1 //===- DWARFAcceleratorTable.cpp ------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
11 
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/BinaryFormat/Dwarf.h"
14 #include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
15 #include "llvm/Support/Compiler.h"
16 #include "llvm/Support/DJB.h"
17 #include "llvm/Support/Format.h"
18 #include "llvm/Support/FormatVariadic.h"
19 #include "llvm/Support/ScopedPrinter.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include <cstddef>
22 #include <cstdint>
23 #include <utility>
24 
25 using namespace llvm;
26 
27 namespace {
28 struct Atom {
29   unsigned Value;
30 };
31 
32 static raw_ostream &operator<<(raw_ostream &OS, const Atom &A) {
33   StringRef Str = dwarf::AtomTypeString(A.Value);
34   if (!Str.empty())
35     return OS << Str;
36   return OS << "DW_ATOM_unknown_" << format("%x", A.Value);
37 }
38 } // namespace
39 
40 static Atom formatAtom(unsigned Atom) { return {Atom}; }
41 
42 DWARFAcceleratorTable::~DWARFAcceleratorTable() = default;
43 
44 llvm::Error AppleAcceleratorTable::extract() {
45   uint32_t Offset = 0;
46 
47   // Check that we can at least read the header.
48   if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength)+4))
49     return make_error<StringError>("Section too small: cannot read header.",
50                                    inconvertibleErrorCode());
51 
52   Hdr.Magic = AccelSection.getU32(&Offset);
53   Hdr.Version = AccelSection.getU16(&Offset);
54   Hdr.HashFunction = AccelSection.getU16(&Offset);
55   Hdr.BucketCount = AccelSection.getU32(&Offset);
56   Hdr.HashCount = AccelSection.getU32(&Offset);
57   Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
58 
59   // Check that we can read all the hashes and offsets from the
60   // section (see SourceLevelDebugging.rst for the structure of the index).
61   // We need to substract one because we're checking for an *offset* which is
62   // equal to the size for an empty table and hence pointer after the section.
63   if (!AccelSection.isValidOffset(sizeof(Hdr) + Hdr.HeaderDataLength +
64                                   Hdr.BucketCount * 4 + Hdr.HashCount * 8 - 1))
65     return make_error<StringError>(
66         "Section too small: cannot read buckets and hashes.",
67         inconvertibleErrorCode());
68 
69   HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
70   uint32_t NumAtoms = AccelSection.getU32(&Offset);
71 
72   for (unsigned i = 0; i < NumAtoms; ++i) {
73     uint16_t AtomType = AccelSection.getU16(&Offset);
74     auto AtomForm = static_cast<dwarf::Form>(AccelSection.getU16(&Offset));
75     HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
76   }
77 
78   IsValid = true;
79   return Error::success();
80 }
81 
82 uint32_t AppleAcceleratorTable::getNumBuckets() { return Hdr.BucketCount; }
83 uint32_t AppleAcceleratorTable::getNumHashes() { return Hdr.HashCount; }
84 uint32_t AppleAcceleratorTable::getSizeHdr() { return sizeof(Hdr); }
85 uint32_t AppleAcceleratorTable::getHeaderDataLength() {
86   return Hdr.HeaderDataLength;
87 }
88 
89 ArrayRef<std::pair<AppleAcceleratorTable::HeaderData::AtomType,
90                    AppleAcceleratorTable::HeaderData::Form>>
91 AppleAcceleratorTable::getAtomsDesc() {
92   return HdrData.Atoms;
93 }
94 
95 bool AppleAcceleratorTable::validateForms() {
96   for (auto Atom : getAtomsDesc()) {
97     DWARFFormValue FormValue(Atom.second);
98     switch (Atom.first) {
99     case dwarf::DW_ATOM_die_offset:
100     case dwarf::DW_ATOM_die_tag:
101     case dwarf::DW_ATOM_type_flags:
102       if ((!FormValue.isFormClass(DWARFFormValue::FC_Constant) &&
103            !FormValue.isFormClass(DWARFFormValue::FC_Flag)) ||
104           FormValue.getForm() == dwarf::DW_FORM_sdata)
105         return false;
106       break;
107     default:
108       break;
109     }
110   }
111   return true;
112 }
113 
114 std::pair<uint32_t, dwarf::Tag>
