2 * GENerational Conservative Garbage Collector for SBCL x86
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 * For a review of garbage collection techniques (e.g. generational
18 * GC) and terminology (e.g. "scavenging") see Paul R. Wilson,
19 * "Uniprocessor Garbage Collection Techniques". As of 20000618, this
20 * had been accepted for _ACM Computing Surveys_ and was available
21 * as a PostScript preprint through
22 * <http://www.cs.utexas.edu/users/oops/papers.html>
24 * <ftp://ftp.cs.utexas.edu/pub/garbage/bigsurv.ps>.
36 #include "interrupt.h"
41 #include "gc-internal.h"
43 #include "genesis/vector.h"
44 #include "genesis/weak-pointer.h"
45 #include "genesis/simple-fun.h"
47 /* assembly language stub that executes trap_PendingInterrupt */
48 void do_pending_interrupt(void);
50 /* forward declarations */
51 int gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed);
52 void gc_set_region_empty(struct alloc_region *region);
53 void gc_alloc_update_all_page_tables(void);
54 static void gencgc_pickup_dynamic(void);
55 boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
62 /* the number of actual generations. (The number of 'struct
63 * generation' objects is one more than this, because one object
64 * serves as scratch when GC'ing.) */
65 #define NUM_GENERATIONS 6
67 /* Should we use page protection to help avoid the scavenging of pages
68 * that don't have pointers to younger generations? */
69 boolean enable_page_protection = 1;
71 /* the minimum size (in bytes) for a large object*/
72 unsigned large_object_size = 4 * PAGE_BYTES;
81 /* the verbosity level. All non-error messages are disabled at level 0;
82 * and only a few rare messages are printed at level 1. */
83 unsigned gencgc_verbose = (QSHOW ? 1 : 0);
85 /* FIXME: At some point enable the various error-checking things below
86 * and see what they say. */
88 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
89 * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
90 int verify_gens = NUM_GENERATIONS;
92 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
93 boolean pre_verify_gen_0 = 0;
95 /* Should we check for bad pointers after gc_free_heap is called
96 * from Lisp PURIFY? */
97 boolean verify_after_free_heap = 0;
99 /* Should we print a note when code objects are found in the dynamic space
100 * during a heap verify? */
101 boolean verify_dynamic_code_check = 0;
103 /* Should we check code objects for fixup errors after they are transported? */
104 boolean check_code_fixups = 0;
106 /* Should we check that newly allocated regions are zero filled? */
107 boolean gencgc_zero_check = 0;
109 /* Should we check that the free space is zero filled? */
110 boolean gencgc_enable_verify_zero_fill = 0;
112 /* Should we check that free pages are zero filled during gc_free_heap
113 * called after Lisp PURIFY? */
114 boolean gencgc_zero_check_during_free_heap = 0;
117 * GC structures and variables
120 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
121 unsigned long bytes_allocated = 0;
122 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
123 unsigned long auto_gc_trigger = 0;
125 /* the source and destination generations. These are set before a GC starts
131 /* An array of page structures is statically allocated.
132 * This helps quickly map between an address its page structure.
133 * NUM_PAGES is set from the size of the dynamic space. */
134 struct page page_table[NUM_PAGES];
136 /* To map addresses to page structures the address of the first page
138 static void *heap_base = NULL;
141 /* Calculate the start address for the given page number. */
143 page_address(int page_num)
145 return (heap_base + (page_num * PAGE_BYTES));
148 /* Find the page index within the page_table for the given
149 * address. Return -1 on failure. */
151 find_page_index(void *addr)
153 int index = addr-heap_base;
156 index = ((unsigned int)index)/PAGE_BYTES;
157 if (index < NUM_PAGES)
164 /* a structure to hold the state of a generation */
167 /* the first page that gc_alloc() checks on its next call */
168 int alloc_start_page;
170 /* the first page that gc_alloc_unboxed() checks on its next call */
171 int alloc_unboxed_start_page;
173 /* the first page that gc_alloc_large (boxed) considers on its next
174 * call. (Although it always allocates after the boxed_region.) */
175 int alloc_large_start_page;
177 /* the first page that gc_alloc_large (unboxed) considers on its
178 * next call. (Although it always allocates after the
179 * current_unboxed_region.) */
180 int alloc_large_unboxed_start_page;
182 /* the bytes allocated to this generation */
185 /* the number of bytes at which to trigger a GC */
188 /* to calculate a new level for gc_trigger */
189 int bytes_consed_between_gc;
191 /* the number of GCs since the last raise */
194 /* the average age after which a GC will raise objects to the
198 /* the cumulative sum of the bytes allocated to this generation. It is
199 * cleared after a GC on this generations, and update before new
200 * objects are added from a GC of a younger generation. Dividing by
201 * the bytes_allocated will give the average age of the memory in
202 * this generation since its last GC. */
203 int cum_sum_bytes_allocated;
205 /* a minimum average memory age before a GC will occur helps
206 * prevent a GC when a large number of new live objects have been
207 * added, in which case a GC could be a waste of time */
208 double min_av_mem_age;
210 /* the number of actual generations. (The number of 'struct
211 * generation' objects is one more than this, because one object
212 * serves as scratch when GC'ing.) */
213 #define NUM_GENERATIONS 6
215 /* an array of generation structures. There needs to be one more
216 * generation structure than actual generations as the oldest
217 * generation is temporarily raised then lowered. */
218 struct generation generations[NUM_GENERATIONS+1];
220 /* the oldest generation that is will currently be GCed by default.
221 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
223 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
225 * Setting this to 0 effectively disables the generational nature of
226 * the GC. In some applications generational GC may not be useful
227 * because there are no long-lived objects.
229 * An intermediate value could be handy after moving long-lived data
230 * into an older generation so an unnecessary GC of this long-lived
231 * data can be avoided. */
232 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
234 /* The maximum free page in the heap is maintained and used to update
235 * ALLOCATION_POINTER which is used by the room function to limit its
236 * search of the heap. XX Gencgc obviously needs to be better
237 * integrated with the Lisp code. */
238 static int last_free_page;
240 /* This lock is to prevent multiple threads from simultaneously
241 * allocating new regions which overlap each other. Note that the
242 * majority of GC is single-threaded, but alloc() may be called from
243 * >1 thread at a time and must be thread-safe. This lock must be
244 * seized before all accesses to generations[] or to parts of
245 * page_table[] that other threads may want to see */
247 static lispobj free_pages_lock=0;
251 * miscellaneous heap functions
254 /* Count the number of pages which are write-protected within the
255 * given generation. */
257 count_write_protect_generation_pages(int generation)
262 for (i = 0; i < last_free_page; i++)
263 if ((page_table[i].allocated != FREE_PAGE_FLAG)
264 && (page_table[i].gen == generation)
265 && (page_table[i].write_protected == 1))
270 /* Count the number of pages within the given generation. */
272 count_generation_pages(int generation)
277 for (i = 0; i < last_free_page; i++)
278 if ((page_table[i].allocated != 0)
279 && (page_table[i].gen == generation))
286 count_dont_move_pages(void)
290 for (i = 0; i < last_free_page; i++) {
291 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
299 /* Work through the pages and add up the number of bytes used for the
300 * given generation. */
302 count_generation_bytes_allocated (int gen)
306 for (i = 0; i < last_free_page; i++) {
307 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
308 result += page_table[i].bytes_used;
313 /* Return the average age of the memory in a generation. */
315 gen_av_mem_age(int gen)
317 if (generations[gen].bytes_allocated == 0)
321 ((double)generations[gen].cum_sum_bytes_allocated)
322 / ((double)generations[gen].bytes_allocated);
325 void fpu_save(int *); /* defined in x86-assem.S */
326 void fpu_restore(int *); /* defined in x86-assem.S */
327 /* The verbose argument controls how much to print: 0 for normal
328 * level of detail; 1 for debugging. */
330 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
335 /* This code uses the FP instructions which may be set up for Lisp
336 * so they need to be saved and reset for C. */
339 /* number of generations to print */
341 gens = NUM_GENERATIONS+1;
343 gens = NUM_GENERATIONS;
345 /* Print the heap stats. */
347 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
349 for (i = 0; i < gens; i++) {
353 int large_boxed_cnt = 0;
354 int large_unboxed_cnt = 0;
357 for (j = 0; j < last_free_page; j++)
358 if (page_table[j].gen == i) {
360 /* Count the number of boxed pages within the given
362 if (page_table[j].allocated & BOXED_PAGE_FLAG) {
363 if (page_table[j].large_object)
368 if(page_table[j].dont_move) pinned_cnt++;
369 /* Count the number of unboxed pages within the given
371 if (page_table[j].allocated & UNBOXED_PAGE_FLAG) {
372 if (page_table[j].large_object)
379 gc_assert(generations[i].bytes_allocated
380 == count_generation_bytes_allocated(i));
382 " %1d: %5d %5d %5d %5d %5d %8d %5d %8d %4d %3d %7.4f\n",
384 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
386 generations[i].bytes_allocated,
387 (count_generation_pages(i)*PAGE_BYTES
388 - generations[i].bytes_allocated),
389 generations[i].gc_trigger,
390 count_write_protect_generation_pages(i),
391 generations[i].num_gc,
394 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
396 fpu_restore(fpu_state);
400 * allocation routines
404 * To support quick and inline allocation, regions of memory can be
405 * allocated and then allocated from with just a free pointer and a
406 * check against an end address.
408 * Since objects can be allocated to spaces with different properties
409 * e.g. boxed/unboxed, generation, ages; there may need to be many
410 * allocation regions.
412 * Each allocation region may be start within a partly used page. Many
413 * features of memory use are noted on a page wise basis, e.g. the
414 * generation; so if a region starts within an existing allocated page
415 * it must be consistent with this page.
417 * During the scavenging of the newspace, objects will be transported
418 * into an allocation region, and pointers updated to point to this
419 * allocation region. It is possible that these pointers will be
420 * scavenged again before the allocation region is closed, e.g. due to
421 * trans_list which jumps all over the place to cleanup the list. It
422 * is important to be able to determine properties of all objects
423 * pointed to when scavenging, e.g to detect pointers to the oldspace.
424 * Thus it's important that the allocation regions have the correct
425 * properties set when allocated, and not just set when closed. The
426 * region allocation routines return regions with the specified
427 * properties, and grab all the pages, setting their properties
428 * appropriately, except that the amount used is not known.
430 * These regions are used to support quicker allocation using just a
431 * free pointer. The actual space used by the region is not reflected
432 * in the pages tables until it is closed. It can't be scavenged until
435 * When finished with the region it should be closed, which will
436 * update the page tables for the actual space used returning unused
437 * space. Further it may be noted in the new regions which is
438 * necessary when scavenging the newspace.
440 * Large objects may be allocated directly without an allocation
441 * region, the page tables are updated immediately.
443 * Unboxed objects don't contain pointers to other objects and so
444 * don't need scavenging. Further they can't contain pointers to
445 * younger generations so WP is not needed. By allocating pages to
446 * unboxed objects the whole page never needs scavenging or
447 * write-protecting. */
449 /* We are only using two regions at present. Both are for the current
450 * newspace generation. */
451 struct alloc_region boxed_region;
452 struct alloc_region unboxed_region;
454 /* The generation currently being allocated to. */
455 static int gc_alloc_generation;
457 /* Find a new region with room for at least the given number of bytes.
459 * It starts looking at the current generation's alloc_start_page. So
460 * may pick up from the previous region if there is enough space. This
461 * keeps the allocation contiguous when scavenging the newspace.
463 * The alloc_region should have been closed by a call to
464 * gc_alloc_update_page_tables(), and will thus be in an empty state.
466 * To assist the scavenging functions write-protected pages are not
467 * used. Free pages should not be write-protected.
469 * It is critical to the conservative GC that the start of regions be
470 * known. To help achieve this only small regions are allocated at a
473 * During scavenging, pointers may be found to within the current
474 * region and the page generation must be set so that pointers to the
475 * from space can be recognized. Therefore the generation of pages in
476 * the region are set to gc_alloc_generation. To prevent another
477 * allocation call using the same pages, all the pages in the region
478 * are allocated, although they will initially be empty.
481 gc_alloc_new_region(int nbytes, int unboxed, struct alloc_region *alloc_region)
490 "/alloc_new_region for %d bytes from gen %d\n",
491 nbytes, gc_alloc_generation));
494 /* Check that the region is in a reset state. */
495 gc_assert((alloc_region->first_page == 0)
496 && (alloc_region->last_page == -1)
497 && (alloc_region->free_pointer == alloc_region->end_addr));
498 get_spinlock(&free_pages_lock,(int) alloc_region);
501 generations[gc_alloc_generation].alloc_unboxed_start_page;
504 generations[gc_alloc_generation].alloc_start_page;
506 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
507 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
508 + PAGE_BYTES*(last_page-first_page);
510 /* Set up the alloc_region. */
511 alloc_region->first_page = first_page;
512 alloc_region->last_page = last_page;
513 alloc_region->start_addr = page_table[first_page].bytes_used
514 + page_address(first_page);
515 alloc_region->free_pointer = alloc_region->start_addr;
516 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
518 /* Set up the pages. */
520 /* The first page may have already been in use. */
521 if (page_table[first_page].bytes_used == 0) {
523 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
525 page_table[first_page].allocated = BOXED_PAGE_FLAG;
526 page_table[first_page].gen = gc_alloc_generation;
527 page_table[first_page].large_object = 0;
528 page_table[first_page].first_object_offset = 0;
532 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
534 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
535 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
537 gc_assert(page_table[first_page].gen == gc_alloc_generation);
538 gc_assert(page_table[first_page].large_object == 0);
540 for (i = first_page+1; i <= last_page; i++) {
542 page_table[i].allocated = UNBOXED_PAGE_FLAG;
544 page_table[i].allocated = BOXED_PAGE_FLAG;
545 page_table[i].gen = gc_alloc_generation;
546 page_table[i].large_object = 0;
547 /* This may not be necessary for unboxed regions (think it was
549 page_table[i].first_object_offset =
550 alloc_region->start_addr - page_address(i);
551 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
553 /* Bump up last_free_page. */
554 if (last_page+1 > last_free_page) {
555 last_free_page = last_page+1;
556 SetSymbolValue(ALLOCATION_POINTER,
557 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
560 release_spinlock(&free_pages_lock);
562 /* we can do this after releasing free_pages_lock */
563 if (gencgc_zero_check) {
565 for (p = (int *)alloc_region->start_addr;
566 p < (int *)alloc_region->end_addr; p++) {
568 /* KLUDGE: It would be nice to use %lx and explicit casts
569 * (long) in code like this, so that it is less likely to
570 * break randomly when running on a machine with different
571 * word sizes. -- WHN 19991129 */
572 lose("The new region at %x is not zero.", p);
579 /* If the record_new_objects flag is 2 then all new regions created
582 * If it's 1 then then it is only recorded if the first page of the
583 * current region is <= new_areas_ignore_page. This helps avoid
584 * unnecessary recording when doing full scavenge pass.
