path: root/gcc/ada/par-prag.adb

------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             P A R . P R A G                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2016, 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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  Generally the parser checks the basic syntax of pragmas, but does not
--  do specialized syntax checks for individual pragmas, these are deferred
--  to semantic analysis time (see unit Sem_Prag). There are some pragmas
--  which require recognition and either partial or complete processing
--  during parsing, and this unit performs this required processing.

with Fname.UF; use Fname.UF;
with Osint;    use Osint;
with Rident;   use Rident;
with Restrict; use Restrict;
with Stringt;  use Stringt;
with Stylesw;  use Stylesw;
with Uintp;    use Uintp;
with Uname;    use Uname;

with System.WCh_Con; use System.WCh_Con;

separate (Par)

function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id is
   Prag_Name   : constant Name_Id    := Pragma_Name_Unmapped (Pragma_Node);
   Prag_Id     : constant Pragma_Id  := Get_Pragma_Id (Prag_Name);
   Pragma_Sloc : constant Source_Ptr := Sloc (Pragma_Node);
   Arg_Count   : Nat;
   Arg_Node    : Node_Id;

   -----------------------
   -- Local Subprograms --
   -----------------------

   procedure Add_List_Pragma_Entry (PT : List_Pragma_Type; Loc : Source_Ptr);
   --  Make a new entry in the List_Pragmas table if this entry is not already
   --  in the table (it will always be the last one if there is a duplication
   --  resulting from the use of Save/Restore_Scan_State).

   function Arg1 return Node_Id;
   function Arg2 return Node_Id;
   function Arg3 return Node_Id;
   --  Obtain specified Pragma_Argument_Association. It is allowable to call
   --  the routine for the argument one past the last present argument, but
   --  that is the only case in which a non-present argument can be referenced.

   procedure Check_Arg_Count (Required : Int);
   --  Check argument count for pragma = Required. If not give error and raise
   --  Error_Resync.

   procedure Check_Arg_Is_String_Literal (Arg : Node_Id);
   --  Check the expression of the specified argument to make sure that it
   --  is a string literal. If not give error and raise Error_Resync.

   procedure Check_Arg_Is_On_Or_Off (Arg : Node_Id);
   --  Check the expression of the specified argument to make sure that it
   --  is an identifier which is either ON or OFF, and if not, then issue
   --  an error message and raise Error_Resync.

   procedure Check_No_Identifier (Arg : Node_Id);
   --  Checks that the given argument does not have an identifier. If
   --  an identifier is present, then an error message is issued, and
   --  Error_Resync is raised.

   procedure Check_Optional_Identifier (Arg : Node_Id; Id : Name_Id);
   --  Checks if the given argument has an identifier, and if so, requires
   --  it to match the given identifier name. If there is a non-matching
   --  identifier, then an error message is given and Error_Resync raised.

   procedure Check_Required_Identifier (Arg : Node_Id; Id : Name_Id);
   --  Same as Check_Optional_Identifier, except that the name is required
   --  to be present and to match the given Id value.

   procedure Process_Restrictions_Or_Restriction_Warnings;
   --  Common processing for Restrictions and Restriction_Warnings pragmas.
   --  For the most part, restrictions need not be processed at parse time,
   --  since they only affect semantic processing. This routine handles the
   --  exceptions as follows
   --
   --    No_Obsolescent_Features must be processed at parse time, since there
   --    are some obsolescent features (e.g. character replacements) which are
   --    handled at parse time.
   --
   --    SPARK must be processed at parse time, since this restriction controls
   --    whether the scanner recognizes a spark HIDE directive formatted as an
   --    Ada comment (and generates a Tok_SPARK_Hide token for the directive).
   --
   --    No_Dependence must be processed at parse time, since otherwise it gets
   --    handled too late.
   --
   --  Note that we don't need to do full error checking for badly formed cases
   --  of restrictions, since these will be caught during semantic analysis.

   ---------------------------
   -- Add_List_Pragma_Entry --
   ---------------------------

   procedure Add_List_Pragma_Entry (PT : List_Pragma_Type; Loc : Source_Ptr) is
   begin
      if List_Pragmas.Last < List_Pragmas.First
        or else (List_Pragmas.Table (List_Pragmas.Last)) /= ((PT, Loc))
      then
         List_Pragmas.Append ((PT, Loc));
      end if;
   end Add_List_Pragma_Entry;

   ----------
   -- Arg1 --
   ----------

   function Arg1 return Node_Id is
   begin
      return First (Pragma_Argument_Associations (Pragma_Node));
   end Arg1;

   ----------
   -- Arg2 --
   ----------

   function Arg2 return Node_Id is
   begin
      return Next (Arg1);
   end Arg2;

   ----------
   -- Arg3 --
   ----------

   function Arg3 return Node_Id is
   begin
      return Next (Arg2);
   end Arg3;

   ---------------------
   -- Check_Arg_Count --
   ---------------------

   procedure Check_Arg_Count (Required : Int) is
   begin
      if Arg_Count /= Required then
         Error_Msg ("wrong number of arguments for pragma%", Pragma_Sloc);
         raise Error_Resync;
      end if;
   end Check_Arg_Count;

   ----------------------------
   -- Check_Arg_Is_On_Or_Off --
   ----------------------------

   procedure Check_Arg_Is_On_Or_Off (Arg : Node_Id) is
      Argx : constant Node_Id := Expression (Arg);

   begin
      if Nkind (Expression (Arg)) /= N_Identifier
        or else not Nam_In (Chars (Argx), Name_On, Name_Off)
      then
         Error_Msg_Name_2 := Name_On;
         Error_Msg_Name_3 := Name_Off;

         Error_Msg ("argument for pragma% must be% or%", Sloc (Argx));
         raise Error_Resync;
      end if;
   end Check_Arg_Is_On_Or_Off;