115 AppleAcceleratorTable::readAtoms(uint32_t &HashDataOffset) {
116   uint32_t DieOffset = dwarf::DW_INVALID_OFFSET;
117   dwarf::Tag DieTag = dwarf::DW_TAG_null;
118   dwarf::FormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
119 
120   for (auto Atom : getAtomsDesc()) {
121     DWARFFormValue FormValue(Atom.second);
122     FormValue.extractValue(AccelSection, &HashDataOffset, FormParams);
123     switch (Atom.first) {
124     case dwarf::DW_ATOM_die_offset:
125       DieOffset = *FormValue.getAsUnsignedConstant();
126       break;
127     case dwarf::DW_ATOM_die_tag:
128       DieTag = (dwarf::Tag)*FormValue.getAsUnsignedConstant();
129       break;
130     default:
131       break;
132     }
133   }
134   return {DieOffset, DieTag};
135 }
136 
137 void AppleAcceleratorTable::Header::dump(ScopedPrinter &W) const {
138   DictScope HeaderScope(W, "Header");
139   W.printHex("Magic", Magic);
140   W.printHex("Version", Version);
141   W.printHex("Hash function", HashFunction);
142   W.printNumber("Bucket count", BucketCount);
143   W.printNumber("Hashes count", HashCount);
144   W.printNumber("HeaderData length", HeaderDataLength);
145 }
146 
147 Optional<uint64_t> AppleAcceleratorTable::HeaderData::extractOffset(
148     Optional<DWARFFormValue> Value) const {
149   if (!Value)
150     return None;
151 
152   switch (Value->getForm()) {
153   case dwarf::DW_FORM_ref1:
154   case dwarf::DW_FORM_ref2:
155   case dwarf::DW_FORM_ref4:
156   case dwarf::DW_FORM_ref8:
157   case dwarf::DW_FORM_ref_udata:
158     return Value->getRawUValue() + DIEOffsetBase;
159   default:
160     return Value->getAsSectionOffset();
161   }
162 }
163 
164 bool AppleAcceleratorTable::dumpName(ScopedPrinter &W,
165                                      SmallVectorImpl<DWARFFormValue> &AtomForms,
166                                      uint32_t *DataOffset) const {
167   dwarf::FormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
168   uint32_t NameOffset = *DataOffset;
169   if (!AccelSection.isValidOffsetForDataOfSize(*DataOffset, 4)) {
170     W.printString("Incorrectly terminated list.");
171     return false;
172   }
173   unsigned StringOffset = AccelSection.getRelocatedValue(4, DataOffset);
174   if (!StringOffset)
175     return false; // End of list
176 
177   DictScope NameScope(W, ("Name@0x" + Twine::utohexstr(NameOffset)).str());
178   W.startLine() << format("String: 0x%08x", StringOffset);
179   W.getOStream() << " \"" << StringSection.getCStr(&StringOffset) << "\"\n";
180 
181   unsigned NumData = AccelSection.getU32(DataOffset);
182   for (unsigned Data = 0; Data < NumData; ++Data) {
183     ListScope DataScope(W, ("Data " + Twine(Data)).str());
184     unsigned i = 0;
185     for (auto &Atom : AtomForms) {
186       W.startLine() << format("Atom[%d]: ", i++);
187       if (Atom.extractValue(AccelSection, DataOffset, FormParams))
188         Atom.dump(W.getOStream());
189       else
190         W.getOStream() << "Error extracting the value";
191       W.getOStream() << "\n";
192     }
193   }
194   return true; // more entries follow
195 }
196 
197 LLVM_DUMP_METHOD void AppleAcceleratorTable::dump(raw_ostream &OS) const {
198   if (!IsValid)
199     return;
200 
201   ScopedPrinter W(OS);
202 
203   Hdr.dump(W);
204 
205   W.printNumber("DIE offset base", HdrData.DIEOffsetBase);
206   W.printNumber("Number of atoms", uint64_t(HdrData.Atoms.size()));
207   SmallVector<DWARFFormValue, 3> AtomForms;
208   {
209     ListScope AtomsScope(W, "Atoms");
210     unsigned i = 0;
211     for (const auto &Atom : HdrData.Atoms) {
212       DictScope AtomScope(W, ("Atom " + Twine(i++)).str());
213       W.startLine() << "Type: " << formatAtom(Atom.first) << '\n';
214       W.startLine() << "Form: " << formatv("{0}", Atom.second) << '\n';
215       AtomForms.push_back(DWARFFormValue(Atom.second));
216     }
217   }
218 
219   // Now go through the actual tables and dump them.
