dotnet · jkotas · Nov 29, 2020 · Nov 25, 2020 · Nov 27, 2020 · Nov 28, 2020
diff --git a/README.md b/README.md
@@ -1,6 +1,6 @@
 # .NET Runtime - Native AOT
 
-This branch contains experimental fork of CoreCLR [.NET runtime](http://github.com/dotnet/runtime) optimized for the [Native AOT Form factor](https://github.com/dotnet/designs/blob/main/accepted/2020/form-factors.md#native-aot-form-factors). The ahead-of-time (AOT) toolchain can compile .NET application into a native (architecture specific) single-file executable. It can also produce standalone dynamic or static libraries that can be consumed by applications written in other programming languages.
+This branch contains experimental fork of CoreCLR [.NET runtime](http://github.com/dotnet/runtime) optimized for the [Native AOT Form factor](https://github.com/dotnet/designs/blob/main/accepted/2020/form-factors.md#native-aot-form-factors). The ahead-of-time (AOT) toolchain can compile .NET application into a native (architecture specific) single-file executable. It can also produce standalone dynamic or static libraries that can be consumed by applications written in other programming languages.  This branch contains the experimental feature of compiling to LLVM to target Web Assembly at present and other LLVM targets in the future.
 
 ## Samples
 

diff --git a/docs/workflow/building/coreclr/nativeaot.md b/docs/workflow/building/coreclr/nativeaot.md
@@ -10,6 +10,12 @@ The Native AOT toolchain can be currently built for Linux, macOS and Windows x64
    - Add the package directory to your `nuget.config` file. For example, replace `dotnet-experimental` line in `samples\HelloWorld\nuget.config` with `<add key="local" value="C:\runtimelab\artifacts\packages\Debug\Shipping" />`
    - Run `dotnet publish --packages pkg -r [win-x64|linux-x64|osx-64] -c [Debug|Release]` to publish your project. `--packages pkg` option restores the package into a local directory that is easy to cleanup once you are done. It avoids polluting the global nuget cache with your locally built dev package.
 
+## Building for Web Assembly
+- Currently only tested on Windows
+- Run `build nativeaot+libs+nativeaot.packages -rc [Debug|Release] -lc [Debug|Release] -a wasm -os Browser -runtimeFlavor CoreCLR`
+- Add the package directory to your `nuget.config` as above.
+- Run `dotnet publish -r browser-wasm -c [Debug|Release] /p:Platform=wasm` to publish.
+
 ## Visual Studio Solutions
 
 The repository has a number of Visual Studio Solutions files (`*.sln`) that are useful for editing parts of the repository. Build the repo from command line first before building using the solution files. Remember to select the appropriate configuration that you built. By default, `build.cmd` builds Debug x64 and so `Debug` and `x64` must be selected in the solution build configuration drop downs.

diff --git a/eng/Configurations.props b/eng/Configurations.props
@@ -123,9 +123,9 @@
     <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'linux-musl' and $(TargetArchitecture.StartsWith('arm')) and !$(_hostArch.StartsWith('arm'))">linux-x64</_toolRuntimeRID>
 
     <!-- There are no WebAssembly tools, so use the default ones -->
-    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser' and '$(TargetOS)' == 'windows'">win-x64</_toolRuntimeRID>
-    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser' and '$(TargetOS)' != 'windows' and $(_buildingInOSX)">osx-x64</_toolRuntimeRID>
-    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser' and '$(TargetOS)' != 'windows' and !$(_buildingInOSX)">linux-x64</_toolRuntimeRID>
+    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser'">linux-x64</_toolRuntimeRID>
+    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser' and $([MSBuild]::IsOSPlatform('WINDOWS'))">win-x64</_toolRuntimeRID>
+    <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'browser' and $([MSBuild]::IsOSPlatform('OSX'))">osx-x64</_toolRuntimeRID>
 
     <!-- There are no Android tools, so use the default ones -->
     <_toolRuntimeRID Condition="'$(_runtimeOS)' == 'android' and '$(TargetOS)' == 'windows'">win-x64</_toolRuntimeRID>

diff --git a/eng/Subsets.props b/eng/Subsets.props
@@ -237,7 +237,7 @@
   </ItemGroup>
 
