1 /* Caching of GDB/DWARF index files.
3 Copyright (C) 1994-2023 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "dwarf2/index-cache.h"
24 #include "cli/cli-cmds.h"
25 #include "cli/cli-decode.h"
27 #include "gdbsupport/scoped_mmap.h"
28 #include "gdbsupport/pathstuff.h"
29 #include "dwarf2/index-write.h"
30 #include "dwarf2/read.h"
31 #include "dwarf2/dwz.h"
33 #include "gdbsupport/selftest.h"
37 /* When set to true, show debug messages about the index cache. */
38 static bool debug_index_cache
= false;
40 #define index_cache_debug(FMT, ...) \
41 debug_prefixed_printf_cond_nofunc (debug_index_cache, "index-cache", \
44 /* The index cache directory, used for "set/show index-cache directory". */
45 static std::string index_cache_directory
;
47 /* See dwarf-index.cache.h. */
48 index_cache global_index_cache
;
50 /* set/show index-cache commands. */
51 static cmd_list_element
*set_index_cache_prefix_list
;
52 static cmd_list_element
*show_index_cache_prefix_list
;
54 /* Default destructor of index_cache_resource. */
55 index_cache_resource::~index_cache_resource () = default;
57 /* See dwarf-index-cache.h. */
60 index_cache::set_directory (std::string dir
)
62 gdb_assert (!dir
.empty ());
64 m_dir
= std::move (dir
);
66 index_cache_debug ("now using directory %s", m_dir
.c_str ());
69 /* See dwarf-index-cache.h. */
72 index_cache::enable ()
74 index_cache_debug ("enabling (%s)", m_dir
.c_str ());
79 /* See dwarf-index-cache.h. */
82 index_cache::disable ()
84 index_cache_debug ("disabling");
89 /* See dwarf-index-cache.h. */
92 index_cache::store (dwarf2_per_bfd
*per_bfd
)
97 /* Get build id of objfile. */
98 const bfd_build_id
*build_id
= build_id_bfd_get (per_bfd
->obfd
);
99 if (build_id
== nullptr)
101 index_cache_debug ("objfile %s has no build id",
102 bfd_get_filename (per_bfd
->obfd
));
106 std::string build_id_str
= build_id_to_string (build_id
);
108 /* Get build id of dwz file, if present. */
109 gdb::optional
<std::string
> dwz_build_id_str
;
110 const dwz_file
*dwz
= dwarf2_get_dwz_file (per_bfd
);
111 const char *dwz_build_id_ptr
= NULL
;
115 const bfd_build_id
*dwz_build_id
= build_id_bfd_get (dwz
->dwz_bfd
.get ());
117 if (dwz_build_id
== nullptr)
119 index_cache_debug ("dwz objfile %s has no build id",
124 dwz_build_id_str
= build_id_to_string (dwz_build_id
);
125 dwz_build_id_ptr
= dwz_build_id_str
->c_str ();
130 warning (_("The index cache directory name is empty, skipping store."));
136 /* Try to create the containing directory. */
137 if (!mkdir_recursive (m_dir
.c_str ()))
139 warning (_("index cache: could not make cache directory: %s"),
140 safe_strerror (errno
));
144 index_cache_debug ("writing index cache for objfile %s",
145 bfd_get_filename (per_bfd
->obfd
));
147 /* Write the index itself to the directory, using the build id as the
149 write_dwarf_index (per_bfd
, m_dir
.c_str (),
150 build_id_str
.c_str (), dwz_build_id_ptr
,
151 dw_index_kind::GDB_INDEX
);
153 catch (const gdb_exception_error
&except
)
155 index_cache_debug ("couldn't store index cache for objfile %s: %s",
156 bfd_get_filename (per_bfd
->obfd
), except
.what ());
162 /* Hold the resources for an mmapped index file. */
164 struct index_cache_resource_mmap final
: public index_cache_resource
166 /* Try to mmap FILENAME. Throw an exception on failure, including if the
167 file doesn't exist. */
168 index_cache_resource_mmap (const char *filename
)
169 : mapping (mmap_file (filename
))
175 /* See dwarf-index-cache.h. */
177 gdb::array_view
<const gdb_byte
>
178 index_cache::lookup_gdb_index (const bfd_build_id
*build_id
,
179 std::unique_ptr
<index_cache_resource
> *resource
)
186 warning (_("The index cache directory name is empty, skipping cache "
191 /* Compute where we would expect a gdb index file for this build id to be. */
192 std::string filename
= make_index_filename (build_id
, INDEX4_SUFFIX
);
196 index_cache_debug ("trying to read %s",
199 /* Try to map that file. */
200 index_cache_resource_mmap
*mmap_resource
201 = new index_cache_resource_mmap (filename
.c_str ());
203 /* Yay, it worked! Hand the resource to the caller. */
204 resource
->reset (mmap_resource
);
206 return gdb::array_view
<const gdb_byte
>
207 ((const gdb_byte
*) mmap_resource
->mapping
.get (),
208 mmap_resource
->mapping
.size ());
210 catch (const gdb_exception_error
&except
)
212 index_cache_debug ("couldn't read %s: %s",
213 filename
.c_str (), except
.what ());
219 #else /* !HAVE_SYS_MMAN_H */
221 /* See dwarf-index-cache.h. This is a no-op on unsupported systems. */
223 gdb::array_view
<const gdb_byte
>
224 index_cache::lookup_gdb_index (const bfd_build_id
*build_id
,
225 std::unique_ptr
<index_cache_resource
> *resource
)
232 /* See dwarf-index-cache.h. */
235 index_cache::make_index_filename (const bfd_build_id
*build_id
,
236 const char *suffix
