perf build: Don't unconditionally link the libbfd feature test to -liberty and -lz

Current libbfd feature test unconditionally links against -liberty and -lz.
While it's required on some systems (e.g. opensuse), it's completely
unnecessary on the others, where only -lbdf is sufficient (debian).
This patch streamlines (and renames) the following feature checks:

feature-libbfd           - only link against -lbfd (debian),
                           see commit 2cf9040714f3 ("perf tools: Fix bfd
			   dependency libraries detection")
feature-libbfd-liberty   - link against -lbfd and -liberty
feature-libbfd-liberty-z - link against -lbfd, -liberty and -lz (opensuse),
                           see commit 280e7c48c3b8 ("perf tools: fix BFD
			   detection on opensuse")

(feature-liberty{,-z} were renamed to feature-libbfd-liberty{,z}
for clarity)

The main motivation is to fix this feature test for bpftool which is
currently broken on debian (libbfd feature shows OFF, but we still
unconditionally link against -lbfd and it works).

Tested on debian with only -lbfd installed (without -liberty); I'd
appreciate if somebody on the other systems can test this new detection
method.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/4dfc634cfcfb236883971b5107cf3c28ec8a31be.1542328222.git.sdf@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 23 insertions, 21 deletions

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 07c1857c3d7a..b441c88cafa1 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -702,18 +702,20 @@ endif
 
 ifeq ($(feature-libbfd), 1)
   EXTLIBS += -lbfd
+else
+  # we are on a system that requires -liberty and (maybe) -lz
+  # to link against -lbfd; test each case individually here
 
   # call all detections now so we get correct
   # status in VF output
-  $(call feature_check,liberty)
-  $(call feature_check,liberty-z)
-  $(call feature_check,cplus-demangle)
+  $(call feature_check,libbfd-liberty)
+  $(call feature_check,libbfd-liberty-z)
 
-  ifeq ($(feature-liberty), 1)
-    EXTLIBS += -liberty
+  ifeq ($(feature-libbfd-liberty), 1)
+    EXTLIBS += -lbfd -liberty
   else
-    ifeq ($(feature-liberty-z), 1)
-      EXTLIBS += -liberty -lz
+    ifeq ($(feature-libbfd-liberty-z), 1)
+      EXTLIBS += -lbfd -liberty -lz
     endif
   endif
 endif
@@ -723,24 +725,24 @@ ifdef NO_DEMANGLE
 else
   ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
     EXTLIBS += -liberty
-    CFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT
   else
-    ifneq ($(feature-libbfd), 1)
-      ifneq ($(feature-liberty), 1)
-        ifneq ($(feature-liberty-z), 1)
-          # we dont have neither HAVE_CPLUS_DEMANGLE_SUPPORT
-          # or any of 'bfd iberty z' trinity
-          ifeq ($(feature-cplus-demangle), 1)
-            EXTLIBS += -liberty
-            CFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT
-          else
-            msg := $(warning No bfd.h/libbfd found, please install binutils-dev[el]/zlib-static/libiberty-dev to gain symbol demangling)
-            CFLAGS += -DNO_DEMANGLE
-          endif
-        endif
+    ifeq ($(filter -liberty,$(EXTLIBS)),)
+      $(call feature_check,cplus-demangle)
+
+      # we dont have neither HAVE_CPLUS_DEMANGLE_SUPPORT
+      # or any of 'bfd iberty z' trinity
+      ifeq ($(feature-cplus-demangle), 1)
+        EXTLIBS += -liberty
+      else
+        msg := $(warning No bfd.h/libbfd found, please install binutils-dev[el]/zlib-static/libiberty-dev to gain symbol demangling)
+        CFLAGS += -DNO_DEMANGLE
       endif
     endif
   endif
+
+  ifneq ($(filter -liberty,$(EXTLIBS)),)
+    CFLAGS += -DHAVE_CPLUS_DEMANGLE_SUPPORT
+  endif
 endif
 
 ifneq ($(filter -lbfd,$(EXTLIBS)),)