freepascal.compiler/compiler/tccnv.pas

{
    $Id$
    Copyright (c) 1993-98 by Florian Klaempfl

    Type checking and register allocation for type converting nodes

    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.

 ****************************************************************************
}
{$ifdef TP}
  {$E+,F+,N+,D+,L+,Y+}
{$endif}
unit tccnv;
interface

    uses
      tree;

    procedure arrayconstructor_to_set(var p:ptree);

    procedure firsttypeconv(var p : ptree);
    procedure firstas(var p : ptree);
    procedure firstis(var p : ptree);


implementation

   uses
      globtype,systems,tokens,
      cobjects,verbose,globals,
      symconst,symtable,aasm,types,
{$ifdef newcg}
      cgbase,
{$else newcg}
      hcodegen,
{$endif newcg}
      htypechk,pass_1,cpubase;


{*****************************************************************************
                    Array constructor to Set Conversion
*****************************************************************************}

    procedure arrayconstructor_to_set(var p:ptree);
      var
        constp,
        buildp,
        p2,p3,p4    : ptree;
        pd        : pdef;
        constset    : pconstset;
        constsetlo,
        constsethi  : longint;

        procedure update_constsethi(p:pdef);
        begin
          if ((p^.deftype=orddef) and
              (porddef(p)^.high>constsethi)) then
            constsethi:=porddef(p)^.high
          else
            if ((p^.deftype=enumdef) and
                (penumdef(p)^.max>constsethi)) then
              constsethi:=penumdef(p)^.max;
        end;

        procedure do_set(pos : longint);
        var
          mask,l : longint;
        begin
          if (pos>255) or (pos<0) then
           Message(parser_e_illegal_set_expr);
          if pos>constsethi then
           constsethi:=pos;
          if pos<constsetlo then
           constsetlo:=pos;
          l:=pos shr 3;
          mask:=1 shl (pos mod 8);
          { do we allow the same twice }
          if (constset^[l] and mask)<>0 then
           Message(parser_e_illegal_set_expr);
          constset^[l]:=constset^[l] or mask;
        end;

      var
        l : longint;
        lr,hr : longint;

      begin
        new(constset);
        FillChar(constset^,sizeof(constset^),0);
        pd:=nil;
        constsetlo:=0;
        constsethi:=0;
        constp:=gensinglenode(setconstn,nil);
        constp^.value_set:=constset;
        buildp:=constp;
        if assigned(p^.left) then
         begin
           while assigned(p) do
            begin
              p4:=nil; { will contain the tree to create the set }
            { split a range into p2 and p3 }
              if p^.left^.treetype=arrayconstructrangen then
               begin
                 p2:=p^.left^.left;
                 p3:=p^.left^.right;
               { node is not used anymore }
                 putnode(p^.left);
               end
              else
               begin
                 p2:=p^.left;
                 p3:=nil;
               end;
              firstpass(p2);
              if assigned(p3) then
               firstpass(p3);
              if codegenerror then
               break;
              case p2^.resulttype^.deftype of
                 enumdef,
                 orddef:
                   begin
                      getrange(p2^.resulttype,lr,hr);

