llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp

   1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
   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 assembles .s files and emits ARM ELF .o object files. Different
  10 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
  11 // delimit regions of data and code.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "ARMRegisterInfo.h"
  16 #include "ARMUnwindOpAsm.h"
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/ADT/SmallString.h"
  19 #include "llvm/ADT/SmallVector.h"
  20 #include "llvm/ADT/StringRef.h"
  21 #include "llvm/ADT/Triple.h"
  22 #include "llvm/ADT/Twine.h"
  23 #include "llvm/BinaryFormat/ELF.h"
  24 #include "llvm/MC/MCAsmBackend.h"
  25 #include "llvm/MC/MCAsmInfo.h"
  26 #include "llvm/MC/MCAssembler.h"
  27 #include "llvm/MC/MCCodeEmitter.h"
  28 #include "llvm/MC/MCContext.h"
  29 #include "llvm/MC/MCELFStreamer.h"
  30 #include "llvm/MC/MCExpr.h"
  31 #include "llvm/MC/MCFixup.h"
  32 #include "llvm/MC/MCFragment.h"
  33 #include "llvm/MC/MCInst.h"
  34 #include "llvm/MC/MCInstPrinter.h"
  35 #include "llvm/MC/MCObjectWriter.h"
  36 #include "llvm/MC/MCRegisterInfo.h"
  37 #include "llvm/MC/MCSection.h"
  38 #include "llvm/MC/MCSectionELF.h"
  39 #include "llvm/MC/MCStreamer.h"
  40 #include "llvm/MC/MCSubtargetInfo.h"
  41 #include "llvm/MC/MCSymbol.h"
  42 #include "llvm/MC/MCSymbolELF.h"
  43 #include "llvm/MC/SectionKind.h"
  44 #include "llvm/Support/ARMBuildAttributes.h"
  45 #include "llvm/Support/ARMEHABI.h"
  46 #include "llvm/Support/Casting.h"
  47 #include "llvm/Support/ErrorHandling.h"
  48 #include "llvm/Support/FormattedStream.h"
  49 #include "llvm/Support/TargetParser.h"
  50 #include "llvm/Support/raw_ostream.h"
  51 #include <algorithm>
  52 #include <cassert>
  53 #include <climits>
  54 #include <cstddef>
  55 #include <cstdint>
  56 #include <string>
  57
  58 using namespace llvm;
  59
  60 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
  61   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
  62          "Invalid personality index");
  63   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
  64 }
  65
  66 namespace {
  67
  68 class ARMELFStreamer;
  69
  70 class ARMTargetAsmStreamer : public ARMTargetStreamer {
  71   formatted_raw_ostream &OS;
  72   MCInstPrinter &InstPrinter;
  73   bool IsVerboseAsm;
  74
  75   void emitFnStart() override;
  76   void emitFnEnd() override;
  77   void emitCantUnwind() override;
  78   void emitPersonality(const MCSymbol *Personality) override;
  79   void emitPersonalityIndex(unsigned Index) override;
  80   void emitHandlerData() override;
  81   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
  82   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
  83   void emitPad(int64_t Offset) override;
  84   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
  85                    bool isVector) override;
  86   void emitUnwindRaw(int64_t Offset,
  87                      const SmallVectorImpl<uint8_t> &Opcodes) override;
  88
  89   void switchVendor(StringRef Vendor) override;
  90   void emitAttribute(unsigned Attribute, unsigned Value) override;
  91   void emitTextAttribute(unsigned Attribute, StringRef String) override;
  92   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
  93                             StringRef StringValue) override;
  94   void emitArch(ARM::ArchKind Arch) override;
  95   void emitArchExtension(uint64_t ArchExt) override;
  96   void emitObjectArch(ARM::ArchKind Arch) override;
  97   void emitFPU(unsigned FPU) override;
  98   void emitInst(uint32_t Inst, char Suffix = '\0') override;
  99   void finishAttributeSection() override;
 100
 101   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
 102   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 103
 104 public:
 105   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
 106                        MCInstPrinter &InstPrinter, bool VerboseAsm);
 107 };
 108
 109 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
 110                                            formatted_raw_ostream &OS,
 111                                            MCInstPrinter &InstPrinter,
 112                                            bool VerboseAsm)
 113     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
 114       IsVerboseAsm(VerboseAsm) {}
 115
 116 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
 117 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
 118 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
 119
 120 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
 121   OS << "\t.personality " << Personality->getName() << '\n';
 122 }
 123
 124 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
 125   OS << "\t.personalityindex " << Index << '\n';
 126 }
 127
 128 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
 129
 130 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
 131                                      int64_t Offset) {
 132   OS << "\t.setfp\t";
 133   InstPrinter.printRegName(OS, FpReg);
 134   OS << ", ";
 135   InstPrinter.printRegName(OS, SpReg);
 136   if (Offset)
 137     OS << ", #" << Offset;
 138   OS << '\n';
 139 }
 140
 141 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
 142   assert((Reg != ARM::SP && Reg != ARM::PC) &&
 143          "the operand of .movsp cannot be either sp or pc");
 144
 145   OS << "\t.movsp\t";
 146   InstPrinter.printRegName(OS, Reg);
 147   if (Offset)
 148     OS << ", #" << Offset;
 149   OS << '\n';
 150 }
 151
 152 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
 153   OS << "\t.pad\t#" << Offset << '\n';
 154 }
 155
 156 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 157                                        bool isVector) {
 158   assert(RegList.size() && "RegList should not be empty");
 159   if (isVector)
 160     OS << "\t.vsave\t{";
 161   else
 162     OS << "\t.save\t{";
 163
 164   InstPrinter.printRegName(OS, RegList[0]);
 165
 166   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
 167     OS << ", ";
 168     InstPrinter.printRegName(OS, RegList[i]);
 169   }
 170
 171   OS << "}\n";
 172 }
