public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
* [gcc(refs/users/marxin/heads/PR98739-drop-profile-reproducibility-v3)] Restore profile reproducibility.
@ 2021-01-22 12:51 Martin Liska
  0 siblings, 0 replies; 3+ messages in thread
From: Martin Liska @ 2021-01-22 12:51 UTC (permalink / raw)
  To: gcc-cvs

https://gcc.gnu.org/g:aef618fd7c340e0ff9b1c5fc383e5bb2a301e9ba

commit aef618fd7c340e0ff9b1c5fc383e5bb2a301e9ba
Author: Martin Liska <mliska@suse.cz>
Date:   Fri Jan 22 11:27:16 2021 +0100

    Restore profile reproducibility.
    
    ChangeLog:
    
            PR gcov-profile/98739
            * Makefile.in: Add -fprofile-reproducible=parallel-runs for GCC
            bootstrap.
    
    gcc/ChangeLog:
    
            PR gcov-profile/98739
            * common.opt: Add missing sign symbol.
            * value-prof.c (get_nth_most_common_value): Restore handling
            of PROFILE_REPRODUCIBILITY_PARALLEL_RUNS and
            PROFILE_REPRODUCIBILITY_MULTITHREADED.
    
    libgcc/ChangeLog:
    
            PR gcov-profile/98739
            * libgcov-driver.c (prune_topn_counter): New.
            (prune_counters): New.
            (dump_one_gcov): Prune counters.
            * libgcov-merge.c (__gcov_merge_topn): Mark when merging
            ends with a dropped counter.
            * libgcov.h (gcov_topn_add_value): Add return value.

Diff:
---
 Makefile.in             |  2 +-
 gcc/common.opt          |  2 +-
 gcc/value-prof.c        | 14 +++++++-----
 libgcc/libgcov-driver.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++
 libgcc/libgcov-merge.c  | 11 ++++++---
 libgcc/libgcov.h        | 13 +++++++----
 6 files changed, 88 insertions(+), 14 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index 247cb9c8711..03785200dc7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -565,7 +565,7 @@ STAGEprofile_TFLAGS = $(STAGE2_TFLAGS)
 STAGEtrain_CFLAGS = $(filter-out -fchecking=1,$(STAGE3_CFLAGS))
 STAGEtrain_TFLAGS = $(filter-out -fchecking=1,$(STAGE3_TFLAGS))
 
-STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use
+STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use -fprofile-reproducible=parallel-runs
 STAGEfeedback_TFLAGS = $(STAGE4_TFLAGS)
 
 STAGEautoprofile_CFLAGS = $(STAGE2_CFLAGS) -g
diff --git a/gcc/common.opt b/gcc/common.opt
index bde1711870d..a8a2b67a99d 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2248,7 +2248,7 @@ Enum(profile_reproducibility) String(parallel-runs) Value(PROFILE_REPRODUCIBILIT
 EnumValue
 Enum(profile_reproducibility) String(multithreaded) Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
 
-fprofile-reproducible
+fprofile-reproducible=
 Common Joined RejectNegative Var(flag_profile_reproducible) Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
 -fprofile-reproducible=[serial|parallel-runs|multithreaded]	Control level of reproducibility of profile gathered by -fprofile-generate.
 
diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 4c916f4994f..8078a9569d7 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -747,8 +747,8 @@ gimple_divmod_fixed_value (gassign *stmt, tree value, profile_probability prob,
 
    abs (counters[0]) is the number of executions
    for i in 0 ... TOPN-1
-     counters[2 * i + 1] is target
-     abs (counters[2 * i + 2]) is corresponding hitrate counter.
+     counters[2 * i + 2] is target
+     counters[2 * i + 3] is corresponding hitrate counter.
 
