[V8] Use Function.name for stack frames in v8::StackTrace

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 37020da1559b70828dfceedf5eb75cb32391817b..a0c5dcbbf14bcae1ee5cc3198e096049b3c5e7a2 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -491,6 +491,8 @@ class CaptureStackTraceHelper {
           STATIC_CHAR_VECTOR("scriptNameOrSourceURL"));
     }
     if (options & StackTrace::kFunctionName) {
+      display_name_ = factory()->InternalizeOneByteString(
+          STATIC_CHAR_VECTOR("displayName"));
       function_key_ = factory()->InternalizeOneByteString(
           STATIC_CHAR_VECTOR("functionName"));
     }
@@ -554,8 +556,14 @@ class CaptureStackTraceHelper {
     }
 
     if (!function_key_.is_null()) {
-      Handle<Object> fun_name(fun->shared()->DebugName(), isolate_);
-      JSObject::AddProperty(stack_frame, function_key_, fun_name, NONE);
+      Handle<Object> display_name =
+          JSObject::GetDataProperty(fun, display_name_);
+      if (display_name->IsString()) {
+        JSObject::AddProperty(stack_frame, function_key_, display_name, NONE);

[Yang, 2015/02/12 14:25:36]

Why are we storing this in a separate property, and not under the same
"functionName"? Do we need to preserve the information about where the name
string originates?

[kozy, 2015/02/12 14:46:13]

In output stack frame we store display name or function name in the same
"functionName" property. In function we try receiving display name from current
JS function instance and if there is no this property then we get DebugName from
SharedFunctionInfo. As I understand it, we can have a lot of JS function objects
with different display names from one shared function info with its name.

+      } else {
+        Handle<Object> fun_name(fun->shared()->DebugName(), isolate_);
+        JSObject::AddProperty(stack_frame, function_key_, fun_name, NONE);
+      }
     }
 
     if (!eval_key_.is_null()) {
@@ -585,6 +593,7 @@ class CaptureStackTraceHelper {
   Handle<String> function_key_;
   Handle<String> eval_key_;
   Handle<String> constructor_key_;
+  Handle<String> display_name_;
 };