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+------------------------------------------------------------------------------
+-- --
+-- GNAT COMPILER COMPONENTS --
+-- --
+-- S E M _ A T T R --
+-- --
+-- B o d y --
+-- --
+-- Copyright (C) 1992-2013, 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_Res; use Sem_Res;
+with Sem_Type; use Sem_Type;
+with Sem_Util; use Sem_Util;
+with Stand; use Stand;
+with Sinfo; use Sinfo;
+with Sinput; use Sinput;
+with 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 Urealp; use Urealp;
+
+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
+ -- that are not included in Ada 95, but still get recognized in GNAT.
+
+ 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 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
+ -- N_Expand_Attribute_Reference in cases where this is more convenient.
+
+ function Is_Anonymous_Tagged_Base
+ (Anon : Entity_Id;
+ Typ : Entity_Id)
+ return Boolean;
+ -- For derived tagged types that constrain parent discriminants we build
+ -- an anonymous unconstrained base type. We need to recognize the relation
+ -- between the two when analyzing an access attribute for a constrained
+ -- component, before the full declaration for Typ has been analyzed, and
+ -- where therefore the prefix of the attribute does not match the enclosing
+ -- scope.
+
+ -----------------------
+ -- Analyze_Attribute --
+ -----------------------
+
+ procedure Analyze_Attribute (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Aname : constant Name_Id := Attribute_Name (N);
+ P : constant Node_Id := Prefix (N);
+ Exprs : constant List_Id := Expressions (N);
+ Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname);
+ E1 : Node_Id;
+ E2 : Node_Id;
+
+ P_Type : Entity_Id;
+ -- Type of prefix after analysis
+
+ P_Base_Type : Entity_Id;
+ -- Base type of prefix after analysis
+
+ -----------------------
+ -- Local Subprograms --
+ -----------------------
+
+ procedure Analyze_Access_Attribute;
+ -- Used for Access, Unchecked_Access, Unrestricted_Access attributes.
+ -- Internally, Id distinguishes which of the three cases is involved.
+
+ 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_Ada_2012_Attribute;
+ -- Check that we are in Ada 2012 mode for an Ada 2012 attribute, and
+ -- issue appropriate messages if not (and return to caller even in
+ -- the error case).
+
+ 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 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 Legal_Formal_Attribute;
+ -- Common processing for attributes Definite and Has_Discriminants.
+ -- Checks that prefix is generic indefinite formal type.
+
+ procedure Check_SPARK_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_Program_Unit;
+ -- Verify that prefix of attribute N is a program unit
+
+ procedure Check_Real_Type;
+ -- Verify that prefix of attribute N is fixed or float type
+
+ procedure Check_Scalar_Type;
+ -- Verify that prefix of attribute N is a scalar type
+
+ procedure Check_Standard_Prefix;
+ -- Verify that prefix of attribute N is package Standard
+
+ procedure Check_Stream_Attribute (Nam : 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_PolyORB_Attribute;
+ -- Validity checking for PolyORB/DSA attribute
+
+ 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,
+ -- UET_Address 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 S14_Attribute;
+ -- Called for all attributes defined for formal verification to check
+ -- that the S14_Extensions flag is set.
+
+ procedure Standard_Attribute (Val : Int);
+ -- Used to process attributes whose prefix is package Standard which
+ -- yield values of type Universal_Integer. The attribute reference
+ -- node is rewritten with an integer literal of the given value.
+
+ procedure Unexpected_Argument (En : Node_Id);
+ -- Signal unexpected attribute argument (En is the argument)
+
+ procedure Validate_Non_Static_Attribute_Function_Call;
+ -- Called when processing an attribute that is a function call to a
+ -- non-static function, i.e. an attribute function that either takes
+ -- non-scalar arguments or returns a non-scalar result. Verifies that
+ -- such a call does not appear in a preelaborable context.
+
+ ------------------------------
+ -- 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);
+ return True;
+ 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_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");
+ end if;
+
+ if 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;
+
+ -- Treat as call for elaboration purposes and we are all done.
+ -- Suppress this treatment under debug flag.
+
+ if 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 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.
+
+ Set_Never_Set_In_Source (Ent, False);
+
+ -- Mark entity as address taken, and kill current values
+
+ Set_Address_Taken (Ent);
+ 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 unless unrestricted case. We allow a
+ -- nonaliased prefix when within an instance because the prefix may
+ -- have been a tagged formal object, which is defined to be aliased
+ -- even when the actual might not be (other instance cases will have
+ -- been caught in the generic). Similarly, within an inlined body we
+ -- know that the attribute is legal in the original subprogram, and
+ -- therefore legal in the expansion.
+
+ if Aname /= Name_Unrestricted_Access
+ and then not Is_Aliased_View (P)
+ and then not In_Instance
+ and then not In_Inlined_Body
+ then
+ Error_Attr_P ("prefix of % attribute must be aliased");
+ Check_No_Implicit_Aliasing (P);
+ end if;
+ end Analyze_Access_Attribute;
+
+ ---------------------------------
+ -- 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_Ada_2012_Attribute --
+ ------------------------------
+
+ procedure Check_Ada_2012_Attribute is
+ begin
+ if Ada_Version < Ada_2012 then
+ Error_Msg_Name_1 := Aname;
+ Error_Msg_N
+ ("attribute % is an Ada 2012 feature", N);
+ Error_Msg_N
+ ("\unit must be compiled with -gnat2012 switch", N);
+ end if;
+ end Check_Ada_2012_Attribute;
+
+ --------------------------------
+ -- Check_Array_Or_Scalar_Type --
+ --------------------------------
+
+ procedure Check_Array_Or_Scalar_Type is
+ Index : Entity_Id;
+
+ D : Int;
+ -- Dimension number for array attributes
+
+ begin
+ -- Case of string literal or string literal subtype. These cases
+ -- cannot arise from legal Ada code, but the expander is allowed
+ -- to generate them. They require special handling because string
+ -- literal subtypes do not have standard bounds (the whole idea
+ -- of these subtypes is to avoid having to generate the bounds)
+
+ if Ekind (P_Type) = E_String_Literal_Subtype then
+ Set_Etype (N, Etype (First_Index (P_Base_Type)));
+ return;
+
+ -- Scalar types
+
+ elsif Is_Scalar_Type (P_Type) then
+ Check_Type;
+
+ if Present (E1) then
+ Error_Attr ("invalid argument in % attribute", E1);
+ else
+ Set_Etype (N, P_Base_Type);
+ return;
+ end if;
+
+ -- The following is a special test to allow 'First to apply to
+ -- private scalar types if the attribute comes from generated
+ -- code. This occurs in the case of Normalize_Scalars code.
+
+ elsif Is_Private_Type (P_Type)
+ and then Present (Full_View (P_Type))
+ and then Is_Scalar_Type (Full_View (P_Type))
+ and then not Comes_From_Source (N)
+ then
+ Set_Etype (N, Implementation_Base_Type (P_Type));
+
+ -- Array types other than string literal subtypes handled above
+
+ else
+ Check_Array_Type;
+
+ -- We know prefix is an array type, or the name of an array
+ -- object, and that the expression, if present, is static
+ -- and within the range of the dimensions of the type.
+
+ 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
+ D := UI_To_Int (Intval (E1));
+
+ for J in 1 .. D - 1 loop
+ Next_Index (Index);
+ end loop;
+
+ Set_Etype (N, Base_Type (Etype (Index)));
+ Set_Etype (E1, Standard_Integer);
+ end if;
+ end if;
+ end Check_Array_Or_Scalar_Type;
+
+ ----------------------
+ -- Check_Array_Type --
+ ----------------------
+
+ procedure Check_Array_Type is
+ D : Int;
+ -- Dimension number for array attributes
+
+ begin
+ -- If the type is a string literal type, then this must be generated
+ -- internally, and no further check is required on its legality.
+
+ if Ekind (P_Type) = E_String_Literal_Subtype then
+ return;
+
+ -- If the type is a composite, it is an illegal aggregate, no point
+ -- in going on.
+
+ elsif P_Type = Any_Composite then
+ raise Bad_Attribute;
+ end if;
+
+ -- Normal case of array type or subtype
+
+ Check_Either_E0_Or_E1;
+ 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_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 (Attribute_Name (Parent (N)) = Name_Address
+ or else
+ Attribute_Name (Parent (N)) = Name_Code_Address
+ or else
+ Attribute_Name (Parent (N)) = Name_Access)
+ then
+ Error_Msg_Name_1 := Attribute_Name (Parent (N));
+ Error_Msg_N ("illegal prefix for % attribute", Parent (N));
+ Set_Etype (Parent (N), Any_Type);
+ Set_Entity (Parent (N), Any_Type);
+ raise Bad_Attribute;
+
+ else
+ Error_Attr ("missing argument for % attribute", N);
+ end if;
+ end if;
+ end Check_E1;
+
+ --------------
+ -- Check_E2 --
+ --------------
+
+ procedure Check_E2 is
+ begin
+ if No (E1) then
+ Error_Attr ("missing arguments for % attribute (2 required)", N);
+ elsif No (E2) then
+ Error_Attr ("missing argument for % attribute (2 required)", N);
+ end if;
+ end Check_E2;
+
+ ---------------------------
+ -- Check_Either_E0_Or_E1 --
+ ---------------------------
+
+ procedure Check_Either_E0_Or_E1 is
+ begin
+ if Present (E2) then
+ Unexpected_Argument (E2);
+ end if;
+ end Check_Either_E0_Or_E1;
+
+ ----------------------
+ -- Check_Enum_Image --
+ ----------------------
+
+ procedure Check_Enum_Image is
+ Lit : Entity_Id;
+
+ begin
+ -- 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_Ada_2012_Attribute;
+ 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 No (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_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_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).
+
+ -- 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_With_Type (Typ) then
+ Error_Attr_P
+ ("prefix of % attribute cannot be an incomplete type");
+
+ else
+ if Is_Access_Type (Typ) 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_With_Type (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 Ekind (Typ) = E_Incomplete_Type
+ and then No (Full_View (Typ))
+ then
+ Error_Attr_P
+ ("prefix of % attribute cannot be an incomplete type");
+ end if;
+ end if;
+ 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_Restriction_On_Attribute --
+ ------------------------------------------
+
+ procedure Check_SPARK_Restriction_On_Attribute is
+ begin
+ Error_Msg_Name_1 := Aname;
+ Check_SPARK_Restriction ("attribute % is not allowed", P);
+ end Check_SPARK_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 the body of System.Shared_Storage.