586 * The new_object structure holds the page, byte offset, and size of
587 * new regions of objects. Each new area is placed in the array of
588 * these structures pointer to by new_areas. new_areas_index holds the
589 * offset into new_areas.
591 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
592 * later code must detect this and handle it, probably by doing a full
593 * scavenge of a generation. */
594 #define NUM_NEW_AREAS 512
595 static int record_new_objects = 0;
596 static int new_areas_ignore_page;
602 static struct new_area (*new_areas)[];
603 static int new_areas_index;
606 /* Add a new area to new_areas. */
608 add_new_area(int first_page, int offset, int size)
610 unsigned new_area_start,c;
613 /* Ignore if full. */
614 if (new_areas_index >= NUM_NEW_AREAS)
617 switch (record_new_objects) {
621 if (first_page > new_areas_ignore_page)
630 new_area_start = PAGE_BYTES*first_page + offset;
632 /* Search backwards for a prior area that this follows from. If
633 found this will save adding a new area. */
634 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
636 PAGE_BYTES*((*new_areas)[i].page)
637 + (*new_areas)[i].offset
638 + (*new_areas)[i].size;
640 "/add_new_area S1 %d %d %d %d\n",
641 i, c, new_area_start, area_end));*/
642 if (new_area_start == area_end) {
644 "/adding to [%d] %d %d %d with %d %d %d:\n",
646 (*new_areas)[i].page,
647 (*new_areas)[i].offset,
648 (*new_areas)[i].size,
652 (*new_areas)[i].size += size;
657 (*new_areas)[new_areas_index].page = first_page;
658 (*new_areas)[new_areas_index].offset = offset;
659 (*new_areas)[new_areas_index].size = size;
661 "/new_area %d page %d offset %d size %d\n",
662 new_areas_index, first_page, offset, size));*/
665 /* Note the max new_areas used. */
666 if (new_areas_index > max_new_areas)
667 max_new_areas = new_areas_index;
670 /* Update the tables for the alloc_region. The region may be added to
673 * When done the alloc_region is set up so that the next quick alloc
674 * will fail safely and thus a new region will be allocated. Further
675 * it is safe to try to re-update the page table of this reset
678 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
684 int orig_first_page_bytes_used;
689 first_page = alloc_region->first_page;
691 /* Catch an unused alloc_region. */
692 if ((first_page == 0) && (alloc_region->last_page == -1))
695 next_page = first_page+1;
697 get_spinlock(&free_pages_lock,(int) alloc_region);
698 if (alloc_region->free_pointer != alloc_region->start_addr) {
699 /* some bytes were allocated in the region */
700 orig_first_page_bytes_used = page_table[first_page].bytes_used;
702 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
704 /* All the pages used need to be updated */
706 /* Update the first page. */
708 /* If the page was free then set up the gen, and
709 * first_object_offset. */
710 if (page_table[first_page].bytes_used == 0)
711 gc_assert(page_table[first_page].first_object_offset == 0);
712 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
715 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
717 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
718 gc_assert(page_table[first_page].gen == gc_alloc_generation);
719 gc_assert(page_table[first_page].large_object == 0);
723 /* Calculate the number of bytes used in this page. This is not
724 * always the number of new bytes, unless it was free. */
726 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
727 bytes_used = PAGE_BYTES;
730 page_table[first_page].bytes_used = bytes_used;
731 byte_cnt += bytes_used;
734 /* All the rest of the pages should be free. We need to set their
735 * first_object_offset pointer to the start of the region, and set
738 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
740 gc_assert(page_table[next_page].allocated==UNBOXED_PAGE_FLAG);
742 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
743 gc_assert(page_table[next_page].bytes_used == 0);
744 gc_assert(page_table[next_page].gen == gc_alloc_generation);
745 gc_assert(page_table[next_page].large_object == 0);
747 gc_assert(page_table[next_page].first_object_offset ==
748 alloc_region->start_addr - page_address(next_page));
750 /* Calculate the number of bytes used in this page. */
752 if ((bytes_used = (alloc_region->free_pointer
753 - page_address(next_page)))>PAGE_BYTES) {
754 bytes_used = PAGE_BYTES;
757 page_table[next_page].bytes_used = bytes_used;
758 byte_cnt += bytes_used;
763 region_size = alloc_region->free_pointer - alloc_region->start_addr;
764 bytes_allocated += region_size;
765 generations[gc_alloc_generation].bytes_allocated += region_size;
767 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
769 /* Set the generations alloc restart page to the last page of
772 generations[gc_alloc_generation].alloc_unboxed_start_page =
775 generations[gc_alloc_generation].alloc_start_page = next_page-1;
777 /* Add the region to the new_areas if requested. */
779 add_new_area(first_page,orig_first_page_bytes_used, region_size);
783 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
785 gc_alloc_generation));
788 /* There are no bytes allocated. Unallocate the first_page if
789 * there are 0 bytes_used. */
790 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
791 if (page_table[first_page].bytes_used == 0)
792 page_table[first_page].allocated = FREE_PAGE_FLAG;
795 /* Unallocate any unused pages. */
796 while (next_page <= alloc_region->last_page) {
797 gc_assert(page_table[next_page].bytes_used == 0);
798 page_table[next_page].allocated = FREE_PAGE_FLAG;
801 release_spinlock(&free_pages_lock);
802 /* alloc_region is per-thread, we're ok to do this unlocked */
803 gc_set_region_empty(alloc_region);
806 static inline void *gc_quick_alloc(int nbytes);
808 /* Allocate a possibly large object. */
810 gc_alloc_large(int nbytes, int unboxed, struct alloc_region *alloc_region)
814 int orig_first_page_bytes_used;
820 get_spinlock(&free_pages_lock,(int) alloc_region);
824 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
826 first_page = generations[gc_alloc_generation].alloc_large_start_page;
828 if (first_page <= alloc_region->last_page) {
829 first_page = alloc_region->last_page+1;
832 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
834 gc_assert(first_page > alloc_region->last_page);
836 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
839 generations[gc_alloc_generation].alloc_large_start_page = last_page;
841 /* Set up the pages. */
842 orig_first_page_bytes_used = page_table[first_page].bytes_used;
844 /* If the first page was free then set up the gen, and
845 * first_object_offset. */
846 if (page_table[first_page].bytes_used == 0) {
848 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
850 page_table[first_page].allocated = BOXED_PAGE_FLAG;
851 page_table[first_page].gen = gc_alloc_generation;
852 page_table[first_page].first_object_offset = 0;
853 page_table[first_page].large_object = 1;
857 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
859 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
860 gc_assert(page_table[first_page].gen == gc_alloc_generation);
861 gc_assert(page_table[first_page].large_object == 1);
865 /* Calc. the number of bytes used in this page. This is not
866 * always the number of new bytes, unless it was free. */
868 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
869 bytes_used = PAGE_BYTES;
872 page_table[first_page].bytes_used = bytes_used;
873 byte_cnt += bytes_used;
875 next_page = first_page+1;
877 /* All the rest of the pages should be free. We need to set their
878 * first_object_offset pointer to the start of the region, and
879 * set the bytes_used. */
881 gc_assert(page_table[next_page].allocated == FREE_PAGE_FLAG);
882 gc_assert(page_table[next_page].bytes_used == 0);
884 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
886 page_table[next_page].allocated = BOXED_PAGE_FLAG;
887 page_table[next_page].gen = gc_alloc_generation;
888 page_table[next_page].large_object = 1;
890 page_table[next_page].first_object_offset =
891 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
893 /* Calculate the number of bytes used in this page. */
895 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
896 bytes_used = PAGE_BYTES;
899 page_table[next_page].bytes_used = bytes_used;
900 page_table[next_page].write_protected=0;
901 page_table[next_page].dont_move=0;
902 byte_cnt += bytes_used;
906 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
908 bytes_allocated += nbytes;
909 generations[gc_alloc_generation].bytes_allocated += nbytes;
911 /* Add the region to the new_areas if requested. */
913 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
915 /* Bump up last_free_page */
916 if (last_page+1 > last_free_page) {
917 last_free_page = last_page+1;
918 SetSymbolValue(ALLOCATION_POINTER,
919 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
921 release_spinlock(&free_pages_lock);
923 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
927 gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed)
932 int restart_page=*restart_page_ptr;
935 int large_p=(nbytes>=large_object_size);
936 gc_assert(free_pages_lock);
938 /* Search for a contiguous free space of at least nbytes. If it's
939 * a large object then align it on a page boundary by searching
940 * for a free page. */
943 first_page = restart_page;
945 while ((first_page < NUM_PAGES)
946 && (page_table[first_page].allocated != FREE_PAGE_FLAG))
949 while (first_page < NUM_PAGES) {
950 if(page_table[first_page].allocated == FREE_PAGE_FLAG)
952 if((page_table[first_page].allocated ==
953 (unboxed ? UNBOXED_PAGE_FLAG : BOXED_PAGE_FLAG)) &&
954 (page_table[first_page].large_object == 0) &&
955 (page_table[first_page].gen == gc_alloc_generation) &&
956 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
957 (page_table[first_page].write_protected == 0) &&
958 (page_table[first_page].dont_move == 0)) {
964 if (first_page >= NUM_PAGES) {
966 "Argh! gc_find_free_space failed (first_page), nbytes=%d.\n",
968 print_generation_stats(1);
972 gc_assert(page_table[first_page].write_protected == 0);
974 last_page = first_page;
975 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
977 while (((bytes_found < nbytes)
978 || (!large_p && (num_pages < 2)))
979 && (last_page < (NUM_PAGES-1))
980 && (page_table[last_page+1].allocated == FREE_PAGE_FLAG)) {
983 bytes_found += PAGE_BYTES;
984 gc_assert(page_table[last_page].write_protected == 0);
987 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
988 + PAGE_BYTES*(last_page-first_page);
990 gc_assert(bytes_found == region_size);
991 restart_page = last_page + 1;
992 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
994 /* Check for a failure */
995 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
997 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%d.\n",
999 print_generation_stats(1);
1002 *restart_page_ptr=first_page;
1006 /* Allocate bytes. All the rest of the special-purpose allocation
1007 * functions will eventually call this */
1010 gc_alloc_with_region(int nbytes,int unboxed_p, struct alloc_region *my_region,
1013 void *new_free_pointer;
1015 if(nbytes>=large_object_size)
1016 return gc_alloc_large(nbytes,unboxed_p,my_region);
1018 /* Check whether there is room in the current alloc region. */
1019 new_free_pointer = my_region->free_pointer + nbytes;
1021 if (new_free_pointer <= my_region->end_addr) {
1022 /* If so then allocate from the current alloc region. */
1023 void *new_obj = my_region->free_pointer;
1024 my_region->free_pointer = new_free_pointer;
1026 /* Unless a `quick' alloc was requested, check whether the
1027 alloc region is almost empty. */
1029 (my_region->end_addr - my_region->free_pointer) <= 32) {
1030 /* If so, finished with the current region. */
1031 gc_alloc_update_page_tables(unboxed_p, my_region);
1032 /* Set up a new region. */
1033 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1036 return((void *)new_obj);
1039 /* Else not enough free space in the current region: retry with a
1042 gc_alloc_update_page_tables(unboxed_p, my_region);
1043 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1044 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1047 /* these are only used during GC: all allocation from the mutator calls
1048 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1052 gc_general_alloc(int nbytes,int unboxed_p,int quick_p)
1054 struct alloc_region *my_region =
1055 unboxed_p ? &unboxed_region : &boxed_region;
1056 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1059 static inline void *
1060 gc_quick_alloc(int nbytes)
1062 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1065 static inline void *
1066 gc_quick_alloc_large(int nbytes)
1068 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1071 static inline void *
1072 gc_alloc_unboxed(int nbytes)
1074 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1077 static inline void *
1078 gc_quick_alloc_unboxed(int nbytes)
1080 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1083 static inline void *
1084 gc_quick_alloc_large_unboxed(int nbytes)
1086 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1090 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1093 extern int (*scavtab[256])(lispobj *where, lispobj object);
1094 extern lispobj (*transother[256])(lispobj object);
1095 extern int (*sizetab[256])(lispobj *where);
1097 /* Copy a large boxed object. If the object is in a large object
1098 * region then it is simply promoted, else it is copied. If it's large
1099 * enough then it's copied to a large object region.
