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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ A T T R --
-- --
-- B o d y --
-- --
-- $Revision: 1.7 $
-- --
-- Copyright (C) 1992-2001, 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. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
with Atree; use Atree;
with Checks; use Checks;
with Einfo; use Einfo;
with Errout; use Errout;
with Eval_Fat;
with Exp_Tss; use Exp_Tss;
with Exp_Util; use Exp_Util;
with Expander; use Expander;
with Freeze; use Freeze;
with Lib.Xref; use Lib.Xref;
with Namet; use Namet;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Restrict; use Restrict;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Cat; use Sem_Cat;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
with Sem_Ch13; use Sem_Ch13;
with Sem_Dist; use Sem_Dist;
with Sem_Eval; use Sem_Eval;
with Sem_Res; use Sem_Res;
with Sem_Type; use Sem_Type;
with Sem_Util; use Sem_Util;
with Stand; use Stand;
with Sinfo; use Sinfo;
with Sinput; use Sinput;
with Snames; use Snames;
with Stand;
with Stringt; use Stringt;
with Targparm; use Targparm;
with Ttypes; use Ttypes;
with Ttypef; use Ttypef;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Urealp; use Urealp;
with Widechar; use Widechar;
package body Sem_Attr is
True_Value : constant Uint := Uint_1;
False_Value : constant Uint := Uint_0;
-- Synonyms to be used when these constants are used as Boolean values
Bad_Attribute : exception;
-- Exception raised if an error is detected during attribute processing,
-- used so that we can abandon the processing so we don't run into
-- trouble with cascaded errors.
-- The following array is the list of attributes defined in the Ada 83 RM
Attribute_83 : Attribute_Class_Array := Attribute_Class_Array'(
Attribute_Address |
Attribute_Aft |
Attribute_Alignment |
Attribute_Base |
Attribute_Callable |
Attribute_Constrained |
Attribute_Count |
Attribute_Delta |
Attribute_Digits |
Attribute_Emax |
Attribute_Epsilon |
Attribute_First |
Attribute_First_Bit |
Attribute_Fore |
Attribute_Image |
Attribute_Large |
Attribute_Last |
Attribute_Last_Bit |
Attribute_Leading_Part |
Attribute_Length |
Attribute_Machine_Emax |
Attribute_Machine_Emin |
Attribute_Machine_Mantissa |
Attribute_Machine_Overflows |
Attribute_Machine_Radix |
Attribute_Machine_Rounds |
Attribute_Mantissa |
Attribute_Pos |
Attribute_Position |
Attribute_Pred |
Attribute_Range |
Attribute_Safe_Emax |
Attribute_Safe_Large |
Attribute_Safe_Small |
Attribute_Size |
Attribute_Small |
Attribute_Storage_Size |
Attribute_Succ |
Attribute_Terminated |
Attribute_Val |
Attribute_Value |
Attribute_Width => True,
others => False);
-----------------------
-- Local_Subprograms --
-----------------------
procedure Eval_Attribute (N : Node_Id);
-- Performs compile time evaluation of attributes where possible, leaving
-- the Is_Static_Expression/Raises_Constraint_Error flags appropriately
-- set, and replacing the node with a literal node if the value can be
-- computed at compile time. All static attribute references are folded,
-- as well as a number of cases of non-static attributes that can always
-- be computed at compile time (e.g. floating-point model attributes that
-- are applied to non-static subtypes). Of course in such cases, the
-- Is_Static_Expression flag will not be set on the resulting literal.
-- Note that the only required action of this procedure is to catch the
-- static expression cases as described in the RM. Folding of other cases
-- is done where convenient, but some additional non-static folding is in
-- N_Expand_Attribute_Reference in cases where this is more convenient.
function Is_Anonymous_Tagged_Base
(Anon : Entity_Id;
Typ : Entity_Id)
return Boolean;
-- For derived tagged types that constrain parent discriminants we build
-- an anonymous unconstrained base type. We need to recognize the relation
-- between the two when analyzing an access attribute for a constrained
-- component, before the full declaration for Typ has been analyzed, and
-- where therefore the prefix of the attribute does not match the enclosing
-- scope.
-----------------------
-- Analyze_Attribute --
-----------------------
procedure Analyze_Attribute (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Aname : constant Name_Id := Attribute_Name (N);
P : constant Node_Id := Prefix (N);
Exprs : constant List_Id := Expressions (N);
Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
E1 : Node_Id;
E2 : Node_Id;
P_Type : Entity_Id;
-- Type of prefix after analysis
P_Base_Type : Entity_Id;
-- Base type of prefix after analysis
P_Root_Type : Entity_Id;
-- Root type of prefix after analysis
Unanalyzed : Node_Id;
-----------------------
-- Local Subprograms --
-----------------------
procedure Access_Attribute;
-- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
-- Internally, Id distinguishes which of the three cases is involved.
procedure Check_Array_Or_Scalar_Type;
-- Common procedure used by First, Last, Range attribute to check
-- that the prefix is a constrained array or scalar type, or a name
-- of an array object, and that an argument appears only if appropriate
-- (i.e. only in the array case).
procedure Check_Array_Type;
-- Common semantic checks for all array attributes. Checks that the
-- prefix is a constrained array type or the name of an array object.
-- The error message for non-arrays is specialized appropriately.
procedure Check_Asm_Attribute;
-- Common semantic checks for Asm_Input and Asm_Output attributes
procedure Check_Component;
-- Common processing for Bit_Position, First_Bit, Last_Bit, and
-- Position. Checks prefix is an appropriate selected component.
procedure Check_Decimal_Fixed_Point_Type;
-- Check that prefix of attribute N is a decimal fixed-point type
procedure Check_Dereference;
-- If the prefix of attribute is an object of an access type, then
-- introduce an explicit deference, and adjust P_Type accordingly.
procedure Check_Discrete_Type;
-- Verify that prefix of attribute N is a discrete type
procedure Check_E0;
-- Check that no attribute arguments are present
procedure Check_Either_E0_Or_E1;
-- Check that there are zero or one attribute arguments present
procedure Check_E1;
-- Check that exactly one attribute argument is present
procedure Check_E2;
-- Check that two attribute arguments are present
procedure Check_Enum_Image;
-- If the prefix type is an enumeration type, set all its literals
-- as referenced, since the image function could possibly end up
-- referencing any of the literals indirectly.
procedure Check_Enumeration_Type;
-- Verify that prefix of attribute N is an enumeration type
procedure Check_Fixed_Point_Type;
-- Verify that prefix of attribute N is a fixed type
procedure Check_Fixed_Point_Type_0;
-- Verify that prefix of attribute N is a fixed type and that
-- no attribute expressions are present
procedure Check_Floating_Point_Type;
-- Verify that prefix of attribute N is a float type
procedure Check_Floating_Point_Type_0;
-- Verify that prefix of attribute N is a float type and that
-- no attribute expressions are present
procedure Check_Floating_Point_Type_1;
-- Verify that prefix of attribute N is a float type and that
-- exactly one attribute expression is present
procedure Check_Floating_Point_Type_2;
-- Verify that prefix of attribute N is a float type and that
-- two attribute expressions are present
procedure Legal_Formal_Attribute;
-- Common processing for attributes Definite, and Has_Discriminants
procedure Check_Integer_Type;
-- Verify that prefix of attribute N is an integer type
procedure Check_Library_Unit;
-- Verify that prefix of attribute N is a library unit
procedure Check_Not_Incomplete_Type;
-- Check that P (the prefix of the attribute) is not an incomplete
-- type or a private type for which no full view has been given.
procedure Check_Object_Reference (P : Node_Id);
-- Check that P (the prefix of the attribute) is an object reference
procedure Check_Program_Unit;
-- Verify that prefix of attribute N is a program unit
procedure Check_Real_Type;
-- Verify that prefix of attribute N is fixed or float type
procedure Check_Scalar_Type;
-- Verify that prefix of attribute N is a scalar type
procedure Check_Standard_Prefix;
-- Verify that prefix of attribute N is package Standard
procedure Check_Stream_Attribute (Nam : Name_Id);
-- Validity checking for stream attribute. Nam is the name of the
-- corresponding possible defined attribute function (e.g. for the
-- Read attribute, Nam will be Name_uRead).
procedure Check_Task_Prefix;
-- Verify that prefix of attribute N is a task or task type
procedure Check_Type;
-- Verify that the prefix of attribute N is a type
procedure Check_Unit_Name (Nod : Node_Id);
-- Check that Nod is of the form of a library unit name, i.e that
-- it is an identifier, or a selected component whose prefix is
-- itself of the form of a library unit name. Note that this is
-- quite different from Check_Program_Unit, since it only checks
-- the syntactic form of the name, not the semantic identity. This
-- is because it is used with attributes (Elab_Body, Elab_Spec, and
-- UET_Address) which can refer to non-visible unit.
procedure Error_Attr (Msg : String; Error_Node : Node_Id);
pragma No_Return (Error_Attr);
-- Posts error using Error_Msg_N at given node, sets type of attribute
-- node to Any_Type, and then raises Bad_Attribute to avoid any further
-- semantic processing. The message typically contains a % insertion
-- character which is replaced by the attribute name.
procedure Standard_Attribute (Val : Int);
-- Used to process attributes whose prefix is package Standard which
-- yield values of type Universal_Integer. The attribute reference
-- node is rewritten with an integer literal of the given value.
procedure Unexpected_Argument (En : Node_Id);
-- Signal unexpected attribute argument (En is the argument)
procedure Validate_Non_Static_Attribute_Function_Call;
-- Called when processing an attribute that is a function call to a
-- non-static function, i.e. an attribute function that either takes
-- non-scalar arguments or returns a non-scalar result. Verifies that
-- such a call does not appear in a preelaborable context.
----------------------
-- Access_Attribute --
----------------------
procedure Access_Attribute is
Acc_Type : Entity_Id;
Scop : Entity_Id;
Typ : Entity_Id;
function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id;
-- Build an access-to-object type whose designated type is DT,
-- and whose Ekind is appropriate to the attribute type. The
-- type that is constructed is returned as the result.
procedure Build_Access_Subprogram_Type (P : Node_Id);
-- Build an access to subprogram whose designated type is
-- the type of the prefix. If prefix is overloaded, so it the
-- node itself. The result is stored in Acc_Type.
------------------------------
-- Build_Access_Object_Type --
------------------------------
function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
Typ : Entity_Id;
begin
if Aname = Name_Unrestricted_Access then
Typ :=
New_Internal_Entity
(E_Allocator_Type, Current_Scope, Loc, 'A');
else
Typ :=
New_Internal_Entity
(E_Access_Attribute_Type, Current_Scope, Loc, 'A');
end if;
Set_Etype (Typ, Typ);
Init_Size_Align (Typ);
Set_Is_Itype (Typ);
Set_Associated_Node_For_Itype (Typ, N);
Set_Directly_Designated_Type (Typ, DT);
return Typ;
end Build_Access_Object_Type;
----------------------------------
-- Build_Access_Subprogram_Type --
----------------------------------
procedure Build_Access_Subprogram_Type (P : Node_Id) is
Index : Interp_Index;
It : Interp;
function Get_Kind (E : Entity_Id) return Entity_Kind;
-- Distinguish between access to regular and protected
-- subprograms.
function Get_Kind (E : Entity_Id) return Entity_Kind is
begin
if Convention (E) = Convention_Protected then
return E_Access_Protected_Subprogram_Type;
else
return E_Access_Subprogram_Type;
end if;
end Get_Kind;
-- Start of processing for Build_Access_Subprogram_Type
begin
if not Is_Overloaded (P) then
Acc_Type :=
New_Internal_Entity
(Get_Kind (Entity (P)), Current_Scope, Loc, 'A');
Set_Etype (Acc_Type, Acc_Type);
Set_Directly_Designated_Type (Acc_Type, Entity (P));
Set_Etype (N, Acc_Type);
else
Get_First_Interp (P, Index, It);
Set_Etype (N, Any_Type);
while Present (It.Nam) loop
if not Is_Intrinsic_Subprogram (It.Nam) then
Acc_Type :=
New_Internal_Entity
(Get_Kind (It.Nam), Current_Scope, Loc, 'A');
Set_Etype (Acc_Type, Acc_Type);
Set_Directly_Designated_Type (Acc_Type, It.Nam);
Add_One_Interp (N, Acc_Type, Acc_Type);
end if;
Get_Next_Interp (Index, It);
end loop;
if Etype (N) = Any_Type then
Error_Attr ("prefix of % attribute cannot be intrinsic", P);
end if;
end if;
end Build_Access_Subprogram_Type;
-- Start of processing for Access_Attribute
begin
Check_E0;
if Nkind (P) = N_Character_Literal then
Error_Attr
("prefix of % attribute cannot be enumeration literal", P);
-- In the case of an access to subprogram, use the name of the
-- subprogram itself as the designated type. Type-checking in
-- this case compares the signatures of the designated types.
elsif Is_Entity_Name (P)
and then Is_Overloadable (Entity (P))
then
Build_Access_Subprogram_Type (P);
return;
-- Component is an operation of a protected type.
elsif (Nkind (P) = N_Selected_Component
and then Is_Overloadable (Entity (Selector_Name (P))))
then
if Ekind (Entity (Selector_Name (P))) = E_Entry then
Error_Attr ("Prefix of % attribute must be subprogram", P);
end if;
Build_Access_Subprogram_Type (Selector_Name (P));
return;
end if;
-- Deal with incorrect reference to a type, but note that some
-- accesses are allowed (references to the current type instance).
if Is_Entity_Name (P) then
Scop := Current_Scope;
Typ := Entity (P);
if Is_Type (Typ) then
-- OK if we are within the scope of a limited type
-- let's mark the component as having per object constraint
if Is_Anonymous_Tagged_Base (Scop, Typ) then
Typ := Scop;
Set_Entity (P, Typ);
Set_Etype (P, Typ);
end if;
if Typ = Scop then
declare
Q : Node_Id := Parent (N);
begin
while Present (Q)
and then Nkind (Q) /= N_Component_Declaration
loop
Q := Parent (Q);
end loop;
if Present (Q) then
Set_Has_Per_Object_Constraint (
Defining_Identifier (Q), True);
end if;
end;
if Nkind (P) = N_Expanded_Name then
Error_Msg_N
("current instance prefix must be a direct name", P);
end if;
-- If a current instance attribute appears within a
-- a component constraint it must appear alone; other
-- contexts (default expressions, within a task body)
-- are not subject to this restriction.
if not In_Default_Expression
and then not Has_Completion (Scop)
and then
Nkind (Parent (N)) /= N_Discriminant_Association
and then
Nkind (Parent (N)) /= N_Index_Or_Discriminant_Constraint
then
Error_Msg_N
("current instance attribute must appear alone", N);
end if;
-- OK if we are in initialization procedure for the type
-- in question, in which case the reference to the type
-- is rewritten as a reference to the current object.
elsif Ekind (Scop) = E_Procedure
and then Chars (Scop) = Name_uInit_Proc
and then Etype (First_Formal (Scop)) = Typ
then
Rewrite (N,
Make_Attribute_Reference (Loc,
Prefix => Make_Identifier (Loc, Name_uInit),
Attribute_Name => Name_Unrestricted_Access));
Analyze (N);
return;
-- OK if a task type, this test needs sharpening up ???
elsif Is_Task_Type (Typ) then
null;
-- Otherwise we have an error case
else
Error_Attr ("% attribute cannot be applied to type", P);
return;
end if;
end if;
end if;
-- If we fall through, we have a normal access to object case.
-- Unrestricted_Access is legal wherever an allocator would be
-- legal, so its Etype is set to E_Allocator. The expected type
-- of the other attributes is a general access type, and therefore
-- we label them with E_Access_Attribute_Type.
if not Is_Overloaded (P) then
Acc_Type := Build_Access_Object_Type (P_Type);
Set_Etype (N, Acc_Type);
else
declare
Index : Interp_Index;
It : Interp;
begin
Set_Etype (N, Any_Type);
Get_First_Interp (P, Index, It);
while Present (It.Typ) loop
Acc_Type := Build_Access_Object_Type (It.Typ);
Add_One_Interp (N, Acc_Type, Acc_Type);
Get_Next_Interp (Index, It);
end loop;
end;
end if;
-- Check for aliased view unless unrestricted case. We allow
-- a nonaliased prefix when within an instance because the
-- prefix may have been a tagged formal object, which is
-- defined to be aliased even when the actual might not be
-- (other instance cases will have been caught in the generic).
if Aname /= Name_Unrestricted_Access
and then not Is_Aliased_View (P)
and then not In_Instance
then
Error_Attr ("prefix of % attribute must be aliased", P);
end if;
end Access_Attribute;
--------------------------------
-- Check_Array_Or_Scalar_Type --
--------------------------------
procedure Check_Array_Or_Scalar_Type is
Index : Entity_Id;
D : Int;
-- Dimension number for array attributes.
begin
-- Case of string literal or string literal subtype. These cases
-- cannot arise from legal Ada code, but the expander is allowed
-- to generate them. They require special handling because string
-- literal subtypes do not have standard bounds (the whole idea
-- of these subtypes is to avoid having to generate the bounds)
if Ekind (P_Type) = E_String_Literal_Subtype then
Set_Etype (N, Etype (First_Index (P_Base_Type)));
return;
-- Scalar types
elsif Is_Scalar_Type (P_Type) then
Check_Type;
if Present (E1) then
Error_Attr ("invalid argument in % attribute", E1);
else
Set_Etype (N, P_Base_Type);
return;
end if;
-- The following is a special test to allow 'First to apply to
-- private scalar types if the attribute comes from generated
-- code. This occurs in the case of Normalize_Scalars code.
elsif Is_Private_Type (P_Type)
and then Present (Full_View (P_Type))
and then Is_Scalar_Type (Full_View (P_Type))
and then not Comes_From_Source (N)
then
Set_Etype (N, Implementation_Base_Type (P_Type));
-- Array types other than string literal subtypes handled above
else
Check_Array_Type;
-- We know prefix is an array type, or the name of an array
-- object, and that the expression, if present, is static
-- and within the range of the dimensions of the type.
if Is_Array_Type (P_Type) then
Index := First_Index (P_Base_Type);
else pragma Assert (Is_Access_Type (P_Type));
Index := First_Index (Base_Type (Designated_Type (P_Type)));
end if;
if No (E1) then
-- First dimension assumed
Set_Etype (N, Base_Type (Etype (Index)));
else
D := UI_To_Int (Intval (E1));
for J in 1 .. D - 1 loop
Next_Index (Index);
end loop;
Set_Etype (N, Base_Type (Etype (Index)));
Set_Etype (E1, Standard_Integer);
end if;
end if;
end Check_Array_Or_Scalar_Type;
----------------------
-- Check_Array_Type --
----------------------
procedure Check_Array_Type is
D : Int;
-- Dimension number for array attributes.
begin
-- If the type is a string literal type, then this must be generated
-- internally, and no further check is required on its legality.
if Ekind (P_Type) = E_String_Literal_Subtype then
return;
-- If the type is a composite, it is an illegal aggregate, no point
-- in going on.
elsif P_Type = Any_Composite then
raise Bad_Attribute;
end if;
-- Normal case of array type or subtype
Check_Either_E0_Or_E1;
if Is_Array_Type (P_Type) then
if not Is_Constrained (P_Type)
and then Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
-- Note: we do not call Error_Attr here, since we prefer to
-- continue, using the relevant index type of the array,
-- even though it is unconstrained. This gives better error
-- recovery behavior.
Error_Msg_Name_1 := Aname;
Error_Msg_N
("prefix for % attribute must be constrained array", P);
end if;
D := Number_Dimensions (P_Type);
elsif Is_Access_Type (P_Type)
and then Is_Array_Type (Designated_Type (P_Type))
then
if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
Error_Attr ("prefix of % attribute cannot be access type", P);
end if;
D := Number_Dimensions (Designated_Type (P_Type));
-- If there is an implicit dereference, then we must freeze
-- the designated type of the access type, since the type of
-- the referenced array is this type (see AI95-00106).
