Clean up compilation warnings coming from PL/Perl with clang-12~

clang-12 has introduced -Wcompound-token-split-by-macro, that is causing
a large amount of warnings when building PL/Perl because of its
interactions with upstream Perl.  This commit adds one -Wno to CFLAGS at
./configure time if the flag is supported by the compiler to silence all
those warnings.

This back-patches commit 9ff47ea41 into out-of-support branches,
pursuant to newly-established project policy.  The point is to
suppress scary-looking warnings so that people building these
branches needn't expend brain cells verifying that it's safe
to ignore the warnings.

Discussion: https://postgr.es/m/d0316012-ece7-7b7e-2d36-9c38cb77cb3b@enterprisedb.com
This commit is contained in:
Tom Lane 2021-12-12 18:06:15 -05:00
parent 87671beecf
commit ebd952f3f4
2 changed files with 75 additions and 0 deletions

67
configure vendored
View File

@ -4474,6 +4474,73 @@ fi
if test -n "$NOT_THE_CFLAGS"; then
CFLAGS="$CFLAGS -Wno-unused-command-line-argument"
fi
# Remove clang 12+'s compound-token-split-by-macro, as this causes a lot
# of warnings when building plperl because of Perl. Like previously, test
# for the positive form and add the negative form
NOT_THE_CFLAGS=""
{ $as_echo "$as_me:$LINENO: checking whether $CC supports -Wcompound-token-split-by-macro" >&5
$as_echo_n "checking whether $CC supports -Wcompound-token-split-by-macro... " >&6; }
if test "${pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro+set}" = set; then
$as_echo_n "(cached) " >&6
else
pgac_save_CFLAGS=$CFLAGS
CFLAGS="$pgac_save_CFLAGS -Wcompound-token-split-by-macro"
ac_save_c_werror_flag=$ac_c_werror_flag
ac_c_werror_flag=yes
cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
rm -f conftest.$ac_objext
if { (ac_try="$ac_compile"
case "(($ac_try" in
*\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
*) ac_try_echo=$ac_try;;
esac
eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
$as_echo "$ac_try_echo") >&5
(eval "$ac_compile") 2>conftest.er1
ac_status=$?
grep -v '^ *+' conftest.er1 >conftest.err
rm -f conftest.er1
cat conftest.err >&5
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); } && {
test -z "$ac_c_werror_flag" ||
test ! -s conftest.err
} && test -s conftest.$ac_objext; then
pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro=yes
else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro=no
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
ac_c_werror_flag=$ac_save_c_werror_flag
CFLAGS="$pgac_save_CFLAGS"
fi
{ $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro" >&5
$as_echo "$pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro" >&6; }
if test x"$pgac_cv_prog_cc_cflags__Wcompound_token_split_by_macro" = x"yes"; then
NOT_THE_CFLAGS="${NOT_THE_CFLAGS} -Wcompound-token-split-by-macro"
fi
if test -n "$NOT_THE_CFLAGS"; then
CFLAGS="$CFLAGS -Wno-compound-token-split-by-macro"
fi
# Similarly disable useless truncation warnings from gcc 8+
NOT_THE_CFLAGS=""
{ $as_echo "$as_me:$LINENO: checking whether $CC supports -Wformat-truncation" >&5

View File

@ -434,6 +434,14 @@ if test "$GCC" = yes -a "$ICC" = no; then
if test -n "$NOT_THE_CFLAGS"; then
CFLAGS="$CFLAGS -Wno-unused-command-line-argument"
fi
# Remove clang 12+'s compound-token-split-by-macro, as this causes a lot
# of warnings when building plperl because of Perl. Like previously, test
# for the positive form and add the negative form
NOT_THE_CFLAGS=""
PGAC_PROG_CC_VAR_OPT(NOT_THE_CFLAGS, [-Wcompound-token-split-by-macro])
if test -n "$NOT_THE_CFLAGS"; then
CFLAGS="$CFLAGS -Wno-compound-token-split-by-macro"
fi
# Similarly disable useless truncation warnings from gcc 8+
NOT_THE_CFLAGS=""
PGAC_PROG_CC_VAR_OPT(NOT_THE_CFLAGS, [-Wformat-truncation])