------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 1 3 -- -- -- -- B o d y -- -- -- -- -- -- Copyright (C) 1992-2002, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Atree; use Atree; with Checks; use Checks; with Einfo; use Einfo; with Errout; use Errout; with Exp_Tss; use Exp_Tss; with Exp_Util; use Exp_Util; with Hostparm; use Hostparm; with Lib; use Lib; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Ch8; use Sem_Ch8; 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 Snames; use Snames; with Stand; use Stand; with Sinfo; use Sinfo; with Table; with Ttypes; use Ttypes; with Tbuild; use Tbuild; with Urealp; use Urealp; with GNAT.Heap_Sort_A; use GNAT.Heap_Sort_A; package body Sem_Ch13 is SSU : constant Pos := System_Storage_Unit; -- Convenient short hand for commonly used constant ----------------------- -- Local Subprograms -- ----------------------- procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id); -- This routine is called after setting the Esize of type entity Typ. -- The purpose is to deal with the situation where an aligment has been -- inherited from a derived type that is no longer appropriate for the -- new Esize value. In this case, we reset the Alignment to unknown. procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id); -- Given two entities for record components or discriminants, checks -- if they hav overlapping component clauses and issues errors if so. function Get_Alignment_Value (Expr : Node_Id) return Uint; -- Given the expression for an alignment value, returns the corresponding -- Uint value. If the value is inappropriate, then error messages are -- posted as required, and a value of No_Uint is returned. function Is_Operational_Item (N : Node_Id) return Boolean; -- A specification for a stream attribute is allowed before the full -- type is declared, as explained in AI-00137 and the corrigendum. -- Attributes that do not specify a representation characteristic are -- operational attributes. procedure New_Stream_Function (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : Name_Id); -- Create a function renaming of a given stream attribute to the -- designated subprogram and then in the tagged case, provide this as -- a primitive operation, or in the non-tagged case make an appropriate -- TSS entry. Used for Input. This is more properly an expansion activity -- than just semantics, but the presence of user-defined stream functions -- for limited types is a legality check, which is why this takes place -- here rather than in exp_ch13, where it was previously. -- To avoid elaboration anomalies with freeze nodes, for untagged types -- we generate both a subprogram declaration and a subprogram renaming -- declaration, so that the attribute specification is handled as a -- renaming_as_body. For tagged types, the specification is one of the -- primitive specs. procedure New_Stream_Procedure (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : Name_Id; Out_P : Boolean := False); -- Create a procedure renaming of a given stream attribute to the -- designated subprogram and then in the tagged case, provide this as -- a primitive operation, or in the non-tagged case make an appropriate -- TSS entry. Used for Read, Output, Write. procedure Check_Constant_Address_Clause (Expr : Node_Id; U_Ent : Entity_Id); -- Expr is an expression for an address clause. This procedure checks -- that the expression is constant, in the limited sense that it is safe -- to evaluate it at the point the object U_Ent is declared, rather than -- at the point of the address clause. The condition for this to be true -- is that the expression has no variables, no constants declared after -- U_Ent, and no calls to non-pure functions. If this condition is not -- met, then an appropriate error message is posted. procedure Warn_Overlay (Expr : Node_Id; Typ : Entity_Id; Nam : Node_Id); -- Expr is the expression for an address clause for entity Nam whose type -- is Typ. If Typ has a default initialization, check whether the address -- clause might overlay two entities, and emit a warning on the side effect -- that the initialization will cause. ---------------------------------------------- -- Table for Validate_Unchecked_Conversions -- ---------------------------------------------- -- The following table collects unchecked conversions for validation. -- Entries are made by Validate_Unchecked_Conversion and then the -- call to Validate_Unchecked_Conversions does the actual error -- checking and posting of warnings. The reason for this delayed -- processing is to take advantage of back-annotations of size and -- alignment values peformed by the back end. type UC_Entry is record Enode : Node_Id; -- node used for posting warnings Source : Entity_Id; -- source type for unchecked conversion Target : Entity_Id; -- target type for unchecked conversion end record; package Unchecked_Conversions is new Table.Table ( Table_Component_Type => UC_Entry, Table_Index_Type => Int, Table_Low_Bound => 1, Table_Initial => 50, Table_Increment => 200, Table_Name => "Unchecked_Conversions"); -------------------------------------- -- Alignment_Check_For_Esize_Change -- -------------------------------------- procedure Alignment_Check_For_Esize_Change (Typ : Entity_Id) is begin -- If the alignment is known, and not set by a rep clause, and is -- inconsistent with the size being set, then reset it to unknown, -- we assume in this case that the size overrides the inherited -- alignment, and that the alignment must be recomputed. if Known_Alignment (Typ) and then not Has_Alignment_Clause (Typ) and then Esize (Typ) mod (Alignment (Typ) * SSU) /= 0 then Init_Alignment (Typ); end if; end Alignment_Check_For_Esize_Change; ----------------------- -- Analyze_At_Clause -- ----------------------- -- An at clause is replaced by the corresponding Address attribute -- definition clause that is the preferred approach in Ada 95. procedure Analyze_At_Clause (N : Node_Id) is begin Rewrite (N, Make_Attribute_Definition_Clause (Sloc (N), Name => Identifier (N), Chars => Name_Address, Expression => Expression (N))); Analyze_Attribute_Definition_Clause (N); end Analyze_At_Clause; ----------------------------------------- -- Analyze_Attribute_Definition_Clause -- ----------------------------------------- procedure Analyze_Attribute_Definition_Clause (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Nam : constant Node_Id := Name (N); Attr : constant Name_Id := Chars (N); Expr : constant Node_Id := Expression (N); Id : constant Attribute_Id := Get_Attribute_Id (Attr); Ent : Entity_Id; U_Ent : Entity_Id; FOnly : Boolean := False; -- Reset to True for subtype specific attribute (Alignment, Size) -- and for stream attributes, i.e. those cases where in the call -- to Rep_Item_Too_Late, FOnly is set True so that only the freezing -- rules are checked. Note that the case of stream attributes is not -- clear from the RM, but see AI95-00137. Also, the RM seems to -- disallow Storage_Size for derived task types, but that is also -- clearly unintentional. begin Analyze (Nam); Ent := Entity (Nam); if Rep_Item_Too_Early (Ent, N) then return; end if; -- Rep clause applies to full view of incomplete type or private type -- if we have one (if not, this is a premature use of the type). -- However, certain semantic checks need to be done on the specified -- entity (i.e. the private view), so we save it in Ent. if Is_Private_Type (Ent) and then Is_Derived_Type (Ent) and then not Is_Tagged_Type (Ent) and then No (Full_View (Ent)) then -- If this is a private type whose completion is a derivation -- from another private type, there is no full view, and the -- attribute belongs to the type itself, not its underlying parent. U_Ent := Ent; elsif Ekind (Ent) = E_Incomplete_Type then Ent := Underlying_Type (Ent); U_Ent := Ent; else U_Ent := Underlying_Type (Ent); end if; -- Complete other routine error checks if Etype (Nam) = Any_Type then return; elsif Scope (Ent) /= Current_Scope then Error_Msg_N ("entity must be declared in this scope", Nam); return; elsif No (U_Ent) then U_Ent := Ent; elsif Is_Type (U_Ent) and then not Is_First_Subtype (U_Ent) and then Id /= Attribute_Object_Size and then Id /= Attribute_Value_Size and then not From_At_Mod (N) then Error_Msg_N ("cannot specify attribute for subtype", Nam); return; end if; -- Switch on particular attribute case Id is ------------- -- Address -- ------------- -- Address attribute definition clause when Attribute_Address => Address : begin Analyze_And_Resolve (Expr, RTE (RE_Address)); if Present (Address_Clause (U_Ent)) then Error_Msg_N ("address already given for &", Nam); -- Case of address clause for subprogram elsif Is_Subprogram (U_Ent) then if Has_Homonym (U_Ent) then Error_Msg_N ("address clause cannot be given " & "for overloaded subprogram", Nam); end if; -- For subprograms, all address clauses are permitted, -- and we mark the subprogram as having a deferred freeze -- so that Gigi will not elaborate it too soon. -- Above needs more comments, what is too soon about??? Set_Has_Delayed_Freeze (U_Ent); -- Case of address clause for entry elsif Ekind (U_Ent) = E_Entry then if Nkind (Parent (N)) = N_Task_Body then Error_Msg_N ("entry address must be specified in task spec", Nam); end if; -- For entries, we require a constant address Check_Constant_Address_Clause (Expr, U_Ent); if Is_Task_Type (Scope (U_Ent)) and then Comes_From_Source (Scope (U_Ent)) then Error_Msg_N ("?entry address declared for entry in task type", N); Error_Msg_N ("\?only one task can be declared of this type", N); end if; -- Case of address clause for an object elsif Ekind (U_Ent) = E_Variable or else Ekind (U_Ent) = E_Constant then declare Decl : constant Node_Id := Declaration_Node (U_Ent); Expr : constant Node_Id := Expression (N); Typ : constant Entity_Id := Etype (U_Ent); begin -- Exported variables cannot have an address clause, -- because this cancels the effect of the pragma Export if Is_Exported (U_Ent) then Error_Msg_N ("cannot export object with address clause", Nam); -- Imported variables can have an address clause, but then -- the import is pretty meaningless except to suppress -- initializations, so we do not need such variables to -- be statically allocated (and in fact it causes trouble -- if the address clause is a local value). elsif Is_Imported (U_Ent) then Set_Is_Statically_Allocated (U_Ent, False); end if; -- We mark a possible modification of a variable with an -- address clause, since it is likely aliasing is occurring. Note_Possible_Modification (Nam); -- If we have no initialization of any kind, then we can -- safely defer the elaboration of the variable to its -- freezing point, so that the address clause will be -- computed at the proper point. -- The same processing applies to all initialized scalar -- types and all access types. Packed bit arrays of size -- up to 64 are represented using a modular type with an -- initialization (to zero) and can be processed like -- other initialized scalar types. if (No (Expression (Decl)) and then not Has_Non_Null_Base_Init_Proc (Typ)) or else (Present (Expression (Decl)) and then Is_Scalar_Type (Typ)) or else Is_Access_Type (Typ) or else (Is_Bit_Packed_Array (Base_Type (Typ)) and then Is_Modular_Integer_Type (Packed_Array_Type (Typ))) then Set_Has_Delayed_Freeze (U_Ent); -- Otherwise, we require