On 4/12/21 5:02 PM, Nick Desaulniers wrote:
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
You can try the following patch to see whether it works or not.
diff --git a/tools/build/feature/test-reallocarray.c
b/tools/build/feature/test-reallocarray.c
index 8f6743e31da7..500cdeca07a7 100644
--- a/tools/build/feature/test-reallocarray.c
+++ b/tools/build/feature/test-reallocarray.c
@@ -1,5 +1,5 @@
// SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE
+#define _DEFAULT_SOURCE
#include <stdlib.h>
int main(void)
@@ -7,4 +7,4 @@ int main(void)
return !!reallocarray(NULL, 1, 1);
}
-#undef _GNU_SOURCE
+#undef _DEFAULT_SOURCE
[yhs@devbig003.ftw2 ~/work/bpf-next/tools/build]$
$ 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
