Add Windows ARM64 CPU support for TorchSharp

Directory.Build.props

@@ -55,10 +55,12 @@
     <TargetPlatform Condition="'$(TargetPlatform)' == ''">$(TargetOS)-$(TargetArchitecture)</TargetPlatform>
 
     <TargetRuntimeID Condition="'$(TargetOS)' == 'windows'">win-x64</TargetRuntimeID>
+    <TargetRuntimeID Condition="'$(TargetPlatform)' == 'windows-arm64'">win-arm64</TargetRuntimeID>
     <TargetRuntimeID Condition="'$(TargetOS)' == 'linux'">linux-x64</TargetRuntimeID>
     <TargetRuntimeID Condition="'$(TargetPlatform)' == 'mac-arm64'">osx-arm64</TargetRuntimeID>
 
     <TargetRuntimeID Condition="'$(TargetOS)' == 'windows'">win-x64</TargetRuntimeID>
+    <TargetRuntimeID Condition="'$(TargetPlatform)' == 'windows-arm64'">win-arm64</TargetRuntimeID>
     <TargetRuntimeID Condition="'$(TargetOS)' == 'linux'">linux-x64</TargetRuntimeID>
     <TargetRuntimeID Condition="'$(TargetOS)' == 'mac'">osx-$(TargetArchitecture)</TargetRuntimeID>
 
@@ -141,14 +143,17 @@
     <LibTorchCpuLocalNameSuffix>cpu</LibTorchCpuLocalNameSuffix>
     <LibTorchCudaLocalNameSuffix>cu$(CudaVersionNoDot)</LibTorchCudaLocalNameSuffix>
     <LibTorchArchiveCoreName Condition="'$(TargetOS)' == 'windows'">libtorch-win-shared-with-deps$(LibTorchDebug)</LibTorchArchiveCoreName>
+    <LibTorchArchiveCoreName Condition="'$(TargetPlatform)' == 'windows-arm64'">libtorch-win-arm64-shared-with-deps$(LibTorchDebug)</LibTorchArchiveCoreName>
     <LibTorchArchiveCoreName Condition="'$(TargetOS)' == 'linux'">libtorch-shared-with-deps</LibTorchArchiveCoreName>
     <LibTorchArchiveCoreName Condition="'$(TargetOS)' == 'mac'">libtorch-macos-x86_64</LibTorchArchiveCoreName>
     <LibTorchArchiveCoreName Condition="'$(TargetPlatform)' == 'mac-arm64'">libtorch-macos-arm64</LibTorchArchiveCoreName>
     <LibTorchCpuArchiveBase>$(LibTorchArchiveCoreName)-$(LibTorchVersion)$(LibTorchCpuArchiveNameSuffix)</LibTorchCpuArchiveBase>
     <LibTorchCudaArchiveBase>$(LibTorchArchiveCoreName)-$(LibTorchVersion)$(LibTorchCudaArchiveNameSuffix)</LibTorchCudaArchiveBase>
     <LibTorchCpuLocalBase>$(LibTorchArchiveCoreName)-$(LibTorchVersion)$(LibTorchCpuLocalNameSuffix)</LibTorchCpuLocalBase>
     <LibTorchCudaLocalBase>$(LibTorchArchiveCoreName)-$(LibTorchVersion)$(LibTorchCudaLocalNameSuffix)</LibTorchCudaLocalBase>
-    <LibTorchCmakePath>$(IntermediateOutputRootPath)libtorch-cpu\$(LibTorchCpuLocalBase)\libtorch\share\cmake\Torch</LibTorchCmakePath>
+    <LibTorchCmakePath Condition="'$(TargetPlatform)' != 'windows-arm64'">$(IntermediateOutputRootPath)libtorch-cpu\$(LibTorchCpuLocalBase)\libtorch\share\cmake\Torch</LibTorchCmakePath>
+    <!-- Windows ARM64 archive has a different layout: share/cmake/Torch instead of libtorch/share/cmake/Torch -->
+    <LibTorchCmakePath Condition="'$(TargetPlatform)' == 'windows-arm64'">$(IntermediateOutputRootPath)libtorch-cpu\$(LibTorchCpuLocalBase)\share\cmake\Torch</LibTorchCmakePath>
   </PropertyGroup>
 
