------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ T S S -- -- -- -- S p e c -- -- -- -- -- -- 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. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- 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;