1 //===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains a printer that converts from our internal representation
10 // of machine-dependent LLVM code to X86 machine code.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "X86AsmPrinter.h"
15 #include "MCTargetDesc/X86ATTInstPrinter.h"
16 #include "MCTargetDesc/X86BaseInfo.h"
17 #include "MCTargetDesc/X86TargetStreamer.h"
18 #include "TargetInfo/X86TargetInfo.h"
19 #include "X86InstrInfo.h"
20 #include "X86MachineFunctionInfo.h"
21 #include "X86Subtarget.h"
22 #include "llvm/BinaryFormat/COFF.h"
23 #include "llvm/BinaryFormat/ELF.h"
24 #include "llvm/CodeGen/MachineConstantPool.h"
25 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
26 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
27 #include "llvm/IR/DerivedTypes.h"
28 #include "llvm/IR/InlineAsm.h"
29 #include "llvm/IR/Mangler.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/IR/Type.h"
32 #include "llvm/MC/MCCodeEmitter.h"
33 #include "llvm/MC/MCContext.h"
34 #include "llvm/MC/MCExpr.h"
35 #include "llvm/MC/MCSectionCOFF.h"
36 #include "llvm/MC/MCSectionELF.h"
37 #include "llvm/MC/MCSectionMachO.h"
38 #include "llvm/MC/MCStreamer.h"
39 #include "llvm/MC/MCSymbol.h"
40 #include "llvm/MC/TargetRegistry.h"
41 #include "llvm/Support/Debug.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/MachineValueType.h"
44 #include "llvm/Target/TargetMachine.h"
45 
46 using namespace llvm;
47 
48 X86AsmPrinter::X86AsmPrinter(TargetMachine &TM,
49                              std::unique_ptr<MCStreamer> Streamer)
50     : AsmPrinter(TM, std::move(Streamer)), SM(*this), FM(*this) {}
51 
52 //===----------------------------------------------------------------------===//
53 // Primitive Helper Functions.
54 //===----------------------------------------------------------------------===//
55 
56 /// runOnMachineFunction - Emit the function body.
57 ///
58 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
59   Subtarget = &MF.getSubtarget<X86Subtarget>();
60 
61   SMShadowTracker.startFunction(MF);
62   CodeEmitter.reset(TM.getTarget().createMCCodeEmitter(
63       *Subtarget->getInstrInfo(), MF.getContext()));
64 
65   EmitFPOData =
66       Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag();
67 
68   SetupMachineFunction(MF);
69 
70   if (Subtarget->isTargetCOFF()) {
71     bool Local = MF.getFunction().hasLocalLinkage();
72     OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
73     OutStreamer->EmitCOFFSymbolStorageClass(
74         Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL);
75     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
76                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
77     OutStreamer->EndCOFFSymbolDef();
78   }
79 
80   // Emit the rest of the function body.
81   emitFunctionBody();
82 
83   // Emit the XRay table for this function.
84   emitXRayTable();
85 
86   EmitFPOData = false;
87 
88   // We didn't modify anything.
89   return false;
90 }
91 
92 void X86AsmPrinter::emitFunctionBodyStart() {
93   if (EmitFPOData) {
94     if (auto *XTS =
95         static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
96       XTS->emitFPOProc(
97           CurrentFnSym,
98           MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize());
99   }
100 }
101 
102 void X86AsmPrinter::emitFunctionBodyEnd() {
103   if (EmitFPOData) {
104     if (auto *XTS =
105             static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
106       XTS->emitFPOEndProc();
107   }
108 }
109 
110 /// PrintSymbolOperand - Print a raw symbol reference operand.  This handles
111 /// jump tables, constant pools, global address and external symbols, all of
112 /// which print to a label with various suffixes for relocation types etc.
113 void X86AsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
114                                        raw_ostream &O) {
115   switch (MO.getType()) {
116   default: llvm_unreachable("unknown symbol type!");
117   case MachineOperand::MO_ConstantPoolIndex:
118     GetCPISymbol(MO.getIndex())->print(O, MAI);
119     printOffset(MO.getOffset(), O);
120     break;
121   case MachineOperand::MO_GlobalAddress: {
122     const GlobalValue *GV = MO.getGlobal();
123 
124     MCSymbol *GVSym;
125     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
126         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE)
127       GVSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
128     else
129       GVSym = getSymbolPreferLocal(*GV);
130 
131     // Handle dllimport linkage.