                      if is_integer(p2^.resulttype) and
                        ((lr<0) or (hr>255)) then
                       begin
                          p2:=gentypeconvnode(p2,u8bitdef);
                          firstpass(p2);
                       end;
                      { set settype result }
                      if pd=nil then
                        pd:=p2^.resulttype;
                      if not(is_equal(pd,p2^.resulttype)) then
                       begin
                         aktfilepos:=p2^.fileinfo;
                         CGMessage(type_e_typeconflict_in_set);
                         disposetree(p2);
                       end
                      else
                       begin
                         if assigned(p3) then
                          begin
                            if is_integer(p3^.resulttype) then
                             begin
                               p3:=gentypeconvnode(p3,u8bitdef);
                               firstpass(p3);
                             end;
                            if not(is_equal(pd,p3^.resulttype)) then
                              begin
                                 aktfilepos:=p3^.fileinfo;
                                 CGMessage(type_e_typeconflict_in_set);
                              end
                            else
                              begin
                                if (p2^.treetype=ordconstn) and (p3^.treetype=ordconstn) then
                                 begin
                                   for l:=p2^.value to p3^.value do
                                    do_set(l);
                                   disposetree(p3);
                                   disposetree(p2);
                                 end
                                else
                                 begin
                                   update_constsethi(p3^.resulttype);
                                   p4:=gennode(setelementn,p2,p3);
                                 end;
                              end;
                          end
                         else
                          begin
                         { Single value }
                            if p2^.treetype=ordconstn then
                             begin
                               do_set(p2^.value);
                               disposetree(p2);
                             end
                            else
                             begin
                               update_constsethi(p2^.resulttype);
                               p4:=gennode(setelementn,p2,nil);
                             end;
                          end;
                       end;
                    end;
          stringdef : begin
                        if pd=nil then
                         pd:=cchardef;
                        if not(is_equal(pd,cchardef)) then
                         CGMessage(type_e_typeconflict_in_set)
                        else
                         for l:=1 to length(pstring(p2^.value_str)^) do
                          do_set(ord(pstring(p2^.value_str)^[l]));
                        disposetree(p2);
                      end;
              else
               CGMessage(type_e_ordinal_expr_expected);
              end;
            { insert the set creation tree }
              if assigned(p4) then
               buildp:=gennode(addn,buildp,p4);
            { load next and dispose current node }
              p2:=p;
              p:=p^.right;
              putnode(p2);
            end;
         end
        else
         begin
         { empty set [], only remove node }
           putnode(p);
         end;
      { set the initial set type }
        constp^.resulttype:=new(psetdef,init(pd,constsethi));
      { set the new tree }
        p:=buildp;
      end;


{*****************************************************************************
                             FirstTypeConv
*****************************************************************************}

    type
       tfirstconvproc = procedure(var p : ptree);

    procedure first_int_to_int(var p : ptree);
      begin
        if (p^.left^.location.loc<>LOC_REGISTER) and
           (p^.resulttype^.size>p^.left^.resulttype^.size) then
           p^.location.loc:=LOC_REGISTER;
        if is_64bitint(p^.resulttype) then
          p^.registers32:=max(p^.registers32,2)
        else
          p^.registers32:=max(p^.registers32,1);
      end;


    procedure first_cstring_to_pchar(var p : ptree);
      begin
         p^.registers32:=1;
         p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_string_to_chararray(var p : ptree);
      begin
         p^.registers32:=1;
         p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_string_to_string(var p : ptree);
      var
        hp : ptree;
      begin
         if pstringdef(p^.resulttype)^.string_typ<>
            pstringdef(p^.left^.resulttype)^.string_typ then
           begin
              if p^.left^.treetype=stringconstn then
                begin
                   p^.left^.stringtype:=pstringdef(p^.resulttype)^.string_typ;
                   p^.left^.resulttype:=p^.resulttype;
                   { remove typeconv node }
                   hp:=p;
                   p:=p^.left;
                   putnode(hp);
                   exit;
                end
              else
                procinfo^.flags:=procinfo^.flags or pi_do_call;
           end;
         { for simplicity lets first keep all ansistrings
           as LOC_MEM, could also become LOC_REGISTER }
         p^.location.loc:=LOC_MEM;
      end;


    procedure first_char_to_string(var p : ptree);
      var
         hp : ptree;
      begin
         if p^.left^.treetype=ordconstn then
           begin
              hp:=genstringconstnode(chr(p^.left^.value));
              hp^.stringtype:=pstringdef(p^.resulttype)^.string_typ;
              firstpass(hp);
              disposetree(p);
              p:=hp;
           end
         else
           p^.location.loc:=LOC_MEM;
      end;


    procedure first_nothing(var p : ptree);
      begin
         p^.location.loc:=LOC_MEM;
      end;


