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 "ARMMCTargetDesc.h"
  16 #include "ARMUnwindOpAsm.h"
  17 #include "Utils/ARMBaseInfo.h"
  18 #include "llvm/ADT/DenseMap.h"
  19 #include "llvm/ADT/SmallString.h"
  20 #include "llvm/ADT/SmallVector.h"
  21 #include "llvm/ADT/StringExtras.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/ADT/Twine.h"
  24 #include "llvm/BinaryFormat/ELF.h"
  25 #include "llvm/MC/MCAsmBackend.h"
  26 #include "llvm/MC/MCAsmInfo.h"
  27 #include "llvm/MC/MCAssembler.h"
  28 #include "llvm/MC/MCCodeEmitter.h"
  29 #include "llvm/MC/MCContext.h"
  30 #include "llvm/MC/MCELFObjectWriter.h"
  31 #include "llvm/MC/MCELFStreamer.h"
  32 #include "llvm/MC/MCExpr.h"
  33 #include "llvm/MC/MCFixup.h"
  34 #include "llvm/MC/MCFragment.h"
  35 #include "llvm/MC/MCInst.h"
  36 #include "llvm/MC/MCInstPrinter.h"
  37 #include "llvm/MC/MCObjectFileInfo.h"
  38 #include "llvm/MC/MCObjectWriter.h"
  39 #include "llvm/MC/MCRegisterInfo.h"
  40 #include "llvm/MC/MCSection.h"
  41 #include "llvm/MC/MCSectionELF.h"
  42 #include "llvm/MC/MCStreamer.h"
  43 #include "llvm/MC/MCSubtargetInfo.h"
  44 #include "llvm/MC/MCSymbol.h"
  45 #include "llvm/MC/MCSymbolELF.h"
  46 #include "llvm/MC/SectionKind.h"
  47 #include "llvm/Support/ARMBuildAttributes.h"
  48 #include "llvm/Support/ARMEHABI.h"
  49 #include "llvm/Support/Casting.h"
  50 #include "llvm/Support/ErrorHandling.h"
  51 #include "llvm/Support/FormattedStream.h"
  52 #include "llvm/Support/raw_ostream.h"
  53 #include <cassert>
  54 #include <climits>
  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(MCRegister FpReg, MCRegister SpReg,
  82                  int64_t Offset = 0) override;
  83   void emitMovSP(MCRegister Reg, int64_t Offset = 0) override;
  84   void emitPad(int64_t Offset) override;
  85   void emitRegSave(const SmallVectorImpl<MCRegister> &RegList,
  86                    bool isVector) override;
  87   void emitUnwindRaw(int64_t Offset,
  88                      const SmallVectorImpl<uint8_t> &Opcodes) override;
  89
  90   void switchVendor(StringRef Vendor) override;
  91   void emitAttribute(unsigned Attribute, unsigned Value) override;
  92   void emitTextAttribute(unsigned Attribute, StringRef String) override;
  93   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
  94                             StringRef StringValue) override;
  95   void emitArch(ARM::ArchKind Arch) override;
  96   void emitArchExtension(uint64_t ArchExt) override;
  97   void emitObjectArch(ARM::ArchKind Arch) override;
  98   void emitFPU(ARM::FPUKind FPU) override;
  99   void emitInst(uint32_t Inst, char Suffix = '\0') override;
 100   void finishAttributeSection() override;
 101
 102   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
 103   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 104
 105   void emitARMWinCFIAllocStack(unsigned Size, bool Wide) override;
 106   void emitARMWinCFISaveRegMask(unsigned Mask, bool Wide) override;
 107   void emitARMWinCFISaveSP(unsigned Reg) override;
 108   void emitARMWinCFISaveFRegs(unsigned First, unsigned Last) override;
 109   void emitARMWinCFISaveLR(unsigned Offset) override;
 110   void emitARMWinCFIPrologEnd(bool Fragment) override;
 111   void emitARMWinCFINop(bool Wide) override;
 112   void emitARMWinCFIEpilogStart(unsigned Condition) override;
 113   void emitARMWinCFIEpilogEnd() override;
 114   void emitARMWinCFICustom(unsigned Opcode) override;
 115
 116 public:
 117   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
 118                        MCInstPrinter &InstPrinter);
 119 };
 120
 121 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
 122                                            formatted_raw_ostream &OS,
 123                                            MCInstPrinter &InstPrinter)
 124     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
 125       IsVerboseAsm(S.isVerboseAsm()) {}
 126
 127 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
 128 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
 129 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
 130
 131 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
 132   OS << "\t.personality " << Personality->getName() << '\n';
 133 }
 134
 135 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
 136   OS << "\t.personalityindex " << Index << '\n';
 137 }
 138
 139 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
 140
 141 void ARMTargetAsmStreamer::emitSetFP(MCRegister FpReg, MCRegister SpReg,
 142                                      int64_t Offset) {
 143   OS << "\t.setfp\t";
 144   InstPrinter.printRegName(OS, FpReg);
 145   OS << ", ";
 146   InstPrinter.printRegName(OS, SpReg);
 147   if (Offset)
 148     OS << ", #" << Offset;
 149   OS << '\n';
 150 }
 151
 152 void ARMTargetAsmStreamer::emitMovSP(MCRegister Reg, int64_t Offset) {
 153   assert((Reg != ARM::SP && Reg != ARM::PC) &&
 154          "the operand of .movsp cannot be either sp or pc");
 155
 156   OS << "\t.movsp\t";
 157   InstPrinter.printRegName(OS, Reg);
 158   if (Offset)
 159     OS << ", #" << Offset;
 160   OS << '\n';
 161 }
 162
 163 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
 164   OS << "\t.pad\t#" << Offset << '\n';
 165 }
 166
 167 void ARMTargetAsmStreamer::emitRegSave(
 168     const SmallVectorImpl<MCRegister> &RegList, bool isVector) {
 169   assert(RegList.size() && "RegList should not be empty");
 170   if (isVector)
 171     OS << "\t.vsave\t{";
 172   else
 173     OS << "\t.save\t{";
 174
 175   InstPrinter.printRegName(OS, RegList[0]);
 176
 177   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
 178     OS << ", ";
 179     InstPrinter.printRegName(OS, RegList[i]);
 180   }
 181
 182   OS << "}\n";
 183 }
 184
 185 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
 186
 187 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 188   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
 189   if (IsVerboseAsm) {
 190     StringRef Name = ELFAttrs::attrTypeAsString(
 191         Attribute, ARMBuildAttrs::getARMAttributeTags());
 192     if (!Name.empty())
 193       OS << "\t@ " << Name;
 194   }
 195   OS << "\n";
 196 }
 197
 198 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
 199                                              StringRef String) {
