[monodroid] Build the Xamarin.Android runtime for net6 (#5665)

Context: dotnet/runtime#48416
Context: dotnet/runtime#44505
Context: #5537

Update the `src/monodroid` build system to build the native
Xamarin.Android runtime libraries (e.g. `libmono-android.debug.so`)
against the MonoVM shipped from the `dotnet/runtime` repository in
the `Microsoft.NETCore.App.Runtime.*` NuGet packages.  These NuGet
packages also contain the header files needed to access and use
MonoVM's embedding API.

We thus ~double the number of libraries built by `src/monodroid`,
with one set of builds against the "legacy" Mono, using Mono from the
SDK archives, and another set of builds against .NET 6 MonoVM.

This change requires the introduction of new target directories in
`$(XAInstallPrefix)xbuild/Xamarin/Android/lib` (e.g.
`bin/Debug/lib/xamarin.android/xbuild/Xamarin/Android/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 native runtime libraries:

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

Mono runtime libraries are *not* copied from their respective NuGet
packages; the .NET 6 NuGet packages are required to obtain them.
Compared to the "legacy" builds, we are missing the 
libMonoPosixHelper.so` library.  This helper lib will eventually be
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][0].

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

The `libmono-android.*.so` native libraries no longer need to export
any entry points for P/Invoke purposes.  Instead, the new
`PINVOKE_OVERRIDE` [runtime property][1] is used to hook into the
P/Invoke lookup process.  This allows us to not only hide the public
symbols, but also to remove the `libxa-internal-api.so`
library (d583b7c) completely.

[0]: https://github.com/mono/mono.posix
[1]: https://docs.microsoft.com/en-us/dotnet/core/tutorials/netcore-hosting#step-3---prepare-runtime-properties

.external

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

.gitmodules

@@ -35,6 +35,10 @@
     url = https://github.com/Guardsquare/proguard.git
     branch = master
     ignore = dirty
+[submodule "external/robin-map"]
+    path = external/robin-map
+    url = https://github.com/Tessil/robin-map.git
+    branch = master
 [submodule "external/sqlite"]
     path = external/sqlite
     url = https://github.com/xamarin/sqlite.git

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 },
 		};
 	}
 }