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/LEB128.h"
  50 #include "llvm/Support/TargetParser.h"
  51 #include "llvm/Support/raw_ostream.h"
  52 #include <algorithm>
  53 #include <cassert>
  54 #include <climits>
  55 #include <cstddef>
  56 #include <cstdint>
  57 #include <string>
  58
  59 using namespace llvm;
  60
  61 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
  62   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
  63          "Invalid personality index");
  64   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
  65 }
  66
  67 namespace {
  68
  69 class ARMELFStreamer;
  70
  71 class ARMTargetAsmStreamer : public ARMTargetStreamer {
  72   formatted_raw_ostream &OS;
  73   MCInstPrinter &InstPrinter;
  74   bool IsVerboseAsm;
  75
  76   void emitFnStart() override;
  77   void emitFnEnd() override;
  78   void emitCantUnwind() override;
  79   void emitPersonality(const MCSymbol *Personality) override;
  80   void emitPersonalityIndex(unsigned Index) override;
  81   void emitHandlerData() override;
  82   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
  83   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
  84   void emitPad(int64_t Offset) override;
  85   void emitRegSave(const SmallVectorImpl<unsigned> &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(unsigned ArchExt) override;
  97   void emitObjectArch(ARM::ArchKind Arch) override;
  98   void emitFPU(unsigned 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 public:
 106   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
 107                        MCInstPrinter &InstPrinter, bool VerboseAsm);
 108 };
 109
 110 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
 111                                            formatted_raw_ostream &OS,
 112                                            MCInstPrinter &InstPrinter,
 113                                            bool VerboseAsm)
 114     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
 115       IsVerboseAsm(VerboseAsm) {}
 116
 117 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
 118 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
 119 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
 120
 121 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
 122   OS << "\t.personality " << Personality->getName() << '\n';
 123 }
 124
 125 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
 126   OS << "\t.personalityindex " << Index << '\n';
 127 }
 128
 129 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
 130
 131 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
 132                                      int64_t Offset) {
 133   OS << "\t.setfp\t";
 134   InstPrinter.printRegName(OS, FpReg);
 135   OS << ", ";
 136   InstPrinter.printRegName(OS, SpReg);
 137   if (Offset)
 138     OS << ", #" << Offset;
 139   OS << '\n';
 140 }
 141
 142 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
 143   assert((Reg != ARM::SP && Reg != ARM::PC) &&
 144          "the operand of .movsp cannot be either sp or pc");
 145
 146   OS << "\t.movsp\t";
 147   InstPrinter.printRegName(OS, Reg);
 148   if (Offset)
 149     OS << ", #" << Offset;
 150   OS << '\n';
 151 }
 152
 153 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
 154   OS << "\t.pad\t#" << Offset << '\n';
 155 }
 156
 157 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 158                                        bool isVector) {
 159   assert(RegList.size() && "RegList should not be empty");
 160   if (isVector)
 161     OS << "\t.vsave\t{";
 162   else
 163     OS << "\t.save\t{";
 164
 165   InstPrinter.printRegName(OS, RegList[0]);
 166
 167   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
 168     OS << ", ";
 169     InstPrinter.printRegName(OS, RegList[i]);
 170   }
 171
 172   OS << "}\n";
 173 }
 174
 175 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
 176
 177 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 178   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
 179   if (IsVerboseAsm) {
 180     StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
 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 = ARMBuildAttrs::AttrTypeAsString(Attribute);
 197       if (!Name.empty())
 198         OS << "\t@ " << Name;
 199     }
 200     break;
 201   }
 202   OS << "\n";
 203 }
 204
 205 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
 206                                                 unsigned IntValue,
 207                                                 StringRef StringValue) {
 208   switch (Attribute) {
 209   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
 210   case ARMBuildAttrs::compatibility:
 211     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
 212     if (!StringValue.empty())
 213       OS << ", \"" << StringValue << "\"";
 214     if (IsVerboseAsm)
 215       OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
 216     break;
 217   }
 218   OS << "\n";
 219 }
 220
 221 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
 222   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
 223 }
 224
 225 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
 226   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
 227 }
 228
 229 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
 230   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
 231 }
 232
 233 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
 234   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
 235 }
 236
 237 void ARMTargetAsmStreamer::finishAttributeSection() {}
 238
 239 void
 240 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
 241   OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
 242 }
 243
 244 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
 245   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
 246
 247   OS << "\t.thumb_set\t";
 248   Symbol->print(OS, MAI);
 249   OS << ", ";
 250   Value->print(OS, MAI);
 251   OS << '\n';
 252 }
 253
 254 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
 255   OS << "\t.inst";
 256   if (Suffix)
 257     OS << "." << Suffix;
 258   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
 259 }
 260
 261 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
 262                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 263   OS << "\t.unwind_raw " << Offset;
 264   for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
 265                                                 OCE = Opcodes.end();
 266        OCI != OCE; ++OCI)
 267     OS << ", 0x" << Twine::utohexstr(*OCI);
 268   OS << '\n';
 269 }
 270
 271 class ARMTargetELFStreamer : public ARMTargetStreamer {
 272 private:
 273   // This structure holds all attributes, accounting for
 274   // their string/numeric value, so we can later emit them
 275   // in declaration order, keeping all in the same vector
 276   struct AttributeItem {
 277     enum {
 278       HiddenAttribute = 0,
 279       NumericAttribute,
 280       TextAttribute,
 281       NumericAndTextAttributes
 282     } Type;
 283     unsigned Tag;
 284     unsigned IntValue;
 285     std::string StringValue;
 286
 287     static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
 288       // The conformance tag must be emitted first when serialised
 289       // into an object file. Specifically, the addenda to the ARM ABI
 290       // states that (2.3.7.4):
 291       //
 292       // "To simplify recognition by consumers in the common case of
 293       // claiming conformity for the whole file, this tag should be
 294       // emitted first in a file-scope sub-subsection of the first
 295       // public subsection of the attributes section."
