name-lookup.c (lookup_arg_dependent): Use conditional timevars.
[official-gcc.git] / gcc / ggc-page.c
blob624f02971e559aedcd688dd7f5c6eba7e562733c
1 /* "Bag-of-pages" garbage collector for the GNU compiler.
2 Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009,
3 2010 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "tm.h"
25 #include "tree.h"
26 #include "rtl.h"
27 #include "tm_p.h"
28 #include "diagnostic-core.h"
29 #include "flags.h"
30 #include "ggc.h"
31 #include "ggc-internal.h"
32 #include "timevar.h"
33 #include "params.h"
34 #include "tree-flow.h"
35 #include "cfgloop.h"
36 #include "plugin.h"
38 /* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a
39 file open. Prefer either to valloc. */
40 #ifdef HAVE_MMAP_ANON
41 # undef HAVE_MMAP_DEV_ZERO
42 # define USING_MMAP
43 #endif
45 #ifdef HAVE_MMAP_DEV_ZERO
46 # define USING_MMAP
47 #endif
49 #ifndef USING_MMAP
50 #define USING_MALLOC_PAGE_GROUPS
51 #endif
53 /* Strategy:
55 This garbage-collecting allocator allocates objects on one of a set
56 of pages. Each page can allocate objects of a single size only;
57 available sizes are powers of two starting at four bytes. The size
58 of an allocation request is rounded up to the next power of two
59 (`order'), and satisfied from the appropriate page.
61 Each page is recorded in a page-entry, which also maintains an
62 in-use bitmap of object positions on the page. This allows the
63 allocation state of a particular object to be flipped without
64 touching the page itself.
66 Each page-entry also has a context depth, which is used to track
67 pushing and popping of allocation contexts. Only objects allocated
68 in the current (highest-numbered) context may be collected.
70 Page entries are arranged in an array of singly-linked lists. The
71 array is indexed by the allocation size, in bits, of the pages on
72 it; i.e. all pages on a list allocate objects of the same size.
73 Pages are ordered on the list such that all non-full pages precede
74 all full pages, with non-full pages arranged in order of decreasing
75 context depth.
77 Empty pages (of all orders) are kept on a single page cache list,
78 and are considered first when new pages are required; they are
79 deallocated at the start of the next collection if they haven't
80 been recycled by then. */
82 /* Define GGC_DEBUG_LEVEL to print debugging information.
83 0: No debugging output.
84 1: GC statistics only.
85 2: Page-entry allocations/deallocations as well.
86 3: Object allocations as well.
87 4: Object marks as well. */
88 #define GGC_DEBUG_LEVEL (0)
90 #ifndef HOST_BITS_PER_PTR
91 #define HOST_BITS_PER_PTR HOST_BITS_PER_LONG
92 #endif
95 /* A two-level tree is used to look up the page-entry for a given
96 pointer. Two chunks of the pointer's bits are extracted to index
97 the first and second levels of the tree, as follows:
99 HOST_PAGE_SIZE_BITS
100 32 | |
101 msb +----------------+----+------+------+ lsb
102 | | |
103 PAGE_L1_BITS |
105 PAGE_L2_BITS
107 The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry
108 pages are aligned on system page boundaries. The next most
109 significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first
110 index values in the lookup table, respectively.
112 For 32-bit architectures and the settings below, there are no
113 leftover bits. For architectures with wider pointers, the lookup
114 tree points to a list of pages, which must be scanned to find the
115 correct one. */
117 #define PAGE_L1_BITS (8)
118 #define PAGE_L2_BITS (32 - PAGE_L1_BITS - G.lg_pagesize)
119 #define PAGE_L1_SIZE ((size_t) 1 << PAGE_L1_BITS)
120 #define PAGE_L2_SIZE ((size_t) 1 << PAGE_L2_BITS)
122 #define LOOKUP_L1(p) \
123 (((size_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1))
125 #define LOOKUP_L2(p) \
126 (((size_t) (p) >> G.lg_pagesize) & ((1 << PAGE_L2_BITS) - 1))
128 /* The number of objects per allocation page, for objects on a page of
129 the indicated ORDER. */
130 #define OBJECTS_PER_PAGE(ORDER) objects_per_page_table[ORDER]
132 /* The number of objects in P. */
133 #define OBJECTS_IN_PAGE(P) ((P)->bytes / OBJECT_SIZE ((P)->order))
135 /* The size of an object on a page of the indicated ORDER. */
136 #define OBJECT_SIZE(ORDER) object_size_table[ORDER]
138 /* For speed, we avoid doing a general integer divide to locate the
139 offset in the allocation bitmap, by precalculating numbers M, S
140 such that (O * M) >> S == O / Z (modulo 2^32), for any offset O
141 within the page which is evenly divisible by the object size Z. */
142 #define DIV_MULT(ORDER) inverse_table[ORDER].mult
143 #define DIV_SHIFT(ORDER) inverse_table[ORDER].shift
144 #define OFFSET_TO_BIT(OFFSET, ORDER) \
145 (((OFFSET) * DIV_MULT (ORDER)) >> DIV_SHIFT (ORDER))
147 /* We use this structure to determine the alignment required for
148 allocations. For power-of-two sized allocations, that's not a
149 problem, but it does matter for odd-sized allocations.
150 We do not care about alignment for floating-point types. */
152 struct max_alignment {
153 char c;
154 union {
155 HOST_WIDEST_INT i;
156 void *p;
157 } u;
160 /* The biggest alignment required. */
162 #define MAX_ALIGNMENT (offsetof (struct max_alignment, u))
165 /* The number of extra orders, not corresponding to power-of-two sized
166 objects. */
168 #define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table)
170 #define RTL_SIZE(NSLOTS) \
171 (RTX_HDR_SIZE + (NSLOTS) * sizeof (rtunion))
173 #define TREE_EXP_SIZE(OPS) \
174 (sizeof (struct tree_exp) + ((OPS) - 1) * sizeof (tree))
176 /* The Ith entry is the maximum size of an object to be stored in the
177 Ith extra order. Adding a new entry to this array is the *only*
178 thing you need to do to add a new special allocation size. */
180 static const size_t extra_order_size_table[] = {
181 /* Extra orders for small non-power-of-two multiples of MAX_ALIGNMENT.
182 There are a lot of structures with these sizes and explicitly
183 listing them risks orders being dropped because they changed size. */
184 MAX_ALIGNMENT * 3,
185 MAX_ALIGNMENT * 5,
186 MAX_ALIGNMENT * 6,
187 MAX_ALIGNMENT * 7,
188 MAX_ALIGNMENT * 9,
189 MAX_ALIGNMENT * 10,
190 MAX_ALIGNMENT * 11,
191 MAX_ALIGNMENT * 12,
192 MAX_ALIGNMENT * 13,
193 MAX_ALIGNMENT * 14,
194 MAX_ALIGNMENT * 15,
195 sizeof (struct tree_decl_non_common),
196 sizeof (struct tree_field_decl),
197 sizeof (struct tree_parm_decl),
198 sizeof (struct tree_var_decl),
199 sizeof (struct tree_type_non_common),
200 sizeof (struct function),
201 sizeof (struct basic_block_def),
202 sizeof (struct cgraph_node),
203 sizeof (struct loop),
206 /* The total number of orders. */
208 #define NUM_ORDERS (HOST_BITS_PER_PTR + NUM_EXTRA_ORDERS)
210 /* Compute the smallest nonnegative number which when added to X gives
211 a multiple of F. */
213 #define ROUND_UP_VALUE(x, f) ((f) - 1 - ((f) - 1 + (x)) % (f))
215 /* Compute the smallest multiple of F that is >= X. */
217 #define ROUND_UP(x, f) (CEIL (x, f) * (f))
219 /* The Ith entry is the number of objects on a page or order I. */
221 static unsigned objects_per_page_table[NUM_ORDERS];
223 /* The Ith entry is the size of an object on a page of order I. */
225 static size_t object_size_table[NUM_ORDERS];
227 /* The Ith entry is a pair of numbers (mult, shift) such that
228 ((k * mult) >> shift) mod 2^32 == (k / OBJECT_SIZE(I)) mod 2^32,
229 for all k evenly divisible by OBJECT_SIZE(I). */
231 static struct
233 size_t mult;
234 unsigned int shift;
236 inverse_table[NUM_ORDERS];
238 /* A page_entry records the status of an allocation page. This
239 structure is dynamically sized to fit the bitmap in_use_p. */
240 typedef struct page_entry
242 /* The next page-entry with objects of the same size, or NULL if
243 this is the last page-entry. */
244 struct page_entry *next;
246 /* The previous page-entry with objects of the same size, or NULL if
247 this is the first page-entry. The PREV pointer exists solely to
248 keep the cost of ggc_free manageable. */
249 struct page_entry *prev;
251 /* The number of bytes allocated. (This will always be a multiple
252 of the host system page size.) */
253 size_t bytes;
255 /* The address at which the memory is allocated. */
256 char *page;
258 #ifdef USING_MALLOC_PAGE_GROUPS
259 /* Back pointer to the page group this page came from. */
260 struct page_group *group;
261 #endif
263 /* This is the index in the by_depth varray where this page table
264 can be found. */
265 unsigned long index_by_depth;
267 /* Context depth of this page. */
268 unsigned short context_depth;
270 /* The number of free objects remaining on this page. */
271 unsigned short num_free_objects;
273 /* A likely candidate for the bit position of a free object for the
274 next allocation from this page. */
275 unsigned short next_bit_hint;
277 /* The lg of size of objects allocated from this page. */
278 unsigned char order;
280 /* A bit vector indicating whether or not objects are in use. The
281 Nth bit is one if the Nth object on this page is allocated. This
282 array is dynamically sized. */
283 unsigned long in_use_p[1];
284 } page_entry;
286 #ifdef USING_MALLOC_PAGE_GROUPS
287 /* A page_group describes a large allocation from malloc, from which
288 we parcel out aligned pages. */
289 typedef struct page_group
291 /* A linked list of all extant page groups. */
292 struct page_group *next;
294 /* The address we received from malloc. */
295 char *allocation;
297 /* The size of the block. */
298 size_t alloc_size;
300 /* A bitmask of pages in use. */
301 unsigned int in_use;
302 } page_group;
303 #endif
305 #if HOST_BITS_PER_PTR <= 32
307 /* On 32-bit hosts, we use a two level page table, as pictured above. */
308 typedef page_entry **page_table[PAGE_L1_SIZE];
310 #else
312 /* On 64-bit hosts, we use the same two level page tables plus a linked
313 list that disambiguates the top 32-bits. There will almost always be
314 exactly one entry in the list. */
315 typedef struct page_table_chain
317 struct page_table_chain *next;
318 size_t high_bits;
319 page_entry **table[PAGE_L1_SIZE];
320 } *page_table;
322 #endif
324 #ifdef ENABLE_GC_ALWAYS_COLLECT
325 /* List of free objects to be verified as actually free on the
326 next collection. */
327 struct free_object
329 void *object;
330 struct free_object *next;
332 #endif
334 /* The rest of the global variables. */
335 static struct globals
337 /* The Nth element in this array is a page with objects of size 2^N.
