X86AsmPrinter.cpp revision 341825 
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 "MCTargetDesc/X86TargetStreamer.h"
19#include "X86InstrInfo.h"
20#include "X86MachineFunctionInfo.h"
21#include "llvm/BinaryFormat/COFF.h"
22#include "llvm/BinaryFormat/ELF.h"
23#include "llvm/CodeGen/MachineConstantPool.h"
24#include "llvm/CodeGen/MachineModuleInfoImpls.h"
25#include "llvm/CodeGen/TargetLoweringObjectFileImpl.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/MCCodeEmitter.h"
31#include "llvm/MC/MCContext.h"
32#include "llvm/MC/MCExpr.h"
33#include "llvm/MC/MCSectionCOFF.h"
34#include "llvm/MC/MCSectionELF.h"
35#include "llvm/MC/MCSectionMachO.h"
36#include "llvm/MC/MCStreamer.h"
37#include "llvm/MC/MCSymbol.h"
38#include "llvm/Support/Debug.h"
39#include "llvm/Support/ErrorHandling.h"
40#include "llvm/Support/MachineValueType.h"
41#include "llvm/Support/TargetRegistry.h"
42using namespace llvm;
43
44X86AsmPrinter::X86AsmPrinter(TargetMachine &TM,
45                             std::unique_ptr<MCStreamer> Streamer)
46    : AsmPrinter(TM, std::move(Streamer)), SM(*this), FM(*this) {}
47
48//===----------------------------------------------------------------------===//
49// Primitive Helper Functions.
50//===----------------------------------------------------------------------===//
51
52/// runOnMachineFunction - Emit the function body.
53///
54bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
55  Subtarget = &MF.getSubtarget<X86Subtarget>();
56
57  SMShadowTracker.startFunction(MF);
58  CodeEmitter.reset(TM.getTarget().createMCCodeEmitter(
59      *Subtarget->getInstrInfo(), *Subtarget->getRegisterInfo(),
60      MF.getContext()));
61
62  EmitFPOData =
63      Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag();
64
65  SetupMachineFunction(MF);
66
67  if (Subtarget->isTargetCOFF()) {
68    bool Local = MF.getFunction().hasLocalLinkage();
69    OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
70    OutStreamer->EmitCOFFSymbolStorageClass(
71        Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL);
72    OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
73                                               << COFF::SCT_COMPLEX_TYPE_SHIFT);
74    OutStreamer->EndCOFFSymbolDef();
75  }
76
77  // Emit the rest of the function body.
78  EmitFunctionBody();
79
80  // Emit the XRay table for this function.
81  emitXRayTable();
82
83  EmitFPOData = false;
84
85  // We didn't modify anything.
86  return false;
87}
88
89void X86AsmPrinter::EmitFunctionBodyStart() {
90  if (EmitFPOData) {
91    X86TargetStreamer *XTS =
92        static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer());
93    unsigned ParamsSize =
94        MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize();
95    XTS->emitFPOProc(CurrentFnSym, ParamsSize);
96  }
97}
98
99void X86AsmPrinter::EmitFunctionBodyEnd() {
100  if (EmitFPOData) {
101    X86TargetStreamer *XTS =
102        static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer());
103    XTS->emitFPOEndProc();
104  }
105}
106
107/// printSymbolOperand - Print a raw symbol reference operand.  This handles
108/// jump tables, constant pools, global address and external symbols, all of
109/// which print to a label with various suffixes for relocation types etc.
110static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
111                               raw_ostream &O) {
112  switch (MO.getType()) {
113  default: llvm_unreachable("unknown symbol type!");
114  case MachineOperand::MO_ConstantPoolIndex:
115    P.GetCPISymbol(MO.getIndex())->print(O, P.MAI);
116    P.printOffset(MO.getOffset(), O);
117    break;
118  case MachineOperand::MO_GlobalAddress: {
119    const GlobalValue *GV = MO.getGlobal();
120
121    MCSymbol *GVSym;
122    if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
123        MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE)
124      GVSym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
125    else
126      GVSym = P.getSymbol(GV);
127
128    // Handle dllimport linkage.
