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21341cfd | 1 | /* "Bag-of-pages" garbage collector for the GNU compiler. |
c4f2c499 | 2 | Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc. |
21341cfd | 3 | |
1322177d | 4 | This file is part of GCC. |
21341cfd | 5 | |
1322177d LB |
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 | |
9 | version. | |
21341cfd | 10 | |
1322177d LB |
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 | |
14 | for more details. | |
21341cfd | 15 | |
b9bfacf0 | 16 | You should have received a copy of the GNU General Public License |
1322177d LB |
17 | along with GCC; see the file COPYING. If not, write to the Free |
18 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA | |
19 | 02111-1307, USA. */ | |
21341cfd | 20 | |
21341cfd | 21 | #include "config.h" |
21341cfd AS |
22 | #include "system.h" |
23 | #include "tree.h" | |
e5ecd4ea | 24 | #include "rtl.h" |
1b42a6a9 | 25 | #include "tm_p.h" |
b9bfacf0 | 26 | #include "toplev.h" |
21341cfd AS |
27 | #include "varray.h" |
28 | #include "flags.h" | |
e5ecd4ea | 29 | #include "ggc.h" |
2a9a326b | 30 | #include "timevar.h" |
e5ecd4ea | 31 | |
825b6926 ZW |
32 | /* Prefer MAP_ANON(YMOUS) to /dev/zero, since we don't need to keep a |
33 | file open. Prefer either to valloc. */ | |
34 | #ifdef HAVE_MMAP_ANON | |
35 | # undef HAVE_MMAP_DEV_ZERO | |
825b6926 ZW |
36 | |
37 | # include <sys/mman.h> | |
38 | # ifndef MAP_FAILED | |
39 | # define MAP_FAILED -1 | |
40 | # endif | |
41 | # if !defined (MAP_ANONYMOUS) && defined (MAP_ANON) | |
42 | # define MAP_ANONYMOUS MAP_ANON | |
43 | # endif | |
44 | # define USING_MMAP | |
45 | ||
005537df | 46 | #endif |
21341cfd | 47 | |
825b6926 | 48 | #ifdef HAVE_MMAP_DEV_ZERO |
825b6926 ZW |
49 | |
50 | # include <sys/mman.h> | |
51 | # ifndef MAP_FAILED | |
52 | # define MAP_FAILED -1 | |
53 | # endif | |
54 | # define USING_MMAP | |
55 | ||
8342b467 RH |
56 | #endif |
57 | ||
130fadbb RH |
58 | #ifndef USING_MMAP |
59 | #define USING_MALLOC_PAGE_GROUPS | |
5b918807 | 60 | #endif |
21341cfd AS |
61 | |
62 | /* Stategy: | |
63 | ||
64 | This garbage-collecting allocator allocates objects on one of a set | |
65 | of pages. Each page can allocate objects of a single size only; | |
66 | available sizes are powers of two starting at four bytes. The size | |
67 | of an allocation request is rounded up to the next power of two | |
68 | (`order'), and satisfied from the appropriate page. | |
69 | ||
70 | Each page is recorded in a page-entry, which also maintains an | |
71 | in-use bitmap of object positions on the page. This allows the | |
72 | allocation state of a particular object to be flipped without | |
73 | touching the page itself. | |
74 | ||
75 | Each page-entry also has a context depth, which is used to track | |
76 | pushing and popping of allocation contexts. Only objects allocated | |
77 | in the current (highest-numbered) context may be collected. | |
78 | ||
79 | Page entries are arranged in an array of singly-linked lists. The | |
80 | array is indexed by the allocation size, in bits, of the pages on | |
81 | it; i.e. all pages on a list allocate objects of the same size. | |
82 | Pages are ordered on the list such that all non-full pages precede | |
83 | all full pages, with non-full pages arranged in order of decreasing | |
84 | context depth. | |
85 | ||
86 | Empty pages (of all orders) are kept on a single page cache list, | |
87 | and are considered first when new pages are required; they are | |
88 | deallocated at the start of the next collection if they haven't | |
89 | been recycled by then. */ | |
90 | ||
91 | ||
92 | /* Define GGC_POISON to poison memory marked unused by the collector. */ | |
93 | #undef GGC_POISON | |
94 | ||
95 | /* Define GGC_ALWAYS_COLLECT to perform collection every time | |
96 | ggc_collect is invoked. Otherwise, collection is performed only | |
97 | when a significant amount of memory has been allocated since the | |
98 | last collection. */ | |
85f88abf | 99 | #undef GGC_ALWAYS_COLLECT |
21341cfd | 100 | |
f4524c9e | 101 | #ifdef ENABLE_GC_CHECKING |
21341cfd | 102 | #define GGC_POISON |
f4524c9e ZW |
103 | #endif |
104 | #ifdef ENABLE_GC_ALWAYS_COLLECT | |
21341cfd AS |
105 | #define GGC_ALWAYS_COLLECT |
106 | #endif | |
107 | ||
108 | /* Define GGC_DEBUG_LEVEL to print debugging information. | |
109 | 0: No debugging output. | |
110 | 1: GC statistics only. | |
111 | 2: Page-entry allocations/deallocations as well. | |
112 | 3: Object allocations as well. | |
6d2f8887 | 113 | 4: Object marks as well. */ |
21341cfd AS |
114 | #define GGC_DEBUG_LEVEL (0) |
115 | \f | |
116 | #ifndef HOST_BITS_PER_PTR | |
117 | #define HOST_BITS_PER_PTR HOST_BITS_PER_LONG | |
118 | #endif | |
119 | ||
21341cfd AS |
120 | \f |
121 | /* A two-level tree is used to look up the page-entry for a given | |
122 | pointer. Two chunks of the pointer's bits are extracted to index | |
123 | the first and second levels of the tree, as follows: | |
124 | ||
125 | HOST_PAGE_SIZE_BITS | |
126 | 32 | | | |
127 | msb +----------------+----+------+------+ lsb | |
128 | | | | | |
129 | PAGE_L1_BITS | | |
130 | | | | |
131 | PAGE_L2_BITS | |
132 | ||
133 | The bottommost HOST_PAGE_SIZE_BITS are ignored, since page-entry | |
134 | pages are aligned on system page boundaries. The next most | |
135 | significant PAGE_L2_BITS and PAGE_L1_BITS are the second and first | |
136 | index values in the lookup table, respectively. | |
137 | ||
005537df RH |
138 | For 32-bit architectures and the settings below, there are no |
139 | leftover bits. For architectures with wider pointers, the lookup | |
140 | tree points to a list of pages, which must be scanned to find the | |
141 | correct one. */ | |
21341cfd AS |
142 | |
143 | #define PAGE_L1_BITS (8) | |
144 | #define PAGE_L2_BITS (32 - PAGE_L1_BITS - G.lg_pagesize) | |
145 | #define PAGE_L1_SIZE ((size_t) 1 << PAGE_L1_BITS) | |
146 | #define PAGE_L2_SIZE ((size_t) 1 << PAGE_L2_BITS) | |
147 | ||
148 | #define LOOKUP_L1(p) \ | |
149 | (((size_t) (p) >> (32 - PAGE_L1_BITS)) & ((1 << PAGE_L1_BITS) - 1)) | |
150 | ||
151 | #define LOOKUP_L2(p) \ | |
152 | (((size_t) (p) >> G.lg_pagesize) & ((1 << PAGE_L2_BITS) - 1)) | |
153 | ||
2be510b8 MM |
154 | /* The number of objects per allocation page, for objects on a page of |
155 | the indicated ORDER. */ | |
156 | #define OBJECTS_PER_PAGE(ORDER) objects_per_page_table[ORDER] | |
157 | ||
158 | /* The size of an object on a page of the indicated ORDER. */ | |
159 | #define OBJECT_SIZE(ORDER) object_size_table[ORDER] | |
160 | ||
161 | /* The number of extra orders, not corresponding to power-of-two sized | |
162 | objects. */ | |
163 | ||
ca7558fc | 164 | #define NUM_EXTRA_ORDERS ARRAY_SIZE (extra_order_size_table) |
2be510b8 MM |
165 | |
166 | /* The Ith entry is the maximum size of an object to be stored in the | |
167 | Ith extra order. Adding a new entry to this array is the *only* | |
168 | thing you need to do to add a new special allocation size. */ | |
169 | ||
170 | static const size_t extra_order_size_table[] = { | |
171 | sizeof (struct tree_decl), | |
