gcc/ada/par-ch10.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             P A R . C H 1 0                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 pragma Style_Checks (All_Checks);
  27 --  Turn off subprogram body ordering check. Subprograms are in order
  28 --  by RM section rather than alphabetical
  29
  30 with Fname.UF; use Fname.UF;
  31 with Uname;    use Uname;
  32
  33 separate (Par)
  34 package body Ch10 is
  35
  36    --  Local functions, used only in this chapter
  37
  38    function P_Context_Clause    return List_Id;
  39    function P_Subunit           return Node_Id;
  40
  41    function Set_Location return Source_Ptr;
  42    --  The current compilation unit starts with Token at Token_Ptr. This
  43    --  function determines the corresponding source location for the start
  44    --  of the unit, including any preceding comment lines.
  45
  46    procedure Unit_Display
  47      (Cunit      : Node_Id;
  48       Loc        : Source_Ptr;
  49       SR_Present : Boolean);
  50    --  This procedure is used to generate a line of output for a unit in
  51    --  the source program. Cunit is the node for the compilation unit, and
  52    --  Loc is the source location for the start of the unit in the source
  53    --  file (which is not necessarily the Sloc of the Cunit node). This
  54    --  output is written to the standard output file for use by gnatchop.
  55
  56    procedure Unit_Location (Sind : Source_File_Index; Loc : Source_Ptr);
  57    --  This routine has the same calling sequence as Unit_Display, but
  58    --  it outputs only the line number and offset of the location, Loc,
  59    --  using Cunit to obtain the proper source file index.
  60
  61    -------------------------
  62    -- 10.1.1  Compilation --
  63    -------------------------
  64
  65    --  COMPILATION ::= {COMPILATION_UNIT}
  66
  67    --  There is no specific parsing routine for a compilation, since we only
  68    --  permit a single compilation in a source file, so there is no explicit
  69    --  occurrence of compilations as such (our representation of a compilation
  70    --  is a series of separate source files).
  71
  72    ------------------------------
  73    -- 10.1.1  Compilation unit --
  74    ------------------------------
  75
  76    --  COMPILATION_UNIT ::=
  77    --    CONTEXT_CLAUSE LIBRARY_ITEM
  78    --  | CONTEXT_CLAUSE SUBUNIT
  79
  80    --  LIBRARY_ITEM ::=
  81    --    private LIBRARY_UNIT_DECLARATION
  82    --  | LIBRARY_UNIT_BODY
  83    --  | [private] LIBRARY_UNIT_RENAMING_DECLARATION
  84
  85    --  LIBRARY_UNIT_DECLARATION ::=
  86    --    SUBPROGRAM_DECLARATION | PACKAGE_DECLARATION
  87    --  | GENERIC_DECLARATION    | GENERIC_INSTANTIATION
  88
  89    --  LIBRARY_UNIT_RENAMING_DECLARATION ::=
  90    --    PACKAGE_RENAMING_DECLARATION
  91    --  | GENERIC_RENAMING_DECLARATION
  92    --  | SUBPROGRAM_RENAMING_DECLARATION
  93
  94    --  LIBRARY_UNIT_BODY ::= SUBPROGRAM_BODY | PACKAGE_BODY
  95
  96    --  Error recovery: cannot raise Error_Resync. If an error occurs, tokens
  97    --  are skipped up to the next possible beginning of a compilation unit.
  98
  99    --  Note: if only configuration pragmas are found, Empty is returned
 100
 101    --  Note: in syntax-only mode, it is possible for P_Compilation_Unit
 102    --  to return strange things that are not really compilation units.
 103    --  This is done to help out gnatchop when it is faced with nonsense.
 104
 105    function P_Compilation_Unit return Node_Id is
 106       Scan_State         : Saved_Scan_State;
 107       Body_Node          : Node_Id;
 108       Specification_Node : Node_Id;
 109       Unit_Node          : Node_Id;
 110       Comp_Unit_Node     : Node_Id;
 111       Name_Node          : Node_Id;
 112       Item               : Node_Id;
 113       Private_Sloc       : Source_Ptr := No_Location;
 114       Config_Pragmas     : List_Id;
 115       P                  : Node_Id;
 116       SR_Present         : Boolean;
 117
 118       Cunit_Error_Flag : Boolean := False;
 119       --  This flag is set True if we have to scan for a compilation unit
 120       --  token. It is used to ensure clean termination in such cases by
 121       --  not insisting on being at the end of file, and, in the syntax only
 122       --  case by not scanning for additional compilation units.
 123
 124       Cunit_Location : Source_Ptr;
 125       --  Location of unit for unit identification output (List_Unit option)
 126
 127    begin
 128       Num_Library_Units := Num_Library_Units + 1;
 129
 130       --  Set location of the compilation unit if unit list option set
 131       --  and we are in syntax check only mode
 132
 133       if List_Units and then Operating_Mode = Check_Syntax then
 134          Cunit_Location := Set_Location;
 135       else
 136          Cunit_Location := No_Location;
 137       end if;
 138
 139       --  Deal with initial pragmas
 140
 141       Config_Pragmas := No_List;
 142
 143       --  If we have an initial Source_Reference pragma, then remember the fact
 144       --  to generate an NR parameter in the output line.
