File : types.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- T Y P E S --
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 host independent type definitions which are used
33 -- in more than one unit in the compiler. They are gathered here for easy
34 -- reference, although in some cases the full description is found in the
35 -- relevant module which implements the definition. The main reason that they
36 -- are not in their "natural" specs is that this would cause a lot of inter-
37 -- spec dependencies, and in particular some awkward circular dependencies
38 -- would have to be dealt with.
39
40 -- WARNING: There is a C version of this package. Any changes to this source
41 -- file must be properly reflected in the C header file types.h declarations.
42
43 -- Note: the declarations in this package reflect an expectation that the host
44 -- machine has an efficient integer base type with a range at least 32 bits
45 -- 2s-complement. If there are any machines for which this is not a correct
46 -- assumption, a significant number of changes will be required.
47
48 with System;
49 with Unchecked_Conversion;
50 with Unchecked_Deallocation;
51
52 package Types is
53 pragma Preelaborate;
54
55 -------------------------------
56 -- General Use Integer Types --
57 -------------------------------
58
59 type Int is range -2 ** 31 .. +2 ** 31 - 1;
60 -- Signed 32-bit integer
61
62 subtype Nat is Int range 0 .. Int'Last;
63 -- Non-negative Int values
64
65 subtype Pos is Int range 1 .. Int'Last;
66 -- Positive Int values
67
68 type Word is mod 2 ** 32;
69 -- Unsigned 32-bit integer
70
71 type Short is range -32768 .. +32767;
72 for Short'Size use 16;
73 -- 16-bit signed integer
74
75 type Byte is mod 2 ** 8;
76 for Byte'Size use 8;
77 -- 8-bit unsigned integer
78
79 type size_t is mod 2 ** Standard'Address_Size;
80 -- Memory size value, for use in calls to C routines
81
82 --------------------------------------
83 -- 8-Bit Character and String Types --
84 --------------------------------------
85
86 -- We use Standard.Character and Standard.String freely, since we are
87 -- compiling ourselves, and we properly implement the required 8-bit
88 -- character code as required in Ada 95. This section defines a few
89 -- general use constants and subtypes.
90
91 EOF : constant Character := ASCII.SUB;
92 -- The character SUB (16#1A#) is used in DOS and other systems derived
93 -- from DOS (XP, NT etc) to signal the end of a text file. Internally
94 -- all source files are ended by an EOF character, even on Unix systems.
95 -- An EOF character acts as the end of file only as the last character
96 -- of a source buffer, in any other position, it is treated as a blank
97 -- if it appears between tokens, and as an illegal character otherwise.
98 -- This makes life easier dealing with files that originated from DOS,
99 -- including concatenated files with interspersed EOF characters.
100
101 subtype Graphic_Character is Character range ' ' .. '~';
102 -- Graphic characters, as defined in ARM
103
104 subtype Line_Terminator is Character range ASCII.LF .. ASCII.CR;
105 -- Line terminator characters (LF, VT, FF, CR). For further details, see
106 -- the extensive discussion of line termination in the Sinput spec.
107
108 subtype Upper_Half_Character is
109 Character range Character'Val (16#80#) .. Character'Val (16#FF#);
110 -- 8-bit Characters with the upper bit set
111
112 type Character_Ptr is access all Character;
113 type String_Ptr is access all String;
114 type String_Ptr_Const is access constant String;
115 -- Standard character and string pointers
116
117 procedure Free is new Unchecked_Deallocation (String, String_Ptr);
118 -- Procedure for freeing dynamically allocated String values
119
120 subtype Big_String is String (Positive);
121 type Big_String_Ptr is access all Big_String;
122 -- Virtual type for handling imported big strings. Note that we should
123 -- never have any allocators for this type, but we don't give a storage
124 -- size of zero, since there are legitimate deallocations going on.
125
126 function To_Big_String_Ptr is
127 new Unchecked_Conversion (System.Address, Big_String_Ptr);
128 -- Used to obtain Big_String_Ptr values from external addresses
129
130 subtype Word_Hex_String is String (1 .. 8);
131 -- Type used to represent Word value as 8 hex digits, with lower case
132 -- letters for the alphabetic cases.
133
134 function Get_Hex_String (W : Word) return Word_Hex_String;
135 -- Convert word value to 8-character hex string
136
137 -----------------------------------------
138 -- Types Used for Text Buffer Handling --
139 -----------------------------------------
140
141 -- We can not use type String for text buffers, since we must use the
142 -- standard 32-bit integer as an index value, since we count on all index
143 -- values being the same size.
144
145 type Text_Ptr is new Int;
146 -- Type used for subscripts in text buffer
147
148 type Text_Buffer is array (Text_Ptr range <>) of Character;
149 -- Text buffer used to hold source file or library information file
150
151 type Text_Buffer_Ptr is access all Text_Buffer;
152 -- Text buffers for input files are allocated dynamically and this type
153 -- is used to reference these text buffers.
