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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [boehm-gc/] [blacklst.c] - Blame information for rev 721

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1 721 jeremybenn
/*
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 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
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 *
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 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
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 *
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 * Permission is hereby granted to use or copy this program
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 * for any purpose,  provided the above notices are retained on all copies.
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 * Permission to modify the code and to distribute modified code is granted,
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 * provided the above notices are retained, and a notice that the code was
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 * modified is included with the above copyright notice.
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 */
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/* Boehm, August 9, 1995 6:09 pm PDT */
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# include "private/gc_priv.h"
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17
/*
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 * We maintain several hash tables of hblks that have had false hits.
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 * Each contains one bit per hash bucket;  If any page in the bucket
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 * has had a false hit, we assume that all of them have.
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 * See the definition of page_hash_table in gc_private.h.
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 * False hits from the stack(s) are much more dangerous than false hits
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 * from elsewhere, since the former can pin a large object that spans the
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 * block, eventhough it does not start on the dangerous block.
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 */
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27
/*
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 * Externally callable routines are:
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30
 * GC_add_to_black_list_normal
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 * GC_add_to_black_list_stack
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 * GC_promote_black_lists
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 * GC_is_black_listed
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 *
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 * All require that the allocator lock is held.
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 */
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/* Pointers to individual tables.  We replace one table by another by   */
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/* switching these pointers.                                            */
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word * GC_old_normal_bl;
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                /* Nonstack false references seen at last full          */
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                /* collection.                                          */
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word * GC_incomplete_normal_bl;
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                /* Nonstack false references seen since last            */
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                /* full collection.                                     */
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word * GC_old_stack_bl;
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word * GC_incomplete_stack_bl;
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49
word GC_total_stack_black_listed;
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51
word GC_black_list_spacing = MINHINCR*HBLKSIZE;  /* Initial rough guess */
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53
void GC_clear_bl();
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55
# if defined(__STDC__) || defined(__cplusplus)
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    void GC_default_print_heap_obj_proc(ptr_t p)
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# else
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    void GC_default_print_heap_obj_proc(p)
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    ptr_t p;
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# endif
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{
62
    ptr_t base = GC_base(p);
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64
    GC_err_printf2("start: 0x%lx, appr. length: %ld", base, GC_size(base));
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}
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void (*GC_print_heap_obj) GC_PROTO((ptr_t p)) =
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                                GC_default_print_heap_obj_proc;
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void GC_print_source_ptr(p)
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ptr_t p;
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{
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    ptr_t base = GC_base(p);
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    if (0 == base) {
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        if (0 == p) {
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            GC_err_printf0("in register");
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        } else {
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            GC_err_printf0("in root set");
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        }
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    } else {
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        GC_err_printf0("in object at ");
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        (*GC_print_heap_obj)(base);
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    }
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}
85
 
86
void GC_bl_init()
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{
88
    if (!GC_all_interior_pointers) {
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      GC_old_normal_bl = (word *)
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                         GC_scratch_alloc((word)(sizeof (page_hash_table)));
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      GC_incomplete_normal_bl = (word *)GC_scratch_alloc
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                                        ((word)(sizeof(page_hash_table)));
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      if (GC_old_normal_bl == 0 || GC_incomplete_normal_bl == 0) {
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        GC_err_printf0("Insufficient memory for black list\n");
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        EXIT();
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      }
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      GC_clear_bl(GC_old_normal_bl);
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      GC_clear_bl(GC_incomplete_normal_bl);
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    }
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    GC_old_stack_bl = (word *)GC_scratch_alloc((word)(sizeof(page_hash_table)));
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    GC_incomplete_stack_bl = (word *)GC_scratch_alloc
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                                        ((word)(sizeof(page_hash_table)));
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    if (GC_old_stack_bl == 0 || GC_incomplete_stack_bl == 0) {
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        GC_err_printf0("Insufficient memory for black list\n");
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        EXIT();
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    }
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    GC_clear_bl(GC_old_stack_bl);
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    GC_clear_bl(GC_incomplete_stack_bl);
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}
110
 
