Andres Freund <and...@2ndquadrant.com> writes: > On 2015-01-25 14:02:47 -0500, Tom Lane wrote: >> I've been looking for other instances of the problem Mark Wilding >> pointed out, about missing "volatile" markers on variables that >> are modified in PG_TRY blocks and then used in the PG_CATCH stanzas. >> There definitely are some. Current gcc versions do not warn about that.
> I think it's actually not a recent regression - in the past a lot of > spurious instances of these warnings have been fixed by simply tacking > on volatile on variables that didn't actually need it. Yeah, it's not. For years and years I just automatically stuck a "volatile" on anything gcc 2.95.3 complained about, so that's why there's so many volatiles there now. But I've not done that lately, and comparing what 2.95.3 warns about now with what a modern version says with -Wclobbered, it's clear that it's pretty much the same broken (and perhaps slightly machine-dependent) algorithm :-( >> This is scary as hell. I intend to go around and manually audit >> every single PG_TRY in the current source code, but that is obviously >> not a long-term solution. Anybody have an idea about how we might >> get trustworthy mechanical detection of this type of situation? > Not really, except convincing gcc to fix the inaccurate detection. Given > that there've been bugs open about this (IIRC one from you even) for > years I'm not holding my breath. I've completed the audit, and there were a total of only five places that need fixes (including the two I already patched over the weekend). It's mostly pretty new code too, which probably explains why we don't already have field reports of problems. Interestingly, plpython seems heavily *over* volatilized. Not sure whether to take some out there for consistency, or just leave it alone. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers