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      1 //===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file contains a printer that converts from our internal representation
     11 // of machine-dependent LLVM code to X86 machine code.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "X86AsmPrinter.h"
     16 #include "X86MCInstLower.h"
     17 #include "X86.h"
     18 #include "X86COFFMachineModuleInfo.h"
     19 #include "X86MachineFunctionInfo.h"
     20 #include "X86TargetMachine.h"
     21 #include "InstPrinter/X86ATTInstPrinter.h"
     22 #include "llvm/CallingConv.h"
     23 #include "llvm/DerivedTypes.h"
     24 #include "llvm/Module.h"
     25 #include "llvm/Type.h"
     26 #include "llvm/Analysis/DebugInfo.h"
     27 #include "llvm/Assembly/Writer.h"
     28 #include "llvm/MC/MCAsmInfo.h"
     29 #include "llvm/MC/MCContext.h"
     30 #include "llvm/MC/MCExpr.h"
     31 #include "llvm/MC/MCSectionMachO.h"
     32 #include "llvm/MC/MCStreamer.h"
     33 #include "llvm/MC/MCSymbol.h"
     34 #include "llvm/CodeGen/MachineJumpTableInfo.h"
     35 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
     36 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
     37 #include "llvm/Target/Mangler.h"
     38 #include "llvm/Target/TargetOptions.h"
     39 #include "llvm/Support/COFF.h"
     40 #include "llvm/Support/Debug.h"
     41 #include "llvm/Support/ErrorHandling.h"
     42 #include "llvm/Support/TargetRegistry.h"
     43 #include "llvm/ADT/SmallString.h"
     44 using namespace llvm;
     45 
     46 //===----------------------------------------------------------------------===//
     47 // Primitive Helper Functions.
     48 //===----------------------------------------------------------------------===//
     49 
     50 /// runOnMachineFunction - Emit the function body.
     51 ///
     52 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
     53   SetupMachineFunction(MF);
     54 
     55   if (Subtarget->isTargetCOFF() && !Subtarget->isTargetEnvMacho()) {
     56     bool Intrn = MF.getFunction()->hasInternalLinkage();
     57     OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
     58     OutStreamer.EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
     59                                               : COFF::IMAGE_SYM_CLASS_EXTERNAL);
     60     OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
     61                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
     62     OutStreamer.EndCOFFSymbolDef();
     63   }
     64 
     65   // Have common code print out the function header with linkage info etc.
     66   EmitFunctionHeader();
     67 
     68   // Emit the rest of the function body.
     69   EmitFunctionBody();
     70 
     71   // We didn't modify anything.
     72   return false;
     73 }
     74 
     75 /// printSymbolOperand - Print a raw symbol reference operand.  This handles
     76 /// jump tables, constant pools, global address and external symbols, all of
     77 /// which print to a label with various suffixes for relocation types etc.
     78 void X86AsmPrinter::printSymbolOperand(const MachineOperand &MO,
     79                                        raw_ostream &O) {
     80   switch (MO.getType()) {
     81   default: llvm_unreachable("unknown symbol type!");
     82   case MachineOperand::MO_JumpTableIndex:
     83     O << *GetJTISymbol(MO.getIndex());
     84     break;
     85   case MachineOperand::MO_ConstantPoolIndex:
     86     O << *GetCPISymbol(MO.getIndex());
     87     printOffset(MO.getOffset(), O);
     88     break;
     89   case MachineOperand::MO_GlobalAddress: {
     90     const GlobalValue *GV = MO.getGlobal();
     91 
     92     MCSymbol *GVSym;
     93     if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
     94       GVSym = GetSymbolWithGlobalValueBase(GV, "$stub");
     95     else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
     96              MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
     97              MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
     98       GVSym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
     99     else
    100       GVSym = Mang->getSymbol(GV);
    101 
    102     // Handle dllimport linkage.
