ceph/src/boost/tools/build/src/engine/boehm_gc/checksums.c

   1 /*
   2  * Copyright (c) 1992-1994 by Xerox Corporation.  All rights reserved.
   3  *
   4  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   5  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   6  *
   7  * Permission is hereby granted to use or copy this program
   8  * for any purpose,  provided the above notices are retained on all copies.
   9  * Permission to modify the code and to distribute modified code is granted,
  10  * provided the above notices are retained, and a notice that the code was
  11  * modified is included with the above copyright notice.
  12  */
  13 /* Boehm, March 29, 1995 12:51 pm PST */
  14 # ifdef CHECKSUMS
  15
  16 # include "private/gc_priv.h"
  17
  18 /* This is debugging code intended to verify the results of dirty bit   */
  19 /* computations. Works only in a single threaded environment.           */
  20 /* We assume that stubborn objects are changed only when they are       */
  21 /* enabled for writing.  (Certain kinds of writing are actually         */
  22 /* safe under other conditions.)                                        */
  23 # define NSUMS 10000
  24
  25 # define OFFSET 0x10000
  26
  27 typedef struct {
  28         GC_bool new_valid;
  29         word old_sum;
  30         word new_sum;
  31         struct hblk * block;    /* Block to which this refers + OFFSET  */
  32                                 /* to hide it from collector.           */
  33 } page_entry;
  34
  35 page_entry GC_sums [NSUMS];
  36
  37 word GC_checksum(h)
  38 struct hblk *h;
  39 {
  40     register word *p = (word *)h;
  41     register word *lim = (word *)(h+1);
  42     register word result = 0;
  43
  44     while (p < lim) {
  45         result += *p++;
  46     }
  47     return(result | 0x80000000 /* doesn't look like pointer */);
  48 }
  49
  50 # ifdef STUBBORN_ALLOC
  51 /* Check whether a stubborn object from the given block appears on      */
  52 /* the appropriate free list.                                           */
  53 GC_bool GC_on_free_list(struct hblk *h)
  54 struct hblk *h;
  55 {
  56     hdr * hhdr = HDR(h);
  57     int sz = BYTES_TO_WORDS(hhdr -> hb_sz);
  58     ptr_t p;
  59
  60     if (sz > MAXOBJWORDS) return(FALSE);
  61     for (p = GC_sobjfreelist[sz]; p != 0; p = obj_link(p)) {
  62         if (HBLKPTR(p) == h) return(TRUE);
  63     }
  64     return(FALSE);
  65 }
  66 # endif
  67
  68 int GC_n_dirty_errors;
  69 int GC_n_changed_errors;
  70 int GC_n_clean;
  71 int GC_n_dirty;
  72
  73 void GC_update_check_page(struct hblk *h, int index)
  74 {
  75     page_entry *pe = GC_sums + index;
  76     register hdr * hhdr = HDR(h);
  77     struct hblk *b;
  78
  79     if (pe -> block != 0 && pe -> block != h + OFFSET) ABORT("goofed");
  80     pe -> old_sum = pe -> new_sum;
  81     pe -> new_sum = GC_checksum(h);
  82 #   if !defined(MSWIN32) && !defined(MSWINCE)
  83         if (pe -> new_sum != 0x80000000 && !GC_page_was_ever_dirty(h)) {
  84             GC_printf("GC_page_was_ever_dirty(%p) is wrong\n", h);
  85         }
  86 #   endif
  87     if (GC_page_was_dirty(h)) {
  88         GC_n_dirty++;
  89     } else {
  90         GC_n_clean++;
  91     }
  92     b = h;
  93     while (IS_FORWARDING_ADDR_OR_NIL(hhdr) && hhdr != 0) {
  94         b -= (word)hhdr;
  95         hhdr = HDR(b);
  96     }
  97     if (pe -> new_valid
