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 "InstPrinter/X86ATTInstPrinter.h"
17#include "MCTargetDesc/X86BaseInfo.h"
18#include "X86InstrInfo.h"
19#include "X86MachineFunctionInfo.h"
20#include "llvm/ADT/SmallString.h"
21#include "llvm/CodeGen/MachineConstantPool.h"
22#include "llvm/CodeGen/MachineModuleInfoImpls.h"
23#include "llvm/CodeGen/MachineValueType.h"
24#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
25#include "llvm/IR/DebugInfo.h"
26#include "llvm/IR/DerivedTypes.h"
27#include "llvm/IR/Mangler.h"
28#include "llvm/IR/Module.h"
29#include "llvm/IR/Type.h"
30#include "llvm/MC/MCAsmInfo.h"
31#include "llvm/MC/MCContext.h"
32#include "llvm/MC/MCExpr.h"
33#include "llvm/MC/MCSectionCOFF.h"
34#include "llvm/MC/MCSectionMachO.h"
35#include "llvm/MC/MCStreamer.h"
36#include "llvm/MC/MCSymbol.h"
37#include "llvm/Support/COFF.h"
38#include "llvm/Support/Debug.h"
39#include "llvm/Support/ErrorHandling.h"
40#include "llvm/Support/TargetRegistry.h"
41using namespace llvm;
42
43//===----------------------------------------------------------------------===//
44// Primitive Helper Functions.
45//===----------------------------------------------------------------------===//
46
47/// runOnMachineFunction - Emit the function body.
48///
49bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
50  Subtarget = &MF.getSubtarget<X86Subtarget>();
51
52  SMShadowTracker.startFunction(MF);
53
54  SetupMachineFunction(MF);
55
56  if (Subtarget->isTargetCOFF()) {
57    bool Intrn = MF.getFunction()->hasInternalLinkage();
58    OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
59    OutStreamer->EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
60                                            : COFF::IMAGE_SYM_CLASS_EXTERNAL);
61    OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
62                                               << COFF::SCT_COMPLEX_TYPE_SHIFT);
63    OutStreamer->EndCOFFSymbolDef();
64  }
65
66  // Emit the rest of the function body.
67  EmitFunctionBody();
68
69  // We didn't modify anything.
70  return false;
71}
72
73/// printSymbolOperand - Print a raw symbol reference operand.  This handles
74/// jump tables, constant pools, global address and external symbols, all of
75/// which print to a label with various suffixes for relocation types etc.
76static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
77                               raw_ostream &O) {
78  switch (MO.getType()) {
79  default: llvm_unreachable("unknown symbol type!");
80  case MachineOperand::MO_ConstantPoolIndex:
81    P.GetCPISymbol(MO.getIndex())->print(O, P.MAI);
82    P.printOffset(MO.getOffset(), O);
83    break;
84  case MachineOperand::MO_GlobalAddress: {
85    const GlobalValue *GV = MO.getGlobal();
86
87    MCSymbol *GVSym;
88    if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
89      GVSym = P.getSymbolWithGlobalValueBase(GV, "$stub");
90    else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
91             MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
92             MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
93      GVSym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
94    else
95      GVSym = P.getSymbol(GV);
96
97    // Handle dllimport linkage.
98    if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
99      GVSym =
100          P.OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
101
102    if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
103        MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
104      MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
105      MachineModuleInfoImpl::StubValueTy &StubSym =
106          P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
107      if (!StubSym.getPointer())
108        StubSym = MachineModuleInfoImpl::
109          StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
110    } else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
111      MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
112      MachineModuleInfoImpl::StubValueTy &StubSym =
113          P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(
114              Sym);
115      if (!StubSym.getPointer())
116        StubSym = MachineModuleInfoImpl::
117          StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
118    } else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
119      MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$stub");
120      MachineModuleInfoImpl::StubValueTy &StubSym =
121          P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
122      if (!StubSym.getPointer())
123        StubSym = MachineModuleInfoImpl::
124          StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
125    }
126
127    // If the name begins with a dollar-sign, enclose it in parens.  We do this
128    // to avoid having it look like an integer immediate to the assembler.
