freepascal.compiler/compiler/types.pas

{
    $Id$
    Copyright (C) 1998-2000 by Florian Klaempfl

    This unit provides some help routines for type handling

    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 types;
interface

    uses
       cobjects,symtable;

    type
       tmmxtype = (mmxno,mmxu8bit,mmxs8bit,mmxu16bit,mmxs16bit,
                   mmxu32bit,mmxs32bit,mmxfixed16,mmxsingle);

    const
       { true if we must never copy this parameter }
       never_copy_const_param : boolean = false;

{*****************************************************************************
                          Basic type functions
 *****************************************************************************}

    { returns true, if def defines an ordinal type }
    function is_ordinal(def : pdef) : boolean;

    { returns the min. value of the type }
    function get_min_value(def : pdef) : longint;

    { returns true, if def defines an ordinal type }
    function is_integer(def : pdef) : boolean;

    { true if p is a boolean }
    function is_boolean(def : pdef) : boolean;

    { true if p is a char }
    function is_char(def : pdef) : boolean;

    { true if p is a void}
    function is_void(def : pdef) : boolean;

    { true if p is a smallset def }
    function is_smallset(p : pdef) : boolean;

    { returns true, if def defines a signed data type (only for ordinal types) }
    function is_signed(def : pdef) : boolean;

{*****************************************************************************
                              Array helper functions
 *****************************************************************************}

    { true, if p points to a zero based (non special like open or
      dynamic array def, mainly this is used to see if the array
      is convertable to a pointer }
    function is_zero_based_array(p : pdef) : boolean;

    { true if p points to an open array def }
    function is_open_array(p : pdef) : boolean;

    { true, if p points to an array of const def }
    function is_array_constructor(p : pdef) : boolean;

    { true, if p points to a variant array }
    function is_variant_array(p : pdef) : boolean;

    { true, if p points to an array of const }
    function is_array_of_const(p : pdef) : boolean;

    { true, if p points any kind of special array }
    function is_special_array(p : pdef) : boolean;

    { true if p is a char array def }
    function is_chararray(p : pdef) : boolean;

{*****************************************************************************
                          String helper functions
 *****************************************************************************}

    { true if p points to an open string def }
    function is_open_string(p : pdef) : boolean;

    { true if p is an ansi string def }
    function is_ansistring(p : pdef) : boolean;

    { true if p is a long string def }
    function is_longstring(p : pdef) : boolean;

    { true if p is a wide string def }
    function is_widestring(p : pdef) : boolean;

    { true if p is a short string def }
    function is_shortstring(p : pdef) : boolean;

    { true if p is a pchar def }
    function is_pchar(p : pdef) : boolean;

    { true if p is a voidpointer def }
    function is_voidpointer(p : pdef) : boolean;

    { returns true, if def uses FPU }
    function is_fpu(def : pdef) : boolean;

    { true if the return value is in EAX }
    function ret_in_acc(def : pdef) : boolean;

    { true if uses a parameter as return value }
    function ret_in_param(def : pdef) : boolean;

    { true, if def is a 64 bit int type }
    function is_64bitint(def : pdef) : boolean;

    function push_high_param(def : pdef) : boolean;

    { true if a parameter is too large to copy and only the address is pushed }
    function push_addr_param(def : pdef) : boolean;

    { true, if def1 and def2 are semantical the same }
    function is_equal(def1,def2 : pdef) : boolean;

    { checks for type compatibility (subgroups of type)  }
    { used for case statements... probably missing stuff }
    { to use on other types                              }
    function is_subequal(def1, def2: pdef): boolean;

    { same as is_equal, but with error message if failed }
    function CheckTypes(def1,def2 : pdef) : boolean;

    { true, if two parameter lists are equal        }
    { if value_equal_const is true, call by value   }
    { and call by const parameter are assumed as    }
    { equal                                         }
    function equal_paras(paralist1,paralist2 : plinkedlist;value_equal_const : boolean) : boolean;


    { true if a type can be allowed for another one
      in a func var }
    function convertable_paras(paralist1,paralist2 : plinkedlist;value_equal_const : boolean) : boolean;

    { true if a function can be assigned to a procvar }
    function proc_to_procvar_equal(def1:pprocdef;def2:pprocvardef) : boolean;

    { if l isn't in the range of def a range check error is generated and
      the value is placed within the range }
    procedure testrange(def : pdef;var l : longint);

