dotnet · pavelsavara · Nov 7, 2025 · Nov 7, 2025 · Nov 7, 2025 · Nov 7, 2025
diff --git a/eng/native.props b/eng/native.props
diff --git a/eng/native.wasm.targets b/eng/native.wasm.targets
@@ -0,0 +1,78 @@
+<Project>
+  <ItemGroup>
+    <PackageReference Condition="'$(TargetsWasm)' == 'true'" Include="Microsoft.NETCore.Runtime.ICU.Transport" PrivateAssets="all" Version="$(MicrosoftNETCoreRuntimeICUTransportVersion)" GeneratePathProperty="true" />
+    <PackageReference Condition="'$(TargetsWasm)' == 'true'" Include="System.Runtime.TimeZoneData" PrivateAssets="all" Version="$(SystemRuntimeTimeZoneDataVersion)" GeneratePathProperty="true" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <_RuntimeVariant />
+    <_RuntimeVariant Condition="'$(WasmEnableThreads)' == 'true'">-threads</_RuntimeVariant>
+
+    <_IcuDir Condition="'$(PkgMicrosoft_NETCore_Runtime_ICU_Transport)' != '' and '$(TargetsWasm)' == 'true'">$(PkgMicrosoft_NETCore_Runtime_ICU_Transport)/runtimes/$(TargetOS)-$(TargetArchitecture)$(_RuntimeVariant)/native</_IcuDir>
+    <_TzdDir Condition="'$(PkgSystem_Runtime_TimeZoneData)' != '' and '$(TargetsWasm)' == 'true'">$([MSBuild]::NormalizePath('$(PkgSystem_Runtime_TimeZoneData)', 'contentFiles', 'any', 'any', 'data'))</_TzdDir>
+  </PropertyGroup>
+
+  <ItemGroup>
+      <NativeCMakeArg Condition="'$(_IcuDir)' != ''" Include="-cmakeargs &quot;-DCMAKE_ICU_DIR=$(_IcuDir)&quot;" />
+      <NativeCMakeArg Condition="'$(_TzdDir)' != ''" Include="-cmakeargs &quot;-DCMAKE_TZD_DIR=$(_TzdDir)&quot;" />
+      <NativeCMakeArg Condition="'$(RuntimeFlavor)' == 'Mono'" Include="-cmakeargs &quot;-DCLR_CMAKE_RUNTIME_MONO=1&quot;" />
+      <NativeCMakeArg Condition="'$(RuntimeFlavor)' == 'CoreCLR'" Include="-cmakeargs &quot;-DCLR_CMAKE_RUNTIME_CORECLR=1&quot;" />
+      <NativeCMakeArg Include="-cmakeargs &quot;-DCMAKE_PRODUCT_VERSION=$(ProductVersion)&quot;" />
+      <NativeCMakeArg Include="-cmakeargs &quot;-DCMAKE_CONTINUOUS_INTEGRATION_BUILD=$(ContinuousIntegrationBuild)&quot;" />
+      <NativeCMakeArg Include="-cmakeargs &quot;-DCMAKE_NET_CORE_APP_CURRENT_VERSION=$(NetCoreAppCurrentVersion)&quot;" />
+      <NativeCMakeArg Include="-cmakeargs &quot;-DCMAKE_BUILD_LIBRARIES_CONFIGURATION=$(LibrariesConfiguration)&quot;" />
+      <NativeCMakeArg Include="-cmakeargs &quot;-DCMAKE_BUILD_RUNTIME_CONFIGURATION=$(RuntimeConfiguration)&quot;" />
+      <NativeCMakeArg Condition="'$(TargetsBrowser)' == 'true' and '$(RuntimeFlavor)' == 'CoreCLR'" Include="-cmakeargs &quot;-DBUILD_LIBS_NATIVE_BROWSER=1&quot;" />
+  </ItemGroup>
+
+  <Target Name="GenerateEmccExports" Condition="'$(TargetsBrowser)' == 'true'">
+    <ItemGroup>
+      <EmccExportedRuntimeMethod Include="FS" />
+      <EmccExportedRuntimeMethod Include="out" />
+      <EmccExportedRuntimeMethod Include="err" />
+      <EmccExportedRuntimeMethod Include="ccall" />
+      <EmccExportedRuntimeMethod Include="cwrap" />
+      <EmccExportedRuntimeMethod Include="setValue" />
+      <EmccExportedRuntimeMethod Include="getValue" />
+      <EmccExportedRuntimeMethod Include="UTF8ToString" />
+      <EmccExportedRuntimeMethod Include="UTF8ArrayToString" />
+      <EmccExportedRuntimeMethod Include="lengthBytesUTF8" />
+      <EmccExportedRuntimeMethod Include="stringToUTF8Array" />
+      <EmccExportedRuntimeMethod Include="FS_createPath" />
+      <EmccExportedRuntimeMethod Include="FS_createDataFile" />
+      <EmccExportedRuntimeMethod Include="removeRunDependency" />
+      <EmccExportedRuntimeMethod Include="addRunDependency" />
+      <EmccExportedRuntimeMethod Include="addFunction" />
+      <EmccExportedRuntimeMethod Include="safeSetTimeout" />
+      <EmccExportedRuntimeMethod Include="runtimeKeepalivePush" />
+      <EmccExportedRuntimeMethod Include="runtimeKeepalivePop" />
+      <EmccExportedRuntimeMethod Include="maybeExit" />
+      <EmccExportedRuntimeMethod Include="abort" />
+
+      <EmccExportedFunction Include="_free" />
+      <EmccExportedFunction Include="_htons" />
+      <EmccExportedFunction Include="_malloc" />
+      <EmccExportedFunction Include="_sbrk" />
+      <EmccExportedFunction Include="_memalign" />
+      <EmccExportedFunction Include="_posix_memalign" />
+      <EmccExportedFunction Include="_memset" />
+      <EmccExportedFunction Include="_ntohs" />
+      <EmccExportedFunction Include="stackAlloc" />
+      <EmccExportedFunction Include="stackRestore" />
+      <EmccExportedFunction Include="stackSave" />
+      <!-- TODO-WASM hide -->
+      <EmccExportedFunction Include="_GetDotNetRuntimeContractDescriptor" />
+    </ItemGroup>
+    <PropertyGroup>
+      <_EmccExportedRuntimeMethods>@(EmccExportedRuntimeMethod -> '%(Identity)',',')</_EmccExportedRuntimeMethods>
+      <_EmccExportedFunctions>@(EmccExportedFunction -> '%(Identity)',',')</_EmccExportedFunctions>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <NativeCMakeArg Condition="'$(TargetsBrowser)' == 'true'" Include="-cmakeargs &quot;-DCMAKE_EMCC_EXPORTED_RUNTIME_METHODS=$(_EmccExportedRuntimeMethods)&quot;" />
+      <NativeCMakeArg Condition="'$(TargetsBrowser)' == 'true'" Include="-cmakeargs &quot;-DCMAKE_EMCC_EXPORTED_FUNCTIONS=$(_EmccExportedFunctions)&quot;" />
+    </ItemGroup>
+
+  </Target>
+
+</Project>
diff --git a/eng/testing/tests.browser.targets b/eng/testing/tests.browser.targets
@@ -12,6 +12,7 @@
     <EMSDK_PATH Condition="'$(EMSDK_PATH)' == '' and '$(ContinuousIntegrationBuild)' == 'true' and '$(MonoProjectRoot)' != ''">$([MSBuild]::NormalizeDirectory($(BrowserProjectRoot), 'emsdk'))</EMSDK_PATH>
 
