PR11005: @defined($tvar) predicate, part 1

* staptree.h (defined_op): New class.
* all files: Extend all visitors as appropriate, mostly
  dummy/pass-through implementation.
* parse.cxx (parse_target_symbol): New function, factored out
  of parse_symbol().
  (parse_define_op): New function.
* NEWS: Mention it.
* parse.h: Corresponding changes.
* tapsets.cxx (var_expanding_visitor::visit_defined_op):
  Implement @defined() semantics.
  (dwarf_var_expanding_visitor::visit_target_symbol): Adjust.
* tapset-utrace.c (visit_target_symbol_arg): Avoid crashes
  on $argZZZ.
* tapsets.cxx (sdt_var_expanding_visitor): Ditto.
* semok/thirtysix.stp: New test.

1 files changed, 3 insertions, 1 deletions

diff --git a/tapsets.h b/tapsets.h
index 115f2ccf..bdaf3201 100644
--- a/tapsets.h
+++ b/tapsets.h
@@ -1,5 +1,5 @@
 // -*- C++ -*-
-// Copyright (C) 2005, 2009 Red Hat Inc.
+// Copyright (C) 2005-2010 Red Hat Inc.
 //
 // This file is part of systemtap, and is free software.  You can
 // redistribute it and/or modify it under the terms of the GNU General
@@ -49,9 +49,11 @@ struct var_expanding_visitor: public update_visitor
 {
   static unsigned tick;
   std::stack<functioncall**> target_symbol_setter_functioncalls;
+  std::stack<defined_op*> defined_ops;
 
   var_expanding_visitor() {}
   void visit_assignment (assignment* e);
+  void visit_defined_op (defined_op* e);
 };
 
 #endif // TAPSETS_H