 296       //
 297       // So it is special-cased in this comparison predicate when the
 298       // attributes are sorted in finishAttributeSection().
 299       return (RHS.Tag != ARMBuildAttrs::conformance) &&
 300              ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
 301     }
 302   };
 303
 304   StringRef CurrentVendor;
 305   unsigned FPU = ARM::FK_INVALID;
 306   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
 307   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
 308   SmallVector<AttributeItem, 64> Contents;
 309
 310   MCSection *AttributeSection = nullptr;
 311
 312   AttributeItem *getAttributeItem(unsigned Attribute) {
 313     for (size_t i = 0; i < Contents.size(); ++i)
 314       if (Contents[i].Tag == Attribute)
 315         return &Contents[i];
 316     return nullptr;
 317   }
 318
 319   void setAttributeItem(unsigned Attribute, unsigned Value,
 320                         bool OverwriteExisting) {
 321     // Look for existing attribute item
 322     if (AttributeItem *Item = getAttributeItem(Attribute)) {
 323       if (!OverwriteExisting)
 324         return;
 325       Item->Type = AttributeItem::NumericAttribute;
 326       Item->IntValue = Value;
 327       return;
 328     }
 329
 330     // Create new attribute item
 331     AttributeItem Item = {
 332       AttributeItem::NumericAttribute,
 333       Attribute,
 334       Value,
 335       StringRef("")
 336     };
 337     Contents.push_back(Item);
 338   }
 339
 340   void setAttributeItem(unsigned Attribute, StringRef Value,
 341                         bool OverwriteExisting) {
 342     // Look for existing attribute item
 343     if (AttributeItem *Item = getAttributeItem(Attribute)) {
 344       if (!OverwriteExisting)
 345         return;
 346       Item->Type = AttributeItem::TextAttribute;
 347       Item->StringValue = Value;
 348       return;
 349     }
 350
 351     // Create new attribute item
 352     AttributeItem Item = {
 353       AttributeItem::TextAttribute,
 354       Attribute,
 355       0,
 356       Value
 357     };
 358     Contents.push_back(Item);
 359   }
 360
 361   void setAttributeItems(unsigned Attribute, unsigned IntValue,
 362                          StringRef StringValue, bool OverwriteExisting) {
 363     // Look for existing attribute item
 364     if (AttributeItem *Item = getAttributeItem(Attribute)) {
 365       if (!OverwriteExisting)
 366         return;
 367       Item->Type = AttributeItem::NumericAndTextAttributes;
 368       Item->IntValue = IntValue;
 369       Item->StringValue = StringValue;
 370       return;
 371     }
 372
 373     // Create new attribute item
 374     AttributeItem Item = {
 375       AttributeItem::NumericAndTextAttributes,
 376       Attribute,
 377       IntValue,
 378       StringValue
 379     };
 380     Contents.push_back(Item);
 381   }
 382
 383   void emitArchDefaultAttributes();
 384   void emitFPUDefaultAttributes();
 385
 386   ARMELFStreamer &getStreamer();
 387
 388   void emitFnStart() override;
 389   void emitFnEnd() override;
 390   void emitCantUnwind() override;
 391   void emitPersonality(const MCSymbol *Personality) override;
 392   void emitPersonalityIndex(unsigned Index) override;
 393   void emitHandlerData() override;
 394   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
 395   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
 396   void emitPad(int64_t Offset) override;
 397   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 398                    bool isVector) override;
 399   void emitUnwindRaw(int64_t Offset,
 400                      const SmallVectorImpl<uint8_t> &Opcodes) override;
 401
 402   void switchVendor(StringRef Vendor) override;
 403   void emitAttribute(unsigned Attribute, unsigned Value) override;
 404   void emitTextAttribute(unsigned Attribute, StringRef String) override;
 405   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
 406                             StringRef StringValue) override;
 407   void emitArch(ARM::ArchKind Arch) override;
 408   void emitObjectArch(ARM::ArchKind Arch) override;
 409   void emitFPU(unsigned FPU) override;
 410   void emitInst(uint32_t Inst, char Suffix = '\0') override;
 411   void finishAttributeSection() override;
 412   void emitLabel(MCSymbol *Symbol) override;
 413
 414   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
 415   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
 416
 417   size_t calculateContentSize() const;
 418
 419   // Reset state between object emissions
 420   void reset() override;
 421
 422 public:
 423   ARMTargetELFStreamer(MCStreamer &S)
 424     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
 425 };
 426
 427 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
 428 /// the appropriate points in the object files. These symbols are defined in the
 429 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
 430 ///
 431 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
 432 /// region of ARM code, Thumb code or data in a section. In practice, this
 433 /// emission does not rely on explicit assembler directives but on inherent
 434 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
 435 /// r0, r0, r0" an instruction).
 436 ///
 437 /// As a result this system is orthogonal to the DataRegion infrastructure used
 438 /// by MachO. Beware!
