gcc/ada/opt.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                  O P T                                   --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                            $Revision: 1.4 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2001, Free Software Foundation, Inc.         --
  12 --                                                                          --
  13 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This package contains global switches set by the initialization
  37 --  routine from the command line and referenced throughout the compiler,
  38 --  the binder or gnatmake. The comments indicate which options are used by
  39 --  which programs (GNAT, GNATBIND, GNATMAKE).
  40
  41 with Hostparm;       use Hostparm;
  42 with Types;          use Types;
  43 with System.WCh_Con; use System.WCh_Con;
  44
  45 package Opt is
  46
  47    ----------------------------------------------
  48    -- Settings of Modes for Current Processing --
  49    ----------------------------------------------
  50
  51    --  The following mode values represent the current state of processing.
  52    --  The values set here are the default values. Unless otherwise noted,
  53    --  the value may be reset in Switch with an appropropiate switch. In
  54    --  some cases, the values can also be modified by pragmas, and in the
  55    --  case of some binder variables, Gnatbind.Scan_Bind_Arg may modify
  56    --  the default values.
  57
  58    Ada_Bind_File : Boolean := True;
  59    --  GNATBIND
  60    --  Set True if binder file to be generated in Ada rather than C
  61
  62    Ada_95 : Boolean := True;
  63    --  GNAT
  64    --  Set True if operating in Ada 95 mode
  65    --  Set False if operating in Ada 83 mode
  66
  67    Ada_83 : Boolean := False;
  68    --  GNAT
  69    --  Set True if operating in Ada 83 mode
  70    --  Set False if operating in Ada 95 mode
  71
  72    Ada_Final_Suffix : constant String := "final";
  73    --  GNATBIND
  74    --  The suffix of the name of the finalization procedure. This variable
  75    --  may be modified by Gnatbind.Scan_Bind_Arg.
  76
  77    Ada_Final_Name : String_Ptr := new String'("ada" & Ada_Final_Suffix);
  78    --  GNATBIND
  79    --  The name of the procedure that performs the finalization at the end of
  80    --  execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.
  81
  82    Ada_Init_Suffix : constant String := "init";
  83    --  GNATBIND
  84    --  The suffix of the name of the initialization procedure. This variable
  85    --  may be modified by Gnatbind.Scan_Bind_Arg.
  86
  87    Ada_Init_Name : String_Ptr := new String'("ada" & Ada_Init_Suffix);
  88    --  GNATBIND
  89    --  The name of the procedure that performs initialization at the start
  90    --  of execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.
  91
  92    Ada_Main_Name_Suffix : constant String := "main";
  93    --  GNATBIND
  94    --  The suffix for Ada_Main_Name. Defined as a constant here so that it
  95    --  can be referenced in a uniform manner to create either the default
  96    --  value of Ada_Main_Name (declared below), or the non-default name
  97    --  set by Gnatbind.Scan_Bind_Arg.
  98
  99    Ada_Main_Name : String_Ptr := new String'("ada_" & Ada_Main_Name_Suffix);
 100    --  GNATBIND
 101    --  The name of the Ada package generated by the binder (when in Ada mode).
 102    --  This variable may be modified by Gnatbind.Scan_Bind_Arg.
 103
 104    Address_Clause_Overlay_Warnings : Boolean := True;
 105    --  GNAT
 106    --  Set False to disable address clause warnings
 107
 108    All_Errors_Mode : Boolean := False;
 109    --  GNAT
 110    --  Flag set to force display of multiple errors on a single line and
 111    --  also repeated error messages for references to undefined identifiers
 112    --  and certain other repeated error messages.
 113
 114    All_Sources : Boolean := False;
 115    --  GNATBIND
 116    --  Set to True to require all source files to be present. This flag is
 117    --  directly modified by gnatmake to affect the shared binder routines.
 118
 119    Alternate_Main_Name : String_Ptr := null;
 120    --  Set to non null when Bind_Alternate_Main_Name is True. This value
 121    --  is modified as needed by Gnatbind.Scan_Bind_Arg.
 122
 123    Assertions_Enabled : Boolean := False;
 124    --  GNAT
 125    --  Enable assertions made using pragma Assert.
 126
 127    Back_Annotate_Rep_Info : Boolean := False;
 128    --  GNAT
 129    --  If set True (by use of -gnatB), enables back annotation of
 130    --  representation information by gigi, even in -gnatc mode.
 131
 132    Bind_Alternate_Main_Name : Boolean := False;
 133    --  GNATBIND
 134    --  Set to True if main should be called Alternate_Main_Name.all. This
 135    --  variable may be set to True by Gnatbind.Scan_Bind_Arg.
 136
 137    Bind_Main_Program : Boolean := True;
 138    --  GNATBIND
 139    --  Set to False if not binding main Ada program.
 140
 141    Bind_For_Library : Boolean := False;
 142    --  GNATBIND
 143    --  Set to True if the binder needs to generate a file designed for
 144    --  building a library. May be set to True by Gnatbind.Scan_Bind_Arg.
