Line data Source code
1 : /*
2 : * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 : * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
4 : * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
5 : *
6 : * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
7 : * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
8 : *
9 : * Permission is hereby granted to use or copy this program
10 : * for any purpose, provided the above notices are retained on all copies.
11 : * Permission to modify the code and to distribute modified code is granted,
12 : * provided the above notices are retained, and a notice that the code was
13 : * modified is included with the above copyright notice.
14 : */
15 :
16 : #include "private/gc_priv.h"
17 :
18 : /*
19 : * This implements:
20 : * 1. allocation of heap block headers
21 : * 2. A map from addresses to heap block addresses to heap block headers
22 : *
23 : * Access speed is crucial. We implement an index structure based on a 2
24 : * level tree.
25 : */
26 :
27 : STATIC bottom_index * GC_all_bottom_indices = 0;
28 : /* Pointer to first (lowest addr) */
29 : /* bottom_index. */
30 :
31 : STATIC bottom_index * GC_all_bottom_indices_end = 0;
32 : /* Pointer to last (highest addr) */
33 : /* bottom_index. */
34 :
35 : /* Non-macro version of header location routine */
36 1372854 : GC_INNER hdr * GC_find_header(ptr_t h)
37 : {
38 : # ifdef HASH_TL
39 : hdr * result;
40 1372854 : GET_HDR(h, result);
41 1372854 : return(result);
42 : # else
43 : return(HDR_INNER(h));
44 : # endif
45 : }
46 :
47 : /* Handle a header cache miss. Returns a pointer to the */
48 : /* header corresponding to p, if p can possibly be a valid */
49 : /* object pointer, and 0 otherwise. */
50 : /* GUARANTEED to return 0 for a pointer past the first page */
51 : /* of an object unless both GC_all_interior_pointers is set */
52 : /* and p is in fact a valid object pointer. */
53 : /* Never returns a pointer to a free hblk. */
54 : GC_INNER hdr *
55 : #ifdef PRINT_BLACK_LIST
56 : GC_header_cache_miss(ptr_t p, hdr_cache_entry *hce, ptr_t source)
57 : #else
58 1335041 : GC_header_cache_miss(ptr_t p, hdr_cache_entry *hce)
59 : #endif
60 : {
61 : hdr *hhdr;
62 : HC_MISS();
63 1335041 : GET_HDR(p, hhdr);
64 1335041 : if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
65 925491 : if (GC_all_interior_pointers) {
66 0 : if (hhdr != 0) {
67 0 : ptr_t current = p;
68 :
69 0 : current = (ptr_t)HBLKPTR(current);
70 : do {
71 0 : current = current - HBLKSIZE*(word)hhdr;
72 0 : hhdr = HDR(current);
73 0 : } while(IS_FORWARDING_ADDR_OR_NIL(hhdr));
74 : /* current points to near the start of the large object */
75 0 : if (hhdr -> hb_flags & IGNORE_OFF_PAGE)
76 0 : return 0;
77 0 : if (HBLK_IS_FREE(hhdr)
78 0 : || p - current >= (ptrdiff_t)(hhdr->hb_sz)) {
79 0 : GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
80 : /* Pointer past the end of the block */
81 0 : return 0;
82 : }
83 : } else {
84 0 : GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
85 : /* And return zero: */
86 : }
87 : GC_ASSERT(hhdr == 0 || !HBLK_IS_FREE(hhdr));
88 0 : return hhdr;
89 : /* Pointers past the first page are probably too rare */
90 : /* to add them to the cache. We don't. */
91 : /* And correctness relies on the fact that we don't. */
92 : } else {
93 925491 : if (hhdr == 0) {
94 925486 : GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
95 : }
96 925491 : return 0;
97 : }
98 : } else {
99 409550 : if (HBLK_IS_FREE(hhdr)) {
100 770 : GC_ADD_TO_BLACK_LIST_NORMAL(p, source);
101 770 : return 0;
102 : } else {
103 408780 : hce -> block_addr = (word)(p) >> LOG_HBLKSIZE;
104 408780 : hce -> hce_hdr = hhdr;
105 408780 : return hhdr;
106 : }
107 : }
108 : }
109 :
110 : /* Routines to dynamically allocate collector data structures that will */
111 : /* never be freed. */
112 :
113 : static ptr_t scratch_free_ptr = 0;
114 :
115 : /* GC_scratch_last_end_ptr is end point of last obtained scratch area. */
116 : /* GC_scratch_end_ptr is end point of current scratch area. */
117 :
118 43662 : GC_INNER ptr_t GC_scratch_alloc(size_t bytes)
119 : {
120 43662 : register ptr_t result = scratch_free_ptr;
121 :
122 43662 : bytes += GRANULE_BYTES-1;
123 43662 : bytes &= ~(GRANULE_BYTES-1);
124 43662 : scratch_free_ptr += bytes;
125 43662 : if (scratch_free_ptr <= GC_scratch_end_ptr) {
126 42823 : return(result);
127 : }
128 : {
129 839 : word bytes_to_get = MINHINCR * HBLKSIZE;
130 :
131 839 : if (bytes_to_get <= bytes) {
132 : /* Undo the damage, and get memory directly */
133 169 : bytes_to_get = bytes;
134 : # ifdef USE_MMAP
135 : bytes_to_get += GC_page_size - 1;
136 : bytes_to_get &= ~(GC_page_size - 1);
137 : # endif
138 169 : result = (ptr_t)GET_MEM(bytes_to_get);
139 : GC_add_to_our_memory(result, bytes_to_get);
140 169 : scratch_free_ptr -= bytes;
141 169 : GC_scratch_last_end_ptr = result + bytes;
142 169 : return(result);
143 : }
144 670 : result = (ptr_t)GET_MEM(bytes_to_get);
145 : GC_add_to_our_memory(result, bytes_to_get);
146 670 : if (result == 0) {
147 0 : if (GC_print_stats)
148 0 : GC_log_printf("Out of memory - trying to allocate less\n");
149 0 : scratch_free_ptr -= bytes;
150 0 : bytes_to_get = bytes;
151 : # ifdef USE_MMAP
152 : bytes_to_get += GC_page_size - 1;
153 : bytes_to_get &= ~(GC_page_size - 1);
154 : # endif
155 0 : result = (ptr_t)GET_MEM(bytes_to_get);
156 : GC_add_to_our_memory(result, bytes_to_get);
157 0 : return result;
158 : }
159 670 : scratch_free_ptr = result;
160 670 : GC_scratch_end_ptr = scratch_free_ptr + bytes_to_get;
161 670 : GC_scratch_last_end_ptr = GC_scratch_end_ptr;
162 670 : return(GC_scratch_alloc(bytes));
163 : }
164 : }
165 :
166 : static hdr * hdr_free_list = 0;
167 :
168 : /* Return an uninitialized header */
169 49177 : static hdr * alloc_hdr(void)
170 : {
171 : register hdr * result;
172 :
173 49177 : if (hdr_free_list == 0) {
174 37220 : result = (hdr *) GC_scratch_alloc((word)(sizeof(hdr)));
175 : } else {
176 11957 : result = hdr_free_list;
177 11957 : hdr_free_list = (hdr *) (result -> hb_next);
178 : }
179 49177 : return(result);
180 : }
181 :
182 27529 : GC_INLINE void free_hdr(hdr * hhdr)
183 : {
184 27529 : hhdr -> hb_next = (struct hblk *) hdr_free_list;
185 27529 : hdr_free_list = hhdr;
186 27529 : }
187 :
188 : #ifdef COUNT_HDR_CACHE_HITS
189 : /* Used for debugging/profiling (the symbols are externally visible). */
190 : word GC_hdr_cache_hits = 0;
191 : word GC_hdr_cache_misses = 0;
192 : #endif
193 :
194 163 : GC_INNER void GC_init_headers(void)
195 : {
196 : register unsigned i;
197 :
198 163 : GC_all_nils = (bottom_index *)GC_scratch_alloc((word)sizeof(bottom_index));
199 163 : if (GC_all_nils == NULL) {
