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 /* Should we unmap a page and re-mmap it to have it zero filled? */
72 #if defined(__FreeBSD__) || defined(__OpenBSD__)
73 /* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
74 * so don't unmap there.
76 * The CMU CL comment didn't specify a version, but was probably an
77 * old version of FreeBSD (pre-4.0), so this might no longer be true.
78 * OTOH, if it is true, this behavior might exist on OpenBSD too, so
79 * for now we don't unmap there either. -- WHN 2001-04-07 */
80 boolean gencgc_unmap_zero = 0;
82 boolean gencgc_unmap_zero = 1;
85 /* the minimum size (in bytes) for a large object*/
86 unsigned large_object_size = 4 * PAGE_BYTES;
95 /* the verbosity level. All non-error messages are disabled at level 0;
96 * and only a few rare messages are printed at level 1. */
97 unsigned gencgc_verbose = (QSHOW ? 1 : 0);
99 /* FIXME: At some point enable the various error-checking things below
100 * and see what they say. */
102 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
103 * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
104 int verify_gens = NUM_GENERATIONS;
106 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
107 boolean pre_verify_gen_0 = 0;
109 /* Should we check for bad pointers after gc_free_heap is called
110 * from Lisp PURIFY? */
111 boolean verify_after_free_heap = 0;
113 /* Should we print a note when code objects are found in the dynamic space
114 * during a heap verify? */
115 boolean verify_dynamic_code_check = 0;
117 /* Should we check code objects for fixup errors after they are transported? */
118 boolean check_code_fixups = 0;
120 /* Should we check that newly allocated regions are zero filled? */
121 boolean gencgc_zero_check = 0;
123 /* Should we check that the free space is zero filled? */
124 boolean gencgc_enable_verify_zero_fill = 0;
126 /* Should we check that free pages are zero filled during gc_free_heap
127 * called after Lisp PURIFY? */
128 boolean gencgc_zero_check_during_free_heap = 0;
131 * GC structures and variables
134 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
135 unsigned long bytes_allocated = 0;
136 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
137 unsigned long auto_gc_trigger = 0;
139 /* the source and destination generations. These are set before a GC starts
145 /* An array of page structures is statically allocated.
146 * This helps quickly map between an address its page structure.
147 * NUM_PAGES is set from the size of the dynamic space. */
148 struct page page_table[NUM_PAGES];
150 /* To map addresses to page structures the address of the first page
152 static void *heap_base = NULL;
155 /* Calculate the start address for the given page number. */
157 page_address(int page_num)
159 return (heap_base + (page_num * PAGE_BYTES));
162 /* Find the page index within the page_table for the given
163 * address. Return -1 on failure. */
165 find_page_index(void *addr)
167 int index = addr-heap_base;
170 index = ((unsigned int)index)/PAGE_BYTES;
171 if (index < NUM_PAGES)
178 /* a structure to hold the state of a generation */
181 /* the first page that gc_alloc() checks on its next call */
182 int alloc_start_page;
184 /* the first page that gc_alloc_unboxed() checks on its next call */
185 int alloc_unboxed_start_page;
187 /* the first page that gc_alloc_large (boxed) considers on its next
188 * call. (Although it always allocates after the boxed_region.) */
189 int alloc_large_start_page;
191 /* the first page that gc_alloc_large (unboxed) considers on its
192 * next call. (Although it always allocates after the
193 * current_unboxed_region.) */
194 int alloc_large_unboxed_start_page;
196 /* the bytes allocated to this generation */
199 /* the number of bytes at which to trigger a GC */
202 /* to calculate a new level for gc_trigger */
203 int bytes_consed_between_gc;
205 /* the number of GCs since the last raise */
208 /* the average age after which a GC will raise objects to the
212 /* the cumulative sum of the bytes allocated to this generation. It is
213 * cleared after a GC on this generations, and update before new
214 * objects are added from a GC of a younger generation. Dividing by
215 * the bytes_allocated will give the average age of the memory in
216 * this generation since its last GC. */
217 int cum_sum_bytes_allocated;
219 /* a minimum average memory age before a GC will occur helps
220 * prevent a GC when a large number of new live objects have been
221 * added, in which case a GC could be a waste of time */
222 double min_av_mem_age;
224 /* the number of actual generations. (The number of 'struct
225 * generation' objects is one more than this, because one object
226 * serves as scratch when GC'ing.) */
227 #define NUM_GENERATIONS 6
229 /* an array of generation structures. There needs to be one more
230 * generation structure than actual generations as the oldest
231 * generation is temporarily raised then lowered. */
232 struct generation generations[NUM_GENERATIONS+1];
234 /* the oldest generation that is will currently be GCed by default.
235 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
237 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
239 * Setting this to 0 effectively disables the generational nature of
240 * the GC. In some applications generational GC may not be useful
241 * because there are no long-lived objects.
243 * An intermediate value could be handy after moving long-lived data
244 * into an older generation so an unnecessary GC of this long-lived
245 * data can be avoided. */
246 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
248 /* The maximum free page in the heap is maintained and used to update
249 * ALLOCATION_POINTER which is used by the room function to limit its
250 * search of the heap. XX Gencgc obviously needs to be better
251 * integrated with the Lisp code. */
252 static int last_free_page;
254 /* This lock is to prevent multiple threads from simultaneously
255 * allocating new regions which overlap each other. Note that the
256 * majority of GC is single-threaded, but alloc() may be called from
257 * >1 thread at a time and must be thread-safe. This lock must be
258 * seized before all accesses to generations[] or to parts of
259 * page_table[] that other threads may want to see */
261 static lispobj free_pages_lock=0;
265 * miscellaneous heap functions
268 /* Count the number of pages which are write-protected within the
269 * given generation. */
271 count_write_protect_generation_pages(int generation)
276 for (i = 0; i < last_free_page; i++)
277 if ((page_table[i].allocated != FREE_PAGE)
278 && (page_table[i].gen == generation)
279 && (page_table[i].write_protected == 1))
284 /* Count the number of pages within the given generation. */
286 count_generation_pages(int generation)
291 for (i = 0; i < last_free_page; i++)
292 if ((page_table[i].allocated != 0)
293 && (page_table[i].gen == generation))
298 /* Count the number of dont_move pages. */
300 count_dont_move_pages(void)
304 for (i = 0; i < last_free_page; i++) {
305 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
312 /* Work through the pages and add up the number of bytes used for the
313 * given generation. */
315 count_generation_bytes_allocated (int gen)
319 for (i = 0; i < last_free_page; i++) {
320 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
321 result += page_table[i].bytes_used;
326 /* Return the average age of the memory in a generation. */
328 gen_av_mem_age(int gen)
330 if (generations[gen].bytes_allocated == 0)
334 ((double)generations[gen].cum_sum_bytes_allocated)
335 / ((double)generations[gen].bytes_allocated);
338 void fpu_save(int *); /* defined in x86-assem.S */
339 void fpu_restore(int *); /* defined in x86-assem.S */
340 /* The verbose argument controls how much to print: 0 for normal
341 * level of detail; 1 for debugging. */
343 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
348 /* This code uses the FP instructions which may be set up for Lisp
349 * so they need to be saved and reset for C. */
352 /* number of generations to print */
354 gens = NUM_GENERATIONS+1;
356 gens = NUM_GENERATIONS;
358 /* Print the heap stats. */
360 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
362 for (i = 0; i < gens; i++) {
366 int large_boxed_cnt = 0;
367 int large_unboxed_cnt = 0;
370 for (j = 0; j < last_free_page; j++)
371 if (page_table[j].gen == i) {
373 /* Count the number of boxed pages within the given
375 if (page_table[j].allocated & BOXED_PAGE) {
376 if (page_table[j].large_object)
381 if(page_table[j].dont_move) pinned_cnt++;
382 /* Count the number of unboxed pages within the given
384 if (page_table[j].allocated & UNBOXED_PAGE) {
385 if (page_table[j].large_object)
392 gc_assert(generations[i].bytes_allocated
393 == count_generation_bytes_allocated(i));
395 " %1d: %5d %5d %5d %5d %5d %8d %5d %8d %4d %3d %7.4f\n",
397 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
399 generations[i].bytes_allocated,
400 (count_generation_pages(i)*PAGE_BYTES
401 - generations[i].bytes_allocated),
402 generations[i].gc_trigger,
403 count_write_protect_generation_pages(i),
404 generations[i].num_gc,
407 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
409 fpu_restore(fpu_state);
413 * allocation routines
417 * To support quick and inline allocation, regions of memory can be
418 * allocated and then allocated from with just a free pointer and a
419 * check against an end address.
421 * Since objects can be allocated to spaces with different properties
422 * e.g. boxed/unboxed, generation, ages; there may need to be many
423 * allocation regions.
425 * Each allocation region may be start within a partly used page. Many
426 * features of memory use are noted on a page wise basis, e.g. the
427 * generation; so if a region starts within an existing allocated page
428 * it must be consistent with this page.
430 * During the scavenging of the newspace, objects will be transported
431 * into an allocation region, and pointers updated to point to this
432 * allocation region. It is possible that these pointers will be
433 * scavenged again before the allocation region is closed, e.g. due to
434 * trans_list which jumps all over the place to cleanup the list. It
435 * is important to be able to determine properties of all objects
436 * pointed to when scavenging, e.g to detect pointers to the oldspace.
437 * Thus it's important that the allocation regions have the correct
438 * properties set when allocated, and not just set when closed. The
439 * region allocation routines return regions with the specified
440 * properties, and grab all the pages, setting their properties
441 * appropriately, except that the amount used is not known.
443 * These regions are used to support quicker allocation using just a
444 * free pointer. The actual space used by the region is not reflected
445 * in the pages tables until it is closed. It can't be scavenged until
448 * When finished with the region it should be closed, which will
449 * update the page tables for the actual space used returning unused
450 * space. Further it may be noted in the new regions which is
451 * necessary when scavenging the newspace.
453 * Large objects may be allocated directly without an allocation
454 * region, the page tables are updated immediately.
456 * Unboxed objects don't contain pointers to other objects and so
457 * don't need scavenging. Further they can't contain pointers to
458 * younger generations so WP is not needed. By allocating pages to
459 * unboxed objects the whole page never needs scavenging or
460 * write-protecting. */
462 /* We are only using two regions at present. Both are for the current
463 * newspace generation. */
464 struct alloc_region boxed_region;
465 struct alloc_region unboxed_region;
467 /* The generation currently being allocated to. */
468 static int gc_alloc_generation;
470 /* Find a new region with room for at least the given number of bytes.
472 * It starts looking at the current generation's alloc_start_page. So
473 * may pick up from the previous region if there is enough space. This
474 * keeps the allocation contiguous when scavenging the newspace.
476 * The alloc_region should have been closed by a call to
477 * gc_alloc_update_page_tables(), and will thus be in an empty state.
479 * To assist the scavenging functions write-protected pages are not
480 * used. Free pages should not be write-protected.
482 * It is critical to the conservative GC that the start of regions be
483 * known. To help achieve this only small regions are allocated at a
486 * During scavenging, pointers may be found to within the current
487 * region and the page generation must be set so that pointers to the
488 * from space can be recognized. Therefore the generation of pages in
489 * the region are set to gc_alloc_generation. To prevent another
490 * allocation call using the same pages, all the pages in the region
491 * are allocated, although they will initially be empty.
494 gc_alloc_new_region(int nbytes, int unboxed, struct alloc_region *alloc_region)
503 "/alloc_new_region for %d bytes from gen %d\n",
504 nbytes, gc_alloc_generation));
507 /* Check that the region is in a reset state. */
508 gc_assert((alloc_region->first_page == 0)
509 && (alloc_region->last_page == -1)
510 && (alloc_region->free_pointer == alloc_region->end_addr));
511 get_spinlock(&free_pages_lock,(int) alloc_region);
514 generations[gc_alloc_generation].alloc_unboxed_start_page;
517 generations[gc_alloc_generation].alloc_start_page;
519 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
520 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
521 + PAGE_BYTES*(last_page-first_page);
523 /* Set up the alloc_region. */
524 alloc_region->first_page = first_page;
525 alloc_region->last_page = last_page;
526 alloc_region->start_addr = page_table[first_page].bytes_used
527 + page_address(first_page);
528 alloc_region->free_pointer = alloc_region->start_addr;
529 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
531 /* Set up the pages. */
533 /* The first page may have already been in use. */
534 if (page_table[first_page].bytes_used == 0) {
536 page_table[first_page].allocated = UNBOXED_PAGE;
538 page_table[first_page].allocated = BOXED_PAGE;
539 page_table[first_page].gen = gc_alloc_generation;
540 page_table[first_page].large_object = 0;
541 page_table[first_page].first_object_offset = 0;
545 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE);
547 gc_assert(page_table[first_page].allocated == BOXED_PAGE);
548 page_table[first_page].allocated |= OPEN_REGION_PAGE;
550 gc_assert(page_table[first_page].gen == gc_alloc_generation);
551 gc_assert(page_table[first_page].large_object == 0);
553 for (i = first_page+1; i <= last_page; i++) {
555 page_table[i].allocated = UNBOXED_PAGE;
557 page_table[i].allocated = BOXED_PAGE;
558 page_table[i].gen = gc_alloc_generation;
559 page_table[i].large_object = 0;
560 /* This may not be necessary for unboxed regions (think it was
562 page_table[i].first_object_offset =
563 alloc_region->start_addr - page_address(i);
564 page_table[i].allocated |= OPEN_REGION_PAGE ;
566 /* Bump up last_free_page. */
567 if (last_page+1 > last_free_page) {
568 last_free_page = last_page+1;
569 SetSymbolValue(ALLOCATION_POINTER,
570 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
573 release_spinlock(&free_pages_lock);
575 /* we can do this after releasing free_pages_lock */
576 if (gencgc_zero_check) {
578 for (p = (int *)alloc_region->start_addr;
579 p < (int *)alloc_region->end_addr; p++) {
581 /* KLUDGE: It would be nice to use %lx and explicit casts
582 * (long) in code like this, so that it is less likely to
583 * break randomly when running on a machine with different
584 * word sizes. -- WHN 19991129 */
585 lose("The new region at %x is not zero.", p);
592 /* If the record_new_objects flag is 2 then all new regions created
595 * If it's 1 then then it is only recorded if the first page of the
596 * current region is <= new_areas_ignore_page. This helps avoid
597 * unnecessary recording when doing full scavenge pass.