220   uint32_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
221   unsigned HashesBase = Offset + Hdr.BucketCount * 4;
222   unsigned OffsetsBase = HashesBase + Hdr.HashCount * 4;
223 
224   for (unsigned Bucket = 0; Bucket < Hdr.BucketCount; ++Bucket) {
225     unsigned Index = AccelSection.getU32(&Offset);
226 
227     ListScope BucketScope(W, ("Bucket " + Twine(Bucket)).str());
228     if (Index == UINT32_MAX) {
229       W.printString("EMPTY");
230       continue;
231     }
232 
233     for (unsigned HashIdx = Index; HashIdx < Hdr.HashCount; ++HashIdx) {
234       unsigned HashOffset = HashesBase + HashIdx*4;
235       unsigned OffsetsOffset = OffsetsBase + HashIdx*4;
236       uint32_t Hash = AccelSection.getU32(&HashOffset);
237 
238       if (Hash % Hdr.BucketCount != Bucket)
239         break;
240 
241       unsigned DataOffset = AccelSection.getU32(&OffsetsOffset);
242       ListScope HashScope(W, ("Hash 0x" + Twine::utohexstr(Hash)).str());
243       if (!AccelSection.isValidOffset(DataOffset)) {
244         W.printString("Invalid section offset");
245         continue;
246       }
247       while (dumpName(W, AtomForms, &DataOffset))
248         /*empty*/;
249     }
250   }
251 }
252 
253 AppleAcceleratorTable::Entry::Entry(
254     const AppleAcceleratorTable::HeaderData &HdrData)
255     : HdrData(&HdrData) {
256   Values.reserve(HdrData.Atoms.size());
257   for (const auto &Atom : HdrData.Atoms)
258     Values.push_back(DWARFFormValue(Atom.second));
259 }
260 
261 void AppleAcceleratorTable::Entry::extract(
262     const AppleAcceleratorTable &AccelTable, uint32_t *Offset) {
263 
264   dwarf::FormParams FormParams = {AccelTable.Hdr.Version, 0,
265                                   dwarf::DwarfFormat::DWARF32};
266   for (auto &Atom : Values)
267     Atom.extractValue(AccelTable.AccelSection, Offset, FormParams);
268 }
269 
270 Optional<DWARFFormValue>
271 AppleAcceleratorTable::Entry::lookup(HeaderData::AtomType Atom) const {
272   assert(HdrData && "Dereferencing end iterator?");
273   assert(HdrData->Atoms.size() == Values.size());
274   for (const auto &Tuple : zip_first(HdrData->Atoms, Values)) {
275     if (std::get<0>(Tuple).first == Atom)
276       return std::get<1>(Tuple);
277   }
278   return None;
279 }
280 
281 Optional<uint64_t> AppleAcceleratorTable::Entry::getDIESectionOffset() const {
282   return HdrData->extractOffset(lookup(dwarf::DW_ATOM_die_offset));
283 }
284 
285 Optional<uint64_t> AppleAcceleratorTable::Entry::getCUOffset() const {
286   return HdrData->extractOffset(lookup(dwarf::DW_ATOM_cu_offset));
287 }
288 
289 Optional<dwarf::Tag> AppleAcceleratorTable::Entry::getTag() const {
290   Optional<DWARFFormValue> Tag = lookup(dwarf::DW_ATOM_die_tag);
291   if (!Tag)
292     return None;
293   if (Optional<uint64_t> Value = Tag->getAsUnsignedConstant())
294     return dwarf::Tag(*Value);
295   return None;
296 }
297 
298 AppleAcceleratorTable::ValueIterator::ValueIterator(
299     const AppleAcceleratorTable &AccelTable, unsigned Offset)
300     : AccelTable(&AccelTable), Current(AccelTable.HdrData), DataOffset(Offset) {
301   if (!AccelTable.AccelSection.isValidOffsetForDataOfSize(DataOffset, 4))
302     return;
303 
304   // Read the first entry.
305   NumData = AccelTable.AccelSection.getU32(&DataOffset);
306   Next();
307 }
308 
309 void AppleAcceleratorTable::ValueIterator::Next() {
310   assert(NumData > 0 && "attempted to increment iterator past the end");
311   auto &AccelSection = AccelTable->AccelSection;
312   if (Data >= NumData ||
313       !AccelSection.isValidOffsetForDataOfSize(DataOffset, 4)) {
314     NumData = 0;
315     return;
316   }
317   Current.extract(*AccelTable, &DataOffset);
318   ++Data;
319 }
320 
321 iterator_range<AppleAcceleratorTable::ValueIterator>
322 AppleAcceleratorTable::equal_range(StringRef Key) const {
323   if (!IsValid)
324     return make_range(ValueIterator(), ValueIterator());
325 
326   // Find the bucket.
327   unsigned HashValue = djbHash(Key);
328   unsigned Bucket = HashValue % Hdr.BucketCount;
329   unsigned BucketBase = sizeof(Hdr) + Hdr.HeaderDataLength;
330   unsigned HashesBase = BucketBase + Hdr.BucketCount * 4;
331   unsigned OffsetsBase = HashesBase + Hdr.HashCount * 4;
332 
333   unsigned BucketOffset = BucketBase + Bucket * 4;
334   unsigned Index = AccelSection.getU32(&BucketOffset);
335 
336   // Search through all hashes in the bucket.