 200   switch (Attribute) {
 201   case ARMBuildAttrs::CPU_name:
 202     OS << "\t.cpu\t" << String.lower();
 203     break;
 204   default:
 205     OS << "\t.eabi_attribute\t" << Attribute << ", \"";
 206     if (Attribute == ARMBuildAttrs::also_compatible_with)
 207       OS.write_escaped(String);
 208     else
 209       OS << String;
 210     OS << "\"";
 211     if (IsVerboseAsm) {
 212       StringRef Name = ELFAttrs::attrTypeAsString(
 213           Attribute, ARMBuildAttrs::getARMAttributeTags());
 214       if (!Name.empty())
 215         OS << "\t@ " << Name;
 216     }
 217     break;
 218   }
 219   OS << "\n";
 220 }
 221
 222 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
 223                                                 unsigned IntValue,
 224                                                 StringRef StringValue) {
 225   switch (Attribute) {
 226   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
 227   case ARMBuildAttrs::compatibility:
 228     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
 229     if (!StringValue.empty())
 230       OS << ", \"" << StringValue << "\"";
 231     if (IsVerboseAsm)
 232       OS << "\t@ "
 233          << ELFAttrs::attrTypeAsString(Attribute,
 234                                        ARMBuildAttrs::getARMAttributeTags());
 235     break;
 236   }
 237   OS << "\n";
 238 }
 239
 240 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
 241   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
 242 }
 243
 244 void ARMTargetAsmStreamer::emitArchExtension(uint64_t ArchExt) {
 245   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
 246 }
 247
 248 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
 249   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
 250 }
 251
 252 void ARMTargetAsmStreamer::emitFPU(ARM::FPUKind FPU) {
 253   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
 254 }
 255
 256 void ARMTargetAsmStreamer::finishAttributeSection() {}
 257
 258 void ARMTargetAsmStreamer::annotateTLSDescriptorSequence(
 259     const MCSymbolRefExpr *S) {
 260   OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
 261 }
 262
 263 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
 264   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
 265
 266   OS << "\t.thumb_set\t";
 267   Symbol->print(OS, MAI);
 268   OS << ", ";
 269   Value->print(OS, MAI);
 270   OS << '\n';
 271 }
 272
 273 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
 274   OS << "\t.inst";
 275   if (Suffix)
 276     OS << "." << Suffix;
 277   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
 278 }
 279
 280 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
 281                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 282   OS << "\t.unwind_raw " << Offset;
 283   for (uint8_t Opcode : Opcodes)
 284     OS << ", 0x" << Twine::utohexstr(Opcode);
 285   OS << '\n';
 286 }
 287
 288 void ARMTargetAsmStreamer::emitARMWinCFIAllocStack(unsigned Size, bool Wide) {
 289   if (Wide)
 290     OS << "\t.seh_stackalloc_w\t" << Size << "\n";
 291   else
 292     OS << "\t.seh_stackalloc\t" << Size << "\n";
 293 }
 294
 295 static void printRegs(formatted_raw_ostream &OS, ListSeparator &LS, int First,
 296                       int Last) {
 297   if (First != Last)
 298     OS << LS << "r" << First << "-r" << Last;
 299   else
 300     OS << LS << "r" << First;
 301 }
 302
 303 void ARMTargetAsmStreamer::emitARMWinCFISaveRegMask(unsigned Mask, bool Wide) {
 304   if (Wide)
 305     OS << "\t.seh_save_regs_w\t";
 306   else
 307     OS << "\t.seh_save_regs\t";
 308   ListSeparator LS;
 309   int First = -1;
 310   OS << "{";
 311   for (int I = 0; I <= 12; I++) {
 312     if (Mask & (1 << I)) {
 313       if (First < 0)
 314         First = I;
 315     } else {
 316       if (First >= 0) {
 317         printRegs(OS, LS, First, I - 1);
 318         First = -1;
 319       }
 320     }
 321   }
 322   if (First >= 0)
 323     printRegs(OS, LS, First, 12);
 324   if (Mask & (1 << 14))
 325     OS << LS << "lr";
 326   OS << "}\n";
 327 }
 328
 329 void ARMTargetAsmStreamer::emitARMWinCFISaveSP(unsigned Reg) {
 330   OS << "\t.seh_save_sp\tr" << Reg << "\n";
 331 }
 332
 333 void ARMTargetAsmStreamer::emitARMWinCFISaveFRegs(unsigned First,
 334                                                   unsigned Last) {
 335   if (First != Last)
 336     OS << "\t.seh_save_fregs\t{d" << First << "-d" << Last << "}\n";
 337   else
 338     OS << "\t.seh_save_fregs\t{d" << First << "}\n";
 339 }
 340
 341 void ARMTargetAsmStreamer::emitARMWinCFISaveLR(unsigned Offset) {
 342   OS << "\t.seh_save_lr\t" << Offset << "\n";
 343 }
 344
 345 void ARMTargetAsmStreamer::emitARMWinCFIPrologEnd(bool Fragment) {
 346   if (Fragment)
 347     OS << "\t.seh_endprologue_fragment\n";
 348   else
 349     OS << "\t.seh_endprologue\n";
 350 }
 351
 352 void ARMTargetAsmStreamer::emitARMWinCFINop(bool Wide) {
 353   if (Wide)
 354     OS << "\t.seh_nop_w\n";
 355   else
 356     OS << "\t.seh_nop\n";
 357 }
 358
 359 void ARMTargetAsmStreamer::emitARMWinCFIEpilogStart(unsigned Condition) {
 360   if (Condition == ARMCC::AL)
 361     OS << "\t.seh_startepilogue\n";
 362   else
 363     OS << "\t.seh_startepilogue_cond\t"
 364        << ARMCondCodeToString(static_cast<ARMCC::CondCodes>(Condition)) << "\n";
 365 }
 366
 367 void ARMTargetAsmStreamer::emitARMWinCFIEpilogEnd() {
 368   OS << "\t.seh_endepilogue\n";
 369 }
 370
 371 void ARMTargetAsmStreamer::emitARMWinCFICustom(unsigned Opcode) {
 372   int I;
 373   for (I = 3; I > 0; I--)
 374     if (Opcode & (0xffu << (8 * I)))
 375       break;
 376   ListSeparator LS;
 377   OS << "\t.seh_custom\t";
 378   for (; I >= 0; I--)
 379     OS << LS << ((Opcode >> (8 * I)) & 0xff);
 380   OS << "\n";
 381 }
 382
 383 class ARMTargetELFStreamer : public ARMTargetStreamer {
 384 private:
 385   StringRef CurrentVendor;
 386   ARM::FPUKind FPU = ARM::FK_INVALID;
 387   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
 388   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
 389
 390   MCSection *AttributeSection = nullptr;
 391
 392   void emitArchDefaultAttributes();
 393   void emitFPUDefaultAttributes();
 394
 395   ARMELFStreamer &getStreamer();
