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