599 * The new_object structure holds the page, byte offset, and size of
600 * new regions of objects. Each new area is placed in the array of
601 * these structures pointer to by new_areas. new_areas_index holds the
602 * offset into new_areas.
604 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
605 * later code must detect this and handle it, probably by doing a full
606 * scavenge of a generation. */
607 #define NUM_NEW_AREAS 512
608 static int record_new_objects = 0;
609 static int new_areas_ignore_page;
615 static struct new_area (*new_areas)[];
616 static int new_areas_index;
619 /* Add a new area to new_areas. */
621 add_new_area(int first_page, int offset, int size)
623 unsigned new_area_start,c;
626 /* Ignore if full. */
627 if (new_areas_index >= NUM_NEW_AREAS)
630 switch (record_new_objects) {
634 if (first_page > new_areas_ignore_page)
643 new_area_start = PAGE_BYTES*first_page + offset;
645 /* Search backwards for a prior area that this follows from. If
646 found this will save adding a new area. */
647 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
649 PAGE_BYTES*((*new_areas)[i].page)
650 + (*new_areas)[i].offset
651 + (*new_areas)[i].size;
653 "/add_new_area S1 %d %d %d %d\n",
654 i, c, new_area_start, area_end));*/
655 if (new_area_start == area_end) {
657 "/adding to [%d] %d %d %d with %d %d %d:\n",
659 (*new_areas)[i].page,
660 (*new_areas)[i].offset,
661 (*new_areas)[i].size,
665 (*new_areas)[i].size += size;
670 (*new_areas)[new_areas_index].page = first_page;
671 (*new_areas)[new_areas_index].offset = offset;
672 (*new_areas)[new_areas_index].size = size;
674 "/new_area %d page %d offset %d size %d\n",
675 new_areas_index, first_page, offset, size));*/
678 /* Note the max new_areas used. */
679 if (new_areas_index > max_new_areas)
680 max_new_areas = new_areas_index;
683 /* Update the tables for the alloc_region. The region may be added to
686 * When done the alloc_region is set up so that the next quick alloc
687 * will fail safely and thus a new region will be allocated. Further
688 * it is safe to try to re-update the page table of this reset
691 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
697 int orig_first_page_bytes_used;
702 first_page = alloc_region->first_page;
704 /* Catch an unused alloc_region. */
705 if ((first_page == 0) && (alloc_region->last_page == -1))
708 next_page = first_page+1;
710 get_spinlock(&free_pages_lock,(int) alloc_region);
711 if (alloc_region->free_pointer != alloc_region->start_addr) {
712 /* some bytes were allocated in the region */
713 orig_first_page_bytes_used = page_table[first_page].bytes_used;
715 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
717 /* All the pages used need to be updated */
719 /* Update the first page. */
721 /* If the page was free then set up the gen, and
722 * first_object_offset. */
723 if (page_table[first_page].bytes_used == 0)
724 gc_assert(page_table[first_page].first_object_offset == 0);
725 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE);
728 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE);
730 gc_assert(page_table[first_page].allocated == BOXED_PAGE);
731 gc_assert(page_table[first_page].gen == gc_alloc_generation);
732 gc_assert(page_table[first_page].large_object == 0);
736 /* Calculate the number of bytes used in this page. This is not
737 * always the number of new bytes, unless it was free. */
739 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
740 bytes_used = PAGE_BYTES;
743 page_table[first_page].bytes_used = bytes_used;
744 byte_cnt += bytes_used;
747 /* All the rest of the pages should be free. We need to set their
748 * first_object_offset pointer to the start of the region, and set
751 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE);
753 gc_assert(page_table[next_page].allocated == UNBOXED_PAGE);
755 gc_assert(page_table[next_page].allocated == BOXED_PAGE);
756 gc_assert(page_table[next_page].bytes_used == 0);
757 gc_assert(page_table[next_page].gen == gc_alloc_generation);
758 gc_assert(page_table[next_page].large_object == 0);
760 gc_assert(page_table[next_page].first_object_offset ==
761 alloc_region->start_addr - page_address(next_page));
763 /* Calculate the number of bytes used in this page. */
765 if ((bytes_used = (alloc_region->free_pointer
766 - page_address(next_page)))>PAGE_BYTES) {
767 bytes_used = PAGE_BYTES;
770 page_table[next_page].bytes_used = bytes_used;
771 byte_cnt += bytes_used;
776 region_size = alloc_region->free_pointer - alloc_region->start_addr;
777 bytes_allocated += region_size;
778 generations[gc_alloc_generation].bytes_allocated += region_size;
780 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
782 /* Set the generations alloc restart page to the last page of
785 generations[gc_alloc_generation].alloc_unboxed_start_page =
788 generations[gc_alloc_generation].alloc_start_page = next_page-1;
790 /* Add the region to the new_areas if requested. */
792 add_new_area(first_page,orig_first_page_bytes_used, region_size);
796 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
798 gc_alloc_generation));
801 /* There are no bytes allocated. Unallocate the first_page if
802 * there are 0 bytes_used. */
803 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE);
804 if (page_table[first_page].bytes_used == 0)
805 page_table[first_page].allocated = FREE_PAGE;
808 /* Unallocate any unused pages. */
809 while (next_page <= alloc_region->last_page) {
810 gc_assert(page_table[next_page].bytes_used == 0);
811 page_table[next_page].allocated = FREE_PAGE;
814 release_spinlock(&free_pages_lock);
815 /* alloc_region is per-thread, we're ok to do this unlocked */
816 gc_set_region_empty(alloc_region);
819 static inline void *gc_quick_alloc(int nbytes);
821 /* Allocate a possibly large object. */
823 gc_alloc_large(int nbytes, int unboxed, struct alloc_region *alloc_region)
827 int orig_first_page_bytes_used;
833 get_spinlock(&free_pages_lock,(int) alloc_region);
837 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
839 first_page = generations[gc_alloc_generation].alloc_large_start_page;
841 if (first_page <= alloc_region->last_page) {
842 first_page = alloc_region->last_page+1;
845 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
847 gc_assert(first_page > alloc_region->last_page);
849 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
852 generations[gc_alloc_generation].alloc_large_start_page = last_page;
854 /* Set up the pages. */
855 orig_first_page_bytes_used = page_table[first_page].bytes_used;
857 /* If the first page was free then set up the gen, and
858 * first_object_offset. */
859 if (page_table[first_page].bytes_used == 0) {
861 page_table[first_page].allocated = UNBOXED_PAGE;
863 page_table[first_page].allocated = BOXED_PAGE;
864 page_table[first_page].gen = gc_alloc_generation;
865 page_table[first_page].first_object_offset = 0;
866 page_table[first_page].large_object = 1;
870 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE);
872 gc_assert(page_table[first_page].allocated == BOXED_PAGE);
873 gc_assert(page_table[first_page].gen == gc_alloc_generation);
874 gc_assert(page_table[first_page].large_object == 1);
878 /* Calc. the number of bytes used in this page. This is not
879 * always the number of new bytes, unless it was free. */
881 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
882 bytes_used = PAGE_BYTES;
885 page_table[first_page].bytes_used = bytes_used;
886 byte_cnt += bytes_used;
888 next_page = first_page+1;
890 /* All the rest of the pages should be free. We need to set their
891 * first_object_offset pointer to the start of the region, and
892 * set the bytes_used. */
894 gc_assert(page_table[next_page].allocated == FREE_PAGE);
895 gc_assert(page_table[next_page].bytes_used == 0);
897 page_table[next_page].allocated = UNBOXED_PAGE;
899 page_table[next_page].allocated = BOXED_PAGE;
900 page_table[next_page].gen = gc_alloc_generation;
901 page_table[next_page].large_object = 1;
903 page_table[next_page].first_object_offset =
904 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
906 /* Calculate the number of bytes used in this page. */
908 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
909 bytes_used = PAGE_BYTES;
912 page_table[next_page].bytes_used = bytes_used;
913 page_table[next_page].write_protected=0;
914 page_table[next_page].dont_move=0;
915 byte_cnt += bytes_used;
919 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
921 bytes_allocated += nbytes;
922 generations[gc_alloc_generation].bytes_allocated += nbytes;
924 /* Add the region to the new_areas if requested. */
926 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
928 /* Bump up last_free_page */
929 if (last_page+1 > last_free_page) {
930 last_free_page = last_page+1;
931 SetSymbolValue(ALLOCATION_POINTER,
932 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
934 release_spinlock(&free_pages_lock);
936 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
940 gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed)
945 int restart_page=*restart_page_ptr;
948 int large_p=(nbytes>=large_object_size);
949 gc_assert(free_pages_lock);
951 /* Search for a contiguous free space of at least nbytes. If it's
952 * a large object then align it on a page boundary by searching
953 * for a free page. */
956 first_page = restart_page;
958 while ((first_page < NUM_PAGES)
959 && (page_table[first_page].allocated != FREE_PAGE))
962 while (first_page < NUM_PAGES) {
963 if(page_table[first_page].allocated == FREE_PAGE)
965 if((page_table[first_page].allocated ==
966 (unboxed ? UNBOXED_PAGE : BOXED_PAGE)) &&
967 (page_table[first_page].large_object == 0) &&
968 (page_table[first_page].gen == gc_alloc_generation) &&
969 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
970 (page_table[first_page].write_protected == 0) &&
971 (page_table[first_page].dont_move == 0)) {
977 if (first_page >= NUM_PAGES) {
979 "Argh! gc_find_free_space failed (first_page), nbytes=%d.\n",
981 print_generation_stats(1);
985 gc_assert(page_table[first_page].write_protected == 0);
987 last_page = first_page;
988 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
990 while (((bytes_found < nbytes)
991 || (!large_p && (num_pages < 2)))
992 && (last_page < (NUM_PAGES-1))
993 && (page_table[last_page+1].allocated == FREE_PAGE)) {
996 bytes_found += PAGE_BYTES;
997 gc_assert(page_table[last_page].write_protected == 0);
1000 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
1001 + PAGE_BYTES*(last_page-first_page);
1003 gc_assert(bytes_found == region_size);
1004 restart_page = last_page + 1;
1005 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
1007 /* Check for a failure */
1008 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
1010 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%d.\n",
1012 print_generation_stats(1);
1015 *restart_page_ptr=first_page;
1019 /* Allocate bytes. All the rest of the special-purpose allocation
1020 * functions will eventually call this */
1023 gc_alloc_with_region(int nbytes,int unboxed_p, struct alloc_region *my_region,
1026 void *new_free_pointer;
1028 if(nbytes>=large_object_size)
1029 return gc_alloc_large(nbytes,unboxed_p,my_region);
1031 /* Check whether there is room in the current alloc region. */
1032 new_free_pointer = my_region->free_pointer + nbytes;
1034 if (new_free_pointer <= my_region->end_addr) {
1035 /* If so then allocate from the current alloc region. */
1036 void *new_obj = my_region->free_pointer;
1037 my_region->free_pointer = new_free_pointer;
1039 /* Unless a `quick' alloc was requested, check whether the
1040 alloc region is almost empty. */
1042 (my_region->end_addr - my_region->free_pointer) <= 32) {
1043 /* If so, finished with the current region. */
1044 gc_alloc_update_page_tables(unboxed_p, my_region);
1045 /* Set up a new region. */
1046 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1049 return((void *)new_obj);
1052 /* Else not enough free space in the current region: retry with a
1055 gc_alloc_update_page_tables(unboxed_p, my_region);
1056 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1057 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1060 /* these are only used during GC: all allocation from the mutator calls
1061 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1065 gc_general_alloc(int nbytes,int unboxed_p,int quick_p)
1067 struct alloc_region *my_region =
1068 unboxed_p ? &unboxed_region : &boxed_region;
1069 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1072 static inline void *
1073 gc_quick_alloc(int nbytes)
1075 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1078 static inline void *
1079 gc_quick_alloc_large(int nbytes)
1081 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1084 static inline void *
1085 gc_alloc_unboxed(int nbytes)
1087 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1090 static inline void *
1091 gc_quick_alloc_unboxed(int nbytes)
1093 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1096 static inline void *
1097 gc_quick_alloc_large_unboxed(int nbytes)
1099 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1103 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1106 extern int (*scavtab[256])(lispobj *where, lispobj object);
1107 extern lispobj (*transother[256])(lispobj object);
1108 extern int (*sizetab[256])(lispobj *where);
1110 /* Copy a large boxed object. If the object is in a large object
1111 * region then it is simply promoted, else it is copied. If it's large
1112 * enough then it's copied to a large object region.