129    if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
130      GVSym =
131          P.OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
132
133    if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
134        MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
135      MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
136      MachineModuleInfoImpl::StubValueTy &StubSym =
137          P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
138      if (!StubSym.getPointer())
139        StubSym = MachineModuleInfoImpl::
140          StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
141    }
142
143    // If the name begins with a dollar-sign, enclose it in parens.  We do this
144    // to avoid having it look like an integer immediate to the assembler.
145    if (GVSym->getName()[0] != '$')
146      GVSym->print(O, P.MAI);
147    else {
148      O << '(';
149      GVSym->print(O, P.MAI);
150      O << ')';
151    }
152    P.printOffset(MO.getOffset(), O);
153    break;
154  }
155  }
156
157  switch (MO.getTargetFlags()) {
158  default:
159    llvm_unreachable("Unknown target flag on GV operand");
160  case X86II::MO_NO_FLAG:    // No flag.
161    break;
162  case X86II::MO_DARWIN_NONLAZY:
163  case X86II::MO_DLLIMPORT:
164    // These affect the name of the symbol, not any suffix.
165    break;
166  case X86II::MO_GOT_ABSOLUTE_ADDRESS:
167    O << " + [.-";
168    P.MF->getPICBaseSymbol()->print(O, P.MAI);
169    O << ']';
170    break;
171  case X86II::MO_PIC_BASE_OFFSET:
172  case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
173    O << '-';
174    P.MF->getPICBaseSymbol()->print(O, P.MAI);
175    break;
176  case X86II::MO_TLSGD:     O << "@TLSGD";     break;
177  case X86II::MO_TLSLD:     O << "@TLSLD";     break;
178  case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
179  case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
180  case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
181  case X86II::MO_TPOFF:     O << "@TPOFF";     break;
182  case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
183  case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
184  case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
185  case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
186  case X86II::MO_GOT:       O << "@GOT";       break;
187  case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
188  case X86II::MO_PLT:       O << "@PLT";       break;
189  case X86II::MO_TLVP:      O << "@TLVP";      break;
190  case X86II::MO_TLVP_PIC_BASE:
191    O << "@TLVP" << '-';
192    P.MF->getPICBaseSymbol()->print(O, P.MAI);
193    break;
194  case X86II::MO_SECREL:    O << "@SECREL32";  break;
195  }
196}
197
198static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
199                         unsigned OpNo, raw_ostream &O,
200                         const char *Modifier = nullptr, unsigned AsmVariant = 0);
201
202/// printPCRelImm - This is used to print an immediate value that ends up
203/// being encoded as a pc-relative value.  These print slightly differently, for
204/// example, a $ is not emitted.
205static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
206                          unsigned OpNo, raw_ostream &O) {
207  const MachineOperand &MO = MI->getOperand(OpNo);
208  switch (MO.getType()) {
209  default: llvm_unreachable("Unknown pcrel immediate operand");
210  case MachineOperand::MO_Register:
211    // pc-relativeness was handled when computing the value in the reg.
212    printOperand(P, MI, OpNo, O);
213    return;
214  case MachineOperand::MO_Immediate:
215    O << MO.getImm();
216    return;
217  case MachineOperand::MO_GlobalAddress:
218    printSymbolOperand(P, MO, O);
219    return;
220  }
221}
222
223static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
224                         unsigned OpNo, raw_ostream &O, const char *Modifier,
225                         unsigned AsmVariant) {
226  const MachineOperand &MO = MI->getOperand(OpNo);
227  switch (MO.getType()) {
228  default: llvm_unreachable("unknown operand type!");
229  case MachineOperand::MO_Register: {
230    // FIXME: Enumerating AsmVariant, so we can remove magic number.
