xref: /freebsd/contrib/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp (revision 9c77fb6aaa366cbabc80ee1b834bcfe4df135491) 
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/DWARFExpressionPrinter.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/DebugInfo/DWARF/LowLevel/DWARFExpression.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/WithColor.h"
29 #include "llvm/Support/raw_ostream.h"
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 = llvm::countr_zero(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   for (const DWARFAddressRange &R : Ranges) {
66     OS << '\n';
67     OS.indent(Indent);
68     R.dump(OS, AddressSize, DumpOpts, &Obj);
69   }
70 }
71 
72 static void dumpLocationList(raw_ostream &OS, const DWARFFormValue &FormValue,
73                              DWARFUnit *U, unsigned Indent,
74                              DIDumpOptions DumpOpts) {
75   assert(FormValue.isFormClass(DWARFFormValue::FC_SectionOffset) &&
76          "bad FORM for location list");
77   DWARFContext &Ctx = U->getContext();
78   uint64_t Offset = *FormValue.getAsSectionOffset();
79 
80   if (FormValue.getForm() == DW_FORM_loclistx) {
81     FormValue.dump(OS, DumpOpts);
82 
83     if (auto LoclistOffset = U->getLoclistOffset(Offset))
84       Offset = *LoclistOffset;
85     else
86       return;
87   }
88   U->getLocationTable().dumpLocationList(
89       &Offset, OS, U->getBaseAddress(), Ctx.getDWARFObj(), U, DumpOpts, Indent);
90 }
91 
92 static void dumpLocationExpr(raw_ostream &OS, const DWARFFormValue &FormValue,
93                              DWARFUnit *U, unsigned Indent,
94                              DIDumpOptions DumpOpts) {
95   assert((FormValue.isFormClass(DWARFFormValue::FC_Block) ||
96           FormValue.isFormClass(DWARFFormValue::FC_Exprloc)) &&
97          "bad FORM for location expression");
98   DWARFContext &Ctx = U->getContext();
99   ArrayRef<uint8_t> Expr = *FormValue.getAsBlock();
100   DataExtractor Data(StringRef((const char *)Expr.data(), Expr.size()),
101                      Ctx.isLittleEndian(), 0);
102   DWARFExpression DE(Data, U->getAddressByteSize(), U->getFormParams().Format);
103   printDwarfExpression(&DE, OS, DumpOpts, U);
104 }
105 
106 static DWARFDie resolveReferencedType(DWARFDie D, DWARFFormValue F) {
107   return D.getAttributeValueAsReferencedDie(F).resolveTypeUnitReference();
108 }
109 
110 static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
111                           const DWARFAttribute &AttrValue, unsigned Indent,
112                           DIDumpOptions DumpOpts) {
113   if (!Die.isValid())
114     return;
115   const char BaseIndent[] = "            ";
116   OS << BaseIndent;
117   OS.indent(Indent + 2);
118   dwarf::Attribute Attr = AttrValue.Attr;
119   WithColor(OS, HighlightColor::Attribute) << formatv("{0}", Attr);
120 
121   dwarf::Form Form = AttrValue.Value.getForm();
122   if (DumpOpts.Verbose || DumpOpts.ShowForm)
123     OS << formatv(" [{0}]", Form);
124 
125   DWARFUnit *U = Die.getDwarfUnit();
126   const DWARFFormValue &FormValue = AttrValue.Value;
127 
128   OS << "\t(";
129 
130   StringRef Name;
131   std::string File;
132   auto Color = HighlightColor::Enumerator;
133   if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
134     Color = HighlightColor::String;
135     if (const auto *LT = U->getContext().getLineTableForUnit(U)) {
136       if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant()) {
137         if (LT->getFileNameByIndex(
138                 *Val, U->getCompilationDir(),
139                 DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
140                 File)) {
141           File = '"' + File + '"';
142           Name = File;
143         }
144       }
145     }
146   } else if (std::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_decl_column ||
152            Attr == DW_AT_call_line || Attr == DW_AT_call_column) {
153     if (std::optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
154       OS << *Val;
155     else
156       FormValue.dump(OS, DumpOpts);
157   } else if (Attr == DW_AT_low_pc &&
158              (FormValue.getAsAddress() ==
159               dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
160     if (DumpOpts.Verbose) {
161       FormValue.dump(OS, DumpOpts);
162       OS << " (";
163     }
164     OS << "dead code";
165     if (DumpOpts.Verbose)
166       OS << ')';
167   } else if (Attr == DW_AT_high_pc && !DumpOpts.ShowForm && !DumpOpts.Verbose &&
168              FormValue.getAsUnsignedConstant()) {
169     if (DumpOpts.ShowAddresses) {
170       // Print the actual address rather than the offset.
