Prior to this commit, we were reading and writing ivar index and
shape ID in inline caches in two separate instructions when
getting and setting ivars. This meant there was a race condition
with ractors and these caches where one ractor could change
a value in the cache while another was still reading from it.
This commit instead reads and writes shape ID and ivar index to
inline caches atomically so there is no longer a race condition.
Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
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>
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>
This commit implements Objects on Variable Width Allocation. This allows
Objects with more ivars to be embedded (i.e. contents directly follow the
object header) which improves performance through better cache locality.
Method references is not only able to be marked up as code, also
reflects `--show-hash` option.
The bug that prevented the old rdoc from correctly parsing these
methods was fixed last month.
This uses the superclass table recently introduced to implement fast
inheritance checking between classes (ex. Foo < Bar).
This is almost identical to what we do in class_search_class_ancestor
(as called by rb_obj_is_kind_of) except that we are checking both
directions: ie. both whether Foo < Bar and whether Bar < Foo.
Calling rb_obj_is_kind_of with an ICLASS returns the same result as
calling it with the ICLASS's original Module.
Most of the time we encounter an ICLASS here checking the validity of a
protected method or super call, which we expect to return true (or raise
a slow exception anyways). We can take advantage of this by performing a
fast class inheritance check on the ICLASS's "includer" in hopes that it
returns true.
If the includer class check returns false we still have to fallback to
the full inheritance chain scan for the module's inclusion, but this
should be less common.
Calling rb_obj_is_kind_of with an ICLASS returns the same result as
calling it with the ICLASS's original Module.
Most of the time we encounter an ICLASS here checking the validity of a
protected method or super call, which we expect to return true (or raise
a slow exception anyways). We can take advantage of this by performing a
fast class inheritance check on the ICLASS's "includer" in hopes that it
returns true.
If the includer class check returns false we still have to fallback to
the full inheritance chain scan for the module's inclusion, but this
should be less common.
Previously when checking ancestors, we would walk all the way up the
ancestry chain checking each parent for a matching class or module.
I believe this was especially unfriendly to CPU cache since for each
step we need to check two cache lines (the class and class ext).
This check is used quite often in:
* case statements
* rescue statements
* Calling protected methods
* Class#is_a?
* Module#===
* Module#<=>
I believe it's most common to check a class against a parent class, to
this commit aims to improve that (unfortunately does not help checking
for an included Module).
This is done by storing on each class the number and an array of all
parent classes, in order (BasicObject is at index 0). Using this we can
check whether a class is a subclass of another in constant time since we
know the location to expect it in the hierarchy.
I used this regex:
([A-Za-z]+)\.html#(?:class|module)-[A-Za-z]+-label-([A-Za-z0-9\-\+]+)
And performed a global find & replace for this:
rdoc-ref:$1@$2
[Feature #17881]
Works similarly to `method_added` but for constants.
```ruby
Foo::BAR = 42 # call Foo.const_added(:FOO)
class Foo::Baz; end # call Foo.const_added(:Baz)
Foo.autoload(:Something, "path") # call Foo.const_added(:Something)
```
This is to allow Module subclasses that include modules before
calling super in the subclass's initialize.
Remove rb_module_check_initializable from Module#initialize.
Module#initialize only calls module_exec if a block is passed,
it doesn't have other issues that would cause problems if
called multiple times or with an already initialized module.
Move initialization of super to Module#allocate, though I'm not
sure it is required there. However, it's needed to be removed
from Module#initialize for this to work.
Fixes [Bug #18292]
This provides a significant speedup for symbol, true, false,
nil, and 0-9, class/module, and a small speedup in most other cases.
Speedups (using included benchmarks):
:symbol :: 60%
0-9 :: 50%
Class/Module :: 50%
nil/true/false :: 20%
integer :: 10%
[] :: 10%
"" :: 3%
One reason this approach is faster is it reduces the number of
VM instructions for each interpolated value.
Initial idea, approach, and benchmarks from Eric Wong. I applied
the same approach against the master branch, updating it to handle
the significant internal changes since this was first proposed 4
years ago (such as CALL_INFO/CALL_CACHE -> CALL_DATA). I also
expanded it to optimize true/false/nil/0-9/class/module, and added
handling of missing methods, refined methods, and RUBY_DEBUG.
This renames the tostring insn to anytostring, and adds an
objtostring insn that implements the optimization. This requires
making a few functions non-static, and adding some non-static
functions.
This disables 4 YJIT tests. Those tests should be reenabled after
YJIT optimizes the new objtostring insn.
Implements [Feature #13715]
Co-authored-by: Eric Wong <e@80x24.org>
Co-authored-by: Alan Wu <XrXr@users.noreply.github.com>
Co-authored-by: Yusuke Endoh <mame@ruby-lang.org>
Co-authored-by: Koichi Sasada <ko1@atdot.net>
Refinement#import_methods imports methods from modules.
Unlike Module#include, it copies methods and adds them into the refinement,
so the refinement is activated in the imported methods.
[Bug #17429] [ruby-core:101639]
When YJIT make calls to routines without reconstructing interpreter
state through jit_prepare_routine_call(), it relies on the routine to
never allocate, raise, and push/pop control frames. Comment about this
on the routines that YJTI calls.
This is probably something we should dynamically verify on debug builds.
It's hard to statically verify this as it requires verifying all
functions in the call tree. Maybe something to look at in the future.
