B::Bytecode - Perl compiler's bytecode backend
perl -MO=Bytecode[,OPTIONS] foo.pl
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.
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.
=back
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
Output is still huge and there are still occasional crashes during
either compilation or ByteLoading. Current status: experimental.
Malcolm Beattie, mbeattie@sable.ox.ac.uk
Benjamin Stuhl, sho_pi@hotmail.com
