Обсуждение: Build error in Solaris

"=?utf-8?B?V2VpIFN1bg==?=" <936739278@qq.com> writes:
> When I built the latest code for branch REL_10_STABLE on the Solairs,
> the following error occurred:
> ------------------------------------------------------
> "plperl.c", line 669: syntax error before or at: if
> "plperl.c", line 669: undefined symbol: _sv
> "plperl.c", line 669: left operand of "->" must be pointer to struct/union
> "plperl.c", line 669: warning: improper pointer/integer combination: arg #2
> "plperl.c", line 669: syntax error before or at: else
> "plperl.c", line 670: warning: statement not reached
> "plperl.c", line 678: cannot recover from previous errors
> cc: acomp failed for plperl.c
> gmake: *** [plperl.o] Error 2
> ------------------------------------------------------

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

Revision history for Devel-PPPort

3.64 - 2022-02-01
  * Fix: better support for STMT_START / STMT_END definition
  * Fix: Only use '-Wdeclaration-after-statement' if possible

which if not a smoking gun is at least firearm-adjacent.

            regards, tom lane

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