2 * GENerational Conservative Garbage Collector for SBCL x86
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 * For a review of garbage collection techniques (e.g. generational
18 * GC) and terminology (e.g. "scavenging") see Paul R. Wilson,
19 * "Uniprocessor Garbage Collection Techniques". As of 20000618, this
20 * had been accepted for _ACM Computing Surveys_ and was available
21 * as a PostScript preprint through
22 * <http://www.cs.utexas.edu/users/oops/papers.html>
24 * <ftp://ftp.cs.utexas.edu/pub/garbage/bigsurv.ps>.
36 #include "interrupt.h"
41 #include "gc-internal.h"
43 #include "genesis/vector.h"
44 #include "genesis/weak-pointer.h"
45 #include "genesis/simple-fun.h"
47 /* assembly language stub that executes trap_PendingInterrupt */
48 void do_pending_interrupt(void);
50 /* forward declarations */
51 int gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed);
52 void gc_set_region_empty(struct alloc_region *region);
53 void gc_alloc_update_all_page_tables(void);
54 static void gencgc_pickup_dynamic(void);
55 boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
62 /* the number of actual generations. (The number of 'struct
63 * generation' objects is one more than this, because one object
64 * serves as scratch when GC'ing.) */
65 #define NUM_GENERATIONS 6
67 /* Should we use page protection to help avoid the scavenging of pages
68 * that don't have pointers to younger generations? */
69 boolean enable_page_protection = 1;
71 /* Should we unmap a page and re-mmap it to have it zero filled? */
72 #if defined(__FreeBSD__) || defined(__OpenBSD__)
73 /* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
74 * so don't unmap there.
76 * The CMU CL comment didn't specify a version, but was probably an
77 * old version of FreeBSD (pre-4.0), so this might no longer be true.
78 * OTOH, if it is true, this behavior might exist on OpenBSD too, so
79 * for now we don't unmap there either. -- WHN 2001-04-07 */
80 boolean gencgc_unmap_zero = 0;
82 boolean gencgc_unmap_zero = 1;
85 /* the minimum size (in bytes) for a large object*/
86 unsigned large_object_size = 4 * PAGE_BYTES;
95 /* the verbosity level. All non-error messages are disabled at level 0;
96 * and only a few rare messages are printed at level 1. */
97 unsigned gencgc_verbose = (QSHOW ? 1 : 0);
99 /* FIXME: At some point enable the various error-checking things below
100 * and see what they say. */
102 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
103 * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
104 int verify_gens = NUM_GENERATIONS;
106 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
107 boolean pre_verify_gen_0 = 0;
109 /* Should we check for bad pointers after gc_free_heap is called
110 * from Lisp PURIFY? */
111 boolean verify_after_free_heap = 0;
113 /* Should we print a note when code objects are found in the dynamic space
114 * during a heap verify? */
115 boolean verify_dynamic_code_check = 0;
117 /* Should we check code objects for fixup errors after they are transported? */
118 boolean check_code_fixups = 0;
120 /* Should we check that newly allocated regions are zero filled? */
121 boolean gencgc_zero_check = 0;
123 /* Should we check that the free space is zero filled? */
124 boolean gencgc_enable_verify_zero_fill = 0;
126 /* Should we check that free pages are zero filled during gc_free_heap
127 * called after Lisp PURIFY? */
128 boolean gencgc_zero_check_during_free_heap = 0;
131 * GC structures and variables
134 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
135 unsigned long bytes_allocated = 0;
136 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
137 unsigned long auto_gc_trigger = 0;
139 /* the source and destination generations. These are set before a GC starts
145 /* An array of page structures is statically allocated.
146 * This helps quickly map between an address its page structure.
147 * NUM_PAGES is set from the size of the dynamic space. */
148 struct page page_table[NUM_PAGES];
150 /* To map addresses to page structures the address of the first page
152 static void *heap_base = NULL;
155 /* Calculate the start address for the given page number. */
157 page_address(int page_num)
159 return (heap_base + (page_num * PAGE_BYTES));
162 /* Find the page index within the page_table for the given
163 * address. Return -1 on failure. */
165 find_page_index(void *addr)
167 int index = addr-heap_base;
170 index = ((unsigned int)index)/PAGE_BYTES;
171 if (index < NUM_PAGES)
178 /* a structure to hold the state of a generation */
181 /* the first page that gc_alloc() checks on its next call */
182 int alloc_start_page;
184 /* the first page that gc_alloc_unboxed() checks on its next call */
185 int alloc_unboxed_start_page;
187 /* the first page that gc_alloc_large (boxed) considers on its next
188 * call. (Although it always allocates after the boxed_region.) */
189 int alloc_large_start_page;
191 /* the first page that gc_alloc_large (unboxed) considers on its
192 * next call. (Although it always allocates after the
193 * current_unboxed_region.) */
194 int alloc_large_unboxed_start_page;
196 /* the bytes allocated to this generation */
199 /* the number of bytes at which to trigger a GC */
202 /* to calculate a new level for gc_trigger */
203 int bytes_consed_between_gc;
205 /* the number of GCs since the last raise */
208 /* the average age after which a GC will raise objects to the
212 /* the cumulative sum of the bytes allocated to this generation. It is
213 * cleared after a GC on this generations, and update before new
214 * objects are added from a GC of a younger generation. Dividing by
215 * the bytes_allocated will give the average age of the memory in
216 * this generation since its last GC. */
217 int cum_sum_bytes_allocated;
219 /* a minimum average memory age before a GC will occur helps
220 * prevent a GC when a large number of new live objects have been
221 * added, in which case a GC could be a waste of time */
222 double min_av_mem_age;
224 /* the number of actual generations. (The number of 'struct
225 * generation' objects is one more than this, because one object
226 * serves as scratch when GC'ing.) */
227 #define NUM_GENERATIONS 6
229 /* an array of generation structures. There needs to be one more
230 * generation structure than actual generations as the oldest
231 * generation is temporarily raised then lowered. */
232 struct generation generations[NUM_GENERATIONS+1];
234 /* the oldest generation that is will currently be GCed by default.
235 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
237 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
239 * Setting this to 0 effectively disables the generational nature of
240 * the GC. In some applications generational GC may not be useful
241 * because there are no long-lived objects.
243 * An intermediate value could be handy after moving long-lived data
244 * into an older generation so an unnecessary GC of this long-lived
245 * data can be avoided. */
246 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
248 /* The maximum free page in the heap is maintained and used to update
249 * ALLOCATION_POINTER which is used by the room function to limit its
250 * search of the heap. XX Gencgc obviously needs to be better
251 * integrated with the Lisp code. */
252 static int last_free_page;
254 /* This lock is to prevent multiple threads from simultaneously
255 * allocating new regions which overlap each other. Note that the
256 * majority of GC is single-threaded, but alloc() may be called from
257 * >1 thread at a time and must be thread-safe. This lock must be
258 * seized before all accesses to generations[] or to parts of
259 * page_table[] that other threads may want to see */
261 static lispobj free_pages_lock=0;
265 * miscellaneous heap functions
268 /* Count the number of pages which are write-protected within the
269 * given generation. */
271 count_write_protect_generation_pages(int generation)
276 for (i = 0; i < last_free_page; i++)
277 if ((page_table[i].allocated != FREE_PAGE_FLAG)
278 && (page_table[i].gen == generation)
279 && (page_table[i].write_protected == 1))
284 /* Count the number of pages within the given generation. */
286 count_generation_pages(int generation)
291 for (i = 0; i < last_free_page; i++)
292 if ((page_table[i].allocated != 0)
293 && (page_table[i].gen == generation))
298 /* Count the number of dont_move pages. */
300 count_dont_move_pages(void)
304 for (i = 0; i < last_free_page; i++) {
305 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
312 /* Work through the pages and add up the number of bytes used for the
313 * given generation. */
315 count_generation_bytes_allocated (int gen)
319 for (i = 0; i < last_free_page; i++) {
320 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
321 result += page_table[i].bytes_used;
326 /* Return the average age of the memory in a generation. */
328 gen_av_mem_age(int gen)
330 if (generations[gen].bytes_allocated == 0)
334 ((double)generations[gen].cum_sum_bytes_allocated)
335 / ((double)generations[gen].bytes_allocated);
338 void fpu_save(int *); /* defined in x86-assem.S */
339 void fpu_restore(int *); /* defined in x86-assem.S */
340 /* The verbose argument controls how much to print: 0 for normal
341 * level of detail; 1 for debugging. */
343 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
348 /* This code uses the FP instructions which may be set up for Lisp
349 * so they need to be saved and reset for C. */
352 /* number of generations to print */
354 gens = NUM_GENERATIONS+1;
356 gens = NUM_GENERATIONS;
358 /* Print the heap stats. */
360 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
362 for (i = 0; i < gens; i++) {
366 int large_boxed_cnt = 0;
367 int large_unboxed_cnt = 0;
370 for (j = 0; j < last_free_page; j++)
371 if (page_table[j].gen == i) {
373 /* Count the number of boxed pages within the given
375 if (page_table[j].allocated & BOXED_PAGE_FLAG) {
376 if (page_table[j].large_object)
381 if(page_table[j].dont_move) pinned_cnt++;
382 /* Count the number of unboxed pages within the given
384 if (page_table[j].allocated & UNBOXED_PAGE_FLAG) {
385 if (page_table[j].large_object)
392 gc_assert(generations[i].bytes_allocated
393 == count_generation_bytes_allocated(i));
395 " %1d: %5d %5d %5d %5d %5d %8d %5d %8d %4d %3d %7.4f\n",
397 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
399 generations[i].bytes_allocated,
400 (count_generation_pages(i)*PAGE_BYTES
401 - generations[i].bytes_allocated),
402 generations[i].gc_trigger,
403 count_write_protect_generation_pages(i),
404 generations[i].num_gc,
407 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
409 fpu_restore(fpu_state);
413 * allocation routines
417 * To support quick and inline allocation, regions of memory can be
418 * allocated and then allocated from with just a free pointer and a
419 * check against an end address.
421 * Since objects can be allocated to spaces with different properties
422 * e.g. boxed/unboxed, generation, ages; there may need to be many
423 * allocation regions.
425 * Each allocation region may be start within a partly used page. Many
426 * features of memory use are noted on a page wise basis, e.g. the
427 * generation; so if a region starts within an existing allocated page
428 * it must be consistent with this page.
430 * During the scavenging of the newspace, objects will be transported
431 * into an allocation region, and pointers updated to point to this
432 * allocation region. It is possible that these pointers will be
433 * scavenged again before the allocation region is closed, e.g. due to
434 * trans_list which jumps all over the place to cleanup the list. It
435 * is important to be able to determine properties of all objects
436 * pointed to when scavenging, e.g to detect pointers to the oldspace.
437 * Thus it's important that the allocation regions have the correct
438 * properties set when allocated, and not just set when closed. The
439 * region allocation routines return regions with the specified
440 * properties, and grab all the pages, setting their properties
441 * appropriately, except that the amount used is not known.
443 * These regions are used to support quicker allocation using just a
444 * free pointer. The actual space used by the region is not reflected
445 * in the pages tables until it is closed. It can't be scavenged until
448 * When finished with the region it should be closed, which will
449 * update the page tables for the actual space used returning unused
450 * space. Further it may be noted in the new regions which is
451 * necessary when scavenging the newspace.
453 * Large objects may be allocated directly without an allocation
454 * region, the page tables are updated immediately.
456 * Unboxed objects don't contain pointers to other objects and so
457 * don't need scavenging. Further they can't contain pointers to
458 * younger generations so WP is not needed. By allocating pages to
459 * unboxed objects the whole page never needs scavenging or
460 * write-protecting. */
462 /* We are only using two regions at present. Both are for the current
463 * newspace generation. */
464 struct alloc_region boxed_region;
465 struct alloc_region unboxed_region;
467 /* The generation currently being allocated to. */
468 static int gc_alloc_generation;
470 /* Find a new region with room for at least the given number of bytes.
472 * It starts looking at the current generation's alloc_start_page. So
473 * may pick up from the previous region if there is enough space. This
474 * keeps the allocation contiguous when scavenging the newspace.
476 * The alloc_region should have been closed by a call to
477 * gc_alloc_update_page_tables(), and will thus be in an empty state.
479 * To assist the scavenging functions write-protected pages are not
480 * used. Free pages should not be write-protected.
482 * It is critical to the conservative GC that the start of regions be
483 * known. To help achieve this only small regions are allocated at a
486 * During scavenging, pointers may be found to within the current
487 * region and the page generation must be set so that pointers to the
488 * from space can be recognized. Therefore the generation of pages in
489 * the region are set to gc_alloc_generation. To prevent another
490 * allocation call using the same pages, all the pages in the region
491 * are allocated, although they will initially be empty.
