xref: /freebsd/contrib/llvm-project/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583) 
1 //===- DWARFAcceleratorTable.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/DWARFAcceleratorTable.h"
10 
11 #include "llvm/ADT/SmallVector.h"
12 #include "llvm/BinaryFormat/Dwarf.h"
13 #include "llvm/Support/Compiler.h"
14 #include "llvm/Support/DJB.h"
15 #include "llvm/Support/Errc.h"
16 #include "llvm/Support/Format.h"
17 #include "llvm/Support/FormatVariadic.h"
18 #include "llvm/Support/ScopedPrinter.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include <cstddef>
21 #include <cstdint>
22 #include <utility>
23 
24 using namespace llvm;
25 
26 namespace {
27 struct Atom {
28   unsigned Value;
29 };
30 
operator <<(raw_ostream & OS,const Atom & A)31 static raw_ostream &operator<<(raw_ostream &OS, const Atom &A) {
32   StringRef Str = dwarf::AtomTypeString(A.Value);
33   if (!Str.empty())
34     return OS << Str;
35   return OS << "DW_ATOM_unknown_" << format("%x", A.Value);
36 }
37 } // namespace
38 
formatAtom(unsigned Atom)39 static Atom formatAtom(unsigned Atom) { return {Atom}; }
40 
41 DWARFAcceleratorTable::~DWARFAcceleratorTable() = default;
42 
extract()43 Error AppleAcceleratorTable::extract() {
44   uint64_t Offset = 0;
45 
46   // Check that we can at least read the header.
47   if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength) + 4))
48     return createStringError(errc::illegal_byte_sequence,
49                              "Section too small: cannot read header.");
50 
51   Hdr.Magic = AccelSection.getU32(&Offset);
52   Hdr.Version = AccelSection.getU16(&Offset);
53   Hdr.HashFunction = AccelSection.getU16(&Offset);
54   Hdr.BucketCount = AccelSection.getU32(&Offset);
55   Hdr.HashCount = AccelSection.getU32(&Offset);
56   Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
57   FormParams = {Hdr.Version, 0, dwarf::DwarfFormat::DWARF32};
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   if (!AccelSection.isValidOffset(getIthBucketBase(Hdr.BucketCount - 1)))
62     return createStringError(
63         errc::illegal_byte_sequence,
64         "Section too small: cannot read buckets and hashes.");
65 
66   HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
67   uint32_t NumAtoms = AccelSection.getU32(&Offset);
68 
69   HashDataEntryLength = 0;
70   auto MakeUnsupportedFormError = [](dwarf::Form Form) {
71     return createStringError(errc::not_supported,
72                              "Unsupported form:" +
73                                  dwarf::FormEncodingString(Form));
74   };
75 
76   for (unsigned i = 0; i < NumAtoms; ++i) {
77     uint16_t AtomType = AccelSection.getU16(&Offset);
78     auto AtomForm = static_cast<dwarf::Form>(AccelSection.getU16(&Offset));
79     HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
80 
81     std::optional<uint8_t> FormSize =
82         dwarf::getFixedFormByteSize(AtomForm, FormParams);
83     if (!FormSize)
84       return MakeUnsupportedFormError(AtomForm);
85     HashDataEntryLength += *FormSize;
86   }
87 
88   IsValid = true;
89   return Error::success();
90 }
91 
getNumBuckets() const92 uint32_t AppleAcceleratorTable::getNumBuckets() const {
93   return Hdr.BucketCount;
94 }
getNumHashes() const95 uint32_t AppleAcceleratorTable::getNumHashes() const { return Hdr.HashCount; }
getSizeHdr() const96 uint32_t AppleAcceleratorTable::getSizeHdr() const { return sizeof(Hdr); }
getHeaderDataLength() const97 uint32_t AppleAcceleratorTable::getHeaderDataLength() const {
98   return Hdr.HeaderDataLength;
99 }
100 
101 ArrayRef<std::pair<AppleAcceleratorTable::HeaderData::AtomType,
102                    AppleAcceleratorTable::HeaderData::Form>>
getAtomsDesc()103 AppleAcceleratorTable::getAtomsDesc() {
104   return HdrData.Atoms;
105 }
106 
validateForms()107 bool AppleAcceleratorTable::validateForms() {
108   for (auto Atom : getAtomsDesc()) {
109     DWARFFormValue FormValue(Atom.second);
110     switch (Atom.first) {
111     case dwarf::DW_ATOM_die_offset:
112     case dwarf::DW_ATOM_die_tag:
113     case dwarf::DW_ATOM_type_flags:
114       if ((!FormValue.isFormClass(DWARFFormValue::FC_Constant) &&
115            !FormValue.isFormClass(DWARFFormValue::FC_Flag)) ||
116           FormValue.getForm() == dwarf::DW_FORM_sdata)
117         return false;
118       break;
119     default:
120       break;
121     }
122   }
123   return true;
124 }
125 
126 std::pair<uint64_t, dwarf::Tag>
readAtoms(uint64_t * HashDataOffset)127 AppleAcceleratorTable::readAtoms(uint64_t *HashDataOffset) {
128   uint64_t DieOffset = dwarf::DW_INVALID_OFFSET;
129   dwarf::Tag DieTag = dwarf::DW_TAG_null;
130 
131   for (auto Atom : getAtomsDesc()) {
132     DWARFFormValue FormValue(Atom.second);
133     FormValue.extractValue(AccelSection, HashDataOffset, FormParams);
134     switch (Atom.first) {
135     case dwarf::DW_ATOM_die_offset:
136       DieOffset = *FormValue.getAsUnsignedConstant();
137       break;
138     case dwarf::DW_ATOM_die_tag:
139       DieTag = (dwarf::Tag)*FormValue.getAsUnsignedConstant();
140       break;
141     default:
142       break;
143     }
144   }
145   return {DieOffset, DieTag};
146 }
147 
dump(ScopedPrinter & W) const148 void AppleAcceleratorTable::Header::dump(ScopedPrinter &W) const {
149   DictScope HeaderScope(W, "Header");
150   W.printHex("Magic", Magic);
151   W.printHex("Version", Version);
152   W.printHex("Hash function", HashFunction);
153   W.printNumber("Bucket count", BucketCount);
154   W.printNumber("Hashes count", HashCount);
155   W.printNumber("HeaderData length", HeaderDataLength);
156 }
157 
extractOffset(std::optional<DWARFFormValue> Value) const158 std::optional<uint64_t> AppleAcceleratorTable::HeaderData::extractOffset(
159     std::optional<DWARFFormValue> Value) const {
160   if (!Value)
161     return std::nullopt;
162 
163   switch (Value->getForm()) {
164   case dwarf::DW_FORM_ref1:
165   case dwarf::DW_FORM_ref2:
166   case dwarf::DW_FORM_ref4:
167   case dwarf::DW_FORM_ref8:
168   case dwarf::DW_FORM_ref_udata:
169     return Value->getRawUValue() + DIEOffsetBase;
170   default:
171     return Value->getAsSectionOffset();
172   }
173 }
174 
dumpName(ScopedPrinter & W,SmallVectorImpl<DWARFFormValue> & AtomForms,uint64_t * DataOffset) const175 bool AppleAcceleratorTable::dumpName(ScopedPrinter &W,
