fpc/compiler/tree.pas

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

    This units exports some routines to manage the parse tree

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
{$ifdef tp}
  {$E+,N+}
{$endif}
unit tree;

  interface

    uses
       globtype,cobjects,
       symconst,symtable,aasm,cpubase;

    type
       pconstset = ^tconstset;
       tconstset = array[0..31] of byte;

       ttreetyp = (
          addn,     {Represents the + operator.}
          muln,     {Represents the * operator.}
          subn,     {Represents the - operator.}
          divn,     {Represents the div operator.}
          symdifn,       {Represents the >< operator.}
          modn,     {Represents the mod operator.}
          assignn,       {Represents an assignment.}
          loadn,           {Represents the use of a variabele.}
          rangen,         {Represents a range (i.e. 0..9).}
          ltn,       {Represents the < operator.}
          lten,     {Represents the <= operator.}
          gtn,       {Represents the > operator.}
          gten,     {Represents the >= operator.}
          equaln,         {Represents the = operator.}
          unequaln,     {Represents the <> operator.}
          inn,       {Represents the in operator.}
          orn,       {Represents the or operator.}
          xorn,     {Represents the xor operator.}
          shrn,     {Represents the shr operator.}
          shln,     {Represents the shl operator.}
          slashn,         {Represents the / operator.}
          andn,     {Represents the and operator.}
          subscriptn,      {??? Field in a record/object?}
          derefn,         {Dereferences a pointer.}
          addrn,           {Represents the @ operator.}
          doubleaddrn,     {Represents the @@ operator.}
          ordconstn,       {Represents an ordinal value.}
          typeconvn,       {Represents type-conversion/typecast.}
          calln,           {Represents a call node.}
          callparan,       {Represents a parameter.}
          realconstn,      {Represents a real value.}
          fixconstn,       {Represents a fixed value.}
          umminusn,     {Represents a sign change (i.e. -2).}
          asmn,     {Represents an assembler node }
          vecn,     {Represents array indexing.}
          pointerconstn,
          stringconstn,    {Represents a string constant.}
          funcretn,     {Represents the function result var.}
          selfn,           {Represents the self parameter.}
          notn,     {Represents the not operator.}
          inlinen,       {Internal procedures (i.e. writeln).}
          niln,     {Represents the nil pointer.}
          errorn,         {This part of the tree could not be
                            parsed because of a compiler error.}
          typen,           {A type name. Used for i.e. typeof(obj).}
          hnewn,           {The new operation, constructor call.}
          hdisposen,       {The dispose operation with destructor call.}
          newn,     {The new operation, constructor call.}
          simpledisposen,  {The dispose operation.}
          setelementn,     {A set element(s) (i.e. [a,b] and also [a..b]).}
          setconstn,       {A set constant (i.e. [1,2]).}
          blockn,         {A block of statements.}
          statementn,      {One statement in a block of nodes.}
          loopn,           { used in genloopnode, must be converted }
          ifn,       {An if statement.}
          breakn,         {A break statement.}
          continuen,       {A continue statement.}
          repeatn,       {A repeat until block.}
          whilen,         {A while do statement.}
          forn,     {A for loop.}
          exitn,           {An exit statement.}
          withn,           {A with statement.}
          casen,           {A case statement.}
          labeln,         {A label.}
          goton,           {A goto statement.}
          simplenewn,      {The new operation.}
          tryexceptn,      {A try except block.}
          raisen,         {A raise statement.}
          switchesn,       {??? Currently unused...}
          tryfinallyn,     {A try finally statement.}
          onn,       { for an on statement in exception code }
          isn,       {Represents the is operator.}
          asn,       {Represents the as typecast.}
          caretn,         {Represents the ^ operator.}
          failn,           {Represents the fail statement.}
          starstarn,       {Represents the ** operator exponentiation }
          procinlinen,     {Procedures that can be inlined }
          arrayconstructn, {Construction node for [...] parsing}
          arrayconstructrangen, {Range element to allow sets in array construction tree}
          { added for optimizations where we cannot suppress }
          nothingn,
          loadvmtn
       );

       tconverttype = (
          tc_equal,
          tc_not_possible,
          tc_string_2_string,
          tc_char_2_string,
          tc_pchar_2_string,
          tc_cchar_2_pchar,
          tc_cstring_2_pchar,
          tc_ansistring_2_pchar,
          tc_string_2_chararray,
          tc_chararray_2_string,
          tc_array_2_pointer,
          tc_pointer_2_array,
          tc_int_2_int,
          tc_int_2_bool,
          tc_bool_2_bool,
          tc_bool_2_int,
          tc_real_2_real,
          tc_int_2_real,
          tc_int_2_fix,
          tc_real_2_fix,
          tc_fix_2_real,
          tc_proc_2_procvar,
          tc_arrayconstructor_2_set,
          tc_load_smallset,
          tc_cord_2_pointer
       );

       { allows to determine which elementes are to be replaced }
       tdisposetyp = (dt_nothing,dt_leftright,dt_left,dt_leftrighthigh,
                      dt_mbleft,dt_typeconv,dt_inlinen,dt_leftrightmethod,
                      dt_mbleft_and_method,dt_loop,dt_case,dt_with,dt_onn);

      { different assignment types }

      tassigntyp = (at_normal,at_plus,at_minus,at_star,at_slash);

      pcaserecord = ^tcaserecord;
      tcaserecord = record

          { range }
          _low,_high : longint;

          { only used by gentreejmp }
          _at : pasmlabel;

          { label of instruction }
          statement : pasmlabel;

          { is this the first of an case entry, needed to release statement
            label (PFV) }
          firstlabel : boolean;

