Do not stream all zeros for gcda files.

gcc/ChangeLog:

	PR gcov-profile/95348
	* coverage.c (read_counts_file): Read only COUNTERS that are
	not all-zero.
	* gcov-dump.c (tag_function): Change signature from unsigned to
	signed integer.
	(tag_blocks): Likewise.
	(tag_arcs): Likewise.
	(tag_lines): Likewise.
	(tag_counters): Likewise.
	(tag_summary): Likewise.
	* gcov.c (read_count_file): Read all non-zero counters
	sensitively.

libgcc/ChangeLog:

	PR gcov-profile/95348
	* libgcov-driver.c (merge_one_data): Merge only profiles
	that are not of non-zero type.
	(write_one_data): Write counters only if there's one non-zero
	value.
	* libgcov-util.c (tag_function): Change signature from unsigned
	to int.
	(tag_blocks): Likewise.
	(tag_arcs): Likewise.
	(tag_counters): Likewise.
	(tag_summary): Likewise.
	(tag_lines): Read only if COUNTERS is non-zero.
	(read_gcda_file): Handle negative length for COUNTERS type.

3 files changed, 40 insertions, 29 deletions

diff --git a/gcc/coverage.c b/gcc/coverage.c
index 1dcda43..f353c9c 100644
--- a/gcc/coverage.c
+++ b/gcc/coverage.c
@@ -245,7 +245,9 @@ read_counts_file (void)
       else if (GCOV_TAG_IS_COUNTER (tag) && fn_ident)
 	{
 	  counts_entry **slot, *entry, elt;
-	  unsigned n_counts = GCOV_TAG_COUNTER_NUM (length);
+	  int read_length = (int)length;
+	  length = read_length > 0 ? read_length : 0;
+	  unsigned n_counts = GCOV_TAG_COUNTER_NUM (abs (read_length));
 	  unsigned ix;
 
 	  elt.ident = fn_ident;
@@ -274,8 +276,9 @@ read_counts_file (void)
 	      counts_hash = NULL;
 	      break;
 	    }
-	  for (ix = 0; ix != n_counts; ix++)
-	    entry->counts[ix] += gcov_read_counter ();
+	  if (read_length > 0)
+	    for (ix = 0; ix != n_counts; ix++)
+	      entry->counts[ix] = gcov_read_counter ();
 	}
       gcov_sync (offset, length);
       if ((is_error = gcov_is_error ()))
diff --git a/gcc/gcov-dump.c b/gcc/gcov-dump.c
index cfa771e4..97ff278 100644
--- a/gcc/gcov-dump.c
+++ b/gcc/gcov-dump.c
@@ -32,19 +32,19 @@ static void dump_gcov_file (const char *);
 static void print_prefix (const char *, unsigned, gcov_position_t);
 static void print_usage (void);
 static void print_version (void);
-static void tag_function (const char *, unsigned, unsigned, unsigned);
-static void tag_blocks (const char *, unsigned, unsigned, unsigned);
-static void tag_arcs (const char *, unsigned, unsigned, unsigned);
-static void tag_lines (const char *, unsigned, unsigned, unsigned);
-static void tag_counters (const char *, unsigned, unsigned, unsigned);
-static void tag_summary (const char *, unsigned, unsigned, unsigned);
+static void tag_function (const char *, unsigned, int, unsigned);
+static void tag_blocks (const char *, unsigned, int, unsigned);
+static void tag_arcs (const char *, unsigned, int, unsigned);
+static void tag_lines (const char *, unsigned, int, unsigned);
+static void tag_counters (const char *, unsigned, int, unsigned);
+static void tag_summary (const char *, unsigned, int, unsigned);
 extern int main (int, char **);
 
 typedef struct tag_format
 {
   unsigned tag;
   char const *name;
-  void (*proc) (const char *, unsigned, unsigned, unsigned);
+  void (*proc) (const char *, unsigned, int, unsigned);
 } tag_format_t;
 
 static int flag_dump_contents = 0;
@@ -225,6 +225,7 @@ dump_gcov_file (const char *filename)
   while (1)
     {
       gcov_position_t base, position = gcov_position ();
+      int read_length;
       unsigned tag, length;
       tag_format_t const *format;
       unsigned tag_depth;
@@ -234,7 +235,8 @@ dump_gcov_file (const char *filename)
       tag = gcov_read_unsigned ();
       if (!tag)
 	break;
-      length = gcov_read_unsigned ();
+      read_length = (int)gcov_read_unsigned ();
+      length = read_length > 0 ? read_length : 0;
       base = gcov_position ();
       mask = GCOV_TAG_MASK (tag) >> 1;
       for (tag_depth = 4; mask; mask >>= 8)
@@ -264,9 +266,9 @@ dump_gcov_file (const char *filename)
 	}
 
       print_prefix (filename, tag_depth, position);
-      printf ("%08x:%4u:%s", tag, length, format->name);
+      printf ("%08x:%4u:%s", tag, abs (read_length), format->name);
       if (format->proc)
-	(*format->proc) (filename, tag, length, depth);
+	(*format->proc) (filename, tag, read_length, depth);
 
       printf ("\n");
       if (flag_dump_contents && format->proc)
@@ -294,10 +296,10 @@ dump_gcov_file (const char *filename)
 
