lib/MC/MCObjectStreamer.cpp

   1 //===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/MC/MCObjectStreamer.h"
  11 #include "llvm/ADT/STLExtras.h"
  12 #include "llvm/MC/MCAsmBackend.h"
  13 #include "llvm/MC/MCAssembler.h"
  14 #include "llvm/MC/MCCodeEmitter.h"
  15 #include "llvm/MC/MCCodeView.h"
  16 #include "llvm/MC/MCContext.h"
  17 #include "llvm/MC/MCDwarf.h"
  18 #include "llvm/MC/MCExpr.h"
  19 #include "llvm/MC/MCObjectWriter.h"
  20 #include "llvm/MC/MCSection.h"
  21 #include "llvm/MC/MCSymbol.h"
  22 #include "llvm/Support/ErrorHandling.h"
  23 #include "llvm/Support/SourceMgr.h"
  24 using namespace llvm;
  25
  26 MCObjectStreamer::MCObjectStreamer(MCContext &Context,
  27                                    std::unique_ptr<MCAsmBackend> TAB,
  28                                    std::unique_ptr<MCObjectWriter> OW,
  29                                    std::unique_ptr<MCCodeEmitter> Emitter)
  30     : MCStreamer(Context),
  31       Assembler(llvm::make_unique<MCAssembler>(
  32           Context, std::move(TAB), std::move(Emitter), std::move(OW))),
  33       EmitEHFrame(true), EmitDebugFrame(false) {}
  34
  35 MCObjectStreamer::~MCObjectStreamer() {}
  36
  37 // AssemblerPtr is used for evaluation of expressions and causes
  38 // difference between asm and object outputs. Return nullptr to in
  39 // inline asm mode to limit divergence to assembly inputs.
  40 MCAssembler *MCObjectStreamer::getAssemblerPtr() {
  41   if (getUseAssemblerInfoForParsing())
  42     return Assembler.get();
  43   return nullptr;
  44 }
  45
  46 void MCObjectStreamer::flushPendingLabels(MCFragment *F, uint64_t FOffset) {
  47   if (PendingLabels.empty())
  48     return;
  49   if (!F) {
  50     F = new MCDataFragment();
  51     MCSection *CurSection = getCurrentSectionOnly();
  52     CurSection->getFragmentList().insert(CurInsertionPoint, F);
  53     F->setParent(CurSection);
  54   }
  55   for (MCSymbol *Sym : PendingLabels) {
  56     Sym->setFragment(F);
  57     Sym->setOffset(FOffset);
  58   }
  59   PendingLabels.clear();
  60 }
  61
  62 // As a compile-time optimization, avoid allocating and evaluating an MCExpr
  63 // tree for (Hi - Lo) when Hi and Lo are offsets into the same fragment.
  64 static Optional<uint64_t> absoluteSymbolDiff(const MCSymbol *Hi,
  65                                              const MCSymbol *Lo) {
  66   assert(Hi && Lo);
  67   if (!Hi->getFragment() || Hi->getFragment() != Lo->getFragment() ||
  68       Hi->isVariable() || Lo->isVariable())
  69     return None;
  70
  71   return Hi->getOffset() - Lo->getOffset();
  72 }
  73
  74 void MCObjectStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi,
  75                                               const MCSymbol *Lo,
  76                                               unsigned Size) {
  77   if (Optional<uint64_t> Diff = absoluteSymbolDiff(Hi, Lo)) {
  78     EmitIntValue(*Diff, Size);
  79     return;
  80   }
  81   MCStreamer::emitAbsoluteSymbolDiff(Hi, Lo, Size);
  82 }
  83
  84 void MCObjectStreamer::emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
  85                                                        const MCSymbol *Lo) {
  86   if (Optional<uint64_t> Diff = absoluteSymbolDiff(Hi, Lo)) {
  87     EmitULEB128IntValue(*Diff);
  88     return;
  89   }
  90   MCStreamer::emitAbsoluteSymbolDiffAsULEB128(Hi, Lo);
  91 }
  92
  93 void MCObjectStreamer::reset() {
  94   if (Assembler)
  95     Assembler->reset();
  96   CurInsertionPoint = MCSection::iterator();
  97   EmitEHFrame = true;
  98   EmitDebugFrame = false;
