freepascal.compiler/compiler/nobj.pas

{
    Copyright (c) 1998-2002 by Florian Klaempfl

    Routines for the code generation of data structures
    like VMT, Messages, VTables, Interfaces descs

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT 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
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
unit nobj;

{$i fpcdefs.inc}

interface

    uses
       cutils,cclasses,
       globtype,
       symdef,symsym,
       aasmbase,aasmtai,aasmdata
       ;

    type
      pprocdefentry = ^tprocdefentry;
      tprocdefentry = record
         data    : tprocdef;
         hidden  : boolean;
         visible : boolean;
      end;

      { tvmtsymentry }

      tvmtsymentry = class(TFPHashObject)
        procdeflist : TFPList;
        constructor Create(AList:TFPHashObjectList;const AName:shortstring);
        destructor Destroy;override;
      end;

      TVMTBuilder=class
      private
        _Class : tobjectdef;
        VMTSymEntryList : TFPHashObjectList;
        has_constructor,
        has_virtual_method : boolean;
        function is_new_vmt_entry(VMTSymEntry:TVMTSymEntry;pd:tprocdef):boolean;
        procedure add_new_vmt_entry(VMTSymEntry:TVMTSymEntry;pd:tprocdef);
        procedure add_vmt_entries(objdef:tobjectdef);
        function  intf_search_procdef_by_name(proc: tprocdef;const name: string): tprocdef;
        procedure intf_get_procdefs(ImplIntf:TImplementedInterface;IntfDef:TObjectDef);
        procedure intf_get_procdefs_recursive(ImplIntf:TImplementedInterface;IntfDef:TObjectDef);
        procedure intf_optimize_vtbls;
        procedure intf_allocate_vtbls;
      public
        constructor create(c:tobjectdef);
        destructor  destroy;override;
        procedure generate_vmt;
      end;

    type
      pprocdeftree = ^tprocdeftree;
      tprocdeftree = record
         data : tprocdef;
         nl   : tasmlabel;
         l,r  : pprocdeftree;
      end;

      TVMTWriter=class
      private
        _Class : tobjectdef;
        { message tables }
        root : pprocdeftree;
        procedure disposeprocdeftree(p : pprocdeftree);
        procedure insertmsgint(p:TObject;arg:pointer);
        procedure insertmsgstr(p:TObject;arg:pointer);
        procedure insertint(p : pprocdeftree;var at : pprocdeftree;var count:longint);
        procedure insertstr(p : pprocdeftree;var at : pprocdeftree;var count:longint);
        procedure writenames(p : pprocdeftree);
        procedure writeintentry(p : pprocdeftree);
        procedure writestrentry(p : pprocdeftree);
{$ifdef WITHDMT}
        { dmt }
        procedure insertdmtentry(p:TObject;arg:pointer);
        procedure writedmtindexentry(p : pprocdeftree);
        procedure writedmtaddressentry(p : pprocdeftree);
{$endif}
        { published methods }
        procedure do_count_published_methods(p:TObject;arg:pointer);
        procedure do_gen_published_methods(p:TObject;arg:pointer);
        { virtual methods }
        procedure writevirtualmethods(List:TAsmList);
        { interface tables }
        function  intf_get_vtbl_name(AImplIntf:TImplementedInterface): string;
        procedure intf_create_vtbl(rawdata: TAsmList;AImplIntf:TImplementedInterface);
        procedure intf_gen_intf_ref(rawdata: TAsmList;AImplIntf:TImplementedInterface);
        function  intf_write_table:TAsmLabel;
        { generates the message tables for a class }
        function  genstrmsgtab : tasmlabel;
        function  genintmsgtab : tasmlabel;
        function  genpublishedmethodstable : tasmlabel;
        function  generate_field_table : tasmlabel;
{$ifdef WITHDMT}
        { generates a DMT for _class }
        function  gendmt : tasmlabel;
{$endif WITHDMT}
      public
        constructor create(c:tobjectdef);
        destructor destroy;override;
        { write the VMT to al_globals }
        procedure writevmt;
        procedure writeinterfaceids;
      end;

implementation

    uses
       SysUtils,
       globals,verbose,systems,
       symtable,symconst,symtype,defcmp,
       dbgbase,
       ncgrtti
       ;


{*****************************************************************************
                              TVMTSymEntry
*****************************************************************************}

    constructor tvmtsymentry.Create(AList:TFPHashObjectList;const AName:shortstring);
      begin
        inherited Create(AList,AName);
        procdeflist:=TFPList.Create;
      end;


    destructor TVMTSymEntry.Destroy;
      var
        i : longint;
      begin
        for i:=0 to procdeflist.Count-1 do
          Dispose(pprocdefentry(procdeflist[i]));
        procdeflist.free;
        inherited Destroy;
      end;


{*****************************************************************************
                              TVMTBuilder
*****************************************************************************}

    constructor TVMTBuilder.create(c:tobjectdef);
      begin
        inherited Create;
        _Class:=c;
        VMTSymEntryList:=TFPHashObjectList.Create;
      end;


    destructor TVMTBuilder.destroy;
      begin
        VMTSymEntryList.free;
      end;


    procedure TVMTBuilder.add_new_vmt_entry(VMTSymEntry:TVMTSymEntry;pd:tprocdef);
      var
        procdefcoll : pprocdefentry;
        i : longint;
        oldpd : tprocdef;
      begin
        if (_class=pd._class) then
          begin
            { new entry is needed, override was not possible }
            if (po_overridingmethod in pd.procoptions) then
              MessagePos1(pd.fileinfo,parser_e_nothing_to_be_overridden,pd.fullprocname(false));

            { check that all methods have overload directive }
            if not(m_fpc in current_settings.modeswitches) then
              begin
                for i:=0 to VMTSymentry.ProcdefList.Count-1 do
                  begin
                    oldpd:=pprocdefentry(VMTSymentry.ProcdefList[i])^.data;
                    if (oldpd._class=pd._class) and
                       ((po_overload in pd.procoptions)<>(po_overload in oldpd.procoptions)) then
                      begin
                        MessagePos1(pd.fileinfo,parser_e_no_overload_for_all_procs,pd.procsym.realname);
                        { recover }
                        include(oldpd.procoptions,po_overload);
                        include(pd.procoptions,po_overload);
                      end;
                  end;
              end;
          end;

        { generate new entry }
        new(procdefcoll);
        procdefcoll^.data:=pd;
        procdefcoll^.hidden:=false;
        procdefcoll^.visible:=pd.is_visible_for_object(_class,nil);
        VMTSymEntry.ProcdefList.Add(procdefcoll);