1101 * Vectors may have shrunk. If the object is not copied the space
1102 * needs to be reclaimed, and the page_tables corrected. */
1104 copy_large_object(lispobj object, int nwords)
1110 gc_assert(is_lisp_pointer(object));
1111 gc_assert(from_space_p(object));
1112 gc_assert((nwords & 0x01) == 0);
1115 /* Check whether it's in a large object region. */
1116 first_page = find_page_index((void *)object);
1117 gc_assert(first_page >= 0);
1119 if (page_table[first_page].large_object) {
1121 /* Promote the object. */
1123 int remaining_bytes;
1128 /* Note: Any page write-protection must be removed, else a
1129 * later scavenge_newspace may incorrectly not scavenge these
1130 * pages. This would not be necessary if they are added to the
1131 * new areas, but let's do it for them all (they'll probably
1132 * be written anyway?). */
1134 gc_assert(page_table[first_page].first_object_offset == 0);
1136 next_page = first_page;
1137 remaining_bytes = nwords*4;
1138 while (remaining_bytes > PAGE_BYTES) {
1139 gc_assert(page_table[next_page].gen == from_space);
1140 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1141 gc_assert(page_table[next_page].large_object);
1142 gc_assert(page_table[next_page].first_object_offset==
1143 -PAGE_BYTES*(next_page-first_page));
1144 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1146 page_table[next_page].gen = new_space;
1148 /* Remove any write-protection. We should be able to rely
1149 * on the write-protect flag to avoid redundant calls. */
1150 if (page_table[next_page].write_protected) {
1151 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1152 page_table[next_page].write_protected = 0;
1154 remaining_bytes -= PAGE_BYTES;
1158 /* Now only one page remains, but the object may have shrunk
1159 * so there may be more unused pages which will be freed. */
1161 /* The object may have shrunk but shouldn't have grown. */
1162 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1164 page_table[next_page].gen = new_space;
1165 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1167 /* Adjust the bytes_used. */
1168 old_bytes_used = page_table[next_page].bytes_used;
1169 page_table[next_page].bytes_used = remaining_bytes;
1171 bytes_freed = old_bytes_used - remaining_bytes;
1173 /* Free any remaining pages; needs care. */
1175 while ((old_bytes_used == PAGE_BYTES) &&
1176 (page_table[next_page].gen == from_space) &&
1177 (page_table[next_page].allocated == BOXED_PAGE_FLAG) &&
1178 page_table[next_page].large_object &&
1179 (page_table[next_page].first_object_offset ==
1180 -(next_page - first_page)*PAGE_BYTES)) {
1181 /* Checks out OK, free the page. Don't need to bother zeroing
1182 * pages as this should have been done before shrinking the
1183 * object. These pages shouldn't be write-protected as they
1184 * should be zero filled. */
1185 gc_assert(page_table[next_page].write_protected == 0);
1187 old_bytes_used = page_table[next_page].bytes_used;
1188 page_table[next_page].allocated = FREE_PAGE_FLAG;
1189 page_table[next_page].bytes_used = 0;
1190 bytes_freed += old_bytes_used;
1194 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1195 generations[new_space].bytes_allocated += 4*nwords;
1196 bytes_allocated -= bytes_freed;
1198 /* Add the region to the new_areas if requested. */
1199 add_new_area(first_page,0,nwords*4);
1203 /* Get tag of object. */
1204 tag = lowtag_of(object);
1206 /* Allocate space. */
1207 new = gc_quick_alloc_large(nwords*4);
1209 memcpy(new,native_pointer(object),nwords*4);
1211 /* Return Lisp pointer of new object. */
1212 return ((lispobj) new) | tag;
1216 /* to copy unboxed objects */
1218 copy_unboxed_object(lispobj object, int nwords)
1223 gc_assert(is_lisp_pointer(object));
1224 gc_assert(from_space_p(object));
1225 gc_assert((nwords & 0x01) == 0);
1227 /* Get tag of object. */
1228 tag = lowtag_of(object);
1230 /* Allocate space. */
1231 new = gc_quick_alloc_unboxed(nwords*4);
1233 memcpy(new,native_pointer(object),nwords*4);
1235 /* Return Lisp pointer of new object. */
1236 return ((lispobj) new) | tag;
1239 /* to copy large unboxed objects
1241 * If the object is in a large object region then it is simply
1242 * promoted, else it is copied. If it's large enough then it's copied
1243 * to a large object region.
1245 * Bignums and vectors may have shrunk. If the object is not copied
1246 * the space needs to be reclaimed, and the page_tables corrected.
1248 * KLUDGE: There's a lot of cut-and-paste duplication between this
1249 * function and copy_large_object(..). -- WHN 20000619 */
1251 copy_large_unboxed_object(lispobj object, int nwords)
1255 lispobj *source, *dest;
1258 gc_assert(is_lisp_pointer(object));
1259 gc_assert(from_space_p(object));
1260 gc_assert((nwords & 0x01) == 0);
1262 if ((nwords > 1024*1024) && gencgc_verbose)
1263 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*4));
1265 /* Check whether it's a large object. */
1266 first_page = find_page_index((void *)object);
1267 gc_assert(first_page >= 0);
1269 if (page_table[first_page].large_object) {
1270 /* Promote the object. Note: Unboxed objects may have been
1271 * allocated to a BOXED region so it may be necessary to
1272 * change the region to UNBOXED. */
1273 int remaining_bytes;
1278 gc_assert(page_table[first_page].first_object_offset == 0);
1280 next_page = first_page;
1281 remaining_bytes = nwords*4;
1282 while (remaining_bytes > PAGE_BYTES) {
1283 gc_assert(page_table[next_page].gen == from_space);
1284 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1285 || (page_table[next_page].allocated == BOXED_PAGE_FLAG));
1286 gc_assert(page_table[next_page].large_object);
1287 gc_assert(page_table[next_page].first_object_offset==
1288 -PAGE_BYTES*(next_page-first_page));
1289 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1291 page_table[next_page].gen = new_space;
1292 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1293 remaining_bytes -= PAGE_BYTES;
1297 /* Now only one page remains, but the object may have shrunk so
1298 * there may be more unused pages which will be freed. */
1300 /* Object may have shrunk but shouldn't have grown - check. */
1301 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1303 page_table[next_page].gen = new_space;
1304 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1306 /* Adjust the bytes_used. */
1307 old_bytes_used = page_table[next_page].bytes_used;
1308 page_table[next_page].bytes_used = remaining_bytes;
1310 bytes_freed = old_bytes_used - remaining_bytes;
1312 /* Free any remaining pages; needs care. */
1314 while ((old_bytes_used == PAGE_BYTES) &&
1315 (page_table[next_page].gen == from_space) &&
1316 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1317 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
1318 page_table[next_page].large_object &&
1319 (page_table[next_page].first_object_offset ==
1320 -(next_page - first_page)*PAGE_BYTES)) {
1321 /* Checks out OK, free the page. Don't need to both zeroing
1322 * pages as this should have been done before shrinking the
1323 * object. These pages shouldn't be write-protected, even if
1324 * boxed they should be zero filled. */
1325 gc_assert(page_table[next_page].write_protected == 0);
1327 old_bytes_used = page_table[next_page].bytes_used;
1328 page_table[next_page].allocated = FREE_PAGE_FLAG;
1329 page_table[next_page].bytes_used = 0;
1330 bytes_freed += old_bytes_used;
1334 if ((bytes_freed > 0) && gencgc_verbose)
1336 "/copy_large_unboxed bytes_freed=%d\n",
1339 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1340 generations[new_space].bytes_allocated += 4*nwords;
1341 bytes_allocated -= bytes_freed;
1346 /* Get tag of object. */
1347 tag = lowtag_of(object);
1349 /* Allocate space. */
1350 new = gc_quick_alloc_large_unboxed(nwords*4);
1353 source = (lispobj *) native_pointer(object);
1355 /* Copy the object. */
1356 while (nwords > 0) {
1357 dest[0] = source[0];
1358 dest[1] = source[1];
1364 /* Return Lisp pointer of new object. */
1365 return ((lispobj) new) | tag;
1374 * code and code-related objects
1377 static lispobj trans_fun_header(lispobj object);
1378 static lispobj trans_boxed(lispobj object);
1381 /* Scan a x86 compiled code object, looking for possible fixups that
1382 * have been missed after a move.
1384 * Two types of fixups are needed:
1385 * 1. Absolute fixups to within the code object.
1386 * 2. Relative fixups to outside the code object.
1388 * Currently only absolute fixups to the constant vector, or to the
1389 * code area are checked. */
1391 sniff_code_object(struct code *code, unsigned displacement)
1393 int nheader_words, ncode_words, nwords;
1395 void *constants_start_addr, *constants_end_addr;
1396 void *code_start_addr, *code_end_addr;
1397 int fixup_found = 0;
1399 if (!check_code_fixups)
1402 ncode_words = fixnum_value(code->code_size);
1403 nheader_words = HeaderValue(*(lispobj *)code);
1404 nwords = ncode_words + nheader_words;
1406 constants_start_addr = (void *)code + 5*4;
1407 constants_end_addr = (void *)code + nheader_words*4;
1408 code_start_addr = (void *)code + nheader_words*4;
1409 code_end_addr = (void *)code + nwords*4;
1411 /* Work through the unboxed code. */
1412 for (p = code_start_addr; p < code_end_addr; p++) {
1413 void *data = *(void **)p;
1414 unsigned d1 = *((unsigned char *)p - 1);
1415 unsigned d2 = *((unsigned char *)p - 2);
1416 unsigned d3 = *((unsigned char *)p - 3);
1417 unsigned d4 = *((unsigned char *)p - 4);
1419 unsigned d5 = *((unsigned char *)p - 5);
1420 unsigned d6 = *((unsigned char *)p - 6);
1423 /* Check for code references. */
1424 /* Check for a 32 bit word that looks like an absolute
1425 reference to within the code adea of the code object. */
1426 if ((data >= (code_start_addr-displacement))
1427 && (data < (code_end_addr-displacement))) {
1428 /* function header */
1430 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) == (unsigned)code)) {
1431 /* Skip the function header */
1435 /* the case of PUSH imm32 */
1439 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1440 p, d6, d5, d4, d3, d2, d1, data));
1441 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1443 /* the case of MOV [reg-8],imm32 */
1445 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1446 || d2==0x45 || d2==0x46 || d2==0x47)
1450 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1451 p, d6, d5, d4, d3, d2, d1, data));
1452 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1454 /* the case of LEA reg,[disp32] */
1455 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1458 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1459 p, d6, d5, d4, d3, d2, d1, data));
1460 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1464 /* Check for constant references. */
1465 /* Check for a 32 bit word that looks like an absolute
1466 reference to within the constant vector. Constant references
1468 if ((data >= (constants_start_addr-displacement))
1469 && (data < (constants_end_addr-displacement))
1470 && (((unsigned)data & 0x3) == 0)) {
1475 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1476 p, d6, d5, d4, d3, d2, d1, data));
1477 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1480 /* the case of MOV m32,EAX */
1484 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1485 p, d6, d5, d4, d3, d2, d1, data));
1486 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1489 /* the case of CMP m32,imm32 */
1490 if ((d1 == 0x3d) && (d2 == 0x81)) {
1493 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1494 p, d6, d5, d4, d3, d2, d1, data));
1496 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1499 /* Check for a mod=00, r/m=101 byte. */
1500 if ((d1 & 0xc7) == 5) {
1505 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1506 p, d6, d5, d4, d3, d2, d1, data));
1507 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1509 /* the case of CMP reg32,m32 */
1513 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1514 p, d6, d5, d4, d3, d2, d1, data));
1515 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1517 /* the case of MOV m32,reg32 */
1521 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1522 p, d6, d5, d4, d3, d2, d1, data));
1523 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1525 /* the case of MOV reg32,m32 */
1529 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1530 p, d6, d5, d4, d3, d2, d1, data));
1531 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1533 /* the case of LEA reg32,m32 */
1537 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1538 p, d6, d5, d4, d3, d2, d1, data));
1539 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1545 /* If anything was found, print some information on the code
1549 "/compiled code object at %x: header words = %d, code words = %d\n",
1550 code, nheader_words, ncode_words));
1552 "/const start = %x, end = %x\n",
1553 constants_start_addr, constants_end_addr));
1555 "/code start = %x, end = %x\n",
1556 code_start_addr, code_end_addr));
1561 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1563 int nheader_words, ncode_words, nwords;
1564 void *constants_start_addr, *constants_end_addr;
1565 void *code_start_addr, *code_end_addr;
1566 lispobj fixups = NIL;
1567 unsigned displacement = (unsigned)new_code - (unsigned)old_code;
1568 struct vector *fixups_vector;
1570 ncode_words = fixnum_value(new_code->code_size);
1571 nheader_words = HeaderValue(*(lispobj *)new_code);
1572 nwords = ncode_words + nheader_words;
1574 "/compiled code object at %x: header words = %d, code words = %d\n",
1575 new_code, nheader_words, ncode_words)); */
1576 constants_start_addr = (void *)new_code + 5*4;
1577 constants_end_addr = (void *)new_code + nheader_words*4;
1578 code_start_addr = (void *)new_code + nheader_words*4;
1579 code_end_addr = (void *)new_code + nwords*4;
1582 "/const start = %x, end = %x\n",
1583 constants_start_addr,constants_end_addr));
1585 "/code start = %x; end = %x\n",
1586 code_start_addr,code_end_addr));
1589 /* The first constant should be a pointer to the fixups for this
1590 code objects. Check. */
1591 fixups = new_code->constants[0];
1593 /* It will be 0 or the unbound-marker if there are no fixups (as
1594 * will be the case if the code object has been purified, for
1595 * example) and will be an other pointer if it is valid. */
1596 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1597 !is_lisp_pointer(fixups)) {
1598 /* Check for possible errors. */
1599 if (check_code_fixups)
1600 sniff_code_object(new_code, displacement);
1605 fixups_vector = (struct vector *)native_pointer(fixups);
1607 /* Could be pointing to a forwarding pointer. */
1608 /* FIXME is this always in from_space? if so, could replace this code with
1609 * forwarding_pointer_p/forwarding_pointer_value */
1610 if (is_lisp_pointer(fixups) &&
1611 (find_page_index((void*)fixups_vector) != -1) &&
1612 (fixups_vector->header == 0x01)) {
1613 /* If so, then follow it. */
1614 /*SHOW("following pointer to a forwarding pointer");*/
1615 fixups_vector = (struct vector *)native_pointer((lispobj)fixups_vector->length);
1618 /*SHOW("got fixups");*/
1620 if (widetag_of(fixups_vector->header) ==
1621 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
1622 /* Got the fixups for the code block. Now work through the vector,
1623 and apply a fixup at each address. */
1624 int length = fixnum_value(fixups_vector->length);
1626 for (i = 0; i < length; i++) {
1627 unsigned offset = fixups_vector->data[i];
1628 /* Now check the current value of offset. */
1629 unsigned old_value =
1630 *(unsigned *)((unsigned)code_start_addr + offset);
1632 /* If it's within the old_code object then it must be an
1633 * absolute fixup (relative ones are not saved) */
1634 if ((old_value >= (unsigned)old_code)
1635 && (old_value < ((unsigned)old_code + nwords*4)))
1636 /* So add the dispacement. */
1637 *(unsigned *)((unsigned)code_start_addr + offset) =
1638 old_value + displacement;
1640 /* It is outside the old code object so it must be a
1641 * relative fixup (absolute fixups are not saved). So
1642 * subtract the displacement. */
1643 *(unsigned *)((unsigned)code_start_addr + offset) =
1644 old_value - displacement;
1648 /* Check for possible errors. */
1649 if (check_code_fixups) {
1650 sniff_code_object(new_code,displacement);
1656 trans_boxed_large(lispobj object)
1659 unsigned long length;
1661 gc_assert(is_lisp_pointer(object));
1663 header = *((lispobj *) native_pointer(object));
1664 length = HeaderValue(header) + 1;
1665 length = CEILING(length, 2);
1667 return copy_large_object(object, length);
1672 trans_unboxed_large(lispobj object)
1675 unsigned long length;
1678 gc_assert(is_lisp_pointer(object));
1680 header = *((lispobj *) native_pointer(object));
1681 length = HeaderValue(header) + 1;
1682 length = CEILING(length, 2);
1684 return copy_large_unboxed_object(object, length);
1689 * vector-like objects
1693 /* FIXME: What does this mean? */
1694 int gencgc_hash = 1;
1697 scav_vector(lispobj *where, lispobj object)
1699 unsigned int kv_length;
1701 unsigned int length = 0; /* (0 = dummy to stop GCC warning) */
1702 lispobj *hash_table;
1703 lispobj empty_symbol;
1704 unsigned int *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1705 unsigned int *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1706 unsigned int *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1708 unsigned next_vector_length = 0;
