re PR c++/44613 (Declaring an array with non-constant length inside a switch…

re PR c++/44613 (Declaring an array with non-constant length inside a switch corrupts stack pointer.)

	PR c++/44613
	* semantics.c (add_stmt): Set STATEMENT_LIST_HAS_LABEL.
	* decl.c (cp_finish_decl): Create a new BIND_EXPR before
	instantiating a variable-sized type.

From-SVN: r209125

gcc/cp/ChangeLog

 2014-04-04  Patrick Palka  <patrick@parcs.ath.cx>
 
+	PR c++/44613
+	* semantics.c (add_stmt): Set STATEMENT_LIST_HAS_LABEL.
+	* decl.c (cp_finish_decl): Create a new BIND_EXPR before
+	instantiating a variable-sized type.
+
 	PR c++/21113
 	* decl.c (decl_jump_unsafe): Consider variably-modified decls.
 

gcc/cp/decl.c

@@ -6440,7 +6440,24 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
      after the call to check_initializer so that the DECL_EXPR for a
      reference temp is added before the DECL_EXPR for the reference itself.  */
   if (DECL_FUNCTION_SCOPE_P (decl))
-    add_decl_expr (decl);
+    {
+      /* If we're building a variable sized type, and we might be
+	 reachable other than via the top of the current binding
+	 level, then create a new BIND_EXPR so that we deallocate
+	 the object at the right time.  */
+      if (VAR_P (decl)
+	  && DECL_SIZE (decl)
+	  && !TREE_CONSTANT (DECL_SIZE (decl))
+	  && STATEMENT_LIST_HAS_LABEL (cur_stmt_list))
+	{
+	  tree bind;
+	  bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
+	  TREE_SIDE_EFFECTS (bind) = 1;
+	  add_stmt (bind);
+	  BIND_EXPR_BODY (bind) = push_stmt_list ();
+	}
+      add_decl_expr (decl);
+    }
 
   /* Let the middle end know about variables and functions -- but not
      static data members in uninstantiated class templates.  */

gcc/cp/semantics.c

@@ -386,6 +386,9 @@ add_stmt (tree t)
       STMT_IS_FULL_EXPR_P (t) = stmts_are_full_exprs_p ();
     }
 
+  if (code == LABEL_EXPR || code == CASE_LABEL_EXPR)
+    STATEMENT_LIST_HAS_LABEL (cur_stmt_list) = 1;
+
   /* Add T to the statement-tree.  Non-side-effect statements need to be
      recorded during statement expressions.  */
   gcc_checking_assert (!stmt_list_stack->is_empty ());

gcc/testsuite/g++.dg/ext/vla15.C

+// PR c++/44613
+// { dg-do run }
+// { dg-options "" }
+
+void *volatile p;
+
+int
+main (void)
+{
+  int n = 0;
+ lab:;
+  int x[n % 1000 + 1];
+  x[0] = 1;
+  x[n % 1000] = 2;
+  p = x;
+  n++;
+  if (n < 1000000)
+    goto lab;
+  return 0;
+}