llvm/lib/Target/X86/X86AsmPrinter.cpp

   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/MachineValueType.h"
  27 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
  28 #include "llvm/IR/DerivedTypes.h"
  29 #include "llvm/IR/InlineAsm.h"
  30 #include "llvm/IR/Mangler.h"
  31 #include "llvm/IR/Module.h"
  32 #include "llvm/IR/Type.h"
  33 #include "llvm/MC/MCAsmInfo.h"
  34 #include "llvm/MC/MCCodeEmitter.h"
  35 #include "llvm/MC/MCContext.h"
  36 #include "llvm/MC/MCExpr.h"
  37 #include "llvm/MC/MCInstBuilder.h"
  38 #include "llvm/MC/MCSectionCOFF.h"
  39 #include "llvm/MC/MCSectionELF.h"
  40 #include "llvm/MC/MCSectionMachO.h"
  41 #include "llvm/MC/MCStreamer.h"
  42 #include "llvm/MC/MCSymbol.h"
  43 #include "llvm/MC/TargetRegistry.h"
  44 #include "llvm/Support/Debug.h"
  45 #include "llvm/Support/ErrorHandling.h"
  46 #include "llvm/Target/TargetMachine.h"
  47
  48 using namespace llvm;
  49
  50 X86AsmPrinter::X86AsmPrinter(TargetMachine &TM,
  51                              std::unique_ptr<MCStreamer> Streamer)
  52     : AsmPrinter(TM, std::move(Streamer)), FM(*this) {}
  53
  54 //===----------------------------------------------------------------------===//
  55 // Primitive Helper Functions.
  56 //===----------------------------------------------------------------------===//
  57
  58 /// runOnMachineFunction - Emit the function body.
  59 ///
  60 bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
  61   Subtarget = &MF.getSubtarget<X86Subtarget>();
  62
  63   SMShadowTracker.startFunction(MF);
  64   CodeEmitter.reset(TM.getTarget().createMCCodeEmitter(
  65       *Subtarget->getInstrInfo(), MF.getContext()));
  66
  67   EmitFPOData =
  68       Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag();
  69
  70   IndCSPrefix =
  71       MF.getMMI().getModule()->getModuleFlag("indirect_branch_cs_prefix");
  72
  73   SetupMachineFunction(MF);
  74
  75   if (Subtarget->isTargetCOFF()) {
  76     bool Local = MF.getFunction().hasLocalLinkage();
  77     OutStreamer->beginCOFFSymbolDef(CurrentFnSym);
  78     OutStreamer->emitCOFFSymbolStorageClass(
  79         Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL);
  80     OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
  81                                     << COFF::SCT_COMPLEX_TYPE_SHIFT);
  82     OutStreamer->endCOFFSymbolDef();
  83   }
  84
  85   // Emit the rest of the function body.
  86   emitFunctionBody();
  87
  88   // Emit the XRay table for this function.
  89   emitXRayTable();
  90
  91   EmitFPOData = false;
  92
  93   IndCSPrefix = false;
  94
  95   // We didn't modify anything.
  96   return false;
  97 }
  98
  99 void X86AsmPrinter::emitFunctionBodyStart() {
 100   if (EmitFPOData) {
 101     auto *XTS =
 102         static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer());
 103     XTS->emitFPOProc(
 104         CurrentFnSym,
 105         MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize());
 106   }
 107 }
 108
 109 void X86AsmPrinter::emitFunctionBodyEnd() {
 110   if (EmitFPOData) {
 111     auto *XTS =
 112         static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer());
 113     XTS->emitFPOEndProc();
 114   }
 115 }
 116
 117 uint32_t X86AsmPrinter::MaskKCFIType(uint32_t Value) {
 118   // If the type hash matches an invalid pattern, mask the value.
 119   const uint32_t InvalidValues[] = {
 120       0xFA1E0FF3, /* ENDBR64 */
 121       0xFB1E0FF3, /* ENDBR32 */
 122   };
 123   for (uint32_t N : InvalidValues) {
 124     // LowerKCFI_CHECK emits -Value for indirect call checks, so we must also
 125     // mask that. Note that -(Value + 1) == ~Value.
 126     if (N == Value || -N == Value)
 127       return Value + 1;
 128   }
 129   return Value;
 130 }
 131
 132 void X86AsmPrinter::EmitKCFITypePadding(const MachineFunction &MF,
 133                                         bool HasType) {
 134   // Keep the function entry aligned, taking patchable-function-prefix into
 135   // account if set.
 136   int64_t PrefixBytes = 0;
 137   (void)MF.getFunction()
 138       .getFnAttribute("patchable-function-prefix")
 139       .getValueAsString()
 140       .getAsInteger(10, PrefixBytes);
 141
 142   // Also take the type identifier into account if we're emitting
 143   // one. Otherwise, just pad with nops. The X86::MOV32ri instruction emitted
 144   // in X86AsmPrinter::emitKCFITypeId is 5 bytes long.