132     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
133       GVSym = OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
134     else if (MO.getTargetFlags() == X86II::MO_COFFSTUB)
135       GVSym =
136           OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName());
137 
138     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
139         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
140       MCSymbol *Sym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
141       MachineModuleInfoImpl::StubValueTy &StubSym =
142           MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
143       if (!StubSym.getPointer())
144         StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV),
145                                                      !GV->hasInternalLinkage());
146     }
147 
148     // If the name begins with a dollar-sign, enclose it in parens.  We do this
149     // to avoid having it look like an integer immediate to the assembler.
150     if (GVSym->getName()[0] != '$')
151       GVSym->print(O, MAI);
152     else {
153       O << '(';
154       GVSym->print(O, MAI);
155       O << ')';
156     }
157     printOffset(MO.getOffset(), O);
158     break;
159   }
160   }
161 
162   switch (MO.getTargetFlags()) {
163   default:
164     llvm_unreachable("Unknown target flag on GV operand");
165   case X86II::MO_NO_FLAG:    // No flag.
166     break;
167   case X86II::MO_DARWIN_NONLAZY:
168   case X86II::MO_DLLIMPORT:
169   case X86II::MO_COFFSTUB:
170     // These affect the name of the symbol, not any suffix.
171     break;
172   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
173     O << " + [.-";
174     MF->getPICBaseSymbol()->print(O, MAI);
175     O << ']';
176     break;
177   case X86II::MO_PIC_BASE_OFFSET:
178   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
179     O << '-';
180     MF->getPICBaseSymbol()->print(O, MAI);
181     break;
182   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
183   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
184   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
185   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
186   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
187   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
188   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
189   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
190   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
191   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
192   case X86II::MO_GOTPCREL_NORELAX: O << "@GOTPCREL_NORELAX"; break;
193   case X86II::MO_GOT:       O << "@GOT";       break;
194   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
195   case X86II::MO_PLT:       O << "@PLT";       break;
196   case X86II::MO_TLVP:      O << "@TLVP";      break;
197   case X86II::MO_TLVP_PIC_BASE:
198     O << "@TLVP" << '-';
199     MF->getPICBaseSymbol()->print(O, MAI);
200     break;
201   case X86II::MO_SECREL:    O << "@SECREL32";  break;
202   }
203 }
204 
205 void X86AsmPrinter::PrintOperand(const MachineInstr *MI, unsigned OpNo,
206                                  raw_ostream &O) {
207   const MachineOperand &MO = MI->getOperand(OpNo);
208   const bool IsATT = MI->getInlineAsmDialect() == InlineAsm::AD_ATT;
209   switch (MO.getType()) {
210   default: llvm_unreachable("unknown operand type!");
211   case MachineOperand::MO_Register: {
212     if (IsATT)
213       O << '%';
214     O << X86ATTInstPrinter::getRegisterName(MO.getReg());
215     return;
216   }
217 
218   case MachineOperand::MO_Immediate:
219     if (IsATT)
220       O << '$';
221     O << MO.getImm();
222     return;
223 
224   case MachineOperand::MO_ConstantPoolIndex:
225   case MachineOperand::MO_GlobalAddress: {
226     switch (MI->getInlineAsmDialect()) {
227     case InlineAsm::AD_ATT:
228       O << '$';
229       break;
230     case InlineAsm::AD_Intel:
231       O << "offset ";
232       break;
233     }
234     PrintSymbolOperand(MO, O);
235     break;
236   }
237   case MachineOperand::MO_BlockAddress: {
238     MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress());
239     Sym->print(O, MAI);
240     break;
241   }
242   }
243 }
244 
245 /// PrintModifiedOperand - Print subregisters based on supplied modifier,
246 /// deferring to PrintOperand() if no modifier was supplied or if operand is not
247 /// a register.
