ext::B::B::C(3p)Perl Programmers Reference Guide ext::B::B::C(3p)
B::C - Perl compiler's C backend
perl -MO=C[,OPTIONS] foo.pl
This compiler backend takes Perl source and generates C
source code corresponding to the internal structures that
perl uses to run your program. When the generated C source
is compiled and run, it cuts out 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 be
either a help or a hindrance.
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
-v Verbose compilation (currently gives a few compilation
statistics).
-- Force end of options
-uPackname
Force apparently unused subs from package Packname to be
compiled. This allows programs to use eval "foo()" even
when sub foo is never seen to be used at compile time.
The down side is that any subs which really are never
used also have code generated. This option is necessary,
for example, if you have a signal handler foo which you
initialise with "$SIG{BAR} = "foo"". A better fix,
though, is just to change it to "$SIG{BAR} = \&foo". You
can have multiple -u options. The compiler tries to fig-
ure out which packages may possibly have subs in which
need compiling but the current version doesn't do it
very well. In particular, it is confused by nested pack-
ages (i.e. of the form "A::B") where package "A" does
not contain any subs.
-D Debug options (concatenated or separate flags like "perl
-D").
-Do OPs, prints each OP as it's processed
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-Dc COPs, prints COPs as processed (incl. file & line num)
-DA prints AV information on saving
-DC prints CV information on saving
-DM prints MAGIC information on saving
-f Force options/optimisations on or off one at a time. You
can explicitly disable an option using -fno-option. All
options default to disabled.
-fcog
Copy-on-grow: PVs declared and initialised stati-
cally.
-fsave-data
Save package::DATA filehandles ( only available with
PerlIO ).
-fppaddr
Optimize the initialization of op_ppaddr.
-fwarn-sv
Optimize the initialization of cop_warnings.
-fuse-script-name
Use the script name instead of the program name as
$0.
-fsave-sig-hash
Save compile-time modifications to the %SIG hash.
-On Optimisation level (n = 0, 1, 2, ...). -O means -O1.
-O0 Disable all optimizations.
-O1 Enable -fcog.
-O2 Enable -fppaddr, -fwarn-sv.
-llimit
Some C compilers impose an arbitrary limit on the length
of string constants (e.g. 2048 characters for Microsoft
Visual C++). The -llimit options tells the C backend
not to generate string literals exceeding that limit.
perl -MO=C,-ofoo.c foo.pl
perl cc_harness -o foo foo.c
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Note that "cc_harness" 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=C,-v,-DcA,-l2048 bar.pl > /dev/null
Plenty. Current status: experimental.
Malcolm Beattie, "mbeattie@sable.ox.ac.uk"
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