windows: support independent MSVC and MinGW profiles (R9, depends on goplus/lib#26)

.github/actions/setup-demo-deps/action.yml

@@ -1,14 +1,27 @@
 name: "Setup Demo Dependencies"
 description: "Install dependencies required by the LLGo demo suite"
+inputs:
+  windows-abi:
+    description: "Native Windows toolchain profile: msvc or mingw"
+    required: false
+    default: "msvc"
 
 runs:
   using: "composite"
   steps:
     - name: Set up Python 3.12 on Windows
       if: runner.os == 'Windows'
+      id: windows_python
       uses: actions/setup-python@v6
       with:
-        python-version: "3.12"
+        # LLVM 19.1.3's MSVC LLDB embeds the 3.12.7 hosted-tool-cache prefix.
+        # A newer 3.12 patch is ABI-compatible, but LLDB combines its embedded
+        # stdlib path with that installation and cannot import encodings. Keep
+        # the MinGW demo environment on the normal latest 3.12 patch.
+        python-version: ${{ inputs.windows-abi == 'msvc' && '3.12.7' || '3.12' }}
+        # setup-python otherwise replaces PKG_CONFIG_PATH, hiding the native
+        # vcpkg metadata installed by setup-deps from LLGo's runtime build.
+        update-environment: false
 
     - name: Install cargs demo library on Unix
       if: runner.os != 'Windows'
@@ -58,11 +71,23 @@ runs:
       run: |
         $ErrorActionPreference = "Stop"
 
-        $architecture = [System.Runtime.InteropServices.RuntimeInformation]::OSArchitecture
-        switch ($architecture) {
-          "X64" { $targetTriple = "x86_64-pc-windows-msvc" }
-          "Arm64" { $targetTriple = "aarch64-pc-windows-msvc" }
-          default { throw "Unsupported Windows architecture: $architecture" }
+        if ("${{ inputs.windows-abi }}" -notin @("msvc", "mingw")) {
+          throw "Unsupported Windows ABI profile: ${{ inputs.windows-abi }}"
+        }
+        $compiler = (Get-Command clang.exe).Source
+        $target = (& $compiler -dumpmachine).Trim()
+        if ("${{ inputs.windows-abi }}" -eq "msvc") {
+          if ($target -notmatch "-windows-msvc$") {
+            throw "The MSVC profile resolved Clang target $target"
+          }
+          $runtimeArgs = @("-fms-runtime-lib=dll")
+          $archive = "cargs.lib"
+        } else {
+          if ($target -notmatch "-(windows-gnu|mingw32)$") {
+            throw "The MinGW profile resolved Clang target $target"
+          }
+          $runtimeArgs = @()
+          $archive = "libcargs.a"
         }
 
         $libsDir = Join-Path $env:GITHUB_WORKSPACE "_demo\c\cargs\libs"
@@ -77,18 +102,22 @@ runs:
         Invoke-WebRequest "$baseUrl/src/cargs.c" -OutFile $source
 
         $object = Join-Path $env:RUNNER_TEMP "cargs.obj"
-        & $env:CC "--target=$targetTriple" -O2 -std=c11 `
+        & $compiler @runtimeArgs -O2 -std=c11 `
           "-I$includeDir" -c $source -o $object
         if ($LASTEXITCODE -ne 0) {
           throw "Compiling cargs failed with exit code $LASTEXITCODE"
         }
-        & llvm-lib "/out:$(Join-Path $libDir 'cargs.lib')" $object
+        if ("${{ inputs.windows-abi }}" -eq "msvc") {
+          & llvm-lib "/out:$(Join-Path $libDir $archive)" $object
+        } else {
+          & llvm-ar rcs (Join-Path $libDir $archive) $object
+        }
         if ($LASTEXITCODE -ne 0) {
           throw "Archiving cargs failed with exit code $LASTEXITCODE"
         }
 
-        # A static MSVC library avoids a demo-only DLL search path. pkgconf's
-        # logical -lcargs entry is resolved by LLGo's Windows dependency path.
+        # A static target-native library avoids a demo-only DLL search path.
+        # Each profile's pkg-config resolves -lcargs to its own archive format.
         # Windows pkgconf relocates a variable named "prefix" relative to the
         # .pc file by default. Keep these installation paths absolute because
         # the metadata intentionally lives under RUNNER_TEMP, not the library.
@@ -105,8 +134,6 @@ runs:
         Cflags: -I"`${includedir}"
         "@ | Set-Content -Encoding ascii (Join-Path $pcDir "cargs.pc")
 
-        Add-Content -Encoding utf8 $env:GITHUB_ENV "PKG_CONFIG_PATH=$pcDir;$env:PKG_CONFIG_PATH"
-
     - name: Install Python demo dependencies on Unix
       if: runner.os != 'Windows'
       shell: bash
@@ -129,19 +156,26 @@ runs:
       run: |
         $ErrorActionPreference = "Stop"
 
-        python -m pip install numpy torch
+        $python = "${{ steps.windows_python.outputs.python-path }}"
+        & $python -m pip install numpy torch
         if ($LASTEXITCODE -ne 0) {
           throw "Installing Python demo dependencies failed with exit code $LASTEXITCODE"
         }
 
-        $prefix = (& python -c "import sys; print(sys.base_prefix)").Trim()
-        $includeDir = (& python -c "import sysconfig; print(sysconfig.get_path('include'))").Trim()
-        $version = (& python -c "import sys; print(f'{sys.version_info.major}{sys.version_info.minor}')").Trim()
+        $prefix = (& $python -c "import sys; print(sys.base_prefix)").Trim()
+        $includeDir = (& $python -c "import sysconfig; print(sysconfig.get_path('include'))").Trim()
+        $version = (& $python -c "import sys; print(f'{sys.version_info.major}{sys.version_info.minor}')").Trim()
         $libDir = Join-Path $prefix "libs"
         $importLibrary = Join-Path $libDir "python$version.lib"
         if (-not (Test-Path $importLibrary)) {
           throw "Python import library was not found at $importLibrary"
         }
+        if ("${{ inputs.windows-abi }}" -eq "mingw") {
+          # LLVM's MinGW linker accepts the same COFF import-library contents
+          # but its -l search uses the GNU filename. Keep the official Python
+          # artifact untouched and expose only a profile-local spelling.
+          Copy-Item -Force $importLibrary (Join-Path $libDir "libpython$version.a")
+        }
 
         $pcDir = Join-Path $env:RUNNER_TEMP "llgo-pkgconfig"
         New-Item -ItemType Directory -Force $pcDir | Out-Null
@@ -157,3 +191,6 @@ runs:
         Libs: -L"`${libdir}" -lpython$version
         Cflags: -I"`${includedir}"
         "@ | Set-Content -Encoding ascii (Join-Path $pcDir "python3-embed.pc")
+
+        Add-Content -Encoding utf8 $env:GITHUB_PATH $prefix
+        Add-Content -Encoding utf8 $env:GITHUB_ENV "LLGO_WINDOWS_PYTHON_HOME=$prefix"