 439 class ARMELFStreamer : public MCELFStreamer {
 440 public:
 441   friend class ARMTargetELFStreamer;
 442
 443   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
 444                  std::unique_ptr<MCObjectWriter> OW, std::unique_ptr<MCCodeEmitter> Emitter,
 445                  bool IsThumb)
 446       : MCELFStreamer(Context, std::move(TAB), std::move(OW), std::move(Emitter)),
 447         IsThumb(IsThumb) {
 448     EHReset();
 449   }
 450
 451   ~ARMELFStreamer() override = default;
 452
 453   void FinishImpl() override;
 454
 455   // ARM exception handling directives
 456   void emitFnStart();
 457   void emitFnEnd();
 458   void emitCantUnwind();
 459   void emitPersonality(const MCSymbol *Per);
 460   void emitPersonalityIndex(unsigned index);
 461   void emitHandlerData();
 462   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
 463   void emitMovSP(unsigned Reg, int64_t Offset = 0);
 464   void emitPad(int64_t Offset);
 465   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
 466   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
 467   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
 468                 SMLoc Loc) override {
 469     EmitDataMappingSymbol();
 470     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
 471   }
 472
 473   void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
 474     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
 475     MCELFStreamer::ChangeSection(Section, Subsection);
 476     auto LastMappingSymbol = LastMappingSymbols.find(Section);
 477     if (LastMappingSymbol != LastMappingSymbols.end()) {
 478       LastEMSInfo = std::move(LastMappingSymbol->second);
 479       return;
 480     }
 481     LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
 482   }
 483
 484   /// This function is the one used to emit instruction data into the ELF
 485   /// streamer. We override it to add the appropriate mapping symbol if
 486   /// necessary.
 487   void EmitInstruction(const MCInst &Inst,
 488                        const MCSubtargetInfo &STI) override {
 489     if (IsThumb)
 490       EmitThumbMappingSymbol();
 491     else
 492       EmitARMMappingSymbol();
 493
 494     MCELFStreamer::EmitInstruction(Inst, STI);
 495   }
 496
 497   void emitInst(uint32_t Inst, char Suffix) {
 498     unsigned Size;
 499     char Buffer[4];
 500     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
 501
 502     switch (Suffix) {
 503     case '\0':
 504       Size = 4;
 505
 506       assert(!IsThumb);
 507       EmitARMMappingSymbol();
 508       for (unsigned II = 0, IE = Size; II != IE; II++) {
 509         const unsigned I = LittleEndian ? (Size - II - 1) : II;
 510         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
 511       }
 512
 513       break;
 514     case 'n':
 515     case 'w':
 516       Size = (Suffix == 'n' ? 2 : 4);
 517
 518       assert(IsThumb);
 519       EmitThumbMappingSymbol();
 520       // Thumb wide instructions are emitted as a pair of 16-bit words of the
 521       // appropriate endianness.
 522       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
 523         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
 524         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
 525         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
 526         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
 527       }
 528
 529       break;
 530     default:
 531       llvm_unreachable("Invalid Suffix");
 532     }
 533
 534     MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
 535   }
 536
 537   /// This is one of the functions used to emit data into an ELF section, so the
 538   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 539   /// necessary.
 540   void EmitBytes(StringRef Data) override {
 541     EmitDataMappingSymbol();
 542     MCELFStreamer::EmitBytes(Data);
 543   }
 544
 545   void FlushPendingMappingSymbol() {
 546     if (!LastEMSInfo->hasInfo())
 547       return;
 548     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 549     EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
 550     EMS->resetInfo();
 551   }
 552
 553   /// This is one of the functions used to emit data into an ELF section, so the
 554   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
 555   /// necessary.
 556   void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
 557     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
 558       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
 559         getContext().reportError(Loc, "relocated expression must be 32-bit");
 560         return;
 561       }
 562       getOrCreateDataFragment();
 563     }
 564
 565     EmitDataMappingSymbol();
 566     MCELFStreamer::EmitValueImpl(Value, Size, Loc);
 567   }
 568
 569   void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
 570     MCELFStreamer::EmitAssemblerFlag(Flag);
 571
 572     switch (Flag) {
 573     case MCAF_SyntaxUnified:
 574       return; // no-op here.
 575     case MCAF_Code16:
 576       IsThumb = true;
 577       return; // Change to Thumb mode
 578     case MCAF_Code32:
 579       IsThumb = false;
 580       return; // Change to ARM mode
 581     case MCAF_Code64:
 582       return;
 583     case MCAF_SubsectionsViaSymbols:
 584       return;
 585     }
 586   }
 587
 588 private:
 589   enum ElfMappingSymbol {
 590     EMS_None,
 591     EMS_ARM,
 592     EMS_Thumb,
 593     EMS_Data
 594   };
 595
 596   struct ElfMappingSymbolInfo {
 597     explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
 598         : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
 599     void resetInfo() {
 600       F = nullptr;
 601       Offset = 0;
 602     }
 603     bool hasInfo() { return F != nullptr; }
 604     SMLoc Loc;
 605     MCFragment *F;
 606     uint64_t Offset;
 607     ElfMappingSymbol State;
 608   };
 609
 610   void EmitDataMappingSymbol() {
 611     if (LastEMSInfo->State == EMS_Data)
 612       return;
 613     else if (LastEMSInfo->State == EMS_None) {
 614       // This is a tentative symbol, it won't really be emitted until it's
 615       // actually needed.
