1 /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 2006, 2008, 2009 Free Software Foundation, Inc.
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public License
5 * as published by the Free Software Foundation; either version 3 of
6 * the License, or (at your option) any later version.
8 * This library is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 /* #define DEBUGINFO */
30 #include "libguile/_scm.h"
31 #include "libguile/eval.h"
32 #include "libguile/stime.h"
33 #include "libguile/stackchk.h"
34 #include "libguile/struct.h"
35 #include "libguile/smob.h"
36 #include "libguile/arrays.h"
37 #include "libguile/async.h"
38 #include "libguile/ports.h"
39 #include "libguile/root.h"
40 #include "libguile/strings.h"
41 #include "libguile/vectors.h"
42 #include "libguile/weaks.h"
43 #include "libguile/hashtab.h"
44 #include "libguile/tags.h"
46 #include "libguile/private-gc.h"
47 #include "libguile/validate.h"
48 #include "libguile/deprecation.h"
49 #include "libguile/gc.h"
50 #include "libguile/dynwind.h"
52 #ifdef GUILE_DEBUG_MALLOC
53 #include "libguile/debug-malloc.h"
64 /* Lock this mutex before doing lazy sweeping.
66 scm_i_pthread_mutex_t scm_i_sweep_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
68 /* Set this to != 0 if every cell that is accessed shall be checked:
70 int scm_debug_cell_accesses_p
= 0;
71 int scm_expensive_debug_cell_accesses_p
= 0;
73 /* Set this to 0 if no additional gc's shall be performed, otherwise set it to
74 * the number of cell accesses after which a gc shall be called.
76 int scm_debug_cells_gc_interval
= 0;
79 Global variable, so you can switch it off at runtime by setting
80 scm_i_cell_validation_already_running.
82 int scm_i_cell_validation_already_running
;
84 #if (SCM_DEBUG_CELL_ACCESSES == 1)
89 Assert that the given object is a valid reference to a valid cell. This
90 test involves to determine whether the object is a cell pointer, whether
91 this pointer actually points into a heap segment and whether the cell
92 pointed to is not a free cell. Further, additional garbage collections may
93 get executed after a user defined number of cell accesses. This helps to
94 find places in the C code where references are dropped for extremely short
99 scm_i_expensive_validation_check (SCM cell
)
101 if (!scm_in_heap_p (cell
))
103 fprintf (stderr
, "scm_assert_cell_valid: this object does not live in the heap: %lux\n",
104 (unsigned long) SCM_UNPACK (cell
));
108 /* If desired, perform additional garbage collections after a user
109 * defined number of cell accesses.
111 if (scm_debug_cells_gc_interval
)
113 static unsigned int counter
= 0;
121 counter
= scm_debug_cells_gc_interval
;
128 scm_assert_cell_valid (SCM cell
)
130 if (!scm_i_cell_validation_already_running
&& scm_debug_cell_accesses_p
)
132 scm_i_cell_validation_already_running
= 1; /* set to avoid recursion */
135 During GC, no user-code should be run, and the guile core
136 should use non-protected accessors.
138 if (scm_gc_running_p
)
142 Only scm_in_heap_p and rescanning the heap is wildly
145 if (scm_expensive_debug_cell_accesses_p
)
146 scm_i_expensive_validation_check (cell
);
147 #if (SCM_DEBUG_MARKING_API == 0)
148 if (!SCM_GC_MARK_P (cell
))
151 "scm_assert_cell_valid: this object is unmarked. \n"
152 "It has been garbage-collected in the last GC run: "
154 (unsigned long) SCM_UNPACK (cell
));
157 #endif /* SCM_DEBUG_MARKING_API */
159 scm_i_cell_validation_already_running
= 0; /* re-enable */
165 SCM_DEFINE (scm_set_debug_cell_accesses_x
, "set-debug-cell-accesses!", 1, 0, 0,
167 "If @var{flag} is @code{#f}, cell access checking is disabled.\n"
168 "If @var{flag} is @code{#t}, cheap cell access checking is enabled,\n"
169 "but no additional calls to garbage collection are issued.\n"
170 "If @var{flag} is a number, strict cell access checking is enabled,\n"
171 "with an additional garbage collection after the given\n"
172 "number of cell accesses.\n"
173 "This procedure only exists when the compile-time flag\n"
174 "@code{SCM_DEBUG_CELL_ACCESSES} was set to 1.")
