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Postings from July 2013
Hi,
I cannot reproduce the issue in S_finalize_op on blead[1]. It is
possible that it has been "fixed" somehow (or we got different
architectures).
On the other hand, I can reproduce the crash caused by:
perl -e'eval "sub{".q"$a+"x shift . "}"' 500000
I have attached a prototype patch that solves the problem (at least for
me). With the patch applied, I can run it with up to at least 2M
without it crashing - I have not tested beyond that because perl starts
to use >= 4GB of RAM around the 2M mark.
A more memory friendly test case is definitely welcome. :)
For the reviewer(s): the patch is much easier to read by ignoring space
changes[2]. It re-uses the basic principe of the DEFER marco used in
the peephole optimizer. The "major" difference is that it uses a
fixed-size stack rather than a fixed-size queue. The size of the queue
did not seem to matter a lot (even with MAX_DEFERRED reduced to 2 was
the crash avoided in original test case).
The test suite showed no regression, perl was configured with:
./Configure -des -Dusedevel
~Niels
[1] I have been using code suggested by Dave Mitchell (rewritten as a
perl one-liner)
./perl -e 'my $code = q[my $i = 0; if ($i) { print } ] . "\n";'
-e '$code .= q[ elsif ($i) { print } ] . "\n" for 1..$ARGV[0];'
-e 'eval $code' 10000
[2] Compare
$ git diff --ignore-all-space --stat
op.c | 37 [...]
1 file changed, 34 insertions(+), 3 deletions(-)
versus.
$ git diff --stat
op.c | 141 [...]
1 file changed, 86 insertions(+), 55 deletions(-)
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