| Message ID | 2a5b17ba992abd2311da130c18a531f89c21ee79.1722604821.git.fweimer@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Turn on -Wimplicit-fallthrough | expand |
On 02/08/24 10:22, Florian Weimer wrote: > --- > Makeconfig | 3 +++ > config.make.in | 1 + > configure | 12 ++++++++++++ > configure.ac | 10 ++++++++++ > 4 files changed, 26 insertions(+) > > diff --git a/Makeconfig b/Makeconfig > index 2d4343b604..e90f612b96 100644 > --- a/Makeconfig > +++ b/Makeconfig > @@ -889,6 +889,9 @@ endif > > # Extra flags to pass to GCC. > +gccwarn := -Wall -Wwrite-strings -Wundef > +ifeq ($(enable-wimplicit-fallthrough),yes) > ++gccwarn += -Wimplicit-fallthrough > +endif > ifeq ($(enable-werror),yes) > +gccwarn += -Werror > endif > diff --git a/config.make.in b/config.make.in > index 36096881b7..4286a63269 100644 > --- a/config.make.in > +++ b/config.make.in > @@ -51,6 +51,7 @@ c++-cstdlib-header = @CXX_CSTDLIB_HEADER@ > c++-cmath-header = @CXX_CMATH_HEADER@ > c++-bits-std_abs-h = @CXX_BITS_STD_ABS_H@ > enable-werror = @enable_werror@ > +enable-wimplicit-fallthrough = @enable_wimplicit_fallthrough@ > > have-z-execstack = @libc_cv_z_execstack@ > have-protected-data = @libc_cv_protected_data@ > diff --git a/configure b/configure > index 1d543548cd..01a011d73f 100755 > --- a/configure > +++ b/configure > @@ -643,6 +643,7 @@ have_selinux > have_libcap > have_libaudit > LIBGD > +enable_wimplicit_fallthrough > libc_cv_cc_loop_to_function > libc_cv_cc_submachine > libc_cv_cc_nofma > @@ -7465,6 +7466,17 @@ if test $libc_cv_cc_loop_to_function = yes; then > fi > > > +if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ > + || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" > +then > + echo HOHOHO > + enable_wimplicit_fallthrough=yes > +else > + echo BADBADBAD > + enable_wimplicit_fallthrough=no > +fi > + > + > { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5 > printf %s "checking for libgd... " >&6; } > if test "$with_gd" != "no"; then > diff --git a/configure.ac b/configure.ac > index 9cbc0bf68f..c686ea4b97 100644 > --- a/configure.ac > +++ b/configure.ac > @@ -1468,6 +1468,16 @@ if test $libc_cv_cc_loop_to_function = yes; then > fi > AC_SUBST(libc_cv_cc_loop_to_function) > > +dnl GCC uses --help=warnings, Clang uses -print-diagnostic-options. > +if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ > + || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" > +then > + enable_wimplicit_fallthrough=yes > +else > + enable_wimplicit_fallthrough=no > +fi > +AC_SUBST(enable_wimplicit_fallthrough) > + > dnl Check whether we have the gd library available. > AC_MSG_CHECKING(for libgd) > if test "$with_gd" != "no"; then Why not AC_CACHE_CHECK and LIBC_CONFIG_VAR: AC_CACHE_CHECK([for implicit fallthrough warning], libc_cv_implicit_fallthrough_warning, libc_cv_implicit_fallthrough_warning=no if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" then libc_cv_implicit_fallthrough_warning=yes fi) LIBC_CONFIG_VAR([enable-wimplicit-fallthrough], [$libc_cv_implicit_fallthrough_warning]) ?
On Aug 07 2024, Adhemerval Zanella Netto wrote: > AC_CACHE_CHECK([for implicit fallthrough warning], > libc_cv_implicit_fallthrough_warning, > libc_cv_implicit_fallthrough_warning=no > if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ > || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" This should check directly whether $CC accepts the option.
