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"
42 #include "gc-internal.h"
44 #include "genesis/vector.h"
45 #include "genesis/weak-pointer.h"
46 #include "genesis/simple-fun.h"
47 #include "genesis/hash-table.h"
49 /* forward declarations */
50 long gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed);
51 static void gencgc_pickup_dynamic(void);
58 /* the number of actual generations. (The number of 'struct
59 * generation' objects is one more than this, because one object
60 * serves as scratch when GC'ing.) */
61 #define NUM_GENERATIONS 6
63 /* Should we use page protection to help avoid the scavenging of pages
64 * that don't have pointers to younger generations? */
65 boolean enable_page_protection = 1;
67 /* Should we unmap a page and re-mmap it to have it zero filled? */
68 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
69 /* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
70 * so don't unmap there.
72 * The CMU CL comment didn't specify a version, but was probably an
73 * old version of FreeBSD (pre-4.0), so this might no longer be true.
74 * OTOH, if it is true, this behavior might exist on OpenBSD too, so
75 * for now we don't unmap there either. -- WHN 2001-04-07 */
76 boolean gencgc_unmap_zero = 0;
78 boolean gencgc_unmap_zero = 1;
81 /* the minimum size (in bytes) for a large object*/
82 unsigned large_object_size = 4 * PAGE_BYTES;
91 /* the verbosity level. All non-error messages are disabled at level 0;
92 * and only a few rare messages are printed at level 1. */
94 unsigned gencgc_verbose = 1;
96 unsigned gencgc_verbose = 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;
154 #if N_WORD_BITS == 32
155 #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
156 #elif N_WORD_BITS == 64
157 #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
160 /* Calculate the start address for the given page number. */
162 page_address(long page_num)
164 return (heap_base + (page_num * PAGE_BYTES));
167 /* Find the page index within the page_table for the given
168 * address. Return -1 on failure. */
170 find_page_index(void *addr)
172 long index = addr-heap_base;
175 index = ((unsigned long)index)/PAGE_BYTES;
176 if (index < NUM_PAGES)
183 /* a structure to hold the state of a generation */
186 /* the first page that gc_alloc() checks on its next call */
187 long alloc_start_page;
189 /* the first page that gc_alloc_unboxed() checks on its next call */
190 long alloc_unboxed_start_page;
192 /* the first page that gc_alloc_large (boxed) considers on its next
193 * call. (Although it always allocates after the boxed_region.) */
194 long alloc_large_start_page;
196 /* the first page that gc_alloc_large (unboxed) considers on its
197 * next call. (Although it always allocates after the
198 * current_unboxed_region.) */
199 long alloc_large_unboxed_start_page;
201 /* the bytes allocated to this generation */
202 long bytes_allocated;
204 /* the number of bytes at which to trigger a GC */
207 /* to calculate a new level for gc_trigger */
208 long bytes_consed_between_gc;
210 /* the number of GCs since the last raise */
213 /* the average age after which a GC will raise objects to the
217 /* the cumulative sum of the bytes allocated to this generation. It is
218 * cleared after a GC on this generations, and update before new
219 * objects are added from a GC of a younger generation. Dividing by
220 * the bytes_allocated will give the average age of the memory in
221 * this generation since its last GC. */
222 long cum_sum_bytes_allocated;
224 /* a minimum average memory age before a GC will occur helps
225 * prevent a GC when a large number of new live objects have been
226 * added, in which case a GC could be a waste of time */
227 double min_av_mem_age;
229 /* the number of actual generations. (The number of 'struct
230 * generation' objects is one more than this, because one object
231 * serves as scratch when GC'ing.) */
232 #define NUM_GENERATIONS 6
234 /* an array of generation structures. There needs to be one more
235 * generation structure than actual generations as the oldest
236 * generation is temporarily raised then lowered. */
237 struct generation generations[NUM_GENERATIONS+1];
239 /* the oldest generation that is will currently be GCed by default.
240 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
242 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
244 * Setting this to 0 effectively disables the generational nature of
245 * the GC. In some applications generational GC may not be useful
246 * because there are no long-lived objects.
248 * An intermediate value could be handy after moving long-lived data
249 * into an older generation so an unnecessary GC of this long-lived
250 * data can be avoided. */
251 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
253 /* The maximum free page in the heap is maintained and used to update
254 * ALLOCATION_POINTER which is used by the room function to limit its
255 * search of the heap. XX Gencgc obviously needs to be better
256 * integrated with the Lisp code. */
257 static long last_free_page;
259 /* This lock is to prevent multiple threads from simultaneously
260 * allocating new regions which overlap each other. Note that the
261 * majority of GC is single-threaded, but alloc() may be called from
262 * >1 thread at a time and must be thread-safe. This lock must be
263 * seized before all accesses to generations[] or to parts of
264 * page_table[] that other threads may want to see */
266 static lispobj free_pages_lock=0;
270 * miscellaneous heap functions
273 /* Count the number of pages which are write-protected within the
274 * given generation. */
276 count_write_protect_generation_pages(int generation)
281 for (i = 0; i < last_free_page; i++)
282 if ((page_table[i].allocated != FREE_PAGE_FLAG)
283 && (page_table[i].gen == generation)
284 && (page_table[i].write_protected == 1))
289 /* Count the number of pages within the given generation. */
291 count_generation_pages(int generation)
296 for (i = 0; i < last_free_page; i++)
297 if ((page_table[i].allocated != 0)
298 && (page_table[i].gen == generation))
305 count_dont_move_pages(void)
309 for (i = 0; i < last_free_page; i++) {
310 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
318 /* Work through the pages and add up the number of bytes used for the
319 * given generation. */
321 count_generation_bytes_allocated (int gen)
325 for (i = 0; i < last_free_page; i++) {
326 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
327 result += page_table[i].bytes_used;
332 /* Return the average age of the memory in a generation. */
334 gen_av_mem_age(int gen)
336 if (generations[gen].bytes_allocated == 0)
340 ((double)generations[gen].cum_sum_bytes_allocated)
341 / ((double)generations[gen].bytes_allocated);
344 void fpu_save(int *); /* defined in x86-assem.S */
345 void fpu_restore(int *); /* defined in x86-assem.S */
346 /* The verbose argument controls how much to print: 0 for normal
347 * level of detail; 1 for debugging. */
349 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
354 /* This code uses the FP instructions which may be set up for Lisp
355 * so they need to be saved and reset for C. */
358 /* number of generations to print */
360 gens = NUM_GENERATIONS+1;
362 gens = NUM_GENERATIONS;
364 /* Print the heap stats. */
366 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
368 for (i = 0; i < gens; i++) {
372 int large_boxed_cnt = 0;
373 int large_unboxed_cnt = 0;
376 for (j = 0; j < last_free_page; j++)
377 if (page_table[j].gen == i) {
379 /* Count the number of boxed pages within the given
381 if (page_table[j].allocated & BOXED_PAGE_FLAG) {
382 if (page_table[j].large_object)
387 if(page_table[j].dont_move) pinned_cnt++;
388 /* Count the number of unboxed pages within the given
390 if (page_table[j].allocated & UNBOXED_PAGE_FLAG) {
391 if (page_table[j].large_object)
398 gc_assert(generations[i].bytes_allocated
399 == count_generation_bytes_allocated(i));
401 " %1d: %5d %5d %5d %5d %5d %8ld %5ld %8ld %4ld %3d %7.4f\n",
403 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
405 generations[i].bytes_allocated,
406 (count_generation_pages(i)*PAGE_BYTES
407 - generations[i].bytes_allocated),
408 generations[i].gc_trigger,
409 count_write_protect_generation_pages(i),
410 generations[i].num_gc,
413 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
415 fpu_restore(fpu_state);
419 * allocation routines
423 * To support quick and inline allocation, regions of memory can be
424 * allocated and then allocated from with just a free pointer and a
425 * check against an end address.
427 * Since objects can be allocated to spaces with different properties
428 * e.g. boxed/unboxed, generation, ages; there may need to be many
429 * allocation regions.
431 * Each allocation region may start within a partly used page. Many
432 * features of memory use are noted on a page wise basis, e.g. the
433 * generation; so if a region starts within an existing allocated page
434 * it must be consistent with this page.
436 * During the scavenging of the newspace, objects will be transported
437 * into an allocation region, and pointers updated to point to this
438 * allocation region. It is possible that these pointers will be
439 * scavenged again before the allocation region is closed, e.g. due to
440 * trans_list which jumps all over the place to cleanup the list. It
441 * is important to be able to determine properties of all objects
442 * pointed to when scavenging, e.g to detect pointers to the oldspace.
443 * Thus it's important that the allocation regions have the correct
444 * properties set when allocated, and not just set when closed. The
445 * region allocation routines return regions with the specified
446 * properties, and grab all the pages, setting their properties
447 * appropriately, except that the amount used is not known.
449 * These regions are used to support quicker allocation using just a
450 * free pointer. The actual space used by the region is not reflected
451 * in the pages tables until it is closed. It can't be scavenged until
454 * When finished with the region it should be closed, which will
455 * update the page tables for the actual space used returning unused
456 * space. Further it may be noted in the new regions which is
457 * necessary when scavenging the newspace.
459 * Large objects may be allocated directly without an allocation
460 * region, the page tables are updated immediately.
462 * Unboxed objects don't contain pointers to other objects and so
463 * don't need scavenging. Further they can't contain pointers to
464 * younger generations so WP is not needed. By allocating pages to
465 * unboxed objects the whole page never needs scavenging or
466 * write-protecting. */
468 /* We are only using two regions at present. Both are for the current
469 * newspace generation. */
470 struct alloc_region boxed_region;
471 struct alloc_region unboxed_region;
473 /* The generation currently being allocated to. */
474 static int gc_alloc_generation;
476 /* Find a new region with room for at least the given number of bytes.
478 * It starts looking at the current generation's alloc_start_page. So
479 * may pick up from the previous region if there is enough space. This
480 * keeps the allocation contiguous when scavenging the newspace.
482 * The alloc_region should have been closed by a call to
483 * gc_alloc_update_page_tables(), and will thus be in an empty state.
485 * To assist the scavenging functions write-protected pages are not
486 * used. Free pages should not be write-protected.
488 * It is critical to the conservative GC that the start of regions be
489 * known. To help achieve this only small regions are allocated at a
492 * During scavenging, pointers may be found to within the current
493 * region and the page generation must be set so that pointers to the
494 * from space can be recognized. Therefore the generation of pages in
495 * the region are set to gc_alloc_generation. To prevent another
496 * allocation call using the same pages, all the pages in the region
497 * are allocated, although they will initially be empty.
500 gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
509 "/alloc_new_region for %d bytes from gen %d\n",
510 nbytes, gc_alloc_generation));
513 /* Check that the region is in a reset state. */
514 gc_assert((alloc_region->first_page == 0)
515 && (alloc_region->last_page == -1)
516 && (alloc_region->free_pointer == alloc_region->end_addr));
517 get_spinlock(&free_pages_lock,(long) alloc_region);
520 generations[gc_alloc_generation].alloc_unboxed_start_page;
523 generations[gc_alloc_generation].alloc_start_page;
525 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
526 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
527 + PAGE_BYTES*(last_page-first_page);
529 /* Set up the alloc_region. */
530 alloc_region->first_page = first_page;
531 alloc_region->last_page = last_page;
532 alloc_region->start_addr = page_table[first_page].bytes_used
533 + page_address(first_page);
534 alloc_region->free_pointer = alloc_region->start_addr;
535 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
537 /* Set up the pages. */
539 /* The first page may have already been in use. */
540 if (page_table[first_page].bytes_used == 0) {
542 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
544 page_table[first_page].allocated = BOXED_PAGE_FLAG;
545 page_table[first_page].gen = gc_alloc_generation;
546 page_table[first_page].large_object = 0;
547 page_table[first_page].first_object_offset = 0;
551 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
553 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
554 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
556 gc_assert(page_table[first_page].gen == gc_alloc_generation);
557 gc_assert(page_table[first_page].large_object == 0);
559 for (i = first_page+1; i <= last_page; i++) {
561 page_table[i].allocated = UNBOXED_PAGE_FLAG;
563 page_table[i].allocated = BOXED_PAGE_FLAG;
564 page_table[i].gen = gc_alloc_generation;
565 page_table[i].large_object = 0;
566 /* This may not be necessary for unboxed regions (think it was
568 page_table[i].first_object_offset =
569 alloc_region->start_addr - page_address(i);
570 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
572 /* Bump up last_free_page. */
573 if (last_page+1 > last_free_page) {
574 last_free_page = last_page+1;
575 SetSymbolValue(ALLOCATION_POINTER,
576 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
579 release_spinlock(&free_pages_lock);
581 /* we can do this after releasing free_pages_lock */
582 if (gencgc_zero_check) {
584 for (p = (long *)alloc_region->start_addr;
585 p < (long *)alloc_region->end_addr; p++) {
587 /* KLUDGE: It would be nice to use %lx and explicit casts
588 * (long) in code like this, so that it is less likely to
589 * break randomly when running on a machine with different
590 * word sizes. -- WHN 19991129 */
591 lose("The new region at %x is not zero.", p);
598 /* If the record_new_objects flag is 2 then all new regions created
601 * If it's 1 then then it is only recorded if the first page of the
602 * current region is <= new_areas_ignore_page. This helps avoid
603 * unnecessary recording when doing full scavenge pass.
