c8h4/postgresql
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add -Wshadow=compatible-local to the standard compilation flags

Browse source 
Since cd4e8caaa, we've been able to build the source tree with
-Wshadow=compatible-local without any warnings.  Lots of work was done by
Justin Pryzby and I (David) to get all our code to compile warning free
with that flag.  In that process, 2 bugs (16d69ec29 and af7d270dd) were
discovered and fixed.  Additionally, "git log --grep=shadow" shows that
there is no shortage of other bugs that have been fixed over the years
which were caused by variable shadowing.

In light of the above, it seems very much worthwhile to add at least
-Wshadow=compatible-local to our standard compilation flags.  We *may*
want to go further and take this to -Wshadow=local in the future, but
we're not ready for that today, so let's add -Wshadow=compatible-local now
to help make sure we don't introduce further local variable shadowing.

Author: Andres Freund
Discussion: https://postgr.es/m/20221006003920.6xlqaoccxwisza5k@awork3.anarazel.de
This commit is contained in:
David Rowley 2022-10-07 16:50:31 +13:00
parent 80ef926758
commit 0fe954c285
3 changed files with 94 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

91
configure vendored
View file

@ -5852,6 +5852,97 @@ if test x"$pgac_cv_prog_CXX_cxxflags__Wcast_function_type" = x"yes"; then
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CC} supports -Wshadow=compatible-local, for CFLAGS" >&5
$as_echo_n "checking whether ${CC} supports -Wshadow=compatible-local, for CFLAGS... " >&6; }
if ${pgac_cv_prog_CC_cflags__Wshadow_compatible_local+:} false; then :
$as_echo_n "(cached) " >&6
else
pgac_save_CFLAGS=$CFLAGS
pgac_save_CC=$CC
CC=${CC}
CFLAGS="${CFLAGS} -Wshadow=compatible-local"
ac_save_c_werror_flag=$ac_c_werror_flag
ac_c_werror_flag=yes
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
pgac_cv_prog_CC_cflags__Wshadow_compatible_local=yes
else
pgac_cv_prog_CC_cflags__Wshadow_compatible_local=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"
CC="$pgac_save_CC"
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_prog_CC_cflags__Wshadow_compatible_local" >&5
$as_echo "$pgac_cv_prog_CC_cflags__Wshadow_compatible_local" >&6; }
if test x"$pgac_cv_prog_CC_cflags__Wshadow_compatible_local" = x"yes"; then
CFLAGS="${CFLAGS} -Wshadow=compatible-local"
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CXX} supports -Wshadow=compatible-local, for CXXFLAGS" >&5
$as_echo_n "checking whether ${CXX} supports -Wshadow=compatible-local, for CXXFLAGS... " >&6; }
if ${pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local+:} false; then :
$as_echo_n "(cached) " >&6
else
pgac_save_CXXFLAGS=$CXXFLAGS
pgac_save_CXX=$CXX
CXX=${CXX}
CXXFLAGS="${CXXFLAGS} -Wshadow=compatible-local"
ac_save_cxx_werror_flag=$ac_cxx_werror_flag
ac_cxx_werror_flag=yes
ac_ext=cpp
ac_cpp='$CXXCPP $CPPFLAGS'
ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
if ac_fn_cxx_try_compile "$LINENO"; then :
pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local=yes
else
pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local=no
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
ac_ext=c
ac_cpp='$CPP $CPPFLAGS'
ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
ac_compiler_gnu=$ac_cv_c_compiler_gnu
ac_cxx_werror_flag=$ac_save_cxx_werror_flag
CXXFLAGS="$pgac_save_CXXFLAGS"
CXX="$pgac_save_CXX"
fi
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local" >&5
$as_echo "$pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local" >&6; }
if test x"$pgac_cv_prog_CXX_cxxflags__Wshadow_compatible_local" = x"yes"; then
CXXFLAGS="${CXXFLAGS} -Wshadow=compatible-local"
fi
# This was included in -Wall/-Wformat in older GCC versions
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ${CC} supports -Wformat-security, for CFLAGS" >&5

2
configure.ac
View file

@ -508,6 +508,8 @@ if test "$GCC" = yes -a "$ICC" = no; then
PGAC_PROG_CXX_CFLAGS_OPT([-Wimplicit-fallthrough=3])
PGAC_PROG_CC_CFLAGS_OPT([-Wcast-function-type])
PGAC_PROG_CXX_CFLAGS_OPT([-Wcast-function-type])
PGAC_PROG_CC_CFLAGS_OPT([-Wshadow=compatible-local])
PGAC_PROG_CXX_CFLAGS_OPT([-Wshadow=compatible-local])
# This was included in -Wall/-Wformat in older GCC versions
PGAC_PROG_CC_CFLAGS_OPT([-Wformat-security])
PGAC_PROG_CXX_CFLAGS_OPT([-Wformat-security])

1
meson.build
View file

@ -1709,6 +1709,7 @@ common_warning_flags = [
'-Wmissing-format-attribute',
'-Wimplicit-fallthrough=3',
'-Wcast-function-type',
'-Wshadow=compatible-local',
# This was included in -Wall/-Wformat in older GCC versions
'-Wformat-security',
]