freepascal.compiler/compiler/ptype.pas

{
    Copyright (c) 1998-2002 by Florian Klaempfl

    Does parsing types for Free Pascal

    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 ptype;

{$i fpcdefs.inc}

interface

    uses
       globtype,cclasses,symtype,symdef;

    const
       { forward types should only be possible inside a TYPE statement }
       typecanbeforward : boolean = false;

    var
       { hack, which allows to use the current parsed }
       { object type as function argument type  }
       testcurobject : byte;

    { reads a string, file type or a type id and returns a name and }
    { tdef }
    procedure single_type(var def:tdef;isforwarddef:boolean);

    procedure read_named_type(var def:tdef;const name : TIDString;genericdef:tstoreddef;genericlist:TFPObjectList;parseprocvardir:boolean);
    procedure read_anon_type(var def : tdef;parseprocvardir:boolean);

    { reads a type definition }
    { to a appropriating tdef, s gets the name of   }
    { the type to allow name mangling          }
    procedure id_type(var def : tdef;isforwarddef:boolean);


implementation

    uses
       { common }
       cutils,
       { global }
       globals,tokens,verbose,
       systems,
       { target }
       paramgr,
       { symtable }
       symconst,symbase,symsym,symtable,
       defutil,defcmp,
       { pass 1 }
       node,
       nmat,nadd,ncal,nset,ncnv,ninl,ncon,nld,nflw,
       { parser }
       scanner,
       pbase,pexpr,pdecsub,pdecvar,pdecobj;


    procedure generate_specialization(var pt1:tnode;const name:string);
      var
        st  : TSymtable;
        pt2 : tnode;
        first,
        err : boolean;
        i   : longint;
        sym : tsym;
        genericdef : tstoreddef;
        generictype : ttypesym;
        generictypelist : TFPObjectList;
      begin
        { retrieve generic def that we are going to replace }
        genericdef:=tstoreddef(pt1.resultdef);
        pt1.resultdef:=nil;
        if not(df_generic in genericdef.defoptions) then
          begin
            Comment(V_Error,'Specialization is only supported for generic types');
            pt1.resultdef:=generrordef;
            { recover }
            consume(_LSHARPBRACKET);
            repeat
              pt2:=factor(false);
              pt2.free;
            until not try_to_consume(_COMMA);
            consume(_RSHARPBRACKET);
            exit;
          end;
        consume(_LSHARPBRACKET);
        block_type:=bt_specialize;
        { Parse generic parameters, for each undefineddef in the symtable of
          the genericdef we need to have a new def }
        err:=false;
        first:=true;
        generictypelist:=TFPObjectList.create(false);
        case genericdef.typ of
          procdef :
            st:=genericdef.GetSymtable(gs_para);
          objectdef,
          recorddef :
            st:=genericdef.GetSymtable(gs_record);
        end;
        if not assigned(st) then
          internalerror(200511182);
        for i:=0 to st.SymList.Count-1 do
          begin
            sym:=tsym(st.SymList[i]);
            if (sym.typ=typesym) and
               (ttypesym(sym).typedef.typ=undefineddef) then
              begin
                if not first then
                  begin
                    consume(_COMMA);
                    first:=false;
                  end;
                pt2:=factor(false);
                if pt2.nodetype=typen then
                  begin
                    generictype:=ttypesym.create(sym.realname,pt2.resultdef);
                    generictypelist.add(generictype);
                  end
                else
                  begin
                    Message(type_e_type_id_expected);
                    err:=true;
                  end;
                pt2.free;
              end;
          end;
        { Reparse the original type definition }
        if not err then
          begin
            if not assigned(genericdef.generictokenbuf) then
              internalerror(200511171);
            current_scanner.startreplaytokens(genericdef.generictokenbuf);
            read_named_type(pt1.resultdef,name,genericdef,generictypelist,false);
            { Consume the semicolon if it is also recorded }
            try_to_consume(_SEMICOLON);
          end;
        generictypelist.free;
        consume(_RSHARPBRACKET);
      end;


