perf probe: Check if dwarf_getlocations() is available

If not, tell the user that:

  config/Makefile:273: Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157

And return -ENOTSUPP in die_get_var_range(), failing features that
need it, like the one pointed out above.

This fixes the build on older systems, such as Ubuntu 12.04.5.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Vinson Lee <vlee@freedesktop.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-9l7luqkq4gfnx7vrklkq4obs@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 6b7707270aa3b19791c8b6248f90ecddeabc1fdd..9f878619077aeb9ecbb50f87b381706d083def37 100644 (file)
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -30,6 +30,7 @@ endef
 FEATURE_TESTS_BASIC :=                 \
        backtrace                       \
        dwarf                           \
+       dwarf_getlocations              \
        fortify-source                  \
        sync-compare-and-swap           \
        glibc                           \
@@ -78,6 +79,7 @@ endif
 
 FEATURE_DISPLAY ?=                     \
        dwarf                           \
+       dwarf_getlocations              \
        glibc                           \
        gtk2                            \
        libaudit                        \

diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index c5f4c417428d7099fbe4f487a179b0663f478611..4ae94dbfdab98d5181e18d9d8864a24f942bdc53 100644 (file)
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -3,6 +3,7 @@ FILES=                                  \
        test-backtrace.bin              \
        test-bionic.bin                 \
        test-dwarf.bin                  \
+       test-dwarf_getlocations.bin     \
        test-fortify-source.bin         \
        test-sync-compare-and-swap.bin  \
        test-glibc.bin                  \
@@ -82,6 +83,9 @@ endif
 $(OUTPUT)test-dwarf.bin:
        $(BUILD) $(DWARFLIBS)
 
+$(OUTPUT)test-dwarf_getlocations.bin:
+       $(BUILD) $(DWARFLIBS)
+
 $(OUTPUT)test-libelf-mmap.bin:
        $(BUILD) -lelf
 

diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index e499a36c1e4a9e21e9c355309b53a7dc5901664a..a282e8cb84f308da358983ebccbf80c612e7d061 100644 (file)
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -41,6 +41,10 @@
 # include "test-dwarf.c"
 #undef main
 
+#define main main_test_dwarf_getlocations
+# include "test-dwarf_getlocations.c"
+#undef main
+
 #define main main_test_libelf_getphdrnum
 # include "test-libelf-getphdrnum.c"
 #undef main
@@ -143,6 +147,7 @@ int main(int argc, char *argv[])
        main_test_libelf_mmap();
        main_test_glibc();
        main_test_dwarf();
+       main_test_dwarf_getlocations();
        main_test_libelf_getphdrnum();
        main_test_libunwind();
        main_test_libaudit();

diff --git a/tools/build/feature/test-dwarf_getlocations.c b/tools/build/feature/test-dwarf_getlocations.c
new file mode 100644 (file)
index 0000000..7016269
--- /dev/null
+++ b/tools/build/feature/test-dwarf_getlocations.c
@@ -0,0 +1,12 @@
+#include <stdlib.h>
+#include <elfutils/libdw.h>
+
+int main(void)
+{
+       Dwarf_Addr base, start, end;
+       Dwarf_Attribute attr;
+       Dwarf_Op *op;
+        size_t nops;
+       ptrdiff_t offset = 0;
+        return (int)dwarf_getlocations(&attr, offset, &base, &start, &end, &op, &nops);
+}

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index f7d7f5a1cad538e44be9400b520ca32315eed999..6f8f6430f2bf6be5ef09565cabedf33ed8963a7b 100644 (file)
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -268,6 +268,12 @@ else
     ifneq ($(feature-dwarf), 1)
       msg := $(warning No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev);
       NO_DWARF := 1
+    else
+      ifneq ($(feature-dwarf_getlocations), 1)
+        msg := $(warning Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.157);
+      else
+        CFLAGS += -DHAVE_DWARF_GETLOCATIONS
+      endif # dwarf_getlocations
     endif # Dwarf support
   endif # libelf support
 endif # NO_LIBELF

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 577e600c8eb15a66cb50580b0c6361060147894a..aea189b41cc8c43f8ce325c4fde2f8ae27507df3 100644 (file)
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -959,6 +959,7 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
        return 0;
 }
 
+#ifdef HAVE_DWARF_GETLOCATIONS
 /**
  * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
  * @sp_die: a subprogram DIE
@@ -1080,3 +1081,11 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
 
        return ret;
 }
+#else
+int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
+                     Dwarf_Die *vr_die __maybe_unused,
+                     struct strbuf *buf __maybe_unused)
+{
+       return -ENOTSUP;
+}
+#endif