129    if (GVSym->getName()[0] != '$')
130      GVSym->print(O, P.MAI);
131    else {
132      O << '(';
133      GVSym->print(O, P.MAI);
134      O << ')';
135    }
136    P.printOffset(MO.getOffset(), O);
137    break;
138  }
139  }
140
141  switch (MO.getTargetFlags()) {
142  default:
143    llvm_unreachable("Unknown target flag on GV operand");
144  case X86II::MO_NO_FLAG:    // No flag.
145    break;
146  case X86II::MO_DARWIN_NONLAZY:
147  case X86II::MO_DLLIMPORT:
148  case X86II::MO_DARWIN_STUB:
149    // These affect the name of the symbol, not any suffix.
150    break;
151  case X86II::MO_GOT_ABSOLUTE_ADDRESS:
152    O << " + [.-";
153    P.MF->getPICBaseSymbol()->print(O, P.MAI);
154    O << ']';
155    break;
156  case X86II::MO_PIC_BASE_OFFSET:
157  case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
158  case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
159    O << '-';
160    P.MF->getPICBaseSymbol()->print(O, P.MAI);
161    break;
162  case X86II::MO_TLSGD:     O << "@TLSGD";     break;
163  case X86II::MO_TLSLD:     O << "@TLSLD";     break;
164  case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
165  case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
166  case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
167  case X86II::MO_TPOFF:     O << "@TPOFF";     break;
168  case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
169  case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
170  case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
171  case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
172  case X86II::MO_GOT:       O << "@GOT";       break;
173  case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
174  case X86II::MO_PLT:       O << "@PLT";       break;
175  case X86II::MO_TLVP:      O << "@TLVP";      break;
176  case X86II::MO_TLVP_PIC_BASE:
177    O << "@TLVP" << '-';
178    P.MF->getPICBaseSymbol()->print(O, P.MAI);
179    break;
180  case X86II::MO_SECREL:    O << "@SECREL32";  break;
181  }
182}
183
184static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
185                         unsigned OpNo, raw_ostream &O,
186                         const char *Modifier = nullptr, unsigned AsmVariant = 0);
187
188/// printPCRelImm - This is used to print an immediate value that ends up
189/// being encoded as a pc-relative value.  These print slightly differently, for
190/// example, a $ is not emitted.
191static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
192                          unsigned OpNo, raw_ostream &O) {
193  const MachineOperand &MO = MI->getOperand(OpNo);
194  switch (MO.getType()) {
195  default: llvm_unreachable("Unknown pcrel immediate operand");
196  case MachineOperand::MO_Register:
197    // pc-relativeness was handled when computing the value in the reg.
198    printOperand(P, MI, OpNo, O);
199    return;
200  case MachineOperand::MO_Immediate:
201    O << MO.getImm();
202    return;
203  case MachineOperand::MO_GlobalAddress:
204    printSymbolOperand(P, MO, O);
205    return;
206  }
207}
208
209static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
210                         unsigned OpNo, raw_ostream &O, const char *Modifier,
211                         unsigned AsmVariant) {
212  const MachineOperand &MO = MI->getOperand(OpNo);
213  switch (MO.getType()) {
214  default: llvm_unreachable("unknown operand type!");
215  case MachineOperand::MO_Register: {
216    // FIXME: Enumerating AsmVariant, so we can remove magic number.
