freepascal.compiler/compiler/nld.pas

{
    Copyright (c) 2000-2002 by Florian Klaempfl

    Type checking and register allocation for load/assignment 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 nld;

{$i fpcdefs.inc}

interface

    uses
       node,
       {$ifdef state_tracking}
       nstate,
       {$endif}
       symconst,symbase,symtype,symsym,symdef;

    type
       Trttidatatype=(rdt_normal,rdt_ord2str,rdt_str2ord);

       tloadnode = class(tunarynode)
       protected
          procdef : tprocdef;
          procdefderef : tderef;
       public
          symtableentry : tsym;
          symtableentryderef : tderef;
          symtable : TSymtable;
          constructor create(v : tsym;st : TSymtable);virtual;
          constructor create_procvar(v : tsym;d:tprocdef;st : TSymtable);virtual;
          constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
          procedure ppuwrite(ppufile:tcompilerppufile);override;
          procedure buildderefimpl;override;
          procedure derefimpl;override;
          procedure set_mp(p:tnode);
          function  is_addr_param_load:boolean;
          function  dogetcopy : tnode;override;
          function  pass_1 : tnode;override;
          function  pass_typecheck:tnode;override;
          procedure mark_write;override;
          function  docompare(p: tnode): boolean; override;
          procedure printnodedata(var t:text);override;
          procedure setprocdef(p : tprocdef);
       end;
       tloadnodeclass = class of tloadnode;

       { different assignment types }
       tassigntype = (at_normal,at_plus,at_minus,at_star,at_slash);

       tassignmentnode = class(tbinarynode)
          assigntype : tassigntype;
          constructor create(l,r : tnode);virtual;
          constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
          procedure ppuwrite(ppufile:tcompilerppufile);override;
          function dogetcopy : tnode;override;
          function pass_1 : tnode;override;
          function pass_typecheck:tnode;override;
       {$ifdef state_tracking}
          function track_state_pass(exec_known:boolean):boolean;override;
       {$endif state_tracking}
          function docompare(p: tnode): boolean; override;
       end;
       tassignmentnodeclass = class of tassignmentnode;

       tarrayconstructorrangenode = class(tbinarynode)
          constructor create(l,r : tnode);virtual;
          function pass_1 : tnode;override;
          function pass_typecheck:tnode;override;
       end;
       tarrayconstructorrangenodeclass = class of tarrayconstructorrangenode;

       tarrayconstructornode = class(tbinarynode)
          constructor create(l,r : tnode);virtual;
          function dogetcopy : tnode;override;
          function pass_1 : tnode;override;
          function pass_typecheck:tnode;override;
          function docompare(p: tnode): boolean; override;
          procedure force_type(def:tdef);
          procedure insert_typeconvs;
       end;
       tarrayconstructornodeclass = class of tarrayconstructornode;

       ttypenode = class(tnode)
          allowed : boolean;
          typedef : tdef;
          typedefderef : tderef;
          constructor create(def:tdef);virtual;
          constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
          procedure ppuwrite(ppufile:tcompilerppufile);override;
          procedure buildderefimpl;override;
          procedure derefimpl;override;
          function pass_1 : tnode;override;
          function pass_typecheck:tnode;override;
          function  dogetcopy : tnode;override;
          function docompare(p: tnode): boolean; override;
       end;
       ttypenodeclass = class of ttypenode;

       trttinode = class(tnode)
          l1,l2  : longint;
          rttitype : trttitype;
          rttidef : tstoreddef;
          rttidefderef : tderef;
          rttidatatype : Trttidatatype;
          constructor create(def:tstoreddef;rt:trttitype;dt:Trttidatatype);virtual;
          constructor ppuload(t:tnodetype;ppufile:tcompilerppufile);override;
          procedure ppuwrite(ppufile:tcompilerppufile);override;
          procedure buildderefimpl;override;
          procedure derefimpl;override;
          function  dogetcopy : tnode;override;
          function pass_1 : tnode;override;
          function pass_typecheck:tnode;override;
          function docompare(p: tnode): boolean; override;
       end;
       trttinodeclass = class of trttinode;

    var
       cloadnode : tloadnodeclass;
       cassignmentnode : tassignmentnodeclass;
       carrayconstructorrangenode : tarrayconstructorrangenodeclass;
       carrayconstructornode : tarrayconstructornodeclass;
       ctypenode : ttypenodeclass;
       crttinode : trttinodeclass;

       { Current assignment node }
       aktassignmentnode : tassignmentnode;


implementation

    uses
      cutils,verbose,globtype,globals,systems,
      symnot,
      defutil,defcmp,
      htypechk,pass_1,procinfo,paramgr,
      ncon,ninl,ncnv,nmem,ncal,nutils,nbas,
      cgobj,cgbase
      ;

