Require trivial destructor in allocate_on_obstack

This patch makes allocate_on_obstack a little bit safer, by enforcing
the rule that objects allocated on an obstack must have a trivial
destructor.

The static assert is done in a method -- doing it inside the class
itself won't work because the class is incomplete at that point.

1 files changed, 5 insertions, 1 deletions

diff --git a/gdbsupport/gdb_obstack.h b/gdbsupport/gdb_obstack.h
index 20f8886..7b3bb05 100644
--- a/gdbsupport/gdb_obstack.h
+++ b/gdbsupport/gdb_obstack.h
@@ -133,14 +133,18 @@ struct auto_obstack : obstack
   { obstack_free (this, obstack_base (this)); }
 };
 
-/* Objects are allocated on obstack instead of heap.  */
+/* Objects are allocated on obstack instead of heap.  This is a mixin
+   that uses CRTP to ensure that the type in question is trivially
+   destructible.  */
 
+template<typename T>
 struct allocate_on_obstack
 {
   allocate_on_obstack () = default;
 
   void* operator new (size_t size, struct obstack *obstack)
   {
+    static_assert (IsFreeable<T>::value);
     return obstack_alloc (obstack, size);
   }