 145
 146       SR_Present := False;
 147
 148       if Token = Tok_Pragma then
 149          Save_Scan_State (Scan_State);
 150          Item := P_Pragma;
 151
 152          if Item = Error
 153            or else Pragma_Name (Item) /= Name_Source_Reference
 154          then
 155             Restore_Scan_State (Scan_State);
 156
 157          else
 158             SR_Present := True;
 159
 160             --  If first unit, record the file name for gnatchop use
 161
 162             if Operating_Mode = Check_Syntax
 163               and then List_Units
 164               and then Num_Library_Units = 1
 165             then
 166                Write_Str ("Source_Reference pragma for file """);
 167                Write_Name (Full_Ref_Name (Current_Source_File));
 168                Write_Char ('"');
 169                Write_Eol;
 170             end if;
 171
 172             Config_Pragmas := New_List (Item);
 173          end if;
 174       end if;
 175
 176       --  Scan out any configuration pragmas
 177
 178       while Token = Tok_Pragma loop
 179          Save_Scan_State (Scan_State);
 180          Item := P_Pragma;
 181
 182          if Item = Error
 183            or else not Is_Configuration_Pragma_Name (Pragma_Name (Item))
 184          then
 185             Restore_Scan_State (Scan_State);
 186             exit;
 187          end if;
 188
 189          if Config_Pragmas = No_List then
 190             Config_Pragmas := Empty_List;
 191
 192             if Operating_Mode = Check_Syntax and then List_Units then
 193                Write_Str ("Configuration pragmas at");
 194                Unit_Location (Current_Source_File, Cunit_Location);
 195                Write_Eol;
 196             end if;
 197          end if;
 198
 199          Append (Item, Config_Pragmas);
 200          Cunit_Location := Set_Location;
 201       end loop;
 202
 203       --  Establish compilation unit node and scan context items
 204
 205       Comp_Unit_Node := New_Node (N_Compilation_Unit, No_Location);
 206       Set_Cunit (Current_Source_Unit, Comp_Unit_Node);
 207       Set_Context_Items (Comp_Unit_Node, P_Context_Clause);
 208       Set_Aux_Decls_Node
 209         (Comp_Unit_Node, New_Node (N_Compilation_Unit_Aux, No_Location));
 210
 211       if Present (Config_Pragmas) then
 212
 213          --  Check for case of only configuration pragmas present
 214
 215          if Token = Tok_EOF
 216            and then Is_Empty_List (Context_Items (Comp_Unit_Node))
 217          then
 218             if Operating_Mode = Check_Syntax then
 219                return Empty;
 220
 221             else
 222                Item := First (Config_Pragmas);
 223                Error_Msg_N
 224                  ("cannot compile configuration pragmas with gcc!", Item);
 225                Error_Msg_N
 226                  ("\use gnatchop -c to process configuration pragmas!", Item);
 227                raise Unrecoverable_Error;
 228             end if;
 229
 230          --  Otherwise configuration pragmas are simply prepended to the
 231          --  context of the current unit.
 232
 233          else
 234             Append_List (Context_Items (Comp_Unit_Node), Config_Pragmas);
 235             Set_Context_Items (Comp_Unit_Node, Config_Pragmas);
 236          end if;
 237       end if;
 238
 239       --  Check for PRIVATE. Note that for the moment we allow this in
 240       --  Ada_83 mode, since we do not yet know if we are compiling a
 241       --  predefined unit, and if we are then it would be allowed anyway.
 242
 243       if Token = Tok_Private then
 244          Private_Sloc := Token_Ptr;
 245          Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing);
 246
 247          if Style_Check then
 248             Style.Check_Indentation;
 249          end if;
 250
 251          Save_Scan_State (Scan_State); -- at PRIVATE
 252          Scan; -- past PRIVATE
 253
 254          if Token = Tok_Separate then
 255             Error_Msg_SP ("cannot have private subunits!");
 256
 257          elsif Token = Tok_Package then
 258             Scan; -- past PACKAGE
 259
 260             if Token = Tok_Body then
 261                Restore_Scan_State (Scan_State); -- to PRIVATE
 262                Error_Msg_SC ("cannot have private package body!");
 263                Scan; -- ignore PRIVATE
 264
 265             else
 266                Restore_Scan_State (Scan_State); -- to PRIVATE
 267                Scan; -- past PRIVATE
 268                Set_Private_Present (Comp_Unit_Node, True);
 269             end if;
 270
 271          elsif Token = Tok_Procedure
 272            or else Token = Tok_Function
 273            or else Token = Tok_Generic
 274          then
 275             Set_Private_Present (Comp_Unit_Node, True);
 276          end if;
 277       end if;
 278
 279       --  Loop to find our way to a compilation unit token
 280
 281       loop
 282          exit when Token in Token_Class_Cunit and then Token /= Tok_With;
 283
 284          exit when Bad_Spelling_Of (Tok_Package)
 285            or else Bad_Spelling_Of (Tok_Function)
 286            or else Bad_Spelling_Of (Tok_Generic)
 287            or else Bad_Spelling_Of (Tok_Separate)
 288            or else Bad_Spelling_Of (Tok_Procedure);
 289
 290          --  Allow task and protected for nice error recovery purposes
 291
 292          exit when Token = Tok_Task
 293            or else Token = Tok_Protected;
 294
 295          if Token = Tok_With then
 296             Error_Msg_SC ("misplaced WITH");
 297             Append_List (P_Context_Clause, Context_Items (Comp_Unit_Node));
 298
 299          elsif Bad_Spelling_Of (Tok_With) then
 300             Append_List (P_Context_Clause, Context_Items (Comp_Unit_Node));
 301
 302          else
 303             if Operating_Mode = Check_Syntax and then Token = Tok_EOF then
 304                Error_Msg_SC ("?file contains no compilation units");
 305             else
 306                Error_Msg_SC ("compilation unit expected");
 307                Cunit_Error_Flag := True;
 308                Resync_Cunit;
 309             end if;
 310
 311             --  If we are at an end of file, then just quit, the above error
 312             --  message was complaint enough.
