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 */
19 # include "private/gc_priv.h"
21 /* This is debugging code intended to verify the results of dirty bit */
22 /* computations. Works only in a single threaded environment. */
23 /* We assume that stubborn objects are changed only when they are */
24 /* enabled for writing. (Certain kinds of writing are actually */
25 /* safe under other conditions.) */
28 # define OFFSET 0x10000
34 struct hblk * block; /* Block to which this refers + OFFSET */
35 /* to hide it from collector. */
38 page_entry GC_sums [NSUMS];
43 register word *p = (word *)h;
44 register word *lim = (word *)(h+1);
45 register word result = 0;
50 return(result | 0x80000000 /* doesn't look like pointer */);
53 # ifdef STUBBORN_ALLOC
54 /* Check whether a stubborn object from the given block appears on */
55 /* the appropriate free list. */
56 GC_bool GC_on_free_list(h)
59 register hdr * hhdr = HDR(h);
60 register int sz = hhdr -> hb_sz;
63 if (sz > MAXOBJSZ) return(FALSE);
64 for (p = GC_sobjfreelist[sz]; p != 0; p = obj_link(p)) {
65 if (HBLKPTR(p) == h) return(TRUE);
71 int GC_n_dirty_errors;
72 int GC_n_changed_errors;
76 void GC_update_check_page(h, index)
80 page_entry *pe = GC_sums + index;
81 register hdr * hhdr = HDR(h);
84 if (pe -> block != 0 && pe -> block != h + OFFSET) ABORT("goofed");
85 pe -> old_sum = pe -> new_sum;
86 pe -> new_sum = GC_checksum(h);
87 # if !defined(MSWIN32) && !defined(MSWINCE)
88 if (pe -> new_sum != 0x80000000 && !GC_page_was_ever_dirty(h)) {
89 GC_printf1("GC_page_was_ever_dirty(0x%lx) is wrong\n",
93 if (GC_page_was_dirty(h)) {
99 while (IS_FORWARDING_ADDR_OR_NIL(hhdr) && hhdr != 0) {
104 && hhdr != 0 && hhdr -> hb_descr != 0 /* may contain pointers */
105 && pe -> old_sum != pe -> new_sum) {
106 if (!GC_page_was_dirty(h) || !GC_page_was_ever_dirty(h)) {
107 /* Set breakpoint here */GC_n_dirty_errors++;
109 # ifdef STUBBORN_ALLOC
110 if ( hhdr -> hb_map != GC_invalid_map
111 && hhdr -> hb_obj_kind == STUBBORN
112 && !GC_page_was_changed(h)
113 && !GC_on_free_list(h)) {
114 /* if GC_on_free_list(h) then reclaim may have touched it */
115 /* without any allocations taking place. */
116 /* Set breakpoint here */GC_n_changed_errors++;
120 pe -> new_valid = TRUE;
121 pe -> block = h + OFFSET;
124 word GC_bytes_in_used_blocks;
126 void GC_add_block(h, dummy)
130 register hdr * hhdr = HDR(h);
131 register bytes = WORDS_TO_BYTES(hhdr -> hb_sz);
134 bytes &= ~(HBLKSIZE-1);
135 GC_bytes_in_used_blocks += bytes;
138 void GC_check_blocks()
140 word bytes_in_free_blocks = GC_large_free_bytes;
142 GC_bytes_in_used_blocks = 0;
143 GC_apply_to_all_blocks(GC_add_block, (word)0);
144 GC_printf2("GC_bytes_in_used_blocks = %ld, bytes_in_free_blocks = %ld ",
145 GC_bytes_in_used_blocks, bytes_in_free_blocks);
146 GC_printf1("GC_heapsize = %ld\n", GC_heapsize);
147 if (GC_bytes_in_used_blocks + bytes_in_free_blocks != GC_heapsize) {
148 GC_printf0("LOST SOME BLOCKS!!\n");
152 /* Should be called immediately after GC_read_dirty and GC_read_changed. */
153 void GC_check_dirty()
157 register struct hblk *h;
158 register ptr_t start;
162 GC_n_dirty_errors = 0;
163 GC_n_changed_errors = 0;
168 for (i = 0; i < GC_n_heap_sects; i++) {
169 start = GC_heap_sects[i].hs_start;
170 for (h = (struct hblk *)start;
171 h < (struct hblk *)(start + GC_heap_sects[i].hs_bytes);
173 GC_update_check_page(h, index);
175 if (index >= NSUMS) goto out;
179 GC_printf2("Checked %lu clean and %lu dirty pages\n",
180 (unsigned long) GC_n_clean, (unsigned long) GC_n_dirty);
181 if (GC_n_dirty_errors > 0) {
182 GC_printf1("Found %lu dirty bit errors\n",
183 (unsigned long)GC_n_dirty_errors);
185 if (GC_n_changed_errors > 0) {
186 GC_printf1("Found %lu changed bit errors\n",
187 (unsigned long)GC_n_changed_errors);
188 GC_printf0("These may be benign (provoked by nonpointer changes)\n");
191 "Also expect 1 per thread currently allocating a stubborn obj.\n");
199 /* ANSI C doesn't allow translation units to be empty. */
200 /* So we guarantee this one is nonempty. */
202 # endif /* CHECKSUMS */