 145   if (HasType)
 146     PrefixBytes += 5;
 147
 148   emitNops(offsetToAlignment(PrefixBytes, MF.getAlignment()));
 149 }
 150
 151 /// emitKCFITypeId - Emit the KCFI type information in architecture specific
 152 /// format.
 153 void X86AsmPrinter::emitKCFITypeId(const MachineFunction &MF) {
 154   const Function &F = MF.getFunction();
 155   if (!F.getParent()->getModuleFlag("kcfi"))
 156     return;
 157
 158   ConstantInt *Type = nullptr;
 159   if (const MDNode *MD = F.getMetadata(LLVMContext::MD_kcfi_type))
 160     Type = mdconst::extract<ConstantInt>(MD->getOperand(0));
 161
 162   // If we don't have a type to emit, just emit padding if needed to maintain
 163   // the same alignment for all functions.
 164   if (!Type) {
 165     EmitKCFITypePadding(MF, /*HasType=*/false);
 166     return;
 167   }
 168
 169   // Emit a function symbol for the type data to avoid unreachable instruction
 170   // warnings from binary validation tools, and use the same linkage as the
 171   // parent function. Note that using local linkage would result in duplicate
 172   // symbols for weak parent functions.
 173   MCSymbol *FnSym = OutContext.getOrCreateSymbol("__cfi_" + MF.getName());
 174   emitLinkage(&MF.getFunction(), FnSym);
 175   if (MAI->hasDotTypeDotSizeDirective())
 176     OutStreamer->emitSymbolAttribute(FnSym, MCSA_ELF_TypeFunction);
 177   OutStreamer->emitLabel(FnSym);
 178
 179   // Embed the type hash in the X86::MOV32ri instruction to avoid special
 180   // casing object file parsers.
 181   EmitKCFITypePadding(MF);
 182   EmitAndCountInstruction(MCInstBuilder(X86::MOV32ri)
 183                               .addReg(X86::EAX)
 184                               .addImm(MaskKCFIType(Type->getZExtValue())));
 185
 186   if (MAI->hasDotTypeDotSizeDirective()) {
 187     MCSymbol *EndSym = OutContext.createTempSymbol("cfi_func_end");
 188     OutStreamer->emitLabel(EndSym);
 189
 190     const MCExpr *SizeExp = MCBinaryExpr::createSub(
 191         MCSymbolRefExpr::create(EndSym, OutContext),
 192         MCSymbolRefExpr::create(FnSym, OutContext), OutContext);
 193     OutStreamer->emitELFSize(FnSym, SizeExp);
 194   }
 195 }
 196
 197 /// PrintSymbolOperand - Print a raw symbol reference operand.  This handles
 198 /// jump tables, constant pools, global address and external symbols, all of
 199 /// which print to a label with various suffixes for relocation types etc.
 200 void X86AsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
 201                                        raw_ostream &O) {
 202   switch (MO.getType()) {
 203   default: llvm_unreachable("unknown symbol type!");
 204   case MachineOperand::MO_ConstantPoolIndex:
 205     GetCPISymbol(MO.getIndex())->print(O, MAI);
 206     printOffset(MO.getOffset(), O);
 207     break;
 208   case MachineOperand::MO_GlobalAddress: {
 209     const GlobalValue *GV = MO.getGlobal();
 210
 211     MCSymbol *GVSym;
 212     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
 213         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE)
 214       GVSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
 215     else
 216       GVSym = getSymbolPreferLocal(*GV);
 217
 218     // Handle dllimport linkage.
 219     if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
 220       GVSym = OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
 221     else if (MO.getTargetFlags() == X86II::MO_COFFSTUB)
 222       GVSym =
 223           OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName());
 224
 225     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
 226         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
 227       MCSymbol *Sym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
 228       MachineModuleInfoImpl::StubValueTy &StubSym =
 229           MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
 230       if (!StubSym.getPointer())
 231         StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV),
 232                                                      !GV->hasInternalLinkage());
 233     }
 234
 235     // If the name begins with a dollar-sign, enclose it in parens.  We do this
 236     // to avoid having it look like an integer immediate to the assembler.
 237     if (GVSym->getName()[0] != '$')
 238       GVSym->print(O, MAI);
 239     else {
 240       O << '(';
 241       GVSym->print(O, MAI);
 242       O << ')';
 243     }
 244     printOffset(MO.getOffset(), O);
 245     break;
 246   }
 247   }
 248
 249   switch (MO.getTargetFlags()) {
 250   default:
 251     llvm_unreachable("Unknown target flag on GV operand");
 252   case X86II::MO_NO_FLAG:    // No flag.
