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"
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   SMShadowTracker.startFunction(MF);
51 
52   SetupMachineFunction(MF);
53 
54   if (Subtarget->isTargetCOFF()) {
55     bool Intrn = MF.getFunction()->hasInternalLinkage();
56     OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
57     OutStreamer.EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
58                                               : COFF::IMAGE_SYM_CLASS_EXTERNAL);
59     OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
60                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
61     OutStreamer.EndCOFFSymbolDef();
62   }
63 
64   // Have common code print out the function header with linkage info etc.
65   EmitFunctionHeader();
66 
67   // Emit the rest of the function body.
68   EmitFunctionBody();
69 
70   // We didn't modify anything.
71   return false;
72 }
73 
74 /// printSymbolOperand - Print a raw symbol reference operand.  This handles
75 /// jump tables, constant pools, global address and external symbols, all of
76 /// which print to a label with various suffixes for relocation types etc.
77 static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
78                                raw_ostream &O) {
79   switch (MO.getType()) {
80   default: llvm_unreachable("unknown symbol type!");
81   case MachineOperand::MO_ConstantPoolIndex:
82     O << *P.GetCPISymbol(MO.getIndex());
83     P.printOffset(MO.getOffset(), O);
84     break;
85   case MachineOperand::MO_GlobalAddress: {
86     const GlobalValue *GV = MO.getGlobal();
87 
88     MCSymbol *GVSym;
89     if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
90       GVSym = P.getSymbolWithGlobalValueBase(GV, "$stub");
91     else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
92              MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
93              MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
94       GVSym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
95     else
96       GVSym = P.getSymbol(GV);
97 
98     // Handle dllimport linkage.
99     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
100       GVSym =
101           P.OutContext.GetOrCreateSymbol(Twine("__imp_") + GVSym->getName());
102 
103     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
104         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
105       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
106       MachineModuleInfoImpl::StubValueTy &StubSym =
107           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
108       if (!StubSym.getPointer())
109         StubSym = MachineModuleInfoImpl::
110           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
111     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
112       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
113       MachineModuleInfoImpl::StubValueTy &StubSym =
114           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(
115               Sym);
116       if (!StubSym.getPointer())
117         StubSym = MachineModuleInfoImpl::
118           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
119     } else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
120       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$stub");
121       MachineModuleInfoImpl::StubValueTy &StubSym =
122           P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
123       if (!StubSym.getPointer())
124         StubSym = MachineModuleInfoImpl::
125           StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
126     }
127 
128     // If the name begins with a dollar-sign, enclose it in parens.  We do this
129     // to avoid having it look like an integer immediate to the assembler.
130     if (GVSym->getName()[0] != '$')
131       O << *GVSym;
132     else
133       O << '(' << *GVSym << ')';
134     P.printOffset(MO.getOffset(), O);
135     break;
136   }
137   }
138 
139   switch (MO.getTargetFlags()) {
140   default:
141     llvm_unreachable("Unknown target flag on GV operand");
142   case X86II::MO_NO_FLAG:    // No flag.
143     break;
144   case X86II::MO_DARWIN_NONLAZY:
145   case X86II::MO_DLLIMPORT:
146   case X86II::MO_DARWIN_STUB:
147     // These affect the name of the symbol, not any suffix.
148     break;
149   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
150     O << " + [.-" << *P.MF->getPICBaseSymbol() << ']';
151     break;
152   case X86II::MO_PIC_BASE_OFFSET:
153   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
154   case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
155     O << '-' << *P.MF->getPICBaseSymbol();
156     break;
157   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
158   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
159   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
160   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
161   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
162   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
163   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
164   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
165   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
166   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
167   case X86II::MO_GOT:       O << "@GOT";       break;
168   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
169   case X86II::MO_PLT:       O << "@PLT";       break;
170   case X86II::MO_TLVP:      O << "@TLVP";      break;
171   case X86II::MO_TLVP_PIC_BASE:
172     O << "@TLVP" << '-' << *P.MF->getPICBaseSymbol();
173     break;
174   case X86II::MO_SECREL:    O << "@SECREL32";  break;
175   }
176 }
177 
178 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
179                          unsigned OpNo, raw_ostream &O,
180                          const char *Modifier = nullptr, unsigned AsmVariant = 0);
181 
182 /// printPCRelImm - This is used to print an immediate value that ends up
183 /// being encoded as a pc-relative value.  These print slightly differently, for
184 /// example, a $ is not emitted.
