2 * GENerational Conservative Garbage Collector for SBCL x86
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 * For a review of garbage collection techniques (e.g. generational
18 * GC) and terminology (e.g. "scavenging") see Paul R. Wilson,
19 * "Uniprocessor Garbage Collection Techniques". As of 20000618, this
20 * had been accepted for _ACM Computing Surveys_ and was available
21 * as a PostScript preprint through
22 * <http://www.cs.utexas.edu/users/oops/papers.html>
24 * <ftp://ftp.cs.utexas.edu/pub/garbage/bigsurv.ps>.
36 #include "interrupt.h"
41 #include "gc-internal.h"
43 #include "genesis/vector.h"
44 #include "genesis/weak-pointer.h"
45 #include "genesis/simple-fun.h"
47 /* assembly language stub that executes trap_PendingInterrupt */
48 void do_pending_interrupt(void);
50 /* forward declarations */
51 int gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed);
52 static void gencgc_pickup_dynamic(void);
53 boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
60 /* the number of actual generations. (The number of 'struct
61 * generation' objects is one more than this, because one object
62 * serves as scratch when GC'ing.) */
63 #define NUM_GENERATIONS 6
65 /* Should we use page protection to help avoid the scavenging of pages
66 * that don't have pointers to younger generations? */
67 boolean enable_page_protection = 1;
69 /* Should we unmap a page and re-mmap it to have it zero filled? */
70 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
71 /* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
72 * so don't unmap there.
74 * The CMU CL comment didn't specify a version, but was probably an
75 * old version of FreeBSD (pre-4.0), so this might no longer be true.
76 * OTOH, if it is true, this behavior might exist on OpenBSD too, so
77 * for now we don't unmap there either. -- WHN 2001-04-07 */
78 boolean gencgc_unmap_zero = 0;
80 boolean gencgc_unmap_zero = 1;
83 /* the minimum size (in bytes) for a large object*/
84 unsigned large_object_size = 4 * PAGE_BYTES;
93 /* the verbosity level. All non-error messages are disabled at level 0;
94 * and only a few rare messages are printed at level 1. */
96 unsigned gencgc_verbose = 1;
98 unsigned gencgc_verbose = 0;
101 /* FIXME: At some point enable the various error-checking things below
102 * and see what they say. */
104 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
105 * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
106 int verify_gens = NUM_GENERATIONS;
108 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
109 boolean pre_verify_gen_0 = 0;
111 /* Should we check for bad pointers after gc_free_heap is called
112 * from Lisp PURIFY? */
113 boolean verify_after_free_heap = 0;
115 /* Should we print a note when code objects are found in the dynamic space
116 * during a heap verify? */
117 boolean verify_dynamic_code_check = 0;
119 /* Should we check code objects for fixup errors after they are transported? */
120 boolean check_code_fixups = 0;
122 /* Should we check that newly allocated regions are zero filled? */
123 boolean gencgc_zero_check = 0;
125 /* Should we check that the free space is zero filled? */
126 boolean gencgc_enable_verify_zero_fill = 0;
128 /* Should we check that free pages are zero filled during gc_free_heap
129 * called after Lisp PURIFY? */
130 boolean gencgc_zero_check_during_free_heap = 0;
133 * GC structures and variables
136 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
137 unsigned long bytes_allocated = 0;
138 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
139 unsigned long auto_gc_trigger = 0;
141 /* the source and destination generations. These are set before a GC starts
147 /* An array of page structures is statically allocated.
148 * This helps quickly map between an address its page structure.
149 * NUM_PAGES is set from the size of the dynamic space. */
150 struct page page_table[NUM_PAGES];
152 /* To map addresses to page structures the address of the first page
154 static void *heap_base = NULL;
157 /* Calculate the start address for the given page number. */
159 page_address(int page_num)
161 return (heap_base + (page_num * PAGE_BYTES));
164 /* Find the page index within the page_table for the given
165 * address. Return -1 on failure. */
167 find_page_index(void *addr)
169 int index = addr-heap_base;
172 index = ((unsigned int)index)/PAGE_BYTES;
173 if (index < NUM_PAGES)
180 /* a structure to hold the state of a generation */
183 /* the first page that gc_alloc() checks on its next call */
184 int alloc_start_page;
186 /* the first page that gc_alloc_unboxed() checks on its next call */
187 int alloc_unboxed_start_page;
189 /* the first page that gc_alloc_large (boxed) considers on its next
190 * call. (Although it always allocates after the boxed_region.) */
191 int alloc_large_start_page;
193 /* the first page that gc_alloc_large (unboxed) considers on its
194 * next call. (Although it always allocates after the
195 * current_unboxed_region.) */
196 int alloc_large_unboxed_start_page;
198 /* the bytes allocated to this generation */
201 /* the number of bytes at which to trigger a GC */
204 /* to calculate a new level for gc_trigger */
205 int bytes_consed_between_gc;
207 /* the number of GCs since the last raise */
210 /* the average age after which a GC will raise objects to the
214 /* the cumulative sum of the bytes allocated to this generation. It is
215 * cleared after a GC on this generations, and update before new
216 * objects are added from a GC of a younger generation. Dividing by
217 * the bytes_allocated will give the average age of the memory in
218 * this generation since its last GC. */
219 int cum_sum_bytes_allocated;
221 /* a minimum average memory age before a GC will occur helps
222 * prevent a GC when a large number of new live objects have been
223 * added, in which case a GC could be a waste of time */
224 double min_av_mem_age;
226 /* the number of actual generations. (The number of 'struct
227 * generation' objects is one more than this, because one object
228 * serves as scratch when GC'ing.) */
229 #define NUM_GENERATIONS 6
231 /* an array of generation structures. There needs to be one more
232 * generation structure than actual generations as the oldest
233 * generation is temporarily raised then lowered. */
234 struct generation generations[NUM_GENERATIONS+1];
236 /* the oldest generation that is will currently be GCed by default.
237 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
239 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
241 * Setting this to 0 effectively disables the generational nature of
242 * the GC. In some applications generational GC may not be useful
243 * because there are no long-lived objects.
245 * An intermediate value could be handy after moving long-lived data
246 * into an older generation so an unnecessary GC of this long-lived
247 * data can be avoided. */
248 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
250 /* The maximum free page in the heap is maintained and used to update
251 * ALLOCATION_POINTER which is used by the room function to limit its
252 * search of the heap. XX Gencgc obviously needs to be better
253 * integrated with the Lisp code. */
254 static int last_free_page;
256 /* This lock is to prevent multiple threads from simultaneously
257 * allocating new regions which overlap each other. Note that the
258 * majority of GC is single-threaded, but alloc() may be called from
259 * >1 thread at a time and must be thread-safe. This lock must be
260 * seized before all accesses to generations[] or to parts of
261 * page_table[] that other threads may want to see */
263 static lispobj free_pages_lock=0;
267 * miscellaneous heap functions
270 /* Count the number of pages which are write-protected within the
271 * given generation. */
273 count_write_protect_generation_pages(int generation)
278 for (i = 0; i < last_free_page; i++)
279 if ((page_table[i].allocated != FREE_PAGE_FLAG)
280 && (page_table[i].gen == generation)
281 && (page_table[i].write_protected == 1))
286 /* Count the number of pages within the given generation. */
288 count_generation_pages(int generation)
293 for (i = 0; i < last_free_page; i++)
294 if ((page_table[i].allocated != 0)
295 && (page_table[i].gen == generation))
302 count_dont_move_pages(void)
306 for (i = 0; i < last_free_page; i++) {
307 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
315 /* Work through the pages and add up the number of bytes used for the
316 * given generation. */
318 count_generation_bytes_allocated (int gen)
322 for (i = 0; i < last_free_page; i++) {
323 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
324 result += page_table[i].bytes_used;
329 /* Return the average age of the memory in a generation. */
331 gen_av_mem_age(int gen)
333 if (generations[gen].bytes_allocated == 0)
337 ((double)generations[gen].cum_sum_bytes_allocated)
338 / ((double)generations[gen].bytes_allocated);
341 void fpu_save(int *); /* defined in x86-assem.S */
342 void fpu_restore(int *); /* defined in x86-assem.S */
343 /* The verbose argument controls how much to print: 0 for normal
344 * level of detail; 1 for debugging. */
346 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
351 /* This code uses the FP instructions which may be set up for Lisp
352 * so they need to be saved and reset for C. */
355 /* number of generations to print */
357 gens = NUM_GENERATIONS+1;
359 gens = NUM_GENERATIONS;
361 /* Print the heap stats. */
363 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
365 for (i = 0; i < gens; i++) {
369 int large_boxed_cnt = 0;
370 int large_unboxed_cnt = 0;
373 for (j = 0; j < last_free_page; j++)
374 if (page_table[j].gen == i) {
376 /* Count the number of boxed pages within the given
378 if (page_table[j].allocated & BOXED_PAGE_FLAG) {
379 if (page_table[j].large_object)
384 if(page_table[j].dont_move) pinned_cnt++;
385 /* Count the number of unboxed pages within the given
387 if (page_table[j].allocated & UNBOXED_PAGE_FLAG) {
388 if (page_table[j].large_object)
395 gc_assert(generations[i].bytes_allocated
396 == count_generation_bytes_allocated(i));
398 " %1d: %5d %5d %5d %5d %5d %8d %5d %8d %4d %3d %7.4f\n",
400 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
402 generations[i].bytes_allocated,
403 (count_generation_pages(i)*PAGE_BYTES
404 - generations[i].bytes_allocated),
405 generations[i].gc_trigger,
406 count_write_protect_generation_pages(i),
407 generations[i].num_gc,
410 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
412 fpu_restore(fpu_state);
416 * allocation routines
420 * To support quick and inline allocation, regions of memory can be
421 * allocated and then allocated from with just a free pointer and a
422 * check against an end address.
424 * Since objects can be allocated to spaces with different properties
425 * e.g. boxed/unboxed, generation, ages; there may need to be many
426 * allocation regions.
428 * Each allocation region may be start within a partly used page. Many
429 * features of memory use are noted on a page wise basis, e.g. the
430 * generation; so if a region starts within an existing allocated page
431 * it must be consistent with this page.
433 * During the scavenging of the newspace, objects will be transported
434 * into an allocation region, and pointers updated to point to this
435 * allocation region. It is possible that these pointers will be
436 * scavenged again before the allocation region is closed, e.g. due to
437 * trans_list which jumps all over the place to cleanup the list. It
438 * is important to be able to determine properties of all objects
439 * pointed to when scavenging, e.g to detect pointers to the oldspace.
440 * Thus it's important that the allocation regions have the correct
441 * properties set when allocated, and not just set when closed. The
442 * region allocation routines return regions with the specified
443 * properties, and grab all the pages, setting their properties
444 * appropriately, except that the amount used is not known.
446 * These regions are used to support quicker allocation using just a
447 * free pointer. The actual space used by the region is not reflected
448 * in the pages tables until it is closed. It can't be scavenged until
451 * When finished with the region it should be closed, which will
452 * update the page tables for the actual space used returning unused
453 * space. Further it may be noted in the new regions which is
454 * necessary when scavenging the newspace.
456 * Large objects may be allocated directly without an allocation
457 * region, the page tables are updated immediately.
459 * Unboxed objects don't contain pointers to other objects and so
460 * don't need scavenging. Further they can't contain pointers to
461 * younger generations so WP is not needed. By allocating pages to
462 * unboxed objects the whole page never needs scavenging or
463 * write-protecting. */
465 /* We are only using two regions at present. Both are for the current
466 * newspace generation. */
467 struct alloc_region boxed_region;
468 struct alloc_region unboxed_region;
470 /* The generation currently being allocated to. */
471 static int gc_alloc_generation;
473 /* Find a new region with room for at least the given number of bytes.
475 * It starts looking at the current generation's alloc_start_page. So
476 * may pick up from the previous region if there is enough space. This
477 * keeps the allocation contiguous when scavenging the newspace.
479 * The alloc_region should have been closed by a call to
480 * gc_alloc_update_page_tables(), and will thus be in an empty state.
482 * To assist the scavenging functions write-protected pages are not
483 * used. Free pages should not be write-protected.
485 * It is critical to the conservative GC that the start of regions be
486 * known. To help achieve this only small regions are allocated at a
489 * During scavenging, pointers may be found to within the current
490 * region and the page generation must be set so that pointers to the
491 * from space can be recognized. Therefore the generation of pages in
492 * the region are set to gc_alloc_generation. To prevent another
493 * allocation call using the same pages, all the pages in the region
494 * are allocated, although they will initially be empty.