  99   PendingLabels.clear();
 100   MCStreamer::reset();
 101 }
 102
 103 void MCObjectStreamer::EmitFrames(MCAsmBackend *MAB) {
 104   if (!getNumFrameInfos())
 105     return;
 106
 107   if (EmitEHFrame)
 108     MCDwarfFrameEmitter::Emit(*this, MAB, true);
 109
 110   if (EmitDebugFrame)
 111     MCDwarfFrameEmitter::Emit(*this, MAB, false);
 112 }
 113
 114 MCFragment *MCObjectStreamer::getCurrentFragment() const {
 115   assert(getCurrentSectionOnly() && "No current section!");
 116
 117   if (CurInsertionPoint != getCurrentSectionOnly()->getFragmentList().begin())
 118     return &*std::prev(CurInsertionPoint);
 119
 120   return nullptr;
 121 }
 122
 123 static bool CanReuseDataFragment(const MCDataFragment &F,
 124                                  const MCAssembler &Assembler,
 125                                  const MCSubtargetInfo *STI) {
 126   if (!F.hasInstructions())
 127     return true;
 128   // When bundling is enabled, we don't want to add data to a fragment that
 129   // already has instructions (see MCELFStreamer::EmitInstToData for details)
 130   if (Assembler.isBundlingEnabled())
 131     return Assembler.getRelaxAll();
 132   // If the subtarget is changed mid fragment we start a new fragment to record
 133   // the new STI.
 134   return !STI || F.getSubtargetInfo() == STI;
 135 }
 136
 137 MCDataFragment *
 138 MCObjectStreamer::getOrCreateDataFragment(const MCSubtargetInfo *STI) {
 139   MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
 140   if (!F || !CanReuseDataFragment(*F, *Assembler, STI)) {
 141     F = new MCDataFragment();
 142     insert(F);
 143   }
 144   return F;
 145 }
 146
 147 MCPaddingFragment *MCObjectStreamer::getOrCreatePaddingFragment() {
 148   MCPaddingFragment *F =
 149       dyn_cast_or_null<MCPaddingFragment>(getCurrentFragment());
 150   if (!F) {
 151     F = new MCPaddingFragment();
 152     insert(F);
 153   }
 154   return F;
 155 }
 156
 157 void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
 158   Assembler->registerSymbol(Sym);
 159 }
 160
 161 void MCObjectStreamer::EmitCFISections(bool EH, bool Debug) {
 162   MCStreamer::EmitCFISections(EH, Debug);
 163   EmitEHFrame = EH;
 164   EmitDebugFrame = Debug;
 165 }
 166
 167 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
 168                                      SMLoc Loc) {
 169   MCStreamer::EmitValueImpl(Value, Size, Loc);
 170   MCDataFragment *DF = getOrCreateDataFragment();
 171   flushPendingLabels(DF, DF->getContents().size());
 172
 173   MCCVLineEntry::Make(this);
 174   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
 175
 176   // Avoid fixups when possible.
 177   int64_t AbsValue;
 178   if (Value->evaluateAsAbsolute(AbsValue, getAssemblerPtr())) {
 179     if (!isUIntN(8 * Size, AbsValue) && !isIntN(8 * Size, AbsValue)) {
 180       getContext().reportError(
 181           Loc, "value evaluated as " + Twine(AbsValue) + " is out of range.");
 182       return;
 183     }
 184     EmitIntValue(AbsValue, Size);
 185     return;
 186   }
 187   DF->getFixups().push_back(
 188       MCFixup::create(DF->getContents().size(), Value,
 189                       MCFixup::getKindForSize(Size, false), Loc));
 190   DF->getContents().resize(DF->getContents().size() + Size, 0);
 191 }
 192
 193 MCSymbol *MCObjectStreamer::EmitCFILabel() {
 194   MCSymbol *Label = getContext().createTempSymbol("cfi", true);
 195   EmitLabel(Label);
 196   return Label;
 197 }
 198
 199 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
 200   // We need to create a local symbol to avoid relocations.