175 #define FUNC_NAME s_scm_set_debug_cell_accesses_x
177 if (scm_is_false (flag
))
179 scm_debug_cell_accesses_p
= 0;
181 else if (scm_is_eq (flag
, SCM_BOOL_T
))
183 scm_debug_cells_gc_interval
= 0;
184 scm_debug_cell_accesses_p
= 1;
185 scm_expensive_debug_cell_accesses_p
= 0;
189 scm_debug_cells_gc_interval
= scm_to_signed_integer (flag
, 0, INT_MAX
);
190 scm_debug_cell_accesses_p
= 1;
191 scm_expensive_debug_cell_accesses_p
= 1;
193 return SCM_UNSPECIFIED
;
198 #endif /* SCM_DEBUG_CELL_ACCESSES == 1 */
204 * is the number of bytes of malloc allocation needed to trigger gc.
206 unsigned long scm_mtrigger
;
208 /* GC Statistics Keeping
210 unsigned long scm_cells_allocated
= 0;
211 unsigned long scm_last_cells_allocated
= 0;
212 unsigned long scm_mallocated
= 0;
213 long int scm_i_find_heap_calls
= 0;
214 /* Global GC sweep statistics since the last full GC. */
215 scm_t_sweep_statistics scm_i_gc_sweep_stats
= { 0, 0 };
217 /* Total count of cells marked/swept. */
218 static double scm_gc_cells_marked_acc
= 0.;
219 static double scm_gc_cells_marked_conservatively_acc
= 0.;
220 static double scm_gc_cells_swept_acc
= 0.;
221 static double scm_gc_cells_allocated_acc
= 0.;
223 static unsigned long scm_gc_time_taken
= 0;
224 static unsigned long scm_gc_mark_time_taken
= 0;
226 static unsigned long scm_gc_times
= 0;
228 static int scm_gc_cell_yield_percentage
= 0;
229 static unsigned long protected_obj_count
= 0;
231 /* The following are accessed from `gc-malloc.c' and `gc-card.c'. */
232 int scm_gc_malloc_yield_percentage
= 0;
233 unsigned long scm_gc_malloc_collected
= 0;
236 SCM_SYMBOL (sym_cells_allocated
, "cells-allocated");
237 SCM_SYMBOL (sym_heap_size
, "cell-heap-size");
238 SCM_SYMBOL (sym_mallocated
, "bytes-malloced");
239 SCM_SYMBOL (sym_mtrigger
, "gc-malloc-threshold");
240 SCM_SYMBOL (sym_heap_segments
, "cell-heap-segments");
241 SCM_SYMBOL (sym_gc_time_taken
, "gc-time-taken");
242 SCM_SYMBOL (sym_gc_mark_time_taken
, "gc-mark-time-taken");
243 SCM_SYMBOL (sym_times
, "gc-times");
244 SCM_SYMBOL (sym_cells_marked
, "cells-marked");
245 SCM_SYMBOL (sym_cells_marked_conservatively
, "cells-marked-conservatively");
246 SCM_SYMBOL (sym_cells_swept
, "cells-swept");
247 SCM_SYMBOL (sym_malloc_yield
, "malloc-yield");
248 SCM_SYMBOL (sym_cell_yield
, "cell-yield");
249 SCM_SYMBOL (sym_protected_objects
, "protected-objects");
250 SCM_SYMBOL (sym_total_cells_allocated
, "total-cells-allocated");
253 /* Number of calls to SCM_NEWCELL since startup. */
254 unsigned scm_newcell_count
;
255 unsigned scm_newcell2_count
;
258 /* {Scheme Interface to GC}
261 tag_table_to_type_alist (void *closure
, SCM key
, SCM val
, SCM acc
)
263 if (scm_is_integer (key
))
265 int c_tag
= scm_to_int (key
);
267 char const * name
= scm_i_tag_name (c_tag
);
270 key
= scm_from_locale_string (name
);
275 sprintf (s
, "tag %d", c_tag
);
276 key
= scm_from_locale_string (s
);
280 return scm_cons (scm_cons (key
, val
), acc
);
283 SCM_DEFINE (scm_gc_live_object_stats
, "gc-live-object-stats", 0, 0, 0,
285 "Return an alist of statistics of the current live objects. ")
286 #define FUNC_NAME s_scm_gc_live_object_stats
288 SCM tab
= scm_make_hash_table (scm_from_int (57));
291 scm_i_all_segments_statistics (tab
);
294 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
300 extern int scm_gc_malloc_yield_percentage
;
301 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
303 "Return an association list of statistics about Guile's current\n"
305 #define FUNC_NAME s_scm_gc_stats