1114 * Vectors may have shrunk. If the object is not copied the space
1115 * needs to be reclaimed, and the page_tables corrected. */
1117 copy_large_object(lispobj object, int nwords)
1123 gc_assert(is_lisp_pointer(object));
1124 gc_assert(from_space_p(object));
1125 gc_assert((nwords & 0x01) == 0);
1128 /* Check whether it's in a large object region. */
1129 first_page = find_page_index((void *)object);
1130 gc_assert(first_page >= 0);
1132 if (page_table[first_page].large_object) {
1134 /* Promote the object. */
1136 int remaining_bytes;
1141 /* Note: Any page write-protection must be removed, else a
1142 * later scavenge_newspace may incorrectly not scavenge these
1143 * pages. This would not be necessary if they are added to the
1144 * new areas, but let's do it for them all (they'll probably
1145 * be written anyway?). */
1147 gc_assert(page_table[first_page].first_object_offset == 0);
1149 next_page = first_page;
1150 remaining_bytes = nwords*4;
1151 while (remaining_bytes > PAGE_BYTES) {
1152 gc_assert(page_table[next_page].gen == from_space);
1153 gc_assert(page_table[next_page].allocated == BOXED_PAGE);
1154 gc_assert(page_table[next_page].large_object);
1155 gc_assert(page_table[next_page].first_object_offset==
1156 -PAGE_BYTES*(next_page-first_page));
1157 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1159 page_table[next_page].gen = new_space;
1161 /* Remove any write-protection. We should be able to rely
1162 * on the write-protect flag to avoid redundant calls. */
1163 if (page_table[next_page].write_protected) {
1164 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1165 page_table[next_page].write_protected = 0;
1167 remaining_bytes -= PAGE_BYTES;
1171 /* Now only one page remains, but the object may have shrunk
1172 * so there may be more unused pages which will be freed. */
1174 /* The object may have shrunk but shouldn't have grown. */
1175 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1177 page_table[next_page].gen = new_space;
1178 gc_assert(page_table[next_page].allocated == BOXED_PAGE);
1180 /* Adjust the bytes_used. */
1181 old_bytes_used = page_table[next_page].bytes_used;
1182 page_table[next_page].bytes_used = remaining_bytes;
1184 bytes_freed = old_bytes_used - remaining_bytes;
1186 /* Free any remaining pages; needs care. */
1188 while ((old_bytes_used == PAGE_BYTES) &&
1189 (page_table[next_page].gen == from_space) &&
1190 (page_table[next_page].allocated == BOXED_PAGE) &&
1191 page_table[next_page].large_object &&
1192 (page_table[next_page].first_object_offset ==
1193 -(next_page - first_page)*PAGE_BYTES)) {
1194 /* Checks out OK, free the page. Don't need to bother zeroing
1195 * pages as this should have been done before shrinking the
1196 * object. These pages shouldn't be write-protected as they
1197 * should be zero filled. */
1198 gc_assert(page_table[next_page].write_protected == 0);
1200 old_bytes_used = page_table[next_page].bytes_used;
1201 page_table[next_page].allocated = FREE_PAGE;
1202 page_table[next_page].bytes_used = 0;
1203 bytes_freed += old_bytes_used;
1207 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1208 generations[new_space].bytes_allocated += 4*nwords;
1209 bytes_allocated -= bytes_freed;
1211 /* Add the region to the new_areas if requested. */
1212 add_new_area(first_page,0,nwords*4);
1216 /* Get tag of object. */
1217 tag = lowtag_of(object);
1219 /* Allocate space. */
1220 new = gc_quick_alloc_large(nwords*4);
1222 memcpy(new,native_pointer(object),nwords*4);
1224 /* Return Lisp pointer of new object. */
1225 return ((lispobj) new) | tag;
1229 /* to copy unboxed objects */
1231 copy_unboxed_object(lispobj object, int nwords)
1236 gc_assert(is_lisp_pointer(object));
1237 gc_assert(from_space_p(object));
1238 gc_assert((nwords & 0x01) == 0);
1240 /* Get tag of object. */
1241 tag = lowtag_of(object);
1243 /* Allocate space. */
1244 new = gc_quick_alloc_unboxed(nwords*4);
1246 memcpy(new,native_pointer(object),nwords*4);
1248 /* Return Lisp pointer of new object. */
1249 return ((lispobj) new) | tag;
1252 /* to copy large unboxed objects
1254 * If the object is in a large object region then it is simply
1255 * promoted, else it is copied. If it's large enough then it's copied
1256 * to a large object region.
1258 * Bignums and vectors may have shrunk. If the object is not copied
1259 * the space needs to be reclaimed, and the page_tables corrected.
1261 * KLUDGE: There's a lot of cut-and-paste duplication between this
1262 * function and copy_large_object(..). -- WHN 20000619 */
1264 copy_large_unboxed_object(lispobj object, int nwords)
1268 lispobj *source, *dest;
1271 gc_assert(is_lisp_pointer(object));
1272 gc_assert(from_space_p(object));
1273 gc_assert((nwords & 0x01) == 0);
1275 if ((nwords > 1024*1024) && gencgc_verbose)
1276 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*4));
1278 /* Check whether it's a large object. */
1279 first_page = find_page_index((void *)object);
1280 gc_assert(first_page >= 0);
1282 if (page_table[first_page].large_object) {
1283 /* Promote the object. Note: Unboxed objects may have been
1284 * allocated to a BOXED region so it may be necessary to
1285 * change the region to UNBOXED. */
1286 int remaining_bytes;
1291 gc_assert(page_table[first_page].first_object_offset == 0);
1293 next_page = first_page;
1294 remaining_bytes = nwords*4;
1295 while (remaining_bytes > PAGE_BYTES) {
1296 gc_assert(page_table[next_page].gen == from_space);
1297 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE)
1298 || (page_table[next_page].allocated == BOXED_PAGE));
1299 gc_assert(page_table[next_page].large_object);
1300 gc_assert(page_table[next_page].first_object_offset==
1301 -PAGE_BYTES*(next_page-first_page));
1302 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1304 page_table[next_page].gen = new_space;
1305 page_table[next_page].allocated = UNBOXED_PAGE;
1306 remaining_bytes -= PAGE_BYTES;
1310 /* Now only one page remains, but the object may have shrunk so
1311 * there may be more unused pages which will be freed. */
1313 /* Object may have shrunk but shouldn't have grown - check. */
1314 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1316 page_table[next_page].gen = new_space;
1317 page_table[next_page].allocated = UNBOXED_PAGE;
1319 /* Adjust the bytes_used. */
1320 old_bytes_used = page_table[next_page].bytes_used;
1321 page_table[next_page].bytes_used = remaining_bytes;
1323 bytes_freed = old_bytes_used - remaining_bytes;
1325 /* Free any remaining pages; needs care. */
1327 while ((old_bytes_used == PAGE_BYTES) &&
1328 (page_table[next_page].gen == from_space) &&
1329 ((page_table[next_page].allocated == UNBOXED_PAGE)
1330 || (page_table[next_page].allocated == BOXED_PAGE)) &&
1331 page_table[next_page].large_object &&
1332 (page_table[next_page].first_object_offset ==
1333 -(next_page - first_page)*PAGE_BYTES)) {
1334 /* Checks out OK, free the page. Don't need to both zeroing
1335 * pages as this should have been done before shrinking the
1336 * object. These pages shouldn't be write-protected, even if
1337 * boxed they should be zero filled. */
1338 gc_assert(page_table[next_page].write_protected == 0);
1340 old_bytes_used = page_table[next_page].bytes_used;
1341 page_table[next_page].allocated = FREE_PAGE;
1342 page_table[next_page].bytes_used = 0;
1343 bytes_freed += old_bytes_used;
1347 if ((bytes_freed > 0) && gencgc_verbose)
1349 "/copy_large_unboxed bytes_freed=%d\n",
1352 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1353 generations[new_space].bytes_allocated += 4*nwords;
1354 bytes_allocated -= bytes_freed;
1359 /* Get tag of object. */
1360 tag = lowtag_of(object);
1362 /* Allocate space. */
1363 new = gc_quick_alloc_large_unboxed(nwords*4);
1366 source = (lispobj *) native_pointer(object);
1368 /* Copy the object. */
1369 while (nwords > 0) {
1370 dest[0] = source[0];
1371 dest[1] = source[1];
1377 /* Return Lisp pointer of new object. */
1378 return ((lispobj) new) | tag;
1387 * code and code-related objects
1390 static lispobj trans_fun_header(lispobj object);
1391 static lispobj trans_boxed(lispobj object);
1394 /* Scan a x86 compiled code object, looking for possible fixups that
1395 * have been missed after a move.
1397 * Two types of fixups are needed:
1398 * 1. Absolute fixups to within the code object.
1399 * 2. Relative fixups to outside the code object.
1401 * Currently only absolute fixups to the constant vector, or to the
1402 * code area are checked. */
1404 sniff_code_object(struct code *code, unsigned displacement)
1406 int nheader_words, ncode_words, nwords;
1408 void *constants_start_addr, *constants_end_addr;
1409 void *code_start_addr, *code_end_addr;
1410 int fixup_found = 0;
1412 if (!check_code_fixups)
1415 ncode_words = fixnum_value(code->code_size);
1416 nheader_words = HeaderValue(*(lispobj *)code);
1417 nwords = ncode_words + nheader_words;
1419 constants_start_addr = (void *)code + 5*4;
1420 constants_end_addr = (void *)code + nheader_words*4;
1421 code_start_addr = (void *)code + nheader_words*4;
1422 code_end_addr = (void *)code + nwords*4;
1424 /* Work through the unboxed code. */
1425 for (p = code_start_addr; p < code_end_addr; p++) {
1426 void *data = *(void **)p;
1427 unsigned d1 = *((unsigned char *)p - 1);
1428 unsigned d2 = *((unsigned char *)p - 2);
1429 unsigned d3 = *((unsigned char *)p - 3);
1430 unsigned d4 = *((unsigned char *)p - 4);
1432 unsigned d5 = *((unsigned char *)p - 5);
1433 unsigned d6 = *((unsigned char *)p - 6);
1436 /* Check for code references. */
1437 /* Check for a 32 bit word that looks like an absolute
1438 reference to within the code adea of the code object. */
1439 if ((data >= (code_start_addr-displacement))
1440 && (data < (code_end_addr-displacement))) {
1441 /* function header */
1443 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) == (unsigned)code)) {
1444 /* Skip the function header */
1448 /* the case of PUSH imm32 */
1452 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1453 p, d6, d5, d4, d3, d2, d1, data));
1454 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1456 /* the case of MOV [reg-8],imm32 */
1458 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1459 || d2==0x45 || d2==0x46 || d2==0x47)
1463 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1464 p, d6, d5, d4, d3, d2, d1, data));
1465 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1467 /* the case of LEA reg,[disp32] */
1468 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1471 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1472 p, d6, d5, d4, d3, d2, d1, data));
1473 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1477 /* Check for constant references. */
1478 /* Check for a 32 bit word that looks like an absolute
1479 reference to within the constant vector. Constant references
1481 if ((data >= (constants_start_addr-displacement))
1482 && (data < (constants_end_addr-displacement))
1483 && (((unsigned)data & 0x3) == 0)) {
1488 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1489 p, d6, d5, d4, d3, d2, d1, data));
1490 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1493 /* the case of MOV m32,EAX */
1497 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1498 p, d6, d5, d4, d3, d2, d1, data));
1499 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1502 /* the case of CMP m32,imm32 */
1503 if ((d1 == 0x3d) && (d2 == 0x81)) {
1506 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1507 p, d6, d5, d4, d3, d2, d1, data));
1509 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1512 /* Check for a mod=00, r/m=101 byte. */
1513 if ((d1 & 0xc7) == 5) {
1518 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1519 p, d6, d5, d4, d3, d2, d1, data));
1520 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1522 /* the case of CMP reg32,m32 */
1526 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1527 p, d6, d5, d4, d3, d2, d1, data));
1528 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1530 /* the case of MOV m32,reg32 */
1534 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1535 p, d6, d5, d4, d3, d2, d1, data));
1536 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1538 /* the case of MOV reg32,m32 */
1542 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1543 p, d6, d5, d4, d3, d2, d1, data));
1544 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1546 /* the case of LEA reg32,m32 */
1550 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1551 p, d6, d5, d4, d3, d2, d1, data));
1552 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1558 /* If anything was found, print some information on the code
1562 "/compiled code object at %x: header words = %d, code words = %d\n",
1563 code, nheader_words, ncode_words));
1565 "/const start = %x, end = %x\n",
1566 constants_start_addr, constants_end_addr));
1568 "/code start = %x, end = %x\n",
1569 code_start_addr, code_end_addr));
1574 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1576 int nheader_words, ncode_words, nwords;
1577 void *constants_start_addr, *constants_end_addr;
1578 void *code_start_addr, *code_end_addr;
1579 lispobj fixups = NIL;
1580 unsigned displacement = (unsigned)new_code - (unsigned)old_code;
1581 struct vector *fixups_vector;
1583 ncode_words = fixnum_value(new_code->code_size);
1584 nheader_words = HeaderValue(*(lispobj *)new_code);
1585 nwords = ncode_words + nheader_words;
1587 "/compiled code object at %x: header words = %d, code words = %d\n",
1588 new_code, nheader_words, ncode_words)); */
1589 constants_start_addr = (void *)new_code + 5*4;
1590 constants_end_addr = (void *)new_code + nheader_words*4;
1591 code_start_addr = (void *)new_code + nheader_words*4;
1592 code_end_addr = (void *)new_code + nwords*4;
1595 "/const start = %x, end = %x\n",
1596 constants_start_addr,constants_end_addr));
1598 "/code start = %x; end = %x\n",
1599 code_start_addr,code_end_addr));
1602 /* The first constant should be a pointer to the fixups for this
1603 code objects. Check. */
1604 fixups = new_code->constants[0];
1606 /* It will be 0 or the unbound-marker if there are no fixups (as
1607 * will be the case if the code object has been purified, for
1608 * example) and will be an other pointer if it is valid. */
1609 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1610 !is_lisp_pointer(fixups)) {
1611 /* Check for possible errors. */
1612 if (check_code_fixups)
1613 sniff_code_object(new_code, displacement);
1618 fixups_vector = (struct vector *)native_pointer(fixups);
1620 /* Could be pointing to a forwarding pointer. */
1621 /* FIXME is this always in from_space? if so, could replace this code with
1622 * forwarding_pointer_p/forwarding_pointer_value */
1623 if (is_lisp_pointer(fixups) &&
1624 (find_page_index((void*)fixups_vector) != -1) &&
1625 (fixups_vector->header == 0x01)) {
1626 /* If so, then follow it. */
1627 /*SHOW("following pointer to a forwarding pointer");*/
1628 fixups_vector = (struct vector *)native_pointer((lispobj)fixups_vector->length);
1631 /*SHOW("got fixups");*/
1633 if (widetag_of(fixups_vector->header) ==
1634 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
1635 /* Got the fixups for the code block. Now work through the vector,
1636 and apply a fixup at each address. */
1637 int length = fixnum_value(fixups_vector->length);
1639 for (i = 0; i < length; i++) {
1640 unsigned offset = fixups_vector->data[i];
1641 /* Now check the current value of offset. */
1642 unsigned old_value =
1643 *(unsigned *)((unsigned)code_start_addr + offset);
1645 /* If it's within the old_code object then it must be an
1646 * absolute fixup (relative ones are not saved) */
1647 if ((old_value >= (unsigned)old_code)
1648 && (old_value < ((unsigned)old_code + nwords*4)))
1649 /* So add the dispacement. */
1650 *(unsigned *)((unsigned)code_start_addr + offset) =
1651 old_value + displacement;
1653 /* It is outside the old code object so it must be a
1654 * relative fixup (absolute fixups are not saved). So
1655 * subtract the displacement. */
1656 *(unsigned *)((unsigned)code_start_addr + offset) =
1657 old_value - displacement;
1661 /* Check for possible errors. */
1662 if (check_code_fixups) {
1663 sniff_code_object(new_code,displacement);
1669 trans_boxed_large(lispobj object)
1672 unsigned long length;
1674 gc_assert(is_lisp_pointer(object));
1676 header = *((lispobj *) native_pointer(object));
1677 length = HeaderValue(header) + 1;
1678 length = CEILING(length, 2);
1680 return copy_large_object(object, length);
1685 trans_unboxed_large(lispobj object)
1688 unsigned long length;
1691 gc_assert(is_lisp_pointer(object));
1693 header = *((lispobj *) native_pointer(object));
1694 length = HeaderValue(header) + 1;
1695 length = CEILING(length, 2);
1697 return copy_large_unboxed_object(object, length);
1702 * vector-like objects
1706 /* FIXME: What does this mean? */
1707 int gencgc_hash = 1;
1710 scav_vector(lispobj *where, lispobj object)
1712 unsigned int kv_length;
1714 unsigned int length = 0; /* (0 = dummy to stop GCC warning) */
1715 lispobj *hash_table;
1716 lispobj empty_symbol;
