freepascal.compiler/compiler/pdecvar.pas

{
    Copyright (c) 1998-2002 by Florian Klaempfl

    Parses variable declarations. Used for var statement and record
    definitions

    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 pdecvar;

{$i fpcdefs.inc}

interface

    uses
      symsym,symdef;

    type
      tvar_dec_option=(vd_record,vd_object,vd_threadvar);
      tvar_dec_options=set of tvar_dec_option;

    function  read_property_dec(aclass:tobjectdef):tpropertysym;

    procedure read_var_decls(options:Tvar_dec_options);

    procedure read_record_fields(options:Tvar_dec_options);


implementation

    uses
       SysUtils,
       { common }
       cutils,cclasses,
       { global }
       globtype,globals,tokens,verbose,
       systems,
       { symtable }
       symconst,symbase,symtype,symtable,defutil,defcmp,
       fmodule,
       { pass 1 }
       node,pass_1,aasmdata,
       nmat,nadd,ncal,nset,ncnv,ninl,ncon,nld,nflw,nmem,
       { codegen }
       ncgutil,
       { parser }
       scanner,
       pbase,pexpr,ptype,ptconst,pdecsub,
       { link }
       import
       ;


    function read_property_dec(aclass:tobjectdef):tpropertysym;

        { convert a node tree to symlist and return the last
          symbol }
        function parse_symlist(pl:tpropaccesslist;var def:tdef):boolean;
          var
            idx : longint;
            sym : tsym;
            srsymtable : TSymtable;
            st  : TSymtable;
            p   : tnode;
          begin
            result:=true;
            def:=nil;
            if token=_ID then
             begin
               if assigned(aclass) then
                 sym:=search_class_member(aclass,pattern)
               else
                 searchsym(pattern,sym,srsymtable);
               if assigned(sym) then
                begin
                  case sym.typ of
                    fieldvarsym :
                      begin
                        if not(sp_private in current_object_option) then
                          addsymref(sym);
                        pl.addsym(sl_load,sym);
                        def:=tfieldvarsym(sym).vardef;
                      end;
                    procsym :
                      begin
                        if not(sp_private in current_object_option) then
                          addsymref(sym);
                        pl.addsym(sl_call,sym);
                      end;
                    else
                      begin
                        Message1(parser_e_illegal_field_or_method,orgpattern);
                        result:=false;
                      end;
                  end;
                end
               else
                begin
                  Message1(parser_e_illegal_field_or_method,orgpattern);
                  result:=false;
                end;
               consume(_ID);
               repeat
                 case token of
                   _ID,
                   _SEMICOLON :
                     begin
                       break;
                     end;
                   _POINT :
                     begin
                       consume(_POINT);
                       if assigned(def) then
                        begin
                          st:=def.GetSymtable(gs_record);
                          if assigned(st) then
                           begin
                             sym:=tsym(st.Find(pattern));
                             if assigned(sym) then
                              begin
                                pl.addsym(sl_subscript,sym);
                                case sym.typ of
                                  fieldvarsym :
                                    def:=tfieldvarsym(sym).vardef;
                                  else
                                    begin
                                      Message1(sym_e_illegal_field,orgpattern);
                                      result:=false;
                                    end;
                                end;
                              end
                             else
                              begin
                                Message1(sym_e_illegal_field,orgpattern);
                                result:=false;
                              end;
                           end
                          else
                           begin
                             Message(parser_e_invalid_qualifier);
                             result:=false;
                           end;
                        end
                       else
                        begin
                          Message(parser_e_invalid_qualifier);
                          result:=false;
                        end;
                       consume(_ID);
                     end;
                   _LECKKLAMMER :
                     begin
                       consume(_LECKKLAMMER);
                       repeat
                         if def.typ=arraydef then
                          begin
                            idx:=0;
                            p:=comp_expr(true);
                            if (not codegenerror) then
                             begin
                               if (p.nodetype=ordconstn) then
                                 begin
                                   if compare_defs(p.resultdef,tarraydef(def).rangedef,nothingn)>=te_equal then
                                     idx:=tordconstnode(p).value
                                   else
                                     IncompatibleTypes(p.resultdef,tarraydef(def).rangedef);
                                 end
                               else
                                Message(type_e_ordinal_expr_expected)
                             end;
                            p.free;
                            pl.addconst(sl_vec,idx,p.resultdef);
                            def:=tarraydef(def).elementdef;
                          end
                         else
                          begin
                            Message(parser_e_invalid_qualifier);
                            result:=false;
                          end;
                       until not try_to_consume(_COMMA);
                       consume(_RECKKLAMMER);
                     end;
                   else
                     begin
                       Message(parser_e_ill_property_access_sym);
                       result:=false;
                       break;
                     end;
                 end;
               until false;
             end
            else
             begin
               Message(parser_e_ill_property_access_sym);
               result:=false;
             end;
          end;

      var
         sym : tsym;
         p : tpropertysym;
         overriden : tsym;
         varspez : tvarspez;
         hdef : tdef;
         arraytype : tdef;
         def : tdef;
         pt : tnode;
         sc : TFPObjectList;
         paranr : word;
         i      : longint;
         ImplIntf     : TImplementedInterface;
         found        : boolean;
         hreadparavs,
         hparavs      : tparavarsym;
         storedprocdef,
         readprocdef,
         writeprocdef : tprocvardef;
      begin
         { Generate temp procvardefs to search for matching read/write
           procedures. the readprocdef will store all definitions }
         paranr:=0;
         readprocdef:=tprocvardef.create(normal_function_level);
         writeprocdef:=tprocvardef.create(normal_function_level);
         storedprocdef:=tprocvardef.create(normal_function_level);

         { make it method pointers }
         if assigned(aclass) then
           begin
             include(readprocdef.procoptions,po_methodpointer);
             include(writeprocdef.procoptions,po_methodpointer);
             include(storedprocdef.procoptions,po_methodpointer);
           end;

