Commit | Line | Data |
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71c7cfa5 | 1 | /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc. |
c7743d02 | 2 | * |
73be1d9e MV |
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. | |
c7743d02 | 7 | * |
73be1d9e | 8 | * This library is distributed in the hope that it will be useful, |
c7743d02 | 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
73be1d9e MV |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
11 | * Lesser General Public License for more details. | |
c7743d02 | 12 | * |
73be1d9e MV |
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 | |
92205699 | 15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
73be1d9e | 16 | */ |
c7743d02 HWN |
17 | |
18 | ||
19 | \f | |
3ba436c8 RB |
20 | #if HAVE_CONFIG_H |
21 | # include <config.h> | |
22 | #endif | |
23 | ||
c7743d02 HWN |
24 | #include <stdio.h> |
25 | #include <errno.h> | |
26 | #include <string.h> | |
27 | #include <assert.h> | |
28 | ||
29 | #ifdef __ia64__ | |
30 | #include <ucontext.h> | |
31 | extern unsigned long * __libc_ia64_register_backing_store_base; | |
32 | #endif | |
33 | ||
34 | #include "libguile/_scm.h" | |
35 | #include "libguile/eval.h" | |
36 | #include "libguile/stime.h" | |
37 | #include "libguile/stackchk.h" | |
38 | #include "libguile/struct.h" | |
39 | #include "libguile/smob.h" | |
40 | #include "libguile/unif.h" | |
41 | #include "libguile/async.h" | |
42 | #include "libguile/ports.h" | |
43 | #include "libguile/root.h" | |
44 | #include "libguile/strings.h" | |
45 | #include "libguile/vectors.h" | |
46 | #include "libguile/weaks.h" | |
47 | #include "libguile/hashtab.h" | |
48 | #include "libguile/tags.h" | |
49 | #include "libguile/private-gc.h" | |
50 | #include "libguile/validate.h" | |
51 | #include "libguile/deprecation.h" | |
52 | #include "libguile/gc.h" | |
06c1d900 | 53 | #include "libguile/guardians.h" |
c7743d02 HWN |
54 | |
55 | #ifdef GUILE_DEBUG_MALLOC | |
56 | #include "libguile/debug-malloc.h" | |
57 | #endif | |
58 | ||
59 | #ifdef HAVE_MALLOC_H | |
60 | #include <malloc.h> | |
61 | #endif | |
62 | ||
63 | #ifdef HAVE_UNISTD_H | |
64 | #include <unistd.h> | |
65 | #endif | |
66 | ||
c7743d02 HWN |
67 | /* |
68 | Entry point for this file. | |
69 | */ | |
70 | void | |
71 | scm_mark_all (void) | |
72 | { | |
73 | long j; | |
71c7cfa5 | 74 | int loops; |
06c1d900 | 75 | |
d09752ff | 76 | scm_i_marking = 1; |
06c1d900 MV |
77 | scm_i_init_weak_vectors_for_gc (); |
78 | scm_i_init_guardians_for_gc (); | |
c7743d02 HWN |
79 | |
80 | scm_i_clear_mark_space (); | |
40945e5e | 81 | scm_i_find_heap_calls = 0; |
c7743d02 HWN |
82 | /* Mark every thread's stack and registers */ |
83 | scm_threads_mark_stacks (); | |
84 | ||
c7743d02 HWN |
85 | j = SCM_NUM_PROTECTS; |
86 | while (j--) | |
87 | scm_gc_mark (scm_sys_protects[j]); | |
88 | ||
89 | /* mark the registered roots */ | |
90 | { | |
91 | size_t i; | |
c35738c1 | 92 | for (i = 0; i < SCM_HASHTABLE_N_BUCKETS (scm_gc_registered_roots); ++i) |
c7743d02 | 93 | { |
4057a3e0 | 94 | SCM l = SCM_HASHTABLE_BUCKET (scm_gc_registered_roots, i); |
d2e53ed6 | 95 | for (; !scm_is_null (l); l = SCM_CDR (l)) |
c7743d02 | 96 | { |
b9bd8526 | 97 | SCM *p = (SCM *) (scm_to_ulong (SCM_CAAR (l))); |
c7743d02 HWN |
98 | scm_gc_mark (*p); |
