[ruby-core:121103] [Ruby master Feature#21140] Add a method to get the address of certain JIT related functions

Issue #21140 has been updated by maximecb (Maxime Chevalier-Boisvert).


I'm skeptical of the idea of having third-party JITs as gems. This is exposing a ton of internal APIs that were not previously exposed, which could be potentially problematic if people start to rely on them. You have to think that random gems that are not actually JITs could begin to use these APIs.

I can't stop you from making this change, but Ruby has a history of merging new features too fast without carefully considering the full implications. This is going to sound cynical, but Ruby is not your personal side-project, it's a piece of software that millions of people rely on. If you want a playground to build a JIT and have fun, why not build your own implementation of Lox from Crafting Interpreters or fork an existing one? I'm sorry if this sounds harsh, but I think we all need to ponder merging big changes really carefully. You too should at least try to play the devil's advocate here. What are the downsides?

My two biggest concerns:
1. The additional maintenance burden of random gems relying on internal APIs they shouldn't rely on. Think of the JIT challenges we run into with people abusing binding now. The Ruby public API surface is already too big imo.

2. What does this mean for security? If you have access to these APIs from Rubyland you can potentially take control of the Ruby VM. Is access to these internal APIs restricted somehow?

----------------------------------------
Feature #21140: Add a method to get the address of certain JIT related functions
https://bugs.ruby-lang.org/issues/21140#change-112023

* Author: tenderlovemaking (Aaron Patterson)
* Status: Open
----------------------------------------
Feature #21116 extracted RJIT as a gem. But RJIT accesses certain internal functions which it cannot access as a gem.  For example it used the `rb_str_bytesize` function, but this symbol is not exported, so we cannot access it (even from a C extension).

Instead of exporting these symbols, I would like to propose an API for getting access to their addresses in Ruby.

For example

```ruby
RubyVM::RJIT.address_of(:rb_str_bytesize) # => 123456
```

I would like to limit the addresses to [this list](https://github.com/ruby/ruby/blob/f32d5071b7b01f258eb45cf533496d82d5c0f6a1/tool/rjit/bindgen.rb#L510-L578) which are the ones required by RJIT.



-- 
https://bugs.ruby-lang.org/
 ______________________________________________
 ruby-core mailing list -- [e-mail]
 To unsubscribe send an email to [e-mail]
 ruby-core info -- https://ml.ruby-lang.org/mailman3/lists/ruby-core.ml.ruby-lang.org/