[ruby-core:65557] [ruby-trunk - Feature #8543] rb_iseq_load

Issue #8543 has been updated by Eric Wong.


 [e-mail] wrote:
 > Sorry to be the squeaky wheel, but I was wondering if there still
 > might be a chance to look into this before 2.2 is released?
 
 Not speaking for the rest of ruby-core, but I welcome occasional
 reminders like these :)
 
 > I attempted a `git bisect` this evening in the hope of narrowing
 > down where the iseq.load problems began -- however I ran into a
 > problem of being unable to build ruby-trunk prior to this patch:
 > 
 > commit 434826c0e9d3e3b48d99a39b7ad7626a6f1ae2eb
 > Author: kazu <kazu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
 > Date:   Wed Jul 31 13:01:57 2013 +0000
 > 
 >     * parse.y: fix build error with bison-3.0.
 > 
 > And unfortunately the iseq.load problem already existed by that
 > point.
 
 Thanks for that data point, it was before I started mucking with iseq.
 Can you try installing/running an older bison?
 
 > (I wonder how best to proceed with the bisect.  I suppose one
 > could write a script to attempt to apply the parse.y patch at
 > each stage...)
 
 Yes.  "git bisect run" is awesome for scripting these things.

----------------------------------------
Feature #8543: rb_iseq_load
https://bugs.ruby-lang.org/issues/8543#change-49317

* 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)


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