111
void GC_clear_bl(doomed)
112
word *doomed;
113
{
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    BZERO(doomed, sizeof(page_hash_table));
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}
116
 
117
void GC_copy_bl(old, new)
118
word *new, *old;
119
{
120
    BCOPY(old, new, sizeof(page_hash_table));
121
}
122
 
123
static word total_stack_black_listed();
124
 
125
/* Signal the completion of a collection.  Turn the incomplete black    */
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/* lists into new black lists, etc.                                     */
127
void GC_promote_black_lists()
128
{
129
    word * very_old_normal_bl = GC_old_normal_bl;
130
    word * very_old_stack_bl = GC_old_stack_bl;
131
 
132
    GC_old_normal_bl = GC_incomplete_normal_bl;
133
    GC_old_stack_bl = GC_incomplete_stack_bl;
134
    if (!GC_all_interior_pointers) {
135
      GC_clear_bl(very_old_normal_bl);
136
    }
137
    GC_clear_bl(very_old_stack_bl);
138
    GC_incomplete_normal_bl = very_old_normal_bl;
139
    GC_incomplete_stack_bl = very_old_stack_bl;
140
    GC_total_stack_black_listed = total_stack_black_listed();
141
#   ifdef PRINTSTATS
142
        GC_printf1("%ld bytes in heap blacklisted for interior pointers\n",
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                   (unsigned long)GC_total_stack_black_listed);
144
#   endif
145
    if (GC_total_stack_black_listed != 0) {
146
        GC_black_list_spacing =
147
                HBLKSIZE*(GC_heapsize/GC_total_stack_black_listed);
148
    }
149
    if (GC_black_list_spacing < 3 * HBLKSIZE) {
150
        GC_black_list_spacing = 3 * HBLKSIZE;
151
    }
152
    if (GC_black_list_spacing > MAXHINCR * HBLKSIZE) {
153
        GC_black_list_spacing = MAXHINCR * HBLKSIZE;
154
        /* Makes it easier to allocate really huge blocks, which otherwise */
155
        /* may have problems with nonuniform blacklist distributions.      */
156
        /* This way we should always succeed immediately after growing the */
157
        /* heap.                                                           */
158
    }
159
}
160
 
161
void GC_unpromote_black_lists()
162
{
163
    if (!GC_all_interior_pointers) {
164
      GC_copy_bl(GC_old_normal_bl, GC_incomplete_normal_bl);
165
    }
166
    GC_copy_bl(GC_old_stack_bl, GC_incomplete_stack_bl);
167
}
168
 
169
/* P is not a valid pointer reference, but it falls inside      */
170
/* the plausible heap bounds.                                   */
171
/* Add it to the normal incomplete black list if appropriate.   */
172
#ifdef PRINT_BLACK_LIST
173
  void GC_add_to_black_list_normal(p, source)
174
  ptr_t source;
175
#else
176
  void GC_add_to_black_list_normal(p)
177
#endif
178
word p;
179
{
180
    if (!(GC_modws_valid_offsets[p & (sizeof(word)-1)])) return;
181
    {
182
        register int index = PHT_HASH(p);
183
 
184
        if (HDR(p) == 0 || get_pht_entry_from_index(GC_old_normal_bl, index)) {
185
#           ifdef PRINT_BLACK_LIST
186
                if (!get_pht_entry_from_index(GC_incomplete_normal_bl, index)) {
187
                  GC_err_printf2(
188
                        "Black listing (normal) 0x%lx referenced from 0x%lx ",
189
                        (unsigned long) p, (unsigned long) source);
190
                  GC_print_source_ptr(source);
191
                  GC_err_puts("\n");
192
                }
193
#           endif
194
            set_pht_entry_from_index(GC_incomplete_normal_bl, index);
195
        } /* else this is probably just an interior pointer to an allocated */
196
          /* object, and isn't worth black listing.                         */
197
    }
198
}
199
 