Freeze_Before (N, Designated_Type (P_Type));
else
if Is_Private_Type (P_Type) then
Error_Attr
("prefix for % attribute may not be private type", P);
elsif Attr_Id = Attribute_First
or else
Attr_Id = Attribute_Last
then
Error_Attr ("invalid prefix for % attribute", P);
else
Error_Attr ("prefix for % attribute must be array", P);
end if;
end if;
if Present (E1) then
Resolve (E1, Any_Integer);
Set_Etype (E1, Standard_Integer);
if not Is_Static_Expression (E1)
or else Raises_Constraint_Error (E1)
then
Error_Attr ("expression for dimension must be static", E1);
elsif UI_To_Int (Expr_Value (E1)) > D
or else UI_To_Int (Expr_Value (E1)) < 1
then
Error_Attr ("invalid dimension number for array type", E1);
end if;
end if;
end Check_Array_Type;
-------------------------
-- Check_Asm_Attribute --
-------------------------
procedure Check_Asm_Attribute is
begin
Check_Type;
Check_E2;
-- Check first argument is static string expression
Analyze_And_Resolve (E1, Standard_String);
if Etype (E1) = Any_Type then
return;
elsif not Is_OK_Static_Expression (E1) then
Error_Attr
("constraint argument must be static string expression", E1);
end if;
-- Check second argument is right type
Analyze_And_Resolve (E2, Entity (P));
-- Note: that is all we need to do, we don't need to check
-- that it appears in a correct context. The Ada type system
-- will do that for us.
end Check_Asm_Attribute;
---------------------
-- Check_Component --
---------------------
procedure Check_Component is
begin
Check_E0;
if Nkind (P) /= N_Selected_Component
or else
(Ekind (Entity (Selector_Name (P))) /= E_Component
and then
Ekind (Entity (Selector_Name (P))) /= E_Discriminant)
then
Error_Attr
("prefix for % attribute must be selected component", P);
end if;
end Check_Component;
------------------------------------
-- Check_Decimal_Fixed_Point_Type --
------------------------------------
procedure Check_Decimal_Fixed_Point_Type is
begin
Check_Type;
if not Is_Decimal_Fixed_Point_Type (P_Type) then
Error_Attr
("prefix of % attribute must be decimal type", P);
end if;
end Check_Decimal_Fixed_Point_Type;
-----------------------
-- Check_Dereference --
-----------------------
procedure Check_Dereference is
begin
if Is_Object_Reference (P)
and then Is_Access_Type (P_Type)
then
Rewrite (P,
Make_Explicit_Dereference (Sloc (P),
Prefix => Relocate_Node (P)));
Analyze_And_Resolve (P);
P_Type := Etype (P);
if P_Type = Any_Type then
raise Bad_Attribute;
end if;
P_Base_Type := Base_Type (P_Type);
P_Root_Type := Root_Type (P_Base_Type);
end if;
end Check_Dereference;
-------------------------
-- Check_Discrete_Type --
-------------------------
procedure Check_Discrete_Type is
begin
Check_Type;
if not Is_Discrete_Type (P_Type) then
Error_Attr ("prefix of % attribute must be discrete type", P);
end if;
end Check_Discrete_Type;
--------------
-- Check_E0 --
--------------
procedure Check_E0 is
begin
if Present (E1) then
Unexpected_Argument (E1);
end if;
end Check_E0;
--------------
-- Check_E1 --
--------------
procedure Check_E1 is
begin
Check_Either_E0_Or_E1;
if No (E1) then
-- Special-case attributes that are functions and that appear as
-- the prefix of another attribute. Error is posted on parent.
if Nkind (Parent (N)) = N_Attribute_Reference
and then (Attribute_Name (Parent (N)) = Name_Address
or else
Attribute_Name (Parent (N)) = Name_Code_Address
or else
Attribute_Name (Parent (N)) = Name_Access)
then
Error_Msg_Name_1 := Attribute_Name (Parent (N));
Error_Msg_N ("illegal prefix for % attribute", Parent (N));
Set_Etype (Parent (N), Any_Type);
Set_Entity (Parent (N), Any_Type);
raise Bad_Attribute;
else
Error_Attr ("missing argument for % attribute", N);
end if;
end if;
end Check_E1;
--------------
-- Check_E2 --
--------------
procedure Check_E2 is
begin
if No (E1) then
Error_Attr ("missing arguments for % attribute (2 required)", N);
elsif No (E2) then
Error_Attr ("missing argument for % attribute (2 required)", N);
end if;
end Check_E2;
---------------------------
-- Check_Either_E0_Or_E1 --
---------------------------
procedure Check_Either_E0_Or_E1 is
begin
if Present (E2) then
Unexpected_Argument (E2);
end if;
end Check_Either_E0_Or_E1;
----------------------
-- Check_Enum_Image --
----------------------
procedure Check_Enum_Image is
Lit : Entity_Id;
begin
if Is_Enumeration_Type (P_Base_Type) then
Lit := First_Literal (P_Base_Type);
while Present (Lit) loop
Set_Referenced (Lit);
Next_Literal (Lit);
end loop;
end if;
end Check_Enum_Image;
----------------------------
-- Check_Enumeration_Type --
----------------------------
procedure Check_Enumeration_Type is
begin
Check_Type;
if not Is_Enumeration_Type (P_Type) then
Error_Attr ("prefix of % attribute must be enumeration type", P);
end if;
end Check_Enumeration_Type;
----------------------------
-- Check_Fixed_Point_Type --
----------------------------
procedure Check_Fixed_Point_Type is
begin
Check_Type;
if not Is_Fixed_Point_Type (P_Type) then
Error_Attr ("prefix of % attribute must be fixed point type", P);
end if;
end Check_Fixed_Point_Type;
------------------------------
-- Check_Fixed_Point_Type_0 --
------------------------------
procedure Check_Fixed_Point_Type_0 is
begin
Check_Fixed_Point_Type;
Check_E0;
end Check_Fixed_Point_Type_0;
-------------------------------
-- Check_Floating_Point_Type --
-------------------------------
procedure Check_Floating_Point_Type is
begin
Check_Type;
if not Is_Floating_Point_Type (P_Type) then
Error_Attr ("prefix of % attribute must be float type", P);
end if;
end Check_Floating_Point_Type;
---------------------------------
-- Check_Floating_Point_Type_0 --
---------------------------------
procedure Check_Floating_Point_Type_0 is
begin
Check_Floating_Point_Type;
Check_E0;
end Check_Floating_Point_Type_0;
---------------------------------
-- Check_Floating_Point_Type_1 --
---------------------------------
procedure Check_Floating_Point_Type_1 is
begin
Check_Floating_Point_Type;
Check_E1;
end Check_Floating_Point_Type_1;
---------------------------------
-- Check_Floating_Point_Type_2 --
---------------------------------
procedure Check_Floating_Point_Type_2 is
begin
Check_Floating_Point_Type;
Check_E2;
end Check_Floating_Point_Type_2;
------------------------
-- Check_Integer_Type --
------------------------
procedure Check_Integer_Type is
begin
Check_Type;
if not Is_Integer_Type (P_Type) then
Error_Attr ("prefix of % attribute must be integer type", P);
end if;
end Check_Integer_Type;
------------------------
-- Check_Library_Unit --
------------------------
procedure Check_Library_Unit is
begin
if not Is_Compilation_Unit (Entity (P)) then
Error_Attr ("prefix of % attribute must be library unit", P);
end if;
end Check_Library_Unit;
-------------------------------
-- Check_Not_Incomplete_Type --
-------------------------------
procedure Check_Not_Incomplete_Type is
begin
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
or else In_Default_Expression
then
return;
else
Check_Fully_Declared (P_Type, P);
end if;
end Check_Not_Incomplete_Type;
----------------------------
-- Check_Object_Reference --
----------------------------
procedure Check_Object_Reference (P : Node_Id) is
Rtyp : Entity_Id;
begin
-- If we need an object, and we have a prefix that is the name of
-- a function entity, convert it into a function call.
if Is_Entity_Name (P)
and then Ekind (Entity (P)) = E_Function
then
Rtyp := Etype (Entity (P));
Rewrite (P,
Make_Function_Call (Sloc (P),
Name => Relocate_Node (P)));
Analyze_And_Resolve (P, Rtyp);
-- Otherwise we must have an object reference
elsif not Is_Object_Reference (P) then
Error_Attr ("prefix of % attribute must be object", P);
end if;
end Check_Object_Reference;
------------------------
-- Check_Program_Unit --
------------------------
procedure Check_Program_Unit is
begin
if Is_Entity_Name (P) then
declare
K : constant Entity_Kind := Ekind (Entity (P));
T : constant Entity_Id := Etype (Entity (P));
begin
if K in Subprogram_Kind
or else K in Task_Kind
or else K in Protected_Kind
or else K = E_Package
or else K in Generic_Unit_Kind
or else (K = E_Variable
and then
(Is_Task_Type (T)
or else
Is_Protected_Type (T)))
then
return;
end if;
end;
end if;
Error_Attr ("prefix of % attribute must be program unit", P);
end Check_Program_Unit;
---------------------
-- Check_Real_Type --
---------------------
procedure Check_Real_Type is
begin
Check_Type;
if not Is_Real_Type (P_Type) then
Error_Attr ("prefix of % attribute must be real type", P);
end if;
end Check_Real_Type;
-----------------------
-- Check_Scalar_Type --
-----------------------
procedure Check_Scalar_Type is
begin
Check_Type;
if not Is_Scalar_Type (P_Type) then
Error_Attr ("prefix of % attribute must be scalar type", P);
end if;
end Check_Scalar_Type;
---------------------------
-- Check_Standard_Prefix --
---------------------------
procedure Check_Standard_Prefix is
begin
Check_E0;
if Nkind (P) /= N_Identifier
or else Chars (P) /= Name_Standard
then
Error_Attr ("only allowed prefix for % attribute is Standard", P);
end if;
end Check_Standard_Prefix;
----------------------------
-- Check_Stream_Attribute --
----------------------------
procedure Check_Stream_Attribute (Nam : Name_Id) is
Etyp : Entity_Id;
Btyp : Entity_Id;
begin
Validate_Non_Static_Attribute_Function_Call;
-- With the exception of 'Input, Stream attributes are procedures,
-- and can only appear at the position of procedure calls. We check
-- for this here, before they are rewritten, to give a more precise
-- diagnostic.
if Nam = Name_uInput then
null;
elsif Is_List_Member (N)
and then Nkind (Parent (N)) /= N_Procedure_Call_Statement
and then Nkind (Parent (N)) /= N_Aggregate
then
null;
else
Error_Attr
("invalid context for attribute %, which is a procedure", N);
end if;
Check_Type;
Btyp := Implementation_Base_Type (P_Type);
-- Stream attributes not allowed on limited types unless the
-- special OK_For_Stream flag is set.
if Is_Limited_Type (P_Type)
and then Comes_From_Source (N)
and then not Present (TSS (Btyp, Nam))
and then No (Get_Rep_Pragma (Btyp, Name_Stream_Convert))
then
-- Special case the message if we are compiling the stub version
-- of a remote operation. One error on the type is sufficient.
if (Is_Remote_Types (Current_Scope)
or else Is_Remote_Call_Interface (Current_Scope))
and then not Error_Posted (Btyp)
then
Error_Msg_Node_2 := Current_Scope;
Error_Msg_NE
("limited type& used in& has no stream attributes", P, Btyp);
Set_Error_Posted (Btyp);
elsif not Error_Posted (Btyp) then
Error_Msg_NE
("limited type& has no stream attributes", P, Btyp);
end if;
end if;
-- Here we must check that the first argument is an access type
-- that is compatible with Ada.Streams.Root_Stream_Type'Class.
Analyze_And_Resolve (E1);
Etyp := Etype (E1);
-- Note: the double call to Root_Type here is needed because the
-- root type of a class-wide type is the corresponding type (e.g.
-- X for X'Class, and we really want to go to the root.
if not Is_Access_Type (Etyp)
or else Root_Type (Root_Type (Designated_Type (Etyp))) /=
RTE (RE_Root_Stream_Type)
then
Error_Attr
("expected access to Ada.Streams.Root_Stream_Type''Class", E1);
end if;
-- Check that the second argument is of the right type if there is
-- one (the Input attribute has only one argument so this is skipped)
if Present (E2) then
Analyze (E2);
if Nam = Name_uRead
and then not Is_OK_Variable_For_Out_Formal (E2)
then
Error_Attr
("second argument of % attribute must be a variable", E2);
end if;
Resolve (E2, P_Type);
end if;
end Check_Stream_Attribute;
-----------------------
-- Check_Task_Prefix --
-----------------------
procedure Check_Task_Prefix is
begin
Analyze (P);
if Is_Task_Type (Etype (P))
or else (Is_Access_Type (Etype (P))
and then Is_Task_Type (Designated_Type (Etype (P))))
then
Resolve (P, Etype (P));
else
Error_Attr ("prefix of % attribute must be a task", P);
end if;
end Check_Task_Prefix;
----------------
-- Check_Type --
----------------
-- The possibilities are an entity name denoting a type, or an
-- attribute reference that denotes a type (Base or Class). If
-- the type is incomplete, replace it with its full view.
procedure Check_Type is
begin
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
then
Error_Attr ("prefix of % attribute must be a type", P);
elsif Ekind (Entity (P)) = E_Incomplete_Type
and then Present (Full_View (Entity (P)))
then
P_Type := Full_View (Entity (P));
Set_Entity (P, P_Type);
end if;
end Check_Type;
---------------------
-- Check_Unit_Name --
---------------------
procedure Check_Unit_Name (Nod : Node_Id) is
begin
if Nkind (Nod) = N_Identifier then
return;
elsif Nkind (Nod) = N_Selected_Component then
Check_Unit_Name (Prefix (Nod));
if Nkind (Selector_Name (Nod)) = N_Identifier then
return;
end if;
end if;
Error_Attr ("argument for % attribute must be unit name", P);
end Check_Unit_Name;
----------------
-- Error_Attr --
----------------
procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
begin
Error_Msg_Name_1 := Aname;
Error_Msg_N (Msg, Error_Node);
Set_Etype (N, Any_Type);
Set_Entity (N, Any_Type);
raise Bad_Attribute;
end Error_Attr;
----------------------------
-- Legal_Formal_Attribute --
----------------------------
procedure Legal_Formal_Attribute is
begin
Check_E0;
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
then
Error_Attr (" prefix of % attribute must be generic type", N);
elsif Is_Generic_Actual_Type (Entity (P))
or In_Instance
then
null;
elsif Is_Generic_Type (Entity (P)) then
if not Is_Indefinite_Subtype (Entity (P)) then
Error_Attr
(" prefix of % attribute must be indefinite generic type", N);
end if;
else
Error_Attr
(" prefix of % attribute must be indefinite generic type", N);
end if;
Set_Etype (N, Standard_Boolean);
end Legal_Formal_Attribute;
------------------------
-- Standard_Attribute --
------------------------
procedure Standard_Attribute (Val : Int) is
begin
Check_Standard_Prefix;
Rewrite (N,
Make_Integer_Literal (Loc, Val));
Analyze (N);
end Standard_Attribute;
-------------------------
-- Unexpected Argument --
-------------------------
procedure Unexpected_Argument (En : Node_Id) is
begin
Error_Attr ("unexpected argument for % attribute", En);
end Unexpected_Argument;
-------------------------------------------------
-- Validate_Non_Static_Attribute_Function_Call --
-------------------------------------------------
-- This function should be moved to Sem_Dist ???
procedure Validate_Non_Static_Attribute_Function_Call is
begin
if In_Preelaborated_Unit
and then not In_Subprogram_Or_Concurrent_Unit
then
Error_Msg_N ("non-static function call in preelaborated unit", N);
end if;
end Validate_Non_Static_Attribute_Function_Call;
-----------------------------------------------
-- Start of Processing for Analyze_Attribute --
-----------------------------------------------
begin
-- Immediate return if unrecognized attribute (already diagnosed
-- by parser, so there is nothing more that we need to do)
if not Is_Attribute_Name (Aname) then
raise Bad_Attribute;
end if;
-- Deal with Ada 83 and Features issues
if not Attribute_83 (Attr_Id) then
if Ada_83 and then Comes_From_Source (N) then
Error_Msg_Name_1 := Aname;
Error_Msg_N ("(Ada 83) attribute% is not standard?", N);
end if;
if Attribute_Impl_Def (Attr_Id) then
Check_Restriction (No_Implementation_Attributes, N);
end if;
end if;
-- Remote access to subprogram type access attribute reference needs
-- unanalyzed copy for tree transformation. The analyzed copy is used
-- for its semantic information (whether prefix is a remote subprogram
-- name), the unanalyzed copy is used to construct new subtree rooted
-- with N_aggregate which represents a fat pointer aggregate.
if Aname = Name_Access then
Unanalyzed := Copy_Separate_Tree (N);
end if;
-- Analyze prefix and exit if error in analysis. If the prefix is an
-- incomplete type, use full view if available. A special case is
-- that we never analyze the prefix of an Elab_Body or Elab_Spec
-- or UET_Address attribute.
if Aname /= Name_Elab_Body
and then
Aname /= Name_Elab_Spec
and then
Aname /= Name_UET_Address
then
Analyze (P);
P_Type := Etype (P);
if Is_Entity_Name (P)
and then Present (Entity (P))
and then Is_Type (Entity (P))
and then Ekind (Entity (P)) = E_Incomplete_Type
then
P_Type := Get_Full_View (P_Type);
Set_Entity (P, P_Type);
Set_Etype (P, P_Type);
end if;
if P_Type = Any_Type then
raise Bad_Attribute;
end if;
P_Base_Type := Base_Type (P_Type);
P_Root_Type := Root_Type (P_Base_Type);
end if;
-- Analyze expressions that may be present, exiting if an error occurs
if No (Exprs) then
E1 := Empty;
E2 := Empty;
else
E1 := First (Exprs);
Analyze (E1);
-- Check for missing or bad expression (result of previous error)
if No (E1) or else Etype (E1) = Any_Type then
raise Bad_Attribute;
end if;
E2 := Next (E1);
if Present (E2) then
Analyze (E2);
if Etype (E2) = Any_Type then
raise Bad_Attribute;
end if;
if Present (Next (E2)) then
Unexpected_Argument (Next (E2));
end if;
end if;
end if;
if Is_Overloaded (P)
and then Aname /= Name_Access
and then Aname /= Name_Address
and then Aname /= Name_Code_Address
and then Aname /= Name_Count
and then Aname /= Name_Unchecked_Access
then
Error_Attr ("ambiguous prefix for % attribute", P);
end if;
-- Remaining processing depends on attribute
case Attr_Id is
------------------
-- Abort_Signal --
------------------
when Attribute_Abort_Signal =>
Check_Standard_Prefix;
Rewrite (N,
New_Reference_To (Stand.Abort_Signal, Loc));
Analyze (N);
------------
-- Access --
------------
when Attribute_Access =>
Access_Attribute;
-------------
-- Address --
-------------
when Attribute_Address =>
Check_E0;
-- Check for some junk cases, where we have to allow the address
-- attribute but it does not make much sense, so at least for now
-- just replace with Null_Address.
-- We also do this if the prefix is a reference to the AST_Entry
-- attribute. If expansion is active, the attribute will be
-- replaced by a function call, and address will work fine and
-- get the proper value, but if expansion is not active, then
-- the check here allows proper semantic analysis of the reference.