          { left and right tree node }
          less,greater : pcaserecord;
       end;

       ptree = ^ttree;
       ttree = record
          error : boolean;
          disposetyp : tdisposetyp;
          { is true, if the right and left operand are swaped }
          swaped : boolean;

          { the location of the result of this node }
          location : tlocation;

          { the number of registers needed to evalute the node }
          registers32,registersfpu : longint;  { must be longint !!!! }
{$ifdef SUPPORT_MMX}
          registersmmx : longint;
{$endif SUPPORT_MMX}
          left,right : ptree;
          resulttype : pdef;
          fileinfo : tfileposinfo;
          localswitches : tlocalswitches;
          isproperty : boolean;
{$ifdef extdebug}
          firstpasscount : longint;
{$endif extdebug}
{$ifdef TEMPREGDEBUG}
          usableregs : longint;
{$endif TEMPREGDEBUG}
{$ifdef EXTTEMPREGDEBUG}
          reallyusedregs : longint;
{$endif EXTTEMPREGDEBUG}
{$ifdef TEMPS_NOT_PUSH}
          temp_offset : longint;
{$endif TEMPS_NOT_PUSH}
          case treetype : ttreetyp of
             addn : (use_strconcat : boolean;string_typ : tstringtype);
             callparan : (is_colon_para : boolean;exact_match_found,
                          convlevel1found,convlevel2found:boolean;hightree:ptree);
             assignn : (assigntyp : tassigntyp;concat_string : boolean);
             loadn : (symtableentry : psym;symtable : psymtable;
                      is_absolute,is_first : boolean);
             calln : (symtableprocentry : pprocsym;
                      symtableproc : psymtable;procdefinition : pabstractprocdef;
                      methodpointer : ptree;
                      no_check,unit_specific,
                      return_value_used,static_call : boolean);
             addrn : (procvarload:boolean);
             ordconstn : (value : longint);
             realconstn : (value_real : bestreal;lab_real : pasmlabel);
             fixconstn : (value_fix: longint);
             funcretn : (funcretprocinfo : pointer;retdef : pdef);
             subscriptn : (vs : pvarsym);
             vecn : (memindex,memseg:boolean;callunique : boolean);
             stringconstn : (value_str : pchar;length : longint; lab_str : pasmlabel;stringtype : tstringtype);
             typeconvn : (convtyp : tconverttype;explizit : boolean);
             typen : (typenodetype : pdef;typenodesym:ptypesym);
             inlinen : (inlinenumber : byte;inlineconst:boolean);
             procinlinen : (inlinetree:ptree;inlineprocsym:pprocsym;retoffset,para_offset,para_size : longint);
             setconstn : (value_set : pconstset;lab_set:pasmlabel);
             loopn : (t1,t2 : ptree;backward : boolean);
             asmn : (p_asm : paasmoutput;object_preserved : boolean);
             casen : (nodes : pcaserecord;elseblock : ptree);
             labeln,goton : (labelnr : pasmlabel);
             withn : (withsymtable : pwithsymtable;tablecount : longint;withreference:preference;islocal:boolean);
             onn : (exceptsymtable : psymtable;excepttype : pobjectdef);
             arrayconstructn : (cargs,cargswap,forcevaria,novariaallowed: boolean;constructdef:pdef);
           end;

    function gennode(t : ttreetyp;l,r : ptree) : ptree;
    function genlabelnode(t : ttreetyp;nr : pasmlabel) : ptree;
    function genloadnode(v : pvarsym;st : psymtable) : ptree;
    function genloadcallnode(v: pprocsym;st: psymtable): ptree;
    function genloadmethodcallnode(v: pprocsym;st: psymtable; mp:ptree): ptree;
    function gensinglenode(t : ttreetyp;l : ptree) : ptree;
    function gensubscriptnode(varsym : pvarsym;l : ptree) : ptree;
    function genordinalconstnode(v : longint;def : pdef) : ptree;
    function genpointerconstnode(v : longint;def : pdef) : ptree;
    function genfixconstnode(v : longint;def : pdef) : ptree;
    function gentypeconvnode(node : ptree;t : pdef) : ptree;
    function gentypenode(t : pdef;sym:ptypesym) : ptree;
    function gencallparanode(expr,next : ptree) : ptree;
    function genrealconstnode(v : bestreal;def : pdef) : ptree;
    function gencallnode(v : pprocsym;st : psymtable) : ptree;
    function genmethodcallnode(v : pprocsym;st : psymtable;mp : ptree) : ptree;

    { allow pchar or string for defining a pchar node }
    function genstringconstnode(const s : string) : ptree;
    { length is required for ansistrings }
    function genpcharconstnode(s : pchar;length : longint) : ptree;
    { helper routine for conststring node }
    function getpcharcopy(p : ptree) : pchar;

    function genzeronode(t : ttreetyp) : ptree;
    function geninlinenode(number : byte;is_const:boolean;l : ptree) : ptree;
    function genprocinlinenode(callp,code : ptree) : ptree;
    function gentypedconstloadnode(sym : ptypedconstsym;st : psymtable) : ptree;
    function genenumnode(v : penumsym) : ptree;
    function genselfnode(_class : pdef) : ptree;
    function gensetconstnode(s : pconstset;settype : psetdef) : ptree;
    function genloopnode(t : ttreetyp;l,r,n1: ptree;back : boolean) : ptree;
    function genasmnode(p_asm : paasmoutput) : ptree;
    function gencasenode(l,r : ptree;nodes : pcaserecord) : ptree;
    function genwithnode(symtable : pwithsymtable;l,r : ptree;count : longint) : ptree;

    function getcopy(p : ptree) : ptree;

    function equal_trees(t1,t2 : ptree) : boolean;

    procedure swaptree(p:Ptree);
    procedure disposetree(p : ptree);
    procedure putnode(p : ptree);
    function getnode : ptree;
    procedure clear_location(var loc : tlocation);
    procedure set_location(var destloc,sourceloc : tlocation);
    procedure swap_location(var destloc,sourceloc : tlocation);
    procedure set_file_line(from,_to : ptree);
    procedure set_tree_filepos(p : ptree;const filepos : tfileposinfo);
{$ifdef extdebug}
    procedure compare_trees(oldp,p : ptree);
    const
       maxfirstpasscount : longint = 0;
{$endif extdebug}