99 | } | |
100 | } | |
101 | } | |
eab1b259 | 102 | |
06c1d900 MV |
103 | scm_mark_subr_table (); |
104 | ||
71c7cfa5 | 105 | loops = 0; |
06c1d900 MV |
106 | while (1) |
107 | { | |
06c1d900 | 108 | int again; |
71c7cfa5 | 109 | loops++; |
06c1d900 MV |
110 | |
111 | /* Mark the non-weak references of weak vectors. For a weak key | |
112 | alist vector, this would mark the values for keys that are | |
113 | marked. We need to do this in a loop until everything | |
114 | settles down since the newly marked values might be keys in | |
115 | other weak key alist vectors, for example. | |
116 | */ | |
117 | again = scm_i_mark_weak_vectors_non_weaks (); | |
118 | if (again) | |
119 | continue; | |
120 | ||
121 | /* Now we scan all marked guardians and move all unmarked objects | |
122 | from the accessible to the inaccessible list. | |
123 | */ | |
124 | scm_i_identify_inaccessible_guardeds (); | |
125 | ||
126 | /* When we have identified all inaccessible objects, we can mark | |
127 | them. | |
128 | */ | |
129 | again = scm_i_mark_inaccessible_guardeds (); | |
130 | ||
131 | /* This marking might have changed the situation for weak vectors | |
132 | and might have turned up new guardians that need to be processed, | |
133 | so we do it all over again. | |
134 | */ | |
135 | if (again) | |
136 | continue; | |
137 | ||
138 | /* Nothing new marked in this round, we are done. | |
139 | */ | |
140 | break; | |
141 | } | |
142 | ||
06c1d900 | 143 | /* Remove all unmarked entries from the weak vectors. |
c7743d02 | 144 | */ |
06c1d900 MV |
145 | scm_i_remove_weaks_from_weak_vectors (); |
146 | ||
147 | /* Bring hashtables upto date. | |
148 | */ | |
149 | scm_i_scan_weak_hashtables (); | |
d09752ff | 150 | scm_i_marking = 0; |
c7743d02 HWN |
151 | } |
152 | ||
153 | /* {Mark/Sweep} | |
154 | */ | |
155 | ||
c7743d02 HWN |
156 | /* |
157 | Mark an object precisely, then recurse. | |
158 | */ | |
159 | void | |
160 | scm_gc_mark (SCM ptr) | |
161 | { | |
162 | if (SCM_IMP (ptr)) | |
45a1c3e8 | 163 | return; |
c7743d02 HWN |
164 | |
165 | if (SCM_GC_MARK_P (ptr)) | |
45a1c3e8 | 166 | return; |
c7743d02 HWN |
167 | |
168 | SCM_SET_GC_MARK (ptr); | |
169 | scm_gc_mark_dependencies (ptr); | |
170 | } | |
171 | ||
d09752ff HWN |
172 | void |
173 | ensure_marking (void) | |
174 | { | |
175 | assert (scm_i_marking); | |
176 | } | |
177 | ||
c7743d02 HWN |
178 | /* |
179 | ||
180 | Mark the dependencies of an object. | |
181 | ||
33138b05 | 182 | Prefetching: |
c7743d02 HWN |
183 | |
184 | Should prefetch objects before marking, i.e. if marking a cell, we | |
185 | should prefetch the car, and then mark the cdr. This will improve CPU | |
82ae1b8e | 186 | cache misses, because the car is more likely to be in cache when we |
c7743d02 HWN |
187 | finish the cdr. |
188 | ||
189 | See http://www.hpl.hp.com/techreports/2000/HPL-2000-99.pdf, reducing | |
190 | garbage collector cache misses. | |
191 | ||
192 | Prefetch is supported on GCC >= 3.1 | |
193 | ||
33138b05 HWN |
194 | (Some time later.) |
195 | ||
196 | Tried this with GCC 3.1.1 -- the time differences are barely measurable. | |
197 | Perhaps this would work better with an explicit markstack? | |
198 | ||
199 | ||
200 | */ | |
06c1d900 | 201 | |
c7743d02 HWN |
202 | void |
203 | scm_gc_mark_dependencies (SCM p) | |