217    if (AsmVariant == 0) O << '%';
218    unsigned Reg = MO.getReg();
219    if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
220      unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
221                      (strcmp(Modifier+6,"32") == 0) ? 32 :
222                      (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
223      Reg = getX86SubSuperRegister(Reg, Size);
224    }
225    O << X86ATTInstPrinter::getRegisterName(Reg);
226    return;
227  }
228
229  case MachineOperand::MO_Immediate:
230    if (AsmVariant == 0) O << '$';
231    O << MO.getImm();
232    return;
233
234  case MachineOperand::MO_GlobalAddress: {
235    if (AsmVariant == 0) O << '$';
236    printSymbolOperand(P, MO, O);
237    break;
238  }
239  }
240}
241
242static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
243                                 unsigned Op, raw_ostream &O,
244                                 const char *Modifier = nullptr) {
245  const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
246  const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
247  const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
248
249  // If we really don't want to print out (rip), don't.
250  bool HasBaseReg = BaseReg.getReg() != 0;
251  if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
252      BaseReg.getReg() == X86::RIP)
253    HasBaseReg = false;
254
255  // HasParenPart - True if we will print out the () part of the mem ref.
256  bool HasParenPart = IndexReg.getReg() || HasBaseReg;
257
258  switch (DispSpec.getType()) {
259  default:
260    llvm_unreachable("unknown operand type!");
261  case MachineOperand::MO_Immediate: {
262    int DispVal = DispSpec.getImm();
263    if (DispVal || !HasParenPart)
264      O << DispVal;
265    break;
266  }
267  case MachineOperand::MO_GlobalAddress:
268  case MachineOperand::MO_ConstantPoolIndex:
269    printSymbolOperand(P, DispSpec, O);
270  }
271
272  if (Modifier && strcmp(Modifier, "H") == 0)
273    O << "+8";
274
275  if (HasParenPart) {
276    assert(IndexReg.getReg() != X86::ESP &&
277           "X86 doesn't allow scaling by ESP");
278
279    O << '(';
280    if (HasBaseReg)
281      printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
282
283    if (IndexReg.getReg()) {
284      O << ',';
285      printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
286      unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
287      if (ScaleVal != 1)
288        O << ',' << ScaleVal;
289    }
290    O << ')';
291  }
292}
293
294static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
295                              unsigned Op, raw_ostream &O,
296                              const char *Modifier = nullptr) {
297  assert(isMem(MI, Op) && "Invalid memory reference!");
298  const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
299  if (Segment.getReg()) {
300    printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
301    O << ':';
302  }
303  printLeaMemReference(P, MI, Op, O, Modifier);
304}
305
306static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
307                                   unsigned Op, raw_ostream &O,
308                                   const char *Modifier = nullptr,
309                                   unsigned AsmVariant = 1) {
310  const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
311  unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
312  const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
313  const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
314  const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
315
316  // If this has a segment register, print it.
317  if (SegReg.getReg()) {
318    printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
319    O << ':';
320  }
321
322  O << '[';
323
324  bool NeedPlus = false;
325  if (BaseReg.getReg()) {
326    printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
327    NeedPlus = true;
328  }
329
330  if (IndexReg.getReg()) {
331    if (NeedPlus) O << " + ";
332    if (ScaleVal != 1)
333      O << ScaleVal << '*';
334    printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
335    NeedPlus = true;
336  }
337
338  if (!DispSpec.isImm()) {
339    if (NeedPlus) O << " + ";
340    printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
341  } else {
342    int64_t DispVal = DispSpec.getImm();
343    if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
344      if (NeedPlus) {
345        if (DispVal > 0)
346          O << " + ";
347        else {
348          O << " - ";
349          DispVal = -DispVal;
350        }
351      }
352      O << DispVal;
353    }
354  }
355  O << ']';
356}
357
358static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
359                              char Mode, raw_ostream &O) {
360  unsigned Reg = MO.getReg();
361  switch (Mode) {
362  default: return true;  // Unknown mode.