605 * The new_object structure holds the page, byte offset, and size of
606 * new regions of objects. Each new area is placed in the array of
607 * these structures pointer to by new_areas. new_areas_index holds the
608 * offset into new_areas.
610 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
611 * later code must detect this and handle it, probably by doing a full
612 * scavenge of a generation. */
613 #define NUM_NEW_AREAS 512
614 static int record_new_objects = 0;
615 static long new_areas_ignore_page;
621 static struct new_area (*new_areas)[];
622 static long new_areas_index;
625 /* Add a new area to new_areas. */
627 add_new_area(long first_page, long offset, long size)
629 unsigned new_area_start,c;
632 /* Ignore if full. */
633 if (new_areas_index >= NUM_NEW_AREAS)
636 switch (record_new_objects) {
640 if (first_page > new_areas_ignore_page)
649 new_area_start = PAGE_BYTES*first_page + offset;
651 /* Search backwards for a prior area that this follows from. If
652 found this will save adding a new area. */
653 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
655 PAGE_BYTES*((*new_areas)[i].page)
656 + (*new_areas)[i].offset
657 + (*new_areas)[i].size;
659 "/add_new_area S1 %d %d %d %d\n",
660 i, c, new_area_start, area_end));*/
661 if (new_area_start == area_end) {
663 "/adding to [%d] %d %d %d with %d %d %d:\n",
665 (*new_areas)[i].page,
666 (*new_areas)[i].offset,
667 (*new_areas)[i].size,
671 (*new_areas)[i].size += size;
676 (*new_areas)[new_areas_index].page = first_page;
677 (*new_areas)[new_areas_index].offset = offset;
678 (*new_areas)[new_areas_index].size = size;
680 "/new_area %d page %d offset %d size %d\n",
681 new_areas_index, first_page, offset, size));*/
684 /* Note the max new_areas used. */
685 if (new_areas_index > max_new_areas)
686 max_new_areas = new_areas_index;
689 /* Update the tables for the alloc_region. The region may be added to
692 * When done the alloc_region is set up so that the next quick alloc
693 * will fail safely and thus a new region will be allocated. Further
694 * it is safe to try to re-update the page table of this reset
697 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
703 long orig_first_page_bytes_used;
708 first_page = alloc_region->first_page;
710 /* Catch an unused alloc_region. */
711 if ((first_page == 0) && (alloc_region->last_page == -1))
714 next_page = first_page+1;
716 get_spinlock(&free_pages_lock,(long) alloc_region);
717 if (alloc_region->free_pointer != alloc_region->start_addr) {
718 /* some bytes were allocated in the region */
719 orig_first_page_bytes_used = page_table[first_page].bytes_used;
721 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
723 /* All the pages used need to be updated */
725 /* Update the first page. */
727 /* If the page was free then set up the gen, and
728 * first_object_offset. */
729 if (page_table[first_page].bytes_used == 0)
730 gc_assert(page_table[first_page].first_object_offset == 0);
731 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
734 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
736 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
737 gc_assert(page_table[first_page].gen == gc_alloc_generation);
738 gc_assert(page_table[first_page].large_object == 0);
742 /* Calculate the number of bytes used in this page. This is not
743 * always the number of new bytes, unless it was free. */
745 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
746 bytes_used = PAGE_BYTES;
749 page_table[first_page].bytes_used = bytes_used;
750 byte_cnt += bytes_used;
753 /* All the rest of the pages should be free. We need to set their
754 * first_object_offset pointer to the start of the region, and set
757 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
759 gc_assert(page_table[next_page].allocated==UNBOXED_PAGE_FLAG);
761 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
762 gc_assert(page_table[next_page].bytes_used == 0);
763 gc_assert(page_table[next_page].gen == gc_alloc_generation);
764 gc_assert(page_table[next_page].large_object == 0);
766 gc_assert(page_table[next_page].first_object_offset ==
767 alloc_region->start_addr - page_address(next_page));
769 /* Calculate the number of bytes used in this page. */
771 if ((bytes_used = (alloc_region->free_pointer
772 - page_address(next_page)))>PAGE_BYTES) {
773 bytes_used = PAGE_BYTES;
776 page_table[next_page].bytes_used = bytes_used;
777 byte_cnt += bytes_used;
782 region_size = alloc_region->free_pointer - alloc_region->start_addr;
783 bytes_allocated += region_size;
784 generations[gc_alloc_generation].bytes_allocated += region_size;
786 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
788 /* Set the generations alloc restart page to the last page of
791 generations[gc_alloc_generation].alloc_unboxed_start_page =
794 generations[gc_alloc_generation].alloc_start_page = next_page-1;
796 /* Add the region to the new_areas if requested. */
798 add_new_area(first_page,orig_first_page_bytes_used, region_size);
802 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
804 gc_alloc_generation));
807 /* There are no bytes allocated. Unallocate the first_page if
808 * there are 0 bytes_used. */
809 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
810 if (page_table[first_page].bytes_used == 0)
811 page_table[first_page].allocated = FREE_PAGE_FLAG;
814 /* Unallocate any unused pages. */
815 while (next_page <= alloc_region->last_page) {
816 gc_assert(page_table[next_page].bytes_used == 0);
817 page_table[next_page].allocated = FREE_PAGE_FLAG;
820 release_spinlock(&free_pages_lock);
821 /* alloc_region is per-thread, we're ok to do this unlocked */
822 gc_set_region_empty(alloc_region);
825 static inline void *gc_quick_alloc(long nbytes);
827 /* Allocate a possibly large object. */
829 gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
833 long orig_first_page_bytes_used;
839 get_spinlock(&free_pages_lock,(long) alloc_region);
843 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
845 first_page = generations[gc_alloc_generation].alloc_large_start_page;
847 if (first_page <= alloc_region->last_page) {
848 first_page = alloc_region->last_page+1;
851 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
853 gc_assert(first_page > alloc_region->last_page);
855 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
858 generations[gc_alloc_generation].alloc_large_start_page = last_page;
860 /* Set up the pages. */
861 orig_first_page_bytes_used = page_table[first_page].bytes_used;
863 /* If the first page was free then set up the gen, and
864 * first_object_offset. */
865 if (page_table[first_page].bytes_used == 0) {
867 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
869 page_table[first_page].allocated = BOXED_PAGE_FLAG;
870 page_table[first_page].gen = gc_alloc_generation;
871 page_table[first_page].first_object_offset = 0;
872 page_table[first_page].large_object = 1;
876 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
878 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
879 gc_assert(page_table[first_page].gen == gc_alloc_generation);
880 gc_assert(page_table[first_page].large_object == 1);
884 /* Calc. the number of bytes used in this page. This is not
885 * always the number of new bytes, unless it was free. */
887 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
888 bytes_used = PAGE_BYTES;
891 page_table[first_page].bytes_used = bytes_used;
892 byte_cnt += bytes_used;
894 next_page = first_page+1;
896 /* All the rest of the pages should be free. We need to set their
897 * first_object_offset pointer to the start of the region, and
898 * set the bytes_used. */
900 gc_assert(page_table[next_page].allocated == FREE_PAGE_FLAG);
901 gc_assert(page_table[next_page].bytes_used == 0);
903 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
905 page_table[next_page].allocated = BOXED_PAGE_FLAG;
906 page_table[next_page].gen = gc_alloc_generation;
907 page_table[next_page].large_object = 1;
909 page_table[next_page].first_object_offset =
910 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
912 /* Calculate the number of bytes used in this page. */
914 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
915 bytes_used = PAGE_BYTES;
918 page_table[next_page].bytes_used = bytes_used;
919 page_table[next_page].write_protected=0;
920 page_table[next_page].dont_move=0;
921 byte_cnt += bytes_used;
925 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
927 bytes_allocated += nbytes;
928 generations[gc_alloc_generation].bytes_allocated += nbytes;
930 /* Add the region to the new_areas if requested. */
932 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
934 /* Bump up last_free_page */
935 if (last_page+1 > last_free_page) {
936 last_free_page = last_page+1;
937 SetSymbolValue(ALLOCATION_POINTER,
938 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
940 release_spinlock(&free_pages_lock);
942 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
946 gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed)
951 long restart_page=*restart_page_ptr;
954 long large_p=(nbytes>=large_object_size);
955 gc_assert(free_pages_lock);
957 /* Search for a contiguous free space of at least nbytes. If it's
958 * a large object then align it on a page boundary by searching
959 * for a free page. */
962 first_page = restart_page;
964 while ((first_page < NUM_PAGES)
965 && (page_table[first_page].allocated != FREE_PAGE_FLAG))
968 while (first_page < NUM_PAGES) {
969 if(page_table[first_page].allocated == FREE_PAGE_FLAG)
971 if((page_table[first_page].allocated ==
972 (unboxed ? UNBOXED_PAGE_FLAG : BOXED_PAGE_FLAG)) &&
973 (page_table[first_page].large_object == 0) &&
974 (page_table[first_page].gen == gc_alloc_generation) &&
975 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
976 (page_table[first_page].write_protected == 0) &&
977 (page_table[first_page].dont_move == 0)) {
983 if (first_page >= NUM_PAGES) {
985 "Argh! gc_find_free_space failed (first_page), nbytes=%ld.\n",
987 print_generation_stats(1);
991 gc_assert(page_table[first_page].write_protected == 0);
993 last_page = first_page;
994 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
996 while (((bytes_found < nbytes)
997 || (!large_p && (num_pages < 2)))
998 && (last_page < (NUM_PAGES-1))
999 && (page_table[last_page+1].allocated == FREE_PAGE_FLAG)) {
1002 bytes_found += PAGE_BYTES;
1003 gc_assert(page_table[last_page].write_protected == 0);
1006 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
1007 + PAGE_BYTES*(last_page-first_page);
1009 gc_assert(bytes_found == region_size);
1010 restart_page = last_page + 1;
1011 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
1013 /* Check for a failure */
1014 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
1016 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%ld.\n",
1018 print_generation_stats(1);
1021 *restart_page_ptr=first_page;
1025 /* Allocate bytes. All the rest of the special-purpose allocation
1026 * functions will eventually call this */
1029 gc_alloc_with_region(long nbytes,int unboxed_p, struct alloc_region *my_region,
1032 void *new_free_pointer;
1034 if(nbytes>=large_object_size)
1035 return gc_alloc_large(nbytes,unboxed_p,my_region);
1037 /* Check whether there is room in the current alloc region. */
1038 new_free_pointer = my_region->free_pointer + nbytes;
1040 /* fprintf(stderr, "alloc %d bytes from %p to %p\n", nbytes,
1041 my_region->free_pointer, new_free_pointer); */
1043 if (new_free_pointer <= my_region->end_addr) {
1044 /* If so then allocate from the current alloc region. */
1045 void *new_obj = my_region->free_pointer;
1046 my_region->free_pointer = new_free_pointer;
1048 /* Unless a `quick' alloc was requested, check whether the
1049 alloc region is almost empty. */
1051 (my_region->end_addr - my_region->free_pointer) <= 32) {
1052 /* If so, finished with the current region. */
1053 gc_alloc_update_page_tables(unboxed_p, my_region);
1054 /* Set up a new region. */
1055 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1058 return((void *)new_obj);
1061 /* Else not enough free space in the current region: retry with a
1064 gc_alloc_update_page_tables(unboxed_p, my_region);
1065 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1066 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1069 /* these are only used during GC: all allocation from the mutator calls
1070 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1074 gc_general_alloc(long nbytes,int unboxed_p,int quick_p)
1076 struct alloc_region *my_region =
1077 unboxed_p ? &unboxed_region : &boxed_region;
1078 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1081 static inline void *
1082 gc_quick_alloc(long nbytes)
1084 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1087 static inline void *
1088 gc_quick_alloc_large(long nbytes)
1090 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1093 static inline void *
1094 gc_alloc_unboxed(long nbytes)
1096 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1099 static inline void *
1100 gc_quick_alloc_unboxed(long nbytes)
1102 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1105 static inline void *
1106 gc_quick_alloc_large_unboxed(long nbytes)
1108 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1112 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1115 extern long (*scavtab[256])(lispobj *where, lispobj object);
1116 extern lispobj (*transother[256])(lispobj object);
1117 extern long (*sizetab[256])(lispobj *where);
1119 /* Copy a large boxed object. If the object is in a large object
1120 * region then it is simply promoted, else it is copied. If it's large
1121 * enough then it's copied to a large object region.
