[liveedit]: fail to patch if target is outside of async function on stack

src/builtins.cc

 // Copyright 2012 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/builtins.h"
 
 #include "src/api-arguments.h"
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/base/ieee754.h"
@@ skipping 4485 matching lines @@
 
 // ES6 section 25.2.1.1 GeneratorFunction (p1, p2, ... , pn, body)
 BUILTIN(GeneratorFunctionConstructor) {
   HandleScope scope(isolate);
   RETURN_RESULT_OR_FAILURE(isolate,
                            CreateDynamicFunction(isolate, args, "function*"));
 }
 
 BUILTIN(AsyncFunctionConstructor) {
   HandleScope scope(isolate);
-  RETURN_RESULT_OR_FAILURE(
-      isolate, CreateDynamicFunction(isolate, args, "async function"));
+  Handle<JSFunction> func;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, func, CreateDynamicFunction(isolate, args, "async function"));
+
+  // Do not lazily compute eval position for AsyncFunction, as they may not be
+  // determined after the function is resumed.
+  Handle<Script> script = handle(Script::cast(func->shared()->script()));
+  int position = script->GetEvalPosition();
+  USE(position);

[Dan Ehrenberg, 2016/06/14 16:36:01]

Should we be doing this for generators as well? Can a generator's execution be
the only JS frame on the stack and meet all of these conditions?

+
+  return *func;
 }
 
 // ES6 section 19.4.1.1 Symbol ( [ description ] ) for the [[Call]] case.
 BUILTIN(SymbolConstructor) {
   HandleScope scope(isolate);
   Handle<Symbol> result = isolate->factory()->NewSymbol();
   Handle<Object> description = args.atOrUndefined(isolate, 1);
   if (!description->IsUndefined(isolate)) {
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, description,
                                        Object::ToString(isolate, description));
@@ skipping 1503 matching lines @@
 BUILTIN_LIST_H(DEFINE_BUILTIN_ACCESSOR_H)
 BUILTIN_LIST_DEBUG_A(DEFINE_BUILTIN_ACCESSOR_A)
 #undef DEFINE_BUILTIN_ACCESSOR_C
 #undef DEFINE_BUILTIN_ACCESSOR_A
 #undef DEFINE_BUILTIN_ACCESSOR_T
 #undef DEFINE_BUILTIN_ACCESSOR_S
 #undef DEFINE_BUILTIN_ACCESSOR_H
 
 }  // namespace internal
 }  // namespace v8