 313
 314             if Token = Tok_EOF then
 315                return Error;
 316             end if;
 317          end if;
 318       end loop;
 319
 320       --  We have a compilation unit token, so that's a reasonable choice for
 321       --  determining the standard casing convention used for keywords in case
 322       --  it hasn't already been done on seeing a WITH or PRIVATE.
 323
 324       Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing);
 325
 326       if Style_Check then
 327          Style.Check_Indentation;
 328       end if;
 329
 330       --  Remaining processing depends on particular type of compilation unit
 331
 332       if Token = Tok_Package then
 333
 334          --  A common error is to omit the body keyword after package. We can
 335          --  often diagnose this early on (before getting loads of errors from
 336          --  contained subprogram bodies), by knowing that the file we
 337          --  are compiling has a name that requires a body to be found.
 338
 339          Save_Scan_State (Scan_State);
 340          Scan; -- past Package keyword
 341
 342          if Token /= Tok_Body
 343            and then
 344              Get_Expected_Unit_Type
 345                (File_Name (Current_Source_File)) = Expect_Body
 346          then
 347             Error_Msg_BC ("keyword BODY expected here [see file name]");
 348             Restore_Scan_State (Scan_State);
 349             Set_Unit (Comp_Unit_Node, P_Package (Pf_Pbod));
 350          else
 351             Restore_Scan_State (Scan_State);
 352             Set_Unit (Comp_Unit_Node, P_Package (Pf_Decl_Gins_Pbod_Rnam));
 353          end if;
 354
 355       elsif Token = Tok_Generic then
 356          Set_Unit (Comp_Unit_Node, P_Generic);
 357
 358       elsif Token = Tok_Separate then
 359          Set_Unit (Comp_Unit_Node, P_Subunit);
 360
 361       elsif Token = Tok_Function
 362         or else Token = Tok_Not
 363         or else Token = Tok_Overriding
 364         or else Token = Tok_Procedure
 365       then
 366          Set_Unit (Comp_Unit_Node, P_Subprogram (Pf_Decl_Gins_Pbod_Rnam));
 367
 368          --  A little bit of an error recovery check here. If we just scanned
 369          --  a subprogram declaration (as indicated by an SIS entry being
 370          --  active), then if the following token is BEGIN or an identifier,
 371          --  or a token which can reasonably start a declaration but cannot
 372          --  start a compilation unit, then we assume that the semicolon in
 373          --  the declaration should have been IS.
 374
 375          if SIS_Entry_Active then
 376
 377             if Token = Tok_Begin
 378                or else Token = Tok_Identifier
 379                or else Token in Token_Class_Deckn
 380             then
 381                Push_Scope_Stack;
 382                Scope.Table (Scope.Last).Etyp := E_Name;
 383                Scope.Table (Scope.Last).Sloc := SIS_Sloc;
 384                Scope.Table (Scope.Last).Ecol := SIS_Ecol;
 385                Scope.Table (Scope.Last).Lreq := False;
 386                SIS_Entry_Active := False;
 387
 388                --  If we had a missing semicolon in the declaration, then
 389                --  change the message to from <missing ";"> to <missing "is">
 390
 391                if SIS_Missing_Semicolon_Message /= No_Error_Msg then
 392                   Change_Error_Text     -- Replace: "missing "";"" "
 393                     (SIS_Missing_Semicolon_Message, "missing IS");
 394
 395                --  Otherwise we saved the semicolon position, so complain
 396
 397                else
 398                   Error_Msg (""";"" should be IS", SIS_Semicolon_Sloc);
 399                end if;
 400
 401                Body_Node := Unit (Comp_Unit_Node);
 402                Specification_Node := Specification (Body_Node);
 403                Change_Node (Body_Node, N_Subprogram_Body);
 404                Set_Specification (Body_Node, Specification_Node);
 405                Parse_Decls_Begin_End (Body_Node);
 406                Set_Unit (Comp_Unit_Node, Body_Node);
 407             end if;
 408
 409          --  If we scanned a subprogram body, make sure we did not have private
 410
 411          elsif Private_Sloc /= No_Location
 412            and then
 413              Nkind (Unit (Comp_Unit_Node)) not in N_Subprogram_Instantiation
 414            and then
 415              Nkind (Unit (Comp_Unit_Node)) /= N_Subprogram_Renaming_Declaration
 416          then
 417             Error_Msg ("cannot have private subprogram body", Private_Sloc);
 418
 419          --  P_Subprogram can yield an abstract subprogram, but this cannot
 420          --  be a compilation unit. Treat as a subprogram declaration.
