summaryrefslogtreecommitdiff
path: root/gcc/ada/a-exexda.adb
blob: 63ab461a9faa65cbeeaf4d8d888f8bc91a01146b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                       ADA.EXCEPTIONS.EXCEPTION_DATA                      --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2010, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with System.Storage_Elements; use System.Storage_Elements;

separate (Ada.Exceptions)
package body Exception_Data is

   --  This unit implements the Exception_Information related services for
   --  both the Ada standard requirements and the GNAT.Exception_Traces
   --  facility.

   --  There are common parts between the contents of Exception_Information
   --  (the regular Ada interface) and Tailored_Exception_Information (what
   --  the automatic backtracing output includes). The overall structure is
   --  sketched below:

   --
   --                      Exception_Information
   --                               |
   --                       +-------+--------+
   --                       |                |
   --                Basic_Exc_Info & Basic_Exc_Tback
   --                    (B_E_I)          (B_E_TB)

   --           o--
   --  (B_E_I)  |  Exception_Name: <exception name> (as in Exception_Name)
   --           |  Message: <message> (or a null line if no message)
   --           |  PID=nnnn (if != 0)
   --           o--
   --  (B_E_TB) |  Call stack traceback locations:
   --           |  <0xyyyyyyyy 0xyyyyyyyy ...>
   --           o--

   --                  Tailored_Exception_Information
   --                               |
   --                    +----------+----------+
   --                    |                     |
   --             Basic_Exc_Info    &  Tailored_Exc_Tback
   --                                          |
   --                              +-----------+------------+
   --                              |                        |
   --                       Basic_Exc_Tback    Or    Tback_Decorator
   --                     if no decorator set           otherwise

   --  Functions returning String imply secondary stack use, which is a heavy
   --  mechanism requiring run-time support. Besides, some of the routines we
   --  provide here are to be used by the default Last_Chance_Handler, at the
   --  critical point where the runtime is about to be finalized. Since most
   --  of the items we have at hand are of bounded length, we also provide a
   --  procedural interface able to incrementally append the necessary bits to
   --  a preallocated buffer or output them straight to stderr.

   --  The procedural interface is composed of two major sections: a neutral
   --  section for basic types like Address, Character, Natural or String, and
   --  an exception oriented section for the e.g. Basic_Exception_Information.
   --  This is the Append_Info family of procedures below.

   --  Output to stderr is commanded by passing an empty buffer to update, and
   --  care is taken not to overflow otherwise.

   --------------------------------------------
   -- Procedural Interface - Neutral section --
   --------------------------------------------

   procedure Append_Info_Address
     (A    : Address;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Character
     (C    : Character;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Nat
     (N    : Natural;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_NL
     (Info : in out String;
      Ptr  : in out Natural);
   pragma Inline (Append_Info_NL);

   procedure Append_Info_String
     (S    : String;
      Info : in out String;
      Ptr  : in out Natural);

   -------------------------------------------------------
   -- Procedural Interface - Exception oriented section --
   -------------------------------------------------------

   procedure Append_Info_Exception_Name
     (Id   : Exception_Id;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Exception_Name
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Exception_Message
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Basic_Exception_Information
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Basic_Exception_Traceback
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural);

   procedure Append_Info_Exception_Information
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural);

   --  The "functional" interface to the exception information not involving
   --  a traceback decorator uses preallocated intermediate buffers to avoid
   --  the use of secondary stack. Preallocation requires preliminary length
   --  computation, for which a series of functions are introduced:

   ---------------------------------
   -- Length evaluation utilities --
   ---------------------------------

   function Basic_Exception_Info_Maxlength
     (X : Exception_Occurrence) return Natural;

   function Basic_Exception_Tback_Maxlength
     (X : Exception_Occurrence) return Natural;

   function Exception_Info_Maxlength
     (X : Exception_Occurrence) return Natural;

   function Exception_Name_Length
     (Id : Exception_Id) return Natural;

   function Exception_Name_Length
     (X : Exception_Occurrence) return Natural;

   function Exception_Message_Length
     (X : Exception_Occurrence) return Natural;

