Expand @defined to support more cases

* tapsets.cxx (var_expanding_visitor::visit_defined_op): If no error was
  raised or replacement made on a target_symbol, then its @defined state
  is still indeterminate.  Some later pass (like @cast) might handle it.
* elaborate.cxx (const_folder::visit_defined_op): Squash any escapees.
* testsuite/semok/thirtysix.stp: Add more variants.

1 files changed, 15 insertions, 0 deletions

diff --git a/elaborate.cxx b/elaborate.cxx
index 5f3cc8ae..12dbce3a 100644
--- a/elaborate.cxx
+++ b/elaborate.cxx
@@ -3010,6 +3010,7 @@ struct const_folder: public update_visitor
   void visit_comparison (comparison* e);
   void visit_concatenation (concatenation* e);
   void visit_ternary_expression (ternary_expression* e);
+  void visit_defined_op (defined_op* e);
 };
 
 void
@@ -3471,6 +3472,20 @@ const_folder::visit_ternary_expression (ternary_expression* e)
     }
 }
 
+void
+const_folder::visit_defined_op (defined_op* e)
+{
+  // If a @defined makes it this far, then it is, de facto, undefined.
+
+  if (session.verbose>2)
+    clog << "Collapsing untouched @defined check " << *e->tok << endl;
+  relaxed_p = false;
+
+  literal_number* n = new literal_number (0);
+  n->tok = e->tok;
+  n->visit (this);
+}
+
 static void semantic_pass_const_fold (systemtap_session& s, bool& relaxed_p)
 {
   // Let's simplify statements with constant values.