 145
 146    Bind_Only : Boolean := False;
 147    --  GNATMAKE
 148    --  Set to True to skip compile and link steps
 149    --  (except when Compile_Only and/or Link_Only are True).
 150
 151    Brief_Output : Boolean := False;
 152    --  GNAT, GNATBIND
 153    --  Force brief error messages to standard error, even if verbose mode is
 154    --  set (so that main error messages go to standard output).
 155
 156    Check_Object_Consistency : Boolean := False;
 157    --  GNATBIND, GNATMAKE
 158    --  Set to True to check whether every object file is consistent with
 159    --  with its corresponding ada library information (ali) file. An object
 160    --  file is inconsistent with the corresponding ali file if the object
 161    --  file does not exist or if it has an older time stamp than the ali file.
 162    --  Default above is for GNATBIND. GNATMAKE overrides this default to
 163    --  True (see Make.Initialize) since we do not need to check source
 164    --  consistencies in gnatmake in this sense.
 165
 166    Check_Only : Boolean := False;
 167    --  GNATBIND
 168    --  Set to True to do checks only, no output of binder file.
 169
 170    Check_Readonly_Files : Boolean := False;
 171    --  GNATMAKE
 172    --  Set to True to check readonly files during the make process.
 173
 174    Check_Source_Files : Boolean := True;
 175    --  GNATBIND
 176    --  Set to True to enable consistency checking for any source files that
 177    --  are present (i.e. date must match the date in the library info file).
 178    --  Set to False for object file consistency check only. This flag is
 179    --  directly modified by gnatmake, to affect the shared binder routines.
 180
 181    Check_Switches : Boolean := False;
 182    --  GNATMAKE
 183    --  Set to True to check compiler options during the make process.
 184
 185    Check_Unreferenced : Boolean := False;
 186    --  GNAT
 187    --  Set to True to enable checking for unreferenced variables
 188
 189    Check_Withs : Boolean := False;
 190    --  GNAT
 191    --  Set to True to enable checking for unused withs, and also the case
 192    --  of withing a package and using none of the entities in the package.
 193
 194    Compile_Only : Boolean := False;
 195    --  GNATMAKE
 196    --  Set to True to skip bind and link steps (except when Bind_Only is True)
 197
 198    Compress_Debug_Names : Boolean := False;
 199    --  GNATMAKE
 200    --  Set to True if the option to compress debug information is set (-gnatC)
 201
 202    Config_File : Boolean := True;
 203    --  GNAT
 204    --  Set to False to inhibit reading and processing of gnat.adc file
 205
 206    Config_File_Name : String_Ptr := null;
 207    --  GNAT
 208    --  File name of configuration pragmas file (given by switch -gnatec)
 209
 210    Constant_Condition_Warnings : Boolean := False;
 211    --  GNAT
 212    --  Set to True to activate warnings on constant conditions
 213
 214    subtype Debug_Level_Value is Nat range 0 .. 3;
 215    Debugger_Level : Debug_Level_Value := 0;
 216    --  GNATBIND
 217    --  The value given to the -g parameter.
 218    --  The default value for -g with no value is 2
 219    --  This is usually ignored by GNATBIND, except in the VMS version
 220    --  where it is passed as an argument to __gnat_initialize to trigger
 221    --  the activation of the remote debugging interface (is this true???).
 222
 223    Debug_Generated_Code : Boolean := False;
 224    --  GNAT
 225    --  Set True (-gnatD switch) to debug generated expanded code instead
 226    --  of the original source code. Causes debugging information to be
 227    --  written with respect to the generated code file that is written.
 228
 229    Display_Compilation_Progress : Boolean := False;
 230    --  GNATMAKE
 231    --  Set True (-d switch) to display information on progress while compiling
 232    --  files. Internal switch to be used in conjunction with an IDE such as
 233    --  Glide.
 234
 235    type Distribution_Stub_Mode_Type is
 236    --  GNAT
 237      (No_Stubs,
 238       --  Normal mode, no generation/compilation of distribution stubs
 239
 240       Generate_Receiver_Stub_Body,
 241       --  The unit being compiled is the RCI body, and the compiler will
 242       --  generate the body for the receiver stubs and compile it.
 243
 244       Generate_Caller_Stub_Body);
 245       --  The unit being compiled is the RCI spec, and the compiler will
 246       --  generate the body for the caller stubs and compile it.
 247
 248    Distribution_Stub_Mode : Distribution_Stub_Mode_Type := No_Stubs;
 249    --  GNAT
 250    --  This enumeration variable indicates the five states of distribution
 251    --  annex stub generation/compilation.
 252
 253    Do_Not_Execute : Boolean := False;
 254    --  GNATMAKE
 255    --  Set to True if no actual compilations should be undertaken.
 256
 257    Dynamic_Elaboration_Checks : Boolean := False;
 258    --  GNAT
 259    --  Set True for dynamic elaboration checking mode, as set by the -gnatE
 260    --  switch or by the use of pragma Elaboration_Checks (Dynamic).
