Code Review: IO7

grujildo · February 6, 2009, 2:12am

tfpt review “/shelveset:IO7;REDMOND\tomat”

Reviewed F2F by Curt.

Includes inherited overloads in CLR method groups
(RubyMethodGroupInfo). Method groups can now comprise of methods that
are declared in multiple derived types. This might be a bit strange
concept for Ruby programmer since “overloads” can only be defined in a C
library in Ruby and all of them in a single class. Some examples how
basic Ruby operations work with CLR inherited overloads:

CLR hierarchy:
class A { void f(int); }
class B : A { void f(int, int); }
class C : B { void f(int, int, int); }

Ruby view:
class A: “f” => MethodGroup { A::f(int) }
class B: “f” => MethodGroup { A::f(int), B::f(int, int) }
class C: “f” => MethodGroup { A::f(int), B::f(int, int), C::f(int, int,
int) }

Following calls work:
C.new.f(1)
C.new.f(1,2)
C.new.f(1,2,3)

In each case, C#f is found and overload resolution based on passed
argument types is performed on overloads contained in C#f group.

If B is monkey-patched

class B
def f; end
end

the new Ruby method hides all overloads in B and above. The Ruby view is
now:

class A: “f” => MethodGroup { A::f(int) }
class B: “f” => RubyMethod
class C: “f” => MethodGroup { C::f(int, int, int) }

It is no longer possible to call A::f, B::f overloads from an instance
of C:
C.new.f(1) # error
C.new.f(1,2) # calls Ruby method
C.new.f(1,2,3) # calls C::f(int,int,int) overload

If we remove B#f, we get to the previous state:

class B
remove_method :f
end

C.new.f(1) # works
C.new.f(1,2) # works
C.new.f(1,2,3) # works

Strangely enough, we can remove “f” again from B - now it would be the
CLR method group “f” (see #2).

Enables removing CLR methods.

If CLR method group “f” is removed from a class (say X) then all CLR
methods “f” that are declared below the first member “f” (in the
inheritance hierarchy) that is not a CLR method group are not accessible
from an instance of X or any of its subclasses. This also means that it
is not possible to remove a method override and call the overridden
method, since the overridden method is removed as well along with the
override. This behavior is consistent with CLR restrictions on virtual
method calls - it is not verifiable to call an overridden virtual method
directly. Although the restriction is unnecessary for non-virtual
new-slot methods, which could be called directly, it makes the semantics
and implementation simpler. Removing a CLR method group just hides all
CLR methods of the same name below the first non-CLR or non-method
member.

Removes some exceptions thrown from Ruby meta-object binders.
Eventually Ruby binders will use “fallback” mechanism instead of
throwing exceptions, this is the first step. Implements a new caching
mechanism for calls to methods that are handled by method_missing.
Moves version tracking from RubyModule to RubyClasses. We don’t need
to track versions of mixins.
Replaces strong references to dependent modules with weak ones. The
number of weak references allocated for tracking class hierarchy
dependencies is exactly equal to the number of classes in the hierarchy.
Each class defines a weak reference pointing to itself and this weak
reference is reused in all lists that track dependency on this class.
Reimplements dynamic site cache invalidation for mixin inclusions.
Previously we invalidated far too many sites that don’t need to be
invalidated. Reduces site cache invalidation rate during RoR startup
phase to 33% of the current value (from 9161 invalidated rules to 3017).

In the table below, the two numbers for each module update operation are
the number of modules whose version is incremented due to the update and
the number of rules that are bound to the old version. Such rules’ tests
are going to be evaluated to false next time they are invoked.

Before:

module

operation

modules

rules

Object

IncludeModules

201

5644

Kernel

SetMethod: require

34

1138

Object

IncludeModules

58

495

Object

IncludeModules

70

382

Object

SetMethod: require

81

317

Kernel

IncludeModules

50

308

Module

SetMethod: append_features

18

254

Enumerable

IncludeModules

9

242

Array

CreateInstanceSingleton

1

59

Module

IncludeModules

46

47

Module

IncludeModules

47

44

Array

IncludeModules

1

32

Object

IncludeModules

81

27

SetMethod: method_added

12

24

Class

SetMethod: inherited

15

19

Set

CreateInstanceSingleton

1

13

Hash

IncludeModules

1

11

Class

IncludeModules

23

11

Array

CreateInstanceSingleton

1

10

String

IncludeModules

1

8

IncludeModules

1

8

IncludeModules

1

7

IncludeModules

1

7

Hash

IncludeModules

1

6

Symbol

IncludeModules

1

6

String

IncludeModules

1

5

IncludeModules

1

5

Integer

IncludeModules

2

4

Inflector

SetMethod: inflections

2

4

IncludeModules

1

4

IncludeModules

1

4

REXML::XMLDecl

CreateInstanceSingleton

1

3

Integer

IncludeModules

2

IncludeModules

1

2

IncludeModules

1

2

RemoveMethodNoEvent

1

String

IncludeModules

1

IncludeModules

1

IncludeModules

1

SetMethod: included

1

IncludeModules

1

SetMethod: new

1

After:

UPDATED:

Object

SetMethod: require

425

1592

UPDATED:

Object

SetMethod: require

200

966

UPDATED:

Module

SetMethod: append_features

135

259

UPDATED:

Array

CreateInstanceSingleton

4

82

UPDATED:

Class

SetMethod: inherited

126

58

UPDATED:

SetMethod: method_added

110

24

UPDATED:

Set

CreateInstanceSingleton

2

13

UPDATED:

Array

CreateInstanceSingleton

5

10

UPDATED:

SetMethod: inherited

1

4

UPDATED:

REXML::XMLDecl

CreateInstanceSingleton

1

3

UPDATED:

SetMethod: inherited

1

2

UPDATED:

RemoveMethodNoEvent

1

UPDATED:

SetMethod: inherited

1

UPDATED:

SetMethod: included

1

UPDATED:

SetMethod: new

1

Further optimizations might include special caching policy for require,
append_features, inherited, method_added and other Ruby “notifications”.

 Fixes various bugs related to the features implemented/improved

and adds bunch of unit tests.

Tomas