    procedure id_type(var def : tdef;isforwarddef:boolean);
    { reads a type definition }
    { to a appropriating tdef, s gets the name of   }
    { the type to allow name mangling          }
      var
        is_unit_specific : boolean;
        pos : tfileposinfo;
        srsym : tsym;
        srsymtable : TSymtable;
        s,sorg : TIDString;
      begin
         s:=pattern;
         sorg:=orgpattern;
         pos:=current_tokenpos;
         { use of current parsed object:
            - classes can be used also in classes
            - objects can be parameters }
         if assigned(aktobjectdef) and
            (aktobjectdef.objname^=pattern) and
            (
             (testcurobject=2) or
             is_class_or_interface(aktobjectdef)
            )then
           begin
             consume(_ID);
             def:=aktobjectdef;
             exit;
           end;
         { Use the special searchsym_type that ignores records,objects and
           parameters }
         searchsym_type(s,srsym,srsymtable);
         { handle unit specification like System.Writeln }
         is_unit_specific:=try_consume_unitsym(srsym,srsymtable);
         consume(_ID);
         { Types are first defined with an error def before assigning
           the real type so check if it's an errordef. if so then
           give an error. Only check for typesyms in the current symbol
           table as forwarddef are not resolved directly }
         if assigned(srsym) and
            (srsym.typ=typesym) and
            (ttypesym(srsym).typedef.typ=errordef) then
          begin
            Message1(type_e_type_is_not_completly_defined,ttypesym(srsym).realname);
            def:=generrordef;
            exit;
          end;
         { are we parsing a possible forward def ? }
         if isforwarddef and
            not(is_unit_specific) then
          begin
            def:=tforwarddef.create(s,pos);
            exit;
          end;
         { unknown sym ? }
         if not assigned(srsym) then
          begin
            Message1(sym_e_id_not_found,sorg);
            def:=generrordef;
            exit;
          end;
         { type sym ? }
         if (srsym.typ<>typesym) then
          begin
            Message(type_e_type_id_expected);
            def:=generrordef;
            exit;
          end;
         { Give an error when referring to an errordef }
         if (ttypesym(srsym).typedef.typ=errordef) then
          begin
            Message(sym_e_error_in_type_def);
            def:=generrordef;
            exit;
          end;
        def:=ttypesym(srsym).typedef;
      end;


    procedure single_type(var def:tdef;isforwarddef:boolean);
       var
         t2 : tdef;
         again : boolean;
       begin
         repeat
           again:=false;
             case token of
               _STRING:
                 string_dec(def);

               _FILE:
                 begin
                    consume(_FILE);
                    if try_to_consume(_OF) then
                      begin
                         single_type(t2,false);
                         def:=tfiledef.createtyped(t2);
                      end
                    else
                      def:=cfiletype;
                 end;

               _ID:
                 begin
                   if try_to_consume(_SPECIALIZE) then
                     begin
                       block_type:=bt_specialize;
                       again:=true;
                     end
                   else
                     id_type(def,isforwarddef);
                 end;

               else
                 begin
                   message(type_e_type_id_expected);
                   def:=generrordef;
                 end;
            end;
        until not again;
      end;

    { reads a record declaration }
    function record_dec : tdef;

      var
         recst : trecordsymtable;
         storetypecanbeforward : boolean;
         old_object_option : tsymoptions;
      begin
         { create recdef }
         recst:=trecordsymtable.create(current_settings.packrecords);
         record_dec:=trecorddef.create(recst);
         { insert in symtablestack }
         symtablestack.push(recst);
         { parse record }
         consume(_RECORD);
         old_object_option:=current_object_option;
         current_object_option:=[sp_public];
         storetypecanbeforward:=typecanbeforward;
         { for tp7 don't allow forward types }
         if m_tp7 in current_settings.modeswitches then
           typecanbeforward:=false;
         read_record_fields([vd_record]);
         consume(_END);
         typecanbeforward:=storetypecanbeforward;
         current_object_option:=old_object_option;
         { make the record size aligned }
         recst.addalignmentpadding;
         { restore symtable stack }
         symtablestack.pop(recst);
         if trecorddef(record_dec).is_packed and
            record_dec.needs_inittable then
           Message(type_e_no_packed_inittable);
      end;