+ -- Shared_Var_Procs. 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 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.
+
+ if Restriction_Active (No_Default_Stream_Attributes) 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_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 not Is_Indefinite_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;
+
+ -------------------
+ -- S14_Attribute --
+ -------------------
+
+ procedure S14_Attribute is
+ begin
+ if not Formal_Extensions then
+ Error_Attr
+ ("attribute % requires the use of debug switch -gnatd.V", N);
+ end if;
+ end S14_Attribute;
+
+ ------------------------
+ -- Standard_Attribute --
+ ------------------------
+
+ procedure Standard_Attribute (Val : Int) is
+ begin
+ Check_Standard_Prefix;
+ Rewrite (N, Make_Integer_Literal (Loc, Val));
+ Analyze (N);
+ end Standard_Attribute;
+
+ -------------------------
+ -- Unexpected Argument --
+ -------------------------
+
+ procedure Unexpected_Argument (En : Node_Id) is
+ begin
+ Error_Attr ("unexpected argument for % attribute", En);
+ end Unexpected_Argument;
+
+ -------------------------------------------------
+ -- Validate_Non_Static_Attribute_Function_Call --
+ -------------------------------------------------
+
+ -- This function should be moved to Sem_Dist ???
+
+ procedure Validate_Non_Static_Attribute_Function_Call is
+ begin
+ if In_Preelaborated_Unit
+ and then not In_Subprogram_Or_Concurrent_Unit
+ then
+ 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;
+
+ -- 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
+
+ if Attribute_05 (Attr_Id) and then Ada_Version < Ada_2005 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_UET_Address
+ 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;
+
+ -- Do not analyze the expressions of attribute Loop_Entry. Depending on
+ -- the number of arguments and/or the nature of the first argument, the
+ -- whole attribute reference may be rewritten into an indexed component.
+ -- In the case of two or more arguments, the expressions are analyzed
+ -- when the indexed component is analyzed, otherwise the sole argument
+ -- is preanalyzed to determine whether it is a loop name.
+
+ elsif Aname = Name_Loop_Entry then
+ E1 := First (Exprs);
+
+ if Present (E1) then
+ E2 := Next (E1);
+ end if;
+
+ else
+ E1 := First (Exprs);
+ 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;
+
+ 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;
+
+ -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current
+ -- output compiling in Ada 95 mode for the case of ambiguous prefixes.
+
+ if Ada_Version < Ada_2005
+ and then Is_Overloaded (P)
+ and then Aname /= Name_Access
+ and then Aname /= Name_Address
+ and then Aname /= Name_Code_Address
+ and then Aname /= Name_Count
+ and then Aname /= Name_Result
+ and then Aname /= Name_Unchecked_Access
+ then
+ Error_Attr ("ambiguous prefix for % attribute", P);
+
+ elsif Ada_Version >= Ada_2005
+ and then 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
+ -- Ada 2005 (AI-345): Since protected and task types have primitive
+ -- entry wrappers, the attributes Count, Caller and AST_Entry require
+ -- a context check
+
+ if Ada_Version >= Ada_2005
+ and then (Aname = Name_Count
+ or else Aname = Name_Caller
+ or else Aname = Name_AST_Entry)
+ 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;
+
+ -- In SPARK, attributes of private types are only allowed if the full
+ -- type declaration is visible.
+
+ if Is_Entity_Name (P)
+ and then Present (Entity (P)) -- needed in some cases
+ 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_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_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_Reference_To (Stand.Abort_Signal, Loc));
+ Analyze (N);
+
+ ------------
+ -- Access --
+ ------------
+
+ when Attribute_Access =>
+ Analyze_Access_Attribute;
+
+ -------------
+ -- Address --
+ -------------
+
+ when Attribute_Address =>
+ Check_E0;
+
+ -- Check for some junk cases, where we have to allow the address
+ -- attribute but it does not make much sense, so at least for now
+ -- just replace with Null_Address.
+
+ -- We also do this if the prefix is a reference to the AST_Entry
+ -- attribute. If expansion is active, the attribute will be
+ -- replaced by a function call, and address will work fine and
+ -- get the proper value, but if expansion is not active, then
+ -- the check here allows proper semantic analysis of the reference.
+
+ -- An Address attribute created by expansion is legal even when it
+ -- applies to other entity-denoting expressions.
+
+ if Is_Protected_Self_Reference (P) then
+
+ -- Address attribute on a protected object self reference is legal
+
+ null;
+
+ 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_N
+ ("cannot take Address of intrinsic subprogram", N);
+ end if;
+
+ -- Issue an error if prefix denotes an eliminated subprogram
+
+ else
+ Check_For_Eliminated_Subprogram (P, Ent);
+ end if;
+
+ 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);
+
+ 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)));
+
+ else
+ Error_Attr ("invalid prefix for % attribute", P);
+ end if;
+ end;
+
+ elsif Nkind (P) = N_Attribute_Reference
+ and then Attribute_Name (P) = Name_AST_Entry
+ then
+ Rewrite (N,
+ New_Occurrence_Of (RTE (RE_Null_Address), Sloc (N)));
+
+ elsif Is_Object_Reference (P) then
+ null;
+
+ elsif Nkind (P) = N_Selected_Component
+ and then Is_Subprogram (Entity (Selector_Name (P)))
+ then
+ null;
+
+ -- What exactly are we allowing here ??? and is this properly
+ -- documented in the sinfo documentation for this node ???
+
+ elsif not Comes_From_Source (N) then
+ null;
+
+ else
+ Error_Attr ("invalid prefix for % attribute", P);
+ end if;
+
+ Set_Etype (N, RTE (RE_Address));
+
+ ------------------
+ -- Address_Size --
+ ------------------
+
+ when Attribute_Address_Size =>
+ Standard_Attribute (System_Address_Size);
+
+ --------------
+ -- Adjacent --
+ --------------
+
+ when Attribute_Adjacent =>
+ Check_Floating_Point_Type_2;
+ Set_Etype (N, P_Base_Type);
+ Resolve (E1, P_Base_Type);
+ Resolve (E2, P_Base_Type);
+
+ ---------
+ -- Aft --
+ ---------
+
+ when Attribute_Aft =>
+ Check_Fixed_Point_Type_0;
+ Set_Etype (N, Universal_Integer);
+
+ ---------------
+ -- Alignment --
+ ---------------
+
+ when Attribute_Alignment =>
+
+ -- Don't we need more checking here, cf Size ???
+
+ Check_E0;
+ Check_Not_Incomplete_Type;
+ 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));
+
+ ---------------
+ -- AST_Entry --
+ ---------------
+
+ when Attribute_AST_Entry => AST_Entry : declare
+ Ent : Entity_Id;
+ Pref : Node_Id;
+ Ptyp : Entity_Id;
+
+ Indexed : Boolean;
+ -- Indicates if entry family index is present. Note the coding
+ -- here handles the entry family case, but in fact it cannot be
+ -- executed currently, because pragma AST_Entry does not permit
+ -- the specification of an entry family.
+
+ procedure Bad_AST_Entry;
+ -- Signal a bad AST_Entry pragma
+
+ function OK_Entry (E : Entity_Id) return Boolean;
+ -- Checks that E is of an appropriate entity kind for an entry
+ -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index
+ -- is set True for the entry family case). In the True case,
+ -- makes sure that Is_AST_Entry is set on the entry.
+
+ -------------------
+ -- Bad_AST_Entry --
+ -------------------
+
+ procedure Bad_AST_Entry is
+ begin
+ Error_Attr_P ("prefix for % attribute must be task entry");
+ end Bad_AST_Entry;
+
+ --------------
+ -- OK_Entry --
+ --------------
+
+ function OK_Entry (E : Entity_Id) return Boolean is
+ Result : Boolean;
+
+ begin
+ if Indexed then
+ Result := (Ekind (E) = E_Entry_Family);
+ else
+ Result := (Ekind (E) = E_Entry);
+ end if;
+
+ if Result then
+ if not Is_AST_Entry (E) then
+ Error_Msg_Name_2 := Aname;
+ Error_Attr ("% attribute requires previous % pragma", P);
+ end if;
+ end if;
+
+ return Result;
+ end OK_Entry;
+
+ -- Start of processing for AST_Entry
+
+ begin
+ Check_VMS (N);
+ Check_E0;
+
+ -- Deal with entry family case
+
+ if Nkind (P) = N_Indexed_Component then
+ Pref := Prefix (P);
+ Indexed := True;
+ else
+ Pref := P;
+ Indexed := False;
+ end if;
+
+ Ptyp := Etype (Pref);
+
+ if Ptyp = Any_Type or else Error_Posted (Pref) then
+ return;
+ end if;
+
+ -- If the prefix is a selected component whose prefix is of an
+ -- access type, then introduce an explicit dereference.
+ -- ??? Could we reuse Check_Dereference here?
+
+ if Nkind (Pref) = N_Selected_Component
+ and then Is_Access_Type (Ptyp)
+ then
+ Rewrite (Pref,
+ Make_Explicit_Dereference (Sloc (Pref),
+ Relocate_Node (Pref)));
+ Analyze_And_Resolve (Pref, Designated_Type (Ptyp));
+ end if;
+
+ -- Prefix can be of the form a.b, where a is a task object
+ -- and b is one of the entries of the corresponding task type.
+
+ if Nkind (Pref) = N_Selected_Component
+ and then OK_Entry (Entity (Selector_Name (Pref)))
+ and then Is_Object_Reference (Prefix (Pref))
+ and then Is_Task_Type (Etype (Prefix (Pref)))
+ then
+ null;
+
+ -- Otherwise the prefix must be an entry of a containing task,
+ -- or of a variable of the enclosing task type.