    103     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
    104       GVSym = OutContext.GetOrCreateSymbol(Twine("__imp_") + GVSym->getName());
    105 
    106     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
    107         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
    108       MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
    109       MachineModuleInfoImpl::StubValueTy &StubSym =
    110         MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
    111       if (StubSym.getPointer() == 0)
    112         StubSym = MachineModuleInfoImpl::
    113           StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
    114     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
    115       MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
    116       MachineModuleInfoImpl::StubValueTy &StubSym =
    117         MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(Sym);
    118       if (StubSym.getPointer() == 0)
    119         StubSym = MachineModuleInfoImpl::
    120           StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
    121     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
    122       MCSymbol *Sym = GetSymbolWithGlobalValueBase(GV, "$stub");
    123       MachineModuleInfoImpl::StubValueTy &StubSym =
    124         MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
    125       if (StubSym.getPointer() == 0)
    126         StubSym = MachineModuleInfoImpl::
    127           StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
    128     }
    129 
    130     // If the name begins with a dollar-sign, enclose it in parens.  We do this
    131     // to avoid having it look like an integer immediate to the assembler.
    132     if (GVSym->getName()[0] != '$')
    133       O << *GVSym;
    134     else
    135       O << '(' << *GVSym << ')';
    136     printOffset(MO.getOffset(), O);
    137     break;
    138   }
    139   case MachineOperand::MO_ExternalSymbol: {
    140     const MCSymbol *SymToPrint;
    141     if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
    142       SmallString<128> TempNameStr;
    143       TempNameStr += StringRef(MO.getSymbolName());
    144       TempNameStr += StringRef("$stub");
    145 
    146       MCSymbol *Sym = GetExternalSymbolSymbol(TempNameStr.str());
    147       MachineModuleInfoImpl::StubValueTy &StubSym =
    148         MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
    149       if (StubSym.getPointer() == 0) {
    150         TempNameStr.erase(TempNameStr.end()-5, TempNameStr.end());
    151         StubSym = MachineModuleInfoImpl::
    152           StubValueTy(OutContext.GetOrCreateSymbol(TempNameStr.str()),
    153                       true);
    154       }
    155       SymToPrint = StubSym.getPointer();
    156     } else {
    157       SymToPrint = GetExternalSymbolSymbol(MO.getSymbolName());
    158     }
    159 
    160     // If the name begins with a dollar-sign, enclose it in parens.  We do this
    161     // to avoid having it look like an integer immediate to the assembler.
    162     if (SymToPrint->getName()[0] != '$')
    163       O << *SymToPrint;
    164     else
    165       O << '(' << *SymToPrint << '(';
    166     break;
    167   }
    168   }
    169 
    170   switch (MO.getTargetFlags()) {
    171   default:
    172     llvm_unreachable("Unknown target flag on GV operand");
    173   case X86II::MO_NO_FLAG:    // No flag.
    174     break;
    175   case X86II::MO_DARWIN_NONLAZY:
    176   case X86II::MO_DLLIMPORT:
    177   case X86II::MO_DARWIN_STUB:
    178     // These affect the name of the symbol, not any suffix.
    179     break;
    180   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
    181     O << " + [.-" << *MF->getPICBaseSymbol() << ']';
    182     break;
    183   case X86II::MO_PIC_BASE_OFFSET:
    184   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
    185   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
    186     O << '-' << *MF->getPICBaseSymbol();
    187     break;
    188   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
    189   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
    190   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
    191   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
    192   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
    193   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
    194   case X86II::MO_GOT:       O << "@GOT";       break;
    195   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
    196   case X86II::MO_PLT:       O << "@PLT";       break;
    197   case X86II::MO_TLVP:      O << "@TLVP";      break;
    198   case X86II::MO_TLVP_PIC_BASE:
    199     O << "@TLVP" << '-' << *MF->getPICBaseSymbol();
    200     break;
    201   case X86II::MO_SECREL:      O << "@SECREL";      break;
    202   }
    203 }
    204 
    205 /// print_pcrel_imm - This is used to print an immediate value that ends up
    206 /// being encoded as a pc-relative value.  These print slightly differently, for
    207 /// example, a $ is not emitted.
    208 void X86AsmPrinter::print_pcrel_imm(const MachineInstr *MI, unsigned OpNo,
    209                                     raw_ostream &O) {
    210   const MachineOperand &MO = MI->getOperand(OpNo);
    211   switch (MO.getType()) {
    212   default: llvm_unreachable("Unknown pcrel immediate operand");
    213   case MachineOperand::MO_Register:
    214     // pc-relativeness was handled when computing the value in the reg.
