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87d6a7aa SM |
1 | /* Caching of GDB/DWARF index files. |
2 | ||
b811d2c2 | 3 | Copyright (C) 1994-2020 Free Software Foundation, Inc. |
87d6a7aa SM |
4 | |
5 | This file is part of GDB. | |
6 | ||
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. | |
11 | ||
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. | |
16 | ||
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/>. */ | |
19 | ||
20 | #include "defs.h" | |
82ca8957 | 21 | #include "dwarf2/index-cache.h" |
87d6a7aa SM |
22 | |
23 | #include "build-id.h" | |
24 | #include "cli/cli-cmds.h" | |
25 | #include "command.h" | |
268a13a5 TT |
26 | #include "gdbsupport/scoped_mmap.h" |
27 | #include "gdbsupport/pathstuff.h" | |
82ca8957 TT |
28 | #include "dwarf2/index-write.h" |
29 | #include "dwarf2/read.h" | |
9fda78b6 | 30 | #include "dwarf2/dwz.h" |
87d6a7aa | 31 | #include "objfiles.h" |
268a13a5 | 32 | #include "gdbsupport/selftest.h" |
4de283e4 TT |
33 | #include <string> |
34 | #include <stdlib.h> | |
87d6a7aa | 35 | |
491144b5 CB |
36 | /* When set to true, show debug messages about the index cache. */ |
37 | static bool debug_index_cache = false; | |
87d6a7aa SM |
38 | |
39 | /* The index cache directory, used for "set/show index-cache directory". */ | |
40 | static char *index_cache_directory = NULL; | |
41 | ||
42 | /* See dwarf-index.cache.h. */ | |
43 | index_cache global_index_cache; | |
44 | ||
45 | /* set/show index-cache commands. */ | |
46 | static cmd_list_element *set_index_cache_prefix_list; | |
47 | static cmd_list_element *show_index_cache_prefix_list; | |
48 | ||
87d6a7aa SM |
49 | /* Default destructor of index_cache_resource. */ |
50 | index_cache_resource::~index_cache_resource () = default; | |
51 | ||
52 | /* See dwarf-index-cache.h. */ | |
53 | ||
54 | void | |
55 | index_cache::set_directory (std::string dir) | |
56 | { | |
57 | gdb_assert (!dir.empty ()); | |
58 | ||
59 | m_dir = std::move (dir); | |
60 | ||
61 | if (debug_index_cache) | |
62 | printf_unfiltered ("index cache: now using directory %s\n", m_dir.c_str ()); | |
63 | } | |
64 | ||
65 | /* See dwarf-index-cache.h. */ | |
66 | ||
67 | void | |
68 | index_cache::enable () | |
69 | { | |
70 | if (debug_index_cache) | |
71 | printf_unfiltered ("index cache: enabling (%s)\n", m_dir.c_str ()); | |
72 | ||
73 | m_enabled = true; | |
74 | } | |
75 | ||
76 | /* See dwarf-index-cache.h. */ | |
77 | ||
78 | void | |
79 | index_cache::disable () | |
80 | { | |
81 | if (debug_index_cache) | |
82 | printf_unfiltered ("index cache: disabling\n"); | |
83 | ||
84 | m_enabled = false; | |
85 | } | |
86 | ||
87 | /* See dwarf-index-cache.h. */ | |
88 | ||
89 | void | |
90 | index_cache::store (struct dwarf2_per_objfile *dwarf2_per_objfile) | |
91 | { | |
92 | objfile *obj = dwarf2_per_objfile->objfile; | |
93 | ||
94 | if (!enabled ()) | |
95 | return; | |
96 | ||
c4973306 | 97 | /* Get build id of objfile. */ |
87d6a7aa SM |
98 | const bfd_build_id *build_id = build_id_bfd_get (obj->obfd); |
99 | if (build_id == nullptr) | |
100 | { | |
101 | if (debug_index_cache) | |
102 | printf_unfiltered ("index cache: objfile %s has no build id\n", | |
103 | objfile_name (obj)); | |
104 | return; | |
105 | } | |
106 | ||
c4973306 SM |
107 | std::string build_id_str = build_id_to_string (build_id); |
108 | ||
