blob: f439b37db5aede62750c81fc98d55bcdbb5af495 [file] [log] [blame]
/* Caching of GDB/DWARF index files.
Copyright (C) 1994-2021 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/>. */
#include "defs.h"
#include "dwarf2/index-cache.h"
#include "build-id.h"
#include "cli/cli-cmds.h"
#include "command.h"
#include "gdbsupport/scoped_mmap.h"
#include "gdbsupport/pathstuff.h"
#include "dwarf2/index-write.h"
#include "dwarf2/read.h"
#include "dwarf2/dwz.h"
#include "objfiles.h"
#include "gdbsupport/selftest.h"
#include <string>
#include <stdlib.h>
/* When set to true, show debug messages about the index cache. */
static bool debug_index_cache = false;
/* The index cache directory, used for "set/show index-cache directory". */
static std::string index_cache_directory;
/* See dwarf-index.cache.h. */
index_cache global_index_cache;
/* set/show index-cache commands. */
static cmd_list_element *set_index_cache_prefix_list;
static cmd_list_element *show_index_cache_prefix_list;
/* Default destructor of index_cache_resource. */
index_cache_resource::~index_cache_resource () = default;
/* See dwarf-index-cache.h. */
void
index_cache::set_directory (std::string dir)
{
gdb_assert (!dir.empty ());
m_dir = std::move (dir);
if (debug_index_cache)
printf_unfiltered ("index cache: now using directory %s\n", m_dir.c_str ());
}
/* See dwarf-index-cache.h. */
void
index_cache::enable ()
{
if (debug_index_cache)
printf_unfiltered ("index cache: enabling (%s)\n", m_dir.c_str ());
m_enabled = true;
}
/* See dwarf-index-cache.h. */
void
index_cache::disable ()
{
if (debug_index_cache)
printf_unfiltered ("index cache: disabling\n");
m_enabled = false;
}
/* See dwarf-index-cache.h. */
void
index_cache::store (dwarf2_per_objfile *per_objfile)
{
objfile *obj = per_objfile->objfile;
if (!enabled ())
return;
/* Get build id of objfile. */
const bfd_build_id *build_id = build_id_bfd_get (obj->obfd);
if (build_id == nullptr)
{
if (debug_index_cache)
printf_unfiltered ("index cache: objfile %s has no build id\n",
objfile_name (obj));
return;
}
std::string build_id_str = build_id_to_string (build_id);
/* Get build id of dwz file, if present. */
gdb::optional<std::string> dwz_build_id_str;
const dwz_file *dwz = dwarf2_get_dwz_file (per_objfile->per_bfd);
const char *dwz_build_id_ptr = NULL;
if (dwz != nullptr)
{
const bfd_build_id *dwz_build_id = build_id_bfd_get (dwz->dwz_bfd.get ());
if (dwz_build_id == nullptr)
{
if (debug_index_cache)
printf_unfiltered ("index cache: dwz objfile %s has no build id\n",
dwz->filename ());
return;
}
dwz_build_id_str = build_id_to_string (dwz_build_id);
dwz_build_id_ptr = dwz_build_id_str->c_str ();
}
if (m_dir.empty ())
{
warning (_("The index cache directory name is empty, skipping store."));
return;
}
try
{
/* Try to create the containing directory. */
if (!mkdir_recursive (m_dir.c_str ()))
{
warning (_("index cache: could not make cache directory: %s"),
safe_strerror (errno));
return;
}
if (debug_index_cache)
printf_unfiltered ("index cache: writing index cache for objfile %s\n",
objfile_name (obj));
/* Write the index itself to the directory, using the build id as the
filename. */
write_psymtabs_to_index (per_objfile, m_dir.c_str (),
build_id_str.c_str (), dwz_build_id_ptr,
dw_index_kind::GDB_INDEX);
}
catch (const gdb_exception_error &except)
{
if (debug_index_cache)
printf_unfiltered ("index cache: couldn't store index cache for objfile "
"%s: %s", objfile_name (obj), except.what ());
}
}
#if HAVE_SYS_MMAN_H
/* Hold the resources for an mmapped index file. */
struct index_cache_resource_mmap final : public index_cache_resource
{
/* Try to mmap FILENAME. Throw an exception on failure, including if the
file doesn't exist. */
index_cache_resource_mmap (const char *filename)
: mapping (mmap_file (filename))
{}
scoped_mmap mapping;
};
/* See dwarf-index-cache.h. */
gdb::array_view<const gdb_byte>
index_cache::lookup_gdb_index (const bfd_build_id *build_id,
std::unique_ptr<index_cache_resource> *resource)
{
if (!enabled ())
return {};
if (m_dir.empty ())
{
warning (_("The index cache directory name is empty, skipping cache "
"lookup."));
return {};
}
/* Compute where we would expect a gdb index file for this build id to be. */
std::string filename = make_index_filename (build_id, INDEX4_SUFFIX);
try
{
if (debug_index_cache)
printf_unfiltered ("index cache: trying to read %s\n",
filename.c_str ());
/* Try to map that file. */
index_cache_resource_mmap *mmap_resource
= new index_cache_resource_mmap (filename.c_str ());
