1 /* Caching of GDB/DWARF index files.
3 Copyright (C) 1994-2019 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 "dwarf-index-cache.h"
24 #include "cli/cli-cmds.h"
26 #include "common/scoped_mmap.h"
27 #include "common/pathstuff.h"
28 #include "dwarf-index-write.h"
29 #include "dwarf2read.h"
31 #include "common/selftest.h"
35 /* When set to 1, show debug messages about the index cache. */
36 static int debug_index_cache = 0;
38 /* The index cache directory, used for "set/show index-cache directory". */
39 static char *index_cache_directory = NULL;
41 /* See dwarf-index.cache.h. */
42 index_cache global_index_cache;
44 /* set/show index-cache commands. */
45 static cmd_list_element *set_index_cache_prefix_list;
46 static cmd_list_element *show_index_cache_prefix_list;
48 /* Default destructor of index_cache_resource. */
49 index_cache_resource::~index_cache_resource () = default;
51 /* See dwarf-index-cache.h. */
54 index_cache::set_directory (std::string dir)
56 gdb_assert (!dir.empty ());
58 m_dir = std::move (dir);
60 if (debug_index_cache)
61 printf_unfiltered ("index cache: now using directory %s\n", m_dir.c_str ());
64 /* See dwarf-index-cache.h. */
67 index_cache::enable ()
69 if (debug_index_cache)
70 printf_unfiltered ("index cache: enabling (%s)\n", m_dir.c_str ());
75 /* See dwarf-index-cache.h. */
78 index_cache::disable ()
80 if (debug_index_cache)
81 printf_unfiltered ("index cache: disabling\n");
86 /* See dwarf-index-cache.h. */
89 index_cache::store (struct dwarf2_per_objfile *dwarf2_per_objfile)
91 objfile *obj = dwarf2_per_objfile->objfile;
96 /* Get build id of objfile. */
97 const bfd_build_id *build_id = build_id_bfd_get (obj->obfd);
98 if (build_id == nullptr)
100 if (debug_index_cache)
101 printf_unfiltered ("index cache: objfile %s has no build id\n",
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 (dwarf2_per_objfile);
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 if (debug_index_cache)
120 printf_unfiltered ("index cache: dwz objfile %s has no build id\n",
125 dwz_build_id_str = build_id_to_string (dwz_build_id);
126 dwz_build_id_ptr = dwz_build_id_str->c_str ();
131 warning (_("The index cache directory name is empty, skipping store."));
137 /* Try to create the containing directory. */
138 if (!mkdir_recursive (m_dir.c_str ()))
140 warning (_("index cache: could not make cache directory: %s"),
141 safe_strerror (errno));
145 if (debug_index_cache)
146 printf_unfiltered ("index cache: writing index cache for objfile %s\n",
149 /* Write the index itself to the directory, using the build id as the
151 write_psymtabs_to_index (dwarf2_per_objfile, m_dir.c_str (),
152 build_id_str.c_str (), dwz_build_id_ptr,
153 dw_index_kind::GDB_INDEX);
155 catch (const gdb_exception_error &except)
157 if (debug_index_cache)
158 printf_unfiltered ("index cache: couldn't store index cache for objfile "
159 "%s: %s", objfile_name (obj), except.what ());
165 /* Hold the resources for an mmapped index file. */
167 struct index_cache_resource_mmap final : public index_cache_resource
169 /* Try to mmap FILENAME. Throw an exception on failure, including if the
170 file doesn't exist. */
171 index_cache_resource_mmap (const char *filename)
172 : mapping (mmap_file (filename))
178 /* See dwarf-index-cache.h. */
180 gdb::array_view<const gdb_byte>
181 index_cache::lookup_gdb_index (const bfd_build_id *build_id,
182 std::unique_ptr<index_cache_resource> *resource)
189 warning (_("The index cache directory name is empty, skipping cache "
194 /* Compute where we would expect a gdb index file for this build id to be. */
195 std::string filename = make_index_filename (build_id, INDEX4_SUFFIX);
199 if (debug_index_cache)
200 printf_unfiltered ("index cache: trying to read %s\n",
203 /* Try to map that file. */
204 index_cache_resource_mmap *mmap_resource
205 = new index_cache_resource_mmap (filename.c_str ());
207 /* Yay, it worked! Hand the resource to the caller. */
208 resource->reset (mmap_resource);
210 return gdb::array_view<const gdb_byte>
211 ((const gdb_byte *) mmap_resource->mapping.get (),
212 mmap_resource->mapping.size ());
214 catch (const gdb_exception_error &except)
216 if (debug_index_cache)
217 printf_unfiltered ("index cache: couldn't read %s: %s\n",
218 filename.c_str (), except.what ());
224 #else /* !HAVE_SYS_MMAN_H */
226 /* See dwarf-index-cache.h. This is a no-op on unsupported systems. */