337   for (unsigned HashIdx = Index; HashIdx < Hdr.HashCount; ++HashIdx) {
338     unsigned HashOffset = HashesBase + HashIdx * 4;
339     unsigned OffsetsOffset = OffsetsBase + HashIdx * 4;
340     uint32_t Hash = AccelSection.getU32(&HashOffset);
341 
342     if (Hash % Hdr.BucketCount != Bucket)
343       // We are already in the next bucket.
344       break;
345 
346     unsigned DataOffset = AccelSection.getU32(&OffsetsOffset);
347     unsigned StringOffset = AccelSection.getRelocatedValue(4, &DataOffset);
348     if (!StringOffset)
349       break;
350 
351     // Finally, compare the key.
352     if (Key == StringSection.getCStr(&StringOffset))
353       return make_range({*this, DataOffset}, ValueIterator());
354   }
355   return make_range(ValueIterator(), ValueIterator());
356 }
357 
358 void DWARFDebugNames::Header::dump(ScopedPrinter &W) const {
359   DictScope HeaderScope(W, "Header");
360   W.printHex("Length", UnitLength);
361   W.printNumber("Version", Version);
362   W.printHex("Padding", Padding);
363   W.printNumber("CU count", CompUnitCount);
364   W.printNumber("Local TU count", LocalTypeUnitCount);
365   W.printNumber("Foreign TU count", ForeignTypeUnitCount);
366   W.printNumber("Bucket count", BucketCount);
367   W.printNumber("Name count", NameCount);
368   W.printHex("Abbreviations table size", AbbrevTableSize);
369   W.startLine() << "Augmentation: '" << AugmentationString << "'\n";
370 }
371 
372 llvm::Error DWARFDebugNames::Header::extract(const DWARFDataExtractor &AS,
373                                              uint32_t *Offset) {
374   // Check that we can read the fixed-size part.
375   if (!AS.isValidOffset(*Offset + sizeof(HeaderPOD) - 1))
376     return make_error<StringError>("Section too small: cannot read header.",
377                                    inconvertibleErrorCode());
378 
379   UnitLength = AS.getU32(Offset);
380   Version = AS.getU16(Offset);
381   Padding = AS.getU16(Offset);
382   CompUnitCount = AS.getU32(Offset);
383   LocalTypeUnitCount = AS.getU32(Offset);
384   ForeignTypeUnitCount = AS.getU32(Offset);
385   BucketCount = AS.getU32(Offset);
386   NameCount = AS.getU32(Offset);
387   AbbrevTableSize = AS.getU32(Offset);
388   AugmentationStringSize = alignTo(AS.getU32(Offset), 4);
389 
390   if (!AS.isValidOffsetForDataOfSize(*Offset, AugmentationStringSize))
391     return make_error<StringError>(
392         "Section too small: cannot read header augmentation.",
393         inconvertibleErrorCode());
394   AugmentationString.resize(AugmentationStringSize);
395   AS.getU8(Offset, reinterpret_cast<uint8_t *>(AugmentationString.data()),
396            AugmentationStringSize);
397   return Error::success();
398 }
399 
400 void DWARFDebugNames::Abbrev::dump(ScopedPrinter &W) const {
401   DictScope AbbrevScope(W, ("Abbreviation 0x" + Twine::utohexstr(Code)).str());
402   W.startLine() << formatv("Tag: {0}\n", Tag);
403 
404   for (const auto &Attr : Attributes)
405     W.startLine() << formatv("{0}: {1}\n", Attr.Index, Attr.Form);
406 }
407 
408 static constexpr DWARFDebugNames::AttributeEncoding sentinelAttrEnc() {
409   return {dwarf::Index(0), dwarf::Form(0)};
410 }
411 
412 static bool isSentinel(const DWARFDebugNames::AttributeEncoding &AE) {
413   return AE == sentinelAttrEnc();
414 }
415 
416 static DWARFDebugNames::Abbrev sentinelAbbrev() {
417   return DWARFDebugNames::Abbrev(0, dwarf::Tag(0), {});
418 }
419 
420 static bool isSentinel(const DWARFDebugNames::Abbrev &Abbr) {
421   return Abbr.Code == 0;
422 }
423 
424 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getEmptyKey() {
425   return sentinelAbbrev();
426 }
427 
428 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getTombstoneKey() {
429   return DWARFDebugNames::Abbrev(~0, dwarf::Tag(0), {});
430 }
431 
432 Expected<DWARFDebugNames::AttributeEncoding>
433 DWARFDebugNames::NameIndex::extractAttributeEncoding(uint32_t *Offset) {
434   if (*Offset >= EntriesBase) {
435     return make_error<StringError>("Incorrectly terminated abbreviation table.",