 173
 174 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
 175
 176 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 177   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
 178   if (IsVerboseAsm) {
 179     StringRef Name = ELFAttrs::attrTypeAsString(
 180         Attribute, ARMBuildAttrs::getARMAttributeTags());
 181     if (!Name.empty())
 182       OS << "\t@ " << Name;
 183   }
 184   OS << "\n";
 185 }
 186
 187 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
 188                                              StringRef String) {
 189   switch (Attribute) {
 190   case ARMBuildAttrs::CPU_name:
 191     OS << "\t.cpu\t" << String.lower();
 192     break;
 193   default:
 194     OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
 195     if (IsVerboseAsm) {
 196       StringRef Name = ELFAttrs::attrTypeAsString(
 197           Attribute, ARMBuildAttrs::getARMAttributeTags());
 198       if (!Name.empty())
 199         OS << "\t@ " << Name;
 200     }
 201     break;
 202   }
 203   OS << "\n";
 204 }
 205
 206 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
 207                                                 unsigned IntValue,
 208                                                 StringRef StringValue) {
 209   switch (Attribute) {
 210   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
 211   case ARMBuildAttrs::compatibility:
 212     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
 213     if (!StringValue.empty())
 214       OS << ", \"" << StringValue << "\"";
 215     if (IsVerboseAsm)
 216       OS << "\t@ "
 217          << ELFAttrs::attrTypeAsString(Attribute,
 218                                        ARMBuildAttrs::getARMAttributeTags());
 219     break;
 220   }
 221   OS << "\n";
 222 }
 223
 224 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
 225   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
 226 }
 227
 228 void ARMTargetAsmStreamer::emitArchExtension(uint64_t ArchExt) {
 229   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
 230 }
 231
 232 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
 233   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
 234 }
 235
 236 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
 237   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
 238 }
 239
 240 void ARMTargetAsmStreamer::finishAttributeSection() {}
 241
 242 void
 243 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
 244   OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
 245 }
 246
 247 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
 248   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
 249
 250   OS << "\t.thumb_set\t";
 251   Symbol->print(OS, MAI);
 252   OS << ", ";
 253   Value->print(OS, MAI);
 254   OS << '\n';
 255 }
 256
 257 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
 258   OS << "\t.inst";
 259   if (Suffix)
 260     OS << "." << Suffix;
 261   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
 262 }
 263
 264 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
 265                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 266   OS << "\t.unwind_raw " << Offset;
 267   for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
 268                                                 OCE = Opcodes.end();
 269        OCI != OCE; ++OCI)
 270     OS << ", 0x" << Twine::utohexstr(*OCI);
 271   OS << '\n';
 272 }
 273
 274 class ARMTargetELFStreamer : public ARMTargetStreamer {
 275 private:
 276   StringRef CurrentVendor;
 277   unsigned FPU = ARM::FK_INVALID;
 278   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
 279   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
 280
 281   MCSection *AttributeSection = nullptr;
 282
 283   void emitArchDefaultAttributes();
 284   void emitFPUDefaultAttributes();
 285
 286   ARMELFStreamer &getStreamer();
 287
 288   void emitFnStart() override;
 289   void emitFnEnd() override;
 290   void emitCantUnwind() override;
 291   void emitPersonality(const MCSymbol *Personality) override;
 292   void emitPersonalityIndex(unsigned Index) override;
 293   void emitHandlerData() override;
 294   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
 295   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
 296   void emitPad(int64_t Offset) override;
 297   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 298                    bool isVector) override;
 299   void emitUnwindRaw(int64_t Offset,
 300                      const SmallVectorImpl<uint8_t> &Opcodes) override;
 301
 302   void switchVendor(StringRef Vendor) override;
 303   void emitAttribute(unsigned Attribute, unsigned Value) override;
 304   void emitTextAttribute(unsigned Attribute, StringRef String) override;
 305   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
 306                             StringRef StringValue) override;
 307   void emitArch(ARM::ArchKind Arch) override;
 308   void emitObjectArch(ARM::ArchKind Arch) override;
 309   void emitFPU(unsigned FPU) override;
 310   void emitInst(uint32_t Inst, char Suffix = '\0') override;
 311   void finishAttributeSection() override;
 312   void emitLabel(MCSymbol *Symbol) override;
 313
 314   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
 315   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 316
 317   // Reset state between object emissions
 318   void reset() override;
 319
 320 public:
 321   ARMTargetELFStreamer(MCStreamer &S)
 322     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
 323 };
 324
 325 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
 326 /// the appropriate points in the object files. These symbols are defined in the
 327 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
 328 ///
 329 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
 330 /// region of ARM code, Thumb code or data in a section. In practice, this
 331 /// emission does not rely on explicit assembler directives but on inherent
 332 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
 333 /// r0, r0, r0" an instruction).
 334 ///
 335 /// As a result this system is orthogonal to the DataRegion infrastructure used
 336 /// by MachO. Beware!
