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------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                             F R O N T E N D                              --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2005, 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 2,  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 COPYING.  If not, write --
-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
-- Boston, MA 02110-1301, USA.                                              --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------
 
with GNAT.Strings; use GNAT.Strings;
 
with Atree;    use Atree;
with Checks;
with CStand;
with Debug;    use Debug;
with Elists;
with Exp_Dbug;
with Fmap;
with Fname.UF;
with Hostparm; use Hostparm;
with Inline;   use Inline;
with Lib;      use Lib;
with Lib.Load; use Lib.Load;
with Live;     use Live;
with Namet;    use Namet;
with Nlists;   use Nlists;
with Opt;      use Opt;
with Osint;
with Output;   use Output;
with Par;
with Prepcomp;
with Rtsfind;
with Sprint;
with Scn;      use Scn;
with Sem;      use Sem;
with Sem_Ch8;  use Sem_Ch8;
with Sem_Elab; use Sem_Elab;
with Sem_Prag; use Sem_Prag;
with Sem_Warn; use Sem_Warn;
with Sinfo;    use Sinfo;
with Sinput;   use Sinput;
with Sinput.L; use Sinput.L;
with Tbuild;   use Tbuild;
with Types;    use Types;
 
procedure Frontend is
      Config_Pragmas : List_Id;
      --  Gather configuration pragmas
 
begin
   --  Carry out package initializations. These are initializations which
   --  might logically be performed at elaboration time, were it not for
   --  the fact that we may be doing things more than once in the big loop
   --  over files. Like elaboration, the order in which these calls are
   --  made is in some cases important. For example, Lib cannot be
   --  initialized until Namet, since it uses names table entries.
 
   Rtsfind.Initialize;
   Atree.Initialize;
   Nlists.Initialize;
   Elists.Initialize;
   Lib.Load.Initialize;
   Sem_Ch8.Initialize;
   Fname.UF.Initialize;
   Checks.Initialize;
 
   --  Create package Standard
 
   CStand.Create_Standard;
 
   --  Check possible symbol definitions specified by -gnateD switches
 
   Prepcomp.Process_Command_Line_Symbol_Definitions;
 
   --  If -gnatep= was specified, parse the preprocessing data file
 
   if Preprocessing_Data_File /= null then
      Name_Len := Preprocessing_Data_File'Length;
      Name_Buffer (1 .. Name_Len) := Preprocessing_Data_File.all;
      Prepcomp.Parse_Preprocessing_Data_File (Name_Find);
 
   --  Otherwise, check if there were preprocessing symbols on the command
   --  line and set preprocessing if there are.
 
   else
      Prepcomp.Check_Symbols;
   end if;
 
   --  Now that the preprocessing situation is established, we are able to
   --  load the main source (this is no longer done by Lib.Load.Initalize).
 
   Lib.Load.Load_Main_Source;
 
   --  Read and process configuration pragma files if present
 
   declare
      Save_Style_Check : constant Boolean := Opt.Style_Check;
      --  Save style check mode so it can be restored later
 
      Source_Config_File : Source_File_Index;
      --  Source reference for -gnatec configuration file
 
      Prag : Node_Id;
 
   begin
      --  We always analyze config files with style checks off, since
      --  we don't want a miscellaneous gnat.adc that is around to
      --  discombobulate intended -gnatg or -gnaty compilations. We
      --  also disconnect checking for maximum line length.
 
      Opt.Style_Check := False;
      Style_Check := False;
      Opt.Max_Line_Length := Int (Column_Number'Last);
 
      --  Capture current suppress options, which may get modified
 
      Scope_Suppress := Opt.Suppress_Options;
 
      --  First deal with gnat.adc file
 
      if Opt.Config_File then
         Name_Buffer (1 .. 8) := "gnat.adc";
         Name_Len := 8;
         Source_gnat_adc := Load_Config_File (Name_Enter);
 
         if Source_gnat_adc /= No_Source_File then
            Initialize_Scanner (No_Unit, Source_gnat_adc);
            Config_Pragmas := Par (Configuration_Pragmas => True);
 
         else
            Config_Pragmas := Empty_List;
         end if;
 
      else
         Config_Pragmas := Empty_List;
      end if;
 
      --  Now deal with specified config pragmas files if there are any
 
      if Opt.Config_File_Names /= null then
         for Index in Opt.Config_File_Names'Range loop
            Name_Len := Config_File_Names (Index)'Length;
            Name_Buffer (1 .. Name_Len) := Config_File_Names (Index).all;
            Source_Config_File := Load_Config_File (Name_Enter);
 
            if Source_Config_File = No_Source_File then
               Osint.Fail
                 ("cannot find configuration pragmas file ",
                  Config_File_Names (Index).all);
            end if;
 
            Initialize_Scanner (No_Unit, Source_Config_File);
            Append_List_To
              (Config_Pragmas, Par (Configuration_Pragmas => True));
         end loop;
      end if;
 
      --  Now analyze all pragmas except those whose analysis must be
      --  deferred till after the main unit is analyzed.
 
      if Config_Pragmas /= Error_List
        and then Operating_Mode /= Check_Syntax
      then
         Prag := First (Config_Pragmas);
         while Present (Prag) loop
            if not Delay_Config_Pragma_Analyze (Prag) then
               Analyze_Pragma (Prag);
            end if;
 
            Next (Prag);
         end loop;
      end if;
 
      --  Restore style check, but if config file turned on checks, leave on!
 
