freepascal.compiler/compiler/pkgutil.pas

{
    Copyright (c) 2013-2016 by Free Pascal Development Team

    This unit implements basic parts of the package system

    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 pkgutil;

{$i fpcdefs.inc}

interface

  uses
    fmodule,fpkg,link,cstreams,cclasses;

  procedure createimportlibfromexternals;
  Function RewritePPU(const PPUFn:String;OutStream:TCStream):Boolean;
  procedure export_unit(u:tmodule);
  procedure load_packages;
  procedure add_package(const name:string;ignoreduplicates:boolean;direct:boolean);
  procedure add_package_unit_ref(package:tpackage);
  procedure add_package_libs(l:tlinker);
  procedure check_for_indirect_package_usages(modules:tlinkedlist);

implementation

  uses
    sysutils,
    globtype,systems,
    cutils,
    globals,verbose,
    aasmbase,aasmdata,aasmcnst,
    symtype,symconst,symsym,symdef,symbase,symtable,
    psub,pdecsub,
    ncgutil,
    ppu,entfile,fpcp,
    export;

  procedure procexport(const s : string);
    var
      hp : texported_item;
    begin
      hp:=texported_item.create;
      hp.name:=stringdup(s);
      hp.options:=hp.options+[eo_name];
      exportlib.exportprocedure(hp);
    end;


  procedure varexport(const s : string);
    var
      hp : texported_item;
    begin
      hp:=texported_item.create;
      hp.name:=stringdup(s);
      hp.options:=hp.options+[eo_name];
      exportlib.exportvar(hp);
    end;


  procedure exportprocsym(sym:tprocsym;symtable:tsymtable);
    var
      i : longint;
      item : TCmdStrListItem;
      pd : tprocdef;
    begin
      for i:=0 to tprocsym(sym).ProcdefList.Count-1 do
        begin
          pd:=tprocdef(tprocsym(sym).procdeflist[i]);
          if not(pd.proccalloption in [pocall_internproc]) and
              ((pd.procoptions*[po_external])=[]) and
              (
                (symtable.symtabletype in [globalsymtable,recordsymtable,objectsymtable]) or
                (
                  (symtable.symtabletype=staticsymtable) and
                  ([po_public,po_has_public_name]*pd.procoptions<>[])
                )
              ) then
            begin
              exportallprocdefnames(tprocsym(sym),pd,[eo_name,eo_no_sym_name]);
            end;
        end;
    end;


  procedure exportabstractrecorddef(def:tabstractrecorddef;symtable:tsymtable); forward;


  procedure exportabstractrecordsymproc(sym:tobject;arg:pointer);
    var
      def : tabstractrecorddef;
    begin
      case tsym(sym).typ of
        typesym:
          begin
            case ttypesym(sym).typedef.typ of
              objectdef,
              recorddef:
                exportabstractrecorddef(tabstractrecorddef(ttypesym(sym).typedef),tsymtable(arg));
            end;
          end;
        procsym:
          begin
            { don't export methods of interfaces }
            if is_interface(tdef(tabstractrecordsymtable(arg).defowner)) then
              exit;
            exportprocsym(tprocsym(sym),tsymtable(arg));
          end;
        staticvarsym:
          begin
            varexport(tsym(sym).mangledname);
          end;
      end;
    end;


  procedure exportname(const s:tsymstr);
    var
      hp : texported_item;
    begin
      hp:=texported_item.create;
      hp.name:=stringdup(s);
      hp.options:=hp.options+[eo_name];
      exportlib.exportvar(hp);
    end;


  procedure exportabstractrecorddef(def:tabstractrecorddef;symtable:tsymtable);
    var
      hp : texported_item;
    begin
      { for cross unit type aliases this might happen }
      if def.owner<>symtable then
        exit;
      { don't export generics or their nested types }
      if df_generic in def.defoptions then
        exit;
      def.symtable.SymList.ForEachCall(@exportabstractrecordsymproc,def.symtable);
      if def.typ=objectdef then
        begin
          if (oo_has_vmt in tobjectdef(def).objectoptions) then
            exportname(tobjectdef(def).vmt_mangledname);
          if is_interface(def) then
            begin
              if assigned(tobjectdef(def).iidguid) then
                exportname(make_mangledname('IID',def.owner,def.objname^));
              exportname(make_mangledname('IIDSTR',def.owner,def.objname^));
            end;
        end;
    end;


