clang -O4 fails with gold in a trivial example

[Dimitri John Ledkov]

$ echo 'int main(){return 0;}' > foo.c
$ clang -v -O4 -use-gold-plugin foo.c -o foo
Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
 "/usr/bin/clang" -cc1 -triple x86_64-pc-linux-gnu -emit-llvm-bc -disable-free -disable-llvm-verifier -main-file-name foo.c -mrelocation-model static -mdisable-fp-elim -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-linker-version 2.22 -momit-leaf-frame-pointer -v -resource-dir /usr/bin/../lib/clang/3.0 -fmodule-cache-path /var/tmp/clang-module-cache -internal-isystem /usr/local/include -internal-isystem /usr/bin/../lib/clang/3.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /usr/include -O3 -ferror-limit 19 -fmessage-length 142 -fgnu-runtime -fobjc-runtime-has-arc -fobjc-runtime-has-weak -fobjc-fragile-abi -fdiagnostics-show-option -fcolor-diagnostics -o /tmp/foo-VnFyCO.o -x c foo.c
clang -cc1 version 3.0 based upon llvm 3.0 hosted on x86_64-pc-linux-gnu
ignoring nonexistent directory "/usr/bin/../lib/clang/3.0/include"
ignoring nonexistent directory "/usr/bin/../lib/clang/3.0/include"
ignoring duplicate directory "/usr/local/include"
ignoring duplicate directory "/usr/include/x86_64-linux-gnu"
ignoring duplicate directory "/usr/include/x86_64-linux-gnu"
ignoring duplicate directory "/usr/include/x86_64-linux-gnu"
ignoring duplicate directory "/usr/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/include/x86_64-linux-gnu
 /usr/include
 /usr/include/clang/3.0/include/
 /usr/lib/gcc/x86_64-linux-gnu/4.6/include/
 /usr/lib/gcc/x86_64-linux-gnu/4.6/include-fixed/
End of search list.
 "/usr/bin/ld" -z relro --hash-style=gnu --as-needed --build-id --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o foo /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crti.o /usr/lib/gcc/x86_64-linux-gnu/4.6/crtbegin.o -L/usr/lib/gcc/x86_64-linux-gnu/4.6 -L/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu -L/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib64 -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/../lib64 -L/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu -L/usr/lib/gcc/x86_64-linux-gnu/4.6/../../.. -L/lib/x86_64-linux-gnu -L/lib -L/usr/lib/x86_64-linux-gnu -L/usr/lib /tmp/foo-VnFyCO.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-linux-gnu/4.6/crtend.o /usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crtn.o -plugin /usr/bin/../lib/LLVMgold.so
/tmp/foo-VnFyCO.o: file not recognized: File format not recognised
clang: error: linker command failed with exit code 1 (use -v to see invocation)
---
ApportVersion: 2.5.1-0ubuntu2
Architecture: amd64
DistroRelease: Ubuntu 12.10
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
Package: llvm-3.1
PackageArchitecture: amd64
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm-256color
 PATH=(custom, user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 3.5.0-11.11-generic 3.5.2
Tags: quantal running-unity
Uname: Linux 3.5.0-11-generic x86_64
UpgradeStatus: Upgraded to quantal on 2012-01-04 (236 days ago)
UserGroups: adm admin cdrom dialout kvm libvirtd lp lpadmin plugdev sambashare sbuild vboxusers

[Dimitri John Ledkov (xnox)]

apport information

[Felix Geyer (debfx)]

-use-gold-plugin only works if you are actually using the gold linker.
For example by passing -B/usr/lib/gold-ld to clang.

[Dimitri John Ledkov (xnox)]

Ok. that works. I should RTFM =)

[Matthias Klose (doko)]

maybe it would be a good idea to add that option automatically