Fix the debugger for strict-mode functions.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index c6b26493ce9bcdf709248177842db4348d6736be..6ecc852ee243a3b51c173d5ab2b0bc124fdf656f 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -10299,12 +10299,12 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFrameDetails) {
   // THIS MUST BE DONE LAST SINCE WE MIGHT ADVANCE
   // THE FRAME ITERATOR TO WRAP THE RECEIVER.
   Handle<Object> receiver(it.frame()->receiver(), isolate);
-  if (!receiver->IsJSObject()) {
-    // If the receiver is NOT a JSObject we have hit an optimization
-    // where a value object is not converted into a wrapped JS objects.
-    // To hide this optimization from the debugger, we wrap the receiver
-    // by creating correct wrapper object based on the calling frame's
-    // global context.
+  if (!receiver->IsJSObject() && !receiver->IsUndefined()) {

[Vyacheslav Egorov (Chromium), 2011/07/15 12:43:13]

I think we should check for strict || builtin function instead. Receivers of all
other functions should be wrapped.

I think we have general problem with non-jsobject receivers for strict
functions.

function f() { "use strict"; debugger; }
f.apply("x");

will display this as String object in the debugger while it is actually a
primitive. (But it will not crash).

[Mads Ager (chromium), 2011/07/15 16:32:10]

D'oh! You are absolutely right. Thank you. :-)

That change requires a couple of extra changes as well because the receiver can
now be primitive values as well as undefined and objects.

+    // If the receiver is not a JSObject and is not undefined we have
+    // hit an optimization where a value object is not converted into
+    // a wrapped JS objects. To hide this optimization from the
+    // debugger, we wrap the receiver by creating correct wrapper
+    // object based on the calling frame's global context.
     it.Advance();
     Handle<Context> calling_frames_global_context(
         Context::cast(Context::cast(it.frame()->context())->global_context()));