1123 * Vectors may have shrunk. If the object is not copied the space
1124 * needs to be reclaimed, and the page_tables corrected. */
1126 copy_large_object(lispobj object, long nwords)
1132 gc_assert(is_lisp_pointer(object));
1133 gc_assert(from_space_p(object));
1134 gc_assert((nwords & 0x01) == 0);
1137 /* Check whether it's in a large object region. */
1138 first_page = find_page_index((void *)object);
1139 gc_assert(first_page >= 0);
1141 if (page_table[first_page].large_object) {
1143 /* Promote the object. */
1145 long remaining_bytes;
1148 long old_bytes_used;
1150 /* Note: Any page write-protection must be removed, else a
1151 * later scavenge_newspace may incorrectly not scavenge these
1152 * pages. This would not be necessary if they are added to the
1153 * new areas, but let's do it for them all (they'll probably
1154 * be written anyway?). */
1156 gc_assert(page_table[first_page].first_object_offset == 0);
1158 next_page = first_page;
1159 remaining_bytes = nwords*N_WORD_BYTES;
1160 while (remaining_bytes > PAGE_BYTES) {
1161 gc_assert(page_table[next_page].gen == from_space);
1162 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1163 gc_assert(page_table[next_page].large_object);
1164 gc_assert(page_table[next_page].first_object_offset==
1165 -PAGE_BYTES*(next_page-first_page));
1166 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1168 page_table[next_page].gen = new_space;
1170 /* Remove any write-protection. We should be able to rely
1171 * on the write-protect flag to avoid redundant calls. */
1172 if (page_table[next_page].write_protected) {
1173 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1174 page_table[next_page].write_protected = 0;
1176 remaining_bytes -= PAGE_BYTES;
1180 /* Now only one page remains, but the object may have shrunk
1181 * so there may be more unused pages which will be freed. */
1183 /* The object may have shrunk but shouldn't have grown. */
1184 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1186 page_table[next_page].gen = new_space;
1187 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1189 /* Adjust the bytes_used. */
1190 old_bytes_used = page_table[next_page].bytes_used;
1191 page_table[next_page].bytes_used = remaining_bytes;
1193 bytes_freed = old_bytes_used - remaining_bytes;
1195 /* Free any remaining pages; needs care. */
1197 while ((old_bytes_used == PAGE_BYTES) &&
1198 (page_table[next_page].gen == from_space) &&
1199 (page_table[next_page].allocated == BOXED_PAGE_FLAG) &&
1200 page_table[next_page].large_object &&
1201 (page_table[next_page].first_object_offset ==
1202 -(next_page - first_page)*PAGE_BYTES)) {
1203 /* Checks out OK, free the page. Don't need to bother zeroing
1204 * pages as this should have been done before shrinking the
1205 * object. These pages shouldn't be write-protected as they
1206 * should be zero filled. */
1207 gc_assert(page_table[next_page].write_protected == 0);
1209 old_bytes_used = page_table[next_page].bytes_used;
1210 page_table[next_page].allocated = FREE_PAGE_FLAG;
1211 page_table[next_page].bytes_used = 0;
1212 bytes_freed += old_bytes_used;
1216 generations[from_space].bytes_allocated -= N_WORD_BYTES*nwords +
1218 generations[new_space].bytes_allocated += N_WORD_BYTES*nwords;
1219 bytes_allocated -= bytes_freed;
1221 /* Add the region to the new_areas if requested. */
1222 add_new_area(first_page,0,nwords*N_WORD_BYTES);
1226 /* Get tag of object. */
1227 tag = lowtag_of(object);
1229 /* Allocate space. */
1230 new = gc_quick_alloc_large(nwords*N_WORD_BYTES);
1232 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1234 /* Return Lisp pointer of new object. */
1235 return ((lispobj) new) | tag;
1239 /* to copy unboxed objects */
1241 copy_unboxed_object(lispobj object, long nwords)
1246 gc_assert(is_lisp_pointer(object));
1247 gc_assert(from_space_p(object));
1248 gc_assert((nwords & 0x01) == 0);
1250 /* Get tag of object. */
1251 tag = lowtag_of(object);
1253 /* Allocate space. */
1254 new = gc_quick_alloc_unboxed(nwords*N_WORD_BYTES);
1256 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1258 /* Return Lisp pointer of new object. */
1259 return ((lispobj) new) | tag;
1262 /* to copy large unboxed objects
1264 * If the object is in a large object region then it is simply
1265 * promoted, else it is copied. If it's large enough then it's copied
1266 * to a large object region.
1268 * Bignums and vectors may have shrunk. If the object is not copied
1269 * the space needs to be reclaimed, and the page_tables corrected.
1271 * KLUDGE: There's a lot of cut-and-paste duplication between this
1272 * function and copy_large_object(..). -- WHN 20000619 */
1274 copy_large_unboxed_object(lispobj object, long nwords)
1280 gc_assert(is_lisp_pointer(object));
1281 gc_assert(from_space_p(object));
1282 gc_assert((nwords & 0x01) == 0);
1284 if ((nwords > 1024*1024) && gencgc_verbose)
1285 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*N_WORD_BYTES));
1287 /* Check whether it's a large object. */
1288 first_page = find_page_index((void *)object);
1289 gc_assert(first_page >= 0);
1291 if (page_table[first_page].large_object) {
1292 /* Promote the object. Note: Unboxed objects may have been
1293 * allocated to a BOXED region so it may be necessary to
1294 * change the region to UNBOXED. */
1295 long remaining_bytes;
1298 long old_bytes_used;
1300 gc_assert(page_table[first_page].first_object_offset == 0);
1302 next_page = first_page;
1303 remaining_bytes = nwords*N_WORD_BYTES;
1304 while (remaining_bytes > PAGE_BYTES) {
1305 gc_assert(page_table[next_page].gen == from_space);
1306 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1307 || (page_table[next_page].allocated == BOXED_PAGE_FLAG));
1308 gc_assert(page_table[next_page].large_object);
1309 gc_assert(page_table[next_page].first_object_offset==
1310 -PAGE_BYTES*(next_page-first_page));
1311 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1313 page_table[next_page].gen = new_space;
1314 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1315 remaining_bytes -= PAGE_BYTES;
1319 /* Now only one page remains, but the object may have shrunk so
1320 * there may be more unused pages which will be freed. */
1322 /* Object may have shrunk but shouldn't have grown - check. */
1323 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1325 page_table[next_page].gen = new_space;
1326 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1328 /* Adjust the bytes_used. */
1329 old_bytes_used = page_table[next_page].bytes_used;
1330 page_table[next_page].bytes_used = remaining_bytes;
1332 bytes_freed = old_bytes_used - remaining_bytes;
1334 /* Free any remaining pages; needs care. */
1336 while ((old_bytes_used == PAGE_BYTES) &&
1337 (page_table[next_page].gen == from_space) &&
1338 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1339 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
1340 page_table[next_page].large_object &&
1341 (page_table[next_page].first_object_offset ==
1342 -(next_page - first_page)*PAGE_BYTES)) {
1343 /* Checks out OK, free the page. Don't need to both zeroing
1344 * pages as this should have been done before shrinking the
1345 * object. These pages shouldn't be write-protected, even if
1346 * boxed they should be zero filled. */
1347 gc_assert(page_table[next_page].write_protected == 0);
1349 old_bytes_used = page_table[next_page].bytes_used;
1350 page_table[next_page].allocated = FREE_PAGE_FLAG;
1351 page_table[next_page].bytes_used = 0;
1352 bytes_freed += old_bytes_used;
1356 if ((bytes_freed > 0) && gencgc_verbose)
1358 "/copy_large_unboxed bytes_freed=%d\n",
1361 generations[from_space].bytes_allocated -= nwords*N_WORD_BYTES + bytes_freed;
1362 generations[new_space].bytes_allocated += nwords*N_WORD_BYTES;
1363 bytes_allocated -= bytes_freed;
1368 /* Get tag of object. */
1369 tag = lowtag_of(object);
1371 /* Allocate space. */
1372 new = gc_quick_alloc_large_unboxed(nwords*N_WORD_BYTES);
1374 /* Copy the object. */
1375 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
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 long 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*N_WORD_BYTES;
1420 constants_end_addr = (void *)code + nheader_words*N_WORD_BYTES;
1421 code_start_addr = (void *)code + nheader_words*N_WORD_BYTES;
1422 code_end_addr = (void *)code + nwords*N_WORD_BYTES;
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 long 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*N_WORD_BYTES;
1590 constants_end_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1591 code_start_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1592 code_end_addr = (void *)new_code + nwords*N_WORD_BYTES;
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) == SIMPLE_ARRAY_WORD_WIDETAG) {
1634 /* Got the fixups for the code block. Now work through the vector,
1635 and apply a fixup at each address. */
1636 long length = fixnum_value(fixups_vector->length);
1638 for (i = 0; i < length; i++) {
1639 unsigned offset = fixups_vector->data[i];
1640 /* Now check the current value of offset. */
1641 unsigned old_value =
1642 *(unsigned *)((unsigned)code_start_addr + offset);
1644 /* If it's within the old_code object then it must be an
1645 * absolute fixup (relative ones are not saved) */
1646 if ((old_value >= (unsigned)old_code)
1647 && (old_value < ((unsigned)old_code + nwords*N_WORD_BYTES)))
1648 /* So add the dispacement. */
1649 *(unsigned *)((unsigned)code_start_addr + offset) =
1650 old_value + displacement;
1652 /* It is outside the old code object so it must be a
1653 * relative fixup (absolute fixups are not saved). So
1654 * subtract the displacement. */
1655 *(unsigned *)((unsigned)code_start_addr + offset) =
1656 old_value - displacement;
1659 fprintf(stderr, "widetag of fixup vector is %d\n", widetag_of(fixups_vector->header));
1662 /* Check for possible errors. */
1663 if (check_code_fixups) {
1664 sniff_code_object(new_code,displacement);
1670 trans_boxed_large(lispobj object)
1673 unsigned long length;
1675 gc_assert(is_lisp_pointer(object));
1677 header = *((lispobj *) native_pointer(object));
1678 length = HeaderValue(header) + 1;
1679 length = CEILING(length, 2);
1681 return copy_large_object(object, length);
1684 /* Doesn't seem to be used, delete it after the grace period. */
1687 trans_unboxed_large(lispobj object)
1690 unsigned long length;
1693 gc_assert(is_lisp_pointer(object));
1695 header = *((lispobj *) native_pointer(object));
1696 length = HeaderValue(header) + 1;
1697 length = CEILING(length, 2);
1699 return copy_large_unboxed_object(object, length);
1705 * vector-like objects
1709 /* FIXME: What does this mean? */
1710 int gencgc_hash = 1;
1713 scav_vector(lispobj *where, lispobj object)
1715 unsigned long kv_length;
1717 unsigned long length = 0; /* (0 = dummy to stop GCC warning) */
1718 struct hash_table *hash_table;
1719 lispobj empty_symbol;
1720 unsigned long *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1721 unsigned long *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1722 unsigned long *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1724 unsigned next_vector_length = 0;
1726 /* FIXME: A comment explaining this would be nice. It looks as
1727 * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
1728 * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
1729 if (HeaderValue(object) != subtype_VectorValidHashing)
1733 /* This is set for backward compatibility. FIXME: Do we need
1736 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
1740 kv_length = fixnum_value(where[1]);
1741 kv_vector = where + 2; /* Skip the header and length. */
1742 /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
1744 /* Scavenge element 0, which may be a hash-table structure. */
1745 scavenge(where+2, 1);
1746 if (!is_lisp_pointer(where[2])) {
1747 lose("no pointer at %x in hash table", where[2]);
1749 hash_table = (struct hash_table *)native_pointer(where[2]);
1750 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1751 if (widetag_of(hash_table->header) != INSTANCE_HEADER_WIDETAG) {
1752 lose("hash table not instance (%x at %x)",
1757 /* Scavenge element 1, which should be some internal symbol that
1758 * the hash table code reserves for marking empty slots. */
1759 scavenge(where+3, 1);
1760 if (!is_lisp_pointer(where[3])) {
1761 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1763 empty_symbol = where[3];
1764 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1765 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1766 SYMBOL_HEADER_WIDETAG) {
1767 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1768 *(lispobj *)native_pointer(empty_symbol));
1771 /* Scavenge hash table, which will fix the positions of the other
1772 * needed objects. */
1773 scavenge((lispobj *)hash_table,
1774 sizeof(struct hash_table) / sizeof(lispobj));
1776 /* Cross-check the kv_vector. */
1777 if (where != (lispobj *)native_pointer(hash_table->table)) {
1778 lose("hash_table table!=this table %x", hash_table->table);
1782 weak_p_obj = hash_table->weak_p;
1786 lispobj index_vector_obj = hash_table->index_vector;
1788 if (is_lisp_pointer(index_vector_obj) &&
1789 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1790 SIMPLE_ARRAY_WORD_WIDETAG)) {
1792 ((unsigned long *)native_pointer(index_vector_obj)) + 2;
1793 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1794 length = fixnum_value(((lispobj *)native_pointer(index_vector_obj))[1]);
1795 /*FSHOW((stderr, "/length = %d\n", length));*/
1797 lose("invalid index_vector %x", index_vector_obj);
1803 lispobj next_vector_obj = hash_table->next_vector;
1805 if (is_lisp_pointer(next_vector_obj) &&
1806 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1807 SIMPLE_ARRAY_WORD_WIDETAG)) {
1808 next_vector = ((unsigned long *)native_pointer(next_vector_obj)) + 2;
1809 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1810 next_vector_length = fixnum_value(((lispobj *)native_pointer(next_vector_obj))[1]);
1811 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1813 lose("invalid next_vector %x", next_vector_obj);
1817 /* maybe hash vector */
1819 lispobj hash_vector_obj = hash_table->hash_vector;
1821 if (is_lisp_pointer(hash_vector_obj) &&
1822 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj)) ==
1823 SIMPLE_ARRAY_WORD_WIDETAG)){
1825 ((unsigned long *)native_pointer(hash_vector_obj)) + 2;
1826 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1827 gc_assert(fixnum_value(((lispobj *)native_pointer(hash_vector_obj))[1])
1828 == next_vector_length);
1831 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1835 /* These lengths could be different as the index_vector can be a
1836 * different length from the others, a larger index_vector could help
1837 * reduce collisions. */
1838 gc_assert(next_vector_length*2 == kv_length);
1840 /* now all set up.. */
1842 /* Work through the KV vector. */
1845 for (i = 1; i < next_vector_length; i++) {
1846 lispobj old_key = kv_vector[2*i];
1848 #if N_WORD_BITS == 32
1849 unsigned long old_index = (old_key & 0x1fffffff)%length;
1850 #elif N_WORD_BITS == 64
1851 unsigned long old_index = (old_key & 0x1fffffffffffffff)%length;
1854 /* Scavenge the key and value. */
1855 scavenge(&kv_vector[2*i],2);
1857 /* Check whether the key has moved and is EQ based. */
1859 lispobj new_key = kv_vector[2*i];
1860 #if N_WORD_BITS == 32
1861 unsigned long new_index = (new_key & 0x1fffffff)%length;
1862 #elif N_WORD_BITS == 64
1863 unsigned long new_index = (new_key & 0x1fffffffffffffff)%length;
1866 if ((old_index != new_index) &&
1867 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1868 ((new_key != empty_symbol) ||
1869 (kv_vector[2*i] != empty_symbol))) {
1872 "* EQ key %d moved from %x to %x; index %d to %d\n",
1873 i, old_key, new_key, old_index, new_index));*/
1875 if (index_vector[old_index] != 0) {
1876 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1878 /* Unlink the key from the old_index chain. */
1879 if (index_vector[old_index] == i) {
1880 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1881 index_vector[old_index] = next_vector[i];
1882 /* Link it into the needing rehash chain. */
1883 next_vector[i] = fixnum_value(hash_table->needing_rehash);
1884 hash_table->needing_rehash = make_fixnum(i);
1887 unsigned prior = index_vector[old_index];
1888 unsigned next = next_vector[prior];
1890 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1893 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1896 next_vector[prior] = next_vector[next];
1897 /* Link it into the needing rehash
1900 fixnum_value(hash_table->needing_rehash);
1901 hash_table->needing_rehash = make_fixnum(next);
1906 next = next_vector[next];
1914 return (CEILING(kv_length + 2, 2));
1923 /* XX This is a hack adapted from cgc.c. These don't work too
1924 * efficiently with the gencgc as a list of the weak pointers is
1925 * maintained within the objects which causes writes to the pages. A
1926 * limited attempt is made to avoid unnecessary writes, but this needs
1928 #define WEAK_POINTER_NWORDS \
1929 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1932 scav_weak_pointer(lispobj *where, lispobj object)
1934 struct weak_pointer *wp = weak_pointers;
1935 /* Push the weak pointer onto the list of weak pointers.