        { Register virtual method and give it a number }
        if (po_virtualmethod in pd.procoptions) then
          begin
             if not assigned(_class.VMTEntries) then
               _class.VMTEntries:=TFPObjectList.Create(false);
             if pd.extnumber=$ffff then
               pd.extnumber:=_class.VMTEntries.Count
             else
               begin
                 if pd.extnumber<>_class.VMTEntries.Count then
                   internalerror(200611081);
               end;
             _class.VMTEntries.Add(pd);
             has_virtual_method:=true;
          end;

        if (pd.proctypeoption=potype_constructor) then
          has_constructor:=true;
      end;


    function TVMTBuilder.is_new_vmt_entry(VMTSymEntry:TVMTSymEntry;pd:tprocdef):boolean;
      const
        po_comp = [po_classmethod,po_virtualmethod,po_staticmethod,po_interrupt,po_iocheck,po_msgstr,po_msgint,
                   po_exports,po_varargs,po_explicitparaloc,po_nostackframe];
      var
        i : longint;
        is_visible,
        hasoverloads,
        pdoverload : boolean;
        procdefcoll : pprocdefentry;
      begin
        result:=false;
        { is this procdef visible from the class that we are
          generating. This will be used to hide the other procdefs.
          When the symbol is not visible we don't hide the other
          procdefs, because they can be reused in the next class.
          The check to skip the invisible methods that are in the
          list is futher down in the code }
        is_visible:=pd.is_visible_for_object(_class,nil);
        { Load other values for easier readability }
        hasoverloads:=(tprocsym(pd.procsym).ProcdefList.Count>1);
        pdoverload:=(po_overload in pd.procoptions);

        { compare with all stored definitions }
        for i:=0 to VMTSymEntry.ProcdefList.Count-1 do
          begin
            procdefcoll:=pprocdefentry(VMTSymEntry.ProcdefList[i]);
            { skip definitions that are already hidden }
            if procdefcoll^.hidden then
              continue;

            { check if one of the two methods has virtual }
            if (po_virtualmethod in procdefcoll^.data.procoptions) or
               (po_virtualmethod in pd.procoptions) then
              begin
                { if the current definition has no virtual then hide the
                  old virtual if the new definition has the same arguments or
                  when it has no overload directive and no overloads }
                if not(po_virtualmethod in pd.procoptions) then
                  begin
                    if procdefcoll^.visible and
                       (
                        not(pdoverload or hasoverloads) or
                        (compare_paras(procdefcoll^.data.paras,pd.paras,cp_all,[])>=te_equal)
                       ) then
                      begin
                        if is_visible then
                          procdefcoll^.hidden:=true;
                        if (_class=pd._class) and not(po_reintroduce in pd.procoptions) then
                          MessagePos1(pd.fileinfo,parser_w_should_use_override,pd.fullprocname(false));
                      end;
                  end
                { if both are virtual we check the header }
                else if (po_virtualmethod in pd.procoptions) and
                        (po_virtualmethod in procdefcoll^.data.procoptions) then
                  begin
                    { new one has not override }
                    if is_class(_class) and
                       not(po_overridingmethod in pd.procoptions) then
                      begin
                        { we start a new virtual tree, hide the old }
                        if (not(pdoverload or hasoverloads) or
                            (compare_paras(procdefcoll^.data.paras,pd.paras,cp_all,[])>=te_equal)) and
                           (procdefcoll^.visible) then
                          begin
                            if is_visible then
                              procdefcoll^.hidden:=true;
                            if (_class=pd._class) and not(po_reintroduce in pd.procoptions) then
                              MessagePos1(pd.fileinfo,parser_w_should_use_override,pd.fullprocname(false));
                          end;
                      end
                    { same parameters }
                    else if (compare_paras(procdefcoll^.data.paras,pd.paras,cp_all,[])>=te_equal) then
                      begin
                        { overload is inherited }
                        if (po_overload in procdefcoll^.data.procoptions) then
                         include(pd.procoptions,po_overload);

                        { inherite calling convention when it was force and the
                          current definition has none force }
                        if (po_hascallingconvention in procdefcoll^.data.procoptions) and
                           not(po_hascallingconvention in pd.procoptions) then
                          begin
                            pd.proccalloption:=procdefcoll^.data.proccalloption;
                            include(pd.procoptions,po_hascallingconvention);
                          end;

                        { the flags have to match except abstract and override }
                        { only if both are virtual !!  }
                        if (procdefcoll^.data.proccalloption<>pd.proccalloption) or
                           (procdefcoll^.data.proctypeoption<>pd.proctypeoption) or
                           ((procdefcoll^.data.procoptions*po_comp)<>(pd.procoptions*po_comp)) then
                           begin
                             MessagePos1(pd.fileinfo,parser_e_header_dont_match_forward,pd.fullprocname(false));
                             tprocsym(procdefcoll^.data.procsym).write_parameter_lists(pd);
                           end;

                        { error, if the return types aren't equal }
                        if not(equal_defs(procdefcoll^.data.returndef,pd.returndef)) and
                           not((procdefcoll^.data.returndef.typ=objectdef) and
                            (pd.returndef.typ=objectdef) and
                            is_class_or_interface(procdefcoll^.data.returndef) and
                            is_class_or_interface(pd.returndef) and
                            (tobjectdef(pd.returndef).is_related(tobjectdef(procdefcoll^.data.returndef)))) then
                          begin
                            if not((m_delphi in current_settings.modeswitches) and
                                   is_interface(_class)) then
                              Message2(parser_e_overridden_methods_not_same_ret,pd.fullprocname(false),
                                       procdefcoll^.data.fullprocname(false))
                            else
                              { Delphi allows changing the result type of interface methods from anything to
                                anything (JM) }
                              Message2(parser_w_overridden_methods_not_same_ret,pd.fullprocname(false),
                                       procdefcoll^.data.fullprocname(false));
                          end;
                        { check if the method to override is visible, check is only needed
                          for the current parsed class. Parent classes are already validated and
                          need to include all virtual methods including the ones not visible in the
                          current class }
                        if (_class=pd._class) and
                           (po_overridingmethod in pd.procoptions) and
                           (not procdefcoll^.visible) then
                          MessagePos1(pd.fileinfo,parser_e_nothing_to_be_overridden,pd.fullprocname(false));