436                                    inconvertibleErrorCode());
437   }
438 
439   uint32_t Index = Section.AccelSection.getULEB128(Offset);
440   uint32_t Form = Section.AccelSection.getULEB128(Offset);
441   return AttributeEncoding(dwarf::Index(Index), dwarf::Form(Form));
442 }
443 
444 Expected<std::vector<DWARFDebugNames::AttributeEncoding>>
445 DWARFDebugNames::NameIndex::extractAttributeEncodings(uint32_t *Offset) {
446   std::vector<AttributeEncoding> Result;
447   for (;;) {
448     auto AttrEncOr = extractAttributeEncoding(Offset);
449     if (!AttrEncOr)
450       return AttrEncOr.takeError();
451     if (isSentinel(*AttrEncOr))
452       return std::move(Result);
453 
454     Result.emplace_back(*AttrEncOr);
455   }
456 }
457 
458 Expected<DWARFDebugNames::Abbrev>
459 DWARFDebugNames::NameIndex::extractAbbrev(uint32_t *Offset) {
460   if (*Offset >= EntriesBase) {
461     return make_error<StringError>("Incorrectly terminated abbreviation table.",
462                                    inconvertibleErrorCode());
463   }
464 
465   uint32_t Code = Section.AccelSection.getULEB128(Offset);
466   if (Code == 0)
467     return sentinelAbbrev();
468 
469   uint32_t Tag = Section.AccelSection.getULEB128(Offset);
470   auto AttrEncOr = extractAttributeEncodings(Offset);
471   if (!AttrEncOr)
472     return AttrEncOr.takeError();
473   return Abbrev(Code, dwarf::Tag(Tag), std::move(*AttrEncOr));
474 }
475 
476 Error DWARFDebugNames::NameIndex::extract() {
477   const DWARFDataExtractor &AS = Section.AccelSection;
478   uint32_t Offset = Base;
479   if (Error E = Hdr.extract(AS, &Offset))
480     return E;
481 
482   CUsBase = Offset;
483   Offset += Hdr.CompUnitCount * 4;
484   Offset += Hdr.LocalTypeUnitCount * 4;
485   Offset += Hdr.ForeignTypeUnitCount * 8;
486   BucketsBase = Offset;
487   Offset += Hdr.BucketCount * 4;
488   HashesBase = Offset;
489   if (Hdr.BucketCount > 0)
490     Offset += Hdr.NameCount * 4;
491   StringOffsetsBase = Offset;
492   Offset += Hdr.NameCount * 4;
493   EntryOffsetsBase = Offset;
494   Offset += Hdr.NameCount * 4;
495 
496   if (!AS.isValidOffsetForDataOfSize(Offset, Hdr.AbbrevTableSize))
497     return make_error<StringError>(
498         "Section too small: cannot read abbreviations.",
499         inconvertibleErrorCode());
500 
501   EntriesBase = Offset + Hdr.AbbrevTableSize;
502 
503   for (;;) {
504     auto AbbrevOr = extractAbbrev(&Offset);
505     if (!AbbrevOr)
506       return AbbrevOr.takeError();
507     if (isSentinel(*AbbrevOr))
508       return Error::success();
509 
510     if (!Abbrevs.insert(std::move(*AbbrevOr)).second) {
511       return make_error<StringError>("Duplicate abbreviation code.",
512                                      inconvertibleErrorCode());
513     }
514   }
515 }
516 DWARFDebugNames::Entry::Entry(const NameIndex &NameIdx, const Abbrev &Abbr)
517     : NameIdx(&NameIdx), Abbr(&Abbr) {
518   // This merely creates form values. It is up to the caller
519   // (NameIndex::getEntry) to populate them.
520   Values.reserve(Abbr.Attributes.size());
521   for (const auto &Attr : Abbr.Attributes)
522     Values.emplace_back(Attr.Form);
523 }
524 
525 Optional<DWARFFormValue>
526 DWARFDebugNames::Entry::lookup(dwarf::Index Index) const {
527   assert(Abbr->Attributes.size() == Values.size());
528   for (const auto &Tuple : zip_first(Abbr->Attributes, Values)) {
529     if (std::get<0>(Tuple).Index == Index)
530       return std::get<1>(Tuple);
531   }
532   return None;
533 }
534 
535 Optional<uint64_t> DWARFDebugNames::Entry::getDIEUnitOffset() const {
536   if (Optional<DWARFFormValue> Off = lookup(dwarf::DW_IDX_die_offset))
537     return Off->getAsReferenceUVal();
538   return None;
539 }
540 
541 Optional<uint64_t> DWARFDebugNames::Entry::getCUIndex() const {
542   if (Optional<DWARFFormValue> Off = lookup(dwarf::DW_IDX_compile_unit))
543     return Off->getAsUnsignedConstant();
544   // In a per-CU index, the entries without a DW_IDX_compile_unit attribute
545   // implicitly refer to the single CU.