   --------------------------
   -- Functional Interface --
   --------------------------

   function Basic_Exception_Traceback
     (X : Exception_Occurrence) return String;
   --  Returns an image of the complete call chain associated with an
   --  exception occurrence in its most basic form, that is as a raw sequence
   --  of hexadecimal binary addresses.

   function Tailored_Exception_Traceback
     (X : Exception_Occurrence) return String;
   --  Returns an image of the complete call chain associated with an
   --  exception occurrence, either in its basic form if no decorator is
   --  in place, or as formatted by the decorator otherwise.

   -----------------------------------------------------------------------
   -- Services for the default Last_Chance_Handler and the task wrapper --
   -----------------------------------------------------------------------

   pragma Export
     (Ada, Append_Info_Exception_Message, "__gnat_append_info_e_msg");

   pragma Export
     (Ada, Append_Info_Exception_Information, "__gnat_append_info_e_info");

   pragma Export
     (Ada, Exception_Message_Length, "__gnat_exception_msg_len");

   -------------------------
   -- Append_Info_Address --
   -------------------------

   procedure Append_Info_Address
     (A    : Address;
      Info : in out String;
      Ptr  : in out Natural)
   is
      S : String (1 .. 18);
      P : Natural;
      N : Integer_Address;

      H : constant array (Integer range 0 .. 15) of Character :=
                                                         "0123456789abcdef";
   begin
      P := S'Last;
      N := To_Integer (A);
      loop
         S (P) := H (Integer (N mod 16));
         P := P - 1;
         N := N / 16;
         exit when N = 0;
      end loop;

      S (P - 1) := '0';
      S (P) := 'x';

      Append_Info_String (S (P - 1 .. S'Last), Info, Ptr);
   end Append_Info_Address;

   ---------------------------
   -- Append_Info_Character --
   ---------------------------

   procedure Append_Info_Character
     (C    : Character;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      if Info'Length = 0 then
         To_Stderr (C);
      elsif Ptr < Info'Last then
         Ptr := Ptr + 1;
         Info (Ptr) := C;
      end if;
   end Append_Info_Character;

   ---------------------
   -- Append_Info_Nat --
   ---------------------

   procedure Append_Info_Nat
     (N    : Natural;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      if N > 9 then
         Append_Info_Nat (N / 10, Info, Ptr);
      end if;

      Append_Info_Character
        (Character'Val (Character'Pos ('0') + N mod 10), Info, Ptr);
   end Append_Info_Nat;

   --------------------
   -- Append_Info_NL --
   --------------------

   procedure Append_Info_NL
     (Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      Append_Info_Character (ASCII.LF, Info, Ptr);
   end Append_Info_NL;

   ------------------------
   -- Append_Info_String --
   ------------------------

   procedure Append_Info_String
     (S    : String;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      if Info'Length = 0 then
         To_Stderr (S);
      else
         declare
            Last : constant Natural :=
              Integer'Min (Ptr + S'Length, Info'Last);
         begin
            Info (Ptr + 1 .. Last) := S;
            Ptr := Last;
         end;
      end if;
   end Append_Info_String;

   ---------------------------------------------
   -- Append_Info_Basic_Exception_Information --
   ---------------------------------------------

   --  To ease the maximum length computation, we define and pull out a couple
   --  of string constants:

   BEI_Name_Header : constant String := "Exception name: ";
   BEI_Msg_Header  : constant String := "Message: ";
   BEI_PID_Header  : constant String := "PID: ";

   procedure Append_Info_Basic_Exception_Information
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural)
   is
      Name : String (1 .. Exception_Name_Length (X));
      --  Buffer in which to fetch the exception name, in order to check
      --  whether this is an internal _ABORT_SIGNAL or a regular occurrence.

      Name_Ptr : Natural := Name'First - 1;

   begin
      --  Output exception name and message except for _ABORT_SIGNAL, where
      --  these two lines are omitted.

