xref: /llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp (revision 2e425bf629f80c8f8582c266d25a384e7549198d) 
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/SmallPtrSet.h"
11 #include "llvm/ADT/SmallSet.h"
12 #include "llvm/ADT/StringRef.h"
13 #include "llvm/BinaryFormat/Dwarf.h"
14 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
15 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
16 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
17 #include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
18 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
19 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
20 #include "llvm/DebugInfo/DWARF/DWARFTypePrinter.h"
21 #include "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
22 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
23 #include "llvm/Object/ObjectFile.h"
24 #include "llvm/Support/DataExtractor.h"
25 #include "llvm/Support/Format.h"
26 #include "llvm/Support/FormatVariadic.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 = llvm::countr_zero(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_decl_column ||
151            Attr == DW_AT_call_line || Attr == DW_AT_call_column) {
152     if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
153       OS << *Val;
154     else
155       FormValue.dump(OS, DumpOpts);
156   } else if (Attr == DW_AT_low_pc &&
157              (FormValue.getAsAddress() ==
158               dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
159     if (DumpOpts.Verbose) {
160       FormValue.dump(OS, DumpOpts);
161       OS << " (";
162     }
163     OS << "dead code";
164     if (DumpOpts.Verbose)
165       OS << ')';
166   } else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
167              FormValue.getAsUnsignedConstant()) {
168     if (DumpOpts.ShowAddresses) {
169       // Print the actual address rather than the offset.
170       uint64_t LowPC, HighPC, Index;
171       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
172         DWARFFormValue::dumpAddress(OS, U->getAddressByteSize(), HighPC);
173       else
174         FormValue.dump(OS, DumpOpts);
175     }
176   } else if (DWARFAttribute::mayHaveLocationList(Attr) &&
177              FormValue.isFormClass(DWARFFormValue::FC_SectionOffset))
178     dumpLocationList(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
179                      DumpOpts);
180   else if (FormValue.isFormClass(DWARFFormValue::FC_Exprloc) ||
181            (DWARFAttribute::mayHaveLocationExpr(Attr) &&
182             FormValue.isFormClass(DWARFFormValue::FC_Block)))
183     dumpLocationExpr(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
184                      DumpOpts);
185   else
186     FormValue.dump(OS, DumpOpts);
187 
188   std::string Space = DumpOpts.ShowAddresses ? " " : "";
189 
190   // We have dumped the attribute raw value. For some attributes
191   // having both the raw value and the pretty-printed value is
192   // interesting. These attributes are handled below.
193   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin ||
194       Attr == DW_AT_call_origin) {
195     if (const char *Name =
196             Die.getAttributeValueAsReferencedDie(FormValue).getName(
197                 DINameKind::LinkageName))
198       OS << Space << "\"" << Name << '\"';
199   } else if (Attr == DW_AT_type || Attr == DW_AT_containing_type) {
200     DWARFDie D = resolveReferencedType(Die, FormValue);
201     if (D && !D.isNULL()) {
202       OS << Space << "\"";
203       dumpTypeQualifiedName(D, OS);
204       OS << '"';
205     }
206   } else if (Attr == DW_AT_APPLE_property_attribute) {
207     if (std::optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
208       dumpApplePropertyAttribute(OS, *OptVal);
209   } else if (Attr == DW_AT_ranges) {
210     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
211     // For DW_FORM_rnglistx we need to dump the offset separately, since
212     // we have only dumped the index so far.