         { method for stored must return boolean }
         storedprocdef.returndef:=booltype;

         if token<>_ID then
           begin
              consume(_ID);
              consume(_SEMICOLON);
              exit;
           end;
         { Generate propertysym and insert in symtablestack }
         p:=tpropertysym.create(orgpattern);
         symtablestack.top.insert(p);
         consume(_ID);
         { property parameters ? }
         if try_to_consume(_LECKKLAMMER) then
           begin
              if (sp_published in current_object_option) and
                not (m_delphi in current_settings.modeswitches) then
                Message(parser_e_cant_publish_that_property);
              { create a list of the parameters }
              symtablestack.push(readprocdef.parast);
              sc:=TFPObjectList.create(false);
              inc(testcurobject);
              repeat
                if try_to_consume(_VAR) then
                  varspez:=vs_var
                else if try_to_consume(_CONST) then
                  varspez:=vs_const
                else if (m_out in current_settings.modeswitches) and try_to_consume(_OUT) then
                  varspez:=vs_out
                else
                  varspez:=vs_value;
                sc.clear;
                repeat
                  inc(paranr);
                  hreadparavs:=tparavarsym.create(orgpattern,10*paranr,varspez,generrordef,[]);
                  readprocdef.parast.insert(hreadparavs);
                  sc.add(hreadparavs);
                  consume(_ID);
                until not try_to_consume(_COMMA);
                if try_to_consume(_COLON) then
                  begin
                    if try_to_consume(_ARRAY) then
                      begin
                        consume(_OF);
                        { define range and type of range }
                        hdef:=tarraydef.create(0,-1,s32inttype);
                        { define field type }
                        single_type(arraytype,false);
                        tarraydef(hdef).elementdef:=arraytype;
                      end
                    else
                      single_type(hdef,false);
                  end
                else
                  hdef:=cformaltype;
                for i:=0 to sc.count-1 do
                  begin
                    hreadparavs:=tparavarsym(sc[i]);
                    hreadparavs.vardef:=hdef;
                    { also update the writeprocdef }
                    hparavs:=tparavarsym.create(hreadparavs.realname,hreadparavs.paranr,vs_value,hdef,[]);
                    writeprocdef.parast.insert(hparavs);
                  end;
              until not try_to_consume(_SEMICOLON);
              sc.free;
              dec(testcurobject);
              symtablestack.pop(readprocdef.parast);
              consume(_RECKKLAMMER);

              { the parser need to know if a property has parameters, the
                index parameter doesn't count (PFV) }
              if paranr>0 then
                include(p.propoptions,ppo_hasparameters);
           end;
         { overriden property ?                                 }
         { force property interface
             there is a property parameter
             a global property }
         if (token=_COLON) or (paranr>0) or (aclass=nil) then
           begin
              consume(_COLON);
              single_type(p.propdef,false);
              if (idtoken=_INDEX) then
                begin
                   consume(_INDEX);
                   pt:=comp_expr(true);
                   { Only allow enum and integer indexes. Convert all integer
                     values to s32int to be compatible with delphi, because the
                     procedure matching requires equal parameters }
                   if is_constnode(pt) and
                      is_ordinal(pt.resultdef)
{$ifndef cpu64bit}
                      and (not is_64bitint(pt.resultdef))
{$endif cpu64bit}
                      then
                     begin
                       if is_integer(pt.resultdef) then
                         inserttypeconv_internal(pt,s32inttype);
                       p.index:=tordconstnode(pt).value;
                     end
                   else
                     begin
                       Message(parser_e_invalid_property_index_value);
                       p.index:=0;
                     end;
                   p.indexdef:=pt.resultdef;
                   include(p.propoptions,ppo_indexed);
                   { concat a longint to the para templates }
                   inc(paranr);
                   hparavs:=tparavarsym.create('$index',10*paranr,vs_value,p.indexdef,[]);
                   readprocdef.parast.insert(hparavs);
                   hparavs:=tparavarsym.create('$index',10*paranr,vs_value,p.indexdef,[]);
                   writeprocdef.parast.insert(hparavs);
                   hparavs:=tparavarsym.create('$index',10*paranr,vs_value,p.indexdef,[]);
                   storedprocdef.parast.insert(hparavs);
                   pt.free;
                end;
           end
         else
           begin
              { do an property override }
              overriden:=search_class_member(aclass.childof,p.name);
              if assigned(overriden) and
                 (overriden.typ=propertysym) and
                 not(is_dispinterface(aclass)) then
                begin
                  p.overridenpropsym:=tpropertysym(overriden);
                  { inherit all type related entries }
                  p.indexdef:=tpropertysym(overriden).indexdef;
                  p.propdef:=tpropertysym(overriden).propdef;
                  p.index:=tpropertysym(overriden).index;
                  p.default:=tpropertysym(overriden).default;
                  p.propoptions:=tpropertysym(overriden).propoptions;
                end
              else
                begin
                  p.propdef:=generrordef;
                  message(parser_e_no_property_found_to_override);
                end;
           end;
         if ((sp_published in current_object_option) or is_dispinterface(aclass)) and
            not(p.propdef.is_publishable) then
           Message(parser_e_cant_publish_that_property);

