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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [boehm-gc/] [include/] [private/] [gc_pmark.h] - Blame information for rev 721

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1 721 jeremybenn
/*
2
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
3
 * Copyright (c) 2001 by Hewlett-Packard Company. All rights reserved.
4
 *
5
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
6
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
7
 *
8
 * Permission is hereby granted to use or copy this program
9
 * for any purpose,  provided the above notices are retained on all copies.
10
 * Permission to modify the code and to distribute modified code is granted,
11
 * provided the above notices are retained, and a notice that the code was
12
 * modified is included with the above copyright notice.
13
 *
14
 */
15
 
16
/* Private declarations of GC marker data structures and macros */
17
 
18
/*
19
 * Declarations of mark stack.  Needed by marker and client supplied mark
20
 * routines.  Transitively include gc_priv.h.
21
 * (Note that gc_priv.h should not be included before this, since this
22
 * includes dbg_mlc.h, which wants to include gc_priv.h AFTER defining
23
 * I_HIDE_POINTERS.)
24
 */
25
#ifndef GC_PMARK_H
26
# define GC_PMARK_H
27
 
28
# include "gc.h"        /* For configuration */
29
 
30
# if defined(KEEP_BACK_PTRS) || defined(PRINT_BLACK_LIST)
31
#   include "dbg_mlc.h"
32
# endif
33
# ifndef GC_MARK_H
34
#   include "../gc_mark.h"
35
# endif
36
# ifndef GC_PRIVATE_H
37
#   include "gc_priv.h"
38
# endif
39
 
40
/* The real declarations of the following is in gc_priv.h, so that      */
41
/* we can avoid scanning the following table.                           */
42
/*
43
extern mark_proc GC_mark_procs[MAX_MARK_PROCS];
44
*/
45
 
46
/*
47
 * Mark descriptor stuff that should remain private for now, mostly
48
 * because it's hard to export WORDSZ without including gcconfig.h.
49
 */
50
# define BITMAP_BITS (WORDSZ - GC_DS_TAG_BITS)
51
# define PROC(descr) \
52
        (GC_mark_procs[((descr) >> GC_DS_TAG_BITS) & (GC_MAX_MARK_PROCS-1)])
53
# define ENV(descr) \
54
        ((descr) >> (GC_DS_TAG_BITS + GC_LOG_MAX_MARK_PROCS))
55
# define MAX_ENV \
56
        (((word)1 << (WORDSZ - GC_DS_TAG_BITS - GC_LOG_MAX_MARK_PROCS)) - 1)
57
 
58
 
59
extern word GC_n_mark_procs;
60
 
61
/* Number of mark stack entries to discard on overflow. */
62
#define GC_MARK_STACK_DISCARDS (INITIAL_MARK_STACK_SIZE/8)
63
 
64
typedef struct GC_ms_entry {
65
    GC_word * mse_start;   /* First word of object */
66
    GC_word mse_descr;  /* Descriptor; low order two bits are tags,     */
67
                        /* identifying the upper 30 bits as one of the  */
68
                        /* following:                                   */
69
} mse;
70
 
71
extern word GC_mark_stack_size;
72
 
73
extern mse * GC_mark_stack_limit;
74
 
75
#ifdef PARALLEL_MARK
76
  extern mse * VOLATILE GC_mark_stack_top;
77
#else
78
  extern mse * GC_mark_stack_top;
79
#endif
80
 
81
extern mse * GC_mark_stack;
82
 
83
#ifdef PARALLEL_MARK
84
    /*
85
     * Allow multiple threads to participate in the marking process.
86
     * This works roughly as follows:
87
     *  The main mark stack never shrinks, but it can grow.
88
     *
89
     *  The initiating threads holds the GC lock, and sets GC_help_wanted.
90
     *
91
     *  Other threads:
92
     *     1) update helper_count (while holding mark_lock.)
93
     *     2) allocate a local mark stack
94
     *     repeatedly:
95
     *          3) Steal a global mark stack entry by atomically replacing
96
     *             its descriptor with 0.
97
     *          4) Copy it to the local stack.
98
     *          5) Mark on the local stack until it is empty, or
99
     *             it may be profitable to copy it back.
100
     *          6) If necessary, copy local stack to global one,
101
     *             holding mark lock.
102
     *    7) Stop when the global mark stack is empty.
103
     *    8) decrement helper_count (holding mark_lock).
104
     *
105
     * This is an experiment to see if we can do something along the lines
106
     * of the University of Tokyo SGC in a less intrusive, though probably
107
     * also less performant, way.
108
     */
109
    void GC_do_parallel_mark();
110
                /* inititate parallel marking.  */
111
 