 261
 262    Elab_Dependency_Output : Boolean := False;
 263    --  GNATBIND
 264    --  Set to True to output complete list of elaboration constraints
 265
 266    Elab_Order_Output : Boolean := False;
 267    --  GNATBIND
 268    --  Set to True to output chosen elaboration order
 269
 270    Elab_Warnings : Boolean := False;
 271    --  GNAT
 272    --  Set to True to generate full elaboration warnings (-gnatwl)
 273
 274    type Exception_Mechanism_Type is (Setjmp_Longjmp, Front_End_ZCX, GCC_ZCX);
 275    Exception_Mechanism : Exception_Mechanism_Type := Setjmp_Longjmp;
 276    --  GNAT
 277    --  Set to the appropriate value depending on the default as given in
 278    --  system.ads (ZCX_By_Default, GCC_ZCX_Support, Front_End_ZCX_Support)
 279    --  and the use of -gnatL -gnatZ (and -gnatdX)
 280
 281    Exception_Tracebacks : Boolean := False;
 282    --  GNATBIND
 283    --  Set to True to store tracebacks in exception occurrences (-E)
 284
 285    Extensions_Allowed : Boolean := False;
 286    --  GNAT
 287
 288    type External_Casing_Type is (
 289      As_Is,       -- External names cased as they appear in the Ada source
 290      Uppercase,   -- External names forced to all uppercase letters
 291      Lowercase);  -- External names forced to all lowercase letters
 292
 293    External_Name_Imp_Casing : External_Casing_Type := Lowercase;
 294    --  The setting of this switch determines the casing of external names
 295    --  when the name is implicitly derived from an entity name (i.e. either
 296    --  no explicit External_Name or Link_Name argument is used, or, in the
 297    --  case of extended DEC pragmas, the external name is given using an
 298    --  identifier. The As_Is setting is not permitted here (since this would
 299    --  create Ada source programs that were case sensitive).
 300
 301    External_Name_Exp_Casing : External_Casing_Type := As_Is;
 302    --  The setting of this switch determines the casing of an external name
 303    --  specified explicitly with a string literal. As_Is means the string
 304    --  literal is used as given with no modification to the casing. If
 305    --  Lowercase or Uppercase is set, then the string is forced to all
 306    --  lowercase or all uppercase letters as appropriate. Note that this
 307    --  setting has no effect if the external name is given using an identifier
 308    --  in the case of extended DEC import/export pragmas (in this case the
 309    --  casing is controlled by External_Name_Imp_Casing), and also has no
 310    --  effect if an explicit Link_Name is supplied (a link name is always
 311    --  used exactly as given).
 312
 313    Float_Format : Character := ' ';
 314    --  GNAT
 315    --  A non-blank value indicates that a Float_Format pragma has been
 316    --  processed, in which case this variable is set to 'I' for IEEE or
 317    --  to 'V' for VAX. The setting of 'V' is only possible on OpenVMS
 318    --  versions of GNAT.
 319
 320    Float_Format_Long : Character := ' ';
 321    --  GNAT
 322    --  A non-blank value indicates that a Long_Float pragma has been
 323    --  processed (this pragma is recognized only in OpenVMS versions
 324    --  of GNAT), in which case this variable is set to D or G for
 325    --  D_Float or G_Float.
 326
 327    Force_ALI_Tree_File : Boolean := False;
 328    --  GNAT
 329    --  Force generation of ali file even if errors are encountered.
 330    --  Also forces generation of tree file if -gnatt is also set.
 331
 332    Force_Compilations : Boolean := False;
 333    --  GNATMAKE
 334    --  Set to force recompilations even when the objects are up-to-date.
 335
 336    Force_RM_Elaboration_Order : Boolean := False;
 337    --  GNATBIND
 338    --  True if binding with forced RM elaboration order (-f switch set)
 339    --  Note: this is considered an obsolescent option, to be removed in
 340    --  some future release. it is no longer documented. The proper way
 341    --  to get this effect is to use -gnatE and suppress elab checks.
 342
 343    Full_List : Boolean := False;
 344    --  GNAT
 345    --  Set True to generate full source listing with embedded errors
 346
 347    Global_Discard_Names : Boolean := False;
 348    --  GNAT
 349    --  Set true if a pragma Discard_Names applies to the current unit
 350
 351    GNAT_Mode : Boolean := False;
 352    --  GNAT
 353    --  True if compiling in GNAT system mode (-g switch set)
 354
 355    HLO_Active : Boolean := False;
 356    --  GNAT
 357    --  True if High Level Optimizer is activated
 358
 359    Implementation_Unit_Warnings : Boolean := True;
 360    --  GNAT
 361    --  Set True to active warnings for use of implementation internal units.
 362    --  Can be controlled by use of -gnatwi/-gnatwI.
 363
 364    Identifier_Character_Set : Character;
 365    --  GNAT
 366    --  This variable indicates the character set to be used for identifiers.
