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gcc/gcc/ada/sem_attr.adb
Arnaud Charlet d6fd1f07ac [multiple changes] 
2017-05-02  Bob Duff  <duff@adacore.com>

	* sem_attr.adb (Attribute_Enum_Rep): Disallow T'Enum_Rep.

2017-05-02  Vasiliy Fofanov  <fofanov@adacore.com>

	* s-os_lib.ads: Minor typo fix.

2017-05-02  Vasiliy Fofanov  <fofanov@adacore.com>

	* gnatls.adb: Merge and refactor code from Prj.Env and remove
	this deprecated dependency.

2017-05-02  Ed Schonberg  <schonberg@adacore.com>

	* exp_util.ads: minor comment addition.

2017-05-02  Eric Botcazou  <ebotcazou@adacore.com>

	* sem_ch3.adb (Build_Derived_Record_Type): Fix a few typos and
	pastos in part #3 of the head comment.

2017-05-02  Ed Schonberg  <schonberg@adacore.com>

	* exp_ch3.adb (Freeze_Type): Do not generate an invariant
	procedure body for a local (sub)type declaration within a
	predicate function. Invariant checks do not apply to these, and
	the expansion of the procedure will happen in the wrong scope,
	leading to misplaced freeze nodes.

2017-05-02  Ed Schonberg  <schonberg@adacore.com>

	* exp_util.adb (Insert_Library_Level_Action): Use proper scope
	to analyze generated actions.  If the main unit is a body,
	the required scope is that of the corresponding unit declaration.

2017-05-02  Arnaud Charlet  <charlet@adacore.com>

	* einfo.adb (Declaration_Node): flip branches of
	an IF statement to avoid repeated negations in its condition;
	no change in semantics, only to improve readability.