 616       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
 617       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
 618       if (!DF)
 619         return;
 620       EMS->Loc = SMLoc();
 621       EMS->F = getCurrentFragment();
 622       EMS->Offset = DF->getContents().size();
 623       LastEMSInfo->State = EMS_Data;
 624       return;
 625     }
 626     EmitMappingSymbol("$d");
 627     LastEMSInfo->State = EMS_Data;
 628   }
 629
 630   void EmitThumbMappingSymbol() {
 631     if (LastEMSInfo->State == EMS_Thumb)
 632       return;
 633     FlushPendingMappingSymbol();
 634     EmitMappingSymbol("$t");
 635     LastEMSInfo->State = EMS_Thumb;
 636   }
 637
 638   void EmitARMMappingSymbol() {
 639     if (LastEMSInfo->State == EMS_ARM)
 640       return;
 641     FlushPendingMappingSymbol();
 642     EmitMappingSymbol("$a");
 643     LastEMSInfo->State = EMS_ARM;
 644   }
 645
 646   void EmitMappingSymbol(StringRef Name) {
 647     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
 648         Name + "." + Twine(MappingSymbolCounter++)));
 649     EmitLabel(Symbol);
 650
 651     Symbol->setType(ELF::STT_NOTYPE);
 652     Symbol->setBinding(ELF::STB_LOCAL);
 653     Symbol->setExternal(false);
 654   }
 655
 656   void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
 657                          uint64_t Offset) {
 658     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
 659         Name + "." + Twine(MappingSymbolCounter++)));
 660     EmitLabel(Symbol, Loc, F);
 661     Symbol->setType(ELF::STT_NOTYPE);
 662     Symbol->setBinding(ELF::STB_LOCAL);
 663     Symbol->setExternal(false);
 664     Symbol->setOffset(Offset);
 665   }
 666
 667   void EmitThumbFunc(MCSymbol *Func) override {
 668     getAssembler().setIsThumbFunc(Func);
 669     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
 670   }
 671
 672   // Helper functions for ARM exception handling directives
 673   void EHReset();
 674
 675   // Reset state between object emissions
 676   void reset() override;
 677
 678   void EmitPersonalityFixup(StringRef Name);
 679   void FlushPendingOffset();
 680   void FlushUnwindOpcodes(bool NoHandlerData);
 681
 682   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
 683                          SectionKind Kind, const MCSymbol &Fn);
 684   void SwitchToExTabSection(const MCSymbol &FnStart);
 685   void SwitchToExIdxSection(const MCSymbol &FnStart);
 686
 687   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
 688
 689   bool IsThumb;
 690   int64_t MappingSymbolCounter = 0;
 691
 692   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
 693       LastMappingSymbols;
 694
 695   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
 696
 697   // ARM Exception Handling Frame Information
 698   MCSymbol *ExTab;
 699   MCSymbol *FnStart;
 700   const MCSymbol *Personality;
 701   unsigned PersonalityIndex;
 702   unsigned FPReg; // Frame pointer register
 703   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
 704   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
 705   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
 706   bool UsedFP;
 707   bool CantUnwind;
 708   SmallVector<uint8_t, 64> Opcodes;
 709   UnwindOpcodeAssembler UnwindOpAsm;
 710 };
 711
 712 } // end anonymous namespace
 713
 714 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
 715   return static_cast<ARMELFStreamer &>(Streamer);
 716 }
 717
 718 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
 719 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
 720 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
 721
 722 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
 723   getStreamer().emitPersonality(Personality);
 724 }
 725
 726 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
 727   getStreamer().emitPersonalityIndex(Index);
 728 }
 729
 730 void ARMTargetELFStreamer::emitHandlerData() {
 731   getStreamer().emitHandlerData();
 732 }
 733
 734 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
 735                                      int64_t Offset) {
 736   getStreamer().emitSetFP(FpReg, SpReg, Offset);
 737 }
 738
 739 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
 740   getStreamer().emitMovSP(Reg, Offset);
 741 }
 742
 743 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
 744   getStreamer().emitPad(Offset);
 745 }
 746
 747 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
 748                                        bool isVector) {
 749   getStreamer().emitRegSave(RegList, isVector);
 750 }
 751
 752 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
 753                                       const SmallVectorImpl<uint8_t> &Opcodes) {
 754   getStreamer().emitUnwindRaw(Offset, Opcodes);
 755 }
 756
 757 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
 758   assert(!Vendor.empty() && "Vendor cannot be empty.");
 759
 760   if (CurrentVendor == Vendor)
 761     return;
 762
 763   if (!CurrentVendor.empty())
 764     finishAttributeSection();
 765
 766   assert(Contents.empty() &&
 767          ".ARM.attributes should be flushed before changing vendor");
 768   CurrentVendor = Vendor;
 769
 770 }
 771
 772 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
 773   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
 774 }
 775
 776 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
 777                                              StringRef Value) {
 778   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
 779 }
 780
 781 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
 782                                                 unsigned IntValue,
 783                                                 StringRef StringValue) {
 784   setAttributeItems(Attribute, IntValue, StringValue,
 785                     /* OverwriteExisting= */ true);
 786 }
 787
 788 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
 789   Arch = Value;
 790 }
 791
 792 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
 793   EmittedArch = Value;
 794 }
 795
 796 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
 797   using namespace ARMBuildAttrs;
 798
 799   setAttributeItem(CPU_name,
 800                    ARM::getCPUAttr(Arch),
 801                    false);
 802
 803   if (EmittedArch == ARM::ArchKind::INVALID)
 804     setAttributeItem(CPU_arch,
 805                      ARM::getArchAttr(Arch),