185 static void printPCRelImm(X86AsmPrinter &P, const MachineInstr *MI,
186                           unsigned OpNo, raw_ostream &O) {
187   const MachineOperand &MO = MI->getOperand(OpNo);
188   switch (MO.getType()) {
189   default: llvm_unreachable("Unknown pcrel immediate operand");
190   case MachineOperand::MO_Register:
191     // pc-relativeness was handled when computing the value in the reg.
192     printOperand(P, MI, OpNo, O);
193     return;
194   case MachineOperand::MO_Immediate:
195     O << MO.getImm();
196     return;
197   case MachineOperand::MO_GlobalAddress:
198     printSymbolOperand(P, MO, O);
199     return;
200   }
201 }
202 
203 static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
204                          unsigned OpNo, raw_ostream &O, const char *Modifier,
205                          unsigned AsmVariant) {
206   const MachineOperand &MO = MI->getOperand(OpNo);
207   switch (MO.getType()) {
208   default: llvm_unreachable("unknown operand type!");
209   case MachineOperand::MO_Register: {
210     // FIXME: Enumerating AsmVariant, so we can remove magic number.
211     if (AsmVariant == 0) O << '%';
212     unsigned Reg = MO.getReg();
213     if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
214       MVT::SimpleValueType VT = (strcmp(Modifier+6,"64") == 0) ?
215         MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
216                     ((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
217       Reg = getX86SubSuperRegister(Reg, VT);
218     }
219     O << X86ATTInstPrinter::getRegisterName(Reg);
220     return;
221   }
222 
223   case MachineOperand::MO_Immediate:
224     if (AsmVariant == 0) O << '$';
225     O << MO.getImm();
226     return;
227 
228   case MachineOperand::MO_GlobalAddress: {
229     if (AsmVariant == 0) O << '$';
230     printSymbolOperand(P, MO, O);
231     break;
232   }
233   }
234 }
235 
236 static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
237                                  unsigned Op, raw_ostream &O,
238                                  const char *Modifier = nullptr) {
239   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
240   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
241   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
242 
243   // If we really don't want to print out (rip), don't.
244   bool HasBaseReg = BaseReg.getReg() != 0;
245   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
246       BaseReg.getReg() == X86::RIP)
247     HasBaseReg = false;
248 
249   // HasParenPart - True if we will print out the () part of the mem ref.
250   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
251 
252   switch (DispSpec.getType()) {
253   default:
254     llvm_unreachable("unknown operand type!");
255   case MachineOperand::MO_Immediate: {
256     int DispVal = DispSpec.getImm();
257     if (DispVal || !HasParenPart)
258       O << DispVal;
259     break;
260   }
261   case MachineOperand::MO_GlobalAddress:
262   case MachineOperand::MO_ConstantPoolIndex:
263     printSymbolOperand(P, DispSpec, O);
264   }
265 
266   if (Modifier && strcmp(Modifier, "H") == 0)
267     O << "+8";
268 
269   if (HasParenPart) {
270     assert(IndexReg.getReg() != X86::ESP &&
271            "X86 doesn't allow scaling by ESP");
272 
273     O << '(';
274     if (HasBaseReg)
275       printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
276 
277     if (IndexReg.getReg()) {
278       O << ',';
279       printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
280       unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
281       if (ScaleVal != 1)
282         O << ',' << ScaleVal;
283     }
284     O << ')';
285   }
286 }
287 
288 static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
289                               unsigned Op, raw_ostream &O,
290                               const char *Modifier = nullptr) {
291   assert(isMem(MI, Op) && "Invalid memory reference!");
292   const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
293   if (Segment.getReg()) {
294     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
295     O << ':';
296   }
297   printLeaMemReference(P, MI, Op, O, Modifier);
298 }
299 
300 static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
301                                    unsigned Op, raw_ostream &O,
302                                    const char *Modifier = nullptr,
303                                    unsigned AsmVariant = 1) {
304   const MachineOperand &BaseReg  = MI->getOperand(Op+X86::AddrBaseReg);
305   unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
306   const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
307   const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
308   const MachineOperand &SegReg   = MI->getOperand(Op+X86::AddrSegmentReg);
309 
310   // If this has a segment register, print it.