   <!-- Mono sets -->
-  <ItemGroup Condition="$(_subset.Contains('+mono.llvm+')) or '$(TargetOS)' == 'iOS' or '$(TargetOS)' == 'tvOS' or '$(TargetOS)' == 'Browser'">
+  <ItemGroup Condition="$(_subset.Contains('+mono.llvm+')) or '$(TargetOS)' == 'iOS' or '$(TargetOS)' == 'tvOS' or ('$(TargetOS)' == 'Browser' and '$(RuntimeFlavor)' != 'CoreCLR')">
     <ProjectToBuild Include="$(MonoProjectRoot)llvm\llvm-init.proj" Category="mono" />
   </ItemGroup>
 

diff --git a/eng/build.ps1 b/eng/build.ps1
@@ -243,7 +243,11 @@ foreach ($config in $configuration) {
   $argumentsWithConfig = $arguments + " -configuration $((Get-Culture).TextInfo.ToTitleCase($config))";
   foreach ($singleArch in $arch) {
     $argumentsWithArch =  "/p:TargetArchitecture=$singleArch " + $argumentsWithConfig
-    $env:__DistroRid="win-$singleArch"
+    if ($singleArch -eq "wasm") {
+        $env:__DistroRid="browser-wasm"
+    } else {
+        $env:__DistroRid="win-$singleArch"
+    }
     Invoke-Expression "& `"$PSScriptRoot/common/build.ps1`" $argumentsWithArch"
     if ($lastExitCode -ne 0) {
         $failedBuilds += "Configuration: $config, Architecture: $singleArch"

diff --git a/eng/liveBuilds.targets b/eng/liveBuilds.targets
@@ -159,22 +159,22 @@
         $(LibrariesNativeArtifactsPath)*.pdb"
         IsNative="true"
         Exclude="@(ExcludeNativeLibrariesRuntimeFiles)" />
-      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser'"
+      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser' and '$(RuntimeFlavor)' == 'Mono'"
                              Include="
         $(LibrariesNativeArtifactsPath)dotnet.js;
         $(LibrariesNativeArtifactsPath)dotnet.wasm;
         $(LibrariesNativeArtifactsPath)dotnet.timezones.blat;
         $(LibrariesNativeArtifactsPath)*.dat;"
         IsNative="true" />
-      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser'"
+      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser' and '$(RuntimeFlavor)' == 'Mono'"
                              Include="
         $(LibrariesNativeArtifactsPath)src\*.c;
         $(LibrariesNativeArtifactsPath)src\*.js;
         $(LibrariesNativeArtifactsPath)src\emcc-flags.txt;
         $(LibrariesNativeArtifactsPath)src\emcc-version.txt;"
         NativeSubDirectory="src"
         IsNative="true" />
-      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser'"
+      <LibrariesRuntimeFiles Condition="'$(TargetOS)' == 'Browser' and '$(RuntimeFlavor)' == 'Mono'"
                              Include="
         $(LibrariesNativeArtifactsPath)include\wasm\*.h;"
         NativeSubDirectory="include\wasm"

diff --git a/eng/native/configurecompiler.cmake b/eng/native/configurecompiler.cmake
@@ -218,6 +218,10 @@ elseif (CLR_CMAKE_HOST_ARCH_ARM64)
   set(ARCH_HOST_NAME arm64)
   add_definitions(-DHOST_ARM64)
   add_definitions(-DHOST_64BIT)
+elseif (CLR_CMAKE_TARGET_ARCH_WASM)
+  set(ARCH_HOST_NAME wasm)
+  add_definitions(-DHOST_WASM=1)
+  add_definitions(-DFEATURE_64BIT_ALIGNMENT=1)
 else ()
   clr_unknown_arch()
 endif ()
@@ -287,22 +291,37 @@ elseif (CLR_CMAKE_TARGET_ARCH_I386)
     set(ARCH_TARGET_NAME x86)
     set(ARCH_SOURCES_DIR i386)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:TARGET_X86>)
+elseif (CLR_CMAKE_TARGET_ARCH_WASM)
+    set(ARCH_TARGET_NAME wasm) 
+    set(ARCH_SOURCES_DIR wasm)
+    add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:TARGET_WASM>)
 else ()
     clr_unknown_arch()
 endif ()
 