 367    --  The possible settings are:
 368    --    '1'  Latin-1
 369    --    '2'  Latin-2
 370    --    '3'  Latin-3
 371    --    '4'  Latin-4
 372    --    'p'  PC (US, IBM page 437)
 373    --    '8'  PC (European, IBM page 850)
 374    --    'f'  Full upper set (all distinct)
 375    --    'n'  No upper characters (Ada/83 rules)
 376    --    'w'  Latin-1 plus wide characters allowed in identifiers
 377    --
 378    --  The setting affects the set of letters allowed in identifiers and the
 379    --  upper/lower case equivalences. It does not affect the interpretation of
 380    --  character and string literals, which are always stored using the actual
 381    --  coding in the source program. This variable is initialized to the
 382    --  default value appropriate to the system (in Osint.Initialize), and then
 383    --  reset if a command line switch is used to change the setting.
 384
 385    Ineffective_Inline_Warnings : Boolean := False;
 386    --  GNAT
 387    --  Set True to activate warnings if front-end inlining (-gnatN) is not
 388    --  able to actually inline a particular call (or all calls). Can be
 389    --  controlled by use of -gnatwp/-gnatwP.
 390
 391    Init_Or_Norm_Scalars : Boolean := False;
 392    --  GNAT
 393    --  Set True if a pragma Initialize_Scalars applies to the current unit.
 394    --  Also set True if a pragma Normalize_Scalars applies.
 395
 396    Initialize_Scalars : Boolean := False;
 397    --  GNAT
 398    --  Set True if a pragma Initialize_Scalars applies to the current unit.
 399    --  Note that Init_Or_Norm_Scalars is also set to True if this is True.
 400
 401    Initialize_Scalars_Mode : Character := 'I';
 402    --  GNATBIND
 403    --  Set to 'I' for -Sin (default), 'L' for -Slo, 'H' for -Shi, 'X' for -Sxx
 404
 405    Initialize_Scalars_Val : String (1 .. 2);
 406    --  GNATBIND
 407    --  Valid only if Initialize_Scalars_Mode is set to 'X' (-Shh). Contains
 408    --  the two hex bytes from the -Shh switch.
 409
 410    Inline_Active : Boolean := False;
 411    --  GNAT
 412    --  Set True to activate pragma Inline processing across modules. Default
 413    --  for now is not to inline across module boundaries.
 414
 415    Front_End_Inlining : Boolean := False;
 416    --  GNAT
 417    --  Set True to activate inlining by front-end expansion.
 418
 419    Inline_Processing_Required : Boolean := False;
 420    --  GNAT
 421    --  Set True if inline processing is required. Inline processing is
 422    --  required if an active Inline pragma is processed. The flag is set
 423    --  for a pragma Inline or Inline_Always that is actually active.
 424
 425    In_Place_Mode : Boolean := False;
 426    --  GNATMAKE
 427    --  Set True to store ALI and object files in place ie in the object
 428    --  directory if these files already exist or in the source directory
 429    --  if not.
 430
 431    Keep_Going : Boolean := False;
 432    --  GNATMAKE
 433    --  When True signals gnatmake to ignore compilation errors and keep
 434    --  processing sources until there is no more work.
 435
 436    Link_Only : Boolean := False;
 437    --  GNATMAKE
 438    --  Set to True to skip compile and bind steps
 439    --  (except when Bind_Only is set to True).
 440
 441    List_Units : Boolean := False;
 442    --  GNAT
 443    --  List units in the active library
 444
 445    List_Dependencies : Boolean := False;
 446    --  GNATMAKE
 447    --  When True gnatmake verifies that the objects are up to date and
 448    --  outputs the list of object dependencies. This list can be used
 449    --  directly in a Makefile.
 450
 451    List_Representation_Info : Int range 0 .. 3 := 0;
 452    --  GNAT
 453    --  Set true by -gnatR switch to list representation information.
 454    --  The settings are as follows:
 455    --
 456    --    0 = no listing of representation information (default as above)
 457    --    1 = list rep info for user defined record and array types
 458    --    2 = list rep info for all user defined types and objects
 459    --    3 = like 2, but variable fields are decoded symbolically
 460
 461    Locking_Policy : Character := ' ';
 462    --  GNAT
 463    --  Set to ' ' for the default case (no locking policy specified).
 464    --  Reset to first character (uppercase) of locking policy name if a
 465    --  valid pragma Locking_Policy is encountered.
 466
 467    Look_In_Primary_Dir : Boolean := True;
 468    --  GNAT, GNATBIND, GNATMAKE
 469    --  Set to False if a -I- was present on the command line.
 470    --  When True we are allowed to look in the primary directory to locate
 471    --  other source or library files.
 472
 473    Mapping_File_Name : String_Ptr := null;
 474    --  GNAT
 475    --  File name of mapping between unit names, file names and path names.
