xref: /freebsd/contrib/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp (revision 7ef62cebc2f965b0f640263e179276928885e33d) 
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/SmallSet.h"
11 #include "llvm/ADT/StringRef.h"
12 #include "llvm/BinaryFormat/Dwarf.h"
13 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
14 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
15 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
16 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
17 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
18 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
19 #include "llvm/DebugInfo/DWARF/DWARFTypePrinter.h"
20 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
21 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/DataExtractor.h"
24 #include "llvm/Support/Format.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 <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   for (const DWARFAddressRange &R : Ranges) {
65     OS << '\n';
66     OS.indent(Indent);
67     R.dump(OS, AddressSize, DumpOpts, &Obj);
68   }
69 }
70 
71 static void dumpLocationList(raw_ostream &OS, const DWARFFormValue &FormValue,
72                              DWARFUnit *U, unsigned Indent,
73                              DIDumpOptions DumpOpts) {
74   assert(FormValue.isFormClass(DWARFFormValue::FC_SectionOffset) &&
75          "bad FORM for location list");
76   DWARFContext &Ctx = U->getContext();
77   uint64_t Offset = *FormValue.getAsSectionOffset();
78 
79   if (FormValue.getForm() == DW_FORM_loclistx) {
80     FormValue.dump(OS, DumpOpts);
81 
82     if (auto LoclistOffset = U->getLoclistOffset(Offset))
83       Offset = *LoclistOffset;
84     else
85       return;
86   }
87   U->getLocationTable().dumpLocationList(
88       &Offset, OS, U->getBaseAddress(), Ctx.getDWARFObj(), U, DumpOpts, Indent);
89 }
90 
91 static void dumpLocationExpr(raw_ostream &OS, const DWARFFormValue &FormValue,
92                              DWARFUnit *U, unsigned Indent,
93                              DIDumpOptions DumpOpts) {
94   assert((FormValue.isFormClass(DWARFFormValue::FC_Block) ||
95           FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) &&
96          "bad FORM for location expression");
97   DWARFContext &Ctx = U->getContext();
98   ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
99   DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
100                      Ctx.isLittleEndian(), 0);
101   DWARFExpression(Data, U->getAddressByteSize(), U->getFormParams().Format)
102       .print(OS, DumpOpts, U);
103 }
104 
105 static DWARFDie resolveReferencedType(DWARFDie D, DWARFFormValue F) {
106   return D.getAttributeValueAsReferencedDie(F).resolveTypeUnitReference();
107 }
108 
109 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
110                           const DWARFAttribute &AttrValue, unsigned Indent,
111                           DIDumpOptions DumpOpts) {
112   if (!Die.isValid())
113     return;
114   const char BaseIndent[] = "            ";
115   OS << BaseIndent;
116   OS.indent(Indent + 2);
117   dwarf::Attribute Attr = AttrValue.Attr;
118   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
119 
120   dwarf::Form Form = AttrValue.Value.getForm();
121   if (DumpOpts.Verbose || DumpOpts.ShowForm)
122     OS << formatv(" [{0}]", Form);
123 
124   DWARFUnit *U = Die.getDwarfUnit();
125   const DWARFFormValue &FormValue = AttrValue.Value;
126 
127   OS << "\t(";
128 
129   StringRef Name;
130   std::string File;
131   auto Color = HighlightColor::Enumerator;
132   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
133     Color = HighlightColor::String;
134     if (const auto *LT = U->getContext().getLineTableForUnit(U)) {
135       if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant()) {
136         if (LT->getFileNameByIndex(
137                 *Val, U->getCompilationDir(),
138                 DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
139                 File)) {
140           File = '"' + File + '"';
141           Name = File;
142         }
143       }
144     }
145   } else if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
146     Name = AttributeValueString(Attr, *Val);
147 
148   if (!Name.empty())
149     WithColor(OS, Color) << Name;
150   else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line) {
151     if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
152       OS << *Val;
153     else
154       FormValue.dump(OS, DumpOpts);
155   } else if (Attr == DW_AT_low_pc &&
156              (FormValue.getAsAddress() ==
157               dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
158     if (DumpOpts.Verbose) {
159       FormValue.dump(OS, DumpOpts);
160       OS << " (";
161     }
162     OS << "dead code";
163     if (DumpOpts.Verbose)
164       OS << ')';
165   } else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
166              FormValue.getAsUnsignedConstant()) {
167     if (DumpOpts.ShowAddresses) {
168       // Print the actual address rather than the offset.
