llvm/lib/DebugInfo/DWARF/DWARFDie.cpp

   1 //===- DWARFDie.cpp -------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
  10 #include "llvm/ADT/None.h"
  11 #include "llvm/ADT/Optional.h"
  12 #include "llvm/ADT/SmallSet.h"
  13 #include "llvm/ADT/StringRef.h"
  14 #include "llvm/BinaryFormat/Dwarf.h"
  15 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
  16 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  17 #include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
  18 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
  19 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
  20 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
  21 #include "llvm/Object/ObjectFile.h"
  22 #include "llvm/Support/DataExtractor.h"
  23 #include "llvm/Support/Format.h"
  24 #include "llvm/Support/FormatAdapters.h"
  25 #include "llvm/Support/FormatVariadic.h"
  26 #include "llvm/Support/MathExtras.h"
  27 #include "llvm/Support/WithColor.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include <algorithm>
  30 #include <cassert>
  31 #include <cinttypes>
  32 #include <cstdint>
  33 #include <string>
  34 #include <utility>
  35
  36 using namespace llvm;
  37 using namespace dwarf;
  38 using namespace object;
  39
  40 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
  41   OS << " (";
  42   do {
  43     uint64_t Shift = countTrailingZeros(Val);
  44     assert(Shift < 64 && "undefined behavior");
  45     uint64_t Bit = 1ULL << Shift;
  46     auto PropName = ApplePropertyString(Bit);
  47     if (!PropName.empty())
  48       OS << PropName;
  49     else
  50       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
  51     if (!(Val ^= Bit))
  52       break;
  53     OS << ", ";
  54   } while (true);
  55   OS << ")";
  56 }
  57
  58 static void dumpRanges(const DWARFObject &Obj, raw_ostream &OS,
  59                        const DWARFAddressRangesVector &Ranges,
  60                        unsigned AddressSize, unsigned Indent,
  61                        const DIDumpOptions &DumpOpts) {
  62   if (!DumpOpts.ShowAddresses)
  63     return;
  64
  65   for (const DWARFAddressRange &R : Ranges) {
  66     OS << '\n';
  67     OS.indent(Indent);
  68     R.dump(OS, AddressSize, DumpOpts, &Obj);
  69   }
  70 }
  71
  72 static void dumpLocationList(raw_ostream &OS, const DWARFFormValue &FormValue,
  73                              DWARFUnit *U, unsigned Indent,
  74                              DIDumpOptions DumpOpts) {
  75   assert(FormValue.isFormClass(DWARFFormValue::FC_SectionOffset) &&
  76          "bad FORM for location list");
  77   DWARFContext &Ctx = U->getContext();
  78   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
  79   uint64_t Offset = *FormValue.getAsSectionOffset();
  80
  81   if (FormValue.getForm() == DW_FORM_loclistx) {
  82     FormValue.dump(OS, DumpOpts);
  83
  84     if (auto LoclistOffset = U->getLoclistOffset(Offset))
  85       Offset = *LoclistOffset;
  86     else
  87       return;
  88   }
  89   U->getLocationTable().dumpLocationList(&Offset, OS, U->getBaseAddress(), MRI,
  90                                          Ctx.getDWARFObj(), U, DumpOpts,
  91                                          Indent);
  92   return;
  93 }
  94
  95 static void dumpLocationExpr(raw_ostream &OS, const DWARFFormValue &FormValue,
  96                              DWARFUnit *U, unsigned Indent,
  97                              DIDumpOptions DumpOpts) {
  98   assert((FormValue.isFormClass(DWARFFormValue::FC_Block) ||
  99           FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) &&
 100          "bad FORM for location expression");
 101   DWARFContext &Ctx = U->getContext();
 102   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
 103   ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
 104   DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
 105                      Ctx.isLittleEndian(), 0);
 106   DWARFExpression(Data, U->getAddressByteSize(), U->getFormParams().Format)
 107       .print(OS, DumpOpts, MRI, U);
 108   return;
 109 }
 110
 111 /// Dump the name encoded in the type tag.