{*****************************************************************************
                             TLOADNODE
*****************************************************************************}

    constructor tloadnode.create(v : tsym;st : TSymtable);
      begin
         inherited create(loadn,nil);
         if not assigned(v) then
          internalerror(200108121);
         symtableentry:=v;
         symtable:=st;
         procdef:=nil;
      end;


    constructor tloadnode.create_procvar(v : tsym;d:tprocdef;st : TSymtable);
      begin
         inherited create(loadn,nil);
         if not assigned(v) then
          internalerror(200108121);
         symtableentry:=v;
         symtable:=st;
         procdef:=d;
      end;


    constructor tloadnode.ppuload(t:tnodetype;ppufile:tcompilerppufile);
      begin
        inherited ppuload(t,ppufile);
        ppufile.getderef(symtableentryderef);
        symtable:=nil;
        ppufile.getderef(procdefderef);
      end;


    procedure tloadnode.ppuwrite(ppufile:tcompilerppufile);
      begin
        inherited ppuwrite(ppufile);
        ppufile.putderef(symtableentryderef);
        ppufile.putderef(procdefderef);
      end;


    procedure tloadnode.buildderefimpl;
      begin
        inherited buildderefimpl;
        symtableentryderef.build(symtableentry);
        procdefderef.build(procdef);
      end;


    procedure tloadnode.derefimpl;
      begin
        inherited derefimpl;
        symtableentry:=tsym(symtableentryderef.resolve);
        symtable:=symtableentry.owner;
        procdef:=tprocdef(procdefderef.resolve);
      end;


    procedure tloadnode.set_mp(p:tnode);
      begin
        { typen nodes should not be set }
        if p.nodetype=typen then
          internalerror(200301042);
        left:=p;
      end;


    function tloadnode.dogetcopy : tnode;
      var
         n : tloadnode;

      begin
         n:=tloadnode(inherited dogetcopy);
         n.symtable:=symtable;
         n.symtableentry:=symtableentry;
         n.procdef:=procdef;
         result:=n;
      end;


    function tloadnode.is_addr_param_load:boolean;
      begin
        result:=(symtable.symtabletype=parasymtable) and
                (symtableentry.typ=paravarsym) and
                not(vo_has_local_copy in tparavarsym(symtableentry).varoptions) and
                not(nf_load_self_pointer in flags) and
                paramanager.push_addr_param(tparavarsym(symtableentry).varspez,tparavarsym(symtableentry).vardef,tprocdef(symtable.defowner).proccalloption);
      end;


    function tloadnode.pass_typecheck:tnode;
      begin
         result:=nil;
         case symtableentry.typ of
           absolutevarsym :
             resultdef:=tabsolutevarsym(symtableentry).vardef;
           constsym:
             begin
               if tconstsym(symtableentry).consttyp=constresourcestring then
                 resultdef:=cansistringtype
               else
                 internalerror(22799);
             end;
           staticvarsym :
             begin
               tabstractvarsym(symtableentry).IncRefCountBy(1);
               { static variables referenced in procedures or from finalization,
                 variable needs to be in memory.
                 It is too hard and the benefit is too small to detect whether a
                 variable is only used in the finalization to add support for it (PFV) }
               if assigned(current_procinfo) and
                  (symtable.symtabletype=staticsymtable) and
                  (
                    (symtable.symtablelevel<>current_procinfo.procdef.localst.symtablelevel) or
                    (current_procinfo.procdef.proctypeoption=potype_unitfinalize)
                  ) then
                 make_not_regable(self,[ra_addr_taken]);
               resultdef:=tabstractvarsym(symtableentry).vardef;
             end;
           paravarsym,
           localvarsym :
             begin
               tabstractvarsym(symtableentry).IncRefCountBy(1);
               { Nested variable? The we need to load the framepointer of
                 the parent procedure }
               if assigned(current_procinfo) and
                  (symtable.symtabletype in [localsymtable,parasymtable]) and
                  (symtable.symtablelevel<>current_procinfo.procdef.parast.symtablelevel) then
                 begin
                   if assigned(left) then
                     internalerror(200309289);
                   left:=cloadparentfpnode.create(tprocdef(symtable.defowner));
                   { we can't inline the referenced parent procedure }
                   exclude(tprocdef(symtable.defowner).procoptions,po_inline);
                   { reference in nested procedures, variable needs to be in memory }
                   { and behaves as if its address escapes its parent block         }
                   make_not_regable(self,[ra_addr_taken]);
                 end;
               { fix self type which is declared as voidpointer in the
                 definition }
               if vo_is_self in tabstractvarsym(symtableentry).varoptions then
                 begin
                   resultdef:=tprocdef(symtableentry.owner.defowner)._class;
                   if (po_classmethod in tprocdef(symtableentry.owner.defowner).procoptions) or
                      (po_staticmethod in tprocdef(symtableentry.owner.defowner).procoptions) then
                     resultdef:=tclassrefdef.create(resultdef)
                   else if is_object(resultdef) and
                           (nf_load_self_pointer in flags) then
                     resultdef:=tpointerdef.create(resultdef);
                 end
               else if vo_is_vmt in tabstractvarsym(symtableentry).varoptions then
                 begin
                   resultdef:=tprocdef(symtableentry.owner.defowner)._class;
                   resultdef:=tclassrefdef.create(resultdef);
                 end
               else
                 resultdef:=tabstractvarsym(symtableentry).vardef;
             end;
           procsym :
             begin
               { Return the first procdef. In case of overlaoded
                 procdefs the matching procdef will be choosen
                 when the expected procvardef is known, see get_information
                 in htypechk.pas (PFV) }
               if not assigned(procdef) then
                 procdef:=tprocdef(tprocsym(symtableentry).ProcdefList[0])
               else if po_kylixlocal in procdef.procoptions then
                 CGMessage(type_e_cant_take_address_of_local_subroutine);