154
155 procedure Free is new Unchecked_Deallocation (Text_Buffer, Text_Buffer_Ptr);
156 -- Procedure for freeing dynamically allocated text buffers
157
158 ------------------------------------------
159 -- Types Used for Source Input Handling --
160 ------------------------------------------
161
162 type Logical_Line_Number is range 0 .. Int'Last;
163 for Logical_Line_Number'Size use 32;
164 -- Line number type, used for storing logical line numbers (i.e. line
165 -- numbers that include effects of any Source_Reference pragmas in the
166 -- source file). The value zero indicates a line containing a source
167 -- reference pragma.
168
169 No_Line_Number : constant Logical_Line_Number := 0;
170 -- Special value used to indicate no line number
171
172 type Physical_Line_Number is range 1 .. Int'Last;
173 for Physical_Line_Number'Size use 32;
174 -- Line number type, used for storing physical line numbers (i.e. line
175 -- numbers in the physical file being compiled, unaffected by the presence
176 -- of source reference pragmas).
177
178 type Column_Number is range 0 .. 32767;
179 for Column_Number'Size use 16;
180 -- Column number (assume that 2**15 - 1 is large enough). The range for
181 -- this type is used to compute Hostparm.Max_Line_Length. See also the
182 -- processing for -gnatyM in Stylesw).
183
184 No_Column_Number : constant Column_Number := 0;
185 -- Special value used to indicate no column number
186
187 Source_Align : constant := 2 ** 12;
188 -- Alignment requirement for source buffers (by keeping source buffers
189 -- aligned, we can optimize the implementation of Get_Source_File_Index.
190 -- See this routine in Sinput for details.
191
192 subtype Source_Buffer is Text_Buffer;
193 -- Type used to store text of a source file. The buffer for the main
194 -- source (the source specified on the command line) has a lower bound
195 -- starting at zero. Subsequent subsidiary sources have lower bounds
196 -- which are one greater than the previous upper bound, rounded up to
197 -- a multiple of Source_Align.
198
199 subtype Big_Source_Buffer is Text_Buffer (0 .. Text_Ptr'Last);
200 -- This is a virtual type used as the designated type of the access type
201 -- Source_Buffer_Ptr, see Osint.Read_Source_File for details.
202
203 type Source_Buffer_Ptr is access all Big_Source_Buffer;
204 -- Pointer to source buffer. We use virtual origin addressing for source
205 -- buffers, with thin pointers. The pointer points to a virtual instance
206 -- of type Big_Source_Buffer, where the actual type is in fact of type
207 -- Source_Buffer. The address is adjusted so that the virtual origin
208 -- addressing works correctly. See Osint.Read_Source_Buffer for further
209 -- details. Again, as for Big_String_Ptr, we should never allocate using
210 -- this type, but we don't give a storage size clause of zero, since we
211 -- may end up doing deallocations of instances allocated manually.
212
213 subtype Source_Ptr is Text_Ptr;
214 -- Type used to represent a source location, which is a subscript of a
215 -- character in the source buffer. As noted above, different source buffers
216 -- have different ranges, so it is possible to tell from a Source_Ptr value
217 -- which source it refers to. Note that negative numbers are allowed to
218 -- accommodate the following special values.
219
220 No_Location : constant Source_Ptr := -1;
221 -- Value used to indicate no source position set in a node. A test for a
222 -- Source_Ptr value being > No_Location is the approved way to test for a
223 -- standard value that does not include No_Location or any of the following
224 -- special definitions. One important use of No_Location is to label
225 -- generated nodes that we don't want the debugger to see in normal mode
226 -- (very often we conditionalize so that we set No_Location in normal mode
227 -- and the corresponding source line in -gnatD mode).
228
229 Standard_Location : constant Source_Ptr := -2;
230 -- Used for all nodes in the representation of package Standard other than
231 -- nodes representing the contents of Standard.ASCII. Note that testing for
232 -- a value being <= Standard_Location tests for both Standard_Location and
233 -- for Standard_ASCII_Location.
234
235 Standard_ASCII_Location : constant Source_Ptr := -3;
236 -- Used for all nodes in the presentation of package Standard.ASCII
237
238 System_Location : constant Source_Ptr := -4;
239 -- Used to identify locations of pragmas scanned by Targparm, where we know
240 -- the location is in System, but we don't know exactly what line.
241
242 First_Source_Ptr : constant Source_Ptr := 0;
243 -- Starting source pointer index value for first source program
244
245 -------------------------------------
246 -- Range Definitions for Tree Data --
247 -------------------------------------
248
249 -- The tree has fields that can hold any of the following types:
250
251 -- Pointers to other tree nodes (type Node_Id)
252 -- List pointers (type List_Id)
253 -- Element list pointers (type Elist_Id)
254 -- Names (type Name_Id)
255 -- Strings (type String_Id)
256 -- Universal integers (type Uint)
257 -- Universal reals (type Ureal)
258
259 -- In most contexts, the strongly typed interface determines which of these
260 -- types is present. However, there are some situations (involving untyped
261 -- traversals of the tree), where it is convenient to be easily able to
262 -- distinguish these values. The underlying representation in all cases is
263 -- an integer type Union_Id, and we ensure that the range of the various
264 -- possible values for each of the above types is disjoint so that this
265 -- distinction is possible.