176                                      SmallVectorImpl<DWARFFormValue> &AtomForms,
177                                      uint64_t *DataOffset) const {
178   uint64_t NameOffset = *DataOffset;
179   if (!AccelSection.isValidOffsetForDataOfSize(*DataOffset, 4)) {
180     W.printString("Incorrectly terminated list.");
181     return false;
182   }
183   uint64_t StringOffset = AccelSection.getRelocatedValue(4, DataOffset);
184   if (!StringOffset)
185     return false; // End of list
186 
187   DictScope NameScope(W, ("Name@0x" + Twine::utohexstr(NameOffset)).str());
188   W.startLine() << format("String: 0x%08" PRIx64, StringOffset);
189   W.getOStream() << " \"" << StringSection.getCStr(&StringOffset) << "\"\n";
190 
191   unsigned NumData = AccelSection.getU32(DataOffset);
192   for (unsigned Data = 0; Data < NumData; ++Data) {
193     ListScope DataScope(W, ("Data " + Twine(Data)).str());
194     unsigned i = 0;
195     for (auto &Atom : AtomForms) {
196       W.startLine() << format("Atom[%d]: ", i);
197       if (Atom.extractValue(AccelSection, DataOffset, FormParams)) {
198         Atom.dump(W.getOStream());
199         if (std::optional<uint64_t> Val = Atom.getAsUnsignedConstant()) {
200           StringRef Str = dwarf::AtomValueString(HdrData.Atoms[i].first, *Val);
201           if (!Str.empty())
202             W.getOStream() << " (" << Str << ")";
203         }
204       } else
205         W.getOStream() << "Error extracting the value";
206       W.getOStream() << "\n";
207       i++;
208     }
209   }
210   return true; // more entries follow
211 }
212 
dump(raw_ostream & OS) const213 LLVM_DUMP_METHOD void AppleAcceleratorTable::dump(raw_ostream &OS) const {
214   if (!IsValid)
215     return;
216 
217   ScopedPrinter W(OS);
218 
219   Hdr.dump(W);
220 
221   W.printNumber("DIE offset base", HdrData.DIEOffsetBase);
222   W.printNumber("Number of atoms", uint64_t(HdrData.Atoms.size()));
223   W.printNumber("Size of each hash data entry", getHashDataEntryLength());
224   SmallVector<DWARFFormValue, 3> AtomForms;
225   {
226     ListScope AtomsScope(W, "Atoms");
227     unsigned i = 0;
228     for (const auto &Atom : HdrData.Atoms) {
229       DictScope AtomScope(W, ("Atom " + Twine(i++)).str());
230       W.startLine() << "Type: " << formatAtom(Atom.first) << '\n';
231       W.startLine() << "Form: " << formatv("{0}", Atom.second) << '\n';
232       AtomForms.push_back(DWARFFormValue(Atom.second));
233     }
234   }
235 
236   // Now go through the actual tables and dump them.
237   uint64_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
238   uint64_t HashesBase = Offset + Hdr.BucketCount * 4;
239   uint64_t OffsetsBase = HashesBase + Hdr.HashCount * 4;
240 
241   for (unsigned Bucket = 0; Bucket < Hdr.BucketCount; ++Bucket) {
242     unsigned Index = AccelSection.getU32(&Offset);
243 
244     ListScope BucketScope(W, ("Bucket " + Twine(Bucket)).str());
245     if (Index == UINT32_MAX) {
246       W.printString("EMPTY");
247       continue;
248     }
249 
250     for (unsigned HashIdx = Index; HashIdx < Hdr.HashCount; ++HashIdx) {
251       uint64_t HashOffset = HashesBase + HashIdx*4;
252       uint64_t OffsetsOffset = OffsetsBase + HashIdx*4;
253       uint32_t Hash = AccelSection.getU32(&HashOffset);
254 
255       if (Hash % Hdr.BucketCount != Bucket)
256         break;
257 
258       uint64_t DataOffset = AccelSection.getU32(&OffsetsOffset);
259       ListScope HashScope(W, ("Hash 0x" + Twine::utohexstr(Hash)).str());
260       if (!AccelSection.isValidOffset(DataOffset)) {
261         W.printString("Invalid section offset");
262         continue;
263       }
264       while (dumpName(W, AtomForms, &DataOffset))
265         /*empty*/;
266     }
267   }
268 }
269 
Entry(const AppleAcceleratorTable & Table)270 AppleAcceleratorTable::Entry::Entry(const AppleAcceleratorTable &Table)
271     : Table(Table) {
272   Values.reserve(Table.HdrData.Atoms.size());
273   for (const auto &Atom : Table.HdrData.Atoms)
274     Values.push_back(DWARFFormValue(Atom.second));
275 }
276 
extract(uint64_t * Offset)277 void AppleAcceleratorTable::Entry::extract(uint64_t *Offset) {
278   for (auto &FormValue : Values)
279     FormValue.extractValue(Table.AccelSection, Offset, Table.FormParams);
280 }
281 
282 std::optional<DWARFFormValue>
lookup(HeaderData::AtomType AtomToFind) const283 AppleAcceleratorTable::Entry::lookup(HeaderData::AtomType AtomToFind) const {
284   for (auto [Atom, FormValue] : zip_equal(Table.HdrData.Atoms, Values))
285     if (Atom.first == AtomToFind)
286       return FormValue;
287   return std::nullopt;
288 }
289 
290 std::optional<uint64_t>
getDIESectionOffset() const291 AppleAcceleratorTable::Entry::getDIESectionOffset() const {
292   return Table.HdrData.extractOffset(lookup(dwarf::DW_ATOM_die_offset));
293 }
294 
getCUOffset() const295 std::optional<uint64_t> AppleAcceleratorTable::Entry::getCUOffset() const {
296   return Table.HdrData.extractOffset(lookup(dwarf::DW_ATOM_cu_offset));
297 }
298 
getTag() const299 std::optional<dwarf::Tag> AppleAcceleratorTable::Entry::getTag() const {
300   std::optional<DWARFFormValue> Tag = lookup(dwarf::DW_ATOM_die_tag);
301   if (!Tag)
302     return std::nullopt;
303   if (std::optional<uint64_t> Value = Tag->getAsUnsignedConstant())
304     return dwarf::Tag(*Value);
305   return std::nullopt;
306 }
307 
SameNameIterator(const AppleAcceleratorTable & AccelTable,uint64_t DataOffset)308 AppleAcceleratorTable::SameNameIterator::SameNameIterator(
309     const AppleAcceleratorTable &AccelTable, uint64_t DataOffset)
310     : Current(AccelTable), Offset(DataOffset) {}
311 
prepareNextEntryOrEnd()312 void AppleAcceleratorTable::Iterator::prepareNextEntryOrEnd() {
313   if (NumEntriesToCome == 0)
314     prepareNextStringOrEnd();
315   if (isEnd())
316     return;
317   uint64_t OffsetCopy = Offset;
318   Current.BaseEntry.extract(&OffsetCopy);
319   NumEntriesToCome--;
320   Offset += getTable().getHashDataEntryLength();
321 }
322 
prepareNextStringOrEnd()323 void AppleAcceleratorTable::Iterator::prepareNextStringOrEnd() {
324   std::optional<uint32_t> StrOffset = getTable().readStringOffsetAt(Offset);
325   if (!StrOffset)
326     return setToEnd();
327 
328   // A zero denotes the end of the collision list. Read the next string
329   // again.