               { the result is a procdef, addrn and proc_to_procvar
                 typeconvn need this as resultdef so they know
                 that the address needs to be returned }
               resultdef:=procdef;

               { process methodpointer }
               if assigned(left) then
                 typecheckpass(left);
             end;
           labelsym:
             resultdef:=voidtype;
           else
             internalerror(200104141);
         end;
      end;

    procedure Tloadnode.mark_write;

    begin
      include(flags,nf_write);
    end;

    function tloadnode.pass_1 : tnode;
      begin
         result:=nil;
         expectloc:=LOC_REFERENCE;
         registersint:=0;
         registersfpu:=0;
{$ifdef SUPPORT_MMX}
         registersmmx:=0;
{$endif SUPPORT_MMX}
         if (cs_create_pic in current_settings.moduleswitches) and
           not(symtableentry.typ in [paravarsym,localvarsym]) then
           include(current_procinfo.flags,pi_needs_got);

         case symtableentry.typ of
            absolutevarsym :
              ;
            constsym:
              begin
                 if tconstsym(symtableentry).consttyp=constresourcestring then
                   expectloc:=LOC_CREFERENCE;
              end;
            staticvarsym,
            localvarsym,
            paravarsym :
              begin
                if assigned(left) then
                  firstpass(left);
                if not is_addr_param_load and
                   tabstractvarsym(symtableentry).is_regvar(is_addr_param_load) then
                  expectloc:=tvarregable2tcgloc[tabstractvarsym(symtableentry).varregable]
                else
                  if (tabstractvarsym(symtableentry).varspez=vs_const) then
                    expectloc:=LOC_CREFERENCE;
                { we need a register for call by reference parameters }
                if paramanager.push_addr_param(tabstractvarsym(symtableentry).varspez,tabstractvarsym(symtableentry).vardef,pocall_default) then
                  registersint:=1;
                if ([vo_is_thread_var,vo_is_dll_var]*tabstractvarsym(symtableentry).varoptions)<>[] then
                  registersint:=1;
                if (target_info.system=system_powerpc_darwin) and
                   ([vo_is_dll_var,vo_is_external] * tabstractvarsym(symtableentry).varoptions <> []) then
                  include(current_procinfo.flags,pi_needs_got);
                { call to get address of threadvar }
                if (vo_is_thread_var in tabstractvarsym(symtableentry).varoptions) then
                  include(current_procinfo.flags,pi_do_call);
                if nf_write in flags then
                  Tabstractvarsym(symtableentry).trigger_notifications(vn_onwrite)
                else
                  Tabstractvarsym(symtableentry).trigger_notifications(vn_onread);
                { count variable references }
                if cg.t_times>1 then
                  tabstractvarsym(symtableentry).IncRefCountBy(cg.t_times-1);
              end;
            procsym :
                begin
                   { method pointer ? }
                   if assigned(left) then
                     begin
                        expectloc:=LOC_CREFERENCE;
                        firstpass(left);
                        registersint:=max(registersint,left.registersint);
                        registersfpu:=max(registersfpu,left.registersfpu);
 {$ifdef SUPPORT_MMX}
                        registersmmx:=max(registersmmx,left.registersmmx);
 {$endif SUPPORT_MMX}
                     end;
                end;
           labelsym :
             ;
           else
             internalerror(200104143);
         end;
      end;


    function tloadnode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p) and
          (symtableentry = tloadnode(p).symtableentry) and
          (procdef = tloadnode(p).procdef) and
          (symtable = tloadnode(p).symtable);
      end;


    procedure tloadnode.printnodedata(var t:text);
      begin
        inherited printnodedata(t);
        write(t,printnodeindention,'symbol = ',symtableentry.name);
        if symtableentry.typ=procsym then
          write(t,printnodeindention,'procdef = ',procdef.mangledname);
        writeln(t,'');
      end;


    procedure tloadnode.setprocdef(p : tprocdef);
      begin
        procdef:=p;
        resultdef:=p;
        if po_local in p.procoptions then
          CGMessage(type_e_cant_take_address_of_local_subroutine);
      end;