266
267 -- Note: it is also helpful for debugging purposes to make these ranges
268 -- distinct. If a bug leads to misidentification of a value, then it will
269 -- typically result in an out of range value and a Constraint_Error.
270
271 type Union_Id is new Int;
272 -- The type in the tree for a union of possible ID values
273
274 List_Low_Bound : constant := -100_000_000;
275 -- The List_Id values are subscripts into an array of list headers which
276 -- has List_Low_Bound as its lower bound. This value is chosen so that all
277 -- List_Id values are negative, and the value zero is in the range of both
278 -- List_Id and Node_Id values (see further description below).
279
280 List_High_Bound : constant := 0;
281 -- Maximum List_Id subscript value. This allows up to 100 million list Id
282 -- values, which is in practice infinite, and there is no need to check the
283 -- range. The range overlaps the node range by one element (with value
284 -- zero), which is used both for the Empty node, and for indicating no
285 -- list. The fact that the same value is used is convenient because it
286 -- means that the default value of Empty applies to both nodes and lists,
287 -- and also is more efficient to test for.
288
289 Node_Low_Bound : constant := 0;
290 -- The tree Id values start at zero, because we use zero for Empty (to
291 -- allow a zero test for Empty). Actual tree node subscripts start at 0
292 -- since Empty is a legitimate node value.
293
294 Node_High_Bound : constant := 099_999_999;
295 -- Maximum number of nodes that can be allocated is 100 million, which
296 -- is in practice infinite, and there is no need to check the range.
297
298 Elist_Low_Bound : constant := 100_000_000;
299 -- The Elist_Id values are subscripts into an array of elist headers which
300 -- has Elist_Low_Bound as its lower bound.
301
302 Elist_High_Bound : constant := 199_999_999;
303 -- Maximum Elist_Id subscript value. This allows up to 100 million Elists,
304 -- which is in practice infinite and there is no need to check the range.
305
306 Elmt_Low_Bound : constant := 200_000_000;
307 -- Low bound of element Id values. The use of these values is internal to
308 -- the Elists package, but the definition of the range is included here
309 -- since it must be disjoint from other Id values. The Elmt_Id values are
310 -- subscripts into an array of list elements which has this as lower bound.
311
312 Elmt_High_Bound : constant := 299_999_999;
313 -- Upper bound of Elmt_Id values. This allows up to 100 million element
314 -- list members, which is in practice infinite (no range check needed).
315
316 Names_Low_Bound : constant := 300_000_000;
317 -- Low bound for name Id values
318
319 Names_High_Bound : constant := 399_999_999;
320 -- Maximum number of names that can be allocated is 100 million, which is
321 -- in practice infinite and there is no need to check the range.
322
323 Strings_Low_Bound : constant := 400_000_000;
324 -- Low bound for string Id values
325
326 Strings_High_Bound : constant := 499_999_999;
327 -- Maximum number of strings that can be allocated is 100 million, which
328 -- is in practice infinite and there is no need to check the range.
329
330 Ureal_Low_Bound : constant := 500_000_000;
331 -- Low bound for Ureal values
332
333 Ureal_High_Bound : constant := 599_999_999;
334 -- Maximum number of Ureal values stored is 100_000_000 which is in
335 -- practice infinite so that no check is required.
336
337 Uint_Low_Bound : constant := 600_000_000;
338 -- Low bound for Uint values
339
340 Uint_Table_Start : constant := 2_000_000_000;
341 -- Location where table entries for universal integers start (see
342 -- Uintp spec for details of the representation of Uint values).
343
344 Uint_High_Bound : constant := 2_099_999_999;
345 -- The range of Uint values is very large, since a substantial part
346 -- of this range is used to store direct values, see Uintp for details.
347
348 -- The following subtype definitions are used to provide convenient names
349 -- for membership tests on Int values to see what data type range they
350 -- lie in. Such tests appear only in the lowest level packages.
351
352 subtype List_Range is Union_Id
353 range List_Low_Bound .. List_High_Bound;
354
355 subtype Node_Range is Union_Id
356 range Node_Low_Bound .. Node_High_Bound;
357
358 subtype Elist_Range is Union_Id
359 range Elist_Low_Bound .. Elist_High_Bound;
360
361 subtype Elmt_Range is Union_Id
362 range Elmt_Low_Bound .. Elmt_High_Bound;
363
364 subtype Names_Range is Union_Id
365 range Names_Low_Bound .. Names_High_Bound;
366
367 subtype Strings_Range is Union_Id
368 range Strings_Low_Bound .. Strings_High_Bound;
369
370 subtype Uint_Range is Union_Id
371 range Uint_Low_Bound .. Uint_High_Bound;
372
373 subtype Ureal_Range is Union_Id
374 range Ureal_Low_Bound .. Ureal_High_Bound;
375
376 -----------------------------
377 -- Types for Atree Package --
378 -----------------------------
379
380 -- Node_Id values are used to identify nodes in the tree. They are
381 -- subscripts into the Nodes table declared in package Atree. Note that
382 -- the special values Empty and Error are subscripts into this table.
