1 /* "Bag-of-pages" garbage collector for the GNU compiler.
2 Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
23 #include "coretypes.h"
33 #ifdef ENABLE_VALGRIND_CHECKING
34 # ifdef HAVE_VALGRIND_MEMCHECK_H
35 # include <valgrind/memcheck.h>
36 # elif defined HAVE_MEMCHECK_H
37 # include <memcheck.h>
39 # include <valgrind.h>
42 /* Avoid #ifdef:s when we can help it. */
43 #define VALGRIND_DISCARD(x)
46 /* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a
47 file open. Prefer either to valloc. */
49 # undef HAVE_MMAP_DEV_ZERO
51 # include <sys/mman.h>
53 # define MAP_FAILED -1
55 # if !defined (MAP_ANONYMOUS) && defined (MAP_ANON)
56 # define MAP_ANONYMOUS MAP_ANON
62 #ifdef HAVE_MMAP_DEV_ZERO
64 # include <sys/mman.h>
66 # define MAP_FAILED -1
73 #define USING_MALLOC_PAGE_GROUPS
78 This garbage-collecting allocator allocates objects on one of a set
79 of pages. Each page can allocate objects of a single size only;
80 available sizes are powers of two starting at four bytes. The size
81 of an allocation request is rounded up to the next power of two
82 (`order'), and satisfied from the appropriate page.
84 Each page is recorded in a page-entry, which also maintains an
85 in-use bitmap of object positions on the page. This allows the
86 allocation state of a particular object to be flipped without
87 touching the page itself.
89 Each page-entry also has a context depth, which is used to track
90 pushing and popping of allocation contexts. Only objects allocated
91 in the current (highest-numbered) context may be collected.
93 Page entries are arranged in an array of singly-linked lists. The
94 array is indexed by the allocation size, in bits, of the pages on
95 it; i.e. all pages on a list allocate objects of the same size.
96 Pages are ordered on the list such that all non-full pages precede
97 all full pages, with non-full pages arranged in order of decreasing
100 Empty pages (of all orders) are kept on a single page cache list,
101 and are considered first when new pages are required; they are
102 deallocated at the start of the next collection if they haven't
103 been recycled by then. */
105 /* Define GGC_DEBUG_LEVEL to print debugging information.
106 0: No debugging output.
107 1: GC statistics only.
108 2: Page-entry allocations/deallocations as well.
109 3: Object allocations as well.
110 4: Object marks as well. */
111 #define GGC_DEBUG_LEVEL (0)
113 #ifndef HOST_BITS_PER_PTR
114 #define HOST_BITS_PER_PTR HOST_BITS_PER_LONG
118 /* A two-level tree is used to look up the page-entry for a given
119 pointer. Two chunks of the pointer's bits are extracted to index
120 the first and second levels of the tree, as follows:
124 msb +----------------+----+------+------+ lsb
130 The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry
131 pages are aligned on system page boundaries. The next most
132 significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first
133 index values in the lookup table, respectively.
135 For 32-bit architectures and the settings below, there are no
136 leftover bits. For architectures with wider pointers, the lookup
137 tree points to a list of pages, which must be scanned to find the
140 #define PAGE_L1_BITS (8)
141 #define PAGE_L2_BITS (32 - PAGE_L1_BITS - G.lg_pagesize)
142 #define PAGE_L1_SIZE ((size_t) 1 << PAGE_L1_BITS)
143 #define PAGE_L2_SIZE ((size_t) 1 << PAGE_L2_BITS)
145 #define LOOKUP_L1(p) \
146 (((size_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1))
148 #define LOOKUP_L2(p) \
149 (((size_t) (p) >> G.lg_pagesize) & ((1 << PAGE_L2_BITS) - 1))
151 /* The number of objects per allocation page, for objects on a page of
152 the indicated ORDER. */
153 #define OBJECTS_PER_PAGE(ORDER) objects_per_page_table[ORDER]
155 /* The number of objects in P. */
156 #define OBJECTS_IN_PAGE(P) ((P)->bytes / OBJECT_SIZE ((P)->order))
158 /* The size of an object on a page of the indicated ORDER. */
159 #define OBJECT_SIZE(ORDER) object_size_table[ORDER]
161 /* For speed, we avoid doing a general integer divide to locate the
162 offset in the allocation bitmap, by precalculating numbers M, S
163 such that (O * M) >> S == O / Z (modulo 2^32), for any offset O
164 within the page which is evenly divisible by the object size Z. */
165 #define DIV_MULT(ORDER) inverse_table[ORDER].mult
166 #define DIV_SHIFT(ORDER) inverse_table[ORDER].shift
167 #define OFFSET_TO_BIT(OFFSET, ORDER) \
168 (((OFFSET) * DIV_MULT (ORDER)) >> DIV_SHIFT (ORDER))
170 /* The number of extra orders, not corresponding to power-of-two sized
173 #define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table)
175 #define RTL_SIZE(NSLOTS) \
176 (RTX_HDR_SIZE + (NSLOTS) * sizeof (rtunion))
178 #define TREE_EXP_SIZE(OPS) \
179 (sizeof (struct tree_exp) + ((OPS) - 1) * sizeof (tree))
181 /* The Ith entry is the maximum size of an object to be stored in the
182 Ith extra order. Adding a new entry to this array is the *only*
183 thing you need to do to add a new special allocation size. */
185 static const size_t extra_order_size_table[] = {
186 sizeof (struct tree_decl),
187 sizeof (struct tree_list),
189 RTL_SIZE (2), /* MEM, PLUS, etc. */
190 RTL_SIZE (9), /* INSN, CALL_INSN, JUMP_INSN */
193 /* The total number of orders. */
195 #define NUM_ORDERS (HOST_BITS_PER_PTR + NUM_EXTRA_ORDERS)
197 /* We use this structure to determine the alignment required for
198 allocations. For power-of-two sized allocations, that's not a
199 problem, but it does matter for odd-sized allocations. */
201 struct max_alignment {
209 /* The biggest alignment required. */
211 #define MAX_ALIGNMENT (offsetof (struct max_alignment, u))
213 /* Compute the smallest nonnegative number which when added to X gives
216 #define ROUND_UP_VALUE(x, f) ((f) - 1 - ((f) - 1 + (x)) % (f))
218 /* Compute the smallest multiple of F that is >= X. */
220 #define ROUND_UP(x, f) (CEIL (x, f) * (f))
222 /* The Ith entry is the number of objects on a page or order I. */
224 static unsigned objects_per_page_table[NUM_ORDERS];
226 /* The Ith entry is the size of an object on a page of order I. */
228 static size_t object_size_table[NUM_ORDERS];
230 /* The Ith entry is a pair of numbers (mult, shift) such that
231 ((k * mult) >> shift) mod 2^32 == (k / OBJECT_SIZE(I)) mod 2^32,
232 for all k evenly divisible by OBJECT_SIZE(I). */
239 inverse_table[NUM_ORDERS];
241 /* A page_entry records the status of an allocation page. This
242 structure is dynamically sized to fit the bitmap in_use_p. */
243 typedef struct page_entry
245 /* The next page-entry with objects of the same size, or NULL if
246 this is the last page-entry. */
247 struct page_entry *next;
249 /* The number of bytes allocated. (This will always be a multiple
250 of the host system page size.) */
253 /* The address at which the memory is allocated. */
256 #ifdef USING_MALLOC_PAGE_GROUPS
257 /* Back pointer to the page group this page came from. */
258 struct page_group *group;
261 /* This is the index in the by_depth varray where this page table
263 unsigned long index_by_depth;
265 /* Context depth of this page. */
266 unsigned short context_depth;
268 /* The number of free objects remaining on this page. */
269 unsigned short num_free_objects;
271 /* A likely candidate for the bit position of a free object for the
272 next allocation from this page. */
273 unsigned short next_bit_hint;
275 /* The lg of size of objects allocated from this page. */
278 /* A bit vector indicating whether or not objects are in use. The
279 Nth bit is one if the Nth object on this page is allocated. This
280 array is dynamically sized. */
281 unsigned long in_use_p[1];
284 #ifdef USING_MALLOC_PAGE_GROUPS
285 /* A page_group describes a large allocation from malloc, from which
286 we parcel out aligned pages. */
287 typedef struct page_group
289 /* A linked list of all extant page groups. */
290 struct page_group *next;
292 /* The address we received from malloc. */
295 /* The size of the block. */
298 /* A bitmask of pages in use. */
303 #if HOST_BITS_PER_PTR <= 32
305 /* On 32-bit hosts, we use a two level page table, as pictured above. */
306 typedef page_entry **page_table[PAGE_L1_SIZE];
310 /* On 64-bit hosts, we use the same two level page tables plus a linked
311 list that disambiguates the top 32-bits. There will almost always be
312 exactly one entry in the list. */
313 typedef struct page_table_chain
315 struct page_table_chain *next;
317 page_entry **table[PAGE_L1_SIZE];
322 /* The rest of the global variables. */
323 static struct globals
325 /* The Nth element in this array is a page with objects of size 2^N.
