[monodroid] Build the Xamarin.Android runtime for net6

This commit makes changes to build the native Xamarin.Android runtime
against Mono VM shipped from the `dotnet/runtime` repository in nuget
packages which also contain header files necessary to embed Mono in
Xamarin.Android.

Xamarin.Android runtime is now built separately for the "legacy" target,
using Mono from the SDK archives, and for net6.  This change required
introduction of new target directories in `$XA_INSTALL_ROOT/lib`:

  * arm64-v8a-net6
  * armeabi-v7a-net6
  * x86_64-net6
  * x86-net6

These directories now contain only the shared libraries together
comprising the Xamarin.Android runtime:

  * libmono-android.*.so
  * libxamarin-debug-app-helper*.so
  * libxamarin-app.so

Mono runtime libraries are not copied from their respective nuget
packages.  Compared to the "legacy" builds, we are missing the
`libMonoPosixHelper.so` library.  The helper DSO will be eventually
placed in a `Mono.Posix` nuget, once we are able to separate
`Mono.Posix` files from the Mono sources and place them in a separate
repository.

`xaprepare` is modified to generate MSBuild and cmake fragments
responsible for building net6 runtime binaries.

Native runtime now doesn't export any p/invoke entry points, instead it
uses the new `PINVOKE_OVERRIDE` mechanism to handle the p/invoke
dispatch internally.  This allows us to not only hide the public
symbols, but also remove the `libxa-internal-api.so` library completely.

.external

@@ -1,2 +1,2 @@
-xamarin/monodroid:main@2e93b630e47701dae56f426fe5934846d571832b
+xamarin/monodroid:main@dade1f497271f3ae5ceb1fe8c6c672b399a369ec
 mono/mono:2020-02@c66141a8c7ba2566c578c2dd012b2b723e006213

.gitmodules

@@ -43,3 +43,7 @@
     path = external/xamarin-android-tools
     url = https://github.com/xamarin/xamarin-android-tools
     branch = main
+[submodule "external/robin-map"]
+	path = external/robin-map
+	url = https://github.com/Tessil/robin-map.git
+	branch = master

Configuration.props

@@ -75,8 +75,11 @@
     <DotNetPreviewPath Condition=" '$(DotNetPreviewPath)' == '' ">$(AndroidToolchainDirectory)\dotnet\</DotNetPreviewPath>
     <DotNetPreviewTool Condition=" '$(DotNetPreviewTool)' == '' ">$(DotNetPreviewPath)dotnet</DotNetPreviewTool>
     <!-- Version number from: https://github.com/dotnet/installer#installers-and-binaries -->
+    <!-- Please update DotNetRuntimePacksVersion below accordingly -->
     <DotNetPreviewVersionBand Condition=" '$(DotNetPreviewVersionBand)' == '' ">6.0.100</DotNetPreviewVersionBand>
     <DotNetPreviewVersionFull Condition=" '$(DotNetPreviewVersionFull)' == '' ">$(DotNetPreviewVersionBand)-preview.1.21109.8</DotNetPreviewVersionFull>
+    <!-- This version comes from the a file in the dotnet distribution: sdk/$(DotNetPreviewVersionFull)/dotnet.runtimeconfig.json (the `runtimeOptions/framework/version key`) -->
+    <DotNetRuntimePacksVersion Condition=" '$(DotNetRuntimePacksVersion)' == '' ">6.0.0-preview.2.21108.2</DotNetRuntimePacksVersion>
     <ILLinkVersionBand Condition=" '$(ILLinkVersionBand)' == '' ">6.0.0</ILLinkVersionBand>
     <ILLinkVersionFull Condition=" '$(ILLinkVersionFull)' == '' ">$(ILLinkVersionBand)-alpha.1.21109.1</ILLinkVersionFull>
     <WixToolPath Condition=" '$(WixToolPath)' == '' ">$(AndroidToolchainDirectory)\wix\</WixToolPath>

