DRAFT: Add an aarch64-msvc build running on ARM64 Windows

Author: dpaoliello

.github/workflows/ci.yml

@@ -81,18 +81,23 @@ jobs:
         include: ${{ fromJSON(needs.calculate_matrix.outputs.jobs) }}
     steps:
       - if: contains(matrix.os, 'windows')
-        uses: msys2/setup-msys2@v2.22.0
+        uses: msys2/setup-msys2@v2.23.0
         with:
-          # i686 jobs use mingw32. x86_64 and cross-compile jobs use mingw64.
-          msystem: ${{ contains(matrix.name, 'i686') && 'mingw32' || 'mingw64' }}
+          # i686 jobs use mingw32.
+          # aarch64 runners use clangarm64.
+          # x86_64 and cross-compile jobs use mingw64.
+          msystem: ${{ contains(matrix.name, 'i686') && 'mingw32' || contains(matrix.os, 'arm64') && 'clangarm64' || 'mingw64' }}
           # don't try to download updates for already installed packages
           update: false
           # don't try to use the msys that comes built-in to the github runner,
           # so we can control what is installed (i.e. not python)
-          release: true
+          release: ${{ !contains(matrix.os, 'arm64') }}
           # Inherit the full path from the Windows environment, with MSYS2's */bin/
           # dirs placed in front. This lets us run Windows-native Python etc.
           path-type: inherit
+          # Workaround for https://github.com/msys2/setup-msys2/issues/358
+          # MSYS2 installer hangs on ARM64 Windows if caching is enabled.
+          cache: ${{ !contains(matrix.os, 'arm64') }}
           install: >
             make
             dos2unix

src/ci/github-actions/jobs.yml

@@ -32,6 +32,10 @@ runners:
     os: windows-2022-16core-64gb
     <<: *base-job
 
+  - &job-windows-aarch64
+    os: windows-11-arm64-8core-32gb
+    <<: *base-job
+
   - &job-aarch64-linux
     os: ubuntu-22.04-arm64-8core-32gb
 
@@ -80,17 +84,11 @@ envs:
 # These jobs automatically inherit envs.pr, to avoid repeating
 # it in each job definition.
 pr:
-  - image: mingw-check
-    <<: *job-linux-4c
-  - image: mingw-check-tidy
-    continue_on_error: true
-    <<: *job-linux-4c
-  - image: x86_64-gnu-llvm-17
+  - image: aarch64-msvc
     env:
-      ENABLE_GCC_CODEGEN: "1"
-    <<: *job-linux-16c
-  - image: x86_64-gnu-tools
-    <<: *job-linux-16c
+      RUST_CONFIGURE_ARGS: --build=aarch64-pc-windows-msvc
+      SCRIPT: make ci-msvc
+    <<: *job-windows-aarch64
 
 # Jobs that run when you perform a try build (@bors try)
 # These jobs automatically inherit envs.try, to avoid repeating