326 If there are any pages with free objects, they will be at the
327 head of the list. NULL if there are no page-entries for this
329 page_entry *pages[NUM_ORDERS];
331 /* The Nth element in this array is the last page with objects of
332 size 2^N. NULL if there are no page-entries for this object
334 page_entry *page_tails[NUM_ORDERS];
336 /* Lookup table for associating allocation pages with object addresses. */
339 /* The system's page size. */
343 /* Bytes currently allocated. */
346 /* Bytes currently allocated at the end of the last collection. */
347 size_t allocated_last_gc;
349 /* Total amount of memory mapped. */
352 /* Bit N set if any allocations have been done at context depth N. */
353 unsigned long context_depth_allocations;
355 /* Bit N set if any collections have been done at context depth N. */
356 unsigned long context_depth_collections;
358 /* The current depth in the context stack. */
359 unsigned short context_depth;
361 /* A file descriptor open to /dev/zero for reading. */
362 #if defined (HAVE_MMAP_DEV_ZERO)
366 /* A cache of free system pages. */
367 page_entry *free_pages;
369 #ifdef USING_MALLOC_PAGE_GROUPS
370 page_group *page_groups;
373 /* The file descriptor for debugging output. */
376 /* Current number of elements in use in depth below. */
377 unsigned int depth_in_use;
379 /* Maximum number of elements that can be used before resizing. */
380 unsigned int depth_max;
382 /* Each element of this arry is an index in by_depth where the given
383 depth starts. This structure is indexed by that given depth we
384 are interested in. */
387 /* Current number of elements in use in by_depth below. */
388 unsigned int by_depth_in_use;
390 /* Maximum number of elements that can be used before resizing. */
391 unsigned int by_depth_max;
393 /* Each element of this array is a pointer to a page_entry, all
394 page_entries can be found in here by increasing depth.
395 index_by_depth in the page_entry is the index into this data
396 structure where that page_entry can be found. This is used to
397 speed up finding all page_entries at a particular depth. */
398 page_entry **by_depth;
400 /* Each element is a pointer to the saved in_use_p bits, if any,
401 zero otherwise. We allocate them all together, to enable a
402 better runtime data access pattern. */
403 unsigned long **save_in_use;
405 #ifdef GATHER_STATISTICS
408 /* Total memory allocated with ggc_alloc */
409 unsigned long long total_allocated;
410 /* Total overhead for memory to be allocated with ggc_alloc */
411 unsigned long long total_overhead;
413 /* Total allocations and overhead for sizes less than 32, 64 and 128.
414 These sizes are interesting because they are typical cache line
417 unsigned long long total_allocated_under32;
418 unsigned long long total_overhead_under32;
420 unsigned long long total_allocated_under64;
421 unsigned long long total_overhead_under64;
423 unsigned long long total_allocated_under128;
424 unsigned long long total_overhead_under128;
426 /* The overhead for each of the allocation orders. */
427 unsigned long long total_overhead_per_order[NUM_ORDERS];
432 /* The size in bytes required to maintain a bitmap for the objects
434 #define BITMAP_SIZE(Num_objects) \
435 (CEIL ((Num_objects), HOST_BITS_PER_LONG) * sizeof(long))
437 /* Allocate pages in chunks of this size, to throttle calls to memory
438 allocation routines. The first page is used, the rest go onto the
439 free list. This cannot be larger than HOST_BITS_PER_INT for the
440 in_use bitmask for page_group. */
441 #define GGC_QUIRE_SIZE 16
443 /* Initial guess as to how many page table entries we might need. */
444 #define INITIAL_PTE_COUNT 128
446 static int ggc_allocated_p (const void *);
447 static page_entry *lookup_page_table_entry (const void *);
448 static void set_page_table_entry (void *, page_entry *);
450 static char *alloc_anon (char *, size_t);
452 #ifdef USING_MALLOC_PAGE_GROUPS
453 static size_t page_group_index (char *, char *);
454 static void set_page_group_in_use (page_group *, char *);
455 static void clear_page_group_in_use (page_group *, char *);
457 static struct page_entry * alloc_page (unsigned);
458 static void free_page (struct page_entry *);
459 static void release_pages (void);
460 static void clear_marks (void);
461 static void sweep_pages (void);
462 static void ggc_recalculate_in_use_p (page_entry *);
463 static void compute_inverse (unsigned);
464 static inline void adjust_depth (void);
465 static void move_ptes_to_front (int, int);
467 #ifdef ENABLE_GC_CHECKING
468 static void poison_pages (void);
471 void debug_print_page_list (int);
472 static void push_depth (unsigned int);
473 static void push_by_depth (page_entry *, unsigned long *);
474 struct alloc_zone *rtl_zone = NULL;
475 struct alloc_zone *tree_zone = NULL;
476 struct alloc_zone *garbage_zone = NULL;
478 /* Push an entry onto G.depth. */
481 push_depth (unsigned int i)
483 if (G.depth_in_use >= G.depth_max)
486 G.depth = xrealloc (G.depth, G.depth_max * sizeof (unsigned int));
488 G.depth[G.depth_in_use++] = i;
491 /* Push an entry onto G.by_depth and G.save_in_use. */
494 push_by_depth (page_entry *p, unsigned long *s)
496 if (G.by_depth_in_use >= G.by_depth_max)
499 G.by_depth = xrealloc (G.by_depth,
500 G.by_depth_max * sizeof (page_entry *));
501 G.save_in_use = xrealloc (G.save_in_use,
502 G.by_depth_max * sizeof (unsigned long *));
504 G.by_depth[G.by_depth_in_use] = p;
505 G.save_in_use[G.by_depth_in_use++] = s;
508 #if (GCC_VERSION < 3001)
509 #define prefetch(X) ((void) X)
511 #define prefetch(X) __builtin_prefetch (X)
514 #define save_in_use_p_i(__i) \
516 #define save_in_use_p(__p) \
517 (save_in_use_p_i (__p->index_by_depth))
519 /* Returns nonzero if P was allocated in GC'able memory. */
522 ggc_allocated_p (const void *p)
527 #if HOST_BITS_PER_PTR <= 32
530 page_table table = G.lookup;
531 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
536 if (table->high_bits == high_bits)
540 base = &table->table[0];
543 /* Extract the level 1 and 2 indices. */
547 return base[L1] && base[L1][L2];
550 /* Traverse the page table and find the entry for a page.