From-SVN: r247480
2017-05-02 11:06:41 +02:00

11987 lines
395 KiB
Ada
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ A T T R --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2017, 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 3, 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 COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Characters.Latin_1; use Ada.Characters.Latin_1;
with Atree; use Atree;
with Casing; use Casing;
with Checks; use Checks;
with Debug; use Debug;
with Einfo; use Einfo;
with Elists; use Elists;
with Errout; use Errout;
with Eval_Fat;
with Exp_Dist; use Exp_Dist;
with Exp_Util; use Exp_Util;
with Expander; use Expander;
with Freeze; use Freeze;
with Gnatvsn; use Gnatvsn;
with Itypes; use Itypes;
with Lib; use Lib;
with Lib.Xref; use Lib.Xref;
with Nlists; use Nlists;
with Nmake; use Nmake;
with Opt; use Opt;
with Restrict; use Restrict;
with Rident; use Rident;
with Rtsfind; use Rtsfind;
with Sdefault; use Sdefault;
with Sem; use Sem;
with Sem_Aux; use Sem_Aux;
with Sem_Cat; use Sem_Cat;
with Sem_Ch6; use Sem_Ch6;
with Sem_Ch8; use Sem_Ch8;
with Sem_Ch10; use Sem_Ch10;
with Sem_Dim; use Sem_Dim;
with Sem_Dist; use Sem_Dist;
with Sem_Elab; use Sem_Elab;
with Sem_Elim; use Sem_Elim;
with Sem_Eval; use Sem_Eval;
with Sem_Prag; use Sem_Prag;
with Sem_Res; use Sem_Res;
with Sem_Type; use Sem_Type;
with Sem_Util; use Sem_Util;
with Sem_Warn;
with Stand; use Stand;
with Sinfo; use Sinfo;
with Sinput; use Sinput;
with System;
with Stringt; use Stringt;
with Style;
with Stylesw; use Stylesw;
with Targparm; use Targparm;
with Ttypes; use Ttypes;
with Tbuild; use Tbuild;
with Uintp; use Uintp;
with Uname; use Uname;
with Urealp; use Urealp;
with System.CRC32; use System.CRC32;
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.
-- In Ada 83 mode, these are the only recognized attributes. In other Ada
-- modes all these attributes are recognized, even if removed in Ada 95.
Attribute_83 : constant 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);
-- The following array is the list of attributes defined in the Ada 2005
-- RM which are not defined in Ada 95. These are recognized in Ada 95 mode,
-- but in Ada 95 they are considered to be implementation defined.
Attribute_05 : constant Attribute_Class_Array := Attribute_Class_Array'(
Attribute_Machine_Rounding |
Attribute_Mod |
Attribute_Priority |
Attribute_Stream_Size |
Attribute_Wide_Wide_Width => True,
others => False);
-- The following array is the list of attributes defined in the Ada 2012
-- RM which are not defined in Ada 2005. These are recognized in Ada 95
-- and Ada 2005 modes, but are considered to be implementation defined.
Attribute_12 : constant Attribute_Class_Array := Attribute_Class_Array'(
Attribute_First_Valid |
Attribute_Has_Same_Storage |
Attribute_Last_Valid |
Attribute_Max_Alignment_For_Allocation => True,
others => False);
-- The following array contains all attributes that imply a modification
-- of their prefixes or result in an access value. Such prefixes can be
-- considered as lvalues.
Attribute_Name_Implies_Lvalue_Prefix : constant Attribute_Class_Array :=
Attribute_Class_Array'(
Attribute_Access |
Attribute_Address |
Attribute_Input |
Attribute_Read |
Attribute_Unchecked_Access |
Attribute_Unrestricted_Access => 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
-- Expand_N_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.
procedure Set_Boolean_Result (N : Node_Id; B : Boolean);
-- Rewrites node N with an occurrence of either Standard_False or
-- Standard_True, depending on the value of the parameter B. The
-- result is marked as a static expression.
function Statically_Denotes_Object (N : Node_Id) return Boolean;
-- Predicate used to check the legality of the prefix to 'Loop_Entry and
-- 'Old, when the prefix is not an entity name. Current RM specfies that
-- the prefix must be a direct or expanded name, but it has been proposed
-- that the prefix be allowed to be a selected component that does not
-- depend on a discriminant, or an indexed component with static indices.
-- Current code for this predicate implements this more permissive
-- implementation.
-----------------------
-- 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
-----------------------
-- Local Subprograms --
-----------------------
procedure Address_Checks;
-- Semantic checks for valid use of Address attribute. This was made
-- a separate routine with the idea of using it for unrestricted access
-- which seems like it should follow the same rules, but that turned
-- out to be impractical. So now this is only used for Address.
procedure Analyze_Access_Attribute;
-- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
-- Internally, Id distinguishes which of the three cases is involved.
procedure Analyze_Attribute_Old_Result
(Legal : out Boolean;
Spec_Id : out Entity_Id);
-- Common processing for attributes 'Old and 'Result. The routine checks
-- that the attribute appears in a postcondition-like aspect or pragma
-- associated with a suitable subprogram or a body. Flag Legal is set
-- when the above criteria are met. Spec_Id denotes the entity of the
-- subprogram [body] or Empty if the attribute is illegal.
procedure Bad_Attribute_For_Predicate;
-- Output error message for use of a predicate (First, Last, Range) not
-- allowed with a type that has predicates. If the type is a generic
-- actual, then the message is a warning, and we generate code to raise
-- program error with an appropriate reason. No error message is given
-- for internally generated uses of the attributes. This legality rule
-- only applies to scalar types.
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 dereference, 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 of 'Image is an enumeration type, set all its
-- literals as referenced, since the image function could possibly end
-- up referencing any of the literals indirectly. Same for Enum_Val.
-- Set the flag only if the reference is in the main code unit. Same
-- restriction when resolving 'Value; otherwise an improperly set
-- reference when analyzing an inlined body will lose a proper
-- warning on a useless with_clause.
procedure Check_First_Last_Valid;
-- Perform all checks for First_Valid and Last_Valid attributes
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 Check_SPARK_05_Restriction_On_Attribute;
-- Issue an error in formal mode because attribute N is allowed
procedure Check_Integer_Type;
-- Verify that prefix of attribute N is an integer type
procedure Check_Modular_Integer_Type;
-- Verify that prefix of attribute N is a modular integer type
procedure Check_Not_CPP_Type;
-- Check that P (the prefix of the attribute) is not an CPP type
-- for which no Ada predefined primitive is available.
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 is an object reference
procedure Check_PolyORB_Attribute;
-- Validity checking for PolyORB/DSA attribute
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. Also checks
-- that there are no arguments.
procedure Check_Stream_Attribute (Nam : TSS_Name_Type);
-- Validity checking for stream attribute. Nam is the TSS name of the
-- corresponding possible defined attribute function (e.g. for the
-- Read attribute, Nam will be TSS_Stream_Read).
procedure Check_System_Prefix;
-- Verify that prefix of attribute N is package System
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
-- Elaborated) which can refer to non-visible unit.
procedure Error_Attr (Msg : String; Error_Node : Node_Id);
pragma No_Return (Error_Attr);
procedure Error_Attr;
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. The call with
-- no arguments is used when the caller has already generated the
-- required error messages.
procedure Error_Attr_P (Msg : String);
pragma No_Return (Error_Attr);
-- Like Error_Attr, but error is posted at the start of the prefix
procedure Legal_Formal_Attribute;
-- Common processing for attributes Definite and Has_Discriminants.
-- Checks that prefix is generic indefinite formal type.
procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
-- Common processing for attributes Max_Alignment_For_Allocation and
-- Max_Size_In_Storage_Elements.
procedure Min_Max;
-- Common processing for attributes Max and Min
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 which
-- is marked as static.
procedure Uneval_Old_Msg;
-- Called when Loop_Entry or Old is used in a potentially unevaluated
-- expression. Generates appropriate message or warning depending on
-- the setting of Opt.Uneval_Old (or flags in an N_Aspect_Specification
-- node in the aspect case).
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.
--------------------
-- Address_Checks --
--------------------
procedure Address_Checks is
begin
-- An Address attribute created by expansion is legal even when it
-- applies to other entity-denoting expressions.
if not Comes_From_Source (N) then
return;
-- Address attribute on a protected object self reference is legal
elsif Is_Protected_Self_Reference (P) then
return;
-- Address applied to an entity
elsif Is_Entity_Name (P) then
declare
Ent : constant Entity_Id := Entity (P);
begin
if Is_Subprogram (Ent) then
Set_Address_Taken (Ent);
Kill_Current_Values (Ent);
-- An Address attribute is accepted when generated by the
-- compiler for dispatching operation, and an error is
-- issued once the subprogram is frozen (to avoid confusing
-- errors about implicit uses of Address in the dispatch
-- table initialization).
if Has_Pragma_Inline_Always (Entity (P))
and then Comes_From_Source (P)
then
Error_Attr_P
("prefix of % attribute cannot be Inline_Always "
& "subprogram");
-- It is illegal to apply 'Address to an intrinsic
-- subprogram. This is now formalized in AI05-0095.
-- In an instance, an attempt to obtain 'Address of an
-- intrinsic subprogram (e.g the renaming of a predefined
-- operator that is an actual) raises Program_Error.
elsif Convention (Ent) = Convention_Intrinsic then
if In_Instance then
Rewrite (N,
Make_Raise_Program_Error (Loc,
Reason => PE_Address_Of_Intrinsic));
else
Error_Msg_Name_1 := Aname;
Error_Msg_N
("cannot take % of intrinsic subprogram", N);
end if;
-- Issue an error if prefix denotes an eliminated subprogram
else
Check_For_Eliminated_Subprogram (P, Ent);
end if;
-- Object or label reference
elsif Is_Object (Ent) or else Ekind (Ent) = E_Label then
Set_Address_Taken (Ent);
-- Deal with No_Implicit_Aliasing restriction
if Restriction_Check_Required (No_Implicit_Aliasing) then
if not Is_Aliased_View (P) then
Check_Restriction (No_Implicit_Aliasing, P);
else
Check_No_Implicit_Aliasing (P);
end if;
end if;
-- If we have an address of an object, and the attribute
-- comes from source, then set the object as potentially
-- source modified. We do this because the resulting address
-- can potentially be used to modify the variable and we
-- might not detect this, leading to some junk warnings.
Set_Never_Set_In_Source (Ent, False);
-- Allow Address to be applied to task or protected type,
-- returning null address (what is that about???)
elsif (Is_Concurrent_Type (Etype (Ent))
and then Etype (Ent) = Base_Type (Ent))
or else Ekind (Ent) = E_Package
or else Is_Generic_Unit (Ent)
then
Rewrite (N,
New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
-- Anything else is illegal
else
Error_Attr ("invalid prefix for % attribute", P);
end if;
end;
-- Object is OK
elsif Is_Object_Reference (P) then
return;
-- Subprogram called using dot notation
elsif Nkind (P) = N_Selected_Component
and then Is_Subprogram (Entity (Selector_Name (P)))
then
return;
-- What exactly are we allowing here ??? and is this properly
-- documented in the sinfo documentation for this node ???
elsif Relaxed_RM_Semantics
and then Nkind (P) = N_Attribute_Reference
then
return;
-- All other non-entity name cases are illegal
else
Error_Attr ("invalid prefix for % attribute", P);
end if;
end Address_Checks;
------------------------------
-- Analyze_Access_Attribute --
------------------------------
procedure Analyze_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 is the node itself. The
-- result is stored in Acc_Type.
function OK_Self_Reference return Boolean;
-- An access reference whose prefix is a type can legally appear
-- within an aggregate, where it is obtained by expansion of
-- a defaulted aggregate. The enclosing aggregate that contains
-- the self-referenced is flagged so that the self-reference can
-- be expanded into a reference to the target object (see exp_aggr).
------------------------------
-- Build_Access_Object_Type --
------------------------------
function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is
Typ : constant Entity_Id :=
New_Internal_Entity
(E_Access_Attribute_Type, Current_Scope, Loc, 'A');
begin
Set_Etype (Typ, 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;
procedure Check_Local_Access (E : Entity_Id);
-- Deal with possible access to local subprogram. If we have such
-- an access, we set a flag to kill all tracked values on any call
-- because this access value may be passed around, and any called
-- code might use it to access a local procedure which clobbers a
-- tracked value. If the scope is a loop or block, indicate that
-- value tracking is disabled for the enclosing subprogram.
function Get_Kind (E : Entity_Id) return Entity_Kind;
-- Distinguish between access to regular/protected subprograms
------------------------
-- Check_Local_Access --
------------------------
procedure Check_Local_Access (E : Entity_Id) is
begin
if not Is_Library_Level_Entity (E) then
Set_Suppress_Value_Tracking_On_Call (Current_Scope);
Set_Suppress_Value_Tracking_On_Call
(Nearest_Dynamic_Scope (Current_Scope));
end if;
end Check_Local_Access;
--------------
-- Get_Kind --
--------------
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
-- 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.
-- Note: This fragment of the tree is temporarily malformed
-- because the correct tree requires an E_Subprogram_Type entity
-- as the designated type. In most cases this designated type is
-- later overridden by the semantics with the type imposed by the
-- context during the resolution phase. In the specific case of
-- the expression Address!(Prim'Unrestricted_Access), used to
-- initialize slots of dispatch tables, this work will be done by
-- the expander (see Exp_Aggr).
-- The reason to temporarily add this kind of node to the tree
-- instead of a proper E_Subprogram_Type itype, is the following:
-- in case of errors found in the source file we report better
-- error messages. For example, instead of generating the
-- following error:
-- "expected access to subprogram with profile
-- defined at line X"
-- we currently generate:
-- "expected access to function Z defined at line X"
Set_Etype (N, Any_Type);
if not Is_Overloaded (P) then
Check_Local_Access (Entity (P));
if not Is_Intrinsic_Subprogram (Entity (P)) then
Acc_Type := Create_Itype (Get_Kind (Entity (P)), N);
Set_Is_Public (Acc_Type, False);
Set_Etype (Acc_Type, Acc_Type);
Set_Convention (Acc_Type, Convention (Entity (P)));
Set_Directly_Designated_Type (Acc_Type, Entity (P));
Set_Etype (N, Acc_Type);
Freeze_Before (N, Acc_Type);
end if;
else
Get_First_Interp (P, Index, It);
while Present (It.Nam) loop
Check_Local_Access (It.Nam);
if not Is_Intrinsic_Subprogram (It.Nam) then
Acc_Type := Create_Itype (Get_Kind (It.Nam), N);
Set_Is_Public (Acc_Type, False);
Set_Etype (Acc_Type, Acc_Type);
Set_Convention (Acc_Type, Convention (It.Nam));
Set_Directly_Designated_Type (Acc_Type, It.Nam);
Add_One_Interp (N, Acc_Type, Acc_Type);
Freeze_Before (N, Acc_Type);
end if;
Get_Next_Interp (Index, It);
end loop;
end if;
-- Cannot be applied to intrinsic. Looking at the tests above,
-- the only way Etype (N) can still be set to Any_Type is if
-- Is_Intrinsic_Subprogram was True for some referenced entity.
if Etype (N) = Any_Type then
Error_Attr_P ("prefix of % attribute cannot be intrinsic");
end if;
end Build_Access_Subprogram_Type;
----------------------
-- OK_Self_Reference --
----------------------
function OK_Self_Reference return Boolean is
Par : Node_Id;
begin
Par := Parent (N);
while Present (Par)
and then
(Nkind (Par) = N_Component_Association
or else Nkind (Par) in N_Subexpr)
loop
if Nkind_In (Par, N_Aggregate, N_Extension_Aggregate) then
if Etype (Par) = Typ then
Set_Has_Self_Reference (Par);
-- Check the context: the aggregate must be part of the
-- initialization of a type or component, or it is the
-- resulting expansion in an initialization procedure.
if Is_Init_Proc (Current_Scope) then
return True;
else
Par := Parent (Par);
while Present (Par) loop
if Nkind (Par) = N_Full_Type_Declaration then
return True;
end if;
Par := Parent (Par);
end loop;
end if;
return False;
end if;
end if;
Par := Parent (Par);
end loop;
-- No enclosing aggregate, or not a self-reference
return False;
end OK_Self_Reference;
-- Start of processing for Analyze_Access_Attribute
begin
Check_SPARK_05_Restriction_On_Attribute;
Check_E0;
if Nkind (P) = N_Character_Literal then
Error_Attr_P
("prefix of % attribute cannot be enumeration literal");
end if;
-- Case of access to subprogram
if Is_Entity_Name (P) and then Is_Overloadable (Entity (P)) then
if Has_Pragma_Inline_Always (Entity (P)) then
Error_Attr_P
("prefix of % attribute cannot be Inline_Always subprogram");
elsif Aname = Name_Unchecked_Access then
Error_Attr ("attribute% cannot be applied to a subprogram", P);
end if;
-- Issue an error if the prefix denotes an eliminated subprogram
Check_For_Eliminated_Subprogram (P, Entity (P));
-- Check for obsolescent subprogram reference
Check_Obsolescent_2005_Entity (Entity (P), P);
-- Build the appropriate subprogram type
Build_Access_Subprogram_Type (P);
-- For P'Access or P'Unrestricted_Access, where P is a nested
-- subprogram, we might be passing P to another subprogram (but we
-- don't check that here), which might call P. P could modify
-- local variables, so we need to kill current values. It is
-- important not to do this for library-level subprograms, because
-- Kill_Current_Values is very inefficient in the case of library
-- level packages with lots of tagged types.
if Is_Library_Level_Entity (Entity (Prefix (N))) then
null;
-- Do not kill values on nodes initializing dispatch tables
-- slots. The construct Prim_Ptr!(Prim'Unrestricted_Access)
-- is currently generated by the expander only for this
-- purpose. Done to keep the quality of warnings currently
-- generated by the compiler (otherwise any declaration of
-- a tagged type cleans constant indications from its scope).
elsif Nkind (Parent (N)) = N_Unchecked_Type_Conversion
and then (Etype (Parent (N)) = RTE (RE_Prim_Ptr)
or else
Etype (Parent (N)) = RTE (RE_Size_Ptr))
and then Is_Dispatching_Operation
(Directly_Designated_Type (Etype (N)))
then
null;
else
Kill_Current_Values;
end if;
-- In the static elaboration model, treat the attribute reference
-- as a call for elaboration purposes. Suppress this treatment
-- under debug flag. In any case, we are all done.
if not Dynamic_Elaboration_Checks and not Debug_Flag_Dot_UU then
Check_Elab_Call (N);
end if;
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_P ("prefix of % attribute must be subprogram");
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,
-- or in Ada 2005 self-referential pointer in a default-initialized
-- aggregate.
if Is_Entity_Name (P) then
Typ := Entity (P);
-- The reference may appear in an aggregate that has been expanded
-- into a loop. Locate scope of type definition, if any.
Scop := Current_Scope;
while Ekind (Scop) = E_Loop loop
Scop := Scope (Scop);
end loop;
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_F
("current instance prefix must be a direct name", P);
end if;
-- If a current instance attribute appears in a component
-- constraint it must appear alone; other contexts (spec-
-- expressions, within a task body) are not subject to this
-- restriction.
if not In_Spec_Expression
and then not Has_Completion (Scop)
and then not
Nkind_In (Parent (N), N_Discriminant_Association,
N_Index_Or_Discriminant_Constraint)
then
Error_Msg_N
("current instance attribute must appear alone", N);
end if;
if Is_CPP_Class (Root_Type (Typ)) then
Error_Msg_N
("??current instance unsupported for derivations of "
& "'C'P'P types", 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 Is_Init_Proc (Scop)
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;
-- OK if self-reference in an aggregate in Ada 2005, and
-- the reference comes from a copied default expression.
-- Note that we check legality of self-reference even if the
-- expression comes from source, e.g. when a single component
-- association in an aggregate has a box association.
elsif Ada_Version >= Ada_2005
and then OK_Self_Reference
then
null;
-- OK if reference to current instance of a protected object
elsif Is_Protected_Self_Reference (P) 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 (for now) 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;
-- Special cases when we can find a prefix that is an entity name
declare
PP : Node_Id;
Ent : Entity_Id;
begin
PP := P;
loop
if Is_Entity_Name (PP) then
Ent := Entity (PP);
-- If we have an access to an object, and the attribute
-- comes from source, then set the object as potentially
-- source modified. We do this because the resulting access
-- pointer can be used to modify the variable, and we might
-- not detect this, leading to some junk warnings.
-- We only do this for source references, since otherwise
-- we can suppress warnings, e.g. from the unrestricted
-- access generated for validity checks in -gnatVa mode.
if Comes_From_Source (N) then
Set_Never_Set_In_Source (Ent, False);
end if;
-- Mark entity as address taken in the case of
-- 'Unrestricted_Access or subprograms, and kill current
-- values.
if Aname = Name_Unrestricted_Access
or else Is_Subprogram (Ent)
then
Set_Address_Taken (Ent);
end if;
Kill_Current_Values (Ent);
exit;
elsif Nkind_In (PP, N_Selected_Component,
N_Indexed_Component)
then
PP := Prefix (PP);
else
exit;
end if;
end loop;
end;
-- Check for aliased view. 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). Similarly, within an inlined body we know that the
-- attribute is legal in the original subprogram, and therefore
-- legal in the expansion.
if not Is_Aliased_View (P)
and then not In_Instance
and then not In_Inlined_Body
and then Comes_From_Source (N)
then
-- Here we have a non-aliased view. This is illegal unless we
-- have the case of Unrestricted_Access, where for now we allow
-- this (we will reject later if expected type is access to an
-- unconstrained array with a thin pointer).
-- No need for an error message on a generated access reference
-- for the controlling argument in a dispatching call: error will
-- be reported when resolving the call.
if Aname /= Name_Unrestricted_Access then
Error_Attr_P ("prefix of % attribute must be aliased");
Check_No_Implicit_Aliasing (P);
-- For Unrestricted_Access, record that prefix is not aliased
-- to simplify legality check later on.
else
Set_Non_Aliased_Prefix (N);
end if;
-- If we have an aliased view, and we have Unrestricted_Access, then
-- output a warning that Unchecked_Access would have been fine, and
-- change the node to be Unchecked_Access.
else
-- For now, hold off on this change ???
null;
end if;
end Analyze_Access_Attribute;
----------------------------------
-- Analyze_Attribute_Old_Result --
----------------------------------
procedure Analyze_Attribute_Old_Result
(Legal : out Boolean;
Spec_Id : out Entity_Id)
is
procedure Check_Placement_In_Check (Prag : Node_Id);
-- Verify that the attribute appears within pragma Check that mimics
-- a postcondition.
procedure Check_Placement_In_Contract_Cases (Prag : Node_Id);
-- Verify that the attribute appears within a consequence of aspect
-- or pragma Contract_Cases denoted by Prag.
procedure Check_Placement_In_Test_Case (Prag : Node_Id);
-- Verify that the attribute appears within the "Ensures" argument of
-- aspect or pragma Test_Case denoted by Prag.
function Is_Within
(Nod : Node_Id;
Encl_Nod : Node_Id) return Boolean;
-- Subsidiary to Check_Placemenet_In_XXX. Determine whether arbitrary
-- node Nod is within enclosing node Encl_Nod.
procedure Placement_Error;
-- Emit a general error when the attributes does not appear in a
-- postcondition-like aspect or pragma.
------------------------------
-- Check_Placement_In_Check --
------------------------------
procedure Check_Placement_In_Check (Prag : Node_Id) is
Args : constant List_Id := Pragma_Argument_Associations (Prag);
Nam : constant Name_Id := Chars (Get_Pragma_Arg (First (Args)));
begin
-- The "Name" argument of pragma Check denotes a postcondition
if Nam_In (Nam, Name_Post,
Name_Post_Class,
Name_Postcondition,
Name_Refined_Post)
then
null;
-- Otherwise the placement of the attribute is illegal
else
Placement_Error;
end if;
end Check_Placement_In_Check;
---------------------------------------
-- Check_Placement_In_Contract_Cases --
---------------------------------------
procedure Check_Placement_In_Contract_Cases (Prag : Node_Id) is
Arg : Node_Id;
Cases : Node_Id;
CCase : Node_Id;
begin
-- Obtain the argument of the aspect or pragma
if Nkind (Prag) = N_Aspect_Specification then
Arg := Prag;
else
Arg := First (Pragma_Argument_Associations (Prag));
end if;
Cases := Expression (Arg);
if Present (Component_Associations (Cases)) then
CCase := First (Component_Associations (Cases));
while Present (CCase) loop
-- Detect whether the attribute appears within the
-- consequence of the current contract case.
if Nkind (CCase) = N_Component_Association
and then Is_Within (N, Expression (CCase))
then
return;
end if;
Next (CCase);
end loop;
end if;
-- Otherwise aspect or pragma Contract_Cases is either malformed
-- or the attribute does not appear within a consequence.
Error_Attr
("attribute % must appear in the consequence of a contract case",
P);
end Check_Placement_In_Contract_Cases;
----------------------------------
-- Check_Placement_In_Test_Case --
----------------------------------
procedure Check_Placement_In_Test_Case (Prag : Node_Id) is
Arg : constant Node_Id :=
Test_Case_Arg
(Prag => Prag,
Arg_Nam => Name_Ensures,
From_Aspect => Nkind (Prag) = N_Aspect_Specification);
begin
-- Detect whether the attribute appears within the "Ensures"
-- expression of aspect or pragma Test_Case.
if Present (Arg) and then Is_Within (N, Arg) then
null;
else
Error_Attr
("attribute % must appear in the ensures expression of a "
& "test case", P);
end if;
end Check_Placement_In_Test_Case;
---------------
-- Is_Within --
---------------
function Is_Within
(Nod : Node_Id;
Encl_Nod : Node_Id) return Boolean
is
Par : Node_Id;
begin
Par := Nod;
while Present (Par) loop
if Par = Encl_Nod then
return True;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Par) then
exit;
end if;
Par := Parent (Par);
end loop;
return False;
end Is_Within;
---------------------
-- Placement_Error --
---------------------
procedure Placement_Error is
begin
if Aname = Name_Old then
Error_Attr ("attribute % can only appear in postcondition", P);
-- Specialize the error message for attribute 'Result
else
Error_Attr
("attribute % can only appear in postcondition of function",
P);
end if;
end Placement_Error;
-- Local variables
Prag : Node_Id;
Prag_Nam : Name_Id;
Subp_Decl : Node_Id;
-- Start of processing for Analyze_Attribute_Old_Result
begin
-- Assume that the attribute is illegal
Legal := False;
Spec_Id := Empty;
-- Traverse the parent chain to find the aspect or pragma where the
-- attribute resides.
Prag := N;
while Present (Prag) loop
if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then
exit;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Prag) then
exit;
end if;
Prag := Parent (Prag);
end loop;
-- The attribute is allowed to appear only in postcondition-like
-- aspects or pragmas.
if Nkind_In (Prag, N_Aspect_Specification, N_Pragma) then
if Nkind (Prag) = N_Aspect_Specification then
Prag_Nam := Chars (Identifier (Prag));
else
Prag_Nam := Pragma_Name (Prag);
end if;
if Prag_Nam = Name_Check then
Check_Placement_In_Check (Prag);
elsif Prag_Nam = Name_Contract_Cases then
Check_Placement_In_Contract_Cases (Prag);
-- Attribute 'Result is allowed to appear in aspect or pragma
-- [Refined_]Depends (SPARK RM 6.1.5(11)).
elsif Nam_In (Prag_Nam, Name_Depends, Name_Refined_Depends)
and then Aname = Name_Result
then
null;
elsif Nam_In (Prag_Nam, Name_Post,
Name_Post_Class,
Name_Postcondition,
Name_Refined_Post)
then
null;
elsif Prag_Nam = Name_Test_Case then
Check_Placement_In_Test_Case (Prag);
else
Placement_Error;
return;
end if;
-- Otherwise the placement of the attribute is illegal
else
Placement_Error;
return;
end if;
-- Find the related subprogram subject to the aspect or pragma
if Nkind (Prag) = N_Aspect_Specification then
Subp_Decl := Parent (Prag);
else
Subp_Decl := Find_Related_Declaration_Or_Body (Prag);
end if;
-- The aspect or pragma where the attribute resides should be
-- associated with a subprogram declaration or a body. If this is not
-- the case, then the aspect or pragma is illegal. Return as analysis
-- cannot be carried out. Note that it is legal to have the aspect
-- appear on a subprogram renaming, when the renamed entity is an
-- attribute reference.
-- Generating C code the internally built nested _postcondition
-- subprograms are inlined; after expanded, inlined aspects are
-- located in the internal block generated by the frontend.
if Nkind (Subp_Decl) = N_Block_Statement
and then Modify_Tree_For_C
and then In_Inlined_Body
then
null;
elsif not Nkind_In (Subp_Decl, N_Abstract_Subprogram_Declaration,
N_Entry_Declaration,
N_Generic_Subprogram_Declaration,
N_Subprogram_Body,
N_Subprogram_Body_Stub,