 421
 422          elsif
 423            Nkind (Unit (Comp_Unit_Node)) = N_Abstract_Subprogram_Declaration
 424          then
 425             Error_Msg_N
 426               ("compilation unit cannot be abstract subprogram",
 427                  Unit (Comp_Unit_Node));
 428
 429             Unit_Node :=
 430               New_Node (N_Subprogram_Declaration, Sloc (Comp_Unit_Node));
 431             Set_Specification (Unit_Node,
 432               Specification (Unit (Comp_Unit_Node)));
 433             Set_Unit (Comp_Unit_Node, Unit_Node);
 434          end if;
 435
 436       --  Otherwise we have TASK. This is not really an acceptable token,
 437       --  but we accept it to improve error recovery.
 438
 439       elsif Token = Tok_Task then
 440          Scan; -- Past TASK
 441
 442          if Token = Tok_Type then
 443             Error_Msg_SP
 444               ("task type cannot be used as compilation unit");
 445          else
 446             Error_Msg_SP
 447               ("task declaration cannot be used as compilation unit");
 448          end if;
 449
 450          --  If in check syntax mode, accept the task anyway. This is done
 451          --  particularly to improve the behavior of GNATCHOP in this case.
 452
 453          if Operating_Mode = Check_Syntax then
 454             Set_Unit (Comp_Unit_Node, P_Task);
 455
 456          --  If not in syntax only mode, treat this as horrible error
 457
 458          else
 459             Cunit_Error_Flag := True;
 460             return Error;
 461          end if;
 462
 463       else pragma Assert (Token = Tok_Protected);
 464          Scan; -- Past PROTECTED
 465
 466          if Token = Tok_Type then
 467             Error_Msg_SP
 468               ("protected type cannot be used as compilation unit");
 469          else
 470             Error_Msg_SP
 471               ("protected declaration cannot be used as compilation unit");
 472          end if;
 473
 474          --  If in check syntax mode, accept protected anyway. This is done
 475          --  particularly to improve the behavior of GNATCHOP in this case.
 476
 477          if Operating_Mode = Check_Syntax then
 478             Set_Unit (Comp_Unit_Node, P_Protected);
 479
 480          --  If not in syntax only mode, treat this as horrible error
 481
 482          else
 483             Cunit_Error_Flag := True;
 484             return Error;
 485          end if;
 486       end if;
 487
 488       --  Here is where locate the compilation unit entity. This is a little
 489       --  tricky, since it is buried in various places.
 490
 491       Unit_Node := Unit (Comp_Unit_Node);
 492
 493       --  Another error from which it is hard to recover
 494
 495       if Nkind (Unit_Node) = N_Subprogram_Body_Stub
 496         or else Nkind (Unit_Node) = N_Package_Body_Stub
 497       then
 498          Cunit_Error_Flag := True;
 499          return Error;
 500       end if;
 501
 502       --  Only try this if we got an OK unit!
 503
 504       if Unit_Node /= Error then
 505          if Nkind (Unit_Node) = N_Subunit then
 506             Unit_Node := Proper_Body (Unit_Node);
 507          end if;
 508
 509          if Nkind (Unit_Node) in N_Generic_Declaration then
 510             Unit_Node := Specification (Unit_Node);
 511          end if;
 512
 513          if Nkind (Unit_Node) = N_Package_Declaration
 514            or else Nkind (Unit_Node) = N_Subprogram_Declaration
 515            or else Nkind (Unit_Node) = N_Subprogram_Body
 516            or else Nkind (Unit_Node) = N_Subprogram_Renaming_Declaration
 517          then
 518             Unit_Node := Specification (Unit_Node);
 519
 520          elsif Nkind (Unit_Node) = N_Subprogram_Renaming_Declaration then
 521             if Ada_Version = Ada_83 then
 522                Error_Msg_N
 523                  ("(Ada 83) library unit renaming not allowed", Unit_Node);
 524             end if;
 525          end if;
 526
 527          if Nkind (Unit_Node) = N_Task_Body
 528            or else Nkind (Unit_Node) = N_Protected_Body
 529            or else Nkind (Unit_Node) = N_Task_Type_Declaration
 530            or else Nkind (Unit_Node) = N_Protected_Type_Declaration
 531            or else Nkind (Unit_Node) = N_Single_Task_Declaration
 532            or else Nkind (Unit_Node) = N_Single_Protected_Declaration
 533          then
 534             Name_Node := Defining_Identifier (Unit_Node);
 535
 536          elsif Nkind (Unit_Node) = N_Function_Instantiation
 537            or else Nkind (Unit_Node) = N_Function_Specification
 538            or else Nkind (Unit_Node) = N_Generic_Function_Renaming_Declaration
 539            or else Nkind (Unit_Node) = N_Generic_Package_Renaming_Declaration
 540            or else Nkind (Unit_Node) = N_Generic_Procedure_Renaming_Declaration
 541            or else Nkind (Unit_Node) = N_Package_Body
 542            or else Nkind (Unit_Node) = N_Package_Instantiation
 543            or else Nkind (Unit_Node) = N_Package_Renaming_Declaration
 544            or else Nkind (Unit_Node) = N_Package_Specification
 545            or else Nkind (Unit_Node) = N_Procedure_Instantiation
 546            or else Nkind (Unit_Node) = N_Procedure_Specification
 547          then
 548             Name_Node := Defining_Unit_Name (Unit_Node);
 549
 550          --  Anything else is a serious error, abandon scan
 551
 552          else
 553             raise Error_Resync;
 554          end if;
 555
 556          Set_Sloc (Comp_Unit_Node, Sloc (Name_Node));
 557          Set_Sloc (Aux_Decls_Node (Comp_Unit_Node), Sloc (Name_Node));
 558
 559          --  Set Entity field in file table. Easier now that we have name!