    { sets the callunique flag, if the node is a vecn, }
    { takes care of type casts etc.                 }
    procedure set_unique(p : ptree);

    { sets funcret_is_valid to true, if p contains a funcref node }
    procedure set_funcret_is_valid(p : ptree);

    { gibt den ordinalen Werten der Node zurueck oder falls sie }
    { keinen ordinalen Wert hat, wird ein Fehler erzeugt        }
    function get_ordinal_value(p : ptree) : longint;

    function is_constnode(p : ptree) : boolean;
    { true, if p is a pointer to a const int value }
    function is_constintnode(p : ptree) : boolean;
    function is_constboolnode(p : ptree) : boolean;
    function is_constrealnode(p : ptree) : boolean;
    function is_constcharnode(p : ptree) : boolean;
    function str_length(p : ptree) : longint;
    function is_emptyset(p : ptree):boolean;

    { counts the labels }
    function case_count_labels(root : pcaserecord) : longint;
    { searches the highest label }
    function case_get_max(root : pcaserecord) : longint;
    { searches the lowest label }
    function case_get_min(root : pcaserecord) : longint;

    type
      pptree = ^ptree;

{$ifdef TEMPREGDEBUG}
    const
      curptree : pptree = nil;
{$endif TEMPREGDEBUG}

{$I innr.inc}

  implementation

    uses
       systems,
       globals,verbose,files,types,hcodegen;


    function getnode : ptree;

      var
         hp : ptree;

      begin
         new(hp);
         { makes error tracking easier }
         fillchar(hp^,sizeof(ttree),0);
         { reset }
         hp^.location.loc:=LOC_INVALID;
         { save local info }
         hp^.fileinfo:=aktfilepos;
         hp^.localswitches:=aktlocalswitches;
         getnode:=hp;
      end;


    procedure putnode(p : ptree);
      begin
         { clean up the contents of a node }
         case p^.treetype of
          asmn : if assigned(p^.p_asm) then
                  dispose(p^.p_asm,done);
  stringconstn : begin
                   ansistringdispose(p^.value_str,p^.length);
                 end;
     setconstn : begin
                   if assigned(p^.value_set) then
                     dispose(p^.value_set);
                 end;
         end;
{$ifdef extdebug}
         if p^.firstpasscount>maxfirstpasscount then
            maxfirstpasscount:=p^.firstpasscount;
{$endif extdebug}
         dispose(p);
      end;

    function getcopy(p : ptree) : ptree;

      var
         hp : ptree;

      begin
         if not assigned(p) then
          begin
            getcopy:=nil;
            exit;
          end;
         hp:=getnode;
         hp^:=p^;
         case p^.disposetyp of
            dt_leftright :
              begin
                 if assigned(p^.left) then
                   hp^.left:=getcopy(p^.left);
                 if assigned(p^.right) then
                   hp^.right:=getcopy(p^.right);
              end;
            dt_leftrighthigh :
              begin
                 if assigned(p^.left) then
                   hp^.left:=getcopy(p^.left);
                 if assigned(p^.right) then
                   hp^.right:=getcopy(p^.right);
                 if assigned(p^.hightree) then
                   hp^.left:=getcopy(p^.hightree);
              end;
            dt_leftrightmethod :
              begin
                 if assigned(p^.left) then
                   hp^.left:=getcopy(p^.left);
                 if assigned(p^.right) then
                   hp^.right:=getcopy(p^.right);
                 if assigned(p^.methodpointer) then
                   hp^.left:=getcopy(p^.methodpointer);
              end;
            dt_nothing : ;
            dt_left    :
              if assigned(p^.left) then
                hp^.left:=getcopy(p^.left);
            dt_mbleft :
              if assigned(p^.left) then
                hp^.left:=getcopy(p^.left);
            dt_mbleft_and_method :
              begin
                 if assigned(p^.left) then
                   hp^.left:=getcopy(p^.left);
                 hp^.methodpointer:=getcopy(p^.methodpointer);
              end;
            dt_loop :
              begin
                 if assigned(p^.left) then
                   hp^.left:=getcopy(p^.left);
                 if assigned(p^.right) then
                   hp^.right:=getcopy(p^.right);
                 if assigned(p^.t1) then
                   hp^.t1:=getcopy(p^.t1);
                 if assigned(p^.t2) then
                   hp^.t2:=getcopy(p^.t2);
              end;
            dt_typeconv : hp^.left:=getcopy(p^.left);
            dt_inlinen :
              if assigned(p^.left) then
                hp^.left:=getcopy(p^.left);
            else internalerror(11);
         end;
       { now check treetype }
         case p^.treetype of
  stringconstn : begin
                   hp^.value_str:=getpcharcopy(p);
                   hp^.length:=p^.length;
                 end;
     setconstn : begin
                   new(hp^.value_set);
                   hp^.value_set:=p^.value_set;
                 end;
         end;
         getcopy:=hp;
      end;

