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/DWARFDebugLine.h"
18 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
19 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
20 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
21 #include "llvm/DebugInfo/DWARF/DWARFTypePrinter.h"
22 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
23 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
24 #include "llvm/Object/ObjectFile.h"
25 #include "llvm/Support/DataExtractor.h"
26 #include "llvm/Support/Format.h"
27 #include "llvm/Support/FormatVariadic.h"
28 #include "llvm/Support/MathExtras.h"
29 #include "llvm/Support/WithColor.h"
30 #include "llvm/Support/raw_ostream.h"
31 #include <cassert>
32 #include <cinttypes>
33 #include <cstdint>
34 #include <string>
35 #include <utility>
36 
37 using namespace llvm;
38 using namespace dwarf;
39 using namespace object;
40 
41 static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
42   OS << " (";
43   do {
44     uint64_t Shift = countTrailingZeros(Val);
45     assert(Shift < 64 && "undefined behavior");
46     uint64_t Bit = 1ULL << Shift;
47     auto PropName = ApplePropertyString(Bit);
48     if (!PropName.empty())
49       OS << PropName;
50     else
51       OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
52     if (!(Val ^= Bit))
53       break;
54     OS << ", ";
55   } while (true);
56   OS << ")";
57 }
58 
59 static void dumpRanges(const DWARFObject &Obj, raw_ostream &OS,
60                        const DWARFAddressRangesVector &Ranges,
61                        unsigned AddressSize, unsigned Indent,
62                        const DIDumpOptions &DumpOpts) {
63   if (!DumpOpts.ShowAddresses)
64     return;
65 
66   for (const DWARFAddressRange &R : Ranges) {
67     OS << '\n';
68     OS.indent(Indent);
69     R.dump(OS, AddressSize, DumpOpts, &Obj);
70   }
71 }
72 
73 static void dumpLocationList(raw_ostream &OS, const DWARFFormValue &FormValue,
74                              DWARFUnit *U, unsigned Indent,
75                              DIDumpOptions DumpOpts) {
76   assert(FormValue.isFormClass(DWARFFormValue::FC_SectionOffset) &&
77          "bad FORM for location list");
78   DWARFContext &Ctx = U->getContext();
79   const MCRegisterInfo *MRI = Ctx.getRegisterInfo();
80   uint64_t Offset = *FormValue.getAsSectionOffset();
81 
82   if (FormValue.getForm() == DW_FORM_loclistx) {
83     FormValue.dump(OS, DumpOpts);
84 
85     if (auto LoclistOffset = U->getLoclistOffset(Offset))
86       Offset = *LoclistOffset;
87     else
88       return;
89   }
90   U->getLocationTable().dumpLocationList(&Offset, OS, U->getBaseAddress(), MRI,
91                                          Ctx.getDWARFObj(), U, DumpOpts,
92                                          Indent);
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 }
109 
110 static DWARFDie resolveReferencedType(DWARFDie D, DWARFFormValue F) {
111   return D.getAttributeValueAsReferencedDie(F).resolveTypeUnitReference();
112 }
113 
114 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
115                           const DWARFAttribute &AttrValue, unsigned Indent,
116                           DIDumpOptions DumpOpts) {
117   if (!Die.isValid())
118     return;
119   const char BaseIndent[] = "            ";
120   OS << BaseIndent;
121   OS.indent(Indent + 2);
122   dwarf::Attribute Attr = AttrValue.Attr;
123   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
124 
125   dwarf::Form Form = AttrValue.Value.getForm();
126   if (DumpOpts.Verbose || DumpOpts.ShowForm)
127     OS << formatv(" [{0}]", Form);
128 
129   DWARFUnit *U = Die.getDwarfUnit();
130   const DWARFFormValue &FormValue = AttrValue.Value;
131 
132   OS << "\t(";
133 
134   StringRef Name;
135   std::string File;
136   auto Color = HighlightColor::Enumerator;
137   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
138     Color = HighlightColor::String;
139     if (const auto *LT = U->getContext().getLineTableForUnit(U))
140       if (LT->getFileNameByIndex(
141               *FormValue.getAsUnsignedConstant(), U->getCompilationDir(),
142               DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
143         File = '"' + File + '"';
144         Name = File;
145       }
146   } else if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
147     Name = AttributeValueString(Attr, *Val);
148 
149   if (!Name.empty())
150     WithColor(OS, Color) << Name;
151   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
152     OS << *FormValue.getAsUnsignedConstant();
153   else if (Attr == DW_AT_low_pc &&
154            (FormValue.getAsAddress() ==
155             dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
156     if (DumpOpts.Verbose) {
157       FormValue.dump(OS, DumpOpts);
158       OS << " (";
159     }
160     OS << "dead code";
161     if (DumpOpts.Verbose)
162       OS << ')';
163   } else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
164              FormValue.getAsUnsignedConstant()) {
165     if (DumpOpts.ShowAddresses) {
166       // Print the actual address rather than the offset.