 201   Frame.Begin = getContext().createTempSymbol();
 202   EmitLabel(Frame.Begin);
 203 }
 204
 205 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
 206   Frame.End = getContext().createTempSymbol();
 207   EmitLabel(Frame.End);
 208 }
 209
 210 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol, SMLoc Loc) {
 211   MCStreamer::EmitLabel(Symbol, Loc);
 212
 213   getAssembler().registerSymbol(*Symbol);
 214
 215   // If there is a current fragment, mark the symbol as pointing into it.
 216   // Otherwise queue the label and set its fragment pointer when we emit the
 217   // next fragment.
 218   auto *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
 219   if (F && !(getAssembler().isBundlingEnabled() &&
 220              getAssembler().getRelaxAll())) {
 221     Symbol->setFragment(F);
 222     Symbol->setOffset(F->getContents().size());
 223   } else {
 224     PendingLabels.push_back(Symbol);
 225   }
 226 }
 227
 228 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol, SMLoc Loc, MCFragment *F) {
 229   MCStreamer::EmitLabel(Symbol, Loc);
 230   getAssembler().registerSymbol(*Symbol);
 231   auto *DF = dyn_cast_or_null<MCDataFragment>(F);
 232   if (DF)
 233     Symbol->setFragment(F);
 234   else
 235     PendingLabels.push_back(Symbol);
 236 }
 237
 238 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
 239   int64_t IntValue;
 240   if (Value->evaluateAsAbsolute(IntValue, getAssemblerPtr())) {
 241     EmitULEB128IntValue(IntValue);
 242     return;
 243   }
 244   insert(new MCLEBFragment(*Value, false));
 245 }
 246
 247 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
 248   int64_t IntValue;
 249   if (Value->evaluateAsAbsolute(IntValue, getAssemblerPtr())) {
 250     EmitSLEB128IntValue(IntValue);
 251     return;
 252   }
 253   insert(new MCLEBFragment(*Value, true));
 254 }
 255
 256 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
 257                                          const MCSymbol *Symbol) {
 258   report_fatal_error("This file format doesn't support weak aliases.");
 259 }
 260
 261 void MCObjectStreamer::ChangeSection(MCSection *Section,
 262                                      const MCExpr *Subsection) {
 263   changeSectionImpl(Section, Subsection);
 264 }
 265
 266 bool MCObjectStreamer::changeSectionImpl(MCSection *Section,
 267                                          const MCExpr *Subsection) {
 268   assert(Section && "Cannot switch to a null section!");
 269   flushPendingLabels(nullptr);
 270   getContext().clearCVLocSeen();
 271   getContext().clearDwarfLocSeen();
 272
 273   bool Created = getAssembler().registerSection(*Section);
 274
 275   int64_t IntSubsection = 0;
 276   if (Subsection &&
 277       !Subsection->evaluateAsAbsolute(IntSubsection, getAssemblerPtr()))
 278     report_fatal_error("Cannot evaluate subsection number");
 279   if (IntSubsection < 0 || IntSubsection > 8192)
 280     report_fatal_error("Subsection number out of range");
 281   CurInsertionPoint =
 282       Section->getSubsectionInsertionPoint(unsigned(IntSubsection));
 283   return Created;
 284 }
 285
 286 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
 287   getAssembler().registerSymbol(*Symbol);
 288   MCStreamer::EmitAssignment(Symbol, Value);
 289 }
 290
 291 bool MCObjectStreamer::mayHaveInstructions(MCSection &Sec) const {
 292   return Sec.hasInstructions();
 293 }
 294
 295 void MCObjectStreamer::EmitInstruction(const MCInst &Inst,
 296                                        const MCSubtargetInfo &STI, bool) {
 297   getAssembler().getBackend().handleCodePaddingInstructionBegin(Inst);
 298   EmitInstructionImpl(Inst, STI);
 299   getAssembler().getBackend().handleCodePaddingInstructionEnd(Inst);
 300 }
 301
 302 void MCObjectStreamer::EmitInstructionImpl(const MCInst &Inst,
 303                                            const MCSubtargetInfo &STI) {
 304   MCStreamer::EmitInstruction(Inst, STI);
 305
 306   MCSection *Sec = getCurrentSectionOnly();
 307   Sec->setHasInstructions(true);
 308
 309   // Now that a machine instruction has been assembled into this section, make
 310   // a line entry for any .loc directive that has been seen.