 253     break;
 254   case X86II::MO_DARWIN_NONLAZY:
 255   case X86II::MO_DLLIMPORT:
 256   case X86II::MO_COFFSTUB:
 257     // These affect the name of the symbol, not any suffix.
 258     break;
 259   case X86II::MO_GOT_ABSOLUTE_ADDRESS:
 260     O << " + [.-";
 261     MF->getPICBaseSymbol()->print(O, MAI);
 262     O << ']';
 263     break;
 264   case X86II::MO_PIC_BASE_OFFSET:
 265   case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
 266     O << '-';
 267     MF->getPICBaseSymbol()->print(O, MAI);
 268     break;
 269   case X86II::MO_TLSGD:     O << "@TLSGD";     break;
 270   case X86II::MO_TLSLD:     O << "@TLSLD";     break;
 271   case X86II::MO_TLSLDM:    O << "@TLSLDM";    break;
 272   case X86II::MO_GOTTPOFF:  O << "@GOTTPOFF";  break;
 273   case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
 274   case X86II::MO_TPOFF:     O << "@TPOFF";     break;
 275   case X86II::MO_DTPOFF:    O << "@DTPOFF";    break;
 276   case X86II::MO_NTPOFF:    O << "@NTPOFF";    break;
 277   case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
 278   case X86II::MO_GOTPCREL:  O << "@GOTPCREL";  break;
 279   case X86II::MO_GOTPCREL_NORELAX: O << "@GOTPCREL_NORELAX"; break;
 280   case X86II::MO_GOT:       O << "@GOT";       break;
 281   case X86II::MO_GOTOFF:    O << "@GOTOFF";    break;
 282   case X86II::MO_PLT:       O << "@PLT";       break;
 283   case X86II::MO_TLVP:      O << "@TLVP";      break;
 284   case X86II::MO_TLVP_PIC_BASE:
 285     O << "@TLVP" << '-';
 286     MF->getPICBaseSymbol()->print(O, MAI);
 287     break;
 288   case X86II::MO_SECREL:    O << "@SECREL32";  break;
 289   }
 290 }
 291
 292 void X86AsmPrinter::PrintOperand(const MachineInstr *MI, unsigned OpNo,
 293                                  raw_ostream &O) {
 294   const MachineOperand &MO = MI->getOperand(OpNo);
 295   const bool IsATT = MI->getInlineAsmDialect() == InlineAsm::AD_ATT;
 296   switch (MO.getType()) {
 297   default: llvm_unreachable("unknown operand type!");
 298   case MachineOperand::MO_Register: {
 299     if (IsATT)
 300       O << '%';
 301     O << X86ATTInstPrinter::getRegisterName(MO.getReg());
 302     return;
 303   }
 304
 305   case MachineOperand::MO_Immediate:
 306     if (IsATT)
 307       O << '$';
 308     O << MO.getImm();
 309     return;
 310
 311   case MachineOperand::MO_ConstantPoolIndex:
 312   case MachineOperand::MO_GlobalAddress: {
 313     switch (MI->getInlineAsmDialect()) {
 314     case InlineAsm::AD_ATT:
 315       O << '$';
 316       break;
 317     case InlineAsm::AD_Intel:
 318       O << "offset ";
 319       break;
 320     }
 321     PrintSymbolOperand(MO, O);
 322     break;
 323   }
 324   case MachineOperand::MO_BlockAddress: {
 325     MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress());
 326     Sym->print(O, MAI);
 327     break;
 328   }
 329   }
 330 }
 331
 332 /// PrintModifiedOperand - Print subregisters based on supplied modifier,
 333 /// deferring to PrintOperand() if no modifier was supplied or if operand is not
 334 /// a register.
 335 void X86AsmPrinter::PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo,
 336                                          raw_ostream &O, const char *Modifier) {
 337   const MachineOperand &MO = MI->getOperand(OpNo);
 338   if (!Modifier || !MO.isReg())
 339     return PrintOperand(MI, OpNo, O);
 340   if (MI->getInlineAsmDialect() == InlineAsm::AD_ATT)
 341     O << '%';
 342   Register Reg = MO.getReg();
 343   if (strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
 344     unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
 345         (strcmp(Modifier+6,"32") == 0) ? 32 :
 346         (strcmp(Modifier+6,"16") == 0) ? 16 : 8;
 347     Reg = getX86SubSuperRegister(Reg, Size);
 348   }
 349   O << X86ATTInstPrinter::getRegisterName(Reg);
 350 }
 351
 352 /// PrintPCRelImm - This is used to print an immediate value that ends up
 353 /// being encoded as a pc-relative value.  These print slightly differently, for
 354 /// example, a $ is not emitted.
 355 void X86AsmPrinter::PrintPCRelImm(const MachineInstr *MI, unsigned OpNo,
 356                                   raw_ostream &O) {
 357   const MachineOperand &MO = MI->getOperand(OpNo);
 358   switch (MO.getType()) {
 359   default: llvm_unreachable("Unknown pcrel immediate operand");
 360   case MachineOperand::MO_Register:
 361     // pc-relativeness was handled when computing the value in the reg.
