Bug#754054: perl: FTBFS on mips: Bad mojo! at make_patchnum.pl line 111.

On Mon, Jul 07, 2014 at 08:00:37AM +0300, Niko Tyni wrote:
> Package: perl
> Version: 5.18.2-5
> Severity: serious
> X-Debbugs-Cc: [email protected]
> 
> The perl package failed to build on mips:
>  LD_LIBRARY_PATH=/build/perl\-sdOt09/perl\-5.18.2${LD_LIBRARY_PATH:+:}$LD_LIBRARY_PATH  ./miniperl -Ilib make_patchnum.pl
>  Bad mojo! at make_patchnum.pl line 111.

> This is reproducible on gabrielli.

A test case would be

  gabrielli% cat ~/t.pl
  print ( (q{foo'} =~ /[^']+'/) ?  "ok\n" : "not ok\n" );
  gabrielli% perl ~/t.pl
  ok
  gabrielli% ./miniperl ~/t.pl
  not ok

This is a shared build; the static build doesn't exhibit the bug and
passes the full test suite. The bug only shows up with -fPIC.

An educated guess narrowed it down to regcomp.c. The above test fails
when regcomp.c is built with gcc-4.9 at -O2 but works with gcc-4.9 at
-O0 and gcc-4.8 at -O2.

I'll patch the package to lower the optimization level of regcomp.c
for now.  Assuming a test build succeeds on gabrielli, I hope to upload
tomorrow.

Distilling a proper gcc bug report about this seems rather arduous, and
I don't really expect to get around to it. Help from the MIPS porters
on that would be appreciated.
-- 
Niko Tyni   [email protected]