167       uint64_t LowPC, HighPC, Index;
168       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
169         DWARFFormValue::dumpAddress(OS, U->getAddressByteSize(), HighPC);
170       else
171         FormValue.dump(OS, DumpOpts);
172     }
173   } else if (DWARFAttribute::mayHaveLocationList(Attr) &&
174              FormValue.isFormClass(DWARFFormValue::FC_SectionOffset))
175     dumpLocationList(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
176                      DumpOpts);
177   else if (FormValue.isFormClass(DWARFFormValue::FC_Exprloc) ||
178            (DWARFAttribute::mayHaveLocationExpr(Attr) &&
179             FormValue.isFormClass(DWARFFormValue::FC_Block)))
180     dumpLocationExpr(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
181                      DumpOpts);
182   else
183     FormValue.dump(OS, DumpOpts);
184 
185   std::string Space = DumpOpts.ShowAddresses ? " " : "";
186 
187   // We have dumped the attribute raw value. For some attributes
188   // having both the raw value and the pretty-printed value is
189   // interesting. These attributes are handled below.
190   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
191     if (const char *Name =
192             Die.getAttributeValueAsReferencedDie(FormValue).getName(
193                 DINameKind::LinkageName))
194       OS << Space << "\"" << Name << '\"';
195   } else if (Attr == DW_AT_type || Attr == DW_AT_containing_type) {
196     DWARFDie D = resolveReferencedType(Die, FormValue);
197     if (D && !D.isNULL()) {
198       OS << Space << "\"";
199       dumpTypeQualifiedName(D, OS);
200       OS << '"';
201     }
202   } else if (Attr == DW_AT_APPLE_property_attribute) {
203     if (Optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
204       dumpApplePropertyAttribute(OS, *OptVal);
205   } else if (Attr == DW_AT_ranges) {
206     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
207     // For DW_FORM_rnglistx we need to dump the offset separately, since
208     // we have only dumped the index so far.
209     if (FormValue.getForm() == DW_FORM_rnglistx)
210       if (auto RangeListOffset =
211               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
212         DWARFFormValue FV = DWARFFormValue::createFromUValue(
213             dwarf::DW_FORM_sec_offset, *RangeListOffset);
214         FV.dump(OS, DumpOpts);
215       }
216     if (auto RangesOrError = Die.getAddressRanges())
217       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
218                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
219     else
220       DumpOpts.RecoverableErrorHandler(createStringError(
221           errc::invalid_argument, "decoding address ranges: %s",
222           toString(RangesOrError.takeError()).c_str()));
223   }
224 
225   OS << ")\n";
226 }
227 
228 void DWARFDie::getFullName(raw_string_ostream &OS,
229                            std::string *OriginalFullName) const {
230   const char *NamePtr = getShortName();
231   if (!NamePtr)
232     return;
233   if (getTag() == DW_TAG_GNU_template_parameter_pack)
234     return;
235   dumpTypeUnqualifiedName(*this, OS, OriginalFullName);
236 }
237 
238 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
239 
240 bool DWARFDie::isSubroutineDIE() const {
241   auto Tag = getTag();
242   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
243 }
244 
245 Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
246   if (!isValid())
247     return None;
248   auto AbbrevDecl = getAbbreviationDeclarationPtr();
249   if (AbbrevDecl)
250     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
251   return None;
252 }
253 
254 Optional<DWARFFormValue>
255 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
256   if (!isValid())
257     return None;
258   auto AbbrevDecl = getAbbreviationDeclarationPtr();
259   if (AbbrevDecl) {
260     for (auto Attr : Attrs) {
261       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
262         return Value;
263     }
264   }
265   return None;
266 }
267 
268 Optional<DWARFFormValue>
269 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
270   SmallVector<DWARFDie, 3> Worklist;
271   Worklist.push_back(*this);
272 
273   // Keep track if DIEs already seen to prevent infinite recursion.