551 Die (probably) if the object wasn't allocated via GC. */
553 static inline page_entry *
554 lookup_page_table_entry (const void *p)
559 #if HOST_BITS_PER_PTR <= 32
562 page_table table = G.lookup;
563 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
564 while (table->high_bits != high_bits)
566 base = &table->table[0];
569 /* Extract the level 1 and 2 indices. */
576 /* Set the page table entry for a page. */
579 set_page_table_entry (void *p, page_entry *entry)
584 #if HOST_BITS_PER_PTR <= 32
588 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
589 for (table = G.lookup; table; table = table->next)
590 if (table->high_bits == high_bits)
593 /* Not found -- allocate a new table. */
594 table = xcalloc (1, sizeof(*table));
595 table->next = G.lookup;
596 table->high_bits = high_bits;
599 base = &table->table[0];
602 /* Extract the level 1 and 2 indices. */
606 if (base[L1] == NULL)
607 base[L1] = xcalloc (PAGE_L2_SIZE, sizeof (page_entry *));
609 base[L1][L2] = entry;
612 /* Prints the page-entry for object size ORDER, for debugging. */
615 debug_print_page_list (int order)
618 printf ("Head=%p, Tail=%p:\n", (void *) G.pages[order],
619 (void *) G.page_tails[order]);
623 printf ("%p(%1d|%3d) -> ", (void *) p, p->context_depth,
624 p->num_free_objects);
632 /* Allocate SIZE bytes of anonymous memory, preferably near PREF,
633 (if non-null). The ifdef structure here is intended to cause a
634 compile error unless exactly one of the HAVE_* is defined. */
637 alloc_anon (char *pref ATTRIBUTE_UNUSED, size_t size)
639 #ifdef HAVE_MMAP_ANON
640 char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
641 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
643 #ifdef HAVE_MMAP_DEV_ZERO
644 char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
645 MAP_PRIVATE, G.dev_zero_fd, 0);
648 if (page == (char *) MAP_FAILED)
650 perror ("virtual memory exhausted");
651 exit (FATAL_EXIT_CODE);
654 /* Remember that we allocated this memory. */
655 G.bytes_mapped += size;
657 /* Pretend we don't have access to the allocated pages. We'll enable
658 access to smaller pieces of the area in ggc_alloc. Discard the
659 handle to avoid handle leak. */
660 VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (page, size));
665 #ifdef USING_MALLOC_PAGE_GROUPS
666 /* Compute the index for this page into the page group. */
669 page_group_index (char *allocation, char *page)
671 return (size_t) (page - allocation) >> G.lg_pagesize;
674 /* Set and clear the in_use bit for this page in the page group. */
677 set_page_group_in_use (page_group *group, char *page)
679 group->in_use |= 1 << page_group_index (group->allocation, page);
683 clear_page_group_in_use (page_group *group, char *page)
685 group->in_use &= ~(1 << page_group_index (group->allocation, page));
689 /* Allocate a new page for allocating objects of size 2^ORDER,
690 and return an entry for it. The entry is not added to the
691 appropriate page_table list. */
693 static inline struct page_entry *
694 alloc_page (unsigned order)
696 struct page_entry *entry, *p, **pp;
700 size_t page_entry_size;
702 #ifdef USING_MALLOC_PAGE_GROUPS
706 num_objects = OBJECTS_PER_PAGE (order);
707 bitmap_size = BITMAP_SIZE (num_objects + 1);
708 page_entry_size = sizeof (page_entry) - sizeof (long) + bitmap_size;
709 entry_size = num_objects * OBJECT_SIZE (order);
710 if (entry_size < G.pagesize)
711 entry_size = G.pagesize;
716 /* Check the list of free pages for one we can use. */
717 for (pp = &G.free_pages, p = *pp; p; pp = &p->next, p = *pp)
718 if (p->bytes == entry_size)
723 /* Recycle the allocated memory from this page ... */
727 #ifdef USING_MALLOC_PAGE_GROUPS
731 /* ... and, if possible, the page entry itself. */
732 if (p->order == order)
735 memset (entry, 0, page_entry_size);
741 else if (entry_size == G.pagesize)
743 /* We want just one page. Allocate a bunch of them and put the
744 extras on the freelist. (Can only do this optimization with
745 mmap for backing store.) */
746 struct page_entry *e, *f = G.free_pages;
749 page = alloc_anon (NULL, G.pagesize * GGC_QUIRE_SIZE);
751 /* This loop counts down so that the chain will be in ascending
753 for (i = GGC_QUIRE_SIZE - 1; i >= 1; i--)
755 e = xcalloc (1, page_entry_size);
757 e->bytes = G.pagesize;
758 e->page = page + (i << G.lg_pagesize);
766 page = alloc_anon (NULL, entry_size);
768 #ifdef USING_MALLOC_PAGE_GROUPS
771 /* Allocate a large block of memory and serve out the aligned
772 pages therein. This results in much less memory wastage
773 than the traditional implementation of valloc. */
775 char *allocation, *a, *enda;
776 size_t alloc_size, head_slop, tail_slop;
777 int multiple_pages = (entry_size == G.pagesize);
780 alloc_size = GGC_QUIRE_SIZE * G.pagesize;
782 alloc_size = entry_size + G.pagesize - 1;
783 allocation = xmalloc (alloc_size);
785 page = (char *) (((size_t) allocation + G.pagesize - 1) & -G.pagesize);
786 head_slop = page - allocation;
788 tail_slop = ((size_t) allocation + alloc_size) & (G.pagesize - 1);
790 tail_slop = alloc_size - entry_size - head_slop;
791 enda = allocation + alloc_size - tail_slop;
793 /* We allocated N pages, which are likely not aligned, leaving
794 us with N-1 usable pages. We plan to place the page_group
795 structure somewhere in the slop. */
796 if (head_slop >= sizeof (page_group))
797 group = (page_group *)page - 1;
800 /* We magically got an aligned allocation. Too bad, we have
801 to waste a page anyway. */
805 tail_slop += G.pagesize;
807 if (tail_slop < sizeof (page_group))
809 group = (page_group *)enda;
810 tail_slop -= sizeof (page_group);
813 /* Remember that we allocated this memory. */
814 group->next = G.page_groups;
815 group->allocation = allocation;
816 group->alloc_size = alloc_size;
818 G.page_groups = group;
819 G.bytes_mapped += alloc_size;
821 /* If we allocated multiple pages, put the rest on the free list. */
824 struct page_entry *e, *f = G.free_pages;
825 for (a = enda - G.pagesize; a != page; a -= G.pagesize)
827 e = xcalloc (1, page_entry_size);
829 e->bytes = G.pagesize;
841 entry = xcalloc (1, page_entry_size);
843 entry->bytes = entry_size;
845 entry->context_depth = G.context_depth;
846 entry->order = order;
847 entry->num_free_objects = num_objects;
848 entry->next_bit_hint = 1;
850 G.context_depth_allocations |= (unsigned long)1 << G.context_depth;
852 #ifdef USING_MALLOC_PAGE_GROUPS
853 entry->group = group;
854 set_page_group_in_use (group, page);
857 /* Set the one-past-the-end in-use bit. This acts as a sentry as we
858 increment the hint. */
859 entry->in_use_p[num_objects / HOST_BITS_PER_LONG]
860 = (unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG);
862 set_page_table_entry (page, entry);
864 if (GGC_DEBUG_LEVEL >= 2)
865 fprintf (G.debug_file,
866 "Allocating page at %p, object size=%lu, data %p-%p\n",
867 (void *) entry, (unsigned long) OBJECT_SIZE (order), page,
868 page + entry_size - 1);
873 /* Adjust the size of G.depth so that no index greater than the one
874 used by the top of the G.by_depth is used. */
881 if (G.by_depth_in_use)
883 top = G.by_depth[G.by_depth_in_use-1];
885 /* Peel back indices in depth that index into by_depth, so that
886 as new elements are added to by_depth, we note the indices
887 of those elements, if they are for new context depths. */
888 while (G.depth_in_use > (size_t)top->context_depth+1)
893 /* For a page that is no longer needed, put it on the free page list. */
896 free_page (page_entry *entry)
898 if (GGC_DEBUG_LEVEL >= 2)
899 fprintf (G.debug_file,