 362     PrintOperand(MI, OpNo, O);
 363     return;
 364   case MachineOperand::MO_Immediate:
 365     O << MO.getImm();
 366     return;
 367   case MachineOperand::MO_GlobalAddress:
 368     PrintSymbolOperand(MO, O);
 369     return;
 370   }
 371 }
 372
 373 void X86AsmPrinter::PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo,
 374                                          raw_ostream &O, const char *Modifier) {
 375   const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
 376   const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
 377   const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
 378
 379   // If we really don't want to print out (rip), don't.
 380   bool HasBaseReg = BaseReg.getReg() != 0;
 381   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
 382       BaseReg.getReg() == X86::RIP)
 383     HasBaseReg = false;
 384
 385   // HasParenPart - True if we will print out the () part of the mem ref.
 386   bool HasParenPart = IndexReg.getReg() || HasBaseReg;
 387
 388   switch (DispSpec.getType()) {
 389   default:
 390     llvm_unreachable("unknown operand type!");
 391   case MachineOperand::MO_Immediate: {
 392     int DispVal = DispSpec.getImm();
 393     if (DispVal || !HasParenPart)
 394       O << DispVal;
 395     break;
 396   }
 397   case MachineOperand::MO_GlobalAddress:
 398   case MachineOperand::MO_ConstantPoolIndex:
 399     PrintSymbolOperand(DispSpec, O);
 400     break;
 401   }
 402
 403   if (Modifier && strcmp(Modifier, "H") == 0)
 404     O << "+8";
 405
 406   if (HasParenPart) {
 407     assert(IndexReg.getReg() != X86::ESP &&
 408            "X86 doesn't allow scaling by ESP");
 409
 410     O << '(';
 411     if (HasBaseReg)
 412       PrintModifiedOperand(MI, OpNo + X86::AddrBaseReg, O, Modifier);
 413
 414     if (IndexReg.getReg()) {
 415       O << ',';
 416       PrintModifiedOperand(MI, OpNo + X86::AddrIndexReg, O, Modifier);
 417       unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
 418       if (ScaleVal != 1)
 419         O << ',' << ScaleVal;
 420     }
 421     O << ')';
 422   }
 423 }
 424
 425 static bool isSimpleReturn(const MachineInstr &MI) {
 426   // We exclude all tail calls here which set both isReturn and isCall.
 427   return MI.getDesc().isReturn() && !MI.getDesc().isCall();
 428 }
 429
 430 static bool isIndirectBranchOrTailCall(const MachineInstr &MI) {
 431   unsigned Opc = MI.getOpcode();
 432   return MI.getDesc().isIndirectBranch() /*Make below code in a good shape*/ ||
 433          Opc == X86::TAILJMPr || Opc == X86::TAILJMPm ||
 434          Opc == X86::TAILJMPr64 || Opc == X86::TAILJMPm64 ||
 435          Opc == X86::TCRETURNri || Opc == X86::TCRETURNmi ||
 436          Opc == X86::TCRETURNri64 || Opc == X86::TCRETURNmi64 ||
 437          Opc == X86::TAILJMPr64_REX || Opc == X86::TAILJMPm64_REX;
 438 }
 439
 440 void X86AsmPrinter::emitBasicBlockEnd(const MachineBasicBlock &MBB) {
 441   if (Subtarget->hardenSlsRet() || Subtarget->hardenSlsIJmp()) {
 442     auto I = MBB.getLastNonDebugInstr();
 443     if (I != MBB.end()) {
 444       if ((Subtarget->hardenSlsRet() && isSimpleReturn(*I)) ||
 445           (Subtarget->hardenSlsIJmp() && isIndirectBranchOrTailCall(*I))) {
 446         MCInst TmpInst;
 447         TmpInst.setOpcode(X86::INT3);
 448         EmitToStreamer(*OutStreamer, TmpInst);
 449       }
 450     }
 451   }
 452   AsmPrinter::emitBasicBlockEnd(MBB);
 453   SMShadowTracker.emitShadowPadding(*OutStreamer, getSubtargetInfo());
 454 }
 455
 456 void X86AsmPrinter::PrintMemReference(const MachineInstr *MI, unsigned OpNo,
 457                                       raw_ostream &O, const char *Modifier) {
 458   assert(isMem(*MI, OpNo) && "Invalid memory reference!");
 459   const MachineOperand &Segment = MI->getOperand(OpNo + X86::AddrSegmentReg);
 460   if (Segment.getReg()) {
 461     PrintModifiedOperand(MI, OpNo + X86::AddrSegmentReg, O, Modifier);
 462     O << ':';
 463   }
 464   PrintLeaMemReference(MI, OpNo, O, Modifier);
 465 }
 466
 467
 468 void X86AsmPrinter::PrintIntelMemReference(const MachineInstr *MI,
 469                                            unsigned OpNo, raw_ostream &O,
 470                                            const char *Modifier) {
 471   const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
 472   unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
 473   const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
 474   const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
 475   const MachineOperand &SegReg = MI->getOperand(OpNo + X86::AddrSegmentReg);
 476
 477   // If we really don't want to print out (rip), don't.