         if not(is_dispinterface(aclass)) then
           begin
             if try_to_consume(_READ) then
               begin
                 p.propaccesslist[palt_read].clear;
                 if parse_symlist(p.propaccesslist[palt_read],def) then
                  begin
                    sym:=p.propaccesslist[palt_read].firstsym^.sym;
                    case sym.typ of
                      procsym :
                        begin
                          { read is function returning the type of the property }
                          readprocdef.returndef:=p.propdef;
                          { Insert hidden parameters }
                          handle_calling_convention(readprocdef);
                          { search procdefs matching readprocdef }
                          { we ignore hidden stuff here because the property access symbol might have
                            non default calling conventions which might change the hidden stuff;
                            see tw3216.pp (FK) }
                          p.propaccesslist[palt_read].procdef:=Tprocsym(sym).Find_procdef_bypara(readprocdef.paras,p.propdef,[cpo_allowdefaults,cpo_ignorehidden]);
                          if not assigned(p.propaccesslist[palt_read].procdef) then
                            Message(parser_e_ill_property_access_sym);
                        end;
                      fieldvarsym :
                        begin
                          if not assigned(def) then
                            internalerror(200310071);
                          if compare_defs(def,p.propdef,nothingn)>=te_equal then
                           begin
                             { property parameters are allowed if this is
                               an indexed property, because the index is then
                               the parameter.
                               Note: In the help of Kylix it is written
                               that it isn't allowed, but the compiler accepts it (PFV) }
                             if (ppo_hasparameters in p.propoptions) then
                              Message(parser_e_ill_property_access_sym);
                           end
                          else
                           IncompatibleTypes(def,p.propdef);
                        end;
                      else
                        Message(parser_e_ill_property_access_sym);
                    end;
                  end;
               end;
             if try_to_consume(_WRITE) then
               begin
                 p.propaccesslist[palt_write].clear;
                 if parse_symlist(p.propaccesslist[palt_write],def) then
                  begin
                    sym:=p.propaccesslist[palt_write].firstsym^.sym;
                    case sym.typ of
                      procsym :
                        begin
                          { write is a procedure with an extra value parameter
                            of the of the property }
                          writeprocdef.returndef:=voidtype;
                          inc(paranr);
                          hparavs:=tparavarsym.create('$value',10*paranr,vs_value,p.propdef,[]);
                          writeprocdef.parast.insert(hparavs);
                          { Insert hidden parameters }
                          handle_calling_convention(writeprocdef);
                          { search procdefs matching writeprocdef }
                          p.propaccesslist[palt_write].procdef:=Tprocsym(sym).Find_procdef_bypara(writeprocdef.paras,writeprocdef.returndef,[cpo_allowdefaults]);
                          if not assigned(p.propaccesslist[palt_write].procdef) then
                            Message(parser_e_ill_property_access_sym);
                        end;
                      fieldvarsym :
                        begin
                          if not assigned(def) then
                            internalerror(200310072);
                          if compare_defs(def,p.propdef,nothingn)>=te_equal then
                           begin
                             { property parameters are allowed if this is
                               an indexed property, because the index is then
                               the parameter.
                               Note: In the help of Kylix it is written
                               that it isn't allowed, but the compiler accepts it (PFV) }
                             if (ppo_hasparameters in p.propoptions) then
                              Message(parser_e_ill_property_access_sym);
                           end
                          else
                           IncompatibleTypes(def,p.propdef);
                        end;
                      else
                        Message(parser_e_ill_property_access_sym);
                    end;
                  end;
               end;
           end
         else
           begin
             if try_to_consume(_READONLY) then
               begin
               end
             else if try_to_consume(_WRITEONLY) then
               begin
               end;
             if try_to_consume(_DISPID) then
               begin
                 pt:=comp_expr(true);
                 if is_constintnode(pt) then
                   // tprocdef(pd).extnumber:=tordconstnode(pt).value
                 else
                   Message(parser_e_dispid_must_be_ord_const);
                 pt.free;
               end;
           end;