1710 /* FIXME: A comment explaining this would be nice. It looks as
1711 * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
1712 * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
1713 if (HeaderValue(object) != subtype_VectorValidHashing)
1717 /* This is set for backward compatibility. FIXME: Do we need
1720 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
1724 kv_length = fixnum_value(where[1]);
1725 kv_vector = where + 2; /* Skip the header and length. */
1726 /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
1728 /* Scavenge element 0, which may be a hash-table structure. */
1729 scavenge(where+2, 1);
1730 if (!is_lisp_pointer(where[2])) {
1731 lose("no pointer at %x in hash table", where[2]);
1733 hash_table = (lispobj *)native_pointer(where[2]);
1734 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1735 if (widetag_of(hash_table[0]) != INSTANCE_HEADER_WIDETAG) {
1736 lose("hash table not instance (%x at %x)", hash_table[0], hash_table);
1739 /* Scavenge element 1, which should be some internal symbol that
1740 * the hash table code reserves for marking empty slots. */
1741 scavenge(where+3, 1);
1742 if (!is_lisp_pointer(where[3])) {
1743 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1745 empty_symbol = where[3];
1746 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1747 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1748 SYMBOL_HEADER_WIDETAG) {
1749 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1750 *(lispobj *)native_pointer(empty_symbol));
1753 /* Scavenge hash table, which will fix the positions of the other
1754 * needed objects. */
1755 scavenge(hash_table, 16);
1757 /* Cross-check the kv_vector. */
1758 if (where != (lispobj *)native_pointer(hash_table[9])) {
1759 lose("hash_table table!=this table %x", hash_table[9]);
1763 weak_p_obj = hash_table[10];
1767 lispobj index_vector_obj = hash_table[13];
1769 if (is_lisp_pointer(index_vector_obj) &&
1770 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1771 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1772 index_vector = ((unsigned int *)native_pointer(index_vector_obj)) + 2;
1773 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1774 length = fixnum_value(((unsigned int *)native_pointer(index_vector_obj))[1]);
1775 /*FSHOW((stderr, "/length = %d\n", length));*/
1777 lose("invalid index_vector %x", index_vector_obj);
1783 lispobj next_vector_obj = hash_table[14];
1785 if (is_lisp_pointer(next_vector_obj) &&
1786 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1787 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1788 next_vector = ((unsigned int *)native_pointer(next_vector_obj)) + 2;
1789 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1790 next_vector_length = fixnum_value(((unsigned int *)native_pointer(next_vector_obj))[1]);
1791 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1793 lose("invalid next_vector %x", next_vector_obj);
1797 /* maybe hash vector */
1799 /* FIXME: This bare "15" offset should become a symbolic
1800 * expression of some sort. And all the other bare offsets
1801 * too. And the bare "16" in scavenge(hash_table, 16). And
1802 * probably other stuff too. Ugh.. */
1803 lispobj hash_vector_obj = hash_table[15];
1805 if (is_lisp_pointer(hash_vector_obj) &&
1806 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj))
1807 == SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1808 hash_vector = ((unsigned int *)native_pointer(hash_vector_obj)) + 2;
1809 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1810 gc_assert(fixnum_value(((unsigned int *)native_pointer(hash_vector_obj))[1])
1811 == next_vector_length);
1814 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1818 /* These lengths could be different as the index_vector can be a
1819 * different length from the others, a larger index_vector could help
1820 * reduce collisions. */
1821 gc_assert(next_vector_length*2 == kv_length);
1823 /* now all set up.. */
1825 /* Work through the KV vector. */
1828 for (i = 1; i < next_vector_length; i++) {
1829 lispobj old_key = kv_vector[2*i];
1830 unsigned int old_index = (old_key & 0x1fffffff)%length;
1832 /* Scavenge the key and value. */
1833 scavenge(&kv_vector[2*i],2);
1835 /* Check whether the key has moved and is EQ based. */
1837 lispobj new_key = kv_vector[2*i];
1838 unsigned int new_index = (new_key & 0x1fffffff)%length;
1840 if ((old_index != new_index) &&
1841 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1842 ((new_key != empty_symbol) ||
1843 (kv_vector[2*i] != empty_symbol))) {
1846 "* EQ key %d moved from %x to %x; index %d to %d\n",
1847 i, old_key, new_key, old_index, new_index));*/
1849 if (index_vector[old_index] != 0) {
1850 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1852 /* Unlink the key from the old_index chain. */
1853 if (index_vector[old_index] == i) {
1854 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1855 index_vector[old_index] = next_vector[i];
1856 /* Link it into the needing rehash chain. */
1857 next_vector[i] = fixnum_value(hash_table[11]);
1858 hash_table[11] = make_fixnum(i);
1861 unsigned prior = index_vector[old_index];
1862 unsigned next = next_vector[prior];
1864 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1867 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1870 next_vector[prior] = next_vector[next];
1871 /* Link it into the needing rehash
1874 fixnum_value(hash_table[11]);
1875 hash_table[11] = make_fixnum(next);
1880 next = next_vector[next];
1888 return (CEILING(kv_length + 2, 2));
1897 /* XX This is a hack adapted from cgc.c. These don't work too
1898 * efficiently with the gencgc as a list of the weak pointers is
1899 * maintained within the objects which causes writes to the pages. A
1900 * limited attempt is made to avoid unnecessary writes, but this needs
1902 #define WEAK_POINTER_NWORDS \
1903 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1906 scav_weak_pointer(lispobj *where, lispobj object)
1908 struct weak_pointer *wp = weak_pointers;
1909 /* Push the weak pointer onto the list of weak pointers.
1910 * Do I have to watch for duplicates? Originally this was
1911 * part of trans_weak_pointer but that didn't work in the
1912 * case where the WP was in a promoted region.
1915 /* Check whether it's already in the list. */
1916 while (wp != NULL) {
1917 if (wp == (struct weak_pointer*)where) {
1923 /* Add it to the start of the list. */
1924 wp = (struct weak_pointer*)where;
1925 if (wp->next != weak_pointers) {
1926 wp->next = weak_pointers;
1928 /*SHOW("avoided write to weak pointer");*/
1933 /* Do not let GC scavenge the value slot of the weak pointer.
1934 * (That is why it is a weak pointer.) */
1936 return WEAK_POINTER_NWORDS;
1940 /* Scan an area looking for an object which encloses the given pointer.
1941 * Return the object start on success or NULL on failure. */
1943 search_space(lispobj *start, size_t words, lispobj *pointer)
1947 lispobj thing = *start;
1949 /* If thing is an immediate then this is a cons. */
1950 if (is_lisp_pointer(thing)
1951 || ((thing & 3) == 0) /* fixnum */
1952 || (widetag_of(thing) == BASE_CHAR_WIDETAG)
1953 || (widetag_of(thing) == UNBOUND_MARKER_WIDETAG))
1956 count = (sizetab[widetag_of(thing)])(start);
1958 /* Check whether the pointer is within this object. */
1959 if ((pointer >= start) && (pointer < (start+count))) {
1961 /*FSHOW((stderr,"/found %x in %x %x\n", pointer, start, thing));*/
1965 /* Round up the count. */
1966 count = CEILING(count,2);
1975 search_read_only_space(lispobj *pointer)
1977 lispobj* start = (lispobj*)READ_ONLY_SPACE_START;
1978 lispobj* end = (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1979 if ((pointer < start) || (pointer >= end))
1981 return (search_space(start, (pointer+2)-start, pointer));
1985 search_static_space(lispobj *pointer)
1987 lispobj* start = (lispobj*)STATIC_SPACE_START;
1988 lispobj* end = (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1989 if ((pointer < start) || (pointer >= end))
1991 return (search_space(start, (pointer+2)-start, pointer));
1994 /* a faster version for searching the dynamic space. This will work even
1995 * if the object is in a current allocation region. */
1997 search_dynamic_space(lispobj *pointer)
1999 int page_index = find_page_index(pointer);
2002 /* The address may be invalid, so do some checks. */
2003 if ((page_index == -1) ||
2004 (page_table[page_index].allocated == FREE_PAGE_FLAG))
2006 start = (lispobj *)((void *)page_address(page_index)
2007 + page_table[page_index].first_object_offset);
2008 return (search_space(start, (pointer+2)-start, pointer));
2011 /* Is there any possibility that pointer is a valid Lisp object
2012 * reference, and/or something else (e.g. subroutine call return
2013 * address) which should prevent us from moving the referred-to thing?
2014 * This is called from preserve_pointers() */
2016 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2018 lispobj *start_addr;
2020 /* Find the object start address. */
2021 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2025 /* We need to allow raw pointers into Code objects for return
2026 * addresses. This will also pick up pointers to functions in code
2028 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2029 /* XXX could do some further checks here */
2033 /* If it's not a return address then it needs to be a valid Lisp
2035 if (!is_lisp_pointer((lispobj)pointer)) {
2039 /* Check that the object pointed to is consistent with the pointer
2042 switch (lowtag_of((lispobj)pointer)) {
2043 case FUN_POINTER_LOWTAG:
2044 /* Start_addr should be the enclosing code object, or a closure
2046 switch (widetag_of(*start_addr)) {
2047 case CODE_HEADER_WIDETAG:
2048 /* This case is probably caught above. */
2050 case CLOSURE_HEADER_WIDETAG:
2051 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2052 if ((unsigned)pointer !=
2053 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2057 pointer, start_addr, *start_addr));
2065 pointer, start_addr, *start_addr));
2069 case LIST_POINTER_LOWTAG:
2070 if ((unsigned)pointer !=
2071 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2075 pointer, start_addr, *start_addr));
2078 /* Is it plausible cons? */
2079 if ((is_lisp_pointer(start_addr[0])
2080 || ((start_addr[0] & 3) == 0) /* fixnum */
2081 || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
2082 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2083 && (is_lisp_pointer(start_addr[1])
2084 || ((start_addr[1] & 3) == 0) /* fixnum */
2085 || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
2086 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2092 pointer, start_addr, *start_addr));
2095 case INSTANCE_POINTER_LOWTAG:
2096 if ((unsigned)pointer !=
2097 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2101 pointer, start_addr, *start_addr));
2104 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2108 pointer, start_addr, *start_addr));
2112 case OTHER_POINTER_LOWTAG:
2113 if ((unsigned)pointer !=
2114 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2118 pointer, start_addr, *start_addr));
2121 /* Is it plausible? Not a cons. XXX should check the headers. */
2122 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2126 pointer, start_addr, *start_addr));
2129 switch (widetag_of(start_addr[0])) {
2130 case UNBOUND_MARKER_WIDETAG:
2131 case BASE_CHAR_WIDETAG:
2135 pointer, start_addr, *start_addr));
2138 /* only pointed to by function pointers? */
2139 case CLOSURE_HEADER_WIDETAG:
2140 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2144 pointer, start_addr, *start_addr));
2147 case INSTANCE_HEADER_WIDETAG:
2151 pointer, start_addr, *start_addr));
2154 /* the valid other immediate pointer objects */
2155 case SIMPLE_VECTOR_WIDETAG:
2157 case COMPLEX_WIDETAG:
2158 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2159 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2161 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2162 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2164 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2165 case COMPLEX_LONG_FLOAT_WIDETAG:
2167 case SIMPLE_ARRAY_WIDETAG:
2168 case COMPLEX_BASE_STRING_WIDETAG:
2169 case COMPLEX_VECTOR_NIL_WIDETAG:
2170 case COMPLEX_BIT_VECTOR_WIDETAG:
2171 case COMPLEX_VECTOR_WIDETAG:
2172 case COMPLEX_ARRAY_WIDETAG:
2173 case VALUE_CELL_HEADER_WIDETAG:
2174 case SYMBOL_HEADER_WIDETAG:
2176 case CODE_HEADER_WIDETAG:
2177 case BIGNUM_WIDETAG:
2178 case SINGLE_FLOAT_WIDETAG:
2179 case DOUBLE_FLOAT_WIDETAG:
2180 #ifdef LONG_FLOAT_WIDETAG
2181 case LONG_FLOAT_WIDETAG:
2183 case SIMPLE_BASE_STRING_WIDETAG:
2184 case SIMPLE_BIT_VECTOR_WIDETAG:
2185 case SIMPLE_ARRAY_NIL_WIDETAG:
2186 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2187 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2188 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2189 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2190 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2191 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2192 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2193 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2194 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2195 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2196 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2198 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2199 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2201 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2202 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2204 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2205 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2207 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2208 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2209 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2210 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2212 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2213 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2215 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2216 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2218 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2219 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2222 case WEAK_POINTER_WIDETAG:
2229 pointer, start_addr, *start_addr));
2237 pointer, start_addr, *start_addr));
2245 /* Adjust large bignum and vector objects. This will adjust the
2246 * allocated region if the size has shrunk, and move unboxed objects
2247 * into unboxed pages. The pages are not promoted here, and the
2248 * promoted region is not added to the new_regions; this is really
2249 * only designed to be called from preserve_pointer(). Shouldn't fail
2250 * if this is missed, just may delay the moving of objects to unboxed
2251 * pages, and the freeing of pages. */
2253 maybe_adjust_large_object(lispobj *where)
2258 int remaining_bytes;
2265 /* Check whether it's a vector or bignum object. */
2266 switch (widetag_of(where[0])) {
2267 case SIMPLE_VECTOR_WIDETAG:
2268 boxed = BOXED_PAGE_FLAG;
2270 case BIGNUM_WIDETAG:
2271 case SIMPLE_BASE_STRING_WIDETAG:
2272 case SIMPLE_BIT_VECTOR_WIDETAG:
2273 case SIMPLE_ARRAY_NIL_WIDETAG:
2274 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2275 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2276 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2277 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2278 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2279 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2280 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2281 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2282 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2283 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2284 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2286 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2287 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2289 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2290 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2292 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2293 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2295 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2296 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2297 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2298 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2300 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2301 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2303 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2304 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2306 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2307 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2309 boxed = UNBOXED_PAGE_FLAG;
2315 /* Find its current size. */
2316 nwords = (sizetab[widetag_of(where[0])])(where);
2318 first_page = find_page_index((void *)where);
2319 gc_assert(first_page >= 0);
2321 /* Note: Any page write-protection must be removed, else a later
2322 * scavenge_newspace may incorrectly not scavenge these pages.