1936 * Do I have to watch for duplicates? Originally this was
1937 * part of trans_weak_pointer but that didn't work in the
1938 * case where the WP was in a promoted region.
1941 /* Check whether it's already in the list. */
1942 while (wp != NULL) {
1943 if (wp == (struct weak_pointer*)where) {
1949 /* Add it to the start of the list. */
1950 wp = (struct weak_pointer*)where;
1951 if (wp->next != weak_pointers) {
1952 wp->next = weak_pointers;
1954 /*SHOW("avoided write to weak pointer");*/
1959 /* Do not let GC scavenge the value slot of the weak pointer.
1960 * (That is why it is a weak pointer.) */
1962 return WEAK_POINTER_NWORDS;
1967 search_read_only_space(void *pointer)
1969 lispobj *start = (lispobj *) READ_ONLY_SPACE_START;
1970 lispobj *end = (lispobj *) SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1971 if ((pointer < (void *)start) || (pointer >= (void *)end))
1973 return (gc_search_space(start,
1974 (((lispobj *)pointer)+2)-start,
1975 (lispobj *) pointer));
1979 search_static_space(void *pointer)
1981 lispobj *start = (lispobj *)STATIC_SPACE_START;
1982 lispobj *end = (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1983 if ((pointer < (void *)start) || (pointer >= (void *)end))
1985 return (gc_search_space(start,
1986 (((lispobj *)pointer)+2)-start,
1987 (lispobj *) pointer));
1990 /* a faster version for searching the dynamic space. This will work even
1991 * if the object is in a current allocation region. */
1993 search_dynamic_space(void *pointer)
1995 long page_index = find_page_index(pointer);
1998 /* The address may be invalid, so do some checks. */
1999 if ((page_index == -1) ||
2000 (page_table[page_index].allocated == FREE_PAGE_FLAG))
2002 start = (lispobj *)((void *)page_address(page_index)
2003 + page_table[page_index].first_object_offset);
2004 return (gc_search_space(start,
2005 (((lispobj *)pointer)+2)-start,
2006 (lispobj *)pointer));
2009 /* Is there any possibility that pointer is a valid Lisp object
2010 * reference, and/or something else (e.g. subroutine call return
2011 * address) which should prevent us from moving the referred-to thing?
2012 * This is called from preserve_pointers() */
2014 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2016 lispobj *start_addr;
2018 /* Find the object start address. */
2019 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2023 /* We need to allow raw pointers into Code objects for return
2024 * addresses. This will also pick up pointers to functions in code
2026 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2027 /* XXX could do some further checks here */
2031 /* If it's not a return address then it needs to be a valid Lisp
2033 if (!is_lisp_pointer((lispobj)pointer)) {
2037 /* Check that the object pointed to is consistent with the pointer
2040 switch (lowtag_of((lispobj)pointer)) {
2041 case FUN_POINTER_LOWTAG:
2042 /* Start_addr should be the enclosing code object, or a closure
2044 switch (widetag_of(*start_addr)) {
2045 case CODE_HEADER_WIDETAG:
2046 /* This case is probably caught above. */
2048 case CLOSURE_HEADER_WIDETAG:
2049 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2050 if ((unsigned)pointer !=
2051 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2055 pointer, start_addr, *start_addr));
2063 pointer, start_addr, *start_addr));
2067 case LIST_POINTER_LOWTAG:
2068 if ((unsigned)pointer !=
2069 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2073 pointer, start_addr, *start_addr));
2076 /* Is it plausible cons? */
2077 if ((is_lisp_pointer(start_addr[0])
2078 || (fixnump(start_addr[0]))
2079 || (widetag_of(start_addr[0]) == CHARACTER_WIDETAG)
2080 #if N_WORD_BITS == 64
2081 || (widetag_of(start_addr[0]) == SINGLE_FLOAT_WIDETAG)
2083 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2084 && (is_lisp_pointer(start_addr[1])
2085 || (fixnump(start_addr[1]))
2086 || (widetag_of(start_addr[1]) == CHARACTER_WIDETAG)
2087 #if N_WORD_BITS == 64
2088 || (widetag_of(start_addr[1]) == SINGLE_FLOAT_WIDETAG)
2090 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2096 pointer, start_addr, *start_addr));
2099 case INSTANCE_POINTER_LOWTAG:
2100 if ((unsigned)pointer !=
2101 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2105 pointer, start_addr, *start_addr));
2108 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2112 pointer, start_addr, *start_addr));
2116 case OTHER_POINTER_LOWTAG:
2117 if ((unsigned)pointer !=
2118 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2122 pointer, start_addr, *start_addr));
2125 /* Is it plausible? Not a cons. XXX should check the headers. */
2126 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2130 pointer, start_addr, *start_addr));
2133 switch (widetag_of(start_addr[0])) {
2134 case UNBOUND_MARKER_WIDETAG:
2135 case CHARACTER_WIDETAG:
2136 #if N_WORD_BITS == 64
2137 case SINGLE_FLOAT_WIDETAG:
2142 pointer, start_addr, *start_addr));
2145 /* only pointed to by function pointers? */
2146 case CLOSURE_HEADER_WIDETAG:
2147 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2151 pointer, start_addr, *start_addr));
2154 case INSTANCE_HEADER_WIDETAG:
2158 pointer, start_addr, *start_addr));
2161 /* the valid other immediate pointer objects */
2162 case SIMPLE_VECTOR_WIDETAG:
2164 case COMPLEX_WIDETAG:
2165 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2166 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2168 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2169 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2171 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2172 case COMPLEX_LONG_FLOAT_WIDETAG:
2174 case SIMPLE_ARRAY_WIDETAG:
2175 case COMPLEX_BASE_STRING_WIDETAG:
2176 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
2177 case COMPLEX_CHARACTER_STRING_WIDETAG:
2179 case COMPLEX_VECTOR_NIL_WIDETAG:
2180 case COMPLEX_BIT_VECTOR_WIDETAG:
2181 case COMPLEX_VECTOR_WIDETAG:
2182 case COMPLEX_ARRAY_WIDETAG:
2183 case VALUE_CELL_HEADER_WIDETAG:
2184 case SYMBOL_HEADER_WIDETAG:
2186 case CODE_HEADER_WIDETAG:
2187 case BIGNUM_WIDETAG:
2188 #if N_WORD_BITS != 64
2189 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 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2197 case SIMPLE_CHARACTER_STRING_WIDETAG:
2199 case SIMPLE_BIT_VECTOR_WIDETAG:
2200 case SIMPLE_ARRAY_NIL_WIDETAG:
2201 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2202 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2203 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2204 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2205 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2206 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2207 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2208 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2210 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2211 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2212 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2213 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2215 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2216 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2218 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2219 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2221 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2222 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2224 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2225 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2227 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2228 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2230 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2231 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2233 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2234 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2236 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2237 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2239 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2240 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2241 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2242 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2244 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2245 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2247 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2248 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2250 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2251 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2254 case WEAK_POINTER_WIDETAG:
2261 pointer, start_addr, *start_addr));
2269 pointer, start_addr, *start_addr));
2277 /* Adjust large bignum and vector objects. This will adjust the
2278 * allocated region if the size has shrunk, and move unboxed objects
2279 * into unboxed pages. The pages are not promoted here, and the
2280 * promoted region is not added to the new_regions; this is really
2281 * only designed to be called from preserve_pointer(). Shouldn't fail
2282 * if this is missed, just may delay the moving of objects to unboxed
2283 * pages, and the freeing of pages. */
2285 maybe_adjust_large_object(lispobj *where)
2290 long remaining_bytes;
2293 long old_bytes_used;
2297 /* Check whether it's a vector or bignum object. */
2298 switch (widetag_of(where[0])) {
2299 case SIMPLE_VECTOR_WIDETAG:
2300 boxed = BOXED_PAGE_FLAG;
2302 case BIGNUM_WIDETAG:
2303 case SIMPLE_BASE_STRING_WIDETAG:
2304 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2305 case SIMPLE_CHARACTER_STRING_WIDETAG:
2307 case SIMPLE_BIT_VECTOR_WIDETAG:
2308 case SIMPLE_ARRAY_NIL_WIDETAG:
2309 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2310 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2311 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2312 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2313 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2314 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2315 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2316 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2318 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2319 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2320 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2321 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2323 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2324 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2326 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2327 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2329 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2330 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2332 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2333 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2335 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2336 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2338 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2339 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2341 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2342 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2344 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2345 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2347 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2348 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2349 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2350 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2352 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2353 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2355 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2356 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2358 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2359 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2361 boxed = UNBOXED_PAGE_FLAG;
2367 /* Find its current size. */
2368 nwords = (sizetab[widetag_of(where[0])])(where);
2370 first_page = find_page_index((void *)where);
2371 gc_assert(first_page >= 0);
2373 /* Note: Any page write-protection must be removed, else a later
2374 * scavenge_newspace may incorrectly not scavenge these pages.
2375 * This would not be necessary if they are added to the new areas,
2376 * but lets do it for them all (they'll probably be written
2379 gc_assert(page_table[first_page].first_object_offset == 0);
2381 next_page = first_page;
2382 remaining_bytes = nwords*N_WORD_BYTES;
2383 while (remaining_bytes > PAGE_BYTES) {
2384 gc_assert(page_table[next_page].gen == from_space);
2385 gc_assert((page_table[next_page].allocated == BOXED_PAGE_FLAG)
2386 || (page_table[next_page].allocated == UNBOXED_PAGE_FLAG));
2387 gc_assert(page_table[next_page].large_object);
2388 gc_assert(page_table[next_page].first_object_offset ==
2389 -PAGE_BYTES*(next_page-first_page));
2390 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2392 page_table[next_page].allocated = boxed;
2394 /* Shouldn't be write-protected at this stage. Essential that the
2396 gc_assert(!page_table[next_page].write_protected);
2397 remaining_bytes -= PAGE_BYTES;
2401 /* Now only one page remains, but the object may have shrunk so
2402 * there may be more unused pages which will be freed. */
2404 /* Object may have shrunk but shouldn't have grown - check. */
2405 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2407 page_table[next_page].allocated = boxed;
2408 gc_assert(page_table[next_page].allocated ==
2409 page_table[first_page].allocated);
2411 /* Adjust the bytes_used. */
2412 old_bytes_used = page_table[next_page].bytes_used;
2413 page_table[next_page].bytes_used = remaining_bytes;
2415 bytes_freed = old_bytes_used - remaining_bytes;
2417 /* Free any remaining pages; needs care. */
2419 while ((old_bytes_used == PAGE_BYTES) &&
2420 (page_table[next_page].gen == from_space) &&
2421 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
2422 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
2423 page_table[next_page].large_object &&
2424 (page_table[next_page].first_object_offset ==
2425 -(next_page - first_page)*PAGE_BYTES)) {
2426 /* It checks out OK, free the page. We don't need to both zeroing
2427 * pages as this should have been done before shrinking the
2428 * object. These pages shouldn't be write protected as they
2429 * should be zero filled. */
2430 gc_assert(page_table[next_page].write_protected == 0);
2432 old_bytes_used = page_table[next_page].bytes_used;
2433 page_table[next_page].allocated = FREE_PAGE_FLAG;
2434 page_table[next_page].bytes_used = 0;
2435 bytes_freed += old_bytes_used;
2439 if ((bytes_freed > 0) && gencgc_verbose) {
2441 "/maybe_adjust_large_object() freed %d\n",
2445 generations[from_space].bytes_allocated -= bytes_freed;
2446 bytes_allocated -= bytes_freed;
2451 /* Take a possible pointer to a Lisp object and mark its page in the
2452 * page_table so that it will not be relocated during a GC.