200 0 : GC_err_printf("Insufficient memory for GC_all_nils\n");
201 0 : EXIT();
202 : }
203 163 : BZERO(GC_all_nils, sizeof(bottom_index));
204 333987 : for (i = 0; i < TOP_SZ; i++) {
205 333824 : GC_top_index[i] = GC_all_nils;
206 : }
207 163 : }
208 :
209 : /* Make sure that there is a bottom level index block for address addr */
210 : /* Return FALSE on failure. */
211 153375 : static GC_bool get_index(word addr)
212 : {
213 153375 : word hi = (word)(addr) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
214 : bottom_index * r;
215 : bottom_index * p;
216 : bottom_index ** prev;
217 : bottom_index *pi;
218 :
219 : # ifdef HASH_TL
220 153375 : word i = TL_HASH(hi);
221 : bottom_index * old;
222 :
223 153375 : old = p = GC_top_index[i];
224 306750 : while(p != GC_all_nils) {
225 153151 : if (p -> key == hi) return(TRUE);
226 0 : p = p -> hash_link;
227 : }
228 224 : r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
229 224 : if (r == 0) return(FALSE);
230 224 : BZERO(r, sizeof (bottom_index));
231 224 : r -> hash_link = old;
232 224 : GC_top_index[i] = r;
233 : # else
234 : if (GC_top_index[hi] != GC_all_nils) return(TRUE);
235 : r = (bottom_index*)GC_scratch_alloc((word)(sizeof (bottom_index)));
236 : if (r == 0) return(FALSE);
237 : GC_top_index[hi] = r;
238 : BZERO(r, sizeof (bottom_index));
239 : # endif
240 224 : r -> key = hi;
241 : /* Add it to the list of bottom indices */
242 224 : prev = &GC_all_bottom_indices; /* pointer to p */
243 224 : pi = 0; /* bottom_index preceding p */
244 825 : while ((p = *prev) != 0 && p -> key < hi) {
245 377 : pi = p;
246 377 : prev = &(p -> asc_link);
247 : }
248 224 : r -> desc_link = pi;
249 224 : if (0 == p) {
250 209 : GC_all_bottom_indices_end = r;
251 : } else {
252 15 : p -> desc_link = r;
253 : }
254 224 : r -> asc_link = p;
255 224 : *prev = r;
256 224 : return(TRUE);
257 : }
258 :
259 : /* Install a header for block h. */
260 : /* The header is uninitialized. */
261 : /* Returns the header or 0 on failure. */
262 49177 : GC_INNER struct hblkhdr * GC_install_header(struct hblk *h)
263 : {
264 : hdr * result;
265 :
266 49177 : if (!get_index((word) h)) return(0);
267 49177 : result = alloc_hdr();
268 49177 : if (result) {
269 49177 : SET_HDR(h, result);
270 : # ifdef USE_MUNMAP
271 : result -> hb_last_reclaimed = (unsigned short)GC_gc_no;
272 : # endif
273 : }
274 49177 : return(result);
275 : }
276 :
277 : /* Set up forwarding counts for block h of size sz */
278 52091 : GC_INNER GC_bool GC_install_counts(struct hblk *h, size_t sz/* bytes */)
279 : {
280 : struct hblk * hbp;
281 : word i;
282 :
283 104198 : for (hbp = h; (char *)hbp < (char *)h + sz; hbp += BOTTOM_SZ) {
284 52107 : if (!get_index((word) hbp)) return(FALSE);
285 : }
286 52091 : if (!get_index((word)h + sz - 1)) return(FALSE);
287 77394 : for (hbp = h + 1; (char *)hbp < (char *)h + sz; hbp += 1) {
288 25303 : i = HBLK_PTR_DIFF(hbp, h);
289 25303 : SET_HDR(hbp, (hdr *)(i > MAX_JUMP? MAX_JUMP : i));
290 : }
291 52091 : return(TRUE);
292 : }
293 :
294 : /* Remove the header for block h */
295 27529 : GC_INNER void GC_remove_header(struct hblk *h)
296 : {
297 : hdr **ha;
298 27529 : GET_HDR_ADDR(h, ha);
299 27529 : free_hdr(*ha);
300 27529 : *ha = 0;
301 27529 : }
302 :
303 : /* Remove forwarding counts for h */