172 | sizeof (struct tree_list) | |
173 | }; | |
174 | ||
175 | /* The total number of orders. */ | |
176 | ||
177 | #define NUM_ORDERS (HOST_BITS_PER_PTR + NUM_EXTRA_ORDERS) | |
178 | ||
b1095f9c MM |
179 | /* We use this structure to determine the alignment required for |
180 | allocations. For power-of-two sized allocations, that's not a | |
181 | problem, but it does matter for odd-sized allocations. */ | |
182 | ||
183 | struct max_alignment { | |
184 | char c; | |
185 | union { | |
186 | HOST_WIDEST_INT i; | |
187 | #ifdef HAVE_LONG_DOUBLE | |
188 | long double d; | |
189 | #else | |
190 | double d; | |
191 | #endif | |
192 | } u; | |
193 | }; | |
194 | ||
195 | /* The biggest alignment required. */ | |
196 | ||
197 | #define MAX_ALIGNMENT (offsetof (struct max_alignment, u)) | |
198 | ||
2be510b8 MM |
199 | /* The Ith entry is the number of objects on a page or order I. */ |
200 | ||
201 | static unsigned objects_per_page_table[NUM_ORDERS]; | |
202 | ||
203 | /* The Ith entry is the size of an object on a page of order I. */ | |
204 | ||
205 | static size_t object_size_table[NUM_ORDERS]; | |
21341cfd AS |
206 | |
207 | /* A page_entry records the status of an allocation page. This | |
208 | structure is dynamically sized to fit the bitmap in_use_p. */ | |
209 | typedef struct page_entry | |
210 | { | |
211 | /* The next page-entry with objects of the same size, or NULL if | |
212 | this is the last page-entry. */ | |
213 | struct page_entry *next; | |
214 | ||
215 | /* The number of bytes allocated. (This will always be a multiple | |
216 | of the host system page size.) */ | |
217 | size_t bytes; | |
218 | ||
219 | /* The address at which the memory is allocated. */ | |
220 | char *page; | |
221 | ||
130fadbb RH |
222 | #ifdef USING_MALLOC_PAGE_GROUPS |
223 | /* Back pointer to the page group this page came from. */ | |
224 | struct page_group *group; | |
225 | #endif | |
226 | ||
21341cfd AS |
227 | /* Saved in-use bit vector for pages that aren't in the topmost |
228 | context during collection. */ | |
229 | unsigned long *save_in_use_p; | |
230 | ||
231 | /* Context depth of this page. */ | |
ae373eda | 232 | unsigned short context_depth; |
21341cfd AS |
233 | |
234 | /* The number of free objects remaining on this page. */ | |
235 | unsigned short num_free_objects; | |
236 | ||
237 | /* A likely candidate for the bit position of a free object for the | |
238 | next allocation from this page. */ | |
239 | unsigned short next_bit_hint; | |
240 | ||
ae373eda MM |
241 | /* The lg of size of objects allocated from this page. */ |
242 | unsigned char order; | |
243 | ||
21341cfd AS |
244 | /* A bit vector indicating whether or not objects are in use. The |
245 | Nth bit is one if the Nth object on this page is allocated. This | |
246 | array is dynamically sized. */ | |
247 | unsigned long in_use_p[1]; | |
248 | } page_entry; | |
249 | ||
130fadbb RH |
250 | #ifdef USING_MALLOC_PAGE_GROUPS |
251 | /* A page_group describes a large allocation from malloc, from which | |
252 | we parcel out aligned pages. */ | |
253 | typedef struct page_group | |
254 | { | |
255 | /* A linked list of all extant page groups. */ | |
256 | struct page_group *next; | |
257 | ||
258 | /* The address we received from malloc. */ | |
259 | char *allocation; | |
260 | ||
261 | /* The size of the block. */ | |
262 | size_t alloc_size; | |
263 | ||
264 | /* A bitmask of pages in use. */ | |
265 | unsigned int in_use; | |
266 | } page_group; | |
267 | #endif | |
21341cfd AS |
268 | |
269 | #if HOST_BITS_PER_PTR <= 32 | |
270 | ||
271 | /* On 32-bit hosts, we use a two level page table, as pictured above. */ | |
272 | typedef page_entry **page_table[PAGE_L1_SIZE]; | |
273 | ||
274 | #else | |
275 | ||
005537df RH |
276 | /* On 64-bit hosts, we use the same two level page tables plus a linked |
277 | list that disambiguates the top 32-bits. There will almost always be | |
21341cfd AS |
278 | exactly one entry in the list. */ |
279 | typedef struct page_table_chain | |
280 | { | |
281 | struct page_table_chain *next; | |
282 | size_t high_bits; | |
283 | page_entry **table[PAGE_L1_SIZE]; | |
284 | } *page_table; | |
285 | ||
286 | #endif | |
287 | ||
288 | /* The rest of the global variables. */ | |
289 | static struct globals | |
290 | { | |
291 | /* The Nth element in this array is a page with objects of size 2^N. | |
292 | If there are any pages with free objects, they will be at the | |
293 | head of the list. NULL if there are no page-entries for this | |
294 | object size. */ | |
2be510b8 | 295 | page_entry *pages[NUM_ORDERS]; |
21341cfd AS |
296 | |
297 | /* The Nth element in this array is the last page with objects of | |
298 | size 2^N. NULL if there are no page-entries for this object | |
299 | size. */ | |
2be510b8 | 300 | page_entry *page_tails[NUM_ORDERS]; |
21341cfd AS |
301 | |
302 | /* Lookup table for associating allocation pages with object addresses. */ | |
303 | page_table lookup; | |
304 | ||
305 | /* The system's page size. */ | |
306 | size_t pagesize; | |
307 | size_t lg_pagesize; | |
308 | ||
309 | /* Bytes currently allocated. */ | |
310 | size_t allocated; | |
311 | ||
312 | /* Bytes currently allocated at the end of the last collection. */ | |
313 | size_t allocated_last_gc; | |
314 | ||
3277221c MM |
315 | /* Total amount of memory mapped. */ |
316 | size_t bytes_mapped; | |
317 | ||
21341cfd | 318 | /* The current depth in the context stack. */ |
d416576b | 319 | unsigned short context_depth; |
21341cfd AS |
320 | |
321 | /* A file descriptor open to /dev/zero for reading. */ | |
825b6926 | 322 | #if defined (HAVE_MMAP_DEV_ZERO) |
21341cfd AS |
323 | int dev_zero_fd; |
324 | #endif | |
325 | ||
326 | /* A cache of free system pages. */ | |
327 | page_entry *free_pages; | |
328 | ||
130fadbb RH |
329 | #ifdef USING_MALLOC_PAGE_GROUPS |
330 | page_group *page_groups; | |
331 | #endif | |
332 | ||
21341cfd AS |
333 | /* The file descriptor for debugging output. */ |
334 | FILE *debug_file; | |
335 | } G; | |
336 | ||
21341cfd AS |
337 | /* The size in bytes required to maintain a bitmap for the objects |
338 | on a page-entry. */ | |
339 | #define BITMAP_SIZE(Num_objects) \ | |
2be510b8 | 340 | (CEIL ((Num_objects), HOST_BITS_PER_LONG) * sizeof(long)) |
21341cfd AS |
341 | |
342 | /* Skip garbage collection if the current allocation is not at least | |
343 | this factor times the allocation at the end of the last collection. | |
344 | In other words, total allocation must expand by (this factor minus | |
345 | one) before collection is performed. */ | |
346 | #define GGC_MIN_EXPAND_FOR_GC (1.3) | |
347 | ||
a70261ee RH |
348 | /* Bound `allocated_last_gc' to 4MB, to prevent the memory expansion |
349 | test from triggering too often when the heap is small. */ | |
350 | #define GGC_MIN_LAST_ALLOCATED (4 * 1024 * 1024) | |
351 | ||
130fadbb RH |
352 | /* Allocate pages in chunks of this size, to throttle calls to memory |
353 | allocation routines. The first page is used, the rest go onto the | |
354 | free list. This cannot be larger than HOST_BITS_PER_INT for the | |