1717 unsigned int *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1718 unsigned int *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1719 unsigned int *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1721 unsigned next_vector_length = 0;
1723 /* FIXME: A comment explaining this would be nice. It looks as
1724 * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
1725 * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
1726 if (HeaderValue(object) != subtype_VectorValidHashing)
1730 /* This is set for backward compatibility. FIXME: Do we need
1733 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
1737 kv_length = fixnum_value(where[1]);
1738 kv_vector = where + 2; /* Skip the header and length. */
1739 /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
1741 /* Scavenge element 0, which may be a hash-table structure. */
1742 scavenge(where+2, 1);
1743 if (!is_lisp_pointer(where[2])) {
1744 lose("no pointer at %x in hash table", where[2]);
1746 hash_table = (lispobj *)native_pointer(where[2]);
1747 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1748 if (widetag_of(hash_table[0]) != INSTANCE_HEADER_WIDETAG) {
1749 lose("hash table not instance (%x at %x)", hash_table[0], hash_table);
1752 /* Scavenge element 1, which should be some internal symbol that
1753 * the hash table code reserves for marking empty slots. */
1754 scavenge(where+3, 1);
1755 if (!is_lisp_pointer(where[3])) {
1756 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1758 empty_symbol = where[3];
1759 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1760 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1761 SYMBOL_HEADER_WIDETAG) {
1762 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1763 *(lispobj *)native_pointer(empty_symbol));
1766 /* Scavenge hash table, which will fix the positions of the other
1767 * needed objects. */
1768 scavenge(hash_table, 16);
1770 /* Cross-check the kv_vector. */
1771 if (where != (lispobj *)native_pointer(hash_table[9])) {
1772 lose("hash_table table!=this table %x", hash_table[9]);
1776 weak_p_obj = hash_table[10];
1780 lispobj index_vector_obj = hash_table[13];
1782 if (is_lisp_pointer(index_vector_obj) &&
1783 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1784 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1785 index_vector = ((unsigned int *)native_pointer(index_vector_obj)) + 2;
1786 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1787 length = fixnum_value(((unsigned int *)native_pointer(index_vector_obj))[1]);
1788 /*FSHOW((stderr, "/length = %d\n", length));*/
1790 lose("invalid index_vector %x", index_vector_obj);
1796 lispobj next_vector_obj = hash_table[14];
1798 if (is_lisp_pointer(next_vector_obj) &&
1799 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1800 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1801 next_vector = ((unsigned int *)native_pointer(next_vector_obj)) + 2;
1802 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1803 next_vector_length = fixnum_value(((unsigned int *)native_pointer(next_vector_obj))[1]);
1804 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1806 lose("invalid next_vector %x", next_vector_obj);
1810 /* maybe hash vector */
1812 /* FIXME: This bare "15" offset should become a symbolic
1813 * expression of some sort. And all the other bare offsets
1814 * too. And the bare "16" in scavenge(hash_table, 16). And
1815 * probably other stuff too. Ugh.. */
1816 lispobj hash_vector_obj = hash_table[15];
1818 if (is_lisp_pointer(hash_vector_obj) &&
1819 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj))
1820 == SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1821 hash_vector = ((unsigned int *)native_pointer(hash_vector_obj)) + 2;
1822 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1823 gc_assert(fixnum_value(((unsigned int *)native_pointer(hash_vector_obj))[1])
1824 == next_vector_length);
1827 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1831 /* These lengths could be different as the index_vector can be a
1832 * different length from the others, a larger index_vector could help
1833 * reduce collisions. */
1834 gc_assert(next_vector_length*2 == kv_length);
1836 /* now all set up.. */
1838 /* Work through the KV vector. */
1841 for (i = 1; i < next_vector_length; i++) {
1842 lispobj old_key = kv_vector[2*i];
1843 unsigned int old_index = (old_key & 0x1fffffff)%length;
1845 /* Scavenge the key and value. */
1846 scavenge(&kv_vector[2*i],2);
1848 /* Check whether the key has moved and is EQ based. */
1850 lispobj new_key = kv_vector[2*i];
1851 unsigned int new_index = (new_key & 0x1fffffff)%length;
1853 if ((old_index != new_index) &&
1854 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1855 ((new_key != empty_symbol) ||
1856 (kv_vector[2*i] != empty_symbol))) {
1859 "* EQ key %d moved from %x to %x; index %d to %d\n",
1860 i, old_key, new_key, old_index, new_index));*/
1862 if (index_vector[old_index] != 0) {
1863 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1865 /* Unlink the key from the old_index chain. */
1866 if (index_vector[old_index] == i) {
1867 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1868 index_vector[old_index] = next_vector[i];
1869 /* Link it into the needing rehash chain. */
1870 next_vector[i] = fixnum_value(hash_table[11]);
1871 hash_table[11] = make_fixnum(i);
1874 unsigned prior = index_vector[old_index];
1875 unsigned next = next_vector[prior];
1877 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1880 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1883 next_vector[prior] = next_vector[next];
1884 /* Link it into the needing rehash
1887 fixnum_value(hash_table[11]);
1888 hash_table[11] = make_fixnum(next);
1893 next = next_vector[next];
1901 return (CEILING(kv_length + 2, 2));
1910 /* XX This is a hack adapted from cgc.c. These don't work too
1911 * efficiently with the gencgc as a list of the weak pointers is
1912 * maintained within the objects which causes writes to the pages. A
1913 * limited attempt is made to avoid unnecessary writes, but this needs
1915 #define WEAK_POINTER_NWORDS \
1916 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1919 scav_weak_pointer(lispobj *where, lispobj object)
1921 struct weak_pointer *wp = weak_pointers;
1922 /* Push the weak pointer onto the list of weak pointers.
1923 * Do I have to watch for duplicates? Originally this was
1924 * part of trans_weak_pointer but that didn't work in the
1925 * case where the WP was in a promoted region.
1928 /* Check whether it's already in the list. */
1929 while (wp != NULL) {
1930 if (wp == (struct weak_pointer*)where) {
1936 /* Add it to the start of the list. */
1937 wp = (struct weak_pointer*)where;
1938 if (wp->next != weak_pointers) {
1939 wp->next = weak_pointers;
1941 /*SHOW("avoided write to weak pointer");*/
1946 /* Do not let GC scavenge the value slot of the weak pointer.
1947 * (That is why it is a weak pointer.) */
1949 return WEAK_POINTER_NWORDS;
1953 /* Scan an area looking for an object which encloses the given pointer.
1954 * Return the object start on success or NULL on failure. */
1956 search_space(lispobj *start, size_t words, lispobj *pointer)
1960 lispobj thing = *start;
1962 /* If thing is an immediate then this is a cons. */
1963 if (is_lisp_pointer(thing)
1964 || ((thing & 3) == 0) /* fixnum */
1965 || (widetag_of(thing) == BASE_CHAR_WIDETAG)
1966 || (widetag_of(thing) == UNBOUND_MARKER_WIDETAG))
1969 count = (sizetab[widetag_of(thing)])(start);
1971 /* Check whether the pointer is within this object. */
1972 if ((pointer >= start) && (pointer < (start+count))) {
1974 /*FSHOW((stderr,"/found %x in %x %x\n", pointer, start, thing));*/
1978 /* Round up the count. */
1979 count = CEILING(count,2);
1988 search_read_only_space(lispobj *pointer)
1990 lispobj* start = (lispobj*)READ_ONLY_SPACE_START;
1991 lispobj* end = (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1992 if ((pointer < start) || (pointer >= end))
1994 return (search_space(start, (pointer+2)-start, pointer));
1998 search_static_space(lispobj *pointer)
2000 lispobj* start = (lispobj*)STATIC_SPACE_START;
2001 lispobj* end = (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
2002 if ((pointer < start) || (pointer >= end))
2004 return (search_space(start, (pointer+2)-start, pointer));
2007 /* a faster version for searching the dynamic space. This will work even
2008 * if the object is in a current allocation region. */
2010 search_dynamic_space(lispobj *pointer)
2012 int page_index = find_page_index(pointer);
2015 /* The address may be invalid, so do some checks. */
2016 if ((page_index == -1) || (page_table[page_index].allocated == FREE_PAGE))
2018 start = (lispobj *)((void *)page_address(page_index)
2019 + page_table[page_index].first_object_offset);
2020 return (search_space(start, (pointer+2)-start, pointer));
2023 /* Is there any possibility that pointer is a valid Lisp object
2024 * reference, and/or something else (e.g. subroutine call return
2025 * address) which should prevent us from moving the referred-to thing?
2026 * This is called from preserve_pointers() */
2028 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2030 lispobj *start_addr;
2032 /* Find the object start address. */
2033 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2037 /* We need to allow raw pointers into Code objects for return
2038 * addresses. This will also pick up pointers to functions in code
2040 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2041 /* XXX could do some further checks here */
2045 /* If it's not a return address then it needs to be a valid Lisp
2047 if (!is_lisp_pointer((lispobj)pointer)) {
2051 /* Check that the object pointed to is consistent with the pointer
2054 switch (lowtag_of((lispobj)pointer)) {
2055 case FUN_POINTER_LOWTAG:
2056 /* Start_addr should be the enclosing code object, or a closure
2058 switch (widetag_of(*start_addr)) {
2059 case CODE_HEADER_WIDETAG:
2060 /* This case is probably caught above. */
2062 case CLOSURE_HEADER_WIDETAG:
2063 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2064 if ((unsigned)pointer !=
2065 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2069 pointer, start_addr, *start_addr));
2077 pointer, start_addr, *start_addr));
2081 case LIST_POINTER_LOWTAG:
2082 if ((unsigned)pointer !=
2083 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2087 pointer, start_addr, *start_addr));
2090 /* Is it plausible cons? */
2091 if ((is_lisp_pointer(start_addr[0])
2092 || ((start_addr[0] & 3) == 0) /* fixnum */
2093 || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
2094 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2095 && (is_lisp_pointer(start_addr[1])
2096 || ((start_addr[1] & 3) == 0) /* fixnum */
2097 || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
2098 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2104 pointer, start_addr, *start_addr));
2107 case INSTANCE_POINTER_LOWTAG:
2108 if ((unsigned)pointer !=
2109 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2113 pointer, start_addr, *start_addr));
2116 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2120 pointer, start_addr, *start_addr));
2124 case OTHER_POINTER_LOWTAG:
2125 if ((unsigned)pointer !=
2126 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2130 pointer, start_addr, *start_addr));
2133 /* Is it plausible? Not a cons. XXX should check the headers. */
2134 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2138 pointer, start_addr, *start_addr));
2141 switch (widetag_of(start_addr[0])) {
2142 case UNBOUND_MARKER_WIDETAG:
2143 case BASE_CHAR_WIDETAG:
2147 pointer, start_addr, *start_addr));
2150 /* only pointed to by function pointers? */
2151 case CLOSURE_HEADER_WIDETAG:
2152 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2156 pointer, start_addr, *start_addr));
2159 case INSTANCE_HEADER_WIDETAG:
2163 pointer, start_addr, *start_addr));
2166 /* the valid other immediate pointer objects */
2167 case SIMPLE_VECTOR_WIDETAG:
2169 case COMPLEX_WIDETAG:
2170 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2171 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2173 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2174 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2176 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2177 case COMPLEX_LONG_FLOAT_WIDETAG:
2179 case SIMPLE_ARRAY_WIDETAG:
2180 case COMPLEX_BASE_STRING_WIDETAG:
2181 case COMPLEX_VECTOR_NIL_WIDETAG:
2182 case COMPLEX_BIT_VECTOR_WIDETAG:
2183 case COMPLEX_VECTOR_WIDETAG:
2184 case COMPLEX_ARRAY_WIDETAG:
2185 case VALUE_CELL_HEADER_WIDETAG:
2186 case SYMBOL_HEADER_WIDETAG:
2188 case CODE_HEADER_WIDETAG:
2189 case BIGNUM_WIDETAG:
2190 case SINGLE_FLOAT_WIDETAG:
2191 case DOUBLE_FLOAT_WIDETAG:
2192 #ifdef LONG_FLOAT_WIDETAG
2193 case LONG_FLOAT_WIDETAG:
2195 case SIMPLE_BASE_STRING_WIDETAG:
2196 case SIMPLE_BIT_VECTOR_WIDETAG:
2197 case SIMPLE_ARRAY_NIL_WIDETAG:
2198 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2199 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2200 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2201 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2202 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2203 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2204 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2205 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2206 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2207 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2208 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2210 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2211 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2213 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2214 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2216 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2217 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2219 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2220 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2221 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2222 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2224 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2225 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2227 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2228 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2230 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2231 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2234 case WEAK_POINTER_WIDETAG:
2241 pointer, start_addr, *start_addr));
2249 pointer, start_addr, *start_addr));
2257 /* Adjust large bignum and vector objects. This will adjust the
2258 * allocated region if the size has shrunk, and move unboxed objects
2259 * into unboxed pages. The pages are not promoted here, and the
2260 * promoted region is not added to the new_regions; this is really
2261 * only designed to be called from preserve_pointer(). Shouldn't fail
2262 * if this is missed, just may delay the moving of objects to unboxed
2263 * pages, and the freeing of pages. */
2265 maybe_adjust_large_object(lispobj *where)
2270 int remaining_bytes;
2277 /* Check whether it's a vector or bignum object. */
2278 switch (widetag_of(where[0])) {
2279 case SIMPLE_VECTOR_WIDETAG:
2282 case BIGNUM_WIDETAG:
2283 case SIMPLE_BASE_STRING_WIDETAG:
2284 case SIMPLE_BIT_VECTOR_WIDETAG:
2285 case SIMPLE_ARRAY_NIL_WIDETAG:
2286 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2287 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2288 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2289 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2290 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2291 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2292 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2293 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2294 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2295 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2296 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2298 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2299 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2301 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2302 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2304 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2305 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2307 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2308 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2309 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2310 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2312 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2313 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2315 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2316 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2318 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2319 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2321 boxed = UNBOXED_PAGE;
2327 /* Find its current size. */
2328 nwords = (sizetab[widetag_of(where[0])])(where);
2330 first_page = find_page_index((void *)where);
2331 gc_assert(first_page >= 0);
2333 /* Note: Any page write-protection must be removed, else a later
2334 * scavenge_newspace may incorrectly not scavenge these pages.
