1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                               E R R O U T                                --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2003 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 2,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- GNAT was originally developed  by the GNAT team at  New York University. --
23-- Extensive contributions were provided by Ada Core Technologies Inc.      --
24--                                                                          --
25------------------------------------------------------------------------------
26
27--  This package contains the routines to output error messages. They
28--  are basically system independent, however in some environments, e.g.
29--  when the parser is embedded into an editor, it may be appropriate
30--  to replace the implementation of this package.
31
32with Err_Vars;
33with Erroutc;
34with Table;
35with Types; use Types;
36with Uintp; use Uintp;
37
38with System;
39
40package Errout is
41
42   Serious_Errors_Detected : Nat renames Err_Vars.Serious_Errors_Detected;
43   --  This is a count of errors that are serious enough to stop expansion,
44   --  and hence to prevent generation of an object file even if the
45   --  switch -gnatQ is set.
46
47   Total_Errors_Detected : Nat renames Err_Vars.Total_Errors_Detected;
48   --  Number of errors detected so far. Includes count of serious errors
49   --  and non-serious errors, so this value is always greater than or
50   --  equal to the Serious_Errors_Detected value.
51
52   Warnings_Detected : Nat renames Err_Vars.Warnings_Detected;
53   --  Number of warnings detected
54
55   Configurable_Run_Time_Violations : Nat := 0;
56   --  Count of configurable run time violations so far. This is used to
57   --  suppress certain cascaded error messages when we know that we may not
58   --  have fully expanded some items, due to high integrity violations (i.e.
59   --  the use of constructs not permitted by the library in use, or
60   --  improper constructs in No_Run_Time mode).
61
62   type Compiler_State_Type is (Parsing, Analyzing);
63   Compiler_State : Compiler_State_Type;
64   --  Indicates current state of compilation. This is put in the Errout
65   --  spec because it affects the action of the error message handling.
66   --  In particular, an attempt is made by Errout to suppress cascaded
67   --  error messages in Parsing mode, but not in the other modes.
68
69   Current_Error_Source_File : Source_File_Index
70     renames Err_Vars.Current_Error_Source_File;
71   --  Id of current messages. Used to post file name when unit changes. This
72   --  is initialized to Main_Source_File at the start of a compilation, which
73   --  means that no file names will be output unless there are errors in units
74   --  other than the main unit. However, if the main unit has a pragma
75   --  Source_Reference line, then this is initialized to No_Source_File,
76   --  to force an initial reference to the real source file name.
77
78   Raise_Exception_On_Error : Nat renames Err_Vars.Raise_Exception_On_Error;
79   --  If this value is non-zero, then any attempt to generate an error
80   --  message raises the exception Error_Msg_Exception, and the error
81   --  message is not output. This is used for defending against junk
82   --  resulting from illegalities, and also for substitution of more
83   --  appropriate error messages from higher semantic levels. It is
84   --  a counter so that the increment/decrement protocol nests neatly.
85
86   Error_Msg_Exception : exception renames Err_Vars.Error_Msg_Exception;
87   --  Exception raised if Raise_Exception_On_Error is true
88
89   -----------------------------------
90   -- Suppression of Error Messages --
91   -----------------------------------
92
93   --  In an effort to reduce the impact of redundant error messages, the
94   --  error output routines in this package normally suppress certain
95   --  classes of messages as follows:
96
97   --    1.  Identical messages placed at the same point in the text. Such
98   --        duplicate error message result for example from rescanning
99   --        sections of the text that contain lexical errors. Only one of
100   --        such a set of duplicate messages is output, and the rest are
101   --        suppressed.
102
103   --    2.  If more than one parser message is generated for a single source
104   --        line, then only the first message is output, the remaining
105   --        messages on the same line are suppressed.
106
107   --    3.  If a message is posted on a node for which a message has been
108   --        previously posted, then only the first message is retained. The
109   --        Error_Posted flag is used to detect such multiple postings. Note
110   --        that this only applies to semantic messages, since otherwise
111   --        for parser messages, this would be a special case of case 2.
112
113   --    4.  If a message is posted on a node whose Etype or Entity
114   --        fields reference entities on which an error message has
115   --        already been placed, as indicated by the Error_Posted flag
116   --        being set on these entities, then the message is suppressed.
117
118   --    5.  If a message attempts to insert an Error node, or a direct
119   --        reference to the Any_Type node, then the message is suppressed.
