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/Support/Debug.h"
41 #include "llvm/Support/ErrorHandling.h"
42 #include "llvm/Support/MachineValueType.h"
43 #include "llvm/Support/TargetRegistry.h"
44 #include "llvm/Target/TargetMachine.h"
45 
46 using namespace llvm;
47 
X86AsmPrinter(TargetMachine & TM,std::unique_ptr<MCStreamer> Streamer)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 ///
runOnMachineFunction(MachineFunction & MF)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(), *Subtarget->getRegisterInfo(),
64       MF.getContext()));
65 
66   EmitFPOData =
67       Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag();
68 
69   SetupMachineFunction(MF);
70 
71   if (Subtarget->isTargetCOFF()) {
72     bool Local = MF.getFunction().hasLocalLinkage();
73     OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
74     OutStreamer->EmitCOFFSymbolStorageClass(
75         Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL);
76     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
77                                                << COFF::SCT_COMPLEX_TYPE_SHIFT);
78     OutStreamer->EndCOFFSymbolDef();
79   }
80 
81   // Emit the rest of the function body.
82   emitFunctionBody();
83 
84   // Emit the XRay table for this function.
85   emitXRayTable();
86 
87   EmitFPOData = false;
88 
89   // We didn't modify anything.
90   return false;
91 }
92 
emitFunctionBodyStart()93 void X86AsmPrinter::emitFunctionBodyStart() {
94   if (EmitFPOData) {
95     if (auto *XTS =
96         static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
97       XTS->emitFPOProc(
98           CurrentFnSym,
99           MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize());
100   }
101 }
102 
emitFunctionBodyEnd()103 void X86AsmPrinter::emitFunctionBodyEnd() {
104   if (EmitFPOData) {
105     if (auto *XTS =
106             static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
107       XTS->emitFPOEndProc();
108   }
109 }
110 
111 /// PrintSymbolOperand - Print a raw symbol reference operand.  This handles
112 /// jump tables, constant pools, global address and external symbols, all of
113 /// which print to a label with various suffixes for relocation types etc.
PrintSymbolOperand(const MachineOperand & MO,raw_ostream & O)114 void X86AsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
115                                        raw_ostream &O) {
116   switch (MO.getType()) {
117   default: llvm_unreachable("unknown symbol type!");
118   case MachineOperand::MO_ConstantPoolIndex:
119     GetCPISymbol(MO.getIndex())->print(O, MAI);
120     printOffset(MO.getOffset(), O);
121     break;
122   case MachineOperand::MO_GlobalAddress: {
123     const GlobalValue *GV = MO.getGlobal();
124 
125     MCSymbol *GVSym;
126     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
127         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE)
128       GVSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
129     else
130       GVSym = getSymbolPreferLocal(*GV);
131 
132     // Handle dllimport linkage.
133     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
134       GVSym = OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
135     else if (MO.getTargetFlags() == X86II::MO_COFFSTUB)
136       GVSym =
137           OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName());
138 
139     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
140         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
141       MCSymbol *Sym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
142       MachineModuleInfoImpl::StubValueTy &StubSym =
143           MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
144       if (!StubSym.getPointer())
145         StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV),
146                                                      !GV->hasInternalLinkage());
147     }
148 
149     // If the name begins with a dollar-sign, enclose it in parens.  We do this
150     // to avoid having it look like an integer immediate to the assembler.
151     if (GVSym->getName()[0] != '$')
152       GVSym->print(O, MAI);
153     else {
154       O << '(';
155       GVSym->print(O, MAI);
156       O << ')';
157     }
158     printOffset(MO.getOffset(), O);
159     break;
160   }
161   }
162 
163   switch (MO.getTargetFlags()) {
164   default:
165     llvm_unreachable("Unknown target flag on GV operand");
166   case X86II::MO_NO_FLAG:    // No flag.
167     break;
168   case X86II::MO_DARWIN_NONLAZY:
169   case X86II::MO_DLLIMPORT:
170   case X86II::MO_COFFSTUB:
171     // These affect the name of the symbol, not any suffix.
172     break;
173   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
174     O << " + [.-";
175     MF->getPICBaseSymbol()->print(O, MAI);
176     O << ']';
177     break;
178   case X86II::MO_PIC_BASE_OFFSET:
179   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
180     O << '-';
181     MF->getPICBaseSymbol()->print(O, MAI);
182     break;
183   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
184   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
185   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
186   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
187   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
188   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
189   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
190   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
191   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
192   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  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 
PrintOperand(const MachineInstr * MI,unsigned OpNo,raw_ostream & O)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.
