Enable building on arm64

This chnage allows source-build to be cloned and built on arm64
machines. It shouldn't affect cross compilation at all, however. I have
tested this on RHEL 8 aarch64.

This change includes backports of the following pull-requests which have
been merged into their respective master branches:

- dotnet/aspnetcore#14790
- dotnet/aspnetcore#15354
- dotnet/installer#4102
- dotnet/core-setup#8468
- dotnet/corefx#40453

To support using darc on arm64, this commit removes the customizations
of LD_LIBRARY_PATH and instead forces darc to run again a .NET Core 3.0
runtime. This in-turn makes darc pick up the right libgit2sharp
automatically for the right set of platforms and architectures.

There's a number of existing build configuration that are
conditionalized on arm64, such as setting up a root file system. Those
they are actually only meant to be invoked when cross-compiling for
arm64 (on x86_64). This commit modifies those conditions to not apply
when building on an arm64 machine.

Author: omajid

build-source-tarball.sh

@@ -12,6 +12,32 @@ if [ -z "${1:-}" ]; then
     exit 1
 fi
 
+# Use uname to determine what the CPU is.
+cpuname=$(uname -p)
+# Some Linux platforms report unknown for platform, but the arch for machine.
+if [[ "$cpuname" == "unknown" ]]; then
+  cpuname=$(uname -m)
+fi
+
+case $cpuname in
+  aarch64)
+    targetArchitecture=arm64
+    ;;
+  amd64|x86_64)
+    targetArchitecture=x64
+    ;;
+  armv7l)
+    targetArchitecture=arm
+    ;;
+  i686)
+    targetArchitecture=x86
+    ;;
+  *)
+    echo "Unknown CPU $cpuname detected, treating it as x64"
+    targetArchitecture=x64
+    ;;
+esac
+
 TARBALL_ROOT=$1
 shift
 
@@ -148,9 +174,6 @@ git submodule foreach --quiet --recursive '
 # Now re-uberclone into the tarball src directory.  Since we reuse the .gitdirs, this shouldn't hit the network at all.
 ignored_repos="https://dev.azure.com/dnceng/internal/_git/dotnet-optimization;https://dev.azure.com/devdiv/DevDiv/_git/DotNet-Trusted;https://devdiv.visualstudio.com/DevDiv/_git/DotNet-Trusted;https://[email protected]/dnceng/internal/_git/dotnet-optimization;https://dev.azure.com/dnceng/internal/_git/dotnet-core-setup;https://github.com/dotnet/source-build-reference-packages"
 
-#export the LC_LIB_PATH for libgit2 so file as fedora fails to find it in the repodir
-export LD_LIBRARY_PATH=$CLI_PATH/tools/.store/microsoft.dotnet.darc/$DarcVersion/microsoft.dotnet.darc/$DarcVersion/tools/netcoreapp2.1/any/runtimes/rhel-x64/native/
-
 "$CLI_PATH/dotnet" "$DARC_DLL" clone --repos-folder=$TARBALL_ROOT/src/ --git-dir-folder $SCRIPT_ROOT/.git/modules/src/ --include-toolset --ignore-repos "$ignored_repos" --azdev-pat bogus --github-pat bogus --depth 0 --debug
 
 # now we don't need .git/modules/src or Darc anymore
@@ -208,28 +231,28 @@ cp $SCRIPT_ROOT/support/tarball/build.sh $TARBALL_ROOT/build.sh
 mkdir -p $TARBALL_ROOT/packages/prebuilt
 mkdir -p $TARBALL_ROOT/packages/source-built
 find $SCRIPT_ROOT/packages/restored/ -name '*.nupkg' -exec cp {} $TARBALL_ROOT/packages/prebuilt/ \;
-find $SCRIPT_ROOT/bin/obj/x64/Release/nuget-packages -name '*.nupkg' -exec cp {} $TARBALL_ROOT/packages/prebuilt/ \;
+find $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/nuget-packages -name '*.nupkg' -exec cp {} $TARBALL_ROOT/packages/prebuilt/ \;
 
