gcc-7.1.0gcc-7.1.0

1 files changed, 101 insertions, 43 deletions

diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index e94718834e..067d762c2a 100644
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -1,6 +1,6 @@
 /* Routines required for instrumenting a program.  */
 /* Compile this one with gcc.  */
-/* Copyright (C) 1989-2016 Free Software Foundation, Inc.
+/* Copyright (C) 1989-2017 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -26,6 +26,17 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "libgcov.h"
 #if !defined(inhibit_libc)
 
+/* Detect whether target can support atomic update of profilers.  */
+#if __SIZEOF_LONG_LONG__ == 4 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+#define GCOV_SUPPORTS_ATOMIC 1
+#else
+#if __SIZEOF_LONG_LONG__ == 8 && __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
+#define GCOV_SUPPORTS_ATOMIC 1
+#else
+#define GCOV_SUPPORTS_ATOMIC 0
+#endif
+#endif
+
 #ifdef L_gcov_interval_profiler
 /* If VALUE is in interval <START, START + STEPS - 1>, then increases the
    corresponding counter in COUNTERS.  If the VALUE is above or below
@@ -46,6 +57,26 @@ __gcov_interval_profiler (gcov_type *counters, gcov_type value,
 }
 #endif
 
+#if defined(L_gcov_interval_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
+/* If VALUE is in interval <START, START + STEPS - 1>, then increases the
+   corresponding counter in COUNTERS.  If the VALUE is above or below
+   the interval, COUNTERS[STEPS] or COUNTERS[STEPS + 1] is increased
+   instead.  Function is thread-safe.  */
+
+void
+__gcov_interval_profiler_atomic (gcov_type *counters, gcov_type value,
+				 int start, unsigned steps)
+{
+  gcov_type delta = value - start;
+  if (delta < 0)
+    __atomic_fetch_add (&counters[steps + 1], 1, __ATOMIC_RELAXED);
+  else if (delta >= steps)
+    __atomic_fetch_add (&counters[steps], 1, __ATOMIC_RELAXED);
+  else
+    __atomic_fetch_add (&counters[delta], 1, __ATOMIC_RELAXED);
+}
+#endif
+
 #ifdef L_gcov_pow2_profiler
 /* If VALUE is a power of two, COUNTERS[1] is incremented.  Otherwise
    COUNTERS[0] is incremented.  */
@@ -53,13 +84,28 @@ __gcov_interval_profiler (gcov_type *counters, gcov_type value,
 void
 __gcov_pow2_profiler (gcov_type *counters, gcov_type value)
 {
-  if (value & (value - 1))
+  if (value == 0 || (value & (value - 1)))
     counters[0]++;
   else
     counters[1]++;
 }
 #endif
 
+#if defined(L_gcov_pow2_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
+/* If VALUE is a power of two, COUNTERS[1] is incremented.  Otherwise
+   COUNTERS[0] is incremented.  Function is thread-safe.  */
+
+void
+__gcov_pow2_profiler_atomic (gcov_type *counters, gcov_type value)
+{
+  if (value == 0 || (value & (value - 1)))
+    __atomic_fetch_add (&counters[0], 1, __ATOMIC_RELAXED);
+  else
+    __atomic_fetch_add (&counters[1], 1, __ATOMIC_RELAXED);
+}
+#endif
+
+
 /* Tries to determine the most common value among its inputs.  Checks if the
    value stored in COUNTERS[0] matches VALUE.  If this is the case, COUNTERS[1]
    is incremented.  If this is not the case and COUNTERS[1] is not zero,
@@ -68,10 +114,12 @@ __gcov_pow2_profiler (gcov_type *counters, gcov_type value)
    function is called more than 50% of the time with one value, this value
    will be in COUNTERS[0] in the end.
 
-   In any case, COUNTERS[2] is incremented.  */
+   In any case, COUNTERS[2] is incremented.  If USE_ATOMIC is set to 1,
+   COUNTERS[2] is updated with an atomic instruction.  */
 
 static inline void
-__gcov_one_value_profiler_body (gcov_type *counters, gcov_type value)
+__gcov_one_value_profiler_body (gcov_type *counters, gcov_type value,
+				int use_atomic)
 {
   if (value == counters[0])
     counters[1]++;
@@ -82,14 +130,36 @@ __gcov_one_value_profiler_body (gcov_type *counters, gcov_type value)
     }
   else
     counters[1]--;
-  counters[2]++;
+
+  if (use_atomic)
+    __atomic_fetch_add (&counters[2], 1, __ATOMIC_RELAXED);
+  else
+    counters[2]++;
 }
 