ThirdPartyNotices.txt

@@ -15,6 +15,7 @@ The attached notices are provided for information only.
 2. bazelbuild/bazel (https://github.com/bazelbuild/bazel/)
 3. force-net/crc32.net (https://github.com/force-net/Crc32.NET)
 4. nunit/nunitlite (https://github.com/nunit/nunitlite/)
+5. tessil/robin-map (https://github.com/Tessil/robin-map)
 
 %% android/platform/tools/base NOTICES AND INFORMATION BEGIN HERE
 =================================================================
@@ -487,3 +488,31 @@ THE SOFTWARE.
 =====================================================
 END OF nunit/nunitlite NOTICES AND INFORMATION
 
+%% tessil/robin-map NOTICES AND INFORMATION BEGIN HERE
+======================================================
+MIT License
+
+Copyright (c) 2017 Thibaut Goetghebuer-Planchon <[email protected]>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+
+======================================================
+END OF tessil/robin-map NOTICES AND INFORMATION
+

build-tools/create-packs/Directory.Build.targets

@@ -77,10 +77,10 @@
   <Target Name="CreateAllPacks"
       DependsOnTargets="BuildILLinkCustomStep;DeleteExtractedWorkloadPacks;_SetGlobalProperties">
     <RemoveDir Directories="$(XamarinAndroidSourcePath)bin\Build$(Configuration)\nupkgs" />
-    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-arm -p:AndroidABI=armeabi-v7a &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
-    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-arm64 -p:AndroidABI=arm64-v8a &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
-    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-x86 -p:AndroidABI=x86 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
-    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-x64 -p:AndroidABI=x86_64 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
+    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-arm -p:AndroidABI=armeabi-v7a-net6 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
+    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-arm64 -p:AndroidABI=arm64-v8a-net6 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
+    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-x86 -p:AndroidABI=x86-net6 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
+    <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidRID=android-x64 -p:AndroidABI=x86_64-net6 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Runtime.proj&quot;" />
     <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Ref.proj&quot;" />
     <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidHostRID=linux-x64 &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Sdk.proj&quot;"     Condition=" '$(HostOS)' == 'Linux' " />
     <Exec Command="$(DotNetPreviewTool) pack @(_GlobalProperties, ' ') -p:AndroidHostRID=osx-x64   &quot;$(MSBuildThisFileDirectory)Microsoft.Android.Sdk.proj&quot;"     Condition=" '$(HostOS)' == 'Darwin' " />

build-tools/create-packs/Microsoft.Android.Runtime.proj

@@ -11,7 +11,7 @@ projects that use the Microsoft.Android framework in .NET 5.
 
   <PropertyGroup>
     <AndroidRID Condition=" '$(AndroidRID)' == '' ">android-arm64</AndroidRID>
-    <AndroidABI Condition=" '$(AndroidABI)' == '' ">arm64-v8a</AndroidABI>
+    <AndroidABI Condition=" '$(AndroidABI)' == '' ">arm64-v8a-net6</AndroidABI>
     <PackageId>Microsoft.Android.Runtime.$(AndroidRID)</PackageId>
     <Description>Microsoft.Android runtime components. Please do not reference directly.</Description>
     <_AndroidRuntimePackAssemblyPath>runtimes\$(AndroidRID)\lib\net6.0</_AndroidRuntimePackAssemblyPath>
@@ -39,7 +39,6 @@ projects that use the Microsoft.Android framework in .NET 5.
       <_AndroidRuntimePackAssemblies Include="$(_MonoAndroidNETOutputDir)Mono.Android.Export.dll" />
       <_AndroidRuntimePackAssets Include="$(XAInstallPrefix)xbuild\Xamarin\Android\lib\$(AndroidABI)\libmono-android.debug.so" />
       <_AndroidRuntimePackAssets Include="$(XAInstallPrefix)xbuild\Xamarin\Android\lib\$(AndroidABI)\libmono-android.release.so" />
-      <_AndroidRuntimePackAssets Include="$(XAInstallPrefix)xbuild\Xamarin\Android\lib\$(AndroidABI)\libxa-internal-api.so" />
       <_AndroidRuntimePackAssets Include="$(XAInstallPrefix)xbuild\Xamarin\Android\lib\$(AndroidABI)\libxamarin-debug-app-helper.so" />
       <FrameworkListFileClass Include="@(_AndroidRuntimePackAssemblies->'%(Filename)%(Extension)')" Profile="Android" />
       <FrameworkListFileClass Include="@(_AndroidRuntimePackAssets->'%(Filename)%(Extension)')" Profile="Android" />

