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 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_t_bits word_0;
  40   scm_t_bits 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 efficiently: we
  49   knock off some lowerorder bits.
  50
  51   The size on a 32 bit machine is 256 cells = 2kb. The card
  52 */
  53
  54
  55
  56 /* Cray machines have pointers that are incremented once for each word,
  57  * rather than each byte, the 3 most significant bits encode the byte
  58  * within the word.  The following macros deal with this by storing the
  59  * native Cray pointers like the ones that looks like scm expects.  This
  60  * is done for any pointers that might appear in the car of a scm_t_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_t_bits) (bvec))
  79
  80
  81 #define SCM_GC_GET_CARD_FLAGS(card) ((long) ((card)->word_1))
  82 #define SCM_GC_SET_CARD_FLAGS(card, flags) \
  83     ((card)->word_1 = (scm_t_bits) (flags))
  84 #define SCM_GC_CLEAR_CARD_FLAGS(card) (SCM_GC_SET_CARD_FLAGS (card, 0L))
  85
  86 #define SCM_GC_GET_CARD_FLAG(card, shift) (SCM_GC_GET_CARD_FLAGS (card) & (1L << (shift)))
  87 #define SCM_GC_SET_CARD_FLAG(card, shift) \
  88     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) | (1L << (shift))))
  89 #define SCM_GC_CLEAR_CARD_FLAG(card, shift) \
  90     (SCM_GC_SET_CARD_FLAGS (card, SCM_GC_GET_CARD_FLAGS(card) & ~(1L << (shift))))
  91
  92 /*
  93   Remove card flags. They hamper lazy initialization, and aren't used
  94   anyways.
  95  */
  96
  97 /* card addressing. for efficiency, cards are *always* aligned to
  98    SCM_GC_CARD_SIZE. */
  99
 100 #define SCM_GC_CARD_SIZE_MASK  (SCM_GC_CARD_N_CELLS * sizeof (scm_t_cell) - 1)
 101 #define SCM_GC_CARD_ADDR_MASK  (~SCM_GC_CARD_SIZE_MASK)
 102
 103 #define SCM_GC_CELL_CARD(x)    ((scm_t_cell *) ((long) (x) & SCM_GC_CARD_ADDR_MASK))
 104 #define SCM_GC_CELL_OFFSET(x)  (((long) (x) & SCM_GC_CARD_SIZE_MASK) >> SCM_CELL_SIZE_SHIFT)
 105 #define SCM_GC_CELL_BVEC(x)    SCM_GC_CARD_BVEC (SCM_GC_CELL_CARD (x))
 106 #define SCM_GC_SET_CELL_BVEC(x, bvec)    SCM_GC_SET_CARD_BVEC (SCM_GC_CELL_CARD (x), bvec)
 107 #define SCM_GC_CELL_GET_BIT(x) SCM_C_BVEC_GET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 108 #define SCM_GC_CELL_SET_BIT(x) SCM_C_BVEC_SET (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 109 #define SCM_GC_CELL_CLEAR_BIT(x) SCM_C_BVEC_CLEAR (SCM_GC_CELL_BVEC (x), SCM_GC_CELL_OFFSET (x))
 110
 111 #define SCM_GC_CARD_UP(x)      SCM_GC_CELL_CARD ((char *) (x) + SCM_GC_SIZEOF_CARD - 1)
 112 #define SCM_GC_CARD_DOWN       SCM_GC_CELL_CARD
 113
 114 /* low level bit banging aids */
 115 typedef unsigned long scm_t_c_bvec_long;
 116
 117 #if (SCM_SIZEOF_UNSIGNED_LONG == 8)
 118 #       define SCM_C_BVEC_LONG_BITS    64
 119 #       define SCM_C_BVEC_OFFSET_SHIFT 6
 120 #       define SCM_C_BVEC_POS_MASK     63
 121 #       define SCM_CELL_SIZE_SHIFT     4
 122 #else
 123 #       define SCM_C_BVEC_LONG_BITS    32
 124 #       define SCM_C_BVEC_OFFSET_SHIFT 5
 125 #       define SCM_C_BVEC_POS_MASK     31
 126 #       define SCM_CELL_SIZE_SHIFT     3
 127 #endif
 128
 129 #define SCM_C_BVEC_OFFSET(pos) (pos >> SCM_C_BVEC_OFFSET_SHIFT)
 130