308 SCM heap_segs
= SCM_EOL
;
309 unsigned long int local_scm_mtrigger
;
310 unsigned long int local_scm_mallocated
;
311 unsigned long int local_scm_heap_size
;
312 int local_scm_gc_cell_yield_percentage
;
313 int local_scm_gc_malloc_yield_percentage
;
314 unsigned long int local_scm_cells_allocated
;
315 unsigned long int local_scm_gc_time_taken
;
316 unsigned long int local_scm_gc_times
;
317 unsigned long int local_scm_gc_mark_time_taken
;
318 unsigned long int local_protected_obj_count
;
319 double local_scm_gc_cells_swept
;
320 double local_scm_gc_cells_marked
;
321 double local_scm_gc_cells_marked_conservatively
;
322 double local_scm_total_cells_allocated
;
324 unsigned long *bounds
= 0;
326 SCM_CRITICAL_SECTION_START
;
328 bounds
= scm_i_segment_table_info (&table_size
);
330 /* Below, we cons to produce the resulting list. We want a snapshot of
331 * the heap situation before consing.
333 local_scm_mtrigger
= scm_mtrigger
;
334 local_scm_mallocated
= scm_mallocated
;
335 local_scm_heap_size
=
336 (scm_i_master_freelist
.heap_total_cells
+ scm_i_master_freelist2
.heap_total_cells
);
338 local_scm_cells_allocated
=
339 scm_cells_allocated
+ scm_i_gc_sweep_stats
.collected
;
341 local_scm_gc_time_taken
= scm_gc_time_taken
;
342 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
343 local_scm_gc_times
= scm_gc_times
;
344 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
345 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
346 local_protected_obj_count
= protected_obj_count
;
347 local_scm_gc_cells_swept
=
348 (double) scm_gc_cells_swept_acc
349 + (double) scm_i_gc_sweep_stats
.swept
;
350 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
351 + (double) scm_i_gc_sweep_stats
.swept
352 - (double) scm_i_gc_sweep_stats
.collected
;
353 local_scm_gc_cells_marked_conservatively
354 = scm_gc_cells_marked_conservatively_acc
;
356 local_scm_total_cells_allocated
= scm_gc_cells_allocated_acc
357 + (double) scm_i_gc_sweep_stats
.collected
;
359 for (i
= table_size
; i
--;)
361 heap_segs
= scm_cons (scm_cons (scm_from_ulong (bounds
[2*i
]),
362 scm_from_ulong (bounds
[2*i
+1])),
366 /* njrev: can any of these scm_cons's or scm_list_n signal a memory
367 error? If so we need a frame here. */
369 scm_list_n (scm_cons (sym_gc_time_taken
,
370 scm_from_ulong (local_scm_gc_time_taken
)),
371 scm_cons (sym_cells_allocated
,
372 scm_from_ulong (local_scm_cells_allocated
)),
373 scm_cons (sym_total_cells_allocated
,
374 scm_from_double (local_scm_total_cells_allocated
)),
375 scm_cons (sym_heap_size
,
376 scm_from_ulong (local_scm_heap_size
)),
377 scm_cons (sym_cells_marked_conservatively
,
378 scm_from_ulong (local_scm_gc_cells_marked_conservatively
)),
379 scm_cons (sym_mallocated
,
380 scm_from_ulong (local_scm_mallocated
)),
381 scm_cons (sym_mtrigger
,
382 scm_from_ulong (local_scm_mtrigger
)),
384 scm_from_ulong (local_scm_gc_times
)),
385 scm_cons (sym_gc_mark_time_taken
,
386 scm_from_ulong (local_scm_gc_mark_time_taken
)),
387 scm_cons (sym_cells_marked
,
388 scm_from_double (local_scm_gc_cells_marked
)),
389 scm_cons (sym_cells_swept
,
390 scm_from_double (local_scm_gc_cells_swept
)),
391 scm_cons (sym_malloc_yield
,
392 scm_from_long (local_scm_gc_malloc_yield_percentage
)),
393 scm_cons (sym_cell_yield
,
394 scm_from_long (local_scm_gc_cell_yield_percentage
)),
395 scm_cons (sym_protected_objects
,
396 scm_from_ulong (local_protected_obj_count
)),
397 scm_cons (sym_heap_segments
, heap_segs
),
399 SCM_CRITICAL_SECTION_END
;
