Support optionally building AMD64 with tailcalling (#346)

Author: chris-eibl

windows-release/azure-pipelines.yml

@@ -42,6 +42,10 @@ parameters:
   displayName: "Signature description"
   type: string
   default: '(default)'
+- name: DoTailCalling
+  displayName: "Build with tail-calling 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: ${{ iif(eq(parameters.DoTailCalling, 'true'), 'windows-2025-vs2026', parameters.vmImage) }}
     jobs:
     - template: start-arm64vm.yml
       parameters:
@@ -186,7 +190,10 @@ stages:
           ExtraOptionsFreethreaded: '--disable-gil --experimental-jit-off'
         ${{ else }}:
           ExtraOptionsFreethreaded: '--disable-gil --experimental-jit'
-
+        ${{ if ne(parameters.DoTailCalling, 'true') }}:
+          TailCallingOption: ''
+        ${{ else }}:
+          TailCallingOption: '--tail-call-interp'
   - stage: Sign
     displayName: Sign binaries
     dependsOn: Build

windows-release/stage-build.yml

@@ -6,6 +6,7 @@ parameters:
   ToBeSigned: false
   ExtraOptions: ''
   ExtraOptionsFreethreaded: '--disable-gil'
+  TailCallingOption: ''
 
 jobs:
 - job: Build_Docs
@@ -71,7 +72,7 @@ jobs:
           Platform: x64
           Configuration: Release
           _HostPython: .\python
-          ExtraOptions: ${{ parameters.ExtraOptions }}
+          ExtraOptions: ${{ parameters.ExtraOptions }} ${{ parameters.TailCallingOption }}
           ${{ 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 }} ${{ parameters.TailCallingOption }}
             ${{ 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 }} ${{ parameters.TailCallingOption }}
           ${{ 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 }} ${{ parameters.TailCallingOption }}
             ${{ if eq(parameters.ToBeSigned, 'true') }}:
               Artifact: unsigned_amd64_t
             ${{ else }}: