1 files changed, 77 insertions, 0 deletions
diff --git a/libstdc++-v3/libsupc++/dyncast.cc b/libstdc++-v3/libsupc++/dyncast.cc
new file mode 100644
index 00000000000..efa53bc0da1
--- /dev/null
+++ b/libstdc++-v3/libsupc++/dyncast.cc
@@ -0,0 +1,77 @@
+// Copyright (C) 1994, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2007
+// Free Software Foundation
+//
+// This file is part of GCC.
+//
+// GCC is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2, or (at your option)
+// any later version.
+
+// GCC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING.  If not, write to
+// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+// Boston, MA 02110-1301, USA. 
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction.  Specifically, if other files instantiate
+// templates or use macros or inline enums from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License.  This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+#include "tinfo.h"
+
+namespace __cxxabiv1 {
+
+
+// this is the external interface to the dynamic cast machinery
+extern "C" void *
+__dynamic_cast (const void *src_ptr,    // object started from
+                const __class_type_info *src_type, // type of the starting object
+                const __class_type_info *dst_type, // desired target type
+                ptrdiff_t src2dst) // how src and dst are related
+{
+  const void *vtable = *static_cast <const void *const *> (src_ptr);
+  const vtable_prefix *prefix =
+      adjust_pointer <vtable_prefix> (vtable, 
+				      -offsetof (vtable_prefix, origin));
+  const void *whole_ptr =
+      adjust_pointer <void> (src_ptr, prefix->whole_object);
+  const __class_type_info *whole_type = prefix->whole_type;
+  __class_type_info::__dyncast_result result;
+  
+  whole_type->__do_dyncast (src2dst, __class_type_info::__contained_public,
+                            dst_type, whole_ptr, src_type, src_ptr, result);
+  if (!result.dst_ptr)
+    return NULL;
+  if (contained_public_p (result.dst2src))
+    // Src is known to be a public base of dst.
+    return const_cast <void *> (result.dst_ptr);
+  if (contained_public_p (__class_type_info::__sub_kind (result.whole2src & result.whole2dst)))
+    // Both src and dst are known to be public bases of whole. Found a valid
+    // cross cast.
+    return const_cast <void *> (result.dst_ptr);
+  if (contained_nonvirtual_p (result.whole2src))
+    // Src is known to be a non-public nonvirtual base of whole, and not a
+    // base of dst. Found an invalid cross cast, which cannot also be a down
+    // cast
+    return NULL;
+  if (result.dst2src == __class_type_info::__unknown)
+    result.dst2src = dst_type->__find_public_src (src2dst, result.dst_ptr,
+                                                  src_type, src_ptr);
+  if (contained_public_p (result.dst2src))
+    // Found a valid down cast
+    return const_cast <void *> (result.dst_ptr);
+  // Must be an invalid down cast, or the cross cast wasn't bettered
+  return NULL;
+}
+
+}