N_Subprogram_Declaration,
N_Subprogram_Renaming_Declaration)
then
return;
end if;
-- If we get here, then the attribute is legal
Legal := True;
Spec_Id := Unique_Defining_Entity (Subp_Decl);
-- When generating C code, nested _postcondition subprograms are
-- inlined by the front end to avoid problems (when unnested) with
-- referenced itypes. Handle that here, since as part of inlining the
-- expander nests subprogram within a dummy procedure named _parent
-- (see Build_Postconditions_Procedure and Build_Body_To_Inline).
-- Hence, in this context, the spec_id of _postconditions is the
-- enclosing scope.
if Modify_Tree_For_C
and then Chars (Spec_Id) = Name_uParent
and then Chars (Scope (Spec_Id)) = Name_uPostconditions
then
-- This situation occurs only when preanalyzing the inlined body
pragma Assert (not Full_Analysis);
Spec_Id := Scope (Spec_Id);
pragma Assert (Is_Inlined (Spec_Id));
end if;
end Analyze_Attribute_Old_Result;
---------------------------------
-- Bad_Attribute_For_Predicate --
---------------------------------
procedure Bad_Attribute_For_Predicate is
begin
if Is_Scalar_Type (P_Type)
and then Comes_From_Source (N)
then
Error_Msg_Name_1 := Aname;
Bad_Predicated_Subtype_Use
("type& has predicates, attribute % not allowed", N, P_Type);
end if;
end Bad_Attribute_For_Predicate;
--------------------------------
-- Check_Array_Or_Scalar_Type --
--------------------------------
procedure Check_Array_Or_Scalar_Type is
function In_Aspect_Specification return Boolean;
-- A current instance of a type in an aspect specification is an
-- object and not a type, and therefore cannot be of a scalar type
-- in the prefix of one of the array attributes if the attribute
-- reference is part of an aspect expression.
-----------------------------
-- In_Aspect_Specification --
-----------------------------
function In_Aspect_Specification return Boolean is
P : Node_Id;
begin
P := Parent (N);
while Present (P) loop
if Nkind (P) = N_Aspect_Specification then
return P_Type = Entity (P);
elsif Nkind (P) in N_Declaration then
return False;
end if;
P := Parent (P);
end loop;
return False;
end In_Aspect_Specification;
-- Local variables
Dims : Int;
Index : Entity_Id;
-- Start of processing for Check_Array_Or_Scalar_Type
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);
elsif In_Aspect_Specification then
Error_Attr
("prefix of % attribute cannot be the current instance of a "
& "scalar type", P);
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.
pragma Assert (Is_Array_Type (P_Type));
Index := First_Index (P_Base_Type);
if No (E1) then
-- First dimension assumed
Set_Etype (N, Base_Type (Etype (Index)));
else
Dims := UI_To_Int (Intval (E1));
for J in 1 .. Dims - 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;
Check_Dereference;
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_F
("prefix for % attribute must be constrained array", P);
end if;
-- The attribute reference freezes the type, and thus the
-- component type, even if the attribute may not depend on the
-- component. Diagnose arrays with incomplete components now.
-- If the prefix is an access to array, this does not freeze
-- the designated type.
if Nkind (P) /= N_Explicit_Dereference then
Check_Fully_Declared (Component_Type (P_Type), P);
end if;
D := Number_Dimensions (P_Type);
else
if Is_Private_Type (P_Type) then
Error_Attr_P ("prefix for % attribute may not be private type");
elsif Is_Access_Type (P_Type)
and then Is_Array_Type (Designated_Type (P_Type))
and then Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
Error_Attr_P ("prefix of % attribute cannot be access type");
elsif Attr_Id = Attribute_First
or else
Attr_Id = Attribute_Last
then
Error_Attr ("invalid prefix for % attribute", P);
else
Error_Attr_P ("prefix for % attribute must be array");
end if;
end if;
if Present (E1) then
Resolve (E1, Any_Integer);
Set_Etype (E1, Standard_Integer);
if not Is_OK_Static_Expression (E1)
or else Raises_Constraint_Error (E1)
then
Flag_Non_Static_Expr
("expression for dimension must be static!", E1);
Error_Attr;
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;
if (Style_Check and Style_Check_Array_Attribute_Index)
and then Comes_From_Source (N)
then
Style.Check_Array_Attribute_Index (N, E1, D);
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
Flag_Non_Static_Expr
("constraint argument must be static string expression!", E1);
Error_Attr;
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_P ("prefix for % attribute must be selected component");
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_P ("prefix of % attribute must be decimal type");
end if;
end Check_Decimal_Fixed_Point_Type;
-----------------------
-- Check_Dereference --
-----------------------
procedure Check_Dereference is
begin
-- Case of a subtype mark
if Is_Entity_Name (P) and then Is_Type (Entity (P)) then
return;
end if;
-- Case of an expression
Resolve (P);
if Is_Access_Type (P_Type) then
-- 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).
-- As done elsewhere, freezing must not happen when pre-analyzing
-- a pre- or postcondition or a default value for an object or for
-- a formal parameter.
if not In_Spec_Expression then
Freeze_Before (N, Designated_Type (P_Type));
end if;
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);
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_P ("prefix of % attribute must be discrete type");
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 Nam_In (Attribute_Name (Parent (N)), Name_Address,
Name_Code_Address,
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
-- When an enumeration type appears in an attribute reference, all
-- literals of the type are marked as referenced. This must only be
-- done if the attribute reference appears in the current source.
-- Otherwise the information on references may differ between a
-- normal compilation and one that performs inlining.
if Is_Enumeration_Type (P_Base_Type)
and then In_Extended_Main_Code_Unit (N)
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_First_Last_Valid --
----------------------------
procedure Check_First_Last_Valid is
begin
Check_Discrete_Type;
-- Freeze the subtype now, so that the following test for predicates
-- works (we set the predicates stuff up at freeze time)
Insert_Actions (N, Freeze_Entity (P_Type, P));
-- Now test for dynamic predicate
if Has_Predicates (P_Type)
and then not (Has_Static_Predicate (P_Type))
then
Error_Attr_P
("prefix of % attribute may not have dynamic predicate");
end if;
-- Check non-static subtype
if not Is_OK_Static_Subtype (P_Type) then
Error_Attr_P ("prefix of % attribute must be a static subtype");
end if;
-- Test case for no values
if Expr_Value (Type_Low_Bound (P_Type)) >
Expr_Value (Type_High_Bound (P_Type))
or else (Has_Predicates (P_Type)
and then
Is_Empty_List (Static_Discrete_Predicate (P_Type)))
then
Error_Attr_P
("prefix of % attribute must be subtype with at least one "
& "value");
end if;
end Check_First_Last_Valid;
----------------------------
-- Check_Fixed_Point_Type --
----------------------------
procedure Check_Fixed_Point_Type is
begin
Check_Type;
if not Is_Fixed_Point_Type (P_Type) then
Error_Attr_P ("prefix of % attribute must be fixed point type");
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_P ("prefix of % attribute must be float type");
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_P ("prefix of % attribute must be integer type");
end if;
end Check_Integer_Type;
--------------------------------
-- Check_Modular_Integer_Type --
--------------------------------
procedure Check_Modular_Integer_Type is
begin
Check_Type;
if not Is_Modular_Integer_Type (P_Type) then
Error_Attr_P
("prefix of % attribute must be modular integer type");
end if;
end Check_Modular_Integer_Type;
------------------------
-- Check_Not_CPP_Type --
------------------------
procedure Check_Not_CPP_Type is
begin
if Is_Tagged_Type (Etype (P))
and then Convention (Etype (P)) = Convention_CPP
and then Is_CPP_Class (Root_Type (Etype (P)))
then
Error_Attr_P
("invalid use of % attribute with 'C'P'P tagged type");
end if;
end Check_Not_CPP_Type;
-------------------------------
-- Check_Not_Incomplete_Type --
-------------------------------
procedure Check_Not_Incomplete_Type is
E : Entity_Id;
Typ : Entity_Id;
begin
-- Ada 2005 (AI-50217, AI-326): If the prefix is an explicit
-- dereference we have to check wrong uses of incomplete types
-- (other wrong uses are checked at their freezing point).
-- In Ada 2012, incomplete types can appear in subprogram
-- profiles, but formals with incomplete types cannot be the
-- prefix of attributes.
-- Example 1: Limited-with
-- limited with Pkg;
-- package P is
-- type Acc is access Pkg.T;
-- X : Acc;
-- S : Integer := X.all'Size; -- ERROR
-- end P;
-- Example 2: Tagged incomplete
-- type T is tagged;
-- type Acc is access all T;
-- X : Acc;
-- S : constant Integer := X.all'Size; -- ERROR
-- procedure Q (Obj : Integer := X.all'Alignment); -- ERROR
if Ada_Version >= Ada_2005
and then Nkind (P) = N_Explicit_Dereference
then
E := P;
while Nkind (E) = N_Explicit_Dereference loop
E := Prefix (E);
end loop;
Typ := Etype (E);
if From_Limited_With (Typ) then
Error_Attr_P
("prefix of % attribute cannot be an incomplete type");
-- If the prefix is an access type check the designated type
elsif Is_Access_Type (Typ)
and then Nkind (P) = N_Explicit_Dereference
then
Typ := Directly_Designated_Type (Typ);
end if;
if Is_Class_Wide_Type (Typ) then
Typ := Root_Type (Typ);
end if;
-- A legal use of a shadow entity occurs only when the unit where
-- the non-limited view resides is imported via a regular with
-- clause in the current body. Such references to shadow entities
-- may occur in subprogram formals.
if Is_Incomplete_Type (Typ)
and then From_Limited_With (Typ)
and then Present (Non_Limited_View (Typ))
and then Is_Legal_Shadow_Entity_In_Body (Typ)
then
Typ := Non_Limited_View (Typ);
end if;
-- If still incomplete, it can be a local incomplete type, or a
-- limited view whose scope is also a limited view.
if Ekind (Typ) = E_Incomplete_Type then
if not From_Limited_With (Typ)
and then No (Full_View (Typ))
then
Error_Attr_P
("prefix of % attribute cannot be an incomplete type");
-- The limited view may be available indirectly through
-- an intermediate unit. If the non-limited view is available
-- the attribute reference is legal.
elsif From_Limited_With (Typ)
and then
(No (Non_Limited_View (Typ))
or else Is_Incomplete_Type (Non_Limited_View (Typ)))
then
Error_Attr_P
("prefix of % attribute cannot be an incomplete type");
end if;
end if;
-- Ada 2012 : formals in bodies may be incomplete, but no attribute
-- legally applies.
elsif Is_Entity_Name (P)
and then Is_Formal (Entity (P))
and then Is_Incomplete_Type (Etype (Etype (P)))
then
Error_Attr_P
("prefix of % attribute cannot be an incomplete type");
end if;
if not Is_Entity_Name (P)
or else not Is_Type (Entity (P))
or else In_Spec_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_P ("prefix of % attribute must be object");
end if;
end Check_Object_Reference;
----------------------------
-- Check_PolyORB_Attribute --
----------------------------
procedure Check_PolyORB_Attribute is
begin
Validate_Non_Static_Attribute_Function_Call;
Check_Type;
Check_Not_CPP_Type;
if Get_PCS_Name /= Name_PolyORB_DSA then
Error_Attr
("attribute% requires the 'Poly'O'R'B 'P'C'S", N);
end if;
end Check_PolyORB_Attribute;
------------------------
-- 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_P ("prefix of % attribute must be program unit");
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_P ("prefix of % attribute must be real type");
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_P ("prefix of % attribute must be scalar type");
end if;
end Check_Scalar_Type;
------------------------------------------
-- Check_SPARK_05_Restriction_On_Attribute --
------------------------------------------
procedure Check_SPARK_05_Restriction_On_Attribute is
begin
Error_Msg_Name_1 := Aname;
Check_SPARK_05_Restriction ("attribute % is not allowed", P);
end Check_SPARK_05_Restriction_On_Attribute;
---------------------------
-- 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 : TSS_Name_Type) is
Etyp : Entity_Id;
Btyp : Entity_Id;
In_Shared_Var_Procs : Boolean;
-- True when compiling System.Shared_Storage.Shared_Var_Procs body.
-- For this runtime package (always compiled in GNAT mode), we allow
-- stream attributes references for limited types for the case where
-- shared passive objects are implemented using stream attributes,
-- which is the default in GNAT's persistent storage implementation.
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 = TSS_Stream_Input then
null;
elsif Is_List_Member (N)
and then not Nkind_In (Parent (N), N_Procedure_Call_Statement,
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
-- attribute reference was generated by the expander (in which
-- case the underlying type will be used, as described in Sinfo),
-- or the attribute was specified explicitly for the type itself
-- or one of its ancestors (taking visibility rules into account if
-- in Ada 2005 mode), or a pragma Stream_Convert applies to Btyp
-- (with no visibility restriction).
declare
Gen_Body : constant Node_Id := Enclosing_Generic_Body (N);
begin
if Present (Gen_Body) then
In_Shared_Var_Procs :=
Is_RTE (Corresponding_Spec (Gen_Body), RE_Shared_Var_Procs);
else
In_Shared_Var_Procs := False;
end if;
end;
if (Comes_From_Source (N)
and then not (In_Shared_Var_Procs or In_Instance))
and then not Stream_Attribute_Available (P_Type, Nam)
and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert)
then
Error_Msg_Name_1 := Aname;
if Is_Limited_Type (P_Type) then
Error_Msg_NE
("limited type& has no% attribute", P, P_Type);
Explain_Limited_Type (P_Type, P);
else
Error_Msg_NE
("attribute% for type& is not available", P, P_Type);
end if;
end if;
-- Check for no stream operations allowed from No_Tagged_Streams
if Is_Tagged_Type (P_Type)
and then Present (No_Tagged_Streams_Pragma (P_Type))
then
Error_Msg_Sloc := Sloc (No_Tagged_Streams_Pragma (P_Type));
Error_Msg_NE
("no stream operations for & (No_Tagged_Streams #)", N, P_Type);
return;
end if;
-- Check restriction violations
-- First check the No_Streams restriction, which prohibits the use
-- of explicit stream attributes in the source program. We do not
-- prevent the occurrence of stream attributes in generated code,
-- for instance those generated implicitly for dispatching purposes.
if Comes_From_Source (N) then
Check_Restriction (No_Streams, P);
end if;
-- AI05-0057: if restriction No_Default_Stream_Attributes is active,
-- it is illegal to use a predefined elementary type stream attribute
-- either by itself, or more importantly as part of the attribute
-- subprogram for a composite type. However, if the broader
-- restriction No_Streams is active, stream operations are not
-- generated, and there is no error.
if Restriction_Active (No_Default_Stream_Attributes)
and then not Restriction_Active (No_Streams)
then
declare
T : Entity_Id;
begin
if Nam = TSS_Stream_Input
or else
Nam = TSS_Stream_Read
then
T :=
Type_Without_Stream_Operation (P_Type, TSS_Stream_Read);
else
T :=
Type_Without_Stream_Operation (P_Type, TSS_Stream_Write);
end if;
if Present (T) then
Check_Restriction (No_Default_Stream_Attributes, N);
Error_Msg_NE
("missing user-defined Stream Read or Write for type&",
N, T);
if not Is_Elementary_Type (P_Type) then
Error_Msg_NE
("\which is a component of type&", N, P_Type);
end if;
end if;
end;
end if;
-- Check special case of Exception_Id and Exception_Occurrence which
-- are not allowed for restriction No_Exception_Registration.
if Restriction_Check_Required (No_Exception_Registration)
and then (Is_RTE (P_Type, RE_Exception_Id)
or else
Is_RTE (P_Type, RE_Exception_Occurrence))
then
Check_Restriction (No_Exception_Registration, P);
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 = TSS_Stream_Read
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;
Check_Not_CPP_Type;
end Check_Stream_Attribute;
-------------------------
-- Check_System_Prefix --
-------------------------
procedure Check_System_Prefix is
begin
if Nkind (P) /= N_Identifier or else Chars (P) /= Name_System then
Error_Attr ("only allowed prefix for % attribute is System", P);
end if;
end Check_System_Prefix;
-----------------------
-- Check_Task_Prefix --
-----------------------
procedure Check_Task_Prefix is
begin
Analyze (P);
-- Ada 2005 (AI-345): Attribute 'Terminated can be applied to
-- task interface class-wide types.
if Is_Task_Type (Etype (P))
or else (Is_Access_Type (Etype (P))
and then Is_Task_Type (Designated_Type (Etype (P))))
or else (Ada_Version >= Ada_2005
and then Ekind (Etype (P)) = E_Class_Wide_Type
and then Is_Interface (Etype (P))
and then Is_Task_Interface (Etype (P)))
then
Resolve (P);
else
if Ada_Version >= Ada_2005 then
Error_Attr_P
("prefix of % attribute must be a task or a task " &
"interface class-wide object");
else
Error_Attr_P ("prefix of % attribute must be a task");
end if;
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_P ("prefix of % attribute must be a type");
elsif Is_Protected_Self_Reference (P) then
Error_Attr_P
("prefix of % attribute denotes current instance "
& "(RM 9.4(21/2))");
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_In (Nod, N_Selected_Component, N_Expanded_Name) 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 is
begin
Set_Etype (N, Any_Type);
Set_Entity (N, Any_Type);
raise Bad_Attribute;
end Error_Attr;
procedure Error_Attr (Msg : String; Error_Node : Node_Id) is
begin
Error_Msg_Name_1 := Aname;
Error_Msg_N (Msg, Error_Node);
Error_Attr;
end Error_Attr;
------------------
-- Error_Attr_P --
------------------
procedure Error_Attr_P (Msg : String) is
begin
Error_Msg_Name_1 := Aname;
Error_Msg_F (Msg, P);
Error_Attr;
end Error_Attr_P;
----------------------------
-- 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_P ("prefix of % attribute must be generic type");
elsif Is_Generic_Actual_Type (Entity (P))
or else In_Instance
or else In_Inlined_Body
then
null;
elsif Is_Generic_Type (Entity (P)) then
if Is_Definite_Subtype (Entity (P)) then
Error_Attr_P
("prefix of % attribute must be indefinite generic type");
end if;
else
Error_Attr_P
("prefix of % attribute must be indefinite generic type");
end if;
Set_Etype (N, Standard_Boolean);
end Legal_Formal_Attribute;
---------------------------------------------------------------
-- Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements --
---------------------------------------------------------------
procedure Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements is
begin
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Universal_Integer);
end Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
-------------
-- Min_Max --
-------------
procedure Min_Max is
begin
Check_E2;
Check_Scalar_Type;
Resolve (E1, P_Base_Type);
Resolve (E2, P_Base_Type);
Set_Etype (N, P_Base_Type);
-- Check for comparison on unordered enumeration type
if Bad_Unordered_Enumeration_Reference (N, P_Base_Type) then
Error_Msg_Sloc := Sloc (P_Base_Type);
Error_Msg_NE
("comparison on unordered enumeration type& declared#?U?",
N, P_Base_Type);
end if;
end Min_Max;
------------------------
-- Standard_Attribute --
------------------------
procedure Standard_Attribute (Val : Int) is
begin
Check_Standard_Prefix;
Rewrite (N, Make_Integer_Literal (Loc, Val));
Analyze (N);
Set_Is_Static_Expression (N, True);
end Standard_Attribute;
--------------------
-- Uneval_Old_Msg --
--------------------
procedure Uneval_Old_Msg is
Uneval_Old_Setting : Character;
Prag : Node_Id;
begin
-- If from aspect, then Uneval_Old_Setting comes from flags in the
-- N_Aspect_Specification node that corresponds to the attribute.
-- First find the pragma in which we appear (note that at this stage,
-- even if we appeared originally within an aspect specification, we
-- are now within the corresponding pragma).
Prag := N;
loop
Prag := Parent (Prag);
exit when No (Prag) or else Nkind (Prag) = N_Pragma;
end loop;
if Present (Prag) then
if Uneval_Old_Accept (Prag) then
Uneval_Old_Setting := 'A';
elsif Uneval_Old_Warn (Prag) then
Uneval_Old_Setting := 'W';
else
Uneval_Old_Setting := 'E';
end if;
-- If we did not find the pragma, that's odd, just use the setting
-- from Opt.Uneval_Old. Perhaps this is due to a previous error?
else
Uneval_Old_Setting := Opt.Uneval_Old;
end if;
-- Processing depends on the setting of Uneval_Old
case Uneval_Old_Setting is
when 'E' =>
Error_Attr_P
("prefix of attribute % that is potentially "
& "unevaluated must denote an entity");
when 'W' =>
Error_Msg_Name_1 := Aname;
Error_Msg_F
("??prefix of attribute % appears in potentially "
& "unevaluated context, exception may be raised", P);
when 'A' =>
null;
when others =>
raise Program_Error;
end case;
end Uneval_Old_Msg;
-------------------------
-- 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
Flag_Non_Static_Expr
("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;
Check_Restriction_No_Use_Of_Attribute (N);
-- Deal with Ada 83 issues
if Comes_From_Source (N) then
if not Attribute_83 (Attr_Id) then
if Ada_Version = 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;
end if;
-- Deal with Ada 2005 attributes that are implementation attributes
-- because they appear in a version of Ada before Ada 2005, and
-- similarly for Ada 2012 attributes appearing in an earlier version.
if (Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005)
or else
(Attribute_12 (Attr_Id) and then Ada_Version < Ada_2012)
then
Check_Restriction (No_Implementation_Attributes, N);
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
Discard_Node (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. Note that there are
-- some attributes for which we do not analyze the prefix, since the
-- prefix is not a normal name, or else needs special handling.
if Aname /= Name_Elab_Body and then
Aname /= Name_Elab_Spec and then
Aname /= Name_Elab_Subp_Body and then
Aname /= Name_Enabled and then
Aname /= Name_Old
then
Analyze (P);
P_Type := Etype (P);
if Is_Entity_Name (P)
and then Present (Entity (P))
and then Is_Type (Entity (P))
then
if Ekind (Entity (P)) = E_Incomplete_Type then
P_Type := Get_Full_View (P_Type);
Set_Entity (P, P_Type);
Set_Etype (P, P_Type);
elsif Entity (P) = Current_Scope
and then Is_Record_Type (Entity (P))
then
-- Use of current instance within the type. Verify that if the
-- attribute appears within a constraint, it yields an access
-- type, other uses are illegal.
declare
Par : Node_Id;
begin
Par := Parent (N);
while Present (Par)
and then Nkind (Parent (Par)) /= N_Component_Definition
loop
Par := Parent (Par);
end loop;
if Present (Par)
and then Nkind (Par) = N_Subtype_Indication
then
if Attr_Id /= Attribute_Access
and then Attr_Id /= Attribute_Unchecked_Access
and then Attr_Id /= Attribute_Unrestricted_Access
then
Error_Msg_N
("in a constraint the current instance can only "
& "be used with an access attribute", N);
end if;
end if;
end;
end if;
end if;
if P_Type = Any_Type then
raise Bad_Attribute;
end if;
P_Base_Type := Base_Type (P_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);
-- Skip analysis for case of Restriction_Set, we do not expect
-- the argument to be analyzed in this case.
if Aname /= Name_Restriction_Set then
Analyze (E1);
-- Check for missing/bad expression (result of previous error)
if No (E1) or else Etype (E1) = Any_Type then
raise Bad_Attribute;
end if;
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;
-- Cases where prefix must be resolvable by itself
if Is_Overloaded (P)
and then Aname /= Name_Access
and then Aname /= Name_Address
and then Aname /= Name_Code_Address
and then Aname /= Name_Result
and then Aname /= Name_Unchecked_Access
then
-- The prefix must be resolvable by itself, without reference to the
-- attribute. One case that requires special handling is a prefix
-- that is a function name, where one interpretation may be a
-- parameterless call. Entry attributes are handled specially below.
if Is_Entity_Name (P)
and then not Nam_In (Aname, Name_Count, Name_Caller)
then
Check_Parameterless_Call (P);
end if;
if Is_Overloaded (P) then
-- Ada 2005 (AI-345): Since protected and task types have
-- primitive entry wrappers, the attributes Count, and Caller
-- require a context check
if Nam_In (Aname, Name_Count, Name_Caller) then
declare
Count : Natural := 0;
I : Interp_Index;
It : Interp;
begin
Get_First_Interp (P, I, It);
while Present (It.Nam) loop
if Comes_From_Source (It.Nam) then
Count := Count + 1;
else
Remove_Interp (I);
end if;
Get_Next_Interp (I, It);
end loop;
if Count > 1 then
Error_Attr ("ambiguous prefix for % attribute", P);
else
Set_Is_Overloaded (P, False);
end if;
end;
else
Error_Attr ("ambiguous prefix for % attribute", P);
end if;
end if;
end if;
-- In SPARK, attributes of private types are only allowed if the full
-- type declaration is visible.
-- Note: the check for Present (Entity (P)) defends against some error
-- conditions where the Entity field is not set.
if Is_Entity_Name (P) and then Present (Entity (P))
and then Is_Type (Entity (P))
and then Is_Private_Type (P_Type)
and then not In_Open_Scopes (Scope (P_Type))
and then not In_Spec_Expression
then
Check_SPARK_05_Restriction ("invisible attribute of type", N);
end if;
-- Remaining processing depends on attribute
case Attr_Id is
-- Attributes related to Ada 2012 iterators. Attribute specifications
-- exist for these, but they cannot be queried.
when Attribute_Constant_Indexing
| Attribute_Default_Iterator
| Attribute_Implicit_Dereference
| Attribute_Iterator_Element
| Attribute_Iterable
| Attribute_Variable_Indexing
=>
Error_Msg_N ("illegal attribute", N);
-- Internal attributes used to deal with Ada 2012 delayed aspects. These
-- were already rejected by the parser. Thus they shouldn't appear here.
when Internal_Attribute_Id =>
raise Program_Error;
------------------
-- Abort_Signal --
------------------
when Attribute_Abort_Signal =>
Check_Standard_Prefix;
Rewrite (N, New_Occurrence_Of (Stand.Abort_Signal, Loc));
Analyze (N);
------------
-- Access --
------------
when Attribute_Access =>
Analyze_Access_Attribute;
Check_Not_Incomplete_Type;
-------------
-- Address --
-------------
when Attribute_Address =>
Check_E0;
Address_Checks;
Check_Not_Incomplete_Type;
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;
Check_Not_CPP_Type;
Set_Etype (N, Universal_Integer);
---------------
-- Asm_Input --
---------------
when Attribute_Asm_Input =>
Check_Asm_Attribute;
-- The back end may need to take the address of E2
if Is_Entity_Name (E2) then
Set_Address_Taken (Entity (E2));
end if;
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, Sure => True);
-- The back end may need to take the address of E2
if Is_Entity_Name (E2) then
Set_Address_Taken (Entity (E2));
end if;
Set_Etype (N, RTE (RE_Asm_Output_Operand));
-----------------------------
-- Atomic_Always_Lock_Free --
-----------------------------
when Attribute_Atomic_Always_Lock_Free =>
Check_E0;
Check_Type;
Set_Etype (N, Standard_Boolean);
----------
-- Base --
----------
-- Note: when the base attribute appears in the context of a subtype
-- mark, the analysis is done by Sem_Ch8.Find_Type, rather than by
-- the following circuit.
when Attribute_Base => Base : declare
Typ : Entity_Id;
begin
Check_E0;
Find_Type (P);
Typ := Entity (P);
if Ada_Version >= Ada_95
and then not Is_Scalar_Type (Typ)
and then not Is_Generic_Type (Typ)
then
Error_Attr_P ("prefix of Base attribute must be scalar type");
elsif Sloc (Typ) = Standard_Location
and then Base_Type (Typ) = Typ
and then Warn_On_Redundant_Constructs
then
Error_Msg_NE -- CODEFIX
("?r?redundant attribute, & is its own base type", N, Typ);
end if;
if Nkind (Parent (N)) /= N_Attribute_Reference then
Error_Msg_Name_1 := Aname;
Check_SPARK_05_Restriction
("attribute% is only allowed as prefix of another attribute", P);
end if;
Set_Etype (N, Base_Type (Entity (P)));
Set_Entity (N, Base_Type (Entity (P)));
Rewrite (N, New_Occurrence_Of (Entity (N), Loc));
Analyze (N);
end Base;
---------
-- Bit --
---------
when Attribute_Bit =>
Check_E0;
if not Is_Object_Reference (P) then
Error_Attr_P ("prefix for % attribute must be object");
-- What about the access object cases ???
else
null;
end if;
Set_Etype (N, Universal_Integer);
---------------
-- Bit_Order --
---------------
when Attribute_Bit_Order =>
Check_E0;
Check_Type;
if not Is_Record_Type (P_Type) then
Error_Attr_P ("prefix of % attribute must be record type");
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);
-- Reset incorrect indication of staticness
Set_Is_Static_Expression (N, False);
------------------
-- 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_In (P, N_Identifier, 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 =>
Check_Restriction (No_Dispatch, N);
Check_E0;
Find_Type (N);
-- Applying Class to untagged incomplete type is obsolescent in Ada
-- 2005. Note that we can't test Is_Tagged_Type here on P_Type, since
-- this flag gets set by Find_Type in this situation.
if Restriction_Check_Required (No_Obsolescent_Features)
and then Ada_Version >= Ada_2005
and then Ekind (P_Type) = E_Incomplete_Type
then
declare
DN : constant Node_Id := Declaration_Node (P_Type);
begin
if Nkind (DN) = N_Incomplete_Type_Declaration
and then not Tagged_Present (DN)
then
Check_Restriction (No_Obsolescent_Features, P);
end if;
end;
end if;
------------------
-- Code_Address --
------------------
when Attribute_Code_Address =>
Check_E0;
if Nkind (P) = N_Attribute_Reference
and then Nam_In (Attribute_Name (P), Name_Elab_Body, 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));
-- Issue an error if the prefix denotes an eliminated subprogram
else
