fpc/compiler/nmem.pas

{
    $Id$
    Copyright (c) 2000-2002 by Florian Klaempfl

    Type checking and register allocation for memory related 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.

 ****************************************************************************
}
unit nmem;

{$i fpcdefs.inc}

interface

    uses
       node,
       symtype,symdef,symsym,symtable,
       cpubase;

    type
       tloadvmtnode = class(tunarynode)
          constructor create(l : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       tloadvmtnodeclass = class of tloadvmtnode;

       thnewnode = class(tnode)
          objtype : ttype;
          constructor create(t:ttype);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       thnewnodeclass = class of thnewnode;

       thdisposenode = class(tunarynode)
          constructor create(l : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       thdisposenodeclass = class of thdisposenode;

       taddrnode = class(tunarynode)
          getprocvardef : tprocvardef;
          constructor create(l : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       taddrnodeclass = class of taddrnode;

       tdoubleaddrnode = class(tunarynode)
          constructor create(l : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       tdoubleaddrnodeclass = class of tdoubleaddrnode;

       tderefnode = class(tunarynode)
          constructor create(l : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       tderefnodeclass = class of tderefnode;

       tsubscriptnode = class(tunarynode)
          vs : tvarsym;
          constructor create(varsym : tsym;l : tnode);virtual;
          function getcopy : tnode;override;
          function pass_1 : tnode;override;
          function docompare(p: tnode): boolean; override;
          function det_resulttype:tnode;override;
       end;
       tsubscriptnodeclass = class of tsubscriptnode;

       tvecnode = class(tbinarynode)
          constructor create(l,r : tnode);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       tvecnodeclass = class of tvecnode;

       tselfnode = class(tnode)
          classdef : tdef; { objectdef or classrefdef }
          constructor create(_class : tdef);virtual;
          function pass_1 : tnode;override;
          function det_resulttype:tnode;override;
       end;
       tselfnodeclass = class of tselfnode;

       twithnode = class(tbinarynode)
          withsymtable  : twithsymtable;
          tablecount    : longint;
          withreference : treference;
          constructor create(symtable : twithsymtable;l,r : tnode;count : longint);virtual;
          destructor destroy;override;
          function getcopy : tnode;override;
          function pass_1 : tnode;override;
          function docompare(p: tnode): boolean; override;
          function det_resulttype:tnode;override;
       end;
       twithnodeclass = class of twithnode;

    var
       cloadvmtnode : tloadvmtnodeclass;
       chnewnode : thnewnodeclass;
       chdisposenode : thdisposenodeclass;
       caddrnode : taddrnodeclass;
       cdoubleaddrnode : tdoubleaddrnodeclass;
       cderefnode : tderefnodeclass;
       csubscriptnode : tsubscriptnodeclass;
       cvecnode : tvecnodeclass;
       cselfnode : tselfnodeclass;
       cwithnode : twithnodeclass;

implementation

    uses
      globtype,systems,
      cutils,verbose,globals,
      symconst,symbase,defbase,
      nbas,
      htypechk,pass_1,ncal,nld,ncon,ncnv,cgbase
      ;

{*****************************************************************************
                            TLOADVMTNODE
*****************************************************************************}

    constructor tloadvmtnode.create(l : tnode);
      begin
         inherited create(loadvmtn,l);
      end;

    function tloadvmtnode.det_resulttype:tnode;
      begin
        result:=nil;
        resulttypepass(left);
        if codegenerror then
         exit;

        resulttype.setdef(tclassrefdef.create(left.resulttype));
      end;

    function tloadvmtnode.pass_1 : tnode;
      begin
         result:=nil;
         registers32:=1;
         location.loc:=LOC_REGISTER;
      end;

{*****************************************************************************
                             THNEWNODE
*****************************************************************************}

    constructor thnewnode.create(t:ttype);
      begin
         inherited create(hnewn);
         objtype:=t;
      end;


    function thnewnode.det_resulttype:tnode;
      begin
        result:=nil;
        if objtype.def.deftype<>objectdef then
          Message(parser_e_pointer_to_class_expected);
        resulttype:=objtype;
      end;


    function thnewnode.pass_1 : tnode;
      begin
         result:=nil;
      end;


