freepascal.compiler/compiler/llvm/agllvm.pas

{
    Copyright (c) 1998-2013 by the Free Pascal team

    This unit implements the generic part of the LLVM IR writer

    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 agllvm;

{$i fpcdefs.inc}

interface

    uses
      globtype,globals,
      aasmbase,aasmtai,aasmdata,
      assemble;

    type
      TLLVMInstrWriter = class;
      { TLLVMAssember }

      TLLVMAssember=class(texternalassembler)
      protected
        fdecllevel: longint;

        procedure WriteExtraHeader;virtual;
        procedure WriteExtraFooter;virtual;
        procedure WriteInstruction(hp: tai);
        procedure WriteLlvmInstruction(hp: tai);
//        procedure WriteWeakSymbolDef(s: tasmsymbol); virtual;
        procedure WriteDirectiveName(dir: TAsmDirective); virtual;
        procedure WriteWeakSymbolDef(s: tasmsymbol);
        procedure WriteRealConst(hp: tai_realconst; do_line: boolean);
        procedure WriteOrdConst(hp: tai_const);
        procedure WriteTai(const replaceforbidden: boolean; const do_line: boolean; var InlineLevel: cardinal; var hp: tai);
       public
        constructor create(smart: boolean); override;
        procedure AsmLn; override;
        function MakeCmdLine: TCmdStr; override;
        procedure WriteTree(p:TAsmList);override;
        procedure WriteAsmList;override;
        destructor destroy; override;
       protected
        InstrWriter: TLLVMInstrWriter;
      end;


      {# This is the base class for writing instructions.

         The WriteInstruction() method must be overridden
         to write a single instruction to the assembler
         file.
      }
      TLLVMInstrWriter = class
        constructor create(_owner: TLLVMAssember);
        procedure WriteInstruction(hp : tai);
       protected
        owner: TLLVMAssember;

        function InstructionToString(hp : tai): TSymStr;
        function getopstr(const o:toper; refwithalign: boolean) : TSymStr;
      end;


implementation

    uses
      SysUtils,
      cutils,cfileutl,systems,
      fmodule,verbose,
      symconst,symdef,
      llvmbase,aasmllvm,itllvm,llvmdef,
      cgbase,cgutils,cpubase;

    const
      line_length = 70;

    var
      symendcount  : longint;

    type
{$ifdef cpuextended}
      t80bitarray = array[0..9] of byte;
{$endif cpuextended}
      t64bitarray = array[0..7] of byte;
      t32bitarray = array[0..3] of byte;

{****************************************************************************}
{                          Support routines                                  }
{****************************************************************************}

    function single2str(d : single) : string;
      var
         hs : string;
      begin
         str(d,hs);
      { replace space with + }
         if hs[1]=' ' then
          hs[1]:='+';
         single2str:=hs
      end;

    function double2str(d : double) : string;
      var
         hs : string;
      begin
         str(d,hs);
      { replace space with + }
         if hs[1]=' ' then
          hs[1]:='+';
         double2str:=hs
      end;

    function extended2str(e : extended) : string;
      var
         hs : string;
      begin
         str(e,hs);
      { replace space with + }
         if hs[1]=' ' then
          hs[1]:='+';
         extended2str:=hs
      end;


 {****************************************************************************}
 {                        LLVM Instruction writer                             }
 {****************************************************************************}

    function getregisterstring(reg: tregister): ansistring;
      begin
        if getregtype(reg)=R_TEMPREGISTER then
          result:='%tmp.'
        else
          result:='%reg.'+tostr(byte(getregtype(reg)))+'_';
        result:=result+tostr(getsupreg(reg));
      end;


    function getreferencealignstring(var ref: treference) : ansistring;
      begin
        result:=', align '+tostr(ref.alignment);
      end;


