Introduce v8::Exception::GetMessage to find location of an error object.

src/api.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/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 6953 matching lines @@
 
 DEFINE_ERROR(RangeError)
 DEFINE_ERROR(ReferenceError)
 DEFINE_ERROR(SyntaxError)
 DEFINE_ERROR(TypeError)
 DEFINE_ERROR(Error)
 
 #undef DEFINE_ERROR
 
 
+Local<Message> Exception::GetMessage(Handle<Value> exception) {
+  i::Handle<i::Object> obj = Utils::OpenHandle(*exception);
+  if (!obj->IsHeapObject()) return Local<Message>();
+  i::Isolate* isolate = i::HeapObject::cast(*obj)->GetIsolate();
+  ENTER_V8(isolate);
+  i::HandleScope scope(isolate);
+  return Utils::MessageToLocal(
+      scope.CloseAndEscape(isolate->CreateMessage(obj, NULL)));
+}
+
+
 Local<StackTrace> Exception::GetStackTrace(Handle<Value> exception) {
   i::Handle<i::Object> obj = Utils::OpenHandle(*exception);
   if (!obj->IsJSObject()) return Local<StackTrace>();
   i::Handle<i::JSObject> js_obj = i::Handle<i::JSObject>::cast(obj);
   i::Isolate* isolate = js_obj->GetIsolate();
   ENTER_V8(isolate);
   return Utils::StackTraceToLocal(isolate->GetDetailedStackTrace(js_obj));
 }
 
 
@@ skipping 764 matching lines @@
   Isolate* isolate = reinterpret_cast<Isolate*>(info.GetIsolate());
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 } }  // namespace v8::internal