 #--------------------------------------
 # Compile Options
 #--------------------------------------
-if (CLR_CMAKE_HOST_UNIX)
-  # Disable frame pointer optimizations so profilers can get better call stacks
-  add_compile_options(-fno-omit-frame-pointer)
-
+if (NOT(MSVC))
   # The -fms-extensions enable the stuff like __if_exists, __declspec(uuid()), etc.
   add_compile_options(-fms-extensions)
   #-fms-compatibility      Enable full Microsoft Visual C++ compatibility
   #-fms-extensions         Accept some non-standard constructs supported by the Microsoft compiler
 
+  # Disabled common warnings
+  add_compile_options(-Wno-unused-variable)
+  add_compile_options(-Wno-unused-value)
+  add_compile_options(-Wno-unused-function)
+  add_compile_options(-Wno-tautological-compare)
+
+  #These seem to indicate real issues
+  add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-Wno-invalid-offsetof>)
+endif (NOT(MSVC))
+
+if (CLR_CMAKE_HOST_UNIX)
+  # Disable frame pointer optimizations so profilers can get better call stacks
+  add_compile_options(-fno-omit-frame-pointer)
+
   # Make signed arithmetic overflow of addition, subtraction, and multiplication wrap around
   # using twos-complement representation (this is normally undefined according to the C++ spec).
   add_compile_options(-fwrapv)
@@ -322,20 +341,11 @@ if (CLR_CMAKE_HOST_UNIX)
     add_compile_options(-Werror)
   endif(PRERELEASE)
 
-  # Disabled common warnings
-  add_compile_options(-Wno-unused-variable)
-  add_compile_options(-Wno-unused-value)
-  add_compile_options(-Wno-unused-function)
-  add_compile_options(-Wno-tautological-compare)
-
   check_cxx_compiler_flag(-Wimplicit-fallthrough COMPILER_SUPPORTS_W_IMPLICIT_FALLTHROUGH)
   if (COMPILER_SUPPORTS_W_IMPLICIT_FALLTHROUGH)
     add_compile_options(-Wimplicit-fallthrough)
   endif()
 
-  #These seem to indicate real issues
-  add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-Wno-invalid-offsetof>)
-
   if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     # The -ferror-limit is helpful during the porting, it makes sure the compiler doesn't stop
     # after hitting just about 20 errors.
@@ -639,6 +649,8 @@ if (CLR_CMAKE_HOST_WIN32)
         message(FATAL_ERROR "MC not found")
     endif()
 
+elseif(CLR_CMAKE_TARGET_ARCH_WASM)
+    # No other tools required, emcmake is already running this script
 else (CLR_CMAKE_HOST_WIN32)
     enable_language(ASM)
 

diff --git a/eng/native/configureplatform.cmake b/eng/native/configureplatform.cmake
@@ -183,7 +183,8 @@ if(CLR_CMAKE_HOST_OS STREQUAL Windows)
 endif(CLR_CMAKE_HOST_OS STREQUAL Windows)
 
 if(CLR_CMAKE_HOST_OS STREQUAL Emscripten)
-    #set(CLR_CMAKE_HOST_UNIX 1) # TODO: this should be reenabled but it activates a bunch of additional compiler flags in configurecompiler.cmake
+    set(CLR_CMAKE_HOST_WIN32 0)
+    set(CLR_CMAKE_HOST_UNIX 0)
     set(CLR_CMAKE_HOST_UNIX_WASM 1)
     set(CLR_CMAKE_HOST_BROWSER 1)
 endif(CLR_CMAKE_HOST_OS STREQUAL Emscripten)
@@ -337,8 +338,10 @@ endif(CLR_CMAKE_TARGET_OS STREQUAL SunOS)
 
 if(CLR_CMAKE_TARGET_OS STREQUAL Emscripten)
     set(CLR_CMAKE_TARGET_UNIX 1)
-    set(CLR_CMAKE_TARGET_LINUX 1)
     set(CLR_CMAKE_TARGET_BROWSER 1)
+    if(NOT(RUNTIME_FLAVOR STREQUAL CoreClr))
+        set(CLR_CMAKE_TARGET_LINUX 1)
+    endif(NOT(RUNTIME_FLAVOR STREQUAL CoreClr))
 endif(CLR_CMAKE_TARGET_OS STREQUAL Emscripten)
 
