dotnet · michaelgsharp · May 18, 2021 · Mar 3, 2021 · Apr 5, 2021 · May 4, 2021
diff --git a/.gitignore b/.gitignore
@@ -12,6 +12,7 @@
 *.user
 *.userosscache
 *.sln.docstates
+*.DS_Store
 
 # User-specific files (MonoDevelop/Xamarin Studio)
 *.userprefs
@@ -37,6 +38,9 @@ msbuild.binlog
 # Uncomment if you have tasks that create the project's static files in wwwroot
 #wwwroot/
 
+# VSCode files
+.vscode/
+
 # Visual Studio 2017 auto generated files
 Generated\ Files/
 

diff --git a/Directory.Build.props b/Directory.Build.props
@@ -23,8 +23,8 @@
     <Configuration Condition="'$(Configuration)'==''">Debug</Configuration>
     <Configurations>Debug;Release;Debug-netcoreapp3_1;Release-netcoreapp3_1;Debug-netfx;Release-netfx</Configurations>
     <Platform Condition="'$(Platform)'==''">AnyCPU</Platform>
-    <TargetArchitecture Condition="'$(TargetArchitecture)' == ''">x64</TargetArchitecture>
-    <NativeTargetArchitecture Condition="'$(NativeTargetArchitecture)' == ''">$(TargetArchitecture)</NativeTargetArchitecture>
+    <TargetArchitecture Condition="'$(TargetArchitecture)' == ''">$([System.Runtime.InteropServices.RuntimeInformation]::OSArchitecture)</TargetArchitecture>
+    <TargetArchitecture>$(TargetArchitecture.ToLower())</TargetArchitecture>
     <PlatformConfig>$(Platform).$(Configuration)</PlatformConfig>
     <StrongNameKeyId>Open</StrongNameKeyId>
   </PropertyGroup>

diff --git a/Directory.Build.targets b/Directory.Build.targets
@@ -8,27 +8,33 @@
 
   <Target Name="CopyNativeAssembiles" AfterTargets="CopyFilesToOutputDirectory">
     <PropertyGroup>
-		<LibPrefix Condition="'$(OS)' != 'Windows_NT'">lib</LibPrefix>
-		<LibExtension Condition="'$(OS)' == 'Windows_NT'">.dll</LibExtension>
-		<LibExtension Condition="'$(OS)' != 'Windows_NT'">.so</LibExtension>
-		<LibExtension Condition="$([MSBuild]::IsOSPlatform('osx'))">.dylib</LibExtension>
+      <LibPrefix Condition="'$(OS)' != 'Windows_NT'">lib</LibPrefix>
+      <LibExtension Condition="'$(OS)' == 'Windows_NT'">.dll</LibExtension>
+      <LibExtension Condition="'$(OS)' != 'Windows_NT'">.so</LibExtension>
+      <LibExtension Condition="$([MSBuild]::IsOSPlatform('osx'))">.dylib</LibExtension>
 
-		<TargetArchitecture Condition="'$(Platform)' == ''">x64</TargetArchitecture>
-		<NativeTargetArchitecture Condition="'$(NativeTargetArchitecture)' == ''">$(TargetArchitecture)</NativeTargetArchitecture>
-		<BinDir Condition="'$(BinDir)'==''">$([MSBuild]::NormalizeDirectory('$(RepoRoot)', 'artifacts', 'bin'))</BinDir>
-		<NativeOutputPath>$(BinDir)Native\$(NativeTargetArchitecture).$(Configuration)\</NativeOutputPath>
+      <BinDir Condition="'$(BinDir)'==''">$([MSBuild]::NormalizeDirectory('$(RepoRoot)', 'artifacts', 'bin'))</BinDir>
+      <NativeOutputPath>$(BinDir)Native\$(TargetArchitecture).$(Configuration)\</NativeOutputPath>
 