 476    --  (given by switch -gnatem)
 477
 478    Maximum_Errors : Int := 9999;
 479    --  GNAT, GNATBIND
 480    --  Maximum number of errors before compilation is terminated
 481
 482    Maximum_File_Name_Length : Int;
 483    --  GNAT, GNATBIND
 484    --  Maximum number of characters allowed in a file name, not counting the
 485    --  extension, as set by the appropriate switch. If no switch is given,
 486    --  then this value is initialized by Osint to the appropriate value.
 487
 488    Maximum_Processes : Positive := 1;
 489    --  GNATMAKE
 490    --  Maximum number of processes that should be spawned to carry out
 491    --  compilations.
 492
 493    Minimal_Recompilation : Boolean := False;
 494    --  GNATMAKE
 495    --  Set to True if minimal recompilation mode requested.
 496
 497    No_Stdlib : Boolean := False;
 498    --  GNATMAKE
 499    --  Set to True if no default library search dirs added to search list.
 500
 501    No_Stdinc : Boolean := False;
 502    --  GNATMAKE
 503    --  Set to True if no default source search dirs added to search list.
 504
 505    No_Main_Subprogram : Boolean := False;
 506    --  GNATMAKE, GNATBIND
 507    --  Set to True if compilation/binding of a program without main
 508    --  subprogram requested.
 509
 510    Normalize_Scalars : Boolean := False;
 511    --  GNAT
 512    --  Set True if a pragma Normalize_Scalars applies to the current unit.
 513    --  Note that Init_Or_Norm_Scalars is also set to True if this is True.
 514
 515    No_Run_Time : Boolean := False;
 516    --  GNAT
 517    --  Set True if a valid pragma No_Run_Time is processed or if the
 518    --  flag Targparm.High_Integrity_Mode_On_Target is set True.
 519
 520    type Operating_Mode_Type is (Check_Syntax, Check_Semantics, Generate_Code);
 521    Operating_Mode : Operating_Mode_Type := Generate_Code;
 522    --  GNAT
 523    --  Indicates the operating mode of the compiler. The default is generate
 524    --  code, which runs the parser, semantics and backend. Switches can be
 525    --  used to set syntax checking only mode, or syntax and semantics checking
 526    --  only mode. Operating_Mode can also be modified as a result of detecting
 527    --  errors during the compilation process. In particular if any error is
 528    --  detected then this flag is reset from Generate_Code to Check_Semantics
 529    --  after generating an error message.
 530
 531    Output_File_Name_Present : Boolean := False;
 532    --  GNATBIND, GNAT
 533    --  Set to True when the output C file name is given with option -o
 534    --  for GNATBIND or when the object file name is given with option
 535    --  -gnatO for GNAT.
 536
 537    Output_Linker_Option_List : Boolean := False;
 538    --  GNATBIND
 539    --  True if output of list of linker options is requested (-K switch set)
 540
 541    Output_Object_List : Boolean := False;
 542    --  GNATBIND
 543    --  True if output of list of objects is requested (-O switch set)
 544
 545    Pessimistic_Elab_Order : Boolean := False;
 546    --  GNATBIND
 547    --  True if pessimistic elaboration order is to be chosen (-p switch set)
 548
 549    Polling_Required : Boolean := False;
 550    --  GNAT
 551    --  Set to True if polling for asynchronous abort is enabled by using
 552    --  the -gnatP option for GNAT.
 553
 554    Print_Generated_Code : Boolean := False;
 555    --  GNAT
 556    --  Set to True to enable output of generated code in source form. This
 557    --  flag is set by the -gnatG switch.
 558
 559    Propagate_Exceptions : Boolean := False;
 560    --  GNAT
 561    --  Indicates if subprogram descriptor exception tables should be
 562    --  built for imported subprograms. Set True if a Propagate_Exceptions
 563    --  pragma applies to the extended main unit.
 564
 565    Queuing_Policy : Character := ' ';
 566    --  GNAT
 567    --  Set to ' ' for the default case (no queuing policy specified). Reset to
 568    --  Reset to first character (uppercase) of locking policy name if a valid
 569    --  Queuing_Policy pragma is encountered.
 570
 571    Quiet_Output : Boolean := False;
 572    --  GNATMAKE
 573    --  Set to True if the list of compilation commands should not be output.
 574
 575    Shared_Libgnat : Boolean;
 576    --  GNATBIND
 577    --  Set to True if a shared libgnat is requested by using the -shared
 578    --  option for GNATBIND and to False when using the -static option. The
 579    --  value of this switch is set by Gnatbind.Scan_Bind_Arg.
 580
 581    Software_Overflow_Checking : Boolean;
 582    --  GNAT
 583    --  Set to True by Osint.Initialize if the target requires the software
 584    --  approach to integer arithmetic overflow checking (i.e. the use of
 585    --  double length arithmetic followed by a range check). Set to False
 586    --  if the target implements hardware overflow checking.
 587
 588    Stack_Checking_Enabled : Boolean;
 589    --  GNAT
 590    --  Set to indicate if -fstack-check switch is set for the compilation.