383 -- See package Atree for further details.
384
385 type Node_Id is range Node_Low_Bound .. Node_High_Bound;
386 -- Type used to identify nodes in the tree
387
388 subtype Entity_Id is Node_Id;
389 -- A synonym for node types, used in the Einfo package to refer to nodes
390 -- that are entities (i.e. nodes with an Nkind of N_Defining_xxx). All such
391 -- nodes are extended nodes and these are the only extended nodes, so that
392 -- in practice entity and extended nodes are synonymous.
393
394 subtype Node_Or_Entity_Id is Node_Id;
395 -- A synonym for node types, used in cases where a given value may be used
396 -- to represent either a node or an entity. We like to minimize such uses
397 -- for obvious reasons of logical type consistency, but where such uses
398 -- occur, they should be documented by use of this type.
399
400 Empty : constant Node_Id := Node_Low_Bound;
401 -- Used to indicate null node. A node is actually allocated with this
402 -- Id value, so that Nkind (Empty) = N_Empty. Note that Node_Low_Bound
403 -- is zero, so Empty = No_List = zero.
404
405 Empty_List_Or_Node : constant := 0;
406 -- This constant is used in situations (e.g. initializing empty fields)
407 -- where the value set will be used to represent either an empty node or
408 -- a non-existent list, depending on the context.
409
410 Error : constant Node_Id := Node_Low_Bound + 1;
411 -- Used to indicate an error in the source program. A node is actually
412 -- allocated with this Id value, so that Nkind (Error) = N_Error.
413
414 Empty_Or_Error : constant Node_Id := Error;
415 -- Since Empty and Error are the first two Node_Id values, the test for
416 -- N <= Empty_Or_Error tests to see if N is Empty or Error. This definition
417 -- provides convenient self-documentation for such tests.
418
419 First_Node_Id : constant Node_Id := Node_Low_Bound;
420 -- Subscript of first allocated node. Note that Empty and Error are both
421 -- allocated nodes, whose Nkind fields can be accessed without error.
422
423 ------------------------------
424 -- Types for Nlists Package --
425 ------------------------------
426
427 -- List_Id values are used to identify node lists stored in the tree, so
428 -- that each node can be on at most one such list (see package Nlists for
429 -- further details). Note that the special value Error_List is a subscript
430 -- in this table, but the value No_List is *not* a valid subscript, and any
431 -- attempt to apply list operations to No_List will cause a (detected)
432 -- error.
433
434 type List_Id is range List_Low_Bound .. List_High_Bound;
435 -- Type used to identify a node list
436
437 No_List : constant List_Id := List_High_Bound;
438 -- Used to indicate absence of a list. Note that the value is zero, which
439 -- is the same as Empty, which is helpful in initializing nodes where a
440 -- value of zero can represent either an empty node or an empty list.
441
442 Error_List : constant List_Id := List_Low_Bound;
443 -- Used to indicate that there was an error in the source program in a
444 -- context which would normally require a list. This node appears to be
445 -- an empty list to the list operations (a null list is actually allocated
446 -- which has this Id value).
447
448 First_List_Id : constant List_Id := Error_List;
449 -- Subscript of first allocated list header
450
451 ------------------------------
452 -- Types for Elists Package --
453 ------------------------------
454
455 -- Element list Id values are used to identify element lists stored outside
456 -- of the tree, allowing nodes to be members of more than one such list
457 -- (see package Elists for further details).
458
459 type Elist_Id is range Elist_Low_Bound .. Elist_High_Bound;
460 -- Type used to identify an element list (Elist header table subscript)
461
462 No_Elist : constant Elist_Id := Elist_Low_Bound;
463 -- Used to indicate absence of an element list. Note that this is not an
464 -- actual Elist header, so element list operations on this value are not
465 -- valid.
466
467 First_Elist_Id : constant Elist_Id := No_Elist + 1;
468 -- Subscript of first allocated Elist header
469
470 -- Element Id values are used to identify individual elements of an element
471 -- list (see package Elists for further details).
472
473 type Elmt_Id is range Elmt_Low_Bound .. Elmt_High_Bound;
474 -- Type used to identify an element list
475
476 No_Elmt : constant Elmt_Id := Elmt_Low_Bound;
477 -- Used to represent empty element
478
479 First_Elmt_Id : constant Elmt_Id := No_Elmt + 1;
480 -- Subscript of first allocated Elmt table entry
481
482 -------------------------------
483 -- Types for Stringt Package --
484 -------------------------------
485
486 -- String_Id values are used to identify entries in the strings table. They
487 -- are subscripts into the Strings table defined in package Stringt.
488
489 -- Note that with only a few exceptions, which are clearly documented, the
490 -- type String_Id should be regarded as a private type. In particular it is
491 -- never appropriate to perform arithmetic operations using this type.
492 -- Doesn't this also apply to all other *_Id types???