497 gc_alloc_new_region(int nbytes, int unboxed, struct alloc_region *alloc_region)
506 "/alloc_new_region for %d bytes from gen %d\n",
507 nbytes, gc_alloc_generation));
510 /* Check that the region is in a reset state. */
511 gc_assert((alloc_region->first_page == 0)
512 && (alloc_region->last_page == -1)
513 && (alloc_region->free_pointer == alloc_region->end_addr));
514 get_spinlock(&free_pages_lock,(int) alloc_region);
517 generations[gc_alloc_generation].alloc_unboxed_start_page;
520 generations[gc_alloc_generation].alloc_start_page;
522 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
523 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
524 + PAGE_BYTES*(last_page-first_page);
526 /* Set up the alloc_region. */
527 alloc_region->first_page = first_page;
528 alloc_region->last_page = last_page;
529 alloc_region->start_addr = page_table[first_page].bytes_used
530 + page_address(first_page);
531 alloc_region->free_pointer = alloc_region->start_addr;
532 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
534 /* Set up the pages. */
536 /* The first page may have already been in use. */
537 if (page_table[first_page].bytes_used == 0) {
539 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
541 page_table[first_page].allocated = BOXED_PAGE_FLAG;
542 page_table[first_page].gen = gc_alloc_generation;
543 page_table[first_page].large_object = 0;
544 page_table[first_page].first_object_offset = 0;
548 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
550 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
551 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
553 gc_assert(page_table[first_page].gen == gc_alloc_generation);
554 gc_assert(page_table[first_page].large_object == 0);
556 for (i = first_page+1; i <= last_page; i++) {
558 page_table[i].allocated = UNBOXED_PAGE_FLAG;
560 page_table[i].allocated = BOXED_PAGE_FLAG;
561 page_table[i].gen = gc_alloc_generation;
562 page_table[i].large_object = 0;
563 /* This may not be necessary for unboxed regions (think it was
565 page_table[i].first_object_offset =
566 alloc_region->start_addr - page_address(i);
567 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
569 /* Bump up last_free_page. */
570 if (last_page+1 > last_free_page) {
571 last_free_page = last_page+1;
572 SetSymbolValue(ALLOCATION_POINTER,
573 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
576 release_spinlock(&free_pages_lock);
578 /* we can do this after releasing free_pages_lock */
579 if (gencgc_zero_check) {
581 for (p = (int *)alloc_region->start_addr;
582 p < (int *)alloc_region->end_addr; p++) {
584 /* KLUDGE: It would be nice to use %lx and explicit casts
585 * (long) in code like this, so that it is less likely to
586 * break randomly when running on a machine with different
587 * word sizes. -- WHN 19991129 */
588 lose("The new region at %x is not zero.", p);
595 /* If the record_new_objects flag is 2 then all new regions created
598 * If it's 1 then then it is only recorded if the first page of the
599 * current region is <= new_areas_ignore_page. This helps avoid
600 * unnecessary recording when doing full scavenge pass.
602 * The new_object structure holds the page, byte offset, and size of
603 * new regions of objects. Each new area is placed in the array of
604 * these structures pointer to by new_areas. new_areas_index holds the
605 * offset into new_areas.
607 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
608 * later code must detect this and handle it, probably by doing a full
609 * scavenge of a generation. */
610 #define NUM_NEW_AREAS 512
611 static int record_new_objects = 0;
612 static int new_areas_ignore_page;
618 static struct new_area (*new_areas)[];
619 static int new_areas_index;
622 /* Add a new area to new_areas. */
624 add_new_area(int first_page, int offset, int size)
626 unsigned new_area_start,c;
629 /* Ignore if full. */
630 if (new_areas_index >= NUM_NEW_AREAS)
633 switch (record_new_objects) {
637 if (first_page > new_areas_ignore_page)
646 new_area_start = PAGE_BYTES*first_page + offset;
648 /* Search backwards for a prior area that this follows from. If
649 found this will save adding a new area. */
650 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
652 PAGE_BYTES*((*new_areas)[i].page)
653 + (*new_areas)[i].offset
654 + (*new_areas)[i].size;
656 "/add_new_area S1 %d %d %d %d\n",
657 i, c, new_area_start, area_end));*/
658 if (new_area_start == area_end) {
660 "/adding to [%d] %d %d %d with %d %d %d:\n",
662 (*new_areas)[i].page,
663 (*new_areas)[i].offset,
664 (*new_areas)[i].size,
668 (*new_areas)[i].size += size;
673 (*new_areas)[new_areas_index].page = first_page;
674 (*new_areas)[new_areas_index].offset = offset;
675 (*new_areas)[new_areas_index].size = size;
677 "/new_area %d page %d offset %d size %d\n",
678 new_areas_index, first_page, offset, size));*/
681 /* Note the max new_areas used. */
682 if (new_areas_index > max_new_areas)
683 max_new_areas = new_areas_index;
686 /* Update the tables for the alloc_region. The region may be added to
689 * When done the alloc_region is set up so that the next quick alloc
690 * will fail safely and thus a new region will be allocated. Further
691 * it is safe to try to re-update the page table of this reset
694 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
700 int orig_first_page_bytes_used;
705 first_page = alloc_region->first_page;
707 /* Catch an unused alloc_region. */
708 if ((first_page == 0) && (alloc_region->last_page == -1))
711 next_page = first_page+1;
713 get_spinlock(&free_pages_lock,(int) alloc_region);
714 if (alloc_region->free_pointer != alloc_region->start_addr) {
715 /* some bytes were allocated in the region */
716 orig_first_page_bytes_used = page_table[first_page].bytes_used;
718 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
720 /* All the pages used need to be updated */
722 /* Update the first page. */
724 /* If the page was free then set up the gen, and
725 * first_object_offset. */
726 if (page_table[first_page].bytes_used == 0)
727 gc_assert(page_table[first_page].first_object_offset == 0);
728 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
731 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
733 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
734 gc_assert(page_table[first_page].gen == gc_alloc_generation);
735 gc_assert(page_table[first_page].large_object == 0);
739 /* Calculate the number of bytes used in this page. This is not
740 * always the number of new bytes, unless it was free. */
742 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
743 bytes_used = PAGE_BYTES;
746 page_table[first_page].bytes_used = bytes_used;
747 byte_cnt += bytes_used;
750 /* All the rest of the pages should be free. We need to set their
751 * first_object_offset pointer to the start of the region, and set
754 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
756 gc_assert(page_table[next_page].allocated==UNBOXED_PAGE_FLAG);
758 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
759 gc_assert(page_table[next_page].bytes_used == 0);
760 gc_assert(page_table[next_page].gen == gc_alloc_generation);
761 gc_assert(page_table[next_page].large_object == 0);
763 gc_assert(page_table[next_page].first_object_offset ==
764 alloc_region->start_addr - page_address(next_page));
766 /* Calculate the number of bytes used in this page. */
768 if ((bytes_used = (alloc_region->free_pointer
769 - page_address(next_page)))>PAGE_BYTES) {
770 bytes_used = PAGE_BYTES;
773 page_table[next_page].bytes_used = bytes_used;
774 byte_cnt += bytes_used;
779 region_size = alloc_region->free_pointer - alloc_region->start_addr;
780 bytes_allocated += region_size;
781 generations[gc_alloc_generation].bytes_allocated += region_size;
783 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
785 /* Set the generations alloc restart page to the last page of
788 generations[gc_alloc_generation].alloc_unboxed_start_page =
791 generations[gc_alloc_generation].alloc_start_page = next_page-1;
793 /* Add the region to the new_areas if requested. */
795 add_new_area(first_page,orig_first_page_bytes_used, region_size);
799 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
801 gc_alloc_generation));
804 /* There are no bytes allocated. Unallocate the first_page if
805 * there are 0 bytes_used. */
806 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
807 if (page_table[first_page].bytes_used == 0)
808 page_table[first_page].allocated = FREE_PAGE_FLAG;
811 /* Unallocate any unused pages. */
812 while (next_page <= alloc_region->last_page) {
813 gc_assert(page_table[next_page].bytes_used == 0);
814 page_table[next_page].allocated = FREE_PAGE_FLAG;
817 release_spinlock(&free_pages_lock);
818 /* alloc_region is per-thread, we're ok to do this unlocked */
819 gc_set_region_empty(alloc_region);
822 static inline void *gc_quick_alloc(int nbytes);
824 /* Allocate a possibly large object. */
826 gc_alloc_large(int nbytes, int unboxed, struct alloc_region *alloc_region)
830 int orig_first_page_bytes_used;
836 get_spinlock(&free_pages_lock,(int) alloc_region);
840 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
842 first_page = generations[gc_alloc_generation].alloc_large_start_page;
844 if (first_page <= alloc_region->last_page) {
845 first_page = alloc_region->last_page+1;
848 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
850 gc_assert(first_page > alloc_region->last_page);
852 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
855 generations[gc_alloc_generation].alloc_large_start_page = last_page;
857 /* Set up the pages. */
858 orig_first_page_bytes_used = page_table[first_page].bytes_used;
860 /* If the first page was free then set up the gen, and
861 * first_object_offset. */
862 if (page_table[first_page].bytes_used == 0) {
864 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
866 page_table[first_page].allocated = BOXED_PAGE_FLAG;
867 page_table[first_page].gen = gc_alloc_generation;
868 page_table[first_page].first_object_offset = 0;
869 page_table[first_page].large_object = 1;
873 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
875 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
876 gc_assert(page_table[first_page].gen == gc_alloc_generation);
877 gc_assert(page_table[first_page].large_object == 1);
881 /* Calc. the number of bytes used in this page. This is not
882 * always the number of new bytes, unless it was free. */
884 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
885 bytes_used = PAGE_BYTES;
888 page_table[first_page].bytes_used = bytes_used;
889 byte_cnt += bytes_used;
891 next_page = first_page+1;
893 /* All the rest of the pages should be free. We need to set their
894 * first_object_offset pointer to the start of the region, and
895 * set the bytes_used. */
897 gc_assert(page_table[next_page].allocated == FREE_PAGE_FLAG);
898 gc_assert(page_table[next_page].bytes_used == 0);
900 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
902 page_table[next_page].allocated = BOXED_PAGE_FLAG;
903 page_table[next_page].gen = gc_alloc_generation;
904 page_table[next_page].large_object = 1;
906 page_table[next_page].first_object_offset =
907 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
909 /* Calculate the number of bytes used in this page. */
911 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
912 bytes_used = PAGE_BYTES;
915 page_table[next_page].bytes_used = bytes_used;
916 page_table[next_page].write_protected=0;
917 page_table[next_page].dont_move=0;
918 byte_cnt += bytes_used;
922 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
924 bytes_allocated += nbytes;
925 generations[gc_alloc_generation].bytes_allocated += nbytes;
927 /* Add the region to the new_areas if requested. */
929 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
931 /* Bump up last_free_page */
932 if (last_page+1 > last_free_page) {
933 last_free_page = last_page+1;
934 SetSymbolValue(ALLOCATION_POINTER,
935 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
937 release_spinlock(&free_pages_lock);
939 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
943 gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed)
948 int restart_page=*restart_page_ptr;
951 int large_p=(nbytes>=large_object_size);
952 gc_assert(free_pages_lock);
954 /* Search for a contiguous free space of at least nbytes. If it's
955 * a large object then align it on a page boundary by searching
956 * for a free page. */
959 first_page = restart_page;
961 while ((first_page < NUM_PAGES)
962 && (page_table[first_page].allocated != FREE_PAGE_FLAG))
965 while (first_page < NUM_PAGES) {
966 if(page_table[first_page].allocated == FREE_PAGE_FLAG)
968 if((page_table[first_page].allocated ==
969 (unboxed ? UNBOXED_PAGE_FLAG : BOXED_PAGE_FLAG)) &&
970 (page_table[first_page].large_object == 0) &&
971 (page_table[first_page].gen == gc_alloc_generation) &&
972 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
973 (page_table[first_page].write_protected == 0) &&
974 (page_table[first_page].dont_move == 0)) {
980 if (first_page >= NUM_PAGES) {
982 "Argh! gc_find_free_space failed (first_page), nbytes=%d.\n",
984 print_generation_stats(1);
988 gc_assert(page_table[first_page].write_protected == 0);
990 last_page = first_page;
991 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
993 while (((bytes_found < nbytes)
994 || (!large_p && (num_pages < 2)))
995 && (last_page < (NUM_PAGES-1))
996 && (page_table[last_page+1].allocated == FREE_PAGE_FLAG)) {
999 bytes_found += PAGE_BYTES;
1000 gc_assert(page_table[last_page].write_protected == 0);
1003 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
1004 + PAGE_BYTES*(last_page-first_page);
1006 gc_assert(bytes_found == region_size);
1007 restart_page = last_page + 1;
1008 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
1010 /* Check for a failure */
1011 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
1013 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%d.\n",
1015 print_generation_stats(1);
1018 *restart_page_ptr=first_page;
1022 /* Allocate bytes. All the rest of the special-purpose allocation
1023 * functions will eventually call this */
1026 gc_alloc_with_region(int nbytes,int unboxed_p, struct alloc_region *my_region,
1029 void *new_free_pointer;
1031 if(nbytes>=large_object_size)
1032 return gc_alloc_large(nbytes,unboxed_p,my_region);
1034 /* Check whether there is room in the current alloc region. */
1035 new_free_pointer = my_region->free_pointer + nbytes;
1037 if (new_free_pointer <= my_region->end_addr) {
1038 /* If so then allocate from the current alloc region. */
1039 void *new_obj = my_region->free_pointer;
1040 my_region->free_pointer = new_free_pointer;
1042 /* Unless a `quick' alloc was requested, check whether the
1043 alloc region is almost empty. */
1045 (my_region->end_addr - my_region->free_pointer) <= 32) {
1046 /* If so, finished with the current region. */
1047 gc_alloc_update_page_tables(unboxed_p, my_region);
1048 /* Set up a new region. */
1049 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1052 return((void *)new_obj);
1055 /* Else not enough free space in the current region: retry with a
1058 gc_alloc_update_page_tables(unboxed_p, my_region);
1059 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1060 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1063 /* these are only used during GC: all allocation from the mutator calls
1064 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1068 gc_general_alloc(int nbytes,int unboxed_p,int quick_p)
1070 struct alloc_region *my_region =
1071 unboxed_p ? &unboxed_region : &boxed_region;
1072 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1075 static inline void *
1076 gc_quick_alloc(int nbytes)
1078 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1081 static inline void *
1082 gc_quick_alloc_large(int nbytes)
1084 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1087 static inline void *
1088 gc_alloc_unboxed(int nbytes)
1090 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1093 static inline void *
1094 gc_quick_alloc_unboxed(int nbytes)
1096 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1099 static inline void *
1100 gc_quick_alloc_large_unboxed(int nbytes)
1102 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1106 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1109 extern int (*scavtab[256])(lispobj *where, lispobj object);
1110 extern lispobj (*transother[256])(lispobj object);
1111 extern int (*sizetab[256])(lispobj *where);
1113 /* Copy a large boxed object. If the object is in a large object
1114 * region then it is simply promoted, else it is copied. If it's large
1115 * enough then it's copied to a large object region.
