Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
@@ -244,11 +244,13 @@
     if (!TemporaryWorkarounds && !F.isDeclaration() && F.getName() == "main") {
       Main = &F;
       LLVMContext &C = M.getContext();
-      Type *MainArgTys[] = {PointerType::get(Type::getInt8PtrTy(C), 0),
-                            Type::getInt32Ty(C)};
+      Type *MainArgTys[] = {Type::getInt32Ty(C),
+                            PointerType::get(Type::getInt8PtrTy(C), 0)};
       FunctionType *MainTy = FunctionType::get(Type::getInt32Ty(C), MainArgTys,
                                                /*isVarArg=*/false);
       if (F.getFunctionType() != MainTy) {
+        LLVM_DEBUG(dbgs() << "Found `main` function with incorrect type: "
+                          << *F.getFunctionType() << "\n");
         Value *Args[] = {UndefValue::get(MainArgTys[0]),
                          UndefValue::get(MainArgTys[1])};
         Value *Casted =
Index: llvm/trunk/test/CodeGen/WebAssembly/main-no-args.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/main-no-args.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/main-no-args.ll
@@ -0,0 +1,18 @@
+; RUN: llc < %s -asm-verbose=false -wasm-temporary-workarounds=false | FileCheck %s
+
+; Test main functions with alternate signatures.
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+define void @main() {
+  ret void
+}
+
+; CHECK-LABEL: .L__original_main:
+; CHECK-NEXT: end_function
+
+; CHECK-LABEL: main:
+; CHECK-NEXT: .param i32, i32
+; CHECK-NEXT: .result i32
+; CHECK:      call .L__original_main@FUNCTION
Index: llvm/trunk/test/CodeGen/WebAssembly/main-with-args.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/main-with-args.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/main-with-args.ll
@@ -0,0 +1,16 @@
+; RUN: llc < %s -asm-verbose=false -wasm-temporary-workarounds=false | FileCheck %s
+
+; Test that main function with expected signature is not wrapped
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+define i32 @main(i32 %a, i8** %b) {
+  ret i32 0
+}
+
+; CHECK-LABEL: main:
+; CHECK-NEXT: .param i32, i32
+; CHECK-NEXT: .result i32
+
+; CHECK-NOT: __original_main:
Index: llvm/trunk/test/CodeGen/WebAssembly/main.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/main.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/main.ll
@@ -1,18 +0,0 @@
-; RUN: llc < %s -asm-verbose=false -wasm-temporary-workarounds=false | FileCheck %s
-
-; Test main functions with alternate signatures.
-
-target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
-target triple = "wasm32-unknown-unknown"
-
-define void @main() {
-  ret void
-}
-
-; CHECK-LABEL: .L__original_main:
-; CHECK-NEXT: end_function
-
-; CHECK-LABEL: main:
-; CHECK-NEXT: .param i32, i32
-; CHECK-NEXT: .result i32
-; CHECK:      call .L__original_main@FUNCTION