 396
 397   void emitFnStart() override;
 398   void emitFnEnd() override;
 399   void emitCantUnwind() override;
 400   void emitPersonality(const MCSymbol *Personality) override;
 401   void emitPersonalityIndex(unsigned Index) override;
 402   void emitHandlerData() override;
 403   void emitSetFP(MCRegister FpReg, MCRegister SpReg,
 404                  int64_t Offset = 0) override;
 405   void emitMovSP(MCRegister Reg, int64_t Offset = 0) override;
 406   void emitPad(int64_t Offset) override;
 407   void emitRegSave(const SmallVectorImpl<MCRegister> &RegList,
 408                    bool isVector) override;
 409   void emitUnwindRaw(int64_t Offset,
 410                      const SmallVectorImpl<uint8_t> &Opcodes) override;
 411
 412   void switchVendor(StringRef Vendor) override;
 413   void emitAttribute(unsigned Attribute, unsigned Value) override;
 414   void emitTextAttribute(unsigned Attribute, StringRef String) override;
 415   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
 416                             StringRef StringValue) override;
 417   void emitArch(ARM::ArchKind Arch) override;
 418   void emitObjectArch(ARM::ArchKind Arch) override;
 419   void emitFPU(ARM::FPUKind FPU) override;
 420   void emitInst(uint32_t Inst, char Suffix = '\0') override;
 421   void finishAttributeSection() override;
 422   void emitLabel(MCSymbol *Symbol) override;
 423
 424   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
 425   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 426
 427   // Reset state between object emissions
 428   void reset() override;
 429
 430   void finish() override;
 431
 432 public:
 433   ARMTargetELFStreamer(MCStreamer &S)
 434     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
 435 };
 436
 437 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
 438 /// the appropriate points in the object files. These symbols are defined in the
 439 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
 440 ///
 441 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
 442 /// region of ARM code, Thumb code or data in a section. In practice, this
 443 /// emission does not rely on explicit assembler directives but on inherent
 444 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
 445 /// r0, r0, r0" an instruction).
 446 ///
 447 /// As a result this system is orthogonal to the DataRegion infrastructure used
 448 /// by MachO. Beware!
 449 class ARMELFStreamer : public MCELFStreamer {
 450 public:
 451   friend class ARMTargetELFStreamer;
 452
 453   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
 454                  std::unique_ptr<MCObjectWriter> OW,
 455                  std::unique_ptr<MCCodeEmitter> Emitter, bool IsThumb,
 456                  bool IsAndroid)
 457       : MCELFStreamer(Context, std::move(TAB), std::move(OW),
 458                       std::move(Emitter)),
 459         IsThumb(IsThumb), IsAndroid(IsAndroid) {
 460     EHReset();
 461   }
 462
 463   ~ARMELFStreamer() override = default;
 464
 465   // ARM exception handling directives
 466   void emitFnStart();
 467   void emitFnEnd();
 468   void emitCantUnwind();
 469   void emitPersonality(const MCSymbol *Per);
 470   void emitPersonalityIndex(unsigned index);
 471   void emitHandlerData();
 472   void emitSetFP(MCRegister NewFpReg, MCRegister NewSpReg, int64_t Offset = 0);
 473   void emitMovSP(MCRegister Reg, int64_t Offset = 0);
 474   void emitPad(int64_t Offset);
 475   void emitRegSave(const SmallVectorImpl<MCRegister> &RegList, bool isVector);
 476   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
 477   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
 478                 SMLoc Loc) override {
 479     emitDataMappingSymbol();
 480     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
 481   }
 482
 483   void changeSection(MCSection *Section, uint32_t Subsection) override {
 484     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
 485     MCELFStreamer::changeSection(Section, Subsection);
 486     auto LastMappingSymbol = LastMappingSymbols.find(Section);
 487     if (LastMappingSymbol != LastMappingSymbols.end()) {
 488       LastEMSInfo = std::move(LastMappingSymbol->second);
 489       return;
 490     }
 491     LastEMSInfo.reset(new ElfMappingSymbolInfo);
 492   }
 493
 494   /// This function is the one used to emit instruction data into the ELF
 495   /// streamer. We override it to add the appropriate mapping symbol if
 496   /// necessary.
 497   void emitInstruction(const MCInst &Inst,
 498                        const MCSubtargetInfo &STI) override {
 499     if (IsThumb)
 500       EmitThumbMappingSymbol();
 501     else
 502       EmitARMMappingSymbol();
 503
 504     MCELFStreamer::emitInstruction(Inst, STI);
 505   }
 506
 507   void emitInst(uint32_t Inst, char Suffix) {
 508     unsigned Size;
 509     char Buffer[4];
 510     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
 511
 512     switch (Suffix) {
 513     case '\0':
 514       Size = 4;
 515
 516       assert(!IsThumb);
 517       EmitARMMappingSymbol();
 518       for (unsigned II = 0, IE = Size; II != IE; II++) {
 519         const unsigned I = LittleEndian ? (Size - II - 1) : II;
 520         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
 521       }
 522
 523       break;
 524     case 'n':
 525     case 'w':
 526       Size = (Suffix == 'n' ? 2 : 4);
 527
 528       assert(IsThumb);
 529       EmitThumbMappingSymbol();
 530       // Thumb wide instructions are emitted as a pair of 16-bit words of the
 531       // appropriate endianness.
 532       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
 533         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
 534         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
 535         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
 536         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
 537       }
 538
 539       break;
 540     default:
 541       llvm_unreachable("Invalid Suffix");
 542     }
 543
 544     MCELFStreamer::emitBytes(StringRef(Buffer, Size));
 545   }
 546
 547   /// This is one of the functions used to emit data into an ELF section, so the
 548   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 549   /// necessary.