1117 * Vectors may have shrunk. If the object is not copied the space
1118 * needs to be reclaimed, and the page_tables corrected. */
1120 copy_large_object(lispobj object, int nwords)
1126 gc_assert(is_lisp_pointer(object));
1127 gc_assert(from_space_p(object));
1128 gc_assert((nwords & 0x01) == 0);
1131 /* Check whether it's in a large object region. */
1132 first_page = find_page_index((void *)object);
1133 gc_assert(first_page >= 0);
1135 if (page_table[first_page].large_object) {
1137 /* Promote the object. */
1139 int remaining_bytes;
1144 /* Note: Any page write-protection must be removed, else a
1145 * later scavenge_newspace may incorrectly not scavenge these
1146 * pages. This would not be necessary if they are added to the
1147 * new areas, but let's do it for them all (they'll probably
1148 * be written anyway?). */
1150 gc_assert(page_table[first_page].first_object_offset == 0);
1152 next_page = first_page;
1153 remaining_bytes = nwords*4;
1154 while (remaining_bytes > PAGE_BYTES) {
1155 gc_assert(page_table[next_page].gen == from_space);
1156 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1157 gc_assert(page_table[next_page].large_object);
1158 gc_assert(page_table[next_page].first_object_offset==
1159 -PAGE_BYTES*(next_page-first_page));
1160 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1162 page_table[next_page].gen = new_space;
1164 /* Remove any write-protection. We should be able to rely
1165 * on the write-protect flag to avoid redundant calls. */
1166 if (page_table[next_page].write_protected) {
1167 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1168 page_table[next_page].write_protected = 0;
1170 remaining_bytes -= PAGE_BYTES;
1174 /* Now only one page remains, but the object may have shrunk
1175 * so there may be more unused pages which will be freed. */
1177 /* The object may have shrunk but shouldn't have grown. */
1178 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1180 page_table[next_page].gen = new_space;
1181 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1183 /* Adjust the bytes_used. */
1184 old_bytes_used = page_table[next_page].bytes_used;
1185 page_table[next_page].bytes_used = remaining_bytes;
1187 bytes_freed = old_bytes_used - remaining_bytes;
1189 /* Free any remaining pages; needs care. */
1191 while ((old_bytes_used == PAGE_BYTES) &&
1192 (page_table[next_page].gen == from_space) &&
1193 (page_table[next_page].allocated == BOXED_PAGE_FLAG) &&
1194 page_table[next_page].large_object &&
1195 (page_table[next_page].first_object_offset ==
1196 -(next_page - first_page)*PAGE_BYTES)) {
1197 /* Checks out OK, free the page. Don't need to bother zeroing
1198 * pages as this should have been done before shrinking the
1199 * object. These pages shouldn't be write-protected as they
1200 * should be zero filled. */
1201 gc_assert(page_table[next_page].write_protected == 0);
1203 old_bytes_used = page_table[next_page].bytes_used;
1204 page_table[next_page].allocated = FREE_PAGE_FLAG;
1205 page_table[next_page].bytes_used = 0;
1206 bytes_freed += old_bytes_used;
1210 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1211 generations[new_space].bytes_allocated += 4*nwords;
1212 bytes_allocated -= bytes_freed;
1214 /* Add the region to the new_areas if requested. */
1215 add_new_area(first_page,0,nwords*4);
1219 /* Get tag of object. */
1220 tag = lowtag_of(object);
1222 /* Allocate space. */
1223 new = gc_quick_alloc_large(nwords*4);
1225 memcpy(new,native_pointer(object),nwords*4);
1227 /* Return Lisp pointer of new object. */
1228 return ((lispobj) new) | tag;
1232 /* to copy unboxed objects */
1234 copy_unboxed_object(lispobj object, int nwords)
1239 gc_assert(is_lisp_pointer(object));
1240 gc_assert(from_space_p(object));
1241 gc_assert((nwords & 0x01) == 0);
1243 /* Get tag of object. */
1244 tag = lowtag_of(object);
1246 /* Allocate space. */
1247 new = gc_quick_alloc_unboxed(nwords*4);
1249 memcpy(new,native_pointer(object),nwords*4);
1251 /* Return Lisp pointer of new object. */
1252 return ((lispobj) new) | tag;
1255 /* to copy large unboxed objects
1257 * If the object is in a large object region then it is simply
1258 * promoted, else it is copied. If it's large enough then it's copied
1259 * to a large object region.
1261 * Bignums and vectors may have shrunk. If the object is not copied
1262 * the space needs to be reclaimed, and the page_tables corrected.
1264 * KLUDGE: There's a lot of cut-and-paste duplication between this
1265 * function and copy_large_object(..). -- WHN 20000619 */
1267 copy_large_unboxed_object(lispobj object, int nwords)
1271 lispobj *source, *dest;
1274 gc_assert(is_lisp_pointer(object));
1275 gc_assert(from_space_p(object));
1276 gc_assert((nwords & 0x01) == 0);
1278 if ((nwords > 1024*1024) && gencgc_verbose)
1279 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*4));
1281 /* Check whether it's a large object. */
1282 first_page = find_page_index((void *)object);
1283 gc_assert(first_page >= 0);
1285 if (page_table[first_page].large_object) {
1286 /* Promote the object. Note: Unboxed objects may have been
1287 * allocated to a BOXED region so it may be necessary to
1288 * change the region to UNBOXED. */
1289 int remaining_bytes;
1294 gc_assert(page_table[first_page].first_object_offset == 0);
1296 next_page = first_page;
1297 remaining_bytes = nwords*4;
1298 while (remaining_bytes > PAGE_BYTES) {
1299 gc_assert(page_table[next_page].gen == from_space);
1300 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1301 || (page_table[next_page].allocated == BOXED_PAGE_FLAG));
1302 gc_assert(page_table[next_page].large_object);
1303 gc_assert(page_table[next_page].first_object_offset==
1304 -PAGE_BYTES*(next_page-first_page));
1305 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1307 page_table[next_page].gen = new_space;
1308 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1309 remaining_bytes -= PAGE_BYTES;
1313 /* Now only one page remains, but the object may have shrunk so
1314 * there may be more unused pages which will be freed. */
1316 /* Object may have shrunk but shouldn't have grown - check. */
1317 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1319 page_table[next_page].gen = new_space;
1320 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1322 /* Adjust the bytes_used. */
1323 old_bytes_used = page_table[next_page].bytes_used;
1324 page_table[next_page].bytes_used = remaining_bytes;
1326 bytes_freed = old_bytes_used - remaining_bytes;
1328 /* Free any remaining pages; needs care. */
1330 while ((old_bytes_used == PAGE_BYTES) &&
1331 (page_table[next_page].gen == from_space) &&
1332 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1333 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
1334 page_table[next_page].large_object &&
1335 (page_table[next_page].first_object_offset ==
1336 -(next_page - first_page)*PAGE_BYTES)) {
1337 /* Checks out OK, free the page. Don't need to both zeroing
1338 * pages as this should have been done before shrinking the
1339 * object. These pages shouldn't be write-protected, even if
1340 * boxed they should be zero filled. */
1341 gc_assert(page_table[next_page].write_protected == 0);
1343 old_bytes_used = page_table[next_page].bytes_used;
1344 page_table[next_page].allocated = FREE_PAGE_FLAG;
1345 page_table[next_page].bytes_used = 0;
1346 bytes_freed += old_bytes_used;
1350 if ((bytes_freed > 0) && gencgc_verbose)
1352 "/copy_large_unboxed bytes_freed=%d\n",
1355 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1356 generations[new_space].bytes_allocated += 4*nwords;
1357 bytes_allocated -= bytes_freed;
1362 /* Get tag of object. */
1363 tag = lowtag_of(object);
1365 /* Allocate space. */
1366 new = gc_quick_alloc_large_unboxed(nwords*4);
1369 source = (lispobj *) native_pointer(object);
1371 /* Copy the object. */
1372 while (nwords > 0) {
1373 dest[0] = source[0];
1374 dest[1] = source[1];
1380 /* Return Lisp pointer of new object. */
1381 return ((lispobj) new) | tag;
1390 * code and code-related objects
1393 static lispobj trans_fun_header(lispobj object);
1394 static lispobj trans_boxed(lispobj object);
1397 /* Scan a x86 compiled code object, looking for possible fixups that
1398 * have been missed after a move.
1400 * Two types of fixups are needed:
1401 * 1. Absolute fixups to within the code object.
1402 * 2. Relative fixups to outside the code object.
1404 * Currently only absolute fixups to the constant vector, or to the
1405 * code area are checked. */
1407 sniff_code_object(struct code *code, unsigned displacement)
1409 int nheader_words, ncode_words, nwords;
1411 void *constants_start_addr, *constants_end_addr;
1412 void *code_start_addr, *code_end_addr;
1413 int fixup_found = 0;
1415 if (!check_code_fixups)
1418 ncode_words = fixnum_value(code->code_size);
1419 nheader_words = HeaderValue(*(lispobj *)code);
1420 nwords = ncode_words + nheader_words;
1422 constants_start_addr = (void *)code + 5*4;
1423 constants_end_addr = (void *)code + nheader_words*4;
1424 code_start_addr = (void *)code + nheader_words*4;
1425 code_end_addr = (void *)code + nwords*4;
1427 /* Work through the unboxed code. */
1428 for (p = code_start_addr; p < code_end_addr; p++) {
1429 void *data = *(void **)p;
1430 unsigned d1 = *((unsigned char *)p - 1);
1431 unsigned d2 = *((unsigned char *)p - 2);
1432 unsigned d3 = *((unsigned char *)p - 3);
1433 unsigned d4 = *((unsigned char *)p - 4);
1435 unsigned d5 = *((unsigned char *)p - 5);
1436 unsigned d6 = *((unsigned char *)p - 6);
1439 /* Check for code references. */
1440 /* Check for a 32 bit word that looks like an absolute
1441 reference to within the code adea of the code object. */
1442 if ((data >= (code_start_addr-displacement))
1443 && (data < (code_end_addr-displacement))) {
1444 /* function header */
1446 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) == (unsigned)code)) {
1447 /* Skip the function header */
1451 /* the case of PUSH imm32 */
1455 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1456 p, d6, d5, d4, d3, d2, d1, data));
1457 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1459 /* the case of MOV [reg-8],imm32 */
1461 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1462 || d2==0x45 || d2==0x46 || d2==0x47)
1466 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1467 p, d6, d5, d4, d3, d2, d1, data));
1468 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1470 /* the case of LEA reg,[disp32] */
1471 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1474 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1475 p, d6, d5, d4, d3, d2, d1, data));
1476 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1480 /* Check for constant references. */
1481 /* Check for a 32 bit word that looks like an absolute
1482 reference to within the constant vector. Constant references
1484 if ((data >= (constants_start_addr-displacement))
1485 && (data < (constants_end_addr-displacement))
1486 && (((unsigned)data & 0x3) == 0)) {
1491 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1492 p, d6, d5, d4, d3, d2, d1, data));
1493 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1496 /* the case of MOV m32,EAX */
1500 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1501 p, d6, d5, d4, d3, d2, d1, data));
1502 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1505 /* the case of CMP m32,imm32 */
1506 if ((d1 == 0x3d) && (d2 == 0x81)) {
1509 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1510 p, d6, d5, d4, d3, d2, d1, data));
1512 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1515 /* Check for a mod=00, r/m=101 byte. */
1516 if ((d1 & 0xc7) == 5) {
1521 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1522 p, d6, d5, d4, d3, d2, d1, data));
1523 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1525 /* the case of CMP reg32,m32 */
1529 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1530 p, d6, d5, d4, d3, d2, d1, data));
1531 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1533 /* the case of MOV m32,reg32 */
1537 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1538 p, d6, d5, d4, d3, d2, d1, data));
1539 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1541 /* the case of MOV reg32,m32 */
1545 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1546 p, d6, d5, d4, d3, d2, d1, data));
1547 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1549 /* the case of LEA reg32,m32 */
1553 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1554 p, d6, d5, d4, d3, d2, d1, data));
1555 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1561 /* If anything was found, print some information on the code
1565 "/compiled code object at %x: header words = %d, code words = %d\n",
1566 code, nheader_words, ncode_words));
1568 "/const start = %x, end = %x\n",
1569 constants_start_addr, constants_end_addr));
1571 "/code start = %x, end = %x\n",
1572 code_start_addr, code_end_addr));
1577 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1579 int nheader_words, ncode_words, nwords;
1580 void *constants_start_addr, *constants_end_addr;
1581 void *code_start_addr, *code_end_addr;
1582 lispobj fixups = NIL;
1583 unsigned displacement = (unsigned)new_code - (unsigned)old_code;
1584 struct vector *fixups_vector;
1586 ncode_words = fixnum_value(new_code->code_size);
1587 nheader_words = HeaderValue(*(lispobj *)new_code);
1588 nwords = ncode_words + nheader_words;
1590 "/compiled code object at %x: header words = %d, code words = %d\n",
1591 new_code, nheader_words, ncode_words)); */
1592 constants_start_addr = (void *)new_code + 5*4;
1593 constants_end_addr = (void *)new_code + nheader_words*4;
1594 code_start_addr = (void *)new_code + nheader_words*4;
1595 code_end_addr = (void *)new_code + nwords*4;
1598 "/const start = %x, end = %x\n",
1599 constants_start_addr,constants_end_addr));
1601 "/code start = %x; end = %x\n",
1602 code_start_addr,code_end_addr));
1605 /* The first constant should be a pointer to the fixups for this
1606 code objects. Check. */
1607 fixups = new_code->constants[0];
1609 /* It will be 0 or the unbound-marker if there are no fixups (as
1610 * will be the case if the code object has been purified, for
1611 * example) and will be an other pointer if it is valid. */
1612 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1613 !is_lisp_pointer(fixups)) {
1614 /* Check for possible errors. */
1615 if (check_code_fixups)
1616 sniff_code_object(new_code, displacement);
1621 fixups_vector = (struct vector *)native_pointer(fixups);
1623 /* Could be pointing to a forwarding pointer. */
1624 /* FIXME is this always in from_space? if so, could replace this code with
1625 * forwarding_pointer_p/forwarding_pointer_value */
1626 if (is_lisp_pointer(fixups) &&
1627 (find_page_index((void*)fixups_vector) != -1) &&
1628 (fixups_vector->header == 0x01)) {
1629 /* If so, then follow it. */
1630 /*SHOW("following pointer to a forwarding pointer");*/
1631 fixups_vector = (struct vector *)native_pointer((lispobj)fixups_vector->length);
1634 /*SHOW("got fixups");*/
1636 if (widetag_of(fixups_vector->header) ==
1637 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
1638 /* Got the fixups for the code block. Now work through the vector,
1639 and apply a fixup at each address. */
1640 int length = fixnum_value(fixups_vector->length);
1642 for (i = 0; i < length; i++) {
1643 unsigned offset = fixups_vector->data[i];
1644 /* Now check the current value of offset. */
1645 unsigned old_value =
1646 *(unsigned *)((unsigned)code_start_addr + offset);
1648 /* If it's within the old_code object then it must be an
1649 * absolute fixup (relative ones are not saved) */
1650 if ((old_value >= (unsigned)old_code)
1651 && (old_value < ((unsigned)old_code + nwords*4)))
1652 /* So add the dispacement. */
1653 *(unsigned *)((unsigned)code_start_addr + offset) =
1654 old_value + displacement;
1656 /* It is outside the old code object so it must be a
1657 * relative fixup (absolute fixups are not saved). So
1658 * subtract the displacement. */
1659 *(unsigned *)((unsigned)code_start_addr + offset) =
1660 old_value - displacement;
1664 /* Check for possible errors. */
1665 if (check_code_fixups) {
1666 sniff_code_object(new_code,displacement);
1672 trans_boxed_large(lispobj object)
1675 unsigned long length;
1677 gc_assert(is_lisp_pointer(object));
1679 header = *((lispobj *) native_pointer(object));
1680 length = HeaderValue(header) + 1;
