binutils-gdb/gdb/dictionary.h
Paul N. Hilfinger c4d840bdd6 Extend hashed symbol dictionaries to work with Ada
This patch allows Ada to speed up symbol lookup by using the facilities
in dictionary.[ch] for hashed lookups.  First, we generalize dictionary
search to allow clients to specify any matching function compatible with
the hashing function. Next, we modify the hashing algorithm so that symbols
that wild-match a name hash to the same value.  Finally, we modify Ada
symbol lookup to use these facilities.

Because this patch touches on a hashing algorithm used by other
languages, I took the precaution of doing a speed test on a list of
about 12000 identifiers (repeatedly inserting all of them into a table
and then doing a lookup on a million names at random, thus testing the
speed of the hashing algorithm and how well it distributed names).
There was actually a slight speedup, probably as a result of open-
coding some of the tests in msymbol_hash_iw.  By design, the revised
hashing algorithm produces the same results as the original on most
"normal" C identifiers.

We considered augmenting the dictionary interface still further by allowing
different hashing algorithms for different dictionaries, based on the
(supposed) language of the symbols in that dictionary.  While this produced
better isolation of the changes to Ada programs, the additional flexibility
also complicated the dictionary interface.  I'd prefer to keep things
simple for now.

Tested w/o regressions on Linux i686.

ChangeLog:

	gdb/
	* ada-lang.c (ada_match_name): Use new API for wild_match.
	(wild_match): Change API to be consistent with that of strcmp_iw;
	return 0 for a match, and switch operand order.
	(full_match): New function.
	(ada_add_block_symbols): Use dict_iter_match_{first,next} for
	matching to allow use of hashing.
	* dictionary.c (struct dict_vector): Generalize iter_name_first,
	iter_name_next ot iter_match_first, iter_match_next.
	(iter_name_first_hashed): Replace with iter_match_first_hashed.
	(iter_name_next_hashed): Replace with iter_match_next_hashed.
	(iter_name_first_linear): Replace with iter_match_first_linear.
	(iter_name_next_linear): Replace with iter_match_next_linear.
	(dict_iter_name_first): Re-implement to use dict_iter_match_first.
	(dict_iter_name_next): Re-implement to use dict_iter_match_next.
	(dict_iter_match_first): New function.
	(dict_iter_match_next): New function.
	(dict_hash): New function.
	* dictionary.h (dict_iter_match_first, dict_iter_match_next): Declare.
	* psymtab.c (ada_lookup_partial_symbol): Use new wild_match API.
2010-10-07 06:53:44 +00:00