363  case 'b': // Print QImode register
364    Reg = getX86SubSuperRegister(Reg, 8);
365    break;
366  case 'h': // Print QImode high register
367    Reg = getX86SubSuperRegister(Reg, 8, true);
368    break;
369  case 'w': // Print HImode register
370    Reg = getX86SubSuperRegister(Reg, 16);
371    break;
372  case 'k': // Print SImode register
373    Reg = getX86SubSuperRegister(Reg, 32);
374    break;
375  case 'q':
376    // Print 64-bit register names if 64-bit integer registers are available.
377    // Otherwise, print 32-bit register names.
378    Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
379    break;
380  }
381
382  O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
383  return false;
384}
385
386/// PrintAsmOperand - Print out an operand for an inline asm expression.
387///
388bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
389                                    unsigned AsmVariant,
390                                    const char *ExtraCode, raw_ostream &O) {
391  // Does this asm operand have a single letter operand modifier?
392  if (ExtraCode && ExtraCode[0]) {
393    if (ExtraCode[1] != 0) return true; // Unknown modifier.
394
395    const MachineOperand &MO = MI->getOperand(OpNo);
396
397    switch (ExtraCode[0]) {
398    default:
399      // See if this is a generic print operand
400      return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
401    case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
402      switch (MO.getType()) {
403      default:
404        return true;
405      case MachineOperand::MO_Immediate:
406        O << MO.getImm();
407        return false;
408      case MachineOperand::MO_ConstantPoolIndex:
409      case MachineOperand::MO_JumpTableIndex:
410      case MachineOperand::MO_ExternalSymbol:
411        llvm_unreachable("unexpected operand type!");
412      case MachineOperand::MO_GlobalAddress:
413        printSymbolOperand(*this, MO, O);
414        if (Subtarget->isPICStyleRIPRel())
415          O << "(%rip)";
416        return false;
417      case MachineOperand::MO_Register:
418        O << '(';
419        printOperand(*this, MI, OpNo, O);
420        O << ')';
421        return false;
422      }
423
424    case 'c': // Don't print "$" before a global var name or constant.
425      switch (MO.getType()) {
426      default:
427        printOperand(*this, MI, OpNo, O);
428        break;
429      case MachineOperand::MO_Immediate:
430        O << MO.getImm();
431        break;
432      case MachineOperand::MO_ConstantPoolIndex:
433      case MachineOperand::MO_JumpTableIndex:
434      case MachineOperand::MO_ExternalSymbol:
435        llvm_unreachable("unexpected operand type!");
436      case MachineOperand::MO_GlobalAddress:
437        printSymbolOperand(*this, MO, O);
438        break;
439      }
440      return false;
441
442    case 'A': // Print '*' before a register (it must be a register)
443      if (MO.isReg()) {
444        O << '*';
445        printOperand(*this, MI, OpNo, O);
446        return false;
447      }
448      return true;
449
450    case 'b': // Print QImode register
451    case 'h': // Print QImode high register
452    case 'w': // Print HImode register
453    case 'k': // Print SImode register
454    case 'q': // Print DImode register
455      if (MO.isReg())
456        return printAsmMRegister(*this, MO, ExtraCode[0], O);
457      printOperand(*this, MI, OpNo, O);
458      return false;
459
460    case 'P': // This is the operand of a call, treat specially.
461      printPCRelImm(*this, MI, OpNo, O);
462      return false;
463
464    case 'n':  // Negate the immediate or print a '-' before the operand.
465      // Note: this is a temporary solution. It should be handled target
466      // independently as part of the 'MC' work.
467      if (MO.isImm()) {
468        O << -MO.getImm();
469        return false;
470      }
471      O << '-';
472    }
473  }
474
475  printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
476  return false;
477}
478
479bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
480                                          unsigned OpNo, unsigned AsmVariant,
481                                          const char *ExtraCode,
482                                          raw_ostream &O) {
483  if (AsmVariant) {
484    printIntelMemReference(*this, MI, OpNo, O);
485    return false;
486  }
487
488  if (ExtraCode && ExtraCode[0]) {
489    if (ExtraCode[1] != 0) return true; // Unknown modifier.
