Mark J. Wielaard

Hi Fedora Packagers,

rawhide rpmbuild contains various debuginfo improvements that hopefully will make various hacks in spec files redundant.

If you have your own way of handling debuginfo packages, calling find-debuginfo.sh directly, need hacks for working around debugedit limitations or split your debuginfo package by hand then please try out rpmbuild in rawhide and read below for some macros you can set to tweak debuginfo package generation.

If you still need hacks in your spec file because setting macros isn’t enough to get the debuginfo packages you want then please let us know. Also please let us know about packages that need to set debuginfo rpm macros to non-default values because they would crash and burn with the default settings (best to file a bug against rpmbuild).

The improvements have been mainly driven by the following two change proposals for f27 (some inspired by what other distros do):

https://fedoraproject.org/wiki/Changes/ParallelInstallableDebuginfo
https://fedoraproject.org/wiki/Changes/SubpackageAndSourceDebuginfo

The first is completely done and has been enabled by default for some months now in rawhide. The second introduces two new macros to enable separate debugsource and sub-debuginfo packages, but has not been enabled by default yet. If people like the change and no bugs are found (and fesco and releng agree) we can enable them for the f27 mass rebuild.

If your package already splits debuginfo packages in a (common) source package and/or sub-debuginfo packages, please try out the new macros introduced by the second change. You can enable the standard splitting by adding the following to your spec file:

%global _debugsource_packages 1
%global _debuginfo_subpackages 1

Besides the above two changes debuginfo packages can now (and are by default in rawhide) build by running debug extraction in parallel. This should speed up building with lots of binaries/libraries. If you do invoke find-debuginfo.sh by hand you most likely will want to add %{?_smp_mflags} as argument to get the parallel processing speedup.

If your package is invoking find-debuginfo.sh by hand also please take a look at all the new options that have been added. Also note that almost all options can be changed by setting (or undefining) rpm macros now. Using the rpm macros is preferred over invoking find-debuginfo.sh directly since it means you get any defaults and improvements that might need new find-debuginfo.sh arguments automatically.

Here is an overview of various debuginfo rpm macros that you can define undefine in your spec file with the latest rpmbuild:

#
# Should an ELF file processed by find-debuginfo.sh having no build ID
# terminate a build?  This is left undefined to disable it and defined to
# enable.
#
%_missing_build_ids_terminate_build    1

#
# Include minimal debug information in build binaries.
# Requires _enable_debug_packages.
#
%_include_minidebuginfo        1

#
# Include a .gdb_index section in the .debug files.
# Requires _enable_debug_packages and gdb-add-index installed.
#
%_include_gdb_index    1

#
# Defines how and if build_id links are generated for ELF files.
# The following settings are supported:
#
# - none
#   No build_id links are generated.
#
# - alldebug
#   build_id links are generated only when the __debug_package global is
#   defined. This will generate build_id links in the -debuginfo package
#   for both the main file as /usr/lib/debug/.build-id/xx/yyy and for
#   the .debug file as /usr/lib/debug/.build-id/xx/yyy.debug.
#   This is the old style build_id links as generated by the original
#   find-debuginfo.sh script.
#
# - separate
#   build_id links are generate for all binary packages. If this is a
#   main package (the __debug_package global isn't set) then the
#   build_id link is generated as /usr/lib/.build-id/xx/yyy. If this is
#   a -debuginfo package (the __debug_package global is set) then the
#   build_id link is generated as /usr/lib/debug/.build-id/xx/yyy.
#
# - compat
#   Same as for "separate" but if the __debug_package global is set then
#   the -debuginfo package will have a compatibility link for the main
#   ELF /usr/lib/debug/.build-id/xx/yyy -> /usr/lib/.build-id/xx/yyy
%_build_id_links compat

# Whether build-ids should be made unique between package version/releases
# when generating debuginfo packages. If set to 1 this will pass
# --build-id-seed "%{VERSION}-%{RELEASE}" to find-debuginfo.sh which will
# pass it onto debugedit --build-id-seed to be used to prime the build-id
# note hash.
%_unique_build_ids      1

# Do not recompute build-ids but keep whatever is in the ELF file already.
# Cannot be used together with _unique_build_ids (which forces recomputation).
# Defaults to undefined (unset).
#%_no_recompute_build_ids 1

# Whether .debug files should be made unique between package version,
# release and architecture. If set to 1 this will pass
# --unique-debug-suffix "-%{VERSION}-%{RELEASE}.%{_arch} find-debuginfo.sh
# to create debuginfo files which end in -<ver>-<rel>.<arch>.debug
# Requires _unique_build_ids.
%_unique_debug_names    1

# Whether the /usr/debug/src/<package> directories should be unique between
# package version, release and architecture. If set to 1 this will pass
# --unique-debug-src-base "%{name}-%{VERSION}-%{RELEASE}.%{_arch}" to
# find-debuginfo.sh to name the directory under /usr/debug/src as
# <name>-<ver>-<rel>.<arch>.
%_unique_debug_srcs     1

# Whether rpm should put debug source files into its own subpackage
#%_debugsource_packages 1

# Whether rpm should create extra debuginfo packages for each subpackage
#%_debuginfo_subpackages 1

# Number of debugging information entries (DIEs) above which
# dwz will stop considering file for multifile optimizations
# and enter a low memory mode, in which it will optimize
# in about half the memory needed otherwise.
%_dwz_low_mem_die_limit          10000000
# Number of DIEs above which dwz will stop processing
# a file altogether.
%_dwz_max_die_limit              50000000

%_find_debuginfo_dwz_opts --run-dwz\\\
--dwz-low-mem-die-limit %{_dwz_low_mem_die_limit}\\\
--dwz-max-die-limit %{_dwz_max_die_limit}

If there are settings missing that would be useful, bugs with the default settings or defaults that should be changed please do file a bug report.