 550   void emitBytes(StringRef Data) override {
 551     emitDataMappingSymbol();
 552     MCELFStreamer::emitBytes(Data);
 553   }
 554
 555   void FlushPendingMappingSymbol() {
 556     if (!LastEMSInfo->hasInfo())
 557       return;
 558     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 559     emitMappingSymbol("$d", *EMS->F, EMS->Offset);
 560     EMS->resetInfo();
 561   }
 562
 563   /// This is one of the functions used to emit data into an ELF section, so the
 564   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 565   /// necessary.
 566   void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
 567     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
 568       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
 569         getContext().reportError(Loc, "relocated expression must be 32-bit");
 570         return;
 571       }
 572       getOrCreateDataFragment();
 573     }
 574
 575     emitDataMappingSymbol();
 576     MCELFStreamer::emitValueImpl(Value, Size, Loc);
 577   }
 578
 579   void emitAssemblerFlag(MCAssemblerFlag Flag) override {
 580     MCELFStreamer::emitAssemblerFlag(Flag);
 581
 582     switch (Flag) {
 583     case MCAF_SyntaxUnified:
 584       return; // no-op here.
 585     case MCAF_Code16:
 586       IsThumb = true;
 587       return; // Change to Thumb mode
 588     case MCAF_Code32:
 589       IsThumb = false;
 590       return; // Change to ARM mode
 591     case MCAF_Code64:
 592       return;
 593     case MCAF_SubsectionsViaSymbols:
 594       return;
 595     }
 596   }
 597
 598   /// If a label is defined before the .type directive sets the label's type
 599   /// then the label can't be recorded as thumb function when the label is
 600   /// defined. We override emitSymbolAttribute() which is called as part of the
 601   /// parsing of .type so that if the symbol has already been defined we can
 602   /// record the label as Thumb. FIXME: there is a corner case where the state
 603   /// is changed in between the label definition and the .type directive, this
 604   /// is not expected to occur in practice and handling it would require the
 605   /// backend to track IsThumb for every label.
 606   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
 607     bool Val = MCELFStreamer::emitSymbolAttribute(Symbol, Attribute);
 608
 609     if (!IsThumb)
 610       return Val;
 611
 612     unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
 613     if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC) &&
 614         Symbol->isDefined())
 615       getAssembler().setIsThumbFunc(Symbol);
 616
 617     return Val;
 618   };
 619
 620 private:
 621   enum ElfMappingSymbol {
 622     EMS_None,
 623     EMS_ARM,
 624     EMS_Thumb,
 625     EMS_Data
 626   };
 627
 628   struct ElfMappingSymbolInfo {
 629     void resetInfo() {
 630       F = nullptr;
 631       Offset = 0;
 632     }
 633     bool hasInfo() { return F != nullptr; }
 634     MCDataFragment *F = nullptr;
 635     uint64_t Offset = 0;
 636     ElfMappingSymbol State = EMS_None;
 637   };
 638
 639   void emitDataMappingSymbol() {
 640     if (LastEMSInfo->State == EMS_Data)
 641       return;
 642     else if (LastEMSInfo->State == EMS_None) {
 643       // This is a tentative symbol, it won't really be emitted until it's
 644       // actually needed.
 645       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 646       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
 647       if (!DF)
 648         return;
 649       EMS->F = DF;
 650       EMS->Offset = DF->getContents().size();
 651       LastEMSInfo->State = EMS_Data;
 652       return;
 653     }
 654     EmitMappingSymbol("$d");
 655     LastEMSInfo->State = EMS_Data;
 656   }
 657
 658   void EmitThumbMappingSymbol() {
 659     if (LastEMSInfo->State == EMS_Thumb)
 660       return;
 661     FlushPendingMappingSymbol();
 662     EmitMappingSymbol("$t");
 663     LastEMSInfo->State = EMS_Thumb;
 664   }
 665
 666   void EmitARMMappingSymbol() {
 667     if (LastEMSInfo->State == EMS_ARM)
 668       return;
 669     FlushPendingMappingSymbol();
 670     EmitMappingSymbol("$a");
 671     LastEMSInfo->State = EMS_ARM;
 672   }
 673
 674   void EmitMappingSymbol(StringRef Name) {
 675     auto *Symbol = cast<MCSymbolELF>(getContext().createLocalSymbol(Name));
 676     emitLabel(Symbol);
 677
 678     Symbol->setType(ELF::STT_NOTYPE);
 679     Symbol->setBinding(ELF::STB_LOCAL);
 680   }
 681
 682   void emitMappingSymbol(StringRef Name, MCDataFragment &F, uint64_t Offset) {
 683     auto *Symbol = cast<MCSymbolELF>(getContext().createLocalSymbol(Name));
 684     emitLabelAtPos(Symbol, SMLoc(), F, Offset);
 685     Symbol->setType(ELF::STT_NOTYPE);
 686     Symbol->setBinding(ELF::STB_LOCAL);
 687   }
 688
 689   void emitThumbFunc(MCSymbol *Func) override {
 690     getAssembler().setIsThumbFunc(Func);
 691     emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
 692   }
 693
 694   // Helper functions for ARM exception handling directives
 695   void EHReset();
 696
 697   // Reset state between object emissions
 698   void reset() override;
 699
 700   void EmitPersonalityFixup(StringRef Name);
 701   void FlushPendingOffset();
 702   void FlushUnwindOpcodes(bool NoHandlerData);
 703
 704   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
 705                          SectionKind Kind, const MCSymbol &Fn);
 706   void SwitchToExTabSection(const MCSymbol &FnStart);
 707   void SwitchToExIdxSection(const MCSymbol &FnStart);
 708
 709   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
 710
 711   bool IsThumb;
 712   bool IsAndroid;
 713
 714   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
 715       LastMappingSymbols;
 716
 717   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
 718
 719   // ARM Exception Handling Frame Information
 720   MCSymbol *ExTab;
 721   MCSymbol *FnStart;
 722   const MCSymbol *Personality;
 723   unsigned PersonalityIndex;
 724   MCRegister FPReg; // Frame pointer register
 725   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
 726   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
 727   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
 728   bool UsedFP;
 729   bool CantUnwind;
 730   SmallVector<uint8_t, 64> Opcodes;
 731   UnwindOpcodeAssembler UnwindOpAsm;
 732 };
 733
 734 } // end anonymous namespace
 735
 736 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
 737   return static_cast<ARMELFStreamer &>(Streamer);
 738 }
 739
 740 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
 741 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
 742 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
 743
 744 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
 745   getStreamer().emitPersonality(Personality);
 746 }
 747
 748 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
 749   getStreamer().emitPersonalityIndex(Index);
 750 }
 751
 752 void ARMTargetELFStreamer::emitHandlerData() {
 753   getStreamer().emitHandlerData();
 754 }
 755
 756 void ARMTargetELFStreamer::emitSetFP(MCRegister FpReg, MCRegister SpReg,
 757                                      int64_t Offset) {
 758   getStreamer().emitSetFP(FpReg, SpReg, Offset);
 759 }
 760
 761 void ARMTargetELFStreamer::emitMovSP(MCRegister Reg, int64_t Offset) {
 762   getStreamer().emitMovSP(Reg, Offset);
 763 }
 764
 765 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
 766   getStreamer().emitPad(Offset);
 767 }
 768
 769 void ARMTargetELFStreamer::emitRegSave(
 770     const SmallVectorImpl<MCRegister> &RegList, bool isVector) {
 771   getStreamer().emitRegSave(RegList, isVector);
 772 }
 773
