LLVM symbols should be versioned to avoid crashing applications that load mesa's swrast and also use a different libLLVM

[RJVB]

The libgl1-mesa-dri-lts-xenial package depend on libLLVM-3.8.so.1 from the libllvm3.8v4 package; this library gets used when using software OpenGL rendering on a remote display. As a result, applications based on Qt5 that also use libLLVM features provided by another (newer) LLVM version will crash when invoked from a remote X terminal.

Example: KDevelop5 uses libclang (and this libLLVM) for C/C++ parsing; I build it to use the LLVM/Clang 4.0 packages from llvm.org (and self-built Qt5 and KF5 libraries) and can thus not render to a remote X server (XQuartz on my Mac).

There is an upstream LLVM patch which solves the issue by adding versioning info to libLLVM:

https://bugs.kde.org/show_bug.cgi?id=373614
https://reviews.llvm.org/D31524

Please consider backporting this patch to LLVM 3.8 (or rebuilding the mesa package to use a (much) more recent LLVM version that already contains the patch).

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Rebecca Palmer (rebecca-palmer)]

Current llvm-toolchain-* packages do have versioned symbols (since 3.8.1-22 / 3.9.1-8 / 4.0-5: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=849098), but this 3.8 has not been backported.

Note that loading the *same* LLVM version twice can also crash, for a different reason: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=852746

[RJVB (rjvbertin)]

It seems that this could have been backported by now, the ticket has been open for (almost) a year now ...

In the end I got fed up with having to point the library used by Mesa/Gallium to the much newer one I also use (something kept resetting it), and uninstalled the corresponding Mesa component. Problem not solved but gone all the same (and I don't notice any difference other than that certain applications no longer crash).