2335 * This would not be necessary if they are added to the new areas,
2336 * but lets do it for them all (they'll probably be written
2339 gc_assert(page_table[first_page].first_object_offset == 0);
2341 next_page = first_page;
2342 remaining_bytes = nwords*4;
2343 while (remaining_bytes > PAGE_BYTES) {
2344 gc_assert(page_table[next_page].gen == from_space);
2345 gc_assert((page_table[next_page].allocated == BOXED_PAGE)
2346 || (page_table[next_page].allocated == UNBOXED_PAGE));
2347 gc_assert(page_table[next_page].large_object);
2348 gc_assert(page_table[next_page].first_object_offset ==
2349 -PAGE_BYTES*(next_page-first_page));
2350 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2352 page_table[next_page].allocated = boxed;
2354 /* Shouldn't be write-protected at this stage. Essential that the
2356 gc_assert(!page_table[next_page].write_protected);
2357 remaining_bytes -= PAGE_BYTES;
2361 /* Now only one page remains, but the object may have shrunk so
2362 * there may be more unused pages which will be freed. */
2364 /* Object may have shrunk but shouldn't have grown - check. */
2365 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2367 page_table[next_page].allocated = boxed;
2368 gc_assert(page_table[next_page].allocated ==
2369 page_table[first_page].allocated);
2371 /* Adjust the bytes_used. */
2372 old_bytes_used = page_table[next_page].bytes_used;
2373 page_table[next_page].bytes_used = remaining_bytes;
2375 bytes_freed = old_bytes_used - remaining_bytes;
2377 /* Free any remaining pages; needs care. */
2379 while ((old_bytes_used == PAGE_BYTES) &&
2380 (page_table[next_page].gen == from_space) &&
2381 ((page_table[next_page].allocated == UNBOXED_PAGE)
2382 || (page_table[next_page].allocated == BOXED_PAGE)) &&
2383 page_table[next_page].large_object &&
2384 (page_table[next_page].first_object_offset ==
2385 -(next_page - first_page)*PAGE_BYTES)) {
2386 /* It checks out OK, free the page. We don't need to both zeroing
2387 * pages as this should have been done before shrinking the
2388 * object. These pages shouldn't be write protected as they
2389 * should be zero filled. */
2390 gc_assert(page_table[next_page].write_protected == 0);
2392 old_bytes_used = page_table[next_page].bytes_used;
2393 page_table[next_page].allocated = FREE_PAGE;
2394 page_table[next_page].bytes_used = 0;
2395 bytes_freed += old_bytes_used;
2399 if ((bytes_freed > 0) && gencgc_verbose) {
2401 "/maybe_adjust_large_object() freed %d\n",
2405 generations[from_space].bytes_allocated -= bytes_freed;
2406 bytes_allocated -= bytes_freed;
2411 /* Take a possible pointer to a Lisp object and mark its page in the
2412 * page_table so that it will not be relocated during a GC.
2414 * This involves locating the page it points to, then backing up to
2415 * the start of its region, then marking all pages dont_move from there
2416 * up to the first page that's not full or has a different generation
2418 * It is assumed that all the page static flags have been cleared at
2419 * the start of a GC.
2421 * It is also assumed that the current gc_alloc() region has been
2422 * flushed and the tables updated. */
2424 preserve_pointer(void *addr)
2426 int addr_page_index = find_page_index(addr);
2429 unsigned region_allocation;
2431 /* quick check 1: Address is quite likely to have been invalid. */
2432 if ((addr_page_index == -1)
2433 || (page_table[addr_page_index].allocated == FREE_PAGE)
2434 || (page_table[addr_page_index].bytes_used == 0)
2435 || (page_table[addr_page_index].gen != from_space)
2436 /* Skip if already marked dont_move. */
2437 || (page_table[addr_page_index].dont_move != 0))
2439 gc_assert(!(page_table[addr_page_index].allocated & OPEN_REGION_PAGE));
2440 /* (Now that we know that addr_page_index is in range, it's
2441 * safe to index into page_table[] with it.) */
2442 region_allocation = page_table[addr_page_index].allocated;
2444 /* quick check 2: Check the offset within the page.
2447 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2450 /* Filter out anything which can't be a pointer to a Lisp object
2451 * (or, as a special case which also requires dont_move, a return
2452 * address referring to something in a CodeObject). This is
2453 * expensive but important, since it vastly reduces the
2454 * probability that random garbage will be bogusly interpreted as
2455 * a pointer which prevents a page from moving. */
2456 if (!(possibly_valid_dynamic_space_pointer(addr)))
2459 /* Find the beginning of the region. Note that there may be
2460 * objects in the region preceding the one that we were passed a
2461 * pointer to: if this is the case, we will write-protect all the
2462 * previous objects' pages too. */
2465 /* I think this'd work just as well, but without the assertions.
2466 * -dan 2004.01.01 */
2468 find_page_index(page_address(addr_page_index)+
2469 page_table[addr_page_index].first_object_offset);
2471 first_page = addr_page_index;
2472 while (page_table[first_page].first_object_offset != 0) {
2474 /* Do some checks. */
2475 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2476 gc_assert(page_table[first_page].gen == from_space);
2477 gc_assert(page_table[first_page].allocated == region_allocation);
2481 /* Adjust any large objects before promotion as they won't be
2482 * copied after promotion. */
2483 if (page_table[first_page].large_object) {
2484 maybe_adjust_large_object(page_address(first_page));
2485 /* If a large object has shrunk then addr may now point to a
2486 * free area in which case it's ignored here. Note it gets
2487 * through the valid pointer test above because the tail looks
2489 if ((page_table[addr_page_index].allocated == FREE_PAGE)
2490 || (page_table[addr_page_index].bytes_used == 0)
2491 /* Check the offset within the page. */
2492 || (((unsigned)addr & (PAGE_BYTES - 1))
2493 > page_table[addr_page_index].bytes_used)) {
2495 "weird? ignore ptr 0x%x to freed area of large object\n",
2499 /* It may have moved to unboxed pages. */
2500 region_allocation = page_table[first_page].allocated;
2503 /* Now work forward until the end of this contiguous area is found,
2504 * marking all pages as dont_move. */
2505 for (i = first_page; ;i++) {
2506 gc_assert(page_table[i].allocated == region_allocation);
2508 /* Mark the page static. */
2509 page_table[i].dont_move = 1;
2511 /* Move the page to the new_space. XX I'd rather not do this
2512 * but the GC logic is not quite able to copy with the static
2513 * pages remaining in the from space. This also requires the
2514 * generation bytes_allocated counters be updated. */
2515 page_table[i].gen = new_space;
2516 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2517 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2519 /* It is essential that the pages are not write protected as
2520 * they may have pointers into the old-space which need
2521 * scavenging. They shouldn't be write protected at this
2523 gc_assert(!page_table[i].write_protected);
2525 /* Check whether this is the last page in this contiguous block.. */
2526 if ((page_table[i].bytes_used < PAGE_BYTES)
2527 /* ..or it is PAGE_BYTES and is the last in the block */
2528 || (page_table[i+1].allocated == FREE_PAGE)
2529 || (page_table[i+1].bytes_used == 0) /* next page free */
2530 || (page_table[i+1].gen != from_space) /* diff. gen */
2531 || (page_table[i+1].first_object_offset == 0))
2535 /* Check that the page is now static. */
2536 gc_assert(page_table[addr_page_index].dont_move != 0);
2539 /* If the given page is not write-protected, then scan it for pointers
2540 * to younger generations or the top temp. generation, if no
2541 * suspicious pointers are found then the page is write-protected.
2543 * Care is taken to check for pointers to the current gc_alloc()
2544 * region if it is a younger generation or the temp. generation. This
2545 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2546 * the gc_alloc_generation does not need to be checked as this is only
2547 * called from scavenge_generation() when the gc_alloc generation is
2548 * younger, so it just checks if there is a pointer to the current
2551 * We return 1 if the page was write-protected, else 0. */
2553 update_page_write_prot(int page)
2555 int gen = page_table[page].gen;
2558 void **page_addr = (void **)page_address(page);
2559 int num_words = page_table[page].bytes_used / 4;
2561 /* Shouldn't be a free page. */
2562 gc_assert(page_table[page].allocated != FREE_PAGE);
2563 gc_assert(page_table[page].bytes_used != 0);
2565 /* Skip if it's already write-protected, pinned, or unboxed */
2566 if (page_table[page].write_protected
2567 || page_table[page].dont_move
2568 || (page_table[page].allocated & UNBOXED_PAGE))
2571 /* Scan the page for pointers to younger generations or the
2572 * top temp. generation. */
2574 for (j = 0; j < num_words; j++) {
2575 void *ptr = *(page_addr+j);
2576 int index = find_page_index(ptr);
2578 /* Check that it's in the dynamic space */
2580 if (/* Does it point to a younger or the temp. generation? */
2581 ((page_table[index].allocated != FREE_PAGE)
2582 && (page_table[index].bytes_used != 0)
2583 && ((page_table[index].gen < gen)
2584 || (page_table[index].gen == NUM_GENERATIONS)))
2586 /* Or does it point within a current gc_alloc() region? */
2587 || ((boxed_region.start_addr <= ptr)
2588 && (ptr <= boxed_region.free_pointer))
2589 || ((unboxed_region.start_addr <= ptr)
2590 && (ptr <= unboxed_region.free_pointer))) {
2597 /* Write-protect the page. */
2598 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2600 os_protect((void *)page_addr,
2602 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2604 /* Note the page as protected in the page tables. */
2605 page_table[page].write_protected = 1;
2611 /* Scavenge a generation.
2613 * This will not resolve all pointers when generation is the new
2614 * space, as new objects may be added which are not checked here - use
2615 * scavenge_newspace generation.
2617 * Write-protected pages should not have any pointers to the
2618 * from_space so do need scavenging; thus write-protected pages are
2619 * not always scavenged. There is some code to check that these pages
2620 * are not written; but to check fully the write-protected pages need
2621 * to be scavenged by disabling the code to skip them.
2623 * Under the current scheme when a generation is GCed the younger
2624 * generations will be empty. So, when a generation is being GCed it
2625 * is only necessary to scavenge the older generations for pointers
2626 * not the younger. So a page that does not have pointers to younger
2627 * generations does not need to be scavenged.
2629 * The write-protection can be used to note pages that don't have
2630 * pointers to younger pages. But pages can be written without having
2631 * pointers to younger generations. After the pages are scavenged here
2632 * they can be scanned for pointers to younger generations and if
2633 * there are none the page can be write-protected.
2635 * One complication is when the newspace is the top temp. generation.
2637 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2638 * that none were written, which they shouldn't be as they should have
2639 * no pointers to younger generations. This breaks down for weak
2640 * pointers as the objects contain a link to the next and are written
2641 * if a weak pointer is scavenged. Still it's a useful check. */
2643 scavenge_generation(int generation)
2650 /* Clear the write_protected_cleared flags on all pages. */
2651 for (i = 0; i < NUM_PAGES; i++)
2652 page_table[i].write_protected_cleared = 0;
2655 for (i = 0; i < last_free_page; i++) {
2656 if ((page_table[i].allocated & BOXED_PAGE)
2657 && (page_table[i].bytes_used != 0)
2658 && (page_table[i].gen == generation)) {
2660 int write_protected=1;
2662 /* This should be the start of a region */
2663 gc_assert(page_table[i].first_object_offset == 0);
2665 /* Now work forward until the end of the region */
2666 for (last_page = i; ; last_page++) {
2668 write_protected && page_table[last_page].write_protected;
2669 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2670 /* Or it is PAGE_BYTES and is the last in the block */
2671 || (!(page_table[last_page+1].allocated & BOXED_PAGE))
2672 || (page_table[last_page+1].bytes_used == 0)
2673 || (page_table[last_page+1].gen != generation)
2674 || (page_table[last_page+1].first_object_offset == 0))
2677 if (!write_protected) {
2678 scavenge(page_address(i), (page_table[last_page].bytes_used
2679 + (last_page-i)*PAGE_BYTES)/4);
2681 /* Now scan the pages and write protect those that
2682 * don't have pointers to younger generations. */
2683 if (enable_page_protection) {
2684 for (j = i; j <= last_page; j++) {
2685 num_wp += update_page_write_prot(j);
2692 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2694 "/write protected %d pages within generation %d\n",
2695 num_wp, generation));
2699 /* Check that none of the write_protected pages in this generation
2700 * have been written to. */
2701 for (i = 0; i < NUM_PAGES; i++) {
2702 if ((page_table[i].allocation ! =FREE_PAGE)
2703 && (page_table[i].bytes_used != 0)
2704 && (page_table[i].gen == generation)
2705 && (page_table[i].write_protected_cleared != 0)) {
2706 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2708 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2709 page_table[i].bytes_used,
2710 page_table[i].first_object_offset,
2711 page_table[i].dont_move));
2712 lose("write to protected page %d in scavenge_generation()", i);
2719 /* Scavenge a newspace generation. As it is scavenged new objects may
2720 * be allocated to it; these will also need to be scavenged. This
2721 * repeats until there are no more objects unscavenged in the
2722 * newspace generation.
