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package B::Clobbers;
our $VERSION = '0.01';
use strict;
use B::Walker qw(padval walk);
use B qw(ppname OPpLVAL_INTRO);
our @vars = qw(_ / , \ ");
our %vars = map { $_ => 1 } @vars;
our $Verbose = 0;
sub do_gvsv ($) {
my $op = shift;
my $var = padval($op->padix)->SAFENAME;
return unless $vars{$var};
if ($op->private & OPpLVAL_INTRO) {
$B::Walker::BlockData{$var} = 1;
print STDERR "local \$$var at $0 line $B::Walker::Line\n" if $Verbose;
}
elsif ($op = $op->next and $$op and $op->name eq "sassign") {
return if $B::Walker::BlockData{$var};
print "\t*** \$$var clobbered at $0 line $B::Walker::Line\n";
}
}
sub do_rv2gv ($) {
my $op = shift;
my $gv = $op->first;
return unless $gv->name eq "gv";
my $var = padval($gv->padix)->SAFENAME;
return unless $vars{$var};
if ($op->private & OPpLVAL_INTRO) {
$B::Walker::BlockData{$var} = 1;
print STDERR "local \*$var at $0 line $B::Walker::Line\n" if $Verbose;
}
elsif ($op = $op->next and $$op and $op->name eq "sassign") {
return if $B::Walker::BlockData{$var};
print "\t*** \*$var clobbered at $0 line $B::Walker::Line\n";
}
}
sub do_readline ($) {
my $op = shift;
$op = $op->next;
$op = $op->first while ref($op) eq "B::UNOP";
return unless $op->name eq "gvsv";
my $var = padval($op->padix)->SAFENAME;
return unless $vars{$var};
return if $B::Walker::BlockData{$var};
print "\t*** \$$var clobbered at $0 line $B::Walker::Line\n";
}
sub do_enteriter ($) {
my $op = shift;
my $op = $op->first->sibling->sibling;
return unless $$op;
$op = $op->first if $op->name eq "rv2gv";
return unless $op->name eq "gv";
my $gv = ref($op) eq "B::PADOP" ? padval($op->padix) : $op->gv;
my $var = $gv->SAFENAME;
return unless $vars{$var};
print STDERR "implicitly localized \$$var at $0 line $B::Walker::Line\n" if $Verbose;
$B::Walker::BlockData{_} = 1;
}
%B::Walker::Ops = (
gvsv => \&do_gvsv,
rv2gv => \&do_rv2gv,
readline => \&do_readline,
enteriter => \&do_enteriter,
grepwhile => sub { $B::Walker::BlockData{_} = 1 },
mapwhile => sub { $B::Walker::BlockData{_} = 1 },
);
sub compile {
my $pkg = __PACKAGE__;
for my $opt (@_) {
$opt =~ /^-(?:v|-?verbose)$/ and ++$Verbose or
die "$pkg: unknown option: $opt\n";
}
return sub {
local $| = 1;
local $SIG{__DIE__} = sub {
print STDERR "Dying at $0 line $B::Walker::Line\n";
require Carp;
Carp::cluck();
};
walk();
}
}
1;
__END__
=head1 NAME
B::Clobbers - clobbering analyzer
=head1 COPYING
Copyright (c) 2007 Alexey Tourbin, ALT Linux Team.
This is free software; you can redistribute it and/or modify it under the terms
of the GNU General Public License as published by the Free Software Foundation;
either version 2 of the License, or (at your option) any later version.
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