[Mesa-dev] radv vs vulkan loader

[Emil Velikov]

On 5 October 2016 at 21:45, Gustaw Smolarczyk <wielkiegie at gmail.com> wrote:
> Hello,
>
> I have encountered a following problem while trying to use radv
> through LunarG's vulkan loader.
>
> It seems that the loader dlopens() the ICD library twice. First, it
> looks up "vk_icdNegotiateLoaderICDInterfaceVersion" symbol, which
> seems to be the new mechanism used to determine the version of ICD
> interface. Since radv doesn't provide it, it fall backs to the older
> scheme. Unfortunately, it seems that the loader first unloads the ICD
> and then loads it again. That causes issues in LLVM libraries' command
> line registration which happens while initializing global objects with
> constructors. To be more specific, "asan-instrument-assembly"
> registered in libLLVMX86AsmPrinter.so registers for the second time
> and causes the following message:
>
>
> $ vulkaninfo
> ===========
> VULKAN INFO
> ===========
>
> Vulkan API Version: 1.0.26
>
>
> : CommandLine Error: Option 'asan-instrument-assembly' registered more
> than once!
> LLVM ERROR: inconsistency in registered CommandLine options
>
> I have "fixed" the problem by manually removing
> libLLVMX86AsmPrinter.so from the list of llvm dependencies to radv. It
> seems that it was the only library registering any command line
> option.
>
> I am not sure who is to blame for this situation. It's possible that
> advertising the new ICD entry point would fix it. LLVM is really
> fragile about its command line registration framework. Last, the
> vulkan loader could try not to unnecessarily dlclose and dlopen the
> ICD library.
>
>From a quick read it sounds like something that should be fixed in
LLVM. Namely: if a library sets up a state it should cleanup after
itself.

That aside, does the radv vulkan driver have unresolved/undefined
symbols (check via $ldd -r libvulkan_foo.so) with your workaround ? If
not we {c,sh}ould drop the library from the link chain. Alternatively
you can try static linking LLVM by using --disable-llvm-shared-libs at
mesa configure time.

-Emil