On 05/05/2024 22:56, John Hubbard wrote:
> When building either tools/bpf/bpftool, or tools/testing/selftests/hid,
> (the same Makefile is used for these), clang generates many instances of
> a warning that is useless here:
>
> "clang: warning: -lLLVM-17: 'linker' input unused"
>
> Silence this in both locations, by disabling that warning when building
> with clang.
>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
> ---
> tools/bpf/bpftool/Makefile | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index e9154ace80ff..c7457921d136 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -133,6 +133,10 @@ CFLAGS += -DUSE_LIBCAP
> LIBS += -lcap
> endif
>
> +ifneq ($(LLVM),)
> + CFLAGS += -Wno-unused-command-line-argument
> +endif
Thanks! If possible, I'd rather keep the warning enabled, and fix the
command line instead. Looking at the error and the Makefile, we may not
need the -lLLVM<version> in the CFLAGS at all, but only in $(LIBS). On
my setup, I can build successfully, without the warnings, with the
following patch:
------
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index b67454b45a49..dfa4f1bebbb3 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -147,7 +147,7 @@ ifeq ($(feature-llvm),1)
# If LLVM is available, use it for JIT disassembly
CFLAGS += -DHAVE_LLVM_SUPPORT
LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets
- CFLAGS += $(shell $(LLVM_CONFIG) --cflags --libs $(LLVM_CONFIG_LIB_COMPONENTS))
+ CFLAGS += $(shell $(LLVM_CONFIG) --cflags)
LIBS += $(shell $(LLVM_CONFIG) --libs $(LLVM_CONFIG_LIB_COMPONENTS))
ifeq ($(shell $(LLVM_CONFIG) --shared-mode),static)
LIBS += $(shell $(LLVM_CONFIG) --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
------
Could you please check whether that works on your side, too?
Quentin