900 "Deallocating page at %p, data %p-%p\n", (void *) entry,
901 entry->page, entry->page + entry->bytes - 1);
903 /* Mark the page as inaccessible. Discard the handle to avoid handle
905 VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (entry->page, entry->bytes));
907 set_page_table_entry (entry->page, NULL);
909 #ifdef USING_MALLOC_PAGE_GROUPS
910 clear_page_group_in_use (entry->group, entry->page);
913 if (G.by_depth_in_use > 1)
915 page_entry *top = G.by_depth[G.by_depth_in_use-1];
917 /* If they are at the same depth, put top element into freed
919 if (entry->context_depth == top->context_depth)
921 int i = entry->index_by_depth;
923 G.save_in_use[i] = G.save_in_use[G.by_depth_in_use-1];
924 top->index_by_depth = i;
928 /* We cannot free a page from a context deeper than the
937 entry->next = G.free_pages;
938 G.free_pages = entry;
941 /* Release the free page cache to the system. */
947 page_entry *p, *next;
951 /* Gather up adjacent pages so they are unmapped together. */
962 while (p && p->page == start + len)
971 G.bytes_mapped -= len;
976 #ifdef USING_MALLOC_PAGE_GROUPS
980 /* Remove all pages from free page groups from the list. */
982 while ((p = *pp) != NULL)
983 if (p->group->in_use == 0)
991 /* Remove all free page groups, and release the storage. */
993 while ((g = *gp) != NULL)
997 G.bytes_mapped -= g->alloc_size;
998 free (g->allocation);
1005 /* This table provides a fast way to determine ceil(log_2(size)) for
1006 allocation requests. The minimum allocation size is eight bytes. */
1008 static unsigned char size_lookup[257] =
1010 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4,
1011 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
1012 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1013 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1014 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1015 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1016 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1017 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1018 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1019 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1020 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1021 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1022 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1023 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1024 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1025 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1029 /* Typed allocation function. Does nothing special in this collector. */
1032 ggc_alloc_typed (enum gt_types_enum type ATTRIBUTE_UNUSED, size_t size)
1034 return ggc_alloc (size);
1037 /* Zone allocation function. Does nothing special in this collector. */
1040 ggc_alloc_zone (size_t size, struct alloc_zone *zone ATTRIBUTE_UNUSED)
1042 return ggc_alloc (size);
1045 /* Allocate a chunk of memory of SIZE bytes. Its contents are undefined. */
1048 ggc_alloc (size_t size)
1050 unsigned order, word, bit, object_offset;
1051 struct page_entry *entry;
1055 order = size_lookup[size];
1059 while (size > OBJECT_SIZE (order))
1063 /* If there are non-full pages for this size allocation, they are at
1064 the head of the list. */
1065 entry = G.pages[order];
1067 /* If there is no page for this object size, or all pages in this
1068 context are full, allocate a new page. */
1069 if (entry == NULL || entry->num_free_objects == 0)
1071 struct page_entry *new_entry;
1072 new_entry = alloc_page (order);
1074 new_entry->index_by_depth = G.by_depth_in_use;
1075 push_by_depth (new_entry, 0);
1077 /* We can skip context depths, if we do, make sure we go all the
1078 way to the new depth. */
1079 while (new_entry->context_depth >= G.depth_in_use)
1080 push_depth (G.by_depth_in_use-1);
1082 /* If this is the only entry, it's also the tail. */
1084 G.page_tails[order] = new_entry;
1086 /* Put new pages at the head of the page list. */
1087 new_entry->next = entry;
1089 G.pages[order] = new_entry;
1091 /* For a new page, we know the word and bit positions (in the
1092 in_use bitmap) of the first available object -- they're zero. */
1093 new_entry->next_bit_hint = 1;
1100 /* First try to use the hint left from the previous allocation
1101 to locate a clear bit in the in-use bitmap. We've made sure
1102 that the one-past-the-end bit is always set, so if the hint
1103 has run over, this test will fail. */
1104 unsigned hint = entry->next_bit_hint;
1105 word = hint / HOST_BITS_PER_LONG;
1106 bit = hint % HOST_BITS_PER_LONG;
1108 /* If the hint didn't work, scan the bitmap from the beginning. */
1109 if ((entry->in_use_p[word] >> bit) & 1)
1112 while (~entry->in_use_p[word] == 0)
1114 while ((entry->in_use_p[word] >> bit) & 1)
1116 hint = word * HOST_BITS_PER_LONG + bit;
1119 /* Next time, try the next bit. */
1120 entry->next_bit_hint = hint + 1;
1122 object_offset = hint * OBJECT_SIZE (order);
1125 /* Set the in-use bit. */
1126 entry->in_use_p[word] |= ((unsigned long) 1 << bit);
1128 /* Keep a running total of the number of free objects. If this page
1129 fills up, we may have to move it to the end of the list if the
1130 next page isn't full. If the next page is full, all subsequent
1131 pages are full, so there's no need to move it. */
1132 if (--entry->num_free_objects == 0
1133 && entry->next != NULL
1134 && entry->next->num_free_objects > 0)
1136 G.pages[order] = entry->next;
1138 G.page_tails[order]->next = entry;
1139 G.page_tails[order] = entry;
1142 /* Calculate the object's address. */
1143 result = entry->page + object_offset;
1145 #ifdef ENABLE_GC_CHECKING
1146 /* Keep poisoning-by-writing-0xaf the object, in an attempt to keep the
1147 exact same semantics in presence of memory bugs, regardless of
1148 ENABLE_VALGRIND_CHECKING. We override this request below. Drop the
1149 handle to avoid handle leak. */
1150 VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, OBJECT_SIZE (order)));
1152 /* `Poison' the entire allocated object, including any padding at
1154 memset (result, 0xaf, OBJECT_SIZE (order));
1156 /* Make the bytes after the end of the object unaccessible. Discard the
1157 handle to avoid handle leak. */
1158 VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS ((char *) result + size,
1159 OBJECT_SIZE (order) - size));
1162 /* Tell Valgrind that the memory is there, but its content isn't
1163 defined. The bytes at the end of the object are still marked
1165 VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (result, size));
1167 /* Keep track of how many bytes are being allocated. This
1168 information is used in deciding when to collect. */
1169 G.allocated += OBJECT_SIZE (order);
1171 #ifdef GATHER_STATISTICS
1173 G.stats.total_overhead += OBJECT_SIZE (order) - size;
1174 G.stats.total_overhead_per_order[order] += OBJECT_SIZE (order) - size;
1175 G.stats.total_allocated += OBJECT_SIZE(order);
1178 G.stats.total_overhead_under32 += OBJECT_SIZE (order) - size;
1179 G.stats.total_allocated_under32 += OBJECT_SIZE(order);
1183 G.stats.total_overhead_under64 += OBJECT_SIZE (order) - size;
1184 G.stats.total_allocated_under64 += OBJECT_SIZE(order);
1188 G.stats.total_overhead_under128 += OBJECT_SIZE (order) - size;
1189 G.stats.total_allocated_under128 += OBJECT_SIZE(order);
1195 if (GGC_DEBUG_LEVEL >= 3)
1196 fprintf (G.debug_file,
1197 "Allocating object, requested size=%lu, actual=%lu at %p on %p\n",
1198 (unsigned long) size, (unsigned long) OBJECT_SIZE (order), result,
1204 /* If P is not marked, marks it and return false. Otherwise return true.
