1 /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 2006, 2008 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
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
8 * This library is distributed in the hope that it will be useful,
9 * but 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 02110-1301 USA
20 /* #define DEBUGINFO */
31 #include "libguile/_scm.h"
32 #include "libguile/eval.h"
33 #include "libguile/stime.h"
34 #include "libguile/stackchk.h"
35 #include "libguile/struct.h"
36 #include "libguile/smob.h"
37 #include "libguile/unif.h"
38 #include "libguile/async.h"
39 #include "libguile/ports.h"
40 #include "libguile/root.h"
41 #include "libguile/strings.h"
42 #include "libguile/vectors.h"
43 #include "libguile/weaks.h"
44 #include "libguile/hashtab.h"
45 #include "libguile/tags.h"
47 #include "libguile/private-gc.h"
48 #include "libguile/validate.h"
49 #include "libguile/deprecation.h"
50 #include "libguile/gc.h"
51 #include "libguile/dynwind.h"
53 #ifdef GUILE_DEBUG_MALLOC
54 #include "libguile/debug-malloc.h"
65 /* Lock this mutex before doing lazy sweeping.
67 scm_i_pthread_mutex_t scm_i_sweep_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
69 /* Set this to != 0 if every cell that is accessed shall be checked:
71 int scm_debug_cell_accesses_p
= 0;
72 int scm_expensive_debug_cell_accesses_p
= 0;
74 /* Set this to 0 if no additional gc's shall be performed, otherwise set it to
75 * the number of cell accesses after which a gc shall be called.
77 int scm_debug_cells_gc_interval
= 0;
80 Global variable, so you can switch it off at runtime by setting
81 scm_i_cell_validation_already_running.
83 int scm_i_cell_validation_already_running
;
85 #if (SCM_DEBUG_CELL_ACCESSES == 1)
90 Assert that the given object is a valid reference to a valid cell. This
91 test involves to determine whether the object is a cell pointer, whether
92 this pointer actually points into a heap segment and whether the cell
93 pointed to is not a free cell. Further, additional garbage collections may
94 get executed after a user defined number of cell accesses. This helps to
95 find places in the C code where references are dropped for extremely short
100 scm_i_expensive_validation_check (SCM cell
)
102 if (!scm_in_heap_p (cell
))
104 fprintf (stderr
, "scm_assert_cell_valid: this object does not live in the heap: %lux\n",
105 (unsigned long) SCM_UNPACK (cell
));
109 /* If desired, perform additional garbage collections after a user
110 * defined number of cell accesses.
112 if (scm_debug_cells_gc_interval
)
114 static unsigned int counter
= 0;
122 counter
= scm_debug_cells_gc_interval
;
129 scm_assert_cell_valid (SCM cell
)
131 if (!scm_i_cell_validation_already_running
&& scm_debug_cell_accesses_p
)
133 scm_i_cell_validation_already_running
= 1; /* set to avoid recursion */
136 During GC, no user-code should be run, and the guile core
137 should use non-protected accessors.