231    if (AsmVariant == 0) O << '%';
232    unsigned Reg = MO.getReg();
233    if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
234      unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
235                      (strcmp(Modifier+6,"32") == 0) ? 32 :
236                      (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
237      Reg = getX86SubSuperRegister(Reg, Size);
238    }
239    O << X86ATTInstPrinter::getRegisterName(Reg);
240    return;
241  }
242
243  case MachineOperand::MO_Immediate:
244    if (AsmVariant == 0) O << '$';
245    O << MO.getImm();
246    return;
247
248  case MachineOperand::MO_GlobalAddress: {
249    if (AsmVariant == 0) O << '$';
250    printSymbolOperand(P, MO, O);
251    break;
252  }
253  }
254}
255
256static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
257                                 unsigned Op, raw_ostream &O,
258                                 const char *Modifier = nullptr) {
259  const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
260  const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
261  const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
262
263  // If we really don't want to print out (rip), don't.
264  bool HasBaseReg = BaseReg.getReg() != 0;
265  if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
266      BaseReg.getReg() == X86::RIP)
267    HasBaseReg = false;
268
269  // HasParenPart - True if we will print out the () part of the mem ref.
270  bool HasParenPart = IndexReg.getReg() || HasBaseReg;
271
272  switch (DispSpec.getType()) {
273  default:
274    llvm_unreachable("unknown operand type!");
275  case MachineOperand::MO_Immediate: {
276    int DispVal = DispSpec.getImm();
277    if (DispVal || !HasParenPart)
278      O << DispVal;
279    break;
280  }
281  case MachineOperand::MO_GlobalAddress:
282  case MachineOperand::MO_ConstantPoolIndex:
283    printSymbolOperand(P, DispSpec, O);
284  }
285
286  if (Modifier && strcmp(Modifier, "H") == 0)
287    O << "+8";
288
289  if (HasParenPart) {
290    assert(IndexReg.getReg() != X86::ESP &&
291           "X86 doesn't allow scaling by ESP");
292
293    O << '(';
294    if (HasBaseReg)
295      printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
296
297    if (IndexReg.getReg()) {
298      O << ',';
299      printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
300      unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
301      if (ScaleVal != 1)
302        O << ',' << ScaleVal;
303    }
304    O << ')';
305  }
306}
307
308static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
309                              unsigned Op, raw_ostream &O,
310                              const char *Modifier = nullptr) {
311  assert(isMem(*MI, Op) && "Invalid memory reference!");
312  const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
313  if (Segment.getReg()) {
314    printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
315    O << ':';
316  }
317  printLeaMemReference(P, MI, Op, O, Modifier);
318}
319
320static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
321                                   unsigned Op, raw_ostream &O,
322                                   const char *Modifier = nullptr,
323                                   unsigned AsmVariant = 1) {
324  const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
325  unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
326  const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
327  const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
328  const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
329
330  // If this has a segment register, print it.
331  if (SegReg.getReg()) {
332    printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
333    O << ':';
334  }
335
336  O << '[';
337
338  bool NeedPlus = false;
339  if (BaseReg.getReg()) {
340    printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
341    NeedPlus = true;
342  }
343
344  if (IndexReg.getReg()) {
345    if (NeedPlus) O << " + ";
346    if (ScaleVal != 1)
347      O << ScaleVal << '*';
348    printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
349    NeedPlus = true;
350  }
351
352  if (!DispSpec.isImm()) {
353    if (NeedPlus) O << " + ";
354    printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
355  } else {
356    int64_t DispVal = DispSpec.getImm();
357    if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
358      if (NeedPlus) {
359        if (DispVal > 0)
360          O << " + ";
361        else {
362          O << " - ";
363          DispVal = -DispVal;
364        }
365      }
366      O << DispVal;
367    }
368  }
369  O << ']';
370}
371
372static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
373                              char Mode, raw_ostream &O) {
374  unsigned Reg = MO.getReg();
375  bool EmitPercent = true;
376
377  if (!X86::GR8RegClass.contains(Reg) &&
378      !X86::GR16RegClass.contains(Reg) &&
379      !X86::GR32RegClass.contains(Reg) &&
380      !X86::GR64RegClass.contains(Reg))
381    return true;
382
383  switch (Mode) {
384  default: return true;  // Unknown mode.