112
    extern GC_bool GC_help_wanted;      /* Protected by mark lock       */
113
    extern unsigned GC_helper_count;    /* Number of running helpers.   */
114
                                        /* Protected by mark lock       */
115
    extern unsigned GC_active_count;    /* Number of active helpers.    */
116
                                        /* Protected by mark lock       */
117
                                        /* May increase and decrease    */
118
                                        /* within each mark cycle.  But */
119
                                        /* once it returns to 0, it     */
120
                                        /* stays zero for the cycle.    */
121
    /* GC_mark_stack_top is also protected by mark lock.        */
122
    extern mse * VOLATILE GC_first_nonempty;
123
                                        /* Lowest entry on mark stack   */
124
                                        /* that may be nonempty.        */
125
                                        /* Updated only by initiating   */
126
                                        /* thread.                      */
127
    /*
128
     * GC_notify_all_marker() is used when GC_help_wanted is first set,
129
     * when the last helper becomes inactive,
130
     * when something is added to the global mark stack, and just after
131
     * GC_mark_no is incremented.
132
     * This could be split into multiple CVs (and probably should be to
133
     * scale to really large numbers of processors.)
134
     */
135
#endif /* PARALLEL_MARK */
136
 
137
/* Return a pointer to within 1st page of object.       */
138
/* Set *new_hdr_p to corr. hdr.                         */
139
#ifdef __STDC__
140
  ptr_t GC_find_start(ptr_t current, hdr *hhdr, hdr **new_hdr_p);
141
#else
142
  ptr_t GC_find_start();
143
#endif
144
 
145
mse * GC_signal_mark_stack_overflow GC_PROTO((mse *msp));
146
 
147
# ifdef GATHERSTATS
148
#   define ADD_TO_ATOMIC(sz) GC_atomic_in_use += (sz)
149
#   define ADD_TO_COMPOSITE(sz) GC_composite_in_use += (sz)
150
# else
151
#   define ADD_TO_ATOMIC(sz)
152
#   define ADD_TO_COMPOSITE(sz)
153
# endif
154
 
155
/* Push the object obj with corresponding heap block header hhdr onto   */
156
/* the mark stack.                                                      */
157
# define PUSH_OBJ(obj, hhdr, mark_stack_top, mark_stack_limit) \
158
{ \
159
    register word _descr = (hhdr) -> hb_descr; \
160
        \
161
    if (_descr == 0) { \
162
        ADD_TO_ATOMIC((hhdr) -> hb_sz); \
163
    } else { \
164
        ADD_TO_COMPOSITE((hhdr) -> hb_sz); \
165
        mark_stack_top++; \
166
        if (mark_stack_top >= mark_stack_limit) { \
167
          mark_stack_top = GC_signal_mark_stack_overflow(mark_stack_top); \
168
        } \
169
        mark_stack_top -> mse_start = (obj); \
170
        mark_stack_top -> mse_descr = _descr; \
171
    } \
172
}
173
 
174
/* Push the contents of current onto the mark stack if it is a valid    */
175
/* ptr to a currently unmarked object.  Mark it.                        */
176
/* If we assumed a standard-conforming compiler, we could probably      */
177
/* generate the exit_label transparently.                               */
178
# define PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
179
                       source, exit_label) \
180
{ \
181
    hdr * my_hhdr; \
182
    ptr_t my_current = current; \
183
 \
184
    GET_HDR(my_current, my_hhdr); \
185
    if (IS_FORWARDING_ADDR_OR_NIL(my_hhdr)) { \
186
         hdr * new_hdr = GC_invalid_header; \
187
         my_current = GC_find_start(my_current, my_hhdr, &new_hdr); \
188
         my_hhdr = new_hdr; \
189
    } \
190
    PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
191
                  source, exit_label, my_hhdr); \
192
exit_label: ; \
193
}
194
 
195
/* As above, but use header cache for header lookup.    */
196
# define HC_PUSH_CONTENTS(current, mark_stack_top, mark_stack_limit, \
197
                       source, exit_label) \
198
{ \
199
    hdr * my_hhdr; \
200
    ptr_t my_current = current; \
201
 \
202
    HC_GET_HDR(my_current, my_hhdr, source); \
203
    PUSH_CONTENTS_HDR(my_current, mark_stack_top, mark_stack_limit, \
204
                  source, exit_label, my_hhdr); \
205
exit_label: ; \
206
}
207
 