546   if (NameIdx->getCUCount() == 1)
547     return 0;
548   return None;
549 }
550 
551 Optional<uint64_t> DWARFDebugNames::Entry::getCUOffset() const {
552   Optional<uint64_t> Index = getCUIndex();
553   if (!Index || *Index >= NameIdx->getCUCount())
554     return None;
555   return NameIdx->getCUOffset(*Index);
556 }
557 
558 Optional<uint64_t> DWARFDebugNames::Entry::getDIESectionOffset() const {
559   Optional<uint64_t> CUOff = getCUOffset();
560   Optional<uint64_t> DIEOff = getDIEUnitOffset();
561   if (CUOff && DIEOff)
562     return *CUOff + *DIEOff;
563   return None;
564 }
565 
566 void DWARFDebugNames::Entry::dump(ScopedPrinter &W) const {
567   W.printHex("Abbrev", Abbr->Code);
568   W.startLine() << formatv("Tag: {0}\n", Abbr->Tag);
569   assert(Abbr->Attributes.size() == Values.size());
570   for (const auto &Tuple : zip_first(Abbr->Attributes, Values)) {
571     W.startLine() << formatv("{0}: ", std::get<0>(Tuple).Index);
572     std::get<1>(Tuple).dump(W.getOStream());
573     W.getOStream() << '\n';
574   }
575 }
576 
577 char DWARFDebugNames::SentinelError::ID;
578 std::error_code DWARFDebugNames::SentinelError::convertToErrorCode() const {
579   return inconvertibleErrorCode();
580 }
581 
582 uint32_t DWARFDebugNames::NameIndex::getCUOffset(uint32_t CU) const {
583   assert(CU < Hdr.CompUnitCount);
584   uint32_t Offset = CUsBase + 4 * CU;
585   return Section.AccelSection.getRelocatedValue(4, &Offset);
586 }
587 
588 uint32_t DWARFDebugNames::NameIndex::getLocalTUOffset(uint32_t TU) const {
589   assert(TU < Hdr.LocalTypeUnitCount);
590   uint32_t Offset = CUsBase + Hdr.CompUnitCount * 4;
591   return Section.AccelSection.getRelocatedValue(4, &Offset);
592 }
593 
594 uint64_t DWARFDebugNames::NameIndex::getForeignTUSignature(uint32_t TU) const {
595   assert(TU < Hdr.ForeignTypeUnitCount);
596   uint32_t Offset = CUsBase + (Hdr.CompUnitCount + Hdr.LocalTypeUnitCount) * 4;
597   return Section.AccelSection.getU64(&Offset);
598 }
599 
600 Expected<DWARFDebugNames::Entry>
601 DWARFDebugNames::NameIndex::getEntry(uint32_t *Offset) const {
602   const DWARFDataExtractor &AS = Section.AccelSection;
603   if (!AS.isValidOffset(*Offset))
604     return make_error<StringError>("Incorrectly terminated entry list.",
605                                    inconvertibleErrorCode());
606 
607   uint32_t AbbrevCode = AS.getULEB128(Offset);
608   if (AbbrevCode == 0)
609     return make_error<SentinelError>();
610 
611   const auto AbbrevIt = Abbrevs.find_as(AbbrevCode);
612   if (AbbrevIt == Abbrevs.end())
613     return make_error<StringError>("Invalid abbreviation.",
614                                    inconvertibleErrorCode());
615 
616   Entry E(*this, *AbbrevIt);
617 
618   dwarf::FormParams FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
619   for (auto &Value : E.Values) {
620     if (!Value.extractValue(AS, Offset, FormParams))
621       return make_error<StringError>("Error extracting index attribute values.",
622                                      inconvertibleErrorCode());
623   }
624   return std::move(E);
625 }
626 
627 DWARFDebugNames::NameTableEntry
628 DWARFDebugNames::NameIndex::getNameTableEntry(uint32_t Index) const {
629   assert(0 < Index && Index <= Hdr.NameCount);
630   uint32_t StringOffsetOffset = StringOffsetsBase + 4 * (Index - 1);
631   uint32_t EntryOffsetOffset = EntryOffsetsBase + 4 * (Index - 1);
632   const DWARFDataExtractor &AS = Section.AccelSection;
633 
634   uint32_t StringOffset = AS.getRelocatedValue(4, &StringOffsetOffset);
635   uint32_t EntryOffset = AS.getU32(&EntryOffsetOffset);
636   EntryOffset += EntriesBase;
637   return {StringOffset, EntryOffset};
638 }
639 
640 uint32_t
641 DWARFDebugNames::NameIndex::getBucketArrayEntry(uint32_t Bucket) const {
642   assert(Bucket < Hdr.BucketCount);
643   uint32_t BucketOffset = BucketsBase + 4 * Bucket;
644   return Section.AccelSection.getU32(&BucketOffset);
645 }
646 
647 uint32_t DWARFDebugNames::NameIndex::getHashArrayEntry(uint32_t Index) const {
648   assert(0 < Index && Index <= Hdr.NameCount);
649   uint32_t HashOffset = HashesBase + 4 * (Index - 1);
650   return Section.AccelSection.getU32(&HashOffset);
651 }
652 
653 // Returns true if we should continue scanning for entries, false if this is the
654 // last (sentinel) entry). In case of a parsing error we also return false, as
655 // it's not possible to recover this entry list (but the other lists may still
656 // parse OK).
