Use --opt-cross-module only for assemblies within the servicing bubble (#77900)

Author: JoeRobich

src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Microsoft.CodeAnalysis.LanguageServer.csproj

@@ -82,6 +82,26 @@
     </PropertyGroup>
   </Target>
 
+  <Target Name="AddCrossAssemblyOptimizationSwitch"
+    DependsOnTargets="ResolveProjectReferences"
+    AfterTargets="ResolveProjectReferences">
+    <!-- We used to use - -opt-cross-module:* as a switch, but inlining code
+         from the runtime led to exposing bugs in crossgen/runtime in not rejecting
+         native code when the inlined code was stale.
+         To avoid customer facing bugs in C# extension, we are now taking the more
+         conservative approach of only inlining code from assemblies in the same
+         "servicing bubble", which we can most closely approximate here by just
+         inlining code in assemblies that come from project references. -->
+    <ItemGroup>
+      <_OptCrossModuleSwitch
+        Condition="'%(_ResolvedProjectReferencePaths.ReferenceOutputAssembly)'=='true'"
+        Include="@(_ResolvedProjectReferencePaths->'--opt-cross-module:%(FileName)')" />
+    </ItemGroup>
+    <PropertyGroup>
+      <PublishReadyToRunCrossgen2ExtraArgs>$(PublishReadyToRunCrossgen2ExtraArgs);@(_OptCrossModuleSwitch)</PublishReadyToRunCrossgen2ExtraArgs>
+    </PropertyGroup>
+  </Target>
+
   <ItemGroup Label="Project References">
     <ProjectReference Include="..\..\Workspaces\MSBuild\Core\Microsoft.CodeAnalysis.Workspaces.MSBuild.csproj" />
     <ProjectReference Include="..\..\Workspaces\Remote\Core\Microsoft.CodeAnalysis.Remote.Workspaces.csproj" />