word_1;
  41 } scm_t_cell;
  42
  43 /*
  44   CARDS
  45
  46   A card is a small `page' of memory; it will be the unit for lazy
  47   sweeping, generations, etc. The first cell of a card contains a
  48   pointer to the mark bitvector, so that we can find the bitvector
  49   efficiently: we knock off some lowerorder bits.
  50
  51   The size on a 32 bit machine is 256 cells = 2kb. The card [XXX]
  52 */
  53
  54
  55
  56 /* Cray machines have pointers that are incremented once for each
  57  * word, rather than each byte, the 3 most significant bits encode the
  58  * byte within the word.  The following macros deal with this by
  59  * storing the native Cray pointers like the ones that looks like scm
  60  * expects.  This is done for any pointers that point to a cell,
  61  * pointers to scm_vector elts, functions, &c are not munged.
  62  */
  63 #ifdef _UNICOS
  64 #  define SCM2PTR(x) ((scm_t_cell *) (SCM_UNPACK (x) >> 3))
  65 #  define PTR2SCM(x) (SCM_PACK (((scm_t_bits) (x)) << 3))
  66 #else
  67 #  define SCM2PTR(x) ((scm_t_cell *) (SCM_UNPACK (x)))
  68 #  define PTR2SCM(x) (SCM_PACK ((scm_t_bits) (x)))
  69 #endif /* def _UNICOS */
  70
  71
  72 #define SCM_GC_CARD_N_HEADER_CELLS 1
  73 #define SCM_GC_CARD_N_CELLS        256
  74 #define SCM_GC_SIZEOF_CARD              SCM_GC_CARD_N_CELLS * sizeof (scm_t_cell)
  75
  76 #define SCM_GC_CARD_BVEC(card)  ((scm_t_c_bvec_long *) ((card)->word_0))
  77 #define SCM_GC_SET_CARD_BVEC(card, bvec) \
  78     ((card)->word_0 = (SCM) (bvec))
  79 #define SCM_GC_GET_CARD_FLAGS(card) ((long) ((card)->word_1))
  80 #define SCM_GC_SET_CARD_FLAGS(card, flags) \
  81     ((card)->word_1 = (SCM) (flags))
  82
  83 #define SCM_GC_GET_CARD_FLAG(card, shift) \
  84  (SCM_GC_GET_CARD_FLAGS (card) & (1L << (shift)))
  85 #define SCM_GC_SET_CARD_FLAG(card, shift) \
  86  (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) | (1L << (shift))))
  87 #define SCM_GC_CLEAR_CARD_FLAG(card, shift) \
  88  (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) & ~(1L << (shift))))
  89
  90 /*
  91   Remove card flags. They hamper lazy initialization, and aren't used
  92   anyways.
  93  */
  94
  95 /* card addressing. for efficiency, cards are *always* aligned to
  96    SCM_GC_CARD_SIZE. */
  97
  98 #define SCM_GC_CARD_SIZE_MASK  (SCM_GC_SIZEOF_CARD-1)
  99 #define SCM_GC_CARD_ADDR_MASK  (~SCM_GC_CARD_SIZE_MASK)
 100
 101 #define SCM_GC_CELL_CARD(x)    ((scm_t_cell *) ((long) (x) & SCM_GC_CARD_ADDR_MASK))
 102 #define SCM_GC_CELL_OFFSET(x)  (((long) (x) & SCM_GC_CARD_SIZE_MASK) >> SCM_CELL_SIZE_SHIFT)
 103 #define SCM_GC_CELL_BVEC(x)    SCM_GC_CARD_BVEC (SCM_GC_CELL_CARD (x))
 104 #define SCM_GC_SET_CELL_BVEC(x, bvec)    SCM_GC_SET_CARD_BVEC (SCM_GC_CELL_CARD (x), bvec)
 105 #define SCM_GC_CELL_GET_BIT(x) SCM_C_BVEC_GET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 106 #define SCM_GC_CELL_SET_BIT(x) SCM_C_BVEC_SET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 107 #define SCM_GC_CELL_CLEAR_BIT(x) SCM_C_BVEC_CLEAR (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 108
 109 #define SCM_GC_CARD_UP(x)      SCM_GC_CELL_CARD ((char *) (x) + SCM_GC_SIZEOF_CARD - 1)
 110 #define SCM_GC_CARD_DOWN       SCM_GC_CELL_CARD
 111
 112 /* low level bit banging aids */
 113 typedef unsigned long scm_t_c_bvec_long;
 114
 115 #if (SCM_SIZEOF_UNSIGNED_LONG == 8)
 116 #       define SCM_C_BVEC_LONG_BITS    64
 117 #       define SCM_C_BVEC_OFFSET_SHIFT 6
 118 #       define SCM_C_BVEC_POS_MASK     63
 119 #       define SCM_CELL_SIZE_SHIFT     4
 120 #else
 121 #       define SCM_C_BVEC_LONG_BITS    32
 122 #       define SCM_C_BVEC_OFFSET_SHIFT 5
 123 #       define SCM_C_BVEC_POS_MASK     31
 124 #       define SCM_CELL_SIZE_SHIFT     3
 125 #endif
 126
 127 #define SCM_C_BVEC_OFFSET(pos) (pos >> SCM_C_BVEC_OFFSET_SHIFT)
 128
 129 #define SCM_C_BVEC_GET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] & (1L << (pos & SCM_C_BVEC_POS_MASK)))
 130 #define SCM_C_BVEC_SET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] |= (1L << (pos & SCM_C_BVEC_POS_MASK)))