 # Copy reference-packages from bin dir to reference-packages directory.
 # See corresponding change in dir.props to change ReferencePackagesBasePath conditionally in offline build.
 mkdir -p $TARBALL_ROOT/packages/reference
-cp -r $SCRIPT_ROOT/bin/obj/x64/Release/reference-packages/source $TARBALL_ROOT/packages/reference/source
-cp -r $SCRIPT_ROOT/bin/obj/x64/Release/reference-packages/staging $TARBALL_ROOT/packages/reference/staging
+cp -r $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/reference-packages/source $TARBALL_ROOT/packages/reference/source
+cp -r $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/reference-packages/staging $TARBALL_ROOT/packages/reference/staging
 
 # Copy tarballs to ./packages/archive directory
 mkdir -p $TARBALL_ROOT/packages/archive
-cp -r $SCRIPT_ROOT/bin/obj/x64/Release/external-tarballs/*.tar.gz $TARBALL_ROOT/packages/archive/
+cp -r $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/external-tarballs/*.tar.gz $TARBALL_ROOT/packages/archive/
 
 # Copy generated source from bin to src/generatedSrc
-cp -r $SCRIPT_ROOT/bin/obj/x64/Release/generatedSrc $TARBALL_ROOT/src/generatedSrc
+cp -r $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/generatedSrc $TARBALL_ROOT/src/generatedSrc
 
 if [ -e $SCRIPT_ROOT/testing-smoke/smoke-test-packages ]; then
     cp -rf $SCRIPT_ROOT/testing-smoke/smoke-test-packages $TARBALL_ROOT/packages
 fi
 
 echo 'Removing source-built packages from tarball prebuilts...'
 
-for built_package in $(find $SCRIPT_ROOT/bin/obj/x64/Release/blob-feed/packages/ -name '*.nupkg' | tr '[:upper:]' '[:lower:]')
+for built_package in $(find $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/blob-feed/packages/ -name '*.nupkg' | tr '[:upper:]' '[:lower:]')
 do
     if [ -e $TARBALL_ROOT/packages/prebuilt/$(basename $built_package) ]; then
         rm $TARBALL_ROOT/packages/prebuilt/$(basename $built_package)
@@ -250,8 +273,8 @@ cp $SCRIPT_ROOT/bin/obj/x64/Release/blob-feed/packages/*DotNetHost*.nupkg $TARBA
 cp $SCRIPT_ROOT/bin/obj/x64/Release/blob-feed/packages/*DotNetAppHost*.nupkg $TARBALL_ROOT/packages/source-built/
 
 # Setup package version props to include both source-built and running PackageVersions.props
-mkdir --parents $TARBALL_ROOT/bin/obj/x64/Release/
-cp $SCRIPT_ROOT/support/tarball/PackageVersions.props $TARBALL_ROOT/bin/obj/x64/Release/
+mkdir --parents $TARBALL_ROOT/bin/obj/$targetArchitecture/Release/
+cp $SCRIPT_ROOT/support/tarball/PackageVersions.props $TARBALL_ROOT/bin/obj/$targetArchitecture/Release/
 
 if [ $INCLUDE_LEAK_DETECTION -eq 1 ]; then
   echo 'Building leak detection MSBuild tasks...'
@@ -261,7 +284,7 @@ fi
 
 echo 'Removing reference-only packages from tarball prebuilts...'
 
-for ref_package in $(find $SCRIPT_ROOT/bin/obj/x64/Release/reference-packages/packages-to-delete/ -name '*.nupkg' | tr '[:upper:]' '[:lower:]')
+for ref_package in $(find $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/reference-packages/packages-to-delete/ -name '*.nupkg' | tr '[:upper:]' '[:lower:]')
 do
     if [ -e $TARBALL_ROOT/packages/prebuilt/$(basename $ref_package) ]; then
         rm $TARBALL_ROOT/packages/prebuilt/$(basename $ref_package)
@@ -292,7 +315,7 @@ done
 echo 'Removing source-built, previously source-built packages and reference packages from il pkg src...'
 OLDIFS=$IFS
 
