tools/perf/build: Split out feature check: 'dwarf'

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-dsx0fn9mjwfprizboANvtuup@git.kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

tools/perf/config/Makefile

@@ -110,6 +110,7 @@ FEATURE_TESTS =				\
 	bionic				\
 	libelf				\
 	glibc				\
+	dwarf				\
 	libnuma
 
 $(foreach test,$(FEATURE_TESTS),$(call feature_check,$(test),$(test)))
@@ -190,8 +191,7 @@ else
       LIBDW_LDFLAGS := -L$(LIBDW_DIR)/lib
     endif
 
-    FLAGS_DWARF=$(CFLAGS) $(LIBDW_CFLAGS) -ldw -lz -lelf $(LIBDW_LDFLAGS) $(LDFLAGS) $(EXTLIBS)
-    ifneq ($(call try-cc,$(SOURCE_DWARF),$(FLAGS_DWARF),libdw),y)
+    ifneq ($(feature-dwarf), 1)
       msg := $(warning No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev);
       NO_DWARF := 1
     endif # Dwarf support

tools/perf/config/feature-checks/Makefile

@@ -8,6 +8,7 @@ FILES=					\
 	test-bionic			\
 	test-libelf			\
 	test-glibc			\
+	test-dwarf			\
 	test-libnuma
 
 CC := $(CC) -MD
@@ -42,6 +43,9 @@ test-libelf:
 test-glibc:
 	$(BUILD)
 
+test-dwarf:
+	$(BUILD) -ldw
+
 test-libnuma:
 	$(BUILD) -lnuma
 

tools/perf/config/feature-checks/test-dwarf.c

+#include <dwarf.h>
+#include <elfutils/libdw.h>
+#include <elfutils/version.h>
+
+int main(void)
+{
+	Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
+	return (long)dbg;
+}