171       uint64_t LowPC, HighPC, Index;
172       if (Die.getLowAndHighPC(LowPC, HighPC, Index))
173         DWARFFormValue::dumpAddress(OS, U->getAddressByteSize(), HighPC);
174       else
175         FormValue.dump(OS, DumpOpts);
176     }
177   } else if (DWARFAttribute::mayHaveLocationList(Attr) &&
178              FormValue.isFormClass(DWARFFormValue::FC_SectionOffset))
179     dumpLocationList(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
180                      DumpOpts);
181   else if (FormValue.isFormClass(DWARFFormValue::FC_Exprloc) ||
182            (DWARFAttribute::mayHaveLocationExpr(Attr) &&
183             FormValue.isFormClass(DWARFFormValue::FC_Block)))
184     dumpLocationExpr(OS, FormValue, U, sizeof(BaseIndent) + Indent + 4,
185                      DumpOpts);
186   else
187     FormValue.dump(OS, DumpOpts);
188 
189   std::string Space = DumpOpts.ShowAddresses ? " " : "";
190 
191   // We have dumped the attribute raw value. For some attributes
192   // having both the raw value and the pretty-printed value is
193   // interesting. These attributes are handled below.
194   if (Attr == DW_AT_specification || Attr == DW_AT_abstract_origin ||
195       Attr == DW_AT_call_origin) {
196     if (const char *Name =
197             Die.getAttributeValueAsReferencedDie(FormValue).getName(
198                 DINameKind::LinkageName))
199       OS << Space << "\"" << Name << '\"';
200   } else if (Attr == DW_AT_type || Attr == DW_AT_containing_type) {
201     DWARFDie D = resolveReferencedType(Die, FormValue);
202     if (D && !D.isNULL()) {
203       OS << Space << "\"";
204       dumpTypeQualifiedName(D, OS);
205       OS << '"';
206     }
207   } else if (Attr == DW_AT_APPLE_property_attribute) {
208     if (std::optional<uint64_t> OptVal = FormValue.getAsUnsignedConstant())
209       dumpApplePropertyAttribute(OS, *OptVal);
210   } else if (Attr == DW_AT_ranges) {
211     const DWARFObject &Obj = Die.getDwarfUnit()->getContext().getDWARFObj();
212     // For DW_FORM_rnglistx we need to dump the offset separately, since
213     // we have only dumped the index so far.