1205 P must have been allocated by the GC allocator; it mustn't point to
1206 static objects, stack variables, or memory allocated with malloc. */
1209 ggc_set_mark (const void *p)
1215 /* Look up the page on which the object is alloced. If the object
1216 wasn't allocated by the collector, we'll probably die. */
1217 entry = lookup_page_table_entry (p);
1218 #ifdef ENABLE_CHECKING
1223 /* Calculate the index of the object on the page; this is its bit
1224 position in the in_use_p bitmap. */
1225 bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
1226 word = bit / HOST_BITS_PER_LONG;
1227 mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
1229 /* If the bit was previously set, skip it. */
1230 if (entry->in_use_p[word] & mask)
1233 /* Otherwise set it, and decrement the free object count. */
1234 entry->in_use_p[word] |= mask;
1235 entry->num_free_objects -= 1;
1237 if (GGC_DEBUG_LEVEL >= 4)
1238 fprintf (G.debug_file, "Marking %p\n", p);
1243 /* Return 1 if P has been marked, zero otherwise.
1244 P must have been allocated by the GC allocator; it mustn't point to
1245 static objects, stack variables, or memory allocated with malloc. */
1248 ggc_marked_p (const void *p)
1254 /* Look up the page on which the object is alloced. If the object
1255 wasn't allocated by the collector, we'll probably die. */
1256 entry = lookup_page_table_entry (p);
1257 #ifdef ENABLE_CHECKING
1262 /* Calculate the index of the object on the page; this is its bit
1263 position in the in_use_p bitmap. */
1264 bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
1265 word = bit / HOST_BITS_PER_LONG;
1266 mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
1268 return (entry->in_use_p[word] & mask) != 0;
1271 /* Return the size of the gc-able object P. */
1274 ggc_get_size (const void *p)
1276 page_entry *pe = lookup_page_table_entry (p);
1277 return OBJECT_SIZE (pe->order);
1280 /* Subroutine of init_ggc which computes the pair of numbers used to
1281 perform division by OBJECT_SIZE (order) and fills in inverse_table[].
1283 This algorithm is taken from Granlund and Montgomery's paper
1284 "Division by Invariant Integers using Multiplication"
1285 (Proc. SIGPLAN PLDI, 1994), section 9 (Exact division by
1289 compute_inverse (unsigned order)
1294 size = OBJECT_SIZE (order);
1296 while (size % 2 == 0)
1303 while (inv * size != 1)
1304 inv = inv * (2 - inv*size);
1306 DIV_MULT (order) = inv;
1307 DIV_SHIFT (order) = e;
1310 /* Initialize the ggc-mmap allocator. */
1316 G.pagesize = getpagesize();
1317 G.lg_pagesize = exact_log2 (G.pagesize);
1319 #ifdef HAVE_MMAP_DEV_ZERO
1320 G.dev_zero_fd = open ("/dev/zero", O_RDONLY);
1321 if (G.dev_zero_fd == -1)
1322 internal_error ("open /dev/zero: %m");
1326 G.debug_file = fopen ("ggc-mmap.debug", "w");
1328 G.debug_file = stdout;
1332 /* StunOS has an amazing off-by-one error for the first mmap allocation
1333 after fiddling with RLIMIT_STACK. The result, as hard as it is to
1334 believe, is an unaligned page allocation, which would cause us to
1335 hork badly if we tried to use it. */
1337 char *p = alloc_anon (NULL, G.pagesize);
1338 struct page_entry *e;
1339 if ((size_t)p & (G.pagesize - 1))
1341 /* How losing. Discard this one and try another. If we still
1342 can't get something useful, give up. */
1344 p = alloc_anon (NULL, G.pagesize);
1345 if ((size_t)p & (G.pagesize - 1))
1349 /* We have a good page, might as well hold onto it... */
1350 e = xcalloc (1, sizeof (struct page_entry));
1351 e->bytes = G.pagesize;
1353 e->next = G.free_pages;
1358 /* Initialize the object size table. */
1359 for (order = 0; order < HOST_BITS_PER_PTR; ++order)
1360 object_size_table[order] = (size_t) 1 << order;
1361 for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order)
1363 size_t s = extra_order_size_table[order - HOST_BITS_PER_PTR];
1365 /* If S is not a multiple of the MAX_ALIGNMENT, then round it up
1366 so that we're sure of getting aligned memory. */
1367 s = ROUND_UP (s, MAX_ALIGNMENT);
1368 object_size_table[order] = s;
1371 /* Initialize the objects-per-page and inverse tables. */
1372 for (order = 0; order < NUM_ORDERS; ++order)
1374 objects_per_page_table[order] = G.pagesize / OBJECT_SIZE (order);
1375 if (objects_per_page_table[order] == 0)
1376 objects_per_page_table[order] = 1;
1377 compute_inverse (order);
1380 /* Reset the size_lookup array to put appropriately sized objects in
1381 the special orders. All objects bigger than the previous power
1382 of two, but no greater than the special size, should go in the
1384 for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order)
1389 o = size_lookup[OBJECT_SIZE (order)];
1390 for (i = OBJECT_SIZE (order); size_lookup [i] == o; --i)
1391 size_lookup[i] = order;
1396 G.depth = xmalloc (G.depth_max * sizeof (unsigned int));
1398 G.by_depth_in_use = 0;
1399 G.by_depth_max = INITIAL_PTE_COUNT;
1400 G.by_depth = xmalloc (G.by_depth_max * sizeof (page_entry *));
1401 G.save_in_use = xmalloc (G.by_depth_max * sizeof (unsigned long *));
1404 /* Start a new GGC zone. */
1407 new_ggc_zone (const char *name ATTRIBUTE_UNUSED)
1412 /* Destroy a GGC zone. */
1414 destroy_ggc_zone (struct alloc_zone *zone ATTRIBUTE_UNUSED)
1418 /* Increment the `GC context'. Objects allocated in an outer context
1419 are never freed, eliminating the need to register their roots. */
1422 ggc_push_context (void)
1427 if (G.context_depth >= HOST_BITS_PER_LONG)
1431 /* Merge the SAVE_IN_USE_P and IN_USE_P arrays in P so that IN_USE_P
1432 reflects reality. Recalculate NUM_FREE_OBJECTS as well. */
1435 ggc_recalculate_in_use_p (page_entry *p)
1440 /* Because the past-the-end bit in in_use_p is always set, we
1441 pretend there is one additional object. */
1442 num_objects = OBJECTS_IN_PAGE (p) + 1;
