------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 1 3 -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2004 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, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, 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 an elementary 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. 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;