Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

152 lines (133 sloc) 4.196 kB
/*
* Copyright (c) 1992-1994 by Xerox Corporation. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
/* Boehm, May 19, 1994 2:07 pm PDT */
# ifdef CHECKSUMS
# include "gc_priv.h"
/* This is debugging code intended to verify the results of dirty bit */
/* computations. Works only in a single threaded environment. */
/* We assume that stubborn objects are changed only when they are */
/* enabled for writing. (Certain kinds of writing are actually */
/* safe under other conditions.) */
# define NSUMS 2000
# define OFFSET 100000
typedef struct {
bool new_valid;
word old_sum;
word new_sum;
struct hblk * block; /* Block to which this refers + OFFSET */
/* to hide it from colector. */
} page_entry;
page_entry GC_sums [NSUMS];
word GC_checksum(h)
struct hblk *h;
{
register word *p = (word *)h;
register word *lim = (word *)(h+1);
register word result = 0;
while (p < lim) {
result += *p++;
}
return(result);
}
# ifdef STUBBORN_ALLOC
/* Check whether a stubborn object from the given block appears on */
/* the appropriate free list. */
bool GC_on_free_list(h)
struct hblk *h;
{
register hdr * hhdr = HDR(h);
register int sz = hhdr -> hb_sz;
ptr_t p;
if (sz > MAXOBJSZ) return(FALSE);
for (p = GC_sobjfreelist[sz]; p != 0; p = obj_link(p)) {
if (HBLKPTR(p) == h) return(TRUE);
}
return(FALSE);
}
# endif
int GC_n_dirty_errors;
int GC_n_changed_errors;
int GC_n_clean;
int GC_n_dirty;
void GC_update_check_page(h, index)
struct hblk *h;
int index;
{
page_entry *pe = GC_sums + index;
register hdr * hhdr = HDR(h);
if (pe -> block != 0 && pe -> block != h + OFFSET) ABORT("goofed");
pe -> old_sum = pe -> new_sum;
pe -> new_sum = GC_checksum(h);
if (GC_page_was_dirty(h)) {
GC_n_dirty++;
} else {
GC_n_clean++;
}
if (pe -> new_valid && pe -> old_sum != pe -> new_sum) {
if (!GC_page_was_dirty(h)) {
/* Set breakpoint here */GC_n_dirty_errors++;
}
# ifdef STUBBORN_ALLOC
if (!IS_FORWARDING_ADDR_OR_NIL(hhdr)
&& hhdr -> hb_map != GC_invalid_map
&& hhdr -> hb_obj_kind == STUBBORN
&& !GC_page_was_changed(h)
&& !GC_on_free_list(h)) {
/* if GC_on_free_list(h) then reclaim may have touched it */
/* without any allocations taking place. */
/* Set breakpoint here */GC_n_changed_errors++;
}
# endif
}
pe -> new_valid = TRUE;
pe -> block = h + OFFSET;
}
/* Should be called immediately after GC_read_dirty and GC_read_changed. */
void GC_check_dirty()
{
register int index;
register int i;
register struct hblk *h;
register ptr_t start;
GC_n_dirty_errors = 0;
GC_n_changed_errors = 0;
GC_n_clean = 0;
GC_n_dirty = 0;
index = 0;
for (i = 0; i < GC_n_heap_sects; i++) {
start = GC_heap_sects[i].hs_start;
for (h = (struct hblk *)start;
h < (struct hblk *)(start + GC_heap_sects[i].hs_bytes);
h++) {
GC_update_check_page(h, index);
index++;
if (index >= NSUMS) goto out;
}
}
out:
GC_printf2("Checked %lu clean and %lu dirty pages\n",
(unsigned long) GC_n_clean, (unsigned long) GC_n_dirty);
if (GC_n_dirty_errors > 0) {
GC_printf1("Found %lu dirty bit errors\n",
(unsigned long)GC_n_dirty_errors);
}
if (GC_n_changed_errors > 0) {
GC_printf1("Found %lu changed bit errors\n",
(unsigned long)GC_n_changed_errors);
}
}
# else
extern int GC_quiet;
/* ANSI C doesn't allow translation units to be empty. */
/* So we guarantee this one is nonempty. */
# endif /* CHECKSUMS */
Jump to Line
Something went wrong with that request. Please try again.