{*****************************************************************************
                             TASSIGNMENTNODE
*****************************************************************************}

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

      begin
         inherited create(assignn,l,r);
         l.mark_write;
         assigntype:=at_normal;
      end;


    constructor tassignmentnode.ppuload(t:tnodetype;ppufile:tcompilerppufile);
      begin
        inherited ppuload(t,ppufile);
        assigntype:=tassigntype(ppufile.getbyte);
      end;


    procedure tassignmentnode.ppuwrite(ppufile:tcompilerppufile);
      begin
        inherited ppuwrite(ppufile);
        ppufile.putbyte(byte(assigntype));
      end;


    function tassignmentnode.dogetcopy : tnode;

      var
         n : tassignmentnode;

      begin
         n:=tassignmentnode(inherited dogetcopy);
         n.assigntype:=assigntype;
         result:=n;
      end;


    function tassignmentnode.pass_typecheck:tnode;
      var
        hp : tnode;
        useshelper : boolean;
      begin
        result:=nil;
        resultdef:=voidtype;

        { must be made unique }
        set_unique(left);

        typecheckpass(left);
        typecheckpass(right);
        set_varstate(right,vs_read,[vsf_must_be_valid]);
        set_varstate(left,vs_written,[]);
        if codegenerror then
          exit;

        { tp procvar support, when we don't expect a procvar
          then we need to call the procvar }
        if (left.resultdef.typ<>procvardef) then
          maybe_call_procvar(right,true);

        { assignments to formaldefs and open arrays aren't allowed }
        if (left.resultdef.typ=formaldef) or
           is_open_array(left.resultdef) then
          CGMessage(type_e_assignment_not_allowed);

        { test if node can be assigned, properties are allowed }
        valid_for_assignment(left,true);

        { assigning nil to a dynamic array clears the array }
        if is_dynamic_array(left.resultdef) and
           (right.nodetype=niln) then
         begin
           { remove property flag to avoid errors, see comments for }
           { tf_winlikewidestring assignments below                 }
           exclude(left.flags,nf_isproperty);
           hp:=ccallparanode.create(caddrnode.create_internal
                   (crttinode.create(tstoreddef(left.resultdef),initrtti,rdt_normal)),
               ccallparanode.create(ctypeconvnode.create_internal(left,voidpointertype),nil));
           result := ccallnode.createintern('fpc_dynarray_clear',hp);
           left:=nil;
           exit;
         end;

        { shortstring helpers can do the conversion directly,
          so treat them separatly }
        if (is_shortstring(left.resultdef)) then
         begin
           { insert typeconv, except for chars that are handled in
             secondpass and except for ansi/wide string that can
             be converted immediatly }
           if not(is_char(right.resultdef) or
                  (right.resultdef.typ=stringdef)) then
             inserttypeconv(right,left.resultdef);
           if right.resultdef.typ=stringdef then
            begin
              useshelper:=true;
              { convert constant strings to shortstrings. But
                skip empty constant strings, that will be handled
                in secondpass }
              if (right.nodetype=stringconstn) then
                begin
                  { verify if range fits within shortstring }
                  { just emit a warning, delphi gives an    }
                  { error, only if the type definition of   }
                  { of the string is less  < 255 characters }
                  if not is_open_string(left.resultdef) and
                     (tstringconstnode(right).len > tstringdef(left.resultdef).len) then
                     cgmessage(type_w_string_too_long);
                  inserttypeconv(right,left.resultdef);
                  if (right.nodetype=stringconstn) and
                     (tstringconstnode(right).len=0) then
                    useshelper:=false;
                end;
             { rest is done in pass 1 (JM) }
             if useshelper then
               exit;
            end
         end
        else
          begin
            { check if the assignment may cause a range check error }
            check_ranges(fileinfo,right,left.resultdef);
            inserttypeconv(right,left.resultdef);
          end;