338 If there are any pages with free objects, they will be at the
339 head of the list. NULL if there are no page-entries for this
340 object size. */
341 page_entry *pages[NUM_ORDERS];
343 /* The Nth element in this array is the last page with objects of
344 size 2^N. NULL if there are no page-entries for this object
345 size. */
346 page_entry *page_tails[NUM_ORDERS];
348 /* Lookup table for associating allocation pages with object addresses. */
349 page_table lookup;
351 /* The system's page size. */
352 size_t pagesize;
353 size_t lg_pagesize;
355 /* Bytes currently allocated. */
356 size_t allocated;
358 /* Bytes currently allocated at the end of the last collection. */
359 size_t allocated_last_gc;
361 /* Total amount of memory mapped. */
362 size_t bytes_mapped;
364 /* Bit N set if any allocations have been done at context depth N. */
365 unsigned long context_depth_allocations;
367 /* Bit N set if any collections have been done at context depth N. */
368 unsigned long context_depth_collections;
370 /* The current depth in the context stack. */
371 unsigned short context_depth;
373 /* A file descriptor open to /dev/zero for reading. */
374 #if defined (HAVE_MMAP_DEV_ZERO)
375 int dev_zero_fd;
376 #endif
378 /* A cache of free system pages. */
379 page_entry *free_pages;
381 #ifdef USING_MALLOC_PAGE_GROUPS
382 page_group *page_groups;
383 #endif
385 /* The file descriptor for debugging output. */
386 FILE *debug_file;
388 /* Current number of elements in use in depth below. */
389 unsigned int depth_in_use;
391 /* Maximum number of elements that can be used before resizing. */
392 unsigned int depth_max;
394 /* Each element of this array is an index in by_depth where the given
395 depth starts. This structure is indexed by that given depth we
396 are interested in. */
397 unsigned int *depth;
399 /* Current number of elements in use in by_depth below. */
400 unsigned int by_depth_in_use;
402 /* Maximum number of elements that can be used before resizing. */
403 unsigned int by_depth_max;
405 /* Each element of this array is a pointer to a page_entry, all
406 page_entries can be found in here by increasing depth.
407 index_by_depth in the page_entry is the index into this data
408 structure where that page_entry can be found. This is used to
409 speed up finding all page_entries at a particular depth. */
410 page_entry **by_depth;
412 /* Each element is a pointer to the saved in_use_p bits, if any,
413 zero otherwise. We allocate them all together, to enable a
414 better runtime data access pattern. */
415 unsigned long **save_in_use;
417 #ifdef ENABLE_GC_ALWAYS_COLLECT
418 /* List of free objects to be verified as actually free on the
419 next collection. */
420 struct free_object *free_object_list;
421 #endif
423 #ifdef GATHER_STATISTICS
424 struct
426 /* Total GC-allocated memory. */
427 unsigned long long total_allocated;
428 /* Total overhead for GC-allocated memory. */
429 unsigned long long total_overhead;
431 /* Total allocations and overhead for sizes less than 32, 64 and 128.
432 These sizes are interesting because they are typical cache line
433 sizes. */
435 unsigned long long total_allocated_under32;
436 unsigned long long total_overhead_under32;
438 unsigned long long total_allocated_under64;
439 unsigned long long total_overhead_under64;
441 unsigned long long total_allocated_under128;
442 unsigned long long total_overhead_under128;
444 /* The allocations for each of the allocation orders. */
445 unsigned long long total_allocated_per_order[NUM_ORDERS];
447 /* The overhead for each of the allocation orders. */
448 unsigned long long total_overhead_per_order[NUM_ORDERS];
449 } stats;
450 #endif
451 } G;
453 /* The size in bytes required to maintain a bitmap for the objects
454 on a page-entry. */
455 #define BITMAP_SIZE(Num_objects) \
456 (CEIL ((Num_objects), HOST_BITS_PER_LONG) * sizeof(long))
458 /* Allocate pages in chunks of this size, to throttle calls to memory
459 allocation routines. The first page is used, the rest go onto the
460 free list. This cannot be larger than HOST_BITS_PER_INT for the
461 in_use bitmask for page_group. Hosts that need a different value
462 can override this by defining GGC_QUIRE_SIZE explicitly. */
463 #ifndef GGC_QUIRE_SIZE
464 # ifdef USING_MMAP
465 # define GGC_QUIRE_SIZE 256
466 # else
467 # define GGC_QUIRE_SIZE 16
468 # endif
469 #endif
471 /* Initial guess as to how many page table entries we might need. */
472 #define INITIAL_PTE_COUNT 128
474 static int ggc_allocated_p (const void *);
475 static page_entry *lookup_page_table_entry (const void *);
476 static void set_page_table_entry (void *, page_entry *);
477 #ifdef USING_MMAP
478 static char *alloc_anon (char *, size_t);
479 #endif
480 #ifdef USING_MALLOC_PAGE_GROUPS
481 static size_t page_group_index (char *, char *);
482 static void set_page_group_in_use (page_group *, char *);
483 static void clear_page_group_in_use (page_group *, char *);
484 #endif
485 static struct page_entry * alloc_page (unsigned);
486 static void free_page (struct page_entry *);
487 static void release_pages (void);
488 static void clear_marks (void);
489 static void sweep_pages (void);
490 static void ggc_recalculate_in_use_p (page_entry *);
491 static void compute_inverse (unsigned);
492 static inline void adjust_depth (void);
493 static void move_ptes_to_front (int, int);
495 void debug_print_page_list (int);
496 static void push_depth (unsigned int);
497 static void push_by_depth (page_entry *, unsigned long *);
499 /* Push an entry onto G.depth. */
501 inline static void
502 push_depth (unsigned int i)
504 if (G.depth_in_use >= G.depth_max)
506 G.depth_max *= 2;
507 G.depth = XRESIZEVEC (unsigned int, G.depth, G.depth_max);
509 G.depth[G.depth_in_use++] = i;
512 /* Push an entry onto G.by_depth and G.save_in_use. */
514 inline static void
515 push_by_depth (page_entry *p, unsigned long *s)
517 if (G.by_depth_in_use >= G.by_depth_max)
519 G.by_depth_max *= 2;
520 G.by_depth = XRESIZEVEC (page_entry *, G.by_depth, G.by_depth_max);
521 G.save_in_use = XRESIZEVEC (unsigned long *, G.save_in_use,
522 G.by_depth_max);
524 G.by_depth[G.by_depth_in_use] = p;
525 G.save_in_use[G.by_depth_in_use++] = s;
528 #if (GCC_VERSION < 3001)
529 #define prefetch(X) ((void) X)
530 #else
531 #define prefetch(X) __builtin_prefetch (X)
532 #endif
534 #define save_in_use_p_i(__i) \
535 (G.save_in_use[__i])
536 #define save_in_use_p(__p) \
537 (save_in_use_p_i (__p->index_by_depth))
539 /* Returns nonzero if P was allocated in GC'able memory. */
541 static inline int
542 ggc_allocated_p (const void *p)
544 page_entry ***base;
545 size_t L1, L2;
547 #if HOST_BITS_PER_PTR <= 32
548 base = &G.lookup[0];
549 #else
550 page_table table = G.lookup;
551 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
552 while (1)
554 if (table == NULL)
555 return 0;
556 if (table->high_bits == high_bits)
557 break;
558 table = table->next;
560 base = &table->table[0];
561 #endif
563 /* Extract the level 1 and 2 indices. */
564 L1 = LOOKUP_L1 (p);
565 L2 = LOOKUP_L2 (p);
567 return base[L1] && base[L1][L2];
570 /* Traverse the page table and find the entry for a page.