248 void X86AsmPrinter::PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo,
249                                          raw_ostream &O, const char *Modifier) {
250   const MachineOperand &MO = MI->getOperand(OpNo);
251   if (!Modifier || MO.getType() != MachineOperand::MO_Register)
252     return PrintOperand(MI, OpNo, O);
253   if (MI->getInlineAsmDialect() == InlineAsm::AD_ATT)
254     O << '%';
255   Register Reg = MO.getReg();
256   if (strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
257     unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
258         (strcmp(Modifier+6,"32") == 0) ? 32 :
259         (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
260     Reg = getX86SubSuperRegister(Reg, Size);
261   }
262   O << X86ATTInstPrinter::getRegisterName(Reg);
263 }
264 
265 /// PrintPCRelImm - This is used to print an immediate value that ends up
266 /// being encoded as a pc-relative value.  These print slightly differently, for
267 /// example, a $ is not emitted.
268 void X86AsmPrinter::PrintPCRelImm(const MachineInstr *MI, unsigned OpNo,
269                                   raw_ostream &O) {
270   const MachineOperand &MO = MI->getOperand(OpNo);
271   switch (MO.getType()) {
272   default: llvm_unreachable("Unknown pcrel immediate operand");
273   case MachineOperand::MO_Register:
274     // pc-relativeness was handled when computing the value in the reg.
275     PrintOperand(MI, OpNo, O);
276     return;
277   case MachineOperand::MO_Immediate:
278     O << MO.getImm();
279     return;
280   case MachineOperand::MO_GlobalAddress:
281     PrintSymbolOperand(MO, O);
282     return;
283   }
284 }
285 
286 void X86AsmPrinter::PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo,
287                                          raw_ostream &O, const char *Modifier) {
288   const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
289   const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
290   const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
291 
292   // If we really don't want to print out (rip), don't.
293   bool HasBaseReg = BaseReg.getReg() != 0;
294   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
295       BaseReg.getReg() == X86::RIP)
296     HasBaseReg = false;
297 
298   // HasParenPart - True if we will print out the () part of the mem ref.
299   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
300 
301   switch (DispSpec.getType()) {
302   default:
303     llvm_unreachable("unknown operand type!");
304   case MachineOperand::MO_Immediate: {
305     int DispVal = DispSpec.getImm();
306     if (DispVal || !HasParenPart)
307       O << DispVal;
308     break;
309   }
310   case MachineOperand::MO_GlobalAddress:
311   case MachineOperand::MO_ConstantPoolIndex:
312     PrintSymbolOperand(DispSpec, O);
313     break;
314   }
315 
316   if (Modifier && strcmp(Modifier, "H") == 0)
317     O << "+8";
318 
319   if (HasParenPart) {
320     assert(IndexReg.getReg() != X86::ESP &&
321            "X86 doesn't allow scaling by ESP");
322 
323     O << '(';
324     if (HasBaseReg)
325       PrintModifiedOperand(MI, OpNo + X86::AddrBaseReg, O, Modifier);
326 
327     if (IndexReg.getReg()) {
328       O << ',';
329       PrintModifiedOperand(MI, OpNo + X86::AddrIndexReg, O, Modifier);
330       unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
331       if (ScaleVal != 1)
332         O << ',' << ScaleVal;
333     }
334     O << ')';
335   }
336 }
337 
338 void X86AsmPrinter::PrintMemReference(const MachineInstr *MI, unsigned OpNo,
339                                       raw_ostream &O, const char *Modifier) {
340   assert(isMem(*MI, OpNo) && "Invalid memory reference!");
341   const MachineOperand &Segment = MI->getOperand(OpNo + X86::AddrSegmentReg);
342   if (Segment.getReg()) {
343     PrintModifiedOperand(MI, OpNo + X86::AddrSegmentReg, O, Modifier);
344     O << ':';
345   }
346   PrintLeaMemReference(MI, OpNo, O, Modifier);
347 }
348 
349 
350 void X86AsmPrinter::PrintIntelMemReference(const MachineInstr *MI,
351                                            unsigned OpNo, raw_ostream &O,
352                                            const char *Modifier) {
353   const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
354   unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
355   const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
356   const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
357   const MachineOperand &SegReg = MI->getOperand(OpNo + X86::AddrSegmentReg);
358 
359   // If we really don't want to print out (rip), don't.
