Initial commit of OpenSPARC T2 architecture model.

[OpenSPARC-T2-SAM] / sam-t2 / devtools / amd64 / lib / perl5 / 5.8.8 / i86pc-solaris-64-ld / B / Bytecode.pm

# B::Bytecode.pm
# Copyright (c) 2003 Enache Adrian. All rights reserved.
# This module is free software; you can redistribute and/or modify
# it under the same terms as Perl itself.

# Based on the original Bytecode.pm module written by Malcolm Beattie.

package B::Bytecode;

our $VERSION = '1.01_01';

use strict;
use Config;
use B qw(class main_cv main_root main_start cstring comppadlist
       defstash curstash begin_av init_av end_av inc_gv warnhook diehook
       dowarn SVt_PVGV SVt_PVHV OPf_SPECIAL OPf_STACKED OPf_MOD
       OPpLVAL_INTRO SVf_FAKE SVf_READONLY);
use B::Asmdata qw(@specialsv_name);
use B::Assembler qw(asm newasm endasm);

#################################################

my ($varix, $opix, $savebegins, %walked, %files, @cloop);
my %strtab = (0,0);
my %svtab = (0,0);
my %optab = (0,0);
my %spectab = (0,0);
my $tix = 1;
sub asm;
sub nice ($) { }

BEGIN {
   my $ithreads = $Config{'useithreads'} eq 'define';
   eval qq{
       sub ITHREADS() { $ithreads }
       sub VERSION() { $] }
   }; die $@ if $@;
}

#################################################

sub pvstring {
   my $pv = shift;
   defined($pv) ? cstring ($pv."\0") : "\"\"";
}

sub pvix {
   my $str = pvstring shift;
   my $ix = $strtab{$str};
   defined($ix) ? $ix : do {
       asm "newpv", $str;
       asm "stpv", $strtab{$str} = $tix;
       $tix++;
   }
}

sub B::OP::ix {
   my $op = shift;
   my $ix = $optab{$$op};
   defined($ix) ? $ix : do {
       nice "[".$op->name." $tix]";
       asm "newopx", $op->size | $op->type <<7;
       $optab{$$op} = $opix = $ix = $tix++;
       $op->bsave($ix);
       $ix;
   }
}

sub B::SPECIAL::ix {
   my $spec = shift;
   my $ix = $spectab{$$spec};
   defined($ix) ? $ix : do {
       nice '['.$specialsv_name[$$spec].']';
       asm "ldspecsvx", $$spec;
       $spectab{$$spec} = $varix = $tix++;
   }
}

sub B::SV::ix {
   my $sv = shift;
   my $ix = $svtab{$$sv};
   defined($ix) ? $ix : do {
       nice '['.class($sv).']';
       asm "newsvx", $sv->FLAGS;
       $svtab{$$sv} = $varix = $ix = $tix++;
       $sv->bsave($ix);
       $ix;
   }
}

sub B::GV::ix {
   my ($gv,$desired) = @_;
   my $ix = $svtab{$$gv};
   defined($ix) ? $ix : do {
       if ($gv->GP) {
           my ($svix, $avix, $hvix, $cvix, $ioix, $formix);
           nice "[GV]";
           my $name = $gv->STASH->NAME . "::" . $gv->NAME;
           asm "gv_fetchpvx", cstring $name;
           $svtab{$$gv} = $varix = $ix = $tix++;
           asm "sv_flags", $gv->FLAGS;
           asm "sv_refcnt", $gv->REFCNT;
           asm "xgv_flags", $gv->GvFLAGS;

           asm "gp_refcnt", $gv->GvREFCNT;
           asm "load_glob", $ix if $name eq "CORE::GLOBAL::glob";
           return $ix
                   unless $desired || desired $gv;
           $svix = $gv->SV->ix;
           $avix = $gv->AV->ix;
           $hvix = $gv->HV->ix;

   # XXX {{{{
           my $cv = $gv->CV;
           $cvix = $$cv && defined $files{$cv->FILE} ? $cv->ix : 0;
           my $form = $gv->FORM;
           $formix = $$form && defined $files{$form->FILE} ? $form->ix : 0;

