Introducing GNU gold
Gold is a linker for ELF files. It was added to binutils March, 2008 and first released in binutils version 2.19. Gold is developed by Ian Lance Taylor and a small team at Google with participation of general GNU community. The motivation for writing gold was to make a linker that is faster than the GNU linker, especially for large applications coded in C++. Gold is known to work on x86 and x86-64, PowerPC (partially) and ARM. Gold is intended to link faster but may not support that much architectures as original GNU ld does however distributions, like Fedora, which primary supports GNU gold supported architectures may make it default linker in the future.
gold`s state in Fedora
GNU gold is in Fedora since binutils 2.19 release but was not built until recently. In binutils-2.20.51.0.2-7 (F-13/rawhide that time) we build gold as alternative linker to ld. Via /usr/sbin/alternatives we have /usr/bin/ld which is symbolic link to either /usr/bin/ld.bfd (original ld), or /usr/bin/ld.gold. By default /usr/bin/ld links to BFD ld but altering spec file is easily possible.
Before Fedora may uses gold as primary linker, several things have to be assured
- gold is stable and feature full, so linked apps generally work,
- gold is supported and available for Fedora-supported architectures,
- gold gives speed benefits, and
- Fedora application stack is capable of being linked by gold
gold-rebuild script
Basics
gold-rebuild is a Bash script which utilizes Mock, rpm-build, createrepo, yum and gold itself to rebuild, hence the name, Fedora packages or even whole comps groups and link resulted object files with gold instead of ld. For this purpose builds daily binutils CVS snapshot from trunk as part of Rawhide binutils SRPM and installs resulted new binutils packages to repository reachable by Mock. If rebuild of particular package fails it`s logged and failure is guess-classified to state what might be the problem.
General Capabilities
Usage: gold-rebuild [OPTION]...
Link programs with gold linker.
-c, --color Output in colors.
-r, --rebuild Rebuild current binutils snapshot,
create Yum for Mock repository and use it.
Without --rebuild we use distribution binutils.
-g, --group <GROUP> Select Fedora comps GROUP to rebuild.
-p, --package <P1,...> Comma separated list of packages to
rebuild. Mutual exclusive with '-g'.
-t, --target <ARCH> Target arch (e.g. i686 at x86_64 box).
-o, --os-release <OS> Fedora release from which to take
packages (e.g. 12, 13, ...).
-h, --help Display this help and exit.
-v, --version Output version information and exit.
-q, --quiet Be as quiet much as possible.
-d, --debug Be as verbose as possible.
Examples:
gold-rebuild -c -r Run with colors enabled and well as with
rebuild on.
gold-rebuild Run with defaults (colors=off, etc).
Report gold-rebuild bugs to mnowak@redhat.com
gold-rebuild home page: <http://mnowak.fedorapeople.org/gold-rebuild/>