[wasm] Throw a type error if an I64 is exported to JS.

test/mjsunit/wasm/ffi-error.js

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 function testCallFFI(ffi) {
@@ skipping 41 matching lines @@
   testCallFFI(ffi);
 });
 
 
 // "fun" should be a JS function.
 assertThrows(function() {
   var ffi = new Object();
   ffi.fun = 0;
   testCallFFI(ffi);
 });
+
+
+(function I64InSignatureThrows() {
+  var builder = new WasmModuleBuilder();
+
+  builder.addMemory(1, 1, true);
+  builder.addFunction("function_with_invalid_signature", kSig_l_ll)
+    .addBody([           // --
+      kExprGetLocal, 0,  // --
+      kExprGetLocal, 1,  // --
+      kExprI64Sub])      // --
+    .exportFunc()
+
+  var module = builder.instantiate();
+
+  assertThrows(function() {
+      module.exports.function_with_invalid_signature(33, 88);
+    }, TypeError);
+})();