           $ioix = $name !~ /STDOUT$/ ? $gv->IO->ix : 0;       
                                                           # }}}} XXX

           nice "-GV-",
           asm "ldsv", $varix = $ix unless $ix == $varix;
           asm "gp_sv", $svix;
           asm "gp_av", $avix;
           asm "gp_hv", $hvix;
           asm "gp_cv", $cvix;
           asm "gp_io", $ioix;
           asm "gp_cvgen", $gv->CVGEN;
           asm "gp_form", $formix;
           asm "gp_file", pvix $gv->FILE;
           asm "gp_line", $gv->LINE;
           asm "formfeed", $svix if $name eq "main::\cL";
       } else {
           nice "[GV]";
           asm "newsvx", $gv->FLAGS;
           $svtab{$$gv} = $varix = $ix = $tix++;
           my $stashix = $gv->STASH->ix;
           $gv->B::PVMG::bsave($ix);
           asm "xgv_flags", $gv->GvFLAGS;
           asm "xgv_stash", $stashix;
       }
       $ix;
   }
}

sub B::HV::ix {
   my $hv = shift;
   my $ix = $svtab{$$hv};
   defined($ix) ? $ix : do {
       my ($ix,$i,@array);
       my $name = $hv->NAME;
       if ($name) {
           nice "[STASH]";
           asm "gv_stashpvx", cstring $name;
           asm "sv_flags", $hv->FLAGS;
           $svtab{$$hv} = $varix = $ix = $tix++;
           asm "xhv_name", pvix $name;
           # my $pmrootix = $hv->PMROOT->ix;   # XXX
           asm "ldsv", $varix = $ix unless $ix == $varix;
           # asm "xhv_pmroot", $pmrootix;      # XXX
       } else {
           nice "[HV]";
           asm "newsvx", $hv->FLAGS;
           $svtab{$$hv} = $varix = $ix = $tix++;
           my $stashix = $hv->SvSTASH->ix;
           for (@array = $hv->ARRAY) {
               next if $i = not $i;
               $_ = $_->ix;
           }
           nice "-HV-",
           asm "ldsv", $varix = $ix unless $ix == $varix;
           ($i = not $i) ? asm ("newpv", pvstring $_) : asm("hv_store", $_)
               for @array;
           if (VERSION < 5.009) {
               asm "xnv", $hv->NVX;
           }
           asm "xmg_stash", $stashix;
           asm "xhv_riter", $hv->RITER;
       }
       asm "sv_refcnt", $hv->REFCNT;
       $ix;
   }
}

sub B::NULL::ix {
   my $sv = shift;
   $$sv ? $sv->B::SV::ix : 0;
}

sub B::NULL::opwalk { 0 }

#################################################

sub B::NULL::bsave {
   my ($sv,$ix) = @_;

   nice '-'.class($sv).'-',
   asm "ldsv", $varix = $ix unless $ix == $varix;
   asm "sv_refcnt", $sv->REFCNT;
}

sub B::SV::bsave;
   *B::SV::bsave = *B::NULL::bsave;

sub B::RV::bsave {
   my ($sv,$ix) = @_;
   my $rvix = $sv->RV->ix;
   $sv->B::NULL::bsave($ix);
   asm "xrv", $rvix;
}

sub B::PV::bsave {
   my ($sv,$ix) = @_;
   $sv->B::NULL::bsave($ix);
   asm "newpv", pvstring $sv->PVBM;
   asm "xpv";
}

sub B::IV::bsave {
   my ($sv,$ix) = @_;
   $sv->B::NULL::bsave($ix);
   asm "xiv", $sv->IVX;
}

sub B::NV::bsave {
   my ($sv,$ix) = @_;
   $sv->B::NULL::bsave($ix);
   asm "xnv", sprintf "%.40g", $sv->NVX;
}

sub B::PVIV::bsave {
   my ($sv,$ix) = @_;
   $sv->POK ?
       $sv->B::PV::bsave($ix):
   $sv->ROK ?
       $sv->B::RV::bsave($ix):
       $sv->B::NULL::bsave($ix);
   if (VERSION >= 5.009) {
       # See note below in B::PVNV::bsave
       return if $sv->isa('B::AV');
       return if $sv->isa('B::HV');
   }
   asm "xiv", !ITHREADS && $sv->FLAGS & (SVf_FAKE|SVf_READONLY) ?
       "0 but true" : $sv->IVX;
}