 560          --  Note that this is also skipped if we had a bad unit
 561
 562          if Nkind (Name_Node) = N_Defining_Program_Unit_Name then
 563             Set_Cunit_Entity
 564               (Current_Source_Unit, Defining_Identifier (Name_Node));
 565          else
 566             Set_Cunit_Entity (Current_Source_Unit, Name_Node);
 567          end if;
 568
 569          Set_Unit_Name
 570            (Current_Source_Unit, Get_Unit_Name (Unit (Comp_Unit_Node)));
 571
 572       --  If we had a bad unit, make sure the fatal flag is set in the file
 573       --  table entry, since this is surely a fatal error and also set our
 574       --  flag to inhibit the requirement that we be at end of file.
 575
 576       else
 577          Cunit_Error_Flag := True;
 578          Set_Fatal_Error (Current_Source_Unit);
 579       end if;
 580
 581       --  Clear away any missing semicolon indication, we are done with that
 582       --  unit, so what's done is done, and we don't want anything hanging
 583       --  around from the attempt to parse it!
 584
 585       SIS_Entry_Active := False;
 586
 587       --  Scan out pragmas after unit
 588
 589       while Token = Tok_Pragma loop
 590          Save_Scan_State (Scan_State);
 591
 592          --  If we are in syntax scan mode allowing multiple units, then start
 593          --  the next unit if we encounter a configuration pragma, or a source
 594          --  reference pragma. We take care not to actually scan the pragma in
 595          --  this case (we don't want it to take effect for the current unit).
 596
 597          if Operating_Mode = Check_Syntax then
 598             Scan;  -- past Pragma
 599
 600             if Token = Tok_Identifier
 601               and then
 602                 (Is_Configuration_Pragma_Name (Token_Name)
 603                    or else Token_Name = Name_Source_Reference)
 604             then
 605                Restore_Scan_State (Scan_State); -- to Pragma
 606                exit;
 607             end if;
 608          end if;
 609
 610          --  Otherwise eat the pragma, it definitely belongs with the
 611          --  current unit, and not with the following unit.
 612
 613          Restore_Scan_State (Scan_State); -- to Pragma
 614          P := P_Pragma;
 615
 616          if No (Pragmas_After (Aux_Decls_Node (Comp_Unit_Node))) then
 617             Set_Pragmas_After
 618               (Aux_Decls_Node (Comp_Unit_Node), New_List);
 619          end if;
 620
 621          Append (P, Pragmas_After (Aux_Decls_Node (Comp_Unit_Node)));
 622       end loop;
 623
 624       --  Cancel effect of any outstanding pragma Warnings (Off)
 625
 626       Set_Warnings_Mode_On (Scan_Ptr);
 627
 628       --  Ada 83 error checks
 629
 630       if Ada_Version = Ada_83 then
 631
 632          --  Check we did not with any child units
 633
 634          Item := First (Context_Items (Comp_Unit_Node));
 635
 636          while Present (Item) loop
 637             if Nkind (Item) = N_With_Clause
 638               and then Nkind (Name (Item)) /= N_Identifier
 639             then
 640                Error_Msg_N ("(Ada 83) child units not allowed", Item);
 641             end if;
 642
 643             Next (Item);
 644          end loop;
 645
 646          --  Check that we did not have a PRIVATE keyword present
 647
 648          if Private_Present (Comp_Unit_Node) then
 649             Error_Msg
 650               ("(Ada 83) private units not allowed", Private_Sloc);
 651          end if;
 652       end if;
 653
 654       --  If no serious error, then output possible unit information line
 655       --  for gnatchop if we are in syntax only, list units mode.
 656
 657       if not Cunit_Error_Flag
 658         and then List_Units
 659         and then Operating_Mode = Check_Syntax
 660       then
 661          Unit_Display (Comp_Unit_Node, Cunit_Location, SR_Present);
 662       end if;
 663
 664       --  And now we should be at the end of file
 665
 666       if Token /= Tok_EOF then
 667
 668          --  If we already had to scan for a compilation unit, then don't
 669          --  give any further error message, since it just seems to make
 670          --  things worse, and we already gave a serious error message.
 671
 672          if Cunit_Error_Flag then
 673             null;
 674
 675          --  If we are in check syntax mode, then we allow multiple units
 676          --  so we just return with Token not set to Tok_EOF and no message.
 677
 678          elsif Operating_Mode = Check_Syntax then
 679             return Comp_Unit_Node;
 680
 681          --  We also allow multiple units if we are in multiple unit mode
 682
 683          elsif Multiple_Unit_Index /= 0 then
 684
 685             --  Skip tokens to end of file, so that the -gnatl listing
 686             --  will be complete in this situation, but no need to parse
 687             --  the remaining units; no style checking either.
