3 files changed, 20 insertions, 0 deletions
diff --git a/src/tools/wasm-split/split-options.cpp b/src/tools/wasm-split/split-options.cpp
index bd6d6f09a..b5929aad7 100644
--- a/src/tools/wasm-split/split-options.cpp
+++ b/src/tools/wasm-split/split-options.cpp
@@ -191,6 +191,15 @@ WasmSplitOptions::WasmSplitOptions()
            placeholderNamespace = argument;
          })
     .add(
+      "--asyncify",
+      "",
+      "Transform the module to support unwinding the stack from placeholder "
+      "functions and rewinding it once the secondary module has been loaded.",
+      WasmSplitOption,
+      {Mode::Split},
+      Options::Arguments::Zero,
+      [&](Options* o, const std::string& argument) { asyncify = true; })
+    .add(
       "--export-prefix",
       "",
       "An identifying prefix to prepend to new export names created "
diff --git a/src/tools/wasm-split/split-options.h b/src/tools/wasm-split/split-options.h
index d52f215cd..16e7b75e6 100644
--- a/src/tools/wasm-split/split-options.h
+++ b/src/tools/wasm-split/split-options.h
@@ -43,6 +43,7 @@ struct WasmSplitOptions : ToolOptions {
   bool emitBinary = true;
   bool symbolMap = false;
   bool placeholderMap = false;
+  bool asyncify = false;
 
   // TODO: Remove this. See the comment in wasm-binary.h.
   bool emitModuleNames = false;
diff --git a/src/tools/wasm-split/wasm-split.cpp b/src/tools/wasm-split/wasm-split.cpp
index 2732502ad..871d6bc95 100644
--- a/src/tools/wasm-split/wasm-split.cpp
+++ b/src/tools/wasm-split/wasm-split.cpp
@@ -280,6 +280,16 @@ void splitModule(const WasmSplitOptions& options) {
   adjustTableSize(wasm, options.initialTableSize);
   adjustTableSize(*secondary, options.initialTableSize);
 
+  // Run asyncify on the primary module
+  if (options.asyncify) {
+    PassOptions passOptions;
+    passOptions.optimizeLevel = 1;
+    passOptions.arguments.insert({"asyncify-ignore-imports", ""});
+    PassRunner runner(&wasm, passOptions);
+    runner.add("asyncify");
+    runner.run();
+  }
+
   if (options.symbolMap) {
     writeSymbolMap(wasm, options.primaryOutput + ".symbols");
     writeSymbolMap(*secondary, options.secondaryOutput + ".symbols");