sub B::PVNV::bsave {
   my ($sv,$ix) = @_;
   $sv->B::PVIV::bsave($ix);
   if (VERSION >= 5.009) {
       # Magical AVs end up here, but AVs now don't have an NV slot actually
       # allocated. Hence don't write out assembly to store the NV slot if
       # we're actually an array.
       return if $sv->isa('B::AV');
       # Likewise HVs have no NV slot actually allocated.
       # I don't think that they can get here, but better safe than sorry
       return if $sv->isa('B::HV');
   }
   asm "xnv", sprintf "%.40g", $sv->NVX;
}

sub B::PVMG::domagic {
   my ($sv,$ix) = @_;
   nice '-MAGICAL-';
   my @mglist = $sv->MAGIC;
   my (@mgix, @namix);
   for (@mglist) {
       push @mgix, $_->OBJ->ix;
       push @namix, $_->PTR->ix if $_->LENGTH == B::HEf_SVKEY;
   }

   nice '-'.class($sv).'-',
   asm "ldsv", $varix = $ix unless $ix == $varix;
   for (@mglist) {
       asm "sv_magic", cstring $_->TYPE;
       asm "mg_obj", shift @mgix;
       my $length = $_->LENGTH;
       if ($length == B::HEf_SVKEY) {
           asm "mg_namex", shift @namix;
       } elsif ($length) {
           asm "newpv", pvstring $_->PTR;
           asm "mg_name";
       }
   }
}

sub B::PVMG::bsave {
   my ($sv,$ix) = @_;
   my $stashix = $sv->SvSTASH->ix;
   $sv->B::PVNV::bsave($ix);
   asm "xmg_stash", $stashix;
   $sv->domagic($ix) if $sv->MAGICAL;
}

sub B::PVLV::bsave {
   my ($sv,$ix) = @_;
   my $targix = $sv->TARG->ix;
   $sv->B::PVMG::bsave($ix);
   asm "xlv_targ", $targix;
   asm "xlv_targoff", $sv->TARGOFF;
   asm "xlv_targlen", $sv->TARGLEN;
   asm "xlv_type", $sv->TYPE;

}

sub B::BM::bsave {
   my ($sv,$ix) = @_;
   $sv->B::PVMG::bsave($ix);
   asm "xpv_cur", $sv->CUR;
   asm "xbm_useful", $sv->USEFUL;
   asm "xbm_previous", $sv->PREVIOUS;
   asm "xbm_rare", $sv->RARE;
}

sub B::IO::bsave {
   my ($io,$ix) = @_;
   my $topix = $io->TOP_GV->ix;
   my $fmtix = $io->FMT_GV->ix;
   my $bottomix = $io->BOTTOM_GV->ix;
   $io->B::PVMG::bsave($ix);
   asm "xio_lines", $io->LINES;
   asm "xio_page", $io->PAGE;
   asm "xio_page_len", $io->PAGE_LEN;
   asm "xio_lines_left", $io->LINES_LEFT;
   asm "xio_top_name", pvix $io->TOP_NAME;
   asm "xio_top_gv", $topix;
   asm "xio_fmt_name", pvix $io->FMT_NAME;
   asm "xio_fmt_gv", $fmtix;
   asm "xio_bottom_name", pvix $io->BOTTOM_NAME;
   asm "xio_bottom_gv", $bottomix;
   asm "xio_subprocess", $io->SUBPROCESS;
   asm "xio_type", ord $io->IoTYPE;
   # asm "xio_flags", ord($io->IoFLAGS) & ~32;         # XXX XXX
}

sub B::CV::bsave {
   my ($cv,$ix) = @_;
   my $stashix = $cv->STASH->ix;
   my $gvix = $cv->GV->ix;
   my $padlistix = $cv->PADLIST->ix;
   my $outsideix = $cv->OUTSIDE->ix;
   my $constix = $cv->CONST ? $cv->XSUBANY->ix : 0;
   my $startix = $cv->START->opwalk;
   my $rootix = $cv->ROOT->ix;