385  case 'b': // Print QImode register
386    Reg = getX86SubSuperRegister(Reg, 8);
387    break;
388  case 'h': // Print QImode high register
389    Reg = getX86SubSuperRegister(Reg, 8, true);
390    break;
391  case 'w': // Print HImode register
392    Reg = getX86SubSuperRegister(Reg, 16);
393    break;
394  case 'k': // Print SImode register
395    Reg = getX86SubSuperRegister(Reg, 32);
396    break;
397  case 'V':
398    EmitPercent = false;
399    LLVM_FALLTHROUGH;
400  case 'q':
401    // Print 64-bit register names if 64-bit integer registers are available.
402    // Otherwise, print 32-bit register names.
403    Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
404    break;
405  }
406
407  if (EmitPercent)
408    O << '%';
409
410  O << X86ATTInstPrinter::getRegisterName(Reg);
411  return false;
412}
413
414/// PrintAsmOperand - Print out an operand for an inline asm expression.
415///
416bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
417                                    unsigned AsmVariant,
418                                    const char *ExtraCode, raw_ostream &O) {
419  // Does this asm operand have a single letter operand modifier?
420  if (ExtraCode && ExtraCode[0]) {
421    if (ExtraCode[1] != 0) return true; // Unknown modifier.
422
423    const MachineOperand &MO = MI->getOperand(OpNo);
424
425    switch (ExtraCode[0]) {
426    default:
427      // See if this is a generic print operand
428      return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
429    case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
430      switch (MO.getType()) {
431      default:
432        return true;
433      case MachineOperand::MO_Immediate:
434        O << MO.getImm();
435        return false;
436      case MachineOperand::MO_ConstantPoolIndex:
437      case MachineOperand::MO_JumpTableIndex:
438      case MachineOperand::MO_ExternalSymbol:
439        llvm_unreachable("unexpected operand type!");
440      case MachineOperand::MO_GlobalAddress:
441        printSymbolOperand(*this, MO, O);
442        if (Subtarget->isPICStyleRIPRel())
443          O << "(%rip)";
444        return false;
445      case MachineOperand::MO_Register:
446        O << '(';
447        printOperand(*this, MI, OpNo, O);
448        O << ')';
449        return false;
450      }
451
452    case 'c': // Don't print "$" before a global var name or constant.
453      switch (MO.getType()) {
454      default:
455        printOperand(*this, MI, OpNo, O);
456        break;
457      case MachineOperand::MO_Immediate:
458        O << MO.getImm();
459        break;
460      case MachineOperand::MO_ConstantPoolIndex:
461      case MachineOperand::MO_JumpTableIndex:
462      case MachineOperand::MO_ExternalSymbol:
463        llvm_unreachable("unexpected operand type!");
464      case MachineOperand::MO_GlobalAddress:
465        printSymbolOperand(*this, MO, O);
466        break;
467      }
468      return false;
469
470    case 'A': // Print '*' before a register (it must be a register)
471      if (MO.isReg()) {
472        O << '*';
473        printOperand(*this, MI, OpNo, O);
474        return false;
475      }
476      return true;
477
478    case 'b': // Print QImode register
479    case 'h': // Print QImode high register
480    case 'w': // Print HImode register
481    case 'k': // Print SImode register
482    case 'q': // Print DImode register
483    case 'V': // Print native register without '%'
484      if (MO.isReg())
485        return printAsmMRegister(*this, MO, ExtraCode[0], O);
486      printOperand(*this, MI, OpNo, O);
487      return false;
488
489    case 'P': // This is the operand of a call, treat specially.