        { call helpers for interface }
        if is_interfacecom(left.resultdef) then
         begin
	   { Normal interface assignments are handled by the generic refcount incr/decr }
           if not right.resultdef.is_related(left.resultdef) then
             begin
               { remove property flag to avoid errors, see comments for }
               { tf_winlikewidestring assignments below                 }
               exclude(left.flags,nf_isproperty);
               hp:=
                 ccallparanode.create(
                   cguidconstnode.create(tobjectdef(left.resultdef).iidguid^),
                 ccallparanode.create(
                   ctypeconvnode.create_internal(right,voidpointertype),
                 ccallparanode.create(
                   ctypeconvnode.create_internal(left,voidpointertype),
                   nil)));
               result:=ccallnode.createintern('fpc_intf_assign_by_iid',hp);
               left:=nil;
               right:=nil;
               exit;
             end;
         end
        { call helpers for variant, they can contain non ref. counted types like
          vararrays which must be really copied }
        else if left.resultdef.typ=variantdef then
         begin
           hp:=ccallparanode.create(ctypeconvnode.create_internal(
                 caddrnode.create_internal(right),voidpointertype),
               ccallparanode.create(ctypeconvnode.create_internal(
                 caddrnode.create_internal(left),voidpointertype),
               nil));
           result:=ccallnode.createintern('fpc_variant_copy',hp);
           left:=nil;
           right:=nil;
           exit;
         end
        { call helpers for composite types containing automated types }
        else if (left.resultdef.needs_inittable) and
            (left.resultdef.typ in [arraydef,objectdef,recorddef]) then
         begin
           hp:=ccallparanode.create(caddrnode.create_internal(
                  crttinode.create(tstoreddef(left.resultdef),initrtti,rdt_normal)),
               ccallparanode.create(ctypeconvnode.create_internal(
                 caddrnode.create_internal(left),voidpointertype),
               ccallparanode.create(ctypeconvnode.create_internal(
                 caddrnode.create_internal(right),voidpointertype),
               nil)));
           result:=ccallnode.createintern('fpc_copy',hp);
           left:=nil;
           right:=nil;
           exit;
         end
        { call helpers for windows widestrings, they aren't ref. counted }
        else if (tf_winlikewidestring in target_info.flags) and is_widestring(left.resultdef) then
         begin
           { The first argument of fpc_widestr_assign is a var parameter. Properties cannot   }
           { be passed to var or out parameters, because in that case setters/getters are not }
           { used. Further, if we would allow it in case there are no getters or setters, you }
           { would need source changes in case these are introduced later on, thus defeating  }
           { part of the transparency advantages of properties. In this particular case,      }
           { however:                                                                         }
           {   a) if there is a setter, this code will not be used since then the assignment  }
           {      will be converted to a procedure call                                       }
           {   b) the getter is irrelevant, because fpc_widestr_assign must always decrease   }
           {      the refcount of the field to which we are writing                           }
           {   c) source code changes are not required if a setter is added/removed, because  }
           {      this transformation is handled at compile time                              }
           {  -> we can remove the nf_isproperty flag (if any) from left, so that in case it  }
           {     is a property which refers to a field without a setter call, we will not get }
           {     an error about trying to pass a property as a var parameter                  }
           exclude(left.flags,nf_isproperty);
           hp:=ccallparanode.create(ctypeconvnode.create_internal(right,voidpointertype),
               ccallparanode.create(ctypeconvnode.create_internal(left,voidpointertype),
               nil));
           result:=ccallnode.createintern('fpc_widestr_assign',hp);
           left:=nil;
           right:=nil;
           exit;
         end;

        { check if local proc/func is assigned to procvar }
        if right.resultdef.typ=procvardef then
          test_local_to_procvar(tprocvardef(right.resultdef),left.resultdef);
      end;


    function tassignmentnode.pass_1 : tnode;
      var
        hp: tnode;
        oldassignmentnode : tassignmentnode;
      begin
         result:=nil;
         expectloc:=LOC_VOID;

         firstpass(left);

         { Optimize the reuse of the destination of the assingment in left.
           Allow the use of the left inside the tree generated on the right.
           This is especially usefull for string routines where the destination
           is pushed as a parameter. Using the final destination of left directly
           save a temp allocation and copy of data (PFV) }
         oldassignmentnode:=aktassignmentnode;
         if right.nodetype=addn then
           aktassignmentnode:=self
         else
           aktassignmentnode:=nil;
         firstpass(right);
         aktassignmentnode:=oldassignmentnode;
         if nf_assign_done_in_right in flags then
           begin
             result:=right;
             right:=nil;
             exit;
           end;

         if codegenerror then
           exit;

