Geek Gadgets 1

home *** CD-ROM | disk | FTP | other *** search

/ Geek Gadgets 1 / ADE-1.bin / ade-dist / gnat-2.06-src.tgz / tar.out / fsf / gnat / ada / par-ch10.adb < prev next >

Wrap

Text File | 1996-09-28 | 23KB | 694 lines

------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- P A R . C H 1 0 -- -- -- -- B o d y -- -- -- -- $Revision: 1.66 $ -- -- -- -- Copyright (c) 1992,1993,1994 NYU, All Rights Reserved -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. -- -- -- ------------------------------------------------------------------------------ with Fname; use Fname; with Uname; use Uname; separate (Par) package body Ch10 is -- Local functions, used only in this chapter function P_Context_Clause return List_Id; function P_Subunit return Node_Id; procedure Unit_Display (Cunit : Node_Id; Loc : Source_Ptr); -- This procedure is used to generate a line of output for the a unit in -- the source program. Cunit is the node for the compilation unit, and -- Loc is the source location for the start of the unit in the source -- file (which is not necessarily the Sloc of the Cunit node). This -- output is written to the standard output file for use by gnatchop. ------------------------- -- 10.1.1 Compilation -- ------------------------- -- COMPILATION ::= {COMPILATION_UNIT} -- There is no specific parsing routine for a compilation, since we only -- permit a single compilation in a source file, so there is no explicit -- occurrence of compilations as such (our representation of a compilation -- is a series of separate source files). ------------------------------ -- 10.1.1 Compilation unit -- ------------------------------ -- COMPILATION_UNIT ::= -- CONTEXT_CLAUSE LIBRARY_ITEM -- | CONTEXT_CLAUSE SUBUNIT -- LIBRARY_ITEM ::= -- private LIBRARY_UNIT_DECLARATION -- | LIBRARY_UNIT_BODY -- | [private] LIBRARY_UNIT_RENAMING_DECLARATION -- LIBRARY_UNIT_DECLARATION ::= -- SUBPROGRAM_DECLARATION | PACKAGE_DECLARATION -- | GENERIC_DECLARATION | GENERIC_INSTANTIATION -- LIBRARY_UNIT_RENAMING_DECLARATION ::= -- PACKAGE_RENAMING_DECLARATION -- | GENERIC_RENAMING_DECLARATION -- | SUBPROGRAM_RENAMING_DECLARATION -- LIBRARY_UNIT_BODY ::= SUBPROGRAM_BODY | PACKAGE_BODY -- Error recovery: cannot raise Error_Resync. If an error occurs, tokens -- are skipped up to the next possible beginning of a compilation unit. function P_Compilation_Unit return Node_Id is Scan_State : Saved_Scan_State; Body_Node : Node_Id; Spec_Node : Node_Id; Specification_Node : Node_Id; Unit_Node : Node_Id; Comp_Unit_Node : Node_Id; Name_Node : Node_Id; Item : Node_Id; Private_Sloc : Source_Ptr; Cunit_Error_Flag : Boolean := False; -- This flag is set True if we have to scan for a compilation unit -- token. It is used to ensure clean termination in such cases by -- not insisting on being at the end of file, and, in the sytax only -- case by not scanning for additional compilation units. Cunit_Location : Source_Ptr; -- Location of unit for unit identification output (List_Unit option) Physical : Boolean; begin -- Set location of the compilation unit if unit list option set -- and we are in syntax check only mode if List_Units and then Operating_Mode = Check_Syntax then -- If we are at the start of the file, then we take the starting -- point for this unit as being at the start of the entire file. if Num_Library_Units = 0 then Cunit_Location := Source_First (Current_Source_File); Num_Library_Units := 1; -- If not at start of file, the starting point is the start of -- the line after the last token of the previous compilation unit, -- or the start of the current unit, whichever comes first. else Num_Library_Units := Num_Library_Units + 1; Cunit_Location := Prev_Token_Ptr; loop exit when Cunit_Location = Token_Ptr; if Source (Cunit_Location) in Line_Terminator then Skip_Line_Terminators (Cunit_Location, Physical); exit when Physical; end if; Cunit_Location := Cunit_Location + 1; end loop; end if; end if; -- Establish compilation unit node and scan context items Comp_Unit_Node := New_Node (N_Compilation_Unit, No_Location); Set_Cunit (Current_Source_Unit, Comp_Unit_Node); Set_Context_Items (Comp_Unit_Node, P_Context_Clause); -- Check for PRIVATE. Note that for the moment we allow this in -- Ada_83 mode, since we do not yet know if we are compiling a -- predefined unit, and if we are then it would be allowed anyway. if Token = Tok_Private then Private_Sloc := Token_Ptr; Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing); if