    { reads a type definition and returns a pointer to it }
    procedure read_named_type(var def : tdef;const name : TIDString;genericdef:tstoreddef;genericlist:TFPObjectList;parseprocvardir:boolean);
      var
        pt : tnode;
        tt2 : tdef;
        aktenumdef : tenumdef;
        s : TIDString;
        l,v : TConstExprInt;
        oldpackrecords : longint;
        defpos,storepos : tfileposinfo;

        procedure expr_type;
        var
           pt1,pt2 : tnode;
           lv,hv   : TConstExprInt;
           old_block_type : tblock_type;
        begin
           old_block_type:=block_type;
           { use of current parsed object:
              - classes can be used also in classes
              - objects can be parameters }
           if (token=_ID) and
              assigned(aktobjectdef) and
              (aktobjectdef.objname^=pattern) and
              (
               (testcurobject=2) or
               is_class_or_interface(aktobjectdef)
              )then
             begin
               consume(_ID);
               def:=aktobjectdef;
               exit;
             end;
           { Generate a specialization? }
           if try_to_consume(_SPECIALIZE) then
             block_type:=bt_specialize;
           { we can't accept a equal in type }
           pt1:=comp_expr(not(ignore_equal));
           if (block_type<>bt_specialize) and
              try_to_consume(_POINTPOINT) then
             begin
               { get high value of range }
               pt2:=comp_expr(not(ignore_equal));
               { make both the same type or give an error. This is not
                 done when both are integer values, because typecasting
                 between -3200..3200 will result in a signed-unsigned
                 conflict and give a range check error (PFV) }
               if not(is_integer(pt1.resultdef) and is_integer(pt2.resultdef)) then
                 inserttypeconv(pt1,pt2.resultdef);
               { both must be evaluated to constants now }
               if (pt1.nodetype=ordconstn) and
                  (pt2.nodetype=ordconstn) then
                 begin
                   lv:=tordconstnode(pt1).value;
                   hv:=tordconstnode(pt2).value;
                   { Check bounds }
                   if hv<lv then
                     Message(parser_e_upper_lower_than_lower)
                   else
                     begin
                       { All checks passed, create the new def }
                       case pt1.resultdef.typ of
                         enumdef :
                           def:=tenumdef.create_subrange(tenumdef(pt1.resultdef),lv,hv);
                         orddef :
                           begin
                             if is_char(pt1.resultdef) then
                               def:=torddef.create(uchar,lv,hv)
                             else
                               if is_boolean(pt1.resultdef) then
                                 def:=torddef.create(bool8bit,lv,hv)
                               else
                                 def:=torddef.create(range_to_basetype(lv,hv),lv,hv);
                           end;
                       end;
                     end;
                 end
               else
                 Message(sym_e_error_in_type_def);
               pt2.free;
             end
           else
             begin
               { a simple type renaming or generic specialization }
               if (pt1.nodetype=typen) then
                 begin
                   if (block_type=bt_specialize) then
                     generate_specialization(pt1,name);
                   def:=ttypenode(pt1).resultdef;
                 end
               else
                 Message(sym_e_error_in_type_def);
             end;
           pt1.free;
           block_type:=old_block_type;
        end;


      procedure set_dec;
        begin
          consume(_SET);
          consume(_OF);
          read_anon_type(tt2,true);
          if assigned(tt2) then
           begin
             case tt2.typ of
               { don't forget that min can be negativ  PM }
               enumdef :
                 if tenumdef(tt2).min>=0 then
                  // !! def:=tsetdef.create(tt2,tenumdef(tt2.def).min,tenumdef(tt2.def).max))
                  def:=tsetdef.create(tt2,tenumdef(tt2).max)
                 else
                  Message(sym_e_ill_type_decl_set);
               orddef :
                 begin
                   if (torddef(tt2).ordtype<>uvoid) and
                      (torddef(tt2).low>=0) then
                     // !! def:=tsetdef.create(tt2,torddef(tt2.def).low,torddef(tt2.def).high))
                     def:=tsetdef.create(tt2,torddef(tt2).high)
                   else
                     Message(sym_e_ill_type_decl_set);
                 end;
               else
                 Message(sym_e_ill_type_decl_set);
             end;
           end
          else
           def:=generrordef;
        end;


      procedure array_dec(is_packed: boolean);
        var
          lowval,
          highval   : TConstExprInt;
          indexdef  : tdef;
          hdef      : tdef;
          arrdef    : tarraydef;

