From 8f7f8005f526c23d3e5537f5ab68c1c3fb422453 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@kernel.org>
Date: Mon, 30 Sep 2013 14:20:25 +0200
Subject: [PATCH] tools/perf/build: Split out feature check: 'libelf'

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-qznhihaasbysfqO7ffvRsf9q@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 tools/perf/config/Makefile                     | 4 ++--
 tools/perf/config/feature-checks/Makefile      | 4 ++++
 tools/perf/config/feature-checks/test-libelf.c | 7 +++++++
 3 files changed, 13 insertions(+), 2 deletions(-)
 create mode 100644 tools/perf/config/feature-checks/test-libelf.c

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index a2e0e1b200c3..68654281b973 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -108,6 +108,7 @@ FEATURE_TESTS =				\
 	volatile-register-var		\
 	fortify-source			\
 	bionic				\
+	libelf				\
 	libnuma
 
 $(foreach test,$(FEATURE_TESTS),$(call feature_check,$(test),$(test)))
@@ -164,8 +165,7 @@ ifdef NO_LIBELF
   NO_DEMANGLE := 1
   NO_LIBUNWIND := 1
 else
-  FLAGS_LIBELF=$(CFLAGS) $(LDFLAGS) $(EXTLIBS)
-  ifneq ($(call try-cc,$(SOURCE_LIBELF),$(FLAGS_LIBELF),libelf),y)
+  ifeq ($(feature-libelf), 0)
     FLAGS_GLIBC=$(CFLAGS) $(LDFLAGS)
     ifeq ($(call try-cc,$(SOURCE_GLIBC),$(FLAGS_GLIBC),glibc),y)
       LIBC_SUPPORT := 1
diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index 191df97a031d..789a38d21a34 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -6,6 +6,7 @@ FILES=					\
 	test-volatile-register-var	\
 	test-fortify-source		\
 	test-bionic			\
+	test-libelf			\
 	test-libnuma
 
 CC := $(CC) -MD
@@ -34,6 +35,9 @@ test-fortify-source:
 test-bionic:
 	$(BUILD)
 
+test-libelf:
+	$(BUILD) -lelf
+
 test-libnuma:
 	$(BUILD) -lnuma
 
diff --git a/tools/perf/config/feature-checks/test-libelf.c b/tools/perf/config/feature-checks/test-libelf.c
new file mode 100644
index 000000000000..1a08f9717344
--- /dev/null
+++ b/tools/perf/config/feature-checks/test-libelf.c
@@ -0,0 +1,7 @@
+#include <libelf.h>
+
+int main(void)
+{
+	Elf *elf = elf_begin(0, ELF_C_READ, 0);
+	return (long)elf;
+}
-- 
2.11.0