Re: Build error in Solaris

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: ilmari <ilmari(at)ilmari(dot)org>
Cc: Wei Sun <936739278(at)qq(dot)com>, pgsql-bugs <pgsql-bugs(at)lists(dot)postgresql(dot)org>
Subject: Re: Build error in Solaris
Date: 2022-02-08 21:53:01
Message-ID: 1290986.1644357181@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-bugs

I wrote:
> Hm. I saw something similar on my old dinosaur pademelon, but wrote it
> off as "they don't care about pre-C99 compilers anymore". But now I
> dug into ppport.h a bit more, and I think it's actually busted for
> non-gcc compilers: eval_pv expands into something that tries to use
> STMT_START/STMT_END inside a plain parenthesized expression (via
> croak_sv).

> Maybe the bleeding edge Devel::PPPort would do better? I see

Nope, 3.64 is also broken.

I traced this to this stanza, originally added in Devel-PPPort 3.54:

/* Older Perl versions have broken croak_on_error=1 */
#if (PERL_BCDVERSION < 0x5031002)
# ifdef eval_pv
# undef eval_pv
# if defined(PERL_USE_GCC_BRACE_GROUPS)
# define eval_pv(p, croak_on_error) ({ SV *_sv = Perl_eval_pv(aTHX_ p, 0); D_PPP_CROAK_IF_ERROR(croak_on_error); _sv; })
# else
# define eval_pv(p, croak_on_error) ((PL_Sv = Perl_eval_pv(aTHX_ p, 0)), D_PPP_CROAK_IF_ERROR(croak_on_error), PL_Sv)
# endif
# endif
#endif

D_PPP_CROAK_IF_ERROR goes to croak_sv which, in older Perl
versions, produces a statement block. So anything that won't
accept gcc-like statements within expressions blows up.

Now, we don't actually *care* about the case this is trying
to fix, because all our eval_pv usages pass constant-FALSE
for croak_on_error. (Possibly not unrelated to the bug
implied by the above comment ... but I digress.) Therefore,
pending a resolution to the issue I just filed [1], I suggest
that we just dike this stanza out of our copy of ppport.h.

regards, tom lane

[1] https://github.com/Dual-Life/Devel-PPPort/issues/216

In response to

Browse pgsql-bugs by date

  From Date Subject
Next Message Michael Paquier 2022-02-09 01:35:57 Re: BUG #17401: REINDEX TABLE CONCURRENTLY creates a race condition on a streaming replica
Previous Message Peter Geoghegan 2022-02-08 21:23:34 Re: BUG #17401: REINDEX TABLE CONCURRENTLY creates a race condition on a streaming replica