213     if (FormValue.getForm() == DW_FORM_rnglistx)
214       if (auto RangeListOffset =
215               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
216         DWARFFormValue FV = DWARFFormValue::createFromUValue(
217             dwarf::DW_FORM_sec_offset, *RangeListOffset);
218         FV.dump(OS, DumpOpts);
219       }
220     if (auto RangesOrError = Die.getAddressRanges())
221       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
222                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
223     else
224       DumpOpts.RecoverableErrorHandler(createStringError(
225           errc::invalid_argument, "decoding address ranges: %s",
226           toString(RangesOrError.takeError()).c_str()));
227   }
228 
229   OS << ")\n";
230 }
231 
232 void DWARFDie::getFullName(raw_string_ostream &OS,
233                            std::string *OriginalFullName) const {
234   const char *NamePtr = getShortName();
235   if (!NamePtr)
236     return;
237   if (getTag() == DW_TAG_GNU_template_parameter_pack)
238     return;
239   dumpTypeUnqualifiedName(*this, OS, OriginalFullName);
240 }
241 
242 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
243 
244 bool DWARFDie::isSubroutineDIE() const {
245   auto Tag = getTag();
246   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
247 }
248 
249 std::optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
250   if (!isValid())
251     return std::nullopt;
252   auto AbbrevDecl = getAbbreviationDeclarationPtr();
253   if (AbbrevDecl)
254     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
255   return std::nullopt;
256 }
257 
258 std::optional<DWARFFormValue>
259 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
260   if (!isValid())
261     return std::nullopt;
262   auto AbbrevDecl = getAbbreviationDeclarationPtr();
263   if (AbbrevDecl) {
264     for (auto Attr : Attrs) {
265       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
266         return Value;
267     }
268   }
269   return std::nullopt;
270 }
271 
272 std::optional<DWARFFormValue>
273 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
274   SmallVector<DWARFDie, 3> Worklist;
275   Worklist.push_back(*this);
276 
277   // Keep track if DIEs already seen to prevent infinite recursion.
278   // Empirically we rarely see a depth of more than 3 when dealing with valid
279   // DWARF. This corresponds to following the DW_AT_abstract_origin and
280   // DW_AT_specification just once.
281   SmallSet<DWARFDie, 3> Seen;
282   Seen.insert(*this);
283 
284   while (!Worklist.empty()) {
285     DWARFDie Die = Worklist.pop_back_val();
286 
287     if (!Die.isValid())
288       continue;
289 
290     if (auto Value = Die.find(Attrs))
291       return Value;
292 
293     for (dwarf::Attribute Attr :
294          {DW_AT_abstract_origin, DW_AT_specification, DW_AT_signature}) {
295       if (auto D = Die.getAttributeValueAsReferencedDie(Attr))
296         if (Seen.insert(D).second)
297           Worklist.push_back(D);
298     }
299   }
300 
301   return std::nullopt;
302 }
303 
304 DWARFDie
305 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
306   if (std::optional<DWARFFormValue> F = find(Attr))
307     return getAttributeValueAsReferencedDie(*F);
308   return DWARFDie();
309 }
310 
311 DWARFDie
312 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
313   DWARFDie Result;
314   if (std::optional<uint64_t> Offset = V.getAsRelativeReference()) {
315     Result = const_cast<DWARFUnit *>(V.getUnit())
316                  ->getDIEForOffset(V.getUnit()->getOffset() + *Offset);
317   } else if (Offset = V.getAsDebugInfoReference(); Offset) {
318     if (DWARFUnit *SpecUnit = U->getUnitVector().getUnitForOffset(*Offset))
319       Result = SpecUnit->getDIEForOffset(*Offset);
320   } else if (std::optional<uint64_t> Sig = V.getAsSignatureReference()) {
321     if (DWARFTypeUnit *TU =
322             U->getContext().getTypeUnitForHash(*Sig, U->isDWOUnit()))
323       Result = TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
324   }
325   return Result;
326 }
327 
328 DWARFDie DWARFDie::resolveTypeUnitReference() const {
329   if (auto Attr = find(DW_AT_signature)) {
330     if (std::optional<uint64_t> Sig = Attr->getAsReferenceUVal()) {
331       if (DWARFTypeUnit *TU =
332               U->getContext().getTypeUnitForHash(*Sig, U->isDWOUnit()))
333         return TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
334     }
335   }
336   return *this;
337 }
338 
339 DWARFDie DWARFDie::resolveReferencedType(dwarf::Attribute Attr) const {
340   return getAttributeValueAsReferencedDie(Attr).resolveTypeUnitReference();
341 }
342 DWARFDie DWARFDie::resolveReferencedType(const DWARFFormValue &V) const {
343   return getAttributeValueAsReferencedDie(V).resolveTypeUnitReference();
344 }
345 
346 std::optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
347   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
348 }
349 
350 std::optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
351   return toSectionOffset(find(DW_AT_loclists_base));
352 }
353 
354 std::optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
355   uint64_t Tombstone = dwarf::computeTombstoneAddress(U->getAddressByteSize());
356   if (LowPC == Tombstone)
357     return std::nullopt;
358   if (auto FormValue = find(DW_AT_high_pc)) {
359     if (auto Address = FormValue->getAsAddress()) {
360       // High PC is an address.
