| Message ID | 20240505215636.63592-1-jhubbard@nvidia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | bpftool, selftests/hid/bpf: fix 29 clang warnings | expand |
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@nvidia.com> > --- > 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
On 5/5/24 3:36 PM, Quentin Monnet wrote: > On 05/05/2024 22:56, John Hubbard wrote: ... > 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? > Yes, that works, and of course that's much better. Please let me know if you prefer me to post a v2 with that, or if you plan on sending it yourself? thanks,
On 05/05/2024 23:48, John Hubbard wrote: > On 5/5/24 3:36 PM, Quentin Monnet wrote: >> On 05/05/2024 22:56, John Hubbard wrote: > ... >> 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 >> $(LLVM_CONFIG_LIB_COMPONENTS)) >> ------ >> >> Could you please check whether that works on your side, too? >> > > Yes, that works, and of course that's much better. Please let me > know if you prefer me to post a v2 with that, or if you plan > on sending it yourself? Please go ahead! Quentin
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index e9154ace80ff..c7457921d136 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -133,6 +133,10 @@ CFLAGS += -DUSE_LIBCAP LIBS += -lcap endif +ifneq ($(LLVM),) + CFLAGS += -Wno-unused-command-line-argument +endif + include $(wildcard $(OUTPUT)*.d) all: $(OUTPUT)bpftool
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@nvidia.com> --- tools/bpf/bpftool/Makefile | 4 ++++ 1 file changed, 4 insertions(+) base-commit: f462ae0edd3703edd6f22fe41d336369c38b884b prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27