  procedure export_typedef(def:tdef;symtable:tsymtable;global:boolean);
    begin
      if not (global or is_class(def)) or
          (df_internal in def.defoptions) or
          { happens with type renaming declarations ("abc = xyz") }
          (def.owner<>symtable) then
        exit;
      if ds_rtti_table_written in def.defstates then
        exportname(def.rtti_mangledname(fullrtti));
      if (ds_init_table_written in def.defstates) and
          def.needs_separate_initrtti then
        exportname(def.rtti_mangledname(initrtti));
      case def.typ of
        recorddef,
        objectdef:
          exportabstractrecorddef(tabstractrecorddef(def),symtable);
      end;
    end;


  procedure insert_export(sym : TObject;arg:pointer);
    var
      i : longint;
      item : TCmdStrListItem;
      isglobal,
      publiconly : boolean;
    begin
      publiconly:=tsymtable(arg).symtabletype=staticsymtable;
      isglobal:=tsymtable(arg).symtabletype=globalsymtable;
      case TSym(sym).typ of
        { ignore: }
        unitsym,
        syssym,
        namespacesym,
        propertysym,
        enumsym:
          ;
        constsym:
          begin
            if tconstsym(sym).consttyp=constresourcestring then
              varexport(make_mangledname('RESSTR',tsym(sym).owner,tsym(sym).name));
          end;
        typesym:
          begin
            export_typedef(ttypesym(sym).typedef,tsymtable(arg),isglobal);
          end;
        procsym:
          begin
            exportprocsym(tprocsym(sym),tsymtable(arg));
          end;
        staticvarsym:
          begin
            if publiconly and not (vo_is_public in tstaticvarsym(sym).varoptions) then
              exit;
            varexport(tsym(sym).mangledname);
          end;
        absolutevarsym:
          ;
        else
          begin
            //writeln('unknown: ',TSym(sym).typ);
            internalerror(2016080501);
          end;
      end;
    end;


  procedure export_unit(u: tmodule);
    var
      i : longint;
      sym : tasmsymbol;
    begin
      u.globalsymtable.symlist.ForEachCall(@insert_export,u.globalsymtable);
      { check localsymtable for exports too to get public symbols }
      u.localsymtable.symlist.ForEachCall(@insert_export,u.localsymtable);

      { create special exports }
      if (u.flags and uf_init)<>0 then
        procexport(make_mangledname('INIT$',u.globalsymtable,''));
      if (u.flags and uf_finalize)<>0 then
        procexport(make_mangledname('FINALIZE$',u.globalsymtable,''));
      if (u.flags and uf_threadvars)=uf_threadvars then
        varexport(make_mangledname('THREADVARLIST',u.globalsymtable,''));
      if (u.flags and uf_has_resourcestrings)<>0 then
        begin
          varexport(ctai_typedconstbuilder.get_vectorized_dead_strip_section_symbol_start('RESSTR',u.localsymtable,[]).name);
          varexport(ctai_typedconstbuilder.get_vectorized_dead_strip_section_symbol_end('RESSTR',u.localsymtable,[]).name);
        end;

      if not (target_info.system in systems_indirect_var_imports) then
        for i:=0 to u.publicasmsyms.count-1 do
          begin
            sym:=tasmsymbol(u.publicasmsyms[i]);
            if sym.bind=AB_INDIRECT then
              varexport(sym.name);
          end;
    end;