1444 /* Reset the free object count. */
1445 p->num_free_objects = num_objects;
1447 /* Combine the IN_USE_P and SAVE_IN_USE_P arrays. */
1449 i < CEIL (BITMAP_SIZE (num_objects),
1450 sizeof (*p->in_use_p));
1455 /* Something is in use if it is marked, or if it was in use in a
1456 context further down the context stack. */
1457 p->in_use_p[i] |= save_in_use_p (p)[i];
1459 /* Decrement the free object count for every object allocated. */
1460 for (j = p->in_use_p[i]; j; j >>= 1)
1461 p->num_free_objects -= (j & 1);
1464 if (p->num_free_objects >= num_objects)
1468 /* Decrement the `GC context'. All objects allocated since the
1469 previous ggc_push_context are migrated to the outer context. */
1472 ggc_pop_context (void)
1474 unsigned long omask;
1475 unsigned int depth, i, e;
1476 #ifdef ENABLE_CHECKING
1480 depth = --G.context_depth;
1481 omask = (unsigned long)1 << (depth + 1);
1483 if (!((G.context_depth_allocations | G.context_depth_collections) & omask))
1486 G.context_depth_allocations |= (G.context_depth_allocations & omask) >> 1;
1487 G.context_depth_allocations &= omask - 1;
1488 G.context_depth_collections &= omask - 1;
1490 /* The G.depth array is shortened so that the last index is the
1491 context_depth of the top element of by_depth. */
1492 if (depth+1 < G.depth_in_use)
1493 e = G.depth[depth+1];
1495 e = G.by_depth_in_use;
1497 /* We might not have any PTEs of depth depth. */
1498 if (depth < G.depth_in_use)
1501 /* First we go through all the pages at depth depth to
1502 recalculate the in use bits. */
1503 for (i = G.depth[depth]; i < e; ++i)
1507 #ifdef ENABLE_CHECKING
1510 /* Check that all of the pages really are at the depth that
1512 if (p->context_depth != depth)
1514 if (p->index_by_depth != i)
1518 prefetch (&save_in_use_p_i (i+8));
1519 prefetch (&save_in_use_p_i (i+16));
1520 if (save_in_use_p_i (i))
1523 ggc_recalculate_in_use_p (p);
1524 free (save_in_use_p_i (i));
1525 save_in_use_p_i (i) = 0;
1530 /* Then, we reset all page_entries with a depth greater than depth
1532 for (i = e; i < G.by_depth_in_use; ++i)
1534 page_entry *p = G.by_depth[i];
1536 /* Check that all of the pages really are at the depth we
1538 #ifdef ENABLE_CHECKING
1539 if (p->context_depth <= depth)
1541 if (p->index_by_depth != i)
1544 p->context_depth = depth;
1549 #ifdef ENABLE_CHECKING
1550 for (order = 2; order < NUM_ORDERS; order++)
1554 for (p = G.pages[order]; p != NULL; p = p->next)
1556 if (p->context_depth > depth)
1558 else if (p->context_depth == depth && save_in_use_p (p))
1565 /* Unmark all objects. */
1572 for (order = 2; order < NUM_ORDERS; order++)
1576 for (p = G.pages[order]; p != NULL; p = p->next)
1578 size_t num_objects = OBJECTS_IN_PAGE (p);
1579 size_t bitmap_size = BITMAP_SIZE (num_objects + 1);
1581 #ifdef ENABLE_CHECKING
1582 /* The data should be page-aligned. */
1583 if ((size_t) p->page & (G.pagesize - 1))
1587 /* Pages that aren't in the topmost context are not collected;
1588 nevertheless, we need their in-use bit vectors to store GC
1589 marks. So, back them up first. */
1590 if (p->context_depth < G.context_depth)
1592 if (! save_in_use_p (p))
1593 save_in_use_p (p) = xmalloc (bitmap_size);
1594 memcpy (save_in_use_p (p), p->in_use_p, bitmap_size);
1597 /* Reset reset the number of free objects and clear the
1598 in-use bits. These will be adjusted by mark_obj. */
1599 p->num_free_objects = num_objects;
1600 memset (p->in_use_p, 0, bitmap_size);
1602 /* Make sure the one-past-the-end bit is always set. */
1603 p->in_use_p[num_objects / HOST_BITS_PER_LONG]
1604 = ((unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG));
1609 /* Free all empty pages. Partially empty pages need no attention
1610 because the `mark' bit doubles as an `unused' bit. */
1617 for (order = 2; order < NUM_ORDERS; order++)
1619 /* The last page-entry to consider, regardless of entries
1620 placed at the end of the list. */
1621 page_entry * const last = G.page_tails[order];
1624 size_t live_objects;
1625 page_entry *p, *previous;
1635 page_entry *next = p->next;
1637 /* Loop until all entries have been examined. */
1640 num_objects = OBJECTS_IN_PAGE (p);
1642 /* Add all live objects on this page to the count of
1643 allocated memory. */
1644 live_objects = num_objects - p->num_free_objects;
1646 G.allocated += OBJECT_SIZE (order) * live_objects;
1648 /* Only objects on pages in the topmost context should get
1650 if (p->context_depth < G.context_depth)
1653 /* Remove the page if it's empty. */
1654 else if (live_objects == 0)
1657 G.pages[order] = next;
1659 previous->next = next;
1661 /* Are we removing the last element? */
1662 if (p == G.page_tails[order])
1663 G.page_tails[order] = previous;
1668 /* If the page is full, move it to the end. */
1669 else if (p->num_free_objects == 0)
1671 /* Don't move it if it's already at the end. */
1672 if (p != G.page_tails[order])
1674 /* Move p to the end of the list. */
1676 G.page_tails[order]->next = p;
1678 /* Update the tail pointer... */
1679 G.page_tails[order] = p;
1681 /* ... and the head pointer, if necessary. */
1683 G.pages[order] = next;
1685 previous->next = next;
1690 /* If we've fallen through to here, it's a page in the
1691 topmost context that is neither full nor empty. Such a
1692 page must precede pages at lesser context depth in the
1693 list, so move it to the head. */
1694 else if (p != G.pages[order])
1696 previous->next = p->next;
1697 p->next = G.pages[order];
1699 /* Are we moving the last element? */
1700 if (G.page_tails[order] == p)
1701 G.page_tails[order] = previous;
1710 /* Now, restore the in_use_p vectors for any pages from contexts
1711 other than the current one. */
1712 for (p = G.pages[order]; p; p = p->next)
1713 if (p->context_depth != G.context_depth)
