Date: Tue, 9 Apr 2019 18:15:57 +0200
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
To: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: Tom Lane <tgl@sss.pgh.pa.us>,
	Andrew Dunstan <andrew.dunstan@2ndquadrant.com>,
	Andres Freund <andres@anarazel.de>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	John Naylor <john.naylor@2ndquadrant.com>,
	Jeff Janes <jeff.janes@gmail.com>,
	Nikita Glukhov <n.gluhov@postgrespro.ru>,
	Oleg Bartunov <obartunov@postgrespro.ru>,
	Michael Paquier <michael@paquier.xyz>,
	Stas Kelvich <s.kelvich@postgrespro.ru>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>,
	Thomas Munro <thomas.munro@enterprisedb.com>,
	David Steele <david@pgmasters.net>,
	Robert Haas <robertmhaas@gmail.com>,
	Pavel Stehule <pavel.stehule@gmail.com>
Subject: Re: jsonpath
Message-ID: <20190409161557.xwc4xwqeaimxcb4d@development>
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On Sun, Apr 07, 2019 at 03:03:58AM +0300, Alexander Korotkov wrote:
>On Sun, Apr 7, 2019 at 2:37 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Alexander Korotkov <a.korotkov@postgrespro.ru> writes:
>> > Thus, contents of unused function makes test fail or pass.  So far, it
>> > looks like a compiler bug.  Any thoughts?
>>
>> Yeah :-(.  The fact that we've not seen a similar failure on any other
>> machines points in that direction, too.  Maybe it's some other aspect
>> of the machine's toolchain, like flex or bison, but that's not that
>> much different from our standpoint.
>>
>> There's a lot of stuff I don't especially like about jsonpath_scan,
>> for instance I think the "init" arguments to resizeString etc are
>> a pretty error-prone and unmaintainable way to do things.  But
>> I don't see anything that looks like it'd be a portability hazard
>> that would explain this.
>>
>> I still have a nagging feeling that there's a wild store somewhere
>> in here, but I don't know how to find it based on the limited
>> evidence we've got.
>
>Yeah, it might be not because compiler error.  It might depend on
>memory layout.  So existence of extra function changes memory layout
>and, in turn, causes an error.  I will try to disassemble
>jsonpath_scan.o and see whether content of yyparse2 influences
>assembly of other functions.
>

Have you tried other compiler version / different optimization level? Or
running it under valgrind. Not sure how difficult that is on Windows.


regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services