169       uint64_t LowPC, HighPC, Index;
170       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
171         DWARFFormValue::dumpAddress(OS, U->getAddressByteSize(), HighPC);
172       else
173         FormValue.dump(OS, DumpOpts);
174     }
175   } else if (DWARFAttribute::mayHaveLocationList(Attr) &&
176              FormValue.isFormClass(DWARFFormValue::FC_SectionOffset))
177     dumpLocationList(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
178                      DumpOpts);
179   else if (FormValue.isFormClass(DWARFFormValue::FC_Exprloc) ||
180            (DWARFAttribute::mayHaveLocationExpr(Attr) &&
181             FormValue.isFormClass(DWARFFormValue::FC_Block)))
182     dumpLocationExpr(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
183                      DumpOpts);
184   else
185     FormValue.dump(OS, DumpOpts);
186 
187   std::string Space = DumpOpts.ShowAddresses ? " " : "";
188 
189   // We have dumped the attribute raw value. For some attributes
190   // having both the raw value and the pretty-printed value is
191   // interesting. These attributes are handled below.
192   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin) {
193     if (const char *Name =
194             Die.getAttributeValueAsReferencedDie(FormValue).getName(
195                 DINameKind::LinkageName))
196       OS << Space << "\"" << Name << '\"';
197   } else if (Attr == DW_AT_type || Attr == DW_AT_containing_type) {
198     DWARFDie D = resolveReferencedType(Die, FormValue);
199     if (D && !D.isNULL()) {
200       OS << Space << "\"";
201       dumpTypeQualifiedName(D, OS);
202       OS << '"';
203     }
204   } else if (Attr == DW_AT_APPLE_property_attribute) {
205     if (std::optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
206       dumpApplePropertyAttribute(OS, *OptVal);
207   } else if (Attr == DW_AT_ranges) {
208     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
209     // For DW_FORM_rnglistx we need to dump the offset separately, since
210     // we have only dumped the index so far.
211     if (FormValue.getForm() == DW_FORM_rnglistx)
212       if (auto RangeListOffset =
213               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
214         DWARFFormValue FV = DWARFFormValue::createFromUValue(
215             dwarf::DW_FORM_sec_offset, *RangeListOffset);
216         FV.dump(OS, DumpOpts);
217       }
218     if (auto RangesOrError = Die.getAddressRanges())
219       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
220                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
221     else
222       DumpOpts.RecoverableErrorHandler(createStringError(
223           errc::invalid_argument, "decoding address ranges: %s",
224           toString(RangesOrError.takeError()).c_str()));
225   }
226 
227   OS << ")\n";
228 }
229 
230 void DWARFDie::getFullName(raw_string_ostream &OS,
231                            std::string *OriginalFullName) const {
232   const char *NamePtr = getShortName();
233   if (!NamePtr)
234     return;
235   if (getTag() == DW_TAG_GNU_template_parameter_pack)
236     return;
237   dumpTypeUnqualifiedName(*this, OS, OriginalFullName);
238 }
239 
240 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
241 
242 bool DWARFDie::isSubroutineDIE() const {
243   auto Tag = getTag();
244   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
245 }
246 
247 std::optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
248   if (!isValid())
249     return std::nullopt;
250   auto AbbrevDecl = getAbbreviationDeclarationPtr();
251   if (AbbrevDecl)
252     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
253   return std::nullopt;
254 }
255 
256 std::optional<DWARFFormValue>
257 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
258   if (!isValid())
259     return std::nullopt;
260   auto AbbrevDecl = getAbbreviationDeclarationPtr();
261   if (AbbrevDecl) {
262     for (auto Attr : Attrs) {
263       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
264         return Value;
265     }
266   }
267   return std::nullopt;
268 }
269 
270 std::optional<DWARFFormValue>
271 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
272   SmallVector<DWARFDie, 3> Worklist;
273   Worklist.push_back(*this);
274 
275   // Keep track if DIEs already seen to prevent infinite recursion.