120
121   --  This normal suppression action may be overridden in cases 2-5 (but not
122   --  in case 1) by setting All_Errors mode, or by setting the special
123   --  unconditional message insertion character (!) at the end of the message
124   --  text as described below.
125
126   ---------------------------------------------------------
127   -- Error Message Text and Message Insertion Characters --
128   ---------------------------------------------------------
129
130   --  Error message text strings are composed of lower case letters, digits
131   --  and the special characters space, comma, period, colon and semicolon,
132   --  apostrophe and parentheses. Special insertion characters can also
133   --  appear which cause the error message circuit to modify the given
134   --  string as follows:
135
136   --    Insertion character % (Percent: insert name from Names table)
137   --      The character % is replaced by the text for the name specified by
138   --      the Name_Id value stored in Error_Msg_Name_1. A blank precedes
139   --      the name if it is preceded by a non-blank character other than a
140   --      left parenthesis. The name is enclosed in quotes unless manual
141   --      quotation mode is set. If the Name_Id is set to No_Name, then
142   --      no insertion occurs; if the Name_Id is set to Error_Name, then
143   --      the string <error> is inserted. A second and third % may appear
144   --      in a single message, similarly replaced by the names which are
145   --      specified by the Name_Id values stored in Error_Msg_Name_2 and
146   --      Error_Msg_Name_3. The names are decoded and cased according to
147   --      the current identifier casing mode.
148
149   --    Insertion character $ (Dollar: insert unit name from Names table)
150   --      The character $ is treated similarly to %, except that the name
151   --      is obtained from the Unit_Name_Type value in Error_Msg_Unit_1
152   --      and Error_Msg_Unit_2, as provided by Get_Unit_Name_String in
153   --      package Uname. Note that this name includes the postfix (spec)
154   --      or (body) strings. If this postfix is not required, use the
155   --      normal % insertion for the unit name.
156
157   --    Insertion character { (Left brace: insert literally from names table)
158   --      The character { is treated similarly to %, except that the
159   --      name is output literally as stored in the names table without
160   --      adjusting the casing. This can be used for file names and in
161   --      other situations where the name string is to be output unchanged.
162
163   --    Insertion character * (Asterisk, insert reserved word name)
164   --      The insertion character * is treated exactly like % except that
165   --      the resulting name is cased according to the default conventions
166   --      for reserved words (see package Scans).
167
168   --    Insertion character & (Ampersand: insert name from node)
169   --      The insertion character & is treated similarly to %, except that
170   --      the name is taken from the Chars field of the given node, and may
171   --      refer to a child unit name, or a selected component. The casing
172   --      is, if possible, taken from the original source reference, which
173   --      is obtained from the Sloc field of the given node or nodes. If no
174   --      Sloc is available (happens e.g. for nodes in package Standard),
175   --      then the default case (see Scans spec) is used. The nodes to be
176   --      used are stored in Error_Msg_Node_1, Error_Msg_Node_2. No insertion
177   --      occurs for the Empty node, and the Error node results in the
178   --      insertion of the characters <error>. In addition, if the special
179   --      global variable Error_Msg_Qual_Level is non-zero, then the
180   --      reference will include up to the given number of levels of
181   --      qualification, using the scope chain.
182
183   --    Insertion character # (Pound: insert line number reference)
184   --      The character # is replaced by the string indicating the source
185   --      position stored in Error_Msg_Sloc. There are three cases:
186   --
187   --        for package Standard:           in package Standard
188   --        for locations in current file:  at line nnn:ccc
189   --        for locations in other files:   at filename:nnn:ccc
190   --
191   --      By convention, the # insertion character is only used at the end
192   --      of an error message, so the above strings only appear as the last
193   --      characters of an error message.
194
195   --    Insertion character } (Right brace: insert type reference)
196   --      The character } is replaced by a string describing the type
197   --      referenced by the entity whose Id is stored in Error_Msg_Node_1.
198   --      the string gives the name or description of the type, and also
199   --      where appropriate the location of its declaration. Special
200   --      cases like "some integer type" are handled appropriately. Only
201   --      one } is allowed in a message, since there is not enough room
202   --      for two (the insertion can be quite long, including a file name)
203   --      In addition, if the special global variable Error_Msg_Qual_Level
204   --      is non-zero, then the reference will include up to the given
205   --      number of levels of qualification, using the scope chain.
206
207   --    Insertion character @ (At: insert column number reference)
208   --      The character @ is replaced by null if the RM_Column_Check mode is
209   --      off (False). If the switch is on (True), then @ is replaced by the
210   --      text string " in column nnn" where nnn is the decimal representation
211   --      of the column number stored in Error_Msg_Col plus one (the plus one
212   --      is because the number is stored 0-origin and displayed 1-origin).