    { returns the range of def }
    procedure getrange(def : pdef;var l : longint;var h : longint);

    { some type helper routines for MMX support }
    function is_mmx_able_array(p : pdef) : boolean;

    { returns the mmx type }
    function mmx_type(p : pdef) : tmmxtype;

    { returns true, if sym needs an entry in the proplist of a class rtti }
    function needs_prop_entry(sym : psym) : boolean;

implementation

    uses
       strings,globtype,globals,htypechk,
       tree,verbose,symconst;

    function needs_prop_entry(sym : psym) : boolean;

      begin
         needs_prop_entry:=(sp_published in psym(sym)^.symoptions) and
         (sym^.typ in [propertysym,varsym]);
      end;

    function equal_paras(paralist1,paralist2 : plinkedlist;value_equal_const : boolean) : boolean;
      var
        def1,def2 : pparaitem;
      begin
         def1:=pparaitem(paralist1^.first);
         def2:=pparaitem(paralist2^.first);
         while (assigned(def1)) and (assigned(def2)) do
           begin
              if value_equal_const then
                begin
                   if not(is_equal(def1^.paratype.def,def2^.paratype.def)) or
                     ((def1^.paratyp<>def2^.paratyp) and
                      ((def1^.paratyp=vs_var) or
                       (def1^.paratyp=vs_var)
                      )
                     ) then
                     begin
                        equal_paras:=false;
                        exit;
                     end;
                end
              else
                begin
                   if not(is_equal(def1^.paratype.def,def2^.paratype.def)) or
                     (def1^.paratyp<>def2^.paratyp) then
                     begin
                        equal_paras:=false;
                        exit;
                     end;
                end;
              def1:=pparaitem(def1^.next);
              def2:=pparaitem(def2^.next);
           end;
         if (def1=nil) and (def2=nil) then
           equal_paras:=true
         else
           equal_paras:=false;
      end;

    function convertable_paras(paralist1,paralist2 : plinkedlist;value_equal_const : boolean) : boolean;
      var
        def1,def2 : pparaitem;
        doconv : tconverttype;
      begin
         def1:=pparaitem(paralist1^.first);
         def2:=pparaitem(paralist2^.first);
         while (assigned(def1)) and (assigned(def2)) do
           begin
              if value_equal_const then
                begin
                   if (isconvertable(def1^.paratype.def,def2^.paratype.def,doconv,callparan,false)=0) or
                     ((def1^.paratyp<>def2^.paratyp) and
                      ((def1^.paratyp=vs_var) or
                       (def1^.paratyp=vs_var)
                      )
                     ) then
                     begin
                        convertable_paras:=false;
                        exit;
                     end;
                end
              else
                begin
                   if (isconvertable(def1^.paratype.def,def2^.paratype.def,doconv,callparan,false)=0) or
                     (def1^.paratyp<>def2^.paratyp) then
                     begin
                        convertable_paras:=false;
                        exit;
                     end;
                end;
              def1:=pparaitem(def1^.next);
              def2:=pparaitem(def2^.next);
           end;
         if (def1=nil) and (def2=nil) then
           convertable_paras:=true
         else
           convertable_paras:=false;
      end;


    { true if a function can be assigned to a procvar }
    function proc_to_procvar_equal(def1:pprocdef;def2:pprocvardef) : boolean;
      const
        po_comp = po_compatibility_options-[po_methodpointer];
      var
        ismethod : boolean;
      begin
         proc_to_procvar_equal:=false;
         if not(assigned(def1)) or not(assigned(def2)) then
           exit;
         { check for method pointer }
         ismethod:=assigned(def1^.owner) and
                   (def1^.owner^.symtabletype=objectsymtable);
                   { I think methods of objects are also not compatible }
                   { with procedure variables! (FK)
                   and
                   assigned(def1^.owner^.defowner) and
                   (pobjectdef(def1^.owner^.defowner)^.is_class); }
         if (ismethod and not (po_methodpointer in def2^.procoptions)) or
            (not(ismethod) and (po_methodpointer in def2^.procoptions)) then
          begin
            Message(type_e_no_method_and_procedure_not_compatible);
            exit;
          end;
         { check return value and para's and options, methodpointer is already checked
           parameters may also be convertable }
         if is_equal(def1^.rettype.def,def2^.rettype.def) and
            (equal_paras(def1^.para,def2^.para,false) or
             convertable_paras(def1^.para,def2^.para,false)) and
            ((po_comp * def1^.procoptions)= (po_comp * def2^.procoptions)) then
           proc_to_procvar_equal:=true
         else
           proc_to_procvar_equal:=false;
      end;


