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

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             F R O N T E N D                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2011, 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.      --

--                                                                          --

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

with System.Strings; use System.Strings;

with Atree;    use Atree;

with Checks;

with CStand;

with Debug;    use Debug;

with Elists;

with Exp_Dbug;

with Fmap;

with Fname.UF;

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 Par;

with Prep;

with Prepcomp;

with Restrict; use Restrict;

with Rident;   use Rident;

with Rtsfind;  use Rtsfind;

with Snames;   use Snames;

with Sprint;

with Scn;      use Scn;

with Sem;      use Sem;

with Sem_Aux;

with Sem_Ch8;  use Sem_Ch8;

with Sem_SCIL;

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 SCIL_LL;  use SCIL_LL;

with Targparm; use Targparm;

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 before Namet,

   --  since it uses names table entries.

   Rtsfind.Initialize;

   Atree.Initialize;

   Nlists.Initialize;

   Elists.Initialize;

   Lib.Load.Initialize;

   Sem_Aux.Initialize;

   Sem_Ch8.Initialize;

   Sem_Prag.Initialize;

   Fname.UF.Initialize;

   Checks.Initialize;

   Sem_Warn.Initialize;

   Prep.Initialize;

   if Generate_SCIL then

      SCIL_LL.Initialize;

   end if;

   --  Create package Standard

   CStand.Create_Standard;

   --  If the -gnatd.H flag is present, we are only interested in the Standard

   --  package, so the frontend has done its job here.

   if Debug_Flag_Dot_HH then

      return;

   end if;

   --  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;

   --  We set Parsing_Main_Extended_Source true here to cover processing of all

   --  the configuration pragma files, as well as the main source unit itself.

   Parsing_Main_Extended_Source := True;

   --  Now that the preprocessing situation is established, we are able to

   --  load the main source (this is no longer done by Lib.Load.Initialize).

   Lib.Load.Load_Main_Source;

   --  Return immediately if the main source could not be found

   if Sinput.Main_Source_File = No_Source_File then

      return;

   end if;

   --  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;

      --  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;

      --  Capture any modifications to suppress options from config pragmas

      Opt.Suppress_Options := Scope_Suppress;

   end;

   --  This is where we can capture the value of the compilation unit specific

   --  restrictions that have been set by the config pragma files (or from

   --  Targparm), for later restoration when processing e.g. subunits.

   Save_Config_Cunit_Boolean_Restrictions;

   --  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;

   --  Adjust Optimize_Alignment mode from debug switches if necessary

   if Debug_Flag_Dot_SS then

      Optimize_Alignment := 'S';

   elsif Debug_Flag_Dot_TT then

      Optimize_Alignment := 'T';

   end if;

   --  We have now processed the command line switches, and the configuration

   --  pragma files, 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;

   --  Check for file which contains No_Body pragma

   if Source_File_Is_No_Body (Source_Index (Main_Unit)) then

      Change_Main_Unit_To_Spec;

   end if;

   --  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));

   --  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));

   Parsing_Main_Extended_Source := 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;

   --  If we have restriction No_Exception_Propagation, and we did not have an

   --  explicit switch turning off Warn_On_Non_Local_Exception, then turn on

   --  this warning by default if we have encountered an exception handler.

   if Restriction_Check_Required (No_Exception_Propagation)

     and then not No_Warn_On_Non_Local_Exception

     and then Exception_Handler_Encountered

   then

      Warn_On_Non_Local_Exception := True;

   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 waiting warning messages

         Sem_Warn.Output_Non_Modified_In_Out_Warnings;

         Sem_Warn.Output_Unreferenced_Messages;

         Sem_Warn.Check_Unused_Withs;

         Sem_Warn.Output_Unused_Warnings_Off_Warnings;

      end if;

   end if;

   --  Qualify all entity names in inner packages, package bodies, etc.,

   --  except when compiling for the VM back-ends, which depend on having

   --  unqualified names in certain cases and handles the generation of

   --  qualified names when needed.

   if VM_Target = No_VM then

      Exp_Dbug.Qualify_All_Entity_Names;

   end if;

   --  SCIL backend requirement. Check that SCIL nodes associated with

   --  dispatching calls reference subprogram calls.

   if Generate_SCIL then

      pragma Debug (Sem_SCIL.Check_SCIL_Nodes (Cunit (Main_Unit)));

      null;

   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;

   --  Check again for configuration pragmas that appear in the context of

   --  the main unit. These pragmas only affect the main unit, and the

   --  corresponding flag is reset after each call to Semantics, but they

   --  may affect the generated ali for the unit, and therefore the flag

   --  must be set properly after compilation. Currently we only check for

   --  Initialize_Scalars, but others should be checked: as well???

   declare

      Item  : Node_Id;

   begin

      Item := First (Context_Items (Cunit (Main_Unit)));

      while Present (Item) loop

         if Nkind (Item) = N_Pragma

           and then Pragma_Name (Item) = Name_Initialize_Scalars

         then

            Initialize_Scalars := True;

         end if;

         Next (Item);

      end loop;

   end;

   --  If a mapping file has been specified by a -gnatem switch, update

   --  it if there has been some sources 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;