490
491    switch (ExtraCode[0]) {
492    default: return true;  // Unknown modifier.
493    case 'b': // Print QImode register
494    case 'h': // Print QImode high register
495    case 'w': // Print HImode register
496    case 'k': // Print SImode register
497    case 'q': // Print SImode register
498      // These only apply to registers, ignore on mem.
499      break;
500    case 'H':
501      printMemReference(*this, MI, OpNo, O, "H");
502      return false;
503    case 'P': // Don't print @PLT, but do print as memory.
504      printMemReference(*this, MI, OpNo, O, "no-rip");
505      return false;
506    }
507  }
508  printMemReference(*this, MI, OpNo, O);
509  return false;
510}
511
512void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
513  const Triple &TT = TM.getTargetTriple();
514
515  if (TT.isOSBinFormatMachO())
516    OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
517
518  if (TT.isOSBinFormatCOFF()) {
519    // Emit an absolute @feat.00 symbol.  This appears to be some kind of
520    // compiler features bitfield read by link.exe.
521    if (TT.getArch() == Triple::x86) {
522      MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
523      OutStreamer->BeginCOFFSymbolDef(S);
524      OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
525      OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
526      OutStreamer->EndCOFFSymbolDef();
527      // According to the PE-COFF spec, the LSB of this value marks the object
528      // for "registered SEH".  This means that all SEH handler entry points
529      // must be registered in .sxdata.  Use of any unregistered handlers will
530      // cause the process to terminate immediately.  LLVM does not know how to
531      // register any SEH handlers, so its object files should be safe.
532      OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
533      OutStreamer->EmitAssignment(
534          S, MCConstantExpr::create(int64_t(1), MMI->getContext()));
535    }
536  }
537  OutStreamer->EmitSyntaxDirective();
538}
539
540static void
541emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
542                         MachineModuleInfoImpl::StubValueTy &MCSym) {
543  // L_foo$stub:
544  OutStreamer.EmitLabel(StubLabel);
545  //   .indirect_symbol _foo
546  OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
547
548  if (MCSym.getInt())
549    // External to current translation unit.
550    OutStreamer.EmitIntValue(0, 4/*size*/);
551  else
552    // Internal to current translation unit.
553    //
554    // When we place the LSDA into the TEXT section, the type info
555    // pointers need to be indirect and pc-rel. We accomplish this by
556    // using NLPs; however, sometimes the types are local to the file.
557    // We need to fill in the value for the NLP in those cases.
558    OutStreamer.EmitValue(
559        MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
560        4 /*size*/);
561}
562
563MCSymbol *X86AsmPrinter::GetCPISymbol(unsigned CPID) const {
564  if (Subtarget->isTargetKnownWindowsMSVC()) {
565    const MachineConstantPoolEntry &CPE =
566        MF->getConstantPool()->getConstants()[CPID];
567    if (!CPE.isMachineConstantPoolEntry()) {
568      const DataLayout &DL = MF->getDataLayout();
569      SectionKind Kind = CPE.getSectionKind(&DL);
570      const Constant *C = CPE.Val.ConstVal;
571      if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
572              getObjFileLowering().getSectionForConstant(DL, Kind, C))) {
573        if (MCSymbol *Sym = S->getCOMDATSymbol()) {
574          if (Sym->isUndefined())
575            OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global);
576          return Sym;
577        }
578      }
579    }
580  }
581
582  return AsmPrinter::GetCPISymbol(CPID);
583}
584
585void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
586  const Triple &TT = TM.getTargetTriple();
587
588  if (TT.isOSBinFormatMachO()) {
589    // All darwin targets use mach-o.
590    MachineModuleInfoMachO &MMIMacho =
591        MMI->getObjFileInfo<MachineModuleInfoMachO>();
592
593    // Output stubs for dynamically-linked functions.
