lib/MC/MCStreamer.cpp

   1 //===- lib/MC/MCStreamer.cpp - Streaming Machine Code Output --------------===//
   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 #include "llvm/MC/MCStreamer.h"
  10 #include "llvm/ADT/Optional.h"
  11 #include "llvm/ADT/SmallString.h"
  12 #include "llvm/ADT/StringRef.h"
  13 #include "llvm/ADT/Twine.h"
  14 #include "llvm/BinaryFormat/COFF.h"
  15 #include "llvm/MC/MCAsmBackend.h"
  16 #include "llvm/MC/MCAsmInfo.h"
  17 #include "llvm/MC/MCCodeView.h"
  18 #include "llvm/MC/MCContext.h"
  19 #include "llvm/MC/MCDwarf.h"
  20 #include "llvm/MC/MCExpr.h"
  21 #include "llvm/MC/MCInst.h"
  22 #include "llvm/MC/MCInstPrinter.h"
  23 #include "llvm/MC/MCObjectFileInfo.h"
  24 #include "llvm/MC/MCSection.h"
  25 #include "llvm/MC/MCSectionCOFF.h"
  26 #include "llvm/MC/MCSymbol.h"
  27 #include "llvm/MC/MCWin64EH.h"
  28 #include "llvm/MC/MCWinEH.h"
  29 #include "llvm/Support/Casting.h"
  30 #include "llvm/Support/ErrorHandling.h"
  31 #include "llvm/Support/LEB128.h"
  32 #include "llvm/Support/MathExtras.h"
  33 #include "llvm/Support/raw_ostream.h"
  34 #include <cassert>
  35 #include <cstdint>
  36 #include <cstdlib>
  37 #include <utility>
  38
  39 using namespace llvm;
  40
  41 MCTargetStreamer::MCTargetStreamer(MCStreamer &S) : Streamer(S) {
  42   S.setTargetStreamer(this);
  43 }
  44
  45 // Pin the vtables to this file.
  46 MCTargetStreamer::~MCTargetStreamer() = default;
  47
  48 void MCTargetStreamer::emitLabel(MCSymbol *Symbol) {}
  49
  50 void MCTargetStreamer::finish() {}
  51
  52 void MCTargetStreamer::changeSection(const MCSection *CurSection,
  53                                      MCSection *Section,
  54                                      const MCExpr *Subsection,
  55                                      raw_ostream &OS) {
  56   Section->PrintSwitchToSection(
  57       *Streamer.getContext().getAsmInfo(),
  58       Streamer.getContext().getObjectFileInfo()->getTargetTriple(), OS,
  59       Subsection);
  60 }
  61
  62 void MCTargetStreamer::emitDwarfFileDirective(StringRef Directive) {
  63   Streamer.EmitRawText(Directive);
  64 }
  65
  66 void MCTargetStreamer::emitValue(const MCExpr *Value) {
  67   SmallString<128> Str;
  68   raw_svector_ostream OS(Str);
  69
  70   Value->print(OS, Streamer.getContext().getAsmInfo());
  71   Streamer.EmitRawText(OS.str());
  72 }
  73
  74 void MCTargetStreamer::emitRawBytes(StringRef Data) {
  75   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
  76   const char *Directive = MAI->getData8bitsDirective();
  77   for (const unsigned char C : Data.bytes()) {
  78     SmallString<128> Str;
  79     raw_svector_ostream OS(Str);
  80
  81     OS << Directive << (unsigned)C;
  82     Streamer.EmitRawText(OS.str());
  83   }
  84 }
  85
  86 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
  87
  88 MCStreamer::MCStreamer(MCContext &Ctx)
  89     : Context(Ctx), CurrentWinFrameInfo(nullptr),
  90       UseAssemblerInfoForParsing(false) {
  91   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
  92 }
  93
  94 MCStreamer::~MCStreamer() {}
  95
  96 void MCStreamer::reset() {
  97   DwarfFrameInfos.clear();
  98   CurrentWinFrameInfo = nullptr;
  99   WinFrameInfos.clear();
 100   SymbolOrdering.clear();
 101   SectionStack.clear();
 102   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
 103 }
 104
 105 raw_ostream &MCStreamer::GetCommentOS() {
 106   // By default, discard comments.
 107   return nulls();
 108 }
 109
 110 void MCStreamer::emitRawComment(const Twine &T, bool TabPrefix) {}
 111
 112 void MCStreamer::addExplicitComment(const Twine &T) {}
 113 void MCStreamer::emitExplicitComments() {}
 114
 115 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
 116   for (auto &FI : DwarfFrameInfos)
 117     FI.CompactUnwindEncoding =
 118         (MAB ? MAB->generateCompactUnwindEncoding(FI.Instructions) : 0);
 119 }
 120
 121 /// EmitIntValue - Special case of EmitValue that avoids the client having to
 122 /// pass in a MCExpr for constant integers.