493
494 type String_Id is range Strings_Low_Bound .. Strings_High_Bound;
495 -- Type used to identify entries in the strings table
496
497 No_String : constant String_Id := Strings_Low_Bound;
498 -- Used to indicate missing string Id. Note that the value zero is used
499 -- to indicate a missing data value for all the Int types in this section.
500
501 First_String_Id : constant String_Id := No_String + 1;
502 -- First subscript allocated in string table
503
504 -------------------------
505 -- Character Code Type --
506 -------------------------
507
508 -- The type Char is used for character data internally in the compiler, but
509 -- character codes in the source are represented by the Char_Code type.
510 -- Each character literal in the source is interpreted as being one of the
511 -- 16#7FFF_FFFF# possible Wide_Wide_Character codes, and a unique Integer
512 -- value is assigned, corresponding to the UTF-32 value, which also
513 -- corresponds to the Pos value in the Wide_Wide_Character type, and also
514 -- corresponds to the Pos value in the Wide_Character and Character types
515 -- for values that are in appropriate range. String literals are similarly
516 -- interpreted as a sequence of such codes.
517
518 type Char_Code_Base is mod 2 ** 32;
519 for Char_Code_Base'Size use 32;
520
521 subtype Char_Code is Char_Code_Base range 0 .. 16#7FFF_FFFF#;
522 for Char_Code'Value_Size use 32;
523 for Char_Code'Object_Size use 32;
524
525 function Get_Char_Code (C : Character) return Char_Code;
526 pragma Inline (Get_Char_Code);
527 -- Function to obtain internal character code from source character. For
528 -- the moment, the internal character code is simply the Pos value of the
529 -- input source character, but we provide this interface for possible
530 -- later support of alternative character sets.
531
532 function In_Character_Range (C : Char_Code) return Boolean;
533 pragma Inline (In_Character_Range);
534 -- Determines if the given character code is in range of type Character,
535 -- and if so, returns True. If not, returns False.
536
537 function In_Wide_Character_Range (C : Char_Code) return Boolean;
538 pragma Inline (In_Wide_Character_Range);
539 -- Determines if the given character code is in range of the type
540 -- Wide_Character, and if so, returns True. If not, returns False.
541
542 function Get_Character (C : Char_Code) return Character;
543 pragma Inline (Get_Character);
544 -- For a character C that is in Character range (see above function), this
545 -- function returns the corresponding Character value. It is an error to
546 -- call Get_Character if C is not in Character range.
547
548 function Get_Wide_Character (C : Char_Code) return Wide_Character;
549 -- For a character C that is in Wide_Character range (see above function),
550 -- this function returns the corresponding Wide_Character value. It is an
551 -- error to call Get_Wide_Character if C is not in Wide_Character range.
552
553 ---------------------------------------
554 -- Types used for Library Management --
555 ---------------------------------------
556
557 type Unit_Number_Type is new Int range -1 .. Int'Last;
558 -- Unit number. The main source is unit 0, and subsidiary sources have
559 -- non-zero numbers starting with 1. Unit numbers are used to index the
560 -- Units table in package Lib.
561
562 Main_Unit : constant Unit_Number_Type := 0;
563 -- Unit number value for main unit
564
565 No_Unit : constant Unit_Number_Type := -1;
566 -- Special value used to signal no unit
567
568 type Source_File_Index is new Int range -1 .. Int'Last;
569 -- Type used to index the source file table (see package Sinput)
570
571 Internal_Source_File : constant Source_File_Index :=
572 Source_File_Index'First;
573 -- Value used to indicate the buffer for the source-code-like strings
574 -- internally created withing the compiler (see package Sinput)
575
576 No_Source_File : constant Source_File_Index := 0;
577 -- Value used to indicate no source file present
578
579 -----------------------------------
580 -- Representation of Time Stamps --
581 -----------------------------------
582
583 -- All compiled units are marked with a time stamp which is derived from
584 -- the source file (we assume that the host system has the concept of a
585 -- file time stamp which is modified when a file is modified). These
586 -- time stamps are used to ensure consistency of the set of units that
587 -- constitutes a library. Time stamps are 14-character strings with
588 -- with the following format:
589
590 -- YYYYMMDDHHMMSS
591
592 -- YYYY year
593 -- MM month (2 digits 01-12)
594 -- DD day (2 digits 01-31)
595 -- HH hour (2 digits 00-23)
596 -- MM minutes (2 digits 00-59)
597 -- SS seconds (2 digits 00-59)
598
599 -- In the case of Unix systems (and other systems which keep the time in
600 -- GMT), the time stamp is the GMT time of the file, not the local time.
601 -- This solves problems in using libraries across networks with clients
602 -- spread across multiple time-zones.
603
604 Time_Stamp_Length : constant := 14;
605 -- Length of time stamp value
606
607 subtype Time_Stamp_Index is Natural range 1 .. Time_Stamp_Length;
608 type Time_Stamp_Type is new String (Time_Stamp_Index);
609 -- Type used to represent time stamp
610
611 Empty_Time_Stamp : constant Time_Stamp_Type := (others => ' ');
612 -- Value representing an empty or missing time stamp. Looks less than any
613 -- real time stamp if two time stamps are compared. Note that although this
614 -- is not private, clients should not rely on the exact way in which this
615 -- string is represented, and instead should use the subprograms below.
