File : opt.ads


   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                  O P T                                   --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2016, 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.                                     --
  17 --                                                                          --
  18 --                                                                          --
  19 --                                                                          --
  20 --                                                                          --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31 
  32 --  This package contains global flags set by the initialization routine from
  33 --  the command line and referenced throughout the compiler, the binder, or
  34 --  other GNAT tools. The comments indicate which options are used by which
  35 --  programs (GNAT, GNATBIND, GNATLINK, GNATMAKE, etc).
  36 
  37 --  Some flags are labelled "PROJECT MANAGER". These are used by tools that
  38 --  use the Project Manager. These tools include gnatmake, gnatname, the gnat
  39 --  driver, gnatclean, gprbuild and gprclean.
  40 
  41 with Hostparm; use Hostparm;
  42 with Types;    use Types;
  43 
  44 pragma Warnings (Off);
  45 --  This package is used also by gnatcoll
  46 with System.Strings; use System.Strings;
  47 with System.WCh_Con; use System.WCh_Con;
  48 pragma Warnings (On);
  49 
  50 package Opt is
  51 
  52    ----------------------
  53    -- Checksum Control --
  54    ----------------------
  55 
  56    --  Checksums are computed for sources to check for sources being the same
  57    --  from a compilation point of view (e.g. spelling of identifiers and
  58    --  white space layout do not count in this computation).
  59 
  60    --  The way the checksum is computed has evolved across the various versions
  61    --  of GNAT. When gprbuild is called with -m, the checksums must be computed
  62    --  the same way in gprbuild as it was in the GNAT version of the compiler.
  63    --  The different ways are
  64 
  65    --    Version 6.4 and later:
  66 
  67    --      The Accumulate_Token_Checksum procedure is called after each numeric
  68    --      literal and each identifier/keyword. For keywords, Tok_Identifier is
  69    --      used in the call to Accumulate_Token_Checksum.
  70 
  71    --    Versions 5.04 to 6.3:
  72 
  73    --      For keywords, the token value were used in the call to procedure
  74    --      Accumulate_Token_Checksum. Type Token_Type did not include Tok_Some.
  75 
  76    --    Versions 5.03:
  77 
  78    --      For keywords, the token value were used in the call to
  79    --      Accumulate_Token_Checksum. Type Token_Type did not include
  80    --      Tok_Interface, Tok_Overriding, Tok_Synchronized and Tok_Some.
  81 
  82    --    Versions 5.02 and before:
  83 
  84    --      No calls to procedure Accumulate_Token_Checksum (the checksum
  85    --      mechanism was introduced in version 5.03).
  86 
  87    --  To signal to the scanner whether Accumulate_Token_Checksum needs to be
  88    --  called and what versions to call, the following Boolean flags are used:
  89 
  90    Checksum_Accumulate_Token_Checksum : Boolean := True;
  91    --  GPRBUILD
  92    --  Set to False by gprbuild when the version of GNAT is 5.02 or before. If
  93    --  this switch is False, then we do not call Accumulate_Token_Checksum, so
  94    --  the setting of the following two flags is irrelevant.
  95 
  96    Checksum_GNAT_6_3 : Boolean := False;
  97    --  GPRBUILD
  98    --  Set to True by gprbuild when the version of GNAT is 6.3 or before.
  99 
 100    Checksum_GNAT_5_03 : Boolean := False;
 101    --  GPRBUILD
 102    --  Set to True by gprbuild when the version of GNAT is 5.03 or before.
 103 
 104    ----------------------------------------------
 105    -- Settings of Modes for Current Processing --
 106    ----------------------------------------------
 107 
 108    --  The following mode values represent the current state of processing.
 109    --  The values set here are the default values. Unless otherwise noted,
 110    --  the value may be reset in Switch-? with an appropriate switch. In
 111    --  some cases, the values can also be modified by pragmas, and in the
 112    --  case of some binder variables, Gnatbind.Scan_Bind_Arg may modify
 113    --  the default values.
 114 
 115    Latest_Ada_Only : Boolean := False;
 116    --  If True, the only value valid for Ada_Version is Ada_Version_Type'Last,
 117    --  trying to specify other values will be ignored (in case of pragma
 118    --  Ada_xxx) or generate an error (in case of -gnat83/95/xx switches).
 119 
 120    type Ada_Version_Type is (Ada_83, Ada_95, Ada_2005, Ada_2012);
 121    pragma Ordered (Ada_Version_Type);
 122    --  Versions of Ada for Ada_Version below. Note that these are ordered,
 123    --  so that tests like Ada_Version >= Ada_95 are legitimate and useful.
 124    --  Think twice before using "="; Ada_Version >= Ada_2012 is more likely
 125    --  what you want, because it will apply to future versions of the language.
 126 
 127    Ada_Version_Default : constant Ada_Version_Type := Ada_2012;
 128    pragma Warnings (Off, Ada_Version_Default);
 129    --  GNAT
 130    --  Default Ada version if no switch given. The Warnings off is to kill
 131    --  constant condition warnings.
 132 
 133    Ada_Version : Ada_Version_Type := Ada_Version_Default;
 134    --  GNAT
 135    --  Current Ada version for compiler, as set by configuration pragmas,
 136    --  compiler switches, or implicitly (to Ada_Version_Runtime) when a
 137    --  predefined or internal file is compiled.
 138 
 139    Ada_Version_Pragma : Node_Id := Empty;
 140    --  Reflects the Ada_xxx pragma that resulted in setting Ada_Version. Used
 141    --  to specialize error messages complaining about the Ada version in use.
 142 
 143    Ada_Version_Explicit : Ada_Version_Type := Ada_Version_Default;
 144    --  GNAT
 145    --  Like Ada_Version, but does not get set implicitly for predefined or
 146    --  internal units, so it reflects the Ada version explicitly set using
 147    --  configuration pragmas or compiler switches (or if neither appears, it
 148    --  remains set to Ada_Version_Default). This is used in the rare cases
 149    --  (notably pragma Obsolescent) where we want the explicit version set.
 150 
 151    Ada_Version_Runtime : Ada_Version_Type := Ada_2012;
 152    --  GNAT
 153    --  Ada version used to compile the runtime. Used to set Ada_Version (but
 154    --  not Ada_Version_Explicit) when compiling predefined or internal units.
 155 
 156    Ada_Final_Suffix : constant String := "final";
 157    Ada_Final_Name   : String_Ptr := new String'("ada" & Ada_Final_Suffix);
 158    --  GNATBIND
 159    --  The name of the procedure that performs the finalization at the end of
 160    --  execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.
 161 
 162    Ada_Init_Suffix : constant String := "init";
 163    Ada_Init_Name   : String_Ptr := new String'("ada" & Ada_Init_Suffix);
 164    --  GNATBIND
 165    --  The name of the procedure that performs initialization at the start
 166    --  of execution. This variable may be modified by Gnatbind.Scan_Bind_Arg.
 167 
 168    Ada_Main_Name_Suffix : constant String := "main";
 169    --  GNATBIND
 170    --  The suffix for Ada_Main_Name. Defined as a constant here so that it
 171    --  can be referenced in a uniform manner to create either the default
 172    --  value of Ada_Main_Name (declared below), or the non-default name
 173    --  set by Gnatbind.Scan_Bind_Arg.
 174 
 175    Ada_Main_Name : String_Ptr := new String'("ada_" & Ada_Main_Name_Suffix);
 176    --  GNATBIND
 177    --  The name of the Ada package generated by the binder (when in Ada mode).
 178    --  This variable may be modified by Gnatbind.Scan_Bind_Arg.
 179 
 180    Address_Clause_Overlay_Warnings : Boolean := True;
 181    --  GNAT
 182    --  Set False to disable address clause warnings. Modified by use of
 183    --  -gnatwo/O.
 184 
 185    Address_Is_Private : Boolean := False;
 186    --  GNAT, GNATBIND
 187    --  Set True if package System has the line "type Address is private;"
 188 
 189    All_Errors_Mode : Boolean := False;
 190    --  GNAT
 191    --  Flag set to force display of multiple errors on a single line and
 192    --  also repeated error messages for references to undefined identifiers
 193    --  and certain other repeated error messages. Set by use of -gnatf.
 194 
 195    Allow_Integer_Address : Boolean := False;
 196    --  GNAT
 197    --  Allow use of integer expression in a context requiring System.Address.
 198    --  Set by the use of configuration pragma Allow_Integer_Address Also set
 199    --  in relaxed semantics mode for use by CodePeer or when -gnatd.M is used.
 200 
 201    All_Sources : Boolean := False;
 202    --  GNATBIND
 203    --  Set to True to require all source files to be present. This flag is
 204    --  directly modified by gnatmake to affect the shared binder routines.
 205 
 206    Alternate_Main_Name : String_Ptr := null;
 207    --  GNATBIND
 208    --  Set to non-null when Bind_Alternate_Main_Name is True. This value
 209    --  is modified as needed by Gnatbind.Scan_Bind_Arg.
 210 
 211    ASIS_GNSA_Mode : Boolean := False;
 212    --  GNAT
 213    --  Enable GNSA back-end processing assuming ASIS_Mode is already set to
 214    --  True. ASIS_GNSA mode suppresses the call to gigi.
 215 
 216    ASIS_Mode : Boolean := False;
 217    --  GNAT
 218    --  Enable semantic checks and tree transformations that are important
 219    --  for ASIS but that are usually skipped if Operating_Mode is set to
 220    --  Check_Semantics. This flag does not have the corresponding option to set
 221    --  it ON. It is set ON when Tree_Output is set ON, it can also be set ON
 222    --  from the code of GNSA-based tool (a client may need to set ON the
 223    --  Back_Annotate_Rep_Info flag in this case. At the moment this does not
 224    --  make very much sense, because GNSA cannot do back annotation).
 225 
 226    Assertions_Enabled : Boolean := False;
 227    --  GNAT
 228    --  Indicates default policy (True = Check, False = Ignore) to be applied
 229    --  to all assertion aspects and pragmas, and to pragma Debug, if there is
 230    --  no overriding Assertion_Policy, Check_Policy, or Debug_Policy pragma.
 231    --  Set True by use of -gnata.
 232 
 233    Assume_No_Invalid_Values : Boolean := False;
 234    --  GNAT Normally, in accordance with (RM 13.9.1 (9-11)) the front end
 235    --  assumes that values could have invalid representations, unless it can
 236    --  clearly prove that the values are valid. If this switch is set (by
 237    --  pragma Assume_No_Invalid_Values (On)), then the compiler assumes values
 238    --  are valid and in range of their representations. This feature is now
 239    --  fully enabled in the compiler.
 240 
 241    Back_Annotate_Rep_Info : Boolean := False;
 242    --  GNAT
 243    --  If set True, enables back annotation of representation information
 244    --  by gigi, even in -gnatc mode. This is set True by the use of -gnatR
 245    --  (list representation information) or -gnatt (generate tree). It is
 246    --  also set true if certain Unchecked_Conversion instantiations require
 247    --  checking based on annotated values.
 248 
 249    Back_End_Handles_Limited_Types : Boolean;
 250    --  This flag is set true if the back end can properly handle limited or
 251    --  other by reference types, and avoid copies. If this flag is False, then
 252    --  the front end does special expansion for if/case expressions to make
 253    --  sure that no copy occurs. If the flag is True, then the expansion for
 254    --  if and case expressions relies on the back end properly handling things.
 255    --  Currently the default is False for all cases (set in gnat1drv). The
 256    --  default can be modified using -gnatd.L (sets the flag True). This is
 257    --  used to test the possibility of having the backend handle this.
 258 
 259    Back_End_Inlining : Boolean := False;
 260    --  GNAT
 261    --  Set True to activate inlining by back-end expansion. This is the normal
 262    --  default mode for gcc targets, so it is True on such targets unless the
 263    --  switches -gnatN or -gnatd.z are used. See circuitry in gnat1drv for the
 264    --  exact conditions for setting this switch.
 265 
 266    Bind_Alternate_Main_Name : Boolean := False;
 267    --  GNATBIND
 268    --  True if main should be called Alternate_Main_Name.all.
 269    --  This variable may be set to True by Gnatbind.Scan_Bind_Arg.
 270 
 271    Bind_Main_Program : Boolean := True;
 272    --  GNATBIND
 273    --  Set to False if not binding main Ada program
 274 
 275    Bind_For_Library : Boolean := False;
 276    --  GNATBIND
 277    --  Set to True if the binder needs to generate a file designed for building
 278    --  a library. May be set to True by Gnatbind.Scan_Bind_Arg.
 279 
 280    Bind_Only : Boolean := False;
 281    --  GNATMAKE, GPRBUILD
 282    --  Set to True to skip compile and link steps
 283    --  (except when Compile_Only and/or Link_Only are True).
 284 
 285    Blank_Deleted_Lines : Boolean := False;
 286    --  GNAT, GNATPREP
 287    --  Output empty lines for each line of preprocessed input that is deleted
 288    --  in the output, including preprocessor lines starting with a '#'.
 289 
 290    Brief_Output : Boolean := False;
 291    --  GNAT, GNATBIND
 292    --  Force brief error messages to standard error, even if verbose mode is
 293    --  set (so that main error messages go to standard output).
 294 
 295    Build_Bind_And_Link_Full_Project : Boolean := False;
 296    --  GNATMAKE
 297    --  Set to True to build, bind and link all the sources of a project file
 298    --  (switch -B)
 299 
 300    Check_Aliasing_Of_Parameters : Boolean := False;
 301    --  GNAT
 302    --  Set to True to detect whether subprogram parameters and function results
 303    --  alias the same object(s).