+
+ else
+ if Nkind_In (Pref, N_Identifier, N_Expanded_Name) then
+ Ent := Entity (Pref);
+
+ if not OK_Entry (Ent)
+ or else not In_Open_Scopes (Scope (Ent))
+ then
+ Bad_AST_Entry;
+ end if;
+
+ else
+ Bad_AST_Entry;
+ end if;
+ end if;
+
+ Set_Etype (N, RTE (RE_AST_Handler));
+ end AST_Entry;
+
+ -----------------------------
+ -- 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_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_Reference_To (Entity (N), Loc));
+ Analyze (N);
+ end Base;
+
+ ---------
+ -- Bit --
+ ---------
+
+ when Attribute_Bit => Bit :
+ begin
+ 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);
+ end Bit;
+
+ ---------------
+ -- Bit_Order --
+ ---------------
+
+ when Attribute_Bit_Order => Bit_Order :
+ begin
+ Check_E0;
+ Check_Type;
+
+ if not Is_Record_Type (P_Type) then
+ Error_Attr_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);
+ end Bit_Order;
+
+ ------------------
+ -- Bit_Position --
+ ------------------
+
+ -- Note: in generated code, we can have a Bit_Position attribute
+ -- applied to a (naked) record component (i.e. the prefix is an
+ -- identifier that references an E_Component or E_Discriminant
+ -- entity directly, and this is interpreted as expected by Gigi.
+ -- The following code will not tolerate such usage, but when the
+ -- expander creates this special case, it marks it as analyzed
+ -- immediately and sets an appropriate type.
+
+ when Attribute_Bit_Position =>
+ if Comes_From_Source (N) then
+ Check_Component;
+ end if;
+
+ Set_Etype (N, Universal_Integer);
+
+ ------------------
+ -- Body_Version --
+ ------------------
+
+ when Attribute_Body_Version =>
+ Check_E0;
+ Check_Program_Unit;
+ Set_Etype (N, RTE (RE_Version_String));
+
+ --------------
+ -- Callable --
+ --------------
+
+ when Attribute_Callable =>
+ Check_E0;
+ Set_Etype (N, Standard_Boolean);
+ Check_Task_Prefix;
+
+ ------------
+ -- Caller --
+ ------------
+
+ when Attribute_Caller => Caller : declare
+ Ent : Entity_Id;
+ S : Entity_Id;
+
+ begin
+ Check_E0;
+
+ if Nkind_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 (Attribute_Name (P) = Name_Elab_Body
+ or else
+ Attribute_Name (P) = Name_Elab_Spec)
+ then
+ null;
+
+ elsif not Is_Entity_Name (P)
+ or else (Ekind (Entity (P)) /= E_Function
+ and then
+ Ekind (Entity (P)) /= E_Procedure)
+ then
+ Error_Attr ("invalid prefix for % attribute", P);
+ Set_Address_Taken (Entity (P));
+
+ -- 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);
+
+ --------------------
+ -- 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 classwide type is ???
+ -- has unknown discriminants.
+
+ if Has_Discriminants (P_Type)
+ or else Has_Unknown_Discriminants (P_Type)
+ or else
+ (Is_Access_Type (P_Type)
+ and then Has_Discriminants (Designated_Type (P_Type)))
+ then
+ return;
+
+ -- Also allow an object of a generic type if extensions allowed
+ -- and allow this for any type at all.
+
+ elsif (Is_Generic_Type (P_Type)
+ or else Is_Generic_Actual_Type (P_Type))
+ and then Extensions_Allowed
+ then
+ return;
+ end if;
+ end if;
+
+ -- Fall through if bad prefix
+
+ Error_Attr_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_Loop, E_Block, E_Entry, E_Entry_Family)
+ 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 :
+ begin
+ Check_Standard_Prefix;
+
+ if Bytes_Big_Endian then
+ Rewrite (N,
+ Make_Integer_Literal (Loc, False_Value));
+ else
+ Rewrite (N,
+ Make_Integer_Literal (Loc, True_Value));
+ end if;
+
+ Set_Etype (N, Universal_Integer);
+ Set_Is_Static_Expression (N);
+ end Default_Bit_Order;
+
+ --------------
+ -- Definite --
+ --------------
+
+ when Attribute_Definite =>
+ Legal_Formal_Attribute;
+
+ -----------
+ -- Delta --
+ -----------
+
+ when Attribute_Delta =>
+ Check_Fixed_Point_Type_0;
+ Set_Etype (N, Universal_Real);
+
+ ------------
+ -- Denorm --
+ ------------
+
+ when Attribute_Denorm =>
+ Check_Floating_Point_Type_0;
+ Set_Etype (N, Standard_Boolean);
+
+ ---------------------
+ -- 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 => Enum_Rep : declare
+ begin
+ if Present (E1) then
+ Check_E1;
+ Check_Discrete_Type;
+ Resolve (E1, P_Base_Type);
+
+ else
+ if not Is_Entity_Name (P)
+ or else (not Is_Object (Entity (P))
+ and then
+ Ekind (Entity (P)) /= E_Enumeration_Literal)
+ then
+ Error_Attr_P
+ ("prefix of % attribute must be " &
+ "discrete type/object or enum literal");
+ end if;
+ end if;
+
+ Set_Etype (N, Universal_Integer);
+ end Enum_Rep;
+
+ --------------
+ -- Enum_Val --
+ --------------
+
+ when Attribute_Enum_Val => Enum_Val : begin
+ 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;
+ end Enum_Val;
+
+ -------------
+ -- 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));
+
+ -----------
+ -- 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_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 => Image :
+ begin
+ Check_SPARK_Restriction_On_Attribute;
+ Check_Scalar_Type;
+ 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;
+ end Image;
+
+ ---------
+ -- Img --
+ ---------
+
+ when Attribute_Img => Img :
+ begin
+ 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;
+ end Img;
+
+ -----------
+ -- 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);
+
+ ---------------
+ -- 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.
+
+ procedure Convert_To_Indexed_Component;
+ -- Transform the attribute reference into an indexed component where
+ -- the prefix is Prefix'Loop_Entry and the expressions are associated
+ -- with the indexed component.
+
+ --------------------------------
+ -- 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 Nkind_In (Stmt, N_Entry_Body,
+ N_Package_Body,
+ N_Package_Declaration,
+ N_Protected_Body,
+ N_Subprogram_Body,
+ N_Task_Body)
+ 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;
+
+ ----------------------------------
+ -- Convert_To_Indexed_Component --
+ ----------------------------------
+
+ procedure Convert_To_Indexed_Component is
+ New_Loop_Entry : constant Node_Id := Relocate_Node (N);
+
+ begin
+ -- The new Loop_Entry loses its arguments. They will be converted
+ -- into the expressions of the indexed component.
+
+ Set_Expressions (New_Loop_Entry, No_List);
+
+ Rewrite (N,
+ Make_Indexed_Component (Loc,
+ Prefix => New_Loop_Entry,
+ Expressions => Exprs));
+ end Convert_To_Indexed_Component;
+
+ -- Local variables
+
+ Enclosing_Loop : Node_Id;
+ In_Loop_Assertion : Boolean := False;
+ Loop_Id : Entity_Id := Empty;
+ Scop : Entity_Id;
+ Stmt : Node_Id;
+
+ -- Start of processing for Loop_Entry
+
+ begin
+ S14_Attribute;
+
+ -- The attribute reference appears as
+ -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
+
+ -- In this case, the loop name is omitted and the arguments are part
+ -- of an indexed component. Transform the whole attribute reference
+ -- to reflect this scenario.
+
+ if Present (E2) then
+ Convert_To_Indexed_Component;
+ Analyze (N);
+ return;
+
+ -- The attribute reference appears as
+ -- Prefix'Loop_Entry (Loop_Name)
+ -- or
+ -- Prefix'Loop_Entry (Expr1)
+
+ -- Depending on what Expr1 resolves to, either rewrite the reference
+ -- into an indexed component or continue with the analysis.
+
+ elsif Present (E1) then
+
+ -- Do not expand the argument as it may have side effects. Simply
+ -- preanalyze to determine whether it is a loop 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);
+
+ -- The argument is not a loop name
+
+ else
+ Convert_To_Indexed_Component;
+ Analyze (N);
+ return;
+ 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_Immutably_Limited_Type (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 := N;
+ while Present (Stmt) loop
+
+ -- Locate the enclosing Loop_Invariant / Loop_Variant pragma (if
+ -- any). Note that when these two are expanded, we must look for
+ -- an Assertion pragma.
+
+ if Nkind (Original_Node (Stmt)) = N_Pragma
+ and then
+ (Pragma_Name (Original_Node (Stmt)) = Name_Assert
+ or else
+ Pragma_Name (Original_Node (Stmt)) = Name_Loop_Invariant
+ or else
+ Pragma_Name (Original_Node (Stmt)) = Name_Loop_Variant)
+ then
+ In_Loop_Assertion := True;
+
+ -- 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.
+
+ elsif Nkind (Stmt) = N_Loop_Statement
+ and then Present (Identifier (Stmt))
+ then
+ Enclosing_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 (Enclosing_Loop));
+ end if;
+
+ exit;
+
+ -- Prevent the search from going too far
+
+ elsif Nkind_In (Stmt, N_Entry_Body,
+ N_Package_Body,
+ N_Package_Declaration,
+ N_Protected_Body,
+ N_Subprogram_Body,
+ N_Task_Body)
+ then
+ exit;
+ end if;
+
+ Stmt := Parent (Stmt);
+ end loop;
+
+ -- Loop_Entry must appear within a Loop_Assertion pragma
+
+ if not In_Loop_Assertion then
+ Error_Attr
+ ("attribute % must appear within pragma Loop_Variant or " &
+ "Loop_Invariant", N);
+ end if;
+
+ -- A Loop_Entry that applies to a given loop statement shall not
+ -- appear within a body of accept statement, if this construct is
+ -- itself enclosed by the given loop statement.
+
+ for J in reverse 0 .. Scope_Stack.Last loop
+ Scop := Scope_Stack.Table (J).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.
+
+ if Present (Enclosing_Loop)
+ and then Entity (Identifier (Enclosing_Loop)) /= Loop_Id
+ and then not Is_Entity_Name (P)
+ then
+ Error_Attr_P ("prefix of attribute % must denote an entity");
+ end if;
+
+ Set_Etype (N, Etype (P));
+
+ -- Associate the attribute with its related loop
+
+ if No (Loop_Entry_Attributes (Loop_Id)) then
+ Set_Loop_Entry_Attributes (Loop_Id, New_Elmt_List);
+ end if;
+
+ -- A Loop_Entry may be [pre]analyzed several times, depending on the
+ -- context. Ensure that it appears only once in the attributes list
+ -- of the related loop.