276   // Empirically we rarely see a depth of more than 3 when dealing with valid
277   // DWARF. This corresponds to following the DW_AT_abstract_origin and
278   // DW_AT_specification just once.
279   SmallSet<DWARFDie, 3> Seen;
280   Seen.insert(*this);
281 
282   while (!Worklist.empty()) {
283     DWARFDie Die = Worklist.pop_back_val();
284 
285     if (!Die.isValid())
286       continue;
287 
288     if (auto Value = Die.find(Attrs))
289       return Value;
290 
291     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
292       if (Seen.insert(D).second)
293         Worklist.push_back(D);
294 
295     if (auto D = Die.getAttributeValueAsReferencedDie(DW_AT_specification))
296       if (Seen.insert(D).second)
297         Worklist.push_back(D);
298   }
299 
300   return std::nullopt;
301 }
302 
303 DWARFDie
304 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
305   if (std::optional<DWARFFormValue> F = find(Attr))
306     return getAttributeValueAsReferencedDie(*F);
307   return DWARFDie();
308 }
309 
310 DWARFDie
311 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
312   DWARFDie Result;
313   if (auto SpecRef = V.getAsRelativeReference()) {
314     if (SpecRef->Unit)
315       Result = SpecRef->Unit->getDIEForOffset(SpecRef->Unit->getOffset() +
316                                               SpecRef->Offset);
317     else if (auto SpecUnit =
318                  U->getUnitVector().getUnitForOffset(SpecRef->Offset))
319       Result = SpecUnit->getDIEForOffset(SpecRef->Offset);
320   }
321   return Result;
322 }
323 
324 DWARFDie DWARFDie::resolveTypeUnitReference() const {
325   if (auto Attr = find(DW_AT_signature)) {
326     if (std::optional<uint64_t> Sig = Attr->getAsReferenceUVal()) {
327       if (DWARFTypeUnit *TU = U->getContext().getTypeUnitForHash(
328               U->getVersion(), *Sig, U->isDWOUnit()))
329         return TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
330     }
331   }
332   return *this;
333 }
334 
335 std::optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
336   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
337 }
338 
339 std::optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
340   return toSectionOffset(find(DW_AT_loclists_base));
341 }
342 
343 std::optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
344   uint64_t Tombstone = dwarf::computeTombstoneAddress(U->getAddressByteSize());
345   if (LowPC == Tombstone)
346     return std::nullopt;
347   if (auto FormValue = find(DW_AT_high_pc)) {
348     if (auto Address = FormValue->getAsAddress()) {
349       // High PC is an address.
350       return Address;
351     }
352     if (auto Offset = FormValue->getAsUnsignedConstant()) {
353       // High PC is an offset from LowPC.
354       return LowPC + *Offset;
355     }
356   }
357   return std::nullopt;
358 }
359 
360 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
361                                uint64_t &SectionIndex) const {
362   auto F = find(DW_AT_low_pc);
363   auto LowPcAddr = toSectionedAddress(F);
364   if (!LowPcAddr)
365     return false;
366   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
367     LowPC = LowPcAddr->Address;
368     HighPC = *HighPcAddr;
369     SectionIndex = LowPcAddr->SectionIndex;
370     return true;
371   }
372   return false;
373 }
374 
375 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
376   if (isNULL())
377     return DWARFAddressRangesVector();
378   // Single range specified by low/high PC.