360   bool HasBaseReg = BaseReg.getReg() != 0;
361   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
362       BaseReg.getReg() == X86::RIP)
363     HasBaseReg = false;
364 
365   // If we really just want to print out displacement.
366   if (Modifier && (DispSpec.isGlobal() || DispSpec.isSymbol()) &&
367       !strcmp(Modifier, "disp-only")) {
368     HasBaseReg = false;
369   }
370 
371   // If this has a segment register, print it.
372   if (SegReg.getReg()) {
373     PrintOperand(MI, OpNo + X86::AddrSegmentReg, O);
374     O << ':';
375   }
376 
377   O << '[';
378 
379   bool NeedPlus = false;
380   if (HasBaseReg) {
381     PrintOperand(MI, OpNo + X86::AddrBaseReg, O);
382     NeedPlus = true;
383   }
384 
385   if (IndexReg.getReg()) {
386     if (NeedPlus) O << " + ";
387     if (ScaleVal != 1)
388       O << ScaleVal << '*';
389     PrintOperand(MI, OpNo + X86::AddrIndexReg, O);
390     NeedPlus = true;
391   }
392 
393   if (!DispSpec.isImm()) {
394     if (NeedPlus) O << " + ";
395     PrintOperand(MI, OpNo + X86::AddrDisp, O);
396   } else {
397     int64_t DispVal = DispSpec.getImm();
398     if (DispVal || (!IndexReg.getReg() && !HasBaseReg)) {
399       if (NeedPlus) {
400         if (DispVal > 0)
401           O << " + ";
402         else {
403           O << " - ";
404           DispVal = -DispVal;
405         }
406       }
407       O << DispVal;
408     }
409   }
410   O << ']';
411 }
412 
413 static bool printAsmMRegister(const X86AsmPrinter &P, const MachineOperand &MO,
414                               char Mode, raw_ostream &O) {
415   Register Reg = MO.getReg();
416   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
417 
418   if (!X86::GR8RegClass.contains(Reg) &&
419       !X86::GR16RegClass.contains(Reg) &&
420       !X86::GR32RegClass.contains(Reg) &&
421       !X86::GR64RegClass.contains(Reg))
422     return true;
423 
424   switch (Mode) {
425   default: return true;  // Unknown mode.
426   case 'b': // Print QImode register
427     Reg = getX86SubSuperRegister(Reg, 8);
428     break;
429   case 'h': // Print QImode high register
430     Reg = getX86SubSuperRegister(Reg, 8, true);
431     break;
432   case 'w': // Print HImode register
433     Reg = getX86SubSuperRegister(Reg, 16);
434     break;
435   case 'k': // Print SImode register
436     Reg = getX86SubSuperRegister(Reg, 32);
437     break;
438   case 'V':
439     EmitPercent = false;
440     LLVM_FALLTHROUGH;
441   case 'q':
442     // Print 64-bit register names if 64-bit integer registers are available.
443     // Otherwise, print 32-bit register names.
444     Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
445     break;
446   }
447 
448   if (EmitPercent)
449     O << '%';
450 
451   O << X86ATTInstPrinter::getRegisterName(Reg);
452   return false;
453 }
454 
455 static bool printAsmVRegister(const MachineOperand &MO, char Mode,
456                               raw_ostream &O) {
457   Register Reg = MO.getReg();
458   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
459 
460   unsigned Index;
461   if (X86::VR128XRegClass.contains(Reg))
462     Index = Reg - X86::XMM0;
463   else if (X86::VR256XRegClass.contains(Reg))
464     Index = Reg - X86::YMM0;
465   else if (X86::VR512RegClass.contains(Reg))
466     Index = Reg - X86::ZMM0;
467   else
468     return true;
469 
470   switch (Mode) {
471   default: // Unknown mode.