214     if (FormValue.getForm() == DW_FORM_rnglistx)
215       if (auto RangeListOffset =
216               U->getRnglistOffset(*FormValue.getAsSectionOffset())) {
217         DWARFFormValue FV = DWARFFormValue::createFromUValue(
218             dwarf::DW_FORM_sec_offset, *RangeListOffset);
219         FV.dump(OS, DumpOpts);
220       }
221     if (auto RangesOrError = Die.getAddressRanges())
222       dumpRanges(Obj, OS, RangesOrError.get(), U->getAddressByteSize(),
223                  sizeof(BaseIndent) + Indent + 4, DumpOpts);
224     else
225       DumpOpts.RecoverableErrorHandler(createStringError(
226           errc::invalid_argument, "decoding address ranges: %s",
227           toString(RangesOrError.takeError()).c_str()));
228   }
229 
230   OS << ")\n";
231 }
232 
233 void DWARFDie::getFullName(raw_string_ostream &OS,
234                            std::string *OriginalFullName) const {
235   const char *NamePtr = getShortName();
236   if (!NamePtr)
237     return;
238   if (getTag() == DW_TAG_GNU_template_parameter_pack)
239     return;
240   dumpTypeUnqualifiedName(*this, OS, OriginalFullName);
241 }
242 
243 bool DWARFDie::isSubprogramDIE() const { return getTag() == DW_TAG_subprogram; }
244 
245 bool DWARFDie::isSubroutineDIE() const {
246   auto Tag = getTag();
247   return Tag == DW_TAG_subprogram || Tag == DW_TAG_inlined_subroutine;
248 }
249 
250 std::optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute Attr) const {
251   if (!isValid())
252     return std::nullopt;
253   auto AbbrevDecl = getAbbreviationDeclarationPtr();
254   if (AbbrevDecl)
255     return AbbrevDecl->getAttributeValue(getOffset(), Attr, *U);
256   return std::nullopt;
257 }
258 
259 std::optional<DWARFFormValue>
260 DWARFDie::find(ArrayRef<dwarf::Attribute> Attrs) const {
261   if (!isValid())
262     return std::nullopt;
263   auto AbbrevDecl = getAbbreviationDeclarationPtr();
264   if (AbbrevDecl) {
265     for (auto Attr : Attrs) {
266       if (auto Value = AbbrevDecl->getAttributeValue(getOffset(), Attr, *U))
267         return Value;
268     }
269   }
270   return std::nullopt;
271 }
272 
273 std::optional<DWARFFormValue>
274 DWARFDie::findRecursively(ArrayRef<dwarf::Attribute> Attrs) const {
275   SmallVector<DWARFDie, 3> Worklist;
276   Worklist.push_back(*this);
277 
278   // Keep track if DIEs already seen to prevent infinite recursion.
279   // Empirically we rarely see a depth of more than 3 when dealing with valid
280   // DWARF. This corresponds to following the DW_AT_abstract_origin and
281   // DW_AT_specification just once.
282   SmallSet<DWARFDie, 3> Seen;
283   Seen.insert(*this);
284 
285   while (!Worklist.empty()) {
286     DWARFDie Die = Worklist.pop_back_val();
287 
288     if (!Die.isValid())
289       continue;
290 
291     if (auto Value = Die.find(Attrs))
292       return Value;
293 
294     for (dwarf::Attribute Attr :
295          {DW_AT_abstract_origin, DW_AT_specification, DW_AT_signature}) {
296       if (auto D = Die.getAttributeValueAsReferencedDie(Attr))
297         if (Seen.insert(D).second)
298           Worklist.push_back(D);
299     }
300   }
301 
302   return std::nullopt;
303 }
304 
305 DWARFDie
306 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
307   if (std::optional<DWARFFormValue> F = find(Attr))
308     return getAttributeValueAsReferencedDie(*F);
309   return DWARFDie();
310 }
311 
312 DWARFDie
313 DWARFDie::getAttributeValueAsReferencedDie(const DWARFFormValue &V) const {
314   DWARFDie Result;
315   if (std::optional<uint64_t> Offset = V.getAsRelativeReference()) {
316     Result = const_cast<DWARFUnit *>(V.getUnit())