                        { override old virtual method in VMT }
                        if (procdefcoll^.data.extnumber>=_class.VMTEntries.Count) or
                           (_class.VMTEntries[procdefcoll^.data.extnumber]<>procdefcoll^.data) then
                          internalerror(200611084);
                        _class.VMTEntries[procdefcoll^.data.extnumber]:=pd;
                        pd.extnumber:=procdefcoll^.data.extnumber;
                        procdefcoll^.data:=pd;
                        if is_visible then
                          procdefcoll^.visible:=true;

                        exit;
                      end
                    { different parameters }
                    else
                     begin
                       { when we got an override directive then can search futher for
                         the procedure to override.
                         If we are starting a new virtual tree then hide the old tree }
                       if not(po_overridingmethod in pd.procoptions) and
                          not pdoverload then
                        begin
                          if is_visible then
                            procdefcoll^.hidden:=true;
                          if (_class=pd._class) and not(po_reintroduce in pd.procoptions) then
                            MessagePos1(pd.fileinfo,parser_w_should_use_override,pd.fullprocname(false));
                        end;
                     end;
                  end
                else
                  begin
                    { the new definition is virtual and the old static, we hide the old one
                      if the new defintion has not the overload directive }
                    if is_visible and
                       (
                        (not(pdoverload or hasoverloads)) or
                        (compare_paras(procdefcoll^.data.paras,pd.paras,cp_all,[])>=te_equal)
                       ) then
                      procdefcoll^.hidden:=true;
                  end;
              end
            else
              begin
                { both are static, we hide the old one if the new defintion
                  has not the overload directive }
                if is_visible and
                   (
                    (not pdoverload) or
                    (compare_paras(procdefcoll^.data.paras,pd.paras,cp_all,[])>=te_equal)
                   ) then
                  procdefcoll^.hidden:=true;
               end;
          end;
        { No entry found, we need to create a new entry }
        result:=true;
      end;


    procedure TVMTBuilder.add_vmt_entries(objdef:tobjectdef);
      var
         pd  : tprocdef;
         i,j : longint;
         sym : tsym;
         VMTSymEntry : TVMTSymEntry;
      begin
        { start with the base class }
        if assigned(objdef.childof) then
          add_vmt_entries(objdef.childof);
        { process all procsyms }
        for i:=0 to objdef.symtable.SymList.Count-1 do
          begin
            sym:=tsym(objdef.symtable.SymList[i]);
            if sym.typ=procsym then
              begin
                { Find VMT procsym }
                VMTSymEntry:=TVMTSymEntry(VMTSymEntryList.Find(sym.name));
                if not assigned(VMTSymEntry) then
                  VMTSymEntry:=TVMTSymEntry.Create(VMTSymEntryList,sym.name);
                { Add all procdefs }
                for j:=0 to Tprocsym(sym).ProcdefList.Count-1 do
                  begin
                    pd:=tprocdef(Tprocsym(sym).ProcdefList[j]);
                    if pd.procsym=tprocsym(sym) then
                      begin
                        if is_new_vmt_entry(VMTSymEntry,pd) then
                          add_new_vmt_entry(VMTSymEntry,pd);
                      end;
                  end;
              end;
          end;
      end;


    function TVMTBuilder.intf_search_procdef_by_name(proc: tprocdef;const name: string): tprocdef;
      const
        po_comp = [po_classmethod,po_staticmethod,po_interrupt,po_iocheck,po_msgstr,po_msgint,
                   po_exports,po_varargs,po_explicitparaloc,po_nostackframe];
      var
        sym: tsym;
        implprocdef : Tprocdef;
        i: cardinal;
      begin
        result:=nil;

        sym:=tsym(search_class_member(_class,name));
        if assigned(sym) and
           (sym.typ=procsym) then
          begin
            { when the definition has overload directive set, we search for
              overloaded definitions in the class, this only needs to be done once
              for class entries as the tree keeps always the same }
            if (not tprocsym(sym).overloadchecked) and
               (po_overload in tprocdef(tprocsym(sym).ProcdefList[0]).procoptions) and
               (tprocsym(sym).owner.symtabletype=ObjectSymtable) then
             search_class_overloads(tprocsym(sym));

            for i:=0 to Tprocsym(sym).ProcdefList.Count-1 do
              begin
                implprocdef:=tprocdef(Tprocsym(sym).ProcdefList[i]);
                if (compare_paras(proc.paras,implprocdef.paras,cp_none,[])>=te_equal) and
                   (proc.proccalloption=implprocdef.proccalloption) and
                   (proc.proctypeoption=implprocdef.proctypeoption) and
                   ((proc.procoptions*po_comp)=((implprocdef.procoptions+[po_virtualmethod])*po_comp)) then
                  begin
                    result:=implprocdef;
                    exit;
                  end;
              end;
          end;
      end;


    procedure TVMTBuilder.intf_get_procdefs(ImplIntf:TImplementedInterface;IntfDef:TObjectDef);
      var
        i   : longint;
        def : tdef;
        hs,
        prefix,
        mappedname: string;
        implprocdef: tprocdef;
      begin
        prefix:=ImplIntf.IntfDef.symtable.name^+'.';
        for i:=0 to IntfDef.symtable.DefList.Count-1 do
          begin
            def:=tdef(IntfDef.symtable.DefList[i]);
            if def.typ=procdef then
              begin
                { Find implementing procdef
                   1. Check for mapped name
                   2. Use symbol name }
                implprocdef:=nil;
                hs:=prefix+tprocdef(def).procsym.name;
                mappedname:=ImplIntf.GetMapping(hs);
                if mappedname<>'' then
                  implprocdef:=intf_search_procdef_by_name(tprocdef(def),mappedname);
                if not assigned(implprocdef) then
                  implprocdef:=intf_search_procdef_by_name(tprocdef(def),tprocdef(def).procsym.name);
                { Add procdef to the implemented interface }
                if assigned(implprocdef) then
                  ImplIntf.AddImplProc(implprocdef)
                else
                  if ImplIntf.IntfDef.iitype = etStandard then
                    Message1(sym_e_no_matching_implementation_found,tprocdef(def).fullprocname(false));
              end;
          end;
      end;


    procedure TVMTBuilder.intf_get_procdefs_recursive(ImplIntf:TImplementedInterface;IntfDef:TObjectDef);
      begin
        if assigned(IntfDef.childof) then
          intf_get_procdefs_recursive(ImplIntf,IntfDef.childof);
        intf_get_procdefs(ImplIntf,IntfDef);
      end;


