3 files changed, 26 insertions, 1 deletions
diff --git a/src/tools/wasm-emscripten-finalize.cpp b/src/tools/wasm-emscripten-finalize.cpp
index f7de3af3f..c01fb00bf 100644
--- a/src/tools/wasm-emscripten-finalize.cpp
+++ b/src/tools/wasm-emscripten-finalize.cpp
@@ -277,6 +277,9 @@ int main(int argc, const char* argv[]) {
   } else {
     // If not standalone wasm then JS is relevant and we need dynCalls.
     generator.generateDynCallThunks();
+    // This is also not needed in standalone mode since standalone mode uses
+    // crt1.c to invoke the main and is aware of __main_argc_argv mangling.
+    generator.renameMainArgcArgv();
   }
 
   // Legalize the wasm, if BigInts don't make that moot.
diff --git a/src/wasm-emscripten.h b/src/wasm-emscripten.h
index 0fca27056..6343c13d7 100644
--- a/src/wasm-emscripten.h
+++ b/src/wasm-emscripten.h
@@ -60,6 +60,12 @@ public:
 
   void enforceStackLimit();
 
+  // clang uses name mangling to rename the argc/argv form of main to
+  // __main_argc_argv.  Emscripten in non-standalone mode expects that function
+  // to be exported as main.  This function renames __main_argc_argv to main
+  // as expected by emscripten.
+  void renameMainArgcArgv();
+
   void exportWasiStart();
 
   // Emits the data segments to a file. The file contains data from address base
diff --git a/src/wasm/wasm-emscripten.cpp b/src/wasm/wasm-emscripten.cpp
index 1d58699ec..c2cace488 100644
--- a/src/wasm/wasm-emscripten.cpp
+++ b/src/wasm/wasm-emscripten.cpp
@@ -1225,7 +1225,11 @@ std::string EmscriptenGlueGenerator::generateEmscriptenMetadata(
   meta << "\n  ],\n";
 
   auto mainReadsParams = false;
-  if (auto* exp = wasm.getExportOrNull("main")) {
+  auto* exp = wasm.getExportOrNull("main");
+  if (!exp) {
+    exp = wasm.getExportOrNull("__main_argc_argv");
+  }
+  if (exp) {
     if (exp->kind == ExternalKind::Function) {
       auto* main = wasm.getFunction(exp->value);
       mainReadsParams = true;
@@ -1268,6 +1272,18 @@ void EmscriptenGlueGenerator::separateDataSegments(Output* outfile,
   wasm.memory.segments.clear();
 }
 
+void EmscriptenGlueGenerator::renameMainArgcArgv() {
+  // If an export call ed __main_argc_argv exists rename it to main
+  Export* ex = wasm.getExportOrNull("__main_argc_argv");
+  if (!ex) {
+    BYN_TRACE("renameMain: __main_argc_argv not found\n");
+    return;
+  }
+  ex->name = "main";
+  wasm.updateMaps();
+  ModuleUtils::renameFunction(wasm, "__main_argc_argv", "main");
+}
+
 void EmscriptenGlueGenerator::exportWasiStart() {
   // If main exists, export a function to call it per the wasi standard.
   Name main = "main";