          procedure setdefdecl(def:tdef);
          begin
            case def.typ of
              enumdef :
                begin
                  lowval:=tenumdef(def).min;
                  highval:=tenumdef(def).max;
                  if (m_fpc in current_settings.modeswitches) and
                     (tenumdef(def).has_jumps) then
                   Message(type_e_array_index_enums_with_assign_not_possible);
                  indexdef:=def;
                end;
              orddef :
                begin
                  if torddef(def).ordtype in [uchar,
                    u8bit,u16bit,
                    s8bit,s16bit,s32bit,
{$ifdef cpu64bit}
                    u32bit,s64bit,
{$endif cpu64bit}
                    bool8bit,bool16bit,bool32bit,bool64bit,
                    uwidechar] then
                    begin
                       lowval:=torddef(def).low;
                       highval:=torddef(def).high;
                       indexdef:=def;
                    end
                  else
                    Message1(parser_e_type_cant_be_used_in_array_index,def.GetTypeName);
                end;
              else
                Message(sym_e_error_in_type_def);
            end;
          end;

        begin
           arrdef:=nil;
           consume(_ARRAY);
           { open array? }
           if try_to_consume(_LECKKLAMMER) then
             begin
                { defaults }
                indexdef:=generrordef;
                lowval:=low(aint);
                highval:=high(aint);
                repeat
                  { read the expression and check it, check apart if the
                    declaration is an enum declaration because that needs to
                    be parsed by readtype (PFV) }
                  if token=_LKLAMMER then
                   begin
                     read_anon_type(hdef,true);
                     setdefdecl(hdef);
                   end
                  else
                   begin
                     pt:=expr;
                     if pt.nodetype=typen then
                      setdefdecl(pt.resultdef)
                     else
                       begin
                          if (pt.nodetype=rangen) then
                           begin
                             if (trangenode(pt).left.nodetype=ordconstn) and
                                (trangenode(pt).right.nodetype=ordconstn) then
                              begin
                                { make both the same type or give an error. This is not
                                  done when both are integer values, because typecasting
                                  between -3200..3200 will result in a signed-unsigned
                                  conflict and give a range check error (PFV) }
                                if not(is_integer(trangenode(pt).left.resultdef) and is_integer(trangenode(pt).left.resultdef)) then
                                  inserttypeconv(trangenode(pt).left,trangenode(pt).right.resultdef);
                                lowval:=tordconstnode(trangenode(pt).left).value;
                                highval:=tordconstnode(trangenode(pt).right).value;
                                if highval<lowval then
                                 begin
                                   Message(parser_e_array_lower_less_than_upper_bound);
                                   highval:=lowval;
                                 end
                                else if (lowval < low(aint)) or
                                        (highval > high(aint)) then
                                  begin
                                    Message(parser_e_array_range_out_of_bounds);
                                    lowval :=0;
                                    highval:=0;
                                  end;
                                if is_integer(trangenode(pt).left.resultdef) then
                                  range_to_type(lowval,highval,indexdef)
                                else
                                  indexdef:=trangenode(pt).left.resultdef;
                              end
                             else
                              Message(type_e_cant_eval_constant_expr);
                           end
                          else
                           Message(sym_e_error_in_type_def)
                       end;
                     pt.free;
                   end;

                  { if the array is already created add the new arrray
                    as element of the existing array, otherwise create a new array }
                  if assigned(arrdef) then
                    begin
                      arrdef.elementdef:=tarraydef.create(lowval,highval,indexdef);
                      arrdef:=tarraydef(arrdef.elementdef);
                    end
                  else
                    begin
                      arrdef:=tarraydef.create(lowval,highval,indexdef);
                      def:=arrdef;
                    end;
                  if is_packed then
                    include(arrdef.arrayoptions,ado_IsBitPacked);

                  if token=_COMMA then
                    consume(_COMMA)
                  else
                    break;
                until false;
                consume(_RECKKLAMMER);
             end
           else
             begin
                if is_packed then
                  Message(parser_e_packed_dynamic_open_array);
                arrdef:=tarraydef.create(0,-1,s32inttype);
                include(arrdef.arrayoptions,ado_IsDynamicArray);
                def:=arrdef;
             end;
           consume(_OF);
           read_anon_type(tt2,true);
           { set element type of the last array definition }
           if assigned(arrdef) then
             begin
               arrdef.elementdef:=tt2;
               if is_packed and
                  tt2.needs_inittable then
                 Message(type_e_no_packed_inittable);
             end;
        end;