build-tools/create-pkg/create-pkg.targets

@@ -27,6 +27,10 @@
       <MSBuildFrameworksDir>$(XAFrameworkDir)\lib\xamarin.android\xbuild-frameworks\MonoAndroid</MSBuildFrameworksDir>
     </PropertyGroup>
     <RemoveDir Directories="$(PayloadDir)" />
+    <ItemGroup>
+      <!-- Remove items with '%(ExcludeFromLegacy)' == 'true' metadata -->
+      <MSBuildItemsUnix Remove="@(MSBuildItemsUnix)" Condition=" '%(MSBuildItemsUnix.ExcludeFromLegacy)' == 'true' " />
+    </ItemGroup>
     <Copy
         SourceFiles="@(FrameworkItemsUnix)"
         DestinationFiles="@(FrameworkItemsUnix->'$(MSBuildFrameworksDir)\%(RelativePath)')"

build-tools/create-vsix/create-vsix.targets

@@ -32,6 +32,8 @@
       <ReferenceAssemblies Include="@(FrameworkItemsWin)" >
         <VSIXSubPath>Microsoft/Framework/MonoAndroid/$([System.IO.Path]::GetDirectoryName(%(RelativePath)))</VSIXSubPath>
       </ReferenceAssemblies>
+      <!-- Remove items with '%(ExcludeFromLegacy)' == 'true' metadata -->
+      <MSBuildItemsWin Remove="@(MSBuildItemsWin)" Condition=" '%(MSBuildItemsWin.ExcludeFromLegacy)' == 'true' " />
       <MSBuild Include="@(MSBuildItemsWin)" >
         <VSIXSubPath>Xamarin/Android/$([System.IO.Path]::GetDirectoryName(%(RelativePath)))</VSIXSubPath>
       </MSBuild>

build-tools/installers/create-installers.targets

@@ -227,10 +227,14 @@
     <_MSBuildFiles Include="$(MSBuildSrcDir)\startup-xf.aotprofile" />
     <_MSBuildFiles Include="$(MSBuildSrcDir)\r8.jar" />
     <_MSBuildFiles Include="$(MSBuildSrcDir)\bundletool.jar" ExcludeFromAndroidNETSdk="true" />
-    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime.jar" />
-    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev.jar" />
-    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime.dex" />
-    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev.dex" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime.jar" ExcludeFromAndroidNETSdk="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev.jar" ExcludeFromAndroidNETSdk="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime.dex" ExcludeFromAndroidNETSdk="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev.dex" ExcludeFromAndroidNETSdk="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_net6.jar" ExcludeFromLegacy="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev_net6.jar" ExcludeFromLegacy="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_net6.dex" ExcludeFromLegacy="true" />
+    <_MSBuildFiles Include="$(MSBuildSrcDir)\java_runtime_fastdev_net6.dex" ExcludeFromLegacy="true" />
     <_MSBuildFiles Include="$(MSBuildSrcDir)\manifestmerger.jar" />
     <_MSBuildFiles Include="$(MSBuildSrcDir)\protobuf-net.dll" />
     <_MSBuildFiles Include="$(MSBuildSrcDir)\SgmlReaderDll.dll" />

