support optionally building AMD64 with tailcalling

Author: chris-eibl

windows-release/azure-pipelines.yml

@@ -42,6 +42,10 @@ parameters:
   displayName: "Signature description"
   type: string
   default: '(default)'
+- name: DoTailcalling
+  displayName: "Build AMD64 with tailcalling support (3.15 and later)"
+  type: boolean
+  default: false
 - name: DoJIT
   displayName: "Build the JIT compiler (3.14 and later)"
   type: boolean
@@ -161,7 +165,7 @@ stages:
   - stage: Build
     displayName: Build binaries
     pool:
-      vmImage: ${{ parameters.vmImage }}
+      vmImage: ${{ if eq(parameters.DoTailcalling, 'true') }} 'windows-2025-vs2026' ${{ else }} ${{ parameters.vmImage }}
     jobs:
     - template: start-arm64vm.yml
       parameters:

windows-release/stage-build.yml

@@ -4,6 +4,7 @@ parameters:
   DoPGOARM64: true
   DoFreethreaded: false
   ToBeSigned: false
+  DoTailcalling: false
   ExtraOptions: ''
   ExtraOptionsFreethreaded: '--disable-gil'
 
@@ -71,7 +72,7 @@ jobs:
           Platform: x64
           Configuration: Release
           _HostPython: .\python
-          ExtraOptions: ${{ parameters.ExtraOptions }}
+          ExtraOptions: ${{ parameters.ExtraOptions }}${{ if eq(parameters.DoTailcalling, 'true') }} ' --tail-call-interp'
           ${{ if eq(parameters.ToBeSigned, 'true') }}:
             Artifact: unsigned_amd64
           ${{ else }}:
@@ -131,7 +132,7 @@ jobs:
             Platform: x64
             Configuration: Release
             _HostPython: .\python
-            ExtraOptions: ${{ parameters.ExtraOptionsFreethreaded }}
+            ExtraOptions: ${{ parameters.ExtraOptionsFreethreaded }}${{ if eq(parameters.DoTailcalling, 'true') }} ' --tail-call-interp'
             ${{ if eq(parameters.ToBeSigned, 'true') }}:
               Artifact: unsigned_amd64_t
             ${{ else }}:
@@ -185,7 +186,7 @@ jobs:
           Platform: x64
           _HostPython: .\python
           PythonExePattern: python.exe
-          ExtraOptions: ${{ parameters.ExtraOptions }}
+          ExtraOptions: ${{ parameters.ExtraOptions }}${{ if eq(parameters.DoTailcalling, 'true') }} ' --tail-call-interp'
           ${{ if eq(parameters.ToBeSigned, 'true') }}:
             Artifact: unsigned_amd64
           ${{ else }}:
@@ -197,7 +198,7 @@ jobs:
             Platform: x64
             _HostPython: .\python
             PythonExePattern: python3*t.exe
-            ExtraOptions: ${{ parameters.ExtraOptionsFreethreaded }}
+            ExtraOptions: ${{ parameters.ExtraOptionsFreethreaded }}${{ if eq(parameters.DoTailcalling, 'true') }} ' --tail-call-interp'
             ${{ if eq(parameters.ToBeSigned, 'true') }}:
               Artifact: unsigned_amd64_t
             ${{ else }}: