[browser] trimming of LegacyExports with WasmEnableLegacyJsInterop (#83664)

Author: pavelsavara

eng/testing/tests.browser.targets

@@ -41,6 +41,21 @@
     <WasmIncludeFullIcuData>true</WasmIncludeFullIcuData>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(BuildAOTTestsOn)' == 'local'">
+    <!--
+      When building for BuildAOTTestsOnHelix=true, the WasmApp*targets are *not* imported, because
+      they get instead used by the AOT proxy project on helix.
+
+      On the build machine only the regular part of the build is run, which includes trimming. But if
+      WasmApp*targets modify any trimming arguments, then those will not get picked up by this build.
+      For example - linker substitution files used with simd builds.
+
+      So, set those parameters explicitly here.
+      -->
+    <_ExtraTrimmerArgs Condition="'$(WasmEnableLegacyJsInterop)' == 'false'">$(_ExtraTrimmerArgs) --substitutions &quot;$(MonoProjectRoot)\wasm\build\ILLink.Substitutions.LegacyJsInterop.xml&quot;</_ExtraTrimmerArgs>
+  </PropertyGroup>
+
+
   <!-- On CI this is installed as part of pretest, but it should still be installed
        for WBT, and debugger tests -->
   <Import Project="$(MSBuildThisFileDirectory)wasm-provisioning.targets"
@@ -125,11 +140,6 @@
   <PropertyGroup Condition="'$(BuildAOTTestsOnHelix)' == 'true'">
     <!-- wasm targets are not imported at all, in this case, because we run the wasm build on helix -->
   </PropertyGroup>
-  <ItemGroup Condition="'$(BuildAOTTestsOn)' == 'helix'">
-    <TrimmerRootDescriptor
-      Condition="'$(WasmEnableLegacyJsInterop)' == 'true'"
-      Include="$(MonoProjectRoot)\wasm\build\ILLink.Descriptors.LegacyJsInterop.xml" />
-  </ItemGroup>
 
   <PropertyGroup Condition="'$(IsWasmProject)' == 'true' and '$(BuildAOTTestsOnHelix)' != 'true'">
     <WasmBuildOnlyAfterPublish>true</WasmBuildOnlyAfterPublish>

src/installer/pkg/sfx/Microsoft.NETCore.App/Directory.Build.props

@@ -253,7 +253,7 @@
     <PlatformManifestFileEntry Include="emcc-props.json" IsNative="true" />
     <PlatformManifestFileEntry Include="ILLink.Substitutions.WasmIntrinsics.xml" IsNative="true" />
     <PlatformManifestFileEntry Include="ILLink.Substitutions.NoWasmIntrinsics.xml" IsNative="true" />
-    <PlatformManifestFileEntry Include="ILLink.Descriptors.LegacyJsInterop.xml" IsNative="true" />
+    <PlatformManifestFileEntry Include="ILLink.Substitutions.LegacyJsInterop.xml" IsNative="true" />
     <!-- wasi specific -->
     <PlatformManifestFileEntry Include="main.c" IsNative="true" />
     <PlatformManifestFileEntry Include="driver.h" IsNative="true" />

src/libraries/System.Runtime.InteropServices.JavaScript/src/System.Runtime.InteropServices.JavaScript.csproj

@@ -12,10 +12,7 @@
     <FeatureWasmThreads Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(MonoWasmBuildVariant)' == 'multithread'">true</FeatureWasmThreads>
     <WasmEnableLegacyJsInterop Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(WasmEnableLegacyJsInterop)' == ''">true</WasmEnableLegacyJsInterop>
     <DefineConstants Condition="'$(FeatureWasmThreads)' == 'true'" >$(DefineConstants);FEATURE_WASM_THREADS</DefineConstants>
-    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'true'" >$(DefineConstants);ENABLE_LEGACY_JS_INTEROP</DefineConstants>
-    <ILLinkDescriptorsLibraryBuildXml
-      Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(WasmEnableLegacyJsInterop)' == 'true'"
-      >$(MonoProjectRoot)wasm\build\ILLink.Descriptors.LegacyJsInterop.xml</ILLinkDescriptorsLibraryBuildXml>
+    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'false'" >$(DefineConstants);DISABLE_LEGACY_JS_INTEROP</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup>
@@ -66,7 +63,7 @@
   </ItemGroup>
 
