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 MV |
75 | |
76 | scm_i_init_weak_vectors_for_gc (); | |
77 | scm_i_init_guardians_for_gc (); | |
c7743d02 HWN |
78 | |
79 | scm_i_clear_mark_space (); | |
eab1b259 | 80 | |
c7743d02 HWN |
81 | /* Mark every thread's stack and registers */ |
82 | scm_threads_mark_stacks (); | |
83 | ||
c7743d02 HWN |
84 | j = SCM_NUM_PROTECTS; |
85 | while (j--) | |
86 | scm_gc_mark (scm_sys_protects[j]); | |
87 | ||
88 | /* mark the registered roots */ | |
89 | { | |
90 | size_t i; | |
c35738c1 | 91 | for (i = 0; i < SCM_HASHTABLE_N_BUCKETS (scm_gc_registered_roots); ++i) |
c7743d02 | 92 | { |
4057a3e0 | 93 | SCM l = SCM_HASHTABLE_BUCKET (scm_gc_registered_roots, i); |
d2e53ed6 | 94 | for (; !scm_is_null (l); l = SCM_CDR (l)) |
c7743d02 | 95 | { |
b9bd8526 | 96 | SCM *p = (SCM *) (scm_to_ulong (SCM_CAAR (l))); |
c7743d02 HWN |
97 | scm_gc_mark (*p); |
98 | } | |
99 | } | |
100 | } | |
eab1b259 | 101 | |
06c1d900 MV |
102 | scm_mark_subr_table (); |
103 | ||
71c7cfa5 | 104 | loops = 0; |
06c1d900 MV |
105 | while (1) |
106 | { | |
06c1d900 | 107 | int again; |
71c7cfa5 | 108 | loops++; |
06c1d900 MV |
109 | |
110 | /* Mark the non-weak references of weak vectors. For a weak key | |
111 | alist vector, this would mark the values for keys that are | |
112 | marked. We need to do this in a loop until everything | |
113 | settles down since the newly marked values might be keys in | |
114 | other weak key alist vectors, for example. | |
115 | */ | |
116 | again = scm_i_mark_weak_vectors_non_weaks (); | |
117 | if (again) | |
118 | continue; | |
119 | ||
120 | /* Now we scan all marked guardians and move all unmarked objects | |
121 | from the accessible to the inaccessible list. | |
122 | */ | |
123 | scm_i_identify_inaccessible_guardeds (); | |
124 | ||
125 | /* When we have identified all inaccessible objects, we can mark | |
126 | them. | |
127 | */ | |
128 | again = scm_i_mark_inaccessible_guardeds (); | |
129 | ||
130 | /* This marking might have changed the situation for weak vectors | |
131 | and might have turned up new guardians that need to be processed, | |
132 | so we do it all over again. | |
133 | */ | |
134 | if (again) | |
135 | continue; | |
136 | ||
137 | /* Nothing new marked in this round, we are done. | |
138 | */ | |
139 | break; | |
140 | } | |
141 | ||
1f65cc17 | 142 | /* fprintf (stderr, "%d loops\n", loops); */ |
c7743d02 | 143 | |
06c1d900 | 144 | /* Remove all unmarked entries from the weak vectors. |
c7743d02 | 145 | */ |
06c1d900 MV |
146 | scm_i_remove_weaks_from_weak_vectors (); |
147 | ||
148 | /* Bring hashtables upto date. | |
149 | */ | |
150 | scm_i_scan_weak_hashtables (); | |
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 | ||
172 | /* | |
173 | ||
174 | Mark the dependencies of an object. | |
175 | ||
33138b05 | 176 | Prefetching: |
c7743d02 HWN |
177 | |
178 | Should prefetch objects before marking, i.e. if marking a cell, we | |
179 | should prefetch the car, and then mark the cdr. This will improve CPU | |
180 | cache misses, because the car is more likely to be in core when we | |
181 | finish the cdr. | |
182 | ||
183 | See http://www.hpl.hp.com/techreports/2000/HPL-2000-99.pdf, reducing | |
184 | garbage collector cache misses. | |
185 | ||
186 | Prefetch is supported on GCC >= 3.1 | |
187 | ||
33138b05 HWN |
188 | (Some time later.) |
189 | ||