407 Update nice-to-know-statistics.
412 /* CELLS SWEPT is another word for the number of cells that were examined
413 during GC. YIELD is the number that we cleaned out. MARKED is the number
414 that weren't cleaned. */
415 scm_gc_cell_yield_percentage
= (scm_i_gc_sweep_stats
.collected
* 100) /
416 (scm_i_master_freelist
.heap_total_cells
+ scm_i_master_freelist2
.heap_total_cells
);
418 scm_gc_cells_allocated_acc
+=
419 (double) scm_i_gc_sweep_stats
.collected
;
420 scm_gc_cells_marked_acc
+= (double) scm_i_last_marked_cell_count
;
421 scm_gc_cells_marked_conservatively_acc
+= (double) scm_i_find_heap_calls
;
422 scm_gc_cells_swept_acc
+= (double) scm_i_gc_sweep_stats
.swept
;
427 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
429 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
430 "returned by this function for @var{obj}")
431 #define FUNC_NAME s_scm_object_address
433 return scm_from_ulong (SCM_UNPACK (obj
));
438 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
440 "Scans all of SCM objects and reclaims for further use those that are\n"
441 "no longer accessible.")
442 #define FUNC_NAME s_scm_gc
444 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
445 scm_gc_running_p
= 1;
447 /* njrev: It looks as though other places, e.g. scm_realloc,
448 can call scm_i_gc without acquiring the sweep mutex. Does this
449 matter? Also scm_i_gc (or its descendants) touch the
450 scm_sys_protects, which are protected in some cases
451 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
452 not by the sweep mutex. Shouldn't all the GC-relevant objects be
453 protected in the same way? */
454 scm_gc_running_p
= 0;
455 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
456 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
457 return SCM_UNSPECIFIED
;
464 /* The master is global and common while the freelist will be
465 * individual for each thread.
469 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
474 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
475 scm_gc_running_p
= 1;
477 *free_cells
= scm_i_sweep_for_freelist (freelist
);
478 if (*free_cells
== SCM_EOL
)
480 float delta
= scm_i_gc_heap_size_delta (freelist
);
483 size_t bytes
= ((unsigned long) delta
) * sizeof (scm_t_cell
);
484 freelist
->heap_segment_idx
=
485 scm_i_get_new_heap_segment (freelist
, bytes
, abort_on_error
);
487 *free_cells
= scm_i_sweep_for_freelist (freelist
);
491 if (*free_cells
== SCM_EOL
)
494 out of fresh cells. Try to get some new ones.
496 char reason
[] = "0-cells";
497 reason
[0] += freelist
->span
;
502 *free_cells
= scm_i_sweep_for_freelist (freelist
);
505 if (*free_cells
== SCM_EOL
)
508 failed getting new cells. Get new juice or die.
510 float delta
= scm_i_gc_heap_size_delta (freelist
);
511 assert (delta
> 0.0);
512 size_t bytes
= ((unsigned long) delta
) * sizeof (scm_t_cell
);
513 freelist
->heap_segment_idx
=
514 scm_i_get_new_heap_segment (freelist
, bytes
, abort_on_error
);
516 *free_cells
= scm_i_sweep_for_freelist (freelist
);
519 if (*free_cells
== SCM_EOL
)
524 *free_cells
= SCM_FREE_CELL_CDR (cell
);
526 scm_gc_running_p
= 0;
527 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
530 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
536 scm_t_c_hook scm_before_gc_c_hook
;
537 scm_t_c_hook scm_before_mark_c_hook
;
538 scm_t_c_hook scm_before_sweep_c_hook
;
539 scm_t_c_hook scm_after_sweep_c_hook
;
540 scm_t_c_hook scm_after_gc_c_hook
;
543 scm_check_deprecated_memory_return ()
545 if (scm_mallocated
< scm_i_deprecated_memory_return
)
547 /* The byte count of allocated objects has underflowed. This is
548 probably because you forgot to report the sizes of objects you
549 have allocated, by calling scm_done_malloc or some such. When
550 the GC freed them, it subtracted their size from
551 scm_mallocated, which underflowed. */
553 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
554 "This is probably because the GC hasn't been correctly informed\n"
555 "about object sizes\n");
558 scm_mallocated
-= scm_i_deprecated_memory_return
;
559 scm_i_deprecated_memory_return
= 0;
562 long int scm_i_last_marked_cell_count
;
564 /* Must be called while holding scm_i_sweep_mutex.