 131 #define SCM_C_BVEC_GET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] & (1L << (pos & SCM_C_BVEC_POS_MASK)))
 132 #define SCM_C_BVEC_SET(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] |= (1L << (pos & SCM_C_BVEC_POS_MASK)))
 133 #define SCM_C_BVEC_CLEAR(bvec, pos) (bvec[SCM_C_BVEC_OFFSET (pos)] &= ~(1L << (pos & SCM_C_BVEC_POS_MASK)))
 134
 135 /* testing and changing GC marks */
 136 #define SCM_GC_MARK_P(x)   SCM_GC_CELL_GET_BIT (x)
 137 #define SCM_SET_GC_MARK(x) SCM_GC_CELL_SET_BIT (x)
 138 #define SCM_CLEAR_GC_MARK(x) SCM_GC_CELL_CLEAR_BIT (x)
 139
 140 /* Low level cell data accessing macros.  These macros should only be used
 141  * from within code related to garbage collection issues, since they will
 142  * never check the cells they are applied to - not even if guile is compiled
 143  * in debug mode.  In particular these macros will even work for free cells,
 144  * which should never be encountered by user code.  */
 145
 146 #define SCM_GC_CELL_WORD(x, n) \
 147   (((const scm_t_bits *) SCM2PTR (x)) [n])
 148 #define SCM_GC_CELL_OBJECT(x, n) \
 149   (SCM_PACK (((const scm_t_bits *) SCM2PTR (x)) [n]))
 150 #define SCM_GC_SET_CELL_WORD(x, n, v) \
 151   (((scm_t_bits *) SCM2PTR (x)) [n] = (scm_t_bits) (v))
 152 #define SCM_GC_SET_CELL_OBJECT(x, n, v) \
 153  (((scm_t_bits *) SCM2PTR (x)) [n] = SCM_UNPACK (v))
 154 #define SCM_GC_CELL_TYPE(x) SCM_GC_CELL_WORD (x, 0)
 155
 156
 157 /* Except for the garbage collector, no part of guile should ever run over a
 158  * free cell.  Thus, if guile is compiled in debug mode the SCM_CELL_* and
 159  * SCM_SET_CELL_* macros below report an error if they are applied to a free
 160  * cell.  Some other plausibility checks are also performed.  However, if
 161  * guile is not compiled in debug mode, there won't be any time penalty at all
 162  * when using these macros.  */
 163
 164 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 165 #  define SCM_VALIDATE_CELL(cell, expr) (scm_assert_cell_valid (cell), (expr))
 166 #else
 167 #  define SCM_VALIDATE_CELL(cell, expr) (expr)
 168 #endif
 169
 170 #define SCM_CELL_WORD(x, n) \
 171   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_WORD ((x), (n)))
 172 #define SCM_CELL_WORD_0(x) SCM_CELL_WORD (x, 0)
 173 #define SCM_CELL_WORD_1(x) SCM_CELL_WORD (x, 1)
 174 #define SCM_CELL_WORD_2(x) SCM_CELL_WORD (x, 2)
 175 #define SCM_CELL_WORD_3(x) SCM_CELL_WORD (x, 3)
 176
 177 #define SCM_CELL_OBJECT(x, n) \
 178   SCM_VALIDATE_CELL ((x), SCM_GC_CELL_OBJECT ((x), (n)))
 179 #define SCM_CELL_OBJECT_0(x) SCM_CELL_OBJECT (x, 0)
 180 #define SCM_CELL_OBJECT_1(x) SCM_CELL_OBJECT (x, 1)
 181 #define SCM_CELL_OBJECT_2(x) SCM_CELL_OBJECT (x, 2)
 182 #define SCM_CELL_OBJECT_3(x) SCM_CELL_OBJECT (x, 3)
 183
 184 #define SCM_SET_CELL_WORD(x, n, v) \
 185   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_WORD ((x), (n), (v)))
 186 #define SCM_SET_CELL_WORD_0(x, v) SCM_SET_CELL_WORD (x, 0, v)
 187 #define SCM_SET_CELL_WORD_1(x, v) SCM_SET_CELL_WORD (x, 1, v)
 188 #define SCM_SET_CELL_WORD_2(x, v) SCM_SET_CELL_WORD (x, 2, v)
 189 #define SCM_SET_CELL_WORD_3(x, v) SCM_SET_CELL_WORD (x, 3, v)
 190
 191 #define SCM_SET_CELL_OBJECT(x, n, v) \
