PR5930: Address-op for $target and @cast members

This allows the '&' operator to get the address of @cast and $target
variable expressions.

* staptree.h (target_symbol): add addressof field
* staptree.cxx (target_symbol::print): print '&' for addressof
  (cast_op::print): ditto
* parse.cxx (parser::parse_value): allow '&' prefix on $target/@cast
* dwflpp.cxx (dwflpp::translate_final_fetch_or_store): allow taking the
  computed address without actually doing a final fetch.
* tapset* (*::visit_target_symbol): throw errors for $vars w/o addresses
* testsuite/systemtap.base/cast.stp: add &@cast test
* testsuite/semok/target_addr.stp: test '&' on different member types
* testsuite/semko/target_addr?.stp: test failure on bitfields/registers

1 files changed, 12 insertions, 0 deletions

diff --git a/parse.cxx b/parse.cxx
index f3b9eb09..35c78abe 100644
--- a/parse.cxx
+++ b/parse.cxx
@@ -2239,6 +2239,18 @@ parser::parse_value ()
         throw parse_error ("expected ')'");
       return e;
     }
+  else if (t->type == tok_operator && t->content == "&")
+    {
+      next ();
+      t = peek ();
+      if (t->type != tok_identifier ||
+          (t->content != "@cast" && t->content[0] != '$'))
+        throw parse_error ("expected @cast or $var");
+
+      target_symbol *ts = static_cast<target_symbol*>(parse_symbol());
+      ts->addressof = true;
+      return ts;
+    }
   else if (t->type == tok_identifier)
     return parse_symbol ();
   else