 112 static void dumpTypeTagName(raw_ostream &OS, dwarf::Tag T) {
 113   StringRef TagStr = TagString(T);
 114   if (!TagStr.startswith("DW_TAG_") || !TagStr.endswith("_type"))
 115     return;
 116   OS << TagStr.substr(7, TagStr.size() - 12) << " ";
 117 }
 118
 119 static void dumpArrayType(raw_ostream &OS, const DWARFDie &D) {
 120   for (const DWARFDie &C : D.children())
 121     if (C.getTag() == DW_TAG_subrange_type) {
 122       Optional<uint64_t> LB;
 123       Optional<uint64_t> Count;
 124       Optional<uint64_t> UB;
 125       Optional<unsigned> DefaultLB;
 126       if (Optional<DWARFFormValue> L = C.find(DW_AT_lower_bound))
 127         LB = L->getAsUnsignedConstant();
 128       if (Optional<DWARFFormValue> CountV = C.find(DW_AT_count))
 129         Count = CountV->getAsUnsignedConstant();
 130       if (Optional<DWARFFormValue> UpperV = C.find(DW_AT_upper_bound))
 131         UB = UpperV->getAsUnsignedConstant();
 132       if (Optional<DWARFFormValue> LV =
 133               D.getDwarfUnit()->getUnitDIE().find(DW_AT_language))
 134         if (Optional<uint64_t> LC = LV->getAsUnsignedConstant())
 135           if ((DefaultLB =
 136                    LanguageLowerBound(static_cast<dwarf::SourceLanguage>(*LC))))
 137             if (LB && *LB == *DefaultLB)
 138               LB = None;
 139       if (!LB && !Count && !UB)
 140         OS << "[]";
 141       else if (!LB && (Count || UB) && DefaultLB)
 142         OS << '[' << (Count ? *Count : *UB - *DefaultLB + 1) << ']';
 143       else {
 144         OS << "[[";
 145         if (LB)
 146           OS << *LB;
 147         else
 148           OS << '?';
 149         OS << ", ";
 150         if (Count)
 151           if (LB)
 152             OS << *LB + *Count;
 153           else
 154             OS << "? + " << *Count;
 155         else if (UB)
 156           OS << *UB + 1;
 157         else
 158           OS << '?';
 159         OS << ")]";
 160       }
 161     }
 162 }
 163
 164 /// Recursively dump the DIE type name when applicable.
 165 static void dumpTypeName(raw_ostream &OS, const DWARFDie &D) {
 166   if (!D.isValid())
 167     return;
 168
 169   if (const char *Name = D.getName(DINameKind::LinkageName)) {
 170     OS << Name;
 171     return;
 172   }
 173
 174   // FIXME: We should have pretty printers per language. Currently we print
 175   // everything as if it was C++ and fall back to the TAG type name.
 176   const dwarf::Tag T = D.getTag();
 177   switch (T) {
 178   case DW_TAG_array_type:
 179   case DW_TAG_pointer_type:
 180   case DW_TAG_ptr_to_member_type:
 181   case DW_TAG_reference_type:
 182   case DW_TAG_rvalue_reference_type:
 183   case DW_TAG_subroutine_type:
 184     break;
 185   default:
 186     dumpTypeTagName(OS, T);
 187   }
 188
 189   // Follow the DW_AT_type if possible.
