Ubuntu
llvm-toolchain-3.4 package

  1. Bug #1349789
  2. Comment #2

Comment 2 for bug 1349789

Revision history for this message
Niall Douglas (s-launchpad-k) wrote :

FYI I am one of the Boost core dev team, and this problem emerged during our prerelease testing of Boost 1.56.

I thought a reasonable test of who is at fault would be if I purged all trace of clang and llvm from the system, and then download these prebuilt binaries from llvm:

http://llvm.org/releases/3.4.2/clang+llvm-3.4.2-armv7a-linux-gnueabihf.tar.xz

I unpack these into /usr/local and ensure perms and ownership are reset to correct values.

If I now repeat the earlier test I see:

1. I no longer need to manually override -mcpu, because the correct local CPU is now chosen and the atomics compile instead of the assembler not recognising instructions. I would assume the default triple of armv7a-linux-gnueabihf helps a lot here.

2. All the unit tests still hang in the same place as with your clang.

This suggests to me that something is very wrong with Boost on clang on armhf.

I'll investigate more this end, but fixing the default cpu such that it supports atomics would be a great help, so I'll leave this issue open for now. I'll come back if I figure out the cause of the hangs and it's related to packaging.

Niall