------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- P A R . C H 2 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2018, 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 Ch2 is -- Local functions, used only in this chapter procedure Scan_Pragma_Argument_Association (Identifier_Seen : in out Boolean; Association : out Node_Id; Reserved_Words_OK : Boolean := False); -- Scans out a pragma argument association. Identifier_Seen is True on -- entry if a previous association had an identifier, and gets set True -- if the scanned association has an identifier (this is used to check the -- rule that no associations without identifiers can follow an association -- which has an identifier). The result is returned in Association. Flag -- For_Pragma_Restrictions should be set when arguments are being parsed -- for pragma Restrictions. -- -- Note: We allow attribute forms Pre'Class, Post'Class, Invariant'Class, -- Type_Invariant'Class in place of a pragma argument identifier. Rather -- than handle this case specially, we replace such references with -- one of the special internal identifiers _Pre, _Post, _Invariant, or -- _Type_Invariant, and this procedure is where this replacement occurs. --------------------- -- 2.3 Identifier -- --------------------- -- IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT} -- LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT -- An IDENTIFIER shall not be a reserved word -- Error recovery: can raise Error_Resync (cannot return Error) function P_Identifier (C : Id_Check := None) return Node_Id is Ident_Node : Node_Id; begin -- All set if we do indeed have an identifier -- Code duplication, see Par_Ch3.P_Defining_Identifier??? if Token = Tok_Identifier then Check_Future_Keyword; Ident_Node := Token_Node; Scan; -- past Identifier return Ident_Node; -- If we have a reserved identifier, manufacture an identifier with -- a corresponding name after posting an appropriate error message elsif Is_Reserved_Identifier (C) then Scan_Reserved_Identifier (Force_Msg => False); Ident_Node := Token_Node; Scan; -- past the node return Ident_Node; -- Otherwise we have junk that cannot be interpreted as an identifier else T_Identifier; -- to give message raise Error_Resync; end if; end P_Identifier; -------------------------- -- 2.3 Letter Or Digit -- -------------------------- -- Parsed by P_Identifier (2.3) -------------------------- -- 2.4 Numeric Literal -- -------------------------- -- NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL -- Numeric literal is returned by the scanner as either -- Tok_Integer_Literal or Tok_Real_Literal ---------------------------- -- 2.4.1 Decimal Literal -- ---------------------------- -- DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT] -- Handled by scanner as part of numeric literal handing (see 2.4) -------------------- -- 2.4.1 Numeral -- -------------------- -- NUMERAL ::= DIGIT {[UNDERLINE] DIGIT} -- Handled by scanner as part of numeric literal handling (see 2.4) --------------------- -- 2.4.1 Exponent -- --------------------- -- EXPONENT ::= E [+] NUMERAL | E - NUMERAL -- Handled by scanner as part of numeric literal handling (see 2.4) -------------------------- -- 2.4.2 Based Literal -- -------------------------- -- BASED_LITERAL ::= -- BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT] -- Handled by scanner as part of numeric literal handling (see 2.4) ----------------- -- 2.4.2 Base -- ----------------- -- BASE ::= NUMERAL -- Handled by scanner as part of numeric literal handling (see 2.4) -------------------------- -- 2.4.2 Based Numeral -- -------------------------- -- BASED_NUMERAL ::= -- EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT} -- Handled by scanner as part of numeric literal handling (see 2.4) --------------------------- -- 2.4.2 Extended Digit -- --------------------------- -- EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F -- Handled by scanner as part of numeric literal handling (see 2.4) ---------------------------- -- 2.5 Character Literal -- ---------------------------- -- CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER ' -- Handled by the scanner and returned as Tok_Char_Literal ------------------------- -- 