    procedure TVMTBuilder.intf_optimize_vtbls;
      type
        tcompintfentry = record
          weight: longint;
          compintf: longint;
        end;
        { Max 1000 interface in the class header interfaces it's enough imho }
        tcompintfs = array[0..1000] of tcompintfentry;
        pcompintfs = ^tcompintfs;
        tequals    = array[0..1000] of longint;
        pequals    = ^tequals;
        timpls    = array[0..1000] of longint;
        pimpls    = ^timpls;
      var
        equals: pequals;
        compats: pcompintfs;
        impls: pimpls;
        ImplIntfCount,
        w,i,j,k: longint;
        ImplIntfI,
        ImplIntfJ  : TImplementedInterface;
        cij: boolean;
        cji: boolean;
      begin
        ImplIntfCount:=_class.ImplementedInterfaces.count;
        if ImplIntfCount>=High(tequals) then
          Internalerror(200006135);
        getmem(compats,sizeof(tcompintfentry)*ImplIntfCount);
        getmem(equals,sizeof(longint)*ImplIntfCount);
        getmem(impls,sizeof(longint)*ImplIntfCount);
        filldword(compats^,(sizeof(tcompintfentry) div sizeof(dword))*ImplIntfCount,dword(-1));
        filldword(equals^,ImplIntfCount,dword(-1));
        filldword(impls^,ImplIntfCount,dword(-1));
        { ismergepossible is a containing relation
          meaning of ismergepossible(a,b,w) =
          if implementorfunction map of a is contained implementorfunction map of b
          imp(a,b) and imp(b,c) => imp(a,c) ; imp(a,b) and imp(b,a) => a == b
        }
        { the order is very important for correct allocation }
        for i:=0 to ImplIntfCount-1 do
          begin
            for j:=i+1 to ImplIntfCount-1 do
              begin
                ImplIntfI:=TImplementedInterface(_class.ImplementedInterfaces[i]);
                ImplIntfJ:=TImplementedInterface(_class.ImplementedInterfaces[j]);
                cij:=ImplIntfI.IsImplMergePossible(ImplIntfJ,w);
                cji:=ImplIntfJ.IsImplMergePossible(ImplIntfI,w);
                if cij and cji then { i equal j }
                  begin
                    { get minimum index of equal }
                    if equals^[j]=-1 then
                      equals^[j]:=i;
                  end
                else if cij then
                  begin
                    { get minimum index of maximum weight  }
                    if compats^[i].weight<w then
                      begin
                        compats^[i].weight:=w;
                        compats^[i].compintf:=j;
                      end;
                  end
                else if cji then
                  begin
                    { get minimum index of maximum weight  }
                    if (compats^[j].weight<w) then
                      begin
                        compats^[j].weight:=w;
                        compats^[j].compintf:=i;
                      end;
                  end;
              end;
          end;
        { Reset, no replacements by default }
        for i:=0 to ImplIntfCount-1 do
          impls^[i]:=i;
        { Replace vtbls when equal or compat, repeat
          until there are no replacements possible anymore. This is
          needed for the cases like:
            First loop: 2->3, 3->1
            Second loop: 2->1 (because 3 was replaced with 1)
        }
        repeat
          k:=0;
          for i:=0 to ImplIntfCount-1 do
            begin
              if compats^[impls^[i]].compintf<>-1 then
                impls^[i]:=compats^[impls^[i]].compintf
              else if equals^[impls^[i]]<>-1 then
                impls^[i]:=equals^[impls^[i]]
              else
                inc(k);
            end;
        until k=ImplIntfCount;
        { Update the VtblImplIntf }
        for i:=0 to ImplIntfCount-1 do
          begin
            ImplIntfI:=TImplementedInterface(_class.ImplementedInterfaces[i]);
            ImplIntfI.VtblImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[impls^[i]]);
          end;
        freemem(compats);
        freemem(equals);
        freemem(impls);
      end;


    procedure TVMTBuilder.intf_allocate_vtbls;
      var
        i : longint;
        ImplIntf : TImplementedInterface;
      begin
        { Allocation vtbl space }
        for i:=0 to _class.ImplementedInterfaces.count-1 do
          begin
            ImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[i]);
            { if it implements itself }
            if ImplIntf.VtblImplIntf=ImplIntf then
              begin
                { allocate a pointer in the object memory }
                with tObjectSymtable(_class.symtable) do
                  begin
                    datasize:=align(datasize,sizeof(aint));
                    ImplIntf.Ioffset:=datasize;
                    inc(datasize,sizeof(aint));
                  end;
              end;
          end;
        { Update ioffset of current interface with the ioffset from
          the interface that is reused to implements this interface }
        for i:=0 to _class.ImplementedInterfaces.count-1 do
          begin
            ImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[i]);
            if ImplIntf.VtblImplIntf<>ImplIntf then
              ImplIntf.Ioffset:=ImplIntf.VtblImplIntf.Ioffset;
          end;
      end;


    procedure TVMTBuilder.generate_vmt;
      var
        i : longint;
        ImplIntf : TImplementedInterface;
      begin
        { Find VMT entries }
        has_constructor:=false;
        has_virtual_method:=false;
        add_vmt_entries(_class);
        if not(is_interface(_class)) and
           has_virtual_method and
           not(has_constructor) then
          Message1(parser_w_virtual_without_constructor,_class.objrealname^);

        { Find Procdefs implementing the interfaces }
        if assigned(_class.ImplementedInterfaces) then
          begin
            { Collect implementor functions into the tImplementedInterface.procdefs }
            for i:=0 to _class.ImplementedInterfaces.count-1 do
              begin
                ImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[i]);
                intf_get_procdefs_recursive(ImplIntf,ImplIntf.IntfDef);
              end;
            { Optimize interface tables to reuse wrappers }
            intf_optimize_vtbls;
            { Allocate interface tables }
            intf_allocate_vtbls;
          end;
      end;


{*****************************************************************************
                                TVMTWriter
*****************************************************************************}

    constructor TVMTWriter.create(c:tobjectdef);
      begin
        inherited Create;
        _Class:=c;
      end;


    destructor TVMTWriter.destroy;
      begin
      end;