 337 class ARMELFStreamer : public MCELFStreamer {
 338 public:
 339   friend class ARMTargetELFStreamer;
 340
 341   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
 342                  std::unique_ptr<MCObjectWriter> OW,
 343                  std::unique_ptr<MCCodeEmitter> Emitter, bool IsThumb,
 344                  bool IsAndroid)
 345       : MCELFStreamer(Context, std::move(TAB), std::move(OW),
 346                       std::move(Emitter)),
 347         IsThumb(IsThumb), IsAndroid(IsAndroid) {
 348     EHReset();
 349   }
 350
 351   ~ARMELFStreamer() override = default;
 352
 353   void finishImpl() override;
 354
 355   // ARM exception handling directives
 356   void emitFnStart();
 357   void emitFnEnd();
 358   void emitCantUnwind();
 359   void emitPersonality(const MCSymbol *Per);
 360   void emitPersonalityIndex(unsigned index);
 361   void emitHandlerData();
 362   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
 363   void emitMovSP(unsigned Reg, int64_t Offset = 0);
 364   void emitPad(int64_t Offset);
 365   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
 366   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
 367   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
 368                 SMLoc Loc) override {
 369     emitDataMappingSymbol();
 370     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
 371   }
 372
 373   void changeSection(MCSection *Section, const MCExpr *Subsection) override {
 374     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
 375     MCELFStreamer::changeSection(Section, Subsection);
 376     auto LastMappingSymbol = LastMappingSymbols.find(Section);
 377     if (LastMappingSymbol != LastMappingSymbols.end()) {
 378       LastEMSInfo = std::move(LastMappingSymbol->second);
 379       return;
 380     }
 381     LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
 382   }
 383
 384   /// This function is the one used to emit instruction data into the ELF
 385   /// streamer. We override it to add the appropriate mapping symbol if
 386   /// necessary.
 387   void emitInstruction(const MCInst &Inst,
 388                        const MCSubtargetInfo &STI) override {
 389     if (IsThumb)
 390       EmitThumbMappingSymbol();
 391     else
 392       EmitARMMappingSymbol();
 393
 394     MCELFStreamer::emitInstruction(Inst, STI);
 395   }
 396
 397   void emitInst(uint32_t Inst, char Suffix) {
 398     unsigned Size;
 399     char Buffer[4];
 400     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
 401
 402     switch (Suffix) {
 403     case '\0':
 404       Size = 4;
 405
 406       assert(!IsThumb);
 407       EmitARMMappingSymbol();
 408       for (unsigned II = 0, IE = Size; II != IE; II++) {
 409         const unsigned I = LittleEndian ? (Size - II - 1) : II;
 410         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
 411       }
 412
 413       break;
 414     case 'n':
 415     case 'w':
 416       Size = (Suffix == 'n' ? 2 : 4);
 417
 418       assert(IsThumb);
 419       EmitThumbMappingSymbol();
 420       // Thumb wide instructions are emitted as a pair of 16-bit words of the
 421       // appropriate endianness.
 422       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
 423         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
 424         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
 425         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
 426         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
 427       }
 428
 429       break;
 430     default:
 431       llvm_unreachable("Invalid Suffix");
 432     }
 433
 434     MCELFStreamer::emitBytes(StringRef(Buffer, Size));
 435   }
 436
 437   /// This is one of the functions used to emit data into an ELF section, so the
 438   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 439   /// necessary.
 440   void emitBytes(StringRef Data) override {
 441     emitDataMappingSymbol();
 442     MCELFStreamer::emitBytes(Data);
 443   }
 444
 445   void FlushPendingMappingSymbol() {
 446     if (!LastEMSInfo->hasInfo())
 447       return;
 448     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 449     EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
 450     EMS->resetInfo();
 451   }
 452
 453   /// This is one of the functions used to emit data into an ELF section, so the
 454   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 455   /// necessary.
 456   void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
 457     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
 458       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
 459         getContext().reportError(Loc, "relocated expression must be 32-bit");
 460         return;
 461       }
 462       getOrCreateDataFragment();
 463     }
 464
 465     emitDataMappingSymbol();
 466     MCELFStreamer::emitValueImpl(Value, Size, Loc);
 467   }
 468
 469   void emitAssemblerFlag(MCAssemblerFlag Flag) override {
 470     MCELFStreamer::emitAssemblerFlag(Flag);
 471
 472     switch (Flag) {
 473     case MCAF_SyntaxUnified:
 474       return; // no-op here.
 475     case MCAF_Code16:
 476       IsThumb = true;
 477       return; // Change to Thumb mode
 478     case MCAF_Code32:
 479       IsThumb = false;
 480       return; // Change to ARM mode
 481     case MCAF_Code64:
 482       return;
 483     case MCAF_SubsectionsViaSymbols:
 484       return;
 485     }
 486   }
 487
 488   /// If a label is defined before the .type directive sets the label's type
 489   /// then the label can't be recorded as thumb function when the label is
 490   /// defined. We override emitSymbolAttribute() which is called as part of the
 491   /// parsing of .type so that if the symbol has already been defined we can
 492   /// record the label as Thumb. FIXME: there is a corner case where the state
 493   /// is changed in between the label definition and the .type directive, this
 494   /// is not expected to occur in practice and handling it would require the
 495   /// backend to track IsThumb for every label.