2454 * This involves locating the page it points to, then backing up to
2455 * the start of its region, then marking all pages dont_move from there
2456 * up to the first page that's not full or has a different generation
2458 * It is assumed that all the page static flags have been cleared at
2459 * the start of a GC.
2461 * It is also assumed that the current gc_alloc() region has been
2462 * flushed and the tables updated. */
2464 preserve_pointer(void *addr)
2466 long addr_page_index = find_page_index(addr);
2469 unsigned region_allocation;
2471 /* quick check 1: Address is quite likely to have been invalid. */
2472 if ((addr_page_index == -1)
2473 || (page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2474 || (page_table[addr_page_index].bytes_used == 0)
2475 || (page_table[addr_page_index].gen != from_space)
2476 /* Skip if already marked dont_move. */
2477 || (page_table[addr_page_index].dont_move != 0))
2479 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2480 /* (Now that we know that addr_page_index is in range, it's
2481 * safe to index into page_table[] with it.) */
2482 region_allocation = page_table[addr_page_index].allocated;
2484 /* quick check 2: Check the offset within the page.
2487 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2490 /* Filter out anything which can't be a pointer to a Lisp object
2491 * (or, as a special case which also requires dont_move, a return
2492 * address referring to something in a CodeObject). This is
2493 * expensive but important, since it vastly reduces the
2494 * probability that random garbage will be bogusly interpreted as
2495 * a pointer which prevents a page from moving. */
2496 if (!(possibly_valid_dynamic_space_pointer(addr)))
2499 /* Find the beginning of the region. Note that there may be
2500 * objects in the region preceding the one that we were passed a
2501 * pointer to: if this is the case, we will write-protect all the
2502 * previous objects' pages too. */
2505 /* I think this'd work just as well, but without the assertions.
2506 * -dan 2004.01.01 */
2508 find_page_index(page_address(addr_page_index)+
2509 page_table[addr_page_index].first_object_offset);
2511 first_page = addr_page_index;
2512 while (page_table[first_page].first_object_offset != 0) {
2514 /* Do some checks. */
2515 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2516 gc_assert(page_table[first_page].gen == from_space);
2517 gc_assert(page_table[first_page].allocated == region_allocation);
2521 /* Adjust any large objects before promotion as they won't be
2522 * copied after promotion. */
2523 if (page_table[first_page].large_object) {
2524 maybe_adjust_large_object(page_address(first_page));
2525 /* If a large object has shrunk then addr may now point to a
2526 * free area in which case it's ignored here. Note it gets
2527 * through the valid pointer test above because the tail looks
2529 if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2530 || (page_table[addr_page_index].bytes_used == 0)
2531 /* Check the offset within the page. */
2532 || (((unsigned)addr & (PAGE_BYTES - 1))
2533 > page_table[addr_page_index].bytes_used)) {
2535 "weird? ignore ptr 0x%x to freed area of large object\n",
2539 /* It may have moved to unboxed pages. */
2540 region_allocation = page_table[first_page].allocated;
2543 /* Now work forward until the end of this contiguous area is found,
2544 * marking all pages as dont_move. */
2545 for (i = first_page; ;i++) {
2546 gc_assert(page_table[i].allocated == region_allocation);
2548 /* Mark the page static. */
2549 page_table[i].dont_move = 1;
2551 /* Move the page to the new_space. XX I'd rather not do this
2552 * but the GC logic is not quite able to copy with the static
2553 * pages remaining in the from space. This also requires the
2554 * generation bytes_allocated counters be updated. */
2555 page_table[i].gen = new_space;
2556 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2557 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2559 /* It is essential that the pages are not write protected as
2560 * they may have pointers into the old-space which need
2561 * scavenging. They shouldn't be write protected at this
2563 gc_assert(!page_table[i].write_protected);
2565 /* Check whether this is the last page in this contiguous block.. */
2566 if ((page_table[i].bytes_used < PAGE_BYTES)
2567 /* ..or it is PAGE_BYTES and is the last in the block */
2568 || (page_table[i+1].allocated == FREE_PAGE_FLAG)
2569 || (page_table[i+1].bytes_used == 0) /* next page free */
2570 || (page_table[i+1].gen != from_space) /* diff. gen */
2571 || (page_table[i+1].first_object_offset == 0))
2575 /* Check that the page is now static. */
2576 gc_assert(page_table[addr_page_index].dont_move != 0);
2579 /* If the given page is not write-protected, then scan it for pointers
2580 * to younger generations or the top temp. generation, if no
2581 * suspicious pointers are found then the page is write-protected.
2583 * Care is taken to check for pointers to the current gc_alloc()
2584 * region if it is a younger generation or the temp. generation. This
2585 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2586 * the gc_alloc_generation does not need to be checked as this is only
2587 * called from scavenge_generation() when the gc_alloc generation is
2588 * younger, so it just checks if there is a pointer to the current
2591 * We return 1 if the page was write-protected, else 0. */
2593 update_page_write_prot(long page)
2595 int gen = page_table[page].gen;
2598 void **page_addr = (void **)page_address(page);
2599 long num_words = page_table[page].bytes_used / N_WORD_BYTES;
2601 /* Shouldn't be a free page. */
2602 gc_assert(page_table[page].allocated != FREE_PAGE_FLAG);
2603 gc_assert(page_table[page].bytes_used != 0);
2605 /* Skip if it's already write-protected, pinned, or unboxed */
2606 if (page_table[page].write_protected
2607 || page_table[page].dont_move
2608 || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
2611 /* Scan the page for pointers to younger generations or the
2612 * top temp. generation. */
2614 for (j = 0; j < num_words; j++) {
2615 void *ptr = *(page_addr+j);
2616 long index = find_page_index(ptr);
2618 /* Check that it's in the dynamic space */
2620 if (/* Does it point to a younger or the temp. generation? */
2621 ((page_table[index].allocated != FREE_PAGE_FLAG)
2622 && (page_table[index].bytes_used != 0)
2623 && ((page_table[index].gen < gen)
2624 || (page_table[index].gen == NUM_GENERATIONS)))
2626 /* Or does it point within a current gc_alloc() region? */
2627 || ((boxed_region.start_addr <= ptr)
2628 && (ptr <= boxed_region.free_pointer))
2629 || ((unboxed_region.start_addr <= ptr)
2630 && (ptr <= unboxed_region.free_pointer))) {
2637 /* Write-protect the page. */
2638 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2640 os_protect((void *)page_addr,
2642 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2644 /* Note the page as protected in the page tables. */
2645 page_table[page].write_protected = 1;
2651 /* Scavenge a generation.
2653 * This will not resolve all pointers when generation is the new
2654 * space, as new objects may be added which are not checked here - use
2655 * scavenge_newspace generation.
2657 * Write-protected pages should not have any pointers to the
2658 * from_space so do need scavenging; thus write-protected pages are
2659 * not always scavenged. There is some code to check that these pages
2660 * are not written; but to check fully the write-protected pages need
2661 * to be scavenged by disabling the code to skip them.
2663 * Under the current scheme when a generation is GCed the younger
2664 * generations will be empty. So, when a generation is being GCed it
2665 * is only necessary to scavenge the older generations for pointers
2666 * not the younger. So a page that does not have pointers to younger
2667 * generations does not need to be scavenged.
2669 * The write-protection can be used to note pages that don't have
2670 * pointers to younger pages. But pages can be written without having
2671 * pointers to younger generations. After the pages are scavenged here
2672 * they can be scanned for pointers to younger generations and if
2673 * there are none the page can be write-protected.
2675 * One complication is when the newspace is the top temp. generation.
2677 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2678 * that none were written, which they shouldn't be as they should have
2679 * no pointers to younger generations. This breaks down for weak
2680 * pointers as the objects contain a link to the next and are written
2681 * if a weak pointer is scavenged. Still it's a useful check. */
2683 scavenge_generation(int generation)
2690 /* Clear the write_protected_cleared flags on all pages. */
2691 for (i = 0; i < NUM_PAGES; i++)
2692 page_table[i].write_protected_cleared = 0;
2695 for (i = 0; i < last_free_page; i++) {
2696 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2697 && (page_table[i].bytes_used != 0)
2698 && (page_table[i].gen == generation)) {
2700 int write_protected=1;
2702 /* This should be the start of a region */
2703 gc_assert(page_table[i].first_object_offset == 0);
2705 /* Now work forward until the end of the region */
2706 for (last_page = i; ; last_page++) {
2708 write_protected && page_table[last_page].write_protected;
2709 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2710 /* Or it is PAGE_BYTES and is the last in the block */
2711 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2712 || (page_table[last_page+1].bytes_used == 0)
2713 || (page_table[last_page+1].gen != generation)
2714 || (page_table[last_page+1].first_object_offset == 0))
2717 if (!write_protected) {
2718 scavenge(page_address(i),
2719 (page_table[last_page].bytes_used +
2720 (last_page-i)*PAGE_BYTES)/N_WORD_BYTES);
2722 /* Now scan the pages and write protect those that
2723 * don't have pointers to younger generations. */
2724 if (enable_page_protection) {
2725 for (j = i; j <= last_page; j++) {
2726 num_wp += update_page_write_prot(j);
2733 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2735 "/write protected %d pages within generation %d\n",
2736 num_wp, generation));
2740 /* Check that none of the write_protected pages in this generation
2741 * have been written to. */
2742 for (i = 0; i < NUM_PAGES; i++) {
2743 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2744 && (page_table[i].bytes_used != 0)
2745 && (page_table[i].gen == generation)
2746 && (page_table[i].write_protected_cleared != 0)) {
2747 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2749 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2750 page_table[i].bytes_used,
2751 page_table[i].first_object_offset,
2752 page_table[i].dont_move));
2753 lose("write to protected page %d in scavenge_generation()", i);
2760 /* Scavenge a newspace generation. As it is scavenged new objects may
2761 * be allocated to it; these will also need to be scavenged. This
2762 * repeats until there are no more objects unscavenged in the
2763 * newspace generation.
2765 * To help improve the efficiency, areas written are recorded by
2766 * gc_alloc() and only these scavenged. Sometimes a little more will be
2767 * scavenged, but this causes no harm. An easy check is done that the
2768 * scavenged bytes equals the number allocated in the previous
2771 * Write-protected pages are not scanned except if they are marked
2772 * dont_move in which case they may have been promoted and still have
2773 * pointers to the from space.
2775 * Write-protected pages could potentially be written by alloc however
2776 * to avoid having to handle re-scavenging of write-protected pages
2777 * gc_alloc() does not write to write-protected pages.
2779 * New areas of objects allocated are recorded alternatively in the two
2780 * new_areas arrays below. */
2781 static struct new_area new_areas_1[NUM_NEW_AREAS];
2782 static struct new_area new_areas_2[NUM_NEW_AREAS];
2784 /* Do one full scan of the new space generation. This is not enough to
2785 * complete the job as new objects may be added to the generation in
2786 * the process which are not scavenged. */
2788 scavenge_newspace_generation_one_scan(int generation)
2793 "/starting one full scan of newspace generation %d\n",
2795 for (i = 0; i < last_free_page; i++) {
2796 /* Note that this skips over open regions when it encounters them. */
2797 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2798 && (page_table[i].bytes_used != 0)
2799 && (page_table[i].gen == generation)
2800 && ((page_table[i].write_protected == 0)
2801 /* (This may be redundant as write_protected is now
2802 * cleared before promotion.) */
2803 || (page_table[i].dont_move == 1))) {
2807 /* The scavenge will start at the first_object_offset of page i.
2809 * We need to find the full extent of this contiguous
2810 * block in case objects span pages.