   <!-- Language configuration -->

Directory.Build.targets

@@ -18,6 +18,16 @@
     <NativeAssemblyReference Include="uv" />
   </ItemGroup>
 
+  <!-- Windows ARM64 CPU libtorch binary list used for examples and testing -->
+  <ItemGroup Condition="'$(NativeTargetArchitecture)' == 'arm64' and '$(OS)' == 'Windows_NT' and '$(TestUsesLibTorch)' == 'true' and ('$(TestCuda)' != 'true' or '$(SkipCuda)' == 'true') and '$(SkipNative)' != 'true' ">
+    <NativeAssemblyReference Include="armpl_lp64" />
+    <NativeAssemblyReference Include="c10" />
+    <NativeAssemblyReference Include="torch" />
+    <NativeAssemblyReference Include="torch_cpu" />
+    <NativeAssemblyReference Include="torch_global_deps" />
+    <NativeAssemblyReference Include="uv" />
+  </ItemGroup>
+
   <!-- Windows CUDA 12.1 libtorch binary list used for examples and testing -->
   <ItemGroup Condition="'$(NativeTargetArchitecture)' == 'x64' and '$(OS)' == 'Windows_NT' and '$(TestUsesLibTorch)' == 'true' and ('$(TestCuda)' == 'true' and '$(SkipCuda)' != 'true') and '$(SkipNative)' != 'true' ">
     <NativeAssemblyReference Include="c10" Variant="cuda\" />

azure-pipelines.yml

@@ -89,6 +89,15 @@ jobs:
     pool:
       vmImage: 'macos-latest'
 
+- template: /build/ci/job-template.yml
+  parameters:
+    prepScript: echo "no prep needed"
+    name: Windows_arm64
+    buildScript: dotnet build /p:SkipCuda=true /p:TargetArchitecture=arm64 /p:SkipNetFxBuild=true -c
+    testScript: echo "Cannot run ARM64 tests on x64 Azure Pipelines agent"
+    pool:
+      vmImage: 'windows-latest'
+
 ################################################################################
 # {Build} --> combine --> package to build native bits on multiple OS's
 ################################################################################
@@ -285,13 +294,72 @@ jobs:
   - publish: $(Build.SourcesDirectory)/bin/obj/packprep/$(BuildConfig)
     artifact: MacAssets_arm64
 
+################################################################################
+- job: Windows_arm64_Native_Build_For_Packages
+################################################################################
+  condition: and(ne(variables['system.pullrequest.isfork'], true), eq(variables['build.sourcebranchname'], '${{ parameters.SourceBranchName }}'))
+  variables:
+    BuildConfig: Release
+    OfficialBuildId: $(BUILD.BUILDNUMBER)
+    DOTNET_CLI_TELEMETRY_OPTOUT: 1
+    DOTNET_SKIP_FIRST_TIME_EXPERIENCE: 1
+    DOTNET_MULTILEVEL_LOOKUP: 0
+  pool:
+    vmImage: 'windows-latest'
+  steps:
+  # Initial cleanup
+  - script: |
+      rmdir /s /q .git 2>nul
+      dotnet nuget locals all --clear
+      dir
+    displayName: Initial cleanup
+    continueOnError: true
+
+  - task: UseDotNet@2
+    displayName: 'Use .NET Core sdk'
+    inputs:
+      packageType: sdk
+      version: 8.0.x
+      installationPath: $(Agent.ToolsDirectory)/dotnet
+
+  # Download ARM64 LibTorch and clean immediately
+  - script: |
+      dotnet build -c $(BuildConfig) src/Redist/libtorch-cpu/libtorch-cpu.proj /p:UpdateSHA=true /p:SkipTests=true /p:TargetOS=windows /p:TargetArchitecture=arm64 /t:Build /p:IncludeLibTorchCpuPackages=true
+      del /s /q *.zip 2>nul
+      del /s /q *.tar.gz 2>nul
+    displayName: Download ARM64 libtorch native binaries and cleanup
+    condition: eq('${{ parameters.BuildLibTorchPackages }}', true)
+
+  # Cross-compile LibTorchSharp for ARM64 on x64 host
+  - script: dotnet build -c $(BuildConfig) src/TorchSharp/TorchSharp.csproj /p:SkipCuda=true /p:SkipTests=true /p:TargetArchitecture=arm64
+    condition: eq('${{ parameters.BuildLibTorchPackages }}', true)
+    displayName: Build TorchSharp win-arm64
+
+  - script: dotnet build -c $(BuildConfig) src/TorchVision/TorchVision.csproj /p:SkipCuda=true /p:SkipTests=true /p:TargetArchitecture=arm64
+    displayName: Build TorchVision
+
+  - script: dotnet build -c $(BuildConfig) src/TorchAudio/TorchAudio.csproj /p:SkipCuda=true /p:SkipTests=true /p:TargetArchitecture=arm64
+    displayName: Build TorchAudio
+
+  # Clean up unnecessary files before publishing
+  - script: |
+      del /s /q $(Build.SourcesDirectory)\bin\*.pdb 2>nul
+      del /s /q $(Build.SourcesDirectory)\bin\*.xml 2>nul
+      del /s /q $(Build.SourcesDirectory)\bin\obj\packprep\$(BuildConfig)\*.lib 2>nul
+    displayName: Clean up unnecessary files
+    continueOnError: true
+
+  - publish: $(Build.SourcesDirectory)/bin/obj/packprep/$(BuildConfig)
+    artifact: WindowsAssets_arm64
+
 ################################################################################
 - job: Build_TorchSharp_And_libtorch_cpu_Packages
 ################################################################################
   condition: and(ne(variables['system.pullrequest.isfork'], true), eq(variables['build.sourcebranchname'], '${{ parameters.SourceBranchName }}'))
   dependsOn:
   - Linux_Native_Build_For_Packages
   - Windows_Native_Build_For_Packages
+  - Windows_arm64_Native_Build_For_Packages
   - MacOS_arm64_Native_Build_For_Packages
   timeoutInMinutes: 90
   variables:
@@ -496,6 +564,56 @@ jobs:
     displayName: Clean WindowsAssets immediately
     continueOnError: true
 
