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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 1 3 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2009, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with 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 Lib; use Lib; with Lib.Xref; use Lib.Xref; with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Ch3; use Sem_Ch3; 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 Sem_Warn; use Sem_Warn; with Snames; use Snames; with Stand; use Stand; with Sinfo; use Sinfo; with Table; with Targparm; use Targparm; with Ttypes; use Ttypes; with Tbuild; use Tbuild; with Urealp; use Urealp; with GNAT.Heap_Sort_G; 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 alignment 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 have 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_Subprogram (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : TSS_Name_Type); -- Create a subprogram 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. 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. Nam indicates the name of the TSS -- function to be generated. -- -- 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. ---------------------------------------------- -- 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 performed by the back end. -- Note: the reason we store a Source_Ptr value instead of a Node_Id -- is that by the time Validate_Unchecked_Conversions is called, Sprint -- will already have modified all Sloc values if the -gnatD option is set. type UC_Entry is record Eloc : Source_Ptr; -- 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"); ---------------------------------------- -- Table for Validate_Address_Clauses -- ---------------------------------------- -- If an address clause has the form -- for X'Address use Expr -- where Expr is of the form Y'Address or recursively is a reference -- to a constant of either of these forms, and X and Y are entities of -- objects, then if Y has a smaller alignment than X, that merits a -- warning about possible bad alignment. The following table collects -- address clauses of this kind. We put these in a table so that they -- can be checked after the back end has completed annotation of the -- alignments of objects, since we can catch more cases that way. type Address_Clause_Check_Record is record N : Node_Id; -- The address clause X : Entity_Id; -- The entity of the object overlaying Y Y : Entity_Id; -- The entity of the object being overlaid Off : Boolean; -- Whether the address is offseted within Y end record; package Address_Clause_Checks is new Table.Table ( Table_Component_Type => Address_Clause_Check_Record, Table_Index_Type => Int, Table_Low_Bound => 1, Table_Initial => 20, Table_Increment => 200, Table_Name => "Address_Clause_Checks"); ----------------------------------------- -- Adjust_Record_For_Reverse_Bit_Order -- ----------------------------------------- procedure Adjust_Record_For_Reverse_Bit_Order (R : Entity_Id) is Max_Machine_Scalar_Size : constant Uint := UI_From_Int (Standard_Long_Long_Integer_Size); -- We use this as the maximum machine scalar size in the sense of AI-133 Num_CC : Natural; Comp : Entity_Id; SSU : constant Uint := UI_From_Int (System_Storage_Unit); begin -- This first loop through components does two things. First it deals -- with the case of components with component clauses whose length is -- greater than the maximum machine scalar size (either accepting them -- or rejecting as needed). Second, it counts the number of components -- with component clauses whose length does not exceed this maximum for -- later processing. Num_CC := 0; Comp := First_Component_Or_Discriminant (R); while Present (Comp) loop declare CC : constant Node_Id := Component_Clause (Comp); begin if Present (CC) then declare Fbit : constant Uint := Static_Integer (First_Bit (CC)); begin -- Case of component with size > max machine scalar if Esize (Comp) > Max_Machine_Scalar_Size then -- Must begin on byte boundary if Fbit mod SSU /= 0 then Error_Msg_N ("illegal first bit value for reverse bit order", First_Bit (CC)); Error_Msg_Uint_1 := SSU; Error_Msg_Uint_2 := Max_Machine_Scalar_Size; Error_Msg_N ("\must be a multiple of ^ if size greater than ^", First_Bit (CC)); -- Must end on byte boundary elsif Esize (Comp) mod SSU /= 0 then Error_Msg_N ("illegal last bit value for reverse bit order", Last_Bit (CC)); Error_Msg_Uint_1 := SSU; Error_Msg_Uint_2 := Max_Machine_Scalar_Size; Error_Msg_N ("\must be a multiple of ^ if size greater than ^", Last_Bit (CC)); -- OK, give warning if enabled elsif Warn_On_Reverse_Bit_Order then Error_Msg_N ("multi-byte field specified with non-standard" & " Bit_Order?", CC); if Bytes_Big_Endian then Error_Msg_N ("\bytes are not reversed " & "(component is big-endian)?", CC); else Error_Msg_N ("\bytes are not reversed " & "(component is little-endian)?", CC); end if; end if; -- Case where size is not greater than max machine -- scalar. For now, we just count these. else Num_CC := Num_CC + 1; end if; end; end if; end; Next_Component_Or_Discriminant (Comp); end loop; -- We need to sort the component clauses on the basis of the Position -- values in the clause, so we can group clauses with the same Position. -- together to determine the relevant machine scalar size. declare Comps : array (0 .. Num_CC) of Entity_Id; -- Array to collect component and discriminant entities. The data -- starts at index 1, the 0'th entry is for the sort routine. function CP_Lt (Op1, Op2 : Natural) return Boolean; -- Compare routine for Sort procedure CP_Move (From : Natural; To : Natural); -- Move routine for Sort package Sorting is new GNAT.Heap_Sort_G (CP_Move, CP_Lt); Start : Natural; Stop : Natural; -- Start and stop positions in component list of set of components -- with the same starting position (that constitute components in -- a single machine scalar). MaxL : Uint; -- Maximum last bit value of any component in this set MSS : Uint; -- Corresponding machine scalar size ----------- -- CP_Lt -- ----------- function CP_Lt (Op1, Op2 : Natural) return Boolean is begin return Position (Component_Clause (Comps (Op1))) < Position (Component_Clause (Comps (Op2))); end CP_Lt; ------------- -- CP_Move -- ------------- procedure CP_Move (From : Natural; To : Natural) is begin Comps (To) := Comps (From); end CP_Move; begin -- Collect the component clauses Num_CC := 0; Comp := First_Component_Or_Discriminant (R); while Present (Comp) loop if Present (Component_Clause (Comp)) and then Esize (Comp) <= Max_Machine_Scalar_Size then Num_CC := Num_CC + 1; Comps (Num_CC) := Comp; end if; Next_Component_Or_Discriminant (Comp); end loop; -- Sort by ascending position number Sorting.Sort (Num_CC); -- We now have all the components whose size does not exceed the max -- machine scalar value, sorted by starting position. In this loop -- we gather groups of clauses starting at the same position, to -- process them in accordance with Ada 2005 AI-133. Stop := 0; while Stop < Num_CC loop Start := Stop + 1; Stop := Start; MaxL := Static_Integer (Last_Bit (Component_Clause (Comps (Start)))); while Stop < Num_CC loop if Static_Integer (Position (Component_Clause (Comps (Stop + 1)))) = Static_Integer (Position (Component_Clause (Comps (Stop)))) then Stop := Stop + 1; MaxL := UI_Max (MaxL, Static_Integer (Last_Bit (Component_Clause (Comps (Stop))))); else exit; end if; end loop; -- Now we have a group of component clauses from Start to Stop -- whose positions are identical, and MaxL is the maximum last bit -- value of any of these components. -- We need to determine the corresponding machine scalar size. -- This loop assumes that machine scalar sizes are even, and that -- each possible machine scalar has twice as many bits as the -- next smaller one. MSS := Max_Machine_Scalar_Size; while MSS mod 2 = 0 and then (MSS / 2) >= SSU and then (MSS / 2) > MaxL loop MSS := MSS / 2; end loop; -- Here is where we fix up the Component_Bit_Offset value to -- account for the reverse bit order. Some examples of what needs -- to be done for the case of a machine scalar size of 8 are: -- First_Bit .. Last_Bit Component_Bit_Offset -- old new old new -- 0 .. 0 7 .. 7 0 7 -- 0 .. 1 6 .. 7 0 6 -- 0 .. 2 5 .. 7 0 5 -- 0 .. 7 0 .. 7 0 4 -- 1 .. 1 6 .. 6 1 6 -- 1 .. 4 3 .. 6 1 3 -- 4 .. 7 0 .. 3 4 0 -- The general rule is that the first bit is obtained by -- subtracting the old ending bit from machine scalar size - 1. for C in Start .. Stop loop declare Comp : constant Entity_Id := Comps (C); CC : constant Node_Id := Component_Clause (Comp); LB : constant Uint := Static_Integer (Last_Bit (CC)); NFB : constant Uint := MSS - Uint_1 - LB; NLB : constant Uint := NFB + Esize (Comp) - 1; Pos : constant Uint := Static_Integer (Position (CC)); begin if Warn_On_Reverse_Bit_Order then Error_Msg_Uint_1 := MSS; Error_Msg_N ("info: reverse bit order in machine " & "scalar of length^?", First_Bit (CC)); Error_Msg_Uint_1 := NFB; Error_Msg_Uint_2 := NLB; if Bytes_Big_Endian then Error_Msg_NE ("?\info: big-endian range for " & "component & is ^ .. ^", First_Bit (CC), Comp); else Error_Msg_NE ("?\info: little-endian range " & "for component & is ^ .. ^", First_Bit (CC), Comp); end if; end if; Set_Component_Bit_Offset (Comp, Pos * SSU + NFB); Set_Normalized_First_Bit (Comp, NFB mod SSU); end; end loop; end loop; end; end Adjust_Record_For_Reverse_Bit_Order; -------------------------------------- -- 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 CS : constant Boolean := Comes_From_Source (N); begin -- This is an obsolescent feature Check_Restriction (No_Obsolescent_Features, N); if Warn_On_Obsolescent_Feature then Error_Msg_N ("at clause is an obsolescent feature (RM J.7(2))?", N); Error_Msg_N ("\use address attribute definition clause instead?", N); end if; -- Rewrite as address clause Rewrite (N, Make_Attribute_Definition_Clause (Sloc (N), Name => Identifier (N), Chars => Name_Address, Expression => Expression (N))); -- We preserve Comes_From_Source, since logically the clause still -- comes from the source program even though it is changed in form. Set_Comes_From_Source (N, CS); -- Analyze rewritten clause 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. procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type); -- Common processing for 'Read, 'Write, 'Input and 'Output attribute -- definition clauses. ----------------------------------- -- Analyze_Stream_TSS_Definition -- ----------------------------------- procedure Analyze_Stream_TSS_Definition (TSS_Nam : TSS_Name_Type) is Subp : Entity_Id := Empty; I : Interp_Index; It : Interp; Pnam : Entity_Id; Is_Read : constant Boolean := (TSS_Nam = TSS_Stream_Read); function Has_Good_Profile (Subp : Entity_Id) return Boolean; -- Return true if the entity is a subprogram with an appropriate -- profile for the attribute being defined. ---------------------- -- Has_Good_Profile -- ---------------------- function Has_Good_Profile (Subp : Entity_Id) return Boolean is F : Entity_Id; Is_Function : constant Boolean := (TSS_Nam = TSS_Stream_Input); Expected_Ekind : constant array (Boolean) of Entity_Kind := (False => E_Procedure, True => E_Function); Typ : Entity_Id; begin if Ekind (Subp) /= Expected_Ekind (Is_Function) then return False; end if; F := First_Formal (Subp); if No (F) or else Ekind (Etype (F)) /= E_Anonymous_Access_Type or else Designated_Type (Etype (F)) /= Class_Wide_Type (RTE (RE_Root_Stream_Type)) then return False; end if; if not Is_Function then Next_Formal (F); declare Expected_Mode : constant array (Boolean) of Entity_Kind := (False => E_In_Parameter, True => E_Out_Parameter); begin if Parameter_Mode (F) /= Expected_Mode (Is_Read) then return False; end if; end; Typ := Etype (F); else Typ := Etype (Subp); end if; return Base_Type (Typ) = Base_Type (Ent) and then No (Next_Formal (F)); end Has_Good_Profile; -- Start of processing for Analyze_Stream_TSS_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), TSS_Nam); -- If Pnam is present, it can be either inherited from an ancestor -- type (in which case it is legal to redefine it for this type), or -- be a previous definition of the attribute for the same type (in -- which case it is illegal). -- In the first case, it will have been analyzed already, and we -- can check that its profile does not match the expected profile -- for a stream attribute of U_Ent. In the second case, either Pnam -- has been analyzed (and has the expected profile), or it has not -- been analyzed yet (case of a type that has not been frozen yet -- and for which the stream attribute has been set using Set_TSS). if Present (Pnam) and then (No (First_Entity (Pnam)) or else Has_Good_Profile (Pnam)) then Error_Msg_Sloc := Sloc (Pnam); Error_Msg_Name_1 := Attr; Error_Msg_N ("% 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 if Is_Abstract_Subprogram (Subp) then Error_Msg_N ("stream subprogram must not be abstract", Expr); return; end if; Set_Entity (Expr, Subp); Set_Etype (Expr, Etype (Subp)); New_Stream_Subprogram (N, U_Ent, Subp, TSS_Nam); else Error_Msg_Name_1 := Attr; Error_Msg_N ("incorrect expression for% attribute", Expr); end if; end Analyze_Stream_TSS_Definition; -- Start of processing for Analyze_Attribute_Definition_Clause begin -- Process Ignore_Rep_Clauses option if Ignore_Rep_Clauses then case Id is -- The following should be ignored. They do not affect legality -- and may be target dependent. The basic idea of -gnatI is to -- ignore any rep clauses that may be target dependent but do not -- affect legality (except possibly to be rejected because they -- are incompatible with the compilation target). when Attribute_Alignment | Attribute_Bit_Order | Attribute_Component_Size | Attribute_Machine_Radix | Attribute_Object_Size | Attribute_Size | Attribute_Small | Attribute_Stream_Size | Attribute_Value_Size => Rewrite (N, Make_Null_Statement (Sloc (N))); return; -- The following should not be ignored, because in the first place -- they are reasonably portable, and should not cause problems in -- compiling code from another target, and also they do affect -- legality, e.g. failing