190 | Tried this with GCC 3.1.1 -- the time differences are barely measurable. | |
191 | Perhaps this would work better with an explicit markstack? | |
192 | ||
193 | ||
194 | */ | |
06c1d900 | 195 | |
c7743d02 HWN |
196 | void |
197 | scm_gc_mark_dependencies (SCM p) | |
198 | #define FUNC_NAME "scm_gc_mark_dependencies" | |
199 | { | |
200 | register long i; | |
201 | register SCM ptr; | |
702551e6 | 202 | SCM cell_type; |
c7743d02 HWN |
203 | |
204 | ptr = p; | |
205 | scm_mark_dependencies_again: | |
76da80e7 | 206 | |
c7743d02 HWN |
207 | cell_type = SCM_GC_CELL_TYPE (ptr); |
208 | switch (SCM_ITAG7 (cell_type)) | |
209 | { | |
210 | case scm_tcs_cons_nimcar: | |
211 | if (SCM_IMP (SCM_CDR (ptr))) | |
212 | { | |
213 | ptr = SCM_CAR (ptr); | |
214 | goto gc_mark_nimp; | |
215 | } | |
33138b05 HWN |
216 | |
217 | ||
c7743d02 HWN |
218 | scm_gc_mark (SCM_CAR (ptr)); |
219 | ptr = SCM_CDR (ptr); | |
220 | goto gc_mark_nimp; | |
221 | case scm_tcs_cons_imcar: | |
222 | ptr = SCM_CDR (ptr); | |
223 | goto gc_mark_loop; | |
224 | case scm_tc7_pws: | |
33138b05 | 225 | |
c7743d02 HWN |
226 | scm_gc_mark (SCM_SETTER (ptr)); |
227 | ptr = SCM_PROCEDURE (ptr); | |
228 | goto gc_mark_loop; | |
229 | case scm_tcs_struct: | |
230 | { | |
231 | /* XXX - use less explicit code. */ | |
232 | scm_t_bits word0 = SCM_CELL_WORD_0 (ptr) - scm_tc3_struct; | |
233 | scm_t_bits * vtable_data = (scm_t_bits *) word0; | |
234 | SCM layout = SCM_PACK (vtable_data [scm_vtable_index_layout]); | |
eb01cb64 MV |
235 | long len = scm_i_symbol_length (layout); |
236 | const char *fields_desc = scm_i_symbol_chars (layout); | |
237 | scm_t_bits *struct_data = (scm_t_bits *) SCM_STRUCT_DATA (ptr); | |
c7743d02 HWN |
238 | |
239 | if (vtable_data[scm_struct_i_flags] & SCM_STRUCTF_ENTITY) | |
240 | { | |
241 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_procedure])); | |
242 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_setter])); | |
243 | } | |
244 | if (len) | |
245 | { | |
246 | long x; | |
247 | ||
248 | for (x = 0; x < len - 2; x += 2, ++struct_data) | |
249 | if (fields_desc[x] == 'p') | |
250 | scm_gc_mark (SCM_PACK (*struct_data)); | |
251 | if (fields_desc[x] == 'p') | |
252 | { | |
253 | if (SCM_LAYOUT_TAILP (fields_desc[x + 1])) | |
254 | for (x = *struct_data++; x; --x, ++struct_data) | |
255 | scm_gc_mark (SCM_PACK (*struct_data)); | |
256 | else | |
257 | scm_gc_mark (SCM_PACK (*struct_data)); | |
258 | } | |
259 | } | |
260 | /* mark vtable */ | |
261 | ptr = SCM_PACK (vtable_data [scm_vtable_index_vtable]); | |
262 | goto gc_mark_loop; | |
263 | } | |
264 | break; | |
265 | case scm_tcs_closures: | |
266 | if (SCM_IMP (SCM_ENV (ptr))) | |
267 | { | |
268 | ptr = SCM_CLOSCAR (ptr); | |
269 | goto gc_mark_nimp; | |
270 | } | |
271 | scm_gc_mark (SCM_CLOSCAR (ptr)); | |
272 | ptr = SCM_ENV (ptr); | |
273 | goto gc_mark_nimp; | |
274 | case scm_tc7_vector: | |
4057a3e0 | 275 | i = SCM_SIMPLE_VECTOR_LENGTH (ptr); |
c7743d02 HWN |
276 | if (i == 0) |
277 | break; | |
278 | while (--i > 0) | |
33138b05 | 279 | { |
4057a3e0 MV |
280 | SCM elt = SCM_SIMPLE_VECTOR_REF (ptr, i); |
281 | if (SCM_NIMP (elt)) | |
282 | scm_gc_mark (elt); | |
33138b05 | 283 | } |
4057a3e0 | 284 | ptr = SCM_SIMPLE_VECTOR_REF (ptr, 0); |
c7743d02 HWN |
285 | goto gc_mark_loop; |
286 | #ifdef CCLO | |
287 | case scm_tc7_cclo: | |
288 | { | |
289 | size_t i = SCM_CCLO_LENGTH (ptr); | |