+
+ Append_Unique_Elmt (N, Loop_Entry_Attributes (Loop_Id));
+ 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 =>
+ Check_E2;
+ Check_Scalar_Type;
+ Resolve (E1, P_Base_Type);
+ Resolve (E2, P_Base_Type);
+ Set_Etype (N, P_Base_Type);
+
+ ----------------------------------
+ -- Max_Alignment_For_Allocation --
+ -- Max_Size_In_Storage_Elements --
+ ----------------------------------
+
+ when Attribute_Max_Alignment_For_Allocation |
+ Attribute_Max_Size_In_Storage_Elements =>
+ Check_E0;
+ Check_Type;
+ Check_Not_Incomplete_Type;
+ Set_Etype (N, Universal_Integer);
+
+ -----------------------
+ -- Maximum_Alignment --
+ -----------------------
+
+ when Attribute_Maximum_Alignment =>
+ Standard_Attribute (Ttypes.Maximum_Alignment);
+
+ --------------------
+ -- Mechanism_Code --
+ --------------------
+
+ when Attribute_Mechanism_Code =>
+ if not Is_Entity_Name (P)
+ or else not Is_Subprogram (Entity (P))
+ then
+ Error_Attr_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_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 =>
+ Check_E2;
+ Check_Scalar_Type;
+ Resolve (E1, P_Base_Type);
+ Resolve (E2, P_Base_Type);
+ Set_Etype (N, P_Base_Type);
+
+ ---------
+ -- 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
+ CS : Entity_Id;
+ -- The enclosing scope, excluding loops for quantified expressions.
+ -- During analysis, it is the postcondition subprogram. During
+ -- pre-analysis, it is the scope of the subprogram declaration.
+
+ Prag : Node_Id;
+ -- During pre-analysis, Prag is the enclosing pragma node if any
+
+ begin
+ -- Find enclosing scopes, excluding loops
+
+ CS := Current_Scope;
+ while Ekind (CS) = E_Loop loop
+ CS := Scope (CS);
+ end loop;
+
+ -- If we are in Spec_Expression mode, this should be the prescan of
+ -- the postcondition (or contract case, or test case) pragma.
+
+ if In_Spec_Expression then
+
+ -- Check in postcondition or Ensures clause
+
+ Prag := N;
+ while not Nkind_In (Prag, N_Pragma,
+ N_Function_Specification,
+ N_Procedure_Specification,
+ N_Subprogram_Body)
+ loop
+ Prag := Parent (Prag);
+ end loop;
+
+ if Nkind (Prag) /= N_Pragma then
+ Error_Attr ("% attribute can only appear in postcondition", P);
+
+ elsif Get_Pragma_Id (Prag) = Pragma_Contract_Case
+ or else
+ Get_Pragma_Id (Prag) = Pragma_Test_Case
+ then
+ declare
+ Arg_Ens : constant Node_Id :=
+ Get_Ensures_From_CTC_Pragma (Prag);
+ Arg : Node_Id;
+
+ begin
+ Arg := N;
+ while Arg /= Prag and Arg /= Arg_Ens loop
+ Arg := Parent (Arg);
+ end loop;
+
+ if Arg /= Arg_Ens then
+ if Get_Pragma_Id (Prag) = Pragma_Contract_Case then
+ Error_Attr
+ ("% attribute misplaced inside contract case", P);
+ else
+ Error_Attr
+ ("% attribute misplaced inside test case", P);
+ end if;
+ end if;
+ end;
+
+ elsif Get_Pragma_Id (Prag) /= Pragma_Postcondition then
+ Error_Attr ("% attribute can only appear in postcondition", P);
+ end if;
+
+ -- Body case, where we must be inside a generated _Postcondition
+ -- procedure, or else the attribute use is definitely misplaced. The
+ -- postcondition itself may have generated transient scopes, and is
+ -- not necessarily the current one.
+
+ else
+ while Present (CS) and then CS /= Standard_Standard loop
+ if Chars (CS) = Name_uPostconditions then
+ exit;
+ else
+ CS := Scope (CS);
+ end if;
+ end loop;
+
+ if Chars (CS) /= Name_uPostconditions then
+ Error_Attr ("% attribute can only appear in postcondition", P);
+ end if;
+ end if;
+
+ -- Either the attribute reference is generated for a Requires
+ -- clause, in which case no expressions follow, or it is a
+ -- primary. In that case, if expressions follow, the attribute
+ -- reference is an indexable object, so rewrite the node
+ -- accordingly.
+
+ if Present (E1) then
+ Rewrite (N,
+ Make_Indexed_Component (Loc,
+ Prefix =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Relocate_Node (Prefix (N)),
+ Attribute_Name => Name_Old),
+ Expressions => Expressions (N)));
+
+ Analyze (N);
+ return;
+ end if;
+
+ Check_E0;
+
+ -- Prefix has not been analyzed yet, and its full analysis will
+ -- take place during expansion (see below).
+
+ Preanalyze_And_Resolve (P);
+ P_Type := Etype (P);
+ Set_Etype (N, P_Type);
+
+ if Is_Limited_Type (P_Type) then
+ Error_Attr ("attribute % cannot apply to limited objects", P);
+ end if;
+
+ if Is_Entity_Name (P)
+ and then Is_Constant_Object (Entity (P))
+ then
+ Error_Msg_N
+ ("??attribute Old applied to constant has no effect", P);
+ end if;
+
+ -- The attribute appears within a pre/postcondition, but refers to
+ -- an entity in the enclosing subprogram. If it is a component of
+ -- a formal its expansion might generate actual subtypes that may
+ -- be referenced in an inner context, and which must be elaborated
+ -- within the subprogram itself. If the prefix includes a function
+ -- call it may involve finalization actions that should only be
+ -- inserted when the attribute has been rewritten as a declarations.
+ -- As a result, if the prefix is not a simple name we create
+ -- a declaration for it now, and insert it at the start of the
+ -- enclosing subprogram. This is properly an expansion activity
+ -- but it has to be performed now to prevent out-of-order issues.
+
+ -- This expansion is both harmful and not needed in Alfa mode, since
+ -- the formal verification backend 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 Alfa mode.
+
+ if not Is_Entity_Name (P) and then not Alfa_Mode then
+ P_Type := Base_Type (P_Type);
+ Set_Etype (N, P_Type);
+ Set_Etype (P, P_Type);
+ Analyze_Dimension (N);
+ Expand (N);
+ 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 => Partition_Id :
+ begin
+ 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);
+ end Partition_Id;
+
+ -------------------------
+ -- 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_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_Restriction
+ ("attribute% is not allowed for type%", P);
+ end if;
+
+ Resolve (E1, P_Base_Type);
+ Set_Etype (N, P_Base_Type);
+
+ -- Nothing to do for real type case
+
+ if Is_Real_Type (P_Type) then
+ null;
+
+ -- If not modular type, test for overflow check required
+
+ else
+ if not Is_Modular_Integer_Type (P_Type)
+ and then not Range_Checks_Suppressed (P_Base_Type)
+ then
+ Enable_Range_Check (E1);
+ end if;
+ end if;
+
+ --------------
+ -- 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;
+
+ -- 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
+ CS : Entity_Id;
+ -- The enclosing scope, excluding loops for quantified expressions
+
+ PS : Entity_Id;
+ -- During analysis, CS is the postcondition subprogram and PS the
+ -- source subprogram to which the postcondition applies. During
+ -- pre-analysis, CS is the scope of the subprogram declaration.
+
+ Prag : Node_Id;
+ -- During pre-analysis, Prag is the enclosing pragma node if any
+
+ begin
+ -- Find the proper enclosing scope
+
+ CS := Current_Scope;
+ while Present (CS) loop
+
+ -- Skip generated loops
+
+ if Ekind (CS) = E_Loop then
+ CS := Scope (CS);
+
+ -- Skip the special _Parent scope generated to capture references
+ -- to formals during the process of subprogram inlining.
+
+ elsif Ekind (CS) = E_Function
+ and then Chars (CS) = Name_uParent
+ then
+ CS := Scope (CS);
+ else
+ exit;
+ end if;
+ end loop;
+
+ PS := Scope (CS);
+
+ -- If the enclosing subprogram is always inlined, the enclosing
+ -- postcondition will not be propagated to the expanded call.
+
+ if not In_Spec_Expression
+ and then Has_Pragma_Inline_Always (PS)
+ and then Warn_On_Redundant_Constructs
+ then
+ Error_Msg_N
+ ("postconditions on inlined functions not enforced?r?", N);
+ end if;
+
+ -- If we are in the scope of a function and in Spec_Expression mode,
+ -- this is likely the prescan of the postcondition (or contract case,
+ -- or test case) pragma, and we just set the proper type. If there is
+ -- an error it will be caught when the real Analyze call is done.
+
+ if Ekind (CS) = E_Function
+ and then In_Spec_Expression
+ then
+ -- Check OK prefix
+
+ if Chars (CS) /= Chars (P) then
+ Error_Msg_Name_1 := Name_Result;
+
+ Error_Msg_NE
+ ("incorrect prefix for % attribute, expected &", P, CS);
+ Error_Attr;
+ end if;
+
+ -- Check in postcondition or Ensures clause of function
+
+ Prag := N;
+ while not Nkind_In (Prag, N_Pragma,
+ N_Function_Specification,
+ N_Subprogram_Body)
+ loop
+ Prag := Parent (Prag);
+ end loop;
+
+ if Nkind (Prag) /= N_Pragma then
+ Error_Attr
+ ("% attribute can only appear in postcondition of function",
+ P);
+
+ elsif Get_Pragma_Id (Prag) = Pragma_Contract_Case
+ or else
+ Get_Pragma_Id (Prag) = Pragma_Test_Case
+ then
+ declare
+ Arg_Ens : constant Node_Id :=
+ Get_Ensures_From_CTC_Pragma (Prag);
+ Arg : Node_Id;
+
+ begin
+ Arg := N;
+ while Arg /= Prag and Arg /= Arg_Ens loop
+ Arg := Parent (Arg);
+ end loop;
+
+ if Arg /= Arg_Ens then
+ if Get_Pragma_Id (Prag) = Pragma_Contract_Case then
+ Error_Attr
+ ("% attribute misplaced inside contract case", P);
+ else
+ Error_Attr
+ ("% attribute misplaced inside test case", P);
+ end if;
+ end if;
+ end;
+
+ elsif Get_Pragma_Id (Prag) /= Pragma_Postcondition then
+ Error_Attr
+ ("% attribute can only appear in postcondition of function",
+ P);
+ end if;
+
+ -- The attribute reference is a primary. If expressions follow,
+ -- the attribute reference is really an indexable object, so
+ -- rewrite and analyze as an indexed component.