PrintModifiedOperand(const MachineInstr * MI,unsigned OpNo,raw_ostream & O,const char * Modifier)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.
PrintPCRelImm(const MachineInstr * MI,unsigned OpNo,raw_ostream & O)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 
PrintLeaMemReference(const MachineInstr * MI,unsigned OpNo,raw_ostream & O,const char * Modifier)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 
PrintMemReference(const MachineInstr * MI,unsigned OpNo,raw_ostream & O,const char * Modifier)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 
PrintIntelMemReference(const MachineInstr * MI,unsigned OpNo,raw_ostream & O,const char * Modifier)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 this has a segment register, print it.
366   if (SegReg.getReg()) {
367     PrintOperand(MI, OpNo + X86::AddrSegmentReg, O);
368     O << ':';
369   }
370 
371   O << '[';
372 
373   bool NeedPlus = false;
374   if (HasBaseReg) {
375     PrintOperand(MI, OpNo + X86::AddrBaseReg, O);
376     NeedPlus = true;
377   }
378 
379   if (IndexReg.getReg()) {
380     if (NeedPlus) O << " + ";
381     if (ScaleVal != 1)
382       O << ScaleVal << '*';
383     PrintOperand(MI, OpNo + X86::AddrIndexReg, O);
384     NeedPlus = true;
385   }
386 
387   if (!DispSpec.isImm()) {
388     if (NeedPlus) O << " + ";
389     PrintOperand(MI, OpNo + X86::AddrDisp, O);
390   } else {
391     int64_t DispVal = DispSpec.getImm();
392     if (DispVal || (!IndexReg.getReg() && !HasBaseReg)) {
393       if (NeedPlus) {
394         if (DispVal > 0)
395           O << " + ";
396         else {
397           O << " - ";
398           DispVal = -DispVal;
399         }
400       }
401       O << DispVal;
402     }
403   }
404   O << ']';
405 }
406 
printAsmMRegister(const X86AsmPrinter & P,const MachineOperand & MO,char Mode,raw_ostream & O)407 static bool printAsmMRegister(const X86AsmPrinter &P, const MachineOperand &MO,
408                               char Mode, raw_ostream &O) {
409   Register Reg = MO.getReg();
410   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
411 
412   if (!X86::GR8RegClass.contains(Reg) &&
413       !X86::GR16RegClass.contains(Reg) &&
414       !X86::GR32RegClass.contains(Reg) &&
415       !X86::GR64RegClass.contains(Reg))
416     return true;
417 
418   switch (Mode) {
419   default: return true;  // Unknown mode.
420   case 'b': // Print QImode register
421     Reg = getX86SubSuperRegister(Reg, 8);
422     break;
423   case 'h': // Print QImode high register
424     Reg = getX86SubSuperRegister(Reg, 8, true);
425     break;
426   case 'w': // Print HImode register
427     Reg = getX86SubSuperRegister(Reg, 16);
428     break;
429   case 'k': // Print SImode register
430     Reg = getX86SubSuperRegister(Reg, 32);
431     break;
432   case 'V':
433     EmitPercent = false;
434     LLVM_FALLTHROUGH;
435   case 'q':
436     // Print 64-bit register names if 64-bit integer registers are available.
437     // Otherwise, print 32-bit register names.
438     Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
439     break;
440   }
441 
442   if (EmitPercent)
443     O << '%';
444 
445   O << X86ATTInstPrinter::getRegisterName(Reg);
446   return false;
447 }
448 
printAsmVRegister(const MachineOperand & MO,char Mode,raw_ostream & O)449 static bool printAsmVRegister(const MachineOperand &MO, char Mode,
450                               raw_ostream &O) {
451   Register Reg = MO.getReg();
452   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
453 
454   unsigned Index;
455   if (X86::VR128XRegClass.contains(Reg))
456     Index = Reg - X86::XMM0;
457   else if (X86::VR256XRegClass.contains(Reg))
458     Index = Reg - X86::YMM0;
459   else if (X86::VR512RegClass.contains(Reg))
460     Index = Reg - X86::ZMM0;
461   else
462     return true;
463 
464   switch (Mode) {
465   default: // Unknown mode.
