diff options
Diffstat (limited to 'gcc-4.2.1/gcc/ada/sem_attr.adb')
| -rw-r--r-- | gcc-4.2.1/gcc/ada/sem_attr.adb | 7898 |
1 files changed, 7898 insertions, 0 deletions
diff --git a/gcc-4.2.1/gcc/ada/sem_attr.adb b/gcc-4.2.1/gcc/ada/sem_attr.adb new file mode 100644 index 000000000..1a7288367 --- /dev/null +++ b/gcc-4.2.1/gcc/ada/sem_attr.adb @@ -0,0 +1,7898 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ A T T R -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2006, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 2, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, USA. -- +-- -- +-- 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 Checks; use Checks; +with Einfo; use Einfo; +with Errout; use Errout; +with Eval_Fat; +with Exp_Util; use Exp_Util; +with Expander; use Expander; +with Freeze; use Freeze; +with Lib; use Lib; +with Lib.Xref; use Lib.Xref; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sdefault; use Sdefault; +with Sem; use Sem; +with Sem_Cat; use Sem_Cat; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch8; use Sem_Ch8; +with Sem_Dist; use Sem_Dist; +with Sem_Eval; use Sem_Eval; +with Sem_Res; use Sem_Res; +with Sem_Type; use Sem_Type; +with Sem_Util; use Sem_Util; +with Stand; use Stand; +with Sinfo; use Sinfo; +with Sinput; use Sinput; +with Stringt; use Stringt; +with Targparm; use Targparm; +with Ttypes; use Ttypes; +with Ttypef; use Ttypef; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Urealp; use Urealp; + +package body Sem_Attr is + + True_Value : constant Uint := Uint_1; + False_Value : constant Uint := Uint_0; + -- Synonyms to be used when these constants are used as Boolean values + + Bad_Attribute : exception; + -- Exception raised if an error is detected during attribute processing, + -- used so that we can abandon the processing so we don't run into + -- trouble with cascaded errors. + + -- The following array is the list of attributes defined in the Ada 83 RM + + Attribute_83 : 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); + + ----------------------- + -- 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 Check_Array_Or_Scalar_Type; + -- Common procedure used by First, Last, Range attribute to check + -- that the prefix is a constrained array or scalar type, or a name + -- of an array object, and that an argument appears only if appropriate + -- (i.e. only in the array case). + + procedure Check_Array_Type; + -- Common semantic checks for all array attributes. Checks that the + -- prefix is a constrained array type or the name of an array object. + -- The error message for non-arrays is specialized appropriately. + + procedure Check_Asm_Attribute; + -- Common semantic checks for Asm_Input and Asm_Output attributes + + procedure Check_Component; + -- Common processing for Bit_Position, First_Bit, Last_Bit, and + -- Position. Checks prefix is an appropriate selected component. + + procedure Check_Decimal_Fixed_Point_Type; + -- Check that prefix of attribute N is a decimal fixed-point type + + procedure Check_Dereference; + -- If the prefix of attribute is an object of an access type, then + -- introduce an explicit deference, and adjust P_Type accordingly. + + procedure Check_Discrete_Type; + -- Verify that prefix of attribute N is a discrete type + + procedure Check_E0; + -- Check that no attribute arguments are present + + procedure Check_Either_E0_Or_E1; + -- Check that there are zero or one attribute arguments present + + procedure Check_E1; + -- Check that exactly one attribute argument is present + + procedure Check_E2; + -- Check that two attribute arguments are present + + procedure Check_Enum_Image; + -- If the prefix type is an enumeration type, set all its literals + -- as referenced, since the image function could possibly end up + -- referencing any of the literals indirectly. + + procedure Check_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, Has_Access_Values, + -- and Has_Discriminants + + procedure Check_Integer_Type; + -- Verify that prefix of attribute N is an integer type + + procedure Check_Library_Unit; + -- Verify that prefix of attribute N is a library unit + + procedure Check_Modular_Integer_Type; + -- Verify that prefix of attribute N is a modular integer type + + procedure Check_Not_Incomplete_Type; + -- Check that P (the prefix of the attribute) is not an incomplete + -- type or a private type for which no full view has been given. + + procedure Check_Object_Reference (P : Node_Id); + -- Check that P (the prefix of the attribute) is an object reference + + procedure Check_Program_Unit; + -- Verify that prefix of attribute N is a program unit + + procedure Check_Real_Type; + -- Verify that prefix of attribute N is fixed or float type + + procedure Check_Scalar_Type; + -- Verify that prefix of attribute N is a scalar type + + procedure Check_Standard_Prefix; + -- Verify that prefix of attribute N is package Standard + + procedure Check_Stream_Attribute (Nam : 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_Task_Prefix; + -- Verify that prefix of attribute N is a task or task type + + procedure Check_Type; + -- Verify that the prefix of attribute N is a type + + procedure Check_Unit_Name (Nod : Node_Id); + -- Check that Nod is of the form of a library unit name, i.e that + -- it is an identifier, or a selected component whose prefix is + -- itself of the form of a library unit name. Note that this is + -- quite different from Check_Program_Unit, since it only checks + -- the syntactic form of the name, not the semantic identity. This + -- is because it is used with attributes (Elab_Body, Elab_Spec, and + -- UET_Address) which can refer to non-visible unit. + + procedure Error_Attr (Msg : String; Error_Node : Node_Id); + pragma No_Return (Error_Attr); + 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 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 it the + -- node itself. The result is stored in Acc_Type. + + ------------------------------ + -- Build_Access_Object_Type -- + ------------------------------ + + function Build_Access_Object_Type (DT : Entity_Id) return Entity_Id is + Typ : Entity_Id; + + begin + if Aname = Name_Unrestricted_Access then + Typ := + New_Internal_Entity + (E_Allocator_Type, Current_Scope, Loc, 'A'); + else + Typ := + New_Internal_Entity + (E_Access_Attribute_Type, Current_Scope, Loc, 'A'); + end if; + + Set_Etype (Typ, Typ); + Init_Size_Align (Typ); + Set_Is_Itype (Typ); + Set_Associated_Node_For_Itype (Typ, N); + Set_Directly_Designated_Type (Typ, DT); + return Typ; + end Build_Access_Object_Type; + + ---------------------------------- + -- Build_Access_Subprogram_Type -- + ---------------------------------- + + procedure Build_Access_Subprogram_Type (P : Node_Id) is + Index : Interp_Index; + It : Interp; + + function Get_Kind (E : Entity_Id) return Entity_Kind; + -- Distinguish between access to regular/protected subprograms + + -------------- + -- 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. + + Set_Etype (N, Any_Type); + + if not Is_Overloaded (P) then + if not Is_Intrinsic_Subprogram (Entity (P)) then + Acc_Type := + New_Internal_Entity + (Get_Kind (Entity (P)), Current_Scope, Loc, 'A'); + Set_Etype (Acc_Type, Acc_Type); + Set_Directly_Designated_Type (Acc_Type, Entity (P)); + Set_Etype (N, Acc_Type); + end if; + + else + Get_First_Interp (P, Index, It); + while Present (It.Nam) loop + if not Is_Intrinsic_Subprogram (It.Nam) then + Acc_Type := + New_Internal_Entity + (Get_Kind (It.Nam), Current_Scope, Loc, 'A'); + Set_Etype (Acc_Type, Acc_Type); + Set_Directly_Designated_Type (Acc_Type, It.Nam); + Add_One_Interp (N, Acc_Type, Acc_Type); + end if; + + Get_Next_Interp (Index, It); + end loop; + end if; + + if Etype (N) = Any_Type then + Error_Attr ("prefix of % attribute cannot be intrinsic", P); + end if; + end Build_Access_Subprogram_Type; + + -- Start of processing for Analyze_Access_Attribute + + begin + Check_E0; + + if Nkind (P) = N_Character_Literal then + Error_Attr + ("prefix of % attribute cannot be enumeration literal", P); + end if; + + -- Case of access to subprogram + + if Is_Entity_Name (P) + and then Is_Overloadable (Entity (P)) + then + -- Not allowed for nested subprograms if No_Implicit_Dynamic_Code + -- restriction set (since in general a trampoline is required). + + if not Is_Library_Level_Entity (Entity (P)) then + Check_Restriction (No_Implicit_Dynamic_Code, P); + end if; + + if Is_Always_Inlined (Entity (P)) then + Error_Attr + ("prefix of % attribute cannot be Inline_Always subprogram", + P); + end if; + + -- Build the appropriate subprogram type + + Build_Access_Subprogram_Type (P); + + -- For unrestricted access, kill current values, since this + -- attribute allows a reference to a local subprogram that + -- could modify local variables to be passed out of scope + + if Aname = Name_Unrestricted_Access then + Kill_Current_Values; + 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 ("prefix of % attribute must be subprogram", P); + end if; + + Build_Access_Subprogram_Type (Selector_Name (P)); + return; + end if; + + -- Deal with incorrect reference to a type, but note that some + -- accesses are allowed (references to the current type instance). + + if Is_Entity_Name (P) then + 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_N + ("current instance prefix must be a direct name", P); + end if; + + -- If a current instance attribute appears within a + -- a component constraint it must appear alone; other + -- contexts (default expressions, within a task body) + -- are not subject to this restriction. + + if not In_Default_Expression + and then not Has_Completion (Scop) + and then + Nkind (Parent (N)) /= N_Discriminant_Association + and then + Nkind (Parent (N)) /= N_Index_Or_Discriminant_Constraint + then + Error_Msg_N + ("current instance attribute must appear alone", N); + end if; + + -- OK if we are in initialization procedure for the type + -- in question, in which case the reference to the type + -- is rewritten as a reference to the current object. + + elsif Ekind (Scop) = E_Procedure + and then 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; + + -- 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; + + -- 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. + + if Is_Entity_Name (P) then + Set_Never_Set_In_Source (Entity (P), False); + end if; + + -- Check for aliased view unless unrestricted case. We allow + -- a nonaliased prefix when within an instance because the + -- prefix may have been a tagged formal object, which is + -- defined to be aliased even when the actual might not be + -- (other instance cases will have been caught in the generic). + -- 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 ("prefix of % attribute must be aliased", P); + end if; + end Analyze_Access_Attribute; + + -------------------------------- + -- Check_Array_Or_Scalar_Type -- + -------------------------------- + + procedure Check_Array_Or_Scalar_Type is + Index : Entity_Id; + + D : Int; + -- Dimension number for array attributes + + begin + -- Case of string literal or string literal subtype. These cases + -- cannot arise from legal Ada code, but the expander is allowed + -- to generate them. They require special handling because string + -- literal subtypes do not have standard bounds (the whole idea + -- of these subtypes is to avoid having to generate the bounds) + + if Ekind (P_Type) = E_String_Literal_Subtype then + Set_Etype (N, Etype (First_Index (P_Base_Type))); + return; + + -- Scalar types + + elsif Is_Scalar_Type (P_Type) then + Check_Type; + + if Present (E1) then + Error_Attr ("invalid argument in % attribute", E1); + else + Set_Etype (N, P_Base_Type); + return; + end if; + + -- The following is a special test to allow 'First to apply to + -- private scalar types if the attribute comes from generated + -- code. This occurs in the case of Normalize_Scalars code. + + elsif Is_Private_Type (P_Type) + and then Present (Full_View (P_Type)) + and then Is_Scalar_Type (Full_View (P_Type)) + and then not Comes_From_Source (N) + then + Set_Etype (N, Implementation_Base_Type (P_Type)); + + -- Array types other than string literal subtypes handled above + + else + Check_Array_Type; + + -- We know prefix is an array type, or the name of an array + -- object, and that the expression, if present, is static + -- and within the range of the dimensions of the type. + + 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_N + ("prefix for % attribute must be constrained array", P); + end if; + + D := Number_Dimensions (P_Type); + + else + if Is_Private_Type (P_Type) then + Error_Attr + ("prefix for % attribute may not be private type", P); + + 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 ("prefix of % attribute cannot be access type", P); + + elsif Attr_Id = Attribute_First + or else + Attr_Id = Attribute_Last + then + Error_Attr ("invalid prefix for % attribute", P); + + else + Error_Attr ("prefix for % attribute must be array", P); + end if; + end if; + + if Present (E1) then + Resolve (E1, Any_Integer); + Set_Etype (E1, Standard_Integer); + + if not Is_Static_Expression (E1) + or else Raises_Constraint_Error (E1) + then + 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; + 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 + ("prefix for % attribute must be selected component", P); + end if; + end Check_Component; + + ------------------------------------ + -- Check_Decimal_Fixed_Point_Type -- + ------------------------------------ + + procedure Check_Decimal_Fixed_Point_Type is + begin + Check_Type; + + if not Is_Decimal_Fixed_Point_Type (P_Type) then + Error_Attr + ("prefix of % attribute must be decimal type", P); + end if; + end