1681 length = CEILING(length, 2);
1683 return copy_large_object(object, length);
1688 trans_unboxed_large(lispobj object)
1691 unsigned long length;
1694 gc_assert(is_lisp_pointer(object));
1696 header = *((lispobj *) native_pointer(object));
1697 length = HeaderValue(header) + 1;
1698 length = CEILING(length, 2);
1700 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 int kv_length;
1717 unsigned int length = 0; /* (0 = dummy to stop GCC warning) */
1718 lispobj *hash_table;
1719 lispobj empty_symbol;
1720 unsigned int *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1721 unsigned int *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1722 unsigned int *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 = (lispobj *)native_pointer(where[2]);
1750 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1751 if (widetag_of(hash_table[0]) != INSTANCE_HEADER_WIDETAG) {
1752 lose("hash table not instance (%x at %x)", hash_table[0], hash_table);
1755 /* Scavenge element 1, which should be some internal symbol that
1756 * the hash table code reserves for marking empty slots. */
1757 scavenge(where+3, 1);
1758 if (!is_lisp_pointer(where[3])) {
1759 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1761 empty_symbol = where[3];
1762 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1763 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1764 SYMBOL_HEADER_WIDETAG) {
1765 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1766 *(lispobj *)native_pointer(empty_symbol));
1769 /* Scavenge hash table, which will fix the positions of the other
1770 * needed objects. */
1771 scavenge(hash_table, 16);
1773 /* Cross-check the kv_vector. */
1774 if (where != (lispobj *)native_pointer(hash_table[9])) {
1775 lose("hash_table table!=this table %x", hash_table[9]);
1779 weak_p_obj = hash_table[10];
1783 lispobj index_vector_obj = hash_table[13];
1785 if (is_lisp_pointer(index_vector_obj) &&
1786 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1787 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1788 index_vector = ((unsigned int *)native_pointer(index_vector_obj)) + 2;
1789 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1790 length = fixnum_value(((unsigned int *)native_pointer(index_vector_obj))[1]);
1791 /*FSHOW((stderr, "/length = %d\n", length));*/
1793 lose("invalid index_vector %x", index_vector_obj);
1799 lispobj next_vector_obj = hash_table[14];
1801 if (is_lisp_pointer(next_vector_obj) &&
1802 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1803 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1804 next_vector = ((unsigned int *)native_pointer(next_vector_obj)) + 2;
1805 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1806 next_vector_length = fixnum_value(((unsigned int *)native_pointer(next_vector_obj))[1]);
1807 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1809 lose("invalid next_vector %x", next_vector_obj);
1813 /* maybe hash vector */
1815 /* FIXME: This bare "15" offset should become a symbolic
1816 * expression of some sort. And all the other bare offsets
1817 * too. And the bare "16" in scavenge(hash_table, 16). And
1818 * probably other stuff too. Ugh.. */
1819 lispobj hash_vector_obj = hash_table[15];
1821 if (is_lisp_pointer(hash_vector_obj) &&
1822 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj))
1823 == SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1824 hash_vector = ((unsigned int *)native_pointer(hash_vector_obj)) + 2;
1825 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1826 gc_assert(fixnum_value(((unsigned int *)native_pointer(hash_vector_obj))[1])
1827 == next_vector_length);
1830 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1834 /* These lengths could be different as the index_vector can be a
1835 * different length from the others, a larger index_vector could help
1836 * reduce collisions. */
1837 gc_assert(next_vector_length*2 == kv_length);
1839 /* now all set up.. */
1841 /* Work through the KV vector. */
1844 for (i = 1; i < next_vector_length; i++) {
1845 lispobj old_key = kv_vector[2*i];
1846 unsigned int old_index = (old_key & 0x1fffffff)%length;
1848 /* Scavenge the key and value. */
1849 scavenge(&kv_vector[2*i],2);
1851 /* Check whether the key has moved and is EQ based. */
1853 lispobj new_key = kv_vector[2*i];
1854 unsigned int new_index = (new_key & 0x1fffffff)%length;
1856 if ((old_index != new_index) &&
1857 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1858 ((new_key != empty_symbol) ||
1859 (kv_vector[2*i] != empty_symbol))) {
1862 "* EQ key %d moved from %x to %x; index %d to %d\n",
1863 i, old_key, new_key, old_index, new_index));*/
1865 if (index_vector[old_index] != 0) {
1866 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1868 /* Unlink the key from the old_index chain. */
1869 if (index_vector[old_index] == i) {
1870 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1871 index_vector[old_index] = next_vector[i];
1872 /* Link it into the needing rehash chain. */
1873 next_vector[i] = fixnum_value(hash_table[11]);
1874 hash_table[11] = make_fixnum(i);
1877 unsigned prior = index_vector[old_index];
1878 unsigned next = next_vector[prior];
1880 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1883 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1886 next_vector[prior] = next_vector[next];
1887 /* Link it into the needing rehash
1890 fixnum_value(hash_table[11]);
1891 hash_table[11] = make_fixnum(next);
1896 next = next_vector[next];
1904 return (CEILING(kv_length + 2, 2));
1913 /* XX This is a hack adapted from cgc.c. These don't work too
1914 * efficiently with the gencgc as a list of the weak pointers is
1915 * maintained within the objects which causes writes to the pages. A
1916 * limited attempt is made to avoid unnecessary writes, but this needs
1918 #define WEAK_POINTER_NWORDS \
1919 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1922 scav_weak_pointer(lispobj *where, lispobj object)
1924 struct weak_pointer *wp = weak_pointers;
1925 /* Push the weak pointer onto the list of weak pointers.
1926 * Do I have to watch for duplicates? Originally this was
1927 * part of trans_weak_pointer but that didn't work in the
1928 * case where the WP was in a promoted region.
1931 /* Check whether it's already in the list. */
1932 while (wp != NULL) {
1933 if (wp == (struct weak_pointer*)where) {
1939 /* Add it to the start of the list. */
1940 wp = (struct weak_pointer*)where;
1941 if (wp->next != weak_pointers) {
1942 wp->next = weak_pointers;
1944 /*SHOW("avoided write to weak pointer");*/
1949 /* Do not let GC scavenge the value slot of the weak pointer.
1950 * (That is why it is a weak pointer.) */
1952 return WEAK_POINTER_NWORDS;
1957 search_read_only_space(void *pointer)
1959 lispobj *start = (lispobj *) READ_ONLY_SPACE_START;
1960 lispobj *end = (lispobj *) SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1961 if ((pointer < (void *)start) || (pointer >= (void *)end))
1963 return (search_space(start,
1964 (((lispobj *)pointer)+2)-start,
1965 (lispobj *) pointer));
1969 search_static_space(void *pointer)
1971 lispobj *start = (lispobj *)STATIC_SPACE_START;
1972 lispobj *end = (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1973 if ((pointer < (void *)start) || (pointer >= (void *)end))
1975 return (search_space(start,
1976 (((lispobj *)pointer)+2)-start,
1977 (lispobj *) pointer));
1980 /* a faster version for searching the dynamic space. This will work even
1981 * if the object is in a current allocation region. */
1983 search_dynamic_space(void *pointer)
1985 int page_index = find_page_index(pointer);
1988 /* The address may be invalid, so do some checks. */
1989 if ((page_index == -1) ||
1990 (page_table[page_index].allocated == FREE_PAGE_FLAG))
1992 start = (lispobj *)((void *)page_address(page_index)
1993 + page_table[page_index].first_object_offset);
1994 return (search_space(start,
1995 (((lispobj *)pointer)+2)-start,
1996 (lispobj *)pointer));
1999 /* Is there any possibility that pointer is a valid Lisp object
2000 * reference, and/or something else (e.g. subroutine call return
2001 * address) which should prevent us from moving the referred-to thing?
2002 * This is called from preserve_pointers() */
2004 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2006 lispobj *start_addr;
2008 /* Find the object start address. */
2009 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2013 /* We need to allow raw pointers into Code objects for return
2014 * addresses. This will also pick up pointers to functions in code
2016 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2017 /* XXX could do some further checks here */
2021 /* If it's not a return address then it needs to be a valid Lisp
2023 if (!is_lisp_pointer((lispobj)pointer)) {
2027 /* Check that the object pointed to is consistent with the pointer
2030 switch (lowtag_of((lispobj)pointer)) {
2031 case FUN_POINTER_LOWTAG:
2032 /* Start_addr should be the enclosing code object, or a closure
2034 switch (widetag_of(*start_addr)) {
2035 case CODE_HEADER_WIDETAG:
2036 /* This case is probably caught above. */
2038 case CLOSURE_HEADER_WIDETAG:
2039 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2040 if ((unsigned)pointer !=
2041 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2045 pointer, start_addr, *start_addr));
2053 pointer, start_addr, *start_addr));
2057 case LIST_POINTER_LOWTAG:
2058 if ((unsigned)pointer !=
2059 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2063 pointer, start_addr, *start_addr));
2066 /* Is it plausible cons? */
2067 if ((is_lisp_pointer(start_addr[0])
2068 || ((start_addr[0] & 3) == 0) /* fixnum */
2069 || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
2070 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2071 && (is_lisp_pointer(start_addr[1])
2072 || ((start_addr[1] & 3) == 0) /* fixnum */
2073 || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
2074 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2080 pointer, start_addr, *start_addr));
2083 case INSTANCE_POINTER_LOWTAG:
2084 if ((unsigned)pointer !=
2085 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2089 pointer, start_addr, *start_addr));
2092 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2096 pointer, start_addr, *start_addr));
2100 case OTHER_POINTER_LOWTAG:
2101 if ((unsigned)pointer !=
2102 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2106 pointer, start_addr, *start_addr));
2109 /* Is it plausible? Not a cons. XXX should check the headers. */
2110 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2114 pointer, start_addr, *start_addr));
2117 switch (widetag_of(start_addr[0])) {
2118 case UNBOUND_MARKER_WIDETAG:
2119 case BASE_CHAR_WIDETAG:
2123 pointer, start_addr, *start_addr));
2126 /* only pointed to by function pointers? */
2127 case CLOSURE_HEADER_WIDETAG:
2128 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2132 pointer, start_addr, *start_addr));
2135 case INSTANCE_HEADER_WIDETAG:
2139 pointer, start_addr, *start_addr));
2142 /* the valid other immediate pointer objects */
2143 case SIMPLE_VECTOR_WIDETAG:
2145 case COMPLEX_WIDETAG:
2146 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2147 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2149 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2150 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2152 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2153 case COMPLEX_LONG_FLOAT_WIDETAG:
2155 case SIMPLE_ARRAY_WIDETAG:
2156 case COMPLEX_BASE_STRING_WIDETAG:
2157 case COMPLEX_VECTOR_NIL_WIDETAG:
2158 case COMPLEX_BIT_VECTOR_WIDETAG:
2159 case COMPLEX_VECTOR_WIDETAG:
2160 case COMPLEX_ARRAY_WIDETAG:
2161 case VALUE_CELL_HEADER_WIDETAG:
2162 case SYMBOL_HEADER_WIDETAG:
2164 case CODE_HEADER_WIDETAG:
2165 case BIGNUM_WIDETAG:
2166 case SINGLE_FLOAT_WIDETAG:
2167 case DOUBLE_FLOAT_WIDETAG:
2168 #ifdef LONG_FLOAT_WIDETAG
2169 case LONG_FLOAT_WIDETAG:
2171 case SIMPLE_BASE_STRING_WIDETAG:
2172 case SIMPLE_BIT_VECTOR_WIDETAG:
2173 case SIMPLE_ARRAY_NIL_WIDETAG:
2174 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2175 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2176 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2177 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2178 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2179 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2180 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2181 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2182 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2183 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2184 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2186 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2187 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2189 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2190 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2192 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2193 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2195 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2196 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2197 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2198 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2200 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2201 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2203 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2204 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2206 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2207 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2210 case WEAK_POINTER_WIDETAG:
2217 pointer, start_addr, *start_addr));
2225 pointer, start_addr, *start_addr));
2233 /* Adjust large bignum and vector objects. This will adjust the
2234 * allocated region if the size has shrunk, and move unboxed objects
2235 * into unboxed pages. The pages are not promoted here, and the
2236 * promoted region is not added to the new_regions; this is really
2237 * only designed to be called from preserve_pointer(). Shouldn't fail
2238 * if this is missed, just may delay the moving of objects to unboxed
2239 * pages, and the freeing of pages. */
2241 maybe_adjust_large_object(lispobj *where)
2246 int remaining_bytes;
2253 /* Check whether it's a vector or bignum object. */
2254 switch (widetag_of(where[0])) {
2255 case SIMPLE_VECTOR_WIDETAG:
2256 boxed = BOXED_PAGE_FLAG;
2258 case BIGNUM_WIDETAG:
2259 case SIMPLE_BASE_STRING_WIDETAG:
2260 case SIMPLE_BIT_VECTOR_WIDETAG:
2261 case SIMPLE_ARRAY_NIL_WIDETAG:
2262 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2263 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2264 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2265 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2266 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2267 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2268 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2269 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2270 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2271 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2272 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2274 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2275 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2277 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2278 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2280 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2281 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2283 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2284 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2285 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2286 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2288 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2289 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2291 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2292 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2294 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2295 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2297 boxed = UNBOXED_PAGE_FLAG;
2303 /* Find its current size. */
2304 nwords = (sizetab[widetag_of(where[0])])(where);
2306 first_page = find_page_index((void *)where);
2307 gc_assert(first_page >= 0);
2309 /* Note: Any page write-protection must be removed, else a later
2310 * scavenge_newspace may incorrectly not scavenge these pages.