build-tools/scripts/Ndk.projitems.in

@@ -3,34 +3,42 @@
   <PropertyGroup>
     <AndroidNdkVersion Condition=" '$(AndroidNdkVersion)' == '' ">@NDK_RELEASE@</AndroidNdkVersion>
     <AndroidNdkApiLevel_ArmV7a Condition=" '$(AndroidNdkApiLevel_ArmV7a)' == '' ">@NDK_ARMEABI_V7_API@</AndroidNdkApiLevel_ArmV7a>
+    <AndroidNdkApiLevel_ArmV7a_NET6 Condition=" '$(AndroidNdkApiLevel_ArmV7a_NET6)' == '' ">@NDK_ARMEABI_V7_API_NET6@</AndroidNdkApiLevel_ArmV7a_NET6>
     <AndroidNdkApiLevel_ArmV8a Condition=" '$(AndroidNdkApiLevel_ArmV8a)' == '' ">@NDK_ARM64_V8A_API@</AndroidNdkApiLevel_ArmV8a>
+    <AndroidNdkApiLevel_ArmV8a_NET6 Condition=" '$(AndroidNdkApiLevel_ArmV8a_NET6)' == '' ">@NDK_ARM64_V8A_API_NET6@</AndroidNdkApiLevel_ArmV8a_NET6>
     <AndroidNdkApiLevel_X86 Condition=" '$(AndroidNdkApiLevel_X86)' == '' ">@NDK_X86_API@</AndroidNdkApiLevel_X86>
+    <AndroidNdkApiLevel_X86_NET6 Condition=" '$(AndroidNdkApiLevel_X86_NET6)' == '' ">@NDK_X86_API_NET6@</AndroidNdkApiLevel_X86_NET6>
     <AndroidNdkApiLevel_X86_64 Condition=" '$(AndroidNdkApiLevel_X86_64)' == '' ">@NDK_X86_64_API@</AndroidNdkApiLevel_X86_64>
+    <AndroidNdkApiLevel_X86_64_NET6 Condition=" '$(AndroidNdkApiLevel_X86_64_NET6)' == '' ">@NDK_X86_64_API_NET6@</AndroidNdkApiLevel_X86_64_NET6>
   </PropertyGroup>
 
   <ItemGroup>
     <AndroidSupportedTargetJitAbi
         Include="armeabi-v7a"
         Condition=" $(AndroidSupportedTargetJitAbisForConditionalChecks.Contains (':armeabi-v7a:')) ">
       <ApiLevel>$(AndroidNdkApiLevel_ArmV7a)</ApiLevel>
+      <ApiLevelNET6>$(AndroidNdkApiLevel_ArmV7a_NET6)</ApiLevelNET6>
     </AndroidSupportedTargetJitAbi>
 
     <AndroidSupportedTargetJitAbi
         Include="arm64-v8a"
         Condition=" $(AndroidSupportedTargetJitAbisForConditionalChecks.Contains (':arm64-v8a:')) ">
       <ApiLevel>$(AndroidNdkApiLevel_ArmV8a)</ApiLevel>
+      <ApiLevelNET6>$(AndroidNdkApiLevel_ArmV8a_NET6)</ApiLevelNET6>
     </AndroidSupportedTargetJitAbi>
 
     <AndroidSupportedTargetJitAbi
         Include="x86"
         Condition=" $(AndroidSupportedTargetJitAbisForConditionalChecks.Contains (':x86:')) ">
       <ApiLevel>$(AndroidNdkApiLevel_X86)</ApiLevel>
+      <ApiLevelNET6>$(AndroidNdkApiLevel_X86_NET6)</ApiLevelNET6>
     </AndroidSupportedTargetJitAbi>
 