200
/* And the same for false pointers from the stack. */
201
#ifdef PRINT_BLACK_LIST
202
  void GC_add_to_black_list_stack(p, source)
203
  ptr_t source;
204
#else
205
  void GC_add_to_black_list_stack(p)
206
#endif
207
word p;
208
{
209
    register int index = PHT_HASH(p);
210
 
211
    if (HDR(p) == 0 || get_pht_entry_from_index(GC_old_stack_bl, index)) {
212
#       ifdef PRINT_BLACK_LIST
213
            if (!get_pht_entry_from_index(GC_incomplete_stack_bl, index)) {
214
                  GC_err_printf2(
215
                        "Black listing (stack) 0x%lx referenced from 0x%lx ",
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                        (unsigned long)p, (unsigned long)source);
217
                  GC_print_source_ptr(source);
218
                  GC_err_puts("\n");
219
            }
220
#       endif
221
        set_pht_entry_from_index(GC_incomplete_stack_bl, index);
222
    }
223
}
224
 
225
/*
226
 * Is the block starting at h of size len bytes black listed?   If so,
227
 * return the address of the next plausible r such that (r, len) might not
228
 * be black listed.  (R may not actually be in the heap.  We guarantee only
229
 * that every smaller value of r after h is also black listed.)
230
 * If (h,len) is not black listed, return 0.
231
 * Knows about the structure of the black list hash tables.
232
 */
233
struct hblk * GC_is_black_listed(h, len)
234
struct hblk * h;
235
word len;
236
{
237
    register int index = PHT_HASH((word)h);
238
    register word i;
239
    word nblocks = divHBLKSZ(len);
240
 
241
    if (!GC_all_interior_pointers) {
242
      if (get_pht_entry_from_index(GC_old_normal_bl, index)
243
          || get_pht_entry_from_index(GC_incomplete_normal_bl, index)) {
244
        return(h+1);
245
      }
246
    }
247
 
248
    for (i = 0; ; ) {
249
        if (GC_old_stack_bl[divWORDSZ(index)] == 0
250
            && GC_incomplete_stack_bl[divWORDSZ(index)] == 0) {
251
            /* An easy case */
252
            i += WORDSZ - modWORDSZ(index);
253
        } else {
254
          if (get_pht_entry_from_index(GC_old_stack_bl, index)
255
              || get_pht_entry_from_index(GC_incomplete_stack_bl, index)) {
256
            return(h+i+1);
257
          }
258
          i++;
259
        }
260
        if (i >= nblocks) break;
261
        index = PHT_HASH((word)(h+i));
262
    }
263
    return(0);
264
}
265
 
266
 
267
/* Return the number of blacklisted blocks in a given range.    */
268
/* Used only for statistical purposes.                          */
269
/* Looks only at the GC_incomplete_stack_bl.                    */
270
word GC_number_stack_black_listed(start, endp1)
271
struct hblk *start, *endp1;
272
{
273
    register struct hblk * h;
274
    word result = 0;
275
 
276
    for (h = start; h < endp1; h++) {
277
        register int index = PHT_HASH((word)h);
278
 
279
        if (get_pht_entry_from_index(GC_old_stack_bl, index)) result++;
280
    }
281
    return(result);
282
}
283
 
284
 
285
/* Return the total number of (stack) black-listed bytes. */
286
static word total_stack_black_listed()
287
{
288
    register unsigned i;
289
    word total = 0;
290
 
291
    for (i = 0; i < GC_n_heap_sects; i++) {
292
        struct hblk * start = (struct hblk *) GC_heap_sects[i].hs_start;
293
        word len = (word) GC_heap_sects[i].hs_bytes;
294
        struct hblk * endp1 = start + len/HBLKSIZE;
295
 
296
        total += GC_number_stack_black_listed(start, endp1);
297
    }
298
    return(total * HBLKSIZE);
299
}
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