 774 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
 775                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 776   getStreamer().emitUnwindRaw(Offset, Opcodes);
 777 }
 778
 779 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
 780   assert(!Vendor.empty() && "Vendor cannot be empty.");
 781
 782   if (CurrentVendor == Vendor)
 783     return;
 784
 785   if (!CurrentVendor.empty())
 786     finishAttributeSection();
 787
 788   assert(getStreamer().Contents.empty() &&
 789          ".ARM.attributes should be flushed before changing vendor");
 790   CurrentVendor = Vendor;
 791
 792 }
 793
 794 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 795   getStreamer().setAttributeItem(Attribute, Value,
 796                                  /* OverwriteExisting= */ true);
 797 }
 798
 799 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
 800                                              StringRef Value) {
 801   getStreamer().setAttributeItem(Attribute, Value,
 802                                  /* OverwriteExisting= */ true);
 803 }
 804
 805 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
 806                                                 unsigned IntValue,
 807                                                 StringRef StringValue) {
 808   getStreamer().setAttributeItems(Attribute, IntValue, StringValue,
 809                                   /* OverwriteExisting= */ true);
 810 }
 811
 812 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
 813   Arch = Value;
 814 }
 815
 816 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
 817   EmittedArch = Value;
 818 }
 819
 820 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
 821   using namespace ARMBuildAttrs;
 822   ARMELFStreamer &S = getStreamer();
 823
 824   S.setAttributeItem(CPU_name, ARM::getCPUAttr(Arch), false);
 825
 826   if (EmittedArch == ARM::ArchKind::INVALID)
 827     S.setAttributeItem(CPU_arch, ARM::getArchAttr(Arch), false);
 828   else
 829     S.setAttributeItem(CPU_arch, ARM::getArchAttr(EmittedArch), false);
 830
 831   switch (Arch) {
 832   case ARM::ArchKind::ARMV4:
 833     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 834     break;
 835
 836   case ARM::ArchKind::ARMV4T:
 837   case ARM::ArchKind::ARMV5T:
 838   case ARM::ArchKind::XSCALE:
 839   case ARM::ArchKind::ARMV5TE:
 840   case ARM::ArchKind::ARMV6:
 841     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 842     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 843     break;
 844
 845   case ARM::ArchKind::ARMV6T2:
 846     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 847     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 848     break;
 849
 850   case ARM::ArchKind::ARMV6K:
 851   case ARM::ArchKind::ARMV6KZ:
 852     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 853     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 854     S.setAttributeItem(Virtualization_use, AllowTZ, false);
 855     break;
 856
 857   case ARM::ArchKind::ARMV6M:
 858     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 859     break;
 860
 861   case ARM::ArchKind::ARMV7A:
 862     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 863     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 864     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 865     break;
 866
 867   case ARM::ArchKind::ARMV7R:
 868     S.setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
 869     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 870     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 871     break;
 872
 873   case ARM::ArchKind::ARMV7EM:
 874   case ARM::ArchKind::ARMV7M:
 875     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 876     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 877     break;
 878
 879   case ARM::ArchKind::ARMV8A:
 880   case ARM::ArchKind::ARMV8_1A:
 881   case ARM::ArchKind::ARMV8_2A:
 882   case ARM::ArchKind::ARMV8_3A:
 883   case ARM::ArchKind::ARMV8_4A:
 884   case ARM::ArchKind::ARMV8_5A:
 885   case ARM::ArchKind::ARMV8_6A:
 886   case ARM::ArchKind::ARMV8_7A:
 887   case ARM::ArchKind::ARMV8_8A:
 888   case ARM::ArchKind::ARMV8_9A:
 889   case ARM::ArchKind::ARMV9A:
 890   case ARM::ArchKind::ARMV9_1A:
 891   case ARM::ArchKind::ARMV9_2A:
 892   case ARM::ArchKind::ARMV9_3A:
 893   case ARM::ArchKind::ARMV9_4A:
 894   case ARM::ArchKind::ARMV9_5A:
 895   case ARM::ArchKind::ARMV9_6A:
 896     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 897     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 898     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 899     S.setAttributeItem(MPextension_use, Allowed, false);
 900     S.setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
 901     break;
 902
 903   case ARM::ArchKind::ARMV8MBaseline:
 904   case ARM::ArchKind::ARMV8MMainline:
 905     S.setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
 906     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 907     break;
 908
 909   case ARM::ArchKind::IWMMXT:
 910     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 911     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 912     S.setAttributeItem(WMMX_arch, AllowWMMXv1, false);
 913     break;
 914
 915   case ARM::ArchKind::IWMMXT2:
 916     S.setAttributeItem(ARM_ISA_use, Allowed, false);
 917     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
 918     S.setAttributeItem(WMMX_arch, AllowWMMXv2, false);
 919     break;
 920
 921   default:
 922     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
 923     break;
 924   }
 925 }
 926
 927 void ARMTargetELFStreamer::emitFPU(ARM::FPUKind Value) { FPU = Value; }
 928
 929 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
 930   ARMELFStreamer &S = getStreamer();
 931
 932   switch (FPU) {
 933   case ARM::FK_VFP:
 934   case ARM::FK_VFPV2:
 935     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv2,
 936                        /* OverwriteExisting= */ false);
 937     break;
 938
 939   case ARM::FK_VFPV3:
 940     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 941                        /* OverwriteExisting= */ false);
 942     break;
 943
 944   case ARM::FK_VFPV3_FP16:
 945     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
 946                        /* OverwriteExisting= */ false);
 947     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 948                        /* OverwriteExisting= */ false);
 949     break;
 950
 951   case ARM::FK_VFPV3_D16:
 952     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 953                        /* OverwriteExisting= */ false);
 954     break;
 955
 956   case ARM::FK_VFPV3_D16_FP16:
 957     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 958                        /* OverwriteExisting= */ false);
 959     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 960                        /* OverwriteExisting= */ false);
 961     break;
 962
 963   case ARM::FK_VFPV3XD:
 964     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 965                        /* OverwriteExisting= */ false);
 966     break;
 967   case ARM::FK_VFPV3XD_FP16:
 968     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
 969                        /* OverwriteExisting= */ false);
 970     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
 971                        /* OverwriteExisting= */ false);
 972     break;
 973
 974   case ARM::FK_VFPV4:
 975     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
 976                        /* OverwriteExisting= */ false);
 977     break;
 978
 979   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
 980   // as _D16 here.