) const
238 std::string build_id_str
= build_id_to_string (build_id
);
240 return m_dir
+ SLASH_STRING
+ build_id_str
+ suffix
;
243 /* True when we are executing "show index-cache". This is used to improve the
244 printout a little bit. */
245 static bool in_show_index_cache_command
= false;
247 /* "show index-cache" handler. */
250 show_index_cache_command (const char *arg
, int from_tty
)
252 /* Note that we are executing "show index-cache". */
253 auto restore_flag
= make_scoped_restore (&in_show_index_cache_command
, true);
255 /* Call all "show index-cache" subcommands. */
256 cmd_show_list (show_index_cache_prefix_list
, from_tty
);
260 (_("The index cache is currently %s.\n"),
261 global_index_cache
.enabled () ? _("enabled") : _("disabled"));
264 /* "set/show index-cache enabled" set callback. */
267 set_index_cache_enabled_command (bool value
)
270 global_index_cache
.enable ();
272 global_index_cache
.disable ();
275 /* "set/show index-cache enabled" get callback. */
278 get_index_cache_enabled_command ()
280 return global_index_cache
.enabled ();
283 /* "set/show index-cache enabled" show callback. */
286 show_index_cache_enabled_command (ui_file
*stream
, int from_tty
,
287 cmd_list_element
*cmd
, const char *value
)
289 gdb_printf (stream
, _("The index cache is %s.\n"), value
);
292 /* "set index-cache directory" handler. */
295 set_index_cache_directory_command (const char *arg
, int from_tty
,
296 cmd_list_element
*element
)
298 /* Make sure the index cache directory is absolute and tilde-expanded. */
299 index_cache_directory
= gdb_abspath (index_cache_directory
.c_str ());
300 global_index_cache
.set_directory (index_cache_directory
);
303 /* "show index-cache stats" handler. */
306 show_index_cache_stats_command (const char *arg
, int from_tty
)
308 const char *indent
= "";
310 /* If this command is invoked through "show index-cache", make the display a
312 if (in_show_index_cache_command
)
318 gdb_printf (_("%s Cache hits (this session): %u\n"),
319 indent
, global_index_cache
.n_hits ());
320 gdb_printf (_("%sCache misses (this session): %u\n"),
321 indent
, global_index_cache
.n_misses ());
324 void _initialize_index_cache ();
326 _initialize_index_cache ()
328 /* Set the default index cache directory. */
329 std::string cache_dir
= get_standard_cache_dir ();
330 if (!cache_dir
.empty ())
332 index_cache_directory
= cache_dir
;
333 global_index_cache
.set_directory (std::move (cache_dir
));
336 warning (_("Couldn't determine a path for the index cache directory."));
338 /* set index-cache */
339 add_basic_prefix_cmd ("index-cache", class_files
,
340 _("Set index-cache options."),
341 &set_index_cache_prefix_list
,
344 /* show index-cache */
345 add_prefix_cmd ("index-cache", class_files
, show_index_cache_command
,
346 _("Show index-cache options."), &show_index_cache_prefix_list
,
349 /* set/show index-cache enabled */
350 set_show_commands setshow_index_cache_enabled_cmds
351 = add_setshow_boolean_cmd ("enabled", class_files
,
352 _("Enable the index cache."),
353 _("Show whether the index cache is enabled."),
354 _("When on, enable the use of the index cache."),
355 set_index_cache_enabled_command
,
356 get_index_cache_enabled_command
,
357 show_index_cache_enabled_command
,
358 &set_index_cache_prefix_list
,
359 &show_index_cache_prefix_list
);
361 /* set index-cache on */
362 cmd_list_element
*set_index_cache_on_cmd
363 = add_alias_cmd ("on", setshow_index_cache_enabled_cmds
.set
, class_files
,
364 false, &set_index_cache_prefix_list
);
365 deprecate_cmd (set_index_cache_on_cmd
, "set index-cache enabled on");
366 set_index_cache_on_cmd
->default_args
= "on";
368 /* set index-cache off */
369 cmd_list_element
*set_index_cache_off_cmd
370 = add_alias_cmd ("off", setshow_index_cache_enabled_cmds
.set
, class_files
,
371 false, &set_index_cache_prefix_list
);
372 deprecate_cmd (set_index_cache_off_cmd
, "set index-cache enabled off");
373 set_index_cache_off_cmd
->default_args
= "off";
375 /* set index-cache directory */
376 add_setshow_filename_cmd ("directory", class_files
, &index_cache_directory
,
377 _("Set the directory of the index cache."),
378 _("Show the directory of the index cache."),
380 set_index_cache_directory_command
, NULL
,
381 &set_index_cache_prefix_list
,
382 &show_index_cache_prefix_list
);
384 /* show index-cache stats */
385 add_cmd ("stats", class_files
, show_index_cache_stats_command
,
386 _("Show some stats about the index cache."),
387 &show_index_cache_prefix_list
);
389 /* set debug index-cache */
390 add_setshow_boolean_cmd ("index-cache", class_maintenance
,
392 _("Set display of index-cache debug messages."),
393 _("Show display of index-cache debug messages."),
395 When non-zero, debugging output for the index cache is displayed."),
397 &setdebuglist
, &showdebuglist
);