355 | in_use bitmask for page_group. */ | |
054f5e69 | 356 | #define GGC_QUIRE_SIZE 16 |
21341cfd | 357 | \f |
3fe41456 KG |
358 | static int ggc_allocated_p PARAMS ((const void *)); |
359 | static page_entry *lookup_page_table_entry PARAMS ((const void *)); | |
360 | static void set_page_table_entry PARAMS ((void *, page_entry *)); | |
130fadbb | 361 | #ifdef USING_MMAP |
3fe41456 | 362 | static char *alloc_anon PARAMS ((char *, size_t)); |
130fadbb RH |
363 | #endif |
364 | #ifdef USING_MALLOC_PAGE_GROUPS | |
365 | static size_t page_group_index PARAMS ((char *, char *)); | |
366 | static void set_page_group_in_use PARAMS ((page_group *, char *)); | |
367 | static void clear_page_group_in_use PARAMS ((page_group *, char *)); | |
368 | #endif | |
3fe41456 KG |
369 | static struct page_entry * alloc_page PARAMS ((unsigned)); |
370 | static void free_page PARAMS ((struct page_entry *)); | |
371 | static void release_pages PARAMS ((void)); | |
372 | static void clear_marks PARAMS ((void)); | |
373 | static void sweep_pages PARAMS ((void)); | |
374 | static void ggc_recalculate_in_use_p PARAMS ((page_entry *)); | |
21341cfd AS |
375 | |
376 | #ifdef GGC_POISON | |
3fe41456 | 377 | static void poison_pages PARAMS ((void)); |
21341cfd AS |
378 | #endif |
379 | ||
3fe41456 | 380 | void debug_print_page_list PARAMS ((int)); |
21341cfd | 381 | \f |
005537df | 382 | /* Returns non-zero if P was allocated in GC'able memory. */ |
21341cfd | 383 | |
005537df RH |
384 | static inline int |
385 | ggc_allocated_p (p) | |
386 | const void *p; | |
21341cfd AS |
387 | { |
388 | page_entry ***base; | |
005537df | 389 | size_t L1, L2; |
21341cfd AS |
390 | |
391 | #if HOST_BITS_PER_PTR <= 32 | |
392 | base = &G.lookup[0]; | |
393 | #else | |
394 | page_table table = G.lookup; | |
395 | size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff; | |
005537df RH |
396 | while (1) |
397 | { | |
398 | if (table == NULL) | |
399 | return 0; | |
400 | if (table->high_bits == high_bits) | |
401 | break; | |
402 | table = table->next; | |
403 | } | |
21341cfd AS |
404 | base = &table->table[0]; |
405 | #endif | |
406 | ||
eaec9b3d | 407 | /* Extract the level 1 and 2 indices. */ |
74c937ca MM |
408 | L1 = LOOKUP_L1 (p); |
409 | L2 = LOOKUP_L2 (p); | |
410 | ||
411 | return base[L1] && base[L1][L2]; | |
412 | } | |
413 | ||
414 | /* Traverse the page table and find the entry for a page. | |
415 | Die (probably) if the object wasn't allocated via GC. */ | |
416 | ||
417 | static inline page_entry * | |
418 | lookup_page_table_entry(p) | |
005537df | 419 | const void *p; |
74c937ca MM |
420 | { |
421 | page_entry ***base; | |
422 | size_t L1, L2; | |
423 | ||
005537df RH |
424 | #if HOST_BITS_PER_PTR <= 32 |
425 | base = &G.lookup[0]; | |
426 | #else | |
427 | page_table table = G.lookup; | |
428 | size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff; | |
429 | while (table->high_bits != high_bits) | |
430 | table = table->next; | |
431 | base = &table->table[0]; | |
432 | #endif | |
74c937ca | 433 | |
eaec9b3d | 434 | /* Extract the level 1 and 2 indices. */ |
21341cfd AS |
435 | L1 = LOOKUP_L1 (p); |
436 | L2 = LOOKUP_L2 (p); | |
437 | ||
438 | return base[L1][L2]; | |
439 | } | |
440 | ||
21341cfd | 441 | /* Set the page table entry for a page. */ |
cb2ec151 | 442 | |
21341cfd AS |
443 | static void |
444 | set_page_table_entry(p, entry) | |
445 | void *p; | |
446 | page_entry *entry; | |
447 | { | |
448 | page_entry ***base; | |
449 | size_t L1, L2; | |
450 | ||
451 | #if HOST_BITS_PER_PTR <= 32 | |
452 | base = &G.lookup[0]; | |
453 | #else | |
454 | page_table table; | |
455 | size_t high_bits = (size_t) p & ~ (size_t) 0xffffffff; | |
456 | for (table = G.lookup; table; table = table->next) | |
457 | if (table->high_bits == high_bits) | |
458 | goto found; | |
459 | ||
460 | /* Not found -- allocate a new table. */ | |
461 | table = (page_table) xcalloc (1, sizeof(*table)); | |
462 | table->next = G.lookup; | |
463 | table->high_bits = high_bits; | |
464 | G.lookup = table; | |
465 | found: | |
466 | base = &table->table[0]; | |
467 | #endif | |
468 | ||
eaec9b3d | 469 | /* Extract the level 1 and 2 indices. */ |
21341cfd AS |
470 | L1 = LOOKUP_L1 (p); |
471 | L2 = LOOKUP_L2 (p); | |
472 | ||
473 | if (base[L1] == NULL) | |
474 | base[L1] = (page_entry **) xcalloc (PAGE_L2_SIZE, sizeof (page_entry *)); | |
475 | ||
476 | base[L1][L2] = entry; | |
477 | } | |
478 | ||
21341cfd | 479 | /* Prints the page-entry for object size ORDER, for debugging. */ |
cb2ec151 | 480 | |
21341cfd AS |
481 | void |
482 | debug_print_page_list (order) | |
483 | int order; | |
484 | { | |
485 | page_entry *p; | |
683eb0e9 JM |
486 | printf ("Head=%p, Tail=%p:\n", (PTR) G.pages[order], |
487 | (PTR) G.page_tails[order]); | |
21341cfd AS |
488 | p = G.pages[order]; |
489 | while (p != NULL) | |
490 | { | |
683eb0e9 JM |
491 | printf ("%p(%1d|%3d) -> ", (PTR) p, p->context_depth, |
492 | p->num_free_objects); | |
21341cfd AS |
493 | p = p->next; |
494 | } | |
495 | printf ("NULL\n"); | |
496 | fflush (stdout); | |
497 | } | |
498 | ||
130fadbb | 499 | #ifdef USING_MMAP |
21341cfd | 500 | /* Allocate SIZE bytes of anonymous memory, preferably near PREF, |
825b6926 ZW |
501 | (if non-null). The ifdef structure here is intended to cause a |
502 | compile error unless exactly one of the HAVE_* is defined. */ | |
cb2ec151 | 503 | |
21341cfd AS |
504 | static inline char * |
505 | alloc_anon (pref, size) | |
005537df | 506 | char *pref ATTRIBUTE_UNUSED; |
21341cfd AS |
507 | size_t size; |
508 | { | |
825b6926 ZW |
509 | #ifdef HAVE_MMAP_ANON |
510 | char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE, | |
511 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
512 | #endif | |
513 | #ifdef HAVE_MMAP_DEV_ZERO | |
514 | char *page = (char *) mmap (pref, size, PROT_READ | PROT_WRITE, | |
515 | MAP_PRIVATE, G.dev_zero_fd, 0); | |
21341cfd | 516 | #endif |
825b6926 ZW |
517 | |
518 | if (page == (char *) MAP_FAILED) | |
005537df | 519 | { |
1f978f5f | 520 | perror ("virtual memory exhausted"); |
bd0f0717 | 521 | exit (FATAL_EXIT_CODE); |
005537df | 522 | } |
21341cfd | 523 | |
3277221c MM |
524 | /* Remember that we allocated this memory. */ |
525 | G.bytes_mapped += size; | |
526 | ||
21341cfd AS |
527 | return page; |
528 | } | |
130fadbb RH |
529 | #endif |
530 | #ifdef USING_MALLOC_PAGE_GROUPS | |
531 | /* Compute the index for this page into the page group. */ | |
532 | ||
533 | static inline size_t | |
534 | page_group_index (allocation, page) | |
535 | char *allocation, *page; | |
536 | { | |
c4f2c499 | 537 | return (size_t) (page - allocation) >> G.lg_pagesize; |
130fadbb RH |
538 | } |
539 | ||
540 | /* Set and clear the in_use bit for this page in the page group. */ | |
541 | ||
542 | static inline void | |
543 | set_page_group_in_use (group, page) | |
544 | page_group *group; | |
545 | char *page; | |
546 | { | |
547 | group->in_use |= 1 << page_group_index (group->allocation, page); | |
548 | } | |
549 | ||
550 | static inline void | |
551 | clear_page_group_in_use (group, page) | |
552 | page_group *group; | |
553 | char *page; | |
