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/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991, 1992 by Xerox Corporation. All rights reserved.
* Copyright (c) 1999-2001 by Hewlett-Packard Company. 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.
*/
/* Routines for maintaining maps describing heap block
* layouts for various object sizes. Allows fast pointer validity checks
* and fast location of object start locations on machines (such as SPARC)
* with slow division.
*/
# include "private/gc_priv.h"
map_entry_type * GC_invalid_map = 0;
/* Invalidate the object map associated with a block. Free blocks */
/* are identified by invalid maps. */
void GC_invalidate_map(hhdr)
hdr *hhdr;
{
register int displ;
if (GC_invalid_map == 0) {
GC_invalid_map = (map_entry_type *)GC_scratch_alloc(MAP_SIZE);
if (GC_invalid_map == 0) {
GC_err_printf0(
"Cant initialize GC_invalid_map: insufficient memory\n");
EXIT();
}
for (displ = 0; displ < HBLKSIZE; displ++) {
MAP_ENTRY(GC_invalid_map, displ) = OBJ_INVALID;
}
}
hhdr -> hb_map = GC_invalid_map;
}
/* Consider pointers that are offset bytes displaced from the beginning */
/* of an object to be valid. */
# if defined(__STDC__) || defined(__cplusplus)
void GC_register_displacement(GC_word offset)
# else
void GC_register_displacement(offset)
GC_word offset;
# endif
{
DCL_LOCK_STATE;
DISABLE_SIGNALS();
LOCK();
GC_register_displacement_inner(offset);
UNLOCK();
ENABLE_SIGNALS();
}
void GC_register_displacement_inner(offset)
word offset;
{
register unsigned i;
word map_entry = BYTES_TO_WORDS(offset);
if (offset >= VALID_OFFSET_SZ) {
ABORT("Bad argument to GC_register_displacement");
}
if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
if (!GC_valid_offsets[offset]) {
GC_valid_offsets[offset] = TRUE;
GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
if (!GC_all_interior_pointers) {
for (i = 0; i <= MAXOBJSZ; i++) {
if (GC_obj_map[i] != 0) {
if (i == 0) {
GC_obj_map[i][offset] = (map_entry_type)map_entry;
} else {
register unsigned j;
register unsigned lb = WORDS_TO_BYTES(i);
if (offset < lb) {
for (j = offset; j < HBLKSIZE; j += lb) {
GC_obj_map[i][j] = (map_entry_type)map_entry;
}
}
}
}
}
}
}
}
/* Add a heap block map for objects of size sz to obj_map. */
/* Return FALSE on failure. */
GC_bool GC_add_map_entry(sz)
word sz;
{
register unsigned obj_start;
register unsigned displ;
register map_entry_type * new_map;
word map_entry;
if (sz > MAXOBJSZ) sz = 0;
if (GC_obj_map[sz] != 0) {
return(TRUE);
}
new_map = (map_entry_type *)GC_scratch_alloc(MAP_SIZE);
if (new_map == 0) return(FALSE);
# ifdef PRINTSTATS
GC_printf1("Adding block map for size %lu\n", (unsigned long)sz);
# endif
for (displ = 0; displ < HBLKSIZE; displ++) {
MAP_ENTRY(new_map,displ) = OBJ_INVALID;
}
if (sz == 0) {
for(displ = 0; displ <= HBLKSIZE; displ++) {
if (OFFSET_VALID(displ)) {
map_entry = BYTES_TO_WORDS(displ);
if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
MAP_ENTRY(new_map,displ) = (map_entry_type)map_entry;
}
}
} else {
for (obj_start = 0;
obj_start + WORDS_TO_BYTES(sz) <= HBLKSIZE;
obj_start += WORDS_TO_BYTES(sz)) {
for (displ = 0; displ < WORDS_TO_BYTES(sz); displ++) {
if (OFFSET_VALID(displ)) {
map_entry = BYTES_TO_WORDS(displ);
if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
MAP_ENTRY(new_map, obj_start + displ) =
(map_entry_type)map_entry;
}
}
}
}
GC_obj_map[sz] = new_map;
return(TRUE);
}
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