 190   DWARFDie TypeDie = D.getAttributeValueAsReferencedDie(DW_AT_type);
 191   dumpTypeName(OS, TypeDie);
 192
 193   switch (T) {
 194   case DW_TAG_subroutine_type: {
 195     if (!TypeDie)
 196       OS << "void";
 197     OS << '(';
 198     bool First = true;
 199     for (const DWARFDie &C : D.children()) {
 200       if (C.getTag() == DW_TAG_formal_parameter) {
 201         if (!First)
 202           OS << ", ";
 203         First = false;
 204         dumpTypeName(OS, C.getAttributeValueAsReferencedDie(DW_AT_type));
 205       }
 206     }
 207     OS << ')';
 208     break;
 209   }
 210   case DW_TAG_array_type: {
 211     dumpArrayType(OS, D);
 212     break;
 213   }
 214   case DW_TAG_pointer_type:
 215     OS << '*';
 216     break;
 217   case DW_TAG_ptr_to_member_type:
 218     if (DWARFDie Cont =
 219             D.getAttributeValueAsReferencedDie(DW_AT_containing_type)) {
 220       dumpTypeName(OS << ' ', Cont);
 221       OS << "::";
 222     }
 223     OS << '*';
 224     break;
 225   case DW_TAG_reference_type:
 226     OS << '&';
 227     break;
 228   case DW_TAG_rvalue_reference_type:
 229     OS << "&&";
 230     break;
 231   default:
 232     break;
 233   }
 234 }
 235
 236 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
 237                           const DWARFAttribute &AttrValue, unsigned Indent,
 238                           DIDumpOptions DumpOpts) {
 239   if (!Die.isValid())
 240     return;
 241   const char BaseIndent[] = "            ";
 242   OS << BaseIndent;
 243   OS.indent(Indent + 2);
 244   dwarf::Attribute Attr = AttrValue.Attr;
 245   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
 246
 247   dwarf::Form Form = AttrValue.Value.getForm();
 248   if (DumpOpts.Verbose || DumpOpts.ShowForm)
 249     OS << formatv(" [{0}]", Form);
 250
 251   DWARFUnit *U = Die.getDwarfUnit();
 252   const DWARFFormValue &FormValue = AttrValue.Value;
 253
 254   OS << "\t(";
 255
 256   StringRef Name;
 257   std::string File;
 258   auto Color = HighlightColor::Enumerator;
 259   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
 260     Color = HighlightColor::String;
 261     if (const auto *LT = U->getContext().getLineTableForUnit(U))
 262       if (LT->getFileNameByIndex(
 263               FormValue.getAsUnsignedConstant().getValue(),
 264               U->getCompilationDir(),
 265               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
 266         File = '"' + File + '"';
 267         Name = File;
 268       }
 269   } else if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
 270     Name = AttributeValueString(Attr, *Val);
 271
 272   if (!Name.empty())
 273     WithColor(OS, Color) << Name;
 274   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
 275     OS << *FormValue.getAsUnsignedConstant();
 276   else if (Attr == DW_AT_low_pc &&
 277            (FormValue.getAsAddress() ==
 278             dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
 279     if (DumpOpts.Verbose) {
 280       FormValue.dump(OS, DumpOpts);
 281       OS << " (";
 282     }
 283     OS << "dead code";
 284     if (DumpOpts.Verbose)
 285       OS << ')';
 286   } else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
 287              FormValue.getAsUnsignedConstant()) {
 288     if (DumpOpts.ShowAddresses) {
 289       // Print the actual address rather than the offset.
 290       uint64_t LowPC, HighPC, Index;
 291       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
 292         DWARFFormValue::dumpAddress(OS, U->getAddressByteSize(), HighPC);
 293       else
 294         FormValue.dump(OS, DumpOpts);
 295     }
 296   } else if (DWARFAttribute::mayHaveLocationList(Attr) &&
 297              FormValue.isFormClass(DWARFFormValue::FC_SectionOffset))
 298     dumpLocationList(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
 299                      DumpOpts);
 300   else if (FormValue.isFormClass(DWARFFormValue::FC_Exprloc) ||
 301            (DWARFAttribute::mayHaveLocationExpr(Attr) &&
 302             FormValue.isFormClass(DWARFFormValue::FC_Block)))
 303     dumpLocationExpr(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
 304                      DumpOpts);
 305   else
 306     FormValue.dump(OS, DumpOpts);
 307
 308   std::string Space = DumpOpts.ShowAddresses ? " " : "";
 309
 310   // We have dumped the attribute raw value. For some attributes
 311   // having both the raw value and the pretty-printed value is
 312   // interesting. These attributes are handled below.
