Subversion Repositories openrisc_2011-10-31

------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                               E R R O U T                                --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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.                                     --

--                                                                          --

-- You should have received a copy of the GNU General Public License along  --

-- with this program; see file COPYING3.  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.      --

--                                                                          --

------------------------------------------------------------------------------

--  This package contains the routines to output error messages. They are

--  basically system independent, however in some environments, e.g. when the

--  parser is embedded into an editor, it may be appropriate to replace the

--  implementation of this package.

with Err_Vars;

with Erroutc;

with Namet;    use Namet;

with Table;

with Types;    use Types;

with Uintp;    use Uintp;

with System;

package Errout is

   Serious_Errors_Detected : Nat renames Err_Vars.Serious_Errors_Detected;

   --  This is a count of errors that are serious enough to stop expansion,

   --  and hence to prevent generation of an object file even if the switch

   --  -gnatQ is set.

   Total_Errors_Detected : Nat renames Err_Vars.Total_Errors_Detected;

   --  Number of errors detected so far. Includes count of serious errors and

   --  non-serious errors, so this value is always greater than or equal to

   --  the Serious_Errors_Detected value.

   Warnings_Detected : Nat renames Err_Vars.Warnings_Detected;

   --  Number of warnings detected

   Configurable_Run_Time_Violations : Nat := 0;

   --  Count of configurable run time violations so far. This is used to

   --  suppress certain cascaded error messages when we know that we may not

   --  have fully expanded some items, due to high integrity violations (i.e.

   --  the use of constructs not permitted by the library in use, or improper

   --  constructs in No_Run_Time mode).

   type Compiler_State_Type is (Parsing, Analyzing);

   Compiler_State : Compiler_State_Type;

   --  Indicates current state of compilation. This is put in the Errout spec

   --  because it affects the action of the error message handling. In

   --  particular, an attempt is made by Errout to suppress cascaded error

   --  messages in Parsing mode, but not in the other modes.

   Current_Error_Source_File : Source_File_Index

     renames Err_Vars.Current_Error_Source_File;

   --  Id of current messages. Used to post file name when unit changes. This

   --  is initialized to Main_Source_File at the start of a compilation, which

   --  means that no file names will be output unless there are errors in

   --  units other than the main unit. However, if the main unit has a pragma

   --  Source_Reference line, then this is initialized to No_Source_File, to

   --  force an initial reference to the real source file name.

   Raise_Exception_On_Error : Nat renames Err_Vars.Raise_Exception_On_Error;

   --  If this value is non-zero, then any attempt to generate an error

   --  message raises the exception Error_Msg_Exception, and the error message

   --  is not output. This is used for defending against junk resulting from

   --  illegalities, and also for substitution of more appropriate error

   --  messages from higher semantic levels. It is a counter so that the

   --  increment/decrement protocol nests neatly.

   Error_Msg_Exception : exception renames Err_Vars.Error_Msg_Exception;

   --  Exception raised if Raise_Exception_On_Error is true

   -----------------------------------

   -- Suppression of Error Messages --

   -----------------------------------

   --  In an effort to reduce the impact of redundant error messages, the

   --  error output routines in this package normally suppress certain

   --  classes of messages as follows:

   --    1.  Identical messages placed at the same point in the text. Such

   --        duplicate error message result for example from rescanning

   --        sections of the text that contain lexical errors. Only one of

   --        such a set of duplicate messages is output, and the rest are

   --        suppressed.

   --    2.  If more than one parser message is generated for a single source

   --        line, then only the first message is output, the remaining

   --        messages on the same line are suppressed.

   --    3.  If a message is posted on a node for which a message has been

   --        previously posted, then only the first message is retained. The

   --        Error_Posted flag is used to detect such multiple postings. Note

   --        that this only applies to semantic messages, since otherwise

   --        for parser messages, this would be a special case of case 2.

   --    4.  If a message is posted on a node whose Etype or Entity

   --        fields reference entities on which an error message has

   --        already been placed, as indicated by the Error_Posted flag

   --        being set on these entities, then the message is suppressed.

   --    5.  If a message attempts to insert an Error node, or a direct

   --        reference to the Any_Type node, then the message is suppressed.

   --    6.  Note that cases 2-5 only apply to error messages, not warning

   --        messages. Warning messages are only suppressed for case 1, and

   --        when they come from other than the main extended unit.

