The OpenNET Project / Index page

[ новости /+++ | форум | теги | ]

Интерактивная система просмотра системных руководств (man-ов)

 ТемаНаборКатегория 
 
 [Cписок руководств | Печать]

CC (3)
  • CC (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • CC (1) ( FreeBSD man: Команды и прикладные программы пользовательского уровня )
  • >> CC (3) ( Solaris man: Библиотечные вызовы )
  • 
    
    

    NAME

         B::CC - Perl compiler's optimized C translation backend
    
    
    

    SYNOPSIS

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

    DESCRIPTION

         This compiler backend takes Perl source and generates C
         source code corresponding to the flow of your program. In
         other words, this backend is somewhat a "real" compiler in
         the sense that many people think about compilers. Note
         however that, currently, it is a very poor compiler in that
         although it generates (mostly, or at least sometimes)
         correct code, it performs relatively few optimisations.
         This will change as the compiler develops. The result is
         that running an executable compiled with this backend may
         start up more quickly than running the original Perl program
         (a feature shared by the C compiler backend--see B::C) and
         may also execute slightly faster. This is by no means a good
         optimising compiler--yet.
    
    
    

    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
    
         -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
             figure 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
             packages (i.e.  of the form A::B) where package A does
             not contain any subs.
    
    
         -mModulename
             Instead of generating source for a runnable executable,
             generate source for an XSUB module. The boot_Modulename
             function (which DynaLoader can look for) does the
             appropriate initialisation and runs the main part of the
             Perl source that is being compiled.
    
         -D  Debug options (concatenated or separate flags like perl
             -D).
    
         -Dr Writes debugging output to STDERR just as it's about to
             write to the program's runtime (otherwise writes
             debugging info as comments in its C output).
    
         -DO Outputs each OP as it's compiled
    
         -Ds Outputs the contents of the shadow stack at each OP
    
         -Dp Outputs the contents of the shadow pad of lexicals as
             it's loaded for each sub or the main program.
    
         -Dq Outputs the name of each fake PP function in the queue
             as it's about to process it.
    
         -Dl Output the filename and line number of each original
             line of Perl code as it's processed (pp_nextstate).
    
         -Dt Outputs timing information of compilation stages.
    
         -f  Force optimisations on or off one at a time.
    
         -ffreetmps-each-bblock
             Delays FREETMPS from the end of each statement to the
             end of the each basic block.
    
         -ffreetmps-each-loop
             Delays FREETMPS from the end of each statement to the
             end of the group of basic blocks forming a loop. At most
             one of the freetmps-each-* options can be used.
    
         -fomit-taint
             Omits generating code for handling perl's tainting
             mechanism.
    
         -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.
             Currently, -O1 sets -ffreetmps-each-bblock and -O2 sets
             -ffreetmps-each-loop.
    
    
    

    EXAMPLES

                 perl -MO=CC,-O2,-ofoo.c foo.pl
                 perl cc_harness -o foo foo.c
    
         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=CC,-mFoo,-oFoo.c Foo.pm
                 perl cc_harness -shared -c -o Foo.so Foo.c
    
    
    
    

    BUGS

         Plenty. Current status: experimental.
    
    
    

    DIFFERENCES

         These aren't really bugs but they are constructs which are
         heavily tied to perl's compile-and-go implementation and
         with which this compiler backend cannot cope.
    
         Loops
    
         Standard perl calculates the target of "next", "last", and
         "redo" at run-time. The compiler calculates the targets at
         compile-time.  For example, the program
    
             sub skip_on_odd { next NUMBER if $_[0] % 2 }
             NUMBER: for ($i = 0; $i < 5; $i++) {
                 skip_on_odd($i);
                 print $i;
             }
    
         produces the output
    
             024
    
         with standard perl but gives a compile-time error with the
         compiler.
    
         Context of ".."
    
         The context (scalar or array) of the ".." operator
         determines whether it behaves as a range or a flip/flop.
         Standard perl delays until runtime the decision of which
         context it is in but the compiler needs to know the context
         at compile-time. For example,
    
             @a = (4,6,1,0,0,1);
             sub range { (shift @a)..(shift @a) }
             print range();
             while (@a) { print scalar(range()) }
    
         generates the output
    
             456123E0
    
         with standard Perl but gives a compile-time error with
         compiled Perl.
    
         Arithmetic
    
         Compiled Perl programs use native C arithemtic much more
         frequently than standard perl. Operations on large numbers
         or on boundary cases may produce different behaviour.
    
         Deprecated features
    
         Features of standard perl such as $[ which have been
         deprecated in standard perl since Perl5 was released have
         not been implemented in the compiler.
    
    
    

    AUTHOR

         Malcolm Beattie, [email protected]
    
    
    
    


    Поиск по тексту MAN-ов: 




    Партнёры:
    PostgresPro
    Inferno Solutions
    Hosting by Hoster.ru
    Хостинг:

    Закладки на сайте
    Проследить за страницей
    Created 1996-2024 by Maxim Chirkov
    Добавить, Поддержать, Вебмастеру