| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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; |
