summaryrefslogtreecommitdiff
path: root/boehm-gc/obj_map.c
diff options
context:
space:
mode:
Diffstat (limited to 'boehm-gc/obj_map.c')
-rw-r--r--boehm-gc/obj_map.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/boehm-gc/obj_map.c b/boehm-gc/obj_map.c
new file mode 100644
index 000000000..d002d65b4
--- /dev/null
+++ b/boehm-gc/obj_map.c
@@ -0,0 +1,147 @@
+/*
+ * 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);
+}