    { returns true, if def uses FPU }
    function is_fpu(def : pdef) : boolean;
      begin
         is_fpu:=(def^.deftype=floatdef) and (pfloatdef(def)^.typ<>f32bit);
      end;


    { true if p is an ordinal }
    function is_ordinal(def : pdef) : boolean;
      var
         dt : tbasetype;
      begin
         case def^.deftype of
           orddef :
             begin
               dt:=porddef(def)^.typ;
               is_ordinal:=dt in [uchar,
                                  u8bit,u16bit,u32bit,u64bit,
                                  s8bit,s16bit,s32bit,s64bit,
                                  bool8bit,bool16bit,bool32bit];
             end;
           enumdef :
             is_ordinal:=true;
           else
             is_ordinal:=false;
         end;
      end;


    { returns the min. value of the type }
    function get_min_value(def : pdef) : longint;
      begin
         case def^.deftype of
           orddef:
             get_min_value:=porddef(def)^.low;
           enumdef:
             get_min_value:=penumdef(def)^.min;
           else
             get_min_value:=0;
         end;
      end;


    { true if p is an integer }
    function is_integer(def : pdef) : boolean;
      begin
        is_integer:=(def^.deftype=orddef) and
                    (porddef(def)^.typ in [uauto,u8bit,u16bit,u32bit,u64bit,
                                           s8bit,s16bit,s32bit,s64bit]);
      end;


    { true if p is a boolean }
    function is_boolean(def : pdef) : boolean;
      begin
        is_boolean:=(def^.deftype=orddef) and
                    (porddef(def)^.typ in [bool8bit,bool16bit,bool32bit]);
      end;


    { true if p is a void }
    function is_void(def : pdef) : boolean;
      begin
        is_void:=(def^.deftype=orddef) and
                 (porddef(def)^.typ=uvoid);
      end;


    { true if p is a char }
    function is_char(def : pdef) : boolean;
      begin
        is_char:=(def^.deftype=orddef) and
                 (porddef(def)^.typ=uchar);
      end;


    { true if p is signed (integer) }
    function is_signed(def : pdef) : boolean;
      var
         dt : tbasetype;
      begin
         case def^.deftype of
           orddef :
             begin
               dt:=porddef(def)^.typ;
               is_signed:=(dt in [s8bit,s16bit,s32bit,s64bit]);
             end;
           enumdef :
             is_signed:=false;
           else
             is_signed:=false;
         end;
      end;


    { true, if p points to an open array def }
    function is_open_string(p : pdef) : boolean;
      begin
         is_open_string:=(p^.deftype=stringdef) and
                         (pstringdef(p)^.string_typ=st_shortstring) and
                         (pstringdef(p)^.len=0);
      end;


    { true, if p points to a zero based array def }
    function is_zero_based_array(p : pdef) : boolean;
      begin
         is_zero_based_array:=(p^.deftype=arraydef) and
                              (parraydef(p)^.lowrange=0) and
                              not(is_special_array(p));
      end;

    { true, if p points to an open array def }
    function is_open_array(p : pdef) : boolean;
      begin
         { check for s32bitdef is needed, because for u32bit the high
           range is also -1 ! (PFV) }
         is_open_array:=(p^.deftype=arraydef) and
                        (parraydef(p)^.rangetype.def=pdef(s32bitdef)) and
                        (parraydef(p)^.lowrange=0) and
                        (parraydef(p)^.highrange=-1) and
                        not(parraydef(p)^.IsConstructor) and
                        not(parraydef(p)^.IsVariant) and
                        not(parraydef(p)^.IsArrayOfConst);

      end;

    { true, if p points to an array of const def }
    function is_array_constructor(p : pdef) : boolean;
      begin
         is_array_constructor:=(p^.deftype=arraydef) and
                        (parraydef(p)^.IsConstructor);
      end;

    { true, if p points to a variant array }
    function is_variant_array(p : pdef) : boolean;
      begin
         is_variant_array:=(p^.deftype=arraydef) and
                        (parraydef(p)^.IsVariant);
      end;