 192   SCM_VALIDATE_CELL ((x), SCM_GC_SET_CELL_OBJECT ((x), (n), (v)))
 193 #define SCM_SET_CELL_OBJECT_0(x, v) SCM_SET_CELL_OBJECT (x, 0, v)
 194 #define SCM_SET_CELL_OBJECT_1(x, v) SCM_SET_CELL_OBJECT (x, 1, v)
 195 #define SCM_SET_CELL_OBJECT_2(x, v) SCM_SET_CELL_OBJECT (x, 2, v)
 196 #define SCM_SET_CELL_OBJECT_3(x, v) SCM_SET_CELL_OBJECT (x, 3, v)
 197
 198 #define SCM_CELL_TYPE(x) SCM_CELL_WORD_0 (x)
 199 #define SCM_SET_CELL_TYPE(x, t) SCM_SET_CELL_WORD_0 (x, t)
 200
 201 /* Freelists consist of linked cells where the type entry holds the value
 202  * scm_tc_free_cell and the second entry holds a pointer to the next cell of
 203  * the freelist.  Due to this structure, freelist cells are not cons cells
 204  * and thus may not be accessed using SCM_CAR and SCM_CDR.  */
 205
 206 /*
 207   SCM_FREECELL_P removed ; the semantics are ambiguous with lazy
 208   sweeping. Could mean "this cell is no longer in use (will be swept)"
 209   or "this cell has just been swept, and is not yet in use".
 210  */
 211
 212 #define SCM_FREECELL_P  this_macro_has_been_removed_see_gc_header_file
 213
 214 #define SCM_FREE_CELL_CDR(x) \
 215   (SCM_GC_CELL_OBJECT ((x), 1))
 216 #define SCM_SET_FREE_CELL_CDR(x, v) \
 217   (SCM_GC_SET_CELL_OBJECT ((x), 1, (v)))
 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
 226
 227 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 228 /* Set this to != 0 if every cell that is accessed shall be checked:
 229  */
 230 SCM_API int scm_debug_cell_accesses_p;
 231 SCM_API int scm_expensive_debug_cell_accesses_p;
 232 SCM_API int scm_debug_cells_gc_interval ;
 233 void scm_i_expensive_validation_check (SCM cell);
 234 #endif
 235
 236 SCM_API int scm_block_gc;
 237 SCM_API int scm_gc_heap_lock;
 238 SCM_API unsigned int scm_gc_running_p;
 239 SCM_API scm_t_rec_mutex scm_i_sweep_mutex;
 240 \f
 241
 242 #if (SCM_ENABLE_DEPRECATED == 1)
 243 SCM_API size_t scm_default_init_heap_size_1;
 244 SCM_API int scm_default_min_yield_1;
 245 SCM_API size_t scm_default_init_heap_size_2;
 246 SCM_API int scm_default_min_yield_2;
 247 SCM_API size_t scm_default_max_segment_size;
 248 #else
 249 #define  scm_default_init_heap_size_1 deprecated
 250 #define  scm_default_min_yield_1 deprecated
 251 #define  scm_default_init_heap_size_2 deprecated
 252 #define  scm_default_min_yield_2 deprecated
 253 #define  scm_default_max_segment_size deprecated
 254 #endif
 255
 256
 257 SCM_API size_t scm_max_segment_size;
 258
 259 #define SCM_FREELIST_CREATE(key)                \
 260   do { SCM *ls = (SCM *) malloc (sizeof (SCM)); \
 261        *ls = SCM_EOL;                           \
 262        scm_setspecific ((key), ls); } while (0)
 263 #define SCM_FREELIST_LOC(key) ((SCM *) scm_getspecific (key))
 264 SCM_API scm_t_key scm_i_freelist;
 265 SCM_API scm_t_key scm_i_freelist2;
 266 SCM_API struct scm_t_cell_type_statistics scm_i_master_freelist;
 267 SCM_API struct scm_t_cell_type_statistics scm_i_master_freelist2;
 268
 269
 270 SCM_API unsigned long scm_gc_cells_swept;
 271 SCM_API unsigned long scm_gc_cells_collected;
 272 SCM_API unsigned long scm_gc_cells_collected;
 273 SCM_API unsigned long scm_gc_malloc_collected;
 274 SCM_API unsigned long scm_gc_ports_collected;