139 if (scm_gc_running_p
)
143 Only scm_in_heap_p and rescanning the heap is wildly
146 if (scm_expensive_debug_cell_accesses_p
)
147 scm_i_expensive_validation_check (cell
);
149 if (!SCM_GC_MARK_P (cell
))
152 "scm_assert_cell_valid: this object is unmarked. \n"
153 "It has been garbage-collected in the last GC run: "
155 (unsigned long) SCM_UNPACK (cell
));
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;
214 /* Global GC sweep statistics since the last full GC. */
215 static scm_t_sweep_statistics scm_i_gc_sweep_stats
= { 0, 0 };
216 static scm_t_sweep_statistics scm_i_gc_sweep_stats_1
= { 0, 0 };
218 /* Total count of cells marked/swept. */
219 static double scm_gc_cells_marked_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 t_before_gc
;
225 static unsigned long scm_gc_mark_time_taken
= 0;
227 static unsigned long scm_gc_times
= 0;
229 static int scm_gc_cell_yield_percentage
= 0;
230 static unsigned long protected_obj_count
= 0;
232 /* The following are accessed from `gc-malloc.c' and `gc-card.c'. */
233 int scm_gc_malloc_yield_percentage
= 0;
234 unsigned long scm_gc_malloc_collected
= 0;
237 SCM_SYMBOL (sym_cells_allocated
, "cells-allocated");
238 SCM_SYMBOL (sym_heap_size
, "cell-heap-size");
239 SCM_SYMBOL (sym_mallocated
, "bytes-malloced");
240 SCM_SYMBOL (sym_mtrigger
, "gc-malloc-threshold");
241 SCM_SYMBOL (sym_heap_segments
, "cell-heap-segments");
242 SCM_SYMBOL (sym_gc_time_taken
, "gc-time-taken");
243 SCM_SYMBOL (sym_gc_mark_time_taken
, "gc-mark-time-taken");
244 SCM_SYMBOL (sym_times
, "gc-times");
245 SCM_SYMBOL (sym_cells_marked
, "cells-marked");
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_min_cell_yield
, "min-cell-yield");
250 SCM_SYMBOL (sym_min_double_cell_yield
, "min-double-cell-yield");
251 SCM_SYMBOL (sym_protected_objects
, "protected-objects");
252 SCM_SYMBOL (sym_total_cells_allocated
, "total-cells-allocated");
255 /* Number of calls to SCM_NEWCELL since startup. */
256 unsigned scm_newcell_count
;
257 unsigned scm_newcell2_count
;
260 /* {Scheme Interface to GC}
263 tag_table_to_type_alist (void *closure
, SCM key
, SCM val
, SCM acc
)
265 if (scm_is_integer (key
))
267 int c_tag
= scm_to_int (key
);
269 char const * name
= scm_i_tag_name (c_tag
);
272 key
= scm_from_locale_string (name
);
277 sprintf (s
, "tag %d", c_tag
);
278 key
= scm_from_locale_string (s
);
282 return scm_cons (scm_cons (key
, val
), acc
);
285 SCM_DEFINE (scm_gc_live_object_stats
, "gc-live-object-stats", 0, 0, 0,
287 "Return an alist of statistics of the current live objects. ")
288 #define FUNC_NAME s_scm_gc_live_object_stats
290 SCM tab
= scm_make_hash_table (scm_from_int (57));
293 scm_i_all_segments_statistics (tab
);
296 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
302 extern int scm_gc_malloc_yield_percentage
;
303 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
305 "Return an association list of statistics about Guile's current\n"
307 #define FUNC_NAME s_scm_gc_stats
310 SCM heap_segs
= SCM_EOL
;
311 unsigned long int local_scm_mtrigger
;
312 unsigned long int local_scm_mallocated
;
313 unsigned long int local_scm_heap_size
;
314 int local_scm_gc_cell_yield_percentage
;
315 int local_scm_gc_malloc_yield_percentage
;
316 unsigned long int local_scm_cells_allocated
;
317 unsigned long int local_scm_gc_time_taken
;
318 unsigned long int local_scm_gc_times
;
319 unsigned long int local_scm_gc_mark_time_taken
;
320 unsigned long int local_protected_obj_count
;
321 unsigned long int local_min_cell_yield
;
322 unsigned long int local_min_double_cell_yield
;
323 double local_scm_gc_cells_swept
;
324 double local_scm_gc_cells_marked
;
325 double local_scm_total_cells_allocated
;
327 unsigned long *bounds
= 0;
328 int table_size
= scm_i_heap_segment_table_size
;
329 SCM_CRITICAL_SECTION_START
;
332 temporarily store the numbers, so as not to cause GC.
334 bounds
= malloc (sizeof (unsigned long) * table_size
* 2);
337 for (i
= table_size
; i
--; )
339 bounds
[2*i
] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[0];
340 bounds
[2*i
+1] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[1];
344 /* Below, we cons to produce the resulting list. We want a snapshot of
345 * the heap situation before consing.