571 Die (probably) if the object wasn't allocated via GC. */
573 static inline page_entry *
574 lookup_page_table_entry (const void *p)
576 page_entry ***base;
577 size_t L1, L2;
579 #if HOST_BITS_PER_PTR <= 32
580 base = &G.lookup[0];
581 #else
582 page_table table = G.lookup;
583 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
584 while (table->high_bits != high_bits)
585 table = table->next;
586 base = &table->table[0];
587 #endif
589 /* Extract the level 1 and 2 indices. */
590 L1 = LOOKUP_L1 (p);
591 L2 = LOOKUP_L2 (p);
593 return base[L1][L2];
596 /* Set the page table entry for a page. */
598 static void
599 set_page_table_entry (void *p, page_entry *entry)
601 page_entry ***base;
602 size_t L1, L2;
604 #if HOST_BITS_PER_PTR <= 32
605 base = &G.lookup[0];
606 #else
607 page_table table;
608 size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff;
609 for (table = G.lookup; table; table = table->next)
610 if (table->high_bits == high_bits)
611 goto found;
613 /* Not found -- allocate a new table. */
614 table = XCNEW (struct page_table_chain);
615 table->next = G.lookup;
616 table->high_bits = high_bits;
617 G.lookup = table;
618 found:
619 base = &table->table[0];
620 #endif
622 /* Extract the level 1 and 2 indices. */
623 L1 = LOOKUP_L1 (p);
624 L2 = LOOKUP_L2 (p);
626 if (base[L1] == NULL)
627 base[L1] = XCNEWVEC (page_entry *, PAGE_L2_SIZE);
629 base[L1][L2] = entry;
632 /* Prints the page-entry for object size ORDER, for debugging. */
634 DEBUG_FUNCTION void
635 debug_print_page_list (int order)
637 page_entry *p;
638 printf ("Head=%p, Tail=%p:\n", (void *) G.pages[order],
639 (void *) G.page_tails[order]);
640 p = G.pages[order];
641 while (p != NULL)
643 printf ("%p(%1d|%3d) -> ", (void *) p, p->context_depth,
644 p->num_free_objects);
645 p = p->next;
647 printf ("NULL\n");
648 fflush (stdout);
651 #ifdef USING_MMAP
652 /* Allocate SIZE bytes of anonymous memory, preferably near PREF,
653 (if non-null). The ifdef structure here is intended to cause a
654 compile error unless exactly one of the HAVE_* is defined. */
656 static inline char *
657 alloc_anon (char *pref ATTRIBUTE_UNUSED, size_t size)
659 #ifdef HAVE_MMAP_ANON
660 char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
661 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
662 #endif
663 #ifdef HAVE_MMAP_DEV_ZERO
664 char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE,
665 MAP_PRIVATE, G.dev_zero_fd, 0);
666 #endif
668 if (page == (char *) MAP_FAILED)
670 perror ("virtual memory exhausted");
671 exit (FATAL_EXIT_CODE);
674 /* Remember that we allocated this memory. */
675 G.bytes_mapped += size;
677 /* Pretend we don't have access to the allocated pages. We'll enable
678 access to smaller pieces of the area in ggc_internal_alloc. Discard the
679 handle to avoid handle leak. */
680 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (page, size));
682 return page;
684 #endif
685 #ifdef USING_MALLOC_PAGE_GROUPS
686 /* Compute the index for this page into the page group. */
688 static inline size_t
689 page_group_index (char *allocation, char *page)
691 return (size_t) (page - allocation) >> G.lg_pagesize;
694 /* Set and clear the in_use bit for this page in the page group. */
696 static inline void
697 set_page_group_in_use (page_group *group, char *page)
699 group->in_use |= 1 << page_group_index (group->allocation, page);
702 static inline void
703 clear_page_group_in_use (page_group *group, char *page)
705 group->in_use &= ~(1 << page_group_index (group->allocation, page));
707 #endif
709 /* Allocate a new page for allocating objects of size 2^ORDER,
710 and return an entry for it. The entry is not added to the
711 appropriate page_table list. */
713 static inline struct page_entry *
714 alloc_page (unsigned order)
716 struct page_entry *entry, *p, **pp;
717 char *page;
718 size_t num_objects;
719 size_t bitmap_size;
720 size_t page_entry_size;
721 size_t entry_size;
722 #ifdef USING_MALLOC_PAGE_GROUPS
723 page_group *group;
724 #endif
726 num_objects = OBJECTS_PER_PAGE (order);
727 bitmap_size = BITMAP_SIZE (num_objects + 1);
728 page_entry_size = sizeof (page_entry) - sizeof (long) + bitmap_size;
729 entry_size = num_objects * OBJECT_SIZE (order);
730 if (entry_size < G.pagesize)
731 entry_size = G.pagesize;
733 entry = NULL;
734 page = NULL;
736 /* Check the list of free pages for one we can use. */
737 for (pp = &G.free_pages, p = *pp; p; pp = &p->next, p = *pp)
738 if (p->bytes == entry_size)
739 break;
741 if (p != NULL)
743 /* Recycle the allocated memory from this page ... */
744 *pp = p->next;
745 page = p->page;
747 #ifdef USING_MALLOC_PAGE_GROUPS
748 group = p->group;
749 #endif
751 /* ... and, if possible, the page entry itself. */
752 if (p->order == order)
754 entry = p;
755 memset (entry, 0, page_entry_size);
757 else
758 free (p);
760 #ifdef USING_MMAP
761 else if (entry_size == G.pagesize)
763 /* We want just one page. Allocate a bunch of them and put the
764 extras on the freelist. (Can only do this optimization with
765 mmap for backing store.) */
766 struct page_entry *e, *f = G.free_pages;
767 int i;
769 page = alloc_anon (NULL, G.pagesize * GGC_QUIRE_SIZE);
771 /* This loop counts down so that the chain will be in ascending
772 memory order. */
773 for (i = GGC_QUIRE_SIZE - 1; i >= 1; i--)
775 e = XCNEWVAR (struct page_entry, page_entry_size);
776 e->order = order;
777 e->bytes = G.pagesize;
778 e->page = page + (i << G.lg_pagesize);
779 e->next = f;
780 f = e;
783 G.free_pages = f;
785 else
786 page = alloc_anon (NULL, entry_size);
787 #endif
788 #ifdef USING_MALLOC_PAGE_GROUPS
789 else
791 /* Allocate a large block of memory and serve out the aligned
792 pages therein. This results in much less memory wastage
793 than the traditional implementation of valloc. */
795 char *allocation, *a, *enda;
796 size_t alloc_size, head_slop, tail_slop;
797 int multiple_pages = (entry_size == G.pagesize);
799 if (multiple_pages)
800 alloc_size = GGC_QUIRE_SIZE * G.pagesize;
801 else
802 alloc_size = entry_size + G.pagesize - 1;
803 allocation = XNEWVEC (char, alloc_size);
805 page = (char *) (((size_t) allocation + G.pagesize - 1) & -G.pagesize);
806 head_slop = page - allocation;
807 if (multiple_pages)
808 tail_slop = ((size_t) allocation + alloc_size) & (G.pagesize - 1);
809 else
810 tail_slop = alloc_size - entry_size - head_slop;
811 enda = allocation + alloc_size - tail_slop;
813 /* We allocated N pages, which are likely not aligned, leaving
814 us with N-1 usable pages. We plan to place the page_group
815 structure somewhere in the slop. */
816 if (head_slop >= sizeof (page_group))
817 group = (page_group *)page - 1;
818 else
820 /* We magically got an aligned allocation. Too bad, we have
821 to waste a page anyway. */
822 if (tail_slop == 0)
824 enda -= G.pagesize;
825 tail_slop += G.pagesize;
827 gcc_assert (tail_slop >= sizeof (page_group));
828 group = (page_group *)enda;
829 tail_slop -= sizeof (page_group);
832 /* Remember that we allocated this memory. */
833 group->next = G.page_groups;
834 group->allocation = allocation;
835 group->alloc_size = alloc_size;
836 group->in_use = 0;
837 G.page_groups = group;
838 G.bytes_mapped += alloc_size;
840 /* If we allocated multiple pages, put the rest on the free list. */
841 if (multiple_pages)
843 struct page_entry *e, *f = G.free_pages;
844 for (a = enda - G.pagesize; a != page; a -= G.pagesize)
846 e = XCNEWVAR (struct page_entry, page_entry_size);
847 e->order = order;
848 e->bytes = G.pagesize;
849 e->page = a;
850 e->group = group;
851 e->next = f;
852 f = e;
854 G.free_pages = f;
857 #endif
859 if (entry == NULL)
860 entry = XCNEWVAR (struct page_entry, page_entry_size);
862 entry->bytes = entry_size;
863 entry->page = page;
864 entry->context_depth = G.context_depth;
865 entry->order = order;
866 entry->num_free_objects = num_objects;
867 entry->next_bit_hint = 1;
869 G.context_depth_allocations |= (unsigned long)1 << G.context_depth;
871 #ifdef USING_MALLOC_PAGE_GROUPS
872 entry->group = group;
873 set_page_group_in_use (group, page);
874 #endif
876 /* Set the one-past-the-end in-use bit. This acts as a sentry as we
877 increment the hint. */
878 entry->in_use_p[num_objects / HOST_BITS_PER_LONG]
879 = (unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG);
881 set_page_table_entry (page, entry);
883 if (GGC_DEBUG_LEVEL >= 2)
884 fprintf (G.debug_file,
885 "Allocating page at %p, object size=%lu, data %p-%p\n",
886 (void *) entry, (unsigned long) OBJECT_SIZE (order), page,
887 page + entry_size - 1);
889 return entry;
