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authorIvan Maidanski <ivmai@mail.ru>2011-07-26 12:48:42 +0200
committerIvan Maidanski <ivmai@mail.ru>2011-07-26 12:48:42 +0200
commit7fd4efa1d0dbab63e6d9bddd1d72fa4aafc8ad52 (patch)
treef784c1f66c09df5e17aeb85cf5862b459d455ebd /obj_map.c
gc4.1 tarball importgc4_1
Diffstat (limited to 'obj_map.c')
-rw-r--r--obj_map.c137
1 files changed, 137 insertions, 0 deletions
diff --git a/obj_map.c b/obj_map.c
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+++ b/obj_map.c
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+/*
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991, 1992 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 1:59 pm PDT */
+
+/* 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 "gc_priv.h"
+
+char * 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 = 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. */
+void GC_register_displacement(offset)
+word offset;
+{
+# ifndef ALL_INTERIOR_POINTERS
+ DCL_LOCK_STATE;
+
+ DISABLE_SIGNALS();
+ LOCK();
+ GC_register_displacement_inner(offset);
+ UNLOCK();
+ ENABLE_SIGNALS();
+# endif
+}
+
+void GC_register_displacement_inner(offset)
+word offset;
+{
+# ifndef ALL_INTERIOR_POINTERS
+ register unsigned i;
+
+ if (offset > MAX_OFFSET) {
+ ABORT("Bad argument to GC_register_displacement");
+ }
+ if (!GC_valid_offsets[offset]) {
+ GC_valid_offsets[offset] = TRUE;
+ GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
+ for (i = 0; i <= MAXOBJSZ; i++) {
+ if (GC_obj_map[i] != 0) {
+ if (i == 0) {
+ GC_obj_map[i][offset + HDR_BYTES] = (char)BYTES_TO_WORDS(offset);
+ } else {
+ register unsigned j;
+ register unsigned lb = WORDS_TO_BYTES(i);
+
+ if (offset < lb) {
+ for (j = offset + HDR_BYTES; j < HBLKSIZE; j += lb) {
+ GC_obj_map[i][j] = (char)BYTES_TO_WORDS(offset);
+ }
+ }
+ }
+ }
+ }
+ }
+# endif
+}
+
+
+/* Add a heap block map for objects of size sz to obj_map. */
+/* Return FALSE on failure. */
+bool GC_add_map_entry(sz)
+word sz;
+{
+ register unsigned obj_start;
+ register unsigned displ;
+ register char * new_map;
+
+ if (sz > MAXOBJSZ) sz = 0;
+ if (GC_obj_map[sz] != 0) {
+ return(TRUE);
+ }
+ new_map = 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 <= MAX_OFFSET; displ++) {
+ if (OFFSET_VALID(displ)) {
+ MAP_ENTRY(new_map,displ+HDR_BYTES) = BYTES_TO_WORDS(displ);
+ }
+ }
+ } else {
+ for (obj_start = HDR_BYTES;
+ 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(new_map, obj_start + displ) =
+ BYTES_TO_WORDS(displ);
+ }
+ }
+ }
+ }
+ GC_obj_map[sz] = new_map;
+ return(TRUE);
+}