2724 * To help improve the efficiency, areas written are recorded by
2725 * gc_alloc() and only these scavenged. Sometimes a little more will be
2726 * scavenged, but this causes no harm. An easy check is done that the
2727 * scavenged bytes equals the number allocated in the previous
2730 * Write-protected pages are not scanned except if they are marked
2731 * dont_move in which case they may have been promoted and still have
2732 * pointers to the from space.
2734 * Write-protected pages could potentially be written by alloc however
2735 * to avoid having to handle re-scavenging of write-protected pages
2736 * gc_alloc() does not write to write-protected pages.
2738 * New areas of objects allocated are recorded alternatively in the two
2739 * new_areas arrays below. */
2740 static struct new_area new_areas_1[NUM_NEW_AREAS];
2741 static struct new_area new_areas_2[NUM_NEW_AREAS];
2743 /* Do one full scan of the new space generation. This is not enough to
2744 * complete the job as new objects may be added to the generation in
2745 * the process which are not scavenged. */
2747 scavenge_newspace_generation_one_scan(int generation)
2752 "/starting one full scan of newspace generation %d\n",
2754 for (i = 0; i < last_free_page; i++) {
2755 /* note that this skips over open regions when it encounters them */
2756 if ((page_table[i].allocated & BOXED_PAGE)
2757 && (page_table[i].bytes_used != 0)
2758 && (page_table[i].gen == generation)
2759 && ((page_table[i].write_protected == 0)
2760 /* (This may be redundant as write_protected is now
2761 * cleared before promotion.) */
2762 || (page_table[i].dont_move == 1))) {
2766 /* The scavenge will start at the first_object_offset of page i.
2768 * We need to find the full extent of this contiguous
2769 * block in case objects span pages.
2771 * Now work forward until the end of this contiguous area
2772 * is found. A small area is preferred as there is a
2773 * better chance of its pages being write-protected. */
2774 for (last_page = i; ;last_page++) {
2775 /* If all pages are write-protected and movable,
2776 * then no need to scavenge */
2777 all_wp=all_wp && page_table[last_page].write_protected &&
2778 !page_table[last_page].dont_move;
2780 /* Check whether this is the last page in this
2781 * contiguous block */
2782 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2783 /* Or it is PAGE_BYTES and is the last in the block */
2784 || (!(page_table[last_page+1].allocated & BOXED_PAGE))
2785 || (page_table[last_page+1].bytes_used == 0)
2786 || (page_table[last_page+1].gen != generation)
2787 || (page_table[last_page+1].first_object_offset == 0))
2791 /* Do a limited check for write-protected pages. */
2795 size = (page_table[last_page].bytes_used
2796 + (last_page-i)*PAGE_BYTES
2797 - page_table[i].first_object_offset)/4;
2798 new_areas_ignore_page = last_page;
2800 scavenge(page_address(i) +
2801 page_table[i].first_object_offset,
2809 "/done with one full scan of newspace generation %d\n",
2813 /* Do a complete scavenge of the newspace generation. */
2815 scavenge_newspace_generation(int generation)
2819 /* the new_areas array currently being written to by gc_alloc() */
2820 struct new_area (*current_new_areas)[] = &new_areas_1;
2821 int current_new_areas_index;
2823 /* the new_areas created by the previous scavenge cycle */
2824 struct new_area (*previous_new_areas)[] = NULL;
2825 int previous_new_areas_index;
2827 /* Flush the current regions updating the tables. */
2828 gc_alloc_update_all_page_tables();
2830 /* Turn on the recording of new areas by gc_alloc(). */
2831 new_areas = current_new_areas;
2832 new_areas_index = 0;
2834 /* Don't need to record new areas that get scavenged anyway during
2835 * scavenge_newspace_generation_one_scan. */
2836 record_new_objects = 1;
2838 /* Start with a full scavenge. */
2839 scavenge_newspace_generation_one_scan(generation);
2841 /* Record all new areas now. */
2842 record_new_objects = 2;
2844 /* Flush the current regions updating the tables. */
2845 gc_alloc_update_all_page_tables();
2847 /* Grab new_areas_index. */
2848 current_new_areas_index = new_areas_index;
2851 "The first scan is finished; current_new_areas_index=%d.\n",
2852 current_new_areas_index));*/
2854 while (current_new_areas_index > 0) {
2855 /* Move the current to the previous new areas */
2856 previous_new_areas = current_new_areas;
2857 previous_new_areas_index = current_new_areas_index;
2859 /* Scavenge all the areas in previous new areas. Any new areas
2860 * allocated are saved in current_new_areas. */
2862 /* Allocate an array for current_new_areas; alternating between
2863 * new_areas_1 and 2 */
2864 if (previous_new_areas == &new_areas_1)
2865 current_new_areas = &new_areas_2;
2867 current_new_areas = &new_areas_1;
2869 /* Set up for gc_alloc(). */
2870 new_areas = current_new_areas;
2871 new_areas_index = 0;
2873 /* Check whether previous_new_areas had overflowed. */
2874 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2876 /* New areas of objects allocated have been lost so need to do a
2877 * full scan to be sure! If this becomes a problem try
2878 * increasing NUM_NEW_AREAS. */
2880 SHOW("new_areas overflow, doing full scavenge");
2882 /* Don't need to record new areas that get scavenge anyway
2883 * during scavenge_newspace_generation_one_scan. */
2884 record_new_objects = 1;
2886 scavenge_newspace_generation_one_scan(generation);
2888 /* Record all new areas now. */
2889 record_new_objects = 2;
2891 /* Flush the current regions updating the tables. */
2892 gc_alloc_update_all_page_tables();
2896 /* Work through previous_new_areas. */
2897 for (i = 0; i < previous_new_areas_index; i++) {
2898 /* FIXME: All these bare *4 and /4 should be something
2899 * like BYTES_PER_WORD or WBYTES. */
2900 int page = (*previous_new_areas)[i].page;
2901 int offset = (*previous_new_areas)[i].offset;
2902 int size = (*previous_new_areas)[i].size / 4;
2903 gc_assert((*previous_new_areas)[i].size % 4 == 0);
2904 scavenge(page_address(page)+offset, size);
2907 /* Flush the current regions updating the tables. */
2908 gc_alloc_update_all_page_tables();
2911 current_new_areas_index = new_areas_index;
2914 "The re-scan has finished; current_new_areas_index=%d.\n",
2915 current_new_areas_index));*/
2918 /* Turn off recording of areas allocated by gc_alloc(). */
2919 record_new_objects = 0;
2922 /* Check that none of the write_protected pages in this generation
2923 * have been written to. */
2924 for (i = 0; i < NUM_PAGES; i++) {
2925 if ((page_table[i].allocation != FREE_PAGE)
2926 && (page_table[i].bytes_used != 0)
2927 && (page_table[i].gen == generation)
2928 && (page_table[i].write_protected_cleared != 0)
2929 && (page_table[i].dont_move == 0)) {
2930 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2931 i, generation, page_table[i].dont_move);
2937 /* Un-write-protect all the pages in from_space. This is done at the
2938 * start of a GC else there may be many page faults while scavenging
2939 * the newspace (I've seen drive the system time to 99%). These pages
2940 * would need to be unprotected anyway before unmapping in
2941 * free_oldspace; not sure what effect this has on paging.. */
2943 unprotect_oldspace(void)
2947 for (i = 0; i < last_free_page; i++) {
2948 if ((page_table[i].allocated != FREE_PAGE)
2949 && (page_table[i].bytes_used != 0)
2950 && (page_table[i].gen == from_space)) {
2953 page_start = (void *)page_address(i);
2955 /* Remove any write-protection. We should be able to rely
2956 * on the write-protect flag to avoid redundant calls. */
2957 if (page_table[i].write_protected) {
2958 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2959 page_table[i].write_protected = 0;
2965 /* Work through all the pages and free any in from_space. This
2966 * assumes that all objects have been copied or promoted to an older
2967 * generation. Bytes_allocated and the generation bytes_allocated
2968 * counter are updated. The number of bytes freed is returned. */
2969 extern void i586_bzero(void *addr, int nbytes);
2973 int bytes_freed = 0;
2974 int first_page, last_page;
2979 /* Find a first page for the next region of pages. */
2980 while ((first_page < last_free_page)
2981 && ((page_table[first_page].allocated == FREE_PAGE)
2982 || (page_table[first_page].bytes_used == 0)
2983 || (page_table[first_page].gen != from_space)))
2986 if (first_page >= last_free_page)
2989 /* Find the last page of this region. */
2990 last_page = first_page;
2993 /* Free the page. */
2994 bytes_freed += page_table[last_page].bytes_used;
2995 generations[page_table[last_page].gen].bytes_allocated -=
2996 page_table[last_page].bytes_used;
2997 page_table[last_page].allocated = FREE_PAGE;
2998 page_table[last_page].bytes_used = 0;
3000 /* Remove any write-protection. We should be able to rely
3001 * on the write-protect flag to avoid redundant calls. */
3003 void *page_start = (void *)page_address(last_page);
3005 if (page_table[last_page].write_protected) {
3006 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3007 page_table[last_page].write_protected = 0;
3012 while ((last_page < last_free_page)
3013 && (page_table[last_page].allocated != FREE_PAGE)
3014 && (page_table[last_page].bytes_used != 0)
3015 && (page_table[last_page].gen == from_space));
3017 /* Zero pages from first_page to (last_page-1).
3019 * FIXME: Why not use os_zero(..) function instead of
3020 * hand-coding this again? (Check other gencgc_unmap_zero
3022 if (gencgc_unmap_zero) {
3023 void *page_start, *addr;
3025 page_start = (void *)page_address(first_page);
3027 os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
3028 addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
3029 if (addr == NULL || addr != page_start) {
3030 /* Is this an error condition? I couldn't really tell from
3031 * the old CMU CL code, which fprintf'ed a message with
3032 * an exclamation point at the end. But I've never seen the
3033 * message, so it must at least be unusual..
3035 * (The same condition is also tested for in gc_free_heap.)
3037 * -- WHN 19991129 */
3038 lose("i586_bzero: page moved, 0x%08x ==> 0x%08x",
3045 page_start = (int *)page_address(first_page);
3046 i586_bzero(page_start, PAGE_BYTES*(last_page-first_page));
3049 first_page = last_page;
3051 } while (first_page < last_free_page);
3053 bytes_allocated -= bytes_freed;
3058 /* Print some information about a pointer at the given address. */
3060 print_ptr(lispobj *addr)
3062 /* If addr is in the dynamic space then out the page information. */
3063 int pi1 = find_page_index((void*)addr);
3066 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3067 (unsigned int) addr,
3069 page_table[pi1].allocated,
3070 page_table[pi1].gen,
3071 page_table[pi1].bytes_used,
3072 page_table[pi1].first_object_offset,
3073 page_table[pi1].dont_move);
3074 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3087 extern int undefined_tramp;
3090 verify_space(lispobj *start, size_t words)
3092 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3093 int is_in_readonly_space =
3094 (READ_ONLY_SPACE_START <= (unsigned)start &&
3095 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3099 lispobj thing = *(lispobj*)start;
3101 if (is_lisp_pointer(thing)) {
3102 int page_index = find_page_index((void*)thing);
3103 int to_readonly_space =
3104 (READ_ONLY_SPACE_START <= thing &&
3105 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3106 int to_static_space =
3107 (STATIC_SPACE_START <= thing &&
3108 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3110 /* Does it point to the dynamic space? */
3111 if (page_index != -1) {
3112 /* If it's within the dynamic space it should point to a used
3113 * page. XX Could check the offset too. */
3114 if ((page_table[page_index].allocated != FREE_PAGE)
3115 && (page_table[page_index].bytes_used == 0))
3116 lose ("Ptr %x @ %x sees free page.", thing, start);
3117 /* Check that it doesn't point to a forwarding pointer! */
3118 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3119 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3121 /* Check that its not in the RO space as it would then be a
3122 * pointer from the RO to the dynamic space. */
3123 if (is_in_readonly_space) {
3124 lose("ptr to dynamic space %x from RO space %x",
3127 /* Does it point to a plausible object? This check slows
3128 * it down a lot (so it's commented out).
3130 * "a lot" is serious: it ate 50 minutes cpu time on
3131 * my duron 950 before I came back from lunch and
3134 * FIXME: Add a variable to enable this
3137 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3138 lose("ptr %x to invalid object %x", thing, start);
3142 /* Verify that it points to another valid space. */
3143 if (!to_readonly_space && !to_static_space
3144 && (thing != (unsigned)&undefined_tramp)) {
3145 lose("Ptr %x @ %x sees junk.", thing, start);
3149 if (!(fixnump(thing))) {
3151 switch(widetag_of(*start)) {
3154 case SIMPLE_VECTOR_WIDETAG:
3156 case COMPLEX_WIDETAG:
3157 case SIMPLE_ARRAY_WIDETAG:
3158 case COMPLEX_BASE_STRING_WIDETAG:
3159 case COMPLEX_VECTOR_NIL_WIDETAG:
3160 case COMPLEX_BIT_VECTOR_WIDETAG:
3161 case COMPLEX_VECTOR_WIDETAG:
3162 case COMPLEX_ARRAY_WIDETAG:
3163 case CLOSURE_HEADER_WIDETAG:
3164 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3165 case VALUE_CELL_HEADER_WIDETAG:
3166 case SYMBOL_HEADER_WIDETAG:
3167 case BASE_CHAR_WIDETAG:
3168 case UNBOUND_MARKER_WIDETAG:
3169 case INSTANCE_HEADER_WIDETAG:
3174 case CODE_HEADER_WIDETAG:
3176 lispobj object = *start;
3178 int nheader_words, ncode_words, nwords;
3180 struct simple_fun *fheaderp;
3182 code = (struct code *) start;
3184 /* Check that it's not in the dynamic space.
