------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- I T Y P E S -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2003 Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT 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 distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This package contains declarations for handling of implicit types with Einfo; use Einfo; with Sem_Util; use Sem_Util; with Types; use Types; package Itypes is -------------------- -- Implicit Types -- -------------------- -- Implicit types are types and subtypes created by the semantic phase -- or the expander to reflect the underlying semantics. These could be -- generated by building trees for corresponding declarations and then -- analyzing these trees, but there are three reasons for not doing this: -- 1. The declarations would require more tree nodes -- 2. In some cases, the elaboration of these types is associated -- with internal nodes in the tree. -- 3. For some types, notably class wide types, there is no Ada -- declaration that would correspond to the desired entity. -- So instead, implicit types are constructed by simply creating an -- appropriate entity with the help of routines in this package. These -- entities are fully decorated, as described in Einfo (just as though -- they had been created by the normal analysis procedure). -- The type declaration declaring an Itype must be analyzed with checks -- off because this declaration has not been inserted in the tree (if it -- has been then it is not an itype), and hence checks that would be -- generated during the analysis cannot be inserted in the tree. At any -- rate, itype analysis should always be done with checks off, otherwise -- duplicate checks will most likely be emitted. -- Unlike types declared explicitly, implicit types are defined on first -- use, which means that Gigi detects the use of such types, and defines -- them at the point of the first use automatically. -- Although Itypes are not explicitly declared, they are associated with -- a specific node in the tree (roughly the node that caused them to be -- created), via the Associated_Node_For_Itype field. This association is -- used particularly by New_Copy_Tree, which uses it to determine whether -- or not to copy a referenced Itype. If the associated node is part of -- the tree to be copied by New_Copy_Tree, then (since the idea of the -- call to New_Copy_Tree is to create a complete duplicate of a tree, -- as though it had appeared separately in the source), the Itype in -- question is duplicated as part of the New_Copy_Tree processing. ----------------- -- Subprograms -- ----------------- function Create_Itype (Ekind : Entity_Kind; Related_Nod : Node_Id; Related_Id : Entity_Id := Empty; Suffix : Character := ' '; Suffix_Index : Nat := 0; Scope_Id : Entity_Id := Current_Scope) return Entity_Id; -- Used to create a new Itype. -- -- Related_Nod is the node for which this Itype was created. It is -- set as the Associated_Node_For_Itype of the new itype. The Sloc of -- the new Itype is that of this node. -- -- Related_Id is present only if the implicit type name may be referenced -- as a public symbol, and thus needs a unique external name. The name -- is created by a call to: -- -- New_External_Name (Chars (Related_Id), Suffix, Suffix_Index, 'T') -- -- If the implicit type does not need an external name, then the -- Related_Id parameter is omitted (and hence Empty). In this case -- Suffix and Suffix_Index are ignored and the implicit type name is -- created by a call to New_Internal_Name ('T'). -- -- Note that in all cases, the name starts with "T". This is used -- to identify implicit types in the error message handling circuits. -- -- The Scope_Id parameter specifies the scope of the created type, and -- is normally the Current_Scope as shown, but can be set otherwise. end Itypes;