Comment 10 for bug 1026359

While the patch does indeed links the plugin correctly the original example still does not work in multiple ways.

I have installed clang & llvm-3.0 packages:

$ dpkg-query -W llvm-3.0
llvm-3.0 3.0-9ubuntu1
$ dpkg-query -W clang
clang 3.0-6ubuntu3
$ cat foo.c
int main(){return 0;}
$ clang -O4 -use-gold-plugin foo.c
/usr/bin/ld.bfd.real: /usr/bin/../lib/LLVMgold.so: error loading plugin
/usr/bin/ld.bfd.real: /usr/bin/../lib/LLVMgold.so: error in plugin cleanup (ignored)
clang: error: linker command failed with exit code 1 (use -v to see invocation)
$ ld.gold -v -plugin /usr/lib/llvm-3.0/lib/LLVMgold.so
GNU gold (GNU Binutils for Ubuntu 2.22.90.20120816) 1.11
/usr/bin/ld.gold.real: error: /usr/lib/llvm-3.0/lib/LLVMgold.so: could not load plugin library: libLTO.so: cannot open shared object file: No such file or directory

So there is a missing dependency.... on llvm-dev (well current default llvm-3.0-dev)
To me this sounds a bit counter-intuitive, but maybe that's just the way to package llvm.
But why split the packages, if they still depend on each other....?

After installing llvm-dev I get slightly better results:

$ clang -O4 -use-gold-plugin foo.c -o foo
/tmp/foo-nf9h1L.o: file not recognized: File format not recognised
clang: error: linker command failed with exit code 1 (use -v to see invocation)

but...

$ clang -O3 -use-gold-plugin foo.c -o foo && echo $?
0

So is -O4 broken with gold linker?

This fix looks sane and I can test is by inspection with ldd, but can I tell clang to use a different LLVM? Cause clang is currently compiled against llvm-3.0, not llvm-3.1.