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/FormatVariadic.h"
  25 #include "llvm/Support/MathExtras.h"
  26 #include "llvm/Support/WithColor.h"
  27 #include "llvm/Support/raw_ostream.h"
  28 #include <algorithm>
  29 #include <cassert>
  30 #include <cinttypes>
  31 #include <cstdint>
  32 #include <string>
  33 #include <utility>
  34
  35 using namespace llvm;
  36 using namespace dwarf;
  37 using namespace object;
  38
  39 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
  40   OS << " (";
  41   do {
  42     uint64_t Shift = countTrailingZeros(Val);
  43     assert(Shift < 64 && "undefined behavior");
  44     uint64_t Bit = 1ULL << Shift;
  45     auto PropName = ApplePropertyString(Bit);
  46     if (!PropName.empty())
  47       OS << PropName;
  48     else
  49       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
  50     if (!(Val ^= Bit))
  51       break;
  52     OS << ", ";
  53   } while (true);
  54   OS << ")";
  55 }
  56
  57 static void dumpRanges(const DWARFObject &Obj, raw_ostream &OS,
  58                        const DWARFAddressRangesVector &Ranges,
  59                        unsigned AddressSize, unsigned Indent,
  60                        const DIDumpOptions &DumpOpts) {
  61   if (!DumpOpts.ShowAddresses)
  62     return;
  63
  64   ArrayRef<SectionName> SectionNames;
  65   if (DumpOpts.Verbose)
  66     SectionNames = Obj.getSectionNames();
  67
  68   for (const DWARFAddressRange &R : Ranges) {
  69     OS << '\n';
  70     OS.indent(Indent);
  71     R.dump(OS, AddressSize);
  72
  73     DWARFFormValue::dumpAddressSection(Obj, OS, DumpOpts, R.SectionIndex);
  74   }
  75 }
  76
  77 static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
  78                          DWARFUnit *U, unsigned Indent,
  79                          DIDumpOptions DumpOpts) {
  80   DWARFContext &Ctx = U->getContext();
  81   const DWARFObject &Obj = Ctx.getDWARFObj();
  82   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
  83   if (FormValue.isFormClass(DWARFFormValue::FC_Block) ||
  84       FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) {
  85     ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
  86     DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
  87                        Ctx.isLittleEndian(), 0);
  88     DWARFExpression(Data, U->getVersion(), U->getAddressByteSize())
  89         .print(OS, MRI, U);
  90     return;
  91   }
  92
  93   FormValue.dump(OS, DumpOpts);
  94   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
  95     uint64_t Offset = *FormValue.getAsSectionOffset();
  96     if (!U->isDWOUnit() && !U->getLocSection()->Data.empty()) {
  97       DWARFDebugLoc DebugLoc;
  98       DWARFDataExtractor Data(Obj, *U->getLocSection(), Ctx.isLittleEndian(),
  99                               Obj.getAddressSize());
 100       auto LL = DebugLoc.parseOneLocationList(Data, &Offset);
 101       if (LL) {
 102         uint64_t BaseAddr = 0;
 103         if (Optional<object::SectionedAddress> BA = U->getBaseAddress())
 104           BaseAddr = BA->Address;
 105         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, U,
 106                  BaseAddr, Indent);
 107       } else
 108         OS << "error extracting location list.";
 109       return;
 110     }
 111
 112     bool UseLocLists = !U->isDWOUnit();
 113     StringRef LoclistsSectionData =
 114         UseLocLists ? Obj.getLoclistsSection().Data : U->getLocSectionData();
 115
 116     if (!LoclistsSectionData.empty()) {
 117       DataExtractor Data(LoclistsSectionData, Ctx.isLittleEndian(),
 118                          Obj.getAddressSize());
 119
 120       // Old-style location list were used in DWARF v4 (.debug_loc.dwo section).
 121       // Modern locations list (.debug_loclists) are used starting from v5.
 122       // Ideally we should take the version from the .debug_loclists section
 123       // header, but using CU's version for simplicity.
 124       auto LL = DWARFDebugLoclists::parseOneLocationList(
 125           Data, &Offset, UseLocLists ? U->getVersion() : 4);
 126
 127       uint64_t BaseAddr = 0;
 128       if (Optional<object::SectionedAddress> BA = U->getBaseAddress())
 129         BaseAddr = BA->Address;
 130
 131       if (LL)
 132         LL->dump(OS, BaseAddr, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI,
 133                  U, Indent);
 134       else
 135         OS << "error extracting location list.";
 136     }
 137   }
 138 }
 139
 140 /// Dump the name encoded in the type tag.