 275 SCM_API unsigned long scm_cells_allocated;
 276 SCM_API int scm_gc_cell_yield_percentage;
 277 SCM_API int scm_gc_malloc_yield_percentage;
 278 SCM_API unsigned long scm_mallocated;
 279 SCM_API unsigned long scm_mtrigger;
 280
 281
 282
 283 SCM_API SCM scm_after_gc_hook;
 284
 285 SCM_API scm_t_c_hook scm_before_gc_c_hook;
 286 SCM_API scm_t_c_hook scm_before_mark_c_hook;
 287 SCM_API scm_t_c_hook scm_before_sweep_c_hook;
 288 SCM_API scm_t_c_hook scm_after_sweep_c_hook;
 289 SCM_API scm_t_c_hook scm_after_gc_c_hook;
 290
 291 #if defined (GUILE_DEBUG) || defined (GUILE_DEBUG_FREELIST)
 292 #if (SCM_ENABLE_DEPRECATED == 1)
 293 SCM scm_map_free_list (void);
 294 #else
 295 #define scm_map_free_list deprecated
 296 #define scm_free_list_length deprecated
 297 #endif
 298 #endif
 299
 300 #if (SCM_ENABLE_DEPRECATED == 1) && defined (GUILE_DEBUG_FREELIST)
 301 SCM_API SCM scm_gc_set_debug_check_freelist_x (SCM flag);
 302 #endif
 303 \f
 304
 305 #if (SCM_DEBUG_CELL_ACCESSES == 1)
 306 SCM_API void scm_assert_cell_valid (SCM);
 307 #endif
 308
 309 SCM_API SCM scm_set_debug_cell_accesses_x (SCM flag);
 310
 311
 312 SCM_API SCM scm_object_address (SCM obj);
 313 SCM_API SCM scm_gc_stats (void);
 314 SCM_API SCM scm_gc (void);
 315 SCM_API void scm_gc_for_alloc (struct scm_t_cell_type_statistics *freelist);
 316 SCM_API SCM scm_gc_for_newcell (struct scm_t_cell_type_statistics *master, SCM *freelist);
 317 SCM_API void scm_igc (const char *what);
 318 SCM_API void scm_gc_mark (SCM p);
 319 SCM_API void scm_gc_mark_dependencies (SCM p);
 320 SCM_API void scm_mark_locations (SCM_STACKITEM x[], unsigned long n);
 321 SCM_API int scm_in_heap_p (SCM value);
 322 SCM_API void scm_gc_sweep (void);
 323
 324 SCM_API void *scm_malloc (size_t size);
 325 SCM_API void *scm_calloc (size_t size);
 326 SCM_API void *scm_realloc (void *mem, size_t size);
 327 SCM_API char *scm_strdup (const char *str);
 328 SCM_API char *scm_strndup (const char *str, size_t n);
 329 SCM_API void scm_gc_register_collectable_memory (void *mem, size_t size,
 330                                                  const char *what);
 331 SCM_API void scm_gc_unregister_collectable_memory (void *mem, size_t size,
 332                                                    const char *what);
 333 SCM_API void *scm_gc_calloc (size_t size, const char *what);
 334 SCM_API void *scm_gc_malloc (size_t size, const char *what);
 335 SCM_API void *scm_gc_realloc (void *mem, size_t old_size,
 336                               size_t new_size, const char *what);
 337 SCM_API void scm_gc_free (void *mem, size_t size, const char *what);
 338 SCM_API char *scm_gc_strdup (const char *str, const char *what);
 339 SCM_API char *scm_gc_strndup (const char *str, size_t n, const char *what);
 340
 341 SCM_API void scm_remember_upto_here_1 (SCM obj);
 342 SCM_API void scm_remember_upto_here_2 (SCM obj1, SCM obj2);
 343 SCM_API void scm_remember_upto_here (SCM obj1, ...);
 344
 345 /* In GCC we can force a reference to an SCM by making it an input to an
 346    empty asm.  This avoids the code size and slowdown of an actual function
 347    call.  Unfortunately there doesn't seem to be any way to do the varargs
 348    scm_remember_upto_here like this.