 806                      false);
 807   else
 808     setAttributeItem(CPU_arch,
 809                      ARM::getArchAttr(EmittedArch),
 810                      false);
 811
 812   switch (Arch) {
 813   case ARM::ArchKind::ARMV2:
 814   case ARM::ArchKind::ARMV2A:
 815   case ARM::ArchKind::ARMV3:
 816   case ARM::ArchKind::ARMV3M:
 817   case ARM::ArchKind::ARMV4:
 818     setAttributeItem(ARM_ISA_use, Allowed, false);
 819     break;
 820
 821   case ARM::ArchKind::ARMV4T:
 822   case ARM::ArchKind::ARMV5T:
 823   case ARM::ArchKind::ARMV5TE:
 824   case ARM::ArchKind::ARMV6:
 825     setAttributeItem(ARM_ISA_use, Allowed, false);
 826     setAttributeItem(THUMB_ISA_use, Allowed, false);
 827     break;
 828
 829   case ARM::ArchKind::ARMV6T2:
 830     setAttributeItem(ARM_ISA_use, Allowed, false);
 831     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 832     break;
 833
 834   case ARM::ArchKind::ARMV6K:
 835   case ARM::ArchKind::ARMV6KZ:
 836     setAttributeItem(ARM_ISA_use, Allowed, false);
 837     setAttributeItem(THUMB_ISA_use, Allowed, false);
 838     setAttributeItem(Virtualization_use, AllowTZ, false);
 839     break;
 840
 841   case ARM::ArchKind::ARMV6M:
 842     setAttributeItem(THUMB_ISA_use, Allowed, false);
 843     break;
 844
 845   case ARM::ArchKind::ARMV7A:
 846     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 847     setAttributeItem(ARM_ISA_use, Allowed, false);
 848     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 849     break;
 850
 851   case ARM::ArchKind::ARMV7R:
 852     setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
 853     setAttributeItem(ARM_ISA_use, Allowed, false);
 854     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 855     break;
 856
 857   case ARM::ArchKind::ARMV7EM:
 858   case ARM::ArchKind::ARMV7M:
 859     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 860     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 861     break;
 862
 863   case ARM::ArchKind::ARMV8A:
 864   case ARM::ArchKind::ARMV8_1A:
 865   case ARM::ArchKind::ARMV8_2A:
 866   case ARM::ArchKind::ARMV8_3A:
 867   case ARM::ArchKind::ARMV8_4A:
 868   case ARM::ArchKind::ARMV8_5A:
 869     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
 870     setAttributeItem(ARM_ISA_use, Allowed, false);
 871     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
 872     setAttributeItem(MPextension_use, Allowed, false);
 873     setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
 874     break;
 875
 876   case ARM::ArchKind::ARMV8MBaseline:
 877   case ARM::ArchKind::ARMV8MMainline:
 878     setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
 879     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
 880     break;
 881
 882   case ARM::ArchKind::IWMMXT:
 883     setAttributeItem(ARM_ISA_use, Allowed, false);
 884     setAttributeItem(THUMB_ISA_use, Allowed, false);
 885     setAttributeItem(WMMX_arch, AllowWMMXv1, false);
 886     break;
 887
 888   case ARM::ArchKind::IWMMXT2:
 889     setAttributeItem(ARM_ISA_use, Allowed, false);
 890     setAttributeItem(THUMB_ISA_use, Allowed, false);
 891     setAttributeItem(WMMX_arch, AllowWMMXv2, false);
 892     break;
 893
 894   default:
 895     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
 896     break;
 897   }
 898 }
 899
 900 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
 901   FPU = Value;
 902 }
 903
 904 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
 905   switch (FPU) {
 906   case ARM::FK_VFP:
 907   case ARM::FK_VFPV2:
 908     setAttributeItem(ARMBuildAttrs::FP_arch,
 909                      ARMBuildAttrs::AllowFPv2,
 910                      /* OverwriteExisting= */ false);
 911     break;
 912
 913   case ARM::FK_VFPV3:
 914     setAttributeItem(ARMBuildAttrs::FP_arch,
 915                      ARMBuildAttrs::AllowFPv3A,
 916                      /* OverwriteExisting= */ false);
 917     break;
 918
 919   case ARM::FK_VFPV3_FP16:
 920     setAttributeItem(ARMBuildAttrs::FP_arch,
 921                      ARMBuildAttrs::AllowFPv3A,
 922                      /* OverwriteExisting= */ false);
 923     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
 924                      ARMBuildAttrs::AllowHPFP,
 925                      /* OverwriteExisting= */ false);
 926     break;
 927
 928   case ARM::FK_VFPV3_D16:
 929     setAttributeItem(ARMBuildAttrs::FP_arch,
 930                      ARMBuildAttrs::AllowFPv3B,
 931                      /* OverwriteExisting= */ false);
 932     break;
 933
 934   case ARM::FK_VFPV3_D16_FP16:
 935     setAttributeItem(ARMBuildAttrs::FP_arch,
 936                      ARMBuildAttrs::AllowFPv3B,
 937                      /* OverwriteExisting= */ false);
 938     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
 939                      ARMBuildAttrs::AllowHPFP,
 940                      /* OverwriteExisting= */ false);
 941     break;
 942
 943   case ARM::FK_VFPV3XD:
 944     setAttributeItem(ARMBuildAttrs::FP_arch,
 945                      ARMBuildAttrs::AllowFPv3B,
 946                      /* OverwriteExisting= */ false);
 947     break;
 948   case ARM::FK_VFPV3XD_FP16:
 949     setAttributeItem(ARMBuildAttrs::FP_arch,
 950                      ARMBuildAttrs::AllowFPv3B,
 951                      /* OverwriteExisting= */ false);
 952     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
 953                      ARMBuildAttrs::AllowHPFP,
 954                      /* OverwriteExisting= */ false);
 955     break;
 956
 957   case ARM::FK_VFPV4:
 958     setAttributeItem(ARMBuildAttrs::FP_arch,
 959                      ARMBuildAttrs::AllowFPv4A,
 960                      /* OverwriteExisting= */ false);
 961     break;
 962
 963   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
 964   // as _D16 here.
 965   case ARM::FK_FPV4_SP_D16:
 966   case ARM::FK_VFPV4_D16:
 967     setAttributeItem(ARMBuildAttrs::FP_arch,
 968                      ARMBuildAttrs::AllowFPv4B,
 969                      /* OverwriteExisting= */ false);
 970     break;
 971
 972   case ARM::FK_FP_ARMV8:
 973     setAttributeItem(ARMBuildAttrs::FP_arch,
 974                      ARMBuildAttrs::AllowFPARMv8A,
 975                      /* OverwriteExisting= */ false);
 976     break;
 977
 978   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
 979   // uses the FP_ARMV8_D16 build attribute.