330   if (*StrOffset == 0)
331     return prepareNextStringOrEnd();
332   Current.StrOffset = *StrOffset;
333 
334   std::optional<uint32_t> MaybeNumEntries = getTable().readU32FromAccel(Offset);
335   if (!MaybeNumEntries || *MaybeNumEntries == 0)
336     return setToEnd();
337   NumEntriesToCome = *MaybeNumEntries;
338 }
339 
Iterator(const AppleAcceleratorTable & Table,bool SetEnd)340 AppleAcceleratorTable::Iterator::Iterator(const AppleAcceleratorTable &Table,
341                                           bool SetEnd)
342     : Current(Table), Offset(Table.getEntriesBase()), NumEntriesToCome(0) {
343   if (SetEnd)
344     setToEnd();
345   else
346     prepareNextEntryOrEnd();
347 }
348 
349 iterator_range<AppleAcceleratorTable::SameNameIterator>
equal_range(StringRef Key) const350 AppleAcceleratorTable::equal_range(StringRef Key) const {
351   const auto EmptyRange =
352       make_range(SameNameIterator(*this, 0), SameNameIterator(*this, 0));
353   if (!IsValid)
354     return EmptyRange;
355 
356   // Find the bucket.
357   uint32_t SearchHash = djbHash(Key);
358   uint32_t BucketIdx = hashToBucketIdx(SearchHash);
359   std::optional<uint32_t> HashIdx = idxOfHashInBucket(SearchHash, BucketIdx);
360   if (!HashIdx)
361     return EmptyRange;
362 
363   std::optional<uint64_t> MaybeDataOffset = readIthOffset(*HashIdx);
364   if (!MaybeDataOffset)
365     return EmptyRange;
366 
367   uint64_t DataOffset = *MaybeDataOffset;
368   if (DataOffset >= AccelSection.size())
369     return EmptyRange;
370 
371   std::optional<uint32_t> StrOffset = readStringOffsetAt(DataOffset);
372   // Valid input and still have strings in this hash.
373   while (StrOffset && *StrOffset) {
374     std::optional<StringRef> MaybeStr = readStringFromStrSection(*StrOffset);
375     std::optional<uint32_t> NumEntries = this->readU32FromAccel(DataOffset);
376     if (!MaybeStr || !NumEntries)
377       return EmptyRange;
378     uint64_t EndOffset = DataOffset + *NumEntries * getHashDataEntryLength();
379     if (Key == *MaybeStr)
380       return make_range({*this, DataOffset},
381                         SameNameIterator{*this, EndOffset});
382     DataOffset = EndOffset;
383     StrOffset = readStringOffsetAt(DataOffset);
384   }
385 
386   return EmptyRange;
387 }
388 
389 std::optional<uint32_t>
idxOfHashInBucket(uint32_t HashToFind,uint32_t BucketIdx) const390 AppleAcceleratorTable::idxOfHashInBucket(uint32_t HashToFind,
391                                          uint32_t BucketIdx) const {
392   std::optional<uint32_t> HashStartIdx = readIthBucket(BucketIdx);
393   if (!HashStartIdx)
394     return std::nullopt;
395 
396   for (uint32_t HashIdx = *HashStartIdx; HashIdx < getNumHashes(); HashIdx++) {
397     std::optional<uint32_t> MaybeHash = readIthHash(HashIdx);
398     if (!MaybeHash || !wouldHashBeInBucket(*MaybeHash, BucketIdx))
399       break;
400     if (*MaybeHash == HashToFind)
401       return HashIdx;
402   }
403   return std::nullopt;
404 }
405 
readStringFromStrSection(uint64_t StringSectionOffset) const406 std::optional<StringRef> AppleAcceleratorTable::readStringFromStrSection(
407     uint64_t StringSectionOffset) const {
408   Error E = Error::success();
409   StringRef Str = StringSection.getCStrRef(&StringSectionOffset, &E);
410   if (E) {
411     consumeError(std::move(E));
412     return std::nullopt;
413   }
414   return Str;
415 }
416 
417 std::optional<uint32_t>
readU32FromAccel(uint64_t & Offset,bool UseRelocation) const418 AppleAcceleratorTable::readU32FromAccel(uint64_t &Offset,
419                                         bool UseRelocation) const {
420   Error E = Error::success();
421   uint32_t Data = UseRelocation
422                       ? AccelSection.getRelocatedValue(4, &Offset, nullptr, &E)
423                       : AccelSection.getU32(&Offset, &E);
424   if (E) {
425     consumeError(std::move(E));
426     return std::nullopt;
427   }
428   return Data;
429 }
430 
dump(ScopedPrinter & W) const431 void DWARFDebugNames::Header::dump(ScopedPrinter &W) const {
432   DictScope HeaderScope(W, "Header");
433   W.printHex("Length", UnitLength);
434   W.printString("Format", dwarf::FormatString(Format));
435   W.printNumber("Version", Version);
436   W.printNumber("CU count", CompUnitCount);
437   W.printNumber("Local TU count", LocalTypeUnitCount);
438   W.printNumber("Foreign TU count", ForeignTypeUnitCount);
439   W.printNumber("Bucket count", BucketCount);
440   W.printNumber("Name count", NameCount);
441   W.printHex("Abbreviations table size", AbbrevTableSize);
442   W.startLine() << "Augmentation: '" << AugmentationString << "'\n";
443 }
444 
extract(const DWARFDataExtractor & AS,uint64_t * Offset)445 Error DWARFDebugNames::Header::extract(const DWARFDataExtractor &AS,
446                                              uint64_t *Offset) {
447   auto HeaderError = [Offset = *Offset](Error E) {
448     return createStringError(errc::illegal_byte_sequence,
449                              "parsing .debug_names header at 0x%" PRIx64 ": %s",
450                              Offset, toString(std::move(E)).c_str());
451   };
452 
453   DataExtractor::Cursor C(*Offset);
454   std::tie(UnitLength, Format) = AS.getInitialLength(C);
455 
456   Version = AS.getU16(C);
457   AS.skip(C, 2); // padding
458   CompUnitCount = AS.getU32(C);
459   LocalTypeUnitCount = AS.getU32(C);
460   ForeignTypeUnitCount = AS.getU32(C);
461   BucketCount = AS.getU32(C);
462   NameCount = AS.getU32(C);
463   AbbrevTableSize = AS.getU32(C);
464   AugmentationStringSize = alignTo(AS.getU32(C), 4);
465 
466   if (!C)
467     return HeaderError(C.takeError());
468 
469   if (!AS.isValidOffsetForDataOfSize(C.tell(), AugmentationStringSize))
470     return HeaderError(createStringError(errc::illegal_byte_sequence,
471                                          "cannot read header augmentation"));