    procedure deletecaselabels(p : pcaserecord);

      begin
         if assigned(p^.greater) then
           deletecaselabels(p^.greater);
         if assigned(p^.less) then
           deletecaselabels(p^.less);
         freelabel(p^._at);
         if p^.firstlabel then
          freelabel(p^.statement);
         dispose(p);
      end;

    procedure swaptree(p:Ptree);

    var swapp:Ptree;

    begin
        swapp:=p^.right;
        p^.right:=p^.left;
        p^.left:=swapp;
        p^.swaped:=not(p^.swaped);
    end;


    procedure disposetree(p : ptree);

      var
         symt : pwithsymtable;
         i : longint;

      begin
         if not(assigned(p)) then
           exit;
         if not(p^.treetype in [addn..loadvmtn]) then
           internalerror(26219);
         case p^.disposetyp of
            dt_leftright :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
              end;
            dt_leftrighthigh :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 if assigned(p^.hightree) then
                   disposetree(p^.hightree);
              end;
            dt_leftrightmethod :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 if assigned(p^.methodpointer) then
                   disposetree(p^.methodpointer);
              end;
            dt_case :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 if assigned(p^.nodes) then
                   deletecaselabels(p^.nodes);
                 if assigned(p^.elseblock) then
                   disposetree(p^.elseblock);
              end;
            dt_nothing : ;
            dt_left    :
              if assigned(p^.left) then
                disposetree(p^.left);
            dt_mbleft :
              if assigned(p^.left) then
                disposetree(p^.left);
            dt_mbleft_and_method :
              begin
                 if assigned(p^.left) then disposetree(p^.left);
                 disposetree(p^.methodpointer);
              end;
            dt_typeconv : disposetree(p^.left);
            dt_inlinen :
              if assigned(p^.left) then
                disposetree(p^.left);
            dt_loop :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 if assigned(p^.t1) then
                   disposetree(p^.t1);
                 if assigned(p^.t2) then
                   disposetree(p^.t2);
              end;
            dt_onn:
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 if assigned(p^.exceptsymtable) then
                   dispose(p^.exceptsymtable,done);
              end;
            dt_with :
              begin
                 if assigned(p^.left) then
                   disposetree(p^.left);
                 if assigned(p^.right) then
                   disposetree(p^.right);
                 symt:=p^.withsymtable;
                 for i:=1 to p^.tablecount do
                   begin
                      if assigned(symt) then
                        begin
                           p^.withsymtable:=pwithsymtable(symt^.next);
                           dispose(symt,done);
                        end;
                      symt:=p^.withsymtable;
                   end;
              end;
            else internalerror(12);
         end;
         putnode(p);
      end;

    procedure set_file_line(from,_to : ptree);

      begin
         if assigned(from) then
           _to^.fileinfo:=from^.fileinfo;
      end;

   procedure set_tree_filepos(p : ptree;const filepos : tfileposinfo);
     begin
        p^.fileinfo:=filepos;
     end;

   function genwithnode(symtable : pwithsymtable;l,r : ptree;count : longint) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_with;
         p^.treetype:=withn;
         p^.left:=l;
         p^.right:=r;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         p^.withsymtable:=symtable;
         p^.tablecount:=count;
         p^.withreference:=nil;
         p^.islocal:=false;
         set_file_line(l,p);
         genwithnode:=p;
      end;

    function genfixconstnode(v : longint;def : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=fixconstn;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=def;
         p^.value:=v;
         genfixconstnode:=p;
      end;

    function gencallparanode(expr,next : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_leftrighthigh;
         p^.treetype:=callparan;
         p^.left:=expr;
         p^.right:=next;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.registersfpu:=0;
         p^.resulttype:=nil;
         p^.exact_match_found:=false;
         p^.convlevel1found:=false;
         p^.convlevel2found:=false;
         p^.is_colon_para:=false;
         p^.hightree:=nil;
         set_file_line(expr,p);
         gencallparanode:=p;
      end;

    function gennode(t : ttreetyp;l,r : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_leftright;
         p^.treetype:=t;
         p^.left:=l;
         p^.right:=r;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         gennode:=p;
      end;

    function gencasenode(l,r : ptree;nodes : pcaserecord) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_case;
         p^.treetype:=casen;
         p^.left:=l;
         p^.right:=r;
         p^.nodes:=nodes;
         p^.registers32:=0;
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         set_file_line(l,p);
         gencasenode:=p;
      end;

    function genloopnode(t : ttreetyp;l,r,n1 : ptree;back : boolean) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_loop;
         p^.treetype:=t;
         p^.left:=l;
         p^.right:=r;
         p^.t1:=n1;
         p^.t2:=nil;
         p^.registers32:=0;
         p^.backward:=back;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         set_file_line(l,p);
         genloopnode:=p;
      end;

    function genordinalconstnode(v : longint;def : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=ordconstn;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=def;
         p^.value:=v;
         if p^.resulttype^.deftype=orddef then
          testrange(p^.resulttype,p^.value);
         genordinalconstnode:=p;
      end;

    function genpointerconstnode(v : longint;def : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=pointerconstn;
         p^.registers32:=0;
         { p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=def;
         p^.value:=v;
         genpointerconstnode:=p;
      end;

    function genenumnode(v : penumsym) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=ordconstn;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=v^.definition;
         p^.value:=v^.value;
         testrange(p^.resulttype,p^.value);
         genenumnode:=p;
      end;


    function genrealconstnode(v : bestreal;def : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=realconstn;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=def;
         p^.value_real:=v;
         p^.lab_real:=nil;
         genrealconstnode:=p;
      end;


    function genstringconstnode(const s : string) : ptree;

