binutils-gdb/gdb/quick-symbol.h
Tom de Vries 00105aa1c4 [gdb/symtab] Don't expand non-Ada CUs for info exceptions
I noticed when running test-case gdb.ada/info_exc.exp with glibc debug info
installed, that the "info exceptions" command that lists all Ada exceptions
also expands non-Ada CUs, which includes CUs in
/lib64/ld-linux-x86-64.so.2 and /lib64/libc.so.6.

Fix this by:
- adding a new lang_matcher parameter to the expand_symtabs_matching
  function, and
- using that new parameter in the expand_symtabs_matching call in
  ada_add_global_exceptions.

The new parameter is a hint, meaning implementations are free to ignore it and
expand CUs with any language.  This is the case for partial symtabs, I'm not
sure whether it makes sense to implement support for this there.

Conversely, when processing a CU with language C and name "<artificial>"
(as produced by GCC LTO), the CU may not really have a single language and we
should ignore the lang_matcher.  See also commit d2f6771173
("Fix 'catch exception' with -flto").

Now that we have lang_matcher available, also use it to limit name splitting
styles and symbol matchers to those applicable to the matched languages.

Without this patch we have (with a gdb build with -O0):
...
$ time gdb -q -batch -x outputs/gdb.ada/info_exc/gdb.in.1 > /dev/null
real	0m1.866s
user	0m2.089s
sys	0m0.120s
...
and with this patch we have:
...
$ time gdb -q -batch -x outputs/gdb.ada/info_exc/gdb.in.1 > /dev/null
real	0m0.469s
user	0m0.777s
sys	0m0.051s
...

Or, to put it in terms of number of CUs, we have 1853 CUs:
...
$ gdb -q -batch -readnow outputs/gdb.ada/info_exc/foo \
    -ex start \
    -ex "maint info symtabs" \
    | grep -c " name "
1853
...

Without this patch, we have:
...
$ gdb -q -batch outputs/gdb.ada/info_exc/foo \
    -ex start \
    -ex "info exceptions" \
    -ex "maint info symtabs" \
    | grep -c " name "
1393
...
so ~75% of the CUs is expanded, and with this patch we have:
...
$ gdb <same-as-above>
20
...
so ~1% of the CUs is expanded.

Tested on x86_64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

PR symtab/32182
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32182
2024-09-24 10:24:22 +02:00