 980   case ARM::FK_FPV5_SP_D16:
 981   case ARM::FK_FPV5_D16:
 982     setAttributeItem(ARMBuildAttrs::FP_arch,
 983                      ARMBuildAttrs::AllowFPARMv8B,
 984                      /* OverwriteExisting= */ false);
 985     break;
 986
 987   case ARM::FK_NEON:
 988     setAttributeItem(ARMBuildAttrs::FP_arch,
 989                      ARMBuildAttrs::AllowFPv3A,
 990                      /* OverwriteExisting= */ false);
 991     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
 992                      ARMBuildAttrs::AllowNeon,
 993                      /* OverwriteExisting= */ false);
 994     break;
 995
 996   case ARM::FK_NEON_FP16:
 997     setAttributeItem(ARMBuildAttrs::FP_arch,
 998                      ARMBuildAttrs::AllowFPv3A,
 999                      /* OverwriteExisting= */ false);
1000     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1001                      ARMBuildAttrs::AllowNeon,
1002                      /* OverwriteExisting= */ false);
1003     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
1004                      ARMBuildAttrs::AllowHPFP,
1005                      /* OverwriteExisting= */ false);
1006     break;
1007
1008   case ARM::FK_NEON_VFPV4:
1009     setAttributeItem(ARMBuildAttrs::FP_arch,
1010                      ARMBuildAttrs::AllowFPv4A,
1011                      /* OverwriteExisting= */ false);
1012     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1013                      ARMBuildAttrs::AllowNeon2,
1014                      /* OverwriteExisting= */ false);
1015     break;
1016
1017   case ARM::FK_NEON_FP_ARMV8:
1018   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1019     setAttributeItem(ARMBuildAttrs::FP_arch,
1020                      ARMBuildAttrs::AllowFPARMv8A,
1021                      /* OverwriteExisting= */ false);
1022     // 'Advanced_SIMD_arch' must be emitted not here, but within
1023     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1024     break;
1025
1026   case ARM::FK_SOFTVFP:
1027   case ARM::FK_NONE:
1028     break;
1029
1030   default:
1031     report_fatal_error("Unknown FPU: " + Twine(FPU));
1032     break;
1033   }
1034 }
1035
1036 size_t ARMTargetELFStreamer::calculateContentSize() const {
1037   size_t Result = 0;
1038   for (size_t i = 0; i < Contents.size(); ++i) {
1039     AttributeItem item = Contents[i];
1040     switch (item.Type) {
1041     case AttributeItem::HiddenAttribute:
1042       break;
1043     case AttributeItem::NumericAttribute:
1044       Result += getULEB128Size(item.Tag);
1045       Result += getULEB128Size(item.IntValue);
1046       break;
1047     case AttributeItem::TextAttribute:
1048       Result += getULEB128Size(item.Tag);
1049       Result += item.StringValue.size() + 1; // string + '\0'
1050       break;
1051     case AttributeItem::NumericAndTextAttributes:
1052       Result += getULEB128Size(item.Tag);
1053       Result += getULEB128Size(item.IntValue);
1054       Result += item.StringValue.size() + 1; // string + '\0';
1055       break;
1056     }
1057   }
1058   return Result;
1059 }
1060
1061 void ARMTargetELFStreamer::finishAttributeSection() {
1062   // <format-version>
1063   // [ <section-length> "vendor-name"
1064   // [ <file-tag> <size> <attribute>*
1065   //   | <section-tag> <size> <section-number>* 0 <attribute>*
1066   //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
1067   //   ]+
1068   // ]*
1069
1070   if (FPU != ARM::FK_INVALID)
1071     emitFPUDefaultAttributes();
1072
1073   if (Arch != ARM::ArchKind::INVALID)
1074     emitArchDefaultAttributes();
1075
1076   if (Contents.empty())
1077     return;
1078
1079   llvm::sort(Contents, AttributeItem::LessTag);
1080
1081   ARMELFStreamer &Streamer = getStreamer();
1082
1083   // Switch to .ARM.attributes section
1084   if (AttributeSection) {
1085     Streamer.SwitchSection(AttributeSection);
1086   } else {
1087     AttributeSection = Streamer.getContext().getELFSection(
1088         ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
1089     Streamer.SwitchSection(AttributeSection);
1090
1091     // Format version
1092     Streamer.EmitIntValue(0x41, 1);
1093   }
1094
1095   // Vendor size + Vendor name + '\0'
1096   const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
1097
1098   // Tag + Tag Size
1099   const size_t TagHeaderSize = 1 + 4;
1100
1101   const size_t ContentsSize = calculateContentSize();
1102
1103   Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
1104   Streamer.EmitBytes(CurrentVendor);
1105   Streamer.EmitIntValue(0, 1); // '\0'
1106
1107   Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
1108   Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
1109
1110   // Size should have been accounted for already, now
1111   // emit each field as its type (ULEB or String)
1112   for (size_t i = 0; i < Contents.size(); ++i) {
1113     AttributeItem item = Contents[i];
1114     Streamer.EmitULEB128IntValue(item.Tag);
1115     switch (item.Type) {
1116     default: llvm_unreachable("Invalid attribute type");
1117     case AttributeItem::NumericAttribute:
1118       Streamer.EmitULEB128IntValue(item.IntValue);
1119       break;
1120     case AttributeItem::TextAttribute:
1121       Streamer.EmitBytes(item.StringValue);
1122       Streamer.EmitIntValue(0, 1); // '\0'
1123       break;
1124     case AttributeItem::NumericAndTextAttributes:
1125       Streamer.EmitULEB128IntValue(item.IntValue);
1126       Streamer.EmitBytes(item.StringValue);
1127       Streamer.EmitIntValue(0, 1); // '\0'
1128       break;
1129     }
1130   }
1131
1132   Contents.clear();
1133   FPU = ARM::FK_INVALID;
1134 }
1135
1136 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1137   ARMELFStreamer &Streamer = getStreamer();
1138   if (!Streamer.IsThumb)
1139     return;
1140
1141   Streamer.getAssembler().registerSymbol(*Symbol);
1142   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1143   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1144     Streamer.EmitThumbFunc(Symbol);
1145 }
1146
1147 void
1148 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1149   getStreamer().EmitFixup(S, FK_Data_4);
1150 }
1151
1152 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1153   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1154     const MCSymbol &Sym = SRE->getSymbol();
1155     if (!Sym.isDefined()) {
1156       getStreamer().EmitAssignment(Symbol, Value);
1157       return;
1158     }
1159   }
1160
