From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Date: Fri, 11 Oct 2019 03:28:04 +0300
Subject: libbpf: Don't use cxx to test_libpf target
Patch-mainline: v5.5-rc1
Git-commit: 5c26f9a783581058c5de93627ae64139c4b32ceb
References: bsc#1177028

No need to use C++ for test_libbpf target when libbpf is on C and it
can be tested with C, after this change the CXXFLAGS in makefiles can
be avoided, at least in bpf samples, when sysroot is used, passing
same C/LDFLAGS as for lib.

Add "return 0" in test_libbpf to avoid warn, but also remove spaces at
start of the lines to keep same style and avoid warns while apply.

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20191011002808.28206-12-ivan.khoronzhuk@linaro.org
Acked-by: Gary Lin <glin@suse.com>
---
 tools/lib/bpf/Makefile        |   18 +++++-------------
 tools/lib/bpf/test_libbpf.c   |   20 ++++++++++++++++++++
 tools/lib/bpf/test_libbpf.cpp |   18 ------------------
 3 files changed, 25 insertions(+), 31 deletions(-)
 rename tools/lib/bpf/{test_libbpf.cpp => test_libbpf.c} (61%)

--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -52,7 +52,7 @@ ifndef VERBOSE
 endif
 
 FEATURE_USER = .libbpf
-FEATURE_TESTS = libelf libelf-mmap bpf reallocarray cxx
+FEATURE_TESTS = libelf libelf-mmap bpf reallocarray
 FEATURE_DISPLAY = libelf bpf
 
 INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
@@ -148,15 +148,7 @@ GLOBAL_SYM_COUNT = $(shell readelf -s --
 VERSIONED_SYM_COUNT = $(shell readelf -s --wide $(OUTPUT)libbpf.so | \
 			      grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l)
 
-CMD_TARGETS = $(LIB_TARGET) $(PC_FILE)
-
-CXX_TEST_TARGET = $(OUTPUT)test_libbpf
-
-ifeq ($(feature-cxx), 1)
-	CMD_TARGETS += $(CXX_TEST_TARGET)
-endif
-
-TARGETS = $(CMD_TARGETS)
+CMD_TARGETS = $(LIB_TARGET) $(PC_FILE) $(OUTPUT)test_libbpf
 
 all: fixdep
 	$(Q)$(MAKE) all_cmd
@@ -199,8 +191,8 @@ $(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(
 $(OUTPUT)libbpf.a: $(BPF_IN_STATIC)
 	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
 
-$(OUTPUT)test_libbpf: test_libbpf.cpp $(OUTPUT)libbpf.a
-	$(QUIET_LINK)$(CXX) $(INCLUDES) $^ -lelf -o $@
+$(OUTPUT)test_libbpf: test_libbpf.c $(OUTPUT)libbpf.a
+	$(QUIET_LINK)$(CC) $(INCLUDES) $^ -lelf -o $@
 
 $(OUTPUT)libbpf.pc:
 	$(QUIET_GEN)sed -e "s|@PREFIX@|$(prefix)|" \
@@ -275,7 +267,7 @@ config-clean:
 	$(Q)$(MAKE) -C $(srctree)/tools/build/feature/ clean >/dev/null
 
 clean:
-	$(call QUIET_CLEAN, libbpf) $(RM) -rf $(TARGETS) $(CXX_TEST_TARGET) \
+	$(call QUIET_CLEAN, libbpf) $(RM) $(CMD_TARGETS) \
 		*.o *~ *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) .*.d .*.cmd \
 		*.pc LIBBPF-CFLAGS bpf_helper_defs.h \
 		$(SHARED_OBJDIR) $(STATIC_OBJDIR)
--- /dev/null
+++ b/tools/lib/bpf/test_libbpf.c
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+#include "libbpf.h"
+#include "bpf.h"
+#include "btf.h"
+
+/* do nothing, just make sure we can link successfully */
+
+int main(int argc, char *argv[])
+{
+	/* libbpf.h */
+	libbpf_set_print(NULL);
+
+	/* bpf.h */
+	bpf_prog_get_fd_by_id(0);
+
+	/* btf.h */
+	btf__new(NULL, 0);
+
+	return 0;
+}
--- a/tools/lib/bpf/test_libbpf.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
-#include "libbpf.h"
-#include "bpf.h"
-#include "btf.h"
-
-/* do nothing, just make sure we can link successfully */
-
-int main(int argc, char *argv[])
-{
-    /* libbpf.h */
-    libbpf_set_print(NULL);
-
-    /* bpf.h */
-    bpf_prog_get_fd_by_id(0);
-
-    /* btf.h */
-    btf__new(NULL, 0);
-}