   ---------------------------------
   -- Check_Arg_Is_String_Literal --
   ---------------------------------

   procedure Check_Arg_Is_String_Literal (Arg : Node_Id) is
   begin
      if Nkind (Expression (Arg)) /= N_String_Literal then
         Error_Msg
           ("argument for pragma% must be string literal",
             Sloc (Expression (Arg)));
         raise Error_Resync;
      end if;
   end Check_Arg_Is_String_Literal;

   -------------------------
   -- Check_No_Identifier --
   -------------------------

   procedure Check_No_Identifier (Arg : Node_Id) is
   begin
      if Chars (Arg) /= No_Name then
         Error_Msg_N ("pragma% does not permit named arguments", Arg);
         raise Error_Resync;
      end if;
   end Check_No_Identifier;

   -------------------------------
   -- Check_Optional_Identifier --
   -------------------------------

   procedure Check_Optional_Identifier (Arg : Node_Id; Id : Name_Id) is
   begin
      if Present (Arg) and then Chars (Arg) /= No_Name then
         if Chars (Arg) /= Id then
            Error_Msg_Name_2 := Id;
            Error_Msg_N ("pragma% argument expects identifier%", Arg);
         end if;
      end if;
   end Check_Optional_Identifier;

   -------------------------------
   -- Check_Required_Identifier --
   -------------------------------

   procedure Check_Required_Identifier (Arg : Node_Id; Id : Name_Id) is
   begin
      if Chars (Arg) /= Id then
         Error_Msg_Name_2 := Id;
         Error_Msg_N ("pragma% argument must have identifier%", Arg);
      end if;
   end Check_Required_Identifier;

   --------------------------------------------------
   -- Process_Restrictions_Or_Restriction_Warnings --
   --------------------------------------------------

   procedure Process_Restrictions_Or_Restriction_Warnings is
      Arg  : Node_Id;
      Id   : Name_Id;
      Expr : Node_Id;

   begin
      Arg := Arg1;
      while Present (Arg) loop
         Id := Chars (Arg);
         Expr := Expression (Arg);

         if Id = No_Name and then Nkind (Expr) = N_Identifier then
            case Chars (Expr) is
               when Name_No_Obsolescent_Features =>
                  Set_Restriction (No_Obsolescent_Features, Pragma_Node);
                  Restriction_Warnings (No_Obsolescent_Features) :=
                    Prag_Id = Pragma_Restriction_Warnings;

               when Name_SPARK
                  | Name_SPARK_05
               =>
                  Set_Restriction (SPARK_05, Pragma_Node);
                  Restriction_Warnings (SPARK_05) :=
                    Prag_Id = Pragma_Restriction_Warnings;

               when others =>
                  null;
            end case;

         elsif Id = Name_No_Dependence then
            Set_Restriction_No_Dependence
              (Unit => Expr,
               Warn => Prag_Id = Pragma_Restriction_Warnings
                         or else Treat_Restrictions_As_Warnings);
         end if;

         Next (Arg);
      end loop;
   end Process_Restrictions_Or_Restriction_Warnings;

--  Start of processing for Prag

begin
   Error_Msg_Name_1 := Prag_Name;

   --  Ignore unrecognized pragma. We let Sem post the warning for this, since
   --  it is a semantic error, not a syntactic one (we have already checked
   --  the syntax for the unrecognized pragma as required by (RM 2.8(11)).

   if Prag_Id = Unknown_Pragma then
      return Pragma_Node;
   end if;

   --  Ignore pragma previously flagged by Ignore_Pragma

   if Get_Name_Table_Boolean3 (Prag_Name) then
      return Pragma_Node;
   end if;

   --  Count number of arguments. This loop also checks if any of the arguments
   --  are Error, indicating a syntax error as they were parsed. If so, we
   --  simply return, because we get into trouble with cascaded errors if we
   --  try to perform our error checks on junk arguments.

   Arg_Count := 0;

   if Present (Pragma_Argument_Associations (Pragma_Node)) then
      Arg_Node := Arg1;
      while Arg_Node /= Empty loop
         Arg_Count := Arg_Count + 1;

         if Expression (Arg_Node) = Error then
            return Error;
         end if;

         Next (Arg_Node);
      end loop;
   end if;

   --  Remaining processing is pragma dependent

   case Prag_Id is

      ------------
      -- Ada_83 --
      ------------

      --  This pragma must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax.

      when Pragma_Ada_83 =>
         if not Latest_Ada_Only then
            Ada_Version := Ada_83;
            Ada_Version_Explicit := Ada_83;
            Ada_Version_Pragma := Pragma_Node;
         end if;

      ------------
      -- Ada_95 --
      ------------

      --  This pragma must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax.

      when Pragma_Ada_95 =>
         if not Latest_Ada_Only then
            Ada_Version := Ada_95;
            Ada_Version_Explicit := Ada_95;
            Ada_Version_Pragma := Pragma_Node;
         end if;

      ---------------------
      -- Ada_05/Ada_2005 --
      ---------------------

      --  These pragmas must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax. However, it is only the zero argument form that
      --  must be processed at parse time.

      when Pragma_Ada_05
         | Pragma_Ada_2005
      =>
         if Arg_Count = 0 and not Latest_Ada_Only then
            Ada_Version := Ada_2005;
            Ada_Version_Explicit := Ada_2005;
            Ada_Version_Pragma := Pragma_Node;
         end if;

      ---------------------
      -- Ada_12/Ada_2012 --
      ---------------------

      --  These pragmas must be processed at parse time, since we want to set
      --  the Ada version properly at parse time to recognize the appropriate
      --  Ada version syntax. However, it is only the zero argument form that
      --  must be processed at parse time.

      when Pragma_Ada_12
         | Pragma_Ada_2012
      =>
         if Arg_Count = 0 then
            Ada_Version := Ada_2012;
            Ada_Version_Explicit := Ada_2012;
            Ada_Version_Pragma := Pragma_Node;
         end if;