    { true, if p points to an array of const }
    function is_array_of_const(p : pdef) : boolean;
      begin
         is_array_of_const:=(p^.deftype=arraydef) and
                        (parraydef(p)^.IsArrayOfConst);
      end;

    { true, if p points to a special array }
    function is_special_array(p : pdef) : boolean;
      begin
         is_special_array:=(p^.deftype=arraydef) and
                        ((parraydef(p)^.IsVariant) or
                         (parraydef(p)^.IsArrayOfConst) or
                         (parraydef(p)^.IsConstructor) or
                         is_open_array(p)
                        );
      end;

    { true if p is an ansi string def }
    function is_ansistring(p : pdef) : boolean;
      begin
         is_ansistring:=(p^.deftype=stringdef) and
                        (pstringdef(p)^.string_typ=st_ansistring);
      end;


    { true if p is an long string def }
    function is_longstring(p : pdef) : boolean;
      begin
         is_longstring:=(p^.deftype=stringdef) and
                        (pstringdef(p)^.string_typ=st_longstring);
      end;


    { true if p is an wide string def }
    function is_widestring(p : pdef) : boolean;
      begin
         is_widestring:=(p^.deftype=stringdef) and
                        (pstringdef(p)^.string_typ=st_widestring);
      end;


    { true if p is an short string def }
    function is_shortstring(p : pdef) : boolean;
      begin
         is_shortstring:=(p^.deftype=stringdef) and
                         (pstringdef(p)^.string_typ=st_shortstring);
      end;

    { true if p is a char array def }
    function is_chararray(p : pdef) : boolean;
      begin
        is_chararray:=(p^.deftype=arraydef) and
                      is_equal(parraydef(p)^.elementtype.def,cchardef) and
                      not(is_special_array(p));
      end;


    { true if p is a pchar def }
    function is_pchar(p : pdef) : boolean;
      begin
        is_pchar:=(p^.deftype=pointerdef) and
                  is_equal(Ppointerdef(p)^.pointertype.def,cchardef);
      end;


    { true if p is a voidpointer def }
    function is_voidpointer(p : pdef) : boolean;
      begin
        is_voidpointer:=(p^.deftype=pointerdef) and
                        is_equal(Ppointerdef(p)^.pointertype.def,voiddef);
      end;


    { true if p is a smallset def }
    function is_smallset(p : pdef) : boolean;
      begin
        is_smallset:=(p^.deftype=setdef) and
                     (psetdef(p)^.settype=smallset);
      end;


    { true if the return value is in accumulator (EAX for i386), D0 for 68k }
    function ret_in_acc(def : pdef) : boolean;
      begin
         ret_in_acc:=(def^.deftype in [orddef,pointerdef,enumdef,classrefdef]) or
                     ((def^.deftype=stringdef) and (pstringdef(def)^.string_typ in [st_ansistring,st_widestring])) or
                     ((def^.deftype=procvardef) and not(po_methodpointer in pprocvardef(def)^.procoptions)) or
                     ((def^.deftype=objectdef) and pobjectdef(def)^.is_class) or
                     ((def^.deftype=setdef) and (psetdef(def)^.settype=smallset)) or
                     ((def^.deftype=floatdef) and (pfloatdef(def)^.typ=f32bit));
      end;


    { true, if def is a 64 bit int type }
    function is_64bitint(def : pdef) : boolean;
      begin
         is_64bitint:=(def^.deftype=orddef) and (porddef(def)^.typ in [u64bit,s64bit])
      end;


    { true if uses a parameter as return value }
    function ret_in_param(def : pdef) : boolean;
      begin
         ret_in_param:=(def^.deftype in [arraydef,recorddef]) or
           ((def^.deftype=stringdef) and (pstringdef(def)^.string_typ in [st_shortstring,st_longstring])) or
           ((def^.deftype=procvardef) and (po_methodpointer in pprocvardef(def)^.procoptions)) or
           ((def^.deftype=objectdef) and not(pobjectdef(def)^.is_class)) or
           ((def^.deftype=setdef) and (psetdef(def)^.settype<>smallset));
      end;


    function push_high_param(def : pdef) : boolean;
      begin
         push_high_param:=is_open_array(def) or
                          is_open_string(def) or
                          is_array_of_const(def);
      end;