 496   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
 497     bool Val = MCELFStreamer::emitSymbolAttribute(Symbol, Attribute);
 498
 499     if (!IsThumb)
 500       return Val;
 501
 502     unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
 503     if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC) &&
 504         Symbol->isDefined())
 505       getAssembler().setIsThumbFunc(Symbol);
 506
 507     return Val;
 508   };
 509
 510 private:
 511   enum ElfMappingSymbol {
 512     EMS_None,
 513     EMS_ARM,
 514     EMS_Thumb,
 515     EMS_Data
 516   };
 517
 518   struct ElfMappingSymbolInfo {
 519     explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
 520         : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
 521     void resetInfo() {
 522       F = nullptr;
 523       Offset = 0;
 524     }
 525     bool hasInfo() { return F != nullptr; }
 526     SMLoc Loc;
 527     MCFragment *F;
 528     uint64_t Offset;
 529     ElfMappingSymbol State;
 530   };
 531
 532   void emitDataMappingSymbol() {
 533     if (LastEMSInfo->State == EMS_Data)
 534       return;
 535     else if (LastEMSInfo->State == EMS_None) {
 536       // This is a tentative symbol, it won't really be emitted until it's
 537       // actually needed.
 538       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 539       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
 540       if (!DF)
 541         return;
 542       EMS->Loc = SMLoc();
 543       EMS->F = getCurrentFragment();
 544       EMS->Offset = DF->getContents().size();
 545       LastEMSInfo->State = EMS_Data;
 546       return;
 547     }
 548     EmitMappingSymbol("$d");
 549     LastEMSInfo->State = EMS_Data;
 550   }
 551
 552   void EmitThumbMappingSymbol() {
 553     if (LastEMSInfo->State == EMS_Thumb)
 554       return;
 555     FlushPendingMappingSymbol();
 556     EmitMappingSymbol("$t");
 557     LastEMSInfo->State = EMS_Thumb;
 558   }
 559
 560   void EmitARMMappingSymbol() {
 561     if (LastEMSInfo->State == EMS_ARM)
 562       return;
 563     FlushPendingMappingSymbol();
 564     EmitMappingSymbol("$a");
 565     LastEMSInfo->State = EMS_ARM;
 566   }
 567
 568   void EmitMappingSymbol(StringRef Name) {
 569     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
 570         Name + "." + Twine(MappingSymbolCounter++)));
 571     emitLabel(Symbol);
 572
 573     Symbol->setType(ELF::STT_NOTYPE);
 574     Symbol->setBinding(ELF::STB_LOCAL);
 575   }
 576
 577   void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
 578                          uint64_t Offset) {
 579     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
 580         Name + "." + Twine(MappingSymbolCounter++)));
 581     emitLabelAtPos(Symbol, Loc, F, Offset);
 582     Symbol->setType(ELF::STT_NOTYPE);
 583     Symbol->setBinding(ELF::STB_LOCAL);
 584   }
 585
 586   void emitThumbFunc(MCSymbol *Func) override {
 587     getAssembler().setIsThumbFunc(Func);
 588     emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
 589   }
 590
 591   // Helper functions for ARM exception handling directives
 592   void EHReset();
 593
 594   // Reset state between object emissions
 595   void reset() override;
 596
 597   void EmitPersonalityFixup(StringRef Name);
 598   void FlushPendingOffset();
 599   void FlushUnwindOpcodes(bool NoHandlerData);
 600
 601   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
 602                          SectionKind Kind, const MCSymbol &Fn);
 603   void SwitchToExTabSection(const MCSymbol &FnStart);
 604   void SwitchToExIdxSection(const MCSymbol &FnStart);
 605
 606   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
 607
 608   bool IsThumb;
 609   bool IsAndroid;
 610   int64_t MappingSymbolCounter = 0;
 611
 612   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
 613       LastMappingSymbols;
 614
 615   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
 616
 617   // ARM Exception Handling Frame Information
 618   MCSymbol *ExTab;
 619   MCSymbol *FnStart;
 620   const MCSymbol *Personality;
 621   unsigned PersonalityIndex;
 622   unsigned FPReg; // Frame pointer register
 623   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
 624   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
 625   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
 626   bool UsedFP;
 627   bool CantUnwind;
 628   SmallVector<uint8_t, 64> Opcodes;
 629   UnwindOpcodeAssembler UnwindOpAsm;
 630 };
 631
 632 } // end anonymous namespace
 633
 634 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
 635   return static_cast<ARMELFStreamer &>(Streamer);
 636 }
 637
 638 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
 639 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
 640 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
 641
 642 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
 643   getStreamer().emitPersonality(Personality);
 644 }
 645
 646 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
 647   getStreamer().emitPersonalityIndex(Index);
 648 }
 649
 650 void ARMTargetELFStreamer::emitHandlerData() {
 651   getStreamer().emitHandlerData();
 652 }
 653
 654 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
 655                                      int64_t Offset) {
 656   getStreamer().emitSetFP(FpReg, SpReg, Offset);
 657 }
 658
 659 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
 660   getStreamer().emitMovSP(Reg, Offset);
 661 }
 662
 663 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
 664   getStreamer().emitPad(Offset);
 665 }
 666
 667 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 668                                        bool isVector) {
 669   getStreamer().emitRegSave(RegList, isVector);
 670 }
 671
 672 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
 673                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 674   getStreamer().emitUnwindRaw(Offset, Opcodes);
 675 }
 676
 677 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
 678   assert(!Vendor.empty() && "Vendor cannot be empty.");
 679
 680   if (CurrentVendor == Vendor)
 681     return;
 682
 683   if (!CurrentVendor.empty())
 684     finishAttributeSection();
 685
 686   assert(getStreamer().Contents.empty() &&
 687          ".ARM.attributes should be flushed before changing vendor");
 688   CurrentVendor = Vendor;
 689
 690 }
 691
 692 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 693   getStreamer().setAttributeItem(Attribute, Value,
 694                                  /* OverwriteExisting= */ true);
 695 }
 696