 349
 350    __volatile__ ensures nothing will be moved across the asm, and it won't
 351    be optimized away (or only if proved unreachable).  Constraint "g" can be
 352    used on all processors and allows any memory or general register (or
 353    immediate) operand.  The actual asm syntax doesn't matter, we don't want
 354    to use it, just ensure the operand is still alive.  See "Extended Asm" in
 355    the GCC manual for more.  */
 356
 357 #ifdef __GNUC__
 358 #define scm_remember_upto_here_1(x)             \
 359   do {                                          \
 360     __asm__ __volatile__ ("" : : "g" (x));      \
 361   } while (0)
 362 #define scm_remember_upto_here_2(x, y)          \
 363   do {                                          \
 364     scm_remember_upto_here_1 (x);               \
 365     scm_remember_upto_here_1 (y);               \
 366   } while (0)
 367 #endif
 368
 369 SCM_API SCM scm_return_first (SCM elt, ...);
 370 SCM_API int scm_return_first_int (int x, ...);
 371 SCM_API SCM scm_permanent_object (SCM obj);
 372 SCM_API SCM scm_gc_protect_object (SCM obj);
 373 SCM_API SCM scm_gc_unprotect_object (SCM obj);
 374 SCM_API void scm_gc_register_root (SCM *p);
 375 SCM_API void scm_gc_unregister_root (SCM *p);
 376 SCM_API void scm_gc_register_roots (SCM *b, unsigned long n);
 377 SCM_API void scm_gc_unregister_roots (SCM *b, unsigned long n);
 378 SCM_API void scm_storage_prehistory (void);
 379 SCM_API int scm_init_storage (void);
 380 SCM_API void *scm_get_stack_base (void);
 381 SCM_API void scm_init_gc (void);
 382
 383 #if SCM_ENABLE_DEPRECATED == 1
 384
 385 SCM_API SCM scm_deprecated_newcell (void);
 386 SCM_API SCM scm_deprecated_newcell2 (void);
 387
 388 #define SCM_NEWCELL(_into) \
 389   do { _into = scm_deprecated_newcell (); } while (0)
 390 #define SCM_NEWCELL2(_into) \
 391   do { _into = scm_deprecated_newcell2 (); } while (0)
 392
 393 SCM_API void * scm_must_malloc (size_t len, const char *what);
 394 SCM_API void * scm_must_realloc (void *where,
 395                                  size_t olen, size_t len,
 396                                  const char *what);
 397 SCM_API char *scm_must_strdup (const char *str);
 398 SCM_API char *scm_must_strndup (const char *str, size_t n);
 399 SCM_API void scm_done_malloc (long size);
 400 SCM_API void scm_done_free (long size);
 401 SCM_API void scm_must_free (void *obj);
 402
 403 #endif
 404
 405 #endif  /* SCM_GC_H */
 406
 407 /*
 408   Local Variables:
 409   c-file-style: "gnu"
 410   End:
 411 */