         { if right is a function call for which the address of the result  }
         { is allocated by the caller and passed to the function via an     }
         { invisible function result, try to pass the x in "x:=f(...)" as   }
         { that function result instead. Condition: x cannot be accessible  }
         { from within f. This is the case if x is a temp, or x is a local  }
         { variable or value parameter of the current block and its address }
         { is not passed to f. One problem: what if someone takes the       }
         { address of x, puts it in a pointer variable/field and then       }
         { accesses it that way from within the function? This is solved    }
         { (in a conservative way) using the ti_addr_taken/addr_taken flags }
         if (cs_opt_level1 in current_settings.optimizerswitches) and
            (right.nodetype = calln) and
            (right.resultdef=left.resultdef) and
            { left must be a temp, since otherwise as soon as you modify the }
            { result, the current left node is modified and that one may     }
            { still be an argument to the function or even accessed in the   }
            { function                                                       }
            (
             (
              (((left.nodetype = temprefn) and
                not(ti_addr_taken in ttemprefnode(left).tempinfo^.flags) and
                not(ti_may_be_in_reg in ttemprefnode(left).tempinfo^.flags)) or
               ((left.nodetype = loadn) and
                { nested procedures may access the current procedure's locals }
                (tcallnode(right).procdefinition.parast.symtablelevel=normal_function_level) and
                { must be a local variable or a value para }
                ((tloadnode(left).symtableentry.typ = localvarsym) or
                 ((tloadnode(left).symtableentry.typ = paravarsym) and
                  (tparavarsym(tloadnode(left).symtableentry).varspez = vs_value)
                 )
                ) and
                { the address may not have been taken of the variable/parameter, because }
                { otherwise it's possible that the called function can access it via a   }
                { global variable or other stored state                                  }
                not(tabstractvarsym(tloadnode(left).symtableentry).addr_taken) and
                (tabstractvarsym(tloadnode(left).symtableentry).varregable in [vr_none,vr_addr])
               )
              ) and
              paramanager.ret_in_param(right.resultdef,tcallnode(right).procdefinition.proccalloption)
             ) or
             { there's special support for ansi/widestrings in the callnode }
             is_ansistring(right.resultdef) or
             is_widestring(right.resultdef)
            )  then
           begin
             if assigned(tcallnode(right).funcretnode) then
               internalerror(2007080201);
             tcallnode(right).funcretnode := left;
             result := right;
             left := nil;
             right := nil;
             exit;
           end;

         { assignment to refcounted variable -> inc/decref }
         if (not is_class(left.resultdef) and
            left.resultdef.needs_inittable) then
           include(current_procinfo.flags,pi_do_call);


        if (is_shortstring(left.resultdef)) then
          begin
           if right.resultdef.typ=stringdef then
            begin
              if (right.nodetype<>stringconstn) or
                 (tstringconstnode(right).len<>0) then
               begin
                 hp:=ccallparanode.create
                       (right,
                  ccallparanode.create(cinlinenode.create
                       (in_high_x,false,left.getcopy),nil));
                 result:=ccallnode.createinternreturn('fpc_'+tstringdef(right.resultdef).stringtypname+'_to_shortstr',hp,left);
                 firstpass(result);
                 left:=nil;
                 right:=nil;
                 exit;
               end;
            end;
           end;

         registersint:=left.registersint+right.registersint;
         registersfpu:=max(left.registersfpu,right.registersfpu);
{$ifdef SUPPORT_MMX}
         registersmmx:=max(left.registersmmx,right.registersmmx);
{$endif SUPPORT_MMX}
      end;


    function tassignmentnode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p) and
          (assigntype = tassignmentnode(p).assigntype);
      end;

{$ifdef state_tracking}
    function Tassignmentnode.track_state_pass(exec_known:boolean):boolean;

    var se:Tstate_entry;

    begin
        track_state_pass:=false;
        if exec_known then
            begin
                track_state_pass:=right.track_state_pass(exec_known);
                {Force a new resultdef pass.}
                right.resultdef:=nil;
                do_typecheckpass(right);
                typecheckpass(right);
                aktstate.store_fact(left.getcopy,right.getcopy);
            end
        else
            aktstate.delete_fact(left);
    end;
{$endif}


{*****************************************************************************
                           TARRAYCONSTRUCTORRANGENODE
*****************************************************************************}

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

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

    function tarrayconstructorrangenode.pass_typecheck:tnode;
      begin
        result:=nil;
        typecheckpass(left);
        typecheckpass(right);
        set_varstate(left,vs_read,[vsf_must_be_valid]);
        set_varstate(right,vs_read,[vsf_must_be_valid]);
        if codegenerror then
         exit;
        resultdef:=left.resultdef;
      end;


    function tarrayconstructorrangenode.pass_1 : tnode;
      begin
        firstpass(left);
        firstpass(right);
        expectloc:=LOC_CREFERENCE;
        calcregisters(self,0,0,0);
        result:=nil;
      end;


