Handle a location with NULL as a file (PR driver/90495)

2019-05-17  Martin Liska  <mliska@suse.cz>

	PR driver/90495
	* toplev.c (output_stack_usage): With LTO and sanitizer it
	happens that a global ctor (_GLOBAL__sub_I_00099_0_main)
	has no file location.

From-SVN: r271312

gcc/ChangeLog

+2019-05-17  Martin Liska  <mliska@suse.cz>
+
+	PR driver/90495
+	* toplev.c (output_stack_usage): With LTO and sanitizer it
+	happens that a global ctor (_GLOBAL__sub_I_00099_0_main)
+	has no file location.
+
 2019-05-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/90484

gcc/toplev.c

@@ -1019,7 +1019,7 @@ output_stack_usage (void)
 
       fprintf (stack_usage_file,
 	       "%s:%d:%d:%s\t" HOST_WIDE_INT_PRINT_DEC"\t%s\n",
-	       lbasename (loc.file),
+	       loc.file == NULL ? "(artificial)" : lbasename (loc.file),
 	       loc.line,
 	       loc.column,
 	       name,