   --  This normal suppression action may be overridden in cases 2-5 (but not

   --  in case 1) by setting All_Errors mode, or by setting the special

   --  unconditional message insertion character (!) at the end of the message

   --  text as described below.

   ---------------------------------------------------------

   -- Error Message Text and Message Insertion Characters --

   ---------------------------------------------------------

   --  Error message text strings are composed of lower case letters, digits

   --  and the special characters space, comma, period, colon and semicolon,

   --  apostrophe and parentheses. Special insertion characters can also

   --  appear which cause the error message circuit to modify the given

   --  string as follows:

   --    Insertion character % (Percent: insert name from Names table)

   --      The character % is replaced by the text for the name specified by

   --      the Name_Id value stored in Error_Msg_Name_1. A blank precedes the

   --      name if it is preceded by a non-blank character other than left

   --      parenthesis. The name is enclosed in quotes unless manual quotation

   --      mode is set. If the Name_Id is set to No_Name, then no insertion

   --      occurs; if the Name_Id is set to Error_Name, then the string

   --      <error> is inserted. A second and third % may appear in a single

   --      message, similarly replaced by the names which are specified by the

   --      Name_Id values stored in Error_Msg_Name_2 and Error_Msg_Name_3. The

   --      names are decoded and cased according to the current identifier

   --      casing mode. Note: if a unit name ending with %b or %s is passed

   --      for this kind of insertion, this suffix is simply stripped. Use a

   --      unit name insertion ($) to process the suffix.

   --    Insertion character %% (Double percent: insert literal name)

   --      The character sequence %% acts as described above for %, except

   --      that the name is simply obtained with Get_Name_String and is not

   --      decoded or cased, it is inserted literally from the names table.

   --      A trailing %b or %s is not treated specially.

   --    Insertion character $ (Dollar: insert unit name from Names table)

   --      The character $ is treated similarly to %, except that the name is

   --      obtained from the Unit_Name_Type value in Error_Msg_Unit_1 and

   --      Error_Msg_Unit_2, as provided by Get_Unit_Name_String in package

   --      Uname. Note that this name includes the postfix (spec) or (body)

   --      strings. If this postfix is not required, use the normal %

   --      insertion for the unit name.

   --    Insertion character { (Left brace: insert file name from names table)

   --      The character { is treated similarly to %, except that the input

   --      value is a File_Name_Type value stored in Error_Msg_File_1 or

   --      Error_Msg_File_2 or Error_Msg_File_3. The value is output literally,

   --      enclosed in quotes as for %, but the case is not modified, the

   --      insertion is the exact string stored in the names table without

   --      adjusting the casing.

   --    Insertion character * (Asterisk, insert reserved word name)

   --      The insertion character * is treated exactly like % except that the

   --      resulting name is cased according to the default conventions for

   --      reserved words (see package Scans).

   --    Insertion character & (Ampersand: insert name from node)

   --      The insertion character & is treated similarly to %, except that

   --      the name is taken from the Chars field of the given node, and may

   --      refer to a child unit name, or a selected component. The casing is,

   --      if possible, taken from the original source reference, which is

   --      obtained from the Sloc field of the given node or nodes. If no Sloc

   --      is available (happens e.g. for nodes in package Standard), then the

   --      default case (see Scans spec) is used. The nodes to be used are

   --      stored in Error_Msg_Node_1, Error_Msg_Node_2. No insertion occurs

   --      for the Empty node, and the Error node results in the insertion of

   --      the characters <error>. In addition, if the special global variable

   --      Error_Msg_Qual_Level is non-zero, then the reference will include

   --      up to the given number of levels of qualification, using the scope

   --      chain.

   --    Insertion character # (Pound: insert line number reference)

   --      The character # is replaced by the string indicating the source

   --      position stored in Error_Msg_Sloc. There are three cases:

   --

   --        for package Standard:           in package Standard

   --        for locations in current file:  at line nnn:ccc

   --        for locations in other files:   at filename:nnn:ccc

   --

   --      By convention, the # insertion character is only used at the end of

   --      an error message, so the above strings only appear as the last

   --      characters of an error message. The only exceptions to this rule

   --      are that an RM reference may follow in the form (RM .....) and a

   --      right parenthesis may immediately follow the #. In the case of

   --      continued messages, # can only appear at the end of a group of

   --      continuation messsages, except that \\ messages which always start

   --      a new line end the sequence from the point of view of this rule.