379   uint64_t LowPC, HighPC, Index;
380   if (getLowAndHighPC(LowPC, HighPC, Index))
381     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
382 
383   std::optional<DWARFFormValue> Value = find(DW_AT_ranges);
384   if (Value) {
385     if (Value->getForm() == DW_FORM_rnglistx)
386       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
387     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
388   }
389   return DWARFAddressRangesVector();
390 }
391 
392 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
393   auto RangesOrError = getAddressRanges();
394   if (!RangesOrError) {
395     llvm::consumeError(RangesOrError.takeError());
396     return false;
397   }
398 
399   for (const auto &R : RangesOrError.get())
400     if (R.LowPC <= Address && Address < R.HighPC)
401       return true;
402   return false;
403 }
404 
405 Expected<DWARFLocationExpressionsVector>
406 DWARFDie::getLocations(dwarf::Attribute Attr) const {
407   std::optional<DWARFFormValue> Location = find(Attr);
408   if (!Location)
409     return createStringError(inconvertibleErrorCode(), "No %s",
410                              dwarf::AttributeString(Attr).data());
411 
412   if (std::optional<uint64_t> Off = Location->getAsSectionOffset()) {
413     uint64_t Offset = *Off;
414 
415     if (Location->getForm() == DW_FORM_loclistx) {
416       if (auto LoclistOffset = U->getLoclistOffset(Offset))
417         Offset = *LoclistOffset;
418       else
419         return createStringError(inconvertibleErrorCode(),
420                                  "Loclist table not found");
421     }
422     return U->findLoclistFromOffset(Offset);
423   }
424 
425   if (std::optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
426     return DWARFLocationExpressionsVector{
427         DWARFLocationExpression{std::nullopt, to_vector<4>(*Expr)}};
428   }
429 
430   return createStringError(
431       inconvertibleErrorCode(), "Unsupported %s encoding: %s",
432       dwarf::AttributeString(Attr).data(),
433       dwarf::FormEncodingString(Location->getForm()).data());
434 }
435 
436 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
437   if (!isSubroutineDIE())
438     return nullptr;
439   return getName(Kind);
440 }
441 
442 const char *DWARFDie::getName(DINameKind Kind) const {
443   if (!isValid() || Kind == DINameKind::None)
444     return nullptr;
445   // Try to get mangled name only if it was asked for.
446   if (Kind == DINameKind::LinkageName) {
447     if (auto Name = getLinkageName())
448       return Name;
449   }
450   return getShortName();
451 }
452 
453 const char *DWARFDie::getShortName() const {
454   if (!isValid())
455     return nullptr;
456 
457   return dwarf::toString(findRecursively(dwarf::DW_AT_name), nullptr);
458 }
459 
460 const char *DWARFDie::getLinkageName() const {
461   if (!isValid())
462     return nullptr;
463 
464   return dwarf::toString(findRecursively({dwarf::DW_AT_MIPS_linkage_name,
465                                           dwarf::DW_AT_linkage_name}),
466                          nullptr);
467 }
468 
469 uint64_t DWARFDie::getDeclLine() const {
470   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
471 }
472 
473 std::string
474 DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
475   if (auto FormValue = findRecursively(DW_AT_decl_file))
476     if (auto OptString = FormValue->getAsFile(Kind))
477       return *OptString;
478   return {};
479 }
480 
481 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
482                               uint32_t &CallColumn,
483                               uint32_t &CallDiscriminator) const {
484   CallFile = toUnsigned(find(DW_AT_call_file), 0);
485   CallLine = toUnsigned(find(DW_AT_call_line), 0);
486   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
487   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
488 }
489 
490 std::optional<uint64_t> DWARFDie::getTypeSize(uint64_t PointerSize) {
491   if (auto SizeAttr = find(DW_AT_byte_size))
492     if (std::optional<uint64_t> Size = SizeAttr->getAsUnsignedConstant())
493       return Size;
494 
495   switch (getTag()) {
496   case DW_TAG_pointer_type:
497   case DW_TAG_reference_type:
498   case DW_TAG_rvalue_reference_type:
499     return PointerSize;
500   case DW_TAG_ptr_to_member_type: {
501     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
502       if (BaseType.getTag() == DW_TAG_subroutine_type)
503         return 2 * PointerSize;
504     return PointerSize;
505   }
506   case DW_TAG_const_type:
507   case DW_TAG_immutable_type:
508   case DW_TAG_volatile_type:
509   case DW_TAG_restrict_type:
510   case DW_TAG_typedef: {
511     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
512       return BaseType.getTypeSize(PointerSize);
513     break;
514   }
515   case DW_TAG_array_type: {
516     DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type);
517     if (!BaseType)
518       return std::nullopt;
519     std::optional<uint64_t> BaseSize = BaseType.getTypeSize(PointerSize);
520     if (!BaseSize)
521       return std::nullopt;
522     uint64_t Size = *BaseSize;
523     for (DWARFDie Child : *this) {
524       if (Child.getTag() != DW_TAG_subrange_type)
525         continue;
526 
527       if (auto ElemCountAttr = Child.find(DW_AT_count))
528         if (std::optional<uint64_t> ElemCount =
529                 ElemCountAttr->getAsUnsignedConstant())
530           Size *= *ElemCount;
531       if (auto UpperBoundAttr = Child.find(DW_AT_upper_bound))
532         if (std::optional<int64_t> UpperBound =
533                 UpperBoundAttr->getAsSignedConstant()) {
534           int64_t LowerBound = 0;
535           if (auto LowerBoundAttr = Child.find(DW_AT_lower_bound))
536             LowerBound = LowerBoundAttr->getAsSignedConstant().value_or(0);
537           Size *= *UpperBound - LowerBound + 1;
538         }
539     }
540     return Size;
541   }
542   default:
543     if (DWARFDie BaseType = getAttributeValueAsReferencedDie(DW_AT_type))
544       return BaseType.getTypeSize(PointerSize);
545     break;
546   }
547   return std::nullopt;
548 }
549 
550 /// Helper to dump a DIE with all of its parents, but no siblings.