213
214   --    Insertion character ^ (Carret: insert integer value)
215   --      The character ^ is replaced by the decimal conversion of the Uint
216   --      value stored in Error_Msg_Uint_1, with a possible leading minus.
217   --      A second ^ may occur in the message, in which case it is replaced
218   --      by the decimal conversion of the Uint value in Error_Msg_Uint_2.
219
220   --    Insertion character > (Right bracket, run time name)
221   --      The character > is replaced by a string of the form (name) if
222   --      Targparm scanned out a Run_Time_Name (see package Targparm for
223   --      details). The name is enclosed in parentheses and output in mixed
224   --      case mode (upper case after any space in the name). If no run time
225   --      name is defined, this insertion character has no effect.
226
227   --    Insertion character ! (Exclamation: unconditional message)
228   --      The character ! appearing as the last character of a message makes
229   --      the message unconditional which means that it is output even if it
230   --      would normally be suppressed. See section above for a description
231   --      of the cases in which messages are normally suppressed.
232
233   --    Insertion character ? (Question: warning message)
234   --      The character ? appearing anywhere in a message makes the message
235   --      a warning instead of a normal error message, and the text of the
236   --      message will be preceded by "Warning:" instead of "Error:" The
237   --      handling of warnings if further controlled by the Warning_Mode
238   --      option (-w switch), see package Opt for further details, and
239   --      also by the current setting from pragma Warnings. This pragma
240   --      applies only to warnings issued from the semantic phase (not
241   --      the parser), but currently all relevant warnings are posted
242   --      by the semantic phase anyway. Messages starting with (style)
243   --      are also treated as warning messages.
244
245   --    Insertion character A-Z (Upper case letter: Ada reserved word)
246   --      If two or more upper case letters appear in the message, they are
247   --      taken as an Ada reserved word, and are converted to the default
248   --      case for reserved words (see Scans package spec). Surrounding
249   --      quotes are added unless manual quotation mode is currently set.
250
251   --    Insertion character ` (Backquote: set manual quotation mode)
252   --      The backquote character always appears in pairs. Each backquote
253   --      of the pair is replaced by a double quote character. In addition,
254   --      Any reserved keywords, or name insertions between these backquotes
255   --      are not surrounded by the usual automatic double quotes. See the
256   --      section below on manual quotation mode for further details.
257
258   --    Insertion character ' (Quote: literal character)
259   --      Precedes a character which is placed literally into the message.
260   --      Used to insert characters into messages that are one of the
261   --      insertion characters defined here. Also useful in inserting
262   --      sequences of upper case letters (e.g. RM) which are not to be
263   --      treated as keywords.
264
265   --    Insertion character \ (Backslash: continuation message)
266   --      Indicates that the message is a continuation of a message
267   --      previously posted. This is used to ensure that such groups
268   --      of messages are treated as a unit. The \ character must be
269   --      the first character of the message text.
270
271   --    Insertion character | (vertical bar, non-serious error)
272   --      By default, error messages (other than warning messages) are
273   --      considered to be fatal error messages which prevent expansion
274   --      or generation of code in the presence of the -gnatQ switch.
275   --      If the insertion character | appears, the message is considered
276   --      to be non-serious, and does not cause Serious_Errors_Detected
277   --      to be incremented (so expansion is not prevented by such a msg).
278
279   -----------------------------------------------------
280   -- Global Values Used for Error Message Insertions --
281   -----------------------------------------------------
282
283   --  The following global variables are essentially additional parameters
284   --  passed to the error message routine for insertion sequences described
285   --  above. The reason these are passed globally is that the insertion
286   --  mechanism is essentially an untyped one in which the appropriate
287   --  variables are set dependingon the specific insertion characters used.