204 | #define FUNC_NAME "scm_gc_mark_dependencies" | |
205 | { | |
206 | register long i; | |
207 | register SCM ptr; | |
702551e6 | 208 | SCM cell_type; |
c7743d02 HWN |
209 | |
210 | ptr = p; | |
211 | scm_mark_dependencies_again: | |
76da80e7 | 212 | |
c7743d02 HWN |
213 | cell_type = SCM_GC_CELL_TYPE (ptr); |
214 | switch (SCM_ITAG7 (cell_type)) | |
215 | { | |
216 | case scm_tcs_cons_nimcar: | |
217 | if (SCM_IMP (SCM_CDR (ptr))) | |
218 | { | |
219 | ptr = SCM_CAR (ptr); | |
220 | goto gc_mark_nimp; | |
221 | } | |
33138b05 HWN |
222 | |
223 | ||
c7743d02 HWN |
224 | scm_gc_mark (SCM_CAR (ptr)); |
225 | ptr = SCM_CDR (ptr); | |
226 | goto gc_mark_nimp; | |
227 | case scm_tcs_cons_imcar: | |
228 | ptr = SCM_CDR (ptr); | |
229 | goto gc_mark_loop; | |
230 | case scm_tc7_pws: | |
33138b05 | 231 | |
c7743d02 HWN |
232 | scm_gc_mark (SCM_SETTER (ptr)); |
233 | ptr = SCM_PROCEDURE (ptr); | |
234 | goto gc_mark_loop; | |
235 | case scm_tcs_struct: | |
236 | { | |
237 | /* XXX - use less explicit code. */ | |
238 | scm_t_bits word0 = SCM_CELL_WORD_0 (ptr) - scm_tc3_struct; | |
239 | scm_t_bits * vtable_data = (scm_t_bits *) word0; | |
240 | SCM layout = SCM_PACK (vtable_data [scm_vtable_index_layout]); | |
eb01cb64 MV |
241 | long len = scm_i_symbol_length (layout); |
242 | const char *fields_desc = scm_i_symbol_chars (layout); | |
243 | scm_t_bits *struct_data = (scm_t_bits *) SCM_STRUCT_DATA (ptr); | |
c7743d02 HWN |
244 | |
245 | if (vtable_data[scm_struct_i_flags] & SCM_STRUCTF_ENTITY) | |
246 | { | |
247 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_procedure])); | |
248 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_setter])); | |
249 | } | |
250 | if (len) | |
251 | { | |
252 | long x; | |
253 | ||
254 | for (x = 0; x < len - 2; x += 2, ++struct_data) | |
255 | if (fields_desc[x] == 'p') | |
256 | scm_gc_mark (SCM_PACK (*struct_data)); | |
257 | if (fields_desc[x] == 'p') | |
258 | { | |
259 | if (SCM_LAYOUT_TAILP (fields_desc[x + 1])) | |
260 | for (x = *struct_data++; x; --x, ++struct_data) | |
261 | scm_gc_mark (SCM_PACK (*struct_data)); | |
262 | else | |
263 | scm_gc_mark (SCM_PACK (*struct_data)); | |
264 | } | |
265 | } | |
266 | /* mark vtable */ | |
267 | ptr = SCM_PACK (vtable_data [scm_vtable_index_vtable]); | |
268 | goto gc_mark_loop; | |
269 | } | |
270 | break; | |
271 | case scm_tcs_closures: | |
272 | if (SCM_IMP (SCM_ENV (ptr))) | |
273 | { | |
274 | ptr = SCM_CLOSCAR (ptr); | |
275 | goto gc_mark_nimp; | |
276 | } | |
277 | scm_gc_mark (SCM_CLOSCAR (ptr)); | |
278 | ptr = SCM_ENV (ptr); | |
279 | goto gc_mark_nimp; | |
280 | case scm_tc7_vector: | |
4057a3e0 | 281 | i = SCM_SIMPLE_VECTOR_LENGTH (ptr); |
c7743d02 HWN |
282 | if (i == 0) |
283 | break; | |
284 | while (--i > 0) | |
33138b05 | 285 | { |
4057a3e0 MV |
286 | SCM elt = SCM_SIMPLE_VECTOR_REF (ptr, i); |
287 | if (SCM_NIMP (elt)) | |
288 | scm_gc_mark (elt); | |
33138b05 | 289 | } |
4057a3e0 | 290 | ptr = SCM_SIMPLE_VECTOR_REF (ptr, 0); |
c7743d02 HWN |
291 | goto gc_mark_loop; |
292 | #ifdef CCLO | |
293 | case scm_tc7_cclo: | |
294 | { | |
295 | size_t i = SCM_CCLO_LENGTH (ptr); | |
296 | size_t j; | |
297 | for (j = 1; j != i; ++j) | |
298 | { | |
299 | SCM obj = SCM_CCLO_REF (ptr, j); | |
300 | if (!SCM_IMP (obj)) | |