 123 void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size) {
 124   assert(1 <= Size && Size <= 8 && "Invalid size");
 125   assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
 126          "Invalid size");
 127   char buf[8];
 128   const bool isLittleEndian = Context.getAsmInfo()->isLittleEndian();
 129   for (unsigned i = 0; i != Size; ++i) {
 130     unsigned index = isLittleEndian ? i : (Size - i - 1);
 131     buf[i] = uint8_t(Value >> (index * 8));
 132   }
 133   EmitBytes(StringRef(buf, Size));
 134 }
 135
 136 /// EmitULEB128IntValue - Special case of EmitULEB128Value that avoids the
 137 /// client having to pass in a MCExpr for constant integers.
 138 void MCStreamer::EmitULEB128IntValue(uint64_t Value) {
 139   SmallString<128> Tmp;
 140   raw_svector_ostream OSE(Tmp);
 141   encodeULEB128(Value, OSE);
 142   EmitBytes(OSE.str());
 143 }
 144
 145 /// EmitSLEB128IntValue - Special case of EmitSLEB128Value that avoids the
 146 /// client having to pass in a MCExpr for constant integers.
 147 void MCStreamer::EmitSLEB128IntValue(int64_t Value) {
 148   SmallString<128> Tmp;
 149   raw_svector_ostream OSE(Tmp);
 150   encodeSLEB128(Value, OSE);
 151   EmitBytes(OSE.str());
 152 }
 153
 154 void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc) {
 155   EmitValueImpl(Value, Size, Loc);
 156 }
 157
 158 void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
 159                                  bool IsSectionRelative) {
 160   assert((!IsSectionRelative || Size == 4) &&
 161          "SectionRelative value requires 4-bytes");
 162
 163   if (!IsSectionRelative)
 164     EmitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
 165   else
 166     EmitCOFFSecRel32(Sym, /*Offset=*/0);
 167 }
 168
 169 void MCStreamer::EmitDTPRel64Value(const MCExpr *Value) {
 170   report_fatal_error("unsupported directive in streamer");
 171 }
 172
 173 void MCStreamer::EmitDTPRel32Value(const MCExpr *Value) {
 174   report_fatal_error("unsupported directive in streamer");
 175 }
 176
 177 void MCStreamer::EmitTPRel64Value(const MCExpr *Value) {
 178   report_fatal_error("unsupported directive in streamer");
 179 }
 180
 181 void MCStreamer::EmitTPRel32Value(const MCExpr *Value) {
 182   report_fatal_error("unsupported directive in streamer");
 183 }
 184
 185 void MCStreamer::EmitGPRel64Value(const MCExpr *Value) {
 186   report_fatal_error("unsupported directive in streamer");
 187 }
 188
 189 void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
 190   report_fatal_error("unsupported directive in streamer");
 191 }
 192
 193 /// Emit NumBytes bytes worth of the value specified by FillValue.
 194 /// This implements directives such as '.space'.
 195 void MCStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
 196   emitFill(*MCConstantExpr::create(NumBytes, getContext()), FillValue);
 197 }
 198
 199 /// The implementation in this class just redirects to emitFill.
 200 void MCStreamer::EmitZeros(uint64_t NumBytes) {
 201   emitFill(NumBytes, 0);
 202 }
 203
 204 Expected<unsigned>
 205 MCStreamer::tryEmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
 206                                       StringRef Filename,
 207                                       MD5::MD5Result *Checksum,
 208                                       Optional<StringRef> Source,
 209                                       unsigned CUID) {
 210   return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
 211                                    Source, CUID);
 212 }
 213
 214 void MCStreamer::emitDwarfFile0Directive(StringRef Directory,
 215                                          StringRef Filename,
 216                                          MD5::MD5Result *Checksum,
 217                                          Optional<StringRef> Source,
 218                                          unsigned CUID) {
 219   getContext().setMCLineTableRootFile(CUID, Directory, Filename, Checksum,
 220                                       Source);
 221 }
 222
 223 void MCStreamer::EmitCFIBKeyFrame() {
 224   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 225   if (!CurFrame)
 226     return;
 227   CurFrame->IsBKeyFrame = true;
 228 }
 229
 230 void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
 231                                        unsigned Column, unsigned Flags,
 232                                        unsigned Isa,
 233                                        unsigned Discriminator,
 234                                        StringRef FileName) {
 235   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
 236                                   Discriminator);
 237 }
 238
 239 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
 240   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
 241   if (!Table.getLabel()) {
 242     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
 243     Table.setLabel(
 244         Context.getOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
 245   }
 246   return Table.getLabel();
 247 }
 248
 249 bool MCStreamer::hasUnfinishedDwarfFrameInfo() {
 250   return !DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End;
 251 }
 252
 253 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
 254   if (!hasUnfinishedDwarfFrameInfo()) {
 255     getContext().reportError(SMLoc(), "this directive must appear between "
 256                                       ".cfi_startproc and .cfi_endproc "
 257                                       "directives");
 258     return nullptr;
 259   }
 260   return &DwarfFrameInfos.back();
 261 }
 262
 263 bool MCStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename,