to provide a stream attribute for a -- type may make a program illegal. when Attribute_External_Tag | Attribute_Input | Attribute_Output | Attribute_Read | Attribute_Storage_Pool | Attribute_Storage_Size | Attribute_Write => null; -- Other cases are errors, which will be caught below when others => null; end case; end if; 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 -- The attribute applies to the full view, set the entity of the -- attribute definition accordingly. Ent := Underlying_Type (Ent); U_Ent := Ent; Set_Entity (Nam, 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 -- A little error check, catch for X'Address use X'Address; if Nkind (Nam) = N_Identifier and then Nkind (Expr) = N_Attribute_Reference and then Attribute_Name (Expr) = Name_Address and then Nkind (Prefix (Expr)) = N_Identifier and then Chars (Nam) = Chars (Prefix (Expr)) then Error_Msg_NE ("address for & is self-referencing", Prefix (Expr), Ent); return; end if; -- Not that special case, carry on with analysis of expression Analyze_And_Resolve (Expr, RTE (RE_Address)); -- Even when ignoring rep clauses we need to indicate that the -- entity has an address clause and thus it is legal to declare -- it imported. if Ignore_Rep_Clauses then if Ekind (U_Ent) = E_Variable or else Ekind (U_Ent) = E_Constant then Record_Rep_Item (U_Ent, N); end if; return; end if; 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); return; 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); return; end if; -- For entries, we require a constant address Check_Constant_Address_Clause (Expr, U_Ent); -- Special checks for task types 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; -- Entry address clauses are obsolescent Check_Restriction (No_Obsolescent_Features, N); if Warn_On_Obsolescent_Feature then Error_Msg_N ("attaching interrupt to task entry is an " & "obsolescent feature (RM J.7.1)?", N); Error_Msg_N ("\use interrupt procedure instead?", N); end if; -- Case of an address clause for a controlled object which we -- consider to be erroneous. elsif Is_Controlled (Etype (U_Ent)) or else Has_Controlled_Component (Etype (U_Ent)) then Error_Msg_NE ("?controlled object& must not be overlaid", Nam, U_Ent); Error_Msg_N ("\?Program_Error will be raised at run time", Nam); Insert_Action (Declaration_Node (U_Ent), Make_Raise_Program_Error (Loc, Reason => PE_Overlaid_Controlled_Object)); return; -- Case of address clause for a (non-controlled) object elsif Ekind (U_Ent) = E_Variable or else Ekind (U_Ent) = E_Constant then declare Expr : constant Node_Id := Expression (N); O_Ent : Entity_Id; Off : Boolean; 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); return; end if; Find_Overlaid_Entity (N, O_Ent, Off); -- Overlaying controlled objects is erroneous if Present (O_Ent) and then (Has_Controlled_Component (Etype (O_Ent)) or else Is_Controlled (Etype (O_Ent))) then Error_Msg_N ("?cannot overlay with controlled object", Expr); Error_Msg_N ("\?Program_Error will be raised at run time", Expr); Insert_Action (Declaration_Node (U_Ent), Make_Raise_Program_Error (Loc, Reason => PE_Overlaid_Controlled_Object)); return; elsif Present (O_Ent) and then Ekind (U_Ent) = E_Constant and then not Is_Constant_Object (O_Ent) then Error_Msg_N ("constant overlays a variable?", Expr); elsif Present (Renamed_Object (U_Ent)) then Error_Msg_N ("address clause not allowed" & " for a renaming declaration (RM 13.1(6))", Nam); return; -- 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, Sure => False); -- Here we are checking for explicit overlap of one variable -- by another, and if we find this then mark the overlapped -- variable as also being volatile to prevent unwanted -- optimizations. This is a significant pessimization so -- avoid it when there is an offset, i.e. when the object -- is composite; they cannot be optimized easily anyway. if Present (O_Ent) and then Is_Object (O_Ent) and then not Off then Set_Treat_As_Volatile (O_Ent); end if; -- Legality checks on the address clause for initialized -- objects is deferred until the freeze point, because -- a subsequent pragma might indicate that the object is -- imported and thus not initialized. Set_Has_Delayed_Freeze (U_Ent); -- If an initialization call has been generated for this -- object, it needs to be deferred to after the freeze node -- we have just now added, otherwise GIGI will see a -- reference to the variable (as actual to the IP call) -- before its definition. declare Init_Call : constant Node_Id := Find_Init_Call (U_Ent, N); begin if Present (Init_Call) then Remove (Init_Call); Append_Freeze_Action (U_Ent, Init_Call); end if; end; 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; -- Entity has delayed freeze, so we will generate an -- alignment check at the freeze point unless suppressed. if not Range_Checks_Suppressed (U_Ent) and then not Alignment_Checks_Suppressed (U_Ent) then Set_Check_Address_Alignment (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); -- If the address clause is of the form: -- for Y'Address use X'Address -- or -- Const : constant Address := X'Address; -- ... -- for Y'Address use Const; -- then we make an entry in the table for checking the size -- and alignment of the overlaying variable. We defer this -- check till after code generation to take full advantage -- of the annotation done by the back end. This entry is -- only made if the address clause comes from source. if Address_Clause_Overlay_Warnings and then Comes_From_Source (N) and then Present (O_Ent) and then Is_Object (O_Ent) then Address_Clause_Checks.Append ((N, U_Ent, O_Ent, Off)); -- If variable overlays a constant view, and we are -- warning on overlays, then mark the variable as -- overlaying a constant (we will give warnings later -- if this variable is assigned). if Is_Constant_Object (O_Ent) and then Ekind (U_Ent) = E_Variable then Set_Overlays_Constant (U_Ent); end if; end if; 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 : declare Align : constant 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); -- For an array type, U_Ent is the first subtype. In that case, -- also set the alignment of the anonymous base type so that -- other subtypes (such as the itypes for aggregates of the -- type) also receive the expected alignment. if Is_Array_Type (U_Ent) then Set_Alignment (Base_Type (U_Ent), Align); end if; end if; end Alignment; --------------- -- 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 Flag_Non_Static_Expr ("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 clause 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. Note that component size clauses -- are ignored in VM mode. if VM_Target = No_VM then 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); if Warn_On_Biased_Representation then Error_Msg_N ("?component size clause forces biased " & "representation", N); end if; end if; Set_Component_Size (Btype, Csize); -- For VM case, we ignore component size clauses else -- Give a warning unless we are in GNAT mode, in which case -- the warning is suppressed since it is not useful. if not GNAT_Mode then Error_Msg_N ("?component size ignored in this configuration", N); end if; end if; 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 Flag_Non_Static_Expr ("static string required for tag name!", Nam); end if; if VM_Target = No_VM then Set_Has_External_Tag_Rep_Clause (U_Ent); else Error_Msg_Name_1 := Attr; Error_Msg_N ("% attribute unsupported in this configuration", Nam); end if; if not Is_Library_Level_Entity (U_Ent) then Error_Msg_NE ("?non-unique external tag supplied for &", N, U_Ent); Error_Msg_N ("?