301 | scm_gc_mark (obj); | |
302 | } | |
303 | ptr = SCM_CCLO_REF (ptr, 0); | |
304 | goto gc_mark_loop; | |
305 | } | |
306 | #endif | |
eb01cb64 | 307 | |
c7743d02 | 308 | case scm_tc7_string: |
eb01cb64 MV |
309 | ptr = scm_i_string_mark (ptr); |
310 | goto gc_mark_loop; | |
311 | case scm_tc7_stringbuf: | |
312 | ptr = scm_i_stringbuf_mark (ptr); | |
313 | goto gc_mark_loop; | |
c7743d02 | 314 | |
534c55a9 | 315 | case scm_tc7_number: |
f92e85f7 MV |
316 | if (SCM_TYP16 (ptr) == scm_tc16_fraction) |
317 | { | |
318 | scm_gc_mark (SCM_CELL_OBJECT_1 (ptr)); | |
319 | ptr = SCM_CELL_OBJECT_2 (ptr); | |
320 | goto gc_mark_loop; | |
321 | } | |
534c55a9 DH |
322 | break; |
323 | ||
c7743d02 | 324 | case scm_tc7_wvect: |
06c1d900 | 325 | scm_i_mark_weak_vector (ptr); |
c7743d02 HWN |
326 | break; |
327 | ||
328 | case scm_tc7_symbol: | |
eb01cb64 | 329 | ptr = scm_i_symbol_mark (ptr); |
c7743d02 HWN |
330 | goto gc_mark_loop; |
331 | case scm_tc7_variable: | |
332 | ptr = SCM_CELL_OBJECT_1 (ptr); | |
333 | goto gc_mark_loop; | |
334 | case scm_tcs_subrs: | |
335 | break; | |
336 | case scm_tc7_port: | |
337 | i = SCM_PTOBNUM (ptr); | |
338 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
339 | if (!(i < scm_numptob)) | |
be3ff021 HWN |
340 | { |
341 | fprintf (stderr, "undefined port type"); | |
342 | abort(); | |
343 | } | |
c7743d02 HWN |
344 | #endif |
345 | if (SCM_PTAB_ENTRY(ptr)) | |
346 | scm_gc_mark (SCM_FILENAME (ptr)); | |
347 | if (scm_ptobs[i].mark) | |
348 | { | |
349 | ptr = (scm_ptobs[i].mark) (ptr); | |
350 | goto gc_mark_loop; | |
351 | } | |
352 | else | |
353 | return; | |
354 | break; | |
355 | case scm_tc7_smob: | |
356 | switch (SCM_TYP16 (ptr)) | |
357 | { /* should be faster than going through scm_smobs */ | |
358 | case scm_tc_free_cell: | |
359 | /* We have detected a free cell. This can happen if non-object data | |
360 | * on the C stack points into guile's heap and is scanned during | |
361 | * conservative marking. */ | |
362 | break; | |
c7743d02 HWN |
363 | default: |
364 | i = SCM_SMOBNUM (ptr); | |
365 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
366 | if (!(i < scm_numsmob)) | |
be3ff021 HWN |
367 | { |
368 | fprintf (stderr, "undefined smob type"); | |
369 | abort(); | |
370 | } | |
c7743d02 HWN |
371 | #endif |
372 | if (scm_smobs[i].mark) | |
373 | { | |
374 | ptr = (scm_smobs[i].mark) (ptr); | |
375 | goto gc_mark_loop; | |
376 | } | |
377 | else | |
378 | return; | |
379 | } | |
380 | break; | |
381 | default: | |
be3ff021 HWN |
382 | fprintf (stderr, "unknown type"); |
383 | abort(); | |
c7743d02 HWN |
384 | } |
385 | ||
386 | /* | |
387 | If we got here, then exhausted recursion options for PTR. we | |
388 | return (careful not to mark PTR, it might be the argument that we | |
389 | were called with.) | |
390 | */ | |
391 | return ; | |
06c1d900 MV |
392 | |
393 | gc_mark_loop: | |
c7743d02 HWN |
394 | if (SCM_IMP (ptr)) |
395 | return; | |
396 | ||
397 | gc_mark_nimp: | |
398 | { | |
399 | int valid_cell = CELL_P (ptr); | |
400 | ||
401 | ||
402 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
403 | if (scm_debug_cell_accesses_p) | |
404 | { | |
405 | /* We are in debug mode. Check the ptr exhaustively. */ | |
406 | ||
40945e5e | 407 | valid_cell = valid_cell && scm_in_heap_p (ptr); |