 688
 689             declare
 690                Save_Style_Check : constant Boolean := Style_Check;
 691
 692             begin
 693                Style_Check := False;
 694
 695                while Token /= Tok_EOF loop
 696                   Scan;
 697                end loop;
 698
 699                Style_Check := Save_Style_Check;
 700             end;
 701
 702             return Comp_Unit_Node;
 703
 704          --  Otherwise we have an error. We suppress the error message
 705          --  if we already had a fatal error, since this stops junk
 706          --  cascaded messages in some situations.
 707
 708          else
 709             if not Fatal_Error (Current_Source_Unit) then
 710                if Token in Token_Class_Cunit then
 711                   Error_Msg_SC
 712                     ("end of file expected, " &
 713                      "file can have only one compilation unit");
 714                else
 715                   Error_Msg_SC ("end of file expected");
 716                end if;
 717             end if;
 718          end if;
 719
 720          --  Skip tokens to end of file, so that the -gnatl listing
 721          --  will be complete in this situation, but no error checking
 722          --  other than that provided at the token level.
 723
 724          while Token /= Tok_EOF loop
 725             Scan;
 726          end loop;
 727
 728          return Error;
 729
 730       --  Normal return (we were at the end of file as expected)
 731
 732       else
 733          return Comp_Unit_Node;
 734       end if;
 735
 736    exception
 737
 738       --  An error resync is a serious bomb, so indicate result unit no good
 739
 740       when Error_Resync =>
 741          Set_Fatal_Error (Current_Source_Unit);
 742          return Error;
 743    end P_Compilation_Unit;
 744
 745    --------------------------
 746    -- 10.1.1  Library Item --
 747    --------------------------
 748
 749    --  Parsed by P_Compilation_Unit (10.1.1)
 750
 751    --------------------------------------
 752    -- 10.1.1  Library Unit Declaration --
 753    --------------------------------------
 754
 755    --  Parsed by P_Compilation_Unit (10.1.1)
 756
 757    ------------------------------------------------
 758    -- 10.1.1  Library Unit Renaming Declaration  --
 759    ------------------------------------------------
 760
 761    --  Parsed by P_Compilation_Unit (10.1.1)
 762
 763    -------------------------------
 764    -- 10.1.1  Library Unit Body --
 765    -------------------------------
 766
 767    --  Parsed by P_Compilation_Unit (10.1.1)
 768
 769    ------------------------------
 770    -- 10.1.1  Parent Unit Name --
 771    ------------------------------
 772
 773    --  Parsed (as a name) by its parent construct
 774
 775    ----------------------------
 776    -- 10.1.2  Context Clause --
 777    ----------------------------
 778
 779    --  CONTEXT_CLAUSE ::= {CONTEXT_ITEM}
 780
 781    --  CONTEXT_ITEM ::= WITH_CLAUSE | USE_CLAUSE | WITH_TYPE_CLAUSE
 782
 783    --  WITH_CLAUSE ::=
 784    --  [LIMITED] [PRIVATE]  with library_unit_NAME {,library_unit_NAME};
 785    --  Note: the two qualifiers are Ada 2005 extensions.
 786
 787    --  WITH_TYPE_CLAUSE ::=
 788    --    with type type_NAME is access; | with type type_NAME is tagged;
 789    --  Note: this form is obsolete (old GNAT extension).
 790
 791    --  Error recovery: Cannot raise Error_Resync
 792
 793    function P_Context_Clause return List_Id is
 794       Item_List   : List_Id;
 795       Has_Limited : Boolean := False;
 796       Has_Private : Boolean := False;
 797       Scan_State  : Saved_Scan_State;
 798       With_Node   : Node_Id;
 799       First_Flag  : Boolean;
 800
 801    begin
 802       Item_List := New_List;
 803
 804       --  Get keyword casing from WITH keyword in case not set yet
 805
 806       if Token = Tok_With then
 807          Set_Keyword_Casing (Current_Source_File, Determine_Token_Casing);
 808       end if;
 809
 810       --  Loop through context items
 811
 812       loop
 813          if Style_Check then
 814             Style.Check_Indentation;
 815          end if;
 816
 817          --  Gather any pragmas appearing in the context clause
 818
 819          P_Pragmas_Opt (Item_List);
 820
 821          --  Processing for WITH clause
 822
 823          --  Ada 2005 (AI-50217, AI-262): First check for LIMITED WITH,
 824          --  PRIVATE WITH, or both.