 304 
 305    Check_Float_Overflow : Boolean := False;
 306    --  GNAT
 307    --  Set to True to check that operations on predefined unconstrained float
 308    --  types (e.g. Float, Long_Float) do not overflow and generate infinities
 309    --  or invalid values. Set by the Check_Float_Overflow pragma, or by use
 310    --  of the -gnateF switch.
 311 
 312    Check_Object_Consistency : Boolean := False;
 313    --  GNATBIND, GNATMAKE
 314    --  Set to True to check whether every object file is consistent with its
 315    --  corresponding ada library information (ALI) file. An object file is
 316    --  inconsistent with the corresponding ALI file if the object file does
 317    --  not exist or if it has an older time stamp than the ALI file. Default
 318    --  above is for GNATBIND. GNATMAKE overrides this default to True (see
 319    --  Make.Initialize) since we normally do need to check source consistencies
 320    --  in gnatmake.
 321 
 322    Check_Only : Boolean := False;
 323    --  GNATBIND
 324    --  Set to True to do checks only, no output of binder file
 325 
 326    Check_Policy_List : Node_Id := Empty;
 327    --  GNAT
 328    --  This points to the list of N_Pragma nodes for Check_Policy pragmas
 329    --  that are linked through the Next_Pragma fields, with the list being
 330    --  terminated by Empty. The order is most recently processed first. Note
 331    --  that Push_Scope and Pop_Scope in Sem_Ch8 save and restore the value
 332    --  of this variable, implementing the required scope control for pragmas
 333    --  appearing in a declarative part.
 334 
 335    Check_Readonly_Files : Boolean := False;
 336    --  GNATMAKE
 337    --  Set to True to check readonly files during the make process
 338 
 339    Check_Source_Files : Boolean := True;
 340    --  GNATBIND, GNATMAKE
 341    --  Set to True to enable consistency checking for any source files that
 342    --  are present (i.e. date must match the date in the library info file).
 343    --  Set to False for object file consistency check only. This flag is
 344    --  directly modified by gnatmake, to affect the shared binder routines.
 345 
 346    Check_Switches : Boolean := False;
 347    --  GNATMAKE, GPBUILD
 348    --  Set to True to check compiler options during the make process
 349 
 350    Check_Unreferenced : Boolean := False;
 351    --  GNAT
 352    --  Set to True to enable checking for unreferenced entities other
 353    --  than formal parameters (for which see Check_Unreferenced_Formals)
 354    --  Modified by use of -gnatwu/U.
 355 
 356    Check_Unreferenced_Formals : Boolean := False;
 357    --  GNAT
 358    --  Set to True to check for unreferenced formals. This is turned on by
 359    --  -gnatwa/wf/wu and turned off by -gnatwA/wF/wU.
 360 
 361    Check_Validity_Of_Parameters : Boolean := False;
 362    --  GNAT
 363    --  Set to True to check for proper scalar initialization of subprogram
 364    --  parameters on both entry and exit. Turned on by??? turned off by???
 365 
 366    Check_Withs : Boolean := False;
 367    --  GNAT
 368    --  Set to True to enable checking for unused withs, and also the case
 369    --  of withing a package and using none of the entities in the package.
 370    --  Modified by use of -gnatwu/U.
 371 
 372    CodePeer_Mode : Boolean := False;
 373    --  GNAT, GNATBIND, GPRBUILD
 374    --  Enable full CodePeer mode (SCIL generation, disable switches that
 375    --  interact badly with it, etc...). This is turned on by -gnatC.
 376 
 377    Commands_To_Stdout : Boolean := False;
 378    --  GNATMAKE
 379    --  True if echoed commands to be written to stdout instead of stderr
 380 
 381    Comment_Deleted_Lines : Boolean := False;
 382    --  GNATPREP
 383    --  True if source lines removed by the preprocessor should be commented
 384    --  in the output file.
 385 
 386    Compilation_Time : String (1 .. 19);
 387    --  GNAT
 388    --  Compilation date and time in form YYYY-MM-DD HH:MM:SS
 389 
 390    Compile_Only : Boolean := False;
 391    --  GNATMAKE, GNATCLEAN, GPBUILD, GPRCLEAN
 392    --  GNATMAKE, GPRBUILD:
 393    --    set True to skip bind and link steps (except when Bind_Only is True)
 394    --  GNATCLEAN, GPRCLEAN:
 395    --    set True to delete only the files produced by the compiler but not the
 396    --    library files or the executable files.
 397 
 398    Compiler_Unit : Boolean := False;
 399    --  GNAT1
 400    --  Set True by an occurrence of pragma Compiler_Unit_Warning (or of the
 401    --  obsolete pragma Compiler_Unit) in the main unit. Once set True, stays
 402    --  True, since any units that are with'ed directly or indirectly by
 403    --  a Compiler_Unit_Warning main unit are subject to the same restrictions.
 404    --  Such units really should have their own pragmas, but we do not bother to
 405    --  check for that, so this transitivity provides extra checking.
 406 
 407    Config_File : Boolean := True;
 408    --  GNAT
 409    --  Set to False to inhibit reading and processing of gnat.adc file
 410 
 411    Config_File_Names : String_List_Access := null;
 412    --  GNAT
 413    --  Names of configuration pragmas files (given by switches -gnatec)
 414 
 415    Configurable_Run_Time_Mode : Boolean := False;
 416    --  GNAT, GNATBIND
 417    --  Set True if the compiler is operating in configurable run-time mode.
 418    --  This happens if the flag Targparm.Configurable_Run_TimeMode_On_Target
 419    --  is set True, or if pragma No_Run_Time is used. See the spec of Rtsfind
 420    --  for details on the handling of the latter pragma.
 421 
 422    Constant_Condition_Warnings : Boolean := False;
 423    --  GNAT
 424    --  Set to True to activate warnings on constant conditions. Modified by
 425    --  use of -gnatwc/C.
 426 
 427    Create_Mapping_File : Boolean := False;
 428    --  GNATMAKE
 429    --  Set to True (-C switch) to indicate that the compiler will be invoked
 430    --  with a mapping file (-gnatem compiler switch).
 431 
 432    subtype Debug_Level_Value is Nat range 0 .. 3;
 433    Debugger_Level : Debug_Level_Value := 0;
 434    --  GNAT, GNATBIND
 435    --  The value given to the -g parameter. The default value for -g with
 436    --  no value is 2. If no -g is specified, defaults to 0.
 437    --  Note that the generated code should never depend on this variable,
 438    --  since we want debug info to be nonintrusive on the generate code.
 439 
 440    Default_Exit_Status : Int := 0;
 441    --  GNATBIND
 442    --  Set the default exit status value. Set by the -Xnnn switch for the
 443    --  binder.
 444 
 445    Debug_Generated_Code : Boolean := False;
 446    --  GNAT
 447    --  Set True (-gnatD switch) to debug generated expanded code instead
 448    --  of the original source code. Causes debugging information to be
 449    --  written with respect to the generated code file that is written.
 450 
 451    Default_Pool : Node_Id := Empty;
 452    --  GNAT
 453    --  Used to record the storage pool name (or null literal) that is the
 454    --  argument of an applicable pragma Default_Storage_Pool.
 455    --    Empty:       No pragma Default_Storage_Pool applies.
 456    --    N_Null node: "pragma Default_Storage_Pool (null);" applies.
 457    --    otherwise:   "pragma Default_Storage_Pool (X);" applies, and
 458    --                 this points to the name X.
 459    --  Push_Scope and Pop_Scope in Sem_Ch8 save and restore this value.
 460    Default_Stack_Size : Int := -1;
 461    --  GNATBIND
 462    --  Set to default primary stack size in units of bytes. Set by
 463    --  the -dnnn switch for the binder. A value of -1 indicates that no
 464    --  default was set by the binder.
 465 
 466    Default_Sec_Stack_Size : Int := -1;
 467    --  GNATBIND
 468    --  Set to default secondary stack size in units of bytes. Set by
 469    --  the -Dnnn switch for the binder. A value of -1 indicates that no
 470    --  default was set by the binder, and that the default should be the
 471    --  initial value of System.Secondary_Stack.Default_Secondary_Stack_Size.
 472 
 473    Default_SSO : Character := ' ';
 474    --  GNAT
 475    --  Set if a pragma Default_Scalar_Storage_Order has been given. The value
 476    --  of ' ' indicates that no default has been set, otherwise the value is
 477    --  either 'H' for High_Order_First or 'L' for Lower_Order_First.
 478 
 479    Detect_Blocking : Boolean := False;
 480    --  GNAT
 481    --  Set True to force the run time to raise Program_Error if calls to
 482    --  potentially blocking operations are detected from protected actions.
 483 
 484    Directories_Must_Exist_In_Projects : Boolean := True;
 485    --  PROJECT MANAGER
 486    --  Set to False with switch -f of gnatclean and gprclean
 487 
 488    Display_Compilation_Progress : Boolean := False;
 489    --  GNATMAKE, GPRBUILD
 490    --  Set True (-d switch) to display information on progress while compiling
 491    --  files. Internal flag to be used in conjunction with an IDE (e.g GPS).
 492 
 493    type Distribution_Stub_Mode_Type is
 494    --  GNAT
 495      (No_Stubs,
 496       --  Normal mode, no generation/compilation of distribution stubs
 497 
 498       Generate_Receiver_Stub_Body,
 499       --  The unit being compiled is the RCI body, and the compiler will
 500       --  generate the body for the receiver stubs and compile it.
 501 
 502       Generate_Caller_Stub_Body);
 503       --  The unit being compiled is the RCI spec, and the compiler will
 504       --  generate the body for the caller stubs and compile it.
 505 
 506    Distribution_Stub_Mode : Distribution_Stub_Mode_Type := No_Stubs;
 507    --  GNAT
 508    --  This enumeration variable indicates the five states of distribution
 509    --  annex stub generation/compilation.
 510 
 511    Do_Not_Execute : Boolean := False;
 512    --  GNATMAKE
 513    --  Set to True if no actual compilations should be undertaken
 514 
 515    Dump_Source_Text : Boolean := False;
 516    --  GNAT
 517    --  Set to True (by -gnatL) to dump source text intermingled with generated
 518    --  code. Effective only if either of Debug/Print_Generated_Code is true.
 519 
 520    Dynamic_Elaboration_Checks : Boolean := False;
 521    --  GNAT
 522    --  Set True for dynamic elaboration checking mode, as set by the -gnatE
 523    --  switch or by the use of pragma Elaboration_Checks (Dynamic).
 524 
 525    Dynamic_Stack_Measurement : Boolean := False;
 526    --  GNATBIND
 527    --  Set True to enable dynamic stack measurement (-u flag for gnatbind)
 528 
 529    Dynamic_Stack_Measurement_Array_Size : Nat := 100;
 530    --  GNATBIND
 531    --  Number of measurements we want to store during dynamic stack analysis.
 532    --  When the buffer is full, non-storable results will be output on the fly.
 533    --  The value is relevant only if Dynamic_Stack_Measurement is set. Set
 534    --  by processing of -u flag for gnatbind.
 535 
 536    Elab_Dependency_Output : Boolean := False;
 537    --  GNATBIND
 538    --  Set to True to output complete list of elaboration constraints
 539 
 540    Elab_Order_Output : Boolean := False;
 541    --  GNATBIND
 542    --  Set to True to output chosen elaboration order
 543 
 544    Elab_Info_Messages : Boolean := False;
 545    --  GNAT
 546    --  Set to True to output info messages for static elabmodel (-gnatel)
 547 
 548    Elab_Warnings : Boolean := False;
 549    --  GNAT
 550    --  Set to True to generate elaboration warnings (-gnatwl)
 551 
 552    Error_Msg_Line_Length : Nat := 0;
 553    --  GNAT
 554    --  Records the error message line length limit. If this is set to zero,
 555    --  then we get the old style behavior, in which each call to the error
 556    --  message routines generates one line of output as a separate message.
 557    --  If it is set to a non-zero value, then continuation lines are folded
 558    --  to make a single long message, and then this message is split up into
 559    --  multiple lines not exceeding the specified length. Set by -gnatj=nn.
 560 
 561    Error_To_Warning : Boolean := False;
 562    --  GNAT
 563    --  If True, then certain error messages (e.g. parameter overlap messages
 564    --  for procedure calls in Ada 2012 mode) are treated as warnings instead
 565    --  of errors. Set by debug flag -gnatd.E. A search for Error_To_Warning
 566    --  will identify affected messages.
 567 
 568    Exception_Handler_Encountered : Boolean := False;
 569    --  GNAT
 570    --  This flag is set true if the parser encounters an exception handler.
 571    --  It is used to set Warn_On_Exception_Propagation True if the restriction
 572    --  No_Exception_Propagation is set.
 573 
 574    Exception_Extra_Info : Boolean := False;
 575    --  GNAT
 576    --  True when switch -gnateE is used. When True, generate extra information
 577    --  associated with exception messages (in particular range and index
 578    --  checks).
 579 
 580    Exception_Locations_Suppressed : Boolean := False;
 581    --  GNAT
 582    --  Set to True if a Suppress_Exception_Locations configuration pragma is
 583    --  currently active.
 584 
 585    type Exception_Mechanism_Type is
 586    --  Determines the kind of mechanism used to handle exceptions
 587    --
 588      (Front_End_SJLJ,
 589       --  Exceptions use setjmp/longjmp generated explicitly by the front end
 590       --  (this includes gigi or other equivalent parts of the code generator).
 591       --  AT END handlers are converted into exception handlers by the front
 592       --  end in this mode.
 593 
 594       Back_End_ZCX,
 595       --  Exceptions are handled by the back end. The front end simply
 596       --  generates the handlers as they appear in the source, and AT END
 597       --  handlers are left untouched (they are not converted into exception
 598       --  handlers when operating in this mode). Propagation is performed
 599       --  using a frame unwinding scheme and requires no particular setup code
 600       --  at handler sites on regular execution paths.
