[ruby-core:66451] [ruby-trunk - Feature #8543] rb_iseq_load

Issue #8543 has been updated by Eric Wong.


 Sorry, the inline patch was an extremely hacky work-in-progress,
 but I think [e-mail] should've been OK with your
 (non keyword) use cases.
 
 Here is a slightly less broken, but still hacky work-in-progress:
   http://80x24.org/spew/m/[e-mail]
   http://80x24.org/spew/m/[e-mail]
 
 This is on top of r48554, which was purely a cleanup commit in
 preparation for this.
 
 Notable changes since v1 (and my WIP v2):
 - iseq#to_ary dumps :kwbits => iseq->params.keyword->bits_start
 
 Current hacks:
 
 * peephole optimization seems to be not idempotent wrt jump elimination
   A second pass (optimize => to_ary => load(optimize) eliminates
   extra useless jumps such as:
 
       jump LABEL
     LABEL:
 
   I currently disable peephole optimization to on load to avoid
   running the optimizer twice, but ideally, the first pass should
   eliminate the above jump insn.
 
 * iseq->stack_size seems not calculated correctly upon load,
   so I'm currently blindly loading it from the misc hash :x

----------------------------------------
Feature #8543: rb_iseq_load
https://bugs.ruby-lang.org/issues/8543#change-50074

* Author: Alexey Voskov
* Status: Open
* Priority: Low
* Assignee: Koichi Sasada
* Category: YARV
* Target version: current: 2.2.0
----------------------------------------
I noticed an unusual behaviour of undocumented rb_iseq_load function. 
Its work differs in different Ruby versions. I'm trying to protect some Ruby
source code by its conversion to YARV p-code and using the next strategy:

1. Convert code to array

   ~~~ruby
   data = RubyVM::InstructionSequence.compile_file('hello.rb').to_a
   ~~~

2. Pass a compiled source to the rb_iseq_load function and evaluate it

   ~~~ruby
   iseq = iseq_load.(data)
   iseq.eval
   ~~~

Sample programs are supplied in the attachments.
"hello.rb"

```ruby
puts "tralivali"
def funct(a,b)
  a**b
end

3.times { |i|
  puts "Hello, world#{funct(2,i)}!"
}
```

The differences
Ruby 1.9.3 (ruby 1.9.3p194 (2012-04-20) [i386-mingw32])
Correct work. Output:

```
tralivali
Hello, world1!
Hello, world2!
Hello, world4!
```

Ruby 2.0.0 (ruby 2.0.0p193 (2013-05-14) [x64-mingw32])
Incorrect work (omits the code inside code blocks). Output

```
tralivali
```

Attempts of loading bigger programs by means of rb_iseq_load in Ruby 2.0.0 usually ends with a segmentation fault.

Such behaviour also can be reproduced by means of iseq Ruby extension ("for iseq freaks")
https://github.com/wanabe/iseq

P.S. I understand that it is an undocumented feature.


---Files--------------------------------
hello.rb (102 Bytes)
rb_pack.rb (931 Bytes)
iseq-load-test3.rb (210 Bytes)
iseq-load-test3-file.rb (369 Bytes)
please-fix-rb_iseq_load-thank-you.pdf (444 KB)


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