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Bug #8543

Updated by nobu (Nobuyoshi Nakada) over 10 years ago

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. 
 1) Convert code to array 

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

 2. 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. 

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