    { true if a parameter is too large to copy and only the address is pushed }
    function push_addr_param(def : pdef) : boolean;
      begin
        push_addr_param:=false;
        if never_copy_const_param then
         push_addr_param:=true
        else
         begin
           case def^.deftype of
             formaldef :
               push_addr_param:=true;
             recorddef :
               push_addr_param:=(def^.size>4);
             arraydef :
               push_addr_param:=((Parraydef(def)^.highrange>Parraydef(def)^.lowrange) and (def^.size>4)) or
                                is_open_array(def) or
                                is_array_of_const(def) or
                                is_array_constructor(def);
             objectdef :
               push_addr_param:=not(pobjectdef(def)^.is_class);
             stringdef :
               push_addr_param:=pstringdef(def)^.string_typ in [st_shortstring,st_longstring];
             procvardef :
               push_addr_param:=(po_methodpointer in pprocvardef(def)^.procoptions);
             setdef :
               push_addr_param:=(psetdef(def)^.settype<>smallset);
           end;
         end;
      end;

    { test if l is in the range of def, outputs error if out of range }
    procedure testrange(def : pdef;var l : longint);
      var
         lv,hv: longint;

      begin
         { for 64 bit types we need only to check if it is less than }
         { zero, if def is a qword node                              }
         if is_64bitint(def) then
           begin
              if (l<0) and (porddef(def)^.typ=u64bit) then
                begin
                   l:=0;
                   if (cs_check_range in aktlocalswitches) then
                     Message(parser_e_range_check_error)
                   else
                     Message(parser_w_range_check_error);
                end;
           end
         else
           begin
              getrange(def,lv,hv);
              if (def^.deftype=orddef) and
                 (porddef(def)^.typ=u32bit) then
                begin
                   if lv<=hv then
                     begin
                        if (l<lv) or (l>hv) then
                          begin
                             if (cs_check_range in aktlocalswitches) then
                               Message(parser_e_range_check_error)
                             else
                               Message(parser_w_range_check_error);
                          end;
                     end
                   else
                     { this happens with the wrap around problem  }
                     { if lv is positive and hv is over $7ffffff  }
                     { so it seems negative                       }
                     begin
                        if ((l>=0) and (l<lv)) or
                           ((l<0) and (l>hv)) then
                          begin
                             if (cs_check_range in aktlocalswitches) then
                               Message(parser_e_range_check_error)
                             else
                               Message(parser_w_range_check_error);
                          end;
                     end;
                end
              else if (l<lv) or (l>hv) then
                begin
                   if (def^.deftype=enumdef) or
                      (cs_check_range in aktlocalswitches) then
                     Message(parser_e_range_check_error)
                   else
                     Message(parser_w_range_check_error);
                   { Fix the value to fit in the allocated space for this type of variable }
                     case def^.size of
                       1: l := l and $ff;
                       2: l := l and $ffff;
                     end
{                   l:=lv+(l mod (hv-lv+1));}
                end;
           end;
      end;


    { return the range from def in l and h }
    procedure getrange(def : pdef;var l : longint;var h : longint);
      begin
        case def^.deftype of
          orddef :
            begin
              l:=porddef(def)^.low;
              h:=porddef(def)^.high;
            end;
          enumdef :
            begin
              l:=penumdef(def)^.min;
              h:=penumdef(def)^.max;
            end;
          arraydef :
            begin
              l:=parraydef(def)^.lowrange;
              h:=parraydef(def)^.highrange;
            end;
        else
          internalerror(987);
        end;
      end;


    function mmx_type(p : pdef) : tmmxtype;
      begin
         mmx_type:=mmxno;
         if is_mmx_able_array(p) then
           begin
              if parraydef(p)^.elementtype.def^.deftype=floatdef then
                case pfloatdef(parraydef(p)^.elementtype.def)^.typ of
                  s32real:
                    mmx_type:=mmxsingle;
                  f16bit:
                    mmx_type:=mmxfixed16
                end
              else
                case porddef(parraydef(p)^.elementtype.def)^.typ of
                   u8bit:
                     mmx_type:=mmxu8bit;
                   s8bit:
                     mmx_type:=mmxs8bit;
                   u16bit:
                     mmx_type:=mmxu16bit;
                   s16bit:
                     mmx_type:=mmxs16bit;
                   u32bit:
                     mmx_type:=mmxu32bit;
                   s32bit:
                     mmx_type:=mmxs32bit;
                end;
           end;
      end;