      Append_Info_Exception_Name (X, Name, Name_Ptr);

      if Name (Name'First) /= '_' then
         Append_Info_String (BEI_Name_Header, Info, Ptr);
         Append_Info_String (Name, Info, Ptr);
         Append_Info_NL (Info, Ptr);

         if Exception_Message_Length (X) /= 0 then
            Append_Info_String (BEI_Msg_Header, Info, Ptr);
            Append_Info_Exception_Message  (X, Info, Ptr);
            Append_Info_NL (Info, Ptr);
         end if;
      end if;

      --  Output PID line if non-zero

      if X.Pid /= 0 then
         Append_Info_String (BEI_PID_Header, Info, Ptr);
         Append_Info_Nat (X.Pid, Info, Ptr);
         Append_Info_NL (Info, Ptr);
      end if;
   end Append_Info_Basic_Exception_Information;

   -------------------------------------------
   -- Basic_Exception_Information_Maxlength --
   -------------------------------------------

   function Basic_Exception_Info_Maxlength
     (X : Exception_Occurrence) return Natural is
   begin
      return
        BEI_Name_Header'Length + Exception_Name_Length (X) + 1
        + BEI_Msg_Header'Length + Exception_Message_Length (X) + 1
        + BEI_PID_Header'Length + 15;
   end Basic_Exception_Info_Maxlength;

   -------------------------------------------
   -- Append_Info_Basic_Exception_Traceback --
   -------------------------------------------

   --  As for Basic_Exception_Information:

   BETB_Header : constant String := "Call stack traceback locations:";

   procedure Append_Info_Basic_Exception_Traceback
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      if X.Num_Tracebacks = 0 then
         return;
      end if;

      Append_Info_String (BETB_Header, Info, Ptr);
      Append_Info_NL (Info, Ptr);

      for J in 1 .. X.Num_Tracebacks loop
         Append_Info_Address (TBE.PC_For (X.Tracebacks (J)), Info, Ptr);
         exit when J = X.Num_Tracebacks;
         Append_Info_Character (' ', Info, Ptr);
      end loop;

      Append_Info_NL (Info, Ptr);
   end Append_Info_Basic_Exception_Traceback;

   -----------------------------------------
   -- Basic_Exception_Traceback_Maxlength --
   -----------------------------------------

   function Basic_Exception_Tback_Maxlength
     (X : Exception_Occurrence) return Natural
   is
      Space_Per_Traceback : constant := 2 + 16 + 1;
      --  Space for "0x" + HHHHHHHHHHHHHHHH + " "
   begin
      return BETB_Header'Length + 1 +
               X.Num_Tracebacks * Space_Per_Traceback + 1;
   end Basic_Exception_Tback_Maxlength;

   ---------------------------------------
   -- Append_Info_Exception_Information --
   ---------------------------------------

   procedure Append_Info_Exception_Information
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      Append_Info_Basic_Exception_Information (X, Info, Ptr);
      Append_Info_Basic_Exception_Traceback   (X, Info, Ptr);
   end Append_Info_Exception_Information;

   ------------------------------
   -- Exception_Info_Maxlength --
   ------------------------------

   function Exception_Info_Maxlength
     (X : Exception_Occurrence) return Natural is
   begin
      return
        Basic_Exception_Info_Maxlength (X)
        + Basic_Exception_Tback_Maxlength (X);
   end Exception_Info_Maxlength;

   -----------------------------------
   -- Append_Info_Exception_Message --
   -----------------------------------

   procedure Append_Info_Exception_Message
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural) is
   begin
      if X.Id = Null_Id then
         raise Constraint_Error;
      end if;

      declare
         Len : constant Natural := Exception_Message_Length (X);
         Msg : constant String (1 .. Len) := X.Msg (1 .. Len);
      begin
         Append_Info_String (Msg, Info, Ptr);
      end;
   end Append_Info_Exception_Message;