   $cv->B::PVMG::bsave($ix);
   asm "xcv_stash", $stashix;
   asm "xcv_start", $startix;
   asm "xcv_root", $rootix;
   asm "xcv_xsubany", $constix;
   asm "xcv_gv", $gvix;
   asm "xcv_file", pvix $cv->FILE if $cv->FILE;        # XXX AD
   asm "xcv_padlist", $padlistix;
   asm "xcv_outside", $outsideix;
   asm "xcv_flags", $cv->CvFLAGS;
   asm "xcv_outside_seq", $cv->OUTSIDE_SEQ;
   asm "xcv_depth", $cv->DEPTH;
}

sub B::FM::bsave {
   my ($form,$ix) = @_;

   $form->B::CV::bsave($ix);
   asm "xfm_lines", $form->LINES;
}

sub B::AV::bsave {
   my ($av,$ix) = @_;
   return $av->B::PVMG::bsave($ix) if $av->MAGICAL;
   my @array = $av->ARRAY;
   $_ = $_->ix for @array;
   my $stashix = $av->SvSTASH->ix;

   nice "-AV-",
   asm "ldsv", $varix = $ix unless $ix == $varix;
   asm "av_extend", $av->MAX if $av->MAX >= 0;
   asm "av_pushx", $_ for @array;
   asm "sv_refcnt", $av->REFCNT;
   if (VERSION < 5.009) {
       asm "xav_flags", $av->AvFLAGS;
   }
   asm "xmg_stash", $stashix;
}

sub B::GV::desired {
   my $gv = shift;
   my ($cv, $form);
   $files{$gv->FILE} && $gv->LINE
   || ${$cv = $gv->CV} && $files{$cv->FILE}
   || ${$form = $gv->FORM} && $files{$form->FILE}
}

sub B::HV::bwalk {
   my $hv = shift;
   return if $walked{$$hv}++;
   my %stash = $hv->ARRAY;
   while (my($k,$v) = each %stash) {
       if ($v->SvTYPE == SVt_PVGV) {
           my $hash = $v->HV;
           if ($$hash && $hash->NAME) {
               $hash->bwalk;
           } 
           $v->ix(1) if desired $v;
       } else {
           nice "[prototype]";
           asm "gv_fetchpvx", cstring $hv->NAME . "::$k";
           $svtab{$$v} = $varix = $tix;
           $v->bsave($tix++);
           asm "sv_flags", $v->FLAGS;
       }
   }
}

######################################################


sub B::OP::bsave_thin {
   my ($op, $ix) = @_;
   my $next = $op->next;
   my $nextix = $optab{$$next};
   $nextix = 0, push @cloop, $op unless defined $nextix;
   if ($ix != $opix) {
       nice '-'.$op->name.'-',
       asm "ldop", $opix = $ix;
   }
   asm "op_next", $nextix;
   asm "op_targ", $op->targ if $op->type;              # tricky
   asm "op_flags", $op->flags;
   asm "op_private", $op->private;
}

sub B::OP::bsave;
   *B::OP::bsave = *B::OP::bsave_thin;

sub B::UNOP::bsave {
   my ($op, $ix) = @_;
   my $name = $op->name;
   my $flags = $op->flags;
   my $first = $op->first;
   my $firstix = 
       $name =~ /fl[io]p/
                       # that's just neat
   ||  (!ITHREADS && $name eq 'regcomp')
                       # trick for /$a/o in pp_regcomp
   ||  $name eq 'rv2sv'
           && $op->flags & OPf_MOD     
           && $op->private & OPpLVAL_INTRO
                       # change #18774 made my life hard
   ?   $first->ix
   :   0;

   $op->B::OP::bsave($ix);
   asm "op_first", $firstix;
}

sub B::BINOP::bsave {
   my ($op, $ix) = @_;
   if ($op->name eq 'aassign' && $op->private & B::OPpASSIGN_HASH()) {
       my $last = $op->last;
       my $lastix = do {
           local *B::OP::bsave = *B::OP::bsave_fat;
           local *B::UNOP::bsave = *B::UNOP::bsave_fat;
           $last->ix;
       };
       asm "ldop", $lastix unless $lastix == $opix;
       asm "op_targ", $last->targ;
       $op->B::OP::bsave($ix);
       asm "op_last", $lastix;
   } else {
       $op->B::OP::bsave($ix);
   }
}