  98         && hhdr != 0 && hhdr -> hb_descr != 0 /* may contain pointers */
  99         && pe -> old_sum != pe -> new_sum) {
 100         if (!GC_page_was_dirty(h) || !GC_page_was_ever_dirty(h)) {
 101             /* Set breakpoint here */GC_n_dirty_errors++;
 102         }
 103 #       ifdef STUBBORN_ALLOC
 104           if (!HBLK_IS_FREE(hhdr)
 105             && hhdr -> hb_obj_kind == STUBBORN
 106             && !GC_page_was_changed(h)
 107             && !GC_on_free_list(h)) {
 108             /* if GC_on_free_list(h) then reclaim may have touched it   */
 109             /* without any allocations taking place.                    */
 110             /* Set breakpoint here */GC_n_changed_errors++;
 111           }
 112 #       endif
 113     }
 114     pe -> new_valid = TRUE;
 115     pe -> block = h + OFFSET;
 116 }
 117
 118 unsigned long GC_bytes_in_used_blocks;
 119
 120 void GC_add_block(h, dummy)
 121 struct hblk *h;
 122 word dummy;
 123 {
 124    hdr * hhdr = HDR(h);
 125    bytes = hhdr -> hb_sz;
 126
 127    bytes += HBLKSIZE-1;
 128    bytes &= ~(HBLKSIZE-1);
 129    GC_bytes_in_used_blocks += bytes;
 130 }
 131
 132 void GC_check_blocks()
 133 {
 134     unsigned long bytes_in_free_blocks = GC_large_free_bytes;
 135
 136     GC_bytes_in_used_blocks = 0;
 137     GC_apply_to_all_blocks(GC_add_block, (word)0);
 138     GC_printf("GC_bytes_in_used_blocks = %lu, bytes_in_free_blocks = %lu ",
 139               GC_bytes_in_used_blocks, bytes_in_free_blocks);
 140     GC_printf("GC_heapsize = %lu\n", (unsigned long)GC_heapsize);
 141     if (GC_bytes_in_used_blocks + bytes_in_free_blocks != GC_heapsize) {
 142         GC_printf("LOST SOME BLOCKS!!\n");
 143     }
 144 }
 145
 146 /* Should be called immediately after GC_read_dirty and GC_read_changed. */
 147 void GC_check_dirty()
 148 {
 149     register int index;
 150     register unsigned i;
 151     register struct hblk *h;
 152     register ptr_t start;
 153
 154     GC_check_blocks();
 155
 156     GC_n_dirty_errors = 0;
 157     GC_n_changed_errors = 0;
 158     GC_n_clean = 0;
 159     GC_n_dirty = 0;
 160
 161     index = 0;
 162     for (i = 0; i < GC_n_heap_sects; i++) {
 163         start = GC_heap_sects[i].hs_start;
 164         for (h = (struct hblk *)start;
 165              h < (struct hblk *)(start + GC_heap_sects[i].hs_bytes);
 166              h++) {
 167              GC_update_check_page(h, index);
 168              index++;
 169              if (index >= NSUMS) goto out;
 170         }
 171     }
 172 out:
 173     GC_printf("Checked %lu clean and %lu dirty pages\n",
 174               (unsigned long) GC_n_clean, (unsigned long) GC_n_dirty);
 175     if (GC_n_dirty_errors > 0) {
 176         GC_printf("Found %lu dirty bit errors\n",
 177                   (unsigned long)GC_n_dirty_errors);
 178     }
 179     if (GC_n_changed_errors > 0) {
 180         GC_printf("Found %lu changed bit errors\n",
 181                   (unsigned long)GC_n_changed_errors);
 182         GC_printf("These may be benign (provoked by nonpointer changes)\n");
 183 #       ifdef THREADS
 184             GC_printf(
 185             "Also expect 1 per thread currently allocating a stubborn obj.\n");
 186 #       endif
 187     }
 188 }
 189
 190 # else
 191
 192 extern int GC_quiet;
 193         /* ANSI C doesn't allow translation units to be empty.  */
 194         /* So we guarantee this one is nonempty.                */
 195
 196 # endif /* CHECKSUMS */