cp-tree.def (LABEL_STMT): New tree node.

	* cp-tree.def (LABEL_STMT): New tree node.
	(LABEL_STMT_LABEL): New macro.
	(shadow_label): Remove.
	(declare_local_label): New function.
	(finish_label_decl): Likewise.
	* decl.c (make_label_decl): New function, split out from
	lookup_label.
	(shadowed_labels): Remove.
	(binding_level): Add shadowed_labels.
	(clear_binding_level): Remove.
	(push_binding_level): Just bzero the new binding level.
	(pushlevel): Fix indentation.
	(pop_label): New function.
	(pop_labels): Likewise, split out from poplevel.
	(poplevel): Pop local labels.  Use pop_labels.
	(maybe_push_to_top_level): Don't clear shadowed_labels.
	(lookup_label): Use make_label_decl.
	(shadow_label): Remove.
	(declare_local_label): New function.
	(define_label): Simplify.
	(start_function): Don't clear shadowed_labels.
	(cp_function): Remove shadowed_labels.
	(push_cp_function_context): Don't save shadowed_labels.
	(pop_cp_function_context): Don't restore it.
	* dump.c (dequeue_and_dump): Handle LABEL_STMT.
	* parse.y (label_decl): Use finish_label_decl.
	* pt.c (tsubst_expr): Handle LABEL_STMTs, and local label
	declarations.
	* semantics.c (finish_label_stmt): Add a LABEL_STMT when
	building_stmt_tree.
	(finish_label_decl): New function.
	(expand_stmt): Handle LABEL_STMTs and local label declarations.

From-SVN: r28943

gcc/cp/ChangeLog

+1999-08-28  Mark Mitchell  <mark@codesourcery.com>
+
+	* cp-tree.def (LABEL_STMT): New tree node.
+	(LABEL_STMT_LABEL): New macro.
+	(shadow_label): Remove.
+	(declare_local_label): New function.
+	(finish_label_decl): Likewise.
+	* decl.c (make_label_decl): New function, split out from
+	lookup_label.
+	(shadowed_labels): Remove.
+	(binding_level): Add shadowed_labels.
+	(clear_binding_level): Remove.
+	(push_binding_level): Just bzero the new binding level.
+	(pushlevel): Fix indentation.
+	(pop_label): New function.
+	(pop_labels): Likewise, split out from poplevel.
+	(poplevel): Pop local labels.  Use pop_labels.
+	(maybe_push_to_top_level): Don't clear shadowed_labels.
+	(lookup_label): Use make_label_decl.
+	(shadow_label): Remove.
+	(declare_local_label): New function.
+	(define_label): Simplify.
+	(start_function): Don't clear shadowed_labels.
+	(cp_function): Remove shadowed_labels.
+	(push_cp_function_context): Don't save shadowed_labels.
+	(pop_cp_function_context): Don't restore it.
+	* dump.c (dequeue_and_dump): Handle LABEL_STMT.
+	* parse.y (label_decl): Use finish_label_decl.
+	* pt.c (tsubst_expr): Handle LABEL_STMTs, and local label
+	declarations.
+	* semantics.c (finish_label_stmt): Add a LABEL_STMT when
+	building_stmt_tree.
+	(finish_label_decl): New function.
+	(expand_stmt): Handle LABEL_STMTs and local label declarations.
+	
 1999-08-26  Mark Mitchell  <mark@codesourcery.com>
 
 	* decl.c (lookup_label): Build labels on the permanent obstack

gcc/cp/cp-tree.def

@@ -228,6 +228,7 @@ DEFTREECODE (BREAK_STMT, "break_stmt", 'e', 0)
 DEFTREECODE (CONTINUE_STMT, "continue_stmt", 'e', 0)
 DEFTREECODE (SWITCH_STMT, "switch_stmt", 'e', 2)
 DEFTREECODE (GOTO_STMT, "goto_stmt", 'e', 1)
+DEFTREECODE (LABEL_STMT, "label_stmt", 'e', 1)
 DEFTREECODE (ASM_STMT, "asm_stmt", 'e', 5)
 /* A SUBOBJECT statement marks the point at which a sub-object is
    fully constructed.  After this point, the SUBOBJECT_CLEANUP must be

gcc/cp/dump.c

@@ -731,6 +731,13 @@ dequeue_and_dump (di)
       dump_next_stmt (di, t);
       break;
 