+
+ if Present (E1) then
+ Rewrite (N,
+ Make_Indexed_Component (Loc,
+ Prefix =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Relocate_Node (Prefix (N)),
+ Attribute_Name => Name_Result),
+ Expressions => Expressions (N)));
+ Analyze (N);
+ return;
+ end if;
+
+ Set_Etype (N, Etype (CS));
+
+ -- If several functions with that name are visible,
+ -- the intended one is the current scope.
+
+ if Is_Overloaded (P) then
+ Set_Entity (P, CS);
+ Set_Is_Overloaded (P, False);
+ end if;
+
+ -- Body case, where we must be inside a generated _Postcondition
+ -- procedure, and the prefix must be on the scope stack, or else the
+ -- attribute use is definitely misplaced. The postcondition itself
+ -- may have generated transient scopes, and is not necessarily the
+ -- current one.
+
+ else
+ while Present (CS) and then CS /= Standard_Standard loop
+ if Chars (CS) = Name_uPostconditions then
+ exit;
+ else
+ CS := Scope (CS);
+ end if;
+ end loop;
+
+ PS := Scope (CS);
+
+ if Chars (CS) = Name_uPostconditions
+ and then Ekind (PS) = E_Function
+ then
+ -- Check OK prefix
+
+ if Nkind_In (P, N_Identifier, N_Operator_Symbol)
+ and then Chars (P) = Chars (PS)
+ then
+ null;
+
+ -- Within an instance, the prefix designates the local renaming
+ -- of the original generic.
+
+ elsif Is_Entity_Name (P)
+ and then Ekind (Entity (P)) = E_Function
+ and then Present (Alias (Entity (P)))
+ and then Chars (Alias (Entity (P))) = Chars (PS)
+ then
+ null;
+
+ else
+ Error_Msg_NE
+ ("incorrect prefix for % attribute, expected &", P, PS);
+ Error_Attr;
+ end if;
+
+ Rewrite (N, Make_Identifier (Sloc (N), Name_uResult));
+ Analyze_And_Resolve (N, Etype (PS));
+
+ else
+ Error_Attr
+ ("% attribute can only appear in postcondition of function",
+ 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);
+
+ -----------
+ -- 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);
+
+ ------------------
+ -- Same_Storage --
+ ------------------
+
+ when Attribute_Same_Storage =>
+ Check_Ada_2012_Attribute;
+ 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);
+
+ --------------------------
+ -- Scalar_Storage_Order --
+ --------------------------
+
+ when Attribute_Scalar_Storage_Order => Scalar_Storage_Order :
+ begin
+ Check_E0;
+ Check_Type;
+
+ if not Is_Record_Type (P_Type) or else Is_Array_Type (P_Type) then
+ Error_Attr_P
+ ("prefix of % attribute must be record or array type");
+ end if;
+
+ if Bytes_Big_Endian xor Reverse_Storage_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);
+ 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 => Size :
+ begin
+ 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;
+
+ else
+ Error_Attr_P ("invalid prefix for % attribute");
+ end if;
+
+ Check_Not_Incomplete_Type;
+ Check_Not_CPP_Type;
+ Set_Etype (N, Universal_Integer);
+ end Size;
+
+ -----------
+ -- Small --
+ -----------
+
+ when Attribute_Small =>
+ Check_E0;
+ Check_Real_Type;
+ Set_Etype (N, Universal_Real);
+
+ ------------------
+ -- Storage_Pool --
+ ------------------
+
+ when Attribute_Storage_Pool |
+ Attribute_Simple_Storage_Pool => Storage_Pool :
+ begin
+ 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_N ("cannot use % attribute for type with simple "
+ & "storage pool??", N);
+ Error_Msg_N
+ ("\Program_Error will be raised at run time??", 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;
+ end Storage_Pool;
+
+ ------------------
+ -- Storage_Size --
+ ------------------
+
+ when Attribute_Storage_Size => Storage_Size :
+ begin
+ 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;
+ end Storage_Size;
+
+ ------------------
+ -- 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 classwide");
+ 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_Restriction
+ ("attribute% is not allowed for type%", P);
+ end if;
+
+ Resolve (E1, P_Base_Type);
+ Set_Etype (N, P_Base_Type);
+
+ -- Nothing to do for real type case
+
+ if Is_Real_Type (P_Type) then
+ null;
+
+ -- If not modular type, test for overflow check required
+
+ else
+ if not Is_Modular_Integer_Type (P_Type)
+ and then not Range_Checks_Suppressed (P_Base_Type)
+ then
+ Enable_Range_Check (E1);
+ end if;
+ end if;
+
+ --------------------------------
+ -- System_Allocator_Alignment --
+ --------------------------------
+
+ when Attribute_System_Allocator_Alignment =>
+ Standard_Attribute (Ttypes.System_Allocator_Alignment);
+
+ ---------
+ -- Tag --
+ ---------
+
+ when Attribute_Tag => Tag :
+ begin
+ 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));
+ end 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);
+ end Target_Name;
+
+ ----------------
+ -- Terminated --
+ ----------------
+
+ when Attribute_Terminated =>
+ Check_E0;
+ Set_Etype (N, Standard_Boolean);
+ Check_Task_Prefix;
+
+ ----------------
+ -- To_Address --
+ ----------------
+
+ when Attribute_To_Address =>
+ Check_E1;
+ Analyze (P);
+
+ if Nkind (P) /= N_Identifier
+ or else Chars (P) /= Name_System
+ then
+ Error_Attr_P ("prefix of % attribute must be System");
+ end if;
+
+ Generate_Reference (RTE (RE_Address), P);
+ Analyze_And_Resolve (E1, Any_Integer);
+ Set_Etype (N, RTE (RE_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 =>
+ Check_E0;
+ Check_Type;
+
+ -- This processing belongs in Eval_Attribute ???
+
+ declare
+ function Type_Key return String_Id;
+ -- A very preliminary implementation. For now, a signature
+ -- consists of only the type name. This is clearly incomplete
+ -- (e.g., adding a new field to a record type should change the
+ -- type's Type_Key attribute).
+
+ --------------
+ -- Type_Key --
+ --------------
+
+ function Type_Key return String_Id is
+ Full_Name : constant String_Id :=
+ Fully_Qualified_Name_String (Entity (P));
+
+ begin
+ -- Copy all characters in Full_Name but the trailing NUL
+
+ Start_String;
+ for J in 1 .. String_Length (Full_Name) - 1 loop
+ Store_String_Char (Get_String_Char (Full_Name, Int (J)));
+ end loop;
+
+ Store_String_Chars ("'Type_Key");
+ return End_String;
+ end Type_Key;
+
+ begin
+ Rewrite (N, Make_String_Literal (Loc, Type_Key));
+ end;
+
+ Analyze_And_Resolve (N, Standard_String);
+
+ -----------------
+ -- UET_Address --
+ -----------------
+
+ when Attribute_UET_Address =>
+ Check_E0;
+ Check_Unit_Name (P);
+ Set_Etype (N, RTE (RE_Address));
+
+ -----------------------
+ -- Unbiased_Rounding --
+ -----------------------
+
+ when Attribute_Unbiased_Rounding =>
+ Check_Floating_Point_Type_1;
+ Set_Etype (N, P_Base_Type);
+ Resolve (E1, P_Base_Type);
+
+ ----------------------
+ -- Unchecked_Access --
+ ----------------------
+
+ when Attribute_Unchecked_Access =>
+ if Comes_From_Source (N) then
+ Check_Restriction (No_Unchecked_Access, N);
+ end if;
+
+ Analyze_Access_Attribute;
+
+ -------------------------
+ -- Unconstrained_Array --
+ -------------------------
+
+ when Attribute_Unconstrained_Array =>
+ Check_E0;
+ Check_Type;
+ Check_Not_Incomplete_Type;
+ Set_Etype (N, Standard_Boolean);
+
+ ------------------------------
+ -- Universal_Literal_String --
+ ------------------------------
+
+ -- This is a GNAT specific attribute whose prefix must be a named
+ -- number where the expression is either a single numeric literal,
+ -- or a numeric literal immediately preceded by a minus sign. The
+ -- result is equivalent to a string literal containing the text of
+ -- the literal as it appeared in the source program with a possible
+ -- leading minus sign.
+
+ when Attribute_Universal_Literal_String => Universal_Literal_String :
+ begin
+ Check_E0;
+
+ if not Is_Entity_Name (P)
+ or else Ekind (Entity (P)) not in Named_Kind
+ then
+ Error_Attr_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);
+ end;
+ end if;
+ end Universal_Literal_String;
+
+ -------------------------
+ -- Unrestricted_Access --
+ -------------------------
+
+ -- This is a GNAT specific attribute which is like Access except that
+ -- all scope checks and checks for aliased views are omitted.
+
+ when Attribute_Unrestricted_Access =>
+
+ -- If 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;
+
+ Analyze_Access_Attribute;
+
+ ------------
+ -- Update --
+ ------------
+
+ when Attribute_Update => Update : declare
+ Comps : Elist_Id := No_Elist;
+
+ procedure Check_Component_Reference
+ (Comp : Entity_Id;
+ Typ : Entity_Id);
+ -- Comp is a record component (possibly a discriminant) and Typ is a
+ -- record type. Determine whether Comp is a legal component of Typ.
+ -- Emit an error if Comp mentions a discriminant or is not a unique
+ -- component reference in the update aggregate.