 697 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
 698                                              StringRef Value) {
 699   getStreamer().setAttributeItem(Attribute, Value,
 700                                  /* OverwriteExisting= */ true);
 701 }
 702
 703 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
 704                                                 unsigned IntValue,
 705                                                 StringRef StringValue) {
 706   getStreamer().setAttributeItems(Attribute, IntValue, StringValue,
 707                                   /* OverwriteExisting= */ true);
 708 }
 709
 710 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
 711   Arch = Value;
 712 }
 713
 714 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
 715   EmittedArch = Value;
 716 }
 717
 718 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
 719   using namespace ARMBuildAttrs;
 720   ARMELFStreamer &S = getStreamer();
 721
 722   S.setAttributeItem(CPU_name, ARM::getCPUAttr(Arch), false);
 723
 724   if (EmittedArch == ARM::ArchKind::INVALID)
 725     S.setAttributeItem(CPU_arch, ARM::getArchAttr(Arch), false);
 726   else
 727     S.setAttributeItem(CPU_arch, ARM::getArchAttr(EmittedArch), false);
 728
 729   switch (Arch) {
 730   case ARM::ArchKind::ARMV2:
 731   case ARM::ArchKind::ARMV2A:
 732   case ARM::ArchKind::ARMV3:
 733   case ARM::ArchKind::ARMV3M:
 734   case ARM::ArchKind::ARMV4:
 735     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 736     break;
 737
 738   case ARM::ArchKind::ARMV4T:
 739   case ARM::ArchKind::ARMV5T:
 740   case ARM::ArchKind::XSCALE:
 741   case ARM::ArchKind::ARMV5TE:
 742   case ARM::ArchKind::ARMV6:
 743     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 744     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 745     break;
 746
 747   case ARM::ArchKind::ARMV6T2:
 748     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 749     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 750     break;
 751
 752   case ARM::ArchKind::ARMV6K:
 753   case ARM::ArchKind::ARMV6KZ:
 754     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 755     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 756     S.setAttributeItem(Virtualization_use, AllowTZ, false);
 757     break;
 758
 759   case ARM::ArchKind::ARMV6M:
 760     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 761     break;
 762
 763   case ARM::ArchKind::ARMV7A:
 764     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 765     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 766     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 767     break;
 768
 769   case ARM::ArchKind::ARMV7R:
 770     S.setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
 771     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 772     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 773     break;
 774
 775   case ARM::ArchKind::ARMV7EM:
 776   case ARM::ArchKind::ARMV7M:
 777     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 778     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 779     break;
 780
 781   case ARM::ArchKind::ARMV8A:
 782   case ARM::ArchKind::ARMV8_1A:
 783   case ARM::ArchKind::ARMV8_2A:
 784   case ARM::ArchKind::ARMV8_3A:
 785   case ARM::ArchKind::ARMV8_4A:
 786   case ARM::ArchKind::ARMV8_5A:
 787   case ARM::ArchKind::ARMV8_6A:
 788     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 789     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 790     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 791     S.setAttributeItem(MPextension_use, Allowed, false);
 792     S.setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
 793     break;
 794
 795   case ARM::ArchKind::ARMV8MBaseline:
 796   case ARM::ArchKind::ARMV8MMainline:
 797     S.setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
 798     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 799     break;
 800
 801   case ARM::ArchKind::IWMMXT:
 802     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 803     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 804     S.setAttributeItem(WMMX_arch, AllowWMMXv1, false);
 805     break;
 806
 807   case ARM::ArchKind::IWMMXT2:
 808     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 809     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 810     S.setAttributeItem(WMMX_arch, AllowWMMXv2, false);
 811     break;
 812
 813   default:
 814     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
 815     break;
 816   }
 817 }
 818
 819 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
 820   FPU = Value;
 821 }
 822
 823 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
 824   ARMELFStreamer &S = getStreamer();
 825
 826   switch (FPU) {
 827   case ARM::FK_VFP:
 828   case ARM::FK_VFPV2:
 829     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv2,
 830                        /* OverwriteExisting= */ false);
 831     break;
 832
 833   case ARM::FK_VFPV3:
 834     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 835                        /* OverwriteExisting= */ false);
 836     break;
 837
 838   case ARM::FK_VFPV3_FP16:
 839     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 840                        /* OverwriteExisting= */ false);
 841     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 842                        /* OverwriteExisting= */ false);
 843     break;
 844
 845   case ARM::FK_VFPV3_D16:
 846     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 847                        /* OverwriteExisting= */ false);
 848     break;
 849
 850   case ARM::FK_VFPV3_D16_FP16:
 851     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 852                        /* OverwriteExisting= */ false);
 853     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 854                        /* OverwriteExisting= */ false);
 855     break;
 856
 857   case ARM::FK_VFPV3XD:
 858     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 859                        /* OverwriteExisting= */ false);
 860     break;
 861   case ARM::FK_VFPV3XD_FP16:
 862     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 863                        /* OverwriteExisting= */ false);
 864     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 865                        /* OverwriteExisting= */ false);
 866     break;
 867
 868   case ARM::FK_VFPV4:
 869     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
 870                        /* OverwriteExisting= */ false);
 871     break;
 872
 873   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
 874   // as _D16 here.