the address clause to be constant else Check_Constant_Address_Clause (Expr, U_Ent); end if; if Is_Exported (U_Ent) then Error_Msg_N ("& cannot be exported if an address clause is given", Nam); Error_Msg_N ("\define and export a variable " & "that holds its address instead", Nam); end if; if not Error_Posted (Expr) then Warn_Overlay (Expr, Typ, Nam); end if; -- If entity has delayed freeze then we will generate -- an alignment check at the freeze point. If there is -- no delayed freeze we can do it right now. if not Has_Delayed_Freeze (U_Ent) then Apply_Alignment_Check (U_Ent, N); end if; -- Kill the size check code, since we are not allocating -- the variable, it is somewhere else. Kill_Size_Check_Code (U_Ent); end; -- Not a valid entity for an address clause else Error_Msg_N ("address cannot be given for &", Nam); end if; end Address; --------------- -- Alignment -- --------------- -- Alignment attribute definition clause when Attribute_Alignment => Alignment_Block : declare Align : Uint := Get_Alignment_Value (Expr); begin FOnly := True; if not Is_Type (U_Ent) and then Ekind (U_Ent) /= E_Variable and then Ekind (U_Ent) /= E_Constant then Error_Msg_N ("alignment cannot be given for &", Nam); elsif Has_Alignment_Clause (U_Ent) then Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent)); Error_Msg_N ("alignment clause previously given#", N); elsif Align /= No_Uint then Set_Has_Alignment_Clause (U_Ent); Set_Alignment (U_Ent, Align); end if; end Alignment_Block; --------------- -- Bit_Order -- --------------- -- Bit_Order attribute definition clause when Attribute_Bit_Order => Bit_Order : declare begin if not Is_Record_Type (U_Ent) then Error_Msg_N ("Bit_Order can only be defined for record type", Nam); else Analyze_And_Resolve (Expr, RTE (RE_Bit_Order)); if Etype (Expr) = Any_Type then return; elsif not Is_Static_Expression (Expr) then Error_Msg_N ("Bit_Order requires static expression", Expr); else if (Expr_Value (Expr) = 0) /= Bytes_Big_Endian then Set_Reverse_Bit_Order (U_Ent, True); end if; end if; end if; end Bit_Order; -------------------- -- Component_Size -- -------------------- -- Component_Size attribute definition clause when Attribute_Component_Size => Component_Size_Case : declare Csize : constant Uint := Static_Integer (Expr); Btype : Entity_Id; Biased : Boolean; New_Ctyp : Entity_Id; Decl : Node_Id; begin if not Is_Array_Type (U_Ent) then Error_Msg_N ("component size requires array type", Nam); return; end if; Btype := Base_Type (U_Ent); if Has_Component_Size_Clause (Btype) then Error_Msg_N ("component size clase for& previously given", Nam); elsif Csize /= No_Uint then Check_Size (Expr, Component_Type (Btype), Csize, Biased); if Has_Aliased_Components (Btype) and then Csize < 32 and then Csize /= 8 and then Csize /= 16 then Error_Msg_N ("component size incorrect for aliased components", N); return; end if; -- For the biased case, build a declaration for a subtype -- that will be used to represent the biased subtype that -- reflects the biased representation of components. We need -- this subtype to get proper conversions on referencing -- elements of the array. if Biased then New_Ctyp := Make_Defining_Identifier (Loc, Chars => New_External_Name (Chars (U_Ent), 'C', 0, 'T')); Decl := Make_Subtype_Declaration (Loc, Defining_Identifier => New_Ctyp, Subtype_Indication => New_Occurrence_Of (Component_Type (Btype), Loc)); Set_Parent (Decl, N); Analyze (Decl, Suppress => All_Checks); Set_Has_Delayed_Freeze (New_Ctyp, False); Set_Esize (New_Ctyp, Csize); Set_RM_Size (New_Ctyp, Csize); Init_Alignment (New_Ctyp); Set_Has_Biased_Representation (New_Ctyp, True); Set_Is_Itype (New_Ctyp, True); Set_Associated_Node_For_Itype (New_Ctyp, U_Ent); Set_Component_Type (Btype, New_Ctyp); end if; Set_Component_Size (Btype, Csize); Set_Has_Component_Size_Clause (Btype, True); Set_Has_Non_Standard_Rep (Btype, True); end if; end Component_Size_Case; ------------------ -- External_Tag -- ------------------ when Attribute_External_Tag => External_Tag : begin if not Is_Tagged_Type (U_Ent) then Error_Msg_N ("should be a tagged type", Nam); end if; Analyze_And_Resolve (Expr, Standard_String); if not Is_Static_Expression (Expr) then Error_Msg_N ("must be a static string", Nam); end if; Set_Has_External_Tag_Rep_Clause (U_Ent); end External_Tag; ----------- -- Input -- ----------- when Attribute_Input => Input : declare Subp : Entity_Id := Empty; I : Interp_Index; It : Interp; Pnam : Entity_Id; function Has_Good_Profile (Subp : Entity_Id) return Boolean; -- Return true if the entity is a function with an appropriate -- profile for the Input attribute. function Has_Good_Profile (Subp : Entity_Id) return Boolean is F : Entity_Id; Ok : Boolean := False; begin if Ekind (Subp) = E_Function then F := First_Formal (Subp); if Present (F) and then No (Next_Formal (F)) then if Ekind (Etype (F)) = E_Anonymous_Access_Type and then Designated_Type (Etype (F)) = Class_Wide_Type (RTE (RE_Root_Stream_Type)) then Ok := Base_Type (Etype (Subp)) = Base_Type (Ent); end if; end if; end if; return Ok; end Has_Good_Profile; -- Start of processing for Input attribute definition begin FOnly := True; if not Is_Type (U_Ent) then Error_Msg_N ("local name must be a subtype", Nam); return; else Pnam := TSS (Base_Type (U_Ent), Name_uInput); if Present (Pnam) and then Base_Type (Etype (Pnam)) = Base_Type (U_Ent) then Error_Msg_Sloc := Sloc (Pnam); Error_Msg_N ("input attribute already defined #", Nam); return; end if; end if; Analyze (Expr); if Is_Entity_Name (Expr) then if not Is_Overloaded (Expr) then if Has_Good_Profile (Entity (Expr)) then Subp := Entity (Expr); end if; else Get_First_Interp (Expr, I, It); while Present (It.Nam) loop if Has_Good_Profile (It.Nam) then Subp := It.Nam; exit; end if; Get_Next_Interp (I, It); end loop; end if; end if; if Present (Subp) then Set_Entity (Expr, Subp); Set_Etype (Expr, Etype (Subp)); New_Stream_Function (N, U_Ent, Subp, Name_uInput); else Error_Msg_N ("incorrect expression for input attribute", Expr); return; end if; end Input; ------------------- -- Machine_Radix -- ------------------- -- Machine radix attribute definition clause when Attribute_Machine_Radix => Machine_Radix : declare Radix : constant Uint := Static_Integer (Expr); begin if not Is_Decimal_Fixed_Point_Type (U_Ent) then Error_Msg_N ("decimal fixed-point type expected for &", Nam); elsif Has_Machine_Radix_Clause (U_Ent) then Error_Msg_Sloc := Sloc (Alignment_Clause (U_Ent)); Error_Msg_N ("machine radix clause previously given#", N); elsif Radix /= No_Uint then Set_Has_Machine_Radix_Clause (U_Ent); Set_Has_Non_Standard_Rep (Base_Type (U_Ent)); if Radix = 2 then null; elsif Radix = 10 then Set_Machine_Radix_10 (U_Ent); else Error_Msg_N ("machine radix value must be 2 or 10", Expr); end if; end if; end Machine_Radix; ----------------- -- Object_Size -- ----------------- -- Object_Size attribute definition clause when Attribute_Object_Size => Object_Size : declare Size : constant Uint := Static_Integer (Expr); Biased : Boolean; begin if not Is_Type (U_Ent) then Error_Msg_N ("Object_Size cannot be given for &", Nam); elsif Has_Object_Size_Clause (U_Ent) then Error_Msg_N ("Object_Size already given for &", Nam); else Check_Size (Expr, U_Ent, Size, Biased); if Size /= 8 and then Size /= 16 and then Size /= 32 and then UI_Mod (Size, 64) /= 0 then Error_Msg_N ("Object_Size must be 8, 16, 32, or multiple of 64", Expr); end if; Set_Esize (U_Ent, Size); Set_Has_Object_Size_Clause (U_Ent); Alignment_Check_For_Esize_Change (U_Ent); end if; end Object_Size; ------------ -- Output -- ------------ when Attribute_Output => Output : declare Subp : Entity_Id := Empty; I : Interp_Index; It : Interp; Pnam : Entity_Id; function Has_Good_Profile (Subp : Entity_Id) return Boolean; -- Return true if the entity is a procedure with an -- appropriate profile for the output attribute. function Has_Good_Profile (Subp : Entity_Id) return Boolean is F : Entity_Id; Ok : Boolean := False; begin if Ekind (Subp) = E_Procedure then F := First_Formal (Subp); if Present (F) then if Ekind (Etype (F)) = E_Anonymous_Access_Type and then Designated_Type (Etype (F)) = Class_Wide_Type (RTE (RE_Root_Stream_Type)) then Next_Formal (F); Ok := Present (F) and then Parameter_Mode (F) = E_In_Parameter and then Base_Type (Etype (F)) = Base_Type (Ent) and then No (Next_Formal (F)); end if; end if; end if; return Ok; end Has_Good_Profile; begin FOnly := True; if not Is_Type (U_Ent) then Error_Msg_N ("local name must be a subtype", Nam); return; else Pnam := TSS (Base_Type (U_Ent), Name_uOutput); if Present (Pnam) and then Base_Type (Etype (Next_Formal (First_Formal (Pnam)))) = Base_Type (U_Ent) then Error_Msg_Sloc := Sloc (Pnam); Error_Msg_N ("output attribute already defined #", Nam); return; end if; end if; Analyze (Expr); if Is_Entity_Name (Expr) then if not Is_Overloaded (Expr) then if Has_Good_Profile (Entity (Expr)) then Subp := Entity (Expr); end if; else Get_First_Interp (Expr, I, It); while Present (It.Nam) loop if Has_Good_Profile (It.Nam) then Subp := It.Nam; exit; end if; Get_Next_Interp (I, It); end loop; end if; end if; if Present (Subp) then Set_Entity (Expr, Subp); Set_Etype (Expr, Etype (Subp)); New_Stream_Procedure (N, U_Ent, Subp, Name_uOutput); else Error_Msg_N ("incorrect expression for output attribute", Expr); return; end if; end Output; ---------- -- Read -- ---------- when Attribute_Read => Read : declare Subp : Entity_Id := Empty; I : Interp_Index; It : Interp; Pnam : Entity_Id; function Has_Good_Profile (Subp : Entity_Id) return Boolean; -- Return true if the entity is a procedure with an appropriate -- profile for the Read attribute. function Has_Good_Profile (Subp : Entity_Id) return Boolean is F : Entity_Id; Ok : Boolean := False; begin if Ekind (Subp) = E_Procedure then F := First_Formal (Subp); if Present (F) then if Ekind (Etype (F)) = E_Anonymous_Access_Type and then Designated_Type (Etype (F)) = Class_Wide_Type (RTE (RE_Root_Stream_Type)) then Next_Formal (F); Ok := Present (F) and then Parameter_Mode (F) = E_Out_Parameter and then Base_Type (Etype (F)) = Base_Type (Ent) and then No (Next_Formal (F)); end if; end if; end if; return Ok; end Has_Good_Profile; -- Start of processing for Read attribute definition begin FOnly := True; if not Is_Type (U_Ent) then Error_Msg_N ("local name must be a subtype", Nam); return; else Pnam := TSS (Base_Type (U_Ent), Name_uRead); if Present (Pnam) and then Base_Type (Etype (Next_Formal (First_Formal (Pnam)))) = Base_Type (U_Ent) then Error_Msg_Sloc := Sloc (Pnam); Error_Msg_N ("read attribute already defined #", Nam); return; end if; end if; Analyze (Expr); if Is_Entity_Name (Expr) then if not Is_Overloaded (Expr) then if Has_Good_Profile (Entity (Expr)) then Subp := Entity (Expr); end if; else Get_First_Interp (Expr, I, It); while Present (It.Nam) loop if Has_Good_Profile (It.Nam) then Subp := It.Nam; exit; end if; Get_Next_Interp (I, It); end loop; end if; end if; if Present (Subp) then Set_Entity (Expr, Subp); Set_Etype (Expr, Etype (Subp)); New_Stream_Procedure (N, U_Ent, Subp, Name_uRead, True); else Error_Msg_N ("incorrect expression for read attribute", Expr); return; end if; end Read; ---------- -- Size -- ---------- -- Size attribute definition clause when Attribute_Size => Size : declare Size : constant Uint := Static_Integer (Expr); Etyp : Entity_Id; Biased : Boolean; begin FOnly := True; if Has_Size_Clause (U_Ent) then Error_Msg_N ("size already given for &", Nam); elsif not Is_Type (U_Ent) and then Ekind (U_Ent) /= E_Variable and then Ekind (U_Ent) /= E_Constant then Error_Msg_N ("size cannot be given for &", Nam); elsif Is_Array_Type (U_Ent) and then not Is_Constrained (U_Ent) then Error_Msg_N ("size cannot be given for unconstrained array", Nam); elsif Size /= No_Uint then if Is_Type (U_Ent) then Etyp := U_Ent; else Etyp := Etype (U_Ent); end if; -- Check size, note that Gigi is in charge of checking -- that the size of an array or record type is OK. Also -- we do not check the size in the ordinary fixed-point -- case, since it is too early to do so (there may be a -- subsequent small clause that affects the size). We can -- check the size if a small clause has already been given. if not Is_Ordinary_Fixed_Point_Type (U_Ent) or else Has_Small_Clause (U_Ent) then Check_Size (Expr, Etyp, Size, Biased); Set_Has_Biased_Representation (U_Ent, Biased); end if; -- For types set RM_Size and Esize if possible if Is_Type (U_Ent) then Set_RM_Size (U_Ent, Size); -- For scalar types, increase Object_Size to power of 2, -- but not less than a storage unit in any case (i.e., -- normally this means it will be byte addressable). if Is_Scalar_Type (U_Ent) then if Size <= System_Storage_Unit then Init_Esize (U_Ent, System_Storage_Unit); elsif Size <= 16 then Init_Esize (U_Ent, 16); elsif Size <= 32 then Init_Esize (U_Ent, 32); else Set_Esize (U_Ent, (Size + 63) / 64 * 64); end if; -- For all other types, object size = value size. The -- backend will adjust as needed. else Set_Esize (U_Ent, Size); end if; Alignment_Check_For_Esize_Change (U_Ent); -- For objects, set Esize only else Set_Esize (U_Ent, Size); end if; Set_Has_Size_Clause (U_Ent); end if; end Size; ----------- -- Small -- ----------- -- Small attribute definition clause when Attribute_Small => Small : declare Implicit_Base : constant Entity_Id := Base_Type (U_Ent); Small : Ureal; begin Analyze_And_Resolve (Expr, Any_Real); if Etype (Expr) = Any_Type then return; elsif not Is_Static_Expression (Expr) then Error_Msg_N ("small requires static expression", Expr); return; else Small := Expr_Value_R (Expr); if Small <= Ureal_0 then Error_Msg_N ("small value must be greater than zero", Expr); return; end if; end if; if not Is_Ordinary_Fixed_Point_Type (U_Ent) then Error_Msg_N ("small requires an ordinary fixed point type", Nam); elsif Has_Small_Clause (U_Ent) then Error_Msg_N ("small already given for &", Nam); elsif Small > Delta_Value (U_Ent) then Error_Msg_N ("small value must not be greater then delta value", Nam); else Set_Small_Value (U_Ent, Small); Set_Small_Value (Implicit_Base, Small); Set_Has_Small_Clause (U_Ent); Set_Has_Small_Clause (Implicit_Base); Set_Has_Non_Standard_Rep (Implicit_Base); end if; end Small; ------------------ -- Storage_Size -- ------------------ -- Storage_Size attribute definition clause when Attribute_Storage_Size => Storage_Size : declare Btype : constant Entity_Id := Base_Type (U_Ent); Sprag : Node_Id; begin if Is_Task_Type (U_Ent) then FOnly := True; end if; if not Is_Access_Type (U_Ent) and then Ekind (U_Ent) /= E_Task_Type then Error_Msg_N ("storage size cannot be given for &", Nam); elsif Is_Access_Type (U_Ent) and Is_Derived_Type (U_Ent) then Error_Msg_N ("storage size cannot be given for a derived access type", Nam); elsif Has_Storage_Size_Clause (Btype) then Error_Msg_N ("storage size already given for &", Nam); else Analyze_And_Resolve (Expr, Any_Integer); if Is_Access_Type (U_Ent) then if Present (Associated_Storage_Pool (U_Ent)) then Error_Msg_N ("storage pool already given for &", Nam); return; end if; if Compile_Time_Known_Value (Expr) and then Expr_Value (Expr) = 0 then Set_No_Pool_Assigned (Btype); end if; else -- Is_Task_Type (U_Ent) Sprag := Get_Rep_Pragma (Btype, Name_Storage_Size); if Present (Sprag) then Error_Msg_Sloc := Sloc (Sprag); Error_Msg_N ("Storage_Size already specified#", Nam); return; end if; end if; Set_Has_Storage_Size_Clause (Btype); end if; end Storage_Size; ------------------ -- Storage_Pool -- ------------------ -- Storage_Pool attribute definition clause when Attribute_Storage_Pool => Storage_Pool : declare Pool : Entity_Id; begin if Ekind (U_Ent) /= E_Access_Type and then Ekind (U_Ent) /= E_General_Access_Type then Error_Msg_N ( "storage pool can only be given for access types", Nam); return; elsif Is_Derived_Type (U_Ent) then Error_Msg_N ("storage pool cannot be given for a derived access type", Nam); elsif Has_Storage_Size_Clause (U_Ent) then Error_Msg_N ("storage size already given for &", Nam); return; elsif Present (Associated_Storage_Pool (U_Ent)) then Error_Msg_N ("storage pool already given for &", Nam); return; end if; Analyze_And_Resolve (Expr, Class_Wide_Type (RTE (RE_Root_Storage_Pool))); -- If the argument is a name that is not an entity name, then -- we construct a renaming operation to define an entity of -- type storage pool. if not Is_Entity_Name (Expr) and then Is_Object_Reference (Expr) then Pool := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('P')); declare Rnode : constant Node_Id := Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Pool, Subtype_Mark => New_Occurrence_Of (Etype (Expr), Loc), Name => Expr); begin Insert_Before (N, Rnode); Analyze (Rnode); Set_Associated_Storage_Pool (U_Ent, Pool); end; elsif Is_Entity_Name (Expr) then Pool := Entity (Expr); -- If pool is a renamed object, get original one. This can -- happen with an explicit renaming, and within instances. while Present (Renamed_Object (Pool)) and then Is_Entity_Name (Renamed_Object (Pool)) loop Pool := Entity (Renamed_Object (Pool)); end loop; if Present (Renamed_Object (Pool)) and then Nkind (Renamed_Object (Pool)) = N_Type_Conversion and then Is_Entity_Name (Expression (Renamed_Object (Pool))) then Pool := Entity (Expression (Renamed_Object (Pool))); end if; if Present (Etype (Pool)) and then Etype (Pool) /= RTE (RE_Stack_Bounded_Pool) and then Etype (Pool) /= RTE (RE_Unbounded_Reclaim_Pool) then Set_Associated_Storage_Pool (U_Ent, Pool); else Error_Msg_N ("Non sharable GNAT Pool", Expr); end if; -- The pool may be specified as the Storage_Pool of some other -- type. It is rewritten as a class_wide conversion of the -- corresponding pool entity. elsif Nkind (Expr) = N_Type_Conversion and then Is_Entity_Name (Expression (Expr)) and then Nkind (Original_Node (Expr)) = N_Attribute_Reference then Pool := Entity (Expression (Expr)); if Present (Etype (Pool)) and then Etype (Pool) /= RTE (RE_Stack_Bounded_Pool) and then Etype (Pool) /= RTE (RE_Unbounded_Reclaim_Pool) then Set_Associated_Storage_Pool (U_Ent, Pool); else Error_Msg_N ("Non sharable GNAT Pool", Expr); end if; else Error_Msg_N ("incorrect reference to a Storage Pool", Expr); return; end if; end Storage_Pool; ---------------- -- Value_Size -- ---------------- -- Value_Size attribute definition clause when Attribute_Value_Size => Value_Size : declare Size : constant Uint := Static_Integer (Expr); Biased : Boolean; begin if not Is_Type (U_Ent) then Error_Msg_N ("Value_Size cannot be given for &", Nam); elsif Present (Get_Attribute_Definition_Clause (U_Ent, Attribute_Value_Size)) then Error_Msg_N ("Value_Size already given for &", Nam); else if Is_Elementary_Type (U_Ent) then Check_Size (Expr, U_Ent, Size, Biased); Set_Has_Biased_Representation (U_Ent, Biased); end if; Set_RM_Size (U_Ent, Size); end if; end Value_Size; ----------- -- Write -- ----------- -- Write attribute definition clause -- check for class-wide case will be performed later when Attribute_Write => Write : declare Subp : Entity_Id := Empty; I : Interp_Index; It : Interp; Pnam : Entity_Id; function Has_Good_Profile (Subp : Entity_Id) return Boolean; -- Return true if the entity is a procedure with an -- appropriate profile for the write attribute. function Has_Good_Profile (Subp : Entity_Id) return Boolean is F : Entity_Id; Ok : Boolean := False; begin if Ekind (Subp) = E_Procedure then F := First_Formal (Subp); if Present (F) then if Ekind (Etype (F)) = E_Anonymous_Access_Type and then Designated_Type (Etype (F)) = Class_Wide_Type (RTE (RE_Root_Stream_Type)) then Next_Formal (F); Ok := Present (F) and then Parameter_Mode (F) = E_In_Parameter and then Base_Type (Etype (F)) = Base_Type (Ent) and then No (Next_Formal (F)); end if; end if; end if; return Ok; end Has_Good_Profile; -- Start of processing for Write attribute definition begin FOnly := True; if not Is_Type (U_Ent) then Error_Msg_N ("local name must be a subtype", Nam); return; end if; Pnam := TSS (Base_Type (U_Ent), Name_uWrite); if Present (Pnam) and then Base_Type (Etype (Next_Formal (First_Formal (Pnam)))) = Base_Type (U_Ent) then Error_Msg_Sloc := Sloc (Pnam); Error_Msg_N ("write attribute already defined #", Nam); return; end if; Analyze (Expr); if Is_Entity_Name (Expr) then if not Is_Overloaded (Expr) then if Has_Good_Profile (Entity (Expr)) then Subp := Entity (Expr); end if; else Get_First_Interp (Expr, I, It); while Present (It.Nam) loop if Has_Good_Profile (It.Nam) then Subp := It.Nam; exit; end if; Get_Next_Interp (I, It); end loop; end if; end if; if Present (Subp) then Set_Entity (Expr, Subp); Set_Etype (Expr, Etype (Subp)); New_Stream_Procedure (N, U_Ent, Subp, Name_uWrite); else Error_Msg_N ("incorrect expression for write attribute", Expr); return; end if; end Write; -- All other attributes cannot be set when others => Error_Msg_N ("attribute& cannot be set with definition clause", N); end case; -- The test for the type being frozen must be performed after -- any expression the clause has been analyzed since the expression -- itself might cause freezing that makes the clause illegal. if Rep_Item_Too_Late (U_Ent, N, FOnly) then return; end if; end Analyze_Attribute_Definition_Clause; ---------------------------- -- Analyze_Code_Statement -- ---------------------------- procedure Analyze_Code_Statement (N : Node_Id) is HSS : constant Node_Id := Parent (N); SBody : constant Node_Id := Parent (HSS); Subp : constant Entity_Id := Current_Scope; Stmt : Node_Id; Decl : Node_Id; StmtO : Node_Id; DeclO : Node_Id; begin -- Analyze and check we get right type, note that this implements the -- requirement (RM 13.8(1)) that Machine_Code be with'ed, since that -- is the only way that Asm_Insn could possibly be visible. Analyze_And_Resolve (Expression (N)); if Etype (Expression (N)) = Any_Type then return; elsif Etype (Expression (N)) /= RTE (RE_Asm_Insn) then Error_Msg_N ("incorrect type for code statement", N); return; end if; -- Make sure we appear in the handled statement sequence of a -- subprogram (RM 13.8(3)). if Nkind (HSS) /= N_Handled_Sequence_Of_Statements or else Nkind (SBody) /= N_Subprogram_Body then Error_Msg_N ("code statement can only appear in body of subprogram", N); return; end if; -- Do remaining checks (RM 13.8(3)) if not already done if not Is_Machine_Code_Subprogram (Subp) then Set_Is_Machine_Code_Subprogram (Subp); -- No exception handlers allowed if Present (Exception_Handlers (HSS)) then Error_Msg_N ("exception handlers not permitted in machine code subprogram", First (Exception_Handlers (HSS))); end if; -- No declarations other than use clauses and pragmas (we allow -- certain internally generated declarations as well). Decl := First (Declarations (SBody)); while