JezK
Edit File: dh_dwz
#!/usr/bin/perl =head1 NAME dh_dwz - optimize DWARF debug information in ELF binaries via dwz =cut use strict; use warnings; use File::Find; use Debian::Debhelper::Dh_Lib; our $VERSION = DH_BUILTIN_VERSION; =head1 SYNOPSIS B<dh_dwz> [S<I<debhelper options>>] [B<-X>I<item>] [S<B<--> I<params>>] =head1 DESCRIPTION B<dh_dwz> is a debhelper program that will optimize the (uncompressed) size of the DWARF debug information in ELF binaries. It does so by running L<dwz(1)> on all the ELF binaries in the package. =head1 OPTIONS =over 4 =item B<--dwz-multifile>, B<--no-dwz-multifile> Whether L<dwz(1)> should generate a I<multifile> from the ELF binaries in the same package. When enabled, if a package ships at least 2 ELF binaries, B<dh_dwz> will instruct L<dwz(1)> to generate a multifile for the package. By default, B<dh_dwz> will attempt to create a multifile but will continue without if L<dwz(1)> does not create one (but succeeds anyway). This commonly happens when the debug files do not contain debug symbols (e.g. a missing -g to the compiler) or when the debug symbols are compressed (see Debian bug #931891). If B<--dwz-multifile> is passed, then B<dh_dwz> will abort with an error if L<dwz(1)> does not create a multifile. Note this options may not work if a package contains more ELF binaries than can fit on a single command line. If this becomes a problem, please pass B<--no-dwz-multifile> to work around the issue. The generated multifile will be compressed with B<objcopy --compress-debug-sections>. Note for B<udeb> packages: B<dh_dwz> will never generate multifiles for B<udeb> packages. It will still use B<dwz> to reduce the file size of debug files if it finds any. =item B<-X>I<item>, B<--exclude=>I<item> Exclude files that contain I<item> anywhere in their filename from being stripped. You may use this option multiple times to build up a list of things to exclude. =item B<--> I<params> Pass I<params> to L<dwz(1)> when it processes ELF binaries. This is mostly useful for setting memory related parameters (e.g. -l and -L). =back =head1 NOTES If the B<DEB_BUILD_OPTIONS> environment variable contains B<nostrip>, nothing will be stripped, in accordance with Debian policy (section 10.1 "Binaries"). While this tool technically does not remove debug information from binaries, it is still skipped when the B<DEB_BUILD_OPTIONS> environment variable contains B<nostrip>. This is because B<nostrip> is often used to optimize build times (e.g. for "build and test"-cycles) rather than optimizing for size. =cut my $create_multifile = 'auto'; init(options => { 'dwz-multifile!' => \$create_multifile, }); # This variable can be used to turn off stripping (see Policy). exit 0 if get_buildoption('nostrip'); my @elf_files; sub testfile { my $fn = $_; return if -l $fn; # Always skip symlinks. # See if we were asked to exclude this file. # Note that we have to test on the full filename, including directory. if (excludefile($fn)) { $File::Find::prune = 1 if -d _; return; } return if -d _; # Do not process output files from dwz return if index($fn, '/debug/.dwz/') > -1; if (is_so_or_exec_elf_file($fn)) { push(@elf_files, $fn); } return; } on_items_in_parallel(\@{$dh{DOPACKAGES}}, sub { foreach my $package (@_) { my $tmp = tmpdir($package); next if not -d $tmp; @elf_files = (); find({ wanted => \&testfile, no_chdir => 1, }, $tmp); next if not @elf_files; # Consistent order; @elf_files = sort(@elf_files); my ($unique_files, $hardlinks) = find_hardlinks(@elf_files); if ($create_multifile and @{$unique_files} > 1 and not is_udeb($package)) { my $objcopy = cross_command($package, 'objcopy'); my $ma_dir = dpkg_architecture_value('DEB_HOST_MULTIARCH'); my $dwz_dir = "usr/lib/debug/.dwz/${ma_dir}"; my $m = "${dwz_dir}/${package}.debug"; my @dwz_options = ("-m${tmp}/${m}", "-M/${m}"); install_dir("${tmp}/${dwz_dir}"); doit('dwz', @dwz_options, @{$dh{U_PARAMS}}, '--', @{$unique_files}); if ( -f "${tmp}/${m}") { doit($objcopy, '--compress-debug-sections', "${tmp}/${m}"); reset_perm_and_owner(0644, "${tmp}/${m}"); } else { error("dwz failed to create a multifile as requested") if $create_multifile ne 'auto'; warning("No dwz multifile created, but not explicitly requested either so ignoring it."); warning("Common issues include no debug information at all (missing -g) and"); warning("compressed debug information (#931891)."); # Clean up after ourselves to avoid leaving empty directories in packages doit('rmdir', '-p', '--ignore-fail-on-non-empty', "${tmp}/${dwz_dir}"); } } else { xargs($unique_files, 'dwz', @{$dh{U_PARAMS}}, '--'); } # Now change over any files we can that used to be hard links so # they are again. for my $hardlink (keys %{$hardlinks}) { my $target = $hardlinks->{$hardlink}; # Remove old file. rm_files($hardlink); # Make new hardlink. doit('ln', '-f', $target, $hardlink); } }}); =head1 SEE ALSO L<debhelper(7)> This program is a part of debhelper. =head1 AUTHOR Niels Thykier <niels@thykier.net> =cut