2311 * This would not be necessary if they are added to the new areas,
2312 * but lets do it for them all (they'll probably be written
2315 gc_assert(page_table[first_page].first_object_offset == 0);
2317 next_page = first_page;
2318 remaining_bytes = nwords*4;
2319 while (remaining_bytes > PAGE_BYTES) {
2320 gc_assert(page_table[next_page].gen == from_space);
2321 gc_assert((page_table[next_page].allocated == BOXED_PAGE_FLAG)
2322 || (page_table[next_page].allocated == UNBOXED_PAGE_FLAG));
2323 gc_assert(page_table[next_page].large_object);
2324 gc_assert(page_table[next_page].first_object_offset ==
2325 -PAGE_BYTES*(next_page-first_page));
2326 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2328 page_table[next_page].allocated = boxed;
2330 /* Shouldn't be write-protected at this stage. Essential that the
2332 gc_assert(!page_table[next_page].write_protected);
2333 remaining_bytes -= PAGE_BYTES;
2337 /* Now only one page remains, but the object may have shrunk so
2338 * there may be more unused pages which will be freed. */
2340 /* Object may have shrunk but shouldn't have grown - check. */
2341 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2343 page_table[next_page].allocated = boxed;
2344 gc_assert(page_table[next_page].allocated ==
2345 page_table[first_page].allocated);
2347 /* Adjust the bytes_used. */
2348 old_bytes_used = page_table[next_page].bytes_used;
2349 page_table[next_page].bytes_used = remaining_bytes;
2351 bytes_freed = old_bytes_used - remaining_bytes;
2353 /* Free any remaining pages; needs care. */
2355 while ((old_bytes_used == PAGE_BYTES) &&
2356 (page_table[next_page].gen == from_space) &&
2357 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
2358 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
2359 page_table[next_page].large_object &&
2360 (page_table[next_page].first_object_offset ==
2361 -(next_page - first_page)*PAGE_BYTES)) {
2362 /* It checks out OK, free the page. We don't need to both zeroing
2363 * pages as this should have been done before shrinking the
2364 * object. These pages shouldn't be write protected as they
2365 * should be zero filled. */
2366 gc_assert(page_table[next_page].write_protected == 0);
2368 old_bytes_used = page_table[next_page].bytes_used;
2369 page_table[next_page].allocated = FREE_PAGE_FLAG;
2370 page_table[next_page].bytes_used = 0;
2371 bytes_freed += old_bytes_used;
2375 if ((bytes_freed > 0) && gencgc_verbose) {
2377 "/maybe_adjust_large_object() freed %d\n",
2381 generations[from_space].bytes_allocated -= bytes_freed;
2382 bytes_allocated -= bytes_freed;
2387 /* Take a possible pointer to a Lisp object and mark its page in the
2388 * page_table so that it will not be relocated during a GC.
2390 * This involves locating the page it points to, then backing up to
2391 * the start of its region, then marking all pages dont_move from there
2392 * up to the first page that's not full or has a different generation
2394 * It is assumed that all the page static flags have been cleared at
2395 * the start of a GC.
2397 * It is also assumed that the current gc_alloc() region has been
2398 * flushed and the tables updated. */
2400 preserve_pointer(void *addr)
2402 int addr_page_index = find_page_index(addr);
2405 unsigned region_allocation;
2407 /* quick check 1: Address is quite likely to have been invalid. */
2408 if ((addr_page_index == -1)
2409 || (page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2410 || (page_table[addr_page_index].bytes_used == 0)
2411 || (page_table[addr_page_index].gen != from_space)
2412 /* Skip if already marked dont_move. */
2413 || (page_table[addr_page_index].dont_move != 0))
2415 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2416 /* (Now that we know that addr_page_index is in range, it's
2417 * safe to index into page_table[] with it.) */
2418 region_allocation = page_table[addr_page_index].allocated;
2420 /* quick check 2: Check the offset within the page.
2423 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2426 /* Filter out anything which can't be a pointer to a Lisp object
2427 * (or, as a special case which also requires dont_move, a return
2428 * address referring to something in a CodeObject). This is
2429 * expensive but important, since it vastly reduces the
2430 * probability that random garbage will be bogusly interpreted as
2431 * a pointer which prevents a page from moving. */
2432 if (!(possibly_valid_dynamic_space_pointer(addr)))
2435 /* Find the beginning of the region. Note that there may be
2436 * objects in the region preceding the one that we were passed a
2437 * pointer to: if this is the case, we will write-protect all the
2438 * previous objects' pages too. */
2441 /* I think this'd work just as well, but without the assertions.
2442 * -dan 2004.01.01 */
2444 find_page_index(page_address(addr_page_index)+
2445 page_table[addr_page_index].first_object_offset);
2447 first_page = addr_page_index;
2448 while (page_table[first_page].first_object_offset != 0) {
2450 /* Do some checks. */
2451 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2452 gc_assert(page_table[first_page].gen == from_space);
2453 gc_assert(page_table[first_page].allocated == region_allocation);
2457 /* Adjust any large objects before promotion as they won't be
2458 * copied after promotion. */
2459 if (page_table[first_page].large_object) {
2460 maybe_adjust_large_object(page_address(first_page));
2461 /* If a large object has shrunk then addr may now point to a
2462 * free area in which case it's ignored here. Note it gets
2463 * through the valid pointer test above because the tail looks
2465 if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2466 || (page_table[addr_page_index].bytes_used == 0)
2467 /* Check the offset within the page. */
2468 || (((unsigned)addr & (PAGE_BYTES - 1))
2469 > page_table[addr_page_index].bytes_used)) {
2471 "weird? ignore ptr 0x%x to freed area of large object\n",
2475 /* It may have moved to unboxed pages. */
2476 region_allocation = page_table[first_page].allocated;
2479 /* Now work forward until the end of this contiguous area is found,
2480 * marking all pages as dont_move. */
2481 for (i = first_page; ;i++) {
2482 gc_assert(page_table[i].allocated == region_allocation);
2484 /* Mark the page static. */
2485 page_table[i].dont_move = 1;
2487 /* Move the page to the new_space. XX I'd rather not do this
2488 * but the GC logic is not quite able to copy with the static
2489 * pages remaining in the from space. This also requires the
2490 * generation bytes_allocated counters be updated. */
2491 page_table[i].gen = new_space;
2492 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2493 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2495 /* It is essential that the pages are not write protected as
2496 * they may have pointers into the old-space which need
2497 * scavenging. They shouldn't be write protected at this
2499 gc_assert(!page_table[i].write_protected);
2501 /* Check whether this is the last page in this contiguous block.. */
2502 if ((page_table[i].bytes_used < PAGE_BYTES)
2503 /* ..or it is PAGE_BYTES and is the last in the block */
2504 || (page_table[i+1].allocated == FREE_PAGE_FLAG)
2505 || (page_table[i+1].bytes_used == 0) /* next page free */
2506 || (page_table[i+1].gen != from_space) /* diff. gen */
2507 || (page_table[i+1].first_object_offset == 0))
2511 /* Check that the page is now static. */
2512 gc_assert(page_table[addr_page_index].dont_move != 0);
2515 /* If the given page is not write-protected, then scan it for pointers
2516 * to younger generations or the top temp. generation, if no
2517 * suspicious pointers are found then the page is write-protected.
2519 * Care is taken to check for pointers to the current gc_alloc()
2520 * region if it is a younger generation or the temp. generation. This
2521 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2522 * the gc_alloc_generation does not need to be checked as this is only
2523 * called from scavenge_generation() when the gc_alloc generation is
2524 * younger, so it just checks if there is a pointer to the current
2527 * We return 1 if the page was write-protected, else 0. */
2529 update_page_write_prot(int page)
2531 int gen = page_table[page].gen;
2534 void **page_addr = (void **)page_address(page);
2535 int num_words = page_table[page].bytes_used / 4;
2537 /* Shouldn't be a free page. */
2538 gc_assert(page_table[page].allocated != FREE_PAGE_FLAG);
2539 gc_assert(page_table[page].bytes_used != 0);
2541 /* Skip if it's already write-protected, pinned, or unboxed */
2542 if (page_table[page].write_protected
2543 || page_table[page].dont_move
2544 || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
2547 /* Scan the page for pointers to younger generations or the
2548 * top temp. generation. */
2550 for (j = 0; j < num_words; j++) {
2551 void *ptr = *(page_addr+j);
2552 int index = find_page_index(ptr);
2554 /* Check that it's in the dynamic space */
2556 if (/* Does it point to a younger or the temp. generation? */
2557 ((page_table[index].allocated != FREE_PAGE_FLAG)
2558 && (page_table[index].bytes_used != 0)
2559 && ((page_table[index].gen < gen)
2560 || (page_table[index].gen == NUM_GENERATIONS)))
2562 /* Or does it point within a current gc_alloc() region? */
2563 || ((boxed_region.start_addr <= ptr)
2564 && (ptr <= boxed_region.free_pointer))
2565 || ((unboxed_region.start_addr <= ptr)
2566 && (ptr <= unboxed_region.free_pointer))) {
2573 /* Write-protect the page. */
2574 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2576 os_protect((void *)page_addr,
2578 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2580 /* Note the page as protected in the page tables. */
2581 page_table[page].write_protected = 1;
2587 /* Scavenge a generation.
2589 * This will not resolve all pointers when generation is the new
2590 * space, as new objects may be added which are not checked here - use
2591 * scavenge_newspace generation.
2593 * Write-protected pages should not have any pointers to the
2594 * from_space so do need scavenging; thus write-protected pages are
2595 * not always scavenged. There is some code to check that these pages
2596 * are not written; but to check fully the write-protected pages need
2597 * to be scavenged by disabling the code to skip them.
2599 * Under the current scheme when a generation is GCed the younger
2600 * generations will be empty. So, when a generation is being GCed it
2601 * is only necessary to scavenge the older generations for pointers
2602 * not the younger. So a page that does not have pointers to younger
2603 * generations does not need to be scavenged.
2605 * The write-protection can be used to note pages that don't have
2606 * pointers to younger pages. But pages can be written without having
2607 * pointers to younger generations. After the pages are scavenged here
2608 * they can be scanned for pointers to younger generations and if
2609 * there are none the page can be write-protected.
2611 * One complication is when the newspace is the top temp. generation.
2613 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2614 * that none were written, which they shouldn't be as they should have
2615 * no pointers to younger generations. This breaks down for weak
2616 * pointers as the objects contain a link to the next and are written
2617 * if a weak pointer is scavenged. Still it's a useful check. */
2619 scavenge_generation(int generation)
2626 /* Clear the write_protected_cleared flags on all pages. */
2627 for (i = 0; i < NUM_PAGES; i++)
2628 page_table[i].write_protected_cleared = 0;
2631 for (i = 0; i < last_free_page; i++) {
2632 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2633 && (page_table[i].bytes_used != 0)
2634 && (page_table[i].gen == generation)) {
2636 int write_protected=1;
2638 /* This should be the start of a region */
2639 gc_assert(page_table[i].first_object_offset == 0);
2641 /* Now work forward until the end of the region */
2642 for (last_page = i; ; last_page++) {
2644 write_protected && page_table[last_page].write_protected;
2645 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2646 /* Or it is PAGE_BYTES and is the last in the block */
2647 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2648 || (page_table[last_page+1].bytes_used == 0)
2649 || (page_table[last_page+1].gen != generation)
2650 || (page_table[last_page+1].first_object_offset == 0))
2653 if (!write_protected) {
2654 scavenge(page_address(i), (page_table[last_page].bytes_used
2655 + (last_page-i)*PAGE_BYTES)/4);
2657 /* Now scan the pages and write protect those that
2658 * don't have pointers to younger generations. */
2659 if (enable_page_protection) {
2660 for (j = i; j <= last_page; j++) {
2661 num_wp += update_page_write_prot(j);
2668 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2670 "/write protected %d pages within generation %d\n",
2671 num_wp, generation));
2675 /* Check that none of the write_protected pages in this generation
2676 * have been written to. */
2677 for (i = 0; i < NUM_PAGES; i++) {
2678 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2679 && (page_table[i].bytes_used != 0)
2680 && (page_table[i].gen == generation)
2681 && (page_table[i].write_protected_cleared != 0)) {
2682 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2684 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2685 page_table[i].bytes_used,
2686 page_table[i].first_object_offset,
2687 page_table[i].dont_move));
2688 lose("write to protected page %d in scavenge_generation()", i);
2695 /* Scavenge a newspace generation. As it is scavenged new objects may
2696 * be allocated to it; these will also need to be scavenged. This
2697 * repeats until there are no more objects unscavenged in the
2698 * newspace generation.
