codex/.github/actions/setup-msvc-env/action.yml

name: setup-msvc-env
description: Expose an MSVC developer environment for the requested Windows target.
inputs:
  target:
    description: Rust target triple that will be built on this Windows runner.
    required: true
  host-arch:
    description: Optional Visual Studio host architecture override.
    required: false
    default: ""

runs:
  using: composite
  steps:
    - name: Expose MSVC SDK environment
      shell: pwsh
      run: |
        switch ("${{ inputs.target }}") {
          "x86_64-pc-windows-msvc" {
            $targetArch = "x64"
            $requiredComponent = "Microsoft.VisualStudio.Component.VC.Tools.x86.x64"
          }
          "aarch64-pc-windows-msvc" {
            $targetArch = "arm64"
            $requiredComponent = "Microsoft.VisualStudio.Component.VC.Tools.ARM64"
          }
          default {
            throw "Unsupported Windows MSVC target: ${{ inputs.target }}"
          }
        }

        $hostArch = "${{ inputs.host-arch }}"
        if (-not $hostArch) {
          $hostArch = if ($env:PROCESSOR_ARCHITEW6432 -eq "ARM64" -or $env:PROCESSOR_ARCHITECTURE -eq "ARM64") {
            "arm64"
          } else {
            "x64"
          }
        }

        $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
        if (-not (Test-Path $vswhere)) {
          throw "vswhere.exe not found"
        }

        $installPath = & $vswhere -latest -products * -requires $requiredComponent -property installationPath 2>$null
        if (-not $installPath) {
          throw "Could not locate a Visual Studio installation with component $requiredComponent"
        }

        $vsDevCmd = Join-Path $installPath "Common7\Tools\VsDevCmd.bat"
        if (-not (Test-Path $vsDevCmd)) {
          throw "VsDevCmd.bat not found at $vsDevCmd"
        }

        $varsToExport = @(
          "INCLUDE",
          "LIB",
          "LIBPATH",
          "PATH",
          "UCRTVersion",
          "UniversalCRTSdkDir",
          "VCINSTALLDIR",
          "VCToolsInstallDir",
          "WindowsLibPath",
          "WindowsSdkBinPath",
          "WindowsSdkDir",
          "WindowsSDKLibVersion",
          "WindowsSDKVersion"
        )

        $envLines = & cmd.exe /c ('"{0}" -no_logo -arch={1} -host_arch={2} >nul && set' -f $vsDevCmd, $targetArch, $hostArch)
        $vcToolsInstallDir = $null
        foreach ($line in $envLines) {
          if ($line -notmatch "^(.*?)=(.*)$") {
            continue
          }

          $name = $matches[1]
          $value = $matches[2]
          if ($varsToExport -contains $name) {
            if ($name -ieq "Path") {
              $name = "PATH"
            }
            if ($name -eq "VCToolsInstallDir") {
              $vcToolsInstallDir = $value
            }
            "$name=$value" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
          }
        }

        if (-not $vcToolsInstallDir) {
          throw "VCToolsInstallDir was not exported by VsDevCmd.bat"
        }

        $linker = $null
        $rustc = Get-Command rustc -ErrorAction SilentlyContinue
        if ($rustc) {
          $sysroot = (& rustc --print sysroot 2>$null).Trim()
          if ($sysroot) {
            $rustLld = Join-Path $sysroot "lib\rustlib\x86_64-pc-windows-msvc\bin\rust-lld.exe"
            if (Test-Path $rustLld) {
              $linker = $rustLld
            }
          }
        }
        if (-not $linker) {
          $linker = Join-Path $installPath "VC\Tools\Llvm\x64\bin\lld-link.exe"
        }
        if (-not (Test-Path $linker)) {
          $linker = Join-Path $vcToolsInstallDir "bin\Host${hostArch}\${targetArch}\link.exe"
        }
        if (-not (Test-Path $linker)) {
          throw "Windows linker not found at $linker"
        }

        if ((Split-Path -Leaf $linker) -match "lld") {
          $wrapperDir = Join-Path $env:RUNNER_TEMP "arm64-archive-lld-wrapper"
          New-Item -Path $wrapperDir -ItemType Directory -Force | Out-Null
          $wrapperPath = Join-Path $wrapperDir "lld-link-wrapper.exe"
          $wrapperSource = @'
using System;
using System.Diagnostics;

internal static class Program
{
    private static int Main(string[] args)
    {
        var linker = Environment.GetEnvironmentVariable("ARM64_ARCHIVE_REAL_LINKER");
        if (string.IsNullOrEmpty(linker))
        {
            Console.Error.WriteLine("ARM64_ARCHIVE_REAL_LINKER is not set");
            return 1;
        }

        var startInfo = new ProcessStartInfo(linker)
        {
            UseShellExecute = false,
        };
        foreach (var arg in args)
        {
            if (!string.Equals(arg, "/arm64hazardfree", StringComparison.OrdinalIgnoreCase))
            {
                startInfo.ArgumentList.Add(arg);
            }
        }

        using var process = Process.Start(startInfo);
        if (process is null)
        {
            Console.Error.WriteLine($"Failed to start linker: {linker}");
            return 1;
        }

        process.WaitForExit();
        return process.ExitCode;
    }
}
'@
          Add-Type -TypeDefinition $wrapperSource -Language CSharp -OutputAssembly $wrapperPath -OutputType ConsoleApplication
          "ARM64_ARCHIVE_REAL_LINKER=$linker" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
          $linker = $wrapperPath
        }

        Write-Output "Using Windows linker: $linker"
        $cargoTarget = "${{ inputs.target }}".ToUpperInvariant().Replace("-", "_")
        "CARGO_TARGET_${cargoTarget}_LINKER=$linker" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append