 591    --  True means that the switch is set, so that stack checking is enabled.
 592    --  False means that the switch is not set (no stack checking). This
 593    --  value is obtained from the external imported value flag_stack_check
 594    --  in the gcc backend (see Frontend) and may be referenced throughout
 595    --  the compilation phases.
 596
 597    Strict_Math : aliased Boolean := False;
 598    --  GNAT
 599    --  This switch is set True if the current unit is to be compiled in
 600    --  strict math mode. The effect is to cause certain library file name
 601    --  substitutions to implement strict math semantics. See the routine
 602    --  Adjust_File_Name_For_Configuration, and also the configuration
 603    --  in the body of Opt.
 604    --
 605    --  Note: currently this switch is always False. Eventually it will be
 606    --  settable by a switch and a configuration pragma.
 607
 608    Style_Check : Boolean := False;
 609    --  GNAT
 610    --  Set True to perform style checks. Activates checks carried out
 611    --  in package Style (see body of this package for details of checks)
 612    --  This flag is set True by either the -gnatg or -gnaty switches.
 613
 614    System_Extend_Pragma_Arg : Node_Id := Empty;
 615    --  GNAT
 616    --  Set non-empty if and only if a correct Extend_System pragma was present
 617    --  in which case it points to the argument of the pragma, and the name can
 618    --  be located as Chars (Expression (System_Extend_Pragma_Arg)).
 619
 620    Subunits_Missing : Boolean := False;
 621    --  This flag is set true if missing subunits are detected with code
 622    --  generation active. This causes code generation to be skipped.
 623
 624    Suppress_Options : Suppress_Record;
 625    --  GNAT
 626    --  Flags set True to suppress corresponding check, i.e. add an implicit
 627    --  pragma Suppress at the outer level of each unit compiled. Note that
 628    --  these suppress actions can be overridden by the use of the Unsuppress
 629    --  pragma. This variable is initialized by Osint.Initialize.
 630
 631    Table_Factor : Int := 1;
 632    --  Factor by which all initial table sizes set in Alloc are multiplied.
 633    --  Used in Table to calculate initial table sizes (the initial table
 634    --  size is the value in Alloc, used as the Table_Initial parameter
 635    --  value, multiplied by the factor given here. The default value is
 636    --  used if no -gnatT switch appears.
 637
 638    Task_Dispatching_Policy : Character := ' ';
 639    --  GNAT
 640    --  Set to ' ' for the default case (no task dispatching policy specified).
 641    --  Reset to first character (uppercase) of task dispatching policy name
 642    --  if a valid Task_Dispatching_Policy pragma is encountered.
 643
 644    Tasking_Used : Boolean := False;
 645    --  Set True if any tasking construct is encountered. Used to activate the
 646    --  output of the Q, L and T lines in ali files.
 647
 648    Time_Slice_Set : Boolean := False;
 649    --  Set True if a pragma Time_Slice is processed in the main unit, or
 650    --  if the T switch is present to set a time slice value.
 651
 652    Time_Slice_Value : Nat;
 653    --  Time slice value. Valid only if Time_Slice_Set is True, i.e. if a
 654    --  Time_Slice pragma has been processed. Set to the time slice value
 655    --  in microseconds. Negative values are stored as zero, and the value
 656    --  is not larger than 1_000_000_000 (1000 seconds). Values larger than
 657    --  this are reset to this maximum.
 658
 659    Tolerate_Consistency_Errors : Boolean := False;
 660    --  GNATBIND
 661    --  Tolerate time stamp and other consistency errors. If this switch is
 662    --  set true, then inconsistencies result in warnings rather than errors.
 663
 664    Tree_Output : Boolean := False;
 665    --  GNAT
 666    --  Set True to generate output tree file
 667
 668    Try_Semantics : Boolean := False;
 669    --  GNAT
 670    --  Flag set to force attempt at semantic analysis, even if parser errors
 671    --  occur. This will probably cause blowups at this stage in the game. On
 672    --  the other hand, most such blowups will be caught cleanly and simply
 673    --  say compilation abandoned.
 674
 675    Unique_Error_Tag : Boolean := Tag_Errors;
 676    --  GNAT
 677    --  Indicates if error messages are to be prefixed by the string error:
 678    --  Initialized from Tag_Errors, can be forced on with the -gnatU switch.
 679
 680    Unreserve_All_Interrupts : Boolean := False;
 681    --  GNAT, GNATBIND
 682    --  Normally set False, set True if a valid Unreserve_All_Interrupts
 683    --  pragma appears anywhere in the main unit for GNAT, or if any ALI
 684    --  file has the corresponding attribute set in GNATBIND.
 685
 686    Upper_Half_Encoding : Boolean := False;
 687    --  GNAT
 688    --  Normally set False, indicating that upper half ASCII characters are
 689    --  used in the normal way to represent themselves. If the wide character
 690    --  encoding method uses the upper bit for this encoding, then this flag
 691    --  is set True, and upper half characters in the source indicate the
 692    --  start of a wide character sequence.