    function getreferencestring(var ref : treference; withalign: boolean) : ansistring;
      begin
        result:='';
        if assigned(ref.relsymbol) or
           (assigned(ref.symbol) =
            (ref.base<>NR_NO)) or
           (ref.index<>NR_NO) or
           (ref.offset<>0) then
          begin
            result:=' **(error ref: ';
            if assigned(ref.symbol) then
              result:=result+'sym='+ref.symbol.name+', ';
            if assigned(ref.relsymbol) then
              result:=result+'sym='+ref.relsymbol.name+', ';
            if ref.base=NR_NO then
              result:=result+'base=NR_NO, ';
            if ref.index<>NR_NO then
              result:=result+'index<>NR_NO, ';
            if ref.offset<>0 then
              result:=result+'offset='+tostr(ref.offset);
            result:=result+')**'
//            internalerror(2013060225);
          end;
         if ref.base<>NR_NO then
           result:=result+getregisterstring(ref.base)
         else
           result:=result+ref.symbol.name;
         if withalign then
           result:=result+getreferencealignstring(ref);
      end;


   function getparas(const o: toper): ansistring;
     var
       i: longint;
       para: pllvmcallpara;
     begin
       result:='(';
       for i:=0 to o.paras.count-1 do
         begin
           if i<>0 then
             result:=result+', ';
           para:=pllvmcallpara(o.paras[i]);
           result:=result+llvmencodetype(para^.def);
           if para^.valueext<>lve_none then
             result:=result+llvmvalueextension2str[para^.valueext];
           case para^.loc of
             LOC_REGISTER,
             LOC_FPUREGISTER,
             LOC_MMREGISTER:
               result:=result+' '+getregisterstring(para^.reg);
             else
               internalerror(2014010801);
           end;
         end;
       result:=result+')';
     end;


   function llvmdoubletostr(const d: double): TSymStr;
     type
       tdoubleval = record
         case byte of
           1: (d: double);
           2: (i: int64);
       end;
     begin
       { "When using the hexadecimal form, constants of types half,
         float, and double are represented using the 16-digit form shown
         above (which matches the IEEE754 representation for double)"

         And always in big endian form (sign bit leftmost)
       }
       result:='0x'+hexstr(tdoubleval(d).i,16);
     end;


{$if defined(cpuextended) and defined(FPC_HAS_TYPE_EXTENDED)}
    function llvmextendedtostr(const e: extended): TSymStr;
      var
        extendedval: record
          case byte of
            1: (e: extended);
            2: (r: packed record
      {$ifdef FPC_LITTLE_ENDIAN}
                  l: int64;
                  h: word;
      {$else FPC_LITTLE_ENDIAN}
                  h: int64;
                  l: word;
      {$endif FPC_LITTLE_ENDIAN}
                end;
               );
        end;
      begin
        extendedval.e:=e;
        { hex format is always big endian in llvm }
        result:='0xK'+hexstr(extendedval.r.h,sizeof(extendedval.r.h)*2)+
                      hexstr(extendedval.r.l,sizeof(extendedval.r.l)*2);
      end;

{$endif cpuextended}


   function TLLVMInstrWriter.getopstr(const o:toper; refwithalign: boolean) : TSymStr;
     var
       hs : ansistring;
     begin
       case o.typ of
         top_reg:
           getopstr:=getregisterstring(o.reg);
         top_const:
           getopstr:=tostr(int64(o.val));
         top_ref:
           if o.ref^.refaddr=addr_full then
             begin
               getopstr:='';
               if o.ref^.symbol.typ=AT_LABEL then
                 getopstr:='label %';
               hs:=o.ref^.symbol.name;
               if o.ref^.offset<>0 then
                 internalerror(2013060223);
               getopstr:=getopstr+hs;
             end
           else
             getopstr:=getreferencestring(o.ref^,refwithalign);
         top_def:
           begin
             getopstr:=llvmencodetype(o.def);
           end;
         top_cond:
           begin
             getopstr:=llvm_cond2str[o.cond];
           end;
         top_fpcond:
           begin
             getopstr:=llvm_fpcond2str[o.fpcond];
           end;
         top_single,
         top_double:
           begin
             { "When using the hexadecimal form, constants of types half,
               float, and double are represented using the 16-digit form shown
               above (which matches the IEEE754 representation for double)"