         if assigned(aclass) and not(is_dispinterface(aclass)) then
           begin
             { ppo_stored is default on for not overriden properties }
             if not assigned(p.overridenpropsym) then
               include(p.propoptions,ppo_stored);
             if try_to_consume(_STORED) then
              begin
                include(p.propoptions,ppo_stored);
                p.propaccesslist[palt_stored].clear;
                case token of
                  _ID:
                    begin
                      { in the case that idtoken=_DEFAULT }
                      { we have to do nothing except      }
                      { setting ppo_stored, it's the same }
                      { as stored true                    }
                      if idtoken<>_DEFAULT then
                       begin
                         if parse_symlist(p.propaccesslist[palt_stored],def) then
                          begin
                            sym:=p.propaccesslist[palt_stored].firstsym^.sym;
                            case sym.typ of
                              procsym :
                                begin
                                   { Insert hidden parameters }
                                   handle_calling_convention(storedprocdef);
                                   p.propaccesslist[palt_stored].procdef:=Tprocsym(sym).Find_procdef_bypara(storedprocdef.paras,storedprocdef.returndef,[cpo_allowdefaults,cpo_ignorehidden]);
                                   if not assigned(p.propaccesslist[palt_stored].procdef) then
                                     message(parser_e_ill_property_storage_sym);
                                end;
                              fieldvarsym :
                                begin
                                  if not assigned(def) then
                                    internalerror(200310073);
                                  if (ppo_hasparameters in p.propoptions) or
                                     not(is_boolean(def)) then
                                   Message(parser_e_stored_property_must_be_boolean);
                                end;
                              else
                                Message(parser_e_ill_property_access_sym);
                            end;
                          end;
                       end;
                    end;
                  _FALSE:
                    begin
                      consume(_FALSE);
                      exclude(p.propoptions,ppo_stored);
                    end;
                  _TRUE:
                    begin
                      p.default:=longint($80000000);
                      consume(_TRUE);
                    end;
                end;
              end;
           end;
         if try_to_consume(_DEFAULT) then
           begin
              if not(is_ordinal(p.propdef) or
{$ifndef cpu64bit}
                     is_64bitint(p.propdef) or
{$endif cpu64bit}
                     is_class(p.propdef) or
                     is_single(p.propdef) or
                     (p.propdef.typ in [classrefdef,pointerdef]) or
                     ((p.propdef.typ=setdef) and
                      (tsetdef(p.propdef).settype=smallset))) or
                     ((p.propdef.typ=arraydef) and
                      (ppo_indexed in p.propoptions)) or
                 (ppo_hasparameters in p.propoptions) then
                begin
                  Message(parser_e_property_cant_have_a_default_value);
                  { Error recovery }
                  pt:=comp_expr(true);
                  pt.free;
                end
              else
                begin
                  { Get the result of the default, the firstpass is
                    needed to support values like -1 }
                  pt:=comp_expr(true);
                  if (p.propdef.typ=setdef) and
                     (pt.nodetype=arrayconstructorn) then
                    begin
                      arrayconstructor_to_set(pt);
                      do_typecheckpass(pt);
                    end;
                  inserttypeconv(pt,p.propdef);
                  if not(is_constnode(pt)) then
                    Message(parser_e_property_default_value_must_const);
                  { Set default value }
                  case pt.nodetype of
                    setconstn :
                      p.default:=plongint(tsetconstnode(pt).value_set)^;
                    ordconstn :
                      p.default:=longint(tordconstnode(pt).value);
                    niln :
                      p.default:=0;
                    realconstn:
                      p.default:=longint(single(trealconstnode(pt).value_real));
                  end;
                  pt.free;
                end;
           end
         else if try_to_consume(_NODEFAULT) then
           begin
              p.default:=longint($80000000);
           end;
         { Parse possible "implements" keyword }
         if try_to_consume(_IMPLEMENTS) then
           begin
             consume(_ID);
             try
               { NOTE: This code will be fixed when the strings are added to the localized string table }
               if not is_interface(p.propdef) then
               begin
                 Comment(V_Error, 'Implements property must have interface type');
                 exit;
               end;
               if pattern <> p.propdef.mangledparaname() then
               begin
                 Comment(V_Error, 'Implements-property must implement interface of correct type');
                 exit;
               end;
               if not assigned(p.propaccesslist[palt_read].firstsym) then
               begin
                 Comment(V_Error, 'Implements-property must have read specifier');
                 exit;
               end;
               if assigned(p.propaccesslist[palt_write].firstsym) then
               begin
                 Comment(V_Error, 'Implements-property must not have write-specifier');
                 exit;
               end;
               if assigned(p.propaccesslist[palt_stored].firstsym) then
               begin
                 Comment(V_Error, 'Implements-property must not have stored-specifier');
                 exit;
               end;
               found:=false;
               for i:=0 to aclass.ImplementedInterfaces.Count-1 do
               begin
                 ImplIntf:=TImplementedInterface(aclass.ImplementedInterfaces[i]);
                 { FIXME: Is this check valid? }
                 if ImplIntf.IntfDef.Objname^=pattern then
                 begin
                   found:=true;
                   break;
                 end;
               end;
               if found then
               begin
                 ImplIntf.IType := etFieldValue;
                 ImplIntf.FieldOffset := tfieldvarsym(p.propaccesslist[palt_read].firstsym^.sym).fieldoffset;
               end
               else
                 Comment(V_Error, 'Implements-property used on unimplemented interface');
             finally
             end;
         end;

         { remove temporary procvardefs }
         readprocdef.owner.deletedef(readprocdef);
         writeprocdef.owner.deletedef(writeprocdef);

         result:=p;
      end;


     function maybe_parse_proc_directives(def:tdef):boolean;
       var
         newtype : ttypesym;
       begin
         result:=false;
         { Process procvar directives before = and ; }
         if (def.typ=procvardef) and
            (def.typesym=nil) and
            check_proc_directive(true) then
           begin
              newtype:=ttypesym.create('unnamed',def);
              parse_var_proc_directives(tsym(newtype));
              newtype.typedef:=nil;
              def.typesym:=nil;
              newtype.free;
              result:=true;
           end;
       end;


    const
       variantrecordlevel : longint = 0;

    procedure read_var_decls(options:Tvar_dec_options);

        procedure read_default_value(sc : TFPObjectList);
        var
          vs : tabstractnormalvarsym;
          tcsym : tstaticvarsym;
        begin
          vs:=tabstractnormalvarsym(sc[0]);
          if sc.count>1 then
            Message(parser_e_initialized_only_one_var);
          if vo_is_thread_var in vs.varoptions then
            Message(parser_e_initialized_not_for_threadvar);
          consume(_EQUAL);
          case vs.typ of
            localvarsym :
              begin
                tcsym:=tstaticvarsym.create('$default'+vs.realname,vs_const,vs.vardef,[]);
                include(tcsym.symoptions,sp_internal);
                vs.defaultconstsym:=tcsym;
                symtablestack.top.insert(tcsym);
                read_typed_const(current_asmdata.asmlists[al_typedconsts],tcsym);
              end;
            staticvarsym :
              begin
                read_typed_const(current_asmdata.asmlists[al_typedconsts],tstaticvarsym(vs));
              end;
            else
              internalerror(200611051);
          end;
          vs.varstate:=vs_initialised;
        end;