      var
         p : ptree;
         l : longint;
      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=stringconstn;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         l:=length(s);
         p^.length:=l;
         { stringdup write even past a #0 }
         getmem(p^.value_str,l+1);
         move(s[1],p^.value_str^,l);
         p^.value_str[l]:=#0;
         p^.lab_str:=nil;
         if cs_ansistrings in aktlocalswitches then
          begin
            p^.stringtype:=st_ansistring;
            p^.resulttype:=cansistringdef;
          end
         else
          begin
            p^.stringtype:=st_shortstring;
            p^.resulttype:=cshortstringdef;
          end;
         genstringconstnode:=p;
      end;

    function getpcharcopy(p : ptree) : pchar;
      var
         pc : pchar;
      begin
         pc:=nil;
         getmem(pc,p^.length+1);
         if pc=nil then
           Message(general_f_no_memory_left);
         move(p^.value_str^,pc^,p^.length+1);
         getpcharcopy:=pc;
      end;


    function genpcharconstnode(s : pchar;length : longint) : ptree;
      var
         p : ptree;
      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=stringconstn;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.length:=length;
         if (cs_ansistrings in aktlocalswitches) or
            (length>255) then
          begin
            p^.stringtype:=st_ansistring;
            p^.resulttype:=cansistringdef;
          end
         else
          begin
            p^.stringtype:=st_shortstring;
            p^.resulttype:=cshortstringdef;
          end;
         p^.value_str:=s;
         p^.lab_str:=nil;
         genpcharconstnode:=p;
      end;


    function gensinglenode(t : ttreetyp;l : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_left;
         p^.treetype:=t;
         p^.left:=l;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         gensinglenode:=p;
      end;

    function genasmnode(p_asm : paasmoutput) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=asmn;
         p^.registers32:=4;
         p^.p_asm:=p_asm;
         p^.object_preserved:=false;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=8;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=8;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         genasmnode:=p;
      end;

    function genloadnode(v : pvarsym;st : psymtable) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=loadn;
         p^.resulttype:=v^.definition;
         p^.symtableentry:=v;
         p^.symtable:=st;
         p^.is_first := False;
         { method pointer load nodes can use the left subtree }
         p^.disposetyp:=dt_left;
         p^.left:=nil;
         genloadnode:=p;
      end;

    function genloadcallnode(v: pprocsym;st: psymtable): ptree;
      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=loadn;
         p^.left:=nil;
         p^.resulttype:=v^.definition;
         p^.symtableentry:=v;
         p^.symtable:=st;
         p^.is_first := False;
         p^.disposetyp:=dt_nothing;
         genloadcallnode:=p;
      end;

    function genloadmethodcallnode(v: pprocsym;st: psymtable; mp:ptree): ptree;
      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=loadn;
         p^.left:=nil;
         p^.resulttype:=v^.definition;
         p^.symtableentry:=v;
         p^.symtable:=st;
         p^.is_first := False;
         p^.disposetyp:=dt_left;
         p^.left:=mp;
         genloadmethodcallnode:=p;
      end;


    function gentypedconstloadnode(sym : ptypedconstsym;st : psymtable) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=loadn;
         p^.left:=nil;
         p^.resulttype:=sym^.definition;
         p^.symtableentry:=sym;
         p^.symtable:=st;
         p^.disposetyp:=dt_nothing;
         gentypedconstloadnode:=p;
      end;

    function gentypeconvnode(node : ptree;t : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_typeconv;
         p^.treetype:=typeconvn;
         p^.left:=node;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.convtyp:=tc_equal;
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=t;
         p^.explizit:=false;
         set_file_line(node,p);
         gentypeconvnode:=p;
      end;

    function gentypenode(t : pdef;sym:ptypesym) : ptree;
      var
         p : ptree;
      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=typen;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=generrordef;
         p^.typenodetype:=t;
         p^.typenodesym:=sym;
         gentypenode:=p;
      end;

    function gencallnode(v : pprocsym;st : psymtable) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=calln;
         p^.symtableprocentry:=v;
         p^.symtableproc:=st;
         p^.unit_specific:=false;
         p^.no_check:=false;
         p^.return_value_used:=true;
         p^.disposetyp := dt_leftrightmethod;
         p^.methodpointer:=nil;
         p^.left:=nil;
         p^.right:=nil;
         p^.procdefinition:=nil;
         gencallnode:=p;
      end;

    function genmethodcallnode(v : pprocsym;st : psymtable;mp : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.treetype:=calln;
         p^.return_value_used:=true;
         p^.symtableprocentry:=v;
         p^.symtableproc:=st;
         p^.disposetyp:=dt_leftrightmethod;
         p^.left:=nil;
         p^.right:=nil;
         p^.methodpointer:=mp;
         p^.procdefinition:=nil;
         genmethodcallnode:=p;
      end;

    function gensubscriptnode(varsym : pvarsym;l : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_left;
         p^.treetype:=subscriptn;
         p^.left:=l;
         p^.registers32:=0;
         p^.vs:=varsym;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         gensubscriptnode:=p;
      end;

   function genzeronode(t : ttreetyp) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=t;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         genzeronode:=p;
      end;

   function genlabelnode(t : ttreetyp;nr : pasmlabel) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=t;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         { for security }
         { nr^.is_used:=true;}
         p^.labelnr:=nr;
         genlabelnode:=p;
      end;

    function genselfnode(_class : pdef) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=selfn;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=_class;
         genselfnode:=p;
      end;

   function geninlinenode(number : byte;is_const:boolean;l : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_inlinen;
         p^.treetype:=inlinen;
         p^.left:=l;
         p^.inlinenumber:=number;
         p^.inlineconst:=is_const;
         p^.registers32:=0;
{        p^.registers16:=0;
         p^.registers8:=0; }
         p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=nil;
         geninlinenode:=p;
      end;