 313   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
 314     if (const char *Name =
 315             Die.getAttributeValueAsReferencedDie(FormValue).getName(
 316                 DINameKind::LinkageName))
 317       OS << Space << "\"" << Name << '\"';
 318   } else if (Attr == DW_AT_type) {
 319     OS << Space << "\"";
 320     dumpTypeName(OS, Die.getAttributeValueAsReferencedDie(FormValue));
 321     OS << '"';
 322   } else if (Attr == DW_AT_APPLE_property_attribute) {
 323     if (Optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
 324       dumpApplePropertyAttribute(OS, *OptVal);
 325   } else if (Attr == DW_AT_ranges) {
 326     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
 327     // For DW_FORM_rnglistx we need to dump the offset separately, since
 328     // we have only dumped the index so far.
 329     if (FormValue.getForm() == DW_FORM_rnglistx)
 330       if (auto RangeListOffset =
 331               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
 332         DWARFFormValue FV = DWARFFormValue::createFromUValue(
 333             dwarf::DW_FORM_sec_offset, *RangeListOffset);
 334         FV.dump(OS, DumpOpts);
 335       }
 336     if (auto RangesOrError = Die.getAddressRanges())
 337       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
 338                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
 339     else
 340       DumpOpts.RecoverableErrorHandler(createStringError(
 341           errc::invalid_argument, "decoding address ranges: %s",
 342           toString(RangesOrError.takeError()).c_str()));
 343   }
 344
 345   OS << ")\n";
 346 }
 347
 348 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
 349
 350 bool DWARFDie::isSubroutineDIE() const {
 351   auto Tag = getTag();
 352   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
 353 }
 354
 355 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
 356   if (!isValid())
 357     return None;
 358   auto AbbrevDecl = getAbbreviationDeclarationPtr();
 359   if (AbbrevDecl)
 360     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
 361   return None;
 362 }
 363
 364 Optional<DWARFFormValue>
 365 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
 366   if (!isValid())
 367     return None;
 368   auto AbbrevDecl = getAbbreviationDeclarationPtr();
 369   if (AbbrevDecl) {
 370     for (auto Attr : Attrs) {
 371       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
 372         return Value;
 373     }
 374   }
 375   return None;
 376 }
 377
 378 Optional<DWARFFormValue>
 379 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
 380   SmallVector<DWARFDie, 3> Worklist;
 381   Worklist.push_back(*this);
 382
 383   // Keep track if DIEs already seen to prevent infinite recursion.
 384   // Empirically we rarely see a depth of more than 3 when dealing with valid
 385   // DWARF. This corresponds to following the DW_AT_abstract_origin and
 386   // DW_AT_specification just once.
 387   SmallSet<DWARFDie, 3> Seen;
 388   Seen.insert(*this);
 389
 390   while (!Worklist.empty()) {
 391     DWARFDie Die = Worklist.pop_back_val();
 392
 393     if (!Die.isValid())
 394       continue;
 395
 396     if (auto Value = Die.find(Attrs))
 397       return Value;
 398
 399     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
 400       if (Seen.insert(D).second)
 401         Worklist.push_back(D);
 402
 403     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
 404       if (Seen.insert(D).second)
 405         Worklist.push_back(D);
 406   }
 407
 408   return None;
 409 }
 410
 411 DWARFDie
 412 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
 413   if (Optional<DWARFFormValue> F = find(Attr))
 414     return getAttributeValueAsReferencedDie(*F);
 415   return DWARFDie();
 416 }
 417
 418 DWARFDie
 419 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
 420   if (auto SpecRef = V.getAsRelativeReference()) {
 421     if (SpecRef->Unit)
 422       return SpecRef->Unit->getDIEForOffset(SpecRef->Unit->getOffset() + SpecRef->Offset);
 423     if (auto SpecUnit = U->getUnitVector().getUnitForOffset(SpecRef->Offset))
 424       return SpecUnit->getDIEForOffset(SpecRef->Offset);
 425   }
 426   return DWARFDie();
 427 }
 428
 429 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
 430   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
 431 }
 432
 433 Optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
 434   return toSectionOffset(find(DW_AT_loclists_base));
 435 }
 436
 437 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
 438   uint64_t Tombstone = dwarf::computeTombstoneAddress(U->getAddressByteSize());
 439   if (LowPC == Tombstone)
 440     return None;
 441   if (auto FormValue = find(DW_AT_high_pc)) {
 442     if (auto Address = FormValue->getAsAddress()) {
 443       // High PC is an address.