+  # Process Windows ARM64 assets
+  - task: DownloadPipelineArtifact@2
+    displayName: Download Windows ARM64 TorchSharp assets
+    inputs:
+      artifact: WindowsAssets_arm64
+      patterns: |
+        TorchSharp/**
+      path: $(Pipeline.Workspace)/WindowsAssets_arm64
+    retryCountOnTaskFailure: 3
+
+  - task: DownloadPipelineArtifact@2
+    displayName: Download Windows ARM64 TorchAudio assets
+    inputs:
+      artifact: WindowsAssets_arm64
+      patterns: |
+        TorchAudio/**
+      path: $(Pipeline.Workspace)/WindowsAssets_arm64
+    retryCountOnTaskFailure: 3
+
+  - task: DownloadPipelineArtifact@2
+    displayName: Download Windows ARM64 TorchVision assets
+    inputs:
+      artifact: WindowsAssets_arm64
+      patterns: |
+        TorchVision/**
+      path: $(Pipeline.Workspace)/WindowsAssets_arm64
+    retryCountOnTaskFailure: 3
+
+  - task: DownloadPipelineArtifact@2
+    displayName: Download Windows ARM64 libtorch-cpu assets
+    condition: eq('${{ parameters.BuildLibTorchPackages }}', true)
+    inputs:
+      artifact: WindowsAssets_arm64
+      patterns: |
+        libtorch-cpu-win-arm64/**
+      path: $(Pipeline.Workspace)/WindowsAssets_arm64
+    retryCountOnTaskFailure: 3
+    continueOnError: true
+
+  - task: CopyFiles@2
+    displayName: Copy Windows ARM64 native assets (batch)
+    inputs:
+      sourceFolder: $(Pipeline.Workspace)/WindowsAssets_arm64
+      targetFolder: $(Build.SourcesDirectory)/bin/obj/packprep/$(BuildConfig)
+      cleanTargetFolder: false
+
+  - script: rmdir /s /q $(Pipeline.Workspace)\WindowsAssets_arm64
+    displayName: Clean WindowsAssets_arm64 immediately
+    continueOnError: true
+
   # Restore and pack
   - script: dotnet restore pkg/pack.proj /p:Configuration=Release --nologo
     displayName: Restore package projects

pkg/libtorch-cpu-win-arm64/libtorch-cpu-win-arm64.nupkgproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk" DefaultTargets="Pack">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="..\common\CpuHeadPackage.props" Pack="true" PackagePath="buildTransitive\netstandard2.0\$(MSBuildProjectName).props" />
+    <Content Include="..\common\CpuHeadPackage.targets" Pack="true" PackagePath="buildTransitive\netstandard2.0\$(MSBuildProjectName).targets" />
+    <Content Include="..\empty.txt" Pack="true" PackagePath="lib\netstandard2.0\_._" />
+    <Content Include="$(RepoRoot)\THIRD-PARTY-NOTICES.txt" Pack="true" PackagePath="LICENSE-LIBTORCH.txt" />
+  </ItemGroup>
+</Project>