\same external tag applies to all subprogram calls", N); Error_Msg_N ("?\corresponding internal tag cannot be obtained", N); end if; end External_Tag; ----------- -- Input -- ----------- when Attribute_Input => Analyze_Stream_TSS_Definition (TSS_Stream_Input); Set_Has_Specified_Stream_Input (Ent); ------------------- -- 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; pragma Warnings (Off, Biased); 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 => Analyze_Stream_TSS_Definition (TSS_Stream_Output); Set_Has_Specified_Stream_Output (Ent); ---------- -- Read -- ---------- when Attribute_Read => Analyze_Stream_TSS_Definition (TSS_Stream_Read); Set_Has_Specified_Stream_Read (Ent); ---------- -- 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 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); if Biased and Warn_On_Biased_Representation then Error_Msg_N ("?size clause forces biased representation", N); end if; 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 if Is_Elementary_Type (Etyp) then if Size /= System_Storage_Unit and then Size /= System_Storage_Unit * 2 and then Size /= System_Storage_Unit * 4 and then Size /= System_Storage_Unit * 8 then Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit); Error_Msg_Uint_2 := Error_Msg_Uint_1 * 8; Error_Msg_N ("size for primitive object must be a power of 2" & " in the range ^-^", N); end if; end if; 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 Flag_Non_Static_Expr ("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_Pool -- ------------------ -- Storage_Pool attribute definition clause when Attribute_Storage_Pool => Storage_Pool : declare Pool : Entity_Id; T : Entity_Id; begin if Ekind (U_Ent) = E_Access_Subprogram_Type then Error_Msg_N ("storage pool cannot be given for access-to-subprogram type", Nam); return; elsif 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 not Denotes_Variable (Expr) then Error_Msg_N ("storage pool must be a variable", Expr); return; end if; if Nkind (Expr) = N_Type_Conversion then T := Etype (Expression (Expr)); else T := Etype (Expr); end if; -- The Stack_Bounded_Pool is used internally for implementing -- access types with a Storage_Size. Since it only work -- properly when used on one specific type, we need to check -- that it is not hijacked improperly: -- type T is access Integer; -- for T'Storage_Size use n; -- type Q is access Float; -- for Q'Storage_Size use T'Storage_Size; -- incorrect if RTE_Available (RE_Stack_Bounded_Pool) and then Base_Type (T) = RTE (RE_Stack_Bounded_Pool) then Error_Msg_N ("non-shareable internal Pool", Expr); return; end if; -- 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; Set_Associated_Storage_Pool (U_Ent, Pool); 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)); Set_Associated_Storage_Pool (U_Ent, Pool); else Error_Msg_N ("incorrect reference to a Storage Pool", Expr); return; end if; end Storage_Pool; ------------------ -- 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 Check_Restriction (No_Obsolescent_Features, N); if Warn_On_Obsolescent_Feature then Error_Msg_N ("storage size clause for task is an " & "obsolescent feature (RM J.9)?", N); Error_Msg_N ("\use Storage_Size pragma instead?", N); end if; 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; ----------------- -- Stream_Size -- ----------------- when Attribute_Stream_Size => Stream_Size : declare Size : constant Uint := Static_Integer (Expr); begin if Ada_Version <= Ada_95 then Check_Restriction (No_Implementation_Attributes, N); end if; if Has_Stream_Size_Clause (U_Ent) then Error_Msg_N ("Stream_Size already given for &", Nam); elsif Is_Elementary_Type (U_Ent) then if Size /= System_Storage_Unit and then Size /= System_Storage_Unit * 2 and then Size /= System_Storage_Unit * 4 and then Size /= System_Storage_Unit * 8 then Error_Msg_Uint_1 := UI_From_Int (System_Storage_Unit); Error_Msg_N ("stream size for elementary type must be a" & " power of 2 and at least ^", N); elsif RM_Size (U_Ent) > Size then Error_Msg_Uint_1 := RM_Size (U_Ent); Error_Msg_N ("stream size for elementary type must be a" & " power of 2 and at least ^", N); end if; Set_Has_Stream_Size_Clause (U_Ent); else Error_Msg_N ("Stream_Size cannot be given for &", Nam); end if; end Stream_Size; ---------------- -- 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); elsif Is_Array_Type (U_Ent) and then not Is_Constrained (U_Ent) then Error_Msg_N ("Value_Size cannot be given for unconstrained array", Nam); else if Is_Elementary_Type (U_Ent) then Check_Size (Expr, U_Ent, Size, Biased); Set_Has_Biased_Representation (U_Ent, Biased); if Biased and Warn_On_Biased_Representation then Error_Msg_N ("?value size clause forces biased representation", N); end if; end if; Set_RM_Size (U_Ent, Size); end if; end Value_Size; ----------- -- Write -- ----------- when Attribute_Write => Analyze_Stream_TSS_Definition (TSS_Stream_Write); Set_Has_Specified_Stream_Write (Ent); -- 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; Check_Code_Statement (N); -- 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 not Nkind_In (DeclO, N_Pragma, N_Use_Package_Clause, N_Use_Type_Clause, 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 not Nkind_In (StmtO, N_Pragma, N_Label, 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 if Ignore_Rep_Clauses then return; end if; -- 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; -- Ignore rep clause on generic actual type. This will already have -- been flagged on the template as an error, and this is the safest -- way to ensure we don't get a junk cascaded message in the instance. if Is_Generic_Actual_Type (Enumtype) then return; -- Type must be in current scope elsif Scope (Enumtype) /= Current_Scope then Error_Msg_N ("type must be declared in this scope", Ident); return; -- Type must be a first subtype elsif not Is_First_Subtype (Enumtype) then Error_Msg_N ("cannot give enumeration rep clause for subtype", N); return; -- Ignore duplicate rep clause elsif Has_Enumeration_Rep_Clause (Enumtype) then Error_Msg_N ("duplicate enumeration rep clause ignored", N); return; -- Don't allow rep clause for standard [wide_[wide_]]character elsif Is_Standard_Character_Type (Enumtype) then Error_Msg_N ("enumeration rep clause not allowed for this type", N); return; -- Check that the expression is a proper aggregate (no parentheses) elsif Paren_Count (Aggr) /= 0 then Error_Msg ("extra parentheses surrounding aggregate not allowed", First_Sloc (Aggr)); return; -- All tests passed, so set rep clause in place 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) 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); -- Err signals that we found some incorrect entries processing -- the list. The final checks for completeness and ordering are -- skipped in this case. 