1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ D I S P -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2002 Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 2, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING. If not, write -- 19-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- GNAT was originally developed by the GNAT team at New York University. -- 23-- Extensive contributions were provided by Ada Core Technologies Inc. -- 24-- -- 25------------------------------------------------------------------------------ 26 27-- This package contains routines involved in tagged types and dynamic 28-- dispatching. 29 30with Types; use Types; 31package Sem_Disp is 32 33 procedure Check_Controlling_Formals (Typ : Entity_Id; Subp : Entity_Id); 34 -- Check that all controlling parameters of Subp are of type Typ, 35 -- that defaults for controlling parameters are tag-indeterminate, 36 -- and that the nominal subtype of the parameters and result 37 -- statically match the first subtype of the controlling type. 38 39 procedure Check_Dispatching_Call (N : Node_Id); 40 -- Check if a call is a dispatching call. The subprogram is known to 41 -- be a dispatching operation. The call is dispatching if all the 42 -- controlling actuals are dynamically tagged. This procedure is called 43 -- after overload resolution, so the call is known to be unambiguous. 44 45 procedure Check_Dispatching_Operation (Subp, Old_Subp : Entity_Id); 46 -- Add "Subp" to the list of primitive operations of the corresponding type 47 -- if it has a parameter of this type and is defined at a proper place for 48 -- primitive operations (new primitives are only defined in package spec, 49 -- overridden operation can be defined in any scope). If Old_Subp is not 50 -- Empty we are in the overriding case. 51 52 procedure Check_Operation_From_Incomplete_Type 53 (Subp : Entity_Id; 54 Typ : Entity_Id); 55 -- If a primitive operation was defined for the incomplete view of the 56 -- type, and the full type declaration is a derived type definition, 57 -- the operation may override an inherited one. 58 59 procedure Check_Operation_From_Private_View (Subp, Old_Subp : Entity_Id); 60 -- Add "Old_Subp" to the list of primitive operations of the corresponding 61 -- tagged type if it is the full view of a private tagged type. The Alias 62 -- of "OldSubp" is adjusted to point to the inherited procedure of the 63 -- full view because it is always this one which has to be called. 64 65 function Find_Controlling_Arg (N : Node_Id) return Node_Id; 66 -- Returns the actual controlling argument if N is dynamically tagged, 67 -- and Empty if it is not dynamically tagged. 68 69 function Find_Dispatching_Type (Subp : Entity_Id) return Entity_Id; 70 -- Check whether a subprogram is dispatching, and find the tagged 71 -- type of the controlling argument or arguments. 72 73 function Is_Dynamically_Tagged (N : Node_Id) return Boolean; 74 -- Used to determine whether a call is dispatching, i.e. if is an 75 -- an expression of a class_Wide type, or a call to a function with 76 -- controlling result where at least one operand is dynamically tagged. 77 78 function Is_Tag_Indeterminate (N : Node_Id) return Boolean; 79 -- An expression is tag-indeterminate if it is a call that dispatches 80 -- on result, and all controlling operands are also indeterminate. 81 -- Such a function call may inherit a tag from an enclosing call. 82 83 procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id); 84 -- If a function call is tag-indeterminate, its controlling argument is 85 -- found in the context; either an enclosing call, or the left-hand side 86 -- of the enclosing assignment statement. The tag must be propagated 87 -- recursively to the tag-indeterminate actuals of the call. 88 89end Sem_Disp; 90