| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ T S S -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- $Revision: 1.7 $ |
| -- -- |
| -- Copyright (C) 1992-2001 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. -- |
| -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- Type Support Subprogram (TSS) handling |
| |
| with Types; use Types; |
| |
| package Exp_Tss is |
| |
| -- A type support subprogram (TSS) is an internally generated function or |
| -- procedure that is associated with a particular type. Examples are the |
| -- implicit initialization procedure, and subprograms for the Input and |
| -- Output attributes. |
| |
| -- A given TSS is either generated once at the point of the declaration of |
| -- the type, or it is generated as needed in clients, but only one copy is |
| -- required in any one generated object file. The choice between these two |
| -- possibilities is made on a TSS-by-TSS basis depending on the estimation |
| -- of how likely the TSS is to be used. Initialization procedures fall in |
| -- the first category, for example, since it is likely that any declared |
| -- type will be used in a context requiring initialization, but the stream |
| -- attributes use the second approach, since it is more likely that they |
| -- will not be used at all, or will only be used in one client in any case. |
| |
| -- A TSS is identified by its Chars name, i.e. for a given TSS type, the |
| -- same name is used for all types, e.g. the initialization routine has |
| -- the name _init for all types. |
| |
| -- The TSS's for a given type are stored in an element list associated with |
| -- the type, and referenced from the TSS_Elist field of the N_Freeze_Entity |
| -- node associated with the type (all types that need TSS's always need to |
| -- be explicitly frozen, so the N_Freeze_Entity node always exists). |
| |
| function TSS (Typ : Entity_Id; Nam : Name_Id) return Entity_Id; |
| -- Finds the TSS with the given name associated with the given type. If |
| -- no such TSS exists, then Empty is returned. |
| |
| procedure Set_TSS (Typ : Entity_Id; TSS : Entity_Id); |
| -- This procedure is used to install a newly created TSS. The second |
| -- argument is the entity for such a new TSS. This entity is placed in |
| -- the TSS list for the type given as the first argument, replacing an |
| -- old entry of the same name if one was present. The tree for the body |
| -- of this TSS, which is not analyzed yet, is placed in the actions field |
| -- of the freeze node for the type. All such bodies are inserted into the |
| -- main tree and analyzed at the point at which the freeze node itself is |
| -- is expanded. |
| |
| procedure Copy_TSS (TSS : Entity_Id; Typ : Entity_Id); |
| -- Given an existing TSS for another type (which is already installed, |
| -- analyzed and expanded), install it as the corresponding TSS for Typ. |
| -- Note that this just copies a reference, not the tree. This can also |
| -- be used to initially install a TSS in the case where the subprogram |
| -- for the TSS has already been created and its declaration processed. |
| |
| function Init_Proc (Typ : Entity_Id) return Entity_Id; |
| pragma Inline (Init_Proc); |
| -- Obtains the _init TSS entry for the given type. This function call is |
| -- equivalent to TSS (Typ, Name_uInit). The _init TSS is the procedure |
| -- used to initialize otherwise uninitialized instances of a type. If |
| -- there is no _init TSS, then the type requires no initialization. Note |
| -- that subtypes and implicit types never have an _init TSS since subtype |
| -- objects are always initialized using the initialization procedure for |
| -- the corresponding base type (see Base_Init_Proc function). A special |
| -- case arises for concurrent types. Such types do not themselves have an |
| -- _init TSR, but initialization is required. The initialization procedure |
| -- used is the one fot the corresponding record type (see Base_Init_Proc). |
| |
| function Base_Init_Proc (Typ : Entity_Id) return Entity_Id; |
| -- Obtains the _Init TSS entry from the base type of the entity, and also |
| -- deals with going indirect through the Corresponding_Record_Type field |
| -- for concurrent objects (which are initialized with the initialization |
| -- routine for the corresponding record type). Returns Empty if there is |
| -- no _Init TSS entry for the base type. |
| |
| procedure Set_Init_Proc (Typ : Entity_Id; Init : Entity_Id); |
| pragma Inline (Set_Init_Proc); |
| -- The second argument is the _init TSS to be established for the type |
| -- given as the first argument. Equivalent to Set_TSS (Typ, Init). |
| |
| function Has_Non_Null_Base_Init_Proc (Typ : Entity_Id) return Boolean; |
| -- Returns true if the given type has a defined Base_Init_Proc and |
| -- this init proc is not a null init proc (null init procs occur as |
| -- a result of the processing for Initialize_Scalars. This function |
| -- is used to test for the presence of an Init_Proc in cases where |
| -- a null init proc is considered equivalent to no Init_Proc. |
| |
| end Exp_Tss; |