2323 * This would not be necessary if they are added to the new areas,
2324 * but lets do it for them all (they'll probably be written
2327 gc_assert(page_table[first_page].first_object_offset == 0);
2329 next_page = first_page;
2330 remaining_bytes = nwords*4;
2331 while (remaining_bytes > PAGE_BYTES) {
2332 gc_assert(page_table[next_page].gen == from_space);
2333 gc_assert((page_table[next_page].allocated == BOXED_PAGE_FLAG)
2334 || (page_table[next_page].allocated == UNBOXED_PAGE_FLAG));
2335 gc_assert(page_table[next_page].large_object);
2336 gc_assert(page_table[next_page].first_object_offset ==
2337 -PAGE_BYTES*(next_page-first_page));
2338 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2340 page_table[next_page].allocated = boxed;
2342 /* Shouldn't be write-protected at this stage. Essential that the
2344 gc_assert(!page_table[next_page].write_protected);
2345 remaining_bytes -= PAGE_BYTES;
2349 /* Now only one page remains, but the object may have shrunk so
2350 * there may be more unused pages which will be freed. */
2352 /* Object may have shrunk but shouldn't have grown - check. */
2353 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2355 page_table[next_page].allocated = boxed;
2356 gc_assert(page_table[next_page].allocated ==
2357 page_table[first_page].allocated);
2359 /* Adjust the bytes_used. */
2360 old_bytes_used = page_table[next_page].bytes_used;
2361 page_table[next_page].bytes_used = remaining_bytes;
2363 bytes_freed = old_bytes_used - remaining_bytes;
2365 /* Free any remaining pages; needs care. */
2367 while ((old_bytes_used == PAGE_BYTES) &&
2368 (page_table[next_page].gen == from_space) &&
2369 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
2370 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
2371 page_table[next_page].large_object &&
2372 (page_table[next_page].first_object_offset ==
2373 -(next_page - first_page)*PAGE_BYTES)) {
2374 /* It checks out OK, free the page. We don't need to both zeroing
2375 * pages as this should have been done before shrinking the
2376 * object. These pages shouldn't be write protected as they
2377 * should be zero filled. */
2378 gc_assert(page_table[next_page].write_protected == 0);
2380 old_bytes_used = page_table[next_page].bytes_used;
2381 page_table[next_page].allocated = FREE_PAGE_FLAG;
2382 page_table[next_page].bytes_used = 0;
2383 bytes_freed += old_bytes_used;
2387 if ((bytes_freed > 0) && gencgc_verbose) {
2389 "/maybe_adjust_large_object() freed %d\n",
2393 generations[from_space].bytes_allocated -= bytes_freed;
2394 bytes_allocated -= bytes_freed;
2399 /* Take a possible pointer to a Lisp object and mark its page in the
2400 * page_table so that it will not be relocated during a GC.
2402 * This involves locating the page it points to, then backing up to
2403 * the start of its region, then marking all pages dont_move from there
2404 * up to the first page that's not full or has a different generation
2406 * It is assumed that all the page static flags have been cleared at
2407 * the start of a GC.
2409 * It is also assumed that the current gc_alloc() region has been
2410 * flushed and the tables updated. */
2412 preserve_pointer(void *addr)
2414 int addr_page_index = find_page_index(addr);
2417 unsigned region_allocation;
2419 /* quick check 1: Address is quite likely to have been invalid. */
2420 if ((addr_page_index == -1)
2421 || (page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2422 || (page_table[addr_page_index].bytes_used == 0)
2423 || (page_table[addr_page_index].gen != from_space)
2424 /* Skip if already marked dont_move. */
2425 || (page_table[addr_page_index].dont_move != 0))
2427 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2428 /* (Now that we know that addr_page_index is in range, it's
2429 * safe to index into page_table[] with it.) */
2430 region_allocation = page_table[addr_page_index].allocated;
2432 /* quick check 2: Check the offset within the page.
2435 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2438 /* Filter out anything which can't be a pointer to a Lisp object
2439 * (or, as a special case which also requires dont_move, a return
2440 * address referring to something in a CodeObject). This is
2441 * expensive but important, since it vastly reduces the
2442 * probability that random garbage will be bogusly interpreted as
2443 * a pointer which prevents a page from moving. */
2444 if (!(possibly_valid_dynamic_space_pointer(addr)))
2447 /* Find the beginning of the region. Note that there may be
2448 * objects in the region preceding the one that we were passed a
2449 * pointer to: if this is the case, we will write-protect all the
2450 * previous objects' pages too. */
2453 /* I think this'd work just as well, but without the assertions.
2454 * -dan 2004.01.01 */
2456 find_page_index(page_address(addr_page_index)+
2457 page_table[addr_page_index].first_object_offset);
2459 first_page = addr_page_index;
2460 while (page_table[first_page].first_object_offset != 0) {
2462 /* Do some checks. */
2463 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2464 gc_assert(page_table[first_page].gen == from_space);
2465 gc_assert(page_table[first_page].allocated == region_allocation);
2469 /* Adjust any large objects before promotion as they won't be
2470 * copied after promotion. */
2471 if (page_table[first_page].large_object) {
2472 maybe_adjust_large_object(page_address(first_page));
2473 /* If a large object has shrunk then addr may now point to a
2474 * free area in which case it's ignored here. Note it gets
2475 * through the valid pointer test above because the tail looks
2477 if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2478 || (page_table[addr_page_index].bytes_used == 0)
2479 /* Check the offset within the page. */
2480 || (((unsigned)addr & (PAGE_BYTES - 1))
2481 > page_table[addr_page_index].bytes_used)) {
2483 "weird? ignore ptr 0x%x to freed area of large object\n",
2487 /* It may have moved to unboxed pages. */
2488 region_allocation = page_table[first_page].allocated;
2491 /* Now work forward until the end of this contiguous area is found,
2492 * marking all pages as dont_move. */
2493 for (i = first_page; ;i++) {
2494 gc_assert(page_table[i].allocated == region_allocation);
2496 /* Mark the page static. */
2497 page_table[i].dont_move = 1;
2499 /* Move the page to the new_space. XX I'd rather not do this
2500 * but the GC logic is not quite able to copy with the static
2501 * pages remaining in the from space. This also requires the
2502 * generation bytes_allocated counters be updated. */
2503 page_table[i].gen = new_space;
2504 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2505 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2507 /* It is essential that the pages are not write protected as
2508 * they may have pointers into the old-space which need
2509 * scavenging. They shouldn't be write protected at this
2511 gc_assert(!page_table[i].write_protected);
2513 /* Check whether this is the last page in this contiguous block.. */
2514 if ((page_table[i].bytes_used < PAGE_BYTES)
2515 /* ..or it is PAGE_BYTES and is the last in the block */
2516 || (page_table[i+1].allocated == FREE_PAGE_FLAG)
2517 || (page_table[i+1].bytes_used == 0) /* next page free */
2518 || (page_table[i+1].gen != from_space) /* diff. gen */
2519 || (page_table[i+1].first_object_offset == 0))
2523 /* Check that the page is now static. */
2524 gc_assert(page_table[addr_page_index].dont_move != 0);
2527 /* If the given page is not write-protected, then scan it for pointers
2528 * to younger generations or the top temp. generation, if no
2529 * suspicious pointers are found then the page is write-protected.
2531 * Care is taken to check for pointers to the current gc_alloc()
2532 * region if it is a younger generation or the temp. generation. This
2533 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2534 * the gc_alloc_generation does not need to be checked as this is only
2535 * called from scavenge_generation() when the gc_alloc generation is
2536 * younger, so it just checks if there is a pointer to the current
2539 * We return 1 if the page was write-protected, else 0. */
2541 update_page_write_prot(int page)
2543 int gen = page_table[page].gen;
2546 void **page_addr = (void **)page_address(page);
2547 int num_words = page_table[page].bytes_used / 4;
2549 /* Shouldn't be a free page. */
2550 gc_assert(page_table[page].allocated != FREE_PAGE_FLAG);
2551 gc_assert(page_table[page].bytes_used != 0);
2553 /* Skip if it's already write-protected, pinned, or unboxed */
2554 if (page_table[page].write_protected
2555 || page_table[page].dont_move
2556 || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
2559 /* Scan the page for pointers to younger generations or the
2560 * top temp. generation. */
2562 for (j = 0; j < num_words; j++) {
2563 void *ptr = *(page_addr+j);
2564 int index = find_page_index(ptr);
2566 /* Check that it's in the dynamic space */
2568 if (/* Does it point to a younger or the temp. generation? */
2569 ((page_table[index].allocated != FREE_PAGE_FLAG)
2570 && (page_table[index].bytes_used != 0)
2571 && ((page_table[index].gen < gen)
2572 || (page_table[index].gen == NUM_GENERATIONS)))
2574 /* Or does it point within a current gc_alloc() region? */
2575 || ((boxed_region.start_addr <= ptr)
2576 && (ptr <= boxed_region.free_pointer))
2577 || ((unboxed_region.start_addr <= ptr)
2578 && (ptr <= unboxed_region.free_pointer))) {
2585 /* Write-protect the page. */
2586 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2588 os_protect((void *)page_addr,
2590 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2592 /* Note the page as protected in the page tables. */
2593 page_table[page].write_protected = 1;
2599 /* Scavenge a generation.
2601 * This will not resolve all pointers when generation is the new
2602 * space, as new objects may be added which are not checked here - use
2603 * scavenge_newspace generation.
2605 * Write-protected pages should not have any pointers to the
2606 * from_space so do need scavenging; thus write-protected pages are
2607 * not always scavenged. There is some code to check that these pages
2608 * are not written; but to check fully the write-protected pages need
2609 * to be scavenged by disabling the code to skip them.
2611 * Under the current scheme when a generation is GCed the younger
2612 * generations will be empty. So, when a generation is being GCed it
2613 * is only necessary to scavenge the older generations for pointers
2614 * not the younger. So a page that does not have pointers to younger
2615 * generations does not need to be scavenged.
2617 * The write-protection can be used to note pages that don't have
2618 * pointers to younger pages. But pages can be written without having
2619 * pointers to younger generations. After the pages are scavenged here
2620 * they can be scanned for pointers to younger generations and if
2621 * there are none the page can be write-protected.
2623 * One complication is when the newspace is the top temp. generation.