Check_For_Eliminated_Subprogram (P, Entity (P));
end if;
Set_Etype (N, RTE (RE_Address));
----------------------
-- Compiler_Version --
----------------------
when Attribute_Compiler_Version =>
Check_E0;
Check_Standard_Prefix;
Rewrite (N, Make_String_Literal (Loc, "GNAT " & Gnat_Version_String));
Analyze_And_Resolve (N, Standard_String);
Set_Is_Static_Expression (N, True);
--------------------
-- 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
Check_Restriction (No_Obsolescent_Features, P);
if Warn_On_Obsolescent_Feature then
Error_Msg_N
("constrained for private type is an obsolescent feature "
& "(RM J.4)?j?", N);
end if;
-- If we are within an instance, the attribute must be legal
-- because it was valid in the generic unit. Ditto if this is
-- an inlining of a function declared in an instance.
if In_Instance or else In_Inlined_Body 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
-- Note: this is one of the Annex J features that does not
-- generate a warning from -gnatwj, since in fact it seems
-- very useful, and is used in the GNAT runtime.
Check_Not_Incomplete_Type;
return;
end if;
-- Normal (non-obsolescent case) of application to object of
-- a discriminated type.
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 class-wide type it 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;
-- The rule given in 3.7.2 is part of static semantics, but the
-- intent is clearly that it be treated as a legality rule, and
-- rechecked in the visible part of an instance. Nevertheless
-- the intent also seems to be it should legally apply to the
-- actual of a formal with unknown discriminants, regardless of
-- whether the actual has discriminants, in which case the value
-- of the attribute is determined using the J.4 rules. This choice
-- seems the most useful, and is compatible with existing tests.
elsif In_Instance then
return;
-- Also allow an object of a generic type if extensions allowed
-- and allow this for any type at all. (this may be obsolete ???)
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_P
("prefix of % attribute must be object of discriminated type");
---------------
-- 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_In (P, N_Identifier, 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
if not Is_Entity_Name (Prefix (P))
or else No (Entity (Prefix (P)))
or else Ekind (Entity (Prefix (P))) /= E_Entry_Family
then
if Nkind (Prefix (P)) = N_Selected_Component
and then Present (Entity (Selector_Name (Prefix (P))))
and then Ekind (Entity (Selector_Name (Prefix (P)))) =
E_Entry_Family
then
Error_Attr
("attribute % must apply to entry of current task", P);
else
Error_Attr ("invalid entry family name", P);
end if;
return;
else
Ent := Entity (Prefix (P));
end if;
elsif Nkind (P) = N_Selected_Component
and then Present (Entity (Selector_Name (P)))
and then Ekind (Entity (Selector_Name (P))) = E_Entry
then
Error_Attr
("attribute % must apply to entry of current task", P);
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_Attr
("Attribute % must apply to entry of current task", N);
end if;
end if;
exit;
elsif Ekind (Scope (Ent)) in Task_Kind
and then not Ekind_In (S, E_Block,
E_Entry,
E_Entry_Family,
E_Loop)
then
Error_Attr ("Attribute % 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;
-- Ada 2005 (AI-345): Do not consider primitive entry
-- wrappers generated for task or protected types.
elsif Ada_Version >= Ada_2005
and then not Comes_From_Source (It.Nam)
then
null;
else
Error_Attr ("ambiguous entry name", 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 : declare
Target_Default_Bit_Order : System.Bit_Order;
begin
Check_Standard_Prefix;
if Bytes_Big_Endian then
Target_Default_Bit_Order := System.High_Order_First;
else
Target_Default_Bit_Order := System.Low_Order_First;
end if;
Rewrite (N,
Make_Integer_Literal (Loc,
UI_From_Int (System.Bit_Order'Pos (Target_Default_Bit_Order))));
Set_Etype (N, Universal_Integer);
Set_Is_Static_Expression (N);
end Default_Bit_Order;
----------------------------------
-- Default_Scalar_Storage_Order --
----------------------------------
when Attribute_Default_Scalar_Storage_Order => Default_SSO : declare
RE_Default_SSO : RE_Id;
begin
Check_Standard_Prefix;
case Opt.Default_SSO is
when ' ' =>
if Bytes_Big_Endian then
RE_Default_SSO := RE_High_Order_First;
else
RE_Default_SSO := RE_Low_Order_First;
end if;
when 'H' =>
RE_Default_SSO := RE_High_Order_First;
when 'L' =>
RE_Default_SSO := RE_Low_Order_First;
when others =>
raise Program_Error;
end case;
Rewrite (N, New_Occurrence_Of (RTE (RE_Default_SSO), Loc));
end Default_SSO;
--------------
-- 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);
-----------
-- Deref --
-----------
when Attribute_Deref =>
Check_Type;
Check_E1;
Resolve (E1, RTE (RE_Address));
Set_Etype (N, P_Type);
---------------------
-- Descriptor_Size --
---------------------
when Attribute_Descriptor_Size =>
Check_E0;
if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
Error_Attr_P ("prefix of attribute % must denote a type");
end if;
Set_Etype (N, Universal_Integer);
------------
-- 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_P
("prefix of % attribute must be float or decimal type");
end if;
Set_Etype (N, Universal_Integer);
---------------
-- Elab_Body --
---------------
-- Also handles processing for Elab_Spec and Elab_Subp_Body
when Attribute_Elab_Body
| Attribute_Elab_Spec
| Attribute_Elab_Subp_Body
=>
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_Unit_Name (P);
Set_Etype (N, Standard_Boolean);
----------
-- Emax --
----------
when Attribute_Emax =>
Check_Floating_Point_Type_0;
Set_Etype (N, Universal_Integer);
-------------
-- Enabled --
-------------
when Attribute_Enabled =>
Check_Either_E0_Or_E1;
if Present (E1) then
if not Is_Entity_Name (E1) or else No (Entity (E1)) then
Error_Msg_N ("entity name expected for Enabled attribute", E1);
E1 := Empty;
end if;
end if;
if Nkind (P) /= N_Identifier then
Error_Msg_N ("identifier expected (check name)", P);
elsif Get_Check_Id (Chars (P)) = No_Check_Id then
Error_Msg_N ("& is not a recognized check name", P);
end if;
Set_Etype (N, Standard_Boolean);
--------------
-- Enum_Rep --
--------------
when Attribute_Enum_Rep =>
-- T'Enum_Rep (X) case
if Present (E1) then
Check_E1;
Check_Discrete_Type;
Resolve (E1, P_Base_Type);
-- X'Enum_Rep case. X must be an object or enumeration literal, and
-- it must be of a discrete type.
elsif not ((Is_Object_Reference (P)
or else (Is_Entity_Name (P)
and then Ekind (Entity (P)) =
E_Enumeration_Literal))
and then Is_Discrete_Type (Etype (P)))
then
Error_Attr_P ("prefix of % attribute must be discrete object");
end if;
Set_Etype (N, Universal_Integer);
--------------
-- Enum_Val --
--------------
when Attribute_Enum_Val =>
Check_E1;
Check_Type;
if not Is_Enumeration_Type (P_Type) then
Error_Attr_P ("prefix of % attribute must be enumeration type");
end if;
-- If the enumeration type has a standard representation, the effect
-- is the same as 'Val, so rewrite the attribute as a 'Val.
if not Has_Non_Standard_Rep (P_Base_Type) then
Rewrite (N,
Make_Attribute_Reference (Loc,
Prefix => Relocate_Node (Prefix (N)),
Attribute_Name => Name_Val,
Expressions => New_List (Relocate_Node (E1))));
Analyze_And_Resolve (N, P_Base_Type);
-- Non-standard representation case (enumeration with holes)
else
Check_Enum_Image;
Resolve (E1, Any_Integer);
Set_Etype (N, P_Base_Type);
end if;
-------------
-- 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_P ("prefix of % attribute must be tagged");
end if;
---------------
-- Fast_Math --
---------------
when Attribute_Fast_Math =>
Check_Standard_Prefix;
Rewrite (N, New_Occurrence_Of (Boolean_Literals (Fast_Math), Loc));
-----------------------
-- Finalization_Size --
-----------------------
when Attribute_Finalization_Size =>
Check_E0;
-- The prefix denotes an object
if Is_Object_Reference (P) then
Check_Object_Reference (P);
-- The prefix denotes a type
elsif Is_Entity_Name (P) and then Is_Type (Entity (P)) then
Check_Type;
Check_Not_Incomplete_Type;
-- Attribute 'Finalization_Size is not defined for class-wide
-- types because it is not possible to know statically whether
-- a definite type will have controlled components or not.
if Is_Class_Wide_Type (Etype (P)) then
Error_Attr_P
("prefix of % attribute cannot denote a class-wide type");
end if;
-- The prefix denotes an illegal construct
else
Error_Attr_P
("prefix of % attribute must be a definite type or an object");
end if;
Set_Etype (N, Universal_Integer);
-----------
-- First --
-----------
when Attribute_First =>
Check_Array_Or_Scalar_Type;
Bad_Attribute_For_Predicate;
---------------
-- First_Bit --
---------------
when Attribute_First_Bit =>
Check_Component;
Set_Etype (N, Universal_Integer);
-----------------
-- First_Valid --
-----------------
when Attribute_First_Valid =>
Check_First_Last_Valid;
Set_Etype (N, P_Type);
-----------------
-- 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);
--------------
-- From_Any --
--------------
when Attribute_From_Any =>
Check_E1;
Check_PolyORB_Attribute;
Set_Etype (N, P_Base_Type);
-----------------------
-- Has_Access_Values --
-----------------------
when Attribute_Has_Access_Values =>
Check_Type;
Check_E0;
Set_Etype (N, Standard_Boolean);
----------------------
-- Has_Same_Storage --
----------------------
when Attribute_Has_Same_Storage =>
Check_E1;
-- The arguments must be objects of any type
Analyze_And_Resolve (P);
Analyze_And_Resolve (E1);
Check_Object_Reference (P);
Check_Object_Reference (E1);
Set_Etype (N, Standard_Boolean);
-----------------------
-- Has_Tagged_Values --
-----------------------
when Attribute_Has_Tagged_Values =>
Check_Type;
Check_E0;
Set_Etype (N, Standard_Boolean);
-----------------------
-- 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));
-- Ada 2005 (AI-345): Attribute 'Identity may be applied to task
-- interface class-wide types.
elsif Is_Task_Type (Etype (P))
or else (Is_Access_Type (Etype (P))
and then Is_Task_Type (Designated_Type (Etype (P))))
or else (Ada_Version >= Ada_2005
and then Ekind (Etype (P)) = E_Class_Wide_Type
and then Is_Interface (Etype (P))
and then Is_Task_Interface (Etype (P)))
then
Resolve (P);
Set_Etype (N, RTE (RO_AT_Task_Id));
else
if Ada_Version >= Ada_2005 then
Error_Attr_P
("prefix of % attribute must be an exception, a task or a "
& "task interface class-wide object");
else
Error_Attr_P
("prefix of % attribute must be a task or an exception");
end if;
end if;
-----------
-- Image --
-----------
when Attribute_Image =>
Check_SPARK_05_Restriction_On_Attribute;
-- AI12-00124-1 : The ARG has adopted the GNAT semantics of 'Img for
-- scalar types, so that the prefix can be an object and not a type,
-- and there is no need for an argument. Given the vote of confidence
-- from the ARG, simplest is to transform this new usage of 'Image
-- into a reference to 'Img.
if Ada_Version > Ada_2005
and then Is_Object_Reference (P)
and then Is_Scalar_Type (P_Type)
then
if No (Expressions (N)) then
Rewrite (N,
Make_Attribute_Reference (Loc,
Prefix => Relocate_Node (P),
Attribute_Name => Name_Img));
-- If the attribute reference includes expressions, the only
-- possible interpretation is as an indexing of the parameterless
-- version of 'Image, so rewrite it accordingly.
else
Rewrite (N,
Make_Indexed_Component (Loc,
Prefix =>
Make_Attribute_Reference (Loc,
Prefix => Relocate_Node (P),
Attribute_Name => Name_Img),
Expressions => Expressions (N)));
end if;
Analyze (N);
return;
else
Check_Scalar_Type;
end if;
Set_Etype (N, Standard_String);
if Is_Real_Type (P_Type) then
if Ada_Version = 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;
-- Check restriction No_Fixed_IO. Note the check of Comes_From_Source
-- to avoid giving a duplicate message for Img expanded into Image.
if Restriction_Check_Required (No_Fixed_IO)
and then Comes_From_Source (N)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
---------
-- Img --
---------
when Attribute_Img =>
Check_E0;
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_P
("prefix of % attribute must be scalar object name");
end if;
Check_Enum_Image;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
-----------
-- Input --
-----------
when Attribute_Input =>
Check_E1;
Check_Stream_Attribute (TSS_Stream_Input);
Set_Etype (N, P_Base_Type);
-------------------
-- Integer_Value --
-------------------
when Attribute_Integer_Value =>
Check_E1;
Check_Integer_Type;
Resolve (E1, Any_Fixed);
-- Signal an error if argument type is not a specific fixed-point
-- subtype. An error has been signalled already if the argument
-- was not of a fixed-point type.
if Etype (E1) = Any_Fixed and then not Error_Posted (E1) then
Error_Attr ("argument of % must be of a fixed-point type", E1);
end if;
Set_Etype (N, P_Base_Type);
-------------------
-- Invalid_Value --
-------------------
when Attribute_Invalid_Value =>
Check_E0;
Check_Scalar_Type;
Set_Etype (N, P_Base_Type);
Invalid_Value_Used := True;
-----------
-- Large --
-----------
when Attribute_Large =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
----------
-- Last --
----------
when Attribute_Last =>
Check_Array_Or_Scalar_Type;
Bad_Attribute_For_Predicate;
--------------
-- Last_Bit --
--------------
when Attribute_Last_Bit =>
Check_Component;
Set_Etype (N, Universal_Integer);
----------------
-- Last_Valid --
----------------
when Attribute_Last_Valid =>
Check_First_Last_Valid;
Set_Etype (N, P_Type);
------------------
-- 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);
-------------------
-- Library_Level --
-------------------
when Attribute_Library_Level =>
Check_E0;
if not Is_Entity_Name (P) then
Error_Attr_P ("prefix of % attribute must be an entity name");
end if;
if not Inside_A_Generic then
Set_Boolean_Result (N,
Is_Library_Level_Entity (Entity (P)));
end if;
Set_Etype (N, Standard_Boolean);
---------------
-- Lock_Free --
---------------
when Attribute_Lock_Free =>
Check_E0;
Set_Etype (N, Standard_Boolean);
if not Is_Protected_Type (P_Type) then
Error_Attr_P
("prefix of % attribute must be a protected object");
end if;
----------------
-- Loop_Entry --
----------------
when Attribute_Loop_Entry => Loop_Entry : declare
procedure Check_References_In_Prefix (Loop_Id : Entity_Id);
-- Inspect the prefix for any uses of entities declared within the
-- related loop. Loop_Id denotes the loop identifier.
--------------------------------
-- Check_References_In_Prefix --
--------------------------------
procedure Check_References_In_Prefix (Loop_Id : Entity_Id) is
Loop_Decl : constant Node_Id := Label_Construct (Parent (Loop_Id));
function Check_Reference (Nod : Node_Id) return Traverse_Result;
-- Determine whether a reference mentions an entity declared
-- within the related loop.
function Declared_Within (Nod : Node_Id) return Boolean;
-- Determine whether Nod appears in the subtree of Loop_Decl
---------------------
-- Check_Reference --
---------------------
function Check_Reference (Nod : Node_Id) return Traverse_Result is
begin
if Nkind (Nod) = N_Identifier
and then Present (Entity (Nod))
and then Declared_Within (Declaration_Node (Entity (Nod)))
then
Error_Attr
("prefix of attribute % cannot reference local entities",
Nod);
return Abandon;
else
return OK;
end if;
end Check_Reference;
procedure Check_References is new Traverse_Proc (Check_Reference);
---------------------
-- Declared_Within --
---------------------
function Declared_Within (Nod : Node_Id) return Boolean is
Stmt : Node_Id;
begin
Stmt := Nod;
while Present (Stmt) loop
if Stmt = Loop_Decl then
return True;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Stmt) then
exit;
end if;
Stmt := Parent (Stmt);
end loop;
return False;
end Declared_Within;
-- Start of processing for Check_Prefix_For_Local_References
begin
Check_References (P);
end Check_References_In_Prefix;
-- Local variables
Context : constant Node_Id := Parent (N);
Attr : Node_Id;
Encl_Loop : Node_Id := Empty;
Encl_Prag : Node_Id := Empty;
Loop_Id : Entity_Id := Empty;
Scop : Entity_Id;
Stmt : Node_Id;
-- Start of processing for Loop_Entry
begin
Attr := N;
-- Set the type of the attribute now to ensure the successful
-- continuation of analysis even if the attribute is misplaced.
Set_Etype (Attr, P_Type);
-- Attribute 'Loop_Entry may appear in several flavors:
-- * Prefix'Loop_Entry - in this form, the attribute applies to the
-- nearest enclosing loop.
-- * Prefix'Loop_Entry (Expr) - depending on what Expr denotes, the
-- attribute may be related to a loop denoted by label Expr or
-- the prefix may denote an array object and Expr may act as an
-- indexed component.
-- * Prefix'Loop_Entry (Expr1, ..., ExprN) - the attribute applies
-- to the nearest enclosing loop, all expressions are part of
-- an indexed component.
-- * Prefix'Loop_Entry (Expr) (...) (...) - depending on what Expr
-- denotes, the attribute may be related to a loop denoted by
-- label Expr or the prefix may denote a multidimensional array
-- array object and Expr along with the rest of the expressions
-- may act as indexed components.
-- Regardless of variations, the attribute reference does not have an
-- expression list. Instead, all available expressions are stored as
-- indexed components.
-- When the attribute is part of an indexed component, find the first
-- expression as it will determine the semantics of 'Loop_Entry.
if Nkind (Context) = N_Indexed_Component then
E1 := First (Expressions (Context));
E2 := Next (E1);
-- The attribute reference appears in the following form:
-- Prefix'Loop_Entry (Exp1, Expr2, ..., ExprN) [(...)]
-- In this case, the loop name is omitted and no rewriting is
-- required.
if Present (E2) then
null;
-- The form of the attribute is:
-- Prefix'Loop_Entry (Expr) [(...)]
-- If Expr denotes a loop entry, the whole attribute and indexed
-- component will have to be rewritten to reflect this relation.
else
pragma Assert (Present (E1));
-- Do not expand the expression as it may have side effects.
-- Simply preanalyze to determine whether it is a loop name or
-- something else.
Preanalyze_And_Resolve (E1);
if Is_Entity_Name (E1)
and then Present (Entity (E1))
and then Ekind (Entity (E1)) = E_Loop
then
Loop_Id := Entity (E1);
-- Transform the attribute and enclosing indexed component
Set_Expressions (N, Expressions (Context));
Rewrite (Context, N);
Set_Etype (Context, P_Type);
Attr := Context;
end if;
end if;
end if;
-- The prefix must denote an object
if not Is_Object_Reference (P) then
Error_Attr_P ("prefix of attribute % must denote an object");
end if;
-- The prefix cannot be of a limited type because the expansion of
-- Loop_Entry must create a constant initialized by the evaluated
-- prefix.
if Is_Limited_View (Etype (P)) then
Error_Attr_P ("prefix of attribute % cannot be limited");
end if;
-- Climb the parent chain to verify the location of the attribute and
-- find the enclosing loop.
Stmt := Attr;
while Present (Stmt) loop
-- Locate the corresponding enclosing pragma. Note that in the
-- case of Assert[And_Cut] and Assume, we have already checked
-- that the pragma appears in an appropriate loop location.
if Nkind (Original_Node (Stmt)) = N_Pragma
and then Nam_In (Pragma_Name_Unmapped (Original_Node (Stmt)),
Name_Loop_Invariant,
Name_Loop_Variant,
Name_Assert,
Name_Assert_And_Cut,
Name_Assume)
then
Encl_Prag := Original_Node (Stmt);
-- Locate the enclosing loop (if any). Note that Ada 2012 array
-- iteration may be expanded into several nested loops, we are
-- interested in the outermost one which has the loop identifier,
-- and comes from source.
elsif Nkind (Stmt) = N_Loop_Statement
and then Present (Identifier (Stmt))
and then Comes_From_Source (Original_Node (Stmt))
and then Nkind (Original_Node (Stmt)) = N_Loop_Statement
then
Encl_Loop := Stmt;
-- The original attribute reference may lack a loop name. Use
-- the name of the enclosing loop because it is the related
-- loop.
if No (Loop_Id) then
Loop_Id := Entity (Identifier (Encl_Loop));
end if;
exit;
-- Prevent the search from going too far
elsif Is_Body_Or_Package_Declaration (Stmt) then
exit;
end if;
Stmt := Parent (Stmt);
end loop;
-- Loop_Entry must appear within a Loop_Assertion pragma (Assert,
-- Assert_And_Cut, Assume count as loop assertion pragmas for this
-- purpose if they appear in an appropriate location in a loop,
-- which was already checked by the top level pragma circuit).
-- Loop_Entry also denotes a value and as such can appear within an
-- expression that is an argument for another loop aspect. In that
-- case it will have been expanded into the corresponding assignment.
if Expander_Active
and then Nkind (Parent (N)) = N_Assignment_Statement
and then not Comes_From_Source (Parent (N))
then
null;
elsif No (Encl_Prag) then
Error_Attr ("attribute% must appear within appropriate pragma", N);
end if;
-- A Loop_Entry that applies to a given loop statement must not
-- appear within a body of accept statement, if this construct is
-- itself enclosed by the given loop statement.
for Index in reverse 0 .. Scope_Stack.Last loop
Scop := Scope_Stack.Table (Index).Entity;
if Ekind (Scop) = E_Loop and then Scop = Loop_Id then
exit;
elsif Ekind_In (Scop, E_Block, E_Loop, E_Return_Statement) then
null;
else
Error_Attr
("attribute % cannot appear in body or accept statement", N);
exit;
end if;
end loop;
-- The prefix cannot mention entities declared within the related
-- loop because they will not be visible once the prefix is moved
-- outside the loop.
Check_References_In_Prefix (Loop_Id);
-- The prefix must denote a static entity if the pragma does not
-- apply to the innermost enclosing loop statement, or if it appears
-- within a potentially unevaluated epxression.
if Is_Entity_Name (P)
or else Nkind (Parent (P)) = N_Object_Renaming_Declaration
or else Statically_Denotes_Object (P)
then
null;
elsif Present (Encl_Loop)
and then Entity (Identifier (Encl_Loop)) /= Loop_Id
then
Error_Attr_P
("prefix of attribute % that applies to outer loop must denote "
& "an entity");
elsif Is_Potentially_Unevaluated (P) then
Uneval_Old_Msg;
end if;
-- Replace the Loop_Entry attribute reference by its prefix if the
-- related pragma is ignored. This transformation is OK with respect
-- to typing because Loop_Entry's type is that of its prefix. This
-- early transformation also avoids the generation of a useless loop
-- entry constant.
if Present (Encl_Prag) and then Is_Ignored (Encl_Prag) then
Rewrite (N, Relocate_Node (P));
Preanalyze_And_Resolve (N);
else
Preanalyze_And_Resolve (P);
end if;
end Loop_Entry;
-------------
-- 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_Rounding --
----------------------
when Attribute_Machine_Rounding =>
Check_Floating_Point_Type_1;
Set_Etype (N, P_Base_Type);
Resolve (E1, P_Base_Type);
--------------------
-- 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 =>
Min_Max;
----------------------------------
-- Max_Alignment_For_Allocation --
----------------------------------
when Attribute_Max_Size_In_Storage_Elements =>
Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
----------------------------------
-- Max_Size_In_Storage_Elements --
----------------------------------
when Attribute_Max_Alignment_For_Allocation =>
Max_Alignment_For_Allocation_Max_Size_In_Storage_Elements;
-----------------------
-- 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_P ("prefix of % attribute must be subprogram");
end if;
Check_Either_E0_Or_E1;
if Present (E1) then
Resolve (E1, Any_Integer);
Set_Etype (E1, Standard_Integer);
if not Is_OK_Static_Expression (E1) then
Flag_Non_Static_Expr
("expression for parameter number must be static!", E1);
Error_Attr;
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 =>
Min_Max;
---------
-- Mod --
---------
when Attribute_Mod =>
-- Note: this attribute is only allowed in Ada 2005 mode, but
-- we do not need to test that here, since Mod is only recognized
-- as an attribute name in Ada 2005 mode during the parse.
Check_E1;
Check_Modular_Integer_Type;
Resolve (E1, Any_Integer);
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_Modular_Integer_Type;
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 : constant Entity_Id := Ultimate_Alias (Proc_Ent);
begin
-- 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) in N_Subprogram_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) in N_Subprogram_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);
---------
-- Old --
---------
when Attribute_Old => Old : declare
procedure Check_References_In_Prefix (Subp_Id : Entity_Id);
-- Inspect the contents of the prefix and detect illegal uses of a
-- nested 'Old, attribute 'Result or a use of an entity declared in
-- the related postcondition expression. Subp_Id is the subprogram to
-- which the related postcondition applies.
--------------------------------
-- Check_References_In_Prefix --
--------------------------------
procedure Check_References_In_Prefix (Subp_Id : Entity_Id) is
function Check_Reference (Nod : Node_Id) return Traverse_Result;
-- Detect attribute 'Old, attribute 'Result of a use of an entity
-- and perform the appropriate semantic check.
---------------------
-- Check_Reference --
---------------------
function Check_Reference (Nod : Node_Id) return Traverse_Result is
begin
-- Attributes 'Old and 'Result cannot appear in the prefix of
-- another attribute 'Old.
if Nkind (Nod) = N_Attribute_Reference
and then Nam_In (Attribute_Name (Nod), Name_Old,
Name_Result)
then
Error_Msg_Name_1 := Attribute_Name (Nod);
Error_Msg_Name_2 := Name_Old;
Error_Msg_N
("attribute % cannot appear in the prefix of attribute %",
Nod);
return Abandon;
-- Entities mentioned within the prefix of attribute 'Old must
-- be global to the related postcondition. If this is not the
-- case, then the scope of the local entity is nested within
-- that of the subprogram.
elsif Is_Entity_Name (Nod)
and then Present (Entity (Nod))
and then Scope_Within (Scope (Entity (Nod)), Subp_Id)
then
Error_Attr
("prefix of attribute % cannot reference local entities",
Nod);
return Abandon;
-- Otherwise keep inspecting the prefix
else
return OK;
end if;
end Check_Reference;
procedure Check_References is new Traverse_Proc (Check_Reference);
-- Start of processing for Check_References_In_Prefix
begin
Check_References (P);
end Check_References_In_Prefix;
-- Local variables
Legal : Boolean;
Pref_Id : Entity_Id;
Pref_Typ : Entity_Id;
Spec_Id : Entity_Id;
-- Start of processing for Old
begin
-- The attribute reference is a primary. If any expressions follow,
-- then the attribute reference is an indexable object. Transform the
-- attribute into an indexed component and analyze it.
if Present (E1) then
Rewrite (N,
Make_Indexed_Component (Loc,
Prefix =>
Make_Attribute_Reference (Loc,
Prefix => Relocate_Node (P),
Attribute_Name => Name_Old),
Expressions => Expressions (N)));
Analyze (N);
return;
end if;
Analyze_Attribute_Old_Result (Legal, Spec_Id);
-- The aspect or pragma where attribute 'Old resides should be
-- associated with a subprogram declaration or a body. If this is not
-- the case, then the aspect or pragma is illegal. Return as analysis
-- cannot be carried out.
-- The exception to this rule is when generating C since in this case
-- postconditions are inlined.
if No (Spec_Id)
and then Modify_Tree_For_C
and then In_Inlined_Body
then
Spec_Id := Entity (P);
elsif not Legal then
return;
end if;
-- The prefix must be preanalyzed as the full analysis will take
-- place during expansion.
Preanalyze_And_Resolve (P);
-- Ensure that the prefix does not contain attributes 'Old or 'Result
Check_References_In_Prefix (Spec_Id);
-- Set the type of the attribute now to prevent cascaded errors
Pref_Typ := Etype (P);
Set_Etype (N, Pref_Typ);
-- Legality checks
if Is_Limited_Type (Pref_Typ) then
Error_Attr ("attribute % cannot apply to limited objects", P);
end if;
-- The prefix is a simple name
if Is_Entity_Name (P) and then Present (Entity (P)) then
Pref_Id := Entity (P);
-- Emit a warning when the prefix is a constant. Note that the use
-- of Error_Attr would reset the type of N to Any_Type even though
-- this is a warning. Use Error_Msg_XXX instead.
if Is_Constant_Object (Pref_Id) then
Error_Msg_Name_1 := Name_Old;
Error_Msg_N
("??attribute % applied to constant has no effect", P);
end if;
-- Otherwise the prefix is not a simple name
else
-- Ensure that the prefix of attribute 'Old is an entity when it
-- is potentially unevaluated (6.1.1 (27/3)).
if Is_Potentially_Unevaluated (N)
and then not Statically_Denotes_Object (P)
then
Uneval_Old_Msg;
-- Detect a possible infinite recursion when the prefix denotes
-- the related function.
-- function Func (...) return ...
-- with Post => Func'Old ...;
-- The function may be specified in qualified form X.Y where X is
-- a protected object and Y is a protected function. In that case
-- ensure that the qualified form has an entity.
elsif Nkind (P) = N_Function_Call
and then Nkind (Name (P)) in N_Has_Entity
then
Pref_Id := Entity (Name (P));
if Ekind_In (Spec_Id, E_Function, E_Generic_Function)
and then Pref_Id = Spec_Id
then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N ("!possible infinite recursion<<", P);
Error_Msg_N ("\!??Storage_Error ]<<", P);
end if;
end if;
-- The prefix of attribute 'Old may refer to a component of a
-- formal parameter. In this case its expansion may generate
-- actual subtypes that are referenced in an inner context and
-- that must be elaborated within the subprogram itself. If the
-- prefix includes a function call, it may involve finalization
-- actions that should be inserted when the attribute has been
-- rewritten as a declaration. Create a declaration for the prefix
-- and insert it at the start of the enclosing subprogram. This is
-- an expansion activity that has to be performed now to prevent