472   AugmentationString.resize(AugmentationStringSize);
473   AS.getU8(C, reinterpret_cast<uint8_t *>(AugmentationString.data()),
474            AugmentationStringSize);
475   *Offset = C.tell();
476   return C.takeError();
477 }
478 
dump(ScopedPrinter & W) const479 void DWARFDebugNames::Abbrev::dump(ScopedPrinter &W) const {
480   DictScope AbbrevScope(W, ("Abbreviation 0x" + Twine::utohexstr(Code)).str());
481   W.startLine() << formatv("Tag: {0}\n", Tag);
482 
483   for (const auto &Attr : Attributes)
484     W.startLine() << formatv("{0}: {1}\n", Attr.Index, Attr.Form);
485 }
486 
sentinelAttrEnc()487 static constexpr DWARFDebugNames::AttributeEncoding sentinelAttrEnc() {
488   return {dwarf::Index(0), dwarf::Form(0)};
489 }
490 
isSentinel(const DWARFDebugNames::AttributeEncoding & AE)491 static bool isSentinel(const DWARFDebugNames::AttributeEncoding &AE) {
492   return AE == sentinelAttrEnc();
493 }
494 
sentinelAbbrev()495 static DWARFDebugNames::Abbrev sentinelAbbrev() {
496   return DWARFDebugNames::Abbrev(0, dwarf::Tag(0), 0, {});
497 }
498 
isSentinel(const DWARFDebugNames::Abbrev & Abbr)499 static bool isSentinel(const DWARFDebugNames::Abbrev &Abbr) {
500   return Abbr.Code == 0;
501 }
502 
getEmptyKey()503 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getEmptyKey() {
504   return sentinelAbbrev();
505 }
506 
getTombstoneKey()507 DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getTombstoneKey() {
508   return DWARFDebugNames::Abbrev(~0, dwarf::Tag(0), 0, {});
509 }
510 
511 Expected<DWARFDebugNames::AttributeEncoding>
extractAttributeEncoding(uint64_t * Offset)512 DWARFDebugNames::NameIndex::extractAttributeEncoding(uint64_t *Offset) {
513   if (*Offset >= Offsets.EntriesBase) {
514     return createStringError(errc::illegal_byte_sequence,
515                              "Incorrectly terminated abbreviation table.");
516   }
517 
518   uint32_t Index = Section.AccelSection.getULEB128(Offset);
519   uint32_t Form = Section.AccelSection.getULEB128(Offset);
520   return AttributeEncoding(dwarf::Index(Index), dwarf::Form(Form));
521 }
522 
523 Expected<std::vector<DWARFDebugNames::AttributeEncoding>>
extractAttributeEncodings(uint64_t * Offset)524 DWARFDebugNames::NameIndex::extractAttributeEncodings(uint64_t *Offset) {
525   std::vector<AttributeEncoding> Result;
526   for (;;) {
527     auto AttrEncOr = extractAttributeEncoding(Offset);
528     if (!AttrEncOr)
529       return AttrEncOr.takeError();
530     if (isSentinel(*AttrEncOr))
531       return std::move(Result);
532 
533     Result.emplace_back(*AttrEncOr);
534   }
535 }
536 
537 Expected<DWARFDebugNames::Abbrev>
extractAbbrev(uint64_t * Offset)538 DWARFDebugNames::NameIndex::extractAbbrev(uint64_t *Offset) {
539   if (*Offset >= Offsets.EntriesBase) {
540     return createStringError(errc::illegal_byte_sequence,
541                              "Incorrectly terminated abbreviation table.");
542   }
543   const uint64_t AbbrevOffset = *Offset;
544   uint32_t Code = Section.AccelSection.getULEB128(Offset);
545   if (Code == 0)
546     return sentinelAbbrev();
547 
548   uint32_t Tag = Section.AccelSection.getULEB128(Offset);
549   auto AttrEncOr = extractAttributeEncodings(Offset);
550   if (!AttrEncOr)
551     return AttrEncOr.takeError();
552   return Abbrev(Code, dwarf::Tag(Tag), AbbrevOffset, std::move(*AttrEncOr));
553 }
554 
555 DWARFDebugNames::DWARFDebugNamesOffsets
findDebugNamesOffsets(uint64_t EndOfHeaderOffset,const DWARFDebugNames::Header & Hdr)556 dwarf::findDebugNamesOffsets(uint64_t EndOfHeaderOffset,
557                              const DWARFDebugNames::Header &Hdr) {
558   uint64_t DwarfSize = getDwarfOffsetByteSize(Hdr.Format);
559   DWARFDebugNames::DWARFDebugNamesOffsets Ret;
560   Ret.CUsBase = EndOfHeaderOffset;
561   Ret.BucketsBase = Ret.CUsBase + Hdr.CompUnitCount * DwarfSize +
562                     Hdr.LocalTypeUnitCount * DwarfSize +
563                     Hdr.ForeignTypeUnitCount * 8;
564   Ret.HashesBase = Ret.BucketsBase + Hdr.BucketCount * 4;
565   Ret.StringOffsetsBase =
566       Ret.HashesBase + (Hdr.BucketCount > 0 ? Hdr.NameCount * 4 : 0);
567   Ret.EntryOffsetsBase = Ret.StringOffsetsBase + Hdr.NameCount * DwarfSize;
568   Ret.EntriesBase =
569       Ret.EntryOffsetsBase + Hdr.NameCount * DwarfSize + Hdr.AbbrevTableSize;
570   return Ret;
571 }
572 
extract()573 Error DWARFDebugNames::NameIndex::extract() {
574   const DWARFDataExtractor &AS = Section.AccelSection;
575   uint64_t EndOfHeaderOffset = Base;
576   if (Error E = Hdr.extract(AS, &EndOfHeaderOffset))
577     return E;
578 
579   const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
580   Offsets = dwarf::findDebugNamesOffsets(EndOfHeaderOffset, Hdr);
581 
582   uint64_t Offset =
583       Offsets.EntryOffsetsBase + (Hdr.NameCount * SectionOffsetSize);
584 
585   if (!AS.isValidOffsetForDataOfSize(Offset, Hdr.AbbrevTableSize))
586     return createStringError(errc::illegal_byte_sequence,
587                              "Section too small: cannot read abbreviations.");
588 
589   Offsets.EntriesBase = Offset + Hdr.AbbrevTableSize;
590 
591   for (;;) {
592     auto AbbrevOr = extractAbbrev(&Offset);
593     if (!AbbrevOr)
594       return AbbrevOr.takeError();
595     if (isSentinel(*AbbrevOr))
596       return Error::success();
597 
598     if (!Abbrevs.insert(std::move(*AbbrevOr)).second)
599       return createStringError(errc::invalid_argument,
600                                "Duplicate abbreviation code.");
601   }
602 }
603 
Entry(const NameIndex & NameIdx,const Abbrev & Abbr)604 DWARFDebugNames::Entry::Entry(const NameIndex &NameIdx, const Abbrev &Abbr)
605     : NameIdx(&NameIdx), Abbr(&Abbr) {
606   // This merely creates form values. It is up to the caller
607   // (NameIndex::getEntry) to populate them.