317                  ->getDIEForOffset(V.getUnit()->getOffset() + *Offset);
318   } else if (Offset = V.getAsDebugInfoReference(); Offset) {
319     if (DWARFUnit *SpecUnit = U->getUnitVector().getUnitForOffset(*Offset))
320       Result = SpecUnit->getDIEForOffset(*Offset);
321   } else if (std::optional<uint64_t> Sig = V.getAsSignatureReference()) {
322     if (DWARFTypeUnit *TU =
323             U->getContext().getTypeUnitForHash(*Sig, U->isDWOUnit()))
324       Result = TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
325   }
326   return Result;
327 }
328 
329 DWARFDie DWARFDie::resolveTypeUnitReference() const {
330   if (auto Attr = find(DW_AT_signature)) {
331     if (std::optional<uint64_t> Sig = Attr->getAsReferenceUVal()) {
332       if (DWARFTypeUnit *TU =
333               U->getContext().getTypeUnitForHash(*Sig, U->isDWOUnit()))
334         return TU->getDIEForOffset(TU->getTypeOffset() + TU->getOffset());
335     }
336   }
337   return *this;
338 }
339 
340 DWARFDie DWARFDie::resolveReferencedType(dwarf::Attribute Attr) const {
341   return getAttributeValueAsReferencedDie(Attr).resolveTypeUnitReference();
342 }
343 DWARFDie DWARFDie::resolveReferencedType(const DWARFFormValue &V) const {
344   return getAttributeValueAsReferencedDie(V).resolveTypeUnitReference();
345 }
346 
347 std::optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
348   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
349 }
350 
351 std::optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
352   return toSectionOffset(find(DW_AT_loclists_base));
353 }
354 
355 std::optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
356   uint64_t Tombstone = dwarf::computeTombstoneAddress(U->getAddressByteSize());
357   if (LowPC == Tombstone)
358     return std::nullopt;
359   if (auto FormValue = find(DW_AT_high_pc)) {
360     if (auto Address = FormValue->getAsAddress()) {
361       // High PC is an address.
362       return Address;
363     }
364     if (auto Offset = FormValue->getAsUnsignedConstant()) {
365       // High PC is an offset from LowPC.
366       return LowPC + *Offset;
367     }
368   }
369   return std::nullopt;
370 }
371 
372 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC,
373                                uint64_t &SectionIndex) const {
374   auto F = find(DW_AT_low_pc);
375   auto LowPcAddr = toSectionedAddress(F);
376   if (!LowPcAddr)
377     return false;
378   if (auto HighPcAddr = getHighPC(LowPcAddr->Address)) {
379     LowPC = LowPcAddr->Address;
380     HighPC = *HighPcAddr;
381     SectionIndex = LowPcAddr->SectionIndex;
382     return true;
383   }
384   return false;
385 }
386 
387 Expected<DWARFAddressRangesVector> DWARFDie::getAddressRanges() const {
388   if (isNULL())
389     return DWARFAddressRangesVector();
390   // Single range specified by low/high PC.
391   uint64_t LowPC, HighPC, Index;
392   if (getLowAndHighPC(LowPC, HighPC, Index))
393     return DWARFAddressRangesVector{{LowPC, HighPC, Index}};
394 
395   std::optional<DWARFFormValue> Value = find(DW_AT_ranges);
396   if (Value) {
397     if (Value->getForm() == DW_FORM_rnglistx)
398       return U->findRnglistFromIndex(*Value->getAsSectionOffset());
399     return U->findRnglistFromOffset(*Value->getAsSectionOffset());
400   }
401   return DWARFAddressRangesVector();
402 }
403 
404 bool DWARFDie::addressRangeContainsAddress(const uint64_t Address) const {
405   auto RangesOrError = getAddressRanges();
406   if (!RangesOrError) {
407     llvm::consumeError(RangesOrError.takeError());
408     return false;
409   }
410 
411   for (const auto &R : RangesOrError.get())