274   // Empirically we rarely see a depth of more than 3 when dealing with valid
275   // DWARF. This corresponds to following the DW_AT_abstract_origin and
276   // DW_AT_specification just once.
277   SmallSet<DWARFDie, 3> Seen;
278   Seen.insert(*this);
279 
280   while (!Worklist.empty()) {
281     DWARFDie Die = Worklist.pop_back_val();
282 
283     if (!Die.isValid())
284       continue;
285 
286     if (auto Value = Die.find(Attrs))
287       return Value;
288 
289     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
290       if (Seen.insert(D).second)
291         Worklist.push_back(D);
292 
293     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
294       if (Seen.insert(D).second)
295         Worklist.push_back(D);
296   }
297 
298   return None;
299 }
300 
301 DWARFDie
302 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
303   if (Optional<DWARFFormValue> F = find(Attr))
304     return getAttributeValueAsReferencedDie(*F);
305   return DWARFDie();
306 }
307 
308 DWARFDie
309 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
310   DWARFDie Result;
311   if (auto SpecRef = V.getAsRelativeReference()) {
312     if (SpecRef->Unit)
313       Result = SpecRef->Unit->getDIEForOffset(SpecRef->Unit->getOffset() +
314                                               SpecRef->Offset);
315     else if (auto SpecUnit =
316                  U->getUnitVector().getUnitForOffset(SpecRef->Offset))
317       Result = SpecUnit->getDIEForOffset(SpecRef->Offset);
318   }
319   return Result;
320 }
321 
322 DWARFDie DWARFDie::resolveTypeUnitReference() const {
323   if (auto Attr = find(DW_AT_signature)) {
324     if (Optional<uint64_t> Sig = Attr->getAsReferenceUVal()) {
325       if (DWARFTypeUnit *TU = U->getContext().getTypeUnitForHash(
326               U->getVersion(), *Sig, U->isDWOUnit()))
327         return TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
328     }
329   }
330   return *this;
331 }
332 
333 Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
334   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
335 }
336 
337 Optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
338   return toSectionOffset(find(DW_AT_loclists_base));
339 }
340 
341 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
342   uint64_t Tombstone = dwarf::computeTombstoneAddress(U->getAddressByteSize());
343   if (LowPC == Tombstone)
344     return None;
345   if (auto FormValue = find(DW_AT_high_pc)) {
346     if (auto Address = FormValue->getAsAddress()) {
347       // High PC is an address.
348       return Address;
349     }
350     if (auto Offset = FormValue->getAsUnsignedConstant()) {
351       // High PC is an offset from LowPC.
352       return LowPC + *Offset;
353     }
354   }
355   return None;
356 }
357 
358 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
359                                uint64_t &SectionIndex) const {
360   auto F = find(DW_AT_low_pc);
361   auto LowPcAddr = toSectionedAddress(F);
362   if (!LowPcAddr)
363     return false;
364   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
365     LowPC = LowPcAddr->Address;
366     HighPC = *HighPcAddr;
367     SectionIndex = LowPcAddr->SectionIndex;
368     return true;
369   }
370   return false;
371 }
372 
373 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
374   if (isNULL())
375     return DWARFAddressRangesVector();
376   // Single range specified by low/high PC.