-- out-of-order issues.
-- This expansion is both harmful and not needed in SPARK mode,
-- since the formal verification back end relies on the types of
-- nodes (hence is not robust w.r.t. a change to base type here),
-- and does not suffer from the out-of-order issue described
-- above. Thus, this expansion is skipped in SPARK mode.
-- The expansion is not relevant for discrete types, which will
-- not generate extra declarations, and where use of the base type
-- may lead to spurious errors if context is a case.
if not GNATprove_Mode then
if not Is_Discrete_Type (Pref_Typ) then
Pref_Typ := Base_Type (Pref_Typ);
end if;
Set_Etype (N, Pref_Typ);
Set_Etype (P, Pref_Typ);
Analyze_Dimension (N);
Expand (N);
end if;
end if;
end Old;
----------------------
-- Overlaps_Storage --
----------------------
when Attribute_Overlaps_Storage =>
Check_E1;
-- Both arguments must be objects of any type
Analyze_And_Resolve (P);
Analyze_And_Resolve (E1);
Check_Object_Reference (P);
Check_Object_Reference (E1);
Set_Etype (N, Standard_Boolean);
------------
-- Output --
------------
when Attribute_Output =>
Check_E2;
Check_Stream_Attribute (TSS_Stream_Output);
Set_Etype (N, Standard_Void_Type);
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_P
("prefix of % attribute must be library-level entity");
-- The defining entity of prefix should not be declared inside a
-- Pure unit. RM E.1(8). Is_Pure was set during declaration.
elsif Is_Entity_Name (P)
and then Is_Pure (Entity (P))
then
Error_Attr_P ("prefix of% attribute must not be declared pure");
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);
------------------
-- Pool_Address --
------------------
when Attribute_Pool_Address =>
Check_E0;
Set_Etype (N, RTE (RE_Address));
---------
-- Pos --
---------
when Attribute_Pos =>
Check_Discrete_Type;
Check_E1;
if Is_Boolean_Type (P_Type) then
Error_Msg_Name_1 := Aname;
Error_Msg_Name_2 := Chars (P_Type);
Check_SPARK_05_Restriction
("attribute% is not allowed for type%", P);
end if;
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;
if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
Error_Msg_Name_1 := Aname;
Error_Msg_Name_2 := Chars (P_Type);
Check_SPARK_05_Restriction
("attribute% is not allowed for type%", P);
end if;
Resolve (E1, P_Base_Type);
Set_Etype (N, P_Base_Type);
-- Since Pred works on the base type, we normally do no check for the
-- floating-point case, since the base type is unconstrained. But we
-- make an exception in Check_Float_Overflow mode.
if Is_Floating_Point_Type (P_Type) then
if not Range_Checks_Suppressed (P_Base_Type) then
Set_Do_Range_Check (E1);
end if;
-- 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;
--------------
-- Priority --
--------------
-- Ada 2005 (AI-327): Dynamic ceiling priorities
when Attribute_Priority =>
if Ada_Version < Ada_2005 then
Error_Attr ("% attribute is allowed only in Ada 2005 mode", P);
end if;
Check_E0;
Check_Restriction (No_Dynamic_Priorities, N);
-- The prefix must be a protected object (AARM D.5.2 (2/2))
Analyze (P);
if Is_Protected_Type (Etype (P))
or else (Is_Access_Type (Etype (P))
and then Is_Protected_Type (Designated_Type (Etype (P))))
then
Resolve (P, Etype (P));
else
Error_Attr_P ("prefix of % attribute must be a protected object");
end if;
Set_Etype (N, Standard_Integer);
-- Must be called from within a protected procedure or entry of the
-- protected object.
declare
S : Entity_Id;
begin
S := Current_Scope;
while S /= Etype (P)
and then S /= Standard_Standard
loop
S := Scope (S);
end loop;
if S = Standard_Standard then
Error_Attr ("the attribute % is only allowed inside protected "
& "operations", P);
end if;
end;
Validate_Non_Static_Attribute_Function_Call;
-----------
-- Range --
-----------
when Attribute_Range =>
Check_Array_Or_Scalar_Type;
Bad_Attribute_For_Predicate;
if Ada_Version = 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;
------------
-- Result --
------------
when Attribute_Result => Result : declare
function Denote_Same_Function
(Pref_Id : Entity_Id;
Spec_Id : Entity_Id) return Boolean;
-- Determine whether the entity of the prefix Pref_Id denotes the
-- same entity as that of the related subprogram Spec_Id.
--------------------------
-- Denote_Same_Function --
--------------------------
function Denote_Same_Function
(Pref_Id : Entity_Id;
Spec_Id : Entity_Id) return Boolean
is
Over_Id : constant Entity_Id := Overridden_Operation (Spec_Id);
Subp_Spec : constant Node_Id := Parent (Spec_Id);
begin
-- The prefix denotes the related subprogram
if Pref_Id = Spec_Id then
return True;
-- Account for a special case when attribute 'Result appears in
-- the postcondition of a generic function.
-- generic
-- function Gen_Func return ...
-- with Post => Gen_Func'Result ...;
-- When the generic function is instantiated, the Chars field of
-- the instantiated prefix still denotes the name of the generic
-- function. Note that any preemptive transformation is impossible
-- without a proper analysis. The structure of the wrapper package
-- is as follows:
-- package Anon_Gen_Pack is
-- <subtypes and renamings>
-- function Subp_Decl return ...; -- (!)
-- pragma Postcondition (Gen_Func'Result ...); -- (!)
-- function Gen_Func ... renames Subp_Decl;
-- end Anon_Gen_Pack;
elsif Nkind (Subp_Spec) = N_Function_Specification
and then Present (Generic_Parent (Subp_Spec))
and then Ekind_In (Pref_Id, E_Generic_Function, E_Function)
then
if Generic_Parent (Subp_Spec) = Pref_Id then
return True;
elsif Present (Alias (Pref_Id))
and then Alias (Pref_Id) = Spec_Id
then
return True;
end if;
-- Account for a special case where a primitive of a tagged type
-- inherits a class-wide postcondition from a parent type. In this
-- case the prefix of attribute 'Result denotes the overriding
-- primitive.
elsif Present (Over_Id) and then Pref_Id = Over_Id then
return True;
end if;
-- Otherwise the prefix does not denote the related subprogram
return False;
end Denote_Same_Function;
-- Local variables
In_Inlined_C_Postcondition : constant Boolean :=
Modify_Tree_For_C
and then In_Inlined_Body;
Legal : Boolean;
Pref_Id : Entity_Id;
Spec_Id : Entity_Id;
-- Start of processing for Result
begin
-- The attribute reference is a primary. If any expressions follow,
-- then the attribute reference is an indexable object. Transform the
-- attribute into an indexed component and analyze it.
if Present (E1) then
Rewrite (N,
Make_Indexed_Component (Loc,
Prefix =>
Make_Attribute_Reference (Loc,
Prefix => Relocate_Node (P),
Attribute_Name => Name_Result),
Expressions => Expressions (N)));
Analyze (N);
return;
end if;
Analyze_Attribute_Old_Result (Legal, Spec_Id);
-- The aspect or pragma where attribute 'Result resides should be
-- associated with a subprogram declaration or a body. If this is not
-- the case, then the aspect or pragma is illegal. Return as analysis
-- cannot be carried out.
-- The exception to this rule is when generating C since in this case
-- postconditions are inlined.
if No (Spec_Id) and then In_Inlined_C_Postcondition then
Spec_Id := Entity (P);
elsif not Legal then
return;
end if;
-- Attribute 'Result is part of a _Postconditions procedure. There is
-- no need to perform the semantic checks below as they were already
-- verified when the attribute was analyzed in its original context.
-- Instead, rewrite the attribute as a reference to formal parameter
-- _Result of the _Postconditions procedure.
if Chars (Spec_Id) = Name_uPostconditions
or else
(In_Inlined_C_Postcondition
and then Nkind (Parent (Spec_Id)) = N_Block_Statement)
then
Rewrite (N, Make_Identifier (Loc, Name_uResult));
-- The type of formal parameter _Result is that of the function
-- encapsulating the _Postconditions procedure. Resolution must
-- be carried out against the function return type.
Analyze_And_Resolve (N, Etype (Scope (Spec_Id)));
-- Otherwise attribute 'Result appears in its original context and
-- all semantic checks should be carried out.
else
-- Verify the legality of the prefix. It must denotes the entity
-- of the related [generic] function.
if Is_Entity_Name (P) then
Pref_Id := Entity (P);
if Ekind_In (Pref_Id, E_Function, E_Generic_Function)
and then Ekind (Spec_Id) = Ekind (Pref_Id)
then
if Denote_Same_Function (Pref_Id, Spec_Id) then
-- Correct the prefix of the attribute when the context
-- is a generic function.
if Pref_Id /= Spec_Id then
Rewrite (P, New_Occurrence_Of (Spec_Id, Loc));
Analyze (P);
end if;
Set_Etype (N, Etype (Spec_Id));
-- Otherwise the prefix denotes some unrelated function
else
Error_Msg_Name_2 := Chars (Spec_Id);
Error_Attr
("incorrect prefix for attribute %, expected %", P);
end if;
-- Otherwise the prefix denotes some other form of subprogram
-- entity.
else
Error_Attr
("attribute % can only appear in postcondition of "
& "function", P);
end if;
-- Otherwise the prefix is illegal
else
Error_Msg_Name_2 := Chars (Spec_Id);
Error_Attr ("incorrect prefix for attribute %, expected %", P);
end if;
end if;
end Result;
------------------
-- Range_Length --
------------------
when Attribute_Range_Length =>
Check_E0;
Check_Discrete_Type;
Set_Etype (N, Universal_Integer);
----------
-- Read --
----------
when Attribute_Read =>
Check_E2;
Check_Stream_Attribute (TSS_Stream_Read);
Set_Etype (N, Standard_Void_Type);
Resolve (N, Standard_Void_Type);
Note_Possible_Modification (E2, Sure => True);
---------
-- Ref --
---------
when Attribute_Ref =>
Check_E1;
Analyze (P);
if Nkind (P) /= N_Expanded_Name
or else not Is_RTE (P_Type, RE_Address)
then
Error_Attr_P ("prefix of % attribute must be System.Address");
end if;
Analyze_And_Resolve (E1, Any_Integer);
Set_Etype (N, RTE (RE_Address));
---------------
-- 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);
---------------------
-- Restriction_Set --
---------------------
when Attribute_Restriction_Set => Restriction_Set : declare
R : Restriction_Id;
U : Node_Id;
Unam : Unit_Name_Type;
begin
Check_E1;
Analyze (P);
Check_System_Prefix;
-- No_Dependence case
if Nkind (E1) = N_Parameter_Association then
pragma Assert (Chars (Selector_Name (E1)) = Name_No_Dependence);
U := Explicit_Actual_Parameter (E1);
if not OK_No_Dependence_Unit_Name (U) then
Set_Boolean_Result (N, False);
Error_Attr;
end if;
-- See if there is an entry already in the table. That's the
-- case in which we can return True.
for J in No_Dependences.First .. No_Dependences.Last loop
if Designate_Same_Unit (U, No_Dependences.Table (J).Unit)
and then No_Dependences.Table (J).Warn = False
then
Set_Boolean_Result (N, True);
return;
end if;
end loop;
-- If not in the No_Dependence table, result is False
Set_Boolean_Result (N, False);
-- In this case, we must ensure that the binder will reject any
-- other unit in the partition that sets No_Dependence for this
-- unit. We do that by making an entry in the special table kept
-- for this purpose (if the entry is not there already).
Unam := Get_Spec_Name (Get_Unit_Name (U));
for J in Restriction_Set_Dependences.First ..
Restriction_Set_Dependences.Last
loop
if Restriction_Set_Dependences.Table (J) = Unam then
return;
end if;
end loop;
Restriction_Set_Dependences.Append (Unam);
-- Normal restriction case
else
if Nkind (E1) /= N_Identifier then
Set_Boolean_Result (N, False);
Error_Attr ("attribute % requires restriction identifier", E1);
else
R := Get_Restriction_Id (Process_Restriction_Synonyms (E1));
if R = Not_A_Restriction_Id then
Set_Boolean_Result (N, False);
Error_Msg_Node_1 := E1;
Error_Attr ("invalid restriction identifier &", E1);
elsif R not in Partition_Boolean_Restrictions then
Set_Boolean_Result (N, False);
Error_Msg_Node_1 := E1;
Error_Attr
("& is not a boolean partition-wide restriction", E1);
end if;
if Restriction_Active (R) then
Set_Boolean_Result (N, True);
else
Check_Restriction (R, N);
Set_Boolean_Result (N, False);
end if;
end if;
end if;
end Restriction_Set;
-----------
-- 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);
--------------------------
-- Scalar_Storage_Order --
--------------------------
when Attribute_Scalar_Storage_Order => Scalar_Storage_Order : declare
Ent : Entity_Id := Empty;
begin
Check_E0;
Check_Type;
if not (Is_Record_Type (P_Type) or else Is_Array_Type (P_Type)) then
-- In GNAT mode, the attribute applies to generic types as well
-- as composite types, and for non-composite types always returns
-- the default bit order for the target.
if not (GNAT_Mode and then Is_Generic_Type (P_Type))
and then not In_Instance
then
Error_Attr_P
("prefix of % attribute must be record or array type");
elsif not Is_Generic_Type (P_Type) then
if Bytes_Big_Endian then
Ent := RTE (RE_High_Order_First);
else
Ent := RTE (RE_Low_Order_First);
end if;
end if;
elsif Bytes_Big_Endian xor Reverse_Storage_Order (P_Type) then
Ent := RTE (RE_High_Order_First);
else
Ent := RTE (RE_Low_Order_First);
end if;
if Present (Ent) then
Rewrite (N, New_Occurrence_Of (Ent, Loc));
end if;
Set_Etype (N, RTE (RE_Bit_Order));
Resolve (N);
-- Reset incorrect indication of staticness
Set_Is_Static_Expression (N, False);
end Scalar_Storage_Order;
-----------
-- 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 prefix is parameterless function call, rewrite and resolve
-- as such.
if Is_Entity_Name (P)
and then Ekind (Entity (P)) = E_Function
then
Resolve (P);
-- Similar processing for a protected function call
elsif Nkind (P) = N_Selected_Component
and then Ekind (Entity (Selector_Name (P))) = E_Function
then
Resolve (P);
end if;
if Is_Object_Reference (P) then
Check_Object_Reference (P);
elsif Is_Entity_Name (P)
and then (Is_Type (Entity (P))
or else Ekind (Entity (P)) = E_Enumeration_Literal)
then
null;
elsif Nkind (P) = N_Type_Conversion
and then not Comes_From_Source (P)
then
null;
-- Some other compilers allow dubious use of X'???'Size
elsif Relaxed_RM_Semantics
and then Nkind (P) = N_Attribute_Reference
then
null;
else
Error_Attr_P ("invalid prefix for % attribute");
end if;
Check_Not_Incomplete_Type;
Check_Not_CPP_Type;
Set_Etype (N, Universal_Integer);
-- If we are processing pragmas Compile_Time_Warning and Compile_
-- Time_Errors after the back end has been called and this occurrence
-- of 'Size is known at compile time then it is safe to perform this
-- evaluation. Needed to perform the static evaluation of the full
-- boolean expression of these pragmas.
if In_Compile_Time_Warning_Or_Error
and then Is_Entity_Name (P)
and then (Is_Type (Entity (P))
or else Ekind (Entity (P)) = E_Enumeration_Literal)
and then Size_Known_At_Compile_Time (Entity (P))
then
Rewrite (N, Make_Integer_Literal (Sloc (N), Esize (Entity (P))));
Analyze (N);
end if;
-----------
-- Small --
-----------
when Attribute_Small =>
Check_E0;
Check_Real_Type;
Set_Etype (N, Universal_Real);
------------------
-- Storage_Pool --
------------------
when Attribute_Storage_Pool
| Attribute_Simple_Storage_Pool
=>
Check_E0;
if Is_Access_Type (P_Type) then
if Ekind (P_Type) = E_Access_Subprogram_Type then
Error_Attr_P
("cannot use % attribute for access-to-subprogram type");
end if;
-- 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;
if Attr_Id = Attribute_Storage_Pool then
if Present (Get_Rep_Pragma (Etype (Entity (N)),
Name_Simple_Storage_Pool_Type))
then
Error_Msg_Name_1 := Aname;
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_N
("cannot use % attribute for type with simple storage "
& "pool<<", N);
Error_Msg_N ("\Program_Error [<<", N);
Rewrite
(N, Make_Raise_Program_Error
(Sloc (N), Reason => PE_Explicit_Raise));
end if;
Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool)));
-- In the Simple_Storage_Pool case, verify that the pool entity is
-- actually of a simple storage pool type, and set the attribute's
-- type to the pool object's type.
else
if not Present (Get_Rep_Pragma (Etype (Entity (N)),
Name_Simple_Storage_Pool_Type))
then
Error_Attr_P
("cannot use % attribute for type without simple " &
"storage pool");
end if;
Set_Etype (N, Etype (Entity (N)));
end if;
-- 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_P ("prefix of % attribute must be access type");
end if;
------------------
-- Storage_Size --
------------------
when Attribute_Storage_Size =>
Check_E0;
if Is_Task_Type (P_Type) then
Set_Etype (N, Universal_Integer);
-- Use with tasks is an obsolescent feature
Check_Restriction (No_Obsolescent_Features, P);
elsif Is_Access_Type (P_Type) then
if Ekind (P_Type) = E_Access_Subprogram_Type then
Error_Attr_P
("cannot use % attribute for access-to-subprogram type");
end if;
if Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
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_Task_Prefix;
Set_Etype (N, Universal_Integer);
end if;
else
Error_Attr_P ("prefix of % attribute must be access or task type");
end if;
------------------
-- Storage_Unit --
------------------
when Attribute_Storage_Unit =>
Standard_Attribute (Ttypes.System_Storage_Unit);
-----------------
-- Stream_Size --
-----------------
when Attribute_Stream_Size =>
Check_E0;
Check_Type;
if Is_Entity_Name (P)
and then Is_Elementary_Type (Entity (P))
then
Set_Etype (N, Universal_Integer);
else
Error_Attr_P ("invalid prefix for % attribute");
end if;
---------------
-- Stub_Type --
---------------
when Attribute_Stub_Type =>
Check_Type;
Check_E0;
if Is_Remote_Access_To_Class_Wide_Type (Base_Type (P_Type)) then
-- For a real RACW [sub]type, use corresponding stub type
if not Is_Generic_Type (P_Type) then
Rewrite (N,
New_Occurrence_Of
(Corresponding_Stub_Type (Base_Type (P_Type)), Loc));
-- For a generic type (that has been marked as an RACW using the
-- Remote_Access_Type aspect or pragma), use a generic RACW stub
-- type. Note that if the actual is not a remote access type, the
-- instantiation will fail.
else
-- Note: we go to the underlying type here because the view
-- returned by RTE (RE_RACW_Stub_Type) might be incomplete.
Rewrite (N,
New_Occurrence_Of
(Underlying_Type (RTE (RE_RACW_Stub_Type)), Loc));
end if;
else
Error_Attr_P
("prefix of% attribute must be remote access-to-class-wide");
end if;
----------
-- Succ --
----------
when Attribute_Succ =>
Check_Scalar_Type;
Check_E1;
if Is_Real_Type (P_Type) or else Is_Boolean_Type (P_Type) then
Error_Msg_Name_1 := Aname;
Error_Msg_Name_2 := Chars (P_Type);
Check_SPARK_05_Restriction
("attribute% is not allowed for type%", P);
end if;
Resolve (E1, P_Base_Type);
Set_Etype (N, P_Base_Type);
-- Since Pred works on the base type, we normally do no check for the
-- floating-point case, since the base type is unconstrained. But we
-- make an exception in Check_Float_Overflow mode.
if Is_Floating_Point_Type (P_Type) then
if not Range_Checks_Suppressed (P_Base_Type) then
Set_Do_Range_Check (E1);
end if;
-- 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;
--------------------------------
-- System_Allocator_Alignment --
--------------------------------
when Attribute_System_Allocator_Alignment =>
Standard_Attribute (Ttypes.System_Allocator_Alignment);
---------
-- Tag --
---------
when Attribute_Tag =>
Check_E0;
Check_Dereference;
if not Is_Tagged_Type (P_Type) then
Error_Attr_P ("prefix of % attribute must be tagged");
-- 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_P
("% attribute can only be applied to objects " &
"of class - wide type");
end if;
-- The prefix cannot be an incomplete type. However, references to
-- 'Tag can be generated when expanding interface conversions, and
-- this is legal.
if Comes_From_Source (N) then
Check_Not_Incomplete_Type;
end if;
-- Set appropriate type
Set_Etype (N, RTE (RE_Tag));
-----------------
-- Target_Name --
-----------------
when Attribute_Target_Name => Target_Name : declare
TN : constant String := Sdefault.Target_Name.all;
TL : Natural;
begin
Check_Standard_Prefix;
TL := TN'Last;
if TN (TL) = '/' or else TN (TL) = '\' then
TL := TL - 1;
end if;
Rewrite (N,
Make_String_Literal (Loc,
Strval => TN (TN'First .. TL)));
Analyze_And_Resolve (N, Standard_String);
Set_Is_Static_Expression (N, True);
end Target_Name;
----------------
-- Terminated --
----------------
when Attribute_Terminated =>
Check_E0;
Set_Etype (N, Standard_Boolean);
Check_Task_Prefix;
----------------
-- To_Address --
----------------
when Attribute_To_Address => To_Address : declare
Val : Uint;
begin
Check_E1;
Analyze (P);
Check_System_Prefix;
Generate_Reference (RTE (RE_Address), P);
Analyze_And_Resolve (E1, Any_Integer);
Set_Etype (N, RTE (RE_Address));
if Is_Static_Expression (E1) then
Set_Is_Static_Expression (N, True);
end if;
-- OK static expression case, check range and set appropriate type
if Is_OK_Static_Expression (E1) then
Val := Expr_Value (E1);
if Val < -(2 ** UI_From_Int (Standard'Address_Size - 1))
or else
Val > 2 ** UI_From_Int (Standard'Address_Size) - 1
then
Error_Attr ("address value out of range for % attribute", E1);
end if;
-- In most cases the expression is a numeric literal or some other
-- address expression, but if it is a declared constant it may be
-- of a compatible type that must be left on the node.
if Is_Entity_Name (E1) then
null;
-- Set type to universal integer if negative
elsif Val < 0 then
Set_Etype (E1, Universal_Integer);
-- Otherwise set type to Unsigned_64 to accommodate max values
else
Set_Etype (E1, Standard_Unsigned_64);
end if;
end if;
Set_Is_Static_Expression (N, True);
end To_Address;
------------
-- To_Any --
------------
when Attribute_To_Any =>
Check_E1;
Check_PolyORB_Attribute;
Set_Etype (N, RTE (RE_Any));
----------------
-- 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));
--------------
-- TypeCode --
--------------
when Attribute_TypeCode =>
Check_E0;
Check_PolyORB_Attribute;
Set_Etype (N, RTE (RE_TypeCode));
--------------
-- Type_Key --
--------------
when Attribute_Type_Key => Type_Key : declare
Full_Name : constant String_Id :=
Fully_Qualified_Name_String (Entity (P));
CRC : CRC32;
-- The computed signature for the type
Deref : Boolean;
-- To simplify the handling of mutually recursive types, follow a
-- single dereference link in a composite type.
procedure Compute_Type_Key (T : Entity_Id);
-- Create a CRC integer from the declaration of the type. For a
-- composite type, fold in the representation of its components in
-- recursive fashion. We use directly the source representation of
-- the types involved.
----------------------
-- Compute_Type_Key --
----------------------
procedure Compute_Type_Key (T : Entity_Id) is
Buffer : Source_Buffer_Ptr;
P_Max : Source_Ptr;
P_Min : Source_Ptr;
Rep : Node_Id;
SFI : Source_File_Index;
procedure Process_One_Declaration;
-- Update CRC with the characters of one type declaration, or a
-- representation pragma that applies to the type.
-----------------------------
-- Process_One_Declaration --
-----------------------------
procedure Process_One_Declaration is
begin
-- Scan type declaration, skipping blanks
for Ptr in P_Min .. P_Max loop
if Buffer (Ptr) /= ' ' then
System.CRC32.Update (CRC, Buffer (Ptr));
end if;
end loop;
end Process_One_Declaration;
-- Start of processing for Compute_Type_Key
begin
if Is_Itype (T) then
return;
end if;
-- If the type is declared in Standard, there is no source, so
-- just use its name.
if Scope (T) = Standard_Standard then
declare
Name : constant String := Get_Name_String (Chars (T));
begin
for J in Name'Range loop
System.CRC32.Update (CRC, Name (J));
end loop;
end;
return;
end if;
Sloc_Range (Enclosing_Declaration (T), P_Min, P_Max);
SFI := Get_Source_File_Index (P_Min);
pragma Assert (SFI = Get_Source_File_Index (P_Max));
Buffer := Source_Text (SFI);
Process_One_Declaration;
-- Recurse on relevant component types
if Is_Array_Type (T) then
Compute_Type_Key (Component_Type (T));
elsif Is_Access_Type (T) then
if not Deref then
Deref := True;
Compute_Type_Key (Designated_Type (T));
end if;
elsif Is_Derived_Type (T) then
Compute_Type_Key (Etype (T));
elsif Is_Record_Type (T) then
declare
Comp : Entity_Id;
begin
Comp := First_Component (T);
while Present (Comp) loop
Compute_Type_Key (Etype (Comp));
Next_Component (Comp);
end loop;
end;
end if;
if Is_First_Subtype (T) then
-- Fold in representation aspects for the type, which appear in
-- the same source buffer. If the representation aspects are in
-- a different source file, then skip them; they apply to some
-- other type, perhaps one we're derived from.
Rep := First_Rep_Item (T);
while Present (Rep) loop
if Comes_From_Source (Rep) then
Sloc_Range (Rep, P_Min, P_Max);
if SFI = Get_Source_File_Index (P_Min) then
pragma Assert (SFI = Get_Source_File_Index (P_Max));
Process_One_Declaration;
end if;
end if;
Rep := Next_Rep_Item (Rep);
end loop;
end if;
end Compute_Type_Key;
-- Start of processing for Type_Key
begin
Check_E0;
Check_Type;
Start_String;
Deref := False;
-- Copy all characters in Full_Name but the trailing NUL
for J in 1 .. String_Length (Full_Name) - 1 loop
Store_String_Char (Get_String_Char (Full_Name, Pos (J)));
end loop;
-- Compute CRC and convert it to string one character at a time, so
-- as not to use Image within the compiler.
Initialize (CRC);
Compute_Type_Key (Entity (P));
if not Is_Frozen (Entity (P)) then
Error_Msg_N ("premature usage of Type_Key?", N);
end if;
while CRC > 0 loop
Store_String_Char (Character'Val (48 + (CRC rem 10)));
CRC := CRC / 10;
end loop;
Rewrite (N, Make_String_Literal (Loc, End_String));
Analyze_And_Resolve (N, Standard_String);
end Type_Key;
-----------------------
-- 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;
Analyze_Access_Attribute;
Check_Not_Incomplete_Type;
-------------------------
-- Unconstrained_Array --
-------------------------
when Attribute_Unconstrained_Array =>
Check_E0;
Check_Type;
Check_Not_Incomplete_Type;
Set_Etype (N, Standard_Boolean);
Set_Is_Static_Expression (N, True);
------------------------------
-- 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 =>
Check_E0;
if not Is_Entity_Name (P)
or else Ekind (Entity (P)) not in Named_Kind
then
Error_Attr_P ("prefix for % attribute must be named number");
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 not Nkind_In (Expr, N_Integer_Literal, 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);
Set_Is_Static_Expression (N, True);
end;
end if;
-------------------------
-- Unrestricted_Access --
-------------------------
-- This is a GNAT specific attribute which is like Access except that
-- all scope checks and checks for aliased views are omitted. It is
-- documented as being equivalent to the use of the Address attribute
-- followed by an unchecked conversion to the target access type.
when Attribute_Unrestricted_Access =>
-- If from source, deal with relevant restrictions
if Comes_From_Source (N) then
Check_Restriction (No_Unchecked_Access, N);
if Nkind (P) in N_Has_Entity
and then Present (Entity (P))
and then Is_Object (Entity (P))
then
Check_Restriction (No_Implicit_Aliasing, N);
end if;
end if;
if Is_Entity_Name (P) then
Set_Address_Taken (Entity (P));
end if;
-- It might seem reasonable to call Address_Checks here to apply the
-- same set of semantic checks that we enforce for 'Address (after
-- all we document Unrestricted_Access as being equivalent to the
-- use of Address followed by an Unchecked_Conversion). However, if
-- we do enable these checks, we get multiple failures in both the
-- compiler run-time and in our regression test suite, so we leave
-- out these checks for now. To be investigated further some time???
-- Address_Checks;
-- Now complete analysis using common access processing
Analyze_Access_Attribute;
------------
-- Update --
------------
when Attribute_Update => Update : declare
Common_Typ : Entity_Id;
-- The common type of a multiple component update for a record
Comps : Elist_Id := No_Elist;
-- A list used in the resolution of a record update. It contains the
-- entities of all record components processed so far.
procedure Analyze_Array_Component_Update (Assoc : Node_Id);
-- Analyze and resolve array_component_association Assoc against the
-- index of array type P_Type.
procedure Analyze_Record_Component_Update (Comp : Node_Id);
-- Analyze and resolve record_component_association Comp against
-- record type P_Type.
------------------------------------
-- Analyze_Array_Component_Update --
------------------------------------
procedure Analyze_Array_Component_Update (Assoc : Node_Id) is
Expr : Node_Id;
High : Node_Id;
Index : Node_Id;
Index_Typ : Entity_Id;
Low : Node_Id;
begin
-- The current association contains a sequence of indexes denoting
-- an element of a multidimensional array:
-- (Index_1, ..., Index_N)
-- Examine each individual index and resolve it against the proper
-- index type of the array.
if Nkind (First (Choices (Assoc))) = N_Aggregate then
Expr := First (Choices (Assoc));
while Present (Expr) loop
-- The use of others is illegal (SPARK RM 4.4.1(12))
if Nkind (Expr) = N_Others_Choice then
Error_Attr
("others choice not allowed in attribute %", Expr);
-- Otherwise analyze and resolve all indexes
else
Index := First (Expressions (Expr));
Index_Typ := First_Index (P_Type);
while Present (Index) and then Present (Index_Typ) loop
Analyze_And_Resolve (Index, Etype (Index_Typ));
Next (Index);
Next_Index (Index_Typ);
end loop;
-- Detect a case where the association either lacks an
-- index or contains an extra index.
if Present (Index) or else Present (Index_Typ) then
Error_Msg_N
("dimension mismatch in index list", Assoc);
end if;
end if;
Next (Expr);
end loop;
-- The current association denotes either a single component or a
-- range of components of a one dimensional array:
-- 1, 2 .. 5
-- Resolve the index or its high and low bounds (if range) against
-- the proper index type of the array.
else
Index := First (Choices (Assoc));
Index_Typ := First_Index (P_Type);
if Present (Next_Index (Index_Typ)) then
Error_Msg_N ("too few subscripts in array reference", Assoc);
end if;
while Present (Index) loop
-- The use of others is illegal (SPARK RM 4.4.1(12))