412     if (R.LowPC <= Address && Address < R.HighPC)
413       return true;
414   return false;
415 }
416 
417 std::optional<uint64_t> DWARFDie::getLanguage() const {
418   if (isValid()) {
419     if (std::optional<DWARFFormValue> LV =
420             U->getUnitDIE().find(dwarf::DW_AT_language))
421       return LV->getAsUnsignedConstant();
422   }
423   return std::nullopt;
424 }
425 
426 Expected<DWARFLocationExpressionsVector>
427 DWARFDie::getLocations(dwarf::Attribute Attr) const {
428   std::optional<DWARFFormValue> Location = find(Attr);
429   if (!Location)
430     return createStringError(inconvertibleErrorCode(), "No %s",
431                              dwarf::AttributeString(Attr).data());
432 
433   if (std::optional<uint64_t> Off = Location->getAsSectionOffset()) {
434     uint64_t Offset = *Off;
435 
436     if (Location->getForm() == DW_FORM_loclistx) {
437       if (auto LoclistOffset = U->getLoclistOffset(Offset))
438         Offset = *LoclistOffset;
439       else
440         return createStringError(inconvertibleErrorCode(),
441                                  "Loclist table not found");
442     }
443     return U->findLoclistFromOffset(Offset);
444   }
445 
446   if (std::optional<ArrayRef<uint8_t>> Expr = Location->getAsBlock()) {
447     return DWARFLocationExpressionsVector{
448         DWARFLocationExpression{std::nullopt, to_vector<4>(*Expr)}};
449   }
450 
451   return createStringError(
452       inconvertibleErrorCode(), "Unsupported %s encoding: %s",
453       dwarf::AttributeString(Attr).data(),
454       dwarf::FormEncodingString(Location->getForm()).data());
455 }
456 
457 const char *DWARFDie::getSubroutineName(DINameKind Kind) const {
458   if (!isSubroutineDIE())
459     return nullptr;
460   return getName(Kind);
461 }
462 
463 const char *DWARFDie::getName(DINameKind Kind) const {
464   if (!isValid() || Kind == DINameKind::None)
465     return nullptr;
466   // Try to get mangled name only if it was asked for.
467   if (Kind == DINameKind::LinkageName) {
468     if (auto Name = getLinkageName())
469       return Name;
470   }
471   return getShortName();
472 }
473 
474 const char *DWARFDie::getShortName() const {
475   if (!isValid())
476     return nullptr;
477 
478   return dwarf::toString(findRecursively(dwarf::DW_AT_name), nullptr);
479 }
480 
481 const char *DWARFDie::getLinkageName() const {
482   if (!isValid())
483     return nullptr;
484 
485   return dwarf::toString(findRecursively({dwarf::DW_AT_MIPS_linkage_name,
486                                           dwarf::DW_AT_linkage_name}),
487                          nullptr);
488 }
489 
490 uint64_t DWARFDie::getDeclLine() const {
491   return toUnsigned(findRecursively(DW_AT_decl_line), 0);
492 }
493 
494 std::string
495 DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
496   if (auto FormValue = findRecursively(DW_AT_decl_file))
497     if (auto OptString = FormValue->getAsFile(Kind))
498       return *OptString;
499   return {};
500 }
501 
502 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
503                               uint32_t &CallColumn,
504                               uint32_t &CallDiscriminator) const {
505   CallFile = toUnsigned(find(DW_AT_call_file), 0);
506   CallLine = toUnsigned(find(DW_AT_call_line), 0);
507   CallColumn = toUnsigned(find(DW_AT_call_column), 0);
508   CallDiscriminator = toUnsigned(find(DW_AT_GNU_discriminator), 0);
509 }
510 
511 static std::optional<uint64_t>
512 getTypeSizeImpl(DWARFDie Die, uint64_t PointerSize,
513                 SmallPtrSetImpl<const DWARFDebugInfoEntry *> &Visited) {
514   // Cycle detected?