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 Flag_Non_Static_Expr ("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_Freeze_Entity -- --------------------------- procedure Analyze_Freeze_Entity (N : Node_Id) is E : constant Entity_Id := Entity (N); begin -- For tagged types covering interfaces add internal entities that link -- the primitives of the interfaces with the primitives that cover them. -- Note: These entities were originally generated only when generating -- code because their main purpose was to provide support to initialize -- the secondary dispatch tables. They are now generated also when -- compiling with no code generation to provide ASIS the relationship -- between interface primitives and tagged type primitives. if Ada_Version >= Ada_05 and then Ekind (E) = E_Record_Type and then Is_Tagged_Type (E) and then not Is_Interface (E) and then Has_Interfaces (E) then Add_Internal_Interface_Entities (E); end if; end Analyze_Freeze_Entity; ------------------------------------------ -- 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; Pcomp : Entity_Id; Biased : Boolean; Max_Bit_So_Far : Uint; -- Records the maximum bit position so far. If all field positions -- are monotonically increasing, then we can skip the circuit for -- checking for overlap, since no overlap is possible. Tagged_Parent : Entity_Id := Empty; -- This is set in the case of a derived tagged type for which we have -- Is_Fully_Repped_Tagged_Type True (indicating that all components are -- positioned by record representation clauses). In this case we must -- check for overlap between components of this tagged type, and the -- components of its parent. Tagged_Parent will point to this parent -- type. For all other cases Tagged_Parent is left set to Empty. Parent_Last_Bit : Uint; -- Relevant only if Tagged_Parent is set, Parent_Last_Bit indicates the -- last bit position for any field in the parent type. We only need to -- check overlap for fields starting below this point. 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 CR_Pragma : Node_Id := Empty; -- Points to N_Pragma node if Complete_Representation pragma present begin if Ignore_Rep_Clauses then return; end if; 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); AtM_Nod : Node_Id; Mod_Val : Uint; pragma Warnings (Off, Mod_Val); begin Check_Restriction (No_Obsolescent_Features, Mod_Clause (N)); if Warn_On_Obsolescent_Feature then Error_Msg_N ("mod clause is an obsolescent feature (RM J.8)?", N); Error_Msg_N ("\use alignment attribute definition clause instead?", N); end if; if Present (P) then Analyze_List (P); end if; -- In ASIS_Mode 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. -- This seems dubious, this destroys the source tree in a manner -- not detectable by ASIS ??? if Operating_Mode = Check_Semantics and then ASIS_Mode 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; -- For untagged types, clear any existing component clauses for the -- type. If the type is derived, this is what allows us to override -- a rep clause for the parent. For type extensions, the representation -- of the inherited components is inherited, so we want to keep previous -- component clauses for completeness. if not Is_Tagged_Type (Rectype) then Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop Set_Component_Clause (Comp, Empty); Next_Component_Or_Discriminant (Comp); end loop; end if; -- See if we have a fully repped derived tagged type declare PS : constant Entity_Id := Parent_Subtype (Rectype); begin if Present (PS) and then Is_Fully_Repped_Tagged_Type (PS) then Tagged_Parent := PS; -- Find maximum bit of any component of the parent type Parent_Last_Bit := UI_From_Int (System_Address_Size - 1); Pcomp := First_Entity (Tagged_Parent); while Present (Pcomp) loop if Ekind (Pcomp) = E_Discriminant or else Ekind (Pcomp) = E_Component then if Component_Bit_Offset (Pcomp) /= No_Uint and then Known_Static_Esize (Pcomp) then Parent_Last_Bit := UI_Max (Parent_Last_Bit, Component_Bit_Offset (Pcomp) + Esize (Pcomp) - 1); end if; Next_Entity (Pcomp); end if; end loop; end if; end; -- 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). Fent := First_Entity (Rectype); 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 -- Pragma if Nkind (CC) = N_Pragma then Analyze (CC); -- The only pragma of interest is Complete_Representation if Pragma_Name (CC) = Name_Complete_Representation then CR_Pragma := CC; end if; -- 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)); -- The Last_Bit specified in a component clause must not be -- less than the First_Bit minus one (RM-13.5.1(10)). elsif Lbit < Fbit - 1 then Error_Msg_N ("last bit cannot be less than first bit minus one", Last_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 -- Diagnose duplicate rep clause, or check consistency -- if this is an inherited component. In a double fault, -- there may be a duplicate inconsistent clause for an -- inherited component. if Scope (Original_Record_Component (Comp)) = Rectype or else Parent (Component_Clause (Comp)) = N then Error_Msg_Sloc := Sloc (Component_Clause (Comp)); Error_Msg_N ("component clause previously given#", CC); else declare Rep1 : constant Node_Id := Component_Clause (Comp); begin if Intval (Position (Rep1)) /= Intval (Position (CC)) or else Intval (First_Bit (Rep1)) /= Intval (First_Bit (CC)) or else Intval (Last_Bit (Rep1)) /= Intval (Last_Bit (CC)) then Error_Msg_N ("component clause inconsistent " & "with representation of ancestor", CC); elsif Warn_On_Redundant_Constructs then Error_Msg_N ("?redundant component clause " & "for inherited component!", CC); end if; end; end if; -- Normal case where this is the first component clause we -- have seen for this entity, so set it up properly. else -- Make reference for field in record rep clause and set -- appropriate entity field in the field identifier. Generate_Reference (Comp, Component_Name (CC), Set_Ref => False); Set_Entity (Component_Name (CC), Comp); -- 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&", Component_Name (CC), Rectype); 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 Biased and Warn_On_Biased_Representation then Error_Msg_F ("?component clause forces biased " & "representation", CC); end if; 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; -- If OK component size, check parent type overlap if -- this component might overlap a parent field. if Present (Tagged_Parent) and then Fbit <= Parent_Last_Bit then Pcomp := First_Entity (Tagged_Parent); while Present (Pcomp) loop if (Ekind (Pcomp) = E_Discriminant or else Ekind (Pcomp) = E_Component) and then not Is_Tag (Pcomp) and then Chars (Pcomp) /= Name_uParent then Check_Component_Overlap (Comp, Pcomp); end if; Next_Entity (Pcomp); end