    procedure first_array_to_pointer(var p : ptree);
      begin
         if p^.registers32<1 then
           p^.registers32:=1;
         p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_int_to_real(var p : ptree);
      var
        t : ptree;
      begin
        if p^.left^.treetype=ordconstn then
         begin
           t:=genrealconstnode(p^.left^.value,pfloatdef(p^.resulttype));
           firstpass(t);
           disposetree(p);
           p:=t;
           exit;
         end;
        if p^.registersfpu<1 then
         p^.registersfpu:=1;
        p^.location.loc:=LOC_FPU;
      end;


    procedure first_int_to_fix(var p : ptree);
      var
        t : ptree;
      begin
        if p^.left^.treetype=ordconstn then
         begin
           t:=genfixconstnode(p^.left^.value shl 16,p^.resulttype);
           firstpass(t);
           disposetree(p);
           p:=t;
           exit;
         end;
        if p^.registers32<1 then
         p^.registers32:=1;
        p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_real_to_fix(var p : ptree);
      var
        t : ptree;
      begin
        if p^.left^.treetype=fixconstn then
         begin
           t:=genfixconstnode(round(p^.left^.value_real*65536),p^.resulttype);
           firstpass(t);
           disposetree(p);
           p:=t;
           exit;
         end;
        { at least one fpu and int register needed }
        if p^.registers32<1 then
          p^.registers32:=1;
        if p^.registersfpu<1 then
          p^.registersfpu:=1;
        p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_fix_to_real(var p : ptree);
      var
        t : ptree;
      begin
        if p^.left^.treetype=fixconstn then
          begin
            t:=genrealconstnode(round(p^.left^.value_fix/65536.0),p^.resulttype);
            firstpass(t);
            disposetree(p);
            p:=t;
            exit;
          end;
        if p^.registersfpu<1 then
          p^.registersfpu:=1;
        p^.location.loc:=LOC_FPU;
      end;


    procedure first_real_to_real(var p : ptree);
      var
        t : ptree;
      begin
         if p^.left^.treetype=realconstn then
           begin
             t:=genrealconstnode(p^.left^.value_real,p^.resulttype);
             firstpass(t);
             disposetree(p);
             p:=t;
             exit;
           end;
        { comp isn't a floating type }
{$ifdef i386}
         if (pfloatdef(p^.resulttype)^.typ=s64comp) and
            (pfloatdef(p^.left^.resulttype)^.typ<>s64comp) and
            not (p^.explizit) then
           CGMessage(type_w_convert_real_2_comp);
{$endif}
         if p^.registersfpu<1 then
           p^.registersfpu:=1;
         p^.location.loc:=LOC_FPU;
      end;


    procedure first_pointer_to_array(var p : ptree);
      begin
         if p^.registers32<1 then
           p^.registers32:=1;
         p^.location.loc:=LOC_REFERENCE;
      end;


    procedure first_chararray_to_string(var p : ptree);
      begin
         { the only important information is the location of the }
         { result                                               }
         { other stuff is done by firsttypeconv           }
         p^.location.loc:=LOC_MEM;
      end;


    procedure first_cchar_to_pchar(var p : ptree);
      begin
         p^.left:=gentypeconvnode(p^.left,cshortstringdef);
         { convert constant char to constant string }
         firstpass(p^.left);
         { evalute tree }
         firstpass(p);
      end;


    procedure first_bool_to_int(var p : ptree);
      begin
         { byte(boolean) or word(wordbool) or longint(longbool) must
         be accepted for var parameters }
         if (p^.explizit) and
            (p^.left^.resulttype^.size=p^.resulttype^.size) and
            (p^.left^.location.loc in [LOC_REFERENCE,LOC_MEM,LOC_CREGISTER]) then
           exit;
         p^.location.loc:=LOC_REGISTER;
         if p^.registers32<1 then
           p^.registers32:=1;
      end;