+
+ -------------------------------
+ -- Check_Component_Reference --
+ -------------------------------
+
+ procedure Check_Component_Reference
+ (Comp : Entity_Id;
+ Typ : Entity_Id)
+ is
+ Comp_Name : constant Name_Id := Chars (Comp);
+
+ function Is_Duplicate_Component return Boolean;
+ -- Determine whether component Comp already appears in list Comps
+
+ ----------------------------
+ -- Is_Duplicate_Component --
+ ----------------------------
+
+ function Is_Duplicate_Component return Boolean is
+ Comp_Elmt : Elmt_Id;
+
+ begin
+ if Present (Comps) then
+ Comp_Elmt := First_Elmt (Comps);
+ while Present (Comp_Elmt) loop
+ if Chars (Node (Comp_Elmt)) = Comp_Name then
+ return True;
+ end if;
+
+ Next_Elmt (Comp_Elmt);
+ end loop;
+ end if;
+
+ return False;
+ end Is_Duplicate_Component;
+
+ -- Local variables
+
+ Comp_Or_Discr : Entity_Id;
+
+ -- Start of processing for Check_Component_Reference
+
+ 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 (Typ);
+ while Present (Comp_Or_Discr) loop
+ if Chars (Comp_Or_Discr) = Comp_Name then
+ exit;
+ end if;
+
+ Comp_Or_Discr := Next_Entity (Comp_Or_Discr);
+ end loop;
+
+ -- Diagnose possible erroneous references
+
+ 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 Is_Duplicate_Component then
+ Error_Msg_NE ("component & already updated", Comp, Comp);
+
+ -- Mark this component as processed
+
+ else
+ if No (Comps) then
+ Comps := New_Elmt_List;
+ end if;
+
+ Append_Elmt (Comp, Comps);
+ end if;
+ end if;
+
+ -- The update aggregate mentions an entity that does not belong to
+ -- the record type.
+
+ else
+ Error_Msg_NE
+ ("& is not a component of aggregate subtype", Comp, Comp);
+ end if;
+ end Check_Component_Reference;
+
+ -- Local variables
+
+ Assoc : Node_Id;
+ Comp : Node_Id;
+
+ -- Start of processing for Update
+
+ begin
+ S14_Attribute;
+ 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_Immutably_Limited_Type (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) Component legality for records
+
+ -- The remaining checks are performed on the expanded attribute
+
+ Assoc := First (Component_Associations (E1));
+ while Present (Assoc) loop
+ Comp := First (Choices (Assoc));
+ while Present (Comp) loop
+ if Nkind (Comp) = N_Others_Choice then
+ Error_Attr
+ ("others choice not allowed in attribute %", Comp);
+
+ elsif Is_Record_Type (P_Type) then
+ Check_Component_Reference (Comp, P_Type);
+ end if;
+
+ Next (Comp);
+ end loop;
+
+ Next (Assoc);
+ end loop;
+
+ -- The type of attribute Update is that of the prefix
+
+ Set_Etype (N, P_Type);
+ end Update;
+
+ ---------
+ -- Val --
+ ---------
+
+ when Attribute_Val => Val : declare
+ begin
+ 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_Restriction
+ ("attribute% is not allowed for type%", P);
+ end if;
+
+ Resolve (E1, Any_Integer);
+ Set_Etype (N, P_Base_Type);
+
+ -- Note, we need a range check in general, but we wait for the
+ -- Resolve call to do this, since we want to let Eval_Attribute
+ -- have a chance to find an static illegality first!
+ end Val;
+
+ -----------
+ -- Valid --
+ -----------
+
+ when Attribute_Valid =>
+ Check_E0;
+
+ -- Ignore check for object if we have a 'Valid reference generated
+ -- by the expanded code, since in some cases valid checks can occur
+ -- on items that are names, but are not objects (e.g. attributes).
+
+ if Comes_From_Source (N) then
+ Check_Object_Reference (P);
+ end if;
+
+ if not Is_Scalar_Type (P_Type) then
+ Error_Attr_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);
+
+ if No_Scalar_Parts (P_Type) then
+ Error_Attr_P ("??attribute % always True, no scalars to check");
+ end if;
+
+ Set_Etype (N, Standard_Boolean);
+
+ -----------
+ -- Value --
+ -----------
+
+ when Attribute_Value => Value :
+ begin
+ Check_SPARK_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;
+ end Value;
+
+ ----------------
+ -- Value_Size --
+ ----------------
+
+ when Attribute_Value_Size =>
+ Check_E0;
+ Check_Type;
+ Check_Not_Incomplete_Type;
+ Set_Etype (N, Universal_Integer);
+
+ -------------
+ -- Version --
+ -------------
+
+ when Attribute_Version =>
+ Check_E0;
+ Check_Program_Unit;
+ Set_Etype (N, RTE (RE_Version_String));
+
+ ------------------
+ -- Wchar_T_Size --
+ ------------------
+
+ when Attribute_Wchar_T_Size =>
+ Standard_Attribute (Interfaces_Wchar_T_Size);
+
+ ----------------
+ -- Wide_Image --
+ ----------------
+
+ when Attribute_Wide_Image => Wide_Image :
+ begin
+ Check_SPARK_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;
+ end Wide_Image;
+
+ ---------------------
+ -- Wide_Wide_Image --
+ ---------------------
+
+ when Attribute_Wide_Wide_Image => Wide_Wide_Image :
+ begin
+ Check_Scalar_Type;
+ Set_Etype (N, Standard_Wide_Wide_String);
+ Check_E1;
+ Resolve (E1, P_Base_Type);
+ Validate_Non_Static_Attribute_Function_Call;
+ end Wide_Wide_Image;
+
+ ----------------
+ -- Wide_Value --
+ ----------------
+
+ when Attribute_Wide_Value => Wide_Value :
+ begin
+ Check_SPARK_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;
+ end Wide_Value;
+
+ ---------------------
+ -- Wide_Wide_Value --
+ ---------------------
+
+ when Attribute_Wide_Wide_Value => Wide_Wide_Value :
+ begin
+ Check_E1;
+ Check_Scalar_Type;
+
+ -- Set Etype before resolving expression because expansion
+ -- of expression may require enclosing type.
+
+ Set_Etype (N, P_Type);
+ Validate_Non_Static_Attribute_Function_Call;
+ end Wide_Wide_Value;
+
+ ---------------------
+ -- 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_Restriction_On_Attribute;
+ Check_E0;
+ Check_Scalar_Type;
+ Set_Etype (N, Universal_Integer);
+
+ -----------
+ -- Width --
+ -----------
+
+ when Attribute_Width =>
+ Check_SPARK_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;
+
+ -- 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
+
+ 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 Is_VAX_Float (Typ : Entity_Id) return Boolean;
+ -- Determine whether Typ denotes a VAX floating point type
+
+ 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;
+
+ ------------------
+ -- Is_VAX_Float --
+ ------------------
+
+ function Is_VAX_Float (Typ : Entity_Id) return Boolean is
+ begin
+ return
+ Is_Floating_Point_Type (Typ)
+ and then
+ (Float_Format = 'V' or else Float_Rep (Typ) = VAX_Native);
+ end Is_VAX_Float;
+
+ --------------
+ -- 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 not Is_Static_Subtype (Ityp) then
+ Static := False;
+ 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
+ -- 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, and testing expander active
+ -- is as easy way of doing this as any.
+
+ if Expander_Active 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;
+
+ -- 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 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)), False);
+ 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;
+
+ -- At this stage P_Entity is the entity to which the attribute
+ -- is to be applied. This is usually simply the entity of the
+ -- prefix, except in some cases of attributes for objects, where
+ -- as described above, we apply the attribute to the object type.
+
+ -- First foldable possibility is a scalar or array type (RM 4.9(7))
+ -- that is not generic (generic types are eliminated by RM 4.9(25)).
+ -- Note we allow non-static non-generic types at this stage as further
+ -- described below.
+
+ if Is_Type (P_Entity)
+ and then (Is_Scalar_Type (P_Entity) or Is_Array_Type (P_Entity))
+ and then (not Is_Generic_Type (P_Entity))
+ then
+ P_Type := P_Entity;
+
+ -- Second foldable possibility is an array object (RM 4.9(8))
+
+ elsif (Ekind (P_Entity) = E_Variable
+ or else
+ Ekind (P_Entity) = E_Constant)
+ and then Is_Array_Type (Etype (P_Entity))
+ and then (not Is_Generic_Type (Etype (P_Entity)))
+ then
+ P_Type := Etype (P_Entity);
+
+ -- If the entity is an array constant with an unconstrained nominal
+ -- subtype then get the type from the initial value. If the value has
+ -- been expanded into assignments, 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
+ Static := Is_OK_Static_Subtype (P_Type);
+
+ -- Array case. We enforce the constrained requirement of (RM 4.9(7-8))
+ -- since we can't do anything with unconstrained arrays. In addition,
+ -- only the First, Last and Length attributes are possibly static.
+
+ -- 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;
+
+ 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);
+
+ declare
+ N : Node_Id;
+
+ begin
+ N := 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);
+ end if;
+
+ while Present (N) loop
+ Static := Static and then Is_Static_Subtype (Etype (N));
+
+ -- If however the index type is generic, or derived from
+ -- one, attributes cannot be folded.
+
+ if Is_Generic_Type (Root_Type (Etype (N)))
+ and then Id /= Attribute_Component_Size
+ then
+ return;
+ end if;
+
+ Next_Index (N);
+ end loop;
+ end;
+ end if;
+
+ -- Check any expressions that are present. Note that these expressions,
+ -- depending on the particular attribute type, are either part of the
+ -- attribute designator, or they are arguments in a case where the
+ -- attribute reference returns a function. In the latter case, the
+ -- rule in (RM 4.9(22)) applies and in particular requires the type
+ -- of the expressions to be scalar in order for the attribute to be
+ -- considered to be static.
+
+ declare
+ E : Node_Id;
+
+ begin
+ E := E1;
+ while Present (E) loop
+
+ -- If expression is not static, then the attribute reference
+ -- result certainly cannot be static.
+
+ if not Is_Static_Expression (E) then
+ Static := False;
+ 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
+ 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_Is_Static_Expression (N, Static);
+ return;
+ end if;
+
+ -- At this point we have a potentially foldable attribute reference.
+ -- If Static is set, then the attribute reference definitely obeys
+ -- the requirements in (RM 4.9(7,8,22)), and it definitely can be
+ -- folded. If Static is not set, then the attribute may or may not
+ -- be foldable, and the individual attribute processing routines
+ -- test Static as required in cases where it makes a difference.