if Nkind (Index) = N_Others_Choice then
Error_Attr
("others choice not allowed in attribute %", Index);
-- The index denotes a range of elements
elsif Nkind (Index) = N_Range then
Low := Low_Bound (Index);
High := High_Bound (Index);
Analyze_And_Resolve (Low, Etype (Index_Typ));
Analyze_And_Resolve (High, Etype (Index_Typ));
-- Add a range check to ensure that the bounds of the
-- range are within the index type when this cannot be
-- determined statically.
if not Is_OK_Static_Expression (Low) then
Set_Do_Range_Check (Low);
end if;
if not Is_OK_Static_Expression (High) then
Set_Do_Range_Check (High);
end if;
-- Otherwise the index denotes a single element
else
Analyze_And_Resolve (Index, Etype (Index_Typ));
-- Add a range check to ensure that the index is within
-- the index type when it is not possible to determine
-- this statically.
if not Is_OK_Static_Expression (Index) then
Set_Do_Range_Check (Index);
end if;
end if;
Next (Index);
end loop;
end if;
end Analyze_Array_Component_Update;
-------------------------------------
-- Analyze_Record_Component_Update --
-------------------------------------
procedure Analyze_Record_Component_Update (Comp : Node_Id) is
Comp_Name : constant Name_Id := Chars (Comp);
Base_Typ : Entity_Id;
Comp_Or_Discr : Entity_Id;
begin
-- Find the discriminant or component whose name corresponds to
-- Comp. A simple character comparison is sufficient because all
-- visible names within a record type are unique.
Comp_Or_Discr := First_Entity (P_Type);
while Present (Comp_Or_Discr) loop
if Chars (Comp_Or_Discr) = Comp_Name then
-- Decorate the component reference by setting its entity
-- and type for resolution purposes.
Set_Entity (Comp, Comp_Or_Discr);
Set_Etype (Comp, Etype (Comp_Or_Discr));
exit;
end if;
Comp_Or_Discr := Next_Entity (Comp_Or_Discr);
end loop;
-- Diagnose an illegal reference
if Present (Comp_Or_Discr) then
if Ekind (Comp_Or_Discr) = E_Discriminant then
Error_Attr
("attribute % may not modify record discriminants", Comp);
else pragma Assert (Ekind (Comp_Or_Discr) = E_Component);
if Contains (Comps, Comp_Or_Discr) then
Error_Msg_N ("component & already updated", Comp);
-- Mark this component as processed
else
Append_New_Elmt (Comp_Or_Discr, Comps);
end if;
end if;
-- The update aggregate mentions an entity that does not belong to
-- the record type.
else
Error_Msg_N ("& is not a component of aggregate subtype", Comp);
end if;
-- Verify the consistency of types when the current component is
-- part of a miltiple component update.
-- Comp_1, ..., Comp_N => <value>
if Present (Etype (Comp)) then
Base_Typ := Base_Type (Etype (Comp));
-- Save the type of the first component reference as the
-- remaning references (if any) must resolve to this type.
if No (Common_Typ) then
Common_Typ := Base_Typ;
elsif Base_Typ /= Common_Typ then
Error_Msg_N
("components in choice list must have same type", Comp);
end if;
end if;
end Analyze_Record_Component_Update;
-- Local variables
Assoc : Node_Id;
Comp : Node_Id;
-- Start of processing for Update
begin
Check_E1;
if not Is_Object_Reference (P) then
Error_Attr_P ("prefix of attribute % must denote an object");
elsif not Is_Array_Type (P_Type)
and then not Is_Record_Type (P_Type)
then
Error_Attr_P ("prefix of attribute % must be a record or array");
elsif Is_Limited_View (P_Type) then
Error_Attr ("prefix of attribute % cannot be limited", N);
elsif Nkind (E1) /= N_Aggregate then
Error_Attr ("attribute % requires component association list", N);
end if;
-- Inspect the update aggregate, looking at all the associations and
-- choices. Perform the following checks:
-- 1) Legality of "others" in all cases
-- 2) Legality of <>
-- 3) Component legality for arrays
-- 4) Component legality for records
-- The remaining checks are performed on the expanded attribute
Assoc := First (Component_Associations (E1));
while Present (Assoc) loop
-- The use of <> is illegal (SPARK RM 4.4.1(1))
if Box_Present (Assoc) then
Error_Attr
("default initialization not allowed in attribute %", Assoc);
-- Otherwise process the association
else
Analyze (Expression (Assoc));
if Is_Array_Type (P_Type) then
Analyze_Array_Component_Update (Assoc);
elsif Is_Record_Type (P_Type) then
-- Reset the common type used in a multiple component update
-- as we are processing the contents of a new association.
Common_Typ := Empty;
Comp := First (Choices (Assoc));
while Present (Comp) loop
if Nkind (Comp) = N_Identifier then
Analyze_Record_Component_Update (Comp);
-- The use of others is illegal (SPARK RM 4.4.1(5))
elsif Nkind (Comp) = N_Others_Choice then
Error_Attr
("others choice not allowed in attribute %", Comp);
-- The name of a record component cannot appear in any
-- other form.
else
Error_Msg_N
("name should be identifier or OTHERS", Comp);
end if;
Next (Comp);
end loop;
end if;
end if;
Next (Assoc);
end loop;
-- The type of attribute 'Update is that of the prefix
Set_Etype (N, P_Type);
Sem_Warn.Warn_On_Suspicious_Update (N);
end Update;
---------
-- Val --
---------
when Attribute_Val =>
Check_E1;
Check_Discrete_Type;
if Is_Boolean_Type (P_Type) then
Error_Msg_Name_1 := Aname;
Error_Msg_Name_2 := Chars (P_Type);
Check_SPARK_05_Restriction
("attribute% is not allowed for type%", P);
end if;
-- 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.
Resolve (E1, Any_Integer);
Set_Etype (N, P_Base_Type);
-----------
-- 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_P ("object for % attribute must be of scalar type");
end if;
-- If the attribute appears within the subtype's own predicate
-- function, then issue a warning that this will cause infinite
-- recursion.
declare
Pred_Func : constant Entity_Id := Predicate_Function (P_Type);
begin
if Present (Pred_Func) and then Current_Scope = Pred_Func then
Error_Msg_N
("attribute Valid requires a predicate check??", N);
Error_Msg_N ("\and will result in infinite recursion??", N);
end if;
end;
Set_Etype (N, Standard_Boolean);
-------------------
-- Valid_Scalars --
-------------------
when Attribute_Valid_Scalars =>
Check_E0;
Check_Object_Reference (P);
Set_Etype (N, Standard_Boolean);
-- Following checks are only for source types
if Comes_From_Source (N) then
if not Scalar_Part_Present (P_Type) then
Error_Attr_P
("??attribute % always True, no scalars to check");
end if;
-- Not allowed for unchecked union type
if Has_Unchecked_Union (P_Type) then
Error_Attr_P
("attribute % not allowed for Unchecked_Union type");
end if;
end if;
-----------
-- Value --
-----------
when Attribute_Value =>
Check_SPARK_05_Restriction_On_Attribute;
Check_E1;
Check_Scalar_Type;
-- Case of enumeration type
-- When an enumeration type appears in an attribute reference, all
-- literals of the type are marked as referenced. This must only be
-- done if the attribute reference appears in the current source.
-- Otherwise the information on references may differ between a
-- normal compilation and one that performs inlining.
if Is_Enumeration_Type (P_Type)
and then In_Extended_Main_Code_Unit (N)
then
Check_Restriction (No_Enumeration_Maps, N);
-- Mark all enumeration literals as referenced, since the use of
-- the Value attribute can implicitly reference any of the
-- literals of the enumeration base type.
declare
Ent : Entity_Id := First_Literal (P_Base_Type);
begin
while Present (Ent) loop
Set_Referenced (Ent);
Next_Literal (Ent);
end loop;
end;
end if;
-- Set Etype before resolving expression because expansion of
-- expression may require enclosing type. Note that the type
-- returned by 'Value is the base type of the prefix type.
Set_Etype (N, P_Base_Type);
Validate_Non_Static_Attribute_Function_Call;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
----------------
-- 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 =>
Check_SPARK_05_Restriction_On_Attribute;
Check_Scalar_Type;
Set_Etype (N, Standard_Wide_String);
Check_E1;
Resolve (E1, P_Base_Type);
Validate_Non_Static_Attribute_Function_Call;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
---------------------
-- Wide_Wide_Image --
---------------------
when Attribute_Wide_Wide_Image =>
Check_Scalar_Type;
Set_Etype (N, Standard_Wide_Wide_String);
Check_E1;
Resolve (E1, P_Base_Type);
Validate_Non_Static_Attribute_Function_Call;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
----------------
-- Wide_Value --
----------------
when Attribute_Wide_Value =>
Check_SPARK_05_Restriction_On_Attribute;
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;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
---------------------
-- Wide_Wide_Value --
---------------------
when Attribute_Wide_Wide_Value =>
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;
-- Check restriction No_Fixed_IO
if Restriction_Check_Required (No_Fixed_IO)
and then Is_Fixed_Point_Type (P_Type)
then
Check_Restriction (No_Fixed_IO, P);
end if;
---------------------
-- Wide_Wide_Width --
---------------------
when Attribute_Wide_Wide_Width =>
Check_E0;
Check_Scalar_Type;
Set_Etype (N, Universal_Integer);
----------------
-- Wide_Width --
----------------
when Attribute_Wide_Width =>
Check_SPARK_05_Restriction_On_Attribute;
Check_E0;
Check_Scalar_Type;
Set_Etype (N, Universal_Integer);
-----------
-- Width --
-----------
when Attribute_Width =>
Check_SPARK_05_Restriction_On_Attribute;
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 (TSS_Stream_Write);
Set_Etype (N, Standard_Void_Type);
Resolve (N, Standard_Void_Type);
end case;
-- In SPARK certain attributes (see below) depend on Tasking_State.
-- Ensure that the entity is available for gnat2why by loading it.
-- See SPARK RM 9(18) for the relevant rule.
if GNATprove_Mode then
declare
Unused : Entity_Id;
begin
case Attr_Id is
when Attribute_Callable
| Attribute_Caller
| Attribute_Count
| Attribute_Terminated
=>
Unused := RTE (RE_Tasking_State);
when others =>
null;
end case;
end;
end if;
-- 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.
-- Note: we set the attribute analyzed in this case to prevent any
-- attempt at reanalysis which could generate spurious error msgs.
exception
when Bad_Attribute =>
Set_Analyzed (N);
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 the result is Static. This is set by the general processing
-- to true if the prefix is static, and all expressions are static. It
-- can be reset as processing continues for particular attributes. This
-- flag can still be True if the reference raises a constraint error.
-- Is_Static_Expression (N) is set to follow this value as it is set
-- and we could always reference this, but it is convenient to have a
-- simple short name to use, since it is frequently referenced.
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.
procedure Check_Concurrent_Discriminant (Bound : Node_Id);
-- If Bound is a reference to a discriminant of a task or protected type
-- occurring within the object's body, rewrite attribute reference into
-- a reference to the corresponding discriminal. Use for the expansion
-- of checks against bounds of entry family index subtypes.
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.
function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean;
-- Determines if the given type has compile time known bounds. Note
-- that we enter the case statement even in cases where the prefix
-- type does NOT have known bounds, so it is important to guard any
-- attempt to evaluate both bounds with a call to this function.
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.
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 Lo_Bound and Hi_Bound 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 and for First_Valid and Last_Valid.
-- Static is reset to False if the type or index type is not statically
-- constrained.
function Statically_Denotes_Entity (N : Node_Id) return Boolean;
-- Verify that the prefix of a potentially static array attribute
-- satisfies the conditions of 4.9 (14).
-----------------------------------
-- Check_Concurrent_Discriminant --
-----------------------------------
procedure Check_Concurrent_Discriminant (Bound : Node_Id) is
Tsk : Entity_Id;
-- The concurrent (task or protected) type
begin
if Nkind (Bound) = N_Identifier
and then Ekind (Entity (Bound)) = E_Discriminant
and then Is_Concurrent_Record_Type (Scope (Entity (Bound)))
then
Tsk := Corresponding_Concurrent_Type (Scope (Entity (Bound)));
if In_Open_Scopes (Tsk) and then Has_Completion (Tsk) then
-- Find discriminant of original concurrent type, and use
-- its current discriminal, which is the renaming within
-- the task/protected body.
Rewrite (N,
New_Occurrence_Of
(Find_Body_Discriminal (Entity (Bound)), Loc));
end if;
end if;
end Check_Concurrent_Discriminant;
-----------------------
-- Check_Expressions --
-----------------------
procedure Check_Expressions is
E : Node_Id;
begin
E := E1;
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, False);
-- Check that result is in bounds of the type if it is static
if Is_In_Range (N, T, Assume_Valid => False) then
null;
elsif Is_Out_Of_Range (N, T) then
Apply_Compile_Time_Constraint_Error
(N, "value not in range of}??", CE_Range_Check_Failed);
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;
-------------------------------
-- Compile_Time_Known_Bounds --
-------------------------------
function Compile_Time_Known_Bounds (Typ : Entity_Id) return Boolean is
begin
return
Compile_Time_Known_Value (Type_Low_Bound (Typ))
and then
Compile_Time_Known_Value (Type_High_Bound (Typ));
end Compile_Time_Known_Bounds;
----------------
-- 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
Ityp := Etype (First_Index (Base_Type (P_Type)));
Lo_Bound := Type_Low_Bound (Ityp);
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;
-- For a fixed-point type, we must freeze to get the attributes
-- of the fixed-point type set now so we can reference them.
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);
-- If subtype is non-static, result is definitely non-static
if not Is_Static_Subtype (Ityp) then
Static := False;
Set_Is_Static_Expression (N, False);
-- Subtype is static, does it raise CE?
elsif not Is_OK_Static_Subtype (Ityp) then
Set_Raises_Constraint_Error (N);
end if;
end Set_Bounds;
-------------------------------
-- Statically_Denotes_Entity --
-------------------------------
function Statically_Denotes_Entity (N : Node_Id) return Boolean is
E : Entity_Id;
begin
if not Is_Entity_Name (N) then
return False;
else
E := Entity (N);
end if;
return
Nkind (Parent (E)) /= N_Object_Renaming_Declaration
or else Statically_Denotes_Entity (Renamed_Object (E));
end Statically_Denotes_Entity;
-- Start of processing for Eval_Attribute
begin
-- Initialize result as non-static, will be reset if appropriate
Set_Is_Static_Expression (N, False);
Static := False;
-- 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 Enabled attribute. This attribute has a very
-- special prefix, and the easiest way to avoid lots of special checks
-- to protect this special prefix from causing trouble is to deal with
-- this attribute immediately and be done with it.
if Id = Attribute_Enabled then
-- We skip evaluation if the expander is not active. This is not just
-- an optimization. It is of key importance that we not rewrite the
-- attribute in a generic template, since we want to pick up the
-- setting of the check in the instance, Testing Expander_Active
-- might seem an easy way of doing this, but we need to account for
-- ASIS needs, so check explicitly for a generic context.
if not Inside_A_Generic then
declare
C : constant Check_Id := Get_Check_Id (Chars (P));
R : Boolean;
begin
if No (E1) then
if C in Predefined_Check_Id then
R := Scope_Suppress.Suppress (C);
else
R := Is_Check_Suppressed (Empty, C);
end if;
else
R := Is_Check_Suppressed (Entity (E1), C);
end if;
Rewrite (N, New_Occurrence_Of (Boolean_Literals (not R), Loc));
end;
end if;
return;
end if;
-- Attribute 'Img applied to a static enumeration value is static, and
-- we will do the folding right here (things get confused if we let this
-- case go through the normal circuitry).
if Attribute_Name (N) = Name_Img
and then Is_Entity_Name (P)
and then Is_Enumeration_Type (Etype (Entity (P)))
and then Is_OK_Static_Expression (P)
then
declare
Lit : constant Entity_Id := Expr_Value_E (P);
Str : String_Id;
begin
Start_String;
Get_Unqualified_Decoded_Name_String (Chars (Lit));
Set_Casing (All_Upper_Case);
Store_String_Chars (Name_Buffer (1 .. Name_Len));
Str := End_String;
Rewrite (N, Make_String_Literal (Loc, Strval => Str));
Analyze_And_Resolve (N, Standard_String);
Set_Is_Static_Expression (N, True);
end;
return;
end if;
-- Special processing for cases where the prefix is an object. For this
-- purpose, a string literal counts as an object (attributes of string
-- literals can only appear in generated code).
if Is_Object_Reference (P) or else Nkind (P) = N_String_Literal 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 Enum_Rep, evaluation depends on the nature of the prefix and
-- the optional argument.
elsif Id = Attribute_Enum_Rep then
if Is_Entity_Name (P) then
declare
Enum_Expr : Node_Id;
-- The enumeration-type expression of interest
begin
-- P'Enum_Rep case
if Ekind_In (Entity (P), E_Constant,
E_Enumeration_Literal)
then
Enum_Expr := P;
-- Enum_Type'Enum_Rep (E1) case
elsif Is_Enumeration_Type (Entity (P)) then
Enum_Expr := E1;
-- Otherwise the attribute must be expanded into a
-- conversion and evaluated at run time.
else
Check_Expressions;
return;
end if;
-- We can fold if the expression is an enumeration
-- literal, or if it denotes a constant whose value
-- is known at compile time.
if Nkind (Enum_Expr) in N_Has_Entity
and then (Ekind (Entity (Enum_Expr)) =
E_Enumeration_Literal
or else
(Ekind (Entity (Enum_Expr)) = E_Constant
and then Nkind (Parent (Entity (Enum_Expr))) =
N_Object_Declaration
and then Compile_Time_Known_Value
(Expression (Parent (Entity (P))))))
then
P_Entity := Etype (P);
else
Check_Expressions;
return;
end if;
end;
-- Otherwise the attribute is illegal, do not attempt to perform
-- any kind of folding.
else
return;
end if;
-- 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) and then Is_Constrained (AS) then
P_Entity := AS;
-- If we have an unconstrained type we 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)), Static);
return;
else
Check_Expressions;
return;
end if;
-- For Lock_Free, we apply the attribute to the type of the object.
-- This is allowed since we have already verified that the type is a
-- protected type.
elsif Id = Attribute_Lock_Free then
P_Entity := Etype (P);
-- 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;
-- If we are asked to evaluate an attribute where the prefix is a
-- non-frozen generic actual type whose RM_Size is still set to zero,
-- then abandon the effort.
if Is_Type (P_Entity)
and then (not Is_Frozen (P_Entity)
and then Is_Generic_Actual_Type (P_Entity)
and then RM_Size (P_Entity) = 0)
-- However, the attribute Unconstrained_Array must be evaluated,
-- since it is documented to be a static attribute (and can for
-- example appear in a Compile_Time_Warning pragma). The frozen
-- status of the type does not affect its evaluation.
and then Id /= Attribute_Unconstrained_Array
then
return;
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.
-- Here is where we make sure that static attributes are properly
-- marked as such. These are attributes whose prefix is a static
-- scalar subtype, whose result is scalar, and whose arguments, if
-- present, are static scalar expressions. Note that such references
-- are static expressions even if they raise Constraint_Error.
-- For example, Boolean'Pos (1/0 = 0) is a static expression, even
-- though evaluating it raises constraint error. This means that a
-- declaration like:
-- X : constant := (if True then 1 else Boolean'Pos (1/0 = 0));
-- is legal, since here this expression appears in a statically
-- unevaluated position, so it does not actually raise an exception.
if Is_Scalar_Type (P_Entity)
and then (not Is_Generic_Type (P_Entity))
and then Is_Static_Subtype (P_Entity)
and then Is_Scalar_Type (Etype (N))
and then
(No (E1)
or else (Is_Static_Expression (E1)
and then Is_Scalar_Type (Etype (E1))))
and then
(No (E2)
or else (Is_Static_Expression (E2)
and then Is_Scalar_Type (Etype (E1))))
then
Static := True;
Set_Is_Static_Expression (N, True);
end if;
-- 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_In (P_Entity, E_Variable, 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, there is no expression 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 Atomic_Always_Lock_Free, Has_Discriminants,
-- Lock_Free, Type_Class, Has_Tagged_Value, and Unconstrained_Array.
elsif (Id = Attribute_Atomic_Always_Lock_Free or else
Id = Attribute_Definite or else
Id = Attribute_Has_Access_Values or else
Id = Attribute_Has_Discriminants or else
Id = Attribute_Has_Tagged_Values or else
Id = Attribute_Lock_Free or else
Id = Attribute_Type_Class or else
Id = Attribute_Unconstrained_Array or else
Id = Attribute_Max_Alignment_For_Allocation)
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;
-- We can fold 'Alignment applied to a type if the alignment is known
-- (as happens for an alignment 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_Alignment
and then Is_Type (P_Entity)
and then (not Is_Generic_Type (P_Entity))
and then Known_Alignment (P_Entity)
then
Compile_Time_Known_Attribute (N, Alignment (P_Entity));
return;
-- If this is an access attribute that is known to fail accessibility
-- check, rewrite accordingly.
elsif Attribute_Name (N) = Name_Access
and then Raises_Constraint_Error (N)
then
Rewrite (N,
Make_Raise_Program_Error (Loc,
Reason => PE_Accessibility_Check_Failed));
Set_Etype (N, C_Type);
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 ones 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
if not Is_Static_Subtype (P_Type) then
Static := False;
Set_Is_Static_Expression (N, False);
elsif not Is_OK_Static_Subtype (P_Type) then
Set_Raises_Constraint_Error (N);
end if;
-- 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.
-- Atomic_Always_Lock_Free, Definite, Has_Access_Values,
-- Has_Discriminants, Has_Tagged_Values, Lock_Free, Type_Class, and
-- Unconstrained_Array are again exceptions, because they apply as well
-- to unconstrained types.
-- In addition Component_Size is an exception since it is possibly
-- foldable, even though it is never static, and it does apply to
-- unconstrained arrays. Furthermore, it is essential to fold this
-- in the packed case, since otherwise the value will be incorrect.
elsif Id = Attribute_Atomic_Always_Lock_Free or else
Id = Attribute_Definite or else
Id = Attribute_Has_Access_Values or else
Id = Attribute_Has_Discriminants or else
Id = Attribute_Has_Tagged_Values or else
Id = Attribute_Lock_Free or else
Id = Attribute_Type_Class or else
Id = Attribute_Unconstrained_Array or else
Id = Attribute_Component_Size
then
Static := False;
Set_Is_Static_Expression (N, False);
elsif Id /= Attribute_Max_Alignment_For_Allocation then
if not Is_Constrained (P_Type)
or else (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
-- an 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).
-- We also need to set Static properly for subsequent legality checks
-- which might otherwise accept non-static constants in contexts
-- where they are not legal.
Static :=
Ada_Version >= Ada_95 and then Statically_Denotes_Entity (P);
Set_Is_Static_Expression (N, Static);
declare
Nod : Node_Id;
begin
Nod := First_Index (P_Type);
-- The expression is static if the array type is constrained
-- by given bounds, and not by an initial expression. Constant
-- strings are static in any case.
if Root_Type (P_Type) /= Standard_String then
Static :=
Static and then not Is_Constr_Subt_For_U_Nominal (P_Type);
Set_Is_Static_Expression (N, Static);
end if;
while Present (Nod) loop
if not Is_Static_Subtype (Etype (Nod)) then
Static := False;
Set_Is_Static_Expression (N, False);
elsif not Is_OK_Static_Subtype (Etype (Nod)) then
Set_Raises_Constraint_Error (N);
Static := False;
Set_Is_Static_Expression (N, False);
end if;
-- If however the index type is generic, or derived from
-- one, attributes cannot be folded.
if Is_Generic_Type (Root_Type (Etype (Nod)))
and then Id /= Attribute_Component_Size
then
return;
end if;
Next_Index (Nod);
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
-- result certainly cannot be static.
if not Is_Static_Expression (E) then
Static := False;
Set_Is_Static_Expression (N, False);
end if;
if Raises_Constraint_Error (E) then
Set_Raises_Constraint_Error (N);
end if;
-- If the result is not known at compile time, or is not of
-- a scalar type, then the result is definitely not static,
-- so we can quit now.
if not Compile_Time_Known_Value (E)
or else not Is_Scalar_Type (Etype (E))
then
-- An odd special case, if this is a Pos attribute, this
-- is where we need to apply a range check since it does
-- not get done anywhere else.
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
Set_Is_Static_Expression (N, False);
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),
Reason => CE_Range_Check_Failed);
Set_Etype (CE_Node, Etype (N));
Set_Raises_Constraint_Error (CE_Node);
Check_Expressions;
Rewrite (N, Relocate_Node (CE_Node));
Set_Raises_Constraint_Error (N, True);
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.
-- In the case where Static is not set, we do know that all the
-- expressions present are at least known at compile time (we assumed
-- above that if this was not the case, then there was no hope of static
-- evaluation). However, we did not require that the bounds of the
-- prefix type be compile time known, let alone static). That's because
-- there are many attributes that can be computed at compile time on
-- non-static subtypes, even though such references are not static
-- expressions.
-- For VAX float, the root type is an IEEE type. So make sure to use the
-- base type instead of the root-type for floating point attributes.
case Id is
-- Attributes related to Ada 2012 iterators (placeholder ???)
when Attribute_Constant_Indexing
| Attribute_Default_Iterator
| Attribute_Implicit_Dereference
| Attribute_Iterator_Element
| Attribute_Iterable
| Attribute_Variable_Indexing
=>
null;
-- Internal attributes used to deal with Ada 2012 delayed aspects.
-- These were already rejected by the parser. Thus they shouldn't
-- appear here.
when Internal_Attribute_Id =>
raise Program_Error;
--------------
-- Adjacent --
--------------
when Attribute_Adjacent =>
Fold_Ureal
(N,
Eval_Fat.Adjacent
(P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
Static);
---------
-- Aft --
---------
when Attribute_Aft =>
Fold_Uint (N, Aft_Value (P_Type), Static);
---------------
-- 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), Static);
end if;
end Alignment_Block;
-----------------------------
-- Atomic_Always_Lock_Free --
-----------------------------
-- Atomic_Always_Lock_Free attribute is a Boolean, thus no need to fold
-- here.
when Attribute_Atomic_Always_Lock_Free => Atomic_Always_Lock_Free :
declare
V : constant Entity_Id :=
Boolean_Literals
(Support_Atomic_Primitives_On_Target
and then Support_Atomic_Primitives (P_Type));
begin
Rewrite (N, New_Occurrence_Of (V, Loc));
-- Analyze and resolve as boolean. Note that this attribute is a
-- static attribute in GNAT.
Analyze_And_Resolve (N, Standard_Boolean);
Static := True;
Set_Is_Static_Expression (N, True);
end Atomic_Always_Lock_Free;
---------
-- 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 =>
Fold_Ureal
(N, Eval_Fat.Ceiling (P_Base_Type, Expr_Value_R (E1)), Static);
--------------------
-- Component_Size --
--------------------
when Attribute_Component_Size =>
if Known_Static_Component_Size (P_Type) then
Fold_Uint (N, Component_Size (P_Type), Static);
end if;
-------------
-- Compose --
-------------
when Attribute_Compose =>
Fold_Ureal
(N,
Eval_Fat.Compose (P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
Static);
-----------------
-- 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 =>
-- The expander might fold it and set the static flag accordingly,
-- but with expansion disabled (as in ASIS), it remains as an
-- attribute reference, and this reference is not static.
Set_Is_Static_Expression (N, False);
null;
---------------
-- Copy_Sign --
---------------
when Attribute_Copy_Sign =>
Fold_Ureal
(N,
Eval_Fat.Copy_Sign
(P_Base_Type, Expr_Value_R (E1), Expr_Value_R (E2)),
Static);
--------------
-- Definite --
--------------
when Attribute_Definite =>
Rewrite (N, New_Occurrence_Of (
Boolean_Literals (Is_Definite_Subtype (P_Entity)), Loc));
Analyze_And_Resolve (N, Standard_Boolean);
-----------
-- Delta --
-----------
when Attribute_Delta =>
Fold_Ureal (N, Delta_Value (P_Type), True);
------------
-- Denorm --
------------
when Attribute_Denorm =>
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Has_Denormals (P_Type))), Static);
---------------------
-- Descriptor_Size --
---------------------
when Attribute_Descriptor_Size =>
null;
------------
-- Digits --
------------
when Attribute_Digits =>
Fold_Uint (N, Digits_Value (P_Type), Static);
----------
-- Emax --
----------
when Attribute_Emax =>
-- Ada 83 attribute is defined as (RM83 3.5.8)
-- T'Emax = 4 * T'Mantissa
Fold_Uint (N, 4 * Mantissa, Static);
--------------
-- Enum_Rep --
--------------
when Attribute_Enum_Rep => Enum_Rep : declare
Val : Node_Id;
begin
-- The attribute appears in the form:
-- Enum_Typ'Enum_Rep (Const)
-- Enum_Typ'Enum_Rep (Enum_Lit)
if Present (E1) then
Val := E1;
-- Otherwise the prefix denotes a constant or enumeration literal:
-- Const'Enum_Rep
-- Enum_Lit'Enum_Rep
else
Val := P;
end if;
-- For an enumeration type with a non-standard representation use
-- the Enumeration_Rep field of the proper constant. Note that this