347 local_scm_mtrigger
= scm_mtrigger
;
348 local_scm_mallocated
= scm_mallocated
;
349 local_scm_heap_size
= SCM_HEAP_SIZE
;
351 local_scm_cells_allocated
= scm_cells_allocated
;
352 local_min_cell_yield
= scm_i_master_freelist
.min_yield
;
353 local_min_double_cell_yield
= scm_i_master_freelist2
.min_yield
;
355 local_scm_gc_time_taken
= scm_gc_time_taken
;
356 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
357 local_scm_gc_times
= scm_gc_times
;
358 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
359 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
360 local_protected_obj_count
= protected_obj_count
;
361 local_scm_gc_cells_swept
=
362 (double) scm_gc_cells_swept_acc
363 + (double) scm_i_gc_sweep_stats
.swept
;
364 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
365 +(double) scm_i_gc_sweep_stats
.swept
366 -(double) scm_i_gc_sweep_stats
.collected
;
368 local_scm_total_cells_allocated
= scm_gc_cells_allocated_acc
369 + (double) (scm_cells_allocated
- scm_last_cells_allocated
);
371 for (i
= table_size
; i
--;)
373 heap_segs
= scm_cons (scm_cons (scm_from_ulong (bounds
[2*i
]),
374 scm_from_ulong (bounds
[2*i
+1])),
377 /* njrev: can any of these scm_cons's or scm_list_n signal a memory
378 error? If so we need a frame here. */
380 scm_list_n (scm_cons (sym_gc_time_taken
,
381 scm_from_ulong (local_scm_gc_time_taken
)),
382 scm_cons (sym_cells_allocated
,
383 scm_from_ulong (local_scm_cells_allocated
)),
384 scm_cons (sym_total_cells_allocated
,
385 scm_from_double (local_scm_total_cells_allocated
)),
386 scm_cons (sym_heap_size
,
387 scm_from_ulong (local_scm_heap_size
)),
388 scm_cons (sym_mallocated
,
389 scm_from_ulong (local_scm_mallocated
)),
390 scm_cons (sym_mtrigger
,
391 scm_from_ulong (local_scm_mtrigger
)),
393 scm_from_ulong (local_scm_gc_times
)),
394 scm_cons (sym_gc_mark_time_taken
,
395 scm_from_ulong (local_scm_gc_mark_time_taken
)),
396 scm_cons (sym_cells_marked
,
397 scm_from_double (local_scm_gc_cells_marked
)),
398 scm_cons (sym_cells_swept
,
399 scm_from_double (local_scm_gc_cells_swept
)),
400 scm_cons (sym_malloc_yield
,
401 scm_from_long(local_scm_gc_malloc_yield_percentage
)),
402 scm_cons (sym_cell_yield
,
403 scm_from_long (local_scm_gc_cell_yield_percentage
)),
404 scm_cons (sym_protected_objects
,
405 scm_from_ulong (local_protected_obj_count
)),
406 scm_cons (sym_min_cell_yield
,
407 scm_from_ulong (local_min_cell_yield
)),
408 scm_cons (sym_min_double_cell_yield
,
409 scm_from_ulong (local_min_double_cell_yield
)),
410 scm_cons (sym_heap_segments
, heap_segs
),
412 SCM_CRITICAL_SECTION_END
;
419 /* Update the global sweeping/collection statistics by adding SWEEP_STATS to
420 SCM_I_GC_SWEEP_STATS and updating related variables. */
422 gc_update_stats (scm_t_sweep_statistics sweep_stats
)
424 /* CELLS SWEPT is another word for the number of cells that were examined
425 during GC. YIELD is the number that we cleaned out. MARKED is the number
426 that weren't cleaned. */
428 scm_gc_cell_yield_percentage
= (sweep_stats
.collected
* 100) / SCM_HEAP_SIZE
;
430 scm_i_sweep_statistics_sum (&scm_i_gc_sweep_stats
, sweep_stats
);
432 if ((scm_i_gc_sweep_stats
.collected
> scm_i_gc_sweep_stats
.swept
)
433 || (scm_cells_allocated
< sweep_stats
.collected
))
435 printf ("internal GC error, please report to `"
436 PACKAGE_BUGREPORT
"'\n");
440 scm_gc_cells_allocated_acc
+=
441 (double) (scm_cells_allocated
- scm_last_cells_allocated
);
443 scm_cells_allocated
-= sweep_stats
.collected
;
444 scm_last_cells_allocated
= scm_cells_allocated
;
448 gc_start_stats (const char *what SCM_UNUSED
