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/CodeGen/MachineConstantPool.h"
21 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
22 #include "llvm/CodeGen/MachineValueType.h"
23 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
24 #include "llvm/IR/DebugInfo.h"
25 #include "llvm/IR/DerivedTypes.h"
26 #include "llvm/IR/Mangler.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/IR/Type.h"
29 #include "llvm/MC/MCAsmInfo.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/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"
41 using namespace llvm;
42 
43 //===----------------------------------------------------------------------===//
44 // Primitive Helper Functions.
45 //===----------------------------------------------------------------------===//
46 
47 /// runOnMachineFunction - Emit the function body.
48 ///
49 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
50   Subtarget = &MF.getSubtarget<X86Subtarget>();
51 
52   SMShadowTracker.startFunction(MF);
53   CodeEmitter.reset(TM.getTarget().createMCCodeEmitter(
54       *MF.getSubtarget().getInstrInfo(), *MF.getSubtarget().getRegisterInfo(),
55       MF.getContext()));
56 
57   SetupMachineFunction(MF);
58 
59   if (Subtarget->isTargetCOFF()) {
60     bool Intrn = MF.getFunction()->hasInternalLinkage();
61     OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
62     OutStreamer->EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
63                                             : COFF::IMAGE_SYM_CLASS_EXTERNAL);
64     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
65                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
66     OutStreamer->EndCOFFSymbolDef();
67   }
68 
69   // Emit the rest of the function body.
70   EmitFunctionBody();
71 
72   // We didn't modify anything.
73   return false;
74 }
75 
76 /// printSymbolOperand - Print a raw symbol reference operand.  This handles
77 /// jump tables, constant pools, global address and external symbols, all of
78 /// which print to a label with various suffixes for relocation types etc.
79 static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
80                                raw_ostream &O) {
81   switch (MO.getType()) {
82   default: llvm_unreachable("unknown symbol type!");
83   case MachineOperand::MO_ConstantPoolIndex:
84     P.GetCPISymbol(MO.getIndex())->print(O, P.MAI);
85     P.printOffset(MO.getOffset(), O);
86     break;
87   case MachineOperand::MO_GlobalAddress: {
88     const GlobalValue *GV = MO.getGlobal();
89 
90     MCSymbol *GVSym;
91     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
92         MO.getTargetFlags() == X86II::MO_DARWIN_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     }
111 
112     // If the name begins with a dollar-sign, enclose it in parens.  We do this
113     // to avoid having it look like an integer immediate to the assembler.
114     if (GVSym->getName()[0] != '$')
115       GVSym->print(O, P.MAI);
116     else {
117       O << '(';
118       GVSym->print(O, P.MAI);
119       O << ')';
120     }
121     P.printOffset(MO.getOffset(), O);
122     break;
123   }
124   }
125 
126   switch (MO.getTargetFlags()) {
127   default:
128     llvm_unreachable("Unknown target flag on GV operand");
129   case X86II::MO_NO_FLAG:    // No flag.
130     break;
131   case X86II::MO_DARWIN_NONLAZY:
132   case X86II::MO_DLLIMPORT:
133     // These affect the name of the symbol, not any suffix.
134     break;
135   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
136     O << " + [.-";
137     P.MF->getPICBaseSymbol()->print(O, P.MAI);
138     O << ']';
139     break;
140   case X86II::MO_PIC_BASE_OFFSET:
141   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
142     O << '-';
143     P.MF->getPICBaseSymbol()->print(O, P.MAI);
144     break;
145   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
146   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
147   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
148   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
149   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
150   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
151   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
152   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
153   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
154   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
155   case X86II::MO_GOT:       O << "@GOT";       break;
156   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
157   case X86II::MO_PLT:       O << "@PLT";       break;
158   case X86II::MO_TLVP:      O << "@TLVP";      break;
159   case X86II::MO_TLVP_PIC_BASE:
160     O << "@TLVP" << '-';
161     P.MF->getPICBaseSymbol()->print(O, P.MAI);
162     break;
163   case X86II::MO_SECREL:    O << "@SECREL32";  break;
164   }
165 }
166 
167 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
168                          unsigned OpNo, raw_ostream &O,
169                          const char *Modifier = nullptr, unsigned AsmVariant = 0);
170 
171 /// printPCRelImm - This is used to print an immediate value that ends up
172 /// being encoded as a pc-relative value.  These print slightly differently, for
173 /// example, a $ is not emitted.
