mirror of
https://github.com/ruby/ruby.git
synced 2022-11-09 12:17:21 -05:00
9ddfd2ca00
Object Shapes is used for accessing instance variables and representing the
"frozenness" of objects. Object instances have a "shape" and the shape
represents some attributes of the object (currently which instance variables are
set and the "frozenness"). Shapes form a tree data structure, and when a new
instance variable is set on an object, that object "transitions" to a new shape
in the shape tree. Each shape has an ID that is used for caching. The shape
structure is independent of class, so objects of different types can have the
same shape.
For example:
```ruby
class Foo
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
class Bar
def initialize
# Starts with shape id 0
@a = 1 # transitions to shape id 1
@b = 1 # transitions to shape id 2
end
end
foo = Foo.new # `foo` has shape id 2
bar = Bar.new # `bar` has shape id 2
```
Both `foo` and `bar` instances have the same shape because they both set
instance variables of the same name in the same order.
This technique can help to improve inline cache hits as well as generate more
efficient machine code in JIT compilers.
This commit also adds some methods for debugging shapes on objects. See
`RubyVM::Shape` for more details.
For more context on Object Shapes, see [Feature: #18776]
Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: Eileen M. Uchitelle <eileencodes@gmail.com>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
|
||
|---|---|---|
| .. | ||
| ext | ||
| fixtures | ||
| shared | ||
| array_spec.rb | ||
| basic_object_spec.rb | ||
| bignum_spec.rb | ||
| binding_spec.rb | ||
| boolean_spec.rb | ||
| class_spec.rb | ||
| complex_spec.rb | ||
| constants_spec.rb | ||
| data_spec.rb | ||
| debug_spec.rb | ||
| encoding_spec.rb | ||
| enumerator_spec.rb | ||
| exception_spec.rb | ||
| fiber_spec.rb | ||
| file_spec.rb | ||
| fixnum_spec.rb | ||
| float_spec.rb | ||
| gc_spec.rb | ||
| globals_spec.rb | ||
| hash_spec.rb | ||
| integer_spec.rb | ||
| io_spec.rb | ||
| kernel_spec.rb | ||
| language_spec.rb | ||
| marshal_spec.rb | ||
| module_spec.rb | ||
| mutex_spec.rb | ||
| numeric_spec.rb | ||
| object_spec.rb | ||
| proc_spec.rb | ||
| rake_helper.rb | ||
| range_spec.rb | ||
| rational_spec.rb | ||
| rbasic_spec.rb | ||
| README | ||
| regexp_spec.rb | ||
| spec_helper.rb | ||
| st_spec.rb | ||
| string_spec.rb | ||
| struct_spec.rb | ||
| symbol_spec.rb | ||
| thread_spec.rb | ||
| time_spec.rb | ||
| tracepoint_spec.rb | ||
| typed_data_spec.rb | ||
| util_spec.rb | ||
C-API Specs
These specs test the C-API from Ruby. The following are conventions for the
specs:
1. Put specs for functions related to a Ruby class in a file named according
to the class. For example, for rb_ary_new function, put the specs in
optional/capi/array_spec.rb
2. Put the C file containing the C functions for array_spec.rb in
optional/capi/ext/array_spec.c
3. Name the C extension class 'CApiArraySpecs'.
4. Name the C functions 'array_spec_rb_ary_new'.
5. Attach the C function to the class using the name 'rb_ary_new'