-- will not work for types Character/Wide_[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 (Val)), Static);
-- 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 (Val), Static);
end if;
end Enum_Rep;
--------------
-- Enum_Val --
--------------
when Attribute_Enum_Val => Enum_Val : declare
Lit : Node_Id;
begin
-- We have something like Enum_Type'Enum_Val (23), so search for a
-- corresponding value in the list of Enum_Rep values for the type.
Lit := First_Literal (P_Base_Type);
loop
if Enumeration_Rep (Lit) = Expr_Value (E1) then
Fold_Uint (N, Enumeration_Pos (Lit), Static);
exit;
end if;
Next_Literal (Lit);
if No (Lit) then
Apply_Compile_Time_Constraint_Error
(N, "no representation value matches",
CE_Range_Check_Failed,
Warn => not Static);
exit;
end if;
end loop;
end Enum_Val;
-------------
-- 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), True);
--------------
-- Exponent --
--------------
when Attribute_Exponent =>
Fold_Uint (N,
Eval_Fat.Exponent (P_Base_Type, Expr_Value_R (E1)), Static);
-----------------------
-- Finalization_Size --
-----------------------
when Attribute_Finalization_Size =>
null;
-----------
-- First --
-----------
when Attribute_First =>
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), Static);
else
Fold_Uint (N, Expr_Value (Lo_Bound), Static);
end if;
else
Check_Concurrent_Discriminant (Lo_Bound);
end if;
-----------------
-- First_Valid --
-----------------
when Attribute_First_Valid =>
if Has_Predicates (P_Type)
and then Has_Static_Predicate (P_Type)
then
declare
FirstN : constant Node_Id :=
First (Static_Discrete_Predicate (P_Type));
begin
if Nkind (FirstN) = N_Range then
Fold_Uint (N, Expr_Value (Low_Bound (FirstN)), Static);
else
Fold_Uint (N, Expr_Value (FirstN), Static);
end if;
end;
else
Set_Bounds;
Fold_Uint (N, Expr_Value (Lo_Bound), Static);
end if;
-----------------
-- Fixed_Value --
-----------------
when Attribute_Fixed_Value =>
null;
-----------
-- Floor --
-----------
when Attribute_Floor =>
Fold_Ureal
(N, Eval_Fat.Floor (P_Base_Type, Expr_Value_R (E1)), Static);
----------
-- Fore --
----------
when Attribute_Fore =>
if Compile_Time_Known_Bounds (P_Type) then
Fold_Uint (N, UI_From_Int (Fore_Value), Static);
end if;
--------------
-- Fraction --
--------------
when Attribute_Fraction =>
Fold_Ureal
(N, Eval_Fat.Fraction (P_Base_Type, Expr_Value_R (E1)), Static);
-----------------------
-- Has_Access_Values --
-----------------------
when Attribute_Has_Access_Values =>
Rewrite (N, New_Occurrence_Of
(Boolean_Literals (Has_Access_Values (P_Root_Type)), Loc));
Analyze_And_Resolve (N, Standard_Boolean);
-----------------------
-- Has_Discriminants --
-----------------------
when Attribute_Has_Discriminants =>
Rewrite (N, New_Occurrence_Of (
Boolean_Literals (Has_Discriminants (P_Entity)), Loc));
Analyze_And_Resolve (N, Standard_Boolean);
----------------------
-- Has_Same_Storage --
----------------------
when Attribute_Has_Same_Storage =>
null;
-----------------------
-- Has_Tagged_Values --
-----------------------
when Attribute_Has_Tagged_Values =>
Rewrite (N, New_Occurrence_Of
(Boolean_Literals (Has_Tagged_Component (P_Root_Type)), Loc));
Analyze_And_Resolve (N, Standard_Boolean);
--------------
-- 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))
-- However, we can constant-fold the image of an enumeration literal
-- if names are available.
when Attribute_Image =>
if Is_Entity_Name (E1)
and then Ekind (Entity (E1)) = E_Enumeration_Literal
and then not Discard_Names (First_Subtype (Etype (E1)))
and then not Global_Discard_Names
then
declare
Lit : constant Entity_Id := Entity (E1);
Str : String_Id;
begin
Start_String;
Get_Unqualified_Decoded_Name_String (Chars (Lit));
Set_Casing (All_Upper_Case);
Store_String_Chars (Name_Buffer (1 .. Name_Len));
Str := End_String;
Rewrite (N, Make_String_Literal (Loc, Strval => Str));
Analyze_And_Resolve (N, Standard_String);
Set_Is_Static_Expression (N, False);
end;
end if;
-------------------
-- Integer_Value --
-------------------
-- We never try to fold Integer_Value (though perhaps we could???)
when Attribute_Integer_Value =>
null;
-------------------
-- Invalid_Value --
-------------------
-- Invalid_Value is a scalar attribute that is never static, because
-- the value is by design out of range.
when Attribute_Invalid_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)),
True);
end if;
---------------
-- Lock_Free --
---------------
when Attribute_Lock_Free => Lock_Free : declare
V : constant Entity_Id := Boolean_Literals (Uses_Lock_Free (P_Type));
begin
Rewrite (N, New_Occurrence_Of (V, Loc));
-- Analyze and resolve as boolean. Note that this attribute is a
-- static attribute in GNAT.
Analyze_And_Resolve (N, Standard_Boolean);
Static := True;
Set_Is_Static_Expression (N, True);
end Lock_Free;
----------
-- Last --
----------
when Attribute_Last =>
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), Static);
else
Fold_Uint (N, Expr_Value (Hi_Bound), Static);
end if;
else
Check_Concurrent_Discriminant (Hi_Bound);
end if;
----------------
-- Last_Valid --
----------------
when Attribute_Last_Valid =>
if Has_Predicates (P_Type)
and then Has_Static_Predicate (P_Type)
then
declare
LastN : constant Node_Id :=
Last (Static_Discrete_Predicate (P_Type));
begin
if Nkind (LastN) = N_Range then
Fold_Uint (N, Expr_Value (High_Bound (LastN)), Static);
else
Fold_Uint (N, Expr_Value (LastN), Static);
end if;
end;
else
Set_Bounds;
Fold_Uint (N, Expr_Value (Hi_Bound), Static);
end if;
------------------
-- Leading_Part --
------------------
when Attribute_Leading_Part =>
Fold_Ureal
(N,
Eval_Fat.Leading_Part
(P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
Static);
------------
-- Length --
------------
when Attribute_Length => Length : declare
Ind : Node_Id;
begin
-- If any index type is a formal type, or derived from one, the
-- bounds are not static. Treating them as static can produce
-- spurious warnings or improper constant folding.
Ind := First_Index (P_Type);
while Present (Ind) loop
if Is_Generic_Type (Root_Type (Etype (Ind))) then
return;
end if;
Next_Index (Ind);
end loop;
Set_Bounds;
-- For two compile time values, we can compute length
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))),
Static);
end if;
-- One more case is where Hi_Bound and Lo_Bound are compile-time
-- comparable, and we can figure out the difference between them.
declare
Diff : aliased Uint;
begin
case
Compile_Time_Compare
(Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
is
when EQ =>
Fold_Uint (N, Uint_1, Static);
when GT =>
Fold_Uint (N, Uint_0, Static);
when LT =>
if Diff /= No_Uint then
Fold_Uint (N, Diff + 1, Static);
end if;
when others =>
null;
end case;
end;
end Length;
----------------
-- Loop_Entry --
----------------
-- Loop_Entry acts as an alias of a constant initialized to the prefix
-- of the said attribute at the point of entry into the related loop. As
-- such, the attribute reference does not need to be evaluated because
-- the prefix is the one that is evaluted.
when Attribute_Loop_Entry =>
null;
-------------
-- Machine --
-------------
when Attribute_Machine =>
Fold_Ureal
(N,
Eval_Fat.Machine
(P_Base_Type, Expr_Value_R (E1), Eval_Fat.Round, N),
Static);
------------------
-- Machine_Emax --
------------------
when Attribute_Machine_Emax =>
Fold_Uint (N, Machine_Emax_Value (P_Type), Static);
------------------
-- Machine_Emin --
------------------
when Attribute_Machine_Emin =>
Fold_Uint (N, Machine_Emin_Value (P_Type), Static);
----------------------
-- Machine_Mantissa --
----------------------
when Attribute_Machine_Mantissa =>
Fold_Uint (N, Machine_Mantissa_Value (P_Type), Static);
-----------------------
-- Machine_Overflows --
-----------------------
when Attribute_Machine_Overflows =>
-- Always true for fixed-point
if Is_Fixed_Point_Type (P_Type) then
Fold_Uint (N, True_Value, Static);
-- Floating point case
else
Fold_Uint (N,
UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
Static);
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, Static);
else
Fold_Uint (N, Uint_2, Static);
end if;
-- All floating-point type always have radix 2
else
Fold_Uint (N, Uint_2, Static);
end if;
----------------------
-- Machine_Rounding --
----------------------
-- Note: for the folding case, it is fine to treat Machine_Rounding
-- exactly the same way as Rounding, since this is one of the allowed
-- behaviors, and performance is not an issue here. It might be a bit
-- better to give the same result as it would give at run time, even
-- though the non-determinism is certainly permitted.
when Attribute_Machine_Rounding =>
Fold_Ureal
(N, Eval_Fat.Rounding (P_Base_Type, Expr_Value_R (E1)), Static);
--------------------
-- Machine_Rounds --
--------------------
when Attribute_Machine_Rounds =>
-- Always False for fixed-point
if Is_Fixed_Point_Type (P_Type) then
Fold_Uint (N, False_Value, Static);
-- Else yield proper floating-point result
else
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)),
Static);
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), Static);
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, Static);
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, Static);
end if;
---------
-- Max --
---------
when Attribute_Max =>
if Is_Real_Type (P_Type) then
Fold_Ureal
(N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
else
Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
end if;
----------------------------------
-- Max_Alignment_For_Allocation --
----------------------------------
-- Max_Alignment_For_Allocation is usually the Alignment. However,
-- arrays are allocated with dope, so we need to take into account both
-- the alignment of the array, which comes from the component alignment,
-- and the alignment of the dope. Also, if the alignment is unknown, we
-- use the max (it's OK to be pessimistic).
when Attribute_Max_Alignment_For_Allocation => Max_Align : declare
A : Uint := UI_From_Int (Ttypes.Maximum_Alignment);
begin
if Known_Alignment (P_Type)
and then (not Is_Array_Type (P_Type) or else Alignment (P_Type) > A)
then
A := Alignment (P_Type);
end if;
Fold_Uint (N, A, Static);
end Max_Align;
----------------------------------
-- 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,
Static);
end if;
--------------------
-- Mechanism_Code --
--------------------
when Attribute_Mechanism_Code => Mechanism_Code : declare
Formal : Entity_Id;
Mech : Mechanism_Type;
Val : Int;
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)), Static);
end if;
end Mechanism_Code;
---------
-- Min --
---------
when Attribute_Min =>
if Is_Real_Type (P_Type) then
Fold_Ureal
(N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
else
Fold_Uint
(N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
end if;
---------
-- Mod --
---------
when Attribute_Mod =>
Fold_Uint
(N, UI_Mod (Expr_Value (E1), Modulus (P_Base_Type)), Static);
-----------
-- Model --
-----------
when Attribute_Model =>
Fold_Ureal
(N, Eval_Fat.Model (P_Base_Type, Expr_Value_R (E1)), Static);
----------------
-- Model_Emin --
----------------
when Attribute_Model_Emin =>
Fold_Uint (N, Model_Emin_Value (P_Base_Type), Static);
-------------------
-- Model_Epsilon --
-------------------
when Attribute_Model_Epsilon =>
Fold_Ureal (N, Model_Epsilon_Value (P_Base_Type), Static);
--------------------
-- Model_Mantissa --
--------------------
when Attribute_Model_Mantissa =>
Fold_Uint (N, Model_Mantissa_Value (P_Base_Type), Static);
-----------------
-- Model_Small --
-----------------
when Attribute_Model_Small =>
Fold_Ureal (N, Model_Small_Value (P_Base_Type), Static);
-------------
-- Modulus --
-------------
when Attribute_Modulus =>
Fold_Uint (N, Modulus (P_Type), Static);
--------------------
-- 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), Static);
end if;
end Object_Size;
----------------------
-- Overlaps_Storage --
----------------------
when Attribute_Overlaps_Storage =>
null;
-------------------------
-- Passed_By_Reference --
-------------------------
-- Scalar types are never passed by reference
when Attribute_Passed_By_Reference =>
Fold_Uint (N, False_Value, Static);
---------
-- Pos --
---------
when Attribute_Pos =>
Fold_Uint (N, Expr_Value (E1), Static);
----------
-- Pred --
----------
when Attribute_Pred =>
-- Floating-point case
if Is_Floating_Point_Type (P_Type) then
Fold_Ureal
(N, Eval_Fat.Pred (P_Base_Type, Expr_Value_R (E1)), Static);
-- Fixed-point case
elsif Is_Fixed_Point_Type (P_Type) then
Fold_Ureal
(N, Expr_Value_R (E1) - Small_Value (P_Type), True);
-- Modular integer case (wraps)
elsif Is_Modular_Integer_Type (P_Type) then
Fold_Uint (N, (Expr_Value (E1) - 1) mod Modulus (P_Type), Static);
-- 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 `&''First`",
CE_Overflow_Check_Failed,
Ent => P_Base_Type,
Warn => not Static);
Check_Expressions;
return;
end if;
Fold_Uint (N, Expr_Value (E1) - 1, Static);
end if;
-----------
-- 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 => Range_Length : declare
Diff : aliased Uint;
begin
Set_Bounds;
-- Can fold if both bounds are compile time known
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),
Static);
end if;
-- One more case is where Hi_Bound and Lo_Bound are compile-time
-- comparable, and we can figure out the difference between them.
case Compile_Time_Compare
(Lo_Bound, Hi_Bound, Diff'Access, Assume_Valid => False)
is
when EQ =>
Fold_Uint (N, Uint_1, Static);
when GT =>
Fold_Uint (N, Uint_0, Static);
when LT =>
if Diff /= No_Uint then
Fold_Uint (N, Diff + 1, Static);
end if;
when others =>
null;
end case;
end Range_Length;
---------
-- Ref --
---------
when Attribute_Ref =>
Fold_Uint (N, Expr_Value (E1), Static);
---------------
-- Remainder --
---------------
when Attribute_Remainder => Remainder : declare
X : constant Ureal := Expr_Value_R (E1);
Y : constant Ureal := Expr_Value_R (E2);
begin
if UR_Is_Zero (Y) then
Apply_Compile_Time_Constraint_Error
(N, "division by zero in Remainder",
CE_Overflow_Check_Failed,
Warn => not Static);
Check_Expressions;
return;
end if;
Fold_Ureal (N, Eval_Fat.Remainder (P_Base_Type, X, Y), Static);
end Remainder;
-----------------
-- Restriction --
-----------------
when Attribute_Restriction_Set =>
Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
Set_Is_Static_Expression (N);
-----------
-- Round --
-----------
when Attribute_Round => Round : declare
Sr : Ureal;
Si : Uint;
begin
-- 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), Static);
end Round;
--------------
-- Rounding --
--------------
when Attribute_Rounding =>
Fold_Ureal
(N, Eval_Fat.Rounding (P_Base_Type, Expr_Value_R (E1)), Static);
---------------
-- Safe_Emax --
---------------
when Attribute_Safe_Emax =>
Fold_Uint (N, Safe_Emax_Value (P_Type), Static);
----------------
-- Safe_First --
----------------
when Attribute_Safe_First =>
Fold_Ureal (N, Safe_First_Value (P_Type), Static);
----------------
-- 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)), Static);
else
Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
end if;
---------------
-- Safe_Last --
---------------
when Attribute_Safe_Last =>
Fold_Ureal (N, Safe_Last_Value (P_Type), Static);
----------------
-- 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), Static);
-- Ada 83 Safe_Small for floating-point cases
else
Fold_Ureal (N, Model_Small_Value (P_Type), Static);
end if;
-----------
-- Scale --
-----------
when Attribute_Scale =>
Fold_Uint (N, Scale_Value (P_Type), Static);
-------------
-- Scaling --
-------------
when Attribute_Scaling =>
Fold_Ureal
(N,
Eval_Fat.Scaling
(P_Base_Type, Expr_Value_R (E1), Expr_Value (E2)),
Static);
------------------
-- Signed_Zeros --
------------------
when Attribute_Signed_Zeros =>
Fold_Uint
(N, UI_From_Int (Boolean'Pos (Has_Signed_Zeros (P_Type))), Static);
----------
-- 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. This is
-- one of the places where it is annoying that a size of zero means two
-- things (zero size for scalars, unspecified size for non-scalars).
when Attribute_Size
| Attribute_VADS_Size
=>
Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if Is_Scalar_Type (P_TypeA)
or else 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)), Static);
-- 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), Static);
end if;
end;
-- Normal case (Size) in which case we want the RM_Size
else
Fold_Uint (N, RM_Size (P_TypeA), Static);
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), Static);
-- Normal Ada 95 fixed-point case
else
Fold_Ureal (N, Small_Value (P_Type), True);
end if;
-----------------
-- Stream_Size --
-----------------
when Attribute_Stream_Size =>
null;
----------
-- Succ --
----------
when Attribute_Succ =>
-- Floating-point case
if Is_Floating_Point_Type (P_Type) then
Fold_Ureal
(N, Eval_Fat.Succ (P_Base_Type, Expr_Value_R (E1)), Static);
-- Fixed-point case
elsif Is_Fixed_Point_Type (P_Type) then
Fold_Ureal (N, Expr_Value_R (E1) + Small_Value (P_Type), Static);
-- Modular integer case (wraps)
elsif Is_Modular_Integer_Type (P_Type) then
Fold_Uint (N, (Expr_Value (E1) + 1) mod Modulus (P_Type), Static);
-- 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 `&''Last`",
CE_Overflow_Check_Failed,
Ent => P_Base_Type,
Warn => not Static);
Check_Expressions;
return;
else
Fold_Uint (N, Expr_Value (E1) + 1, Static);
end if;
end if;
----------------
-- Truncation --
----------------
when Attribute_Truncation =>
Fold_Ureal
(N,
Eval_Fat.Truncation (P_Base_Type, Expr_Value_R (E1)),
Static);
----------------
-- Type_Class --
----------------
when Attribute_Type_Class => Type_Class : declare
Typ : constant Entity_Id := Underlying_Type (P_Base_Type);
Id : RE_Id;
begin
if Is_Descendant_Of_Address (Typ) 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_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_Class 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 =>
Fold_Ureal
(N,
Eval_Fat.Unbiased_Rounding (P_Base_Type, Expr_Value_R (E1)),
Static);
-------------------------
-- Unconstrained_Array --
-------------------------
when Attribute_Unconstrained_Array => Unconstrained_Array : declare
Typ : constant Entity_Id := Underlying_Type (P_Type);
begin
Rewrite (N, New_Occurrence_Of (
Boolean_Literals (
Is_Array_Type (P_Type)
and then not Is_Constrained (Typ)), Loc));
-- Analyze and resolve as boolean, note that this attribute is
-- a static attribute in GNAT.
Analyze_And_Resolve (N, Standard_Boolean);
Static := True;
Set_Is_Static_Expression (N, True);
end Unconstrained_Array;
-- Attribute Update is never static
when Attribute_Update =>
return;
---------------
-- VADS_Size --
---------------
-- Processing is shared with Size
---------
-- Val --
---------
when Attribute_Val =>
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",
CE_Range_Check_Failed,
Warn => not Static);
Check_Expressions;
return;
else
Fold_Uint (N, Expr_Value (E1), Static);
end if;
----------------
-- 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. This is one of the places where
-- it is annoying that a size of zero means two things!
when Attribute_Value_Size => Value_Size : declare
P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
begin
if Is_Scalar_Type (P_TypeA) or else RM_Size (P_TypeA) /= Uint_0 then
Fold_Uint (N, RM_Size (P_TypeA), Static);
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_Wide_Image --
---------------------
-- Wide_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_Wide_Image =>
null;
---------------------
-- Wide_Wide_Width --
---------------------
-- Processing for Wide_Wide_Width is combined with Width
----------------
-- Wide_Width --
----------------
-- Processing for Wide_Width is combined with Width
-----------
-- Width --
-----------
-- This processing also handles the case of Wide_[Wide_]Width
when Attribute_Width
| Attribute_Wide_Width
| Attribute_Wide_Wide_Width
=>
if Compile_Time_Known_Bounds (P_Type) 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, Static);
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.
-- For machines where Long_Long_Float is the IEEE
-- extended precision type, the exponent takes 4 digits.
declare
Len : Int :=
Int'Max (2, UI_To_Int (Digits_Value (P_Type)));
begin
if Esize (P_Type) <= 32 then
Len := Len + 6;
elsif Esize (P_Type) = 64 then
Len := Len + 7;
else
Len := Len + 8;
end if;
Fold_Uint (N, UI_From_Int (Len), Static);
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, Static);
-- 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 (P_Type),
Static);
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_[Wide_]Character.
elsif Is_Standard_Character_Type (P_Type) then
W := 0;
-- Set W larger if needed
for J in UI_To_Int (Lo) .. UI_To_Int (Hi) loop
-- All wide characters look like Hex_hhhhhhhh
if J > 255 then
-- No need to compute this more than once
exit;
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
| CR
| EM
| FF
| FS
| GS
| HT
| LF
| MW
| PM
| RI
| RS
| SI
| SO
| ST
| US
| VT
=>
Wt := 2;
when ACK
| APC
| BEL
| BPH
| CAN
| CCH
| CSI
| DC1
| DC2
| DC3
| DC4
| DCS
| DEL
| DLE
| ENQ
| EOT
| EPA
| ESA
| ESC
| ETB
| ETX
| HTJ
| HTS
| NAK
| NBH
| NEL
| NUL
| OSC
| PLD
| PLU
| PU1
| PU2
| SCI
| SOH
| SOS
| SPA
| SS2
| SS3
| SSA
| STS
| STX
| SUB
| SYN
| VTS
=>
Wt := 3;
when Space .. Tilde
| No_Break_Space .. LC_Y_Diaeresis
=>
-- Special case of soft hyphen in Ada 2005
if C = Character'Val (16#AD#)
and then Ada_Version >= Ada_2005
then
Wt := 11;
else
Wt := 3;
end if;
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;
-- User declared enum type with discard names
elsif Discard_Names (R) then
-- If range is null, result is zero, that has already
-- been dealt with, so what we need is the power of ten
-- that accommodates the Pos of the largest value, which
-- is the high bound of the range + one for the space.
W := 1;
T := Hi;
while T /= 0 loop
T := T / 10;
W := W + 1;
end loop;
-- Only remaining possibility is user declared enum type
-- with normal case of Discard_Names not active.
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_[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), Static);
end;
end if;
end if;
-- The following attributes denote functions that cannot be folded
when Attribute_From_Any
| Attribute_To_Any
| Attribute_TypeCode
=>
null;
-- 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 or earlier in
-- this procedure.
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_Compiler_Version
| Attribute_Count
| Attribute_Default_Bit_Order
| Attribute_Default_Scalar_Storage_Order
| Attribute_Deref
| Attribute_Elaborated
| Attribute_Elab_Body
| Attribute_Elab_Spec
| Attribute_Elab_Subp_Body
| Attribute_Enabled
| Attribute_External_Tag
| Attribute_Fast_Math
| Attribute_First_Bit
| Attribute_Img
| Attribute_Input
| Attribute_Last_Bit
| Attribute_Library_Level
| Attribute_Maximum_Alignment
| Attribute_Old
| Attribute_Output
| Attribute_Partition_ID
| Attribute_Pool_Address
| Attribute_Position
| Attribute_Priority
| Attribute_Read
| Attribute_Result
| Attribute_Scalar_Storage_Order
| Attribute_Simple_Storage_Pool
| Attribute_Storage_Pool
| Attribute_Storage_Size
| Attribute_Storage_Unit
| Attribute_Stub_Type
| Attribute_System_Allocator_Alignment
| Attribute_Tag
| Attribute_Target_Name
| Attribute_Terminated
| Attribute_To_Address
| Attribute_Type_Key
| Attribute_Unchecked_Access
| Attribute_Universal_Literal_String
| Attribute_Unrestricted_Access
| Attribute_Valid
| Attribute_Valid_Scalars
| Attribute_Value
| Attribute_Wchar_T_Size
| Attribute_Wide_Value
| Attribute_Wide_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.
-- An exception is the GNAT attribute Constrained_Array which is
-- defined to be a static attribute in all cases.
if Nkind_In (N, N_Integer_Literal,
N_Real_Literal,
N_Character_Literal,
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;
--------------------------------
-- Name_Implies_Lvalue_Prefix --
--------------------------------
function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean is
pragma Assert (Is_Attribute_Name (Nam));
begin
return Attribute_Name_Implies_Lvalue_Prefix (Get_Attribute_Id (Nam));
end Name_Implies_Lvalue_Prefix;
-----------------------
-- 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);
Btyp : constant Entity_Id := Base_Type (Typ);
Des_Btyp : Entity_Id;
Index : Interp_Index;
It : Interp;
Nom_Subt : Entity_Id;
procedure Accessibility_Message;
-- Error, or warning within an instance, if the static accessibility
-- rules of 3.10.2 are violated.
function Declared_Within_Generic_Unit
(Entity : Entity_Id;
Generic_Unit : Node_Id) return Boolean;
-- Returns True if Declared_Entity is declared within the declarative
-- region of Generic_Unit; otherwise returns False.
---------------------------
-- Accessibility_Message --
---------------------------
procedure Accessibility_Message is
Indic : Node_Id := Parent (Parent (N));
begin
-- 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_Warn := SPARK_Mode /= On;
Error_Msg_F
("non-local pointer cannot point to local object<<", P);
Error_Msg_F ("\Program_Error [<<", P);
Rewrite (N,
Make_Raise_Program_Error (Loc,
Reason => PE_Accessibility_Check_Failed));
Set_Etype (N, Typ);
return;
else
Error_Msg_F ("non-local pointer cannot point to local object", P);
-- Check for case where we have a missing access definition
if Is_Record_Type (Current_Scope)
and then
Nkind_In (Parent (N), N_Discriminant_Association,
N_Index_Or_Discriminant_Constraint)
then
Indic := Parent (Parent (N));
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 if;
end if;
end Accessibility_Message;
----------------------------------
-- Declared_Within_Generic_Unit --
----------------------------------
function Declared_Within_Generic_Unit
(Entity : Entity_Id;
Generic_Unit : Node_Id) return Boolean
is
Generic_Encloser : Node_Id := Enclosing_Generic_Unit (Entity);
begin
while Present (Generic_Encloser) loop
if Generic_Encloser = Generic_Unit then
return True;
end if;
-- We have to step to the scope of the generic's entity, because
-- otherwise we'll just get back the same generic.
Generic_Encloser :=
Enclosing_Generic_Unit
(Scope (Defining_Entity (Generic_Encloser)));
end loop;
return False;
end Declared_Within_Generic_Unit;
-- Start of processing for Resolve_Attribute
begin
-- If error during analysis, no point in continuing, except for array
-- types, where we get better recovery by using unconstrained indexes
-- 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
=>
-- Note possible modification if we have a variable
if Is_Variable (P) then
declare
PN : constant Node_Id := Parent (N);
Nm : Node_Id;
Note : Boolean := True;
-- Skip this for the case of Unrestricted_Access occuring in
-- the context of a Valid check, since this otherwise leads
-- to a missed warning (the Valid check does not really
-- modify!) If this case, Note will be reset to False.
-- Skip it as well if the type is an Acccess_To_Constant,
-- given that no use of the value can modify the prefix.
begin
if Attr_Id = Attribute_Unrestricted_Access
and then Nkind (PN) = N_Function_Call
then
Nm := Name (PN);
if Nkind (Nm) = N_Expanded_Name
and then Chars (Nm) = Name_Valid
and then Nkind (Prefix (Nm)) = N_Identifier
and then Chars (Prefix (Nm)) = Name_Attr_Long_Float
then
Note := False;
end if;
elsif Is_Access_Constant (Typ) then
Note := False;
end if;
if Note then
Note_Possible_Modification (P, Sure => False);
end if;
end;
end if;
-- The following comes from a query concerning improper use of
-- universal_access in equality tests involving anonymous access
-- types. Another good reason for 'Ref, but for now disable the
-- test, which breaks several filed tests???
if Ekind (Typ) = E_Anonymous_Access_Type
and then Nkind_In (Parent (N), N_Op_Eq, N_Op_Ne)
and then False
then
Error_Msg_N ("need unique type to resolve 'Access", N);
Error_Msg_N ("\qualify attribute with some access type", N);
end if;
-- Case where prefix is an entity name
if Is_Entity_Name (P) then
-- Deal with case where prefix itself is overloaded
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);
Set_Is_Overloaded (N, False);
Generate_Reference (Entity (P), P);
exit;
end if;
Get_Next_Interp (Index, It);
end loop;
-- If Prefix is a subprogram name, this reference freezes,
-- but not if within spec expression mode. The profile of
-- the subprogram is not frozen at this point.
if not In_Spec_Expression then
Freeze_Before (N, Entity (P), Do_Freeze_Profile => False);
end if;
-- If it is a type, there is nothing to resolve.
-- If it is a subprogram, do not freeze its profile.
-- If it is an object, complete its resolution.
elsif Is_Overloadable (Entity (P)) then
if not In_Spec_Expression then
Freeze_Before (N, Entity (P), Do_Freeze_Profile => False);
end if;
-- Nothing to do if prefix is a type name
elsif Is_Type (Entity (P)) then
null;
-- Otherwise non-overloaded other case, resolve the prefix
else
Resolve (P);
end if;
-- Some further error checks
Error_Msg_Name_1 := Aname;
if not Is_Entity_Name (P) then
null;
elsif Is_Overloadable (Entity (P))
and then Is_Abstract_Subprogram (Entity (P))
then
Error_Msg_F ("prefix of % attribute cannot be abstract", P);
Set_Etype (N, Any_Type);
elsif Ekind (Entity (P)) = E_Enumeration_Literal then
Error_Msg_F
("prefix of % attribute cannot be enumeration literal", P);
Set_Etype (N, Any_Type);
-- An attempt to take 'Access of a function that renames an
-- enumeration literal. Issue a specialized error message.
elsif Ekind (Entity (P)) = E_Function
and then Present (Alias (Entity (P)))
and then Ekind (Alias (Entity (P))) = E_Enumeration_Literal
then
Error_Msg_F
("prefix of % attribute cannot be function renaming "
& "an enumeration literal", P);
Set_Etype (N, Any_Type);
elsif Convention (Entity (P)) = Convention_Intrinsic then
Error_Msg_F ("prefix of % attribute cannot be intrinsic", P);