1161   getStreamer().EmitThumbFunc(Symbol);
1162   getStreamer().EmitAssignment(Symbol, Value);
1163 }
1164
1165 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1166   getStreamer().emitInst(Inst, Suffix);
1167 }
1168
1169 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1170
1171 void ARMELFStreamer::FinishImpl() {
1172   MCTargetStreamer &TS = *getTargetStreamer();
1173   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1174   ATS.finishAttributeSection();
1175
1176   MCELFStreamer::FinishImpl();
1177 }
1178
1179 void ARMELFStreamer::reset() {
1180   MCTargetStreamer &TS = *getTargetStreamer();
1181   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1182   ATS.reset();
1183   MappingSymbolCounter = 0;
1184   MCELFStreamer::reset();
1185   LastMappingSymbols.clear();
1186   LastEMSInfo.reset();
1187   // MCELFStreamer clear's the assembler's e_flags. However, for
1188   // arm we manually set the ABI version on streamer creation, so
1189   // do the same here
1190   getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1191 }
1192
1193 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1194                                               unsigned Type,
1195                                               unsigned Flags,
1196                                               SectionKind Kind,
1197                                               const MCSymbol &Fn) {
1198   const MCSectionELF &FnSection =
1199     static_cast<const MCSectionELF &>(Fn.getSection());
1200
1201   // Create the name for new section
1202   StringRef FnSecName(FnSection.getSectionName());
1203   SmallString<128> EHSecName(Prefix);
1204   if (FnSecName != ".text") {
1205     EHSecName += FnSecName;
1206   }
1207
1208   // Get .ARM.extab or .ARM.exidx section
1209   const MCSymbolELF *Group = FnSection.getGroup();
1210   if (Group)
1211     Flags |= ELF::SHF_GROUP;
1212   MCSectionELF *EHSection = getContext().getELFSection(
1213       EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
1214       static_cast<const MCSymbolELF *>(&Fn));
1215
1216   assert(EHSection && "Failed to get the required EH section");
1217
1218   // Switch to .ARM.extab or .ARM.exidx section
1219   SwitchSection(EHSection);
1220   EmitCodeAlignment(4);
1221 }
1222
1223 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1224   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1225                     SectionKind::getData(), FnStart);
1226 }
1227
1228 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1229   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1230                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1231                     SectionKind::getData(), FnStart);
1232 }
1233
1234 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1235   MCDataFragment *Frag = getOrCreateDataFragment();
1236   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1237                                               Kind));
1238 }
1239
1240 void ARMELFStreamer::EHReset() {
1241   ExTab = nullptr;
1242   FnStart = nullptr;
1243   Personality = nullptr;
1244   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1245   FPReg = ARM::SP;
1246   FPOffset = 0;
1247   SPOffset = 0;
1248   PendingOffset = 0;
1249   UsedFP = false;
1250   CantUnwind = false;
1251
1252   Opcodes.clear();
1253   UnwindOpAsm.Reset();
1254 }
1255
1256 void ARMELFStreamer::emitFnStart() {
1257   assert(FnStart == nullptr);
1258   FnStart = getContext().createTempSymbol();
1259   EmitLabel(FnStart);
1260 }
1261
1262 void ARMELFStreamer::emitFnEnd() {
1263   assert(FnStart && ".fnstart must precedes .fnend");
1264
1265   // Emit unwind opcodes if there is no .handlerdata directive
1266   if (!ExTab && !CantUnwind)
1267     FlushUnwindOpcodes(true);
1268
1269   // Emit the exception index table entry
1270   SwitchToExIdxSection(*FnStart);
1271
1272   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1273     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1274
1275   const MCSymbolRefExpr *FnStartRef =
1276     MCSymbolRefExpr::create(FnStart,
1277                             MCSymbolRefExpr::VK_ARM_PREL31,
1278                             getContext());
1279
1280   EmitValue(FnStartRef, 4);
1281
1282   if (CantUnwind) {
1283     EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1284   } else if (ExTab) {
1285     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1286     const MCSymbolRefExpr *ExTabEntryRef =
1287       MCSymbolRefExpr::create(ExTab,
1288                               MCSymbolRefExpr::VK_ARM_PREL31,
1289                               getContext());
1290     EmitValue(ExTabEntryRef, 4);
1291   } else {
1292     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1293     // the second word of exception index table entry.  The size of the unwind
1294     // opcodes should always be 4 bytes.
1295     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1296            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1297     assert(Opcodes.size() == 4u &&
1298            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1299     uint64_t Intval = Opcodes[0] |
1300                       Opcodes[1] << 8 |
1301                       Opcodes[2] << 16 |
1302                       Opcodes[3] << 24;
1303     EmitIntValue(Intval, Opcodes.size());
1304   }
1305
1306   // Switch to the section containing FnStart
1307   SwitchSection(&FnStart->getSection());
1308
1309   // Clean exception handling frame information
1310   EHReset();
1311 }
1312
1313 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1314
1315 // Add the R_ARM_NONE fixup at the same position
1316 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1317   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1318
1319   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1320       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1321
1322   visitUsedExpr(*PersonalityRef);
1323   MCDataFragment *DF = getOrCreateDataFragment();
1324   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1325                                             PersonalityRef,
1326                                             MCFixup::getKindForSize(4, false)));
1327 }
1328
1329 void ARMELFStreamer::FlushPendingOffset() {
1330   if (PendingOffset != 0) {
1331     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1332     PendingOffset = 0;
1333   }
1334 }
1335
1336 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1337   // Emit the unwind opcode to restore $sp.