288
289   Error_Msg_Col : Column_Number renames Err_Vars.Error_Msg_Col;
290   --  Column for @ insertion character in message
291
292   Error_Msg_Uint_1 : Uint renames Err_Vars.Error_Msg_Uint_1;
293   Error_Msg_Uint_2 : Uint renames Err_Vars.Error_Msg_Uint_2;
294   --  Uint values for ^ insertion characters in message
295
296   Error_Msg_Sloc : Source_Ptr renames Err_Vars.Error_Msg_Sloc;
297   --  Source location for # insertion character in message
298
299   Error_Msg_Name_1 : Name_Id renames Err_Vars.Error_Msg_Name_1;
300   Error_Msg_Name_2 : Name_Id renames Err_Vars.Error_Msg_Name_2;
301   Error_Msg_Name_3 : Name_Id renames Err_Vars.Error_Msg_Name_3;
302   --  Name_Id values for % insertion characters in message
303
304   Error_Msg_Unit_1 : Name_Id renames Err_Vars.Error_Msg_Unit_1;
305   Error_Msg_Unit_2 : Name_Id renames Err_Vars.Error_Msg_Unit_2;
306   --  Name_Id values for $ insertion characters in message
307
308   Error_Msg_Node_1 : Node_Id renames Err_Vars.Error_Msg_Node_1;
309   Error_Msg_Node_2 : Node_Id renames Err_Vars.Error_Msg_Node_2;
310   --  Node_Id values for & insertion characters in message
311
312   Error_Msg_Qual_Level : Int renames Err_Vars.Error_Msg_Qual_Level;
313   --  Number of levels of qualification required for type name (see the
314   --  description of the } insertion character. Note that this value does
315   --  note get reset by any Error_Msg call, so the caller is responsible
316   --  for resetting it.
317
318   -----------------------------------------------------
319   -- Format of Messages and Manual Quotation Control --
320   -----------------------------------------------------
321
322   --  Messages are generally all in lower case, except for inserted names
323   --  and appear in one of the following three forms:
324
325   --    error: text
326   --    warning: text
327
328   --  The prefixes error and warning are supplied automatically (depending
329   --  on the use of the ? insertion character), and the call to the error
330   --  message routine supplies the text. The "error: " prefix is omitted
331   --  in brief error message formats.
332
333   --  Reserved Ada keywords in the message are in the default keyword case
334   --  (determined from the given source program), surrounded by quotation
335   --  marks. This is achieved by spelling the reserved word in upper case
336   --  letters, which is recognized as a request for insertion of quotation
337   --  marks by the error text processor. Thus for example:
338
339   --    Error_Msg_AP ("IS expected");
340
341   --  would result in the output of one of the following:
342
343   --    error: "is" expected
344   --    error: "IS" expected
345   --    error: "Is" expected
346
347   --  the choice between these being made by looking at the casing convention
348   --  used for keywords (actually the first compilation unit keyword) in the
349   --  source file.
350
351   --  In the case of names, the default mode for the error text processor
352   --  is to surround the name by quotation marks automatically. The case
353   --  used for the identifier names is taken from the source program where
354   --  possible, and otherwise is the default casing convention taken from
355   --  the source file usage.
356
357   --  In some cases, better control over the placement of quote marks is
358   --  required. This is achieved using manual quotation mode. In this mode,
359   --  one or more insertion sequences is surrounded by backquote characters.
360   --  The backquote characters are output as double quote marks, and normal
361   --  automatic insertion of quotes is suppressed between the double quotes.
362   --  For example:
363
364   --    Error_Msg_AP ("`END &;` expected");
365
366   --  generates a message like
367
368   --    error: "end Open_Scope;" expected
369
370   --  where the node specifying the name Open_Scope has been stored in
371   --  Error_Msg_Node_1 prior to the call. The great majority of error
372   --  messages operates in normal quotation mode.
373
374   --  Note: the normal automatic insertion of spaces before insertion
375   --  sequences (such as those that come from & and %) is suppressed in
376   --  manual quotation mode, so blanks, if needed as in the above example,
377   --  must be explicitly present.
378
379   ----------------------------
380   -- Message ID Definitions --
381   ----------------------------
382
383   subtype Error_Msg_Id is Erroutc.Error_Msg_Id;
384   function "=" (Left, Right : Error_Msg_Id) return Boolean
385     renames Erroutc."=";
386   --  A type used to represent specific error messages. Used by the clients
387   --  of this package only in the context of the Get_Error_Id and
388   --  Change_Error_Text subprograms.
389
390   No_Error_Msg : constant Error_Msg_Id := Erroutc.No_Error_Msg;
391   --  A constant which is different from any value returned by Get_Error_Id.
392   --  Typically used by a client to indicate absense of a saved Id value.
393
394   function Get_Msg_Id return Error_Msg_Id renames Erroutc.Get_Msg_Id;
395   --  Returns the Id of the message most recently posted using one of the
396   --  Error_Msg routines.
397
398   function Get_Location (E : Error_Msg_Id) return Source_Ptr
399     renames Erroutc.Get_Location;
400   --  Returns the flag location of the error message with the given id E.
