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"
42 using namespace llvm;
43 
44 X86AsmPrinter::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 ///
54 bool 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 
89 void X86AsmPrinter::EmitFunctionBodyStart() {
90   if (EmitFPOData) {
91     if (auto *XTS =
92         static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
93       XTS->emitFPOProc(
94           CurrentFnSym,
95           MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize());
96   }
97 }
98 
99 void X86AsmPrinter::EmitFunctionBodyEnd() {
100   if (EmitFPOData) {
101     if (auto *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.
110 static 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, "$non_lazy_ptr");
125     else
126       GVSym = P.getSymbol(GV);
127 
128     // Handle dllimport linkage.
129     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
130       GVSym =
131           P.OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
132     else if (MO.getTargetFlags() == X86II::MO_COFFSTUB)
133       GVSym =
134           P.OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName());
135 
136     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
137         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
138       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
139       MachineModuleInfoImpl::StubValueTy &StubSym =
140           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
141       if (!StubSym.getPointer())
142         StubSym = MachineModuleInfoImpl::
143           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
144     }
145 
146     // If the name begins with a dollar-sign, enclose it in parens.  We do this
147     // to avoid having it look like an integer immediate to the assembler.
148     if (GVSym->getName()[0] != '$')
149       GVSym->print(O, P.MAI);
150     else {
151       O << '(';
152       GVSym->print(O, P.MAI);
153       O << ')';
154     }
155     P.printOffset(MO.getOffset(), O);
156     break;
157   }
158   }
159 
160   switch (MO.getTargetFlags()) {
161   default:
162     llvm_unreachable("Unknown target flag on GV operand");
163   case X86II::MO_NO_FLAG:    // No flag.
164     break;
165   case X86II::MO_DARWIN_NONLAZY:
166   case X86II::MO_DLLIMPORT:
167   case X86II::MO_COFFSTUB:
168     // These affect the name of the symbol, not any suffix.
169     break;
170   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
171     O << " + [.-";
172     P.MF->getPICBaseSymbol()->print(O, P.MAI);
173     O << ']';
174     break;
175   case X86II::MO_PIC_BASE_OFFSET:
176   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
177     O << '-';
178     P.MF->getPICBaseSymbol()->print(O, P.MAI);
179     break;
180   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
181   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
182   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
183   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
184   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
185   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
186   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
187   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
188   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
189   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
190   case X86II::MO_GOT:       O << "@GOT";       break;
191   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
192   case X86II::MO_PLT:       O << "@PLT";       break;
193   case X86II::MO_TLVP:      O << "@TLVP";      break;
194   case X86II::MO_TLVP_PIC_BASE:
195     O << "@TLVP" << '-';
196     P.MF->getPICBaseSymbol()->print(O, P.MAI);
197     break;
198   case X86II::MO_SECREL:    O << "@SECREL32";  break;
199   }
200 }
201 
202 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
203                          unsigned OpNo, raw_ostream &O,
204                          const char *Modifier = nullptr, unsigned AsmVariant = 0);
205 
206 /// printPCRelImm - This is used to print an immediate value that ends up
207 /// being encoded as a pc-relative value.  These print slightly differently, for
208 /// example, a $ is not emitted.
209 static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
210                           unsigned OpNo, raw_ostream &O) {
211   const MachineOperand &MO = MI->getOperand(OpNo);
212   switch (MO.getType()) {
213   default: llvm_unreachable("Unknown pcrel immediate operand");
214   case MachineOperand::MO_Register:
215     // pc-relativeness was handled when computing the value in the reg.
216     printOperand(P, MI, OpNo, O);
217     return;
218   case MachineOperand::MO_Immediate:
219     O << MO.getImm();
220     return;
221   case MachineOperand::MO_GlobalAddress:
222     printSymbolOperand(P, MO, O);
223     return;
224   }
225 }
226 
227 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
228                          unsigned OpNo, raw_ostream &O, const char *Modifier,
229                          unsigned AsmVariant) {
230   const MachineOperand &MO = MI->getOperand(OpNo);
231   switch (MO.getType()) {
232   default: llvm_unreachable("unknown operand type!");
233   case MachineOperand::MO_Register: {
234     // FIXME: Enumerating AsmVariant, so we can remove magic number.