 981   case ARM::FK_FPV4_SP_D16:
 982   case ARM::FK_VFPV4_D16:
 983     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4B,
 984                        /* OverwriteExisting= */ false);
 985     break;
 986
 987   case ARM::FK_FP_ARMV8:
 988     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
 989                        /* OverwriteExisting= */ false);
 990     break;
 991
 992   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
 993   // uses the FP_ARMV8_D16 build attribute.
 994   case ARM::FK_FPV5_SP_D16:
 995   case ARM::FK_FPV5_D16:
 996   // FPv5 and FP-ARMv8 have the same instructions, so are modeled as one
 997   // FPU, but there are two different names for it depending on the CPU.
 998   case ARM::FK_FP_ARMV8_FULLFP16_SP_D16:
 999   case ARM::FK_FP_ARMV8_FULLFP16_D16:
1000     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8B,
1001                        /* OverwriteExisting= */ false);
1002     break;
1003
1004   case ARM::FK_NEON:
1005     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
1006                        /* OverwriteExisting= */ false);
1007     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1008                        ARMBuildAttrs::AllowNeon,
1009                        /* OverwriteExisting= */ false);
1010     break;
1011
1012   case ARM::FK_NEON_FP16:
1013     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
1014                        /* OverwriteExisting= */ false);
1015     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1016                        ARMBuildAttrs::AllowNeon,
1017                        /* OverwriteExisting= */ false);
1018     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
1019                        /* OverwriteExisting= */ false);
1020     break;
1021
1022   case ARM::FK_NEON_VFPV4:
1023     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
1024                        /* OverwriteExisting= */ false);
1025     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1026                        ARMBuildAttrs::AllowNeon2,
1027                        /* OverwriteExisting= */ false);
1028     break;
1029
1030   case ARM::FK_NEON_FP_ARMV8:
1031   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1032     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
1033                        /* OverwriteExisting= */ false);
1034     // 'Advanced_SIMD_arch' must be emitted not here, but within
1035     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1036     break;
1037
1038   case ARM::FK_SOFTVFP:
1039   case ARM::FK_NONE:
1040     break;
1041
1042   default:
1043     report_fatal_error("Unknown FPU: " + Twine(FPU));
1044     break;
1045   }
1046 }
1047
1048 void ARMTargetELFStreamer::finishAttributeSection() {
1049   ARMELFStreamer &S = getStreamer();
1050
1051   if (FPU != ARM::FK_INVALID)
1052     emitFPUDefaultAttributes();
1053
1054   if (Arch != ARM::ArchKind::INVALID)
1055     emitArchDefaultAttributes();
1056
1057   if (S.Contents.empty())
1058     return;
1059
1060   auto LessTag = [](const MCELFStreamer::AttributeItem &LHS,
1061                     const MCELFStreamer::AttributeItem &RHS) -> bool {
1062     // The conformance tag must be emitted first when serialised into an
1063     // object file. Specifically, the addenda to the ARM ABI states that
1064     // (2.3.7.4):
1065     //
1066     // "To simplify recognition by consumers in the common case of claiming
1067     // conformity for the whole file, this tag should be emitted first in a
1068     // file-scope sub-subsection of the first public subsection of the
1069     // attributes section."
1070     //
1071     // So it is special-cased in this comparison predicate when the
1072     // attributes are sorted in finishAttributeSection().
1073     return (RHS.Tag != ARMBuildAttrs::conformance) &&
1074            ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
1075   };
1076   llvm::sort(S.Contents, LessTag);
1077
1078   S.emitAttributesSection(CurrentVendor, ".ARM.attributes",
1079                           ELF::SHT_ARM_ATTRIBUTES, AttributeSection);
1080
1081   FPU = ARM::FK_INVALID;
1082 }
1083
1084 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1085   ARMELFStreamer &Streamer = getStreamer();
1086   if (!Streamer.IsThumb)
1087     return;
1088
1089   Streamer.getAssembler().registerSymbol(*Symbol);
1090   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1091   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1092     Streamer.emitThumbFunc(Symbol);
1093 }
1094
1095 void ARMTargetELFStreamer::annotateTLSDescriptorSequence(
1096     const MCSymbolRefExpr *S) {
1097   getStreamer().EmitFixup(S, FK_Data_4);
1098 }
1099
1100 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1101   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1102     const MCSymbol &Sym = SRE->getSymbol();
1103     if (!Sym.isDefined()) {
1104       getStreamer().emitAssignment(Symbol, Value);
1105       return;
1106     }
1107   }
1108
1109   getStreamer().emitThumbFunc(Symbol);
1110   getStreamer().emitAssignment(Symbol, Value);
1111 }
1112
1113 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1114   getStreamer().emitInst(Inst, Suffix);
1115 }
1116
1117 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1118
1119 void ARMTargetELFStreamer::finish() {
1120   ARMTargetStreamer::finish();
1121   finishAttributeSection();
1122
1123   // The mix of execute-only and non-execute-only at link time is
1124   // non-execute-only. To avoid the empty implicitly created .text
1125   // section from making the whole .text section non-execute-only, we
1126   // mark it execute-only if it is empty and there is at least one
1127   // execute-only section in the object.
