2 * Copyright (c) 1992-1994 by Xerox Corporation. All rights reserved.
4 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
5 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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.
13 /* Boehm, March 29, 1995 12:51 pm PST */
16 # include "private/gc_priv.h"
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.) */
25 # define OFFSET 0x10000
31 struct hblk * block; /* Block to which this refers + OFFSET */
32 /* to hide it from collector. */
35 page_entry GC_sums [NSUMS];
40 register word *p = (word *)h;
41 register word *lim = (word *)(h+1);
42 register word result = 0;
47 return(result | 0x80000000 /* doesn't look like pointer */);
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)
57 int sz = BYTES_TO_WORDS(hhdr -> hb_sz);
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);
68 int GC_n_dirty_errors;
69 int GC_n_changed_errors;
73 void GC_update_check_page(struct hblk *h, int index)
75 page_entry *pe = GC_sums + index;
76 register hdr * hhdr = HDR(h);
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);
87 if (GC_page_was_dirty(h)) {
93 while (IS_FORWARDING_ADDR_OR_NIL(hhdr) && hhdr != 0) {
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++;
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++;
114 pe -> new_valid = TRUE;
115 pe -> block = h + OFFSET;
118 unsigned long GC_bytes_in_used_blocks;
120 void GC_add_block(h, dummy)
125 bytes = hhdr -> hb_sz;
128 bytes &= ~(HBLKSIZE-1);
129 GC_bytes_in_used_blocks += bytes;
132 void GC_check_blocks()
134 unsigned long bytes_in_free_blocks = GC_large_free_bytes;
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");
146 /* Should be called immediately after GC_read_dirty and GC_read_changed. */
147 void GC_check_dirty()
151 register struct hblk *h;
152 register ptr_t start;
156 GC_n_dirty_errors = 0;
157 GC_n_changed_errors = 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);
167 GC_update_check_page(h, index);
169 if (index >= NSUMS) goto 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);
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");
185 "Also expect 1 per thread currently allocating a stubborn obj.\n");
193 /* ANSI C doesn't allow translation units to be empty. */
194 /* So we guarantee this one is nonempty. */
196 # endif /* CHECKSUMS */