Use Clang for Windows (m68) (#1007)

* Switch to Clang for Win32
* Make sure to first dispose the native instance  
  In some cases, the native instance has callbacks into the managed world. This can be seen with the documents, they have a flush callback which requires that the managed objects all still exist. This is a valid situation where some object owns other managed objects. It is invalid to have some child object reference the parent object as there is no way of informing the child that it has no parent.

binding/Binding/SKObject.cs

@@ -307,13 +307,12 @@ namespace SkiaSharp
 			if (Interlocked.CompareExchange (ref isDisposed, 1, 0) != 0)
 				return;
 
-			if (disposing) {
-				DisposeManaged ();
-			}
-
 			if (Handle != IntPtr.Zero && OwnsHandle)
 				DisposeNative ();
 
+			if (disposing)
+				DisposeManaged ();
+
 			Handle = IntPtr.Zero;
 		}
 

build.cake

@@ -50,6 +50,7 @@ DirectoryPath NUGET_PACKAGES = EnvironmentVariable ("NUGET_PACKAGES") ?? PROFILE
 DirectoryPath ANDROID_SDK_ROOT = EnvironmentVariable ("ANDROID_SDK_ROOT") ?? EnvironmentVariable ("ANDROID_HOME") ?? PROFILE_PATH.Combine ("android-sdk");
 DirectoryPath ANDROID_NDK_HOME = EnvironmentVariable ("ANDROID_NDK_HOME") ?? EnvironmentVariable ("ANDROID_NDK_ROOT") ?? PROFILE_PATH.Combine ("android-ndk");
 DirectoryPath TIZEN_STUDIO_HOME = EnvironmentVariable ("TIZEN_STUDIO_HOME") ?? PROFILE_PATH.Combine ("tizen-studio");
+DirectoryPath LLVM_HOME = EnvironmentVariable ("LLVM_HOME") ?? "C:/Program Files/LLVM";
 
 DirectoryPath ROOT_PATH = MakeAbsolute(Directory("."));
 DirectoryPath DEPOT_PATH = MakeAbsolute(ROOT_PATH.Combine("externals/depot_tools"));
@@ -572,6 +573,7 @@ Information ("SDK Paths:");
 Information ("  Android SDK:   {0}", ANDROID_SDK_ROOT);
 Information ("  Android NDK:   {0}", ANDROID_NDK_HOME);
 Information ("  Tizen Studio:  {0}", TIZEN_STUDIO_HOME);
+Information ("  LLVM/Clang:    {0}", LLVM_HOME);
 Information ("");
 
 Information ("Environment Variables (whitelisted):");
@@ -582,7 +584,7 @@ var envVarsWhitelist = new [] {
     "node_label", "build_id", "git_sha", "git_branch_name",
     "feature_name", "msbuild_exe", "python_exe", "preview_label",
     "home", "userprofile", "nuget_packages", "build_arch",
-    "android_sdk_root", "android_ndk_root",
+    "android_sdk_root", "android_ndk_root", "llvm_home",
     "android_home", "android_ndk_home", "tizen_studio_home"
 };
 var envVars = EnvironmentVariables ();

cake/BuildExternals.cake

@@ -89,10 +89,13 @@ Task ("externals-windows")
             return;
         }
 
+        var clang = string.IsNullOrEmpty(LLVM_HOME.FullPath) ? "" : $"clang_win='{LLVM_HOME}' ";
+
         // generate native skia build files
         GnNinja ($"win/{arch}", "SkiaSharp",
             $"is_official_build=true skia_enable_tools=false " +
             $"target_os='win' target_cpu='{skiaArch}' " +
+            clang +
             $"skia_use_icu=false skia_use_sfntly=false skia_use_piex=true skia_use_dng_sdk=true " +
             $"skia_use_system_expat=false skia_use_system_libjpeg_turbo=false skia_use_system_libpng=false skia_use_system_libwebp=false skia_use_system_zlib=false " +
             $"extra_cflags=[ '-DSKIA_C_DLL', '/MT', '/EHsc', '/Z7' ] " +