{**************************************
           Message Tables
**************************************}

    procedure TVMTWriter.disposeprocdeftree(p : pprocdeftree);
      begin
         if assigned(p^.l) then
           disposeprocdeftree(p^.l);
         if assigned(p^.r) then
           disposeprocdeftree(p^.r);
         dispose(p);
      end;


    procedure TVMTWriter.insertint(p : pprocdeftree;var at : pprocdeftree;var count:longint);

      begin
         if at=nil then
           begin
              at:=p;
              inc(count);
           end
         else
           begin
              if p^.data.messageinf.i<at^.data.messageinf.i then
                insertint(p,at^.l,count)
              else if p^.data.messageinf.i>at^.data.messageinf.i then
                insertint(p,at^.r,count)
              else
                Message1(parser_e_duplicate_message_label,tostr(p^.data.messageinf.i));
           end;
      end;

    procedure TVMTWriter.insertstr(p : pprocdeftree;var at : pprocdeftree;var count:longint);

      var
         i : integer;

      begin
         if at=nil then
           begin
              at:=p;
              inc(count);
           end
         else
           begin
              i:=CompareStr(p^.data.messageinf.str^,at^.data.messageinf.str^);
              if i<0 then
                insertstr(p,at^.l,count)
              else if i>0 then
                insertstr(p,at^.r,count)
              else
                Message1(parser_e_duplicate_message_label,p^.data.messageinf.str^);
           end;
      end;


    procedure TVMTWriter.insertmsgint(p:TObject;arg:pointer);
      var
        i  : longint;
        pd : Tprocdef;
        pt : pprocdeftree;
      begin
        if tsym(p).typ<>procsym then
          exit;
        for i:=0 to Tprocsym(p).ProcdefList.Count-1 do
          begin
            pd:=tprocdef(Tprocsym(p).ProcdefList[i]);
            if po_msgint in pd.procoptions then
              begin
                new(pt);
                pt^.data:=pd;
                pt^.l:=nil;
                pt^.r:=nil;
                insertint(pt,root,plongint(arg)^);
              end;
          end;
      end;


    procedure TVMTWriter.insertmsgstr(p:TObject;arg:pointer);
      var
        i  : longint;
        pd : Tprocdef;
        pt : pprocdeftree;
      begin
        if tsym(p).typ<>procsym then
          exit;
        for i:=0 to Tprocsym(p).ProcdefList.Count-1 do
          begin
            pd:=tprocdef(Tprocsym(p).ProcdefList[i]);
            if po_msgstr in pd.procoptions then
              begin
                new(pt);
                pt^.data:=pd;
                pt^.l:=nil;
                pt^.r:=nil;
                insertstr(pt,root,plongint(arg)^);
              end;
          end;
      end;


    procedure TVMTWriter.writenames(p : pprocdeftree);
      var
        ca : pchar;
        len : byte;
      begin
         current_asmdata.getdatalabel(p^.nl);
         if assigned(p^.l) then
           writenames(p^.l);
         current_asmdata.asmlists[al_globals].concat(cai_align.create(const_align(sizeof(aint))));
         current_asmdata.asmlists[al_globals].concat(Tai_label.Create(p^.nl));
         len:=length(p^.data.messageinf.str^);
         current_asmdata.asmlists[al_globals].concat(tai_const.create_8bit(len));
         getmem(ca,len+1);
         move(p^.data.messageinf.str[1],ca^,len);
         ca[len]:=#0;
         current_asmdata.asmlists[al_globals].concat(Tai_string.Create_pchar(ca,len));
         if assigned(p^.r) then
           writenames(p^.r);
      end;

    procedure TVMTWriter.writestrentry(p : pprocdeftree);

      begin
         if assigned(p^.l) then
           writestrentry(p^.l);

         { write name label }
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(p^.nl));
         current_asmdata.asmlists[al_globals].concat(Tai_const.Createname(p^.data.mangledname,0));

         if assigned(p^.r) then
           writestrentry(p^.r);
     end;


    function TVMTWriter.genstrmsgtab : tasmlabel;
      var
         count : aint;
      begin
         root:=nil;
         count:=0;
         { insert all message handlers into a tree, sorted by name }
         _class.symtable.SymList.ForEachCall(@insertmsgstr,@count);

         { write all names }
         if assigned(root) then
           writenames(root);

         { now start writing of the message string table }
         current_asmdata.getdatalabel(result);
         current_asmdata.asmlists[al_globals].concat(cai_align.create(const_align(sizeof(aint))));
         current_asmdata.asmlists[al_globals].concat(Tai_label.Create(result));
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create_aint(count));
         if assigned(root) then
           begin
              writestrentry(root);
              disposeprocdeftree(root);
           end;
      end;


    procedure TVMTWriter.writeintentry(p : pprocdeftree);
      begin
         if assigned(p^.l) then
           writeintentry(p^.l);

         { write name label }
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create_32bit(p^.data.messageinf.i));
         current_asmdata.asmlists[al_globals].concat(Tai_const.Createname(p^.data.mangledname,0));

         if assigned(p^.r) then
           writeintentry(p^.r);
      end;


    function TVMTWriter.genintmsgtab : tasmlabel;
      var
         r : tasmlabel;
         count : longint;
      begin
         root:=nil;
         count:=0;
         { insert all message handlers into a tree, sorted by name }
         _class.symtable.SymList.ForEachCall(@insertmsgint,@count);

         { now start writing of the message string table }
         current_asmdata.getdatalabel(r);
         current_asmdata.asmlists[al_globals].concat(cai_align.create(const_align(sizeof(aint))));
         current_asmdata.asmlists[al_globals].concat(Tai_label.Create(r));
         genintmsgtab:=r;
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create_32bit(count));
         if assigned(root) then
           begin
              writeintentry(root);
              disposeprocdeftree(root);
           end;
      end;

{$ifdef WITHDMT}

{**************************************
              DMT
**************************************}

    procedure TVMTWriter.insertdmtentry(p:TObject;arg:pointer);

      var
         hp : tprocdef;
         pt : pprocdeftree;

      begin
         if tsym(p).typ=procsym then
           begin
              hp:=tprocsym(p).definition;
              while assigned(hp) do
                begin
                   if (po_msgint in hp.procoptions) then
                     begin
                        new(pt);
                        pt^.p:=hp;
                        pt^.l:=nil;
                        pt^.r:=nil;
                        insertint(pt,root);
                     end;
                   hp:=hp.nextoverloaded;
                end;
           end;
      end;

    procedure TVMTWriter.writedmtindexentry(p : pprocdeftree);

      begin
         if assigned(p^.l) then
           writedmtindexentry(p^.l);
         al_globals.concat(Tai_const.Create_32bit(p^.data.messageinf.i));
         if assigned(p^.r) then
           writedmtindexentry(p^.r);
      end;

    procedure TVMTWriter.writedmtaddressentry(p : pprocdeftree);

      begin
         if assigned(p^.l) then
           writedmtaddressentry(p^.l);
         al_globals.concat(Tai_const_symbol.Createname(p^.data.mangledname,0));
         if assigned(p^.r) then
           writedmtaddressentry(p^.r);
      end;

    function TVMTWriter.gendmt : tasmlabel;

      var
         r : tasmlabel;

      begin
         root:=nil;
         count:=0;
         gendmt:=nil;
         { insert all message handlers into a tree, sorted by number }
         _class.symtable.SymList.ForEachCall(insertdmtentry);

         if count>0 then
           begin
              current_asmdata.getdatalabel(r);
              gendmt:=r;
              al_globals.concat(cai_align.create(const_align(sizeof(aint))));
              al_globals.concat(Tai_label.Create(r));
              { entries for caching }
              al_globals.concat(Tai_const.Create_ptr(0));
              al_globals.concat(Tai_const.Create_ptr(0));

              al_globals.concat(Tai_const.Create_32bit(count));
              if assigned(root) then
                begin
                   writedmtindexentry(root);
                   writedmtaddressentry(root);
                   disposeprocdeftree(root);
                end;
           end;
      end;