               And always in big endian form (sign bit leftmost)
             }
             if o.typ=top_double then
               result:=llvmdoubletostr(o.dval)
             else
               result:=llvmdoubletostr(o.sval)
           end;
         top_para:
           begin
             result:=getparas(o);
           end;
         top_tai:
           begin
             result:=InstructionToString(o.ai);
           end;
{$if defined(cpuextended) and defined(FPC_HAS_TYPE_EXTENDED)}
         top_extended80:
           begin
             result:=llvmextendedtostr(o.eval);
           end;
{$endif cpuextended}
         else
           internalerror(2013060227);
       end;
     end;


  procedure TLLVMInstrWriter.WriteInstruction(hp: tai);
    begin
      owner.AsmWriteLn(InstructionToString(hp));
    end;


  function TLLVMInstrWriter.InstructionToString(hp: tai): TSymStr;
    var
      op: tllvmop;
      s, sep: TSymStr;
      i, opstart: byte;
      done: boolean;
    begin
      op:=taillvm(hp).llvmopcode;
      s:=#9;
      sep:=' ';
      done:=false;
      opstart:=0;
      case op of
        la_ret, la_br, la_switch, la_indirectbr,
        la_invoke, la_resume,
        la_unreachable,
        la_store,
        la_fence,
        la_cmpxchg,
        la_atomicrmw:
          begin
            { instructions that never have a result }
          end;
        la_call:
          begin
            if taillvm(hp).oper[0]^.reg<>NR_NO then
              s:=s+getregisterstring(taillvm(hp).oper[0]^.reg)+' = ';
            sep:=' ';
            opstart:=1;
          end;
        la_alloca:
          begin
            s:=s+getreferencestring(taillvm(hp).oper[0]^.ref^,false)+' = ';
            sep:=' ';
            opstart:=1;
          end;
        la_trunc, la_zext, la_sext, la_fptrunc, la_fpext,
        la_fptoui, la_fptosi, la_uitofp, la_sitofp,
        la_ptrtoint, la_inttoptr,
        la_bitcast:
          begin
            { destination can be empty in case of nested constructs, or
              data initialisers }
            if (taillvm(hp).oper[0]^.typ<>top_reg) or
               (taillvm(hp).oper[0]^.reg<>NR_NO) then
              s:=s+getopstr(taillvm(hp).oper[0]^,false)+' = ';
            s:=s+llvm_op2str[op]+' '+
              getopstr(taillvm(hp).oper[1]^,false)+' '+
              getopstr(taillvm(hp).oper[2]^,false)+' to '+
              getopstr(taillvm(hp).oper[3]^,false);
            done:=true;
          end
        else
          begin
            s:=s+getopstr(taillvm(hp).oper[0]^,true)+' = ';
            sep:=' ';
            opstart:=1
          end;
      end;
      { process operands }
      if not done then
        begin
          s:=s+llvm_op2str[op];
          if taillvm(hp).ops<>0 then
            begin
              for i:=opstart to taillvm(hp).ops-1 do
                begin
                   s:=s+sep+getopstr(taillvm(hp).oper[i]^,op in [la_load,la_store]);
                   if (taillvm(hp).oper[i]^.typ in [top_def,top_cond,top_fpcond]) or
                      (op=la_call) then
                     sep :=' '
                   else
                     sep:=', ';
                end;
            end;
        end;
      if op=la_alloca then
        begin
          s:=s+getreferencealignstring(taillvm(hp).oper[0]^.ref^)
        end;
      result:=s;
    end;

{****************************************************************************}
{                          LLVM Assembler writer                              }
{****************************************************************************}

    destructor TLLVMAssember.Destroy;
      begin
        InstrWriter.free;
        inherited destroy;
      end;