290 | size_t j; | |
291 | for (j = 1; j != i; ++j) | |
292 | { | |
293 | SCM obj = SCM_CCLO_REF (ptr, j); | |
294 | if (!SCM_IMP (obj)) | |
295 | scm_gc_mark (obj); | |
296 | } | |
297 | ptr = SCM_CCLO_REF (ptr, 0); | |
298 | goto gc_mark_loop; | |
299 | } | |
300 | #endif | |
eb01cb64 | 301 | |
c7743d02 | 302 | case scm_tc7_string: |
eb01cb64 MV |
303 | ptr = scm_i_string_mark (ptr); |
304 | goto gc_mark_loop; | |
305 | case scm_tc7_stringbuf: | |
306 | ptr = scm_i_stringbuf_mark (ptr); | |
307 | goto gc_mark_loop; | |
c7743d02 | 308 | |
534c55a9 | 309 | case scm_tc7_number: |
f92e85f7 MV |
310 | if (SCM_TYP16 (ptr) == scm_tc16_fraction) |
311 | { | |
312 | scm_gc_mark (SCM_CELL_OBJECT_1 (ptr)); | |
313 | ptr = SCM_CELL_OBJECT_2 (ptr); | |
314 | goto gc_mark_loop; | |
315 | } | |
534c55a9 DH |
316 | break; |
317 | ||
c7743d02 | 318 | case scm_tc7_wvect: |
06c1d900 | 319 | scm_i_mark_weak_vector (ptr); |
c7743d02 HWN |
320 | break; |
321 | ||
322 | case scm_tc7_symbol: | |
eb01cb64 | 323 | ptr = scm_i_symbol_mark (ptr); |
c7743d02 HWN |
324 | goto gc_mark_loop; |
325 | case scm_tc7_variable: | |
326 | ptr = SCM_CELL_OBJECT_1 (ptr); | |
327 | goto gc_mark_loop; | |
328 | case scm_tcs_subrs: | |
329 | break; | |
330 | case scm_tc7_port: | |
331 | i = SCM_PTOBNUM (ptr); | |
332 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
333 | if (!(i < scm_numptob)) | |
be3ff021 HWN |
334 | { |
335 | fprintf (stderr, "undefined port type"); | |
336 | abort(); | |
337 | } | |
c7743d02 HWN |
338 | #endif |
339 | if (SCM_PTAB_ENTRY(ptr)) | |
340 | scm_gc_mark (SCM_FILENAME (ptr)); | |
341 | if (scm_ptobs[i].mark) | |
342 | { | |
343 | ptr = (scm_ptobs[i].mark) (ptr); | |
344 | goto gc_mark_loop; | |
345 | } | |
346 | else | |
347 | return; | |
348 | break; | |
349 | case scm_tc7_smob: | |
350 | switch (SCM_TYP16 (ptr)) | |
351 | { /* should be faster than going through scm_smobs */ | |
352 | case scm_tc_free_cell: | |
353 | /* We have detected a free cell. This can happen if non-object data | |
354 | * on the C stack points into guile's heap and is scanned during | |
355 | * conservative marking. */ | |
356 | break; | |
c7743d02 HWN |
357 | default: |
358 | i = SCM_SMOBNUM (ptr); | |
359 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
360 | if (!(i < scm_numsmob)) | |
be3ff021 HWN |
361 | { |
362 | fprintf (stderr, "undefined smob type"); | |
363 | abort(); | |
364 | } | |
c7743d02 HWN |
365 | #endif |
366 | if (scm_smobs[i].mark) | |
367 | { | |
368 | ptr = (scm_smobs[i].mark) (ptr); | |
369 | goto gc_mark_loop; | |
370 | } | |
371 | else | |
372 | return; | |
373 | } | |
374 | break; | |
375 | default: | |
be3ff021 HWN |
376 | fprintf (stderr, "unknown type"); |
377 | abort(); | |
c7743d02 HWN |
378 | } |
379 | ||
380 | /* | |
381 | If we got here, then exhausted recursion options for PTR. we | |
382 | return (careful not to mark PTR, it might be the argument that we | |
383 | were called with.) | |
384 | */ | |
385 | return ; | |
06c1d900 MV |
386 | |
387 | gc_mark_loop: | |
c7743d02 HWN |
388 | if (SCM_IMP (ptr)) |
389 | return; | |
390 | ||
391 | gc_mark_nimp: | |
392 | { | |
393 | int valid_cell = CELL_P (ptr); | |
394 | ||
395 | ||
396 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
397 | if (scm_debug_cell_accesses_p) | |
398 | { | |
399 | /* We are in debug mode. Check the ptr exhaustively. */ | |
400 | ||