401
402   ------------------------
403   -- List Pragmas Table --
404   ------------------------
405
406   --  When a pragma Page or pragma List is encountered by the parser, an
407   --  entry is made in the following table. This table is then used to
408   --  control the full listing if one is being generated. Note that the
409   --  reason we do the processing in the parser is so that we get proper
410   --  listing control even in syntax check only mode.
411
412   type List_Pragma_Type is (List_On, List_Off, Page);
413
414   type List_Pragma_Record is record
415      Ptyp : List_Pragma_Type;
416      Ploc : Source_Ptr;
417   end record;
418
419   --  Note: Ploc points to the terminating semicolon in the List_Off and
420   --  Page cases, and to the pragma keyword for List_On. In the case of
421   --  a pragma List_Off, a List_On entry is also made in the table,
422   --  pointing to the pragma keyword. This ensures that, as required,
423   --  a List (Off) pragma is listed even in list off mode.
424
425   package List_Pragmas is new Table.Table (
426     Table_Component_Type => List_Pragma_Record,
427     Table_Index_Type     => Int,
428     Table_Low_Bound      => 1,
429     Table_Initial        => 50,
430     Table_Increment      => 200,
431     Table_Name           => "List_Pragmas");
432
433   ---------------------------
434   -- Ignore_Errors Feature --
435   ---------------------------
436
437   --  In certain cases, notably for optional subunits, the compiler operates
438   --  in a mode where errors are to be ignored, and the whole unit is to be
439   --  considered as not present. To implement this we provide the following
440   --  flag to enable special handling, where error messages are suppressed,
441   --  but the Fatal_Error flag will still be set in the normal manner.
442
443   Ignore_Errors_Enable : Nat := 0;
444   --  Triggering switch. If non-zero, then ignore errors mode is activated.
445   --  This is a counter to allow convenient nesting of enable/disable.
446
447   ------------------------------
448   -- Error Output Subprograms --
449   ------------------------------
450
451   procedure Initialize;
452   --  Initializes for output of error messages. Must be called for each
453   --  source file before using any of the other routines in the package.
454
455   procedure Finalize;
456   --  Finalize processing of error messages for one file and output message
457   --  indicating the number of detected errors.
458
459   procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);
460   --  Output a message at specified location. Can be called from the parser
461   --  or the semantic analyzer.
462
463   procedure Error_Msg_S (Msg : String);
464   --  Output a message at current scan pointer location. This routine can be
465   --  called only from the parser, since it references Scan_Ptr.
466
467   procedure Error_Msg_AP (Msg : String);
468   --  Output a message just after the previous token. This routine can be
469   --  called only from the parser, since it references Prev_Token_Ptr.
470
471   procedure Error_Msg_BC (Msg : String);
472   --  Output a message just before the current token. Note that the important
473   --  difference between this and the previous routine is that the BC case
474   --  posts a flag on the current line, whereas AP can post a flag at the
475   --  end of the preceding line. This routine can be called only from the
476   --  parser, since it references Token_Ptr.
477
478   procedure Error_Msg_SC (Msg : String);
479   --  Output a message at the start of the current token, unless we are at
480   --  the end of file, in which case we always output the message after the
481   --  last real token in the file. This routine can be called only from the
482   --  parser, since it references Token_Ptr.
483
484   procedure Error_Msg_SP (Msg : String);
485   --  Output a message at the start of the previous token. This routine can
486   --  be called only from the parser, since it references Prev_Token_Ptr.
487
488   procedure Error_Msg_N (Msg : String; N : Node_Or_Entity_Id);
489   --  Output a message at the Sloc of the given node. This routine can be
490   --  called from the parser or the semantic analyzer, although the call
491   --  from the latter is much more common (and is the most usual way of
492   --  generating error messages from the analyzer). The message text may
493   --  contain a single & insertion, which will reference the given node.
494   --  The message is suppressed if the node N already has a message posted,
495   --  or if it is a warning and warnings and N is an entity node for which
496   --  warnings are suppressed.
497
498   procedure Error_Msg_F (Msg : String; N : Node_Id);
499   --  Similar to Error_Msg_N except that the message is placed on the
500   --  first node of the construct N (First_Node (N)).
501
502   procedure Error_Msg_NE
503     (Msg : String;
504      N   : Node_Or_Entity_Id;
505      E   : Node_Or_Entity_Id);
506   --  Output a message at the Sloc of the given node N, with an insertion of
507   --  the name from the given entity node E. This is used by the semantic
508   --  routines, where this is a common error message situation. The Msg
509   --  text will contain a & or } as usual to mark the insertion point.