/* Yay, it worked! Hand the resource to the caller. */
resource->reset (mmap_resource);
return gdb::array_view<const gdb_byte>
((const gdb_byte *) mmap_resource->mapping.get (),
mmap_resource->mapping.size ());
}
catch (const gdb_exception_error &except)
{
if (debug_index_cache)
printf_unfiltered ("index cache: couldn't read %s: %s\n",
filename.c_str (), except.what ());
}
return {};
}
#else /* !HAVE_SYS_MMAN_H */
/* See dwarf-index-cache.h. This is a no-op on unsupported systems. */
gdb::array_view<const gdb_byte>
index_cache::lookup_gdb_index (const bfd_build_id *build_id,
std::unique_ptr<index_cache_resource> *resource)
{
return {};
}
#endif
/* See dwarf-index-cache.h. */
std::string
index_cache::make_index_filename (const bfd_build_id *build_id,
const char *suffix) const
{
std::string build_id_str = build_id_to_string (build_id);
return m_dir + SLASH_STRING + build_id_str + suffix;
}
/* True when we are executing "show index-cache". This is used to improve the
printout a little bit. */
static bool in_show_index_cache_command = false;
/* "show index-cache" handler. */
static void
show_index_cache_command (const char *arg, int from_tty)
{
/* Note that we are executing "show index-cache". */
auto restore_flag = make_scoped_restore (&in_show_index_cache_command, true);
/* Call all "show index-cache" subcommands. */
cmd_show_list (show_index_cache_prefix_list, from_tty);
printf_unfiltered ("\n");
printf_unfiltered
(_("The index cache is currently %s.\n"),
global_index_cache.enabled () ? _("enabled") : _("disabled"));
}
/* "set index-cache on" handler. */
static void
set_index_cache_on_command (const char *arg, int from_tty)
{
global_index_cache.enable ();
}
/* "set index-cache off" handler. */
static void
set_index_cache_off_command (const char *arg, int from_tty)
{
global_index_cache.disable ();
}
/* "set index-cache directory" handler. */
static void
set_index_cache_directory_command (const char *arg, int from_tty,
cmd_list_element *element)
{
/* Make sure the index cache directory is absolute and tilde-expanded. */
gdb::unique_xmalloc_ptr<char> abs
= gdb_abspath (index_cache_directory.c_str ());
index_cache_directory = abs.get ();
global_index_cache.set_directory (index_cache_directory);
}
/* "show index-cache stats" handler. */
static void
show_index_cache_stats_command (const char *arg, int from_tty)
{
const char *indent = "";
/* If this command is invoked through "show index-cache", make the display a
bit nicer. */
if (in_show_index_cache_command)
{
indent = " ";
printf_unfiltered ("\n");
}
printf_unfiltered (_("%s Cache hits (this session): %u\n"),
indent, global_index_cache.n_hits ());
printf_unfiltered (_("%sCache misses (this session): %u\n"),
indent, global_index_cache.n_misses ());
}
void _initialize_index_cache ();
void
_initialize_index_cache ()
{
/* Set the default index cache directory. */
std::string cache_dir = get_standard_cache_dir ();
if (!cache_dir.empty ())
{
index_cache_directory = cache_dir;
global_index_cache.set_directory (std::move (cache_dir));
}
else
warning (_("Couldn't determine a path for the index cache directory."));
/* set index-cache */
add_basic_prefix_cmd ("index-cache", class_files,
_("Set index-cache options."),
&set_index_cache_prefix_list,
false, &setlist);
/* show index-cache */
add_prefix_cmd ("index-cache", class_files, show_index_cache_command,
_("Show index-cache options."), &show_index_cache_prefix_list,
false, &showlist);
/* set index-cache on */
add_cmd ("on", class_files, set_index_cache_on_command,
_("Enable the index cache."), &set_index_cache_prefix_list);
/* set index-cache off */
add_cmd ("off", class_files, set_index_cache_off_command,
_("Disable the index cache."), &set_index_cache_prefix_list);
/* set index-cache directory */
add_setshow_filename_cmd ("directory", class_files, &index_cache_directory,
_("Set the directory of the index cache."),
_("Show the directory of the index cache."),
NULL,
set_index_cache_directory_command, NULL,
&set_index_cache_prefix_list,
&show_index_cache_prefix_list);
/* show index-cache stats */
add_cmd ("stats", class_files, show_index_cache_stats_command,
_("Show some stats about the index cache."),
&show_index_cache_prefix_list);
/* set debug index-cache */
add_setshow_boolean_cmd ("index-cache", class_maintenance,
&debug_index_cache,
_("Set display of index-cache debug messages."),
_("Show display of index-cache debug messages."),
_("\
When non-zero, debugging output for the index cache is displayed."),
NULL, NULL,
&setdebuglist, &showdebuglist);
}