On Mon, Apr 12, 2021 at 4:58 PM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
>
> On Mon, Apr 12, 2021 at 7:29 AM Yonghong Song <yhs@xxxxxx> wrote:
> >
> > To build kernel with clang, people typically use
> > make -j60 LLVM=1 LLVM_IAS=1
> > LLVM_IAS=1 is not required for non-LTO build but
> > is required for LTO build. In my environment,
> > I am always having LLVM_IAS=1 regardless of
> > whether LTO is enabled or not.
> >
> > After kernel is build with clang, the following command
> > can be used to build selftests with clang:
> > make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
>
> Thank you for the series Yonghong. When I test the above command with
> your series applied, I observe:
> tools/include/tools/libc_compat.h:11:21: error: static declaration of
> 'reallocarray' follows non-static declaration
> static inline void *reallocarray(void *ptr, size_t nmemb, size_t size)
> ^
> /usr/include/stdlib.h:559:14: note: previous declaration is here
> extern void *reallocarray (void *__ptr, size_t __nmemb, size_t __size)
> ^
> so perhaps the detection of
> COMPAT_NEED_REALLOCARRAY/feature-reallocarray is incorrect?
Is this related to _DEFAULT_SOURCE vs _GNU_SOURCE. via man 3 reallocarray:
reallocarray():
Since glibc 2.29:
_DEFAULT_SOURCE
Glibc 2.28 and earlier:
_GNU_SOURCE
$ cd tools/testing/selftests/bpf
$ grep -rn _DEFAULT_SOURCE | wc -l
0
$ grep -rn _GNU_SOURCE | wc -l
37
$ ldd --version | head -n1
ldd (Debian GLIBC 2.31-9+build1) 2.31
--
Thanks,
~Nick Desaulniers