loop; 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 procedure OC_Move (From : Natural; To : Natural); -- Move routine for Sort package Sorting is new GNAT.Heap_Sort_G (OC_Move, OC_Lt); ----------- -- OC_Lt -- ----------- function OC_Lt (Op1, Op2 : Natural) return Boolean is begin return OC_Fbit (Op1) < OC_Fbit (Op2); end OC_Lt; ------------- -- OC_Move -- ------------- procedure OC_Move (From : Natural; To : Natural) is begin OC_Fbit (To) := OC_Fbit (From); OC_Lbit (To) := OC_Lbit (From); end OC_Move; -- Start of processing for Overlap_Check 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; Sorting.Sort (OC_Count); 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 -- different 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_In (Clist, N_Full_Type_Declaration, 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 the parent of the component list is the -- record definition, and its parent is the full type -- declaration containing 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; <<Continue_Main_Component_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 appropriate 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 has no component clause Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop exit when No (Component_Clause (Comp)); Next_Component_Or_Discriminant (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. if No (Comp) then Set_RM_Size (Rectype, Hbit + 1); end if; end if; -- Check missing components if Complete_Representation pragma appeared if Present (CR_Pragma) then Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop if No (Component_Clause (Comp)) then Error_Msg_NE ("missing component clause for &", CR_Pragma, Comp); end if; Next_Component_Or_Discriminant (Comp); end loop; -- If no Complete_Representation pragma, warn if missing components elsif Warn_On_Unrepped_Components then declare Num_Repped_Components : Nat := 0; Num_Unrepped_Components : Nat := 0; begin -- First count number of repped and unrepped components Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop if Present (Component_Clause (Comp)) then Num_Repped_Components := Num_Repped_Components + 1; else Num_Unrepped_Components := Num_Unrepped_Components + 1; end if; Next_Component_Or_Discriminant (Comp); end loop; -- We are only interested in the case where there is at least one -- unrepped component, and at least half the components have rep -- clauses. We figure that if less than half have them, then the -- partial rep clause is really intentional. If the component -- type has no underlying type set at this point (as for a generic -- formal type), we don't know enough to give a warning on the -- component. if Num_Unrepped_Components > 0 and then Num_Unrepped_Components < Num_Repped_Components then Comp := First_Component_Or_Discriminant (Rectype); while Present (Comp) loop if No (Component_Clause (Comp)) and then Comes_From_Source (Comp) and then Present (Underlying_Type (Etype (Comp))) and then (Is_Scalar_Type (Underlying_Type (Etype (Comp))) or else Size_Known_At_Compile_Time (Underlying_Type (Etype (Comp)))) and then not Has_Warnings_Off (Rectype) then Error_Msg_Sloc := Sloc (Comp); Error_Msg_NE ("?no component clause given for & declared #", N, Comp); end if; Next_Component_Or_Discriminant (Comp); end loop; end if; end; 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! (RM 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_Node_2 := U_Ent; Error_Msg_NE ("\& must be defined before & (RM 13.1(22))!", Nod, Entity (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 (RM 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 Loc_U_Ent : constant Source_Ptr := Sloc (U_Ent); Ent : Entity_Id := Empty; 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 => Ent := Entity (Nod); -- We need to look at the original node if it is different -- from the node, since we may have rewritten things and -- substituted an identifier representing the rewrite. if Original_Node (Nod) /= Nod then Check_Expr_Constants (Original_Node (Nod)); -- If the node is an object declaration without initial -- value, some code has been expanded, and the expression -- is not constant, even if the constituents might be -- acceptable, as in A'Address + offset. if Ekind (Ent) = E_Variable and then Nkind (Declaration_Node (Ent)) = N_Object_Declaration and then No (Expression (Declaration_Node (Ent))) then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); -- If entity is constant, it may be the result of expanding -- a check. We must verify that its declaration appears -- before the object in question, else we also reject the -- address clause. elsif Ekind (Ent) = E_Constant and then In_Same_Source_Unit (Ent, U_Ent) and then Sloc (Ent) > Loc_U_Ent then Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); end if; return; end if; -- Otherwise look at the identifier and see if it is OK 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 Sloc (Ent) < Loc_U_Ent then return; else Error_Msg_NE ("invalid address clause for initialized object &!", Nod, U_Ent); Error_Msg_Node_2 := U_Ent; Error_Msg_NE ("\& must be defined before & (RM 13.1(22))!", Nod, Ent); 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); if Comes_From_Source (Ent) then Error_Msg_NE ("\reference to variable& not allowed" & " (RM 13.1(22))!", Nod, Ent); else Error_Msg_N ("non-static expression not allowed" & " (RM 13.1(22))!", Nod); end if; end if; when N_Integer_Literal => -- If this is a rewritten unchecked conversion, in a system -- where Address is an integer type, always use the base type -- for a literal value. This is user-friendly and prevents -- order-of-elaboration issues with instances of unchecked -- conversion. if Nkind (Original_Node (Nod)) = N_Function_Call then Set_Etype (Nod, Base_Type (Etype (Nod))); end if; when 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_Short_Circuit | N_Membership_Test => 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 (RM 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& (RM 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; -- Dismiss cases for generic types or types 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)) then return; -- Check case of bit packed array elsif Is_Array_Type (UT) and then Known_Static_Component_Size (UT) and then Is_Bit_Packed_Array (UT) then declare Asiz : Uint; Indx : Node_Id; Ityp : Entity_Id; begin Asiz := Component_Size (UT); Indx := First_Index (UT); loop Ityp := Etype (Indx); -- If non-static bound, then we are not in the business of -- trying to check the length, and indeed an error will be -- issued elsewhere, since sizes of non-static array types -- cannot be set implicitly or explicitly. if not Is_Static_Subtype (Ityp) then return; end if; -- Otherwise accumulate next dimension Asiz := Asiz * (Expr_Value (Type_High_Bound (Ityp)) - Expr_Value (Type_Low_Bound (Ityp)) + Uint_1); Next_Index (Indx); exit when No (Indx); end loop; if Asiz <= Siz then return; else Error_Msg_Uint_1 := Asiz; Error_Msg_NE ("size for& too small, minimum allowed is ^", N, T); Set_Esize (T, Asiz); Set_RM_Size (T, Asiz); end if; end; -- All other composite types are ignored elsif Is_Composite_Type (UT) then return; -- For fixed-point types, don't check minimum if type is not frozen, -- since we don't know all the characteristics of the type that can -- affect the size (e.g. a specified small) till 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 -- Ignore if specified size is correct for the type if Known_Esize (UT) and then Siz = Esize (UT) then return; end if; -- Otherwise get minimum size 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); Set_Esize (T, M); Set_RM_Size (T, M); 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. Normally an access type cannot have a size smaller -- than the size of System.Address. The exception is on VMS, where -- we have short and long addresses, and it is possible for an access -- type to have a short address size (and thus be less than the size -- of System.Address itself). We simply skip the check for VMS, and -- leave it to the back end to do the check. elsif Is_Access_Type (T) then if OpenVMS_On_Target then return 0; else return System_Address_Size; end if; -- 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; -- Note: In the following two tests for LoSet and HiSet, it may -- seem redundant to test for N_Real_Literal here since normally -- one would assume that the test for the value being known at -- compile time includes this case. However, there is a glitch. -- If the real literal comes from folding a non-static expression, -- then we don't consider any non- static expression to be known -- at compile time if we are in configurable run time mode (needed -- in some cases to give a clearer definition of what is and what -- is not accepted). So the test is indeed needed. Without it, we -- would set neither Lo_Set nor Hi_Set and get an infinite loop. 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) and then not (Is_Enumeration_Type (T) and then Has_Non_Standard_Rep (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 accommodated 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_Subprogram -- --------------------------- procedure New_Stream_Subprogram (N : Node_Id; Ent : Entity_Id; Subp : Entity_Id; Nam : TSS_Name_Type) is Loc : constant Source_Ptr := Sloc (N); Sname : constant Name_Id := Make_TSS_Name (Base_Type (Ent), Nam); Subp_Id : Entity_Id; Subp_Decl : Node_Id; F : Entity_Id; Etyp : Entity_Id; Defer_Declaration : constant Boolean := Is_Tagged_Type (Ent) or else Is_Private_Type (Ent); -- For a tagged type, there is a declaration for each stream attribute -- at the freeze point, and we must generate only a completion of this -- declaration. We do the same for private types, because the full view -- might be tagged. Otherwise we generate a declaration at the point of -- the attribute definition clause. 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 Out_P : constant Boolean := (Nam = TSS_Stream_Read); Formals : List_Id; Spec : Node_Id; T_Ref : constant Node_Id := New_Reference_To (Etyp, Loc); begin Subp_Id := Make_Defining_Identifier (Loc, Sname); -- S : access Root_Stream_Type'Class Formals := 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)))); if Nam = TSS_Stream_Input then Spec := Make_Function_Specification (Loc, Defining_Unit_Name => Subp_Id, Parameter_Specifications => Formals, Result_Definition => T_Ref); else -- V : [out] T Append_To (Formals, Make_Parameter_Specification (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, Name_V), Out_Present => Out_P, Parameter_Type => T_Ref)); Spec := Make_Procedure_Specification (Loc, Defining_Unit_Name => Subp_Id, Parameter_Specifications => Formals); end if; return Spec; end Build_Spec; -- Start of processing for New_Stream_Subprogram begin F := First_Formal (Subp); if Ekind (Subp) = E_Procedure then Etyp := Etype (Next_Formal (F)); else Etyp := Etype (Subp); end if; -- Prepare subprogram declaration and insert it as an action on the -- clause node. The visibility for this entity is used to test for -- visibility of the attribute definition clause (in the sense of -- 8.3(23) as amended by AI-195). if not Defer_Declaration then Subp_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Spec); -- For a tagged type, there is always a visible declaration for each -- stream TSS (it is a predefined primitive operation), and the -- completion of this declaration occurs at the freeze point, which is -- not always visible at places where the attribute definition clause is -- visible. So, we create a dummy entity here for the purpose of -- tracking the visibility of the attribute definition clause itself. else Subp_Id := Make_Defining_Identifier (Loc, Chars => New_External_Name (Sname, 'V')); Subp_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Subp_Id, Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc)); end if; Insert_Action (N, Subp_Decl); Set_Entity (N, Subp_Id); Subp_Decl := Make_Subprogram_Renaming_Declaration (Loc, Specification => Build_Spec, Name => New_Reference_To (Subp, Loc)); if Defer_Declaration 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_Subprogram; ------------------------ -- Rep_Item_Too_Early -- ------------------------ function Rep_Item_Too_Early (T : Entity_Id; N : Node_Id) return Boolean is begin -- Cannot apply non-operational rep 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 incomplete 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 incomplete 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. Note that this is not considered a -- serious error, since the effect is simply that we ignore the -- representation clause in this case. -------------- -- Too_Late -- -------------- 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, -- but avoid chaining if we have an overloadable entity, and the pragma -- is one that can apply to multiple overloaded entities. if Is_Overloadable (T) and then Nkind (N) = N_Pragma then declare Pname : constant Name_Id := Pragma_Name (N); begin if Pname = Name_Convention or else Pname = Name_Import or else Pname = Name_Export or else Pname = Name_External or else Pname = Name_Interface then return False; end if; end; end if; 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 -------------- -- Same_Rep -- -------------- 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 of processing for Record_Case begin if Has_Discriminants (T1) then CD1 := First_Discriminant (T1); CD2 := First_Discriminant (T2); -- The number of discriminants may be different if the -- derived type has fewer (constrained by values). The -- invisible discriminants retain the representation of -- the original, so the discrepancy does not per se -- indicate a different representation. while Present (CD1) and then Present (CD2) 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_Address_Clauses -- ------------------------------ procedure Validate_Address_Clauses is begin for J in Address_Clause_Checks.First .. Address_Clause_Checks.Last loop declare ACCR : Address_Clause_Check_Record renames Address_Clause_Checks.Table (J); Expr : Node_Id; X_Alignment : Uint; Y_Alignment : Uint; X_Size : Uint; Y_Size : Uint; begin -- Skip processing of this entry if warning already posted if not Address_Warning_Posted (ACCR.N) then Expr := Original_Node (Expression (ACCR.N)); -- Get alignments X_Alignment := Alignment (ACCR.X); Y_Alignment := Alignment (ACCR.Y); -- Similarly obtain sizes X_Size := Esize (ACCR.X); Y_Size := Esize (ACCR.Y); -- Check for large object overlaying smaller one if Y_Size > Uint_0 and then X_Size > Uint_0 and then X_Size > Y_Size then Error_Msg_NE ("?