    Value of counters[0] negative when counter became
    full during merging and some values are lost.  */
@@ -766,14 +766,18 @@ get_nth_most_common_value (gimple *stmt, const char *counter_type,
   *value = 0;
 
   gcov_type read_all = abs_hwi (hist->hvalue.counters[0]);
+  gcov_type covered = 0;
+  for (unsigned i = 0; i < counters; ++i)
+    covered += hist->hvalue.counters[2 * i + 3];
 
   gcov_type v = hist->hvalue.counters[2 * n + 2];
   gcov_type c = hist->hvalue.counters[2 * n + 3];
 
   if (hist->hvalue.counters[0] < 0
-      && (flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS
-	  || (flag_profile_reproducible
-	      == PROFILE_REPRODUCIBILITY_MULTITHREADED)))
+      && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS)
+    return false;
+  else if (covered != read_all
+	   && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_MULTITHREADED)
     return false;
 
   /* Indirect calls can't be verified.  */
diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c
index e474e032b54..55df1bafa79 100644
--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -213,6 +213,63 @@ 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 total = counters[0];
+  gcov_type threshold = total / GCOV_TOPN_MAXIMUM_TRACKED_VALUES;
+  gcov_type *nodes = &counters[1];
+
+  struct gcov_kvp **prev = (struct gcov_kvp **)(intptr_t)&counters[2];
+
+  for (struct gcov_kvp *node = *prev; node != NULL; node = node->next)
+    /* Count is small in this run, skip it.  */
+    {
+      if (node->count < threshold)
+	{
+	  --(*nodes);
+	  /* Skip the node from linked list.  */
+	  *prev = node->next;
+	}
+      else
+	prev = &node->next;
+    }
+}
+
+/* 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_MEM_COUNTERS));
+	      for (unsigned k = 0; k < (ci->num / GCOV_TOPN_MEM_COUNTERS); k++)
+		{
+		  gcov_type *counters
+		    = ci->values + (k * GCOV_TOPN_MEM_COUNTERS);
+		  prune_topn_counter (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.  */
@@ -475,6 +532,9 @@ dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
   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-merge.c b/libgcc/libgcov-merge.c
index 9306e8d688c..35936a8364b 100644
--- a/libgcc/libgcov-merge.c
+++ b/libgcc/libgcov-merge.c
@@ -107,7 +107,9 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
       gcov_type all = gcov_get_counter_ignore_scaling (-1);
       gcov_type n = gcov_get_counter_ignore_scaling (-1);
 
-      counters[GCOV_TOPN_MEM_COUNTERS * i] += all;
+      unsigned full = all < 0;
+      gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
+      *total += full ? -all : all;
 
       for (unsigned j = 0; j < n; j++)
 	{
@@ -115,9 +117,12 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 	  gcov_type count = gcov_get_counter_ignore_scaling (-1);
 
 	  // TODO: we should use atomic here
-	  gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i, value,
-			       count, 0, 0);
+	  full |= gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i,
+				       value, count, 0, 0);
 	}
+
+      if (full)
+	*total = -(*total);
     }
 }
 #endif /* L_gcov_merge_topn */
diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index b4a7e942a7e..df08e882dd7 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -435,9 +435,10 @@ allocate_gcov_kvp (void)
 
 /* Add key value pair VALUE:COUNT to a top N COUNTERS.  When INCREMENT_TOTAL
    is true, add COUNT to total of the TOP counter.  If USE_ATOMIC is true,
-   do it in atomic way.  */
+   do it in atomic way.  Return true when the counter is full, otherwise
+   return false.  */
 
-static inline void
+static inline unsigned
 gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 		     int use_atomic, int increment_total)
 {
@@ -453,7 +454,7 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (current_node->value == value)
 	{
 	  gcov_counter_add (&current_node->count, count, use_atomic);
-	  return;
+	  return 0;
 	}
 
       if (minimal_node == NULL
@@ -471,12 +472,14 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 	  minimal_node->value = value;
 	  minimal_node->count = count;
 	}
+
+      return 1;
     }
   else
     {
       struct gcov_kvp *new_node = allocate_gcov_kvp ();
       if (new_node == NULL)
-	return;
+	return 0;
 
       new_node->value = value;
       new_node->count = count;
@@ -515,6 +518,8 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (success)
 	gcov_counter_add (&counters[1], 1, use_atomic);
     }
+
+  return 0;
 }
 