    215     printOperand(MI, OpNo, O);
    216     return;
    217   case MachineOperand::MO_Immediate:
    218     O << MO.getImm();
    219     return;
    220   case MachineOperand::MO_MachineBasicBlock:
    221     O << *MO.getMBB()->getSymbol();
    222     return;
    223   case MachineOperand::MO_GlobalAddress:
    224   case MachineOperand::MO_ExternalSymbol:
    225     printSymbolOperand(MO, O);
    226     return;
    227   }
    228 }
    229 
    230 
    231 void X86AsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
    232                                  raw_ostream &O, const char *Modifier) {
    233   const MachineOperand &MO = MI->getOperand(OpNo);
    234   switch (MO.getType()) {
    235   default: llvm_unreachable("unknown operand type!");
    236   case MachineOperand::MO_Register: {
    237     O << '%';
    238     unsigned Reg = MO.getReg();
    239     if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
    240       EVT VT = (strcmp(Modifier+6,"64") == 0) ?
    241         MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
    242                     ((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
    243       Reg = getX86SubSuperRegister(Reg, VT);
    244     }
    245     O << X86ATTInstPrinter::getRegisterName(Reg);
    246     return;
    247   }
    248 
    249   case MachineOperand::MO_Immediate:
    250     O << '$' << MO.getImm();
    251     return;
    252 
    253   case MachineOperand::MO_JumpTableIndex:
    254   case MachineOperand::MO_ConstantPoolIndex:
    255   case MachineOperand::MO_GlobalAddress:
    256   case MachineOperand::MO_ExternalSymbol: {
    257     O << '$';
    258     printSymbolOperand(MO, O);
    259     break;
    260   }
    261   }
    262 }
    263 
    264 void X86AsmPrinter::printSSECC(const MachineInstr *MI, unsigned Op,
    265                                raw_ostream &O) {
    266   unsigned char value = MI->getOperand(Op).getImm();
    267   switch (value) {
    268   default: llvm_unreachable("Invalid ssecc argument!");
    269   case    0: O << "eq"; break;
    270   case    1: O << "lt"; break;
    271   case    2: O << "le"; break;
    272   case    3: O << "unord"; break;
    273   case    4: O << "neq"; break;
    274   case    5: O << "nlt"; break;
    275   case    6: O << "nle"; break;
    276   case    7: O << "ord"; break;
    277   case    8: O << "eq_uq"; break;
    278   case    9: O << "nge"; break;
    279   case  0xa: O << "ngt"; break;
    280   case  0xb: O << "false"; break;
    281   case  0xc: O << "neq_oq"; break;
    282   case  0xd: O << "ge"; break;
    283   case  0xe: O << "gt"; break;
    284   case  0xf: O << "true"; break;
    285   case 0x10: O << "eq_os"; break;
    286   case 0x11: O << "lt_oq"; break;
    287   case 0x12: O << "le_oq"; break;
    288   case 0x13: O << "unord_s"; break;
    289   case 0x14: O << "neq_us"; break;
    290   case 0x15: O << "nlt_uq"; break;
    291   case 0x16: O << "nle_uq"; break;
    292   case 0x17: O << "ord_s"; break;
    293   case 0x18: O << "eq_us"; break;
    294   case 0x19: O << "nge_uq"; break;
    295   case 0x1a: O << "ngt_uq"; break;
    296   case 0x1b: O << "false_os"; break;
    297   case 0x1c: O << "neq_os"; break;
    298   case 0x1d: O << "ge_oq"; break;
    299   case 0x1e: O << "gt_oq"; break;
    300   case 0x1f: O << "true_us"; break;
    301   }
    302 }
    303 
    304 void X86AsmPrinter::printLeaMemReference(const MachineInstr *MI, unsigned Op,
    305                                          raw_ostream &O, const char *Modifier) {
    306   const MachineOperand &BaseReg  = MI->getOperand(Op);
    307   const MachineOperand &IndexReg = MI->getOperand(Op+2);
    308   const MachineOperand &DispSpec = MI->getOperand(Op+3);
    309 
    310   // If we really don't want to print out (rip), don't.
