Re: Keep elog(ERROR) and ereport(ERROR) calls in the cold path

On Tue, Nov 24, 2020 at 10:06 AM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
>
> On Tue, 24 Nov 2020 at 09:36, David Rowley <dgrowleyml(at)gmail(dot)com> wrote:
> > Well, that makes it look pretty good. If we can get 10-15% on some
> > machines without making things slower on any other machines, then that
> > seems like a good win to me.
>
> Pushed.
>
> Thank you both for reviewing this.
>
> David
>
>

Hmmm, unfortunately this seems to break my build ...

make[1]: Entering directory `/space2/pg13/postgres/src'
make -C common all
make[2]: Entering directory `/space2/pg13/postgres/src/common'
gcc -std=gnu99 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing
-fwrapv -fexcess-precision=standard -g -O0 -DFRONTEND -I.
-I../../src/common -I../../src/include -D_GNU_SOURCE -DVAL_CC="\"gcc
-std=gnu99\"" -DVAL_CPPFLAGS="\"-D_GNU_SOURCE\"" -DVAL_CFLAGS="\"-Wall
-Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement
-Werror=vla -Wendif-labels -Wmissing-format-attribute
-Wformat-security -fno-strict-aliasing -fwrapv
-fexcess-precision=standard -g -O0\"" -DVAL_CFLAGS_SL="\"-fPIC\""
-DVAL_LDFLAGS="\"-Wl,--as-needed
-Wl,-rpath,'/usr/local/pg14/lib',--enable-new-dtags\""
-DVAL_LDFLAGS_EX="\"\"" -DVAL_LDFLAGS_SL="\"\""
-DVAL_LIBS="\"-lpgcommon -lpgport -lpthread -lz -lreadline -lrt -ldl
-lm \"" -c -o archive.o archive.c
In file included from ../../src/include/postgres_fe.h:25:0,
from archive.c:19:
../../src/include/c.h:198:49: error: missing binary operator before token "("
#if defined(__has_attribute) && __has_attribute (cold)
^
../../src/include/c.h:204:49: error: missing binary operator before token "("
#if defined(__has_attribute) && __has_attribute (hot)
^
make[2]: *** [archive.o] Error 1
make[2]: Leaving directory `/space2/pg13/postgres/src/common'
make[1]: *** [all-common-recurse] Error 2
make[1]: Leaving directory `/space2/pg13/postgres/src'
make: *** [world-src-recurse] Error 2

[gregn(at)localhost postgres]$ gcc --version
gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
Copyright (C) 2015 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.

I think your commit needs to be fixed based on the following documentation:

https://gcc.gnu.org/onlinedocs/cpp/_005f_005fhas_005fattribute.html#g_t_005f_005fhas_005fattribute

"The first ‘#if’ test succeeds only when the operator is supported by
the version of GCC (or another compiler) being used. Only when that
test succeeds is it valid to use __has_attribute as a preprocessor
operator. As a result, combining the two tests into a single
expression as shown below would only be valid with a compiler that
supports the operator but not with others that don’t. "

(Thanks to my colleague Peter Smith for finding the doc explanation)

Regards,
Greg Nancarrow
Fujitsu Australia