616
617 Dummy_Time_Stamp : constant Time_Stamp_Type := (others => '0');
618 -- This is used for dummy time stamp values used in the D lines for
619 -- non-existent files, and is intended to be an impossible value.
620
621 function "=" (Left, Right : Time_Stamp_Type) return Boolean;
622 function "<=" (Left, Right : Time_Stamp_Type) return Boolean;
623 function ">=" (Left, Right : Time_Stamp_Type) return Boolean;
624 function "<" (Left, Right : Time_Stamp_Type) return Boolean;
625 function ">" (Left, Right : Time_Stamp_Type) return Boolean;
626 -- Comparison functions on time stamps. Note that two time stamps are
627 -- defined as being equal if they have the same day/month/year and the
628 -- hour/minutes/seconds values are within 2 seconds of one another. This
629 -- deals with rounding effects in library file time stamps caused by
630 -- copying operations during installation. We have particularly noticed
631 -- that WinNT seems susceptible to such changes.
632 --
633 -- Note: the Empty_Time_Stamp value looks equal to itself, and less than
634 -- any non-empty time stamp value.
635
636 procedure Split_Time_Stamp
637 (TS : Time_Stamp_Type;
638 Year : out Nat;
639 Month : out Nat;
640 Day : out Nat;
641 Hour : out Nat;
642 Minutes : out Nat;
643 Seconds : out Nat);
644 -- Given a time stamp, decompose it into its components
645
646 procedure Make_Time_Stamp
647 (Year : Nat;
648 Month : Nat;
649 Day : Nat;
650 Hour : Nat;
651 Minutes : Nat;
652 Seconds : Nat;
653 TS : out Time_Stamp_Type);
654 -- Given the components of a time stamp, initialize the value
655
656 -------------------------------------
657 -- Types used for Check Management --
658 -------------------------------------
659
660 type Check_Id is new Nat;
661 -- Type used to represent a check id
662
663 No_Check_Id : constant := 0;
664 -- Check_Id value used to indicate no check
665
666 Access_Check : constant := 1;
667 Accessibility_Check : constant := 2;
668 Alignment_Check : constant := 3;
669 Allocation_Check : constant := 4;
670 Atomic_Synchronization : constant := 5;
671 Discriminant_Check : constant := 6;
672 Division_Check : constant := 7;
673 Duplicated_Tag_Check : constant := 8;
674 Elaboration_Check : constant := 9;
675 Index_Check : constant := 10;
676 Length_Check : constant := 11;
677 Overflow_Check : constant := 12;
678 Predicate_Check : constant := 13;
679 Range_Check : constant := 14;
680 Storage_Check : constant := 15;
681 Tag_Check : constant := 16;
682 Validity_Check : constant := 17;
683 Container_Checks : constant := 18;
684 Tampering_Check : constant := 19;
685 -- Values used to represent individual predefined checks (including the
686 -- setting of Atomic_Synchronization, which is implemented internally using
687 -- a "check" whose name is Atomic_Synchronization).
688
689 All_Checks : constant := 20;
690 -- Value used to represent All_Checks value
691
692 subtype Predefined_Check_Id is Check_Id range 1 .. All_Checks;
693 -- Subtype for predefined checks, including All_Checks
694
695 -- The following array contains an entry for each recognized check name
696 -- for pragma Suppress. It is used to represent current settings of scope
697 -- based suppress actions from pragma Suppress or command line settings.
698
699 -- Note: when Suppress_Array (All_Checks) is True, then generally all other
700 -- specific check entries are set True, except for the Elaboration_Check
701 -- entry which is set only if an explicit Suppress for this check is given.
702 -- The reason for this non-uniformity is that we do not want All_Checks to
703 -- suppress elaboration checking when using the static elaboration model.
704 -- We recognize only an explicit suppress of Elaboration_Check as a signal
705 -- that the static elaboration checking should skip a compile time check.
706
707 type Suppress_Array is array (Predefined_Check_Id) of Boolean;
708 pragma Pack (Suppress_Array);
709
710 -- To add a new check type to GNAT, the following steps are required:
711
712 -- 1. Add an entry to Snames spec for the new name
713 -- 2. Add an entry to the definition of Check_Id above
714 -- 3. Add a new function to Checks to handle the new check test
715 -- 4. Add a new Do_xxx_Check flag to Sinfo (if required)
716 -- 5. Add appropriate checks for the new test
717
718 -- The following provides precise details on the mode used to generate
719 -- code for intermediate operations in expressions for signed integer
720 -- arithmetic (and how to generate overflow checks if enabled). Note
721 -- that this only affects handling of intermediate results. The final
722 -- result must always fit within the target range, and if overflow
723 -- checking is enabled, the check on the final result is against this
724 -- target range.