1128   MCContext &Ctx = getStreamer().getContext();
1129   auto &Asm = getStreamer().getAssembler();
1130   if (any_of(Asm, [](const MCSection &Sec) {
1131         return cast<MCSectionELF>(Sec).getFlags() & ELF::SHF_ARM_PURECODE;
1132       })) {
1133     auto *Text =
1134         static_cast<MCSectionELF *>(Ctx.getObjectFileInfo()->getTextSection());
1135     for (auto &F : *Text)
1136       if (auto *DF = dyn_cast<MCDataFragment>(&F))
1137         if (!DF->getContents().empty())
1138           return;
1139     Text->setFlags(Text->getFlags() | ELF::SHF_ARM_PURECODE);
1140   }
1141 }
1142
1143 void ARMELFStreamer::reset() {
1144   MCTargetStreamer &TS = *getTargetStreamer();
1145   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1146   ATS.reset();
1147   MCELFStreamer::reset();
1148   LastMappingSymbols.clear();
1149   LastEMSInfo.reset();
1150   // MCELFStreamer clear's the assembler's e_flags. However, for
1151   // arm we manually set the ABI version on streamer creation, so
1152   // do the same here
1153   getWriter().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1154 }
1155
1156 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1157                                               unsigned Type,
1158                                               unsigned Flags,
1159                                               SectionKind Kind,
1160                                               const MCSymbol &Fn) {
1161   const MCSectionELF &FnSection =
1162     static_cast<const MCSectionELF &>(Fn.getSection());
1163
1164   // Create the name for new section
1165   StringRef FnSecName(FnSection.getName());
1166   SmallString<128> EHSecName(Prefix);
1167   if (FnSecName != ".text") {
1168     EHSecName += FnSecName;
1169   }
1170
1171   // Get .ARM.extab or .ARM.exidx section
1172   const MCSymbolELF *Group = FnSection.getGroup();
1173   if (Group)
1174     Flags |= ELF::SHF_GROUP;
1175   MCSectionELF *EHSection = getContext().getELFSection(
1176       EHSecName, Type, Flags, 0, Group, /*IsComdat=*/true,
1177       FnSection.getUniqueID(),
1178       static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));
1179
1180   assert(EHSection && "Failed to get the required EH section");
1181
1182   // Switch to .ARM.extab or .ARM.exidx section
1183   switchSection(EHSection);
1184   emitValueToAlignment(Align(4), 0, 1, 0);
1185 }
1186
1187 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1188   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1189                     SectionKind::getData(), FnStart);
1190 }
1191
1192 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1193   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1194                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1195                     SectionKind::getData(), FnStart);
1196 }
1197
1198 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1199   MCDataFragment *Frag = getOrCreateDataFragment();
1200   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1201                                               Kind));
1202 }
1203
1204 void ARMELFStreamer::EHReset() {
1205   ExTab = nullptr;
1206   FnStart = nullptr;
1207   Personality = nullptr;
1208   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1209   FPReg = ARM::SP;
1210   FPOffset = 0;
1211   SPOffset = 0;
1212   PendingOffset = 0;
1213   UsedFP = false;
1214   CantUnwind = false;
1215
1216   Opcodes.clear();
1217   UnwindOpAsm.Reset();
1218 }
1219
1220 void ARMELFStreamer::emitFnStart() {
1221   assert(FnStart == nullptr);
1222   FnStart = getContext().createTempSymbol();
1223   emitLabel(FnStart);
1224 }
1225
1226 void ARMELFStreamer::emitFnEnd() {
1227   assert(FnStart && ".fnstart must precedes .fnend");
1228
1229   // Emit unwind opcodes if there is no .handlerdata directive
1230   if (!ExTab && !CantUnwind)
1231     FlushUnwindOpcodes(true);
1232
1233   // Emit the exception index table entry
1234   SwitchToExIdxSection(*FnStart);
1235
1236   // The EHABI requires a dependency preserving R_ARM_NONE relocation to the
1237   // personality routine to protect it from an arbitrary platform's static
1238   // linker garbage collection. We disable this for Android where the unwinder
1239   // is either dynamically linked or directly references the personality
1240   // routine.
1241   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX && !IsAndroid)
1242     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1243
1244   const MCSymbolRefExpr *FnStartRef =
1245     MCSymbolRefExpr::create(FnStart,
1246                             MCSymbolRefExpr::VK_ARM_PREL31,
1247                             getContext());
1248
1249   emitValue(FnStartRef, 4);
1250
1251   if (CantUnwind) {
1252     emitInt32(ARM::EHABI::EXIDX_CANTUNWIND);
1253   } else if (ExTab) {
1254     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1255     const MCSymbolRefExpr *ExTabEntryRef =
1256       MCSymbolRefExpr::create(ExTab,
1257                               MCSymbolRefExpr::VK_ARM_PREL31,
1258                               getContext());
1259     emitValue(ExTabEntryRef, 4);
1260   } else {
1261     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1262     // the second word of exception index table entry.  The size of the unwind
1263     // opcodes should always be 4 bytes.
1264     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1265            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1266     assert(Opcodes.size() == 4u &&
1267            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1268     uint64_t Intval = Opcodes[0] |
1269                       Opcodes[1] << 8 |
1270                       Opcodes[2] << 16 |
1271                       Opcodes[3] << 24;
1272     emitIntValue(Intval, Opcodes.size());
1273   }
1274
1275   // Switch to the section containing FnStart
1276   switchSection(&FnStart->getSection());
1277
1278   // Clean exception handling frame information
1279   EHReset();
1280 }
1281
1282 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1283
1284 // Add the R_ARM_NONE fixup at the same position
1285 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1286   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1287
1288   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1289       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1290
1291   visitUsedExpr(*PersonalityRef);
1292   MCDataFragment *DF = getOrCreateDataFragment();
1293   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1294                                             PersonalityRef,
1295                                             MCFixup::getKindForSize(4, false)));
1296 }
1297
1298 void ARMELFStreamer::FlushPendingOffset() {
1299   if (PendingOffset != 0) {
1300     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1301     PendingOffset = 0;
1302   }
1303 }
1304
1305 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1306   // Emit the unwind opcode to restore $sp.
1307   if (UsedFP) {
1308     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1309     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1310     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1311     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1312   } else {
1313     FlushPendingOffset();
1314   }
1315
1316   // Finalize the unwind opcode sequence
1317   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1318
1319   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1320   // section.  Thus, we don't have to create an entry in the .ARM.extab
1321   // section.
1322   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1323     return;
1324
1325   // Switch to .ARM.extab section.