-- An Address attribute created by expansion is legal even when it
-- applies to other entity-denoting expressions.
if (Is_Entity_Name (P)) then
if Is_Subprogram (Entity (P))
or else Is_Object (Entity (P))
or else Ekind (Entity (P)) = E_Label
then
Set_Address_Taken (Entity (P));
elsif (Is_Concurrent_Type (Etype (Entity (P)))
and then Etype (Entity (P)) = Base_Type (Entity (P)))
or else Ekind (Entity (P)) = E_Package
or else Is_Generic_Unit (Entity (P))
then
Rewrite (N,
New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
else
Error_Attr ("invalid prefix for % attribute", P);
end if;
elsif Nkind (P) = N_Attribute_Reference
and then Attribute_Name (P) = Name_AST_Entry
then
Rewrite (N,
New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
elsif Is_Object_Reference (P) then
null;
elsif Nkind (P) = N_Selected_Component
and then Is_Subprogram (Entity (Selector_Name (P)))
then
null;
elsif not Comes_From_Source (N) then
null;
else
Error_Attr ("invalid prefix for % attribute", P);
end if;
Set_Etype (N, RTE (RE_Address));
------------------
-- Address_Size --
------------------
when Attribute_Address_Size =>
Standard_Attribute (System_Address_Size);
--------------
-- Adjacent --
--------------
when Attribute_Adjacent =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
---------
-- Aft --
---------
when Attribute_Aft =>
Check_Fixed_Point_Type_0;
Set_Etype (N, Universal_Integer);
---------------
-- Alignment --
---------------
when Attribute_Alignment =>
-- Don't we need more checking here, cf Size ???
Check_E0;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
---------------
-- Asm_Input --
---------------
when Attribute_Asm_Input =>
Check_Asm_Attribute;
Set_Etype (N, RTE (RE_Asm_Input_Operand));
----------------
-- Asm_Output --
----------------
when Attribute_Asm_Output =>
Check_Asm_Attribute;
if Etype (E2) = Any_Type then
return;
elsif Aname = Name_Asm_Output then
if not Is_Variable (E2) then
Error_Attr
("second argument for Asm_Output is not variable", E2);
end if;
end if;
Note_Possible_Modification (E2);
Set_Etype (N, RTE (RE_Asm_Output_Operand));
---------------
-- AST_Entry --
---------------
when Attribute_AST_Entry => AST_Entry : declare
Ent : Entity_Id;
Pref : Node_Id;
Ptyp : Entity_Id;
Indexed : Boolean;
-- Indicates if entry family index is present. Note the coding
-- here handles the entry family case, but in fact it cannot be
-- executed currently, because pragma AST_Entry does not permit
-- the specification of an entry family.
procedure Bad_AST_Entry;
-- Signal a bad AST_Entry pragma
function OK_Entry (E : Entity_Id) return Boolean;
-- Checks that E is of an appropriate entity kind for an entry
-- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
-- is set True for the entry family case). In the True case,
-- makes sure that Is_AST_Entry is set on the entry.
procedure Bad_AST_Entry is
begin
Error_Attr ("prefix for % attribute must be task entry", P);
end Bad_AST_Entry;
function OK_Entry (E : Entity_Id) return Boolean is
Result : Boolean;
begin
if Indexed then
Result := (Ekind (E) = E_Entry_Family);
else
Result := (Ekind (E) = E_Entry);
end if;
if Result then
if not Is_AST_Entry (E) then
Error_Msg_Name_2 := Aname;
Error_Attr
("% attribute requires previous % pragma", P);
end if;
end if;
return Result;
end OK_Entry;
-- Start of processing for AST_Entry
begin
Check_VMS (N);
Check_E0;
-- Deal with entry family case
if Nkind (P) = N_Indexed_Component then
Pref := Prefix (P);
Indexed := True;
else
Pref := P;
Indexed := False;
end if;
Ptyp := Etype (Pref);
if Ptyp = Any_Type or else Error_Posted (Pref) then
return;
end if;
-- If the prefix is a selected component whose prefix is of an
-- access type, then introduce an explicit dereference.
if Nkind (Pref) = N_Selected_Component
and then Is_Access_Type (Ptyp)
then
Rewrite (Pref,
Make_Explicit_Dereference (Sloc (Pref),
Relocate_Node (Pref)));
Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
end if;
-- Prefix can be of the form a.b, where a is a task object
-- and b is one of the entries of the corresponding task type.
if Nkind (Pref) = N_Selected_Component
and then OK_Entry (Entity (Selector_Name (Pref)))
and then Is_Object_Reference (Prefix (Pref))
and then Is_Task_Type (Etype (Prefix (Pref)))
then
null;
-- Otherwise the prefix must be an entry of a containing task,
-- or of a variable of the enclosing task type.
else
if Nkind (Pref) = N_Identifier
or else Nkind (Pref) = N_Expanded_Name
then
Ent := Entity (Pref);
if not OK_Entry (Ent)
or else not In_Open_Scopes (Scope (Ent))
then
Bad_AST_Entry;
end if;
else
Bad_AST_Entry;
end if;
end if;
Set_Etype (N, RTE (RE_AST_Handler));
end AST_Entry;
----------
-- Base --
----------
when Attribute_Base => Base : declare
Typ : Entity_Id;
begin
Check_Either_E0_Or_E1;
Find_Type (P);
Typ := Entity (P);
if Sloc (Typ) = Standard_Location
and then Base_Type (Typ) = Typ
and then Warn_On_Redundant_Constructs
then
Error_Msg_NE
("?redudant attribute, & is its own base type", N, Typ);
end if;
Set_Etype (N, Base_Type (Entity (P)));
-- If we have an expression present, then really this is a conversion
-- and the tree must be reformed. Note that this is one of the cases
-- in which we do a replace rather than a rewrite, because the
-- original tree is junk.
if Present (E1) then
Replace (N,
Make_Type_Conversion (Loc,
Subtype_Mark =>
Make_Attribute_Reference (Loc,
Prefix => Prefix (N),
Attribute_Name => Name_Base),
Expression => Relocate_Node (E1)));
-- E1 may be overloaded, and its interpretations preserved.
Save_Interps (E1, Expression (N));
Analyze (N);
-- For other cases, set the proper type as the entity of the
-- attribute reference, and then rewrite the node to be an
-- occurrence of the referenced base type. This way, no one
-- else in the compiler has to worry about the base attribute.
else
Set_Entity (N, Base_Type (Entity (P)));
Rewrite (N,
New_Reference_To (Entity (N), Loc));
Analyze (N);
end if;
end Base;
---------
-- Bit --
---------
when Attribute_Bit => Bit :
begin
Check_E0;
if not Is_Object_Reference (P) then
Error_Attr ("prefix for % attribute must be object", P);
-- What about the access object cases ???
else
null;
end if;
Set_Etype (N, Universal_Integer);
end Bit;
---------------
-- Bit_Order --
---------------
when Attribute_Bit_Order => Bit_Order :
begin
Check_E0;
Check_Type;
if not Is_Record_Type (P_Type) then
Error_Attr ("prefix of % attribute must be record type", P);
end if;
if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then
Rewrite (N,
New_Occurrence_Of (RTE (RE_High_Order_First), Loc));
else
Rewrite (N,
New_Occurrence_Of (RTE (RE_Low_Order_First), Loc));
end if;
Set_Etype (N, RTE (RE_Bit_Order));
Resolve (N, Etype (N));
-- Reset incorrect indication of staticness
Set_Is_Static_Expression (N, False);
end Bit_Order;
------------------
-- Bit_Position --
------------------
-- Note: in generated code, we can have a Bit_Position attribute
-- applied to a (naked) record component (i.e. the prefix is an
-- identifier that references an E_Component or E_Discriminant
-- entity directly, and this is interpreted as expected by Gigi.
-- The following code will not tolerate such usage, but when the
-- expander creates this special case, it marks it as analyzed
-- immediately and sets an appropriate type.
when Attribute_Bit_Position =>
if Comes_From_Source (N) then
Check_Component;
end if;
Set_Etype (N, Universal_Integer);
------------------
-- Body_Version --
------------------
when Attribute_Body_Version =>
Check_E0;
Check_Program_Unit;
Set_Etype (N, RTE (RE_Version_String));
--------------
-- Callable --
--------------
when Attribute_Callable =>
Check_E0;
Set_Etype (N, Standard_Boolean);
Check_Task_Prefix;
------------
-- Caller --
------------
when Attribute_Caller => Caller : declare
Ent : Entity_Id;
S : Entity_Id;
begin
Check_E0;
if Nkind (P) = N_Identifier
or else Nkind (P) = N_Expanded_Name
then
Ent := Entity (P);
if not Is_Entry (Ent) then
Error_Attr ("invalid entry name", N);
end if;
else
Error_Attr ("invalid entry name", N);
return;
end if;
for J in reverse 0 .. Scope_Stack.Last loop
S := Scope_Stack.Table (J).Entity;
if S = Scope (Ent) then
Error_Attr ("Caller must appear in matching accept or body", N);
elsif S = Ent then
exit;
end if;
end loop;
Set_Etype (N, RTE (RO_AT_Task_ID));
end Caller;
-------------
-- Ceiling --
-------------
when Attribute_Ceiling =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
-----------
-- Class --
-----------
when Attribute_Class => Class : declare
begin
Check_Restriction (No_Dispatch, N);
Check_Either_E0_Or_E1;
-- If we have an expression present, then really this is a conversion
-- and the tree must be reformed into a proper conversion. This is a
-- Replace rather than a Rewrite, because the original tree is junk.
-- If expression is overloaded, propagate interpretations to new one.
if Present (E1) then
Replace (N,
Make_Type_Conversion (Loc,
Subtype_Mark =>
Make_Attribute_Reference (Loc,
Prefix => Prefix (N),
Attribute_Name => Name_Class),
Expression => Relocate_Node (E1)));
Save_Interps (E1, Expression (N));
Analyze (N);
-- Otherwise we just need to find the proper type
else
Find_Type (N);
end if;
end Class;
------------------
-- Code_Address --
------------------
when Attribute_Code_Address =>
Check_E0;
if Nkind (P) = N_Attribute_Reference
and then (Attribute_Name (P) = Name_Elab_Body
or else
Attribute_Name (P) = Name_Elab_Spec)
then
null;
elsif not Is_Entity_Name (P)
or else (Ekind (Entity (P)) /= E_Function
and then
Ekind (Entity (P)) /= E_Procedure)
then
Error_Attr ("invalid prefix for % attribute", P);
Set_Address_Taken (Entity (P));
end if;
Set_Etype (N, RTE (RE_Address));
--------------------
-- Component_Size --
--------------------
when Attribute_Component_Size =>
Check_E0;
Set_Etype (N, Universal_Integer);
-- Note: unlike other array attributes, unconstrained arrays are OK
if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then
null;
else
Check_Array_Type;
end if;
-------------
-- Compose --
-------------
when Attribute_Compose =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
Resolve (E2, Any_Integer);
-----------------
-- Constrained --
-----------------
when Attribute_Constrained =>
Check_E0;
Set_Etype (N, Standard_Boolean);
-- Case from RM J.4(2) of constrained applied to private type
if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
-- If we are within an instance, the attribute must be legal
-- because it was valid in the generic unit.
if In_Instance then
return;
-- For sure OK if we have a real private type itself, but must
-- be completed, cannot apply Constrained to incomplete type.
elsif Is_Private_Type (Entity (P)) then
Check_Not_Incomplete_Type;
return;
end if;
else
Check_Object_Reference (P);
-- If N does not come from source, then we allow the
-- the attribute prefix to be of a private type whose
-- full type has discriminants. This occurs in cases
-- involving expanded calls to stream attributes.
if not Comes_From_Source (N) then
P_Type := Underlying_Type (P_Type);
end if;
-- Must have discriminants or be an access type designating
-- a type with discriminants. If it is a classwide type is
-- has unknown discriminants.
if Has_Discriminants (P_Type)
or else Has_Unknown_Discriminants (P_Type)
or else
(Is_Access_Type (P_Type)
and then Has_Discriminants (Designated_Type (P_Type)))
then
return;
-- Also allow an object of a generic type if extensions allowed
-- and allow this for any type at all.
elsif (Is_Generic_Type (P_Type)
or else Is_Generic_Actual_Type (P_Type))
and then Extensions_Allowed
then
return;
end if;
end if;
-- Fall through if bad prefix
Error_Attr
("prefix of % attribute must be object of discriminated type", P);
---------------
-- Copy_Sign --
---------------
when Attribute_Copy_Sign =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
-----------
-- Count --
-----------
when Attribute_Count => Count :
declare
Ent : Entity_Id;
S : Entity_Id;
Tsk : Entity_Id;
begin
Check_E0;
if Nkind (P) = N_Identifier
or else Nkind (P) = N_Expanded_Name
then
Ent := Entity (P);
if Ekind (Ent) /= E_Entry then
Error_Attr ("invalid entry name", N);
end if;
elsif Nkind (P) = N_Indexed_Component then
Ent := Entity (Prefix (P));
if Ekind (Ent) /= E_Entry_Family then
Error_Attr ("invalid entry family name", P);
return;
end if;
else
Error_Attr ("invalid entry name", N);
return;
end if;
for J in reverse 0 .. Scope_Stack.Last loop
S := Scope_Stack.Table (J).Entity;
if S = Scope (Ent) then
if Nkind (P) = N_Expanded_Name then
Tsk := Entity (Prefix (P));
-- The prefix denotes either the task type, or else a
-- single task whose task type is being analyzed.
if (Is_Type (Tsk)
and then Tsk = S)
or else (not Is_Type (Tsk)
and then Etype (Tsk) = S
and then not (Comes_From_Source (S)))
then
null;
else
Error_Msg_N
("Count must apply to entry of current task", N);
end if;
end if;
exit;
elsif Ekind (Scope (Ent)) in Task_Kind
and then Ekind (S) /= E_Loop
and then Ekind (S) /= E_Block
and then Ekind (S) /= E_Entry
and then Ekind (S) /= E_Entry_Family
then
Error_Attr ("Count cannot appear in inner unit", N);
elsif Ekind (Scope (Ent)) = E_Protected_Type
and then not Has_Completion (Scope (Ent))
then
Error_Attr ("attribute % can only be used inside body", N);
end if;
end loop;
if Is_Overloaded (P) then
declare
Index : Interp_Index;
It : Interp;
begin
Get_First_Interp (P, Index, It);
while Present (It.Nam) loop
if It.Nam = Ent then
null;
elsif Scope (It.Nam) = Scope (Ent) then
Error_Attr ("ambiguous entry name", N);
else
-- For now make this into a warning. Will become an
-- error after the 3.15 release.
Error_Msg_N
("ambiguous name, resolved to entry?", N);
Error_Msg_N
("\(this will become an error in a later release)?", N);
end if;
Get_Next_Interp (Index, It);
end loop;
end;
end if;
Set_Etype (N, Universal_Integer);
end Count;
-----------------------
-- Default_Bit_Order --
-----------------------
when Attribute_Default_Bit_Order => Default_Bit_Order :
begin
Check_Standard_Prefix;
Check_E0;
if Bytes_Big_Endian then
Rewrite (N,
Make_Integer_Literal (Loc, False_Value));
else
Rewrite (N,
Make_Integer_Literal (Loc, True_Value));
end if;
Set_Etype (N, Universal_Integer);
Set_Is_Static_Expression (N);
end Default_Bit_Order;
--------------
-- Definite --
--------------
when Attribute_Definite =>
Legal_Formal_Attribute;
-----------
-- Delta --
-----------
when Attribute_Delta =>
Check_Fixed_Point_Type_0;
Set_Etype (N, Universal_Real);
------------
-- Denorm --
------------
when Attribute_Denorm =>
Check_Floating_Point_Type_0;
Set_Etype (N, Standard_Boolean);
------------
-- Digits --
------------
when Attribute_Digits =>
Check_E0;
Check_Type;
if not Is_Floating_Point_Type (P_Type)
and then not Is_Decimal_Fixed_Point_Type (P_Type)
then
Error_Attr
("prefix of % attribute must be float or decimal type", P);
end if;
Set_Etype (N, Universal_Integer);
---------------
-- Elab_Body --
---------------
-- Also handles processing for Elab_Spec
when Attribute_Elab_Body | Attribute_Elab_Spec =>
Check_E0;
Check_Unit_Name (P);
Set_Etype (N, Standard_Void_Type);
-- We have to manually call the expander in this case to get
-- the necessary expansion (normally attributes that return
-- entities are not expanded).