657 bool DWARFDebugNames::NameIndex::dumpEntry(ScopedPrinter &W,
658                                            uint32_t *Offset) const {
659   uint32_t EntryId = *Offset;
660   auto EntryOr = getEntry(Offset);
661   if (!EntryOr) {
662     handleAllErrors(EntryOr.takeError(), [](const SentinelError &) {},
663                     [&W](const ErrorInfoBase &EI) { EI.log(W.startLine()); });
664     return false;
665   }
666 
667   DictScope EntryScope(W, ("Entry @ 0x" + Twine::utohexstr(EntryId)).str());
668   EntryOr->dump(W);
669   return true;
670 }
671 
672 void DWARFDebugNames::NameIndex::dumpName(ScopedPrinter &W, uint32_t Index,
673                                           Optional<uint32_t> Hash) const {
674   const DataExtractor &SS = Section.StringSection;
675   NameTableEntry NTE = getNameTableEntry(Index);
676 
677   DictScope NameScope(W, ("Name " + Twine(Index)).str());
678   if (Hash)
679     W.printHex("Hash", *Hash);
680 
681   W.startLine() << format("String: 0x%08x", NTE.StringOffset);
682   W.getOStream() << " \"" << SS.getCStr(&NTE.StringOffset) << "\"\n";
683 
684   while (dumpEntry(W, &NTE.EntryOffset))
685     /*empty*/;
686 }
687 
688 void DWARFDebugNames::NameIndex::dumpCUs(ScopedPrinter &W) const {
689   ListScope CUScope(W, "Compilation Unit offsets");
690   for (uint32_t CU = 0; CU < Hdr.CompUnitCount; ++CU)
691     W.startLine() << format("CU[%u]: 0x%08x\n", CU, getCUOffset(CU));
692 }
693 
694 void DWARFDebugNames::NameIndex::dumpLocalTUs(ScopedPrinter &W) const {
695   if (Hdr.LocalTypeUnitCount == 0)
696     return;
697 
698   ListScope TUScope(W, "Local Type Unit offsets");
699   for (uint32_t TU = 0; TU < Hdr.LocalTypeUnitCount; ++TU)
700     W.startLine() << format("LocalTU[%u]: 0x%08x\n", TU, getLocalTUOffset(TU));
701 }
702 
703 void DWARFDebugNames::NameIndex::dumpForeignTUs(ScopedPrinter &W) const {
704   if (Hdr.ForeignTypeUnitCount == 0)
705     return;
706 
707   ListScope TUScope(W, "Foreign Type Unit signatures");
708   for (uint32_t TU = 0; TU < Hdr.ForeignTypeUnitCount; ++TU) {
709     W.startLine() << format("ForeignTU[%u]: 0x%016" PRIx64 "\n", TU,
710                             getForeignTUSignature(TU));
711   }
712 }
713 
714 void DWARFDebugNames::NameIndex::dumpAbbreviations(ScopedPrinter &W) const {
715   ListScope AbbrevsScope(W, "Abbreviations");
716   for (const auto &Abbr : Abbrevs)
717     Abbr.dump(W);
718 }
719 
720 void DWARFDebugNames::NameIndex::dumpBucket(ScopedPrinter &W,
721                                             uint32_t Bucket) const {
722   ListScope BucketScope(W, ("Bucket " + Twine(Bucket)).str());
723   uint32_t Index = getBucketArrayEntry(Bucket);
724   if (Index == 0) {
725     W.printString("EMPTY");
726     return;
727   }
728   if (Index > Hdr.NameCount) {
729     W.printString("Name index is invalid");
730     return;
731   }
732 
733   for (; Index <= Hdr.NameCount; ++Index) {
734     uint32_t Hash = getHashArrayEntry(Index);
735     if (Hash % Hdr.BucketCount != Bucket)
736       break;
737 
738     dumpName(W, Index, Hash);
739   }
740 }
741 
742 LLVM_DUMP_METHOD void DWARFDebugNames::NameIndex::dump(ScopedPrinter &W) const {
743   DictScope UnitScope(W, ("Name Index @ 0x" + Twine::utohexstr(Base)).str());
744   Hdr.dump(W);
745   dumpCUs(W);
746   dumpLocalTUs(W);
747   dumpForeignTUs(W);
748   dumpAbbreviations(W);
749 
750   if (Hdr.BucketCount > 0) {
751     for (uint32_t Bucket = 0; Bucket < Hdr.BucketCount; ++Bucket)
752       dumpBucket(W, Bucket);
753     return;
754   }
755 
756   W.startLine() << "Hash table not present\n";
757   for (uint32_t Index = 1; Index <= Hdr.NameCount; ++Index)