 478   bool HasBaseReg = BaseReg.getReg() != 0;
 479   if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
 480       BaseReg.getReg() == X86::RIP)
 481     HasBaseReg = false;
 482
 483   // If we really just want to print out displacement.
 484   if (Modifier && (DispSpec.isGlobal() || DispSpec.isSymbol()) &&
 485       !strcmp(Modifier, "disp-only")) {
 486     HasBaseReg = false;
 487   }
 488
 489   // If this has a segment register, print it.
 490   if (SegReg.getReg()) {
 491     PrintOperand(MI, OpNo + X86::AddrSegmentReg, O);
 492     O << ':';
 493   }
 494
 495   O << '[';
 496
 497   bool NeedPlus = false;
 498   if (HasBaseReg) {
 499     PrintOperand(MI, OpNo + X86::AddrBaseReg, O);
 500     NeedPlus = true;
 501   }
 502
 503   if (IndexReg.getReg()) {
 504     if (NeedPlus) O << " + ";
 505     if (ScaleVal != 1)
 506       O << ScaleVal << '*';
 507     PrintOperand(MI, OpNo + X86::AddrIndexReg, O);
 508     NeedPlus = true;
 509   }
 510
 511   if (!DispSpec.isImm()) {
 512     if (NeedPlus) O << " + ";
 513     // Do not add `offset` operator. Matches the behaviour of
 514     // X86IntelInstPrinter::printMemReference.
 515     PrintSymbolOperand(DispSpec, O);
 516   } else {
 517     int64_t DispVal = DispSpec.getImm();
 518     if (DispVal || (!IndexReg.getReg() && !HasBaseReg)) {
 519       if (NeedPlus) {
 520         if (DispVal > 0)
 521           O << " + ";
 522         else {
 523           O << " - ";
 524           DispVal = -DispVal;
 525         }
 526       }
 527       O << DispVal;
 528     }
 529   }
 530   O << ']';
 531 }
 532
 533 static bool printAsmMRegister(const X86AsmPrinter &P, const MachineOperand &MO,
 534                               char Mode, raw_ostream &O) {
 535   Register Reg = MO.getReg();
 536   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
 537
 538   if (!X86::GR8RegClass.contains(Reg) &&
 539       !X86::GR16RegClass.contains(Reg) &&
 540       !X86::GR32RegClass.contains(Reg) &&
 541       !X86::GR64RegClass.contains(Reg))
 542     return true;
 543
 544   switch (Mode) {
 545   default: return true;  // Unknown mode.
 546   case 'b': // Print QImode register
 547     Reg = getX86SubSuperRegister(Reg, 8);
 548     break;
 549   case 'h': // Print QImode high register
 550     Reg = getX86SubSuperRegister(Reg, 8, true);
 551     if (!Reg.isValid())
 552       return true;
 553     break;
 554   case 'w': // Print HImode register
 555     Reg = getX86SubSuperRegister(Reg, 16);
 556     break;
 557   case 'k': // Print SImode register
 558     Reg = getX86SubSuperRegister(Reg, 32);
 559     break;
 560   case 'V':
 561     EmitPercent = false;
 562     [[fallthrough]];
 563   case 'q':
 564     // Print 64-bit register names if 64-bit integer registers are available.
 565     // Otherwise, print 32-bit register names.
 566     Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
 567     break;
 568   }
 569
 570   if (EmitPercent)
 571     O << '%';
 572
 573   O << X86ATTInstPrinter::getRegisterName(Reg);
 574   return false;
 575 }
 576
 577 static bool printAsmVRegister(const MachineOperand &MO, char Mode,
 578                               raw_ostream &O) {
 579   Register Reg = MO.getReg();
 580   bool EmitPercent = MO.getParent()->getInlineAsmDialect() == InlineAsm::AD_ATT;
 581
 582   unsigned Index;
 583   if (X86::VR128XRegClass.contains(Reg))
 584     Index = Reg - X86::XMM0;
 585   else if (X86::VR256XRegClass.contains(Reg))
 586     Index = Reg - X86::YMM0;
 587   else if (X86::VR512RegClass.contains(Reg))
 588     Index = Reg - X86::ZMM0;
 589   else
 590     return true;
 591
 592   switch (Mode) {
 593   default: // Unknown mode.
