From: billk@...
Date: 2014-10-09T23:44:17+00:00
Subject: [ruby-core:65574] [ruby-trunk - Feature #8543] rb_iseq_load

Issue #8543 has been updated by B Kelly.


Eric Wong wrote:
>  
>  Thanks for that data point, it was before I started mucking with iseq.
>  Can you try installing/running an older bison?

Good call -- cygwin indeed allowed me to roll back to bison 2.7.x

I wasn't able to fully automate `git bisect` as there was various build
breakage on some of the commits (usually to do with changes in enc and
enc/trans.)

But ultimately, the result of the manual bisect was:

66d247bcb50a29769ff940100223544c125521aa is the first bad commit
commit 66d247bcb50a29769ff940100223544c125521aa
Author: ko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date:   Tue Apr 24 09:20:42 2012 +0000

    * compile.c: fix to output warning when the same literals
      are available as a condition of same case clause.
      And remove infomation ('#n') because we can find duplicated
      condition with explicit line numbers.
      [ruby-core:38343] [Ruby 1.9 - Bug #5068]
    * test/ruby/test_syntax.rb: add a test for above.



    git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@35459 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

:100644 100644 bcde6499fd43af4fc7eae9496d7eb529e52d5465 5f48bda3d2c5787acfc93c7d209964b45b4405bf M  ChangeLog
:100644 100644 508d599d081ddd3676efc513c25f76f00216116b 74982db138d5432f0077c49265e7b177a906ec97 M      compile.c
:040000 040000 b0608f2c1a2b0eaab543fb26ac4c2a78cb9b0c57 4f78f071cacaf4c8da9d8ccfecb027092f94bc54 M  test


My test script was running both Alexey Voskov's "tralivali" test as
well as my segfault test relating to the case statement.

I suspect the above commit is what introduced the case statement-
related segfault.  I'm not sure if it will also relate to Alexey
Voskov's "tralivali" test well, or whether that might be a separate
issue.  (But if the above can be fixed, I'm happy to try another
bisect if other issues remain.)


Thanks & Regards,

Bill


----------------------------------------
Feature #8543: rb_iseq_load
https://bugs.ruby-lang.org/issues/8543#change-49325

* 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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