    311   bool HasBaseReg = BaseReg.getReg() != 0;
    312   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
    313       BaseReg.getReg() == X86::RIP)
    314     HasBaseReg = false;
    315 
    316   // HasParenPart - True if we will print out the () part of the mem ref.
    317   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
    318 
    319   if (DispSpec.isImm()) {
    320     int DispVal = DispSpec.getImm();
    321     if (DispVal || !HasParenPart)
    322       O << DispVal;
    323   } else {
    324     assert(DispSpec.isGlobal() || DispSpec.isCPI() ||
    325            DispSpec.isJTI() || DispSpec.isSymbol());
    326     printSymbolOperand(MI->getOperand(Op+3), O);
    327   }
    328 
    329   if (Modifier && strcmp(Modifier, "H") == 0)
    330     O << "+8";
    331 
    332   if (HasParenPart) {
    333     assert(IndexReg.getReg() != X86::ESP &&
    334            "X86 doesn't allow scaling by ESP");
    335 
    336     O << '(';
    337     if (HasBaseReg)
    338       printOperand(MI, Op, O, Modifier);
    339 
    340     if (IndexReg.getReg()) {
    341       O << ',';
    342       printOperand(MI, Op+2, O, Modifier);
    343       unsigned ScaleVal = MI->getOperand(Op+1).getImm();
    344       if (ScaleVal != 1)
    345         O << ',' << ScaleVal;
    346     }
    347     O << ')';
    348   }
    349 }
    350 
    351 void X86AsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
    352                                       raw_ostream &O, const char *Modifier) {
    353   assert(isMem(MI, Op) && "Invalid memory reference!");
    354   const MachineOperand &Segment = MI->getOperand(Op+4);
    355   if (Segment.getReg()) {
    356     printOperand(MI, Op+4, O, Modifier);
    357     O << ':';
    358   }
    359   printLeaMemReference(MI, Op, O, Modifier);
    360 }
    361 
    362 void X86AsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op,
    363                                   raw_ostream &O) {
    364   O << *MF->getPICBaseSymbol() << '\n';
    365   O << *MF->getPICBaseSymbol() << ':';
    366 }
    367 
    368 bool X86AsmPrinter::printAsmMRegister(const MachineOperand &MO, char Mode,
    369                                       raw_ostream &O) {
    370   unsigned Reg = MO.getReg();
    371   switch (Mode) {
    372   default: return true;  // Unknown mode.
    373   case 'b': // Print QImode register
    374     Reg = getX86SubSuperRegister(Reg, MVT::i8);
    375     break;
    376   case 'h': // Print QImode high register
    377     Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
    378     break;
    379   case 'w': // Print HImode register
    380     Reg = getX86SubSuperRegister(Reg, MVT::i16);
    381     break;
    382   case 'k': // Print SImode register
    383     Reg = getX86SubSuperRegister(Reg, MVT::i32);
    384     break;
    385   case 'q': // Print DImode register
    386     Reg = getX86SubSuperRegister(Reg, MVT::i64);
    387     break;
    388   }
    389 
    390   O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
    391   return false;
    392 }
    393 
    394 /// PrintAsmOperand - Print out an operand for an inline asm expression.
    395 ///
    396 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
    397                                     unsigned AsmVariant,
    398                                     const char *ExtraCode, raw_ostream &O) {
    399   // Does this asm operand have a single letter operand modifier?
    400   if (ExtraCode && ExtraCode[0]) {
    401     if (ExtraCode[1] != 0) return true; // Unknown modifier.
    402 
    403     const MachineOperand &MO = MI->getOperand(OpNo);
    404 
    405     switch (ExtraCode[0]) {
    406     default: return true;  // Unknown modifier.
    407     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
    408       if (MO.isImm()) {
    409         O << MO.getImm();
    410         return false;
    411       }
    412       if (MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isSymbol()) {
    413         printSymbolOperand(MO, O);
    414         if (Subtarget->isPICStyleRIPRel())
    415           O << "(%rip)";
    416         return false;
    417       }
    418       if (MO.isReg()) {
    419         O << '(';
    420         printOperand(MI, OpNo, O);
    421         O << ')';
    422         return false;
    423       }
    424       return true;
    425 
    426     case 'c': // Don't print "$" before a global var name or constant.
