BTW I think some history may be at work here. clang didn't support native cpu detection back when I was the chief clang person at BlackBerry, it may well still not. I would assume the default choice of arm-linux-gnueabihf, judging from google searching, was mainly driven by RaspPI enthusiasts who obviously wanted an ARMv6 clang. Now, a Cortex-A8 supports atomics just fine, but it could be that arm-linux-gnueabihf means one thing to GCC (an ARMv6) and something rather less (an ARM7tdmi for example, the lowest supported ARM CPU) to clang which is ARMv4 or something.
It might be worth experimenting with a default triple for clang of armv6 -linux-gnueabihf instead. After all, Ubuntu surely does not work on systems without atomics. I'll give this a try on Saturday and see what happens. BTW there is something real weird in Boost on clang armhf, exception throw catches aren't reliable, this was causing an infinite loop of terminate(). I'd say 1.56 is going to ship anyway, I'll see if I can figure out the problem for 1.57, again this will be Saturday. Niall -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to llvm-toolchain-3.4 in Ubuntu. https://bugs.launchpad.net/bugs/1349789 Title: clang armhf in trusty simply doesn't work Status in “llvm-toolchain-3.4” package in Ubuntu: Confirmed Bug description: I'm running Ubuntu 14.04 on armhf. clang is from the standard repo: root@tegra-ubuntu:~# apt-cache show clang Package: clang Priority: optional Section: universe/devel Installed-Size: 27 Maintainer: Ubuntu Developers <ubuntu-devel-disc...@lists.ubuntu.com> Original-Maintainer: LLVM Packaging Team <pkg-llvm-t...@lists.alioth.debian.org> Architecture: armhf Source: llvm-defaults (0.21ubuntu1) Version: 1:3.4-0ubuntu1 Replaces: clang (<< 3.2-1~exp2) Depends: clang-3.4 (>= 3.4~rc3-1~) Filename: pool/universe/l/llvm-defaults/clang_3.4-0ubuntu1_armhf.deb Size: 2478 MD5sum: eadb3f7c344e364480bdf7fdd0f698ab SHA1: ec4d0bfcad42bf536ee8d9257f8930dd32e1a261 SHA256: f6d9a8fbfc06d93cd4c1a2437114454cc1eec805a635efc490a7e1e6eec2b3de Description-en: C, C++ and Objective-C compiler (LLVM based) Clang project is a C, C++, Objective C and Objective C++ front-end for the LLVM compiler. Its goal is to offer a replacement to the GNU Compiler Collection (GCC). . Clang implements all of the ISO C++ 1998 and 2001 standards and also provides a partial support of C++1y. . This is a dependency package providing the default clang compiler. Description-md5: ea1f164ac255f39c6ec78685f71ef19b Bugs: https://bugs.launchpad.net/ubuntu/+filebug Origin: Ubuntu Anyway, it does not produce working output. Here are some examples: https://ci.nedprod.com/view/Boost.AFIO/job/Boost.AFIO%20Build%20POSIX_ARM_clang%203.4/9/consoleFull This log shows how clang has the wrong default target CPU, so it outputs unsupported ARM instructions (see the end after the warnings spew). If I force the target cpu to a cortex-a15 it now at least compiles and links and starts to run unit tests: https://ci.nedprod.com/view/Boost.AFIO/job/Boost.AFIO%20Test%20POSIX_ARM_clang%203.4/7/consoleFull ... but hangs in the first unit test, and is timed out. Before you think it the unit tests, here is the exact same thing for GCC 4.8: https://ci.nedprod.com/view/Boost.AFIO/job/Boost.AFIO%20Test%20POSIX_ARM_GCC%204.8/7/console The unit tests all run and pass as expected. Everything also works fine on x86 and x64 with clang 3.4 on Ubuntu 14.04, this appears to be an armhf misconfiguration. Niall To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-3.4/+bug/1349789/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