 #endif /* !inhibit_libc */


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [gcc(refs/users/marxin/heads/PR98739-drop-profile-reproducibility-v3)] Restore profile reproducibility.
@ 2021-01-22 10:28 Martin Liska
  0 siblings, 0 replies; 3+ messages in thread
From: Martin Liska @ 2021-01-22 10:28 UTC (permalink / raw)
  To: gcc-cvs

https://gcc.gnu.org/g:3244a5ab4a5fd21c29657ea7e89b9ea400740111

commit 3244a5ab4a5fd21c29657ea7e89b9ea400740111
Author: Martin Liska <mliska@suse.cz>
Date:   Fri Jan 22 11:27:16 2021 +0100

    Restore profile reproducibility.

Diff:
---
 Makefile.in             |  2 +-
 gcc/common.opt          |  2 +-
 gcc/value-prof.c        | 14 +++++++-----
 libgcc/libgcov-driver.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++
 libgcc/libgcov-merge.c  | 11 ++++++---
 libgcc/libgcov.h        | 13 +++++++----
 6 files changed, 88 insertions(+), 14 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index 247cb9c8711..03785200dc7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -565,7 +565,7 @@ STAGEprofile_TFLAGS = $(STAGE2_TFLAGS)
 STAGEtrain_CFLAGS = $(filter-out -fchecking=1,$(STAGE3_CFLAGS))
 STAGEtrain_TFLAGS = $(filter-out -fchecking=1,$(STAGE3_TFLAGS))
 
-STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use
+STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use -fprofile-reproducible=parallel-runs
 STAGEfeedback_TFLAGS = $(STAGE4_TFLAGS)
 
 STAGEautoprofile_CFLAGS = $(STAGE2_CFLAGS) -g
diff --git a/gcc/common.opt b/gcc/common.opt
index bde1711870d..a8a2b67a99d 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2248,7 +2248,7 @@ Enum(profile_reproducibility) String(parallel-runs) Value(PROFILE_REPRODUCIBILIT
 EnumValue
 Enum(profile_reproducibility) String(multithreaded) Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
 
-fprofile-reproducible
+fprofile-reproducible=
 Common Joined RejectNegative Var(flag_profile_reproducible) Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
 -fprofile-reproducible=[serial|parallel-runs|multithreaded]	Control level of reproducibility of profile gathered by -fprofile-generate.
 
diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 4c916f4994f..8078a9569d7 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -747,8 +747,8 @@ gimple_divmod_fixed_value (gassign *stmt, tree value, profile_probability prob,
 
    abs (counters[0]) is the number of executions
    for i in 0 ... TOPN-1
-     counters[2 * i + 1] is target
-     abs (counters[2 * i + 2]) is corresponding hitrate counter.
+     counters[2 * i + 2] is target
+     counters[2 * i + 3] is corresponding hitrate counter.
 
    Value of counters[0] negative when counter became
    full during merging and some values are lost.  */
@@ -766,14 +766,18 @@ get_nth_most_common_value (gimple *stmt, const char *counter_type,
   *value = 0;
 
   gcov_type read_all = abs_hwi (hist->hvalue.counters[0]);
+  gcov_type covered = 0;
+  for (unsigned i = 0; i < counters; ++i)
+    covered += hist->hvalue.counters[2 * i + 3];
 
   gcov_type v = hist->hvalue.counters[2 * n + 2];
   gcov_type c = hist->hvalue.counters[2 * n + 3];
 
   if (hist->hvalue.counters[0] < 0
-      && (flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS
-	  || (flag_profile_reproducible
-	      == PROFILE_REPRODUCIBILITY_MULTITHREADED)))
+      && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS)
+    return false;
+  else if (covered != read_all
+	   && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_MULTITHREADED)
     return false;
 