 601 
 602       Back_End_SJLJ);
 603       --  Similar to Back_End_ZCX with respect to the front-end processing
 604       --  of regular and AT-END handlers. A setjmp/longjmp scheme is used to
 605       --  propagate and setup handler contexts on regular execution paths.
 606 
 607    pragma Convention (C, Exception_Mechanism_Type);
 608 
 609    Exception_Mechanism : Exception_Mechanism_Type := Front_End_SJLJ;
 610    --  GNAT
 611    --  Set to the appropriate value depending on the flags in system.ads
 612    --  (Frontend_Exceptions + ZCX_By_Default). The C convention is there to
 613    --  allow access by gigi.
 614 
 615    function Back_End_Exceptions return Boolean;
 616    function Front_End_Exceptions return Boolean;
 617    function ZCX_Exceptions return Boolean;
 618    function SJLJ_Exceptions return Boolean;
 619    --  GNAT
 620    --  Various properties of the active Exception_Mechanism
 621 
 622    Exception_Tracebacks : Boolean := False;
 623    --  GNATBIND
 624    --  Set to True to store tracebacks in exception occurrences (-Ea or -E)
 625 
 626    Exception_Tracebacks_Symbolic : Boolean := False;
 627    --  GNATBIND
 628    --  Set to True to store tracebacks in exception occurrences and enable
 629    --  symbolic tracebacks (-Es).
 630 
 631    Extensions_Allowed : Boolean := False;
 632    --  GNAT
 633    --  Set to True by switch -gnatX if GNAT specific language extensions
 634    --  are allowed. Currently there are no such defined extensions.
 635 
 636    type External_Casing_Type is (
 637      As_Is,       -- External names cased as they appear in the Ada source
 638      Uppercase,   -- External names forced to all uppercase letters
 639      Lowercase);  -- External names forced to all lowercase letters
 640 
 641    External_Name_Imp_Casing : External_Casing_Type := Lowercase;
 642    --  GNAT
 643    --  The setting of this flag determines the casing of external names
 644    --  when the name is implicitly derived from an entity name (i.e. either
 645    --  no explicit External_Name or Link_Name argument is used, or, in the
 646    --  case of extended DEC pragmas, the external name is given using an
 647    --  identifier. The As_Is setting is not permitted here (since this would
 648    --  create Ada source programs that were case sensitive).
 649 
 650    External_Name_Exp_Casing : External_Casing_Type := As_Is;
 651    --  GNAT
 652    --  The setting of this flag determines the casing of an external name
 653    --  specified explicitly with a string literal. As_Is means the string
 654    --  literal is used as given with no modification to the casing. If
 655    --  Lowercase or Uppercase is set, then the string is forced to all
 656    --  lowercase or all uppercase letters as appropriate. Note that this
 657    --  setting has no effect if the external name is given using an identifier
 658    --  in the case of extended DEC import/export pragmas (in this case the
 659    --  casing is controlled by External_Name_Imp_Casing), and also has no
 660    --  effect if an explicit Link_Name is supplied (a link name is always
 661    --  used exactly as given).
 662 
 663    External_Unit_Compilation_Allowed : Boolean := False;
 664    --  GNATMAKE
 665    --  When True (set by gnatmake switch -x), allow compilation of sources
 666    --  that are not part of any project file.
 667 
 668    Fast_Math : Boolean := False;
 669    --  GNAT
 670    --  Indicates the current setting of Fast_Math mode, as set by the use
 671    --  of a Fast_Math pragma (set True by Fast_Math (On)).
 672 
 673    Force_ALI_Tree_File : Boolean := False;
 674    --  GNAT
 675    --  Force generation of ALI file even if errors are encountered. Also forces
 676    --  generation of tree file if -gnatt is also set. Set on by use of -gnatQ.
 677 
 678    Disable_ALI_File : Boolean := False;
 679    --  GNAT
 680    --  Disable generation of ALI file
 681 
 682    Follow_Links_For_Files : Boolean := False;
 683    --  PROJECT MANAGER
 684    --  Set to True (-eL) to process the project files in trusted mode. If
 685    --  Follow_Links is False, it is assumed that the project doesn't contain
 686    --  any file duplicated through symbolic links (although the latter are
 687    --  still valid if they point to a file which is outside of the project),
 688    --  and that no directory has a name which is a valid source name.
 689 
 690    Follow_Links_For_Dirs : Boolean := False;
 691    --  PROJECT MANAGER
 692    --  Set to True if directories can be links in this project, and therefore
 693    --  additional system calls must be performed to ensure that we always see
 694    --  the same full name for each directory.
 695 
 696    Force_Checking_Of_Elaboration_Flags : Boolean := False;
 697    --  GNATBIND
 698    --  True if binding with forced checking of the elaboration flags
 699    --  (-F switch set).
 700 
 701    Force_Compilations : Boolean := False;
 702    --  GNATMAKE, GPRBUILD
 703    --  Set to force recompilations even when the objects are up-to-date.
 704 
 705    Front_End_Inlining : Boolean := False;
 706    --  GNAT
 707    --  Set True to activate inlining by front-end expansion (even on GCC
 708    --  targets, where inlining is normally handled by the back end). Set by
 709    --  the flag -gnatN (which is now considered obsolescent, since the GCC
 710    --  back end can do a better job of inlining than the front end these days.
 711 
 712    Full_Path_Name_For_Brief_Errors : Boolean := False;
 713    --  PROJECT MANAGER
 714    --  When True, in Brief_Output mode, each error message line will start with
 715    --  the full path name of the source. When False, only the file name without
 716    --  directory information is used.
 717 
 718    Full_List : Boolean := False;
 719    --  GNAT
 720    --  Set True to generate full source listing with embedded errors
 721 
 722    Full_List_File_Name : String_Ptr := null;
 723    --  GNAT
 724    --  Set to file name to generate full source listing to named file (or if
 725    --  the name is of the form .xxx, then to name.xxx where name is the source
 726    --  file name with extension stripped.
 727 
 728    Generate_C_Code : Boolean := False;
 729    --  GNAT
 730    --  If True, the Cprint circuitry to generate C code output is activated.
 731    --  Set True by use of -gnateg or -gnatd.V.
 732 
 733    Generate_CodePeer_Messages : Boolean := False;
 734    --  GNAT
 735    --  Generate CodePeer messages. Ignored if CodePeer_Mode is false. This is
 736    --  turned on by -gnateC.
 737 
 738    Generate_Processed_File : Boolean := False;
 739    --  GNAT
 740    --  True when switch -gnateG is used. When True, create in a file
 741    --  <source>.prep, if the source is preprocessed.
 742 
 743    Generate_SCIL : Boolean := False;
 744    --  GNAT
 745    --  Set True to activate SCIL code generation.
 746 
 747    Generate_SCO : Boolean := False;
 748    --  GNAT
 749    --  True when switch -fdump-scos (or -gnateS) is used. When True, Source
 750    --  Coverage Obligation (SCO) information is generated and output in the ALI
 751    --  file. See unit Par_SCO for full details.
 752 
 753    Generate_SCO_Instance_Table : Boolean := False;
 754    --  GNAT
 755    --  True when switch -fdump-scos is used. When True, a table of instances is
 756    --  included in SCOs.
 757 
 758    Generating_Code : Boolean := False;
 759    --  GNAT
 760    --  True if the frontend finished its work and has called the backend to
 761    --  process the tree and generate the object file.
 762 
 763    type Ghost_Mode_Type is (None, Check, Ignore);
 764    --  Possible legal modes that can be set by aspect/pragma Ghost as well as
 765    --  value None, which indicates that no such aspect/pragma applies.
 766 
 767    Ghost_Mode : Ghost_Mode_Type := None;
 768    --  GNAT
 769    --  Current Ghost mode setting
 770 
 771    Global_Discard_Names : Boolean := False;
 772    --  GNAT, GNATBIND
 773    --  True if a pragma Discard_Names appeared as a configuration pragma for
 774    --  the current compilation unit.
 775 
 776    GNAT_Encodings : Int;
 777    pragma Import (C, GNAT_Encodings, "gnat_encodings");
 778    --  Constant controlling the balance between GNAT encodings and standard
 779    --  DWARF to emit in the debug information. It accepts the following values.
 780 
 781    DWARF_GNAT_Encodings_All     : constant Int := 0;
 782    DWARF_GNAT_Encodings_GDB     : constant Int := 1;
 783    DWARF_GNAT_Encodings_Minimal : constant Int := 2;
 784 
 785    Identifier_Character_Set : Character;
 786    --  GNAT
 787    --  This variable indicates the character set to be used for identifiers.
 788    --  The possible settings are:
 789    --    '1'  Latin-1 (ISO-8859-1)
 790    --    '2'  Latin-2 (ISO-8859-2)
 791    --    '3'  Latin-3 (ISO-8859-3)
 792    --    '4'  Latin-4 (ISO-8859-4)
 793    --    '5'  Latin-Cyrillic (ISO-8859-5)
 794    --    '9'  Latin-9 (ISO-8859-15)
 795    --    'p'  PC (US, IBM page 437)
 796    --    '8'  PC (European, IBM page 850)
 797    --    'f'  Full upper set (all distinct)
 798    --    'n'  No upper characters (Ada 83 rules)
 799    --    'w'  Latin-1 plus wide characters allowed in identifiers
 800    --
 801    --  The setting affects the set of letters allowed in identifiers and the
 802    --  upper/lower case equivalences. It does not affect the interpretation of
 803    --  character and string literals, which are always stored using the actual
 804    --  coding in the source program. This variable is initialized to the
 805    --  default value appropriate to the system (in Osint.Initialize), and then
 806    --  reset if a command line switch is used to change the setting.
 807 
 808    Ignore_Pragma_SPARK_Mode : Boolean := False;
 809    --  GNAT
 810    --  Set True to ignore the semantics and effects of pragma SPARK_Mode when
 811    --  the pragma appears inside an instance whose enclosing context is subject
 812    --  to SPARK_Mode "off".
 813 
 814    Ignore_Rep_Clauses : Boolean := False;
 815    --  GNAT
 816    --  Set True to ignore all representation clauses. Useful when compiling
 817    --  code from foreign compilers for checking or ASIS purposes. Can be
 818    --  set True by use of -gnatI.
 819 
 820    Ignore_Style_Checks_Pragmas : Boolean := False;
 821    --  GNAT
 822    --  Set True to ignore all Style_Checks pragmas. Can be set True by use
 823    --  of -gnateY.
 824 
 825    Ignore_Unrecognized_VWY_Switches : Boolean := False;
 826    --  GNAT
 827    --  Set True to ignore unrecognized y, V, w switches. Can be set True
 828    --  by use of -gnateu, causing subsequent unrecognized switches to result
 829    --  in a warning rather than an error.
 830 
 831    Implementation_Unit_Warnings : Boolean := True;
 832    --  GNAT
 833    --  Set True to active warnings for use of implementation internal units.
 834    --  Modified by use of -gnatwi/-gnatwI.
 835 
 836    Implicit_Packing : Boolean := False;
 837    --  GNAT
 838    --  If set True, then a Size attribute clause on an array is allowed to
 839    --  cause implicit packing instead of generating an error message. Set by
 840    --  use of pragma Implicit_Packing.
 841 
 842    Ineffective_Inline_Warnings : Boolean := False;
 843    --  GNAT
 844    --  Set True to activate warnings if front-end inlining (-gnatN) is not able
 845    --  to actually inline a particular call (or all calls). Can be controlled
 846    --  by use of -gnatwp/-gnatwP. Also set True to activate warnings if
 847    --  frontend inlining is not able to inline a subprogram expected to
 848    --  be inlined in GNATprove mode.
 849 
 850    Init_Or_Norm_Scalars : Boolean := False;
 851    --  GNAT, GNATBIND
 852    --  Set True if a pragma Initialize_Scalars applies to the current unit.
 853    --  Also set True if a pragma Restriction (Normalize_Scalars) applies.
 854 
 855    Initialize_Scalars : Boolean := False;
 856    --  GNAT
 857    --  Set True if a pragma Initialize_Scalars applies to the current unit.
 858    --  Note that Init_Or_Norm_Scalars is also set to True if this is True.
 859 
 860    Initialize_Scalars_Mode1 : Character := 'I';
 861    Initialize_Scalars_Mode2 : Character := 'N';
 862    --  GNATBIND
 863    --  Set to two characters from -S switch (IN/LO/HI/EV/xx). The default
 864    --  is IN (invalid values), used if no -S switch is used.
 865 
 866    Inline_Active : Boolean := False;
 867    --  GNAT
 868    --  Set True to activate pragma Inline processing across modules. Default
 869    --  for now is not to inline across module boundaries.
 870 
 871    Inline_Level : Nat := 0;
 872    --  GNAT
 873    --  Set to indicate the inlining level: 0 means that an appropriate value is
 874    --  to be computed by the compiler based on the optimization level (-gnatn),
 875    --  1 is for moderate inlining across modules (-gnatn1) and 2 for full
 876    --  inlining across modules (-gnatn2).
 877 
 878    Interface_Library_Unit : Boolean := False;
 879    --  GNATBIND
 880    --  Set to True to indicate that at least one ALI file is an interface ALI:
 881    --  then elaboration flag checks are to be generated in the binder
 882    --  generated file.
 883 
 884    Invalid_Value_Used : Boolean := False;
 885    --  GNAT
 886    --  Set True if a valid Invalid_Value attribute is encountered
 887 
 888    Inline_Processing_Required : Boolean := False;
 889    --  GNAT
 890    --  Set True if inline processing is required. Inline processing is required
 891    --  if an active Inline pragma is processed. The flag is set for a pragma
 892    --  Inline or Inline_Always that is actually active.