      var
        p  : tnode;
        pd : tabstractprocdef;
        is_func,
        enumdupmsg, first : boolean;
        newtype    : ttypesym;
        oldlocalswitches : tlocalswitches;
        bitpacking: boolean;
      begin
         def:=nil;
         case token of
            _STRING,_FILE:
              begin
                single_type(def,false);
              end;
           _LKLAMMER:
              begin
                consume(_LKLAMMER);
                first := true;
                { allow negativ value_str }
                l:=-1;
                enumdupmsg:=false;
                aktenumdef:=tenumdef.create;
                repeat
                  s:=orgpattern;
                  defpos:=current_tokenpos;
                  consume(_ID);
                  { only allow assigning of specific numbers under fpc mode }
                  if not(m_tp7 in current_settings.modeswitches) and
                     (
                      { in fpc mode also allow := to be compatible
                        with previous 1.0.x versions }
                      ((m_fpc in current_settings.modeswitches) and
                       try_to_consume(_ASSIGNMENT)) or
                      try_to_consume(_EQUAL)
                     ) then
                    begin
                       oldlocalswitches:=current_settings.localswitches;
                       include(current_settings.localswitches,cs_allow_enum_calc);
                       p:=comp_expr(true);
                       current_settings.localswitches:=oldlocalswitches;
                       if (p.nodetype=ordconstn) then
                        begin
                          { we expect an integer or an enum of the
                            same type }
                          if is_integer(p.resultdef) or
                             is_char(p.resultdef) or
                             equal_defs(p.resultdef,aktenumdef) then
                           v:=tordconstnode(p).value
                          else
                           IncompatibleTypes(p.resultdef,s32inttype);
                        end
                       else
                        Message(parser_e_illegal_expression);
                       p.free;
                       { please leave that a note, allows type save }
                       { declarations in the win32 units ! }
                       if (not first) and (v<=l) and (not enumdupmsg) then
                        begin
                          Message(parser_n_duplicate_enum);
                          enumdupmsg:=true;
                        end;
                       l:=v;
                    end
                  else
                    inc(l);
                  first := false;
                  storepos:=current_tokenpos;
                  current_tokenpos:=defpos;
                  tstoredsymtable(aktenumdef.owner).insert(tenumsym.create(s,aktenumdef,l));
                  current_tokenpos:=storepos;
                until not try_to_consume(_COMMA);
                def:=aktenumdef;
                consume(_RKLAMMER);
              end;
            _ARRAY:
              begin
                array_dec(false);
              end;
            _SET:
              begin
                set_dec;
              end;
           _CARET:
              begin
                consume(_CARET);
                single_type(tt2,typecanbeforward);
                def:=tpointerdef.create(tt2);
              end;
            _RECORD:
              begin
                def:=record_dec;
              end;
            _PACKED,
            _BITPACKED:
              begin
                bitpacking :=
                  (cs_bitpacking in current_settings.localswitches) or
                  (token = _BITPACKED);
                consume(token);
                if token=_ARRAY then
                  array_dec(bitpacking)
                else if token=_SET then
                  set_dec
                else
                  begin
                    oldpackrecords:=current_settings.packrecords;
                    if (not bitpacking) or
                       (token in [_CLASS,_OBJECT]) then
                      current_settings.packrecords:=1
                    else
                      current_settings.packrecords:=bit_alignment;
                    if token in [_CLASS,_OBJECT] then
                      def:=object_dec(name,genericdef,genericlist,nil)
                    else
                      def:=record_dec;
                    current_settings.packrecords:=oldpackrecords;
                  end;
              end;
            _DISPINTERFACE,
            _CLASS,
            _CPPCLASS,
            _INTERFACE,
            _OBJECT:
              begin
                def:=object_dec(name,genericdef,genericlist,nil);
              end;
            _PROCEDURE,
            _FUNCTION:
              begin
                is_func:=(token=_FUNCTION);
                consume(token);
                pd:=tprocvardef.create(normal_function_level);
                if token=_LKLAMMER then
                  parse_parameter_dec(pd);
                if is_func then
                 begin
                   consume(_COLON);
                   single_type(pd.returndef,false);
                 end;
                if token=_OF then
                  begin
                    consume(_OF);
                    consume(_OBJECT);
                    include(pd.procoptions,po_methodpointer);
                  end;
                def:=pd;
                { possible proc directives }
                if parseprocvardir then
                  begin
                    if 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;
                      end;
                    { Add implicit hidden parameters and function result }
                    handle_calling_convention(pd);
                  end;
              end;
            else
              expr_type;
         end;
         if def=nil then
          def:=generrordef;
      end;


    procedure read_anon_type(var def : tdef;parseprocvardir:boolean);
      begin
        read_named_type(def,'',nil,nil,parseprocvardir);
      end;


end.