566 This function is fairly long, but it touches various global
567 variables. To not obscure the side effects on global variables,
568 this function has not been split up.
571 scm_i_gc (const char *what
)
573 unsigned long t_before_gc
= 0;
575 scm_i_thread_put_to_sleep ();
577 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
580 fprintf (stderr
,"gc reason %s\n", what
);
582 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
584 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
587 t_before_gc
= scm_c_get_internal_run_time ();
588 scm_gc_malloc_collected
= 0;
591 Set freelists to NULL so scm_cons () always triggers gc, causing
592 the assertion above to fail.
594 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
595 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
598 Let's finish the sweep. The conservative GC might point into the
599 garbage, and marking that would create a mess.
601 scm_i_sweep_all_segments ("GC", &scm_i_gc_sweep_stats
);
602 scm_check_deprecated_memory_return ();
604 #if (SCM_DEBUG_CELL_ACCESSES == 0 && SCM_SIZEOF_UNSIGNED_LONG == 4)
605 /* Sanity check our numbers. */
606 /* TODO(hanwen): figure out why the stats are off on x64_64. */
607 /* If this was not true, someone touched mark bits outside of the
609 if (scm_i_last_marked_cell_count
!= scm_i_marked_count ())
612 "The number of marked objects changed since the last GC: %d vs %d.";
613 /* At some point, we should probably use a deprecation warning. */
614 fprintf(stderr
, msg
, scm_i_last_marked_cell_count
, scm_i_marked_count ());
616 assert (scm_i_gc_sweep_stats
.swept
617 == (scm_i_master_freelist
.heap_total_cells
618 + scm_i_master_freelist2
.heap_total_cells
));
619 assert (scm_i_gc_sweep_stats
.collected
+ scm_i_last_marked_cell_count
620 == scm_i_gc_sweep_stats
.swept
);
621 #endif /* SCM_DEBUG_CELL_ACCESSES */
624 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
627 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
629 scm_i_last_marked_cell_count
= scm_cells_allocated
= scm_i_marked_count ();
633 TODO: the after_sweep hook should probably be moved to just before
634 the mark, since that's where the sweep is finished in lazy
637 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
638 original meaning implied at least two things: that it would be
641 1. the freelist is re-initialized (no evaluation possible, though)
645 2. the heap is "fresh"
646 (it is well-defined what data is used and what is not)
648 Neither of these conditions would hold just before the mark phase.
650 Of course, the lazy sweeping has muddled the distinction between
651 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
652 there were no difference, it would still be useful to have two
653 distinct classes of hook functions since this can prevent some
654 bad interference when several modules adds gc hooks.
656 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
659 Nothing here: lazy sweeping.
661 scm_i_reset_segments ();
663 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
664 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
666 /* Invalidate the freelists of other threads. */
667 scm_i_thread_invalidate_freelists ();
669 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
673 scm_i_gc_sweep_stats
.collected
= scm_i_gc_sweep_stats
.swept
= 0;
674 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
675 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
677 /* Arguably, this statistic is fairly useless: marking will dominate
680 scm_gc_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
682 scm_i_thread_wake_up ();
684 For debugging purposes, you could do
685 scm_i_sweep_all_segments ("debug"), but then the remains of the
686 cell aren't left to analyse.
692 /* {GC Protection Helper Functions}
697 * If within a function you need to protect one or more scheme objects from
698 * garbage collection, pass them as parameters to one of the
699 * scm_remember_upto_here* functions below. These functions don't do
700 * anything, but since the compiler does not know that they are actually
701 * no-ops, it will generate code that calls these functions with the given
702 * parameters. Therefore, you can be sure that the compiler will keep those
703 * scheme values alive (on the stack or in a register) up to the point where
704 * scm_remember_upto_here* is called. In other words, place the call to
705 * scm_remember_upto_here* _behind_ the last code in your function, that
706 * depends on the scheme object to exist.