{$ifdef gpc_mode}
        procedure read_gpc_name(sc : TFPObjectList);
        var
          vs : tabstractnormalvarsym;
          C_Name : string;
        begin
          consume(_ID);
          C_Name:=get_stringconst;
          vs:=tabstractnormalvarsym(sc[0]);
          if sc.count>1 then
            Message(parser_e_absolute_only_one_var);
          if vs.typ=staticvarsym then
            begin
              tstaticvarsym(vs).set_mangledname(C_Name);
              include(vs.varoptions,vo_is_external);
            end
          else
            Message(parser_e_no_local_var_external);
        end;
{$endif}

        procedure read_absolute(sc : TFPObjectList);
        var
          vs     : tabstractvarsym;
          abssym : tabsolutevarsym;
          pt,hp  : tnode;
          st     : tsymtable;
        begin
          abssym:=nil;
          { only allowed for one var }
          vs:=tabstractvarsym(sc[0]);
          if sc.count>1 then
            Message(parser_e_absolute_only_one_var);
          if vo_is_typed_const in vs.varoptions then
            Message(parser_e_initialized_not_for_external);
          { parse the rest }
          pt:=expr;
          { check allowed absolute types }
          if (pt.nodetype=stringconstn) or
            (is_constcharnode(pt)) then
            begin
              abssym:=tabsolutevarsym.create(vs.realname,vs.vardef);
              abssym.fileinfo:=vs.fileinfo;
              if pt.nodetype=stringconstn then
                abssym.asmname:=stringdup(strpas(tstringconstnode(pt).value_str))
              else
                abssym.asmname:=stringdup(chr(tordconstnode(pt).value));
              consume(token);
              abssym.abstyp:=toasm;
            end
          { address }
          else if is_constintnode(pt) then
            begin
              abssym:=tabsolutevarsym.create(vs.realname,vs.vardef);
              abssym.fileinfo:=vs.fileinfo;
              abssym.abstyp:=toaddr;
              abssym.addroffset:=tordconstnode(pt).value;
{$ifdef i386}
              abssym.absseg:=false;
              if (target_info.system in [system_i386_go32v2,system_i386_watcom]) and
                  try_to_consume(_COLON) then
                begin
                  pt.free;
                  pt:=expr;
                  if is_constintnode(pt) then
                    begin
                      abssym.addroffset:=abssym.addroffset shl 4+tordconstnode(pt).value;
                      abssym.absseg:=true;
                    end
                  else
                    Message(type_e_ordinal_expr_expected);
                end;
{$endif i386}
            end
          { variable }
          else
            begin
              { remove subscriptn before checking for loadn }
              hp:=pt;
              while (hp.nodetype in [subscriptn,typeconvn,vecn]) do
                hp:=tunarynode(hp).left;
              if (hp.nodetype=loadn) then
                begin
                  { we should check the result type of loadn }
                  if not (tloadnode(hp).symtableentry.typ in [fieldvarsym,staticvarsym,localvarsym,paravarsym]) then
                    Message(parser_e_absolute_only_to_var_or_const);
                  abssym:=tabsolutevarsym.create(vs.realname,vs.vardef);
                  abssym.fileinfo:=vs.fileinfo;
                  abssym.abstyp:=tovar;
                  abssym.ref:=node_to_propaccesslist(pt);
                end
              else
                Message(parser_e_absolute_only_to_var_or_const);
            end;
          pt.free;
          { replace old varsym with the new absolutevarsym }
          if assigned(abssym) then
            begin
              st:=vs.owner;
              vs.owner.Delete(vs);
              st.insert(abssym);
              sc[0]:=abssym;
            end;
        end;

        procedure read_public_and_external(sc:TFPObjectList);
        var
          vs          : tabstractvarsym;
          is_dll,
          is_cdecl,
          is_external_var,
          is_public_var  : boolean;
          dll_name,
          C_name      : string;
        begin
          { only allowed for one var }
          vs:=tabstractvarsym(sc[0]);
          if sc.count>1 then
            Message(parser_e_absolute_only_one_var);
          { only allow external and public on global symbols }
          if vs.typ<>staticvarsym then
            begin
              Message(parser_e_no_local_var_external);
              exit;
            end;
          { defaults }
          is_dll:=false;
          is_cdecl:=false;
          is_external_var:=false;
          is_public_var:=false;
          C_name:=vs.realname;

          { macpas specific handling due to some switches}
          if (m_mac in current_settings.modeswitches) then
            begin
              if (cs_external_var in current_settings.localswitches) then
                begin {The effect of this is the same as if cvar; external; has been given as directives.}
                  is_cdecl:=true;
                  is_external_var:=true;
                end
              else if (cs_externally_visible in current_settings.localswitches) then
                begin {The effect of this is the same as if cvar has been given as directives and it's made public.}
                  is_cdecl:=true;
                  is_public_var:=true;
                end;
            end;

          { cdecl }
          if try_to_consume(_CVAR) then
            begin
              consume(_SEMICOLON);
              is_cdecl:=true;
            end;

          { external }
          if try_to_consume(_EXTERNAL) then
            begin
              is_external_var:=true;
              if not is_cdecl then
                begin
                  if idtoken<>_NAME then
                    begin
                      is_dll:=true;
                      dll_name:=get_stringconst;
                      if ExtractFileExt(dll_name)='' then
                        dll_name:=ChangeFileExt(dll_name,target_info.sharedlibext);
                    end;
                  if try_to_consume(_NAME) then
                    C_name:=get_stringconst;
                end;
              consume(_SEMICOLON);
            end;

          { export or public }
          if idtoken in [_EXPORT,_PUBLIC] then
            begin
              consume(_ID);
              if is_external_var then
                Message(parser_e_not_external_and_export)
              else
                is_public_var:=true;
              if try_to_consume(_NAME) then
                C_name:=get_stringconst;
              consume(_SEMICOLON);
            end;

          { Windows uses an indirect reference using import tables }
          if is_dll and
             (target_info.system in system_all_windows) then
            include(vs.varoptions,vo_is_dll_var);

          { Add C _ prefix }
          if is_cdecl or
             (
              is_dll and
              (target_info.system in systems_darwin)
             ) then
            C_Name := target_info.Cprefix+C_Name;

          if is_public_var then
            begin
              include(vs.varoptions,vo_is_public);
              vs.varregable := vr_none;
              { mark as referenced }
              inc(vs.refs);
            end;