    function TLLVMAssember.MakeCmdLine: TCmdStr;
      var
        optstr: TCmdStr;
      begin
        result := inherited MakeCmdLine;
        { standard optimization flags for llc -- todo: this needs to be split
          into a call to opt and one to llc }
        if cs_opt_level3 in current_settings.optimizerswitches then
          optstr:='-O3'
        else if cs_opt_level2 in current_settings.optimizerswitches then
          optstr:='-O2'
        else if cs_opt_level1 in current_settings.optimizerswitches then
          optstr:='-O1'
        else
          optstr:='-O0';
        { stack frame elimination }
        if not(cs_opt_stackframe in current_settings.optimizerswitches) then
          optstr:=optstr+' -disable-fp-elim';
        { fast math }
        if cs_opt_fastmath in current_settings.optimizerswitches then
          optstr:=optstr+' -enable-unsafe-fp-math -enable-fp-mad -fp-contract=fast';
        { smart linking }
        if cs_create_smart in current_settings.moduleswitches then
          optstr:=optstr+' -fdata-sections -fcode-sections';
        { pic }
        if cs_create_pic in current_settings.moduleswitches then
          optstr:=optstr+' -relocation-model=pic'
        else if not(target_info.system in systems_darwin) then
          optstr:=optstr+' -relocation-model=static'
        else
          optstr:=optstr+' -relocation-model=dynamic-no-pic';
        { our stack alignment is non-standard on some targets. The following
          parameter is however ignored on some targets by llvm, so it may not
          be enough }
        optstr:=optstr+' -stack-alignment='+tostr(target_info.stackalign*8);
        { force object output instead of textual assembler code }
        optstr:=optstr+' -filetype=obj';
        replace(result,'$OPT',optstr);
      end;


    procedure TLLVMAssember.WriteTree(p:TAsmList);
    var
      hp       : tai;
      InlineLevel : cardinal;
      do_line  : boolean;
      replaceforbidden: boolean;
    begin
      if not assigned(p) then
       exit;
      replaceforbidden:=target_asm.dollarsign<>'$';

      InlineLevel:=0;
      { lineinfo is only needed for al_procedures (PFV) }
      do_line:=(cs_asm_source in current_settings.globalswitches) or
               ((cs_lineinfo in current_settings.moduleswitches)
                 and (p=current_asmdata.asmlists[al_procedures]));
      hp:=tai(p.first);
      while assigned(hp) do
       begin
         prefetch(pointer(hp.next)^);
         if not(hp.typ in SkipLineInfo) then
          begin
            current_filepos:=tailineinfo(hp).fileinfo;
            { no line info for inlined code }
            if do_line and (inlinelevel=0) then
              WriteSourceLine(hp as tailineinfo);
          end;

         WriteTai(replaceforbidden, do_line, InlineLevel, hp);
         hp:=tai(hp.next);
       end;
    end;


    procedure TLLVMAssember.WriteExtraHeader;
      begin
        AsmWrite('target datalayout = "');
        AsmWrite(target_info.llvmdatalayout);
        AsmWriteln('"');
        AsmWrite('target triple = "');
        AsmWrite(llvm_target_name);
        AsmWriteln('"');
      end;


    procedure TLLVMAssember.WriteExtraFooter;
      begin
      end;


    procedure TLLVMAssember.WriteInstruction(hp: tai);
      begin

      end;


    procedure TLLVMAssember.WriteLlvmInstruction(hp: tai);
      begin
        InstrWriter.WriteInstruction(hp);
      end;


    procedure TLLVMAssember.WriteWeakSymbolDef(s: tasmsymbol);
      begin
        AsmWriteLn(#9'.weak '+s.name);
      end;


    procedure TLLVMAssember.WriteRealConst(hp: tai_realconst; do_line: boolean);
      var
        pdata: pbyte;
        index, step, swapmask, count: longint;
      begin
        if do_line and
           (fdecllevel=0) then
          begin
            case tai_realconst(hp).realtyp of
              aitrealconst_s32bit:
                AsmWriteLn(target_asm.comment+'value: '+single2str(tai_realconst(hp).value.s32val));
              aitrealconst_s64bit:
                AsmWriteLn(target_asm.comment+'value: '+double2str(tai_realconst(hp).value.s64val));
{$if defined(cpuextended) and defined(FPC_HAS_TYPE_EXTENDED)}
              { can't write full 80 bit floating point constants yet on non-x86 }
              aitrealconst_s80bit:
                AsmWriteLn(target_asm.comment+'value: '+extended2str(tai_realconst(hp).value.s80val));
{$endif cpuextended}
              aitrealconst_s64comp:
                AsmWriteLn(target_asm.comment+'value: '+extended2str(tai_realconst(hp).value.s64compval));
              else
                internalerror(2014050604);
            end;
          end;
        case hp.realtyp of
          aitrealconst_s32bit:
            AsmWriteln(llvmdoubletostr(hp.value.s32val));
          aitrealconst_s64bit:
            AsmWriteln(llvmdoubletostr(hp.value.s64val));
{$if defined(cpuextended) and defined(FPC_HAS_TYPE_EXTENDED)}
          aitrealconst_s80bit:
            AsmWriteln(llvmextendedtostr(hp.value.s80val));
{$endif defined(cpuextended)}
          aitrealconst_s64comp:
            { handled as int64 most of the time in llvm }
            AsmWriteln(tostr(round(hp.value.s64compval)));
          else
            internalerror(2014062401);
        end;
      end;


    procedure TLLVMAssember.WriteOrdConst(hp: tai_const);
      var
        consttyp: taiconst_type;
      begin
        if fdecllevel=0 then
          asmwrite(target_asm.comment+' const ');
        consttyp:=hp.consttype;
        case consttyp of
          aitconst_got,
          aitconst_gotoff_symbol,
          aitconst_uleb128bit,
          aitconst_sleb128bit,
          aitconst_rva_symbol,
          aitconst_secrel32_symbol,
          aitconst_darwin_dwarf_delta32,
          aitconst_darwin_dwarf_delta64,
          aitconst_half16bit:
            internalerror(2014052901);
          aitconst_128bit,
          aitconst_64bit,
          aitconst_32bit,
          aitconst_16bit,
          aitconst_8bit,
          aitconst_16bit_unaligned,
          aitconst_32bit_unaligned,
          aitconst_64bit_unaligned:
            begin
              { can't have compile-time differences between symbols; these are
                normally for PIC, but llvm takes care of that for us }
              if assigned(hp.endsym) then
                internalerror(2014052902);
              if assigned(hp.sym) then
                begin
                  { type of struct vs type of field; type of asmsym? }
{                  if hp.value<>0 then
                    xxx }
                  AsmWrite(hp.sym.name);
                  if hp.value<>0 then
                    AsmWrite(tostr_with_plus(hp.value));
                end
              else
                AsmWrite(tostr(hp.value));
              AsmLn;
            end;
          else
            internalerror(200704251);
        end;
      end;


    procedure TLLVMAssember.WriteTai(const replaceforbidden: boolean; const do_line: boolean; var InlineLevel: cardinal; var hp: tai);

      procedure WriteTypedConstData(hp: tai_abstracttypedconst);
        var
          p: tai_abstracttypedconst;
          pval: tai;
          defstr: TSymStr;
          first, gotstring: boolean;
        begin
          { special case: tck_simple_procvar2proc; this means that we want the
            procdef of the procvardef, rather than both the procdef and the
            method/nestedfp/... pointers }
          if hp.adetyp<>tck_simple_procvar2proc then
            defstr:=llvmencodetype(hp.def)
          else
            defstr:=llvmencodeproctype(tabstractprocdef(hp.def),'',lpd_procvar);
          { write the struct, array or simple type }
          case hp.adetyp of
            tck_record:
              begin
                AsmWrite(defstr);
                AsmWrite(' ');
                AsmWrite('<{');
                first:=true;
                for p in tai_aggregatetypedconst(hp) do
                  begin
                    if not first then
                      AsmWrite(', ')
                    else
                      first:=false;
                    WriteTypedConstData(p);
                  end;
                AsmWrite('}>');
              end;
            tck_array:
              begin
                AsmWrite(defstr);
                first:=true;
                gotstring:=false;
                for p in tai_aggregatetypedconst(hp) do
                  begin
                    if not first then
                      AsmWrite(',')
                    else
                      begin
                        AsmWrite(' ');
                        if (tai_abstracttypedconst(p).adetyp=tck_simple) and
                           (tai_simpletypedconst(p).val.typ=ait_string) then
                          begin
                            gotstring:=true;
                          end
                        else
                          begin
                            AsmWrite('[');
                          end;
                        first:=false;
                      end;
                    { cannot concat strings and other things }
                    if gotstring and
                       ((tai_abstracttypedconst(p).adetyp<>tck_simple) or
                        (tai_simpletypedconst(p).val.typ<>ait_string)) then
                      internalerror(2014062701);
                    WriteTypedConstData(p);
                  end;
                if not gotstring then
                  AsmWrite(']');
              end;
            tck_simple,
            tck_simple_procvar2proc:
              begin
                pval:=tai_simpletypedconst(hp).val;
                if pval.typ<>ait_string then
                  begin
                    AsmWrite(defstr);
                    AsmWrite(' ');
                  end;
                WriteTai(replaceforbidden,do_line,InlineLevel,pval);
              end;
          end;
        end;