+    case LABEL_STMT:
+      dump_stmt (di, t);
+      if (dump_children_p)
+	dump_child ("labl", LABEL_STMT_LABEL (t));
+      dump_next_stmt (di, t);
+      break;
+
     case RETURN_STMT:
       dump_stmt (di, t);
       if (dump_children_p)

gcc/cp/parse.y

@@ -3168,12 +3168,11 @@ label_decls:
 
 label_decl:
 	  LABEL identifiers_or_typenames ';'
-		{ tree link;
-		  for (link = $2; link; link = TREE_CHAIN (link))
+                { 
+		  while ($2)
 		    {
-		      tree label = shadow_label (TREE_VALUE (link));
-		      C_DECLARED_LABEL_FLAG (label) = 1;
-		      declare_nonlocal_label (label);
+		      finish_label_decl (TREE_VALUE ($2));
+		      $2 = TREE_CHAIN ($2);
 		    }
 		}
 	;

gcc/cp/pt.c

@@ -7264,18 +7264,23 @@ tsubst_expr (t, args, complain, in_decl)
 
 	lineno = STMT_LINENO (t);
 	decl = DECL_STMT_DECL (t);
-	init = DECL_INITIAL (decl);
-	decl = tsubst (decl, args, complain, in_decl);
-	init = tsubst_expr (init, args, complain, in_decl);
-	DECL_INITIAL (decl) = init;
-	/* By marking the declaration as instantiated, we avoid trying
+	if (TREE_CODE (decl) == LABEL_DECL)
+	  finish_label_decl (DECL_NAME (decl));
+	else
+	  {
+	    init = DECL_INITIAL (decl);
+	    decl = tsubst (decl, args, complain, in_decl);
+	    init = tsubst_expr (init, args, complain, in_decl);
+	    DECL_INITIAL (decl) = init;
+	    /* By marking the declaration as instantiated, we avoid trying
 	   to instantiate it.  Since instantiate_decl can't handle
 	   local variables, and since we've already done all that
 	   needs to be done, that's the right thing to do.  */
-	if (TREE_CODE (decl) == VAR_DECL)
-	  DECL_TEMPLATE_INSTANTIATED (decl) = 1;
-	maybe_push_decl (decl);
-	add_decl_stmt (decl);
+	    if (TREE_CODE (decl) == VAR_DECL)
+	      DECL_TEMPLATE_INSTANTIATED (decl) = 1;
+	    maybe_push_decl (decl);
+	    add_decl_stmt (decl);
+	  }
 	resume_momentary (i);
 	return decl;
       }
@@ -7392,10 +7397,9 @@ tsubst_expr (t, args, complain, in_decl)
 			 tsubst_expr (CASE_HIGH (t), args, complain, in_decl));
       break;
 
-    case LABEL_DECL:
-      lineno = DECL_SOURCE_LINE (t);
-      input_filename = DECL_SOURCE_FILE (t);
-      finish_label_stmt (DECL_NAME (t));
+    case LABEL_STMT:
+      lineno = STMT_LINENO (t);
+      finish_label_stmt (DECL_NAME (LABEL_STMT_LABEL (t)));
       break;
 
     case GOTO_STMT:

gcc/cp/semantics.c

@@ -919,11 +919,24 @@ finish_label_stmt (name)
   tree decl = define_label (input_filename, lineno, name);
 
   if (building_stmt_tree ())
-    add_tree (decl);
+    add_tree (build_min_nt (LABEL_STMT, decl));
   else if (decl)
     expand_label (decl);
 }
 
+/* Finish a series of declarations for local labels.  G++ allows users
+   to declare "local" labels, i.e., labels with scope.  This extension
+   is useful when writing code involving statement-expressions.  */
+
+void
+finish_label_decl (name)
+     tree name;
+{
+  tree decl = declare_local_label (name);
+  if (building_stmt_tree ())
+    add_decl_stmt (decl);
+}
+
 /* Create a declaration statement for the declaration given by the
    DECL.  */
 