          { now we can insert it in the import lib if its a dll, or
            add it to the externals }
          if is_external_var then
            begin
              if vo_is_typed_const in vs.varoptions then
                Message(parser_e_initialized_not_for_external);
              include(vs.varoptions,vo_is_external);
              vs.varregable := vr_none;
              if is_dll then
                current_module.AddExternalImport(dll_name,C_Name,0,true)
              else
                if tf_has_dllscanner in target_info.flags then
                  current_module.dllscannerinputlist.Add(vs.mangledname,vs);
            end;

          { Set the assembler name }
          tstaticvarsym(vs).set_mangledname(C_Name);
        end;

      var
         sc   : TFPObjectList;
         vs   : tabstractvarsym;
         hdef : tdef;
         i    : longint;
         semicoloneaten,
         allowdefaultvalue,
         hasdefaultvalue : boolean;
         old_current_object_option : tsymoptions;
         hintsymoptions  : tsymoptions;
         old_block_type  : tblock_type;
      begin
         old_current_object_option:=current_object_option;
         { all variables are public if not in a object declaration }
         current_object_option:=[sp_public];
         old_block_type:=block_type;
         block_type:=bt_type;
         { Force an expected ID error message }
         if not (token in [_ID,_CASE,_END]) then
           consume(_ID);
         { read vars }
         sc:=TFPObjectList.create(false);
         while (token=_ID) do
           begin
             semicoloneaten:=false;
             hasdefaultvalue:=false;
             allowdefaultvalue:=true;
             sc.clear;
             repeat
               if (token = _ID) then
                 begin
                   case symtablestack.top.symtabletype of
                     localsymtable :
                       vs:=tlocalvarsym.create(orgpattern,vs_value,generrordef,[]);
                     staticsymtable,
                     globalsymtable :
                       begin
                         vs:=tstaticvarsym.create(orgpattern,vs_value,generrordef,[]);
                         if vd_threadvar in options then
                           include(vs.varoptions,vo_is_thread_var);
                       end;
                     else
                       internalerror(200411064);
                   end;
                   sc.add(vs);
                   symtablestack.top.insert(vs);
                 end;
               consume(_ID);
             until not try_to_consume(_COMMA);
             consume(_COLON);

{$ifdef gpc_mode}
             if (m_gpc in current_settings.modeswitches) and
                (token=_ID) and
                (orgpattern='__asmname__') then
               read_gpc_name(sc);
{$endif}

             { read variable type def }
             read_anon_type(hdef,false);
             for i:=0 to sc.count-1 do
               begin
                 vs:=tabstractvarsym(sc[i]);
                 vs.vardef:=hdef;
               end;

             { Process procvar directives }
             if maybe_parse_proc_directives(hdef) then
               semicoloneaten:=true;

             { check for absolute }
             if try_to_consume(_ABSOLUTE) then
               begin
                 read_absolute(sc);
                 allowdefaultvalue:=false;
               end;

             { Check for EXTERNAL etc directives before a semicolon }
             if (idtoken in [_EXPORT,_EXTERNAL,_PUBLIC,_CVAR]) then
               begin
                 read_public_and_external(sc);
                 allowdefaultvalue:=false;
                 semicoloneaten:=true;
               end;

             { try to parse the hint directives }
             hintsymoptions:=[];
             try_consume_hintdirective(hintsymoptions);
             for i:=0 to sc.count-1 do
               begin
                 vs:=tabstractvarsym(sc[i]);
                 vs.symoptions := vs.symoptions + hintsymoptions;
               end;

             { Handling of Delphi typed const = initialized vars }
             if allowdefaultvalue and
                (token=_EQUAL) and
                not(m_tp7 in current_settings.modeswitches) and
                (symtablestack.top.symtabletype<>parasymtable) then
               begin
                 { Add calling convention for procvar }
                 if (hdef.typ=procvardef) and
                    (hdef.typesym=nil) then
                   handle_calling_convention(tprocvardef(hdef));
                 read_default_value(sc);
                 consume(_SEMICOLON);
                 hasdefaultvalue:=true;
               end
             else
               begin
                 if not(semicoloneaten) then
                   consume(_SEMICOLON);
               end;

             { Support calling convention for procvars after semicolon }
             if not(hasdefaultvalue) and
                (hdef.typ=procvardef) and
                (hdef.typesym=nil) then
               begin
                 { Parse procvar directives after ; }
                 maybe_parse_proc_directives(hdef);
                 { Add calling convention for procvar }
                 handle_calling_convention(tprocvardef(hdef));
                 { Handling of Delphi typed const = initialized vars }
                 if (token=_EQUAL) and
                    not(m_tp7 in current_settings.modeswitches) and
                    (symtablestack.top.symtabletype<>parasymtable) then
                   begin
                     read_default_value(sc);
                     consume(_SEMICOLON);
                     hasdefaultvalue:=true;
                   end;
               end;

             { Check for EXTERNAL etc directives or, in macpas, if cs_external_var is set}
             if (
                 (
                  (idtoken in [_EXPORT,_EXTERNAL,_PUBLIC,_CVAR]) and
                  (m_cvar_support in current_settings.modeswitches)
                 ) or
                 (
                  (m_mac in current_settings.modeswitches) and
                  (
                   (cs_external_var in current_settings.localswitches) or
                   (cs_externally_visible in current_settings.localswitches)
                  )
                 )
                ) then
               read_public_and_external(sc);