554 | { | |
555 | group->in_use &= ~(1 << page_group_index (group->allocation, page)); | |
556 | } | |
557 | #endif | |
21341cfd AS |
558 | |
559 | /* Allocate a new page for allocating objects of size 2^ORDER, | |
560 | and return an entry for it. The entry is not added to the | |
561 | appropriate page_table list. */ | |
cb2ec151 | 562 | |
21341cfd AS |
563 | static inline struct page_entry * |
564 | alloc_page (order) | |
565 | unsigned order; | |
566 | { | |
567 | struct page_entry *entry, *p, **pp; | |
568 | char *page; | |
569 | size_t num_objects; | |
570 | size_t bitmap_size; | |
571 | size_t page_entry_size; | |
572 | size_t entry_size; | |
130fadbb RH |
573 | #ifdef USING_MALLOC_PAGE_GROUPS |
574 | page_group *group; | |
575 | #endif | |
21341cfd AS |
576 | |
577 | num_objects = OBJECTS_PER_PAGE (order); | |
578 | bitmap_size = BITMAP_SIZE (num_objects + 1); | |
579 | page_entry_size = sizeof (page_entry) - sizeof (long) + bitmap_size; | |
2be510b8 | 580 | entry_size = num_objects * OBJECT_SIZE (order); |
ca79429a RH |
581 | if (entry_size < G.pagesize) |
582 | entry_size = G.pagesize; | |
21341cfd AS |
583 | |
584 | entry = NULL; | |
585 | page = NULL; | |
586 | ||
587 | /* Check the list of free pages for one we can use. */ | |
bd0f0717 | 588 | for (pp = &G.free_pages, p = *pp; p; pp = &p->next, p = *pp) |
21341cfd AS |
589 | if (p->bytes == entry_size) |
590 | break; | |
591 | ||
592 | if (p != NULL) | |
593 | { | |
dc297297 | 594 | /* Recycle the allocated memory from this page ... */ |
21341cfd AS |
595 | *pp = p->next; |
596 | page = p->page; | |
bd0f0717 | 597 | |
130fadbb RH |
598 | #ifdef USING_MALLOC_PAGE_GROUPS |
599 | group = p->group; | |
600 | #endif | |
bd0f0717 | 601 | |
21341cfd AS |
602 | /* ... and, if possible, the page entry itself. */ |
603 | if (p->order == order) | |
604 | { | |
605 | entry = p; | |
606 | memset (entry, 0, page_entry_size); | |
607 | } | |
608 | else | |
609 | free (p); | |
610 | } | |
825b6926 | 611 | #ifdef USING_MMAP |
054f5e69 | 612 | else if (entry_size == G.pagesize) |
21341cfd | 613 | { |
054f5e69 ZW |
614 | /* We want just one page. Allocate a bunch of them and put the |
615 | extras on the freelist. (Can only do this optimization with | |
616 | mmap for backing store.) */ | |
617 | struct page_entry *e, *f = G.free_pages; | |
618 | int i; | |
619 | ||
ca79429a | 620 | page = alloc_anon (NULL, G.pagesize * GGC_QUIRE_SIZE); |
bd0f0717 | 621 | |
054f5e69 ZW |
622 | /* This loop counts down so that the chain will be in ascending |
623 | memory order. */ | |
624 | for (i = GGC_QUIRE_SIZE - 1; i >= 1; i--) | |
625 | { | |
ca79429a RH |
626 | e = (struct page_entry *) xcalloc (1, page_entry_size); |
627 | e->order = order; | |
628 | e->bytes = G.pagesize; | |
629 | e->page = page + (i << G.lg_pagesize); | |
054f5e69 ZW |
630 | e->next = f; |
631 | f = e; | |
632 | } | |
bd0f0717 | 633 | |
054f5e69 | 634 | G.free_pages = f; |
21341cfd | 635 | } |
054f5e69 ZW |
636 | else |
637 | page = alloc_anon (NULL, entry_size); | |
130fadbb RH |
638 | #endif |
639 | #ifdef USING_MALLOC_PAGE_GROUPS | |
640 | else | |
641 | { | |
642 | /* Allocate a large block of memory and serve out the aligned | |
643 | pages therein. This results in much less memory wastage | |
644 | than the traditional implementation of valloc. */ | |
645 | ||
646 | char *allocation, *a, *enda; | |
647 | size_t alloc_size, head_slop, tail_slop; | |
648 | int multiple_pages = (entry_size == G.pagesize); | |
649 | ||
650 | if (multiple_pages) | |
651 | alloc_size = GGC_QUIRE_SIZE * G.pagesize; | |
652 | else | |
653 | alloc_size = entry_size + G.pagesize - 1; | |
654 | allocation = xmalloc (alloc_size); | |
655 | ||
c4f2c499 | 656 | page = (char *) (((size_t) allocation + G.pagesize - 1) & -G.pagesize); |
130fadbb RH |
657 | head_slop = page - allocation; |
658 | if (multiple_pages) | |
659 | tail_slop = ((size_t) allocation + alloc_size) & (G.pagesize - 1); | |
660 | else | |
661 | tail_slop = alloc_size - entry_size - head_slop; | |
662 | enda = allocation + alloc_size - tail_slop; | |
663 | ||
664 | /* We allocated N pages, which are likely not aligned, leaving | |
665 | us with N-1 usable pages. We plan to place the page_group | |
666 | structure somewhere in the slop. */ | |
667 | if (head_slop >= sizeof (page_group)) | |
668 | group = (page_group *)page - 1; | |
669 | else | |
670 | { | |
671 | /* We magically got an aligned allocation. Too bad, we have | |
672 | to waste a page anyway. */ | |
673 | if (tail_slop == 0) | |
674 | { | |
675 | enda -= G.pagesize; | |
676 | tail_slop += G.pagesize; | |
677 | } | |
678 | if (tail_slop < sizeof (page_group)) | |
679 | abort (); | |
680 | group = (page_group *)enda; | |
681 | tail_slop -= sizeof (page_group); | |
682 | } | |
683 | ||
684 | /* Remember that we allocated this memory. */ | |
685 | group->next = G.page_groups; | |
686 | group->allocation = allocation; | |
687 | group->alloc_size = alloc_size; | |
688 | group->in_use = 0; | |
689 | G.page_groups = group; | |
690 | G.bytes_mapped += alloc_size; | |
691 | ||
692 | /* If we allocated multiple pages, put the rest on the free list. */ | |
693 | if (multiple_pages) | |
694 | { | |
695 | struct page_entry *e, *f = G.free_pages; | |
696 | for (a = enda - G.pagesize; a != page; a -= G.pagesize) | |
697 | { | |
698 | e = (struct page_entry *) xcalloc (1, page_entry_size); | |
699 | e->order = order; | |
700 | e->bytes = G.pagesize; | |
701 | e->page = a; | |
702 | e->group = group; | |
703 | e->next = f; | |
704 | f = e; | |
705 | } | |
706 | G.free_pages = f; | |
707 | } | |
708 | } | |
709 | #endif | |
21341cfd AS |
710 | |
711 | if (entry == NULL) | |
712 | entry = (struct page_entry *) xcalloc (1, page_entry_size); | |
713 | ||
714 | entry->bytes = entry_size; | |
715 | entry->page = page; | |
716 | entry->context_depth = G.context_depth; | |
717 | entry->order = order; | |
718 | entry->num_free_objects = num_objects; | |
719 | entry->next_bit_hint = 1; | |
720 | ||
130fadbb RH |
721 | #ifdef USING_MALLOC_PAGE_GROUPS |
722 | entry->group = group; | |
723 | set_page_group_in_use (group, page); | |
724 | #endif | |
725 | ||
21341cfd AS |
726 | /* Set the one-past-the-end in-use bit. This acts as a sentry as we |
727 | increment the hint. */ | |
728 | entry->in_use_p[num_objects / HOST_BITS_PER_LONG] | |
729 | = (unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG); | |
730 | ||
731 | set_page_table_entry (page, entry); | |
732 | ||
733 | if (GGC_DEBUG_LEVEL >= 2) | |
734 | fprintf (G.debug_file, | |
bd0f0717 RK |
735 | "Allocating page at %p, object size=%ld, data %p-%p\n", |
736 | (PTR) entry, (long) OBJECT_SIZE (order), page, | |
737 | page + entry_size - 1); | |
21341cfd AS |
738 | |
739 | return entry; | |
740 | } | |
741 | ||
cb2ec151 | 742 | /* For a page that is no longer needed, put it on the free page list. */ |
21341cfd | 743 | |
21341cfd AS |
744 | static inline void |
745 | free_page (entry) | |
746 | page_entry *entry; | |
747 | { | |
748 | if (GGC_DEBUG_LEVEL >= 2) | |
749 | fprintf (G.debug_file, | |
683eb0e9 | 750 | "Deallocating page at %p, data %p-%p\n", (PTR) entry, |