551 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
552                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
553   if (!Die)
554     return Indent;
555   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
556     return Indent;
557   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
558   Die.dump(OS, Indent, DumpOpts);
559   return Indent + 2;
560 }
561 
562 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
563                     DIDumpOptions DumpOpts) const {
564   if (!isValid())
565     return;
566   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
567   const uint64_t Offset = getOffset();
568   uint64_t offset = Offset;
569   if (DumpOpts.ShowParents) {
570     DIDumpOptions ParentDumpOpts = DumpOpts;
571     ParentDumpOpts.ShowParents = false;
572     ParentDumpOpts.ShowChildren = false;
573     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
574   }
575 
576   if (debug_info_data.isValidOffset(offset)) {
577     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
578     if (DumpOpts.ShowAddresses)
579       WithColor(OS, HighlightColor::Address).get()
580           << format("\n0x%8.8" PRIx64 ": ", Offset);
581 
582     if (abbrCode) {
583       auto AbbrevDecl = getAbbreviationDeclarationPtr();
584       if (AbbrevDecl) {
585         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
586             << formatv("{0}", getTag());
587         if (DumpOpts.Verbose) {
588           OS << format(" [%u] %c", abbrCode,
589                        AbbrevDecl->hasChildren() ? '*' : ' ');
590           if (std::optional<uint32_t> ParentIdx = Die->getParentIdx())
591             OS << format(" (0x%8.8" PRIx64 ")",
592                          U->getDIEAtIndex(*ParentIdx).getOffset());
593         }
594         OS << '\n';
595 
596         // Dump all data in the DIE for the attributes.
597         for (const DWARFAttribute &AttrValue : attributes())
598           dumpAttribute(OS, *this, AttrValue, Indent, DumpOpts);
599 
600         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0) {
601           DWARFDie Child = getFirstChild();
602           DumpOpts.ChildRecurseDepth--;
603           DIDumpOptions ChildDumpOpts = DumpOpts;
604           ChildDumpOpts.ShowParents = false;
605           while (Child) {
606             Child.dump(OS, Indent + 2, ChildDumpOpts);
607             Child = Child.getSibling();
608           }
609         }
610       } else {
611         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
612            << abbrCode << '\n';
613       }
614     } else {
615       OS.indent(Indent) << "NULL\n";
616     }
617   }
618 }
619 
620 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
621 
622 DWARFDie DWARFDie::getParent() const {
623   if (isValid())
624     return U->getParent(Die);
625   return DWARFDie();
626 }
627 
628 DWARFDie DWARFDie::getSibling() const {
629   if (isValid())
630     return U->getSibling(Die);
631   return DWARFDie();
632 }
633 
634 DWARFDie DWARFDie::getPreviousSibling() const {
635   if (isValid())
636     return U->getPreviousSibling(Die);
637   return DWARFDie();
638 }
639 
640 DWARFDie DWARFDie::getFirstChild() const {
641   if (isValid())
642     return U->getFirstChild(Die);
643   return DWARFDie();
644 }
645 
646 DWARFDie DWARFDie::getLastChild() const {
647   if (isValid())
648     return U->getLastChild(Die);
649   return DWARFDie();
650 }
651 
652 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
653   return make_range(attribute_iterator(*this, false),
654                     attribute_iterator(*this, true));
655 }
656 
657 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
658     : Die(D), Index(0) {
659   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
660   assert(AbbrDecl && "Must have abbreviation declaration");
661   if (End) {
662     // This is the end iterator so we set the index to the attribute count.