892 /* Adjust the size of G.depth so that no index greater than the one
893 used by the top of the G.by_depth is used. */
895 static inline void
896 adjust_depth (void)
898 page_entry *top;
900 if (G.by_depth_in_use)
902 top = G.by_depth[G.by_depth_in_use-1];
904 /* Peel back indices in depth that index into by_depth, so that
905 as new elements are added to by_depth, we note the indices
906 of those elements, if they are for new context depths. */
907 while (G.depth_in_use > (size_t)top->context_depth+1)
908 --G.depth_in_use;
912 /* For a page that is no longer needed, put it on the free page list. */
914 static void
915 free_page (page_entry *entry)
917 if (GGC_DEBUG_LEVEL >= 2)
918 fprintf (G.debug_file,
919 "Deallocating page at %p, data %p-%p\n", (void *) entry,
920 entry->page, entry->page + entry->bytes - 1);
922 /* Mark the page as inaccessible. Discard the handle to avoid handle
923 leak. */
924 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (entry->page, entry->bytes));
926 set_page_table_entry (entry->page, NULL);
928 #ifdef USING_MALLOC_PAGE_GROUPS
929 clear_page_group_in_use (entry->group, entry->page);
930 #endif
932 if (G.by_depth_in_use > 1)
934 page_entry *top = G.by_depth[G.by_depth_in_use-1];
935 int i = entry->index_by_depth;
937 /* We cannot free a page from a context deeper than the current
938 one. */
939 gcc_assert (entry->context_depth == top->context_depth);
941 /* Put top element into freed slot. */
942 G.by_depth[i] = top;
943 G.save_in_use[i] = G.save_in_use[G.by_depth_in_use-1];
944 top->index_by_depth = i;
946 --G.by_depth_in_use;
948 adjust_depth ();
950 entry->next = G.free_pages;
951 G.free_pages = entry;
954 /* Release the free page cache to the system. */
956 static void
957 release_pages (void)
959 #ifdef USING_MMAP
960 page_entry *p, *next;
961 char *start;
962 size_t len;
964 /* Gather up adjacent pages so they are unmapped together. */
965 p = G.free_pages;
967 while (p)
969 start = p->page;
970 next = p->next;
971 len = p->bytes;
972 free (p);
973 p = next;
975 while (p && p->page == start + len)
977 next = p->next;
978 len += p->bytes;
979 free (p);
980 p = next;
983 munmap (start, len);
984 G.bytes_mapped -= len;
987 G.free_pages = NULL;
988 #endif
989 #ifdef USING_MALLOC_PAGE_GROUPS
990 page_entry **pp, *p;
991 page_group **gp, *g;
993 /* Remove all pages from free page groups from the list. */
994 pp = &G.free_pages;
995 while ((p = *pp) != NULL)
996 if (p->group->in_use == 0)
998 *pp = p->next;
999 free (p);
1001 else
1002 pp = &p->next;
1004 /* Remove all free page groups, and release the storage. */
1005 gp = &G.page_groups;
1006 while ((g = *gp) != NULL)
1007 if (g->in_use == 0)
1009 *gp = g->next;
1010 G.bytes_mapped -= g->alloc_size;
1011 free (g->allocation);
1013 else
1014 gp = &g->next;
1015 #endif
1018 /* This table provides a fast way to determine ceil(log_2(size)) for
1019 allocation requests. The minimum allocation size is eight bytes. */
1020 #define NUM_SIZE_LOOKUP 512
1021 static unsigned char size_lookup[NUM_SIZE_LOOKUP] =
1023 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4,
1024 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
1025 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1026 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
1027 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1028 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1029 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1030 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
1031 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1032 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1033 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1034 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1035 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1036 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1037 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1038 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
1039 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1040 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1041 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1042 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1043 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1044 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1045 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1046 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1047 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1048 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1049 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1050 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1051 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1052 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1053 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
1054 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9
1057 /* Typed allocation function. Does nothing special in this collector. */
1059 void *
1060 ggc_alloc_typed_stat (enum gt_types_enum type ATTRIBUTE_UNUSED, size_t size
1061 MEM_STAT_DECL)
1063 return ggc_internal_alloc_stat (size PASS_MEM_STAT);
1066 /* Allocate a chunk of memory of SIZE bytes. Its contents are undefined. */
1068 void *
1069 ggc_internal_alloc_stat (size_t size MEM_STAT_DECL)
1071 size_t order, word, bit, object_offset, object_size;
1072 struct page_entry *entry;
1073 void *result;
1075 if (size < NUM_SIZE_LOOKUP)
1077 order = size_lookup[size];
1078 object_size = OBJECT_SIZE (order);
1080 else
1082 order = 10;
1083 while (size > (object_size = OBJECT_SIZE (order)))
1084 order++;
1087 /* If there are non-full pages for this size allocation, they are at
1088 the head of the list. */
1089 entry = G.pages[order];
1091 /* If there is no page for this object size, or all pages in this
1092 context are full, allocate a new page. */
1093 if (entry == NULL || entry->num_free_objects == 0)
1095 struct page_entry *new_entry;
1096 new_entry = alloc_page (order);
1098 new_entry->index_by_depth = G.by_depth_in_use;
1099 push_by_depth (new_entry, 0);
1101 /* We can skip context depths, if we do, make sure we go all the
1102 way to the new depth. */
1103 while (new_entry->context_depth >= G.depth_in_use)
1104 push_depth (G.by_depth_in_use-1);
1106 /* If this is the only entry, it's also the tail. If it is not
1107 the only entry, then we must update the PREV pointer of the
1108 ENTRY (G.pages[order]) to point to our new page entry. */
1109 if (entry == NULL)
1110 G.page_tails[order] = new_entry;
1111 else
1112 entry->prev = new_entry;
1114 /* Put new pages at the head of the page list. By definition the
1115 entry at the head of the list always has a NULL pointer. */
1116 new_entry->next = entry;
1117 new_entry->prev = NULL;
1118 entry = new_entry;
1119 G.pages[order] = new_entry;
1121 /* For a new page, we know the word and bit positions (in the
1122 in_use bitmap) of the first available object -- they're zero. */
1123 new_entry->next_bit_hint = 1;
1124 word = 0;
1125 bit = 0;
1126 object_offset = 0;
1128 else
1130 /* First try to use the hint left from the previous allocation
1131 to locate a clear bit in the in-use bitmap. We've made sure
1132 that the one-past-the-end bit is always set, so if the hint
1133 has run over, this test will fail. */
1134 unsigned hint = entry->next_bit_hint;
1135 word = hint / HOST_BITS_PER_LONG;
1136 bit = hint % HOST_BITS_PER_LONG;
1138 /* If the hint didn't work, scan the bitmap from the beginning. */
1139 if ((entry->in_use_p[word] >> bit) & 1)
1141 word = bit = 0;
1142 while (~entry->in_use_p[word] == 0)
1143 ++word;
1145 #if GCC_VERSION >= 3004
1146 bit = __builtin_ctzl (~entry->in_use_p[word]);
1147 #else
1148 while ((entry->in_use_p[word] >> bit) & 1)
1149 ++bit;
1150 #endif
1152 hint = word * HOST_BITS_PER_LONG + bit;
1155 /* Next time, try the next bit. */
1156 entry->next_bit_hint = hint + 1;
1158 object_offset = hint * object_size;
1161 /* Set the in-use bit. */
1162 entry->in_use_p[word] |= ((unsigned long) 1 << bit);
1164 /* Keep a running total of the number of free objects. If this page
1165 fills up, we may have to move it to the end of the list if the
1166 next page isn't full. If the next page is full, all subsequent
1167 pages are full, so there's no need to move it. */
1168 if (--entry->num_free_objects == 0
1169 && entry->next != NULL
1170 && entry->next->num_free_objects > 0)
1172 /* We have a new head for the list. */
1173 G.pages[order] = entry->next;
1175 /* We are moving ENTRY to the end of the page table list.