180 lines
6.6 KiB
C

/* Routines for name->symbol lookups in GDB.
Copyright (C) 2003, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by David Carlton <carlton@bactrian.org> and by Kealia,
Inc.
This file is part of GDB.
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef DICTIONARY_H
#define DICTIONARY_H
/* An opaque type for dictionaries; only dictionary.c should know
about its innards. */
struct dictionary;
/* Other types needed for declarations. */
struct symbol;
struct obstack;
struct pending;
/* The creation functions for various implementations of
dictionaries. */
/* Create a dictionary implemented via a fixed-size hashtable. All
memory it uses is allocated on OBSTACK; the environment is
initialized from SYMBOL_LIST. */
extern struct dictionary *dict_create_hashed (struct obstack *obstack,
const struct pending
*symbol_list);
/* Create a dictionary implemented via a hashtable that grows as
necessary. The dictionary is initially empty; to add symbols to
it, call dict_add_symbol(). Call dict_free() when you're done with
it. */
extern struct dictionary *dict_create_hashed_expandable (void);
/* Create a dictionary implemented via a fixed-size array. All memory
it uses is allocated on OBSTACK; the environment is initialized
from the SYMBOL_LIST. The symbols are ordered in the same order
that they're found in SYMBOL_LIST. */
extern struct dictionary *dict_create_linear (struct obstack *obstack,
const struct pending
*symbol_list);
/* Create a dictionary implemented via an array that grows as
necessary. The dictionary is initially empty; to add symbols to
it, call dict_add_symbol(). Call dict_free() when you're done with
it. */
extern struct dictionary *dict_create_linear_expandable (void);
/* The functions providing the interface to dictionaries. Note that
the most common parts of the interface, namely symbol lookup, are
only provided via iterator functions. */
/* Free the memory used by a dictionary that's not on an obstack. (If
any.) */
extern void dict_free (struct dictionary *dict);
/* Add a symbol to an expandable dictionary. */
extern void dict_add_symbol (struct dictionary *dict, struct symbol *sym);
/* Is the dictionary empty? */
extern int dict_empty (struct dictionary *dict);
/* A type containing data that is used when iterating over all symbols
in a dictionary. Don't ever look at its innards; this type would
be opaque if we didn't need to be able to allocate it on the
stack. */
struct dict_iterator
{
/* The dictionary that this iterator is associated to. */
const struct dictionary *dict;
/* The next two members are data that is used in a way that depends
on DICT's implementation type. */
int index;
struct symbol *current;
};
/* Initialize ITERATOR to point at the first symbol in DICT, and
return that first symbol, or NULL if DICT is empty. */
extern struct symbol *dict_iterator_first (const struct dictionary *dict,
struct dict_iterator *iterator);
/* Advance ITERATOR, and return the next symbol, or NULL if there are
no more symbols. Don't call this if you've previously received
NULL from dict_iterator_first or dict_iterator_next on this
iteration. */
extern struct symbol *dict_iterator_next (struct dict_iterator *iterator);
/* Initialize ITERATOR to point at the first symbol in DICT whose
SYMBOL_SEARCH_NAME is NAME (as tested using strcmp_iw), and return
that first symbol, or NULL if there are no such symbols. */
extern struct symbol *dict_iter_name_first (const struct dictionary *dict,
const char *name,
struct dict_iterator *iterator);
/* Advance ITERATOR to point at the next symbol in DICT whose
SYMBOL_SEARCH_NAME is NAME (as tested using strcmp_iw), or NULL if
there are no more such symbols. Don't call this if you've
previously received NULL from dict_iterator_first or
dict_iterator_next on this iteration. And don't call it unless
ITERATOR was created by a previous call to dict_iter_name_first
with the same NAME. */
extern struct symbol *dict_iter_name_next (const char *name,
struct dict_iterator *iterator);
/* Initialize ITERATOR to point at the first symbol in DICT whose
SYMBOL_SEARCH_NAME is NAME, as tested using COMPARE (which must use
the same conventions as strcmp_iw and be compatible with any
dictionary hashing function), and return that first symbol, or NULL
if there are no such symbols. */
extern struct symbol *dict_iter_match_first (const struct dictionary *dict,
const char *name,
int (*compare) (const char*,
const char *),
struct dict_iterator *iterator);
/* Advance ITERATOR to point at the next symbol in DICT whose
SYMBOL_SEARCH_NAME is NAME, as tested using COMPARE (see
dict_iter_match_first), or NULL if there are no more such symbols.
Don't call this if you've previously received NULL from
dict_iterator_match_first or dict_iterator_match_next on this
iteration. And don't call it unless ITERATOR was created by a
previous call to dict_iter_match_first with the same NAME and COMPARE. */
extern struct symbol *dict_iter_match_next (const char *name,
int (*compare) (const char*,
const char *),
struct dict_iterator *iterator);
/* Return some notion of the size of the dictionary: the number of
symbols if we have that, the number of hash buckets otherwise. */
extern int dict_size (const struct dictionary *dict);
/* Macro to loop through all symbols in a dictionary DICT, in no
particular order. ITER is a struct dict_iterator (NOTE: __not__ a
struct dict_iterator *), and SYM points to the current symbol.
It's implemented as a single loop, so you can terminate the loop
early by a break if you desire. */
#define ALL_DICT_SYMBOLS(dict, iter, sym) \
for ((sym) = dict_iterator_first ((dict), &(iter)); \
(sym); \
(sym) = dict_iterator_next (&(iter)))
#endif /* DICTIONARY_H */