 311   MCCVLineEntry::Make(this);
 312   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
 313
 314   // If this instruction doesn't need relaxation, just emit it as data.
 315   MCAssembler &Assembler = getAssembler();
 316   if (!Assembler.getBackend().mayNeedRelaxation(Inst, STI)) {
 317     EmitInstToData(Inst, STI);
 318     return;
 319   }
 320
 321   // Otherwise, relax and emit it as data if either:
 322   // - The RelaxAll flag was passed
 323   // - Bundling is enabled and this instruction is inside a bundle-locked
 324   //   group. We want to emit all such instructions into the same data
 325   //   fragment.
 326   if (Assembler.getRelaxAll() ||
 327       (Assembler.isBundlingEnabled() && Sec->isBundleLocked())) {
 328     MCInst Relaxed;
 329     getAssembler().getBackend().relaxInstruction(Inst, STI, Relaxed);
 330     while (getAssembler().getBackend().mayNeedRelaxation(Relaxed, STI))
 331       getAssembler().getBackend().relaxInstruction(Relaxed, STI, Relaxed);
 332     EmitInstToData(Relaxed, STI);
 333     return;
 334   }
 335
 336   // Otherwise emit to a separate fragment.
 337   EmitInstToFragment(Inst, STI);
 338 }
 339
 340 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst,
 341                                           const MCSubtargetInfo &STI) {
 342   if (getAssembler().getRelaxAll() && getAssembler().isBundlingEnabled())
 343     llvm_unreachable("All instructions should have already been relaxed");
 344
 345   // Always create a new, separate fragment here, because its size can change
 346   // during relaxation.
 347   MCRelaxableFragment *IF = new MCRelaxableFragment(Inst, STI);
 348   insert(IF);
 349
 350   SmallString<128> Code;
 351   raw_svector_ostream VecOS(Code);
 352   getAssembler().getEmitter().encodeInstruction(Inst, VecOS, IF->getFixups(),
 353                                                 STI);
 354   IF->getContents().append(Code.begin(), Code.end());
 355 }
 356
 357 #ifndef NDEBUG
 358 static const char *const BundlingNotImplementedMsg =
 359   "Aligned bundling is not implemented for this object format";
 360 #endif
 361
 362 void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
 363   llvm_unreachable(BundlingNotImplementedMsg);
 364 }
 365
 366 void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
 367   llvm_unreachable(BundlingNotImplementedMsg);
 368 }
 369
 370 void MCObjectStreamer::EmitBundleUnlock() {
 371   llvm_unreachable(BundlingNotImplementedMsg);
 372 }
 373
 374 void MCObjectStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
 375                                              unsigned Column, unsigned Flags,
 376                                              unsigned Isa,
 377                                              unsigned Discriminator,
 378                                              StringRef FileName) {
 379   // In case we see two .loc directives in a row, make sure the
 380   // first one gets a line entry.
 381   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
 382
 383   this->MCStreamer::EmitDwarfLocDirective(FileNo, Line, Column, Flags,
 384                                           Isa, Discriminator, FileName);
 385 }
 386
 387 static const MCExpr *buildSymbolDiff(MCObjectStreamer &OS, const MCSymbol *A,
 388                                      const MCSymbol *B) {
 389   MCContext &Context = OS.getContext();
 390   MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
 391   const MCExpr *ARef = MCSymbolRefExpr::create(A, Variant, Context);
 392   const MCExpr *BRef = MCSymbolRefExpr::create(B, Variant, Context);
 393   const MCExpr *AddrDelta =
 394       MCBinaryExpr::create(MCBinaryExpr::Sub, ARef, BRef, Context);
 395   return AddrDelta;
 396 }
 397
 398 static void emitDwarfSetLineAddr(MCObjectStreamer &OS,
 399                                  MCDwarfLineTableParams Params,
 400                                  int64_t LineDelta, const MCSymbol *Label,
 401                                  int PointerSize) {
 402   // emit the sequence to set the address
 403   OS.EmitIntValue(dwarf::DW_LNS_extended_op, 1);
 404   OS.EmitULEB128IntValue(PointerSize + 1);
 405   OS.EmitIntValue(dwarf::DW_LNE_set_address, 1);
 406   OS.EmitSymbolValue(Label, PointerSize);
 407
 408   // emit the sequence for the LineDelta (from 1) and a zero address delta.