   --      The idea is that for any use of -gnatj, it will still be the case

   --      that a location reference appears only at the end of a line.

   --    Insertion character } (Right brace: insert type reference)

   --      The character } is replaced by a string describing the type

   --      referenced by the entity whose Id is stored in Error_Msg_Node_1.

   --      the string gives the name or description of the type, and also

   --      where appropriate the location of its declaration. Special cases

   --      like "some integer type" are handled appropriately. Only one } is

   --      allowed in a message, since there is not enough room for two (the

   --      insertion can be quite long, including a file name) In addition, if

   --      the special global variable Error_Msg_Qual_Level is non-zero, then

   --      the reference will include up to the given number of levels of

   --      qualification, using the scope chain.

   --    Insertion character @ (At: insert column number reference)

   --      The character @ is replaced by null if the RM_Column_Check mode is

   --      off (False). If the switch is on (True), then @ is replaced by the

   --      text string " in column nnn" where nnn is the decimal

   --      representation of the column number stored in Error_Msg_Col plus

   --      one (the plus one is because the number is stored 0-origin and

   --      displayed 1-origin).

   --    Insertion character ^ (Carret: insert integer value)

   --      The character ^ is replaced by the decimal conversion of the Uint

   --      value stored in Error_Msg_Uint_1, with a possible leading minus.

   --      A second ^ may occur in the message, in which case it is replaced

   --      by the decimal conversion of the Uint value in Error_Msg_Uint_2.

   --    Insertion character > (Right bracket, run time name)

   --      The character > is replaced by a string of the form (name) if

   --      Targparm scanned out a Run_Time_Name (see package Targparm for

   --      details). The name is enclosed in parentheses and output in mixed

   --      case mode (upper case after any space in the name). If no run time

   --      name is defined, this insertion character has no effect.

   --    Insertion character ! (Exclamation: unconditional message)

   --      The character ! appearing as the last character of a message makes

   --      the message unconditional which means that it is output even if it

   --      would normally be suppressed. See section above for a description

   --      of the cases in which messages are normally suppressed. Note that

   --      in the case of warnings, the meaning is that the warning should not

   --      be removed in dead code (that's the only time that the use of !

   --      has any effect for a warning).

   --

   --      Note: the presence of ! is ignored in continuation messages (i.e.

   --      messages starting with the \ insertion character). The effect of the

   --      use of ! in a parent message automatically applies to all of its

   --      continuation messages (since we clearly don't want any case in which

   --      continuations are separated from the parent message. It is allowable

   --      to put ! in continuation messages, and the usual style is to include

   --      it, since it makes it clear that the continuation is part of an

   --      unconditional message.

   --    Insertion character !! (unconditional warning)

   --      Normally warning messages issued in other than the main unit are

   --      suppressed. If the message ends with !! then this suppression is

   --      avoided. This is currently used by the Compile_Time_Warning pragma

   --      to ensure the message for a with'ed unit is output, and for warnings

   --      on ineffective back-end inlining, which is detected in units that

   --      contain subprograms to be inlined in the main program.

   --    Insertion character ? (Question: warning message)

   --      The character ? appearing anywhere in a message makes the message

   --      warning instead of a normal error message, and the text of the

   --      message will be preceded by "warning:" in the normal case. The

   --      handling of warnings if further controlled by the Warning_Mode

   --      option (-w switch), see package Opt for further details, and also by

   --      the current setting from pragma Warnings. This pragma applies only

   --      to warnings issued from the semantic phase (not the parser), but

   --      currently all relevant warnings are posted by the semantic phase

   --      anyway. Messages starting with (style) are also treated as warning

   --      messages.

   --

   --      Note: when a warning message is output, the text of the message is

   --      preceded by "warning: " in the normal case. An exception to this

   --      rule occurs when the text of the message starts with "info: " in

   --      which case this string is not prepended. This allows callers to

   --      label certain warnings as informational messages, rather than as

   --      warning messages requiring some action.

   --

   --      Note: the presence of ? is ignored in continuation messages (i.e.

   --      messages starting with the \ insertion character). The warning

   --      status of continuations is determined only by the parent message

   --      which is being continued. It is allowable to put ? in continuation

   --      messages, and the usual style is to include it, since it makes it

   --      clear that the continuation is part of a warning message.

   --    Insertion character < (Less Than: conditional warning message)

   --      The character < appearing anywhere in a message is used for a

   --      conditional error message. If Error_Msg_Warn is True, then the

   --      effect is the same as ? described above. If Error_Msg_Warn is

   --      False, then there is no effect.

