fpc/compiler/jvmdef.pas

{
    Copyright (c) 2010 by Jonas Maebe

    This unit implements some JVM type helper routines (minimal
    unit dependencies, usable in symdef).

    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.

 ****************************************************************************
}

{$i fpcdefs.inc}

unit jvmdef;

interface

    uses
      node,
      symtype;

    { Encode a type into the internal format used by the JVM (descriptor).
      Returns false if a type is not representable by the JVM,
      and in that case also the failing definition.  }
    function jvmtryencodetype(def: tdef; out encodedtype: ansistring; out founderror: tdef): boolean;

    { Check whether a type can be used in a JVM methom signature or field
      declaration.  }
    function jvmchecktype(def: tdef; out founderror: tdef): boolean;

    function jvmaddencodedtype(def: tdef; bpacked: boolean; var encodedstr: ansistring; out founderror: tdef): boolean;

implementation

  uses
    globtype,
    cutils,cclasses,
    verbose,systems,
    symtable,symconst,symsym,symdef,
    defutil,paramgr;

{******************************************************************
                          Type encoding
*******************************************************************}

    function jvmaddencodedtype(def: tdef; bpacked: boolean; var encodedstr: ansistring; out founderror: tdef): boolean;
      var
        recname: ansistring;
        recdef: trecorddef;
        objdef: tobjectdef;
        len: aint;
        c: char;
        addrpara: boolean;
      begin
        result:=true;
        case def.typ of
          stringdef :
            begin
              case tstringdef(def).stringtype of
                { translated into Java.Lang.String }
                st_widestring:
                  encodedstr:=encodedstr+'Ljava/lang/String;';
                else
                  { May be handled via wrapping later  }
                  result:=false;
              end;
            end;
          enumdef,
          orddef :
            begin
              { for procedure "results" }
              if is_void(def) then
                c:='V'
              { only Pascal-style booleans conform to Java's definition of
                Boolean }
              else if is_pasbool(def) and
                      (def.size=1) then
                c:='Z'
              else if is_widechar(def) then
                c:='C'
              else
                begin
                  case def.size of
                    1:
                      c:='B';
                    2:
                      c:='S';
                    4:
                      c:='I';
                    8:
                      c:='J';
                    else
                      internalerror(2010121905);
                  end;
                end;
              encodedstr:=encodedstr+c;
            end;
          pointerdef :
            begin
              { some may be handled via wrapping later }
              result:=false;
            end;
          floatdef :
            begin
              case tfloatdef(def).floattype of
                s32real:
                  c:='F';
                s64real:
                  c:='D';
                else
                  result:=false;
              end;
              encodedstr:=encodedstr+c;
            end;
          filedef :
            result:=false;
          recorddef :
            begin
              { will be hanlded via wrapping later, although wrapping may
                happen at higher level }
              result:=false;
            end;
          variantdef :
            begin
              { will be hanlded via wrapping later, although wrapping may
                happen at higher level }
              result:=false;
            end;
          classrefdef :
            begin
              { may be handled via wrapping later }
              result:=false;
            end;
          setdef :
            begin
              { will be hanlded via wrapping later, although wrapping may
                happen at higher level }
              result:=false;
            end;
          formaldef :
            begin
              { not supported (may be changed into "java.lang.Object" later) }
              result:=false;
            end;
          arraydef :
            begin
              if is_array_of_const(def) or
                 is_open_array(def) or
                 is_packed_array(def) then
                result:=false
              else
                begin
                  encodedstr:=encodedstr+'[';
                  if not jvmaddencodedtype(tarraydef(def).elementdef,false,encodedstr,founderror) then
                    begin
                      result:=false;
                      { report the exact (nested) error defintion }
                      exit;
                    end;
                end;
            end;
          procvardef :
            begin
              { will be hanlded via wrapping later, although wrapping may
                happen at higher level }
              result:=false;
            end;
          objectdef :
            case tobjectdef(def).objecttype of
              odt_javaclass,
              odt_interfacejava:
                encodedstr:=encodedstr+'L'+tobjectdef(def).objextname^+';';
              else
                result:=false;
            end;
          undefineddef,
          errordef :
            result:=false;
          procdef :
            { must be done via jvmencodemethod() }
            internalerror(2010121903);
        else
          internalerror(2010121904);
        end;
        if not result then
          founderror:=def;
      end;


    function jvmtryencodetype(def: tdef; out encodedtype: ansistring; out founderror: tdef): boolean;
      begin
        result:=jvmaddencodedtype(def,false,encodedtype,founderror);
      end;


{******************************************************************
                    jvm type validity checking
*******************************************************************}

   function jvmchecktype(def: tdef; out founderror: tdef): boolean;
      var
        encodedtype: ansistring;
      begin
        { don't duplicate the code like in objcdef, since the resulting strings
          are much shorter here so it's not worth it }
        result:=jvmtryencodetype(def,encodedtype,founderror);
      end;


end.