 409   MCDwarfLineAddr::Emit(&OS, Params, LineDelta, 0);
 410 }
 411
 412 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
 413                                                 const MCSymbol *LastLabel,
 414                                                 const MCSymbol *Label,
 415                                                 unsigned PointerSize) {
 416   if (!LastLabel) {
 417     emitDwarfSetLineAddr(*this, Assembler->getDWARFLinetableParams(), LineDelta,
 418                          Label, PointerSize);
 419     return;
 420   }
 421   const MCExpr *AddrDelta = buildSymbolDiff(*this, Label, LastLabel);
 422   int64_t Res;
 423   if (AddrDelta->evaluateAsAbsolute(Res, getAssemblerPtr())) {
 424     MCDwarfLineAddr::Emit(this, Assembler->getDWARFLinetableParams(), LineDelta,
 425                           Res);
 426     return;
 427   }
 428   insert(new MCDwarfLineAddrFragment(LineDelta, *AddrDelta));
 429 }
 430
 431 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
 432                                                  const MCSymbol *Label) {
 433   const MCExpr *AddrDelta = buildSymbolDiff(*this, Label, LastLabel);
 434   int64_t Res;
 435   if (AddrDelta->evaluateAsAbsolute(Res, getAssemblerPtr())) {
 436     MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
 437     return;
 438   }
 439   insert(new MCDwarfCallFrameFragment(*AddrDelta));
 440 }
 441
 442 void MCObjectStreamer::EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
 443                                           unsigned Line, unsigned Column,
 444                                           bool PrologueEnd, bool IsStmt,
 445                                           StringRef FileName, SMLoc Loc) {
 446   // In case we see two .cv_loc directives in a row, make sure the
 447   // first one gets a line entry.
 448   MCCVLineEntry::Make(this);
 449
 450   this->MCStreamer::EmitCVLocDirective(FunctionId, FileNo, Line, Column,
 451                                        PrologueEnd, IsStmt, FileName, Loc);
 452 }
 453
 454 void MCObjectStreamer::EmitCVLinetableDirective(unsigned FunctionId,
 455                                                 const MCSymbol *Begin,
 456                                                 const MCSymbol *End) {
 457   getContext().getCVContext().emitLineTableForFunction(*this, FunctionId, Begin,
 458                                                        End);
 459   this->MCStreamer::EmitCVLinetableDirective(FunctionId, Begin, End);
 460 }
 461
 462 void MCObjectStreamer::EmitCVInlineLinetableDirective(
 463     unsigned PrimaryFunctionId, unsigned SourceFileId, unsigned SourceLineNum,
 464     const MCSymbol *FnStartSym, const MCSymbol *FnEndSym) {
 465   getContext().getCVContext().emitInlineLineTableForFunction(
 466       *this, PrimaryFunctionId, SourceFileId, SourceLineNum, FnStartSym,
 467       FnEndSym);
 468   this->MCStreamer::EmitCVInlineLinetableDirective(
 469       PrimaryFunctionId, SourceFileId, SourceLineNum, FnStartSym, FnEndSym);
 470 }
 471
 472 void MCObjectStreamer::EmitCVDefRangeDirective(
 473     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
 474     StringRef FixedSizePortion) {
 475   getContext().getCVContext().emitDefRange(*this, Ranges, FixedSizePortion);
 476   this->MCStreamer::EmitCVDefRangeDirective(Ranges, FixedSizePortion);
 477 }
 478
 479 void MCObjectStreamer::EmitCVStringTableDirective() {
 480   getContext().getCVContext().emitStringTable(*this);
 481 }
 482 void MCObjectStreamer::EmitCVFileChecksumsDirective() {
 483   getContext().getCVContext().emitFileChecksums(*this);
 484 }
 485
 486 void MCObjectStreamer::EmitCVFileChecksumOffsetDirective(unsigned FileNo) {
 487   getContext().getCVContext().emitFileChecksumOffset(*this, FileNo);
 488 }
 489
 490 void MCObjectStreamer::EmitBytes(StringRef Data) {
 491   MCCVLineEntry::Make(this);
 492   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
 493   MCDataFragment *DF = getOrCreateDataFragment();
 494   flushPendingLabels(DF, DF->getContents().size());
 495   DF->getContents().append(Data.begin(), Data.end());
 496 }
 497
 498 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
 499                                             int64_t Value,
 500                                             unsigned ValueSize,
 501                                             unsigned MaxBytesToEmit) {
 502   if (MaxBytesToEmit == 0)
 503     MaxBytesToEmit = ByteAlignment;
 504   insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
 505
 506   // Update the maximum alignment on the current section if necessary.