311   if (SegReg.getReg()) {
312     printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
313     O << ':';
314   }
315 
316   O << '[';
317 
318   bool NeedPlus = false;
319   if (BaseReg.getReg()) {
320     printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
321     NeedPlus = true;
322   }
323 
324   if (IndexReg.getReg()) {
325     if (NeedPlus) O << " + ";
326     if (ScaleVal != 1)
327       O << ScaleVal << '*';
328     printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
329     NeedPlus = true;
330   }
331 
332   if (!DispSpec.isImm()) {
333     if (NeedPlus) O << " + ";
334     printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
335   } else {
336     int64_t DispVal = DispSpec.getImm();
337     if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
338       if (NeedPlus) {
339         if (DispVal > 0)
340           O << " + ";
341         else {
342           O << " - ";
343           DispVal = -DispVal;
344         }
345       }
346       O << DispVal;
347     }
348   }
349   O << ']';
350 }
351 
352 static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
353                               char Mode, raw_ostream &O) {
354   unsigned Reg = MO.getReg();
355   switch (Mode) {
356   default: return true;  // Unknown mode.
357   case 'b': // Print QImode register
358     Reg = getX86SubSuperRegister(Reg, MVT::i8);
359     break;
360   case 'h': // Print QImode high register
361     Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
362     break;
363   case 'w': // Print HImode register
364     Reg = getX86SubSuperRegister(Reg, MVT::i16);
365     break;
366   case 'k': // Print SImode register
367     Reg = getX86SubSuperRegister(Reg, MVT::i32);
368     break;
369   case 'q':
370     // Print 64-bit register names if 64-bit integer registers are available.
371     // Otherwise, print 32-bit register names.
372     MVT::SimpleValueType Ty = P.getSubtarget().is64Bit() ? MVT::i64 : MVT::i32;
373     Reg = getX86SubSuperRegister(Reg, Ty);
374     break;
375   }
376 
377   O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
378   return false;
379 }
380 
381 /// PrintAsmOperand - Print out an operand for an inline asm expression.
382 ///
383 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
384                                     unsigned AsmVariant,
385                                     const char *ExtraCode, raw_ostream &O) {
386   // Does this asm operand have a single letter operand modifier?
387   if (ExtraCode && ExtraCode[0]) {
388     if (ExtraCode[1] != 0) return true; // Unknown modifier.
389 
390     const MachineOperand &MO = MI->getOperand(OpNo);
391 
392     switch (ExtraCode[0]) {
393     default:
394       // See if this is a generic print operand
395       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
396     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
397       switch (MO.getType()) {
398       default:
399         return true;
400       case MachineOperand::MO_Immediate:
401         O << MO.getImm();
402         return false;
403       case MachineOperand::MO_ConstantPoolIndex:
404       case MachineOperand::MO_JumpTableIndex:
405       case MachineOperand::MO_ExternalSymbol:
406         llvm_unreachable("unexpected operand type!");
407       case MachineOperand::MO_GlobalAddress:
408         printSymbolOperand(*this, MO, O);
409         if (Subtarget->isPICStyleRIPRel())
410           O << "(%rip)";
411         return false;
412       case MachineOperand::MO_Register:
413         O << '(';
414         printOperand(*this, MI, OpNo, O);
415         O << ')';
416         return false;
417       }
418 
419     case 'c': // Don't print "$" before a global var name or constant.