    function is_mmx_able_array(p : pdef) : boolean;
      begin
{$ifdef SUPPORT_MMX}
         if (cs_mmx_saturation in aktlocalswitches) then
           begin
              is_mmx_able_array:=(p^.deftype=arraydef) and
                not(is_special_array(p)) and
                (
                 (
                  (parraydef(p)^.elementtype.def^.deftype=orddef) and
                  (
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=1) and
                    (porddef(parraydef(p)^.elementtype.def)^.typ in [u32bit,s32bit])
                   )
                   or
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=3) and
                    (porddef(parraydef(p)^.elementtype.def)^.typ in [u16bit,s16bit])
                   )
                  )
                 )
                 or
                (
                 (
                  (parraydef(p)^.elementtype.def^.deftype=floatdef) and
                  (
                   (parraydef(p)^.lowrange=0) and
                   (parraydef(p)^.highrange=3) and
                   (pfloatdef(parraydef(p)^.elementtype.def)^.typ=f16bit)
                  ) or
                  (
                   (parraydef(p)^.lowrange=0) and
                   (parraydef(p)^.highrange=1) and
                   (pfloatdef(parraydef(p)^.elementtype.def)^.typ=s32real)
                  )
                 )
                )
              );
           end
         else
           begin
              is_mmx_able_array:=(p^.deftype=arraydef) and
                (
                 (
                  (parraydef(p)^.elementtype.def^.deftype=orddef) and
                  (
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=1) and
                    (porddef(parraydef(p)^.elementtype.def)^.typ in [u32bit,s32bit])
                   )
                   or
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=3) and
                    (porddef(parraydef(p)^.elementtype.def)^.typ in [u16bit,s16bit])
                   )
                   or
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=7) and
                    (porddef(parraydef(p)^.elementtype.def)^.typ in [u8bit,s8bit])
                   )
                  )
                 )
                 or
                 (
                  (parraydef(p)^.elementtype.def^.deftype=floatdef) and
                  (
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=3) and
                    (pfloatdef(parraydef(p)^.elementtype.def)^.typ=f32bit)
                   )
                   or
                   (
                    (parraydef(p)^.lowrange=0) and
                    (parraydef(p)^.highrange=1) and
                    (pfloatdef(parraydef(p)^.elementtype.def)^.typ=s32real)
                   )
                  )
                 )
                );
           end;
{$else SUPPORT_MMX}
         is_mmx_able_array:=false;
{$endif SUPPORT_MMX}
      end;


    function is_equal(def1,def2 : pdef) : boolean;
      var
         b : boolean;
         hd : pdef;
      begin
         { both types must exists }
         if not (assigned(def1) and assigned(def2)) then
          begin
            is_equal:=false;
            exit;
          end;

         { be sure, that if there is a stringdef, that this is def1 }
         if def2^.deftype=stringdef then
           begin
              hd:=def1;
              def1:=def2;
              def2:=hd;
           end;
         b:=false;