   <!-- only include legacy interop when WasmEnableLegacyJsInterop is enabled -->
-  <ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(WasmEnableLegacyJsInterop)' == 'true'">
+  <ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'browser' and '$(WasmEnableLegacyJsInterop)' != 'false'">
     <Compile Include="System\Runtime\InteropServices\JavaScript\Interop\LegacyExports.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Legacy\Runtime.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\Legacy\Array.cs" />

src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptImports.cs

@@ -20,7 +20,7 @@ public static void MarshalPromise(Span<JSMarshalerArgument> arguments)
             }
         }
 
-#if ENABLE_LEGACY_JS_INTEROP
+#if !DISABLE_LEGACY_JS_INTEROP
         #region legacy
 
         public static object GetGlobalObject(string? str = null)

src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/LegacyExports.cs

@@ -2,16 +2,34 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading.Tasks;
 
 namespace System.Runtime.InteropServices.JavaScript
 {
-    // the public methods are protected from trimming by ILLink.Descriptors.LegacyJsInterop.xml
+    internal static unsafe partial class LegacyExportsTrimmingRoot
+    {
+        // the public methods are used from JavaScript, but the trimmer doesn't know about it.
+        // It's protected by DynamicDependencyAttribute on JSFunctionBinding.BindJSFunction.
+        public static void TrimWhenNotWasmEnableLegacyJsInterop()
+        {
+            // if MSBuild property WasmEnableLegacyJsInterop==false this call would be substituted away and LegacyExports would be trimmed.
+            LegacyExports.PreventTrimming();
+        }
+    }
+
     internal static unsafe partial class LegacyExports
     {
+        // the public methods of this class are used from JavaScript, but the trimmer doesn't know about it.
+        // They are protected by LegacyExportsTrimmingRoot.PreventTrimming and JSFunctionBinding.BindJSFunction.
+        [DynamicDependency(DynamicallyAccessedMemberTypes.All, typeof(LegacyExports))]
+        internal static void PreventTrimming()
+        {
+        }
+
         public static void GetCSOwnedObjectByJSHandleRef(nint jsHandle, int shouldAddInflight, out JSObject? result)
         {
             lock (JSHostImplementation.s_csOwnedObjects)

src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSFunctionBinding.cs

@@ -142,8 +142,8 @@ public static void InvokeJS(JSFunctionBinding signature, Span<JSMarshalerArgumen
         /// <exception cref="PlatformNotSupportedException">The method is executed on an architecture other than WebAssembly.</exception>
         // JavaScriptExports need to be protected from trimming because they are used from C/JS code which IL linker can't see
         [DynamicDependency(DynamicallyAccessedMemberTypes.PublicMethods, "System.Runtime.InteropServices.JavaScript.JavaScriptExports", "System.Runtime.InteropServices.JavaScript")]
-        // TODO make this DynamicDependency conditional again, see https://github.com/dotnet/runtime/pull/82826
-        [DynamicDependency(DynamicallyAccessedMemberTypes.PublicMethods, "System.Runtime.InteropServices.JavaScript.LegacyExports", "System.Runtime.InteropServices.JavaScript")]
+        // Same for legacy, but the type could be explicitly trimmed by setting WasmEnableLegacyJsInterop=false which would use ILLink.Descriptors.LegacyJsInterop.xml
+        [DynamicDependency(DynamicallyAccessedMemberTypes.PublicMethods, "System.Runtime.InteropServices.JavaScript.LegacyExportsTrimmingRoot", "System.Runtime.InteropServices.JavaScript")]
         public static JSFunctionBinding BindJSFunction(string functionName, string moduleName, ReadOnlySpan<JSMarshalerType> signatures)
         {
             if (RuntimeInformation.OSArchitecture != Architecture.Wasm)

src/libraries/System.Runtime.InteropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSObject.References.cs