   /* Indirect calls can't be verified.  */
diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c
index e474e032b54..55df1bafa79 100644
--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -213,6 +213,63 @@ 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 total = counters[0];
+  gcov_type threshold = total / GCOV_TOPN_MAXIMUM_TRACKED_VALUES;
+  gcov_type *nodes = &counters[1];
+
+  struct gcov_kvp **prev = (struct gcov_kvp **)(intptr_t)&counters[2];
+
+  for (struct gcov_kvp *node = *prev; node != NULL; node = node->next)
+    /* Count is small in this run, skip it.  */
+    {
+      if (node->count < threshold)
+	{
+	  --(*nodes);
+	  /* Skip the node from linked list.  */
+	  *prev = node->next;
+	}
+      else
+	prev = &node->next;
+    }
+}
+
+/* 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_MEM_COUNTERS));
+	      for (unsigned k = 0; k < (ci->num / GCOV_TOPN_MEM_COUNTERS); k++)
+		{
+		  gcov_type *counters
+		    = ci->values + (k * GCOV_TOPN_MEM_COUNTERS);
+		  prune_topn_counter (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.  */
@@ -475,6 +532,9 @@ dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
   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-merge.c b/libgcc/libgcov-merge.c
index 9306e8d688c..35936a8364b 100644
--- a/libgcc/libgcov-merge.c
+++ b/libgcc/libgcov-merge.c
@@ -107,7 +107,9 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
       gcov_type all = gcov_get_counter_ignore_scaling (-1);
       gcov_type n = gcov_get_counter_ignore_scaling (-1);
 
-      counters[GCOV_TOPN_MEM_COUNTERS * i] += all;
+      unsigned full = all < 0;
+      gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
+      *total += full ? -all : all;
 
       for (unsigned j = 0; j < n; j++)
 	{
@@ -115,9 +117,12 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 	  gcov_type count = gcov_get_counter_ignore_scaling (-1);
 
 	  // TODO: we should use atomic here
-	  gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i, value,
-			       count, 0, 0);
+	  full |= gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i,
+				       value, count, 0, 0);
 	}
+
+      if (full)
+	*total = -(*total);
     }
 }
 #endif /* L_gcov_merge_topn */
diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index b4a7e942a7e..df08e882dd7 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -435,9 +435,10 @@ allocate_gcov_kvp (void)
 
 /* Add key value pair VALUE:COUNT to a top N COUNTERS.  When INCREMENT_TOTAL
    is true, add COUNT to total of the TOP counter.  If USE_ATOMIC is true,
-   do it in atomic way.  */
+   do it in atomic way.  Return true when the counter is full, otherwise
+   return false.  */
 
-static inline void
+static inline unsigned
 gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 		     int use_atomic, int increment_total)
 {
@@ -453,7 +454,7 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (current_node->value == value)
 	{
 	  gcov_counter_add (&current_node->count, count, use_atomic);
-	  return;
+	  return 0;
 	}
 
       if (minimal_node == NULL
@@ -471,12 +472,14 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 	  minimal_node->value = value;
 	  minimal_node->count = count;
 	}
+
+      return 1;
     }
   else
     {
       struct gcov_kvp *new_node = allocate_gcov_kvp ();
       if (new_node == NULL)
-	return;
+	return 0;
 
       new_node->value = value;
       new_node->count = count;
@@ -515,6 +518,8 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (success)
 	gcov_counter_add (&counters[1], 1, use_atomic);
     }
+
+  return 0;
 }
 
 #endif /* !inhibit_libc */


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [gcc(refs/users/marxin/heads/PR98739-drop-profile-reproducibility-v3)] Restore profile reproducibility.
@ 2021-01-22 10:27 Martin Liska
  0 siblings, 0 replies; 3+ messages in thread
From: Martin Liska @ 2021-01-22 10:27 UTC (permalink / raw)
  To: gcc-cvs

https://gcc.gnu.org/g:99e34ef8c7490f63e1d812ed2e7d0211328683b9

commit 99e34ef8c7490f63e1d812ed2e7d0211328683b9
Author: Martin Liska <mliska@suse.cz>
Date:   Fri Jan 22 11:27:16 2021 +0100

    Restore profile reproducibility.

