Commit | Line | Data |
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ac51e74b | 1 | /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 2004, 2005, 2006, 2009 Free Software Foundation, Inc. |
c7743d02 | 2 | * |
73be1d9e | 3 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
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. | |
c7743d02 | 7 | * |
53befeb7 NJ |
8 | * This library is distributed in the hope that it will be useful, but |
9 | * 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 | |
53befeb7 NJ |
15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
16 | * 02110-1301 USA | |
73be1d9e | 17 | */ |
c7743d02 HWN |
18 | |
19 | ||
20 | \f | |
dbb605f5 | 21 | #ifdef HAVE_CONFIG_H |
3ba436c8 RB |
22 | # include <config.h> |
23 | #endif | |
24 | ||
c7743d02 HWN |
25 | #include <stdio.h> |
26 | #include <errno.h> | |
27 | #include <string.h> | |
28 | #include <assert.h> | |
29 | ||
30 | #ifdef __ia64__ | |
31 | #include <ucontext.h> | |
32 | extern unsigned long * __libc_ia64_register_backing_store_base; | |
33 | #endif | |
34 | ||
35 | #include "libguile/_scm.h" | |
36 | #include "libguile/eval.h" | |
37 | #include "libguile/stime.h" | |
38 | #include "libguile/stackchk.h" | |
39 | #include "libguile/struct.h" | |
40 | #include "libguile/smob.h" | |
41 | #include "libguile/unif.h" | |
42 | #include "libguile/async.h" | |
43 | #include "libguile/ports.h" | |
44 | #include "libguile/root.h" | |
45 | #include "libguile/strings.h" | |
46 | #include "libguile/vectors.h" | |
47 | #include "libguile/weaks.h" | |
48 | #include "libguile/hashtab.h" | |
49 | #include "libguile/tags.h" | |
50 | #include "libguile/private-gc.h" | |
51 | #include "libguile/validate.h" | |
52 | #include "libguile/deprecation.h" | |
53 | #include "libguile/gc.h" | |
06c1d900 | 54 | #include "libguile/guardians.h" |
c7743d02 HWN |
55 | |
56 | #ifdef GUILE_DEBUG_MALLOC | |
57 | #include "libguile/debug-malloc.h" | |
58 | #endif | |
59 | ||
60 | #ifdef HAVE_MALLOC_H | |
61 | #include <malloc.h> | |
62 | #endif | |
63 | ||
64 | #ifdef HAVE_UNISTD_H | |
65 | #include <unistd.h> | |
66 | #endif | |
67 | ||
6cc323e2 LC |
68 | int scm_i_marking = 0; |
69 | ||
c7743d02 HWN |
70 | /* |
71 | Entry point for this file. | |
72 | */ | |
73 | void | |
74 | scm_mark_all (void) | |
75 | { | |
76 | long j; | |
71c7cfa5 | 77 | int loops; |
06c1d900 | 78 | |
d09752ff | 79 | scm_i_marking = 1; |
06c1d900 MV |
80 | scm_i_init_weak_vectors_for_gc (); |
81 | scm_i_init_guardians_for_gc (); | |
c7743d02 HWN |
82 | |
83 | scm_i_clear_mark_space (); | |
40945e5e | 84 | scm_i_find_heap_calls = 0; |
c7743d02 HWN |
85 | /* Mark every thread's stack and registers */ |
86 | scm_threads_mark_stacks (); | |
87 | ||
c7743d02 HWN |
88 | j = SCM_NUM_PROTECTS; |
89 | while (j--) | |
90 | scm_gc_mark (scm_sys_protects[j]); | |
91 | ||
92 | /* mark the registered roots */ | |
93 | { | |
94 | size_t i; | |
c35738c1 | 95 | for (i = 0; i < SCM_HASHTABLE_N_BUCKETS (scm_gc_registered_roots); ++i) |
c7743d02 | 96 | { |
4057a3e0 | 97 | SCM l = SCM_HASHTABLE_BUCKET (scm_gc_registered_roots, i); |
d2e53ed6 | 98 | for (; !scm_is_null (l); l = SCM_CDR (l)) |
c7743d02 | 99 | { |
b9bd8526 | 100 | SCM *p = (SCM *) (scm_to_ulong (SCM_CAAR (l))); |
c7743d02 HWN |
101 | scm_gc_mark (*p); |
102 | } | |
103 | } | |
