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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- P A R . C H 1 3 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2012, 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. -- -- -- ------------------------------------------------------------------------------ pragma Style_Checks (All_Checks); -- Turn off subprogram body ordering check. Subprograms are in order -- by RM section rather than alphabetical separate (Par) package body Ch13 is -- Local functions, used only in this chapter function P_Component_Clause return Node_Id; function P_Mod_Clause return Node_Id; ----------------------------------- -- Aspect_Specifications_Present -- ----------------------------------- function Aspect_Specifications_Present (Strict : Boolean := Ada_Version < Ada_2012) return Boolean is Scan_State : Saved_Scan_State; Result : Boolean; begin -- Definitely must have WITH to consider aspect specs to be present -- Note that this means that if we have a semicolon, we immediately -- return False. There is a case in which this is not optimal, namely -- something like -- type R is new Integer; -- with bla bla; -- where the semicolon is redundant, but scanning forward for it would -- be too expensive. Instead we pick up the aspect specifications later -- as a bogus declaration, and diagnose the semicolon at that point. if Token /= Tok_With then return False; end if; -- Have a WITH, see if it looks like an aspect specification Save_Scan_State (Scan_State); Scan; -- past WITH -- If no identifier, then consider that we definitely do not have an -- aspect specification. if Token /= Tok_Identifier then Result := False; -- This is where we pay attention to the Strict mode. Normally when we -- are in Ada 2012 mode, Strict is False, and we consider that we have -- an aspect specification if the identifier is an aspect name (even if -- not followed by =>) or the identifier is not an aspect name but is -- followed by =>. P_Aspect_Specifications will generate messages if the -- aspect specification is ill-formed. elsif not Strict then if Get_Aspect_Id (Token_Name) /= No_Aspect then Result := True; else Scan; -- past identifier Result := Token = Tok_Arrow; end if; -- If earlier than Ada 2012, check for valid aspect identifier (possibly -- completed with 'CLASS) followed by an arrow, and consider that this -- is still an aspect specification so we give an appropriate message. else if Get_Aspect_Id (Token_Name) = No_Aspect then Result := False; else Scan; -- past aspect name Result := False; if Token = Tok_Arrow then Result := True; elsif Token = Tok_Apostrophe then Scan; -- past apostrophe if Token = Tok_Identifier and then Token_Name = Name_Class then Scan; -- past CLASS if Token = Tok_Arrow then Result := True; end if; end if; end if; if Result then Restore_Scan_State (Scan_State); Error_Msg_SC ("|aspect specification is an Ada 2012 feature"); Error_Msg_SC ("\|unit must be compiled with -gnat2012 switch"); return True; end if; end if; end if; Restore_Scan_State (Scan_State); return Result; end Aspect_Specifications_Present; -------------------------------------------- -- 13.1 Representation Clause (also I.7) -- -------------------------------------------- -- REPRESENTATION_CLAUSE ::= -- ATTRIBUTE_DEFINITION_CLAUSE -- | ENUMERATION_REPRESENTATION_CLAUSE -- | RECORD_REPRESENTATION_CLAUSE -- | AT_CLAUSE -- ATTRIBUTE_DEFINITION_CLAUSE ::= -- for LOCAL_NAME'ATTRIBUTE_DESIGNATOR use EXPRESSION; -- | for LOCAL_NAME'ATTRIBUTE_DESIGNATOR use NAME; -- Note: in Ada 83, the expression must be a simple expression -- AT_CLAUSE ::= for DIRECT_NAME