Re: Fix last unitialized memory warning

Tristan Partin <tristan@neon.tech>

From: "Tristan Partin" <tristan@neon.tech>
To: "Peter Eisentraut" <peter@eisentraut.org>, <pgsql-hackers@postgresql.org>
Date: 2023-08-08T15:14:57Z
Lists: pgsql-hackers

Attachments

On Tue Aug 8, 2023 at 5:20 AM CDT, Peter Eisentraut wrote:
> On 19.07.23 19:15, Tristan Partin wrote:
> > On Sun Jul 9, 2023 at 2:23 AM CDT, Peter Eisentraut wrote:
> >> On 06.07.23 15:41, Tristan Partin wrote:
> >> > On Thu Jul 6, 2023 at 3:21 AM CDT, Peter Eisentraut wrote:
> >> >> On 05.07.23 23:06, Tristan Partin wrote:
> >> >>> Thanks for following up. My system is Fedora 38. I can confirm 
> >> this is
> >> >>> still happening on master.
> >> >>>
> >> >>> $ gcc --version
> >> >>> gcc (GCC) 13.1.1 20230614 (Red Hat 13.1.1-4)
> >> >>> Copyright (C) 2023 Free Software Foundation, Inc.
> >> >>> This is free software; see the source for copying conditions.  
> >> There is NO
> >> >>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR 
> >> PURPOSE.
> >> >>> $ meson setup build --buildtype=release
> >> >>
> >> >> This buildtype turns on -O3 warnings.  We have usually opted against
> >> >> chasing warnings in -O3 level because there are often some
> >> >> false-positive uninitialized variable warnings with every new 
> >> compiler.
> >> >>
> >> >> Note that we have set the default build type to debugoptimized, for 
> >> that
> >> >> reason.
> >> > > Good to know, thanks.
> >> > > Regarding the original patch, do you think it is good to be applied?
> >>
> >> That patch looks reasonable.  But I can't actually reproduce the 
> >> warning, even with gcc-13.  I do get the warning from plpgsql.  Can 
> >> you show the warning you are seeing?
> > 
> > Here is the full warning that the original patch suppresses.
>
> I was able to reproduce the warning now on Fedora.  I agree with the patch
>
> -       PgBenchValue vargs[MAX_FARGS];
> +       PgBenchValue vargs[MAX_FARGS] = { 0 };
>
> I suggest to also do
>
>   typedef enum
>   {
> -       PGBT_NO_VALUE,
> +       PGBT_NO_VALUE = 0,
>
> to make clear that the initialization value is meant to be invalid.
>
> I also got the plpgsql warning that you showed earlier, but I couldn't 
> think of a reasonable way to fix that.

Applied in v2.

-- 
Tristan Partin
Neon (https://neon.tech)

Commits

  1. Fix erroneous -Werror=missing-braces on old GCC

  2. Fix last remaining uninitialized memory warnings