420       switch (MO.getType()) {
421       default:
422         printOperand(*this, MI, OpNo, O);
423         break;
424       case MachineOperand::MO_Immediate:
425         O << MO.getImm();
426         break;
427       case MachineOperand::MO_ConstantPoolIndex:
428       case MachineOperand::MO_JumpTableIndex:
429       case MachineOperand::MO_ExternalSymbol:
430         llvm_unreachable("unexpected operand type!");
431       case MachineOperand::MO_GlobalAddress:
432         printSymbolOperand(*this, MO, O);
433         break;
434       }
435       return false;
436 
437     case 'A': // Print '*' before a register (it must be a register)
438       if (MO.isReg()) {
439         O << '*';
440         printOperand(*this, MI, OpNo, O);
441         return false;
442       }
443       return true;
444 
445     case 'b': // Print QImode register
446     case 'h': // Print QImode high register
447     case 'w': // Print HImode register
448     case 'k': // Print SImode register
449     case 'q': // Print DImode register
450       if (MO.isReg())
451         return printAsmMRegister(*this, MO, ExtraCode[0], O);
452       printOperand(*this, MI, OpNo, O);
453       return false;
454 
455     case 'P': // This is the operand of a call, treat specially.
456       printPCRelImm(*this, MI, OpNo, O);
457       return false;
458 
459     case 'n':  // Negate the immediate or print a '-' before the operand.
460       // Note: this is a temporary solution. It should be handled target
461       // independently as part of the 'MC' work.
462       if (MO.isImm()) {
463         O << -MO.getImm();
464         return false;
465       }
466       O << '-';
467     }
468   }
469 
470   printOperand(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
471   return false;
472 }
473 
474 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
475                                           unsigned OpNo, unsigned AsmVariant,
476                                           const char *ExtraCode,
477                                           raw_ostream &O) {
478   if (AsmVariant) {
479     printIntelMemReference(*this, MI, OpNo, O);
480     return false;
481   }
482 
483   if (ExtraCode && ExtraCode[0]) {
484     if (ExtraCode[1] != 0) return true; // Unknown modifier.
485 
486     switch (ExtraCode[0]) {
487     default: return true;  // Unknown modifier.
488     case 'b': // Print QImode register
489     case 'h': // Print QImode high register
490     case 'w': // Print HImode register
491     case 'k': // Print SImode register
492     case 'q': // Print SImode register
493       // These only apply to registers, ignore on mem.
494       break;
495     case 'H':
496       printMemReference(*this, MI, OpNo, O, "H");
497       return false;
498     case 'P': // Don't print @PLT, but do print as memory.
499       printMemReference(*this, MI, OpNo, O, "no-rip");
500       return false;
501     }
502   }
503   printMemReference(*this, MI, OpNo, O);
504   return false;
505 }
506 
507 void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
508   if (Subtarget->isTargetMacho())
509     OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
510 
511   if (Subtarget->isTargetCOFF()) {
512     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
513     // compiler features bitfield read by link.exe.
514     if (!Subtarget->is64Bit()) {
515       MCSymbol *S = MMI->getContext().GetOrCreateSymbol(StringRef("@feat.00"));
516       OutStreamer.BeginCOFFSymbolDef(S);
517       OutStreamer.EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
518       OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
519       OutStreamer.EndCOFFSymbolDef();
520       // According to the PE-COFF spec, the LSB of this value marks the object
521       // for "registered SEH".  This means that all SEH handler entry points
522       // must be registered in .sxdata.  Use of any unregistered handlers will
523       // cause the process to terminate immediately.  LLVM does not know how to
524       // register any SEH handlers, so its object files should be safe.
525       S->setAbsolute();
526       OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
527       OutStreamer.EmitAssignment(
528           S, MCConstantExpr::Create(int64_t(1), MMI->getContext()));
529     }
530   }
531 }
532 
533 static void
534 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
535                          MachineModuleInfoImpl::StubValueTy &MCSym) {
536   // L_foo$stub:
537   OutStreamer.EmitLabel(StubLabel);
538   //   .indirect_symbol _foo
539   OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
540 
541   if (MCSym.getInt())
542     // External to current translation unit.