472     return true;
473   case 'x': // Print V4SFmode register
474     Reg = X86::XMM0 + Index;
475     break;
476   case 't': // Print V8SFmode register
477     Reg = X86::YMM0 + Index;
478     break;
479   case 'g': // Print V16SFmode register
480     Reg = X86::ZMM0 + Index;
481     break;
482   }
483 
484   if (EmitPercent)
485     O << '%';
486 
487   O << X86ATTInstPrinter::getRegisterName(Reg);
488   return false;
489 }
490 
491 /// PrintAsmOperand - Print out an operand for an inline asm expression.
492 ///
493 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
494                                     const char *ExtraCode, raw_ostream &O) {
495   // Does this asm operand have a single letter operand modifier?
496   if (ExtraCode && ExtraCode[0]) {
497     if (ExtraCode[1] != 0) return true; // Unknown modifier.
498 
499     const MachineOperand &MO = MI->getOperand(OpNo);
500 
501     switch (ExtraCode[0]) {
502     default:
503       // See if this is a generic print operand
504       return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
505     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
506       switch (MO.getType()) {
507       default:
508         return true;
509       case MachineOperand::MO_Immediate:
510         O << MO.getImm();
511         return false;
512       case MachineOperand::MO_ConstantPoolIndex:
513       case MachineOperand::MO_JumpTableIndex:
514       case MachineOperand::MO_ExternalSymbol:
515         llvm_unreachable("unexpected operand type!");
516       case MachineOperand::MO_GlobalAddress:
517         PrintSymbolOperand(MO, O);
518         if (Subtarget->isPICStyleRIPRel())
519           O << "(%rip)";
520         return false;
521       case MachineOperand::MO_Register:
522         O << '(';
523         PrintOperand(MI, OpNo, O);
524         O << ')';
525         return false;
526       }
527 
528     case 'c': // Don't print "$" before a global var name or constant.
529       switch (MO.getType()) {
530       default:
531         PrintOperand(MI, OpNo, O);
532         break;
533       case MachineOperand::MO_Immediate:
534         O << MO.getImm();
535         break;
536       case MachineOperand::MO_ConstantPoolIndex:
537       case MachineOperand::MO_JumpTableIndex:
538       case MachineOperand::MO_ExternalSymbol:
539         llvm_unreachable("unexpected operand type!");
540       case MachineOperand::MO_GlobalAddress:
541         PrintSymbolOperand(MO, O);
542         break;
543       }
544       return false;
545 
546     case 'A': // Print '*' before a register (it must be a register)
547       if (MO.isReg()) {
548         O << '*';
549         PrintOperand(MI, OpNo, O);
550         return false;
551       }
552       return true;
553 
554     case 'b': // Print QImode register
555     case 'h': // Print QImode high register
556     case 'w': // Print HImode register
557     case 'k': // Print SImode register
558     case 'q': // Print DImode register
559     case 'V': // Print native register without '%'
560       if (MO.isReg())
561         return printAsmMRegister(*this, MO, ExtraCode[0], O);
562       PrintOperand(MI, OpNo, O);
563       return false;
564 
565     case 'x': // Print V4SFmode register
566     case 't': // Print V8SFmode register
567     case 'g': // Print V16SFmode register
568       if (MO.isReg())
569         return printAsmVRegister(MO, ExtraCode[0], O);
570       PrintOperand(MI, OpNo, O);
571       return false;
572 
573     case 'P': // This is the operand of a call, treat specially.
574       PrintPCRelImm(MI, OpNo, O);
575       return false;
576 
577     case 'n': // Negate the immediate or print a '-' before the operand.
578       // Note: this is a temporary solution. It should be handled target
579       // independently as part of the 'MC' work.
580       if (MO.isImm()) {
581         O << -MO.getImm();
582         return false;
583       }
584       O << '-';
585     }
586   }
587 
588   PrintOperand(MI, OpNo, O);
589   return false;
590 }
591 
592 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
593                                           const char *ExtraCode,
594                                           raw_ostream &O) {
595   if (ExtraCode && ExtraCode[0]) {
596     if (ExtraCode[1] != 0) return true; // Unknown modifier.
597 
598     switch (ExtraCode[0]) {
599     default: return true;  // Unknown modifier.
600     case 'b': // Print QImode register
601     case 'h': // Print QImode high register
602     case 'w': // Print HImode register
603     case 'k': // Print SImode register
604     case 'q': // Print SImode register
605       // These only apply to registers, ignore on mem.
