2019-09-16 11:00:55

by Ivan Khoronzhuk

Subject: [PATCH v3 bpf-next 12/14] samples: bpf: makefile: provide C/CXX/LD flags to libbpf

In order to build libs using C/CXX/LD flags of target arch,
provide them to libbpf make.

Signed-off-by: Ivan Khoronzhuk <[email protected]>
---
samples/bpf/Makefile | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 18ec22e7b444..133123d4c7d7 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -182,8 +182,6 @@ ifdef CROSS_COMPILE
TPROGS_CFLAGS += -Wall
TPROGS_CFLAGS += -O2
TPROGS_CFLAGS += -fomit-frame-pointer
-TPROGS_CFLAGS += -Wmissing-prototypes
-TPROGS_CFLAGS += -Wstrict-prototypes
else
TPROGS_LDLIBS := $(KBUILD_HOSTLDLIBS)
TPROGS_CFLAGS += $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS)
@@ -196,6 +194,14 @@ TPROGS_CFLAGS += -I$(srctree)/tools/lib/
TPROGS_CFLAGS += -I$(srctree)/tools/include
TPROGS_CFLAGS += -I$(srctree)/tools/perf

+EXTRA_CXXFLAGS := $(TPROGS_CFLAGS)
+
+# options not valid for C++
+ifdef CROSS_COMPILE
+$(TPROGS_CFLAGS) += -Wmissing-prototypes
+$(TPROGS_CFLAGS) += -Wstrict-prototypes
+endif
+
TPROGCFLAGS_bpf_load.o += -Wno-unused-variable

TPROGS_LDLIBS += $(LIBBPF) -lelf
@@ -257,7 +263,9 @@ clean:

$(LIBBPF): FORCE
# Fix up variables inherited from Kbuild that tools/ build system won't like
- $(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
+ $(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
+ EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(TPROGS_LDFLAGS) \
+ srctree=$(BPF_SAMPLES_PATH)/../../ O=

$(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE
$(call filechk,offsets,__SYSCALL_NRS_H__)
--
2.17.1

2019-09-18 06:16:50

by Andrii Nakryiko

Subject: Re: [PATCH v3 bpf-next 12/14] samples: bpf: makefile: provide C/CXX/LD flags to libbpf

On Mon, Sep 16, 2019 at 3:58 AM Ivan Khoronzhuk
<[email protected]> wrote:
>
> In order to build libs using C/CXX/LD flags of target arch,
> provide them to libbpf make.
>
> Signed-off-by: Ivan Khoronzhuk <[email protected]>
> ---
> samples/bpf/Makefile | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 18ec22e7b444..133123d4c7d7 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -182,8 +182,6 @@ ifdef CROSS_COMPILE
> TPROGS_CFLAGS += -Wall
> TPROGS_CFLAGS += -O2
> TPROGS_CFLAGS += -fomit-frame-pointer
> -TPROGS_CFLAGS += -Wmissing-prototypes
> -TPROGS_CFLAGS += -Wstrict-prototypes
> else
> TPROGS_LDLIBS := $(KBUILD_HOSTLDLIBS)
> TPROGS_CFLAGS += $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS)
> @@ -196,6 +194,14 @@ TPROGS_CFLAGS += -I$(srctree)/tools/lib/
> TPROGS_CFLAGS += -I$(srctree)/tools/include
> TPROGS_CFLAGS += -I$(srctree)/tools/perf
>
> +EXTRA_CXXFLAGS := $(TPROGS_CFLAGS)
> +
> +# options not valid for C++
> +ifdef CROSS_COMPILE
> +$(TPROGS_CFLAGS) += -Wmissing-prototypes
> +$(TPROGS_CFLAGS) += -Wstrict-prototypes
> +endif
> +

ugh, let's really get rid of dependency on C++ compiler, as suggested
for previous patch.


> TPROGCFLAGS_bpf_load.o += -Wno-unused-variable
>
> TPROGS_LDLIBS += $(LIBBPF) -lelf
> @@ -257,7 +263,9 @@ clean:
>
> $(LIBBPF): FORCE
> # Fix up variables inherited from Kbuild that tools/ build system won't like
> - $(MAKE) -C $(dir $@) RM='rm -rf' LDFLAGS= srctree=$(BPF_SAMPLES_PATH)/../../ O=
> + $(MAKE) -C $(dir $@) RM='rm -rf' EXTRA_CFLAGS="$(TPROGS_CFLAGS)" \
> + EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(TPROGS_LDFLAGS) \
> + srctree=$(BPF_SAMPLES_PATH)/../../ O=
>
> $(obj)/syscall_nrs.h: $(obj)/syscall_nrs.s FORCE
> $(call filechk,offsets,__SYSCALL_NRS_H__)
> --
> 2.17.1
>