494 gc_alloc_new_region(int nbytes, int unboxed, struct alloc_region *alloc_region)
503 "/alloc_new_region for %d bytes from gen %d\n",
504 nbytes, gc_alloc_generation));
507 /* Check that the region is in a reset state. */
508 gc_assert((alloc_region->first_page == 0)
509 && (alloc_region->last_page == -1)
510 && (alloc_region->free_pointer == alloc_region->end_addr));
511 get_spinlock(&free_pages_lock,(int) alloc_region);
514 generations[gc_alloc_generation].alloc_unboxed_start_page;
517 generations[gc_alloc_generation].alloc_start_page;
519 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
520 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
521 + PAGE_BYTES*(last_page-first_page);
523 /* Set up the alloc_region. */
524 alloc_region->first_page = first_page;
525 alloc_region->last_page = last_page;
526 alloc_region->start_addr = page_table[first_page].bytes_used
527 + page_address(first_page);
528 alloc_region->free_pointer = alloc_region->start_addr;
529 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
531 /* Set up the pages. */
533 /* The first page may have already been in use. */
534 if (page_table[first_page].bytes_used == 0) {
536 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
538 page_table[first_page].allocated = BOXED_PAGE_FLAG;
539 page_table[first_page].gen = gc_alloc_generation;
540 page_table[first_page].large_object = 0;
541 page_table[first_page].first_object_offset = 0;
545 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
547 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
548 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
550 gc_assert(page_table[first_page].gen == gc_alloc_generation);
551 gc_assert(page_table[first_page].large_object == 0);
553 for (i = first_page+1; i <= last_page; i++) {
555 page_table[i].allocated = UNBOXED_PAGE_FLAG;
557 page_table[i].allocated = BOXED_PAGE_FLAG;
558 page_table[i].gen = gc_alloc_generation;
559 page_table[i].large_object = 0;
560 /* This may not be necessary for unboxed regions (think it was
562 page_table[i].first_object_offset =
563 alloc_region->start_addr - page_address(i);
564 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
566 /* Bump up last_free_page. */
567 if (last_page+1 > last_free_page) {
568 last_free_page = last_page+1;
569 SetSymbolValue(ALLOCATION_POINTER,
570 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
573 release_spinlock(&free_pages_lock);
575 /* we can do this after releasing free_pages_lock */
576 if (gencgc_zero_check) {
578 for (p = (int *)alloc_region->start_addr;
579 p < (int *)alloc_region->end_addr; p++) {
581 /* KLUDGE: It would be nice to use %lx and explicit casts
582 * (long) in code like this, so that it is less likely to
583 * break randomly when running on a machine with different
584 * word sizes. -- WHN 19991129 */
585 lose("The new region at %x is not zero.", p);
592 /* If the record_new_objects flag is 2 then all new regions created
595 * If it's 1 then then it is only recorded if the first page of the
596 * current region is <= new_areas_ignore_page. This helps avoid
597 * unnecessary recording when doing full scavenge pass.
599 * The new_object structure holds the page, byte offset, and size of
600 * new regions of objects. Each new area is placed in the array of
601 * these structures pointer to by new_areas. new_areas_index holds the
602 * offset into new_areas.
604 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
605 * later code must detect this and handle it, probably by doing a full
606 * scavenge of a generation. */
607 #define NUM_NEW_AREAS 512
608 static int record_new_objects = 0;
609 static int new_areas_ignore_page;
615 static struct new_area (*new_areas)[];
616 static int new_areas_index;
619 /* Add a new area to new_areas. */
621 add_new_area(int first_page, int offset, int size)
623 unsigned new_area_start,c;
626 /* Ignore if full. */
627 if (new_areas_index >= NUM_NEW_AREAS)
630 switch (record_new_objects) {
634 if (first_page > new_areas_ignore_page)
643 new_area_start = PAGE_BYTES*first_page + offset;
645 /* Search backwards for a prior area that this follows from. If
646 found this will save adding a new area. */
647 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
649 PAGE_BYTES*((*new_areas)[i].page)
650 + (*new_areas)[i].offset
651 + (*new_areas)[i].size;
653 "/add_new_area S1 %d %d %d %d\n",
654 i, c, new_area_start, area_end));*/
655 if (new_area_start == area_end) {
657 "/adding to [%d] %d %d %d with %d %d %d:\n",
659 (*new_areas)[i].page,
660 (*new_areas)[i].offset,
661 (*new_areas)[i].size,
665 (*new_areas)[i].size += size;
670 (*new_areas)[new_areas_index].page = first_page;
671 (*new_areas)[new_areas_index].offset = offset;
672 (*new_areas)[new_areas_index].size = size;
674 "/new_area %d page %d offset %d size %d\n",
675 new_areas_index, first_page, offset, size));*/
678 /* Note the max new_areas used. */
679 if (new_areas_index > max_new_areas)
680 max_new_areas = new_areas_index;
683 /* Update the tables for the alloc_region. The region may be added to
686 * When done the alloc_region is set up so that the next quick alloc
687 * will fail safely and thus a new region will be allocated. Further
688 * it is safe to try to re-update the page table of this reset
691 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
697 int orig_first_page_bytes_used;
702 first_page = alloc_region->first_page;
704 /* Catch an unused alloc_region. */
705 if ((first_page == 0) && (alloc_region->last_page == -1))
708 next_page = first_page+1;
710 get_spinlock(&free_pages_lock,(int) alloc_region);
711 if (alloc_region->free_pointer != alloc_region->start_addr) {
712 /* some bytes were allocated in the region */
713 orig_first_page_bytes_used = page_table[first_page].bytes_used;
715 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
717 /* All the pages used need to be updated */
719 /* Update the first page. */
721 /* If the page was free then set up the gen, and
722 * first_object_offset. */
723 if (page_table[first_page].bytes_used == 0)
724 gc_assert(page_table[first_page].first_object_offset == 0);
725 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
728 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
730 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
731 gc_assert(page_table[first_page].gen == gc_alloc_generation);
732 gc_assert(page_table[first_page].large_object == 0);
736 /* Calculate the number of bytes used in this page. This is not
737 * always the number of new bytes, unless it was free. */
739 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
740 bytes_used = PAGE_BYTES;
743 page_table[first_page].bytes_used = bytes_used;
744 byte_cnt += bytes_used;
747 /* All the rest of the pages should be free. We need to set their
748 * first_object_offset pointer to the start of the region, and set
751 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
753 gc_assert(page_table[next_page].allocated==UNBOXED_PAGE_FLAG);
755 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
756 gc_assert(page_table[next_page].bytes_used == 0);
757 gc_assert(page_table[next_page].gen == gc_alloc_generation);
758 gc_assert(page_table[next_page].large_object == 0);
760 gc_assert(page_table[next_page].first_object_offset ==
761 alloc_region->start_addr - page_address(next_page));
763 /* Calculate the number of bytes used in this page. */
765 if ((bytes_used = (alloc_region->free_pointer
766 - page_address(next_page)))>PAGE_BYTES) {
767 bytes_used = PAGE_BYTES;
770 page_table[next_page].bytes_used = bytes_used;
771 byte_cnt += bytes_used;
776 region_size = alloc_region->free_pointer - alloc_region->start_addr;
777 bytes_allocated += region_size;
778 generations[gc_alloc_generation].bytes_allocated += region_size;
780 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
782 /* Set the generations alloc restart page to the last page of
785 generations[gc_alloc_generation].alloc_unboxed_start_page =
788 generations[gc_alloc_generation].alloc_start_page = next_page-1;
790 /* Add the region to the new_areas if requested. */
792 add_new_area(first_page,orig_first_page_bytes_used, region_size);
796 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
798 gc_alloc_generation));
801 /* There are no bytes allocated. Unallocate the first_page if
802 * there are 0 bytes_used. */
803 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
804 if (page_table[first_page].bytes_used == 0)
805 page_table[first_page].allocated = FREE_PAGE_FLAG;
808 /* Unallocate any unused pages. */
809 while (next_page <= alloc_region->last_page) {
810 gc_assert(page_table[next_page].bytes_used == 0);
811 page_table[next_page].allocated = FREE_PAGE_FLAG;
814 release_spinlock(&free_pages_lock);
815 /* alloc_region is per-thread, we're ok to do this unlocked */
816 gc_set_region_empty(alloc_region);
819 static inline void *gc_quick_alloc(int nbytes);
821 /* Allocate a possibly large object. */
823 gc_alloc_large(int nbytes, int unboxed, struct alloc_region *alloc_region)
827 int orig_first_page_bytes_used;
833 get_spinlock(&free_pages_lock,(int) alloc_region);
837 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
839 first_page = generations[gc_alloc_generation].alloc_large_start_page;
841 if (first_page <= alloc_region->last_page) {
842 first_page = alloc_region->last_page+1;
845 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
847 gc_assert(first_page > alloc_region->last_page);
849 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
852 generations[gc_alloc_generation].alloc_large_start_page = last_page;
854 /* Set up the pages. */
855 orig_first_page_bytes_used = page_table[first_page].bytes_used;
857 /* If the first page was free then set up the gen, and
858 * first_object_offset. */
859 if (page_table[first_page].bytes_used == 0) {
861 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
863 page_table[first_page].allocated = BOXED_PAGE_FLAG;
864 page_table[first_page].gen = gc_alloc_generation;
865 page_table[first_page].first_object_offset = 0;
866 page_table[first_page].large_object = 1;
870 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
872 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
873 gc_assert(page_table[first_page].gen == gc_alloc_generation);
874 gc_assert(page_table[first_page].large_object == 1);
878 /* Calc. the number of bytes used in this page. This is not
879 * always the number of new bytes, unless it was free. */
881 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
882 bytes_used = PAGE_BYTES;
885 page_table[first_page].bytes_used = bytes_used;
886 byte_cnt += bytes_used;
888 next_page = first_page+1;
890 /* All the rest of the pages should be free. We need to set their
891 * first_object_offset pointer to the start of the region, and
892 * set the bytes_used. */
894 gc_assert(page_table[next_page].allocated == FREE_PAGE_FLAG);
895 gc_assert(page_table[next_page].bytes_used == 0);
897 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
899 page_table[next_page].allocated = BOXED_PAGE_FLAG;
900 page_table[next_page].gen = gc_alloc_generation;
901 page_table[next_page].large_object = 1;
903 page_table[next_page].first_object_offset =
904 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
906 /* Calculate the number of bytes used in this page. */
908 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
909 bytes_used = PAGE_BYTES;
912 page_table[next_page].bytes_used = bytes_used;
913 page_table[next_page].write_protected=0;
914 page_table[next_page].dont_move=0;
915 byte_cnt += bytes_used;
919 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
921 bytes_allocated += nbytes;
922 generations[gc_alloc_generation].bytes_allocated += nbytes;
924 /* Add the region to the new_areas if requested. */
926 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
928 /* Bump up last_free_page */
929 if (last_page+1 > last_free_page) {
930 last_free_page = last_page+1;
931 SetSymbolValue(ALLOCATION_POINTER,
932 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
934 release_spinlock(&free_pages_lock);
936 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
940 gc_find_freeish_pages(int *restart_page_ptr, int nbytes, int unboxed)
945 int restart_page=*restart_page_ptr;
948 int large_p=(nbytes>=large_object_size);
949 gc_assert(free_pages_lock);
951 /* Search for a contiguous free space of at least nbytes. If it's
952 * a large object then align it on a page boundary by searching
953 * for a free page. */
956 first_page = restart_page;
958 while ((first_page < NUM_PAGES)
959 && (page_table[first_page].allocated != FREE_PAGE_FLAG))
962 while (first_page < NUM_PAGES) {
963 if(page_table[first_page].allocated == FREE_PAGE_FLAG)
965 if((page_table[first_page].allocated ==
966 (unboxed ? UNBOXED_PAGE_FLAG : BOXED_PAGE_FLAG)) &&
967 (page_table[first_page].large_object == 0) &&
968 (page_table[first_page].gen == gc_alloc_generation) &&
969 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
970 (page_table[first_page].write_protected == 0) &&
971 (page_table[first_page].dont_move == 0)) {
977 if (first_page >= NUM_PAGES) {
979 "Argh! gc_find_free_space failed (first_page), nbytes=%d.\n",
981 print_generation_stats(1);
985 gc_assert(page_table[first_page].write_protected == 0);
987 last_page = first_page;
988 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
990 while (((bytes_found < nbytes)
991 || (!large_p && (num_pages < 2)))
992 && (last_page < (NUM_PAGES-1))
993 && (page_table[last_page+1].allocated == FREE_PAGE_FLAG)) {
996 bytes_found += PAGE_BYTES;
997 gc_assert(page_table[last_page].write_protected == 0);
1000 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
1001 + PAGE_BYTES*(last_page-first_page);
1003 gc_assert(bytes_found == region_size);
1004 restart_page = last_page + 1;
1005 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
1007 /* Check for a failure */
1008 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
1010 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%d.\n",
1012 print_generation_stats(1);
1015 *restart_page_ptr=first_page;
1019 /* Allocate bytes. All the rest of the special-purpose allocation
1020 * functions will eventually call this */
1023 gc_alloc_with_region(int nbytes,int unboxed_p, struct alloc_region *my_region,
1026 void *new_free_pointer;
1028 if(nbytes>=large_object_size)
1029 return gc_alloc_large(nbytes,unboxed_p,my_region);
1031 /* Check whether there is room in the current alloc region. */
1032 new_free_pointer = my_region->free_pointer + nbytes;
1034 if (new_free_pointer <= my_region->end_addr) {
1035 /* If so then allocate from the current alloc region. */
1036 void *new_obj = my_region->free_pointer;
1037 my_region->free_pointer = new_free_pointer;
1039 /* Unless a `quick' alloc was requested, check whether the
1040 alloc region is almost empty. */
1042 (my_region->end_addr - my_region->free_pointer) <= 32) {
1043 /* If so, finished with the current region. */
1044 gc_alloc_update_page_tables(unboxed_p, my_region);
1045 /* Set up a new region. */
1046 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1049 return((void *)new_obj);
1052 /* Else not enough free space in the current region: retry with a
1055 gc_alloc_update_page_tables(unboxed_p, my_region);
1056 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1057 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1060 /* these are only used during GC: all allocation from the mutator calls
1061 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1065 gc_general_alloc(int nbytes,int unboxed_p,int quick_p)
1067 struct alloc_region *my_region =
1068 unboxed_p ? &unboxed_region : &boxed_region;
1069 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1072 static inline void *
1073 gc_quick_alloc(int nbytes)
1075 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1078 static inline void *
1079 gc_quick_alloc_large(int nbytes)
1081 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1084 static inline void *
1085 gc_alloc_unboxed(int nbytes)
1087 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1090 static inline void *
1091 gc_quick_alloc_unboxed(int nbytes)
1093 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1096 static inline void *
1097 gc_quick_alloc_large_unboxed(int nbytes)
1099 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1103 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1106 extern int (*scavtab[256])(lispobj *where, lispobj object);
1107 extern lispobj (*transother[256])(lispobj object);
1108 extern int (*sizetab[256])(lispobj *where);
1110 /* Copy a large boxed object. If the object is in a large object
1111 * region then it is simply promoted, else it is copied. If it's large
1112 * enough then it's copied to a large object region.