Expand (N);
---------------
-- Elab_Spec --
---------------
-- Shares processing with Elab_Body
----------------
-- Elaborated --
----------------
when Attribute_Elaborated =>
Check_E0;
Check_Library_Unit;
Set_Etype (N, Standard_Boolean);
----------
-- Emax --
----------
when Attribute_Emax =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
--------------
-- Enum_Rep --
--------------
when Attribute_Enum_Rep => Enum_Rep : declare
begin
if Present (E1) then
Check_E1;
Check_Discrete_Type;
Resolve (E1, P_Base_Type);
else
if not Is_Entity_Name (P)
or else (not Is_Object (Entity (P))
and then
Ekind (Entity (P)) /= E_Enumeration_Literal)
then
Error_Attr
("prefix of %attribute must be " &
"discrete type/object or enum literal", P);
end if;
end if;
Set_Etype (N, Universal_Integer);
end Enum_Rep;
-------------
-- Epsilon --
-------------
when Attribute_Epsilon =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Real);
--------------
-- Exponent --
--------------
when Attribute_Exponent =>
Check_Floating_Point_Type_1;
Set_Etype (N, Universal_Integer);
Resolve (E1, P_Base_Type);
------------------
-- External_Tag --
------------------
when Attribute_External_Tag =>
Check_E0;
Check_Type;
Set_Etype (N, Standard_String);
if not Is_Tagged_Type (P_Type) then
Error_Attr ("prefix of % attribute must be tagged", P);
end if;
-----------
-- First --
-----------
when Attribute_First =>
Check_Array_Or_Scalar_Type;
---------------
-- First_Bit --
---------------
when Attribute_First_Bit =>
Check_Component;
Set_Etype (N, Universal_Integer);
-----------------
-- Fixed_Value --
-----------------
when Attribute_Fixed_Value =>
Check_E1;
Check_Fixed_Point_Type;
Resolve (E1, Any_Integer);
Set_Etype (N, P_Base_Type);
-----------
-- Floor --
-----------
when Attribute_Floor =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
----------
-- Fore --
----------
when Attribute_Fore =>
Check_Fixed_Point_Type_0;
Set_Etype (N, Universal_Integer);
--------------
-- Fraction --
--------------
when Attribute_Fraction =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
-----------------------
-- Has_Discriminants --
-----------------------
when Attribute_Has_Discriminants =>
Legal_Formal_Attribute;
--------------
-- Identity --
--------------
when Attribute_Identity =>
Check_E0;
Analyze (P);
if Etype (P) = Standard_Exception_Type then
Set_Etype (N, RTE (RE_Exception_Id));
elsif Is_Task_Type (Etype (P))
or else (Is_Access_Type (Etype (P))
and then Is_Task_Type (Designated_Type (Etype (P))))
then
Resolve (P, Etype (P));
Set_Etype (N, RTE (RO_AT_Task_ID));
else
Error_Attr ("prefix of % attribute must be a task or an "
& "exception", P);
end if;
-----------
-- Image --
-----------
when Attribute_Image => Image :
begin
Set_Etype (N, Standard_String);
Check_Scalar_Type;
if Is_Real_Type (P_Type) then
if Ada_83 and then Comes_From_Source (N) then
Error_Msg_Name_1 := Aname;
Error_Msg_N
("(Ada 83) % attribute not allowed for real types", N);
end if;
end if;
if Is_Enumeration_Type (P_Type) then
Check_Restriction (No_Enumeration_Maps, N);
end if;
Check_E1;
Resolve (E1, P_Base_Type);
Check_Enum_Image;
Validate_Non_Static_Attribute_Function_Call;
end Image;
---------
-- Img --
---------
when Attribute_Img => Img :
begin
Set_Etype (N, Standard_String);
if not Is_Scalar_Type (P_Type)
or else (Is_Entity_Name (P) and then Is_Type (Entity (P)))
then
Error_Attr
("prefix of % attribute must be scalar object name", N);
end if;
Check_Enum_Image;
end Img;
-----------
-- Input --
-----------
when Attribute_Input =>
Check_E1;
Check_Stream_Attribute (Name_uInput);
Disallow_In_No_Run_Time_Mode (N);
Set_Etype (N, P_Base_Type);
-------------------
-- Integer_Value --
-------------------
when Attribute_Integer_Value =>
Check_E1;
Check_Integer_Type;
Resolve (E1, Any_Fixed);
Set_Etype (N, P_Base_Type);
-----------
-- Large --
-----------
when Attribute_Large =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
----------
-- Last --
----------
when Attribute_Last =>
Check_Array_Or_Scalar_Type;
--------------
-- Last_Bit --
--------------
when Attribute_Last_Bit =>
Check_Component;
Set_Etype (N, Universal_Integer);
------------------
-- Leading_Part --
------------------
when Attribute_Leading_Part =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
Resolve (E2, Any_Integer);
------------
-- Length --
------------
when Attribute_Length =>
Check_Array_Type;
Set_Etype (N, Universal_Integer);
-------------
-- Machine --
-------------
when Attribute_Machine =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
------------------
-- Machine_Emax --
------------------
when Attribute_Machine_Emax =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
------------------
-- Machine_Emin --
------------------
when Attribute_Machine_Emin =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
----------------------
-- Machine_Mantissa --
----------------------
when Attribute_Machine_Mantissa =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
-----------------------
-- Machine_Overflows --
-----------------------
when Attribute_Machine_Overflows =>
Check_Real_Type;
Check_E0;
Set_Etype (N, Standard_Boolean);
-------------------
-- Machine_Radix --
-------------------
when Attribute_Machine_Radix =>
Check_Real_Type;
Check_E0;
Set_Etype (N, Universal_Integer);
--------------------
-- Machine_Rounds --
--------------------
when Attribute_Machine_Rounds =>
Check_Real_Type;
Check_E0;
Set_Etype (N, Standard_Boolean);
------------------
-- Machine_Size --
------------------
when Attribute_Machine_Size =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
--------------
-- Mantissa --
--------------
when Attribute_Mantissa =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Integer);
---------
-- Max --
---------
when Attribute_Max =>
Check_E2;
Check_Scalar_Type;
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
Set_Etype (N, P_Base_Type);
----------------------------
-- Max_Interrupt_Priority --
----------------------------
when Attribute_Max_Interrupt_Priority =>
Standard_Attribute
(UI_To_Int
(Expr_Value
(Expression
(Parent (RTE (RE_Max_Interrupt_Priority))))));
------------------
-- Max_Priority --
------------------
when Attribute_Max_Priority =>
Standard_Attribute
(UI_To_Int
(Expr_Value
(Expression
(Parent (RTE (RE_Max_Priority))))));
----------------------------------
-- Max_Size_In_Storage_Elements --
----------------------------------
when Attribute_Max_Size_In_Storage_Elements =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
-----------------------
-- Maximum_Alignment --
-----------------------
when Attribute_Maximum_Alignment =>
Standard_Attribute (Ttypes.Maximum_Alignment);
--------------------
-- Mechanism_Code --
--------------------
when Attribute_Mechanism_Code =>
if not Is_Entity_Name (P)
or else not Is_Subprogram (Entity (P))
then
Error_Attr ("prefix of % attribute must be subprogram", P);
end if;
Check_Either_E0_Or_E1;
if Present (E1) then
Resolve (E1, Any_Integer);
Set_Etype (E1, Standard_Integer);
if not Is_Static_Expression (E1) then
Error_Attr
("expression for parameter number must be static", E1);
elsif UI_To_Int (Intval (E1)) > Number_Formals (Entity (P))
or else UI_To_Int (Intval (E1)) < 0
then
Error_Attr ("invalid parameter number for %attribute", E1);
end if;
end if;
Set_Etype (N, Universal_Integer);
---------
-- Min --
---------
when Attribute_Min =>
Check_E2;
Check_Scalar_Type;
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
Set_Etype (N, P_Base_Type);
-----------
-- Model --
-----------
when Attribute_Model =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
----------------
-- Model_Emin --
----------------
when Attribute_Model_Emin =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
-------------------
-- Model_Epsilon --
-------------------
when Attribute_Model_Epsilon =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Real);
--------------------
-- Model_Mantissa --
--------------------
when Attribute_Model_Mantissa =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
-----------------
-- Model_Small --
-----------------
when Attribute_Model_Small =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Real);
-------------
-- Modulus --
-------------
when Attribute_Modulus =>
Check_E0;
Check_Type;
if not Is_Modular_Integer_Type (P_Type) then
Error_Attr ("prefix of % attribute must be modular type", P);
end if;
Set_Etype (N, Universal_Integer);
--------------------
-- Null_Parameter --
--------------------
when Attribute_Null_Parameter => Null_Parameter : declare
Parnt : constant Node_Id := Parent (N);
GParnt : constant Node_Id := Parent (Parnt);
procedure Bad_Null_Parameter (Msg : String);
-- Used if bad Null parameter attribute node is found. Issues
-- given error message, and also sets the type to Any_Type to
-- avoid blowups later on from dealing with a junk node.
procedure Must_Be_Imported (Proc_Ent : Entity_Id);
-- Called to check that Proc_Ent is imported subprogram
------------------------
-- Bad_Null_Parameter --
------------------------
procedure Bad_Null_Parameter (Msg : String) is
begin
Error_Msg_N (Msg, N);
Set_Etype (N, Any_Type);
end Bad_Null_Parameter;
----------------------
-- Must_Be_Imported --
----------------------
procedure Must_Be_Imported (Proc_Ent : Entity_Id) is
Pent : Entity_Id := Proc_Ent;
begin
while Present (Alias (Pent)) loop
Pent := Alias (Pent);
end loop;
-- Ignore check if procedure not frozen yet (we will get
-- another chance when the default parameter is reanalyzed)
if not Is_Frozen (Pent) then
return;
elsif not Is_Imported (Pent) then
Bad_Null_Parameter
("Null_Parameter can only be used with imported subprogram");
else
return;
end if;
end Must_Be_Imported;
-- Start of processing for Null_Parameter
begin
Check_Type;
Check_E0;
Set_Etype (N, P_Type);
-- Case of attribute used as default expression
if Nkind (Parnt) = N_Parameter_Specification then
Must_Be_Imported (Defining_Entity (GParnt));
-- Case of attribute used as actual for subprogram (positional)
elsif (Nkind (Parnt) = N_Procedure_Call_Statement
or else
Nkind (Parnt) = N_Function_Call)
and then Is_Entity_Name (Name (Parnt))
then
Must_Be_Imported (Entity (Name (Parnt)));
-- Case of attribute used as actual for subprogram (named)
elsif Nkind (Parnt) = N_Parameter_Association
and then (Nkind (GParnt) = N_Procedure_Call_Statement
or else
Nkind (GParnt) = N_Function_Call)
and then Is_Entity_Name (Name (GParnt))
then
Must_Be_Imported (Entity (Name (GParnt)));
-- Not an allowed case
else
Bad_Null_Parameter
("Null_Parameter must be actual or default parameter");
end if;
end Null_Parameter;
-----------------
-- Object_Size --
-----------------
when Attribute_Object_Size =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
------------
-- Output --
------------
when Attribute_Output =>
Check_E2;
Check_Stream_Attribute (Name_uInput);
Set_Etype (N, Standard_Void_Type);
Disallow_In_No_Run_Time_Mode (N);
Resolve (N, Standard_Void_Type);
------------------
-- Partition_ID --
------------------
when Attribute_Partition_ID =>
Check_E0;
if P_Type /= Any_Type then
if not Is_Library_Level_Entity (Entity (P)) then
Error_Attr
("prefix of % attribute must be library-level entity", P);
-- The defining entity of prefix should not be declared inside
-- a Pure unit. RM E.1(8).
-- The Is_Pure flag has been set during declaration.
elsif Is_Entity_Name (P)
and then Is_Pure (Entity (P))
then
Error_Attr
("prefix of % attribute must not be declared pure", P);
end if;
end if;
Set_Etype (N, Universal_Integer);
-------------------------
-- Passed_By_Reference --
-------------------------
when Attribute_Passed_By_Reference =>
Check_E0;
Check_Type;
Set_Etype (N, Standard_Boolean);
---------
-- Pos --
---------
when Attribute_Pos =>
Check_Discrete_Type;
Check_E1;
Resolve (E1, P_Base_Type);
Set_Etype (N, Universal_Integer);
--------------
-- Position --
--------------
when Attribute_Position =>
Check_Component;
Set_Etype (N, Universal_Integer);
----------
-- Pred --
----------
when Attribute_Pred =>
Check_Scalar_Type;
Check_E1;
Resolve (E1, P_Base_Type);
Set_Etype (N, P_Base_Type);
-- Nothing to do for real type case
if Is_Real_Type (P_Type) then
null;
-- If not modular type, test for overflow check required
else
if not Is_Modular_Integer_Type (P_Type)
and then not Range_Checks_Suppressed (P_Base_Type)
then
Enable_Range_Check (E1);
end if;
end if;
-----------
-- Range --
-----------
when Attribute_Range =>
Check_Array_Or_Scalar_Type;
if Ada_83
and then Is_Scalar_Type (P_Type)
and then Comes_From_Source (N)
then
Error_Attr
("(Ada 83) % attribute not allowed for scalar type", P);
end if;
------------------
-- Range_Length --
------------------
when Attribute_Range_Length =>
Check_Discrete_Type;
Set_Etype (N, Universal_Integer);
----------
-- Read --
----------
when Attribute_Read =>
Check_E2;
Check_Stream_Attribute (Name_uRead);
Set_Etype (N, Standard_Void_Type);
Resolve (N, Standard_Void_Type);
Disallow_In_No_Run_Time_Mode (N);
Note_Possible_Modification (E2);
---------------
-- Remainder --
---------------
when Attribute_Remainder =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
-----------
-- Round --
-----------
when Attribute_Round =>
Check_E1;
Check_Decimal_Fixed_Point_Type;
Set_Etype (N, P_Base_Type);
-- Because the context is universal_real (3.5.10(12)) it is a legal
-- context for a universal fixed expression. This is the only
-- attribute whose functional description involves U_R.
if Etype (E1) = Universal_Fixed then
declare
Conv : constant Node_Id := Make_Type_Conversion (Loc,
Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc),
Expression => Relocate_Node (E1));
begin
Rewrite (E1, Conv);
Analyze (E1);
end;
end if;
Resolve (E1, Any_Real);
--------------
-- Rounding --
--------------
when Attribute_Rounding =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
---------------
-- Safe_Emax --
---------------
when Attribute_Safe_Emax =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
----------------
-- Safe_First --
----------------
when Attribute_Safe_First =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Real);
----------------
-- Safe_Large --
----------------
when Attribute_Safe_Large =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
---------------
-- Safe_Last --
---------------
when Attribute_Safe_Last =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Real);
----------------
-- Safe_Small --
----------------
when Attribute_Safe_Small =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
-----------
-- Scale --
-----------
when Attribute_Scale =>
Check_E0;
Check_Decimal_Fixed_Point_Type;
Set_Etype (N, Universal_Integer);
-------------
-- Scaling --
-------------
when Attribute_Scaling =>
Check_Floating_Point_Type_2;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
------------------
-- Signed_Zeros --
------------------
when Attribute_Signed_Zeros =>
Check_Floating_Point_Type_0;
Set_Etype (N, Standard_Boolean);
----------
-- Size --
----------
when Attribute_Size | Attribute_VADS_Size =>
Check_E0;
if Is_Object_Reference (P)
or else (Is_Entity_Name (P)
and then Ekind (Entity (P)) = E_Function)
then
Check_Object_Reference (P);
elsif Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
null;
elsif Nkind (P) = N_Type_Conversion
and then not Comes_From_Source (P)
then
null;
else
Error_Attr ("invalid prefix for % attribute", P);
end if;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
-----------
-- Small --
-----------
when Attribute_Small =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
------------------
-- Storage_Pool --
------------------
when Attribute_Storage_Pool =>
if Is_Access_Type (P_Type) then
Check_E0;
-- Set appropriate entity
if Present (Associated_Storage_Pool (Root_Type (P_Type))) then
Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type)));
else
Set_Entity (N, RTE (RE_Global_Pool_Object));
end if;
Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
-- Validate_Remote_Access_To_Class_Wide_Type for attribute
-- Storage_Pool since this attribute is not defined for such
-- types (RM E.2.3(22)).
Validate_Remote_Access_To_Class_Wide_Type (N);
else
Error_Attr ("prefix of % attribute must be access type", P);
end if;
------------------
-- Storage_Size --
------------------
when Attribute_Storage_Size =>
if Is_Task_Type (P_Type) then
Check_E0;
Set_Etype (N, Universal_Integer);
elsif Is_Access_Type (P_Type) then
if Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
Check_E0;
Check_Type;
Set_Etype (N, Universal_Integer);
-- Validate_Remote_Access_To_Class_Wide_Type for attribute
-- Storage_Size since this attribute is not defined for
-- such types (RM E.2.3(22)).
Validate_Remote_Access_To_Class_Wide_Type (N);
-- The prefix is allowed to be an implicit dereference
-- of an access value designating a task.
else
Check_E0;
Check_Task_Prefix;
Set_Etype (N, Universal_Integer);
end if;
else
Error_Attr
("prefix of % attribute must be access or task type", P);
end if;
------------------
-- Storage_Unit --
------------------
when Attribute_Storage_Unit =>
Standard_Attribute (Ttypes.System_Storage_Unit);
----------
-- Succ --
----------
when Attribute_Succ =>
Check_Scalar_Type;
Check_E1;
Resolve (E1, P_Base_Type);
Set_Etype (N, P_Base_Type);
-- Nothing to do for real type case
if Is_Real_Type (P_Type) then
null;
-- If not modular type, test for overflow check required.
else
if not Is_Modular_Integer_Type (P_Type)
and then not Range_Checks_Suppressed (P_Base_Type)
then
Enable_Range_Check (E1);
end if;
end if;
---------
-- Tag --
---------
when Attribute_Tag =>
Check_E0;
Check_Dereference;
if not Is_Tagged_Type (P_Type) then
Error_Attr ("prefix of % attribute must be tagged", P);
-- Next test does not apply to generated code
-- why not, and what does the illegal reference mean???
elsif Is_Object_Reference (P)
and then not Is_Class_Wide_Type (P_Type)
and then Comes_From_Source (N)
then
Error_Attr
("% attribute can only be applied to objects of class-wide type",
P);
end if;
Set_Etype (N, RTE (RE_Tag));
----------------
-- Terminated --
----------------
when Attribute_Terminated =>
Check_E0;
Set_Etype (N, Standard_Boolean);
Check_Task_Prefix;
----------
-- Tick --
----------
when Attribute_Tick =>
Check_Standard_Prefix;
Rewrite (N,
Make_Real_Literal (Loc,
UR_From_Components (
Num => UI_From_Int (Ttypes.System_Tick_Nanoseconds),
Den => UI_From_Int (9),
Rbase => 10)));
Analyze (N);
----------------
-- To_Address --
----------------
when Attribute_To_Address =>
Check_E1;
Analyze (P);
if Nkind (P) /= N_Identifier
or else Chars (P) /= Name_System
then
Error_Attr ("prefix of %attribute must be System", P);
end if;
Generate_Reference (RTE (RE_Address), P);
Analyze_And_Resolve (E1, Any_Integer);
Set_Etype (N, RTE (RE_Address));
----------------
-- Truncation --
----------------
when Attribute_Truncation =>
Check_Floating_Point_Type_1;
Resolve (E1, P_Base_Type);
Set_Etype (N, P_Base_Type);
----------------
-- Type_Class --
----------------
when Attribute_Type_Class =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, RTE (RE_Type_Class));
-----------------
-- UET_Address --
-----------------
when Attribute_UET_Address =>
Check_E0;
Check_Unit_Name (P);
Set_Etype (N, RTE (RE_Address));
-----------------------
-- Unbiased_Rounding --
-----------------------
when Attribute_Unbiased_Rounding =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
----------------------
-- Unchecked_Access --
----------------------
when Attribute_Unchecked_Access =>
if Comes_From_Source (N) then
Check_Restriction (No_Unchecked_Access, N);
end if;
Access_Attribute;
------------------------------
-- Universal_Literal_String --
------------------------------
-- This is a GNAT specific attribute whose prefix must be a named
-- number where the expression is either a single numeric literal,
-- or a numeric literal immediately preceded by a minus sign. The
-- result is equivalent to a string literal containing the text of
-- the literal as it appeared in the source program with a possible
-- leading minus sign.
when Attribute_Universal_Literal_String => Universal_Literal_String :
begin
Check_E0;
if not Is_Entity_Name (P)
or else Ekind (Entity (P)) not in Named_Kind
then
Error_Attr ("prefix for % attribute must be named number", P);
else
declare
Expr : Node_Id;
Negative : Boolean;
S : Source_Ptr;
Src : Source_Buffer_Ptr;
begin
Expr := Original_Node (Expression (Parent (Entity (P))));
if Nkind (Expr) = N_Op_Minus then
Negative := True;
Expr := Original_Node (Right_Opnd (Expr));
else
Negative := False;
end if;
if Nkind (Expr) /= N_Integer_Literal
and then Nkind (Expr) /= N_Real_Literal
then
Error_Attr
("named number for % attribute must be simple literal", N);
end if;
-- Build string literal corresponding to source literal text
Start_String;
if Negative then
Store_String_Char (Get_Char_Code ('-'));
end if;
S := Sloc (Expr);
Src := Source_Text (Get_Source_File_Index (S));
while Src (S) /= ';' and then Src (S) /= ' ' loop
Store_String_Char (Get_Char_Code (Src (S)));
S := S + 1;
end loop;
-- Now we rewrite the attribute with the string literal
Rewrite (N,
Make_String_Literal (Loc, End_String));
Analyze (N);
end;
end if;
end Universal_Literal_String;
-------------------------
-- Unrestricted_Access --
-------------------------
-- This is a GNAT specific attribute which is like Access except that
-- all scope checks and checks for aliased views are omitted.
when Attribute_Unrestricted_Access =>
if Comes_From_Source (N) then
Check_Restriction (No_Unchecked_Access, N);
end if;
if Is_Entity_Name (P) then
Set_Address_Taken (Entity (P));
end if;
Access_Attribute;
---------
-- Val --
---------
when Attribute_Val => Val : declare
begin
Check_E1;
Check_Discrete_Type;
Resolve (E1, Any_Integer);
Set_Etype (N, P_Base_Type);
-- Note, we need a range check in general, but we wait for the
-- Resolve call to do this, since we want to let Eval_Attribute
-- have a chance to find an static illegality first!
end Val;
-----------
-- Valid --
-----------
when Attribute_Valid =>
Check_E0;
-- Ignore check for object if we have a 'Valid reference generated
-- by the expanded code, since in some cases valid checks can occur
-- on items that are names, but are not objects (e.g. attributes).
if Comes_From_Source (N) then
Check_Object_Reference (P);
end if;
if not Is_Scalar_Type (P_Type) then
Error_Attr ("object for % attribute must be of scalar type", P);
end if;
Set_Etype (N, Standard_Boolean);
-----------
-- Value --
-----------
when Attribute_Value => Value :
begin
Check_E1;
Check_Scalar_Type;
if Is_Enumeration_Type (P_Type) then
Check_Restriction (No_Enumeration_Maps, N);
end if;
-- Set Etype before resolving expression because expansion
-- of expression may require enclosing type.
Set_Etype (N, P_Type);
Validate_Non_Static_Attribute_Function_Call;
end Value;
----------------
-- Value_Size --
----------------
when Attribute_Value_Size =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
-------------
-- Version --
-------------
when Attribute_Version =>
Check_E0;
Check_Program_Unit;
Set_Etype (N, RTE (RE_Version_String));
------------------
-- Wchar_T_Size --
------------------
when Attribute_Wchar_T_Size =>
Standard_Attribute (Interfaces_Wchar_T_Size);
----------------
-- Wide_Image --
----------------
when Attribute_Wide_Image => Wide_Image :
begin
Check_Scalar_Type;
Set_Etype (N, Standard_Wide_String);
Check_E1;
Resolve (E1, P_Base_Type);
Validate_Non_Static_Attribute_Function_Call;
end Wide_Image;
----------------
-- Wide_Value --
----------------
when Attribute_Wide_Value => Wide_Value :
begin
Check_E1;
Check_Scalar_Type;
-- Set Etype before resolving expression because expansion
-- of expression may require enclosing type.