606       break;
607     case 'H':
608       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
609         return true;  // Unsupported modifier in Intel inline assembly.
610       } else {
611         PrintMemReference(MI, OpNo, O, "H");
612       }
613       return false;
614    // Print memory only with displacement. The Modifer 'P' is used in inline
615    // asm to present a call symbol or a global symbol which can not use base
616    // reg or index reg.
617     case 'P':
618       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
619         PrintIntelMemReference(MI, OpNo, O, "disp-only");
620       } else {
621         PrintMemReference(MI, OpNo, O, "disp-only");
622       }
623       return false;
624     }
625   }
626   if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
627     PrintIntelMemReference(MI, OpNo, O, nullptr);
628   } else {
629     PrintMemReference(MI, OpNo, O, nullptr);
630   }
631   return false;
632 }
633 
634 void X86AsmPrinter::emitStartOfAsmFile(Module &M) {
635   const Triple &TT = TM.getTargetTriple();
636 
637   if (TT.isOSBinFormatELF()) {
638     // Assemble feature flags that may require creation of a note section.
639     unsigned FeatureFlagsAnd = 0;
640     if (M.getModuleFlag("cf-protection-branch"))
641       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
642     if (M.getModuleFlag("cf-protection-return"))
643       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
644 
645     if (FeatureFlagsAnd) {
646       // Emit a .note.gnu.property section with the flags.
647       if (!TT.isArch32Bit() && !TT.isArch64Bit())
648         llvm_unreachable("CFProtection used on invalid architecture!");
649       MCSection *Cur = OutStreamer->getCurrentSectionOnly();
650       MCSection *Nt = MMI->getContext().getELFSection(
651           ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
652       OutStreamer->SwitchSection(Nt);
653 
654       // Emitting note header.
655       const int WordSize = TT.isArch64Bit() && !TT.isX32() ? 8 : 4;
656       emitAlignment(WordSize == 4 ? Align(4) : Align(8));
657       OutStreamer->emitIntValue(4, 4 /*size*/); // data size for "GNU\0"
658       OutStreamer->emitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
659       OutStreamer->emitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
660       OutStreamer->emitBytes(StringRef("GNU", 4)); // note name
661 
662       // Emitting an Elf_Prop for the CET properties.
663       OutStreamer->emitInt32(ELF::GNU_PROPERTY_X86_FEATURE_1_AND);
664       OutStreamer->emitInt32(4);                          // data size
665       OutStreamer->emitInt32(FeatureFlagsAnd);            // data
666       emitAlignment(WordSize == 4 ? Align(4) : Align(8)); // padding
667 
668       OutStreamer->endSection(Nt);
669       OutStreamer->SwitchSection(Cur);
670     }
671   }
672 
673   if (TT.isOSBinFormatMachO())
674     OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
675 
676   if (TT.isOSBinFormatCOFF()) {
677     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
678     // compiler features bitfield read by link.exe.
679     MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
680     OutStreamer->BeginCOFFSymbolDef(S);
681     OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
682     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
683     OutStreamer->EndCOFFSymbolDef();
684     int64_t Feat00Flags = 0;
685 
686     if (TT.getArch() == Triple::x86) {
687       // According to the PE-COFF spec, the LSB of this value marks the object
688       // for "registered SEH".  This means that all SEH handler entry points
689       // must be registered in .sxdata.  Use of any unregistered handlers will
690       // cause the process to terminate immediately.  LLVM does not know how to
691       // register any SEH handlers, so its object files should be safe.
692       Feat00Flags |= 1;
693     }
694 
695     if (M.getModuleFlag("cfguard")) {
696       Feat00Flags |= 0x800; // Object is CFG-aware.
697     }
698 
699     if (M.getModuleFlag("ehcontguard")) {
700       Feat00Flags |= 0x4000; // Object also has EHCont.
701     }
702 
703     OutStreamer->emitSymbolAttribute(S, MCSA_Global);
704     OutStreamer->emitAssignment(
705         S, MCConstantExpr::create(Feat00Flags, MMI->getContext()));
706   }
707   OutStreamer->emitSyntaxDirective();
708 
709   // If this is not inline asm and we're in 16-bit
710   // mode prefix assembly with .code16.
