[OE-core] [PATCH v3] gcc-sanitizers: fix -Werror=maybe-uninitialized issue

[Adrian Bunk]

On Mon, Apr 08, 2019 at 08:53:49PM -0700, Khem Raj wrote:
> On Mon, Apr 8, 2019 at 7:32 PM <mingli.yu at windriver.com> wrote:
> >
> > From: Mingli Yu <Mingli.Yu at windriver.com>
> >
> > When DEBUG_BUILD = "1" added in local.conf, there
> > comes below build error when "bitbake gcc-sanitizers":
> > | ./../../../../../../../../work-shared/gcc-8.3.0-r0/gcc-8.3.0/libsanitizer/libbacktrace/../../libbacktrace/elf.c: In function 'elf_is_symlink':
> > | ../../../../../../../../../work-shared/gcc-8.3.0-r0/gcc-8.3.0/libsanitizer/libbacktrace/../../libbacktrace/elf.c:772:21: error: 'st.st_mode' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> > |   return S_ISLNK (st.st_mode);
> >
> > Per https://gcc.gnu.org/ml/gcc-patches/2019-04/msg00315.html,
> > the gcc upstream thinks the warning is a false
> > positive and suggests to use -O2 rather than -Og
> > or -O1 when compiling that file, so pass -Wno-error
> > to compiler when -Og is used to silence the error.
> >
> 
> Not particular to this change but in general if a package says that it
> does not support -Og
> then we are just going to get into more and more untested grounds
> especially during runtime
> so I wonder how useful it will be to use -Og for such packages or any
> other non supported
> combination for that matter.

This has nothing to do with specific packages not supporting -Og
or any other combination, it is just about how to best workaround
a compiler bug temporarily.

gcc has bug(s) emitting bogus warnings with -Og, and these are build
failures with some packages that build with -Werror.

None of this is related to whether or not the packages will work
at runtime with -Og.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed