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, 68 insertions, 1 deletions

diff --git a/staptree.cxx b/staptree.cxx
index 9276586b..cca79981 100644
--- a/staptree.cxx
+++ b/staptree.cxx
@@ -1,5 +1,5 @@
 // parse tree functions
-// 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
@@ -903,6 +903,18 @@ block::block (statement* car, statement* cdr)
 
 
 
+void try_block::print (ostream& o) const
+{
+  o << "try {" << endl;
+  if (try_block) o << *try_block << endl;
+  o << "} catch ";
+  if (catch_error_var) o << "(" << *catch_error_var << ") ";
+  o << "{" << endl;
+  if (catch_block) o << *catch_block << endl;
+  o << "}" << endl;
+}
+
+
 void for_loop::print (ostream& o) const
 {
   o << "for (";
@@ -1140,6 +1152,13 @@ block::visit (visitor* u)
 
 
 void
+try_block::visit (visitor* u)
+{
+  u->visit_try_block (this);
+}
+
+
+void
 embeddedcode::visit (visitor* u)
 {
   u->visit_embeddedcode (this);
@@ -1525,6 +1544,17 @@ traversing_visitor::visit_block (block* s)
 }
 
 void
+traversing_visitor::visit_try_block (try_block* s)
+{
+  if (s->try_block)
+    s->try_block->visit (this);
+  if (s->catch_error_var)
+    s->catch_error_var->visit (this);
+  if (s->catch_block)
+    s->catch_block->visit (this);
+}
+
+void
 traversing_visitor::visit_embeddedcode (embeddedcode*)
 {
 }
@@ -1778,6 +1808,21 @@ functioncall_traversing_visitor::visit_functioncall (functioncall* e)
 
 
 void
+varuse_collecting_visitor::visit_try_block (try_block *s)
+{
+  if (s->try_block)
+    s->try_block->visit (this);
+  if (s->catch_error_var)
+    written.insert (s->catch_error_var->referent);
+  if (s->catch_block)
+    s->catch_block->visit (this);
+
+  // NB: don't functioncall_traversing_visitor::visit_try_block (s);
+  // since that would count s->catch_error_var as a read also.
+}
+
+
+void
 varuse_collecting_visitor::visit_embeddedcode (embeddedcode *s)
 {
   assert (current_function); // only they get embedded code
@@ -2067,6 +2112,13 @@ throwing_visitor::visit_block (block* s)
 }
 
 void
+throwing_visitor::visit_try_block (try_block* s)
+{
+  throwone (s->tok);
+}
+
+
+void
 throwing_visitor::visit_embeddedcode (embeddedcode* s)
 {
   throwone (s->tok);
@@ -2279,6 +2331,15 @@ update_visitor::visit_block (block* s)
 }
 
 void
+update_visitor::visit_try_block (try_block* s)
+{
+  replace (s->try_block);
+  replace (s->catch_error_var);
+  replace (s->catch_block);
+  provide (s);
+}
+
+void
 update_visitor::visit_embeddedcode (embeddedcode* s)
 {
   provide (s);
@@ -2556,6 +2617,12 @@ deep_copy_visitor::visit_block (block* s)
 }
 
 void
+deep_copy_visitor::visit_try_block (try_block* s)
+{
+  update_visitor::visit_try_block(new try_block(*s));
+}
+
+void
 deep_copy_visitor::visit_embeddedcode (embeddedcode* s)
 {
   update_visitor::visit_embeddedcode(new embeddedcode(*s));