diff options
Diffstat (limited to 'boehm-gc/obj_map.c')
| -rw-r--r-- | boehm-gc/obj_map.c | 147 |
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); +} |