361       return Address;
362     }
363     if (auto Offset = FormValue->getAsUnsignedConstant()) {
364       // High PC is an offset from LowPC.
365       return LowPC + *Offset;
366     }
367   }
368   return std::nullopt;
369 }
370 
371 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
372                                uint64_t &SectionIndex) const {
373   auto F = find(DW_AT_low_pc);
374   auto LowPcAddr = toSectionedAddress(F);
375   if (!LowPcAddr)
376     return false;
377   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
378     LowPC = LowPcAddr->Address;
379     HighPC = *HighPcAddr;
380     SectionIndex = LowPcAddr->SectionIndex;
381     return true;
382   }
383   return false;
384 }
385 
386 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
387   if (isNULL())
388     return DWARFAddressRangesVector();
389   // Single range specified by low/high PC.
390   uint64_t LowPC, HighPC, Index;
391   if (getLowAndHighPC(LowPC, HighPC, Index))
392     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
393 
394   std::optional<DWARFFormValue> Value = find(DW_AT_ranges);
395   if (Value) {
396     if (Value->getForm() == DW_FORM_rnglistx)
397       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
398     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
399   }
400   return DWARFAddressRangesVector();
401 }
402 
403 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
404   auto RangesOrError = getAddressRanges();
405   if (!RangesOrError) {
406     llvm::consumeError(RangesOrError.takeError());
407     return false;
408   }
409 
410   for (const auto &R : RangesOrError.get())
411     if (R.LowPC <= Address && Address < R.HighPC)
412       return true;
413   return false;
414 }
415 
416 std::optional<uint64_t> DWARFDie::getLanguage() const {
417   if (isValid()) {
418     if (std::optional<DWARFFormValue> LV =
419             U->getUnitDIE().find(dwarf::DW_AT_language))
420       return LV->getAsUnsignedConstant();
421   }
422   return std::nullopt;
423 }
424 
425 Expected<DWARFLocationExpressionsVector>
426 DWARFDie::getLocations(dwarf::Attribute Attr) const {
427   std::optional<DWARFFormValue> Location = find(Attr);
428   if (!Location)
429     return createStringError(inconvertibleErrorCode(), "No %s",
430                              dwarf::AttributeString(Attr).data());
431 
432   if (std::optional<uint64_t> Off = Location->getAsSectionOffset()) {
433     uint64_t Offset = *Off;
434 
435     if (Location->getForm() == DW_FORM_loclistx) {
436       if (auto LoclistOffset = U->getLoclistOffset(Offset))
437         Offset = *LoclistOffset;
438       else
439         return createStringError(inconvertibleErrorCode(),
440                                  "Loclist table not found");
441     }
442     return U->findLoclistFromOffset(Offset);
443   }
444 
445   if (std::optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
446     return DWARFLocationExpressionsVector{
447         DWARFLocationExpression{std::nullopt, to_vector<4>(*Expr)}};
448   }
449 
450   return createStringError(
451       inconvertibleErrorCode(), "Unsupported %s encoding: %s",
452       dwarf::AttributeString(Attr).data(),
453       dwarf::FormEncodingString(Location->getForm()).data());
454 }
455 
456 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
457   if (!isSubroutineDIE())
458     return nullptr;
459   return getName(Kind);
460 }
461 
462 const char *DWARFDie::getName(DINameKind Kind) const {
463   if (!isValid() || Kind == DINameKind::None)
464     return nullptr;
465   // Try to get mangled name only if it was asked for.
