Classes: Add support for stepping through default constructors

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index 7fe9064e989a1e0bd44c1102ea2b8b5025f5dc91..45f465c0efc55fdb7a215c2e9aef4a1d29fe9a22 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1225,7 +1225,31 @@ void Debug::FloodBoundFunctionWithOneShot(Handle<JSFunction> function) {
   if (!bindee.is_null() && bindee->IsJSFunction() &&
       !JSFunction::cast(*bindee)->IsFromNativeScript()) {
     Handle<JSFunction> bindee_function(JSFunction::cast(*bindee));
-    FloodWithOneShot(bindee_function);
+    if (bindee_function->shared()->is_default_constructor()) {
+      FloodDefaultConstructorWithOneShot(bindee_function);
+    } else {
+      FloodWithOneShot(bindee_function);
+    }
+  }
+}
+
+
+void Debug::FloodDefaultConstructorWithOneShot(Handle<JSFunction> function) {
+  DCHECK(function->shared()->is_default_constructor());
+  // Instead of stepping into the function we directly step into the super class
+  // constructor.
+  Isolate* isolate = function->GetIsolate();
+  PrototypeIterator iter(isolate, function);
+  Handle<Object> proto = PrototypeIterator::GetCurrent(iter);
+  if (!proto->IsJSFunction()) return;  // Object.prototype
+  Handle<JSFunction> function_proto = Handle<JSFunction>::cast(proto);
+
+  if (function_proto->shared()->bound()) {

[aandrey, 2014/11/14 19:27:13]

this if-else block is repeated several times below. maybe extract into a
function?

[arv (Not doing code reviews), 2014/11/14 22:02:22]

Done.

+    FloodBoundFunctionWithOneShot(function_proto);
+  } else if (function_proto->shared()->is_default_constructor()) {
+    FloodDefaultConstructorWithOneShot(function_proto);
+  } else if (!function_proto->IsFromNativeScript()) {
+    FloodWithOneShot(function_proto);
   }
 }
 
@@ -1466,6 +1490,8 @@ void Debug::PrepareStep(StepAction step_action,
         Handle<JSFunction> js_function(JSFunction::cast(fun));
         if (js_function->shared()->bound()) {

[aandrey, 2014/11/14 19:27:13]

repeated again

[arv (Not doing code reviews), 2014/11/14 22:02:22]

Done.

           FloodBoundFunctionWithOneShot(js_function);
+        } else if (js_function->shared()->is_default_constructor()) {
+          FloodDefaultConstructorWithOneShot(js_function);
         } else if (!js_function->IsFromNativeScript()) {
           // Don't step into builtins.
           // It will also compile target function if it's not compiled yet.
@@ -1615,6 +1641,8 @@ void Debug::HandleStepIn(Handle<Object> function_obj, Handle<Object> holder,
     if (function->shared()->bound()) {

[aandrey, 2014/11/14 19:27:13]

repeated once more.

[arv (Not doing code reviews), 2014/11/14 22:02:22]

Done.

       // Handle Function.prototype.bind
       FloodBoundFunctionWithOneShot(function);
+    } else if (function->shared()->is_default_constructor()) {
+      FloodDefaultConstructorWithOneShot(function);
     } else if (!function->IsFromNativeScript()) {
       // Don't allow step into functions in the native context.
       if (function->shared()->code() ==

[aandrey, 2014/11/14 19:27:13]

maybe the following apply & call checks should be there in the other places
also?

[arv (Not doing code reviews), 2014/11/14 22:02:22]

This is the only place where we have the holder.

@@ -1632,6 +1660,8 @@ void Debug::HandleStepIn(Handle<Object> function_obj, Handle<Object> holder,
           } else if (js_function->shared()->bound()) {
             // Handle Function.prototype.bind
             FloodBoundFunctionWithOneShot(js_function);
+          } else if (js_function->shared()->is_default_constructor()) {
+            FloodDefaultConstructorWithOneShot(js_function);
           }
         }
       } else {