393 lines
9.7 KiB
Perl
393 lines
9.7 KiB
Perl
package B::Xref;
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=head1 NAME
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B::Xref - Generates cross reference reports for Perl programs
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=head1 SYNOPSIS
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perl -MO=Xref[,OPTIONS] foo.pl
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=head1 DESCRIPTION
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The B::Xref module is used to generate a cross reference listing of all
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definitions and uses of variables, subroutines and formats in a Perl program.
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It is implemented as a backend for the Perl compiler.
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The report generated is in the following format:
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File filename1
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Subroutine subname1
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Package package1
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object1 C<line numbers>
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object2 C<line numbers>
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...
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Package package2
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...
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Each B<File> section reports on a single file. Each B<Subroutine> section
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reports on a single subroutine apart from the special cases
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"(definitions)" and "(main)". These report, respectively, on subroutine
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definitions found by the initial symbol table walk and on the main part of
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the program or module external to all subroutines.
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The report is then grouped by the B<Package> of each variable,
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subroutine or format with the special case "(lexicals)" meaning
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lexical variables. Each B<object> name (implicitly qualified by its
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containing B<Package>) includes its type character(s) at the beginning
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where possible. Lexical variables are easier to track and even
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included dereferencing information where possible.
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The C<line numbers> are a comma separated list of line numbers (some
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preceded by code letters) where that object is used in some way.
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Simple uses aren't preceded by a code letter. Introductions (such as
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where a lexical is first defined with C<my>) are indicated with the
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letter "i". Subroutine and method calls are indicated by the character
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"&". Subroutine definitions are indicated by "s" and format
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definitions by "f".
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=head1 OPTIONS
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Option words are separated by commas (not whitespace) and follow the
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usual conventions of compiler backend options.
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=over 8
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=item C<-oFILENAME>
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Directs output to C<FILENAME> instead of standard output.
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=item C<-r>
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Raw output. Instead of producing a human-readable report, outputs a line
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in machine-readable form for each definition/use of a variable/sub/format.
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=item C<-D[tO]>
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(Internal) debug options, probably only useful if C<-r> included.
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The C<t> option prints the object on the top of the stack as it's
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being tracked. The C<O> option prints each operator as it's being
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processed in the execution order of the program.
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=back
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=head1 BUGS
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Non-lexical variables are quite difficult to track through a program.
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Sometimes the type of a non-lexical variable's use is impossible to
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determine. Introductions of non-lexical non-scalars don't seem to be
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reported properly.
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=head1 AUTHOR
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Malcolm Beattie, mbeattie@sable.ox.ac.uk.
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=cut
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use strict;
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use B qw(peekop class comppadlist main_start svref_2object walksymtable);
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# Constants (should probably be elsewhere)
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sub OPpLVAL_INTRO () { 128 }
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sub SVf_POK () { 0x40000 }
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sub UNKNOWN { ["?", "?", "?"] }
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my @pad; # lexicals in current pad
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# as ["(lexical)", type, name]
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my %done; # keyed by $$op: set when each $op is done
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my $top = UNKNOWN; # shadows top element of stack as
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# [pack, type, name] (pack can be "(lexical)")
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my $file; # shadows current filename
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my $line; # shadows current line number
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my $subname; # shadows current sub name
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my %table; # Multi-level hash to record all uses etc.
