Use -Werror by default, add --disable-werror.

As discussed starting at
<https://sourceware.org/ml/libc-alpha/2014-11/msg00323.html>, this
patch makes the glibc build use -Werror by default to avoid
accidentally adding new warnings to the build.  The configure option
--disable-werror can be used to disable this.

-Wno-error=undef is temporarily used because the build isn't clean
regarding -Wundef warnings.  The idea is that once the remaining
-Wundef warnings have been cleaned up (in at least one configuration),
-Wno-error=undef will be removed.

I get a clean build and test on x86_64 (GCC 4.9 branch) with this
patch.  The expectation is that this may well break the build for some
other configurations, and people seeing such breakage should make
appropriate fixes to fix or suppress the warnings for their
configurations.  In some cases that may involve using pragmas as the
right fix (I think that will be right for the -Wno-inline issue for
MIPS I referred to in
<https://sourceware.org/ml/libc-alpha/2012-11/msg00798.html>, for
example), in some cases -Wno-error in sysdeps makefiles (__restore_rt
in MIPS sigaction, for example), in some cases substantive fixes for
the warnings.

Note that if, with a view to listing all the warnings then fixing them
all, you just look for "warning:" in output from building and testing
with --disable-werror, you'll see lots of warnings from the linker
about functions such as tmpnam.  Those warnings can be ignored - only
compiler warnings are relevant to -Werror, not linker warnings.

	* configure.ac (--disable-werror): New configure option.
	(enable_werror): New AC_SUBST.
	* configure: Regenerated.
	* config.make.in (enable-werror): New variable.
	* Makeconfig [$(enable-werror) = yes] (+gccwarn): Add -Werror
	-Wno-error=undef.
	(+gccwarn-c): Do not use -Werror=implicit-function-declaration.
	* manual/install.texi (Configuring and compiling): Document
	--disable-werror.
	* INSTALL: Regenerated.
	* debug/Makefile (CFLAGS-tst-chk1.c): Add -Wno-error.
	(CFLAGS-tst-chk2.c): Likewise.
	(CFLAGS-tst-chk3.c): Likewise.
	(CFLAGS-tst-chk4.cc): Likewise.
	(CFLAGS-tst-chk5.cc): Likewise.
	(CFLAGS-tst-chk6.cc): Likewise.
	(CFLAGS-tst-lfschk1.c): Likewise.
	(CFLAGS-tst-lfschk2.c): Likewise.
	(CFLAGS-tst-lfschk3.c): Likewise.
	(CFLAGS-tst-lfschk4.cc): Likewise.
	(CFLAGS-tst-lfschk5.cc): Likewise.
	(CFLAGS-tst-lfschk6.cc): Likewise.
This commit is contained in:
Joseph Myers 2014-12-10 01:14:48 +00:00
parent 0f88636c09
commit a4ecc9eb9b
9 changed files with 79 additions and 14 deletions

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@ -1,5 +1,28 @@
2014-12-10 Joseph Myers <joseph@codesourcery.com>
* configure.ac (--disable-werror): New configure option.
(enable_werror): New AC_SUBST.
* configure: Regenerated.
* config.make.in (enable-werror): New variable.
* Makeconfig [$(enable-werror) = yes] (+gccwarn): Add -Werror
-Wno-error=undef.
(+gccwarn-c): Do not use -Werror=implicit-function-declaration.
* manual/install.texi (Configuring and compiling): Document
--disable-werror.
* INSTALL: Regenerated.
* debug/Makefile (CFLAGS-tst-chk1.c): Add -Wno-error.
(CFLAGS-tst-chk2.c): Likewise.
(CFLAGS-tst-chk3.c): Likewise.
(CFLAGS-tst-chk4.cc): Likewise.
(CFLAGS-tst-chk5.cc): Likewise.
(CFLAGS-tst-chk6.cc): Likewise.
(CFLAGS-tst-lfschk1.c): Likewise.
(CFLAGS-tst-lfschk2.c): Likewise.
(CFLAGS-tst-lfschk3.c): Likewise.
(CFLAGS-tst-lfschk4.cc): Likewise.
(CFLAGS-tst-lfschk5.cc): Likewise.
(CFLAGS-tst-lfschk6.cc): Likewise.
* stdio-common/tst-printfsz.c: Include <libc-internal.h>.
(main): Disable -Wdeprecated-declarations around calls to
register_printf_function.

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@ -143,6 +143,13 @@ will be used, and CFLAGS sets optimization options for the compiler.
additional security risks to the system and you should enable it
only if you understand and accept those risks.
`--disable-werror'
By default, the GNU C Library is built with `-Werror'. If you wish
to build without this option (for example, if building with a newer
version of GCC than this version of the GNU C Library was tested
with, so new warnings cause the build with `-Werror' to fail), you
can configure with `--disable-werror'.
`--build=BUILD-SYSTEM'
`--host=HOST-SYSTEM'
These options are for cross-compiling. If you specify both

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@ -717,7 +717,10 @@ else
+gccwarn := -Wall -Wwrite-strings -Winline
endif
+gccwarn += -Wundef
+gccwarn-c = -Wstrict-prototypes -Werror=implicit-function-declaration
ifeq ($(enable-werror),yes)
+gccwarn += -Werror -Wno-error=undef
endif
+gccwarn-c = -Wstrict-prototypes
# We do not depend on the address of constants in different files to be
# actually different, so allow the compiler to merge them all.