 693
 694    Usage_Requested : Boolean := False;
 695    --  GNAT, GNATBIND, GNATMAKE
 696    --  Set to True if h switch encountered requesting usage information
 697
 698    Use_VADS_Size : Boolean := False;
 699    --  GNAT
 700    --  Set to True if a valid pragma Use_VADS_Size is processed
 701
 702    Validity_Checks_On  : Boolean := True;
 703    --  This flag determines if validity checking is on or off. The initial
 704    --  state is on, and the required default validity checks are active. The
 705    --  actual set of checks that is performed if Validity_Checks_On is set
 706    --  is defined by the switches in package Sem_Val. The Validity_Checks_On
 707    --  switch is controlled by pragma Validity_Checks (On | Off), and also
 708    --  some generated compiler code (typically code that has to do with
 709    --  validity check generation) is compiled with this switch set to False.
 710
 711    Verbose_Mode : Boolean := False;
 712    --  GNAT, GNATBIND
 713    --  Set to True to get verbose mode (full error message text and location
 714    --  information sent to standard output, also header, copyright and summary)
 715
 716    Warn_On_Biased_Rounding : Boolean := False;
 717    --  GNAT
 718    --  Set to True to generate warnings for static constants that are rounded
 719    --  in a manner inconsistent with unbiased rounding (round to even). Can
 720    --  be modified by use of -gnatwb/B.
 721
 722    Warn_On_Hiding : Boolean := False;
 723    --  GNAT
 724    --  Set to True to generate warnings if a declared entity hides another
 725    --  entity. The default is that this warning is suppressed.
 726
 727    Warn_On_Redundant_Constructs : Boolean := False;
 728    --  GNAT
 729    --  Set to True to generate warnings for redundant constructs (e.g. useless
 730    --  assignments/conversions). The default is that this warning is disabled.
 731
 732    type Warning_Mode_Type is (Suppress, Normal, Treat_As_Error);
 733    Warning_Mode : Warning_Mode_Type := Normal;
 734    --  GNAT, GNATBIND
 735    --  Controls treatment of warning messages. If set to Suppress, warning
 736    --  messages are not generated at all. In Normal mode, they are generated
 737    --  but do not count as errors. In Treat_As_Error mode, warning messages
 738    --  are generated and are treated as errors.
 739
 740    Wide_Character_Encoding_Method : WC_Encoding_Method := WCEM_Brackets;
 741    --  GNAT
 742    --  Method used for encoding wide characters in the source program. See
 743    --  description of type in unit System.WCh_Con for a list of the methods
 744    --  that are currently supported. Note that brackets notation is always
 745    --  recognized in source programs regardless of the setting of this
 746    --  variable. The default setting causes only the brackets notation
 747    --  to be recognized. If this is the main unit, this setting also
 748    --  controls the output of the W=? parameter in the ali file, which
 749    --  is used to provide the default for Wide_Text_IO files.
 750
 751    Xref_Active : Boolean := True;
 752    --  GNAT
 753    --  Set if cross-referencing is enabled (i.e. xref info in ali files)
 754
 755    Zero_Cost_Exceptions_Val : Boolean;
 756    Zero_Cost_Exceptions_Set : Boolean := False;
 757    --  GNAT
 758    --  These values are to record the setting of the zero cost exception
 759    --  handling mode set by argument switches (-gnatZ/-gnatL). If the
 760    --  value is set by one of these switches, then Zero_Cost_Exceptions_Set
 761    --  is set to True, and Zero_Cost_Exceptions_Val indicates the setting.
 762    --  This value is used to reset ZCX_By_Default_On_Target.
 763
 764    ----------------------------
 765    -- Configuration Settings --
 766    ----------------------------
 767
 768    --  These are settings that are used to establish the mode at the start
 769    --  of each unit. The values defined below can be affected either by
 770    --  command line switches, or by the use of appropriate configuration
 771    --  pragmas in the gnat.adc file.
 772
 773    Ada_83_Config : Boolean;
 774    --  GNAT
 775    --  This is the value of the configuration switch for Ada 83 mode, as set
 776    --  by the command line switch -gnat83, and possibly modified by the use
 777    --  of configuration pragmas Ada_95 and Ada_83 in the gnat.adc file. This
 778    --  switch is used to set the initial value for Ada_83 mode at the start
 779    --  of analysis of a unit. Note however, that the setting of this switch
 780    --  is ignored for internal and predefined units (which are always compiled
 781    --  in Ada 95 mode).
 782
 783    Dynamic_Elaboration_Checks_Config : Boolean := False;
 784    --  GNAT
 785    --  Set True for dynamic elaboration checking mode, as set by the -gnatE
 786    --  switch or by the use of pragma Elaboration_Checking (Dynamic).
 787
 788    Extensions_Allowed_Config : Boolean;
 789    --  GNAT
 790    --  This is the switch that indicates whether extensions are allowed.