 893 
 894    In_Place_Mode : Boolean := False;
 895    --  GNATMAKE
 896    --  Set True to store ALI and object files in place i.e. in the object
 897    --  directory if these files already exist or in the source directory
 898    --  if not.
 899 
 900    Keep_Going : Boolean := False;
 901    --  GNATMAKE, GPRBUILD
 902    --  When True signals to ignore compilation errors and keep processing
 903    --  sources until there is no more work.
 904 
 905    Keep_Temporary_Files : Boolean := False;
 906    --  GNATCMD, GNATMAKE, GPRBUILD
 907    --  When True the temporary files are not deleted. Set by switches -dn or
 908    --  --keep-temp-files.
 909 
 910    Leap_Seconds_Support : Boolean := False;
 911    --  GNATBIND
 912    --  Set to True to enable leap seconds support in Ada.Calendar and its
 913    --  children.
 914 
 915    Link_Only : Boolean := False;
 916    --  GNATMAKE, GPRBUILD
 917    --  Set to True to skip compile and bind steps (except when Bind_Only is
 918    --  set to True).
 919 
 920    List_Body_Required_Info : Boolean := False;
 921    --  GNATMAKE
 922    --  List info messages about why a package requires a body. Modified by use
 923    --  of -gnatw.y/.Y.
 924 
 925    List_Inherited_Aspects : Boolean := False;
 926    --  GNAT
 927    --  List inherited invariants, preconditions, and postconditions from
 928    --  Invariant'Class, Pre'Class, and Post'Class aspects. Also list inherited
 929    --  subtype predicates. Modified by use of -gnatw.l/.L.
 930 
 931    List_Restrictions : Boolean := False;
 932    --  GNATBIND
 933    --  Set to True to list restrictions pragmas that could apply to partition
 934 
 935    List_Units : Boolean := False;
 936    --  GNAT
 937    --  List units in the active library for a compilation (-gnatu switch)
 938 
 939    List_Closure : Boolean := False;
 940    --  GNATBIND
 941    --  List all sources in the closure of a main (-R or -Ra gnatbind switch)
 942 
 943    List_Closure_All : Boolean := False;
 944    --  GNATBIND
 945    --  List all sources in closure of main including run-time units (-Ra
 946    --  gnatbind switch).
 947 
 948    List_Dependencies : Boolean := False;
 949    --  GNATMAKE
 950    --  When True gnatmake verifies that the objects are up to date and outputs
 951    --  the list of object dependencies (-M switch). Output depends if -a switch
 952    --  is used or not. This list can be used directly in a Makefile.
 953 
 954    List_Representation_Info : Int range 0 .. 3 := 0;
 955    --  GNAT
 956    --  Set non-zero by -gnatR switch to list representation information.
 957    --  The settings are as follows:
 958    --
 959    --    0 = no listing of representation information (default as above)
 960    --    1 = list rep info for user defined record and array types
 961    --    2 = list rep info for all user defined types and objects
 962    --    3 = like 2, but variable fields are decoded symbolically
 963 
 964    List_Representation_Info_To_File : Boolean := False;
 965    --  GNAT
 966    --  Set true by -gnatRs switch. Causes information from -gnatR/1/2/3/m to be
 967    --  written to file.rep (where file is the name of the source file) instead
 968    --  of stdout. For example, if file x.adb is compiled using -gnatR2s then
 969    --  representation info is written to x.adb.ref.
 970 
 971    List_Representation_Info_Mechanisms : Boolean := False;
 972    --  GNAT
 973    --  Set true by -gnatRm switch. Causes information on mechanisms to be
 974    --  included in the representation output information.
 975 
 976    List_Preprocessing_Symbols : Boolean := False;
 977    --  GNAT, GNATPREP
 978    --  Set to True if symbols for preprocessing a source are to be listed
 979    --  before preprocessing occurs. Set to True by switch -s of gnatprep or
 980    --  -s in preprocessing data file for the compiler.
 981 
 982    type Create_Repinfo_File_Proc is access procedure (Src  : String);
 983    type Write_Repinfo_Line_Proc  is access procedure (Info : String);
 984    type Close_Repinfo_File_Proc  is access procedure;
 985    --  Types used for procedure addresses below
 986 
 987    Create_Repinfo_File_Access : Create_Repinfo_File_Proc := null;
 988    Write_Repinfo_Line_Access  : Write_Repinfo_Line_Proc  := null;
 989    Close_Repinfo_File_Access  : Close_Repinfo_File_Proc  := null;
 990    --  GNAT
 991    --  These three locations are left null when operating in non-compiler (e.g.
 992    --  ASIS mode), but when operating in compiler mode, they are set to point
 993    --  to the three corresponding procedures in Osint-C. The reason for this
 994    --  slightly strange interface is to stop Repinfo from dragging in Osint in
 995    --  ASIS mode, which would include lots of unwanted units in the ASIS build.
 996 
 997    type Create_List_File_Proc is access procedure (S : String);
 998    type Write_List_Info_Proc  is access procedure (S : String);
 999    type Close_List_File_Proc  is access procedure;
1000    --  Types used for procedure addresses below
1001 
1002    Create_List_File_Access : Create_List_File_Proc := null;
1003    Write_List_Info_Access  : Write_List_Info_Proc  := null;
1004    Close_List_File_Access  : Close_List_File_Proc  := null;
1005    --  GNAT
1006    --  These three locations are left null when operating in non-compiler
1007    --  (e.g. from the binder), but when operating in compiler mode, they are
1008    --  set to point to the three corresponding procedures in Osint-C. The
1009    --  reason for this slightly strange interface is to prevent Repinfo
1010    --  from dragging in Osint-C in the binder, which would include unwanted
1011    --  units in the binder.
1012 
1013    Locking_Policy : Character := ' ';
1014    --  GNAT, GNATBIND
1015    --  Set to ' ' for the default case (no locking policy specified). Reset to
1016    --  first character (uppercase) of locking policy name if a valid pragma
1017    --  Locking_Policy is encountered.
1018 
1019    Locking_Policy_Sloc : Source_Ptr := No_Location;
1020    --  GNAT, GNATBIND
1021    --  Remember location of previous Locking_Policy pragma. This is used for
1022    --  inconsistency error messages. A value of System_Location is used if the
1023    --  policy is set in package System.
1024 
1025    Look_In_Primary_Dir : Boolean := True;
1026    --  GNAT, GNATBIND, GNATMAKE, GNATCLEAN
1027    --  Set to False if a -I- was present on the command line. When True we are
1028    --  allowed to look in the primary directory to locate other source or
1029    --  library files.
1030 
1031    Make_Steps : Boolean := False;
1032    --  GNATMAKE
1033    --  Set to True when either Compile_Only, Bind_Only or Link_Only is
1034    --  set to True.
1035 
1036    Main_Index : Int := 0;
1037    --  GNATMAKE
1038    --  This is set to non-zero by gnatmake switch -eInnn to indicate that
1039    --  the main program is the nnn unit in a multi-unit source file.
1040 
1041    Mapping_File_Name : String_Ptr := null;
1042    --  GNAT
1043    --  File name of mapping between unit names, file names and path names.
1044    --  (given by switch -gnatem)
1045 
1046    Maximum_Messages : Int := 9999;
1047    --  GNAT, GNATBIND
1048    --  Maximum default number of errors before compilation is terminated, or in
1049    --  the case of GNAT, maximum number of warnings before further warnings are
1050    --  suppressed. Can be overridden by -gnatm (GNAT) or -m (GNATBIND) switch.
1051 
1052    Maximum_File_Name_Length : Int;
1053    --  GNAT, GNATBIND
1054    --  Maximum number of characters allowed in a file name, not counting the
1055    --  extension, as set by the appropriate switch. If no switch is given,
1056    --  then this value is initialized by Osint to the appropriate value.
1057 
1058    Maximum_Instantiations : Int := 8000;
1059    --  GNAT
1060    --  Maximum number of instantiations permitted (to stop runaway cases
1061    --  of nested instantiations). These situations probably only occur in
1062    --  specially concocted test cases. Can be modified by -gnateinn switch.
1063 
1064    Maximum_Processes : Positive := 1;
1065    --  GNATMAKE, GPRBUILD
1066    --  Maximum number of processes that should be spawned to carry out
1067    --  compilations.
1068 
1069    Minimal_Recompilation : Boolean := False;
1070    --  GNATMAKE
1071    --  Set to True if minimal recompilation mode requested
1072 
1073    Minimize_Expression_With_Actions : Boolean := False;
1074    --  GNAT
1075    --  If True, minimize the use of N_Expression_With_Actions node.
1076    --  This can be used in particular on some back-ends where this node is
1077    --  difficult to support.
1078 
1079    Modify_Tree_For_C : Boolean := False;
1080    --  GNAT
1081    --  If this switch is set True (currently it is set only by -gnatd.V), then
1082    --  certain meaning-preserving transformations are applied to the tree to
1083    --  make it easier to interface with back ends that implement C semantics.
1084    --  There is a section in Sinfo which describes the transformations made.
1085 
1086    Multiple_Unit_Index : Int := 0;
1087    --  GNAT
1088    --  This is set non-zero if the current unit is being compiled in multiple
1089    --  unit per file mode, meaning that the current unit is selected from the
1090    --  sequence of units in the current source file, using the value stored
1091    --  in this variable (e.g. 2 = select second unit in file). A value of
1092    --  zero indicates that we are in normal (one unit per file) mode.
1093 
1094    No_Backup : Boolean := False;
1095    --  GNATNAME
1096    --  Do not create backup copies of project files. Set by switch --no-backup.
1097 
1098    No_Deletion : Boolean := False;
1099    --  GNATPREP
1100    --  Set by preprocessor switch -a. Do not eliminate any source text. Implies
1101    --  Undefined_Symbols_Are_False. Useful to perform a syntax check on all
1102    --  branches of #if constructs.
1103 
1104    No_Elab_Code_All_Pragma : Node_Id := Empty;
1105    --  Set to point to a No_Elaboration_Code_All pragma or aspect encountered
1106    --  in the spec of the extended main unit. Used to determine if we need to
1107    --  do special tests for violation of this aspect.
1108 
1109    No_Main_Subprogram : Boolean := False;
1110    --  GNATMAKE, GNATBIND
1111    --  Set to True if compilation/binding of a program without main
1112    --  subprogram requested.
1113 
1114    No_Run_Time_Mode : Boolean := False;
1115    --  GNAT, GNATBIND
1116    --  This flag is set True if a No_Run_Time pragma is encountered. See spec
1117    --  of Rtsfind for a full description of handling of this pragma.
1118 
1119    No_Split_Units : Boolean := False;
1120    --  GPRBUILD
1121    --  Set to True with switch --no-split-units. When True, unit sources, spec,
1122    --  body and subunits, must all be in the same project. This is checked
1123    --  after each compilation.
1124 
1125    No_Stdinc : Boolean := False;
1126    --  GNAT, GNATBIND, GNATMAKE, GNATFIND, GNATXREF
1127    --  Set to True if no default source search dirs added to search list.
1128 
1129    No_Stdlib : Boolean := False;
1130    --  GNATMAKE, GNATBIND, GNATFIND, GNATXREF
1131    --  Set to True if no default library search dirs added to search list.
1132 
1133    No_Strict_Aliasing : Boolean := False;
1134    --  GNAT
1135    --  Set True if pragma No_Strict_Aliasing with no parameters encountered.
1136 
1137    No_Tagged_Streams : Node_Id := Empty;
1138    --  GNAT
1139    --  If a pragma No_Tagged_Streams is active for the current scope, this
1140    --  points to the corresponding pragma.
1141 
1142    Normalize_Scalars : Boolean := False;
1143    --  GNAT, GNATBIND
1144    --  Set True if a pragma Normalize_Scalars applies to the current unit.
1145    --  Note that Init_Or_Norm_Scalars is also set to True if this is True.
1146 
1147    Object_Directory_Present : Boolean := False;
1148    --  GNATMAKE
1149    --  Set to True when an object directory is specified with option -D
1150 
1151    Object_Path_File_Name : String_Ptr := null;
1152    --  GNAT2WHY
1153    --  Path of the temporary file that contains a list of object directories
1154    --  passed by -gnateO=<obj_path_file>.
1155 
1156    One_Compilation_Per_Obj_Dir : Boolean := False;
1157    --  GNATMAKE, GPRBUILD
1158    --  Set to True with switch --single-compile-per-obj-dir. When True, there
1159    --  cannot be simultaneous compilations with the object files in the same
1160    --  object directory, if project files are used.
1161 
1162    type Operating_Mode_Type is (Check_Syntax, Check_Semantics, Generate_Code);
1163    pragma Ordered (Operating_Mode_Type);
1164    Operating_Mode : Operating_Mode_Type := Generate_Code;
1165    --  GNAT
1166    --  Indicates the operating mode of the compiler. The default is generate
1167    --  code, which runs the parser, semantics and backend. Switches can be
1168    --  used to set syntax checking only mode, or syntax and semantics checking
1169    --  only mode. Operating_Mode can also be modified as a result of detecting
1170    --  errors during the compilation process. In particular if any serious
1171    --  error is detected then this flag is reset from Generate_Code to
1172    --  Check_Semantics after generating an error message. This is an ordered
1173    --  type with the semantics that each value does more than the previous one.
1174 
1175    Optimize_Alignment : Character := 'O';
1176    --  Setting of Optimize_Alignment, set to T/S/O for time/space/off. Can
1177    --  be modified by use of pragma Optimize_Alignment.
