-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2015, 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- --
package Sem_Disp is
procedure Check_Controlling_Formals (Typ : Entity_Id; Subp : Entity_Id);
- -- Check that all controlling parameters of Subp are of type Typ,
- -- that defaults for controlling parameters are tag-indeterminate,
- -- and that the nominal subtype of the parameters and result
- -- statically match the first subtype of the controlling type.
+ -- Check that all controlling parameters of Subp are of type Typ, that
+ -- defaults for controlling parameters are tag-indeterminate, and that the
+ -- nominal subtype of the parameters and result statically match the first
+ -- subtype of the controlling type. Issues appropriate error messages if
+ -- any of these requirements is not met.
procedure Check_Dispatching_Call (N : Node_Id);
- -- Check if a call is a dispatching call. The subprogram is known to
- -- be a dispatching operation. The call is dispatching if all the
- -- controlling actuals are dynamically tagged. This procedure is called
- -- after overload resolution, so the call is known to be unambiguous.
+ -- Check if the call N is a dispatching call. The subprogram is known to be
+ -- a dispatching operation. The call is dispatching if all the controlling
+ -- actuals are dynamically tagged. This procedure is called after overload
+ -- resolution, so the call is known to be unambiguous.
procedure Check_Dispatching_Operation (Subp, Old_Subp : Entity_Id);
- -- Add "Subp" to the list of primitive operations of the corresponding type
+ -- Add Subp to the list of primitive operations of the corresponding type
-- if it has a parameter of this type and is defined at a proper place for
-- primitive operations (new primitives are only defined in package spec,
-- overridden operation can be defined in any scope). If Old_Subp is not
-- Empty we are in the overriding case. If the tagged type associated with
-- Subp is a concurrent type (case that occurs when the type is declared in
-- a generic because the analysis of generics disables generation of the
- -- corresponding record) then this routine does does not add "Subp" to the
+ -- corresponding record) then this routine does does not add Subp to the
-- list of primitive operations but leaves Subp decorated as dispatching
-- operation to enable checks associated with the Object.Operation notation
-- If a primitive operation was defined for the incomplete view of the
-- type, and the full type declaration is a derived type definition,
-- the operation may override an inherited one.
+ -- Need more description here, what are the parameters, and what does
+ -- this call actually do???
procedure Check_Operation_From_Private_View (Subp, Old_Subp : Entity_Id);
- -- Add "Old_Subp" to the list of primitive operations of the corresponding
+ -- Add Old_Subp to the list of primitive operations of the corresponding
-- tagged type if it is the full view of a private tagged type. The Alias
- -- of "OldSubp" is adjusted to point to the inherited procedure of the
+ -- of Old_Subp is adjusted to point to the inherited procedure of the
-- full view because it is always this one which has to be called.
+ -- What is Subp used for???
function Covers_Some_Interface (Prim : Entity_Id) return Boolean;
-- Returns true if Prim covers some interface primitive of its associated
-- is invoked.
function Find_Controlling_Arg (N : Node_Id) return Node_Id;
- -- Returns the actual controlling argument if N is dynamically tagged,
- -- and Empty if it is not dynamically tagged.
+ -- Returns the actual controlling argument if N is dynamically tagged, and
+ -- Empty if it is not dynamically tagged.
function Find_Dispatching_Type (Subp : Entity_Id) return Entity_Id;
- -- Check whether a subprogram is dispatching, and find the tagged type of
- -- the controlling argument or arguments. Returns Empty if Subp is not a
- -- dispatching operation.
+ -- Check whether the subprogram Subp is dispatching, and find the tagged
+ -- type of the controlling argument or arguments. Returns Empty if Subp
+ -- is not a dispatching operation.
function Find_Primitive_Covering_Interface
(Tagged_Type : Entity_Id;
Iface_Prim : Entity_Id) return Entity_Id;
- -- Search in the homonym chain for the primitive of Tagged_Type that covers
+ -- Search the homonym chain for the primitive of Tagged_Type that covers
-- Iface_Prim. The homonym chain traversal is required to catch primitives
-- associated with the partial view of private types when processing the
- -- corresponding full view. If the entity is not found then search for it
+ -- corresponding full view. If the entity is not found, then search for it
-- in the list of primitives of Tagged_Type. This latter search is needed
-- when the interface primitive is covered by a private subprogram. If the
-- primitive has not been covered yet then return the entity that will be
-- and Interfaces_Only should be True.
function Is_Dynamically_Tagged (N : Node_Id) return Boolean;
- -- Used to determine whether a call is dispatching, i.e. if is an
+ -- Used to determine whether a call is dispatching, i.e. if it is
-- an expression of a class_Wide type, or a call to a function with
-- controlling result where at least one operand is dynamically tagged.
+ -- Also used to determine whether an entity has a class-wide type, or a
+ -- function call that dispatches on the result. Used to verify that all the
+ -- dependent expressions in a conditional expression are equally tagged.
function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean;
-- Returns True if E is a null procedure that is an interface primitive
function Is_Tag_Indeterminate (N : Node_Id) return Boolean;
- -- An expression is tag-indeterminate if it is a call that dispatches
- -- on result, and all controlling operands are also indeterminate.
- -- Such a function call may inherit a tag from an enclosing call.
+ -- Returns true if the expression N is tag-indeterminate. An expression
+ -- is tag-indeterminate if it is a call that dispatches on result, and all
+ -- controlling operands are also indeterminate. Such a function call may
+ -- inherit a tag from an enclosing call.
procedure Override_Dispatching_Operation
(Tagged_Type : Entity_Id;
Prev_Op : Entity_Id;
New_Op : Entity_Id;
Is_Wrapper : Boolean := False);
- -- Replace an implicit dispatching operation with an explicit one.
- -- Prev_Op is an inherited primitive operation which is overridden
- -- by the explicit declaration of New_Op. Is_Wrapper is True when
- -- New_Op is an internally generated wrapper of a controlling function.
+ -- Replace an implicit dispatching operation of the type Tagged_Type
+ -- with an explicit one. Prev_Op is an inherited primitive operation which
+ -- is overridden by the explicit declaration of New_Op. Is_Wrapper is
+ -- True when New_Op is an internally generated wrapper of a controlling
+ -- function. The caller checks that Tagged_Type is indeed a tagged type.
procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id);
- -- If a function call is tag-indeterminate, its controlling argument is
- -- found in the context; either an enclosing call, or the left-hand side
+ -- If a function call is tag-indeterminate, its controlling argument is
+ -- found in the context: either an enclosing call, or the left-hand side
-- of the enclosing assignment statement. The tag must be propagated
-- recursively to the tag-indeterminate actuals of the call.
+ -- Need clear description of the parameters Control and Actual, especially
+ -- since the comments above refer to actuals in the plural ???
end Sem_Disp;
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