How To Build MRI n Times Faster

Clang, a compiler front end which you can use instead of gcc, can build MRI: Matz Ruby Implementation, only if you succeeded in avoiding all pitfalls.

Build the latest LLVM and Clang

Mac OS X Snow Leopard has builtin clang command but it's too old to build ruby. First of all, get the latest clang and it's dependency, the latest LLVM.

$ svn checkout http://llvm.org/svn/llvm-project/llvm/trunk llvm && cd llvm/tools && svn checkout http://llvm.org/svn/llvm-project/cfe/trunk clang && cd ..
$ ./configure && time make

Note that it takes really long time. I recommend you not to build before you go away from keyboard for a while but to build before you go to bed.

A simple test

hello.c

#include<stdio.h>
int main() {
  puts("Hello, world!");
  return 0;
}

building on gcc and clang

$ time gcc hello.c -o hello-gcc
!!!        0.34 real         0.01 user         0.03 sys!!!

[%] /private/tmp
$ time ~/src/llvm/Debug+Asserts/bin/clang hello.c -o hello-clang
!!!        0.11 real         0.06 user         0.02 sys!!!

clang is 3 times faster than gcc to build the hello world code. The executable files work samel.

Ruby

On GCC

$ git clone https://github.com/ruby/ruby.git ruby193-gcc
$ cd ruby193-gcc
$ autoconf
$ ./configure --prefix=`pwd`/local --enable-pthread --disable-install-doc --with-out-ext=tk\* --program-suffix=193 --with-readline-dir=/usr/local --with-arch=x86_64
$ time make
...
!!!      214.93 real       191.58 user        23.57 sys!!!

On Clang

$ git clone https://github.com/ruby/ruby.git ruby193
$ cd ruby193
$ ./configure --prefix=`pwd`/local --enable-pthread --disable-install-doc --with-out-ext=tk\* --program-suffix=193 --with-readline-dir=/usr/local PATH=/Users/ujihisa/src/llvm/Debug+Asserts/bin/:$PATH CC=/Users/ujihisa/src/llvm/Debug+Asserts/bin/clang CFLAGS=-Qunused-arguments CPPFLAGS=-Qunused-arguments --with-arch=x86_64
$ time make
!!!      932.06 real       883.44 user        31.09 sys!!!

It took 3 min 34.93 sec by GCC while it took 15 min 32.06 sec by Clang. GCC is 4.34 times faster than Clang to build MRI.

Pitfalls

If you use clang command of Mac OS X Snow Leopard, even though you'll succeed in finishing make ruby 1.9.3, but you cannot do anything by the Ruby.

$ ./local/bin/ruby -ve 1
ruby 1.9.3dev (2011-01-25 trunk 30651) [x86_64-darwin10.6.0]
!!!dyld: lazy symbol binding failed: Symbol not found: _rb_encdb_declare!!!
!!!  Referenced from: /Users/ujihisa/git/ruby193/local/lib/ruby/1.9.1/x86_64-darwin10.6.0/enc/encdb.bundle!!!
!!!  Expected in: flat namespace!!!

!!!dyld: Symbol not found: _rb_encdb_declare!!!
!!!  Referenced from: /Users/ujihisa/git/ruby193/local/lib/ruby/1.9.1/x86_64-darwin10.6.0/enc/encdb.bundle!!!
!!!  Expected in: flat namespace!!!

!!!/Users/ujihisa/git/ruby193/local/lib/ruby/1.9.1/x86_64-darwin10.6.0/enc/encdb.bundle: [BUG] Segmentation fault!!!
!!!ruby 1.9.3dev (2011-01-25 trunk 30651) [x86_64-darwin10.6.0]!!!

!!!-- Control frame information -----------------------------------------------!!!
!!!c:0002 p:-537663266 s:0004 b:0004 l:000003 d:000003 TOP   !!!
!!!c:0001 p:0000 s:0002 b:0002 l:001dd8 d:001dd8 TOP   !!!


!!!-- See Crash Report log file under ~/Library/Logs/CrashReporter or ---------!!!
!!!-- /Library/Logs/CrashReporter, for the more detail of ---------------------!!!
!!!-- C level backtrace information -------------------------------------------!!!

!!!-- Other runtime information -----------------------------------------------!!!

!!!* Loaded script: ./local/bin/ruby!!!

!!!* Loaded features:!!!

!!!    0 enumerator.so!!!

!!![NOTE]!!!
!!!You may have encountered a bug in the Ruby interpreter or extension libraries.!!!
!!!Bug reports are welcome.!!!
!!!For details: http://www.ruby-lang.org/bugreport.html!!!


!!!vimshell: signal 6(SIGABRT) "./local/bin/ruby -ve 1"!!!

Conclusion

You can build Ruby 1.9.3 by Clang. It's 0.23 times faster than building by GCC.

A Contributed Article to Kernel/VM Advent Calendar: VIM=VM

There are two kinds of programmers; one uses Vim and the other uses Emacs. I don't think there are positive counter opinions about that Emacs is not an editor but an environment. On the other hand, there are some opinions that Vim is an editor or not, even though everyone agrees with the fact that vi is an editor. Some people, including the author of this article, claim that Vim is a virtual machine. Here I give you instructions of a Vim plugin shadow.vim instead of explaining why Vim is VM directly.

shadow.vim

The Vim plugin shadow.vim supports wrapping a virtual file with a program automatically with thin configuration.

Here it's a quote from a programmer:

"Nobody knows the Java code you committed is originally written in Scheme."

Usage

Assuming the product is a.pl, create a.pl.shd first.

a.pl (in Vim):

## ruby -e 'puts $<.read.gsub(/$/, ";")'
$a = 1
print($a)

Open a.pl in Vim. The Vim actually shows the contents of a.pl.shd. When you save the file, the command in the first line without ## runs, then the actual a.pl will be the result.

a.pl (actually):

$a = 1;
print($a);

Install

Unarchive the zip file into a directory that is under &rtp of your Vim, which stands for run time path, including ~/.vim dir.

Use Case

Here there are three examples, but you can use more general purposes.

• Commit JavaScript files which was written in CoffeeScript

  • before

        ## coffee -csb
        f = (x) -> x + 1
        print f 10
    
        # vim: set ft=coffee :
    

  • after

        var f;
        f = function(x) {
          return x + 1;
        };
        print(f(10));
    

• Use cpp command before committing Java files.

• Markdown, Haml or something else to HTML

More examples

You can write code in C and save the file as GNU Assembly Language on your Linux automatically, so you can avoid portability.

References

• VIM=VM http://www.slideshare.net/Shougo/vim-presentation-5330807 by Shougo
• http://atnd.org/events/10701