 875   case ARM::FK_FPV4_SP_D16:
 876   case ARM::FK_VFPV4_D16:
 877     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4B,
 878                        /* OverwriteExisting= */ false);
 879     break;
 880
 881   case ARM::FK_FP_ARMV8:
 882     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
 883                        /* OverwriteExisting= */ false);
 884     break;
 885
 886   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
 887   // uses the FP_ARMV8_D16 build attribute.
 888   case ARM::FK_FPV5_SP_D16:
 889   case ARM::FK_FPV5_D16:
 890     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8B,
 891                        /* OverwriteExisting= */ false);
 892     break;
 893
 894   case ARM::FK_NEON:
 895     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 896                        /* OverwriteExisting= */ false);
 897     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
 898                        ARMBuildAttrs::AllowNeon,
 899                        /* OverwriteExisting= */ false);
 900     break;
 901
 902   case ARM::FK_NEON_FP16:
 903     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 904                        /* OverwriteExisting= */ false);
 905     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
 906                        ARMBuildAttrs::AllowNeon,
 907                        /* OverwriteExisting= */ false);
 908     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 909                        /* OverwriteExisting= */ false);
 910     break;
 911
 912   case ARM::FK_NEON_VFPV4:
 913     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
 914                        /* OverwriteExisting= */ false);
 915     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
 916                        ARMBuildAttrs::AllowNeon2,
 917                        /* OverwriteExisting= */ false);
 918     break;
 919
 920   case ARM::FK_NEON_FP_ARMV8:
 921   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
 922     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
 923                        /* OverwriteExisting= */ false);
 924     // 'Advanced_SIMD_arch' must be emitted not here, but within
 925     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
 926     break;
 927
 928   case ARM::FK_SOFTVFP:
 929   case ARM::FK_NONE:
 930     break;
 931
 932   default:
 933     report_fatal_error("Unknown FPU: " + Twine(FPU));
 934     break;
 935   }
 936 }
 937
 938 void ARMTargetELFStreamer::finishAttributeSection() {
 939   ARMELFStreamer &S = getStreamer();
 940
 941   if (FPU != ARM::FK_INVALID)
 942     emitFPUDefaultAttributes();
 943
 944   if (Arch != ARM::ArchKind::INVALID)
 945     emitArchDefaultAttributes();
 946
 947   if (S.Contents.empty())
 948     return;
 949
 950   auto LessTag = [](const MCELFStreamer::AttributeItem &LHS,
 951                     const MCELFStreamer::AttributeItem &RHS) -> bool {
 952     // The conformance tag must be emitted first when serialised into an
 953     // object file. Specifically, the addenda to the ARM ABI states that
 954     // (2.3.7.4):
 955     //
 956     // "To simplify recognition by consumers in the common case of claiming
 957     // conformity for the whole file, this tag should be emitted first in a
 958     // file-scope sub-subsection of the first public subsection of the
 959     // attributes section."
 960     //
 961     // So it is special-cased in this comparison predicate when the
 962     // attributes are sorted in finishAttributeSection().
 963     return (RHS.Tag != ARMBuildAttrs::conformance) &&
 964            ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
 965   };
 966   llvm::sort(S.Contents, LessTag);
 967
 968   S.emitAttributesSection(CurrentVendor, ".ARM.attributes",
 969                           ELF::SHT_ARM_ATTRIBUTES, AttributeSection);
 970
 971   FPU = ARM::FK_INVALID;
 972 }
 973
 974 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
 975   ARMELFStreamer &Streamer = getStreamer();
 976   if (!Streamer.IsThumb)
 977     return;
 978
 979   Streamer.getAssembler().registerSymbol(*Symbol);
 980   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
 981   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
 982     Streamer.emitThumbFunc(Symbol);
 983 }
 984
 985 void
 986 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
 987   getStreamer().EmitFixup(S, FK_Data_4);
 988 }
 989
 990 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
 991   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
 992     const MCSymbol &Sym = SRE->getSymbol();
 993     if (!Sym.isDefined()) {
 994       getStreamer().emitAssignment(Symbol, Value);
 995       return;
 996     }
 997   }
 998
 999   getStreamer().emitThumbFunc(Symbol);
1000   getStreamer().emitAssignment(Symbol, Value);
1001 }
1002
1003 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1004   getStreamer().emitInst(Inst, Suffix);
1005 }
1006
1007 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1008
1009 void ARMELFStreamer::finishImpl() {
1010   MCTargetStreamer &TS = *getTargetStreamer();
1011   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1012   ATS.finishAttributeSection();
1013
1014   MCELFStreamer::finishImpl();
1015 }
1016
1017 void ARMELFStreamer::reset() {
1018   MCTargetStreamer &TS = *getTargetStreamer();
1019   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1020   ATS.reset();
1021   MappingSymbolCounter = 0;
1022   MCELFStreamer::reset();
1023   LastMappingSymbols.clear();
1024   LastEMSInfo.reset();
1025   // MCELFStreamer clear's the assembler's e_flags. However, for
1026   // arm we manually set the ABI version on streamer creation, so
1027   // do the same here
1028   getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1029 }
1030
1031 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1032                                               unsigned Type,
1033                                               unsigned Flags,
1034                                               SectionKind Kind,
1035                                               const MCSymbol &Fn) {