      ---------------------------
      -- Compiler_Unit_Warning --
      ---------------------------

      --  This pragma must be processed at parse time, since the resulting
      --  status may be tested during the parsing of the program.

      when Pragma_Compiler_Unit
         | Pragma_Compiler_Unit_Warning
      =>
         Check_Arg_Count (0);

         --  Only recognized in main unit

         if Current_Source_Unit = Main_Unit then
            Compiler_Unit := True;
         end if;

      -----------
      -- Debug --
      -----------

      --  pragma Debug ([boolean_EXPRESSION,] PROCEDURE_CALL_STATEMENT);

      when Pragma_Debug =>
         Check_No_Identifier (Arg1);

         if Arg_Count = 2 then
            Check_No_Identifier (Arg2);
         else
            Check_Arg_Count (1);
         end if;

      -------------------------------
      -- Extensions_Allowed (GNAT) --
      -------------------------------

      --  pragma Extensions_Allowed (Off | On)

      --  The processing for pragma Extensions_Allowed must be done at
      --  parse time, since extensions mode may affect what is accepted.

      when Pragma_Extensions_Allowed =>
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         Check_Arg_Is_On_Or_Off (Arg1);

         if Chars (Expression (Arg1)) = Name_On then
            Extensions_Allowed := True;
            Ada_Version := Ada_2012;
         else
            Extensions_Allowed := False;
            Ada_Version := Ada_Version_Explicit;
         end if;

      -------------------
      -- Ignore_Pragma --
      -------------------

      --  Processing for this pragma must be done at parse time, since we want
      --  be able to ignore pragmas that are otherwise processed at parse time.

      when Pragma_Ignore_Pragma => Ignore_Pragma : declare
         A : Node_Id;

      begin
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         A := Expression (Arg1);

         if Nkind (A) /= N_Identifier then
            Error_Msg ("incorrect argument for pragma %", Sloc (A));
         else
            Set_Name_Table_Boolean3 (Chars (A), True);
         end if;
      end Ignore_Pragma;

      ----------------
      -- List (2.8) --
      ----------------

      --  pragma List (Off | On)

      --  The processing for pragma List must be done at parse time, since a
      --  listing can be generated in parse only mode.

      when Pragma_List =>
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         Check_Arg_Is_On_Or_Off (Arg1);

         --  We unconditionally make a List_On entry for the pragma, so that
         --  in the List (Off) case, the pragma will print even in a region
         --  of code with listing turned off (this is required).

         Add_List_Pragma_Entry (List_On, Sloc (Pragma_Node));

         --  Now generate the list off entry for pragma List (Off)

         if Chars (Expression (Arg1)) = Name_Off then
            Add_List_Pragma_Entry (List_Off, Semi);
         end if;

      ----------------
      -- Page (2.8) --
      ----------------

      --  pragma Page;

      --  Processing for this pragma must be done at parse time, since a
      --  listing can be generated in parse only mode with semantics off.

      when Pragma_Page =>
         Check_Arg_Count (0);
         Add_List_Pragma_Entry (Page, Semi);

      ------------------
      -- Restrictions --
      ------------------

      --  pragma Restrictions (RESTRICTION {, RESTRICTION});

      --  RESTRICTION ::=
      --    restriction_IDENTIFIER
      --  | restriction_parameter_IDENTIFIER => EXPRESSION

      --  We process the case of No_Obsolescent_Features, since this has
      --  a syntactic effect that we need to detect at parse time (the use
      --  of replacement characters such as colon for pound sign).

      when Pragma_Restrictions =>
         Process_Restrictions_Or_Restriction_Warnings;

      --------------------------
      -- Restriction_Warnings --
      --------------------------

      --  pragma Restriction_Warnings (RESTRICTION {, RESTRICTION});

      --  RESTRICTION ::=
      --    restriction_IDENTIFIER
      --  | restriction_parameter_IDENTIFIER => EXPRESSION

      --  See above comment for pragma Restrictions

      when Pragma_Restriction_Warnings =>
         Process_Restrictions_Or_Restriction_Warnings;

      ----------------------------------------------------------
      -- Source_File_Name and Source_File_Name_Project (GNAT) --
      ----------------------------------------------------------

      --  These two pragmas have the same syntax and semantics.
      --  There are five forms of these pragmas:

      --  pragma Source_File_Name[_Project] (
      --    [UNIT_NAME      =>] unit_NAME,
      --     BODY_FILE_NAME =>  STRING_LITERAL
      --    [, [INDEX =>] INTEGER_LITERAL]);

      --  pragma Source_File_Name[_Project] (
      --    [UNIT_NAME      =>] unit_NAME,
      --     SPEC_FILE_NAME =>  STRING_LITERAL
      --    [, [INDEX =>] INTEGER_LITERAL]);

      --  pragma Source_File_Name[_Project] (
      --     BODY_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT => STRING_LITERAL]
      --  [, CASING          => CASING_SPEC]);

      --  pragma Source_File_Name[_Project] (
      --     SPEC_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT => STRING_LITERAL]
      --  [, CASING          => CASING_SPEC]);

      --  pragma Source_File_Name[_Project] (
      --     SUBUNIT_FILE_NAME  => STRING_LITERAL
      --  [, DOT_REPLACEMENT    => STRING_LITERAL]
      --  [, CASING             => CASING_SPEC]);

      --  CASING_SPEC ::= Uppercase | Lowercase | Mixedcase

      --  Pragma Source_File_Name_Project (SFNP) is equivalent to pragma
      --  Source_File_Name (SFN), however their usage is exclusive:
      --  SFN can only be used when no project file is used, while
      --  SFNP can only be used when a project file is used.

      --  The Project Manager produces a configuration pragmas file that
      --  is communicated to the compiler with -gnatec switch. This file
      --  contains only SFNP pragmas (at least two for the default naming
      --  scheme. As this configuration pragmas file is always the first
      --  processed by the compiler, it prevents the use of pragmas SFN in
      --  other config files when a project file is in use.