104 | } | |
06c1d900 | 105 | |
71c7cfa5 | 106 | loops = 0; |
06c1d900 MV |
107 | while (1) |
108 | { | |
06c1d900 | 109 | int again; |
71c7cfa5 | 110 | loops++; |
06c1d900 MV |
111 | |
112 | /* Mark the non-weak references of weak vectors. For a weak key | |
113 | alist vector, this would mark the values for keys that are | |
114 | marked. We need to do this in a loop until everything | |
115 | settles down since the newly marked values might be keys in | |
116 | other weak key alist vectors, for example. | |
117 | */ | |
118 | again = scm_i_mark_weak_vectors_non_weaks (); | |
119 | if (again) | |
120 | continue; | |
121 | ||
122 | /* Now we scan all marked guardians and move all unmarked objects | |
123 | from the accessible to the inaccessible list. | |
124 | */ | |
125 | scm_i_identify_inaccessible_guardeds (); | |
126 | ||
127 | /* When we have identified all inaccessible objects, we can mark | |
128 | them. | |
129 | */ | |
130 | again = scm_i_mark_inaccessible_guardeds (); | |
131 | ||
132 | /* This marking might have changed the situation for weak vectors | |
133 | and might have turned up new guardians that need to be processed, | |
134 | so we do it all over again. | |
135 | */ | |
136 | if (again) | |
137 | continue; | |
138 | ||
139 | /* Nothing new marked in this round, we are done. | |
140 | */ | |
141 | break; | |
142 | } | |
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 (); | |
d09752ff | 151 | scm_i_marking = 0; |
c7743d02 HWN |
152 | } |
153 | ||
154 | /* {Mark/Sweep} | |
155 | */ | |
156 | ||
c7743d02 HWN |
157 | /* |
158 | Mark an object precisely, then recurse. | |
159 | */ | |
160 | void | |
161 | scm_gc_mark (SCM ptr) | |
162 | { | |
163 | if (SCM_IMP (ptr)) | |
45a1c3e8 | 164 | return; |
c7743d02 HWN |
165 | |
166 | if (SCM_GC_MARK_P (ptr)) | |
45a1c3e8 | 167 | return; |
c7743d02 | 168 | |
7ddb9baf HWN |
169 | if (!scm_i_marking) |
170 | { | |
171 | static const char msg[] | |
172 | = "Should only call scm_gc_mark() during GC."; | |
173 | scm_c_issue_deprecation_warning (msg); | |
174 | } | |
175 | ||
c7743d02 HWN |
176 | SCM_SET_GC_MARK (ptr); |
177 | scm_gc_mark_dependencies (ptr); | |
178 | } | |
179 | ||
d09752ff | 180 | void |
7ddb9baf | 181 | scm_i_ensure_marking (void) |
d09752ff HWN |
182 | { |
183 | assert (scm_i_marking); | |
184 | } | |
185 | ||
c7743d02 HWN |
186 | /* |
187 | ||
188 | Mark the dependencies of an object. | |
189 | ||
33138b05 | 190 | Prefetching: |
c7743d02 HWN |
191 | |
192 | Should prefetch objects before marking, i.e. if marking a cell, we | |
193 | should prefetch the car, and then mark the cdr. This will improve CPU | |
82ae1b8e | 194 | cache misses, because the car is more likely to be in cache when we |
c7743d02 HWN |
195 | finish the cdr. |
196 | ||
197 | See http://www.hpl.hp.com/techreports/2000/HPL-2000-99.pdf, reducing | |
198 | garbage collector cache misses. | |
199 | ||
200 | Prefetch is supported on GCC >= 3.1 | |
201 | ||
33138b05 HWN |
202 | (Some time later.) |
203 | ||
204 | Tried this with GCC 3.1.1 -- the time differences are barely measurable. | |
205 | Perhaps this would work better with an explicit markstack? | |
206 | ||
207 | ||
208 | */ | |
06c1d900 | 209 | |
c7743d02 HWN |
210 | void |
211 | scm_gc_mark_dependencies (SCM p) | |
212 | #define FUNC_NAME "scm_gc_mark_dependencies" | |