     <WasmEmitSymbolMap Condition="'$(WasmEmitSymbolMap)' == ''">true</WasmEmitSymbolMap>
+    <InvariantGlobalization Condition="'$(InvariantGlobalization)' == ''">false</InvariantGlobalization>
 
     <_WasmMainJSFileName Condition="'$(WasmMainJSPath)' != ''">$([System.IO.Path]::GetFileName('$(WasmMainJSPath)'))</_WasmMainJSFileName>
     <_WasmStrictVersionMatch Condition="'$(ContinuousIntegrationBuild)' == 'true'">true</_WasmStrictVersionMatch>
@@ -34,6 +35,9 @@
     <UseSystemResourceKeys Condition="'$(UseSystemResourceKeys)' == ''">false</UseSystemResourceKeys>
     <EventSourceSupport Condition="'$(EventSourceSupport)' == ''">true</EventSourceSupport>
     <NullabilityInfoContextSupport Condition="'$(NullabilityInfoContextSupport)' == ''">true</NullabilityInfoContextSupport>
+
+    <!-- TODO-WASM https://github.com/dotnet/runtime/issues/120248 -->
+    <WasmEnableWebcil Condition="'$(RuntimeFlavor)' == 'CoreCLR'">false</WasmEnableWebcil>
   </PropertyGroup>
 