510   --  This routine can be called from the parser or the analyzer.
511
512   procedure Error_Msg_FE
513     (Msg : String;
514      N   : Node_Id;
515      E   : Node_Or_Entity_Id);
516   --  Same as Error_Msg_NE, except that the message is placed on the first
517   --  node of the construct N (First_Node (N)).
518
519   procedure Error_Msg_NEL
520     (Msg           : String;
521      N             : Node_Or_Entity_Id;
522      E             : Node_Or_Entity_Id;
523      Flag_Location : Source_Ptr);
524   --  Exactly the same as Error_Msg_NE, except that the flag is placed at
525   --  the specified Flag_Location instead of at Sloc (N).
526
527   procedure Error_Msg_NW
528     (Eflag : Boolean;
529      Msg   : String;
530      N     : Node_Or_Entity_Id);
531   --  This routine is used for posting a message conditionally. The message
532   --  is posted (with the same effect as Error_Msg_N (Msg, N) if and only
533   --  if Eflag is True and if the node N is within the main extended source
534   --  unit. Typically this is a warning mode flag.
535
536   procedure Change_Error_Text (Error_Id : Error_Msg_Id; New_Msg : String);
537   --  The error message text of the message identified by Id is replaced by
538   --  the given text. This text may contain insertion characters in the
539   --  usual manner, and need not be the same length as the original text.
540
541   function First_Node (C : Node_Id) return Node_Id;
542   --  Given a construct C, finds the first node in the construct, i.e. the
543   --  one with the lowest Sloc value. This is useful in placing error msgs.
544
545   procedure Purge_Messages (From : Source_Ptr; To : Source_Ptr)
546     renames Erroutc.Purge_Messages;
547   --  All error messages whose location is in the range From .. To (not
548   --  including the end points) will be deleted from the error listing.
549
550   procedure Remove_Warning_Messages (N : Node_Id);
551   --  Remove any warning messages corresponding to the Sloc of N or any
552   --  of its descendent nodes. No effect if no such warnings.
553
554   procedure Remove_Warning_Messages (L : List_Id);
555   --  Remove warnings on all elements of a list.
556
557   procedure Set_Ignore_Errors (To : Boolean);
558   --  Following a call to this procedure with To=True, all error calls are
559   --  ignored. A call with To=False restores the default treatment in which
560   --  error calls are treated as usual (and as described in this spec).
561
562   procedure Set_Warnings_Mode_Off (Loc : Source_Ptr)
563     renames Erroutc.Set_Warnings_Mode_Off;
564   --  Called in response to a pragma Warnings (Off) to record the source
565   --  location from which warnings are to be turned off.
566
567   procedure Set_Warnings_Mode_On (Loc : Source_Ptr)
568     renames Erroutc.Set_Warnings_Mode_On;
569   --  Called in response to a pragma Warnings (On) to record the source
570   --  location from which warnings are to be turned back on.
571
572   function Compilation_Errors return Boolean
573     renames Erroutc.Compilation_Errors;
574   --  Returns true if errors have been detected, or warnings in -gnatwe
575   --  (treat warnings as errors) mode.
576
577   procedure Error_Msg_CRT (Feature : String; N : Node_Id);
578   --  Posts a non-fatal message on node N saying that the feature
579   --  identified by the Feature argument is not supported in either
580   --  configurable run-time mode or no run-time mode (as appropriate).
581   --  In the former case, the name of the library is output if available.
582
583   procedure dmsg (Id : Error_Msg_Id) renames Erroutc.dmsg;
584   --  Debugging routine to dump an error message
585
586   ------------------------------------
587   -- Utility Interface for Back End --
588   ------------------------------------
589
590   --  The following subprograms can be used by the back end for the purposes
591   --  of concocting error messages that are not output via Errout, e.g. the
592   --  messages generated by the gcc back end.
593
594   procedure Set_Identifier_Casing
595     (Identifier_Name : System.Address;
596      File_Name       : System.Address);
597   --  The identifier is a null terminated string that represents the name
598   --  of an identifier appearing in the source program. File_Name is a null
599   --  terminated string giving the corresponding file name for the identifier
600   --  as obtained from the front end by the use of Full_Debug_Name to the
601   --  source file referenced by the corresponding source location value.
602   --  On return, the name is in Name_Buffer, null terminated with Name_Len
603   --  set. This name is the identifier name as passed, cased according to
604   --  the default identifier casing for the given file.
605
606end Errout;
607