 264                                      ArrayRef<uint8_t> Checksum,
 265                                      unsigned ChecksumKind) {
 266   return getContext().getCVContext().addFile(*this, FileNo, Filename, Checksum,
 267                                              ChecksumKind);
 268 }
 269
 270 bool MCStreamer::EmitCVFuncIdDirective(unsigned FunctionId) {
 271   return getContext().getCVContext().recordFunctionId(FunctionId);
 272 }
 273
 274 bool MCStreamer::EmitCVInlineSiteIdDirective(unsigned FunctionId,
 275                                              unsigned IAFunc, unsigned IAFile,
 276                                              unsigned IALine, unsigned IACol,
 277                                              SMLoc Loc) {
 278   if (getContext().getCVContext().getCVFunctionInfo(IAFunc) == nullptr) {
 279     getContext().reportError(Loc, "parent function id not introduced by "
 280                                   ".cv_func_id or .cv_inline_site_id");
 281     return true;
 282   }
 283
 284   return getContext().getCVContext().recordInlinedCallSiteId(
 285       FunctionId, IAFunc, IAFile, IALine, IACol);
 286 }
 287
 288 void MCStreamer::EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
 289                                     unsigned Line, unsigned Column,
 290                                     bool PrologueEnd, bool IsStmt,
 291                                     StringRef FileName, SMLoc Loc) {}
 292
 293 bool MCStreamer::checkCVLocSection(unsigned FuncId, unsigned FileNo,
 294                                    SMLoc Loc) {
 295   CodeViewContext &CVC = getContext().getCVContext();
 296   MCCVFunctionInfo *FI = CVC.getCVFunctionInfo(FuncId);
 297   if (!FI) {
 298     getContext().reportError(
 299         Loc, "function id not introduced by .cv_func_id or .cv_inline_site_id");
 300     return false;
 301   }
 302
 303   // Track the section
 304   if (FI->Section == nullptr)
 305     FI->Section = getCurrentSectionOnly();
 306   else if (FI->Section != getCurrentSectionOnly()) {
 307     getContext().reportError(
 308         Loc,
 309         "all .cv_loc directives for a function must be in the same section");
 310     return false;
 311   }
 312   return true;
 313 }
 314
 315 void MCStreamer::EmitCVLinetableDirective(unsigned FunctionId,
 316                                           const MCSymbol *Begin,
 317                                           const MCSymbol *End) {}
 318
 319 void MCStreamer::EmitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
 320                                                 unsigned SourceFileId,
 321                                                 unsigned SourceLineNum,
 322                                                 const MCSymbol *FnStartSym,
 323                                                 const MCSymbol *FnEndSym) {}
 324
 325 void MCStreamer::EmitCVDefRangeDirective(
 326     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
 327     StringRef FixedSizePortion) {}
 328
 329 void MCStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
 330                                      MCSymbol *EHSymbol) {
 331 }
 332
 333 void MCStreamer::InitSections(bool NoExecStack) {
 334   SwitchSection(getContext().getObjectFileInfo()->getTextSection());
 335 }
 336
 337 void MCStreamer::AssignFragment(MCSymbol *Symbol, MCFragment *Fragment) {
 338   assert(Fragment);
 339   Symbol->setFragment(Fragment);
 340
 341   // As we emit symbols into a section, track the order so that they can
 342   // be sorted upon later. Zero is reserved to mean 'unemitted'.
 343   SymbolOrdering[Symbol] = 1 + SymbolOrdering.size();
 344 }
 345
 346 void MCStreamer::EmitLabel(MCSymbol *Symbol, SMLoc Loc) {
 347   Symbol->redefineIfPossible();
 348
 349   if (!Symbol->isUndefined() || Symbol->isVariable())
 350     return getContext().reportError(Loc, "invalid symbol redefinition");
 351
 352   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
 353   assert(getCurrentSectionOnly() && "Cannot emit before setting section!");
 354   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
 355   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
 356
 357   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());
 358
 359   MCTargetStreamer *TS = getTargetStreamer();
 360   if (TS)
 361     TS->emitLabel(Symbol);
 362 }
 363
 364 void MCStreamer::EmitCFISections(bool EH, bool Debug) {
 365   assert(EH || Debug);
 366 }
 367
 368 void MCStreamer::EmitCFIStartProc(bool IsSimple, SMLoc Loc) {
 369   if (hasUnfinishedDwarfFrameInfo())
 370     return getContext().reportError(
 371         Loc, "starting new .cfi frame before finishing the previous one");
 372
 373   MCDwarfFrameInfo Frame;
 374   Frame.IsSimple = IsSimple;
 375   EmitCFIStartProcImpl(Frame);
 376
 377   const MCAsmInfo* MAI = Context.getAsmInfo();
 378   if (MAI) {
 379     for (const MCCFIInstruction& Inst : MAI->getInitialFrameState()) {
 380       if (Inst.getOperation() == MCCFIInstruction::OpDefCfa ||
 381           Inst.getOperation() == MCCFIInstruction::OpDefCfaRegister) {
 382         Frame.CurrentCfaRegister = Inst.getRegister();
 383       }
 384     }
 385   }
 386
 387   DwarfFrameInfos.push_back(Frame);
 388 }
 389
 390 void MCStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
 391 }
 392
 393 void MCStreamer::EmitCFIEndProc() {
 394   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 395   if (!CurFrame)
 396     return;
 397   EmitCFIEndProcImpl(*CurFrame);
 398 }
 399
 400 void MCStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
 401   // Put a dummy non-null value in Frame.End to mark that this frame has been
 402   // closed.
