[cleanup] Adding comments to FunctionTemplateInfo

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: Ia86a3344bbe2a7101b4aa633d80f0dc8141882bb
Reviewed-on: https://chromium-review.googlesource.com/557868Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46434}

src/api.cc

@@ -1354,8 +1354,9 @@ static Local<FunctionTemplate> FunctionTemplateNew(
   obj->set_undetectable(false);
   obj->set_needs_access_check(false);
   obj->set_accept_any_receiver(true);
-  if (!signature.IsEmpty())
+  if (!signature.IsEmpty()) {
     obj->set_signature(*Utils::OpenHandle(*signature));
+  }
   obj->set_cached_property_name(
       cached_property_name.IsEmpty()
           ? isolate->heap()->the_hole_value()

src/objects.h

@@ -7044,39 +7044,87 @@ class TemplateInfo: public Struct {
   DISALLOW_IMPLICIT_CONSTRUCTORS(TemplateInfo);
 };
 
-
+// See the api-exposed FunctionTemplate for more information.
 class FunctionTemplateInfo: public TemplateInfo {
  public:
+  // Handler invoked when calling an instance of this FunctionTemplateInfo.
+  // Either CallInfoHandler or Undefined.
   DECL_ACCESSORS(call_code, Object)
+
+  // ObjectTemplateInfo or Undefined, used for the prototype property of the
+  // resulting JSFunction instance of this FunctionTemplate.
   DECL_ACCESSORS(prototype_template, Object)
+
+  // In the case the prototype_template is Undefined we use the
+  // protoype_provider_template to retrieve the instance prototype. Either
+  // contains an ObjectTemplateInfo or Undefined.
   DECL_ACCESSORS(prototype_provider_template, Object)
+
+  // Used to create protoype chains. The parent_template's prototype is set as
+  // __proto__ of this FunctionTemplate's instance prototype. Is either a
+  // FunctionTemplateInfo or Undefined.
   DECL_ACCESSORS(parent_template, Object)
+
+  // Returns an InterceptorInfo or Undefined for named properties.
   DECL_ACCESSORS(named_property_handler, Object)
+  // Returns an InterceptorInfo or Undefined for indexed properties/elements.
   DECL_ACCESSORS(indexed_property_handler, Object)
+
+  // An ObjectTemplateInfo that is used when instantiating the JSFunction
+  // associated with this FunctionTemplateInfo. Contains either an
+  // ObjectTemplateInfo or Undefined. A default instance_template is assigned
+  // upon first instantiation if it's Undefined.
   DECL_ACCESSORS(instance_template, Object)
+
   DECL_ACCESSORS(class_name, Object)
+
+  // If the signature is a FunctionTemplateInfo it is used to check whether the
+  // receiver calling the associated JSFunction is a compatible receiver, i.e.
+  // it is an instance of the signare FunctionTemplateInfo or any of the
+  // receiver's prototypes are.
   DECL_ACCESSORS(signature, Object)
+
+  // Either a CallHandlerInfo or Undefined. If an instance_call_handler is
+  // provided the instances created from the associated JSFunction are marked as
+  // callable.
   DECL_ACCESSORS(instance_call_handler, Object)
+
   DECL_ACCESSORS(access_check_info, Object)
   DECL_ACCESSORS(shared_function_info, Object)
-  DECL_ACCESSORS(js_function, Object)
+
+  // Internal field to store a flag bitfield.
   DECL_INT_ACCESSORS(flag)
 
-  inline int length() const;
-  inline void set_length(int value);
+  // "length" property of the final JSFunction.
+  DECL_INT_ACCESSORS(length)
+
+  // Either the_hole or a private symbol. Used to cache the result on
+  // the receiver under the the cached_property_name when this
+  // FunctionTemplateInfo is used as a getter.
+  DECL_ACCESSORS(cached_property_name, Object)
 
-  // Following properties use flag bits.
+  // Begin flag bits ---------------------
   DECL_BOOLEAN_ACCESSORS(hidden_prototype)
   DECL_BOOLEAN_ACCESSORS(undetectable)
-  // If the bit is set, object instances created by this function
+
+  // If set, object instances created by this function
   // requires access check.
   DECL_BOOLEAN_ACCESSORS(needs_access_check)
+
   DECL_BOOLEAN_ACCESSORS(read_only_prototype)
+
+  // If set, do not create a prototype property for the associated
+  // JSFunction. This bit implies that neither the prototype_template nor the
+  // prototype_provoider_template are instantiated.
   DECL_BOOLEAN_ACCESSORS(remove_prototype)
+
+  // If set, do not attach a serial number to this FunctionTemplate and thus do
+  // not keep an instance boilerplate around.
   DECL_BOOLEAN_ACCESSORS(do_not_cache)
-  DECL_BOOLEAN_ACCESSORS(accept_any_receiver)
 
-  DECL_ACCESSORS(cached_property_name, Object)
+  // If not set an access may be performed on calling the associated JSFunction.
+  DECL_BOOLEAN_ACCESSORS(accept_any_receiver)
+  // End flag bits ---------------------
 
   DECL_CAST(FunctionTemplateInfo)