401 | valid_cell = valid_cell && (scm_i_find_heap_segment_containing_object (ptr) >= 0); | |
402 | } | |
403 | ||
404 | #endif | |
405 | if (!valid_cell) | |
be3ff021 HWN |
406 | { |
407 | fprintf (stderr, "rogue pointer in heap"); | |
408 | abort(); | |
409 | } | |
c7743d02 | 410 | } |
eab1b259 | 411 | |
76da80e7 MV |
412 | if (SCM_GC_MARK_P (ptr)) |
413 | { | |
414 | return; | |
415 | } | |
a54a94b3 | 416 | |
76da80e7 | 417 | SCM_SET_GC_MARK (ptr); |
eab1b259 | 418 | |
76da80e7 | 419 | goto scm_mark_dependencies_again; |
c7743d02 HWN |
420 | |
421 | } | |
422 | #undef FUNC_NAME | |
423 | ||
424 | ||
425 | ||
eab1b259 | 426 | |
c7743d02 HWN |
427 | /* Mark a region conservatively */ |
428 | void | |
429 | scm_mark_locations (SCM_STACKITEM x[], unsigned long n) | |
430 | { | |
431 | unsigned long m; | |
432 | ||
433 | for (m = 0; m < n; ++m) | |
434 | { | |
435 | SCM obj = * (SCM *) &x[m]; | |
436 | long int segment = scm_i_find_heap_segment_containing_object (obj); | |
437 | if (segment >= 0) | |
438 | scm_gc_mark (obj); | |
439 | } | |
440 | } | |
441 | ||
442 | ||
443 | /* The function scm_in_heap_p determines whether an SCM value can be regarded as a | |
444 | * pointer to a cell on the heap. | |
445 | */ | |
446 | int | |
447 | scm_in_heap_p (SCM value) | |
448 | { | |
449 | long int segment = scm_i_find_heap_segment_containing_object (value); | |
450 | return (segment >= 0); | |
451 | } | |
452 | ||
453 | ||
454 | #if SCM_ENABLE_DEPRECATED == 1 | |
455 | ||
456 | /* If an allocated cell is detected during garbage collection, this | |
457 | * means that some code has just obtained the object but was preempted | |
458 | * before the initialization of the object was completed. This meanst | |
459 | * that some entries of the allocated cell may already contain SCM | |
460 | * objects. Therefore, allocated cells are scanned conservatively. | |
461 | */ | |
462 | ||
463 | scm_t_bits scm_tc16_allocated; | |
464 | ||
465 | static SCM | |
466 | allocated_mark (SCM cell) | |
467 | { | |
468 | unsigned long int cell_segment = scm_i_find_heap_segment_containing_object (cell); | |
469 | unsigned int span = scm_i_heap_segment_table[cell_segment]->span; | |
470 | unsigned int i; | |
471 | ||
472 | for (i = 1; i != span * 2; ++i) | |
473 | { | |
474 | SCM obj = SCM_CELL_OBJECT (cell, i); | |
475 | long int obj_segment = scm_i_find_heap_segment_containing_object (obj); | |
476 | if (obj_segment >= 0) | |
477 | scm_gc_mark (obj); | |
478 | } | |
479 | return SCM_BOOL_F; | |
480 | } | |
481 | ||
482 | SCM | |
483 | scm_deprecated_newcell (void) | |
484 | { | |
485 | scm_c_issue_deprecation_warning | |
486 | ("SCM_NEWCELL is deprecated. Use `scm_cell' instead.\n"); | |
487 | ||
488 | return scm_cell (scm_tc16_allocated, 0); | |
489 | } | |
490 | ||
491 | SCM | |
492 | scm_deprecated_newcell2 (void) | |
493 | { | |
494 | scm_c_issue_deprecation_warning | |
495 | ("SCM_NEWCELL2 is deprecated. Use `scm_double_cell' instead.\n"); | |
496 | ||
497 | return scm_double_cell (scm_tc16_allocated, 0, 0, 0); | |
498 | } | |
499 | ||
500 | #endif /* SCM_ENABLE_DEPRECATED == 1 */ | |
501 | ||
502 | ||
503 | void | |
504 | scm_gc_init_mark(void) | |
505 | { | |
506 | #if SCM_ENABLE_DEPRECATED == 1 | |
507 | scm_tc16_allocated = scm_make_smob_type ("allocated cell", 0); | |
508 | scm_set_smob_mark (scm_tc16_allocated, allocated_mark); | |
509 | #endif | |
510 | } | |
511 |