    427       if (MO.isImm())
    428         O << MO.getImm();
    429       else if (MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isSymbol())
    430         printSymbolOperand(MO, O);
    431       else
    432         printOperand(MI, OpNo, O);
    433       return false;
    434 
    435     case 'A': // Print '*' before a register (it must be a register)
    436       if (MO.isReg()) {
    437         O << '*';
    438         printOperand(MI, OpNo, O);
    439         return false;
    440       }
    441       return true;
    442 
    443     case 'b': // Print QImode register
    444     case 'h': // Print QImode high register
    445     case 'w': // Print HImode register
    446     case 'k': // Print SImode register
    447     case 'q': // Print DImode register
    448       if (MO.isReg())
    449         return printAsmMRegister(MO, ExtraCode[0], O);
    450       printOperand(MI, OpNo, O);
    451       return false;
    452 
    453     case 'P': // This is the operand of a call, treat specially.
    454       print_pcrel_imm(MI, OpNo, O);
    455       return false;
    456 
    457     case 'n':  // Negate the immediate or print a '-' before the operand.
    458       // Note: this is a temporary solution. It should be handled target
    459       // independently as part of the 'MC' work.
    460       if (MO.isImm()) {
    461         O << -MO.getImm();
    462         return false;
    463       }
    464       O << '-';
    465     }
    466   }
    467 
    468   printOperand(MI, OpNo, O);
    469   return false;
    470 }
    471 
    472 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
    473                                           unsigned OpNo, unsigned AsmVariant,
    474                                           const char *ExtraCode,
    475                                           raw_ostream &O) {
    476   if (ExtraCode && ExtraCode[0]) {
    477     if (ExtraCode[1] != 0) return true; // Unknown modifier.
    478 
    479     switch (ExtraCode[0]) {
    480     default: return true;  // Unknown modifier.
    481     case 'b': // Print QImode register
    482     case 'h': // Print QImode high register
    483     case 'w': // Print HImode register
    484     case 'k': // Print SImode register
    485     case 'q': // Print SImode register
    486       // These only apply to registers, ignore on mem.
    487       break;
    488     case 'H':
    489       printMemReference(MI, OpNo, O, "H");
    490       return false;
    491     case 'P': // Don't print @PLT, but do print as memory.
    492       printMemReference(MI, OpNo, O, "no-rip");
    493       return false;
    494     }
    495   }
    496   printMemReference(MI, OpNo, O);
    497   return false;
    498 }
    499 
    500 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
    501   if (Subtarget->isTargetEnvMacho())
    502     OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
    503 }
    504 
    505 
    506 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
    507   if (Subtarget->isTargetEnvMacho()) {
    508     // All darwin targets use mach-o.
    509     MachineModuleInfoMachO &MMIMacho =
    510       MMI->getObjFileInfo<MachineModuleInfoMachO>();
    511 
    512     // Output stubs for dynamically-linked functions.
    513     MachineModuleInfoMachO::SymbolListTy Stubs;
    514 
    515     Stubs = MMIMacho.GetFnStubList();
    516     if (!Stubs.empty()) {
    517       const MCSection *TheSection =
    518         OutContext.getMachOSection("__IMPORT", "__jump_table",
    519                                    MCSectionMachO::S_SYMBOL_STUBS |
    520                                    MCSectionMachO::S_ATTR_SELF_MODIFYING_CODE |
    521                                    MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
    522                                    5, SectionKind::getMetadata());
    523       OutStreamer.SwitchSection(TheSection);
    524 
    525       for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
    526         // L_foo$stub:
    527         OutStreamer.EmitLabel(Stubs[i].first);
    528         //   .indirect_symbol _foo
    529         OutStreamer.EmitSymbolAttribute(Stubs[i].second.getPointer(),
    530                                         MCSA_IndirectSymbol);
    531         // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
    532         const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
    533         OutStreamer.EmitBytes(StringRef(HltInsts, 5), 0/*addrspace*/);
    534       }
    535 
    536       Stubs.clear();
    537       OutStreamer.AddBlankLine();
    538     }
    539 
    540     // Output stubs for external and common global variables.