174 static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
175                           unsigned OpNo, raw_ostream &O) {
176   const MachineOperand &MO = MI->getOperand(OpNo);
177   switch (MO.getType()) {
178   default: llvm_unreachable("Unknown pcrel immediate operand");
179   case MachineOperand::MO_Register:
180     // pc-relativeness was handled when computing the value in the reg.
181     printOperand(P, MI, OpNo, O);
182     return;
183   case MachineOperand::MO_Immediate:
184     O << MO.getImm();
185     return;
186   case MachineOperand::MO_GlobalAddress:
187     printSymbolOperand(P, MO, O);
188     return;
189   }
190 }
191 
192 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
193                          unsigned OpNo, raw_ostream &O, const char *Modifier,
194                          unsigned AsmVariant) {
195   const MachineOperand &MO = MI->getOperand(OpNo);
196   switch (MO.getType()) {
197   default: llvm_unreachable("unknown operand type!");
198   case MachineOperand::MO_Register: {
199     // FIXME: Enumerating AsmVariant, so we can remove magic number.
200     if (AsmVariant == 0) O << '%';
201     unsigned Reg = MO.getReg();
202     if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
203       unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
204                       (strcmp(Modifier+6,"32") == 0) ? 32 :
205                       (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
206       Reg = getX86SubSuperRegister(Reg, Size);
207     }
208     O << X86ATTInstPrinter::getRegisterName(Reg);
209     return;
210   }
211 
212   case MachineOperand::MO_Immediate:
213     if (AsmVariant == 0) O << '$';
214     O << MO.getImm();
215     return;
216 
217   case MachineOperand::MO_GlobalAddress: {
218     if (AsmVariant == 0) O << '$';
219     printSymbolOperand(P, MO, O);
220     break;
221   }
222   }
223 }
224 
225 static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
226                                  unsigned Op, raw_ostream &O,
227                                  const char *Modifier = nullptr) {
228   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
229   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
230   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
231 
232   // If we really don't want to print out (rip), don't.
233   bool HasBaseReg = BaseReg.getReg() != 0;
234   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
235       BaseReg.getReg() == X86::RIP)
236     HasBaseReg = false;
237 
238   // HasParenPart - True if we will print out the () part of the mem ref.
239   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
240 
241   switch (DispSpec.getType()) {
242   default:
243     llvm_unreachable("unknown operand type!");
244   case MachineOperand::MO_Immediate: {
245     int DispVal = DispSpec.getImm();
246     if (DispVal || !HasParenPart)
247       O << DispVal;
248     break;
249   }
250   case MachineOperand::MO_GlobalAddress:
251   case MachineOperand::MO_ConstantPoolIndex:
252     printSymbolOperand(P, DispSpec, O);
253   }
254 
255   if (Modifier && strcmp(Modifier, "H") == 0)
256     O << "+8";
257 
258   if (HasParenPart) {
259     assert(IndexReg.getReg() != X86::ESP &&
260            "X86 doesn't allow scaling by ESP");
261 
262     O << '(';
263     if (HasBaseReg)
264       printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
265 
266     if (IndexReg.getReg()) {
267       O << ',';
268       printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
269       unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
270       if (ScaleVal != 1)
271         O << ',' << ScaleVal;
272     }
273     O << ')';
274   }
275 }
276 
277 static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
278                               unsigned Op, raw_ostream &O,
279                               const char *Modifier = nullptr) {
280   assert(isMem(MI, Op) && "Invalid memory reference!");
281   const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
282   if (Segment.getReg()) {
283     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
284     O << ':';
285   }
286   printLeaMemReference(P, MI, Op, O, Modifier);
287 }
288 
289 static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
290                                    unsigned Op, raw_ostream &O,
291                                    const char *Modifier = nullptr,
292                                    unsigned AsmVariant = 1) {
293   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
294   unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
295   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
296   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
297   const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
298 
299   // If this has a segment register, print it.