 403   Frame.End = (MCSymbol *)1;
 404 }
 405
 406 MCSymbol *MCStreamer::EmitCFILabel() {
 407   // Return a dummy non-null value so that label fields appear filled in when
 408   // generating textual assembly.
 409   return (MCSymbol *)1;
 410 }
 411
 412 void MCStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
 413   MCSymbol *Label = EmitCFILabel();
 414   MCCFIInstruction Instruction =
 415     MCCFIInstruction::createDefCfa(Label, Register, Offset);
 416   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 417   if (!CurFrame)
 418     return;
 419   CurFrame->Instructions.push_back(Instruction);
 420   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
 421 }
 422
 423 void MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
 424   MCSymbol *Label = EmitCFILabel();
 425   MCCFIInstruction Instruction =
 426     MCCFIInstruction::createDefCfaOffset(Label, Offset);
 427   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 428   if (!CurFrame)
 429     return;
 430   CurFrame->Instructions.push_back(Instruction);
 431 }
 432
 433 void MCStreamer::EmitCFIAdjustCfaOffset(int64_t Adjustment) {
 434   MCSymbol *Label = EmitCFILabel();
 435   MCCFIInstruction Instruction =
 436     MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment);
 437   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 438   if (!CurFrame)
 439     return;
 440   CurFrame->Instructions.push_back(Instruction);
 441 }
 442
 443 void MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
 444   MCSymbol *Label = EmitCFILabel();
 445   MCCFIInstruction Instruction =
 446     MCCFIInstruction::createDefCfaRegister(Label, Register);
 447   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 448   if (!CurFrame)
 449     return;
 450   CurFrame->Instructions.push_back(Instruction);
 451   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
 452 }
 453
 454 void MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
 455   MCSymbol *Label = EmitCFILabel();
 456   MCCFIInstruction Instruction =
 457     MCCFIInstruction::createOffset(Label, Register, Offset);
 458   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 459   if (!CurFrame)
 460     return;
 461   CurFrame->Instructions.push_back(Instruction);
 462 }
 463
 464 void MCStreamer::EmitCFIRelOffset(int64_t Register, int64_t Offset) {
 465   MCSymbol *Label = EmitCFILabel();
 466   MCCFIInstruction Instruction =
 467     MCCFIInstruction::createRelOffset(Label, Register, Offset);
 468   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 469   if (!CurFrame)
 470     return;
 471   CurFrame->Instructions.push_back(Instruction);
 472 }
 473
 474 void MCStreamer::EmitCFIPersonality(const MCSymbol *Sym,
 475                                     unsigned Encoding) {
 476   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 477   if (!CurFrame)
 478     return;
 479   CurFrame->Personality = Sym;
 480   CurFrame->PersonalityEncoding = Encoding;
 481 }
 482
 483 void MCStreamer::EmitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
 484   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 485   if (!CurFrame)
 486     return;
 487   CurFrame->Lsda = Sym;
 488   CurFrame->LsdaEncoding = Encoding;
 489 }
 490
 491 void MCStreamer::EmitCFIRememberState() {
 492   MCSymbol *Label = EmitCFILabel();
 493   MCCFIInstruction Instruction = MCCFIInstruction::createRememberState(Label);
 494   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 495   if (!CurFrame)
 496     return;
 497   CurFrame->Instructions.push_back(Instruction);
 498 }
 499
 500 void MCStreamer::EmitCFIRestoreState() {
 501   // FIXME: Error if there is no matching cfi_remember_state.
 502   MCSymbol *Label = EmitCFILabel();
 503   MCCFIInstruction Instruction = MCCFIInstruction::createRestoreState(Label);
 504   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 505   if (!CurFrame)
 506     return;
 507   CurFrame->Instructions.push_back(Instruction);
 508 }
 509
 510 void MCStreamer::EmitCFISameValue(int64_t Register) {
 511   MCSymbol *Label = EmitCFILabel();
 512   MCCFIInstruction Instruction =
 513     MCCFIInstruction::createSameValue(Label, Register);
 514   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 515   if (!CurFrame)
 516     return;
 517   CurFrame->Instructions.push_back(Instruction);
 518 }
 519
 520 void MCStreamer::EmitCFIRestore(int64_t Register) {
 521   MCSymbol *Label = EmitCFILabel();
 522   MCCFIInstruction Instruction =
 523     MCCFIInstruction::createRestore(Label, Register);
 524   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 525   if (!CurFrame)
 526     return;
 527   CurFrame->Instructions.push_back(Instruction);
 528 }
 529
 530 void MCStreamer::EmitCFIEscape(StringRef Values) {
 531   MCSymbol *Label = EmitCFILabel();
 532   MCCFIInstruction Instruction = MCCFIInstruction::createEscape(Label, Values);
 533   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 534   if (!CurFrame)
 535     return;
 536   CurFrame->Instructions.push_back(Instruction);
 537 }
 538
 539 void MCStreamer::EmitCFIGnuArgsSize(int64_t Size) {
 540   MCSymbol *Label = EmitCFILabel();
 541   MCCFIInstruction Instruction =
 542     MCCFIInstruction::createGnuArgsSize(Label, Size);
 543   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 544   if (!CurFrame)
 545     return;
 546   CurFrame->Instructions.push_back(Instruction);
 547 }
 548
 549 void MCStreamer::EmitCFISignalFrame() {
 550   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 551   if (!CurFrame)
 552     return;
 553   CurFrame->IsSignalFrame = true;
 554 }
 555
 556 void MCStreamer::EmitCFIUndefined(int64_t Register) {
 557   MCSymbol *Label = EmitCFILabel();
 558   MCCFIInstruction Instruction =
 559     MCCFIInstruction::createUndefined(Label, Register);