515   if (!Visited.insert(Die.getDebugInfoEntry()).second)
516     return {};
517   if (auto SizeAttr = Die.find(DW_AT_byte_size))
518     if (std::optional<uint64_t> Size = SizeAttr->getAsUnsignedConstant())
519       return Size;
520 
521   switch (Die.getTag()) {
522   case DW_TAG_pointer_type:
523   case DW_TAG_reference_type:
524   case DW_TAG_rvalue_reference_type:
525     return PointerSize;
526   case DW_TAG_ptr_to_member_type: {
527     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
528       if (BaseType.getTag() == DW_TAG_subroutine_type)
529         return 2 * PointerSize;
530     return PointerSize;
531   }
532   case DW_TAG_const_type:
533   case DW_TAG_immutable_type:
534   case DW_TAG_volatile_type:
535   case DW_TAG_restrict_type:
536   case DW_TAG_template_alias:
537   case DW_TAG_typedef: {
538     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
539       return getTypeSizeImpl(BaseType, PointerSize, Visited);
540     break;
541   }
542   case DW_TAG_array_type: {
543     DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type);
544     if (!BaseType)
545       return std::nullopt;
546     std::optional<uint64_t> BaseSize =
547         getTypeSizeImpl(BaseType, PointerSize, Visited);
548     if (!BaseSize)
549       return std::nullopt;
550     uint64_t Size = *BaseSize;
551     for (DWARFDie Child : Die) {
552       if (Child.getTag() != DW_TAG_subrange_type)
553         continue;
554 
555       if (auto ElemCountAttr = Child.find(DW_AT_count))
556         if (std::optional<uint64_t> ElemCount =
557                 ElemCountAttr->getAsUnsignedConstant())
558           Size *= *ElemCount;
559       if (auto UpperBoundAttr = Child.find(DW_AT_upper_bound))
560         if (std::optional<int64_t> UpperBound =
561                 UpperBoundAttr->getAsSignedConstant()) {
562           int64_t LowerBound = 0;
563           if (auto LowerBoundAttr = Child.find(DW_AT_lower_bound))
564             LowerBound = LowerBoundAttr->getAsSignedConstant().value_or(0);
565           Size *= *UpperBound - LowerBound + 1;
566         }
567     }
568     return Size;
569   }
570   default:
571     if (DWARFDie BaseType = Die.getAttributeValueAsReferencedDie(DW_AT_type))
572       return getTypeSizeImpl(BaseType, PointerSize, Visited);
573     break;
574   }
575   return std::nullopt;
576 }
577 
578 std::optional<uint64_t> DWARFDie::getTypeSize(uint64_t PointerSize) {
579   SmallPtrSet<const DWARFDebugInfoEntry *, 4> Visited;
580   return getTypeSizeImpl(*this, PointerSize, Visited);
581 }
582 
583 /// Helper to dump a DIE with all of its parents, but no siblings.
584 static unsigned dumpParentChain(DWARFDie Die, raw_ostream &OS, unsigned Indent,
585                                 DIDumpOptions DumpOpts, unsigned Depth = 0) {
586   if (!Die)
587     return Indent;
588   if (DumpOpts.ParentRecurseDepth > 0 && Depth >= DumpOpts.ParentRecurseDepth)
589     return Indent;
590   Indent = dumpParentChain(Die.getParent(), OS, Indent, DumpOpts, Depth + 1);
591   Die.dump(OS, Indent, DumpOpts);
592   return Indent + 2;
593 }
594 
595 void DWARFDie::dump(raw_ostream &OS, unsigned Indent,
596                     DIDumpOptions DumpOpts) const {
597   if (!isValid())
598     return;
599   DWARFDataExtractor debug_info_data = U->getDebugInfoExtractor();
600   const uint64_t Offset = getOffset();
601   uint64_t offset = Offset;
602   if (DumpOpts.ShowParents) {
603     DIDumpOptions ParentDumpOpts = DumpOpts;
604     ParentDumpOpts.ShowParents = false;
605     ParentDumpOpts.ShowChildren = false;
606     Indent = dumpParentChain(getParent(), OS, Indent, ParentDumpOpts);
607   }
608 
609   if (debug_info_data.isValidOffset(offset)) {
610     uint32_t abbrCode = debug_info_data.getULEB128(&offset);
611     if (DumpOpts.ShowAddresses)
612       WithColor(OS, HighlightColor::Address).get()
613           << format("\n0x%8.8" PRIx64 ": ", Offset);
614 
615     if (abbrCode) {
616       auto AbbrevDecl = getAbbreviationDeclarationPtr();
617       if (AbbrevDecl) {
618         WithColor(OS, HighlightColor::Tag).get().indent(Indent)
619             << formatv("{0}", getTag());
620         if (DumpOpts.Verbose) {
621           OS << format(" [%u] %c", abbrCode,
622                        AbbrevDecl->hasChildren() ? '*' : ' ');
623           if (std::optional<uint32_t> ParentIdx = Die->getParentIdx())
624             OS << format(" (0x%8.8" PRIx64 ")",
625                          U->getDIEAtIndex(*ParentIdx).getOffset());
626         }
627         OS << '\n';
628 
629         // Dump all data in the DIE for the attributes.