 131 #define SCM_C_BVEC_CLEAR(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] &= ~(1L << (pos & SCM_C_BVEC_POS_MASK)))
 132
 133 /* testing and changing GC marks */
 134 #define SCM_GC_MARK_P(x)   SCM_GC_CELL_GET_BIT (x)
 135 #define SCM_SET_GC_MARK(x) SCM_GC_CELL_SET_BIT (x)
 136 #define SCM_CLEAR_GC_MARK(x) SCM_GC_CELL_CLEAR_BIT (x)
 137
 138 /* Low level cell data accessing macros.  These macros should only be used
 139  * from within code related to garbage collection issues, since they will
 140  * never check the cells they are applied to - not even if guile is compiled
 141  * in debug mode.  In particular these macros will even work for free cells,
 142  * which should never be encountered by user code.  */
 143
 144 #define SCM_GC_CELL_OBJECT(x, n) (((SCM *)SCM2PTR (x)) [n])
 145 #define SCM_GC_CELL_WORD(x, n)   (SCM_UNPACK (SCM_GC_CELL_OBJECT ((x), (n))))
 146
 147 #define SCM_GC_SET_CELL_OBJECT(x, n, v) ((((SCM *)SCM2PTR (x)) [n]) = (v))
 148 #define SCM_GC_SET_CELL_WORD(x, n, v)  \
 149   (SCM_GC_SET_CELL_OBJECT ((x), (n), SCM_PACK (v)))
 150
 151 #define SCM_GC_CELL_TYPE(x) (SCM_GC_CELL_OBJECT ((x), 0))
 152
 153
 154 /* Except for the garbage collector, no part of guile should ever run over a
 155  * free cell.  Thus, if guile is compiled in debug mode the SCM_CELL_* and
 156  * SCM_SET_CELL_* macros below report an error if they are applied to a free
 157  * cell.  Some other plausibility checks are also performed.  However, if
 158  * guile is not compiled in debug mode, there won't be any time penalty at all
 159  * when using these macros.  */
 160
 161 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 162 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
 163 #else
 164 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
 165 #endif
 166
 167 #define SCM_CELL_WORD(x, n) \
 168   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_WORD ((x), (n)))
 169 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD ((x), 0)
 170 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD ((x), 1)
 171 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD ((x), 2)
 172 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD ((x), 3)
 173
 174 #define SCM_CELL_OBJECT(x, n) \
 175   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_OBJECT ((x), (n)))
 176 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT ((x), 0)
 177 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT ((x), 1)
 178 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT ((x), 2)
 179 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT ((x), 3)
 180
 181 #define SCM_SET_CELL_WORD(x, n, v) \
 182   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_WORD ((x), (n), (v)))
 183 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD ((x), 0, (v))
 184 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD ((x), 1, (v))
 185 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD ((x), 2, (v))
 186 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD ((x), 3, (v))
 187
 188 #define SCM_SET_CELL_OBJECT(x, n, v) \
 189   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_OBJECT ((x), (n), (v)))
 190 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT ((x), 0, (v))
 191 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT ((x), 1, (v))
 192 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT ((x), 2, (v))
 193 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT ((x), 3, (v))
 194
 195 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 196 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 ((x), (t))
 197
 198 /* Freelists consist of linked cells where the type entry holds the value
 199  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 200  * the freelist.  Due to this structure, freelist cells are not cons cells
 201  * and thus may not be accessed using SCM_CAR and SCM_CDR.  */
 202
 203 /*
 204   SCM_FREECELL_P removed ; the semantics are ambiguous with lazy
 205   sweeping. Could mean "this cell is no longer in use (will be swept)"
 206   or "this cell has just been swept, and is not yet in use".