1176 The new page at the head of the list will have NULL in
1177 its PREV field and ENTRY will have NULL in its NEXT field. */
1178 entry->next->prev = NULL;
1179 entry->next = NULL;
1181 /* Append ENTRY to the tail of the list. */
1182 entry->prev = G.page_tails[order];
1183 G.page_tails[order]->next = entry;
1184 G.page_tails[order] = entry;
1187 /* Calculate the object's address. */
1188 result = entry->page + object_offset;
1189 #ifdef GATHER_STATISTICS
1190 ggc_record_overhead (OBJECT_SIZE (order), OBJECT_SIZE (order) - size,
1191 result PASS_MEM_STAT);
1192 #endif
1194 #ifdef ENABLE_GC_CHECKING
1195 /* Keep poisoning-by-writing-0xaf the object, in an attempt to keep the
1196 exact same semantics in presence of memory bugs, regardless of
1197 ENABLE_VALGRIND_CHECKING. We override this request below. Drop the
1198 handle to avoid handle leak. */
1199 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, object_size));
1201 /* `Poison' the entire allocated object, including any padding at
1202 the end. */
1203 memset (result, 0xaf, object_size);
1205 /* Make the bytes after the end of the object unaccessible. Discard the
1206 handle to avoid handle leak. */
1207 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS ((char *) result + size,
1208 object_size - size));
1209 #endif
1211 /* Tell Valgrind that the memory is there, but its content isn't
1212 defined. The bytes at the end of the object are still marked
1213 unaccessible. */
1214 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (result, size));
1216 /* Keep track of how many bytes are being allocated. This
1217 information is used in deciding when to collect. */
1218 G.allocated += object_size;
1220 /* For timevar statistics. */
1221 timevar_ggc_mem_total += object_size;
1223 #ifdef GATHER_STATISTICS
1225 size_t overhead = object_size - size;
1227 G.stats.total_overhead += overhead;
1228 G.stats.total_allocated += object_size;
1229 G.stats.total_overhead_per_order[order] += overhead;
1230 G.stats.total_allocated_per_order[order] += object_size;
1232 if (size <= 32)
1234 G.stats.total_overhead_under32 += overhead;
1235 G.stats.total_allocated_under32 += object_size;
1237 if (size <= 64)
1239 G.stats.total_overhead_under64 += overhead;
1240 G.stats.total_allocated_under64 += object_size;
1242 if (size <= 128)
1244 G.stats.total_overhead_under128 += overhead;
1245 G.stats.total_allocated_under128 += object_size;
1248 #endif
1250 if (GGC_DEBUG_LEVEL >= 3)
1251 fprintf (G.debug_file,
1252 "Allocating object, requested size=%lu, actual=%lu at %p on %p\n",
1253 (unsigned long) size, (unsigned long) object_size, result,
1254 (void *) entry);
1256 return result;
1259 /* Mark function for strings. */
1261 void
1262 gt_ggc_m_S (const void *p)
1264 page_entry *entry;
1265 unsigned bit, word;
1266 unsigned long mask;
1267 unsigned long offset;
1269 if (!p || !ggc_allocated_p (p))
1270 return;
1272 /* Look up the page on which the object is alloced. . */
1273 entry = lookup_page_table_entry (p);
1274 gcc_assert (entry);
1276 /* Calculate the index of the object on the page; this is its bit
1277 position in the in_use_p bitmap. Note that because a char* might
1278 point to the middle of an object, we need special code here to
1279 make sure P points to the start of an object. */
1280 offset = ((const char *) p - entry->page) % object_size_table[entry->order];
1281 if (offset)
1283 /* Here we've seen a char* which does not point to the beginning
1284 of an allocated object. We assume it points to the middle of
1285 a STRING_CST. */
1286 gcc_assert (offset == offsetof (struct tree_string, str));
1287 p = ((const char *) p) - offset;
1288 gt_ggc_mx_lang_tree_node (CONST_CAST (void *, p));
1289 return;
1292 bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
1293 word = bit / HOST_BITS_PER_LONG;
1294 mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
1296 /* If the bit was previously set, skip it. */
1297 if (entry->in_use_p[word] & mask)
1298 return;
1300 /* Otherwise set it, and decrement the free object count. */
1301 entry->in_use_p[word] |= mask;
1302 entry->num_free_objects -= 1;
1304 if (GGC_DEBUG_LEVEL >= 4)
1305 fprintf (G.debug_file, "Marking %p\n", p);
1307 return;
1310 /* If P is not marked, marks it and return false. Otherwise return true.
1311 P must have been allocated by the GC allocator; it mustn't point to
1312 static objects, stack variables, or memory allocated with malloc. */
1315 ggc_set_mark (const void *p)
1317 page_entry *entry;
1318 unsigned bit, word;
1319 unsigned long mask;
1321 /* Look up the page on which the object is alloced. If the object
1322 wasn't allocated by the collector, we'll probably die. */
1323 entry = lookup_page_table_entry (p);
1324 gcc_assert (entry);
1326 /* Calculate the index of the object on the page; this is its bit
1327 position in the in_use_p bitmap. */
1328 bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
1329 word = bit / HOST_BITS_PER_LONG;
1330 mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
1332 /* If the bit was previously set, skip it. */
1333 if (entry->in_use_p[word] & mask)
1334 return 1;
1336 /* Otherwise set it, and decrement the free object count. */
1337 entry->in_use_p[word] |= mask;
1338 entry->num_free_objects -= 1;
1340 if (GGC_DEBUG_LEVEL >= 4)
1341 fprintf (G.debug_file, "Marking %p\n", p);
1343 return 0;
1346 /* Return 1 if P has been marked, zero otherwise.
1347 P must have been allocated by the GC allocator; it mustn't point to
1348 static objects, stack variables, or memory allocated with malloc. */
1351 ggc_marked_p (const void *p)
1353 page_entry *entry;
1354 unsigned bit, word;
1355 unsigned long mask;
1357 /* Look up the page on which the object is alloced. If the object
1358 wasn't allocated by the collector, we'll probably die. */
1359 entry = lookup_page_table_entry (p);
1360 gcc_assert (entry);
1362 /* Calculate the index of the object on the page; this is its bit
1363 position in the in_use_p bitmap. */
1364 bit = OFFSET_TO_BIT (((const char *) p) - entry->page, entry->order);
1365 word = bit / HOST_BITS_PER_LONG;
1366 mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG);
1368 return (entry->in_use_p[word] & mask) != 0;
1371 /* Return the size of the gc-able object P. */
1373 size_t
1374 ggc_get_size (const void *p)
1376 page_entry *pe = lookup_page_table_entry (p);
1377 return OBJECT_SIZE (pe->order);
1380 /* Release the memory for object P. */
1382 void
1383 ggc_free (void *p)
1385 page_entry *pe = lookup_page_table_entry (p);
1386 size_t order = pe->order;
1387 size_t size = OBJECT_SIZE (order);
1389 #ifdef GATHER_STATISTICS
1390 ggc_free_overhead (p);
1391 #endif
1393 if (GGC_DEBUG_LEVEL >= 3)
1394 fprintf (G.debug_file,
1395 "Freeing object, actual size=%lu, at %p on %p\n",
1396 (unsigned long) size, p, (void *) pe);
1398 #ifdef ENABLE_GC_CHECKING
1399 /* Poison the data, to indicate the data is garbage. */
1400 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (p, size));
1401 memset (p, 0xa5, size);
1402 #endif
1403 /* Let valgrind know the object is free. */
1404 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (p, size));
1406 #ifdef ENABLE_GC_ALWAYS_COLLECT
1407 /* In the completely-anal-checking mode, we do *not* immediately free
1408 the data, but instead verify that the data is *actually* not
1409 reachable the next time we collect. */
1411 struct free_object *fo = XNEW (struct free_object);
1412 fo->object = p;
1413 fo->next = G.free_object_list;
1414 G.free_object_list = fo;
1416 #else
1418 unsigned int bit_offset, word, bit;
1420 G.allocated -= size;
1422 /* Mark the object not-in-use. */
1423 bit_offset = OFFSET_TO_BIT (((const char *) p) - pe->page, order);
1424 word = bit_offset / HOST_BITS_PER_LONG;
1425 bit = bit_offset % HOST_BITS_PER_LONG;
1426 pe->in_use_p[word] &= ~(1UL << bit);
1428 if (pe->num_free_objects++ == 0)
1430 page_entry *p, *q;
1432 /* If the page is completely full, then it's supposed to
1433 be after all pages that aren't. Since we've freed one
1434 object from a page that was full, we need to move the
1435 page to the head of the list.
1437 PE is the node we want to move. Q is the previous node
1438 and P is the next node in the list. */
1439 q = pe->prev;
1440 if (q && q->num_free_objects == 0)
1442 p = pe->next;
1444 q->next = p;
1446 /* If PE was at the end of the list, then Q becomes the
1447 new end of the list. If PE was not the end of the
1448 list, then we need to update the PREV field for P. */
1449 if (!p)
1450 G.page_tails[order] = q;
1451 else
1452 p->prev = q;
1454 /* Move PE to the head of the list. */
1455 pe->next = G.pages[order];
1456 pe->prev = NULL;
1457 G.pages[order]->prev = pe;
1458 G.pages[order] = pe;
1461 /* Reset the hint bit to point to the only free object. */
1462 pe->next_bit_hint = bit_offset;
1465 #endif
1468 /* Subroutine of init_ggc which computes the pair of numbers used to
1469 perform division by OBJECT_SIZE (order) and fills in inverse_table[].