    procedure first_int_to_bool(var p : ptree);
      begin
         { byte(boolean) or word(wordbool) or longint(longbool) must
         be accepted for var parameters }
         if (p^.explizit) and
            (p^.left^.resulttype^.size=p^.resulttype^.size) and
            (p^.left^.location.loc in [LOC_REFERENCE,LOC_MEM,LOC_CREGISTER]) then
           exit;
         p^.location.loc:=LOC_REGISTER;
         { need if bool to bool !!
           not very nice !!
         p^.left:=gentypeconvnode(p^.left,s32bitdef);
         p^.left^.explizit:=true;
         firstpass(p^.left);  }
         if p^.registers32<1 then
           p^.registers32:=1;
      end;


    procedure first_bool_to_bool(var p : ptree);
      begin
         p^.location.loc:=LOC_REGISTER;
         if p^.registers32<1 then
           p^.registers32:=1;
      end;


    procedure first_proc_to_procvar(var p : ptree);
      begin
         { hmmm, I'am not sure if that is necessary (FK) }
         firstpass(p^.left);
         if codegenerror then
           exit;

         if (p^.left^.location.loc<>LOC_REFERENCE) then
           CGMessage(cg_e_illegal_expression);

         p^.registers32:=p^.left^.registers32;
         if p^.registers32<1 then
           p^.registers32:=1;
         p^.location.loc:=LOC_REGISTER;
      end;


    procedure first_load_smallset(var p : ptree);
      begin
      end;


    procedure first_cord_to_pointer(var p : ptree);
      var
        t : ptree;
      begin
        if p^.left^.treetype=ordconstn then
          begin
            t:=genpointerconstnode(p^.left^.value,p^.resulttype);
            firstpass(t);
            disposetree(p);
            p:=t;
            exit;
          end
        else
          internalerror(432472389);
      end;


    procedure first_pchar_to_string(var p : ptree);
      begin
         p^.location.loc:=LOC_REFERENCE;
      end;


    procedure first_ansistring_to_pchar(var p : ptree);
      begin
         p^.location.loc:=LOC_REGISTER;
         if p^.registers32<1 then
           p^.registers32:=1;
      end;


    procedure first_arrayconstructor_to_set(var p:ptree);
      var
        hp : ptree;
      begin
        if p^.left^.treetype<>arrayconstructn then
         internalerror(5546);
      { remove typeconv node }
        hp:=p;
        p:=p^.left;
        putnode(hp);
      { create a set constructor tree }
        arrayconstructor_to_set(p);
      { now firstpass the set }
        firstpass(p);
      end;


  procedure firsttypeconv(var p : ptree);
    var
      hp : ptree;
      aprocdef : pprocdef;
    const
       firstconvert : array[tconverttype] of tfirstconvproc = (
         first_nothing, {equal}
         first_nothing, {not_possible}
         first_string_to_string,
         first_char_to_string,
         first_pchar_to_string,
         first_cchar_to_pchar,
         first_cstring_to_pchar,
         first_ansistring_to_pchar,
         first_string_to_chararray,
         first_chararray_to_string,
         first_array_to_pointer,
         first_pointer_to_array,
         first_int_to_int,
         first_int_to_bool,
         first_bool_to_bool,
         first_bool_to_int,
         first_real_to_real,
         first_int_to_real,
         first_int_to_fix,
         first_real_to_fix,
         first_fix_to_real,
         first_proc_to_procvar,
         first_arrayconstructor_to_set,
         first_load_smallset,
         first_cord_to_pointer
       );
     begin
       aprocdef:=nil;
       { if explicite type cast, then run firstpass }
       if p^.explizit then
         firstpass(p^.left);
       if (p^.left^.treetype=typen) and (p^.left^.resulttype=generrordef) then
         begin
            codegenerror:=true;
            Message(parser_e_no_type_not_allowed_here);
         end;
       if codegenerror then
         begin
           p^.resulttype:=generrordef;
           exit;
         end;

       if not assigned(p^.left^.resulttype) then
        begin
          codegenerror:=true;
          internalerror(52349);
          exit;
        end;