scripts/azure-templates-bootstrapper.yml

@@ -73,6 +73,10 @@ jobs:
         - ${{ if contains(parameters.name, '_android_') }}:
           - pwsh: .\scripts\install-android-ndk.ps1
             displayName: Install the Android NDK
+        # install llvm
+        - ${{ if endsWith(parameters.name, '_windows') }}:
+          - pwsh: .\scripts\install-llvm.ps1
+            displayName: Install LLVM
       # install extra bits for the manged builds
       - ${{ if not(startsWith(parameters.name, 'native_')) }}:
         - task: UseDotNet@2
@@ -106,6 +110,7 @@ jobs:
         - pwsh: .\scripts\retry-command.ps1 -RetryCount ${{ parameters.retryCount }} { .\bootstrapper.ps1 -t ${{ parameters.target }} -v ${{ parameters.verbosity }} -c ${{ coalesce(parameters.configuration, 'Release') }} ${{ parameters.additionalArgs }} }
           env:
             JavaSdkDirectory: $(JAVA_HOME)
+            LLVM_HOME: $(LLVM_HOME)
           displayName: Run the bootstrapper for ${{ parameters.target }}
       - ${{ if not(endsWith(parameters.name, '_windows')) }}:
         - bash: ./scripts/retry-command.sh ${{ parameters.retryCount }} ./bootstrapper.sh -t ${{ parameters.target }} -v ${{ parameters.verbosity }} -c ${{ coalesce(parameters.configuration, 'Release') }} ${{ parameters.additionalArgs }}

scripts/install-llvm.ps1

@@ -0,0 +1,24 @@
+Param(
+    [string] $Version = "9.0.0"
+)
+
+$ErrorActionPreference = 'Stop'
+
+$url = "http://releases.llvm.org/${Version}/LLVM-${Version}-win64.exe"
+
+$llvmTemp = "$HOME/llvm-temp"
+$install = "$llvmTemp/llvm.exe"
+
+# download
+Write-Host "Downloading LLVM..."
+New-Item -ItemType Directory -Force -Path "$llvmTemp" | Out-Null
+(New-Object System.Net.WebClient).DownloadFile("$url", "$install")
+
+# install
+Write-Host "Installing LLVM..."
+& $install /S
+
+# make sure that LLVM is in LLVM_HOME
+Write-Host "##vso[task.setvariable variable=LLVM_HOME;]C:\Program Files\LLVM";
+
+exit $LASTEXITCODE

tests/SkiaSharp.Desktop.Tests/SkiaSharp.Desktop.Tests.csproj

@@ -112,7 +112,9 @@
   </ItemGroup>
   <ItemGroup>
     <Content Include="..\..\output\native\windows\$(Platform)\libSkiaSharp.dll" CopyToOutputDirectory="Always" Condition=" '$(IsWindows)' == 'true' " />
+    <Content Include="..\..\output\native\windows\$(Platform)\libSkiaSharp.pdb" CopyToOutputDirectory="Always" Condition=" '$(IsWindows)' == 'true' " />
     <Content Include="..\..\output\native\windows\$(Platform)\libHarfBuzzSharp.dll" CopyToOutputDirectory="Always" Condition=" '$(IsWindows)' == 'true' " />
+    <Content Include="..\..\output\native\windows\$(Platform)\libHarfBuzzSharp.pdb" CopyToOutputDirectory="Always" Condition=" '$(IsWindows)' == 'true' " />
     <Content Include="..\..\output\native\osx\libSkiaSharp.dylib" CopyToOutputDirectory="Always" Condition=" '$(IsMacOS)' == 'true' " />
     <Content Include="..\..\output\native\osx\libHarfBuzzSharp.dylib" CopyToOutputDirectory="Always" Condition=" '$(IsMacOS)' == 'true' " />
     <Content Include="..\..\output\native\linux\$(Platform)\libSkiaSharp.so" CopyToOutputDirectory="Always" Condition=" '$(IsLinux)' == 'true' " />