 141 static void dumpTypeTagName(raw_ostream &OS, dwarf::Tag T) {
 142   StringRef TagStr = TagString(T);
 143   if (!TagStr.startswith("DW_TAG_") || !TagStr.endswith("_type"))
 144     return;
 145   OS << TagStr.substr(7, TagStr.size() - 12) << " ";
 146 }
 147
 148 static void dumpArrayType(raw_ostream &OS, const DWARFDie &D) {
 149   Optional<uint64_t> Bound;
 150   for (const DWARFDie &C : D.children())
 151     if (C.getTag() == DW_TAG_subrange_type) {
 152       Optional<uint64_t> LB;
 153       Optional<uint64_t> Count;
 154       Optional<uint64_t> UB;
 155       Optional<unsigned> DefaultLB;
 156       if (Optional<DWARFFormValue> L = C.find(DW_AT_lower_bound))
 157         LB = L->getAsUnsignedConstant();
 158       if (Optional<DWARFFormValue> CountV = C.find(DW_AT_count))
 159         Count = CountV->getAsUnsignedConstant();
 160       if (Optional<DWARFFormValue> UpperV = C.find(DW_AT_upper_bound))
 161         UB = UpperV->getAsUnsignedConstant();
 162       if (Optional<DWARFFormValue> LV =
 163               D.getDwarfUnit()->getUnitDIE().find(DW_AT_language))
 164         if (Optional<uint64_t> LC = LV->getAsUnsignedConstant())
 165           if ((DefaultLB =
 166                    LanguageLowerBound(static_cast<dwarf::SourceLanguage>(*LC))))
 167             if (LB && *LB == *DefaultLB)
 168               LB = None;
 169       if (!LB && !Count && !UB)
 170         OS << "[]";
 171       else if (!LB && (Count || UB) && DefaultLB)
 172         OS << '[' << (Count ? *Count : *UB - *DefaultLB + 1) << ']';
 173       else {
 174         OS << "[[";
 175         if (LB)
 176           OS << *LB;
 177         else
 178           OS << '?';
 179         OS << ", ";
 180         if (Count)
 181           if (LB)
 182             OS << *LB + *Count;
 183           else
 184             OS << "? + " << *Count;
 185         else if (UB)
 186           OS << *UB + 1;
 187         else
 188           OS << '?';
 189         OS << ")]";
 190       }
 191     }
 192 }
 193
 194 /// Recursively dump the DIE type name when applicable.
 195 static void dumpTypeName(raw_ostream &OS, const DWARFDie &D) {
 196   if (!D.isValid())
 197     return;
 198
 199   if (const char *Name = D.getName(DINameKind::LinkageName)) {
 200     OS << Name;
 201     return;
 202   }
 203
 204   // FIXME: We should have pretty printers per language. Currently we print
 205   // everything as if it was C++ and fall back to the TAG type name.
 206   const dwarf::Tag T = D.getTag();
 207   switch (T) {
 208   case DW_TAG_array_type:
 209   case DW_TAG_pointer_type:
 210   case DW_TAG_ptr_to_member_type:
 211   case DW_TAG_reference_type:
 212   case DW_TAG_rvalue_reference_type:
 213   case DW_TAG_subroutine_type:
 214     break;
 215   default:
 216     dumpTypeTagName(OS, T);
 217   }
 218
 219   // Follow the DW_AT_type if possible.
