Re: More bogus alignment assumptions - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: More bogus alignment assumptions
Date
Msg-id 200103252141.QAA17423@candle.pha.pa.us
Whole thread Raw
In response to More bogus alignment assumptions  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> Following up on the recent bug report from Steve Nicolai, I spent a
> tedious hour groveling through all the warnings emitted by gcc with
> -Wcast-align.  (We ought to try to reduce the number of them, but that's
> a task for another day.)
> 
> I found seven places, in addition to the tuptoaster.c error originally
> identified by Steve, in which the code is assuming that a "char foo[N]"
> local variable will be aligned on better-than-char boundaries by the
> compiler.  All were inserted since 7.0.  All but one were inserted by
> Vadim in the new WAL code; the other one is in large-object support
> and is my fault :-(
> 
> I will fix these shortly, but I wanted to raise a flag to people:
> don't do that.  An array of X is not guaranteed to be aligned any
> better than an X is.

Added to TODO:
* Remove warnings created by -Wcast-align

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026
 


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: More bogus alignment assumptions
Next
From: Ryan Kirkpatrick
Date:
Subject: Re: Vaccuum Failure w/7.1beta4 on Linux/Sparc -- FALSE ALARM