perlcc made easy or, how to make a CGI Moose app

Based on recent work on the B::C module, it's now possible to build a working binary which can do away with the majority of startup expense a typical perl program would have.

In this talk, I'll explain:
- What the perlcc compiler does and doesn't do.
- How to setup the perl compiler.
- How to pre-compile a perl script into a binary for faster execution.
- Discuss the common mistakes one makes when building a perl binary and how to work around them.

1. perlcc
or Reducing the startup cost of perl programs.

2. In the beginning…
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/9512/msg00900.html

3. (What’s a modem?)
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/9512/msg00904.html

4. http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/9601/msg00124.html

5. Perl run states
•BEGIN
•Code is always executed as soon as it’s seen.
•UNITCHECK
•Code is run (LIFO) just after each file is compiled
•CHECK
•Code is run LIFO after ALL compilation
•B::C hooks here to do it’s magic
•INIT
•Runs FIFO at beginning of run time
•Does NOT run if module is loaded at runtime.
•END
•Run LIFO after exit()
http://perldoc.perl.org/perlmod.html

7. B.pm
•Compiler backend.
•Allows a Perl program to delve into its own innards
•Used by B::C to generate state information at the end
of the CHECK block

8. O.pm
•Interface to the compiler
•perl -MO=WHATEVA program.pl
•puts program into -c mode
•creates a CHECK block which runs
B::WHATEVA::compile with some info from the
compile process.

9. B::C
•Reduces your compile time to near zero by freezing
state at end of CHECK block
•perl -MO=-qq,C,-O3,-omyprog.c myprog.pl
•captures perl running state and writes out myprog.c
•compiled binary will start at INIT state

10. File handle gotchas
•opening file handles during compile and expecting
them to functon at run time
•BEGIN { open($fh, ‘<‘, ‘/var/log/foo’) or die }
•sub later { while(<$fh>) {…} }
•This also goes for things like numeric handles to
external libaries ( i.e. openssl handles (IO::Socket::SSL)
•https://rt.cpan.org/Public/Bug/Display.html?id=95452

11. What B::C is not

12. Doesn’t speed up your
program.
(mostly)

13. Can’t statically compile in XS
(mostly)

14. Can’t live independent of
libperl
(mostly)

15. What B::C can do

16. Speeds page hit of
traditional CGI apps.
( No running process when idle )

17. Shrink your program memory
size.
•Package removal during C code generation
•COW strings stored as C strings
•duplicates consolidated to 1 string.
•Strings, Arrays, Hashes optimized to perfect size.

18. Reducing your Moose
startup time
(Eventually)
https://code.google.com/p/perl-compiler/issues/detail?id=350
#damnitstevan

19. B::C Time Line
•1995 - Announcement
•1996 - Compiler development started (B, O, B::C)
•1998 - a8581515f - Integrated into core (5.005)
•November 2003 - Perl 5.6.2
•December 2007 - Removed in 5.10.0
•June 2014 - Mostly Stable - 5.14.4

20. Today
•cPanel initiated effort to get B::C working.
•cPanel Perl code can compile and run against 5.14.4
•perlcc script does all the magic now
•perlcc -e ‘print “Hello world”’; ./a.out
•perlcc -o foo foo.pl
•Optimizations (-O1/-O2/-O3)

21. In the Past
$> cpanm B::C
#Installs perlcc into your perl bin directory
$> perl -MO=-qq,C,-O3,-fno-fold,-ot/C-COMPILED/
CORE—io--print.c t/C-COMPILED/CORE—io—print.t
$> perl script/cc_harness -q t/CORE-CPANEL/io/CORE
—io—print.c -o t/CORE-CPANEL/io/CORE—io—print.bin
$> ./t/CORE-CPANEL/io/CORE—io—print.bin

22. Example
$> cpanm B::C
$> perlcc -o foo foo.pl
$> ./foo
Hello World!

23. Tomorrow
•B::C Working on latest perl
•Compiled perl modules to .so files
•Byte Loader?
•B::CC

24. More information?
•irc.perl.org #compiler
•Issues: https://code.google.com/p/perl-compiler/issues/list
•Contribute: https://github.com/rurban/perl-compiler
•master (unstable)
•release (most recently released to CPAN)
•CPAN: https://metacpan.org/pod/B::C
•Me: Todd Rinaldo <[email protected]>