 if(CLR_CMAKE_TARGET_UNIX)
@@ -364,7 +367,7 @@ endif(CLR_CMAKE_TARGET_UNIX)
 # check if host & target os/arch combination are valid
 if (CLR_CMAKE_TARGET_OS STREQUAL CLR_CMAKE_HOST_OS)
     if(NOT(CLR_CMAKE_TARGET_ARCH STREQUAL CLR_CMAKE_HOST_ARCH))
-        if(NOT((CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_ARM64) OR (CLR_CMAKE_HOST_ARCH_I386 AND CLR_CMAKE_TARGET_ARCH_ARM) OR (CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_ARM) OR (CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_I386)))
+        if(NOT((CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_ARM64) OR (CLR_CMAKE_HOST_ARCH_I386 AND CLR_CMAKE_TARGET_ARCH_ARM) OR (CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_ARM) OR (CLR_CMAKE_HOST_ARCH_AMD64 AND CLR_CMAKE_TARGET_ARCH_I386) OR (CLR_CMAKE_TARGET_UNIX_WASM AND CLR_CMAKE_HOST_ARCH STREQUAL Windows_NT)))
             message(FATAL_ERROR "Invalid platform and target arch combination TARGET_ARCH=${CLR_CMAKE_TARGET_ARCH} HOST_ARCH=${CLR_CMAKE_HOST_ARCH}")
         endif()
     endif()

diff --git a/eng/native/gen-buildsys.cmd b/eng/native/gen-buildsys.cmd
@@ -29,7 +29,7 @@ if /i "%__Ninja%" == "1" (
     if /i NOT "%__Arch%" == "wasm" (
         if /i "%__VSVersion%" == "vs2019" (set __CmakeGenerator=%__CmakeGenerator% 16 2019)
         if /i "%__VSVersion%" == "vs2017" (set __CmakeGenerator=%__CmakeGenerator% 15 2017)
-        
+
         if /i "%__Arch%" == "x64" (set __ExtraCmakeParams=%__ExtraCmakeParams% -A x64)
         if /i "%__Arch%" == "arm" (set __ExtraCmakeParams=%__ExtraCmakeParams% -A ARM)
         if /i "%__Arch%" == "arm64" (set __ExtraCmakeParams=%__ExtraCmakeParams% -A ARM64)
@@ -38,17 +38,17 @@ if /i "%__Ninja%" == "1" (
         set __CmakeGenerator=NMake Makefiles
     )
 )
-
+echo gen-buildsys %__Arch%
 if /i "%__Arch%" == "wasm" (
-    if "%EMSDK_PATH%" == "" (
-       echo Error: Should set EMSDK_PATH environment variable pointing to emsdk root.
+    if "%EMSDK%" == "" (
+       echo Error: Should set EMSDK environment variable pointing to emsdk root.
        exit /B 1
     )
 
-    if "%EMSCRIPTEN_ROOT%" == "" (
-      set EMSCRIPTEN_ROOT="%EMSDK_PATH/upstream/emscripten%"
+    if /i "%CMAKE_BUILD_TYPE%" == "debug" (
+        set __ExtraCmakeParams=%__ExtraCmakeParams% -g -O0
     )
-    set __ExtraCmakeParams=%__ExtraCmakeParams% "-DEMSCRIPTEN_GENERATE_BITCODE_STATIC_LIBRARIES=1" "-DCMAKE_TOOLCHAIN_FILE=%EMSCRIPTEN%/cmake/Modules/Platform/Emscripten.cmake"
+    set __ExtraCmakeParams=%__ExtraCmakeParams% "-DCMAKE_BUILD_TYPE=%CMAKE_BUILD_TYPE%" "-DCMAKE_TOOLCHAIN_FILE=%EMSDK%/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake" -DCLR_CMAKE_TARGET_ARCH=wasm -DCLR_CMAKE_TARGET_ARCH_WASM=1 -DCLR_CMAKE_HOST_ARCH=Windows_NT -DCLR_CMAKE_HOST_OS=Emscripten -DRUNTIME_FLAVOR=CoreClr -DCLR_CMAKE_HOST_UNIX_WASM=1 "-DCLR_ENG_NATIVE_DIR=%__repoRoot%\eng\native" "-DCMAKE_REPO_ROOT=%__repoRoot%" -DCLR_CMAKE_KEEP_NATIVE_SYMBOLS=1
     set __UseEmcmake=1
 ) else (
     set __ExtraCmakeParams=%__ExtraCmakeParams%  "-DCMAKE_SYSTEM_VERSION=10.0"