   --------------------------------
   -- Append_Info_Exception_Name --
   --------------------------------

   procedure Append_Info_Exception_Name
     (Id   : Exception_Id;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      if Id = Null_Id then
         raise Constraint_Error;
      end if;

      declare
         Len  : constant Natural := Exception_Name_Length (Id);
         Name : constant String (1 .. Len) := To_Ptr (Id.Full_Name) (1 .. Len);
      begin
         Append_Info_String (Name, Info, Ptr);
      end;
   end Append_Info_Exception_Name;

   procedure Append_Info_Exception_Name
     (X    : Exception_Occurrence;
      Info : in out String;
      Ptr  : in out Natural)
   is
   begin
      Append_Info_Exception_Name (X.Id, Info, Ptr);
   end Append_Info_Exception_Name;

   ---------------------------
   -- Exception_Name_Length --
   ---------------------------

   function Exception_Name_Length
     (Id : Exception_Id) return Natural is
   begin
      --  What is stored in the internal Name buffer includes a terminating
      --  null character that we never care about.

      return Id.Name_Length - 1;
   end Exception_Name_Length;

   function Exception_Name_Length
     (X : Exception_Occurrence) return Natural is
   begin
      return Exception_Name_Length (X.Id);
   end Exception_Name_Length;

   ------------------------------
   -- Exception_Message_Length --
   ------------------------------

   function Exception_Message_Length
     (X : Exception_Occurrence) return Natural is
   begin
      return X.Msg_Length;
   end Exception_Message_Length;

   -------------------------------
   -- Basic_Exception_Traceback --
   -------------------------------

   function Basic_Exception_Traceback
     (X : Exception_Occurrence) return String
   is
      Info : aliased String (1 .. Basic_Exception_Tback_Maxlength (X));
      Ptr  : Natural := Info'First - 1;

   begin
      Append_Info_Basic_Exception_Traceback (X, Info, Ptr);
      return Info (Info'First .. Ptr);
   end Basic_Exception_Traceback;

   ---------------------------
   -- Exception_Information --
   ---------------------------

   function Exception_Information
     (X : Exception_Occurrence) return String
   is
      Info : String (1 .. Exception_Info_Maxlength (X));
      Ptr  : Natural := Info'First - 1;

   begin
      Append_Info_Exception_Information (X, Info, Ptr);
      return Info (Info'First .. Ptr);
   end Exception_Information;

   -------------------------
   -- Set_Exception_C_Msg --
   -------------------------

   procedure Set_Exception_C_Msg
     (Id     : Exception_Id;
      Msg1   : System.Address;
      Line   : Integer        := 0;
      Column : Integer        := 0;
      Msg2   : System.Address := System.Null_Address)
   is
      Excep  : constant EOA := Get_Current_Excep.all;
      Remind : Integer;
      Ptr    : Natural;

      procedure Append_Number (Number : Integer);
      --  Append given number to Excep.Msg

      -------------------
      -- Append_Number --
      -------------------

      procedure Append_Number (Number : Integer) is
         Val  : Integer;
         Size : Integer;

      begin
         if Number <= 0 then
            return;
         end if;

         --  Compute the number of needed characters

         Size := 1;
         Val := Number;
         while Val > 0 loop
            Val := Val / 10;
            Size := Size + 1;
         end loop;

         --  If enough characters are available, put the line number

         if Excep.Msg_Length <= Exception_Msg_Max_Length - Size then
            Excep.Msg (Excep.Msg_Length + 1) := ':';
            Excep.Msg_Length := Excep.Msg_Length + Size;
            Val := Number;
            Size := 0;

            while Val > 0 loop
               Remind := Val rem 10;
               Val := Val / 10;
               Excep.Msg (Excep.Msg_Length - Size) :=
                 Character'Val (Remind + Character'Pos ('0'));
               Size := Size + 1;
            end loop;
         end if;
      end Append_Number;