             { allocate normal variable (non-external and non-typed-const) staticvarsyms }
             for i:=0 to sc.count-1 do
               begin
                 vs:=tabstractvarsym(sc[i]);
                 if (vs.typ=staticvarsym) and
                    not(vo_is_typed_const in vs.varoptions) and
                    not(vo_is_external in vs.varoptions) then
                   insertbssdata(tstaticvarsym(vs));
               end;
           end;
         block_type:=old_block_type;
         current_object_option:=old_current_object_option;
         { free the list }
         sc.free;
      end;


    procedure read_record_fields(options:Tvar_dec_options);
      var
         sc : TFPObjectList;
         i  : longint;
         old_block_type : tblock_type;
         old_current_object_option : tsymoptions;
         hs,sorg : string;
         hdef,casetype : tdef;
         { maxsize contains the max. size of a variant }
         { startvarrec contains the start of the variant part of a record }
         maxsize, startvarrecsize : longint;
         usedalign,
         maxalignment,startvarrecalign,
         maxpadalign, startpadalign: shortint;
         pt : tnode;
         fieldvs   : tfieldvarsym;
         hstaticvs : tstaticvarsym;
         vs    : tabstractvarsym;
         srsym : tsym;
         srsymtable : TSymtable;
         recst : tabstractrecordsymtable;
         unionsymtable : trecordsymtable;
         offset : longint;
         uniondef : trecorddef;
         hintsymoptions : tsymoptions;
         semicoloneaten: boolean;
{$if defined(powerpc) or defined(powerpc64)}
         tempdef: tdef;
         is_first_field: boolean;
{$endif powerpc or powerpc64}
      begin
         recst:=tabstractrecordsymtable(symtablestack.top);
{$if defined(powerpc) or defined(powerpc64)}
         is_first_field := true;
{$endif powerpc or powerpc64}
         old_current_object_option:=current_object_option;
         { all variables are public if not in a object declaration }
         if not(vd_object in options) then
          current_object_option:=[sp_public];
         old_block_type:=block_type;
         block_type:=bt_type;
         { Force an expected ID error message }
         if not (token in [_ID,_CASE,_END]) then
          consume(_ID);
         { read vars }
         sc:=TFPObjectList.create(false);
         while (token=_ID) and
            not((vd_object in options) and
                (idtoken in [_PUBLIC,_PRIVATE,_PUBLISHED,_PROTECTED,_STRICT])) do
           begin
             sorg:=orgpattern;
             semicoloneaten:=false;
             sc.clear;
             repeat
               if try_to_consume(_ID) then
                 begin
                   vs:=tfieldvarsym.create(orgpattern,vs_value,generrordef,[]);
                   sc.add(vs);
                   recst.insert(vs);
                 end;
             until not try_to_consume(_COMMA);
             consume(_COLON);

             { Don't search in the recordsymtable for types }
             if ([df_generic,df_specialization]*tdef(recst.defowner).defoptions=[]) then
               symtablestack.pop(recst);
             read_anon_type(hdef,false);
             if ([df_generic,df_specialization]*tdef(recst.defowner).defoptions=[]) then
               symtablestack.push(recst);

             { Process procvar directives }
             if maybe_parse_proc_directives(hdef) then
               semicoloneaten:=true;

{$if defined(powerpc) or defined(powerpc64)}
             { from gcc/gcc/config/rs6000/rs6000.h:
              /* APPLE LOCAL begin Macintosh alignment 2002-1-22 ff */
              /* Return the alignment of a struct based on the Macintosh PowerPC
                 alignment rules.  In general the alignment of a struct is
                 determined by the greatest alignment of its elements.  However, the
                 PowerPC rules cause the alignment of a struct to peg at word
                 alignment except when the first field has greater than word
                 (32-bit) alignment, in which case the alignment is determined by
                 the alignment of the first field.  */
             }
             if (target_info.system in [system_powerpc_darwin, system_powerpc_macos, system_powerpc64_darwin]) and
                is_first_field and
                (symtablestack.top.symtabletype = recordsymtable) and
                (trecordsymtable(symtablestack.top).usefieldalignment = -1) then
               begin
                 tempdef := hdef;
                 while tempdef.typ = arraydef do
                   tempdef := tarraydef(tempdef).elementdef;
                 if tempdef.typ <> recorddef then
                   maxpadalign := tempdef.alignment
                 else
                   maxpadalign := trecorddef(tempdef).padalignment;

                 if (maxpadalign > 4) and
                    (maxpadalign > trecordsymtable(symtablestack.top).padalignment) then
                   trecordsymtable(symtablestack.top).padalignment := maxpadalign;
                 is_first_field := false;
               end;
{$endif powerpc or powerpc64}

             { types that use init/final are not allowed in variant parts, but
               classes are allowed }
             if (variantrecordlevel>0) and
                (hdef.needs_inittable and not is_class(hdef)) then
               Message(parser_e_cant_use_inittable_here);

             { try to parse the hint directives }
             hintsymoptions:=[];
             try_consume_hintdirective(hintsymoptions);

             { update variable type and hints }
             for i:=0 to sc.count-1 do
               begin
                 fieldvs:=tfieldvarsym(sc[i]);
                 fieldvs.vardef:=hdef;
                 { insert any additional hint directives }
                 fieldvs.symoptions := fieldvs.symoptions + hintsymoptions;
               end;

             { Records and objects can't have default values }
             { for a record there doesn't need to be a ; before the END or )    }
             if not(token in [_END,_RKLAMMER]) and
                not(semicoloneaten) then
               consume(_SEMICOLON);

             { Parse procvar directives after ; }
             maybe_parse_proc_directives(hdef);

             { Add calling convention for procvar }
             if (hdef.typ=procvardef) and
                (hdef.typesym=nil) then
               handle_calling_convention(tprocvardef(hdef));