# not needed if no pseudohashes

*B::BINOP::bsave = *B::OP::bsave if VERSION >= 5.009;

# deal with sort / formline 

sub B::LISTOP::bsave {
   my ($op, $ix) = @_;
   my $name = $op->name;
   sub blocksort() { OPf_SPECIAL|OPf_STACKED }
   if ($name eq 'sort' && ($op->flags & blocksort) == blocksort) {
       my $first = $op->first;
       my $pushmark = $first->sibling;
       my $rvgv = $pushmark->first;
       my $leave = $rvgv->first;

       my $leaveix = $leave->ix;

       my $rvgvix = $rvgv->ix;
       asm "ldop", $rvgvix unless $rvgvix == $opix;
       asm "op_first", $leaveix;

       my $pushmarkix = $pushmark->ix;
       asm "ldop", $pushmarkix unless $pushmarkix == $opix;
       asm "op_first", $rvgvix;

       my $firstix = $first->ix;
       asm "ldop", $firstix unless $firstix == $opix;
       asm "op_sibling", $pushmarkix;

       $op->B::OP::bsave($ix);
       asm "op_first", $firstix;
   } elsif ($name eq 'formline') {
       $op->B::UNOP::bsave_fat($ix);
   } else {
       $op->B::OP::bsave($ix);
   }
}

# fat versions

sub B::OP::bsave_fat {
   my ($op, $ix) = @_;
   my $siblix = $op->sibling->ix;

   $op->B::OP::bsave_thin($ix);
   asm "op_sibling", $siblix;
   # asm "op_seq", -1;                 XXX don't allocate OPs piece by piece
}

sub B::UNOP::bsave_fat {
   my ($op,$ix) = @_;
   my $firstix = $op->first->ix;

   $op->B::OP::bsave($ix);
   asm "op_first", $firstix;
}

sub B::BINOP::bsave_fat {
   my ($op,$ix) = @_;
   my $last = $op->last;
   my $lastix = $op->last->ix;
   if (VERSION < 5.009 && $op->name eq 'aassign' && $last->name eq 'null') {
       asm "ldop", $lastix unless $lastix == $opix;
       asm "op_targ", $last->targ;
   }

   $op->B::UNOP::bsave($ix);
   asm "op_last", $lastix;
}

sub B::LOGOP::bsave {
   my ($op,$ix) = @_;
   my $otherix = $op->other->ix;

   $op->B::UNOP::bsave($ix);
   asm "op_other", $otherix;
}

sub B::PMOP::bsave {
   my ($op,$ix) = @_;
   my ($rrop, $rrarg, $rstart);

   # my $pmnextix = $op->pmnext->ix;   # XXX

   if (ITHREADS) {
       if ($op->name eq 'subst') {
           $rrop = "op_pmreplroot";
           $rrarg = $op->pmreplroot->ix;
           $rstart = $op->pmreplstart->ix;
       } elsif ($op->name eq 'pushre') {
           $rrop = "op_pmreplrootpo";
           $rrarg = $op->pmreplroot;
       }
       $op->B::BINOP::bsave($ix);
       asm "op_pmstashpv", pvix $op->pmstashpv;
   } else {
       $rrop = "op_pmreplrootgv";
       $rrarg = $op->pmreplroot->ix;
       $rstart = $op->pmreplstart->ix if $op->name eq 'subst';
       my $stashix = $op->pmstash->ix;
       $op->B::BINOP::bsave($ix);
       asm "op_pmstash", $stashix;
   }

   asm $rrop, $rrarg if $rrop;
   asm "op_pmreplstart", $rstart if $rstart;

   asm "op_pmflags", $op->pmflags;
   asm "op_pmpermflags", $op->pmpermflags;
   asm "op_pmdynflags", $op->pmdynflags;
   # asm "op_pmnext", $pmnextix;       # XXX
   asm "newpv", pvstring $op->precomp;
   asm "pregcomp";
}

sub B::SVOP::bsave {
   my ($op,$ix) = @_;
   my $svix = $op->sv->ix;

   $op->B::OP::bsave($ix);
   asm "op_sv", $svix;
}

sub B::PADOP::bsave {
   my ($op,$ix) = @_;

