| /* |
| * 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" |
| |
| /* Consider pointers that are offset bytes displaced from the beginning */ |
| /* of an object to be valid. */ |
| |
| void GC_register_displacement(size_t offset) |
| { |
| DCL_LOCK_STATE; |
| |
| LOCK(); |
| GC_register_displacement_inner(offset); |
| UNLOCK(); |
| } |
| |
| void GC_register_displacement_inner(size_t offset) |
| { |
| if (offset >= VALID_OFFSET_SZ) { |
| 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; |
| } |
| } |
| |
| #ifdef MARK_BIT_PER_GRANULE |
| /* Add a heap block map for objects of size granules to obj_map. */ |
| /* Return FALSE on failure. */ |
| /* A size of 0 granules is used for large objects. */ |
| GC_bool GC_add_map_entry(size_t granules) |
| { |
| unsigned displ; |
| short * new_map; |
| |
| if (granules > BYTES_TO_GRANULES(MAXOBJBYTES)) granules = 0; |
| if (GC_obj_map[granules] != 0) { |
| return(TRUE); |
| } |
| new_map = (short *)GC_scratch_alloc(MAP_LEN * sizeof(short)); |
| if (new_map == 0) return(FALSE); |
| if (GC_print_stats) |
| GC_printf("Adding block map for size of %u granules (%u bytes)\n", |
| (unsigned)granules, (unsigned)(GRANULES_TO_BYTES(granules))); |
| if (granules == 0) { |
| for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) { |
| new_map[displ] = 1; /* Nonzero to get us out of marker fast path. */ |
| } |
| } else { |
| for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) { |
| new_map[displ] = (short)(displ % granules); |
| } |
| } |
| GC_obj_map[granules] = new_map; |
| return(TRUE); |
| } |
| #endif |
| |
| static GC_bool offsets_initialized = FALSE; |
| |
| void GC_initialize_offsets(void) |
| { |
| if (!offsets_initialized) { |
| int i; |
| if (GC_all_interior_pointers) { |
| for (i = 0; i < VALID_OFFSET_SZ; ++i) GC_valid_offsets[i] = TRUE; |
| } |
| offsets_initialized = TRUE; |
| } |
| } |