             { Check for STATIC directive }
             if (vd_object in options) and
                (cs_static_keyword in current_settings.moduleswitches) and
                (try_to_consume(_STATIC)) then
               begin
                 { add static flag and staticvarsyms }
                 for i:=0 to sc.count-1 do
                   begin
                     fieldvs:=tfieldvarsym(sc[i]);
                     include(fieldvs.symoptions,sp_static);
                     hstaticvs:=tstaticvarsym.create('$'+lower(symtablestack.top.name^)+'_'+fieldvs.name,vs_value,hdef,[]);
                     recst.defowner.owner.insert(hstaticvs);
                     insertbssdata(hstaticvs);
                   end;
                 consume(_SEMICOLON);
               end;

             if (sp_published in current_object_option) and
                not(is_class(hdef)) then
               begin
                 Message(parser_e_cant_publish_that);
                 exclude(current_object_option,sp_published);
                 { recover by changing access type to public }
                 for i:=0 to sc.count-1 do
                   begin
                     fieldvs:=tfieldvarsym(sc[i]);
                     exclude(fieldvs.symoptions,sp_published);
                     include(fieldvs.symoptions,sp_public);
                   end;
               end
             else
              if (sp_published in current_object_option) and
                 not(oo_can_have_published in tobjectdef(hdef).objectoptions) then
               begin
                 Message(parser_e_only_publishable_classes_can__be_published);
                 exclude(current_object_option,sp_published);
               end;

             { Generate field in the recordsymtable }
             for i:=0 to sc.count-1 do
               begin
                 fieldvs:=tfieldvarsym(sc[i]);
                 { static data fields are already inserted in the globalsymtable }
                 if not(sp_static in current_object_option) then
                   recst.addfield(fieldvs);
               end;

             { restore current_object_option, it can be changed for
               publishing or static }
             current_object_option:=old_current_object_option;
           end;

         { Check for Case }
         if (vd_record in options) and
            try_to_consume(_CASE) then
           begin
              maxsize:=0;
              maxalignment:=0;
              maxpadalign:=0;
              { including a field declaration? }
              fieldvs:=nil;
              sorg:=orgpattern;
              hs:=pattern;
              searchsym(hs,srsym,srsymtable);
              if not(assigned(srsym) and (srsym.typ in [typesym,unitsym])) then
                begin
                  consume(_ID);
                  consume(_COLON);
                  fieldvs:=tfieldvarsym.create(sorg,vs_value,generrordef,[]);
                  symtablestack.top.insert(fieldvs);
                end;
              read_anon_type(casetype,true);
              if assigned(fieldvs) then
                begin
                  fieldvs.vardef:=casetype;
                  recst.addfield(fieldvs);
                end;
              if not(is_ordinal(casetype))
{$ifndef cpu64bit}
                 or is_64bitint(casetype)
{$endif cpu64bit}
                 then
                Message(type_e_ordinal_expr_expected);
              consume(_OF);

              UnionSymtable:=trecordsymtable.create(current_settings.packrecords);
              UnionDef:=trecorddef.create(unionsymtable);
              uniondef.isunion:=true;
              startvarrecsize:=UnionSymtable.datasize;
              { align the bitpacking to the next byte }
              UnionSymtable.datasize:=startvarrecsize;
              startvarrecalign:=UnionSymtable.fieldalignment;
              startpadalign:=Unionsymtable.padalignment;
              symtablestack.push(UnionSymtable);
              repeat
                repeat
                  pt:=comp_expr(true);
                  if not(pt.nodetype=ordconstn) then
                    Message(parser_e_illegal_expression);
                  if try_to_consume(_POINTPOINT) then
                    pt:=crangenode.create(pt,comp_expr(true));
                  pt.free;
                  if token=_COMMA then
                    consume(_COMMA)
                  else
                    break;
                until false;
                consume(_COLON);
                { read the vars }
                consume(_LKLAMMER);
                inc(variantrecordlevel);
                if token<>_RKLAMMER then
                  read_record_fields([vd_record]);
                dec(variantrecordlevel);
                consume(_RKLAMMER);
                { calculates maximal variant size }
                maxsize:=max(maxsize,unionsymtable.datasize);
                maxalignment:=max(maxalignment,unionsymtable.fieldalignment);
                maxpadalign:=max(maxpadalign,unionsymtable.padalignment);
                { the items of the next variant are overlayed }
                unionsymtable.datasize:=startvarrecsize;
                unionsymtable.fieldalignment:=startvarrecalign;
                unionsymtable.padalignment:=startpadalign;
                if (token<>_END) and (token<>_RKLAMMER) then
                  consume(_SEMICOLON)
                else
                  break;
              until (token=_END) or (token=_RKLAMMER);
              symtablestack.pop(UnionSymtable);
              { at last set the record size to that of the biggest variant }
              unionsymtable.datasize:=maxsize;
              unionsymtable.fieldalignment:=maxalignment;
              unionsymtable.addalignmentpadding;
{$if defined(powerpc) or defined(powerpc64)}
              { parent inherits the alignment padding if the variant is the first "field" of the parent record/variant }
              if (target_info.system in [system_powerpc_darwin, system_powerpc_macos, system_powerpc64_darwin]) and
                 is_first_field and
                 (recst.usefieldalignment = -1) and
                 (maxpadalign > recst.padalignment) then
                recst.padalignment:=maxpadalign;
{$endif powerpc or powerpc64}
              { Align the offset where the union symtable is added }
              if (recst.usefieldalignment=-1) then
                usedalign:=used_align(unionsymtable.recordalignment,current_settings.alignment.recordalignmin,current_settings.alignment.maxCrecordalign)
              else
                usedalign:=used_align(unionsymtable.recordalignment,current_settings.alignment.recordalignmin,current_settings.alignment.recordalignmax);

              offset:=align(recst.datasize,usedalign);
              recst.datasize:=offset+unionsymtable.datasize;

              if unionsymtable.recordalignment>recst.fieldalignment then
                recst.fieldalignment:=unionsymtable.recordalignment;

              trecordsymtable(recst).insertunionst(Unionsymtable,offset);
              uniondef.owner.deletedef(uniondef);
           end;
         block_type:=old_block_type;
         current_object_option:=old_current_object_option;
         { free the list }
         sc.free;
{$ifdef powerpc}
         is_first_field := false;
{$endif powerpc}
      end;

end.