-		<Platform Condition="'$(Platform)'==''">AnyCPU</Platform>
-		<PlatformConfig>$(Platform).$(Configuration)</PlatformConfig>
-		<OutputPath Condition="'$(OutputPath)'==''">$(BinDir)$(MSBuildProjectName)\Debug</OutputPath>
-	</PropertyGroup>
+      <Platform Condition="'$(Platform)'==''">AnyCPU</Platform>
+      <PlatformConfig>$(Platform).$(Configuration)</PlatformConfig>
+      <OutputPath Condition="'$(OutputPath)'==''">$(BinDir)$(MSBuildProjectName)\Debug</OutputPath>
+	  </PropertyGroup>
 
 		<ItemGroup>
-		<NativeAssemblyReference>
-			<FullAssemblyPath>$(NativeOutputPath)$(LibPrefix)%(NativeAssemblyReference.Identity)$(LibExtension)</FullAssemblyPath>
-		</NativeAssemblyReference>
+      <NativeAssemblyReference>
+        <FullAssemblyPath>$(NativeOutputPath)$(LibPrefix)%(NativeAssemblyReference.Identity)$(LibExtension)</FullAssemblyPath>
+      </NativeAssemblyReference>
 		</ItemGroup>
 
+    <ItemGroup Condition="'$(TargetArchitecture)' == 'arm64' Or '$(TargetArchitecture)' == 'arm'">
+      <NativeAssemblyReference Remove="MklImports"/>
+      <NativeAssemblyReference Remove="CpuMathNative"/>
+      <NativeAssemblyReference Remove="FastTreeNative"/>
+      <NativeAssemblyReference Remove="SymSgdNative"/>
+      <NativeAssemblyReference Remove="MklProxyNative"/>
+    </ItemGroup>
+
 		<Copy SourceFiles = "@(NativeAssemblyReference->'%(FullAssemblyPath)')"
 			DestinationFolder="$(OutDir)"
 			OverwriteReadOnlyFiles="$(OverwriteReadOnlyFiles)"