2.6 String Literal -- ------------------------- -- STRING LITERAL ::= "{STRING_ELEMENT}" -- Handled by the scanner and returned as Tok_String_Literal -- or if the string looks like an operator as Tok_Operator_Symbol. ------------------------- -- 2.6 String Element -- ------------------------- -- STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER -- A STRING_ELEMENT is either a pair of quotation marks ("), -- or a single GRAPHIC_CHARACTER other than a quotation mark. -- Handled by scanner as part of string literal handling (see 2.4) ------------------ -- 2.7 Comment -- ------------------ -- A COMMENT starts with two adjacent hyphens and extends up to the -- end of the line. A COMMENT may appear on any line of a program. -- Handled by the scanner which simply skips past encountered comments ----------------- -- 2.8 Pragma -- ----------------- -- PRAGMA ::= pragma IDENTIFIER -- [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})]; -- The caller has checked that the initial token is PRAGMA -- Error recovery: cannot raise Error_Resync -- One special piece of processing is needed in this routine. As described -- in the section on "Handling semicolon used in place of IS" in module -- Parse, the parser detects the case of missing subprogram bodies to -- allow recovery from this syntactic error. Pragma INTERFACE (and, for -- Ada 95, pragma IMPORT) can appear in place of the body. The parser must -- recognize the use of these two pragmas in this context, otherwise it -- will think there are missing bodies, and try to change ; to IS, when -- in fact the bodies ARE present, supplied by these pragmas. function P_Pragma (Skipping : Boolean := False) return Node_Id is procedure Skip_Pragma_Semicolon; -- Skip past semicolon at end of pragma --------------------------- -- Skip_Pragma_Semicolon -- --------------------------- procedure Skip_Pragma_Semicolon is begin -- If skipping the pragma, ignore a missing semicolon if Token /= Tok_Semicolon and then Skipping then null; -- Otherwise demand a semicolon else T_Semicolon; end if; end Skip_Pragma_Semicolon; -- Local variables Interface_Check_Required : Boolean := False; -- Set True if check of pragma INTERFACE is required Import_Check_Required : Boolean := False; -- Set True if check of pragma IMPORT is required Arg_Count : Nat := 0; -- Number of argument associations processed Identifier_Seen : Boolean := False; -- Set True if an identifier is encountered for a pragma argument. Used -- to check that there are no more arguments without identifiers. Assoc_Node : Node_Id; Ident_Node : Node_Id; Prag_Name : Name_Id; Prag_Node : Node_Id; Result : Node_Id; Semicolon_Loc : Source_Ptr; -- Start of processing for P_Pragma begin Inside_Pragma := True; Prag_Node := New_Node (N_Pragma, Token_Ptr); Scan; -- past PRAGMA Prag_Name := Token_Name; if Style_Check then Style.Check_Pragma_Name; end if; -- Ada 2005 (AI-284): INTERFACE is a new reserved word but it is -- allowed as a pragma name. if Is_Reserved_Keyword (Token) then Prag_Name := Keyword_Name (Token); Ident_Node := Make_Identifier (Token_Ptr, Prag_Name); Scan; -- past the keyword else Ident_Node := P_Identifier; end if; Set_Pragma_Identifier (Prag_Node, Ident_Node); -- See if special INTERFACE/IMPORT check is required if SIS_Entry_Active then Interface_Check_Required := (Prag_Name = Name_Interface); Import_Check_Required := (Prag_Name = Name_Import); else Interface_Check_Required := False; Import_Check_Required := False; end if; -- Set global to indicate if we are within a Depends pragma if Chars (Ident_Node) = Name_Depends or else Chars (Ident_Node) = Name_Refined_Depends then Inside_Depends := True; end if; -- Scan arguments. We assume that arguments are present if there is -- a left paren, or if a semicolon is missing and there is another -- token on the same line as the pragma name. if Token = Tok_Left_Paren or else (Token /= Tok_Semicolon and then not Token_Is_At_Start_Of_Line) then Set_Pragma_Argument_Associations (Prag_Node, New_List); T_Left_Paren; loop Arg_Count := Arg_Count + 1; Scan_Pragma_Argument_Association (Identifier_Seen => Identifier_Seen, Association => Assoc_Node, Reserved_Words_OK => Nam_In (Prag_Name, Name_Restriction_Warnings, Name_Restrictions)); if