1114 * Vectors may have shrunk. If the object is not copied the space
1115 * needs to be reclaimed, and the page_tables corrected. */
1117 copy_large_object(lispobj object, int nwords)
1123 gc_assert(is_lisp_pointer(object));
1124 gc_assert(from_space_p(object));
1125 gc_assert((nwords & 0x01) == 0);
1128 /* Check whether it's in a large object region. */
1129 first_page = find_page_index((void *)object);
1130 gc_assert(first_page >= 0);
1132 if (page_table[first_page].large_object) {
1134 /* Promote the object. */
1136 int remaining_bytes;
1141 /* Note: Any page write-protection must be removed, else a
1142 * later scavenge_newspace may incorrectly not scavenge these
1143 * pages. This would not be necessary if they are added to the
1144 * new areas, but let's do it for them all (they'll probably
1145 * be written anyway?). */
1147 gc_assert(page_table[first_page].first_object_offset == 0);
1149 next_page = first_page;
1150 remaining_bytes = nwords*4;
1151 while (remaining_bytes > PAGE_BYTES) {
1152 gc_assert(page_table[next_page].gen == from_space);
1153 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1154 gc_assert(page_table[next_page].large_object);
1155 gc_assert(page_table[next_page].first_object_offset==
1156 -PAGE_BYTES*(next_page-first_page));
1157 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1159 page_table[next_page].gen = new_space;
1161 /* Remove any write-protection. We should be able to rely
1162 * on the write-protect flag to avoid redundant calls. */
1163 if (page_table[next_page].write_protected) {
1164 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1165 page_table[next_page].write_protected = 0;
1167 remaining_bytes -= PAGE_BYTES;
1171 /* Now only one page remains, but the object may have shrunk
1172 * so there may be more unused pages which will be freed. */
1174 /* The object may have shrunk but shouldn't have grown. */
1175 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1177 page_table[next_page].gen = new_space;
1178 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1180 /* Adjust the bytes_used. */
1181 old_bytes_used = page_table[next_page].bytes_used;
1182 page_table[next_page].bytes_used = remaining_bytes;
1184 bytes_freed = old_bytes_used - remaining_bytes;
1186 /* Free any remaining pages; needs care. */
1188 while ((old_bytes_used == PAGE_BYTES) &&
1189 (page_table[next_page].gen == from_space) &&
1190 (page_table[next_page].allocated == BOXED_PAGE_FLAG) &&
1191 page_table[next_page].large_object &&
1192 (page_table[next_page].first_object_offset ==
1193 -(next_page - first_page)*PAGE_BYTES)) {
1194 /* Checks out OK, free the page. Don't need to bother zeroing
1195 * pages as this should have been done before shrinking the
1196 * object. These pages shouldn't be write-protected as they
1197 * should be zero filled. */
1198 gc_assert(page_table[next_page].write_protected == 0);
1200 old_bytes_used = page_table[next_page].bytes_used;
1201 page_table[next_page].allocated = FREE_PAGE_FLAG;
1202 page_table[next_page].bytes_used = 0;
1203 bytes_freed += old_bytes_used;
1207 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1208 generations[new_space].bytes_allocated += 4*nwords;
1209 bytes_allocated -= bytes_freed;
1211 /* Add the region to the new_areas if requested. */
1212 add_new_area(first_page,0,nwords*4);
1216 /* Get tag of object. */
1217 tag = lowtag_of(object);
1219 /* Allocate space. */
1220 new = gc_quick_alloc_large(nwords*4);
1222 memcpy(new,native_pointer(object),nwords*4);
1224 /* Return Lisp pointer of new object. */
1225 return ((lispobj) new) | tag;
1229 /* to copy unboxed objects */
1231 copy_unboxed_object(lispobj object, int nwords)
1236 gc_assert(is_lisp_pointer(object));
1237 gc_assert(from_space_p(object));
1238 gc_assert((nwords & 0x01) == 0);
1240 /* Get tag of object. */
1241 tag = lowtag_of(object);
1243 /* Allocate space. */
1244 new = gc_quick_alloc_unboxed(nwords*4);
1246 memcpy(new,native_pointer(object),nwords*4);
1248 /* Return Lisp pointer of new object. */
1249 return ((lispobj) new) | tag;
1252 /* to copy large unboxed objects
1254 * If the object is in a large object region then it is simply
1255 * promoted, else it is copied. If it's large enough then it's copied
1256 * to a large object region.
1258 * Bignums and vectors may have shrunk. If the object is not copied
1259 * the space needs to be reclaimed, and the page_tables corrected.
1261 * KLUDGE: There's a lot of cut-and-paste duplication between this
1262 * function and copy_large_object(..). -- WHN 20000619 */
1264 copy_large_unboxed_object(lispobj object, int nwords)
1268 lispobj *source, *dest;
1271 gc_assert(is_lisp_pointer(object));
1272 gc_assert(from_space_p(object));
1273 gc_assert((nwords & 0x01) == 0);
1275 if ((nwords > 1024*1024) && gencgc_verbose)
1276 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*4));
1278 /* Check whether it's a large object. */
1279 first_page = find_page_index((void *)object);
1280 gc_assert(first_page >= 0);
1282 if (page_table[first_page].large_object) {
1283 /* Promote the object. Note: Unboxed objects may have been
1284 * allocated to a BOXED region so it may be necessary to
1285 * change the region to UNBOXED. */
1286 int remaining_bytes;
1291 gc_assert(page_table[first_page].first_object_offset == 0);
1293 next_page = first_page;
1294 remaining_bytes = nwords*4;
1295 while (remaining_bytes > PAGE_BYTES) {
1296 gc_assert(page_table[next_page].gen == from_space);
1297 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1298 || (page_table[next_page].allocated == BOXED_PAGE_FLAG));
1299 gc_assert(page_table[next_page].large_object);
1300 gc_assert(page_table[next_page].first_object_offset==
1301 -PAGE_BYTES*(next_page-first_page));
1302 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1304 page_table[next_page].gen = new_space;
1305 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1306 remaining_bytes -= PAGE_BYTES;
1310 /* Now only one page remains, but the object may have shrunk so
1311 * there may be more unused pages which will be freed. */
1313 /* Object may have shrunk but shouldn't have grown - check. */
1314 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1316 page_table[next_page].gen = new_space;
1317 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1319 /* Adjust the bytes_used. */
1320 old_bytes_used = page_table[next_page].bytes_used;
1321 page_table[next_page].bytes_used = remaining_bytes;
1323 bytes_freed = old_bytes_used - remaining_bytes;
1325 /* Free any remaining pages; needs care. */
1327 while ((old_bytes_used == PAGE_BYTES) &&
1328 (page_table[next_page].gen == from_space) &&
1329 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1330 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
1331 page_table[next_page].large_object &&
1332 (page_table[next_page].first_object_offset ==
1333 -(next_page - first_page)*PAGE_BYTES)) {
1334 /* Checks out OK, free the page. Don't need to both zeroing
1335 * pages as this should have been done before shrinking the
1336 * object. These pages shouldn't be write-protected, even if
1337 * boxed they should be zero filled. */
1338 gc_assert(page_table[next_page].write_protected == 0);
1340 old_bytes_used = page_table[next_page].bytes_used;
1341 page_table[next_page].allocated = FREE_PAGE_FLAG;
1342 page_table[next_page].bytes_used = 0;
1343 bytes_freed += old_bytes_used;
1347 if ((bytes_freed > 0) && gencgc_verbose)
1349 "/copy_large_unboxed bytes_freed=%d\n",
1352 generations[from_space].bytes_allocated -= 4*nwords + bytes_freed;
1353 generations[new_space].bytes_allocated += 4*nwords;
1354 bytes_allocated -= bytes_freed;
1359 /* Get tag of object. */
1360 tag = lowtag_of(object);
1362 /* Allocate space. */
1363 new = gc_quick_alloc_large_unboxed(nwords*4);
1366 source = (lispobj *) native_pointer(object);
1368 /* Copy the object. */
1369 while (nwords > 0) {
1370 dest[0] = source[0];
1371 dest[1] = source[1];
1377 /* Return Lisp pointer of new object. */
1378 return ((lispobj) new) | tag;
1387 * code and code-related objects
1390 static lispobj trans_fun_header(lispobj object);
1391 static lispobj trans_boxed(lispobj object);
1394 /* Scan a x86 compiled code object, looking for possible fixups that
1395 * have been missed after a move.
1397 * Two types of fixups are needed:
1398 * 1. Absolute fixups to within the code object.
1399 * 2. Relative fixups to outside the code object.
1401 * Currently only absolute fixups to the constant vector, or to the
1402 * code area are checked. */
1404 sniff_code_object(struct code *code, unsigned displacement)
1406 int nheader_words, ncode_words, nwords;
1408 void *constants_start_addr, *constants_end_addr;
1409 void *code_start_addr, *code_end_addr;
1410 int fixup_found = 0;
1412 if (!check_code_fixups)
1415 ncode_words = fixnum_value(code->code_size);
1416 nheader_words = HeaderValue(*(lispobj *)code);
1417 nwords = ncode_words + nheader_words;
1419 constants_start_addr = (void *)code + 5*4;
1420 constants_end_addr = (void *)code + nheader_words*4;
1421 code_start_addr = (void *)code + nheader_words*4;
1422 code_end_addr = (void *)code + nwords*4;
1424 /* Work through the unboxed code. */
1425 for (p = code_start_addr; p < code_end_addr; p++) {
1426 void *data = *(void **)p;
1427 unsigned d1 = *((unsigned char *)p - 1);
1428 unsigned d2 = *((unsigned char *)p - 2);
1429 unsigned d3 = *((unsigned char *)p - 3);
1430 unsigned d4 = *((unsigned char *)p - 4);
1432 unsigned d5 = *((unsigned char *)p - 5);
1433 unsigned d6 = *((unsigned char *)p - 6);
1436 /* Check for code references. */
1437 /* Check for a 32 bit word that looks like an absolute
1438 reference to within the code adea of the code object. */
1439 if ((data >= (code_start_addr-displacement))
1440 && (data < (code_end_addr-displacement))) {
1441 /* function header */
1443 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) == (unsigned)code)) {
1444 /* Skip the function header */
1448 /* the case of PUSH imm32 */
1452 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1453 p, d6, d5, d4, d3, d2, d1, data));
1454 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1456 /* the case of MOV [reg-8],imm32 */
1458 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1459 || d2==0x45 || d2==0x46 || d2==0x47)
1463 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1464 p, d6, d5, d4, d3, d2, d1, data));
1465 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1467 /* the case of LEA reg,[disp32] */
1468 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1471 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1472 p, d6, d5, d4, d3, d2, d1, data));
1473 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1477 /* Check for constant references. */
1478 /* Check for a 32 bit word that looks like an absolute
1479 reference to within the constant vector. Constant references
1481 if ((data >= (constants_start_addr-displacement))
1482 && (data < (constants_end_addr-displacement))
1483 && (((unsigned)data & 0x3) == 0)) {
1488 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1489 p, d6, d5, d4, d3, d2, d1, data));
1490 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1493 /* the case of MOV m32,EAX */
1497 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1498 p, d6, d5, d4, d3, d2, d1, data));
1499 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1502 /* the case of CMP m32,imm32 */
1503 if ((d1 == 0x3d) && (d2 == 0x81)) {
1506 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1507 p, d6, d5, d4, d3, d2, d1, data));
1509 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1512 /* Check for a mod=00, r/m=101 byte. */
1513 if ((d1 & 0xc7) == 5) {
1518 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1519 p, d6, d5, d4, d3, d2, d1, data));
1520 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1522 /* the case of CMP reg32,m32 */
1526 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1527 p, d6, d5, d4, d3, d2, d1, data));
1528 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1530 /* the case of MOV m32,reg32 */
1534 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1535 p, d6, d5, d4, d3, d2, d1, data));
1536 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1538 /* the case of MOV reg32,m32 */
1542 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1543 p, d6, d5, d4, d3, d2, d1, data));
1544 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1546 /* the case of LEA reg32,m32 */
1550 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1551 p, d6, d5, d4, d3, d2, d1, data));
1552 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1558 /* If anything was found, print some information on the code
1562 "/compiled code object at %x: header words = %d, code words = %d\n",
1563 code, nheader_words, ncode_words));
1565 "/const start = %x, end = %x\n",
1566 constants_start_addr, constants_end_addr));
1568 "/code start = %x, end = %x\n",
1569 code_start_addr, code_end_addr));
1574 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1576 int nheader_words, ncode_words, nwords;
1577 void *constants_start_addr, *constants_end_addr;
1578 void *code_start_addr, *code_end_addr;
1579 lispobj fixups = NIL;
1580 unsigned displacement = (unsigned)new_code - (unsigned)old_code;
1581 struct vector *fixups_vector;
1583 ncode_words = fixnum_value(new_code->code_size);
1584 nheader_words = HeaderValue(*(lispobj *)new_code);
1585 nwords = ncode_words + nheader_words;
1587 "/compiled code object at %x: header words = %d, code words = %d\n",
1588 new_code, nheader_words, ncode_words)); */
1589 constants_start_addr = (void *)new_code + 5*4;
1590 constants_end_addr = (void *)new_code + nheader_words*4;
1591 code_start_addr = (void *)new_code + nheader_words*4;
1592 code_end_addr = (void *)new_code + nwords*4;
1595 "/const start = %x, end = %x\n",
1596 constants_start_addr,constants_end_addr));
1598 "/code start = %x; end = %x\n",
1599 code_start_addr,code_end_addr));
1602 /* The first constant should be a pointer to the fixups for this
1603 code objects. Check. */
1604 fixups = new_code->constants[0];
1606 /* It will be 0 or the unbound-marker if there are no fixups (as
1607 * will be the case if the code object has been purified, for
1608 * example) and will be an other pointer if it is valid. */
1609 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1610 !is_lisp_pointer(fixups)) {
1611 /* Check for possible errors. */
1612 if (check_code_fixups)
1613 sniff_code_object(new_code, displacement);
1618 fixups_vector = (struct vector *)native_pointer(fixups);
1620 /* Could be pointing to a forwarding pointer. */
1621 /* FIXME is this always in from_space? if so, could replace this code with
1622 * forwarding_pointer_p/forwarding_pointer_value */
1623 if (is_lisp_pointer(fixups) &&
1624 (find_page_index((void*)fixups_vector) != -1) &&
1625 (fixups_vector->header == 0x01)) {
1626 /* If so, then follow it. */
1627 /*SHOW("following pointer to a forwarding pointer");*/
1628 fixups_vector = (struct vector *)native_pointer((lispobj)fixups_vector->length);
1631 /*SHOW("got fixups");*/
1633 if (widetag_of(fixups_vector->header) ==
1634 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG) {
1635 /* Got the fixups for the code block. Now work through the vector,
1636 and apply a fixup at each address. */
1637 int length = fixnum_value(fixups_vector->length);
1639 for (i = 0; i < length; i++) {
1640 unsigned offset = fixups_vector->data[i];
1641 /* Now check the current value of offset. */
1642 unsigned old_value =
1643 *(unsigned *)((unsigned)code_start_addr + offset);
1645 /* If it's within the old_code object then it must be an
1646 * absolute fixup (relative ones are not saved) */
1647 if ((old_value >= (unsigned)old_code)
1648 && (old_value < ((unsigned)old_code + nwords*4)))
1649 /* So add the dispacement. */
1650 *(unsigned *)((unsigned)code_start_addr + offset) =
1651 old_value + displacement;
1653 /* It is outside the old code object so it must be a
1654 * relative fixup (absolute fixups are not saved). So
1655 * subtract the displacement. */
1656 *(unsigned *)((unsigned)code_start_addr + offset) =
1657 old_value - displacement;
1661 /* Check for possible errors. */
1662 if (check_code_fixups) {
1663 sniff_code_object(new_code,displacement);
1669 trans_boxed_large(lispobj object)
1672 unsigned long length;
1674 gc_assert(is_lisp_pointer(object));
1676 header = *((lispobj *) native_pointer(object));
1677 length = HeaderValue(header) + 1;
1678 length = CEILING(length, 2);
1680 return copy_large_object(object, length);
1685 trans_unboxed_large(lispobj object)
1688 unsigned long length;
1691 gc_assert(is_lisp_pointer(object));
1693 header = *((lispobj *) native_pointer(object));
1694 length = HeaderValue(header) + 1;
1695 length = CEILING(length, 2);
1697 return copy_large_unboxed_object(object, length);
1702 * vector-like objects
1706 /* FIXME: What does this mean? */
1707 int gencgc_hash = 1;
1710 scav_vector(lispobj *where, lispobj object)
1712 unsigned int kv_length;
1714 unsigned int length = 0; /* (0 = dummy to stop GCC warning) */
1715 lispobj *hash_table;
1716 lispobj empty_symbol;
