------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- L A Y O U T -- -- -- -- S p e c -- -- -- -- Copyright (C) 2000-2007, 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 -- -- http://www.gnu.org/licenses 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 Backend_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 (which should be all such -- entities which are seen by the back end) will get layed 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 -- Backend_Layout switch is False, then it is guaranteed that all -- three fields will be properly set on return. Regardless of the -- Backend_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 Backend_Layout is False, -- 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); -- 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, since the processing is the same. end Layout;