{$endif WITHDMT}

{**************************************
        Published Methods
**************************************}

    procedure TVMTWriter.do_count_published_methods(p:TObject;arg:pointer);
      var
        i  : longint;
        pd : tprocdef;
      begin
        if (tsym(p).typ<>procsym) then
          exit;
        for i:=0 to Tprocsym(p).ProcdefList.Count-1 do
          begin
            pd:=tprocdef(Tprocsym(p).ProcdefList[i]);
            if (pd.procsym=tsym(p)) and
               (sp_published in pd.symoptions) then
              inc(plongint(arg)^);
          end;
      end;


    procedure TVMTWriter.do_gen_published_methods(p:TObject;arg:pointer);
      var
        i  : longint;
        l  : tasmlabel;
        pd : tprocdef;
      begin
        if (tsym(p).typ<>procsym) then
          exit;
        for i:=0 to Tprocsym(p).ProcdefList.Count-1 do
          begin
            pd:=tprocdef(Tprocsym(p).ProcdefList[i]);
            if (pd.procsym=tsym(p)) and
               (sp_published in pd.symoptions) then
              begin
                current_asmdata.getdatalabel(l);

                current_asmdata.asmlists[al_typedconsts].concat(cai_align.create(const_align(sizeof(aint))));
                current_asmdata.asmlists[al_typedconsts].concat(Tai_label.Create(l));
                current_asmdata.asmlists[al_typedconsts].concat(Tai_const.Create_8bit(length(tsym(p).realname)));
                current_asmdata.asmlists[al_typedconsts].concat(Tai_string.Create(tsym(p).realname));

                current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(l));
                if po_abstractmethod in pd.procoptions then
                  current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil))
                else
                  current_asmdata.asmlists[al_globals].concat(Tai_const.Createname(pd.mangledname,0));
              end;
           end;
      end;


    function TVMTWriter.genpublishedmethodstable : tasmlabel;

      var
         l : tasmlabel;
         count : longint;

      begin
         count:=0;
         _class.symtable.SymList.ForEachCall(@do_count_published_methods,@count);
         if count>0 then
           begin
              current_asmdata.getdatalabel(l);
              current_asmdata.asmlists[al_globals].concat(cai_align.create(const_align(sizeof(aint))));
              current_asmdata.asmlists[al_globals].concat(Tai_label.Create(l));
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_32bit(count));
              _class.symtable.SymList.ForEachCall(@do_gen_published_methods,nil);
              genpublishedmethodstable:=l;
           end
         else
           genpublishedmethodstable:=nil;
      end;


    function TVMTWriter.generate_field_table : tasmlabel;
      var
        i   : longint;
        sym : tsym;
        fieldtable,
        classtable : tasmlabel;
        classindex,
        fieldcount : longint;
        classtablelist : TFPList;
      begin
        classtablelist:=TFPList.Create;
        current_asmdata.getdatalabel(fieldtable);
        current_asmdata.getdatalabel(classtable);
        maybe_new_object_file(current_asmdata.asmlists[al_rtti]);
        new_section(current_asmdata.asmlists[al_rtti],sec_rodata,classtable.name,const_align(sizeof(aint)));

        { retrieve field info fields }
        fieldcount:=0;
        for i:=0 to _class.symtable.SymList.Count-1 do
          begin
            sym:=tsym(_class.symtable.SymList[i]);
            if (tsym(sym).typ=fieldvarsym) and
               (sp_published in tsym(sym).symoptions) then
             begin
                if tfieldvarsym(sym).vardef.typ<>objectdef then
                  internalerror(200611032);
                classindex:=classtablelist.IndexOf(tfieldvarsym(sym).vardef);
                if classindex=-1 then
                  classtablelist.Add(tfieldvarsym(sym).vardef);
                inc(fieldcount);
             end;
          end;

        { write fields }
        current_asmdata.asmlists[al_rtti].concat(Tai_label.Create(fieldtable));
        current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_16bit(fieldcount));
{$ifdef cpurequiresproperalignment}
        current_asmdata.asmlists[al_rtti].concat(cai_align.Create(sizeof(TConstPtrUInt)));
{$endif cpurequiresproperalignment}
        current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_sym(classtable));
        for i:=0 to _class.symtable.SymList.Count-1 do
          begin
            sym:=tsym(_class.symtable.SymList[i]);
            if (tsym(sym).typ=fieldvarsym) and
               (sp_published in tsym(sym).symoptions) then
              begin
{$ifdef cpurequiresproperalignment}
                current_asmdata.asmlists[al_rtti].concat(cai_align.Create(sizeof(AInt)));
{$endif cpurequiresproperalignment}
                current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_aint(tfieldvarsym(sym).fieldoffset));
                classindex:=classtablelist.IndexOf(tfieldvarsym(sym).vardef);
                if classindex=-1 then
                  internalerror(200611033);
                current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_16bit(classindex+1));
                current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_8bit(length(tfieldvarsym(sym).realname)));
                current_asmdata.asmlists[al_rtti].concat(Tai_string.Create(tfieldvarsym(sym).realname));
              end;
          end;

        { generate the class table }
        current_asmdata.asmlists[al_rtti].concat(cai_align.create(const_align(sizeof(aint))));
        current_asmdata.asmlists[al_rtti].concat(Tai_label.Create(classtable));
        current_asmdata.asmlists[al_rtti].concat(Tai_const.Create_16bit(classtablelist.count));
{$ifdef cpurequiresproperalignment}
        current_asmdata.asmlists[al_rtti].concat(cai_align.Create(sizeof(TConstPtrUInt)));
{$endif cpurequiresproperalignment}
        for i:=0 to classtablelist.Count-1 do
          current_asmdata.asmlists[al_rtti].concat(Tai_const.Createname(tobjectdef(classtablelist[i]).vmt_mangledname,0));

        classtablelist.free;
        result:=fieldtable;
      end;