      var
        hp2: tai;
        s: string;
      begin
        case hp.typ of
          ait_comment :
            begin
              AsmWrite(target_asm.comment);
              AsmWritePChar(tai_comment(hp).str);
              AsmLn;
            end;

          ait_regalloc :
            begin
              if (cs_asm_regalloc in current_settings.globalswitches) then
                begin
                  AsmWrite(#9+target_asm.comment+'Register ');
                  repeat
                    AsmWrite(std_regname(Tai_regalloc(hp).reg));
                     if (hp.next=nil) or
                       (tai(hp.next).typ<>ait_regalloc) or
                       (tai_regalloc(hp.next).ratype<>tai_regalloc(hp).ratype) then
                      break;
                    hp:=tai(hp.next);
                    AsmWrite(',');
                  until false;
                  AsmWrite(' ');
                  AsmWriteLn(regallocstr[tai_regalloc(hp).ratype]);
                end;
            end;

          ait_tempalloc :
            begin
              if (cs_asm_tempalloc in current_settings.globalswitches) then
                WriteTempalloc(tai_tempalloc(hp));
            end;

          ait_align :
            begin
              { has to be specified as part of the symbol declaration }
              AsmWriteln('; error: explicit aligns are forbidden');
//             internalerror(2013010714);
            end;

          ait_section :
            begin
              AsmWrite(target_asm.comment);
              AsmWriteln('section');
            end;

          ait_datablock :
            begin
              AsmWrite(target_asm.comment);
              AsmWriteln('datablock');
            end;

          ait_const:
            begin
              WriteOrdConst(tai_const(hp));
            end;

          ait_realconst :
            begin
              WriteRealConst(tai_realconst(hp), do_line);
            end;

          ait_string :
            begin
              AsmWrite(target_asm.comment);
              AsmWriteln('string');
            end;

          ait_label :
            begin
              if (tai_label(hp).labsym.is_used) then
                begin
                  if (tai_label(hp).labsym.bind=AB_PRIVATE_EXTERN) then
                    begin
                     { should be emitted as part of the variable/function def }
                     internalerror(2013010703);
                   end;
                 if tai_label(hp).labsym.bind in [AB_GLOBAL, AB_PRIVATE_EXTERN] then
                   begin
                     { should be emitted as part of the variable/function def }
                     //internalerror(2013010704);
                     AsmWriteln(target_asm.comment+'global/privateextern label: '+tai_label(hp).labsym.name);
                   end;
                 if replaceforbidden then
                   AsmWrite(ReplaceForbiddenAsmSymbolChars(tai_label(hp).labsym.name))
                 else
                   AsmWrite(tai_label(hp).labsym.name);
                 AsmWriteLn(':');
               end;
            end;