)
450 t_before_gc
= scm_c_get_internal_run_time ();
452 scm_gc_malloc_collected
= 0;
456 gc_end_stats (scm_t_sweep_statistics sweep_stats
)
458 unsigned long t
= scm_c_get_internal_run_time ();
460 scm_gc_time_taken
+= (t
- t_before_gc
);
462 /* Reset the number of cells swept/collected since the last full GC. */
463 scm_i_gc_sweep_stats_1
= scm_i_gc_sweep_stats
;
464 scm_i_gc_sweep_stats
.collected
= scm_i_gc_sweep_stats
.swept
= 0;
466 gc_update_stats (sweep_stats
);
468 scm_gc_cells_marked_acc
+= (double) scm_i_gc_sweep_stats
.swept
469 - (double) scm_i_gc_sweep_stats
.collected
;
470 scm_gc_cells_swept_acc
+= (double) scm_i_gc_sweep_stats
.swept
;
476 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
478 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
479 "returned by this function for @var{obj}")
480 #define FUNC_NAME s_scm_object_address
482 return scm_from_ulong (SCM_UNPACK (obj
));
487 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
489 "Scans all of SCM objects and reclaims for further use those that are\n"
490 "no longer accessible.")
491 #define FUNC_NAME s_scm_gc
493 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
494 scm_gc_running_p
= 1;
496 /* njrev: It looks as though other places, e.g. scm_realloc,
497 can call scm_i_gc without acquiring the sweep mutex. Does this
498 matter? Also scm_i_gc (or its descendants) touch the
499 scm_sys_protects, which are protected in some cases
500 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
501 not by the sweep mutex. Shouldn't all the GC-relevant objects be
502 protected in the same way? */
503 scm_gc_running_p
= 0;
504 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
505 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
506 return SCM_UNSPECIFIED
;
513 /* The master is global and common while the freelist will be
514 * individual for each thread.
518 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
522 scm_t_sweep_statistics sweep_stats
;
524 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
525 scm_gc_running_p
= 1;
527 *free_cells
= scm_i_sweep_some_segments (freelist
, &sweep_stats
);
528 gc_update_stats (sweep_stats
);
530 if (*free_cells
== SCM_EOL
&& scm_i_gc_grow_heap_p (freelist
))
532 freelist
->heap_segment_idx
=
533 scm_i_get_new_heap_segment (freelist
,
534 scm_i_gc_sweep_stats
,
537 *free_cells
= scm_i_sweep_some_segments (freelist
, &sweep_stats
);
538 gc_update_stats (sweep_stats
);
541 if (*free_cells
== SCM_EOL
)
544 with the advent of lazy sweep, GC yield is only known just
547 scm_i_adjust_min_yield (freelist
,
548 scm_i_gc_sweep_stats
,
549 scm_i_gc_sweep_stats_1
);
552 out of fresh cells. Try to get some new ones.
557 *free_cells
= scm_i_sweep_some_segments (freelist
, &sweep_stats
);
558 gc_update_stats (sweep_stats
);
561 if (*free_cells
== SCM_EOL
)
564 failed getting new cells. Get new juice or die.
566 freelist
->heap_segment_idx
=
567 scm_i_get_new_heap_segment (freelist
,
568 scm_i_gc_sweep_stats
,
571 *free_cells
= scm_i_sweep_some_segments (freelist
, &sweep_stats
);
572 gc_update_stats (sweep_stats
);
575 if (*free_cells
== SCM_EOL
)
580 *free_cells
= SCM_FREE_CELL_CDR (cell
);
582 scm_gc_running_p
= 0;
583 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
586 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
592 scm_t_c_hook scm_before_gc_c_hook
;
593 scm_t_c_hook scm_before_mark_c_hook
;
594 scm_t_c_hook scm_before_sweep_c_hook
;
595 scm_t_c_hook scm_after_sweep_c_hook
;
596 scm_t_c_hook scm_after_gc_c_hook
;
598 /* Must be called while holding scm_i_sweep_mutex.