Style_Check then Style.Check_Indentation; end if; Save_Scan_State (Scan_State); -- at PRIVATE Note_Feature (Private_Child, Token_Ptr); Scan; -- past PRIVATE if Token = Tok_Separate then Error_Msg_SP ("cannot have private subunits!"); elsif Token = Tok_Package then Scan; -- past PACKAGE if Token = Tok_Body then Restore_Scan_State (Scan_State); -- to PRIVATE Error_Msg_SC ("cannot have private package body!"); Scan; -- ignore PRIVATE else Restore_Scan_State (Scan_State); -- to PRIVATE Scan; -- past PRIVATE Set_Private_Present (Comp_Unit_Node, True); end if; end if; end if; -- Loop to find our way to a compilation unit token loop exit when Token in Token_Class_Cunit and then Token /= Tok_With; exit when Bad_Spelling_Of (Tok_Procedure) or else Bad_Spelling_Of (Tok_Package) or else Bad_Spelling_Of (Tok_Function) or else Bad_Spelling_Of (Tok_Generic); if Token = Tok_With then Error_Msg_SC ("misplaced WITH"); Append_List (P_Context_Clause, Context_Items (Comp_Unit_Node)); elsif Bad_Spelling_Of (Tok_With) then Append_List (P_Context_Clause, Context_Items (Comp_Unit_Node)); else Error_Msg_SC ("compilation unit expected"); Cunit_Error_Flag := True; Resync_Cunit; -- If we are at an end of file, then just quit, the above error -- message was complaint enough. if Token = Tok_EOF then return Error; end if; end if; end loop; -- We have a compilation unit token, so that's a reasonable choice for -- determining the standard casing convention used for keywords in case -- it hasn't already been done on seeing a WITH or PRIVATE. Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing); if Style_Check then Style.Check_Indentation; end if; -- Remaining processing depends on particular type of compilation unit if Token = Tok_Package then -- A common error is to omit the body keyword after package. We can -- often diagnose this early on (before getting loads of errors from -- contained subprogram bodies), by knowing that that the file we -- are compiling has a name that requires a body to be found. -- However, we do not do this check if we are operating in syntax -- checking only mode, because in that case there may be multiple -- units in the same file, and the file name is not a reliable guide. Save_Scan_State (Scan_State); Scan; -- past Package keyword if Token /= Tok_Body and then Operating_Mode /= Check_Syntax and then Get_Expected_Unit_Type (File_Name (Current_Source_File)) = Expect_Body then Error_Msg_BC ("keyword BODY expected here [see file name]"); Restore_Scan_State (Scan_State); Set_Unit (Comp_Unit_Node, P_Package (Pf_Pbod)); else Restore_Scan_State (Scan_State); Set_Unit (Comp_Unit_Node, P_Package (Pf_Decl_Gins_Pbod_Rnam)); end if; elsif Token = Tok_Generic then Set_Unit (Comp_Unit_Node, P_Generic); elsif Token = Tok_Separate then Set_Unit (Comp_Unit_Node, P_Subunit); else pragma Assert (Token = Tok_Procedure or else Token = Tok_Function); Set_Unit (Comp_Unit_Node, P_Subprogram (Pf_Decl_Gins_Pbod_Rnam)); -- A little bit of an error recovery check here. If we just scanned -- a subprogram declaration (as indicated by an SIS entry being -- active), then if the following token is BEGIN or an identifier, -- or a token which can reasonably start a declaration but cannot -- start a compilation unit, then we assume that the semicolon in -- the declaration should have been IS. if SIS_Entry_Active then if Token = Tok_Begin or else Token = Tok_Identifier or else Token in Token_Class_Deckn then Push_Scope_Stack; Scope.Table (Scope.Last).Etyp := E_Name; Scope.Table (Scope.Last).Sloc := SIS_Sloc; Scope.Table (Scope.Last).Ecol := SIS_Ecol; Scope.Table (Scope.Last).Lreq := False; SIS_Entry_Active := False; Error_Msg_SP (""";"" should be IS!"); Body_Node := Unit (Comp_Unit_Node); Specification_Node := Specification (Body_Node); Change_Node (Body_Node, N_Subprogram_Body); Set_Specification (Body_Node, Specification_Node); Parse_Decls_Begin_End (Body_Node); Set_Unit (Comp_Unit_Node, Body_Node); end if; end if; end if; -- Here is where we set the Sloc field of the N_Compilation_Unit node, -- which must point to the name of the unit, which is a bit hard to -- find in some cases (which is why we set it in the node!) Unit_Node := Unit (Comp_Unit_Node); -- Only try this if we got an OK unit! if Unit_Node /= Error then if Nkind (Unit_Node) = N_Subunit then Unit_Node := Proper_Body (Unit_Node); end if; if Nkind (Unit_Node) in N_Generic_Declaration then Unit_Node := Specification (Unit_Node); end if; if Nkind (Unit_Node) = N_Package_Declaration or else Nkind (Unit_Node) = N_Subprogram_Declaration or else Nkind (Unit_Node) = N_Subprogram_Body or else Nkind (Unit_Node) = N_Subprogram_Renaming_Declaration then Unit_Node := Specification (Unit_Node); elsif Nkind (Unit_Node) = N_Subprogram_Renaming_Declaration then Note_Feature (Library_Unit_Renaming, Sloc (Unit_Node)); if Ada_83 then Error_Msg_N ("(Ada 83) library unit renaming not allowed", Unit_Node); end if; end if; if Nkind (Unit_Node) = N_Task_Body or else Nkind (Unit_Node) = N_Protected_Body then Name_Node := Defining_Identifier (Unit_Node); else Name_Node := Defining_Unit_Name (Unit_Node); end if; Set_Sloc (Comp_Unit_Node, Sloc (Name_Node)); -- Set Entity field in file table. Easier now that we have name! -- Note that this is also skipped if we had a bad unit if Nkind (Name_Node) = N_Defining_Program_Unit_Name then Set_Cunit_Entity (Current_Source_Unit, Defining_Identifier (Name_Node)); else Set_Cunit_Entity (Current_Source_Unit, Name_Node); end if; Set_Unit_Name (Current_Source_Unit, Get_Unit_Name (Unit (Comp_Unit_Node))); -- If we had a bad unit, make sure the fatal flag is set in the file -- table entry, since this is surely a fatal error and also set our -- flag to inhibit the requirement that we be at end of file. else Cunit_Error_Flag := True; Set_Fatal_Error (Current_Source_Unit); end if; -- Clear away any missing semicolon indication, we are done with that -- unit, so what's done is done, and we don't want anything hanging -- around from the attempt to parse it! SIS_Entry_Active := False; -- Any final pragmas get appended to the context clause if Token = Tok_Pragma then Set_Following_Pragmas (Comp_Unit_Node, New_List); P_Pragmas_Opt (Following_Pragmas (Comp_Unit_Node)); end if; -- Ada 83 error checks if Ada_83 then -- Check we did not with any child units Item := First (Context_Items (Comp_Unit_Node)); while Present (Item) loop if Nkind (Item) = N_With_Clause and then Nkind (Name (Item)) /= N_Identifier then Error_Msg_N ("(Ada 83) child units not allowed", Item); end if; Item := Next (Item); end loop; -- Check that we did not have a PRIVATE keyword present if Private_Present (Comp_Unit_Node) then Error_Msg ("(Ada 83) private units not allowed", Private_Sloc); end if; end if; -- If no serious error, then output possible unit information line if not Cunit_Error_Flag and then List_Units and then Operating_Mode = Check_Syntax then Unit_Display (Comp_Unit_Node, Cunit_Location); end if; -- And now we should be at the end of file, except that if we had to -- scan for a compilation unit, then we don't check this, since it -- seems in practice to often make things worse, and we already gave -- a serious error message. if Token /= Tok_EOF and then not Cunit_Error_Flag then -- If we are not at end of file, then fatal error unless we are -- syntax checking only mode, where we do allow additional units -- by making a recursive call to this routine. Skip this message -- if we already had some fatal error. if Operating_Mode = Check_Syntax then return P_Compilation_Unit; else if not Fatal_Error (Current_Source_Unit) then if Token in Token_Class_Cunit then Error_Msg_SC ("end of file expected, " & "file can have only one compilation unit"); else Error_Msg_SC ("end of file expected"); end if; end if; return Error; end if; -- This is the normal return else return Comp_Unit_Node; end if; exception -- An error resync is a serious bomb, so indicate result unit no good when Error_Resync => Set_Fatal_Error (Current_Source_Unit); return Error; end P_Compilation_Unit; -------------------------- -- 10.1.1 Library Item -- -------------------------- -- Parsed by P_Compilation_Unit (10.1.1) -------------------------------------- -- 10.1.1 Library Unit Declaration -- -------------------------------------- -- Parsed by P_Compilation_Unit (10.1.1) ------------------------------------------------ -- 10.1.1 Library Unit Renaming Declaration -- ------------------------------------------------ -- Parsed by P_Compilation_Unit (10.1.1) ------------------------------- -- 10.1.1 Library Unit Body -- ------------------------------- -- Parsed by P_Compilation_Unit (10.1.1) ------------------------------ -- 10.1.1 Parent Unit Name -- ------------------------------ -- Parsed (as a name) by its parent construct ---------------------------- -- 10.1.2 Context Clause -- ---------------------------- -- CONTEXT_CLAUSE ::= {CONTEXT_ITEM} -- CONTEXT_ITEM ::= WITH_CLAUSE | USE_CLAUSE -- WITH_CLAUSE ::= -- with library_unit_NAME {,library_unit_NAME}; -- Error recovery: Cannot raise Error_Resync function P_Context_Clause return List_Id is Item_List : List_Id; Scan_State : Saved_Scan_State; With_Node : Node_Id; Id_Node : Node_Id; First_Flag : Boolean; begin Item_List := New_List; -- Get keyword casing from WITH keyword in case not set yet if Token = Tok_With then Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing); end if; -- Loop through context items loop if Style_Check then Style.Check_Indentation; end if; -- Gather any pragmas appearing in the context clause P_Pragmas_Opt (Item_List); -- Processing for WITH clause if Token = Tok_With then Scan; -- past WITH First_Flag := True; -- Loop through names in one with clause, generating a separate -- N_With_Clause node for each nam encountered. loop With_Node := New_Node (N_With_Clause, Token_Ptr); Append (With_Node, Item_List); -- Note that we allow with'ing of child units, even in Ada 83 -- mode, since presumably if this is not desired, then the -- compilation of the child unit itself is the place where -- such an "error" should be caught. Set_Name (With_Node, P_Qualified_Simple_Name); Set_First_Name (With_Node, First_Flag); First_Flag := False; exit when Token /= Tok_Comma; Scan; -- past comma end loop; Set_Last_Name (With_Node, True); TF_Semicolon; -- Processing for USE clause elsif Token = Tok_Use then Append (P_Use_Clause, Item_List); -- Anything else is end of context clause else exit; end if; end loop; return Item_List; end P_Context_Clause; -------------------------- -- 10.1.2 Context Item -- -------------------------- -- Parsed by P_Context_Clause (10.1.2) ------------------------- -- 10.1.2 With Clause -- ------------------------- -- Parsed by P_Context_Clause (10.1.2) ----------------------- -- 10.1.3 Body Stub -- ----------------------- -- Subprogram stub parsed by P_Subprogram (6.1) -- Package stub parsed by P_Package (7.1) -- Task stub parsed by P_Task (9.1) -- Protected stub parsed by P_Protected (9.4) ---------------------------------- -- 10.1.3 Subprogram Body Stub -- ---------------------------------- -- Parsed by P_Subprogram (6.1) ------------------------------- -- 10.1.3 Package Body Stub -- ------------------------------- -- Parsed by P_Package (7.1) ---------------------------- -- 10.1.3 Task Body Stub -- ---------------------------- -- Parsed by P_Task (9.1) --------------------------------- -- 10.1.3 Protected Body Stub -- --------------------------------- -- Parsed by P_Protected (9.4) --------------------- -- 10.1.3 Subunit -- --------------------- -- SUBUNIT ::= separate (PARENT_UNIT_NAME) PROPER_BODY -- PARENT_UNIT_NAME ::= NAME -- The caller has checked that the initial token is SEPARATE -- Error recovery: cannot raise Error_Resync function P_Subunit return Node_Id is Subunit_Node : Node_Id; Body_Node : Node_Id; begin Subunit_Node := New_Node (N_Subunit, Token_Ptr); Body_Node := Error; -- in case no good body found Scan; -- past SEPARATE; T_Left_Paren; Set_Name (Subunit_Node, P_Qualified_Simple_Name); T_Right_Paren; if Token = Tok_Semicolon then Error_Msg_SC ("unexpected semicolon ignored"); Scan; end if; if Token = Tok_Function or else Token = Tok_Procedure then Body_Node := P_Subprogram (Pf_Pbod); elsif Token = Tok_Package then Body_Node := P_Package (Pf_Pbod); elsif Token = Tok_Protected then Scan; -- past PROTECTED if Token = Tok_Body then Body_Node := P_Protected; else Error_Msg_AP ("BODY expected"); return Error; end if; elsif Token = Tok_Task then Scan; -- past TASK if Token = Tok_Body then Body_Node := P_Task; else Error_Msg_AP ("BODY expected"); return Error; end if; else Error_Msg_SC ("proper body expected"); return Error; end if; Set_Proper_Body (Subunit_Node, Body_Node); return Subunit_Node; end P_Subunit; ------------------ -- Unit_Display -- ------------------ procedure Unit_Display (Cunit : Node_Id; Loc : Source_Ptr) is Unum : constant Unit_Number_Type := Get_Cunit_Unit_Number (Cunit); Sind : constant Source_File_Index := Source_Index (Unum); Line : constant Logical_Line_Number := Get_Line_Number (Loc); Unam : constant Unit_Name_Type := Unit_Name (Unum); begin if List_Units then Write_Str ("Unit "); Write_Unit_Name (Unit_Name (Unum)); Write_Str (" line "); Write_Int (Int (Line)); Write_Str (", file offset "); Write_Int (Int (Loc) - Int (Source_Text (Sind)'First)); Write_Str (", file name "); Write_Name (Get_File_Name (Unam)); Write_Eol; end if; end Unit_Display; end Ch10;