1717 unsigned int *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1718 unsigned int *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1719 unsigned int *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1721 unsigned next_vector_length = 0;
1723 /* FIXME: A comment explaining this would be nice. It looks as
1724 * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
1725 * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
1726 if (HeaderValue(object) != subtype_VectorValidHashing)
1730 /* This is set for backward compatibility. FIXME: Do we need
1733 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
1737 kv_length = fixnum_value(where[1]);
1738 kv_vector = where + 2; /* Skip the header and length. */
1739 /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
1741 /* Scavenge element 0, which may be a hash-table structure. */
1742 scavenge(where+2, 1);
1743 if (!is_lisp_pointer(where[2])) {
1744 lose("no pointer at %x in hash table", where[2]);
1746 hash_table = (lispobj *)native_pointer(where[2]);
1747 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1748 if (widetag_of(hash_table[0]) != INSTANCE_HEADER_WIDETAG) {
1749 lose("hash table not instance (%x at %x)", hash_table[0], hash_table);
1752 /* Scavenge element 1, which should be some internal symbol that
1753 * the hash table code reserves for marking empty slots. */
1754 scavenge(where+3, 1);
1755 if (!is_lisp_pointer(where[3])) {
1756 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1758 empty_symbol = where[3];
1759 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1760 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1761 SYMBOL_HEADER_WIDETAG) {
1762 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1763 *(lispobj *)native_pointer(empty_symbol));
1766 /* Scavenge hash table, which will fix the positions of the other
1767 * needed objects. */
1768 scavenge(hash_table, 16);
1770 /* Cross-check the kv_vector. */
1771 if (where != (lispobj *)native_pointer(hash_table[9])) {
1772 lose("hash_table table!=this table %x", hash_table[9]);
1776 weak_p_obj = hash_table[10];
1780 lispobj index_vector_obj = hash_table[13];
1782 if (is_lisp_pointer(index_vector_obj) &&
1783 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1784 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1785 index_vector = ((unsigned int *)native_pointer(index_vector_obj)) + 2;
1786 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1787 length = fixnum_value(((unsigned int *)native_pointer(index_vector_obj))[1]);
1788 /*FSHOW((stderr, "/length = %d\n", length));*/
1790 lose("invalid index_vector %x", index_vector_obj);
1796 lispobj next_vector_obj = hash_table[14];
1798 if (is_lisp_pointer(next_vector_obj) &&
1799 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1800 SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1801 next_vector = ((unsigned int *)native_pointer(next_vector_obj)) + 2;
1802 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1803 next_vector_length = fixnum_value(((unsigned int *)native_pointer(next_vector_obj))[1]);
1804 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1806 lose("invalid next_vector %x", next_vector_obj);
1810 /* maybe hash vector */
1812 /* FIXME: This bare "15" offset should become a symbolic
1813 * expression of some sort. And all the other bare offsets
1814 * too. And the bare "16" in scavenge(hash_table, 16). And
1815 * probably other stuff too. Ugh.. */
1816 lispobj hash_vector_obj = hash_table[15];
1818 if (is_lisp_pointer(hash_vector_obj) &&
1819 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj))
1820 == SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG)) {
1821 hash_vector = ((unsigned int *)native_pointer(hash_vector_obj)) + 2;
1822 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1823 gc_assert(fixnum_value(((unsigned int *)native_pointer(hash_vector_obj))[1])
1824 == next_vector_length);
1827 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1831 /* These lengths could be different as the index_vector can be a
1832 * different length from the others, a larger index_vector could help
1833 * reduce collisions. */
1834 gc_assert(next_vector_length*2 == kv_length);
1836 /* now all set up.. */
1838 /* Work through the KV vector. */
1841 for (i = 1; i < next_vector_length; i++) {
1842 lispobj old_key = kv_vector[2*i];
1843 unsigned int old_index = (old_key & 0x1fffffff)%length;
1845 /* Scavenge the key and value. */
1846 scavenge(&kv_vector[2*i],2);
1848 /* Check whether the key has moved and is EQ based. */
1850 lispobj new_key = kv_vector[2*i];
1851 unsigned int new_index = (new_key & 0x1fffffff)%length;
1853 if ((old_index != new_index) &&
1854 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1855 ((new_key != empty_symbol) ||
1856 (kv_vector[2*i] != empty_symbol))) {
1859 "* EQ key %d moved from %x to %x; index %d to %d\n",
1860 i, old_key, new_key, old_index, new_index));*/
1862 if (index_vector[old_index] != 0) {
1863 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1865 /* Unlink the key from the old_index chain. */
1866 if (index_vector[old_index] == i) {
1867 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1868 index_vector[old_index] = next_vector[i];
1869 /* Link it into the needing rehash chain. */
1870 next_vector[i] = fixnum_value(hash_table[11]);
1871 hash_table[11] = make_fixnum(i);
1874 unsigned prior = index_vector[old_index];
1875 unsigned next = next_vector[prior];
1877 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1880 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1883 next_vector[prior] = next_vector[next];
1884 /* Link it into the needing rehash
1887 fixnum_value(hash_table[11]);
1888 hash_table[11] = make_fixnum(next);
1893 next = next_vector[next];
1901 return (CEILING(kv_length + 2, 2));
1910 /* XX This is a hack adapted from cgc.c. These don't work too
1911 * efficiently with the gencgc as a list of the weak pointers is
1912 * maintained within the objects which causes writes to the pages. A
1913 * limited attempt is made to avoid unnecessary writes, but this needs
1915 #define WEAK_POINTER_NWORDS \
1916 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1919 scav_weak_pointer(lispobj *where, lispobj object)
1921 struct weak_pointer *wp = weak_pointers;
1922 /* Push the weak pointer onto the list of weak pointers.
1923 * Do I have to watch for duplicates? Originally this was
1924 * part of trans_weak_pointer but that didn't work in the
1925 * case where the WP was in a promoted region.
1928 /* Check whether it's already in the list. */
1929 while (wp != NULL) {
1930 if (wp == (struct weak_pointer*)where) {
1936 /* Add it to the start of the list. */
1937 wp = (struct weak_pointer*)where;
1938 if (wp->next != weak_pointers) {
1939 wp->next = weak_pointers;
1941 /*SHOW("avoided write to weak pointer");*/
1946 /* Do not let GC scavenge the value slot of the weak pointer.
1947 * (That is why it is a weak pointer.) */
1949 return WEAK_POINTER_NWORDS;
1953 /* Scan an area looking for an object which encloses the given pointer.
1954 * Return the object start on success or NULL on failure. */
1956 search_space(lispobj *start, size_t words, lispobj *pointer)
1960 lispobj thing = *start;
1962 /* If thing is an immediate then this is a cons. */
1963 if (is_lisp_pointer(thing)
1964 || ((thing & 3) == 0) /* fixnum */
1965 || (widetag_of(thing) == BASE_CHAR_WIDETAG)
1966 || (widetag_of(thing) == UNBOUND_MARKER_WIDETAG))
1969 count = (sizetab[widetag_of(thing)])(start);
1971 /* Check whether the pointer is within this object. */
1972 if ((pointer >= start) && (pointer < (start+count))) {
1974 /*FSHOW((stderr,"/found %x in %x %x\n", pointer, start, thing));*/
1978 /* Round up the count. */
1979 count = CEILING(count,2);
1988 search_read_only_space(lispobj *pointer)
1990 lispobj* start = (lispobj*)READ_ONLY_SPACE_START;
1991 lispobj* end = (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1992 if ((pointer < start) || (pointer >= end))
1994 return (search_space(start, (pointer+2)-start, pointer));
1998 search_static_space(lispobj *pointer)
2000 lispobj* start = (lispobj*)STATIC_SPACE_START;
2001 lispobj* end = (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
2002 if ((pointer < start) || (pointer >= end))
2004 return (search_space(start, (pointer+2)-start, pointer));
2007 /* a faster version for searching the dynamic space. This will work even
2008 * if the object is in a current allocation region. */
2010 search_dynamic_space(lispobj *pointer)
2012 int page_index = find_page_index(pointer);
2015 /* The address may be invalid, so do some checks. */
2016 if ((page_index == -1) ||
2017 (page_table[page_index].allocated == FREE_PAGE_FLAG))
2019 start = (lispobj *)((void *)page_address(page_index)
2020 + page_table[page_index].first_object_offset);
2021 return (search_space(start, (pointer+2)-start, pointer));
2024 /* Is there any possibility that pointer is a valid Lisp object
2025 * reference, and/or something else (e.g. subroutine call return
2026 * address) which should prevent us from moving the referred-to thing?
2027 * This is called from preserve_pointers() */
2029 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2031 lispobj *start_addr;
2033 /* Find the object start address. */
2034 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2038 /* We need to allow raw pointers into Code objects for return
2039 * addresses. This will also pick up pointers to functions in code
2041 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2042 /* XXX could do some further checks here */
2046 /* If it's not a return address then it needs to be a valid Lisp
2048 if (!is_lisp_pointer((lispobj)pointer)) {
2052 /* Check that the object pointed to is consistent with the pointer
2055 switch (lowtag_of((lispobj)pointer)) {
2056 case FUN_POINTER_LOWTAG:
2057 /* Start_addr should be the enclosing code object, or a closure
2059 switch (widetag_of(*start_addr)) {
2060 case CODE_HEADER_WIDETAG:
2061 /* This case is probably caught above. */
2063 case CLOSURE_HEADER_WIDETAG:
2064 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2065 if ((unsigned)pointer !=
2066 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2070 pointer, start_addr, *start_addr));
2078 pointer, start_addr, *start_addr));
2082 case LIST_POINTER_LOWTAG:
2083 if ((unsigned)pointer !=
2084 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2088 pointer, start_addr, *start_addr));
2091 /* Is it plausible cons? */
2092 if ((is_lisp_pointer(start_addr[0])
2093 || ((start_addr[0] & 3) == 0) /* fixnum */
2094 || (widetag_of(start_addr[0]) == BASE_CHAR_WIDETAG)
2095 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2096 && (is_lisp_pointer(start_addr[1])
2097 || ((start_addr[1] & 3) == 0) /* fixnum */
2098 || (widetag_of(start_addr[1]) == BASE_CHAR_WIDETAG)
2099 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2105 pointer, start_addr, *start_addr));
2108 case INSTANCE_POINTER_LOWTAG:
2109 if ((unsigned)pointer !=
2110 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2114 pointer, start_addr, *start_addr));
2117 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2121 pointer, start_addr, *start_addr));
2125 case OTHER_POINTER_LOWTAG:
2126 if ((unsigned)pointer !=
2127 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2131 pointer, start_addr, *start_addr));
2134 /* Is it plausible? Not a cons. XXX should check the headers. */
2135 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2139 pointer, start_addr, *start_addr));
2142 switch (widetag_of(start_addr[0])) {
2143 case UNBOUND_MARKER_WIDETAG:
2144 case BASE_CHAR_WIDETAG:
2148 pointer, start_addr, *start_addr));
2151 /* only pointed to by function pointers? */
2152 case CLOSURE_HEADER_WIDETAG:
2153 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2157 pointer, start_addr, *start_addr));
2160 case INSTANCE_HEADER_WIDETAG:
2164 pointer, start_addr, *start_addr));
2167 /* the valid other immediate pointer objects */
2168 case SIMPLE_VECTOR_WIDETAG:
2170 case COMPLEX_WIDETAG:
2171 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2172 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2174 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2175 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2177 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2178 case COMPLEX_LONG_FLOAT_WIDETAG:
2180 case SIMPLE_ARRAY_WIDETAG:
2181 case COMPLEX_BASE_STRING_WIDETAG:
2182 case COMPLEX_VECTOR_NIL_WIDETAG:
2183 case COMPLEX_BIT_VECTOR_WIDETAG:
2184 case COMPLEX_VECTOR_WIDETAG:
2185 case COMPLEX_ARRAY_WIDETAG:
2186 case VALUE_CELL_HEADER_WIDETAG:
2187 case SYMBOL_HEADER_WIDETAG:
2189 case CODE_HEADER_WIDETAG:
2190 case BIGNUM_WIDETAG:
2191 case SINGLE_FLOAT_WIDETAG:
2192 case DOUBLE_FLOAT_WIDETAG:
2193 #ifdef LONG_FLOAT_WIDETAG
2194 case LONG_FLOAT_WIDETAG:
2196 case SIMPLE_BASE_STRING_WIDETAG:
2197 case SIMPLE_BIT_VECTOR_WIDETAG:
2198 case SIMPLE_ARRAY_NIL_WIDETAG:
2199 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2200 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2201 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2202 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2203 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2204 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2205 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2206 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2207 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2208 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2209 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2211 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2212 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2214 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2215 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2217 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2218 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2220 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2221 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2222 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2223 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2225 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2226 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2228 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2229 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2231 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2232 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2235 case WEAK_POINTER_WIDETAG:
2242 pointer, start_addr, *start_addr));
2250 pointer, start_addr, *start_addr));
2258 /* Adjust large bignum and vector objects. This will adjust the
2259 * allocated region if the size has shrunk, and move unboxed objects
2260 * into unboxed pages. The pages are not promoted here, and the
2261 * promoted region is not added to the new_regions; this is really
2262 * only designed to be called from preserve_pointer(). Shouldn't fail
2263 * if this is missed, just may delay the moving of objects to unboxed
2264 * pages, and the freeing of pages. */
2266 maybe_adjust_large_object(lispobj *where)
2271 int remaining_bytes;
2278 /* Check whether it's a vector or bignum object. */
2279 switch (widetag_of(where[0])) {
2280 case SIMPLE_VECTOR_WIDETAG:
2281 boxed = BOXED_PAGE_FLAG;
2283 case BIGNUM_WIDETAG:
2284 case SIMPLE_BASE_STRING_WIDETAG:
2285 case SIMPLE_BIT_VECTOR_WIDETAG:
2286 case SIMPLE_ARRAY_NIL_WIDETAG:
2287 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2288 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2289 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2290 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2291 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2292 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2293 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2294 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2295 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2296 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2297 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2299 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2300 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2302 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2303 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2305 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2306 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2308 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2309 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2310 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2311 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2313 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2314 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2316 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2317 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2319 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2320 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2322 boxed = UNBOXED_PAGE_FLAG;
2328 /* Find its current size. */
2329 nwords = (sizetab[widetag_of(where[0])])(where);
2331 first_page = find_page_index((void *)where);
2332 gc_assert(first_page >= 0);
2334 /* Note: Any page write-protection must be removed, else a later
2335 * scavenge_newspace may incorrectly not scavenge these pages.