602 scm_i_gc (const char *what
)
604 scm_t_sweep_statistics sweep_stats
;
606 scm_i_thread_put_to_sleep ();
608 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
611 fprintf (stderr
,"gc reason %s\n", what
);
614 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
616 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
619 gc_start_stats (what
);
622 Set freelists to NULL so scm_cons() always triggers gc, causing
623 the assertion above to fail.
625 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
626 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
629 Let's finish the sweep. The conservative GC might point into the
630 garbage, and marking that would create a mess.
632 scm_i_sweep_all_segments ("GC", &sweep_stats
);
634 /* Invariant: the number of cells collected (i.e., freed) must always be
635 lower than or equal to the number of cells "swept" (i.e., visited). */
636 assert (sweep_stats
.collected
<= sweep_stats
.swept
);
638 if (scm_mallocated
< scm_i_deprecated_memory_return
)
640 /* The byte count of allocated objects has underflowed. This is
641 probably because you forgot to report the sizes of objects you
642 have allocated, by calling scm_done_malloc or some such. When
643 the GC freed them, it subtracted their size from
644 scm_mallocated, which underflowed. */
646 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
647 "This is probably because the GC hasn't been correctly informed\n"
648 "about object sizes\n");
651 scm_mallocated
-= scm_i_deprecated_memory_return
;
656 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
658 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
662 TODO: the after_sweep hook should probably be moved to just before
663 the mark, since that's where the sweep is finished in lazy
666 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
667 original meaning implied at least two things: that it would be
670 1. the freelist is re-initialized (no evaluation possible, though)
674 2. the heap is "fresh"
675 (it is well-defined what data is used and what is not)
677 Neither of these conditions would hold just before the mark phase.
679 Of course, the lazy sweeping has muddled the distinction between
680 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
681 there were no difference, it would still be useful to have two
682 distinct classes of hook functions since this can prevent some
683 bad interference when several modules adds gc hooks.
686 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
688 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
690 gc_end_stats (sweep_stats
);
692 scm_i_thread_wake_up ();
695 For debugging purposes, you could do
696 scm_i_sweep_all_segments("debug"), but then the remains of the
697 cell aren't left to analyse.
703 /* {GC Protection Helper Functions}
708 * If within a function you need to protect one or more scheme objects from
709 * garbage collection, pass them as parameters to one of the
710 * scm_remember_upto_here* functions below. These functions don't do
711 * anything, but since the compiler does not know that they are actually
712 * no-ops, it will generate code that calls these functions with the given
713 * parameters. Therefore, you can be sure that the compiler will keep those
714 * scheme values alive (on the stack or in a register) up to the point where
715 * scm_remember_upto_here* is called. In other words, place the call to
716 * scm_remember_upto_here* _behind_ the last code in your function, that
717 * depends on the scheme object to exist.
719 * Example: We want to make sure that the string object str does not get
720 * garbage collected during the execution of 'some_function' in the code
721 * below, because otherwise the characters belonging to str would be freed and
722 * 'some_function' might access freed memory. To make sure that the compiler
723 * keeps str alive on the stack or in a register such that it is visible to
724 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
725 * call to 'some_function'. Note that this would not be necessary if str was
726 * used anyway after the call to 'some_function'.
727 * char *chars = scm_i_string_chars (str);
728 * some_function (chars);
729 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
732 /* Remove any macro versions of these while defining the functions.
733 Functions are always included in the library, for upward binary
734 compatibility and in case combinations of GCC and non-GCC are used. */
735 #undef scm_remember_upto_here_1
736 #undef scm_remember_upto_here_2
739 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
741 /* Empty. Protects a single object from garbage collection. */
745 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
747 /* Empty. Protects two objects from garbage collection. */
751 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
753 /* Empty. Protects any number of objects from garbage collection. */
757 These crazy functions prevent garbage collection
758 of arguments after the first argument by
759 ensuring they remain live throughout the
760 function because they are used in the last
761 line of the code block.