109 | /* Get build id of dwz file, if present. */ | |
110 | gdb::optional<std::string> dwz_build_id_str; | |
c3699833 | 111 | const dwz_file *dwz = dwarf2_get_dwz_file (dwarf2_per_objfile->per_bfd); |
c4973306 SM |
112 | const char *dwz_build_id_ptr = NULL; |
113 | ||
114 | if (dwz != nullptr) | |
115 | { | |
116 | const bfd_build_id *dwz_build_id = build_id_bfd_get (dwz->dwz_bfd.get ()); | |
117 | ||
118 | if (dwz_build_id == nullptr) | |
119 | { | |
120 | if (debug_index_cache) | |
121 | printf_unfiltered ("index cache: dwz objfile %s has no build id\n", | |
122 | dwz->filename ()); | |
123 | return; | |
124 | } | |
125 | ||
126 | dwz_build_id_str = build_id_to_string (dwz_build_id); | |
127 | dwz_build_id_ptr = dwz_build_id_str->c_str (); | |
128 | } | |
129 | ||
87d6a7aa SM |
130 | if (m_dir.empty ()) |
131 | { | |
132 | warning (_("The index cache directory name is empty, skipping store.")); | |
133 | return; | |
134 | } | |
135 | ||
a70b8144 | 136 | try |
87d6a7aa SM |
137 | { |
138 | /* Try to create the containing directory. */ | |
e418a61a TT |
139 | if (!mkdir_recursive (m_dir.c_str ())) |
140 | { | |
422186a9 | 141 | warning (_("index cache: could not make cache directory: %s"), |
e418a61a TT |
142 | safe_strerror (errno)); |
143 | return; | |
144 | } | |
87d6a7aa SM |
145 | |
146 | if (debug_index_cache) | |
147 | printf_unfiltered ("index cache: writing index cache for objfile %s\n", | |
c4973306 | 148 | objfile_name (obj)); |
87d6a7aa SM |
149 | |
150 | /* Write the index itself to the directory, using the build id as the | |
151 | filename. */ | |
152 | write_psymtabs_to_index (dwarf2_per_objfile, m_dir.c_str (), | |
c4973306 SM |
153 | build_id_str.c_str (), dwz_build_id_ptr, |
154 | dw_index_kind::GDB_INDEX); | |
87d6a7aa | 155 | } |
230d2906 | 156 | catch (const gdb_exception_error &except) |
87d6a7aa SM |
157 | { |
158 | if (debug_index_cache) | |
159 | printf_unfiltered ("index cache: couldn't store index cache for objfile " | |
3d6e9d23 | 160 | "%s: %s", objfile_name (obj), except.what ()); |
87d6a7aa | 161 | } |
87d6a7aa SM |
162 | } |
163 | ||
164 | #if HAVE_SYS_MMAN_H | |
165 | ||
166 | /* Hold the resources for an mmapped index file. */ | |
167 | ||
168 | struct index_cache_resource_mmap final : public index_cache_resource | |
169 | { | |
170 | /* Try to mmap FILENAME. Throw an exception on failure, including if the | |
171 | file doesn't exist. */ | |
172 | index_cache_resource_mmap (const char *filename) | |
173 | : mapping (mmap_file (filename)) | |
174 | {} | |
175 | ||
176 | scoped_mmap mapping; | |
177 | }; | |
178 | ||
179 | /* See dwarf-index-cache.h. */ | |
180 | ||
181 | gdb::array_view<const gdb_byte> | |
182 | index_cache::lookup_gdb_index (const bfd_build_id *build_id, | |
183 | std::unique_ptr<index_cache_resource> *resource) | |
184 | { | |
185 | if (!enabled ()) | |
186 | return {}; | |
187 | ||
188 | if (m_dir.empty ()) | |
189 | { | |
190 | warning (_("The index cache directory name is empty, skipping cache " | |
191 | "lookup.")); | |
192 | return {}; | |
193 | } | |
194 | ||
195 | /* Compute where we would expect a gdb index file for this build id to be. */ | |
196 | std::string filename = make_index_filename (build_id, INDEX4_SUFFIX); | |
197 | ||
a70b8144 | 198 | try |
87d6a7aa SM |
199 | { |
200 | if (debug_index_cache) | |