 594     return true;
 595   case 'x': // Print V4SFmode register
 596     Reg = X86::XMM0 + Index;
 597     break;
 598   case 't': // Print V8SFmode register
 599     Reg = X86::YMM0 + Index;
 600     break;
 601   case 'g': // Print V16SFmode register
 602     Reg = X86::ZMM0 + Index;
 603     break;
 604   }
 605
 606   if (EmitPercent)
 607     O << '%';
 608
 609   O << X86ATTInstPrinter::getRegisterName(Reg);
 610   return false;
 611 }
 612
 613 /// PrintAsmOperand - Print out an operand for an inline asm expression.
 614 ///
 615 bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 616                                     const char *ExtraCode, raw_ostream &O) {
 617   // Does this asm operand have a single letter operand modifier?
 618   if (ExtraCode && ExtraCode[0]) {
 619     if (ExtraCode[1] != 0) return true; // Unknown modifier.
 620
 621     const MachineOperand &MO = MI->getOperand(OpNo);
 622
 623     switch (ExtraCode[0]) {
 624     default:
 625       // See if this is a generic print operand
 626       return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
 627     case 'a': // This is an address.  Currently only 'i' and 'r' are expected.
 628       switch (MO.getType()) {
 629       default:
 630         return true;
 631       case MachineOperand::MO_Immediate:
 632         O << MO.getImm();
 633         return false;
 634       case MachineOperand::MO_ConstantPoolIndex:
 635       case MachineOperand::MO_JumpTableIndex:
 636       case MachineOperand::MO_ExternalSymbol:
 637         llvm_unreachable("unexpected operand type!");
 638       case MachineOperand::MO_GlobalAddress:
 639         PrintSymbolOperand(MO, O);
 640         if (Subtarget->isPICStyleRIPRel())
 641           O << "(%rip)";
 642         return false;
 643       case MachineOperand::MO_Register:
 644         O << '(';
 645         PrintOperand(MI, OpNo, O);
 646         O << ')';
 647         return false;
 648       }
 649
 650     case 'c': // Don't print "$" before a global var name or constant.
 651       switch (MO.getType()) {
 652       default:
 653         PrintOperand(MI, OpNo, O);
 654         break;
 655       case MachineOperand::MO_Immediate:
 656         O << MO.getImm();
 657         break;
 658       case MachineOperand::MO_ConstantPoolIndex:
 659       case MachineOperand::MO_JumpTableIndex:
 660       case MachineOperand::MO_ExternalSymbol:
 661         llvm_unreachable("unexpected operand type!");
 662       case MachineOperand::MO_GlobalAddress:
 663         PrintSymbolOperand(MO, O);
 664         break;
 665       }
 666       return false;
 667
 668     case 'A': // Print '*' before a register (it must be a register)
 669       if (MO.isReg()) {
 670         O << '*';
 671         PrintOperand(MI, OpNo, O);
 672         return false;
 673       }
 674       return true;
 675
 676     case 'b': // Print QImode register
 677     case 'h': // Print QImode high register
 678     case 'w': // Print HImode register
 679     case 'k': // Print SImode register
 680     case 'q': // Print DImode register
 681     case 'V': // Print native register without '%'
 682       if (MO.isReg())
 683         return printAsmMRegister(*this, MO, ExtraCode[0], O);
 684       PrintOperand(MI, OpNo, O);
 685       return false;
 686
 687     case 'x': // Print V4SFmode register
 688     case 't': // Print V8SFmode register
 689     case 'g': // Print V16SFmode register
 690       if (MO.isReg())
 691         return printAsmVRegister(MO, ExtraCode[0], O);
 692       PrintOperand(MI, OpNo, O);
 693       return false;
 694
 695     case 'P': // This is the operand of a call, treat specially.
 696       PrintPCRelImm(MI, OpNo, O);
 697       return false;
 698
 699     case 'n': // Negate the immediate or print a '-' before the operand.
 700       // Note: this is a temporary solution. It should be handled target
 701       // independently as part of the 'MC' work.
 702       if (MO.isImm()) {
 703         O << -MO.getImm();
 704         return false;
 705       }
 706       O << '-';
 707     }
 708   }
 709
 710   PrintOperand(MI, OpNo, O);
 711   return false;
 712 }
 713
 714 bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
 715                                           const char *ExtraCode,
 716                                           raw_ostream &O) {
 717   if (ExtraCode && ExtraCode[0]) {
 718     if (ExtraCode[1] != 0) return true; // Unknown modifier.
 719
 720     switch (ExtraCode[0]) {
 721     default: return true;  // Unknown modifier.
 722     case 'b': // Print QImode register
 723     case 'h': // Print QImode high register
 724     case 'w': // Print HImode register
 725     case 'k': // Print SImode register
 726     case 'q': // Print SImode register
 727       // These only apply to registers, ignore on mem.
 728       break;
 729     case 'H':
 730       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
 731         return true;  // Unsupported modifier in Intel inline assembly.