      { uses the callnode to create the new procinline node }
    function genprocinlinenode(callp,code : ptree) : ptree;

      var
         p : ptree;

      begin
         p:=getnode;
         p^.disposetyp:=dt_nothing;
         p^.treetype:=procinlinen;
         p^.inlineprocsym:=callp^.symtableprocentry;
         p^.retoffset:=-4; { less dangerous as zero (PM) }
         p^.para_offset:=0;
         p^.para_size:=p^.inlineprocsym^.definition^.para_size;
         if ret_in_param(p^.inlineprocsym^.definition^.retdef) then
           p^.para_size:=p^.para_size+target_os.size_of_pointer;
         { copy args }
         p^.inlinetree:=code;
         p^.registers32:=code^.registers32;
         p^.registersfpu:=code^.registersfpu;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=p^.inlineprocsym^.definition^.retdef;
         genprocinlinenode:=p;
      end;

   function gensetconstnode(s : pconstset;settype : psetdef) : ptree;

     var
        p : ptree;

     begin
        p:=getnode;
        p^.disposetyp:=dt_nothing;
        p^.treetype:=setconstn;
        p^.registers32:=0;
        p^.registersfpu:=0;
{$ifdef SUPPORT_MMX}
         p^.registersmmx:=0;
{$endif SUPPORT_MMX}
         p^.resulttype:=settype;
         p^.left:=nil;
         new(p^.value_set);
         p^.value_set^:=s^;
         gensetconstnode:=p;
      end;

{$ifdef extdebug}
    procedure compare_trees(oldp,p : ptree);

      var
         error_found : boolean;

      begin
          if oldp^.resulttype<>p^.resulttype then
            begin
               error_found:=true;
               if is_equal(oldp^.resulttype,p^.resulttype) then
                 comment(v_debug,'resulttype fields are different but equal')
               else
                 comment(v_warning,'resulttype fields are really different');
            end;
         if oldp^.treetype<>p^.treetype then
           begin
              comment(v_warning,'treetype field different');
              error_found:=true;
           end
         else
           comment(v_debug,' treetype '+tostr(longint(oldp^.treetype)));
         if oldp^.error<>p^.error then
           begin
              comment(v_warning,'error field different');
              error_found:=true;
           end;
         if oldp^.disposetyp<>p^.disposetyp then
           begin
              comment(v_warning,'disposetyp field different');
              error_found:=true;
           end;
         { is true, if the right and left operand are swaped }
         if oldp^.swaped<>p^.swaped then
           begin
              comment(v_warning,'swaped field different');
              error_found:=true;
           end;

         { the location of the result of this node }
         if oldp^.location.loc<>p^.location.loc then
           begin
              comment(v_warning,'location.loc field different');
              error_found:=true;
           end;