   <!-- We expect WASM users to indicate they would like to have bigger download size by adding WasmIncludeFullIcuData, -->

diff --git a/eng/testing/workloads-browser.targets b/eng/testing/workloads-browser.targets
@@ -8,7 +8,7 @@
 
   <Target Name="_GetWorkloadsToInstall" DependsOnTargets="_SetPackageVersionForWorkloadsTesting" Returns="@(WorkloadIdForTesting);@(WorkloadCombinationsToInstall)">
     <Error Condition="'$(RIDForWorkload)' == ''" Text="$(RIDForWorkload) is unset" />
-    <ItemGroup>
+    <ItemGroup Condition="'$(RuntimeFlavor)' == 'Mono'">
       <WorkloadIdForTesting Include="wasm-tools;wasm-experimental"
                             ManifestName="Microsoft.NET.Workload.Mono.ToolChain.Current"
                             Variant="latest"
@@ -67,11 +67,15 @@
       </_DefaultRuntimePackNuGetPath>
     </PropertyGroup>
 
-    <ItemGroup>
+    <ItemGroup Condition="'$(RuntimeFlavor)' == 'Mono'">
       <_RuntimePackNugetAvailable Include="$(LibrariesShippingPackagesDir)Microsoft.NETCore.App.Runtime.Mono.$(RIDForWorkload).*$(PackageVersionForWorkloadManifests).nupkg" />
       <_RuntimePackNugetAvailable Include="$(LibrariesShippingPackagesDir)Microsoft.NETCore.App.Runtime.Mono.*.$(RIDForWorkload).*$(PackageVersionForWorkloadManifests).nupkg" />
       <_RuntimePackNugetAvailable Remove="@(_RuntimePackNugetAvailable)" Condition="$([System.String]::new('%(_RuntimePackNugetAvailable.FileName)').EndsWith('.symbols'))" />
     </ItemGroup>
+    <ItemGroup Condition="'$(RuntimeFlavor)' == 'CoreCLR'">
+      <_RuntimePackNugetAvailable Include="$(LibrariesShippingPackagesDir)Microsoft.NETCore.App.Runtime.$(RIDForWorkload).*$(PackageVersionForWorkloadManifests).nupkg" />
+      <_RuntimePackNugetAvailable Remove="@(_RuntimePackNugetAvailable)" Condition="$([System.String]::new('%(_RuntimePackNugetAvailable.FileName)').EndsWith('.symbols'))" />
+    </ItemGroup>
 
     <Error Condition="@(_RuntimePackNugetAvailable -> Count()) != 2 and @(_RuntimePackNugetAvailable -> Count()) != 1"
            Text="Expected to find either one or two in $(LibrariesShippingPackagesDir): @(_RuntimePackNugetAvailable->'%(FileName)%(Extension)')" />
@@ -87,7 +91,7 @@
     </ItemGroup>
 
     <Message
-        Condition="@(_RuntimePackNugetAvailable -> Count()) == 1"
+        Condition="'$(RuntimeFlavor)' == 'Mono' and @(_RuntimePackNugetAvailable -> Count()) == 1"
         Importance="High"
         Text="
       ********************