543     OutStreamer.EmitIntValue(0, 4/*size*/);
544   else
545     // Internal to current translation unit.
546     //
547     // When we place the LSDA into the TEXT section, the type info
548     // pointers need to be indirect and pc-rel. We accomplish this by
549     // using NLPs; however, sometimes the types are local to the file.
550     // We need to fill in the value for the NLP in those cases.
551     OutStreamer.EmitValue(
552         MCSymbolRefExpr::Create(MCSym.getPointer(), OutStreamer.getContext()),
553         4 /*size*/);
554 }
555 
556 MCSymbol *X86AsmPrinter::GetCPISymbol(unsigned CPID) const {
557   if (Subtarget->isTargetKnownWindowsMSVC()) {
558     const MachineConstantPoolEntry &CPE =
559         MF->getConstantPool()->getConstants()[CPID];
560     if (!CPE.isMachineConstantPoolEntry()) {
561       SectionKind Kind =
562           CPE.getSectionKind(TM.getSubtargetImpl()->getDataLayout());
563       const Constant *C = CPE.Val.ConstVal;
564       if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>(
565             getObjFileLowering().getSectionForConstant(Kind, C))) {
566         if (MCSymbol *Sym = S->getCOMDATSymbol()) {
567           if (Sym->isUndefined())
568             OutStreamer.EmitSymbolAttribute(Sym, MCSA_Global);
569           return Sym;
570         }
571       }
572     }
573   }
574 
575   return AsmPrinter::GetCPISymbol(CPID);
576 }
577 
578 void X86AsmPrinter::GenerateExportDirective(const MCSymbol *Sym, bool IsData) {
579   SmallString<128> Directive;
580   raw_svector_ostream OS(Directive);
581   StringRef Name = Sym->getName();
582 
583   if (Subtarget->isTargetKnownWindowsMSVC())
584     OS << " /EXPORT:";
585   else
586     OS << " -export:";
587 
588   if ((Subtarget->isTargetWindowsGNU() || Subtarget->isTargetWindowsCygwin()) &&
589       (Name[0] == getDataLayout().getGlobalPrefix()))
590     Name = Name.drop_front();
591 
592   OS << Name;
593 
594   if (IsData) {
595     if (Subtarget->isTargetKnownWindowsMSVC())
596       OS << ",DATA";
597     else
598       OS << ",data";
599   }
600 
601   OS.flush();
602   OutStreamer.EmitBytes(Directive);
603 }
604 
605 void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
606   if (Subtarget->isTargetMacho()) {
607     // All darwin targets use mach-o.
608     MachineModuleInfoMachO &MMIMacho =
609       MMI->getObjFileInfo<MachineModuleInfoMachO>();
610 
611     // Output stubs for dynamically-linked functions.
612     MachineModuleInfoMachO::SymbolListTy Stubs;
613 
614     Stubs = MMIMacho.GetFnStubList();
615     if (!Stubs.empty()) {
616       const MCSection *TheSection =
617         OutContext.getMachOSection("__IMPORT", "__jump_table",
618                                    MachO::S_SYMBOL_STUBS |
619                                    MachO::S_ATTR_SELF_MODIFYING_CODE |
620                                    MachO::S_ATTR_PURE_INSTRUCTIONS,
621                                    5, SectionKind::getMetadata());
622       OutStreamer.SwitchSection(TheSection);
623 
624       for (const auto &Stub : Stubs) {
625         // L_foo$stub:
626         OutStreamer.EmitLabel(Stub.first);
627         //   .indirect_symbol _foo
628         OutStreamer.EmitSymbolAttribute(Stub.second.getPointer(),
629                                         MCSA_IndirectSymbol);
630         // hlt; hlt; hlt; hlt; hlt     hlt = 0xf4.
631         const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
632         OutStreamer.EmitBytes(StringRef(HltInsts, 5));
633       }
634 
635       Stubs.clear();
636       OutStreamer.AddBlankLine();
637     }
638 
639     // Output stubs for external and common global variables.