{**************************************
           Interface tables
**************************************}

    function  TVMTWriter.intf_get_vtbl_name(AImplIntf:TImplementedInterface): string;
      begin
        result:=make_mangledname('VTBL',_class.owner,_class.objname^+'_$_'+AImplIntf.IntfDef.objname^);
      end;


    procedure TVMTWriter.intf_create_vtbl(rawdata: TAsmList;AImplIntf:TImplementedInterface);
      var
        pd : tprocdef;
        vtblstr,
        hs : string;
        i  : longint;
      begin
        vtblstr:=intf_get_vtbl_name(AImplIntf);
        section_symbol_start(rawdata,vtblstr,AT_DATA,true,sec_data,const_align(sizeof(aint)));
        if assigned(AImplIntf.procdefs) then
          begin
            for i:=0 to AImplIntf.procdefs.count-1 do
              begin
                pd:=tprocdef(AImplIntf.procdefs[i]);
                hs:=make_mangledname('WRPR',_class.owner,_class.objname^+'_$_'+AImplIntf.IntfDef.objname^+'_$_'+
                                     tostr(i)+'_$_'+pd.mangledname);
                { create reference }
                rawdata.concat(Tai_const.Createname(hs,0));
              end;
           end;
        section_symbol_end(rawdata,vtblstr);
      end;


    procedure TVMTWriter.intf_gen_intf_ref(rawdata: TAsmList;AImplIntf:TImplementedInterface);
      var
        iidlabel,
        guidlabel : tasmlabel;
        i: longint;
      begin
        { GUID }
        if AImplIntf.IntfDef.objecttype in [odt_interfacecom] then
          begin
            { label for GUID }
            current_asmdata.getdatalabel(guidlabel);
            rawdata.concat(cai_align.create(const_align(sizeof(aint))));
            rawdata.concat(Tai_label.Create(guidlabel));
            with AImplIntf.IntfDef.iidguid^ do
              begin
                rawdata.concat(Tai_const.Create_32bit(longint(D1)));
                rawdata.concat(Tai_const.Create_16bit(D2));
                rawdata.concat(Tai_const.Create_16bit(D3));
                for i:=Low(D4) to High(D4) do
                  rawdata.concat(Tai_const.Create_8bit(D4[i]));
              end;
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(guidlabel));
          end
        else
          begin
            { nil for Corba interfaces }
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
          end;
        { VTable }
        current_asmdata.asmlists[al_globals].concat(Tai_const.Createname(intf_get_vtbl_name(AImplIntf.VtblImplIntf),0));
        { IOffset field }
        current_asmdata.asmlists[al_globals].concat(Tai_const.Create_aint(AImplIntf.VtblImplIntf.ioffset));
        { IIDStr }
        current_asmdata.getdatalabel(iidlabel);
        rawdata.concat(cai_align.create(const_align(sizeof(aint))));
        rawdata.concat(Tai_label.Create(iidlabel));
        rawdata.concat(Tai_const.Create_8bit(length(AImplIntf.IntfDef.iidstr^)));
        if AImplIntf.IntfDef.objecttype=odt_interfacecom then
          rawdata.concat(Tai_string.Create(upper(AImplIntf.IntfDef.iidstr^)))
        else
          rawdata.concat(Tai_string.Create(AImplIntf.IntfDef.iidstr^));
        current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(iidlabel));
        { EntryType }
        current_asmdata.asmlists[al_globals].concat(Tai_const.Create_aint(aint(AImplIntf.IntfDef.iitype)));
        { EntryOffset }
        current_asmdata.asmlists[al_globals].concat(Tai_const.Create_aint(aint(AImplIntf.IntfDef.iioffset)));
      end;


    function TVMTWriter.intf_write_table:TAsmLabel;
      var
        rawdata  : TAsmList;
        i        : longint;
        ImplIntf : TImplementedInterface;
        intftablelab : tasmlabel;
      begin
        current_asmdata.getdatalabel(intftablelab);
        current_asmdata.asmlists[al_globals].concat(cai_align.create(const_align(sizeof(aint))));
        current_asmdata.asmlists[al_globals].concat(Tai_label.Create(intftablelab));
        current_asmdata.asmlists[al_globals].concat(Tai_const.Create_aint(_class.ImplementedInterfaces.count));
        rawdata:=TAsmList.Create;
        { Write vtbls }
        for i:=0 to _class.ImplementedInterfaces.count-1 do
          begin
            ImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[i]);
            if ImplIntf.VtblImplIntf=ImplIntf then
              intf_create_vtbl(rawdata,ImplIntf);
          end;
        { Write vtbl references }
        for i:=0 to _class.ImplementedInterfaces.count-1 do
          begin
            ImplIntf:=TImplementedInterface(_class.ImplementedInterfaces[i]);
            intf_gen_intf_ref(rawdata,ImplIntf);
          end;
        { Write interface table }
        current_asmdata.asmlists[al_globals].concatlist(rawdata);
        rawdata.free;
        result:=intftablelab;
      end;


  { Write interface identifiers to the data section }
  procedure TVMTWriter.writeinterfaceids;
    var
      i : longint;
      s : string;
    begin
      if assigned(_class.iidguid) then
        begin
          s:=make_mangledname('IID',_class.owner,_class.objname^);
          maybe_new_object_file(current_asmdata.asmlists[al_globals]);
          new_section(current_asmdata.asmlists[al_globals],sec_rodata,s,const_align(sizeof(aint)));
          current_asmdata.asmlists[al_globals].concat(Tai_symbol.Createname_global(s,AT_DATA,0));
          current_asmdata.asmlists[al_globals].concat(Tai_const.Create_32bit(longint(_class.iidguid^.D1)));
          current_asmdata.asmlists[al_globals].concat(Tai_const.Create_16bit(_class.iidguid^.D2));
          current_asmdata.asmlists[al_globals].concat(Tai_const.Create_16bit(_class.iidguid^.D3));
          for i:=Low(_class.iidguid^.D4) to High(_class.iidguid^.D4) do
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_8bit(_class.iidguid^.D4[i]));
        end;
      maybe_new_object_file(current_asmdata.asmlists[al_globals]);
      s:=make_mangledname('IIDSTR',_class.owner,_class.objname^);
      new_section(current_asmdata.asmlists[al_globals],sec_rodata,s,0);
      current_asmdata.asmlists[al_globals].concat(Tai_symbol.Createname_global(s,AT_DATA,0));
      current_asmdata.asmlists[al_globals].concat(Tai_const.Create_8bit(length(_class.iidstr^)));
      current_asmdata.asmlists[al_globals].concat(Tai_string.Create(_class.iidstr^));
    end;