762 It'd be better to have a nice compiler hint to
763 aid the conservative stack-scanning GC. --03/09/00 gjb */
765 scm_return_first (SCM elt
, ...)
771 scm_return_first_int (int i
, ...)
778 scm_permanent_object (SCM obj
)
780 SCM cell
= scm_cons (obj
, SCM_EOL
);
781 SCM_CRITICAL_SECTION_START
;
782 SCM_SETCDR (cell
, scm_permobjs
);
784 SCM_CRITICAL_SECTION_END
;
789 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
790 other references are dropped, until the object is unprotected by calling
791 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
792 i. e. it is possible to protect the same object several times, but it is
793 necessary to unprotect the object the same number of times to actually get
794 the object unprotected. It is an error to unprotect an object more often
795 than it has been protected before. The function scm_protect_object returns
799 /* Implementation note: For every object X, there is a counter which
800 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
806 scm_gc_protect_object (SCM obj
)
810 /* This critical section barrier will be replaced by a mutex. */
811 /* njrev: Indeed; if my comment above is correct, there is the same
812 critsec/mutex inconsistency here. */
813 SCM_CRITICAL_SECTION_START
;
815 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
816 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
818 protected_obj_count
++;
820 SCM_CRITICAL_SECTION_END
;
826 /* Remove any protection for OBJ established by a prior call to
827 scm_protect_object. This function returns OBJ.
829 See scm_protect_object for more information. */
831 scm_gc_unprotect_object (SCM obj
)
835 /* This critical section barrier will be replaced by a mutex. */
836 /* njrev: and again. */
837 SCM_CRITICAL_SECTION_START
;
839 if (scm_gc_running_p
)
841 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
845 handle
= scm_hashq_get_handle (scm_protects
, obj
);
847 if (scm_is_false (handle
))
849 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
854 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
855 if (scm_is_eq (count
, scm_from_int (0)))
856 scm_hashq_remove_x (scm_protects
, obj
);
858 SCM_SETCDR (handle
, count
);
860 protected_obj_count
--;
862 SCM_CRITICAL_SECTION_END
;
868 scm_gc_register_root (SCM
*p
)
871 SCM key
= scm_from_ulong ((unsigned long) p
);
873 /* This critical section barrier will be replaced by a mutex. */
874 /* njrev: and again. */
875 SCM_CRITICAL_SECTION_START
;
877 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
879 /* njrev: note also that the above can probably signal an error */
880 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
882 SCM_CRITICAL_SECTION_END
;
886 scm_gc_unregister_root (SCM
*p
)
889 SCM key
= scm_from_ulong ((unsigned long) p
);
891 /* This critical section barrier will be replaced by a mutex. */
892 /* njrev: and again. */
893 SCM_CRITICAL_SECTION_START
;
895 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
897 if (scm_is_false (handle
))
899 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
904 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
905 if (scm_is_eq (count
, scm_from_int (0)))
906 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
908 SCM_SETCDR (handle
, count
);
911 SCM_CRITICAL_SECTION_END
;
915 scm_gc_register_roots (SCM
*b
, unsigned long n
)
918 for (; p
< b
+ n
; ++p
)
919 scm_gc_register_root (p
);
923 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
926 for (; p
< b
+ n
; ++p
)
927 scm_gc_unregister_root (p
);
930 int scm_i_terminating
;
936 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
939 /* Get an integer from an environment variable. */
941 scm_getenv_int (const char *var
, int def
)
944 char *val
= getenv (var
);
948 res
= strtol (val
, &end
, 10);
955 scm_storage_prehistory ()
957 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
958 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
959 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
960 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
961 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
964 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
971 j
= SCM_NUM_PROTECTS
;
973 scm_sys_protects
[--j
] = SCM_BOOL_F
