windows-2022 and 2025 runners' LLVM 20.1.7 installations lack llvm-config.exe

[lgritz]

Description

For the current LLVM install in the Windows runners, the C:\Program Files\LLVM\bin directory seems to lack the expected llvm-config.exe binary. Is this on purpose? That executable is vital for downstream projects to query configuration options such as the full set of library paths needed to link against llvm, etc.

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 22.04
• Ubuntu 24.04
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

Version: 20250629.1.0
Version: 20250701.1.0

Is it regression?

unknown

Expected behavior

There should be a C:\Program Files\LLVM\bin\llvm-config.exe

Actual behavior

There is no C:\Program Files\LLVM\bin\llvm-config.exe

Repro steps

ls $PROGRAMFILES/LLVM/bin | grep llvm-config

[kishorekumar-anchala]

Hi @lgritz - Thank you for bringing this issue to our attention. We will look into this issue and will update you after investigating

[lgritz]

Thanks. I'm also not 100% sure that everything else is there. A thing to definitely look into is whether your installed "LLVM" is actually the full LLVM (the JIT libraries and everything), or it's only the parts of LLVM directly needed by clang and related utilities.

[RaviAkshintala]

@lgritz We are installing LLVM via Chocolatey. However, this package includes only a limited set of components and does not contain the full LLVM distribution, such as the JIT libraries, shared libraries, development headers, and utilities like llvm-config.

If you require the complete LLVM functionality—including JIT support and all development libraries, you will need to build LLVM from source. Thanks.

[lgritz]

I think you should not be documenting that you have LLVM installed on the runners if it's not really the full LLVM installation! Maybe call it "LLVM command line utilities (no development libraries)" or something else that would prevent people wasting a lot of time trying to make it work before figuring out that you don't really have LLVM pre-installed.

I'm not really a Windows developer, so maybe this is a cultural expectation I'm just not used to.
What about the other packages you list for the Windows runners? How are we supposed to know which can be counted on as being the full legit installations, and which should be ignored and built from source despite being documented as pre-installed?

I'm not quite sure how to proceed now. I'm pretty sure that building all of llvm from source actually takes longer than the maximum job time on the runners.

[RaviAkshintala]

@lgritz The runner image includes only the LLVM command-line tools, not the full development libraries. This helps keep the image lightweight. We understand this can be confusing, If we see more feedback like this, we’ll also consider adding more complete installations in the future. We are closing this issue now. Thank you.