* gigi.h (standard_datatypes): Add ADT_fdesc_type and ADT_null_fdesc.

[pf3gnuchains/gcc-fork.git] / gcc / ada / trans.c

diff --git a/gcc/ada/trans.c b/gcc/ada/trans.c
index a6440d5..4dc5202 100644 (file)
--- a/gcc/ada/trans.c
+++ b/gcc/ada/trans.c
@@ -852,6 +852,53 @@ Attribute_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, int attribute)
       if (attribute == Attr_Address)
        gnu_prefix = maybe_unconstrained_array (gnu_prefix);
 
+      /* If we are building a static dispatch table, we have to honor
+        TARGET_VTABLE_USES_DESCRIPTORS if we want to be compatible
+        with the C++ ABI.  We do it in the non-static case as well,
+        see gnat_to_gnu_entity, case E_Access_Subprogram_Type.  */
+      else if (TARGET_VTABLE_USES_DESCRIPTORS
+              && Is_Dispatch_Table_Entity (Etype (gnat_node)))
+       {
+         tree gnu_field, gnu_list = NULL_TREE, t;
+         /* Descriptors can only be built here for top-level functions.  */
+         bool build_descriptor = (global_bindings_p () != 0);
+         int i;
+
+         gnu_result_type = get_unpadded_type (Etype (gnat_node));
+
+         /* If we're not going to build the descriptor, we have to retrieve
+            the one which will be built by the linker (or by the compiler
+            later if a static chain is requested).  */
+         if (!build_descriptor)
+           {
+             gnu_result = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_prefix);
+             gnu_result = fold_convert (build_pointer_type (gnu_result_type),
+                                        gnu_result);
+             gnu_result = build1 (INDIRECT_REF, gnu_result_type, gnu_result);
+           }
+
+         for (gnu_field = TYPE_FIELDS (gnu_result_type), i = 0;
+              i < TARGET_VTABLE_USES_DESCRIPTORS;
+              gnu_field = TREE_CHAIN (gnu_field), i++)
+           {
+             if (build_descriptor)
+               {
+                 t = build2 (FDESC_EXPR, TREE_TYPE (gnu_field), gnu_prefix,
+                             build_int_cst (NULL_TREE, i));
+                 TREE_CONSTANT (t) = 1;
+                 TREE_INVARIANT (t) = 1;
+               }
+             else
+               t = build3 (COMPONENT_REF, ptr_void_ftype, gnu_result,
+                           gnu_field, NULL_TREE);
+
+             gnu_list = tree_cons (gnu_field, t, gnu_list);
+           }
+
+         gnu_result = gnat_build_constructor (gnu_result_type, gnu_list);
+         break;
+       }
+
       /* ... fall through ... */
 
     case Attr_Access:
@@ -3649,7 +3696,12 @@ gnat_to_gnu (Node_Id gnat_node)
       break;
 
     case N_Null:
-      gnu_result = null_pointer_node;
+      if (TARGET_VTABLE_USES_DESCRIPTORS
+         && Ekind (Etype (gnat_node)) == E_Access_Subprogram_Type
+         && Is_Dispatch_Table_Entity (Etype (gnat_node)))
+       gnu_result = null_fdesc_node;
+      else
+       gnu_result = null_pointer_node;
       gnu_result_type = get_unpadded_type (Etype (gnat_node));
       break;
 
@@ -3687,6 +3739,13 @@ gnat_to_gnu (Node_Id gnat_node)
               size_int (align / BITS_PER_UNIT), oalign / BITS_PER_UNIT);
        }
 
+      /* If we are converting a descriptor to a function pointer, first
+        build the pointer.  */
+      if (TARGET_VTABLE_USES_DESCRIPTORS
+         && TREE_TYPE (gnu_result) == fdesc_type_node
+         && POINTER_TYPE_P (gnu_result_type))
+       gnu_result = build_unary_op (ADDR_EXPR, NULL_TREE, gnu_result);
+
       gnu_result = unchecked_convert (gnu_result_type, gnu_result,
                                      No_Truncation (gnat_node));
       break;