Simplify workaround for UnmanagedCallersOnly

Author: lewing

src/mono/sample/wasi/native/Program.cs

@@ -17,24 +17,15 @@ public static int MyExport(int number)
     [DllImport("*", EntryPoint = "UnmanagedFunc")]
     public static extern void MyImport(); // calls ManagedFunc aka MyExport
 
-    [DllImport("*")]
-    public static unsafe extern void ReferenceFuncPtr(delegate* unmanaged<int,int> funcPtr);
-
-    static bool AlwaysFalse(string [] args) => false;
-
     public unsafe static int Main(string[] args)
     {
         Console.WriteLine($"main: {args.Length}");
-        MyImport();
-
-        if (AlwaysFalse(args))
-        {
-            // never called (would an error on wasm) and doesn't actually do anything
-            // but required for wasm_native_to_interp_ftndesc initialization
-            // the lookup happens before main when this is here
-            ReferenceFuncPtr(&MyExport);
+        // workaround to force the interpreter to initialize wasm_native_to_interp_ftndesc for MyExport
+        if (args.Length > 10000) {
+            ((IntPtr)(delegate* unmanaged<int,int>)&MyExport).ToString();
         }
 
+        MyImport();
         return 0;
     }
 }

src/mono/sample/wasi/native/Wasi.Native.Sample.csproj

@@ -7,6 +7,7 @@
     <WasmBuildNative>true</WasmBuildNative>
     <WasmNativeStrip>false</WasmNativeStrip>
     <IsBrowserWasmProject>false</IsBrowserWasmProject>
+    <WasmSingleFileBundle>true</WasmSingleFileBundle>
   </PropertyGroup>
 
   <ItemGroup>

src/mono/sample/wasi/native/local.c

@@ -8,19 +8,4 @@ void UnmanagedFunc()
     printf("UnmanagedFunc calling ManagedFunc\n");
     ret = ManagedFunc(123);
     printf("ManagedFunc returned %d\n", ret);
-}
-
-
-#ifdef PARSING_FUNCTION_POINTERS_IS_SUPPORTED
-/*
- warning WASM0001: Could not get pinvoke, or callbacks for method 'Test::ReferenceFuncPtr' because 'Parsing function pointe
-r types in signatures is not supported.'
-warning WASM0001: Skipping pinvoke 'Test::ReferenceFuncPtr' because 'Parsing function pointer types in signatures is not s
-upported.'
-*/
-typedef int (*ManagedFuncPtr)(int);
-
-void ReferenceFuncPtr(ManagedFuncPtr funcPtr) {
-    printf("ReferenceFuncPtr %p\n", funcPtr);
-}
-#endif
+}