  Function RewritePPU(const PPUFn:String;OutStream:TCStream):Boolean;
    Var
      MakeStatic : Boolean;
    Var
      buffer : array[0..$1fff] of byte;
      inppu,
      outppu : tppufile;
      b,
      untilb : byte;
      l,m    : longint;
      f      : file;
      ext,
      s      : string;
      ppuversion : dword;
    begin
      Result:=false;
      MakeStatic:=False;
      inppu:=tppufile.create(PPUFn);
      if not inppu.openfile then
       begin
         inppu.free;
         Comment(V_Error,'Could not open : '+PPUFn);
         Exit;
       end;
    { Check the ppufile }
      if not inppu.CheckPPUId then
       begin
         inppu.free;
         Comment(V_Error,'Not a PPU File : '+PPUFn);
         Exit;
       end;
      ppuversion:=inppu.getversion;
      if ppuversion<CurrentPPUVersion then
       begin
         inppu.free;
         Comment(V_Error,'Wrong PPU Version '+tostr(ppuversion)+' in '+PPUFn);
         Exit;
       end;
    { Already a lib? }
      if (inppu.header.common.flags and uf_in_library)<>0 then
       begin
         inppu.free;
         Comment(V_Error,'PPU is already in a library : '+PPUFn);
         Exit;
       end;
    { We need a static linked unit, but we also accept those without .o file }
      if (inppu.header.common.flags and (uf_static_linked or uf_no_link))=0 then
       begin
         inppu.free;
         Comment(V_Error,'PPU is not static linked : '+PPUFn);
         Exit;
       end;
    { Check if shared is allowed }
      if tsystem(inppu.header.common.target) in [system_i386_go32v2] then
       begin
         Comment(V_Error,'Shared library not supported for ppu target, switching to static library');
         MakeStatic:=true;
       end;
    { Create the new ppu }
      outppu:=tppufile.create(PPUFn);
      outppu.createstream(OutStream);
    { Create new header, with the new flags }
      outppu.header:=inppu.header;
      outppu.header.common.flags:=outppu.header.common.flags or uf_in_library;
      if MakeStatic then
       outppu.header.common.flags:=outppu.header.common.flags or uf_static_linked
      else
       outppu.header.common.flags:=outppu.header.common.flags or uf_shared_linked;
    { read until the object files are found }
      untilb:=iblinkunitofiles;
      repeat
        b:=inppu.readentry;
        if b in [ibendinterface,ibend] then
         begin
           inppu.free;
           outppu.free;
           Comment(V_Error,'No files to be linked found : '+PPUFn);
           Exit;
         end;
        if b<>untilb then
         begin
           repeat
             inppu.getdatabuf(buffer,sizeof(buffer),l);
             outppu.putdata(buffer,l);
           until l<sizeof(buffer);
           outppu.writeentry(b);
         end;
      until (b=untilb);
    { we have now reached the section for the files which need to be added,
      now add them to the list }
      case b of
        iblinkunitofiles :
          begin
            { add all o files, and save the entry when not creating a static
              library to keep staticlinking possible }
            while not inppu.endofentry do
             begin
               s:=inppu.getstring;
               m:=inppu.getlongint;
               if not MakeStatic then
                begin
                  outppu.putstring(s);
                  outppu.putlongint(m);
                end;
               current_module.linkotherofiles.add(s,link_always);;
             end;
            if not MakeStatic then
             outppu.writeentry(b);
          end;
    {    iblinkunitstaticlibs :
          begin
            AddToLinkFiles(ExtractLib(inppu.getstring));
            if not inppu.endofentry then
             begin
               repeat
                 inppu.getdatabuf(buffer^,bufsize,l);
                 outppu.putdata(buffer^,l);
               until l<bufsize;
               outppu.writeentry(b);
             end;
           end; }
      end;
    { just add a new entry with the new lib }
      if MakeStatic then
       begin
         outppu.putstring('imp'+current_module.realmodulename^);
         outppu.putlongint(link_static);
         outppu.writeentry(iblinkunitstaticlibs)
       end
      else
       begin
         outppu.putstring('imp'+current_module.realmodulename^);
         outppu.putlongint(link_shared);
         outppu.writeentry(iblinkunitsharedlibs);
       end;
    { read all entries until the end and write them also to the new ppu }
      repeat
        b:=inppu.readentry;
      { don't write ibend, that's written automatically }
        if b<>ibend then
         begin
           if b=iblinkothersharedlibs then
             begin
               while not inppu.endofentry do
                 begin
                   s:=inppu.getstring;
                   m:=inppu.getlongint;

                   outppu.putstring(s);
                   outppu.putlongint(m);

                   { strip lib prefix }
                   if copy(s,1,3)='lib' then
                     delete(s,1,3);
                   ext:=ExtractFileExt(s);
                   if ext<>'' then
                     delete(s,length(s)-length(ext)+1,length(ext));

                   current_module.linkOtherSharedLibs.add(s,link_always);
                 end;
             end
           else
             repeat
               inppu.getdatabuf(buffer,sizeof(buffer),l);
               outppu.putdata(buffer,l);
             until l<sizeof(buffer);
           outppu.writeentry(b);
         end;
      until b=ibend;
    { write the last stuff and close }
      outppu.flush;
      outppu.writeheader;
      outppu.free;
      inppu.free;
      Result:=True;
    end;


  procedure load_packages;
    var
      i,j : longint;
      pcp: tpcppackage;
      entry,
      entryreq : ppackageentry;
      name,
      uname : string;
    begin
      if not (tf_supports_packages in target_info.flags) then
        exit;
      i:=0;
      while i<packagelist.count do
        begin
          entry:=ppackageentry(packagelist[i]);
          if assigned(entry^.package) then
            internalerror(2013053104);
          Comment(V_Info,'Loading package: '+entry^.realpkgname);
          pcp:=tpcppackage.create(entry^.realpkgname);
          pcp.loadpcp;
          entry^.package:=pcp;

