Add parse option to display points-to set information for pointer dereference

The points to set information provides some intuition about the complexity
of the resulting case split expression in case of a pointer dereference.
This commit adds parse option --show-points-to-sets to track the size and
contents of the points-to set for pointers.

cpp lint bmc_util.h

Add error message for plain and xml format output

Author: Natasha Yogananda Jeppu

src/cbmc/cbmc_parse_options.cpp

@@ -575,6 +575,17 @@ int cbmc_parse_optionst::doit()
     return CPROVER_EXIT_USAGE_ERROR;
   }
 
+  if(cmdline.isset("show-points-to-sets"))
+  {
+    if(!cmdline.isset("json-ui") || cmdline.isset("xml-ui"))
+    {
+      log.error() << "--show-points-to-sets supports only"
+                     " json output. Use --json-ui."
+                  << messaget::eom;
+      return CPROVER_EXIT_USAGE_ERROR;
+    }
+  }
+
   register_languages();
 
   // configure gcc, if required