[gcc/devel/c++-coroutines] gcov: fix gcov-tool merge for TOPN counters

[Iain D Sandoe]

https://gcc.gnu.org/g:5fc312a98e9b06eac9e865f511a327b264056d66

commit 5fc312a98e9b06eac9e865f511a327b264056d66
Author: Martin Liska <mliska@suse.cz>
Date:   Tue Jun 16 14:14:03 2020 +0200

    gcov: fix gcov-tool merge for TOPN counters
    
    libgcc/ChangeLog:
    
            * libgcov-util.c (read_gcda_finalize): Remove const operator.
            (merge_wrapper): Add both counts and use them properly.
            (topn_to_memory_representation): New function.
            (gcov_merge): Covert on disk representation to in memory
            representation.
            * libgcov.h: Remove const operator.

Diff:
---
 libgcc/libgcov-util.c | 70 +++++++++++++++++++++++++++++++++++++++++++--------
 libgcc/libgcov.h      |  2 +-
 2 files changed, 61 insertions(+), 11 deletions(-)

diff --git a/libgcc/libgcov-util.c b/libgcc/libgcov-util.c
index fff54c6a3f6..224c190ee63 100644
--- a/libgcc/libgcov-util.c
+++ b/libgcc/libgcov-util.c
@@ -243,7 +243,7 @@ read_gcda_finalize (struct gcov_info *obj_info)
   /* We set the following fields: merge, n_functions, functions
      and summary.  */
   obj_info->n_functions = num_fn_info;
-  obj_info->functions = (const struct gcov_fn_info**) obstack_finish (&fn_info);
+  obj_info->functions = (struct gcov_fn_info**) obstack_finish (&fn_info);
 
   /* wrap all the counter array.  */
   for (i=0; i< GCOV_COUNTERS; i++)
@@ -506,14 +506,58 @@ gcov_get_merge_weight (void)
    value buffer and weights and then calls the merge function.  */
 
 static void
-merge_wrapper (gcov_merge_fn f, gcov_type *v1, gcov_unsigned_t n,
-               gcov_type *v2, unsigned w)
+merge_wrapper (gcov_merge_fn f, gcov_type *v1, gcov_unsigned_t n1,
+	       gcov_type *v2, gcov_unsigned_t n2, unsigned w)
 {
   gcov_value_buf = v2;
   gcov_value_buf_pos = 0;
-  gcov_value_buf_size = n;
+  gcov_value_buf_size = n2;
   gcov_merge_weight = w;
-  (*f) (v1, n);
+  (*f) (v1, n1);
+}
+
+/* Convert on disk representation of a TOPN counter to in memory representation
+   that is expected from __gcov_merge_topn function.  */
+
+static void
+topn_to_memory_representation (struct gcov_ctr_info *info)
+{
+  auto_vec<gcov_type> output;
+  gcov_type *values = info->values;
+  int count = info->num;
+
+  while (count > 0)
+    {
+      output.safe_push (values[0]);
+      gcov_type n = values[1];
+      output.safe_push (n);
+      if (n > 0)
+	{
+	  struct gcov_kvp *tuples
+	    = (struct gcov_kvp *)xcalloc (sizeof (struct gcov_kvp), n);
+	  for (unsigned i = 0; i < n - 1; i++)
+	    tuples[i].next = &tuples[i + 1];
+	  for (unsigned i = 0; i < n; i++)
+	    {
+	      tuples[i].value = values[2 + 2 * i];
+	      tuples[i].count = values[2 + 2 * i + 1];
+	    }
+	  output.safe_push ((intptr_t)&tuples[0]);
+	}
+      else
+	output.safe_push (0);
+
+      unsigned len = 2 * n + 2;
+      values += len;
+      count -= len;
+    }
+  gcc_assert (count == 0);
+
+  /* Allocate new buffer and copy it there.  */
+  info->num = output.length ();
+  info->values = (gcov_type *)xmalloc (sizeof (gcov_type) * info->num);
+  for (unsigned i = 0; i < info->num; i++)
+    info->values[i] = output[i];
 }
 
 /* Offline tool to manipulate profile data.
@@ -543,9 +587,9 @@ gcov_merge (struct gcov_info *info1, struct gcov_info *info2, int w)
   for (f_ix = 0; f_ix < n_functions; f_ix++)
     {
       unsigned t_ix;
-      const struct gcov_fn_info *gfi_ptr1 = info1->functions[f_ix];
-      const struct gcov_fn_info *gfi_ptr2 = info2->functions[f_ix];
-      const struct gcov_ctr_info *ci_ptr1, *ci_ptr2;
+      struct gcov_fn_info *gfi_ptr1 = info1->functions[f_ix];
+      struct gcov_fn_info *gfi_ptr2 = info2->functions[f_ix];
+      struct gcov_ctr_info *ci_ptr1, *ci_ptr2;
 
       if (!gfi_ptr1 || gfi_ptr1->key != info1)
         continue;
@@ -569,8 +613,14 @@ gcov_merge (struct gcov_info *info1, struct gcov_info *info2, int w)
           gcc_assert (merge1 == merge2);
           if (!merge1)
             continue;
-          gcc_assert (ci_ptr1->num == ci_ptr2->num);
-          merge_wrapper (merge1, ci_ptr1->values, ci_ptr1->num, ci_ptr2->values, w);
+
+	  if (merge1 == __gcov_merge_topn)
+	    topn_to_memory_representation (ci_ptr1);
+	  else
+	    gcc_assert (ci_ptr1->num == ci_ptr2->num);
+
+	  merge_wrapper (merge1, ci_ptr1->values, ci_ptr1->num,
+			 ci_ptr2->values, ci_ptr2->num, w);
           ci_ptr1++;
           ci_ptr2++;
         }
diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index 5d237a4c730..ffa9a690af4 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -216,7 +216,7 @@ struct gcov_info
   const struct gcov_fn_info *const *functions; /* pointer to pointers
                                                   to function information  */
 #else
-  const struct gcov_fn_info **functions;
+  struct gcov_fn_info **functions;
 #endif /* !IN_GCOV_TOOL */
 };