         { both point to the same definition ? }
         if def1=def2 then
           b:=true
         else
         { pointer with an equal definition are equal }
           if (def1^.deftype=pointerdef) and (def2^.deftype=pointerdef) then
             begin
                { here a problem detected in tabsolutesym }
                { the types can be forward type !!        }
                if assigned(def1^.typesym) and (ppointerdef(def1)^.pointertype.def^.deftype=forwarddef) then
                  b:=(def1^.typesym=def2^.typesym)
                else
                  b:=ppointerdef(def1)^.pointertype.def=ppointerdef(def2)^.pointertype.def;
             end
         else
         { ordinals are equal only when the ordinal type is equal }
           if (def1^.deftype=orddef) and (def2^.deftype=orddef) then
             begin
                case porddef(def1)^.typ of
                u8bit,u16bit,u32bit,
                s8bit,s16bit,s32bit:
                  b:=((porddef(def1)^.typ=porddef(def2)^.typ) and
                   (porddef(def1)^.low=porddef(def2)^.low) and
                   (porddef(def1)^.high=porddef(def2)^.high));
                uvoid,uchar,
                bool8bit,bool16bit,bool32bit:
                  b:=(porddef(def1)^.typ=porddef(def2)^.typ);
                end;
             end
         else
           if (def1^.deftype=floatdef) and (def2^.deftype=floatdef) then
             b:=pfloatdef(def1)^.typ=pfloatdef(def2)^.typ
         else
           { strings with the same length are equal }
           if (def1^.deftype=stringdef) and (def2^.deftype=stringdef) and
              (pstringdef(def1)^.string_typ=pstringdef(def2)^.string_typ) then
             begin
                b:=not(is_shortstring(def1)) or
                   (pstringdef(def1)^.len=pstringdef(def2)^.len);
             end
         else
           if (def1^.deftype=formaldef) and (def2^.deftype=formaldef) then
             b:=true
         { file types with the same file element type are equal }
         { this is a problem for assign !!                      }
         { changed to allow if one is untyped                   }
         { all typed files are equal to the special             }
         { typed file that has voiddef as elemnt type           }
         { but must NOT match for text file !!!                 }
         else
            if (def1^.deftype=filedef) and (def2^.deftype=filedef) then
              b:=(pfiledef(def1)^.filetyp=pfiledef(def2)^.filetyp) and
                 ((
                 ((pfiledef(def1)^.typedfiletype.def=nil) and
                  (pfiledef(def2)^.typedfiletype.def=nil)) or
                 (
                  (pfiledef(def1)^.typedfiletype.def<>nil) and
                  (pfiledef(def2)^.typedfiletype.def<>nil) and
                  is_equal(pfiledef(def1)^.typedfiletype.def,pfiledef(def2)^.typedfiletype.def)
                 ) or
                 ( (pfiledef(def1)^.typedfiletype.def=pdef(voiddef)) or
                   (pfiledef(def2)^.typedfiletype.def=pdef(voiddef))
                 )))
         { sets with the same element type are equal }
         else
           if (def1^.deftype=setdef) and (def2^.deftype=setdef) then
             begin
                if assigned(psetdef(def1)^.elementtype.def) and
                   assigned(psetdef(def2)^.elementtype.def) then
                  b:=(psetdef(def1)^.elementtype.def^.deftype=psetdef(def2)^.elementtype.def^.deftype)
                else
                  b:=true;
             end
         else
           if (def1^.deftype=procvardef) and (def2^.deftype=procvardef) then
             begin
                { poassembler isn't important for compatibility }
                { if a method is assigned to a methodpointer    }
                { is checked before                             }
                b:=(pprocvardef(def1)^.proctypeoption=pprocvardef(def2)^.proctypeoption) and
                   (pprocvardef(def1)^.proccalloptions=pprocvardef(def2)^.proccalloptions) and
                   ((pprocvardef(def1)^.procoptions * po_compatibility_options)=
                    (pprocvardef(def2)^.procoptions * po_compatibility_options)) and
                   is_equal(pprocvardef(def1)^.rettype.def,pprocvardef(def2)^.rettype.def) and
                   equal_paras(pprocvardef(def1)^.para,pprocvardef(def2)^.para,false);
             end
         else
           if (def1^.deftype=arraydef) and (def2^.deftype=arraydef) then
             begin
               if is_open_array(def1) or is_open_array(def2) or
                  is_array_of_const(def1) or is_array_of_const(def2) then
                begin
                  if parraydef(def1)^.IsArrayOfConst or parraydef(def2)^.IsArrayOfConst then
                   b:=true
                  else
                   b:=is_equal(parraydef(def1)^.elementtype.def,parraydef(def2)^.elementtype.def);
                end
               else
                begin
                  b:=not(m_tp in aktmodeswitches) and
                     not(m_delphi in aktmodeswitches) and
                     (parraydef(def1)^.lowrange=parraydef(def2)^.lowrange) and
                     (parraydef(def1)^.highrange=parraydef(def2)^.highrange) and
                     is_equal(parraydef(def1)^.elementtype.def,parraydef(def2)^.elementtype.def) and
                     is_equal(parraydef(def1)^.rangetype.def,parraydef(def2)^.rangetype.def);
                end;
             end
         else
           if (def1^.deftype=classrefdef) and (def2^.deftype=classrefdef) then
             begin
                { similar to pointerdef: }
                if assigned(def1^.typesym) and (pclassrefdef(def1)^.pointertype.def^.deftype=forwarddef) then
                  b:=(def1^.typesym=def2^.typesym)
                else
                  b:=is_equal(pclassrefdef(def1)^.pointertype.def,pclassrefdef(def2)^.pointertype.def);
             end;
         is_equal:=b;
      end;