1178 
1179    Optimize_Alignment_Local : Boolean := False;
1180    --  Set True if Optimize_Alignment mode is set by a local configuration
1181    --  pragma that overrides the gnat.adc (or other configuration file) default
1182    --  so that the unit is not dependent on the default setting. Also always
1183    --  set True for internal units, since these always have a default setting
1184    --  of Optimize_Alignment (Off) that is enforced (essentially equivalent to
1185    --  them all having such an explicit pragma in each unit).
1186 
1187    Original_Operating_Mode : Operating_Mode_Type := Generate_Code;
1188    --  GNAT
1189    --  Indicates the original operating mode of the compiler as set by compiler
1190    --  options. This is identical to Operating_Mode except that this is not
1191    --  affected by errors.
1192 
1193    Optimization_Level : Int;
1194    pragma Import (C, Optimization_Level, "optimize");
1195    --  Constant reflecting the optimization level (0,1,2,3 for -O0,-O1,-O2,-O3)
1196 
1197    Optimize_Size : Int;
1198    pragma Import (C, Optimize_Size, "optimize_size");
1199    --  Constant reflecting setting of -Os (optimize for size). Set to nonzero
1200    --  in -Os mode and set to zero otherwise.
1201 
1202    Output_File_Name_Present : Boolean := False;
1203    --  GNATBIND, GNAT, GNATMAKE
1204    --  Set to True when the output C file name is given with option -o for
1205    --  GNATBIND, when the object file name is given with option -gnatO for GNAT
1206    --  or when the executable is given with option -o for GNATMAKE.
1207 
1208    Output_Linker_Option_List : Boolean := False;
1209    --  GNATBIND
1210    --  True if output of list of linker options is requested (-K switch set)
1211 
1212    Output_ALI_List   : Boolean := False;
1213    ALI_List_Filename : String_Ptr;
1214    --  GNATBIND
1215    --  True if output of list of ALIs is requested (-A switch set). List is
1216    --  output under the given filename, or standard output if not specified.
1217 
1218    Output_Object_List   : Boolean := False;
1219    Object_List_Filename : String_Ptr;
1220    --  GNATBIND
1221    --  True if output of list of objects is requested (-O switch set). List is
1222    --  output under the given filename, or standard output if not specified.
1223 
1224    Partition_Elaboration_Policy : Character := ' ';
1225    --  GNAT, GNATBIND
1226    --  Set to ' ' for the default case (no elaboration policy specified). Reset
1227    --  to first character (uppercase) of locking policy name if a valid pragma
1228    --  Partition_Elaboration_Policy is encountered.
1229 
1230    Partition_Elaboration_Policy_Sloc : Source_Ptr := No_Location;
1231    --  GNAT, GNATBIND
1232    --  Remember location of previous Partition_Elaboration_Policy pragma. This
1233    --  is used for inconsistency error messages. A value of System_Location is
1234    --  used if the policy is set in package System.
1235 
1236    Persistent_BSS_Mode : Boolean := False;
1237    --  GNAT
1238    --  True if a Persistent_BSS configuration pragma is in effect, causing
1239    --  potentially persistent data to be placed in the persistent_bss section.
1240 
1241    Pessimistic_Elab_Order : Boolean := False;
1242    --  GNATBIND
1243    --  True if pessimistic elaboration order is to be chosen (-p switch set)
1244 
1245    Polling_Required : Boolean := False;
1246    --  GNAT
1247    --  Set to True if polling for asynchronous abort is enabled by using
1248    --  the -gnatP option for GNAT.
1249 
1250    Prefix_Exception_Messages : Boolean := False;
1251    --  GNAT
1252    --  Set True to prefix exception messages with entity-name:
1253 
1254    Preprocessing_Data_File : String_Ptr := null;
1255    --  GNAT
1256    --  Set by switch -gnatep=. The file name of the preprocessing data file.
1257 
1258    Preprocessing_Symbol_Defs : String_List_Access := new String_List (1 .. 4);
1259    --  An extensible array to temporarily stores symbol definitions specified
1260    --  on the command line with -gnateD switches. The value 4 is an arbitrary
1261    --  starting point, if more space is needed it is allocated as required.
1262 
1263    Preprocessing_Symbol_Last : Natural := 0;
1264    --  Index of last symbol definition in array Symbol_Definitions
1265 
1266    Print_Generated_Code : Boolean := False;
1267    --  GNAT
1268    --  Set to True to enable output of generated code in source form. This
1269    --  flag is set by the -gnatG switch.
1270 
1271    Print_Standard : Boolean := False;
1272    --  GNAT
1273    --  Set to true to enable printing of package standard in source form.
1274    --  This flag is set by the -gnatS switch
1275 
1276    type Usage is (Unknown, Not_In_Use, In_Use);
1277    Project_File_In_Use : Usage := Unknown;
1278    --  GNAT
1279    --  Indicates if a project file is used or not. Set to In_Use by the first
1280    --  SFNP pragma.
1281 
1282    Queuing_Policy : Character := ' ';
1283    --  GNAT, GNATBIND
1284    --  Set to ' ' for the default case (no queuing policy specified). Reset to
1285    --  first character (uppercase) of locking policy name if a valid
1286    --  Queuing_Policy pragma is encountered.
1287 
1288    Queuing_Policy_Sloc : Source_Ptr := No_Location;
1289    --  GNAT, GNATBIND
1290    --  Remember location of previous Queuing_Policy pragma. This is used for
1291    --  inconsistency error messages. A value of System_Location is used if the
1292    --  policy is set in package System.
1293 
1294    Quiet_Output : Boolean := False;
1295    --  GNATMAKE, GNATCLEAN, GPRBUILD, GPRCLEAN
1296    --  Set to True if the tool should not have any output if there are no
1297    --  errors or warnings.
1298 
1299    Overriding_Renamings : Boolean := False;
1300    --  GNAT
1301    --  Set to True to enable compatibility mode with Rational compiler, and
1302    --  to accept renamings of implicit operations in their own scope.
1303 
1304    Relaxed_RM_Semantics : Boolean := False;
1305    --  GNAT
1306    --  Set to True to ignore some Ada semantic error to help parse legacy Ada
1307    --  code for use in e.g. static analysis (such as CodePeer). This deals
1308    --  with cases where other compilers allow illegal constructs. Tools such as
1309    --  CodePeer are interested in analyzing code rather than enforcing legality
1310    --  rules, so as long as these illegal constructs end up with code that can
1311    --  be handled by the tool in question, there is no reason to reject the
1312    --  code that is considered correct by the other compiler.
1313 
1314    Replace_In_Comments : Boolean := False;
1315    --  GNATPREP
1316    --  Set to True if -C switch used.
1317 
1318    RTS_Lib_Path_Name : String_Ptr := null;
1319    RTS_Src_Path_Name : String_Ptr := null;
1320    --  GNAT
1321    --  Set to the "adalib" and "adainclude" directories of the run time
1322    --  specified by --RTS=.
1323 
1324    RTS_Switch : Boolean := False;
1325    --  GNAT, GNATMAKE, GNATBIND, GNATLS, GNATFIND, GNATXREF
1326    --  Set to True when the --RTS switch is set
1327 
1328    Run_Path_Option : Boolean := True;
1329    --  GNATMAKE, GNATLINK
1330    --  Set to False when no run_path_option should be issued to the linker
1331 
1332    Search_Directory_Present : Boolean := False;
1333    --  GNAT
1334    --  Set to True when argument is -I. Reset to False when next argument, a
1335    --  search directory path is taken into account. Note that this is quite
1336    --  different from other switches in this section in that it is only set in
1337    --  a transitory manner as a result of scanning a -I switch with no file
1338    --  name, and if set, is an indication that the next argument is to be
1339    --  treated as a file name.
1340 
1341    Sec_Stack_Used : Boolean := False;
1342    --  GNAT, GBATBIND
1343    --  Set True if generated code uses the System.Secondary_Stack package. For
1344    --  the binder, set if any unit uses the secondary stack package.
1345 
1346    Setup_Projects : Boolean := False;
1347    --  GNAT DRIVER
1348    --  Set to True for GNAT SETUP: the Project Manager creates nonexistent
1349    --  object, library, and exec directories.
1350 
1351    Shared_Libgnat : Boolean;
1352    --  GNATBIND
1353    --  Set to True if a shared libgnat is requested by using the -shared option
1354    --  for GNATBIND and to False when using the -static option. The value of
1355    --  this flag is set by Gnatbind.Scan_Bind_Arg.
1356 
1357    Short_Circuit_And_Or : Boolean := False;
1358    --  GNAT
1359    --  Set True if a pragma Short_Circuit_And_Or applies to the current unit.
1360 
1361    type SPARK_Mode_Type is (None, Off, On);
1362    --  Possible legal modes that can be set by aspect/pragma SPARK_Mode, as
1363    --  well as the value None, which indicates no such pragma/aspect applies.
1364 
1365    SPARK_Mode : SPARK_Mode_Type := None;
1366    --  GNAT
1367    --  Current SPARK mode setting.
1368 
1369    SPARK_Mode_Pragma : Node_Id := Empty;
1370    --  GNAT
1371    --  If the current SPARK_Mode (above) was set by a pragma, this records
1372    --  the pragma that set this mode.
1373 
1374    SPARK_Switches_File_Name : String_Ptr := null;
1375    --  GNAT
1376    --  Set to non-null file name by use of the -gnates switch to specify
1377    --  SPARK (gnat2why) specific switches in the given file name.
1378 
1379    Special_Exception_Package_Used : Boolean := False;
1380    --  GNAT
1381    --  Set to True if either of the unit GNAT.Most_Recent_Exception or
1382    --  GNAT.Exception_Traces is with'ed. Used to inhibit transformation of
1383    --  local raise statements into gotos in the presence of either package.
1384 
1385    Sprint_Line_Limit : Nat := 72;
1386    --  GNAT
1387    --  Limit values for chopping long lines in Cprint/Sprint output, can be
1388    --  reset by use of NNN parameter with -gnatG or -gnatD switches.
1389 
1390    Stack_Checking_Enabled : Boolean := False;
1391    --  GNAT
1392    --  Set to indicate if stack checking is enabled for the compilation. This
1393    --  is set directly from the value in the gcc back end in the body of the
1394    --  gcc version of back_end.adb.
1395 
1396    Style_Check : Boolean := False;
1397    --  GNAT
1398    --  Set True to perform style checks. Activates checks carried out in
1399    --  package Style (see body of this package for details of checks). This
1400    --  flag is set True by use of either the -gnatg or -gnaty switches, or
1401    --  by the Style_Check pragma.
1402 
1403    Style_Check_Main : Boolean := False;
1404    --  GNAT
1405    --  Set True if Style_Check was set for the main unit. This is used to
1406    --  enable style checks for units in the main extended source that get
1407    --  with'ed indirectly. It is set True by use of either the -gnatg or
1408    --  -gnaty switches, but not by use of the Style_Checks pragma.
1409 
1410    Disable_FE_Inline        : Boolean := False;
1411    Disable_FE_Inline_Always : Boolean := False;
1412    --  GNAT
1413    --  Request to disable front end inlining from pragma Inline or pragma
1414    --  Inline_Always out of the presence of the -fno-inline back end flag
1415    --  on the command line, regardless of any other switches that are set.
1416    --  It remains the back end's reponsibility to honor -fno-inline at the
1417    --  back end level.
1418 
1419    Suppress_Control_Flow_Optimizations : Boolean := False;
1420    --  GNAT
1421    --  Set by -fpreserve-control-flow. Suppresses control flow optimizations
1422    --  that interfere with coverage analysis based on the object code.
1423 
1424    System_Extend_Pragma_Arg : Node_Id := Empty;
1425    --  GNAT
1426    --  Set non-empty if and only if a correct Extend_System pragma was present
1427    --  in which case it points to the argument of the pragma, and the name can
1428    --  be located as Chars (Expression (System_Extend_Pragma_Arg)).
1429 
1430    System_Extend_Unit : Node_Id := Empty;
1431    --  GNAT
1432    --  This is set to Empty if GNAT_Mode is set, since pragma Extend_System
1433    --  is never appropriate in GNAT_Mode (and causes troubles, including
1434    --  bogus circularities, if we try to compile the run-time library with
1435    --  a System extension). If GNAT_Mode is not set, then System_Extend_Unit
1436    --  is a copy of the value set in System_Extend_Pragma_Arg.
1437 
1438    Subunits_Missing : Boolean := False;
1439    --  GNAT
1440    --  This flag is set true if missing subunits are detected with code
1441    --  generation active. This causes code generation to be skipped.
1442 
1443    Suppress_Checks : Boolean := False;
1444    --  GNAT
1445    --  Set to True if -gnatp (suppress all checks) switch present.
1446 
1447    Suppress_Options : Suppress_Record;
1448    --  GNAT
1449    --  Indicates outer level setting of check suppression. This initializes
1450    --  the settings of the outer scope level in any unit compiled. This is
1451    --  initialized by Osint.Initialize, and further initialized by the
1452    --  Adjust_Global_Switches flag in Gnat1drv.
1453 
1454    Table_Factor : Int := 1;
1455    --  GNAT
1456    --  Factor by which all initial table sizes set in Alloc are multiplied.
1457    --  Used in Table to calculate initial table sizes (the initial table size
1458    --  is the value in Alloc, used as the Table_Initial parameter value,
1459    --  multiplied by the factor given here. The default value is used if no
1460    --  -gnatT switch appears.
1461 
1462    Tagged_Type_Expansion : Boolean := True;
1463    --  GNAT
1464    --  Set True if tagged types and interfaces should be expanded by the
1465    --  front-end. If False, the original tree is left unexpanded for tagged
1466    --  types and dispatching calls, assuming the underlying target supports it.
