[dotnet] Choose the correct runtime library depending on which runtim…

…e we're using.

dotnet/targets/Xamarin.Shared.Sdk.DefaultItems.targets

@@ -11,8 +11,9 @@
     <EnableDefaultmacOSItems Condition=" '$(_PlatformName)' == 'macOS' And '$(EnableDefaultmacOSItems)' == '' ">$(EnableDefaultItems)</EnableDefaultmacOSItems>
     <EnableDefaultMacCatalystItems Condition=" '$(_PlatformName)' == 'MacCatalyst' And '$(EnableDefaultMacCatalystItems)' == '' ">$(EnableDefaultItems)</EnableDefaultMacCatalystItems>
 
-    <UseMonoRuntime Condition=" '$(UseMonoRuntime)' == '' And '$(_PlatformName)' != 'macOS'">true</UseMonoRuntime>
     <UseMonoRuntime Condition=" '$(UseMonoRuntime)' == '' And '$(_PlatformName)' == 'macOS'">false</UseMonoRuntime>
+    <UseMonoRuntime Condition=" '$(UseMonoRuntime)' == '' And '$(_PlatformName)' == 'iOS' And '$(PublishAot)' == 'true'">false</UseMonoRuntime>
+    <UseMonoRuntime Condition=" '$(UseMonoRuntime)' == ''">true</UseMonoRuntime>
   </PropertyGroup>
 
   <ItemGroup>

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -449,9 +449,6 @@
 			<_LinkerCacheDirectory>$([System.IO.Path]::GetFullPath('$(IntermediateOutputPath)linker-cache'))</_LinkerCacheDirectory>
 			<_LinkerCacheDirectory Condition="'$(BuildSessionId)' != ''">$(IntermediateOutputPath)linker-cache</_LinkerCacheDirectory>
 
-			<_XamarinRuntime Condition="'$(UseMonoRuntime)' == 'true'">MonoVM</_XamarinRuntime>
-			<_XamarinRuntime Condition="'$(UseMonoRuntime)' != 'true'">CoreCLR</_XamarinRuntime>
-
 			<!-- TrimMode specifies what the linker will do with framework assemblies -->
 			<TrimMode Condition="'$(_LinkMode)' == 'TrimMode'">$(TrimMode)</TrimMode>
 			<TrimMode Condition="'$(_LinkMode)' == 'None'">copy</TrimMode>
@@ -830,7 +827,11 @@
 
 	<Target Name="_ComputeFrameworkVariables" DependsOnTargets="ResolveRuntimePackAssets;ResolveFrameworkReferences">
 		<PropertyGroup>
-			<_PackageIdInfix Condition="'$(UseMonoRuntime)' == 'true'">Mono.</_PackageIdInfix>
+			<_XamarinRuntime Condition="'$(UseMonoRuntime)' == 'true'">MonoVM</_XamarinRuntime>
+			<_XamarinRuntime Condition="'$(UseMonoRuntime)' != 'true' And '$(PublishAot)' != 'true'">CoreCLR</_XamarinRuntime>
+			<_XamarinRuntime Condition="'$(UseMonoRuntime)' != 'true' And '$(PublishAot)' == 'true'">NativeAOT</_XamarinRuntime>
+
+			<_PackageIdInfix Condition="'$(_XamarinRuntime)' == 'MonoVM'">Mono.</_PackageIdInfix>
 
 			<_MonoNugetPackageId>Microsoft.NETCore.App.Runtime.$(_PackageIdInfix)$(RuntimeIdentifier)</_MonoNugetPackageId>
 			<_XamarinNugetPackageId>Microsoft.$(_PlatformName).Runtime.$(RuntimeIdentifier)</_XamarinNugetPackageId>
@@ -848,8 +849,9 @@
 			<_XamarinRefAssemblyDirectory>$(_XamarinRefPackageDirectory)/ref/net8.0/</_XamarinRefAssemblyDirectory>
 			<_XamarinRefAssemblyPath>$(_XamarinRefAssemblyDirectory)$(_PlatformAssemblyName).dll</_XamarinRefAssemblyPath>
 