          { the number of registers needed to evalute the node }
          if oldp^.registers32<>p^.registers32 then
           begin
              comment(v_warning,'registers32 field different');
              comment(v_warning,' old '+tostr(oldp^.registers32)+'<> new '+tostr(p^.registers32));
              error_found:=true;
           end;
          if oldp^.registersfpu<>p^.registersfpu then
           begin
              comment(v_warning,'registersfpu field different');
              error_found:=true;
           end;
{$ifdef SUPPORT_MMX}
          if oldp^.registersmmx<>p^.registersmmx then
           begin
              comment(v_warning,'registersmmx field different');
              error_found:=true;
           end;
{$endif SUPPORT_MMX}
          if oldp^.left<>p^.left then
           begin
              comment(v_warning,'left field different');
              error_found:=true;
           end;
          if oldp^.right<>p^.right then
           begin
              comment(v_warning,'right field different');
              error_found:=true;
           end;
          if oldp^.fileinfo.line<>p^.fileinfo.line then
            begin
               comment(v_warning,'fileinfo.line field different');
               error_found:=true;
            end;
          if oldp^.fileinfo.column<>p^.fileinfo.column then
            begin
               comment(v_warning,'fileinfo.column field different');
               error_found:=true;
            end;
          if oldp^.fileinfo.fileindex<>p^.fileinfo.fileindex then
            begin
               comment(v_warning,'fileinfo.fileindex field different');
               error_found:=true;
            end;
          if oldp^.localswitches<>p^.localswitches then
            begin
               comment(v_warning,'localswitches field different');
               error_found:=true;
            end;
{$ifdef extdebug}
          if oldp^.firstpasscount<>p^.firstpasscount then
            begin
               comment(v_warning,'firstpasscount field different');
               error_found:=true;
            end;
{$endif extdebug}
          if oldp^.treetype=p^.treetype then
          case oldp^.treetype of
             addn :
             begin
                if oldp^.use_strconcat<>p^.use_strconcat then
                  begin
                     comment(v_warning,'use_strconcat field different');
                     error_found:=true;
                  end;
                if oldp^.string_typ<>p^.string_typ then
                  begin
                     comment(v_warning,'stringtyp field different');
                     error_found:=true;
                  end;
             end;
             callparan :
             {(is_colon_para : boolean;exact_match_found : boolean);}
             begin
                if oldp^.is_colon_para<>p^.is_colon_para then
                  begin
                     comment(v_warning,'use_strconcat field different');
                     error_found:=true;
                  end;
                if oldp^.exact_match_found<>p^.exact_match_found then
                  begin
                     comment(v_warning,'exact_match_found field different');
                     error_found:=true;
                  end;
             end;
             assignn :
             {(assigntyp : tassigntyp;concat_string : boolean);}
             begin
                if oldp^.assigntyp<>p^.assigntyp then
                  begin
                     comment(v_warning,'assigntyp field different');
                     error_found:=true;
                  end;
                if oldp^.concat_string<>p^.concat_string then
                  begin
                     comment(v_warning,'concat_string field different');
                     error_found:=true;
                  end;
             end;
             loadn :
             {(symtableentry : psym;symtable : psymtable;
                      is_absolute,is_first : boolean);}
             begin
                if oldp^.symtableentry<>p^.symtableentry then
                  begin
                     comment(v_warning,'symtableentry field different');
                     error_found:=true;
                  end;
                if oldp^.symtable<>p^.symtable then
                  begin
                     comment(v_warning,'symtable field different');
                     error_found:=true;
                  end;
                if oldp^.is_absolute<>p^.is_absolute then
                  begin
                     comment(v_warning,'is_absolute field different');
                     error_found:=true;
                  end;
                if oldp^.is_first<>p^.is_first then
                  begin
                     comment(v_warning,'is_first field different');
                     error_found:=true;
                  end;
             end;
             calln :
             {(symtableprocentry : pprocsym;
                      symtableproc : psymtable;procdefinition : pprocdef;
                      methodpointer : ptree;
                      no_check,unit_specific : boolean);}
             begin
                if oldp^.symtableprocentry<>p^.symtableprocentry then
                  begin
                     comment(v_warning,'symtableprocentry field different');
                     error_found:=true;
                  end;
                if oldp^.symtableproc<>p^.symtableproc then
                  begin
                     comment(v_warning,'symtableproc field different');
                     error_found:=true;
                  end;
                if oldp^.procdefinition<>p^.procdefinition then
                  begin
                     comment(v_warning,'procdefinition field different');
                     error_found:=true;
                  end;
                if oldp^.methodpointer<>p^.methodpointer then
                  begin
                     comment(v_warning,'methodpointer field different');
                     error_found:=true;
                  end;
                if oldp^.no_check<>p^.no_check then
                  begin
                     comment(v_warning,'no_check field different');
                     error_found:=true;
                  end;
                if oldp^.unit_specific<>p^.unit_specific then
                  begin
                     error_found:=true;
                     comment(v_warning,'unit_specific field different');
                  end;
             end;
             ordconstn :
               begin
                  if oldp^.value<>p^.value then
                  begin
                     comment(v_warning,'value field different');
                     error_found:=true;
                  end;
               end;
             realconstn :
               begin
                  if oldp^.value_real<>p^.value_real then
                  begin
                     comment(v_warning,'valued field different');
                     error_found:=true;
                  end;
                  if oldp^.lab_real<>p^.lab_real then
                  begin
                     comment(v_warning,'labnumber field different');
                     error_found:=true;
                  end;
                  { if oldp^.realtyp<>p^.realtyp then
                  begin
                     comment(v_warning,'realtyp field different');
                     error_found:=true;
                  end; }
               end;
           end;
         if not error_found then
           comment(v_warning,'did not find difference in trees');

      end;
{$endif extdebug}

    function equal_trees(t1,t2 : ptree) : boolean;

      begin
         if t1^.treetype=t2^.treetype then
           begin
              case t1^.treetype of
                 addn,
                 muln,
                 equaln,
                 orn,
                 xorn,
                 andn,
                 unequaln:
                   begin
                      equal_trees:=(equal_trees(t1^.left,t2^.left) and
                                    equal_trees(t1^.right,t2^.right)) or
                                   (equal_trees(t1^.right,t2^.left) and
                                    equal_trees(t1^.left,t2^.right));
                   end;
                 subn,
                 divn,
                 modn,
                 assignn,
                 ltn,
                 lten,
                 gtn,
                 gten,
                 inn,
                 shrn,
                 shln,
                 slashn,
                 rangen:
                   begin
                      equal_trees:=(equal_trees(t1^.left,t2^.left) and
                                    equal_trees(t1^.right,t2^.right));
                   end;
                 umminusn,
                 notn,
                 derefn,
                 addrn:
                   begin
                      equal_trees:=(equal_trees(t1^.left,t2^.left));
                   end;
                loadn:
                   begin
                      equal_trees:=(t1^.symtableentry=t2^.symtableentry)
                        { not necessary
                                     and (t1^.symtable=t2^.symtable)};
                   end;
                {

                   subscriptn,
                   ordconstn,typeconvn,calln,callparan,
                   realconstn,asmn,vecn,
                   stringconstn,funcretn,selfn,
                   inlinen,niln,errorn,
                   typen,hnewn,hdisposen,newn,
                   disposen,setelen,setconstrn
                }
                else equal_trees:=false;
             end;
          end
        else
          equal_trees:=false;
     end;

    procedure set_unique(p : ptree);

      begin
         if assigned(p) then
           begin
              case p^.treetype of
                 vecn:
                    p^.callunique:=true;
                 typeconvn,subscriptn,derefn:
                    set_unique(p^.left);
              end;
           end;
      end;

    procedure set_funcret_is_valid(p : ptree);

      begin
         if assigned(p) then
           begin
              case p^.treetype of
                 funcretn:
                    procinfo^.funcret_is_valid:=true;
                 vecn,typeconvn,subscriptn,derefn:
                    set_funcret_is_valid(p^.left);
              end;
           end;
      end;

    procedure clear_location(var loc : tlocation);

      begin
        loc.loc:=LOC_INVALID;
      end;