+
+ -- 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_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), True);
+
+ ---------------
+ -- 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), Is_Discrete_Type (P_TypeA));
+ end if;
+ end Alignment_Block;
+
+ ---------------
+ -- AST_Entry --
+ ---------------
+
+ -- Can only be folded in No_Ast_Handler case
+
+ when Attribute_AST_Entry =>
+ if not Is_AST_Entry (P_Entity) then
+ Rewrite (N,
+ New_Occurrence_Of (RTE (RE_No_AST_Handler), Loc));
+ else
+ null;
+ end if;
+
+ -----------------------------
+ -- 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;
+ 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), False);
+ 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 =>
+ 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 (not Is_Indefinite_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))), True);
+
+ ---------------------
+ -- Descriptor_Size --
+ ---------------------
+
+ when Attribute_Descriptor_Size =>
+ null;
+
+ ------------
+ -- Digits --
+ ------------
+
+ when Attribute_Digits =>
+ Fold_Uint (N, Digits_Value (P_Type), True);
+
+ ----------
+ -- Emax --
+ ----------
+
+ when Attribute_Emax =>
+
+ -- Ada 83 attribute is defined as (RM83 3.5.8)
+
+ -- T'Emax = 4 * T'Mantissa
+
+ Fold_Uint (N, 4 * Mantissa, True);
+
+ --------------
+ -- Enum_Rep --
+ --------------
+
+ when Attribute_Enum_Rep =>
+
+ -- 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 (E1)), 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 (E1), Static);
+ end if;
+
+ --------------
+ -- 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);
+
+ -----------
+ -- First --
+ -----------
+
+ when Attribute_First => First_Attr :
+ begin
+ Set_Bounds;
+
+ if Compile_Time_Known_Value (Lo_Bound) then
+ if Is_Real_Type (P_Type) then
+ Fold_Ureal (N, Expr_Value_R (Lo_Bound), Static);
+ else
+ Fold_Uint (N, Expr_Value (Lo_Bound), Static);
+ end if;
+
+ -- Replace VAX Float_Type'First with a reference to the temporary
+ -- which represents the low bound of the type. This transformation
+ -- is needed since the back end cannot evaluate 'First on VAX.
+
+ elsif Is_VAX_Float (P_Type)
+ and then Nkind (Lo_Bound) = N_Identifier
+ then
+ Rewrite (N, New_Reference_To (Entity (Lo_Bound), Sloc (N)));
+ Analyze (N);
+
+ else
+ Check_Concurrent_Discriminant (Lo_Bound);
+ end if;
+ end First_Attr;
+
+ -----------------
+ -- First_Valid --
+ -----------------
+
+ when Attribute_First_Valid => First_Valid :
+ begin
+ if Has_Predicates (P_Type)
+ and then Present (Static_Predicate (P_Type))
+ then
+ declare
+ FirstN : constant Node_Id := First (Static_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;
+ end First_Valid;
+
+ -----------------
+ -- 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_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;
+
+ ---------
+ -- Img --
+ ---------
+
+ -- Img is a scalar attribute, but is never static, because it is
+ -- not a static function (having a non-scalar argument (RM 4.9(22))
+
+ when Attribute_Img =>
+ null;
+
+ -------------------
+ -- Integer_Value --
+ -------------------
+
+ -- 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;
+ end Lock_Free;
+
+ ----------
+ -- Last --
+ ----------
+
+ when Attribute_Last => Last_Attr :
+ begin
+ Set_Bounds;
+
+ if Compile_Time_Known_Value (Hi_Bound) then
+ if Is_Real_Type (P_Type) then
+ Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static);
+ else
+ Fold_Uint (N, Expr_Value (Hi_Bound), Static);
+ end if;
+
+ -- Replace VAX Float_Type'Last with a reference to the temporary
+ -- which represents the high bound of the type. This transformation
+ -- is needed since the back end cannot evaluate 'Last on VAX.
+
+ elsif Is_VAX_Float (P_Type)
+ and then Nkind (Hi_Bound) = N_Identifier
+ then
+ Rewrite (N, New_Reference_To (Entity (Hi_Bound), Sloc (N)));
+ Analyze (N);
+
+ else
+ Check_Concurrent_Discriminant (Hi_Bound);
+ end if;
+ end Last_Attr;
+
+ ----------------
+ -- Last_Valid --
+ ----------------
+
+ when Attribute_Last_Valid => Last_Valid :
+ begin
+ if Has_Predicates (P_Type)
+ and then Present (Static_Predicate (P_Type))
+ then
+ declare
+ LastN : constant Node_Id := Last (Static_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;
+ end Last_Valid;
+
+ ------------------
+ -- 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))),
+ True);
+ 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, False);
+
+ when GT =>
+ Fold_Uint (N, Uint_0, False);
+
+ when LT =>
+ if Diff /= No_Uint then
+ Fold_Uint (N, Diff + 1, False);
+ 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, True);
+
+ -- Floating point case
+
+ else
+ Fold_Uint (N,
+ UI_From_Int (Boolean'Pos (Machine_Overflows_On_Target)),
+ True);
+ 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, True);
+ else
+ Fold_Uint (N, Uint_2, True);
+ end if;
+
+ -- All floating-point type always have radix 2
+
+ else
+ Fold_Uint (N, Uint_2, True);
+ 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, True);
+
+ -- Else yield proper floating-point result
+
+ else
+ Fold_Uint
+ (N, UI_From_Int (Boolean'Pos (Machine_Rounds_On_Target)), True);
+ 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), True);
+ 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, True);
+ 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, True);
+ end if;
+
+ ---------
+ -- Max --
+ ---------
+
+ when Attribute_Max => Max :
+ begin
+ if Is_Real_Type (P_Type) then
+ Fold_Ureal
+ (N, UR_Max (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
+ else
+ Fold_Uint (N, UI_Max (Expr_Value (E1), Expr_Value (E2)), Static);
+ end if;
+ end Max;
+
+ ----------------------------------
+ -- 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 =>
+ 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_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 =>
+ declare
+ Val : Int;
+ Formal : Entity_Id;
+ Mech : Mechanism_Type;
+
+ begin
+ if No (E1) then
+ Mech := Mechanism (P_Entity);
+
+ else
+ Val := UI_To_Int (Expr_Value (E1));
+
+ Formal := First_Formal (P_Entity);
+ for J in 1 .. Val - 1 loop
+ Next_Formal (Formal);
+ end loop;
+ Mech := Mechanism (Formal);
+ end if;
+
+ if Mech < 0 then
+ Fold_Uint (N, UI_From_Int (Int (-Mech)), True);
+ end if;
+ end;
+
+ ---------
+ -- Min --
+ ---------
+
+ when Attribute_Min => Min :
+ begin
+ if Is_Real_Type (P_Type) then
+ Fold_Ureal
+ (N, UR_Min (Expr_Value_R (E1), Expr_Value_R (E2)), Static);
+ else
+ Fold_Uint
+ (N, UI_Min (Expr_Value (E1), Expr_Value (E2)), Static);
+ end if;
+ end Min;
+
+ ---------
+ -- 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), True);
+
+ --------------------
+ -- 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), True);
+ 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, True);
+
+ ---------
+ -- Pos --
+ ---------
+
+ when Attribute_Pos =>
+ Fold_Uint (N, Expr_Value (E1), True);
+
+ ----------
+ -- Pred --
+ ----------
+
+ when Attribute_Pred => Pred :
+ begin
+ -- 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;
+ end Pred;
+
+ -----------
+ -- Range --
+ -----------
+
+ -- No processing required, because by this stage, Range has been
+ -- replaced by First .. Last, so this branch can never be taken.
+
+ when Attribute_Range =>
+ raise Program_Error;
+
+ ------------------
+ -- Range_Length --
+ ------------------
+
+ when Attribute_Range_Length =>
+ Set_Bounds;
+
+ -- 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.
+
+ 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, False);
+
+ when GT =>
+ Fold_Uint (N, Uint_0, False);
+
+ when LT =>
+ if Diff /= No_Uint then
+ Fold_Uint (N, Diff + 1, False);
+ end if;
+
+ when others =>
+ null;
+ end case;
+ end;
+
+ ---------
+ -- Ref --
+ ---------
+
+ when Attribute_Ref =>
+ Fold_Uint (N, Expr_Value (E1), True);
+
+ ---------------
+ -- 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;
+
+ -----------
+ -- 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;
+
+ ------------------
+ -- Same_Storage --
+ ------------------
+
+ when Attribute_Same_Storage =>
+ null;
+
+ -----------
+ -- Scale --
+ -----------
+
+ when Attribute_Scale =>
+ Fold_Uint (N, Scale_Value (P_Type), True);
+
+ -------------
+ -- 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.
+
+ when Attribute_Size | Attribute_VADS_Size => Size : declare
+ P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
+
+ begin
+ if RM_Size (P_TypeA) /= Uint_0 then
+
+ -- VADS_Size case
+
+ if Id = Attribute_VADS_Size or else Use_VADS_Size then
+ declare
+ S : constant Node_Id := Size_Clause (P_TypeA);
+
+ begin
+ -- If a size clause applies, then use the size from it.
+ -- This is one of the rare cases where we can use the
+ -- Size_Clause field for a subtype when Has_Size_Clause
+ -- is False. Consider:
+
+ -- type x is range 1 .. 64;
+ -- for x'size use 12;
+ -- subtype y is x range 0 .. 3;
+
+ -- Here y has a size clause inherited from x, but normally
+ -- it does not apply, and y'size is 2. However, y'VADS_Size
+ -- is indeed 12 and not 2.
+
+ if Present (S)
+ and then Is_OK_Static_Expression (Expression (S))
+ then
+ Fold_Uint (N, Expr_Value (Expression (S)), True);
+
+ -- 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), True);
+ end if;
+ end;
+
+ -- Normal case (Size) in which case we want the RM_Size
+
+ else
+ Fold_Uint (N,
+ RM_Size (P_TypeA),
+ Static and then Is_Discrete_Type (P_TypeA));
+ end if;
+ end if;
+ end Size;
+
+ -----------
+ -- Small --
+ -----------
+
+ when Attribute_Small =>
+
+ -- The floating-point case is present only for Ada 83 compatibility.
+ -- Note that strictly this is an illegal addition, since we are
+ -- extending an Ada 95 defined attribute, but we anticipate an
+ -- ARG ruling that will permit this.
