Do not call strlen with NULL argument in libgcov.

2019-06-25  Martin Liska  <mliska@suse.cz>

	* libgcov-driver-system.c (replace_filename_variables): Do not
	call strlen with NULL argument.

From-SVN: r272650

libgcc/ChangeLog

+2019-06-25  Martin Liska  <mliska@suse.cz>
+
+	* libgcov-driver-system.c (replace_filename_variables): Do not
+	call strlen with NULL argument.
+
 2019-06-25  Andrew Stubbs  <ams@codesourcery.com>
 
 	* config/gcn/t-amdgcn (LIB2ADD): Add unwind-gcn.c.

libgcc/libgcov-driver-system.c

@@ -186,13 +186,14 @@ replace_filename_variables (char *filename)
 	  /* Concat beginning of the path, replacement and
 	     ending of the path.  */
 	  unsigned end = length - (p - filename);
-	  unsigned repl_length = strlen (replacement);
+	  unsigned repl_length = replacement != NULL ? strlen (replacement) : 0;
 
 	  char *buffer = (char *)xmalloc (start + end + repl_length + 1);
 	  char *buffer_ptr = buffer;
 	  buffer_ptr = (char *)memcpy (buffer_ptr, filename, start);
 	  buffer_ptr += start;
-	  buffer_ptr = (char *)memcpy (buffer_ptr, replacement, repl_length);
+	  if (replacement != NULL)
+	    buffer_ptr = (char *)memcpy (buffer_ptr, replacement, repl_length);
 	  buffer_ptr += repl_length;
 	  buffer_ptr = (char *)memcpy (buffer_ptr, p, end);
 	  buffer_ptr += end;