   --  Start of processing for Set_Exception_C_Msg

   begin
      Exception_Propagation.Setup_Exception (Excep, Excep);
      Excep.Exception_Raised := False;
      Excep.Id               := Id;
      Excep.Num_Tracebacks   := 0;
      Excep.Pid              := Local_Partition_ID;
      Excep.Msg_Length       := 0;
      Excep.Cleanup_Flag     := False;

      while To_Ptr (Msg1) (Excep.Msg_Length + 1) /= ASCII.NUL
        and then Excep.Msg_Length < Exception_Msg_Max_Length
      loop
         Excep.Msg_Length := Excep.Msg_Length + 1;
         Excep.Msg (Excep.Msg_Length) := To_Ptr (Msg1) (Excep.Msg_Length);
      end loop;

      Append_Number (Line);
      Append_Number (Column);

      --  Append second message if present

      if Msg2 /= System.Null_Address
        and then Excep.Msg_Length + 1 < Exception_Msg_Max_Length
      then
         Excep.Msg_Length := Excep.Msg_Length + 1;
         Excep.Msg (Excep.Msg_Length) := ' ';

         Ptr := 1;
         while To_Ptr (Msg2) (Ptr) /= ASCII.NUL
           and then Excep.Msg_Length < Exception_Msg_Max_Length
         loop
            Excep.Msg_Length := Excep.Msg_Length + 1;
            Excep.Msg (Excep.Msg_Length) := To_Ptr (Msg2) (Ptr);
            Ptr := Ptr + 1;
         end loop;
      end if;
   end Set_Exception_C_Msg;

   -----------------------
   -- Set_Exception_Msg --
   -----------------------

   procedure Set_Exception_Msg
     (Id      : Exception_Id;
      Message : String)
   is
      Len   : constant Natural :=
                Natural'Min (Message'Length, Exception_Msg_Max_Length);
      First : constant Integer := Message'First;
      Excep  : constant EOA := Get_Current_Excep.all;

   begin
      Exception_Propagation.Setup_Exception (Excep, Excep);
      Excep.Exception_Raised := False;
      Excep.Msg_Length       := Len;
      Excep.Msg (1 .. Len)   := Message (First .. First + Len - 1);
      Excep.Id               := Id;
      Excep.Num_Tracebacks   := 0;
      Excep.Pid              := Local_Partition_ID;
      Excep.Cleanup_Flag     := False;

   end Set_Exception_Msg;

   ----------------------------------
   -- Tailored_Exception_Traceback --
   ----------------------------------

   function Tailored_Exception_Traceback
     (X : Exception_Occurrence) return String
   is
      --  We reference the decorator *wrapper* here and not the decorator
      --  itself. The purpose of the local variable Wrapper is to prevent a
      --  potential race condition in the code below. The atomicity of this
      --  assignment is enforced by pragma Atomic in System.Soft_Links.

      --  The potential race condition here, if no local variable was used,
      --  relates to the test upon the wrapper's value and the call, which
      --  are not performed atomically. With the local variable, potential
      --  changes of the wrapper's global value between the test and the
      --  call become inoffensive.

      Wrapper : constant Traceback_Decorator_Wrapper_Call :=
                  Traceback_Decorator_Wrapper;

   begin
      if Wrapper = null then
         return Basic_Exception_Traceback (X);
      else
         return Wrapper.all (X.Tracebacks'Address, X.Num_Tracebacks);
      end if;
   end Tailored_Exception_Traceback;

   ------------------------------------
   -- Tailored_Exception_Information --
   ------------------------------------

   function Tailored_Exception_Information
     (X : Exception_Occurrence) return String
   is
      --  The tailored exception information is the basic information
      --  associated with the tailored call chain backtrace.

      Tback_Info : constant String  := Tailored_Exception_Traceback (X);
      Tback_Len  : constant Natural := Tback_Info'Length;

      Info : String (1 .. Basic_Exception_Info_Maxlength (X) + Tback_Len);
      Ptr  : Natural := Info'First - 1;

   begin
      Append_Info_Basic_Exception_Information (X, Info, Ptr);
      Append_Info_String (Tback_Info, Info, Ptr);
      return Info (Info'First .. Ptr);
   end Tailored_Exception_Information;

end Exception_Data;