21341cfd AS |
751 | entry->page, entry->page + entry->bytes - 1); |
752 | ||
753 | set_page_table_entry (entry->page, NULL); | |
754 | ||
130fadbb RH |
755 | #ifdef USING_MALLOC_PAGE_GROUPS |
756 | clear_page_group_in_use (entry->group, entry->page); | |
757 | #endif | |
758 | ||
21341cfd AS |
759 | entry->next = G.free_pages; |
760 | G.free_pages = entry; | |
761 | } | |
762 | ||
cb2ec151 | 763 | /* Release the free page cache to the system. */ |
21341cfd | 764 | |
4934cc53 | 765 | static void |
21341cfd AS |
766 | release_pages () |
767 | { | |
825b6926 | 768 | #ifdef USING_MMAP |
130fadbb | 769 | page_entry *p, *next; |
21341cfd AS |
770 | char *start; |
771 | size_t len; | |
772 | ||
054f5e69 | 773 | /* Gather up adjacent pages so they are unmapped together. */ |
21341cfd | 774 | p = G.free_pages; |
21341cfd AS |
775 | |
776 | while (p) | |
777 | { | |
054f5e69 | 778 | start = p->page; |
21341cfd | 779 | next = p->next; |
054f5e69 | 780 | len = p->bytes; |
21341cfd AS |
781 | free (p); |
782 | p = next; | |
21341cfd | 783 | |
054f5e69 ZW |
784 | while (p && p->page == start + len) |
785 | { | |
786 | next = p->next; | |
787 | len += p->bytes; | |
788 | free (p); | |
789 | p = next; | |
790 | } | |
791 | ||
792 | munmap (start, len); | |
793 | G.bytes_mapped -= len; | |
794 | } | |
005537df | 795 | |
21341cfd | 796 | G.free_pages = NULL; |
130fadbb RH |
797 | #endif |
798 | #ifdef USING_MALLOC_PAGE_GROUPS | |
799 | page_entry **pp, *p; | |
800 | page_group **gp, *g; | |
801 | ||
802 | /* Remove all pages from free page groups from the list. */ | |
803 | pp = &G.free_pages; | |
804 | while ((p = *pp) != NULL) | |
805 | if (p->group->in_use == 0) | |
806 | { | |
807 | *pp = p->next; | |
808 | free (p); | |
809 | } | |
810 | else | |
811 | pp = &p->next; | |
812 | ||
813 | /* Remove all free page groups, and release the storage. */ | |
814 | gp = &G.page_groups; | |
815 | while ((g = *gp) != NULL) | |
816 | if (g->in_use == 0) | |
817 | { | |
818 | *gp = g->next; | |
819 | G.bytes_mapped -= g->alloc_size; | |
820 | free (g->allocation); | |
821 | } | |
822 | else | |
823 | gp = &g->next; | |
824 | #endif | |
21341cfd AS |
825 | } |
826 | ||
21341cfd | 827 | /* This table provides a fast way to determine ceil(log_2(size)) for |
9fd51e67 | 828 | allocation requests. The minimum allocation size is eight bytes. */ |
cb2ec151 | 829 | |
2be510b8 | 830 | static unsigned char size_lookup[257] = |
9fd51e67 ZW |
831 | { |
832 | 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, | |
21341cfd AS |
833 | 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, |
834 | 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, | |
835 | 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, | |
836 | 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, | |
837 | 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, | |
838 | 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, | |
839 | 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, | |
840 | 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
841 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
842 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
843 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
844 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
845 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
846 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
847 | 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, | |
848 | 8 | |
849 | }; | |
850 | ||
851 | /* Allocate a chunk of memory of SIZE bytes. If ZERO is non-zero, the | |
852 | memory is zeroed; otherwise, its contents are undefined. */ | |
cb2ec151 | 853 | |
005537df | 854 | void * |
f8a83ee3 | 855 | ggc_alloc (size) |
21341cfd | 856 | size_t size; |
21341cfd AS |
857 | { |
858 | unsigned order, word, bit, object_offset; | |
859 | struct page_entry *entry; | |
860 | void *result; | |
861 | ||
862 | if (size <= 256) | |
863 | order = size_lookup[size]; | |
864 | else | |
865 | { | |
866 | order = 9; | |
2be510b8 | 867 | while (size > OBJECT_SIZE (order)) |
21341cfd AS |
868 | order++; |
869 | } | |
870 | ||
871 | /* If there are non-full pages for this size allocation, they are at | |
872 | the head of the list. */ | |
873 | entry = G.pages[order]; | |
874 | ||
875 | /* If there is no page for this object size, or all pages in this | |
876 | context are full, allocate a new page. */ | |
4934cc53 | 877 | if (entry == NULL || entry->num_free_objects == 0) |
21341cfd AS |
878 | { |
879 | struct page_entry *new_entry; | |
880 | new_entry = alloc_page (order); | |
881 | ||
882 | /* If this is the only entry, it's also the tail. */ | |
883 | if (entry == NULL) | |
884 | G.page_tails[order] = new_entry; | |
885 | ||
886 | /* Put new pages at the head of the page list. */ | |
887 | new_entry->next = entry; | |
888 | entry = new_entry; | |
889 | G.pages[order] = new_entry; | |
890 | ||
891 | /* For a new page, we know the word and bit positions (in the | |
892 | in_use bitmap) of the first available object -- they're zero. */ | |
893 | new_entry->next_bit_hint = 1; | |
894 | word = 0; | |
895 | bit = 0; | |
896 | object_offset = 0; | |
897 | } | |
898 | else | |
899 | { | |
900 | /* First try to use the hint left from the previous allocation | |
901 | to locate a clear bit in the in-use bitmap. We've made sure | |
902 | that the one-past-the-end bit is always set, so if the hint | |
903 | has run over, this test will fail. */ | |
904 | unsigned hint = entry->next_bit_hint; | |
905 | word = hint / HOST_BITS_PER_LONG; | |
906 | bit = hint % HOST_BITS_PER_LONG; | |
907 | ||
908 | /* If the hint didn't work, scan the bitmap from the beginning. */ | |
909 | if ((entry->in_use_p[word] >> bit) & 1) | |
910 | { | |
911 | word = bit = 0; | |
912 | while (~entry->in_use_p[word] == 0) | |
913 | ++word; | |
914 | while ((entry->in_use_p[word] >> bit) & 1) | |
915 | ++bit; | |
916 | hint = word * HOST_BITS_PER_LONG + bit; | |
917 | } | |
918 | ||
919 | /* Next time, try the next bit. */ | |
920 | entry->next_bit_hint = hint + 1; | |
921 | ||
2be510b8 | 922 | object_offset = hint * OBJECT_SIZE (order); |
21341cfd AS |
923 | } |
924 | ||
925 | /* Set the in-use bit. */ | |
926 | entry->in_use_p[word] |= ((unsigned long) 1 << bit); | |
927 | ||
928 | /* Keep a running total of the number of free objects. If this page | |
929 | fills up, we may have to move it to the end of the list if the | |
930 | next page isn't full. If the next page is full, all subsequent | |
931 | pages are full, so there's no need to move it. */ | |
932 | if (--entry->num_free_objects == 0 | |
933 | && entry->next != NULL | |
934 | && entry->next->num_free_objects > 0) | |
935 | { | |
936 | G.pages[order] = entry->next; | |
937 | entry->next = NULL; | |
938 | G.page_tails[order]->next = entry; | |
939 | G.page_tails[order] = entry; | |
940 | } | |
941 | ||
942 | /* Calculate the object's address. */ | |
943 | result = entry->page + object_offset; | |
944 | ||
945 | #ifdef GGC_POISON | |
f8a83ee3 ZW |
946 | /* `Poison' the entire allocated object, including any padding at |
947 | the end. */ | |