diff --git a/src/coreclr/hosts/corerun/CMakeLists.txt b/src/coreclr/hosts/corerun/CMakeLists.txt
@@ -62,20 +62,23 @@ else()
                 "${STATIC_LIB_DESTINATION}/libSystem.Native.Browser.js")
             set(JS_SYSTEM_BROWSER_UTILS
                 "${STATIC_LIB_DESTINATION}/libSystem.Browser.Utils.js")
-            set(JS_CORE_RUN_PRE
-                "${CMAKE_CURRENT_SOURCE_DIR}/wasm/libCorerun.pre.js")
+            set(JS_CORE_RUN
+                "${CMAKE_CURRENT_SOURCE_DIR}/wasm/libCorerun.extpost.js")
             set_target_properties(corerun PROPERTIES
-                LINK_DEPENDS "${JS_CORE_RUN_PRE};${JS_SYSTEM_NATIVE_BROWSER};${JS_SYSTEM_BROWSER_UTILS};"
-                LINK_FLAGS "--pre-js ${JS_CORE_RUN_PRE} --js-library ${JS_SYSTEM_NATIVE_BROWSER} --js-library ${JS_SYSTEM_BROWSER_UTILS}"
+                LINK_DEPENDS "${JS_CORE_RUN};${JS_SYSTEM_NATIVE_BROWSER};${JS_SYSTEM_BROWSER_UTILS};"
+                LINK_FLAGS "--js-library ${JS_SYSTEM_NATIVE_BROWSER} --js-library ${JS_SYSTEM_BROWSER_UTILS} --extern-post-js ${JS_CORE_RUN}"
                 RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
             target_link_options(corerun PRIVATE
                 -sEXIT_RUNTIME=0
                 -sINITIAL_MEMORY=134217728
                 -sMAXIMUM_MEMORY=2147483648
                 -sALLOW_MEMORY_GROWTH=1
                 -sSTACK_SIZE=5MB
-                -sEXPORTED_RUNTIME_METHODS=cwrap,ccall,HEAP8,HEAPU8,HEAP16,HEAPU16,HEAP32,HEAPU32,HEAP64,HEAPU64,HEAPF32,HEAPF64,safeSetTimeout,maybeExit,exitJS,abort,lengthBytesUTF8,UTF8ToString,stringToUTF8Array
-                -sEXPORTED_FUNCTIONS=_main,_GetDotNetRuntimeContractDescriptor
+                -sMODULARIZE=1
+                -sEXPORT_ES6=1
+                -sEXPORTED_RUNTIME_METHODS=ENV,${CMAKE_EMCC_EXPORTED_RUNTIME_METHODS}
+                -sEXPORTED_FUNCTIONS=_main,${CMAKE_EMCC_EXPORTED_FUNCTIONS}
+                -sEXPORT_NAME=createDotnetRuntime
                 -sENVIRONMENT=node,shell,web
                 -Wl,-error-limit=0)
 
@@ -96,7 +99,7 @@ else()
                 # If not running in the browser, add
                 # Node.js file system support.
                 target_link_options(corerun PRIVATE
-                    -lnoderawfs.js
+                    -sNODERAWFS=1
                     -lnodefs.js)
             endif()
         endif()

diff --git a/src/coreclr/hosts/corerun/wasm/libCorerun.extpost.js b/src/coreclr/hosts/corerun/wasm/libCorerun.extpost.js
@@ -0,0 +1,43 @@
+//
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+/* eslint-disable no-undef */
+/* eslint-disable space-before-function-paren */
+/* eslint-disable @typescript-eslint/no-unused-vars */
+var fetch = fetch || undefined; var dotnetNativeModuleLoaded = false; var dotnetInternals = null;
+export function selfRun() {
+    const Module = {};
+    const corePreRun = () => {
+        // copy all node/shell env variables to emscripten env
+        if (globalThis.process && globalThis.process.env) {
+            for (const [key, value] of Object.entries(process.env)) {
+                Module.ENV[key] = value;
+            }
+        }
+
+        Module.ENV["DOTNET_SYSTEM_GLOBALIZATION_INVARIANT"] = "true";
+    };
+    Module.preRun = [corePreRun];
+
+    const runtimeApi = {
+        Module,
+        INTERNAL: {},
+        runtimeId: 0,
+        runtimeBuildInfo: {
+            productVersion: "corerun",
+            gitHash: "corerun",
+            buildConfiguration: "corerun",
+            wasmEnableThreads: false,
+            wasmEnableSIMD: true,
+            wasmEnableExceptionHandling: true,
+        },
+    };
+    dotnetInternals = [
+        runtimeApi,
+        [],
+    ];
+
+    createDotnetRuntime(runtimeApi.Module);
+}
+selfRun();
diff --git a/src/coreclr/hosts/corerun/wasm/libCorerun.pre.js b/src/coreclr/hosts/corerun/wasm/libCorerun.pre.js
diff --git a/src/coreclr/runtime.proj b/src/coreclr/runtime.proj
@@ -11,11 +11,11 @@
     <ProjectReference Condition="'$(HasCdacBuildTool)' == 'true'" Include="tools\cdac-build-tool\cdac-build-tool.csproj" ReferenceOutputAssembly="false" GlobalPropertiesToRemove="$(NativeBuildPartitionPropertiesToRemove)" />
   </ItemGroup>
 
-  <Import Project="$(RepositoryEngineeringDir)native.props" />
+  <Import Project="$(RepositoryEngineeringDir)native.wasm.targets" />
   <Import Project="$(RepositoryEngineeringDir)nativepgo.targets" />
 
   <Target Name="BuildRuntime"
-          DependsOnTargets="GetPgoDataPackagePath"
+          DependsOnTargets="GetPgoDataPackagePath;GenerateEmccExports"
           BeforeTargets="Build">
     <ItemGroup>
       <_CMakeArgs Include="$(CMakeArgs)" />