 791    --  It can be set True either by use of the -gnatX switch, or by use
 792    --  of the configuration pragma Extensions_Allowed (On). It is always
 793    --  set to True for internal GNAT units, since extensions are always
 794    --  permitted in such units.
 795
 796    External_Name_Exp_Casing_Config : External_Casing_Type;
 797    --  GNAT
 798    --  This is the value of the configuration switch that controls casing
 799    --  of external symbols for which an explicit external name is given. It
 800    --  can be set to Uppercase by the command line switch -gnatF, and further
 801    --  modified by the use of the configuration pragma External_Name_Casing
 802    --  in the gnat.adc file. This switch is used to set the initial value
 803    --  for External_Name_Exp_Casing at the start of analyzing each unit.
 804    --  Note however that the setting of this switch is ignored for internal
 805    --  and predefined units (which are always compiled with As_Is mode).
 806
 807    External_Name_Imp_Casing_Config : External_Casing_Type;
 808    --  GNAT
 809    --  This is the value of the configuration switch that controls casing
 810    --  of external symbols where the external name is implicitly given. It
 811    --  can be set to Uppercase by the command line switch -gnatF, and further
 812    --  modified by the use of the configuration pragma External_Name_Casing
 813    --  in the gnat.adc file. This switch is used to set the initial value
 814    --  for External_Name_Imp_Casing at the start of analyzing each unit.
 815    --  Note however that the setting of this switch is ignored for internal
 816    --  and predefined units (which are always compiled with Lowercase mode).
 817
 818    Polling_Required_Config : Boolean;
 819    --  GNAT
 820    --  This is the value of the configuration switch that controls polling
 821    --  mode. It can be set True by the command line switch -gnatP, and then
 822    --  further modified by the use of pragma Polling in the gnat.adc file.
 823    --  This switch is used to set the initial value for Polling_Required
 824    --  at the start of analyzing each unit.
 825
 826    Use_VADS_Size_Config : Boolean;
 827    --  GNAT
 828    --  This is the value of the configuration switch that controls the use
 829    --  of VADS_Size instead of Size whereever the attribute Size is used.
 830    --  It can be set True by the use of the pragma Use_VADS_Size in the
 831    --  gnat.adc file. This switch is used to set the initial value for
 832    --  Use_VADS_Size at the start of analyzing each unit. Note however that
 833    --  the setting of this switch is ignored for internal and predefined
 834    --  units (which are always compiled with the standard Size semantics).
 835
 836    type Config_Switches_Type is private;
 837    --  Type used to save values of the switches set from Config values
 838
 839    procedure Save_Opt_Config_Switches (Save : out Config_Switches_Type);
 840    --  This procedure saves the current values of the switches which are
 841    --  initialized from the above Config values, and then resets these
 842    --  switches according to the Config value settings.
 843
 844    procedure Set_Opt_Config_Switches (Internal_Unit : Boolean);
 845    --  This procedure sets the switches to the appropriate initial values.
 846    --  The parameter Internal_Unit is True for an internal or predefined
 847    --  unit, and affects the way the switches are set (see above).
 848
 849    procedure Restore_Opt_Config_Switches (Save : Config_Switches_Type);
 850    --  This procedure restores a set of switch values previously saved
 851    --  by a call to Save_Opt_Switches.
 852
 853    procedure Register_Opt_Config_Switches;
 854    --  This procedure is called after processing the gnat.adc file to record
 855    --  the values of the Config switches, as possibly modified by the use
 856    --  of command line switches and configuration pragmas.
 857
 858    ------------------------
 859    -- Other Global Flags --
 860    ------------------------
 861
 862    Expander_Active : Boolean := False;
 863    --  A flag that indicates if expansion is active (True) or deactivated
 864    --  (False). When expansion is deactivated all calls to expander routines
 865    --  have no effect. Note that the initial setting of False is merely to
 866    --  prevent saving of an undefined value for an initial call to the
 867    --  Expander_Mode_Save_And_Set procedure. For more information on the
 868    --  use of this flag, see package Expander. Indeed this flag might more
 869    --  logically be in the spec of Expander, but it is referenced by Errout,
 870    --  and it really seems wrong for Errout to depend on Expander.
 871
 872    -----------------------
 873    -- Tree I/O Routines --
 874    -----------------------
 875
 876    procedure Tree_Read;
 877    --  Reads switch settings from current tree file using Tree_Read
 878
 879    procedure Tree_Write;
 880    --  Writes out switch settings to current tree file using Tree_Write
 881
 882 private
 883
 884    type Config_Switches_Type is record
 885       Ada_83                     : Boolean;
 886       Dynamic_Elaboration_Checks : Boolean;
 887       Extensions_Allowed         : Boolean;
 888       External_Name_Exp_Casing   : External_Casing_Type;
 889       External_Name_Imp_Casing   : External_Casing_Type;
 890       Polling_Required           : Boolean;
 891       Use_VADS_Size              : Boolean;
 892    end record;
 893
 894 end Opt;