2be510b8 | 948 | memset (result, 0xaf, OBJECT_SIZE (order)); |
21341cfd | 949 | #endif |
cb2ec151 | 950 | |
21341cfd AS |
951 | /* Keep track of how many bytes are being allocated. This |
952 | information is used in deciding when to collect. */ | |
2be510b8 | 953 | G.allocated += OBJECT_SIZE (order); |
21341cfd AS |
954 | |
955 | if (GGC_DEBUG_LEVEL >= 3) | |
956 | fprintf (G.debug_file, | |
bd0f0717 RK |
957 | "Allocating object, requested size=%ld, actual=%ld at %p on %p\n", |
958 | (long) size, (long) OBJECT_SIZE (order), result, (PTR) entry); | |
21341cfd AS |
959 | |
960 | return result; | |
961 | } | |
962 | ||
cb2ec151 | 963 | /* If P is not marked, marks it and return false. Otherwise return true. |
21341cfd AS |
964 | P must have been allocated by the GC allocator; it mustn't point to |
965 | static objects, stack variables, or memory allocated with malloc. */ | |
cb2ec151 | 966 | |
005537df RH |
967 | int |
968 | ggc_set_mark (p) | |
3cce094d | 969 | const void *p; |
21341cfd AS |
970 | { |
971 | page_entry *entry; | |
972 | unsigned bit, word; | |
973 | unsigned long mask; | |
974 | ||
975 | /* Look up the page on which the object is alloced. If the object | |
976 | wasn't allocated by the collector, we'll probably die. */ | |
74c937ca | 977 | entry = lookup_page_table_entry (p); |
21341cfd AS |
978 | #ifdef ENABLE_CHECKING |
979 | if (entry == NULL) | |
980 | abort (); | |
981 | #endif | |
982 | ||
983 | /* Calculate the index of the object on the page; this is its bit | |
984 | position in the in_use_p bitmap. */ | |
2be510b8 | 985 | bit = (((const char *) p) - entry->page) / OBJECT_SIZE (entry->order); |
21341cfd AS |
986 | word = bit / HOST_BITS_PER_LONG; |
987 | mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG); | |
988 | ||
dc297297 | 989 | /* If the bit was previously set, skip it. */ |
21341cfd AS |
990 | if (entry->in_use_p[word] & mask) |
991 | return 1; | |
992 | ||
993 | /* Otherwise set it, and decrement the free object count. */ | |
994 | entry->in_use_p[word] |= mask; | |
995 | entry->num_free_objects -= 1; | |
996 | ||
21341cfd AS |
997 | if (GGC_DEBUG_LEVEL >= 4) |
998 | fprintf (G.debug_file, "Marking %p\n", p); | |
999 | ||
1000 | return 0; | |
1001 | } | |
1002 | ||
4c160717 RK |
1003 | /* Return 1 if P has been marked, zero otherwise. |
1004 | P must have been allocated by the GC allocator; it mustn't point to | |
1005 | static objects, stack variables, or memory allocated with malloc. */ | |
1006 | ||
1007 | int | |
1008 | ggc_marked_p (p) | |
1009 | const void *p; | |
1010 | { | |
1011 | page_entry *entry; | |
1012 | unsigned bit, word; | |
1013 | unsigned long mask; | |
1014 | ||
1015 | /* Look up the page on which the object is alloced. If the object | |
1016 | wasn't allocated by the collector, we'll probably die. */ | |
1017 | entry = lookup_page_table_entry (p); | |
1018 | #ifdef ENABLE_CHECKING | |
1019 | if (entry == NULL) | |
1020 | abort (); | |
1021 | #endif | |
1022 | ||
1023 | /* Calculate the index of the object on the page; this is its bit | |
1024 | position in the in_use_p bitmap. */ | |
1025 | bit = (((const char *) p) - entry->page) / OBJECT_SIZE (entry->order); | |
1026 | word = bit / HOST_BITS_PER_LONG; | |
1027 | mask = (unsigned long) 1 << (bit % HOST_BITS_PER_LONG); | |
1028 | ||
a4b5b2ae | 1029 | return (entry->in_use_p[word] & mask) != 0; |
4c160717 RK |
1030 | } |
1031 | ||
cb2ec151 RH |
1032 | /* Return the size of the gc-able object P. */ |
1033 | ||
3277221c MM |
1034 | size_t |
1035 | ggc_get_size (p) | |
3cce094d | 1036 | const void *p; |
3277221c MM |
1037 | { |
1038 | page_entry *pe = lookup_page_table_entry (p); | |
2be510b8 | 1039 | return OBJECT_SIZE (pe->order); |
3277221c | 1040 | } |
21341cfd AS |
1041 | \f |
1042 | /* Initialize the ggc-mmap allocator. */ | |
cb2ec151 | 1043 | |
21341cfd AS |
1044 | void |
1045 | init_ggc () | |
1046 | { | |
2be510b8 MM |
1047 | unsigned order; |
1048 | ||
21341cfd AS |
1049 | G.pagesize = getpagesize(); |
1050 | G.lg_pagesize = exact_log2 (G.pagesize); | |
1051 | ||
825b6926 | 1052 | #ifdef HAVE_MMAP_DEV_ZERO |
21341cfd AS |
1053 | G.dev_zero_fd = open ("/dev/zero", O_RDONLY); |
1054 | if (G.dev_zero_fd == -1) | |
1055 | abort (); | |
1056 | #endif | |
1057 | ||
1058 | #if 0 | |
1059 | G.debug_file = fopen ("ggc-mmap.debug", "w"); | |
1060 | #else | |
1061 | G.debug_file = stdout; | |
1062 | #endif | |
1063 | ||
a70261ee | 1064 | G.allocated_last_gc = GGC_MIN_LAST_ALLOCATED; |
21341cfd | 1065 | |
825b6926 | 1066 | #ifdef USING_MMAP |
1b3e1423 RH |
1067 | /* StunOS has an amazing off-by-one error for the first mmap allocation |
1068 | after fiddling with RLIMIT_STACK. The result, as hard as it is to | |
1069 | believe, is an unaligned page allocation, which would cause us to | |
1070 | hork badly if we tried to use it. */ | |
1071 | { | |
1072 | char *p = alloc_anon (NULL, G.pagesize); | |
825b6926 | 1073 | struct page_entry *e; |
1b3e1423 RH |
1074 | if ((size_t)p & (G.pagesize - 1)) |
1075 | { | |
1076 | /* How losing. Discard this one and try another. If we still | |
1077 | can't get something useful, give up. */ | |
1078 | ||
1079 | p = alloc_anon (NULL, G.pagesize); | |
1080 | if ((size_t)p & (G.pagesize - 1)) | |
1081 | abort (); | |
1082 | } | |
825b6926 | 1083 | |
dc297297 | 1084 | /* We have a good page, might as well hold onto it... */ |
825b6926 ZW |
1085 | e = (struct page_entry *) xcalloc (1, sizeof (struct page_entry)); |
1086 | e->bytes = G.pagesize; | |
1087 | e->page = p; | |
1088 | e->next = G.free_pages; | |
1089 | G.free_pages = e; | |
1b3e1423 RH |
1090 | } |
1091 | #endif | |
2be510b8 MM |
1092 | |
1093 | /* Initialize the object size table. */ | |
1094 | for (order = 0; order < HOST_BITS_PER_PTR; ++order) | |
1095 | object_size_table[order] = (size_t) 1 << order; | |
1096 | for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order) | |
b1095f9c MM |
1097 | { |
1098 | size_t s = extra_order_size_table[order - HOST_BITS_PER_PTR]; | |
1099 | ||
1100 | /* If S is not a multiple of the MAX_ALIGNMENT, then round it up | |
1101 | so that we're sure of getting aligned memory. */ | |
1102 | s = CEIL (s, MAX_ALIGNMENT) * MAX_ALIGNMENT; | |
1103 | object_size_table[order] = s; | |
1104 | } | |
2be510b8 MM |
1105 | |
1106 | /* Initialize the objects-per-page table. */ | |
1107 | for (order = 0; order < NUM_ORDERS; ++order) | |
1108 | { | |
1109 | objects_per_page_table[order] = G.pagesize / OBJECT_SIZE (order); | |
1110 | if (objects_per_page_table[order] == 0) | |
1111 | objects_per_page_table[order] = 1; | |
1112 | } | |
1113 | ||
1114 | /* Reset the size_lookup array to put appropriately sized objects in | |
1115 | the special orders. All objects bigger than the previous power | |
1116 | of two, but no greater than the special size, should go in the | |
1117 | new order. */ | |
1118 | for (order = HOST_BITS_PER_PTR; order < NUM_ORDERS; ++order) | |
1119 | { | |
1120 | int o; | |
1121 | int i; | |
1122 | ||
1123 | o = size_lookup[OBJECT_SIZE (order)]; | |
1124 | for (i = OBJECT_SIZE (order); size_lookup [i] == o; --i) | |
1125 | size_lookup[i] = order; | |
