Mercurial > hg > octave-nkf > gnulib-hg
changeset 17119:973b259ceb42
manywarnings: cater to more gcc infelicities
Some versions of gcc (at least 4.2.1) noisily warn if
-Wuninitialized is given without -O; in isolation, configure
learns that the warning option is supported, but when later
compiling with -Werror, this makes builds fail. If the
option will have no effect for the configured choice of
$CFLAGS, then it is not worth including in the set.
* m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Add test for
-Wuninitialized without -O.
Signed-off-by: Eric Blake <eblake@redhat.com>
author | Eric Blake <eblake@redhat.com> |
---|---|
date | Thu, 06 Sep 2012 15:29:53 -0600 |
parents | 00956ff1864c |
children | ac32fde6df85 |
files | ChangeLog m4/manywarnings.m4 |
diffstat | 2 files changed, 31 insertions(+), 7 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2012-10-02 Eric Blake <eblake@redhat.com> + + manywarnings: cater to more gcc infelicities + * m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Add test for + -Wuninitialized without -O. + 2012-10-01 Ed Maste <emaste@freebsd.org> (tiny change) select, poll tests: Make setsockopt invocation effective.
--- a/m4/manywarnings.m4 +++ b/m4/manywarnings.m4 @@ -1,4 +1,4 @@ -# manywarnings.m4 serial 4 +# manywarnings.m4 serial 5 dnl Copyright (C) 2008-2012 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -35,14 +35,12 @@ # make sure your gcc understands it. AC_DEFUN([gl_MANYWARN_ALL_GCC], [ - dnl First, check if -Wno-missing-field-initializers is needed. - dnl -Wmissing-field-initializers is implied by -W, but that issues - dnl warnings with GCC version before 4.7, for the common idiom - dnl of initializing types on the stack to zero, using { 0, } + dnl First, check for some issues that only occur when combining multiple + dnl gcc warning categories. AC_REQUIRE([AC_PROG_CC]) if test -n "$GCC"; then - dnl First, check -W -Werror -Wno-missing-field-initializers is supported + dnl Check if -W -Werror -Wno-missing-field-initializers is supported dnl with the current $CC $CFLAGS $CPPFLAGS. AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported]) AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [ @@ -77,8 +75,24 @@ ]) AC_MSG_RESULT([$gl_cv_cc_nomfi_needed]) fi + + dnl Next, check if -Werror -Wuninitialized is useful with the + dnl user's choice of $CFLAGS; some versions of gcc warn that it + dnl has no effect if -O is not also used + AC_MSG_CHECKING([whether -Wuninitialized is supported]) + AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [ + gl_save_CFLAGS="$CFLAGS" + CFLAGS="$CFLAGS -Werror -Wuninitialized" + AC_COMPILE_IFELSE( + [AC_LANG_PROGRAM([[]], [[]])], + [gl_cv_cc_uninitialized_supported=yes], + [gl_cv_cc_uninitialized_supported=no]) + CFLAGS="$gl_save_CFLAGS"]) + AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported]) + fi + # List all gcc warning categories. gl_manywarn_set= for gl_manywarn_item in \ -W \ @@ -197,10 +211,14 @@ gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item" done - # Disable the missing-field-initializers warning if needed + # Disable specific options as needed. if test "$gl_cv_cc_nomfi_needed" = yes; then gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers" fi + if test "$gl_cv_cc_uninitialized_supported" = no; then + gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized" + fi + $1=$gl_manywarn_set ])