3185 * FIXME: Isn't is supposed to be OK for code
3186 * objects to be in the dynamic space these days? */
3187 if (is_in_dynamic_space
3188 /* It's ok if it's byte compiled code. The trace
3189 * table offset will be a fixnum if it's x86
3190 * compiled code - check.
3192 * FIXME: #^#@@! lack of abstraction here..
3193 * This line can probably go away now that
3194 * there's no byte compiler, but I've got
3195 * too much to worry about right now to try
3196 * to make sure. -- WHN 2001-10-06 */
3197 && fixnump(code->trace_table_offset)
3198 /* Only when enabled */
3199 && verify_dynamic_code_check) {
3201 "/code object at %x in the dynamic space\n",
3205 ncode_words = fixnum_value(code->code_size);
3206 nheader_words = HeaderValue(object);
3207 nwords = ncode_words + nheader_words;
3208 nwords = CEILING(nwords, 2);
3209 /* Scavenge the boxed section of the code data block */
3210 verify_space(start + 1, nheader_words - 1);
3212 /* Scavenge the boxed section of each function
3213 * object in the code data block. */
3214 fheaderl = code->entry_points;
3215 while (fheaderl != NIL) {
3217 (struct simple_fun *) native_pointer(fheaderl);
3218 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3219 verify_space(&fheaderp->name, 1);
3220 verify_space(&fheaderp->arglist, 1);
3221 verify_space(&fheaderp->type, 1);
3222 fheaderl = fheaderp->next;
3228 /* unboxed objects */
3229 case BIGNUM_WIDETAG:
3230 case SINGLE_FLOAT_WIDETAG:
3231 case DOUBLE_FLOAT_WIDETAG:
3232 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3233 case LONG_FLOAT_WIDETAG:
3235 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3236 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3238 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3239 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3241 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3242 case COMPLEX_LONG_FLOAT_WIDETAG:
3244 case SIMPLE_BASE_STRING_WIDETAG:
3245 case SIMPLE_BIT_VECTOR_WIDETAG:
3246 case SIMPLE_ARRAY_NIL_WIDETAG:
3247 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3248 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3249 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3250 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3251 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3252 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3253 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3254 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3255 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3256 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3257 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3259 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3260 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3262 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3263 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3265 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3266 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3268 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3269 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3270 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3271 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3273 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3274 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3276 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3277 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3279 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3280 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3283 case WEAK_POINTER_WIDETAG:
3284 count = (sizetab[widetag_of(*start)])(start);
3300 /* FIXME: It would be nice to make names consistent so that
3301 * foo_size meant size *in* *bytes* instead of size in some
3302 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3303 * Some counts of lispobjs are called foo_count; it might be good
3304 * to grep for all foo_size and rename the appropriate ones to
3306 int read_only_space_size =
3307 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3308 - (lispobj*)READ_ONLY_SPACE_START;
3309 int static_space_size =
3310 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3311 - (lispobj*)STATIC_SPACE_START;
3313 for_each_thread(th) {
3314 int binding_stack_size =
3315 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3316 - (lispobj*)th->binding_stack_start;
3317 verify_space(th->binding_stack_start, binding_stack_size);
3319 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3320 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3324 verify_generation(int generation)
3328 for (i = 0; i < last_free_page; i++) {
3329 if ((page_table[i].allocated != FREE_PAGE)
3330 && (page_table[i].bytes_used != 0)
3331 && (page_table[i].gen == generation)) {
3333 int region_allocation = page_table[i].allocated;
3335 /* This should be the start of a contiguous block */
3336 gc_assert(page_table[i].first_object_offset == 0);
3338 /* Need to find the full extent of this contiguous block in case
3339 objects span pages. */
3341 /* Now work forward until the end of this contiguous area is
3343 for (last_page = i; ;last_page++)
3344 /* Check whether this is the last page in this contiguous
3346 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3347 /* Or it is PAGE_BYTES and is the last in the block */
3348 || (page_table[last_page+1].allocated != region_allocation)
3349 || (page_table[last_page+1].bytes_used == 0)
3350 || (page_table[last_page+1].gen != generation)
3351 || (page_table[last_page+1].first_object_offset == 0))
3354 verify_space(page_address(i), (page_table[last_page].bytes_used
3355 + (last_page-i)*PAGE_BYTES)/4);
3361 /* Check that all the free space is zero filled. */
3363 verify_zero_fill(void)
3367 for (page = 0; page < last_free_page; page++) {
3368 if (page_table[page].allocated == FREE_PAGE) {
3369 /* The whole page should be zero filled. */
3370 int *start_addr = (int *)page_address(page);
3373 for (i = 0; i < size; i++) {
3374 if (start_addr[i] != 0) {
3375 lose("free page not zero at %x", start_addr + i);
3379 int free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3380 if (free_bytes > 0) {
3381 int *start_addr = (int *)((unsigned)page_address(page)
3382 + page_table[page].bytes_used);
3383 int size = free_bytes / 4;
3385 for (i = 0; i < size; i++) {
3386 if (start_addr[i] != 0) {
3387 lose("free region not zero at %x", start_addr + i);
3395 /* External entry point for verify_zero_fill */
3397 gencgc_verify_zero_fill(void)
3399 /* Flush the alloc regions updating the tables. */
3400 gc_alloc_update_all_page_tables();
3401 SHOW("verifying zero fill");
3406 verify_dynamic_space(void)
3410 for (i = 0; i < NUM_GENERATIONS; i++)
3411 verify_generation(i);
3413 if (gencgc_enable_verify_zero_fill)
3417 /* Write-protect all the dynamic boxed pages in the given generation. */
3419 write_protect_generation_pages(int generation)
3423 gc_assert(generation < NUM_GENERATIONS);
3425 for (i = 0; i < last_free_page; i++)
3426 if ((page_table[i].allocated == BOXED_PAGE)
3427 && (page_table[i].bytes_used != 0)
3428 && !page_table[i].dont_move
3429 && (page_table[i].gen == generation)) {
3432 page_start = (void *)page_address(i);
3434 os_protect(page_start,
3436 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3438 /* Note the page as protected in the page tables. */
3439 page_table[i].write_protected = 1;
3442 if (gencgc_verbose > 1) {
3444 "/write protected %d of %d pages in generation %d\n",
3445 count_write_protect_generation_pages(generation),
3446 count_generation_pages(generation),
3451 /* Garbage collect a generation. If raise is 0 then the remains of the
3452 * generation are not raised to the next generation. */
3454 garbage_collect_generation(int generation, int raise)
3456 unsigned long bytes_freed;
3458 unsigned long static_space_size;
3460 gc_assert(generation <= (NUM_GENERATIONS-1));
3462 /* The oldest generation can't be raised. */
3463 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3465 /* Initialize the weak pointer list. */
3466 weak_pointers = NULL;
3468 /* When a generation is not being raised it is transported to a
3469 * temporary generation (NUM_GENERATIONS), and lowered when
3470 * done. Set up this new generation. There should be no pages
3471 * allocated to it yet. */
3473 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3475 /* Set the global src and dest. generations */
3476 from_space = generation;
3478 new_space = generation+1;
3480 new_space = NUM_GENERATIONS;
3482 /* Change to a new space for allocation, resetting the alloc_start_page */
3483 gc_alloc_generation = new_space;
3484 generations[new_space].alloc_start_page = 0;
3485 generations[new_space].alloc_unboxed_start_page = 0;
3486 generations[new_space].alloc_large_start_page = 0;
3487 generations[new_space].alloc_large_unboxed_start_page = 0;
3489 /* Before any pointers are preserved, the dont_move flags on the
3490 * pages need to be cleared. */
3491 for (i = 0; i < last_free_page; i++)
3492 if(page_table[i].gen==from_space)
3493 page_table[i].dont_move = 0;
3495 /* Un-write-protect the old-space pages. This is essential for the
3496 * promoted pages as they may contain pointers into the old-space
3497 * which need to be scavenged. It also helps avoid unnecessary page
3498 * faults as forwarding pointers are written into them. They need to
3499 * be un-protected anyway before unmapping later. */
3500 unprotect_oldspace();
3502 /* Scavenge the stacks' conservative roots. */
3504 /* there are potentially two stacks for each thread: the main
3505 * stack, which may contain Lisp pointers, and the alternate stack.
3506 * We don't ever run Lisp code on the altstack, but it may
3507 * host a sigcontext with lisp objects in it */
3509 /* what we need to do: (1) find the stack pointer for the main
3510 * stack; scavenge it (2) find the interrupt context on the
3511 * alternate stack that might contain lisp values, and scavenge
3514 /* we assume that none of the preceding applies to the thread that
3515 * initiates GC. If you ever call GC from inside an altstack
3516 * handler, you will lose. */
3517 for_each_thread(th) {
3519 void **esp=(void **)-1;
3521 #ifdef LISP_FEATURE_SB_THREAD
3522 if(th==arch_os_get_current_thread()) {
3523 esp = (void **) &raise;
3526 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3527 for(i=free-1;i>=0;i--) {
3528 os_context_t *c=th->interrupt_contexts[i];
3529 esp1 = (void **) *os_context_register_addr(c,reg_ESP);
3530 if(esp1>=th->control_stack_start&& esp1<th->control_stack_end){
3531 if(esp1<esp) esp=esp1;
3532 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3533 preserve_pointer(*ptr);
3539 esp = (void **) &raise;
3541 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3542 preserve_pointer(*ptr);
3547 if (gencgc_verbose > 1) {
3548 int num_dont_move_pages = count_dont_move_pages();
3550 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3551 num_dont_move_pages,
3552 num_dont_move_pages * PAGE_BYTES);
3556 /* Scavenge all the rest of the roots. */
3558 /* Scavenge the Lisp functions of the interrupt handlers, taking
3559 * care to avoid SIG_DFL and SIG_IGN. */
3560 for_each_thread(th) {
3561 struct interrupt_data *data=th->interrupt_data;
3562 for (i = 0; i < NSIG; i++) {
3563 union interrupt_handler handler = data->interrupt_handlers[i];
3564 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3565 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3566 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3570 /* Scavenge the binding stacks. */
3573 for_each_thread(th) {
3574 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3575 th->binding_stack_start;
3576 scavenge((lispobj *) th->binding_stack_start,len);
3577 #ifdef LISP_FEATURE_SB_THREAD
3578 /* do the tls as well */
3579 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3580 (sizeof (struct thread))/(sizeof (lispobj));
3581 scavenge((lispobj *) (th+1),len);
3586 /* The original CMU CL code had scavenge-read-only-space code
3587 * controlled by the Lisp-level variable
3588 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3589 * wasn't documented under what circumstances it was useful or
3590 * safe to turn it on, so it's been turned off in SBCL. If you
3591 * want/need this functionality, and can test and document it,
3592 * please submit a patch. */
3594 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3595 unsigned long read_only_space_size =
3596 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3597 (lispobj*)READ_ONLY_SPACE_START;
3599 "/scavenge read only space: %d bytes\n",
3600 read_only_space_size * sizeof(lispobj)));
3601 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3605 /* Scavenge static space. */
3607 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3608 (lispobj *)STATIC_SPACE_START;
3609 if (gencgc_verbose > 1) {
3611 "/scavenge static space: %d bytes\n",
3612 static_space_size * sizeof(lispobj)));
3614 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3616 /* All generations but the generation being GCed need to be
3617 * scavenged. The new_space generation needs special handling as
3618 * objects may be moved in - it is handled separately below. */
3619 for (i = 0; i < NUM_GENERATIONS; i++) {
3620 if ((i != generation) && (i != new_space)) {
3621 scavenge_generation(i);
3625 /* Finally scavenge the new_space generation. Keep going until no
3626 * more objects are moved into the new generation */
3627 scavenge_newspace_generation(new_space);
3629 /* FIXME: I tried reenabling this check when debugging unrelated
3630 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3631 * Since the current GC code seems to work well, I'm guessing that
3632 * this debugging code is just stale, but I haven't tried to
3633 * figure it out. It should be figured out and then either made to
3634 * work or just deleted. */
3635 #define RESCAN_CHECK 0
3637 /* As a check re-scavenge the newspace once; no new objects should
3640 int old_bytes_allocated = bytes_allocated;
3641 int bytes_allocated;
3643 /* Start with a full scavenge. */
3644 scavenge_newspace_generation_one_scan(new_space);
3646 /* Flush the current regions, updating the tables. */
3647 gc_alloc_update_all_page_tables();
3649 bytes_allocated = bytes_allocated - old_bytes_allocated;
3651 if (bytes_allocated != 0) {
3652 lose("Rescan of new_space allocated %d more bytes.",
3658 scan_weak_pointers();
3660 /* Flush the current regions, updating the tables. */
3661 gc_alloc_update_all_page_tables();
3663 /* Free the pages in oldspace, but not those marked dont_move. */
3664 bytes_freed = free_oldspace();
3666 /* If the GC is not raising the age then lower the generation back
3667 * to its normal generation number */
3669 for (i = 0; i < last_free_page; i++)
3670 if ((page_table[i].bytes_used != 0)
3671 && (page_table[i].gen == NUM_GENERATIONS))
3672 page_table[i].gen = generation;
3673 gc_assert(generations[generation].bytes_allocated == 0);
3674 generations[generation].bytes_allocated =
3675 generations[NUM_GENERATIONS].bytes_allocated;
3676 generations[NUM_GENERATIONS].bytes_allocated = 0;
3679 /* Reset the alloc_start_page for generation. */
3680 generations[generation].alloc_start_page = 0;
3681 generations[generation].alloc_unboxed_start_page = 0;
3682 generations[generation].alloc_large_start_page = 0;
3683 generations[generation].alloc_large_unboxed_start_page = 0;
3685 if (generation >= verify_gens) {
3689 verify_dynamic_space();
3692 /* Set the new gc trigger for the GCed generation. */
3693 generations[generation].gc_trigger =
3694 generations[generation].bytes_allocated
3695 + generations[generation].bytes_consed_between_gc;
3698 generations[generation].num_gc = 0;
3700 ++generations[generation].num_gc;
3703 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3705 update_x86_dynamic_space_free_pointer(void)
3710 for (i = 0; i < NUM_PAGES; i++)
3711 if ((page_table[i].allocated != FREE_PAGE)
3712 && (page_table[i].bytes_used != 0))
3715 last_free_page = last_page+1;
3717 SetSymbolValue(ALLOCATION_POINTER,
3718 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3719 return 0; /* dummy value: return something ... */
3722 /* GC all generations newer than last_gen, raising the objects in each
3723 * to the next older generation - we finish when all generations below
3724 * last_gen are empty. Then if last_gen is due for a GC, or if
3725 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3726 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3728 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3729 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3732 collect_garbage(unsigned last_gen)
3739 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3741 if (last_gen > NUM_GENERATIONS) {
3743 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3748 /* Flush the alloc regions updating the tables. */
3749 gc_alloc_update_all_page_tables();
3751 /* Verify the new objects created by Lisp code. */
3752 if (pre_verify_gen_0) {
3753 FSHOW((stderr, "pre-checking generation 0\n"));
3754 verify_generation(0);
3757 if (gencgc_verbose > 1)
3758 print_generation_stats(0);
3761 /* Collect the generation. */
3763 if (gen >= gencgc_oldest_gen_to_gc) {
3764 /* Never raise the oldest generation. */
3769 || (generations[gen].num_gc >= generations[gen].trigger_age);
3772 if (gencgc_verbose > 1) {
3774 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3777 generations[gen].bytes_allocated,
3778 generations[gen].gc_trigger,
3779 generations[gen].num_gc));
3782 /* If an older generation is being filled, then update its
3785 generations[gen+1].cum_sum_bytes_allocated +=
3786 generations[gen+1].bytes_allocated;
3789 garbage_collect_generation(gen, raise);
3791 /* Reset the memory age cum_sum. */
3792 generations[gen].cum_sum_bytes_allocated = 0;
3794 if (gencgc_verbose > 1) {
3795 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3796 print_generation_stats(0);
3800 } while ((gen <= gencgc_oldest_gen_to_gc)
3801 && ((gen < last_gen)
3802 || ((gen <= gencgc_oldest_gen_to_gc)
3804 && (generations[gen].bytes_allocated
3805 > generations[gen].gc_trigger)
3806 && (gen_av_mem_age(gen)
3807 > generations[gen].min_av_mem_age))));
3809 /* Now if gen-1 was raised all generations before gen are empty.