466   if (Kind == DINameKind::LinkageName) {
467     if (auto Name = getLinkageName())
468       return Name;
469   }
470   return getShortName();
471 }
472 
473 const char *DWARFDie::getShortName() const {
474   if (!isValid())
475     return nullptr;
476 
477   return dwarf::toString(findRecursively(dwarf::DW_AT_name), nullptr);
478 }
479 
480 const char *DWARFDie::getLinkageName() const {
481   if (!isValid())
482     return nullptr;
483 
484   return dwarf::toString(findRecursively({dwarf::DW_AT_MIPS_linkage_name,
485                                           dwarf::DW_AT_linkage_name}),
486                          nullptr);
487 }
488 
489 uint64_t DWARFDie::getDeclLine() const {
490   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
491 }
492 
493 std::string
494 DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
495   if (auto FormValue = findRecursively(DW_AT_decl_file))
496     if (auto OptString = FormValue->getAsFile(Kind))
497       return *OptString;
498   return {};
499 }
500 
501 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
502                               uint32_t &CallColumn,
503                               uint32_t &CallDiscriminator) const {
504   CallFile = toUnsigned(find(DW_AT_call_file), 0);
505   CallLine = toUnsigned(find(DW_AT_call_line), 0);
506   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
507   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
508 }
509 
510 static std::optional<uint64_t>
511 getTypeSizeImpl(DWARFDie Die, uint64_t PointerSize,
512                 SmallPtrSetImpl<const DWARFDebugInfoEntry *> &Visited) {
513   // Cycle detected?
514   if (!Visited.insert(Die.getDebugInfoEntry()).second)
515     return {};
516   if (auto SizeAttr = Die.find(DW_AT_byte_size))
517     if (std::optional<uint64_t> Size = SizeAttr->getAsUnsignedConstant())
518       return Size;
519 
520   switch (Die.getTag()) {
521   case DW_TAG_pointer_type:
522   case DW_TAG_reference_type:
523   case DW_TAG_rvalue_reference_type:
524     return PointerSize;
525   case DW_TAG_ptr_to_member_type: {
526     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
527       if (BaseType.getTag() == DW_TAG_subroutine_type)
528         return 2 * PointerSize;
529     return PointerSize;
530   }
531   case DW_TAG_const_type:
532   case DW_TAG_immutable_type:
533   case DW_TAG_volatile_type:
534   case DW_TAG_restrict_type:
535   case DW_TAG_template_alias:
536   case DW_TAG_typedef: {
537     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
538       return getTypeSizeImpl(BaseType, PointerSize, Visited);
539     break;
540   }
541   case DW_TAG_array_type: {
542     DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type);
543     if (!BaseType)
544       return std::nullopt;
545     std::optional<uint64_t> BaseSize =
546         getTypeSizeImpl(BaseType, PointerSize, Visited);
547     if (!BaseSize)
548       return std::nullopt;
549     uint64_t Size = *BaseSize;
550     for (DWARFDie Child : Die) {
551       if (Child.getTag() != DW_TAG_subrange_type)
552         continue;
553 
554       if (auto ElemCountAttr = Child.find(DW_AT_count))
555         if (std::optional<uint64_t> ElemCount =
556                 ElemCountAttr->getAsUnsignedConstant())
557           Size *= *ElemCount;
558       if (auto UpperBoundAttr = Child.find(DW_AT_upper_bound))
559         if (std::optional<int64_t> UpperBound =
560                 UpperBoundAttr->getAsSignedConstant()) {
561           int64_t LowerBound = 0;
562           if (auto LowerBoundAttr = Child.find(DW_AT_lower_bound))
563             LowerBound = LowerBoundAttr->getAsSignedConstant().value_or(0);
564           Size *= *UpperBound - LowerBound + 1;
565         }
566     }
567     return Size;
568   }
569   default:
570     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
571       return getTypeSizeImpl(BaseType, PointerSize, Visited);
572     break;
573   }
574   return std::nullopt;
575 }
576 
577 std::optional<uint64_t> DWARFDie::getTypeSize(uint64_t PointerSize) {
578   SmallPtrSet<const DWARFDebugInfoEntry *, 4> Visited;
579   return getTypeSizeImpl(*this, PointerSize, Visited);
580 }
581 
582 /// Helper to dump a DIE with all of its parents, but no siblings.