@@ -10,7 +10,7 @@ public partial class JSObject
     {
         internal nint JSHandle;
 
-#if ENABLE_LEGACY_JS_INTEROP
+#if !DISABLE_LEGACY_JS_INTEROP
         internal GCHandle? InFlight;
         internal int InFlightCounter;
 #endif
@@ -21,7 +21,7 @@ internal JSObject(IntPtr jsHandle)
             JSHandle = jsHandle;
         }
 
-#if ENABLE_LEGACY_JS_INTEROP
+#if !DISABLE_LEGACY_JS_INTEROP
         internal void AddInFlight()
         {
             ObjectDisposedException.ThrowIf(IsDisposed, this);

src/libraries/System.Runtime.InteropServices.JavaScript/tests/System.Runtime.InteropServices.JavaScript.Legacy.UnitTests/System.Runtime.InteropServices.JavaScript.Legacy.UnitTests.csproj

@@ -6,10 +6,10 @@
     <WasmXHarnessArgs>$(WasmXHarnessArgs) --engine-arg=--expose-gc --web-server-use-cop</WasmXHarnessArgs>
     <NoWarn>0612</NoWarn>
     <WasmEnableLegacyJsInterop Condition="'$(WasmEnableLegacyJsInterop)' == ''">true</WasmEnableLegacyJsInterop>
-    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'true'">$(DefineConstants);ENABLE_LEGACY_JS_INTEROP</DefineConstants>
+    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'false'">$(DefineConstants);DISABLE_LEGACY_JS_INTEROP</DefineConstants>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(WasmEnableLegacyJsInterop)' == 'true'">
+  <ItemGroup Condition="'$(WasmEnableLegacyJsInterop)' != 'false'">
     <Compile Include="System\Runtime\InteropServices\JavaScript\JavaScriptTests.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\DataViewTests.cs" />
     <Compile Include="System\Runtime\InteropServices\JavaScript\MemoryTests.cs" />

src/libraries/System.Runtime.InteropServices.JavaScript/tests/System.Runtime.InteropServices.JavaScript.UnitTests/System.Runtime.InteropServices.JavaScript.Tests.csproj

@@ -4,8 +4,10 @@
     <TargetFrameworks>$(NetCoreAppCurrent)-browser</TargetFrameworks>
     <TestRuntime>true</TestRuntime>
     <WasmXHarnessArgs>$(WasmXHarnessArgs) --engine-arg=--expose-gc --web-server-use-cop</WasmXHarnessArgs>
-    <WasmEnableLegacyJsInterop Condition="'$(WasmEnableLegacyJsInterop)' == ''">true</WasmEnableLegacyJsInterop>
-    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'true'">$(DefineConstants);ENABLE_LEGACY_JS_INTEROP</DefineConstants>
+    <EnableAggressiveTrimming>true</EnableAggressiveTrimming>
+    <PublishTrimmed>true</PublishTrimmed>
+    <WasmEnableLegacyJsInterop>false</WasmEnableLegacyJsInterop>
+    <DefineConstants Condition="'$(WasmEnableLegacyJsInterop)' == 'false'">$(DefineConstants);DISABLE_LEGACY_JS_INTEROP</DefineConstants>
     <!-- Use following lines to write the generated files to disk. -->
     <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
   </PropertyGroup>

src/libraries/System.Runtime.InteropServices.JavaScript/tests/System.Runtime.InteropServices.JavaScript.UnitTests/System/Runtime/InteropServices/JavaScript/JSImportExportTest.cs

@@ -58,7 +58,7 @@ public unsafe void GlobalThis()
         [Fact]
         public unsafe void DotnetInstance()
         {
-#if ENABLE_LEGACY_JS_INTEROP
+#if !DISABLE_LEGACY_JS_INTEROP
             Assert.True(JSHost.DotnetInstance.HasProperty("MONO"));
             Assert.Equal("object", JSHost.DotnetInstance.GetTypeOfProperty("MONO"));
 #endif