    {This is needed if you want to be able to delete the string with the nodes !!}
    procedure set_location(var destloc,sourceloc : tlocation);

      begin
        destloc:= sourceloc;
      end;

    procedure swap_location(var destloc,sourceloc : tlocation);

      var
         swapl : tlocation;

      begin
         swapl := destloc;
         destloc := sourceloc;
         sourceloc := swapl;
      end;


    function get_ordinal_value(p : ptree) : longint;
      begin
         if p^.treetype=ordconstn then
           get_ordinal_value:=p^.value
         else
           begin
             Message(type_e_ordinal_expr_expected);
             get_ordinal_value:=0;
           end;
      end;


    function is_constnode(p : ptree) : boolean;
      begin
        is_constnode:=(p^.treetype in [ordconstn,realconstn,stringconstn,fixconstn,setconstn]);
      end;


    function is_constintnode(p : ptree) : boolean;
      begin
         is_constintnode:=(p^.treetype=ordconstn) and is_integer(p^.resulttype);
      end;


    function is_constcharnode(p : ptree) : boolean;

      begin
         is_constcharnode:=(p^.treetype=ordconstn) and is_char(p^.resulttype);
      end;

    function is_constrealnode(p : ptree) : boolean;

      begin
         is_constrealnode:=(p^.treetype=realconstn);
      end;

    function is_constboolnode(p : ptree) : boolean;

      begin
         is_constboolnode:=(p^.treetype=ordconstn) and is_boolean(p^.resulttype);
      end;

    function str_length(p : ptree) : longint;

      begin
         str_length:=p^.length;
      end;


    function is_emptyset(p : ptree):boolean;
    {
      return true if set s is empty
    }
      var
        i : longint;
      begin
        i:=0;
        if p^.treetype=setconstn then
         begin
           while (i<32) and (p^.value_set^[i]=0) do
            inc(i);
         end;
        is_emptyset:=(i=32);
      end;


{*****************************************************************************
                              Case Helpers
*****************************************************************************}

    function case_count_labels(root : pcaserecord) : longint;
      var
         _l : longint;

      procedure count(p : pcaserecord);
        begin
           inc(_l);
           if assigned(p^.less) then
             count(p^.less);
           if assigned(p^.greater) then
             count(p^.greater);
        end;

      begin
         _l:=0;
         count(root);
         case_count_labels:=_l;
      end;


    function case_get_max(root : pcaserecord) : longint;
      var
         hp : pcaserecord;
      begin
         hp:=root;
         while assigned(hp^.greater) do
           hp:=hp^.greater;
         case_get_max:=hp^._high;
      end;


    function case_get_min(root : pcaserecord) : longint;
      var
         hp : pcaserecord;
      begin
         hp:=root;
         while assigned(hp^.less) do
           hp:=hp^.less;
         case_get_min:=hp^._low;
      end;

end.
{
  $Log$
  Revision 1.101  1999-11-06 14:34:31  peter
    * truncated log to 20 revs

  Revision 1.100  1999/10/22 14:37:31  peter
    * error when properties are passed to var parameters

  Revision 1.99  1999/09/27 23:45:03  peter
    * procinfo is now a pointer
    * support for result setting in sub procedure

  Revision 1.98  1999/09/26 21:30:22  peter
    + constant pointer support which can happend with typecasting like
      const p=pointer(1)
    * better procvar parsing in typed consts

  Revision 1.97  1999/09/17 17:14:13  peter
    * @procvar fixes for tp mode
    * @<id>:= gives now an error

  Revision 1.96  1999/09/16 11:34:59  pierre
   * typo correction

  Revision 1.95  1999/09/10 18:48:11  florian
    * some bug fixes (e.g. must_be_valid and procinfo^.funcret_is_valid)
    * most things for stored properties fixed

  Revision 1.94  1999/09/07 07:52:20  peter
    * > < >= <= support for boolean
    * boolean constants are now calculated like integer constants

  Revision 1.93  1999/08/27 10:38:31  pierre
   + EXTTEMPREGDEBUG code added

  Revision 1.92  1999/08/26 21:10:08  peter
    * better error recovery for case

  Revision 1.91  1999/08/23 23:26:00  pierre
    + TEMPREGDEBUG code, test of register allocation
      if a tree uses more than registers32 regs then
      internalerror(10) is issued
    + EXTTEMPREGDEBUG will also give internalerror(10) if
      a same register is freed twice (happens in several part
      of current compiler like addn for strings and sets)

  Revision 1.90  1999/08/17 13:26:09  peter
    * arrayconstructor -> arrayofconst fixed when arraycosntructor was not
      variant.

  Revision 1.89  1999/08/16 23:23:42  peter
    * arrayconstructor -> openarray type conversions for element types

  Revision 1.88  1999/08/13 21:33:18  peter
    * support for array constructors extended and more error checking

  Revision 1.87  1999/08/09 22:14:46  peter
    * fixed disposing of tree node

  Revision 1.86  1999/08/04 00:23:49  florian
    * renamed i386asm and i386base to cpuasm and cpubase

  Revision 1.85  1999/08/03 22:03:40  peter
    * moved bitmask constants to sets
    * some other type/const renamings

  Revision 1.84  1999/07/27 23:42:24  peter
    * indirect type referencing is now allowed

  Revision 1.83  1999/05/27 19:45:29  peter
    * removed oldasm
    * plabel -> pasmlabel
    * -a switches to source writing automaticly
    * assembler readers OOPed
    * asmsymbol automaticly external
    * jumptables and other label fixes for asm readers

  Revision 1.82  1999/05/18 14:15:59  peter
    * containsself fixes
    * checktypes()

  Revision 1.81  1999/05/18 09:52:22  peter
    * procedure of object and addrn fixes

}