583 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
584                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
585   if (!Die)
586     return Indent;
587   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
588     return Indent;
589   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
590   Die.dump(OS, Indent, DumpOpts);
591   return Indent + 2;
592 }
593 
594 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
595                     DIDumpOptions DumpOpts) const {
596   if (!isValid())
597     return;
598   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
599   const uint64_t Offset = getOffset();
600   uint64_t offset = Offset;
601   if (DumpOpts.ShowParents) {
602     DIDumpOptions ParentDumpOpts = DumpOpts;
603     ParentDumpOpts.ShowParents = false;
604     ParentDumpOpts.ShowChildren = false;
605     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
606   }
607 
608   if (debug_info_data.isValidOffset(offset)) {
609     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
610     if (DumpOpts.ShowAddresses)
611       WithColor(OS, HighlightColor::Address).get()
612           << format("\n0x%8.8" PRIx64 ": ", Offset);
613 
614     if (abbrCode) {
615       auto AbbrevDecl = getAbbreviationDeclarationPtr();
616       if (AbbrevDecl) {
617         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
618             << formatv("{0}", getTag());
619         if (DumpOpts.Verbose) {
620           OS << format(" [%u] %c", abbrCode,
621                        AbbrevDecl->hasChildren() ? '*' : ' ');
622           if (std::optional<uint32_t> ParentIdx = Die->getParentIdx())
623             OS << format(" (0x%8.8" PRIx64 ")",
624                          U->getDIEAtIndex(*ParentIdx).getOffset());
625         }
626         OS << '\n';
627 
628         // Dump all data in the DIE for the attributes.
629         for (const DWARFAttribute &AttrValue : attributes())
630           dumpAttribute(OS, *this, AttrValue, Indent, DumpOpts);
631 
632         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0) {
633           DWARFDie Child = getFirstChild();
634           DumpOpts.ChildRecurseDepth--;
635           DIDumpOptions ChildDumpOpts = DumpOpts;
636           ChildDumpOpts.ShowParents = false;
637           while (Child) {
638             Child.dump(OS, Indent + 2, ChildDumpOpts);
639             Child = Child.getSibling();
640           }
641         }
642       } else {
643         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
644            << abbrCode << '\n';
645       }
646     } else {
647       OS.indent(Indent) << "NULL\n";
648     }
649   }
650 }
651 
652 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
653 
654 DWARFDie DWARFDie::getParent() const {
655   if (isValid())
656     return U->getParent(Die);
657   return DWARFDie();
658 }
659 
660 DWARFDie DWARFDie::getSibling() const {
661   if (isValid())
662     return U->getSibling(Die);
663   return DWARFDie();
664 }
665 
666 DWARFDie DWARFDie::getPreviousSibling() const {
667   if (isValid())
668     return U->getPreviousSibling(Die);
669   return DWARFDie();
670 }
671 
672 DWARFDie DWARFDie::getFirstChild() const {
673   if (isValid())
674     return U->getFirstChild(Die);
675   return DWARFDie();
676 }
677 
678 DWARFDie DWARFDie::getLastChild() const {
679   if (isValid())
680     return U->getLastChild(Die);
681   return DWARFDie();
682 }
683 
684 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
685   return make_range(attribute_iterator(*this, false),
686                     attribute_iterator(*this, true));
687 }
688 
689 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
690     : Die(D), Index(0) {
691   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
692   assert(AbbrDecl && "Must have abbreviation declaration");
693   if (End) {
694     // This is the end iterator so we set the index to the attribute count.