 732       } else {
 733         PrintMemReference(MI, OpNo, O, "H");
 734       }
 735       return false;
 736    // Print memory only with displacement. The Modifer 'P' is used in inline
 737    // asm to present a call symbol or a global symbol which can not use base
 738    // reg or index reg.
 739     case 'P':
 740       if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
 741         PrintIntelMemReference(MI, OpNo, O, "disp-only");
 742       } else {
 743         PrintMemReference(MI, OpNo, O, "disp-only");
 744       }
 745       return false;
 746     }
 747   }
 748   if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
 749     PrintIntelMemReference(MI, OpNo, O, nullptr);
 750   } else {
 751     PrintMemReference(MI, OpNo, O, nullptr);
 752   }
 753   return false;
 754 }
 755
 756 void X86AsmPrinter::emitStartOfAsmFile(Module &M) {
 757   const Triple &TT = TM.getTargetTriple();
 758
 759   if (TT.isOSBinFormatELF()) {
 760     // Assemble feature flags that may require creation of a note section.
 761     unsigned FeatureFlagsAnd = 0;
 762     if (M.getModuleFlag("cf-protection-branch"))
 763       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
 764     if (M.getModuleFlag("cf-protection-return"))
 765       FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
 766
 767     if (FeatureFlagsAnd) {
 768       // Emit a .note.gnu.property section with the flags.
 769       assert((TT.isArch32Bit() || TT.isArch64Bit()) &&
 770              "CFProtection used on invalid architecture!");
 771       MCSection *Cur = OutStreamer->getCurrentSectionOnly();
 772       MCSection *Nt = MMI->getContext().getELFSection(
 773           ".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
 774       OutStreamer->switchSection(Nt);
 775
 776       // Emitting note header.
 777       const int WordSize = TT.isArch64Bit() && !TT.isX32() ? 8 : 4;
 778       emitAlignment(WordSize == 4 ? Align(4) : Align(8));
 779       OutStreamer->emitIntValue(4, 4 /*size*/); // data size for "GNU\0"
 780       OutStreamer->emitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
 781       OutStreamer->emitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
 782       OutStreamer->emitBytes(StringRef("GNU", 4)); // note name
 783
 784       // Emitting an Elf_Prop for the CET properties.
 785       OutStreamer->emitInt32(ELF::GNU_PROPERTY_X86_FEATURE_1_AND);
 786       OutStreamer->emitInt32(4);                          // data size
 787       OutStreamer->emitInt32(FeatureFlagsAnd);            // data
 788       emitAlignment(WordSize == 4 ? Align(4) : Align(8)); // padding
 789
 790       OutStreamer->endSection(Nt);
 791       OutStreamer->switchSection(Cur);
 792     }
 793   }
 794
 795   if (TT.isOSBinFormatMachO())
 796     OutStreamer->switchSection(getObjFileLowering().getTextSection());
 797
 798   if (TT.isOSBinFormatCOFF()) {
 799     // Emit an absolute @feat.00 symbol.
 800     MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
 801     OutStreamer->beginCOFFSymbolDef(S);
 802     OutStreamer->emitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
 803     OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
 804     OutStreamer->endCOFFSymbolDef();
 805     int64_t Feat00Value = 0;
 806
 807     if (TT.getArch() == Triple::x86) {
 808       // According to the PE-COFF spec, the LSB of this value marks the object
 809       // for "registered SEH".  This means that all SEH handler entry points
 810       // must be registered in .sxdata.  Use of any unregistered handlers will
 811       // cause the process to terminate immediately.  LLVM does not know how to
 812       // register any SEH handlers, so its object files should be safe.
 813       Feat00Value |= COFF::Feat00Flags::SafeSEH;
 814     }
 815
 816     if (M.getModuleFlag("cfguard")) {
 817       // Object is CFG-aware.
 818       Feat00Value |= COFF::Feat00Flags::GuardCF;
 819     }
 820
 821     if (M.getModuleFlag("ehcontguard")) {
 822       // Object also has EHCont.
 823       Feat00Value |= COFF::Feat00Flags::GuardEHCont;
 824     }
 825
 826     if (M.getModuleFlag("ms-kernel")) {
 827       // Object is compiled with /kernel.
 828       Feat00Value |= COFF::Feat00Flags::Kernel;
 829     }
 830
 831     OutStreamer->emitSymbolAttribute(S, MCSA_Global);
 832     OutStreamer->emitAssignment(
 833         S, MCConstantExpr::create(Feat00Value, MMI->getContext()));
 834   }
 835   OutStreamer->emitSyntaxDirective();
 836
 837   // If this is not inline asm and we're in 16-bit
 838   // mode prefix assembly with .code16.