3
NEWS
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@ -26,6 +26,9 @@ Version 2.21
C Library is GCC 4.6. Older GCC versions, and non-GNU compilers, can
still be used to compile programs using the GNU C Library.
* The GNU C Library is now built with -Werror by default. This can be
disabled by configuring with --disable-werror.
* New locales: tu_IN, bh_IN, raj_IN, ce_RU.
* The obsolete sigvec function has been removed. This was the original

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@ -45,6 +45,7 @@ sysheaders = @sysheaders@
sysincludes = @SYSINCLUDES@
c++-sysincludes = @CXX_SYSINCLUDES@
all-warnings = @all_warnings@
enable-werror = @enable_werror@
have-z-combreloc = @libc_cv_z_combreloc@
have-z-execstack = @libc_cv_z_execstack@

12
configure vendored
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@ -668,6 +668,7 @@ build_pt_chown
build_nscd
link_obsolete_rpc
libc_cv_nss_crypt
enable_werror
all_warnings
force_install
bindnow
@ -767,6 +768,7 @@ enable_force_install
enable_maintainer_mode
enable_kernel
enable_all_warnings
enable_werror
enable_multi_arch
enable_nss_crypt
enable_obsolete_rpc
@ -1428,6 +1430,7 @@ Optional Features:
--enable-kernel=VERSION compile for compatibility with kernel not older than
VERSION
--enable-all-warnings enable all useful warnings gcc can issue
--disable-werror do not build with -Werror
--enable-multi-arch enable single DSO with optimizations for multiple
architectures
--enable-nss-crypt enable libcrypt to use nss
@ -3565,6 +3568,15 @@ fi
# Check whether --enable-werror was given.
if test "${enable_werror+set}" = set; then :
enableval=$enable_werror; enable_werror=$enableval
else
enable_werror=yes
fi
# Check whether --enable-multi-arch was given.
if test "${enable_multi_arch+set}" = set; then :
enableval=$enable_multi_arch; multi_arch=$enableval

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@ -253,6 +253,13 @@ AC_ARG_ENABLE([all-warnings],
[])
AC_SUBST(all_warnings)
AC_ARG_ENABLE([werror],
AC_HELP_STRING([--disable-werror],
[do not build with -Werror]),
[enable_werror=$enableval],
[enable_werror=yes])
AC_SUBST(enable_werror)
AC_ARG_ENABLE([multi-arch],
AC_HELP_STRING([--enable-multi-arch],
[enable single DSO with optimizations for multiple architectures]),

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@ -96,19 +96,21 @@ CFLAGS-tst-longjmp_chk3.c = -fexceptions -fasynchronous-unwind-tables
CPPFLAGS-tst-longjmp_chk3.c = -D_FORTIFY_SOURCE=1
# We know these tests have problems with format strings, this is what
# we are testing. Disable that warning.
CFLAGS-tst-chk1.c = -Wno-format
CFLAGS-tst-chk2.c = -Wno-format
CFLAGS-tst-chk3.c = -Wno-format
CFLAGS-tst-chk4.cc = -Wno-format
CFLAGS-tst-chk5.cc = -Wno-format
CFLAGS-tst-chk6.cc = -Wno-format
CFLAGS-tst-lfschk1.c = -Wno-format
CFLAGS-tst-lfschk2.c = -Wno-format
CFLAGS-tst-lfschk3.c = -Wno-format
CFLAGS-tst-lfschk4.cc = -Wno-format
CFLAGS-tst-lfschk5.cc = -Wno-format
CFLAGS-tst-lfschk6.cc = -Wno-format
# we are testing. Disable that warning. They also generate warnings
# from warning attributes, which cannot be disabled via pragmas, so
# require -Wno-error to be used.
CFLAGS-tst-chk1.c = -Wno-format -Wno-error
CFLAGS-tst-chk2.c = -Wno-format -Wno-error
CFLAGS-tst-chk3.c = -Wno-format -Wno-error
CFLAGS-tst-chk4.cc = -Wno-format -Wno-error
CFLAGS-tst-chk5.cc = -Wno-format -Wno-error
CFLAGS-tst-chk6.cc = -Wno-format -Wno-error
CFLAGS-tst-lfschk1.c = -Wno-format -Wno-error
CFLAGS-tst-lfschk2.c = -Wno-format -Wno-error
CFLAGS-tst-lfschk3.c = -Wno-format -Wno-error
CFLAGS-tst-lfschk4.cc = -Wno-format -Wno-error
CFLAGS-tst-lfschk5.cc = -Wno-format -Wno-error
CFLAGS-tst-lfschk6.cc = -Wno-format -Wno-error
LDLIBS-tst-chk4 = -lstdc++
LDLIBS-tst-chk5 = -lstdc++
LDLIBS-tst-chk6 = -lstdc++

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@ -174,6 +174,13 @@ setuid and owned by @code{root}. The use of @file{pt_chown} introduces
additional security risks to the system and you should enable it only if
you understand and accept those risks.
@item --disable-werror
By default, @theglibc{} is built with @option{-Werror}. If you wish
to build without this option (for example, if building with a newer
version of GCC than this version of @theglibc{} was tested with, so
new warnings cause the build with @option{-Werror} to fail), you can
configure with @option{--disable-werror}.
@item --build=@var{build-system}
@itemx --host=@var{host-system}
These options are for cross-compiling. If you specify both options and