Arg_Count = 2 and then (Interface_Check_Required or else Import_Check_Required) then -- Here is where we cancel the SIS active status if this pragma -- supplies a body for the currently active subprogram spec. if Nkind (Expression (Assoc_Node)) in N_Direct_Name and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl) then SIS_Entry_Active := False; end if; end if; Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node)); exit when Token /= Tok_Comma; Scan; -- past comma end loop; -- If we have := for pragma Debug, it is worth special casing the -- error message (it is easy to think of pragma Debug as taking a -- statement, and an assignment statement is the most likely -- candidate for this error) if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then Error_Msg_SC ("argument for pragma Debug must be procedure call"); Resync_To_Semicolon; -- Normal case, we expect a right paren here else T_Right_Paren; end if; end if; Semicolon_Loc := Token_Ptr; -- Cancel indication of being within a pragma or in particular a Depends -- pragma. Inside_Depends := False; Inside_Pragma := False; -- Now we have two tasks left, we need to scan out the semicolon -- following the pragma, and we have to call Par.Prag to process -- the pragma. Normally we do them in this order, however, there -- is one exception namely pragma Style_Checks where we like to -- skip the semicolon after processing the pragma, since that way -- the style checks for the scanning of the semicolon follow the -- settings of the pragma. -- You might think we could just unconditionally do things in -- the opposite order, but there are other pragmas, notably the -- case of pragma Source_File_Name, which assume the semicolon -- is already scanned out. if Prag_Name = Name_Style_Checks then Result := Par.Prag (Prag_Node, Semicolon_Loc); Skip_Pragma_Semicolon; return Result; else Skip_Pragma_Semicolon; return Par.Prag (Prag_Node, Semicolon_Loc); end if; exception when Error_Resync => Resync_Past_Semicolon; Inside_Depends := False; Inside_Pragma := False; return Error; end P_Pragma; -- This routine is called if a pragma is encountered in an inappropriate -- position, the pragma is scanned out and control returns to continue. -- The caller has checked that the initial token is pragma -- Error recovery: cannot raise Error_Resync procedure P_Pragmas_Misplaced is begin while Token = Tok_Pragma loop Error_Msg_SC ("pragma not allowed here"); Discard_Junk_Node (P_Pragma (Skipping => True)); end loop; end P_Pragmas_Misplaced; -- This function is called to scan out an optional sequence of pragmas. -- If no pragmas are found, then No_List is returned. -- Error recovery: Cannot raise Error_Resync function P_Pragmas_Opt return List_Id is L : List_Id; begin if Token = Tok_Pragma then L := New_List; P_Pragmas_Opt (L); return L; else return No_List; end if; end P_Pragmas_Opt; -- This procedure is called to scan out an optional sequence of pragmas. -- Any pragmas found are appended to the list provided as an argument. -- Error recovery: Cannot raise Error_Resync procedure P_Pragmas_Opt (List : List_Id) is P : Node_Id; begin while Token = Tok_Pragma loop P := P_Pragma; if Nkind (P) /= N_Error and then Nam_In (Pragma_Name_Unmapped (P), Name_Assert, Name_Debug) then Error_Msg_Name_1 := Pragma_Name_Unmapped (P); Error_Msg_N ("pragma% must be in declaration/statement context", P); else Append (P, List); end if; end loop; end P_Pragmas_Opt; -------------------------------------- -- 2.8 Pragma_Argument Association -- -------------------------------------- -- PRAGMA_ARGUMENT_ASSOCIATION ::= -- [pragma_argument_IDENTIFIER =>] NAME -- | [pragma_argument_IDENTIFIER =>] EXPRESSION -- In Ada 2012, there are two more possibilities: -- PRAGMA_ARGUMENT_ASSOCIATION ::= -- [pragma_argument_ASPECT_MARK =>] NAME -- | [pragma_argument_ASPECT_MARK =>] EXPRESSION -- where the interesting allowed cases (which do not fit the syntax of the -- first alternative above) are -- ASPECT_MARK ::= -- Pre'Class | Post'Class | Invariant'Class | Type_Invariant'Class -- We allow this special usage in all Ada modes, but it would be a pain to -- allow these aspects to pervade the pragma syntax, and the representation -- of pragma nodes internally. So