377   uint64_t LowPC, HighPC, Index;
378   if (getLowAndHighPC(LowPC, HighPC, Index))
379     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
380 
381   Optional<DWARFFormValue> Value = find(DW_AT_ranges);
382   if (Value) {
383     if (Value->getForm() == DW_FORM_rnglistx)
384       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
385     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
386   }
387   return DWARFAddressRangesVector();
388 }
389 
390 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
391   auto RangesOrError = getAddressRanges();
392   if (!RangesOrError) {
393     llvm::consumeError(RangesOrError.takeError());
394     return false;
395   }
396 
397   for (const auto &R : RangesOrError.get())
398     if (R.LowPC <= Address && Address < R.HighPC)
399       return true;
400   return false;
401 }
402 
403 Expected<DWARFLocationExpressionsVector>
404 DWARFDie::getLocations(dwarf::Attribute Attr) const {
405   Optional<DWARFFormValue> Location = find(Attr);
406   if (!Location)
407     return createStringError(inconvertibleErrorCode(), "No %s",
408                              dwarf::AttributeString(Attr).data());
409 
410   if (Optional<uint64_t> Off = Location->getAsSectionOffset()) {
411     uint64_t Offset = *Off;
412 
413     if (Location->getForm() == DW_FORM_loclistx) {
414       if (auto LoclistOffset = U->getLoclistOffset(Offset))
415         Offset = *LoclistOffset;
416       else
417         return createStringError(inconvertibleErrorCode(),
418                                  "Loclist table not found");
419     }
420     return U->findLoclistFromOffset(Offset);
421   }
422 
423   if (Optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
424     return DWARFLocationExpressionsVector{
425         DWARFLocationExpression{None, to_vector<4>(*Expr)}};
426   }
427 
428   return createStringError(
429       inconvertibleErrorCode(), "Unsupported %s encoding: %s",
430       dwarf::AttributeString(Attr).data(),
431       dwarf::FormEncodingString(Location->getForm()).data());
432 }
433 
434 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
435   if (!isSubroutineDIE())
436     return nullptr;
437   return getName(Kind);
438 }
439 
440 const char *DWARFDie::getName(DINameKind Kind) const {
441   if (!isValid() || Kind == DINameKind::None)
442     return nullptr;
443   // Try to get mangled name only if it was asked for.
444   if (Kind == DINameKind::LinkageName) {
445     if (auto Name = getLinkageName())
446       return Name;
447   }
448   return getShortName();
449 }
450 
451 const char *DWARFDie::getShortName() const {
452   if (!isValid())
453     return nullptr;
454 
455   return dwarf::toString(findRecursively(dwarf::DW_AT_name), nullptr);
456 }
457 
458 const char *DWARFDie::getLinkageName() const {
459   if (!isValid())
460     return nullptr;
461 
462   return dwarf::toString(findRecursively({dwarf::DW_AT_MIPS_linkage_name,
463                                           dwarf::DW_AT_linkage_name}),
464                          nullptr);
465 }
466 
467 uint64_t DWARFDie::getDeclLine() const {
468   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
469 }
470 
471 std::string
472 DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
473   if (auto FormValue = findRecursively(DW_AT_decl_file))
474     if (auto OptString = FormValue->getAsFile(Kind))
475       return *OptString;
476   return {};
477 }
478 
479 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
480                               uint32_t &CallColumn,
481                               uint32_t &CallDiscriminator) const {
482   CallFile = toUnsigned(find(DW_AT_call_file), 0);
483   CallLine = toUnsigned(find(DW_AT_call_line), 0);
484   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
485   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
486 }
487 
488 Optional<uint64_t> DWARFDie::getTypeSize(uint64_t PointerSize) {
489   if (auto SizeAttr = find(DW_AT_byte_size))
490     if (Optional<uint64_t> Size = SizeAttr->getAsUnsignedConstant())
491       return Size;
492 
493   switch (getTag()) {
494   case DW_TAG_pointer_type:
495   case DW_TAG_reference_type:
496   case DW_TAG_rvalue_reference_type:
497     return PointerSize;
498   case DW_TAG_ptr_to_member_type: {
499     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
500       if (BaseType.getTag() == DW_TAG_subroutine_type)
501         return 2 * PointerSize;
502     return PointerSize;
503   }
504   case DW_TAG_const_type:
505   case DW_TAG_immutable_type:
506   case DW_TAG_volatile_type:
507   case DW_TAG_restrict_type:
508   case DW_TAG_typedef: {
509     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
510       return BaseType.getTypeSize(PointerSize);
511     break;
512   }
513   case DW_TAG_array_type: {
514     DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type);
515     if (!BaseType)
516       return None;
517     Optional<uint64_t> BaseSize = BaseType.getTypeSize(PointerSize);
518     if (!BaseSize)
519       return None;
520     uint64_t Size = *BaseSize;
521     for (DWARFDie Child : *this) {
522       if (Child.getTag() != DW_TAG_subrange_type)
523         continue;
524 
525       if (auto ElemCountAttr = Child.find(DW_AT_count))
526         if (Optional<uint64_t> ElemCount =
527                 ElemCountAttr->getAsUnsignedConstant())
528           Size *= *ElemCount;
529       if (auto UpperBoundAttr = Child.find(DW_AT_upper_bound))
530         if (Optional<int64_t> UpperBound =
531                 UpperBoundAttr->getAsSignedConstant()) {
532           int64_t LowerBound = 0;
533           if (auto LowerBoundAttr = Child.find(DW_AT_lower_bound))
534             LowerBound = LowerBoundAttr->getAsSignedConstant().value_or(0);
535           Size *= *UpperBound - LowerBound + 1;
536         }
537     }
538     return Size;
539   }
540   default:
541     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
542       return BaseType.getTypeSize(PointerSize);
543     break;
544   }
545   return None;
546 }
547 
548 /// Helper to dump a DIE with all of its parents, but no siblings.
