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From: Zhihong Yu <[email protected]>
To: Noah Misch <[email protected]>
Cc: Tom Lane <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Subject: Re: null iv parameter passed to combo_init()
Date: Sun, 9 Jan 2022 12:38:23 -0800
Message-ID: <CALNJ-vSf3zDrYm6RqoKqD8CkM9J97mmKroN2HD5ryEO6V6oT6Q@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CALNJ-vSBb2Ees=KB0frYBh7foK-QNZMbK7Vz66bUJa09D+CHAw@mail.gmail.com>
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	<CALNJ-vTh9BXARHg3iaCAzr97Fws2W5aR6nRPJfT4u3VdKDzRTQ@mail.gmail.com>
	<[email protected]>
	<[email protected]>
	<CALNJ-vTuaO+6hM4wY2aE0V7WdB56bwTXDp50Bn2U1ggmonVGbA@mail.gmail.com>
	<[email protected]>

On Sun, Jan 9, 2022 at 8:48 AM Noah Misch <[email protected]> wrote:

> On Sun, Jan 09, 2022 at 04:37:32AM -0800, Zhihong Yu wrote:
> > On Sat, Jan 8, 2022 at 11:32 PM Tom Lane <[email protected]> wrote:
> > > Noah Misch <[email protected]> writes:
> > > > On further thought, I would write it this way:
> > >
> > > > -             else
> > > > +             else if (ivlen != 0)
> > > >                       memcpy(ivbuf, iv, ivlen);
> > >
> > > FWIW, I liked the "ivlen > 0" formulation better.  They should be
> > > equivalent, because ivlen is unsigned, but it just seems like "> 0"
> > > is more natural.
>
> If I were considering the one code site in isolation, I'd pick "ivlen > 0".
> But of the four sites identified so far, three have signed length
> variables.
> Since we're likely to get more examples of this pattern, some signed and
> some
> unsigned, I'd rather use a style that does the optimal thing whether or not
> the variable is signed.  What do you think?
>
> > Patch v4 is attached.
>
> Does this pass the test procedure shown upthread?
>
Hi,
I installed gcc 4.9.3

When I ran:
./configure CFLAGS='-fsanitize=undefined
-fsanitize-undefined-trap-on-error'

I saw:

configure:3977: $? = 0
configure:3966: gcc -V >&5
gcc: error: unrecognized command line option '-V'
gcc: fatal error: no input files
compilation terminated.
configure:3977: $? = 1
configure:3966: gcc -qversion >&5
gcc: error: unrecognized command line option '-qversion'
gcc: fatal error: no input files
compilation terminated.
configure:3977: $? = 1
configure:3997: checking whether the C compiler works
configure:4019: gcc -fsanitize=undefined -fsanitize-undefined-trap-on-error
  conftest.c  >&5
gcc: error: unrecognized command line option
'-fsanitize-undefined-trap-on-error'
configure:4023: $? = 1
configure:4061: result: no

I wonder if a higher version gcc is needed.

FYI


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