commit a4ecc9eb9b15bc51a1dc4726c06d35eaea74e162
Author: Joseph Myers <joseph@codesourcery.com>
Date: Wed Dec 10 01:14:48 2014 +0000
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 [$(enable-werror) = yes] (+gccwarn): Add -Werror
-Wno-error=undef.
(+gccwarn-c): Do not use -Werror=implicit-function-declaration.
* manual/install.texi (Configuring and compiling): Document
--disable-werror.
* INSTALL: Regenerated.
* debug/Makefile (CFLAGS-tst-chk1.c): Add -Wno-error.
(CFLAGS-tst-chk2.c): Likewise.
(CFLAGS-tst-chk3.c): Likewise.
(CFLAGS-tst-chk4.cc): Likewise.
(CFLAGS-tst-chk5.cc): Likewise.
(CFLAGS-tst-chk6.cc): Likewise.
(CFLAGS-tst-lfschk1.c): Likewise.
(CFLAGS-tst-lfschk2.c): Likewise.
(CFLAGS-tst-lfschk3.c): Likewise.
(CFLAGS-tst-lfschk4.cc): Likewise.
(CFLAGS-tst-lfschk5.cc): Likewise.
(CFLAGS-tst-lfschk6.cc): Likewise.
Conflicts:
INSTALL
manual/install.texi
(Textual conflicts due to elision backport;
glibc-rh841653-0.patch and others)
configure.ac
(Change applied to configure.in instead.)
diff --git a/INSTALL b/INSTALL
index 264e57bc5f0316f7..82b29f5d8746f929 100644
--- a/INSTALL
+++ b/INSTALL
@@ -143,6 +143,13 @@ will be used, and CFLAGS sets optimization options for the compiler.
`--enable-lock-elision=yes'
Enable lock elision for pthread mutexes by default.
+`--disable-werror'
+ By default, the GNU C Library is built with `-Werror'. If you wish
+ to build without this option (for example, if building with a newer
+ version of GCC than this version of the GNU C Library was tested
+ with, so new warnings cause the build with `-Werror' to fail), you
+ can configure with `--disable-werror'.
+
`--build=BUILD-SYSTEM'
`--host=HOST-SYSTEM'
These options are for cross-compiling. If you specify both
diff --git a/Makeconfig b/Makeconfig
index 02f1cc1255c5ac07..6f61e4835c0a7770 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -644,7 +644,10 @@ else
+gccwarn := -Wall -Wwrite-strings -Winline
endif
+gccwarn += -Wundef
-+gccwarn-c = -Wstrict-prototypes -Werror=implicit-function-declaration
+ifeq ($(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.
diff --git a/config.make.in b/config.make.in
index d5490f61cd3faeba..3c65c9f03ab65a74 100644
--- a/config.make.in
+++ b/config.make.in
@@ -49,6 +49,7 @@ 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@
diff --git a/configure b/configure
index b185b400dfbc21de..769f0fa149d0ef9c 100755
--- a/configure
+++ b/configure
@@ -660,6 +660,7 @@ build_pt_chown
build_nscd
link_obsolete_rpc
libc_cv_nss_crypt
+enable_werror
all_warnings
force_install
bindnow
@@ -758,6 +759,7 @@ enable_static_nss
enable_force_install
enable_kernel
enable_all_warnings
+enable_werror
enable_multi_arch
enable_nss_crypt
enable_obsolete_rpc
@@ -1419,6 +1421,7 @@ 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
@@ -3803,6 +3806,15 @@ 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
diff --git a/configure.in b/configure.in
index f8c36ba306e01f59..9feb463ddfed2a27 100644
--- a/configure.in
+++ b/configure.in
@@ -234,6 +234,13 @@ 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]),
diff --git a/debug/Makefile b/debug/Makefile
index e4efd9bcc687e562..6588b6327ae01205 100644
--- a/debug/Makefile
+++ b/debug/Makefile
@@ -89,19 +89,21 @@ CFLAGS-tst-longjmp_chk2.c = -fexceptions -fasynchronous-unwind-tables
CPPFLAGS-tst-longjmp_chk2.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++
diff --git a/manual/install.texi b/manual/install.texi
index 7fe6e005c3fdd5fb..3799cee621ddc4f9 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -177,6 +177,13 @@ you understand and accept those risks.
@item --enable-lock-elision=yes
Enable lock elision for pthread mutexes by default.
+@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