Set_Etype (N, P_Type);
Validate_Non_Static_Attribute_Function_Call;
end Wide_Value;
----------------
-- Wide_Width --
----------------
when Attribute_Wide_Width =>
Check_E0;
Check_Scalar_Type;
Set_Etype (N, Universal_Integer);
-----------
-- Width --
-----------
when Attribute_Width =>
Check_E0;
Check_Scalar_Type;
Set_Etype (N, Universal_Integer);
---------------
-- Word_Size --
---------------
when Attribute_Word_Size =>
Standard_Attribute (System_Word_Size);
-----------
-- Write --
-----------
when Attribute_Write =>
Check_E2;
Check_Stream_Attribute (Name_uWrite);
Set_Etype (N, Standard_Void_Type);
Disallow_In_No_Run_Time_Mode (N);
Resolve (N, Standard_Void_Type);
end case;
-- All errors raise Bad_Attribute, so that we get out before any further
-- damage occurs when an error is detected (for example, if we check for
-- one attribute expression, and the check succeeds, we want to be able
-- to proceed securely assuming that an expression is in fact present.
exception
when Bad_Attribute =>
Set_Etype (N, Any_Type);
return;
end Analyze_Attribute;
--------------------
-- Eval_Attribute --
--------------------
procedure Eval_Attribute (N : Node_Id) is
Loc : constant Source_Ptr := Sloc (N);
Aname : constant Name_Id := Attribute_Name (N);
Id : constant Attribute_Id := Get_Attribute_Id (Aname);
P : constant Node_Id := Prefix (N);
C_Type : constant Entity_Id := Etype (N);
-- The type imposed by the context.
E1 : Node_Id;
-- First expression, or Empty if none
E2 : Node_Id;
-- Second expression, or Empty if none
P_Entity : Entity_Id;
-- Entity denoted by prefix
P_Type : Entity_Id;
-- The type of the prefix
P_Base_Type : Entity_Id;
-- The base type of the prefix type
P_Root_Type : Entity_Id;
-- The root type of the prefix type
Static : Boolean;
-- True if prefix type is static
Lo_Bound, Hi_Bound : Node_Id;
-- Expressions for low and high bounds of type or array index referenced
-- by First, Last, or Length attribute for array, set by Set_Bounds.
CE_Node : Node_Id;
-- Constraint error node used if we have an attribute reference has
-- an argument that raises a constraint error. In this case we replace
-- the attribute with a raise constraint_error node. This is important
-- processing, since otherwise gigi might see an attribute which it is
-- unprepared to deal with.
function Aft_Value return Nat;
-- Computes Aft value for current attribute prefix (used by Aft itself
-- and also by Width for computing the Width of a fixed point type).
procedure Check_Expressions;
-- In case where the attribute is not foldable, the expressions, if
-- any, of the attribute, are in a non-static context. This procedure
-- performs the required additional checks.
procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint);
-- This procedure is called when the attribute N has a non-static
-- but compile time known value given by Val. It includes the
-- necessary checks for out of range values.
procedure Float_Attribute_Universal_Integer
(IEEES_Val : Int;
IEEEL_Val : Int;
IEEEX_Val : Int;
VAXFF_Val : Int;
VAXDF_Val : Int;
VAXGF_Val : Int);
-- This procedure evaluates a float attribute with no arguments that
-- returns a universal integer result. The parameters give the values
-- for the possible floating-point root types. See ttypef for details.
-- The prefix type is a float type (and is thus not a generic type).
procedure Float_Attribute_Universal_Real
(IEEES_Val : String;
IEEEL_Val : String;
IEEEX_Val : String;
VAXFF_Val : String;
VAXDF_Val : String;
VAXGF_Val : String);
-- This procedure evaluates a float attribute with no arguments that
-- returns a universal real result. The parameters give the values
-- required for the possible floating-point root types in string
-- format as real literals with a possible leading minus sign.
-- The prefix type is a float type (and is thus not a generic type).
function Fore_Value return Nat;
-- Computes the Fore value for the current attribute prefix, which is
-- known to be a static fixed-point type. Used by Fore and Width.
function Mantissa return Uint;
-- Returns the Mantissa value for the prefix type
procedure Set_Bounds;
-- Used for First, Last and Length attributes applied to an array or
-- array subtype. Sets the variables Index_Lo and Index_Hi to the low
-- and high bound expressions for the index referenced by the attribute
-- designator (i.e. the first index if no expression is present, and
-- the N'th index if the value N is present as an expression). Also
-- used for First and Last of scalar types.
---------------
-- Aft_Value --
---------------
function Aft_Value return Nat is
Result : Nat;
Delta_Val : Ureal;
begin
Result := 1;
Delta_Val := Delta_Value (P_Type);
while Delta_Val < Ureal_Tenth loop
Delta_Val := Delta_Val * Ureal_10;
Result := Result + 1;
end loop;
return Result;
end Aft_Value;
-----------------------
-- Check_Expressions --
-----------------------
procedure Check_Expressions is
E : Node_Id := E1;
begin
while Present (E) loop
Check_Non_Static_Context (E);
Next (E);
end loop;
end Check_Expressions;
----------------------------------
-- Compile_Time_Known_Attribute --
----------------------------------
procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is
T : constant Entity_Id := Etype (N);
begin
Fold_Uint (N, Val);
Set_Is_Static_Expression (N, False);
-- Check that result is in bounds of the type if it is static
if Is_In_Range (N, T) then
null;
elsif Is_Out_Of_Range (N, T) then
Apply_Compile_Time_Constraint_Error
(N, "value not in range of}?");
elsif not Range_Checks_Suppressed (T) then
Enable_Range_Check (N);
else
Set_Do_Range_Check (N, False);
end if;
end Compile_Time_Known_Attribute;
---------------------------------------
-- Float_Attribute_Universal_Integer --
---------------------------------------
procedure Float_Attribute_Universal_Integer
(IEEES_Val : Int;
IEEEL_Val : Int;
IEEEX_Val : Int;
VAXFF_Val : Int;
VAXDF_Val : Int;
VAXGF_Val : Int)
is
Val : Int;
Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
begin
if not Vax_Float (P_Base_Type) then
if Digs = IEEES_Digits then
Val := IEEES_Val;
elsif Digs = IEEEL_Digits then
Val := IEEEL_Val;
else pragma Assert (Digs = IEEEX_Digits);
Val := IEEEX_Val;
end if;
else
if Digs = VAXFF_Digits then
Val := VAXFF_Val;
elsif Digs = VAXDF_Digits then
Val := VAXDF_Val;
else pragma Assert (Digs = VAXGF_Digits);
Val := VAXGF_Val;
end if;
end if;
Fold_Uint (N, UI_From_Int (Val));
end Float_Attribute_Universal_Integer;
------------------------------------
-- Float_Attribute_Universal_Real --
------------------------------------
procedure Float_Attribute_Universal_Real
(IEEES_Val : String;
IEEEL_Val : String;
IEEEX_Val : String;
VAXFF_Val : String;
VAXDF_Val : String;
VAXGF_Val : String)
is
Val : Node_Id;
Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type));
begin
if not Vax_Float (P_Base_Type) then
if Digs = IEEES_Digits then
Val := Real_Convert (IEEES_Val);
elsif Digs = IEEEL_Digits then
Val := Real_Convert (IEEEL_Val);
else pragma Assert (Digs = IEEEX_Digits);
Val := Real_Convert (IEEEX_Val);
end if;
else
if Digs = VAXFF_Digits then
Val := Real_Convert (VAXFF_Val);
elsif Digs = VAXDF_Digits then
Val := Real_Convert (VAXDF_Val);
else pragma Assert (Digs = VAXGF_Digits);
Val := Real_Convert (VAXGF_Val);
end if;
end if;
Set_Sloc (Val, Loc);
Rewrite (N, Val);
Analyze_And_Resolve (N, C_Type);
end Float_Attribute_Universal_Real;
----------------
-- Fore_Value --
----------------
-- Note that the Fore calculation is based on the actual values
-- of the bounds, and does not take into account possible rounding.
function Fore_Value return Nat is
Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type));
Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type));
Small : constant Ureal := Small_Value (P_Type);
Lo_Real : constant Ureal := Lo * Small;
Hi_Real : constant Ureal := Hi * Small;
T : Ureal;
R : Nat;
begin
-- Bounds are given in terms of small units, so first compute
-- proper values as reals.
T := UR_Max (abs Lo_Real, abs Hi_Real);
R := 2;
-- Loop to compute proper value if more than one digit required
while T >= Ureal_10 loop
R := R + 1;
T := T / Ureal_10;
end loop;
return R;
end Fore_Value;
--------------
-- Mantissa --
--------------
-- Table of mantissa values accessed by function Computed using
-- the relation:
-- T'Mantissa = integer next above (D * log(10)/log(2)) + 1)
-- where D is T'Digits (RM83 3.5.7)
Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := (
1 => 5,
2 => 8,
3 => 11,
4 => 15,
5 => 18,
6 => 21,
7 => 25,
8 => 28,
9 => 31,
10 => 35,
11 => 38,
12 => 41,
13 => 45,
14 => 48,
15 => 51,
16 => 55,
17 => 58,
18 => 61,
19 => 65,
20 => 68,
21 => 71,
22 => 75,
23 => 78,
24 => 81,
25 => 85,
26 => 88,
27 => 91,
28 => 95,
29 => 98,
30 => 101,
31 => 104,
32 => 108,
33 => 111,
34 => 114,
35 => 118,
36 => 121,
37 => 124,
38 => 128,
39 => 131,
40 => 134);
function Mantissa return Uint is
begin
return
UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type))));
end Mantissa;
----------------
-- Set_Bounds --
----------------
procedure Set_Bounds is
Ndim : Nat;
Indx : Node_Id;
Ityp : Entity_Id;
begin
-- For a string literal subtype, we have to construct the bounds.
-- Valid Ada code never applies attributes to string literals, but
-- it is convenient to allow the expander to generate attribute
-- references of this type (e.g. First and Last applied to a string
-- literal).
-- Note that the whole point of the E_String_Literal_Subtype is to
-- avoid this construction of bounds, but the cases in which we
-- have to materialize them are rare enough that we don't worry!
-- The low bound is simply the low bound of the base type. The
-- high bound is computed from the length of the string and this
-- low bound.
if Ekind (P_Type) = E_String_Literal_Subtype then
Lo_Bound :=
Type_Low_Bound (Etype (First_Index (Base_Type (P_Type))));
Hi_Bound :=
Make_Integer_Literal (Sloc (P),
Intval =>
Expr_Value (Lo_Bound) + String_Literal_Length (P_Type) - 1);
Set_Parent (Hi_Bound, P);
Analyze_And_Resolve (Hi_Bound, Etype (Lo_Bound));
return;
-- For non-array case, just get bounds of scalar type
elsif Is_Scalar_Type (P_Type) then
Ityp := P_Type;
if Is_Fixed_Point_Type (P_Type)
and then not Is_Frozen (Base_Type (P_Type))
and then Compile_Time_Known_Value (Type_Low_Bound (P_Type))
and then Compile_Time_Known_Value (Type_High_Bound (P_Type))
then
Freeze_Fixed_Point_Type (Base_Type (P_Type));
end if;
-- For array case, get type of proper index
else
if No (E1) then
Ndim := 1;
else
Ndim := UI_To_Int (Expr_Value (E1));
end if;
Indx := First_Index (P_Type);
for J in 1 .. Ndim - 1 loop
Next_Index (Indx);
end loop;
-- If no index type, get out (some other error occurred, and
-- we don't have enough information to complete the job!)
if No (Indx) then
Lo_Bound := Error;
Hi_Bound := Error;
return;
end if;
Ityp := Etype (Indx);
end if;
-- A discrete range in an index constraint is allowed to be a
-- subtype indication. This is syntactically a pain, but should
-- not propagate to the entity for the corresponding index subtype.
-- After checking that the subtype indication is legal, the range
-- of the subtype indication should be transfered to the entity.
-- The attributes for the bounds should remain the simple retrievals
-- that they are now.
Lo_Bound := Type_Low_Bound (Ityp);
Hi_Bound := Type_High_Bound (Ityp);
end Set_Bounds;
-- Start of processing for Eval_Attribute
begin
-- Acquire first two expressions (at the moment, no attributes
-- take more than two expressions in any case).
if Present (Expressions (N)) then
E1 := First (Expressions (N));
E2 := Next (E1);
else
E1 := Empty;
E2 := Empty;
end if;
-- Special processing for cases where the prefix is an object
if Is_Object_Reference (P) then
-- For Component_Size, the prefix is an array object, and we apply
-- the attribute to the type of the object. This is allowed for
-- both unconstrained and constrained arrays, since the bounds
-- have no influence on the value of this attribute.
if Id = Attribute_Component_Size then
P_Entity := Etype (P);
-- For First and Last, the prefix is an array object, and we apply
-- the attribute to the type of the array, but we need a constrained
-- type for this, so we use the actual subtype if available.
elsif Id = Attribute_First
or else
Id = Attribute_Last
or else
Id = Attribute_Length
then
declare
AS : constant Entity_Id := Get_Actual_Subtype_If_Available (P);
begin
if Present (AS) then
P_Entity := AS;
-- If no actual subtype, cannot fold
else
Check_Expressions;
return;
end if;
end;
-- For Size, give size of object if available, otherwise we
-- cannot fold Size.
elsif Id = Attribute_Size then
if Is_Entity_Name (P)
and then Known_Esize (Entity (P))
then
Compile_Time_Known_Attribute (N, Esize (Entity (P)));
return;
else
Check_Expressions;
return;
end if;
-- For Alignment, give size of object if available, otherwise we
-- cannot fold Alignment.
elsif Id = Attribute_Alignment then
if Is_Entity_Name (P)
and then Known_Alignment (Entity (P))
then
Fold_Uint (N, Alignment (Entity (P)));
Set_Is_Static_Expression (N, False);
return;
else
Check_Expressions;
return;
end if;
-- No other attributes for objects are folded
else
Check_Expressions;
return;
end if;
-- Cases where P is not an object. Cannot do anything if P is
-- not the name of an entity.
elsif not Is_Entity_Name (P) then
Check_Expressions;
return;
-- Otherwise get prefix entity
else
P_Entity := Entity (P);
end if;
-- At this stage P_Entity is the entity to which the attribute
-- is to be applied. This is usually simply the entity of the
-- prefix, except in some cases of attributes for objects, where
-- as described above, we apply the attribute to the object type.
-- First foldable possibility is a scalar or array type (RM 4.9(7))
-- that is not generic (generic types are eliminated by RM 4.9(25)).
-- Note we allow non-static non-generic types at this stage as further
-- described below.
if Is_Type (P_Entity)
and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
and then (not Is_Generic_Type (P_Entity))
then
P_Type := P_Entity;
-- Second foldable possibility is an array object (RM 4.9(8))
elsif (Ekind (P_Entity) = E_Variable
or else
Ekind (P_Entity) = E_Constant)
and then Is_Array_Type (Etype (P_Entity))
and then (not Is_Generic_Type (Etype (P_Entity)))
then
P_Type := Etype (P_Entity);
-- If the entity is an array constant with an unconstrained
-- nominal subtype then get the type from the initial value.
-- If the value has been expanded into assignments, the expression
-- is not present and the attribute reference remains dynamic.
-- We could do better here and retrieve the type ???
if Ekind (P_Entity) = E_Constant
and then not Is_Constrained (P_Type)
then
if No (Constant_Value (P_Entity)) then
return;
else
P_Type := Etype (Constant_Value (P_Entity));
end if;
end if;
-- Definite must be folded if the prefix is not a generic type,
-- that is to say if we are within an instantiation. Same processing
-- applies to the GNAT attributes Has_Discriminants and Type_Class
elsif (Id = Attribute_Definite
or else
Id = Attribute_Has_Discriminants
or else
Id = Attribute_Type_Class)
and then not Is_Generic_Type (P_Entity)
then
P_Type := P_Entity;
-- We can fold 'Size applied to a type if the size is known
-- (as happens for a size from an attribute definition clause).
-- At this stage, this can happen only for types (e.g. record
-- types) for which the size is always non-static. We exclude
-- generic types from consideration (since they have bogus
-- sizes set within templates).
elsif Id = Attribute_Size
and then Is_Type (P_Entity)
and then (not Is_Generic_Type (P_Entity))
and then Known_Static_RM_Size (P_Entity)
then
Compile_Time_Known_Attribute (N, RM_Size (P_Entity));
return;
-- No other cases are foldable (they certainly aren't static, and at
-- the moment we don't try to fold any cases other than the two above)
else
Check_Expressions;
return;
end if;
-- If either attribute or the prefix is Any_Type, then propagate
-- Any_Type to the result and don't do anything else at all.
if P_Type = Any_Type
or else (Present (E1) and then Etype (E1) = Any_Type)
or else (Present (E2) and then Etype (E2) = Any_Type)
then
Set_Etype (N, Any_Type);
return;
end if;
-- Scalar subtype case. We have not yet enforced the static requirement
-- of (RM 4.9(7)) and we don't intend to just yet, since there are cases
-- of non-static attribute references (e.g. S'Digits for a non-static
-- floating-point type, which we can compute at compile time).
-- Note: this folding of non-static attributes is not simply a case of
-- optimization. For many of the attributes affected, Gigi cannot handle
-- the attribute and depends on the front end having folded them away.
-- Note: although we don't require staticness at this stage, we do set
-- the Static variable to record the staticness, for easy reference by
-- those attributes where it matters (e.g. Succ and Pred), and also to
-- be used to ensure that non-static folded things are not marked as
-- being static (a check that is done right at the end).
P_Root_Type := Root_Type (P_Type);
P_Base_Type := Base_Type (P_Type);
-- If the root type or base type is generic, then we cannot fold. This
-- test is needed because subtypes of generic types are not always
-- marked as being generic themselves (which seems odd???)
if Is_Generic_Type (P_Root_Type)
or else Is_Generic_Type (P_Base_Type)
then
return;
end if;
if Is_Scalar_Type (P_Type) then
Static := Is_OK_Static_Subtype (P_Type);
-- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
-- since we can't do anything with unconstrained arrays. In addition,
-- only the First, Last and Length attributes are possibly static.
-- In addition Component_Size is possibly foldable, even though it
-- can never be static.
-- Definite, Has_Discriminants and Type_Class are again exceptions,
-- because they apply as well to unconstrained types.
elsif Id = Attribute_Definite
or else
Id = Attribute_Has_Discriminants
or else
Id = Attribute_Type_Class
then
Static := False;
else
if not Is_Constrained (P_Type)
or else (Id /= Attribute_Component_Size and then
Id /= Attribute_First and then
Id /= Attribute_Last and then
Id /= Attribute_Length)
then
Check_Expressions;
return;
end if;
-- The rules in (RM 4.9(7,8)) require a static array, but as in the
-- scalar case, we hold off on enforcing staticness, since there are
-- cases which we can fold at compile time even though they are not
-- static (e.g. 'Length applied to a static index, even though other
-- non-static indexes make the array type non-static). This is only
-- ab optimization, but it falls out essentially free, so why not.
-- Again we compute the variable Static for easy reference later
-- (note that no array attributes are static in Ada 83).
Static := Ada_95;
declare
N : Node_Id;
begin
N := First_Index (P_Type);
while Present (N) loop
Static := Static and Is_Static_Subtype (Etype (N));
Next_Index (N);
end loop;
end;
end if;
-- Check any expressions that are present. Note that these expressions,
-- depending on the particular attribute type, are either part of the
-- attribute designator, or they are arguments in a case where the
-- attribute reference returns a function. In the latter case, the
-- rule in (RM 4.9(22)) applies and in particular requires the type
-- of the expressions to be scalar in order for the attribute to be
-- considered to be static.
declare
E : Node_Id;
begin
E := E1;
while Present (E) loop
-- If expression is not static, then the attribute reference
-- certainly is neither foldable nor static, so we can quit
-- after calling Apply_Range_Check for 'Pos attributes.
