Fix init-compiler.sh for older clang

[jakubch1]

Latest changes made by PR #8189
broke our build:

clang-5.0 : error : invalid linker name in argument '-fuse-ld=lld' [/__w/1/s/src/Microsoft.VisualStudio.Coverage.InstrumentationMethod/Microsoft.VisualStudio.Coverage.InstrumentationMethod.proj]
##[error]clang-5.0(0,0): error : (NETCORE_ENGINEERING_TELEMETRY=Build) invalid linker name in argument '-fuse-ld=lld'

probably the reason is that we use older clang. If I correctly understand that we can check if clang is at least 9 before even checking for this -fuse-id.

[jakubch1]

@omajid could you please check those changes?

[premun]

This will probably unblock one of the issues in dotnet/runtime#61668?

dotnet/runtime#61668 (comment)

[omajid]

I am testing it out now to see if this still works for me.

cc @am11 @janvorli

[janvorli]

Isn't the issue actually caused by the fact that we output the error message and our CI seeing an output with "error" thinks there was a failure? Wouldn't we get the same message in case the lld was not installed even with newer clang versions? I wonder if we would also need to redirect the output to /dev/null.

[am11]

Isn't the issue actually caused by the fact that we output the error message and our CI seeing an output with "error" thinks there was a failure?

Yes, this is bizarre. Only reason to redirect to stdin was so we can see the message in logs, but /dev/null is fine since something in the pipeline is not liking the text error:..

@janvorli, just curious shouldn't we be using clang 9 at minimum in all CI legs since .NET Core 3?

[jakubch1]

@janvorli redirecting to /dev/null worked for our pipeline (without changing ifs order). I can add it to PR also. WDYT?

[am11]

Your ordering looks fine too. We don't need two separate conditions for compiler and its version.

[janvorli]

I can add it to PR also. WDYT?

Yes, please.

[jakubch1]

Isn't the issue actually caused by the fact that we output the error message and our CI seeing an output with "error" thinks there was a failure?

Yes, this is bizarre. Only reason to redirect to stdin was so we can see the message in logs, but /dev/null is fine since something in the pipeline is not liking the text error:..

@janvorli, just curious shouldn't we be using clang 9 at minimum in all CI legs since .NET Core 3?

Our pipeline is code coverage related. It's not part of dotnet/runtime repository.

[janvorli]

shouldn't we be using clang 9 at minimum in all CI legs since .NET Core 3?

Clang 5.0 is the one available on Alpine <= 3.9. Based on https://docs.microsoft.com/en-us/dotnet/core/install/linux, we support Alpine >= 3.8 on .NET 3.1.

[premun]

Are we happy like this, should we merge?

[jakubch1]

I think we can. Conditions are merged and error output is going to /dev/null

[premun]

Ok, merging to unblock runtime asap. If there are some objections from @janvorli or @am11 we can address them in later