-			<_LibPartialStaticRegistrar Condition="'$(UseMonoRuntime)' == 'true'">$(_XamarinNativeLibraryDirectory)/Microsoft.$(_PlatformName).registrar.a</_LibPartialStaticRegistrar>
-			<_LibPartialStaticRegistrar Condition="'$(UseMonoRuntime)' != 'true'">$(_XamarinNativeLibraryDirectory)/Microsoft.$(_PlatformName).registrar.coreclr.a</_LibPartialStaticRegistrar>
+			<_LibPartialStaticRegistrar Condition="'$(_XamarinRuntime)' == 'MonoVM'">$(_XamarinNativeLibraryDirectory)/Microsoft.$(_PlatformName).registrar.a</_LibPartialStaticRegistrar>
+			<_LibPartialStaticRegistrar Condition="'$(_XamarinRuntime)' == 'CoreCLR'">$(_XamarinNativeLibraryDirectory)/Microsoft.$(_PlatformName).registrar.coreclr.a</_LibPartialStaticRegistrar>
+			<_LibPartialStaticRegistrar Condition="'$(_XamarinRuntime)' == 'NativeAOT'">$(_XamarinNativeLibraryDirectory)/Microsoft.$(_PlatformName).registrar.nativeaot.a</_LibPartialStaticRegistrar>
 
 			<_MonoRuntimePackPath>%(_MonoFrameworkReference.RuntimePackPath)/runtimes/$(RuntimeIdentifier)/</_MonoRuntimePackPath>
 		</PropertyGroup>
@@ -864,6 +866,7 @@
 
 	<Target Name="_VerifyValidRuntime">
 		<Error Text="Only CoreCLR is supported on macOS. Set 'UseMonoRuntime=false' to use CoreCLR." Condition="'$(_PlatformName)' == 'macOS' And '$(UseMonoRuntime)' != 'false'" />
+		<Error Text="NativeAOT is currently not supported on $(_PlatformName). Set 'PublishAot=false' to disable NativeAOT." Condition="'$(_XamarinRuntime)' == 'NativeAOT' And '$(_PlatformName)' != 'iOS'" />
 	</Target>
 
 	<PropertyGroup>
@@ -929,7 +932,9 @@
 			<_LibXamarinLinkMode Condition="'$(_LibXamarinLinkMode)' == ''">static</_LibXamarinLinkMode>
 			<_LibXamarinExtension Condition="'$(_LibXamarinLinkMode)' == 'dylib'">dylib</_LibXamarinExtension>
 			<_LibXamarinExtension Condition="'$(_LibXamarinLinkMode)' == 'static'">a</_LibXamarinExtension>
-			<_LibXamarinRuntime Condition="'$(UseMonoRuntime)' != 'true'">-coreclr</_LibXamarinRuntime>
+			<_LibXamarinRuntime Condition="'$(_XamarinRuntime)' == 'MonoVM'"></_LibXamarinRuntime>
+			<_LibXamarinRuntime Condition="'$(_XamarinRuntime)' == 'CoreCLR'">-coreclr</_LibXamarinRuntime>
+			<_LibXamarinRuntime Condition="'$(_XamarinRuntime)' == 'NativeAOT'">-nativeaot</_LibXamarinRuntime>
 			<_LibXamarinDebug Condition="'$(_BundlerDebug)' == 'true'">-debug</_LibXamarinDebug>
 			<_LibXamarinName Condition="'$(_LibXamarinName)' == ''">libxamarin-dotnet$(_LibXamarinRuntime)$(_LibXamarinDebug).$(_LibXamarinExtension)</_LibXamarinName>
 
@@ -1498,7 +1503,7 @@
 			<!-- Ref: https://github.com/xamarin/xamarin-macios/issues/11432 -->
 			<_CreateDumpExecutable
 				Include="@(ResolvedFileToPublish)"
-				Condition=" '$(UseMonoRuntime)' == 'false' And
+				Condition=" '$(_XamarinRuntime)' == 'CoreCLR' And
 				            '%(ResolvedFileToPublish.Filename)' == 'createdump' And
 				            '%(ResolvedFileToPublish.Extension)' == '' And
 				            '%(ResolvedFileToPublish.AssetType)' == 'native' And