       { load the value_str from the left part }
       p^.registers32:=p^.left^.registers32;
       p^.registersfpu:=p^.left^.registersfpu;
{$ifdef SUPPORT_MMX}
       p^.registersmmx:=p^.left^.registersmmx;
{$endif}
       set_location(p^.location,p^.left^.location);

       { remove obsolete type conversions }
       if is_equal(p^.left^.resulttype,p^.resulttype) then
         begin
         { becuase is_equal only checks the basetype for sets we need to
           check here if we are loading a smallset into a normalset }
           if (p^.resulttype^.deftype=setdef) and
              (p^.left^.resulttype^.deftype=setdef) and
              (psetdef(p^.resulttype)^.settype<>smallset) and
              (psetdef(p^.left^.resulttype)^.settype=smallset) then
            begin
            { try to define the set as a normalset if it's a constant set }
              if p^.left^.treetype=setconstn then
               begin
                 p^.resulttype:=p^.left^.resulttype;
                 psetdef(p^.resulttype)^.settype:=normset
               end
              else
               p^.convtyp:=tc_load_smallset;
              exit;
            end
           else
            begin
              hp:=p;
              p:=p^.left;
              p^.resulttype:=hp^.resulttype;
              putnode(hp);
              exit;
            end;
         end;
       aprocdef:=assignment_overloaded(p^.left^.resulttype,p^.resulttype);
       if assigned(aprocdef) then
         begin
            procinfo^.flags:=procinfo^.flags or pi_do_call;
            hp:=gencallnode(overloaded_operators[_assignment],nil);
            { tell explicitly which def we must use !! (PM) }
            hp^.procdefinition:=aprocdef;
            hp^.left:=gencallparanode(p^.left,nil);
            putnode(p);
            p:=hp;
            firstpass(p);
            exit;
         end;

       if isconvertable(p^.left^.resulttype,p^.resulttype,p^.convtyp,p^.left^.treetype,p^.explizit)=0 then
         begin
           {Procedures have a resulttype of voiddef and functions of their
           own resulttype. They will therefore always be incompatible with
           a procvar. Because isconvertable cannot check for procedures we
           use an extra check for them.}
           if (m_tp_procvar in aktmodeswitches) then
            begin
              if (p^.resulttype^.deftype=procvardef) and
                 (is_procsym_load(p^.left) or is_procsym_call(p^.left)) then
               begin
                 if is_procsym_call(p^.left) then
                  begin
                    {if p^.left^.right=nil then
                     begin}
                       if (p^.left^.symtableprocentry^.owner^.symtabletype=objectsymtable){ and
                          (pobjectdef(p^.left^.symtableprocentry^.owner^.defowner)^.is_class) }then
                        hp:=genloadmethodcallnode(pprocsym(p^.left^.symtableprocentry),p^.left^.symtableproc,
                              getcopy(p^.left^.methodpointer))
                       else
                        hp:=genloadcallnode(pprocsym(p^.left^.symtableprocentry),p^.left^.symtableproc);
                       disposetree(p^.left);
                       firstpass(hp);
                       p^.left:=hp;
                       aprocdef:=pprocdef(p^.left^.resulttype);
                   (*  end
                    else
                     begin
                       p^.left^.right^.treetype:=loadn;
                       p^.left^.right^.symtableentry:=p^.left^.right^.symtableentry;
                       P^.left^.right^.resulttype:=pvarsym(p^.left^.symtableentry)^.definition;
                       hp:=p^.left^.right;
                       putnode(p^.left);
                       p^.left:=hp;
                       { should we do that ? }
                       firstpass(p^.left);
                       if not is_equal(p^.left^.resulttype,p^.resulttype) then
                        begin
                          CGMessage(type_e_mismatch);
                          exit;
                        end
                       else
                        begin
                          hp:=p;
                          p:=p^.left;
                          p^.resulttype:=hp^.resulttype;
                          putnode(hp);
                          exit;
                        end;
                     end; *)
                  end
                 else
                  begin
                    if (p^.left^.treetype<>addrn) then
                      aprocdef:=pprocsym(p^.left^.symtableentry)^.definition;
                  end;
                 p^.convtyp:=tc_proc_2_procvar;
                 { Now check if the procedure we are going to assign to
                   the procvar,  is compatible with the procvar's type }
                 if assigned(aprocdef) then
                  begin
                    if not proc_to_procvar_equal(aprocdef,pprocvardef(p^.resulttype)) then
                     CGMessage2(type_e_incompatible_types,aprocdef^.typename,p^.resulttype^.typename);
                    firstconvert[p^.convtyp](p);
                  end
                 else
                  CGMessage2(type_e_incompatible_types,p^.left^.resulttype^.typename,p^.resulttype^.typename);
                 exit;
               end;
            end;
           if p^.explizit then
            begin
              { check if the result could be in a register }
              if not(p^.resulttype^.is_intregable) and
                not(p^.resulttype^.is_fpuregable) then
                make_not_regable(p^.left);
              { boolean to byte are special because the
                location can be different }