-- We can also quit if the expression is not of a scalar type
-- as noted above.
if not Is_Static_Expression (E)
or else not Is_Scalar_Type (Etype (E))
then
if Id = Attribute_Pos then
if Is_Integer_Type (Etype (E)) then
Apply_Range_Check (E, Etype (N));
end if;
end if;
Check_Expressions;
return;
-- If the expression raises a constraint error, then so does
-- the attribute reference. We keep going in this case because
-- we are still interested in whether the attribute reference
-- is static even if it is not static.
elsif Raises_Constraint_Error (E) then
Set_Raises_Constraint_Error (N);
end if;
Next (E);
end loop;
if Raises_Constraint_Error (Prefix (N)) then
return;
end if;
end;
-- Deal with the case of a static attribute reference that raises
-- constraint error. The Raises_Constraint_Error flag will already
-- have been set, and the Static flag shows whether the attribute
-- reference is static. In any case we certainly can't fold such an
-- attribute reference.
-- Note that the rewriting of the attribute node with the constraint
-- error node is essential in this case, because otherwise Gigi might
-- blow up on one of the attributes it never expects to see.
-- The constraint_error node must have the type imposed by the context,
-- to avoid spurious errors in the enclosing expression.
if Raises_Constraint_Error (N) then
CE_Node :=
Make_Raise_Constraint_Error (Sloc (N));
Set_Etype (CE_Node, Etype (N));
Set_Raises_Constraint_Error (CE_Node);
Check_Expressions;
Rewrite (N, Relocate_Node (CE_Node));
Set_Is_Static_Expression (N, Static);
return;
end if;
-- At this point we have a potentially foldable attribute reference.
-- If Static is set, then the attribute reference definitely obeys
-- the requirements in (RM 4.9(7,8,22)), and it definitely can be
-- folded. If Static is not set, then the attribute may or may not
-- be foldable, and the individual attribute processing routines
-- test Static as required in cases where it makes a difference.
case Id is
--------------
-- Adjacent --
--------------
when Attribute_Adjacent =>
if Static then
Fold_Ureal (N,
Eval_Fat.Adjacent
(P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)));
end if;
---------
-- Aft --
---------
when Attribute_Aft =>
Fold_Uint (N, UI_From_Int (Aft_Value));
---------------
-- Alignment --
---------------
when Attribute_Alignment => Alignment_Block : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
-- Fold if alignment is set and not otherwise
if Known_Alignment (P_TypeA) then
Fold_Uint (N, Alignment (P_TypeA));
end if;
end Alignment_Block;
---------------
-- AST_Entry --
---------------
-- Can only be folded in No_Ast_Handler case
when Attribute_AST_Entry =>
if not Is_AST_Entry (P_Entity) then
Rewrite (N,
New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
else
null;
end if;
---------
-- Bit --
---------
-- Bit can never be folded
when Attribute_Bit =>
null;
------------------
-- Body_Version --
------------------
-- Body_version can never be static
when Attribute_Body_Version =>
null;
-------------
-- Ceiling --
-------------
when Attribute_Ceiling =>
if Static then
Fold_Ureal (N,
Eval_Fat.Ceiling (P_Root_Type, Expr_Value_R (E1)));
end if;
--------------------
-- Component_Size --
--------------------
when Attribute_Component_Size =>
if Component_Size (P_Type) /= 0 then
Fold_Uint (N, Component_Size (P_Type));
end if;
-------------
-- Compose --
-------------
when Attribute_Compose =>
if Static then
Fold_Ureal (N,
Eval_Fat.Compose
(P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)));
end if;
-----------------
-- Constrained --
-----------------
-- Constrained is never folded for now, there may be cases that
-- could be handled at compile time. to be looked at later.
when Attribute_Constrained =>
null;
---------------
-- Copy_Sign --
---------------
when Attribute_Copy_Sign =>
if Static then
Fold_Ureal (N,
Eval_Fat.Copy_Sign
(P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)));
end if;
-----------
-- Delta --
-----------
when Attribute_Delta =>
Fold_Ureal (N, Delta_Value (P_Type));
--------------
-- Definite --
--------------
when Attribute_Definite =>
declare
Result : Node_Id;
begin
if Is_Indefinite_Subtype (P_Entity) then
Result := New_Occurrence_Of (Standard_False, Loc);
else
Result := New_Occurrence_Of (Standard_True, Loc);
end if;
Rewrite (N, Result);
Analyze_And_Resolve (N, Standard_Boolean);
end;
------------
-- Denorm --
------------
when Attribute_Denorm =>
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Denorm_On_Target)));
------------
-- Digits --
------------
when Attribute_Digits =>
Fold_Uint (N, Digits_Value (P_Type));
----------
-- Emax --
----------
when Attribute_Emax =>
-- Ada 83 attribute is defined as (RM83 3.5.8)
-- T'Emax = 4 * T'Mantissa
Fold_Uint (N, 4 * Mantissa);
--------------
-- Enum_Rep --
--------------
when Attribute_Enum_Rep =>
if Static then
-- For an enumeration type with a non-standard representation
-- use the Enumeration_Rep field of the proper constant. Note
-- that this would not work for types Character/Wide_Character,
-- since no real entities are created for the enumeration
-- literals, but that does not matter since these two types
-- do not have non-standard representations anyway.
if Is_Enumeration_Type (P_Type)
and then Has_Non_Standard_Rep (P_Type)
then
Fold_Uint (N, Enumeration_Rep (Expr_Value_E (E1)));
-- For enumeration types with standard representations and all
-- other cases (i.e. all integer and modular types), Enum_Rep
-- is equivalent to Pos.
else
Fold_Uint (N, Expr_Value (E1));
end if;
end if;
-------------
-- Epsilon --
-------------
when Attribute_Epsilon =>
-- Ada 83 attribute is defined as (RM83 3.5.8)
-- T'Epsilon = 2.0**(1 - T'Mantissa)
Fold_Ureal (N, Ureal_2 ** (1 - Mantissa));
--------------
-- Exponent --
--------------
when Attribute_Exponent =>
if Static then
Fold_Uint (N,
Eval_Fat.Exponent (P_Root_Type, Expr_Value_R (E1)));
end if;
-----------
-- First --
-----------
when Attribute_First => First_Attr :
begin
Set_Bounds;
if Compile_Time_Known_Value (Lo_Bound) then
if Is_Real_Type (P_Type) then
Fold_Ureal (N, Expr_Value_R (Lo_Bound));
else
Fold_Uint (N, Expr_Value (Lo_Bound));
end if;
end if;
end First_Attr;
-----------------
-- Fixed_Value --
-----------------
when Attribute_Fixed_Value =>
null;
-----------
-- Floor --
-----------
when Attribute_Floor =>
if Static then
Fold_Ureal (N,
Eval_Fat.Floor (P_Root_Type, Expr_Value_R (E1)));
end if;
----------
-- Fore --
----------
when Attribute_Fore =>
if Static then
Fold_Uint (N, UI_From_Int (Fore_Value));
end if;
--------------
-- Fraction --
--------------
when Attribute_Fraction =>
if Static then
Fold_Ureal (N,
Eval_Fat.Fraction (P_Root_Type, Expr_Value_R (E1)));
end if;
-----------------------
-- Has_Discriminants --
-----------------------
when Attribute_Has_Discriminants =>
declare
Result : Node_Id;
begin
if Has_Discriminants (P_Entity) then
Result := New_Occurrence_Of (Standard_True, Loc);
else
Result := New_Occurrence_Of (Standard_False, Loc);
end if;
Rewrite (N, Result);
Analyze_And_Resolve (N, Standard_Boolean);
end;
--------------
-- Identity --
--------------
when Attribute_Identity =>
null;
-----------
-- Image --
-----------
-- Image is a scalar attribute, but is never static, because it is
-- not a static function (having a non-scalar argument (RM 4.9(22))
when Attribute_Image =>
null;
---------
-- Img --
---------
-- Img is a scalar attribute, but is never static, because it is
-- not a static function (having a non-scalar argument (RM 4.9(22))
when Attribute_Img =>
null;
-------------------
-- Integer_Value --
-------------------
when Attribute_Integer_Value =>
null;
-----------
-- Large --
-----------
when Attribute_Large =>
-- For fixed-point, we use the identity:
-- T'Large = (2.0**T'Mantissa - 1.0) * T'Small
if Is_Fixed_Point_Type (P_Type) then
Rewrite (N,
Make_Op_Multiply (Loc,
Left_Opnd =>
Make_Op_Subtract (Loc,
Left_Opnd =>
Make_Op_Expon (Loc,
Left_Opnd =>
Make_Real_Literal (Loc, Ureal_2),
Right_Opnd =>
Make_Attribute_Reference (Loc,
Prefix => P,
Attribute_Name => Name_Mantissa)),
Right_Opnd => Make_Real_Literal (Loc, Ureal_1)),
Right_Opnd =>
Make_Real_Literal (Loc, Small_Value (Entity (P)))));
Analyze_And_Resolve (N, C_Type);
-- Floating-point (Ada 83 compatibility)
else
-- Ada 83 attribute is defined as (RM83 3.5.8)
-- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa))
-- where
-- T'Emax = 4 * T'Mantissa
Fold_Ureal (N,
Ureal_2 ** (4 * Mantissa) *
(Ureal_1 - Ureal_2 ** (-Mantissa)));
end if;
----------
-- Last --
----------
when Attribute_Last => Last :
begin
Set_Bounds;
if Compile_Time_Known_Value (Hi_Bound) then
if Is_Real_Type (P_Type) then
Fold_Ureal (N, Expr_Value_R (Hi_Bound));
else
Fold_Uint (N, Expr_Value (Hi_Bound));
end if;
end if;
end Last;
------------------
-- Leading_Part --
------------------
when Attribute_Leading_Part =>
if Static then
Fold_Ureal (N,
Eval_Fat.Leading_Part
(P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)));
end if;
------------
-- Length --
------------
when Attribute_Length => Length :
begin
Set_Bounds;
if Compile_Time_Known_Value (Lo_Bound)
and then Compile_Time_Known_Value (Hi_Bound)
then
Fold_Uint (N,
UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))));
end if;
end Length;
-------------
-- Machine --
-------------
when Attribute_Machine =>
if Static then
Fold_Ureal (N,
Eval_Fat.Machine (P_Root_Type, Expr_Value_R (E1),
Eval_Fat.Round));
end if;
------------------
-- Machine_Emax --
------------------
when Attribute_Machine_Emax =>
Float_Attribute_Universal_Integer (
IEEES_Machine_Emax,
IEEEL_Machine_Emax,
IEEEX_Machine_Emax,
VAXFF_Machine_Emax,
VAXDF_Machine_Emax,
VAXGF_Machine_Emax);
------------------
-- Machine_Emin --
------------------
when Attribute_Machine_Emin =>
Float_Attribute_Universal_Integer (
IEEES_Machine_Emin,
IEEEL_Machine_Emin,
IEEEX_Machine_Emin,
VAXFF_Machine_Emin,
VAXDF_Machine_Emin,
VAXGF_Machine_Emin);
----------------------
-- Machine_Mantissa --
----------------------
when Attribute_Machine_Mantissa =>
Float_Attribute_Universal_Integer (
IEEES_Machine_Mantissa,
IEEEL_Machine_Mantissa,
IEEEX_Machine_Mantissa,
VAXFF_Machine_Mantissa,
VAXDF_Machine_Mantissa,
VAXGF_Machine_Mantissa);
-----------------------
-- Machine_Overflows --
-----------------------
when Attribute_Machine_Overflows =>
-- Always true for fixed-point
if Is_Fixed_Point_Type (P_Type) then
Fold_Uint (N, True_Value);
-- Floating point case
else
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)));
end if;
-------------------
-- Machine_Radix --
-------------------
when Attribute_Machine_Radix =>
if Is_Fixed_Point_Type (P_Type) then
if Is_Decimal_Fixed_Point_Type (P_Type)
and then Machine_Radix_10 (P_Type)
then
Fold_Uint (N, Uint_10);
else
Fold_Uint (N, Uint_2);
end if;
-- All floating-point type always have radix 2
else
Fold_Uint (N, Uint_2);
end if;
--------------------
-- Machine_Rounds --
--------------------
when Attribute_Machine_Rounds =>
-- Always False for fixed-point
if Is_Fixed_Point_Type (P_Type) then
Fold_Uint (N, False_Value);
-- Else yield proper floating-point result
else
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)));
end if;
------------------
-- Machine_Size --
------------------
-- Note: Machine_Size is identical to Object_Size
when Attribute_Machine_Size => Machine_Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if Known_Esize (P_TypeA) then
Fold_Uint (N, Esize (P_TypeA));
end if;
end Machine_Size;
--------------
-- Mantissa --
--------------
when Attribute_Mantissa =>
-- Fixed-point mantissa
if Is_Fixed_Point_Type (P_Type) then
-- Compile time foldable case
if Compile_Time_Known_Value (Type_Low_Bound (P_Type))
and then
Compile_Time_Known_Value (Type_High_Bound (P_Type))
then
-- The calculation of the obsolete Ada 83 attribute Mantissa
-- is annoying, because of AI00143, quoted here:
-- !question 84-01-10
-- Consider the model numbers for F:
-- type F is delta 1.0 range -7.0 .. 8.0;
-- The wording requires that F'MANTISSA be the SMALLEST
-- integer number for which each bound of the specified
-- range is either a model number or lies at most small
-- distant from a model number. This means F'MANTISSA
-- is required to be 3 since the range -7.0 .. 7.0 fits
-- in 3 signed bits, and 8 is "at most" 1.0 from a model
-- number, namely, 7. Is this analysis correct? Note that
-- this implies the upper bound of the range is not
-- represented as a model number.
-- !response 84-03-17
-- The analysis is correct. The upper and lower bounds for
-- a fixed point type can lie outside the range of model
-- numbers.
declare
Siz : Uint;
LBound : Ureal;
UBound : Ureal;
Bound : Ureal;
Max_Man : Uint;
begin
LBound := Expr_Value_R (Type_Low_Bound (P_Type));
UBound := Expr_Value_R (Type_High_Bound (P_Type));
Bound := UR_Max (UR_Abs (LBound), UR_Abs (UBound));
Max_Man := UR_Trunc (Bound / Small_Value (P_Type));
-- If the Bound is exactly a model number, i.e. a multiple
-- of Small, then we back it off by one to get the integer
-- value that must be representable.
if Small_Value (P_Type) * Max_Man = Bound then
Max_Man := Max_Man - 1;
end if;
-- Now find corresponding size = Mantissa value
Siz := Uint_0;
while 2 ** Siz < Max_Man loop
Siz := Siz + 1;
end loop;
Fold_Uint (N, Siz);
end;
else
-- The case of dynamic bounds cannot be evaluated at compile
-- time. Instead we use a runtime routine (see Exp_Attr).
null;
end if;
-- Floating-point Mantissa
else
Fold_Uint (N, Mantissa);
end if;
---------
-- Max --
---------
when Attribute_Max => Max :
begin
if Is_Real_Type (P_Type) then
Fold_Ureal (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)));
else
Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)));
end if;
end Max;
----------------------------------
-- Max_Size_In_Storage_Elements --
----------------------------------
-- Max_Size_In_Storage_Elements is simply the Size rounded up to a
-- Storage_Unit boundary. We can fold any cases for which the size
-- is known by the front end.
when Attribute_Max_Size_In_Storage_Elements =>
if Known_Esize (P_Type) then
Fold_Uint (N,
(Esize (P_Type) + System_Storage_Unit - 1) /
System_Storage_Unit);
end if;
--------------------
-- Mechanism_Code --
--------------------
when Attribute_Mechanism_Code =>
declare
Val : Int;
Formal : Entity_Id;
Mech : Mechanism_Type;
begin
if No (E1) then
Mech := Mechanism (P_Entity);
else
Val := UI_To_Int (Expr_Value (E1));
Formal := First_Formal (P_Entity);
for J in 1 .. Val - 1 loop
Next_Formal (Formal);
end loop;
Mech := Mechanism (Formal);
end if;
if Mech < 0 then
Fold_Uint (N, UI_From_Int (Int (-Mech)));
end if;
end;
---------
-- Min --
---------
when Attribute_Min => Min :
begin
if Is_Real_Type (P_Type) then
Fold_Ureal (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)));
else
Fold_Uint (N, UI_Min (Expr_Value (E1), Expr_Value (E2)));
end if;
end Min;
-----------
-- Model --
-----------
when Attribute_Model =>
if Static then
Fold_Ureal (N,
Eval_Fat.Model (P_Root_Type, Expr_Value_R (E1)));
end if;
----------------
-- Model_Emin --
----------------
when Attribute_Model_Emin =>
Float_Attribute_Universal_Integer (
IEEES_Model_Emin,
IEEEL_Model_Emin,
IEEEX_Model_Emin,
VAXFF_Model_Emin,
VAXDF_Model_Emin,
VAXGF_Model_Emin);
-------------------
-- Model_Epsilon --
-------------------
when Attribute_Model_Epsilon =>
Float_Attribute_Universal_Real (
IEEES_Model_Epsilon'Universal_Literal_String,
IEEEL_Model_Epsilon'Universal_Literal_String,
IEEEX_Model_Epsilon'Universal_Literal_String,
VAXFF_Model_Epsilon'Universal_Literal_String,
VAXDF_Model_Epsilon'Universal_Literal_String,
VAXGF_Model_Epsilon'Universal_Literal_String);
--------------------
-- Model_Mantissa --
--------------------
when Attribute_Model_Mantissa =>
Float_Attribute_Universal_Integer (
IEEES_Model_Mantissa,
IEEEL_Model_Mantissa,
IEEEX_Model_Mantissa,
VAXFF_Model_Mantissa,
VAXDF_Model_Mantissa,
VAXGF_Model_Mantissa);
-----------------
-- Model_Small --
-----------------
when Attribute_Model_Small =>
Float_Attribute_Universal_Real (
IEEES_Model_Small'Universal_Literal_String,
IEEEL_Model_Small'Universal_Literal_String,
IEEEX_Model_Small'Universal_Literal_String,
VAXFF_Model_Small'Universal_Literal_String,
VAXDF_Model_Small'Universal_Literal_String,
VAXGF_Model_Small'Universal_Literal_String);
-------------
-- Modulus --
-------------
when Attribute_Modulus =>
Fold_Uint (N, Modulus (P_Type));
--------------------
-- Null_Parameter --
--------------------
-- Cannot fold, we know the value sort of, but the whole point is
-- that there is no way to talk about this imaginary value except
-- by using the attribute, so we leave it the way it is.
when Attribute_Null_Parameter =>
null;
-----------------
-- Object_Size --
-----------------
-- The Object_Size attribute for a type returns the Esize of the
-- type and can be folded if this value is known.
when Attribute_Object_Size => Object_Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if Known_Esize (P_TypeA) then
Fold_Uint (N, Esize (P_TypeA));
end if;
end Object_Size;
-------------------------
-- Passed_By_Reference --
-------------------------
-- Scalar types are never passed by reference
when Attribute_Passed_By_Reference =>
Fold_Uint (N, False_Value);
---------
-- Pos --
---------
when Attribute_Pos =>
Fold_Uint (N, Expr_Value (E1));
----------
-- Pred --
----------
when Attribute_Pred => Pred :
begin
if Static then
-- Floating-point case. For now, do not fold this, since we
-- don't know how to do it right (see fixed bug 3512-001 ???)