 444       return Address;
 445     }
 446     if (auto Offset = FormValue->getAsUnsignedConstant()) {
 447       // High PC is an offset from LowPC.
 448       return LowPC + *Offset;
 449     }
 450   }
 451   return None;
 452 }
 453
 454 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
 455                                uint64_t &SectionIndex) const {
 456   auto F = find(DW_AT_low_pc);
 457   auto LowPcAddr = toSectionedAddress(F);
 458   if (!LowPcAddr)
 459     return false;
 460   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
 461     LowPC = LowPcAddr->Address;
 462     HighPC = *HighPcAddr;
 463     SectionIndex = LowPcAddr->SectionIndex;
 464     return true;
 465   }
 466   return false;
 467 }
 468
 469 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
 470   if (isNULL())
 471     return DWARFAddressRangesVector();
 472   // Single range specified by low/high PC.
 473   uint64_t LowPC, HighPC, Index;
 474   if (getLowAndHighPC(LowPC, HighPC, Index))
 475     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
 476
 477   Optional<DWARFFormValue> Value = find(DW_AT_ranges);
 478   if (Value) {
 479     if (Value->getForm() == DW_FORM_rnglistx)
 480       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
 481     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
 482   }
 483   return DWARFAddressRangesVector();
 484 }
 485
 486 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
 487   auto RangesOrError = getAddressRanges();
 488   if (!RangesOrError) {
 489     llvm::consumeError(RangesOrError.takeError());
 490     return false;
 491   }
 492
 493   for (const auto &R : RangesOrError.get())
 494     if (R.LowPC <= Address && Address < R.HighPC)
 495       return true;
 496   return false;
 497 }
 498
 499 Expected<DWARFLocationExpressionsVector>
 500 DWARFDie::getLocations(dwarf::Attribute Attr) const {
 501   Optional<DWARFFormValue> Location = find(Attr);
 502   if (!Location)
 503     return createStringError(inconvertibleErrorCode(), "No %s",
 504                              dwarf::AttributeString(Attr).data());
 505
 506   if (Optional<uint64_t> Off = Location->getAsSectionOffset()) {
 507     uint64_t Offset = *Off;
 508
 509     if (Location->getForm() == DW_FORM_loclistx) {
 510       if (auto LoclistOffset = U->getLoclistOffset(Offset))
 511         Offset = *LoclistOffset;
 512       else
 513         return createStringError(inconvertibleErrorCode(),
 514                                  "Loclist table not found");
 515     }
 516     return U->findLoclistFromOffset(Offset);
 517   }
 518
 519   if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
 520     return DWARFLocationExpressionsVector{
 521         DWARFLocationExpression{None, to_vector<4>(*Expr)}};
 522   }
 523
 524   return createStringError(
 525       inconvertibleErrorCode(), "Unsupported %s encoding: %s",
 526       dwarf::AttributeString(Attr).data(),
 527       dwarf::FormEncodingString(Location->getForm()).data());
 528 }
 529
 530 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
 531   if (!isSubroutineDIE())
 532     return nullptr;
 533   return getName(Kind);
 534 }
 535
 536 const char *DWARFDie::getName(DINameKind Kind) const {
 537   if (!isValid() || Kind == DINameKind::None)
 538     return nullptr;
 539   // Try to get mangled name only if it was asked for.