2625 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2626 * that none were written, which they shouldn't be as they should have
2627 * no pointers to younger generations. This breaks down for weak
2628 * pointers as the objects contain a link to the next and are written
2629 * if a weak pointer is scavenged. Still it's a useful check. */
2631 scavenge_generation(int generation)
2638 /* Clear the write_protected_cleared flags on all pages. */
2639 for (i = 0; i < NUM_PAGES; i++)
2640 page_table[i].write_protected_cleared = 0;
2643 for (i = 0; i < last_free_page; i++) {
2644 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2645 && (page_table[i].bytes_used != 0)
2646 && (page_table[i].gen == generation)) {
2648 int write_protected=1;
2650 /* This should be the start of a region */
2651 gc_assert(page_table[i].first_object_offset == 0);
2653 /* Now work forward until the end of the region */
2654 for (last_page = i; ; last_page++) {
2656 write_protected && page_table[last_page].write_protected;
2657 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2658 /* Or it is PAGE_BYTES and is the last in the block */
2659 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2660 || (page_table[last_page+1].bytes_used == 0)
2661 || (page_table[last_page+1].gen != generation)
2662 || (page_table[last_page+1].first_object_offset == 0))
2665 if (!write_protected) {
2666 scavenge(page_address(i), (page_table[last_page].bytes_used
2667 + (last_page-i)*PAGE_BYTES)/4);
2669 /* Now scan the pages and write protect those that
2670 * don't have pointers to younger generations. */
2671 if (enable_page_protection) {
2672 for (j = i; j <= last_page; j++) {
2673 num_wp += update_page_write_prot(j);
2680 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2682 "/write protected %d pages within generation %d\n",
2683 num_wp, generation));
2687 /* Check that none of the write_protected pages in this generation
2688 * have been written to. */
2689 for (i = 0; i < NUM_PAGES; i++) {
2690 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2691 && (page_table[i].bytes_used != 0)
2692 && (page_table[i].gen == generation)
2693 && (page_table[i].write_protected_cleared != 0)) {
2694 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2696 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2697 page_table[i].bytes_used,
2698 page_table[i].first_object_offset,
2699 page_table[i].dont_move));
2700 lose("write to protected page %d in scavenge_generation()", i);
2707 /* Scavenge a newspace generation. As it is scavenged new objects may
2708 * be allocated to it; these will also need to be scavenged. This
2709 * repeats until there are no more objects unscavenged in the
2710 * newspace generation.
2712 * To help improve the efficiency, areas written are recorded by
2713 * gc_alloc() and only these scavenged. Sometimes a little more will be
2714 * scavenged, but this causes no harm. An easy check is done that the
2715 * scavenged bytes equals the number allocated in the previous
2718 * Write-protected pages are not scanned except if they are marked
2719 * dont_move in which case they may have been promoted and still have
2720 * pointers to the from space.
2722 * Write-protected pages could potentially be written by alloc however
2723 * to avoid having to handle re-scavenging of write-protected pages
2724 * gc_alloc() does not write to write-protected pages.
2726 * New areas of objects allocated are recorded alternatively in the two
2727 * new_areas arrays below. */
2728 static struct new_area new_areas_1[NUM_NEW_AREAS];
2729 static struct new_area new_areas_2[NUM_NEW_AREAS];
2731 /* Do one full scan of the new space generation. This is not enough to
2732 * complete the job as new objects may be added to the generation in
2733 * the process which are not scavenged. */
2735 scavenge_newspace_generation_one_scan(int generation)
2740 "/starting one full scan of newspace generation %d\n",
2742 for (i = 0; i < last_free_page; i++) {
2743 /* Note that this skips over open regions when it encounters them. */
2744 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2745 && (page_table[i].bytes_used != 0)
2746 && (page_table[i].gen == generation)
2747 && ((page_table[i].write_protected == 0)
2748 /* (This may be redundant as write_protected is now
2749 * cleared before promotion.) */
2750 || (page_table[i].dont_move == 1))) {
2754 /* The scavenge will start at the first_object_offset of page i.
2756 * We need to find the full extent of this contiguous
2757 * block in case objects span pages.
2759 * Now work forward until the end of this contiguous area
2760 * is found. A small area is preferred as there is a
2761 * better chance of its pages being write-protected. */
2762 for (last_page = i; ;last_page++) {
2763 /* If all pages are write-protected and movable,
2764 * then no need to scavenge */
2765 all_wp=all_wp && page_table[last_page].write_protected &&
2766 !page_table[last_page].dont_move;
2768 /* Check whether this is the last page in this
2769 * contiguous block */
2770 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2771 /* Or it is PAGE_BYTES and is the last in the block */
2772 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2773 || (page_table[last_page+1].bytes_used == 0)
2774 || (page_table[last_page+1].gen != generation)
2775 || (page_table[last_page+1].first_object_offset == 0))
2779 /* Do a limited check for write-protected pages. */
2783 size = (page_table[last_page].bytes_used
2784 + (last_page-i)*PAGE_BYTES
2785 - page_table[i].first_object_offset)/4;
2786 new_areas_ignore_page = last_page;
2788 scavenge(page_address(i) +
2789 page_table[i].first_object_offset,
2797 "/done with one full scan of newspace generation %d\n",
2801 /* Do a complete scavenge of the newspace generation. */
2803 scavenge_newspace_generation(int generation)
2807 /* the new_areas array currently being written to by gc_alloc() */
2808 struct new_area (*current_new_areas)[] = &new_areas_1;
2809 int current_new_areas_index;
2811 /* the new_areas created by the previous scavenge cycle */
2812 struct new_area (*previous_new_areas)[] = NULL;
2813 int previous_new_areas_index;
2815 /* Flush the current regions updating the tables. */
2816 gc_alloc_update_all_page_tables();
2818 /* Turn on the recording of new areas by gc_alloc(). */
2819 new_areas = current_new_areas;
2820 new_areas_index = 0;
2822 /* Don't need to record new areas that get scavenged anyway during
2823 * scavenge_newspace_generation_one_scan. */
2824 record_new_objects = 1;
2826 /* Start with a full scavenge. */
2827 scavenge_newspace_generation_one_scan(generation);
2829 /* Record all new areas now. */
2830 record_new_objects = 2;
2832 /* Flush the current regions updating the tables. */
2833 gc_alloc_update_all_page_tables();
2835 /* Grab new_areas_index. */
2836 current_new_areas_index = new_areas_index;
2839 "The first scan is finished; current_new_areas_index=%d.\n",
2840 current_new_areas_index));*/
2842 while (current_new_areas_index > 0) {
2843 /* Move the current to the previous new areas */
2844 previous_new_areas = current_new_areas;
2845 previous_new_areas_index = current_new_areas_index;
2847 /* Scavenge all the areas in previous new areas. Any new areas
2848 * allocated are saved in current_new_areas. */
2850 /* Allocate an array for current_new_areas; alternating between
2851 * new_areas_1 and 2 */
2852 if (previous_new_areas == &new_areas_1)
2853 current_new_areas = &new_areas_2;
2855 current_new_areas = &new_areas_1;
2857 /* Set up for gc_alloc(). */
2858 new_areas = current_new_areas;
2859 new_areas_index = 0;
2861 /* Check whether previous_new_areas had overflowed. */
2862 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2864 /* New areas of objects allocated have been lost so need to do a
2865 * full scan to be sure! If this becomes a problem try
2866 * increasing NUM_NEW_AREAS. */
2868 SHOW("new_areas overflow, doing full scavenge");
2870 /* Don't need to record new areas that get scavenge anyway
2871 * during scavenge_newspace_generation_one_scan. */
2872 record_new_objects = 1;
2874 scavenge_newspace_generation_one_scan(generation);
2876 /* Record all new areas now. */
2877 record_new_objects = 2;
2879 /* Flush the current regions updating the tables. */
2880 gc_alloc_update_all_page_tables();
2884 /* Work through previous_new_areas. */
2885 for (i = 0; i < previous_new_areas_index; i++) {
2886 /* FIXME: All these bare *4 and /4 should be something
2887 * like BYTES_PER_WORD or WBYTES. */
2888 int page = (*previous_new_areas)[i].page;
2889 int offset = (*previous_new_areas)[i].offset;
2890 int size = (*previous_new_areas)[i].size / 4;
2891 gc_assert((*previous_new_areas)[i].size % 4 == 0);
2892 scavenge(page_address(page)+offset, size);
2895 /* Flush the current regions updating the tables. */
2896 gc_alloc_update_all_page_tables();
2899 current_new_areas_index = new_areas_index;
2902 "The re-scan has finished; current_new_areas_index=%d.\n",
2903 current_new_areas_index));*/
2906 /* Turn off recording of areas allocated by gc_alloc(). */
2907 record_new_objects = 0;
2910 /* Check that none of the write_protected pages in this generation
2911 * have been written to. */
2912 for (i = 0; i < NUM_PAGES; i++) {
2913 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2914 && (page_table[i].bytes_used != 0)
2915 && (page_table[i].gen == generation)
2916 && (page_table[i].write_protected_cleared != 0)
2917 && (page_table[i].dont_move == 0)) {
2918 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2919 i, generation, page_table[i].dont_move);
2925 /* Un-write-protect all the pages in from_space. This is done at the
2926 * start of a GC else there may be many page faults while scavenging
2927 * the newspace (I've seen drive the system time to 99%). These pages
2928 * would need to be unprotected anyway before unmapping in
2929 * free_oldspace; not sure what effect this has on paging.. */
2931 unprotect_oldspace(void)
2935 for (i = 0; i < last_free_page; i++) {
2936 if ((page_table[i].allocated != FREE_PAGE_FLAG)
2937 && (page_table[i].bytes_used != 0)
2938 && (page_table[i].gen == from_space)) {
2941 page_start = (void *)page_address(i);
2943 /* Remove any write-protection. We should be able to rely
2944 * on the write-protect flag to avoid redundant calls. */
2945 if (page_table[i].write_protected) {
2946 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2947 page_table[i].write_protected = 0;
2953 /* Work through all the pages and free any in from_space. This
2954 * assumes that all objects have been copied or promoted to an older
2955 * generation. Bytes_allocated and the generation bytes_allocated
2956 * counter are updated. The number of bytes freed is returned. */
2960 int bytes_freed = 0;
2961 int first_page, last_page;
2966 /* Find a first page for the next region of pages. */
2967 while ((first_page < last_free_page)
2968 && ((page_table[first_page].allocated == FREE_PAGE_FLAG)
2969 || (page_table[first_page].bytes_used == 0)
2970 || (page_table[first_page].gen != from_space)))
2973 if (first_page >= last_free_page)
2976 /* Find the last page of this region. */
2977 last_page = first_page;
2980 /* Free the page. */
2981 bytes_freed += page_table[last_page].bytes_used;
2982 generations[page_table[last_page].gen].bytes_allocated -=
2983 page_table[last_page].bytes_used;
2984 page_table[last_page].allocated = FREE_PAGE_FLAG;
2985 page_table[last_page].bytes_used = 0;
2987 /* Remove any write-protection. We should be able to rely
2988 * on the write-protect flag to avoid redundant calls. */
2990 void *page_start = (void *)page_address(last_page);
2992 if (page_table[last_page].write_protected) {
2993 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2994 page_table[last_page].write_protected = 0;
2999 while ((last_page < last_free_page)
3000 && (page_table[last_page].allocated != FREE_PAGE_FLAG)
3001 && (page_table[last_page].bytes_used != 0)
3002 && (page_table[last_page].gen == from_space));
3004 /* Zero pages from first_page to (last_page-1). */
3005 memset(page_address(first_page), 0, PAGE_BYTES*(last_page-first_page));
3007 first_page = last_page;
3009 } while (first_page < last_free_page);
3011 bytes_allocated -= bytes_freed;
3016 /* Print some information about a pointer at the given address. */
3018 print_ptr(lispobj *addr)
3020 /* If addr is in the dynamic space then out the page information. */
3021 int pi1 = find_page_index((void*)addr);
3024 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3025 (unsigned int) addr,
3027 page_table[pi1].allocated,
3028 page_table[pi1].gen,
3029 page_table[pi1].bytes_used,
3030 page_table[pi1].first_object_offset,
3031 page_table[pi1].dont_move);
3032 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3045 extern int undefined_tramp;
3048 verify_space(lispobj *start, size_t words)
3050 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3051 int is_in_readonly_space =
3052 (READ_ONLY_SPACE_START <= (unsigned)start &&
3053 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3057 lispobj thing = *(lispobj*)start;
3059 if (is_lisp_pointer(thing)) {
3060 int page_index = find_page_index((void*)thing);
3061 int to_readonly_space =
3062 (READ_ONLY_SPACE_START <= thing &&
3063 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3064 int to_static_space =
3065 (STATIC_SPACE_START <= thing &&
3066 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3068 /* Does it point to the dynamic space? */
3069 if (page_index != -1) {
3070 /* If it's within the dynamic space it should point to a used
3071 * page. XX Could check the offset too. */
3072 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
3073 && (page_table[page_index].bytes_used == 0))
3074 lose ("Ptr %x @ %x sees free page.", thing, start);
3075 /* Check that it doesn't point to a forwarding pointer! */
3076 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3077 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3079 /* Check that its not in the RO space as it would then be a
3080 * pointer from the RO to the dynamic space. */
3081 if (is_in_readonly_space) {
3082 lose("ptr to dynamic space %x from RO space %x",
3085 /* Does it point to a plausible object? This check slows
3086 * it down a lot (so it's commented out).
3088 * "a lot" is serious: it ate 50 minutes cpu time on
3089 * my duron 950 before I came back from lunch and
3092 * FIXME: Add a variable to enable this
3095 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3096 lose("ptr %x to invalid object %x", thing, start);
3100 /* Verify that it points to another valid space. */
3101 if (!to_readonly_space && !to_static_space
3102 && (thing != (unsigned)&undefined_tramp)) {
3103 lose("Ptr %x @ %x sees junk.", thing, start);
3107 if (!(fixnump(thing))) {
3109 switch(widetag_of(*start)) {
3112 case SIMPLE_VECTOR_WIDETAG:
3114 case COMPLEX_WIDETAG:
3115 case SIMPLE_ARRAY_WIDETAG:
3116 case COMPLEX_BASE_STRING_WIDETAG:
3117 case COMPLEX_VECTOR_NIL_WIDETAG:
3118 case COMPLEX_BIT_VECTOR_WIDETAG:
3119 case COMPLEX_VECTOR_WIDETAG:
3120 case COMPLEX_ARRAY_WIDETAG:
3121 case CLOSURE_HEADER_WIDETAG:
3122 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3123 case VALUE_CELL_HEADER_WIDETAG:
3124 case SYMBOL_HEADER_WIDETAG:
3125 case BASE_CHAR_WIDETAG:
3126 case UNBOUND_MARKER_WIDETAG:
3127 case INSTANCE_HEADER_WIDETAG:
3132 case CODE_HEADER_WIDETAG:
3134 lispobj object = *start;
3136 int nheader_words, ncode_words, nwords;
3138 struct simple_fun *fheaderp;
3140 code = (struct code *) start;
3142 /* Check that it's not in the dynamic space.