 560   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 561   if (!CurFrame)
 562     return;
 563   CurFrame->Instructions.push_back(Instruction);
 564 }
 565
 566 void MCStreamer::EmitCFIRegister(int64_t Register1, int64_t Register2) {
 567   MCSymbol *Label = EmitCFILabel();
 568   MCCFIInstruction Instruction =
 569     MCCFIInstruction::createRegister(Label, Register1, Register2);
 570   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 571   if (!CurFrame)
 572     return;
 573   CurFrame->Instructions.push_back(Instruction);
 574 }
 575
 576 void MCStreamer::EmitCFIWindowSave() {
 577   MCSymbol *Label = EmitCFILabel();
 578   MCCFIInstruction Instruction =
 579     MCCFIInstruction::createWindowSave(Label);
 580   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 581   if (!CurFrame)
 582     return;
 583   CurFrame->Instructions.push_back(Instruction);
 584 }
 585
 586 void MCStreamer::EmitCFINegateRAState() {
 587   MCSymbol *Label = EmitCFILabel();
 588   MCCFIInstruction Instruction = MCCFIInstruction::createNegateRAState(Label);
 589   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 590   if (!CurFrame)
 591     return;
 592   CurFrame->Instructions.push_back(Instruction);
 593 }
 594
 595 void MCStreamer::EmitCFIReturnColumn(int64_t Register) {
 596   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
 597   if (!CurFrame)
 598     return;
 599   CurFrame->RAReg = Register;
 600 }
 601
 602 WinEH::FrameInfo *MCStreamer::EnsureValidWinFrameInfo(SMLoc Loc) {
 603   const MCAsmInfo *MAI = Context.getAsmInfo();
 604   if (!MAI->usesWindowsCFI()) {
 605     getContext().reportError(
 606         Loc, ".seh_* directives are not supported on this target");
 607     return nullptr;
 608   }
 609   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End) {
 610     getContext().reportError(
 611         Loc, ".seh_ directive must appear within an active frame");
 612     return nullptr;
 613   }
 614   return CurrentWinFrameInfo;
 615 }
 616
 617 void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc) {
 618   const MCAsmInfo *MAI = Context.getAsmInfo();
 619   if (!MAI->usesWindowsCFI())
 620     return getContext().reportError(
 621         Loc, ".seh_* directives are not supported on this target");
 622   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
 623     getContext().reportError(
 624         Loc, "Starting a function before ending the previous one!");
 625
 626   MCSymbol *StartProc = EmitCFILabel();
 627
 628   WinFrameInfos.emplace_back(
 629       llvm::make_unique<WinEH::FrameInfo>(Symbol, StartProc));
 630   CurrentWinFrameInfo = WinFrameInfos.back().get();
 631   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
 632 }
 633
 634 void MCStreamer::EmitWinCFIEndProc(SMLoc Loc) {
 635   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 636   if (!CurFrame)
 637     return;
 638   if (CurFrame->ChainedParent)
 639     getContext().reportError(Loc, "Not all chained regions terminated!");
 640
 641   MCSymbol *Label = EmitCFILabel();
 642   CurFrame->End = Label;
 643 }
 644
 645 void MCStreamer::EmitWinCFIFuncletOrFuncEnd(SMLoc Loc) {
 646   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 647   if (!CurFrame)
 648     return;
 649   if (CurFrame->ChainedParent)
 650     getContext().reportError(Loc, "Not all chained regions terminated!");
 651
 652   MCSymbol *Label = EmitCFILabel();
 653   CurFrame->FuncletOrFuncEnd = Label;
 654 }
 655
 656 void MCStreamer::EmitWinCFIStartChained(SMLoc Loc) {
 657   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 658   if (!CurFrame)
 659     return;
 660
 661   MCSymbol *StartProc = EmitCFILabel();
 662
 663   WinFrameInfos.emplace_back(llvm::make_unique<WinEH::FrameInfo>(
 664       CurFrame->Function, StartProc, CurFrame));
 665   CurrentWinFrameInfo = WinFrameInfos.back().get();
 666   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
 667 }
 668
 669 void MCStreamer::EmitWinCFIEndChained(SMLoc Loc) {
 670   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 671   if (!CurFrame)
 672     return;
 673   if (!CurFrame->ChainedParent)
 674     return getContext().reportError(
 675         Loc, "End of a chained region outside a chained region!");
 676
 677   MCSymbol *Label = EmitCFILabel();
 678
 679   CurFrame->End = Label;
 680   CurrentWinFrameInfo = const_cast<WinEH::FrameInfo *>(CurFrame->ChainedParent);
 681 }
 682
 683 void MCStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
 684                                   SMLoc Loc) {
 685   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 686   if (!CurFrame)
 687     return;
 688   if (CurFrame->ChainedParent)
 689     return getContext().reportError(
 690         Loc, "Chained unwind areas can't have handlers!");
 691   CurFrame->ExceptionHandler = Sym;
 692   if (!Except && !Unwind)
 693     getContext().reportError(Loc, "Don't know what kind of handler this is!");
 694   if (Unwind)
 695     CurFrame->HandlesUnwind = true;
 696   if (Except)
 697     CurFrame->HandlesExceptions = true;
 698 }
 699
 700 void MCStreamer::EmitWinEHHandlerData(SMLoc Loc) {
 701   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 702   if (!CurFrame)
 703     return;
 704   if (CurFrame->ChainedParent)
 705     getContext().reportError(Loc, "Chained unwind areas can't have handlers!");
 706 }
 707
 708 void MCStreamer::emitCGProfileEntry(const MCSymbolRefExpr *From,
 709                                     const MCSymbolRefExpr *To, uint64_t Count) {
 710 }
 711
 712 static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
 713                                    MCSection *MainCFISec,
 714                                    const MCSection *TextSec) {
 715   // If this is the main .text section, use the main unwind info section.