 540   if (Kind == DINameKind::LinkageName) {
 541     if (auto Name = getLinkageName())
 542       return Name;
 543   }
 544   return getShortName();
 545 }
 546
 547 const char *DWARFDie::getShortName() const {
 548   if (!isValid())
 549     return nullptr;
 550
 551   return dwarf::toString(findRecursively(dwarf::DW_AT_name), nullptr);
 552 }
 553
 554 const char *DWARFDie::getLinkageName() const {
 555   if (!isValid())
 556     return nullptr;
 557
 558   return dwarf::toString(findRecursively({dwarf::DW_AT_MIPS_linkage_name,
 559                                           dwarf::DW_AT_linkage_name}),
 560                          nullptr);
 561 }
 562
 563 uint64_t DWARFDie::getDeclLine() const {
 564   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
 565 }
 566
 567 std::string
 568 DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
 569   auto D = getAttributeValueAsReferencedDie(DW_AT_abstract_origin);
 570   if (!D)
 571     D = *this;
 572   std::string FileName;
 573   if (auto DeclFile = toUnsigned(D.find(DW_AT_decl_file))) {
 574     if (const auto *LineTable =
 575             getDwarfUnit()->getContext().getLineTableForUnit(
 576                 D.getDwarfUnit()->getLinkedUnit()))
 577       LineTable->getFileNameByIndex(
 578           *DeclFile, D.getDwarfUnit()->getCompilationDir(), Kind, FileName);
 579   }
 580   return FileName;
 581 }
 582
 583 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
 584                               uint32_t &CallColumn,
 585                               uint32_t &CallDiscriminator) const {
 586   CallFile = toUnsigned(find(DW_AT_call_file), 0);
 587   CallLine = toUnsigned(find(DW_AT_call_line), 0);
 588   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
 589   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
 590 }
 591
 592 /// Helper to dump a DIE with all of its parents, but no siblings.
 593 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
 594                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
 595   if (!Die)
 596     return Indent;
 597   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
 598     return Indent;
 599   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
 600   Die.dump(OS, Indent, DumpOpts);
 601   return Indent + 2;
 602 }
 603
 604 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
 605                     DIDumpOptions DumpOpts) const {
 606   if (!isValid())
 607     return;
 608   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
 609   const uint64_t Offset = getOffset();
 610   uint64_t offset = Offset;
 611   if (DumpOpts.ShowParents) {
 612     DIDumpOptions ParentDumpOpts = DumpOpts;
 613     ParentDumpOpts.ShowParents = false;
 614     ParentDumpOpts.ShowChildren = false;
 615     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
 616   }
 617
 618   if (debug_info_data.isValidOffset(offset)) {
 619     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
 620     if (DumpOpts.ShowAddresses)
 621       WithColor(OS, HighlightColor::Address).get()
 622           << format("\n0x%8.8" PRIx64 ": ", Offset);
 623
 624     if (abbrCode) {
 625       auto AbbrevDecl = getAbbreviationDeclarationPtr();
 626       if (AbbrevDecl) {
 627         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
 628             << formatv("{0}", getTag());
 629         if (DumpOpts.Verbose)
 630           OS << format(" [%u] %c", abbrCode,
 631                        AbbrevDecl->hasChildren() ? '*' : ' ');
 632         OS << '\n';
 633
 634         // Dump all data in the DIE for the attributes.
 635         for (const DWARFAttribute &AttrValue : attributes())
 636           dumpAttribute(OS, *this, AttrValue, Indent, DumpOpts);
 637
 638         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0) {
 639           DWARFDie Child = getFirstChild();
 640           DumpOpts.ChildRecurseDepth--;
 641           DIDumpOptions ChildDumpOpts = DumpOpts;
 642           ChildDumpOpts.ShowParents = false;
 643           while (Child) {
 644             Child.dump(OS, Indent + 2, ChildDumpOpts);
 645             Child = Child.getSibling();
 646           }
 647         }
 648       } else {
 649         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
 650            << abbrCode << '\n';
 651       }
 652     } else {
 653       OS.indent(Indent) << "NULL\n";
 654     }
 655   }
 656 }
 657
 658 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
 659
 660 DWARFDie DWARFDie::getParent() const {
 661   if (isValid())
 662     return U->getParent(Die);
 663   return DWARFDie();
 664 }
 665
 666 DWARFDie DWARFDie::getSibling() const {
 667   if (isValid())
 668     return U->getSibling(Die);
 669   return DWARFDie();
 670 }
 671
 672 DWARFDie DWARFDie::getPreviousSibling() const {
 673   if (isValid())
 674     return U->getPreviousSibling(Die);
 675   return DWARFDie();
 676 }
 677
 678 DWARFDie DWARFDie::getFirstChild() const {
 679   if (isValid())
 680     return U->getFirstChild(Die);
 681   return DWARFDie();
 682 }
 683
 684 DWARFDie DWARFDie::getLastChild() const {
 685   if (isValid())
 686     return U->getLastChild(Die);
 687   return DWARFDie();
 688 }
 689
 690 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
 691   return make_range(attribute_iterator(*this, false),
 692                     attribute_iterator(*this, true));
 693 }
 694
 695 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
 696     : Die(D), Index(0) {
 697   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
 698   assert(AbbrDecl && "Must have abbreviation declaration");
 699   if (End) {
 700     // This is the end iterator so we set the index to the attribute count.
