Linking errors while compiling against static libraries on Ubuntu 20.04 LTS

[olegded]

Hi Robert,

I have tried to build vsgXchange against default static glslang libraries installed via native package manager on Ubuntu 20.04 LTS. It looks like that this Ubuntu version includes latest glslang version including breaking changes as described here, see deletion of glslang/Include/revision.h.

Somewhat easy change is to fix <glslang/Include/revision.h> include here, although it requires changes to "#if GLSLANG_PATCH_LEVEL > 3727" test to make it right.

However, what I really failed so far is to link against the static libraries resulting in tons of linker errors. I have tried to change add_library(glslang::glslang UNKNOWN IMPORTED) to add_library(glslang::glslang STATIC IMPORTED) (and all subsequent libraries further in the CMake file), still no success. I couldn't figure out whether set_target_properties calls need some changes or not, at least I cannot find which flags would be required here.

Latest self-compiled glslang master branch using dynamic libraries works. This issue can be reproduced by compiling latest glslang master as static libraries under Ubuntu 20.04 LTS.

Do you have an idea what might be missing?

Regards,
Oleg

[robertosfield]

Hi Oleg,

On Wed, 2 Sep 2020 at 22:58, olegded ***@***.***> wrote: I have tried to build vsgXchange against default static glslang libraries installed via native package manager on Ubuntu 20.04 LTS. It looks like that this Ubuntu version includes latest glslang version including breaking changes as described here <KhronosGroup/glslang#2277>, see deletion of glslang/Include/revision.h. Somewhat easy change is to fix <glslang/Include/revision.h> include here <https://github.com/vsg-dev/vsgXchange/blob/master/src/glsl/ResourceLimits.cpp#L41>, although it requires changes "#if GLSLANG_PATCH_LEVEL > 3727" test <https://github.com/vsg-dev/vsgXchange/blob/master/src/glsl/ResourceLimits.cpp#L139-L141> to make it right. However, what I really failed so far is to link against the static libraries resulting in tons of linker errors. I have tried to change add_library(glslang::glslang UNKNOWN IMPORTED) <https://github.com/vsg-dev/vsgXchange/blob/master/src/glslangConfig.cmake#L147> to add_library(glslang::glslang STATIC IMPORTED) (and all subsequent libraries further in the CMake file), still no success. I couldn't figure out whether set_target_properties calls need some changes or not, at least I cannot find which flags would be required here. Latest self-compiled glslang master branch <https://github.com/KhronosGroup/glslang> using dynamic libraries works. Do you have an idea what might be missing?

I don't know what is missing. I'll try it first hand today as I now have a Kubuntu 20.04 install as a dual boot on my dev system, I have it building against VulkanSDK but that doesn't help recreate the issue you are seeing. What were the package names you used of glslang and vulkan? One thing I'm considering is to see how easy it would be to make glslang a submodule which is built locally. Robert.

[olegded]

• Vulkan SDK is at 1.2.148.0, updated as described here Ubuntu packages - libvulkan1/libvulkan-dev, lunarg and vulkan* packages

• glslang-dev, glslang-tools, v8.13.3743+193-1ubuntu20.04-2

I guess using VulkanSDK could break things too when it will be updated to the latest version (at least the breaking change).

Really wondering if there any difference between installing the VulkanSDK via tarball or provided Ubuntu packages. Ubuntu packages look like easier to update via system tools.

[robertosfield]

Hi Oleg,

On Thu, 3 Sep 2020 at 09:26, olegded ***@***.***> wrote: - Vulkan SDK is at 1.2.148.0, updated as described here Ubuntu packages <https://vulkan.lunarg.com/sdk/home#linux> - libvulkan1/libvulkan-dev, lunarg and vulkan* packages - glslang-dev, glslang-tools, v8.13.3743+193-1ubuntu20.04-2

I've moved across to Kubuntu 20.04, remove VulkanSDK from my search path, installed all the above and VSG, vsgXchange & vsgExamples all builds and link cleanly, The only problem I had was when I didn't install glslang-tools and vsgXchange couldn't find the SPIRV-Tools libs and build and attempted a link anyway, which suggest these are now required libs rather than options. So are you still getting compile errors with VSG, vsgXchange & vsgExamples master and the above installed libvulkan-dev, glslang-dev and glslang-tools?

[olegded]

Yes and I definitely don't have glslang/Include/revision.h resulting in a compiler error. I would say having a self-compiled version with dynamic libraries is a working solution/workaround. Maybe it's worth to add an install readme file describing how to install known working version of the glslang library.

[robertosfield]

Hi Oleg,

On Thu, 3 Sep 2020 at 13:40, olegded ***@***.***> wrote: Yes and definitely don't have glslang/Include/revision.h resulting in a compiler error.

Curious. My install did have this header - my system compiled without any changes. I wonder if ubuntu has issued a patch for this.

I would say having a self-compiled version with dynamic libraries is a working solution/workaround. Maybe it's worth to add an install readme file describing how to install known working version of the glslang library.

I'm currently looking at the glslang repository on github. They look to have a bit of lets break 3rd party code spree, indicative of projects more focused on runtimes rather than focused on 3rd parties linking the libs to do shader compilation/validation. I haven't figured out a route through this mess with glslang shifting the goal posts in ways that make it hard to keep code compiling against newer and older versions of glslang. I will look at the practicality of just checking out and building glslang locally. If the VSSG/vsgXchange is built statically then it'd make sense to link glslang statically as well, and match the dynamic build if this is used as well. I'd much rather be working on developing the VSG itself rather than trying to figure out how to cope with libs like glslang breaking code. Reminds me of the problems working with ffmpeg and Apple over the years... Robert.

[olegded]

Hi Robert,

I can confirm that both vsgExamples and MyFirstVsgApplication can be built now on Ubuntu 20.04 using latest self-compiled glslang master (compiled as static libraries).

Oleg