 207  */
 208
 209 #define SCM_FREECELL_P  this_macro_has_been_removed_see_gc_header_file
 210
 211 #define SCM_FREE_CELL_CDR(x) \
 212   (SCM_GC_CELL_OBJECT ((x), 1))
 213 #define SCM_SET_FREE_CELL_CDR(x, v) \
 214   (SCM_GC_SET_CELL_OBJECT ((x), 1, (v)))
 215
 216
 217 #define SCM_CELL_OBJECT_LOC(x, n) (&SCM_CELL_OBJECT ((x), (n)))
 218 #define SCM_CARLOC(x)             (SCM_CELL_OBJECT_LOC ((x), 0))
 219 #define SCM_CDRLOC(x)             (SCM_CELL_OBJECT_LOC ((x), 1))
 220
 221
 222
 223
 224 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 225 /* Set this to != 0 if every cell that is accessed shall be checked:
 226  */
 227 SCM_API int scm_debug_cell_accesses_p;
 228 SCM_API int scm_expensive_debug_cell_accesses_p;
 229 SCM_API int scm_debug_cells_gc_interval ;
 230 void scm_i_expensive_validation_check (SCM cell);
 231 #endif
 232
 233 SCM_API int scm_block_gc;
 234 SCM_API int scm_gc_heap_lock;
 235 SCM_API unsigned int scm_gc_running_p;
 236 SCM_API scm_t_rec_mutex scm_i_sweep_mutex;
 237 \f
 238
 239 #if (SCM_ENABLE_DEPRECATED == 1)
 240 SCM_API size_t scm_default_init_heap_size_1;
 241 SCM_API int scm_default_min_yield_1;
 242 SCM_API size_t scm_default_init_heap_size_2;
 243 SCM_API int scm_default_min_yield_2;
 244 SCM_API size_t scm_default_max_segment_size;
 245 #else
 246 #define  scm_default_init_heap_size_1 deprecated
 247 #define  scm_default_min_yield_1 deprecated
 248 #define  scm_default_init_heap_size_2 deprecated
 249 #define  scm_default_min_yield_2 deprecated
 250 #define  scm_default_max_segment_size deprecated
 251 #endif
 252
 253
 254 SCM_API size_t scm_max_segment_size;
 255
 256 #define SCM_FREELIST_CREATE(key)                \
 257   do { SCM *ls = (SCM *) malloc (sizeof (SCM)); \
 258        *ls = SCM_EOL;                           \
 259        scm_setspecific ((key), ls); } while (0)
 260 #define SCM_FREELIST_LOC(key) ((SCM *) scm_getspecific (key))
 261 SCM_API scm_t_key scm_i_freelist;
 262 SCM_API scm_t_key scm_i_freelist2;
 263 SCM_API struct scm_t_cell_type_statistics scm_i_master_freelist;
 264 SCM_API struct scm_t_cell_type_statistics scm_i_master_freelist2;
 265
 266
 267 SCM_API unsigned long scm_gc_cells_swept;
 268 SCM_API unsigned long scm_gc_cells_collected;
 269 SCM_API unsigned long scm_gc_malloc_collected;
 270 SCM_API unsigned long scm_gc_ports_collected;
 271 SCM_API unsigned long scm_cells_allocated;
 272 SCM_API int scm_gc_cell_yield_percentage;
 273 SCM_API int scm_gc_malloc_yield_percentage;
 274 SCM_API unsigned long scm_mallocated;
 275 SCM_API unsigned long scm_mtrigger;
 276
 277
 278
 279 SCM_API SCM scm_after_gc_hook;
 280
 281 SCM_API scm_t_c_hook scm_before_gc_c_hook;
 282 SCM_API scm_t_c_hook scm_before_mark_c_hook;
 283 SCM_API scm_t_c_hook scm_before_sweep_c_hook;
 284 SCM_API scm_t_c_hook scm_after_sweep_c_hook;
 285 SCM_API scm_t_c_hook scm_after_gc_c_hook;
 286
 287 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 288 #if (SCM_ENABLE_DEPRECATED == 1)
 289 SCM scm_map_free_list (void);
 290 #else
 291 #define scm_map_free_list deprecated
 292 #define scm_free_list_length deprecated
 293 #endif
 294 #endif
 295
 296 #if (SCM_ENABLE_DEPRECATED == 1) && defined (GUILE_DEBUG_FREELIST)
 297 SCM_API SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 298 #endif
 299 \f
 300
 301 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 302 SCM_API void scm_assert_cell_valid (SCM);
 303 #endif
 304
 305 SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag);
 306
 307
 308 SCM_API SCM scm_object_address (SCM obj);
 309 SCM_API SCM scm_gc_stats (void);
 310 SCM_API SCM scm_gc (void);
 311 SCM_API void scm_gc_for_alloc (struct scm_t_cell_type_statistics *freelist);
 312 SCM_API SCM scm_gc_for_newcell (struct scm_t_cell_type_statistics *master, SCM *freelist);
 313 SCM_API void scm_igc (const char *what);
 314 SCM_API void scm_gc_mark (SCM p);
 315 SCM_API void scm_gc_mark_dependencies (SCM p);
 316 SCM_API void scm_mark_locations (SCM_STACKITEM x[], unsigned long n);
 317 SCM_API int scm_in_heap_p (SCM value);
 318 SCM_API void scm_gc_sweep (void);