 825
 826          if Token = Tok_Limited then
 827             Has_Limited := True;
 828             Has_Private := False;
 829             Scan; -- past LIMITED
 830
 831             --  In the context, LIMITED can only appear in a with_clause
 832
 833             if Token = Tok_Private then
 834                Has_Private := True;
 835                Scan;  -- past PRIVATE
 836             end if;
 837
 838             if Token /= Tok_With then
 839                Error_Msg_SC ("unexpected LIMITED ignored");
 840             end if;
 841
 842             if Ada_Version < Ada_05 then
 843                Error_Msg_SP ("LIMITED WITH is an Ada 2005 extension");
 844                Error_Msg_SP
 845                  ("\unit must be compiled with -gnat05 switch");
 846             end if;
 847
 848          elsif Token = Tok_Private then
 849             Has_Limited := False;
 850             Has_Private := True;
 851             Save_Scan_State (Scan_State);
 852             Scan;  -- past PRIVATE
 853
 854             if Token /= Tok_With then
 855
 856                --  Keyword is beginning of private child unit
 857
 858                Restore_Scan_State (Scan_State); -- to PRIVATE
 859                return Item_List;
 860
 861             elsif Ada_Version < Ada_05 then
 862                Error_Msg_SP ("`PRIVATE WITH` is an Ada 2005 extension");
 863                Error_Msg_SP
 864                  ("\unit must be compiled with -gnat05 switch");
 865             end if;
 866
 867          else
 868             Has_Limited := False;
 869             Has_Private := False;
 870          end if;
 871
 872          if Token = Tok_With then
 873             Scan; -- past WITH
 874
 875             if Token = Tok_Type then
 876
 877                --  WITH TYPE is an obsolete GNAT specific extension
 878
 879                Error_Msg_SP
 880                  ("`WITH TYPE` is an obsolete 'G'N'A'T extension");
 881                Error_Msg_SP ("\use Ada 2005 `LIMITED WITH` clause instead");
 882
 883                Scan;  -- past TYPE
 884
 885                T_Is;
 886
 887                if Token = Tok_Tagged then
 888                   Scan;
 889
 890                elsif Token = Tok_Access then
 891                   Scan;
 892
 893                else
 894                   Error_Msg_SC ("expect tagged or access qualifier");
 895                end if;
 896
 897                TF_Semicolon;
 898
 899             else
 900                First_Flag := True;
 901
 902                --  Loop through names in one with clause, generating a separate
 903                --  N_With_Clause node for each name encountered.
 904
 905                loop
 906                   With_Node := New_Node (N_With_Clause, Token_Ptr);
 907                   Append (With_Node, Item_List);
 908
 909                   --  Note that we allow with'ing of child units, even in
 910                   --  Ada 83 mode, since presumably if this is not desired,
 911                   --  then the compilation of the child unit itself is the
 912                   --  place where such an "error" should be caught.
 913
 914                   Set_Name (With_Node, P_Qualified_Simple_Name);
 915                   Set_First_Name (With_Node, First_Flag);
 916                   Set_Limited_Present (With_Node, Has_Limited);
 917                   Set_Private_Present (With_Node, Has_Private);
 918                   First_Flag := False;
 919
 920                   --  All done if no comma
 921
 922                   exit when Token /= Tok_Comma;
 923
 924                   --  If comma is followed by compilation unit token
 925                   --  or by USE, or PRAGMA, then it should have been a
 926                   --  semicolon after all
 927
 928                   Save_Scan_State (Scan_State);
 929                   Scan; -- past comma
 930
 931                   if Token in Token_Class_Cunit
 932                     or else Token = Tok_Use
 933                     or else Token = Tok_Pragma
 934                   then
 935                      Restore_Scan_State (Scan_State);
 936                      exit;
 937                   end if;
 938                end loop;
 939
 940                Set_Last_Name (With_Node, True);
 941                TF_Semicolon;
 942             end if;
 943
 944          --  Processing for USE clause
 945
 946          elsif Token = Tok_Use then
 947             Append (P_Use_Clause, Item_List);
 948
 949          --  Anything else is end of context clause
 950
 951          else
 952             exit;
 953          end if;
 954       end loop;
 955
 956       return Item_List;
 957    end P_Context_Clause;
 958
 959    --------------------------
 960    -- 10.1.2  Context Item --
 961    --------------------------
 962
 963    --  Parsed by P_Context_Clause (10.1.2)
 964
 965    -------------------------
 966    -- 10.1.2  With Clause --
 967    -------------------------
 968
 969    --  Parsed by P_Context_Clause (10.1.2)
 970
 971    -----------------------
 972    -- 10.1.3  Body Stub --
 973    -----------------------
 974
 975    --  Subprogram stub parsed by P_Subprogram (6.1)
 976    --  Package stub parsed by P_Package (7.1)
 977    --  Task stub parsed by P_Task (9.1)
 978    --  Protected stub parsed by P_Protected (9.4)
 979
 980    ----------------------------------
 981    -- 10.1.3  Subprogram Body Stub --
 982    ----------------------------------
 983
 984    --  Parsed by P_Subprogram (6.1)
 985
 986    -------------------------------
 987    -- 10.1.3  Package Body Stub --
 988    -------------------------------
 989
 990    --  Parsed by P_Package (7.1)
 991
 992    ----------------------------
 993    -- 10.1.3  Task Body Stub --
 994    ----------------------------
 995