    procedure TVMTWriter.writevirtualmethods(List:TAsmList);
      var
         pd : tprocdef;
         i  : longint;
         procname : string;
{$ifdef vtentry}
         hs : string;
{$endif vtentry}
      begin
        if not assigned(_class.VMTEntries) then
          exit;
        for i:=0 to _class.VMTEntries.Count-1 do
         begin
           pd:=tprocdef(_class.VMTEntries[i]);
           if not(po_virtualmethod in pd.procoptions) then
             internalerror(200611082);
           if pd.extnumber<>i then
             internalerror(200611083);
           if (po_abstractmethod in pd.procoptions) then
             procname:='FPC_ABSTRACTERROR'
           else
             procname:=pd.mangledname;
           List.concat(Tai_const.createname(procname,0));
{$ifdef vtentry}
           hs:='VTENTRY'+'_'+_class.vmt_mangledname+'$$'+tostr(_class.vmtmethodoffset(i) div sizeof(aint));
           current_asmdata.asmlists[al_globals].concat(tai_symbol.CreateName(hs,AT_DATA,0));
{$endif vtentry}
         end;
        { release VMTEntries, we don't need them anymore }
        _class.VMTEntries.free;
        _class.VMTEntries:=nil;
      end;


    procedure TVMTWriter.writevmt;
      var
         methodnametable,intmessagetable,
         strmessagetable,classnamelabel,
         fieldtablelabel : tasmlabel;
{$ifdef WITHDMT}
         dmtlabel : tasmlabel;
{$endif WITHDMT}
         interfacetable : tasmlabel;
{$ifdef vtentry}
         hs: string;
{$endif vtentry}
      begin
{$ifdef WITHDMT}
         dmtlabel:=gendmt;
{$endif WITHDMT}

         { write tables for classes, this must be done before the actual
           class is written, because we need the labels defined }
         if is_class(_class) then
          begin
            current_asmdata.getdatalabel(classnamelabel);
            maybe_new_object_file(current_asmdata.asmlists[al_globals]);
            new_section(current_asmdata.asmlists[al_globals],sec_rodata,classnamelabel.name,const_align(sizeof(aint)));

            { interface table }
            if _class.ImplementedInterfaces.count>0 then
              interfacetable:=intf_write_table;

            methodnametable:=genpublishedmethodstable;
            fieldtablelabel:=generate_field_table;
            { write class name }
            current_asmdata.asmlists[al_globals].concat(Tai_label.Create(classnamelabel));
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_8bit(length(_class.objrealname^)));
            current_asmdata.asmlists[al_globals].concat(Tai_string.Create(_class.objrealname^));

            { generate message and dynamic tables }
            if (oo_has_msgstr in _class.objectoptions) then
              strmessagetable:=genstrmsgtab;
            if (oo_has_msgint in _class.objectoptions) then
              intmessagetable:=genintmsgtab;
          end;

        { write debug info }
        maybe_new_object_file(current_asmdata.asmlists[al_globals]);
        new_section(current_asmdata.asmlists[al_globals],sec_rodata,_class.vmt_mangledname,const_align(sizeof(aint)));
        current_asmdata.asmlists[al_globals].concat(Tai_symbol.Createname_global(_class.vmt_mangledname,AT_DATA,0));

         { determine the size with symtable.datasize, because }
         { size gives back 4 for classes                    }
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create(aitconst_ptr,tObjectSymtable(_class.symtable).datasize));
         current_asmdata.asmlists[al_globals].concat(Tai_const.Create(aitconst_ptr,-int64(tObjectSymtable(_class.symtable).datasize)));
{$ifdef WITHDMT}
         if _class.classtype=ct_object then
           begin
              if assigned(dmtlabel) then
                current_asmdata.asmlists[al_globals].concat(Tai_const_symbol.Create(dmtlabel)))
              else
                current_asmdata.asmlists[al_globals].concat(Tai_const.Create_ptr(0));
           end;
{$endif WITHDMT}
         { write pointer to parent VMT, this isn't implemented in TP }
         { but this is not used in FPC ? (PM) }
         { it's not used yet, but the delphi-operators as and is need it (FK) }
         { it is not written for parents that don't have any vmt !! }
         if assigned(_class.childof) and
            (oo_has_vmt in _class.childof.objectoptions) then
           current_asmdata.asmlists[al_globals].concat(Tai_const.Createname(_class.childof.vmt_mangledname,0))
         else
           current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));

         { write extended info for classes, for the order see rtl/inc/objpash.inc }
         if is_class(_class) then
          begin
            { pointer to class name string }
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(classnamelabel));
            { pointer to dynamic table or nil }
            if (oo_has_msgint in _class.objectoptions) then
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(intmessagetable))
            else
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
            { pointer to method table or nil }
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(methodnametable));
            { pointer to field table }
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(fieldtablelabel));
            { pointer to type info of published section }
            if (oo_can_have_published in _class.objectoptions) then
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(RTTIWriter.get_rtti_label(_class,fullrtti)))
            else
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
            { inittable for con-/destruction }
            if _class.members_need_inittable then
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(RTTIWriter.get_rtti_label(_class,initrtti)))
            else
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
            { auto table }
            current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
            { interface table }
            if _class.ImplementedInterfaces.count>0 then
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(interfacetable))
            else
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
            { table for string messages }
            if (oo_has_msgstr in _class.objectoptions) then
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(strmessagetable))
            else
              current_asmdata.asmlists[al_globals].concat(Tai_const.Create_sym(nil));
          end;
         { write virtual methods }
         writevirtualmethods(current_asmdata.asmlists[al_globals]);
         current_asmdata.asmlists[al_globals].concat(Tai_const.create(aitconst_ptr,0));
         { write the size of the VMT }
         current_asmdata.asmlists[al_globals].concat(Tai_symbol_end.Createname(_class.vmt_mangledname));
{$ifdef vtentry}
         { write vtinherit symbol to notify the linker of the class inheritance tree }
         hs:='VTINHERIT'+'_'+_class.vmt_mangledname+'$$';
         if assigned(_class.childof) then
           hs:=hs+_class.childof.vmt_mangledname
         else
           hs:=hs+_class.vmt_mangledname;
         current_asmdata.asmlists[al_globals].concat(tai_symbol.CreateName(hs,AT_DATA,0));
{$endif vtentry}
      end;


end.