708 * Example: We want to make sure that the string object str does not get
709 * garbage collected during the execution of 'some_function' in the code
710 * below, because otherwise the characters belonging to str would be freed and
711 * 'some_function' might access freed memory. To make sure that the compiler
712 * keeps str alive on the stack or in a register such that it is visible to
713 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
714 * call to 'some_function'. Note that this would not be necessary if str was
715 * used anyway after the call to 'some_function'.
716 * char *chars = scm_i_string_chars (str);
717 * some_function (chars);
718 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
721 /* Remove any macro versions of these while defining the functions.
722 Functions are always included in the library, for upward binary
723 compatibility and in case combinations of GCC and non-GCC are used. */
724 #undef scm_remember_upto_here_1
725 #undef scm_remember_upto_here_2
728 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
730 /* Empty. Protects a single object from garbage collection. */
734 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
736 /* Empty. Protects two objects from garbage collection. */
740 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
742 /* Empty. Protects any number of objects from garbage collection. */
746 These crazy functions prevent garbage collection
747 of arguments after the first argument by
748 ensuring they remain live throughout the
749 function because they are used in the last
750 line of the code block.
751 It'd be better to have a nice compiler hint to
752 aid the conservative stack-scanning GC. --03/09/00 gjb */
754 scm_return_first (SCM elt
, ...)
760 scm_return_first_int (int i
, ...)
767 scm_permanent_object (SCM obj
)
769 SCM cell
= scm_cons (obj
, SCM_EOL
);
770 SCM_CRITICAL_SECTION_START
;
771 SCM_SETCDR (cell
, scm_permobjs
);
773 SCM_CRITICAL_SECTION_END
;
778 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
779 other references are dropped, until the object is unprotected by calling
780 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
781 i. e. it is possible to protect the same object several times, but it is
782 necessary to unprotect the object the same number of times to actually get
783 the object unprotected. It is an error to unprotect an object more often
784 than it has been protected before. The function scm_protect_object returns
788 /* Implementation note: For every object X, there is a counter which
789 scm_gc_protect_object (X) increments and scm_gc_unprotect_object (X) decrements.
795 scm_gc_protect_object (SCM obj
)
799 /* This critical section barrier will be replaced by a mutex. */
800 /* njrev: Indeed; if my comment above is correct, there is the same
801 critsec/mutex inconsistency here. */
802 SCM_CRITICAL_SECTION_START
;
804 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
805 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
807 protected_obj_count
++;
809 SCM_CRITICAL_SECTION_END
;
815 /* Remove any protection for OBJ established by a prior call to
816 scm_protect_object. This function returns OBJ.
818 See scm_protect_object for more information. */
820 scm_gc_unprotect_object (SCM obj
)
824 /* This critical section barrier will be replaced by a mutex. */
825 /* njrev: and again. */
826 SCM_CRITICAL_SECTION_START
;
828 if (scm_gc_running_p
)
830 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
834 handle
= scm_hashq_get_handle (scm_protects
, obj
);
836 if (scm_is_false (handle
))
838 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
843 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
844 if (scm_is_eq (count
, scm_from_int (0)))
845 scm_hashq_remove_x (scm_protects
, obj
);
847 SCM_SETCDR (handle
, count
);
849 protected_obj_count
--;
851 SCM_CRITICAL_SECTION_END
;
857 scm_gc_register_root (SCM
*p
)
860 SCM key
= scm_from_ulong ((unsigned long) p
);
862 /* This critical section barrier will be replaced by a mutex. */
863 /* njrev: and again. */
864 SCM_CRITICAL_SECTION_START
;
866 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
868 /* njrev: note also that the above can probably signal an error */
869 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
871 SCM_CRITICAL_SECTION_END
;
875 scm_gc_unregister_root (SCM
*p
)
878 SCM key
= scm_from_ulong ((unsigned long) p
);
880 /* This critical section barrier will be replaced by a mutex. */
881 /* njrev: and again. */
882 SCM_CRITICAL_SECTION_START
;
884 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
886 if (scm_is_false (handle
))
888 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
893 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
894 if (scm_is_eq (count
, scm_from_int (0)))