1471 This algorithm is taken from Granlund and Montgomery's paper
1472 "Division by Invariant Integers using Multiplication"
1473 (Proc. SIGPLAN PLDI, 1994), section 9 (Exact division by
1474 constants). */
1476 static void
1477 compute_inverse (unsigned order)
1479 size_t size, inv;
1480 unsigned int e;
1482 size = OBJECT_SIZE (order);
1483 e = 0;
1484 while (size % 2 == 0)
1486 e++;
1487 size >>= 1;
1490 inv = size;
1491 while (inv * size != 1)
1492 inv = inv * (2 - inv*size);
1494 DIV_MULT (order) = inv;
1495 DIV_SHIFT (order) = e;
1498 /* Initialize the ggc-mmap allocator. */
1499 void
1500 init_ggc (void)
1502 unsigned order;
1504 G.pagesize = getpagesize();
1505 G.lg_pagesize = exact_log2 (G.pagesize);
1507 #ifdef HAVE_MMAP_DEV_ZERO
1508 G.dev_zero_fd = open ("/dev/zero", O_RDONLY);
1509 if (G.dev_zero_fd == -1)
1510 internal_error ("open /dev/zero: %m");
1511 #endif
1513 #if 0
1514 G.debug_file = fopen ("ggc-mmap.debug", "w");
1515 #else
1516 G.debug_file = stdout;
1517 #endif
1519 #ifdef USING_MMAP
1520 /* StunOS has an amazing off-by-one error for the first mmap allocation
1521 after fiddling with RLIMIT_STACK. The result, as hard as it is to
1522 believe, is an unaligned page allocation, which would cause us to
1523 hork badly if we tried to use it. */
1525 char *p = alloc_anon (NULL, G.pagesize);
1526 struct page_entry *e;
1527 if ((size_t)p & (G.pagesize - 1))
1529 /* How losing. Discard this one and try another. If we still
1530 can't get something useful, give up. */
1532 p = alloc_anon (NULL, G.pagesize);
1533 gcc_assert (!((size_t)p & (G.pagesize - 1)));
1536 /* We have a good page, might as well hold onto it... */
1537 e = XCNEW (struct page_entry);
1538 e->bytes = G.pagesize;
1539 e->page = p;
1540 e->next = G.free_pages;
1541 G.free_pages = e;
1543 #endif
1545 /* Initialize the object size table. */
1546 for (order = 0; order < HOST_BITS_PER_PTR; ++order)
1547 object_size_table[order] = (size_t) 1 << order;
1548 for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order)
1550 size_t s = extra_order_size_table[order - HOST_BITS_PER_PTR];
1552 /* If S is not a multiple of the MAX_ALIGNMENT, then round it up
1553 so that we're sure of getting aligned memory. */
1554 s = ROUND_UP (s, MAX_ALIGNMENT);
1555 object_size_table[order] = s;
1558 /* Initialize the objects-per-page and inverse tables. */
1559 for (order = 0; order < NUM_ORDERS; ++order)
1561 objects_per_page_table[order] = G.pagesize / OBJECT_SIZE (order);
1562 if (objects_per_page_table[order] == 0)
1563 objects_per_page_table[order] = 1;
1564 compute_inverse (order);
1567 /* Reset the size_lookup array to put appropriately sized objects in
1568 the special orders. All objects bigger than the previous power
1569 of two, but no greater than the special size, should go in the
1570 new order. */
1571 for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order)
1573 int o;
1574 int i;
1576 i = OBJECT_SIZE (order);
1577 if (i >= NUM_SIZE_LOOKUP)
1578 continue;
1580 for (o = size_lookup[i]; o == size_lookup [i]; --i)
1581 size_lookup[i] = order;
1584 G.depth_in_use = 0;
1585 G.depth_max = 10;
1586 G.depth = XNEWVEC (unsigned int, G.depth_max);
1588 G.by_depth_in_use = 0;
1589 G.by_depth_max = INITIAL_PTE_COUNT;
1590 G.by_depth = XNEWVEC (page_entry *, G.by_depth_max);
1591 G.save_in_use = XNEWVEC (unsigned long *, G.by_depth_max);
1594 /* Merge the SAVE_IN_USE_P and IN_USE_P arrays in P so that IN_USE_P
1595 reflects reality. Recalculate NUM_FREE_OBJECTS as well. */
1597 static void
1598 ggc_recalculate_in_use_p (page_entry *p)
1600 unsigned int i;
1601 size_t num_objects;
1603 /* Because the past-the-end bit in in_use_p is always set, we
1604 pretend there is one additional object. */
1605 num_objects = OBJECTS_IN_PAGE (p) + 1;
1607 /* Reset the free object count. */
1608 p->num_free_objects = num_objects;
1610 /* Combine the IN_USE_P and SAVE_IN_USE_P arrays. */
1611 for (i = 0;
1612 i < CEIL (BITMAP_SIZE (num_objects),
1613 sizeof (*p->in_use_p));
1614 ++i)
1616 unsigned long j;
1618 /* Something is in use if it is marked, or if it was in use in a
1619 context further down the context stack. */
1620 p->in_use_p[i] |= save_in_use_p (p)[i];
1622 /* Decrement the free object count for every object allocated. */
1623 for (j = p->in_use_p[i]; j; j >>= 1)
1624 p->num_free_objects -= (j & 1);
1627 gcc_assert (p->num_free_objects < num_objects);
1630 /* Unmark all objects. */
1632 static void
1633 clear_marks (void)
1635 unsigned order;
1637 for (order = 2; order < NUM_ORDERS; order++)
1639 page_entry *p;
1641 for (p = G.pages[order]; p != NULL; p = p->next)
1643 size_t num_objects = OBJECTS_IN_PAGE (p);
1644 size_t bitmap_size = BITMAP_SIZE (num_objects + 1);
1646 /* The data should be page-aligned. */
1647 gcc_assert (!((size_t) p->page & (G.pagesize - 1)));
1649 /* Pages that aren't in the topmost context are not collected;
1650 nevertheless, we need their in-use bit vectors to store GC
1651 marks. So, back them up first. */
1652 if (p->context_depth < G.context_depth)
1654 if (! save_in_use_p (p))
1655 save_in_use_p (p) = XNEWVAR (unsigned long, bitmap_size);
1656 memcpy (save_in_use_p (p), p->in_use_p, bitmap_size);
1659 /* Reset reset the number of free objects and clear the
1660 in-use bits. These will be adjusted by mark_obj. */
1661 p->num_free_objects = num_objects;
1662 memset (p->in_use_p, 0, bitmap_size);
1664 /* Make sure the one-past-the-end bit is always set. */
1665 p->in_use_p[num_objects / HOST_BITS_PER_LONG]
1666 = ((unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG));
1671 /* Free all empty pages. Partially empty pages need no attention
1672 because the `mark' bit doubles as an `unused' bit. */
1674 static void
1675 sweep_pages (void)
1677 unsigned order;
1679 for (order = 2; order < NUM_ORDERS; order++)
1681 /* The last page-entry to consider, regardless of entries
1682 placed at the end of the list. */
1683 page_entry * const last = G.page_tails[order];
1685 size_t num_objects;
1686 size_t live_objects;
1687 page_entry *p, *previous;
1688 int done;
1690 p = G.pages[order];
1691 if (p == NULL)
1692 continue;
1694 previous = NULL;
1697 page_entry *next = p->next;
1699 /* Loop until all entries have been examined. */
1700 done = (p == last);
1702 num_objects = OBJECTS_IN_PAGE (p);
1704 /* Add all live objects on this page to the count of
1705 allocated memory. */
1706 live_objects = num_objects - p->num_free_objects;
1708 G.allocated += OBJECT_SIZE (order) * live_objects;
1710 /* Only objects on pages in the topmost context should get
1711 collected. */
1712 if (p->context_depth < G.context_depth)
1715 /* Remove the page if it's empty. */
1716 else if (live_objects == 0)
1718 /* If P was the first page in the list, then NEXT
1719 becomes the new first page in the list, otherwise
1720 splice P out of the forward pointers. */
1721 if (! previous)
1722 G.pages[order] = next;
1723 else
1724 previous->next = next;
1726 /* Splice P out of the back pointers too. */
1727 if (next)
1728 next->prev = previous;
1730 /* Are we removing the last element? */
1731 if (p == G.page_tails[order])
1732 G.page_tails[order] = previous;
1733 free_page (p);
1734 p = previous;
1737 /* If the page is full, move it to the end. */
1738 else if (p->num_free_objects == 0)
1740 /* Don't move it if it's already at the end. */
1741 if (p != G.page_tails[order])
1743 /* Move p to the end of the list. */
1744 p->next = NULL;
1745 p->prev = G.page_tails[order];
1746 G.page_tails[order]->next = p;
1748 /* Update the tail pointer... */
1749 G.page_tails[order] = p;
1751 /* ... and the head pointer, if necessary. */
1752 if (! previous)
1753 G.pages[order] = next;
1754 else
1755 previous->next = next;
1757 /* And update the backpointer in NEXT if necessary. */
1758 if (next)
1759 next->prev = previous;
1761 p = previous;
1765 /* If we've fallen through to here, it's a page in the
1766 topmost context that is neither full nor empty. Such a
1767 page must precede pages at lesser context depth in the
1768 list, so move it to the head. */
1769 else if (p != G.pages[order])
1771 previous->next = p->next;
1773 /* Update the backchain in the next node if it exists. */
1774 if (p->next)