   --    Insertion character A-Z (Upper case letter: Ada reserved word)

   --      If two or more upper case letters appear in the message, they are

   --      taken as an Ada reserved word, and are converted to the default

   --      case for reserved words (see Scans package spec). Surrounding

   --      quotes are added unless manual quotation mode is currently set.

   --    Insertion character ` (Backquote: set manual quotation mode)

   --      The backquote character always appears in pairs. Each backquote of

   --      the pair is replaced by a double quote character. In addition, any

   --      reserved keywords, or name insertions between these backquotes are

   --      not surrounded by the usual automatic double quotes. See the

   --      section below on manual quotation mode for further details.

   --    Insertion character ' (Quote: literal character)

   --      Precedes a character which is placed literally into the message.

   --      Used to insert characters into messages that are one of the

   --      insertion characters defined here. Also useful in inserting

   --      sequences of upper case letters (e.g. RM) which are not to be

   --      treated as keywords.

   --    Insertion character \ (Backslash: continuation message)

   --      Indicates that the message is a continuation of a message

   --      previously posted. This is used to ensure that such groups of

   --      messages are treated as a unit. The \ character must be the first

   --      character of the message text.

   --    Insertion character \\ (Two backslashes, continuation with new line)

   --      This differs from \ only in -gnatjnn mode (Error_Message_Line_Length

   --      set non-zero). This sequence forces a new line to start even when

   --      continuations are being gathered into a single message.

   --    Insertion character | (Vertical bar: non-serious error)

   --      By default, error messages (other than warning messages) are

   --      considered to be fatal error messages which prevent expansion or

   --      generation of code in the presence of the -gnatQ switch. If the

   --      insertion character | appears, the message is considered to be

   --      non-serious, and does not cause Serious_Errors_Detected to be

   --      incremented (so expansion is not prevented by such a msg).

   --    Insertion character ~ (Tilde: insert string)

   --      Indicates that Error_Msg_String (1 .. Error_Msg_Strlen) is to be

   --      inserted to replace the ~ character. The string is inserted in the

   --      literal form it appears, without any action on special characters.

   ----------------------------------------

   -- Specialization of Messages for VMS --

   ----------------------------------------

   --  Some messages mention gcc-style switch names. When using an OpenVMS

   --  host, such switch names must be converted to their corresponding VMS

   --  qualifer. The following table controls this translation. In each case

   --  the original message must contain the string "-xxx switch", where xxx

   --  is the Gname? entry from below, and this string will be replaced by

   --  "/yyy qualifier", where yyy is the corresponding Vname? entry.

   Gname1 : aliased constant String := "fno-strict-aliasing";

   Vname1 : aliased constant String := "OPTIMIZE=NO_STRICT_ALIASING";

   Gname2 : aliased constant String := "gnatX";

   Vname2 : aliased constant String := "EXTENSIONS_ALLOWED";

   Gname3 : aliased constant String := "gnatW";

   Vname3 : aliased constant String := "WIDE_CHARACTER_ENCODING";

   Gname4 : aliased constant String := "gnatf";

   Vname4 : aliased constant String := "REPORT_ERRORS=FULL";

   Gname5 : aliased constant String := "gnat05";

   Vname5 : aliased constant String := "05";

   type Cstring_Ptr is access constant String;

   Gnames : array (Nat range <>) of Cstring_Ptr :=

              (Gname1'Access,

               Gname2'Access,

               Gname3'Access,

               Gname4'Access,

               Gname5'Access);

   Vnames : array (Nat range <>) of Cstring_Ptr :=

              (Vname1'Access,

               Vname2'Access,

               Vname3'Access,

               Vname4'Access,

               Vname5'Access);

   -----------------------------------------------------

   -- Global Values Used for Error Message Insertions --

   -----------------------------------------------------

   --  The following global variables are essentially additional parameters

   --  passed to the error message routine for insertion sequences described

   --  above. The reason these are passed globally is that the insertion

   --  mechanism is essentially an untyped one in which the appropriate

   --  variables are set depending on the specific insertion characters used.

   --  Note that is mandatory that the caller ensure that global variables

   --  are set before the Error_Msg call, otherwise the result is undefined.