490      printPCRelImm(*this, MI, OpNo, O);
491      return false;
492
493    case 'n': // Negate the immediate or print a '-' before the operand.
494      // Note: this is a temporary solution. It should be handled target
495      // independently as part of the 'MC' work.
496      if (MO.isImm()) {
497        O << -MO.getImm();
498        return false;
499      }
500      O << '-';
501    }
502  }
503
504  printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
505  return false;
506}
507
508bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
509                                          unsigned OpNo, unsigned AsmVariant,
510                                          const char *ExtraCode,
511                                          raw_ostream &O) {
512  if (AsmVariant) {
513    printIntelMemReference(*this, MI, OpNo, O);
514    return false;
515  }
516
517  if (ExtraCode && ExtraCode[0]) {
518    if (ExtraCode[1] != 0) return true; // Unknown modifier.
519
520    switch (ExtraCode[0]) {
521    default: return true;  // Unknown modifier.
522    case 'b': // Print QImode register
523    case 'h': // Print QImode high register
524    case 'w': // Print HImode register
525    case 'k': // Print SImode register
526    case 'q': // Print SImode register
527      // These only apply to registers, ignore on mem.
528      break;
529    case 'H':
530      printMemReference(*this, MI, OpNo, O, "H");
531      return false;
532    case 'P': // Don't print @PLT, but do print as memory.
533      printMemReference(*this, MI, OpNo, O, "no-rip");
534      return false;
535    }
536  }
537  printMemReference(*this, MI, OpNo, O);
538  return false;
539}
540
541void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
542  const Triple &TT = TM.getTargetTriple();
543
544  if (TT.isOSBinFormatELF()) {
545    // Assemble feature flags that may require creation of a note section.
546    unsigned FeatureFlagsAnd = 0;
547    if (M.getModuleFlag("cf-protection-branch"))
548      FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
549    if (M.getModuleFlag("cf-protection-return"))
550      FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
551
552    if (FeatureFlagsAnd) {
553      // Emit a .note.gnu.property section with the flags.
554      if (!TT.isArch32Bit() && !TT.isArch64Bit())
555        llvm_unreachable("CFProtection used on invalid architecture!");
556      MCSection *Cur = OutStreamer->getCurrentSectionOnly();
557      MCSection *Nt = MMI->getContext().getELFSection(
558          ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
559      OutStreamer->SwitchSection(Nt);
560
561      // Emitting note header.
562      int WordSize = TT.isArch64Bit() ? 8 : 4;
563      EmitAlignment(WordSize == 4 ? 2 : 3);
564      OutStreamer->EmitIntValue(4, 4 /*size*/); // data size for "GNU\0"
565      OutStreamer->EmitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
566      OutStreamer->EmitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
567      OutStreamer->EmitBytes(StringRef("GNU", 4)); // note name
568
569      // Emitting an Elf_Prop for the CET properties.
570      OutStreamer->EmitIntValue(ELF::GNU_PROPERTY_X86_FEATURE_1_AND, 4);
571      OutStreamer->EmitIntValue(WordSize, 4);               // data size
572      OutStreamer->EmitIntValue(FeatureFlagsAnd, WordSize); // data
573      EmitAlignment(WordSize == 4 ? 2 : 3);                 // padding
574
575      OutStreamer->endSection(Nt);
576      OutStreamer->SwitchSection(Cur);
577    }
578  }
579
580  if (TT.isOSBinFormatMachO())
581    OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
582
583  if (TT.isOSBinFormatCOFF()) {
584    // Emit an absolute @feat.00 symbol.  This appears to be some kind of
585    // compiler features bitfield read by link.exe.