1326   SwitchToExTabSection(*FnStart);
1327
1328   // Create .ARM.extab label for offset in .ARM.exidx
1329   assert(!ExTab);
1330   ExTab = getContext().createTempSymbol();
1331   emitLabel(ExTab);
1332
1333   // Emit personality
1334   if (Personality) {
1335     const MCSymbolRefExpr *PersonalityRef =
1336       MCSymbolRefExpr::create(Personality,
1337                               MCSymbolRefExpr::VK_ARM_PREL31,
1338                               getContext());
1339
1340     emitValue(PersonalityRef, 4);
1341   }
1342
1343   // Emit unwind opcodes
1344   assert((Opcodes.size() % 4) == 0 &&
1345          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1346   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1347     uint64_t Intval = Opcodes[I] |
1348                       Opcodes[I + 1] << 8 |
1349                       Opcodes[I + 2] << 16 |
1350                       Opcodes[I + 3] << 24;
1351     emitInt32(Intval);
1352   }
1353
1354   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1355   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1356   // after the unwind opcodes.  The handler data consists of several 32-bit
1357   // words, and should be terminated by zero.
1358   //
1359   // In case that the .handlerdata directive is not specified by the
1360   // programmer, we should emit zero to terminate the handler data.
1361   if (NoHandlerData && !Personality)
1362     emitInt32(0);
1363 }
1364
1365 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1366
1367 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1368   Personality = Per;
1369   UnwindOpAsm.setPersonality(Per);
1370 }
1371
1372 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1373   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1374   PersonalityIndex = Index;
1375 }
1376
1377 void ARMELFStreamer::emitSetFP(MCRegister NewFPReg, MCRegister NewSPReg,
1378                                int64_t Offset) {
1379   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1380          "the operand of .setfp directive should be either $sp or $fp");
1381
1382   UsedFP = true;
1383   FPReg = NewFPReg;
1384
1385   if (NewSPReg == ARM::SP)
1386     FPOffset = SPOffset + Offset;
1387   else
1388     FPOffset += Offset;
1389 }
1390
1391 void ARMELFStreamer::emitMovSP(MCRegister Reg, int64_t Offset) {
1392   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1393          "the operand of .movsp cannot be either sp or pc");
1394   assert(FPReg == ARM::SP && "current FP must be SP");
1395
1396   FlushPendingOffset();
1397
1398   FPReg = Reg;
1399   FPOffset = SPOffset + Offset;
1400
1401   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1402   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1403 }
1404
1405 void ARMELFStreamer::emitPad(int64_t Offset) {
1406   // Track the change of the $sp offset
1407   SPOffset -= Offset;
1408
1409   // To squash multiple .pad directives, we should delay the unwind opcode
1410   // until the .save, .vsave, .handlerdata, or .fnend directives.
1411   PendingOffset -= Offset;
1412 }
1413
1414 static std::pair<unsigned, unsigned>
1415 collectHWRegs(const MCRegisterInfo &MRI, unsigned Idx,
1416               const SmallVectorImpl<MCRegister> &RegList, bool IsVector,
1417               uint32_t &Mask_) {
1418   uint32_t Mask = 0;
1419   unsigned Count = 0;
1420   while (Idx > 0) {
1421     MCRegister Reg = RegList[Idx - 1];
1422     if (Reg == ARM::RA_AUTH_CODE)
1423       break;
1424     unsigned RegEnc = MRI.getEncodingValue(Reg);
1425     assert(RegEnc < (IsVector ? 32U : 16U) && "Register out of range");
1426     unsigned Bit = (1u << RegEnc);
1427     if ((Mask & Bit) == 0) {
1428       Mask |= Bit;
1429       ++Count;
1430     }
1431     --Idx;
1432   }
1433
1434   Mask_ = Mask;
1435   return {Idx, Count};
1436 }
1437
1438 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<MCRegister> &RegList,
1439                                  bool IsVector) {
1440   uint32_t Mask;
1441   unsigned Idx, Count;
1442   const MCRegisterInfo &MRI = *getContext().getRegisterInfo();
1443
1444   // Collect the registers in the register list. Issue unwinding instructions in
1445   // three parts: ordinary hardware registers, return address authentication
1446   // code pseudo register, the rest of the registers. The RA PAC is kept in an
1447   // architectural register (usually r12), but we treat it as a special case in
1448   // order to distinguish between that register containing RA PAC or a general
1449   // value.
1450   Idx = RegList.size();
1451   while (Idx > 0) {
1452     std::tie(Idx, Count) = collectHWRegs(MRI, Idx, RegList, IsVector, Mask);
1453     if (Count) {
1454       // Track the change the $sp offset: For the .save directive, the
1455       // corresponding push instruction will decrease the $sp by (4 * Count).
1456       // For the .vsave directive, the corresponding vpush instruction will
1457       // decrease $sp by (8 * Count).
1458       SPOffset -= Count * (IsVector ? 8 : 4);
1459
1460       // Emit the opcode
1461       FlushPendingOffset();
1462       if (IsVector)
1463         UnwindOpAsm.EmitVFPRegSave(Mask);
1464       else
1465         UnwindOpAsm.EmitRegSave(Mask);
1466     } else if (Idx > 0 && RegList[Idx - 1] == ARM::RA_AUTH_CODE) {
1467       --Idx;
1468       SPOffset -= 4;
1469       FlushPendingOffset();
1470       UnwindOpAsm.EmitRegSave(0);
1471     }
1472   }
1473 }
1474
1475 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1476                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1477   FlushPendingOffset();
1478   SPOffset = SPOffset - Offset;
1479   UnwindOpAsm.EmitRaw(Opcodes);
1480 }
1481
1482 namespace llvm {
1483
1484 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1485                                              formatted_raw_ostream &OS,
1486                                              MCInstPrinter *InstPrint) {
1487   return new ARMTargetAsmStreamer(S, OS, *InstPrint);
1488 }
1489
1490 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1491   return new ARMTargetStreamer(S);
1492 }
1493
1494 MCTargetStreamer *createARMObjectTargetELFStreamer(MCStreamer &S) {
1495   return new ARMTargetELFStreamer(S);
1496 }
1497
1498 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1499                                     std::unique_ptr<MCAsmBackend> TAB,
1500                                     std::unique_ptr<MCObjectWriter> OW,
1501                                     std::unique_ptr<MCCodeEmitter> Emitter,
1502                                     bool IsThumb, bool IsAndroid) {
1503   ARMELFStreamer *S =
1504       new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1505                          std::move(Emitter), IsThumb, IsAndroid);
1506   // FIXME: This should eventually end up somewhere else where more
1507   // intelligent flag decisions can be made. For now we are just maintaining
1508   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1509   S->getWriter().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1510
1511   return S;
1512 }
1513
1514 } // end namespace llvm