diff --git a/docs/building/unix-instructions.md b/docs/building/unix-instructions.md
@@ -39,6 +39,22 @@ sudo apt-get install libssl1.0.0 libicu55
 sudo apt-get install libomp-dev
 ```
 
+#### Cross compiling for ARM
+
+Cross compilation is only supported on an Ubuntu host, 18.x and newer, and only .Net Core 3.1 or newer. You will need to install debootstrap and qemu-user-static to facilitate the process. Once they are installed you will need to build the cross compiling rootfs. We provide a script, `build-rootfs.sh`, to do this. You will also need to set the ROOTFS_DIR environment variable to the location of the rootfs you just created. The general process is as follows:
+
+```sh
+sudo apt-get update
+sudo apt-get install debootstrap qemu-user-static
+sudo ./eng/common/cross/build-rootfs.sh <target architecture> <ubuntu distro name> --rootfsdir <new rootfs location>
+export ROOTFS_DIR=<new rootfs location>
+
+# The cross compiling environment is now setup and you can proceed with a normal build
+./build.sh -c Release-netcoreapp3_1 /p:TargetArchitecture=<target architecture>
+```
+
+Note that the `<target architecture>` will usually be arm or arm64 and the `<ubuntu distro name>` is bionic for 18.04.
+
 ### macOS
 
 macOS 10.13 (High Sierra) or higher is needed to build dotnet/machinelearning. We are using a .NET Core 3.1 SDK to build, which supports 10.13 or higher.

diff --git a/docs/building/windows-instructions.md b/docs/building/windows-instructions.md
@@ -9,7 +9,7 @@ You can build ML.NET either via the command line or by using Visual Studio.
 2. **[CMake](https://cmake.org/)** must be installed from [the CMake download page](https://cmake.org/download/#latest) and added to your path.
 
 ### Visual Studio 2019 Installation
-We have successfully verified the below build instructions for Visual Studio version 16.4 and higher. 
+We have successfully verified the below build instructions for Visual Studio version 16.4 and higher.
 
 #### Visual Studio 2019 - 'Workloads' based install
 
@@ -37,6 +37,12 @@ The following are the minimum requirements:
   * .NET Framework 4.6 Targeting Pack
   * Windows Universal CRT SDK
 
+#### Visual Studio 2019 - Cross compilation for ARM
+
+If you want to cross compile for arm you will also need from the 'Individual components' section:
+  * MSVC v142 - VS 2019 C++ ARM build tools
+  * MSVC v142 - VS 2019 C++ ARM64 build tools
+
 ## Building Instructions
 
 In order to fetch dependencies which come through Git submodules the following command needs to be run before building: `git submodule update --init`.
@@ -51,7 +57,7 @@ After successfully running the command, the project can be built directly from t
 
 ### Building From the Command Line
 
-You can use the Developer Command Prompt, Powershell or work in any regular cmd. The Developer Command Prompt will have a name like "Developer Command Prompt for VS 2019" or similar in your start menu. 
+You can use the Developer Command Prompt, Powershell or work in any regular cmd. The Developer Command Prompt will have a name like "Developer Command Prompt for VS 2019" or similar in your start menu.
 
 From a (non-admin) Command Prompt window:
 
@@ -61,6 +67,20 @@ From a (non-admin) Command Prompt window:
 
 **Note**: Before working on individual projects or test projects you **must** run `build.cmd` from the root once before beginning that work. It is also a good idea to run `build.cmd` whenever you pull a large set of unknown changes into your branch.
 
+### Cross compiling for ARM
+
+You can use the Developer Command Prompt, Powershell or work in any regular cmd. The Developer Command Prompt will have a name like "Developer Command Prompt for VS 2019" or similar in your start menu.
+
+From a (non-admin) Command Prompt window based on what you want to target:
+
+- `build.cmd /p:TargetArchitecture=arm`
+- `build.cmd /p:TargetArchitecture=arm64`
+
+You can then pack them into nugets, pick the same target architecture you built with:
+
+- `build.cmd /p:TargetArchitecture=arm -pack`
+- `build.cmd /p:TargetArchitecture=arm64 -pack`
+
 ## Running Tests
 
 ### Running tests from Visual Studio

diff --git a/eng/common/cross/build-rootfs.sh b/eng/common/cross/build-rootfs.sh
@@ -57,6 +57,10 @@ __UbuntuPackages+=" libssl-dev"
 __UbuntuPackages+=" zlib1g-dev"
 __UbuntuPackages+=" libldap2-dev"
 
+# ML.NET dependencies
+__UbuntuPackages+=" libomp5"
+__UbuntuPackages+=" libomp-dev"
+
 __AlpinePackages+=" curl-dev"
 __AlpinePackages+=" krb5-dev"
 __AlpinePackages+=" openssl-dev"

diff --git a/src/Microsoft.ML.FastTree/Dataset/DenseIntArray.cs b/src/Microsoft.ML.FastTree/Dataset/DenseIntArray.cs
@@ -24,10 +24,11 @@ internal abstract class DenseIntArray : IntArray, IIntArrayForwardIndexer
     {
         public override IntArrayType Type { get { return IntArrayType.Dense; } }
 
-        protected DenseIntArray(int length)
+        protected DenseIntArray(int length, PerformSumup sumupHandler = null)
         {
             Contracts.Assert(length >= 0);
             Length = length;
+            SumupHandler = sumupHandler;
         }
 
         public override int Length { get; }
@@ -70,7 +71,6 @@ public override IntArray[] Split(int[][] assignment)
             return newArrays;
         }
 
-#if USE_FASTTREENATIVE
         internal const string NativePath = "FastTreeNative";
         [DllImport(NativePath), SuppressUnmanagedCodeSecurity]
         private static extern unsafe int C_Sumup_float(
