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Diffstat (limited to 'lib/malloc/table.h')
| -rw-r--r-- | lib/malloc/table.h | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/lib/malloc/table.h b/lib/malloc/table.h new file mode 100644 index 0000000..41ce9f7 --- /dev/null +++ b/lib/malloc/table.h @@ -0,0 +1,105 @@ +/* table.h - definitions for tables for keeping track of allocated memory */ + +/* Copyright (C) 2001-2003 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne-Again SHell. + + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef _MTABLE_H +#define _MTABLE_H + +#include "imalloc.h" + +#ifdef MALLOC_REGISTER + +/* values for flags byte. */ +#define MT_ALLOC 0x01 +#define MT_FREE 0x02 + +/* + * Memory table entry. + * + * MEM is the address of the allocated pointer. + * SIZE is the requested allocation size. + * FLAGS includes either MT_ALLOC (MEM is allocated) or MT_FREE (MEM is + * not allocated). Other flags later. + * FUNC is set to the name of the function doing the allocation (from the + * `tag' argument to register_alloc(). + * FILE and LINE are the filename and line number of the last allocation + * and free (depending on STATUS) of MEM. + * NALLOC and NFREE are incremented on each allocation that returns MEM or + * each free of MEM, respectively (way to keep track of memory reuse + * and how well the free lists are working). + * + */ +typedef struct mr_table { + PTR_T mem; + size_t size; + char flags; + const char *func; + const char *file; + int line; + int nalloc, nfree; +} mr_table_t; + +#define REG_TABLE_SIZE 8192 + +extern mr_table_t *mr_table_entry __P((PTR_T)); +extern void mregister_alloc __P((const char *, PTR_T, size_t, const char *, int)); +extern void mregister_free __P((PTR_T, int, const char *, int)); +extern void mregister_describe_mem (); +extern void mregister_dump_table __P((void)); +extern void mregister_table_init __P((void)); + +/* NOTE: HASH_MIX taken from dmalloc (http://dmalloc.com) */ + +/* + * void HASH_MIX + * + * DESCRIPTION: + * + * Mix 3 32-bit values reversibly. For every delta with one or two + * bits set, and the deltas of all three high bits or all three low + * bits, whether the original value of a,b,c is almost all zero or is + * uniformly distributed. + * + * If HASH_MIX() is run forward or backward, at least 32 bits in a,b,c + * have at least 1/4 probability of changing. If mix() is run + * forward, every bit of c will change between 1/3 and 2/3 of the + * time. (Well, 22/100 and 78/100 for some 2-bit deltas.) + * + * HASH_MIX() takes 36 machine instructions, but only 18 cycles on a + * superscalar machine (like a Pentium or a Sparc). No faster mixer + * seems to work, that's the result of my brute-force search. There + * were about 2^68 hashes to choose from. I only tested about a + * billion of those. + */ +#define HASH_MIX(a, b, c) \ + do { \ + a -= b; a -= c; a ^= (c >> 13); \ + b -= c; b -= a; b ^= (a << 8); \ + c -= a; c -= b; c ^= (b >> 13); \ + a -= b; a -= c; a ^= (c >> 12); \ + b -= c; b -= a; b ^= (a << 16); \ + c -= a; c -= b; c ^= (b >> 5); \ + a -= b; a -= c; a ^= (c >> 3); \ + b -= c; b -= a; b ^= (a << 10); \ + c -= a; c -= b; c ^= (b >> 15); \ + } while(0) + +#endif /* MALLOC_REGISTER */ + +#endif /* _MTABLE_H */ |