3810 * If it wasn't raised then all generations before gen-1 are empty.
3812 * Now objects within this gen's pages cannot point to younger
3813 * generations unless they are written to. This can be exploited
3814 * by write-protecting the pages of gen; then when younger
3815 * generations are GCed only the pages which have been written
3820 gen_to_wp = gen - 1;
3822 /* There's not much point in WPing pages in generation 0 as it is
3823 * never scavenged (except promoted pages). */
3824 if ((gen_to_wp > 0) && enable_page_protection) {
3825 /* Check that they are all empty. */
3826 for (i = 0; i < gen_to_wp; i++) {
3827 if (generations[i].bytes_allocated)
3828 lose("trying to write-protect gen. %d when gen. %d nonempty",
3831 write_protect_generation_pages(gen_to_wp);
3834 /* Set gc_alloc() back to generation 0. The current regions should
3835 * be flushed after the above GCs. */
3836 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3837 gc_alloc_generation = 0;
3839 update_x86_dynamic_space_free_pointer();
3840 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3842 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3844 SHOW("returning from collect_garbage");
3847 /* This is called by Lisp PURIFY when it is finished. All live objects
3848 * will have been moved to the RO and Static heaps. The dynamic space
3849 * will need a full re-initialization. We don't bother having Lisp
3850 * PURIFY flush the current gc_alloc() region, as the page_tables are
3851 * re-initialized, and every page is zeroed to be sure. */
3857 if (gencgc_verbose > 1)
3858 SHOW("entering gc_free_heap");
3860 for (page = 0; page < NUM_PAGES; page++) {
3861 /* Skip free pages which should already be zero filled. */
3862 if (page_table[page].allocated != FREE_PAGE) {
3863 void *page_start, *addr;
3865 /* Mark the page free. The other slots are assumed invalid
3866 * when it is a FREE_PAGE and bytes_used is 0 and it
3867 * should not be write-protected -- except that the
3868 * generation is used for the current region but it sets
3870 page_table[page].allocated = FREE_PAGE;
3871 page_table[page].bytes_used = 0;
3873 /* Zero the page. */
3874 page_start = (void *)page_address(page);
3876 /* First, remove any write-protection. */
3877 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3878 page_table[page].write_protected = 0;
3880 os_invalidate(page_start,PAGE_BYTES);
3881 addr = os_validate(page_start,PAGE_BYTES);
3882 if (addr == NULL || addr != page_start) {
3883 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3887 } else if (gencgc_zero_check_during_free_heap) {
3888 /* Double-check that the page is zero filled. */
3890 gc_assert(page_table[page].allocated == FREE_PAGE);
3891 gc_assert(page_table[page].bytes_used == 0);
3892 page_start = (int *)page_address(page);
3893 for (i=0; i<1024; i++) {
3894 if (page_start[i] != 0) {
3895 lose("free region not zero at %x", page_start + i);
3901 bytes_allocated = 0;
3903 /* Initialize the generations. */
3904 for (page = 0; page < NUM_GENERATIONS; page++) {
3905 generations[page].alloc_start_page = 0;
3906 generations[page].alloc_unboxed_start_page = 0;
3907 generations[page].alloc_large_start_page = 0;
3908 generations[page].alloc_large_unboxed_start_page = 0;
3909 generations[page].bytes_allocated = 0;
3910 generations[page].gc_trigger = 2000000;
3911 generations[page].num_gc = 0;
3912 generations[page].cum_sum_bytes_allocated = 0;
3915 if (gencgc_verbose > 1)
3916 print_generation_stats(0);
3918 /* Initialize gc_alloc(). */
3919 gc_alloc_generation = 0;
3921 gc_set_region_empty(&boxed_region);
3922 gc_set_region_empty(&unboxed_region);
3925 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3927 if (verify_after_free_heap) {
3928 /* Check whether purify has left any bad pointers. */
3930 SHOW("checking after free_heap\n");
3941 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
3942 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
3943 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
3945 heap_base = (void*)DYNAMIC_SPACE_START;
3947 /* Initialize each page structure. */
3948 for (i = 0; i < NUM_PAGES; i++) {
3949 /* Initialize all pages as free. */
3950 page_table[i].allocated = FREE_PAGE;
3951 page_table[i].bytes_used = 0;
3953 /* Pages are not write-protected at startup. */
3954 page_table[i].write_protected = 0;
3957 bytes_allocated = 0;
3959 /* Initialize the generations.
3961 * FIXME: very similar to code in gc_free_heap(), should be shared */
3962 for (i = 0; i < NUM_GENERATIONS; i++) {
3963 generations[i].alloc_start_page = 0;
3964 generations[i].alloc_unboxed_start_page = 0;
3965 generations[i].alloc_large_start_page = 0;
3966 generations[i].alloc_large_unboxed_start_page = 0;
3967 generations[i].bytes_allocated = 0;
3968 generations[i].gc_trigger = 2000000;
3969 generations[i].num_gc = 0;
3970 generations[i].cum_sum_bytes_allocated = 0;
3971 /* the tune-able parameters */
3972 generations[i].bytes_consed_between_gc = 2000000;
3973 generations[i].trigger_age = 1;
3974 generations[i].min_av_mem_age = 0.75;
3977 /* Initialize gc_alloc. */
3978 gc_alloc_generation = 0;
3979 gc_set_region_empty(&boxed_region);
3980 gc_set_region_empty(&unboxed_region);
3986 /* Pick up the dynamic space from after a core load.
3988 * The ALLOCATION_POINTER points to the end of the dynamic space.
3992 gencgc_pickup_dynamic(void)
3995 int alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
3996 lispobj *prev=(lispobj *)page_address(page);
3999 lispobj *first,*ptr= (lispobj *)page_address(page);
4000 page_table[page].allocated = BOXED_PAGE;
4001 page_table[page].gen = 0;
4002 page_table[page].bytes_used = PAGE_BYTES;
4003 page_table[page].large_object = 0;
4005 first=search_space(prev,(ptr+2)-prev,ptr);
4006 if(ptr == first) prev=ptr;
4007 page_table[page].first_object_offset =
4008 (void *)prev - page_address(page);
4010 } while (page_address(page) < alloc_ptr);
4012 generations[0].bytes_allocated = PAGE_BYTES*page;
4013 bytes_allocated = PAGE_BYTES*page;
4019 gc_initialize_pointers(void)
4021 gencgc_pickup_dynamic();
4027 /* alloc(..) is the external interface for memory allocation. It
4028 * allocates to generation 0. It is not called from within the garbage
4029 * collector as it is only external uses that need the check for heap
4030 * size (GC trigger) and to disable the interrupts (interrupts are
4031 * always disabled during a GC).
4033 * The vops that call alloc(..) assume that the returned space is zero-filled.
4034 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4036 * The check for a GC trigger is only performed when the current
4037 * region is full, so in most cases it's not needed. */
4042 struct thread *th=arch_os_get_current_thread();
4043 struct alloc_region *region=
4044 th ? &(th->alloc_region) : &boxed_region;
4046 void *new_free_pointer;
4048 /* Check for alignment allocation problems. */
4049 gc_assert((((unsigned)region->free_pointer & 0x7) == 0)
4050 && ((nbytes & 0x7) == 0));
4052 /* there are a few places in the C code that allocate data in the
4053 * heap before Lisp starts. This is before interrupts are enabled,
4054 * so we don't need to check for pseudo-atomic */
4055 #ifdef LISP_FEATURE_SB_THREAD
4056 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4058 fprintf(stderr, "fatal error in thread 0x%x, pid=%d\n",
4060 __asm__("movl %fs,%0" : "=r" (fs) : );
4061 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4062 debug_get_fs(),th->tls_cookie);
4063 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4066 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4069 /* maybe we can do this quickly ... */
4070 new_free_pointer = region->free_pointer + nbytes;
4071 if (new_free_pointer <= region->end_addr) {
4072 new_obj = (void*)(region->free_pointer);
4073 region->free_pointer = new_free_pointer;
4074 return(new_obj); /* yup */
4077 /* we have to go the long way around, it seems. Check whether
4078 * we should GC in the near future
4080 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4081 /* set things up so that GC happens when we finish the PA
4082 * section. We only do this if there wasn't a pending handler
4083 * already, in case it was a gc. If it wasn't a GC, the next
4084 * allocation will get us back to this point anyway, so no harm done
4086 struct interrupt_data *data=th->interrupt_data;
4087 if(!data->pending_handler)
4088 maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0);
4090 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4095 /* Find the code object for the given pc, or return NULL on failure.
4097 * FIXME: PC shouldn't be lispobj*, should it? Maybe void*? */
4099 component_ptr_from_pc(lispobj *pc)
4101 lispobj *object = NULL;
4103 if ( (object = search_read_only_space(pc)) )
4105 else if ( (object = search_static_space(pc)) )
4108 object = search_dynamic_space(pc);
4110 if (object) /* if we found something */
4111 if (widetag_of(*object) == CODE_HEADER_WIDETAG) /* if it's a code object */
4118 * shared support for the OS-dependent signal handlers which
4119 * catch GENCGC-related write-protect violations
4122 void unhandled_sigmemoryfault(void);
4124 /* Depending on which OS we're running under, different signals might
4125 * be raised for a violation of write protection in the heap. This
4126 * function factors out the common generational GC magic which needs
4127 * to invoked in this case, and should be called from whatever signal
4128 * handler is appropriate for the OS we're running under.
4130 * Return true if this signal is a normal generational GC thing that
4131 * we were able to handle, or false if it was abnormal and control
4132 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4135 gencgc_handle_wp_violation(void* fault_addr)
4137 int page_index = find_page_index(fault_addr);
4139 #if defined QSHOW_SIGNALS
4140 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4141 fault_addr, page_index));
4144 /* Check whether the fault is within the dynamic space. */
4145 if (page_index == (-1)) {
4147 /* It can be helpful to be able to put a breakpoint on this
4148 * case to help diagnose low-level problems. */
4149 unhandled_sigmemoryfault();
4151 /* not within the dynamic space -- not our responsibility */
4155 if (page_table[page_index].write_protected) {
4156 /* Unprotect the page. */
4157 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4158 page_table[page_index].write_protected_cleared = 1;
4159 page_table[page_index].write_protected = 0;
4161 /* The only acceptable reason for this signal on a heap
4162 * access is that GENCGC write-protected the page.
4163 * However, if two CPUs hit a wp page near-simultaneously,
4164 * we had better not have the second one lose here if it
4165 * does this test after the first one has already set wp=0
4167 if(page_table[page_index].write_protected_cleared != 1)
4168 lose("fault in heap page not marked as write-protected");
4170 /* Don't worry, we can handle it. */
4174 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4175 * it's not just a case of the program hitting the write barrier, and
4176 * are about to let Lisp deal with it. It's basically just a
4177 * convenient place to set a gdb breakpoint. */
4179 unhandled_sigmemoryfault()
4182 void gc_alloc_update_all_page_tables(void)
4184 /* Flush the alloc regions updating the tables. */
4187 gc_alloc_update_page_tables(0, &th->alloc_region);
4188 gc_alloc_update_page_tables(1, &unboxed_region);
4189 gc_alloc_update_page_tables(0, &boxed_region);
4192 gc_set_region_empty(struct alloc_region *region)
4194 region->first_page = 0;
4195 region->last_page = -1;
4196 region->start_addr = page_address(0);
4197 region->free_pointer = page_address(0);
4198 region->end_addr = page_address(0);