201 | printf_unfiltered ("index cache: trying to read %s\n", | |
202 | filename.c_str ()); | |
203 | ||
204 | /* Try to map that file. */ | |
205 | index_cache_resource_mmap *mmap_resource | |
206 | = new index_cache_resource_mmap (filename.c_str ()); | |
207 | ||
208 | /* Yay, it worked! Hand the resource to the caller. */ | |
209 | resource->reset (mmap_resource); | |
210 | ||
211 | return gdb::array_view<const gdb_byte> | |
212 | ((const gdb_byte *) mmap_resource->mapping.get (), | |
213 | mmap_resource->mapping.size ()); | |
214 | } | |
230d2906 | 215 | catch (const gdb_exception_error &except) |
87d6a7aa SM |
216 | { |
217 | if (debug_index_cache) | |
218 | printf_unfiltered ("index cache: couldn't read %s: %s\n", | |
3d6e9d23 | 219 | filename.c_str (), except.what ()); |
87d6a7aa | 220 | } |
87d6a7aa SM |
221 | |
222 | return {}; | |
223 | } | |
224 | ||
225 | #else /* !HAVE_SYS_MMAN_H */ | |
226 | ||
227 | /* See dwarf-index-cache.h. This is a no-op on unsupported systems. */ | |
228 | ||
229 | gdb::array_view<const gdb_byte> | |
230 | index_cache::lookup_gdb_index (const bfd_build_id *build_id, | |
231 | std::unique_ptr<index_cache_resource> *resource) | |
232 | { | |
233 | return {}; | |
234 | } | |
235 | ||
236 | #endif | |
237 | ||
238 | /* See dwarf-index-cache.h. */ | |
239 | ||
240 | std::string | |
241 | index_cache::make_index_filename (const bfd_build_id *build_id, | |
242 | const char *suffix) const | |
243 | { | |
244 | std::string build_id_str = build_id_to_string (build_id); | |
245 | ||
246 | return m_dir + SLASH_STRING + build_id_str + suffix; | |
247 | } | |
248 | ||
87d6a7aa SM |
249 | /* True when we are executing "show index-cache". This is used to improve the |
250 | printout a little bit. */ | |
251 | static bool in_show_index_cache_command = false; | |
252 | ||
253 | /* "show index-cache" handler. */ | |
254 | ||
255 | static void | |
256 | show_index_cache_command (const char *arg, int from_tty) | |
257 | { | |
258 | /* Note that we are executing "show index-cache". */ | |
259 | auto restore_flag = make_scoped_restore (&in_show_index_cache_command, true); | |
260 | ||
261 | /* Call all "show index-cache" subcommands. */ | |
7aa1b46f | 262 | cmd_show_list (show_index_cache_prefix_list, from_tty); |
87d6a7aa SM |
263 | |
264 | printf_unfiltered ("\n"); | |
265 | printf_unfiltered | |
266 | (_("The index cache is currently %s.\n"), | |
267 | global_index_cache.enabled () ? _("enabled") : _("disabled")); | |
268 | } | |
269 | ||
270 | /* "set index-cache on" handler. */ | |
271 | ||
272 | static void | |
273 | set_index_cache_on_command (const char *arg, int from_tty) | |
274 | { | |
275 | global_index_cache.enable (); | |
276 | } | |
277 | ||
278 | /* "set index-cache off" handler. */ | |
279 | ||
280 | static void | |
281 | set_index_cache_off_command (const char *arg, int from_tty) | |
282 | { | |
283 | global_index_cache.disable (); | |
284 | } | |
285 | ||
286 | /* "set index-cache directory" handler. */ | |
287 | ||
288 | static void | |
289 | set_index_cache_directory_command (const char *arg, int from_tty, | |
290 | cmd_list_element *element) | |
291 | { | |
292 | /* Make sure the index cache directory is absolute and tilde-expanded. */ | |
293 | gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (index_cache_directory)); | |
294 | xfree (index_cache_directory); | |