{****************************************************************************
                            TARRAYCONSTRUCTORNODE
*****************************************************************************}

    constructor tarrayconstructornode.create(l,r : tnode);
      begin
         inherited create(arrayconstructorn,l,r);
      end;


    function tarrayconstructornode.dogetcopy : tnode;
      var
         n : tarrayconstructornode;
      begin
         n:=tarrayconstructornode(inherited dogetcopy);
         result:=n;
      end;


    function tarrayconstructornode.pass_typecheck:tnode;
      var
        hdef  : tdef;
        hp    : tarrayconstructornode;
        len   : longint;
        varia : boolean;
        eq    : tequaltype;
        hnodetype : tnodetype;
      begin
        result:=nil;

      { are we allowing array constructor? Then convert it to a set.
        Do this only if we didn't convert the arrayconstructor yet. This
        is needed for the cases where the resultdef is forced for a second
        run }
        if (not allow_array_constructor) then
         begin
           hp:=tarrayconstructornode(getcopy);
           arrayconstructor_to_set(tnode(hp));
           result:=hp;
           exit;
         end;

      { only pass left tree, right tree contains next construct if any }
        hdef:=nil;
        hnodetype:=errorn;
        len:=0;
        varia:=false;
        if assigned(left) then
         begin
           hp:=self;
           while assigned(hp) do
            begin
              typecheckpass(hp.left);
              set_varstate(hp.left,vs_read,[vsf_must_be_valid]);
              if (hdef=nil) then
                begin
                  hdef:=hp.left.resultdef;
                  hnodetype:=hp.left.nodetype;
                end
              else
               begin
                 { If we got a niln we don't know the type yet and need to take the
                   type of the next array element.
                   This is to handle things like [nil,tclass,tclass], see also tw8371 (PFV) }
                 if hnodetype=niln then
                   begin
                     eq:=compare_defs(hp.left.resultdef,hdef,hnodetype);
                     if eq>te_incompatible then
                       begin
                         hdef:=hp.left.resultdef;
                         hnodetype:=hp.left.nodetype;
                       end;
                   end
                 else
                   eq:=compare_defs(hdef,hp.left.resultdef,hp.left.nodetype);
                 if (not varia) and (eq<te_equal) then
                   begin
                     { If both are integers we need to take the type that can hold both
                       defs }
                     if is_integer(hdef) and is_integer(hp.left.resultdef) then
                       begin
                         if is_in_limit(hdef,hp.left.resultdef) then
                           hdef:=hp.left.resultdef;
                       end
                     else
                       if (nf_novariaallowed in flags) then
                         varia:=true;
                   end;
               end;
              inc(len);
              hp:=tarrayconstructornode(hp.right);
            end;
         end;
         { Set the type of empty or varia arrays to void. Also
           do this if the type is array of const/open array
           because those can't be used with setelementdef }
         if not assigned(hdef) or
            varia or
            is_array_of_const(hdef) or
            is_open_array(hdef) then
           hdef:=voidtype;
         resultdef:=tarraydef.create(0,len-1,s32inttype);
         tarraydef(resultdef).elementdef:=hdef;
         include(tarraydef(resultdef).arrayoptions,ado_IsConstructor);
         if varia then
           include(tarraydef(resultdef).arrayoptions,ado_IsVariant);
      end;


    procedure tarrayconstructornode.force_type(def:tdef);
      var
        hp : tarrayconstructornode;
      begin
        tarraydef(resultdef).elementdef:=def;
        include(tarraydef(resultdef).arrayoptions,ado_IsConstructor);
        exclude(tarraydef(resultdef).arrayoptions,ado_IsVariant);
        if assigned(left) then
         begin
           hp:=self;
           while assigned(hp) do
            begin
              inserttypeconv(hp.left,def);
              hp:=tarrayconstructornode(hp.right);
            end;
         end;
      end;


    procedure tarrayconstructornode.insert_typeconvs;
      var
        hp        : tarrayconstructornode;
        dovariant : boolean;
      begin
        dovariant:=(nf_forcevaria in flags) or (ado_isvariant in tarraydef(resultdef).arrayoptions);
        { only pass left tree, right tree contains next construct if any }
        if assigned(left) then
         begin
           hp:=self;
           while assigned(hp) do
            begin
              typecheckpass(hp.left);
              { Insert typeconvs for array of const }
              if dovariant then
                { at this time C varargs are no longer an arrayconstructornode }
                insert_varargstypeconv(hp.left,false);
              hp:=tarrayconstructornode(hp.right);
            end;
         end;
      end;


    function tarrayconstructornode.pass_1 : tnode;
      var
        hp : tarrayconstructornode;
        do_variant:boolean;
      begin
        do_variant:=(nf_forcevaria in flags) or (ado_isvariant in tarraydef(resultdef).arrayoptions);
        result:=nil;
        { Insert required type convs, this must be
          done in pass 1, because the call must be
          typecheckpassed already }
        if assigned(left) then
          begin
            insert_typeconvs;
            { call firstpass for all nodes }
            hp:=self;
            while assigned(hp) do
              begin
                if hp.left<>nil then
                  begin
                    {This check is pessimistic; a call will happen depending
                     on the location in which the elements will be found in
                     pass 2.}
                    if not do_variant then
                      include(current_procinfo.flags,pi_do_call);
                    firstpass(hp.left);
                  end;
                hp:=tarrayconstructornode(hp.right);
              end;
          end;
        expectloc:=LOC_CREFERENCE;
        calcregisters(self,0,0,0);
      end;


    function tarrayconstructornode.docompare(p: tnode): boolean;

    begin
      docompare:=inherited docompare(p);
    end;