{*****************************************************************************
                            THDISPOSENODE
*****************************************************************************}

    constructor thdisposenode.create(l : tnode);
      begin
         inherited create(hdisposen,l);
      end;


    function thdisposenode.det_resulttype:tnode;
      begin
        result:=nil;
        resulttypepass(left);
        if codegenerror then
         exit;
        if (left.resulttype.def.deftype<>pointerdef) then
          CGMessage1(type_e_pointer_type_expected,left.resulttype.def.typename);
        resulttype:=tpointerdef(left.resulttype.def).pointertype;
      end;


    function thdisposenode.pass_1 : tnode;
      begin
         result:=nil;
         firstpass(left);
         if codegenerror then
           exit;

         registers32:=left.registers32;
         registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
         registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}
         if registers32<1 then
           registers32:=1;
         {
         if left.location.loc<>LOC_REFERENCE then
           CGMessage(cg_e_illegal_expression);
         }
         if left.location.loc=LOC_CREGISTER then
           inc(registers32);
         location.loc:=LOC_REFERENCE;
      end;


{*****************************************************************************
                             TADDRNODE
*****************************************************************************}

    constructor taddrnode.create(l : tnode);

      begin
         inherited create(addrn,l);
      end;


    function taddrnode.det_resulttype:tnode;
      var
         hp  : tnode;
         hp2 : TParaItem;
         hp3 : tabstractprocdef;
      begin
        result:=nil;
        resulttypepass(left);
        if codegenerror then
         exit;

        { don't allow constants }
        if is_constnode(left) then
         begin
           aktfilepos:=left.fileinfo;
           CGMessage(type_e_no_addr_of_constant);
           exit;
         end;

        { tp @procvar support (type of @procvar is a void pointer)
          Note: we need to leave the addrn in the tree,
          else we can't see the difference between @procvar and procvar.
          we set the procvarload flag so a secondpass does nothing for
          this node (PFV) }
        if (m_tp_procvar in aktmodeswitches) then
         begin
           case left.nodetype of
             calln :
               begin
                 { a load of a procvar can't have parameters }
                 if assigned(tcallnode(left).left) then
                   CGMessage(cg_e_illegal_expression);
                 { is it a procvar? }
                 hp:=tcallnode(left).right;
                 if assigned(hp) then
                   begin
                     { remove calln node }
                     tcallnode(left).right:=nil;
                     left.free;
                     left:=hp;
                     include(flags,nf_procvarload);
                   end;
               end;
             loadn,
             subscriptn,
             typeconvn,
             vecn,
             derefn :
               begin
                 if left.resulttype.def.deftype=procvardef then
                   include(flags,nf_procvarload);
               end;
           end;
           if nf_procvarload in flags then
            begin
              resulttype:=voidpointertype;
              exit;
            end;
         end;

        { proc 2 procvar ? }
        if left.nodetype=calln then
         { if it were a valid construct, the addr node would already have }
         { been removed in the parser. This happens for (in FPC mode)     }
         { procvar1 := @procvar2(parameters);                             }
         CGMessage(cg_e_illegal_expression)
        else
         if (left.nodetype=loadn) and (tloadnode(left).symtableentry.typ=procsym) then
          begin
            { the address is already available when loading a procedure of object }
            if assigned(tloadnode(left).left) then
             include(flags,nf_procvarload);

            { result is a procedure variable }
            { No, to be TP compatible, you must return a voidpointer to
              the procedure that is stored in the procvar.}
            if not(m_tp_procvar in aktmodeswitches) then
              begin
                 if assigned(getprocvardef) then
                  hp3:=getprocvardef
                 else
                  hp3:=tabstractprocdef(tprocsym(tloadnode(left).symtableentry).defs^.def);

                 { create procvardef }
                 resulttype.setdef(tprocvardef.create);
                 tprocvardef(resulttype.def).proctypeoption:=hp3.proctypeoption;
                 tprocvardef(resulttype.def).proccalloption:=hp3.proccalloption;
                 tprocvardef(resulttype.def).procoptions:=hp3.procoptions;
                 tprocvardef(resulttype.def).rettype:=hp3.rettype;
                 tprocvardef(resulttype.def).symtablelevel:=hp3.symtablelevel;