1467 
1468    Target_Dependent_Info_Read_Name : String_Ptr := null;
1469    --  GNAT
1470    --  Set non-null to override the normal processing in Get_Targ and set the
1471    --  necessary information by reading the target dependent information file
1472    --  whose name is given here (see packages Get_Targ and Set_Targ for full
1473    --  details). Set to non-null file name by use of the -gnateT switch.
1474 
1475    Target_Dependent_Info_Write_Name : String_Ptr := null;
1476    --  GNAT
1477    --  Set non-null to enable a call to Set_Targ.Write_Target_Dependent_Info
1478    --  which writes a target independent information file (see packages
1479    --  Get_Targ and Set_Targ for full details) using the name given by
1480    --  this switch. Set to non-null file name by use of the -gnatet switch.
1481 
1482    type Origin_Of_Target is (Unknown, Default, Specified);
1483 
1484    Target_Origin : Origin_Of_Target := Unknown;
1485    --  GPRBUILD
1486    --  Indicates the origin of attribute Target in project files
1487 
1488    Target_Value : String_Access := null;
1489    --  GPRBUILD
1490    --  Indicates the value of attribute Target in project files
1491 
1492    Task_Dispatching_Policy : Character := ' ';
1493    --  GNAT, GNATBIND
1494    --  Set to ' ' for the default case (no task dispatching policy specified).
1495    --  Reset to first character (uppercase) of task dispatching policy name
1496    --  if a valid Task_Dispatching_Policy pragma is encountered.
1497 
1498    Task_Dispatching_Policy_Sloc : Source_Ptr := No_Location;
1499    --  GNAT, GNATBIND
1500    --  Remember location of previous Task_Dispatching_Policy pragma. This is
1501    --  used for inconsistency error messages. A value of System_Location is
1502    --  used if the policy is set in package System.
1503 
1504    Tasking_Used : Boolean := False;
1505    --  Set True if any tasking construct is encountered. Used to activate the
1506    --  output of the Q, L and T lines in ALI files.
1507 
1508    Time_Slice_Set : Boolean := False;
1509    --  GNATBIND
1510    --  Set True if a pragma Time_Slice is processed in the main unit, or
1511    --  if the -gnatTnn switch is present to set a time slice value.
1512 
1513    Time_Slice_Value : Nat;
1514    --  GNATBIND
1515    --  Time slice value. Valid only if Time_Slice_Set is True, i.e. if
1516    --  Time_Slice pragma has been processed. Set to the time slice value in
1517    --  microseconds. Negative values are stored as zero, and the value is not
1518    --  larger than 1_000_000_000 (1000 seconds). Values larger than this are
1519    --  reset to this maximum. This can also be set with the -gnatTnn switch.
1520 
1521    Tolerate_Consistency_Errors : Boolean := False;
1522    --  GNATBIND
1523    --  Tolerate time stamp and other consistency errors. If this flag is set to
1524    --  True (-t), then inconsistencies result in warnings rather than errors.
1525 
1526    Treat_Categorization_Errors_As_Warnings : Boolean := False;
1527    --  Normally categorization errors are true illegalities. If this switch
1528    --  is set, then such errors result in warning messages rather than error
1529    --  messages. Set True by -gnateP (P for Pure/Preelaborate). Also set in
1530    --  Relaxed_RM_Semantics mode since some old Ada 83 compilers treated
1531    --  pragma Preelaborate differently.
1532 
1533    Treat_Restrictions_As_Warnings : Boolean := False;
1534    --  GNAT
1535    --  Set True to treat pragma Restrictions as Restriction_Warnings. Set by
1536    --  -gnatr switch.
1537 
1538    Tree_Output : Boolean := False;
1539    --  GNAT
1540    --  Set to True (-gnatt) to generate output tree file
1541 
1542    Try_Semantics : Boolean := False;
1543    --  GNAT
1544    --  Flag set to force attempt at semantic analysis, even if parser errors
1545    --  occur. This will probably cause blowups at this stage in the game. On
1546    --  the other hand, most such blowups will be caught cleanly and simply
1547    --  say compilation abandoned. This flag is set True by -gnatq or -gnatQ.
1548 
1549    Unchecked_Shared_Lib_Imports : Boolean := False;
1550    --  GPRBUILD
1551    --  Set to True when shared library projects are allowed to import projects
1552    --  that are not shared library projects. Set on by use of the switch
1553    --  --unchecked-shared-lib-imports.
1554 
1555    Undefined_Symbols_Are_False : Boolean := False;
1556    --  GNAT, GNATPREP
1557    --  Set to True by switch -u of gnatprep or -u in the preprocessing data
1558    --  file for the compiler. Indicates that while preprocessing sources,
1559    --  symbols that are not defined have the value FALSE.
1560 
1561    Uneval_Old : Character := 'E';
1562    --  GNAT
1563    --  Set to 'E'/'W'/'A' for use of Error/Warn/Allow in a valid pragma
1564    --  Unevaluated_Use_Of_Old. Default in the absence of the pragma is 'E'
1565    --  for the RM default behavior of giving an error.
1566 
1567    Unique_Error_Tag : Boolean := Tag_Errors;
1568    --  GNAT
1569    --  Indicates if error messages are to be prefixed by the string error:
1570    --  Initialized from Tag_Errors, can be forced on with the -gnatU switch.
1571 
1572    Unnest_Subprogram_Mode : Boolean := False;
1573    --  If true, activates the circuitry for unnesting subprograms (see the spec
1574    --  of Exp_Unst for full details). Currently set only by use of -gnatd.1.
1575 
1576    Unreserve_All_Interrupts : Boolean := False;
1577    --  GNAT, GNATBIND
1578    --  Normally set False, set True if a valid Unreserve_All_Interrupts pragma
1579    --  appears anywhere in the main unit for GNAT, or if any ALI file has the
1580    --  corresponding attribute set in GNATBIND.
1581 
1582    Upper_Half_Encoding : Boolean := False;
1583    --  GNAT, GNATBIND
1584    --  Normally set False, indicating that upper half ISO 8859-1 characters are
1585    --  used in the normal way to represent themselves. If the wide character
1586    --  encoding method uses the upper bit for this encoding, then this flag is
1587    --  set True, and upper half characters in the source indicate the start of
1588    --  a wide character sequence. Set by -gnatW or -W switches.
1589 
1590    Use_Include_Path_File : Boolean := False;
1591    --  GNATMAKE, GPRBUILD
1592    --  When True, create a source search path file, even when a mapping file
1593    --  is used.
1594 
1595    Usage_Requested : Boolean := False;
1596    --  GNAT, GNATBIND, GNATMAKE
1597    --  Set to True if -h (-gnath for the compiler) switch encountered
1598    --  requesting usage information
1599 
1600    Use_Pragma_Linker_Constructor : Boolean := False;
1601    --  GNATBIND
1602    --  True if pragma Linker_Constructor applies to adainit
1603 
1604    Use_VADS_Size : Boolean := False;
1605    --  GNAT
1606    --  Set to True if a valid pragma Use_VADS_Size is processed
1607 
1608    Validity_Checks_On  : Boolean := True;
1609    --  GNAT
1610    --  This flag determines if validity checking is on or off. The initial
1611    --  state is on, and the required default validity checks are active. The
1612    --  actual set of checks that is performed if Validity_Checks_On is set is
1613    --  defined by the switches in package Validsw. The Validity_Checks_On flag
1614    --  is controlled by pragma Validity_Checks (On | Off), and also some
1615    --  generated compiler code (typically code that has to do with validity
1616    --  check generation) is compiled with this flag set to False. This flag is
1617    --  set to False by the -gnatp switch.
1618 
1619    Verbose_Mode : Boolean := False;
1620    --  GNAT, GNATBIND, GNATMAKE, GNATLINK, GNATLS, GNATNAME, GNATCLEAN,
1621    --  GPRBUILD, GPRCLEAN
1622    --  Set to True to get verbose mode (full error message text and location
1623    --  information sent to standard output, also header, copyright and summary)
1624 
1625    type Verbosity_Level_Type is (None, Low, Medium, High);
1626    pragma Ordered (Verbosity_Level_Type);
1627    Verbosity_Level : Verbosity_Level_Type := High;
1628    --  GNATMAKE
1629    --  Modified by gnatmake switches -v, -vl, -vm, -vh. Indicates
1630    --  the level of verbosity of informational messages:
1631    --
1632    --  In Low Verbosity, the reasons why a source is recompiled, the name
1633    --  of the executable and the reason it must be rebuilt is output.
1634    --
1635    --  In Medium Verbosity, additional lines are output for each ALI file
1636    --  that is checked.
1637    --
1638    --  In High Verbosity, additional lines are output when the ALI file
1639    --  is part of an Ada library, is read-only or is part of the runtime.
1640 
1641    Warn_On_Ada_2005_Compatibility : Boolean := True;
1642    --  GNAT
1643    --  Set to True to generate all warnings on Ada 2005 compatibility issues,
1644    --  including warnings on Ada 2005 obsolescent features used in Ada 2005
1645    --  mode. Set by default, modified by use of -gnatwy/Y.
1646 
1647    Warn_On_Ada_2012_Compatibility : Boolean := True;
1648    --  GNAT
1649    --  Set to True to generate all warnings on Ada 2012 compatibility issues,
1650    --  including warnings on Ada 2012 obsolescent features used in Ada 2012
1651    --  mode. Modified by use of -gnatwy/Y.
1652 
1653    Warn_On_All_Unread_Out_Parameters : Boolean := False;
1654    --  GNAT
1655    --  Set to True to generate warnings in all cases where a variable is
1656    --  modified by being passed as to an OUT formal, but the resulting value is
1657    --  never read. The default is that this warning is suppressed. Modified
1658    --  by use of gnatw.o/.O.
1659 
1660    Warn_On_Assertion_Failure : Boolean := True;
1661    --  GNAT
1662    --  Set to True to activate warnings on assertions that can be determined
1663    --  at compile time will always fail. Modified by use of -gnatw.a/.A.
1664 
1665    Warn_On_Assumed_Low_Bound : Boolean := True;
1666    --  GNAT
1667    --  Set to True to activate warnings for string parameters that are indexed
1668    --  with literals or S'Length, presumably assuming a lower bound of one.
1669    --  Modified by use of -gnatww/W.
1670 
1671    Warn_On_Atomic_Synchronization : Boolean := False;
1672    --  GNAT
1673    --  Set to True to generate information messages for atomic synchronization.
1674    --  Modified by use of -gnatw.n/.N.
1675 
1676    Warn_On_Bad_Fixed_Value : Boolean := False;
1677    --  GNAT
1678    --  Set to True to generate warnings for static fixed-point expression
1679    --  values that are not an exact multiple of the small value of the type.
1680    --  Odd by default, modified by use of -gnatwb/B.
1681 
1682    Warn_On_Biased_Representation : Boolean := True;
1683    --  GNAT
1684    --  Set to True to generate warnings for size clauses, component clauses
1685    --  and component_size clauses that force biased representation. Modified
1686    --  by use of -gnatw.b/.B.
1687 
1688    Warn_On_Constant : Boolean := False;
1689    --  GNAT
1690    --  Set to True to generate warnings for variables that could be declared
1691    --  as constants. Modified by use of -gnatwk/K.
1692 
1693    Warn_On_Deleted_Code : Boolean := False;
1694    --  GNAT
1695    --  Set to True to generate warnings for code deleted by the front end
1696    --  for conditional statements whose outcome is known at compile time.
1697    --  Modified by use of -gnatwt/T.
1698 
1699    Warn_On_Dereference : Boolean := False;
1700    --  GNAT
1701    --  Set to True to generate warnings for implicit dereferences for array
1702    --  indexing and record component access. Modified by use of -gnatwd/D.
1703 
1704    Warn_On_Export_Import : Boolean := True;
1705    --  GNAT
1706    --  Set to True to generate warnings for suspicious use of export or
1707    --  import pragmas. Modified by use of -gnatwx/X.
1708 
1709    Warn_On_Elab_Access : Boolean := False;
1710    --  GNAT
1711    --  Set to True to generate warnings for P'Access in the case where
1712    --  subprogram P is in the same package as the P'Access, and the P'Access is
1713    --  evaluated at package elaboration time, and occurs before the body of P
1714    --  has been elaborated.
1715 
1716    Warn_On_Hiding : Boolean := False;
1717    --  GNAT
1718    --  Set to True to generate warnings if a declared entity hides another
1719    --  entity. The default is that this warning is suppressed. Modified by
1720    --  use of -gnatwh/H.
1721 
1722    Warn_On_Modified_Unread : Boolean := False;
1723    --  GNAT
1724    --  Set to True to generate warnings if a variable is assigned but is never
1725    --  read. Also controls warnings for similar cases involving out parameters,
1726    --  but only if there is only one out parameter for the procedure involved.
1727    --  The default is that this warning is suppressed, modified by use of
1728    --  -gnatwm/M.
1729 
1730    Warn_On_No_Value_Assigned : Boolean := True;
1731    --  GNAT
1732    --  Set to True to generate warnings if no value is ever assigned to a
1733    --  variable that is at least partially uninitialized. Set to false to
1734    --  suppress such warnings. The default is that such warnings are enabled.
1735    --  Modified by use of -gnatwv/V.
1736 
1737    Warn_On_Non_Local_Exception : Boolean := False;
1738    --  GNAT
1739    --  Set to True to generate warnings for non-local exception raises and also
1740    --  handlers that can never handle a local raise. This warning is only ever
1741    --  generated if pragma Restrictions (No_Exception_Propagation) is set. The
1742    --  default is not to generate the warnings except that if the source has
1743    --  at least one exception handler, and this restriction is set, and the
1744    --  warning was not explicitly turned off, then it is turned on by default.