1714 ggc_recalculate_in_use_p (p);
1718 #ifdef ENABLE_GC_CHECKING
1719 /* Clobber all free objects. */
1726 for (order = 2; order < NUM_ORDERS; order++)
1728 size_t size = OBJECT_SIZE (order);
1731 for (p = G.pages[order]; p != NULL; p = p->next)
1736 if (p->context_depth != G.context_depth)
1737 /* Since we don't do any collection for pages in pushed
1738 contexts, there's no need to do any poisoning. And
1739 besides, the IN_USE_P array isn't valid until we pop
1743 num_objects = OBJECTS_IN_PAGE (p);
1744 for (i = 0; i < num_objects; i++)
1747 word = i / HOST_BITS_PER_LONG;
1748 bit = i % HOST_BITS_PER_LONG;
1749 if (((p->in_use_p[word] >> bit) & 1) == 0)
1751 char *object = p->page + i * size;
1753 /* Keep poison-by-write when we expect to use Valgrind,
1754 so the exact same memory semantics is kept, in case
1755 there are memory errors. We override this request
1757 VALGRIND_DISCARD (VALGRIND_MAKE_WRITABLE (object, size));
1758 memset (object, 0xa5, size);
1760 /* Drop the handle to avoid handle leak. */
1761 VALGRIND_DISCARD (VALGRIND_MAKE_NOACCESS (object, size));
1769 /* Top level mark-and-sweep routine. */
1774 /* Avoid frequent unnecessary work by skipping collection if the
1775 total allocations haven't expanded much since the last
1777 float allocated_last_gc =
1778 MAX (G.allocated_last_gc, (size_t)PARAM_VALUE (GGC_MIN_HEAPSIZE) * 1024);
1780 float min_expand = allocated_last_gc * PARAM_VALUE (GGC_MIN_EXPAND) / 100;
1782 if (G.allocated < allocated_last_gc + min_expand)
1785 timevar_push (TV_GC);
1787 fprintf (stderr, " {GC %luk -> ", (unsigned long) G.allocated / 1024);
1789 /* Zero the total allocated bytes. This will be recalculated in the
1793 /* Release the pages we freed the last time we collected, but didn't
1794 reuse in the interim. */
1797 /* Indicate that we've seen collections at this context depth. */
1798 G.context_depth_collections = ((unsigned long)1 << (G.context_depth + 1)) - 1;
1803 #ifdef ENABLE_GC_CHECKING
1809 G.allocated_last_gc = G.allocated;
1811 timevar_pop (TV_GC);
1814 fprintf (stderr, "%luk}", (unsigned long) G.allocated / 1024);
1817 /* Print allocation statistics. */
1818 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
1820 : ((x) < 1024*1024*10 \
1822 : (x) / (1024*1024))))
1823 #define LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
1826 ggc_print_statistics (void)
1828 struct ggc_statistics stats;
1830 size_t total_overhead = 0;
1832 /* Clear the statistics. */
1833 memset (&stats, 0, sizeof (stats));
1835 /* Make sure collection will really occur. */
1836 G.allocated_last_gc = 0;
1838 /* Collect and print the statistics common across collectors. */
1839 ggc_print_common_statistics (stderr, &stats);
1841 /* Release free pages so that we will not count the bytes allocated
1842 there as part of the total allocated memory. */
1845 /* Collect some information about the various sizes of
1847 fprintf (stderr, "%-5s %10s %10s %10s\n",
1848 "Size", "Allocated", "Used", "Overhead");
1849 for (i = 0; i < NUM_ORDERS; ++i)
1856 /* Skip empty entries. */
1860 overhead = allocated = in_use = 0;
1862 /* Figure out the total number of bytes allocated for objects of
1863 this size, and how many of them are actually in use. Also figure
1864 out how much memory the page table is using. */
1865 for (p = G.pages[i]; p; p = p->next)
1867 allocated += p->bytes;
1869 (OBJECTS_IN_PAGE (p) - p->num_free_objects) * OBJECT_SIZE (i);
1871 overhead += (sizeof (page_entry) - sizeof (long)
1872 + BITMAP_SIZE (OBJECTS_IN_PAGE (p) + 1));
1874 fprintf (stderr, "%-5lu %10lu%c %10lu%c %10lu%c\n",
1875 (unsigned long) OBJECT_SIZE (i),
1876 SCALE (allocated), LABEL (allocated),
1877 SCALE (in_use), LABEL (in_use),
1878 SCALE (overhead), LABEL (overhead));
1879 total_overhead += overhead;
1881 fprintf (stderr, "%-5s %10lu%c %10lu%c %10lu%c\n", "Total",
1882 SCALE (G.bytes_mapped), LABEL (G.bytes_mapped),
1883 SCALE (G.allocated), LABEL(G.allocated),
1884 SCALE (total_overhead), LABEL (total_overhead));
1886 #ifdef GATHER_STATISTICS
1888 fprintf (stderr, "Total Overhead: %10lld\n",
1889 G.stats.total_overhead);
1890 fprintf (stderr, "Total Allocated: %10lld\n",
1891 G.stats.total_allocated);
1893 fprintf (stderr, "Total Overhead under 32B: %10lld\n",
1894 G.stats.total_overhead_under32);
1895 fprintf (stderr, "Total Allocated under 32B: %10lld\n",
1896 G.stats.total_allocated_under32);
1897 fprintf (stderr, "Total Overhead under 64B: %10lld\n",
1898 G.stats.total_overhead_under64);
1899 fprintf (stderr, "Total Allocated under 64B: %10lld\n",
1900 G.stats.total_allocated_under64);
1901 fprintf (stderr, "Total Overhead under 128B: %10lld\n",
1902 G.stats.total_overhead_under128);
1903 fprintf (stderr, "Total Allocated under 128B: %10lld\n",
1904 G.stats.total_allocated_under128);
1906 for (i = 0; i < NUM_ORDERS; i++)
1907 if (G.stats.total_overhead_per_order[i])
1908 fprintf (stderr, "Total Overhead page size %7d: %10lld\n",
1909 OBJECT_SIZE (i), G.stats.total_overhead_per_order[i]);
1916 struct ggc_pch_ondisk
1918 unsigned totals[NUM_ORDERS];
1920 size_t base[NUM_ORDERS];
1921 size_t written[NUM_ORDERS];
1924 struct ggc_pch_data *
1927 return xcalloc (sizeof (struct ggc_pch_data), 1);
1931 ggc_pch_count_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
1932 size_t size, bool is_string ATTRIBUTE_UNUSED)
1937 order = size_lookup[size];
1941 while (size > OBJECT_SIZE (order))
1945 d->d.totals[order]++;
1949 ggc_pch_total_size (struct ggc_pch_data *d)
1954 for (i = 0; i < NUM_ORDERS; i++)
1955 a += ROUND_UP (d->d.totals[i] * OBJECT_SIZE (i), G.pagesize);
1960 ggc_pch_this_base (struct ggc_pch_data *d, void *base)
1962 size_t a = (size_t) base;
1965 for (i = 0; i < NUM_ORDERS; i++)
1968 a += ROUND_UP (d->d.totals[i] * OBJECT_SIZE (i), G.pagesize);