+
+ if Is_Floating_Point_Type (P_Type) then
+
+ -- Ada 83 attribute is defined as (RM83 3.5.8)
+
+ -- T'Small = 2.0**(-T'Emax - 1)
+
+ -- where
+
+ -- T'Emax = 4 * T'Mantissa
+
+ Fold_Ureal (N, Ureal_2 ** ((-(4 * Mantissa)) - 1), 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 => Succ :
+ begin
+ -- 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;
+ end Succ;
+
+ ----------------
+ -- 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_Descendent_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_Enumeration_Type (Typ) then
+ Id := RE_Type_Class_Enumeration;
+
+ elsif Is_Task_Type (Typ) then
+ Id := RE_Type_Class_Task;
+
+ -- We treat protected types like task types. It would make more
+ -- sense to have another enumeration value, but after all the
+ -- whole point of this feature is to be exactly DEC compatible,
+ -- and changing the type Type_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;
+ end Unconstrained_Array;
+
+ -- Attribute Update is never static
+
+ ------------
+ -- Update --
+ ------------
+
+ when Attribute_Update =>
+ null;
+
+ ---------------
+ -- VADS_Size --
+ ---------------
+
+ -- Processing is shared with Size
+
+ ---------
+ -- Val --
+ ---------
+
+ when Attribute_Val => Val :
+ begin
+ 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;
+ end Val;
+
+ ----------------
+ -- Value_Size --
+ ----------------
+
+ -- The Value_Size attribute for a type returns the RM size of the
+ -- type. This an always be folded for scalar types, and can also
+ -- be folded for non-scalar types if the size is set.
+
+ when Attribute_Value_Size => Value_Size : declare
+ P_TypeA : constant Entity_Id := Underlying_Type (P_Type);
+ begin
+ if RM_Size (P_TypeA) /= Uint_0 then
+ Fold_Uint (N, RM_Size (P_TypeA), True);
+ 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 => Width :
+ begin
+ 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, True);
+
+ 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), True);
+ 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, True);
+
+ -- 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),
+ True);
+ 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 | HT | LF | VT | FF | CR |
+ SO | SI | EM | FS | GS | RS |
+ US | RI | MW | ST | PM
+ => Wt := 2;
+
+ when NUL | SOH | STX | ETX | EOT |
+ ENQ | ACK | BEL | DLE | DC1 |
+ DC2 | DC3 | DC4 | NAK | SYN |
+ ETB | CAN | SUB | ESC | DEL |
+ BPH | NBH | NEL | SSA | ESA |
+ HTS | HTJ | VTS | PLD | PLU |
+ SS2 | SS3 | DCS | PU1 | PU2 |
+ STS | CCH | SPA | EPA | SOS |
+ SCI | CSI | OSC | APC
+ => Wt := 3;
+
+ when Space .. Tilde |
+ No_Break_Space .. LC_Y_Diaeresis
+ =>
+ -- 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 accomodates 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), True);
+ end;
+ end if;
+ end if;
+ end Width;
+
+ -- 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.
+
+ 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_Elaborated |
+ Attribute_Elab_Body |
+ Attribute_Elab_Spec |
+ Attribute_Elab_Subp_Body |
+ Attribute_Enabled |
+ Attribute_External_Tag |
+ Attribute_Fast_Math |
+ Attribute_First_Bit |
+ Attribute_Input |
+ Attribute_Last_Bit |
+ 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_UET_Address |
+ 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.
+
+ ---------------------------
+ -- 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_F
+ ("??non-local pointer cannot point to local object", P);
+ Error_Msg_F
+ ("\??Program_Error will be raised at run time", 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;
+
+ -- 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 =>
+
+ Access_Attribute :
+ begin
+ if Is_Variable (P) then
+ Note_Possible_Modification (P, Sure => False);
+ end if;
+
+ -- The following comes from a query by Adam Beneschan, 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;
+
+ if Is_Entity_Name (P) then
+ if Is_Overloaded (P) then
+ Get_First_Interp (P, Index, It);
+ while Present (It.Nam) loop
+ if Type_Conformant (Designated_Type (Typ), It.Nam) then
+ Set_Entity (P, It.Nam);
+
+ -- The prefix is definitely NOT overloaded anymore at
+ -- this point, so we reset the Is_Overloaded flag to
+ -- avoid any confusion when reanalyzing the node.
+
+ Set_Is_Overloaded (P, False);
+ 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, it is frozen by this
+ -- reference:
+
+ -- If it is a type, there is nothing to resolve.
+ -- If it is an object, complete its resolution.
+
+ elsif Is_Overloadable (Entity (P)) then
+
+ -- Avoid insertion of freeze actions in spec expression mode
+
+ if not In_Spec_Expression then
+ Freeze_Before (N, Entity (P));
+ end if;
+
+ elsif Is_Type (Entity (P)) then
+ null;
+ else
+ Resolve (P);
+ end if;
+
+ 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 Convention (Entity (P)) = Convention_Intrinsic then
+ if Ekind (Entity (P)) = E_Enumeration_Literal then
+ Error_Msg_F
+ ("prefix of % attribute cannot be enumeration literal",
+ P);
+ else
+ Error_Msg_F
+ ("prefix of % attribute cannot be intrinsic", P);
+ end if;
+
+ Set_Etype (N, Any_Type);
+ end if;
+
+ -- Assignments, return statements, components of aggregates,
+ -- generic instantiations will require convention checks if
+ -- the type is an access to subprogram. Given that there will
+ -- also be accessibility checks on those, this is where the
+ -- checks can eventually be centralized ???
+
+ if Ekind_In (Btyp, E_Access_Subprogram_Type,
+ E_Anonymous_Access_Subprogram_Type,
+ E_Access_Protected_Subprogram_Type,
+ E_Anonymous_Access_Protected_Subprogram_Type)
+ then
+ -- Deal with convention mismatch
+
+ if Convention (Designated_Type (Btyp)) /=
+ Convention (Entity (P))
+ then
+ Error_Msg_FE
+ ("subprogram & has wrong convention", P, Entity (P));
+ Error_Msg_FE
+ ("\does not match convention of access type &",
+ P, Btyp);
+
+ if 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 originally 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 case, 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.
+
+ -- Note that we relax this check in CodePeer mode for
+ -- compatibility with legacy code, since CodePeer is an
+ -- Ada source code analyzer, not a strict compiler.
+ -- ??? Note that a better approach would be to have a
+ -- separate switch to relax this rule, and enable this
+ -- switch in CodePeer mode.
+
+ elsif Attr_Id = Attribute_Access
+ and then not CodePeer_Mode
+ 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. 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 Enclosing_Generic_Unit (Entity (P)) /=
+ Enclosing_Generic_Unit (Root_Type (Btyp))
+ 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);
+
+ 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_With_Type (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.
+
+ if In_Instance_Body then
+ Error_Msg_F
+ ("??non-local pointer cannot point to local object", P);
+ Error_Msg_F
+ ("\??Program_Error will be raised at run time", 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 Effectively_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
+ Object_Access_Level (P) > Deepest_Type_Access_Level (Btyp)
+ and then Ekind (Btyp) = E_General_Access_Type
+ 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;
+
+ if Is_Entity_Name (P) then
+ Set_Address_Taken (Entity (P));
+ end if;
+ end Access_Attribute;
+
+ -------------
+ -- 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 =>
+ Address_Attribute : begin
+
+ -- 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;
+ end Address_Attribute;
+
+ ---------------
+ -- AST_Entry --
+ ---------------
+
+ -- Prefix of the AST_Entry attribute is an entry name which must
+ -- not be resolved, since this is definitely not an entry call.
+
+ when Attribute_AST_Entry =>
+ null;
+
+ ------------------
+ -- Body_Version --
+ ------------------
+
+ -- Prefix of Body_Version attribute can be a subprogram name which
+ -- must not be resolved, since this is not a call.
+
+ when Attribute_Body_Version =>
+ null;
+
+ ------------
+ -- Caller --
+ ------------
+
+ -- Prefix of Caller attribute is an entry name which must not
+ -- be resolved, since this is definitely not an entry call.
+
+ when Attribute_Caller =>
+ null;
+
+ ------------------
+ -- Code_Address --
+ ------------------
+
+ -- Shares processing with Address attribute
+
+ -----------
+ -- Count --
+ -----------
+
+ -- 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
+ LB : Node_Id;
+ HB : Node_Id;
+ Dims : List_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;
+
+ -----------------
+ -- UET_Address --
+ -----------------
+
+ -- Prefix must not be resolved in this case, since it is not a
+ -- real entity reference. No action of any kind is require!
+
+ when Attribute_UET_Address =>
+ return;
+
+ ----------------------
+ -- Unchecked_Access --
+ ----------------------
+
+ -- Processing is shared with Access
+
+ -------------------------
+ -- Unrestricted_Access --
+ -------------------------
+
+ -- Processing is shared with Access
+
+ ---------
+ -- Val --
+ ---------
+
+ -- Apply range check. Note that we did not do this during the
+ -- analysis phase, since we wanted Eval_Attribute to have a
+ -- chance at finding an illegal out of range value.
+
+ when Attribute_Val =>
+
+ -- Note that we do our own Eval_Attribute call here rather than
+ -- use the common one, because we need to do processing after
+ -- the call, as per above comment.
+
+ Eval_Attribute (N);
+
+ -- Eval_Attribute may replace the node with a raise CE, or
+ -- fold it to a constant. Obviously we only apply a scalar
+ -- range check if this did not happen!
+
+ if Nkind (N) = N_Attribute_Reference
+ and then Attribute_Name (N) = Name_Val
+ then
+ Apply_Scalar_Range_Check (First (Expressions (N)), Btyp);
+ end if;
+
+ return;
+
+ -------------
+ -- Version --
+ -------------
+
+ -- Prefix of Version attribute can be a subprogram name which
+ -- must not be resolved, since this is not a call.
+
+ when Attribute_Version =>
+ null;
+
+ ----------------------
+ -- Other Attributes --
+ ----------------------
+
+ -- For other attributes, resolve prefix unless it is a type. If
+ -- the attribute reference itself is a type name ('Base and 'Class)
+ -- then this is only legal within a task or protected record.
+
+ when others =>
+ if not Is_Entity_Name (P)
+ or else not Is_Type (Entity (P))
+ then
+ Resolve (P);
+ 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.
+
+ Freeze_Expression (P);
+
+ -- Finally perform static evaluation on the attribute reference
+
+ Analyze_Dimension (N);
+ Eval_Attribute (N);
+ end Resolve_Attribute;
+
+ --------------------------------
+ -- 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;