 220   DWARFDie TypeDie = D.getAttributeValueAsReferencedDie(DW_AT_type);
 221   dumpTypeName(OS, TypeDie);
 222
 223   switch (T) {
 224   case DW_TAG_subroutine_type: {
 225     if (!TypeDie)
 226       OS << "void";
 227     OS << '(';
 228     bool First = true;
 229     for (const DWARFDie &C : D.children()) {
 230       if (C.getTag() == DW_TAG_formal_parameter) {
 231         if (!First)
 232           OS << ", ";
 233         First = false;
 234         dumpTypeName(OS, C.getAttributeValueAsReferencedDie(DW_AT_type));
 235       }
 236     }
 237     OS << ')';
 238     break;
 239   }
 240   case DW_TAG_array_type: {
 241     dumpArrayType(OS, D);
 242     break;
 243   }
 244   case DW_TAG_pointer_type:
 245     OS << '*';
 246     break;
 247   case DW_TAG_ptr_to_member_type:
 248     if (DWARFDie Cont =
 249             D.getAttributeValueAsReferencedDie(DW_AT_containing_type)) {
 250       dumpTypeName(OS << ' ', Cont);
 251       OS << "::";
 252     }
 253     OS << '*';
 254     break;
 255   case DW_TAG_reference_type:
 256     OS << '&';
 257     break;
 258   case DW_TAG_rvalue_reference_type:
 259     OS << "&&";
 260     break;
 261   default:
 262     break;
 263   }
 264 }
 265
 266 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
 267                           uint64_t *OffsetPtr, dwarf::Attribute Attr,
 268                           dwarf::Form Form, unsigned Indent,
 269                           DIDumpOptions DumpOpts) {
 270   if (!Die.isValid())
 271     return;
 272   const char BaseIndent[] = "            ";
 273   OS << BaseIndent;
 274   OS.indent(Indent + 2);
 275   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
 276
 277   if (DumpOpts.Verbose || DumpOpts.ShowForm)
 278     OS << formatv(" [{0}]", Form);
 279
 280   DWARFUnit *U = Die.getDwarfUnit();
 281   DWARFFormValue FormValue = DWARFFormValue::createFromUnit(Form, U, OffsetPtr);
 282
 283   OS << "\t(";
 284
 285   StringRef Name;
 286   std::string File;
 287   auto Color = HighlightColor::Enumerator;
 288   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
 289     Color = HighlightColor::String;
 290     if (const auto *LT = U->getContext().getLineTableForUnit(U))
 291       if (LT->getFileNameByIndex(
 292               FormValue.getAsUnsignedConstant().getValue(),
 293               U->getCompilationDir(),
 294               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
 295         File = '"' + File + '"';
 296         Name = File;
 297       }
 298   } else if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
 299     Name = AttributeValueString(Attr, *Val);
 300
 301   if (!Name.empty())
 302     WithColor(OS, Color) << Name;
 303   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
 304     OS << *FormValue.getAsUnsignedConstant();
 305   else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
 306            FormValue.getAsUnsignedConstant()) {
 307     if (DumpOpts.ShowAddresses) {
 308       // Print the actual address rather than the offset.
 309       uint64_t LowPC, HighPC, Index;
 310       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
 311         OS << format("0x%016" PRIx64, HighPC);
 312       else
 313         FormValue.dump(OS, DumpOpts);
 314     }
 315   } else if (DWARFAttribute::mayHaveLocationDescription(Attr))
 316     dumpLocation(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4, DumpOpts);
 317   else
 318     FormValue.dump(OS, DumpOpts);
 319
 320   std::string Space = DumpOpts.ShowAddresses ? " " : "";
 321
 322   // We have dumped the attribute raw value. For some attributes
 323   // having both the raw value and the pretty-printed value is
 324   // interesting. These attributes are handled below.
 325   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
 326     if (const char *Name =
 327             Die.getAttributeValueAsReferencedDie(FormValue).getName(
 328                 DINameKind::LinkageName))
 329       OS << Space << "\"" << Name << '\"';
 330   } else if (Attr == DW_AT_type) {
 331     OS << Space << "\"";
 332     dumpTypeName(OS, Die.getAttributeValueAsReferencedDie(FormValue));
 333     OS << '"';
 334   } else if (Attr == DW_AT_APPLE_property_attribute) {
 335     if (Optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
 336       dumpApplePropertyAttribute(OS, *OptVal);
 337   } else if (Attr == DW_AT_ranges) {
 338     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
 339     // For DW_FORM_rnglistx we need to dump the offset separately, since
 340     // we have only dumped the index so far.