 839   bool is16 = TT.getEnvironment() == Triple::CODE16;
 840   if (M.getModuleInlineAsm().empty() && is16)
 841     OutStreamer->emitAssemblerFlag(MCAF_Code16);
 842 }
 843
 844 static void
 845 emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
 846                          MachineModuleInfoImpl::StubValueTy &MCSym) {
 847   // L_foo$stub:
 848   OutStreamer.emitLabel(StubLabel);
 849   //   .indirect_symbol _foo
 850   OutStreamer.emitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
 851
 852   if (MCSym.getInt())
 853     // External to current translation unit.
 854     OutStreamer.emitIntValue(0, 4/*size*/);
 855   else
 856     // Internal to current translation unit.
 857     //
 858     // When we place the LSDA into the TEXT section, the type info
 859     // pointers need to be indirect and pc-rel. We accomplish this by
 860     // using NLPs; however, sometimes the types are local to the file.
 861     // We need to fill in the value for the NLP in those cases.
 862     OutStreamer.emitValue(
 863         MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
 864         4 /*size*/);
 865 }
 866
 867 static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
 868
 869   MachineModuleInfoMachO &MMIMacho =
 870       MMI->getObjFileInfo<MachineModuleInfoMachO>();
 871
 872   // Output stubs for dynamically-linked functions.
 873   MachineModuleInfoMachO::SymbolListTy Stubs;
 874
 875   // Output stubs for external and common global variables.
 876   Stubs = MMIMacho.GetGVStubList();
 877   if (!Stubs.empty()) {
 878     OutStreamer.switchSection(MMI->getContext().getMachOSection(
 879         "__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
 880         SectionKind::getMetadata()));
 881
 882     for (auto &Stub : Stubs)
 883       emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
 884
 885     Stubs.clear();
 886     OutStreamer.addBlankLine();
 887   }
 888 }
 889
 890 void X86AsmPrinter::emitEndOfAsmFile(Module &M) {
 891   const Triple &TT = TM.getTargetTriple();
 892
 893   if (TT.isOSBinFormatMachO()) {
 894     // Mach-O uses non-lazy symbol stubs to encode per-TU information into
 895     // global table for symbol lookup.
 896     emitNonLazyStubs(MMI, *OutStreamer);
 897
 898     // Emit fault map information.
 899     FM.serializeToFaultMapSection();
 900
 901     // This flag tells the linker that no global symbols contain code that fall
 902     // through to other global symbols (e.g. an implementation of multiple entry
 903     // points). If this doesn't occur, the linker can safely perform dead code
 904     // stripping. Since LLVM never generates code that does this, it is always
 905     // safe to set.
 906     OutStreamer->emitAssemblerFlag(MCAF_SubsectionsViaSymbols);
 907   } else if (TT.isOSBinFormatCOFF()) {
 908     if (MMI->usesMSVCFloatingPoint()) {
 909       // In Windows' libcmt.lib, there is a file which is linked in only if the
 910       // symbol _fltused is referenced. Linking this in causes some
 911       // side-effects:
 912       //
 913       // 1. For x86-32, it will set the x87 rounding mode to 53-bit instead of
 914       // 64-bit mantissas at program start.
 915       //
 916       // 2. It links in support routines for floating-point in scanf and printf.
 917       //
 918       // MSVC emits an undefined reference to _fltused when there are any
 919       // floating point operations in the program (including calls). A program
 920       // that only has: `scanf("%f", &global_float);` may fail to trigger this,
 921       // but oh well...that's a documented issue.
 922       StringRef SymbolName =
 923           (TT.getArch() == Triple::x86) ? "__fltused" : "_fltused";
 924       MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
 925       OutStreamer->emitSymbolAttribute(S, MCSA_Global);
 926       return;
 927     }
 928   } else if (TT.isOSBinFormatELF()) {
 929     FM.serializeToFaultMapSection();
 930   }
 931
 932   // Emit __morestack address if needed for indirect calls.
 933   if (TT.getArch() == Triple::x86_64 && TM.getCodeModel() == CodeModel::Large) {
 934     if (MCSymbol *AddrSymbol = OutContext.lookupSymbol("__morestack_addr")) {
 935       Align Alignment(1);
 936       MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
 937           getDataLayout(), SectionKind::getReadOnly(),
 938           /*C=*/nullptr, Alignment);
 939       OutStreamer->switchSection(ReadOnlySection);
 940       OutStreamer->emitLabel(AddrSymbol);
 941
 942       unsigned PtrSize = MAI->getCodePointerSize();
 943       OutStreamer->emitSymbolValue(GetExternalSymbolSymbol("__morestack"),
 944                                    PtrSize);
 945     }
 946   }
 947 }
 948
 949 //===----------------------------------------------------------------------===//
 950 // Target Registry Stuff
 951 //===----------------------------------------------------------------------===//
 952
 953 // Force static initialization.
 954 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeX86AsmPrinter() {
 955   RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
 956   RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
 957 }