 #ifdef L_gcov_one_value_profiler
 void
 __gcov_one_value_profiler (gcov_type *counters, gcov_type value)
 {
-  __gcov_one_value_profiler_body (counters, value);
+  __gcov_one_value_profiler_body (counters, value, 0);
+}
+#endif
+
+#if defined(L_gcov_one_value_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
+
+/* Update one value profilers (COUNTERS) for a given VALUE.
+
+   CAVEAT: Following function is not thread-safe, only total number
+   of executions (COUNTERS[2]) is update with an atomic instruction.
+   Problem is that one cannot atomically update two counters
+   (COUNTERS[0] and COUNTERS[1]), for more information please read
+   following email thread:
+   https://gcc.gnu.org/ml/gcc-patches/2016-08/msg00024.html.  */
+
+void
+__gcov_one_value_profiler_atomic (gcov_type *counters, gcov_type value)
+{
+  __gcov_one_value_profiler_body (counters, value, 1);
 }
 #endif
 
@@ -231,33 +301,6 @@ __gcov_indirect_call_topn_profiler (gcov_type value, void* cur_func)
 }
 #endif
 
-#ifdef L_gcov_indirect_call_profiler
-/* This function exist only for workaround of binutils bug 14342.
-   Once this compatibility hack is obsolette, it can be removed.  */
-
-/* By default, the C++ compiler will use function addresses in the
-   vtable entries.  Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero
-   tells the compiler to use function descriptors instead.  The value
-   of this macro says how many words wide the descriptor is (normally 2).
-
-   It is assumed that the address of a function descriptor may be treated
-   as a pointer to a function.  */
-
-/* Tries to determine the most common value among its inputs. */
-void
-__gcov_indirect_call_profiler (gcov_type* counter, gcov_type value,
-                               void* cur_func, void* callee_func)
-{
-  /* If the C++ virtual tables contain function descriptors then one
-     function may have multiple descriptors and we need to dereference
-     the descriptors to see if they point to the same function.  */
-  if (cur_func == callee_func
-      || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && callee_func
-          && *(void **) cur_func == *(void **) callee_func))
-    __gcov_one_value_profiler_body (counter, value);
-}
-#endif
-
 #ifdef L_gcov_indirect_call_profiler_v2
 
 /* These two variables are used to actually track caller and callee.  Keep
@@ -292,23 +335,15 @@ __gcov_indirect_call_profiler_v2 (gcov_type value, void* cur_func)
   if (cur_func == __gcov_indirect_call_callee
       || (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && __gcov_indirect_call_callee
           && *(void **) cur_func == *(void **) __gcov_indirect_call_callee))
-    __gcov_one_value_profiler_body (__gcov_indirect_call_counters, value);
+    __gcov_one_value_profiler_body (__gcov_indirect_call_counters, value, 0);
 }
 #endif
 
 #ifdef L_gcov_time_profiler
 
 /* Counter for first visit of each function.  */
-static gcov_type function_counter;
+gcov_type __gcov_time_profiler_counter ATTRIBUTE_HIDDEN;
 
-/* Sets corresponding COUNTERS if there is no value.  */
-
-void
-__gcov_time_profiler (gcov_type* counters)
-{
-  if (!counters[0])
-    counters[0] = ++function_counter;
-}
 #endif
 
 #ifdef L_gcov_average_profiler
@@ -323,6 +358,18 @@ __gcov_average_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
+#if defined(L_gcov_average_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
+/* Increase corresponding COUNTER by VALUE.  FIXME: Perhaps we want
+   to saturate up.  Function is thread-safe.  */
+
+void
+__gcov_average_profiler_atomic (gcov_type *counters, gcov_type value)
+{
+  __atomic_fetch_add (&counters[0], value, __ATOMIC_RELAXED);
+  __atomic_fetch_add (&counters[1], 1, __ATOMIC_RELAXED);
+}
+#endif
+
 #ifdef L_gcov_ior_profiler
 /* Bitwise-OR VALUE into COUNTER.  */
 
@@ -333,4 +380,15 @@ __gcov_ior_profiler (gcov_type *counters, gcov_type value)
 }
 #endif
 
+#if defined(L_gcov_ior_profiler_atomic) && GCOV_SUPPORTS_ATOMIC
+/* Bitwise-OR VALUE into COUNTER.  Function is thread-safe.  */
+
+void
+__gcov_ior_profiler_atomic (gcov_type *counters, gcov_type value)
+{
+  __atomic_fetch_or (&counters[0], value, __ATOMIC_RELAXED);
+}
+#endif
+
+
 #endif /* inhibit_libc */