blob: 3abdffb80735ecadbe29d5d385ca0efd9d78e72e [file] [log] [blame]
-- --
-- --
-- S E M _ C H 1 3 --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2003 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. --
-- --
with Types; use Types;
with Uintp; use Uintp;
package Sem_Ch13 is
procedure Analyze_At_Clause (N : Node_Id);
procedure Analyze_Attribute_Definition_Clause (N : Node_Id);
procedure Analyze_Enumeration_Representation_Clause (N : Node_Id);
procedure Analyze_Free_Statement (N : Node_Id);
procedure Analyze_Record_Representation_Clause (N : Node_Id);
procedure Analyze_Code_Statement (N : Node_Id);
procedure Initialize;
-- Initialize internal tables for new compilation
procedure Set_Enum_Esize (T : Entity_Id);
-- This routine sets the Esize field for an enumeration type T, based
-- on the current representation information available for T. Note that
-- the setting of the RM_Size field is not affected. This routine also
-- initializes the alignment field to zero.
function Minimum_Size
(T : Entity_Id;
Biased : Boolean := False)
return Nat;
-- Given a primitive type, determines the minimum number of bits required
-- to represent all values of the type. This function may not be called
-- with any other types. If the flag Biased is set True, then the minimum
-- size calculation that biased representation is used in the case of a
-- discrete type, e.g. the range 7..8 gives a minimum size of 4 with
-- Biased set to False, and 1 with Biased set to True. Note that the
-- biased parameter only has an effect if the type is not biased, it
-- causes Minimum_Size to indicate the minimum size of an object with
-- the given type, of the size the type would have if it were biased. If
-- the type is already biased, then Minimum_Size returns the biased size,
-- regardless of the setting of Biased. Also, fixed-point types are never
-- biased in the current implementation.
procedure Check_Constant_Address_Clause (Expr : Node_Id; U_Ent : Entity_Id);
-- Expr is an expression for an address clause. This procedure checks
-- that the expression is constant, in the limited sense that it is safe
-- to evaluate it at the point the object U_Ent is declared, rather than
-- at the point of the address clause. The condition for this to be true
-- is that the expression has no variables, no constants declared after
-- U_Ent, and no calls to non-pure functions. If this condition is not
-- met, then an appropriate error message is posted. This check is applied
-- at the point an object with an address clause is frozen, as well as for
-- address clauses for tasks and entries.
procedure Check_Size
(N : Node_Id;
T : Entity_Id;
Siz : Uint;
Biased : out Boolean);
-- Called when size Siz is specified for subtype T. This subprogram checks
-- that the size is appropriate, posting errors on node N as required.
-- This check is effective for elementary types and bit-packed arrays.
-- For other non-elementary types, a check is only made if an explicit
-- size has been given for the type (and the specified size must match).
-- The parameter Biased is set False if the size specified did not require
-- the use of biased representation, and True if biased representation
-- was required to meet the size requirement. Note that Biased is only
-- set if the type is not currently biased, but biasing it is the only
-- way to meet the requirement. If the type is currently biased, then
-- this biased size is used in the initial check, and Biased is False.
-- If the size is too small, and an error message is given, then both
-- Esize and RM_Size are reset to the allowed minimum value in T.
procedure Record_Rep_Item (T : Entity_Id; N : Node_Id);
-- N is the node for either a representation pragma or an attribute
-- definition clause that applies to type T. This procedure links
-- the node N onto the Rep_Item chain for the type T.
function Rep_Item_Too_Early
(T : Entity_Id;
N : Node_Id)
return Boolean;
-- Called at the start of processing a representation clause or a
-- representation pragma. Used to check that the representation item
-- is not being applied to an incompleted type or to a generic formal
-- type or a type derived from a generic formal type. Returns False if
-- no such error occurs. If this error does occur, appropriate error
-- messages are posted on node N, and True is returned.
function Rep_Item_Too_Late
(T : Entity_Id;
N : Node_Id;
FOnly : Boolean := False)
return Boolean;
-- Called at the start of processing a representation clause or a
-- representation pragma. Used to check that a representation item
-- for entity T does not appear too late (according to the rules in
-- RM 13.1(9) and RM 13.1(10)). N is the associated node, which in
-- the pragma case is the pragma or representation clause itself, used
-- for placing error messages if the item is too late.
-- Fonly is a flag that causes only the freezing rule (para 9) to be
-- applied, and the tests of para 10 are skipped. This is appropriate
-- for both subtype related attributes (Alignment and Size) and for
-- stream attributes, which, although certainly not subtype related
-- attributes, clearly should not be subject to the para 10 restrictions
-- (see AI95-00137). Similarly, we also skip the para 10 restrictions for
-- the Storage_Size case where they also clearly do not apply.
-- If the rep item is too late, an appropriate message is output and
-- True is returned, which is a signal that the caller should abandon
-- processing for the item. If the item is not too late, then False
-- is returned, and the caller can continue processing the item.
-- If no error is detected, this call also as a side effect links the
-- representation item onto the head of the representation item chain
-- (referenced by the First_Rep_Item field of the entity).
-- Note: Rep_Item_Too_Late must be called with the underlying type in
-- the case of a private or incomplete type. The protocol is to first
-- check for Rep_Item_Too_Early using the initial entity, then take the
-- underlying type, then call Rep_Item_Too_Late on the result.
function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean;
-- Given two types, where the two types are related by possible derivation,
-- determines if the two types have the same representation, or different
-- representations, requiring the special processing for representation
-- change. A False result is possible only for array, enumeration or
-- record types.
procedure Validate_Unchecked_Conversion
(N : Node_Id;
Act_Unit : Entity_Id);
-- Validate a call to unchecked conversion. N is the node for the actual
-- instantiation, which is used only for error messages. Act_Unit is the
-- entity for the instantiation, from which the actual types etc for this
-- instantiation can be determined. This procedure makes an entry in a
-- table and/or generates an N_Validate_Unchecked_Conversion node. The
-- actual checking is done in Validate_Unchecked_Conversions or in the
-- back end as required.
procedure Validate_Unchecked_Conversions;
-- This routine is called after calling the backend to validate
-- unchecked conversions for size and alignment appropriateness.
-- The reason it is called that late is to take advantage of any
-- back-annotation of size and alignment performed by the backend.
end Sem_Ch13;