[wasm] Only SNPrintF the function index if a name was not supplied.

src/wasm/wasm-objects.cc

 // 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.
 
 #include "src/wasm/wasm-objects.h"
 #include "src/utils.h"
 
 #include "src/debug/debug-interface.h"
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-module.h"
@@ skipping 294 matching lines @@
   DCHECK_EQ(Code::JS_TO_WASM_FUNCTION,
             JSFunction::cast(object)->code()->kind());
   // TODO(titzer): brand check for WasmExportedFunction.
   return reinterpret_cast<WasmExportedFunction*>(object);
 }
 
 Handle<WasmExportedFunction> WasmExportedFunction::New(
     Isolate* isolate, Handle<WasmInstanceObject> instance,
     MaybeHandle<String> maybe_name, int func_index, int arity,
     Handle<Code> export_wrapper) {
-  ScopedVector<char> buffer(16);
-  int length = SNPrintF(buffer, "%d", func_index);
   Handle<String> name;
   if (maybe_name.is_null()) {
+    EmbeddedVector<char, 16> buffer;
+    int length = SNPrintF(buffer, "%d", func_index);
     name = isolate->factory()
                ->NewStringFromAscii(
                    Vector<const char>::cast(buffer.SubVector(0, length)))
                .ToHandleChecked();
   } else {
     name = maybe_name.ToHandleChecked();
   }
   DCHECK_EQ(Code::JS_TO_WASM_FUNCTION, export_wrapper->kind());
   Handle<SharedFunctionInfo> shared =
       isolate->factory()->NewSharedFunctionInfo(name, export_wrapper, false);
@@ skipping 418 matching lines @@
       !array->get(kPreviousInstanceWrapper)->IsFixedArray())
     return false;
   return true;
 }
 
 void WasmInstanceWrapper::set_instance_object(Handle<JSObject> instance,
                                               Isolate* isolate) {
   Handle<WeakCell> cell = isolate->factory()->NewWeakCell(instance);
   set(kWrapperInstanceObject, *cell);
 }