c7743d02 HWN |
408 | } |
409 | ||
410 | #endif | |
411 | if (!valid_cell) | |
be3ff021 HWN |
412 | { |
413 | fprintf (stderr, "rogue pointer in heap"); | |
414 | abort(); | |
415 | } | |
c7743d02 | 416 | } |
eab1b259 | 417 | |
82ae1b8e | 418 | if (SCM_GC_MARK_P (ptr)) |
76da80e7 | 419 | return; |
a54a94b3 | 420 | |
76da80e7 | 421 | SCM_SET_GC_MARK (ptr); |
eab1b259 | 422 | |
76da80e7 | 423 | goto scm_mark_dependencies_again; |
c7743d02 HWN |
424 | |
425 | } | |
426 | #undef FUNC_NAME | |
427 | ||
428 | ||
c7743d02 HWN |
429 | /* Mark a region conservatively */ |
430 | void | |
431 | scm_mark_locations (SCM_STACKITEM x[], unsigned long n) | |
432 | { | |
433 | unsigned long m; | |
434 | ||
435 | for (m = 0; m < n; ++m) | |
436 | { | |
437 | SCM obj = * (SCM *) &x[m]; | |
438 | long int segment = scm_i_find_heap_segment_containing_object (obj); | |
439 | if (segment >= 0) | |
440 | scm_gc_mark (obj); | |
441 | } | |
442 | } | |
443 | ||
444 | ||
445 | /* The function scm_in_heap_p determines whether an SCM value can be regarded as a | |
446 | * pointer to a cell on the heap. | |
447 | */ | |
448 | int | |
449 | scm_in_heap_p (SCM value) | |
450 | { | |
451 | long int segment = scm_i_find_heap_segment_containing_object (value); | |
452 | return (segment >= 0); | |
453 | } | |
454 | ||
455 | ||
456 | #if SCM_ENABLE_DEPRECATED == 1 | |
457 | ||
458 | /* If an allocated cell is detected during garbage collection, this | |
459 | * means that some code has just obtained the object but was preempted | |
460 | * before the initialization of the object was completed. This meanst | |
461 | * that some entries of the allocated cell may already contain SCM | |
462 | * objects. Therefore, allocated cells are scanned conservatively. | |
463 | */ | |
464 | ||
465 | scm_t_bits scm_tc16_allocated; | |
466 | ||
467 | static SCM | |
468 | allocated_mark (SCM cell) | |
469 | { | |
470 | unsigned long int cell_segment = scm_i_find_heap_segment_containing_object (cell); | |
471 | unsigned int span = scm_i_heap_segment_table[cell_segment]->span; | |
472 | unsigned int i; | |
473 | ||
474 | for (i = 1; i != span * 2; ++i) | |
475 | { | |
476 | SCM obj = SCM_CELL_OBJECT (cell, i); | |
477 | long int obj_segment = scm_i_find_heap_segment_containing_object (obj); | |
478 | if (obj_segment >= 0) | |
479 | scm_gc_mark (obj); | |
480 | } | |
481 | return SCM_BOOL_F; | |
482 | } | |
483 | ||
484 | SCM | |
485 | scm_deprecated_newcell (void) | |
486 | { | |
487 | scm_c_issue_deprecation_warning | |
488 | ("SCM_NEWCELL is deprecated. Use `scm_cell' instead.\n"); | |
489 | ||
490 | return scm_cell (scm_tc16_allocated, 0); | |
491 | } | |
492 | ||
493 | SCM | |
494 | scm_deprecated_newcell2 (void) | |
495 | { | |
496 | scm_c_issue_deprecation_warning | |
497 | ("SCM_NEWCELL2 is deprecated. Use `scm_double_cell' instead.\n"); | |
498 | ||
499 | return scm_double_cell (scm_tc16_allocated, 0, 0, 0); | |
500 | } | |
501 | ||
502 | #endif /* SCM_ENABLE_DEPRECATED == 1 */ | |
503 | ||
504 | ||
505 | void | |
506 | scm_gc_init_mark(void) | |
507 | { | |
508 | #if SCM_ENABLE_DEPRECATED == 1 | |
509 | scm_tc16_allocated = scm_make_smob_type ("allocated cell", 0); | |
510 | scm_set_smob_mark (scm_tc16_allocated, allocated_mark); | |
511 | #endif | |
512 | } | |
513 |