use at EXPRESSION; -- Note: in Ada 83, the expression must be a simple expression -- ENUMERATION_REPRESENTATION_CLAUSE ::= -- for first_subtype_LOCAL_NAME use ENUMERATION_AGGREGATE; -- ENUMERATION_AGGREGATE ::= ARRAY_AGGREGATE -- RECORD_REPRESENTATION_CLAUSE ::= -- for first_subtype_LOCAL_NAME use -- record [MOD_CLAUSE] -- {COMPONENT_CLAUSE} -- end record; -- Note: for now we allow only a direct name as the local name in the -- above constructs. This probably needs changing later on ??? -- The caller has checked that the initial token is FOR -- Error recovery: cannot raise Error_Resync, if an error occurs, -- the scan is repositioned past the next semicolon. function P_Representation_Clause return Node_Id is For_Loc : Source_Ptr; Name_Node : Node_Id; Prefix_Node : Node_Id; Attr_Name : Name_Id; Identifier_Node : Node_Id; Rep_Clause_Node : Node_Id; Expr_Node : Node_Id; Record_Items : List_Id; begin For_Loc := Token_Ptr; Scan; -- past FOR -- Note that the name in a representation clause is always a simple -- name, even in the attribute case, see AI-300 which made this so! Identifier_Node := P_Identifier (C_Use); -- Check case of qualified name to give good error message if Token = Tok_Dot then Error_Msg_SC ("representation clause requires simple name!"); loop exit when Token /= Tok_Dot; Scan; -- past dot Discard_Junk_Node (P_Identifier); end loop; end if; -- Attribute Definition Clause if Token = Tok_Apostrophe then -- Allow local names of the form a'b'.... This enables -- us to parse class-wide streams attributes correctly. Name_Node := Identifier_Node; while Token = Tok_Apostrophe loop Scan; -- past apostrophe Identifier_Node := Token_Node; Attr_Name := No_Name; if Token = Tok_Identifier then Attr_Name := Token_Name; if not Is_Attribute_Name (Attr_Name) then Signal_Bad_Attribute; end if; if Style_Check then Style.Check_Attribute_Name (False); end if; -- Here for case of attribute designator is not an identifier else if Token = Tok_Delta then Attr_Name := Name_Delta; elsif Token = Tok_Digits then Attr_Name := Name_Digits; elsif Token = Tok_Access then Attr_Name := Name_Access; else Error_Msg_AP ("attribute designator expected"); raise Error_Resync; end if; if Style_Check then Style.Check_Attribute_Name (True); end if; end if; -- We come here with an OK attribute scanned, and the -- corresponding Attribute identifier node stored in Ident_Node. Prefix_Node := Name_Node; Name_Node := New_Node (N_Attribute_Reference, Prev_Token_Ptr); Set_Prefix (Name_Node, Prefix_Node); Set_Attribute_Name (Name_Node, Attr_Name); Scan; end loop; Rep_Clause_Node := New_Node (N_Attribute_Definition_Clause, For_Loc); Set_Name (Rep_Clause_Node, Prefix_Node); Set_Chars (Rep_Clause_Node, Attr_Name); T_Use; Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_Expression (Rep_Clause_Node, Expr_Node); else TF_Use; Rep_Clause_Node := Empty; -- AT follows USE (At Clause) if Token = Tok_At then Scan; -- past AT Rep_Clause_Node := New_Node (N_At_Clause, For_Loc); Set_Identifier (Rep_Clause_Node, Identifier_Node); Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_Expression (Rep_Clause_Node, Expr_Node); -- RECORD follows USE (Record Representation Clause) elsif Token = Tok_Record then Record_Items := P_Pragmas_Opt; Rep_Clause_Node := New_Node (N_Record_Representation_Clause, For_Loc); Set_Identifier (Rep_Clause_Node, Identifier_Node); Push_Scope_Stack; Scope.Table (Scope.Last).Etyp := E_Record; Scope.Table (Scope.Last).Ecol := Start_Column; Scope.Table (Scope.Last).Sloc := Token_Ptr; Scan; -- past RECORD Record_Items := P_Pragmas_Opt; -- Possible Mod Clause if Token = Tok_At then Set_Mod_Clause (Rep_Clause_Node, P_Mod_Clause); Set_Pragmas_Before (Mod_Clause (Rep_Clause_Node), Record_Items); Record_Items := P_Pragmas_Opt; end if; if No (Record_Items) then Record_Items := New_List; end if; Set_Component_Clauses (Rep_Clause_Node, Record_Items); -- Loop through component clauses loop if Token not in Token_Class_Name then exit when Check_End; end if; Append (P_Component_Clause, Record_Items); P_Pragmas_Opt (Record_Items); end loop; -- Left paren follows USE (Enumeration Representation Clause) elsif Token = Tok_Left_Paren then Rep_Clause_Node := New_Node (N_Enumeration_Representation_Clause, For_Loc); Set_Identifier (Rep_Clause_Node, Identifier_Node); Set_Array_Aggregate (Rep_Clause_Node, P_Aggregate); -- Some other token follows FOR (invalid representation clause) else Error_Msg_SC ("invalid representation clause"); raise Error_Resync; end if; end if; TF_Semicolon; return Rep_Clause_Node; exception when Error_Resync => Resync_Past_Semicolon; return Error; end P_Representation_Clause; ---------------------- -- 13.1 Local Name -- ---------------------- -- Local name is always parsed by its parent. In the case of its use in -- pragmas, the check for a local name is handled in Par.Prag and allows -- all the possible forms of local name. For the uses in chapter 13, we -- currently only allow a direct name, but this should probably change??? --------------------------- -- 13.1 At Clause (I.7) -- --------------------------- -- Parsed by P_Representation_Clause (13.1) --------------------------------------- -- 13.3 Attribute Definition Clause -- --------------------------------------- -- Parsed by P_Representation_Clause (13.1) -------------------------------- -- 13.1 Aspect Specification -- -------------------------------- -- ASPECT_SPECIFICATION ::= -- with ASPECT_MARK [=> ASPECT_DEFINITION] {, -- ASPECT_MARK [=> ASPECT_DEFINITION] } -- ASPECT_MARK ::= aspect_IDENTIFIER['Class] -- ASPECT_DEFINITION ::= NAME | EXPRESSION -- Error recovery: cannot raise Error_Resync procedure P_Aspect_Specifications (Decl : Node_Id; Semicolon : Boolean := True) is Aspects : List_Id; Aspect : Node_Id; A_Id : Aspect_Id; OK : Boolean; Ptr : Source_Ptr; begin -- Check if aspect specification present if not Aspect_Specifications_Present then if Semicolon then TF_Semicolon; end if; return; end if; -- Aspect Specification is present Ptr := Token_Ptr; Scan; -- past WITH -- Here we have an aspect specification to scan, note that we don't -- set the flag till later, because it may turn out that we have no -- valid aspects in the list. Aspects := Empty_List; loop OK := True; if Token /= Tok_Identifier then Error_Msg_SC ("aspect identifier expected"); if Semicolon then Resync_Past_Semicolon; end if; return; end if; -- We have an identifier (which should be an aspect identifier) A_Id := Get_Aspect_Id (Token_Name); Aspect := Make_Aspect_Specification (Token_Ptr, Identifier => Token_Node); -- No valid aspect identifier present if A_Id = No_Aspect then Error_Msg_SC ("aspect identifier expected"); -- Check bad spelling for J in Aspect_Id loop if Is_Bad_Spelling_Of (Token_Name, Aspect_Names (J)) then Error_Msg_Name_1 := Aspect_Names (J); Error_Msg_SC -- CODEFIX ("\possible misspelling of%"); exit; end if; end loop; Scan; -- past incorrect identifier if Token = Tok_Apostrophe then Scan; -- past ' Scan; -- past presumably CLASS end if; if Token = Tok_Arrow then Scan; -- Past arrow Set_Expression (Aspect, P_Expression); OK := False; elsif Token = Tok_Comma then OK := False; else if Semicolon then Resync_Past_Semicolon; end if; return; end if; -- OK aspect scanned else Scan; -- past identifier -- Check for 'Class present if Token = Tok_Apostrophe then if not Class_Aspect_OK (A_Id) then Error_Msg_Node_1 := Identifier (Aspect); Error_Msg_SC ("aspect& does not permit attribute here"); Scan; -- past apostrophe Scan; -- past presumed CLASS OK := False; else Scan; -- past apostrophe if Token /= Tok_Identifier or else Token_Name /= Name_Class then Error_Msg_SC ("Class attribute expected here"); OK := False; if Token = Tok_Identifier then Scan; -- past identifier not CLASS end if; else Scan; -- past CLASS Set_Class_Present (Aspect); end if; end if; end if; -- Test case of missing aspect definition if Token = Tok_Comma or else Token = Tok_Semicolon then if Aspect_Argument (A_Id) /= Optional then Error_Msg_Node_1 := Identifier (Aspect); Error_Msg_AP ("aspect& requires an aspect definition"); OK := False; end if; elsif not Semicolon and then Token /= Tok_Arrow then if Aspect_Argument (A_Id) /= Optional then -- The name or expression may be there, but the arrow is -- missing. Skip to the end of the declaration. T_Arrow; Resync_To_Semicolon; end if; -- Here we have an aspect definition else if Token = Tok_Arrow then Scan; -- past arrow else T_Arrow; OK := False; end if; if Aspect_Argument (A_Id) = Name then Set_Expression (Aspect, P_Name); else Set_Expression (Aspect, P_Expression); end if; end if; -- If OK clause scanned, add it to the list if OK then Append (Aspect, Aspects); end if; if Token = Tok_Comma then Scan; -- past comma goto Continue; -- Recognize the case where a comma is missing between two -- aspects, issue an error and proceed with next aspect. elsif Token = Tok_Identifier and then Get_Aspect_Id (Token_Name) /= No_Aspect then declare Scan_State : Saved_Scan_State; begin Save_Scan_State (Scan_State); Scan; -- past identifier if Token = Tok_Arrow then Restore_Scan_State (Scan_State); Error_Msg_AP -- CODEFIX ("|missing "","""); goto Continue; else Restore_Scan_State (Scan_State); end if; end; -- Recognize the case where a semicolon was mistyped for a comma -- between two aspects, issue an error and proceed with next -- aspect. elsif Token = Tok_Semicolon then declare Scan_State : Saved_Scan_State; begin Save_Scan_State (Scan_State); Scan; -- past semicolon if Token = Tok_Identifier and then Get_Aspect_Id (Token_Name) /= No_Aspect then Scan; -- past identifier if Token = Tok_Arrow then Restore_Scan_State (Scan_State); Error_Msg_SC -- CODEFIX ("|"";"" should be "","""); Scan; -- past semicolon goto Continue; else Restore_Scan_State (Scan_State); end if; else Restore_Scan_State (Scan_State); end if; end; end if; -- Must be terminator character if Semicolon then T_Semicolon; end if; exit; <<Continue>> null; end if; end loop; -- Here if aspects present if Is_Non_Empty_List (Aspects) then -- If Decl is Empty, we just ignore the aspects (the caller in this -- case has always issued an appropriate error message). if Decl = Empty then null; -- If Decl is Error, we ignore the aspects, and issue a message elsif Decl = Error then Error_Msg ("aspect specifications not allowed here", Ptr); -- Here aspects are allowed, and we store them else Set_Parent (Aspects, Decl); Set_Aspect_Specifications (Decl, Aspects); end if; end if; end P_Aspect_Specifications; --------------------------------------------- -- 13.4 Enumeration Representation Clause -- --------------------------------------------- -- Parsed by P_Representation_Clause (13.1) --------------------------------- -- 13.4 Enumeration Aggregate -- --------------------------------- -- Parsed by P_Representation_Clause (13.1) ------------------------------------------ -- 13.5.1 Record Representation Clause -- ------------------------------------------ -- Parsed by P_Representation_Clause (13.1) ------------------------------ -- 13.5.1 Mod Clause (I.8) -- ------------------------------ -- MOD_CLAUSE ::= at mod static_EXPRESSION; -- Note: in Ada 83, the expression must be a simple expression -- The caller has checked that the initial Token is AT -- Error recovery: cannot raise Error_Resync -- Note: the caller is responsible for setting the Pragmas_Before field function P_Mod_Clause return Node_Id is Mod_Node : Node_Id; Expr_Node : Node_Id; begin Mod_Node := New_Node (N_Mod_Clause, Token_Ptr); Scan; -- past AT T_Mod; Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_Expression (Mod_Node, Expr_Node); TF_Semicolon; return Mod_Node; end P_Mod_Clause; ------------------------------ -- 13.5.1 Component Clause -- ------------------------------ -- COMPONENT_CLAUSE ::= -- COMPONENT_CLAUSE_COMPONENT_NAME at POSITION -- range FIRST_BIT .. LAST_BIT; -- COMPONENT_CLAUSE_COMPONENT_NAME ::= -- component_DIRECT_NAME -- | component_DIRECT_NAME'ATTRIBUTE_DESIGNATOR -- | FIRST_SUBTYPE_DIRECT_NAME'ATTRIBUTE_DESIGNATOR -- POSITION ::= static_EXPRESSION -- Note: in Ada 83, the expression must be a simple expression -- FIRST_BIT ::= static_SIMPLE_EXPRESSION -- LAST_BIT ::= static_SIMPLE_EXPRESSION -- Note: the AARM V2.0 grammar has an error at this point, it uses -- EXPRESSION instead of SIMPLE_EXPRESSION for FIRST_BIT and LAST_BIT -- Error recovery: cannot raise Error_Resync function P_Component_Clause return Node_Id is Component_Node : Node_Id; Comp_Name : Node_Id; Expr_Node : Node_Id; begin Component_Node := New_Node (N_Component_Clause, Token_Ptr); Comp_Name := P_Name; if Nkind (Comp_Name) = N_Identifier or else Nkind (Comp_Name) = N_Attribute_Reference then Set_Component_Name (Component_Node, Comp_Name); else Error_Msg_N ("component name must be direct name or attribute", Comp_Name); Set_Component_Name (Component_Node, Error); end if; Set_Sloc (Component_Node, Token_Ptr); T_At; Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_Position (Component_Node, Expr_Node); T_Range; Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_First_Bit (Component_Node, Expr_Node); T_Dot_Dot; Expr_Node := P_Expression_No_Right_Paren; Check_Simple_Expression_In_Ada_83 (Expr_Node); Set_Last_Bit (Component_Node, Expr_Node); TF_Semicolon; return Component_Node; end P_Component_Clause; ---------------------- -- 13.5.1 Position -- ---------------------- -- Parsed by P_Component_Clause (13.5.1) ----------------------- -- 13.5.1 First Bit -- ----------------------- -- Parsed by P_Component_Clause (13.5.1) ---------------------- -- 13.5.1 Last Bit -- ---------------------- -- Parsed by P_Component_Clause (13.5.1) -------------------------- -- 13.8 Code Statement -- -------------------------- -- CODE_STATEMENT ::= QUALIFIED_EXPRESSION -- On entry the caller has scanned the SUBTYPE_MARK (passed in as the -- single argument, and the scan points to the apostrophe. -- Error recovery: can raise Error_Resync function P_Code_Statement (Subtype_Mark : Node_Id) return Node_Id is Node1 : Node_Id; begin Scan; -- past apostrophe -- If left paren, then we have a possible code statement if Token = Tok_Left_Paren then Node1 := New_Node (N_Code_Statement, Sloc (Subtype_Mark)); Set_Expression (Node1, P_Qualified_Expression (Subtype_Mark)); TF_Semicolon; return Node1; -- Otherwise we have an illegal range attribute. Note that P_Name -- ensures that Token = Tok_Range is the only possibility left here. else -- Token = Tok_Range Error_Msg_SC ("RANGE attribute illegal here!"); raise Error_Resync; end if; end P_Code_Statement; end Ch13;