608   Values.reserve(Abbr.Attributes.size());
609   for (const auto &Attr : Abbr.Attributes)
610     Values.emplace_back(Attr.Form);
611 }
612 
613 std::optional<DWARFFormValue>
lookup(dwarf::Index Index) const614 DWARFDebugNames::Entry::lookup(dwarf::Index Index) const {
615   assert(Abbr->Attributes.size() == Values.size());
616   for (auto Tuple : zip_first(Abbr->Attributes, Values)) {
617     if (std::get<0>(Tuple).Index == Index)
618       return std::get<1>(Tuple);
619   }
620   return std::nullopt;
621 }
622 
hasParentInformation() const623 bool DWARFDebugNames::Entry::hasParentInformation() const {
624   return lookup(dwarf::DW_IDX_parent).has_value();
625 }
626 
getDIEUnitOffset() const627 std::optional<uint64_t> DWARFDebugNames::Entry::getDIEUnitOffset() const {
628   if (std::optional<DWARFFormValue> Off = lookup(dwarf::DW_IDX_die_offset))
629     return Off->getAsReferenceUVal();
630   return std::nullopt;
631 }
632 
getRelatedCUIndex() const633 std::optional<uint64_t> DWARFDebugNames::Entry::getRelatedCUIndex() const {
634   // Return the DW_IDX_compile_unit attribute value if it is specified.
635   if (std::optional<DWARFFormValue> Off = lookup(dwarf::DW_IDX_compile_unit))
636     return Off->getAsUnsignedConstant();
637   // In a per-CU index, the entries without a DW_IDX_compile_unit attribute
638   // implicitly refer to the single CU.
639   if (NameIdx->getCUCount() == 1)
640     return 0;
641   return std::nullopt;
642 }
643 
getCUIndex() const644 std::optional<uint64_t> DWARFDebugNames::Entry::getCUIndex() const {
645   // Return the DW_IDX_compile_unit attribute value but only if we don't have a
646   // DW_IDX_type_unit attribute. Use Entry::getRelatedCUIndex() to get the
647   // associated CU index if this behaviour is not desired.
648   if (lookup(dwarf::DW_IDX_type_unit).has_value())
649     return std::nullopt;
650   return getRelatedCUIndex();
651 }
652 
getCUOffset() const653 std::optional<uint64_t> DWARFDebugNames::Entry::getCUOffset() const {
654   std::optional<uint64_t> Index = getCUIndex();
655   if (!Index || *Index >= NameIdx->getCUCount())
656     return std::nullopt;
657   return NameIdx->getCUOffset(*Index);
658 }
659 
getRelatedCUOffset() const660 std::optional<uint64_t> DWARFDebugNames::Entry::getRelatedCUOffset() const {
661   std::optional<uint64_t> Index = getRelatedCUIndex();
662   if (!Index || *Index >= NameIdx->getCUCount())
663     return std::nullopt;
664   return NameIdx->getCUOffset(*Index);
665 }
666 
getLocalTUOffset() const667 std::optional<uint64_t> DWARFDebugNames::Entry::getLocalTUOffset() const {
668   std::optional<uint64_t> Index = getLocalTUIndex();
669   if (!Index || *Index >= NameIdx->getLocalTUCount())
670     return std::nullopt;
671   return NameIdx->getLocalTUOffset(*Index);
672 }
673 
674 std::optional<uint64_t>
getForeignTUTypeSignature() const675 DWARFDebugNames::Entry::getForeignTUTypeSignature() const {
676   std::optional<uint64_t> Index = getLocalTUIndex();
677   const uint32_t NumLocalTUs = NameIdx->getLocalTUCount();
678   if (!Index || *Index < NumLocalTUs)
679     return std::nullopt; // Invalid TU index or TU index is for a local TU
680   // The foreign TU index is the TU index minus the number of local TUs.
681   const uint64_t ForeignTUIndex = *Index - NumLocalTUs;
682   if (ForeignTUIndex >= NameIdx->getForeignTUCount())
683     return std::nullopt; // Invalid foreign TU index.
684   return NameIdx->getForeignTUSignature(ForeignTUIndex);
685 }
686 
getLocalTUIndex() const687 std::optional<uint64_t> DWARFDebugNames::Entry::getLocalTUIndex() const {
688   if (std::optional<DWARFFormValue> Off = lookup(dwarf::DW_IDX_type_unit))
689     return Off->getAsUnsignedConstant();
690   return std::nullopt;
691 }
692 
693 Expected<std::optional<DWARFDebugNames::Entry>>
getParentDIEEntry() const694 DWARFDebugNames::Entry::getParentDIEEntry() const {
695   // The offset of the accelerator table entry for the parent.