2336 * This would not be necessary if they are added to the new areas,
2337 * but lets do it for them all (they'll probably be written
2340 gc_assert(page_table[first_page].first_object_offset == 0);
2342 next_page = first_page;
2343 remaining_bytes = nwords*4;
2344 while (remaining_bytes > PAGE_BYTES) {
2345 gc_assert(page_table[next_page].gen == from_space);
2346 gc_assert((page_table[next_page].allocated == BOXED_PAGE_FLAG)
2347 || (page_table[next_page].allocated == UNBOXED_PAGE_FLAG));
2348 gc_assert(page_table[next_page].large_object);
2349 gc_assert(page_table[next_page].first_object_offset ==
2350 -PAGE_BYTES*(next_page-first_page));
2351 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2353 page_table[next_page].allocated = boxed;
2355 /* Shouldn't be write-protected at this stage. Essential that the
2357 gc_assert(!page_table[next_page].write_protected);
2358 remaining_bytes -= PAGE_BYTES;
2362 /* Now only one page remains, but the object may have shrunk so
2363 * there may be more unused pages which will be freed. */
2365 /* Object may have shrunk but shouldn't have grown - check. */
2366 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2368 page_table[next_page].allocated = boxed;
2369 gc_assert(page_table[next_page].allocated ==
2370 page_table[first_page].allocated);
2372 /* Adjust the bytes_used. */
2373 old_bytes_used = page_table[next_page].bytes_used;
2374 page_table[next_page].bytes_used = remaining_bytes;
2376 bytes_freed = old_bytes_used - remaining_bytes;
2378 /* Free any remaining pages; needs care. */
2380 while ((old_bytes_used == PAGE_BYTES) &&
2381 (page_table[next_page].gen == from_space) &&
2382 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
2383 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
2384 page_table[next_page].large_object &&
2385 (page_table[next_page].first_object_offset ==
2386 -(next_page - first_page)*PAGE_BYTES)) {
2387 /* It checks out OK, free the page. We don't need to both zeroing
2388 * pages as this should have been done before shrinking the
2389 * object. These pages shouldn't be write protected as they
2390 * should be zero filled. */
2391 gc_assert(page_table[next_page].write_protected == 0);
2393 old_bytes_used = page_table[next_page].bytes_used;
2394 page_table[next_page].allocated = FREE_PAGE_FLAG;
2395 page_table[next_page].bytes_used = 0;
2396 bytes_freed += old_bytes_used;
2400 if ((bytes_freed > 0) && gencgc_verbose) {
2402 "/maybe_adjust_large_object() freed %d\n",
2406 generations[from_space].bytes_allocated -= bytes_freed;
2407 bytes_allocated -= bytes_freed;
2412 /* Take a possible pointer to a Lisp object and mark its page in the
2413 * page_table so that it will not be relocated during a GC.
2415 * This involves locating the page it points to, then backing up to
2416 * the start of its region, then marking all pages dont_move from there
2417 * up to the first page that's not full or has a different generation
2419 * It is assumed that all the page static flags have been cleared at
2420 * the start of a GC.
2422 * It is also assumed that the current gc_alloc() region has been
2423 * flushed and the tables updated. */
2425 preserve_pointer(void *addr)
2427 int addr_page_index = find_page_index(addr);
2430 unsigned region_allocation;
2432 /* quick check 1: Address is quite likely to have been invalid. */
2433 if ((addr_page_index == -1)
2434 || (page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2435 || (page_table[addr_page_index].bytes_used == 0)
2436 || (page_table[addr_page_index].gen != from_space)
2437 /* Skip if already marked dont_move. */
2438 || (page_table[addr_page_index].dont_move != 0))
2440 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2441 /* (Now that we know that addr_page_index is in range, it's
2442 * safe to index into page_table[] with it.) */
2443 region_allocation = page_table[addr_page_index].allocated;
2445 /* quick check 2: Check the offset within the page.
2448 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2451 /* Filter out anything which can't be a pointer to a Lisp object
2452 * (or, as a special case which also requires dont_move, a return
2453 * address referring to something in a CodeObject). This is
2454 * expensive but important, since it vastly reduces the
2455 * probability that random garbage will be bogusly interpreted as
2456 * a pointer which prevents a page from moving. */
2457 if (!(possibly_valid_dynamic_space_pointer(addr)))
2460 /* Find the beginning of the region. Note that there may be
2461 * objects in the region preceding the one that we were passed a
2462 * pointer to: if this is the case, we will write-protect all the
2463 * previous objects' pages too. */
2466 /* I think this'd work just as well, but without the assertions.
2467 * -dan 2004.01.01 */
2469 find_page_index(page_address(addr_page_index)+
2470 page_table[addr_page_index].first_object_offset);
2472 first_page = addr_page_index;
2473 while (page_table[first_page].first_object_offset != 0) {
2475 /* Do some checks. */
2476 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2477 gc_assert(page_table[first_page].gen == from_space);
2478 gc_assert(page_table[first_page].allocated == region_allocation);
2482 /* Adjust any large objects before promotion as they won't be
2483 * copied after promotion. */
2484 if (page_table[first_page].large_object) {
2485 maybe_adjust_large_object(page_address(first_page));
2486 /* If a large object has shrunk then addr may now point to a
2487 * free area in which case it's ignored here. Note it gets
2488 * through the valid pointer test above because the tail looks
2490 if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2491 || (page_table[addr_page_index].bytes_used == 0)
2492 /* Check the offset within the page. */
2493 || (((unsigned)addr & (PAGE_BYTES - 1))
2494 > page_table[addr_page_index].bytes_used)) {
2496 "weird? ignore ptr 0x%x to freed area of large object\n",
2500 /* It may have moved to unboxed pages. */
2501 region_allocation = page_table[first_page].allocated;
2504 /* Now work forward until the end of this contiguous area is found,
2505 * marking all pages as dont_move. */
2506 for (i = first_page; ;i++) {
2507 gc_assert(page_table[i].allocated == region_allocation);
2509 /* Mark the page static. */
2510 page_table[i].dont_move = 1;
2512 /* Move the page to the new_space. XX I'd rather not do this
2513 * but the GC logic is not quite able to copy with the static
2514 * pages remaining in the from space. This also requires the
2515 * generation bytes_allocated counters be updated. */
2516 page_table[i].gen = new_space;
2517 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2518 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2520 /* It is essential that the pages are not write protected as
2521 * they may have pointers into the old-space which need
2522 * scavenging. They shouldn't be write protected at this
2524 gc_assert(!page_table[i].write_protected);
2526 /* Check whether this is the last page in this contiguous block.. */
2527 if ((page_table[i].bytes_used < PAGE_BYTES)
2528 /* ..or it is PAGE_BYTES and is the last in the block */
2529 || (page_table[i+1].allocated == FREE_PAGE_FLAG)
2530 || (page_table[i+1].bytes_used == 0) /* next page free */
2531 || (page_table[i+1].gen != from_space) /* diff. gen */
2532 || (page_table[i+1].first_object_offset == 0))
2536 /* Check that the page is now static. */
2537 gc_assert(page_table[addr_page_index].dont_move != 0);
2540 /* If the given page is not write-protected, then scan it for pointers
2541 * to younger generations or the top temp. generation, if no
2542 * suspicious pointers are found then the page is write-protected.
2544 * Care is taken to check for pointers to the current gc_alloc()
2545 * region if it is a younger generation or the temp. generation. This
2546 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2547 * the gc_alloc_generation does not need to be checked as this is only
2548 * called from scavenge_generation() when the gc_alloc generation is
2549 * younger, so it just checks if there is a pointer to the current
2552 * We return 1 if the page was write-protected, else 0. */
2554 update_page_write_prot(int page)
2556 int gen = page_table[page].gen;
2559 void **page_addr = (void **)page_address(page);
2560 int num_words = page_table[page].bytes_used / 4;
2562 /* Shouldn't be a free page. */
2563 gc_assert(page_table[page].allocated != FREE_PAGE_FLAG);
2564 gc_assert(page_table[page].bytes_used != 0);
2566 /* Skip if it's already write-protected, pinned, or unboxed */
2567 if (page_table[page].write_protected
2568 || page_table[page].dont_move
2569 || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
2572 /* Scan the page for pointers to younger generations or the
2573 * top temp. generation. */
2575 for (j = 0; j < num_words; j++) {
2576 void *ptr = *(page_addr+j);
2577 int index = find_page_index(ptr);
2579 /* Check that it's in the dynamic space */
2581 if (/* Does it point to a younger or the temp. generation? */
2582 ((page_table[index].allocated != FREE_PAGE_FLAG)
2583 && (page_table[index].bytes_used != 0)
2584 && ((page_table[index].gen < gen)
2585 || (page_table[index].gen == NUM_GENERATIONS)))
2587 /* Or does it point within a current gc_alloc() region? */
2588 || ((boxed_region.start_addr <= ptr)
2589 && (ptr <= boxed_region.free_pointer))
2590 || ((unboxed_region.start_addr <= ptr)
2591 && (ptr <= unboxed_region.free_pointer))) {
2598 /* Write-protect the page. */
2599 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2601 os_protect((void *)page_addr,
2603 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2605 /* Note the page as protected in the page tables. */
2606 page_table[page].write_protected = 1;
2612 /* Scavenge a generation.
2614 * This will not resolve all pointers when generation is the new
2615 * space, as new objects may be added which are not checked here - use
2616 * scavenge_newspace generation.
2618 * Write-protected pages should not have any pointers to the
2619 * from_space so do need scavenging; thus write-protected pages are
2620 * not always scavenged. There is some code to check that these pages
2621 * are not written; but to check fully the write-protected pages need
2622 * to be scavenged by disabling the code to skip them.
2624 * Under the current scheme when a generation is GCed the younger
2625 * generations will be empty. So, when a generation is being GCed it
2626 * is only necessary to scavenge the older generations for pointers
2627 * not the younger. So a page that does not have pointers to younger
2628 * generations does not need to be scavenged.
2630 * The write-protection can be used to note pages that don't have
2631 * pointers to younger pages. But pages can be written without having
2632 * pointers to younger generations. After the pages are scavenged here
2633 * they can be scanned for pointers to younger generations and if
2634 * there are none the page can be write-protected.
2636 * One complication is when the newspace is the top temp. generation.