          { add all required packages that are not yet part of packagelist }
          for j:=0 to pcp.requiredpackages.count-1 do
            begin
              name:=pcp.requiredpackages.NameOfIndex(j);
              uname:=upper(name);
              if not assigned(packagelist.Find(uname)) then
                begin
                  New(entryreq);
                  entryreq^.realpkgname:=name;
                  entryreq^.package:=nil;
                  entryreq^.usedunits:=0;
                  entryreq^.direct:=false;
                  packagelist.add(uname,entryreq);
                end;
            end;

          Inc(i);
        end;

      { all packages are now loaded, so we can fill in the links of the required packages }
      for i:=0 to packagelist.count-1 do
        begin
          entry:=ppackageentry(packagelist[i]);
          if not assigned(entry^.package) then
            internalerror(2015111301);
          for j:=0 to entry^.package.requiredpackages.count-1 do
            begin
              if assigned(entry^.package.requiredpackages[j]) then
                internalerror(2015111303);
              entryreq:=packagelist.find(upper(entry^.package.requiredpackages.NameOfIndex(j)));
              if not assigned(entryreq) then
                internalerror(2015111302);
              entry^.package.requiredpackages[j]:=entryreq^.package;
            end;
        end;
    end;


  procedure add_package(const name:string;ignoreduplicates:boolean;direct:boolean);
    var
      entry : ppackageentry;
      i : longint;
    begin
      for i:=0 to packagelist.count-1 do
        begin
          if packagelist.nameofindex(i)=name then
            begin
              if not ignoreduplicates then
                Message1(package_e_duplicate_package,name);
              exit;
            end;
        end;
      new(entry);
      entry^.package:=nil;
      entry^.realpkgname:=name;
      entry^.usedunits:=0;
      entry^.direct:=direct;
      packagelist.add(upper(name),entry);
    end;


  procedure add_package_unit_ref(package: tpackage);
    var
      pkgentry : ppackageentry;
    begin
      pkgentry:=ppackageentry(packagelist.find(package.packagename^));
      if not assigned(pkgentry) then
        internalerror(2015100301);
      inc(pkgentry^.usedunits);
    end;


  procedure add_package_libs(l:tlinker);
    var
      pkgentry : ppackageentry;
      i : longint;
      pkgname : tpathstr;
    begin
      if target_info.system in systems_indirect_var_imports then
        { we're using import libraries anyway }
        exit;
      for i:=0 to packagelist.count-1 do
        begin
          pkgentry:=ppackageentry(packagelist[i]);
          if pkgentry^.usedunits>0 then
            begin
              //writeln('package used: ',pkgentry^.realpkgname);
              pkgname:=pkgentry^.package.pplfilename;
              if copy(pkgname,1,length(target_info.sharedlibprefix))=target_info.sharedlibprefix then
                delete(pkgname,1,length(target_info.sharedlibprefix));
              if copy(pkgname,length(pkgname)-length(target_info.sharedlibext)+1,length(target_info.sharedlibext))=target_info.sharedlibext then
                delete(pkgname,length(pkgname)-length(target_info.sharedlibext)+1,length(target_info.sharedlibext));
              //writeln('adding library: ', pkgname);
              l.sharedlibfiles.concat(pkgname);
            end
          else
            {writeln('ignoring package: ',pkgentry^.realpkgname)};
        end;
    end;


  procedure check_for_indirect_package_usages(modules:tlinkedlist);
    var
      uu : tused_unit;
      pentry : ppackageentry;
    begin
      uu:=tused_unit(modules.first);
      while assigned(uu) do
        begin
          if assigned(uu.u.package) then
            begin
              pentry:=ppackageentry(packagelist.find(uu.u.package.packagename^));
              if not assigned(pentry) then
                internalerror(2015112304);
              if not pentry^.direct then
                Message2(package_w_unit_from_indirect_package,uu.u.realmodulename^,uu.u.package.realpackagename^);
            end;

          uu:=tused_unit(uu.Next);
        end;
    end;


  procedure createimportlibfromexternals;
    type
      tcacheentry=record
        pkg:tpackage;
        sym:tasmsymbol;
      end;
      pcacheentry=^tcacheentry;
    var
      cache : tfphashlist;
      alreadyloaded : tfpobjectlist;