640     Stubs = MMIMacho.GetGVStubList();
641     if (!Stubs.empty()) {
642       const MCSection *TheSection =
643         OutContext.getMachOSection("__IMPORT", "__pointers",
644                                    MachO::S_NON_LAZY_SYMBOL_POINTERS,
645                                    SectionKind::getMetadata());
646       OutStreamer.SwitchSection(TheSection);
647 
648       for (auto &Stub : Stubs)
649         emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
650 
651       Stubs.clear();
652       OutStreamer.AddBlankLine();
653     }
654 
655     Stubs = MMIMacho.GetHiddenGVStubList();
656     if (!Stubs.empty()) {
657       const MCSection *TheSection =
658         OutContext.getMachOSection("__IMPORT", "__pointers",
659                                    MachO::S_NON_LAZY_SYMBOL_POINTERS,
660                                    SectionKind::getMetadata());
661       OutStreamer.SwitchSection(TheSection);
662 
663       for (auto &Stub : Stubs)
664         emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
665 
666       Stubs.clear();
667       OutStreamer.AddBlankLine();
668     }
669 
670     SM.serializeToStackMapSection();
671 
672     // Funny Darwin hack: This flag tells the linker that no global symbols
673     // contain code that falls through to other global symbols (e.g. the obvious
674     // implementation of multiple entry points).  If this doesn't occur, the
675     // linker can safely perform dead code stripping.  Since LLVM never
676     // generates code that does this, it is always safe to set.
677     OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
678   }
679 
680   if (Subtarget->isTargetKnownWindowsMSVC() && MMI->usesVAFloatArgument()) {
681     StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
682     MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
683     OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
684   }
685 
686   if (Subtarget->isTargetCOFF()) {
687     // Necessary for dllexport support
688     std::vector<const MCSymbol*> DLLExportedFns, DLLExportedGlobals;
689 
690     for (const auto &Function : M)
691       if (Function.hasDLLExportStorageClass())
692         DLLExportedFns.push_back(getSymbol(&Function));
693 
694     for (const auto &Global : M.globals())
695       if (Global.hasDLLExportStorageClass())
696         DLLExportedGlobals.push_back(getSymbol(&Global));
697 
698     for (const auto &Alias : M.aliases()) {
699       if (!Alias.hasDLLExportStorageClass())
700         continue;
701 
702       if (Alias.getType()->getElementType()->isFunctionTy())
703         DLLExportedFns.push_back(getSymbol(&Alias));
704       else
705         DLLExportedGlobals.push_back(getSymbol(&Alias));
706     }
707 
708     // Output linker support code for dllexported globals on windows.
709     if (!DLLExportedGlobals.empty() || !DLLExportedFns.empty()) {
710       const TargetLoweringObjectFileCOFF &TLOFCOFF =
711         static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
712 
713       OutStreamer.SwitchSection(TLOFCOFF.getDrectveSection());
714 
715       for (auto & Symbol : DLLExportedGlobals)
716         GenerateExportDirective(Symbol, /*IsData=*/true);
717       for (auto & Symbol : DLLExportedFns)
718         GenerateExportDirective(Symbol, /*IsData=*/false);
719     }
720   }
721 
722   if (Subtarget->isTargetELF()) {
723     const TargetLoweringObjectFileELF &TLOFELF =
724       static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());
725 
726     MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
727 
728     // Output stubs for external and common global variables.
729     MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
730     if (!Stubs.empty()) {
731       OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
732       const DataLayout *TD = TM.getSubtargetImpl()->getDataLayout();
733 
734       for (const auto &Stub : Stubs) {
735         OutStreamer.EmitLabel(Stub.first);
736         OutStreamer.EmitSymbolValue(Stub.second.getPointer(),
737                                     TD->getPointerSize());
738       }
739       Stubs.clear();
740     }
741 
742     SM.serializeToStackMapSection();
743   }
744 }
745 
746 //===----------------------------------------------------------------------===//
747 // Target Registry Stuff
748 //===----------------------------------------------------------------------===//
749 
750 // Force static initialization.
751 extern "C" void LLVMInitializeX86AsmPrinter() {
752   RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
753   RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
754 }
755