2812 * Now work forward until the end of this contiguous area
2813 * is found. A small area is preferred as there is a
2814 * better chance of its pages being write-protected. */
2815 for (last_page = i; ;last_page++) {
2816 /* If all pages are write-protected and movable,
2817 * then no need to scavenge */
2818 all_wp=all_wp && page_table[last_page].write_protected &&
2819 !page_table[last_page].dont_move;
2821 /* Check whether this is the last page in this
2822 * contiguous block */
2823 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2824 /* Or it is PAGE_BYTES and is the last in the block */
2825 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2826 || (page_table[last_page+1].bytes_used == 0)
2827 || (page_table[last_page+1].gen != generation)
2828 || (page_table[last_page+1].first_object_offset == 0))
2832 /* Do a limited check for write-protected pages. */
2836 size = (page_table[last_page].bytes_used
2837 + (last_page-i)*PAGE_BYTES
2838 - page_table[i].first_object_offset)/N_WORD_BYTES;
2839 new_areas_ignore_page = last_page;
2841 scavenge(page_address(i) +
2842 page_table[i].first_object_offset,
2850 "/done with one full scan of newspace generation %d\n",
2854 /* Do a complete scavenge of the newspace generation. */
2856 scavenge_newspace_generation(int generation)
2860 /* the new_areas array currently being written to by gc_alloc() */
2861 struct new_area (*current_new_areas)[] = &new_areas_1;
2862 long current_new_areas_index;
2864 /* the new_areas created by the previous scavenge cycle */
2865 struct new_area (*previous_new_areas)[] = NULL;
2866 long previous_new_areas_index;
2868 /* Flush the current regions updating the tables. */
2869 gc_alloc_update_all_page_tables();
2871 /* Turn on the recording of new areas by gc_alloc(). */
2872 new_areas = current_new_areas;
2873 new_areas_index = 0;
2875 /* Don't need to record new areas that get scavenged anyway during
2876 * scavenge_newspace_generation_one_scan. */
2877 record_new_objects = 1;
2879 /* Start with a full scavenge. */
2880 scavenge_newspace_generation_one_scan(generation);
2882 /* Record all new areas now. */
2883 record_new_objects = 2;
2885 /* Flush the current regions updating the tables. */
2886 gc_alloc_update_all_page_tables();
2888 /* Grab new_areas_index. */
2889 current_new_areas_index = new_areas_index;
2892 "The first scan is finished; current_new_areas_index=%d.\n",
2893 current_new_areas_index));*/
2895 while (current_new_areas_index > 0) {
2896 /* Move the current to the previous new areas */
2897 previous_new_areas = current_new_areas;
2898 previous_new_areas_index = current_new_areas_index;
2900 /* Scavenge all the areas in previous new areas. Any new areas
2901 * allocated are saved in current_new_areas. */
2903 /* Allocate an array for current_new_areas; alternating between
2904 * new_areas_1 and 2 */
2905 if (previous_new_areas == &new_areas_1)
2906 current_new_areas = &new_areas_2;
2908 current_new_areas = &new_areas_1;
2910 /* Set up for gc_alloc(). */
2911 new_areas = current_new_areas;
2912 new_areas_index = 0;
2914 /* Check whether previous_new_areas had overflowed. */
2915 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2917 /* New areas of objects allocated have been lost so need to do a
2918 * full scan to be sure! If this becomes a problem try
2919 * increasing NUM_NEW_AREAS. */
2921 SHOW("new_areas overflow, doing full scavenge");
2923 /* Don't need to record new areas that get scavenge anyway
2924 * during scavenge_newspace_generation_one_scan. */
2925 record_new_objects = 1;
2927 scavenge_newspace_generation_one_scan(generation);
2929 /* Record all new areas now. */
2930 record_new_objects = 2;
2932 /* Flush the current regions updating the tables. */
2933 gc_alloc_update_all_page_tables();
2937 /* Work through previous_new_areas. */
2938 for (i = 0; i < previous_new_areas_index; i++) {
2939 long page = (*previous_new_areas)[i].page;
2940 long offset = (*previous_new_areas)[i].offset;
2941 long size = (*previous_new_areas)[i].size / N_WORD_BYTES;
2942 gc_assert((*previous_new_areas)[i].size % N_WORD_BYTES == 0);
2943 scavenge(page_address(page)+offset, size);
2946 /* Flush the current regions updating the tables. */
2947 gc_alloc_update_all_page_tables();
2950 current_new_areas_index = new_areas_index;
2953 "The re-scan has finished; current_new_areas_index=%d.\n",
2954 current_new_areas_index));*/
2957 /* Turn off recording of areas allocated by gc_alloc(). */
2958 record_new_objects = 0;
2961 /* Check that none of the write_protected pages in this generation
2962 * have been written to. */
2963 for (i = 0; i < NUM_PAGES; i++) {
2964 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2965 && (page_table[i].bytes_used != 0)
2966 && (page_table[i].gen == generation)
2967 && (page_table[i].write_protected_cleared != 0)
2968 && (page_table[i].dont_move == 0)) {
2969 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2970 i, generation, page_table[i].dont_move);
2976 /* Un-write-protect all the pages in from_space. This is done at the
2977 * start of a GC else there may be many page faults while scavenging
2978 * the newspace (I've seen drive the system time to 99%). These pages
2979 * would need to be unprotected anyway before unmapping in
2980 * free_oldspace; not sure what effect this has on paging.. */
2982 unprotect_oldspace(void)
2986 for (i = 0; i < last_free_page; i++) {
2987 if ((page_table[i].allocated != FREE_PAGE_FLAG)
2988 && (page_table[i].bytes_used != 0)
2989 && (page_table[i].gen == from_space)) {
2992 page_start = (void *)page_address(i);
2994 /* Remove any write-protection. We should be able to rely
2995 * on the write-protect flag to avoid redundant calls. */
2996 if (page_table[i].write_protected) {
2997 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2998 page_table[i].write_protected = 0;
3004 /* Work through all the pages and free any in from_space. This
3005 * assumes that all objects have been copied or promoted to an older
3006 * generation. Bytes_allocated and the generation bytes_allocated
3007 * counter are updated. The number of bytes freed is returned. */
3011 long bytes_freed = 0;
3012 long first_page, last_page;
3017 /* Find a first page for the next region of pages. */
3018 while ((first_page < last_free_page)
3019 && ((page_table[first_page].allocated == FREE_PAGE_FLAG)
3020 || (page_table[first_page].bytes_used == 0)
3021 || (page_table[first_page].gen != from_space)))
3024 if (first_page >= last_free_page)
3027 /* Find the last page of this region. */
3028 last_page = first_page;
3031 /* Free the page. */
3032 bytes_freed += page_table[last_page].bytes_used;
3033 generations[page_table[last_page].gen].bytes_allocated -=
3034 page_table[last_page].bytes_used;
3035 page_table[last_page].allocated = FREE_PAGE_FLAG;
3036 page_table[last_page].bytes_used = 0;
3038 /* Remove any write-protection. We should be able to rely
3039 * on the write-protect flag to avoid redundant calls. */
3041 void *page_start = (void *)page_address(last_page);
3043 if (page_table[last_page].write_protected) {
3044 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3045 page_table[last_page].write_protected = 0;
3050 while ((last_page < last_free_page)
3051 && (page_table[last_page].allocated != FREE_PAGE_FLAG)
3052 && (page_table[last_page].bytes_used != 0)
3053 && (page_table[last_page].gen == from_space));
3055 /* Zero pages from first_page to (last_page-1).
3057 * FIXME: Why not use os_zero(..) function instead of
3058 * hand-coding this again? (Check other gencgc_unmap_zero
3060 if (gencgc_unmap_zero) {
3061 void *page_start, *addr;
3063 page_start = (void *)page_address(first_page);
3065 os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
3066 addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
3067 if (addr == NULL || addr != page_start) {
3068 lose("free_oldspace: page moved, 0x%08x ==> 0x%08x",page_start,
3074 page_start = (long *)page_address(first_page);
3075 memset(page_start, 0,PAGE_BYTES*(last_page-first_page));
3078 first_page = last_page;
3080 } while (first_page < last_free_page);
3082 bytes_allocated -= bytes_freed;
3087 /* Print some information about a pointer at the given address. */
3089 print_ptr(lispobj *addr)
3091 /* If addr is in the dynamic space then out the page information. */
3092 long pi1 = find_page_index((void*)addr);
3095 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3096 (unsigned long) addr,
3098 page_table[pi1].allocated,
3099 page_table[pi1].gen,
3100 page_table[pi1].bytes_used,
3101 page_table[pi1].first_object_offset,
3102 page_table[pi1].dont_move);
3103 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3116 extern long undefined_tramp;
3119 verify_space(lispobj *start, size_t words)
3121 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3122 int is_in_readonly_space =
3123 (READ_ONLY_SPACE_START <= (unsigned)start &&
3124 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3128 lispobj thing = *(lispobj*)start;
3130 if (is_lisp_pointer(thing)) {
3131 long page_index = find_page_index((void*)thing);
3132 long to_readonly_space =
3133 (READ_ONLY_SPACE_START <= thing &&
3134 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3135 long to_static_space =
3136 (STATIC_SPACE_START <= thing &&
3137 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3139 /* Does it point to the dynamic space? */
3140 if (page_index != -1) {
3141 /* If it's within the dynamic space it should point to a used
3142 * page. XX Could check the offset too. */
3143 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
3144 && (page_table[page_index].bytes_used == 0))
3145 lose ("Ptr %x @ %x sees free page.", thing, start);
3146 /* Check that it doesn't point to a forwarding pointer! */
3147 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3148 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3150 /* Check that its not in the RO space as it would then be a
3151 * pointer from the RO to the dynamic space. */
3152 if (is_in_readonly_space) {
3153 lose("ptr to dynamic space %x from RO space %x",
3156 /* Does it point to a plausible object? This check slows
3157 * it down a lot (so it's commented out).
3159 * "a lot" is serious: it ate 50 minutes cpu time on
3160 * my duron 950 before I came back from lunch and
3163 * FIXME: Add a variable to enable this
3166 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3167 lose("ptr %x to invalid object %x", thing, start);
3171 /* Verify that it points to another valid space. */
3172 if (!to_readonly_space && !to_static_space
3173 && (thing != (unsigned)&undefined_tramp)) {
3174 lose("Ptr %x @ %x sees junk.", thing, start);
3178 if (!(fixnump(thing))) {
3180 switch(widetag_of(*start)) {
3183 case SIMPLE_VECTOR_WIDETAG:
3185 case COMPLEX_WIDETAG:
3186 case SIMPLE_ARRAY_WIDETAG:
3187 case COMPLEX_BASE_STRING_WIDETAG:
3188 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
3189 case COMPLEX_CHARACTER_STRING_WIDETAG:
3191 case COMPLEX_VECTOR_NIL_WIDETAG:
3192 case COMPLEX_BIT_VECTOR_WIDETAG:
3193 case COMPLEX_VECTOR_WIDETAG:
3194 case COMPLEX_ARRAY_WIDETAG:
3195 case CLOSURE_HEADER_WIDETAG:
3196 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3197 case VALUE_CELL_HEADER_WIDETAG:
3198 case SYMBOL_HEADER_WIDETAG:
3199 case CHARACTER_WIDETAG:
3200 #if N_WORD_BITS == 64
3201 case SINGLE_FLOAT_WIDETAG:
3203 case UNBOUND_MARKER_WIDETAG:
3204 case INSTANCE_HEADER_WIDETAG:
3209 case CODE_HEADER_WIDETAG:
3211 lispobj object = *start;
3213 long nheader_words, ncode_words, nwords;
3215 struct simple_fun *fheaderp;
3217 code = (struct code *) start;
3219 /* Check that it's not in the dynamic space.
3220 * FIXME: Isn't is supposed to be OK for code
3221 * objects to be in the dynamic space these days? */
3222 if (is_in_dynamic_space
3223 /* It's ok if it's byte compiled code. The trace
3224 * table offset will be a fixnum if it's x86
3225 * compiled code - check.
3227 * FIXME: #^#@@! lack of abstraction here..