466     return true;
467   case 'x': // Print V4SFmode register
468     Reg = X86::XMM0 + Index;
469     break;
470   case 't': // Print V8SFmode register
471     Reg = X86::YMM0 + Index;
472     break;
473   case 'g': // Print V16SFmode register
474     Reg = X86::ZMM0 + Index;
475     break;
476   }
477 
478   if (EmitPercent)
479     O << '%';
480 
481   O << X86ATTInstPrinter::getRegisterName(Reg);
482   return false;
483 }
484 
485 /// PrintAsmOperand - Print out an operand for an inline asm expression.
486 ///
PrintAsmOperand(const MachineInstr * MI,unsigned OpNo,const char * ExtraCode,raw_ostream & O)487 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
488                                     const char *ExtraCode, raw_ostream &O) {
489   // Does this asm operand have a single letter operand modifier?
490   if (ExtraCode && ExtraCode[0]) {
491     if (ExtraCode[1] != 0) return true; // Unknown modifier.
492 
493     const MachineOperand &MO = MI->getOperand(OpNo);
494 
495     switch (ExtraCode[0]) {
496     default:
497       // See if this is a generic print operand
498       return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
499     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
500       switch (MO.getType()) {
501       default:
502         return true;
503       case MachineOperand::MO_Immediate:
504         O << MO.getImm();
505         return false;
506       case MachineOperand::MO_ConstantPoolIndex:
507       case MachineOperand::MO_JumpTableIndex:
508       case MachineOperand::MO_ExternalSymbol:
509         llvm_unreachable("unexpected operand type!");
510       case MachineOperand::MO_GlobalAddress:
511         PrintSymbolOperand(MO, O);
512         if (Subtarget->isPICStyleRIPRel())
513           O << "(%rip)";
514         return false;
515       case MachineOperand::MO_Register:
516         O << '(';
517         PrintOperand(MI, OpNo, O);
518         O << ')';
519         return false;
520       }
521 
522     case 'c': // Don't print "$" before a global var name or constant.
523       switch (MO.getType()) {
524       default:
525         PrintOperand(MI, OpNo, O);
526         break;
527       case MachineOperand::MO_Immediate:
528         O << MO.getImm();
529         break;
530       case MachineOperand::MO_ConstantPoolIndex:
531       case MachineOperand::MO_JumpTableIndex:
532       case MachineOperand::MO_ExternalSymbol:
533         llvm_unreachable("unexpected operand type!");
534       case MachineOperand::MO_GlobalAddress:
535         PrintSymbolOperand(MO, O);
536         break;
537       }
538       return false;
539 
540     case 'A': // Print '*' before a register (it must be a register)
541       if (MO.isReg()) {
542         O << '*';
543         PrintOperand(MI, OpNo, O);
544         return false;
545       }
546       return true;
547 
548     case 'b': // Print QImode register
549     case 'h': // Print QImode high register
550     case 'w': // Print HImode register
551     case 'k': // Print SImode register
552     case 'q': // Print DImode register
553     case 'V': // Print native register without '%'
554       if (MO.isReg())
555         return printAsmMRegister(*this, MO, ExtraCode[0], O);
556       PrintOperand(MI, OpNo, O);
557       return false;
558 
559     case 'x': // Print V4SFmode register
560     case 't': // Print V8SFmode register
561     case 'g': // Print V16SFmode register
562       if (MO.isReg())
563         return printAsmVRegister(MO, ExtraCode[0], O);
564       PrintOperand(MI, OpNo, O);
565       return false;
566 
567     case 'P': // This is the operand of a call, treat specially.
568       PrintPCRelImm(MI, OpNo, O);
569       return false;
570 
571     case 'n': // Negate the immediate or print a '-' before the operand.
572       // Note: this is a temporary solution. It should be handled target
573       // independently as part of the 'MC' work.
574       if (MO.isImm()) {
575         O << -MO.getImm();
576         return false;
577       }
578       O << '-';
579     }
580   }
581 
582   PrintOperand(MI, OpNo, O);
583   return false;
584 }
585 
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNo,const char * ExtraCode,raw_ostream & O)586 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
587                                           const char *ExtraCode,
588                                           raw_ostream &O) {
589   if (ExtraCode && ExtraCode[0]) {
590     if (ExtraCode[1] != 0) return true; // Unknown modifier.