          ait_symbol :
            begin
              { should be emitted as part of the variable/function def }
              asmwrite('; (ait_symbol error, should be part of variable/function def) :');
              asmwriteln(tai_symbol(hp).sym.name);
//             internalerror(2013010705);
            end;
          ait_llvmdecl:
            begin
              if taillvmdecl(hp).def.typ=procdef then
                begin
                  if taillvmdecl(hp).namesym.bind in [AB_EXTERNAL, AB_WEAK_EXTERNAL] then
                    begin
                      asmwrite('declare');
                      asmwriteln(llvmencodeproctype(tprocdef(taillvmdecl(hp).def), taillvmdecl(hp).namesym.name, lpd_decl));
                    end
                  else
                    begin
                      asmwrite('define');
                      asmwrite(llvmencodeproctype(tprocdef(taillvmdecl(hp).def), '', lpd_decl));
                      asmwriteln(' {');
                    end;
                end
              else
                begin
                  asmwrite(taillvmdecl(hp).namesym.name);
                  case taillvmdecl(hp).namesym.bind of
                    AB_EXTERNAL:
                      asmwrite(' = external global ');
                    AB_COMMON:
                      asmwrite(' = common global ');
                    AB_LOCAL:
                      asmwrite(' = internal global ');
                    AB_GLOBAL:
                      asmwrite(' = global ');
                    AB_WEAK_EXTERNAL:
                      asmwrite(' = extern_weak global ');
                    AB_PRIVATE_EXTERN:
                      asmwrite('= linker_private global ');
                    else
                      internalerror(2014020104);
                  end;
                  if not assigned(taillvmdecl(hp).initdata) then
                    begin
                      asmwrite(llvmencodetype(taillvmdecl(hp).def));
                      if not(taillvmdecl(hp).namesym.bind in [AB_EXTERNAL, AB_WEAK_EXTERNAL]) then
                        asmwrite(' zeroinitializer');
                    end
                  else
                    begin
                      inc(fdecllevel);
                      { can't have an external symbol with initialisation data }
                      if taillvmdecl(hp).namesym.bind in [AB_EXTERNAL, AB_WEAK_EXTERNAL] then
                        internalerror(2014052905);
                      { bitcast initialisation data to the type of the constant }
                      { write initialisation data }
                      hp2:=tai(taillvmdecl(hp).initdata.first);
                      while assigned(hp2) do
                        begin
                          WriteTai(replaceforbidden,do_line,InlineLevel,hp2);
                          hp2:=tai(hp2.next);
                        end;
                      dec(fdecllevel);
                    end;
                  { alignment }
                  asmwrite(', align ');
                  asmwriteln(tostr(taillvmdecl(hp).def.alignment));
                end;
            end;
          ait_llvmalias:
            begin
              asmwrite('@'+taillvmalias(hp).newsym.name);
              asmwrite(' = alias ');
              if taillvmalias(hp).linkage<>lll_default then
                begin
                  str(taillvmalias(hp).linkage, s);
                  asmwrite(copy(s, length('lll_'), 255));
                  asmwrite(' ');
                end
              else
                asmwrite('external ');
              if taillvmalias(hp).vis<>llv_default then
                begin
                  str(taillvmalias(hp).vis, s);
                  asmwrite(copy(s, length('llv_'), 255));
                  asmwrite(' ');
                end;
              asmwrite(llvmencodeproctype(tabstractprocdef(taillvmalias(hp).def), '', lpd_alias));
              asmwrite('* ');
              asmwriteln(taillvmalias(hp).oldsym.name);
            end;
         {$ifdef arm}
          ait_thumb_func:
            begin
              { should be emitted as part of the function def }
              internalerror(2013010706);
            end;
          ait_thumb_set:
            begin
              { should be emitted as part of the symbol def }
              internalerror(2013010707);
            end;
         {$endif arm}
          ait_set:
            begin
              { should be emitted as part of the symbol def }
              internalerror(2013010708);
            end;

          ait_weak:
            begin
              { should be emitted as part of the symbol def }
              internalerror(2013010709);
            end;

          ait_symbol_end :
            begin
              if tai_symbol_end(hp).sym.typ=AT_FUNCTION then
                asmwriteln('}')
              else
                asmwriteln('; ait_symbol_end error, should not be generated');
//                internalerror(2013010711);
            end;

          ait_instruction :
            begin
              WriteInstruction(hp);
            end;

          ait_llvmins:
            begin
              WriteLlvmInstruction(hp);
            end;