213 | { | |
214 | register long i; | |
215 | register SCM ptr; | |
702551e6 | 216 | SCM cell_type; |
c7743d02 HWN |
217 | |
218 | ptr = p; | |
219 | scm_mark_dependencies_again: | |
76da80e7 | 220 | |
c7743d02 HWN |
221 | cell_type = SCM_GC_CELL_TYPE (ptr); |
222 | switch (SCM_ITAG7 (cell_type)) | |
223 | { | |
224 | case scm_tcs_cons_nimcar: | |
225 | if (SCM_IMP (SCM_CDR (ptr))) | |
226 | { | |
227 | ptr = SCM_CAR (ptr); | |
228 | goto gc_mark_nimp; | |
229 | } | |
33138b05 HWN |
230 | |
231 | ||
c7743d02 HWN |
232 | scm_gc_mark (SCM_CAR (ptr)); |
233 | ptr = SCM_CDR (ptr); | |
234 | goto gc_mark_nimp; | |
235 | case scm_tcs_cons_imcar: | |
236 | ptr = SCM_CDR (ptr); | |
237 | goto gc_mark_loop; | |
238 | case scm_tc7_pws: | |
33138b05 | 239 | |
c7743d02 HWN |
240 | scm_gc_mark (SCM_SETTER (ptr)); |
241 | ptr = SCM_PROCEDURE (ptr); | |
242 | goto gc_mark_loop; | |
243 | case scm_tcs_struct: | |
244 | { | |
245 | /* XXX - use less explicit code. */ | |
246 | scm_t_bits word0 = SCM_CELL_WORD_0 (ptr) - scm_tc3_struct; | |
247 | scm_t_bits * vtable_data = (scm_t_bits *) word0; | |
248 | SCM layout = SCM_PACK (vtable_data [scm_vtable_index_layout]); | |
eb01cb64 MV |
249 | long len = scm_i_symbol_length (layout); |
250 | const char *fields_desc = scm_i_symbol_chars (layout); | |
251 | scm_t_bits *struct_data = (scm_t_bits *) SCM_STRUCT_DATA (ptr); | |
c7743d02 HWN |
252 | |
253 | if (vtable_data[scm_struct_i_flags] & SCM_STRUCTF_ENTITY) | |
254 | { | |
255 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_procedure])); | |
256 | scm_gc_mark (SCM_PACK (struct_data[scm_struct_i_setter])); | |
257 | } | |
258 | if (len) | |
259 | { | |
260 | long x; | |
261 | ||
262 | for (x = 0; x < len - 2; x += 2, ++struct_data) | |
263 | if (fields_desc[x] == 'p') | |
264 | scm_gc_mark (SCM_PACK (*struct_data)); | |
265 | if (fields_desc[x] == 'p') | |
266 | { | |
267 | if (SCM_LAYOUT_TAILP (fields_desc[x + 1])) | |
268 | for (x = *struct_data++; x; --x, ++struct_data) | |
269 | scm_gc_mark (SCM_PACK (*struct_data)); | |
270 | else | |
271 | scm_gc_mark (SCM_PACK (*struct_data)); | |
272 | } | |
273 | } | |
274 | /* mark vtable */ | |
275 | ptr = SCM_PACK (vtable_data [scm_vtable_index_vtable]); | |
276 | goto gc_mark_loop; | |
277 | } | |
278 | break; | |
279 | case scm_tcs_closures: | |
280 | if (SCM_IMP (SCM_ENV (ptr))) | |
281 | { | |
282 | ptr = SCM_CLOSCAR (ptr); | |
283 | goto gc_mark_nimp; | |
284 | } | |
285 | scm_gc_mark (SCM_CLOSCAR (ptr)); | |
286 | ptr = SCM_ENV (ptr); | |
287 | goto gc_mark_nimp; | |
288 | case scm_tc7_vector: | |
4057a3e0 | 289 | i = SCM_SIMPLE_VECTOR_LENGTH (ptr); |
c7743d02 HWN |
290 | if (i == 0) |
291 | break; | |
292 | while (--i > 0) | |
33138b05 | 293 | { |
4057a3e0 MV |
294 | SCM elt = SCM_SIMPLE_VECTOR_REF (ptr, i); |
295 | if (SCM_NIMP (elt)) | |
296 | scm_gc_mark (elt); | |
33138b05 | 297 | } |
4057a3e0 | 298 | ptr = SCM_SIMPLE_VECTOR_REF (ptr, 0); |
c7743d02 | 299 | goto gc_mark_loop; |
eb01cb64 | 300 | |
c7743d02 | 301 | case scm_tc7_string: |
eb01cb64 MV |
302 | ptr = scm_i_string_mark (ptr); |
303 | goto gc_mark_loop; | |
304 | case scm_tc7_stringbuf: | |
305 | ptr = scm_i_stringbuf_mark (ptr); | |
306 | goto gc_mark_loop; | |
c7743d02 | 307 | |
534c55a9 | 308 | case scm_tc7_number: |
f92e85f7 MV |