Present (Decl) loop DeclO := Original_Node (Decl); if Comes_From_Source (DeclO) and then Nkind (DeclO) /= N_Pragma and then Nkind (DeclO) /= N_Use_Package_Clause and then Nkind (DeclO) /= N_Use_Type_Clause and then Nkind (DeclO) /= N_Implicit_Label_Declaration then Error_Msg_N ("this declaration not allowed in machine code subprogram", DeclO); end if; Next (Decl); end loop; -- No statements other than code statements, pragmas, and labels. -- Again we allow certain internally generated statements. Stmt := First (Statements (HSS)); while Present (Stmt) loop StmtO := Original_Node (Stmt); if Comes_From_Source (StmtO) and then Nkind (StmtO) /= N_Pragma and then Nkind (StmtO) /= N_Label and then Nkind (StmtO) /= N_Code_Statement then Error_Msg_N ("this statement is not allowed in machine code subprogram", StmtO); end if; Next (Stmt); end loop; end if; end Analyze_Code_Statement; ----------------------------------------------- -- Analyze_Enumeration_Representation_Clause -- ----------------------------------------------- procedure Analyze_Enumeration_Representation_Clause (N : Node_Id) is Ident : constant Node_Id := Identifier (N); Aggr : constant Node_Id := Array_Aggregate (N); Enumtype : Entity_Id; Elit : Entity_Id; Expr : Node_Id; Assoc : Node_Id; Choice : Node_Id; Val : Uint; Err : Boolean := False; Lo : constant Uint := Expr_Value (Type_Low_Bound (Universal_Integer)); Hi : constant Uint := Expr_Value (Type_High_Bound (Universal_Integer)); Min : Uint; Max : Uint; begin -- First some basic error checks Find_Type (Ident); Enumtype := Entity (Ident); if Enumtype = Any_Type or else Rep_Item_Too_Early (Enumtype, N) then return; else Enumtype := Underlying_Type (Enumtype); end if; if not Is_Enumeration_Type (Enumtype) then Error_Msg_NE ("enumeration type required, found}", Ident, First_Subtype (Enumtype)); return; end if; if Scope (Enumtype) /= Current_Scope then Error_Msg_N ("type must be declared in this scope", Ident); return; elsif not Is_First_Subtype (Enumtype) then Error_Msg_N ("cannot give enumeration rep clause for subtype", N); return; elsif Has_Enumeration_Rep_Clause (Enumtype) then Error_Msg_N ("duplicate enumeration rep clause ignored", N); return; elsif Root_Type (Enumtype) = Standard_Character or else Root_Type (Enumtype) = Standard_Wide_Character then Error_Msg_N ("enumeration rep clause not allowed for this type", N); else Set_Has_Enumeration_Rep_Clause (Enumtype); Set_Has_Enumeration_Rep_Clause (Base_Type (Enumtype)); end if; -- Now we process the aggregate. Note that we don't use the normal -- aggregate code for this purpose, because we don't want any of the -- normal expansion activities, and a number of special semantic -- rules apply (including the component type being any integer type) -- Badent signals that we found some incorrect entries processing -- the list. The final checks for completeness and ordering are -- skipped in this case. Elit := First_Literal (Enumtype); -- First the positional entries if any if Present (Expressions (Aggr)) then Expr := First (Expressions (Aggr)); while Present (Expr) loop if No (Elit) then Error_Msg_N ("too many entries in aggregate", Expr); return; end if; Val := Static_Integer (Expr); if Val = No_Uint then Err := True; elsif Val < Lo or else Hi < Val then Error_Msg_N ("value outside permitted range", Expr); Err := True; end if; Set_Enumeration_Rep (Elit, Val); Set_Enumeration_Rep_Expr (Elit, Expr); Next (Expr); Next (Elit); end loop; end if; -- Now process the named entries if present if Present (Component_Associations (Aggr)) then Assoc := First (Component_Associations (Aggr)); while Present (Assoc) loop Choice := First (Choices (Assoc)); if Present (Next (Choice)) then Error_Msg_N ("multiple choice not allowed here", Next (Choice)); Err := True; end if; if Nkind (Choice) = N_Others_Choice then Error_Msg_N ("others choice not allowed here", Choice); Err := True; elsif Nkind (Choice) = N_Range then -- ??? should allow zero/one element range here Error_Msg_N ("range not allowed here", Choice); Err := True; else Analyze_And_Resolve (Choice, Enumtype); if Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)) then Error_Msg_N ("subtype name not allowed here", Choice); Err := True; -- ??? should allow static subtype with zero/one entry elsif Etype (Choice) = Base_Type (Enumtype) then if not Is_Static_Expression (Choice) then Error_Msg_N ("non-static expression used for choice", Choice); Err := True; else Elit := Expr_Value_E (Choice); if Present (Enumeration_Rep_Expr (Elit)) then Error_Msg_Sloc := Sloc (Enumeration_Rep_Expr (Elit)); Error_Msg_NE ("representation for& previously given#", Choice, Elit); Err := True; end if; Set_Enumeration_Rep_Expr (Elit, Choice); Expr := Expression (Assoc); Val := Static_Integer (Expr); if Val = No_Uint then Err := True; elsif Val < Lo or else Hi < Val then Error_Msg_N ("value outside permitted range", Expr); Err := True; end if; Set_Enumeration_Rep (Elit, Val); end if; end if; end if; Next (Assoc); end loop; end if; -- Aggregate is fully processed. Now we check that a full set of -- representations was given, and that they are in range and in order. -- These checks are only done if no other errors occurred. if not Err then Min := No_Uint; Max := No_Uint; Elit := First_Literal (Enumtype); while Present (Elit) loop if No (Enumeration_Rep_Expr (Elit)) then Error_Msg_NE ("missing representation for&!", N, Elit); else Val := Enumeration_Rep (Elit); if Min = No_Uint then Min := Val; end if; if Val /= No_Uint then if Max /= No_Uint and then Val <= Max then Error_Msg_NE ("enumeration value for& not ordered!", Enumeration_Rep_Expr (Elit), Elit); end if; Max := Val; end if; -- If there is at least one literal whose representation -- is not equal to the Pos value, then note that this -- enumeration type has a non-standard representation. if Val /= Enumeration_Pos (Elit) then Set_Has_Non_Standard_Rep (Base_Type (Enumtype)); end if; end if; Next (Elit); end loop; -- Now set proper size information declare Minsize : Uint := UI_From_Int (Minimum_Size (Enumtype)); begin if Has_Size_Clause (Enumtype) then if Esize (Enumtype) >= Minsize then null; else Minsize := UI_From_Int (Minimum_Size (Enumtype, Biased => True)); if Esize (Enumtype) < Minsize then Error_Msg_N ("previously given size is too small", N); else Set_Has_Biased_Representation (Enumtype); end if; end if; else Set_RM_Size (Enumtype, Minsize); Set_Enum_Esize (Enumtype); end if; Set_RM_Size (Base_Type (Enumtype), RM_Size (Enumtype)); Set_Esize (Base_Type (Enumtype), Esize (Enumtype)); Set_Alignment (Base_Type (Enumtype), Alignment (Enumtype)); end; end if; -- We repeat the too late test in case it froze itself! if Rep_Item_Too_Late (Enumtype, N) then null; end if; end Analyze_Enumeration_Representation_Clause; ---------------------------- -- Analyze_Free_Statement -- ---------------------------- procedure Analyze_Free_Statement (N : Node_Id) is begin Analyze (Expression (N)); end Analyze_Free_Statement; ------------------------------------------ -- Analyze_Record_Representation_Clause -- ------------------------------------------ procedure Analyze_Record_Representation_Clause (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Ident : constant Node_Id := Identifier (N); Rectype : Entity_Id; Fent : Entity_Id; CC : Node_Id; Posit : Uint; Fbit : Uint; Lbit : Uint; Hbit : Uint := Uint_0; Comp : Entity_Id; Ocomp : Entity_Id; Biased : Boolean; Max_Bit_So_Far : Uint; -- Records the maximum bit position so far. If all field positoins -- are monotonically increasing, then we can skip the circuit for -- checking for overlap, since no overlap is possible. Overlap_Check_Required : Boolean; -- Used to keep track of whether or not an overlap check is required Ccount : Natural := 0; -- Number of component clauses in record rep clause begin Find_Type (Ident); Rectype := Entity (Ident); if Rectype = Any_Type or else Rep_Item_Too_Early (Rectype, N) then return; else Rectype := Underlying_Type (Rectype); end if; -- First some basic error checks if not Is_Record_Type (Rectype) then Error_Msg_NE ("record type required, found}", Ident, First_Subtype (Rectype)); return; elsif Is_Unchecked_Union (Rectype) then Error_Msg_N ("record rep clause not allowed for Unchecked_Union", N); elsif Scope (Rectype) /= Current_Scope then Error_Msg_N ("type must be declared in this scope", N); return; elsif not Is_First_Subtype (Rectype) then Error_Msg_N ("cannot give record rep clause for subtype", N); return; elsif Has_Record_Rep_Clause (Rectype) then Error_Msg_N ("duplicate record rep clause ignored", N); return; elsif Rep_Item_Too_Late (Rectype, N) then return; end if; if Present (Mod_Clause (N)) then declare Loc : constant Source_Ptr := Sloc (N); M : constant Node_Id := Mod_Clause (N); P : constant List_Id := Pragmas_Before (M); Mod_Val : Uint; AtM_Nod : Node_Id; begin if Present (P) then Analyze_List (P); end if; -- In Tree_Output mode, expansion is disabled, but we must -- convert the Mod clause into an alignment clause anyway, so -- that the back-end can compute and back-annotate properly the -- size and alignment of types that may include this record. if Operating_Mode = Check_Semantics and then Tree_Output then AtM_Nod := Make_Attribute_Definition_Clause (Loc, Name => New_Reference_To (Base_Type (Rectype), Loc), Chars => Name_Alignment, Expression => Relocate_Node (Expression (M))); Set_From_At_Mod (AtM_Nod); Insert_After (N, AtM_Nod); Mod_Val := Get_Alignment_Value (Expression (AtM_Nod)); Set_Mod_Clause (N, Empty); else -- Get the alignment value to perform error checking Mod_Val := Get_Alignment_Value (Expression (M)); end if; end; end if; -- Clear any existing component clauses for the type (this happens -- with derived types, where we are now overriding the original) Fent := First_Entity (Rectype); Comp := Fent; while Present (Comp) loop if Ekind (Comp) = E_Component or else Ekind (Comp) = E_Discriminant then Set_Component_Clause (Comp, Empty); end if; Next_Entity (Comp); end loop; -- All done if no component clauses CC := First (Component_Clauses (N)); if No (CC) then return; end if; -- If a tag is present, then create a component clause that places -- it at the start of the record (otherwise gigi may place it after -- other fields that have rep clauses). if Nkind (Fent) = N_Defining_Identifier and then Chars (Fent) = Name_uTag then Set_Component_Bit_Offset (Fent, Uint_0); Set_Normalized_Position (Fent, Uint_0); Set_Normalized_First_Bit (Fent, Uint_0); Set_Normalized_Position_Max (Fent, Uint_0); Init_Esize (Fent, System_Address_Size); Set_Component_Clause (Fent, Make_Component_Clause (Loc, Component_Name => Make_Identifier (Loc, Chars => Name_uTag), Position => Make_Integer_Literal (Loc, Intval => Uint_0), First_Bit => Make_Integer_Literal (Loc, Intval => Uint_0), Last_Bit => Make_Integer_Literal (Loc, UI_From_Int (System_Address_Size)))); Ccount := Ccount + 1; end if; -- A representation like this applies to the base type Set_Has_Record_Rep_Clause (Base_Type (Rectype)); Set_Has_Non_Standard_Rep (Base_Type (Rectype)); Set_Has_Specified_Layout (Base_Type (Rectype)); Max_Bit_So_Far := Uint_Minus_1; Overlap_Check_Required := False; -- Process the component clauses while Present (CC) loop -- If pragma, just analyze it if Nkind (CC) = N_Pragma then Analyze (CC); -- Processing for real component clause else Ccount := Ccount + 1; Posit := Static_Integer (Position (CC)); Fbit := Static_Integer (First_Bit (CC)); Lbit := Static_Integer (Last_Bit (CC)); if Posit /= No_Uint and then Fbit /= No_Uint and then Lbit /= No_Uint then if Posit < 0 then Error_Msg_N ("position cannot be negative", Position (CC)); elsif Fbit < 0 then Error_Msg_N ("first bit cannot be negative", First_Bit (CC)); -- Values look OK, so find the corresponding record component -- Even though the syntax allows an attribute reference for -- implementation-defined components, GNAT does not allow the -- tag to get an explicit position. elsif Nkind (Component_Name (CC)) = N_Attribute_Reference then if Attribute_Name (Component_Name (CC)) = Name_Tag then Error_Msg_N ("position of tag cannot be specified", CC); else Error_Msg_N ("illegal component name", CC); end if; else Comp := First_Entity (Rectype); while Present (Comp) loop exit when Chars (Comp) = Chars (Component_Name (CC)); Next_Entity (Comp); end loop; if No (Comp) then -- Maybe component of base type that is absent from -- statically constrained first subtype. Comp := First_Entity (Base_Type (Rectype)); while Present (Comp) loop exit when Chars (Comp) = Chars (Component_Name (CC)); Next_Entity (Comp); end loop; end if; if No (Comp) then Error_Msg_N ("component clause is for non-existent field", CC); elsif Present (Component_Clause (Comp)) then Error_Msg_Sloc := Sloc (Component_Clause (Comp)); Error_Msg_N ("component clause previously given#", CC); else -- Update Fbit and Lbit to the actual bit number. Fbit := Fbit + UI_From_Int (SSU) * Posit; Lbit := Lbit + UI_From_Int (SSU) * Posit; if Fbit <= Max_Bit_So_Far then Overlap_Check_Required := True; else Max_Bit_So_Far := Lbit; end if; if Has_Size_Clause (Rectype) and then Esize (Rectype) <= Lbit then Error_Msg_N ("bit number out of range of specified size", Last_Bit (CC)); else Set_Component_Clause (Comp, CC); Set_Component_Bit_Offset (Comp, Fbit); Set_Esize (Comp, 1 + (Lbit - Fbit)); Set_Normalized_First_Bit (Comp, Fbit mod SSU); Set_Normalized_Position (Comp, Fbit / SSU); Set_Normalized_Position_Max (Fent, Normalized_Position (Fent)); if Is_Tagged_Type (Rectype) and then Fbit < System_Address_Size then Error_Msg_NE ("component overlaps tag field of&", CC, Rectype); end if; -- Test for large object that is not on a byte -- boundary, defined as a large packed array not -- represented by a modular type, or an object for -- which a size of greater than 64 bits is specified. if Fbit mod SSU /= 0 then if (Is_Packed_Array_Type (Etype (Comp)) and then Is_Array_Type (Packed_Array_Type (Etype (Comp)))) or else Esize (Etype (Comp)) > 64 then Error_Msg_N ("large component must be on byte boundary", First_Bit (CC)); end if; end if; -- This information is also set in the -- corresponding component of the base type, -- found by accessing the Original_Record_Component -- link if it is present. Ocomp := Original_Record_Component (Comp); if Hbit < Lbit then Hbit := Lbit; end if; Check_Size (Component_Name (CC), Etype (Comp), Esize (Comp), Biased); Set_Has_Biased_Representation (Comp, Biased); if Present (Ocomp) then Set_Component_Clause (Ocomp, CC); Set_Component_Bit_Offset (Ocomp, Fbit); Set_Normalized_First_Bit (Ocomp, Fbit mod SSU); Set_Normalized_Position (Ocomp, Fbit / SSU); Set_Esize (Ocomp, 1 + (Lbit - Fbit)); Set_Normalized_Position_Max (Ocomp, Normalized_Position (Ocomp)); Set_Has_Biased_Representation (Ocomp, Has_Biased_Representation (Comp)); end if; if Esize (Comp) < 0 then Error_Msg_N ("component size is negative", CC); end if; end if; end if; end if; end if; end if; Next (CC); end loop; -- Now that we have processed all the component clauses, check for -- overlap. We have to leave this till last, since the components -- can appear in any arbitrary order in the representation clause. -- We do not need this check if all specified ranges were monotonic, -- as recorded by Overlap_Check_Required being False at this stage. -- This first section checks if there are any overlapping entries -- at all. It does this by sorting all entries and then seeing if -- there are any overlaps. If there are none, then that is decisive, -- but if there are overlaps, they may still be OK (they may result -- from fields in different variants). if Overlap_Check_Required then Overlap_Check1 : declare OC_Fbit : array (0 .. Ccount) of Uint; -- First-bit values for component clauses, the value is the -- offset of the first bit of the field from start of record. -- The zero entry is for use in sorting. OC_Lbit : array (0 .. Ccount) of Uint; -- Last-bit values for component clauses, the value is the -- offset of the last bit of the field from start of record. -- The zero entry is for use in sorting. OC_Count : Natural := 0; -- Count of entries in OC_Fbit and OC_Lbit function OC_Lt (Op1, Op2 : Natural) return Boolean; -- Compare routine for Sort (See GNAT.Heap_Sort_A) procedure OC_Move (From : Natural; To : Natural); -- Move routine for Sort (see GNAT.Heap_Sort_A) function OC_Lt (Op1, Op2 : Natural) return Boolean is begin return OC_Fbit (Op1) < OC_Fbit (Op2); end OC_Lt; procedure OC_Move (From : Natural; To : Natural) is begin OC_Fbit (To) := OC_Fbit (From); OC_Lbit (To) := OC_Lbit (From); end OC_Move; begin CC := First (Component_Clauses (N)); while Present (CC) loop if Nkind (CC) /= N_Pragma then Posit := Static_Integer (Position (CC)); Fbit := Static_Integer (First_Bit (CC)); Lbit := Static_Integer (Last_Bit (CC)); if Posit /= No_Uint and then Fbit /= No_Uint and then Lbit /= No_Uint then OC_Count := OC_Count + 1; Posit := Posit * SSU; OC_Fbit (OC_Count) := Fbit + Posit; OC_Lbit (OC_Count) := Lbit + Posit; end if; end if; Next (CC); end loop; Sort (OC_Count, OC_Move'Unrestricted_Access, OC_Lt'Unrestricted_Access); Overlap_Check_Required := False; for J in 1 .. OC_Count - 1 loop if OC_Lbit (J) >= OC_Fbit (J + 1) then Overlap_Check_Required := True; exit; end if; end loop; end Overlap_Check1; end if; -- If Overlap_Check_Required is still True, then we have to do -- the full scale overlap check, since we have at least two fields -- that do overlap, and we need to know if that is OK since they -- are in the same variant, or whether we have a definite problem if Overlap_Check_Required then Overlap_Check2 : declare C1_Ent, C2_Ent : Entity_Id; -- Entities of components being checked for overlap Clist : Node_Id; -- Component_List node whose Component_Items are being checked Citem : Node_Id; -- Component declaration for component being checked begin C1_Ent := First_Entity (Base_Type (Rectype)); -- Loop through all components in record. For each component check -- for overlap with any of the preceding elements on the component -- list containing the component, and also, if the component is in -- a variant, check against components outside the case structure. -- This latter test is repeated recursively up the variant tree. Main_Component_Loop : while Present (C1_Ent) loop if Ekind (C1_Ent) /= E_Component and then Ekind (C1_Ent) /= E_Discriminant then goto Continue_Main_Component_Loop; end if; -- Skip overlap check if entity has no declaration node. This -- happens with discriminants in constrained derived types. -- Probably we are missing some checks as a result, but that -- does not seem terribly serious ??? if No (Declaration_Node (C1_Ent)) then goto Continue_Main_Component_Loop; end if; Clist := Parent (List_Containing (Declaration_Node (C1_Ent))); -- Loop through component lists that need checking. Check the -- current component list and all lists in variants above us. Component_List_Loop : loop -- If derived type definition, go to full declaration -- If at outer level, check discriminants if there are any if Nkind (Clist) = N_Derived_Type_Definition then Clist := Parent (Clist); end if; -- Outer level of record definition, check discriminants if Nkind (Clist) = N_Full_Type_Declaration or else Nkind (Clist) = N_Private_Type_Declaration then if Has_Discriminants (Defining_Identifier (Clist)) then C2_Ent := First_Discriminant (Defining_Identifier (Clist)); while Present (C2_Ent) loop exit when C1_Ent = C2_Ent; Check_Component_Overlap (C1_Ent, C2_Ent); Next_Discriminant (C2_Ent); end loop; end if; -- Record extension case elsif Nkind (Clist) = N_Derived_Type_Definition then Clist := Empty; -- Otherwise check one component list else Citem := First (Component_Items (Clist)); while Present (Citem) loop if Nkind (Citem) = N_Component_Declaration then C2_Ent := Defining_Identifier (Citem); exit when C1_Ent = C2_Ent; Check_Component_Overlap (C1_Ent, C2_Ent); end if; Next (Citem); end loop; end if; -- Check for variants above us (the parent of the Clist can -- be a variant, in which case its parent is a variant part, -- and the parent of the variant part is a component list -- whose components must all be checked against the current -- component for overlap. if Nkind (Parent (Clist)) = N_Variant then Clist := Parent (Parent (Parent (Clist))); -- Check for possible discriminant part in record, this is -- treated essentially as another level in the recursion. -- For this case we have the parent of the component list -- is the record definition, and its parent is the full -- type declaration which contains the discriminant -- specifications. elsif Nkind (Parent (Clist)) = N_Record_Definition then Clist := Parent (Parent ((Clist))); -- If neither of these two cases, we are at the top of -- the tree else exit Component_List_Loop; end if; end loop Component_List_Loop; <> Next_Entity (C1_Ent); end loop Main_Component_Loop; end Overlap_Check2; end if; -- For records that have component clauses for all components, and -- whose size is less than or equal to 32, we need to know the size -- in the front end to activate possible packed array processing -- where the component type is a record. -- At this stage Hbit + 1 represents the first unused bit from all -- the component clauses processed, so if the component clauses are -- complete, then this is the length of the record. -- For records longer than System.Storage_Unit, and for those where -- not all components have component clauses, the back end determines -- the length (it may for example be appopriate to round up the size -- to some convenient boundary, based on alignment considerations etc). if Unknown_RM_Size (Rectype) and then Hbit + 1 <= 32 then -- Nothing to do if at least one component with no component clause Comp := First_Entity (Rectype); while Present (Comp) loop if Ekind (Comp) = E_Component or else Ekind (Comp) = E_Discriminant then if No (Component_Clause (Comp)) then return; end if; end if; Next_Entity (Comp); end loop; -- If we fall out of loop, all components have component clauses -- and so we can set the size to the maximum value. Set_RM_Size (Rectype, Hbit + 1); end if; end Analyze_Record_Representation_Clause; ----------------------------- -- Check_Component_Overlap -- ----------------------------- procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is begin if Present (Component_Clause (C1_Ent)) and then Present (Component_Clause (C2_Ent)) then -- Exclude odd case where we have two tag fields in the same -- record, both at location zero. This seems a bit strange, -- but it seems to happen in some circumstances ??? if Chars (C1_Ent) = Name_uTag and then Chars (C2_Ent) = Name_uTag then return; end if; -- Here we check if the two fields overlap declare S1 : constant Uint := Component_Bit_Offset (C1_Ent); S2 : constant Uint := Component_Bit_Offset (C2_Ent); E1 : constant Uint := S1 + Esize (C1_Ent); E2 : constant Uint := S2 + Esize (C2_Ent); begin if E2 <= S1 or else E1 <= S2 then null; else Error_Msg_Node_2 := Component_Name (Component_Clause (C2_Ent)); Error_Msg_Sloc := Sloc (Error_Msg_Node_2); Error_Msg_Node_1 := Component_Name (Component_Clause (C1_Ent)); Error_Msg_N ("component& overlaps & #", Component_Name (Component_Clause (C1_Ent))); end if; end; end if; end Check_Component_Overlap; ----------------------------------- -- Check_Constant_Address_Clause -- ----------------------------------- procedure Check_Constant_Address_Clause (Expr : Node_Id; U_Ent : Entity_Id) is procedure Check_At_Constant_Address (Nod : Node_Id); -- Checks that the given node N represents a name whose 'Address -- is constant (in the same sense as OK_Constant_Address_Clause, -- i.e. the address value is the same at the point of declaration -- of U_Ent and at the time of elaboration of the address clause. procedure Check_Expr_Constants (Nod : Node_Id); -- Checks that Nod meets the requirements for a constant address -- clause in the sense of the enclosing procedure. procedure Check_List_Constants (Lst : List_Id); -- Check that all elements of list Lst meet the requirements for a -- constant address clause in the sense of the enclosing procedure. ------------------------------- -- Check_At_Constant_Address -- ------------------------------- procedure Check_At_Constant_Address (Nod : Node_Id) is begin if Is_Entity_Name (Nod) then if Present (Address_Clause (Entity ((Nod)))) then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_NE ("address for& cannot" & " depend on another address clause! ('R'M 13.1(22))!", Nod, U_Ent); elsif In_Same_Source_Unit (Entity (Nod), U_Ent) and then Sloc (U_Ent) < Sloc (Entity (Nod)) then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_Name_1 := Chars (Entity (Nod)); Error_Msg_Name_2 := Chars (U_Ent); Error_Msg_N ("\% must be defined before % ('R'M 13.1(22))!", Nod); end if; elsif Nkind (Nod) = N_Selected_Component then declare T : constant Entity_Id := Etype (Prefix (Nod)); begin if (Is_Record_Type (T) and then Has_Discriminants (T)) or else (Is_Access_Type (T) and then Is_Record_Type (Designated_Type (T)) and then Has_Discriminants (Designated_Type (T))) then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_N ("\address cannot depend on component" & " of discriminated record ('R'M 13.1(22))!", Nod); else Check_At_Constant_Address (Prefix (Nod)); end if; end; elsif Nkind (Nod) = N_Indexed_Component then Check_At_Constant_Address (Prefix (Nod)); Check_List_Constants (Expressions (Nod)); else Check_Expr_Constants (Nod); end if; end Check_At_Constant_Address; -------------------------- -- Check_Expr_Constants -- -------------------------- procedure Check_Expr_Constants (Nod : Node_Id) is begin if Nkind (Nod) in N_Has_Etype and then Etype (Nod) = Any_Type then return; end if; case Nkind (Nod) is when N_Empty | N_Error => return; when N_Identifier | N_Expanded_Name => declare Ent : constant Entity_Id := Entity (Nod); Loc_Ent : constant Source_Ptr := Sloc (Ent); Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent); begin if Ekind (Ent) = E_Named_Integer or else Ekind (Ent) = E_Named_Real or else Is_Type (Ent) then return; elsif Ekind (Ent) = E_Constant or else Ekind (Ent) = E_In_Parameter then -- This is the case where we must have Ent defined -- before U_Ent. Clearly if they are in different -- units this requirement is met since the unit -- containing Ent is already processed. if not In_Same_Source_Unit (Ent, U_Ent) then return; -- Otherwise location of Ent must be before the -- location of U_Ent, that's what prior defined means. elsif Loc_Ent < Loc_U_Ent then return; else Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_Name_1 := Chars (Ent); Error_Msg_Name_2 := Chars (U_Ent); Error_Msg_N ("\% must be defined before % ('R'M 13.1(22))!", Nod); end if; elsif Nkind (Original_Node (Nod)) = N_Function_Call then Check_Expr_Constants (Original_Node (Nod)); else Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_Name_1 := Chars (Ent); Error_Msg_N ("\reference to variable% not allowed ('R'M 13.1(22))!", Nod); end if; end; when N_Integer_Literal | N_Real_Literal | N_String_Literal | N_Character_Literal => return; when N_Range => Check_Expr_Constants (Low_Bound (Nod)); Check_Expr_Constants (High_Bound (Nod)); when N_Explicit_Dereference => Check_Expr_Constants (Prefix (Nod)); when N_Indexed_Component => Check_Expr_Constants (Prefix (Nod)); Check_List_Constants (Expressions (Nod)); when N_Slice => Check_Expr_Constants (Prefix (Nod)); Check_Expr_Constants (Discrete_Range (Nod)); when N_Selected_Component => Check_Expr_Constants (Prefix (Nod)); when N_Attribute_Reference => if (Attribute_Name (Nod) = Name_Address or else Attribute_Name (Nod) = Name_Access or else Attribute_Name (Nod) = Name_Unchecked_Access or else Attribute_Name (Nod) = Name_Unrestricted_Access) then Check_At_Constant_Address (Prefix (Nod)); else Check_Expr_Constants (Prefix (Nod)); Check_List_Constants (Expressions (Nod)); end if; when N_Aggregate => Check_List_Constants (Component_Associations (Nod)); Check_List_Constants (Expressions (Nod)); when N_Component_Association => Check_Expr_Constants (Expression (Nod)); when N_Extension_Aggregate => Check_Expr_Constants (Ancestor_Part (Nod)); Check_List_Constants (Component_Associations (Nod)); Check_List_Constants (Expressions (Nod)); when N_Null => return; when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In => Check_Expr_Constants (Left_Opnd (Nod)); Check_Expr_Constants (Right_Opnd (Nod)); when N_Unary_Op => Check_Expr_Constants (Right_Opnd (Nod)); when N_Type_Conversion | N_Qualified_Expression | N_Allocator => Check_Expr_Constants (Expression (Nod)); when N_Unchecked_Type_Conversion => Check_Expr_Constants (Expression (Nod)); -- If this is a rewritten unchecked conversion, subtypes -- in this node are those created within the instance. -- To avoid order of elaboration issues, replace them -- with their base types. Note that address clauses can -- cause order of elaboration problems because they are -- elaborated by the back-end at the point of definition, -- and may mention entities declared in between (as long -- as everything is static). It is user-friendly to allow -- unchecked conversions in this context. if Nkind (Original_Node (Nod)) = N_Function_Call then Set_Etype (Expression (Nod), Base_Type (Etype (Expression (Nod)))); Set_Etype (Nod, Base_Type (Etype (Nod))); end if; when N_Function_Call => if not Is_Pure (Entity (Name (Nod))) then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_NE ("\function & is not pure ('R'M 13.1(22))!", Nod, Entity (Name (Nod))); else Check_List_Constants (Parameter_Associations (Nod)); end if; when N_Parameter_Association => Check_Expr_Constants (Explicit_Actual_Parameter (Nod)); when others => Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_NE ("\must be constant defined before& ('R'M 13.1(22))!", Nod, U_Ent); end case; end Check_Expr_Constants; -------------------------- -- Check_List_Constants -- -------------------------- procedure Check_List_Constants (Lst : List_Id) is Nod1 : Node_Id; begin if Present (Lst) then Nod1 := First (Lst); while Present (Nod1) loop Check_Expr_Constants (Nod1); Next (Nod1); end loop; end if; end Check_List_Constants; -- Start of processing for Check_Constant_Address_Clause begin Check_Expr_Constants (Expr); end Check_Constant_Address_Clause; ---------------- -- Check_Size -- ---------------- procedure Check_Size (N : Node_Id; T : Entity_Id; Siz : Uint; Biased : out Boolean) is UT : constant Entity_Id := Underlying_Type (T); M : Uint; begin Biased := False; -- Immediate return if size is same as standard size or if composite -- item, or generic type, or type with previous errors. if No (UT) or else UT = Any_Type or else Is_Generic_Type (UT) or else Is_Generic_Type (Root_Type (UT)) or else Is_Composite_Type (UT) or else (Known_Esize (UT) and then Siz = Esize (UT)) then return; -- For fixed-point types, don't check minimum if type is not frozen, -- since type is not known till then -- at freeze time. elsif Is_Fixed_Point_Type (UT) and then not Is_Frozen (UT) then null; -- Cases for which a minimum check is required else M := UI_From_Int (Minimum_Size (UT)); if Siz < M then -- Size is less than minimum size, but one possibility remains -- that we can manage with the new size if we bias the type M := UI_From_Int (Minimum_Size (UT, Biased => True)); if Siz < M then Error_Msg_Uint_1 := M; Error_Msg_NE ("size for& too small, minimum allowed is ^", N, T); else Biased := True; end if; end if; end if; end Check_Size; ------------------------- -- Get_Alignment_Value -- ------------------------- function Get_Alignment_Value (Expr : Node_Id) return Uint is Align : constant Uint := Static_Integer (Expr); begin if Align = No_Uint then return No_Uint; elsif Align <= 0 then Error_Msg_N ("alignment value must be positive", Expr); return No_Uint; else for J in Int range 0 .. 64 loop declare M : constant Uint := Uint_2 ** J; begin exit when M = Align; if M > Align then Error_Msg_N ("alignment value must be power of 2", Expr); return No_Uint; end if; end; end loop; return Align; end if; end Get_Alignment_Value; ---------------- -- Initialize -- ---------------- procedure Initialize is begin Unchecked_Conversions.Init; end Initialize; ------------------------- -- Is_Operational_Item -- ------------------------- function Is_Operational_Item (N : Node_Id) return Boolean is begin if Nkind (N) /= N_Attribute_Definition_Clause then return False; else declare Id : constant Attribute_Id := Get_Attribute_Id (Chars (N)); begin return Id = Attribute_Input or else Id = Attribute_Output or else Id = Attribute_Read or else Id = Attribute_Write or else Id = Attribute_External_Tag; end; end if; end Is_Operational_Item; ------------------ -- Minimum_Size -- ------------------ function Minimum_Size (T : Entity_Id; Biased : Boolean := False) return Nat is Lo : Uint := No_Uint; Hi : Uint := No_Uint; LoR : Ureal := No_Ureal; HiR : Ureal := No_Ureal; LoSet : Boolean := False; HiSet : Boolean := False; B : Uint; S : Nat; Ancest : Entity_Id; R_Typ : constant Entity_Id := Root_Type (T); begin -- If bad type, return 0 if T = Any_Type then return 0; -- For generic types, just return zero. There cannot be any legitimate -- need to know such a size, but this routine may be called with a -- generic type as part of normal processing. elsif Is_Generic_Type (R_Typ) or else R_Typ = Any_Type then return 0; -- Access types elsif Is_Access_Type (T) then return System_Address_Size; -- Floating-point types elsif Is_Floating_Point_Type (T) then return UI_To_Int (Esize (R_Typ)); -- Discrete types elsif Is_Discrete_Type (T) then -- The following loop is looking for the nearest compile time -- known bounds following the ancestor subtype chain. The idea -- is to find the most restrictive known bounds information. Ancest := T; loop if Ancest = Any_Type or else Etype (Ancest) = Any_Type then return 0; end if; if not LoSet then if Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then Lo := Expr_Rep_Value (Type_Low_Bound (Ancest)); LoSet := True; exit when HiSet; end if; end if; if not HiSet then if Compile_Time_Known_Value (Type_High_Bound (Ancest)) then Hi := Expr_Rep_Value (Type_High_Bound (Ancest)); HiSet := True; exit when LoSet; end if; end if; Ancest := Ancestor_Subtype (Ancest); if No (Ancest) then Ancest := Base_Type (T); if Is_Generic_Type (Ancest) then return 0; end if; end if; end loop; -- Fixed-point types. We can't simply use Expr_Value to get the -- Corresponding_Integer_Value values of the bounds, since these -- do not get set till the type is frozen, and this routine can -- be called before the type is frozen. Similarly the test for -- bounds being static needs to include the case where we have -- unanalyzed real literals for the same reason. elsif Is_Fixed_Point_Type (T) then -- The following loop is looking for the nearest compile time -- known bounds following the ancestor subtype chain. The idea -- is to find the most restrictive known bounds information. Ancest := T; loop if Ancest = Any_Type or else Etype (Ancest) = Any_Type then return 0; end if; if not LoSet then if Nkind (Type_Low_Bound (Ancest)) = N_Real_Literal or else Compile_Time_Known_Value (Type_Low_Bound (Ancest)) then LoR := Expr_Value_R (Type_Low_Bound (Ancest)); LoSet := True; exit when HiSet; end if; end if; if not HiSet then if Nkind (Type_High_Bound (Ancest)) = N_Real_Literal or else Compile_Time_Known_Value (Type_High_Bound (Ancest)) then HiR := Expr_Value_R (Type_High_Bound (Ancest)); HiSet := True; exit when LoSet; end if; end if; Ancest := Ancestor_Subtype (Ancest); if No (Ancest) then Ancest := Base_Type (T); if Is_Generic_Type (Ancest) then return 0; end if; end if; end loop; Lo := UR_To_Uint (LoR / Small_Value (T)); Hi := UR_To_Uint (HiR / Small_Value (T)); -- No other types allowed else raise Program_Error; end if; -- Fall through with Hi and Lo set. Deal with biased case. if (Biased and then not Is_Fixed_Point_Type (T)) or else Has_Biased_Representation (T) then Hi := Hi - Lo; Lo := Uint_0; end if; -- Signed case. Note that we consider types like range 1 .. -1 to be -- signed for the purpose of computing the size, since the bounds -- have to be accomodated in the base type. if Lo < 0 or else Hi < 0 then S := 1; B := Uint_1; -- S = size, B = 2 ** (size - 1) (can accommodate -B .. +(B - 1)) -- Note that we accommodate the case where the bounds cross. This -- can happen either because of the way the bounds are declared -- or because of the algorithm in Freeze_Fixed_Point_Type. while Lo < -B or else Hi < -B or else Lo >= B or else Hi >= B loop B := Uint_2 ** S; S := S + 1; end loop; -- Unsigned case else -- If both bounds are positive, make sure that both are represen- -- table in the case where the bounds are crossed. This can happen -- either because of the way the bounds are declared, or because of -- the algorithm in Freeze_Fixed_Point_Type. if Lo > Hi then Hi := Lo; end if; -- S = size, (can accommodate 0 .. (2**size - 1)) S := 0; while Hi >= Uint_2 ** S loop S := S + 1; end loop; end if; return S; end Minimum_Size; ------------------------- -- New_Stream_Function -- ------------------------- procedure New_Stream_Function (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : Name_Id) is Loc : constant Source_Ptr := Sloc (N); Subp_Id : Entity_Id; Subp_Decl : Node_Id; F : Entity_Id; Etyp : Entity_Id; function Build_Spec return Node_Id; -- Used for declaration and renaming declaration, so that this is -- treated as a renaming_as_body. ---------------- -- Build_Spec -- ---------------- function Build_Spec return Node_Id is begin Subp_Id := Make_Defining_Identifier (Loc, Nam); return Make_Function_Specification (Loc, Defining_Unit_Name => Subp_Id, Parameter_Specifications => New_List ( Make_Parameter_Specification (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, Name_S), Parameter_Type => Make_Access_Definition (Loc, Subtype_Mark => New_Reference_To ( Designated_Type (Etype (F)), Loc)))), Subtype_Mark => New_Reference_To (Etyp, Loc)); end Build_Spec; -- Start of processing for New_Stream_Function begin F := First_Formal (Subp); Etyp := Etype (Subp); if not Is_Tagged_Type (Ent) then Subp_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Spec); Insert_Action (N, Subp_Decl); end if; Subp_Decl := Make_Subprogram_Renaming_Declaration (Loc, Specification => Build_Spec, Name => New_Reference_To (Subp, Loc)); if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then Set_TSS (Base_Type (Ent), Subp_Id); else Insert_Action (N, Subp_Decl); Copy_TSS (Subp_Id, Base_Type (Ent)); end if; end New_Stream_Function; -------------------------- -- New_Stream_Procedure -- -------------------------- procedure New_Stream_Procedure (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : Name_Id; Out_P : Boolean := False) is Loc : constant Source_Ptr := Sloc (N); Subp_Id : Entity_Id; Subp_Decl : Node_Id; F : Entity_Id; Etyp : Entity_Id; function Build_Spec return Node_Id; -- Used for declaration and renaming declaration, so that this is -- treated as a renaming_as_body. function Build_Spec return Node_Id is begin Subp_Id := Make_Defining_Identifier (Loc, Nam); return Make_Procedure_Specification (Loc, Defining_Unit_Name => Subp_Id, Parameter_Specifications => New_List ( Make_Parameter_Specification (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, Name_S), Parameter_Type => Make_Access_Definition (Loc, Subtype_Mark => New_Reference_To ( Designated_Type (Etype (F)), Loc))), Make_Parameter_Specification (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, Name_V), Out_Present => Out_P, Parameter_Type => New_Reference_To (Etyp, Loc)))); end Build_Spec; -- Start of processing for New_Stream_Function begin F := First_Formal (Subp); Etyp := Etype (Next_Formal (F)); if not Is_Tagged_Type (Ent) then Subp_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Spec); Insert_Action (N, Subp_Decl); end if; Subp_Decl := Make_Subprogram_Renaming_Declaration (Loc, Specification => Build_Spec, Name => New_Reference_To (Subp, Loc)); if Is_Tagged_Type (Ent) and then not Is_Limited_Type (Ent) then Set_TSS (Base_Type (Ent), Subp_Id); else Insert_Action (N, Subp_Decl); Copy_TSS (Subp_Id, Base_Type (Ent)); end if; end New_Stream_Procedure; --------------------- -- Record_Rep_Item -- --------------------- procedure Record_Rep_Item (T : Entity_Id; N : Node_Id) is begin Set_Next_Rep_Item (N, First_Rep_Item (T)); Set_First_Rep_Item (T, N); end Record_Rep_Item; ------------------------ -- Rep_Item_Too_Early -- ------------------------ function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is begin -- Cannot apply rep items that are not operational items -- to generic types if Is_Operational_Item (N) then return False; elsif Is_Type (T) and then Is_Generic_Type (Root_Type (T)) then Error_Msg_N ("representation item not allowed for generic type", N); return True; end if; -- Otherwise check for incompleted type if Is_Incomplete_Or_Private_Type (T) and then No (Underlying_Type (T)) then Error_Msg_N ("representation item must be after full type declaration", N); return True; -- If the type has incompleted components, a representation clause is -- illegal but stream attributes and Convention pragmas are correct. elsif Has_Private_Component (T) then if Nkind (N) = N_Pragma then return False; else Error_Msg_N ("representation item must appear after type is fully defined", N); return True; end if; else return False; end if; end Rep_Item_Too_Early; ----------------------- -- Rep_Item_Too_Late -- ----------------------- function Rep_Item_Too_Late (T : Entity_Id; N : Node_Id; FOnly : Boolean := False) return Boolean is S : Entity_Id; Parent_Type : Entity_Id; procedure Too_Late; -- Output the too late message procedure Too_Late is begin Error_Msg_N ("representation item appears too late!", N); end Too_Late; -- Start of processing for Rep_Item_Too_Late begin -- First make sure entity is not frozen (RM 13.1(9)). Exclude imported -- types, which may be frozen if they appear in a representation clause -- for a local type. if Is_Frozen (T) and then not From_With_Type (T) then Too_Late; S := First_Subtype (T); if Present (Freeze_Node (S)) then Error_Msg_NE ("?no more representation items for }!", Freeze_Node (S), S); end if; return True; -- Check for case of non-tagged derived type whose parent either has -- primitive operations, or is a by reference type (RM 13.1(10)). elsif Is_Type (T) and then not FOnly and then Is_Derived_Type (T) and then not Is_Tagged_Type (T) then Parent_Type := Etype (Base_Type (T)); if Has_Primitive_Operations (Parent_Type) then Too_Late; Error_Msg_NE ("primitive operations already defined for&!", N, Parent_Type); return True; elsif Is_By_Reference_Type (Parent_Type) then Too_Late; Error_Msg_NE ("parent type & is a by reference type!", N, Parent_Type); return True; end if; end if; -- No error, link item into head of chain of rep items for the entity Record_Rep_Item (T, N); return False; end Rep_Item_Too_Late; ------------------------- -- Same_Representation -- ------------------------- function Same_Representation (Typ1, Typ2 : Entity_Id) return Boolean is T1 : constant Entity_Id := Underlying_Type (Typ1); T2 : constant Entity_Id := Underlying_Type (Typ2); begin -- A quick check, if base types are the same, then we definitely have -- the same representation, because the subtype specific representation -- attributes (Size and Alignment) do not affect representation from -- the point of view of this test. if Base_Type (T1) = Base_Type (T2) then return True; elsif Is_Private_Type (Base_Type (T2)) and then Base_Type (T1) = Full_View (Base_Type (T2)) then return True; end if; -- Tagged types never have differing representations if Is_Tagged_Type (T1) then return True; end if; -- Representations are definitely different if conventions differ if Convention (T1) /= Convention (T2) then return False; end if; -- Representations are different if component alignments differ if (Is_Record_Type (T1) or else Is_Array_Type (T1)) and then (Is_Record_Type (T2) or else Is_Array_Type (T2)) and then Component_Alignment (T1) /= Component_Alignment (T2) then return False; end if; -- For arrays, the only real issue is component size. If we know the -- component size for both arrays, and it is the same, then that's -- good enough to know we don't have a change of representation. if Is_Array_Type (T1) then if Known_Component_Size (T1) and then Known_Component_Size (T2) and then Component_Size (T1) = Component_Size (T2) then return True; end if; end if; -- Types definitely have same representation if neither has non-standard -- representation since default representations are always consistent. -- If only one has non-standard representation, and the other does not, -- then we consider that they do not have the same representation. They -- might, but there is no way of telling early enough. if Has_Non_Standard_Rep (T1) then if not Has_Non_Standard_Rep (T2) then return False; end if; else return not Has_Non_Standard_Rep (T2); end if; -- Here the two types both have non-standard representation, and we -- need to determine if they have the same non-standard representation -- For arrays, we simply need to test if the component sizes are the -- same. Pragma Pack is reflected in modified component sizes, so this -- check also deals with pragma Pack. if Is_Array_Type (T1) then return Component_Size (T1) = Component_Size (T2); -- Tagged types always have the same representation, because it is not -- possible to specify different representations for common