   Error_Msg_Col : Column_Number renames Err_Vars.Error_Msg_Col;

   --  Column for @ insertion character in message

   Error_Msg_Uint_1 : Uint renames Err_Vars.Error_Msg_Uint_1;

   Error_Msg_Uint_2 : Uint renames Err_Vars.Error_Msg_Uint_2;

   --  Uint values for ^ insertion characters in message

   Error_Msg_Sloc : Source_Ptr renames Err_Vars.Error_Msg_Sloc;

   --  Source location for # insertion character in message

   Error_Msg_Name_1 : Name_Id renames Err_Vars.Error_Msg_Name_1;

   Error_Msg_Name_2 : Name_Id renames Err_Vars.Error_Msg_Name_2;

   Error_Msg_Name_3 : Name_Id renames Err_Vars.Error_Msg_Name_3;

   --  Name_Id values for % insertion characters in message

   Error_Msg_File_1 : File_Name_Type renames Err_Vars.Error_Msg_File_1;

   Error_Msg_File_2 : File_Name_Type renames Err_Vars.Error_Msg_File_2;

   Error_Msg_File_3 : File_Name_Type renames Err_Vars.Error_Msg_File_3;

   --  File_Name_Type values for { insertion characters in message

   Error_Msg_Unit_1 : Unit_Name_Type renames Err_Vars.Error_Msg_Unit_1;

   Error_Msg_Unit_2 : Unit_Name_Type renames Err_Vars.Error_Msg_Unit_2;

   --  Unit_Name_Type values for $ insertion characters in message

   Error_Msg_Node_1 : Node_Id renames Err_Vars.Error_Msg_Node_1;

   Error_Msg_Node_2 : Node_Id renames Err_Vars.Error_Msg_Node_2;

   --  Node_Id values for & insertion characters in message

   Error_Msg_Qual_Level : Int renames Err_Vars.Error_Msg_Qual_Level;

   --  Number of levels of qualification required for type name (see the

   --  description of the } insertion character. Note that this value does

   --  note get reset by any Error_Msg call, so the caller is responsible

   --  for resetting it.

   Error_Msg_Warn : Boolean renames Err_Vars.Error_Msg_Warn;

   --  Used if current message contains a < insertion character to indicate

   --  if the current message is a warning message.

   Error_Msg_String : String  renames Err_Vars.Error_Msg_String;

   Error_Msg_Strlen : Natural renames Err_Vars.Error_Msg_Strlen;

   --  Used if current message contains a ~ insertion character to indicate

   --  insertion of the string Error_Msg_String (1 .. Error_Msg_Strlen).

   -----------------------------------------------------

   -- Format of Messages and Manual Quotation Control --

   -----------------------------------------------------

   --  Messages are generally all in lower case, except for inserted names

   --  and appear in one of the following three forms:

   --    error: text

   --    warning: text

   --  The prefixes error and warning are supplied automatically (depending

   --  on the use of the ? insertion character), and the call to the error

   --  message routine supplies the text. The "error: " prefix is omitted

   --  in brief error message formats.

   --  Reserved Ada keywords in the message are in the default keyword case

   --  (determined from the given source program), surrounded by quotation

   --  marks. This is achieved by spelling the reserved word in upper case

   --  letters, which is recognized as a request for insertion of quotation

   --  marks by the error text processor. Thus for example:

   --    Error_Msg_AP ("IS expected");

   --  would result in the output of one of the following:

   --    error: "is" expected

   --    error: "IS" expected

   --    error: "Is" expected

   --  the choice between these being made by looking at the casing convention

   --  used for keywords (actually the first compilation unit keyword) in the

   --  source file.

   --  Note: a special exception is that RM is never treated as a keyword

   --  but instead is copied literally into the message, this avoids the

   --  need for writing 'R'M for all reference manual quotes.

   --  In the case of names, the default mode for the error text processor

   --  is to surround the name by quotation marks automatically. The case

   --  used for the identifier names is taken from the source program where

   --  possible, and otherwise is the default casing convention taken from

   --  the source file usage.

   --  In some cases, better control over the placement of quote marks is

   --  required. This is achieved using manual quotation mode. In this mode,

   --  one or more insertion sequences is surrounded by backquote characters.

   --  The backquote characters are output as double quote marks, and normal

   --  automatic insertion of quotes is suppressed between the double quotes.

   --  For example:

   --    Error_Msg_AP ("`END &;` expected");

   --  generates a message like

   --    error: "end Open_Scope;" expected

   --  where the node specifying the name Open_Scope has been stored in

   --  Error_Msg_Node_1 prior to the call. The great majority of error

   --  messages operates in normal quotation mode.