 341     if (FormValue.getForm() == DW_FORM_rnglistx)
 342       if (auto RangeListOffset =
 343               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
 344         DWARFFormValue FV = DWARFFormValue::createFromUValue(
 345             dwarf::DW_FORM_sec_offset, *RangeListOffset);
 346         FV.dump(OS, DumpOpts);
 347       }
 348     if (auto RangesOrError = Die.getAddressRanges())
 349       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
 350                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
 351     else
 352       WithColor::error() << "decoding address ranges: "
 353                          << toString(RangesOrError.takeError()) << '\n';
 354   }
 355
 356   OS << ")\n";
 357 }
 358
 359 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
 360
 361 bool DWARFDie::isSubroutineDIE() const {
 362   auto Tag = getTag();
 363   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
 364 }
 365
 366 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
 367   if (!isValid())
 368     return None;
 369   auto AbbrevDecl = getAbbreviationDeclarationPtr();
 370   if (AbbrevDecl)
 371     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
 372   return None;
 373 }
 374
 375 Optional<DWARFFormValue>
 376 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
 377   if (!isValid())
 378     return None;
 379   auto AbbrevDecl = getAbbreviationDeclarationPtr();
 380   if (AbbrevDecl) {
 381     for (auto Attr : Attrs) {
 382       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
 383         return Value;
 384     }
 385   }
 386   return None;
 387 }
 388
 389 Optional<DWARFFormValue>
 390 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
 391   std::vector<DWARFDie> Worklist;
 392   Worklist.push_back(*this);
 393
 394   // Keep track if DIEs already seen to prevent infinite recursion.
 395   // Empirically we rarely see a depth of more than 3 when dealing with valid
 396   // DWARF. This corresponds to following the DW_AT_abstract_origin and
 397   // DW_AT_specification just once.
 398   SmallSet<DWARFDie, 3> Seen;
 399   Seen.insert(*this);
 400
 401   while (!Worklist.empty()) {
 402     DWARFDie Die = Worklist.back();
 403     Worklist.pop_back();
 404
 405     if (!Die.isValid())
 406       continue;
 407
 408     if (auto Value = Die.find(Attrs))
 409       return Value;
 410
 411     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
 412       if (Seen.insert(D).second)
 413         Worklist.push_back(D);
 414
 415     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
 416       if (Seen.insert(D).second)
 417         Worklist.push_back(D);
 418   }
 419
 420   return None;
 421 }
 422
 423 DWARFDie
 424 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
 425   if (Optional<DWARFFormValue> F = find(Attr))
 426     return getAttributeValueAsReferencedDie(*F);
 427   return DWARFDie();
 428 }
 429
 430 DWARFDie
 431 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
 432   if (auto SpecRef = V.getAsRelativeReference()) {
 433     if (SpecRef->Unit)
 434       return SpecRef->Unit->getDIEForOffset(SpecRef->Unit->getOffset() + SpecRef->Offset);
 435     if (auto SpecUnit = U->getUnitVector().getUnitForOffset(SpecRef->Offset))
 436       return SpecUnit->getDIEForOffset(SpecRef->Offset);
 437   }
 438   return DWARFDie();
 439 }
 440
 441 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
 442   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
 443 }
 444
 445 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
 446   if (auto FormValue = find(DW_AT_high_pc)) {
 447     if (auto Address = FormValue->getAsAddress()) {
 448       // High PC is an address.
 449       return Address;
 450     }
 451     if (auto Offset = FormValue->getAsUnsignedConstant()) {
 452       // High PC is an offset from LowPC.
 453       return LowPC + *Offset;
 454     }
 455   }
 456   return None;
 457 }
 458
 459 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
 460                                uint64_t &SectionIndex) const {
 461   auto F = find(DW_AT_low_pc);
 462   auto LowPcAddr = toSectionedAddress(F);
 463   if (!LowPcAddr)
 464     return false;
 465   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
 466     LowPC = LowPcAddr->Address;
 467     HighPC = *HighPcAddr;
 468     SectionIndex = LowPcAddr->SectionIndex;
 469     return true;
 470   }
 471   return false;
 472 }
 473
 474 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
 475   if (isNULL())
 476     return DWARFAddressRangesVector();
 477   // Single range specified by low/high PC.