 507   MCSection *CurSec = getCurrentSectionOnly();
 508   if (ByteAlignment > CurSec->getAlignment())
 509     CurSec->setAlignment(ByteAlignment);
 510 }
 511
 512 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
 513                                          unsigned MaxBytesToEmit) {
 514   EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
 515   cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
 516 }
 517
 518 void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,
 519                                          unsigned char Value,
 520                                          SMLoc Loc) {
 521   insert(new MCOrgFragment(*Offset, Value, Loc));
 522 }
 523
 524 void MCObjectStreamer::EmitCodePaddingBasicBlockStart(
 525     const MCCodePaddingContext &Context) {
 526   getAssembler().getBackend().handleCodePaddingBasicBlockStart(this, Context);
 527 }
 528
 529 void MCObjectStreamer::EmitCodePaddingBasicBlockEnd(
 530     const MCCodePaddingContext &Context) {
 531   getAssembler().getBackend().handleCodePaddingBasicBlockEnd(Context);
 532 }
 533
 534 // Associate DTPRel32 fixup with data and resize data area
 535 void MCObjectStreamer::EmitDTPRel32Value(const MCExpr *Value) {
 536   MCDataFragment *DF = getOrCreateDataFragment();
 537   flushPendingLabels(DF, DF->getContents().size());
 538
 539   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
 540                                             Value, FK_DTPRel_4));
 541   DF->getContents().resize(DF->getContents().size() + 4, 0);
 542 }
 543
 544 // Associate DTPRel64 fixup with data and resize data area
 545 void MCObjectStreamer::EmitDTPRel64Value(const MCExpr *Value) {
 546   MCDataFragment *DF = getOrCreateDataFragment();
 547   flushPendingLabels(DF, DF->getContents().size());
 548
 549   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
 550                                             Value, FK_DTPRel_8));
 551   DF->getContents().resize(DF->getContents().size() + 8, 0);
 552 }
 553
 554 // Associate TPRel32 fixup with data and resize data area
 555 void MCObjectStreamer::EmitTPRel32Value(const MCExpr *Value) {
 556   MCDataFragment *DF = getOrCreateDataFragment();
 557   flushPendingLabels(DF, DF->getContents().size());
 558
 559   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
 560                                             Value, FK_TPRel_4));
 561   DF->getContents().resize(DF->getContents().size() + 4, 0);
 562 }
 563
 564 // Associate TPRel64 fixup with data and resize data area
 565 void MCObjectStreamer::EmitTPRel64Value(const MCExpr *Value) {
 566   MCDataFragment *DF = getOrCreateDataFragment();
 567   flushPendingLabels(DF, DF->getContents().size());
 568
 569   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
 570                                             Value, FK_TPRel_8));
 571   DF->getContents().resize(DF->getContents().size() + 8, 0);
 572 }
 573
 574 // Associate GPRel32 fixup with data and resize data area
 575 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
 576   MCDataFragment *DF = getOrCreateDataFragment();
 577   flushPendingLabels(DF, DF->getContents().size());
 578
 579   DF->getFixups().push_back(
 580       MCFixup::create(DF->getContents().size(), Value, FK_GPRel_4));
 581   DF->getContents().resize(DF->getContents().size() + 4, 0);
 582 }
 583
 584 // Associate GPRel64 fixup with data and resize data area
 585 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