Diff:
---
 Makefile.in             |  2 +-
 gcc/common.opt          |  2 +-
 gcc/value-prof.c        | 14 +++++++-----
 libgcc/libgcov-driver.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++
 libgcc/libgcov-merge.c  | 11 ++++++---
 libgcc/libgcov.h        | 13 +++++++----
 6 files changed, 88 insertions(+), 14 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index 247cb9c8711..03785200dc7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -565,7 +565,7 @@ STAGEprofile_TFLAGS = $(STAGE2_TFLAGS)
 STAGEtrain_CFLAGS = $(filter-out -fchecking=1,$(STAGE3_CFLAGS))
 STAGEtrain_TFLAGS = $(filter-out -fchecking=1,$(STAGE3_TFLAGS))
 
-STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use
+STAGEfeedback_CFLAGS = $(STAGE4_CFLAGS) -fprofile-use -fprofile-reproducible=parallel-runs
 STAGEfeedback_TFLAGS = $(STAGE4_TFLAGS)
 
 STAGEautoprofile_CFLAGS = $(STAGE2_CFLAGS) -g
diff --git a/gcc/common.opt b/gcc/common.opt
index bde1711870d..a8a2b67a99d 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2248,7 +2248,7 @@ Enum(profile_reproducibility) String(parallel-runs) Value(PROFILE_REPRODUCIBILIT
 EnumValue
 Enum(profile_reproducibility) String(multithreaded) Value(PROFILE_REPRODUCIBILITY_MULTITHREADED)
 
-fprofile-reproducible
+fprofile-reproducible=
 Common Joined RejectNegative Var(flag_profile_reproducible) Enum(profile_reproducibility) Init(PROFILE_REPRODUCIBILITY_SERIAL)
 -fprofile-reproducible=[serial|parallel-runs|multithreaded]	Control level of reproducibility of profile gathered by -fprofile-generate.
 
diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 4c916f4994f..8078a9569d7 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -747,8 +747,8 @@ gimple_divmod_fixed_value (gassign *stmt, tree value, profile_probability prob,
 
    abs (counters[0]) is the number of executions
    for i in 0 ... TOPN-1
-     counters[2 * i + 1] is target
-     abs (counters[2 * i + 2]) is corresponding hitrate counter.
+     counters[2 * i + 2] is target
+     counters[2 * i + 3] is corresponding hitrate counter.
 
    Value of counters[0] negative when counter became
    full during merging and some values are lost.  */
@@ -766,14 +766,18 @@ get_nth_most_common_value (gimple *stmt, const char *counter_type,
   *value = 0;
 
   gcov_type read_all = abs_hwi (hist->hvalue.counters[0]);
+  gcov_type covered = 0;
+  for (unsigned i = 0; i < counters; ++i)
+    covered += hist->hvalue.counters[2 * i + 3];
 
   gcov_type v = hist->hvalue.counters[2 * n + 2];
   gcov_type c = hist->hvalue.counters[2 * n + 3];
 
   if (hist->hvalue.counters[0] < 0
-      && (flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS
-	  || (flag_profile_reproducible
-	      == PROFILE_REPRODUCIBILITY_MULTITHREADED)))
+      && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_PARALLEL_RUNS)
+    return false;
+  else if (covered != read_all
+	   && flag_profile_reproducible == PROFILE_REPRODUCIBILITY_MULTITHREADED)
     return false;
 
