Small MessageLocation related refactoring.

src/isolate.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/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 975 matching lines @@
 
   thread_local_top()->rethrowing_message_ = false;
 
   // Notify debugger of exception.
   if (is_catchable_by_javascript(exception)) {
     debug()->OnThrow(exception_handle);
   }
 
   // Generate the message if required.
   if (requires_message && !rethrowing_message) {
-    MessageLocation potential_computed_location;
-    if (location == NULL) {
-      // If no location was specified we use a computed one instead.
-      ComputeLocation(&potential_computed_location);
-      location = &potential_computed_location;
+    MessageLocation computed_location;
+    // If no location was specified we try to use a computed one instead.
+    if (location == NULL && ComputeLocation(&computed_location)) {
+      location = &computed_location;
     }
 
     if (bootstrapper()->IsActive()) {
       // It's not safe to try to make message objects or collect stack traces
       // while the bootstrapper is active since the infrastructure may not have
       // been properly initialized.
       ReportBootstrappingException(exception_handle, location);
     } else {
       Handle<Object> message_obj = CreateMessage(exception_handle, location);
       thread_local_top()->pending_message_obj_ = *message_obj;
@@ skipping 240 matching lines @@
     Handle<String> line =
         Execution::GetStackTraceLine(recv, fun, pos_obj, is_top_level);
     if (line->length() > 0) {
       line->PrintOn(out);
       PrintF(out, "\n");
     }
   }
 }
 
 
-void Isolate::ComputeLocation(MessageLocation* target) {
-  *target = MessageLocation(Handle<Script>(heap_.empty_script()), -1, -1);
+bool Isolate::ComputeLocation(MessageLocation* target) {
   StackTraceFrameIterator it(this);
   if (!it.done()) {
     JavaScriptFrame* frame = it.frame();
     JSFunction* fun = frame->function();
     Object* script = fun->shared()->script();
     if (script->IsScript() &&
         !(Script::cast(script)->source()->IsUndefined())) {
       int pos = frame->LookupCode()->SourcePosition(frame->pc());
       // Compute the location from the function and the reloc info.
       Handle<Script> casted_script(Script::cast(script));
       *target = MessageLocation(casted_script, pos, pos + 1, handle(fun));
+      return true;
     }
   }
+  return false;
 }
 
 
 bool Isolate::ComputeLocationFromException(MessageLocation* target,
                                            Handle<Object> exception) {
   if (!exception->IsJSObject()) return false;
 
   Handle<Name> start_pos_symbol = factory()->error_start_pos_symbol();
   Handle<Object> start_pos = JSReceiver::GetDataProperty(
       Handle<JSObject>::cast(exception), start_pos_symbol);
@@ skipping 12 matching lines @@
   if (!script->IsScript()) return false;
 
   Handle<Script> cast_script(Script::cast(*script));
   *target = MessageLocation(cast_script, start_pos_value, end_pos_value);
   return true;
 }
 
 
 bool Isolate::ComputeLocationFromStackTrace(MessageLocation* target,
                                             Handle<Object> exception) {
-  *target = MessageLocation(Handle<Script>(heap_.empty_script()), -1, -1);
-
   if (!exception->IsJSObject()) return false;
   Handle<Name> key = factory()->stack_trace_symbol();
   Handle<Object> property =
       JSReceiver::GetDataProperty(Handle<JSObject>::cast(exception), key);
   if (!property->IsJSArray()) return false;
   Handle<JSArray> simple_stack_trace = Handle<JSArray>::cast(property);
 
   Handle<FixedArray> elements(FixedArray::cast(simple_stack_trace->elements()));
   int elements_limit = Smi::cast(simple_stack_trace->length())->value();
 
@@ skipping 29 matching lines @@
       return true;
     }
   }
   return false;
 }
 
 
 Handle<JSMessageObject> Isolate::CreateMessage(Handle<Object> exception,
                                                MessageLocation* location) {
   Handle<JSArray> stack_trace_object;
-  MessageLocation potential_computed_location;
   if (capture_stack_trace_for_uncaught_exceptions_) {
     if (IsErrorObject(exception)) {
       // We fetch the stack trace that corresponds to this error object.
       // If the lookup fails, the exception is probably not a valid Error
       // object. In that case, we fall through and capture the stack trace
       // at this throw site.
       stack_trace_object =
           GetDetailedStackTrace(Handle<JSObject>::cast(exception));
     }
     if (stack_trace_object.is_null()) {
       // Not an error object, we capture stack and location at throw site.
       stack_trace_object = CaptureCurrentStackTrace(
           stack_trace_for_uncaught_exceptions_frame_limit_,
           stack_trace_for_uncaught_exceptions_options_);
     }
   }
-  if (!location) {
-    if (!ComputeLocationFromException(&potential_computed_location,
-                                      exception)) {
-      if (!ComputeLocationFromStackTrace(&potential_computed_location,
-                                         exception)) {
-        ComputeLocation(&potential_computed_location);
-      }
-    }
-    location = &potential_computed_location;
+  MessageLocation computed_location;
+  if (location == NULL &&
+      (ComputeLocationFromException(&computed_location, exception) ||
+       ComputeLocationFromStackTrace(&computed_location, exception) ||
+       ComputeLocation(&computed_location))) {
+    location = &computed_location;
   }
 
   return MessageHandler::MakeMessageObject(
       this, MessageTemplate::kUncaughtException, location, exception,
       stack_trace_object);
 }
 
 
 bool Isolate::IsJavaScriptHandlerOnTop(Object* exception) {
   DCHECK_NE(heap()->the_hole_value(), exception);
@@ skipping 1415 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8