Check_Decimal_Fixed_Point_Type; + + ----------------------- + -- Check_Dereference -- + ----------------------- + + procedure Check_Dereference is + begin + + -- 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). + + Freeze_Before (N, Designated_Type (P_Type)); + + 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 ("prefix of % attribute must be discrete type", P); + end if; + end Check_Discrete_Type; + + -------------- + -- Check_E0 -- + -------------- + + procedure Check_E0 is + begin + if Present (E1) then + Unexpected_Argument (E1); + end if; + end Check_E0; + + -------------- + -- Check_E1 -- + -------------- + + procedure Check_E1 is + begin + Check_Either_E0_Or_E1; + + if No (E1) then + + -- Special-case attributes that are functions and that appear as + -- the prefix of another attribute. Error is posted on parent. + + if Nkind (Parent (N)) = N_Attribute_Reference + and then (Attribute_Name (Parent (N)) = Name_Address + or else + Attribute_Name (Parent (N)) = Name_Code_Address + or else + Attribute_Name (Parent (N)) = Name_Access) + then + Error_Msg_Name_1 := Attribute_Name (Parent (N)); + Error_Msg_N ("illegal prefix for % attribute", Parent (N)); + Set_Etype (Parent (N), Any_Type); + Set_Entity (Parent (N), Any_Type); + raise Bad_Attribute; + + else + Error_Attr ("missing argument for % attribute", N); + end if; + end if; + end Check_E1; + + -------------- + -- Check_E2 -- + -------------- + + procedure Check_E2 is + begin + if No (E1) then + Error_Attr ("missing arguments for % attribute (2 required)", N); + elsif No (E2) then + Error_Attr ("missing argument for % attribute (2 required)", N); + end if; + end Check_E2; + + --------------------------- + -- Check_Either_E0_Or_E1 -- + --------------------------- + + procedure Check_Either_E0_Or_E1 is + begin + if Present (E2) then + Unexpected_Argument (E2); + end if; + end Check_Either_E0_Or_E1; + + ---------------------- + -- Check_Enum_Image -- + ---------------------- + + procedure Check_Enum_Image is + Lit : Entity_Id; + + begin + if Is_Enumeration_Type (P_Base_Type) then + Lit := First_Literal (P_Base_Type); + while Present (Lit) loop + Set_Referenced (Lit); + Next_Literal (Lit); + end loop; + end if; + end Check_Enum_Image; + + ---------------------------- + -- Check_Fixed_Point_Type -- + ---------------------------- + + procedure Check_Fixed_Point_Type is + begin + Check_Type; + + if not Is_Fixed_Point_Type (P_Type) then + Error_Attr ("prefix of % attribute must be fixed point type", P); + end if; + end Check_Fixed_Point_Type; + + ------------------------------ + -- Check_Fixed_Point_Type_0 -- + ------------------------------ + + procedure Check_Fixed_Point_Type_0 is + begin + Check_Fixed_Point_Type; + Check_E0; + end Check_Fixed_Point_Type_0; + + ------------------------------- + -- Check_Floating_Point_Type -- + ------------------------------- + + procedure Check_Floating_Point_Type is + begin + Check_Type; + + if not Is_Floating_Point_Type (P_Type) then + Error_Attr ("prefix of % attribute must be float type", P); + end if; + end Check_Floating_Point_Type; + + --------------------------------- + -- Check_Floating_Point_Type_0 -- + --------------------------------- + + procedure Check_Floating_Point_Type_0 is + begin + Check_Floating_Point_Type; + Check_E0; + end Check_Floating_Point_Type_0; + + --------------------------------- + -- Check_Floating_Point_Type_1 -- + --------------------------------- + + procedure Check_Floating_Point_Type_1 is + begin + Check_Floating_Point_Type; + Check_E1; + end Check_Floating_Point_Type_1; + + --------------------------------- + -- Check_Floating_Point_Type_2 -- + --------------------------------- + + procedure Check_Floating_Point_Type_2 is + begin + Check_Floating_Point_Type; + Check_E2; + end Check_Floating_Point_Type_2; + + ------------------------ + -- Check_Integer_Type -- + ------------------------ + + procedure Check_Integer_Type is + begin + Check_Type; + + if not Is_Integer_Type (P_Type) then + Error_Attr ("prefix of % attribute must be integer type", P); + end if; + end Check_Integer_Type; + + ------------------------ + -- Check_Library_Unit -- + ------------------------ + + procedure Check_Library_Unit is + begin + if not Is_Compilation_Unit (Entity (P)) then + Error_Attr ("prefix of % attribute must be library unit", P); + end if; + end Check_Library_Unit; + + -------------------------------- + -- Check_Modular_Integer_Type -- + -------------------------------- + + procedure Check_Modular_Integer_Type is + begin + Check_Type; + + if not Is_Modular_Integer_Type (P_Type) then + Error_Attr + ("prefix of % attribute must be modular integer type", P); + end if; + end Check_Modular_Integer_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_05 + and then Nkind (P) = N_Explicit_Dereference + then + E := P; + while Nkind (E) = N_Explicit_Dereference loop + E := Prefix (E); + end loop; + + if From_With_Type (Etype (E)) then + Error_Attr + ("prefix of % attribute cannot be an incomplete type", P); + + else + if Is_Access_Type (Etype (E)) then + Typ := Directly_Designated_Type (Etype (E)); + else + Typ := Etype (E); + end if; + + if Ekind (Typ) = E_Incomplete_Type + and then No (Full_View (Typ)) + then + Error_Attr + ("prefix of % attribute cannot be an incomplete type", P); + end if; + end if; + end if; + + if not Is_Entity_Name (P) + or else not Is_Type (Entity (P)) + or else In_Default_Expression + then + return; + else + Check_Fully_Declared (P_Type, P); + end if; + end Check_Not_Incomplete_Type; + + ---------------------------- + -- Check_Object_Reference -- + ---------------------------- + + procedure Check_Object_Reference (P : Node_Id) is + Rtyp : Entity_Id; + + begin + -- If we need an object, and we have a prefix that is the name of + -- a function entity, convert it into a function call. + + if Is_Entity_Name (P) + and then Ekind (Entity (P)) = E_Function + then + Rtyp := Etype (Entity (P)); + + Rewrite (P, + Make_Function_Call (Sloc (P), + Name => Relocate_Node (P))); + + Analyze_And_Resolve (P, Rtyp); + + -- Otherwise we must have an object reference + + elsif not Is_Object_Reference (P) then + Error_Attr ("prefix of % attribute must be object", P); + end if; + end Check_Object_Reference; + + ------------------------ + -- Check_Program_Unit -- + ------------------------ + + procedure Check_Program_Unit is + begin + if Is_Entity_Name (P) then + declare + K : constant Entity_Kind := Ekind (Entity (P)); + T : constant Entity_Id := Etype (Entity (P)); + + begin + if K in Subprogram_Kind + or else K in Task_Kind + or else K in Protected_Kind + or else K = E_Package + or else K in Generic_Unit_Kind + or else (K = E_Variable + and then + (Is_Task_Type (T) + or else + Is_Protected_Type (T))) + then + return; + end if; + end; + end if; + + Error_Attr ("prefix of % attribute must be program unit", P); + end Check_Program_Unit; + + --------------------- + -- Check_Real_Type -- + --------------------- + + procedure Check_Real_Type is + begin + Check_Type; + + if not Is_Real_Type (P_Type) then + Error_Attr ("prefix of % attribute must be real type", P); + end if; + end Check_Real_Type; + + ----------------------- + -- Check_Scalar_Type -- + ----------------------- + + procedure Check_Scalar_Type is + begin + Check_Type; + + if not Is_Scalar_Type (P_Type) then + Error_Attr ("prefix of % attribute must be scalar type", P); + end if; + end Check_Scalar_Type; + + --------------------------- + -- Check_Standard_Prefix -- + --------------------------- + + procedure Check_Standard_Prefix is + begin + Check_E0; + + if Nkind (P) /= N_Identifier + or else Chars (P) /= Name_Standard + then + Error_Attr ("only allowed prefix for % attribute is Standard", P); + end if; + + end Check_Standard_Prefix; + + ---------------------------- + -- Check_Stream_Attribute -- + ---------------------------- + + procedure Check_Stream_Attribute (Nam : TSS_Name_Type) is + Etyp : Entity_Id; + Btyp : Entity_Id; + begin + Validate_Non_Static_Attribute_Function_Call; + + -- With the exception of 'Input, Stream attributes are procedures, + -- and can only appear at the position of procedure calls. We check + -- for this here, before they are rewritten, to give a more precise + -- diagnostic. + + if Nam = TSS_Stream_Input then + null; + + elsif Is_List_Member (N) + and then Nkind (Parent (N)) /= N_Procedure_Call_Statement + and then Nkind (Parent (N)) /= N_Aggregate + then + null; + + else + Error_Attr + ("invalid context for attribute%, which is a procedure", N); + end if; + + Check_Type; + Btyp := Implementation_Base_Type (P_Type); + + -- Stream attributes not allowed on limited types unless the + -- 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). + + if Comes_From_Source (N) + and then not Stream_Attribute_Available (P_Type, Nam) + and then not Has_Rep_Pragma (Btyp, Name_Stream_Convert) + then + Error_Msg_Name_1 := Aname; + + if Is_Limited_Type (P_Type) then + Error_Msg_NE + ("limited type& has no% attribute", P, P_Type); + Explain_Limited_Type (P_Type, P); + else + Error_Msg_NE + ("attribute% for type& is not available", P, P_Type); + end if; + end if; + + -- Check for violation of restriction No_Stream_Attributes + + if 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; + 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_05 + 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_05 then + Error_Attr ("prefix of % attribute must be a task or a task " + & "interface class-wide object", P); + + else + Error_Attr ("prefix of % attribute must be a task", P); + 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 ("prefix of % attribute must be a type", P); + + elsif Ekind (Entity (P)) = E_Incomplete_Type + and then Present (Full_View (Entity (P))) + then + P_Type := Full_View (Entity (P)); + Set_Entity (P, P_Type); + end if; + end Check_Type; + + --------------------- + -- Check_Unit_Name -- + --------------------- + + procedure Check_Unit_Name (Nod : Node_Id) is + begin + if Nkind (Nod) = N_Identifier then + return; + + elsif Nkind (Nod) = N_Selected_Component then + Check_Unit_Name (Prefix (Nod)); + + if Nkind (Selector_Name (Nod)) = N_Identifier then + return; + end if; + end if; + + Error_Attr ("argument for % attribute must be unit name", P); + end Check_Unit_Name; + + ---------------- + -- Error_Attr -- + ---------------- + + procedure Error_Attr 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; + + ---------------------------- + -- Legal_Formal_Attribute -- + ---------------------------- + + procedure Legal_Formal_Attribute is + begin + Check_E0; + + if not Is_Entity_Name (P) + or else not Is_Type (Entity (P)) + then + Error_Attr ("prefix of % attribute must be generic type", N); + + elsif Is_Generic_Actual_Type (Entity (P)) + or 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 + ("prefix of % attribute must be indefinite generic type", N); + end if; + + else + Error_Attr + ("prefix of % attribute must be indefinite generic type", N); + end if; + + Set_Etype (N, Standard_Boolean); + end Legal_Formal_Attribute; + + ------------------------ + -- Standard_Attribute -- + ------------------------ + + procedure Standard_Attribute (Val : Int) is + begin + Check_Standard_Prefix; + + -- First a special check (more like a kludge really). For GNAT5 + -- on Windows, the alignments in GCC are severely mixed up. In + -- particular, we have a situation where the maximum alignment + -- that GCC thinks is possible is greater than the guaranteed + -- alignment at run-time. That causes many problems. As a partial + -- cure for this situation, we force a value of 4 for the maximum + -- alignment attribute on this target. This still does not solve + -- all problems, but it helps. + + -- A further (even more horrible) dimension to this kludge is now + -- installed. There are two uses for Maximum_Alignment, one is to + -- determine the maximum guaranteed alignment, that's the one we + -- want the kludge to yield as 4. The other use is to maximally + -- align objects, we can't use 4 here, since for example, long + -- long integer has an alignment of 8, so we will get errors. + + -- It is of course impossible to determine which use the programmer + -- has in mind, but an approximation for now is to disconnect the + -- kludge if the attribute appears in an alignment clause. + + -- To be removed if GCC ever gets its act together here ??? + + Alignment_Kludge : declare + P : Node_Id; + + function On_X86 return Boolean; + -- Determine if target is x86 (ia32), return True if so + + ------------ + -- On_X86 -- + ------------ + + function On_X86 return Boolean is + T : constant String := Sdefault.Target_Name.all; + + begin + -- There is no clean way to check this. That's not surprising, + -- the front end should not be doing this kind of test ???. The + -- way we do it is test for either "86" or "pentium" being in + -- the string for the target name. However, we need to exclude + -- x86_64 for this check. + + for J in T'First .. T'Last - 1 loop + if (T (J .. J + 1) = "86" + and then + (J + 4 > T'Last + or else T (J + 2 .. J + 4) /= "_64")) + or else (J <= T'Last - 6 + and then T (J .. J + 6) = "pentium") + then + return True; + end if; + end loop; + + return False; + end On_X86; + + begin + if Aname = Name_Maximum_Alignment and then On_X86 then + P := Parent (N); + + while Nkind (P) in N_Subexpr loop + P := Parent (P); + end loop; + + if Nkind (P) /= N_Attribute_Definition_Clause + or else Chars (P) /= Name_Alignment + then + Rewrite (N, Make_Integer_Literal (Loc, 4)); + Analyze (N); + return; + end if; + end if; + end Alignment_Kludge; + + -- Normally we get the value from gcc ??? + + 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 and Features 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; + + -- 