[One .NET] Enable Profiled AOT by default for Release builds (#6547)

To improve startup performance for `Release` builds on .NET 6+:

 1. Default `$(RunAOTCompilation)` to `true`

 2. Default `$(AndroidEnableProfiledAot)` to `true`.

Going forward, you would have to explicitly turn these off if you
want them to be off.  (You *may* want them to be off if you care more
about `.apk` size than startup perf, as Profiled AOT tends to add
10-20% to the `.apk` size, per ABI.)

We also can drop the `android-aot` workload, and just include the
[dotnet/runtime AOT packs][0] in the `android` workload.  These packs
are already inserted into Visual Studio, so we can rely on them.

Since the new project options screen evaluates MSBuild, we don't
appear to need to do anything on the UI side:

> Code Generation & Runtime
>
> AOT | Enable Ahead-of-Time (AOT) Compilation
> ⬛ Debug
> ✅ Release
>
> Startup Tracing | Enable startup tracing
> ⬛ Debug
> ✅ Release

[0]: https://github.com/dotnet/runtime/blob/c7adf5598f27e59644030ddae4e382cbda74e41e/src/mono/nuget/Microsoft.NET.Workload.Mono.Toolchain.Manifest/WorkloadManifest.json.in#L29-L40

Author: jonathanpeppers

Documentation/guides/OneDotNet.md

@@ -176,6 +176,28 @@ property, as `$(AotAssemblies)` will eventually be deprecated.
 
 [blazor]: https://devblogs.microsoft.com/aspnet/asp-net-core-updates-in-net-6-preview-4/#blazor-webassembly-ahead-of-time-aot-compilation
 
+We want to choose the optimal settings for startup time and app size.
+By default `Release` builds will default to:
+
+```xml
+<PropertyGroup Condition="'$(Configuration)' == 'Release'">
+  <RunAOTCompilation>true</RunAOTCompilation>
+  <AndroidEnableProfiledAot>true</AndroidEnableProfiledAot>
+</PropertyGroup>
+```
+This is the behavior when `$(RunAOTCompilation)` and
+`$(AndroidEnableProfiledAot)` are blank.
+
+So if you would like to *disable* AOT, you would need to explicitly
+turn these settings off:
+
+```xml
+<PropertyGroup Condition="'$(Configuration)' == 'Release'">
+  <RunAOTCompilation>false</RunAOTCompilation>
+  <AndroidEnableProfiledAot>false</AndroidEnableProfiledAot>
+</PropertyGroup>
+```
+
 ## dotnet cli
 
 There are currently a few "verbs" we are aiming to get working in

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

@@ -112,14 +112,14 @@
       <Output TaskParameter="Result" ItemName="_NuGetSources" />
     </XmlPeek>
 
-    <!-- dotnet workload install android-aot -->
+    <!-- dotnet workload install android -->
     <PropertyGroup>
       <_TempDirectory>$(DotNetPreviewPath)..\.xa-workload-temp-$([System.IO.Path]::GetRandomFileName())</_TempDirectory>
     </PropertyGroup>
     <ItemGroup>
       <_NuGetSources Include="$(OutputPath.TrimEnd('\'))" />
       <_PreviewPacks Condition=" '$(AndroidLatestStableApiLevel)' != '$(AndroidLatestUnstableApiLevel)' " Include="$(XamarinAndroidSourcePath)bin\Build$(Configuration)\nuget-unsigned\Microsoft.Android.Ref.$(AndroidLatestUnstableApiLevel).*.nupkg" />
-      <_InstallArguments Include="android-aot" />
+      <_InstallArguments Include="android" />
       <_InstallArguments Include="android-$(AndroidLatestUnstableApiLevel)" Condition=" '@(_PreviewPacks->Count())' != '0' " />
       <_InstallArguments Include="--skip-manifest-update" />
       <_InstallArguments Include="--verbosity diag" />

build-tools/create-packs/vs-workload.in.props

@@ -10,7 +10,6 @@
       <Replacement>@PACK_VERSION_SHORT@</Replacement>
     </ShortNames>
     <ComponentResources Include="android" Version="@WORKLOAD_VERSION@" Category=".NET" Title=".NET SDK for Android" Description=".NET SDK Workload for building Android applications."/>
-    <ComponentResources Include="android-aot" Version="@WORKLOAD_VERSION@" Category=".NET" Title=".NET SDK for Android with AOT" Description=".NET SDK Workload for building Android applications with AOT support."/>
     <WorkloadPackages Include="$(NuGetPackagePath)\Microsoft.NET.Sdk.Android.Manifest*.nupkg" Version="@WORKLOAD_VERSION@" />
   </ItemGroup>
 </Project>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets

@@ -71,9 +71,12 @@
     <AndroidManifest Condition=" '$(AndroidManifest)' == '' and Exists ('Properties\AndroidManifest.xml') and !Exists ('AndroidManifest.xml') ">Properties\AndroidManifest.xml</AndroidManifest>
     <AndroidManifest Condition=" '$(AndroidManifest)' == '' ">AndroidManifest.xml</AndroidManifest>
     <GenerateApplicationManifest Condition=" '$(GenerateApplicationManifest)' == '' ">true</GenerateApplicationManifest>
+    <!-- Default to AOT in Release mode -->
+    <RunAOTCompilation Condition=" '$(RunAOTCompilation)' == '' and '$(AotAssemblies)' == '' and '$(Configuration)' == 'Release' ">true</RunAOTCompilation>
     <RunAOTCompilation Condition=" '$(RunAOTCompilation)' == '' and '$(AotAssemblies)' == 'true' ">true</RunAOTCompilation>
     <RunAOTCompilation Condition=" '$(RunAOTCompilation)' == '' ">false</RunAOTCompilation>
     <AotAssemblies>$(RunAOTCompilation)</AotAssemblies>
+    <AndroidEnableProfiledAot Condition=" '$(AndroidEnableProfiledAot)' == '' and '$(RunAOTCompilation)' == 'true' ">true</AndroidEnableProfiledAot>
 
     <!--
       Runtime libraries feature switches defaults

src/Xamarin.Android.Build.Tasks/Microsoft.NET.Sdk.Android/WorkloadManifest.in.json

@@ -14,12 +14,7 @@
         "Microsoft.Android.Templates"
       ],
       "platforms": [ "win-x64", "linux-x64", "osx-x64", "osx-arm64" ],
-      "extends" : [ "microsoft-net-runtime-android" ]
-    },
-    "android-aot": {
-      "description": ".NET SDK Workload for building Android applications with AOT support.",
-      "platforms": [ "win-x64", "linux-x64", "osx-x64", "osx-arm64" ],
-      "extends" : [ "android", "microsoft-net-runtime-android-aot" ]
+      "extends" : [ "microsoft-net-runtime-android", "microsoft-net-runtime-android-aot" ]
     }
   },
   "packs": {

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest.cs

@@ -132,6 +132,9 @@ public void SmokeTestBuildWithSpecialCharacters ([Values (false, true)] bool for
 				new XamarinAndroidApplicationProject ();
 			proj.ProjectName = testName;
 			proj.IsRelease = true;
+			// TODO: AOT fails https://github.com/xamarin/xamarin-android/issues/6685
+			// .NET 6 uses AOT by default for Release
+			proj.AotAssemblies = false;
 			if (forms) {
 				proj.PackageReferences.Clear ();
 				proj.PackageReferences.Add (KnownPackages.XamarinForms_4_7_0_1142);

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest2.cs

@@ -75,6 +75,7 @@ public void BuildReleaseArm64 ([Values (false, true)] bool forms)
 				new XamarinFormsAndroidApplicationProject () :
 				new XamarinAndroidApplicationProject ();
 			proj.IsRelease = true;
+			proj.AotAssemblies = false; // Release defaults to Profiled AOT for .NET 6
 			proj.SetAndroidSupportedAbis ("arm64-v8a");
 			proj.SetProperty ("LinkerDumpDependencies", "True");
 			proj.SetProperty ("AndroidUseAssemblyStore", "False");

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/XASdkTests.cs

@@ -532,9 +532,7 @@ public void DotNetBuild (string runtimeIdentifiers, bool isRelease, bool aot, bo
 			};
 			proj.MainActivity = proj.DefaultMainActivity.Replace (": Activity", ": AndroidX.AppCompat.App.AppCompatActivity");
 			proj.SetProperty ("AndroidUseAssemblyStore", usesAssemblyStore.ToString ());
-			if (aot) {
-				proj.SetProperty ("RunAOTCompilation", "true");
-			}
+			proj.SetProperty ("RunAOTCompilation", aot.ToString ());
 			proj.OtherBuildItems.Add (new AndroidItem.InputJar ("javaclasses.jar") {
 				BinaryContent = () => ResourceData.JavaSourceJarTestJar,
 			});
@@ -634,6 +632,10 @@ public void DotNetBuild (string runtimeIdentifiers, bool isRelease, bool aot, bo
 				} else {
 					helper.AssertContainsEntry ("assemblies/System.Private.CoreLib.dll",        shouldContainEntry: expectEmbeddedAssembies);
 				}
+				if (aot) {
+					helper.AssertContainsEntry ($"lib/{abi}/libaot-{proj.ProjectName}.dll.so");
+					helper.AssertContainsEntry ($"lib/{abi}/libaot-System.Linq.dll.so");
+				}
 			}
 		}
 

tests/MSBuildDeviceIntegration/Tests/BundleToolTests.cs

@@ -68,6 +68,7 @@ public void OneTimeSetUp ()
 			var bytes = new byte [1024];
 			app = new XamarinFormsMapsApplicationProject {
 				IsRelease = true,
+				AotAssemblies = false, // Release defaults to Profiled AOT for .NET 6
 				PackageName = "com.xamarin.bundletooltests",
 			};
 			app.OtherBuildItems.Add (new AndroidItem.AndroidAsset ("foo.bar") {

tests/MSBuildDeviceIntegration/Tests/InstallAndRunTests.cs

@@ -614,6 +614,7 @@ public void RunWithInterpreterEnabled ([Values (false, true)] bool isRelease)
 
 			proj = new XamarinAndroidApplicationProject () {
 				IsRelease = isRelease,
+				AotAssemblies = false, // Release defaults to Profiled AOT for .NET 6
 			};
 			var abis = new string[] { "armeabi-v7a", "arm64-v8a", "x86", "x86_64" };
 			proj.SetAndroidSupportedAbis (abis);