586    if (TT.getArch() == Triple::x86) {
587      MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
588      OutStreamer->BeginCOFFSymbolDef(S);
589      OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
590      OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
591      OutStreamer->EndCOFFSymbolDef();
592      // According to the PE-COFF spec, the LSB of this value marks the object
593      // for "registered SEH".  This means that all SEH handler entry points
594      // must be registered in .sxdata.  Use of any unregistered handlers will
595      // cause the process to terminate immediately.  LLVM does not know how to
596      // register any SEH handlers, so its object files should be safe.
597      OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
598      OutStreamer->EmitAssignment(
599          S, MCConstantExpr::create(int64_t(1), MMI->getContext()));
600    }
601  }
602  OutStreamer->EmitSyntaxDirective();
603
604  // If this is not inline asm and we're in 16-bit
605  // mode prefix assembly with .code16.
606  bool is16 = TT.getEnvironment() == Triple::CODE16;
607  if (M.getModuleInlineAsm().empty() && is16)
608    OutStreamer->EmitAssemblerFlag(MCAF_Code16);
609}
610
611static void
612emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
613                         MachineModuleInfoImpl::StubValueTy &MCSym) {
614  // L_foo$stub:
615  OutStreamer.EmitLabel(StubLabel);
616  //   .indirect_symbol _foo
617  OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
618
619  if (MCSym.getInt())
620    // External to current translation unit.
621    OutStreamer.EmitIntValue(0, 4/*size*/);
622  else
623    // Internal to current translation unit.
624    //
625    // When we place the LSDA into the TEXT section, the type info
626    // pointers need to be indirect and pc-rel. We accomplish this by
627    // using NLPs; however, sometimes the types are local to the file.
628    // We need to fill in the value for the NLP in those cases.
629    OutStreamer.EmitValue(
630        MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
631        4 /*size*/);
632}
633
634static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
635
636  MachineModuleInfoMachO &MMIMacho =
637      MMI->getObjFileInfo<MachineModuleInfoMachO>();
638
639  // Output stubs for dynamically-linked functions.
640  MachineModuleInfoMachO::SymbolListTy Stubs;
641
642  // Output stubs for external and common global variables.
643  Stubs = MMIMacho.GetGVStubList();
644  if (!Stubs.empty()) {
645    OutStreamer.SwitchSection(MMI->getContext().getMachOSection(
646        "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
647        SectionKind::getMetadata()));
648
649    for (auto &Stub : Stubs)
650      emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
651
652    Stubs.clear();
653    OutStreamer.AddBlankLine();
654  }
655}
656
657void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
658  const Triple &TT = TM.getTargetTriple();
659
660  if (TT.isOSBinFormatMachO()) {
661    // Mach-O uses non-lazy symbol stubs to encode per-TU information into
662    // global table for symbol lookup.
663    emitNonLazyStubs(MMI, *OutStreamer);
664
665    // Emit stack and fault map information.
666    SM.serializeToStackMapSection();
667    FM.serializeToFaultMapSection();
668
669    // This flag tells the linker that no global symbols contain code that fall
670    // through to other global symbols (e.g. an implementation of multiple entry
671    // points). If this doesn't occur, the linker can safely perform dead code
672    // stripping. Since LLVM never generates code that does this, it is always
673    // safe to set.
674    OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
675    return;
676  }
677
678  if (TT.isKnownWindowsMSVCEnvironment() && MMI->usesVAFloatArgument()) {
679    StringRef SymbolName =
680        (TT.getArch() == Triple::x86_64) ? "_fltused" : "__fltused";
681    MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
682    OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
683    return;
684  }
685
686  if (TT.isOSBinFormatCOFF()) {
687    SM.serializeToStackMapSection();
688    return;
689  }
690
691  if (TT.isOSBinFormatELF()) {
692    SM.serializeToStackMapSection();
693    FM.serializeToFaultMapSection();
694    return;
695  }
696}
697
698//===----------------------------------------------------------------------===//
699// Target Registry Stuff
700//===----------------------------------------------------------------------===//
701
702// Force static initialization.
703extern "C" void LLVMInitializeX86AsmPrinter() {
704  RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
705  RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
706}
707