   --  Note: the normal automatic insertion of spaces before insertion

   --  sequences (such as those that come from & and %) is suppressed in

   --  manual quotation mode, so blanks, if needed as in the above example,

   --  must be explicitly present.

   ----------------------------

   -- Message ID Definitions --

   ----------------------------

   subtype Error_Msg_Id is Erroutc.Error_Msg_Id;

   function "=" (Left, Right : Error_Msg_Id) return Boolean

     renames Erroutc."=";

   --  A type used to represent specific error messages. Used by the clients

   --  of this package only in the context of the Get_Error_Id and

   --  Change_Error_Text subprograms.

   No_Error_Msg : constant Error_Msg_Id := Erroutc.No_Error_Msg;

   --  A constant which is different from any value returned by Get_Error_Id.

   --  Typically used by a client to indicate absense of a saved Id value.

   function Get_Msg_Id return Error_Msg_Id renames Erroutc.Get_Msg_Id;

   --  Returns the Id of the message most recently posted using one of the

   --  Error_Msg routines.

   function Get_Location (E : Error_Msg_Id) return Source_Ptr

     renames Erroutc.Get_Location;

   --  Returns the flag location of the error message with the given id E

   ------------------------

   -- List Pragmas Table --

   ------------------------

   --  When a pragma Page or pragma List is encountered by the parser, an

   --  entry is made in the following table. This table is then used to

   --  control the full listing if one is being generated. Note that the

   --  reason we do the processing in the parser is so that we get proper

   --  listing control even in syntax check only mode.

   type List_Pragma_Type is (List_On, List_Off, Page);

   type List_Pragma_Record is record

      Ptyp : List_Pragma_Type;

      Ploc : Source_Ptr;

   end record;

   --  Note: Ploc points to the terminating semicolon in the List_Off and Page

   --  cases, and to the pragma keyword for List_On. In the case of a pragma

   --  List_Off, a List_On entry is also made in the table, pointing to the

   --  pragma keyword. This ensures that, as required, a List (Off) pragma is

   --  listed even in list off mode.

   package List_Pragmas is new Table.Table (

     Table_Component_Type => List_Pragma_Record,

     Table_Index_Type     => Int,

     Table_Low_Bound      => 1,

     Table_Initial        => 50,

     Table_Increment      => 200,

     Table_Name           => "List_Pragmas");

   ---------------------------

   -- Ignore_Errors Feature --

   ---------------------------

   --  In certain cases, notably for optional subunits, the compiler operates

   --  in a mode where errors are to be ignored, and the whole unit is to be

   --  considered as not present. To implement this we provide the following

   --  flag to enable special handling, where error messages are suppressed,

   --  but the Fatal_Error flag will still be set in the normal manner.

   Ignore_Errors_Enable : Nat := 0;

   --  Triggering switch. If non-zero, then ignore errors mode is activated.

   --  This is a counter to allow convenient nesting of enable/disable.

   -----------------------

   --  CODEFIX Facility --

   -----------------------

   --  The GPS and GNATBench IDE's have a codefix facility that allows for

   --  automatic correction of a subset of the errors and warnings issued

   --  by the compiler. This is done by recognizing the text of specific

   --  messages using appropriate matching patterns.

   --  The text of such messages should not be altered without coordinating

   --  with the codefix code. All such messages are marked by a specific

   --  style of comments, as shown by the following example:

   --     Error_Msg_N -- CODEFIX

   --       (parameters ....)

   --  Any message marked with this -- CODEFIX comment should not be modified

   --  without appropriate coordination. If new messages are added which may

   --  be susceptible to automatic codefix action, they are marked using:

   --     Error_Msg -- CODEFIX???

   --       (parameters)

   --  And subsequently either the appropriate code is added to codefix and the

   --  ??? are removed, or it is determined that this is not an appropriate

   --  case for codefix action, and the comment is removed.

   ------------------------------

   -- Error Output Subprograms --

   ------------------------------

   procedure Initialize;

   --  Initializes for output of error messages. Must be called for each

   --  source file before using any of the other routines in the package.

   procedure Finalize (Last_Call : Boolean);

   --  Finalize processing of error message list. Includes processing for

   --  duplicated error messages, and other similar final adjustment of the

   --  list of error messages. Note that this procedure must be called before

   --  calling Compilation_Errors to determine if there were any errors. It

   --  is perfectly fine to call Finalize more than once, providing that the

   --  parameter Last_Call is set False for every call except the last call.