-allBuiltPkgs=(`ls $SCRIPT_ROOT/bin/obj/x64/Release/blob-feed/packages/*.nupkg | xargs -n1 basename | tr '[:upper:]' '[:lower:]'`)
+allBuiltPkgs=(`ls $SCRIPT_ROOT/bin/obj/$targetArchitecture/Release/blob-feed/packages/*.nupkg | xargs -n1 basename | tr '[:upper:]' '[:lower:]'`)
 pushd $TARBALL_ROOT/packages/reference/staging/
 ilSrcPaths=(`find . -maxdepth 2 -mindepth 2`)
 popd

build.sh

@@ -69,8 +69,11 @@ export NUGET_PACKAGES="$scriptroot/packages/restored/"
 set -x
 scriptroot="$( cd -P "$( dirname "$source" )" && pwd )"
 
-# runtime 2.1.0 required for darc
-"$scriptroot/eng/common/dotnet-install.sh"  -runtime dotnet -version 2.1.0
+# HACK ALERT. runtime 2.1.0 required for darc. But that doesn't work too well on arm64. Instead, pretend 3.0.0 is 2.1.0.
+"$scriptroot/eng/common/dotnet-install.sh"  -runtime dotnet -version 3.0.0
+if [ ! -e $scriptroot/.dotnet/shared/Microsoft.NETCore.App/2.1.0 ]; then
+  ln -s 3.0.0 $scriptroot/.dotnet/shared/Microsoft.NETCore.App/2.1.0
+fi
 
 if [ "$alternateTarget" == "true" ]; then
   CLIPATH="$scriptroot/.dotnet"

dir.props

@@ -2,6 +2,9 @@
 <Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition="$(Configuration) == ''">Release</Configuration>
+
+    <BuildArchitecture>$([System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture.ToString().ToLowerInvariant())</BuildArchitecture>
+    <Platform Condition="'$(Platform)' == '' AND '$(BuildArchitecture)' == 'arm64'">$(BuildArchitecture)</Platform>
     <Platform Condition="'$(Platform)' == ''">x64</Platform>
 
     <!-- true if we have bootstrapped buildtools (usually on an unsupported platform -->
@@ -198,7 +201,7 @@
     <ExtraPackageVersionPropsPackageInfo Include="MicrosoftNETCoreAppRuntimePackageVersion" Version="%24(MicrosoftNETCoreDotNetAppHostPackageVersion)" />
     <ExtraPackageVersionPropsPackageInfo Include="MicrosoftNETCoreAppRuntimeVersion" Version="%24(MicrosoftNETCoreDotNetAppHostPackageVersion)" />
     <ExtraPackageVersionPropsPackageInfo Include="MicrosoftNETCoreAppHostPackageVersion" Version="%24(MicrosoftNETCoreDotNetAppHostPackageVersion)" />
-    <ExtraPackageVersionPropsPackageInfo Include="MicrosoftAspNetCoreAppRuntimePackageVersion" Version="%24(MicrosoftAspNetCoreAppRuntimeLinuxX64PackageVersion)" />
+    <ExtraPackageVersionPropsPackageInfo Include="MicrosoftAspNetCoreAppRuntimePackageVersion" Version="%24(MicrosoftAspNetCoreAppRuntimeLinux$(Platform)PackageVersion)" />
     <!-- core-sdk uses this property for ASP.NET blob directory -->
     <ExtraPackageVersionPropsPackageInfo Include="VSRedistCommonAspNetCoreTargetingPackx6430PackageVersion" Version="$(aspnetcoreOutputPackageVersion)" />
     <!-- OSX needs the OSX version instead of Linux.  We don't have a lot of flexibility in how we output these properties so we're relying on the previous one being blank if the Linux version of the package is missing.  -->