228 gdb::array_view<const gdb_byte>
229 index_cache::lookup_gdb_index (const bfd_build_id *build_id,
230 std::unique_ptr<index_cache_resource> *resource)
237 /* See dwarf-index-cache.h. */
240 index_cache::make_index_filename (const bfd_build_id *build_id,
241 const char *suffix) const
243 std::string build_id_str = build_id_to_string (build_id);
245 return m_dir + SLASH_STRING + build_id_str + suffix;
248 /* "set index-cache" handler. */
251 set_index_cache_command (const char *arg, int from_tty)
253 printf_unfiltered (_("\
254 Missing arguments. See \"help set index-cache\" for help.\n"));
257 /* True when we are executing "show index-cache". This is used to improve the
258 printout a little bit. */
259 static bool in_show_index_cache_command = false;
261 /* "show index-cache" handler. */
264 show_index_cache_command (const char *arg, int from_tty)
266 /* Note that we are executing "show index-cache". */
267 auto restore_flag = make_scoped_restore (&in_show_index_cache_command, true);
269 /* Call all "show index-cache" subcommands. */
270 cmd_show_list (show_index_cache_prefix_list, from_tty, "");
272 printf_unfiltered ("\n");
274 (_("The index cache is currently %s.\n"),
275 global_index_cache.enabled () ? _("enabled") : _("disabled"));
278 /* "set index-cache on" handler. */
281 set_index_cache_on_command (const char *arg, int from_tty)
283 global_index_cache.enable ();
286 /* "set index-cache off" handler. */
289 set_index_cache_off_command (const char *arg, int from_tty)
291 global_index_cache.disable ();
294 /* "set index-cache directory" handler. */
297 set_index_cache_directory_command (const char *arg, int from_tty,
298 cmd_list_element *element)
300 /* Make sure the index cache directory is absolute and tilde-expanded. */
301 gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (index_cache_directory));
302 xfree (index_cache_directory);
303 index_cache_directory = abs.release ();
304 global_index_cache.set_directory (index_cache_directory);
307 /* "show index-cache stats" handler. */
310 show_index_cache_stats_command (const char *arg, int from_tty)
312 const char *indent = "";
314 /* If this command is invoked through "show index-cache", make the display a
316 if (in_show_index_cache_command)
319 printf_unfiltered ("\n");
322 printf_unfiltered (_("%s Cache hits (this session): %u\n"),
323 indent, global_index_cache.n_hits ());
324 printf_unfiltered (_("%sCache misses (this session): %u\n"),
325 indent, global_index_cache.n_misses ());
329 _initialize_index_cache ()
331 /* Set the default index cache directory. */
332 std::string cache_dir = get_standard_cache_dir ();
333 if (!cache_dir.empty ())
335 index_cache_directory = xstrdup (cache_dir.c_str ());
336 global_index_cache.set_directory (std::move (cache_dir));
339 warning (_("Couldn't determine a path for the index cache directory."));
341 /* set index-cache */
342 add_prefix_cmd ("index-cache", class_files, set_index_cache_command,
343 _("Set index-cache options"), &set_index_cache_prefix_list,
344 "set index-cache ", false, &setlist);
346 /* show index-cache */
347 add_prefix_cmd ("index-cache", class_files, show_index_cache_command,
348 _("Show index-cache options"), &show_index_cache_prefix_list,
349 "show index-cache ", false, &showlist);
351 /* set index-cache on */
352 add_cmd ("on", class_files, set_index_cache_on_command,
353 _("Enable the index cache."), &set_index_cache_prefix_list);
355 /* set index-cache off */
356 add_cmd ("off", class_files, set_index_cache_off_command,
357 _("Disable the index cache."), &set_index_cache_prefix_list);
359 /* set index-cache directory */
360 add_setshow_filename_cmd ("directory", class_files, &index_cache_directory,
361 _("Set the directory of the index cache."),
362 _("Show the directory of the index cache."),
364 set_index_cache_directory_command, NULL,
365 &set_index_cache_prefix_list,
366 &show_index_cache_prefix_list);
368 /* show index-cache stats */
369 add_cmd ("stats", class_files, show_index_cache_stats_command,
370 _("Show some stats about the index cache."),
371 &show_index_cache_prefix_list);
373 /* set debug index-cache */
374 add_setshow_boolean_cmd ("index-cache", class_maintenance,
376 _("Set display of index-cache debug messages."),
377 _("Show display of index-cache debug messages."),
379 When non-zero, debugging output for the index cache is displayed."),
381 &setdebuglist, &showdebuglist);