what we do is to replace these -- ASPECT_MARK forms with identifiers whose name is one of the special -- internal names _Pre, _Post, _Invariant, or _Type_Invariant. -- Error recovery: cannot raise Error_Resync procedure Scan_Pragma_Argument_Association (Identifier_Seen : in out Boolean; Association : out Node_Id; Reserved_Words_OK : Boolean := False) is function P_Expression_Or_Reserved_Word return Node_Id; -- Parse an expression or, if the token is one of the following reserved -- words, construct an identifier with proper Chars field. -- Access -- Delta -- Digits -- Mod -- Range ----------------------------------- -- P_Expression_Or_Reserved_Word -- ----------------------------------- function P_Expression_Or_Reserved_Word return Node_Id is Word : Node_Id; Word_Id : Name_Id; begin Word_Id := No_Name; if Token = Tok_Access then Word_Id := Name_Access; Scan; -- past ACCESS elsif Token = Tok_Delta then Word_Id := Name_Delta; Scan; -- past DELTA elsif Token = Tok_Digits then Word_Id := Name_Digits; Scan; -- past DIGITS elsif Token = Tok_Mod then Word_Id := Name_Mod; Scan; -- past MOD elsif Token = Tok_Range then Word_Id := Name_Range; Scan; -- post RANGE end if; if Word_Id = No_Name then return P_Expression; else Word := New_Node (N_Identifier, Token_Ptr); Set_Chars (Word, Word_Id); return Word; end if; end P_Expression_Or_Reserved_Word; -- Local variables Expression_Node : Node_Id; Identifier_Node : Node_Id; Identifier_OK : Boolean; Scan_State : Saved_Scan_State; -- Start of processing for Scan_Pragma_Argument_Association begin Association := New_Node (N_Pragma_Argument_Association, Token_Ptr); Set_Chars (Association, No_Name); Identifier_OK := False; -- Argument starts with identifier if Token = Tok_Identifier then Identifier_Node := Token_Node; Save_Scan_State (Scan_State); -- at Identifier Scan; -- past Identifier if Token = Tok_Arrow then Scan; -- past arrow Identifier_OK := True; -- Case of one of the special aspect forms elsif Token = Tok_Apostrophe then Scan; -- past apostrophe -- We have apostrophe, so check for identifier'Class if Token /= Tok_Identifier or else Token_Name /= Name_Class then null; -- We have identifier'Class, check for arrow else Scan; -- Past Class if Token /= Tok_Arrow then null; -- Here we have scanned identifier'Class => else Identifier_OK := True; Scan; -- past arrow case Chars (Identifier_Node) is when Name_Pre => Set_Chars (Identifier_Node, Name_uPre); when Name_Post => Set_Chars (Identifier_Node, Name_uPost); when Name_Type_Invariant => Set_Chars (Identifier_Node, Name_uType_Invariant); when Name_Invariant => Set_Chars (Identifier_Node, Name_uInvariant); -- If it is X'Class => for some invalid X, we will give -- an error, and forget that 'Class was present, which -- will give better error recovery. We could do a spell -- check here, but it seems too much work. when others => Error_Msg_SC ("invalid aspect id for pragma"); end case; end if; end if; end if; -- Identifier was present if Identifier_OK then Set_Chars (Association, Chars (Identifier_Node)); Identifier_Seen := True; -- Identifier not present after all else Restore_Scan_State (Scan_State); -- to Identifier end if; end if; -- Diagnose error of "positional" argument for pragma appearing after -- a "named" argument (quotes here are because that's not quite accurate -- Ada RM terminology). -- Since older GNAT versions did not generate this error, disable this -- message in Relaxed_RM_Semantics mode to help legacy code using e.g. -- codepeer. if Identifier_Seen and not Identifier_OK and not Relaxed_RM_Semantics then Error_Msg_SC ("|pragma argument identifier required here"); Error_Msg_SC ("\since previous argument had identifier (RM 2.8(4))"); end if; if Identifier_OK then -- Certain pragmas such as Restriction_Warnings and Restrictions -- allow reserved words to appear as expressions when checking for -- prohibited uses of attributes. if Reserved_Words_OK and then Chars (Identifier_Node) = Name_No_Use_Of_Attribute then Expression_Node := P_Expression_Or_Reserved_Word; else Expression_Node := P_Expression; end if; else Expression_Node := P_Expression_If_OK; end if; Set_Expression (Association, Expression_Node); end Scan_Pragma_Argument_Association; end Ch2;