235     if (AsmVariant == 0) O << '%';
236     unsigned Reg = MO.getReg();
237     if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
238       unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
239                       (strcmp(Modifier+6,"32") == 0) ? 32 :
240                       (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
241       Reg = getX86SubSuperRegister(Reg, Size);
242     }
243     O << X86ATTInstPrinter::getRegisterName(Reg);
244     return;
245   }
246 
247   case MachineOperand::MO_Immediate:
248     if (AsmVariant == 0) O << '$';
249     O << MO.getImm();
250     return;
251 
252   case MachineOperand::MO_GlobalAddress: {
253     if (AsmVariant == 0) O << '$';
254     printSymbolOperand(P, MO, O);
255     break;
256   }
257   }
258 }
259 
260 static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
261                                  unsigned Op, raw_ostream &O,
262                                  const char *Modifier = nullptr) {
263   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
264   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
265   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
266 
267   // If we really don't want to print out (rip), don't.
268   bool HasBaseReg = BaseReg.getReg() != 0;
269   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
270       BaseReg.getReg() == X86::RIP)
271     HasBaseReg = false;
272 
273   // HasParenPart - True if we will print out the () part of the mem ref.
274   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
275 
276   switch (DispSpec.getType()) {
277   default:
278     llvm_unreachable("unknown operand type!");
279   case MachineOperand::MO_Immediate: {
280     int DispVal = DispSpec.getImm();
281     if (DispVal || !HasParenPart)
282       O << DispVal;
283     break;
284   }
285   case MachineOperand::MO_GlobalAddress:
286   case MachineOperand::MO_ConstantPoolIndex:
287     printSymbolOperand(P, DispSpec, O);
288   }
289 
290   if (Modifier && strcmp(Modifier, "H") == 0)
291     O << "+8";
292 
293   if (HasParenPart) {
294     assert(IndexReg.getReg() != X86::ESP &&
295            "X86 doesn't allow scaling by ESP");
296 
297     O << '(';
298     if (HasBaseReg)
299       printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
300 
301     if (IndexReg.getReg()) {
302       O << ',';
303       printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
304       unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
305       if (ScaleVal != 1)
306         O << ',' << ScaleVal;
307     }
308     O << ')';
309   }
310 }
311 
312 static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
313                               unsigned Op, raw_ostream &O,
314                               const char *Modifier = nullptr) {
315   assert(isMem(*MI, Op) && "Invalid memory reference!");
316   const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
317   if (Segment.getReg()) {
318     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
319     O << ':';
320   }
321   printLeaMemReference(P, MI, Op, O, Modifier);
322 }
323 
324 static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
325                                    unsigned Op, raw_ostream &O,
326                                    const char *Modifier = nullptr,
327                                    unsigned AsmVariant = 1) {
328   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
329   unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
330   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
331   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
332   const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
333 
334   // If this has a segment register, print it.
335   if (SegReg.getReg()) {
336     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
337     O << ':';
338   }
339 
340   O << '[';
341 
342   bool NeedPlus = false;
343   if (BaseReg.getReg()) {
344     printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
345     NeedPlus = true;
346   }
347 
348   if (IndexReg.getReg()) {
349     if (NeedPlus) O << " + ";
350     if (ScaleVal != 1)
351       O << ScaleVal << '*';
352     printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
353     NeedPlus = true;
354   }
355 
356   if (!DispSpec.isImm()) {
357     if (NeedPlus) O << " + ";
358     printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
359   } else {
360     int64_t DispVal = DispSpec.getImm();
361     if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
362       if (NeedPlus) {
363         if (DispVal > 0)
364           O << " + ";
365         else {
366           O << " - ";
367           DispVal = -DispVal;
368         }
369       }
370       O << DispVal;
371     }
372   }
373   O << ']';
374 }
375 
376 static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
377                               char Mode, raw_ostream &O) {
378   unsigned Reg = MO.getReg();
379   bool EmitPercent = true;
380 
381   if (!X86::GR8RegClass.contains(Reg) &&
382       !X86::GR16RegClass.contains(Reg) &&
383       !X86::GR32RegClass.contains(Reg) &&
384       !X86::GR64RegClass.contains(Reg))
385     return true;
386 
387   switch (Mode) {
388   default: return true;  // Unknown mode.