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my @todo = (); # List of CVs that need processing
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my %code = (intro => "i", used => "",
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subdef => "s", subused => "&",
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formdef => "f", meth => "->");
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# Options
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my ($debug_op, $debug_top, $nodefs, $raw);
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sub process {
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my ($var, $event) = @_;
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my ($pack, $type, $name) = @$var;
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if ($type eq "*") {
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if ($event eq "used") {
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return;
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} elsif ($event eq "subused") {
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$type = "&";
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}
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}
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$type =~ s/(.)\*$/$1/g;
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if ($raw) {
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printf "%-16s %-12s %5d %-12s %4s %-16s %s\n",
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$file, $subname, $line, $pack, $type, $name, $event;
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} else {
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# Wheee
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push(@{$table{$file}->{$subname}->{$pack}->{$type.$name}->{$event}},
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$line);
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}
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}
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sub load_pad {
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my $padlist = shift;
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my ($namelistav, @namelist, $ix);
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@pad = ();
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return if class($padlist) eq "SPECIAL";
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($namelistav) = $padlist->ARRAY;
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@namelist = $namelistav->ARRAY;
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for ($ix = 1; $ix < @namelist; $ix++) {
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my $namesv = $namelist[$ix];
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next if class($namesv) eq "SPECIAL";
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my ($type, $name) = $namesv->PV =~ /^(.)(.*)$/;
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$pad[$ix] = ["(lexical)", $type, $name];
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}
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}
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sub xref {
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my $start = shift;
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my $op;
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for ($op = $start; $$op; $op = $op->next) {
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last if $done{$$op}++;
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warn sprintf("top = [%s, %s, %s]\n", @$top) if $debug_top;
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warn peekop($op), "\n" if $debug_op;
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my $ppname = $op->ppaddr;
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if ($ppname =~ /^pp_(or|and|mapwhile|grepwhile)$/) {
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xref($op->other);
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} elsif ($ppname eq "pp_match" || $ppname eq "pp_subst") {
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xref($op->pmreplstart);
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} elsif ($ppname eq "pp_substcont") {
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xref($op->other->pmreplstart);
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$op = $op->other;
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redo;
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} elsif ($ppname eq "pp_cond_expr") {
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# pp_cond_expr never returns op_next
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xref($op->true);
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$op = $op->false;
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redo;
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} elsif ($ppname eq "pp_enterloop") {
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xref($op->redoop);
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xref($op->nextop);
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xref($op->lastop);
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} elsif ($ppname eq "pp_subst") {
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xref($op->pmreplstart);
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} else {
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no strict 'refs';
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&$ppname($op) if defined(&$ppname);
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}
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}
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}
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sub xref_cv {
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my $cv = shift;
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my $pack = $cv->GV->STASH->NAME;
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$subname = ($pack eq "main" ? "" : "$pack\::") . $cv->GV->NAME;
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load_pad($cv->PADLIST);
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xref($cv->START);
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$subname = "(main)";
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}
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sub xref_object {
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my $cvref = shift;
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xref_cv(svref_2object($cvref));
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}
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sub xref_main {
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$subname = "(main)";
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load_pad(comppadlist);
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xref(main_start);
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while (@todo) {
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xref_cv(shift @todo);
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}
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}
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sub pp_nextstate {
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my $op = shift;
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$file = $op->filegv->SV->PV;
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$line = $op->line;
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$top = UNKNOWN;
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}
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sub pp_padsv {
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my $op = shift;
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$top = $pad[$op->targ];
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process($top, $op->private & OPpLVAL_INTRO ? "intro" : "used");
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}
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sub pp_padav { pp_padsv(@_) }
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sub pp_padhv { pp_padsv(@_) }
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sub deref {
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my ($var, $as) = @_;
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$var->[1] = $as . $var->[1];
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process($var, "used");
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}
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sub pp_rv2cv { deref($top, "&"); }
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sub pp_rv2hv { deref($top, "%"); }
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sub pp_rv2sv { deref($top, "\$"); }
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sub pp_rv2av { deref($top, "\@"); }
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sub pp_rv2gv { deref($top, "*"); }
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sub pp_gvsv {
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my $op = shift;
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my $gv = $op->gv;
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$top = [$gv->STASH->NAME, '$', $gv->NAME];
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process($top, $op->private & OPpLVAL_INTRO ? "intro" : "used");
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}
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sub pp_gv {
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my $op = shift;
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my $gv = $op->gv;
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$top = [$gv->STASH->NAME, "*", $gv->NAME];
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process($top, $op->private & OPpLVAL_INTRO ? "intro" : "used");
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}
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sub pp_const {