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. A special case is + -- that we never analyze the prefix of an Elab_Body or Elab_Spec + -- or UET_Address attribute. + + if Aname /= Name_Elab_Body + and then + Aname /= Name_Elab_Spec + and then + Aname /= Name_UET_Address + then + Analyze (P); + P_Type := Etype (P); + + if Is_Entity_Name (P) + and then Present (Entity (P)) + and then Is_Type (Entity (P)) + then + if Ekind (Entity (P)) = E_Incomplete_Type then + P_Type := Get_Full_View (P_Type); + Set_Entity (P, P_Type); + Set_Etype (P, P_Type); + + elsif Entity (P) = Current_Scope + and then Is_Record_Type (Entity (P)) + then + + -- Use of current instance within the type. Verify that if the + -- attribute appears within a constraint, it yields an access + -- type, other uses are illegal. + + declare + Par : Node_Id; + + begin + Par := Parent (N); + while Present (Par) + and then Nkind (Parent (Par)) /= N_Component_Definition + loop + Par := Parent (Par); + end loop; + + if Present (Par) + and then Nkind (Par) = N_Subtype_Indication + then + if Attr_Id /= Attribute_Access + and then Attr_Id /= Attribute_Unchecked_Access + and then Attr_Id /= Attribute_Unrestricted_Access + then + Error_Msg_N + ("in a constraint the current instance can only" + & " be used with an access attribute", N); + end if; + end if; + end; + end if; + end if; + + if P_Type = Any_Type then + raise Bad_Attribute; + end if; + + P_Base_Type := Base_Type (P_Type); + end if; + + -- Analyze expressions that may be present, exiting if an error occurs + + if No (Exprs) then + E1 := Empty; + E2 := Empty; + + else + E1 := First (Exprs); + Analyze (E1); + + -- Check for missing or bad expression (result of previous error) + + if No (E1) or else Etype (E1) = Any_Type then + raise Bad_Attribute; + end if; + + E2 := Next (E1); + + if Present (E2) then + Analyze (E2); + + if Etype (E2) = Any_Type then + raise Bad_Attribute; + end if; + + if Present (Next (E2)) then + Unexpected_Argument (Next (E2)); + end if; + end if; + end if; + + -- Ada 2005 (AI-345): Ensure that the compiler gives exactly the current + -- output compiling in Ada 95 mode + + if Ada_Version < Ada_05 + 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_Unchecked_Access + then + Error_Attr ("ambiguous prefix for % attribute", P); + + elsif Ada_Version >= Ada_05 + 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_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_05 + 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; + + -- Remaining processing depends on attribute + + case Attr_Id is + + ------------------ + -- Abort_Signal -- + ------------------ + + when Attribute_Abort_Signal => + Check_Standard_Prefix; + Rewrite (N, + New_Reference_To (Stand.Abort_Signal, Loc)); + Analyze (N); + + ------------ + -- Access -- + ------------ + + when Attribute_Access => + 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_Entity_Name (P) then + declare + Ent : constant Entity_Id := Entity (P); + + begin + if Is_Subprogram (Ent) then + if not Is_Library_Level_Entity (Ent) then + Check_Restriction (No_Implicit_Dynamic_Code, P); + end if; + + Set_Address_Taken (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 Is_Always_Inlined (Entity (P)) + and then Comes_From_Source (P) + then + Error_Attr + ("prefix of % attribute cannot be Inline_Always" & + " subprogram", P); + end if; + + elsif Is_Object (Ent) + or else Ekind (Ent) = E_Label + then + Set_Address_Taken (Ent); + + -- 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; + Set_Etype (N, Universal_Integer); + + --------------- + -- Asm_Input -- + --------------- + + when Attribute_Asm_Input => + Check_Asm_Attribute; + Set_Etype (N, RTE (RE_Asm_Input_Operand)); + + ---------------- + -- Asm_Output -- + ---------------- + + when Attribute_Asm_Output => + Check_Asm_Attribute; + + if Etype (E2) = Any_Type then + return; + + elsif Aname = Name_Asm_Output then + if not Is_Variable (E2) then + Error_Attr + ("second argument for Asm_Output is not variable", E2); + end if; + end if; + + Note_Possible_Modification (E2); + Set_Etype (N, RTE (RE_Asm_Output_Operand)); + + --------------- + -- AST_Entry -- + --------------- + + when Attribute_AST_Entry => AST_Entry : declare + Ent : Entity_Id; + Pref : Node_Id; + Ptyp : Entity_Id; + + Indexed : Boolean; + -- Indicates if entry family index is present. Note the coding + -- here handles the entry family case, but in fact it cannot be + -- executed currently, because pragma AST_Entry does not permit + -- the specification of an entry family. + + procedure Bad_AST_Entry; + -- Signal a bad AST_Entry pragma + + function OK_Entry (E : Entity_Id) return Boolean; + -- Checks that E is of an appropriate entity kind for an entry + -- (i.e. E_Entry if Index is False, or E_Entry_Family if Index + -- is set True for the entry family case). In the True case, + -- makes sure that Is_AST_Entry is set on the entry. + + procedure Bad_AST_Entry is + begin + Error_Attr ("prefix for % attribute must be task entry", P); + end Bad_AST_Entry; + + function OK_Entry (E : Entity_Id) return Boolean is + Result : Boolean; + + begin + if Indexed then + Result := (Ekind (E) = E_Entry_Family); + else + Result := (Ekind (E) = E_Entry); + end if; + + if Result then + if not Is_AST_Entry (E) then + Error_Msg_Name_2 := Aname; + Error_Attr + ("% attribute requires previous % pragma", P); + end if; + end if; + + return Result; + end OK_Entry; + + -- Start of processing for AST_Entry + + begin + Check_VMS (N); + Check_E0; + + -- Deal with entry family case + + if Nkind (P) = N_Indexed_Component then + Pref := Prefix (P); + Indexed := True; + else + Pref := P; + Indexed := False; + end if; + + Ptyp := Etype (Pref); + + if Ptyp = Any_Type or else Error_Posted (Pref) then + return; + end if; + + -- If the prefix is a selected component whose prefix is of an + -- access type, then introduce an explicit dereference. + -- ??? 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 (Pref) = N_Identifier + or else Nkind (Pref) = N_Expanded_Name + then + Ent := Entity (Pref); + + if not OK_Entry (Ent) + or else not In_Open_Scopes (Scope (Ent)) + then + Bad_AST_Entry; + end if; + + else + Bad_AST_Entry; + end if; + end if; + + Set_Etype (N, RTE (RE_AST_Handler)); + end AST_Entry; + + ---------- + -- Base -- + ---------- + + -- 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_Either_E0_Or_E1; + 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_Msg_N ("prefix of Base attribute must be scalar type", N); + + elsif Sloc (Typ) = Standard_Location + and then Base_Type (Typ) = Typ + and then Warn_On_Redundant_Constructs + then + Error_Msg_NE + ("?redudant attribute, & is its own base type", N, Typ); + end if; + + Set_Etype (N, Base_Type (Entity (P))); + + -- If we have an expression present, then really this is a conversion + -- and the tree must be reformed. Note that this is one of the cases + -- in which we do a replace rather than a rewrite, because the + -- original tree is junk. + + if Present (E1) then + Replace (N, + Make_Type_Conversion (Loc, + Subtype_Mark => + Make_Attribute_Reference (Loc, + Prefix => Prefix (N), + Attribute_Name => Name_Base), + Expression => Relocate_Node (E1))); + + -- E1 may be overloaded, and its interpretations preserved + + Save_Interps (E1, Expression (N)); + Analyze (N); + + -- For other cases, set the proper type as the entity of the + -- attribute reference, and then rewrite the node to be an + -- occurrence of the referenced base type. This way, no one + -- else in the compiler has to worry about the base attribute. + + else + Set_Entity (N, Base_Type (Entity (P))); + Rewrite (N, + New_Reference_To (Entity (N), Loc)); + Analyze (N); + end if; + end Base; + + --------- + -- Bit -- + --------- + + when Attribute_Bit => Bit : + begin + Check_E0; + + if not Is_Object_Reference (P) then + Error_Attr ("prefix for % attribute must be object", P); + + -- What about the access object cases ??? + + else + null; + end if; + + Set_Etype (N, Universal_Integer); + end Bit; + + --------------- + -- Bit_Order -- + --------------- + + when Attribute_Bit_Order => Bit_Order : + begin + Check_E0; + Check_Type; + + if not Is_Record_Type (P_Type) then + Error_Attr ("prefix of % attribute must be record type", P); + end if; + + if Bytes_Big_Endian xor Reverse_Bit_Order (P_Type) then + Rewrite (N, + New_Occurrence_Of (RTE (RE_High_Order_First), Loc)); + else + Rewrite (N, + New_Occurrence_Of (RTE (RE_Low_Order_First), Loc)); + end if; + + Set_Etype (N, RTE (RE_Bit_Order)); + Resolve (N); + + -- Reset incorrect indication of staticness + + Set_Is_Static_Expression (N, False); + end Bit_Order; + + ------------------ + -- Bit_Position -- + ------------------ + + -- Note: in generated code, we can have a Bit_Position attribute + -- applied to a (naked) record component (i.e. the prefix is an + -- identifier that references an E_Component or E_Discriminant + -- entity directly, and this is interpreted as expected by Gigi. + -- The following code will not tolerate such usage, but when the + -- expander creates this special case, it marks it as analyzed + -- immediately and sets an appropriate type. + + when Attribute_Bit_Position => + + if Comes_From_Source (N) then + Check_Component; + end if; + + Set_Etype (N, Universal_Integer); + + ------------------ + -- Body_Version -- + ------------------ + + when Attribute_Body_Version => + Check_E0; + Check_Program_Unit; + Set_Etype (N, RTE (RE_Version_String)); + + -------------- + -- Callable -- + -------------- + + when Attribute_Callable => + Check_E0; + Set_Etype (N, Standard_Boolean); + Check_Task_Prefix; + + ------------ + -- Caller -- + ------------ + + when Attribute_Caller => Caller : declare + Ent : Entity_Id; + S : Entity_Id; + + begin + Check_E0; + + if Nkind (P) = N_Identifier + or else Nkind (P) = N_Expanded_Name + then + Ent := Entity (P); + + if not Is_Entry (Ent) then + Error_Attr ("invalid entry name", N); + end if; + + else + Error_Attr ("invalid entry name", N); + return; + end if; + + for J in reverse 0 .. Scope_Stack.Last loop + S := Scope_Stack.Table (J).Entity; + + if S = Scope (Ent) then + Error_Attr ("Caller must appear in matching accept or body", N); + elsif S = Ent then + exit; + end if; + end loop; + + Set_Etype (N, RTE (RO_AT_Task_Id)); + end Caller; + + ------------- + -- Ceiling -- + ------------- + + when Attribute_Ceiling => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ----------- + -- Class -- + ----------- + + when Attribute_Class => Class : declare + P : constant Entity_Id := Prefix (N); + + begin + Check_Restriction (No_Dispatch, N); + Check_Either_E0_Or_E1; + + -- If we have an expression present, then really this is a conversion + -- and the tree must be reformed into a proper conversion. This is a + -- Replace rather than a Rewrite, because the original tree is junk. + -- If expression is overloaded, propagate interpretations to new one. + + if Present (E1) then + Replace (N, + Make_Type_Conversion (Loc, + Subtype_Mark => + Make_Attribute_Reference (Loc, + Prefix => P, + Attribute_Name => Name_Class), + Expression => Relocate_Node (E1))); + + Save_Interps (E1, Expression (N)); + + if not Is_Interface (Etype (P)) then + Analyze (N); + + -- Ada 2005 (AI-251): In case of abstract interfaces we have to + -- analyze and resolve the type conversion to generate the code + -- that displaces the reference to the base of the object. + + else + Analyze_And_Resolve (N, Etype (P)); + end if; + + -- Otherwise we just need to find the proper type + + else + Find_Type (N); + end if; + + end Class; + + ------------------ + -- Code_Address -- + ------------------ + + when Attribute_Code_Address => + Check_E0; + + if Nkind (P) = N_Attribute_Reference + and then (Attribute_Name (P) = Name_Elab_Body + or else + Attribute_Name (P) = Name_Elab_Spec) + then + null; + + elsif not Is_Entity_Name (P) + or else (Ekind (Entity (P)) /= E_Function + and then + Ekind (Entity (P)) /= E_Procedure) + then + Error_Attr ("invalid prefix for % attribute", P); + Set_Address_Taken (Entity (P)); + end if; + + Set_Etype (N, RTE (RE_Address)); + + -------------------- + -- Component_Size -- + -------------------- + + when Attribute_Component_Size => + Check_E0; + Set_Etype (N, Universal_Integer); + + -- Note: unlike other array attributes, unconstrained arrays are OK + + if Is_Array_Type (P_Type) and then not Is_Constrained (P_Type) then + null; + else + Check_Array_Type; + end if; + + ------------- + -- Compose -- + ------------- + + when Attribute_Compose => + Check_Floating_Point_Type_2; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + Resolve (E2, Any_Integer); + + ----------------- + -- Constrained -- + ----------------- + + when Attribute_Constrained => + Check_E0; + Set_Etype (N, Standard_Boolean); + + -- Case from RM J.4(2) of constrained applied to private type + + if Is_Entity_Name (P) and then Is_Type (Entity (P)) then + Check_Restriction (No_Obsolescent_Features, N); + + if Warn_On_Obsolescent_Feature then + Error_Msg_N + ("constrained for private type is an " & + "obsolescent feature ('R'M 'J.4)?", 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 + ("prefix of % attribute must be object of discriminated type", P); + + --------------- + -- Copy_Sign -- + --------------- + + when Attribute_Copy_Sign => + Check_Floating_Point_Type_2; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + Resolve (E2, P_Base_Type); + + ----------- + -- Count -- + ----------- + + when Attribute_Count => Count : + declare + Ent : Entity_Id; + S : Entity_Id; + Tsk : Entity_Id; + + begin + Check_E0; + + if Nkind (P) = N_Identifier + or else Nkind (P) = N_Expanded_Name + then + Ent := Entity (P); + + if Ekind (Ent) /= E_Entry then + Error_Attr ("invalid entry name", N); + end if; + + elsif Nkind (P) = N_Indexed_Component then + 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 Ekind (S) /= E_Loop + and then Ekind (S) /= E_Block + and then Ekind (S) /= E_Entry + and then Ekind (S) /= E_Entry_Family + then + Error_Attr ("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_05 + 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; + Check_E0; + + if Bytes_Big_Endian then + Rewrite (N, + Make_Integer_Literal (Loc, False_Value)); + else + Rewrite (N, + Make_Integer_Literal (Loc, True_Value)); + end if; + + Set_Etype (N, Universal_Integer); + Set_Is_Static_Expression (N); + end Default_Bit_Order; + + -------------- + -- Definite -- + -------------- + + when Attribute_Definite => + Legal_Formal_Attribute; + + ----------- + -- Delta -- + ----------- + + when Attribute_Delta => + Check_Fixed_Point_Type_0; + Set_Etype (N, Universal_Real); + + ------------ + -- Denorm -- + ------------ + + when Attribute_Denorm => + Check_Floating_Point_Type_0; + Set_Etype (N, Standard_Boolean); + + ------------ + -- Digits -- + ------------ + + when Attribute_Digits => + Check_E0; + Check_Type; + + if not Is_Floating_Point_Type (P_Type) + and then not Is_Decimal_Fixed_Point_Type (P_Type) + then + Error_Attr + ("prefix of % attribute must be float or decimal type", P); + end if; + + Set_Etype (N, Universal_Integer); + + --------------- + -- Elab_Body -- + --------------- + + -- Also handles processing for Elab_Spec + + when Attribute_Elab_Body | Attribute_Elab_Spec => + Check_E0; + Check_Unit_Name (P); + Set_Etype (N, Standard_Void_Type); + + -- We have to manually call the expander in this case to get + -- the necessary expansion (normally attributes that return + -- entities are not expanded). + + Expand (N); + + --------------- + -- Elab_Spec -- + --------------- + + -- Shares processing with Elab_Body + + ---------------- + -- Elaborated -- + ---------------- + + when Attribute_Elaborated => + Check_E0; + Check_Library_Unit; + Set_Etype (N, Standard_Boolean); + + ---------- + -- Emax -- + ---------- + + when Attribute_Emax => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Integer); + + -------------- + -- Enum_Rep -- + -------------- + + when Attribute_Enum_Rep => Enum_Rep : declare + begin + if Present (E1) then + Check_E1; + Check_Discrete_Type; + Resolve (E1, P_Base_Type); + + else + if not Is_Entity_Name (P) + or else (not Is_Object (Entity (P)) + and then + Ekind (Entity (P)) /= E_Enumeration_Literal) + then + Error_Attr + ("prefix of %attribute must be " & + "discrete type/object or enum literal", P); + end if; + end if; + + Set_Etype (N, Universal_Integer); + end Enum_Rep; + + ------------- + -- Epsilon -- + ------------- + + when Attribute_Epsilon => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Real); + + -------------- + -- Exponent -- + -------------- + + when Attribute_Exponent => + Check_Floating_Point_Type_1; + Set_Etype (N, Universal_Integer); + Resolve (E1, P_Base_Type); + + ------------------ + -- External_Tag -- + ------------------ + + when Attribute_External_Tag => + Check_E0; + Check_Type; + + Set_Etype (N, Standard_String); + + if not Is_Tagged_Type (P_Type) then + Error_Attr ("prefix of % attribute must be tagged", P); + end if; + + ----------- + -- First -- + ----------- + + when Attribute_First => + Check_Array_Or_Scalar_Type; + + --------------- + -- First_Bit -- + --------------- + + when Attribute_First_Bit => + Check_Component; + Set_Etype (N, Universal_Integer); + + ----------------- + -- Fixed_Value -- + ----------------- + + when Attribute_Fixed_Value => + Check_E1; + Check_Fixed_Point_Type; + Resolve (E1, Any_Integer); + Set_Etype (N, P_Base_Type); + + ----------- + -- Floor -- + ----------- + + when Attribute_Floor => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ---------- + -- Fore -- + ---------- + + when Attribute_Fore => + Check_Fixed_Point_Type_0; + Set_Etype (N, Universal_Integer); + + -------------- + -- Fraction -- + -------------- + + when Attribute_Fraction => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ----------------------- + -- Has_Access_Values -- + ----------------------- + + when Attribute_Has_Access_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_05 + 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_05 then + Error_Attr ("prefix of % attribute must be an exception, a " + & "task or a task interface class-wide object", P); + else + Error_Attr ("prefix of % attribute must be a task or an " + & "exception", P); + end if; + end if; + + ----------- + -- Image -- + ----------- + + when Attribute_Image => Image : + begin + Set_Etype (N, Standard_String); + Check_Scalar_Type; + + if Is_Real_Type (P_Type) then + if Ada_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 + Set_Etype (N, Standard_String); + + if not Is_Scalar_Type (P_Type) + or else (Is_Entity_Name (P) and then Is_Type (Entity (P))) + then + Error_Attr + ("prefix of % attribute must be scalar object name", N); + end if; + + Check_Enum_Image; + end Img; + + ----------- + -- Input -- + ----------- + + when Attribute_Input => + Check_E1; + Check_Stream_Attribute (TSS_Stream_Input); + Set_Etype (N, P_Base_Type); + + ------------------- + -- Integer_Value -- + ------------------- + + when Attribute_Integer_Value => + Check_E1; + Check_Integer_Type; + Resolve (E1, Any_Fixed); + Set_Etype (N, P_Base_Type); + + ----------- + -- Large -- + ----------- + + when Attribute_Large => + Check_E0; + Check_Real_Type; + Set_Etype (N, Universal_Real); + + ---------- + -- Last -- + ---------- + + when Attribute_Last => + Check_Array_Or_Scalar_Type; + + -------------- + -- Last_Bit -- + -------------- + + when Attribute_Last_Bit => + Check_Component; + Set_Etype (N, Universal_Integer); + + ------------------ + -- Leading_Part -- + ------------------ + + when Attribute_Leading_Part => + Check_Floating_Point_Type_2; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + Resolve (E2, Any_Integer); + + ------------ + -- Length -- + ------------ + + when Attribute_Length => + Check_Array_Type; + Set_Etype (N, Universal_Integer); + + ------------- + -- Machine -- + ------------- + + when Attribute_Machine => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ------------------ + -- Machine_Emax -- + ------------------ + + when Attribute_Machine_Emax => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Integer); + + ------------------ + -- Machine_Emin -- + ------------------ + + when Attribute_Machine_Emin => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Integer); + + ---------------------- + -- Machine_Mantissa -- + ---------------------- + + when Attribute_Machine_Mantissa => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Integer); + + ----------------------- + -- Machine_Overflows -- + ----------------------- + + when Attribute_Machine_Overflows => + Check_Real_Type; + Check_E0; + Set_Etype (N, Standard_Boolean); + + ------------------- + -- Machine_Radix -- + ------------------- + + when Attribute_Machine_Radix => + Check_Real_Type; + Check_E0; + Set_Etype (N, Universal_Integer); + + ---------------------- + -- Machine_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_Size_In_Storage_Elements -- + ---------------------------------- + + when Attribute_Max_Size_In_Storage_Elements => + Check_E0; + Check_Type; + Check_Not_Incomplete_Type; + Set_Etype (N, Universal_Integer); + + ----------------------- + -- Maximum_Alignment -- + ----------------------- + + when Attribute_Maximum_Alignment => + Standard_Attribute (Ttypes.Maximum_Alignment); + + -------------------- + -- Mechanism_Code -- + -------------------- + + when Attribute_Mechanism_Code => + if not Is_Entity_Name (P) + or else not Is_Subprogram (Entity (P)) + then + Error_Attr ("prefix of % attribute must be subprogram", P); + end if; + + Check_Either_E0_Or_E1; + + if Present (E1) then + Resolve (E1, Any_Integer); + Set_Etype (E1, Standard_Integer); + + if not Is_Static_Expression (E1) then + 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 : Entity_Id := Proc_Ent; + + begin + while Present (Alias (Pent)) loop + Pent := Alias (Pent); + end loop; + + -- Ignore check if procedure not frozen yet (we will get + -- another chance when the default parameter is reanalyzed) + + if not Is_Frozen (Pent) then + return; + + elsif not Is_Imported (Pent) then + Bad_Null_Parameter + ("Null_Parameter can only be used with imported subprogram"); + + else + return; + end if; + end Must_Be_Imported; + + -- Start of processing for Null_Parameter + + begin + Check_Type; + Check_E0; + Set_Etype (N, P_Type); + + -- Case of attribute used as default expression + + if Nkind (Parnt) = N_Parameter_Specification then + Must_Be_Imported (Defining_Entity (GParnt)); + + -- Case of attribute used as actual for subprogram (positional) + + elsif (Nkind (Parnt) = N_Procedure_Call_Statement + or else + Nkind (Parnt) = N_Function_Call) + and then Is_Entity_Name (Name (Parnt)) + then + Must_Be_Imported (Entity (Name (Parnt))); + + -- Case of attribute used as actual for subprogram (named) + + elsif Nkind (Parnt) = N_Parameter_Association + and then (Nkind (GParnt) = N_Procedure_Call_Statement + or else + Nkind (GParnt) = N_Function_Call) + and then Is_Entity_Name (Name (GParnt)) + then + Must_Be_Imported (Entity (Name (GParnt))); + + -- Not an allowed case + + else + Bad_Null_Parameter + ("Null_Parameter must be actual or default parameter"); + end if; + + end Null_Parameter; + + ----------------- + -- Object_Size -- + ----------------- + + when Attribute_Object_Size => + Check_E0; + Check_Type; + Check_Not_Incomplete_Type; + Set_Etype (N, Universal_Integer); + + ------------ + -- Output -- + ------------ + + when Attribute_Output => + Check_E2; + Check_Stream_Attribute (TSS_Stream_Output); + Set_Etype (N, Standard_Void_Type); + Resolve (N, Standard_Void_Type); + + ------------------ + -- Partition_ID -- + ------------------ + + when Attribute_Partition_ID => + Check_E0; + + if P_Type /= Any_Type then + if not Is_Library_Level_Entity (Entity (P)) then + Error_Attr + ("prefix of % attribute must be library-level entity", P); + + -- The defining entity of prefix should not be declared inside + -- a Pure unit. RM E.1(8). + -- The Is_Pure flag has been set during declaration. + + elsif Is_Entity_Name (P) + and then Is_Pure (Entity (P)) + then + Error_Attr + ("prefix of % attribute must not be declared pure", P); + end if; + end if; + + Set_Etype (N, Universal_Integer); + + ------------------------- + -- Passed_By_Reference -- + ------------------------- + + when Attribute_Passed_By_Reference => + Check_E0; + Check_Type; + Set_Etype (N, Standard_Boolean); + + ------------------ + -- Pool_Address -- + ------------------ + + when Attribute_Pool_Address => + Check_E0; + Set_Etype (N, RTE (RE_Address)); + + --------- + -- Pos -- + --------- + + when Attribute_Pos => + Check_Discrete_Type; + Check_E1; + Resolve (E1, P_Base_Type); + Set_Etype (N, Universal_Integer); + + -------------- + -- Position -- + -------------- + + when Attribute_Position => + Check_Component; + Set_Etype (N, Universal_Integer); + + ---------- + -- Pred -- + ---------- + + when Attribute_Pred => + Check_Scalar_Type; + Check_E1; + Resolve (E1, P_Base_Type); + Set_Etype (N, P_Base_Type); + + -- Nothing to do for real type case + + if Is_Real_Type (P_Type) then + null; + + -- If not modular type, test for overflow check required + + else + if not Is_Modular_Integer_Type (P_Type) + and then not Range_Checks_Suppressed (P_Base_Type) + then + Enable_Range_Check (E1); + end if; + end if; + + ----------- + -- Range -- + ----------- + + when Attribute_Range => + Check_Array_Or_Scalar_Type; + + if Ada_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; + + ------------------ + -- Range_Length -- + ------------------ + + when Attribute_Range_Length => + 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); + + --------------- + -- Remainder -- + --------------- + + when Attribute_Remainder => + Check_Floating_Point_Type_2; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + Resolve (E2, P_Base_Type); + + ----------- + -- Round -- + ----------- + + when Attribute_Round => + Check_E1; + Check_Decimal_Fixed_Point_Type; + Set_Etype (N, P_Base_Type); + + -- Because the context is universal_real (3.5.10(12)) it is a legal + -- context for a universal fixed expression. This is the only + -- attribute whose functional description involves U_R. + + if Etype (E1) = Universal_Fixed then + declare + Conv : constant Node_Id := Make_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Universal_Real, Loc), + Expression => Relocate_Node (E1)); + + begin + Rewrite (E1, Conv); + Analyze (E1); + end; + end if; + + Resolve (E1, Any_Real); + + -------------- + -- Rounding -- + -------------- + + when Attribute_Rounding => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + --------------- + -- Safe_Emax -- + --------------- + + when Attribute_Safe_Emax => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Integer); + + ---------------- + -- Safe_First -- + ---------------- + + when Attribute_Safe_First => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Real); + + ---------------- + -- Safe_Large -- + ---------------- + + when Attribute_Safe_Large => + Check_E0; + Check_Real_Type; + Set_Etype (N, Universal_Real); + + --------------- + -- Safe_Last -- + --------------- + + when Attribute_Safe_Last => + Check_Floating_Point_Type_0; + Set_Etype (N, Universal_Real); + + ---------------- + -- Safe_Small -- + ---------------- + + when Attribute_Safe_Small => + Check_E0; + Check_Real_Type; + Set_Etype (N, Universal_Real); + + ----------- + -- Scale -- + ----------- + + when Attribute_Scale => + Check_E0; + Check_Decimal_Fixed_Point_Type; + Set_Etype (N, Universal_Integer); + + ------------- + -- Scaling -- + ------------- + + when Attribute_Scaling => + Check_Floating_Point_Type_2; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ------------------ + -- Signed_Zeros -- + ------------------ + + when Attribute_Signed_Zeros => + Check_Floating_Point_Type_0; + Set_Etype (N, Standard_Boolean); + + ---------- + -- Size -- + ---------- + + when Attribute_Size | Attribute_VADS_Size => + Check_E0; + + -- If 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 ("invalid prefix for % attribute", P); + end if; + + Check_Not_Incomplete_Type; + Set_Etype (N, Universal_Integer); + + ----------- + -- Small -- + ----------- + + when Attribute_Small => + Check_E0; + Check_Real_Type; + Set_Etype (N, Universal_Real); + + ------------------ + -- Storage_Pool -- + ------------------ + + when Attribute_Storage_Pool => + if Is_Access_Type (P_Type) then + Check_E0; + + -- Set appropriate entity + + if Present (Associated_Storage_Pool (Root_Type (P_Type))) then + Set_Entity (N, Associated_Storage_Pool (Root_Type (P_Type))); + else + Set_Entity (N, RTE (RE_Global_Pool_Object)); + end if; + + Set_Etype (N, Class_Wide_Type (RTE (RE_Root_Storage_Pool))); + + -- Validate_Remote_Access_To_Class_Wide_Type for attribute + -- Storage_Pool since this attribute is not defined for such + -- types (RM E.2.3(22)). + + Validate_Remote_Access_To_Class_Wide_Type (N); + + else + Error_Attr ("prefix of % attribute must be access type", P); + end if; + + ------------------ + -- Storage_Size -- + ------------------ + + when Attribute_Storage_Size => + + if Is_Task_Type (P_Type) then + Check_E0; + Set_Etype (N, Universal_Integer); + + elsif Is_Access_Type (P_Type) then + if Is_Entity_Name (P) + and then Is_Type (Entity (P)) + then + Check_E0; + Check_Type; + Set_Etype (N, Universal_Integer); + + -- Validate_Remote_Access_To_Class_Wide_Type for attribute + -- Storage_Size since this attribute is not defined for + -- such types (RM E.2.3(22)). + + Validate_Remote_Access_To_Class_Wide_Type (N); + + -- The prefix is allowed to be an implicit dereference + -- of an access value designating a task. + + else + Check_E0; + Check_Task_Prefix; + Set_Etype (N, Universal_Integer); + end if; + + else + Error_Attr + ("prefix of % attribute must be access or task type", P); + end if; + + ------------------ + -- Storage_Unit -- + ------------------ + + when Attribute_Storage_Unit => + Standard_Attribute (Ttypes.System_Storage_Unit); + + ----------------- + -- 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 ("invalid prefix for % attribute", P); + end if; + + ---------- + -- Succ -- + ---------- + + when Attribute_Succ => + Check_Scalar_Type; + Check_E1; + Resolve (E1, P_Base_Type); + Set_Etype (N, P_Base_Type); + + -- Nothing to do for real type case + + if Is_Real_Type (P_Type) then + null; + + -- If not modular type, test for overflow check required + + else + if not Is_Modular_Integer_Type (P_Type) + and then not Range_Checks_Suppressed (P_Base_Type) + then + Enable_Range_Check (E1); + end if; + end if; + + --------- + -- Tag -- + --------- + + when Attribute_Tag => + Check_E0; + Check_Dereference; + + if not Is_Tagged_Type (P_Type) then + Error_Attr ("prefix of % attribute must be tagged", P); + + -- Next test does not apply to generated code + -- why not, and what does the illegal reference mean??? + + elsif Is_Object_Reference (P) + and then not Is_Class_Wide_Type (P_Type) + and then Comes_From_Source (N) + then + Error_Attr + ("% attribute can only be applied to objects of class-wide type", + P); + end if; + + Set_Etype (N, RTE (RE_Tag)); + + ----------------- + -- Target_Name -- + ----------------- + + when Attribute_Target_Name => Target_Name : declare + TN : constant String := Sdefault.Target_Name.all; + TL : Natural; + + begin + Check_Standard_Prefix; + Check_E0; + + 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 ("prefix of %attribute must be System", P); + end if; + + Generate_Reference (RTE (RE_Address), P); + Analyze_And_Resolve (E1, Any_Integer); + Set_Etype (N, RTE (RE_Address)); + + ---------------- + -- Truncation -- + ---------------- + + when Attribute_Truncation => + Check_Floating_Point_Type_1; + Resolve (E1, P_Base_Type); + Set_Etype (N, P_Base_Type); + + ---------------- + -- Type_Class -- + ---------------- + + when Attribute_Type_Class => + Check_E0; + Check_Type; + Check_Not_Incomplete_Type; + Set_Etype (N, RTE (RE_Type_Class)); + + ----------------- + -- UET_Address -- + ----------------- + + when Attribute_UET_Address => + Check_E0; + Check_Unit_Name (P); + Set_Etype (N, RTE (RE_Address)); + + ----------------------- + -- Unbiased_Rounding -- + ----------------------- + + when Attribute_Unbiased_Rounding => + Check_Floating_Point_Type_1; + Set_Etype (N, P_Base_Type); + Resolve (E1, P_Base_Type); + + ---------------------- + -- Unchecked_Access -- + ---------------------- + + when Attribute_Unchecked_Access => + if Comes_From_Source (N) then + Check_Restriction (No_Unchecked_Access, N); + end if; + + 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 ("prefix for % attribute must be named number", P); + + else + declare + Expr : Node_Id; + Negative : Boolean; + S : Source_Ptr; + Src : Source_Buffer_Ptr; + + begin + Expr := Original_Node (Expression (Parent (Entity (P)))); + + if Nkind (Expr) = N_Op_Minus then + Negative := True; + Expr := Original_Node (Right_Opnd (Expr)); + else + Negative := False; + end if; + + if Nkind (Expr) /= N_Integer_Literal + and then Nkind (Expr) /= N_Real_Literal + then + Error_Attr + ("named number for % attribute must be simple literal", N); + end if; + + -- Build string literal corresponding to source literal text + + Start_String; + + if Negative then + Store_String_Char (Get_Char_Code ('-')); + end if; + + S := Sloc (Expr); + Src := Source_Text (Get_Source_File_Index (S)); + + while Src (S) /= ';' and then Src (S) /= ' ' loop + Store_String_Char (Get_Char_Code (Src (S))); + S := S + 1; + end loop; + + -- Now we rewrite the attribute with the string literal + + Rewrite (N, + Make_String_Literal (Loc, End_String)); + Analyze (N); + end; + end if; + end Universal_Literal_String; + + ------------------------- + -- Unrestricted_Access -- + ------------------------- + + -- This is a GNAT specific attribute which is like Access except that + -- all scope checks and checks for aliased views are omitted. + + when Attribute_Unrestricted_Access => + if Comes_From_Source (N) then + Check_Restriction (No_Unchecked_Access, N); + end if; + + if Is_Entity_Name (P) then + Set_Address_Taken (Entity (P)); + end if; + + Analyze_Access_Attribute; + + --------- + -- Val -- + --------- + + when Attribute_Val => Val : declare + begin + Check_E1; + Check_Discrete_Type; + Resolve (E1, Any_Integer); + Set_Etype (N, P_Base_Type); + + -- Note, we need a range check in general, but we wait for the + -- Resolve call to do this, since we want to let Eval_Attribute + -- have a chance to find an static illegality first! + end Val; + + ----------- + -- Valid -- + ----------- + + when Attribute_Valid => + Check_E0; + + -- Ignore check for object if we have a 'Valid reference generated + -- by the expanded code, since in some cases valid checks can occur + -- on items that are names, but are not objects (e.g. attributes). + + if Comes_From_Source (N) then + Check_Object_Reference (P); + end if; + + if not Is_Scalar_Type (P_Type) then + Error_Attr ("object for % attribute must be of scalar type", P); + end if; + + Set_Etype (N, Standard_Boolean); + + ----------- + -- Value -- + ----------- + + when Attribute_Value => Value : + begin + Check_E1; + Check_Scalar_Type; + + if Is_Enumeration_Type (P_Type) then + Check_Restriction (No_Enumeration_Maps, N); + end if; + + -- Set Etype before resolving expression because expansion of + -- expression may require enclosing type. 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_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_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_E0; + Check_Scalar_Type; + Set_Etype (N, Universal_Integer); + + ----------- + -- Width -- + ----------- + + when Attribute_Width => + Check_E0; + Check_Scalar_Type; + Set_Etype (N, Universal_Integer); + + --------------- + -- Word_Size -- + --------------- + + when Attribute_Word_Size => + Standard_Attribute (System_Word_Size); + + ----------- + -- Write -- + ----------- + + when Attribute_Write => + Check_E2; + Check_Stream_Attribute (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. + + function Aft_Value return Nat; + -- Computes Aft value for current attribute prefix (used by Aft itself + -- and also by Width for computing the Width of a fixed point type). + + procedure Check_Expressions; + -- In case where the attribute is not foldable, the expressions, if + -- any, of the attribute, are in a non-static context. This procedure + -- performs the required additional checks. + + 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. + + procedure Float_Attribute_Universal_Integer + (IEEES_Val : Int; + IEEEL_Val : Int; + IEEEX_Val : Int; + VAXFF_Val : Int; + VAXDF_Val : Int; + VAXGF_Val : Int; + AAMPS_Val : Int; + AAMPL_Val : Int); + -- This procedure evaluates a float attribute with no arguments that + -- returns a universal integer result. The parameters give the values + -- for the possible floating-point root types. See ttypef for details. + -- The prefix type is a float type (and is thus not a generic type). + + procedure Float_Attribute_Universal_Real + (IEEES_Val : String; + IEEEL_Val : String; + IEEEX_Val : String; + VAXFF_Val : String; + VAXDF_Val : String; + VAXGF_Val : String; + AAMPS_Val : String; + AAMPL_Val : String); + -- This procedure evaluates a float attribute with no arguments that + -- returns a universal real result. The parameters give the values + -- required for the possible floating-point root types in string + -- format as real literals with a possible leading minus sign. + -- The prefix type is a float type (and is thus not a generic type). + + function Fore_Value return Nat; + -- Computes the Fore value for the current attribute prefix, which is + -- known to be a static fixed-point type. Used by Fore and Width. + + function Mantissa return Uint; + -- Returns the Mantissa value for the prefix type + + procedure Set_Bounds; + -- Used for First, Last and Length attributes applied to an array or + -- array subtype. Sets the variables 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. 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). + + --------------- + -- Aft_Value -- + --------------- + + function Aft_Value return Nat is + Result : Nat; + Delta_Val : Ureal; + + begin + Result := 1; + Delta_Val := Delta_Value (P_Type); + + while Delta_Val < Ureal_Tenth loop + Delta_Val := Delta_Val * Ureal_10; + Result := Result + 1; + end loop; + + return Result; + end Aft_Value; + + ----------------------- + -- Check_Expressions -- + ----------------------- + + procedure Check_Expressions is + E : Node_Id := E1; + + begin + while Present (E) loop + Check_Non_Static_Context (E); + Next (E); + end loop; + end Check_Expressions; + + ---------------------------------- + -- Compile_Time_Known_Attribute -- + ---------------------------------- + + procedure Compile_Time_Known_Attribute (N : Node_Id; Val : Uint) is + T : constant Entity_Id := Etype (N); + + begin + Fold_Uint (N, Val, False); + + -- Check that result is in bounds of the type if it is static + + if Is_In_Range (N, T) then + null; + + elsif Is_Out_Of_Range (N, T) then + Apply_Compile_Time_Constraint_Error + (N, "value not in range of}?", 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; + + --------------------------------------- + -- Float_Attribute_Universal_Integer -- + --------------------------------------- + + procedure Float_Attribute_Universal_Integer + (IEEES_Val : Int; + IEEEL_Val : Int; + IEEEX_Val : Int; + VAXFF_Val : Int; + VAXDF_Val : Int; + VAXGF_Val : Int; + AAMPS_Val : Int; + AAMPL_Val : Int) + is + Val : Int; + Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type)); + + begin + if Vax_Float (P_Base_Type) then + if Digs = VAXFF_Digits then + Val := VAXFF_Val; + elsif Digs = VAXDF_Digits then + Val := VAXDF_Val; + else pragma Assert (Digs = VAXGF_Digits); + Val := VAXGF_Val; + end if; + + elsif Is_AAMP_Float (P_Base_Type) then + if Digs = AAMPS_Digits then + Val := AAMPS_Val; + else pragma Assert (Digs = AAMPL_Digits); + Val := AAMPL_Val; + end if; + + else + if Digs = IEEES_Digits then + Val := IEEES_Val; + elsif Digs = IEEEL_Digits then + Val := IEEEL_Val; + else pragma Assert (Digs = IEEEX_Digits); + Val := IEEEX_Val; + end if; + end if; + + Fold_Uint (N, UI_From_Int (Val), True); + end Float_Attribute_Universal_Integer; + + ------------------------------------ + -- Float_Attribute_Universal_Real -- + ------------------------------------ + + procedure Float_Attribute_Universal_Real + (IEEES_Val : String; + IEEEL_Val : String; + IEEEX_Val : String; + VAXFF_Val : String; + VAXDF_Val : String; + VAXGF_Val : String; + AAMPS_Val : String; + AAMPL_Val : String) + is + Val : Node_Id; + Digs : constant Nat := UI_To_Int (Digits_Value (P_Base_Type)); + + begin + if Vax_Float (P_Base_Type) then + if Digs = VAXFF_Digits then + Val := Real_Convert (VAXFF_Val); + elsif Digs = VAXDF_Digits then + Val := Real_Convert (VAXDF_Val); + else pragma Assert (Digs = VAXGF_Digits); + Val := Real_Convert (VAXGF_Val); + end if; + + elsif Is_AAMP_Float (P_Base_Type) then + if Digs = AAMPS_Digits then + Val := Real_Convert (AAMPS_Val); + else pragma Assert (Digs = AAMPL_Digits); + Val := Real_Convert (AAMPL_Val); + end if; + + else + if Digs = IEEES_Digits then + Val := Real_Convert (IEEES_Val); + elsif Digs = IEEEL_Digits then + Val := Real_Convert (IEEEL_Val); + else pragma Assert (Digs = IEEEX_Digits); + Val := Real_Convert (IEEEX_Val); + end if; + end if; + + Set_Sloc (Val, Loc); + Rewrite (N, Val); + Set_Is_Static_Expression (N, Static); + Analyze_And_Resolve (N, C_Type); + end Float_Attribute_Universal_Real; + + ---------------- + -- Fore_Value -- + ---------------- + + -- Note that the Fore calculation is based on the actual values + -- of the bounds, and does not take into account possible rounding. + + function Fore_Value return Nat is + Lo : constant Uint := Expr_Value (Type_Low_Bound (P_Type)); + Hi : constant Uint := Expr_Value (Type_High_Bound (P_Type)); + Small : constant Ureal := Small_Value (P_Type); + Lo_Real : constant Ureal := Lo * Small; + Hi_Real : constant Ureal := Hi * Small; + T : Ureal; + R : Nat; + + begin + -- Bounds are given in terms of small units, so first compute + -- proper values as reals. + + T := UR_Max (abs Lo_Real, abs Hi_Real); + R := 2; + + -- Loop to compute proper value if more than one digit required + + while T >= Ureal_10 loop + R := R + 1; + T := T / Ureal_10; + end loop; + + return R; + end Fore_Value; + + -------------- + -- Mantissa -- + -------------- + + -- Table of mantissa values accessed by function Computed using + -- the relation: + + -- T'Mantissa = integer next above (D * log(10)/log(2)) + 1) + + -- where D is T'Digits (RM83 3.5.7) + + Mantissa_Value : constant array (Nat range 1 .. 