    541     Stubs = MMIMacho.GetGVStubList();
    542     if (!Stubs.empty()) {
    543       const MCSection *TheSection =
    544         OutContext.getMachOSection("__IMPORT", "__pointers",
    545                                    MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
    546                                    SectionKind::getMetadata());
    547       OutStreamer.SwitchSection(TheSection);
    548 
    549       for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
    550         // L_foo$non_lazy_ptr:
    551         OutStreamer.EmitLabel(Stubs[i].first);
    552         // .indirect_symbol _foo
    553         MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
    554         OutStreamer.EmitSymbolAttribute(MCSym.getPointer(),
    555                                         MCSA_IndirectSymbol);
    556         // .long 0
    557         if (MCSym.getInt())
    558           // External to current translation unit.
    559           OutStreamer.EmitIntValue(0, 4/*size*/, 0/*addrspace*/);
    560         else
    561           // Internal to current translation unit.
    562           //
    563           // When we place the LSDA into the TEXT section, the type info
    564           // pointers need to be indirect and pc-rel. We accomplish this by
    565           // using NLPs.  However, sometimes the types are local to the file. So
    566           // we need to fill in the value for the NLP in those cases.
    567           OutStreamer.EmitValue(MCSymbolRefExpr::Create(MCSym.getPointer(),
    568                                                         OutContext),
    569                                 4/*size*/, 0/*addrspace*/);
    570       }
    571       Stubs.clear();
    572       OutStreamer.AddBlankLine();
    573     }
    574 
    575     Stubs = MMIMacho.GetHiddenGVStubList();
    576     if (!Stubs.empty()) {
    577       OutStreamer.SwitchSection(getObjFileLowering().getDataSection());
    578       EmitAlignment(2);
    579 
    580       for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
    581         // L_foo$non_lazy_ptr:
    582         OutStreamer.EmitLabel(Stubs[i].first);
    583         // .long _foo
    584         OutStreamer.EmitValue(MCSymbolRefExpr::
    585                               Create(Stubs[i].second.getPointer(),
    586                                      OutContext),
    587                               4/*size*/, 0/*addrspace*/);
    588       }
    589       Stubs.clear();
    590       OutStreamer.AddBlankLine();
    591     }
    592 
    593     // Funny Darwin hack: This flag tells the linker that no global symbols
    594     // contain code that falls through to other global symbols (e.g. the obvious
    595     // implementation of multiple entry points).  If this doesn't occur, the
    596     // linker can safely perform dead code stripping.  Since LLVM never
    597     // generates code that does this, it is always safe to set.
    598     OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
    599   }
    600 
    601   if (Subtarget->isTargetWindows() && !Subtarget->isTargetCygMing() &&
    602       MMI->usesVAFloatArgument()) {
    603     StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
    604     MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
    605     OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
    606   }
    607 
    608   if (Subtarget->isTargetCOFF() && !Subtarget->isTargetEnvMacho()) {
    609     X86COFFMachineModuleInfo &COFFMMI =
    610       MMI->getObjFileInfo<X86COFFMachineModuleInfo>();
    611 
    612     // Emit type information for external functions
    613     typedef X86COFFMachineModuleInfo::externals_iterator externals_iterator;
    614     for (externals_iterator I = COFFMMI.externals_begin(),
    615                             E = COFFMMI.externals_end();
    616                             I != E; ++I) {
    617       OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
    618       OutStreamer.EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
    619       OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
    620                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
    621       OutStreamer.EndCOFFSymbolDef();
    622     }
    623 
    624     // Necessary for dllexport support
    625     std::vector<const MCSymbol*> DLLExportedFns, DLLExportedGlobals;
    626 
    627     const TargetLoweringObjectFileCOFF &TLOFCOFF =
    628       static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
    629 
    630     for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I)
    631       if (I->hasDLLExportLinkage())
    632         DLLExportedFns.push_back(Mang->getSymbol(I));
    633 
    634     for (Module::const_global_iterator I = M.global_begin(),
    635            E = M.global_end(); I != E; ++I)
    636       if (I->hasDLLExportLinkage())
    637         DLLExportedGlobals.push_back(Mang->getSymbol(I));
    638 
    639     // Output linker support code for dllexported globals on windows.
