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From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
To: ast@kernel.org, daniel@iogearbox.net, yhs@fb.com,
	davem@davemloft.net, jakub.kicinski@netronome.com,
	hawk@kernel.org, john.fastabend@gmail.com
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org, clang-built-linux@googlegroups.com,
	Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Subject: [PATCH bpf-next 10/11] libbpf: makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets
Date: Tue, 10 Sep 2019 13:38:29 +0300
Message-ID: <20190910103830.20794-11-ivan.khoronzhuk@linaro.org> (raw)
In-Reply-To: <20190910103830.20794-1-ivan.khoronzhuk@linaro.org>

In case of LDFLAGS and EXTRA_CC/CXX flags there is no way to pass them
correctly to build command, for instance when --sysroot is used or
external libraries are used, like -lelf, wich can be absent in
toolchain. This is used for samples/bpf cross-compiling allowing to
get elf lib from sysroot.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 samples/bpf/Makefile   |  8 +++++++-
 tools/lib/bpf/Makefile | 11 ++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 79c9aa41832e..4edc5232cfc1 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -186,6 +186,10 @@ ccflags-y += -I$(srctree)/tools/perf
 ccflags-y += $(D_OPTIONS)
 ccflags-y += -Wall
 ccflags-y += -fomit-frame-pointer
+
+EXTRA_CXXFLAGS := $(ccflags-y)
+
+# options not valid for C++
 ccflags-y += -Wmissing-prototypes
 ccflags-y += -Wstrict-prototypes
 
@@ -252,7 +256,9 @@ 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 $@) RM='rm -rf' EXTRA_CFLAGS="$(PROGS_CFLAGS)" \
+		EXTRA_CXXFLAGS="$(EXTRA_CXXFLAGS)" LDFLAGS=$(PROGS_LDFLAGS) \
+		srctree=$(BPF_SAMPLES_PATH)/../../ O=
 
 $(obj)/syscall_nrs.h:	$(obj)/syscall_nrs.s FORCE
 	$(call filechk,offsets,__SYSCALL_NRS_H__)
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index c6f94cffe06e..bccfa556ef4e 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -94,6 +94,10 @@ else
   CFLAGS := -g -Wall
 endif
 
+ifdef EXTRA_CXXFLAGS
+  CXXFLAGS := $(EXTRA_CXXFLAGS)
+endif
+
 ifeq ($(feature-libelf-mmap), 1)
   override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
 endif
@@ -176,8 +180,9 @@ $(BPF_IN): force elfdep bpfdep
 $(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
 
 $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN)
-	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
-				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
+	$(QUIET_LINK)$(CC) $(LDFLAGS) \
+		--shared -Wl,-soname,libbpf.so.$(LIBBPF_MAJOR_VERSION) \
+		-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
 	@ln -sf $(@F) $(OUTPUT)libbpf.so
 	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(LIBBPF_MAJOR_VERSION)
 
@@ -185,7 +190,7 @@ $(OUTPUT)libbpf.a: $(BPF_IN)
 	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
 
 $(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a
-	$(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@
+	$(QUIET_LINK)$(CXX) $(CXXFLAGS) $(LDFLAGS) $(INCLUDES) $^ -lelf -o $@
 
 $(OUTPUT)libbpf.pc:
 	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
-- 
2.17.1


  parent reply index

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10 10:38 [PATCH bpf-next 00/11] samples: bpf: improve/fix cross-compilation Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 01/11] samples: bpf: makefile: fix HDR_PROBE "echo" Ivan Khoronzhuk
2019-09-10 10:46   ` Sergei Shtylyov
2019-09-10 14:54     ` Ivan Khoronzhuk
2019-09-11 11:02       ` Sergei Shtylyov
2019-09-13 19:56         ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 02/11] samples: bpf: makefile: fix cookie_uid_helper_example obj build Ivan Khoronzhuk
2019-09-13 20:48   ` Yonghong Song
2019-09-13 21:25     ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 03/11] samples: bpf: makefile: use --target from cross-compile Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 04/11] samples: bpf: use own EXTRA_CFLAGS for clang commands Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 05/11] samples: bpf: makefile: use D vars from KBUILD_CFLAGS to handle headers Ivan Khoronzhuk
2019-09-13 21:12   ` Yonghong Song
2019-09-13 21:24     ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 06/11] samples: bpf: makefile: drop unnecessarily inclusion for bpf_load Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 07/11] samples: bpf: add makefile.prog for separate CC build Ivan Khoronzhuk
2019-09-13 21:33   ` Yonghong Song
2019-09-13 22:14     ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 08/11] samples: bpf: makefile: base progs build on makefile.progs Ivan Khoronzhuk
2019-09-13 21:41   ` Yonghong Song
2019-09-13 22:25     ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 09/11] samples: bpf: makefile: use CC environment for HDR_PROBE Ivan Khoronzhuk
2019-09-10 10:38 ` Ivan Khoronzhuk [this message]
2019-09-13 21:43   ` [PATCH bpf-next 10/11] libbpf: makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets Yonghong Song
2019-09-13 22:33     ` Ivan Khoronzhuk
2019-09-10 10:38 ` [PATCH bpf-next 11/11] samples: bpf: makefile: add sysroot support Ivan Khoronzhuk
2019-09-13 21:45   ` Yonghong Song
2019-09-13 22:36     ` Ivan Khoronzhuk

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