549 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
550                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
551   if (!Die)
552     return Indent;
553   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
554     return Indent;
555   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
556   Die.dump(OS, Indent, DumpOpts);
557   return Indent + 2;
558 }
559 
560 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
561                     DIDumpOptions DumpOpts) const {
562   if (!isValid())
563     return;
564   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
565   const uint64_t Offset = getOffset();
566   uint64_t offset = Offset;
567   if (DumpOpts.ShowParents) {
568     DIDumpOptions ParentDumpOpts = DumpOpts;
569     ParentDumpOpts.ShowParents = false;
570     ParentDumpOpts.ShowChildren = false;
571     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
572   }
573 
574   if (debug_info_data.isValidOffset(offset)) {
575     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
576     if (DumpOpts.ShowAddresses)
577       WithColor(OS, HighlightColor::Address).get()
578           << format("\n0x%8.8" PRIx64 ": ", Offset);
579 
580     if (abbrCode) {
581       auto AbbrevDecl = getAbbreviationDeclarationPtr();
582       if (AbbrevDecl) {
583         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
584             << formatv("{0}", getTag());
585         if (DumpOpts.Verbose) {
586           OS << format(" [%u] %c", abbrCode,
587                        AbbrevDecl->hasChildren() ? '*' : ' ');
588           if (Optional<uint32_t> ParentIdx = Die->getParentIdx())
589             OS << format(" (0x%8.8" PRIx64 ")",
590                          U->getDIEAtIndex(*ParentIdx).getOffset());
591         }
592         OS << '\n';
593 
594         // Dump all data in the DIE for the attributes.
595         for (const DWARFAttribute &AttrValue : attributes())
596           dumpAttribute(OS, *this, AttrValue, Indent, DumpOpts);
597 
598         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0) {
599           DWARFDie Child = getFirstChild();
600           DumpOpts.ChildRecurseDepth--;
601           DIDumpOptions ChildDumpOpts = DumpOpts;
602           ChildDumpOpts.ShowParents = false;
603           while (Child) {
604             Child.dump(OS, Indent + 2, ChildDumpOpts);
605             Child = Child.getSibling();
606           }
607         }
608       } else {
609         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
610            << abbrCode << '\n';
611       }
612     } else {
613       OS.indent(Indent) << "NULL\n";
614     }
615   }
616 }
617 
618 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
619 
620 DWARFDie DWARFDie::getParent() const {
621   if (isValid())
622     return U->getParent(Die);
623   return DWARFDie();
624 }
625 
626 DWARFDie DWARFDie::getSibling() const {
627   if (isValid())
628     return U->getSibling(Die);
629   return DWARFDie();
630 }
631 
632 DWARFDie DWARFDie::getPreviousSibling() const {
633   if (isValid())
634     return U->getPreviousSibling(Die);
635   return DWARFDie();
636 }
637 
638 DWARFDie DWARFDie::getFirstChild() const {
639   if (isValid())
640     return U->getFirstChild(Die);
641   return DWARFDie();
642 }
643 
644 DWARFDie DWARFDie::getLastChild() const {
645   if (isValid())
646     return U->getLastChild(Die);
647   return DWARFDie();
648 }
649 
650 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
651   return make_range(attribute_iterator(*this, false),
652                     attribute_iterator(*this, true));
653 }
654 
655 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
656     : Die(D), Index(0) {
657   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
658   assert(AbbrDecl && "Must have abbreviation declaration");
659   if (End) {
660     // This is the end iterator so we set the index to the attribute count.