696   std::optional<DWARFFormValue> ParentEntryOff = lookup(dwarf::DW_IDX_parent);
697   assert(ParentEntryOff.has_value() && "hasParentInformation() must be called");
698 
699   if (ParentEntryOff->getForm() == dwarf::Form::DW_FORM_flag_present)
700     return std::nullopt;
701   return NameIdx->getEntryAtRelativeOffset(ParentEntryOff->getRawUValue());
702 }
703 
dumpParentIdx(ScopedPrinter & W,const DWARFFormValue & FormValue) const704 void DWARFDebugNames::Entry::dumpParentIdx(
705     ScopedPrinter &W, const DWARFFormValue &FormValue) const {
706   Expected<std::optional<Entry>> ParentEntry = getParentDIEEntry();
707   if (!ParentEntry) {
708     W.getOStream() << "<invalid offset data>";
709     consumeError(ParentEntry.takeError());
710     return;
711   }
712 
713   if (!ParentEntry->has_value()) {
714     W.getOStream() << "<parent not indexed>";
715     return;
716   }
717 
718   auto AbsoluteOffset = NameIdx->Offsets.EntriesBase + FormValue.getRawUValue();
719   W.getOStream() << "Entry @ 0x" + Twine::utohexstr(AbsoluteOffset);
720 }
721 
dump(ScopedPrinter & W) const722 void DWARFDebugNames::Entry::dump(ScopedPrinter &W) const {
723   W.startLine() << formatv("Abbrev: {0:x}\n", Abbr->Code);
724   W.startLine() << formatv("Tag: {0}\n", Abbr->Tag);
725   assert(Abbr->Attributes.size() == Values.size());
726   for (auto Tuple : zip_first(Abbr->Attributes, Values)) {
727     auto Index = std::get<0>(Tuple).Index;
728     W.startLine() << formatv("{0}: ", Index);
729 
730     auto FormValue = std::get<1>(Tuple);
731     if (Index == dwarf::Index::DW_IDX_parent)
732       dumpParentIdx(W, FormValue);
733     else
734       FormValue.dump(W.getOStream());
735     W.getOStream() << '\n';
736   }
737 }
738 
739 char DWARFDebugNames::SentinelError::ID;
convertToErrorCode() const740 std::error_code DWARFDebugNames::SentinelError::convertToErrorCode() const {
741   return inconvertibleErrorCode();
742 }
743 
getCUOffset(uint32_t CU) const744 uint64_t DWARFDebugNames::NameIndex::getCUOffset(uint32_t CU) const {
745   assert(CU < Hdr.CompUnitCount);
746   const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
747   uint64_t Offset = Offsets.CUsBase + SectionOffsetSize * CU;
748   return Section.AccelSection.getRelocatedValue(SectionOffsetSize, &Offset);
749 }
750 
getLocalTUOffset(uint32_t TU) const751 uint64_t DWARFDebugNames::NameIndex::getLocalTUOffset(uint32_t TU) const {
752   assert(TU < Hdr.LocalTypeUnitCount);
753   const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
754   uint64_t Offset =
755       Offsets.CUsBase + SectionOffsetSize * (Hdr.CompUnitCount + TU);
756   return Section.AccelSection.getRelocatedValue(SectionOffsetSize, &Offset);
757 }
758 
getForeignTUSignature(uint32_t TU) const759 uint64_t DWARFDebugNames::NameIndex::getForeignTUSignature(uint32_t TU) const {
760   assert(TU < Hdr.ForeignTypeUnitCount);
761   const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
762   uint64_t Offset =
763       Offsets.CUsBase +
764       SectionOffsetSize * (Hdr.CompUnitCount + Hdr.LocalTypeUnitCount) + 8 * TU;
765   return Section.AccelSection.getU64(&Offset);
766 }
767 
768 Expected<DWARFDebugNames::Entry>
getEntry(uint64_t * Offset) const769 DWARFDebugNames::NameIndex::getEntry(uint64_t *Offset) const {
770   const DWARFDataExtractor &AS = Section.AccelSection;
771   if (!AS.isValidOffset(*Offset))
772     return createStringError(errc::illegal_byte_sequence,
773                              "Incorrectly terminated entry list.");
774 
775   uint32_t AbbrevCode = AS.getULEB128(Offset);
776   if (AbbrevCode == 0)
777     return make_error<SentinelError>();
778 
779   const auto AbbrevIt = Abbrevs.find_as(AbbrevCode);
780   if (AbbrevIt == Abbrevs.end())
781     return createStringError(errc::invalid_argument, "Invalid abbreviation.");
782 
783   Entry E(*this, *AbbrevIt);
784 
785   dwarf::FormParams FormParams = {Hdr.Version, 0, Hdr.Format};
786   for (auto &Value : E.Values) {
787     if (!Value.extractValue(AS, Offset, FormParams))
788       return createStringError(errc::io_error,
789                                "Error extracting index attribute values.");
790   }
791   return std::move(E);
792 }
793 
794 DWARFDebugNames::NameTableEntry
getNameTableEntry(uint32_t Index) const795 DWARFDebugNames::NameIndex::getNameTableEntry(uint32_t Index) const {
796   assert(0 < Index && Index <= Hdr.NameCount);
797   const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
798   uint64_t StringOffsetOffset =
799       Offsets.StringOffsetsBase + SectionOffsetSize * (Index - 1);
800   uint64_t EntryOffsetOffset =
801       Offsets.EntryOffsetsBase + SectionOffsetSize * (Index - 1);
802   const DWARFDataExtractor &AS = Section.AccelSection;
803 
804   uint64_t StringOffset =
805       AS.getRelocatedValue(SectionOffsetSize, &StringOffsetOffset);
806   uint64_t EntryOffset = AS.getUnsigned(&EntryOffsetOffset, SectionOffsetSize);
807   EntryOffset += Offsets.EntriesBase;
808   return {Section.StringSection, Index, StringOffset, EntryOffset};
809 }
810 
811 uint32_t
getBucketArrayEntry(uint32_t Bucket) const812 DWARFDebugNames::NameIndex::getBucketArrayEntry(uint32_t Bucket) const {
813   assert(Bucket < Hdr.BucketCount);
814   uint64_t BucketOffset = Offsets.BucketsBase + 4 * Bucket;
815   return Section.AccelSection.getU32(&BucketOffset);
816 }
817 
getHashArrayEntry(uint32_t Index) const818 uint32_t DWARFDebugNames::NameIndex::getHashArrayEntry(uint32_t Index) const {
819   assert(0 < Index && Index <= Hdr.NameCount);
820   uint64_t HashOffset = Offsets.HashesBase + 4 * (Index - 1);
821   return Section.AccelSection.getU32(&HashOffset);
822 }
823 
824 // Returns true if we should continue scanning for entries, false if this is the
825 // last (sentinel) entry). In case of a parsing error we also return false, as
826 // it's not possible to recover this entry list (but the other lists may still
827 // parse OK).