2700 * To help improve the efficiency, areas written are recorded by
2701 * gc_alloc() and only these scavenged. Sometimes a little more will be
2702 * scavenged, but this causes no harm. An easy check is done that the
2703 * scavenged bytes equals the number allocated in the previous
2706 * Write-protected pages are not scanned except if they are marked
2707 * dont_move in which case they may have been promoted and still have
2708 * pointers to the from space.
2710 * Write-protected pages could potentially be written by alloc however
2711 * to avoid having to handle re-scavenging of write-protected pages
2712 * gc_alloc() does not write to write-protected pages.
2714 * New areas of objects allocated are recorded alternatively in the two
2715 * new_areas arrays below. */
2716 static struct new_area new_areas_1[NUM_NEW_AREAS];
2717 static struct new_area new_areas_2[NUM_NEW_AREAS];
2719 /* Do one full scan of the new space generation. This is not enough to
2720 * complete the job as new objects may be added to the generation in
2721 * the process which are not scavenged. */
2723 scavenge_newspace_generation_one_scan(int generation)
2728 "/starting one full scan of newspace generation %d\n",
2730 for (i = 0; i < last_free_page; i++) {
2731 /* Note that this skips over open regions when it encounters them. */
2732 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2733 && (page_table[i].bytes_used != 0)
2734 && (page_table[i].gen == generation)
2735 && ((page_table[i].write_protected == 0)
2736 /* (This may be redundant as write_protected is now
2737 * cleared before promotion.) */
2738 || (page_table[i].dont_move == 1))) {
2742 /* The scavenge will start at the first_object_offset of page i.
2744 * We need to find the full extent of this contiguous
2745 * block in case objects span pages.
2747 * Now work forward until the end of this contiguous area
2748 * is found. A small area is preferred as there is a
2749 * better chance of its pages being write-protected. */
2750 for (last_page = i; ;last_page++) {
2751 /* If all pages are write-protected and movable,
2752 * then no need to scavenge */
2753 all_wp=all_wp && page_table[last_page].write_protected &&
2754 !page_table[last_page].dont_move;
2756 /* Check whether this is the last page in this
2757 * contiguous block */
2758 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2759 /* Or it is PAGE_BYTES and is the last in the block */
2760 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2761 || (page_table[last_page+1].bytes_used == 0)
2762 || (page_table[last_page+1].gen != generation)
2763 || (page_table[last_page+1].first_object_offset == 0))
2767 /* Do a limited check for write-protected pages. */
2771 size = (page_table[last_page].bytes_used
2772 + (last_page-i)*PAGE_BYTES
2773 - page_table[i].first_object_offset)/4;
2774 new_areas_ignore_page = last_page;
2776 scavenge(page_address(i) +
2777 page_table[i].first_object_offset,
2785 "/done with one full scan of newspace generation %d\n",
2789 /* Do a complete scavenge of the newspace generation. */
2791 scavenge_newspace_generation(int generation)
2795 /* the new_areas array currently being written to by gc_alloc() */
2796 struct new_area (*current_new_areas)[] = &new_areas_1;
2797 int current_new_areas_index;
2799 /* the new_areas created by the previous scavenge cycle */
2800 struct new_area (*previous_new_areas)[] = NULL;
2801 int previous_new_areas_index;
2803 /* Flush the current regions updating the tables. */
2804 gc_alloc_update_all_page_tables();
2806 /* Turn on the recording of new areas by gc_alloc(). */
2807 new_areas = current_new_areas;
2808 new_areas_index = 0;
2810 /* Don't need to record new areas that get scavenged anyway during
2811 * scavenge_newspace_generation_one_scan. */
2812 record_new_objects = 1;
2814 /* Start with a full scavenge. */
2815 scavenge_newspace_generation_one_scan(generation);
2817 /* Record all new areas now. */
2818 record_new_objects = 2;
2820 /* Flush the current regions updating the tables. */
2821 gc_alloc_update_all_page_tables();
2823 /* Grab new_areas_index. */
2824 current_new_areas_index = new_areas_index;
2827 "The first scan is finished; current_new_areas_index=%d.\n",
2828 current_new_areas_index));*/
2830 while (current_new_areas_index > 0) {
2831 /* Move the current to the previous new areas */
2832 previous_new_areas = current_new_areas;
2833 previous_new_areas_index = current_new_areas_index;
2835 /* Scavenge all the areas in previous new areas. Any new areas
2836 * allocated are saved in current_new_areas. */
2838 /* Allocate an array for current_new_areas; alternating between
2839 * new_areas_1 and 2 */
2840 if (previous_new_areas == &new_areas_1)
2841 current_new_areas = &new_areas_2;
2843 current_new_areas = &new_areas_1;
2845 /* Set up for gc_alloc(). */
2846 new_areas = current_new_areas;
2847 new_areas_index = 0;
2849 /* Check whether previous_new_areas had overflowed. */
2850 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2852 /* New areas of objects allocated have been lost so need to do a
2853 * full scan to be sure! If this becomes a problem try
2854 * increasing NUM_NEW_AREAS. */
2856 SHOW("new_areas overflow, doing full scavenge");
2858 /* Don't need to record new areas that get scavenge anyway
2859 * during scavenge_newspace_generation_one_scan. */
2860 record_new_objects = 1;
2862 scavenge_newspace_generation_one_scan(generation);
2864 /* Record all new areas now. */
2865 record_new_objects = 2;
2867 /* Flush the current regions updating the tables. */
2868 gc_alloc_update_all_page_tables();
2872 /* Work through previous_new_areas. */
2873 for (i = 0; i < previous_new_areas_index; i++) {
2874 /* FIXME: All these bare *4 and /4 should be something
2875 * like BYTES_PER_WORD or WBYTES. */
2876 int page = (*previous_new_areas)[i].page;
2877 int offset = (*previous_new_areas)[i].offset;
2878 int size = (*previous_new_areas)[i].size / 4;
2879 gc_assert((*previous_new_areas)[i].size % 4 == 0);
2880 scavenge(page_address(page)+offset, size);
2883 /* Flush the current regions updating the tables. */
2884 gc_alloc_update_all_page_tables();
2887 current_new_areas_index = new_areas_index;
2890 "The re-scan has finished; current_new_areas_index=%d.\n",
2891 current_new_areas_index));*/
2894 /* Turn off recording of areas allocated by gc_alloc(). */
2895 record_new_objects = 0;
2898 /* Check that none of the write_protected pages in this generation
2899 * have been written to. */
2900 for (i = 0; i < NUM_PAGES; i++) {
2901 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2902 && (page_table[i].bytes_used != 0)
2903 && (page_table[i].gen == generation)
2904 && (page_table[i].write_protected_cleared != 0)
2905 && (page_table[i].dont_move == 0)) {
2906 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2907 i, generation, page_table[i].dont_move);
2913 /* Un-write-protect all the pages in from_space. This is done at the
2914 * start of a GC else there may be many page faults while scavenging
2915 * the newspace (I've seen drive the system time to 99%). These pages
2916 * would need to be unprotected anyway before unmapping in
2917 * free_oldspace; not sure what effect this has on paging.. */
2919 unprotect_oldspace(void)
2923 for (i = 0; i < last_free_page; i++) {
2924 if ((page_table[i].allocated != FREE_PAGE_FLAG)
2925 && (page_table[i].bytes_used != 0)
2926 && (page_table[i].gen == from_space)) {
2929 page_start = (void *)page_address(i);
2931 /* Remove any write-protection. We should be able to rely
2932 * on the write-protect flag to avoid redundant calls. */
2933 if (page_table[i].write_protected) {
2934 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2935 page_table[i].write_protected = 0;
2941 /* Work through all the pages and free any in from_space. This
2942 * assumes that all objects have been copied or promoted to an older
2943 * generation. Bytes_allocated and the generation bytes_allocated
2944 * counter are updated. The number of bytes freed is returned. */
2948 int bytes_freed = 0;
2949 int first_page, last_page;
2954 /* Find a first page for the next region of pages. */
2955 while ((first_page < last_free_page)
2956 && ((page_table[first_page].allocated == FREE_PAGE_FLAG)
2957 || (page_table[first_page].bytes_used == 0)
2958 || (page_table[first_page].gen != from_space)))
2961 if (first_page >= last_free_page)
2964 /* Find the last page of this region. */
2965 last_page = first_page;
2968 /* Free the page. */
2969 bytes_freed += page_table[last_page].bytes_used;
2970 generations[page_table[last_page].gen].bytes_allocated -=
2971 page_table[last_page].bytes_used;
2972 page_table[last_page].allocated = FREE_PAGE_FLAG;
2973 page_table[last_page].bytes_used = 0;
2975 /* Remove any write-protection. We should be able to rely
2976 * on the write-protect flag to avoid redundant calls. */
2978 void *page_start = (void *)page_address(last_page);
2980 if (page_table[last_page].write_protected) {
2981 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2982 page_table[last_page].write_protected = 0;
2987 while ((last_page < last_free_page)
2988 && (page_table[last_page].allocated != FREE_PAGE_FLAG)
2989 && (page_table[last_page].bytes_used != 0)
2990 && (page_table[last_page].gen == from_space));
2992 /* Zero pages from first_page to (last_page-1).
2994 * FIXME: Why not use os_zero(..) function instead of
2995 * hand-coding this again? (Check other gencgc_unmap_zero
2997 if (gencgc_unmap_zero) {
2998 void *page_start, *addr;
3000 page_start = (void *)page_address(first_page);
3002 os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
3003 addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
3004 if (addr == NULL || addr != page_start) {
3005 lose("free_oldspace: page moved, 0x%08x ==> 0x%08x",page_start,
3011 page_start = (int *)page_address(first_page);
3012 memset(page_start, 0,PAGE_BYTES*(last_page-first_page));
3015 first_page = last_page;
3017 } while (first_page < last_free_page);
3019 bytes_allocated -= bytes_freed;
3024 /* Print some information about a pointer at the given address. */
3026 print_ptr(lispobj *addr)
3028 /* If addr is in the dynamic space then out the page information. */
3029 int pi1 = find_page_index((void*)addr);
3032 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3033 (unsigned int) addr,
3035 page_table[pi1].allocated,
3036 page_table[pi1].gen,
3037 page_table[pi1].bytes_used,
3038 page_table[pi1].first_object_offset,
3039 page_table[pi1].dont_move);
3040 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3053 extern int undefined_tramp;
3056 verify_space(lispobj *start, size_t words)
3058 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3059 int is_in_readonly_space =
3060 (READ_ONLY_SPACE_START <= (unsigned)start &&
3061 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3065 lispobj thing = *(lispobj*)start;
3067 if (is_lisp_pointer(thing)) {
3068 int page_index = find_page_index((void*)thing);
3069 int to_readonly_space =
3070 (READ_ONLY_SPACE_START <= thing &&
3071 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3072 int to_static_space =
3073 (STATIC_SPACE_START <= thing &&
3074 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3076 /* Does it point to the dynamic space? */
3077 if (page_index != -1) {
3078 /* If it's within the dynamic space it should point to a used
3079 * page. XX Could check the offset too. */
3080 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
3081 && (page_table[page_index].bytes_used == 0))
3082 lose ("Ptr %x @ %x sees free page.", thing, start);
3083 /* Check that it doesn't point to a forwarding pointer! */
3084 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3085 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3087 /* Check that its not in the RO space as it would then be a
3088 * pointer from the RO to the dynamic space. */
3089 if (is_in_readonly_space) {
3090 lose("ptr to dynamic space %x from RO space %x",
3093 /* Does it point to a plausible object? This check slows
3094 * it down a lot (so it's commented out).
3096 * "a lot" is serious: it ate 50 minutes cpu time on
3097 * my duron 950 before I came back from lunch and
3100 * FIXME: Add a variable to enable this
3103 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3104 lose("ptr %x to invalid object %x", thing, start);
3108 /* Verify that it points to another valid space. */
3109 if (!to_readonly_space && !to_static_space
3110 && (thing != (unsigned)&undefined_tramp)) {
3111 lose("Ptr %x @ %x sees junk.", thing, start);
3115 if (!(fixnump(thing))) {
3117 switch(widetag_of(*start)) {
3120 case SIMPLE_VECTOR_WIDETAG:
3122 case COMPLEX_WIDETAG:
3123 case SIMPLE_ARRAY_WIDETAG:
3124 case COMPLEX_BASE_STRING_WIDETAG:
3125 case COMPLEX_VECTOR_NIL_WIDETAG:
3126 case COMPLEX_BIT_VECTOR_WIDETAG:
3127 case COMPLEX_VECTOR_WIDETAG:
3128 case COMPLEX_ARRAY_WIDETAG:
3129 case CLOSURE_HEADER_WIDETAG:
3130 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3131 case VALUE_CELL_HEADER_WIDETAG:
3132 case SYMBOL_HEADER_WIDETAG:
3133 case BASE_CHAR_WIDETAG:
3134 case UNBOUND_MARKER_WIDETAG:
3135 case INSTANCE_HEADER_WIDETAG:
3140 case CODE_HEADER_WIDETAG:
3142 lispobj object = *start;
3144 int nheader_words, ncode_words, nwords;
3146 struct simple_fun *fheaderp;
3148 code = (struct code *) start;
3150 /* Check that it's not in the dynamic space.