1126 | } | |
21341cfd AS |
1127 | } |
1128 | ||
cb2ec151 RH |
1129 | /* Increment the `GC context'. Objects allocated in an outer context |
1130 | are never freed, eliminating the need to register their roots. */ | |
21341cfd AS |
1131 | |
1132 | void | |
1133 | ggc_push_context () | |
1134 | { | |
1135 | ++G.context_depth; | |
1136 | ||
1137 | /* Die on wrap. */ | |
1138 | if (G.context_depth == 0) | |
1139 | abort (); | |
1140 | } | |
1141 | ||
4934cc53 MM |
1142 | /* Merge the SAVE_IN_USE_P and IN_USE_P arrays in P so that IN_USE_P |
1143 | reflects reality. Recalculate NUM_FREE_OBJECTS as well. */ | |
1144 | ||
1145 | static void | |
1146 | ggc_recalculate_in_use_p (p) | |
1147 | page_entry *p; | |
1148 | { | |
1149 | unsigned int i; | |
1150 | size_t num_objects; | |
1151 | ||
1152 | /* Because the past-the-end bit in in_use_p is always set, we | |
1153 | pretend there is one additional object. */ | |
1154 | num_objects = OBJECTS_PER_PAGE (p->order) + 1; | |
1155 | ||
1156 | /* Reset the free object count. */ | |
1157 | p->num_free_objects = num_objects; | |
1158 | ||
1159 | /* Combine the IN_USE_P and SAVE_IN_USE_P arrays. */ | |
1160 | for (i = 0; | |
2be510b8 MM |
1161 | i < CEIL (BITMAP_SIZE (num_objects), |
1162 | sizeof (*p->in_use_p)); | |
4934cc53 MM |
1163 | ++i) |
1164 | { | |
1165 | unsigned long j; | |
1166 | ||
1167 | /* Something is in use if it is marked, or if it was in use in a | |
1168 | context further down the context stack. */ | |
1169 | p->in_use_p[i] |= p->save_in_use_p[i]; | |
1170 | ||
1171 | /* Decrement the free object count for every object allocated. */ | |
1172 | for (j = p->in_use_p[i]; j; j >>= 1) | |
1173 | p->num_free_objects -= (j & 1); | |
1174 | } | |
1175 | ||
1176 | if (p->num_free_objects >= num_objects) | |
1177 | abort (); | |
1178 | } | |
1179 | ||
cb2ec151 RH |
1180 | /* Decrement the `GC context'. All objects allocated since the |
1181 | previous ggc_push_context are migrated to the outer context. */ | |
21341cfd AS |
1182 | |
1183 | void | |
1184 | ggc_pop_context () | |
1185 | { | |
1186 | unsigned order, depth; | |
1187 | ||
1188 | depth = --G.context_depth; | |
1189 | ||
1190 | /* Any remaining pages in the popped context are lowered to the new | |
1191 | current context; i.e. objects allocated in the popped context and | |
1192 | left over are imported into the previous context. */ | |
2be510b8 | 1193 | for (order = 2; order < NUM_ORDERS; order++) |
21341cfd | 1194 | { |
21341cfd AS |
1195 | page_entry *p; |
1196 | ||
1197 | for (p = G.pages[order]; p != NULL; p = p->next) | |
1198 | { | |
1199 | if (p->context_depth > depth) | |
4934cc53 | 1200 | p->context_depth = depth; |
21341cfd AS |
1201 | |
1202 | /* If this page is now in the topmost context, and we'd | |
1203 | saved its allocation state, restore it. */ | |
1204 | else if (p->context_depth == depth && p->save_in_use_p) | |
1205 | { | |
4934cc53 | 1206 | ggc_recalculate_in_use_p (p); |
21341cfd AS |
1207 | free (p->save_in_use_p); |
1208 | p->save_in_use_p = 0; | |
21341cfd AS |
1209 | } |
1210 | } | |
1211 | } | |
1212 | } | |
21341cfd | 1213 | \f |
cb2ec151 RH |
1214 | /* Unmark all objects. */ |
1215 | ||
21341cfd AS |
1216 | static inline void |
1217 | clear_marks () | |
1218 | { | |
1219 | unsigned order; | |
1220 | ||
2be510b8 | 1221 | for (order = 2; order < NUM_ORDERS; order++) |
21341cfd AS |
1222 | { |
1223 | size_t num_objects = OBJECTS_PER_PAGE (order); | |
4934cc53 | 1224 | size_t bitmap_size = BITMAP_SIZE (num_objects + 1); |
21341cfd AS |
1225 | page_entry *p; |
1226 | ||
1227 | for (p = G.pages[order]; p != NULL; p = p->next) | |
1228 | { | |
1229 | #ifdef ENABLE_CHECKING | |
1230 | /* The data should be page-aligned. */ | |
1231 | if ((size_t) p->page & (G.pagesize - 1)) | |
1232 | abort (); | |
1233 | #endif | |
1234 | ||
1235 | /* Pages that aren't in the topmost context are not collected; | |
1236 | nevertheless, we need their in-use bit vectors to store GC | |
1237 | marks. So, back them up first. */ | |
4934cc53 | 1238 | if (p->context_depth < G.context_depth) |
21341cfd | 1239 | { |
4934cc53 MM |
1240 | if (! p->save_in_use_p) |
1241 | p->save_in_use_p = xmalloc (bitmap_size); | |
21341cfd | 1242 | memcpy (p->save_in_use_p, p->in_use_p, bitmap_size); |
21341cfd AS |
1243 | } |
1244 | ||
1245 | /* Reset reset the number of free objects and clear the | |
1246 | in-use bits. These will be adjusted by mark_obj. */ | |
1247 | p->num_free_objects = num_objects; | |
1248 | memset (p->in_use_p, 0, bitmap_size); | |
1249 | ||
1250 | /* Make sure the one-past-the-end bit is always set. */ | |
1251 | p->in_use_p[num_objects / HOST_BITS_PER_LONG] | |
1252 | = ((unsigned long) 1 << (num_objects % HOST_BITS_PER_LONG)); | |
1253 | } | |
1254 | } | |
1255 | } | |
1256 | ||
cb2ec151 RH |
1257 | /* Free all empty pages. Partially empty pages need no attention |
1258 | because the `mark' bit doubles as an `unused' bit. */ | |
1259 | ||
21341cfd AS |
1260 | static inline void |
1261 | sweep_pages () | |
1262 | { | |
1263 | unsigned order; | |
1264 | ||
2be510b8 | 1265 | for (order = 2; order < NUM_ORDERS; order++) |
21341cfd AS |
1266 | { |
1267 | /* The last page-entry to consider, regardless of entries | |
1268 | placed at the end of the list. */ | |
1269 | page_entry * const last = G.page_tails[order]; | |
1270 | ||
1271 | size_t num_objects = OBJECTS_PER_PAGE (order); | |
054f5e69 | 1272 | size_t live_objects; |
21341cfd AS |
1273 | page_entry *p, *previous; |
1274 | int done; | |
1275 | ||
1276 | p = G.pages[order]; | |
1277 | if (p == NULL) | |
1278 | continue; | |
1279 | ||
1280 | previous = NULL; | |
1281 | do | |
1282 | { | |
1283 | page_entry *next = p->next; | |
1284 | ||
1285 | /* Loop until all entries have been examined. */ | |
1286 | done = (p == last); | |
1287 | ||
054f5e69 ZW |
1288 | /* Add all live objects on this page to the count of |
1289 | allocated memory. */ | |
1290 | live_objects = num_objects - p->num_free_objects; | |
1291 | ||
2be510b8 | 1292 | G.allocated += OBJECT_SIZE (order) * live_objects; |
054f5e69 | 1293 | |
21341cfd AS |
1294 | /* Only objects on pages in the topmost context should get |
1295 | collected. */ | |
1296 | if (p->context_depth < G.context_depth) | |
1297 | ; | |
1298 | ||
1299 | /* Remove the page if it's empty. */ | |
054f5e69 | 1300 | else if (live_objects == 0) |
21341cfd AS |
1301 | { |
1302 | if (! previous) | |
1303 | G.pages[order] = next; | |
1304 | else | |
1305 | previous->next = next; | |
1306 | ||
1307 | /* Are we removing the last element? */ | |
1308 | if (p == G.page_tails[order]) | |
1309 | G.page_tails[order] = previous; | |
1310 | free_page (p); | |
1311 | p = previous; | |
1312 | } | |
1313 | ||
1314 | /* If the page is full, move it to the end. */ | |
1315 | else if (p->num_free_objects == 0) | |
1316 | { | |
1317 | /* Don't move it if it's already at the end. */ | |
1318 | if (p != G.page_tails[order]) | |
1319 | { | |
1320 | /* Move p to the end of the list. */ | |
1321 | p->next = NULL; | |
1322 | G.page_tails[order]->next = p; | |
1323 | ||
1324 | /* Update the tail pointer... */ | |