594    MachineModuleInfoMachO::SymbolListTy Stubs;
595
596    Stubs = MMIMacho.GetFnStubList();
597    if (!Stubs.empty()) {
598      MCSection *TheSection = OutContext.getMachOSection(
599          "__IMPORT", "__jump_table",
600          MachO::S_SYMBOL_STUBS | MachO::S_ATTR_SELF_MODIFYING_CODE |
601              MachO::S_ATTR_PURE_INSTRUCTIONS,
602          5, SectionKind::getMetadata());
603      OutStreamer->SwitchSection(TheSection);
604
605      for (const auto &Stub : Stubs) {
606        // L_foo$stub:
607        OutStreamer->EmitLabel(Stub.first);
608        //   .indirect_symbol _foo
609        OutStreamer->EmitSymbolAttribute(Stub.second.getPointer(),
610                                         MCSA_IndirectSymbol);
611        // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
612        const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
613        OutStreamer->EmitBytes(StringRef(HltInsts, 5));
614      }
615
616      Stubs.clear();
617      OutStreamer->AddBlankLine();
618    }
619
620    // Output stubs for external and common global variables.
621    Stubs = MMIMacho.GetGVStubList();
622    if (!Stubs.empty()) {
623      MCSection *TheSection = OutContext.getMachOSection(
624          "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
625          SectionKind::getMetadata());
626      OutStreamer->SwitchSection(TheSection);
627
628      for (auto &Stub : Stubs)
629        emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
630
631      Stubs.clear();
632      OutStreamer->AddBlankLine();
633    }
634
635    Stubs = MMIMacho.GetHiddenGVStubList();
636    if (!Stubs.empty()) {
637      MCSection *TheSection = OutContext.getMachOSection(
638          "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
639          SectionKind::getMetadata());
640      OutStreamer->SwitchSection(TheSection);
641
642      for (auto &Stub : Stubs)
643        emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
644
645      Stubs.clear();
646      OutStreamer->AddBlankLine();
647    }
648
649    SM.serializeToStackMapSection();
650    FM.serializeToFaultMapSection();
651
652    // Funny Darwin hack: This flag tells the linker that no global symbols
653    // contain code that falls through to other global symbols (e.g. the obvious
654    // implementation of multiple entry points).  If this doesn't occur, the
655    // linker can safely perform dead code stripping.  Since LLVM never
656    // generates code that does this, it is always safe to set.
657    OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
658  }
659
660  if (TT.isKnownWindowsMSVCEnvironment() && MMI->usesVAFloatArgument()) {
661    StringRef SymbolName =
662        (TT.getArch() == Triple::x86_64) ? "_fltused" : "__fltused";
663    MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
664    OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
665  }
666
667  if (TT.isOSBinFormatCOFF()) {
668    const TargetLoweringObjectFileCOFF &TLOFCOFF =
669        static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
670
671    std::string Flags;
672    raw_string_ostream FlagsOS(Flags);
673
674    for (const auto &Function : M)
675      TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Function, *Mang);
676    for (const auto &Global : M.globals())
677      TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Global, *Mang);
678    for (const auto &Alias : M.aliases())
679      TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Alias, *Mang);
680
681    FlagsOS.flush();
682
683    // Output collected flags.
684    if (!Flags.empty()) {
685      OutStreamer->SwitchSection(TLOFCOFF.getDrectveSection());
686      OutStreamer->EmitBytes(Flags);
687    }
688
689    SM.serializeToStackMapSection();
690  }
691
692  if (TT.isOSBinFormatELF()) {
693    SM.serializeToStackMapSection();
694    FM.serializeToFaultMapSection();
695  }
696}
697
698//===----------------------------------------------------------------------===//
699// Target Registry Stuff
700//===----------------------------------------------------------------------===//
701
702// Force static initialization.
703extern "C" void LLVMInitializeX86AsmPrinter() {
704  RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
705  RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
706}
707