              if is_integer(p^.resulttype) and
                 is_boolean(p^.left^.resulttype) then
               begin
                  p^.convtyp:=tc_bool_2_int;
                  firstconvert[p^.convtyp](p);
                  exit;
               end;
              { ansistring to pchar }
              if is_pchar(p^.resulttype) and
                 is_ansistring(p^.left^.resulttype) then
               begin
                 p^.convtyp:=tc_ansistring_2_pchar;
                 firstconvert[p^.convtyp](p);
                 exit;
               end;
              { do common tc_equal cast }
              p^.convtyp:=tc_equal;

              { enum to ordinal will always be s32bit }
              if (p^.left^.resulttype^.deftype=enumdef) and
                 is_ordinal(p^.resulttype) then
               begin
                 if p^.left^.treetype=ordconstn then
                  begin
                    hp:=genordinalconstnode(p^.left^.value,p^.resulttype);
                    disposetree(p);
                    firstpass(hp);
                    p:=hp;
                    exit;
                  end
                 else
                  begin
                    if isconvertable(s32bitdef,p^.resulttype,p^.convtyp,ordconstn,false)=0 then
                      CGMessage(cg_e_illegal_type_conversion);
                  end;
               end

              { ordinal to enumeration }
              else
               if (p^.resulttype^.deftype=enumdef) and
                  is_ordinal(p^.left^.resulttype) then
                begin
                  if p^.left^.treetype=ordconstn then
                   begin
                     hp:=genordinalconstnode(p^.left^.value,p^.resulttype);
                     disposetree(p);
                     firstpass(hp);
                     p:=hp;
                     exit;
                   end
                  else
                   begin
                     if IsConvertable(p^.left^.resulttype,s32bitdef,p^.convtyp,ordconstn,false)=0 then
                       CGMessage(cg_e_illegal_type_conversion);
                   end;
                end

              {Are we typecasting an ordconst to a char?}
              else
                if is_char(p^.resulttype) and
                   is_ordinal(p^.left^.resulttype) then
                 begin
                   if p^.left^.treetype=ordconstn then
                    begin
                      hp:=genordinalconstnode(p^.left^.value,p^.resulttype);
                      firstpass(hp);
                      disposetree(p);
                      p:=hp;
                      exit;
                    end
                   else
                    begin
                      { this is wrong because it converts to a 4 byte long var !!
                      if not isconvertable(p^.left^.resulttype,s32bitdef,p^.convtyp,ordconstn  nur Dummy ) then }
                      if IsConvertable(p^.left^.resulttype,u8bitdef,p^.convtyp,ordconstn,false)=0 then
                        CGMessage(cg_e_illegal_type_conversion);
                    end;
                 end