if Is_Floating_Point_Type (P_Type) then
Fold_Ureal (N,
Eval_Fat.Pred (P_Root_Type, Expr_Value_R (E1)));
-- Fixed-point case
elsif Is_Fixed_Point_Type (P_Type) then
Fold_Ureal (N,
Expr_Value_R (E1) - Small_Value (P_Type));
-- Modular integer case (wraps)
elsif Is_Modular_Integer_Type (P_Type) then
Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type));
-- Other scalar cases
else
pragma Assert (Is_Scalar_Type (P_Type));
if Is_Enumeration_Type (P_Type)
and then Expr_Value (E1) =
Expr_Value (Type_Low_Bound (P_Base_Type))
then
Apply_Compile_Time_Constraint_Error
(N, "Pred of type''First");
Check_Expressions;
return;
end if;
Fold_Uint (N, Expr_Value (E1) - 1);
end if;
end if;
end Pred;
-----------
-- Range --
-----------
-- No processing required, because by this stage, Range has been
-- replaced by First .. Last, so this branch can never be taken.
when Attribute_Range =>
raise Program_Error;
------------------
-- Range_Length --
------------------
when Attribute_Range_Length =>
Set_Bounds;
if Compile_Time_Known_Value (Hi_Bound)
and then Compile_Time_Known_Value (Lo_Bound)
then
Fold_Uint (N,
UI_Max
(0, Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound) + 1));
end if;
---------------
-- Remainder --
---------------
when Attribute_Remainder =>
if Static then
Fold_Ureal (N,
Eval_Fat.Remainder
(P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)));
end if;
-----------
-- Round --
-----------
when Attribute_Round => Round :
declare
Sr : Ureal;
Si : Uint;
begin
if Static then
-- First we get the (exact result) in units of small
Sr := Expr_Value_R (E1) / Small_Value (C_Type);
-- Now round that exactly to an integer
Si := UR_To_Uint (Sr);
-- Finally the result is obtained by converting back to real
Fold_Ureal (N, Si * Small_Value (C_Type));
end if;
end Round;
--------------
-- Rounding --
--------------
when Attribute_Rounding =>
if Static then
Fold_Ureal (N,
Eval_Fat.Rounding (P_Root_Type, Expr_Value_R (E1)));
end if;
---------------
-- Safe_Emax --
---------------
when Attribute_Safe_Emax =>
Float_Attribute_Universal_Integer (
IEEES_Safe_Emax,
IEEEL_Safe_Emax,
IEEEX_Safe_Emax,
VAXFF_Safe_Emax,
VAXDF_Safe_Emax,
VAXGF_Safe_Emax);
----------------
-- Safe_First --
----------------
when Attribute_Safe_First =>
Float_Attribute_Universal_Real (
IEEES_Safe_First'Universal_Literal_String,
IEEEL_Safe_First'Universal_Literal_String,
IEEEX_Safe_First'Universal_Literal_String,
VAXFF_Safe_First'Universal_Literal_String,
VAXDF_Safe_First'Universal_Literal_String,
VAXGF_Safe_First'Universal_Literal_String);
----------------
-- Safe_Large --
----------------
when Attribute_Safe_Large =>
if Is_Fixed_Point_Type (P_Type) then
Fold_Ureal (N, Expr_Value_R (Type_High_Bound (P_Base_Type)));
else
Float_Attribute_Universal_Real (
IEEES_Safe_Large'Universal_Literal_String,
IEEEL_Safe_Large'Universal_Literal_String,
IEEEX_Safe_Large'Universal_Literal_String,
VAXFF_Safe_Large'Universal_Literal_String,
VAXDF_Safe_Large'Universal_Literal_String,
VAXGF_Safe_Large'Universal_Literal_String);
end if;
---------------
-- Safe_Last --
---------------
when Attribute_Safe_Last =>
Float_Attribute_Universal_Real (
IEEES_Safe_Last'Universal_Literal_String,
IEEEL_Safe_Last'Universal_Literal_String,
IEEEX_Safe_Last'Universal_Literal_String,
VAXFF_Safe_Last'Universal_Literal_String,
VAXDF_Safe_Last'Universal_Literal_String,
VAXGF_Safe_Last'Universal_Literal_String);
----------------
-- Safe_Small --
----------------
when Attribute_Safe_Small =>
-- In Ada 95, the old Ada 83 attribute Safe_Small is redundant
-- for fixed-point, since is the same as Small, but we implement
-- it for backwards compatibility.
if Is_Fixed_Point_Type (P_Type) then
Fold_Ureal (N, Small_Value (P_Type));
-- Ada 83 Safe_Small for floating-point cases
else
Float_Attribute_Universal_Real (
IEEES_Safe_Small'Universal_Literal_String,
IEEEL_Safe_Small'Universal_Literal_String,
IEEEX_Safe_Small'Universal_Literal_String,
VAXFF_Safe_Small'Universal_Literal_String,
VAXDF_Safe_Small'Universal_Literal_String,
VAXGF_Safe_Small'Universal_Literal_String);
end if;
-----------
-- Scale --
-----------
when Attribute_Scale =>
Fold_Uint (N, Scale_Value (P_Type));
-------------
-- Scaling --
-------------
when Attribute_Scaling =>
if Static then
Fold_Ureal (N,
Eval_Fat.Scaling
(P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)));
end if;
------------------
-- Signed_Zeros --
------------------
when Attribute_Signed_Zeros =>
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)));
----------
-- Size --
----------
-- Size attribute returns the RM size. All scalar types can be folded,
-- as well as any types for which the size is known by the front end,
-- including any type for which a size attribute is specified.
when Attribute_Size | Attribute_VADS_Size => Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if RM_Size (P_TypeA) /= Uint_0 then
-- VADS_Size case
if (Id = Attribute_VADS_Size or else Use_VADS_Size) then
declare
S : constant Node_Id := Size_Clause (P_TypeA);
begin
-- If a size clause applies, then use the size from it.
-- This is one of the rare cases where we can use the
-- Size_Clause field for a subtype when Has_Size_Clause
-- is False. Consider:
-- type x is range 1 .. 64;
-- for x'size use 12;
-- subtype y is x range 0 .. 3;
-- Here y has a size clause inherited from x, but normally
-- it does not apply, and y'size is 2. However, y'VADS_Size
-- is indeed 12 and not 2.
if Present (S)
and then Is_OK_Static_Expression (Expression (S))
then
Fold_Uint (N, Expr_Value (Expression (S)));
-- If no size is specified, then we simply use the object
-- size in the VADS_Size case (e.g. Natural'Size is equal
-- to Integer'Size, not one less).
else
Fold_Uint (N, Esize (P_TypeA));
end if;
end;
-- Normal case (Size) in which case we want the RM_Size
else
Fold_Uint (N, RM_Size (P_TypeA));
end if;
end if;
end Size;
-----------
-- Small --
-----------
when Attribute_Small =>
-- The floating-point case is present only for Ada 83 compatibility.
-- Note that strictly this is an illegal addition, since we are
-- extending an Ada 95 defined attribute, but we anticipate an
-- ARG ruling that will permit this.
if Is_Floating_Point_Type (P_Type) then
-- Ada 83 attribute is defined as (RM83 3.5.8)
-- T'Small = 2.0**(-T'Emax - 1)
-- where
-- T'Emax = 4 * T'Mantissa
Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1));
-- Normal Ada 95 fixed-point case
else
Fold_Ureal (N, Small_Value (P_Type));
end if;
----------
-- Succ --
----------
when Attribute_Succ => Succ :
begin
if Static then
-- Floating-point case. For now, do not fold this, since we
-- don't know how to do it right (see fixed bug 3512-001 ???)
if Is_Floating_Point_Type (P_Type) then
Fold_Ureal (N,
Eval_Fat.Succ (P_Root_Type, Expr_Value_R (E1)));
-- Fixed-point case
elsif Is_Fixed_Point_Type (P_Type) then
Fold_Ureal (N,
Expr_Value_R (E1) + Small_Value (P_Type));
-- Modular integer case (wraps)
elsif Is_Modular_Integer_Type (P_Type) then
Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type));
-- Other scalar cases
else
pragma Assert (Is_Scalar_Type (P_Type));
if Is_Enumeration_Type (P_Type)
and then Expr_Value (E1) =
Expr_Value (Type_High_Bound (P_Base_Type))
then
Apply_Compile_Time_Constraint_Error
(N, "Succ of type''Last");
Check_Expressions;
return;
else
Fold_Uint (N, Expr_Value (E1) + 1);
end if;
end if;
end if;
end Succ;
----------------
-- Truncation --
----------------
when Attribute_Truncation =>
if Static then
Fold_Ureal (N,
Eval_Fat.Truncation (P_Root_Type, Expr_Value_R (E1)));
end if;
----------------
-- Type_Class --
----------------
when Attribute_Type_Class => Type_Class : declare
Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
Id : RE_Id;
begin
if Is_RTE (P_Root_Type, RE_Address) then
Id := RE_Type_Class_Address;
elsif Is_Enumeration_Type (Typ) then
Id := RE_Type_Class_Enumeration;
elsif Is_Integer_Type (Typ) then
Id := RE_Type_Class_Integer;
elsif Is_Fixed_Point_Type (Typ) then
Id := RE_Type_Class_Fixed_Point;
elsif Is_Floating_Point_Type (Typ) then
Id := RE_Type_Class_Floating_Point;
elsif Is_Array_Type (Typ) then
Id := RE_Type_Class_Array;
elsif Is_Record_Type (Typ) then
Id := RE_Type_Class_Record;
elsif Is_Access_Type (Typ) then
Id := RE_Type_Class_Access;
elsif Is_Enumeration_Type (Typ) then
Id := RE_Type_Class_Enumeration;
elsif Is_Task_Type (Typ) then
Id := RE_Type_Class_Task;
-- We treat protected types like task types. It would make more
-- sense to have another enumeration value, but after all the
-- whole point of this feature is to be exactly DEC compatible,
-- and changing the type Type_Clas would not meet this requirement.
elsif Is_Protected_Type (Typ) then
Id := RE_Type_Class_Task;
-- Not clear if there are any other possibilities, but if there
-- are, then we will treat them as the address case.
else
Id := RE_Type_Class_Address;
end if;
Rewrite (N, New_Occurrence_Of (RTE (Id), Loc));
end Type_Class;
-----------------------
-- Unbiased_Rounding --
-----------------------
when Attribute_Unbiased_Rounding =>
if Static then
Fold_Ureal (N,
Eval_Fat.Unbiased_Rounding (P_Root_Type, Expr_Value_R (E1)));
end if;
---------------
-- VADS_Size --
---------------
-- Processing is shared with Size
---------
-- Val --
---------
when Attribute_Val => Val :
begin
if Static then
if Expr_Value (E1) < Expr_Value (Type_Low_Bound (P_Base_Type))
or else
Expr_Value (E1) > Expr_Value (Type_High_Bound (P_Base_Type))
then
Apply_Compile_Time_Constraint_Error
(N, "Val expression out of range");
Check_Expressions;
return;
else
Fold_Uint (N, Expr_Value (E1));
end if;
end if;
end Val;
----------------
-- Value_Size --
----------------
-- The Value_Size attribute for a type returns the RM size of the
-- type. This an always be folded for scalar types, and can also
-- be folded for non-scalar types if the size is set.
when Attribute_Value_Size => Value_Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if RM_Size (P_TypeA) /= Uint_0 then
Fold_Uint (N, RM_Size (P_TypeA));
end if;
end Value_Size;
-------------
-- Version --
-------------
-- Version can never be static
when Attribute_Version =>
null;
----------------
-- Wide_Image --
----------------
-- Wide_Image is a scalar attribute, but is never static, because it
-- is not a static function (having a non-scalar argument (RM 4.9(22))
when Attribute_Wide_Image =>
null;
----------------
-- Wide_Width --
----------------
-- Processing for Wide_Width is combined with Width
-----------
-- Width --
-----------
-- This processing also handles the case of Wide_Width
when Attribute_Width | Attribute_Wide_Width => Width :
begin
if Static then
-- Floating-point types
if Is_Floating_Point_Type (P_Type) then
-- Width is zero for a null range (RM 3.5 (38))
if Expr_Value_R (Type_High_Bound (P_Type)) <
Expr_Value_R (Type_Low_Bound (P_Type))
then
Fold_Uint (N, Uint_0);
else
-- For floating-point, we have +N.dddE+nnn where length
-- of ddd is determined by type'Digits - 1, but is one
-- if Digits is one (RM 3.5 (33)).
-- nnn is set to 2 for Short_Float and Float (32 bit
-- floats), and 3 for Long_Float and Long_Long_Float.
-- This is not quite right, but is good enough.
declare
Len : Int :=
Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
begin
if Esize (P_Type) <= 32 then
Len := Len + 6;
else
Len := Len + 7;
end if;
Fold_Uint (N, UI_From_Int (Len));
end;
end if;
-- Fixed-point types
elsif Is_Fixed_Point_Type (P_Type) then
-- Width is zero for a null range (RM 3.5 (38))
if Expr_Value (Type_High_Bound (P_Type)) <
Expr_Value (Type_Low_Bound (P_Type))
then
Fold_Uint (N, Uint_0);
-- The non-null case depends on the specific real type
else
-- For fixed-point type width is Fore + 1 + Aft (RM 3.5(34))
Fold_Uint (N, UI_From_Int (Fore_Value + 1 + Aft_Value));
end if;
-- Discrete types
else
declare
R : constant Entity_Id := Root_Type (P_Type);
Lo : constant Uint :=
Expr_Value (Type_Low_Bound (P_Type));
Hi : constant Uint :=
Expr_Value (Type_High_Bound (P_Type));
W : Nat;
Wt : Nat;
T : Uint;
L : Node_Id;
C : Character;
begin
-- Empty ranges
if Lo > Hi then
W := 0;
-- Width for types derived from Standard.Character
-- and Standard.Wide_Character.
elsif R = Standard_Character
or else R = Standard_Wide_Character
then
W := 0;
-- Set W larger if needed
for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
-- Assume all wide-character escape sequences are
-- same length, so we can quit when we reach one.
if J > 255 then
if Id = Attribute_Wide_Width then
W := Int'Max (W, 3);
exit;
else
W := Int'Max (W, Length_Wide);
exit;
end if;
else
C := Character'Val (J);
-- Test for all cases where Character'Image
-- yields an image that is longer than three
-- characters. First the cases of Reserved_xxx
-- names (length = 12).
case C is
when Reserved_128 | Reserved_129 |
Reserved_132 | Reserved_153
=> Wt := 12;
when BS | HT | LF | VT | FF | CR |
SO | SI | EM | FS | GS | RS |
US | RI | MW | ST | PM
=> Wt := 2;
when NUL | SOH | STX | ETX | EOT |
ENQ | ACK | BEL | DLE | DC1 |
DC2 | DC3 | DC4 | NAK | SYN |
ETB | CAN | SUB | ESC | DEL |
BPH | NBH | NEL | SSA | ESA |
HTS | HTJ | VTS | PLD | PLU |
SS2 | SS3 | DCS | PU1 | PU2 |
STS | CCH | SPA | EPA | SOS |
SCI | CSI | OSC | APC
=> Wt := 3;
when Space .. Tilde |
No_Break_Space .. LC_Y_Diaeresis
=> Wt := 3;
end case;
W := Int'Max (W, Wt);
end if;
end loop;
-- Width for types derived from Standard.Boolean
elsif R = Standard_Boolean then
if Lo = 0 then
W := 5; -- FALSE
else
W := 4; -- TRUE
end if;
-- Width for integer types
elsif Is_Integer_Type (P_Type) then
T := UI_Max (abs Lo, abs Hi);
W := 2;
while T >= 10 loop
W := W + 1;
T := T / 10;
end loop;
-- Only remaining possibility is user declared enum type
else
pragma Assert (Is_Enumeration_Type (P_Type));
W := 0;
L := First_Literal (P_Type);
while Present (L) loop
-- Only pay attention to in range characters
if Lo <= Enumeration_Pos (L)
and then Enumeration_Pos (L) <= Hi
then
-- For Width case, use decoded name
if Id = Attribute_Width then
Get_Decoded_Name_String (Chars (L));
Wt := Nat (Name_Len);
-- For Wide_Width, use encoded name, and then
-- adjust for the encoding.
else
Get_Name_String (Chars (L));
-- Character literals are always of length 3
if Name_Buffer (1) = 'Q' then
Wt := 3;
-- Otherwise loop to adjust for upper/wide chars
else
Wt := Nat (Name_Len);
for J in 1 .. Name_Len loop
if Name_Buffer (J) = 'U' then
Wt := Wt - 2;
elsif Name_Buffer (J) = 'W' then
Wt := Wt - 4;
end if;
end loop;
end if;
end if;
W := Int'Max (W, Wt);
end if;
Next_Literal (L);
end loop;
end if;
Fold_Uint (N, UI_From_Int (W));
end;
end if;
end if;
end Width;
-- The following attributes can never be folded, and furthermore we
-- should not even have entered the case statement for any of these.
-- Note that in some cases, the values have already been folded as
-- a result of the processing in Analyze_Attribute.
when Attribute_Abort_Signal |
Attribute_Access |
Attribute_Address |
Attribute_Address_Size |
Attribute_Asm_Input |
Attribute_Asm_Output |
Attribute_Base |
Attribute_Bit_Order |
Attribute_Bit_Position |
Attribute_Callable |
Attribute_Caller |
Attribute_Class |
Attribute_Code_Address |
Attribute_Count |
Attribute_Default_Bit_Order |
Attribute_Elaborated |
Attribute_Elab_Body |
Attribute_Elab_Spec |
Attribute_External_Tag |
Attribute_First_Bit |
Attribute_Input |
Attribute_Last_Bit |
Attribute_Max_Interrupt_Priority |
Attribute_Max_Priority |
Attribute_Maximum_Alignment |
Attribute_Output |
Attribute_Partition_ID |
Attribute_Position |
Attribute_Read |
Attribute_Storage_Pool |
Attribute_Storage_Size |
Attribute_Storage_Unit |
Attribute_Tag |
Attribute_Terminated |
Attribute_Tick |
Attribute_To_Address |
Attribute_UET_Address |
Attribute_Unchecked_Access |
Attribute_Universal_Literal_String |
Attribute_Unrestricted_Access |
Attribute_Valid |
Attribute_Value |
Attribute_Wchar_T_Size |
Attribute_Wide_Value |
Attribute_Word_Size |
Attribute_Write =>
raise Program_Error;
end case;
-- At the end of the case, one more check. If we did a static evaluation
-- so that the result is now a literal, then set Is_Static_Expression
-- in the constant only if the prefix type is a static subtype. For
-- non-static subtypes, the folding is still OK, but not static.
if Nkind (N) = N_Integer_Literal
or else Nkind (N) = N_Real_Literal
or else Nkind (N) = N_Character_Literal
or else Nkind (N) = N_String_Literal
or else (Is_Entity_Name (N)
and then Ekind (Entity (N)) = E_Enumeration_Literal)
then
Set_Is_Static_Expression (N, Static);
-- If this is still an attribute reference, then it has not been folded
-- and that means that its expressions are in a non-static context.
elsif Nkind (N) = N_Attribute_Reference then
Check_Expressions;
-- Note: the else case not covered here are odd cases where the
-- processing has transformed the attribute into something other
-- than a constant. Nothing more to do in such cases.
else
null;
end if;
end Eval_Attribute;
------------------------------
-- Is_Anonymous_Tagged_Base --
------------------------------
function Is_Anonymous_Tagged_Base
(Anon : Entity_Id;
Typ : Entity_Id)
return Boolean
is
begin
return
Anon = Current_Scope
and then Is_Itype (Anon)
and then Associated_Node_For_Itype (Anon) = Parent (Typ);
end Is_Anonymous_Tagged_Base;
-----------------------
-- Resolve_Attribute --
-----------------------
procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is
Loc : constant Source_Ptr := Sloc (N);
P : constant Node_Id := Prefix (N);
Aname : constant Name_Id := Attribute_Name (N);
Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
Index : Interp_Index;
It : Interp;
Btyp : Entity_Id := Base_Type (Typ);
Nom_Subt : Entity_Id;
begin
-- If error during analysis, no point in continuing, except for
-- array types, where we get better recovery by using unconstrained
-- indices than nothing at all (see Check_Array_Type).
if Error_Posted (N)
and then Attr_Id /= Attribute_First
and then Attr_Id /= Attribute_Last
and then Attr_Id /= Attribute_Length
and then Attr_Id /= Attribute_Range
then
return;
end if;
-- If attribute was universal type, reset to actual type
if Etype (N) = Universal_Integer
or else Etype (N) = Universal_Real
then
Set_Etype (N, Typ);
end if;
-- Remaining processing depends on attribute
case Attr_Id is
------------
-- Access --
------------
-- For access attributes, if the prefix denotes an entity, it is
-- interpreted as a name, never as a call. It may be overloaded,
-- in which case resolution uses the profile of the context type.