   $op->B::OP::bsave($ix);
   asm "op_padix", $op->padix;
}

sub B::PVOP::bsave {
   my ($op,$ix) = @_;
   $op->B::OP::bsave($ix);
   return unless my $pv = $op->pv;

   if ($op->name eq 'trans') {
       asm "op_pv_tr", join ',', length($pv)/2, unpack("s*", $pv);
   } else {
       asm "newpv", pvstring $pv;
       asm "op_pv";
   }
}

sub B::LOOP::bsave {
   my ($op,$ix) = @_;
   my $nextix = $op->nextop->ix;
   my $lastix = $op->lastop->ix;
   my $redoix = $op->redoop->ix;

   $op->B::BINOP::bsave($ix);
   asm "op_redoop", $redoix;
   asm "op_nextop", $nextix;
   asm "op_lastop", $lastix;
}

sub B::COP::bsave {
   my ($cop,$ix) = @_;
   my $warnix = $cop->warnings->ix;
   my $ioix = $cop->io->ix;
   if (ITHREADS) {
       $cop->B::OP::bsave($ix);
       asm "cop_stashpv", pvix $cop->stashpv;
       asm "cop_file", pvix $cop->file;
   } else {
       my $stashix = $cop->stash->ix;
       my $fileix = $cop->filegv->ix(1);
       $cop->B::OP::bsave($ix);
       asm "cop_stash", $stashix;
       asm "cop_filegv", $fileix;
   }
   asm "cop_label", pvix $cop->label if $cop->label;   # XXX AD
   asm "cop_seq", $cop->cop_seq;
   asm "cop_arybase", $cop->arybase;
   asm "cop_line", $cop->line;
   asm "cop_warnings", $warnix;
   asm "cop_io", $ioix;
}

sub B::OP::opwalk {
   my $op = shift;
   my $ix = $optab{$$op};
   defined($ix) ? $ix : do {
       my $ix;
       my @oplist = $op->oplist;
       push @cloop, undef;
       $ix = $_->ix while $_ = pop @oplist;
       while ($_ = pop @cloop) {
           asm "ldop", $optab{$$_};
           asm "op_next", $optab{${$_->next}};
       }
       $ix;
   }
}

#################################################

sub save_cq {
   my $av;
   if (($av=begin_av)->isa("B::AV")) {
       if ($savebegins) {
           for ($av->ARRAY) {
               next unless $_->FILE eq $0;
               asm "push_begin", $_->ix;
           }
       } else {
           for ($av->ARRAY) {
               next unless $_->FILE eq $0;
               # XXX BEGIN { goto A while 1; A: }
               for (my $op = $_->START; $$op; $op = $op->next) {
                   next unless $op->name eq 'require' || 
                       # this kludge needed for tests
                       $op->name eq 'gv' && do {
                           my $gv = class($op) eq 'SVOP' ?
                               $op->gv :
                               (($_->PADLIST->ARRAY)[1]->ARRAY)[$op->padix];
                           $$gv && $gv->NAME =~ /use_ok|plan/
                       };
                   asm "push_begin", $_->ix;
                   last;
               }
           }
       }
   }
   if (($av=init_av)->isa("B::AV")) {
       for ($av->ARRAY) {
           next unless $_->FILE eq $0;
           asm "push_init", $_->ix;
       }
   }
   if (($av=end_av)->isa("B::AV")) {
       for ($av->ARRAY) {
           next unless $_->FILE eq $0;
           asm "push_end", $_->ix;
       }
   }
}

sub compile {
   my ($head, $scan, $T_inhinc, $keep_syn);
   my $cwd = '';
   $files{$0} = 1;
   sub keep_syn {
       $keep_syn = 1;
       *B::OP::bsave = *B::OP::bsave_fat;
       *B::UNOP::bsave = *B::UNOP::bsave_fat;
       *B::BINOP::bsave = *B::BINOP::bsave_fat;
       *B::LISTOP::bsave = *B::LISTOP::bsave_fat;
   }
   sub bwarn { print STDERR "Bytecode.pm: @_\n" }