    640     if (!DLLExportedGlobals.empty() || !DLLExportedFns.empty()) {
    641       OutStreamer.SwitchSection(TLOFCOFF.getDrectveSection());
    642       SmallString<128> name;
    643       for (unsigned i = 0, e = DLLExportedGlobals.size(); i != e; ++i) {
    644         if (Subtarget->isTargetWindows())
    645           name = " /EXPORT:";
    646         else
    647           name = " -export:";
    648         name += DLLExportedGlobals[i]->getName();
    649         if (Subtarget->isTargetWindows())
    650           name += ",DATA";
    651         else
    652         name += ",data";
    653         OutStreamer.EmitBytes(name, 0);
    654       }
    655 
    656       for (unsigned i = 0, e = DLLExportedFns.size(); i != e; ++i) {
    657         if (Subtarget->isTargetWindows())
    658           name = " /EXPORT:";
    659         else
    660           name = " -export:";
    661         name += DLLExportedFns[i]->getName();
    662         OutStreamer.EmitBytes(name, 0);
    663       }
    664     }
    665   }
    666 
    667   if (Subtarget->isTargetELF()) {
    668     const TargetLoweringObjectFileELF &TLOFELF =
    669       static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());
    670 
    671     MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
    672 
    673     // Output stubs for external and common global variables.
    674     MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
    675     if (!Stubs.empty()) {
    676       OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
    677       const TargetData *TD = TM.getTargetData();
    678 
    679       for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
    680         OutStreamer.EmitLabel(Stubs[i].first);
    681         OutStreamer.EmitSymbolValue(Stubs[i].second.getPointer(),
    682                                     TD->getPointerSize(), 0);
    683       }
    684       Stubs.clear();
    685     }
    686   }
    687 }
    688 
    689 MachineLocation
    690 X86AsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
    691   MachineLocation Location;
    692   assert (MI->getNumOperands() == 7 && "Invalid no. of machine operands!");
    693   // Frame address.  Currently handles register +- offset only.
    694 
    695   if (MI->getOperand(0).isReg() && MI->getOperand(3).isImm())
    696     Location.set(MI->getOperand(0).getReg(), MI->getOperand(3).getImm());
    697   else {
    698     DEBUG(dbgs() << "DBG_VALUE instruction ignored! " << *MI << "\n");
    699   }
    700   return Location;
    701 }
    702 
    703 void X86AsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
    704                                            raw_ostream &O) {
    705   // Only the target-dependent form of DBG_VALUE should get here.
    706   // Referencing the offset and metadata as NOps-2 and NOps-1 is
    707   // probably portable to other targets; frame pointer location is not.
    708   unsigned NOps = MI->getNumOperands();
    709   assert(NOps==7);
    710   O << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
    711   // cast away const; DIetc do not take const operands for some reason.
    712   DIVariable V(const_cast<MDNode *>(MI->getOperand(NOps-1).getMetadata()));
    713   if (V.getContext().isSubprogram())
    714     O << DISubprogram(V.getContext()).getDisplayName() << ":";
    715   O << V.getName();
    716   O << " <- ";
    717   // Frame address.  Currently handles register +- offset only.
    718   O << '[';
    719   if (MI->getOperand(0).isReg() && MI->getOperand(0).getReg())
    720     printOperand(MI, 0, O);
    721   else
    722     O << "undef";
    723   O << '+'; printOperand(MI, 3, O);
    724   O << ']';
    725   O << "+";
    726   printOperand(MI, NOps-2, O);
    727 }
    728 
    729 
    730 
    731 //===----------------------------------------------------------------------===//
    732 // Target Registry Stuff
    733 //===----------------------------------------------------------------------===//
    734 
    735 // Force static initialization.
    736 extern "C" void LLVMInitializeX86AsmPrinter() {
    737   RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
    738   RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
    739 }
    740