208
/* Set mark bit, exit if it was already set.    */
209
 
210
# ifdef USE_MARK_BYTES
211
    /* Unlike the mark bit case, there is a race here, and we may set   */
212
    /* the bit twice in the concurrent case.  This can result in the    */
213
    /* object being pushed twice.  But that's only a performance issue. */
214
#   define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
215
    { \
216
        register VOLATILE char * mark_byte_addr = \
217
                                hhdr -> hb_marks + ((displ) >> 1); \
218
        register char mark_byte = *mark_byte_addr; \
219
          \
220
        if (mark_byte) goto exit_label; \
221
        *mark_byte_addr = 1;  \
222
    }
223
# else
224
#   define SET_MARK_BIT_EXIT_IF_SET(hhdr,displ,exit_label) \
225
    { \
226
        register word * mark_word_addr = hhdr -> hb_marks + divWORDSZ(displ); \
227
          \
228
        OR_WORD_EXIT_IF_SET(mark_word_addr, (word)1 << modWORDSZ(displ), \
229
                            exit_label); \
230
    }
231
# endif /* USE_MARK_BYTES */
232
 
233
/* If the mark bit corresponding to current is not set, set it, and     */
234
/* push the contents of the object on the mark stack.  For a small      */
235
/* object we assume that current is the (possibly interior) pointer     */
236
/* to the object.  For large objects we assume that current points      */
237
/* to somewhere inside the first page of the object.  If                */
238
/* GC_all_interior_pointers is set, it may have been previously         */
239
/* adjusted to make that true.                                          */
240
# define PUSH_CONTENTS_HDR(current, mark_stack_top, mark_stack_limit, \
241
                           source, exit_label, hhdr) \
242
{ \
243
    int displ;  /* Displacement in block; first bytes, then words */ \
244
    int map_entry; \
245
    \
246
    displ = HBLKDISPL(current); \
247
    map_entry = MAP_ENTRY((hhdr -> hb_map), displ); \
248
    displ = BYTES_TO_WORDS(displ); \
249
    if (map_entry > CPP_MAX_OFFSET) { \
250
        if (map_entry == OFFSET_TOO_BIG) { \
251
          map_entry = displ % (hhdr -> hb_sz); \
252
          displ -= map_entry; \
253
          if (displ + (hhdr -> hb_sz) > BYTES_TO_WORDS(HBLKSIZE)) { \
254
            GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); \
255
            goto exit_label; \
256
          } \
257
        } else { \
258
          GC_ADD_TO_BLACK_LIST_NORMAL((word)current, source); goto exit_label; \
259
        } \
260
    } else { \
261
        displ -= map_entry; \
262
    } \
263
    GC_ASSERT(displ >= 0 && displ < MARK_BITS_PER_HBLK); \
264
    SET_MARK_BIT_EXIT_IF_SET(hhdr, displ, exit_label); \
265
    GC_STORE_BACK_PTR((ptr_t)source, (ptr_t)HBLKPTR(current) \
266
                                      + WORDS_TO_BYTES(displ)); \
267
    PUSH_OBJ(((word *)(HBLKPTR(current)) + displ), hhdr, \
268
             mark_stack_top, mark_stack_limit) \
269
}
270
 
271
#if defined(PRINT_BLACK_LIST) || defined(KEEP_BACK_PTRS)
272
#   define PUSH_ONE_CHECKED_STACK(p, source) \
273
        GC_mark_and_push_stack(p, (ptr_t)(source))
274
#else
275
#   define PUSH_ONE_CHECKED_STACK(p, source) \
276
        GC_mark_and_push_stack(p)
277
#endif
278
 
279
/*
280
 * Push a single value onto mark stack. Mark from the object pointed to by p.
281
 * Invoke FIXUP_POINTER(p) before any further processing.
282
 * P is considered valid even if it is an interior pointer.
283
 * Previously marked objects are not pushed.  Hence we make progress even
284
 * if the mark stack overflows.
285
 */
286
 