      --  Note: we process this during parsing, since we need to have the
      --  source file names set well before the semantic analysis starts,
      --  since we load the spec and with'ed packages before analysis.

      when Pragma_Source_File_Name
         | Pragma_Source_File_Name_Project
      =>
         Source_File_Name : declare
            Unam  : Unit_Name_Type;
            Expr1 : Node_Id;
            Pat   : String_Ptr;
            Typ   : Character;
            Dot   : String_Ptr;
            Cas   : Casing_Type;
            Nast  : Nat;
            Expr  : Node_Id;
            Index : Nat;

            function Get_Fname (Arg : Node_Id) return File_Name_Type;
            --  Process file name from unit name form of pragma

            function Get_String_Argument (Arg : Node_Id) return String_Ptr;
            --  Process string literal value from argument

            procedure Process_Casing (Arg : Node_Id);
            --  Process Casing argument of pattern form of pragma

            procedure Process_Dot_Replacement (Arg : Node_Id);
            --  Process Dot_Replacement argument of pattern form of pragma

            ---------------
            -- Get_Fname --
            ---------------

            function Get_Fname (Arg : Node_Id) return File_Name_Type is
            begin
               String_To_Name_Buffer (Strval (Expression (Arg)));

               for J in 1 .. Name_Len loop
                  if Is_Directory_Separator (Name_Buffer (J)) then
                     Error_Msg
                       ("directory separator character not allowed",
                        Sloc (Expression (Arg)) + Source_Ptr (J));
                  end if;
               end loop;

               return Name_Find;
            end Get_Fname;

            -------------------------
            -- Get_String_Argument --
            -------------------------

            function Get_String_Argument (Arg : Node_Id) return String_Ptr is
               Str : String_Id;

            begin
               if Nkind (Expression (Arg)) /= N_String_Literal
                 and then
                  Nkind (Expression (Arg)) /= N_Operator_Symbol
               then
                  Error_Msg_N
                    ("argument for pragma% must be string literal", Arg);
                  raise Error_Resync;
               end if;

               Str := Strval (Expression (Arg));

               --  Check string has no wide chars

               for J in 1 .. String_Length (Str) loop
                  if Get_String_Char (Str, J) > 255 then
                     Error_Msg
                       ("wide character not allowed in pattern for pragma%",
                        Sloc (Expression (Arg2)) + Text_Ptr (J) - 1);
                  end if;
               end loop;

               --  Acquire string

               String_To_Name_Buffer (Str);
               return new String'(Name_Buffer (1 .. Name_Len));
            end Get_String_Argument;

            --------------------
            -- Process_Casing --
            --------------------

            procedure Process_Casing (Arg : Node_Id) is
               Expr : constant Node_Id := Expression (Arg);

            begin
               Check_Required_Identifier (Arg, Name_Casing);

               if Nkind (Expr) = N_Identifier then
                  if Chars (Expr) = Name_Lowercase then
                     Cas := All_Lower_Case;
                     return;
                  elsif Chars (Expr) = Name_Uppercase then
                     Cas := All_Upper_Case;
                     return;
                  elsif Chars (Expr) = Name_Mixedcase then
                     Cas := Mixed_Case;
                     return;
                  end if;
               end if;

               Error_Msg_N
                 ("Casing argument for pragma% must be " &
                  "one of Mixedcase, Lowercase, Uppercase",
                  Arg);
            end Process_Casing;

            -----------------------------
            -- Process_Dot_Replacement --
            -----------------------------

            procedure Process_Dot_Replacement (Arg : Node_Id) is
            begin
               Check_Required_Identifier (Arg, Name_Dot_Replacement);
               Dot := Get_String_Argument (Arg);
            end Process_Dot_Replacement;

         --  Start of processing for Source_File_Name and
         --  Source_File_Name_Project pragmas.

         begin
            if Prag_Id = Pragma_Source_File_Name then
               if Project_File_In_Use = In_Use then
                  Error_Msg
                    ("pragma Source_File_Name cannot be used " &
                     "with a project file", Pragma_Sloc);

               else
                  Project_File_In_Use := Not_In_Use;
               end if;

            else
               if Project_File_In_Use = Not_In_Use then
                  Error_Msg
                    ("pragma Source_File_Name_Project should only be used " &
                     "with a project file", Pragma_Sloc);
               else
                  Project_File_In_Use := In_Use;
               end if;
            end if;

            --  We permit from 1 to 3 arguments

            if Arg_Count not in 1 .. 3 then
               Check_Arg_Count (1);
            end if;

            Expr1 := Expression (Arg1);

            --  If first argument is identifier or selected component, then
            --  we have the specific file case of the Source_File_Name pragma,
            --  and the first argument is a unit name.

            if Nkind (Expr1) = N_Identifier
              or else
                (Nkind (Expr1) = N_Selected_Component
                  and then
                 Nkind (Selector_Name (Expr1)) = N_Identifier)
            then
               if Nkind (Expr1) = N_Identifier
                 and then Chars (Expr1) = Name_System
               then
                  Error_Msg_N
                    ("pragma Source_File_Name may not be used for System",
                     Arg1);
                  return Error;
               end if;

               --  Process index argument if present

               if Arg_Count = 3 then
                  Expr := Expression (Arg3);

                  if Nkind (Expr) /= N_Integer_Literal
                    or else not UI_Is_In_Int_Range (Intval (Expr))
                    or else Intval (Expr) > 999
                    or else Intval (Expr) <= 0
                  then
                     Error_Msg
                       ("pragma% index must be integer literal" &
                        " in range 1 .. 999", Sloc (Expr));
                     raise Error_Resync;
                  else
                     Index := UI_To_Int (Intval (Expr));
                  end if;

               --  No index argument present

               else
                  Check_Arg_Count (2);
                  Index := 0;
               end if;