patches/aspnetcore/0011-Support-global.json-on-arm64-as-well.patch

@@ -0,0 +1,33 @@
+From 84d274a8f3d416b0a5bd999e3d1c43ae1535e38f Mon Sep 17 00:00:00 2001
+From: Omair Majid <[email protected]>
+Date: Wed, 23 Oct 2019 15:43:57 -0400
+Subject: [PATCH] Support global.json on arm64 as well
+
+arcade uses the runtime section of global.json to decide which
+architecture + runtime combination needs to be installed.
+
+With https://github.com/dotnet/arcade/pull/4132 arcade can install
+foreign SDKs in separate locations correctly.
+
+This change, suggested by @dougbu, makes arcade always install the
+runtime for the local architecture (which means it should work on arm64
+and x64) as well as the x86 architecture (skipped on Linux).
+
+This gets us a working SDK/Runtime combo on arm64.
+---
+ global.json | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/global.json b/global.json
+index 602f4f44e17..40dec559cc9 100644
+--- a/global.json
++++ b/global.json
+@@ -5,7 +5,7 @@
+   "tools": {
+     "dotnet": "3.0.100",
+     "runtimes": {
+-      "dotnet/x64": [
++      "dotnet": [
+         "$(MicrosoftNETCoreAppRuntimeVersion)"
+       ],
+       "dotnet/x86": [