& overlays smaller object", ACCR.N, ACCR.X); Error_Msg_N ("\?program execution may be erroneous", ACCR.N); Error_Msg_Uint_1 := X_Size; Error_Msg_NE ("\?size of & is ^", ACCR.N, ACCR.X); Error_Msg_Uint_1 := Y_Size; Error_Msg_NE ("\?size of & is ^", ACCR.N, ACCR.Y); -- Check for inadequate alignment, both of the base object -- and of the offset, if any. -- Note: we do not check the alignment if we gave a size -- warning, since it would likely be redundant. elsif Y_Alignment /= Uint_0 and then (Y_Alignment < X_Alignment or else (ACCR.Off and then Nkind (Expr) = N_Attribute_Reference and then Attribute_Name (Expr) = Name_Address and then Has_Compatible_Alignment (ACCR.X, Prefix (Expr)) /= Known_Compatible)) then Error_Msg_NE ("?specified address for& may be inconsistent " & "with alignment", ACCR.N, ACCR.X); Error_Msg_N ("\?program execution may be erroneous (RM 13.3(27))", ACCR.N); Error_Msg_Uint_1 := X_Alignment; Error_Msg_NE ("\?alignment of & is ^", ACCR.N, ACCR.X); Error_Msg_Uint_1 := Y_Alignment; Error_Msg_NE ("\?alignment of & is ^", ACCR.N, ACCR.Y); if Y_Alignment >= X_Alignment then Error_Msg_N ("\?but offset is not multiple of alignment", ACCR.N); end if; end if; end if; end; end loop; end Validate_Address_Clauses; ----------------------------------- -- 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; -- Warn if conversion between two different convention pointers if Is_Access_Type (Target) and then Is_Access_Type (Source) and then Convention (Target) /= Convention (Source) and then Warn_On_Unchecked_Conversion then -- Give warnings for subprogram pointers only on most targets. The -- exception is VMS, where data pointers can have different lengths -- depending on the pointer convention. if Is_Access_Subprogram_Type (Target) or else Is_Access_Subprogram_Type (Source) or else OpenVMS_On_Target then Error_Msg_N ("?conversion between pointers with different conventions!", N); end if; end if; -- Warn if one of the operands is Ada.Calendar.Time. Do not emit a -- warning when compiling GNAT-related sources. if Warn_On_Unchecked_Conversion and then not In_Predefined_Unit (N) and then RTU_Loaded (Ada_Calendar) and then (Chars (Source) = Name_Time or else Chars (Target) = Name_Time) then -- If Ada.Calendar is loaded and the name of one of the operands is -- Time, there is a good chance that this is Ada.Calendar.Time. declare Calendar_Time : constant Entity_Id := Full_View (RTE (RO_CA_Time)); begin pragma Assert (Present (Calendar_Time)); if Source = Calendar_Time or else Target = Calendar_Time then Error_Msg_N ("?representation of 'Time values may change between " & "'G'N'A'T versions", N); end if; end; 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). This is only done -- if the appropriate warning is active. if Warn_On_Unchecked_Conversion then Unchecked_Conversions.Append (New_Val => UC_Entry' (Eloc => Sloc (N), Source => Source, Target => Target)); -- If both sizes are known statically now, then back end annotation -- is not required to do a proper check but if either size is not -- known statically, then we need the annotation. if Known_Static_RM_Size (Source) and then Known_Static_RM_Size (Target) then null; else Back_Annotate_Rep_Info := True; end if; end if; -- If unchecked conversion to access type, and access type is declared -- in the same unit as the unchecked conversion, then set the -- No_Strict_Aliasing flag (no strict aliasing is implicit in this -- situation). if Is_Access_Type (Target) and then In_Same_Source_Unit (Target, N) then Set_No_Strict_Aliasing (Implementation_Base_Type (Target)); end if; -- Generate N_Validate_Unchecked_Conversion node for back end in -- case the back end needs to perform special validation checks. -- Shouldn't this be in Exp_Ch13, since the check only gets done -- if we have full expansion and the back end is called ??? Vnode := Make_Validate_Unchecked_Conversion (Sloc (N)); Set_Source_Type (Vnode, Source); Set_Target_Type (Vnode, Target); -- If the unchecked conversion node is in a list, just insert before it. -- If not we have some strange case, not worth bothering about. if Is_List_Member (N) then 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); Eloc : constant Source_Ptr := T.Eloc; 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) -- Don't do the check if warnings off for either type, note the -- deliberate use of OR here instead of OR ELSE to get the flag -- Warnings_Off_Used set for both types if appropriate. and then not (Has_Warnings_Off (Source) or Has_Warnings_Off (Target)) then Source_Siz := RM_Size (Source); Target_Siz := RM_Size (Target); if Source_Siz /= Target_Siz then Error_Msg ("?types for unchecked conversion have different sizes!", Eloc); 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 ("\size of % is ^, size of % is ^?", Eloc); 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 ("\?^ high order bits of source will be ignored!", Eloc); elsif Is_Unsigned_Type (Source) then Error_Msg ("\?source will be extended with ^ high order " & "zero bits?!", Eloc); else Error_Msg ("\?source will be extended with ^ high order " & "sign bits!", Eloc); end if; elsif Source_Siz < Target_Siz then if Is_Discrete_Type (Target) then if Bytes_Big_Endian then Error_Msg ("\?target value will include ^ undefined " & "low order bits!", Eloc); else Error_Msg ("\?target value will include ^ undefined " & "high order bits!", Eloc); end if; else Error_Msg ("\?^ trailing bits of target value will be " & "undefined!", Eloc); end if; else pragma Assert (Source_Siz > Target_Siz); Error_Msg ("\?^ trailing bits of source will be ignored!", Eloc); end if; end if; 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) -- Suppress warning if warnings suppressed on either -- type or either designated type. Note the use of -- OR here instead of OR ELSE. That is intentional, -- we would like to set flag Warnings_Off_Used in -- all types for which warnings are suppressed. and then not (Has_Warnings_Off (D_Source) or Has_Warnings_Off (D_Target) or Has_Warnings_Off (Source) or Has_Warnings_Off (Target)) then Error_Msg_Uint_1 := Target_Align; Error_Msg_Uint_2 := Source_Align; Error_Msg_Node_1 := D_Target; Error_Msg_Node_2 := D_Source; Error_Msg ("?alignment of & (^) is stricter than " & "alignment of & (^)!", Eloc); Error_Msg ("\?resulting access value may have invalid " & "alignment!", Eloc); end if; end; end if; end; end if; end; end loop; end Validate_Unchecked_Conversions; end Sem_Ch13;
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