pkg/libtorch-cpu/libtorch-cpu.nupkgproj

@@ -7,6 +7,7 @@
   <ItemGroup>
      <ProjectReference Include="../libtorch-cpu-linux-x64/libtorch-cpu-linux-x64.nupkgproj" />
      <ProjectReference Include="../libtorch-cpu-osx-arm64/libtorch-cpu-osx-arm64.nupkgproj" />
+     <ProjectReference Include="../libtorch-cpu-win-arm64/libtorch-cpu-win-arm64.nupkgproj" />
      <ProjectReference Include="../libtorch-cpu-win-x64/libtorch-cpu-win-x64.nupkgproj" />
   </ItemGroup>
 

pkg/pack.proj

@@ -24,6 +24,8 @@
              Condition="'$(IncludeTorchSharpPackage)' == 'true' AND !Exists('$(PackagePreparationPath)\TorchSharp\runtimes\linux-x64\native\libLibTorchSharp.so')" />
     <Warning Text="Packages will be incomplete and unusable on win-x64 platform. To get a complete package you need the LibTorchSharp.dll binaries for other platforms and copy them into '$(PackagePreparationPath)' to make complete packages. This is automated by Azure Pipelines."
              Condition="'$(IncludeTorchSharpPackage)' == 'true' AND !Exists('$(PackagePreparationPath)\TorchSharp\runtimes\win-x64\native\LibTorchSharp.dll')" />
+    <Warning Text="Packages will be incomplete and unusable on win-arm64 platform. To get a complete package you need the LibTorchSharp.dll binaries for other platforms and copy them into '$(PackagePreparationPath)' to make complete packages. This is automated by Azure Pipelines."
+             Condition="'$(IncludeTorchSharpPackage)' == 'true' AND !Exists('$(PackagePreparationPath)\TorchSharp\runtimes\win-arm64\native\LibTorchSharp.dll')" />
 
     <MSBuild Projects="%(PackProject.Identity)" Targets="Pack" />
 

src/Native/build.cmd

@@ -23,6 +23,7 @@ if /i [%1] == [Debug]       ( set CMAKE_BUILD_TYPE=Debug&&shift&goto Arg_Loop)
 if /i [%1] == [x86]         ( set __BuildArch=x86&&set __VCBuildArch=x86&&shift&goto Arg_Loop)
 if /i [%1] == [x64]         ( set __BuildArch=x64&&set __VCBuildArch=x86_amd64&&shift&goto Arg_Loop)
 if /i [%1] == [amd64]       ( set __BuildArch=x64&&set __VCBuildArch=x86_amd64&&shift&goto Arg_Loop)
+if /i [%1] == [arm64]       ( set __BuildArch=ARM64&&set __VCBuildArch=amd64_arm64&&shift&goto Arg_Loop)
 
 if /i [%1] == [--libtorchpath] ( set LIBTORCH_PATH=%2&&shift&goto Arg_Loop)
 
@@ -66,50 +67,39 @@ exit /b 1
 :: Setup vars for VS2026
 set __PlatformToolset=v145
 set __VSVersion=18 2026
-if NOT "%__BuildArch%" == "arm64" (
-    :: Set the environment for the native build
-    call "%VS180COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
-)
+:: Set the environment for the native build (including cross-compilation for ARM64)
+call "%VS180COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
 goto :SetupDirs
 
 :VS2022
 :: Setup vars for VS2022
 set __PlatformToolset=v143
 set __VSVersion=17 2022
-if NOT "%__BuildArch%" == "arm64" (
-    :: Set the environment for the native build
-    call "%VS170COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
-)
+:: Set the environment for the native build (including cross-compilation for ARM64)
+call "%VS170COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
 goto :SetupDirs
 
 :VS2019
 :: Setup vars for VS2019
 set __PlatformToolset=v142
 set __VSVersion=16 2019
-if NOT "%__BuildArch%" == "arm64" (
-    :: Set the environment for the native build
-    call "%VS160COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
-)
+:: Set the environment for the native build (including cross-compilation for ARM64)
+call "%VS160COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
 goto :SetupDirs
 
 :VS2017
 :: Setup vars for VS2017
 set __PlatformToolset=v141
 set __VSVersion=15 2017
-if NOT "%__BuildArch%" == "arm64" (
-    :: Set the environment for the native build
-    call "%VS150COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
-)
+:: Set the environment for the native build (including cross-compilation for ARM64)
+call "%VS150COMNTOOLS%..\..\VC\Auxiliary\Build\vcvarsall.bat" %__VCBuildArch%
 goto :SetupDirs
 
 :VS2015
 :: Setup vars for VS2015build
 set __PlatformToolset=v140
 set __VSVersion=14 2015
-if NOT "%__BuildArch%" == "arm64" (
-    :: Set the environment for the native build
-    call "%VS140COMNTOOLS%..\..\VC\vcvarsall.bat" %__VCBuildArch%
-)
+call "%VS140COMNTOOLS%..\..\VC\vcvarsall.bat" %__VCBuildArch%
 
