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From:   Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
To:     linux@armlinux.org.uk, 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-arm-kernel@lists.infradead.org, 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 RFC bpf-next 03/10] libbpf: Makefile: add C/CXX/LDFLAGS to libbpf.so and test_libpf targets
Date:   Fri, 30 Aug 2019 03:50:30 +0300
Message-Id: <20190830005037.24004-4-ivan.khoronzhuk@linaro.org>
In-Reply-To: <20190830005037.24004-1-ivan.khoronzhuk@linaro.org>
References: <20190830005037.24004-1-ivan.khoronzhuk@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In case of LDFLAGS and EXTRA_CC 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. In follow patches this is
used for samples/bpf cross-compiling.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 tools/lib/bpf/Makefile | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 844f6cd79c03..d606d249e334 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -99,6 +99,10 @@ else
   CFLAGS := -g -Wall
 endif
 
+ifdef EXTRA_CXXFLAGS
+  CXXFLAGS := $(EXTRA_CXXFLAGS)
+endif
+
 ifeq ($(feature-libelf-mmap), 1)
   override CFLAGS += -DHAVE_LIBELF_MMAP_SUPPORT
 endif
@@ -179,8 +183,9 @@ $(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.$(VERSION) \
-				    -Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
+	$(QUIET_LINK)$(CC) $(LDFLAGS) \
+		--shared -Wl,-soname,libbpf.so.$(VERSION) \
+		-Wl,--version-script=$(VERSION_SCRIPT) $^ -lelf -o $@
 	@ln -sf $(@F) $(OUTPUT)libbpf.so
 	@ln -sf $(@F) $(OUTPUT)libbpf.so.$(VERSION)
 
@@ -188,7 +193,7 @@ $(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