2638 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2639 * that none were written, which they shouldn't be as they should have
2640 * no pointers to younger generations. This breaks down for weak
2641 * pointers as the objects contain a link to the next and are written
2642 * if a weak pointer is scavenged. Still it's a useful check. */
2644 scavenge_generation(int generation)
2651 /* Clear the write_protected_cleared flags on all pages. */
2652 for (i = 0; i < NUM_PAGES; i++)
2653 page_table[i].write_protected_cleared = 0;
2656 for (i = 0; i < last_free_page; i++) {
2657 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2658 && (page_table[i].bytes_used != 0)
2659 && (page_table[i].gen == generation)) {
2661 int write_protected=1;
2663 /* This should be the start of a region */
2664 gc_assert(page_table[i].first_object_offset == 0);
2666 /* Now work forward until the end of the region */
2667 for (last_page = i; ; last_page++) {
2669 write_protected && page_table[last_page].write_protected;
2670 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2671 /* Or it is PAGE_BYTES and is the last in the block */
2672 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2673 || (page_table[last_page+1].bytes_used == 0)
2674 || (page_table[last_page+1].gen != generation)
2675 || (page_table[last_page+1].first_object_offset == 0))
2678 if (!write_protected) {
2679 scavenge(page_address(i), (page_table[last_page].bytes_used
2680 + (last_page-i)*PAGE_BYTES)/4);
2682 /* Now scan the pages and write protect those that
2683 * don't have pointers to younger generations. */
2684 if (enable_page_protection) {
2685 for (j = i; j <= last_page; j++) {
2686 num_wp += update_page_write_prot(j);
2693 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2695 "/write protected %d pages within generation %d\n",
2696 num_wp, generation));
2700 /* Check that none of the write_protected pages in this generation
2701 * have been written to. */
2702 for (i = 0; i < NUM_PAGES; i++) {
2703 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2704 && (page_table[i].bytes_used != 0)
2705 && (page_table[i].gen == generation)
2706 && (page_table[i].write_protected_cleared != 0)) {
2707 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2709 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2710 page_table[i].bytes_used,
2711 page_table[i].first_object_offset,
2712 page_table[i].dont_move));
2713 lose("write to protected page %d in scavenge_generation()", i);
2720 /* Scavenge a newspace generation. As it is scavenged new objects may
2721 * be allocated to it; these will also need to be scavenged. This
2722 * repeats until there are no more objects unscavenged in the
2723 * newspace generation.
2725 * To help improve the efficiency, areas written are recorded by
2726 * gc_alloc() and only these scavenged. Sometimes a little more will be
2727 * scavenged, but this causes no harm. An easy check is done that the
2728 * scavenged bytes equals the number allocated in the previous
2731 * Write-protected pages are not scanned except if they are marked
2732 * dont_move in which case they may have been promoted and still have
2733 * pointers to the from space.
2735 * Write-protected pages could potentially be written by alloc however
2736 * to avoid having to handle re-scavenging of write-protected pages
2737 * gc_alloc() does not write to write-protected pages.
2739 * New areas of objects allocated are recorded alternatively in the two
2740 * new_areas arrays below. */
2741 static struct new_area new_areas_1[NUM_NEW_AREAS];
2742 static struct new_area new_areas_2[NUM_NEW_AREAS];
2744 /* Do one full scan of the new space generation. This is not enough to
2745 * complete the job as new objects may be added to the generation in
2746 * the process which are not scavenged. */
2748 scavenge_newspace_generation_one_scan(int generation)
2753 "/starting one full scan of newspace generation %d\n",
2755 for (i = 0; i < last_free_page; i++) {
2756 /* Note that this skips over open regions when it encounters them. */
2757 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2758 && (page_table[i].bytes_used != 0)
2759 && (page_table[i].gen == generation)
2760 && ((page_table[i].write_protected == 0)
2761 /* (This may be redundant as write_protected is now
2762 * cleared before promotion.) */
2763 || (page_table[i].dont_move == 1))) {
2767 /* The scavenge will start at the first_object_offset of page i.
2769 * We need to find the full extent of this contiguous
2770 * block in case objects span pages.
2772 * Now work forward until the end of this contiguous area
2773 * is found. A small area is preferred as there is a
2774 * better chance of its pages being write-protected. */
2775 for (last_page = i; ;last_page++) {
2776 /* If all pages are write-protected and movable,
2777 * then no need to scavenge */
2778 all_wp=all_wp && page_table[last_page].write_protected &&
2779 !page_table[last_page].dont_move;
2781 /* Check whether this is the last page in this
2782 * contiguous block */
2783 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2784 /* Or it is PAGE_BYTES and is the last in the block */
2785 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2786 || (page_table[last_page+1].bytes_used == 0)
2787 || (page_table[last_page+1].gen != generation)
2788 || (page_table[last_page+1].first_object_offset == 0))
2792 /* Do a limited check for write-protected pages. */
2796 size = (page_table[last_page].bytes_used
2797 + (last_page-i)*PAGE_BYTES
2798 - page_table[i].first_object_offset)/4;
2799 new_areas_ignore_page = last_page;
2801 scavenge(page_address(i) +
2802 page_table[i].first_object_offset,
2810 "/done with one full scan of newspace generation %d\n",
2814 /* Do a complete scavenge of the newspace generation. */
2816 scavenge_newspace_generation(int generation)
2820 /* the new_areas array currently being written to by gc_alloc() */
2821 struct new_area (*current_new_areas)[] = &new_areas_1;
2822 int current_new_areas_index;
2824 /* the new_areas created by the previous scavenge cycle */
2825 struct new_area (*previous_new_areas)[] = NULL;
2826 int previous_new_areas_index;
2828 /* Flush the current regions updating the tables. */
2829 gc_alloc_update_all_page_tables();
2831 /* Turn on the recording of new areas by gc_alloc(). */
2832 new_areas = current_new_areas;
2833 new_areas_index = 0;
2835 /* Don't need to record new areas that get scavenged anyway during
2836 * scavenge_newspace_generation_one_scan. */
2837 record_new_objects = 1;
2839 /* Start with a full scavenge. */
2840 scavenge_newspace_generation_one_scan(generation);
2842 /* Record all new areas now. */
2843 record_new_objects = 2;
2845 /* Flush the current regions updating the tables. */
2846 gc_alloc_update_all_page_tables();
2848 /* Grab new_areas_index. */
2849 current_new_areas_index = new_areas_index;
2852 "The first scan is finished; current_new_areas_index=%d.\n",
2853 current_new_areas_index));*/
2855 while (current_new_areas_index > 0) {
2856 /* Move the current to the previous new areas */
2857 previous_new_areas = current_new_areas;
2858 previous_new_areas_index = current_new_areas_index;
2860 /* Scavenge all the areas in previous new areas. Any new areas
2861 * allocated are saved in current_new_areas. */
2863 /* Allocate an array for current_new_areas; alternating between
2864 * new_areas_1 and 2 */
2865 if (previous_new_areas == &new_areas_1)
2866 current_new_areas = &new_areas_2;
2868 current_new_areas = &new_areas_1;
2870 /* Set up for gc_alloc(). */
2871 new_areas = current_new_areas;
2872 new_areas_index = 0;
2874 /* Check whether previous_new_areas had overflowed. */
2875 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2877 /* New areas of objects allocated have been lost so need to do a
2878 * full scan to be sure! If this becomes a problem try
2879 * increasing NUM_NEW_AREAS. */
2881 SHOW("new_areas overflow, doing full scavenge");
2883 /* Don't need to record new areas that get scavenge anyway
2884 * during scavenge_newspace_generation_one_scan. */
2885 record_new_objects = 1;
2887 scavenge_newspace_generation_one_scan(generation);
2889 /* Record all new areas now. */
2890 record_new_objects = 2;
2892 /* Flush the current regions updating the tables. */
2893 gc_alloc_update_all_page_tables();
2897 /* Work through previous_new_areas. */
2898 for (i = 0; i < previous_new_areas_index; i++) {
2899 /* FIXME: All these bare *4 and /4 should be something
2900 * like BYTES_PER_WORD or WBYTES. */
2901 int page = (*previous_new_areas)[i].page;
2902 int offset = (*previous_new_areas)[i].offset;
2903 int size = (*previous_new_areas)[i].size / 4;
2904 gc_assert((*previous_new_areas)[i].size % 4 == 0);
2905 scavenge(page_address(page)+offset, size);
2908 /* Flush the current regions updating the tables. */
2909 gc_alloc_update_all_page_tables();
2912 current_new_areas_index = new_areas_index;
2915 "The re-scan has finished; current_new_areas_index=%d.\n",
2916 current_new_areas_index));*/
2919 /* Turn off recording of areas allocated by gc_alloc(). */
2920 record_new_objects = 0;
2923 /* Check that none of the write_protected pages in this generation
2924 * have been written to. */
2925 for (i = 0; i < NUM_PAGES; i++) {
2926 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2927 && (page_table[i].bytes_used != 0)
2928 && (page_table[i].gen == generation)
2929 && (page_table[i].write_protected_cleared != 0)
2930 && (page_table[i].dont_move == 0)) {
2931 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2932 i, generation, page_table[i].dont_move);
2938 /* Un-write-protect all the pages in from_space. This is done at the
2939 * start of a GC else there may be many page faults while scavenging
2940 * the newspace (I've seen drive the system time to 99%). These pages
2941 * would need to be unprotected anyway before unmapping in
2942 * free_oldspace; not sure what effect this has on paging.. */
2944 unprotect_oldspace(void)
2948 for (i = 0; i < last_free_page; i++) {
2949 if ((page_table[i].allocated != FREE_PAGE_FLAG)
2950 && (page_table[i].bytes_used != 0)
2951 && (page_table[i].gen == from_space)) {
2954 page_start = (void *)page_address(i);
2956 /* Remove any write-protection. We should be able to rely
2957 * on the write-protect flag to avoid redundant calls. */
2958 if (page_table[i].write_protected) {
2959 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2960 page_table[i].write_protected = 0;
2966 /* Work through all the pages and free any in from_space. This
2967 * assumes that all objects have been copied or promoted to an older
2968 * generation. Bytes_allocated and the generation bytes_allocated
2969 * counter are updated. The number of bytes freed is returned. */
2970 extern void i586_bzero(void *addr, int nbytes);
2974 int bytes_freed = 0;
2975 int first_page, last_page;
2980 /* Find a first page for the next region of pages. */
2981 while ((first_page < last_free_page)
2982 && ((page_table[first_page].allocated == FREE_PAGE_FLAG)
2983 || (page_table[first_page].bytes_used == 0)
2984 || (page_table[first_page].gen != from_space)))
2987 if (first_page >= last_free_page)
2990 /* Find the last page of this region. */
2991 last_page = first_page;
2994 /* Free the page. */
2995 bytes_freed += page_table[last_page].bytes_used;
2996 generations[page_table[last_page].gen].bytes_allocated -=
2997 page_table[last_page].bytes_used;
2998 page_table[last_page].allocated = FREE_PAGE_FLAG;
2999 page_table[last_page].bytes_used = 0;
3001 /* Remove any write-protection. We should be able to rely
3002 * on the write-protect flag to avoid redundant calls. */
3004 void *page_start = (void *)page_address(last_page);
3006 if (page_table[last_page].write_protected) {
3007 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3008 page_table[last_page].write_protected = 0;
3013 while ((last_page < last_free_page)
3014 && (page_table[last_page].allocated != FREE_PAGE_FLAG)
3015 && (page_table[last_page].bytes_used != 0)
3016 && (page_table[last_page].gen == from_space));
3018 /* Zero pages from first_page to (last_page-1).
3020 * FIXME: Why not use os_zero(..) function instead of
3021 * hand-coding this again? (Check other gencgc_unmap_zero
3023 if (gencgc_unmap_zero) {
3024 void *page_start, *addr;
3026 page_start = (void *)page_address(first_page);
3028 os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
3029 addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
3030 if (addr == NULL || addr != page_start) {
3031 /* Is this an error condition? I couldn't really tell from
3032 * the old CMU CL code, which fprintf'ed a message with
3033 * an exclamation point at the end. But I've never seen the
3034 * message, so it must at least be unusual..
3036 * (The same condition is also tested for in gc_free_heap.)
3038 * -- WHN 19991129 */
3039 lose("i586_bzero: page moved, 0x%08x ==> 0x%08x",
3046 page_start = (int *)page_address(first_page);
3047 i586_bzero(page_start, PAGE_BYTES*(last_page-first_page));
3050 first_page = last_page;
3052 } while (first_page < last_free_page);
3054 bytes_allocated -= bytes_freed;
3059 /* Print some information about a pointer at the given address. */
3061 print_ptr(lispobj *addr)
3063 /* If addr is in the dynamic space then out the page information. */
3064 int pi1 = find_page_index((void*)addr);
3067 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3068 (unsigned int) addr,
3070 page_table[pi1].allocated,
3071 page_table[pi1].gen,
3072 page_table[pi1].bytes_used,
3073 page_table[pi1].first_object_offset,
3074 page_table[pi1].dont_move);
3075 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3088 extern int undefined_tramp;
3091 verify_space(lispobj *start, size_t words)
3093 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3094 int is_in_readonly_space =
3095 (READ_ONLY_SPACE_START <= (unsigned)start &&
3096 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3100 lispobj thing = *(lispobj*)start;
3102 if (is_lisp_pointer(thing)) {
3103 int page_index = find_page_index((void*)thing);
3104 int to_readonly_space =
3105 (READ_ONLY_SPACE_START <= thing &&
3106 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3107 int to_static_space =
3108 (STATIC_SPACE_START <= thing &&
3109 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3111 /* Does it point to the dynamic space? */
3112 if (page_index != -1) {
3113 /* If it's within the dynamic space it should point to a used
3114 * page. XX Could check the offset too. */
3115 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
3116 && (page_table[page_index].bytes_used == 0))
3117 lose ("Ptr %x @ %x sees free page.", thing, start);
3118 /* Check that it doesn't point to a forwarding pointer! */
3119 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3120 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3122 /* Check that its not in the RO space as it would then be a
3123 * pointer from the RO to the dynamic space. */
3124 if (is_in_readonly_space) {
3125 lose("ptr to dynamic space %x from RO space %x",
3128 /* Does it point to a plausible object? This check slows
3129 * it down a lot (so it's commented out).
3131 * "a lot" is serious: it ate 50 minutes cpu time on
3132 * my duron 950 before I came back from lunch and
3135 * FIXME: Add a variable to enable this
3138 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3139 lose("ptr %x to invalid object %x", thing, start);
3143 /* Verify that it points to another valid space. */
3144 if (!to_readonly_space && !to_static_space
3145 && (thing != (unsigned)&undefined_tramp)) {
3146 lose("Ptr %x @ %x sees junk.", thing, start);
3150 if (!(fixnump(thing))) {
3152 switch(widetag_of(*start)) {
3155 case SIMPLE_VECTOR_WIDETAG:
3157 case COMPLEX_WIDETAG:
3158 case SIMPLE_ARRAY_WIDETAG:
3159 case COMPLEX_BASE_STRING_WIDETAG:
3160 case COMPLEX_VECTOR_NIL_WIDETAG:
3161 case COMPLEX_BIT_VECTOR_WIDETAG:
3162 case COMPLEX_VECTOR_WIDETAG:
3163 case COMPLEX_ARRAY_WIDETAG:
3164 case CLOSURE_HEADER_WIDETAG:
3165 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3166 case VALUE_CELL_HEADER_WIDETAG:
3167 case SYMBOL_HEADER_WIDETAG:
3168 case BASE_CHAR_WIDETAG:
3169 case UNBOUND_MARKER_WIDETAG:
3170 case INSTANCE_HEADER_WIDETAG:
3175 case CODE_HEADER_WIDETAG:
3177 lispobj object = *start;
3179 int nheader_words, ncode_words, nwords;
3181 struct simple_fun *fheaderp;
3183 code = (struct code *) start;
3185 /* Check that it's not in the dynamic space.