      Opt.Style_Check := Save_Style_Check or Style_Check;
      Opt.Max_Line_Length := Hostparm.Max_Line_Length;
 
      --  Capture any modifications to suppress options from config pragmas
 
      Opt.Suppress_Options := Scope_Suppress;
   end;
 
   --  If there was a -gnatem switch, initialize the mappings of unit names to
   --  file names and of file names to path names from the mapping file.
 
   if Mapping_File_Name /= null then
      Fmap.Initialize (Mapping_File_Name.all);
   end if;
 
   --  We have now processed the command line switches, and the gnat.adc
   --  file, so this is the point at which we want to capture the values
   --  of the configuration switches (see Opt for further details).
 
   Opt.Register_Opt_Config_Switches;
 
   --  Initialize the scanner. Note that we do this after the call to
   --  Create_Standard, which uses the scanner in its processing of
   --  floating-point bounds.
 
   Initialize_Scanner (Main_Unit, Source_Index (Main_Unit));
 
   --  Output header if in verbose mode or full list mode
 
   if Verbose_Mode or Full_List then
      Write_Eol;
 
      if Operating_Mode = Generate_Code then
         Write_Str ("Compiling: ");
      else
         Write_Str ("Checking: ");
      end if;
 
      Write_Name (Full_File_Name (Current_Source_File));
 
      if not Debug_Flag_7 then
         Write_Str (" (source file time stamp: ");
         Write_Time_Stamp (Current_Source_File);
         Write_Char (')');
      end if;
 
      Write_Eol;
   end if;
 
   --  Here we call the parser to parse the compilation unit (or units in
   --  the check syntax mode, but in that case we won't go on to the
   --  semantics in any case).
 
   Discard_List (Par (Configuration_Pragmas => False));
 
   --  The main unit is now loaded, and subunits of it can be loaded,
   --  without reporting spurious loading circularities.
 
   Set_Loading (Main_Unit, False);
 
   --  Now that the main unit is installed, we can complete the analysis
   --  of the pragmas in gnat.adc and the configuration file, that require
   --  a context for their semantic processing.
 
   if Config_Pragmas /= Error_List
     and then Operating_Mode /= Check_Syntax
   then
      --  Pragmas that require some semantic activity, such as
      --  Interrupt_State, cannot be processed until the main unit
      --  is installed, because they require a compilation unit on
      --  which to attach with_clauses, etc. So analyze them now.
 
      declare
         Prag : Node_Id;
 
      begin
         Prag := First (Config_Pragmas);
         while Present (Prag) loop
            if Delay_Config_Pragma_Analyze (Prag) then
               Analyze_Pragma (Prag);
            end if;
 
            Next (Prag);
         end loop;
      end;
   end if;
 
   --  Now on to the semantics. Skip if in syntax only mode
 
   if Operating_Mode /= Check_Syntax then
 
      --  Install the configuration pragmas in the tree
 
      Set_Config_Pragmas (Aux_Decls_Node (Cunit (Main_Unit)), Config_Pragmas);
 
      --  Following steps are skipped if we had a fatal error during parsing
 
      if not Fatal_Error (Main_Unit) then
 
         --  Reset Operating_Mode to Check_Semantics for subunits. We cannot
         --  actually generate code for subunits, so we suppress expansion.
         --  This also corrects certain problems that occur if we try to
         --  incorporate subunits at a lower level.
 
         if Operating_Mode = Generate_Code
            and then Nkind (Unit (Cunit (Main_Unit))) = N_Subunit
         then
            Operating_Mode := Check_Semantics;
         end if;
 
         --  Analyze (and possibly expand) main unit
 
         Scope_Suppress := Suppress_Options;
         Semantics (Cunit (Main_Unit));
 
         --  Cleanup processing after completing main analysis
 
         if Operating_Mode = Generate_Code
            or else (Operating_Mode = Check_Semantics
                      and then ASIS_Mode)
         then
            Instantiate_Bodies;
         end if;
 
         if Operating_Mode = Generate_Code then
            if Inline_Processing_Required then
               Analyze_Inlined_Bodies;
            end if;
 
            --  Remove entities from program that do not have any
            --  execution time references.
 
            if Debug_Flag_UU then
               Collect_Garbage_Entities;
            end if;
 
            Check_Elab_Calls;
         end if;
 
         --  List library units if requested
 
         if List_Units then
            Lib.List;
         end if;
 
         --  Output any messages for unreferenced entities
 
         Output_Unreferenced_Messages;
         Sem_Warn.Check_Unused_Withs;
      end if;
   end if;
 
   --  Qualify all entity names in inner packages, package bodies, etc.,
   --  except when compiling for the JVM back end, which depends on
   --  having unqualified names in certain cases and handles the
   --  generation of qualified names when needed.
 
   if not Java_VM then
      Exp_Dbug.Qualify_All_Entity_Names;
   end if;
 
   --  Dump the source now. Note that we do this as soon as the analysis
   --  of the tree is complete, because it is not just a dump in the case
   --  of -gnatD, where it rewrites all source locations in the tree.
 
   Sprint.Source_Dump;
 
   --  If a mapping file has been specified by a -gnatem switch, update
   --  it if there has been some sourcs that were not in the mappings.
 
   if Mapping_File_Name /= null then
      Fmap.Update_Mapping_File (Mapping_File_Name.all);
   end if;
 
   return;
end Frontend;