   for (@_) {
       if (/^-S/) {
           *newasm = *endasm = sub { };
           *asm = sub { print "    @_\n" };
           *nice = sub ($) { print "\n@_\n" };
       } elsif (/^-H/) {
           require ByteLoader;
           $head = "#! $^X\nuse ByteLoader $ByteLoader::VERSION;\n";
       } elsif (/^-k/) {
           keep_syn;
       } elsif (/^-o(.*)$/) {
           open STDOUT, ">$1" or die "open $1: $!";
       } elsif (/^-f(.*)$/) {
           $files{$1} = 1;
       } elsif (/^-s(.*)$/) {
           $scan = length($1) ? $1 : $0;
       } elsif (/^-b/) {
           $savebegins = 1;
   # this is here for the testsuite
       } elsif (/^-TI/) {
           $T_inhinc = 1;
       } elsif (/^-TF(.*)/) {
           my $thatfile = $1;
           *B::COP::file = sub { $thatfile };
       } else {
           bwarn "Ignoring '$_' option";
       }
   }
   if ($scan) {
       my $f;
       if (open $f, $scan) {
           while (<$f>) {
               /^#\s*line\s+\d+\s+("?)(.*)\1/ and $files{$2} = 1;
               /^#/ and next;
               if (/\bgoto\b\s*[^&]/ && !$keep_syn) {
                   bwarn "keeping the syntax tree: \"goto\" op found";
                   keep_syn;
               }
           }
       } else {
           bwarn "cannot rescan '$scan'";
       }
       close $f;
   }
   binmode STDOUT;
   return sub {
       print $head if $head;
       newasm sub { print @_ };

       defstash->bwalk;
       asm "main_start", main_start->opwalk;
       asm "main_root", main_root->ix;
       asm "main_cv", main_cv->ix;
       asm "curpad", (comppadlist->ARRAY)[1]->ix;

       asm "signal", cstring "__WARN__"                # XXX
           if warnhook->ix;
       asm "incav", inc_gv->AV->ix if $T_inhinc;
       save_cq;
       asm "incav", inc_gv->AV->ix if $T_inhinc;
       asm "dowarn", dowarn;

       {
           no strict 'refs';
           nice "<DATA>";
           my $dh = *{defstash->NAME."::DATA"};
           unless (eof $dh) {
               local undef $/;
               asm "data", ord 'D';
               print <$dh>;
           } else {
               asm "ret";
           }
       }

       endasm;
   }
}

1;

=head1 NAME

B::Bytecode - Perl compiler's bytecode backend

=head1 SYNOPSIS

B<perl -MO=Bytecode>[B<,-H>][B<,-o>I<script.plc>] I<script.pl>

=head1 DESCRIPTION

Compiles a Perl script into a bytecode format that could be loaded
later by the ByteLoader module and executed as a regular Perl script.

=head1 EXAMPLE

   $ perl -MO=Bytecode,-H,-ohi -e 'print "hi!\n"'
   $ perl hi
   hi!

=head1 OPTIONS

=over 4

=item B<-b>

Save all the BEGIN blocks. Normally only BEGIN blocks that C<require>
other files (ex. C<use Foo;>) are saved.

=item B<-H>

prepend a C<use ByteLoader VERSION;> line to the produced bytecode.

=item B<-k>

keep the syntax tree - it is stripped by default.

=item B<-o>I<outfile>

put the bytecode in <outfile> instead of dumping it to STDOUT.

=item B<-s>

scan the script for C<# line ..> directives and for <goto LABEL>
expressions. When gotos are found keep the syntax tree.

=back

=head1 KNOWN BUGS

=over 4

=item *

C<BEGIN { goto A: while 1; A: }> won't even compile.

=item *

C<?...?> and C<reset> do not work as expected.

=item *

variables in C<(?{ ... })> constructs are not properly scoped.

=item *

scripts that use source filters will fail miserably. 

=back

=head1 NOTICE

There are also undocumented bugs and options.

THIS CODE IS HIGHLY EXPERIMENTAL. USE AT YOUR OWN RISK.

=head1 AUTHORS

Originally written by Malcolm Beattie <mbeattie@sable.ox.ac.uk> and
modified by Benjamin Stuhl <sho_pi@hotmail.com>.

Rewritten by Enache Adrian <enache@rdslink.ro>, 2003 a.d.

=cut