Canvas2D Performance: fix the bottleneck of hasInstance during JS binding -- overloading

Source/bindings/scripts/v8_interface.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 # coding=utf-8
 #
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@@ skipping 735 matching lines @@
     # • an interface type that V implements
     # (Unlike most of these tests, this can return multiple methods, since we
     #  test if it implements an interface. Thus we need a for loop, not a next.)
     # (We distinguish wrapper types from built-in interface types.)
     for idl_type, method in ((idl_type, method)
                              for idl_type, method in idl_types_methods
                              if idl_type.is_wrapper_type):
         test = 'V8{idl_type}::hasInstance({cpp_value}, info.GetIsolate())'.format(idl_type=idl_type.base_type, cpp_value=cpp_value)
         yield test, method
 
+    # all arguments here of wrapper type are checked by resolution (see above),
+    # they should not be check again for [TypeChecking=interface] methods during
+    # args checking. We mark resolution related arguments as type_checked_already
+    # to avoid redundant checking. However, if there are optional argument(s) in
+    # an overloading method, the method will have multiple callers. Resolution
+    # related argument may be not resolved in some callers in this situation.
+    # So, we just mark those resolution associated arguments whose method has
+    # no optional arguments, for safety.
+    for argument, method in arguments_methods:
+        argument['type_checked_already'] = (argument['is_wrapper_type'] and
+                                            method['number_of_required_arguments'] == method['number_of_arguments'])
+
     # 8. Otherwise: if V is any kind of object except for a native Date object,
     # a native RegExp object, and there is an entry in S that has one of the
     # following types at position i of its type list,
     # • an array type
     # • a sequence type
     # ...
     # • a dictionary
     #
     # FIXME:
     # We don't strictly follow the algorithm here. The algorithm says "remove
@@ skipping 137 matching lines @@
             # [ConstructorCallWith=Document]
             has_extended_attribute_value(interface,
                 'ConstructorCallWith', 'Document'),
         'is_call_with_execution_context':
             # [ConstructorCallWith=ExecutionContext]
             has_extended_attribute_value(interface,
                 'ConstructorCallWith', 'ExecutionContext'),
         'is_constructor': True,
         'is_named_constructor': False,
         'is_raises_exception': is_constructor_raises_exception,
+        'number_of_arguments': len(constructor.arguments),
         'number_of_required_arguments':
             number_of_required_arguments(constructor),
     }
 
 
 # [NamedConstructor]
 def named_constructor_context(interface):
     extended_attributes = interface.extended_attributes
     if 'NamedConstructor' not in extended_attributes:
         return None
@@ skipping 210 matching lines @@
         deleter = next(
             method
             for method in interface.operations
             if ('deleter' in method.specials and
                 len(method.arguments) == 1 and
                 str(method.arguments[0].idl_type) == 'DOMString'))
     except StopIteration:
         return None
 
     return property_deleter(deleter)