I have been trying to enable the gold linker on FreeBSD to use the link
time optimizations. I made gold from the binutils under /usr/ports. After
building binutils using make -k install clean i got ld under /usr/bin and
in the directory /usr/local/bin i got ld, ld.gold and ld.bfd.
Now while trying to use link time optimization for the simple example
programs herehttp://llvm.org/docs/GoldPlugin.html (a.c and b.c under the
heading 'Examples of Link Time Optimization') i entered the four commands
as follows:
clang -flto a.c -c -o a.o
ar q a.a a.o
clang b.c -c -o b.o
clang -flto a.a b.o -o main
I got the following error:
usr/bin/ld: unrecogonized option '-plugin'
usr/bin/ld: use the --help option for usage information
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Is there the problem with the linker that ld.gold is not being called.
Should I replace the ld with ld.gold? Does the linker looks in the right
directiry for the .so plugins?
The LLVMgold.so and libLTO.so shared objects are in the directory
/usr/local/llvm-devel/lib/. I cannot find the directory where clang is
installed. I am not sure where to make the bfd-plugins directory and add
the symlinks to LLVMgold.so and libLTO.so.
I am using freebsd 10.1 release. How to enable the gold linker for link
time optimizations? also how can I enable it to be the default linker?
Two options:
* Try passing -fuse-ld=gold to clang.
* have 'ld' be a symlink to ld.gold.
Cheers,
Rafael
the symlink ld is already pointing to /usr/bin/ld. Also -fuse-ld=gold does not works on clang in freebsd. I am not sure where is the problem?should I remove /usr/bin/ld and create a new symlink to /usr/local/bin/ld.gold?
Are you sure? We were carrying that one as a patch set on the clang that FreeBSD distributes before it was upstreamed.
David
Aditya: I would think that /usr/bin/ld would be BSD ld. Can you verify whether /usr/bin/ld is ld.bfd or ld.gold? If it’s not ld.gold, it won’t use the Gold plugin. Rafael: Does -fuse-ld=gold cause Clang to look for ld.gold, or does it just cause Clang to pass the need command-line options to ld to get it to use the gold plugin? Ideally, I’d like to not have to manually modify things in /usr/bin to get the Gold plugin working on FreeBSD. I would think that it makes systems upgrades a nightmare. Regards, John Criswell
Rafael:
Does -fuse-ld=gold cause Clang to look for ld.gold, or does it just cause
Clang to pass the need command-line options to ld to get it to use the gold
plugin? Ideally, I'd like to not have to manually modify things in /usr/bin
to get the Gold plugin working on FreeBSD. I would think that it makes
systems upgrades a nightmare.
It causes clang to use ld.gold:
$ clang test.o -o test.so -shared -fuse-ld=gold -v
...
"/home/espindola/inst/binutils/bin/ld.gold" ....
Cheers,
Rafael