1036   const MCSectionELF &FnSection =
1037     static_cast<const MCSectionELF &>(Fn.getSection());
1038
1039   // Create the name for new section
1040   StringRef FnSecName(FnSection.getName());
1041   SmallString<128> EHSecName(Prefix);
1042   if (FnSecName != ".text") {
1043     EHSecName += FnSecName;
1044   }
1045
1046   // Get .ARM.extab or .ARM.exidx section
1047   const MCSymbolELF *Group = FnSection.getGroup();
1048   if (Group)
1049     Flags |= ELF::SHF_GROUP;
1050   MCSectionELF *EHSection = getContext().getELFSection(
1051       EHSecName, Type, Flags, 0, Group, /*IsComdat=*/true,
1052       FnSection.getUniqueID(),
1053       static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));
1054
1055   assert(EHSection && "Failed to get the required EH section");
1056
1057   // Switch to .ARM.extab or .ARM.exidx section
1058   SwitchSection(EHSection);
1059   emitCodeAlignment(4);
1060 }
1061
1062 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1063   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1064                     SectionKind::getData(), FnStart);
1065 }
1066
1067 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1068   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1069                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1070                     SectionKind::getData(), FnStart);
1071 }
1072
1073 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1074   MCDataFragment *Frag = getOrCreateDataFragment();
1075   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1076                                               Kind));
1077 }
1078
1079 void ARMELFStreamer::EHReset() {
1080   ExTab = nullptr;
1081   FnStart = nullptr;
1082   Personality = nullptr;
1083   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1084   FPReg = ARM::SP;
1085   FPOffset = 0;
1086   SPOffset = 0;
1087   PendingOffset = 0;
1088   UsedFP = false;
1089   CantUnwind = false;
1090
1091   Opcodes.clear();
1092   UnwindOpAsm.Reset();
1093 }
1094
1095 void ARMELFStreamer::emitFnStart() {
1096   assert(FnStart == nullptr);
1097   FnStart = getContext().createTempSymbol();
1098   emitLabel(FnStart);
1099 }
1100
1101 void ARMELFStreamer::emitFnEnd() {
1102   assert(FnStart && ".fnstart must precedes .fnend");
1103
1104   // Emit unwind opcodes if there is no .handlerdata directive
1105   if (!ExTab && !CantUnwind)
1106     FlushUnwindOpcodes(true);
1107
1108   // Emit the exception index table entry
1109   SwitchToExIdxSection(*FnStart);
1110
1111   // The EHABI requires a dependency preserving R_ARM_NONE relocation to the
1112   // personality routine to protect it from an arbitrary platform's static
1113   // linker garbage collection. We disable this for Android where the unwinder
1114   // is either dynamically linked or directly references the personality
1115   // routine.
1116   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX && !IsAndroid)
1117     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1118
1119   const MCSymbolRefExpr *FnStartRef =
1120     MCSymbolRefExpr::create(FnStart,
1121                             MCSymbolRefExpr::VK_ARM_PREL31,
1122                             getContext());
1123
1124   emitValue(FnStartRef, 4);
1125
1126   if (CantUnwind) {
1127     emitInt32(ARM::EHABI::EXIDX_CANTUNWIND);
1128   } else if (ExTab) {
1129     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1130     const MCSymbolRefExpr *ExTabEntryRef =
1131       MCSymbolRefExpr::create(ExTab,
1132                               MCSymbolRefExpr::VK_ARM_PREL31,
1133                               getContext());
1134     emitValue(ExTabEntryRef, 4);
1135   } else {
1136     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1137     // the second word of exception index table entry.  The size of the unwind
1138     // opcodes should always be 4 bytes.
1139     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1140            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1141     assert(Opcodes.size() == 4u &&
1142            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1143     uint64_t Intval = Opcodes[0] |
1144                       Opcodes[1] << 8 |
1145                       Opcodes[2] << 16 |
1146                       Opcodes[3] << 24;
1147     emitIntValue(Intval, Opcodes.size());
1148   }
1149
1150   // Switch to the section containing FnStart
1151   SwitchSection(&FnStart->getSection());
1152
1153   // Clean exception handling frame information
1154   EHReset();
1155 }
1156
1157 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1158
1159 // Add the R_ARM_NONE fixup at the same position
1160 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1161   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1162
1163   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1164       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1165
1166   visitUsedExpr(*PersonalityRef);
1167   MCDataFragment *DF = getOrCreateDataFragment();
1168   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1169                                             PersonalityRef,
1170                                             MCFixup::getKindForSize(4, false)));
1171 }
1172
1173 void ARMELFStreamer::FlushPendingOffset() {
1174   if (PendingOffset != 0) {
1175     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1176     PendingOffset = 0;
1177   }
1178 }
1179
1180 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1181   // Emit the unwind opcode to restore $sp.
1182   if (UsedFP) {
1183     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1184     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1185     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1186     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1187   } else {
1188     FlushPendingOffset();
1189   }
1190
1191   // Finalize the unwind opcode sequence
1192   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1193
1194   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1195   // section.  Thus, we don't have to create an entry in the .ARM.extab
1196   // section.