663     Index = AbbrDecl->getNumAttributes();
664   } else {
665     // This is the begin iterator so we extract the value for this->Index.
666     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
667     updateForIndex(*AbbrDecl, 0);
668   }
669 }
670 
671 void DWARFDie::attribute_iterator::updateForIndex(
672     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
673   Index = I;
674   // AbbrDecl must be valid before calling this function.
675   auto NumAttrs = AbbrDecl.getNumAttributes();
676   if (Index < NumAttrs) {
677     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
678     // Add the previous byte size of any previous attribute value.
679     AttrValue.Offset += AttrValue.ByteSize;
680     uint64_t ParseOffset = AttrValue.Offset;
681     if (AbbrDecl.getAttrIsImplicitConstByIndex(Index))
682       AttrValue.Value = DWARFFormValue::createFromSValue(
683           AbbrDecl.getFormByIndex(Index),
684           AbbrDecl.getAttrImplicitConstValueByIndex(Index));
685     else {
686       auto U = Die.getDwarfUnit();
687       assert(U && "Die must have valid DWARF unit");
688       AttrValue.Value = DWARFFormValue::createFromUnit(
689           AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
690     }
691     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
692   } else {
693     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
694     AttrValue = {};
695   }
696 }
697 
698 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
699   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
700     updateForIndex(*AbbrDecl, Index + 1);
701   return *this;
702 }
703 
704 bool DWARFAttribute::mayHaveLocationList(dwarf::Attribute Attr) {
705   switch(Attr) {
706   case DW_AT_location:
707   case DW_AT_string_length:
708   case DW_AT_return_addr:
709   case DW_AT_data_member_location:
710   case DW_AT_frame_base:
711   case DW_AT_static_link:
712   case DW_AT_segment:
713   case DW_AT_use_location:
714   case DW_AT_vtable_elem_location:
715     return true;
716   default:
717     return false;
718   }
719 }
720 
721 bool DWARFAttribute::mayHaveLocationExpr(dwarf::Attribute Attr) {
722   switch (Attr) {
723   // From the DWARF v5 specification.
724   case DW_AT_location:
725   case DW_AT_byte_size:
726   case DW_AT_bit_offset:
727   case DW_AT_bit_size:
728   case DW_AT_string_length:
729   case DW_AT_lower_bound:
730   case DW_AT_return_addr:
731   case DW_AT_bit_stride:
732   case DW_AT_upper_bound:
733   case DW_AT_count:
734   case DW_AT_data_member_location:
735   case DW_AT_frame_base:
736   case DW_AT_segment:
737   case DW_AT_static_link:
738   case DW_AT_use_location:
739   case DW_AT_vtable_elem_location:
740   case DW_AT_allocated:
741   case DW_AT_associated:
742   case DW_AT_data_location:
743   case DW_AT_byte_stride:
744   case DW_AT_rank:
745   case DW_AT_call_value:
746   case DW_AT_call_origin:
747   case DW_AT_call_target:
748   case DW_AT_call_target_clobbered:
749   case DW_AT_call_data_location:
750   case DW_AT_call_data_value:
751   // Extensions.
752   case DW_AT_GNU_call_site_value:
753   case DW_AT_GNU_call_site_target:
754     return true;
755   default:
756     return false;
757   }
758 }
759 
760 namespace llvm {
761 
762 void dumpTypeQualifiedName(const DWARFDie &DIE, raw_ostream &OS) {
763   DWARFTypePrinter(OS).appendQualifiedName(DIE);
764 }
765 
766 void dumpTypeUnqualifiedName(const DWARFDie &DIE, raw_ostream &OS,
767                              std::string *OriginalFullName) {
768   DWARFTypePrinter(OS).appendUnqualifiedName(DIE, OriginalFullName);
769 }
770 
771 } // namespace llvm
772