3151 * FIXME: Isn't is supposed to be OK for code
3152 * objects to be in the dynamic space these days? */
3153 if (is_in_dynamic_space
3154 /* It's ok if it's byte compiled code. The trace
3155 * table offset will be a fixnum if it's x86
3156 * compiled code - check.
3158 * FIXME: #^#@@! lack of abstraction here..
3159 * This line can probably go away now that
3160 * there's no byte compiler, but I've got
3161 * too much to worry about right now to try
3162 * to make sure. -- WHN 2001-10-06 */
3163 && fixnump(code->trace_table_offset)
3164 /* Only when enabled */
3165 && verify_dynamic_code_check) {
3167 "/code object at %x in the dynamic space\n",
3171 ncode_words = fixnum_value(code->code_size);
3172 nheader_words = HeaderValue(object);
3173 nwords = ncode_words + nheader_words;
3174 nwords = CEILING(nwords, 2);
3175 /* Scavenge the boxed section of the code data block */
3176 verify_space(start + 1, nheader_words - 1);
3178 /* Scavenge the boxed section of each function
3179 * object in the code data block. */
3180 fheaderl = code->entry_points;
3181 while (fheaderl != NIL) {
3183 (struct simple_fun *) native_pointer(fheaderl);
3184 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3185 verify_space(&fheaderp->name, 1);
3186 verify_space(&fheaderp->arglist, 1);
3187 verify_space(&fheaderp->type, 1);
3188 fheaderl = fheaderp->next;
3194 /* unboxed objects */
3195 case BIGNUM_WIDETAG:
3196 case SINGLE_FLOAT_WIDETAG:
3197 case DOUBLE_FLOAT_WIDETAG:
3198 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3199 case LONG_FLOAT_WIDETAG:
3201 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3202 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3204 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3205 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3207 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3208 case COMPLEX_LONG_FLOAT_WIDETAG:
3210 case SIMPLE_BASE_STRING_WIDETAG:
3211 case SIMPLE_BIT_VECTOR_WIDETAG:
3212 case SIMPLE_ARRAY_NIL_WIDETAG:
3213 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3214 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3215 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3216 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3217 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3218 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3219 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3220 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3221 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3222 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3223 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3225 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3226 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3228 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3229 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3231 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3232 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3234 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3235 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3236 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3237 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3239 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3240 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3242 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3243 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3245 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3246 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3249 case WEAK_POINTER_WIDETAG:
3250 count = (sizetab[widetag_of(*start)])(start);
3266 /* FIXME: It would be nice to make names consistent so that
3267 * foo_size meant size *in* *bytes* instead of size in some
3268 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3269 * Some counts of lispobjs are called foo_count; it might be good
3270 * to grep for all foo_size and rename the appropriate ones to
3272 int read_only_space_size =
3273 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3274 - (lispobj*)READ_ONLY_SPACE_START;
3275 int static_space_size =
3276 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3277 - (lispobj*)STATIC_SPACE_START;
3279 for_each_thread(th) {
3280 int binding_stack_size =
3281 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3282 - (lispobj*)th->binding_stack_start;
3283 verify_space(th->binding_stack_start, binding_stack_size);
3285 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3286 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3290 verify_generation(int generation)
3294 for (i = 0; i < last_free_page; i++) {
3295 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3296 && (page_table[i].bytes_used != 0)
3297 && (page_table[i].gen == generation)) {
3299 int region_allocation = page_table[i].allocated;
3301 /* This should be the start of a contiguous block */
3302 gc_assert(page_table[i].first_object_offset == 0);
3304 /* Need to find the full extent of this contiguous block in case
3305 objects span pages. */
3307 /* Now work forward until the end of this contiguous area is
3309 for (last_page = i; ;last_page++)
3310 /* Check whether this is the last page in this contiguous
3312 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3313 /* Or it is PAGE_BYTES and is the last in the block */
3314 || (page_table[last_page+1].allocated != region_allocation)
3315 || (page_table[last_page+1].bytes_used == 0)
3316 || (page_table[last_page+1].gen != generation)
3317 || (page_table[last_page+1].first_object_offset == 0))
3320 verify_space(page_address(i), (page_table[last_page].bytes_used
3321 + (last_page-i)*PAGE_BYTES)/4);
3327 /* Check that all the free space is zero filled. */
3329 verify_zero_fill(void)
3333 for (page = 0; page < last_free_page; page++) {
3334 if (page_table[page].allocated == FREE_PAGE_FLAG) {
3335 /* The whole page should be zero filled. */
3336 int *start_addr = (int *)page_address(page);
3339 for (i = 0; i < size; i++) {
3340 if (start_addr[i] != 0) {
3341 lose("free page not zero at %x", start_addr + i);
3345 int free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3346 if (free_bytes > 0) {
3347 int *start_addr = (int *)((unsigned)page_address(page)
3348 + page_table[page].bytes_used);
3349 int size = free_bytes / 4;
3351 for (i = 0; i < size; i++) {
3352 if (start_addr[i] != 0) {
3353 lose("free region not zero at %x", start_addr + i);
3361 /* External entry point for verify_zero_fill */
3363 gencgc_verify_zero_fill(void)
3365 /* Flush the alloc regions updating the tables. */
3366 gc_alloc_update_all_page_tables();
3367 SHOW("verifying zero fill");
3372 verify_dynamic_space(void)
3376 for (i = 0; i < NUM_GENERATIONS; i++)
3377 verify_generation(i);
3379 if (gencgc_enable_verify_zero_fill)
3383 /* Write-protect all the dynamic boxed pages in the given generation. */
3385 write_protect_generation_pages(int generation)
3389 gc_assert(generation < NUM_GENERATIONS);
3391 for (i = 0; i < last_free_page; i++)
3392 if ((page_table[i].allocated == BOXED_PAGE_FLAG)
3393 && (page_table[i].bytes_used != 0)
3394 && !page_table[i].dont_move
3395 && (page_table[i].gen == generation)) {
3398 page_start = (void *)page_address(i);
3400 os_protect(page_start,
3402 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3404 /* Note the page as protected in the page tables. */
3405 page_table[i].write_protected = 1;
3408 if (gencgc_verbose > 1) {
3410 "/write protected %d of %d pages in generation %d\n",
3411 count_write_protect_generation_pages(generation),
3412 count_generation_pages(generation),
3417 /* Garbage collect a generation. If raise is 0 then the remains of the
3418 * generation are not raised to the next generation. */
3420 garbage_collect_generation(int generation, int raise)
3422 unsigned long bytes_freed;
3424 unsigned long static_space_size;
3426 gc_assert(generation <= (NUM_GENERATIONS-1));
3428 /* The oldest generation can't be raised. */
3429 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3431 /* Initialize the weak pointer list. */
3432 weak_pointers = NULL;
3434 /* When a generation is not being raised it is transported to a
3435 * temporary generation (NUM_GENERATIONS), and lowered when
3436 * done. Set up this new generation. There should be no pages
3437 * allocated to it yet. */
3439 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3441 /* Set the global src and dest. generations */
3442 from_space = generation;
3444 new_space = generation+1;
3446 new_space = NUM_GENERATIONS;
3448 /* Change to a new space for allocation, resetting the alloc_start_page */
3449 gc_alloc_generation = new_space;
3450 generations[new_space].alloc_start_page = 0;
3451 generations[new_space].alloc_unboxed_start_page = 0;
3452 generations[new_space].alloc_large_start_page = 0;
3453 generations[new_space].alloc_large_unboxed_start_page = 0;
3455 /* Before any pointers are preserved, the dont_move flags on the
3456 * pages need to be cleared. */
3457 for (i = 0; i < last_free_page; i++)
3458 if(page_table[i].gen==from_space)
3459 page_table[i].dont_move = 0;
3461 /* Un-write-protect the old-space pages. This is essential for the
3462 * promoted pages as they may contain pointers into the old-space
3463 * which need to be scavenged. It also helps avoid unnecessary page
3464 * faults as forwarding pointers are written into them. They need to
3465 * be un-protected anyway before unmapping later. */
3466 unprotect_oldspace();
3468 /* Scavenge the stacks' conservative roots. */
3470 /* there are potentially two stacks for each thread: the main
3471 * stack, which may contain Lisp pointers, and the alternate stack.
3472 * We don't ever run Lisp code on the altstack, but it may
3473 * host a sigcontext with lisp objects in it */
3475 /* what we need to do: (1) find the stack pointer for the main
3476 * stack; scavenge it (2) find the interrupt context on the
3477 * alternate stack that might contain lisp values, and scavenge
3480 /* we assume that none of the preceding applies to the thread that
3481 * initiates GC. If you ever call GC from inside an altstack
3482 * handler, you will lose. */
3483 for_each_thread(th) {
3485 void **esp=(void **)-1;
3486 #ifdef LISP_FEATURE_SB_THREAD
3488 if(th==arch_os_get_current_thread()) {
3489 esp = (void **) &raise;
3492 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3493 for(i=free-1;i>=0;i--) {
3494 os_context_t *c=th->interrupt_contexts[i];
3495 esp1 = (void **) *os_context_register_addr(c,reg_ESP);
3496 if(esp1>=th->control_stack_start&& esp1<th->control_stack_end){
3497 if(esp1<esp) esp=esp1;
3498 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3499 preserve_pointer(*ptr);
3505 esp = (void **) &raise;
3507 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3508 preserve_pointer(*ptr);
3513 if (gencgc_verbose > 1) {
3514 int num_dont_move_pages = count_dont_move_pages();
3516 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3517 num_dont_move_pages,
3518 num_dont_move_pages * PAGE_BYTES);
3522 /* Scavenge all the rest of the roots. */
3524 /* Scavenge the Lisp functions of the interrupt handlers, taking
3525 * care to avoid SIG_DFL and SIG_IGN. */
3526 for_each_thread(th) {
3527 struct interrupt_data *data=th->interrupt_data;
3528 for (i = 0; i < NSIG; i++) {
3529 union interrupt_handler handler = data->interrupt_handlers[i];
3530 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3531 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3532 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3536 /* Scavenge the binding stacks. */
3539 for_each_thread(th) {
3540 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3541 th->binding_stack_start;
3542 scavenge((lispobj *) th->binding_stack_start,len);
3543 #ifdef LISP_FEATURE_SB_THREAD
3544 /* do the tls as well */
3545 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3546 (sizeof (struct thread))/(sizeof (lispobj));
3547 scavenge((lispobj *) (th+1),len);
3552 /* The original CMU CL code had scavenge-read-only-space code
3553 * controlled by the Lisp-level variable
3554 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3555 * wasn't documented under what circumstances it was useful or
3556 * safe to turn it on, so it's been turned off in SBCL. If you
3557 * want/need this functionality, and can test and document it,
3558 * please submit a patch. */
3560 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3561 unsigned long read_only_space_size =
3562 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3563 (lispobj*)READ_ONLY_SPACE_START;
3565 "/scavenge read only space: %d bytes\n",
3566 read_only_space_size * sizeof(lispobj)));
3567 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3571 /* Scavenge static space. */
3573 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3574 (lispobj *)STATIC_SPACE_START;
3575 if (gencgc_verbose > 1) {
3577 "/scavenge static space: %d bytes\n",
3578 static_space_size * sizeof(lispobj)));
3580 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3582 /* All generations but the generation being GCed need to be
3583 * scavenged. The new_space generation needs special handling as
3584 * objects may be moved in - it is handled separately below. */
3585 for (i = 0; i < NUM_GENERATIONS; i++) {
3586 if ((i != generation) && (i != new_space)) {
3587 scavenge_generation(i);
3591 /* Finally scavenge the new_space generation. Keep going until no
3592 * more objects are moved into the new generation */
3593 scavenge_newspace_generation(new_space);
3595 /* FIXME: I tried reenabling this check when debugging unrelated
3596 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3597 * Since the current GC code seems to work well, I'm guessing that
3598 * this debugging code is just stale, but I haven't tried to
3599 * figure it out. It should be figured out and then either made to
3600 * work or just deleted. */
3601 #define RESCAN_CHECK 0
3603 /* As a check re-scavenge the newspace once; no new objects should
3606 int old_bytes_allocated = bytes_allocated;
3607 int bytes_allocated;
3609 /* Start with a full scavenge. */
3610 scavenge_newspace_generation_one_scan(new_space);
3612 /* Flush the current regions, updating the tables. */
3613 gc_alloc_update_all_page_tables();
3615 bytes_allocated = bytes_allocated - old_bytes_allocated;
3617 if (bytes_allocated != 0) {
3618 lose("Rescan of new_space allocated %d more bytes.",
3624 scan_weak_pointers();
3626 /* Flush the current regions, updating the tables. */
3627 gc_alloc_update_all_page_tables();
3629 /* Free the pages in oldspace, but not those marked dont_move. */
3630 bytes_freed = free_oldspace();
3632 /* If the GC is not raising the age then lower the generation back
3633 * to its normal generation number */
3635 for (i = 0; i < last_free_page; i++)
3636 if ((page_table[i].bytes_used != 0)
3637 && (page_table[i].gen == NUM_GENERATIONS))
3638 page_table[i].gen = generation;
3639 gc_assert(generations[generation].bytes_allocated == 0);
3640 generations[generation].bytes_allocated =
3641 generations[NUM_GENERATIONS].bytes_allocated;
3642 generations[NUM_GENERATIONS].bytes_allocated = 0;
3645 /* Reset the alloc_start_page for generation. */
3646 generations[generation].alloc_start_page = 0;
3647 generations[generation].alloc_unboxed_start_page = 0;
3648 generations[generation].alloc_large_start_page = 0;
3649 generations[generation].alloc_large_unboxed_start_page = 0;
3651 if (generation >= verify_gens) {
3655 verify_dynamic_space();
3658 /* Set the new gc trigger for the GCed generation. */
3659 generations[generation].gc_trigger =
3660 generations[generation].bytes_allocated
3661 + generations[generation].bytes_consed_between_gc;
3664 generations[generation].num_gc = 0;
3666 ++generations[generation].num_gc;
3669 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3671 update_x86_dynamic_space_free_pointer(void)
3676 for (i = 0; i < NUM_PAGES; i++)
3677 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3678 && (page_table[i].bytes_used != 0))
3681 last_free_page = last_page+1;
3683 SetSymbolValue(ALLOCATION_POINTER,
3684 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3685 return 0; /* dummy value: return something ... */
3688 /* GC all generations newer than last_gen, raising the objects in each
3689 * to the next older generation - we finish when all generations below
3690 * last_gen are empty. Then if last_gen is due for a GC, or if
3691 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3692 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3694 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3695 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3698 collect_garbage(unsigned last_gen)
3705 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3707 if (last_gen > NUM_GENERATIONS) {
3709 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3714 /* Flush the alloc regions updating the tables. */
3715 gc_alloc_update_all_page_tables();
3717 /* Verify the new objects created by Lisp code. */
3718 if (pre_verify_gen_0) {
3719 FSHOW((stderr, "pre-checking generation 0\n"));
3720 verify_generation(0);
3723 if (gencgc_verbose > 1)
3724 print_generation_stats(0);
3727 /* Collect the generation. */
3729 if (gen >= gencgc_oldest_gen_to_gc) {
3730 /* Never raise the oldest generation. */
3735 || (generations[gen].num_gc >= generations[gen].trigger_age);
3738 if (gencgc_verbose > 1) {
3740 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3743 generations[gen].bytes_allocated,
3744 generations[gen].gc_trigger,
3745 generations[gen].num_gc));
3748 /* If an older generation is being filled, then update its
3751 generations[gen+1].cum_sum_bytes_allocated +=
3752 generations[gen+1].bytes_allocated;
3755 garbage_collect_generation(gen, raise);
3757 /* Reset the memory age cum_sum. */
3758 generations[gen].cum_sum_bytes_allocated = 0;
3760 if (gencgc_verbose > 1) {
3761 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3762 print_generation_stats(0);
3766 } while ((gen <= gencgc_oldest_gen_to_gc)
3767 && ((gen < last_gen)
3768 || ((gen <= gencgc_oldest_gen_to_gc)
3770 && (generations[gen].bytes_allocated
3771 > generations[gen].gc_trigger)
3772 && (gen_av_mem_age(gen)
3773 > generations[gen].min_av_mem_age))));
3775 /* Now if gen-1 was raised all generations before gen are empty.