389   case 'b': // Print QImode register
390     Reg = getX86SubSuperRegister(Reg, 8);
391     break;
392   case 'h': // Print QImode high register
393     Reg = getX86SubSuperRegister(Reg, 8, true);
394     break;
395   case 'w': // Print HImode register
396     Reg = getX86SubSuperRegister(Reg, 16);
397     break;
398   case 'k': // Print SImode register
399     Reg = getX86SubSuperRegister(Reg, 32);
400     break;
401   case 'V':
402     EmitPercent = false;
403     LLVM_FALLTHROUGH;
404   case 'q':
405     // Print 64-bit register names if 64-bit integer registers are available.
406     // Otherwise, print 32-bit register names.
407     Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
408     break;
409   }
410 
411   if (EmitPercent)
412     O << '%';
413 
414   O << X86ATTInstPrinter::getRegisterName(Reg);
415   return false;
416 }
417 
418 /// PrintAsmOperand - Print out an operand for an inline asm expression.
419 ///
420 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
421                                     unsigned AsmVariant,
422                                     const char *ExtraCode, raw_ostream &O) {
423   // Does this asm operand have a single letter operand modifier?
424   if (ExtraCode && ExtraCode[0]) {
425     if (ExtraCode[1] != 0) return true; // Unknown modifier.
426 
427     const MachineOperand &MO = MI->getOperand(OpNo);
428 
429     switch (ExtraCode[0]) {
430     default:
431       // See if this is a generic print operand
432       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
433     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
434       switch (MO.getType()) {
435       default:
436         return true;
437       case MachineOperand::MO_Immediate:
438         O << MO.getImm();
439         return false;
440       case MachineOperand::MO_ConstantPoolIndex:
441       case MachineOperand::MO_JumpTableIndex:
442       case MachineOperand::MO_ExternalSymbol:
443         llvm_unreachable("unexpected operand type!");
444       case MachineOperand::MO_GlobalAddress:
445         printSymbolOperand(*this, MO, O);
446         if (Subtarget->isPICStyleRIPRel())
447           O << "(%rip)";
448         return false;
449       case MachineOperand::MO_Register:
450         O << '(';
451         printOperand(*this, MI, OpNo, O);
452         O << ')';
453         return false;
454       }
455 
456     case 'c': // Don't print "$" before a global var name or constant.
457       switch (MO.getType()) {
458       default:
459         printOperand(*this, MI, OpNo, O);
460         break;
461       case MachineOperand::MO_Immediate:
462         O << MO.getImm();
463         break;
464       case MachineOperand::MO_ConstantPoolIndex:
465       case MachineOperand::MO_JumpTableIndex:
466       case MachineOperand::MO_ExternalSymbol:
467         llvm_unreachable("unexpected operand type!");
468       case MachineOperand::MO_GlobalAddress:
469         printSymbolOperand(*this, MO, O);
470         break;
471       }
472       return false;
473 
474     case 'A': // Print '*' before a register (it must be a register)
475       if (MO.isReg()) {
476         O << '*';
477         printOperand(*this, MI, OpNo, O);
478         return false;
479       }
480       return true;
481 
482     case 'b': // Print QImode register
483     case 'h': // Print QImode high register
484     case 'w': // Print HImode register
485     case 'k': // Print SImode register
486     case 'q': // Print DImode register
487     case 'V': // Print native register without '%'
488       if (MO.isReg())
489         return printAsmMRegister(*this, MO, ExtraCode[0], O);
490       printOperand(*this, MI, OpNo, O);
491       return false;
492 
493     case 'P': // This is the operand of a call, treat specially.