               Check_Optional_Identifier (Arg1, Name_Unit_Name);
               Unam := Get_Unit_Name (Expr1);

               Check_Arg_Is_String_Literal (Arg2);

               if Chars (Arg2) = Name_Spec_File_Name then
                  Set_File_Name
                    (Get_Spec_Name (Unam), Get_Fname (Arg2), Index);

               elsif Chars (Arg2) = Name_Body_File_Name then
                  Set_File_Name
                    (Unam, Get_Fname (Arg2), Index);

               else
                  Error_Msg_N
                    ("pragma% argument has incorrect identifier", Arg2);
                  return Pragma_Node;
               end if;

            --  If the first argument is not an identifier, then we must have
            --  the pattern form of the pragma, and the first argument must be
            --  the pattern string with an appropriate name.

            else
               if Chars (Arg1) = Name_Spec_File_Name then
                  Typ := 's';

               elsif Chars (Arg1) = Name_Body_File_Name then
                  Typ := 'b';

               elsif Chars (Arg1) = Name_Subunit_File_Name then
                  Typ := 'u';

               elsif Chars (Arg1) = Name_Unit_Name then
                  Error_Msg_N
                    ("Unit_Name parameter for pragma% must be an identifier",
                     Arg1);
                  raise Error_Resync;

               else
                  Error_Msg_N
                    ("pragma% argument has incorrect identifier", Arg1);
                  raise Error_Resync;
               end if;

               Pat := Get_String_Argument (Arg1);

               --  Check pattern has exactly one asterisk

               Nast := 0;
               for J in Pat'Range loop
                  if Pat (J) = '*' then
                     Nast := Nast + 1;
                  end if;
               end loop;

               if Nast /= 1 then
                  Error_Msg_N
                    ("file name pattern must have exactly one * character",
                     Arg1);
                  return Pragma_Node;
               end if;

               --  Set defaults for Casing and Dot_Separator parameters

               Cas := All_Lower_Case;
               Dot := new String'(".");

               --  Process second and third arguments if present

               if Arg_Count > 1 then
                  if Chars (Arg2) = Name_Casing then
                     Process_Casing (Arg2);

                     if Arg_Count = 3 then
                        Process_Dot_Replacement (Arg3);
                     end if;

                  else
                     Process_Dot_Replacement (Arg2);

                     if Arg_Count = 3 then
                        Process_Casing (Arg3);
                     end if;
                  end if;
               end if;

               Set_File_Name_Pattern (Pat, Typ, Dot, Cas);
            end if;
         end Source_File_Name;

      -----------------------------
      -- Source_Reference (GNAT) --
      -----------------------------

      --  pragma Source_Reference
      --    (INTEGER_LITERAL [, STRING_LITERAL] );

      --  Processing for this pragma must be done at parse time, since error
      --  messages needing the proper line numbers can be generated in parse
      --  only mode with semantic checking turned off, and indeed we usually
      --  turn off semantic checking anyway if any parse errors are found.

      when Pragma_Source_Reference => Source_Reference : declare
         Fname : File_Name_Type;

      begin
         if Arg_Count /= 1 then
            Check_Arg_Count (2);
            Check_No_Identifier (Arg2);
         end if;

         --  Check that this is first line of file. We skip this test if
         --  we are in syntax check only mode, since we may be dealing with
         --  multiple compilation units.

         if Get_Physical_Line_Number (Pragma_Sloc) /= 1
           and then Num_SRef_Pragmas (Current_Source_File) = 0
           and then Operating_Mode /= Check_Syntax
         then
            Error_Msg -- CODEFIX
              ("first % pragma must be first line of file", Pragma_Sloc);
            raise Error_Resync;
         end if;

         Check_No_Identifier (Arg1);

         if Arg_Count = 1 then
            if Num_SRef_Pragmas (Current_Source_File) = 0 then
               Error_Msg
                 ("file name required for first % pragma in file",
                  Pragma_Sloc);
               raise Error_Resync;
            else
               Fname := No_File;
            end if;

         --  File name present

         else
            Check_Arg_Is_String_Literal (Arg2);
            String_To_Name_Buffer (Strval (Expression (Arg2)));
            Fname := Name_Find;

            if Num_SRef_Pragmas (Current_Source_File) > 0 then
               if Fname /= Full_Ref_Name (Current_Source_File) then
                  Error_Msg
                    ("file name must be same in all % pragmas", Pragma_Sloc);
                  raise Error_Resync;
               end if;
            end if;
         end if;

         if Nkind (Expression (Arg1)) /= N_Integer_Literal then
            Error_Msg
              ("argument for pragma% must be integer literal",
                Sloc (Expression (Arg1)));
            raise Error_Resync;

         --  OK, this source reference pragma is effective, however, we
         --  ignore it if it is not in the first unit in the multiple unit
         --  case. This is because the only purpose in this case is to
         --  provide source pragmas for subsequent use by gnatchop.

         else
            if Num_Library_Units = 1 then
               Register_Source_Ref_Pragma
                 (Fname,
                  Strip_Directory (Fname),
                  UI_To_Int (Intval (Expression (Arg1))),
                  Get_Physical_Line_Number (Pragma_Sloc) + 1);
            end if;
         end if;
      end Source_Reference;

      -------------------------
      -- Style_Checks (GNAT) --
      -------------------------

      --  pragma Style_Checks (On | Off | ALL_CHECKS | STRING_LITERAL);

      --  This is processed by the parser since some of the style
      --  checks take place during source scanning and parsing.

