Smart relaxation of TOP N counter.

	PR tree-optimization/92924
	* profile.c (compute_value_histograms): Divide
	all counter values.
	PR tree-optimization/92924
	* libgcov-driver.c (prune_topn_counter): New.
	(prune_counters): Likewise.
	(dump_one_gcov): Prune a run-time counter.
	* libgcov-profiler.c (__gcov_topn_values_profiler_body):
	For a known value, add GCOV_TOPN_VALUES to value.
	Otherwise, decrement all counters by one.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d3a7bc25da898e8cde7bb8ef6bd66d921ce647b8..f672e939b5d994ee9df982d7d2f2651f562b7e85 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-22  Martin Liska  <mliska@suse.cz>
+
+       PR tree-optimization/92924
+       * profile.c (compute_value_histograms): Divide
+       all counter values.
+
 2020-01-22  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/91298

diff --git a/gcc/profile.c b/gcc/profile.c
index 6a2de21c3bd951c5b94235288b821a9bf8b9bf83..cd754c4c66a1f2ff4bcd7a8dd8ef2d9d70c04ff0 100644 (file)
--- a/gcc/profile.c
+++ b/gcc/profile.c
@@ -863,7 +863,15 @@ compute_value_histograms (histogram_values values, unsigned cfg_checksum,
 
       if (hist->type == HIST_TYPE_TOPN_VALUES
          || hist->type == HIST_TYPE_INDIR_CALL)
-       sort_hist_values (hist);
+       {
+         /* Each count value is multiplied by GCOV_TOPN_VALUES.  */
+         if (hist->hvalue.counters[2] != -1)
+           for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
+             hist->hvalue.counters[2 * i + 2]
+               = RDIV (hist->hvalue.counters[2 * i + 2], GCOV_TOPN_VALUES);
+
+         sort_hist_values (hist);
+       }
 
       /* Time profiler counter is not related to any statement,
          so that we have to read the counter and set the value to

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 5e8b506aabf269bc289fe29ecd7a35b11cb48d5d..441c8f0ccf17145de45f68e170200f26f8344722 100644 (file)
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,13 @@
+2020-01-22  Martin Liska  <mliska@suse.cz>
+
+       PR tree-optimization/92924
+       * libgcov-driver.c (prune_topn_counter): New.
+       (prune_counters): Likewise.
+       (dump_one_gcov): Prune a run-time counter.
+       * libgcov-profiler.c (__gcov_topn_values_profiler_body):
+       For a known value, add GCOV_TOPN_VALUES to value.
+       Otherwise, decrement all counters by one.
+
 2020-01-18  Hans-Peter Nilsson  <hp@axis.com>
 
        * config/cris/arit.c (DS): Apply attribute __fallthrough__.

diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c
index 1c07761b7f1d8f2200474625beb6d8af673b9b8f..cdb611de2a283bf1e21bec2cc5813902021b9032 100644 (file)
--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -213,6 +213,56 @@ static struct gcov_fn_buffer *fn_buffer;
 /* Including system dependent components. */
 #include "libgcov-driver-system.c"
 
+/* Prune TOP N value COUNTERS.  It's needed in order to preserve
+   reproducibility of builds.  */
+
+static void
+prune_topn_counter (gcov_type *counters, gcov_type all)
+{
+  if (counters[1] == -1)
+    return;
+
+  for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
+    {
+      if (counters[2 * i + 1] < all)
+       {
+         counters[2 * i] = 0;
+         counters[2 * i + 1] = 0;
+       }
+    }
+}
+
+/* Prune counters so that they are ready to store or merge.  */
+
+static void
+prune_counters (struct gcov_info *gi)
+{
+  for (unsigned i = 0; i < gi->n_functions; i++)
+    {
+      const struct gcov_fn_info *gfi = gi->functions[i];
+      const struct gcov_ctr_info *ci = gfi->ctrs;
+
+      for (unsigned j = 0; j < GCOV_COUNTERS; j++)
+       {
+         if (gi->merge[j] == NULL)
+           continue;
+
+         if (gi->merge[j] == __gcov_merge_topn)
+           {
+             gcc_assert (!(ci->num % GCOV_TOPN_VALUES_COUNTERS));
+             for (unsigned k = 0; k < (ci->num / GCOV_TOPN_VALUES_COUNTERS);
+                  k++)
+               {
+                 gcov_type *counters
+                   = ci->values + (k * GCOV_TOPN_VALUES_COUNTERS);
+                 prune_topn_counter (counters + 1, *counters);
+               }
+           }
+         ci++;
+       }
+    }
+}
+
 /* This function merges counters in GI_PTR to an existing gcda file.
    Return 0 on success.
    Return -1 on error. In this case, caller will goto read_fatal.  */
@@ -429,9 +479,11 @@ dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
   struct gcov_summary summary = {};
   int error;
   gcov_unsigned_t tag;
-
   fn_buffer = 0;
 
+  /* Prune current counters before we merge them.  */
+  prune_counters (gi_ptr);
+
   error = gcov_exit_open_gcda_file (gi_ptr, gf);
   if (error == -1)
     return;

diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index 9417904d462e7801f6cdffd4dea6896651531dfc..f45ef498a6e18790394ec88545cd3e691ddfc77b 100644 (file)
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -119,37 +119,35 @@ __gcov_topn_values_profiler_body (gcov_type *counters, gcov_type value,
 
   ++counters;
 
-  /* We have GCOV_TOPN_VALUES as we can keep multiple values
-     next to each other.  */
-  unsigned sindex = 0;
-
   for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
     {
       if (value == counters[2 * i])
        {
          if (use_atomic)
-           __atomic_fetch_add (&counters[2 * i + 1], 1, __ATOMIC_RELAXED);
+           __atomic_fetch_add (&counters[2 * i + 1], GCOV_TOPN_VALUES,
+                               __ATOMIC_RELAXED);
          else
-           counters[2 * i + 1]++;
+           counters[2 * i + 1] += GCOV_TOPN_VALUES;
          return;
        }
-      else if (counters[2 * i + 1] == 0)
+      else if (counters[2 * i + 1] <= 0)
        {
          /* We found an empty slot.  */
          counters[2 * i] = value;
-         counters[2 * i + 1] = 1;
+         counters[2 * i + 1] = GCOV_TOPN_VALUES;
          return;
        }
-
-      if (counters[2 * i + 1] < counters[2 * sindex + 1])
-       sindex = i;
     }
 
-  /* We haven't found an empty slot, then decrement the smallest.  */
-  if (use_atomic)
-    __atomic_fetch_sub (&counters[2 * sindex + 1], 1, __ATOMIC_RELAXED);
-  else
-    counters[2 * sindex + 1]--;
+  /* We haven't found an empty slot, then decrement all
+     counter values by one.  */
+  for (unsigned i = 0; i < GCOV_TOPN_VALUES; i++)
+    {
+      if (use_atomic)
+       __atomic_fetch_sub (&counters[2 * i + 1], 1, __ATOMIC_RELAXED);
+      else
+       counters[2 * i + 1]--;
+    }
 }
 
 #ifdef L_gcov_topn_values_profiler