3186 * FIXME: Isn't is supposed to be OK for code
3187 * objects to be in the dynamic space these days? */
3188 if (is_in_dynamic_space
3189 /* It's ok if it's byte compiled code. The trace
3190 * table offset will be a fixnum if it's x86
3191 * compiled code - check.
3193 * FIXME: #^#@@! lack of abstraction here..
3194 * This line can probably go away now that
3195 * there's no byte compiler, but I've got
3196 * too much to worry about right now to try
3197 * to make sure. -- WHN 2001-10-06 */
3198 && fixnump(code->trace_table_offset)
3199 /* Only when enabled */
3200 && verify_dynamic_code_check) {
3202 "/code object at %x in the dynamic space\n",
3206 ncode_words = fixnum_value(code->code_size);
3207 nheader_words = HeaderValue(object);
3208 nwords = ncode_words + nheader_words;
3209 nwords = CEILING(nwords, 2);
3210 /* Scavenge the boxed section of the code data block */
3211 verify_space(start + 1, nheader_words - 1);
3213 /* Scavenge the boxed section of each function
3214 * object in the code data block. */
3215 fheaderl = code->entry_points;
3216 while (fheaderl != NIL) {
3218 (struct simple_fun *) native_pointer(fheaderl);
3219 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3220 verify_space(&fheaderp->name, 1);
3221 verify_space(&fheaderp->arglist, 1);
3222 verify_space(&fheaderp->type, 1);
3223 fheaderl = fheaderp->next;
3229 /* unboxed objects */
3230 case BIGNUM_WIDETAG:
3231 case SINGLE_FLOAT_WIDETAG:
3232 case DOUBLE_FLOAT_WIDETAG:
3233 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3234 case LONG_FLOAT_WIDETAG:
3236 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3237 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3239 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3240 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3242 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3243 case COMPLEX_LONG_FLOAT_WIDETAG:
3245 case SIMPLE_BASE_STRING_WIDETAG:
3246 case SIMPLE_BIT_VECTOR_WIDETAG:
3247 case SIMPLE_ARRAY_NIL_WIDETAG:
3248 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3249 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3250 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3251 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3252 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3253 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3254 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3255 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3256 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3257 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3258 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3260 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3261 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3263 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3264 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3266 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3267 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3269 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3270 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3271 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3272 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3274 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3275 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3277 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3278 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3280 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3281 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3284 case WEAK_POINTER_WIDETAG:
3285 count = (sizetab[widetag_of(*start)])(start);
3301 /* FIXME: It would be nice to make names consistent so that
3302 * foo_size meant size *in* *bytes* instead of size in some
3303 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3304 * Some counts of lispobjs are called foo_count; it might be good
3305 * to grep for all foo_size and rename the appropriate ones to
3307 int read_only_space_size =
3308 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3309 - (lispobj*)READ_ONLY_SPACE_START;
3310 int static_space_size =
3311 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3312 - (lispobj*)STATIC_SPACE_START;
3314 for_each_thread(th) {
3315 int binding_stack_size =
3316 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3317 - (lispobj*)th->binding_stack_start;
3318 verify_space(th->binding_stack_start, binding_stack_size);
3320 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3321 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3325 verify_generation(int generation)
3329 for (i = 0; i < last_free_page; i++) {
3330 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3331 && (page_table[i].bytes_used != 0)
3332 && (page_table[i].gen == generation)) {
3334 int region_allocation = page_table[i].allocated;
3336 /* This should be the start of a contiguous block */
3337 gc_assert(page_table[i].first_object_offset == 0);
3339 /* Need to find the full extent of this contiguous block in case
3340 objects span pages. */
3342 /* Now work forward until the end of this contiguous area is
3344 for (last_page = i; ;last_page++)
3345 /* Check whether this is the last page in this contiguous
3347 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3348 /* Or it is PAGE_BYTES and is the last in the block */
3349 || (page_table[last_page+1].allocated != region_allocation)
3350 || (page_table[last_page+1].bytes_used == 0)
3351 || (page_table[last_page+1].gen != generation)
3352 || (page_table[last_page+1].first_object_offset == 0))
3355 verify_space(page_address(i), (page_table[last_page].bytes_used
3356 + (last_page-i)*PAGE_BYTES)/4);
3362 /* Check that all the free space is zero filled. */
3364 verify_zero_fill(void)
3368 for (page = 0; page < last_free_page; page++) {
3369 if (page_table[page].allocated == FREE_PAGE_FLAG) {
3370 /* The whole page should be zero filled. */
3371 int *start_addr = (int *)page_address(page);
3374 for (i = 0; i < size; i++) {
3375 if (start_addr[i] != 0) {
3376 lose("free page not zero at %x", start_addr + i);
3380 int free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3381 if (free_bytes > 0) {
3382 int *start_addr = (int *)((unsigned)page_address(page)
3383 + page_table[page].bytes_used);
3384 int size = free_bytes / 4;
3386 for (i = 0; i < size; i++) {
3387 if (start_addr[i] != 0) {
3388 lose("free region not zero at %x", start_addr + i);
3396 /* External entry point for verify_zero_fill */
3398 gencgc_verify_zero_fill(void)
3400 /* Flush the alloc regions updating the tables. */
3401 gc_alloc_update_all_page_tables();
3402 SHOW("verifying zero fill");
3407 verify_dynamic_space(void)
3411 for (i = 0; i < NUM_GENERATIONS; i++)
3412 verify_generation(i);
3414 if (gencgc_enable_verify_zero_fill)
3418 /* Write-protect all the dynamic boxed pages in the given generation. */
3420 write_protect_generation_pages(int generation)
3424 gc_assert(generation < NUM_GENERATIONS);
3426 for (i = 0; i < last_free_page; i++)
3427 if ((page_table[i].allocated == BOXED_PAGE_FLAG)
3428 && (page_table[i].bytes_used != 0)
3429 && !page_table[i].dont_move
3430 && (page_table[i].gen == generation)) {
3433 page_start = (void *)page_address(i);
3435 os_protect(page_start,
3437 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3439 /* Note the page as protected in the page tables. */
3440 page_table[i].write_protected = 1;
3443 if (gencgc_verbose > 1) {
3445 "/write protected %d of %d pages in generation %d\n",
3446 count_write_protect_generation_pages(generation),
3447 count_generation_pages(generation),
3452 /* Garbage collect a generation. If raise is 0 then the remains of the
3453 * generation are not raised to the next generation. */
3455 garbage_collect_generation(int generation, int raise)
3457 unsigned long bytes_freed;
3459 unsigned long static_space_size;
3461 gc_assert(generation <= (NUM_GENERATIONS-1));
3463 /* The oldest generation can't be raised. */
3464 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3466 /* Initialize the weak pointer list. */
3467 weak_pointers = NULL;
3469 /* When a generation is not being raised it is transported to a
3470 * temporary generation (NUM_GENERATIONS), and lowered when
3471 * done. Set up this new generation. There should be no pages
3472 * allocated to it yet. */
3474 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3476 /* Set the global src and dest. generations */
3477 from_space = generation;
3479 new_space = generation+1;
3481 new_space = NUM_GENERATIONS;
3483 /* Change to a new space for allocation, resetting the alloc_start_page */
3484 gc_alloc_generation = new_space;
3485 generations[new_space].alloc_start_page = 0;
3486 generations[new_space].alloc_unboxed_start_page = 0;
3487 generations[new_space].alloc_large_start_page = 0;
3488 generations[new_space].alloc_large_unboxed_start_page = 0;
3490 /* Before any pointers are preserved, the dont_move flags on the
3491 * pages need to be cleared. */
3492 for (i = 0; i < last_free_page; i++)
3493 if(page_table[i].gen==from_space)
3494 page_table[i].dont_move = 0;
3496 /* Un-write-protect the old-space pages. This is essential for the
3497 * promoted pages as they may contain pointers into the old-space
3498 * which need to be scavenged. It also helps avoid unnecessary page
3499 * faults as forwarding pointers are written into them. They need to
3500 * be un-protected anyway before unmapping later. */
3501 unprotect_oldspace();
3503 /* Scavenge the stacks' conservative roots. */
3505 /* there are potentially two stacks for each thread: the main
3506 * stack, which may contain Lisp pointers, and the alternate stack.
3507 * We don't ever run Lisp code on the altstack, but it may
3508 * host a sigcontext with lisp objects in it */
3510 /* what we need to do: (1) find the stack pointer for the main
3511 * stack; scavenge it (2) find the interrupt context on the
3512 * alternate stack that might contain lisp values, and scavenge
3515 /* we assume that none of the preceding applies to the thread that
3516 * initiates GC. If you ever call GC from inside an altstack
3517 * handler, you will lose. */
3518 for_each_thread(th) {
3520 void **esp=(void **)-1;
3522 #ifdef LISP_FEATURE_SB_THREAD
3523 if(th==arch_os_get_current_thread()) {
3524 esp = (void **) &raise;
3527 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3528 for(i=free-1;i>=0;i--) {
3529 os_context_t *c=th->interrupt_contexts[i];
3530 esp1 = (void **) *os_context_register_addr(c,reg_ESP);
3531 if(esp1>=th->control_stack_start&& esp1<th->control_stack_end){
3532 if(esp1<esp) esp=esp1;
3533 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3534 preserve_pointer(*ptr);
3540 esp = (void **) &raise;
3542 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3543 preserve_pointer(*ptr);
3548 if (gencgc_verbose > 1) {
3549 int num_dont_move_pages = count_dont_move_pages();
3551 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3552 num_dont_move_pages,
3553 num_dont_move_pages * PAGE_BYTES);
3557 /* Scavenge all the rest of the roots. */
3559 /* Scavenge the Lisp functions of the interrupt handlers, taking
3560 * care to avoid SIG_DFL and SIG_IGN. */
3561 for_each_thread(th) {
3562 struct interrupt_data *data=th->interrupt_data;
3563 for (i = 0; i < NSIG; i++) {
3564 union interrupt_handler handler = data->interrupt_handlers[i];
3565 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3566 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3567 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3571 /* Scavenge the binding stacks. */
3574 for_each_thread(th) {
3575 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3576 th->binding_stack_start;
3577 scavenge((lispobj *) th->binding_stack_start,len);
3578 #ifdef LISP_FEATURE_SB_THREAD
3579 /* do the tls as well */
3580 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3581 (sizeof (struct thread))/(sizeof (lispobj));
3582 scavenge((lispobj *) (th+1),len);
3587 /* The original CMU CL code had scavenge-read-only-space code
3588 * controlled by the Lisp-level variable
3589 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3590 * wasn't documented under what circumstances it was useful or
3591 * safe to turn it on, so it's been turned off in SBCL. If you
3592 * want/need this functionality, and can test and document it,
3593 * please submit a patch. */
3595 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3596 unsigned long read_only_space_size =
3597 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3598 (lispobj*)READ_ONLY_SPACE_START;
3600 "/scavenge read only space: %d bytes\n",
3601 read_only_space_size * sizeof(lispobj)));
3602 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3606 /* Scavenge static space. */
3608 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3609 (lispobj *)STATIC_SPACE_START;
3610 if (gencgc_verbose > 1) {
3612 "/scavenge static space: %d bytes\n",
3613 static_space_size * sizeof(lispobj)));
3615 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3617 /* All generations but the generation being GCed need to be
3618 * scavenged. The new_space generation needs special handling as
3619 * objects may be moved in - it is handled separately below. */
3620 for (i = 0; i < NUM_GENERATIONS; i++) {
3621 if ((i != generation) && (i != new_space)) {
3622 scavenge_generation(i);
3626 /* Finally scavenge the new_space generation. Keep going until no
3627 * more objects are moved into the new generation */
3628 scavenge_newspace_generation(new_space);
3630 /* FIXME: I tried reenabling this check when debugging unrelated
3631 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3632 * Since the current GC code seems to work well, I'm guessing that
3633 * this debugging code is just stale, but I haven't tried to
3634 * figure it out. It should be figured out and then either made to
3635 * work or just deleted. */
3636 #define RESCAN_CHECK 0
3638 /* As a check re-scavenge the newspace once; no new objects should
3641 int old_bytes_allocated = bytes_allocated;
3642 int bytes_allocated;
3644 /* Start with a full scavenge. */
3645 scavenge_newspace_generation_one_scan(new_space);
3647 /* Flush the current regions, updating the tables. */
3648 gc_alloc_update_all_page_tables();
3650 bytes_allocated = bytes_allocated - old_bytes_allocated;
3652 if (bytes_allocated != 0) {
3653 lose("Rescan of new_space allocated %d more bytes.",
3659 scan_weak_pointers();
3661 /* Flush the current regions, updating the tables. */
3662 gc_alloc_update_all_page_tables();
3664 /* Free the pages in oldspace, but not those marked dont_move. */
3665 bytes_freed = free_oldspace();
3667 /* If the GC is not raising the age then lower the generation back
3668 * to its normal generation number */
3670 for (i = 0; i < last_free_page; i++)
3671 if ((page_table[i].bytes_used != 0)
3672 && (page_table[i].gen == NUM_GENERATIONS))
3673 page_table[i].gen = generation;
3674 gc_assert(generations[generation].bytes_allocated == 0);
3675 generations[generation].bytes_allocated =
3676 generations[NUM_GENERATIONS].bytes_allocated;
3677 generations[NUM_GENERATIONS].bytes_allocated = 0;
3680 /* Reset the alloc_start_page for generation. */
3681 generations[generation].alloc_start_page = 0;
3682 generations[generation].alloc_unboxed_start_page = 0;
3683 generations[generation].alloc_large_start_page = 0;
3684 generations[generation].alloc_large_unboxed_start_page = 0;
3686 if (generation >= verify_gens) {
3690 verify_dynamic_space();
3693 /* Set the new gc trigger for the GCed generation. */
3694 generations[generation].gc_trigger =
3695 generations[generation].bytes_allocated
3696 + generations[generation].bytes_consed_between_gc;
3699 generations[generation].num_gc = 0;
3701 ++generations[generation].num_gc;
3704 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3706 update_x86_dynamic_space_free_pointer(void)
3711 for (i = 0; i < NUM_PAGES; i++)
3712 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3713 && (page_table[i].bytes_used != 0))
3716 last_free_page = last_page+1;
3718 SetSymbolValue(ALLOCATION_POINTER,
3719 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3720 return 0; /* dummy value: return something ... */
3723 /* GC all generations newer than last_gen, raising the objects in each
3724 * to the next older generation - we finish when all generations below
3725 * last_gen are empty. Then if last_gen is due for a GC, or if
3726 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3727 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3729 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3730 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3733 collect_garbage(unsigned last_gen)
3740 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3742 if (last_gen > NUM_GENERATIONS) {
3744 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3749 /* Flush the alloc regions updating the tables. */
3750 gc_alloc_update_all_page_tables();
3752 /* Verify the new objects created by Lisp code. */
3753 if (pre_verify_gen_0) {
3754 FSHOW((stderr, "pre-checking generation 0\n"));
3755 verify_generation(0);
3758 if (gencgc_verbose > 1)
3759 print_generation_stats(0);
3762 /* Collect the generation. */
3764 if (gen >= gencgc_oldest_gen_to_gc) {
3765 /* Never raise the oldest generation. */
3770 || (generations[gen].num_gc >= generations[gen].trigger_age);
3773 if (gencgc_verbose > 1) {
3775 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3778 generations[gen].bytes_allocated,
3779 generations[gen].gc_trigger,
3780 generations[gen].num_gc));
3783 /* If an older generation is being filled, then update its
3786 generations[gen+1].cum_sum_bytes_allocated +=
3787 generations[gen+1].bytes_allocated;
3790 garbage_collect_generation(gen, raise);
3792 /* Reset the memory age cum_sum. */
3793 generations[gen].cum_sum_bytes_allocated = 0;
3795 if (gencgc_verbose > 1) {
3796 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3797 print_generation_stats(0);
3801 } while ((gen <= gencgc_oldest_gen_to_gc)
3802 && ((gen < last_gen)
3803 || ((gen <= gencgc_oldest_gen_to_gc)
3805 && (generations[gen].bytes_allocated
3806 > generations[gen].gc_trigger)
3807 && (gen_av_mem_age(gen)
3808 > generations[gen].min_av_mem_age))));
3810 /* Now if gen-1 was raised all generations before gen are empty.