300   if (SegReg.getReg()) {
301     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
302     O << ':';
303   }
304 
305   O << '[';
306 
307   bool NeedPlus = false;
308   if (BaseReg.getReg()) {
309     printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
310     NeedPlus = true;
311   }
312 
313   if (IndexReg.getReg()) {
314     if (NeedPlus) O << " + ";
315     if (ScaleVal != 1)
316       O << ScaleVal << '*';
317     printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
318     NeedPlus = true;
319   }
320 
321   if (!DispSpec.isImm()) {
322     if (NeedPlus) O << " + ";
323     printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
324   } else {
325     int64_t DispVal = DispSpec.getImm();
326     if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
327       if (NeedPlus) {
328         if (DispVal > 0)
329           O << " + ";
330         else {
331           O << " - ";
332           DispVal = -DispVal;
333         }
334       }
335       O << DispVal;
336     }
337   }
338   O << ']';
339 }
340 
341 static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
342                               char Mode, raw_ostream &O) {
343   unsigned Reg = MO.getReg();
344   switch (Mode) {
345   default: return true;  // Unknown mode.
346   case 'b': // Print QImode register
347     Reg = getX86SubSuperRegister(Reg, 8);
348     break;
349   case 'h': // Print QImode high register
350     Reg = getX86SubSuperRegister(Reg, 8, true);
351     break;
352   case 'w': // Print HImode register
353     Reg = getX86SubSuperRegister(Reg, 16);
354     break;
355   case 'k': // Print SImode register
356     Reg = getX86SubSuperRegister(Reg, 32);
357     break;
358   case 'q':
359     // Print 64-bit register names if 64-bit integer registers are available.
360     // Otherwise, print 32-bit register names.
361     Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
362     break;
363   }
364 
365   O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
366   return false;
367 }
368 
369 /// PrintAsmOperand - Print out an operand for an inline asm expression.
370 ///
371 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
372                                     unsigned AsmVariant,
373                                     const char *ExtraCode, raw_ostream &O) {
374   // Does this asm operand have a single letter operand modifier?
375   if (ExtraCode && ExtraCode[0]) {
376     if (ExtraCode[1] != 0) return true; // Unknown modifier.
377 
378     const MachineOperand &MO = MI->getOperand(OpNo);
379 
380     switch (ExtraCode[0]) {
381     default:
382       // See if this is a generic print operand
383       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
384     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
385       switch (MO.getType()) {
386       default:
387         return true;
388       case MachineOperand::MO_Immediate:
389         O << MO.getImm();
390         return false;
391       case MachineOperand::MO_ConstantPoolIndex:
392       case MachineOperand::MO_JumpTableIndex:
393       case MachineOperand::MO_ExternalSymbol:
394         llvm_unreachable("unexpected operand type!");
395       case MachineOperand::MO_GlobalAddress:
396         printSymbolOperand(*this, MO, O);
397         if (Subtarget->isPICStyleRIPRel())
398           O << "(%rip)";
399         return false;
400       case MachineOperand::MO_Register:
401         O << '(';
402         printOperand(*this, MI, OpNo, O);
403         O << ')';
404         return false;
405       }
406 
407     case 'c': // Don't print "$" before a global var name or constant.
408       switch (MO.getType()) {
409       default:
410         printOperand(*this, MI, OpNo, O);
411         break;
412       case MachineOperand::MO_Immediate:
413         O << MO.getImm();
414         break;
415       case MachineOperand::MO_ConstantPoolIndex:
416       case MachineOperand::MO_JumpTableIndex:
417       case MachineOperand::MO_ExternalSymbol:
418         llvm_unreachable("unexpected operand type!");
419       case MachineOperand::MO_GlobalAddress:
420         printSymbolOperand(*this, MO, O);
421         break;
422       }
423       return false;
424 
425     case 'A': // Print '*' before a register (it must be a register)
426       if (MO.isReg()) {
427         O << '*';
428         printOperand(*this, MI, OpNo, O);
429         return false;
430       }
431       return true;
432 
433     case 'b': // Print QImode register
434     case 'h': // Print QImode high register
435     case 'w': // Print HImode register
436     case 'k': // Print SImode register
437     case 'q': // Print DImode register
438       if (MO.isReg())
439         return printAsmMRegister(*this, MO, ExtraCode[0], O);
440       printOperand(*this, MI, OpNo, O);
441       return false;
442 
443     case 'P': // This is the operand of a call, treat specially.
