Add a CMake flag to enable Wasm exceptions in the BinaryenJS build (#5454)

Author: dschuff

CMakeLists.txt

@@ -46,6 +46,9 @@ option(BUILD_EMSCRIPTEN_TOOLS_ONLY "Build only tools needed by emscripten" OFF)
 # Turn this on to build binaryen.js as ES5, with additional compatibility configuration for js_of_ocaml.
 option(JS_OF_OCAML "Build binaryen.js for js_of_ocaml" OFF)
 
+# Turn this on to use the Wasm EH feature instead of emscripten EH in the wasm/BinaryenJS builds
+option(EMSCRIPTEN_ENABLE_WASM_EH "Enable Wasm EH feature in emscripten build" OFF)
+
 # For git users, attempt to generate a more useful version string
 if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/.git)
   find_package(Git QUIET REQUIRED)
@@ -313,8 +316,12 @@ if(EMSCRIPTEN)
   endif()
 
   add_link_flag("-sALLOW_MEMORY_GROWTH")
-  add_compile_flag("-sDISABLE_EXCEPTION_CATCHING=0")
-  add_link_flag("-sDISABLE_EXCEPTION_CATCHING=0")
+  if(EMSCRIPTEN_ENABLE_WASM_EH)
+    add_compile_flag("-fwasm-exceptions")
+  else()
+    add_compile_flag("-sDISABLE_EXCEPTION_CATCHING=0")
+    add_link_flag("-sDISABLE_EXCEPTION_CATCHING=0")
+  endif()
   # make the tools immediately usable on Node.js
   add_link_flag("-sNODERAWFS")
   # in opt builds, LTO helps so much (>20%) it's worth slow compile times

scripts/test/binaryenjs.py

@@ -60,7 +60,7 @@ def test(cmd):
             test([shared.MOZJS, '-m', 'a.mjs'])
         if shared.NODEJS:
             if node_has_wasm or 'WebAssembly.' not in test_src:
-                test([shared.NODEJS, 'a.mjs'])
+                test([shared.NODEJS, '--experimental-wasm-eh', 'a.mjs'])
             else:
                 print('Skipping ' + test_path + ' because WebAssembly might not be supported')