On 07/08/24 09:28, Andreas Schwab wrote: > On Aug 07 2024, Adhemerval Zanella Netto wrote: > >> AC_CACHE_CHECK([for implicit fallthrough warning], >> libc_cv_implicit_fallthrough_warning, >> libc_cv_implicit_fallthrough_warning=no >> if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ >> || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" > > This should check directly whether $CC accepts the option. > Why exactly we can't use AC_CACHE_CHECK in this case?
* Adhemerval Zanella Netto: > On 07/08/24 09:28, Andreas Schwab wrote: >> On Aug 07 2024, Adhemerval Zanella Netto wrote: >> >>> AC_CACHE_CHECK([for implicit fallthrough warning], >>> libc_cv_implicit_fallthrough_warning, >>> libc_cv_implicit_fallthrough_warning=no >>> if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ >>> || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" >> >> This should check directly whether $CC accepts the option. >> > > Why exactly we can't use AC_CACHE_CHECK in this case? I think Andreas just wants to check the option directly (clang needs -Werror, didn't figure that out before), rather than searching for it in help output. I'll see if I can produce a patch along those lines. Thanks, Florian
diff --git a/Makeconfig b/Makeconfig index 2d4343b604..e90f612b96 100644 --- a/Makeconfig +++ b/Makeconfig @@ -889,6 +889,9 @@ endif # Extra flags to pass to GCC. +gccwarn := -Wall -Wwrite-strings -Wundef +ifeq ($(enable-wimplicit-fallthrough),yes) ++gccwarn += -Wimplicit-fallthrough +endif ifeq ($(enable-werror),yes) +gccwarn += -Werror endif diff --git a/config.make.in b/config.make.in index 36096881b7..4286a63269 100644 --- a/config.make.in +++ b/config.make.in @@ -51,6 +51,7 @@ c++-cstdlib-header = @CXX_CSTDLIB_HEADER@ c++-cmath-header = @CXX_CMATH_HEADER@ c++-bits-std_abs-h = @CXX_BITS_STD_ABS_H@ enable-werror = @enable_werror@ +enable-wimplicit-fallthrough = @enable_wimplicit_fallthrough@ have-z-execstack = @libc_cv_z_execstack@ have-protected-data = @libc_cv_protected_data@ diff --git a/configure b/configure index 1d543548cd..01a011d73f 100755 --- a/configure +++ b/configure @@ -643,6 +643,7 @@ have_selinux have_libcap have_libaudit LIBGD +enable_wimplicit_fallthrough libc_cv_cc_loop_to_function libc_cv_cc_submachine libc_cv_cc_nofma @@ -7465,6 +7466,17 @@ if test $libc_cv_cc_loop_to_function = yes; then fi +if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ + || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" +then + echo HOHOHO + enable_wimplicit_fallthrough=yes +else + echo BADBADBAD + enable_wimplicit_fallthrough=no +fi + + { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for libgd" >&5 printf %s "checking for libgd... " >&6; } if test "$with_gd" != "no"; then diff --git a/configure.ac b/configure.ac index 9cbc0bf68f..c686ea4b97 100644 --- a/configure.ac +++ b/configure.ac @@ -1468,6 +1468,16 @@ if test $libc_cv_cc_loop_to_function = yes; then fi AC_SUBST(libc_cv_cc_loop_to_function) +dnl GCC uses --help=warnings, Clang uses -print-diagnostic-options. +if ${CC-cc} --help=warnings 2>&1 | grep -q " -Wimplicit-fallthrough" \ + || ${CC-cc} -print-diagnostic-options 2>&1 | grep -q " -Wimplicit-fallthrough" +then + enable_wimplicit_fallthrough=yes +else + enable_wimplicit_fallthrough=no +fi +AC_SUBST(enable_wimplicit_fallthrough) + dnl Check whether we have the gd library available. AC_MSG_CHECKING(for libgd) if test "$with_gd" != "no"; then