 :SetupDirs
 :: Setup to cmake the native components

src/Native/gen-buildsys-win.bat

@@ -30,6 +30,7 @@ popd
 :: Set the target architecture to a format cmake understands.
 if /i "%3" == "x64"     (set __ExtraCmakeParams=%__ExtraCmakeParams% -A x64)
 if /i "%3" == "x86"     (set __ExtraCmakeParams=%__ExtraCmakeParams% -A Win32)
+if /i "%3" == "ARM64"   (set __ExtraCmakeParams=%__ExtraCmakeParams% -A ARM64)
 
 echo "%CMakePath%" "-DCMAKE_BUILD_TYPE=%CMAKE_BUILD_TYPE%" "-DCMAKE_INSTALL_PREFIX=%__CMakeBinDir%" "-DLIBTORCH_PATH=%LIBTORCH_PATH%" -G "Visual Studio %__VSString%" %__ExtraCmakeParams% -B. -H%1
 "%CMakePath%" "-DCMAKE_BUILD_TYPE=%CMAKE_BUILD_TYPE%" "-DCMAKE_INSTALL_PREFIX=%__CMakeBinDir%" "-DLIBTORCH_PATH=%LIBTORCH_PATH%" -G "Visual Studio %__VSString%" %__ExtraCmakeParams% -B. -H%1
@@ -40,7 +41,7 @@ GOTO :DONE
   echo "Usage..."
   echo "gen-buildsys-win.bat <VSVersion> <Target Architecture>"
   echo "Specify the VSVersion to be used - VS2015, VS2017 or VS2019"
-  echo "Specify the Target Architecture - x86, or x64."
+  echo "Specify the Target Architecture - x86, x64, or ARM64."
   EXIT /B 1
 
 :DONE

src/Redist/libtorch-cpu/libtorch-cpu.proj

@@ -30,7 +30,7 @@
     <CopyToPackageSemaphore>$(MainPackageFolder)\.copied.SkipTests.$(SkipTests).IncludeLibTorchCpuPackages.$(IncludeLibTorchCpuPackages)</CopyToPackageSemaphore>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(TargetOS)' == 'windows'">
+  <ItemGroup Condition="'$(TargetOS)' == 'windows' and '$(NativeTargetArchitecture)' != 'arm64'">
     <File Include="libtorch\lib\c10.dll" />
     <File Include="libtorch\lib\libiomp5md.dll" />
     <File Include="libtorch\lib\libiompstubs5md.dll" />
@@ -39,6 +39,15 @@
     <File Include="libtorch\lib\torch_global_deps.dll" />
     <File Include="libtorch\lib\uv.dll" />
   </ItemGroup>
+  <!-- Windows ARM64 archive has a different layout (lib/ instead of libtorch/lib/) and uses ARM Performance Libraries instead of Intel OpenMP -->
+  <ItemGroup Condition="'$(TargetOS)' == 'windows' and '$(NativeTargetArchitecture)' == 'arm64'">
+    <File Include="lib\armpl_lp64.dll" />
+    <File Include="lib\c10.dll" />
+    <File Include="lib\torch.dll" />
+    <File Include="lib\torch_cpu.dll" />
+    <File Include="lib\torch_global_deps.dll" />
+    <File Include="lib\uv.dll" />
+  </ItemGroup>
   <ItemGroup Condition="'$(NativeTargetArchitecture)' == 'arm64' and '$(TargetOS)' == 'mac'">
     <File Include="libtorch\lib\libc10.dylib" />
     <File Include="libtorch\lib\libshm.dylib" />

src/Redist/libtorch-cpu/libtorch-win-arm64-shared-with-deps-2.10.0%2Bcpu.zip.sha

@@ -0,0 +1 @@
+38d666a9030ba098d1ac5dabfd995cf3d113a12d512252080978b0cc206af205

src/TorchSharp/Torch.cs

@@ -38,7 +38,8 @@ public static partial class torch
             RuntimeInformation.OSArchitecture == Architecture.Arm64;
 
         static string nativeRid =>
-            RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? $"win-x64" :
+            RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+                ? (RuntimeInformation.OSArchitecture == Architecture.Arm64 ? "win-arm64" : "win-x64") :
             RuntimeInformation.IsOSPlatform(OSPlatform.Linux) ? $"linux-x64" :
             isAppleSilicon ? "osx-arm64" :
             "any";