patches/aspnetcore/0012-Support-building-for-arm64-on-arm64-nix.patch

@@ -0,0 +1,85 @@
+From e2946a26c11be7f7f0c223721a5b14f58f2ea240 Mon Sep 17 00:00:00 2001
+From: Omair Majid <[email protected]>
+Date: Mon, 11 Nov 2019 13:37:40 -0500
+Subject: [PATCH] Support building for arm64 on arm64 (*nix)
+
+This commit allows ASP.NET Core to be built on arm64 machines directly,
+without relying on cross-compilation.
+
+There's a few changes in here:
+
+1. Ask msbuild to look into the BuildArchitecture
+
+   By default, our build systems assums the machine is x64. This
+   modifies the build configuration to check the architecture of the
+   currently running build machine, and set BuildArchitecture to that.
+
+2. Fix crossgen in Microsoft.AspNetCore.App.Runtime
+
+   We run crossgen for supported architectures (including x64 and
+   arm64). For that, we need a jit that we can point crossgen to.
+   Generally, we can rely on the build scripts to find the right
+   `libclrjit.so`. However, arm64 has multiple `libclirjit.so`, for
+   different use-cases. There's one for arm64 (for running on arm64) and
+   there's another one for cross-compiling for arm64 on x64. We need to
+   figure out and use the right one explicitly rather than assuming the
+   right one gets picked up.
+
+   See https://github.com/dotnet/core-setup/pull/8468 for similar
+   changes made in core-setup.
+
+This also needs https://github.com/aspnet/AspNetCore/pull/14790 to fully
+work on arm64.
+---
+ Directory.Build.props                                |  1 +
+ .../src/Microsoft.AspNetCore.App.Runtime.csproj      | 12 ++++++++----
+ 2 files changed, 9 insertions(+), 4 deletions(-)
+
+diff --git a/Directory.Build.props b/Directory.Build.props
+index b3dc903387f..1bd59d73121 100644
+--- a/Directory.Build.props
++++ b/Directory.Build.props
+@@ -108,6 +108,7 @@
+     <TargetOsName Condition=" '$(TargetOsName)' == '' AND $([MSBuild]::IsOSPlatform('Windows'))">win</TargetOsName>
+     <TargetOsName Condition=" '$(TargetOsName)' == '' AND $([MSBuild]::IsOSPlatform('OSX'))">osx</TargetOsName>
+     <TargetOsName Condition=" '$(TargetOsName)' == '' AND $([MSBuild]::IsOSPlatform('Linux'))">linux</TargetOsName>
++    <BuildArchitecture>$([System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture.ToString().ToLowerInvariant())</BuildArchitecture>
+     <TargetArchitecture Condition="'$(TargetArchitecture)' == ''">x64</TargetArchitecture>
+     <TargetRuntimeIdentifier>$(TargetOsName)-$(TargetArchitecture)</TargetRuntimeIdentifier>
+ 
+diff --git a/src/Framework/src/Microsoft.AspNetCore.App.Runtime.csproj b/src/Framework/src/Microsoft.AspNetCore.App.Runtime.csproj
+index 4c4298a92da..f843ded1241 100644
+--- a/src/Framework/src/Microsoft.AspNetCore.App.Runtime.csproj
++++ b/src/Framework/src/Microsoft.AspNetCore.App.Runtime.csproj
+@@ -90,15 +90,17 @@ This package is an internal implementation of the .NET Core SDK and is not meant
+     <PathSeparator Condition="'$(PathSeparator)' == ''">:</PathSeparator>
+     <PathSeparator Condition=" '$(TargetOsName)' == 'win' ">%3B</PathSeparator>
+ 
++    <CrossCompileDirectory Condition=" '$(TargetRuntimeIdentifier)' == 'linux-arm' ">x64_arm</CrossCompileDirectory>
++    <CrossCompileDirectory Condition=" '$(TargetArchitecture)' == 'arm64' AND '$(BuildArchitecture)' != 'arm64' ">x64_arm64</CrossCompileDirectory>
++    <CrossCompileDirectory Condition=" '$(TargetRuntimeIdentifier)' == 'win-arm' ">x86_arm</CrossCompileDirectory>
++
+     <!-- Crossgen executable name -->
+     <CrossgenToolFileName>crossgen</CrossgenToolFileName>
+     <CrossgenToolFileName Condition=" '$(TargetOsName)' == 'win' ">$(CrossgenToolFileName).exe</CrossgenToolFileName>
+     <!-- Default crossgen executable relative path -->
+     <CrossgenToolPackagePath>$(CrossgenToolFileName)</CrossgenToolPackagePath>
+     <!-- Disambiguated RID-specific crossgen executable relative path -->
+-    <CrossgenToolPackagePath Condition=" '$(TargetRuntimeIdentifier)' == 'linux-arm' ">x64_arm\$(CrossgenToolPackagePath)</CrossgenToolPackagePath>
+-    <CrossgenToolPackagePath Condition=" '$(TargetRuntimeIdentifier)' == 'linux-arm64' OR '$(TargetRuntimeIdentifier)' == 'linux-musl-arm64' ">x64_arm64\$(CrossgenToolPackagePath)</CrossgenToolPackagePath>
+-    <CrossgenToolPackagePath Condition=" '$(TargetRuntimeIdentifier)' == 'win-arm' ">x86_arm\$(CrossgenToolPackagePath)</CrossgenToolPackagePath>
++    <CrossgenToolPackagePath Condition=" '$(CrossCompileDirectory)' != '' ">$(CrossCompileDirectory)\$(CrossgenToolPackagePath)</CrossgenToolPackagePath>
+ 
+     <MicrosoftNETCoreAppRuntimeIdentifier>$(RuntimeIdentifier)</MicrosoftNETCoreAppRuntimeIdentifier>
+     <MicrosoftNETCoreAppRuntimeIdentifier Condition="'$(TargetOsName)' != 'osx'">$(SourceBuildRuntimeIdentifier)</MicrosoftNETCoreAppRuntimeIdentifier>
+@@ -293,7 +295,9 @@ This package is an internal implementation of the .NET Core SDK and is not meant
+   <PropertyGroup>
+     <CrossgenToolDir>$(IntermediateOutputPath)crossgen\</CrossgenToolDir>
+     <CrossgenPlatformAssembliesDir>$(IntermediateOutputPath)platformAssemblies\</CrossgenPlatformAssembliesDir>
+-    <CoreCLRJitPath>$(CrossgenToolDir)$(LibPrefix)clrjit$(LibExtension)</CoreCLRJitPath>
++    <!-- Pick the right coreclr jit based on whether we are cross-compiling or not -->
++    <CoreCLRJitPath Condition="'$(CrossCompileDirectory)' == ''">$(RuntimePackageRoot)runtimes\$(RuntimeIdentifier)\native\$(LibPrefix)clrjit$(LibExtension)</CoreCLRJitPath>
++    <CoreCLRJitPath Condition="'$(CrossCompileDirectory)' != ''">$(RuntimepackageRoot)runtimes\$(CrossCompileDirectory)\native\$(LibPrefix)clrjit$(LibExtension)</CoreCLRJitPath>
+   </PropertyGroup>
+ 
+   <ItemGroup>