444       printPCRelImm(*this, MI, OpNo, O);
445       return false;
446 
447     case 'n':  // Negate the immediate or print a '-' before the operand.
448       // Note: this is a temporary solution. It should be handled target
449       // independently as part of the 'MC' work.
450       if (MO.isImm()) {
451         O << -MO.getImm();
452         return false;
453       }
454       O << '-';
455     }
456   }
457 
458   printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
459   return false;
460 }
461 
462 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
463                                           unsigned OpNo, unsigned AsmVariant,
464                                           const char *ExtraCode,
465                                           raw_ostream &O) {
466   if (AsmVariant) {
467     printIntelMemReference(*this, MI, OpNo, O);
468     return false;
469   }
470 
471   if (ExtraCode && ExtraCode[0]) {
472     if (ExtraCode[1] != 0) return true; // Unknown modifier.
473 
474     switch (ExtraCode[0]) {
475     default: return true;  // Unknown modifier.
476     case 'b': // Print QImode register
477     case 'h': // Print QImode high register
478     case 'w': // Print HImode register
479     case 'k': // Print SImode register
480     case 'q': // Print SImode register
481       // These only apply to registers, ignore on mem.
482       break;
483     case 'H':
484       printMemReference(*this, MI, OpNo, O, "H");
485       return false;
486     case 'P': // Don't print @PLT, but do print as memory.
487       printMemReference(*this, MI, OpNo, O, "no-rip");
488       return false;
489     }
490   }
491   printMemReference(*this, MI, OpNo, O);
492   return false;
493 }
494 
495 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
496   const Triple &TT = TM.getTargetTriple();
497 
498   if (TT.isOSBinFormatMachO())
499     OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
500 
501   if (TT.isOSBinFormatCOFF()) {
502     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
503     // compiler features bitfield read by link.exe.
504     if (TT.getArch() == Triple::x86) {
505       MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
506       OutStreamer->BeginCOFFSymbolDef(S);
507       OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
508       OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
509       OutStreamer->EndCOFFSymbolDef();
510       // According to the PE-COFF spec, the LSB of this value marks the object
511       // for "registered SEH".  This means that all SEH handler entry points
512       // must be registered in .sxdata.  Use of any unregistered handlers will
513       // cause the process to terminate immediately.  LLVM does not know how to
514       // register any SEH handlers, so its object files should be safe.
515       OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
516       OutStreamer->EmitAssignment(
517           S, MCConstantExpr::create(int64_t(1), MMI->getContext()));
518     }
519   }
520   OutStreamer->EmitSyntaxDirective();
521 
522   // If this is not inline asm and we're in 16-bit
523   // mode prefix assembly with .code16.
524   bool is16 = TT.getEnvironment() == Triple::CODE16;
525   if (M.getModuleInlineAsm().empty() && is16)
526     OutStreamer->EmitAssemblerFlag(MCAF_Code16);
527 }
528 
529 static void
530 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
531                          MachineModuleInfoImpl::StubValueTy &MCSym) {
532   // L_foo$stub:
533   OutStreamer.EmitLabel(StubLabel);
534   //   .indirect_symbol _foo
535   OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
536 
537   if (MCSym.getInt())
538     // External to current translation unit.
539     OutStreamer.EmitIntValue(0, 4/*size*/);
540   else
541     // Internal to current translation unit.
542     //
543     // When we place the LSDA into the TEXT section, the type info
544     // pointers need to be indirect and pc-rel. We accomplish this by
545     // using NLPs; however, sometimes the types are local to the file.
