Re: clang: error: unknown argument '-static-libasan'; did you mean '-static-libsan'?

[Arnd Bergmann]

On Tue, Apr 16, 2024, at 16:33, Ryan Roberts wrote:
> On 16/04/2024 08:42, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>> head:   7efd0a74039fb6b584be2cb91c1d0ef0bd796ee1
>> commit: c652df8a4a9d7853fa1100b244024fd6f1a9c18a selftests: link libasan statically for tests with -fsanitize=address
>> compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
>> 
>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>> the same patch/commit), kindly add following tags
>> | Reported-by: kernel test robot <yujie.liu@xxxxxxxxx>
>> | Closes: https://lore.kernel.org/r/202404141807.LgsqXPY5-lkp@xxxxxxxxx/
>> 
>> All errors (new ones prefixed by >>):
>> 
>> # tools/testing/selftests/fchmodat2$ make CC=clang
>> clang -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan -isystem usr/include     fchmodat2_test.c  -o tools/testing/selftests/fchmodat2/fchmodat2_test
>> clang: error: unknown argument '-static-libasan'; did you mean '-static-libsan'?
>> make: *** [../lib.mk:181: tools/testing/selftests/fchmodat2/fchmodat2_test] Error 1
>> 
>> # tools/testing/selftests/openat2$ make CC=clang
>> clang -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan     openat2_test.c helpers.c helpers.h  -o tools/testing/selftests/openat2/openat2_test
>> clang: error: unknown argument '-static-libasan'; did you mean '-static-libsan'?
>> clang: error: cannot specify -o when generating multiple output files
>> make: *** [../lib.mk:181: tools/testing/selftests/openat2/openat2_test] Error 1
>> 
>
> Hi Arnd,
>
> This change went in quite a while ago and is on;y just blowing up. I saw your
> comment in another thread [1] that Andrew merged your change to set -Wextra.
> Perhaps that's what has caused this to show up only now? *although I don't
> actually see -Wextra in the command line).
>
> I guess the problem is that `-static-libasan` is only supported by gcc. But I'm
> Makefile-illiterate. Can anyone advise on what's the best way to make this
> argument gcc-only?

Thanks for letting me know about the problem, I had indeed missed
build-testing any of tools/testing, so this might not be
the only problem there.

I'm not entirely sure how much of the Kbuild infrastructure we
can rely on here. If the .config file gets included, this should
work:

--- a/tools/testing/selftests/fchmodat2/Makefile
+++ b/tools/testing/selftests/fchmodat2/Makefile
@@ -1,6 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined -static-libasan $(KHDR_INCLUDES)
+CFLAGS += -Wall -O2 -g -fsanitize=address -fsanitize=undefined $(KHDR_INCLUDES)
+ifdef CONFIG_CC_IS_GCC
+CFLAGS += -static-libasan
+else
+CFLAGS += -static-libsan
+endif
+
 TEST_GEN_PROGS := fchmodat2_test
 
 include ../lib.mk

Alternatively, if the cc-option macro is available, you could
try this one

CFLAGS += $(call cc-option, -static-libasan) $(call cc-option, -static-libsan) 

     Arnd