725
726 type Overflow_Mode_Type is (
727 Not_Set,
728 -- Dummy value used during initialization process to show that the
729 -- corresponding value has not yet been initialized.
730
731 Strict,
732 -- Operations are done in the base type of the subexpression. If
733 -- overflow checks are enabled, then the check is against the range
734 -- of this base type.
735
736 Minimized,
737 -- Where appropriate, intermediate arithmetic operations are performed
738 -- with an extended range, using Long_Long_Integer if necessary. If
739 -- overflow checking is enabled, then the check is against the range
740 -- of Long_Long_Integer.
741
742 Eliminated);
743 -- In this mode arbitrary precision arithmetic is used as needed to
744 -- ensure that it is impossible for intermediate arithmetic to cause an
745 -- overflow. In this mode, intermediate expressions are not affected by
746 -- the overflow checking mode, since overflows are eliminated.
747
748 subtype Minimized_Or_Eliminated is
749 Overflow_Mode_Type range Minimized .. Eliminated;
750 -- Define subtype so that clients don't need to know ordering. Note that
751 -- Overflow_Mode_Type is not marked as an ordered enumeration type.
752
753 -- The following structure captures the state of check suppression or
754 -- activation at a particular point in the program execution.
755
756 type Suppress_Record is record
757 Suppress : Suppress_Array;
758 -- Indicates suppression status of each possible check
759
760 Overflow_Mode_General : Overflow_Mode_Type;
761 -- This field indicates the mode for handling code generation and
762 -- overflow checking (if enabled) for intermediate expression values.
763 -- This applies to general expressions outside assertions.
764
765 Overflow_Mode_Assertions : Overflow_Mode_Type;
766 -- This field indicates the mode for handling code generation and
767 -- overflow checking (if enabled) for intermediate expression values.
768 -- This applies to any expression occuring inside assertions.
769 end record;
770
771 -----------------------------------
772 -- Global Exception Declarations --
773 -----------------------------------
774
775 -- This section contains declarations of exceptions that are used
776 -- throughout the compiler or in other GNAT tools.
777
778 Unrecoverable_Error : exception;
779 -- This exception is raised to immediately terminate the compilation of the
780 -- current source program. Used in situations where things are bad enough
781 -- that it doesn't seem worth continuing (e.g. max errors reached, or a
782 -- required file is not found). Also raised when the compiler finds itself
783 -- in trouble after an error (see Comperr).
784
785 Terminate_Program : exception;
786 -- This exception is raised to immediately terminate the tool being
787 -- executed. Each tool where this exception may be raised must have a
788 -- single exception handler that contains only a null statement and that is
789 -- the last statement of the program. If needed, procedure Set_Exit_Status
790 -- is called with the appropriate exit status before raising
791 -- Terminate_Program.
792
793 ---------------------------------
794 -- Parameter Mechanism Control --
795 ---------------------------------
796
797 -- Function and parameter entities have a field that records the passing
798 -- mechanism. See specification of Sem_Mech for full details. The following
799 -- subtype is used to represent values of this type:
800
801 subtype Mechanism_Type is Int range -2 .. Int'Last;
802 -- Type used to represent a mechanism value. This is a subtype rather than
803 -- a type to avoid some annoying processing problems with certain routines
804 -- in Einfo (processing them to create the corresponding C). The values in
805 -- the range -2 .. 0 are used to represent mechanism types declared as
806 -- named constants in the spec of Sem_Mech. Positive values are used for
807 -- the case of a pragma C_Pass_By_Copy that sets a threshold value for the
808 -- mechanism to be used. For example if pragma C_Pass_By_Copy (32) is given
809 -- then Default_C_Record_Mechanism is set to 32, and the meaning is to use
810 -- By_Reference if the size is greater than 32, and By_Copy otherwise.
811
812 ------------------------------
813 -- Run-Time Exception Codes --
814 ------------------------------
815
816 -- When the code generator generates a run-time exception, it provides a
817 -- reason code which is one of the following. This reason code is used to
818 -- select the appropriate run-time routine to be called, determining both
819 -- the exception to be raised, and the message text to be added.
820
821 -- The prefix CE/PE/SE indicates the exception to be raised
822 -- CE = Constraint_Error
823 -- PE = Program_Error
824 -- SE = Storage_Error
825
826 -- The remaining part of the name indicates the message text to be added,
827 -- where all letters are lower case, and underscores are converted to
828 -- spaces (for example CE_Invalid_Data adds the text "invalid data").
829
830 -- To add a new code, you need to do the following:
831
832 -- 1. Assign a new number to the reason. Do not renumber existing codes,
833 -- since this causes compatibility/bootstrap issues, so always add the
834 -- new code at the end of the list.
835
836 -- 2. Update the contents of the array Kind
837
838 -- 3. Modify the corresponding definitions in types.h, including the
839 -- definition of last_reason_code.
840
841 -- 4. Add the name of the routines in exp_ch11.Get_RT_Exception_Name
842
843 -- 5. Add a new routine in Ada.Exceptions with the appropriate call and
844 -- static string constant. Note that there is more than one version
845 -- of a-except.adb which must be modified.