3228 * This line can probably go away now that
3229 * there's no byte compiler, but I've got
3230 * too much to worry about right now to try
3231 * to make sure. -- WHN 2001-10-06 */
3232 && fixnump(code->trace_table_offset)
3233 /* Only when enabled */
3234 && verify_dynamic_code_check) {
3236 "/code object at %x in the dynamic space\n",
3240 ncode_words = fixnum_value(code->code_size);
3241 nheader_words = HeaderValue(object);
3242 nwords = ncode_words + nheader_words;
3243 nwords = CEILING(nwords, 2);
3244 /* Scavenge the boxed section of the code data block */
3245 verify_space(start + 1, nheader_words - 1);
3247 /* Scavenge the boxed section of each function
3248 * object in the code data block. */
3249 fheaderl = code->entry_points;
3250 while (fheaderl != NIL) {
3252 (struct simple_fun *) native_pointer(fheaderl);
3253 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3254 verify_space(&fheaderp->name, 1);
3255 verify_space(&fheaderp->arglist, 1);
3256 verify_space(&fheaderp->type, 1);
3257 fheaderl = fheaderp->next;
3263 /* unboxed objects */
3264 case BIGNUM_WIDETAG:
3265 #if N_WORD_BITS != 64
3266 case SINGLE_FLOAT_WIDETAG:
3268 case DOUBLE_FLOAT_WIDETAG:
3269 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3270 case LONG_FLOAT_WIDETAG:
3272 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3273 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3275 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3276 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3278 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3279 case COMPLEX_LONG_FLOAT_WIDETAG:
3281 case SIMPLE_BASE_STRING_WIDETAG:
3282 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
3283 case SIMPLE_CHARACTER_STRING_WIDETAG:
3285 case SIMPLE_BIT_VECTOR_WIDETAG:
3286 case SIMPLE_ARRAY_NIL_WIDETAG:
3287 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3288 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3289 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3290 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3291 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3292 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3293 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
3294 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3296 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3297 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3298 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
3299 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
3301 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
3302 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
3304 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
3305 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
3307 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3308 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3310 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3311 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3313 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3314 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3316 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3317 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3319 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
3320 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
3322 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
3323 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
3325 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3326 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3327 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3328 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3330 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3331 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3333 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3334 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3336 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3337 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3340 case WEAK_POINTER_WIDETAG:
3341 count = (sizetab[widetag_of(*start)])(start);
3357 /* FIXME: It would be nice to make names consistent so that
3358 * foo_size meant size *in* *bytes* instead of size in some
3359 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3360 * Some counts of lispobjs are called foo_count; it might be good
3361 * to grep for all foo_size and rename the appropriate ones to
3363 long read_only_space_size =
3364 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3365 - (lispobj*)READ_ONLY_SPACE_START;
3366 long static_space_size =
3367 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3368 - (lispobj*)STATIC_SPACE_START;
3370 for_each_thread(th) {
3371 long binding_stack_size =
3372 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3373 - (lispobj*)th->binding_stack_start;
3374 verify_space(th->binding_stack_start, binding_stack_size);
3376 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3377 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3381 verify_generation(int generation)
3385 for (i = 0; i < last_free_page; i++) {
3386 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3387 && (page_table[i].bytes_used != 0)
3388 && (page_table[i].gen == generation)) {
3390 int region_allocation = page_table[i].allocated;
3392 /* This should be the start of a contiguous block */
3393 gc_assert(page_table[i].first_object_offset == 0);
3395 /* Need to find the full extent of this contiguous block in case
3396 objects span pages. */
3398 /* Now work forward until the end of this contiguous area is
3400 for (last_page = i; ;last_page++)
3401 /* Check whether this is the last page in this contiguous
3403 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3404 /* Or it is PAGE_BYTES and is the last in the block */
3405 || (page_table[last_page+1].allocated != region_allocation)
3406 || (page_table[last_page+1].bytes_used == 0)
3407 || (page_table[last_page+1].gen != generation)
3408 || (page_table[last_page+1].first_object_offset == 0))
3411 verify_space(page_address(i), (page_table[last_page].bytes_used
3412 + (last_page-i)*PAGE_BYTES)/N_WORD_BYTES);
3418 /* Check that all the free space is zero filled. */
3420 verify_zero_fill(void)
3424 for (page = 0; page < last_free_page; page++) {
3425 if (page_table[page].allocated == FREE_PAGE_FLAG) {
3426 /* The whole page should be zero filled. */
3427 long *start_addr = (long *)page_address(page);
3430 for (i = 0; i < size; i++) {
3431 if (start_addr[i] != 0) {
3432 lose("free page not zero at %x", start_addr + i);
3436 long free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3437 if (free_bytes > 0) {
3438 long *start_addr = (long *)((unsigned)page_address(page)
3439 + page_table[page].bytes_used);
3440 long size = free_bytes / N_WORD_BYTES;
3442 for (i = 0; i < size; i++) {
3443 if (start_addr[i] != 0) {
3444 lose("free region not zero at %x", start_addr + i);
3452 /* External entry point for verify_zero_fill */
3454 gencgc_verify_zero_fill(void)
3456 /* Flush the alloc regions updating the tables. */
3457 gc_alloc_update_all_page_tables();
3458 SHOW("verifying zero fill");
3463 verify_dynamic_space(void)
3467 for (i = 0; i < NUM_GENERATIONS; i++)
3468 verify_generation(i);
3470 if (gencgc_enable_verify_zero_fill)
3474 /* Write-protect all the dynamic boxed pages in the given generation. */
3476 write_protect_generation_pages(int generation)
3480 gc_assert(generation < NUM_GENERATIONS);
3482 for (i = 0; i < last_free_page; i++)
3483 if ((page_table[i].allocated == BOXED_PAGE_FLAG)
3484 && (page_table[i].bytes_used != 0)
3485 && !page_table[i].dont_move
3486 && (page_table[i].gen == generation)) {
3489 page_start = (void *)page_address(i);
3491 os_protect(page_start,
3493 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3495 /* Note the page as protected in the page tables. */
3496 page_table[i].write_protected = 1;
3499 if (gencgc_verbose > 1) {
3501 "/write protected %d of %d pages in generation %d\n",
3502 count_write_protect_generation_pages(generation),
3503 count_generation_pages(generation),
3508 /* Garbage collect a generation. If raise is 0 then the remains of the
3509 * generation are not raised to the next generation. */
3511 garbage_collect_generation(int generation, int raise)
3513 unsigned long bytes_freed;
3515 unsigned long static_space_size;
3517 gc_assert(generation <= (NUM_GENERATIONS-1));
3519 /* The oldest generation can't be raised. */
3520 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3522 /* Initialize the weak pointer list. */
3523 weak_pointers = NULL;
3525 /* When a generation is not being raised it is transported to a
3526 * temporary generation (NUM_GENERATIONS), and lowered when
3527 * done. Set up this new generation. There should be no pages
3528 * allocated to it yet. */
3530 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3533 /* Set the global src and dest. generations */
3534 from_space = generation;
3536 new_space = generation+1;
3538 new_space = NUM_GENERATIONS;
3540 /* Change to a new space for allocation, resetting the alloc_start_page */
3541 gc_alloc_generation = new_space;
3542 generations[new_space].alloc_start_page = 0;
3543 generations[new_space].alloc_unboxed_start_page = 0;
3544 generations[new_space].alloc_large_start_page = 0;
3545 generations[new_space].alloc_large_unboxed_start_page = 0;
3547 /* Before any pointers are preserved, the dont_move flags on the
3548 * pages need to be cleared. */
3549 for (i = 0; i < last_free_page; i++)
3550 if(page_table[i].gen==from_space)
3551 page_table[i].dont_move = 0;
3553 /* Un-write-protect the old-space pages. This is essential for the
3554 * promoted pages as they may contain pointers into the old-space
3555 * which need to be scavenged. It also helps avoid unnecessary page
3556 * faults as forwarding pointers are written into them. They need to
3557 * be un-protected anyway before unmapping later. */
3558 unprotect_oldspace();
3560 /* Scavenge the stacks' conservative roots. */
3562 /* there are potentially two stacks for each thread: the main
3563 * stack, which may contain Lisp pointers, and the alternate stack.
3564 * We don't ever run Lisp code on the altstack, but it may
3565 * host a sigcontext with lisp objects in it */
3567 /* what we need to do: (1) find the stack pointer for the main
3568 * stack; scavenge it (2) find the interrupt context on the
3569 * alternate stack that might contain lisp values, and scavenge
3572 /* we assume that none of the preceding applies to the thread that
3573 * initiates GC. If you ever call GC from inside an altstack
3574 * handler, you will lose. */
3575 for_each_thread(th) {
3577 void **esp=(void **)-1;
3578 #ifdef LISP_FEATURE_SB_THREAD
3580 if(th==arch_os_get_current_thread()) {
3581 /* Somebody is going to burn in hell for this, but casting
3582 * it in two steps shuts gcc up about strict aliasing. */
3583 esp = (void **)((void *)&raise);
3586 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3587 for(i=free-1;i>=0;i--) {
3588 os_context_t *c=th->interrupt_contexts[i];
3589 esp1 = (void **) *os_context_register_addr(c,reg_SP);
3590 if (esp1>=(void **)th->control_stack_start &&
3591 esp1<(void **)th->control_stack_end) {
3592 if(esp1<esp) esp=esp1;
3593 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3594 preserve_pointer(*ptr);
3600 esp = (void **)((void *)&raise);
3602 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3603 preserve_pointer(*ptr);
3608 if (gencgc_verbose > 1) {
3609 long num_dont_move_pages = count_dont_move_pages();
3611 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3612 num_dont_move_pages,
3613 num_dont_move_pages * PAGE_BYTES);
3617 /* Scavenge all the rest of the roots. */
3619 /* Scavenge the Lisp functions of the interrupt handlers, taking
3620 * care to avoid SIG_DFL and SIG_IGN. */
3621 for_each_thread(th) {
3622 struct interrupt_data *data=th->interrupt_data;
3623 for (i = 0; i < NSIG; i++) {
3624 union interrupt_handler handler = data->interrupt_handlers[i];
3625 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3626 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3627 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3631 /* Scavenge the binding stacks. */
3634 for_each_thread(th) {
3635 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3636 th->binding_stack_start;
3637 scavenge((lispobj *) th->binding_stack_start,len);
3638 #ifdef LISP_FEATURE_SB_THREAD
3639 /* do the tls as well */
3640 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3641 (sizeof (struct thread))/(sizeof (lispobj));
3642 scavenge((lispobj *) (th+1),len);
3647 /* The original CMU CL code had scavenge-read-only-space code
3648 * controlled by the Lisp-level variable
3649 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3650 * wasn't documented under what circumstances it was useful or
3651 * safe to turn it on, so it's been turned off in SBCL. If you
3652 * want/need this functionality, and can test and document it,
3653 * please submit a patch. */
3655 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3656 unsigned long read_only_space_size =
3657 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3658 (lispobj*)READ_ONLY_SPACE_START;
3660 "/scavenge read only space: %d bytes\n",
3661 read_only_space_size * sizeof(lispobj)));
3662 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3666 /* Scavenge static space. */
3668 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3669 (lispobj *)STATIC_SPACE_START;
3670 if (gencgc_verbose > 1) {
3672 "/scavenge static space: %d bytes\n",
3673 static_space_size * sizeof(lispobj)));
3675 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3677 /* All generations but the generation being GCed need to be
3678 * scavenged. The new_space generation needs special handling as
3679 * objects may be moved in - it is handled separately below. */
3680 for (i = 0; i < NUM_GENERATIONS; i++) {
3681 if ((i != generation) && (i != new_space)) {
3682 scavenge_generation(i);
3686 /* Finally scavenge the new_space generation. Keep going until no
3687 * more objects are moved into the new generation */
3688 scavenge_newspace_generation(new_space);
3690 /* FIXME: I tried reenabling this check when debugging unrelated
3691 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3692 * Since the current GC code seems to work well, I'm guessing that
3693 * this debugging code is just stale, but I haven't tried to
3694 * figure it out. It should be figured out and then either made to
3695 * work or just deleted. */
3696 #define RESCAN_CHECK 0
3698 /* As a check re-scavenge the newspace once; no new objects should
3701 long old_bytes_allocated = bytes_allocated;
3702 long bytes_allocated;
3704 /* Start with a full scavenge. */
3705 scavenge_newspace_generation_one_scan(new_space);
3707 /* Flush the current regions, updating the tables. */
3708 gc_alloc_update_all_page_tables();
3710 bytes_allocated = bytes_allocated - old_bytes_allocated;
3712 if (bytes_allocated != 0) {
3713 lose("Rescan of new_space allocated %d more bytes.",
3719 scan_weak_pointers();
3721 /* Flush the current regions, updating the tables. */
3722 gc_alloc_update_all_page_tables();
3724 /* Free the pages in oldspace, but not those marked dont_move. */
3725 bytes_freed = free_oldspace();
3727 /* If the GC is not raising the age then lower the generation back
3728 * to its normal generation number */
3730 for (i = 0; i < last_free_page; i++)
3731 if ((page_table[i].bytes_used != 0)
3732 && (page_table[i].gen == NUM_GENERATIONS))
3733 page_table[i].gen = generation;
3734 gc_assert(generations[generation].bytes_allocated == 0);
3735 generations[generation].bytes_allocated =
3736 generations[NUM_GENERATIONS].bytes_allocated;
3737 generations[NUM_GENERATIONS].bytes_allocated = 0;
3740 /* Reset the alloc_start_page for generation. */
3741 generations[generation].alloc_start_page = 0;
3742 generations[generation].alloc_unboxed_start_page = 0;
3743 generations[generation].alloc_large_start_page = 0;
3744 generations[generation].alloc_large_unboxed_start_page = 0;
3746 if (generation >= verify_gens) {
3750 verify_dynamic_space();
3753 /* Set the new gc trigger for the GCed generation. */
3754 generations[generation].gc_trigger =
3755 generations[generation].bytes_allocated
3756 + generations[generation].bytes_consed_between_gc;
3759 generations[generation].num_gc = 0;
3761 ++generations[generation].num_gc;
3764 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3766 update_x86_dynamic_space_free_pointer(void)
3768 long last_page = -1;
3771 for (i = 0; i < last_free_page; i++)
3772 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3773 && (page_table[i].bytes_used != 0))
3776 last_free_page = last_page+1;
3778 SetSymbolValue(ALLOCATION_POINTER,
3779 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3780 return 0; /* dummy value: return something ... */
3783 /* GC all generations newer than last_gen, raising the objects in each
3784 * to the next older generation - we finish when all generations below
3785 * last_gen are empty. Then if last_gen is due for a GC, or if
3786 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3787 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3789 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3790 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3793 collect_garbage(unsigned last_gen)
3800 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3802 if (last_gen > NUM_GENERATIONS) {
3804 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3809 /* Flush the alloc regions updating the tables. */
3810 gc_alloc_update_all_page_tables();
3812 /* Verify the new objects created by Lisp code. */
3813 if (pre_verify_gen_0) {
3814 FSHOW((stderr, "pre-checking generation 0\n"));
3815 verify_generation(0);
3818 if (gencgc_verbose > 1)
3819 print_generation_stats(0);
3822 /* Collect the generation. */
3824 if (gen >= gencgc_oldest_gen_to_gc) {
3825 /* Never raise the oldest generation. */
3830 || (generations[gen].num_gc >= generations[gen].trigger_age);
3833 if (gencgc_verbose > 1) {
3835 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3838 generations[gen].bytes_allocated,
3839 generations[gen].gc_trigger,
3840 generations[gen].num_gc));
3843 /* If an older generation is being filled, then update its
3846 generations[gen+1].cum_sum_bytes_allocated +=
3847 generations[gen+1].bytes_allocated;
3850 garbage_collect_generation(gen, raise);
3852 /* Reset the memory age cum_sum. */
3853 generations[gen].cum_sum_bytes_allocated = 0;
3855 if (gencgc_verbose > 1) {
3856 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3857 print_generation_stats(0);
3861 } while ((gen <= gencgc_oldest_gen_to_gc)
3862 && ((gen < last_gen)
3863 || ((gen <= gencgc_oldest_gen_to_gc)
3865 && (generations[gen].bytes_allocated
3866 > generations[gen].gc_trigger)
3867 && (gen_av_mem_age(gen)
3868 > generations[gen].min_av_mem_age))));
3870 /* Now if gen-1 was raised all generations before gen are empty.