@@ -111,8 +111,6 @@ protected static unsafe void SumupCPlusPlusDense(SumupInputData input, FeatureHi
             }
         }
 
-#endif
-
         public override IIntArrayForwardIndexer GetIndexer()
         {
             return this;
@@ -391,18 +389,21 @@ public Dense8BitIntArray(int len)
             : base(len)
         {
             _data = new byte[len];
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense8BitIntArray(byte[] buffer, ref int position)
             : base(buffer.ToInt(ref position))
         {
             _data = buffer.ToByteArray(ref position);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense8BitIntArray(int len, IEnumerable<int> values)
             : base(len)
         {
             _data = values.Select(i => (byte)i).ToArray(len);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         /// <summary>
@@ -445,8 +446,7 @@ public override unsafe int this[int index]
             }
         }
 
-#if USE_FASTTREENATIVE
-        public override void Sumup(SumupInputData input, FeatureHistogram histogram)
+        private void SumupNative(SumupInputData input, FeatureHistogram histogram)
         {
             unsafe
             {
@@ -456,7 +456,8 @@ public override void Sumup(SumupInputData input, FeatureHistogram histogram)
                 }
             }
         }
-#endif
+
+        public override void Sumup(SumupInputData input, FeatureHistogram histogram) => SumupHandler(input, histogram);
     }
 
     /// <summary>
@@ -475,12 +476,14 @@ public Dense4BitIntArray(int len)
             : base(len)
         {
             _data = new byte[(len + 1) / 2]; // Even length = half the bytes. Odd length = half the bytes+0.5.
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense4BitIntArray(int len, IEnumerable<int> values)
             : base(len)
         {
             _data = new byte[(len + 1) / 2];
+            SetupSumupHandler(SumupNative, base.Sumup);
 
             int currentIndex = 0;
             bool upper = true;
@@ -505,6 +508,7 @@ public Dense4BitIntArray(byte[] buffer, ref int position)
             : base(buffer.ToInt(ref position))
         {
             _data = buffer.ToByteArray(ref position);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         /// <summary>
@@ -565,8 +569,7 @@ public override unsafe int this[int index]
             }
         }
 
-#if USE_FASTTREENATIVE
-        public override void Sumup(SumupInputData input, FeatureHistogram histogram)
+        public void SumupNative(SumupInputData input, FeatureHistogram histogram)
         {
             unsafe
             {
@@ -576,7 +579,8 @@ public override void Sumup(SumupInputData input, FeatureHistogram histogram)
                 }
             }
         }
-#endif
+
+        public override void Sumup(SumupInputData input, FeatureHistogram histogram) => SumupHandler(input, histogram);
     }
 
     /// <summary>
@@ -592,18 +596,21 @@ public Dense16BitIntArray(int len)
             : base(len)
         {
             _data = new ushort[len];
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense16BitIntArray(int len, IEnumerable<int> values)
             : base(len)
         {
             _data = values.Select(i => (ushort)i).ToArray(len);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense16BitIntArray(byte[] buffer, ref int position)
             : base(buffer.ToInt(ref position))
         {
             _data = buffer.ToUShortArray(ref position);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public override unsafe void Callback(Action<IntPtr> callback)
@@ -648,8 +655,8 @@ public override unsafe int this[int index]
                 _data[index] = (ushort)value;
             }
         }
-#if USE_FASTTREENATIVE
-        public override void Sumup(SumupInputData input, FeatureHistogram histogram)
+
+        public void SumupNative(SumupInputData input, FeatureHistogram histogram)
         {
             unsafe
             {
@@ -660,7 +667,9 @@ public override void Sumup(SumupInputData input, FeatureHistogram histogram)
                 }
             }
         }
-#endif
+
+        public override void Sumup(SumupInputData input, FeatureHistogram histogram) => SumupHandler(input, histogram);
+
     }
 
     /// <summary>
@@ -676,18 +685,21 @@ public Dense32BitIntArray(int len)
             : base(len)
         {
             _data = new int[len];
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense32BitIntArray(int len, IEnumerable<int> values)
             : base(len)
         {
             _data = values.ToArray(len);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public Dense32BitIntArray(byte[] buffer, ref int position)
             : base(buffer.ToInt(ref position))
         {
             _data = buffer.ToIntArray(ref position);
+            SetupSumupHandler(SumupNative, base.Sumup);
         }
 
         public override unsafe void Callback(Action<IntPtr> callback)
@@ -733,8 +745,7 @@ public override int this[int index]
             }
         }
 
-#if USE_FASTTREENATIVE
-        public override void Sumup(SumupInputData input, FeatureHistogram histogram)
+        public void SumupNative(SumupInputData input, FeatureHistogram histogram)
         {
             unsafe
             {
@@ -745,6 +756,7 @@ public override void Sumup(SumupInputData input, FeatureHistogram histogram)
                 }
             }
         }
-#endif
+
+        public override void Sumup(SumupInputData input, FeatureHistogram histogram) => SumupHandler(input, histogram);
     }
 }