fields. elsif Is_Tagged_Type (T1) then return True; -- Case of record types elsif Is_Record_Type (T1) then -- Packed status must conform if Is_Packed (T1) /= Is_Packed (T2) then return False; -- Otherwise we must check components. Typ2 maybe a constrained -- subtype with fewer components, so we compare the components -- of the base types. else Record_Case : declare CD1, CD2 : Entity_Id; function Same_Rep return Boolean; -- CD1 and CD2 are either components or discriminants. This -- function tests whether the two have the same representation function Same_Rep return Boolean is begin if No (Component_Clause (CD1)) then return No (Component_Clause (CD2)); else return Present (Component_Clause (CD2)) and then Component_Bit_Offset (CD1) = Component_Bit_Offset (CD2) and then Esize (CD1) = Esize (CD2); end if; end Same_Rep; -- Start processing for Record_Case begin if Has_Discriminants (T1) then CD1 := First_Discriminant (T1); CD2 := First_Discriminant (T2); while Present (CD1) loop if not Same_Rep then return False; else Next_Discriminant (CD1); Next_Discriminant (CD2); end if; end loop; end if; CD1 := First_Component (Underlying_Type (Base_Type (T1))); CD2 := First_Component (Underlying_Type (Base_Type (T2))); while Present (CD1) loop if not Same_Rep then return False; else Next_Component (CD1); Next_Component (CD2); end if; end loop; return True; end Record_Case; end if; -- For enumeration types, we must check each literal to see if the -- representation is the same. Note that we do not permit enumeration -- representation clauses for Character and Wide_Character, so these -- cases were already dealt with. elsif Is_Enumeration_Type (T1) then Enumeration_Case : declare L1, L2 : Entity_Id; begin L1 := First_Literal (T1); L2 := First_Literal (T2); while Present (L1) loop if Enumeration_Rep (L1) /= Enumeration_Rep (L2) then return False; else Next_Literal (L1); Next_Literal (L2); end if; end loop; return True; end Enumeration_Case; -- Any other types have the same representation for these purposes else return True; end if; end Same_Representation; -------------------- -- Set_Enum_Esize -- -------------------- procedure Set_Enum_Esize (T : Entity_Id) is Lo : Uint; Hi : Uint; Sz : Nat; begin Init_Alignment (T); -- Find the minimum standard size (8,16,32,64) that fits Lo := Enumeration_Rep (Entity (Type_Low_Bound (T))); Hi := Enumeration_Rep (Entity (Type_High_Bound (T))); if Lo < 0 then if Lo >= -Uint_2**07 and then Hi < Uint_2**07 then Sz := Standard_Character_Size; -- May be > 8 on some targets elsif Lo >= -Uint_2**15 and then Hi < Uint_2**15 then Sz := 16; elsif Lo >= -Uint_2**31 and then Hi < Uint_2**31 then Sz := 32; else pragma Assert (Lo >= -Uint_2**63 and then Hi < Uint_2**63); Sz := 64; end if; else if Hi < Uint_2**08 then Sz := Standard_Character_Size; -- May be > 8 on some targets elsif Hi < Uint_2**16 then Sz := 16; elsif Hi < Uint_2**32 then Sz := 32; else pragma Assert (Hi < Uint_2**63); Sz := 64; end if; end if; -- That minimum is the proper size unless we have a foreign convention -- and the size required is 32 or less, in which case we bump the size -- up to 32. This is required for C and C++ and seems reasonable for -- all other foreign conventions. if Has_Foreign_Convention (T) and then Esize (T) < Standard_Integer_Size then Init_Esize (T, Standard_Integer_Size); else Init_Esize (T, Sz); end if; end Set_Enum_Esize; ----------------------------------- -- Validate_Unchecked_Conversion -- ----------------------------------- procedure Validate_Unchecked_Conversion (N : Node_Id; Act_Unit : Entity_Id) is Source : Entity_Id; Target : Entity_Id; Vnode : Node_Id; begin -- Obtain source and target types. Note that we call Ancestor_Subtype -- here because the processing for generic instantiation always makes -- subtypes, and we want the original frozen actual types. -- If we are dealing with private types, then do the check on their -- fully declared counterparts if the full declarations have been -- encountered (they don't have to be visible, but they must exist!) Source := Ancestor_Subtype (Etype (First_Formal (Act_Unit))); if Is_Private_Type (Source) and then Present (Underlying_Type (Source)) then Source := Underlying_Type (Source); end if; Target := Ancestor_Subtype (Etype (Act_Unit)); -- If either type is generic, the instantiation happens within a -- generic unit, and there is nothing to check. The proper check -- will happen when the enclosing generic is instantiated. if Is_Generic_Type (Source) or else Is_Generic_Type (Target) then return; end if; if Is_Private_Type (Target) and then Present (Underlying_Type (Target)) then Target := Underlying_Type (Target); end if; -- Source may be unconstrained array, but not target if Is_Array_Type (Target) and then not Is_Constrained (Target) then Error_Msg_N ("unchecked conversion to unconstrained array not allowed", N); return; end if; -- Make entry in unchecked conversion table for later processing -- by Validate_Unchecked_Conversions, which will check sizes and -- alignments (using values set by the back-end where possible). Unchecked_Conversions.Append (New_Val => UC_Entry' (Enode => N, Source => Source, Target => Target)); -- Generate N_Validate_Unchecked_Conversion node for back end if -- the back end needs to perform special validation checks. At the -- current time, only the JVM version requires such checks. if Java_VM then Vnode := Make_Validate_Unchecked_Conversion (Sloc (N)); Set_Source_Type (Vnode, Source); Set_Target_Type (Vnode, Target); Insert_After (N, Vnode); end if; end Validate_Unchecked_Conversion; ------------------------------------ -- Validate_Unchecked_Conversions -- ------------------------------------ procedure Validate_Unchecked_Conversions is begin for N in Unchecked_Conversions.First .. Unchecked_Conversions.Last loop declare T : UC_Entry renames Unchecked_Conversions.Table (N); Enode : constant Node_Id := T.Enode; Source : constant Entity_Id := T.Source; Target : constant Entity_Id := T.Target; Source_Siz : Uint; Target_Siz : Uint; begin -- This validation check, which warns if we have unequal sizes -- for unchecked conversion, and thus potentially implementation -- dependent semantics, is one of the few occasions on which we -- use the official RM size instead of Esize. See description -- in Einfo "Handling of Type'Size Values" for details. if Serious_Errors_Detected = 0 and then Known_Static_RM_Size (Source) and then Known_Static_RM_Size (Target) then Source_Siz := RM_Size (Source); Target_Siz := RM_Size (Target); if Source_Siz /= Target_Siz then Warn_On_Instance := True; Error_Msg_N ("types for unchecked conversion have different sizes?", Enode); if All_Errors_Mode then Error_Msg_Name_1 := Chars (Source); Error_Msg_Uint_1 := Source_Siz; Error_Msg_Name_2 := Chars (Target); Error_Msg_Uint_2 := Target_Siz; Error_Msg_N ("\size of % is ^, size of % is ^?", Enode); Error_Msg_Uint_1 := UI_Abs (Source_Siz - Target_Siz); if Is_Discrete_Type (Source) and then Is_Discrete_Type (Target) then if Source_Siz > Target_Siz then Error_Msg_N ("\^ high order bits of source will be ignored?", Enode); elsif Is_Modular_Integer_Type (Source) then Error_Msg_N ("\source will be extended with ^ high order " & "zero bits?", Enode); else Error_Msg_N ("\source will be extended with ^ high order " & "sign bits?", Enode); end if; elsif Source_Siz < Target_Siz then if Is_Discrete_Type (Target) then if Bytes_Big_Endian then Error_Msg_N ("\target value will include ^ undefined " & "low order bits?", Enode); else Error_Msg_N ("\target value will include ^ undefined " & "high order bits?", Enode); end if; else Error_Msg_N ("\^ trailing bits of target value will be " & "undefined?", Enode); end if; else pragma Assert (Source_Siz > Target_Siz); Error_Msg_N ("\^ trailing bits of source will be ignored?", Enode); end if; end if; Warn_On_Instance := False; end if; end if; -- If both types are access types, we need to check the alignment. -- If the alignment of both is specified, we can do it here. if Serious_Errors_Detected = 0 and then Ekind (Source) in Access_Kind and then Ekind (Target) in Access_Kind and then Target_Strict_Alignment and then Present (Designated_Type (Source)) and then Present (Designated_Type (Target)) then declare D_Source : constant Entity_Id := Designated_Type (Source); D_Target : constant Entity_Id := Designated_Type (Target); begin if Known_Alignment (D_Source) and then Known_Alignment (D_Target) then declare Source_Align : constant Uint := Alignment (D_Source); Target_Align : constant Uint := Alignment (D_Target); begin if Source_Align < Target_Align and then not Is_Tagged_Type (D_Source) then Warn_On_Instance := True; Error_Msg_Uint_1 := Target_Align; Error_Msg_Uint_2 := Source_Align; Error_Msg_Node_2 := D_Source; Error_Msg_NE ("alignment of & (^) is stricter than " & "alignment of & (^)?", Enode, D_Target); if All_Errors_Mode then Error_Msg_N ("\resulting access value may have invalid " & "alignment?", Enode); end if; Warn_On_Instance := False; end if; end; end if; end; end if; end; end loop; end Validate_Unchecked_Conversions; ------------------ -- Warn_Overlay -- ------------------ procedure Warn_Overlay (Expr : Node_Id; Typ : Entity_Id; Nam : Node_Id) is Old : Entity_Id := Empty; Decl : Node_Id; begin if not Address_Clause_Overlay_Warnings then return; end if; if Present (Expr) and then (Has_Non_Null_Base_Init_Proc (Typ) or else Is_Access_Type (Typ)) and then not Is_Imported (Entity (Nam)) then if Nkind (Expr) = N_Attribute_Reference and then Is_Entity_Name (Prefix (Expr)) then Old := Entity (Prefix (Expr)); elsif Is_Entity_Name (Expr) and then Ekind (Entity (Expr)) = E_Constant then Decl := Declaration_Node (Entity (Expr)); if Nkind (Decl) = N_Object_Declaration and then Present (Expression (Decl)) and then Nkind (Expression (Decl)) = N_Attribute_Reference and then Is_Entity_Name (Prefix (Expression (Decl))) then Old := Entity (Prefix (Expression (Decl))); elsif Nkind (Expr) = N_Function_Call then return; end if; -- A function call (most likely to To_Address) is probably not -- an overlay, so skip warning. Ditto if the function call was -- inlined and transformed into an entity. elsif Nkind (Original_Node (Expr)) = N_Function_Call then return; end if; Decl := Next (Parent (Expr)); -- If a pragma Import follows, we assume that it is for the current -- target of the address clause, and skip the warning. if Present (Decl) and then Nkind (Decl) = N_Pragma and then Chars (Decl) = Name_Import then return; end if; if Present (Old) then Error_Msg_Node_2 := Old; Error_Msg_N ("default initialization of & may modify &?", Nam); else Error_Msg_N ("default initialization of & may modify overlaid storage?", Nam); end if; -- Add friendly warning if initialization comes from a packed array -- component. if Is_Record_Type (Typ) then declare Comp : Entity_Id; begin Comp := First_Component (Typ); while Present (Comp) loop if Nkind (Parent (Comp)) = N_Component_Declaration and then Present (Expression (Parent (Comp))) then exit; elsif Is_Array_Type (Etype (Comp)) and then Present (Packed_Array_Type (Etype (Comp))) then Error_Msg_NE ("packed array component& will be initialized to zero?", Nam, Comp); exit; else Next_Component (Comp); end if; end loop; end; end if; Error_Msg_N ("use pragma Import for & to " & "suppress initialization ('R'M B.1(24))?", Nam); end if; end Warn_Overlay; end Sem_Ch13;