 319
 320 SCM_API void *scm_malloc (size_t size);
 321 SCM_API void *scm_calloc (size_t size);
 322 SCM_API void *scm_realloc (void *mem, size_t size);
 323 SCM_API char *scm_strdup (const char *str);
 324 SCM_API char *scm_strndup (const char *str, size_t n);
 325 SCM_API void scm_gc_register_collectable_memory (void *mem, size_t size,
 326                                                  const char *what);
 327 SCM_API void scm_gc_unregister_collectable_memory (void *mem, size_t size,
 328                                                    const char *what);
 329 SCM_API void *scm_gc_calloc (size_t size, const char *what);
 330 SCM_API void *scm_gc_malloc (size_t size, const char *what);
 331 SCM_API void *scm_gc_realloc (void *mem, size_t old_size,
 332                               size_t new_size, const char *what);
 333 SCM_API void scm_gc_free (void *mem, size_t size, const char *what);
 334 SCM_API char *scm_gc_strdup (const char *str, const char *what);
 335 SCM_API char *scm_gc_strndup (const char *str, size_t n, const char *what);
 336
 337 SCM_API void scm_remember_upto_here_1 (SCM obj);
 338 SCM_API void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 339 SCM_API void scm_remember_upto_here (SCM obj1, ...);
 340
 341 /* In GCC we can force a reference to an SCM by making it an input to an
 342    empty asm.  This avoids the code size and slowdown of an actual function
 343    call.  Unfortunately there doesn't seem to be any way to do the varargs
 344    scm_remember_upto_here like this.
 345
 346    __volatile__ ensures nothing will be moved across the asm, and it won't
 347    be optimized away (or only if proved unreachable).  Constraint "g" can be
 348    used on all processors and allows any memory or general register (or
 349    immediate) operand.  The actual asm syntax doesn't matter, we don't want
 350    to use it, just ensure the operand is still alive.  See "Extended Asm" in
 351    the GCC manual for more.  */
 352
 353 #ifdef __GNUC__
 354 #define scm_remember_upto_here_1(x)             \
 355   do {                                          \
 356     __asm__ __volatile__ ("" : : "g" (x));      \
 357   } while (0)
 358 #define scm_remember_upto_here_2(x, y)          \
 359   do {                                          \
 360     scm_remember_upto_here_1 (x);               \
 361     scm_remember_upto_here_1 (y);               \
 362   } while (0)
 363 #endif
 364
 365 SCM_API SCM scm_return_first (SCM elt, ...);
 366 SCM_API int scm_return_first_int (int x, ...);
 367 SCM_API SCM scm_permanent_object (SCM obj);
 368 SCM_API SCM scm_gc_protect_object (SCM obj);
 369 SCM_API SCM scm_gc_unprotect_object (SCM obj);
 370 SCM_API void scm_gc_register_root (SCM *p);
 371 SCM_API void scm_gc_unregister_root (SCM *p);
 372 SCM_API void scm_gc_register_roots (SCM *b, unsigned long n);
 373 SCM_API void scm_gc_unregister_roots (SCM *b, unsigned long n);
 374 SCM_API void scm_storage_prehistory (void);
 375 SCM_API int scm_init_storage (void);
 376 SCM_API void *scm_get_stack_base (void);
 377 SCM_API void scm_init_gc (void);
 378
 379 #if SCM_ENABLE_DEPRECATED == 1
 380
 381 SCM_API SCM scm_deprecated_newcell (void);
 382 SCM_API SCM scm_deprecated_newcell2 (void);
 383
 384 #define SCM_NEWCELL(_into) \
 385   do { _into = scm_deprecated_newcell (); } while (0)
 386 #define SCM_NEWCELL2(_into) \
 387   do { _into = scm_deprecated_newcell2 (); } while (0)
 388
 389 SCM_API void * scm_must_malloc (size_t len, const char *what);
 390 SCM_API void * scm_must_realloc (void *where,
 391                                  size_t olen, size_t len,
 392                                  const char *what);
 393 SCM_API char *scm_must_strdup (const char *str);
 394 SCM_API char *scm_must_strndup (const char *str, size_t n);
 395 SCM_API void scm_done_malloc (long size);
 396 SCM_API void scm_done_free (long size);
 397 SCM_API void scm_must_free (void *obj);
 398
 399 #endif
 400
 401 #endif  /* SCM_GC_H */
 402
 403 /*
 404   Local Variables:
 405   c-file-style: "gnu"
 406   End:
 407 */