 716   if (TextSec == Context.getObjectFileInfo()->getTextSection())
 717     return MainCFISec;
 718
 719   const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
 720   auto *MainCFISecCOFF = cast<MCSectionCOFF>(MainCFISec);
 721   unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
 722
 723   // If this section is COMDAT, this unwind section should be COMDAT associative
 724   // with its group.
 725   const MCSymbol *KeySym = nullptr;
 726   if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
 727     KeySym = TextSecCOFF->getCOMDATSymbol();
 728
 729     // In a GNU environment, we can't use associative comdats. Instead, do what
 730     // GCC does, which is to make plain comdat selectany section named like
 731     // ".[px]data$_Z3foov".
 732     if (!Context.getAsmInfo()->hasCOFFAssociativeComdats()) {
 733       std::string SectionName =
 734           (MainCFISecCOFF->getSectionName() + "$" +
 735            TextSecCOFF->getSectionName().split('$').second)
 736               .str();
 737       return Context.getCOFFSection(
 738           SectionName,
 739           MainCFISecCOFF->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT,
 740           MainCFISecCOFF->getKind(), "", COFF::IMAGE_COMDAT_SELECT_ANY);
 741     }
 742   }
 743
 744   return Context.getAssociativeCOFFSection(MainCFISecCOFF, KeySym, UniqueID);
 745 }
 746
 747 MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
 748   return getWinCFISection(getContext(), &NextWinCFIID,
 749                           getContext().getObjectFileInfo()->getPDataSection(),
 750                           TextSec);
 751 }
 752
 753 MCSection *MCStreamer::getAssociatedXDataSection(const MCSection *TextSec) {
 754   return getWinCFISection(getContext(), &NextWinCFIID,
 755                           getContext().getObjectFileInfo()->getXDataSection(),
 756                           TextSec);
 757 }
 758
 759 void MCStreamer::EmitSyntaxDirective() {}
 760
 761 void MCStreamer::EmitWinCFIPushReg(unsigned Register, SMLoc Loc) {
 762   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 763   if (!CurFrame)
 764     return;
 765
 766   MCSymbol *Label = EmitCFILabel();
 767
 768   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(Label, Register);
 769   CurFrame->Instructions.push_back(Inst);
 770 }
 771
 772 void MCStreamer::EmitWinCFISetFrame(unsigned Register, unsigned Offset,
 773                                     SMLoc Loc) {
 774   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 775   if (!CurFrame)
 776     return;
 777   if (CurFrame->LastFrameInst >= 0)
 778     return getContext().reportError(
 779         Loc, "frame register and offset can be set at most once");
 780   if (Offset & 0x0F)
 781     return getContext().reportError(Loc, "offset is not a multiple of 16");
 782   if (Offset > 240)
 783     return getContext().reportError(
 784         Loc, "frame offset must be less than or equal to 240");
 785
 786   MCSymbol *Label = EmitCFILabel();
 787
 788   WinEH::Instruction Inst =
 789       Win64EH::Instruction::SetFPReg(Label, Register, Offset);
 790   CurFrame->LastFrameInst = CurFrame->Instructions.size();
 791   CurFrame->Instructions.push_back(Inst);
 792 }
 793
 794 void MCStreamer::EmitWinCFIAllocStack(unsigned Size, SMLoc Loc) {
 795   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 796   if (!CurFrame)
 797     return;
 798   if (Size == 0)
 799     return getContext().reportError(Loc,
 800                                     "stack allocation size must be non-zero");
 801   if (Size & 7)
 802     return getContext().reportError(
 803         Loc, "stack allocation size is not a multiple of 8");
 804
 805   MCSymbol *Label = EmitCFILabel();
 806
 807   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
 808   CurFrame->Instructions.push_back(Inst);
 809 }
 810
 811 void MCStreamer::EmitWinCFISaveReg(unsigned Register, unsigned Offset,
 812                                    SMLoc Loc) {
 813   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 814   if (!CurFrame)
 815     return;
 816
 817   if (Offset & 7)
 818     return getContext().reportError(
 819         Loc, "register save offset is not 8 byte aligned");
 820
 821   MCSymbol *Label = EmitCFILabel();
 822
 823   WinEH::Instruction Inst =
 824       Win64EH::Instruction::SaveNonVol(Label, Register, Offset);
 825   CurFrame->Instructions.push_back(Inst);
 826 }
 827
 828 void MCStreamer::EmitWinCFISaveXMM(unsigned Register, unsigned Offset,
 829                                    SMLoc Loc) {
 830   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 831   if (!CurFrame)
 832     return;
 833   if (Offset & 0x0F)
 834     return getContext().reportError(Loc, "offset is not a multiple of 16");
 835