546     // We need to fill in the value for the NLP in those cases.
547     OutStreamer.EmitValue(
548         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
549         4 /*size*/);
550 }
551 
552 MCSymbol *X86AsmPrinter::GetCPISymbol(unsigned CPID) const {
553   if (Subtarget->isTargetKnownWindowsMSVC()) {
554     const MachineConstantPoolEntry &CPE =
555         MF->getConstantPool()->getConstants()[CPID];
556     if (!CPE.isMachineConstantPoolEntry()) {
557       const DataLayout &DL = MF->getDataLayout();
558       SectionKind Kind = CPE.getSectionKind(&DL);
559       const Constant *C = CPE.Val.ConstVal;
560       unsigned Align = CPE.Alignment;
561       if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
562               getObjFileLowering().getSectionForConstant(DL, Kind, C, Align))) {
563         if (MCSymbol *Sym = S->getCOMDATSymbol()) {
564           if (Sym->isUndefined())
565             OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global);
566           return Sym;
567         }
568       }
569     }
570   }
571 
572   return AsmPrinter::GetCPISymbol(CPID);
573 }
574 
575 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
576   const Triple &TT = TM.getTargetTriple();
577 
578   if (TT.isOSBinFormatMachO()) {
579     // All darwin targets use mach-o.
580     MachineModuleInfoMachO &MMIMacho =
581         MMI->getObjFileInfo<MachineModuleInfoMachO>();
582 
583     // Output stubs for dynamically-linked functions.
584     MachineModuleInfoMachO::SymbolListTy Stubs;
585 
586     // Output stubs for external and common global variables.
587     Stubs = MMIMacho.GetGVStubList();
588     if (!Stubs.empty()) {
589       MCSection *TheSection = OutContext.getMachOSection(
590           "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
591           SectionKind::getMetadata());
592       OutStreamer->SwitchSection(TheSection);
593 
594       for (auto &Stub : Stubs)
595         emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
596 
597       Stubs.clear();
598       OutStreamer->AddBlankLine();
599     }
600 
601     SM.serializeToStackMapSection();
602     FM.serializeToFaultMapSection();
603 
604     // Funny Darwin hack: This flag tells the linker that no global symbols
605     // contain code that falls through to other global symbols (e.g. the obvious
606     // implementation of multiple entry points).  If this doesn't occur, the
607     // linker can safely perform dead code stripping.  Since LLVM never
608     // generates code that does this, it is always safe to set.
609     OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
610   }
611 
612   if (TT.isKnownWindowsMSVCEnvironment() && MMI->usesVAFloatArgument()) {
613     StringRef SymbolName =
614         (TT.getArch() == Triple::x86_64) ? "_fltused" : "__fltused";
615     MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
616     OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
617   }
618 
619   if (TT.isOSBinFormatCOFF()) {
620     const TargetLoweringObjectFileCOFF &TLOFCOFF =
621         static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
622 
623     std::string Flags;
624     raw_string_ostream FlagsOS(Flags);
625 
626     for (const auto &Function : M)
627       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Function, *Mang);
628     for (const auto &Global : M.globals())
629       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Global, *Mang);
630     for (const auto &Alias : M.aliases())
631       TLOFCOFF.emitLinkerFlagsForGlobal(FlagsOS, &Alias, *Mang);
632 
633     FlagsOS.flush();
634 
635     // Output collected flags.
636     if (!Flags.empty()) {
637       OutStreamer->SwitchSection(TLOFCOFF.getDrectveSection());
638       OutStreamer->EmitBytes(Flags);
639     }
640 
641     SM.serializeToStackMapSection();
642   }
643 
644   if (TT.isOSBinFormatELF()) {
645     SM.serializeToStackMapSection();
646     FM.serializeToFaultMapSection();
647   }
648 }
649 
650 //===----------------------------------------------------------------------===//
651 // Target Registry Stuff
652 //===----------------------------------------------------------------------===//
653 
654 // Force static initialization.
655 extern "C" void LLVMInitializeX86AsmPrinter() {
656   RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
657   RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
658 }
659