-- Otherwise prefix must be resolved.
when Attribute_Access
| Attribute_Unchecked_Access
| Attribute_Unrestricted_Access =>
if Is_Variable (P) then
Note_Possible_Modification (P);
end if;
if Is_Entity_Name (P) then
if Is_Overloaded (P) then
Get_First_Interp (P, Index, It);
while Present (It.Nam) loop
if Type_Conformant (Designated_Type (Typ), It.Nam) then
Set_Entity (P, It.Nam);
-- The prefix is definitely NOT overloaded anymore
-- at this point, so we reset the Is_Overloaded
-- flag to avoid any confusion when reanalyzing
-- the node.
Set_Is_Overloaded (P, False);
Generate_Reference (Entity (P), P);
exit;
end if;
Get_Next_Interp (Index, It);
end loop;
-- If it is a subprogram name or a type, there is nothing
-- to resolve.
elsif not Is_Overloadable (Entity (P))
and then not Is_Type (Entity (P))
then
Resolve (P, Etype (P));
end if;
if not Is_Entity_Name (P) then
null;
elsif Is_Abstract (Entity (P))
and then Is_Overloadable (Entity (P))
then
Error_Msg_Name_1 := Aname;
Error_Msg_N ("prefix of % attribute cannot be abstract", P);
Set_Etype (N, Any_Type);
elsif Convention (Entity (P)) = Convention_Intrinsic then
Error_Msg_Name_1 := Aname;
if Ekind (Entity (P)) = E_Enumeration_Literal then
Error_Msg_N
("prefix of % attribute cannot be enumeration literal",
P);
else
Error_Msg_N
("prefix of % attribute cannot be intrinsic", P);
end if;
Set_Etype (N, Any_Type);
end if;
-- Assignments, return statements, components of aggregates,
-- generic instantiations will require convention checks if
-- the type is an access to subprogram. Given that there will
-- also be accessibility checks on those, this is where the
-- checks can eventually be centralized ???
if Ekind (Btyp) = E_Access_Subprogram_Type then
if Convention (Btyp) /= Convention (Entity (P)) then
Error_Msg_N
("subprogram has invalid convention for context", P);
else
Check_Subtype_Conformant
(New_Id => Entity (P),
Old_Id => Designated_Type (Btyp),
Err_Loc => P);
end if;
if Attr_Id = Attribute_Unchecked_Access then
Error_Msg_Name_1 := Aname;
Error_Msg_N
("attribute% cannot be applied to a subprogram", P);
elsif Aname = Name_Unrestricted_Access then
null; -- Nothing to check
-- Check the static accessibility rule of 3.10.2(32)
elsif Attr_Id = Attribute_Access
and then Subprogram_Access_Level (Entity (P))
> Type_Access_Level (Btyp)
then
if not In_Instance_Body then
Error_Msg_N
("subprogram must not be deeper than access type",
P);
else
Warn_On_Instance := True;
Error_Msg_N
("subprogram must not be deeper than access type?",
P);
Error_Msg_N
("Constraint_Error will be raised ?", P);
Set_Raises_Constraint_Error (N);
Warn_On_Instance := False;
end if;
-- Check the restriction of 3.10.2(32) that disallows
-- the type of the access attribute to be declared
-- outside a generic body when the attribute occurs
-- within that generic body.
elsif Enclosing_Generic_Body (Entity (P))
/= Enclosing_Generic_Body (Btyp)
then
Error_Msg_N
("access type must not be outside generic body", P);
end if;
end if;
-- if this is a renaming, an inherited operation, or a
-- subprogram instance, use the original entity.
if Is_Entity_Name (P)
and then Is_Overloadable (Entity (P))
and then Present (Alias (Entity (P)))
then
Rewrite (P,
New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
end if;
elsif Nkind (P) = N_Selected_Component
and then Is_Overloadable (Entity (Selector_Name (P)))
then
-- Protected operation. If operation is overloaded, must
-- disambiguate. Prefix that denotes protected object itself
-- is resolved with its own type.
if Attr_Id = Attribute_Unchecked_Access then
Error_Msg_Name_1 := Aname;
Error_Msg_N
("attribute% cannot be applied to protected operation", P);
end if;
Resolve (Prefix (P), Etype (Prefix (P)));
elsif Is_Overloaded (P) then
-- Use the designated type of the context to disambiguate.
declare
Index : Interp_Index;
It : Interp;
begin
Get_First_Interp (P, Index, It);
while Present (It.Typ) loop
if Covers (Designated_Type (Typ), It.Typ) then
Resolve (P, It.Typ);
exit;
end if;
Get_Next_Interp (Index, It);
end loop;
end;
else
Resolve (P, Etype (P));
end if;
-- X'Access is illegal if X denotes a constant and the access
-- type is access-to-variable. Same for 'Unchecked_Access.
-- The rule does not apply to 'Unrestricted_Access.
if not (Ekind (Btyp) = E_Access_Subprogram_Type
or else (Is_Record_Type (Btyp) and then
Present (Corresponding_Remote_Type (Btyp)))
or else Ekind (Btyp) = E_Access_Protected_Subprogram_Type
or else Is_Access_Constant (Btyp)
or else Is_Variable (P)
or else Attr_Id = Attribute_Unrestricted_Access)
then
if Comes_From_Source (N) then
Error_Msg_N ("access-to-variable designates constant", P);
end if;
end if;
if (Attr_Id = Attribute_Access
or else
Attr_Id = Attribute_Unchecked_Access)
and then (Ekind (Btyp) = E_General_Access_Type
or else Ekind (Btyp) = E_Anonymous_Access_Type)
then
if Is_Dependent_Component_Of_Mutable_Object (P) then
Error_Msg_N
("illegal attribute for discriminant-dependent component",
P);
end if;
-- Check the static matching rule of 3.10.2(27). The
-- nominal subtype of the prefix must statically
-- match the designated type.
Nom_Subt := Etype (P);
if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then
Nom_Subt := Etype (Nom_Subt);
end if;
if Is_Tagged_Type (Designated_Type (Typ)) then
-- If the attribute is in the context of an access
-- parameter, then the prefix is allowed to be of
-- the class-wide type (by AI-127).
if Ekind (Typ) = E_Anonymous_Access_Type then
if not Covers (Designated_Type (Typ), Nom_Subt)
and then not Covers (Nom_Subt, Designated_Type (Typ))
then
declare
Desig : Entity_Id;
begin
Desig := Designated_Type (Typ);
if Is_Class_Wide_Type (Desig) then
Desig := Etype (Desig);
end if;
if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then
null;
else
Error_Msg_NE
("type of prefix: & not compatible",
P, Nom_Subt);
Error_Msg_NE
("\with &, the expected designated type",
P, Designated_Type (Typ));
end if;
end;
end if;
elsif not Covers (Designated_Type (Typ), Nom_Subt)
or else
(not Is_Class_Wide_Type (Designated_Type (Typ))
and then Is_Class_Wide_Type (Nom_Subt))
then
Error_Msg_NE
("type of prefix: & is not covered", P, Nom_Subt);
Error_Msg_NE
("\by &, the expected designated type" &
" ('R'M 3.10.2 (27))", P, Designated_Type (Typ));
end if;
if Is_Class_Wide_Type (Designated_Type (Typ))
and then Has_Discriminants (Etype (Designated_Type (Typ)))
and then Is_Constrained (Etype (Designated_Type (Typ)))
and then Designated_Type (Typ) /= Nom_Subt
then
Apply_Discriminant_Check
(N, Etype (Designated_Type (Typ)));
end if;
elsif not Subtypes_Statically_Match
(Designated_Type (Typ), Nom_Subt)
and then
not (Has_Discriminants (Designated_Type (Typ))
and then not Is_Constrained (Designated_Type (Typ)))
then
Error_Msg_N
("object subtype must statically match "
& "designated subtype", P);
if Is_Entity_Name (P)
and then Is_Array_Type (Designated_Type (Typ))
then
declare
D : constant Node_Id := Declaration_Node (Entity (P));
begin
Error_Msg_N ("aliased object has explicit bounds?",
D);
Error_Msg_N ("\declare without bounds"
& " (and with explicit initialization)?", D);
Error_Msg_N ("\for use with unconstrained access?", D);
end;
end if;
end if;
-- Check the static accessibility rule of 3.10.2(28).
-- Note that this check is not performed for the
-- case of an anonymous access type, since the access
-- attribute is always legal in such a context.
if Attr_Id /= Attribute_Unchecked_Access
and then Object_Access_Level (P) > Type_Access_Level (Btyp)
and then Ekind (Btyp) = E_General_Access_Type
then
-- In an instance, this is a runtime check, but one we
-- know will fail, so generate an appropriate warning.
if In_Instance_Body then
Error_Msg_N
("?non-local pointer cannot point to local object", P);
Error_Msg_N
("?Program_Error will be raised at run time", P);
Rewrite (N, Make_Raise_Program_Error (Loc));
Set_Etype (N, Typ);
return;
else
Error_Msg_N
("non-local pointer cannot point to local object", P);
if Is_Record_Type (Current_Scope)
and then (Nkind (Parent (N)) =
N_Discriminant_Association
or else
Nkind (Parent (N)) =
N_Index_Or_Discriminant_Constraint)
then
declare
Indic : Node_Id := Parent (Parent (N));
begin
while Present (Indic)
and then Nkind (Indic) /= N_Subtype_Indication
loop
Indic := Parent (Indic);
end loop;
if Present (Indic) then
Error_Msg_NE
("\use an access definition for" &
" the access discriminant of&", N,
Entity (Subtype_Mark (Indic)));
end if;
end;
end if;
end if;
end if;
end if;
if Ekind (Btyp) = E_Access_Protected_Subprogram_Type
and then Is_Entity_Name (P)
and then not Is_Protected_Type (Scope (Entity (P)))
then
Error_Msg_N ("context requires a protected subprogram", P);
elsif Ekind (Btyp) = E_Access_Subprogram_Type
and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
then
Error_Msg_N ("context requires a non-protected subprogram", P);
end if;
-- The context cannot be a pool-specific type, but this is a
-- legality rule, not a resolution rule, so it must be checked
-- separately, after possibly disambiguation (see AI-245).
if Ekind (Btyp) = E_Access_Type
and then Attr_Id /= Attribute_Unrestricted_Access
then
Wrong_Type (N, Typ);
end if;
Set_Etype (N, Typ);
-- Check for incorrect atomic/volatile reference (RM C.6(12))
if Attr_Id /= Attribute_Unrestricted_Access then
if Is_Atomic_Object (P)
and then not Is_Atomic (Designated_Type (Typ))
then
Error_Msg_N
("access to atomic object cannot yield access-to-" &
"non-atomic type", P);
elsif Is_Volatile_Object (P)
and then not Is_Volatile (Designated_Type (Typ))
then
Error_Msg_N
("access to volatile object cannot yield access-to-" &
"non-volatile type", P);
end if;
end if;
-------------
-- Address --
-------------
-- Deal with resolving the type for Address attribute, overloading
-- is not permitted here, since there is no context to resolve it.
when Attribute_Address | Attribute_Code_Address =>
-- To be safe, assume that if the address of a variable is taken,
-- it may be modified via this address, so note modification.
if Is_Variable (P) then
Note_Possible_Modification (P);
end if;
if Nkind (P) in N_Subexpr
and then Is_Overloaded (P)
then
Get_First_Interp (P, Index, It);
Get_Next_Interp (Index, It);
if Present (It.Nam) then
Error_Msg_Name_1 := Aname;
Error_Msg_N
("prefix of % attribute cannot be overloaded", N);
return;
end if;
end if;
if not Is_Entity_Name (P)
or else not Is_Overloadable (Entity (P))
then
if not Is_Task_Type (Etype (P))
or else Nkind (P) = N_Explicit_Dereference
then
Resolve (P, Etype (P));
end if;
end if;
-- If this is the name of a derived subprogram, or that of a
-- generic actual, the address is that of the original entity.
if Is_Entity_Name (P)
and then Is_Overloadable (Entity (P))
and then Present (Alias (Entity (P)))
then
Rewrite (P,
New_Occurrence_Of (Alias (Entity (P)), Sloc (P)));
end if;
---------------
-- AST_Entry --
---------------
-- Prefix of the AST_Entry attribute is an entry name which must
-- not be resolved, since this is definitely not an entry call.
when Attribute_AST_Entry =>
null;
------------------
-- Body_Version --
------------------
-- Prefix of Body_Version attribute can be a subprogram name which
-- must not be resolved, since this is not a call.
when Attribute_Body_Version =>
null;
------------
-- Caller --
------------
-- Prefix of Caller attribute is an entry name which must not
-- be resolved, since this is definitely not an entry call.
when Attribute_Caller =>
null;
------------------
-- Code_Address --
------------------
-- Shares processing with Address attribute
-----------
-- Count --
-----------
-- Prefix of the Count attribute is an entry name which must not
-- be resolved, since this is definitely not an entry call.
when Attribute_Count =>
null;
----------------
-- Elaborated --
----------------
-- Prefix of the Elaborated attribute is a subprogram name which
-- must not be resolved, since this is definitely not a call. Note
-- that it is a library unit, so it cannot be overloaded here.
when Attribute_Elaborated =>
null;
--------------------
-- Mechanism_Code --
--------------------
-- Prefix of the Mechanism_Code attribute is a function name
-- which must not be resolved. Should we check for overloaded ???
when Attribute_Mechanism_Code =>
null;
------------------
-- Partition_ID --
------------------
-- Most processing is done in sem_dist, after determining the
-- context type. Node is rewritten as a conversion to a runtime call.
when Attribute_Partition_ID =>
Process_Partition_Id (N);
return;
-----------
-- Range --
-----------
-- We replace the Range attribute node with a range expression
-- whose bounds are the 'First and 'Last attributes applied to the
-- same prefix. The reason that we do this transformation here
-- instead of in the expander is that it simplifies other parts of
-- the semantic analysis which assume that the Range has been
-- replaced; thus it must be done even when in semantic-only mode
-- (note that the RM specifically mentions this equivalence, we
-- take care that the prefix is only evaluated once).
when Attribute_Range => Range_Attribute :
declare
LB : Node_Id;
HB : Node_Id;
function Check_Discriminated_Prival
(N : Node_Id)
return Node_Id;
-- The range of a private component constrained by a
-- discriminant is rewritten to make the discriminant
-- explicit. This solves some complex visibility problems
-- related to the use of privals.
function Check_Discriminated_Prival
(N : Node_Id)
return Node_Id
is
begin
if Is_Entity_Name (N)
and then Ekind (Entity (N)) = E_In_Parameter
and then not Within_Init_Proc
then
return Make_Identifier (Sloc (N), Chars (Entity (N)));
else
return Duplicate_Subexpr (N);
end if;
end Check_Discriminated_Prival;
-- Start of processing for Range_Attribute
begin
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
then
Resolve (P, Etype (P));
end if;
-- Check whether prefix is (renaming of) private component
-- of protected type.
if Is_Entity_Name (P)
and then Comes_From_Source (N)
and then Is_Array_Type (Etype (P))
and then Number_Dimensions (Etype (P)) = 1
and then (Ekind (Scope (Entity (P))) = E_Protected_Type
or else
Ekind (Scope (Scope (Entity (P)))) =
E_Protected_Type)
then
LB := Check_Discriminated_Prival (
Type_Low_Bound (Etype (First_Index (Etype (P)))));
HB := Check_Discriminated_Prival (
Type_High_Bound (Etype (First_Index (Etype (P)))));
else
HB :=
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (P),
Attribute_Name => Name_Last,
Expressions => Expressions (N));
LB :=
Make_Attribute_Reference (Loc,
Prefix => P,
Attribute_Name => Name_First,
Expressions => Expressions (N));
end if;
-- If the original was marked as Must_Not_Freeze (see code
-- in Sem_Ch3.Make_Index), then make sure the rewriting
-- does not freeze either.
if Must_Not_Freeze (N) then
Set_Must_Not_Freeze (HB);
Set_Must_Not_Freeze (LB);
Set_Must_Not_Freeze (Prefix (HB));
Set_Must_Not_Freeze (Prefix (LB));
end if;
if Raises_Constraint_Error (Prefix (N)) then
-- Preserve Sloc of prefix in the new bounds, so that
-- the posted warning can be removed if we are within
-- unreachable code.
Set_Sloc (LB, Sloc (Prefix (N)));
Set_Sloc (HB, Sloc (Prefix (N)));
end if;
Rewrite (N, Make_Range (Loc, LB, HB));
Analyze_And_Resolve (N, Typ);
-- Normally after resolving attribute nodes, Eval_Attribute
-- is called to do any possible static evaluation of the node.
-- However, here since the Range attribute has just been
-- transformed into a range expression it is no longer an
-- attribute node and therefore the call needs to be avoided
-- and is accomplished by simply returning from the procedure.
return;
end Range_Attribute;
-----------------
-- UET_Address --
-----------------
-- Prefix must not be resolved in this case, since it is not a
-- real entity reference. No action of any kind is require!
when Attribute_UET_Address =>
return;
----------------------
-- Unchecked_Access --
----------------------
-- Processing is shared with Access
-------------------------
-- Unrestricted_Access --
-------------------------
-- Processing is shared with Access
---------
-- Val --
---------
-- Apply range check. Note that we did not do this during the
-- analysis phase, since we wanted Eval_Attribute to have a
-- chance at finding an illegal out of range value.
when Attribute_Val =>
-- Note that we do our own Eval_Attribute call here rather than
-- use the common one, because we need to do processing after
-- the call, as per above comment.
Eval_Attribute (N);
-- Eval_Attribute may replace the node with a raise CE, or
-- fold it to a constant. Obviously we only apply a scalar
-- range check if this did not happen!
if Nkind (N) = N_Attribute_Reference
and then Attribute_Name (N) = Name_Val
then
Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
end if;
return;
-------------
-- Version --
-------------
-- Prefix of Version attribute can be a subprogram name which
-- must not be resolved, since this is not a call.
when Attribute_Version =>
null;
----------------------
-- Other Attributes --
----------------------
-- For other attributes, resolve prefix unless it is a type. If
-- the attribute reference itself is a type name ('Base and 'Class)
-- then this is only legal within a task or protected record.
when others =>
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
then
Resolve (P, Etype (P));
end if;
-- If the attribute reference itself is a type name ('Base,
-- 'Class) then this is only legal within a task or protected
-- record. What is this all about ???
if Is_Entity_Name (N)
and then Is_Type (Entity (N))
then
if Is_Concurrent_Type (Entity (N))
and then In_Open_Scopes (Entity (P))
then
null;
else
Error_Msg_N
("invalid use of subtype name in expression or call", N);
end if;
end if;
-- For attributes whose argument may be a string, complete
-- resolution of argument now. This avoids premature expansion
-- (and the creation of transient scopes) before the attribute
-- reference is resolved.
case Attr_Id is
when Attribute_Value =>
Resolve (First (Expressions (N)), Standard_String);
when Attribute_Wide_Value =>
Resolve (First (Expressions (N)), Standard_Wide_String);
when others => null;
end case;
end case;
-- Normally the Freezing is done by Resolve but sometimes the Prefix
-- is not resolved, in which case the freezing must be done now.
Freeze_Expression (P);
-- Finally perform static evaluation on the attribute reference
Eval_Attribute (N);
end Resolve_Attribute;
end Sem_Attr;