                 { method ? then set the methodpointer flag }
                 if (hp3.owner.symtabletype=objectsymtable) then
                   include(tprocvardef(resulttype.def).procoptions,po_methodpointer);

                 { we need to process the parameters reverse so they are inserted
                   in the correct right2left order (PFV) }
                 hp2:=TParaItem(hp3.Para.last);
                 while assigned(hp2) do
                   begin
                      tprocvardef(resulttype.def).concatpara(hp2.paratype,hp2.parasym,hp2.paratyp,hp2.defaultvalue);
                      hp2:=TParaItem(hp2.previous);
                   end;
              end
            else
              resulttype:=voidpointertype;
          end
        else
          begin
            { what are we getting the address from an absolute sym? }
            hp:=left;
            while assigned(hp) and (hp.nodetype in [vecn,derefn,subscriptn]) do
             hp:=tunarynode(hp).left;
            if assigned(hp) and (hp.nodetype=loadn) and
               ((tloadnode(hp).symtableentry.typ=absolutesym) and
                tabsolutesym(tloadnode(hp).symtableentry).absseg) then
             begin
               if not(cs_typed_addresses in aktlocalswitches) then
                 resulttype:=voidfarpointertype
               else
                 resulttype.setdef(tpointerdef.createfar(left.resulttype));
             end
            else
             begin
               if not(cs_typed_addresses in aktlocalswitches) then
                 resulttype:=voidpointertype
               else
                 resulttype.setdef(tpointerdef.create(left.resulttype));
             end;
          end;

         { this is like the function addr }
         inc(parsing_para_level);
         set_varstate(left,false);
         dec(parsing_para_level);

      end;


    function taddrnode.pass_1 : tnode;
      begin
         result:=nil;
         firstpass(left);
         if codegenerror then
          exit;

         make_not_regable(left);
         if nf_procvarload in flags then
          begin
            registers32:=left.registers32;
            registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
            registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}
            if registers32<1 then
             registers32:=1;
            location.loc:=left.location.loc;
            exit;
          end;

         { we should allow loc_mem for @string }
         if not(left.location.loc in [LOC_CREFERENCE,LOC_REFERENCE]) then
           begin
             aktfilepos:=left.fileinfo;
             CGMessage(cg_e_illegal_expression);
           end;

         registers32:=left.registers32;
         registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
         registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}
         if registers32<1 then
           registers32:=1;
         { is this right for object of methods ?? }
         location.loc:=LOC_REGISTER;
      end;


{*****************************************************************************
                           TDOUBLEADDRNODE
*****************************************************************************}

    constructor tdoubleaddrnode.create(l : tnode);
      begin
         inherited create(doubleaddrn,l);
      end;


    function tdoubleaddrnode.det_resulttype:tnode;
      begin
        result:=nil;
         resulttypepass(left);
         if codegenerror then
          exit;

         inc(parsing_para_level);
         set_varstate(left,false);
         dec(parsing_para_level);

         if (left.resulttype.def.deftype)<>procvardef then
           CGMessage(cg_e_illegal_expression);

         resulttype:=voidpointertype;
      end;


    function tdoubleaddrnode.pass_1 : tnode;
      begin
         result:=nil;
         make_not_regable(left);
         firstpass(left);
         if codegenerror then
           exit;

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

         registers32:=left.registers32;
         registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
         registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}
         if registers32<1 then
           registers32:=1;
         location.loc:=LOC_REGISTER;
      end;


{*****************************************************************************
                             TDEREFNODE
*****************************************************************************}

    constructor tderefnode.create(l : tnode);

      begin
         inherited create(derefn,l);

      end;

    function tderefnode.det_resulttype:tnode;
      begin
         result:=nil;
         resulttypepass(left);
         set_varstate(left,true);
         if codegenerror then
          exit;

         if left.resulttype.def.deftype=pointerdef then
          resulttype:=tpointerdef(left.resulttype.def).pointertype
         else
          CGMessage(cg_e_invalid_qualifier);
      end;

    function tderefnode.pass_1 : tnode;
      begin
         result:=nil;
         firstpass(left);
         if codegenerror then
          exit;

         registers32:=max(left.registers32,1);
         registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
         registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}

         location.loc:=LOC_REFERENCE;
      end;


