[RFC PATCH 8/9] perf: Add libunwind dependency for dwarf cfi unwinding

[Frederic Weisbecker <fweisbec@gmail.com>]

This is not mandatory, but required to get dwarf cfi unwinding
support.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
---
 tools/perf/Makefile          |   19 +++++++++++++++++++
 tools/perf/feature-tests.mak |   14 ++++++++++++++
 2 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 1146195..ca4cde1 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -515,6 +515,20 @@ ifneq ($(call try-cc,$(SOURCE_DWARF),$(FLAGS_DWARF)),y)
 endif # Dwarf support
 endif # NO_DWARF
 
+
+# Only x86-32 is supported for now
+ifneq ($(ARCH),x86)
+	NO_LIBUNWIND := 1
+endif
+
+ifndef NO_LIBUNWIND
+FLAGS_UNWIND=$(ALL_CFLAGS) -lunwind-x86 -lunwind-ptrace $(ALL_LDFLAGS) $(EXTLIBS)
+ifneq ($(call try-cc,$(SOURCE_LIBUNWIND),$(FLAGS_UNWIND)),y)
+	msg := $(warning No libunwind found. Please install libunwind >= 0.99);
+	NO_LIBUNWIND := 1
+endif # Libunwind support
+endif # NO_LIBUNWIND
+
 -include arch/$(ARCH)/Makefile
 
 ifeq ($(uname_S),Darwin)
@@ -561,6 +575,11 @@ else
 endif # PERF_HAVE_DWARF_REGS
 endif # NO_DWARF
 
+ifndef NO_LIBUNWIND
+	BASIC_CFLAGS += -DLIBUNWIND_SUPPORT
+	EXTLIBS += -lunwind-ptrace -lunwind-x86
+endif
+
 ifdef NO_NEWT
 	BASIC_CFLAGS += -DNO_NEWT_SUPPORT
 else
diff --git a/tools/perf/feature-tests.mak b/tools/perf/feature-tests.mak
index b253db6..367b213 100644
--- a/tools/perf/feature-tests.mak
+++ b/tools/perf/feature-tests.mak
@@ -90,6 +90,20 @@ int main(void)
 endef
 endif
 
+ifndef NO_LIBUNWIND
+define SOURCE_LIBUNWIND
+#include <libunwind.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+	addr_space = unw_create_addr_space(NULL, 0);
+	return 0;
+}
+endef
+endif
+
 define SOURCE_BFD
 #include <bfd.h>
 
-- 
1.6.2.3