 static void
 tag_function (const char *filename ATTRIBUTE_UNUSED,
-	      unsigned tag ATTRIBUTE_UNUSED, unsigned length,
+	      unsigned tag ATTRIBUTE_UNUSED, int length,
 	      unsigned depth ATTRIBUTE_UNUSED)
 {
-  unsigned long pos = gcov_position ();
+  long pos = gcov_position ();
 
   if (!length)
     printf (" placeholder");
@@ -330,7 +332,7 @@ tag_function (const char *filename ATTRIBUTE_UNUSED,
 
 static void
 tag_blocks (const char *filename ATTRIBUTE_UNUSED,
-	    unsigned tag ATTRIBUTE_UNUSED, unsigned length ATTRIBUTE_UNUSED,
+	    unsigned tag ATTRIBUTE_UNUSED, int length ATTRIBUTE_UNUSED,
 	    unsigned depth ATTRIBUTE_UNUSED)
 {
   printf (" %u blocks", gcov_read_unsigned ());
@@ -338,7 +340,7 @@ tag_blocks (const char *filename ATTRIBUTE_UNUSED,
 
 static void
 tag_arcs (const char *filename ATTRIBUTE_UNUSED,
-	  unsigned tag ATTRIBUTE_UNUSED, unsigned length ATTRIBUTE_UNUSED,
+	  unsigned tag ATTRIBUTE_UNUSED, int length ATTRIBUTE_UNUSED,
 	  unsigned depth)
 {
   unsigned n_arcs = GCOV_TAG_ARCS_NUM (length);
@@ -380,7 +382,7 @@ tag_arcs (const char *filename ATTRIBUTE_UNUSED,
 
 static void
 tag_lines (const char *filename ATTRIBUTE_UNUSED,
-	   unsigned tag ATTRIBUTE_UNUSED, unsigned length ATTRIBUTE_UNUSED,
+	   unsigned tag ATTRIBUTE_UNUSED, int length ATTRIBUTE_UNUSED,
 	   unsigned depth)
 {
   if (flag_dump_contents)
@@ -425,7 +427,7 @@ tag_lines (const char *filename ATTRIBUTE_UNUSED,
 
 static void
 tag_counters (const char *filename ATTRIBUTE_UNUSED,
-	      unsigned tag ATTRIBUTE_UNUSED, unsigned length ATTRIBUTE_UNUSED,
+	      unsigned tag ATTRIBUTE_UNUSED, int length ATTRIBUTE_UNUSED,
 	      unsigned depth)
 {
 #define DEF_GCOV_COUNTER(COUNTER, NAME, MERGE_FN) NAME,
@@ -433,15 +435,16 @@ tag_counters (const char *filename ATTRIBUTE_UNUSED,
 #include "gcov-counter.def"
 };
 #undef DEF_GCOV_COUNTER
-  unsigned n_counts = GCOV_TAG_COUNTER_NUM (length);
+  int n_counts = GCOV_TAG_COUNTER_NUM (length);
+  bool has_zeros = n_counts < 0;
+  n_counts = abs (n_counts);
 
-  printf (" %s %u counts",
-	  counter_names[GCOV_COUNTER_FOR_TAG (tag)], n_counts);
+  printf (" %s %u counts%s",
+	  counter_names[GCOV_COUNTER_FOR_TAG (tag)], n_counts,
+	  has_zeros ? " (all zero)" : "");
   if (flag_dump_contents)
     {
-      unsigned ix;
-
-      for (ix = 0; ix != n_counts; ix++)
+      for (int ix = 0; ix != n_counts; ix++)
 	{
 	  gcov_type count;
 
@@ -457,7 +460,7 @@ tag_counters (const char *filename ATTRIBUTE_UNUSED,
 	      printf (VALUE_PADDING_PREFIX VALUE_PREFIX, ix);
 	    }
 
-	  count = gcov_read_counter ();
+	  count = has_zeros ? 0 : gcov_read_counter ();
 	  printf ("%" PRId64 " ", count);
 	}
     }
@@ -465,7 +468,7 @@ tag_counters (const char *filename ATTRIBUTE_UNUSED,
 
 static void
 tag_summary (const char *filename ATTRIBUTE_UNUSED,
-	     unsigned tag ATTRIBUTE_UNUSED, unsigned length ATTRIBUTE_UNUSED,
+	     unsigned tag ATTRIBUTE_UNUSED, int length ATTRIBUTE_UNUSED,
 	     unsigned depth ATTRIBUTE_UNUSED)
 {
   gcov_summary summary;
diff --git a/gcc/gcov.c b/gcc/gcov.c
index b2d2fda..b302e21 100644
--- a/gcc/gcov.c
+++ b/gcc/gcov.c
@@ -1972,11 +1972,16 @@ read_count_file (void)
 	}
       else if (tag == GCOV_TAG_FOR_COUNTER (GCOV_COUNTER_ARCS) && fn)
 	{
+	  int read_length = (int)length;
+	  length = abs (read_length);
 	  if (length != GCOV_TAG_COUNTER_LENGTH (fn->counts.size ()))
 	    goto mismatch;
 
-	  for (ix = 0; ix != fn->counts.size (); ix++)
-	    fn->counts[ix] += gcov_read_counter ();
+	  if (read_length > 0)
+	    for (ix = 0; ix != fn->counts.size (); ix++)
+	      fn->counts[ix] += gcov_read_counter ();
+	  else
+	    length = 0;
 	}
       gcov_sync (base, length);
       if ((error = gcov_is_error ()))