{*****************************************************************************
                            TSUBSCRIPTNODE
*****************************************************************************}

    constructor tsubscriptnode.create(varsym : tsym;l : tnode);

      begin
         inherited create(subscriptn,l);
         { vs should be changed to tsym! }
         vs:=tvarsym(varsym);
      end;

    function tsubscriptnode.getcopy : tnode;

      var
         p : tsubscriptnode;

      begin
         p:=tsubscriptnode(inherited getcopy);
         p.vs:=vs;
         getcopy:=p;
      end;


    function tsubscriptnode.det_resulttype:tnode;
      begin
        result:=nil;
        resulttypepass(left);
        resulttype:=vs.vartype;
      end;


    function tsubscriptnode.pass_1 : tnode;
      begin
         result:=nil;
         firstpass(left);
         if codegenerror then
          exit;

         registers32:=left.registers32;
         registersfpu:=left.registersfpu;
{$ifdef SUPPORT_MMX}
         registersmmx:=left.registersmmx;
{$endif SUPPORT_MMX}
         { classes must be dereferenced implicit }
         if is_class_or_interface(left.resulttype.def) then
           begin
              if registers32=0 then
                registers32:=1;
              location.loc:=LOC_REFERENCE;
           end
         else
           begin
              if (left.location.loc<>LOC_CREFERENCE) and
                 (left.location.loc<>LOC_REFERENCE) then
                CGMessage(cg_e_illegal_expression);
              location.loc:=left.location.loc;
           end;
      end;

    function tsubscriptnode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p) and
          (vs = tsubscriptnode(p).vs);
      end;


{*****************************************************************************
                               TVECNODE
*****************************************************************************}

    constructor tvecnode.create(l,r : tnode);

      begin
         inherited create(vecn,l,r);
      end;


    function tvecnode.det_resulttype:tnode;
      var
         htype : ttype;
         ct : tconverttype;
      begin
         result:=nil;
         resulttypepass(left);
         resulttypepass(right);
         if codegenerror then
          exit;

         { range check only for arrays }
         if (left.resulttype.def.deftype=arraydef) then
           begin
              if (isconvertable(right.resulttype.def,tarraydef(left.resulttype.def).rangetype.def,
                    ct,ordconstn,false)=0) and
                 not(is_equal(right.resulttype.def,tarraydef(left.resulttype.def).rangetype.def)) then
                CGMessage(type_e_mismatch);
           end;
         { Never convert a boolean or a char !}
         { maybe type conversion }
         if (right.resulttype.def.deftype<>enumdef) and
            not(is_char(right.resulttype.def)) and
            not(is_boolean(right.resulttype.def)) then
           begin
             inserttypeconv(right,s32bittype);
           end;

         { are we accessing a pointer[], then convert the pointer to
           an array first, in FPC this is allowed for all pointers in
           delphi/tp7 it's only allowed for pchars }
         if (left.resulttype.def.deftype=pointerdef) and
            ((m_fpc in aktmodeswitches) or
             is_pchar(left.resulttype.def) or
             is_pwidechar(left.resulttype.def)) then
          begin
            { convert pointer to array }
            htype.setdef(tarraydef.create(0,$7fffffff,s32bittype));
            tarraydef(htype.def).elementtype:=tpointerdef(left.resulttype.def).pointertype;
            inserttypeconv(left,htype);

            resulttype:=tarraydef(htype.def).elementtype;
          end;

         { determine return type }
         if not assigned(resulttype.def) then
           if left.resulttype.def.deftype=arraydef then
             resulttype:=tarraydef(left.resulttype.def).elementtype
           else if left.resulttype.def.deftype=stringdef then
             begin
                { indexed access to strings }
                case tstringdef(left.resulttype.def).string_typ of
                   st_widestring :
                     resulttype:=cwidechartype;
                   st_ansistring :
                     resulttype:=cchartype;
                   st_longstring :
                     resulttype:=cchartype;
                   st_shortstring :
                     resulttype:=cchartype;
                end;
             end
           else
             CGMessage(type_e_array_required);
      end;


    function tvecnode.pass_1 : tnode;
{$ifdef consteval}
      var
         tcsym : ttypedconstsym;
{$endif}
      begin
         result:=nil;
         firstpass(left);
         firstpass(right);
         if codegenerror then
           exit;