     <AndroidSupportedTargetJitAbi
         Include="x86_64"
         Condition=" $(AndroidSupportedTargetJitAbisForConditionalChecks.Contains (':x86_64:')) ">
       <ApiLevel>$(AndroidNdkApiLevel_X86_64)</ApiLevel>
+      <ApiLevelNET6>$(AndroidNdkApiLevel_X86_64_NET6)</ApiLevelNET6>
     </AndroidSupportedTargetJitAbi>
   </ItemGroup>
 </Project>

build-tools/scripts/xa_build_configuration.cmake.in

@@ -0,0 +1,4 @@
+set(NETCORE_APP_RUNTIME_DIR_ARM "@NETCORE_APP_RUNTIME_ANDROID_ARM@")
+set(NETCORE_APP_RUNTIME_DIR_ARM64 "@NETCORE_APP_RUNTIME_ANDROID_ARM64@")
+set(NETCORE_APP_RUNTIME_DIR_X86 "@NETCORE_APP_RUNTIME_ANDROID_X86@")
+set(NETCORE_APP_RUNTIME_DIR_X86_64 "@NETCORE_APP_RUNTIME_ANDROID_X86_64@")

build-tools/xaprepare/xaprepare/Application/GeneratedMonodroidCmakeFiles.cs

@@ -40,16 +40,20 @@ public override void Generate (Context context)
 
 		static readonly Dictionary<string, string> ApiLevelVariableNames = new Dictionary<string, string> (StringComparer.Ordinal) {
 			{ AbiNames.TargetJit.AndroidArmV7a, "NDK_LEGACY_API_ARMV7A" },
+			{ BuildAndroidPlatforms.AndroidArmV7a_NET6, "NDK_NET6_API_ARMV7A" },
 			{ AbiNames.TargetJit.AndroidArmV8a, "NDK_LEGACY_API_ARMV8A" },
+			{ BuildAndroidPlatforms.AndroidArmV8a_NET6, "NDK_NET6_API_ARMV8A" },
 			{ AbiNames.TargetJit.AndroidX86, "NDK_LEGACY_API_X86" },
+			{ BuildAndroidPlatforms.AndroidX86_NET6, "NDK_NET6_API_X86" },
 			{ AbiNames.TargetJit.AndroidX86_64, "NDK_LEGACY_API_X86_64" },
+			{ BuildAndroidPlatforms.AndroidX86_64_NET6, "NDK_NET6_API_X86_64" },
 		};
 
 		static readonly Dictionary<string, string> JitAbis = new Dictionary<string, string> (StringComparer.Ordinal) {
-			{ AbiNames.TargetJit.AndroidArmV7a, String.Empty },
-			{ AbiNames.TargetJit.AndroidArmV8a, String.Empty },
-			{ AbiNames.TargetJit.AndroidX86, String.Empty },
-			{ AbiNames.TargetJit.AndroidX86_64, String.Empty },
+			{ AbiNames.TargetJit.AndroidArmV7a, BuildAndroidPlatforms.AndroidArmV7a_NET6 },
+			{ AbiNames.TargetJit.AndroidArmV8a, BuildAndroidPlatforms.AndroidArmV8a_NET6 },
+			{ AbiNames.TargetJit.AndroidX86, BuildAndroidPlatforms.AndroidX86_NET6 },
+			{ AbiNames.TargetJit.AndroidX86_64, BuildAndroidPlatforms.AndroidX86_64_NET6 },
 		};
 
 		static readonly Dictionary<string, string> HostAbis = new Dictionary<string, string> (StringComparer.Ordinal) {
@@ -107,9 +111,13 @@ void GenerateShellConfig (Context context, StreamWriter sw)
 			sw.WriteLine ();
 
 			WriteApiLevelVariable (AbiNames.TargetJit.AndroidArmV7a);
+			WriteApiLevelVariable (BuildAndroidPlatforms.AndroidArmV7a_NET6);
 			WriteApiLevelVariable (AbiNames.TargetJit.AndroidArmV8a);
+			WriteApiLevelVariable (BuildAndroidPlatforms.AndroidArmV8a_NET6);
 			WriteApiLevelVariable (AbiNames.TargetJit.AndroidX86);
+			WriteApiLevelVariable (BuildAndroidPlatforms.AndroidX86_NET6);
 			WriteApiLevelVariable (AbiNames.TargetJit.AndroidX86_64);
+			WriteApiLevelVariable (BuildAndroidPlatforms.AndroidX86_64_NET6);
 			sw.WriteLine ();
 