630         for (const DWARFAttribute &AttrValue : attributes())
631           dumpAttribute(OS, *this, AttrValue, Indent, DumpOpts);
632 
633         if (DumpOpts.ShowChildren && DumpOpts.ChildRecurseDepth > 0) {
634           DWARFDie Child = getFirstChild();
635           DumpOpts.ChildRecurseDepth--;
636           DIDumpOptions ChildDumpOpts = DumpOpts;
637           ChildDumpOpts.ShowParents = false;
638           while (Child) {
639             Child.dump(OS, Indent + 2, ChildDumpOpts);
640             Child = Child.getSibling();
641           }
642         }
643       } else {
644         OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
645            << abbrCode << '\n';
646       }
647     } else {
648       OS.indent(Indent) << "NULL\n";
649     }
650   }
651 }
652 
653 LLVM_DUMP_METHOD void DWARFDie::dump() const { dump(llvm::errs(), 0); }
654 
655 DWARFDie DWARFDie::getParent() const {
656   if (isValid())
657     return U->getParent(Die);
658   return DWARFDie();
659 }
660 
661 DWARFDie DWARFDie::getSibling() const {
662   if (isValid())
663     return U->getSibling(Die);
664   return DWARFDie();
665 }
666 
667 DWARFDie DWARFDie::getPreviousSibling() const {
668   if (isValid())
669     return U->getPreviousSibling(Die);
670   return DWARFDie();
671 }
672 
673 DWARFDie DWARFDie::getFirstChild() const {
674   if (isValid())
675     return U->getFirstChild(Die);
676   return DWARFDie();
677 }
678 
679 DWARFDie DWARFDie::getLastChild() const {
680   if (isValid())
681     return U->getLastChild(Die);
682   return DWARFDie();
683 }
684 
685 iterator_range<DWARFDie::attribute_iterator> DWARFDie::attributes() const {
686   return make_range(attribute_iterator(*this, false),
687                     attribute_iterator(*this, true));
688 }
689 
690 DWARFDie::attribute_iterator::attribute_iterator(DWARFDie D, bool End)
691     : Die(D), Index(0) {
692   auto AbbrDecl = Die.getAbbreviationDeclarationPtr();
693   assert(AbbrDecl && "Must have abbreviation declaration");
694   if (End) {
695     // This is the end iterator so we set the index to the attribute count.
696     Index = AbbrDecl->getNumAttributes();
697   } else {
698     // This is the begin iterator so we extract the value for this->Index.
699     AttrValue.Offset = D.getOffset() + AbbrDecl->getCodeByteSize();
700     updateForIndex(*AbbrDecl, 0);
701   }
702 }
703 
704 void DWARFDie::attribute_iterator::updateForIndex(
705     const DWARFAbbreviationDeclaration &AbbrDecl, uint32_t I) {
706   Index = I;
707   // AbbrDecl must be valid before calling this function.
