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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug sanitizer/65479] sanitizer stack trace missing frames past #0 on powerpc64
Date: Wed, 01 Apr 2015 01:14:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65479

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
Created attachment 35196
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35196&action=edit
Proof-of-concept patch.

Two problems are contributing to the failures in these tests:

1) a missing -fasynchronous-unwind-tables option; the option is necessary on
powerpc*-*-*-* to generate a full stack trace
2) a bug in the backtrace_qsort function introduced in r208403 that makes the
algorithm unstable (see also
http://gcc.gnu.org/ml/gcc-patches/2014-03/msg00342.html)

The attached proof-of-concept patch adds the missing option mentioned in (1)
and backs out the commit referenced in (2) as a proof of concept of fixing the
problem.  I'll try to come up with an approach that doesn't undo the
performance improvement in a subsequent patch.