DAVEM TPF grant#2 report #149,#150,#151

(this report covers 3 weeks)

I've gotten a bit behind on logging and reporting my hours recently - in
particular I spent 4 days at the p5p hackathon, but mainly forgot to log
any hours.

Anyway, of the logged stuff, I fixed a few tickets and freed up
some uses of SV flag bits, mainly by eliminating obscure uses.

I've also been looking into whether the lexer's token recogniser
(keywords.c) could be done in a different way: the current approach, as
used for the last 10 years, generates a custom code-driven trie, which uses
very few CPU instructions; but these days branch prediction is more important,
and that code style kills branch prediction. I suspect that a data-driven
trie will perform better now.

2016/11/07
     2:24 [perl #129997] heap-use-after-free sv_catpvn_flags() within Perl_do_vop

2016/11/08
     0:37 [perl #129997] heap-use-after-free sv_catpvn_flags() within Perl_do_vop
     0:22 process p5p mailbox
     3:01 [perl #129991] Assertion failure in S_aassign_copy_common

2016/11/09
     0:50 [perl #129991] Assertion failure in S_aassign_copy_common
     0:07 [perl #129140] attempting double-free Perl_safesysfree util.c:388
     0:20 [perl #129997] heap-use-after-free sv_catpvn_flags() within Perl_do_vop

2016/11/10
     4:00 eliminate some ugly SV flag usages

2016/11/12
     4:00 eliminate some ugly SV flag usages

# ----

# ----

2016/11/21
     0:43 process p5p mailbox
     3:56 [perl #130132] Bleadperl breaks Date-Manip

2016/11/22
     0:14 process p5p mailbox
     2:03 [perl #130132] Bleadperl breaks Date-Manip

2016/11/23
     2:00 [perl #130132] Bleadperl breaks Date-Manip

2016/11/24
     0:11 process p5p mailbox
     2:09 optimise undef assignment
     0:45 [perl #130132] Bleadperl breaks Date-Manip

2016/11/25
     0:15 process p5p mailbox

2016/11/27
     4:00 performance of keywords.c
     1:00 [perl #130188] crash on return from substitution in subroutine


SUMMARY:
      0:07 [perl #129140] attempting double-free Perl_safesysfree util.c:388
      3:51 [perl #129991] Assertion failure in S_aassign_copy_common
      3:21 [perl #129997] heap-use-after-free sv_catpvn_flags() within Perl_do_vop
      8:44 [perl #130132] Bleadperl breaks Date-Manip
      1:00 [perl #130188] crash on return from substitution in subroutine
      8:00 eliminate some ugly SV flag usages
      2:09 optimise undef assignment
      4:00 performance of keywords.c
      1:45 process p5p mailbox
    ------
     32:57 TOTAL (HH::MM)


-- 
My Dad used to say 'always fight fire with fire', which is probably why
he got thrown out of the fire brigade.

• DAVEM TPF grant#2 report #149,#150,#151 by Dave Mitchell
• Re: DAVEM TPF grant#2 report #149,#150,#151 by Karl Williamson
• Re: DAVEM TPF grant#2 report #149,#150,#151 by Dave Mitchell
• Re: DAVEM TPF grant#2 report #149,#150,#151 by Sawyer X