695     Index = AbbrDecl->getNumAttributes();
696   } else {
697     // This is the begin iterator so we extract the value for this->Index.
698     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
699     updateForIndex(*AbbrDecl, 0);
700   }
701 }
702 
703 void DWARFDie::attribute_iterator::updateForIndex(
704     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
705   Index = I;
706   // AbbrDecl must be valid before calling this function.
707   auto NumAttrs = AbbrDecl.getNumAttributes();
708   if (Index < NumAttrs) {
709     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
710     // Add the previous byte size of any previous attribute value.
711     AttrValue.Offset += AttrValue.ByteSize;
712     uint64_t ParseOffset = AttrValue.Offset;
713     if (AbbrDecl.getAttrIsImplicitConstByIndex(Index))
714       AttrValue.Value = DWARFFormValue::createFromSValue(
715           AbbrDecl.getFormByIndex(Index),
716           AbbrDecl.getAttrImplicitConstValueByIndex(Index));
717     else {
718       auto U = Die.getDwarfUnit();
719       assert(U && "Die must have valid DWARF unit");
720       AttrValue.Value = DWARFFormValue::createFromUnit(
721           AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
722     }
723     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
724   } else {
725     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
726     AttrValue = {};
727   }
728 }
729 
730 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
731   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
732     updateForIndex(*AbbrDecl, Index + 1);
733   return *this;
734 }
735 
736 bool DWARFAttribute::mayHaveLocationList(dwarf::Attribute Attr) {
737   switch(Attr) {
738   case DW_AT_location:
739   case DW_AT_string_length:
740   case DW_AT_return_addr:
741   case DW_AT_data_member_location:
742   case DW_AT_frame_base:
743   case DW_AT_static_link:
744   case DW_AT_segment:
745   case DW_AT_use_location:
746   case DW_AT_vtable_elem_location:
747     return true;
748   default:
749     return false;
750   }
751 }
752 
753 bool DWARFAttribute::mayHaveLocationExpr(dwarf::Attribute Attr) {
754   switch (Attr) {
755   // From the DWARF v5 specification.
756   case DW_AT_location:
757   case DW_AT_byte_size:
758   case DW_AT_bit_offset:
759   case DW_AT_bit_size:
760   case DW_AT_string_length:
761   case DW_AT_lower_bound:
762   case DW_AT_return_addr:
763   case DW_AT_bit_stride:
764   case DW_AT_upper_bound:
765   case DW_AT_count:
766   case DW_AT_data_member_location:
767   case DW_AT_frame_base:
768   case DW_AT_segment:
769   case DW_AT_static_link:
770   case DW_AT_use_location:
771   case DW_AT_vtable_elem_location:
772   case DW_AT_allocated:
773   case DW_AT_associated:
774   case DW_AT_data_location:
775   case DW_AT_byte_stride:
776   case DW_AT_rank:
777   case DW_AT_call_value:
778   case DW_AT_call_origin:
779   case DW_AT_call_target:
780   case DW_AT_call_target_clobbered:
781   case DW_AT_call_data_location:
782   case DW_AT_call_data_value:
783   // Extensions.
784   case DW_AT_GNU_call_site_value:
785   case DW_AT_GNU_call_site_target:
786     return true;
787   default:
788     return false;
789   }
790 }
791 
792 namespace llvm {
793 
794 void dumpTypeQualifiedName(const DWARFDie &DIE, raw_ostream &OS) {
795   DWARFTypePrinter<DWARFDie>(OS).appendQualifiedName(DIE);
796 }
797 
798 void dumpTypeUnqualifiedName(const DWARFDie &DIE, raw_ostream &OS,
799                              std::string *OriginalFullName) {
800   DWARFTypePrinter<DWARFDie>(OS).appendUnqualifiedName(DIE, OriginalFullName);
801 }
802 
803 } // namespace llvm
804