309 | if (SCM_TYP16 (ptr) == scm_tc16_fraction) |
310 | { | |
311 | scm_gc_mark (SCM_CELL_OBJECT_1 (ptr)); | |
312 | ptr = SCM_CELL_OBJECT_2 (ptr); | |
313 | goto gc_mark_loop; | |
314 | } | |
534c55a9 DH |
315 | break; |
316 | ||
c7743d02 | 317 | case scm_tc7_wvect: |
06c1d900 | 318 | scm_i_mark_weak_vector (ptr); |
c7743d02 HWN |
319 | break; |
320 | ||
321 | case scm_tc7_symbol: | |
eb01cb64 | 322 | ptr = scm_i_symbol_mark (ptr); |
c7743d02 HWN |
323 | goto gc_mark_loop; |
324 | case scm_tc7_variable: | |
325 | ptr = SCM_CELL_OBJECT_1 (ptr); | |
326 | goto gc_mark_loop; | |
327 | case scm_tcs_subrs: | |
325226da AW |
328 | if (SCM_CELL_WORD_2 (ptr) && *(SCM*)SCM_CELL_WORD_2 (ptr)) |
329 | /* the generic associated with this primitive */ | |
330 | scm_gc_mark (*(SCM*)SCM_CELL_WORD_2 (ptr)); | |
331 | if (SCM_NIMP (((SCM*)SCM_CELL_WORD_3 (ptr))[1])) | |
332 | scm_gc_mark (((SCM*)SCM_CELL_WORD_3 (ptr))[1]); /* props */ | |
333 | ptr = ((SCM*)SCM_CELL_WORD_3 (ptr))[0]; /* name */ | |
334 | goto gc_mark_loop; | |
c7743d02 HWN |
335 | case scm_tc7_port: |
336 | i = SCM_PTOBNUM (ptr); | |
337 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
338 | if (!(i < scm_numptob)) | |
be3ff021 HWN |
339 | { |
340 | fprintf (stderr, "undefined port type"); | |
1f584400 | 341 | abort (); |
be3ff021 | 342 | } |
c7743d02 | 343 | #endif |
1f584400 | 344 | if (SCM_PTAB_ENTRY (ptr)) |
c7743d02 HWN |
345 | scm_gc_mark (SCM_FILENAME (ptr)); |
346 | if (scm_ptobs[i].mark) | |
347 | { | |
348 | ptr = (scm_ptobs[i].mark) (ptr); | |
349 | goto gc_mark_loop; | |
350 | } | |
351 | else | |
352 | return; | |
353 | break; | |
354 | case scm_tc7_smob: | |
355 | switch (SCM_TYP16 (ptr)) | |
356 | { /* should be faster than going through scm_smobs */ | |
357 | case scm_tc_free_cell: | |
358 | /* We have detected a free cell. This can happen if non-object data | |
359 | * on the C stack points into guile's heap and is scanned during | |
360 | * conservative marking. */ | |
361 | break; | |
c7743d02 HWN |
362 | default: |
363 | i = SCM_SMOBNUM (ptr); | |
364 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
365 | if (!(i < scm_numsmob)) | |
be3ff021 HWN |
366 | { |
367 | fprintf (stderr, "undefined smob type"); | |
1f584400 | 368 | abort (); |
be3ff021 | 369 | } |
c7743d02 HWN |
370 | #endif |
371 | if (scm_smobs[i].mark) | |
372 | { | |
373 | ptr = (scm_smobs[i].mark) (ptr); | |
374 | goto gc_mark_loop; | |
375 | } | |
376 | else | |
377 | return; | |
378 | } | |
379 | break; | |
380 | default: | |
be3ff021 | 381 | fprintf (stderr, "unknown type"); |
1f584400 | 382 | abort (); |
c7743d02 HWN |
383 | } |
384 | ||
385 | /* | |
386 | If we got here, then exhausted recursion options for PTR. we | |
387 | return (careful not to mark PTR, it might be the argument that we | |
388 | were called with.) | |
389 | */ | |
390 | return ; | |
06c1d900 MV |
391 | |
392 | gc_mark_loop: | |
c7743d02 HWN |
393 | if (SCM_IMP (ptr)) |
394 | return; | |
395 | ||
396 | gc_mark_nimp: | |
397 | { | |
398 | int valid_cell = CELL_P (ptr); | |
399 | ||
400 | ||
401 | #if (SCM_DEBUG_CELL_ACCESSES == 1) | |
402 | if (scm_debug_cell_accesses_p) | |
403 | { | |
404 | /* We are in debug mode. Check the ptr exhaustively. */ | |
405 | ||
40945e5e | 406 | valid_cell = valid_cell && scm_in_heap_p (ptr); |
c7743d02 HWN |