dumpEntry(ScopedPrinter & W,uint64_t * Offset) const828 bool DWARFDebugNames::NameIndex::dumpEntry(ScopedPrinter &W,
829                                            uint64_t *Offset) const {
830   uint64_t EntryId = *Offset;
831   auto EntryOr = getEntry(Offset);
832   if (!EntryOr) {
833     handleAllErrors(EntryOr.takeError(), [](const SentinelError &) {},
834                     [&W](const ErrorInfoBase &EI) { EI.log(W.startLine()); });
835     return false;
836   }
837 
838   DictScope EntryScope(W, ("Entry @ 0x" + Twine::utohexstr(EntryId)).str());
839   EntryOr->dump(W);
840   return true;
841 }
842 
dumpName(ScopedPrinter & W,const NameTableEntry & NTE,std::optional<uint32_t> Hash) const843 void DWARFDebugNames::NameIndex::dumpName(ScopedPrinter &W,
844                                           const NameTableEntry &NTE,
845                                           std::optional<uint32_t> Hash) const {
846   DictScope NameScope(W, ("Name " + Twine(NTE.getIndex())).str());
847   if (Hash)
848     W.printHex("Hash", *Hash);
849 
850   W.startLine() << format("String: 0x%08" PRIx64, NTE.getStringOffset());
851   W.getOStream() << " \"" << NTE.getString() << "\"\n";
852 
853   uint64_t EntryOffset = NTE.getEntryOffset();
854   while (dumpEntry(W, &EntryOffset))
855     /*empty*/;
856 }
857 
dumpCUs(ScopedPrinter & W) const858 void DWARFDebugNames::NameIndex::dumpCUs(ScopedPrinter &W) const {
859   ListScope CUScope(W, "Compilation Unit offsets");
860   for (uint32_t CU = 0; CU < Hdr.CompUnitCount; ++CU)
861     W.startLine() << format("CU[%u]: 0x%08" PRIx64 "\n", CU, getCUOffset(CU));
862 }
863 
dumpLocalTUs(ScopedPrinter & W) const864 void DWARFDebugNames::NameIndex::dumpLocalTUs(ScopedPrinter &W) const {
865   if (Hdr.LocalTypeUnitCount == 0)
866     return;
867 
868   ListScope TUScope(W, "Local Type Unit offsets");
869   for (uint32_t TU = 0; TU < Hdr.LocalTypeUnitCount; ++TU)
870     W.startLine() << format("LocalTU[%u]: 0x%08" PRIx64 "\n", TU,
871                             getLocalTUOffset(TU));
872 }
873 
dumpForeignTUs(ScopedPrinter & W) const874 void DWARFDebugNames::NameIndex::dumpForeignTUs(ScopedPrinter &W) const {
875   if (Hdr.ForeignTypeUnitCount == 0)
876     return;
877 
878   ListScope TUScope(W, "Foreign Type Unit signatures");
879   for (uint32_t TU = 0; TU < Hdr.ForeignTypeUnitCount; ++TU) {
880     W.startLine() << format("ForeignTU[%u]: 0x%016" PRIx64 "\n", TU,
881                             getForeignTUSignature(TU));
882   }
883 }
884 
dumpAbbreviations(ScopedPrinter & W) const885 void DWARFDebugNames::NameIndex::dumpAbbreviations(ScopedPrinter &W) const {
886   ListScope AbbrevsScope(W, "Abbreviations");
887   std::vector<const Abbrev *> AbbrevsVect;
888   for (const DWARFDebugNames::Abbrev &Abbr : Abbrevs)
889     AbbrevsVect.push_back(&Abbr);
890   llvm::sort(AbbrevsVect, [](const Abbrev *LHS, const Abbrev *RHS) {
891     return LHS->AbbrevOffset < RHS->AbbrevOffset;
892   });
893   for (const DWARFDebugNames::Abbrev *Abbr : AbbrevsVect)
894     Abbr->dump(W);
895 }
896 
dumpBucket(ScopedPrinter & W,uint32_t Bucket) const897 void DWARFDebugNames::NameIndex::dumpBucket(ScopedPrinter &W,
898                                             uint32_t Bucket) const {
899   ListScope BucketScope(W, ("Bucket " + Twine(Bucket)).str());
900   uint32_t Index = getBucketArrayEntry(Bucket);
901   if (Index == 0) {
902     W.printString("EMPTY");
903     return;
904   }
905   if (Index > Hdr.NameCount) {
906     W.printString("Name index is invalid");
907     return;
908   }
909 
910   for (; Index <= Hdr.NameCount; ++Index) {
911     uint32_t Hash = getHashArrayEntry(Index);
912     if (Hash % Hdr.BucketCount != Bucket)
913       break;
914 
915     dumpName(W, getNameTableEntry(Index), Hash);
916   }
917 }
918 
dump(ScopedPrinter & W) const919 LLVM_DUMP_METHOD void DWARFDebugNames::NameIndex::dump(ScopedPrinter &W) const {
920   DictScope UnitScope(W, ("Name Index @ 0x" + Twine::utohexstr(Base)).str());
921   Hdr.dump(W);
922   dumpCUs(W);
923   dumpLocalTUs(W);
924   dumpForeignTUs(W);
925   dumpAbbreviations(W);
926 
927   if (Hdr.BucketCount > 0) {
928     for (uint32_t Bucket = 0; Bucket < Hdr.BucketCount; ++Bucket)
929       dumpBucket(W, Bucket);
930     return;
931   }
932 
933   W.startLine() << "Hash table not present\n";
934   for (const NameTableEntry &NTE : *this)
935     dumpName(W, NTE, std::nullopt);
936 }
937 
extract()938 Error DWARFDebugNames::extract() {
939   uint64_t Offset = 0;
940   while (AccelSection.isValidOffset(Offset)) {
941     NameIndex Next(*this, Offset);
942     if (Error E = Next.extract())
943       return E;
944     Offset = Next.getNextUnitOffset();
945     NameIndices.push_back(std::move(Next));
946   }
947   return Error::success();
948 }
949 
950 iterator_range<DWARFDebugNames::ValueIterator>
equal_range(StringRef Key) const951 DWARFDebugNames::NameIndex::equal_range(StringRef Key) const {
952   return make_range(ValueIterator(*this, Key), ValueIterator());
953 }
954 
dump(raw_ostream & OS) const955 LLVM_DUMP_METHOD void DWARFDebugNames::dump(raw_ostream &OS) const {
956   ScopedPrinter W(OS);
957   for (const NameIndex &NI : NameIndices)
958     NI.dump(W);
959 }
960 
961 std::optional<uint64_t>
findEntryOffsetInCurrentIndex()962 DWARFDebugNames::ValueIterator::findEntryOffsetInCurrentIndex() {
963   const Header &Hdr = CurrentIndex->Hdr;
964   if (Hdr.BucketCount == 0) {
965     // No Hash Table, We need to search through all names in the Name Index.
