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B::Bytecode(3)


NAME

  B::Bytecode - Perl compiler's bytecode backend


SYNOPSIS

	  perl -MO=Bytecode[,OPTIONS] foo.pl


DESCRIPTION

  This compiler backend takes Perl source and generates a platform-
  independent bytecode encapsulating code to load the internal structures
  perl uses to run your program. When the generated bytecode is loaded in,
  your program is ready to run, reducing the time which perl would have taken
  to load and parse your program into its internal semi-compiled form. That
  means that compiling with this backend will not help improve the runtime
  execution speed of your program but may improve the start-up time.
  Depending on the environment in which your program runs this may or may not
  be a help.

  The resulting bytecode can be run with a special byteperl executable or
  (for non-main programs) be loaded via the "byteload_fh" function in the B
  module.


OPTIONS

  If there are any non-option arguments, they are taken to be names of
  objects to be saved (probably doesn't work properly yet).  Without extra
  arguments, it saves the main program.

  -ofilename
      Output to filename instead of STDOUT.

  -afilename
      Append output to filename.

  --  Force end of options.

  -f  Force optimisations on or off one at a time. Each can be preceded by
      no- to turn the option off (e.g. -fno-compress-nullops).

  -fcompress-nullops
      Only fills in the necessary fields of ops which have been optimised
      away by perl's internal compiler.

  -fomit-sequence-numbers
      Leaves out code to fill in the op_seq field of all ops which is only
      used by perl's internal compiler.

  -fbypass-nullops
      If op->op_next ever points to a NULLOP, replaces the op_next field with
      the first non-NULLOP in the path of execution.

  -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.  -O1 sets
      -fcompress-nullops -fomit-sequence numbers.  -O2 adds -fbypass-nullops.

  -D  Debug options (concatenated or separate flags like "perl -D").

  -Do Prints each OP as it's processed.

  -Db Print debugging information about bytecompiler progress.

  -Da Tells the (bytecode) assembler to include source assembler lines in its
      output as bytecode comments.

  -DC Prints each CV taken from the final symbol tree walk.

  -S  Output (bytecode) assembler source rather than piping it through the
      assembler and outputting bytecode.

  -upackage
      Stores package in the output.


EXAMPLES

      perl -MO=Bytecode,-O6,-ofoo.plc,-umain foo.pl

      perl -MO=Bytecode,-S,-umain foo.pl > foo.S
      assemble foo.S > foo.plc

  Note that "assemble" lives in the "B" subdirectory of your perl library
  directory. The utility called perlcc may also be used to help make use of
  this compiler.

      perl -MO=Bytecode,-uFoo,-oFoo.pmc Foo.pm


BUGS

  Output is still huge and there are still occasional crashes during either
  compilation or ByteLoading. Current status: experimental.


AUTHORS

  Malcolm Beattie, "mbeattie@sable.ox.ac.uk" Benjamin Stuhl,
  "sho_pi@hotmail.com"

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