PR11004: try / catch error-handling script syntax

* parse.h (try_block): New class.  Update basic visitors.
* staptree.cxx: Implement basic visitors.
* parse.cxx (expect_kw): Fix to actually look for keywords.
  (parse_try_block): New function.
  (lexer ctor): Designate 'try' and 'catch' as keywords.
* elaborate.cxx (dead_assignment_remover, dead_statmtexpr_remover): Optimize.
  (other visitors): Implement.
* translate.cxx (c_unparser): Implement via super-handy __local__ labels.
  (emit_probe, emit_function): Make outer out: label also __local__.
* testsuite/buildok/fortyone.stp, semko/fortynine.stp,
  systemtap.base/trycatch.exp: Test it.
* NEWS, doc/langref.txt, stap.1.in: Document it.

1 files changed, 2 insertions, 0 deletions

diff --git a/parse.h b/parse.h
index 8f34442a..2b2dd3ac 100644
--- a/parse.h
+++ b/parse.h
@@ -102,6 +102,7 @@ struct embeddedcode;
 struct probe_point;
 struct literal;
 struct block;
+struct try_block;
 struct for_loop;
 struct statement;
 struct if_statement;
@@ -175,6 +176,7 @@ private: // nonterminals
   probe_point* parse_probe_point ();
   literal* parse_literal ();
   block* parse_stmt_block ();
+  try_block* parse_try_block ();
   statement* parse_statement ();
   if_statement* parse_if_statement ();
   for_loop* parse_for_loop ();