diff --git a/samples/HelloWorld/HelloWorld.csproj b/samples/HelloWorld/HelloWorld.csproj
@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.DotNet.ILCompiler" Version="6.0.0-*" />
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="6.0.0-*" />
   </ItemGroup>
 
 </Project>
diff --git a/samples/HelloWorld/README.md b/samples/HelloWorld/README.md
@@ -33,7 +33,7 @@ This will add a nuget.config file to your application. Open the file and in the
 Once you've added the package source, add a reference to the compiler by running the following command:
 
 ```bash
-> dotnet add package Microsoft.DotNet.ILCompiler -v 6.0.0-*
+> dotnet add package Microsoft.DotNet.ILCompiler.LLVM -v 6.0.0-*
 ```
 
 ## Restore and Publish your app

diff --git a/samples/HelloWorld/nuget.config b/samples/HelloWorld/nuget.config
@@ -3,7 +3,7 @@
  <packageSources>
     <!--To inherit the global NuGet package sources remove the <clear/> line below -->
     <clear />
-    <add key="dotnet-experimental" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-experimental/nuget/v3/index.json" />
+    <add key="local" value="e:\github\runtimelab\artifacts\packages\Debug\Shipping" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
  </packageSources>
 </configuration>
diff --git a/samples/NativeLibrary/NativeLibrary.csproj b/samples/NativeLibrary/NativeLibrary.csproj
@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.DotNet.ILCompiler" Version="6.0.0-*" />
+    <PackageReference Include="Microsoft.DotNet.ILCompiler.LLVM" Version="6.0.0-*" />
   </ItemGroup>
 
 </Project>
diff --git a/src/coreclr/CMakeLists.txt b/src/coreclr/CMakeLists.txt
@@ -75,21 +75,23 @@ if(CLR_CMAKE_HOST_UNIX)
     add_subdirectory(src/pal)
     add_subdirectory(src/hosts)
 else(CLR_CMAKE_HOST_UNIX)
-    if(CLR_CMAKE_TARGET_UNIX)
+    if(CLR_CMAKE_TARGET_UNIX AND NOT CLR_CMAKE_HOST_UNIX_WASM)
         add_subdirectory(src/pal/src/libunwind)
-    endif(CLR_CMAKE_TARGET_UNIX)
+    endif(CLR_CMAKE_TARGET_UNIX AND NOT CLR_CMAKE_HOST_UNIX_WASM)
 endif(CLR_CMAKE_HOST_UNIX)
 
 # Add this subdir. We install the headers for the jit.
 add_subdirectory(src/pal/prebuilt/inc)
 
-add_subdirectory(src/debug/debug-pal)
+if(NOT CLR_CMAKE_HOST_UNIX_WASM)
+    add_subdirectory(src/debug/debug-pal)
+    add_subdirectory(src/tools/aot/jitinterface)
+endif(NOT CLR_CMAKE_HOST_UNIX_WASM)
 
 if(CLR_CMAKE_TARGET_WIN32 AND CLR_CMAKE_BUILD_SUBSET_RUNTIME)
   add_subdirectory(src/gc/sample)
 endif()
 