      function findpackagewithsym(symname:tsymstr):tcacheentry;
        var
          i,j : longint;
          pkgentry : ppackageentry;
          unitentry : pcontainedunit;
        begin
          for i:=0 to packagelist.count-1 do
            begin
              pkgentry:=ppackageentry(packagelist[i]);
              for j:=0 to pkgentry^.package.containedmodules.count-1 do
                begin
                  unitentry:=pcontainedunit(pkgentry^.package.containedmodules[j]);
                  if not assigned(unitentry^.module) then
                    { the unit is not loaded }
                    continue;
                  result.sym:=tasmsymbol(tmodule(unitentry^.module).publicasmsyms.find(symname));
                  if assigned(result.sym) then
                    begin
                      { completely ignore other external symbols }
                      if result.sym.bind in [ab_external,ab_weak_external] then
                        begin
                          result.sym:=nil;
                          continue;
                        end;
                      { only accept global symbols of the used unit }
                      if result.sym.bind<>ab_global then
                        begin
                          result.sym:=nil;
                          result.pkg:=nil;
                        end
                      else
                        result.pkg:=pkgentry^.package;
                      exit;
                    end;
                end;
            end;
          result.sym:=nil;
          result.pkg:=nil;
        end;


    procedure processasmsyms(symlist:tfphashobjectlist);
      var
        i,j,k : longint;
        sym : tasmsymbol;
        cacheentry : pcacheentry;
        list : TAsmList;
        labind : tasmsymbol;
        psym : tsymentry;
        pd : tprocdef;
        found : boolean;
        impname,symname : TSymStr;
        suffixidx : longint;
      begin
        for i:=0 to symlist.count-1 do
          begin
            sym:=tasmsymbol(symlist[i]);
            if not (sym.bind in [ab_external,ab_external_indirect]) then
              continue;

            { remove the indirect suffix }
            symname:=sym.name;
            if sym.bind=ab_external_indirect then
              begin
                suffixidx:=pos(suffix_indirect,symname);
                if suffixidx=length(symname)-length(suffix_indirect)+1 then
                  symname:=copy(symname,1,suffixidx-1)
                else
                  internalerror(2016062401);
              end;

            { did we already import the symbol? }
            cacheentry:=pcacheentry(cache.find(symname));
            if assigned(cacheentry) then
              continue;

            { was the symbol already imported in the previous pass? }
            found:=false;
            for j:=0 to alreadyloaded.count-1 do
              begin
                psym:=tsymentry(alreadyloaded[j]);
                case psym.typ of
                  procsym:
                    for k:=0 to tprocsym(psym).procdeflist.count-1 do
                      begin
                        pd:=tprocdef(tprocsym(psym).procdeflist[k]);
                        if has_alias_name(pd,symname) or
                            (
                              ([po_external,po_has_importdll]*pd.procoptions=[po_external,po_has_importdll]) and
                              (symname=proc_get_importname(pd))
                            ) then
                          begin
                            found:=true;
                            break;
                          end;
                      end;
                  staticvarsym:
                    if tstaticvarsym(psym).mangledname=symname then
                      found:=true;
                  constsym:
                    begin
                      if tconstsym(psym).consttyp<>constresourcestring then
                        internalerror(2016072202);
                      if make_mangledname('RESSTR',psym.owner,psym.name)=symname then
                        found:=true;
                    end;
                  else
                    internalerror(2014101003);
                end;
                if found then
                  break;
              end;
            if found then begin
              { add a dummy entry }
              new(cacheentry);
              cacheentry^.pkg:=nil;
              cacheentry^.sym:=sym;
              cache.add(symname,cacheentry);
              continue;
            end;

            new(cacheentry);
            cacheentry^:=findpackagewithsym(symname);
            cache.add(symname,cacheentry);