407 | } |
408 | ||
409 | #endif | |
410 | if (!valid_cell) | |
be3ff021 HWN |
411 | { |
412 | fprintf (stderr, "rogue pointer in heap"); | |
1f584400 | 413 | abort (); |
be3ff021 | 414 | } |
c7743d02 | 415 | } |
eab1b259 | 416 | |
82ae1b8e | 417 | if (SCM_GC_MARK_P (ptr)) |
76da80e7 | 418 | return; |
a54a94b3 | 419 | |
76da80e7 | 420 | SCM_SET_GC_MARK (ptr); |
eab1b259 | 421 | |
76da80e7 | 422 | goto scm_mark_dependencies_again; |
c7743d02 HWN |
423 | |
424 | } | |
425 | #undef FUNC_NAME | |
426 | ||
427 | ||
c7743d02 HWN |
428 | /* Mark a region conservatively */ |
429 | void | |
430 | scm_mark_locations (SCM_STACKITEM x[], unsigned long n) | |
431 | { | |
432 | unsigned long m; | |
433 | ||
434 | for (m = 0; m < n; ++m) | |
435 | { | |
436 | SCM obj = * (SCM *) &x[m]; | |
437 | long int segment = scm_i_find_heap_segment_containing_object (obj); | |
438 | if (segment >= 0) | |
439 | scm_gc_mark (obj); | |
440 | } | |
441 | } | |
442 | ||
443 | ||
444 | /* The function scm_in_heap_p determines whether an SCM value can be regarded as a | |
445 | * pointer to a cell on the heap. | |
446 | */ | |
447 | int | |
448 | scm_in_heap_p (SCM value) | |
449 | { | |
450 | long int segment = scm_i_find_heap_segment_containing_object (value); | |
451 | return (segment >= 0); | |
452 | } | |
453 | ||
454 | ||
455 | #if SCM_ENABLE_DEPRECATED == 1 | |
456 | ||
457 | /* If an allocated cell is detected during garbage collection, this | |
458 | * means that some code has just obtained the object but was preempted | |
459 | * before the initialization of the object was completed. This meanst | |
460 | * that some entries of the allocated cell may already contain SCM | |
461 | * objects. Therefore, allocated cells are scanned conservatively. | |
462 | */ | |
463 | ||
464 | scm_t_bits scm_tc16_allocated; | |
465 | ||
466 | static SCM | |
467 | allocated_mark (SCM cell) | |
468 | { | |
469 | unsigned long int cell_segment = scm_i_find_heap_segment_containing_object (cell); | |
470 | unsigned int span = scm_i_heap_segment_table[cell_segment]->span; | |
471 | unsigned int i; | |
472 | ||
473 | for (i = 1; i != span * 2; ++i) | |
474 | { | |
475 | SCM obj = SCM_CELL_OBJECT (cell, i); | |
476 | long int obj_segment = scm_i_find_heap_segment_containing_object (obj); | |
477 | if (obj_segment >= 0) | |
478 | scm_gc_mark (obj); | |
479 | } | |
480 | return SCM_BOOL_F; | |
481 | } | |
482 | ||
483 | SCM | |
484 | scm_deprecated_newcell (void) | |
485 | { | |
486 | scm_c_issue_deprecation_warning | |
487 | ("SCM_NEWCELL is deprecated. Use `scm_cell' instead.\n"); | |
488 | ||
489 | return scm_cell (scm_tc16_allocated, 0); | |
490 | } | |
491 | ||
492 | SCM | |
493 | scm_deprecated_newcell2 (void) | |
494 | { | |
495 | scm_c_issue_deprecation_warning | |
496 | ("SCM_NEWCELL2 is deprecated. Use `scm_double_cell' instead.\n"); | |
497 | ||
498 | return scm_double_cell (scm_tc16_allocated, 0, 0, 0); | |
499 | } | |
500 | ||
501 | #endif /* SCM_ENABLE_DEPRECATED == 1 */ | |
502 | ||
503 | ||
504 | void | |
1f584400 | 505 | scm_gc_init_mark (void) |
c7743d02 HWN |
506 | { |
507 | #if SCM_ENABLE_DEPRECATED == 1 | |
508 | scm_tc16_allocated = scm_make_smob_type ("allocated cell", 0); | |
509 | scm_set_smob_mark (scm_tc16_allocated, allocated_mark); | |
510 | #endif | |
511 | } | |
512 |