 996    --  Parsed by P_Task (9.1)
 997
 998    ---------------------------------
 999    -- 10.1.3  Protected Body Stub --
1000    ---------------------------------
1001
1002    --  Parsed by P_Protected (9.4)
1003
1004    ---------------------
1005    -- 10.1.3  Subunit --
1006    ---------------------
1007
1008    --  SUBUNIT ::= separate (PARENT_UNIT_NAME) PROPER_BODY
1009
1010    --  PARENT_UNIT_NAME ::= NAME
1011
1012    --  The caller has checked that the initial token is SEPARATE
1013
1014    --  Error recovery: cannot raise Error_Resync
1015
1016    function P_Subunit return Node_Id is
1017       Subunit_Node : Node_Id;
1018       Body_Node    : Node_Id;
1019
1020    begin
1021       Subunit_Node := New_Node (N_Subunit, Token_Ptr);
1022       Body_Node := Error; -- in case no good body found
1023       Scan; -- past SEPARATE;
1024
1025       U_Left_Paren;
1026       Set_Name (Subunit_Node, P_Qualified_Simple_Name);
1027       U_Right_Paren;
1028
1029       Ignore (Tok_Semicolon);
1030
1031       if Token = Tok_Function or else Token = Tok_Procedure then
1032          Body_Node := P_Subprogram (Pf_Pbod);
1033
1034       elsif Token = Tok_Package then
1035          Body_Node := P_Package (Pf_Pbod);
1036
1037       elsif Token = Tok_Protected then
1038          Scan; -- past PROTECTED
1039
1040          if Token = Tok_Body then
1041             Body_Node := P_Protected;
1042          else
1043             Error_Msg_AP ("BODY expected");
1044             return Error;
1045          end if;
1046
1047       elsif Token = Tok_Task then
1048          Scan; -- past TASK
1049
1050          if Token = Tok_Body then
1051             Body_Node := P_Task;
1052          else
1053             Error_Msg_AP ("BODY expected");
1054             return Error;
1055          end if;
1056
1057       else
1058          Error_Msg_SC ("proper body expected");
1059          return Error;
1060       end if;
1061
1062       Set_Proper_Body  (Subunit_Node, Body_Node);
1063       return Subunit_Node;
1064    end P_Subunit;
1065
1066    ------------------
1067    -- Set_Location --
1068    ------------------
1069
1070    function Set_Location return Source_Ptr is
1071       Physical   : Boolean;
1072       Loc        : Source_Ptr;
1073       Scan_State : Saved_Scan_State;
1074
1075    begin
1076       --  A special check. If the first token is pragma, and this is a
1077       --  Source_Reference pragma, then do NOT eat previous comments, since
1078       --  the Source_Reference pragma is required to be the first line in
1079       --  the source file.
1080
1081       if Token = Tok_Pragma then
1082          Save_Scan_State (Scan_State);
1083          Scan; --  past Pragma
1084
1085          if Token = Tok_Identifier
1086            and then Token_Name = Name_Source_Reference
1087          then
1088             Restore_Scan_State (Scan_State);
1089             return Token_Ptr;
1090          end if;
1091
1092          Restore_Scan_State (Scan_State);
1093       end if;
1094
1095       --  Otherwise acquire previous comments and blank lines
1096
1097       if Prev_Token = No_Token then
1098          return Source_First (Current_Source_File);
1099
1100       else
1101          Loc := Prev_Token_Ptr;
1102          loop
1103             exit when Loc = Token_Ptr;
1104
1105             --  Should we worry about UTF_32 line terminators here
1106
1107             if Source (Loc) in Line_Terminator then
1108                Skip_Line_Terminators (Loc, Physical);
1109                exit when Physical;
1110             end if;
1111
1112             Loc := Loc + 1;
1113          end loop;
1114
1115          return Loc;
1116       end if;
1117    end Set_Location;
1118
1119    ------------------
1120    -- Unit_Display --
1121    ------------------
1122
1123    --  The format of the generated line, as expected by GNATCHOP is
1124
1125    --    Unit {unit} line {line}, file offset {offs} [, SR], file name {file}
1126
1127    --  where
1128
1129    --     {unit}     unit name with terminating (spec) or (body)
1130    --     {line}     starting line number
1131    --     {offs}     offset to start of text in file
1132    --     {file}     source file name
1133
1134    --  The SR parameter is present only if a source reference pragma was
1135    --  scanned for this unit. The significance is that gnatchop should not
1136    --  attempt to add another one.
1137
1138    procedure Unit_Display
1139      (Cunit      : Node_Id;
1140       Loc        : Source_Ptr;
1141       SR_Present : Boolean)
1142    is
1143       Unum : constant Unit_Number_Type    := Get_Cunit_Unit_Number (Cunit);
1144       Sind : constant Source_File_Index   := Source_Index (Unum);
1145       Unam : constant Unit_Name_Type      := Unit_Name (Unum);
1146
1147    begin
1148       if List_Units then
1149          Write_Str ("Unit ");
1150          Write_Unit_Name (Unit_Name (Unum));
1151          Unit_Location (Sind, Loc);
1152
1153          if SR_Present then
1154             Write_Str (", SR");
1155          end if;
1156
1157          Write_Str (", file name ");
1158          Write_Name (Get_File_Name (Unam, Nkind (Unit (Cunit)) = N_Subunit));
1159          Write_Eol;
1160       end if;
1161    end Unit_Display;
1162
1163    -------------------
1164    -- Unit_Location --
1165    -------------------
1166
1167    procedure Unit_Location (Sind : Source_File_Index; Loc : Source_Ptr) is
1168       Line : constant Logical_Line_Number := Get_Logical_Line_Number (Loc);
1169       --  Should the above be the physical line number ???
1170
1171    begin
1172       Write_Str (" line ");
1173       Write_Int (Int (Line));
1174
1175       Write_Str (", file offset ");
1176       Write_Int (Int (Loc) - Int (Source_First (Sind)));
1177    end Unit_Location;
1178
1179 end Ch10;