gcov: add support for GCC 4.9

This patch handles the gcov-related changes in GCC 4.9:

  A new counter (time profile) is added. The total number is 9 now.

  A new profile merge function __gcov_merge_time_profile is added.

See gcc/gcov-io.h and libgcc/libgcov-merge.c

For the first change, the layout of struct gcov_info is affected.

For the second one, a dummy function is added to kernel/gcov/base.c
similarly.

Signed-off-by: Yuan Pengfei <coolypf@qq.com>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 11 insertions, 0 deletions

diff --git a/kernel/gcov/base.c b/kernel/gcov/base.c
index f45b75b713c0..b358a802fd18 100644
--- a/kernel/gcov/base.c
+++ b/kernel/gcov/base.c
@@ -85,6 +85,12 @@ void __gcov_merge_ior(gcov_type *counters, unsigned int n_counters)
 }
 EXPORT_SYMBOL(__gcov_merge_ior);
 
+void __gcov_merge_time_profile(gcov_type *counters, unsigned int n_counters)
+{
+        /* Unused. */
+}
+EXPORT_SYMBOL(__gcov_merge_time_profile);
+
 /**
  * gcov_enable_events - enable event reporting through gcov_event()
  *
diff --git a/kernel/gcov/gcc_4_7.c b/kernel/gcov/gcc_4_7.c
index 2c6e4631c814..826ba9fb5e32 100644
--- a/kernel/gcov/gcc_4_7.c
+++ b/kernel/gcov/gcc_4_7.c
@@ -18,7 +18,12 @@
 #include <linux/vmalloc.h>
 #include "gcov.h"
 
+#if __GNUC__ == 4 && __GNUC_MINOR__ >= 9
+#define GCOV_COUNTERS                   9
+#else
 #define GCOV_COUNTERS                   8
+#endif
+
 #define GCOV_TAG_FUNCTION_LENGTH        3
 
 static struct gcov_info *gcov_info_head;