1197   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1198     return;
1199
1200   // Switch to .ARM.extab section.
1201   SwitchToExTabSection(*FnStart);
1202
1203   // Create .ARM.extab label for offset in .ARM.exidx
1204   assert(!ExTab);
1205   ExTab = getContext().createTempSymbol();
1206   emitLabel(ExTab);
1207
1208   // Emit personality
1209   if (Personality) {
1210     const MCSymbolRefExpr *PersonalityRef =
1211       MCSymbolRefExpr::create(Personality,
1212                               MCSymbolRefExpr::VK_ARM_PREL31,
1213                               getContext());
1214
1215     emitValue(PersonalityRef, 4);
1216   }
1217
1218   // Emit unwind opcodes
1219   assert((Opcodes.size() % 4) == 0 &&
1220          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1221   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1222     uint64_t Intval = Opcodes[I] |
1223                       Opcodes[I + 1] << 8 |
1224                       Opcodes[I + 2] << 16 |
1225                       Opcodes[I + 3] << 24;
1226     emitInt32(Intval);
1227   }
1228
1229   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1230   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1231   // after the unwind opcodes.  The handler data consists of several 32-bit
1232   // words, and should be terminated by zero.
1233   //
1234   // In case that the .handlerdata directive is not specified by the
1235   // programmer, we should emit zero to terminate the handler data.
1236   if (NoHandlerData && !Personality)
1237     emitInt32(0);
1238 }
1239
1240 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1241
1242 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1243   Personality = Per;
1244   UnwindOpAsm.setPersonality(Per);
1245 }
1246
1247 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1248   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1249   PersonalityIndex = Index;
1250 }
1251
1252 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1253                                int64_t Offset) {
1254   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1255          "the operand of .setfp directive should be either $sp or $fp");
1256
1257   UsedFP = true;
1258   FPReg = NewFPReg;
1259
1260   if (NewSPReg == ARM::SP)
1261     FPOffset = SPOffset + Offset;
1262   else
1263     FPOffset += Offset;
1264 }
1265
1266 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1267   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1268          "the operand of .movsp cannot be either sp or pc");
1269   assert(FPReg == ARM::SP && "current FP must be SP");
1270
1271   FlushPendingOffset();
1272
1273   FPReg = Reg;
1274   FPOffset = SPOffset + Offset;
1275
1276   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1277   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1278 }
1279
1280 void ARMELFStreamer::emitPad(int64_t Offset) {
1281   // Track the change of the $sp offset
1282   SPOffset -= Offset;
1283
1284   // To squash multiple .pad directives, we should delay the unwind opcode
1285   // until the .save, .vsave, .handlerdata, or .fnend directives.
1286   PendingOffset -= Offset;
1287 }
1288
1289 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1290                                  bool IsVector) {
1291   // Collect the registers in the register list
1292   unsigned Count = 0;
1293   uint32_t Mask = 0;
1294   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1295   for (size_t i = 0; i < RegList.size(); ++i) {
1296     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1297     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1298     unsigned Bit = (1u << Reg);
1299     if ((Mask & Bit) == 0) {
1300       Mask |= Bit;
1301       ++Count;
1302     }
1303   }
1304
1305   // Track the change the $sp offset: For the .save directive, the
1306   // corresponding push instruction will decrease the $sp by (4 * Count).
1307   // For the .vsave directive, the corresponding vpush instruction will
1308   // decrease $sp by (8 * Count).
1309   SPOffset -= Count * (IsVector ? 8 : 4);
1310
1311   // Emit the opcode
1312   FlushPendingOffset();
1313   if (IsVector)
1314     UnwindOpAsm.EmitVFPRegSave(Mask);
1315   else
1316     UnwindOpAsm.EmitRegSave(Mask);
1317 }
1318
1319 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1320                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1321   FlushPendingOffset();
1322   SPOffset = SPOffset - Offset;
1323   UnwindOpAsm.EmitRaw(Opcodes);
1324 }
1325
1326 namespace llvm {
1327
1328 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1329                                              formatted_raw_ostream &OS,
1330                                              MCInstPrinter *InstPrint,
1331                                              bool isVerboseAsm) {
1332   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1333 }
1334
1335 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1336   return new ARMTargetStreamer(S);
1337 }
1338
1339 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1340                                                 const MCSubtargetInfo &STI) {
1341   const Triple &TT = STI.getTargetTriple();
1342   if (TT.isOSBinFormatELF())
1343     return new ARMTargetELFStreamer(S);
1344   return new ARMTargetStreamer(S);
1345 }
1346
1347 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1348                                     std::unique_ptr<MCAsmBackend> TAB,
1349                                     std::unique_ptr<MCObjectWriter> OW,
1350                                     std::unique_ptr<MCCodeEmitter> Emitter,
1351                                     bool RelaxAll, bool IsThumb,
1352                                     bool IsAndroid) {
1353   ARMELFStreamer *S =
1354       new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1355                          std::move(Emitter), IsThumb, IsAndroid);
1356   // FIXME: This should eventually end up somewhere else where more
1357   // intelligent flag decisions can be made. For now we are just maintaining
1358   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1359   S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1360
1361   if (RelaxAll)
1362     S->getAssembler().setRelaxAll(true);
1363   return S;
1364 }
1365
1366 } // end namespace llvm