          ait_stab :
            begin
              internalerror(2013010712);
            end;

          ait_force_line,
          ait_function_name :
            ;

          ait_cutobject :
            begin
            end;

          ait_marker :
            if tai_marker(hp).kind=mark_NoLineInfoStart then
              inc(InlineLevel)
            else if tai_marker(hp).kind=mark_NoLineInfoEnd then
              dec(InlineLevel);

          ait_directive :
            begin
              WriteDirectiveName(tai_directive(hp).directive);
              if tai_directive(hp).name <>'' then
                AsmWrite(tai_directive(hp).name);
              AsmLn;
            end;

          ait_seh_directive :
            begin
              internalerror(2013010713);
            end;
          ait_varloc:
            begin
              if tai_varloc(hp).newlocationhi<>NR_NO then
                AsmWrite(strpnew('Var '+tai_varloc(hp).varsym.realname+' located in register '+
                  std_regname(tai_varloc(hp).newlocationhi)+':'+std_regname(tai_varloc(hp).newlocation)))
              else
                AsmWrite(strpnew('Var '+tai_varloc(hp).varsym.realname+' located in register '+
                  std_regname(tai_varloc(hp).newlocation)));
              AsmLn;
            end;
           ait_typedconst:
             begin
               WriteTypedConstData(tai_abstracttypedconst(hp));
             end
          else
            internalerror(2006012201);
        end;
      end;


    constructor TLLVMAssember.create(smart: boolean);
      begin
        inherited create(smart);
        InstrWriter:=TLLVMInstrWriter.create(self);
      end;


    procedure TLLVMAssember.AsmLn;
      begin
        { don't write newlines in the middle of declarations }
        if fdecllevel=0 then
          inherited AsmLn;
      end;



    procedure TLLVMAssember.WriteDirectiveName(dir: TAsmDirective);
      begin
        AsmWrite('.'+directivestr[dir]+' ');
      end;


    procedure TLLVMAssember.WriteAsmList;
      var
        n : string;
        hal : tasmlisttype;
        i: longint;
      begin

        if current_module.mainsource<>'' then
          n:=ExtractFileName(current_module.mainsource)
        else
          n:=InputFileName;

        { gcc does not add it either for Darwin. Grep for
          TARGET_ASM_FILE_START_FILE_DIRECTIVE in gcc/config/*.h
        }
        if not(target_info.system in systems_darwin) then
          AsmWriteLn(#9'.file "'+FixFileName(n)+'"');

        WriteExtraHeader;
        AsmStartSize:=AsmSize;
        symendcount:=0;

        for hal:=low(TasmlistType) to high(TasmlistType) do
          begin
            AsmWriteLn(target_asm.comment+'Begin asmlist '+AsmlistTypeStr[hal]);
            writetree(current_asmdata.asmlists[hal]);
            AsmWriteLn(target_asm.comment+'End asmlist '+AsmlistTypeStr[hal]);
          end;

        { add weak symbol markers }
        for i:=0 to current_asmdata.asmsymboldict.count-1 do
          if (tasmsymbol(current_asmdata.asmsymboldict[i]).bind=AB_WEAK_EXTERNAL) then
            writeweaksymboldef(tasmsymbol(current_asmdata.asmsymboldict[i]));

        AsmLn;
      end;



{****************************************************************************}
{                        Abstract Instruction Writer                         }
{****************************************************************************}

     constructor TLLVMInstrWriter.create(_owner: TLLVMAssember);
       begin
         inherited create;
         owner := _owner;
       end;


   const
     as_llvm_info : tasminfo =
        (
          id     : as_llvm;

          idtxt  : 'LLVM-AS';
          asmbin : 'llc';
          asmcmd: '$OPT -o $OBJ $ASM';
          supported_targets : [system_x86_64_linux,system_x86_64_darwin,system_powerpc64_darwin];
          flags : [af_smartlink_sections];
          labelprefix : 'L';
          comment : '; ';
          dollarsign: '$';
        );


begin
  RegisterAssembler(as_llvm_info,TLLVMAssember);
end.