   --  This multiple call capability is used to do some processing that may

   --  generate messages. Call Finalize to eliminate duplicates and remove

   --  deleted warnings. Test for compilation errors using Compilation_Errors,

   --  then generate some more errors/warnings, call Finalize again to make

   --  sure that all duplicates in these new messages are dealt with, then

   --  finally call Output_Messages to output the final list of messages. The

   --  argument Last_Call must be set False on all calls except the last call,

   --  and must be set True on the last call (a value of True activates some

   --  processing that must only be done after all messages are posted).

   procedure Output_Messages;

   --  Output list of messages, including messages giving number of detected

   --  errors and warnings.

   procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);

   --  Output a message at specified location. Can be called from the parser

   --  or the semantic analyzer.

   procedure Error_Msg_S (Msg : String);

   --  Output a message at current scan pointer location. This routine can be

   --  called only from the parser, since it references Scan_Ptr.

   procedure Error_Msg_AP (Msg : String);

   --  Output a message just after the previous token. This routine can be

   --  called only from the parser, since it references Prev_Token_Ptr.

   procedure Error_Msg_BC (Msg : String);

   --  Output a message just before the current token. Note that the important

   --  difference between this and the previous routine is that the BC case

   --  posts a flag on the current line, whereas AP can post a flag at the

   --  end of the preceding line. This routine can be called only from the

   --  parser, since it references Token_Ptr.

   procedure Error_Msg_SC (Msg : String);

   --  Output a message at the start of the current token, unless we are at

   --  the end of file, in which case we always output the message after the

   --  last real token in the file. This routine can be called only from the

   --  parser, since it references Token_Ptr.

   procedure Error_Msg_SP (Msg : String);

   --  Output a message at the start of the previous token. This routine can

   --  be called only from the parser, since it references Prev_Token_Ptr.

   procedure Error_Msg_N (Msg : String; N : Node_Or_Entity_Id);

   --  Output a message at the Sloc of the given node. This routine can be

   --  called from the parser or the semantic analyzer, although the call from

   --  the latter is much more common (and is the most usual way of generating

   --  error messages from the analyzer). The message text may contain a

   --  single & insertion, which will reference the given node. The message is

   --  suppressed if the node N already has a message posted, or if it is a

   --  warning and warnings and N is an entity node for which warnings are

   --  suppressed.

   procedure Error_Msg_F (Msg : String; N : Node_Id);

   --  Similar to Error_Msg_N except that the message is placed on the first

   --  node of the construct N (First_Node (N)).

   procedure Error_Msg_NE

     (Msg : String;

      N   : Node_Or_Entity_Id;

      E   : Node_Or_Entity_Id);

   --  Output a message at the Sloc of the given node N, with an insertion of

   --  the name from the given entity node E. This is used by the semantic

   --  routines, where this is a common error message situation. The Msg text

   --  will contain a & or } as usual to mark the insertion point. This

   --  routine can be called from the parser or the analyzer.

   procedure Error_Msg_FE

     (Msg : String;

      N   : Node_Id;

      E   : Node_Or_Entity_Id);

   --  Same as Error_Msg_NE, except that the message is placed on the first

   --  node of the construct N (First_Node (N)).

   procedure Error_Msg_NEL

     (Msg           : String;

      N             : Node_Or_Entity_Id;

      E             : Node_Or_Entity_Id;

      Flag_Location : Source_Ptr);

   --  Exactly the same as Error_Msg_NE, except that the flag is placed at

   --  the specified Flag_Location instead of at Sloc (N).

   procedure Error_Msg_NW

     (Eflag : Boolean;

      Msg   : String;

      N     : Node_Or_Entity_Id);

   --  This routine is used for posting a message conditionally. The message

   --  is posted (with the same effect as Error_Msg_N (Msg, N) if and only

   --  if Eflag is True and if the node N is within the main extended source

   --  unit and comes from source. Typically this is a warning mode flag.