-add_subdirectory(src/tools/aot/jitinterface)
 
 if(NOT CLR_CROSS_COMPONENTS_BUILD)
   add_subdirectory(src/nativeaot)

diff --git a/src/coreclr/build-runtime.cmd b/src/coreclr/build-runtime.cmd
@@ -58,6 +58,7 @@ set __BuildArchX64=0
 set __BuildArchX86=0
 set __BuildArchArm=0
 set __BuildArchArm64=0
+set __BuildArchWasm=0
 
 set __BuildTypeDebug=0
 set __BuildTypeChecked=0
@@ -117,6 +118,7 @@ if /i "%1" == "-x64"                 (set __BuildArchX64=1&set processedArgs=!pr
 if /i "%1" == "-x86"                 (set __BuildArchX86=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
 if /i "%1" == "-arm"                 (set __BuildArchArm=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
 if /i "%1" == "-arm64"               (set __BuildArchArm64=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
+if /i "%1" == "-wasm"                (set __BuildArchWasm=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
 
 if /i "%1" == "-debug"               (set __BuildTypeDebug=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
 if /i "%1" == "-checked"             (set __BuildTypeChecked=1&set processedArgs=!processedArgs! %1&shift&goto Arg_Loop)
@@ -233,6 +235,11 @@ if %__BuildArchArm64%==1 (
     set __BuildArch=arm64
     set __CrossArch=x64
 )
+if %__BuildArchWasm%==1 (
+    set __TargetOS=browser
+    set __BuildArch=wasm
+    set __BuildJit=0
+)
 
 set /A __TotalSpecifiedBuildType=__BuildTypeDebug + __BuildTypeChecked + __BuildTypeRelease
 if %__TotalSpecifiedBuildType% GTR 1 (
@@ -622,6 +629,9 @@ if %__BuildNative% EQU 1 (
     if %__Ninja% EQU 1 (
         set __ExtraCmakeArgs="-DCMAKE_BUILD_TYPE=!__BuildType!" 
     )
+    if "%__BuildArch%" == "wasm" (
+        set __ExtraCmakeArgs="-DCMAKE_BUILD_TYPE=!__BuildType!" 
+    )
 
     set __ExtraCmakeArgs=!__ExtraCmakeArgs! !___CrossBuildDefine! %__CMakeClrBuildSubsetArgs% "-DCLR_CMAKE_PGO_INSTRUMENT=%__PgoInstrument%" "-DCLR_CMAKE_OPTDATA_PATH=%__PgoOptDataPath%" "-DCLR_CMAKE_PGO_OPTIMIZE=%__PgoOptimize%" "-DCLR_ENG_NATIVE_DIR=%__RepoRootDir%/eng/native" "-DCLR_REPO_ROOT_DIR=%__RepoRootDir%" %__CMakeArgs%
     call "%__RepoRootDir%\eng\native\gen-buildsys.cmd" "%__ProjectDir%" "%__IntermediatesDir%" %__VSVersion% %__BuildArch% !__ExtraCmakeArgs!
@@ -656,7 +666,10 @@ if %__BuildNative% EQU 1 (
         set __CmakeBuildToolArgs=
     ) else (
         REM We pass the /m flag directly to MSBuild so that we can get both MSBuild and CL parallelism, which is fastest for our builds.
-        set __CmakeBuildToolArgs=/nologo /m !__Logging!
+        REM wasm uses nmake which does not support /m
+        if not "%__BuildArch%" == "wasm" (
+            set __CmakeBuildToolArgs=/nologo /m !__Logging!
+        )
     )
 
     "%CMakePath%" --build %__IntermediatesDir% --target install --config %__BuildType% -- !__CmakeBuildToolArgs!
@@ -671,6 +684,7 @@ if %__BuildNative% EQU 1 (
     )
 
     if /i "%__BuildArch%" == "arm64" goto SkipCopyUcrt
+    if /i "%__BuildArch%" == "wasm" goto SkipCopyUcrt
 
     if not defined UCRTVersion (
         echo %__ErrMsgPrefix%%__MsgPrefix%Error: Please install Windows 10 SDK.

diff --git a/src/coreclr/clrfeatures.cmake b/src/coreclr/clrfeatures.cmake
@@ -2,6 +2,10 @@ if(CLR_CMAKE_TARGET_TIZEN_LINUX)
   set(FEATURE_GDBJIT_LANGID_CS 1)
 endif()
 
+if(CLR_CMAKE_TARGET_UNIX_WASM)
+  set(FEATURE_EVENT_TRACE 0)
+endif()
+
 if(NOT DEFINED FEATURE_EVENT_TRACE)
   set(FEATURE_EVENT_TRACE 1)
 endif(NOT DEFINED FEATURE_EVENT_TRACE)