1745    --  Modified by use of -gnatw.x/.X.
1746 
1747    No_Warn_On_Non_Local_Exception : Boolean := False;
1748    --  GNAT
1749    --  This is set to True if the above warning is explicitly suppressed. We
1750    --  use this to avoid turning it on by default when No_Exception_Propagation
1751    --  restriction is set and an exception handler is present.
1752 
1753    Warn_On_Object_Renames_Function : Boolean := False;
1754    --  GNAT
1755    --  Set to True to generate warnings when a function result is renamed as
1756    --  an object. The default is that this warning is disabled. Modified by
1757    --  use of -gnatw.r/.R.
1758 
1759    Warn_On_Obsolescent_Feature : Boolean := False;
1760    --  GNAT
1761    --  Set to True to generate warnings on use of any feature in Annex or if a
1762    --  subprogram is called for which a pragma Obsolescent applies. Modified
1763    --  by use of -gnatwj/J.
1764 
1765    Warn_On_Overlap : Boolean := False;
1766    --  GNAT
1767    --  Set to True to generate warnings when a writable actual overlaps with
1768    --  another actual in a subprogram call. This applies only in modes before
1769    --  Ada 2012. Starting with Ada 2012, such overlaps are illegal.
1770    --  Modified by use of -gnatw.i/.I.
1771 
1772    Warn_On_Questionable_Missing_Parens : Boolean := True;
1773    --  GNAT
1774    --  Set to True to generate warnings for cases where parentheses are missing
1775    --  and the usage is questionable, because the intent is unclear. On by
1776    --  default, modified by use of -gnatwq/Q.
1777 
1778    Warn_On_Parameter_Order : Boolean := False;
1779    --  GNAT
1780    --  Set to True to generate warnings for cases where the argument list for
1781    --  a call is a sequence of identifiers that match the formal identifiers,
1782    --  but are in the wrong order.
1783 
1784    Warn_On_Redundant_Constructs : Boolean := False;
1785    --  GNAT
1786    --  Set to True to generate warnings for redundant constructs (e.g. useless
1787    --  assignments/conversions). The default is that this warning is disabled.
1788    --  Modified by use of -gnatwr/R.
1789 
1790    Warn_On_Reverse_Bit_Order : Boolean := True;
1791    --  GNAT
1792    --  Set to True to generate warning (informational) messages for component
1793    --  clauses that are affected by non-standard bit-order. The default is
1794    --  that this warning is enabled. Modified by -gnatw.v/.V.
1795 
1796    Warn_On_Suspicious_Contract : Boolean := True;
1797    --  GNAT
1798    --  Set to True to generate warnings for suspicious contracts expressed as
1799    --  pragmas or aspects precondition and postcondition, as well as other
1800    --  suspicious cases of expressions typically found in contracts like
1801    --  quantified expressions and uses of Update attribute. The default is that
1802    --  this warning is enabled. Modified by use of -gnatw.t/.T.
1803 
1804    Warn_On_Suspicious_Modulus_Value : Boolean := True;
1805    --  GNAT
1806    --  Set to True to generate warnings for suspicious modulus values. The
1807    --  default is that this warning is enabled. Modified by -gnatw.m/.M.
1808 
1809    Warn_On_Unchecked_Conversion : Boolean := True;
1810    --  GNAT
1811    --  Set to True to generate warnings for unchecked conversions that may have
1812    --  non-portable semantics (e.g. because sizes of types differ). Modified
1813    --  by use of -gnatwz/Z.
1814 
1815    Warn_On_Unordered_Enumeration_Type : Boolean := False;
1816    --  GNAT
1817    --  Set to True to generate warnings for inappropriate uses (comparisons
1818    --  and explicit ranges) on unordered enumeration types (which includes
1819    --  all enumeration types for which pragma Ordered is not given). The
1820    --  default is that this warning is disabled. Modified by -gnat.u/.U.
1821 
1822    Warn_On_Unrecognized_Pragma : Boolean := True;
1823    --  GNAT
1824    --  Set to True to generate warnings for unrecognized pragmas. The default
1825    --  is that this warning is enabled. Modified by use of -gnatwg/G.
1826 
1827    Warn_On_Unrepped_Components : Boolean := False;
1828    --  GNAT
1829    --  Set to True to generate warnings for the case of components of record
1830    --  which have a record representation clause but this component does not
1831    --  have a component clause. Modified by use of -gnatw.c/.C.
1832 
1833    Warn_On_Warnings_Off : Boolean := False;
1834    --  GNAT
1835    --  Set to True to generate warnings for use of Pragma Warnings (Off, ent),
1836    --  where either the pragma is never used, or it could be replaced by a
1837    --  pragma Unmodified or Unreferenced. Also generates warnings for pragma
1838    --  Warning (Off, string) which either has no matching pragma Warning On,
1839    --  or where no warning has been suppressed by the use of the pragma.
1840    --  Modified by use of -gnatw.w/.W.
1841 
1842    type Warning_Mode_Type is (Suppress, Normal, Treat_As_Error);
1843    Warning_Mode : Warning_Mode_Type := Normal;
1844    --  GNAT, GNATBIND
1845    --  Controls treatment of warning messages. If set to Suppress, warning
1846    --  messages are not generated at all. In Normal mode, they are generated
1847    --  but do not count as errors. In Treat_As_Error mode, warning messages are
1848    --  generated and are treated as errors. Note that Warning_Mode = Suppress
1849    --  causes pragma Warnings to be ignored (except for legality checks),
1850    --  unless we are in GNATprove_Mode, which requires pragma Warnings to
1851    --  be stored for the formal verification backend.
1852 
1853    Warnings_As_Errors_Count : Natural;
1854    --  GNAT
1855    --  Number of entries stored in Warnings_As_Errors table
1856 
1857    Wide_Character_Encoding_Method : WC_Encoding_Method := WCEM_Brackets;
1858    --  GNAT, GNATBIND
1859    --  Method used for encoding wide characters in the source program. See
1860    --  description of type in unit System.WCh_Con for a list of the methods
1861    --  that are currently supported. Note that brackets notation is always
1862    --  recognized in source programs regardless of the setting of this
1863    --  variable. The default setting causes only the brackets notation to be
1864    --  recognized. If this is the main unit, this setting also controls the
1865    --  output of the W=? parameter in the ALI file, which is used to provide
1866    --  the default for encoding [Wide_[Wide_]]Text_IO files. For the binder,
1867    --  the value set here overrides this main unit default.
1868 
1869    Wide_Character_Encoding_Method_Specified : Boolean := False;
1870    --  GNAT, GNATBIND
1871    --  Set True if the value in Wide_Character_Encoding_Method was set as
1872    --  a result of an explicit -gnatW? or -W? switch. False otherwise.
1873 
1874    Xref_Active : Boolean := True;
1875    --  GNAT
1876    --  Set if cross-referencing is enabled (i.e. xref info in ALI files)
1877 
1878    Zero_Formatting : Boolean := False;
1879    --  GNATBIND
1880    --  Do no formatting (no title, no leading spaces, no empty lines) in
1881    --  auxiliary outputs (-e, -K, -l, -R).
1882 
1883    ----------------------------
1884    -- Configuration Settings --
1885    ----------------------------
1886 
1887    --  These are settings that are used to establish the mode at the start of
1888    --  each unit. The values defined below can be affected either by command
1889    --  line switches, or by the use of appropriate configuration pragmas in a
1890    --  configuration pragma file (but NOT by a local use of a configuration
1891    --  pragma in a single file).
1892 
1893    Ada_Version_Config : Ada_Version_Type;
1894    --  GNAT
1895    --  This is the value of the configuration switch for the Ada 83 mode, as
1896    --  set by the command line switches -gnat83/95/2005/2012, and possibly
1897    --  modified by the use of configuration pragmas Ada_*. This switch is used
1898    --  to set the initial value for Ada_Version mode at the start of analysis
1899    --  of a unit.  Note however that the setting of this flag is ignored for
1900    --  internal and predefined units (which are always compiled in the most up
1901    --  to date version of Ada).
1902 
1903    Ada_Version_Pragma_Config : Node_Id;
1904    --  This will be set nonempty if it is set by a configuration pragma
1905 
1906    Ada_Version_Explicit_Config : Ada_Version_Type;
1907    --  GNAT
1908    --  This is set in the same manner as Ada_Version_Config. The difference is
1909    --  that the setting of this flag is not ignored for internal and predefined
1910    --  units, which for some purposes do indeed access this value, regardless
1911    --  of the fact that they are compiled the most up to date ada version).
1912 
1913    Assertions_Enabled_Config : Boolean;
1914    --  GNAT
1915    --  This is the value of the configuration switch for assertions enabled
1916    --  mode, as possibly set by the command line switch -gnata, and possibly
1917    --  modified by the use of the configuration pragma Assertion_Policy.
1918 
1919    Assume_No_Invalid_Values_Config : Boolean;
1920    --  GNAT
1921    --  This is the value of the configuration switch for assuming "no invalid
1922    --  values enabled" mode, as possibly set by the command line switch
1923    --  -gnatB, and possibly modified by the use of the configuration pragma
1924    --  Assume_No_Invalid_Values.
1925 
1926    Check_Float_Overflow_Config : Boolean;
1927    --  GNAT
1928    --  Set to True to check that operations on predefined unconstrained float
1929    --  types (e.g. Float, Long_Float) do not overflow and generate infinities
1930    --  or invalid values. Set by the Check_Float_Overflow pragma, or by use
1931    --  of the -gnateF switch.
1932 
1933    Check_Policy_List_Config : Node_Id;
1934    --  GNAT
1935    --  This points to the list of N_Pragma nodes for Check_Policy pragmas
1936    --  that are linked through the Next_Pragma fields, with the list being
1937    --  terminated by Empty. The order is most recently processed first. This
1938    --  list includes only those pragmas in configuration pragma files.
1939 
1940    Default_Pool_Config : Node_Id := Empty;
1941    --  GNAT
1942    --  Same as Default_Pool above, except this is only for Default_Storage_Pool
1943    --  pragmas that are configuration pragmas.
1944 
1945    Default_SSO_Config : Character := ' ';
1946    --  GNAT
1947    --  Set if a pragma Default_Scalar_Storage_Order appears as a configuration
1948    --  pragma. A value of ' ' means that no pragma was given, otherwise the
1949    --  value is 'H' for High_Order_First or 'L' for Low_Order_First.
1950 
1951    Dynamic_Elaboration_Checks_Config : Boolean := False;
1952    --  GNAT
1953    --  Set True for dynamic elaboration checking mode, as set by the -gnatE
1954    --  switch or by the use of pragma Elaboration_Checking (Dynamic).
1955 
1956    Exception_Locations_Suppressed_Config : Boolean := False;
1957    --  GNAT
1958    --  Set True by use of the configuration pragma Suppress_Exception_Messages
1959 
1960    Extensions_Allowed_Config : Boolean;
1961    --  GNAT
1962    --  This is the flag that indicates whether extensions are allowed. It can
1963    --  be set True either by use of the -gnatX switch, or by use of the
1964    --  configuration pragma Extensions_Allowed (On). It is always set to True
1965    --  for internal GNAT units, since extensions are always permitted in such
1966    --  units.
1967 
1968    External_Name_Exp_Casing_Config : External_Casing_Type;
1969    --  GNAT
1970    --  This is the value of the configuration switch that controls casing of
1971    --  external symbols for which an explicit external name is given. It can be
1972    --  set to Uppercase by the command line switch -gnatF, and further modified
1973    --  by the use of the configuration pragma External_Name_Casing in the
1974    --  gnat.adc file. This flag is used to set the initial value for
1975    --  External_Name_Exp_Casing at the start of analyzing each unit. Note
1976    --  however that the setting of this flag is ignored for internal and
1977    --  predefined units (which are always compiled with As_Is mode).
1978 
1979    External_Name_Imp_Casing_Config : External_Casing_Type;
1980    --  GNAT
1981    --  This is the value of the configuration switch that controls casing of
1982    --  external symbols where the external name is implicitly given. It can be
1983    --  set to Uppercase by the command line switch -gnatF, and further modified
1984    --  by the use of the configuration pragma External_Name_Casing in the
1985    --  gnat.adc file. This flag is used to set the initial value for
1986    --  External_Name_Imp_Casing at the start of analyzing each unit. Note
1987    --  however that the setting of this flag is ignored for internal and
1988    --  predefined units (which are always compiled with Lowercase mode).
1989 
1990    Fast_Math_Config : Boolean;
1991    --  GNAT
1992    --  This is the value of the configuration switch that controls Fast_Math
1993    --  mode, as set by a Fast_Math pragma in configuration pragmas. It is
1994    --  used to set the initial value of Fast_Math at the start of each new
1995    --  compilation unit.
1996 
1997    Initialize_Scalars_Config : Boolean;
1998    --  GNAT
1999    --  This is the value of the configuration switch that is set by the
2000    --  pragma Initialize_Scalars when it appears in the gnat.adc file.
2001    --  This switch is not set when the pragma appears ahead of a given
2002    --  unit, so it does not affect the compilation of other units.
2003 
2004    No_Exit_Message : Boolean := False;
2005    --  GNATMAKE, GPRBUILD
2006    --  Set with switch --no-exit-message. When True, if there are compilation
2007    --  failures, the builder does not issue an exit error message.
2008 
2009    Optimize_Alignment_Config : Character;
2010    --  GNAT
2011    --  This is the value of the configuration switch that controls the
2012    --  alignment optimization mode, as set by an Optimize_Alignment pragma.
