Issue #17291 has been updated by Eregon (Benoit Daloze).


Yeah I don't think a warning is good enough to prevent people overriding it.
It should be an exception if the goal is to prevent overriding it.

I think we should not compromise semantics for optimizations, that usually leads to more complicated semantics that alternative Ruby implementations have to replicate (which is nonsense if those implementations would check it correctly if redefined).
As an example, the optimization for Hash#each_pair led to very confusing semantics where lambdas/Method#to_proc appear to unsplat arguments (they do not, it's just a side effect of the incorrect optimization).

----------------------------------------
Feature #17291: Optimize __send__ call
https://bugs.ruby-lang.org/issues/17291#change-88356

* Author: mrkn (Kenta Murata)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
I made a patch to optimize a `__send__` call. This optimization replaces a `__send__` method call with a call of the method whose name is the first argument of `__send__` method. The patch is available in [this pull-request](https://github.com/ruby/ruby/pull/3720).

By this change, the redefined `__send__` method is no longer called when it is called by a symbol method name. I guess it is no problem because the following warning message is displayed for a long time.

    $ ruby -e 'def __send__; end'
    -e:1: warning: redefining `__send__' may cause serious problems

This proposal introduces two new instructions: `sendsym` and `opt_sendsym_without_block`.  These instructions handle the cases that the first argument of `__send__` method is not a symbol literal.  I think I can combine these two instructions into one if prefered.

This proposal includes the change proposed in #17288.  I'll mark it as a duplicate of this proposal.

I don't handle `send` method in this proposal. The reason is that we need to examine the redefinition of `send` method in the instruction execution time. I want to discuss only `__send__` method in this ticket.

The benchmark result is below:

```
# Iteration per second (i/s)

|                 |compare-ruby|built-ruby|
|:----------------|-----------:|---------:|
|vm_send_sym      |     18.001M|  112.208M|
|                 |           -|     6.23x|
|vm_send_var      |     17.779M|   30.922M|
|                 |           -|     1.74x|
|vm_send_var_alt  |      3.817M|    6.817M|
|                 |           -|     1.79x|
```



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>