   /* Indirect calls can't be verified.  */
diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c
index e474e032b54..55df1bafa79 100644
--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -213,6 +213,63 @@ 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 total = counters[0];
+  gcov_type threshold = total / GCOV_TOPN_MAXIMUM_TRACKED_VALUES;
+  gcov_type *nodes = &counters[1];
+
+  struct gcov_kvp **prev = (struct gcov_kvp **)(intptr_t)&counters[2];
+
+  for (struct gcov_kvp *node = *prev; node != NULL; node = node->next)
+    /* Count is small in this run, skip it.  */
+    {
+      if (node->count < threshold)
+	{
+	  --(*nodes);
+	  /* Skip the node from linked list.  */
+	  *prev = node->next;
+	}
+      else
+	prev = &node->next;
+    }
+}
+
+/* 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_MEM_COUNTERS));
+	      for (unsigned k = 0; k < (ci->num / GCOV_TOPN_MEM_COUNTERS); k++)
+		{
+		  gcov_type *counters
+		    = ci->values + (k * GCOV_TOPN_MEM_COUNTERS);
+		  prune_topn_counter (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.  */
@@ -475,6 +532,9 @@ dump_one_gcov (struct gcov_info *gi_ptr, struct gcov_filename *gf,
   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-merge.c b/libgcc/libgcov-merge.c
index 9306e8d688c..35936a8364b 100644
--- a/libgcc/libgcov-merge.c
+++ b/libgcc/libgcov-merge.c
@@ -107,7 +107,9 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
       gcov_type all = gcov_get_counter_ignore_scaling (-1);
       gcov_type n = gcov_get_counter_ignore_scaling (-1);
 
-      counters[GCOV_TOPN_MEM_COUNTERS * i] += all;
+      unsigned full = all < 0;
+      gcov_type *total = &counters[GCOV_TOPN_MEM_COUNTERS * i];
+      *total += full ? -all : all;
 
       for (unsigned j = 0; j < n; j++)
 	{
@@ -115,9 +117,12 @@ __gcov_merge_topn (gcov_type *counters, unsigned n_counters)
 	  gcov_type count = gcov_get_counter_ignore_scaling (-1);
 
 	  // TODO: we should use atomic here
-	  gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i, value,
-			       count, 0, 0);
+	  full |= gcov_topn_add_value (counters + GCOV_TOPN_MEM_COUNTERS * i,
+				       value, count, 0, 0);
 	}
+
+      if (full)
+	*total = -(*total);
     }
 }
 #endif /* L_gcov_merge_topn */
diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index b4a7e942a7e..df08e882dd7 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -435,9 +435,10 @@ allocate_gcov_kvp (void)
 
 /* Add key value pair VALUE:COUNT to a top N COUNTERS.  When INCREMENT_TOTAL
    is true, add COUNT to total of the TOP counter.  If USE_ATOMIC is true,
-   do it in atomic way.  */
+   do it in atomic way.  Return true when the counter is full, otherwise
+   return false.  */
 
-static inline void
+static inline unsigned
 gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 		     int use_atomic, int increment_total)
 {
@@ -453,7 +454,7 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (current_node->value == value)
 	{
 	  gcov_counter_add (&current_node->count, count, use_atomic);
-	  return;
+	  return 0;
 	}
 
       if (minimal_node == NULL
@@ -471,12 +472,14 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 	  minimal_node->value = value;
 	  minimal_node->count = count;
 	}
+
+      return 1;
     }
   else
     {
       struct gcov_kvp *new_node = allocate_gcov_kvp ();
       if (new_node == NULL)
-	return;
+	return 0;
 
       new_node->value = value;
       new_node->count = count;
@@ -515,6 +518,8 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
       if (success)
 	gcov_counter_add (&counters[1], 1, use_atomic);
     }
+
+  return 0;
 }
 
 #endif /* !inhibit_libc */


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-01-22 12:51 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-22 12:51 [gcc(refs/users/marxin/heads/PR98739-drop-profile-reproducibility-v3)] Restore profile reproducibility Martin Liska
  -- strict thread matches above, loose matches on Subject: below --
2021-01-22 10:28 Martin Liska
2021-01-22 10:27 Martin Liska

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).