1775 p->next->prev = previous;
1777 /* Move P to the head of the list. */
1778 p->next = G.pages[order];
1779 p->prev = NULL;
1780 G.pages[order]->prev = p;
1782 /* Update the head pointer. */
1783 G.pages[order] = p;
1785 /* Are we moving the last element? */
1786 if (G.page_tails[order] == p)
1787 G.page_tails[order] = previous;
1788 p = previous;
1791 previous = p;
1792 p = next;
1794 while (! done);
1796 /* Now, restore the in_use_p vectors for any pages from contexts
1797 other than the current one. */
1798 for (p = G.pages[order]; p; p = p->next)
1799 if (p->context_depth != G.context_depth)
1800 ggc_recalculate_in_use_p (p);
1804 #ifdef ENABLE_GC_CHECKING
1805 /* Clobber all free objects. */
1807 static void
1808 poison_pages (void)
1810 unsigned order;
1812 for (order = 2; order < NUM_ORDERS; order++)
1814 size_t size = OBJECT_SIZE (order);
1815 page_entry *p;
1817 for (p = G.pages[order]; p != NULL; p = p->next)
1819 size_t num_objects;
1820 size_t i;
1822 if (p->context_depth != G.context_depth)
1823 /* Since we don't do any collection for pages in pushed
1824 contexts, there's no need to do any poisoning. And
1825 besides, the IN_USE_P array isn't valid until we pop
1826 contexts. */
1827 continue;
1829 num_objects = OBJECTS_IN_PAGE (p);
1830 for (i = 0; i < num_objects; i++)
1832 size_t word, bit;
1833 word = i / HOST_BITS_PER_LONG;
1834 bit = i % HOST_BITS_PER_LONG;
1835 if (((p->in_use_p[word] >> bit) & 1) == 0)
1837 char *object = p->page + i * size;
1839 /* Keep poison-by-write when we expect to use Valgrind,
1840 so the exact same memory semantics is kept, in case
1841 there are memory errors. We override this request
1842 below. */
1843 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_UNDEFINED (object,
1844 size));
1845 memset (object, 0xa5, size);
1847 /* Drop the handle to avoid handle leak. */
1848 VALGRIND_DISCARD (VALGRIND_MAKE_MEM_NOACCESS (object, size));
1854 #else
1855 #define poison_pages()
1856 #endif
1858 #ifdef ENABLE_GC_ALWAYS_COLLECT
1859 /* Validate that the reportedly free objects actually are. */
1861 static void
1862 validate_free_objects (void)
1864 struct free_object *f, *next, *still_free = NULL;
1866 for (f = G.free_object_list; f ; f = next)
1868 page_entry *pe = lookup_page_table_entry (f->object);
1869 size_t bit, word;
1871 bit = OFFSET_TO_BIT ((char *)f->object - pe->page, pe->order);
1872 word = bit / HOST_BITS_PER_LONG;
1873 bit = bit % HOST_BITS_PER_LONG;
1874 next = f->next;
1876 /* Make certain it isn't visible from any root. Notice that we
1877 do this check before sweep_pages merges save_in_use_p. */
1878 gcc_assert (!(pe->in_use_p[word] & (1UL << bit)));
1880 /* If the object comes from an outer context, then retain the
1881 free_object entry, so that we can verify that the address
1882 isn't live on the stack in some outer context. */
1883 if (pe->context_depth != G.context_depth)
1885 f->next = still_free;
1886 still_free = f;
1888 else
1889 free (f);
1892 G.free_object_list = still_free;
1894 #else
1895 #define validate_free_objects()
1896 #endif
1898 /* Top level mark-and-sweep routine. */
1900 void
1901 ggc_collect (void)
1903 /* Avoid frequent unnecessary work by skipping collection if the
1904 total allocations haven't expanded much since the last
1905 collection. */
1906 float allocated_last_gc =
1907 MAX (G.allocated_last_gc, (size_t)PARAM_VALUE (GGC_MIN_HEAPSIZE) * 1024);
1909 float min_expand = allocated_last_gc * PARAM_VALUE (GGC_MIN_EXPAND) / 100;
1911 if (G.allocated < allocated_last_gc + min_expand && !ggc_force_collect)
1912 return;
1914 timevar_push (TV_GC);
1915 if (!quiet_flag)
1916 fprintf (stderr, " {GC %luk -> ", (unsigned long) G.allocated / 1024);
1917 if (GGC_DEBUG_LEVEL >= 2)
1918 fprintf (G.debug_file, "BEGIN COLLECTING\n");
1920 /* Zero the total allocated bytes. This will be recalculated in the
1921 sweep phase. */
1922 G.allocated = 0;
1924 /* Release the pages we freed the last time we collected, but didn't
1925 reuse in the interim. */
1926 release_pages ();
1928 /* Indicate that we've seen collections at this context depth. */
1929 G.context_depth_collections = ((unsigned long)1 << (G.context_depth + 1)) - 1;
1931 invoke_plugin_callbacks (PLUGIN_GGC_START, NULL);
1933 clear_marks ();
1934 ggc_mark_roots ();
1935 #ifdef GATHER_STATISTICS
1936 ggc_prune_overhead_list ();
1937 #endif
1938 poison_pages ();
1939 validate_free_objects ();
1940 sweep_pages ();
1942 G.allocated_last_gc = G.allocated;
1944 invoke_plugin_callbacks (PLUGIN_GGC_END, NULL);
1946 timevar_pop (TV_GC);
1948 if (!quiet_flag)
1949 fprintf (stderr, "%luk}", (unsigned long) G.allocated / 1024);
1950 if (GGC_DEBUG_LEVEL >= 2)
1951 fprintf (G.debug_file, "END COLLECTING\n");
1954 /* Print allocation statistics. */
1955 #define SCALE(x) ((unsigned long) ((x) < 1024*10 \
1956 ? (x) \
1957 : ((x) < 1024*1024*10 \
1958 ? (x) / 1024 \
1959 : (x) / (1024*1024))))
1960 #define STAT_LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M'))
1962 void
1963 ggc_print_statistics (void)
1965 struct ggc_statistics stats;
1966 unsigned int i;
1967 size_t total_overhead = 0;
1969 /* Clear the statistics. */
1970 memset (&stats, 0, sizeof (stats));
1972 /* Make sure collection will really occur. */
1973 G.allocated_last_gc = 0;
1975 /* Collect and print the statistics common across collectors. */
1976 ggc_print_common_statistics (stderr, &stats);
1978 /* Release free pages so that we will not count the bytes allocated
1979 there as part of the total allocated memory. */
1980 release_pages ();
1982 /* Collect some information about the various sizes of
1983 allocation. */
1984 fprintf (stderr,
1985 "Memory still allocated at the end of the compilation process\n");
1986 fprintf (stderr, "%-5s %10s %10s %10s\n",
1987 "Size", "Allocated", "Used", "Overhead");
1988 for (i = 0; i < NUM_ORDERS; ++i)
1990 page_entry *p;
1991 size_t allocated;
1992 size_t in_use;
1993 size_t overhead;
1995 /* Skip empty entries. */
1996 if (!G.pages[i])
1997 continue;
1999 overhead = allocated = in_use = 0;
2001 /* Figure out the total number of bytes allocated for objects of
2002 this size, and how many of them are actually in use. Also figure
2003 out how much memory the page table is using. */
2004 for (p = G.pages[i]; p; p = p->next)
2006 allocated += p->bytes;
2007 in_use +=
2008 (OBJECTS_IN_PAGE (p) - p->num_free_objects) * OBJECT_SIZE (i);
2010 overhead += (sizeof (page_entry) - sizeof (long)
2011 + BITMAP_SIZE (OBJECTS_IN_PAGE (p) + 1));
2013 fprintf (stderr, "%-5lu %10lu%c %10lu%c %10lu%c\n",
2014 (unsigned long) OBJECT_SIZE (i),
2015 SCALE (allocated), STAT_LABEL (allocated),
2016 SCALE (in_use), STAT_LABEL (in_use),
2017 SCALE (overhead), STAT_LABEL (overhead));
2018 total_overhead += overhead;
2020 fprintf (stderr, "%-5s %10lu%c %10lu%c %10lu%c\n", "Total",
2021 SCALE (G.bytes_mapped), STAT_LABEL (G.bytes_mapped),
2022 SCALE (G.allocated), STAT_LABEL(G.allocated),
2023 SCALE (total_overhead), STAT_LABEL (total_overhead));
2025 #ifdef GATHER_STATISTICS
2027 fprintf (stderr, "\nTotal allocations and overheads during the compilation process\n");
2029 fprintf (stderr, "Total Overhead: %10lld\n",
2030 G.stats.total_overhead);
2031 fprintf (stderr, "Total Allocated: %10lld\n",
2032 G.stats.total_allocated);
2034 fprintf (stderr, "Total Overhead under 32B: %10lld\n",
2035 G.stats.total_overhead_under32);
2036 fprintf (stderr, "Total Allocated under 32B: %10lld\n",
2037 G.stats.total_allocated_under32);
2038 fprintf (stderr, "Total Overhead under 64B: %10lld\n",
2039 G.stats.total_overhead_under64);
2040 fprintf (stderr, "Total Allocated under 64B: %10lld\n",
2041 G.stats.total_allocated_under64);
2042 fprintf (stderr, "Total Overhead under 128B: %10lld\n",
2043 G.stats.total_overhead_under128);
2044 fprintf (stderr, "Total Allocated under 128B: %10lld\n",
2045 G.stats.total_allocated_under128);
2047 for (i = 0; i < NUM_ORDERS; i++)
2048 if (G.stats.total_allocated_per_order[i])
2050 fprintf (stderr, "Total Overhead page size %7lu: %10lld\n",
2051 (unsigned long) OBJECT_SIZE (i),
2052 G.stats.total_overhead_per_order[i]);
2053 fprintf (stderr, "Total Allocated page size %7lu: %10lld\n",
2054 (unsigned long) OBJECT_SIZE (i),