1338   if (UsedFP) {
1339     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1340     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1341     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1342     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1343   } else {
1344     FlushPendingOffset();
1345   }
1346
1347   // Finalize the unwind opcode sequence
1348   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1349
1350   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1351   // section.  Thus, we don't have to create an entry in the .ARM.extab
1352   // section.
1353   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1354     return;
1355
1356   // Switch to .ARM.extab section.
1357   SwitchToExTabSection(*FnStart);
1358
1359   // Create .ARM.extab label for offset in .ARM.exidx
1360   assert(!ExTab);
1361   ExTab = getContext().createTempSymbol();
1362   EmitLabel(ExTab);
1363
1364   // Emit personality
1365   if (Personality) {
1366     const MCSymbolRefExpr *PersonalityRef =
1367       MCSymbolRefExpr::create(Personality,
1368                               MCSymbolRefExpr::VK_ARM_PREL31,
1369                               getContext());
1370
1371     EmitValue(PersonalityRef, 4);
1372   }
1373
1374   // Emit unwind opcodes
1375   assert((Opcodes.size() % 4) == 0 &&
1376          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1377   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1378     uint64_t Intval = Opcodes[I] |
1379                       Opcodes[I + 1] << 8 |
1380                       Opcodes[I + 2] << 16 |
1381                       Opcodes[I + 3] << 24;
1382     EmitIntValue(Intval, 4);
1383   }
1384
1385   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1386   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1387   // after the unwind opcodes.  The handler data consists of several 32-bit
1388   // words, and should be terminated by zero.
1389   //
1390   // In case that the .handlerdata directive is not specified by the
1391   // programmer, we should emit zero to terminate the handler data.
1392   if (NoHandlerData && !Personality)
1393     EmitIntValue(0, 4);
1394 }
1395
1396 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1397
1398 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1399   Personality = Per;
1400   UnwindOpAsm.setPersonality(Per);
1401 }
1402
1403 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1404   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1405   PersonalityIndex = Index;
1406 }
1407
1408 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1409                                int64_t Offset) {
1410   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1411          "the operand of .setfp directive should be either $sp or $fp");
1412
1413   UsedFP = true;
1414   FPReg = NewFPReg;
1415
1416   if (NewSPReg == ARM::SP)
1417     FPOffset = SPOffset + Offset;
1418   else
1419     FPOffset += Offset;
1420 }
1421
1422 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1423   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1424          "the operand of .movsp cannot be either sp or pc");
1425   assert(FPReg == ARM::SP && "current FP must be SP");
1426
1427   FlushPendingOffset();
1428
1429   FPReg = Reg;
1430   FPOffset = SPOffset + Offset;
1431
1432   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1433   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1434 }
1435
1436 void ARMELFStreamer::emitPad(int64_t Offset) {
1437   // Track the change of the $sp offset
1438   SPOffset -= Offset;
1439
1440   // To squash multiple .pad directives, we should delay the unwind opcode
1441   // until the .save, .vsave, .handlerdata, or .fnend directives.
1442   PendingOffset -= Offset;
1443 }
1444
1445 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1446                                  bool IsVector) {
1447   // Collect the registers in the register list
1448   unsigned Count = 0;
1449   uint32_t Mask = 0;
1450   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1451   for (size_t i = 0; i < RegList.size(); ++i) {
1452     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1453     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1454     unsigned Bit = (1u << Reg);
1455     if ((Mask & Bit) == 0) {
1456       Mask |= Bit;
1457       ++Count;
1458     }
1459   }
1460
1461   // Track the change the $sp offset: For the .save directive, the
1462   // corresponding push instruction will decrease the $sp by (4 * Count).
1463   // For the .vsave directive, the corresponding vpush instruction will
1464   // decrease $sp by (8 * Count).
1465   SPOffset -= Count * (IsVector ? 8 : 4);
1466
1467   // Emit the opcode
1468   FlushPendingOffset();
1469   if (IsVector)
1470     UnwindOpAsm.EmitVFPRegSave(Mask);
1471   else
1472     UnwindOpAsm.EmitRegSave(Mask);
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                                              bool isVerboseAsm) {
1488   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1489 }
1490
1491 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1492   return new ARMTargetStreamer(S);
1493 }
1494
1495 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1496                                                 const MCSubtargetInfo &STI) {
1497   const Triple &TT = STI.getTargetTriple();
1498   if (TT.isOSBinFormatELF())
1499     return new ARMTargetELFStreamer(S);
1500   return new ARMTargetStreamer(S);
1501 }
1502
1503 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1504                                     std::unique_ptr<MCAsmBackend> TAB,
1505                                     std::unique_ptr<MCObjectWriter> OW,
1506                                     std::unique_ptr<MCCodeEmitter> Emitter,
1507                                     bool RelaxAll, bool IsThumb) {
1508   ARMELFStreamer *S = new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1509                                          std::move(Emitter), IsThumb);
1510   // FIXME: This should eventually end up somewhere else where more
1511   // intelligent flag decisions can be made. For now we are just maintaining
1512   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1513   S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1514
1515   if (RelaxAll)
1516     S->getAssembler().setRelaxAll(true);
1517   return S;
1518 }
1519
1520 } // end namespace llvm