 			string indent = "\t";
@@ -240,8 +248,8 @@ void WriteShellRuntimeCommand (StreamWriter sw, Dictionary<string, string> abis,
 
 			foreach (var kvp in abis) {
 				string abi = kvp.Key;
-				string apiLevelVarName = kvp.Key;
-				string outputDirName = abi;
+				string apiLevelVarName = command.IsNet6 ? kvp.Value : kvp.Key;
+				string outputDirName = command.IsNet6 ? $"{abi}-net6" : abi;
 				string isMxe = "no";
 				string mxeBitness = String.Empty;
 				bool forMxe = false;
@@ -353,7 +361,6 @@ void GenerateMonodroidTargets (Context context, StreamWriter sw)
 				{ "@NATIVE_API_LEVEL@", "" },
 				{ "@ABI@", "%(AndroidSupportedTargetJitAbi.Identity)" },
 				{ "@OUTPUT_DIRECTORY@", "" },
-
 			};
 
 			var hostRuntimeReplacements = new Dictionary<string, string> (StringComparer.Ordinal) {
@@ -419,12 +426,13 @@ string EnsureRequired (string name, string v)
 		void WriteMSBuildConfigureAndroidRuntimeCommands (StreamWriter sw, string indent, CmakeBuilds.RuntimeCommand command, Dictionary<string, string> replacements)
 		{
 			const string LegacyOutputDirectory = "$(OutputPath)%(AndroidSupportedTargetJitAbi.Identity)";
+			const string Net6OutputDirectory = LegacyOutputDirectory + "-net6";
 
 			WriteMSBuildConfigureRuntimeCommands (
 				sw,
 				indent,
 				$"$(IntermediateOutputPath)%(AndroidSupportedTargetJitAbi.Identity)-{command.Suffix}",
-				LegacyOutputDirectory,
+				command.IsNet6 ? Net6OutputDirectory : LegacyOutputDirectory,
 				"@(AndroidSupportedTargetJitAbi)",
 				CmakeBuilds.ConfigureAndroidRuntimeCommandsCommonFlags,
 				command,

build-tools/xaprepare/xaprepare/ConfigAndData/BuildAndroidPlatforms.cs

@@ -42,11 +42,17 @@ class BuildAndroidPlatforms
 			new AndroidPlatform (apiName: "S",                      apiLevel: 31, platformID: "S",   include: "v11.0.99",   framework: "v11.0.99", stable: false),
 		};
 
+		// These are here until we can drop "legacy" targets and use only .NET6+
+		public const string AndroidArmV7a_NET6 = AbiNames.TargetJit.AndroidArmV7a + "_NET6";
+		public const string AndroidArmV8a_NET6 = AbiNames.TargetJit.AndroidArmV8a + "_NET6";
+		public const string AndroidX86_NET6    = AbiNames.TargetJit.AndroidX86 + "_NET6";
+		public const string AndroidX86_64_NET6 = AbiNames.TargetJit.AndroidX86_64 + "_NET6";
+
 		public static readonly Dictionary<string, uint> NdkMinimumAPI = new Dictionary<string, uint> {
-			{ AbiNames.TargetJit.AndroidArmV7a, 16 },
-			{ AbiNames.TargetJit.AndroidArmV8a, 21 },
-			{ AbiNames.TargetJit.AndroidX86,    16 },
-			{ AbiNames.TargetJit.AndroidX86_64, 21 },
+			{ AbiNames.TargetJit.AndroidArmV7a, 16 }, { AndroidArmV7a_NET6, 21 },
+			{ AbiNames.TargetJit.AndroidArmV8a, 21 }, { AndroidArmV8a_NET6, 21 },
+			{ AbiNames.TargetJit.AndroidX86,    16 }, { AndroidX86_NET6, 21 },
+			{ AbiNames.TargetJit.AndroidX86_64, 21 }, { AndroidX86_64_NET6, 21 },
 		};
 	}
 }