2055 G.stats.total_allocated_per_order[i]);
2058 #endif
2061 struct ggc_pch_ondisk
2063 unsigned totals[NUM_ORDERS];
2066 struct ggc_pch_data
2068 struct ggc_pch_ondisk d;
2069 size_t base[NUM_ORDERS];
2070 size_t written[NUM_ORDERS];
2073 struct ggc_pch_data *
2074 init_ggc_pch (void)
2076 return XCNEW (struct ggc_pch_data);
2079 void
2080 ggc_pch_count_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
2081 size_t size, bool is_string ATTRIBUTE_UNUSED,
2082 enum gt_types_enum type ATTRIBUTE_UNUSED)
2084 unsigned order;
2086 if (size < NUM_SIZE_LOOKUP)
2087 order = size_lookup[size];
2088 else
2090 order = 10;
2091 while (size > OBJECT_SIZE (order))
2092 order++;
2095 d->d.totals[order]++;
2098 size_t
2099 ggc_pch_total_size (struct ggc_pch_data *d)
2101 size_t a = 0;
2102 unsigned i;
2104 for (i = 0; i < NUM_ORDERS; i++)
2105 a += ROUND_UP (d->d.totals[i] * OBJECT_SIZE (i), G.pagesize);
2106 return a;
2109 void
2110 ggc_pch_this_base (struct ggc_pch_data *d, void *base)
2112 size_t a = (size_t) base;
2113 unsigned i;
2115 for (i = 0; i < NUM_ORDERS; i++)
2117 d->base[i] = a;
2118 a += ROUND_UP (d->d.totals[i] * OBJECT_SIZE (i), G.pagesize);
2123 char *
2124 ggc_pch_alloc_object (struct ggc_pch_data *d, void *x ATTRIBUTE_UNUSED,
2125 size_t size, bool is_string ATTRIBUTE_UNUSED,
2126 enum gt_types_enum type ATTRIBUTE_UNUSED)
2128 unsigned order;
2129 char *result;
2131 if (size < NUM_SIZE_LOOKUP)
2132 order = size_lookup[size];
2133 else
2135 order = 10;
2136 while (size > OBJECT_SIZE (order))
2137 order++;
2140 result = (char *) d->base[order];
2141 d->base[order] += OBJECT_SIZE (order);
2142 return result;
2145 void
2146 ggc_pch_prepare_write (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
2147 FILE *f ATTRIBUTE_UNUSED)
2149 /* Nothing to do. */
2152 void
2153 ggc_pch_write_object (struct ggc_pch_data *d ATTRIBUTE_UNUSED,
2154 FILE *f, void *x, void *newx ATTRIBUTE_UNUSED,
2155 size_t size, bool is_string ATTRIBUTE_UNUSED)
2157 unsigned order;
2158 static const char emptyBytes[256] = { 0 };
2160 if (size < NUM_SIZE_LOOKUP)
2161 order = size_lookup[size];
2162 else
2164 order = 10;
2165 while (size > OBJECT_SIZE (order))
2166 order++;
2169 if (fwrite (x, size, 1, f) != 1)
2170 fatal_error ("can%'t write PCH file: %m");
2172 /* If SIZE is not the same as OBJECT_SIZE(order), then we need to pad the
2173 object out to OBJECT_SIZE(order). This happens for strings. */
2175 if (size != OBJECT_SIZE (order))
2177 unsigned padding = OBJECT_SIZE(order) - size;
2179 /* To speed small writes, we use a nulled-out array that's larger
2180 than most padding requests as the source for our null bytes. This
2181 permits us to do the padding with fwrite() rather than fseek(), and
2182 limits the chance the OS may try to flush any outstanding writes. */
2183 if (padding <= sizeof(emptyBytes))
2185 if (fwrite (emptyBytes, 1, padding, f) != padding)
2186 fatal_error ("can%'t write PCH file");
2188 else
2190 /* Larger than our buffer? Just default to fseek. */
2191 if (fseek (f, padding, SEEK_CUR) != 0)
2192 fatal_error ("can%'t write PCH file");
2196 d->written[order]++;
2197 if (d->written[order] == d->d.totals[order]
2198 && fseek (f, ROUND_UP_VALUE (d->d.totals[order] * OBJECT_SIZE (order),
2199 G.pagesize),
2200 SEEK_CUR) != 0)
2201 fatal_error ("can%'t write PCH file: %m");
2204 void
2205 ggc_pch_finish (struct ggc_pch_data *d, FILE *f)
2207 if (fwrite (&d->d, sizeof (d->d), 1, f) != 1)
2208 fatal_error ("can%'t write PCH file: %m");
2209 free (d);
2212 /* Move the PCH PTE entries just added to the end of by_depth, to the
2213 front. */
2215 static void
2216 move_ptes_to_front (int count_old_page_tables, int count_new_page_tables)
2218 unsigned i;
2220 /* First, we swap the new entries to the front of the varrays. */
2221 page_entry **new_by_depth;
2222 unsigned long **new_save_in_use;
2224 new_by_depth = XNEWVEC (page_entry *, G.by_depth_max);
2225 new_save_in_use = XNEWVEC (unsigned long *, G.by_depth_max);
2227 memcpy (&new_by_depth[0],
2228 &G.by_depth[count_old_page_tables],
2229 count_new_page_tables * sizeof (void *));
2230 memcpy (&new_by_depth[count_new_page_tables],
2231 &G.by_depth[0],
2232 count_old_page_tables * sizeof (void *));
2233 memcpy (&new_save_in_use[0],
2234 &G.save_in_use[count_old_page_tables],
2235 count_new_page_tables * sizeof (void *));
2236 memcpy (&new_save_in_use[count_new_page_tables],
2237 &G.save_in_use[0],
2238 count_old_page_tables * sizeof (void *));
2240 free (G.by_depth);
2241 free (G.save_in_use);
2243 G.by_depth = new_by_depth;
2244 G.save_in_use = new_save_in_use;
2246 /* Now update all the index_by_depth fields. */
2247 for (i = G.by_depth_in_use; i > 0; --i)
2249 page_entry *p = G.by_depth[i-1];
2250 p->index_by_depth = i-1;
2253 /* And last, we update the depth pointers in G.depth. The first
2254 entry is already 0, and context 0 entries always start at index
2255 0, so there is nothing to update in the first slot. We need a
2256 second slot, only if we have old ptes, and if we do, they start
2257 at index count_new_page_tables. */
2258 if (count_old_page_tables)
2259 push_depth (count_new_page_tables);
2262 void
2263 ggc_pch_read (FILE *f, void *addr)
2265 struct ggc_pch_ondisk d;
2266 unsigned i;
2267 char *offs = (char *) addr;
2268 unsigned long count_old_page_tables;
2269 unsigned long count_new_page_tables;
2271 count_old_page_tables = G.by_depth_in_use;
2273 /* We've just read in a PCH file. So, every object that used to be
2274 allocated is now free. */
2275 clear_marks ();
2276 #ifdef ENABLE_GC_CHECKING
2277 poison_pages ();
2278 #endif
2279 /* Since we free all the allocated objects, the free list becomes
2280 useless. Validate it now, which will also clear it. */
2281 validate_free_objects();
2283 /* No object read from a PCH file should ever be freed. So, set the
2284 context depth to 1, and set the depth of all the currently-allocated
2285 pages to be 1 too. PCH pages will have depth 0. */
2286 gcc_assert (!G.context_depth);
2287 G.context_depth = 1;
2288 for (i = 0; i < NUM_ORDERS; i++)
2290 page_entry *p;
2291 for (p = G.pages[i]; p != NULL; p = p->next)
2292 p->context_depth = G.context_depth;
2295 /* Allocate the appropriate page-table entries for the pages read from
2296 the PCH file. */
2297 if (fread (&d, sizeof (d), 1, f) != 1)
2298 fatal_error ("can%'t read PCH file: %m");
2300 for (i = 0; i < NUM_ORDERS; i++)
2302 struct page_entry *entry;
2303 char *pte;
2304 size_t bytes;
2305 size_t num_objs;
2306 size_t j;
2308 if (d.totals[i] == 0)
2309 continue;
2311 bytes = ROUND_UP (d.totals[i] * OBJECT_SIZE (i), G.pagesize);
2312 num_objs = bytes / OBJECT_SIZE (i);
2313 entry = XCNEWVAR (struct page_entry, (sizeof (struct page_entry)
2314 - sizeof (long)
2315 + BITMAP_SIZE (num_objs + 1)));
2316 entry->bytes = bytes;
2317 entry->page = offs;
2318 entry->context_depth = 0;
2319 offs += bytes;
2320 entry->num_free_objects = 0;
2321 entry->order = i;
2323 for (j = 0;
2324 j + HOST_BITS_PER_LONG <= num_objs + 1;
2325 j += HOST_BITS_PER_LONG)
2326 entry->in_use_p[j / HOST_BITS_PER_LONG] = -1;
2327 for (; j < num_objs + 1; j++)
2328 entry->in_use_p[j / HOST_BITS_PER_LONG]
2329 |= 1L << (j % HOST_BITS_PER_LONG);
2331 for (pte = entry->page;
2332 pte < entry->page + entry->bytes;
2333 pte += G.pagesize)
2334 set_page_table_entry (pte, entry);
2336 if (G.page_tails[i] != NULL)
2337 G.page_tails[i]->next = entry;
2338 else
2339 G.pages[i] = entry;
2340 G.page_tails[i] = entry;
2342 /* We start off by just adding all the new information to the
2343 end of the varrays, later, we will move the new information
2344 to the front of the varrays, as the PCH page tables are at
2345 context 0. */
2346 push_by_depth (entry, 0);
2349 /* Now, we update the various data structures that speed page table
2350 handling. */
2351 count_new_page_tables = G.by_depth_in_use - count_old_page_tables;
2353 move_ptes_to_front (count_old_page_tables, count_new_page_tables);
2355 /* Update the statistics. */
2356 G.allocated = G.allocated_last_gc = offs - (char *)addr;
2359 struct alloc_zone
2361 int dummy;
2364 struct alloc_zone rtl_zone;
2365 struct alloc_zone tree_zone;
2366 struct alloc_zone tree_id_zone;