 701     Index = AbbrDecl->getNumAttributes();
 702   } else {
 703     // This is the begin iterator so we extract the value for this->Index.
 704     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
 705     updateForIndex(*AbbrDecl, 0);
 706   }
 707 }
 708
 709 void DWARFDie::attribute_iterator::updateForIndex(
 710     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
 711   Index = I;
 712   // AbbrDecl must be valid before calling this function.
 713   auto NumAttrs = AbbrDecl.getNumAttributes();
 714   if (Index < NumAttrs) {
 715     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
 716     // Add the previous byte size of any previous attribute value.
 717     AttrValue.Offset += AttrValue.ByteSize;
 718     uint64_t ParseOffset = AttrValue.Offset;
 719     if (AbbrDecl.getAttrIsImplicitConstByIndex(Index))
 720       AttrValue.Value = DWARFFormValue::createFromSValue(
 721           AbbrDecl.getFormByIndex(Index),
 722           AbbrDecl.getAttrImplicitConstValueByIndex(Index));
 723     else {
 724       auto U = Die.getDwarfUnit();
 725       assert(U && "Die must have valid DWARF unit");
 726       AttrValue.Value = DWARFFormValue::createFromUnit(
 727           AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
 728     }
 729     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
 730   } else {
 731     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
 732     AttrValue = {};
 733   }
 734 }
 735
 736 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
 737   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
 738     updateForIndex(*AbbrDecl, Index + 1);
 739   return *this;
 740 }
 741
 742 bool DWARFAttribute::mayHaveLocationList(dwarf::Attribute Attr) {
 743   switch(Attr) {
 744   case DW_AT_location:
 745   case DW_AT_string_length:
 746   case DW_AT_return_addr:
 747   case DW_AT_data_member_location:
 748   case DW_AT_frame_base:
 749   case DW_AT_static_link:
 750   case DW_AT_segment:
 751   case DW_AT_use_location:
 752   case DW_AT_vtable_elem_location:
 753     return true;
 754   default:
 755     return false;
 756   }
 757 }
 758
 759 bool DWARFAttribute::mayHaveLocationExpr(dwarf::Attribute Attr) {
 760   switch (Attr) {
 761   // From the DWARF v5 specification.
 762   case DW_AT_location:
 763   case DW_AT_byte_size:
 764   case DW_AT_bit_offset:
 765   case DW_AT_bit_size:
 766   case DW_AT_string_length:
 767   case DW_AT_lower_bound:
 768   case DW_AT_return_addr:
 769   case DW_AT_bit_stride:
 770   case DW_AT_upper_bound:
 771   case DW_AT_count:
 772   case DW_AT_data_member_location:
 773   case DW_AT_frame_base:
 774   case DW_AT_segment:
 775   case DW_AT_static_link:
 776   case DW_AT_use_location:
 777   case DW_AT_vtable_elem_location:
 778   case DW_AT_allocated:
 779   case DW_AT_associated:
 780   case DW_AT_data_location:
 781   case DW_AT_byte_stride:
 782   case DW_AT_rank:
 783   case DW_AT_call_value:
 784   case DW_AT_call_origin:
 785   case DW_AT_call_target:
 786   case DW_AT_call_target_clobbered:
 787   case DW_AT_call_data_location:
 788   case DW_AT_call_data_value:
 789   // Extensions.
 790   case DW_AT_GNU_call_site_value:
 791   case DW_AT_GNU_call_site_target:
 792     return true;
 793   default:
 794     return false;
 795   }
 796 }