{*****************************************************************************
                              TTYPENODE
*****************************************************************************}

    constructor ttypenode.create(def:tdef);
      begin
         inherited create(typen);
         typedef:=def;
         allowed:=false;
      end;


    constructor ttypenode.ppuload(t:tnodetype;ppufile:tcompilerppufile);
      begin
        inherited ppuload(t,ppufile);
        ppufile.getderef(typedefderef);
        allowed:=boolean(ppufile.getbyte);
      end;


    procedure ttypenode.ppuwrite(ppufile:tcompilerppufile);
      begin
        inherited ppuwrite(ppufile);
        ppufile.putderef(typedefderef);
        ppufile.putbyte(byte(allowed));
      end;


    procedure ttypenode.buildderefimpl;
      begin
        inherited buildderefimpl;
        typedefderef.build(typedef);
      end;


    procedure ttypenode.derefimpl;
      begin
        inherited derefimpl;
        typedef:=tdef(typedefderef.resolve);
      end;


    function ttypenode.pass_typecheck:tnode;
      begin
        result:=nil;
        resultdef:=typedef;
        { check if it's valid }
        if typedef.typ = errordef then
          CGMessage(parser_e_illegal_expression);
      end;


    function ttypenode.pass_1 : tnode;
      begin
         result:=nil;
         expectloc:=LOC_VOID;
         { a typenode can't generate code, so we give here
           an error. Else it'll be an abstract error in pass_generate_code.
           Only when the allowed flag is set we don't generate
           an error }
         if not allowed then
          Message(parser_e_no_type_not_allowed_here);
      end;


    function ttypenode.dogetcopy : tnode;
      var
         n : ttypenode;
      begin
         n:=ttypenode(inherited dogetcopy);
         n.allowed:=allowed;
         n.typedef:=typedef;
         result:=n;
      end;


    function ttypenode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p);
      end;


{*****************************************************************************
                              TRTTINODE
*****************************************************************************}


    constructor trttinode.create(def:tstoreddef;rt:trttitype;dt:Trttidatatype);
      begin
         inherited create(rttin);
         rttidef:=def;
         rttitype:=rt;
         rttidatatype:=dt;
      end;


    constructor trttinode.ppuload(t:tnodetype;ppufile:tcompilerppufile);
      begin
        inherited ppuload(t,ppufile);
        ppufile.getderef(rttidefderef);
        rttitype:=trttitype(ppufile.getbyte);
      end;


    procedure trttinode.ppuwrite(ppufile:tcompilerppufile);
      begin
        inherited ppuwrite(ppufile);
        ppufile.putderef(rttidefderef);
        ppufile.putbyte(byte(rttitype));
      end;


    procedure trttinode.buildderefimpl;
      begin
        inherited buildderefimpl;
        rttidefderef.build(rttidef);
      end;


    procedure trttinode.derefimpl;
      begin
        inherited derefimpl;
        rttidef:=tstoreddef(rttidefderef.resolve);
      end;


    function trttinode.dogetcopy : tnode;
      var
         n : trttinode;
      begin
         n:=trttinode(inherited dogetcopy);
         n.rttidef:=rttidef;
         n.rttitype:=rttitype;
         result:=n;
      end;


    function trttinode.pass_typecheck:tnode;
      begin
        { rtti information will be returned as a void pointer }
        result:=nil;
        resultdef:=voidpointertype;
      end;


    function trttinode.pass_1 : tnode;
      begin
        result:=nil;
        expectloc:=LOC_CREFERENCE;
      end;


    function trttinode.docompare(p: tnode): boolean;
      begin
        docompare :=
          inherited docompare(p) and
          (rttidef = trttinode(p).rttidef) and
          (rttitype = trttinode(p).rttitype);
      end;


begin
   cloadnode:=tloadnode;
   cassignmentnode:=tassignmentnode;
   carrayconstructorrangenode:=tarrayconstructorrangenode;
   carrayconstructornode:=tarrayconstructornode;
   ctypenode:=ttypenode;
   crttinode:=trttinode;
end.