Horton

Re: casting operand to proper type in BlockIdGetBlockNumber

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Zhihong Yu <zyu@yugabyte.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2022-03-03T17:29:37Z
Lists: pgsql-hackers 
Hi,

On 2022-03-03 12:13:40 -0500, Tom Lane wrote:
> Zhihong Yu <zyu@yugabyte.com> writes:
> > On Thu, Mar 3, 2022 at 8:24 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> >> Oh, I misread this as a compile-time warning, but it must be from ASAN.
> >> Was the test case one of your own, or just our normal regression tests?
> 
> > The Jenkins test is ported from contrib/postgres_fdw/sql/postgres_fdw.sql -
> > so theoretically PG would see the same error for clang12 on Alma.
> 
> Hmph.  I tried enabling -fsanitize=undefined here, and I get some
> complaints about passing null pointers to memcmp and the like, but
> nothing about this shift (tested with clang 12.0.1 on RHEL8 as well
> as clang 13.0.0 on Fedora 35).

We should fix these passing-null-pointer cases...


> What compiler switches are being used exactly?

FWIW, I've successfully used:
-Og -fsanitize=alignment,undefined -fno-sanitize=nonnull-attribute -fno-sanitize=float-cast-overflow -fno-sanitize-recover=all

Need to manually add -ldl, because -fsanitize breaks our dl test (it uses
dlopen, but not dlsym). Was planning to submit a fix for that...

Greetings,

Andres Freund

Commits

  1. Tighten overflow checks in tidin().

  2. Remove some pointless code in block.h.

  3. Fix bogus casting in BlockIdGetBlockNumber().

  4. Clean up assorted failures under clang's -fsanitize=undefined checks.