3143 * FIXME: Isn't is supposed to be OK for code
3144 * objects to be in the dynamic space these days? */
3145 if (is_in_dynamic_space
3146 /* It's ok if it's byte compiled code. The trace
3147 * table offset will be a fixnum if it's x86
3148 * compiled code - check.
3150 * FIXME: #^#@@! lack of abstraction here..
3151 * This line can probably go away now that
3152 * there's no byte compiler, but I've got
3153 * too much to worry about right now to try
3154 * to make sure. -- WHN 2001-10-06 */
3155 && fixnump(code->trace_table_offset)
3156 /* Only when enabled */
3157 && verify_dynamic_code_check) {
3159 "/code object at %x in the dynamic space\n",
3163 ncode_words = fixnum_value(code->code_size);
3164 nheader_words = HeaderValue(object);
3165 nwords = ncode_words + nheader_words;
3166 nwords = CEILING(nwords, 2);
3167 /* Scavenge the boxed section of the code data block */
3168 verify_space(start + 1, nheader_words - 1);
3170 /* Scavenge the boxed section of each function
3171 * object in the code data block. */
3172 fheaderl = code->entry_points;
3173 while (fheaderl != NIL) {
3175 (struct simple_fun *) native_pointer(fheaderl);
3176 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3177 verify_space(&fheaderp->name, 1);
3178 verify_space(&fheaderp->arglist, 1);
3179 verify_space(&fheaderp->type, 1);
3180 fheaderl = fheaderp->next;
3186 /* unboxed objects */
3187 case BIGNUM_WIDETAG:
3188 case SINGLE_FLOAT_WIDETAG:
3189 case DOUBLE_FLOAT_WIDETAG:
3190 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3191 case LONG_FLOAT_WIDETAG:
3193 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3194 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3196 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3197 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3199 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3200 case COMPLEX_LONG_FLOAT_WIDETAG:
3202 case SIMPLE_BASE_STRING_WIDETAG:
3203 case SIMPLE_BIT_VECTOR_WIDETAG:
3204 case SIMPLE_ARRAY_NIL_WIDETAG:
3205 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3206 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3207 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3208 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3209 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3210 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3211 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3212 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3213 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3214 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3215 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3217 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3218 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3220 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3221 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3223 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3224 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3226 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3227 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3228 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3229 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3231 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3232 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3234 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3235 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3237 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3238 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3241 case WEAK_POINTER_WIDETAG:
3242 count = (sizetab[widetag_of(*start)])(start);
3258 /* FIXME: It would be nice to make names consistent so that
3259 * foo_size meant size *in* *bytes* instead of size in some
3260 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3261 * Some counts of lispobjs are called foo_count; it might be good
3262 * to grep for all foo_size and rename the appropriate ones to
3264 int read_only_space_size =
3265 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3266 - (lispobj*)READ_ONLY_SPACE_START;
3267 int static_space_size =
3268 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3269 - (lispobj*)STATIC_SPACE_START;
3271 for_each_thread(th) {
3272 int binding_stack_size =
3273 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3274 - (lispobj*)th->binding_stack_start;
3275 verify_space(th->binding_stack_start, binding_stack_size);
3277 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3278 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3282 verify_generation(int generation)
3286 for (i = 0; i < last_free_page; i++) {
3287 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3288 && (page_table[i].bytes_used != 0)
3289 && (page_table[i].gen == generation)) {
3291 int region_allocation = page_table[i].allocated;
3293 /* This should be the start of a contiguous block */
3294 gc_assert(page_table[i].first_object_offset == 0);
3296 /* Need to find the full extent of this contiguous block in case
3297 objects span pages. */
3299 /* Now work forward until the end of this contiguous area is
3301 for (last_page = i; ;last_page++)
3302 /* Check whether this is the last page in this contiguous
3304 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3305 /* Or it is PAGE_BYTES and is the last in the block */
3306 || (page_table[last_page+1].allocated != region_allocation)
3307 || (page_table[last_page+1].bytes_used == 0)
3308 || (page_table[last_page+1].gen != generation)
3309 || (page_table[last_page+1].first_object_offset == 0))
3312 verify_space(page_address(i), (page_table[last_page].bytes_used
3313 + (last_page-i)*PAGE_BYTES)/4);
3319 /* Check that all the free space is zero filled. */
3321 verify_zero_fill(void)
3325 for (page = 0; page < last_free_page; page++) {
3326 if (page_table[page].allocated == FREE_PAGE_FLAG) {
3327 /* The whole page should be zero filled. */
3328 int *start_addr = (int *)page_address(page);
3331 for (i = 0; i < size; i++) {
3332 if (start_addr[i] != 0) {
3333 lose("free page not zero at %x", start_addr + i);
3337 int free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3338 if (free_bytes > 0) {
3339 int *start_addr = (int *)((unsigned)page_address(page)
3340 + page_table[page].bytes_used);
3341 int size = free_bytes / 4;
3343 for (i = 0; i < size; i++) {
3344 if (start_addr[i] != 0) {
3345 lose("free region not zero at %x", start_addr + i);
3353 /* External entry point for verify_zero_fill */
3355 gencgc_verify_zero_fill(void)
3357 /* Flush the alloc regions updating the tables. */
3358 gc_alloc_update_all_page_tables();
3359 SHOW("verifying zero fill");
3364 verify_dynamic_space(void)
3368 for (i = 0; i < NUM_GENERATIONS; i++)
3369 verify_generation(i);
3371 if (gencgc_enable_verify_zero_fill)
3375 /* Write-protect all the dynamic boxed pages in the given generation. */
3377 write_protect_generation_pages(int generation)
3381 gc_assert(generation < NUM_GENERATIONS);
3383 for (i = 0; i < last_free_page; i++)
3384 if ((page_table[i].allocated == BOXED_PAGE_FLAG)
3385 && (page_table[i].bytes_used != 0)
3386 && !page_table[i].dont_move
3387 && (page_table[i].gen == generation)) {
3390 page_start = (void *)page_address(i);
3392 os_protect(page_start,
3394 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3396 /* Note the page as protected in the page tables. */
3397 page_table[i].write_protected = 1;
3400 if (gencgc_verbose > 1) {
3402 "/write protected %d of %d pages in generation %d\n",
3403 count_write_protect_generation_pages(generation),
3404 count_generation_pages(generation),
3409 /* Garbage collect a generation. If raise is 0 then the remains of the
3410 * generation are not raised to the next generation. */
3412 garbage_collect_generation(int generation, int raise)
3414 unsigned long bytes_freed;
3416 unsigned long static_space_size;
3418 gc_assert(generation <= (NUM_GENERATIONS-1));
3420 /* The oldest generation can't be raised. */
3421 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3423 /* Initialize the weak pointer list. */
3424 weak_pointers = NULL;
3426 /* When a generation is not being raised it is transported to a
3427 * temporary generation (NUM_GENERATIONS), and lowered when
3428 * done. Set up this new generation. There should be no pages
3429 * allocated to it yet. */
3431 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3433 /* Set the global src and dest. generations */
3434 from_space = generation;
3436 new_space = generation+1;
3438 new_space = NUM_GENERATIONS;
3440 /* Change to a new space for allocation, resetting the alloc_start_page */
3441 gc_alloc_generation = new_space;
3442 generations[new_space].alloc_start_page = 0;
3443 generations[new_space].alloc_unboxed_start_page = 0;
3444 generations[new_space].alloc_large_start_page = 0;
3445 generations[new_space].alloc_large_unboxed_start_page = 0;
3447 /* Before any pointers are preserved, the dont_move flags on the
3448 * pages need to be cleared. */
3449 for (i = 0; i < last_free_page; i++)
3450 if(page_table[i].gen==from_space)
3451 page_table[i].dont_move = 0;
3453 /* Un-write-protect the old-space pages. This is essential for the
3454 * promoted pages as they may contain pointers into the old-space
3455 * which need to be scavenged. It also helps avoid unnecessary page
3456 * faults as forwarding pointers are written into them. They need to
3457 * be un-protected anyway before unmapping later. */
3458 unprotect_oldspace();
3460 /* Scavenge the stacks' conservative roots. */
3462 /* there are potentially two stacks for each thread: the main
3463 * stack, which may contain Lisp pointers, and the alternate stack.
3464 * We don't ever run Lisp code on the altstack, but it may
3465 * host a sigcontext with lisp objects in it */
3467 /* what we need to do: (1) find the stack pointer for the main
3468 * stack; scavenge it (2) find the interrupt context on the
3469 * alternate stack that might contain lisp values, and scavenge
3472 /* we assume that none of the preceding applies to the thread that
3473 * initiates GC. If you ever call GC from inside an altstack
3474 * handler, you will lose. */
3475 for_each_thread(th) {
3477 void **esp=(void **)-1;
3478 #ifdef LISP_FEATURE_SB_THREAD
3480 if(th==arch_os_get_current_thread()) {
3481 esp = (void **) &raise;
3484 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3485 for(i=free-1;i>=0;i--) {
3486 os_context_t *c=th->interrupt_contexts[i];
3487 esp1 = (void **) *os_context_register_addr(c,reg_ESP);
3488 if(esp1>=th->control_stack_start&& esp1<th->control_stack_end){
3489 if(esp1<esp) esp=esp1;
3490 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3491 preserve_pointer(*ptr);
3497 esp = (void **) &raise;
3499 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3500 preserve_pointer(*ptr);
3505 if (gencgc_verbose > 1) {
3506 int num_dont_move_pages = count_dont_move_pages();
3508 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3509 num_dont_move_pages,
3510 num_dont_move_pages * PAGE_BYTES);
3514 /* Scavenge all the rest of the roots. */
3516 /* Scavenge the Lisp functions of the interrupt handlers, taking
3517 * care to avoid SIG_DFL and SIG_IGN. */
3518 for_each_thread(th) {
3519 struct interrupt_data *data=th->interrupt_data;
3520 for (i = 0; i < NSIG; i++) {
3521 union interrupt_handler handler = data->interrupt_handlers[i];
3522 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3523 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3524 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3528 /* Scavenge the binding stacks. */
3531 for_each_thread(th) {
3532 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3533 th->binding_stack_start;
3534 scavenge((lispobj *) th->binding_stack_start,len);
3535 #ifdef LISP_FEATURE_SB_THREAD
3536 /* do the tls as well */
3537 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3538 (sizeof (struct thread))/(sizeof (lispobj));
3539 scavenge((lispobj *) (th+1),len);
3544 /* The original CMU CL code had scavenge-read-only-space code
3545 * controlled by the Lisp-level variable
3546 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3547 * wasn't documented under what circumstances it was useful or
3548 * safe to turn it on, so it's been turned off in SBCL. If you
3549 * want/need this functionality, and can test and document it,
3550 * please submit a patch. */
3552 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3553 unsigned long read_only_space_size =
3554 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3555 (lispobj*)READ_ONLY_SPACE_START;
3557 "/scavenge read only space: %d bytes\n",
3558 read_only_space_size * sizeof(lispobj)));
3559 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3563 /* Scavenge static space. */
3565 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3566 (lispobj *)STATIC_SPACE_START;
3567 if (gencgc_verbose > 1) {
3569 "/scavenge static space: %d bytes\n",
3570 static_space_size * sizeof(lispobj)));
3572 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3574 /* All generations but the generation being GCed need to be
3575 * scavenged. The new_space generation needs special handling as
3576 * objects may be moved in - it is handled separately below. */
3577 for (i = 0; i < NUM_GENERATIONS; i++) {
3578 if ((i != generation) && (i != new_space)) {
3579 scavenge_generation(i);
3583 /* Finally scavenge the new_space generation. Keep going until no
3584 * more objects are moved into the new generation */
3585 scavenge_newspace_generation(new_space);
3587 /* FIXME: I tried reenabling this check when debugging unrelated
3588 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3589 * Since the current GC code seems to work well, I'm guessing that
3590 * this debugging code is just stale, but I haven't tried to
3591 * figure it out. It should be figured out and then either made to
3592 * work or just deleted. */
3593 #define RESCAN_CHECK 0
3595 /* As a check re-scavenge the newspace once; no new objects should
3598 int old_bytes_allocated = bytes_allocated;
3599 int bytes_allocated;
3601 /* Start with a full scavenge. */
3602 scavenge_newspace_generation_one_scan(new_space);
3604 /* Flush the current regions, updating the tables. */
3605 gc_alloc_update_all_page_tables();
3607 bytes_allocated = bytes_allocated - old_bytes_allocated;
3609 if (bytes_allocated != 0) {
3610 lose("Rescan of new_space allocated %d more bytes.",
3616 scan_weak_pointers();
3618 /* Flush the current regions, updating the tables. */
3619 gc_alloc_update_all_page_tables();
3621 /* Free the pages in oldspace, but not those marked dont_move. */
3622 bytes_freed = free_oldspace();
3624 /* If the GC is not raising the age then lower the generation back
3625 * to its normal generation number */
3627 for (i = 0; i < last_free_page; i++)
3628 if ((page_table[i].bytes_used != 0)
3629 && (page_table[i].gen == NUM_GENERATIONS))
3630 page_table[i].gen = generation;
3631 gc_assert(generations[generation].bytes_allocated == 0);
3632 generations[generation].bytes_allocated =
3633 generations[NUM_GENERATIONS].bytes_allocated;
3634 generations[NUM_GENERATIONS].bytes_allocated = 0;
3637 /* Reset the alloc_start_page for generation. */
3638 generations[generation].alloc_start_page = 0;
3639 generations[generation].alloc_unboxed_start_page = 0;
3640 generations[generation].alloc_large_start_page = 0;
3641 generations[generation].alloc_large_unboxed_start_page = 0;
3643 if (generation >= verify_gens) {
3647 verify_dynamic_space();
3650 /* Set the new gc trigger for the GCed generation. */
3651 generations[generation].gc_trigger =
3652 generations[generation].bytes_allocated
3653 + generations[generation].bytes_consed_between_gc;
3656 generations[generation].num_gc = 0;
3658 ++generations[generation].num_gc;
3661 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3663 update_x86_dynamic_space_free_pointer(void)
3668 for (i = 0; i < NUM_PAGES; i++)
3669 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3670 && (page_table[i].bytes_used != 0))
3673 last_free_page = last_page+1;
3675 SetSymbolValue(ALLOCATION_POINTER,
3676 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3677 return 0; /* dummy value: return something ... */
3680 /* GC all generations newer than last_gen, raising the objects in each
3681 * to the next older generation - we finish when all generations below
3682 * last_gen are empty. Then if last_gen is due for a GC, or if
3683 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3684 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3686 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3687 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3690 collect_garbage(unsigned last_gen)
3697 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3699 if (last_gen > NUM_GENERATIONS) {
3701 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3706 /* Flush the alloc regions updating the tables. */
3707 gc_alloc_update_all_page_tables();
3709 /* Verify the new objects created by Lisp code. */
3710 if (pre_verify_gen_0) {
3711 FSHOW((stderr, "pre-checking generation 0\n"));
3712 verify_generation(0);
3715 if (gencgc_verbose > 1)
3716 print_generation_stats(0);
3719 /* Collect the generation. */
3721 if (gen >= gencgc_oldest_gen_to_gc) {
3722 /* Never raise the oldest generation. */
3727 || (generations[gen].num_gc >= generations[gen].trigger_age);
3730 if (gencgc_verbose > 1) {
3732 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3735 generations[gen].bytes_allocated,
3736 generations[gen].gc_trigger,
3737 generations[gen].num_gc));
3740 /* If an older generation is being filled, then update its
3743 generations[gen+1].cum_sum_bytes_allocated +=
3744 generations[gen+1].bytes_allocated;
3747 garbage_collect_generation(gen, raise);
3749 /* Reset the memory age cum_sum. */
3750 generations[gen].cum_sum_bytes_allocated = 0;
3752 if (gencgc_verbose > 1) {
3753 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3754 print_generation_stats(0);
3758 } while ((gen <= gencgc_oldest_gen_to_gc)
3759 && ((gen < last_gen)
3760 || ((gen <= gencgc_oldest_gen_to_gc)
3762 && (generations[gen].bytes_allocated
3763 > generations[gen].gc_trigger)
3764 && (gen_av_mem_age(gen)
3765 > generations[gen].min_av_mem_age))));
3767 /* Now if gen-1 was raised all generations before gen are empty.