494       printPCRelImm(*this, MI, OpNo, O);
495       return false;
496 
497     case 'n': // Negate the immediate or print a '-' before the operand.
498       // Note: this is a temporary solution. It should be handled target
499       // independently as part of the 'MC' work.
500       if (MO.isImm()) {
501         O << -MO.getImm();
502         return false;
503       }
504       O << '-';
505     }
506   }
507 
508   printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
509   return false;
510 }
511 
512 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
513                                           unsigned OpNo, unsigned AsmVariant,
514                                           const char *ExtraCode,
515                                           raw_ostream &O) {
516   if (AsmVariant) {
517     printIntelMemReference(*this, MI, OpNo, O);
518     return false;
519   }
520 
521   if (ExtraCode && ExtraCode[0]) {
522     if (ExtraCode[1] != 0) return true; // Unknown modifier.
523 
524     switch (ExtraCode[0]) {
525     default: return true;  // Unknown modifier.
526     case 'b': // Print QImode register
527     case 'h': // Print QImode high register
528     case 'w': // Print HImode register
529     case 'k': // Print SImode register
530     case 'q': // Print SImode register
531       // These only apply to registers, ignore on mem.
532       break;
533     case 'H':
534       printMemReference(*this, MI, OpNo, O, "H");
535       return false;
536     case 'P': // Don't print @PLT, but do print as memory.
537       printMemReference(*this, MI, OpNo, O, "no-rip");
538       return false;
539     }
540   }
541   printMemReference(*this, MI, OpNo, O);
542   return false;
543 }
544 
545 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
546   const Triple &TT = TM.getTargetTriple();
547 
548   if (TT.isOSBinFormatELF()) {
549     // Assemble feature flags that may require creation of a note section.
550     unsigned FeatureFlagsAnd = 0;
551     if (M.getModuleFlag("cf-protection-branch"))
552       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
553     if (M.getModuleFlag("cf-protection-return"))
554       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
555 
556     if (FeatureFlagsAnd) {
557       // Emit a .note.gnu.property section with the flags.
558       if (!TT.isArch32Bit() && !TT.isArch64Bit())
559         llvm_unreachable("CFProtection used on invalid architecture!");
560       MCSection *Cur = OutStreamer->getCurrentSectionOnly();
561       MCSection *Nt = MMI->getContext().getELFSection(
562           ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
563       OutStreamer->SwitchSection(Nt);
564 
565       // Emitting note header.
566       int WordSize = TT.isArch64Bit() ? 8 : 4;
567       EmitAlignment(WordSize == 4 ? 2 : 3);
568       OutStreamer->EmitIntValue(4, 4 /*size*/); // data size for "GNU\0"
569       OutStreamer->EmitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
570       OutStreamer->EmitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
571       OutStreamer->EmitBytes(StringRef("GNU", 4)); // note name
572 
573       // Emitting an Elf_Prop for the CET properties.
574       OutStreamer->EmitIntValue(ELF::GNU_PROPERTY_X86_FEATURE_1_AND, 4);
575       OutStreamer->EmitIntValue(4, 4);               // data size
576       OutStreamer->EmitIntValue(FeatureFlagsAnd, 4); // data
577       EmitAlignment(WordSize == 4 ? 2 : 3);          // padding
578 
579       OutStreamer->endSection(Nt);
580       OutStreamer->SwitchSection(Cur);
581     }
582   }
583 
584   if (TT.isOSBinFormatMachO())
585     OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
586 
587   if (TT.isOSBinFormatCOFF()) {
588     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
589     // compiler features bitfield read by link.exe.
590     MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
591     OutStreamer->BeginCOFFSymbolDef(S);
592     OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
593     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
594     OutStreamer->EndCOFFSymbolDef();
595     int64_t Feat00Flags = 0;
596 
597     if (TT.getArch() == Triple::x86) {
598       // According to the PE-COFF spec, the LSB of this value marks the object
599       // for "registered SEH".  This means that all SEH handler entry points
600       // must be registered in .sxdata.  Use of any unregistered handlers will
601       // cause the process to terminate immediately.  LLVM does not know how to
602       // register any SEH handlers, so its object files should be safe.