 586   MCDataFragment *DF = getOrCreateDataFragment();
 587   flushPendingLabels(DF, DF->getContents().size());
 588
 589   DF->getFixups().push_back(
 590       MCFixup::create(DF->getContents().size(), Value, FK_GPRel_4));
 591   DF->getContents().resize(DF->getContents().size() + 8, 0);
 592 }
 593
 594 bool MCObjectStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
 595                                           const MCExpr *Expr, SMLoc Loc,
 596                                           const MCSubtargetInfo &STI) {
 597   int64_t OffsetValue;
 598   if (!Offset.evaluateAsAbsolute(OffsetValue))
 599     llvm_unreachable("Offset is not absolute");
 600
 601   if (OffsetValue < 0)
 602     llvm_unreachable("Offset is negative");
 603
 604   MCDataFragment *DF = getOrCreateDataFragment(&STI);
 605   flushPendingLabels(DF, DF->getContents().size());
 606
 607   Optional<MCFixupKind> MaybeKind = Assembler->getBackend().getFixupKind(Name);
 608   if (!MaybeKind.hasValue())
 609     return true;
 610
 611   MCFixupKind Kind = *MaybeKind;
 612
 613   if (Expr == nullptr)
 614     Expr =
 615         MCSymbolRefExpr::create(getContext().createTempSymbol(), getContext());
 616   DF->getFixups().push_back(MCFixup::create(OffsetValue, Expr, Kind, Loc));
 617   return false;
 618 }
 619
 620 void MCObjectStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,
 621                                 SMLoc Loc) {
 622   MCDataFragment *DF = getOrCreateDataFragment();
 623   flushPendingLabels(DF, DF->getContents().size());
 624
 625   assert(getCurrentSectionOnly() && "need a section");
 626   insert(new MCFillFragment(FillValue, 1, NumBytes, Loc));
 627 }
 628
 629 void MCObjectStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
 630                                 int64_t Expr, SMLoc Loc) {
 631   int64_t IntNumValues;
 632   // Do additional checking now if we can resolve the value.
 633   if (NumValues.evaluateAsAbsolute(IntNumValues, getAssemblerPtr())) {
 634     if (IntNumValues < 0) {
 635       getContext().getSourceManager()->PrintMessage(
 636           Loc, SourceMgr::DK_Warning,
 637           "'.fill' directive with negative repeat count has no effect");
 638       return;
 639     }
 640     // Emit now if we can for better errors.
 641     int64_t NonZeroSize = Size > 4 ? 4 : Size;
 642     Expr &= ~0ULL >> (64 - NonZeroSize * 8);
 643     for (uint64_t i = 0, e = IntNumValues; i != e; ++i) {
 644       EmitIntValue(Expr, NonZeroSize);
 645       if (NonZeroSize < Size)
 646         EmitIntValue(0, Size - NonZeroSize);
 647     }
 648     return;
 649   }
 650
 651   // Otherwise emit as fragment.
 652   MCDataFragment *DF = getOrCreateDataFragment();
 653   flushPendingLabels(DF, DF->getContents().size());
 654
 655   assert(getCurrentSectionOnly() && "need a section");
 656   insert(new MCFillFragment(Expr, Size, NumValues, Loc));
 657 }
 658
 659 void MCObjectStreamer::EmitFileDirective(StringRef Filename) {
 660   getAssembler().addFileName(Filename);
 661 }
 662
 663 void MCObjectStreamer::FinishImpl() {
 664   // If we are generating dwarf for assembly source files dump out the sections.
 665   if (getContext().getGenDwarfForAssembly())
 666     MCGenDwarfInfo::Emit(this);
 667
 668   // Dump out the dwarf file & directory tables and line tables.
 669   MCDwarfLineTable::Emit(this, getAssembler().getDWARFLinetableParams());
 670
 671   flushPendingLabels(nullptr);
 672   getAssembler().Finish();
 673 }