1974 ggc_pch_alloc_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
1975 size_t size, bool is_string ATTRIBUTE_UNUSED)
1981 order = size_lookup[size];
1985 while (size > OBJECT_SIZE (order))
1989 result = (char *) d->base[order];
1990 d->base[order] += OBJECT_SIZE (order);
1995 ggc_pch_prepare_write (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
1996 FILE *f ATTRIBUTE_UNUSED)
1998 /* Nothing to do. */
2002 ggc_pch_write_object (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
2003 FILE *f, void *x, void *newx ATTRIBUTE_UNUSED,
2004 size_t size, bool is_string ATTRIBUTE_UNUSED)
2007 static const char emptyBytes[256];
2010 order = size_lookup[size];
2014 while (size > OBJECT_SIZE (order))
2018 if (fwrite (x, size, 1, f) != 1)
2019 fatal_error ("can't write PCH file: %m");
2021 /* If SIZE is not the same as OBJECT_SIZE(order), then we need to pad the
2022 object out to OBJECT_SIZE(order). This happens for strings. */
2024 if (size != OBJECT_SIZE (order))
2026 unsigned padding = OBJECT_SIZE(order) - size;
2028 /* To speed small writes, we use a nulled-out array that's larger
2029 than most padding requests as the source for our null bytes. This
2030 permits us to do the padding with fwrite() rather than fseek(), and
2031 limits the chance the the OS may try to flush any outstanding
2033 if (padding <= sizeof(emptyBytes))
2035 if (fwrite (emptyBytes, 1, padding, f) != padding)
2036 fatal_error ("can't write PCH file");
2040 /* Larger than our buffer? Just default to fseek. */
2041 if (fseek (f, padding, SEEK_CUR) != 0)
2042 fatal_error ("can't write PCH file");
2046 d->written[order]++;
2047 if (d->written[order] == d->d.totals[order]
2048 && fseek (f, ROUND_UP_VALUE (d->d.totals[order] * OBJECT_SIZE (order),
2051 fatal_error ("can't write PCH file: %m");
2055 ggc_pch_finish (struct ggc_pch_data *d, FILE *f)
2057 if (fwrite (&d->d, sizeof (d->d), 1, f) != 1)
2058 fatal_error ("can't write PCH file: %m");
2062 /* Move the PCH PTE entries just added to the end of by_depth, to the
2066 move_ptes_to_front (int count_old_page_tables, int count_new_page_tables)
2070 /* First, we swap the new entries to the front of the varrays. */
2071 page_entry **new_by_depth;
2072 unsigned long **new_save_in_use;
2074 new_by_depth = xmalloc (G.by_depth_max * sizeof (page_entry *));
2075 new_save_in_use = xmalloc (G.by_depth_max * sizeof (unsigned long *));
2077 memcpy (&new_by_depth[0],
2078 &G.by_depth[count_old_page_tables],
2079 count_new_page_tables * sizeof (void *));
2080 memcpy (&new_by_depth[count_new_page_tables],
2082 count_old_page_tables * sizeof (void *));
2083 memcpy (&new_save_in_use[0],
2084 &G.save_in_use[count_old_page_tables],
2085 count_new_page_tables * sizeof (void *));
2086 memcpy (&new_save_in_use[count_new_page_tables],
2088 count_old_page_tables * sizeof (void *));
2091 free (G.save_in_use);
2093 G.by_depth = new_by_depth;
2094 G.save_in_use = new_save_in_use;
2096 /* Now update all the index_by_depth fields. */
2097 for (i = G.by_depth_in_use; i > 0; --i)
2099 page_entry *p = G.by_depth[i-1];
2100 p->index_by_depth = i-1;
2103 /* And last, we update the depth pointers in G.depth. The first
2104 entry is already 0, and context 0 entries always start at index
2105 0, so there is nothing to update in the first slot. We need a
2106 second slot, only if we have old ptes, and if we do, they start
2107 at index count_new_page_tables. */
2108 if (count_old_page_tables)
2109 push_depth (count_new_page_tables);
2113 ggc_pch_read (FILE *f, void *addr)
2115 struct ggc_pch_ondisk d;
2118 unsigned long count_old_page_tables;
2119 unsigned long count_new_page_tables;
2121 count_old_page_tables = G.by_depth_in_use;
2123 /* We've just read in a PCH file. So, every object that used to be
2124 allocated is now free. */
2126 #ifdef ENABLE_GC_CHECKING
2130 /* No object read from a PCH file should ever be freed. So, set the
2131 context depth to 1, and set the depth of all the currently-allocated
2132 pages to be 1 too. PCH pages will have depth 0. */
2133 if (G.context_depth != 0)
2135 G.context_depth = 1;
2136 for (i = 0; i < NUM_ORDERS; i++)
2139 for (p = G.pages[i]; p != NULL; p = p->next)
2140 p->context_depth = G.context_depth;
2143 /* Allocate the appropriate page-table entries for the pages read from
2145 if (fread (&d, sizeof (d), 1, f) != 1)
2146 fatal_error ("can't read PCH file: %m");
2148 for (i = 0; i < NUM_ORDERS; i++)
2150 struct page_entry *entry;
2156 if (d.totals[i] == 0)
2159 bytes = ROUND_UP (d.totals[i] * OBJECT_SIZE (i), G.pagesize);
2160 num_objs = bytes / OBJECT_SIZE (i);
2161 entry = xcalloc (1, (sizeof (struct page_entry)
2163 + BITMAP_SIZE (num_objs + 1)));
2164 entry->bytes = bytes;
2166 entry->context_depth = 0;
2168 entry->num_free_objects = 0;
2172 j + HOST_BITS_PER_LONG <= num_objs + 1;
2173 j += HOST_BITS_PER_LONG)
2174 entry->in_use_p[j / HOST_BITS_PER_LONG] = -1;
2175 for (; j < num_objs + 1; j++)
2176 entry->in_use_p[j / HOST_BITS_PER_LONG]
2177 |= 1L << (j % HOST_BITS_PER_LONG);
2179 for (pte = entry->page;
2180 pte < entry->page + entry->bytes;
2182 set_page_table_entry (pte, entry);
2184 if (G.page_tails[i] != NULL)
2185 G.page_tails[i]->next = entry;
2188 G.page_tails[i] = entry;
2190 /* We start off by just adding all the new information to the
2191 end of the varrays, later, we will move the new information
2192 to the front of the varrays, as the PCH page tables are at
2194 push_by_depth (entry, 0);
2197 /* Now, we update the various data structures that speed page table
2199 count_new_page_tables = G.by_depth_in_use - count_old_page_tables;
2201 move_ptes_to_front (count_old_page_tables, count_new_page_tables);
2203 /* Update the statistics. */
2204 G.allocated = G.allocated_last_gc = offs - (char *)addr;