Hi,
Le 23/11/2014 18:38, Lukasz Majewski a écrit :
Hi Albert,
Sorry for a late reply.
Hello Lukasz,
On Sat, 22 Nov 2014 07:56:35 +0100, Lukasz Majewski
<l.majew...@majess.pl> wrote:
Agreed in general, but not for this one, since "fixing" is the
carpet,
I assume that you are presenting below an answer to a "general"
case.
However, as Thomas pointed out earlier, this "fix" is perfectly safe
regarding the underlying kwbimage code.
Jeroen and I (full disclaimer: we have discussed the topic on IRC)
do not contend that the proposed fix would be unsafe; it *is* safe,
i.e. it does not adversely affect the code behavior in any measurable
way.
What we contend is that the fix be the /right/ fix (although Jeroen
and I have slightly differing criteria for defining what "the right
fix" would be).
and
the only justification I see as acceptable for doing so is when
leaving the warning enabled would cause an obnoxiously high
number of false positives.
Well let me add, if "fixing the warning" causes real error
to be hidden, we shouldn't "fix" the warnings by modifying
valid code.
Each subsequent "fix" for this kind of warning should be considered
case by case IMHO, therefore I agree with Albert.
Jeroen also agreed on IRC that disabling the compiler warning is not
the right fix either; and I agreed that there had to be a better fix
than pseudo-initializing headersz. I therefore suggested refactoring
kwbimage_set_header in order to ensure gcc does not emit the warning,
but without resorting to non-functional code such as a functionally
meaningless initialization.
Problem is, to refactor the code, one needs a gcc which emits the
warnig. I tried various versions of gcc (4.7.4, 4.8.3, 4.9.1) and all
remained silent when compiling tools/kwbimage.c.
Hence my request: Lukasz, which toolchain are you using exactly? Where
can we download it from?
The warning appear on my personal laptop too:
lukma@jawa:~/work/embedded/u-boot-denx (master)$ cc -v
Using built-in specs.
COLLECT_GCC=cc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.7.2-5'
--with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--enable-gnu-unique-object --enable-plugin --enable-objc-gc
--with-arch-32=i586 --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu Thread model: posix gcc version 4.7.2 (Debian
4.7.2-5)
HOSTCC tools/kwbimage.o
tools/kwbimage.c: In function ‘kwbimage_set_header’:
tools/kwbimage.c:803:8: warning: ‘headersz’ may be used uninitialized
in this function [-Wmaybe-uninitialized]
Debian distro: version 7.6 (Wheezy)
I also have this warning on my openSUSE 13.1 (GCC 4.8.1). If it could help, "gcc
-v" returns:
**********************************************************************
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/4.8/lto-wrapper
Target: x86_64-suse-linux
Configured with: ../configure --prefix=/usr --infodir=/usr/share/info
--mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64
--enable-languages=c,c++,objc,fortran,obj-c++,java,ada
--enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.8
--enable-ssp --disable-libssp --disable-plugin
--with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux'
--disable-libgcj --disable-libmudflap --with-slibdir=/lib64 --with-system-zlib
--enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch
--enable-version-specific-runtime-libs --enable-linker-build-id
--program-suffix=-4.8 --enable-linux-futex --without-system-libunwind
--with-arch-32=i586 --with-tune=generic --build=x86_64-suse-linux
Thread model: posix
gcc version 4.8.1 20130909 [gcc-4_8-branch revision 202388] (SUSE Linux)
**********************************************************************
Guillaume
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