Package: perl-base
Version: 5.8.8-4
Severity: minor
Tags: patch
Hi,
when doing perl coverage analysis with the module Devel::Cover a deep recursion
warning usually happens:
Deep recursion on subroutine "B::Deparse::find_scope" at
/usr/lib/perl/5.8.8/B/Deparse.pm line 1321
For preventing this, I rewrote the find_scope function for using a queue
instead of doing recursions. My complete test set now runs without any deep
recursion error any more. I also made some benchmark analysis (twice for every
implementation) and it seems to run almost 10% faster now:
--- with recursion (old) ---
real 0m31.184s
user 0m29.490s
sys 0m0.460s
real 0m31.198s
user 0m29.494s
sys 0m0.448s
--- with queue of objects ---
real 0m30.052s
user 0m28.414s
sys 0m0.400s
real 0m30.277s
user 0m28.542s
sys 0m0.388s
--- with queue of references to objects (new) ---
real 0m29.969s
user 0m28.062s
sys 0m0.392s
real 0m29.609s
user 0m27.974s
sys 0m0.420s
I have not made any analysis on memory consumption yet. But using a queue
against recursion, should be better too.
Please include this in perl-base. It could be interesting for upstream too.
With kind regards,
Tobias Lorenz
-- System Information:
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'unstable'), (700, 'stable'), (1, 'experimental')
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Versions of packages perl-base depends on:
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perl-base recommends no packages.
-- no debconf information
1308,1322c1308,1327
< for (my $o=$op->first; $$o; $o=$o->sibling) {
< if ($o->name =~ /^pad.v$/ && $o->private & OPpLVAL_INTRO) {
< my $s = int($self->padname_sv($o->targ)->NVX);
< my $e = $self->padname_sv($o->targ)->IVX;
< $scope_st = $s if !defined($scope_st) || $s < $scope_st;
< $scope_en = $e if !defined($scope_en) || $e > $scope_en;
< }
< elsif (is_state($o)) {
< my $c = $o->cop_seq;
< $scope_st = $c if !defined($scope_st) || $c < $scope_st;
< $scope_en = $c if !defined($scope_en) || $c > $scope_en;
< }
< elsif ($o->flags & OPf_KIDS) {
< ($scope_st, $scope_en) =
< $self->find_scope($o, $scope_st, $scope_en)
---
> my @queue = (\$op);
> while(@queue) {
> $op = ${(shift(@queue))};
> for (my $o=$op->first; $$o; $o=$o->sibling) {
> if ($o->name =~ /^pad.v$/ && $o->private & OPpLVAL_INTRO) {
> my $s = int($self->padname_sv($o->targ)->NVX);
> my $e = $self->padname_sv($o->targ)->IVX;
> $scope_st = $s if !defined($scope_st) || $s < $scope_st;
> $scope_en = $e if !defined($scope_en) || $e > $scope_en;
> return ($scope_st, $scope_en);
> }
> elsif (is_state($o)) {
> my $c = $o->cop_seq;
> $scope_st = $c if !defined($scope_st) || $c < $scope_st;
> $scope_en = $c if !defined($scope_en) || $c > $scope_en;
> return ($scope_st, $scope_en);
> }
> elsif ($o->flags & OPf_KIDS) {
> push(@queue, \$o);
> }