2013    --  It is used to set the initial value of Optimize_Alignment at the start
2014    --  of each new compilation unit, except that it is always set to 'O' (off)
2015    --  for internal units.
2016 
2017    Persistent_BSS_Mode_Config : Boolean;
2018    --  GNAT
2019    --  This is the value of the configuration switch that controls whether
2020    --  potentially persistent data is to be placed in the persistent_bss
2021    --  section. It can be set True by use of the pragma Persistent_BSS.
2022    --  This flag is used to set the initial value of Persistent_BSS_Mode
2023    --  at the start of each compilation unit, except that it is always
2024    --  set False for predefined units.
2025 
2026    Polling_Required_Config : Boolean;
2027    --  GNAT
2028    --  This is the value of the configuration switch that controls polling
2029    --  mode. It can be set True by the command line switch -gnatP, and then
2030    --  further modified by the use of pragma Polling in the gnat.adc file. This
2031    --  flag is used to set the initial value for Polling_Required at the start
2032    --  of analyzing each unit.
2033 
2034    Prefix_Exception_Messages_Config : Boolean;
2035    --  The setting of Prefix_Exception_Messages from configuration pragmas
2036 
2037    SPARK_Mode_Config : SPARK_Mode_Type := None;
2038    --  GNAT
2039    --  The setting of SPARK_Mode from configuration pragmas
2040 
2041    SPARK_Mode_Pragma_Config : Node_Id := Empty;
2042    --  If a SPARK_Mode pragma appeared in the configuration pragmas (setting
2043    --  SPARK_Mode_Config appropriately), then this points to the N_Pragma node.
2044 
2045    Uneval_Old_Config : Character;
2046    --  GNAT
2047    --  The setting of Uneval_Old from configuration pragmas
2048 
2049    Use_VADS_Size_Config : Boolean;
2050    --  GNAT
2051    --  This is the value of the configuration switch that controls the use of
2052    --  VADS_Size instead of Size wherever the attribute Size is used. It can
2053    --  be set True by the use of the pragma Use_VADS_Size in the gnat.adc file.
2054    --  This flag is used to set the initial value for Use_VADS_Size at the
2055    --  start of analyzing each unit. Note however that the setting of this flag
2056    --  is ignored for internal and predefined units (which are always compiled
2057    --  with the standard Size semantics).
2058 
2059    Warnings_As_Errors_Count_Config : Natural;
2060    --  GNAT
2061    --  Count of pattern strings stored from Warning_As_Error pragmas
2062 
2063    type Config_Switches_Type is private;
2064    --  Type used to save values of the switches set from Config values
2065 
2066    procedure Save_Opt_Config_Switches (Save : out Config_Switches_Type);
2067    --  This procedure saves the current values of the switches which are
2068    --  initialized from the above Config values, and then resets these switches
2069    --  according to the Config value settings.
2070 
2071    procedure Set_Opt_Config_Switches
2072      (Internal_Unit : Boolean;
2073       Main_Unit     : Boolean);
2074    --  This procedure sets the switches to the appropriate initial values. The
2075    --  parameter Internal_Unit is True for an internal or predefined unit, and
2076    --  affects the way the switches are set (see above). Main_Unit is true if
2077    --  switches are being set for the main unit or for the spec of the main
2078    --  unit. This affects setting of the assert/debug pragma switches, which
2079    --  are normally set false by default for an internal unit, except when the
2080    --  internal unit is the main unit, in which case we use the command line
2081    --  settings.
2082 
2083    procedure Restore_Opt_Config_Switches (Save : Config_Switches_Type);
2084    --  This procedure restores a set of switch values previously saved by a
2085    --  call to Save_Opt_Config_Switches (Save).
2086 
2087    procedure Register_Opt_Config_Switches;
2088    --  This procedure is called after processing the gnat.adc file and other
2089    --  configuration pragma files to record the values of the Config switches,
2090    --  as possibly modified by the use of command line switches and pragmas
2091    --  appearing in these files.
2092 
2093    ------------------------
2094    -- Other Global Flags --
2095    ------------------------
2096 
2097    Expander_Active : Boolean := False;
2098    --  A flag that indicates if expansion is active (True) or deactivated
2099    --  (False). When expansion is deactivated all calls to expander routines
2100    --  have no effect. Note that the initial setting of False is merely to
2101    --  prevent saving of an undefined value for an initial call to the
2102    --  Expander_Mode_Save_And_Set procedure. For more information on the use of
2103    --  this flag, see package Expander. Indeed this flag might more logically
2104    --  be in the spec of Expander, but it is referenced by Errout, and it
2105    --  really seems wrong for Errout to depend on Expander.
2106 
2107    Static_Dispatch_Tables : Boolean := True;
2108    --  This flag indicates if the backend supports generation of statically
2109    --  allocated dispatch tables. If it is True, then the front end will
2110    --  generate static aggregates for dispatch tables that contain forward
2111    --  references to addresses of subprograms not seen yet, and the back end
2112    --  must be prepared to handle this case. If it is False, then the front
2113    --  end generates assignments to initialize the dispatch table, and there
2114    --  are no such forward references. By default we build statically allocated
2115    --  dispatch tables for all library level tagged types in all platforms.This
2116    --  behavior can be disabled using switch -gnatd.t which will set this flag
2117    --  to False and revert to the previous dynamic behavior.
2118 
2119    -----------------------
2120    -- Tree I/O Routines --
2121    -----------------------
2122 
2123    procedure Tree_Read;
2124    --  Reads switch settings from current tree file using Tree_Read
2125 
2126    procedure Tree_Write;
2127    --  Writes out switch settings to current tree file using Tree_Write
2128 
2129    --------------------------
2130    -- ASIS Version Control --
2131    --------------------------
2132 
2133    --  These two variables (Tree_Version_String and Tree_ASIS_Version_Number)
2134    --  are supposed to be used in the GNAT/ASIS version check performed in
2135    --  the ASIS code (this package is also a part of the ASIS implementation).
2136    --  They are set by Tree_Read procedure, so they represent the version
2137    --  number (and the version string) of the compiler which has created the
2138    --  tree, and they are supposed to be compared with the corresponding values
2139    --  from the Tree_IO and Gnatvsn packages which also are a part of ASIS
2140    --  implementation.
2141 
2142    Tree_Version_String : String_Access;
2143    --  Used to store the compiler version string read from a tree file to check
2144    --  if it is from the same date as stored in the version string in Gnatvsn.
2145    --  We require that ASIS Pro can be used only with GNAT Pro, but we allow
2146    --  non-Pro ASIS and ASIS-based tools to be used with any version of the
2147    --  GNAT compiler. Therefore, we need the possibility to compare the dates
2148    --  of the corresponding source sets, using version strings that may be
2149    --  of different lengths.
2150 
2151    Tree_ASIS_Version_Number : Int;
2152    --  Used to store the ASIS version number read from a tree file to check if
2153    --  it is the same as stored in the ASIS version number in Tree_IO.
2154 
2155    -----------------------------------
2156    -- Modes for Formal Verification --
2157    -----------------------------------
2158 
2159    GNATprove_Mode : Boolean := False;
2160    --  Specific compiling mode targeting formal verification for those parts
2161    --  of the input code that belong to the SPARK 2014 subset of Ada. Set True
2162    --  by the gnat2why executable or by use of the -gnatd.F debug switch. Note
2163    --  that this is completely separate from the SPARK restriction defined in
2164    --  GNAT to detect violations of a subset of SPARK 2005 rules.
2165 
2166    ---------------------------
2167    -- Error/Warning Control --
2168    ---------------------------
2169 
2170    --  The following array would more reasonably be located in Err_Vars or
2171    --  Errour, but we put them here to deal with licensing issues (we need
2172    --  this to have the GPL exception licensing, since these variables and
2173    --  subprograms are accessed from units with this licensing).
2174 
2175    Warnings_As_Errors : array (1 .. 10_000) of String_Ptr;
2176    --  Table for recording Warning_As_Error pragmas as they are processed.
2177    --  It would be nicer to use Table, but there are circular elaboration
2178    --  problems if we try to do this, and an attempt to find some other
2179    --  appropriately licensed unit to declare this as a Table failed with
2180    --  various elaboration circularities. Memory is getting cheap these days!
2181 
2182    ---------------
2183    -- GNAT_Mode --
2184    ---------------
2185 
2186    GNAT_Mode : Boolean := False;
2187    --  GNAT
2188    --  True if compiling in GNAT system mode (-gnatg switch)
2189 
2190    GNAT_Mode_Config : Boolean := False;
2191    --  GNAT
2192    --  True if -gnatg switch is present. GNAT_Mode may be temporary set to
2193    --  True during the analysis of a system unit, but GNAT_Mode_Config must
2194    --  not change once scanned and set.
2195 
2196    --  Setting GNAT mode has the following effects on the language that is
2197    --  accepted. Note that several of the following have the effect of changing
2198    --  an error to a warning. But warnings are usually treated as fatal errors
2199    --  in -gnatg mode, so to actually take advantage of such a change, it is
2200    --  necessary to add an explicit pragma Warnings (Off) in the source and
2201    --  this requires clear documentation of why this is necessary.
2202 
2203    --    The identifier character set is set to 'n' (7-bit ASCII)
2204 
2205    --    Pragma Extend_System is ignored
2206 
2207    --    Warning_Mode is set to Treat_As_Error (-gnatwe)
2208 
2209    --    Standard style checks are set (See Set_GNAT_Style_Check_Options)
2210 
2211    --    Standard warnings are turned on (see Set_GNAT_Mode_Warnings)
2212 
2213    --    The Ada version is set to Ada 2012
2214 
2215    --    Task priorities are always allowed to be in the range Any_Priority
2216 
2217    --    Overflow checks are suppressed, overflow checking set to strict mode
2218 
2219    --    ALI files are always generated for predefined generic packages
2220 
2221    --    Obsolescent feature warnings are suppressed
2222 
2223    --    Recompilation of children of GNAT, System, Ada, Interfaces is allowed
2224 
2225    --    The Scalar_Storage_Order attribute applies to generic types
2226 
2227    --    Categorization errors are treated as warnings rather than errors
2228 
2229    --    Statements in preelaborated units give warnings rather than errors
2230 
2231    --    Private objects are allowed in preelaborated units
2232 
2233    --    Non-static constants in preelaborated units give warnings not errors
2234 
2235    --    The warning about component size being ignored is suppressed
2236 
2237    --    The warning about size clauses being ignored is suppressed
2238 
2239    --    Initializing limited types gives a warning rather than an error
2240 
2241    --    Copying of limited objects is allowed
2242 
2243    --    Returning objects of limited types is allowed
2244 
2245    --    Non-static call in preelaborated unit give a warning, not an error
2246 
2247    --    Warnings on possible elaboration errors are suppressed
2248 
2249    --    Warnings about packing being ignored are suppressed
2250 
2251    --    Warnings in internal units are not suppressed (they normally are)
2252 
2253    --    The only special comment sequence allowed is --!
2254 
2255    --------------------------
2256    -- Private Declarations --
2257    --------------------------
2258 
2259 private
2260 
2261    --  The following type is used to save and restore settings of switches in
2262    --  Opt that represent the configuration (i.e. result of config pragmas).
2263 
2264    --  Note that Ada_Version_Explicit is not included, since this is a sticky
2265    --  flag that once set does not get reset, since the whole idea of this flag
2266    --  is to record the setting for the main unit.
2267 
2268    type Config_Switches_Type is record
2269       Ada_Version                    : Ada_Version_Type;
2270       Ada_Version_Explicit           : Ada_Version_Type;
2271       Ada_Version_Pragma             : Node_Id;
2272       Assertions_Enabled             : Boolean;
2273       Assume_No_Invalid_Values       : Boolean;
2274       Check_Float_Overflow           : Boolean;
2275       Check_Policy_List              : Node_Id;
2276       Default_Pool                   : Node_Id;
2277       Default_SSO                    : Character;
2278       Dynamic_Elaboration_Checks     : Boolean;
2279       Exception_Locations_Suppressed : Boolean;
2280       Extensions_Allowed             : Boolean;
2281       External_Name_Exp_Casing       : External_Casing_Type;
2282       External_Name_Imp_Casing       : External_Casing_Type;
2283       Fast_Math                      : Boolean;
2284       Initialize_Scalars             : Boolean;
2285       Normalize_Scalars              : Boolean;
2286       Optimize_Alignment             : Character;
2287       Optimize_Alignment_Local       : Boolean;
2288       Persistent_BSS_Mode            : Boolean;
2289       Polling_Required               : Boolean;
2290       Prefix_Exception_Messages      : Boolean;
2291       SPARK_Mode                     : SPARK_Mode_Type;
2292       SPARK_Mode_Pragma              : Node_Id;
2293       Uneval_Old                     : Character;
2294       Use_VADS_Size                  : Boolean;
2295       Warnings_As_Errors_Count       : Natural;
2296    end record;
2297 
2298    --  The following declarations are for GCC version dependent flags. We do
2299    --  not let client code in the compiler test GCC_Version directly, but
2300    --  instead use deferred constants for relevant feature tags.
2301 
2302    --  Note: there currently are no such constants defined in this section,
2303    --  since the compiler front end is currently entirely independent of the
2304    --  GCC version, which is a desirable state of affairs.
2305 
2306    function get_gcc_version return Int;
2307    pragma Import (C, get_gcc_version, "get_gcc_version");
2308 
2309    GCC_Version : constant Nat := get_gcc_version;
2310    --  GNATMAKE
2311    --  Indicates which version of gcc is in use (3 = 3.x, 4 = 4.x). Note that
2312    --  gcc 2.8.1 (which used to be a value of 2) is no longer supported.
2313 
2314 end Opt;