 478   uint64_t LowPC, HighPC, Index;
 479   if (getLowAndHighPC(LowPC, HighPC, Index))
 480     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
 481
 482   Optional<DWARFFormValue> Value = find(DW_AT_ranges);
 483   if (Value) {
 484     if (Value->getForm() == DW_FORM_rnglistx)
 485       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
 486     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
 487   }
 488   return DWARFAddressRangesVector();
 489 }
 490
 491 void DWARFDie::collectChildrenAddressRanges(
 492     DWARFAddressRangesVector &Ranges) const {
 493   if (isNULL())
 494     return;
 495   if (isSubprogramDIE()) {
 496     if (auto DIERangesOrError = getAddressRanges())
 497       Ranges.insert(Ranges.end(), DIERangesOrError.get().begin(),
 498                     DIERangesOrError.get().end());
 499     else
 500       llvm::consumeError(DIERangesOrError.takeError());
 501   }
 502
 503   for (auto Child : children())
 504     Child.collectChildrenAddressRanges(Ranges);
 505 }
 506
 507 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
 508   auto RangesOrError = getAddressRanges();
 509   if (!RangesOrError) {
 510     llvm::consumeError(RangesOrError.takeError());
 511     return false;
 512   }
 513
 514   for (const auto &R : RangesOrError.get())
 515     if (R.LowPC <= Address && Address < R.HighPC)
 516       return true;
 517   return false;
 518 }
 519
 520 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
 521   if (!isSubroutineDIE())
 522     return nullptr;
 523   return getName(Kind);
 524 }
 525
 526 const char *DWARFDie::getName(DINameKind Kind) const {
 527   if (!isValid() || Kind == DINameKind::None)
 528     return nullptr;
 529   // Try to get mangled name only if it was asked for.
 530   if (Kind == DINameKind::LinkageName) {
 531     if (auto Name = dwarf::toString(
 532             findRecursively({DW_AT_MIPS_linkage_name, DW_AT_linkage_name}),
 533             nullptr))
 534       return Name;
 535   }
 536   if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
 537     return Name;
 538   return nullptr;
 539 }
 540
 541 uint64_t DWARFDie::getDeclLine() const {
 542   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
 543 }
 544
 545 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
 546                               uint32_t &CallColumn,
 547                               uint32_t &CallDiscriminator) const {
 548   CallFile = toUnsigned(find(DW_AT_call_file), 0);
 549   CallLine = toUnsigned(find(DW_AT_call_line), 0);
 550   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
 551   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
 552 }
 553
 554 /// Helper to dump a DIE with all of its parents, but no siblings.
 555 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
 556                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
 557   if (!Die)
 558     return Indent;
 559   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
 560     return Indent;
 561   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
 562   Die.dump(OS, Indent, DumpOpts);
 563   return Indent + 2;
 564 }
 565
 566 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
 567                     DIDumpOptions DumpOpts) const {
 568   if (!isValid())
 569     return;
 570   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
 571   const uint64_t Offset = getOffset();
 572   uint64_t offset = Offset;
 573   if (DumpOpts.ShowParents) {
 574     DIDumpOptions ParentDumpOpts = DumpOpts;
 575     ParentDumpOpts.ShowParents = false;
 576     ParentDumpOpts.ShowChildren = false;
 577     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
 578   }
 579
 580   if (debug_info_data.isValidOffset(offset)) {
 581     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
 582     if (DumpOpts.ShowAddresses)
 583       WithColor(OS, HighlightColor::Address).get()
 584           << format("\n0x%8.8" PRIx64 ": ", Offset);
 585
 586     if (abbrCode) {
 587       auto AbbrevDecl = getAbbreviationDeclarationPtr();
 588       if (AbbrevDecl) {
 589         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
 590             << formatv("{0}", getTag());
 591         if (DumpOpts.Verbose)
 592           OS << format(" [%u] %c", abbrCode,
 593                        AbbrevDecl->hasChildren() ? '*' : ' ');
 594         OS << '\n';
 595
 596         // Dump all data in the DIE for the attributes.
 597         for (const auto &AttrSpec : AbbrevDecl->attributes()) {
 598           if (AttrSpec.Form == DW_FORM_implicit_const) {
 599             // We are dumping .debug_info section ,
 600             // implicit_const attribute values are not really stored here,
 601             // but in .debug_abbrev section. So we just skip such attrs.