591 
592     switch (ExtraCode[0]) {
593     default: return true;  // Unknown modifier.
594     case 'b': // Print QImode register
595     case 'h': // Print QImode high register
596     case 'w': // Print HImode register
597     case 'k': // Print SImode register
598     case 'q': // Print SImode register
599       // These only apply to registers, ignore on mem.
600       break;
601     case 'H':
602       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
603         return true;  // Unsupported modifier in Intel inline assembly.
604       } else {
605         PrintMemReference(MI, OpNo, O, "H");
606       }
607       return false;
608     case 'P': // Don't print @PLT, but do print as memory.
609       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
610         PrintIntelMemReference(MI, OpNo, O, "no-rip");
611       } else {
612         PrintMemReference(MI, OpNo, O, "no-rip");
613       }
614       return false;
615     }
616   }
617   if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
618     PrintIntelMemReference(MI, OpNo, O, nullptr);
619   } else {
620     PrintMemReference(MI, OpNo, O, nullptr);
621   }
622   return false;
623 }
624 
emitStartOfAsmFile(Module & M)625 void X86AsmPrinter::emitStartOfAsmFile(Module &M) {
626   const Triple &TT = TM.getTargetTriple();
627 
628   if (TT.isOSBinFormatELF()) {
629     // Assemble feature flags that may require creation of a note section.
630     unsigned FeatureFlagsAnd = 0;
631     if (M.getModuleFlag("cf-protection-branch"))
632       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
633     if (M.getModuleFlag("cf-protection-return"))
634       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
635 
636     if (FeatureFlagsAnd) {
637       // Emit a .note.gnu.property section with the flags.
638       if (!TT.isArch32Bit() && !TT.isArch64Bit())
639         llvm_unreachable("CFProtection used on invalid architecture!");
640       MCSection *Cur = OutStreamer->getCurrentSectionOnly();
641       MCSection *Nt = MMI->getContext().getELFSection(
642           ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
643       OutStreamer->SwitchSection(Nt);
644 
645       // Emitting note header.
646       int WordSize = TT.isArch64Bit() ? 8 : 4;
647       emitAlignment(WordSize == 4 ? Align(4) : Align(8));
648       OutStreamer->emitIntValue(4, 4 /*size*/); // data size for "GNU\0"
649       OutStreamer->emitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
650       OutStreamer->emitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
651       OutStreamer->emitBytes(StringRef("GNU", 4)); // note name
652 
653       // Emitting an Elf_Prop for the CET properties.
654       OutStreamer->emitInt32(ELF::GNU_PROPERTY_X86_FEATURE_1_AND);
655       OutStreamer->emitInt32(4);                          // data size
656       OutStreamer->emitInt32(FeatureFlagsAnd);            // data
657       emitAlignment(WordSize == 4 ? Align(4) : Align(8)); // padding
658 
659       OutStreamer->endSection(Nt);
660       OutStreamer->SwitchSection(Cur);
661     }
662   }
663 
664   if (TT.isOSBinFormatMachO())
665     OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
666 
667   if (TT.isOSBinFormatCOFF()) {
668     // Emit an absolute @feat.00 symbol.  This appears to be some kind of
669     // compiler features bitfield read by link.exe.
670     MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
671     OutStreamer->BeginCOFFSymbolDef(S);
672     OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
673     OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
674     OutStreamer->EndCOFFSymbolDef();
675     int64_t Feat00Flags = 0;
676 
677     if (TT.getArch() == Triple::x86) {
678       // According to the PE-COFF spec, the LSB of this value marks the object
679       // for "registered SEH".  This means that all SEH handler entry points
680       // must be registered in .sxdata.  Use of any unregistered handlers will
681       // cause the process to terminate immediately.  LLVM does not know how to
682       // register any SEH handlers, so its object files should be safe.
683       Feat00Flags |= 1;
684     }
685 
686     if (M.getModuleFlag("cfguard"))
687       Feat00Flags |= 0x800; // Object is CFG-aware.
688 
689     OutStreamer->emitSymbolAttribute(S, MCSA_Global);
690     OutStreamer->emitAssignment(
691         S, MCConstantExpr::create(Feat00Flags, MMI->getContext()));
692   }
693   OutStreamer->emitSyntaxDirective();
694 
695   // If this is not inline asm and we're in 16-bit
696   // mode prefix assembly with .code16.