      when Pragma_Style_Checks => Style_Checks : declare
         A  : Node_Id;
         S  : String_Id;
         C  : Char_Code;
         OK : Boolean := True;

      begin
         --  Two argument case is only for semantics

         if Arg_Count = 2 then
            null;

         else
            Check_Arg_Count (1);
            Check_No_Identifier (Arg1);
            A := Expression (Arg1);

            if Nkind (A) = N_String_Literal then
               S := Strval (A);

               declare
                  Slen    : constant Natural := Natural (String_Length (S));
                  Options : String (1 .. Slen);
                  J       : Positive;
                  Ptr     : Positive;

               begin
                  J := 1;
                  loop
                     C := Get_String_Char (S, Pos (J));

                     if not In_Character_Range (C) then
                        OK := False;
                        Ptr := J;
                        exit;

                     else
                        Options (J) := Get_Character (C);
                     end if;

                     if J = Slen then
                        if not Ignore_Style_Checks_Pragmas then
                           Set_Style_Check_Options (Options, OK, Ptr);
                        end if;

                        exit;

                     else
                        J := J + 1;
                     end if;
                  end loop;

                  if not OK then
                     Error_Msg
                       (Style_Msg_Buf (1 .. Style_Msg_Len),
                        Sloc (Expression (Arg1)) + Source_Ptr (Ptr));
                     raise Error_Resync;
                  end if;
               end;

            elsif Nkind (A) /= N_Identifier then
               OK := False;

            elsif Chars (A) = Name_All_Checks then
               if not Ignore_Style_Checks_Pragmas then
                  if GNAT_Mode then
                     Stylesw.Set_GNAT_Style_Check_Options;
                  else
                     Stylesw.Set_Default_Style_Check_Options;
                  end if;
               end if;

            elsif Chars (A) = Name_On then
               if not Ignore_Style_Checks_Pragmas then
                  Style_Check := True;
               end if;

            elsif Chars (A) = Name_Off then
               if not Ignore_Style_Checks_Pragmas then
                  Style_Check := False;
               end if;

            else
               OK := False;
            end if;

            if not OK then
               Error_Msg ("incorrect argument for pragma%", Sloc (A));
               raise Error_Resync;
            end if;
         end if;
      end Style_Checks;

      -------------------------
      -- Suppress_All (GNAT) --
      -------------------------

      --  pragma Suppress_All

      --  This is a rather odd pragma, because other compilers allow it in
      --  strange places. DEC allows it at the end of units, and Rational
      --  allows it as a program unit pragma, when it would be more natural
      --  if it were a configuration pragma.

      --  Since the reason we provide this pragma is for compatibility with
      --  these other compilers, we want to accommodate these strange placement
      --  rules, and the easiest thing is simply to allow it anywhere in a
      --  unit. If this pragma appears anywhere within a unit, then the effect
      --  is as though a pragma Suppress (All_Checks) had appeared as the first
      --  line of the current file, i.e. as the first configuration pragma in
      --  the current unit.

      --  To get this effect, we set the flag Has_Pragma_Suppress_All in the
      --  compilation unit node for the current source file then in the last
      --  stage of parsing a file, if this flag is set, we materialize the
      --  Suppress (All_Checks) pragma, marked as not coming from Source.

      when Pragma_Suppress_All =>
         Set_Has_Pragma_Suppress_All (Cunit (Current_Source_Unit));

      ---------------------
      -- Warnings (GNAT) --
      ---------------------

      --  pragma Warnings ([TOOL_NAME,] DETAILS [, REASON]);

      --  DETAILS ::= On | Off
      --  DETAILS ::= On | Off, local_NAME
      --  DETAILS ::= static_string_EXPRESSION
      --  DETAILS ::= On | Off, static_string_EXPRESSION

      --  TOOL_NAME ::= GNAT | GNATProve

      --  REASON ::= Reason => STRING_LITERAL {& STRING_LITERAL}

      --  Note: If the first argument matches an allowed tool name, it is
      --  always considered to be a tool name, even if there is a string
      --  variable of that name.

      --  The one argument ON/OFF case is processed by the parser, since it may
      --  control parser warnings as well as semantic warnings, and in any case
      --  we want to be absolutely sure that the range in the warnings table is
      --  set well before any semantic analysis is performed. Note that we
      --  ignore this pragma if debug flag -gnatd.i is set.

      --  Also note that the "one argument" case may have two or three
      --  arguments if the first one is a tool name, and/or the last one is a
      --  reason argument.

      when Pragma_Warnings => Warnings : declare
         function First_Arg_Is_Matching_Tool_Name return Boolean;
         --  Returns True if the first argument is a tool name matching the
         --  current tool being run.

         function Last_Arg return Node_Id;
         --  Returns the last argument

         function Last_Arg_Is_Reason return Boolean;
         --  Returns True if the last argument is a reason argument

         function Get_Reason return String_Id;
         --  Analyzes Reason argument and returns corresponding String_Id
         --  value, or null if there is no Reason argument, or if the
         --  argument is not of the required form.

         -------------------------------------
         -- First_Arg_Is_Matching_Tool_Name --
         -------------------------------------

         function First_Arg_Is_Matching_Tool_Name return Boolean is
         begin
            return Nkind (Arg1) = N_Identifier

              --  Return True if the tool name is GNAT, and we're not in
              --  GNATprove or CodePeer or ASIS mode...

              and then ((Chars (Arg1) = Name_Gnat
                          and then not
                            (CodePeer_Mode or GNATprove_Mode or ASIS_Mode))

              --  or if the tool name is GNATprove, and we're in GNATprove
              --  mode.