            { use cacheentry^.sym instead of sym, because for the later typ
              is always at_none in case of an external symbol }
            if assigned(cacheentry^.pkg) then
              begin
                impname:=symname;
                if cacheentry^.sym.typ=AT_DATA then
                  { import as the $indirect symbol if it as a variable }
                  impname:=symname+suffix_indirect;
                current_module.addexternalimport(cacheentry^.pkg.pplfilename,symname,impname,0,cacheentry^.sym.typ=at_data,false);
              end;
          end;
      end;


    procedure import_proc_symbol(pd:tprocdef;pkg:tpackage);
      var
        item : TCmdStrListItem;
      begin
        item := TCmdStrListItem(pd.aliasnames.first);
        if not assigned(item) then
          { at least import the mangled name }
          current_module.addexternalimport(pkg.pplfilename,pd.mangledname,pd.mangledname,0,false,false);
        while assigned(item) do
          begin
            current_module.addexternalimport(pkg.pplfilename,item.str,item.str,0,false,false);
            item := TCmdStrListItem(item.next);
          end;
       end;


    procedure processimportedsyms(syms:tfpobjectlist);
      var
        i,j,k,l : longint;
        pkgentry : ppackageentry;
        sym : TSymEntry;
        srsymtable : tsymtable;
        module : tmodule;
        unitentry : pcontainedunit;
        name : tsymstr;
        pd : tprocdef;
      begin
        for i:=0 to syms.count-1 do
          begin
            sym:=tsymentry(syms[i]);
            if not (sym.typ in [staticvarsym,procsym,constsym]) or
                (
                  (sym.typ=constsym) and
                  (tconstsym(sym).consttyp<>constresourcestring)
                ) then
              continue;
            if alreadyloaded.indexof(sym)>=0 then
              continue;
            { determine the unit of the symbol }
            srsymtable:=sym.owner;
            while not (srsymtable.symtabletype in [staticsymtable,globalsymtable]) do
              srsymtable:=srsymtable.defowner.owner;
            module:=tmodule(loaded_units.first);
            while assigned(module) do
              begin
                if (module.globalsymtable=srsymtable) or (module.localsymtable=srsymtable) then
                  break;
                module:=tmodule(module.next);
              end;
            if not assigned(module) then
              internalerror(2014101001);
            if (uf_in_library and module.flags)=0 then
              { unit is not part of a package, so no need to handle it }
              continue;
            { loaded by a package? }
            for j:=0 to packagelist.count-1 do
              begin
                pkgentry:=ppackageentry(packagelist[j]);
                for k:=0 to pkgentry^.package.containedmodules.count-1 do
                  begin
                    unitentry:=pcontainedunit(pkgentry^.package.containedmodules[k]);
                    if unitentry^.module=module then
                      begin
                        case sym.typ of
                          constsym:
                            begin
                              if tconstsym(sym).consttyp<>constresourcestring then
                                internalerror(2016072201);
                              name:=make_mangledname('RESSTR',sym.owner,sym.name);
                              current_module.addexternalimport(pkgentry^.package.pplfilename,name,name+suffix_indirect,0,true,false);
                            end;
                          staticvarsym:
                            begin
                              name:=tstaticvarsym(sym).mangledname;
                              current_module.addexternalimport(pkgentry^.package.pplfilename,name,name+suffix_indirect,0,true,false);
                            end;
                          procsym:
                            begin
                              for l:=0 to tprocsym(sym).procdeflist.count-1 do
                                begin
                                  pd:=tprocdef(tprocsym(sym).procdeflist[l]);
                                  if [po_external,po_has_importdll]*pd.procoptions=[po_external,po_has_importdll] then
                                    { if we use an external procedure of another unit we
                                      need to import it ourselves from the correct library }
                                    import_external_proc(pd)
                                  else
                                    import_proc_symbol(pd,pkgentry^.package);
                                end;
                            end;
                          else
                            internalerror(2014101002);
                        end;
                        alreadyloaded.add(sym);
                      end;
                  end;
              end;
          end;
      end;


    var
      unitentry : pcontainedunit;
      module : tmodule;
      i : longint;
    begin
      cache:=tfphashlist.create;
      { check each external asm symbol of each unit of the package whether it is
        contained in the unit of a loaded package (and thus an import entry
        is needed) }
      alreadyloaded:=tfpobjectlist.create(false);

      { first pass to find all symbols that were not loaded by asm name }
      module:=tmodule(loaded_units.first);
      while assigned(module) do
        begin
          if not assigned(module.package) then
            processimportedsyms(module.unitimportsyms);
          module:=tmodule(module.next);
        end;

      { second pass to find all symbols that were loaded by asm name }
      module:=tmodule(loaded_units.first);
      while assigned(module) do
        begin
          if not assigned(module.package) then
            processasmsyms(module.externasmsyms);
          module:=tmodule(module.next);
        end;

      alreadyloaded.free;
      for i:=0 to cache.count-1 do
        dispose(pcacheentry(cache[i]));
      cache.free;
    end;


end.