1325 | G.page_tails[order] = p; | |
1326 | ||
1327 | /* ... and the head pointer, if necessary. */ | |
1328 | if (! previous) | |
1329 | G.pages[order] = next; | |
1330 | else | |
1331 | previous->next = next; | |
1332 | p = previous; | |
1333 | } | |
1334 | } | |
1335 | ||
1336 | /* If we've fallen through to here, it's a page in the | |
1337 | topmost context that is neither full nor empty. Such a | |
1338 | page must precede pages at lesser context depth in the | |
1339 | list, so move it to the head. */ | |
1340 | else if (p != G.pages[order]) | |
1341 | { | |
1342 | previous->next = p->next; | |
1343 | p->next = G.pages[order]; | |
1344 | G.pages[order] = p; | |
1345 | /* Are we moving the last element? */ | |
1346 | if (G.page_tails[order] == p) | |
1347 | G.page_tails[order] = previous; | |
1348 | p = previous; | |
1349 | } | |
1350 | ||
1351 | previous = p; | |
1352 | p = next; | |
1353 | } | |
1354 | while (! done); | |
4934cc53 MM |
1355 | |
1356 | /* Now, restore the in_use_p vectors for any pages from contexts | |
1357 | other than the current one. */ | |
1358 | for (p = G.pages[order]; p; p = p->next) | |
1359 | if (p->context_depth != G.context_depth) | |
1360 | ggc_recalculate_in_use_p (p); | |
21341cfd AS |
1361 | } |
1362 | } | |
1363 | ||
1364 | #ifdef GGC_POISON | |
cb2ec151 RH |
1365 | /* Clobber all free objects. */ |
1366 | ||
21341cfd AS |
1367 | static inline void |
1368 | poison_pages () | |
1369 | { | |
1370 | unsigned order; | |
1371 | ||
2be510b8 | 1372 | for (order = 2; order < NUM_ORDERS; order++) |
21341cfd AS |
1373 | { |
1374 | size_t num_objects = OBJECTS_PER_PAGE (order); | |
2be510b8 | 1375 | size_t size = OBJECT_SIZE (order); |
21341cfd AS |
1376 | page_entry *p; |
1377 | ||
1378 | for (p = G.pages[order]; p != NULL; p = p->next) | |
1379 | { | |
1380 | size_t i; | |
c831fdea MM |
1381 | |
1382 | if (p->context_depth != G.context_depth) | |
1383 | /* Since we don't do any collection for pages in pushed | |
1384 | contexts, there's no need to do any poisoning. And | |
1385 | besides, the IN_USE_P array isn't valid until we pop | |
1386 | contexts. */ | |
1387 | continue; | |
1388 | ||
21341cfd AS |
1389 | for (i = 0; i < num_objects; i++) |
1390 | { | |
1391 | size_t word, bit; | |
1392 | word = i / HOST_BITS_PER_LONG; | |
1393 | bit = i % HOST_BITS_PER_LONG; | |
1394 | if (((p->in_use_p[word] >> bit) & 1) == 0) | |
cb2ec151 | 1395 | memset (p->page + i * size, 0xa5, size); |
21341cfd AS |
1396 | } |
1397 | } | |
1398 | } | |
1399 | } | |
1400 | #endif | |
1401 | ||
cb2ec151 RH |
1402 | /* Top level mark-and-sweep routine. */ |
1403 | ||
21341cfd AS |
1404 | void |
1405 | ggc_collect () | |
1406 | { | |
21341cfd AS |
1407 | /* Avoid frequent unnecessary work by skipping collection if the |
1408 | total allocations haven't expanded much since the last | |
1409 | collection. */ | |
1410 | #ifndef GGC_ALWAYS_COLLECT | |
1411 | if (G.allocated < GGC_MIN_EXPAND_FOR_GC * G.allocated_last_gc) | |
1412 | return; | |
1413 | #endif | |
1414 | ||
2a9a326b | 1415 | timevar_push (TV_GC); |
21341cfd | 1416 | if (!quiet_flag) |
b9bfacf0 | 1417 | fprintf (stderr, " {GC %luk -> ", (unsigned long) G.allocated / 1024); |
21341cfd | 1418 | |
054f5e69 ZW |
1419 | /* Zero the total allocated bytes. This will be recalculated in the |
1420 | sweep phase. */ | |
21341cfd AS |
1421 | G.allocated = 0; |
1422 | ||
1423 | /* Release the pages we freed the last time we collected, but didn't | |
1424 | reuse in the interim. */ | |
1425 | release_pages (); | |
1426 | ||
1427 | clear_marks (); | |
1428 | ggc_mark_roots (); | |
21341cfd AS |
1429 | |
1430 | #ifdef GGC_POISON | |
1431 | poison_pages (); | |
1432 | #endif | |
1433 | ||
cb2ec151 RH |
1434 | sweep_pages (); |
1435 | ||
21341cfd | 1436 | G.allocated_last_gc = G.allocated; |
a70261ee RH |
1437 | if (G.allocated_last_gc < GGC_MIN_LAST_ALLOCATED) |
1438 | G.allocated_last_gc = GGC_MIN_LAST_ALLOCATED; | |
21341cfd | 1439 | |
2a9a326b | 1440 | timevar_pop (TV_GC); |
21341cfd | 1441 | |
21341cfd | 1442 | if (!quiet_flag) |
2a9a326b | 1443 | fprintf (stderr, "%luk}", (unsigned long) G.allocated / 1024); |
21341cfd | 1444 | } |
3277221c MM |
1445 | |
1446 | /* Print allocation statistics. */ | |
fba0bfd4 ZW |
1447 | #define SCALE(x) ((unsigned long) ((x) < 1024*10 \ |
1448 | ? (x) \ | |
1449 | : ((x) < 1024*1024*10 \ | |
1450 | ? (x) / 1024 \ | |
1451 | : (x) / (1024*1024)))) | |
1452 | #define LABEL(x) ((x) < 1024*10 ? ' ' : ((x) < 1024*1024*10 ? 'k' : 'M')) | |
3277221c MM |
1453 | |
1454 | void | |
fba0bfd4 | 1455 | ggc_print_statistics () |
3277221c MM |
1456 | { |
1457 | struct ggc_statistics stats; | |
4934cc53 | 1458 | unsigned int i; |
fba0bfd4 | 1459 | size_t total_overhead = 0; |
3277221c MM |
1460 | |
1461 | /* Clear the statistics. */ | |
d219c7f1 | 1462 | memset (&stats, 0, sizeof (stats)); |
3277221c MM |
1463 | |
1464 | /* Make sure collection will really occur. */ | |
1465 | G.allocated_last_gc = 0; | |
1466 | ||
1467 | /* Collect and print the statistics common across collectors. */ | |
fba0bfd4 | 1468 | ggc_print_common_statistics (stderr, &stats); |
3277221c | 1469 | |
4934cc53 MM |
1470 | /* Release free pages so that we will not count the bytes allocated |
1471 | there as part of the total allocated memory. */ | |
1472 | release_pages (); | |
1473 | ||
3277221c MM |
1474 | /* Collect some information about the various sizes of |
1475 | allocation. */ | |
fba0bfd4 | 1476 | fprintf (stderr, "\n%-5s %10s %10s %10s\n", |
9fd51e67 | 1477 | "Size", "Allocated", "Used", "Overhead"); |
2be510b8 | 1478 | for (i = 0; i < NUM_ORDERS; ++i) |
3277221c MM |
1479 | { |
1480 | page_entry *p; | |
1481 | size_t allocated; | |
1482 | size_t in_use; | |
fba0bfd4 | 1483 | size_t overhead; |
3277221c MM |
1484 | |
1485 | /* Skip empty entries. */ | |
1486 | if (!G.pages[i]) | |
1487 | continue; | |
1488 | ||
fba0bfd4 | 1489 | overhead = allocated = in_use = 0; |
3277221c MM |
1490 | |
1491 | /* Figure out the total number of bytes allocated for objects of | |
fba0bfd4 ZW |
1492 | this size, and how many of them are actually in use. Also figure |
1493 | out how much memory the page table is using. */ | |
3277221c MM |
1494 | for (p = G.pages[i]; p; p = p->next) |
1495 | { | |
1496 | allocated += p->bytes; | |
1497 | in_use += | |
2be510b8 | 1498 | (OBJECTS_PER_PAGE (i) - p->num_free_objects) * OBJECT_SIZE (i); |
fba0bfd4 ZW |
1499 | |
1500 | overhead += (sizeof (page_entry) - sizeof (long) | |
1501 | + BITMAP_SIZE (OBJECTS_PER_PAGE (i) + 1)); | |
3277221c | 1502 | } |
9fd51e67 | 1503 | fprintf (stderr, "%-5d %10ld%c %10ld%c %10ld%c\n", OBJECT_SIZE (i), |
fba0bfd4 ZW |
1504 | SCALE (allocated), LABEL (allocated), |
1505 | SCALE (in_use), LABEL (in_use), | |
1506 | SCALE (overhead), LABEL (overhead)); | |
1507 | total_overhead += overhead; | |
3277221c | 1508 | } |
fba0bfd4 ZW |
1509 | fprintf (stderr, "%-5s %10ld%c %10ld%c %10ld%c\n", "Total", |
1510 | SCALE (G.bytes_mapped), LABEL (G.bytes_mapped), | |
1511 | SCALE (G.allocated), LABEL(G.allocated), | |
1512 | SCALE (total_overhead), LABEL (total_overhead)); | |
3277221c | 1513 | } |