                        or else
                        (Chars (Arg1) = Name_Gnatprove
                          and then GNATprove_Mode));
         end First_Arg_Is_Matching_Tool_Name;

         ----------------
         -- Get_Reason --
         ----------------

         function Get_Reason return String_Id is
            Arg : constant Node_Id := Last_Arg;
         begin
            if Last_Arg_Is_Reason then
               Start_String;
               Get_Reason_String (Expression (Arg));
               return End_String;
            else
               return Null_String_Id;
            end if;
         end Get_Reason;

         --------------
         -- Last_Arg --
         --------------

         function Last_Arg return Node_Id is
               Last_Arg : Node_Id;

         begin
            if Arg_Count = 1 then
               Last_Arg := Arg1;
            elsif Arg_Count = 2 then
               Last_Arg := Arg2;
            elsif Arg_Count = 3 then
               Last_Arg := Arg3;
            elsif Arg_Count = 4 then
               Last_Arg := Next (Arg3);

            --  Illegal case, error issued in semantic analysis

            else
               Last_Arg := Empty;
            end if;

            return Last_Arg;
         end Last_Arg;

         ------------------------
         -- Last_Arg_Is_Reason --
         ------------------------

         function Last_Arg_Is_Reason return Boolean is
            Arg : constant Node_Id := Last_Arg;
         begin
            return Nkind (Arg) in N_Has_Chars
              and then Chars (Arg) = Name_Reason;
         end Last_Arg_Is_Reason;

         The_Arg : Node_Id;  --  On/Off argument
         Argx    : Node_Id;

      --  Start of processing for Warnings

      begin
         if not Debug_Flag_Dot_I
           and then (Arg_Count = 1
                       or else (Arg_Count = 2
                                  and then (First_Arg_Is_Matching_Tool_Name
                                              or else
                                            Last_Arg_Is_Reason))
                       or else (Arg_Count = 3
                                  and then First_Arg_Is_Matching_Tool_Name
                                  and then Last_Arg_Is_Reason))
         then
            if First_Arg_Is_Matching_Tool_Name then
               The_Arg := Arg2;
            else
               The_Arg := Arg1;
            end if;

            Check_No_Identifier (The_Arg);
            Argx := Expression (The_Arg);

            if Nkind (Argx) = N_Identifier then
               if Chars (Argx) = Name_On then
                  Set_Warnings_Mode_On (Pragma_Sloc);
               elsif Chars (Argx) = Name_Off then
                  Set_Warnings_Mode_Off (Pragma_Sloc, Get_Reason);
               end if;
            end if;
         end if;
      end Warnings;

      -----------------------------
      -- Wide_Character_Encoding --
      -----------------------------

      --  pragma Wide_Character_Encoding (IDENTIFIER | CHARACTER_LITERAL);

      --  This is processed by the parser, since the scanner is affected

      when Pragma_Wide_Character_Encoding => Wide_Character_Encoding : declare
         A : Node_Id;

      begin
         Check_Arg_Count (1);
         Check_No_Identifier (Arg1);
         A := Expression (Arg1);

         if Nkind (A) = N_Identifier then
            Get_Name_String (Chars (A));
            Wide_Character_Encoding_Method :=
              Get_WC_Encoding_Method (Name_Buffer (1 .. Name_Len));

         elsif Nkind (A) = N_Character_Literal then
            declare
               R : constant Char_Code :=
                     Char_Code (UI_To_Int (Char_Literal_Value (A)));
            begin
               if In_Character_Range (R) then
                  Wide_Character_Encoding_Method :=
                    Get_WC_Encoding_Method (Get_Character (R));
               else
                  raise Constraint_Error;
               end if;
            end;

         else
            raise Constraint_Error;
         end if;

         Upper_Half_Encoding :=
           Wide_Character_Encoding_Method in
             WC_Upper_Half_Encoding_Method;

      exception
         when Constraint_Error =>
            Error_Msg_N ("invalid argument for pragma%", Arg1);
      end Wide_Character_Encoding;

      -----------------------
      -- All Other Pragmas --
      -----------------------

      --  For all other pragmas, checking and processing is handled
      --  entirely in Sem_Prag, and no further checking is done by Par.