3871 * If it wasn't raised then all generations before gen-1 are empty.
3873 * Now objects within this gen's pages cannot point to younger
3874 * generations unless they are written to. This can be exploited
3875 * by write-protecting the pages of gen; then when younger
3876 * generations are GCed only the pages which have been written
3881 gen_to_wp = gen - 1;
3883 /* There's not much point in WPing pages in generation 0 as it is
3884 * never scavenged (except promoted pages). */
3885 if ((gen_to_wp > 0) && enable_page_protection) {
3886 /* Check that they are all empty. */
3887 for (i = 0; i < gen_to_wp; i++) {
3888 if (generations[i].bytes_allocated)
3889 lose("trying to write-protect gen. %d when gen. %d nonempty",
3892 write_protect_generation_pages(gen_to_wp);
3895 /* Set gc_alloc() back to generation 0. The current regions should
3896 * be flushed after the above GCs. */
3897 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3898 gc_alloc_generation = 0;
3900 update_x86_dynamic_space_free_pointer();
3901 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3903 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3905 SHOW("returning from collect_garbage");
3908 /* This is called by Lisp PURIFY when it is finished. All live objects
3909 * will have been moved to the RO and Static heaps. The dynamic space
3910 * will need a full re-initialization. We don't bother having Lisp
3911 * PURIFY flush the current gc_alloc() region, as the page_tables are
3912 * re-initialized, and every page is zeroed to be sure. */
3918 if (gencgc_verbose > 1)
3919 SHOW("entering gc_free_heap");
3921 for (page = 0; page < NUM_PAGES; page++) {
3922 /* Skip free pages which should already be zero filled. */
3923 if (page_table[page].allocated != FREE_PAGE_FLAG) {
3924 void *page_start, *addr;
3926 /* Mark the page free. The other slots are assumed invalid
3927 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3928 * should not be write-protected -- except that the
3929 * generation is used for the current region but it sets
3931 page_table[page].allocated = FREE_PAGE_FLAG;
3932 page_table[page].bytes_used = 0;
3934 /* Zero the page. */
3935 page_start = (void *)page_address(page);
3937 /* First, remove any write-protection. */
3938 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3939 page_table[page].write_protected = 0;
3941 os_invalidate(page_start,PAGE_BYTES);
3942 addr = os_validate(page_start,PAGE_BYTES);
3943 if (addr == NULL || addr != page_start) {
3944 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3948 } else if (gencgc_zero_check_during_free_heap) {
3949 /* Double-check that the page is zero filled. */
3950 long *page_start, i;
3951 gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
3952 gc_assert(page_table[page].bytes_used == 0);
3953 page_start = (long *)page_address(page);
3954 for (i=0; i<1024; i++) {
3955 if (page_start[i] != 0) {
3956 lose("free region not zero at %x", page_start + i);
3962 bytes_allocated = 0;
3964 /* Initialize the generations. */
3965 for (page = 0; page < NUM_GENERATIONS; page++) {
3966 generations[page].alloc_start_page = 0;
3967 generations[page].alloc_unboxed_start_page = 0;
3968 generations[page].alloc_large_start_page = 0;
3969 generations[page].alloc_large_unboxed_start_page = 0;
3970 generations[page].bytes_allocated = 0;
3971 generations[page].gc_trigger = 2000000;
3972 generations[page].num_gc = 0;
3973 generations[page].cum_sum_bytes_allocated = 0;
3976 if (gencgc_verbose > 1)
3977 print_generation_stats(0);
3979 /* Initialize gc_alloc(). */
3980 gc_alloc_generation = 0;
3982 gc_set_region_empty(&boxed_region);
3983 gc_set_region_empty(&unboxed_region);
3986 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3988 if (verify_after_free_heap) {
3989 /* Check whether purify has left any bad pointers. */
3991 SHOW("checking after free_heap\n");
4002 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
4003 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
4004 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
4006 heap_base = (void*)DYNAMIC_SPACE_START;
4008 /* Initialize each page structure. */
4009 for (i = 0; i < NUM_PAGES; i++) {
4010 /* Initialize all pages as free. */
4011 page_table[i].allocated = FREE_PAGE_FLAG;
4012 page_table[i].bytes_used = 0;
4014 /* Pages are not write-protected at startup. */
4015 page_table[i].write_protected = 0;
4018 bytes_allocated = 0;
4020 /* Initialize the generations.
4022 * FIXME: very similar to code in gc_free_heap(), should be shared */
4023 for (i = 0; i < NUM_GENERATIONS; i++) {
4024 generations[i].alloc_start_page = 0;
4025 generations[i].alloc_unboxed_start_page = 0;
4026 generations[i].alloc_large_start_page = 0;
4027 generations[i].alloc_large_unboxed_start_page = 0;
4028 generations[i].bytes_allocated = 0;
4029 generations[i].gc_trigger = 2000000;
4030 generations[i].num_gc = 0;
4031 generations[i].cum_sum_bytes_allocated = 0;
4032 /* the tune-able parameters */
4033 generations[i].bytes_consed_between_gc = 2000000;
4034 generations[i].trigger_age = 1;
4035 generations[i].min_av_mem_age = 0.75;
4038 /* Initialize gc_alloc. */
4039 gc_alloc_generation = 0;
4040 gc_set_region_empty(&boxed_region);
4041 gc_set_region_empty(&unboxed_region);
4047 /* Pick up the dynamic space from after a core load.
4049 * The ALLOCATION_POINTER points to the end of the dynamic space.
4053 gencgc_pickup_dynamic(void)
4056 long alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
4057 lispobj *prev=(lispobj *)page_address(page);
4060 lispobj *first,*ptr= (lispobj *)page_address(page);
4061 page_table[page].allocated = BOXED_PAGE_FLAG;
4062 page_table[page].gen = 0;
4063 page_table[page].bytes_used = PAGE_BYTES;
4064 page_table[page].large_object = 0;
4066 first=gc_search_space(prev,(ptr+2)-prev,ptr);
4067 if(ptr == first) prev=ptr;
4068 page_table[page].first_object_offset =
4069 (void *)prev - page_address(page);
4071 } while ((long)page_address(page) < alloc_ptr);
4073 generations[0].bytes_allocated = PAGE_BYTES*page;
4074 bytes_allocated = PAGE_BYTES*page;
4080 gc_initialize_pointers(void)
4082 gencgc_pickup_dynamic();
4088 /* alloc(..) is the external interface for memory allocation. It
4089 * allocates to generation 0. It is not called from within the garbage
4090 * collector as it is only external uses that need the check for heap
4091 * size (GC trigger) and to disable the interrupts (interrupts are
4092 * always disabled during a GC).
4094 * The vops that call alloc(..) assume that the returned space is zero-filled.
4095 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4097 * The check for a GC trigger is only performed when the current
4098 * region is full, so in most cases it's not needed. */
4103 struct thread *th=arch_os_get_current_thread();
4104 struct alloc_region *region=
4105 #ifdef LISP_FEATURE_SB_THREAD
4106 th ? &(th->alloc_region) : &boxed_region;
4111 void *new_free_pointer;
4112 gc_assert(nbytes>0);
4113 /* Check for alignment allocation problems. */
4114 gc_assert((((unsigned)region->free_pointer & LOWTAG_MASK) == 0)
4115 && ((nbytes & LOWTAG_MASK) == 0));
4118 /* there are a few places in the C code that allocate data in the
4119 * heap before Lisp starts. This is before interrupts are enabled,
4120 * so we don't need to check for pseudo-atomic */
4121 #ifdef LISP_FEATURE_SB_THREAD
4122 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4124 fprintf(stderr, "fatal error in thread 0x%x, tid=%ld\n",
4126 __asm__("movl %fs,%0" : "=r" (fs) : );
4127 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4128 debug_get_fs(),th->tls_cookie);
4129 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4132 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4136 /* maybe we can do this quickly ... */
4137 new_free_pointer = region->free_pointer + nbytes;
4138 if (new_free_pointer <= region->end_addr) {
4139 new_obj = (void*)(region->free_pointer);
4140 region->free_pointer = new_free_pointer;
4141 return(new_obj); /* yup */
4144 /* we have to go the long way around, it seems. Check whether
4145 * we should GC in the near future
4147 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4148 struct thread *thread=arch_os_get_current_thread();
4149 /* Don't flood the system with interrupts if the need to gc is
4150 * already noted. This can happen for example when SUB-GC
4151 * allocates or after a gc triggered in a WITHOUT-GCING. */
4152 if (SymbolValue(NEED_TO_COLLECT_GARBAGE,thread) == NIL) {
4153 /* set things up so that GC happens when we finish the PA
4154 * section. We only do this if there wasn't a pending
4155 * handler already, in case it was a gc. If it wasn't a
4156 * GC, the next allocation will get us back to this point
4157 * anyway, so no harm done
4159 struct interrupt_data *data=th->interrupt_data;
4160 sigset_t new_mask,old_mask;
4161 sigemptyset(&new_mask);
4162 sigaddset_blockable(&new_mask);
4163 thread_sigmask(SIG_BLOCK,&new_mask,&old_mask);
4165 if(!data->pending_handler) {
4166 if(!maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0))
4167 lose("Not in atomic: %d.\n",
4168 SymbolValue(PSEUDO_ATOMIC_ATOMIC,thread));
4169 /* Leave the signals blocked just as if it was
4170 * deferred the normal way and set the
4172 sigcopyset(&(data->pending_mask),&old_mask);
4173 SetSymbolValue(NEED_TO_COLLECT_GARBAGE,T,thread);
4175 thread_sigmask(SIG_SETMASK,&old_mask,0);
4179 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4184 * shared support for the OS-dependent signal handlers which
4185 * catch GENCGC-related write-protect violations
4188 void unhandled_sigmemoryfault(void);
4190 /* Depending on which OS we're running under, different signals might
4191 * be raised for a violation of write protection in the heap. This
4192 * function factors out the common generational GC magic which needs
4193 * to invoked in this case, and should be called from whatever signal
4194 * handler is appropriate for the OS we're running under.
4196 * Return true if this signal is a normal generational GC thing that
4197 * we were able to handle, or false if it was abnormal and control
4198 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4201 gencgc_handle_wp_violation(void* fault_addr)
4203 long page_index = find_page_index(fault_addr);
4205 #ifdef QSHOW_SIGNALS
4206 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4207 fault_addr, page_index));
4210 /* Check whether the fault is within the dynamic space. */
4211 if (page_index == (-1)) {
4213 /* It can be helpful to be able to put a breakpoint on this
4214 * case to help diagnose low-level problems. */
4215 unhandled_sigmemoryfault();
4217 /* not within the dynamic space -- not our responsibility */
4221 if (page_table[page_index].write_protected) {
4222 /* Unprotect the page. */
4223 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4224 page_table[page_index].write_protected_cleared = 1;
4225 page_table[page_index].write_protected = 0;
4227 /* The only acceptable reason for this signal on a heap
4228 * access is that GENCGC write-protected the page.
4229 * However, if two CPUs hit a wp page near-simultaneously,
4230 * we had better not have the second one lose here if it
4231 * does this test after the first one has already set wp=0
4233 if(page_table[page_index].write_protected_cleared != 1)
4234 lose("fault in heap page not marked as write-protected");
4236 /* Don't worry, we can handle it. */
4240 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4241 * it's not just a case of the program hitting the write barrier, and
4242 * are about to let Lisp deal with it. It's basically just a
4243 * convenient place to set a gdb breakpoint. */
4245 unhandled_sigmemoryfault()
4248 void gc_alloc_update_all_page_tables(void)
4250 /* Flush the alloc regions updating the tables. */
4253 gc_alloc_update_page_tables(0, &th->alloc_region);
4254 gc_alloc_update_page_tables(1, &unboxed_region);
4255 gc_alloc_update_page_tables(0, &boxed_region);
4258 gc_set_region_empty(struct alloc_region *region)
4260 region->first_page = 0;
4261 region->last_page = -1;
4262 region->start_addr = page_address(0);
4263 region->free_pointer = page_address(0);
4264 region->end_addr = page_address(0);