I found out LLVM 3.6 + Mesa 10.5 (and newer) might have some sort of regression
breaking opengl with radeonsi drivers at least.
I use genymotion (android emulator) which relies on virtualbox and make use of
opengl acceleration.
On 2 different machines with 2 different distros (ubuntu 14.10/15.04 and
manjaro 0.9 pre4) I had the same problem: as soon as LLVM 3.6 or 3.7git (the
latter with utopic when I added paulo dias ppa) gets installed
genymotion stop working (the screen of the vm disappear 1-2 seconds after the
machine gets started, and while the screen disappear the machine keeps running
in the background).
On the terminal I get this error:
Port 22468 will be used for OpenGL data connections
Unknown TCPCLI command 1003
LLVM ERROR: 'main' label emitted multiple times to assembly file
With LLVM 3.5 genymotion (with the same distros and machines) was working just
fine.
Another proof that the issue is with LLVM is that as to temporarily sort this
problem out, I installed the proprietary drivers (fgrlx) and the issue vanished
(since proprietary drivers do not make use of LLVM).
To reproduce the bug, you need a radeon vga (possibly one using the radeonsi
drivers so with GCN architecture) , install vitualbox and genymotion, Setup a
virtual device and having installed LLVM 3.6 or newer. Then start the device
you created.
I reported this bug to the llvm bug-tracker system and they told me to report
it to you.