210 lines
8.4 KiB
C++

/* "Quick" symbol functions
Copyright (C) 2021-2024 Free Software Foundation, 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 GDB_QUICK_SYMBOL_H
#define GDB_QUICK_SYMBOL_H
/* Like block_enum, but used as flags to pass to lookup functions. */
enum block_search_flag_values
{
SEARCH_GLOBAL_BLOCK = 1,
SEARCH_STATIC_BLOCK = 2
};
DEF_ENUM_FLAGS_TYPE (enum block_search_flag_values, block_search_flags);
/* Callback for quick_symbol_functions->map_symbol_filenames. */
typedef void (symbol_filename_ftype) (const char *filename,
const char *fullname);
/* Callback for quick_symbol_functions->expand_symtabs_matching
to match a file name. */
typedef bool (expand_symtabs_file_matcher_ftype) (const char *filename,
bool basenames);
/* Callback for quick_symbol_functions->expand_symtabs_matching
to match a symbol name. */
typedef bool (expand_symtabs_symbol_matcher_ftype) (const char *name);
/* Callback for quick_symbol_functions->expand_symtabs_matching
to match a language. */
typedef bool (expand_symtabs_lang_matcher_ftype) (enum language lang);
/* Callback for quick_symbol_functions->expand_symtabs_matching
to be called after a symtab has been expanded. If this returns
true, more symtabs are checked; if it returns false, iteration
stops. */
typedef bool (expand_symtabs_exp_notify_ftype) (compunit_symtab *symtab);
/* The "quick" symbol functions exist so that symbol readers can
avoiding an initial read of all the symbols. For example, symbol
readers might choose to use the "partial symbol table" utilities,
which is one implementation of the quick symbol functions.
The quick symbol functions are generally opaque: the underlying
representation is hidden from the caller.
In general, these functions should only look at whatever special
index the symbol reader creates -- looking through the symbol
tables themselves is handled by generic code. If a function is
defined as returning a "symbol table", this means that the function
should only return a newly-created symbol table; it should not
examine pre-existing ones.
The exact list of functions here was determined in an ad hoc way
based on gdb's history. */
struct quick_symbol_functions
{
virtual ~quick_symbol_functions ()
{
}
/* Return true if this objfile has any "partial" symbols
available. */
virtual bool has_symbols (struct objfile *objfile) = 0;
/* Return true if OBJFILE has any unexpanded symtabs. A return value of
false indicates there are no unexpanded symtabs, this might mean that
all of the symtabs have been expanded (full debug has been read in),
or it might been that OBJFILE has no debug information. */
virtual bool has_unexpanded_symtabs (struct objfile *objfile) = 0;
/* Return the symbol table for the "last" file appearing in
OBJFILE. */
virtual struct symtab *find_last_source_symtab (struct objfile *objfile) = 0;
/* Forget all cached full file names for OBJFILE. */
virtual void forget_cached_source_info (struct objfile *objfile) = 0;
/* Check to see if the global symbol is defined in a "partial" symbol table
of OBJFILE. NAME is the name of the symbol to look for. DOMAIN
indicates what sorts of symbols to search for.
If found, sets *symbol_found_p to true and returns the symbol language.
defined, or NULL if no such symbol table exists. */
virtual enum language lookup_global_symbol_language
(struct objfile *objfile,
const char *name,
domain_search_flags domain,
bool *symbol_found_p) = 0;
/* Print statistics about any indices loaded for OBJFILE. The
statistics should be printed to gdb_stdout. This is used for
"maint print statistics". Statistics are printed in two
sections. PRINT_BCACHE is false when printing the first section
of general statistics, and true when printing bcache statistics. */
virtual void print_stats (struct objfile *objfile, bool print_bcache) = 0;
/* Dump any indices loaded for OBJFILE. The dump should go to
gdb_stdout. This is used for "maint print objfiles". */
virtual void dump (struct objfile *objfile) = 0;
/* Read all symbol tables associated with OBJFILE. */
virtual void expand_all_symtabs (struct objfile *objfile) = 0;
/* Expand all symbol tables in OBJFILE matching some criteria.
If LANG_MATCHER returns false, expansion of the symbol table may be
skipped. It may also not be skipped, which the caller needs to take into
account.
FILE_MATCHER is called for each file in OBJFILE. The file name
is passed to it. If the matcher returns false, the file is
skipped. If FILE_MATCHER is NULL the file is not skipped. If
BASENAMES is true the matcher should consider only file base
names (the passed file name is already only the lbasename'd
part).
If the file is not skipped, and SYMBOL_MATCHER and LOOKUP_NAME are NULL,
the symbol table is expanded.
Otherwise, individual symbols are considered.
If DOMAIN does not match, the symbol is skipped.
If the symbol name does not match LOOKUP_NAME, the symbol is skipped.
If SYMBOL_MATCHER returns false, then the symbol is skipped.
Note that if SYMBOL_MATCHER is non-NULL, then LOOKUP_NAME must
also be provided.
Otherwise, the symbol's symbol table is expanded and the
notification function is called. If the notification function
returns false, execution stops and this method returns false.
Otherwise, more files are considered. This method will return
true if all calls to the notification function return true. */
virtual bool expand_symtabs_matching
(struct objfile *objfile,
gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher,
const lookup_name_info *lookup_name,
gdb::function_view<expand_symtabs_symbol_matcher_ftype> symbol_matcher,
gdb::function_view<expand_symtabs_exp_notify_ftype> expansion_notify,
block_search_flags search_flags,
domain_search_flags domain,
gdb::function_view<expand_symtabs_lang_matcher_ftype> lang_matcher
= nullptr) = 0;
/* Return the comp unit from OBJFILE that contains PC and
SECTION. Return NULL if there is no such compunit. This
should return the compunit that contains a symbol whose
address exactly matches PC, or, if there is no exact match, the
compunit that contains a symbol whose address is closest to
PC. */
virtual struct compunit_symtab *find_pc_sect_compunit_symtab
(struct objfile *objfile, bound_minimal_symbol msymbol, CORE_ADDR pc,
struct obj_section *section, int warn_if_readin) = 0;
/* Return the comp unit from OBJFILE that contains a symbol at
ADDRESS. Return NULL if there is no such comp unit. Unlike
find_pc_sect_compunit_symtab, any sort of symbol (not just text
symbols) can be considered, and only exact address matches are
considered. */
virtual struct compunit_symtab *find_compunit_symtab_by_address
(struct objfile *objfile, CORE_ADDR address) = 0;
/* Call a callback for every file defined in OBJFILE whose symtab is
not already read in. FUN is the callback. It is passed the
file's FILENAME and the file's FULLNAME (if need_fullname is
non-zero). */
virtual void map_symbol_filenames
(struct objfile *objfile,
gdb::function_view<symbol_filename_ftype> fun,
bool need_fullname) = 0;
/* Compute the name and language of the main function for the given
objfile. Normally this is done during symbol reading, but this
method exists in case this work is done in a worker thread and
must be waited for. The implementation can call
set_objfile_main_name if results are found. */
virtual void compute_main_name (struct objfile *objfile)
{
}
};
typedef std::unique_ptr<quick_symbol_functions> quick_symbol_functions_up;
#endif /* GDB_QUICK_SYMBOL_H */