Windows: Use pre-installed CMake and Ninja

Teach build.ps1 to search for a pre-installed CMake and Ninja from the
PATH instead of only using one installed in Visual Studio. If one is not
installed or on the path, the script will attempt to use one installed
in Visual Studio. Preference is given to the executable found in the
path environment variable.

Author: etcwilde

utils/build.ps1

@@ -396,6 +396,31 @@ $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.e
 $VSInstallRoot = & $vswhere -nologo -latest -products "*" -all -prerelease -property installationPath
 $msbuild = "$VSInstallRoot\MSBuild\Current\Bin\$BuildArchName\MSBuild.exe"
 
+function Get-CMake {
+  try {
+    return (Get-Command "cmake.exe" -ErrorAction Stop).Source)
+  } catch {
+    if (Test-Path "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin") {
+      return "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin\cmake.exe"
+    }
+  }
+  throw "CMake not found on Path nor in the Visual Studio Installation. Please Install CMake to continue."
+}
+
+function Get-Ninja {
+  try {
+    return (Get-Command "Ninja.exe" -ErrorAction Stop).Source
+  } catch {
+      if (Test-Path "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja") {
+          return "${VSInstallRoot}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja\ninja.exe"
+      }
+  }
+  throw "Ninja not found on Path nor in the Visual Studio Installation. Please Install Ninja to continue."
+}
+
+$cmake = Get-CMake
+$ninja = Get-Ninja
+
 $NugetRoot = "$BinaryCache\nuget"
 $LibraryRoot = "$ImageRoot\Library"
 
@@ -1222,14 +1247,6 @@ function Build-CMakeProject {
     }
 
     if ($Platform.OS -eq [OS]::Android) {
-      $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
-      $VSInstallPath = & $vswhere -nologo -latest -products * -property installationPath
-      if (Test-Path "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin") {
-        $env:Path = "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin;${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja;${env:Path}"
-        Add-KeyValueIfNew $Defines CMAKE_MAKE_PROGRAM "${VSInstallPath}\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja\ninja.exe"
-      } else {
-        throw "Missing CMake and Ninja in the visual studio installation that are needed to build Android"
-      }
       $androidNDKPath = Get-AndroidNDKPath
       Add-KeyValueIfNew $Defines CMAKE_C_COMPILER (Join-Path -Path $androidNDKPath -ChildPath "toolchains\llvm\prebuilt\windows-x86_64\bin\clang.exe")
       Add-KeyValueIfNew $Defines CMAKE_CXX_COMPILER (Join-Path -Path $androidNDKPath -ChildPath "toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe")
@@ -1428,6 +1445,9 @@ function Build-CMakeProject {
       Add-KeyValueIfNew $Defines CMAKE_INSTALL_PREFIX $InstallTo
     }
 
+    $ninja_bin = Get-NinjaPath
+    Add-KeyValueIfNew $Defines CMAKE_MAKE_PROGRAM "$ninja"
+
     # Generate the project
     $cmakeGenerateArgs = @("-B", $Bin, "-S", $Src, "-G", $Generator)
     if ($CacheScript) {
@@ -1467,26 +1487,25 @@ function Build-CMakeProject {
     } elseif ($UsePinnedCompilers.Contains("Swift")) {
       $env:Path = "$(Get-PinnedToolchainRuntime);${env:Path}"
     }
-
     if ($ToBatch) {
       Write-Output ""
-      Write-Output "echo cmake.exe $cmakeGenerateArgs"
+      Write-Output "echo $cmake $cmakeGenerateArgs"
     } else {
-      Write-Host "cmake.exe $cmakeGenerateArgs"
+      Write-Host "$cmake $cmakeGenerateArgs"
     }
-    Invoke-Program cmake.exe @cmakeGenerateArgs
+    Invoke-Program $cmake @cmakeGenerateArgs
 
     # Build all requested targets
     foreach ($Target in $BuildTargets) {
       if ($Target -eq "default") {
-        Invoke-Program cmake.exe --build $Bin
+        Invoke-Program $cmake --build $Bin
       } else {
-        Invoke-Program cmake.exe --build $Bin --target $Target
+        Invoke-Program $cmake --build $Bin --target $Target
       }
     }
 
     if ($BuildTargets.Length -eq 0 -and $InstallTo) {
-      Invoke-Program cmake.exe --build $Bin --target install
+      Invoke-Program $cmake --build $Bin --target install
     }
   }
 
@@ -2270,7 +2289,7 @@ function Build-ExperimentalRuntime {
     Invoke-VsDevShell $BuildPlatform
 
     Push-Location "${SourceCache}\swift\Runtimes"
-    Start-Process -Wait -WindowStyle Hidden -FilePath cmake.exe -ArgumentList @("-P", "Resync.cmake")
+    Start-Process -Wait -WindowStyle Hidden -FilePath $cmake -ArgumentList @("-P", "Resync.cmake")
     Pop-Location
   }
 
@@ -2681,7 +2700,7 @@ function Test-LLBuild {
   # Build additional llvm executables needed by tests
   Invoke-IsolatingEnvVars {
     Invoke-VsDevShell $BuildPlatform
-    Invoke-Program ninja.exe -C (Get-ProjectBinaryCache $BuildPlatform BuildTools) FileCheck not
+    Invoke-Program $ninja -C (Get-ProjectBinaryCache $BuildPlatform BuildTools) FileCheck not
   }
 
   Invoke-IsolatingEnvVars {