         { the register calculation is easy if a const index is used }
         if right.nodetype=ordconstn then
           begin
{$ifdef consteval}
              { constant evaluation }
              if (left.nodetype=loadn) and
                 (left.symtableentry.typ=typedconstsym) then
               begin
                 tcsym:=ttypedconstsym(left.symtableentry);
                 if tcsym.defintion^.typ=stringdef then
                  begin

                  end;
               end;
{$endif}
              registers32:=left.registers32;

              { for ansi/wide strings, we need at least one register }
              if is_ansistring(left.resulttype.def) or
                is_widestring(left.resulttype.def) or
              { ... as well as for dynamic arrays }
                is_dynamic_array(left.resulttype.def) then
                registers32:=max(registers32,1);
           end
         else
           begin
              { this rules are suboptimal, but they should give }
              { good results                                }
              registers32:=max(left.registers32,right.registers32);

              { for ansi/wide strings, we need at least one register }
              if is_ansistring(left.resulttype.def) or
                is_widestring(left.resulttype.def) or
              { ... as well as for dynamic arrays }
                is_dynamic_array(left.resulttype.def) then
                registers32:=max(registers32,1);

              { need we an extra register when doing the restore ? }
              if (left.registers32<=right.registers32) and
              { only if the node needs less than 3 registers }
              { two for the right node and one for the       }
              { left address                             }
                (registers32<3) then
                inc(registers32);

              { need we an extra register for the index ? }
              if (right.location.loc<>LOC_REGISTER)
              { only if the right node doesn't need a register }
                and (right.registers32<1) then
                inc(registers32);

              { not correct, but what works better ?
              if left.registers32>0 then
                registers32:=max(registers32,2)
              else
                 min. one register
                registers32:=max(registers32,1);
              }
           end;
         registersfpu:=max(left.registersfpu,right.registersfpu);
{$ifdef SUPPORT_MMX}
         registersmmx:=max(left.registersmmx,right.registersmmx);
{$endif SUPPORT_MMX}
         if left.location.loc in [LOC_CREGISTER,LOC_REFERENCE] then
           location.loc:=LOC_REFERENCE
         else
           location.loc:=LOC_CREFERENCE;
      end;


{*****************************************************************************
                               TSELFNODE
*****************************************************************************}

    constructor tselfnode.create(_class : tdef);

      begin
         inherited create(selfn);
         classdef:=_class;
      end;

    function tselfnode.det_resulttype:tnode;
      begin
        result:=nil;
        resulttype.setdef(classdef);
      end;

    function tselfnode.pass_1 : tnode;
      begin
         result:=nil;
         if (resulttype.def.deftype=classrefdef) or
           is_class(resulttype.def) then
           location.loc:=LOC_CREGISTER
         else
           location.loc:=LOC_REFERENCE;
      end;


{*****************************************************************************
                               TWITHNODE
*****************************************************************************}

    constructor twithnode.create(symtable : twithsymtable;l,r : tnode;count : longint);

      begin
         inherited create(withn,l,r);
         withsymtable:=symtable;
         tablecount:=count;
         FillChar(withreference,sizeof(withreference),0);
         set_file_line(l);
      end;


    destructor twithnode.destroy;
      var
        hsymt,
        symt : tsymtable;
        i    : longint;
      begin
        symt:=withsymtable;
        for i:=1 to tablecount do
         begin
           if assigned(symt) then
            begin
              hsymt:=symt.next;
              symt.free;
              symt:=hsymt;
            end;
         end;
        inherited destroy;
      end;


    function twithnode.getcopy : tnode;

      var
         p : twithnode;

      begin
         p:=twithnode(inherited getcopy);
         p.withsymtable:=withsymtable;
         p.tablecount:=tablecount;
         p.withreference:=withreference;
         result:=p;
      end;