758     dumpName(W, Index, None);
759 }
760 
761 llvm::Error DWARFDebugNames::extract() {
762   uint32_t Offset = 0;
763   while (AccelSection.isValidOffset(Offset)) {
764     NameIndex Next(*this, Offset);
765     if (llvm::Error E = Next.extract())
766       return E;
767     Offset = Next.getNextUnitOffset();
768     NameIndices.push_back(std::move(Next));
769   }
770   return Error::success();
771 }
772 
773 LLVM_DUMP_METHOD void DWARFDebugNames::dump(raw_ostream &OS) const {
774   ScopedPrinter W(OS);
775   for (const NameIndex &NI : NameIndices)
776     NI.dump(W);
777 }
778 
779 Optional<uint32_t>
780 DWARFDebugNames::ValueIterator::findEntryOffsetInCurrentIndex() {
781   const Header &Hdr = CurrentIndex->Hdr;
782   if (Hdr.BucketCount == 0) {
783     // No Hash Table, We need to search through all names in the Name Index.
784     for (uint32_t Index = 1; Index <= Hdr.NameCount; ++Index) {
785       NameTableEntry NTE = CurrentIndex->getNameTableEntry(Index);
786       if (CurrentIndex->Section.StringSection.getCStr(&NTE.StringOffset) == Key)
787         return NTE.EntryOffset;
788     }
789     return None;
790   }
791 
792   // The Name Index has a Hash Table, so use that to speed up the search.
793   // Compute the Key Hash, if it has not been done already.
794   if (!Hash)
795     Hash = caseFoldingDjbHash(Key);
796   uint32_t Bucket = *Hash % Hdr.BucketCount;
797   uint32_t Index = CurrentIndex->getBucketArrayEntry(Bucket);
798   if (Index == 0)
799     return None; // Empty bucket
800 
801   for (; Index <= Hdr.NameCount; ++Index) {
802     uint32_t Hash = CurrentIndex->getHashArrayEntry(Index);
803     if (Hash % Hdr.BucketCount != Bucket)
804       return None; // End of bucket
805 
806     NameTableEntry NTE = CurrentIndex->getNameTableEntry(Index);
807     if (CurrentIndex->Section.StringSection.getCStr(&NTE.StringOffset) == Key)
808       return NTE.EntryOffset;
809   }
810   return None;
811 }
812 
813 bool DWARFDebugNames::ValueIterator::getEntryAtCurrentOffset() {
814   auto EntryOr = CurrentIndex->getEntry(&DataOffset);
815   if (!EntryOr) {
816     consumeError(EntryOr.takeError());
817     return false;
818   }
819   CurrentEntry = std::move(*EntryOr);
820   return true;
821 }
822 
823 bool DWARFDebugNames::ValueIterator::findInCurrentIndex() {
824   Optional<uint32_t> Offset = findEntryOffsetInCurrentIndex();
825   if (!Offset)
826     return false;
827   DataOffset = *Offset;
828   return getEntryAtCurrentOffset();
829 }
830 
831 void DWARFDebugNames::ValueIterator::searchFromStartOfCurrentIndex() {
832   for (const NameIndex *End = CurrentIndex->Section.NameIndices.end();
833        CurrentIndex != End; ++CurrentIndex) {
834     if (findInCurrentIndex())
835       return;
836   }
837   setEnd();
838 }
839 
840 void DWARFDebugNames::ValueIterator::next() {
841   assert(CurrentIndex && "Incrementing an end() iterator?");
842 
843   // First try the next entry in the current Index.
844   if (getEntryAtCurrentOffset())
845     return;
846 
847   // Try the next Name Index.
848   ++CurrentIndex;
849   searchFromStartOfCurrentIndex();
850 }
851 
852 DWARFDebugNames::ValueIterator::ValueIterator(const DWARFDebugNames &AccelTable,
853                                               StringRef Key)
854     : CurrentIndex(AccelTable.NameIndices.begin()), Key(Key) {
855   searchFromStartOfCurrentIndex();
856 }
857 
858 iterator_range<DWARFDebugNames::ValueIterator>
859 DWARFDebugNames::equal_range(StringRef Key) const {
860   if (NameIndices.empty())
861     return make_range(ValueIterator(), ValueIterator());
862   return make_range(ValueIterator(*this, Key), ValueIterator());
863 }
864