From: Sean O'Neil Date: 2010-09-16T22:27:08+09:00 Subject: [ruby-core:32429] [Ruby-Bug#3841][Open] RubyVM::InstructionSequence.to_a() and disasm() do not work properly for "for in " Bug #3841: RubyVM::InstructionSequence.to_a() and disasm() do not work properly for "for in " http://redmine.ruby-lang.org/issues/show/3841 Author: Sean O'Neil Status: Open, Priority: Normal Category: core ruby -v: ruby 1.9.2p0 (2010-08-18 revision 29036) [i386-mswin32_90] I have been playing with the concept of caching compiled Ruby instruction sequences and reloading them later. For now the simplest way to do it is to use RubyVM::InstructionSequence.to_a() and Marshal.dump() to convert the resulting array to a smaller binary byte sequence. While testing this, I found that some Ruby scripts worked fine when an instruction sequence was reloaded, but others broke. As a test, I decided to try compiling irb.rb and its dependencies. When I try to reload the compiled sequences, the first file that breaks is irb/extend-command.rb. I tracked it down to the way "for in " code block and parameters are handled, but I am not sure how to fix it. When I converted each "for in " loop to ".each {||", it started working perfectly. Here's an example of how the disassembly differs between the two loops: def self.install_extend_commands @EXTEND_COMMANDS.each {|args| def_extend_command(*args) } end == disasm: == catch table | catch type: redo st: 0000 ed: 0012 sp: 0000 cont: 0000 | catch type: next st: 0000 ed: 0012 sp: 0000 cont: 0012 |------------------------------------------------------------------------ local table (size: 2, argc: 1 [opts: 0, rest: -1, post: 0, block: -1] s3) [ 2] args 0000 trace 1 ( 110) 0002 putnil 0003 getdynamic args, 0 0006 send :def_extend_command, 1, nil, 10, 0012 leave def self.install_extend_commands for args in @EXTEND_COMMANDS def_extend_command(*args) end end == disasm: == catch table | catch type: redo st: 0005 ed: 0016 sp: 0000 cont: 0005 | catch type: next st: 0005 ed: 0016 sp: 0000 cont: 0016 |------------------------------------------------------------------------ local table (size: 2, argc: 1 [opts: 0, rest: -1, post: 0, block: -1] s3) [ 2] ? 0000 getdynamic *, 0 ( 206) 0003 setlocal args ( 204) 0005 trace 1 ( 205) 0007 putnil 0008 getlocal args 0010 send :def_extend_command, 1, nil, 10, 0016 leave In this example, rb_id2name() returns NULL for the name of the argument passed to the code block. That is why it puts a "?" in the local table and a "*" in the getdynamic command. The to_a() method has a similar problem, and it appears to put a number there instead. When I use the load() method to convert the array back into an instruction sequence and try to execute it, the code block ends up receiving a number as a parameter instead of the entry in the list it is supposed to get. I imagine this is not a high priority for the Ruby core team, and I don't mind putting in some work to fix it. However, it looks like it would take me a while to figure out, so I would appreciate any tips you could give me to point me in the right direction. Thank you, Sean O'Neil ---------------------------------------- http://redmine.ruby-lang.org