697   bool is16 = TT.getEnvironment() == Triple::CODE16;
698   if (M.getModuleInlineAsm().empty() && is16)
699     OutStreamer->emitAssemblerFlag(MCAF_Code16);
700 }
701 
702 static void
emitNonLazySymbolPointer(MCStreamer & OutStreamer,MCSymbol * StubLabel,MachineModuleInfoImpl::StubValueTy & MCSym)703 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
704                          MachineModuleInfoImpl::StubValueTy &MCSym) {
705   // L_foo$stub:
706   OutStreamer.emitLabel(StubLabel);
707   //   .indirect_symbol _foo
708   OutStreamer.emitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
709 
710   if (MCSym.getInt())
711     // External to current translation unit.
712     OutStreamer.emitIntValue(0, 4/*size*/);
713   else
714     // Internal to current translation unit.
715     //
716     // When we place the LSDA into the TEXT section, the type info
717     // pointers need to be indirect and pc-rel. We accomplish this by
718     // using NLPs; however, sometimes the types are local to the file.
719     // We need to fill in the value for the NLP in those cases.
720     OutStreamer.emitValue(
721         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
722         4 /*size*/);
723 }
724 
emitNonLazyStubs(MachineModuleInfo * MMI,MCStreamer & OutStreamer)725 static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
726 
727   MachineModuleInfoMachO &MMIMacho =
728       MMI->getObjFileInfo<MachineModuleInfoMachO>();
729 
730   // Output stubs for dynamically-linked functions.
731   MachineModuleInfoMachO::SymbolListTy Stubs;
732 
733   // Output stubs for external and common global variables.
734   Stubs = MMIMacho.GetGVStubList();
735   if (!Stubs.empty()) {
736     OutStreamer.SwitchSection(MMI->getContext().getMachOSection(
737         "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
738         SectionKind::getMetadata()));
739 
740     for (auto &Stub : Stubs)
741       emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
742 
743     Stubs.clear();
744     OutStreamer.AddBlankLine();
745   }
746 }
747 
emitEndOfAsmFile(Module & M)748 void X86AsmPrinter::emitEndOfAsmFile(Module &M) {
749   const Triple &TT = TM.getTargetTriple();
750 
751   if (TT.isOSBinFormatMachO()) {
752     // Mach-O uses non-lazy symbol stubs to encode per-TU information into
753     // global table for symbol lookup.
754     emitNonLazyStubs(MMI, *OutStreamer);
755 
756     // Emit stack and fault map information.
757     emitStackMaps(SM);
758     FM.serializeToFaultMapSection();
759 
760     // This flag tells the linker that no global symbols contain code that fall
761     // through to other global symbols (e.g. an implementation of multiple entry
762     // points). If this doesn't occur, the linker can safely perform dead code
763     // stripping. Since LLVM never generates code that does this, it is always
764     // safe to set.
765     OutStreamer->emitAssemblerFlag(MCAF_SubsectionsViaSymbols);
766   } else if (TT.isOSBinFormatCOFF()) {
767     if (MMI->usesMSVCFloatingPoint()) {
768       // In Windows' libcmt.lib, there is a file which is linked in only if the
769       // symbol _fltused is referenced. Linking this in causes some
770       // side-effects:
771       //
772       // 1. For x86-32, it will set the x87 rounding mode to 53-bit instead of
773       // 64-bit mantissas at program start.
774       //
775       // 2. It links in support routines for floating-point in scanf and printf.
776       //
777       // MSVC emits an undefined reference to _fltused when there are any
778       // floating point operations in the program (including calls). A program
779       // that only has: `scanf("%f", &global_float);` may fail to trigger this,
780       // but oh well...that's a documented issue.
781       StringRef SymbolName =
782           (TT.getArch() == Triple::x86) ? "__fltused" : "_fltused";
783       MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
784       OutStreamer->emitSymbolAttribute(S, MCSA_Global);
785       return;
786     }
787     emitStackMaps(SM);
788   } else if (TT.isOSBinFormatELF()) {
789     emitStackMaps(SM);
790     FM.serializeToFaultMapSection();
791   }
792 }
793 
794 //===----------------------------------------------------------------------===//
795 // Target Registry Stuff
796 //===----------------------------------------------------------------------===//
797 
798 // Force static initialization.
LLVMInitializeX86AsmPrinter()799 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86AsmPrinter() {
800   RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
801   RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
802 }
803