85 lines
4.9 KiB
Ada
85 lines
4.9 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- L A Y O U T --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2000-2020, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING3. If not, go to --
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-- http://www.gnu.org/licenses for a complete copy of the license. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package does front-end layout of types and objects. The result is
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-- to annotate the tree with information on size and alignment of types
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-- and objects. How much layout is performed depends on the setting of the
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-- target dependent parameter Frontend_Layout.
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with Types; use Types;
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package Layout is
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-- The following procedures are called from Freeze, so all entities
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-- for types and objects that get frozen (which should be all such
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-- entities which are seen by the back end) will get laid out by one
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-- of these two procedures.
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procedure Layout_Type (E : Entity_Id);
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-- This procedure may set or adjust the fields Esize, RM_Size and
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-- Alignment in the non-generic type or subtype entity E. If the
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-- Frontend_Layout switch is True, then it is guaranteed that all
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-- three fields will be properly set on return. Regardless of the
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-- Frontend_Layout value, it is guaranteed that all discrete types
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-- will have both Esize and RM_Size fields set on return (since
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-- these are static values). Note that Layout_Type is not called
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-- for generic types, since these play no part in code generation,
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-- and hence representation aspects are irrelevant.
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procedure Layout_Object (E : Entity_Id);
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-- E is either a variable (E_Variable), a constant (E_Constant),
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-- a loop parameter (E_Loop_Parameter), or a formal parameter of
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-- a non-generic subprogram (E_In_Parameter, E_In_Out_Parameter,
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-- or E_Out_Parameter). This procedure may set or adjust the
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-- Esize and Alignment fields of E. If Frontend_Layout is True,
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-- then it is guaranteed that both fields will be properly set
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-- on return. If the Esize is still unknown in the latter case,
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-- it means that the object must be allocated dynamically, since
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-- its length is not known at compile time.
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-- The following are utility routines, called from various places
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procedure Adjust_Esize_Alignment (E : Entity_Id);
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-- E is the entity for a type or object. This procedure checks that the
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-- size and alignment are compatible, and if not either gives an error
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-- message if they cannot be adjusted or else adjusts them appropriately.
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procedure Set_Discrete_RM_Size (Def_Id : Entity_Id);
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-- Set proper RM_Size for discrete size, this is normally the minimum
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-- number of bits to accommodate the range given, except in the case
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-- where the subtype statically matches the first subtype, in which
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-- case the size must be copied from the first subtype. For generic
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-- types, the RM_Size is simply set to zero. This routine also sets
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-- the Is_Constrained flag in Def_Id.
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procedure Set_Elem_Alignment (E : Entity_Id; Align : Nat := 0);
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-- The front end always sets alignments for elementary types by calling
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-- this procedure. Note that we have to do this for discrete types (since
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-- the Alignment attribute is static), so we might as well do it for all
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-- elementary types, as the processing is the same. If Align is nonzero,
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-- it is an external alignment setting that we must respect.
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end Layout;
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