846
847 -- Note on ordering of references. For the tables in Ada.Exceptions units,
848 -- usually the ordering does not matter, and we use the same ordering as
849 -- is used here (note the requirement in the ordering here that CE/PE/SE
850 -- codes be kept together, so the subtype declarations work OK).
851
852 type RT_Exception_Code is
853 (CE_Access_Check_Failed, -- 00
854 CE_Access_Parameter_Is_Null, -- 01
855 CE_Discriminant_Check_Failed, -- 02
856 CE_Divide_By_Zero, -- 03
857 CE_Explicit_Raise, -- 04
858 CE_Index_Check_Failed, -- 05
859 CE_Invalid_Data, -- 06
860 CE_Length_Check_Failed, -- 07
861 CE_Null_Exception_Id, -- 08
862 CE_Null_Not_Allowed, -- 09
863
864 CE_Overflow_Check_Failed, -- 10
865 CE_Partition_Check_Failed, -- 11
866 CE_Range_Check_Failed, -- 12
867 CE_Tag_Check_Failed, -- 13
868 PE_Access_Before_Elaboration, -- 14
869 PE_Accessibility_Check_Failed, -- 15
870 PE_Address_Of_Intrinsic, -- 16
871 PE_Aliased_Parameters, -- 17
872 PE_All_Guards_Closed, -- 18
873 PE_Bad_Predicated_Generic_Type, -- 19
874
875 PE_Current_Task_In_Entry_Body, -- 20
876 PE_Duplicated_Entry_Address, -- 21
877 PE_Explicit_Raise, -- 22
878 PE_Finalize_Raised_Exception, -- 23
879 PE_Implicit_Return, -- 24
880 PE_Misaligned_Address_Value, -- 25
881 PE_Missing_Return, -- 26
882 PE_Overlaid_Controlled_Object, -- 27
883 PE_Potentially_Blocking_Operation, -- 28
884 PE_Stubbed_Subprogram_Called, -- 29
885
886 PE_Unchecked_Union_Restriction, -- 30
887 PE_Non_Transportable_Actual, -- 31
888 SE_Empty_Storage_Pool, -- 32
889 SE_Explicit_Raise, -- 33
890 SE_Infinite_Recursion, -- 34
891 SE_Object_Too_Large, -- 35
892 PE_Stream_Operation_Not_Allowed); -- 36
893
894 Last_Reason_Code : constant := 36;
895 -- Last reason code
896
897 type Reason_Kind is (CE_Reason, PE_Reason, SE_Reason);
898 -- Categorization of reason codes by exception raised
899
900 Rkind : constant array (RT_Exception_Code range <>) of Reason_Kind :=
901 (CE_Access_Check_Failed => CE_Reason,
902 CE_Access_Parameter_Is_Null => CE_Reason,
903 CE_Discriminant_Check_Failed => CE_Reason,
904 CE_Divide_By_Zero => CE_Reason,
905 CE_Explicit_Raise => CE_Reason,
906 CE_Index_Check_Failed => CE_Reason,
907 CE_Invalid_Data => CE_Reason,
908 CE_Length_Check_Failed => CE_Reason,
909 CE_Null_Exception_Id => CE_Reason,
910 CE_Null_Not_Allowed => CE_Reason,
911 CE_Overflow_Check_Failed => CE_Reason,
912 CE_Partition_Check_Failed => CE_Reason,
913 CE_Range_Check_Failed => CE_Reason,
914 CE_Tag_Check_Failed => CE_Reason,
915
916 PE_Access_Before_Elaboration => PE_Reason,
917 PE_Accessibility_Check_Failed => PE_Reason,
918 PE_Address_Of_Intrinsic => PE_Reason,
919 PE_Aliased_Parameters => PE_Reason,
920 PE_All_Guards_Closed => PE_Reason,
921 PE_Bad_Predicated_Generic_Type => PE_Reason,
922 PE_Current_Task_In_Entry_Body => PE_Reason,
923 PE_Duplicated_Entry_Address => PE_Reason,
924 PE_Explicit_Raise => PE_Reason,
925 PE_Finalize_Raised_Exception => PE_Reason,
926 PE_Implicit_Return => PE_Reason,
927 PE_Misaligned_Address_Value => PE_Reason,
928 PE_Missing_Return => PE_Reason,
929 PE_Overlaid_Controlled_Object => PE_Reason,
930 PE_Potentially_Blocking_Operation => PE_Reason,
931 PE_Stubbed_Subprogram_Called => PE_Reason,
932 PE_Unchecked_Union_Restriction => PE_Reason,
933 PE_Non_Transportable_Actual => PE_Reason,
934 PE_Stream_Operation_Not_Allowed => PE_Reason,
935
936 SE_Empty_Storage_Pool => SE_Reason,
937 SE_Explicit_Raise => SE_Reason,
938 SE_Infinite_Recursion => SE_Reason,
939 SE_Object_Too_Large => SE_Reason);
940
941 end Types;