   --  This routine can only be called during semantic analysis. It may not

   --  be called during parsing.

   procedure Change_Error_Text (Error_Id : Error_Msg_Id; New_Msg : String);

   --  The error message text of the message identified by Id is replaced by

   --  the given text. This text may contain insertion characters in the

   --  usual manner, and need not be the same length as the original text.

   function First_Node (C : Node_Id) return Node_Id;

   --  Given a construct C, finds the first node in the construct, i.e. the

   --  one with the lowest Sloc value. This is useful in placing error msgs.

   function First_Sloc (N : Node_Id) return Source_Ptr;

   --  Given the node for an expression, return a source pointer value that

   --  points to the start of the first token in the expression. In the case

   --  where the expression is parenthesized, an attempt is made to include

   --  the parentheses (i.e. to return the location of the initial paren).

   procedure Purge_Messages (From : Source_Ptr; To : Source_Ptr)

     renames Erroutc.Purge_Messages;

   --  All error messages whose location is in the range From .. To (not

   --  including the end points) will be deleted from the error listing.

   procedure Remove_Warning_Messages (N : Node_Id);

   --  Remove any warning messages corresponding to the Sloc of N or any

   --  of its descendent nodes. No effect if no such warnings. Note that

   --  style messages (identified by the fact that they start with "(style)"

   --  are not removed by this call. Basically the idea behind this procedure

   --  is to remove warnings about execution conditions from known dead code.

   procedure Remove_Warning_Messages (L : List_Id);

   --  Remove warnings on all elements of a list (Calls Remove_Warning_Messages

   --  on each element of the list, see above).

   procedure Set_Ignore_Errors (To : Boolean);

   --  Following a call to this procedure with To=True, all error calls are

   --  ignored. A call with To=False restores the default treatment in which

   --  error calls are treated as usual (and as described in this spec).

   procedure Set_Warnings_Mode_Off (Loc : Source_Ptr)

     renames Erroutc.Set_Warnings_Mode_Off;

   --  Called in response to a pragma Warnings (Off) to record the source

   --  location from which warnings are to be turned off.

   procedure Set_Warnings_Mode_On (Loc : Source_Ptr)

     renames Erroutc.Set_Warnings_Mode_On;

   --  Called in response to a pragma Warnings (On) to record the source

   --  location from which warnings are to be turned back on.

   procedure Set_Specific_Warning_Off

     (Loc    : Source_Ptr;

      Msg    : String;

      Config : Boolean)

     renames Erroutc.Set_Specific_Warning_Off;

   --  This is called in response to the two argument form of pragma Warnings

   --  where the first argument is OFF, and the second argument is the prefix

   --  of a specific warning to be suppressed. The first argument is the start

   --  of the suppression range, and the second argument is the string from

   --  the pragma.

   procedure Set_Specific_Warning_On

     (Loc : Source_Ptr;

      Msg : String;

      Err : out Boolean)

     renames Erroutc.Set_Specific_Warning_On;

   --  This is called in response to the two argument form of pragma Warnings

   --  where the first argument is ON, and the second argument is the prefix

   --  of a specific warning to be suppressed. The first argument is the end

   --  of the suppression range, and the second argument is the string from

   --  the pragma. Err is set to True on return to report the error of no

   --  matching Warnings Off pragma preceding this one.

   function Compilation_Errors return Boolean;

   --  Returns true if errors have been detected, or warnings in -gnatwe

   --  (treat warnings as errors) mode. Note that it is mandatory to call

   --  Finalize before calling this routine.

   procedure Error_Msg_CRT (Feature : String; N : Node_Id);

   --  Posts a non-fatal message on node N saying that the feature identified

   --  by the Feature argument is not supported in either configurable

   --  run-time mode or no run-time mode (as appropriate). In the former case,

   --  the name of the library is output if available.

   procedure dmsg (Id : Error_Msg_Id) renames Erroutc.dmsg;

   --  Debugging routine to dump an error message

   ------------------------------------

   -- Utility Interface for Back End --

   ------------------------------------

   --  The following subprograms can be used by the back end for the purposes

   --  of concocting error messages that are not output via Errout, e.g. the

   --  messages generated by the gcc back end.

   procedure Set_Identifier_Casing

     (Identifier_Name : System.Address;

      File_Name       : System.Address);

   --  The identifier is a null terminated string that represents the name of

   --  an identifier appearing in the source program. File_Name is a null

   --  terminated string giving the corresponding file name for the identifier

   --  as obtained from the front end by the use of Full_Debug_Name to the

   --  source file referenced by the corresponding source location value. On

   --  return, the name is in Name_Buffer, null terminated with Name_Len set.

   --  This name is the identifier name as passed, cased according to the

   --  default identifier casing for the given file.