    function is_subequal(def1, def2: pdef): boolean;
      Begin
        is_subequal := false;
        if assigned(def1) and assigned(def2) then
        Begin
          if (def1^.deftype = orddef) and (def2^.deftype = orddef) then
            Begin
              { see p.47 of Turbo Pascal 7.01 manual for the separation of types }
              { range checking for case statements is done with testrange        }
              case porddef(def1)^.typ of
                u8bit,u16bit,u32bit,
                s8bit,s16bit,s32bit :
                  is_subequal:=(porddef(def2)^.typ in [s32bit,u32bit,u8bit,s8bit,s16bit,u16bit]);
                bool8bit,bool16bit,bool32bit :
                  is_subequal:=(porddef(def2)^.typ in [bool8bit,bool16bit,bool32bit]);
                uchar :
                  is_subequal:=(porddef(def2)^.typ=uchar);
              end;
            end
          else
            Begin
              { I assume that both enumerations are equal when the first }
              { pointers are equal.                                      }
              if (def1^.deftype = enumdef) and (def2^.deftype =enumdef) then
                Begin
                  if penumdef(def1)^.firstenum = penumdef(def2)^.firstenum then
                     is_subequal := TRUE;
                end;
            end;
        end; { endif assigned ... }
      end;

    function CheckTypes(def1,def2 : pdef) : boolean;

      var
         s1,s2 : string;

      begin
        if not is_equal(def1,def2) then
         begin
           { Crash prevention }
           if (not assigned(def1)) or (not assigned(def2)) then
             Message(type_e_mismatch)
           else
             begin
                s1:=def1^.typename;
                s2:=def2^.typename;
                if (s1<>'<unknown type>') and (s2<>'<unknown type>') then
                  Message2(type_e_not_equal_types,def1^.typename,def2^.typename)
                else
                  Message(type_e_mismatch);
             end;
           CheckTypes:=false;
         end
        else
         CheckTypes:=true;
      end;

end.
{
  $Log$
  Revision 1.97  2000-02-09 13:23:09  peter
    * log truncated

  Revision 1.96  2000/02/01 09:44:03  peter
    * is_voidpointer

  Revision 1.95  2000/01/07 01:14:49  peter
    * updated copyright to 2000

  Revision 1.94  2000/01/04 16:35:58  jonas
    * when range checking is off, constants that are out of bound are no longer
      truncated to their max/min legal value but left alone (jsut an "and" is done to
      make sure they fit in the allocated space if necessary)

  Revision 1.93  1999/12/31 14:26:28  peter
    * fixed crash with empty array constructors

  Revision 1.92  1999/11/30 10:40:59  peter
    + ttype, tsymlist

  Revision 1.91  1999/11/06 14:34:31  peter
    * truncated log to 20 revs

  Revision 1.90  1999/10/26 12:30:46  peter
    * const parameter is now checked
    * better and generic check if a node can be used for assigning
    * export fixes
    * procvar equal works now (it never had worked at least from 0.99.8)
    * defcoll changed to linkedlist with pparaitem so it can easily be
      walked both directions

  Revision 1.89  1999/10/01 10:04:07  peter
    * fixed is_equal for proc -> procvar which didn't check the
      callconvention and type anymore since the splitting of procoptions

  Revision 1.88  1999/10/01 08:02:51  peter
    * forward type declaration rewritten

  Revision 1.87  1999/09/15 22:09:27  florian
    + rtti is now automatically generated for published classes, i.e.
      they are handled like an implicit property

  Revision 1.86  1999/09/11 09:08:35  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 1.85  1999/08/13 21:27:08  peter
    * more fixes for push_addr

  Revision 1.84  1999/08/13 15:38:23  peter
    * fixed push_addr_param for records < 4, the array high<low range check
      broke this code.

  Revision 1.83  1999/08/07 14:21:06  florian
    * some small problems fixed

  Revision 1.82  1999/08/07 13:36:56  daniel
  * Recommitted the arraydef overflow bugfix.

  Revision 1.80  1999/08/05 22:42:49  daniel
  * Fixed potential bug for open arrays (Their size is not known at
    compilation time).

  Revision 1.79  1999/08/03 22:03:41  peter
    * moved bitmask constants to sets
    * some other type/const renamings

  Revision 1.78  1999/07/30 12:26:42  peter
    * array is_equal disabled for tp,delphi mode

  Revision 1.77  1999/07/29 11:41:51  peter
    * array is_equal extended

  Revision 1.76  1999/07/27 23:39:15  peter
    * open array checks also for s32bitdef, because u32bit also has a
      high range of -1

}