603       Feat00Flags |= 1;
604     }
605 
606     if (M.getModuleFlag("cfguardtable"))
607       Feat00Flags |= 0x800; // Object is CFG-aware.
608 
609     OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
610     OutStreamer->EmitAssignment(
611         S, MCConstantExpr::create(Feat00Flags, MMI->getContext()));
612   }
613   OutStreamer->EmitSyntaxDirective();
614 
615   // If this is not inline asm and we're in 16-bit
616   // mode prefix assembly with .code16.
617   bool is16 = TT.getEnvironment() == Triple::CODE16;
618   if (M.getModuleInlineAsm().empty() && is16)
619     OutStreamer->EmitAssemblerFlag(MCAF_Code16);
620 }
621 
622 static void
623 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
624                          MachineModuleInfoImpl::StubValueTy &MCSym) {
625   // L_foo$stub:
626   OutStreamer.EmitLabel(StubLabel);
627   //   .indirect_symbol _foo
628   OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
629 
630   if (MCSym.getInt())
631     // External to current translation unit.
632     OutStreamer.EmitIntValue(0, 4/*size*/);
633   else
634     // Internal to current translation unit.
635     //
636     // When we place the LSDA into the TEXT section, the type info
637     // pointers need to be indirect and pc-rel. We accomplish this by
638     // using NLPs; however, sometimes the types are local to the file.
639     // We need to fill in the value for the NLP in those cases.
640     OutStreamer.EmitValue(
641         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
642         4 /*size*/);
643 }
644 
645 static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
646 
647   MachineModuleInfoMachO &MMIMacho =
648       MMI->getObjFileInfo<MachineModuleInfoMachO>();
649 
650   // Output stubs for dynamically-linked functions.
651   MachineModuleInfoMachO::SymbolListTy Stubs;
652 
653   // Output stubs for external and common global variables.
654   Stubs = MMIMacho.GetGVStubList();
655   if (!Stubs.empty()) {
656     OutStreamer.SwitchSection(MMI->getContext().getMachOSection(
657         "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
658         SectionKind::getMetadata()));
659 
660     for (auto &Stub : Stubs)
661       emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
662 
663     Stubs.clear();
664     OutStreamer.AddBlankLine();
665   }
666 }
667 
668 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
669   const Triple &TT = TM.getTargetTriple();
670 
671   if (TT.isOSBinFormatMachO()) {
672     // Mach-O uses non-lazy symbol stubs to encode per-TU information into
673     // global table for symbol lookup.
674     emitNonLazyStubs(MMI, *OutStreamer);
675 
676     // Emit stack and fault map information.
677     emitStackMaps(SM);
678     FM.serializeToFaultMapSection();
679 
680     // This flag tells the linker that no global symbols contain code that fall
681     // through to other global symbols (e.g. an implementation of multiple entry
682     // points). If this doesn't occur, the linker can safely perform dead code
683     // stripping. Since LLVM never generates code that does this, it is always
684     // safe to set.
685     OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
686     return;
687   }
688 
689   if (TT.isKnownWindowsMSVCEnvironment() && MMI->usesVAFloatArgument()) {
690     StringRef SymbolName =
691         (TT.getArch() == Triple::x86_64) ? "_fltused" : "__fltused";
692     MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
693     OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
694     return;
695   }
696 
697   if (TT.isOSBinFormatCOFF()) {
698     emitStackMaps(SM);
699     return;
700   }
701 
702   if (TT.isOSBinFormatELF()) {
703     emitStackMaps(SM);
704     FM.serializeToFaultMapSection();
705     return;
706   }
707 }
708 
709 //===----------------------------------------------------------------------===//
710 // Target Registry Stuff
711 //===----------------------------------------------------------------------===//
712 
713 // Force static initialization.
714 extern "C" void LLVMInitializeX86AsmPrinter() {
715   RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
716   RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
717 }
718