40) of Nat := ( + 1 => 5, + 2 => 8, + 3 => 11, + 4 => 15, + 5 => 18, + 6 => 21, + 7 => 25, + 8 => 28, + 9 => 31, + 10 => 35, + 11 => 38, + 12 => 41, + 13 => 45, + 14 => 48, + 15 => 51, + 16 => 55, + 17 => 58, + 18 => 61, + 19 => 65, + 20 => 68, + 21 => 71, + 22 => 75, + 23 => 78, + 24 => 81, + 25 => 85, + 26 => 88, + 27 => 91, + 28 => 95, + 29 => 98, + 30 => 101, + 31 => 104, + 32 => 108, + 33 => 111, + 34 => 114, + 35 => 118, + 36 => 121, + 37 => 124, + 38 => 128, + 39 => 131, + 40 => 134); + + function Mantissa return Uint is + begin + return + UI_From_Int (Mantissa_Value (UI_To_Int (Digits_Value (P_Type)))); + end Mantissa; + + ---------------- + -- Set_Bounds -- + ---------------- + + procedure Set_Bounds is + Ndim : Nat; + Indx : Node_Id; + Ityp : Entity_Id; + + begin + -- For a string literal subtype, we have to construct the bounds. + -- Valid Ada code never applies attributes to string literals, but + -- it is convenient to allow the expander to generate attribute + -- references of this type (e.g. First and Last applied to a string + -- literal). + + -- Note that the whole point of the E_String_Literal_Subtype is to + -- avoid this construction of bounds, but the cases in which we + -- have to materialize them are rare enough that we don't worry! + + -- The low bound is simply the low bound of the base type. The + -- high bound is computed from the length of the string and this + -- low bound. + + if Ekind (P_Type) = E_String_Literal_Subtype then + 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 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, 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; + + -- 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 Has_Discriminants, Type_Class, + -- and Unconstrained_Array. + + elsif (Id = Attribute_Definite + or else + Id = Attribute_Has_Access_Values + or else + Id = Attribute_Has_Discriminants + or else + Id = Attribute_Type_Class + or else + Id = Attribute_Unconstrained_Array) + 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 these three). + + 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. + + -- Definite, Has_Access_Values, Has_Discriminants, 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_Definite + or else + Id = Attribute_Has_Access_Values + or else + Id = Attribute_Has_Discriminants + or else + Id = Attribute_Type_Class + or else + Id = Attribute_Unconstrained_Array + or else + Id = Attribute_Component_Size + then + Static := False; + + else + 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). + + Static := Ada_Version >= Ada_95 + and then Statically_Denotes_Entity (P); + + declare + N : Node_Id; + + begin + N := First_Index (P_Type); + while Present (N) loop + Static := Static and then Is_Static_Subtype (Etype (N)); + + -- If however the index type is generic, attributes cannot + -- be folded. + + if Is_Generic_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. + + case Id is + + -------------- + -- Adjacent -- + -------------- + + when Attribute_Adjacent => + Fold_Ureal (N, + Eval_Fat.Adjacent + (P_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); + + --------- + -- Aft -- + --------- + + when Attribute_Aft => + Fold_Uint (N, UI_From_Int (Aft_Value), 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; + + --------- + -- 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_Root_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_Root_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_Root_Type, Expr_Value_R (E1), Expr_Value_R (E2)), Static); + + ----------- + -- Delta -- + ----------- + + when Attribute_Delta => + Fold_Ureal (N, Delta_Value (P_Type), True); + + -------------- + -- Definite -- + -------------- + + when Attribute_Definite => + Rewrite (N, New_Occurrence_Of ( + Boolean_Literals (not Is_Indefinite_Subtype (P_Entity)), Loc)); + Analyze_And_Resolve (N, Standard_Boolean); + + ------------ + -- Denorm -- + ------------ + + when Attribute_Denorm => + Fold_Uint + (N, UI_From_Int (Boolean'Pos (Denorm_On_Target)), True); + + ------------ + -- 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; + + ------------- + -- 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_Root_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; + end if; + end First_Attr; + + ----------------- + -- Fixed_Value -- + ----------------- + + when Attribute_Fixed_Value => + null; + + ----------- + -- Floor -- + ----------- + + when Attribute_Floor => + Fold_Ureal (N, + Eval_Fat.Floor (P_Root_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_Root_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); + + -------------- + -- Identity -- + -------------- + + when Attribute_Identity => + null; + + ----------- + -- Image -- + ----------- + + -- Image is a scalar attribute, but is never static, because it is + -- not a static function (having a non-scalar argument (RM 4.9(22)) + + when Attribute_Image => + null; + + --------- + -- Img -- + --------- + + -- Img is a scalar attribute, but is never static, because it is + -- not a static function (having a non-scalar argument (RM 4.9(22)) + + when Attribute_Img => + null; + + ------------------- + -- Integer_Value -- + ------------------- + + when Attribute_Integer_Value => + null; + + ----------- + -- Large -- + ----------- + + when Attribute_Large => + + -- For fixed-point, we use the identity: + + -- T'Large = (2.0**T'Mantissa - 1.0) * T'Small + + if Is_Fixed_Point_Type (P_Type) then + Rewrite (N, + Make_Op_Multiply (Loc, + Left_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => + Make_Op_Expon (Loc, + Left_Opnd => + Make_Real_Literal (Loc, Ureal_2), + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => P, + Attribute_Name => Name_Mantissa)), + Right_Opnd => Make_Real_Literal (Loc, Ureal_1)), + + Right_Opnd => + Make_Real_Literal (Loc, Small_Value (Entity (P))))); + + Analyze_And_Resolve (N, C_Type); + + -- Floating-point (Ada 83 compatibility) + + else + -- Ada 83 attribute is defined as (RM83 3.5.8) + + -- T'Large = 2.0**T'Emax * (1.0 - 2.0**(-T'Mantissa)) + + -- where + + -- T'Emax = 4 * T'Mantissa + + Fold_Ureal (N, + Ureal_2 ** (4 * Mantissa) * (Ureal_1 - Ureal_2 ** (-Mantissa)), + True); + end if; + + ---------- + -- Last -- + ---------- + + when Attribute_Last => Last : + begin + Set_Bounds; + + if Compile_Time_Known_Value (Hi_Bound) then + if Is_Real_Type (P_Type) then + Fold_Ureal (N, Expr_Value_R (Hi_Bound), Static); + else + Fold_Uint (N, Expr_Value (Hi_Bound), Static); + end if; + end if; + end Last; + + ------------------ + -- Leading_Part -- + ------------------ + + when Attribute_Leading_Part => + Fold_Ureal (N, + Eval_Fat.Leading_Part + (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); + + ------------ + -- Length -- + ------------ + + when Attribute_Length => Length : declare + Ind : Node_Id; + + begin + -- In the case of a generic index type, the bounds may + -- appear static but the computation is not meaningful, + -- and may generate a spurious warning. + + Ind := First_Index (P_Type); + + while Present (Ind) loop + if Is_Generic_Type (Etype (Ind)) then + return; + end if; + + Next_Index (Ind); + end loop; + + Set_Bounds; + + if Compile_Time_Known_Value (Lo_Bound) + and then Compile_Time_Known_Value (Hi_Bound) + then + Fold_Uint (N, + UI_Max (0, 1 + (Expr_Value (Hi_Bound) - Expr_Value (Lo_Bound))), + True); + end if; + end Length; + + ------------- + -- Machine -- + ------------- + + when Attribute_Machine => + Fold_Ureal (N, + Eval_Fat.Machine + (P_Root_Type, Expr_Value_R (E1), Eval_Fat.Round, N), + Static); + + ------------------ + -- Machine_Emax -- + ------------------ + + when Attribute_Machine_Emax => + Float_Attribute_Universal_Integer ( + IEEES_Machine_Emax, + IEEEL_Machine_Emax, + IEEEX_Machine_Emax, + VAXFF_Machine_Emax, + VAXDF_Machine_Emax, + VAXGF_Machine_Emax, + AAMPS_Machine_Emax, + AAMPL_Machine_Emax); + + ------------------ + -- Machine_Emin -- + ------------------ + + when Attribute_Machine_Emin => + Float_Attribute_Universal_Integer ( + IEEES_Machine_Emin, + IEEEL_Machine_Emin, + IEEEX_Machine_Emin, + VAXFF_Machine_Emin, + VAXDF_Machine_Emin, + VAXGF_Machine_Emin, + AAMPS_Machine_Emin, + AAMPL_Machine_Emin); + + ---------------------- + -- Machine_Mantissa -- + ---------------------- + + when Attribute_Machine_Mantissa => + Float_Attribute_Universal_Integer ( + IEEES_Machine_Mantissa, + IEEEL_Machine_Mantissa, + IEEEX_Machine_Mantissa, + VAXFF_Machine_Mantissa, + VAXDF_Machine_Mantissa, + VAXGF_Machine_Mantissa, + AAMPS_Machine_Mantissa, + AAMPL_Machine_Mantissa); + + ----------------------- + -- Machine_Overflows -- + ----------------------- + + when Attribute_Machine_Overflows => + + -- Always true for fixed-point + + if Is_Fixed_Point_Type (P_Type) then + Fold_Uint (N, True_Value, 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_Root_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_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_Root_Type, Expr_Value_R (E1)), Static); + + ---------------- + -- Model_Emin -- + ---------------- + + when Attribute_Model_Emin => + Float_Attribute_Universal_Integer ( + IEEES_Model_Emin, + IEEEL_Model_Emin, + IEEEX_Model_Emin, + VAXFF_Model_Emin, + VAXDF_Model_Emin, + VAXGF_Model_Emin, + AAMPS_Model_Emin, + AAMPL_Model_Emin); + + ------------------- + -- Model_Epsilon -- + ------------------- + + when Attribute_Model_Epsilon => + Float_Attribute_Universal_Real ( + IEEES_Model_Epsilon'Universal_Literal_String, + IEEEL_Model_Epsilon'Universal_Literal_String, + IEEEX_Model_Epsilon'Universal_Literal_String, + VAXFF_Model_Epsilon'Universal_Literal_String, + VAXDF_Model_Epsilon'Universal_Literal_String, + VAXGF_Model_Epsilon'Universal_Literal_String, + AAMPS_Model_Epsilon'Universal_Literal_String, + AAMPL_Model_Epsilon'Universal_Literal_String); + + -------------------- + -- Model_Mantissa -- + -------------------- + + when Attribute_Model_Mantissa => + Float_Attribute_Universal_Integer ( + IEEES_Model_Mantissa, + IEEEL_Model_Mantissa, + IEEEX_Model_Mantissa, + VAXFF_Model_Mantissa, + VAXDF_Model_Mantissa, + VAXGF_Model_Mantissa, + AAMPS_Model_Mantissa, + AAMPL_Model_Mantissa); + + ----------------- + -- Model_Small -- + ----------------- + + when Attribute_Model_Small => + Float_Attribute_Universal_Real ( + IEEES_Model_Small'Universal_Literal_String, + IEEEL_Model_Small'Universal_Literal_String, + IEEEX_Model_Small'Universal_Literal_String, + VAXFF_Model_Small'Universal_Literal_String, + VAXDF_Model_Small'Universal_Literal_String, + VAXGF_Model_Small'Universal_Literal_String, + AAMPS_Model_Small'Universal_Literal_String, + AAMPL_Model_Small'Universal_Literal_String); + + ------------- + -- 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; + + ------------------------- + -- 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_Root_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; + + 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; + + --------------- + -- 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_Root_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_Root_Type, Expr_Value_R (E1)), Static); + + --------------- + -- Safe_Emax -- + --------------- + + when Attribute_Safe_Emax => + Float_Attribute_Universal_Integer ( + IEEES_Safe_Emax, + IEEEL_Safe_Emax, + IEEEX_Safe_Emax, + VAXFF_Safe_Emax, + VAXDF_Safe_Emax, + VAXGF_Safe_Emax, + AAMPS_Safe_Emax, + AAMPL_Safe_Emax); + + ---------------- + -- Safe_First -- + ---------------- + + when Attribute_Safe_First => + Float_Attribute_Universal_Real ( + IEEES_Safe_First'Universal_Literal_String, + IEEEL_Safe_First'Universal_Literal_String, + IEEEX_Safe_First'Universal_Literal_String, + VAXFF_Safe_First'Universal_Literal_String, + VAXDF_Safe_First'Universal_Literal_String, + VAXGF_Safe_First'Universal_Literal_String, + AAMPS_Safe_First'Universal_Literal_String, + AAMPL_Safe_First'Universal_Literal_String); + + ---------------- + -- Safe_Large -- + ---------------- + + when Attribute_Safe_Large => + if Is_Fixed_Point_Type (P_Type) then + Fold_Ureal + (N, Expr_Value_R (Type_High_Bound (P_Base_Type)), Static); + else + Float_Attribute_Universal_Real ( + IEEES_Safe_Large'Universal_Literal_String, + IEEEL_Safe_Large'Universal_Literal_String, + IEEEX_Safe_Large'Universal_Literal_String, + VAXFF_Safe_Large'Universal_Literal_String, + VAXDF_Safe_Large'Universal_Literal_String, + VAXGF_Safe_Large'Universal_Literal_String, + AAMPS_Safe_Large'Universal_Literal_String, + AAMPL_Safe_Large'Universal_Literal_String); + end if; + + --------------- + -- Safe_Last -- + --------------- + + when Attribute_Safe_Last => + Float_Attribute_Universal_Real ( + IEEES_Safe_Last'Universal_Literal_String, + IEEEL_Safe_Last'Universal_Literal_String, + IEEEX_Safe_Last'Universal_Literal_String, + VAXFF_Safe_Last'Universal_Literal_String, + VAXDF_Safe_Last'Universal_Literal_String, + VAXGF_Safe_Last'Universal_Literal_String, + AAMPS_Safe_Last'Universal_Literal_String, + AAMPL_Safe_Last'Universal_Literal_String); + + ---------------- + -- Safe_Small -- + ---------------- + + when Attribute_Safe_Small => + + -- In Ada 95, the old Ada 83 attribute Safe_Small is redundant + -- for fixed-point, since is the same as Small, but we implement + -- it for backwards compatibility. + + if Is_Fixed_Point_Type (P_Type) then + Fold_Ureal (N, Small_Value (P_Type), Static); + + -- Ada 83 Safe_Small for floating-point cases + + else + Float_Attribute_Universal_Real ( + IEEES_Safe_Small'Universal_Literal_String, + IEEEL_Safe_Small'Universal_Literal_String, + IEEEX_Safe_Small'Universal_Literal_String, + VAXFF_Safe_Small'Universal_Literal_String, + VAXDF_Safe_Small'Universal_Literal_String, + VAXGF_Safe_Small'Universal_Literal_String, + AAMPS_Safe_Small'Universal_Literal_String, + AAMPL_Safe_Small'Universal_Literal_String); + end if; + + ----------- + -- Scale -- + ----------- + + when Attribute_Scale => + Fold_Uint (N, Scale_Value (P_Type), True); + + ------------- + -- Scaling -- + ------------- + + when Attribute_Scaling => + Fold_Ureal (N, + Eval_Fat.Scaling + (P_Root_Type, Expr_Value_R (E1), Expr_Value (E2)), Static); + + ------------------ + -- Signed_Zeros -- + ------------------ + + when Attribute_Signed_Zeros => + Fold_Uint + (N, UI_From_Int (Boolean'Pos (Signed_Zeros_On_Target)), 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 compatability. + -- 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_Root_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_Root_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_Clas would not meet this requirement. + + elsif Is_Protected_Type (Typ) then + Id := RE_Type_Class_Task; + + -- Not clear if there are any other possibilities, but if there + -- are, then we will treat them as the address case. + + else + Id := RE_Type_Class_Address; + end if; + + Rewrite (N, New_Occurrence_Of (RTE (Id), Loc)); + end Type_Class; + + ----------------------- + -- Unbiased_Rounding -- + ----------------------- + + when Attribute_Unbiased_Rounding => + Fold_Ureal (N, + Eval_Fat.Unbiased_Rounding (P_Root_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; + + --------------- + -- 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), 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 R = Standard_Character + or else R = Standard_Wide_Character + or else R = Standard_Wide_Wide_Character + 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 + W := 12; + + else + C := Character'Val (J); + + -- Test for all cases where Character'Image + -- yields an image that is longer than three + -- characters. First the cases of Reserved_xxx + -- names (length = 12). + + case C is + when Reserved_128 | Reserved_129 | + Reserved_132 | Reserved_153 + + => Wt := 12; + + when BS | HT | LF | VT | FF | CR | + SO | SI | EM | FS | GS | RS | + US | RI | MW | ST | PM + + => Wt := 2; + + when NUL | SOH | STX | ETX | EOT | + ENQ | ACK | BEL | DLE | DC1 | + DC2 | DC3 | DC4 | NAK | SYN | + ETB | CAN | SUB | ESC | DEL | + BPH | NBH | NEL | SSA | ESA | + HTS | HTJ | VTS | PLD | PLU | + SS2 | SS3 | DCS | PU1 | PU2 | + STS | CCH | SPA | EPA | SOS | + SCI | CSI | OSC | APC + + => Wt := 3; + + when Space .. Tilde | + No_Break_Space .. LC_Y_Diaeresis + + => Wt := 3; + end case; + + W := Int'Max (W, Wt); + end if; + end loop; + + -- Width for types derived from Standard.Boolean + + elsif R = Standard_Boolean then + if Lo = 0 then + W := 5; -- FALSE + else + W := 4; -- TRUE + end if; + + -- Width for integer types + + elsif Is_Integer_Type (P_Type) then + T := UI_Max (abs Lo, abs Hi); + + W := 2; + while T >= 10 loop + W := W + 1; + T := T / 10; + end loop; + + -- Only remaining possibility is user declared enum type + + else + pragma Assert (Is_Enumeration_Type (P_Type)); + + W := 0; + L := First_Literal (P_Type); + + while Present (L) loop + + -- Only pay attention to in range characters + + if Lo <= Enumeration_Pos (L) + and then Enumeration_Pos (L) <= Hi + then + -- For Width case, use decoded name + + if Id = Attribute_Width then + Get_Decoded_Name_String (Chars (L)); + Wt := Nat (Name_Len); + + -- For Wide_[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 can never be folded, and furthermore we + -- should not even have entered the case statement for any of these. + -- Note that in some cases, the values have already been folded as + -- a result of the processing in Analyze_Attribute. + + when Attribute_Abort_Signal | + Attribute_Access | + Attribute_Address | + Attribute_Address_Size | + Attribute_Asm_Input | + Attribute_Asm_Output | + Attribute_Base | + Attribute_Bit_Order | + Attribute_Bit_Position | + Attribute_Callable | + Attribute_Caller | + Attribute_Class | + Attribute_Code_Address | + Attribute_Count | + Attribute_Default_Bit_Order | + Attribute_Elaborated | + Attribute_Elab_Body | + Attribute_Elab_Spec | + Attribute_External_Tag | + Attribute_First_Bit | + Attribute_Input | + Attribute_Last_Bit | + Attribute_Maximum_Alignment | + Attribute_Output | + Attribute_Partition_ID | + Attribute_Pool_Address | + Attribute_Position | + Attribute_Read | + Attribute_Storage_Pool | + Attribute_Storage_Size | + Attribute_Storage_Unit | + Attribute_Tag | + Attribute_Target_Name | + Attribute_Terminated | + Attribute_To_Address | + Attribute_UET_Address | + Attribute_Unchecked_Access | + Attribute_Universal_Literal_String | + Attribute_Unrestricted_Access | + Attribute_Valid | + Attribute_Value | + Attribute_Wchar_T_Size | + Attribute_Wide_Value | + Attribute_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 (N) = N_Integer_Literal + or else Nkind (N) = N_Real_Literal + or else Nkind (N) = N_Character_Literal + or else Nkind (N) = N_String_Literal + or else (Is_Entity_Name (N) + and then Ekind (Entity (N)) = E_Enumeration_Literal) + then + Set_Is_Static_Expression (N, Static); + + -- If this is still an attribute reference, then it has not been folded + -- and that means that its expressions are in a non-static context. + + elsif Nkind (N) = N_Attribute_Reference then + Check_Expressions; + + -- Note: the else case not covered here are odd cases where the + -- processing has transformed the attribute into something other + -- than a constant. Nothing more to do in such cases. + + else + null; + end if; + + end Eval_Attribute; + + ------------------------------ + -- Is_Anonymous_Tagged_Base -- + ------------------------------ + + function Is_Anonymous_Tagged_Base + (Anon : Entity_Id; + Typ : Entity_Id) + return Boolean + is + begin + return + Anon = Current_Scope + and then Is_Itype (Anon) + and then Associated_Node_For_Itype (Anon) = Parent (Typ); + end Is_Anonymous_Tagged_Base; + + ----------------------- + -- Resolve_Attribute -- + ----------------------- + + procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + P : constant Node_Id := Prefix (N); + Aname : constant Name_Id := Attribute_Name (N); + Attr_Id : constant Attribute_Id := Get_Attribute_Id (Aname); + Btyp : constant Entity_Id := Base_Type (Typ); + 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_N + ("?non-local pointer cannot point to local object", P); + Error_Msg_N + ("\?Program_Error will be raised at run time", P); + Rewrite (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Accessibility_Check_Failed)); + Set_Etype (N, Typ); + return; + + else + Error_Msg_N + ("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 (Parent (N)) = N_Discriminant_Association + or else + Nkind (Parent (N)) = 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 + -- indices than nothing at all (see Check_Array_Type). + + if Error_Posted (N) + and then Attr_Id /= Attribute_First + and then Attr_Id /= Attribute_Last + and then Attr_Id /= Attribute_Length + and then Attr_Id /= Attribute_Range + then + return; + end if; + + -- If attribute was universal type, reset to actual type + + if Etype (N) = Universal_Integer + or else Etype (N) = Universal_Real + then + Set_Etype (N, Typ); + end if; + + -- Remaining processing depends on attribute + + case Attr_Id is + + ------------ + -- Access -- + ------------ + + -- For access attributes, if the prefix denotes an entity, it is + -- interpreted as a name, never as a call. It may be overloaded, + -- in which case resolution uses the profile of the context type. + -- Otherwise prefix must be resolved. + + when Attribute_Access + | Attribute_Unchecked_Access + | Attribute_Unrestricted_Access => + + if Is_Variable (P) then + Note_Possible_Modification (P); + end if; + + if Is_Entity_Name (P) then + if Is_Overloaded (P) then + Get_First_Interp (P, Index, It); + + while Present (It.Nam) loop + + if Type_Conformant (Designated_Type (Typ), It.Nam) then + Set_Entity (P, It.Nam); + + -- The prefix is definitely NOT overloaded anymore + -- at this point, so we reset the Is_Overloaded + -- flag to avoid any confusion when reanalyzing + -- the node. + + Set_Is_Overloaded (P, False); + Generate_Reference (Entity (P), P); + exit; + end if; + + Get_Next_Interp (Index, It); + end loop; + + -- If it is a subprogram name or a type, there is nothing + -- to resolve. + + elsif not Is_Overloadable (Entity (P)) + and then not Is_Type (Entity (P)) + then + Resolve (P); + end if; + + Error_Msg_Name_1 := Aname; + + if not Is_Entity_Name (P) then + null; + + elsif Is_Abstract (Entity (P)) + and then Is_Overloadable (Entity (P)) + then + Error_Msg_N ("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_N + ("prefix of % attribute cannot be enumeration literal", + P); + else + Error_Msg_N + ("prefix of % attribute cannot be intrinsic", P); + end if; + + Set_Etype (N, Any_Type); + + elsif Is_Thread_Body (Entity (P)) then + Error_Msg_N + ("prefix of % attribute cannot be a thread body", P); + end if; + + -- Assignments, return statements, components of aggregates, + -- generic instantiations will require convention checks if + -- the type is an access to subprogram. Given that there will + -- also be accessibility checks on those, this is where the + -- checks can eventually be centralized ??? + + if Ekind (Btyp) = E_Access_Subprogram_Type + or else + Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type + or else + Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type + then + if Convention (Btyp) /= Convention (Entity (P)) then + Error_Msg_N + ("subprogram has invalid convention for context", P); + + else + Check_Subtype_Conformant + (New_Id => Entity (P), + Old_Id => Designated_Type (Btyp), + Err_Loc => P); + end if; + + if Attr_Id = Attribute_Unchecked_Access then + Error_Msg_Name_1 := Aname; + Error_Msg_N + ("attribute% cannot be applied to a subprogram", P); + + elsif Aname = Name_Unrestricted_Access then + null; -- Nothing to check + + -- Check the static accessibility rule of 3.10.2(32). + -- This rule also applies within the private part of an + -- instantiation. This rule does not apply to anonymous + -- access-to-subprogram types (Ada 2005). + + elsif Attr_Id = Attribute_Access + and then not In_Instance_Body + 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 + Error_Msg_N + ("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 attibute 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. + + elsif Attr_Id = Attribute_Access + 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 + if Root_Type (Btyp) = Btyp then + Error_Msg_N + ("access type must not be outside generic unit", + N); + else + Error_Msg_N + ("ancestor access type must not be outside " & + "generic unit", N); + end if; + + -- 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. + + if Is_Entity_Name (P) + and then Is_Overloadable (Entity (P)) + and then Present (Alias (Entity (P))) + then + Rewrite (P, + New_Occurrence_Of (Alias (Entity (P)), Sloc (P))); + end if; + + elsif Nkind (P) = N_Selected_Component + and then Is_Overloadable (Entity (Selector_Name (P))) + then + -- Protected operation. If operation is overloaded, must + -- disambiguate. Prefix that denotes protected object itself + -- is resolved with its own type. + + if Attr_Id = Attribute_Unchecked_Access then + Error_Msg_Name_1 := Aname; + Error_Msg_N + ("attribute% cannot be applied to protected operation", P); + end if; + + Resolve (Prefix (P)); + 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 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 Comes_From_Source (N) then + Error_Msg_N ("access-to-variable designates constant", P); + end if; + end if; + + if (Attr_Id = Attribute_Access + or else + Attr_Id = Attribute_Unchecked_Access) + and then (Ekind (Btyp) = E_General_Access_Type + or else Ekind (Btyp) = E_Anonymous_Access_Type) + then + -- Ada 2005 (AI-230): Check the accessibility of anonymous + -- access types in record and array components. For a + -- component definition the level is the same of the + -- enclosing composite type. + + if Ada_Version >= Ada_05 + and then Is_Local_Anonymous_Access (Btyp) + and then Object_Access_Level (P) > Type_Access_Level (Btyp) + then + -- In an instance, this is a runtime check, but one we + -- know will fail, so generate an appropriate warning. + + if In_Instance_Body then + Error_Msg_N + ("?non-local pointer cannot point to local