;
975 scm_gc_init_freelist();
976 scm_gc_init_malloc ();
978 j
= SCM_HEAP_SEG_SIZE
;
981 /* We can't have a cleanup handler since we have no thread to run it
988 on_exit (cleanup
, 0);
994 scm_stand_in_procs
= scm_make_weak_key_hash_table (scm_from_int (257));
995 scm_permobjs
= SCM_EOL
;
996 scm_protects
= scm_c_make_hash_table (31);
997 scm_gc_registered_roots
= scm_c_make_hash_table (31);
1004 SCM scm_after_gc_hook
;
1006 static SCM gc_async
;
1008 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
1009 * is run after the gc, as soon as the asynchronous events are handled by the
1013 gc_async_thunk (void)
1015 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
1016 return SCM_UNSPECIFIED
;
1020 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
1021 * the garbage collection. The only purpose of this function is to mark the
1022 * gc_async (which will eventually lead to the execution of the
1026 mark_gc_async (void * hook_data SCM_UNUSED
,
1027 void *fn_data SCM_UNUSED
,
1028 void *data SCM_UNUSED
)
1030 /* If cell access debugging is enabled, the user may choose to perform
1031 * additional garbage collections after an arbitrary number of cell
1032 * accesses. We don't want the scheme level after-gc-hook to be performed
1033 * for each of these garbage collections for the following reason: The
1034 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
1035 * after-gc-hook was performed with every gc, and if the gc was performed
1036 * after a very small number of cell accesses, then the number of cell
1037 * accesses during the execution of the after-gc-hook will suffice to cause
1038 * the execution of the next gc. Then, guile would keep executing the
1039 * after-gc-hook over and over again, and would never come to do other
1042 * To overcome this problem, if cell access debugging with additional
1043 * garbage collections is enabled, the after-gc-hook is never run by the
1044 * garbage collecter. When running guile with cell access debugging and the
1045 * execution of the after-gc-hook is desired, then it is necessary to run
1046 * the hook explicitly from the user code. This has the effect, that from
1047 * the scheme level point of view it seems that garbage collection is
1048 * performed with a much lower frequency than it actually is. Obviously,
1049 * this will not work for code that depends on a fixed one to one
1050 * relationship between the execution counts of the C level garbage
1051 * collection hooks and the execution count of the scheme level
1055 #if (SCM_DEBUG_CELL_ACCESSES == 1)
1056 if (scm_debug_cells_gc_interval
== 0)
1057 scm_system_async_mark (gc_async
);
1059 scm_system_async_mark (gc_async
);
1068 scm_gc_init_mark ();
1070 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
1071 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
1073 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
1076 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
1078 #include "libguile/gc.x"
1083 # include <sys/param.h>
1084 # include <sys/pstat.h>
1086 scm_ia64_register_backing_store_base (void)
1088 struct pst_vm_status vm_status
;
1090 while (pstat_getprocvm (&vm_status
, sizeof (vm_status
), 0, i
++) == 1)
1091 if (vm_status
.pst_type
== PS_RSESTACK
)
1092 return (void *) vm_status
.pst_vaddr
;
1096 scm_ia64_ar_bsp (const void *ctx
)
1099 __uc_get_ar_bsp(ctx
, &bsp
);
1100 return (void *) bsp
;
1104 # include <ucontext.h>
1106 scm_ia64_register_backing_store_base (void)
1108 extern void *__libc_ia64_register_backing_store_base
;
1109 return __libc_ia64_register_backing_store_base
;
1112 scm_ia64_ar_bsp (const void *opaque
)
1114 const ucontext_t
*ctx
= opaque
;
1115 return (void *) ctx
->uc_mcontext
.sc_ar_bsp
;
1118 #endif /* __ia64__ */
1122 #define FUNC_NAME "scm_gc_sweep"
1124 scm_i_deprecated_memory_return
= 0;
1126 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
1127 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
1130 NOTHING HERE: LAZY SWEEPING !
1132 scm_i_reset_segments ();
1134 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
1135 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
1137 /* Invalidate the freelists of other threads. */
1138 scm_i_thread_invalidate_freelists ();