287
# if NEED_FIXUP_POINTER
288
    /* Try both the raw version and the fixed up one.   */
289
#   define GC_PUSH_ONE_STACK(p, source) \
290
      if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr     \
291
         && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) {      \
292
         PUSH_ONE_CHECKED_STACK(p, source);     \
293
      } \
294
      FIXUP_POINTER(p); \
295
      if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr     \
296
         && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) {      \
297
         PUSH_ONE_CHECKED_STACK(p, source);     \
298
      }
299
# else /* !NEED_FIXUP_POINTER */
300
#   define GC_PUSH_ONE_STACK(p, source) \
301
      if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr     \
302
         && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) {      \
303
         PUSH_ONE_CHECKED_STACK(p, source);     \
304
      }
305
# endif
306
 
307
 
308
/*
309
 * As above, but interior pointer recognition as for
310
 * normal for heap pointers.
311
 */
312
# define GC_PUSH_ONE_HEAP(p,source) \
313
    FIXUP_POINTER(p); \
314
    if ((ptr_t)(p) >= (ptr_t)GC_least_plausible_heap_addr       \
315
         && (ptr_t)(p) < (ptr_t)GC_greatest_plausible_heap_addr) {      \
316
            GC_mark_stack_top = GC_mark_and_push( \
317
                            (GC_PTR)(p), GC_mark_stack_top, \
318
                            GC_mark_stack_limit, (GC_PTR *)(source)); \
319
    }
320
 
321
/* Mark starting at mark stack entry top (incl.) down to        */
322
/* mark stack entry bottom (incl.).  Stop after performing      */
323
/* about one page worth of work.  Return the new mark stack     */
324
/* top entry.                                                   */
325
mse * GC_mark_from GC_PROTO((mse * top, mse * bottom, mse *limit));
326
 
327
#define MARK_FROM_MARK_STACK() \
328
        GC_mark_stack_top = GC_mark_from(GC_mark_stack_top, \
329
                                         GC_mark_stack, \
330
                                         GC_mark_stack + GC_mark_stack_size);
331
 
332
/*
333
 * Mark from one finalizable object using the specified
334
 * mark proc. May not mark the object pointed to by
335
 * real_ptr. That is the job of the caller, if appropriate
336
 */
337
# define GC_MARK_FO(real_ptr, mark_proc) \
338
{ \
339
    (*(mark_proc))(real_ptr); \
340
    while (!GC_mark_stack_empty()) MARK_FROM_MARK_STACK(); \
341
    if (GC_mark_state != MS_NONE) { \
342
        GC_set_mark_bit(real_ptr); \
343
        while (!GC_mark_some((ptr_t)0)) {} \
344
    } \
345
}
346
 
347
extern GC_bool GC_mark_stack_too_small;
348
                                /* We need a larger mark stack.  May be */
349
                                /* set by client supplied mark routines.*/
350
 
351
typedef int mark_state_t;       /* Current state of marking, as follows:*/
352
                                /* Used to remember where we are during */
353
                                /* concurrent marking.                  */
354
 
355
                                /* We say something is dirty if it was  */
356
                                /* written since the last time we       */
357
                                /* retrieved dirty bits.  We say it's   */
358
                                /* grungy if it was marked dirty in the */
359
                                /* last set of bits we retrieved.       */
360
 
361
                                /* Invariant I: all roots and marked    */
362
                                /* objects p are either dirty, or point */
363
                                /* to objects q that are either marked  */
364
                                /* or a pointer to q appears in a range */
365
                                /* on the mark stack.                   */
366
 
367
# define MS_NONE 0              /* No marking in progress. I holds.     */
368
                                /* Mark stack is empty.                 */
369
 
370
# define MS_PUSH_RESCUERS 1     /* Rescuing objects are currently       */
371
                                /* being pushed.  I holds, except       */
372
                                /* that grungy roots may point to       */
373
                                /* unmarked objects, as may marked      */
374
                                /* grungy objects above scan_ptr.       */
375
 
376
# define MS_PUSH_UNCOLLECTABLE 2
377
                                /* I holds, except that marked          */
378
                                /* uncollectable objects above scan_ptr */
379
                                /* may point to unmarked objects.       */
380
                                /* Roots may point to unmarked objects  */
381
 
382
# define MS_ROOTS_PUSHED 3      /* I holds, mark stack may be nonempty  */
383
 
384
# define MS_PARTIALLY_INVALID 4 /* I may not hold, e.g. because of M.S. */
385
                                /* overflow.  However marked heap       */
386
                                /* objects below scan_ptr point to      */
387
                                /* marked or stacked objects.           */
388
 
389
# define MS_INVALID 5           /* I may not hold.                      */
390
 
391
extern mark_state_t GC_mark_state;
392
 
393
#endif  /* GC_PMARK_H */
394
 

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