object", P); + Error_Msg_N + ("\?Program_Error will be raised at run time", P); + Rewrite (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Accessibility_Check_Failed)); + Set_Etype (N, Typ); + else + Error_Msg_N + ("non-local pointer cannot point to local object", P); + end if; + end if; + + if Is_Dependent_Component_Of_Mutable_Object (P) then + Error_Msg_N + ("illegal attribute for discriminant-dependent component", + P); + end if; + + -- Check the static matching rule of 3.10.2(27). The + -- nominal subtype of the prefix must statically + -- match the designated type. + + Nom_Subt := Etype (P); + + if Is_Constr_Subt_For_U_Nominal (Nom_Subt) then + Nom_Subt := Etype (Nom_Subt); + end if; + + if Is_Tagged_Type (Designated_Type (Typ)) then + + -- If the attribute is in the context of an access + -- parameter, then the prefix is allowed to be of + -- the class-wide type (by AI-127). + + if Ekind (Typ) = E_Anonymous_Access_Type then + if not Covers (Designated_Type (Typ), Nom_Subt) + and then not Covers (Nom_Subt, Designated_Type (Typ)) + then + declare + Desig : Entity_Id; + + begin + Desig := Designated_Type (Typ); + + if Is_Class_Wide_Type (Desig) then + Desig := Etype (Desig); + end if; + + if Is_Anonymous_Tagged_Base (Nom_Subt, Desig) then + null; + + else + Error_Msg_NE + ("type of prefix: & not compatible", + P, Nom_Subt); + Error_Msg_NE + ("\with &, the expected designated type", + P, Designated_Type (Typ)); + end if; + end; + end if; + + elsif not Covers (Designated_Type (Typ), Nom_Subt) + or else + (not Is_Class_Wide_Type (Designated_Type (Typ)) + and then Is_Class_Wide_Type (Nom_Subt)) + then + Error_Msg_NE + ("type of prefix: & is not covered", P, Nom_Subt); + Error_Msg_NE + ("\by &, the expected designated type" & + " ('R'M 3.10.2 (27))", P, Designated_Type (Typ)); + end if; + + if Is_Class_Wide_Type (Designated_Type (Typ)) + and then Has_Discriminants (Etype (Designated_Type (Typ))) + and then Is_Constrained (Etype (Designated_Type (Typ))) + and then Designated_Type (Typ) /= Nom_Subt + then + Apply_Discriminant_Check + (N, Etype (Designated_Type (Typ))); + end if; + + elsif not Subtypes_Statically_Match + (Designated_Type (Base_Type (Typ)), Nom_Subt) + and then + not (Has_Discriminants (Designated_Type (Typ)) + and then + not Is_Constrained + (Designated_Type (Base_Type (Typ)))) + then + Error_Msg_N + ("object subtype must statically match " + & "designated subtype", P); + + if Is_Entity_Name (P) + and then Is_Array_Type (Designated_Type (Typ)) + then + + declare + D : constant Node_Id := Declaration_Node (Entity (P)); + + begin + Error_Msg_N ("aliased object has explicit bounds?", + D); + Error_Msg_N ("\declare without bounds" + & " (and with explicit initialization)?", D); + Error_Msg_N ("\for use with unconstrained access?", D); + end; + end if; + end if; + + -- Check the static accessibility rule of 3.10.2(28). + -- Note that this check is not performed for the + -- case of an anonymous access type, since the access + -- attribute is always legal in such a context. + + if Attr_Id /= Attribute_Unchecked_Access + and then Object_Access_Level (P) > Type_Access_Level (Btyp) + and then Ekind (Btyp) = E_General_Access_Type + then + Accessibility_Message; + return; + end if; + end if; + + if Ekind (Btyp) = E_Access_Protected_Subprogram_Type + or else + Ekind (Btyp) = E_Anonymous_Access_Protected_Subprogram_Type + then + if Is_Entity_Name (P) + and then not Is_Protected_Type (Scope (Entity (P))) + then + Error_Msg_N ("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. + + elsif Object_Access_Level (P) > Type_Access_Level (Btyp) + and then Comes_From_Source (N) + and then Ekind (Btyp) = E_Access_Protected_Subprogram_Type + and then No (Original_Access_Type (Typ)) + then + Accessibility_Message; + return; + end if; + + elsif (Ekind (Btyp) = E_Access_Subprogram_Type + or else + Ekind (Btyp) = E_Anonymous_Access_Subprogram_Type) + and then Ekind (Etype (N)) = E_Access_Protected_Subprogram_Type + then + Error_Msg_N ("context requires a non-protected subprogram", P); + end if; + + -- The context cannot be a pool-specific type, but this is a + -- legality rule, not a resolution rule, so it must be checked + -- separately, after possibly disambiguation (see AI-245). + + if Ekind (Btyp) = E_Access_Type + and then Attr_Id /= Attribute_Unrestricted_Access + then + Wrong_Type (N, Typ); + end if; + + Set_Etype (N, Typ); + + -- Check for incorrect atomic/volatile reference (RM C.6(12)) + + if Attr_Id /= Attribute_Unrestricted_Access then + if Is_Atomic_Object (P) + and then not Is_Atomic (Designated_Type (Typ)) + then + Error_Msg_N + ("access to atomic object cannot yield access-to-" & + "non-atomic type", P); + + elsif Is_Volatile_Object (P) + and then not Is_Volatile (Designated_Type (Typ)) + then + Error_Msg_N + ("access to volatile object cannot yield access-to-" & + "non-volatile type", P); + end if; + end if; + + ------------- + -- Address -- + ------------- + + -- Deal with resolving the type for Address attribute, overloading + -- is not permitted here, since there is no context to resolve it. + + when Attribute_Address | Attribute_Code_Address => + + -- To be safe, assume that if the address of a variable is taken, + -- it may be modified via this address, so note modification. + + if Is_Variable (P) then + Note_Possible_Modification (P); + end if; + + if Nkind (P) in N_Subexpr + and then Is_Overloaded (P) + then + Get_First_Interp (P, Index, It); + Get_Next_Interp (Index, It); + + if Present (It.Nam) then + Error_Msg_Name_1 := Aname; + Error_Msg_N + ("prefix of % attribute cannot be overloaded", P); + return; + end if; + end if; + + if not Is_Entity_Name (P) + or else not Is_Overloadable (Entity (P)) + then + if not Is_Task_Type (Etype (P)) + or else Nkind (P) = N_Explicit_Dereference + then + Resolve (P); + end if; + end if; + + -- If this is the name of a derived subprogram, or that of a + -- generic actual, the address is that of the original entity. + + if Is_Entity_Name (P) + and then Is_Overloadable (Entity (P)) + and then Present (Alias (Entity (P))) + then + Rewrite (P, + New_Occurrence_Of (Alias (Entity (P)), Sloc (P))); + end if; + + --------------- + -- AST_Entry -- + --------------- + + -- Prefix of the AST_Entry attribute is an entry name which must + -- not be resolved, since this is definitely not an entry call. + + when Attribute_AST_Entry => + null; + + ------------------ + -- Body_Version -- + ------------------ + + -- Prefix of Body_Version attribute can be a subprogram name which + -- must not be resolved, since this is not a call. + + when Attribute_Body_Version => + null; + + ------------ + -- Caller -- + ------------ + + -- Prefix of Caller attribute is an entry name which must not + -- be resolved, since this is definitely not an entry call. + + when Attribute_Caller => + null; + + ------------------ + -- Code_Address -- + ------------------ + + -- Shares processing with Address attribute + + ----------- + -- Count -- + ----------- + + -- 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; + + -------------------- + -- 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; + + 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; + + function Check_Discriminated_Prival + (N : Node_Id) + return Node_Id; + -- The range of a private component constrained by a + -- discriminant is rewritten to make the discriminant + -- explicit. This solves some complex visibility problems + -- related to the use of privals. + + -------------------------------- + -- Check_Discriminated_Prival -- + -------------------------------- + + function Check_Discriminated_Prival + (N : Node_Id) + return Node_Id + is + begin + if Is_Entity_Name (N) + and then Ekind (Entity (N)) = E_In_Parameter + and then not Within_Init_Proc + then + return Make_Identifier (Sloc (N), Chars (Entity (N))); + else + return Duplicate_Subexpr (N); + end if; + end Check_Discriminated_Prival; + + -- Start of processing for Range_Attribute + + begin + if not Is_Entity_Name (P) + or else not Is_Type (Entity (P)) + then + Resolve (P); + end if; + + -- Check whether prefix is (renaming of) private component + -- of protected type. + + if Is_Entity_Name (P) + and then Comes_From_Source (N) + and then Is_Array_Type (Etype (P)) + and then Number_Dimensions (Etype (P)) = 1 + and then (Ekind (Scope (Entity (P))) = E_Protected_Type + or else + Ekind (Scope (Scope (Entity (P)))) = + E_Protected_Type) + then + LB := + Check_Discriminated_Prival + (Type_Low_Bound (Etype (First_Index (Etype (P))))); + + HB := + Check_Discriminated_Prival + (Type_High_Bound (Etype (First_Index (Etype (P))))); + + else + HB := + Make_Attribute_Reference (Loc, + Prefix => Duplicate_Subexpr (P), + Attribute_Name => Name_Last, + Expressions => Expressions (N)); + + LB := + Make_Attribute_Reference (Loc, + Prefix => P, + Attribute_Name => Name_First, + Expressions => Expressions (N)); + end if; + + -- If the original was marked as Must_Not_Freeze (see code + -- in Sem_Ch3.Make_Index), then make sure the rewriting + -- does not freeze either. + + if Must_Not_Freeze (N) then + Set_Must_Not_Freeze (HB); + Set_Must_Not_Freeze (LB); + Set_Must_Not_Freeze (Prefix (HB)); + Set_Must_Not_Freeze (Prefix (LB)); + end if; + + if Raises_Constraint_Error (Prefix (N)) then + + -- Preserve Sloc of prefix in the new bounds, so that + -- the posted warning can be removed if we are within + -- unreachable code. + + Set_Sloc (LB, Sloc (Prefix (N))); + Set_Sloc (HB, Sloc (Prefix (N))); + end if; + + Rewrite (N, Make_Range (Loc, LB, HB)); + Analyze_And_Resolve (N, Typ); + + -- Normally after resolving attribute nodes, Eval_Attribute + -- is called to do any possible static evaluation of the node. + -- However, here since the Range attribute has just been + -- transformed into a range expression it is no longer an + -- attribute node and therefore the call needs to be avoided + -- and is accomplished by simply returning from the procedure. + + return; + end Range_Attribute; + + ----------------- + -- UET_Address -- + ----------------- + + -- Prefix must not be resolved in this case, since it is not a + -- real entity reference. No action of any kind is require! + + when Attribute_UET_Address => + return; + + ---------------------- + -- Unchecked_Access -- + ---------------------- + + -- Processing is shared with Access + + ------------------------- + -- Unrestricted_Access -- + ------------------------- + + -- Processing is shared with Access + + --------- + -- Val -- + --------- + + -- Apply range check. Note that we did not do this during the + -- analysis phase, since we wanted Eval_Attribute to have a + -- chance at finding an illegal out of range value. + + when Attribute_Val => + + -- Note that we do our own Eval_Attribute call here rather than + -- use the common one, because we need to do processing after + -- the call, as per above comment. + + Eval_Attribute (N); + + -- Eval_Attribute may replace the node with a raise CE, or + -- fold it to a constant. Obviously we only apply a scalar + -- range check if this did not happen! + + if Nkind (N) = N_Attribute_Reference + and then Attribute_Name (N) = Name_Val + then + Apply_Scalar_Range_Check (First (Expressions (N)), Btyp); + end if; + + return; + + ------------- + -- Version -- + ------------- + + -- Prefix of Version attribute can be a subprogram name which + -- must not be resolved, since this is not a call. + + when Attribute_Version => + null; + + ---------------------- + -- Other Attributes -- + ---------------------- + + -- For other attributes, resolve prefix unless it is a type. If + -- the attribute reference itself is a type name ('Base and 'Class) + -- then this is only legal within a task or protected record. + + when others => + if not Is_Entity_Name (P) + or else not Is_Type (Entity (P)) + then + Resolve (P); + 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; + end case; + + -- Normally the Freezing is done by Resolve but sometimes the Prefix + -- is not resolved, in which case the freezing must be done now. + + Freeze_Expression (P); + + -- Finally perform static evaluation on the attribute reference + + Eval_Attribute (N); + end Resolve_Attribute; + + -------------------------------- + -- 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; + + function Has_Specified_Stream_Attribute + (Typ : Entity_Id; + Nam : TSS_Name_Type) return Boolean; + -- True iff there is a visible attribute definition clause specifying + -- attribute Nam for Typ. + + ------------------------------------ + -- Has_Specified_Stream_Attribute -- + ------------------------------------ + + function Has_Specified_Stream_Attribute + (Typ : Entity_Id; + Nam : TSS_Name_Type) return Boolean + is + begin + return False + or else + (Nam = TSS_Stream_Input + and then Has_Specified_Stream_Input (Typ)) + or else + (Nam = TSS_Stream_Output + and then Has_Specified_Stream_Output (Typ)) + or else + (Nam = TSS_Stream_Read + and then Has_Specified_Stream_Read (Typ)) + or else + (Nam = TSS_Stream_Write + and then Has_Specified_Stream_Write (Typ)); + end Has_Specified_Stream_Attribute; + + -- Start of processing for Stream_Attribute_Available + + begin + -- We need some comments in this body ??? + + if Has_Specified_Stream_Attribute (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 (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_05 + and then Stream_Attribute_Available (Etyp, TSS_Stream_Read) + then + return True; + + elsif Nam = TSS_Stream_Output + and then Ada_Version >= Ada_05 + 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_Specified_Stream_Attribute (Etyp, Nam) then + return True; + end if; + end loop; + + if Ada_Version < Ada_05 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; |