711   bool is16 = TT.getEnvironment() == Triple::CODE16;
712   if (M.getModuleInlineAsm().empty() && is16)
713     OutStreamer->emitAssemblerFlag(MCAF_Code16);
714 }
715 
716 static void
717 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
718                          MachineModuleInfoImpl::StubValueTy &MCSym) {
719   // L_foo$stub:
720   OutStreamer.emitLabel(StubLabel);
721   //   .indirect_symbol _foo
722   OutStreamer.emitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
723 
724   if (MCSym.getInt())
725     // External to current translation unit.
726     OutStreamer.emitIntValue(0, 4/*size*/);
727   else
728     // Internal to current translation unit.
729     //
730     // When we place the LSDA into the TEXT section, the type info
731     // pointers need to be indirect and pc-rel. We accomplish this by
732     // using NLPs; however, sometimes the types are local to the file.
733     // We need to fill in the value for the NLP in those cases.
734     OutStreamer.emitValue(
735         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
736         4 /*size*/);
737 }
738 
739 static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
740 
741   MachineModuleInfoMachO &MMIMacho =
742       MMI->getObjFileInfo<MachineModuleInfoMachO>();
743 
744   // Output stubs for dynamically-linked functions.
745   MachineModuleInfoMachO::SymbolListTy Stubs;
746 
747   // Output stubs for external and common global variables.
748   Stubs = MMIMacho.GetGVStubList();
749   if (!Stubs.empty()) {
750     OutStreamer.SwitchSection(MMI->getContext().getMachOSection(
751         "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
752         SectionKind::getMetadata()));
753 
754     for (auto &Stub : Stubs)
755       emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
756 
757     Stubs.clear();
758     OutStreamer.AddBlankLine();
759   }
760 }
761 
762 void X86AsmPrinter::emitEndOfAsmFile(Module &M) {
763   const Triple &TT = TM.getTargetTriple();
764 
765   if (TT.isOSBinFormatMachO()) {
766     // Mach-O uses non-lazy symbol stubs to encode per-TU information into
767     // global table for symbol lookup.
768     emitNonLazyStubs(MMI, *OutStreamer);
769 
770     // Emit stack and fault map information.
771     emitStackMaps(SM);
772     FM.serializeToFaultMapSection();
773 
774     // This flag tells the linker that no global symbols contain code that fall
775     // through to other global symbols (e.g. an implementation of multiple entry
776     // points). If this doesn't occur, the linker can safely perform dead code
777     // stripping. Since LLVM never generates code that does this, it is always
778     // safe to set.
779     OutStreamer->emitAssemblerFlag(MCAF_SubsectionsViaSymbols);
780   } else if (TT.isOSBinFormatCOFF()) {
781     if (MMI->usesMSVCFloatingPoint()) {
782       // In Windows' libcmt.lib, there is a file which is linked in only if the
783       // symbol _fltused is referenced. Linking this in causes some
784       // side-effects:
785       //
786       // 1. For x86-32, it will set the x87 rounding mode to 53-bit instead of
787       // 64-bit mantissas at program start.
788       //
789       // 2. It links in support routines for floating-point in scanf and printf.
790       //
791       // MSVC emits an undefined reference to _fltused when there are any
792       // floating point operations in the program (including calls). A program
793       // that only has: `scanf("%f", &global_float);` may fail to trigger this,
794       // but oh well...that's a documented issue.
795       StringRef SymbolName =
796           (TT.getArch() == Triple::x86) ? "__fltused" : "_fltused";
797       MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
798       OutStreamer->emitSymbolAttribute(S, MCSA_Global);
799       return;
800     }
801     emitStackMaps(SM);
802   } else if (TT.isOSBinFormatELF()) {
803     emitStackMaps(SM);
804     FM.serializeToFaultMapSection();
805   }
806 }
807 
808 //===----------------------------------------------------------------------===//
809 // Target Registry Stuff
810 //===----------------------------------------------------------------------===//
811 
812 // Force static initialization.
813 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86AsmPrinter() {
814   RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
815   RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
816 }
817