661     Index = AbbrDecl->getNumAttributes();
662   } else {
663     // This is the begin iterator so we extract the value for this->Index.
664     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
665     updateForIndex(*AbbrDecl, 0);
666   }
667 }
668 
669 void DWARFDie::attribute_iterator::updateForIndex(
670     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
671   Index = I;
672   // AbbrDecl must be valid before calling this function.
673   auto NumAttrs = AbbrDecl.getNumAttributes();
674   if (Index < NumAttrs) {
675     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
676     // Add the previous byte size of any previous attribute value.
677     AttrValue.Offset += AttrValue.ByteSize;
678     uint64_t ParseOffset = AttrValue.Offset;
679     if (AbbrDecl.getAttrIsImplicitConstByIndex(Index))
680       AttrValue.Value = DWARFFormValue::createFromSValue(
681           AbbrDecl.getFormByIndex(Index),
682           AbbrDecl.getAttrImplicitConstValueByIndex(Index));
683     else {
684       auto U = Die.getDwarfUnit();
685       assert(U && "Die must have valid DWARF unit");
686       AttrValue.Value = DWARFFormValue::createFromUnit(
687           AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
688     }
689     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
690   } else {
691     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
692     AttrValue = {};
693   }
694 }
695 
696 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
697   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
698     updateForIndex(*AbbrDecl, Index + 1);
699   return *this;
700 }
701 
702 bool DWARFAttribute::mayHaveLocationList(dwarf::Attribute Attr) {
703   switch(Attr) {
704   case DW_AT_location:
705   case DW_AT_string_length:
706   case DW_AT_return_addr:
707   case DW_AT_data_member_location:
708   case DW_AT_frame_base:
709   case DW_AT_static_link:
710   case DW_AT_segment:
711   case DW_AT_use_location:
712   case DW_AT_vtable_elem_location:
713     return true;
714   default:
715     return false;
716   }
717 }
718 
719 bool DWARFAttribute::mayHaveLocationExpr(dwarf::Attribute Attr) {
720   switch (Attr) {
721   // From the DWARF v5 specification.
722   case DW_AT_location:
723   case DW_AT_byte_size:
724   case DW_AT_bit_offset:
725   case DW_AT_bit_size:
726   case DW_AT_string_length:
727   case DW_AT_lower_bound:
728   case DW_AT_return_addr:
729   case DW_AT_bit_stride:
730   case DW_AT_upper_bound:
731   case DW_AT_count:
732   case DW_AT_data_member_location:
733   case DW_AT_frame_base:
734   case DW_AT_segment:
735   case DW_AT_static_link:
736   case DW_AT_use_location:
737   case DW_AT_vtable_elem_location:
738   case DW_AT_allocated:
739   case DW_AT_associated:
740   case DW_AT_data_location:
741   case DW_AT_byte_stride:
742   case DW_AT_rank:
743   case DW_AT_call_value:
744   case DW_AT_call_origin:
745   case DW_AT_call_target:
746   case DW_AT_call_target_clobbered:
747   case DW_AT_call_data_location:
748   case DW_AT_call_data_value:
749   // Extensions.
750   case DW_AT_GNU_call_site_value:
751   case DW_AT_GNU_call_site_target:
752     return true;
753   default:
754     return false;
755   }
756 }
757 
758 namespace llvm {
759 
760 void dumpTypeQualifiedName(const DWARFDie &DIE, raw_ostream &OS) {
761   DWARFTypePrinter(OS).appendQualifiedName(DIE);
762 }
763 
764 void dumpTypeUnqualifiedName(const DWARFDie &DIE, raw_ostream &OS,
765                              std::string *OriginalFullName) {
766   DWARFTypePrinter(OS).appendUnqualifiedName(DIE, OriginalFullName);
767 }
768 
769 } // namespace llvm
770