304 31050 : GC_INNER void GC_remove_counts(struct hblk *h, size_t sz/* bytes */)
305 : {
306 : register struct hblk * hbp;
307 159134 : for (hbp = h+1; (char *)hbp < (char *)h + sz; hbp += 1) {
308 128084 : SET_HDR(hbp, 0);
309 : }
310 31050 : }
311 :
312 : /* Apply fn to all allocated blocks */
313 : /*VARARGS1*/
314 504 : void GC_apply_to_all_blocks(void (*fn)(struct hblk *h, word client_data),
315 : word client_data)
316 : {
317 : signed_word j;
318 : bottom_index * index_p;
319 :
320 1836 : for (index_p = GC_all_bottom_indices; index_p != 0;
321 828 : index_p = index_p -> asc_link) {
322 763948 : for (j = BOTTOM_SZ-1; j >= 0;) {
323 762292 : if (!IS_FORWARDING_ADDR_OR_NIL(index_p->index[j])) {
324 154564 : if (!HBLK_IS_FREE(index_p->index[j])) {
325 152798 : (*fn)(((struct hblk *)
326 152798 : (((index_p->key << LOG_BOTTOM_SZ) + (word)j)
327 : << LOG_HBLKSIZE)),
328 : client_data);
329 : }
330 154564 : j--;
331 607728 : } else if (index_p->index[j] == 0) {
332 604862 : j--;
333 : } else {
334 2866 : j -= (signed_word)(index_p->index[j]);
335 : }
336 : }
337 : }
338 504 : }
339 :
340 : /* Get the next valid block whose address is at least h */
341 : /* Return 0 if there is none. */
342 1115 : GC_INNER struct hblk * GC_next_used_block(struct hblk *h)
343 : {
344 : register bottom_index * bi;
345 1115 : register word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
346 :
347 1115 : GET_BI(h, bi);
348 1115 : if (bi == GC_all_nils) {
349 258 : register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
350 258 : bi = GC_all_bottom_indices;
351 258 : while (bi != 0 && bi -> key < hi) bi = bi -> asc_link;
352 258 : j = 0;
353 : }
354 2545 : while(bi != 0) {
355 297644 : while (j < BOTTOM_SZ) {
356 296157 : hdr * hhdr = bi -> index[j];
357 296157 : if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
358 294406 : j++;
359 : } else {
360 1751 : if (!HBLK_IS_FREE(hhdr)) {
361 857 : return((struct hblk *)
362 857 : (((bi -> key << LOG_BOTTOM_SZ) + j)
363 : << LOG_HBLKSIZE));
364 : } else {
365 894 : j += divHBLKSZ(hhdr -> hb_sz);
366 : }
367 : }
368 : }
369 315 : j = 0;
370 315 : bi = bi -> asc_link;
371 : }
372 258 : return(0);
373 : }
374 :
375 : /* Get the last (highest address) block whose address is */
376 : /* at most h. Return 0 if there is none. */
377 : /* Unlike the above, this may return a free block. */
378 424 : GC_INNER struct hblk * GC_prev_block(struct hblk *h)
379 : {
380 : register bottom_index * bi;
381 424 : register signed_word j = ((word)h >> LOG_HBLKSIZE) & (BOTTOM_SZ-1);
382 :
383 424 : GET_BI(h, bi);
384 424 : if (bi == GC_all_nils) {
385 0 : register word hi = (word)h >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE);
386 0 : bi = GC_all_bottom_indices_end;
387 0 : while (bi != 0 && bi -> key > hi) bi = bi -> desc_link;
388 0 : j = BOTTOM_SZ - 1;
389 : }
390 1034 : while(bi != 0) {
391 118698 : while (j >= 0) {
392 118067 : hdr * hhdr = bi -> index[j];
393 118067 : if (0 == hhdr) {
394 117807 : --j;
395 260 : } else if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
396 1 : j -= (signed_word)hhdr;
397 : } else {
398 259 : return((struct hblk *)
399 259 : (((bi -> key << LOG_BOTTOM_SZ) + j)
400 : << LOG_HBLKSIZE));
401 : }
402 : }
403 186 : j = BOTTOM_SZ - 1;
404 186 : bi = bi -> desc_link;
405 : }
406 165 : return(0);
407 : }
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