@@ -2019,17 +2032,22 @@ expand_stmt (t)
 	lineno = STMT_LINENO (t);
 	emit_line_note (input_filename, lineno);
 	decl = DECL_STMT_DECL (t);
-	/* We need to clear DECL_CONTEXT so that maybe_push_decl
-	   will push it into the current scope.  */
-	if (DECL_CONTEXT (decl) == current_function_decl)
-	  DECL_CONTEXT (decl) = NULL_TREE;
-	/* If we marked this variable as dead when we processed it
-	   before, we must undo that now.  The variable has been
-	   resuscitated.  */
-	if (TREE_CODE (decl) == VAR_DECL)
-	  DECL_DEAD_FOR_LOCAL (decl) = 0;
-	maybe_push_decl (decl);
-	cp_finish_decl (decl, DECL_INITIAL (decl), NULL_TREE, 0, 0);
+	if (TREE_CODE (decl) == LABEL_DECL)
+	  finish_label_decl (DECL_NAME (decl));
+	else
+	  {
+	    /* We need to clear DECL_CONTEXT so that maybe_push_decl
+	       will push it into the current scope.  */
+	    if (DECL_CONTEXT (decl) == current_function_decl)
+	      DECL_CONTEXT (decl) = NULL_TREE;
+	    /* If we marked this variable as dead when we processed it
+	       before, we must undo that now.  The variable has been
+	       resuscitated.  */
+	    if (TREE_CODE (decl) == VAR_DECL)
+	      DECL_DEAD_FOR_LOCAL (decl) = 0;
+	    maybe_push_decl (decl);
+	    cp_finish_decl (decl, DECL_INITIAL (decl), NULL_TREE, 0, 0);
+	  }
 	resume_momentary (i);
       }
       break;
@@ -2119,15 +2137,17 @@ expand_stmt (t)
       finish_case_label (CASE_LOW (t), CASE_HIGH (t));
       break;
 
-    case LABEL_DECL:
-      input_filename = DECL_SOURCE_FILE (t);
-      lineno = DECL_SOURCE_LINE (t);
-      finish_label_stmt (DECL_NAME (t));
+    case LABEL_STMT:
+      lineno = STMT_LINENO (t);
+      finish_label_stmt (DECL_NAME (LABEL_STMT_LABEL (t)));
       break;
 
     case GOTO_STMT:
       lineno = STMT_LINENO (t);
-      finish_goto_stmt (GOTO_DESTINATION (t));
+      if (TREE_CODE (GOTO_DESTINATION (t)) == LABEL_DECL)
+	finish_goto_stmt (DECL_NAME (GOTO_DESTINATION (t)));
+      else
+	finish_goto_stmt (GOTO_DESTINATION (t));
       break;
 
     case ASM_STMT:

gcc/testsuite/g++.old-deja/g++.ext/label1.C

+// Origin: Mark Mitchell <mark@codesourcery.com>
+// Special g++ Options:
+
+int main ()
+{
+  int i = 0;
+  int j = 0;
+  int k = 0;
+
+ l:
+  if (j)
+    return 0;
+  ({
+    __label__ l; 
+    k = 0;
+  l: 
+    if (++k <= 2)
+      goto l;
+    ++i;});
+  if (i > 1 || k != 3)
+    return 1;
+  else
+    {
+      j = 1;
+      goto l;
+    }
+}

gcc/testsuite/g++.old-deja/g++.ext/label2.C

+// Origin: Mark Mitchell <mark@codesourcery.com>
+// Special g++ Options:
+
+template <class T>
+int f ()
+{
+  int i = 0;
+  int j = 0;
+  int k = 0;
+
+ l:
+  if (j)
+    return 0;
+  ({
+    __label__ l; 
+    k = 0;
+  l: 
+    if (++k <= 2)
+      goto l;
+    ++i;});
+  if (i > 1 || k != 3)
+    return 1;
+  else
+    {
+      j = 1;
+      goto l;
+    }
+}
+
+int main ()
+{
+  return f<double>();
+}
+

gcc/testsuite/g++.old-deja/g++.pt/goto2.C

+// Build don't link:
+// Origin: Mark Mitchell <mark@codesourcery.com>
+
+int i = 1;
+
+template <class T> void test()
+{
+  goto lab;
+ lab: 
+  --i;
+}
+
+int main ()
+{
+  test<int>();
+  return i;
+}