3768 * If it wasn't raised then all generations before gen-1 are empty.
3770 * Now objects within this gen's pages cannot point to younger
3771 * generations unless they are written to. This can be exploited
3772 * by write-protecting the pages of gen; then when younger
3773 * generations are GCed only the pages which have been written
3778 gen_to_wp = gen - 1;
3780 /* There's not much point in WPing pages in generation 0 as it is
3781 * never scavenged (except promoted pages). */
3782 if ((gen_to_wp > 0) && enable_page_protection) {
3783 /* Check that they are all empty. */
3784 for (i = 0; i < gen_to_wp; i++) {
3785 if (generations[i].bytes_allocated)
3786 lose("trying to write-protect gen. %d when gen. %d nonempty",
3789 write_protect_generation_pages(gen_to_wp);
3792 /* Set gc_alloc() back to generation 0. The current regions should
3793 * be flushed after the above GCs. */
3794 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3795 gc_alloc_generation = 0;
3797 update_x86_dynamic_space_free_pointer();
3798 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3800 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3802 SHOW("returning from collect_garbage");
3805 /* This is called by Lisp PURIFY when it is finished. All live objects
3806 * will have been moved to the RO and Static heaps. The dynamic space
3807 * will need a full re-initialization. We don't bother having Lisp
3808 * PURIFY flush the current gc_alloc() region, as the page_tables are
3809 * re-initialized, and every page is zeroed to be sure. */
3815 if (gencgc_verbose > 1)
3816 SHOW("entering gc_free_heap");
3818 for (page = 0; page < NUM_PAGES; page++) {
3819 /* Skip free pages which should already be zero filled. */
3820 if (page_table[page].allocated != FREE_PAGE_FLAG) {
3821 void *page_start, *addr;
3823 /* Mark the page free. The other slots are assumed invalid
3824 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3825 * should not be write-protected -- except that the
3826 * generation is used for the current region but it sets
3828 page_table[page].allocated = FREE_PAGE_FLAG;
3829 page_table[page].bytes_used = 0;
3831 /* Zero the page. */
3832 page_start = (void *)page_address(page);
3834 /* First, remove any write-protection. */
3835 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3836 page_table[page].write_protected = 0;
3838 os_invalidate(page_start,PAGE_BYTES);
3839 addr = os_validate(page_start,PAGE_BYTES);
3840 if (addr == NULL || addr != page_start) {
3841 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3845 } else if (gencgc_zero_check_during_free_heap) {
3846 /* Double-check that the page is zero filled. */
3848 gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
3849 gc_assert(page_table[page].bytes_used == 0);
3850 page_start = (int *)page_address(page);
3851 for (i=0; i<1024; i++) {
3852 if (page_start[i] != 0) {
3853 lose("free region not zero at %x", page_start + i);
3859 bytes_allocated = 0;
3861 /* Initialize the generations. */
3862 for (page = 0; page < NUM_GENERATIONS; page++) {
3863 generations[page].alloc_start_page = 0;
3864 generations[page].alloc_unboxed_start_page = 0;
3865 generations[page].alloc_large_start_page = 0;
3866 generations[page].alloc_large_unboxed_start_page = 0;
3867 generations[page].bytes_allocated = 0;
3868 generations[page].gc_trigger = 2000000;
3869 generations[page].num_gc = 0;
3870 generations[page].cum_sum_bytes_allocated = 0;
3873 if (gencgc_verbose > 1)
3874 print_generation_stats(0);
3876 /* Initialize gc_alloc(). */
3877 gc_alloc_generation = 0;
3879 gc_set_region_empty(&boxed_region);
3880 gc_set_region_empty(&unboxed_region);
3883 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3885 if (verify_after_free_heap) {
3886 /* Check whether purify has left any bad pointers. */
3888 SHOW("checking after free_heap\n");
3899 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
3900 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
3901 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
3903 heap_base = (void*)DYNAMIC_SPACE_START;
3905 /* Initialize each page structure. */
3906 for (i = 0; i < NUM_PAGES; i++) {
3907 /* Initialize all pages as free. */
3908 page_table[i].allocated = FREE_PAGE_FLAG;
3909 page_table[i].bytes_used = 0;
3911 /* Pages are not write-protected at startup. */
3912 page_table[i].write_protected = 0;
3915 bytes_allocated = 0;
3917 /* Initialize the generations.
3919 * FIXME: very similar to code in gc_free_heap(), should be shared */
3920 for (i = 0; i < NUM_GENERATIONS; i++) {
3921 generations[i].alloc_start_page = 0;
3922 generations[i].alloc_unboxed_start_page = 0;
3923 generations[i].alloc_large_start_page = 0;
3924 generations[i].alloc_large_unboxed_start_page = 0;
3925 generations[i].bytes_allocated = 0;
3926 generations[i].gc_trigger = 2000000;
3927 generations[i].num_gc = 0;
3928 generations[i].cum_sum_bytes_allocated = 0;
3929 /* the tune-able parameters */
3930 generations[i].bytes_consed_between_gc = 2000000;
3931 generations[i].trigger_age = 1;
3932 generations[i].min_av_mem_age = 0.75;
3935 /* Initialize gc_alloc. */
3936 gc_alloc_generation = 0;
3937 gc_set_region_empty(&boxed_region);
3938 gc_set_region_empty(&unboxed_region);
3944 /* Pick up the dynamic space from after a core load.
3946 * The ALLOCATION_POINTER points to the end of the dynamic space.
3950 gencgc_pickup_dynamic(void)
3953 int alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
3954 lispobj *prev=(lispobj *)page_address(page);
3957 lispobj *first,*ptr= (lispobj *)page_address(page);
3958 page_table[page].allocated = BOXED_PAGE_FLAG;
3959 page_table[page].gen = 0;
3960 page_table[page].bytes_used = PAGE_BYTES;
3961 page_table[page].large_object = 0;
3963 first=search_space(prev,(ptr+2)-prev,ptr);
3964 if(ptr == first) prev=ptr;
3965 page_table[page].first_object_offset =
3966 (void *)prev - page_address(page);
3968 } while (page_address(page) < alloc_ptr);
3970 generations[0].bytes_allocated = PAGE_BYTES*page;
3971 bytes_allocated = PAGE_BYTES*page;
3977 gc_initialize_pointers(void)
3979 gencgc_pickup_dynamic();
3985 /* alloc(..) is the external interface for memory allocation. It
3986 * allocates to generation 0. It is not called from within the garbage
3987 * collector as it is only external uses that need the check for heap
3988 * size (GC trigger) and to disable the interrupts (interrupts are
3989 * always disabled during a GC).
3991 * The vops that call alloc(..) assume that the returned space is zero-filled.
3992 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
3994 * The check for a GC trigger is only performed when the current
3995 * region is full, so in most cases it's not needed. */
4000 struct thread *th=arch_os_get_current_thread();
4001 struct alloc_region *region=
4002 th ? &(th->alloc_region) : &boxed_region;
4004 void *new_free_pointer;
4006 /* Check for alignment allocation problems. */
4007 gc_assert((((unsigned)region->free_pointer & 0x7) == 0)
4008 && ((nbytes & 0x7) == 0));
4010 /* there are a few places in the C code that allocate data in the
4011 * heap before Lisp starts. This is before interrupts are enabled,
4012 * so we don't need to check for pseudo-atomic */
4013 #ifdef LISP_FEATURE_SB_THREAD
4014 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4016 fprintf(stderr, "fatal error in thread 0x%x, pid=%d\n",
4018 __asm__("movl %fs,%0" : "=r" (fs) : );
4019 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4020 debug_get_fs(),th->tls_cookie);
4021 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4024 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4027 /* maybe we can do this quickly ... */
4028 new_free_pointer = region->free_pointer + nbytes;
4029 if (new_free_pointer <= region->end_addr) {
4030 new_obj = (void*)(region->free_pointer);
4031 region->free_pointer = new_free_pointer;
4032 return(new_obj); /* yup */
4035 /* we have to go the long way around, it seems. Check whether
4036 * we should GC in the near future
4038 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4039 /* set things up so that GC happens when we finish the PA
4040 * section. We only do this if there wasn't a pending handler
4041 * already, in case it was a gc. If it wasn't a GC, the next
4042 * allocation will get us back to this point anyway, so no harm done
4044 struct interrupt_data *data=th->interrupt_data;
4045 if(!data->pending_handler)
4046 maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0);
4048 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4053 /* Find the code object for the given pc, or return NULL on failure.
4055 * FIXME: PC shouldn't be lispobj*, should it? Maybe void*? */
4057 component_ptr_from_pc(lispobj *pc)
4059 lispobj *object = NULL;
4061 if ( (object = search_read_only_space(pc)) )
4063 else if ( (object = search_static_space(pc)) )
4066 object = search_dynamic_space(pc);
4068 if (object) /* if we found something */
4069 if (widetag_of(*object) == CODE_HEADER_WIDETAG) /* if it's a code object */
4076 * shared support for the OS-dependent signal handlers which
4077 * catch GENCGC-related write-protect violations
4080 void unhandled_sigmemoryfault(void);
4082 /* Depending on which OS we're running under, different signals might
4083 * be raised for a violation of write protection in the heap. This
4084 * function factors out the common generational GC magic which needs
4085 * to invoked in this case, and should be called from whatever signal
4086 * handler is appropriate for the OS we're running under.
4088 * Return true if this signal is a normal generational GC thing that
4089 * we were able to handle, or false if it was abnormal and control
4090 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4093 gencgc_handle_wp_violation(void* fault_addr)
4095 int page_index = find_page_index(fault_addr);
4097 #if defined QSHOW_SIGNALS
4098 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4099 fault_addr, page_index));
4102 /* Check whether the fault is within the dynamic space. */
4103 if (page_index == (-1)) {
4105 /* It can be helpful to be able to put a breakpoint on this
4106 * case to help diagnose low-level problems. */
4107 unhandled_sigmemoryfault();
4109 /* not within the dynamic space -- not our responsibility */
4113 if (page_table[page_index].write_protected) {
4114 /* Unprotect the page. */
4115 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4116 page_table[page_index].write_protected_cleared = 1;
4117 page_table[page_index].write_protected = 0;
4119 /* The only acceptable reason for this signal on a heap
4120 * access is that GENCGC write-protected the page.
4121 * However, if two CPUs hit a wp page near-simultaneously,
4122 * we had better not have the second one lose here if it
4123 * does this test after the first one has already set wp=0
4125 if(page_table[page_index].write_protected_cleared != 1)
4126 lose("fault in heap page not marked as write-protected");
4128 /* Don't worry, we can handle it. */
4132 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4133 * it's not just a case of the program hitting the write barrier, and
4134 * are about to let Lisp deal with it. It's basically just a
4135 * convenient place to set a gdb breakpoint. */
4137 unhandled_sigmemoryfault()
4140 void gc_alloc_update_all_page_tables(void)
4142 /* Flush the alloc regions updating the tables. */
4145 gc_alloc_update_page_tables(0, &th->alloc_region);
4146 gc_alloc_update_page_tables(1, &unboxed_region);
4147 gc_alloc_update_page_tables(0, &boxed_region);
4150 gc_set_region_empty(struct alloc_region *region)
4152 region->first_page = 0;
4153 region->last_page = -1;
4154 region->start_addr = page_address(0);
4155 region->free_pointer = page_address(0);
4156 region->end_addr = page_address(0);