708   auto NumAttrs = AbbrDecl.getNumAttributes();
709   if (Index < NumAttrs) {
710     AttrValue.Attr = AbbrDecl.getAttrByIndex(Index);
711     // Add the previous byte size of any previous attribute value.
712     AttrValue.Offset += AttrValue.ByteSize;
713     uint64_t ParseOffset = AttrValue.Offset;
714     if (AbbrDecl.getAttrIsImplicitConstByIndex(Index))
715       AttrValue.Value = DWARFFormValue::createFromSValue(
716           AbbrDecl.getFormByIndex(Index),
717           AbbrDecl.getAttrImplicitConstValueByIndex(Index));
718     else {
719       auto U = Die.getDwarfUnit();
720       assert(U && "Die must have valid DWARF unit");
721       AttrValue.Value = DWARFFormValue::createFromUnit(
722           AbbrDecl.getFormByIndex(Index), U, &ParseOffset);
723     }
724     AttrValue.ByteSize = ParseOffset - AttrValue.Offset;
725   } else {
726     assert(Index == NumAttrs && "Indexes should be [0, NumAttrs) only");
727     AttrValue = {};
728   }
729 }
730 
731 DWARFDie::attribute_iterator &DWARFDie::attribute_iterator::operator++() {
732   if (auto AbbrDecl = Die.getAbbreviationDeclarationPtr())
733     updateForIndex(*AbbrDecl, Index + 1);
734   return *this;
735 }
736 
737 bool DWARFAttribute::mayHaveLocationList(dwarf::Attribute Attr) {
738   switch(Attr) {
739   case DW_AT_location:
740   case DW_AT_string_length:
741   case DW_AT_return_addr:
742   case DW_AT_data_member_location:
743   case DW_AT_frame_base:
744   case DW_AT_static_link:
745   case DW_AT_segment:
746   case DW_AT_use_location:
747   case DW_AT_vtable_elem_location:
748     return true;
749   default:
750     return false;
751   }
752 }
753 
754 bool DWARFAttribute::mayHaveLocationExpr(dwarf::Attribute Attr) {
755   switch (Attr) {
756   // From the DWARF v5 specification.
757   case DW_AT_location:
758   case DW_AT_byte_size:
759   case DW_AT_bit_offset:
760   case DW_AT_bit_size:
761   case DW_AT_string_length:
762   case DW_AT_lower_bound:
763   case DW_AT_return_addr:
764   case DW_AT_bit_stride:
765   case DW_AT_upper_bound:
766   case DW_AT_count:
767   case DW_AT_data_member_location:
768   case DW_AT_frame_base:
769   case DW_AT_segment:
770   case DW_AT_static_link:
771   case DW_AT_use_location:
772   case DW_AT_vtable_elem_location:
773   case DW_AT_allocated:
774   case DW_AT_associated:
775   case DW_AT_data_location:
776   case DW_AT_byte_stride:
777   case DW_AT_rank:
778   case DW_AT_call_value:
779   case DW_AT_call_origin:
780   case DW_AT_call_target:
781   case DW_AT_call_target_clobbered:
782   case DW_AT_call_data_location:
783   case DW_AT_call_data_value:
784   // Extensions.
785   case DW_AT_GNU_call_site_value:
786   case DW_AT_GNU_call_site_target:
787     return true;
788   default:
789     return false;
790   }
791 }
792 
793 namespace llvm {
794 
795 void dumpTypeQualifiedName(const DWARFDie &DIE, raw_ostream &OS) {
796   DWARFTypePrinter<DWARFDie>(OS).appendQualifiedName(DIE);
797 }
798 
799 void dumpTypeUnqualifiedName(const DWARFDie &DIE, raw_ostream &OS,
800                              std::string *OriginalFullName) {
801   DWARFTypePrinter<DWARFDie>(OS).appendUnqualifiedName(DIE, OriginalFullName);
802 }
803 
804 } // namespace llvm
805