    function twithnode.det_resulttype:tnode;
      var
         symtable : tsymtable;
         i : longint;
      begin
         result:=nil;
         resulttype:=voidtype;
         if assigned(left) and assigned(right) then
          begin
            resulttypepass(left);
            unset_varstate(left);
            set_varstate(left,true);
            if codegenerror then
             exit;

            symtable:=withsymtable;
            for i:=1 to tablecount do
             begin
               if (left.nodetype=loadn) and
                  (tloadnode(left).symtable=aktprocdef.localst) then
                twithsymtable(symtable).direct_with:=true;
               twithsymtable(symtable).withnode:=self;
               symtable:=symtable.next;
             end;

            resulttypepass(right);
            if codegenerror then
             exit;
          end;
        resulttype:=voidtype;
      end;


    function twithnode.pass_1 : tnode;
      begin
         result:=nil;
         if assigned(left) and assigned(right) then
            begin
               firstpass(left);
               firstpass(right);
               if codegenerror then
                 exit;

               left_right_max;
            end
         else
           begin
              { optimization }
              result:=nil;
           end;
      end;

    function twithnode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p) and
          (withsymtable = twithnode(p).withsymtable) and
          (tablecount = twithnode(p).tablecount);
      end;

begin
  cloadvmtnode := tloadvmtnode;
  chnewnode := thnewnode;
  chdisposenode := thdisposenode;
  caddrnode := taddrnode;
  cdoubleaddrnode := tdoubleaddrnode;
  cderefnode := tderefnode;
  csubscriptnode := tsubscriptnode;
  cvecnode := tvecnode;
  cselfnode := tselfnode;
  cwithnode := twithnode;
end.
{
  $Log$
  Revision 1.34  2002-07-20 11:57:54  florian
    * types.pas renamed to defbase.pas because D6 contains a types
      unit so this would conflicts if D6 programms are compiled
    + Willamette/SSE2 instructions to assembler added

  Revision 1.33  2002/05/18 13:34:10  peter
    * readded missing revisions

  Revision 1.32  2002/05/16 19:46:39  carl
  + defines.inc -> fpcdefs.inc to avoid conflicts if compiling by hand
  + try to fix temp allocation (still in ifdef)
  + generic constructor calls
  + start of tassembler / tmodulebase class cleanup

  Revision 1.30  2002/05/12 16:53:07  peter
    * moved entry and exitcode to ncgutil and cgobj
    * foreach gets extra argument for passing local data to the
      iterator function
    * -CR checks also class typecasts at runtime by changing them
      into as
    * fixed compiler to cycle with the -CR option
    * fixed stabs with elf writer, finally the global variables can
      be watched
    * removed a lot of routines from cga unit and replaced them by
      calls to cgobj
    * u32bit-s32bit updates for and,or,xor nodes. When one element is
      u32bit then the other is typecasted also to u32bit without giving
      a rangecheck warning/error.
    * fixed pascal calling method with reversing also the high tree in
      the parast, detected by tcalcst3 test

  Revision 1.29  2002/04/21 19:02:04  peter
    * removed newn and disposen nodes, the code is now directly
      inlined from pexpr
    * -an option that will write the secondpass nodes to the .s file, this
      requires EXTDEBUG define to actually write the info
    * fixed various internal errors and crashes due recent code changes

  Revision 1.28  2002/04/20 21:32:23  carl
  + generic FPC_CHECKPOINTER
  + first parameter offset in stack now portable
  * rename some constants
  + move some cpu stuff to other units
  - remove unused constents
  * fix stacksize for some targets
  * fix generic size problems which depend now on EXTEND_SIZE constant

  Revision 1.27  2002/04/02 17:11:29  peter
    * tlocation,treference update
    * LOC_CONSTANT added for better constant handling
    * secondadd splitted in multiple routines
    * location_force_reg added for loading a location to a register
      of a specified size
    * secondassignment parses now first the right and then the left node
      (this is compatible with Kylix). This saves a lot of push/pop especially
      with string operations
    * adapted some routines to use the new cg methods

  Revision 1.26  2002/04/01 20:57:13  jonas
    * fixed web bug 1907
    * fixed some other procvar related bugs (all related to accepting procvar
        constructs with either too many or too little parameters)
    (both merged, includes second typo fix of pexpr.pas)

}