Support optionally building AMD64 with tailcalling

[chris-eibl]

cc @zooba

• add a new parameter DoTailcalling: "Build AMD64 with tailcalling support (3.15 and later)"
• if it is true, 'windows-2025-vs2026' is chosen automatically, since this is the only vmImage that can be used in this case
• Only AMD64 release and PGO configuration get the additional parameter --tail-call-interp added to ExtraOptions / ExtraOptionsFreethreaded, since no other configurations support tailcalling

[zooba]

Only AMD64 release and PGO configuration get the additional parameter --tail-call-interp added to ExtraOptions / ExtraOptionsFreethreaded, since no other configurations support tailcalling

They should ignore the option then, right? So applying it to everything is easier.

[chris-eibl]

They don't ignore it - yet and will fail during build.

I think we shouldn't pass the option and then silently ignore it during building?

Even though that'll make things much easier here in azure pipelines, since I could add them unconditionally to

 - ${{ if and(eq(parameters.DoMSI, 'true'), eq(parameters.TestMSI, 'true')) }}:
- template: stage-test-msi.yml
parameters:
DoFreethreaded: ${{ parameters.DoFreethreaded }}
- ${{ if eq(parameters.DoNuget, 'true') }}:
- template: stage-test-nuget.yml
parameters:
DoFreethreaded: ${{ parameters.DoFreethreaded }}
- ${{ if eq(parameters.DoPyManager, 'true') }}:
- template: stage-test-pymanager.yml
parameters:
DoEmbed: ${{ parameters.DoEmbed }}
DoFreethreaded: ${{ parameters.DoFreethreaded }}

etc?

[chris-eibl]

I hope my last commit will work out.

Maybe

ExtraOptions: ${{ if(eq(parameters.DoTailcalling, 'true'), concat(parameters.ExtraOptions, ' --tail-call-interp'), parameters.ExtraOptions) }}

can do the trick as well?

[zooba]

Okay, it looks like the image isn't available for Azure Pipelines yet: actions/runner-images#13638

Also worth noting that the plan in May when it comes out of beta is to just make it part of the windows-2025 image. So at that point, we'll get it without the vmImage name change.

[chris-eibl]

According to https://developercommunity.azure.com/t/11043750, I hoped it is already available, because it states "fixed". Reading the reactions then reveals it isn't :(

[zooba]

hoped it is already available, because it states "fixed".

Yeah, it's probably tied to internal bug systems, where "fixed" usually means "fix committed but deployment may not have run yet".