3811 * If it wasn't raised then all generations before gen-1 are empty.
3813 * Now objects within this gen's pages cannot point to younger
3814 * generations unless they are written to. This can be exploited
3815 * by write-protecting the pages of gen; then when younger
3816 * generations are GCed only the pages which have been written
3821 gen_to_wp = gen - 1;
3823 /* There's not much point in WPing pages in generation 0 as it is
3824 * never scavenged (except promoted pages). */
3825 if ((gen_to_wp > 0) && enable_page_protection) {
3826 /* Check that they are all empty. */
3827 for (i = 0; i < gen_to_wp; i++) {
3828 if (generations[i].bytes_allocated)
3829 lose("trying to write-protect gen. %d when gen. %d nonempty",
3832 write_protect_generation_pages(gen_to_wp);
3835 /* Set gc_alloc() back to generation 0. The current regions should
3836 * be flushed after the above GCs. */
3837 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3838 gc_alloc_generation = 0;
3840 update_x86_dynamic_space_free_pointer();
3841 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3843 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3845 SHOW("returning from collect_garbage");
3848 /* This is called by Lisp PURIFY when it is finished. All live objects
3849 * will have been moved to the RO and Static heaps. The dynamic space
3850 * will need a full re-initialization. We don't bother having Lisp
3851 * PURIFY flush the current gc_alloc() region, as the page_tables are
3852 * re-initialized, and every page is zeroed to be sure. */
3858 if (gencgc_verbose > 1)
3859 SHOW("entering gc_free_heap");
3861 for (page = 0; page < NUM_PAGES; page++) {
3862 /* Skip free pages which should already be zero filled. */
3863 if (page_table[page].allocated != FREE_PAGE_FLAG) {
3864 void *page_start, *addr;
3866 /* Mark the page free. The other slots are assumed invalid
3867 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3868 * should not be write-protected -- except that the
3869 * generation is used for the current region but it sets
3871 page_table[page].allocated = FREE_PAGE_FLAG;
3872 page_table[page].bytes_used = 0;
3874 /* Zero the page. */
3875 page_start = (void *)page_address(page);
3877 /* First, remove any write-protection. */
3878 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3879 page_table[page].write_protected = 0;
3881 os_invalidate(page_start,PAGE_BYTES);
3882 addr = os_validate(page_start,PAGE_BYTES);
3883 if (addr == NULL || addr != page_start) {
3884 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3888 } else if (gencgc_zero_check_during_free_heap) {
3889 /* Double-check that the page is zero filled. */
3891 gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
3892 gc_assert(page_table[page].bytes_used == 0);
3893 page_start = (int *)page_address(page);
3894 for (i=0; i<1024; i++) {
3895 if (page_start[i] != 0) {
3896 lose("free region not zero at %x", page_start + i);
3902 bytes_allocated = 0;
3904 /* Initialize the generations. */
3905 for (page = 0; page < NUM_GENERATIONS; page++) {
3906 generations[page].alloc_start_page = 0;
3907 generations[page].alloc_unboxed_start_page = 0;
3908 generations[page].alloc_large_start_page = 0;
3909 generations[page].alloc_large_unboxed_start_page = 0;
3910 generations[page].bytes_allocated = 0;
3911 generations[page].gc_trigger = 2000000;
3912 generations[page].num_gc = 0;
3913 generations[page].cum_sum_bytes_allocated = 0;
3916 if (gencgc_verbose > 1)
3917 print_generation_stats(0);
3919 /* Initialize gc_alloc(). */
3920 gc_alloc_generation = 0;
3922 gc_set_region_empty(&boxed_region);
3923 gc_set_region_empty(&unboxed_region);
3926 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3928 if (verify_after_free_heap) {
3929 /* Check whether purify has left any bad pointers. */
3931 SHOW("checking after free_heap\n");
3942 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
3943 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
3944 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
3946 heap_base = (void*)DYNAMIC_SPACE_START;
3948 /* Initialize each page structure. */
3949 for (i = 0; i < NUM_PAGES; i++) {
3950 /* Initialize all pages as free. */
3951 page_table[i].allocated = FREE_PAGE_FLAG;
3952 page_table[i].bytes_used = 0;
3954 /* Pages are not write-protected at startup. */
3955 page_table[i].write_protected = 0;
3958 bytes_allocated = 0;
3960 /* Initialize the generations.
3962 * FIXME: very similar to code in gc_free_heap(), should be shared */
3963 for (i = 0; i < NUM_GENERATIONS; i++) {
3964 generations[i].alloc_start_page = 0;
3965 generations[i].alloc_unboxed_start_page = 0;
3966 generations[i].alloc_large_start_page = 0;
3967 generations[i].alloc_large_unboxed_start_page = 0;
3968 generations[i].bytes_allocated = 0;
3969 generations[i].gc_trigger = 2000000;
3970 generations[i].num_gc = 0;
3971 generations[i].cum_sum_bytes_allocated = 0;
3972 /* the tune-able parameters */
3973 generations[i].bytes_consed_between_gc = 2000000;
3974 generations[i].trigger_age = 1;
3975 generations[i].min_av_mem_age = 0.75;
3978 /* Initialize gc_alloc. */
3979 gc_alloc_generation = 0;
3980 gc_set_region_empty(&boxed_region);
3981 gc_set_region_empty(&unboxed_region);
3987 /* Pick up the dynamic space from after a core load.
3989 * The ALLOCATION_POINTER points to the end of the dynamic space.
3993 gencgc_pickup_dynamic(void)
3996 int alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
3997 lispobj *prev=(lispobj *)page_address(page);
4000 lispobj *first,*ptr= (lispobj *)page_address(page);
4001 page_table[page].allocated = BOXED_PAGE_FLAG;
4002 page_table[page].gen = 0;
4003 page_table[page].bytes_used = PAGE_BYTES;
4004 page_table[page].large_object = 0;
4006 first=search_space(prev,(ptr+2)-prev,ptr);
4007 if(ptr == first) prev=ptr;
4008 page_table[page].first_object_offset =
4009 (void *)prev - page_address(page);
4011 } while (page_address(page) < alloc_ptr);
4013 generations[0].bytes_allocated = PAGE_BYTES*page;
4014 bytes_allocated = PAGE_BYTES*page;
4020 gc_initialize_pointers(void)
4022 gencgc_pickup_dynamic();
4028 /* alloc(..) is the external interface for memory allocation. It
4029 * allocates to generation 0. It is not called from within the garbage
4030 * collector as it is only external uses that need the check for heap
4031 * size (GC trigger) and to disable the interrupts (interrupts are
4032 * always disabled during a GC).
4034 * The vops that call alloc(..) assume that the returned space is zero-filled.
4035 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4037 * The check for a GC trigger is only performed when the current
4038 * region is full, so in most cases it's not needed. */
4043 struct thread *th=arch_os_get_current_thread();
4044 struct alloc_region *region=
4045 th ? &(th->alloc_region) : &boxed_region;
4047 void *new_free_pointer;
4049 /* Check for alignment allocation problems. */
4050 gc_assert((((unsigned)region->free_pointer & 0x7) == 0)
4051 && ((nbytes & 0x7) == 0));
4053 /* there are a few places in the C code that allocate data in the
4054 * heap before Lisp starts. This is before interrupts are enabled,
4055 * so we don't need to check for pseudo-atomic */
4056 #ifdef LISP_FEATURE_SB_THREAD
4057 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4059 fprintf(stderr, "fatal error in thread 0x%x, pid=%d\n",
4061 __asm__("movl %fs,%0" : "=r" (fs) : );
4062 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4063 debug_get_fs(),th->tls_cookie);
4064 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4067 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4070 /* maybe we can do this quickly ... */
4071 new_free_pointer = region->free_pointer + nbytes;
4072 if (new_free_pointer <= region->end_addr) {
4073 new_obj = (void*)(region->free_pointer);
4074 region->free_pointer = new_free_pointer;
4075 return(new_obj); /* yup */
4078 /* we have to go the long way around, it seems. Check whether
4079 * we should GC in the near future
4081 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4082 /* set things up so that GC happens when we finish the PA
4083 * section. We only do this if there wasn't a pending handler
4084 * already, in case it was a gc. If it wasn't a GC, the next
4085 * allocation will get us back to this point anyway, so no harm done
4087 struct interrupt_data *data=th->interrupt_data;
4088 if(!data->pending_handler)
4089 maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0);
4091 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4096 /* Find the code object for the given pc, or return NULL on failure.
4098 * FIXME: PC shouldn't be lispobj*, should it? Maybe void*? */
4100 component_ptr_from_pc(lispobj *pc)
4102 lispobj *object = NULL;
4104 if ( (object = search_read_only_space(pc)) )
4106 else if ( (object = search_static_space(pc)) )
4109 object = search_dynamic_space(pc);
4111 if (object) /* if we found something */
4112 if (widetag_of(*object) == CODE_HEADER_WIDETAG) /* if it's a code object */
4119 * shared support for the OS-dependent signal handlers which
4120 * catch GENCGC-related write-protect violations
4123 void unhandled_sigmemoryfault(void);
4125 /* Depending on which OS we're running under, different signals might
4126 * be raised for a violation of write protection in the heap. This
4127 * function factors out the common generational GC magic which needs
4128 * to invoked in this case, and should be called from whatever signal
4129 * handler is appropriate for the OS we're running under.
4131 * Return true if this signal is a normal generational GC thing that
4132 * we were able to handle, or false if it was abnormal and control
4133 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4136 gencgc_handle_wp_violation(void* fault_addr)
4138 int page_index = find_page_index(fault_addr);
4140 #if defined QSHOW_SIGNALS
4141 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4142 fault_addr, page_index));
4145 /* Check whether the fault is within the dynamic space. */
4146 if (page_index == (-1)) {
4148 /* It can be helpful to be able to put a breakpoint on this
4149 * case to help diagnose low-level problems. */
4150 unhandled_sigmemoryfault();
4152 /* not within the dynamic space -- not our responsibility */
4156 if (page_table[page_index].write_protected) {
4157 /* Unprotect the page. */
4158 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4159 page_table[page_index].write_protected_cleared = 1;
4160 page_table[page_index].write_protected = 0;
4162 /* The only acceptable reason for this signal on a heap
4163 * access is that GENCGC write-protected the page.
4164 * However, if two CPUs hit a wp page near-simultaneously,
4165 * we had better not have the second one lose here if it
4166 * does this test after the first one has already set wp=0
4168 if(page_table[page_index].write_protected_cleared != 1)
4169 lose("fault in heap page not marked as write-protected");
4171 /* Don't worry, we can handle it. */
4175 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4176 * it's not just a case of the program hitting the write barrier, and
4177 * are about to let Lisp deal with it. It's basically just a
4178 * convenient place to set a gdb breakpoint. */
4180 unhandled_sigmemoryfault()
4183 void gc_alloc_update_all_page_tables(void)
4185 /* Flush the alloc regions updating the tables. */
4188 gc_alloc_update_page_tables(0, &th->alloc_region);
4189 gc_alloc_update_page_tables(1, &unboxed_region);
4190 gc_alloc_update_page_tables(0, &boxed_region);
4193 gc_set_region_empty(struct alloc_region *region)
4195 region->first_page = 0;
4196 region->last_page = -1;
4197 region->start_addr = page_address(0);
4198 region->free_pointer = page_address(0);
4199 region->end_addr = page_address(0);