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_In (Btyp, E_Access_Protected_Subprogram_Type,
E_Access_Subprogram_Type,
E_Anonymous_Access_Protected_Subprogram_Type,
E_Anonymous_Access_Subprogram_Type)
then
-- Deal with convention mismatch
if Convention (Designated_Type (Btyp)) /=
Convention (Entity (P))
then
-- The rule in 6.3.1 (8) deserves a special error
-- message.
if Convention (Btyp) = Convention_Intrinsic
and then Nkind (Parent (N)) = N_Procedure_Call_Statement
and then Is_Entity_Name (Name (Parent (N)))
and then Inside_A_Generic
then
declare
Subp : constant Entity_Id :=
Entity (Name (Parent (N)));
begin
if Convention (Subp) = Convention_Intrinsic then
Error_Msg_FE
("?subprogram and its formal access "
& "parameters have convention Intrinsic",
Parent (N), Subp);
Error_Msg_N
("actual cannot be access attribute", N);
end if;
end;
else
Error_Msg_FE
("subprogram & has wrong convention", P, Entity (P));
Error_Msg_Sloc := Sloc (Btyp);
Error_Msg_FE ("\does not match & declared#", P, Btyp);
end if;
if not Is_Itype (Btyp)
and then not Has_Convention_Pragma (Btyp)
then
Error_Msg_FE
("\probable missing pragma Convention for &",
P, Btyp);
end if;
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_F
("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).
-- This rule also applies within the private part of an
-- instantiation. This rule does not apply to anonymous
-- access-to-subprogram types in access parameters.
elsif Attr_Id = Attribute_Access
and then not In_Instance_Body
and then
(Ekind (Btyp) = E_Access_Subprogram_Type
or else Is_Local_Anonymous_Access (Btyp))
and then Subprogram_Access_Level (Entity (P)) >
Type_Access_Level (Btyp)
then
Error_Msg_F
("subprogram must not be deeper than access type", P);
-- Check the restriction of 3.10.2(32) that disallows the
-- access attribute within a generic body when the ultimate
-- ancestor of the type of the attribute is declared outside
-- of the generic unit and the subprogram is declared within
-- that generic unit. This includes any such attribute that
-- occurs within the body of a generic unit that is a child
-- of the generic unit where the subprogram is declared.
-- The rule also prohibits applying the attribute when the
-- access type is a generic formal access type (since the
-- level of the actual type is not known). This restriction
-- does not apply when the attribute type is an anonymous
-- access-to-subprogram type. Note that this check was
-- revised by AI-229, because the original Ada 95 rule
-- was too lax. The original rule only applied when the
-- subprogram was declared within the body of the generic,
-- which allowed the possibility of dangling references).
-- The rule was also too strict in some cases, in that it
-- didn't permit the access to be declared in the generic
-- spec, whereas the revised rule does (as long as it's not
-- a formal type).
-- There are a couple of subtleties of the test for applying
-- the check that are worth noting. First, we only apply it
-- when the levels of the subprogram and access type are the
-- same (the case where the subprogram is statically deeper
-- was applied above, and the case where the type is deeper
-- is always safe). Second, we want the check to apply
-- within nested generic bodies and generic child unit
-- bodies, but not to apply to an attribute that appears in
-- the generic unit's specification. This is done by testing
-- that the attribute's innermost enclosing generic body is
-- not the same as the innermost generic body enclosing the
-- generic unit where the subprogram is declared (we don't
-- want the check to apply when the access attribute is in
-- the spec and there's some other generic body enclosing
-- generic). Finally, there's no point applying the check
-- when within an instance, because any violations will have
-- been caught by the compilation of the generic unit.
-- We relax this check in Relaxed_RM_Semantics mode for
-- compatibility with legacy code for use by Ada source
-- code analyzers (e.g. CodePeer).
elsif Attr_Id = Attribute_Access
and then not Relaxed_RM_Semantics
and then not In_Instance
and then Present (Enclosing_Generic_Unit (Entity (P)))
and then Present (Enclosing_Generic_Body (N))
and then Enclosing_Generic_Body (N) /=
Enclosing_Generic_Body
(Enclosing_Generic_Unit (Entity (P)))
and then Subprogram_Access_Level (Entity (P)) =
Type_Access_Level (Btyp)
and then Ekind (Btyp) /=
E_Anonymous_Access_Subprogram_Type
and then Ekind (Btyp) /=
E_Anonymous_Access_Protected_Subprogram_Type
then
-- The attribute type's ultimate ancestor must be
-- declared within the same generic unit as the
-- subprogram is declared (including within another
-- nested generic unit). The error message is
-- specialized to say "ancestor" for the case where the
-- access type is not its own ancestor, since saying
-- simply "access type" would be very confusing.
if not Declared_Within_Generic_Unit
(Root_Type (Btyp),
Enclosing_Generic_Unit (Entity (P)))
then
Error_Msg_N
("''Access attribute not allowed in generic body",
N);
if Root_Type (Btyp) = Btyp then
Error_Msg_NE
("\because " &
"access type & is declared outside " &
"generic unit (RM 3.10.2(32))", N, Btyp);
else
Error_Msg_NE
("\because ancestor of " &
"access type & is declared outside " &
"generic unit (RM 3.10.2(32))", N, Btyp);
end if;
Error_Msg_NE
("\move ''Access to private part, or " &
"(Ada 2005) use anonymous access type instead of &",
N, Btyp);
-- If the ultimate ancestor of the attribute's type is
-- a formal type, then the attribute is illegal because
-- the actual type might be declared at a higher level.
-- The error message is specialized to say "ancestor"
-- for the case where the access type is not its own
-- ancestor, since saying simply "access type" would be
-- very confusing.
elsif Is_Generic_Type (Root_Type (Btyp)) then
if Root_Type (Btyp) = Btyp then
Error_Msg_N
("access type must not be a generic formal type",
N);
else
Error_Msg_N
("ancestor access type must not be a generic " &
"formal type", N);
end if;
end if;
end if;
end if;
-- If this is a renaming, an inherited operation, or a
-- subprogram instance, use the original entity. This may make
-- the node type-inconsistent, so this transformation can only
-- be done if the node will not be reanalyzed. In particular,
-- if it is within a default expression, the transformation
-- must be delayed until the default subprogram is created for
-- it, when the enclosing subprogram is frozen.
if Is_Entity_Name (P)
and then Is_Overloadable (Entity (P))
and then Present (Alias (Entity (P)))
and then Expander_Active
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_F
("attribute% cannot be applied to protected operation", P);
end if;
Resolve (Prefix (P));
Generate_Reference (Entity (Selector_Name (P)), P);
-- Implement check implied by 3.10.2 (18.1/2) : F.all'access is
-- statically illegal if F is an anonymous access to subprogram.
elsif Nkind (P) = N_Explicit_Dereference
and then Is_Entity_Name (Prefix (P))
and then Ekind (Etype (Entity (Prefix (P)))) =
E_Anonymous_Access_Subprogram_Type
then
Error_Msg_N ("anonymous access to subprogram "
& "has deeper accessibility than any master", P);
elsif Is_Overloaded (P) then
-- Use the designated type of the context to disambiguate
-- Note that this was not strictly conformant to Ada 95,
-- but was the implementation adopted by most Ada 95 compilers.
-- The use of the context type to resolve an Access attribute
-- reference is now mandated in AI-235 for Ada 2005.
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);
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 the reference is a
-- default-initialized aggregate component for a self-referential
-- type the reference is legal.
if not (Ekind (Btyp) = E_Access_Subprogram_Type
or else Ekind (Btyp) = E_Anonymous_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 Ekind (Btyp)
= E_Anonymous_Access_Protected_Subprogram_Type
or else Is_Access_Constant (Btyp)
or else Is_Variable (P)
or else Attr_Id = Attribute_Unrestricted_Access)
then
if Is_Entity_Name (P)
and then Is_Type (Entity (P))
then
-- Legality of a self-reference through an access
-- attribute has been verified in Analyze_Access_Attribute.
null;
elsif Comes_From_Source (N) then
Error_Msg_F ("access-to-variable designates constant", P);
end if;
end if;
Des_Btyp := Designated_Type (Btyp);
if Ada_Version >= Ada_2005
and then Is_Incomplete_Type (Des_Btyp)
then
-- Ada 2005 (AI-412): If the (sub)type is a limited view of an
-- imported entity, and the non-limited view is visible, make
-- use of it. If it is an incomplete subtype, use the base type
-- in any case.
if From_Limited_With (Des_Btyp)
and then Present (Non_Limited_View (Des_Btyp))
then
Des_Btyp := Non_Limited_View (Des_Btyp);
elsif Ekind (Des_Btyp) = E_Incomplete_Subtype then
Des_Btyp := Etype (Des_Btyp);
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
-- Ada 2005 (AI-230): Check the accessibility of anonymous
-- access types for stand-alone objects, record and array
-- components, and return objects. For a component definition
-- the level is the same of the enclosing composite type.
if Ada_Version >= Ada_2005
and then (Is_Local_Anonymous_Access (Btyp)
-- Handle cases where Btyp is the anonymous access
-- type of an Ada 2012 stand-alone object.
or else Nkind (Associated_Node_For_Itype (Btyp)) =
N_Object_Declaration)
and then
Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
and then Attr_Id = Attribute_Access
then
-- In an instance, this is a runtime check, but one we know
-- will fail, so generate an appropriate warning. As usual,
-- this kind of warning is an error in SPARK mode.
if In_Instance_Body then
Error_Msg_Warn := SPARK_Mode /= On;
Error_Msg_F
("non-local pointer cannot point to local object<<", P);
Error_Msg_F ("\Program_Error [<<", P);
Rewrite (N,
Make_Raise_Program_Error (Loc,
Reason => PE_Accessibility_Check_Failed));
Set_Etype (N, Typ);
else
Error_Msg_F
("non-local pointer cannot point to local object", P);
end if;
end if;
if Is_Dependent_Component_Of_Mutable_Object (P) then
Error_Msg_F
("illegal attribute for discriminant-dependent component",
P);
end if;
-- Check static matching rule of 3.10.2(27). 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 := Base_Type (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_FE
("type of prefix: & not compatible",
P, Nom_Subt);
Error_Msg_FE
("\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_FE
("type of prefix: & is not covered", P, Nom_Subt);
Error_Msg_FE
("\by &, the expected designated type" &
" (RM 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;
-- Ada 2005 (AI-363): Require static matching when designated
-- type has discriminants and a constrained partial view, since
-- in general objects of such types are mutable, so we can't
-- allow the access value to designate a constrained object
-- (because access values must be assumed to designate mutable
-- objects when designated type does not impose a constraint).
elsif Subtypes_Statically_Match (Des_Btyp, Nom_Subt) then
null;
elsif Has_Discriminants (Designated_Type (Typ))
and then not Is_Constrained (Des_Btyp)
and then
(Ada_Version < Ada_2005
or else
not Object_Type_Has_Constrained_Partial_View
(Typ => Designated_Type (Base_Type (Typ)),
Scop => Current_Scope))
then
null;
else
Error_Msg_F
("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 Ekind (Btyp) = E_General_Access_Type
and then
Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
then
Accessibility_Message;
return;
end if;
end if;
if Ekind_In (Btyp, E_Access_Protected_Subprogram_Type,
E_Anonymous_Access_Protected_Subprogram_Type)
then
if Is_Entity_Name (P)
and then not Is_Protected_Type (Scope (Entity (P)))
then
Error_Msg_F ("context requires a protected subprogram", P);
-- Check accessibility of protected object against that of the
-- access type, but only on user code, because the expander
-- creates access references for handlers. If the context is an
-- anonymous_access_to_protected, there are no accessibility
-- checks either. Omit check entirely for Unrestricted_Access.
elsif Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
and then Comes_From_Source (N)
and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type
and then Attr_Id /= Attribute_Unrestricted_Access
then
Accessibility_Message;
return;
-- AI05-0225: If the context is not an access to protected
-- function, the prefix must be a variable, given that it may
-- be used subsequently in a protected call.
elsif Nkind (P) = N_Selected_Component
and then not Is_Variable (Prefix (P))
and then Ekind (Entity (Selector_Name (P))) /= E_Function
then
Error_Msg_N
("target object of access to protected procedure "
& "must be variable", N);
elsif Is_Entity_Name (P) then
Check_Internal_Protected_Use (N, Entity (P));
end if;
elsif Ekind_In (Btyp, E_Access_Subprogram_Type,
E_Anonymous_Access_Subprogram_Type)
and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type
then
Error_Msg_F ("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;
-- The context may be a constrained access type (however ill-
-- advised such subtypes might be) so in order to generate a
-- constraint check when needed set the type of the attribute
-- reference to the base type of the context.
Set_Etype (N, Btyp);
-- 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_F
("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_F
("access to volatile object cannot yield access-to-" &
"non-volatile type", P);
end if;
end if;
-- Check for unrestricted access where expected type is a thin
-- pointer to an unconstrained array.
if Non_Aliased_Prefix (N)
and then Has_Size_Clause (Typ)
and then RM_Size (Typ) = System_Address_Size
then
declare
DT : constant Entity_Id := Designated_Type (Typ);
begin
if Is_Array_Type (DT) and then not Is_Constrained (DT) then
Error_Msg_N
("illegal use of Unrestricted_Access attribute", P);
Error_Msg_N
("\attempt to generate thin pointer to unaliased "
& "object", P);
end if;
end;
end if;
-- Mark that address of entity is taken in case of
-- 'Unrestricted_Access or in case of a subprogram.
if Is_Entity_Name (P)
and then (Attr_Id = Attribute_Unrestricted_Access
or else Is_Subprogram (Entity (P)))
then
Set_Address_Taken (Entity (P));
end if;
-- Deal with possible elaboration check
if Is_Entity_Name (P) and then Is_Subprogram (Entity (P)) then
declare
Subp_Id : constant Entity_Id := Entity (P);
Scop : constant Entity_Id := Scope (Subp_Id);
Subp_Decl : constant Node_Id :=
Unit_Declaration_Node (Subp_Id);
Flag_Id : Entity_Id;
Subp_Body : Node_Id;
-- If the access has been taken and the body of the subprogram
-- has not been see yet, indirect calls must be protected with
-- elaboration checks. We have the proper elaboration machinery
-- for subprograms declared in packages, but within a block or
-- a subprogram the body will appear in the same declarative
-- part, and we must insert a check in the eventual body itself
-- using the elaboration flag that we generate now. The check
-- is then inserted when the body is expanded. This processing
-- is not needed for a stand alone expression function because
-- the internally generated spec and body are always inserted
-- as a pair in the same declarative list.
begin
if Expander_Active
and then Comes_From_Source (Subp_Id)
and then Comes_From_Source (N)
and then In_Open_Scopes (Scop)
and then Ekind_In (Scop, E_Block, E_Procedure, E_Function)
and then not Has_Completion (Subp_Id)
and then No (Elaboration_Entity (Subp_Id))
and then Nkind (Subp_Decl) = N_Subprogram_Declaration
and then Nkind (Original_Node (Subp_Decl)) /=
N_Expression_Function
then
-- Create elaboration variable for it
Flag_Id := Make_Temporary (Loc, 'E');
Set_Elaboration_Entity (Subp_Id, Flag_Id);
Set_Is_Frozen (Flag_Id);
-- Insert declaration for flag after subprogram
-- declaration. Note that attribute reference may
-- appear within a nested scope.
Insert_After_And_Analyze (Subp_Decl,
Make_Object_Declaration (Loc,
Defining_Identifier => Flag_Id,
Object_Definition =>
New_Occurrence_Of (Standard_Short_Integer, Loc),
Expression =>
Make_Integer_Literal (Loc, Uint_0)));
end if;
-- Taking the 'Access of an expression function freezes its
-- expression (RM 13.14 10.3/3). This does not apply to an
-- expression function that acts as a completion because the
-- generated body is immediately analyzed and the expression
-- is automatically frozen.
if Is_Expression_Function (Subp_Id)
and then Present (Corresponding_Body (Subp_Decl))
then
Subp_Body :=
Unit_Declaration_Node (Corresponding_Body (Subp_Decl));
-- The body has already been analyzed when the expression
-- function acts as a completion.
if Analyzed (Subp_Body) then
null;
-- Attribute 'Access may appear within the generated body
-- of the expression function subject to the attribute:
-- function F is (... F'Access ...);
-- If the expression function is on the scope stack, then
-- the body is currently being analyzed. Do not reanalyze
-- it because this will lead to infinite recursion.
elsif In_Open_Scopes (Subp_Id) then
null;
-- If reference to the expression function appears in an
-- inner scope, for example as an actual in an instance,
-- this is not a freeze point either.
elsif Scope (Subp_Id) /= Current_Scope then
null;
-- Analyze the body of the expression function to freeze
-- the expression. This takes care of the case where the
-- 'Access is part of dispatch table initialization and
-- the generated body of the expression function has not
-- been analyzed yet.
else
Analyze (Subp_Body);
end if;
end if;
end;
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, Sure => False);
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_F
("prefix of % attribute cannot be overloaded", P);
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);
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;
if Is_Entity_Name (P) then
Set_Address_Taken (Entity (P));
end if;
if Nkind (P) = N_Slice then
-- Arr (X .. Y)'address is identical to Arr (X)'address,
-- even if the array is packed and the slice itself is not
-- addressable. Transform the prefix into an indexed component.
-- Note that the transformation is safe only if we know that
-- the slice is non-null. That is because a null slice can have
-- an out of bounds index value.
-- Right now, gigi blows up if given 'Address on a slice as a
-- result of some incorrect freeze nodes generated by the front
-- end, and this covers up that bug in one case, but the bug is
-- likely still there in the cases not handled by this code ???
-- It's not clear what 'Address *should* return for a null
-- slice with out of bounds indexes, this might be worth an ARG
-- discussion ???
-- One approach would be to do a length check unconditionally,
-- and then do the transformation below unconditionally, but
-- analyze with checks off, avoiding the problem of the out of
-- bounds index. This approach would interpret the address of
-- an out of bounds null slice as being the address where the
-- array element would be if there was one, which is probably
-- as reasonable an interpretation as any ???
declare
Loc : constant Source_Ptr := Sloc (P);
D : constant Node_Id := Discrete_Range (P);
Lo : Node_Id;
begin
if Is_Entity_Name (D)
and then
Not_Null_Range
(Type_Low_Bound (Entity (D)),
Type_High_Bound (Entity (D)))
then
Lo :=
Make_Attribute_Reference (Loc,
Prefix => (New_Occurrence_Of (Entity (D), Loc)),
Attribute_Name => Name_First);
elsif Nkind (D) = N_Range
and then Not_Null_Range (Low_Bound (D), High_Bound (D))
then
Lo := Low_Bound (D);
else
Lo := Empty;
end if;
if Present (Lo) then
Rewrite (P,
Make_Indexed_Component (Loc,
Prefix => Relocate_Node (Prefix (P)),
Expressions => New_List (Lo)));
Analyze_And_Resolve (P);
end if;
end;
end if;
------------------
-- 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 --
-----------
-- If the prefix of the Count attribute is an entry name it must not
-- be resolved, since this is definitely not an entry call. However,
-- if it is an element of an entry family, the index itself may
-- have to be resolved because it can be a general expression.
when Attribute_Count =>
if Nkind (P) = N_Indexed_Component
and then Is_Entity_Name (Prefix (P))
then
declare
Indx : constant Node_Id := First (Expressions (P));
Fam : constant Entity_Id := Entity (Prefix (P));
begin
Resolve (Indx, Entry_Index_Type (Fam));
Apply_Range_Check (Indx, Entry_Index_Type (Fam));
end;
end if;
----------------
-- 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;
-------------
-- Enabled --
-------------
-- Prefix of Enabled attribute is a check name, which must be treated
-- specially and not touched by Resolve.
when Attribute_Enabled =>
null;
----------------
-- Loop_Entry --
----------------
-- Do not resolve the prefix of Loop_Entry, instead wait until the
-- attribute has been expanded (see Expand_Loop_Entry_Attributes).
-- The delay ensures that any generated checks or temporaries are
-- inserted before the relocated prefix.
when Attribute_Loop_Entry =>
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;
------------------
-- Pool_Address --
------------------
when Attribute_Pool_Address =>
Resolve (P);
-----------
-- 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
Dims : List_Id;
HB : Node_Id;
LB : Node_Id;
begin
if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
Resolve (P);
end if;
Dims := Expressions (N);
HB :=
Make_Attribute_Reference (Loc,
Prefix => Duplicate_Subexpr (P, Name_Req => True),
Attribute_Name => Name_Last,
Expressions => Dims);
LB :=
Make_Attribute_Reference (Loc,
Prefix => P,
Attribute_Name => Name_First,
Expressions => (Dims));
-- Do not share the dimension indicator, if present. Even though
-- it is a static constant, its source location may be modified
-- when printing expanded code and node sharing will lead to chaos
-- in Sprint.
if Present (Dims) then
Set_Expressions (LB, New_List (New_Copy_Tree (First (Dims))));
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);
-- Ensure that the expanded range does not have side effects
Force_Evaluation (LB);
Force_Evaluation (HB);
-- 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;
------------
-- Result --
------------
-- We will only come here during the prescan of a spec expression
-- containing a Result attribute. In that case the proper Etype has
-- already been set, and nothing more needs to be done here.
when Attribute_Result =>
null;
----------------------
-- Unchecked_Access --
----------------------
-- Processing is shared with Access
-------------------------
-- Unrestricted_Access --
-------------------------
-- Processing is shared with Access
------------
-- Update --
------------
-- Resolve aggregate components in component associations
when Attribute_Update => Update : declare
Aggr : constant Node_Id := First (Expressions (N));
Typ : constant Entity_Id := Etype (Prefix (N));
Assoc : Node_Id;
Comp : Node_Id;
Expr : Node_Id;
begin
-- Set the Etype of the aggregate to that of the prefix, even
-- though the aggregate may not be a proper representation of a
-- value of the type (missing or duplicated associations, etc.)
-- Complete resolution of the prefix. Note that in Ada 2012 it
-- can be a qualified expression that is e.g. an aggregate.
Set_Etype (Aggr, Typ);
Resolve (Prefix (N), Typ);
-- For an array type, resolve expressions with the component type
-- of the array, and apply constraint checks when needed.
if Is_Array_Type (Typ) then
Assoc := First (Component_Associations (Aggr));
while Present (Assoc) loop
Expr := Expression (Assoc);
Resolve (Expr, Component_Type (Typ));
-- For scalar array components set Do_Range_Check when
-- needed. Constraint checking on non-scalar components
-- is done in Aggregate_Constraint_Checks, but only if
-- full analysis is enabled. These flags are not set in
-- the front-end in GnatProve mode.
if Is_Scalar_Type (Component_Type (Typ))
and then not Is_OK_Static_Expression (Expr)
and then not Range_Checks_Suppressed (Component_Type (Typ))
then
if Is_Entity_Name (Expr)
and then Etype (Expr) = Component_Type (Typ)
then
null;
else
Set_Do_Range_Check (Expr);
end if;
end if;
-- The choices in the association are static constants,
-- or static aggregates each of whose components belongs
-- to the proper index type. However, they must also
-- belong to the index subtype (s) of the prefix, which
-- may be a subtype (e.g. given by a slice).
-- Choices may also be identifiers with no staticness
-- requirements, in which case they must resolve to the
-- index type.
declare
C : Node_Id;
C_E : Node_Id;
Indx : Node_Id;
begin
C := First (Choices (Assoc));
while Present (C) loop
Indx := First_Index (Etype (Prefix (N)));
if Nkind (C) /= N_Aggregate then
Analyze_And_Resolve (C, Etype (Indx));
Apply_Constraint_Check (C, Etype (Indx));
Check_Non_Static_Context (C);
else
C_E := First (Expressions (C));
while Present (C_E) loop
Analyze_And_Resolve (C_E, Etype (Indx));
Apply_Constraint_Check (C_E, Etype (Indx));
Check_Non_Static_Context (C_E);
Next (C_E);
Next_Index (Indx);
end loop;
end if;
Next (C);
end loop;
end;
Next (Assoc);
end loop;
-- For a record type, use type of each component, which is
-- recorded during analysis.
else
Assoc := First (Component_Associations (Aggr));
while Present (Assoc) loop
Comp := First (Choices (Assoc));
Expr := Expression (Assoc);
if Nkind (Comp) /= N_Others_Choice
and then not Error_Posted (Comp)
then
Resolve (Expr, Etype (Entity (Comp)));
if Is_Scalar_Type (Etype (Entity (Comp)))
and then not Is_OK_Static_Expression (Expr)
and then not Range_Checks_Suppressed
(Etype (Entity (Comp)))
then
Set_Do_Range_Check (Expr);
end if;
end if;
Next (Assoc);
end loop;
end if;
end Update;
---------
-- 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);
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 Attribute_Wide_Wide_Value =>
Resolve (First (Expressions (N)), Standard_Wide_Wide_String);
when others => null;
end case;
-- If the prefix of the attribute is a class-wide type then it
-- will be expanded into a dispatching call to a predefined
-- primitive. Therefore we must check for potential violation
-- of such restriction.
if Is_Class_Wide_Type (Etype (P)) then
Check_Restriction (No_Dispatching_Calls, N);
end if;
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.
-- For an elaboration check on a subprogram, we do not freeze its type.
-- It may be declared in an unrelated scope, in particular in the case
-- of a generic function whose type may remain unelaborated.
if Attr_Id = Attribute_Elaborated then
null;
else
Freeze_Expression (P);
end if;
-- Finally perform static evaluation on the attribute reference
Analyze_Dimension (N);
Eval_Attribute (N);
end Resolve_Attribute;
------------------------
-- Set_Boolean_Result --
------------------------
procedure Set_Boolean_Result (N : Node_Id; B : Boolean) is
Loc : constant Source_Ptr := Sloc (N);
begin
if B then
Rewrite (N, New_Occurrence_Of (Standard_True, Loc));
else
Rewrite (N, New_Occurrence_Of (Standard_False, Loc));
end if;
end Set_Boolean_Result;
-------------------------------
-- Statically_Denotes_Object --
-------------------------------
function Statically_Denotes_Object (N : Node_Id) return Boolean is
Indx : Node_Id;
begin
if Is_Entity_Name (N) then
return True;
elsif Nkind (N) = N_Selected_Component
and then Statically_Denotes_Object (Prefix (N))
and then Present (Entity (Selector_Name (N)))
then
declare
Sel_Id : constant Entity_Id := Entity (Selector_Name (N));
Comp_Decl : constant Node_Id := Parent (Sel_Id);
begin
if Depends_On_Discriminant (Sel_Id) then
return False;
elsif Nkind (Parent (Parent (Comp_Decl))) = N_Variant then
return False;
else
return True;
end if;
end;
elsif Nkind (N) = N_Indexed_Component
and then Statically_Denotes_Object (Prefix (N))
and then Is_Constrained (Etype (Prefix (N)))
then
Indx := First (Expressions (N));
while Present (Indx) loop
if not Compile_Time_Known_Value (Indx)
or else Do_Range_Check (Indx)
then
return False;
end if;
Next (Indx);
end loop;
return True;
else
return False;
end if;
end Statically_Denotes_Object;
--------------------------------
-- Stream_Attribute_Available --
--------------------------------
function Stream_Attribute_Available
(Typ : Entity_Id;
Nam : TSS_Name_Type;
Partial_View : Node_Id := Empty) return Boolean
is
Etyp : Entity_Id := Typ;
-- Start of processing for Stream_Attribute_Available
begin
-- We need some comments in this body ???
if Has_Stream_Attribute_Definition (Typ, Nam) then
return True;
end if;
if Is_Class_Wide_Type (Typ) then
return not Is_Limited_Type (Typ)
or else Stream_Attribute_Available (Etype (Typ), Nam);
end if;
if Nam = TSS_Stream_Input
and then Is_Abstract_Type (Typ)
and then not Is_Class_Wide_Type (Typ)
then
return False;
end if;
if not (Is_Limited_Type (Typ)
or else (Present (Partial_View)
and then Is_Limited_Type (Partial_View)))
then
return True;
end if;
-- In Ada 2005, Input can invoke Read, and Output can invoke Write
if Nam = TSS_Stream_Input
and then Ada_Version >= Ada_2005
and then Stream_Attribute_Available (Etyp, TSS_Stream_Read)
then
return True;
elsif Nam = TSS_Stream_Output
and then Ada_Version >= Ada_2005
and then Stream_Attribute_Available (Etyp, TSS_Stream_Write)
then
return True;
end if;
-- Case of Read and Write: check for attribute definition clause that
-- applies to an ancestor type.
while Etype (Etyp) /= Etyp loop
Etyp := Etype (Etyp);
if Has_Stream_Attribute_Definition (Etyp, Nam) then
return True;
end if;
end loop;
if Ada_Version < Ada_2005 then
-- In Ada 95 mode, also consider a non-visible definition
declare
Btyp : constant Entity_Id := Implementation_Base_Type (Typ);
begin
return Btyp /= Typ
and then Stream_Attribute_Available
(Btyp, Nam, Partial_View => Typ);
end;
end if;
return False;
end Stream_Attribute_Available;
end Sem_Attr;
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