      when Pragma_Abort_Defer
         | Pragma_Abstract_State
         | Pragma_Async_Readers
         | Pragma_Async_Writers
         | Pragma_Assertion_Policy
         | Pragma_Assume
         | Pragma_Assume_No_Invalid_Values
         | Pragma_All_Calls_Remote
         | Pragma_Allow_Integer_Address
         | Pragma_Annotate
         | Pragma_Assert
         | Pragma_Assert_And_Cut
         | Pragma_Asynchronous
         | Pragma_Atomic
         | Pragma_Atomic_Components
         | Pragma_Attach_Handler
         | Pragma_Attribute_Definition
         | Pragma_Check
         | Pragma_Check_Float_Overflow
         | Pragma_Check_Name
         | Pragma_Check_Policy
         | Pragma_Compile_Time_Error
         | Pragma_Compile_Time_Warning
         | Pragma_Constant_After_Elaboration
         | Pragma_Contract_Cases
         | Pragma_Convention_Identifier
         | Pragma_CPP_Class
         | Pragma_CPP_Constructor
         | Pragma_CPP_Virtual
         | Pragma_CPP_Vtable
         | Pragma_CPU
         | Pragma_C_Pass_By_Copy
         | Pragma_Comment
         | Pragma_Common_Object
         | Pragma_Complete_Representation
         | Pragma_Complex_Representation
         | Pragma_Component_Alignment
         | Pragma_Controlled
         | Pragma_Convention
         | Pragma_Debug_Policy
         | Pragma_Depends
         | Pragma_Detect_Blocking
         | Pragma_Default_Initial_Condition
         | Pragma_Default_Scalar_Storage_Order
         | Pragma_Default_Storage_Pool
         | Pragma_Disable_Atomic_Synchronization
         | Pragma_Discard_Names
         | Pragma_Dispatching_Domain
         | Pragma_Effective_Reads
         | Pragma_Effective_Writes
         | Pragma_Eliminate
         | Pragma_Elaborate
         | Pragma_Elaborate_All
         | Pragma_Elaborate_Body
         | Pragma_Elaboration_Checks
         | Pragma_Enable_Atomic_Synchronization
         | Pragma_Export
         | Pragma_Export_Function
         | Pragma_Export_Object
         | Pragma_Export_Procedure
         | Pragma_Export_Value
         | Pragma_Export_Valued_Procedure
         | Pragma_Extend_System
         | Pragma_Extensions_Visible
         | Pragma_External
         | Pragma_External_Name_Casing
         | Pragma_Favor_Top_Level
         | Pragma_Fast_Math
         | Pragma_Finalize_Storage_Only
         | Pragma_Ghost
         | Pragma_Global
         | Pragma_Ident
         | Pragma_Implementation_Defined
         | Pragma_Implemented
         | Pragma_Implicit_Packing
         | Pragma_Import
         | Pragma_Import_Function
         | Pragma_Import_Object
         | Pragma_Import_Procedure
         | Pragma_Import_Valued_Procedure
         | Pragma_Independent
         | Pragma_Independent_Components
         | Pragma_Initial_Condition
         | Pragma_Initialize_Scalars
         | Pragma_Initializes
         | Pragma_Inline
         | Pragma_Inline_Always
         | Pragma_Inline_Generic
         | Pragma_Inspection_Point
         | Pragma_Interface
         | Pragma_Interface_Name
         | Pragma_Interrupt_Handler
         | Pragma_Interrupt_State
         | Pragma_Interrupt_Priority
         | Pragma_Invariant
         | Pragma_Keep_Names
         | Pragma_License
         | Pragma_Link_With
         | Pragma_Linker_Alias
         | Pragma_Linker_Constructor
         | Pragma_Linker_Destructor
         | Pragma_Linker_Options
         | Pragma_Linker_Section
         | Pragma_Lock_Free
         | Pragma_Locking_Policy
         | Pragma_Loop_Invariant
         | Pragma_Loop_Optimize
         | Pragma_Loop_Variant
         | Pragma_Machine_Attribute
         | Pragma_Main
         | Pragma_Main_Storage
         | Pragma_Max_Queue_Length
         | Pragma_Memory_Size
         | Pragma_No_Body
         | Pragma_No_Elaboration_Code_All
         | Pragma_No_Inline
         | Pragma_No_Return
         | Pragma_No_Run_Time
         | Pragma_No_Strict_Aliasing
         | Pragma_No_Tagged_Streams
         | Pragma_Normalize_Scalars
         | Pragma_Obsolescent
         | Pragma_Ordered
         | Pragma_Optimize
         | Pragma_Optimize_Alignment
         | Pragma_Overflow_Mode
         | Pragma_Overriding_Renamings
         | Pragma_Pack
         | Pragma_Part_Of
         | Pragma_Partition_Elaboration_Policy
         | Pragma_Passive
         | Pragma_Preelaborable_Initialization
         | Pragma_Polling
         | Pragma_Prefix_Exception_Messages
         | Pragma_Persistent_BSS
         | Pragma_Post
         | Pragma_Postcondition
         | Pragma_Post_Class
         | Pragma_Pre
         | Pragma_Precondition
         | Pragma_Predicate
         | Pragma_Predicate_Failure
         | Pragma_Preelaborate
         | Pragma_Pre_Class
         | Pragma_Priority
         | Pragma_Priority_Specific_Dispatching
         | Pragma_Profile
         | Pragma_Profile_Warnings
         | Pragma_Propagate_Exceptions
         | Pragma_Provide_Shift_Operators
         | Pragma_Psect_Object
         | Pragma_Pure
         | Pragma_Pure_Function
         | Pragma_Queuing_Policy
         | Pragma_Refined_Depends
         | Pragma_Refined_Global
         | Pragma_Refined_Post
         | Pragma_Refined_State
         | Pragma_Relative_Deadline
         | Pragma_Remote_Access_Type
         | Pragma_Remote_Call_Interface
         | Pragma_Remote_Types
         | Pragma_Restricted_Run_Time
         | Pragma_Rational
         | Pragma_Ravenscar
         | Pragma_Rename_Pragma
         | Pragma_Reviewable
         | Pragma_Secondary_Stack_Size
         | Pragma_Share_Generic
         | Pragma_Shared
         | Pragma_Shared_Passive
         | Pragma_Short_Circuit_And_Or
         | Pragma_Short_Descriptors
         | Pragma_Simple_Storage_Pool_Type
         | Pragma_SPARK_Mode
         | Pragma_Storage_Size
         | Pragma_Storage_Unit
         | Pragma_Static_Elaboration_Desired
         | Pragma_Stream_Convert
         | Pragma_Subtitle
         | Pragma_Suppress
         | Pragma_Suppress_Debug_Info
         | Pragma_Suppress_Exception_Locations
         | Pragma_Suppress_Initialization
         | Pragma_System_Name
         | Pragma_Task_Dispatching_Policy
         | Pragma_Task_Info
         | Pragma_Task_Name
         | Pragma_Task_Storage
         | Pragma_Test_Case
         | Pragma_Thread_Local_Storage
         | Pragma_Time_Slice
         | Pragma_Title
         | Pragma_Type_Invariant
         | Pragma_Type_Invariant_Class
         | Pragma_Unchecked_Union
         | Pragma_Unevaluated_Use_Of_Old
         | Pragma_Unimplemented_Unit
         | Pragma_Universal_Aliasing
         | Pragma_Universal_Data
         | Pragma_Unmodified
         | Pragma_Unreferenced
         | Pragma_Unreferenced_Objects
         | Pragma_Unreserve_All_Interrupts
         | Pragma_Unsuppress
         | Pragma_Unused
         | Pragma_Use_VADS_Size
         | Pragma_Volatile
         | Pragma_Volatile_Components
         | Pragma_Volatile_Full_Access
         | Pragma_Volatile_Function
         | Pragma_Warning_As_Error
         | Pragma_Weak_External
         | Pragma_Validity_Checks
      =>
         null;

      --------------------
      -- Unknown_Pragma --
      --------------------

      --  Should be impossible, since we excluded this case earlier on

      when Unknown_Pragma =>
         raise Program_Error;

   end case;

   return Pragma_Node;

   --------------------
   -- Error Handling --
   --------------------

exception
   when Error_Resync =>
      return Error;

end Prag;