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