3776 * If it wasn't raised then all generations before gen-1 are empty.
3778 * Now objects within this gen's pages cannot point to younger
3779 * generations unless they are written to. This can be exploited
3780 * by write-protecting the pages of gen; then when younger
3781 * generations are GCed only the pages which have been written
3786 gen_to_wp = gen - 1;
3788 /* There's not much point in WPing pages in generation 0 as it is
3789 * never scavenged (except promoted pages). */
3790 if ((gen_to_wp > 0) && enable_page_protection) {
3791 /* Check that they are all empty. */
3792 for (i = 0; i < gen_to_wp; i++) {
3793 if (generations[i].bytes_allocated)
3794 lose("trying to write-protect gen. %d when gen. %d nonempty",
3797 write_protect_generation_pages(gen_to_wp);
3800 /* Set gc_alloc() back to generation 0. The current regions should
3801 * be flushed after the above GCs. */
3802 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3803 gc_alloc_generation = 0;
3805 update_x86_dynamic_space_free_pointer();
3806 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3808 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3810 SHOW("returning from collect_garbage");
3813 /* This is called by Lisp PURIFY when it is finished. All live objects
3814 * will have been moved to the RO and Static heaps. The dynamic space
3815 * will need a full re-initialization. We don't bother having Lisp
3816 * PURIFY flush the current gc_alloc() region, as the page_tables are
3817 * re-initialized, and every page is zeroed to be sure. */
3823 if (gencgc_verbose > 1)
3824 SHOW("entering gc_free_heap");
3826 for (page = 0; page < NUM_PAGES; page++) {
3827 /* Skip free pages which should already be zero filled. */
3828 if (page_table[page].allocated != FREE_PAGE_FLAG) {
3829 void *page_start, *addr;
3831 /* Mark the page free. The other slots are assumed invalid
3832 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3833 * should not be write-protected -- except that the
3834 * generation is used for the current region but it sets
3836 page_table[page].allocated = FREE_PAGE_FLAG;
3837 page_table[page].bytes_used = 0;
3839 /* Zero the page. */
3840 page_start = (void *)page_address(page);
3842 /* First, remove any write-protection. */
3843 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3844 page_table[page].write_protected = 0;
3846 os_invalidate(page_start,PAGE_BYTES);
3847 addr = os_validate(page_start,PAGE_BYTES);
3848 if (addr == NULL || addr != page_start) {
3849 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3853 } else if (gencgc_zero_check_during_free_heap) {
3854 /* Double-check that the page is zero filled. */
3856 gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
3857 gc_assert(page_table[page].bytes_used == 0);
3858 page_start = (int *)page_address(page);
3859 for (i=0; i<1024; i++) {
3860 if (page_start[i] != 0) {
3861 lose("free region not zero at %x", page_start + i);
3867 bytes_allocated = 0;
3869 /* Initialize the generations. */
3870 for (page = 0; page < NUM_GENERATIONS; page++) {
3871 generations[page].alloc_start_page = 0;
3872 generations[page].alloc_unboxed_start_page = 0;
3873 generations[page].alloc_large_start_page = 0;
3874 generations[page].alloc_large_unboxed_start_page = 0;
3875 generations[page].bytes_allocated = 0;
3876 generations[page].gc_trigger = 2000000;
3877 generations[page].num_gc = 0;
3878 generations[page].cum_sum_bytes_allocated = 0;
3881 if (gencgc_verbose > 1)
3882 print_generation_stats(0);
3884 /* Initialize gc_alloc(). */
3885 gc_alloc_generation = 0;
3887 gc_set_region_empty(&boxed_region);
3888 gc_set_region_empty(&unboxed_region);
3891 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3893 if (verify_after_free_heap) {
3894 /* Check whether purify has left any bad pointers. */
3896 SHOW("checking after free_heap\n");
3907 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
3908 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
3909 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
3911 heap_base = (void*)DYNAMIC_SPACE_START;
3913 /* Initialize each page structure. */
3914 for (i = 0; i < NUM_PAGES; i++) {
3915 /* Initialize all pages as free. */
3916 page_table[i].allocated = FREE_PAGE_FLAG;
3917 page_table[i].bytes_used = 0;
3919 /* Pages are not write-protected at startup. */
3920 page_table[i].write_protected = 0;
3923 bytes_allocated = 0;
3925 /* Initialize the generations.
3927 * FIXME: very similar to code in gc_free_heap(), should be shared */
3928 for (i = 0; i < NUM_GENERATIONS; i++) {
3929 generations[i].alloc_start_page = 0;
3930 generations[i].alloc_unboxed_start_page = 0;
3931 generations[i].alloc_large_start_page = 0;
3932 generations[i].alloc_large_unboxed_start_page = 0;
3933 generations[i].bytes_allocated = 0;
3934 generations[i].gc_trigger = 2000000;
3935 generations[i].num_gc = 0;
3936 generations[i].cum_sum_bytes_allocated = 0;
3937 /* the tune-able parameters */
3938 generations[i].bytes_consed_between_gc = 2000000;
3939 generations[i].trigger_age = 1;
3940 generations[i].min_av_mem_age = 0.75;
3943 /* Initialize gc_alloc. */
3944 gc_alloc_generation = 0;
3945 gc_set_region_empty(&boxed_region);
3946 gc_set_region_empty(&unboxed_region);
3952 /* Pick up the dynamic space from after a core load.
3954 * The ALLOCATION_POINTER points to the end of the dynamic space.
3958 gencgc_pickup_dynamic(void)
3961 int alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
3962 lispobj *prev=(lispobj *)page_address(page);
3965 lispobj *first,*ptr= (lispobj *)page_address(page);
3966 page_table[page].allocated = BOXED_PAGE_FLAG;
3967 page_table[page].gen = 0;
3968 page_table[page].bytes_used = PAGE_BYTES;
3969 page_table[page].large_object = 0;
3971 first=search_space(prev,(ptr+2)-prev,ptr);
3972 if(ptr == first) prev=ptr;
3973 page_table[page].first_object_offset =
3974 (void *)prev - page_address(page);
3976 } while (page_address(page) < alloc_ptr);
3978 generations[0].bytes_allocated = PAGE_BYTES*page;
3979 bytes_allocated = PAGE_BYTES*page;
3985 gc_initialize_pointers(void)
3987 gencgc_pickup_dynamic();
3993 /* alloc(..) is the external interface for memory allocation. It
3994 * allocates to generation 0. It is not called from within the garbage
3995 * collector as it is only external uses that need the check for heap
3996 * size (GC trigger) and to disable the interrupts (interrupts are
3997 * always disabled during a GC).
3999 * The vops that call alloc(..) assume that the returned space is zero-filled.
4000 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4002 * The check for a GC trigger is only performed when the current
4003 * region is full, so in most cases it's not needed. */
4008 struct thread *th=arch_os_get_current_thread();
4009 struct alloc_region *region=
4010 #ifdef LISP_FEATURE_SB_THREAD
4011 th ? &(th->alloc_region) : &boxed_region;
4016 void *new_free_pointer;
4018 /* Check for alignment allocation problems. */
4019 gc_assert((((unsigned)region->free_pointer & 0x7) == 0)
4020 && ((nbytes & 0x7) == 0));
4022 /* there are a few places in the C code that allocate data in the
4023 * heap before Lisp starts. This is before interrupts are enabled,
4024 * so we don't need to check for pseudo-atomic */
4025 #ifdef LISP_FEATURE_SB_THREAD
4026 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4028 fprintf(stderr, "fatal error in thread 0x%x, pid=%d\n",
4030 __asm__("movl %fs,%0" : "=r" (fs) : );
4031 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4032 debug_get_fs(),th->tls_cookie);
4033 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4036 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4039 /* maybe we can do this quickly ... */
4040 new_free_pointer = region->free_pointer + nbytes;
4041 if (new_free_pointer <= region->end_addr) {
4042 new_obj = (void*)(region->free_pointer);
4043 region->free_pointer = new_free_pointer;
4044 return(new_obj); /* yup */
4047 /* we have to go the long way around, it seems. Check whether
4048 * we should GC in the near future
4050 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4051 /* set things up so that GC happens when we finish the PA
4052 * section. We only do this if there wasn't a pending handler
4053 * already, in case it was a gc. If it wasn't a GC, the next
4054 * allocation will get us back to this point anyway, so no harm done
4056 struct interrupt_data *data=th->interrupt_data;
4057 if(!data->pending_handler)
4058 maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0);
4060 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4065 * shared support for the OS-dependent signal handlers which
4066 * catch GENCGC-related write-protect violations
4069 void unhandled_sigmemoryfault(void);
4071 /* Depending on which OS we're running under, different signals might
4072 * be raised for a violation of write protection in the heap. This
4073 * function factors out the common generational GC magic which needs
4074 * to invoked in this case, and should be called from whatever signal
4075 * handler is appropriate for the OS we're running under.
4077 * Return true if this signal is a normal generational GC thing that
4078 * we were able to handle, or false if it was abnormal and control
4079 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4082 gencgc_handle_wp_violation(void* fault_addr)
4084 int page_index = find_page_index(fault_addr);
4086 #ifdef QSHOW_SIGNALS
4087 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4088 fault_addr, page_index));
4091 /* Check whether the fault is within the dynamic space. */
4092 if (page_index == (-1)) {
4094 /* It can be helpful to be able to put a breakpoint on this
4095 * case to help diagnose low-level problems. */
4096 unhandled_sigmemoryfault();
4098 /* not within the dynamic space -- not our responsibility */
4102 if (page_table[page_index].write_protected) {
4103 /* Unprotect the page. */
4104 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4105 page_table[page_index].write_protected_cleared = 1;
4106 page_table[page_index].write_protected = 0;
4108 /* The only acceptable reason for this signal on a heap
4109 * access is that GENCGC write-protected the page.
4110 * However, if two CPUs hit a wp page near-simultaneously,
4111 * we had better not have the second one lose here if it
4112 * does this test after the first one has already set wp=0
4114 if(page_table[page_index].write_protected_cleared != 1)
4115 lose("fault in heap page not marked as write-protected");
4117 /* Don't worry, we can handle it. */
4121 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4122 * it's not just a case of the program hitting the write barrier, and
4123 * are about to let Lisp deal with it. It's basically just a
4124 * convenient place to set a gdb breakpoint. */
4126 unhandled_sigmemoryfault()
4129 void gc_alloc_update_all_page_tables(void)
4131 /* Flush the alloc regions updating the tables. */
4134 gc_alloc_update_page_tables(0, &th->alloc_region);
4135 gc_alloc_update_page_tables(1, &unboxed_region);
4136 gc_alloc_update_page_tables(0, &boxed_region);
4139 gc_set_region_empty(struct alloc_region *region)
4141 region->first_page = 0;
4142 region->last_page = -1;
4143 region->start_addr = page_address(0);
4144 region->free_pointer = page_address(0);
4145 region->end_addr = page_address(0);