 836   MCSymbol *Label = EmitCFILabel();
 837
 838   WinEH::Instruction Inst =
 839       Win64EH::Instruction::SaveXMM(Label, Register, Offset);
 840   CurFrame->Instructions.push_back(Inst);
 841 }
 842
 843 void MCStreamer::EmitWinCFIPushFrame(bool Code, SMLoc Loc) {
 844   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 845   if (!CurFrame)
 846     return;
 847   if (!CurFrame->Instructions.empty())
 848     return getContext().reportError(
 849         Loc, "If present, PushMachFrame must be the first UOP");
 850
 851   MCSymbol *Label = EmitCFILabel();
 852
 853   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
 854   CurFrame->Instructions.push_back(Inst);
 855 }
 856
 857 void MCStreamer::EmitWinCFIEndProlog(SMLoc Loc) {
 858   WinEH::FrameInfo *CurFrame = EnsureValidWinFrameInfo(Loc);
 859   if (!CurFrame)
 860     return;
 861
 862   MCSymbol *Label = EmitCFILabel();
 863
 864   CurFrame->PrologEnd = Label;
 865 }
 866
 867 void MCStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {}
 868
 869 void MCStreamer::EmitCOFFSymbolIndex(MCSymbol const *Symbol) {}
 870
 871 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {}
 872
 873 void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset) {}
 874
 875 void MCStreamer::EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset) {}
 876
 877 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
 878 /// the specified string in the output .s file.  This capability is
 879 /// indicated by the hasRawTextSupport() predicate.
 880 void MCStreamer::EmitRawTextImpl(StringRef String) {
 881   // This is not llvm_unreachable for the sake of out of tree backend
 882   // developers who may not have assembly streamers and should serve as a
 883   // reminder to not accidentally call EmitRawText in the absence of such.
 884   report_fatal_error("EmitRawText called on an MCStreamer that doesn't support "
 885                      "it (target backend is likely missing an AsmStreamer "
 886                      "implementation)");
 887 }
 888
 889 void MCStreamer::EmitRawText(const Twine &T) {
 890   SmallString<128> Str;
 891   EmitRawTextImpl(T.toStringRef(Str));
 892 }
 893
 894 void MCStreamer::EmitWindowsUnwindTables() {
 895 }
 896
 897 void MCStreamer::Finish() {
 898   if ((!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End) ||
 899       (!WinFrameInfos.empty() && !WinFrameInfos.back()->End)) {
 900     getContext().reportError(SMLoc(), "Unfinished frame!");
 901     return;
 902   }
 903
 904   MCTargetStreamer *TS = getTargetStreamer();
 905   if (TS)
 906     TS->finish();
 907
 908   FinishImpl();
 909 }
 910
 911 void MCStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
 912   visitUsedExpr(*Value);
 913   Symbol->setVariableValue(Value);
 914
 915   MCTargetStreamer *TS = getTargetStreamer();
 916   if (TS)
 917     TS->emitAssignment(Symbol, Value);
 918 }
 919
 920 void MCTargetStreamer::prettyPrintAsm(MCInstPrinter &InstPrinter,
 921                                       raw_ostream &OS, const MCInst &Inst,
 922                                       const MCSubtargetInfo &STI) {
 923   InstPrinter.printInst(&Inst, OS, "", STI);
 924 }
 925
 926 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
 927 }
 928
 929 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
 930   switch (Expr.getKind()) {
 931   case MCExpr::Target:
 932     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
 933     break;
 934
 935   case MCExpr::Constant:
 936     break;
 937
 938   case MCExpr::Binary: {
 939     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
 940     visitUsedExpr(*BE.getLHS());
 941     visitUsedExpr(*BE.getRHS());
 942     break;
 943   }
 944
 945   case MCExpr::SymbolRef:
 946     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
 947     break;
 948
 949   case MCExpr::Unary:
 950     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
 951     break;
 952   }
 953 }
 954
 955 void MCStreamer::EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &) {
 956   // Scan for values.
 957   for (unsigned i = Inst.getNumOperands(); i--;)
 958     if (Inst.getOperand(i).isExpr())
 959       visitUsedExpr(*Inst.getOperand(i).getExpr());
 960 }
 961
 962 void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
 963                                         unsigned Size) {
 964   // Get the Hi-Lo expression.
 965   const MCExpr *Diff =
 966       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
 967                               MCSymbolRefExpr::create(Lo, Context), Context);
 968
 969   const MCAsmInfo *MAI = Context.getAsmInfo();
 970   if (!MAI->doesSetDirectiveSuppressReloc()) {
 971     EmitValue(Diff, Size);
 972     return;
 973   }
 974
 975   // Otherwise, emit with .set (aka assignment).
