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-- --
-- --
-- L A Y O U T --
-- --
-- S p e c --
-- --
-- Copyright (C) 2000-2021, 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 3, 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 COPYING3. If not, go to --
-- for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
-- This package does front-end layout of types and objects. The result is
-- to annotate the tree with information on size and alignment of types
-- and objects. How much layout is performed depends on the setting of the
-- target dependent parameter Frontend_Layout.
with Types; use Types;
package Layout is
-- The following procedures are called from Freeze, so all entities for
-- types and objects that get frozen (i.e. all types and objects seen by
-- the back end) will get laid out by one of these two procedures.
procedure Layout_Type (E : Entity_Id);
-- This procedure may set or adjust the fields Esize, RM_Size and
-- Alignment in the non-generic type or subtype entity E. If the
-- Frontend_Layout switch is True, then it is guaranteed that all
-- three fields will be properly set on return. Regardless of the
-- Frontend_Layout value, it is guaranteed that all discrete types
-- will have both Esize and RM_Size fields set on return (since
-- these are static values). Note that Layout_Type is not called
-- for generic types, since these play no part in code generation,
-- and hence representation aspects are irrelevant.
procedure Layout_Object (E : Entity_Id);
-- E is either a variable (E_Variable), a constant (E_Constant),
-- a loop parameter (E_Loop_Parameter), or a formal parameter of
-- a non-generic subprogram (E_In_Parameter, E_In_Out_Parameter,
-- or E_Out_Parameter). This procedure may set or adjust the
-- Esize and Alignment fields of E. If Frontend_Layout is True,
-- then it is guaranteed that both fields will be properly set
-- on return. If the Esize is still unknown in the latter case,
-- it means that the object must be allocated dynamically, since
-- its length is not known at compile time.
-- The following are utility routines, called from various places
procedure Adjust_Esize_Alignment (E : Entity_Id);
-- E is the entity for a type or object. This procedure checks that the
-- size and alignment are compatible, and if not either gives an error
-- message if they cannot be adjusted or else adjusts them appropriately.
procedure Set_Discrete_RM_Size (Def_Id : Entity_Id);
-- Set proper RM_Size for discrete size, this is normally the minimum
-- number of bits to accommodate the range given, except in the case
-- where the subtype statically matches the first subtype, in which
-- case the size must be copied from the first subtype. For generic
-- types, the RM_Size is simply set to zero. This routine also sets
-- the Is_Constrained flag in Def_Id.
procedure Set_Elem_Alignment (E : Entity_Id; Align : Nat := 0);
-- The front end always sets alignments for elementary types by calling
-- this procedure. Note that we have to do this for discrete types (since
-- the Alignment attribute is static), so we might as well do it for all
-- elementary types, as the processing is the same. If Align is nonzero,
-- it is an external alignment setting that we must respect.
end Layout;