               { only if the same size or formal def }
               { why do we allow typecasting of voiddef ?? (PM) }
               else
                begin
                  if not(
                     (p^.left^.resulttype^.deftype=formaldef) or
                     (p^.left^.resulttype^.size=p^.resulttype^.size) or
                     (is_equal(p^.left^.resulttype,voiddef)  and
                     (p^.left^.treetype=derefn))
                     ) then
                    CGMessage(cg_e_illegal_type_conversion);
                  if ((p^.left^.resulttype^.deftype=orddef) and
                      (p^.resulttype^.deftype=pointerdef)) or
                      ((p^.resulttype^.deftype=orddef) and
                       (p^.left^.resulttype^.deftype=pointerdef))
                       {$ifdef extdebug}and (p^.firstpasscount=0){$endif} then
                    CGMessage(cg_d_pointer_to_longint_conv_not_portable);
                end;

               { the conversion into a strutured type is only }
               { possible, if the source is no register    }
               if ((p^.resulttype^.deftype in [recorddef,stringdef,arraydef]) or
                   ((p^.resulttype^.deftype=objectdef) and not(pobjectdef(p^.resulttype)^.is_class))
                  ) and (p^.left^.location.loc in [LOC_REGISTER,LOC_CREGISTER]) { and
                   it also works if the assignment is overloaded
                   YES but this code is not executed if assignment is overloaded (PM)
                  not assigned(assignment_overloaded(p^.left^.resulttype,p^.resulttype))} then
                 CGMessage(cg_e_illegal_type_conversion);
            end
           else
            CGMessage2(type_e_incompatible_types,p^.left^.resulttype^.typename,p^.resulttype^.typename);
         end;

       { tp7 procvar support, when right is not a procvardef and we got a
         loadn of a procvar then convert to a calln, the check for the
         result is already done in is_convertible, also no conflict with
         @procvar is here because that has an extra addrn }
         if (m_tp_procvar in aktmodeswitches) and
            (p^.resulttype^.deftype<>procvardef) and
            (p^.left^.resulttype^.deftype=procvardef) and
            (p^.left^.treetype=loadn) then
          begin
            hp:=gencallnode(nil,nil);
            hp^.right:=p^.left;
            firstpass(hp);
            p^.left:=hp;
          end;


        { ordinal contants can be directly converted }
        { but not int64/qword                        }
        if (p^.left^.treetype=ordconstn) and is_ordinal(p^.resulttype) and
          not(is_64bitint(p^.resulttype)) then
          begin
             { range checking is done in genordinalconstnode (PFV) }
             hp:=genordinalconstnode(p^.left^.value,p^.resulttype);
             disposetree(p);
             firstpass(hp);
             p:=hp;
             exit;
          end;
        if p^.convtyp<>tc_equal then
          firstconvert[p^.convtyp](p);
      end;


{*****************************************************************************
                                FirstIs
*****************************************************************************}

    procedure firstis(var p : ptree);
      var
         Store_valid : boolean;
      begin
         Store_valid:=Must_be_valid;
         Must_be_valid:=true;
         firstpass(p^.left);
         firstpass(p^.right);
         Must_be_valid:=Store_valid;
         if codegenerror then
           exit;

         if (p^.right^.resulttype^.deftype<>classrefdef) then
           CGMessage(type_e_mismatch);

         left_right_max(p);

         { left must be a class }
         if (p^.left^.resulttype^.deftype<>objectdef) or
            not(pobjectdef(p^.left^.resulttype)^.is_class) then
           CGMessage(type_e_mismatch);

         { the operands must be related }
         if (not(pobjectdef(p^.left^.resulttype)^.is_related(
           pobjectdef(pclassrefdef(p^.right^.resulttype)^.definition)))) and
           (not(pobjectdef(pclassrefdef(p^.right^.resulttype)^.definition)^.is_related(
           pobjectdef(p^.left^.resulttype)))) then
           CGMessage(type_e_mismatch);

         p^.location.loc:=LOC_FLAGS;
         p^.resulttype:=booldef;
      end;