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my $op = shift;
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my $sv = $op->sv;
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$top = ["?", "",
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(class($sv) ne "SPECIAL" && $sv->FLAGS & SVf_POK) ? $sv->PV : "?"];
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}
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sub pp_method {
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my $op = shift;
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$top = ["(method)", "->".$top->[1], $top->[2]];
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}
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sub pp_entersub {
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my $op = shift;
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if ($top->[1] eq "m") {
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process($top, "meth");
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} else {
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process($top, "subused");
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}
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$top = UNKNOWN;
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}
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#
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# Stuff for cross referencing definitions of variables and subs
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#
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sub B::GV::xref {
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my $gv = shift;
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my $cv = $gv->CV;
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if ($$cv) {
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#return if $done{$$cv}++;
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$file = $gv->FILEGV->SV->PV;
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$line = $gv->LINE;
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process([$gv->STASH->NAME, "&", $gv->NAME], "subdef");
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push(@todo, $cv);
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}
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my $form = $gv->FORM;
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if ($$form) {
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return if $done{$$form}++;
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$file = $gv->FILEGV->SV->PV;
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$line = $gv->LINE;
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process([$gv->STASH->NAME, "", $gv->NAME], "formdef");
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}
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}
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sub xref_definitions {
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my ($pack, %exclude);
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return if $nodefs;
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$subname = "(definitions)";
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foreach $pack (qw(B O AutoLoader DynaLoader Config DB VMS
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strict vars FileHandle Exporter Carp)) {
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$exclude{$pack."::"} = 1;
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}
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no strict qw(vars refs);
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walksymtable(\%{"main::"}, "xref", sub { !defined($exclude{$_[0]}) });
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}
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sub output {
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return if $raw;
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my ($file, $subname, $pack, $name, $ev, $perfile, $persubname,
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$perpack, $pername, $perev);
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foreach $file (sort(keys(%table))) {
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$perfile = $table{$file};
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print "File $file\n";
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foreach $subname (sort(keys(%$perfile))) {
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$persubname = $perfile->{$subname};
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print " Subroutine $subname\n";
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foreach $pack (sort(keys(%$persubname))) {
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$perpack = $persubname->{$pack};
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print " Package $pack\n";
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foreach $name (sort(keys(%$perpack))) {
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$pername = $perpack->{$name};
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my @lines;
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foreach $ev (qw(intro formdef subdef meth subused used)) {
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$perev = $pername->{$ev};
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if (defined($perev) && @$perev) {
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my $code = $code{$ev};
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push(@lines, map("$code$_", @$perev));
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}
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}
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printf " %-16s %s\n", $name, join(", ", @lines);
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}
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}
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}
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}
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}
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sub compile {
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my @options = @_;
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my ($option, $opt, $arg);
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OPTION:
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while ($option = shift @options) {
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if ($option =~ /^-(.)(.*)/) {
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$opt = $1;
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$arg = $2;
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} else {
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unshift @options, $option;
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last OPTION;
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}
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if ($opt eq "-" && $arg eq "-") {
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shift @options;
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last OPTION;
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} elsif ($opt eq "o") {
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$arg ||= shift @options;
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open(STDOUT, ">$arg") or return "$arg: $!\n";
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} elsif ($opt eq "d") {
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$nodefs = 1;
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} elsif ($opt eq "r") {
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$raw = 1;
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} elsif ($opt eq "D") {
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$arg ||= shift @options;
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foreach $arg (split(//, $arg)) {
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if ($arg eq "o") {
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B->debug(1);
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} elsif ($arg eq "O") {
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$debug_op = 1;
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} elsif ($arg eq "t") {
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$debug_top = 1;
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}
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}
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}
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}
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if (@options) {
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return sub {
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my $objname;
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xref_definitions();
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foreach $objname (@options) {
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$objname = "main::$objname" unless $objname =~ /::/;
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eval "xref_object(\\&$objname)";
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die "xref_object(\\&$objname) failed: $@" if $@;
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}
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output();
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}
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} else {
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return sub {
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xref_definitions();
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xref_main();
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output();
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}
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}
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}
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1;
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