 976   MCSymbol *SetLabel = Context.createTempSymbol("set", true);
 977   EmitAssignment(SetLabel, Diff);
 978   EmitSymbolValue(SetLabel, Size);
 979 }
 980
 981 void MCStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
 982                                                  const MCSymbol *Lo) {
 983   // Get the Hi-Lo expression.
 984   const MCExpr *Diff =
 985       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
 986                               MCSymbolRefExpr::create(Lo, Context), Context);
 987
 988   EmitULEB128Value(Diff);
 989 }
 990
 991 void MCStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {}
 992 void MCStreamer::EmitThumbFunc(MCSymbol *Func) {}
 993 void MCStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
 994 void MCStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
 995   llvm_unreachable("this directive only supported on COFF targets");
 996 }
 997 void MCStreamer::EndCOFFSymbolDef() {
 998   llvm_unreachable("this directive only supported on COFF targets");
 999 }
1000 void MCStreamer::EmitFileDirective(StringRef Filename) {}
1001 void MCStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
1002   llvm_unreachable("this directive only supported on COFF targets");
1003 }
1004 void MCStreamer::EmitCOFFSymbolType(int Type) {
1005   llvm_unreachable("this directive only supported on COFF targets");
1006 }
1007 void MCStreamer::emitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
1008 void MCStreamer::emitELFSymverDirective(StringRef AliasName,
1009                                         const MCSymbol *Aliasee) {}
1010 void MCStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
1011                                        unsigned ByteAlignment) {}
1012 void MCStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
1013                                 uint64_t Size, unsigned ByteAlignment) {}
1014 void MCStreamer::ChangeSection(MCSection *, const MCExpr *) {}
1015 void MCStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
1016 void MCStreamer::EmitBytes(StringRef Data) {}
1017 void MCStreamer::EmitBinaryData(StringRef Data) { EmitBytes(Data); }
1018 void MCStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) {
1019   visitUsedExpr(*Value);
1020 }
1021 void MCStreamer::EmitULEB128Value(const MCExpr *Value) {}
1022 void MCStreamer::EmitSLEB128Value(const MCExpr *Value) {}
1023 void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc Loc) {}
1024 void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
1025                           SMLoc Loc) {}
1026 void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
1027                                       unsigned ValueSize,
1028                                       unsigned MaxBytesToEmit) {}
1029 void MCStreamer::EmitCodeAlignment(unsigned ByteAlignment,
1030                                    unsigned MaxBytesToEmit) {}
1031 void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value,
1032                                    SMLoc Loc) {}
1033 void MCStreamer::EmitBundleAlignMode(unsigned AlignPow2) {}
1034 void MCStreamer::EmitBundleLock(bool AlignToEnd) {}
1035 void MCStreamer::FinishImpl() {}
1036 void MCStreamer::EmitBundleUnlock() {}
1037
1038 void MCStreamer::SwitchSection(MCSection *Section, const MCExpr *Subsection) {
1039   assert(Section && "Cannot switch to a null section!");
1040   MCSectionSubPair curSection = SectionStack.back().first;
1041   SectionStack.back().second = curSection;
1042   if (MCSectionSubPair(Section, Subsection) != curSection) {
1043     ChangeSection(Section, Subsection);
1044     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
1045     assert(!Section->hasEnded() && "Section already ended");
1046     MCSymbol *Sym = Section->getBeginSymbol();
1047     if (Sym && !Sym->isInSection())
1048       EmitLabel(Sym);
1049   }
1050 }
1051
1052 MCSymbol *MCStreamer::endSection(MCSection *Section) {
1053   // TODO: keep track of the last subsection so that this symbol appears in the
1054   // correct place.
1055   MCSymbol *Sym = Section->getEndSymbol(Context);
1056   if (Sym->isInSection())
1057     return Sym;
1058
1059   SwitchSection(Section);
1060   EmitLabel(Sym);
1061   return Sym;
1062 }
1063
1064 void MCStreamer::EmitVersionForTarget(const Triple &Target,
1065                                       const VersionTuple &SDKVersion) {
1066   if (!Target.isOSBinFormatMachO() || !Target.isOSDarwin())
1067     return;
1068   // Do we even know the version?
1069   if (Target.getOSMajorVersion() == 0)
1070     return;
1071
1072   unsigned Major;
1073   unsigned Minor;
1074   unsigned Update;
1075   MCVersionMinType VersionType;
1076   if (Target.isWatchOS()) {
1077     VersionType = MCVM_WatchOSVersionMin;
1078     Target.getWatchOSVersion(Major, Minor, Update);
1079   } else if (Target.isTvOS()) {
1080     VersionType = MCVM_TvOSVersionMin;
1081     Target.getiOSVersion(Major, Minor, Update);
1082   } else if (Target.isMacOSX()) {
1083     VersionType = MCVM_OSXVersionMin;
1084     if (!Target.getMacOSXVersion(Major, Minor, Update))
1085       Major = 0;
1086   } else {
1087     VersionType = MCVM_IOSVersionMin;
1088     Target.getiOSVersion(Major, Minor, Update);
1089   }
1090   if (Major != 0)
1091     EmitVersionMin(VersionType, Major, Minor, Update, SDKVersion);
1092 }