295 | index_cache_directory = abs.release (); | |
296 | global_index_cache.set_directory (index_cache_directory); | |
297 | } | |
298 | ||
299 | /* "show index-cache stats" handler. */ | |
300 | ||
301 | static void | |
302 | show_index_cache_stats_command (const char *arg, int from_tty) | |
303 | { | |
304 | const char *indent = ""; | |
305 | ||
306 | /* If this command is invoked through "show index-cache", make the display a | |
307 | bit nicer. */ | |
308 | if (in_show_index_cache_command) | |
309 | { | |
310 | indent = " "; | |
311 | printf_unfiltered ("\n"); | |
312 | } | |
313 | ||
314 | printf_unfiltered (_("%s Cache hits (this session): %u\n"), | |
315 | indent, global_index_cache.n_hits ()); | |
316 | printf_unfiltered (_("%sCache misses (this session): %u\n"), | |
317 | indent, global_index_cache.n_misses ()); | |
318 | } | |
319 | ||
6c265988 | 320 | void _initialize_index_cache (); |
87d6a7aa SM |
321 | void |
322 | _initialize_index_cache () | |
323 | { | |
324 | /* Set the default index cache directory. */ | |
325 | std::string cache_dir = get_standard_cache_dir (); | |
326 | if (!cache_dir.empty ()) | |
327 | { | |
328 | index_cache_directory = xstrdup (cache_dir.c_str ()); | |
329 | global_index_cache.set_directory (std::move (cache_dir)); | |
330 | } | |
331 | else | |
332 | warning (_("Couldn't determine a path for the index cache directory.")); | |
333 | ||
334 | /* set index-cache */ | |
3b6acaee TT |
335 | add_basic_prefix_cmd ("index-cache", class_files, |
336 | _("Set index-cache options."), | |
337 | &set_index_cache_prefix_list, | |
338 | "set index-cache ", false, &setlist); | |
87d6a7aa SM |
339 | |
340 | /* show index-cache */ | |
341 | add_prefix_cmd ("index-cache", class_files, show_index_cache_command, | |
590042fc | 342 | _("Show index-cache options."), &show_index_cache_prefix_list, |
87d6a7aa SM |
343 | "show index-cache ", false, &showlist); |
344 | ||
345 | /* set index-cache on */ | |
346 | add_cmd ("on", class_files, set_index_cache_on_command, | |
347 | _("Enable the index cache."), &set_index_cache_prefix_list); | |
348 | ||
349 | /* set index-cache off */ | |
350 | add_cmd ("off", class_files, set_index_cache_off_command, | |
351 | _("Disable the index cache."), &set_index_cache_prefix_list); | |
352 | ||
353 | /* set index-cache directory */ | |
354 | add_setshow_filename_cmd ("directory", class_files, &index_cache_directory, | |
355 | _("Set the directory of the index cache."), | |
356 | _("Show the directory of the index cache."), | |
357 | NULL, | |
358 | set_index_cache_directory_command, NULL, | |
359 | &set_index_cache_prefix_list, | |
360 | &show_index_cache_prefix_list); | |
361 | ||
362 | /* show index-cache stats */ | |
363 | add_cmd ("stats", class_files, show_index_cache_stats_command, | |
364 | _("Show some stats about the index cache."), | |
365 | &show_index_cache_prefix_list); | |
366 | ||
367 | /* set debug index-cache */ | |
368 | add_setshow_boolean_cmd ("index-cache", class_maintenance, | |
369 | &debug_index_cache, | |
370 | _("Set display of index-cache debug messages."), | |
371 | _("Show display of index-cache debug messages."), | |
372 | _("\ | |
373 | When non-zero, debugging output for the index cache is displayed."), | |
374 | NULL, NULL, | |
375 | &setdebuglist, &showdebuglist); | |
87d6a7aa | 376 | } |