 602             continue;
 603           }
 604           dumpAttribute(OS, *this, &offset, AttrSpec.Attr, AttrSpec.Form,
 605                         Indent, DumpOpts);
 606         }
 607
 608         DWARFDie child = getFirstChild();
 609         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0 && child) {
 610           DumpOpts.ChildRecurseDepth--;
 611           DIDumpOptions ChildDumpOpts = DumpOpts;
 612           ChildDumpOpts.ShowParents = false;
 613           while (child) {
 614             child.dump(OS, Indent + 2, ChildDumpOpts);
 615             child = child.getSibling();
 616           }
 617         }
 618       } else {
 619         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
 620            << abbrCode << '\n';
 621       }
 622     } else {
 623       OS.indent(Indent) << "NULL\n";
 624     }
 625   }
 626 }
 627
 628 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
 629
 630 DWARFDie DWARFDie::getParent() const {
 631   if (isValid())
 632     return U->getParent(Die);
 633   return DWARFDie();
 634 }
 635
 636 DWARFDie DWARFDie::getSibling() const {
 637   if (isValid())
 638     return U->getSibling(Die);
 639   return DWARFDie();
 640 }
 641
 642 DWARFDie DWARFDie::getPreviousSibling() const {
 643   if (isValid())
 644     return U->getPreviousSibling(Die);
 645   return DWARFDie();
 646 }
 647
 648 DWARFDie DWARFDie::getFirstChild() const {
 649   if (isValid())
 650     return U->getFirstChild(Die);
 651   return DWARFDie();
 652 }
 653
 654 DWARFDie DWARFDie::getLastChild() const {
 655   if (isValid())
 656     return U->getLastChild(Die);
 657   return DWARFDie();
 658 }
 659
 660 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
 661   return make_range(attribute_iterator(*this, false),
 662                     attribute_iterator(*this, true));
 663 }
 664
 665 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
 666     : Die(D), Index(0) {
 667   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
 668   assert(AbbrDecl && "Must have abbreviation declaration");
 669   if (End) {
 670     // This is the end iterator so we set the index to the attribute count.
 671     Index = AbbrDecl->getNumAttributes();
 672   } else {
 673     // This is the begin iterator so we extract the value for this->Index.
 674     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
 675     updateForIndex(*AbbrDecl, 0);
 676   }
 677 }
 678
 679 void DWARFDie::attribute_iterator::updateForIndex(
 680     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
 681   Index = I;
 682   // AbbrDecl must be valid before calling this function.
 683   auto NumAttrs = AbbrDecl.getNumAttributes();
 684   if (Index < NumAttrs) {
 685     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
 686     // Add the previous byte size of any previous attribute value.
 687     AttrValue.Offset += AttrValue.ByteSize;
 688     uint64_t ParseOffset = AttrValue.Offset;
 689     auto U = Die.getDwarfUnit();
 690     assert(U && "Die must have valid DWARF unit");
 691     AttrValue.Value = DWARFFormValue::createFromUnit(
 692         AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
 693     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
 694   } else {
 695     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
 696     AttrValue = {};
 697   }
 698 }
 699
 700 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
 701   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
 702     updateForIndex(*AbbrDecl, Index + 1);
 703   return *this;
 704 }
 705
 706 bool DWARFAttribute::mayHaveLocationDescription(dwarf::Attribute Attr) {
 707   switch (Attr) {
 708   // From the DWARF v5 specification.
 709   case DW_AT_location:
 710   case DW_AT_byte_size:
 711   case DW_AT_bit_size:
 712   case DW_AT_string_length:
 713   case DW_AT_lower_bound:
 714   case DW_AT_return_addr:
 715   case DW_AT_bit_stride:
 716   case DW_AT_upper_bound:
 717   case DW_AT_count:
 718   case DW_AT_data_member_location:
 719   case DW_AT_frame_base:
 720   case DW_AT_segment:
 721   case DW_AT_static_link:
 722   case DW_AT_use_location:
 723   case DW_AT_vtable_elem_location:
 724   case DW_AT_allocated:
 725   case DW_AT_associated:
 726   case DW_AT_byte_stride:
 727   case DW_AT_rank:
 728   case DW_AT_call_value:
 729   case DW_AT_call_origin:
 730   case DW_AT_call_target:
 731   case DW_AT_call_target_clobbered:
 732   case DW_AT_call_data_location:
 733   case DW_AT_call_data_value:
 734   // Extensions.
 735   case DW_AT_GNU_call_site_value:
 736   case DW_AT_GNU_call_site_target:
 737     return true;
 738   default:
 739     return false;
 740   }
 741 }