{*****************************************************************************
                                FirstAs
*****************************************************************************}

    procedure firstas(var p : ptree);
      var
         Store_valid : boolean;
      begin
         Store_valid:=Must_be_valid;
         Must_be_valid:=true;
         firstpass(p^.right);
         firstpass(p^.left);
         Must_be_valid:=Store_valid;
         if codegenerror then
           exit;

         if (p^.right^.resulttype^.deftype<>classrefdef) then
           CGMessage(type_e_mismatch);

         left_right_max(p);

         { left must be a class }
         if (p^.left^.resulttype^.deftype<>objectdef) or
           not(pobjectdef(p^.left^.resulttype)^.is_class) then
           CGMessage(type_e_mismatch);

         { the operands must be related }
         if (not(pobjectdef(p^.left^.resulttype)^.is_related(
           pobjectdef(pclassrefdef(p^.right^.resulttype)^.definition)))) and
           (not(pobjectdef(pclassrefdef(p^.right^.resulttype)^.definition)^.is_related(
           pobjectdef(p^.left^.resulttype)))) then
           CGMessage(type_e_mismatch);

         set_location(p^.location,p^.left^.location);
         p^.resulttype:=pclassrefdef(p^.right^.resulttype)^.definition;
      end;


end.
{
  $Log$
  Revision 1.52  1999-11-06 14:34:29  peter
    * truncated log to 20 revs

  Revision 1.51  1999/11/05 13:15:00  florian
    * some fixes to get the new cg compiling again

  Revision 1.50  1999/09/27 23:45:00  peter
    * procinfo is now a pointer
    * support for result setting in sub procedure

  Revision 1.49  1999/09/26 21:30:22  peter
    + constant pointer support which can happend with typecasting like
      const p=pointer(1)
    * better procvar parsing in typed consts

  Revision 1.48  1999/09/17 17:14:12  peter
    * @procvar fixes for tp mode
    * @<id>:= gives now an error

  Revision 1.47  1999/09/11 09:08:34  florian
    * fixed bug 596
    * fixed some problems with procedure variables and procedures of object,
      especially in TP mode. Procedure of object doesn't apply only to classes,
      it is also allowed for objects !!

  Revision 1.46  1999/08/13 15:43:59  peter
    * fixed proc->procvar conversion for tp_procvar mode, it now uses
      also the genload(method)call() function

  Revision 1.45  1999/08/07 14:21:04  florian
    * some small problems fixed

  Revision 1.44  1999/08/04 13:03:14  jonas
    * all tokens now start with an underscore
    * PowerPC compiles!!

  Revision 1.43  1999/08/04 00:23:36  florian
    * renamed i386asm and i386base to cpuasm and cpubase

  Revision 1.42  1999/08/03 22:03:28  peter
    * moved bitmask constants to sets
    * some other type/const renamings

  Revision 1.41  1999/06/30 22:16:23  florian
    * use of is_ordinal checked: often a qword/int64 isn't allowed (case/for ...)
    * small qword problems fixed

  Revision 1.40  1999/06/28 22:29:21  florian
    * qword division fixed
    + code for qword/int64 type casting added:
      range checking isn't implemented yet

  Revision 1.39  1999/06/28 19:30:07  peter
    * merged

  Revision 1.35.2.5  1999/06/28 19:07:47  peter
    * remove cstring->string typeconvs after updating cstringn

  Revision 1.35.2.4  1999/06/28 00:33:50  pierre
   * better error position bug0269

  Revision 1.35.2.3  1999/06/17 12:51:48  pierre
   * changed is_assignment_overloaded into
      function assignment_overloaded : pprocdef
      to allow overloading of assignment with only different result type

  Revision 1.35.2.2  1999/06/15 18:54:53  peter
    * more procvar fixes

  Revision 1.35.2.1  1999/06/13 22:39:19  peter
    * use proc_to_procvar_equal

  Revision 1.35  1999/06/02 22:44:24  pierre
   * previous wrong log corrected

  Revision 1.34  1999/06/02 22:25:54  pierre
  * changed $ifdef FPC @ into $ifndef TP
  + debug note about longint to pointer conversion

}