895 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
897 SCM_SETCDR (handle
, count
);
900 SCM_CRITICAL_SECTION_END
;
904 scm_gc_register_roots (SCM
*b
, unsigned long n
)
907 for (; p
< b
+ n
; ++p
)
908 scm_gc_register_root (p
);
912 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
915 for (; p
< b
+ n
; ++p
)
916 scm_gc_unregister_root (p
);
919 int scm_i_terminating
;
925 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
928 /* Get an integer from an environment variable. */
930 scm_getenv_int (const char *var
, int def
)
933 char *val
= getenv (var
);
937 res
= strtol (val
, &end
, 10);
944 scm_storage_prehistory ()
946 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
947 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
948 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
949 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
950 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
953 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
960 j
= SCM_NUM_PROTECTS
;
962 scm_sys_protects
[--j
] = SCM_BOOL_F
;
964 scm_gc_init_freelist ();
965 scm_gc_init_malloc ();
968 /* We can't have a cleanup handler since we have no thread to run it
975 on_exit (cleanup
, 0);
981 scm_stand_in_procs
= scm_make_weak_key_hash_table (scm_from_int (257));
982 scm_permobjs
= SCM_EOL
;
983 scm_protects
= scm_c_make_hash_table (31);
984 scm_gc_registered_roots
= scm_c_make_hash_table (31);
991 SCM scm_after_gc_hook
;
995 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
996 * is run after the gc, as soon as the asynchronous events are handled by the
1000 gc_async_thunk (void)
1002 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
1003 return SCM_UNSPECIFIED
;
1007 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
1008 * the garbage collection. The only purpose of this function is to mark the
1009 * gc_async (which will eventually lead to the execution of the
1013 mark_gc_async (void * hook_data SCM_UNUSED
,
1014 void *fn_data SCM_UNUSED
,
1015 void *data SCM_UNUSED
)
1017 /* If cell access debugging is enabled, the user may choose to perform
1018 * additional garbage collections after an arbitrary number of cell
1019 * accesses. We don't want the scheme level after-gc-hook to be performed
1020 * for each of these garbage collections for the following reason: The
1021 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
1022 * after-gc-hook was performed with every gc, and if the gc was performed
1023 * after a very small number of cell accesses, then the number of cell
1024 * accesses during the execution of the after-gc-hook will suffice to cause
1025 * the execution of the next gc. Then, guile would keep executing the
1026 * after-gc-hook over and over again, and would never come to do other
1029 * To overcome this problem, if cell access debugging with additional
1030 * garbage collections is enabled, the after-gc-hook is never run by the
1031 * garbage collecter. When running guile with cell access debugging and the
1032 * execution of the after-gc-hook is desired, then it is necessary to run
1033 * the hook explicitly from the user code. This has the effect, that from
1034 * the scheme level point of view it seems that garbage collection is
1035 * performed with a much lower frequency than it actually is. Obviously,
1036 * this will not work for code that depends on a fixed one to one
1037 * relationship between the execution counts of the C level garbage
1038 * collection hooks and the execution count of the scheme level
1042 #if (SCM_DEBUG_CELL_ACCESSES == 1)
1043 if (scm_debug_cells_gc_interval
== 0)
1044 scm_system_async_mark (gc_async
);
1046 scm_system_async_mark (gc_async
);
1055 scm_gc_init_mark ();
1057 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
1058 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
1060 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
1063 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
1065 #include "libguile/gc.x"
1070 # include <sys/param.h>
1071 # include <sys/pstat.h>
1073 scm_ia64_register_backing_store_base (void)
1075 struct pst_vm_status vm_status
;
1077 while (pstat_getprocvm (&vm_status
, sizeof (vm_status
), 0, i
++) == 1)
1078 if (vm_status
.pst_type
== PS_RSESTACK
)
1079 return (void *) vm_status
.pst_vaddr
;
1083 scm_ia64_ar_bsp (const void *ctx
)
1086 __uc_get_ar_bsp (ctx
, &bsp
);
1087 return (void *) bsp
;
1091 # include <ucontext.h>
1093 scm_ia64_register_backing_store_base (void)
1095 extern void *__libc_ia64_register_backing_store_base
;
1096 return __libc_ia64_register_backing_store_base
;
1099 scm_ia64_ar_bsp (const void *opaque
)
1101 const ucontext_t
*ctx
= opaque
;
1102 return (void *) ctx
->uc_mcontext
.sc_ar_bsp
;
1105 #endif /* __ia64__ */
1109 #define FUNC_NAME "scm_gc_sweep"