966     for (const NameTableEntry &NTE : *CurrentIndex) {
967       if (NTE.sameNameAs(Key))
968         return NTE.getEntryOffset();
969     }
970     return std::nullopt;
971   }
972 
973   // The Name Index has a Hash Table, so use that to speed up the search.
974   // Compute the Key Hash, if it has not been done already.
975   if (!Hash)
976     Hash = caseFoldingDjbHash(Key);
977   uint32_t Bucket = *Hash % Hdr.BucketCount;
978   uint32_t Index = CurrentIndex->getBucketArrayEntry(Bucket);
979   if (Index == 0)
980     return std::nullopt; // Empty bucket
981 
982   for (; Index <= Hdr.NameCount; ++Index) {
983     uint32_t HashAtIndex = CurrentIndex->getHashArrayEntry(Index);
984     if (HashAtIndex % Hdr.BucketCount != Bucket)
985       return std::nullopt; // End of bucket
986     // Only compare names if the hashes match.
987     if (HashAtIndex != Hash)
988       continue;
989 
990     NameTableEntry NTE = CurrentIndex->getNameTableEntry(Index);
991     if (NTE.sameNameAs(Key))
992       return NTE.getEntryOffset();
993   }
994   return std::nullopt;
995 }
996 
getEntryAtCurrentOffset()997 bool DWARFDebugNames::ValueIterator::getEntryAtCurrentOffset() {
998   auto EntryOr = CurrentIndex->getEntry(&DataOffset);
999   if (!EntryOr) {
1000     consumeError(EntryOr.takeError());
1001     return false;
1002   }
1003   CurrentEntry = std::move(*EntryOr);
1004   return true;
1005 }
1006 
findInCurrentIndex()1007 bool DWARFDebugNames::ValueIterator::findInCurrentIndex() {
1008   std::optional<uint64_t> Offset = findEntryOffsetInCurrentIndex();
1009   if (!Offset)
1010     return false;
1011   DataOffset = *Offset;
1012   return getEntryAtCurrentOffset();
1013 }
1014 
searchFromStartOfCurrentIndex()1015 void DWARFDebugNames::ValueIterator::searchFromStartOfCurrentIndex() {
1016   for (const NameIndex *End = CurrentIndex->Section.NameIndices.end();
1017        CurrentIndex != End; ++CurrentIndex) {
1018     if (findInCurrentIndex())
1019       return;
1020   }
1021   setEnd();
1022 }
1023 
next()1024 void DWARFDebugNames::ValueIterator::next() {
1025   assert(CurrentIndex && "Incrementing an end() iterator?");
1026 
1027   // First try the next entry in the current Index.
1028   if (getEntryAtCurrentOffset())
1029     return;
1030 
1031   // If we're a local iterator or we have reached the last Index, we're done.
1032   if (IsLocal || CurrentIndex == &CurrentIndex->Section.NameIndices.back()) {
1033     setEnd();
1034     return;
1035   }
1036 
1037   // Otherwise, try the next index.
1038   ++CurrentIndex;
1039   searchFromStartOfCurrentIndex();
1040 }
1041 
ValueIterator(const DWARFDebugNames & AccelTable,StringRef Key)1042 DWARFDebugNames::ValueIterator::ValueIterator(const DWARFDebugNames &AccelTable,
1043                                               StringRef Key)
1044     : CurrentIndex(AccelTable.NameIndices.begin()), IsLocal(false),
1045       Key(std::string(Key)) {
1046   searchFromStartOfCurrentIndex();
1047 }
1048 
ValueIterator(const DWARFDebugNames::NameIndex & NI,StringRef Key)1049 DWARFDebugNames::ValueIterator::ValueIterator(
1050     const DWARFDebugNames::NameIndex &NI, StringRef Key)
1051     : CurrentIndex(&NI), IsLocal(true), Key(std::string(Key)) {
1052   if (!findInCurrentIndex())
1053     setEnd();
1054 }
1055 
1056 iterator_range<DWARFDebugNames::ValueIterator>
equal_range(StringRef Key) const1057 DWARFDebugNames::equal_range(StringRef Key) const {
1058   if (NameIndices.empty())
1059     return make_range(ValueIterator(), ValueIterator());
1060   return make_range(ValueIterator(*this, Key), ValueIterator());
1061 }
1062 
1063 const DWARFDebugNames::NameIndex *
getCUNameIndex(uint64_t CUOffset)1064 DWARFDebugNames::getCUNameIndex(uint64_t CUOffset) {
1065   if (CUToNameIndex.size() == 0 && NameIndices.size() > 0) {
1066     for (const auto &NI : *this) {
1067       for (uint32_t CU = 0; CU < NI.getCUCount(); ++CU)
1068         CUToNameIndex.try_emplace(NI.getCUOffset(CU), &NI);
1069     }
1070   }
1071   return CUToNameIndex.lookup(CUOffset);
1072 }
1073 
isObjCSelector(StringRef Name)1074 static bool isObjCSelector(StringRef Name) {
1075   return Name.size() > 2 && (Name[0] == '-' || Name[0] == '+') &&
1076          (Name[1] == '[');
1077 }
1078 
getObjCNamesIfSelector(StringRef Name)1079 std::optional<ObjCSelectorNames> llvm::getObjCNamesIfSelector(StringRef Name) {
1080   if (!isObjCSelector(Name))
1081     return std::nullopt;
1082   // "-[Atom setMass:]"
1083   StringRef ClassNameStart(Name.drop_front(2));
1084   size_t FirstSpace = ClassNameStart.find(' ');
1085   if (FirstSpace == StringRef::npos)
1086     return std::nullopt;
1087 
1088   StringRef SelectorStart = ClassNameStart.drop_front(FirstSpace + 1);
1089   if (!SelectorStart.size())
1090     return std::nullopt;
1091 
1092   ObjCSelectorNames Ans;
1093   Ans.ClassName = ClassNameStart.take_front(FirstSpace);
1094   Ans.Selector = SelectorStart.drop_back(); // drop ']';
1095 
1096   // "-[Class(Category) selector :withArg ...]"
1097   if (Ans.ClassName.back() == ')') {
1098     size_t OpenParens = Ans.ClassName.find('(');
1099     if (OpenParens != StringRef::npos) {
1100       Ans.ClassNameNoCategory = Ans.ClassName.take_front(OpenParens);
1101 
1102       Ans.MethodNameNoCategory = Name.take_front(OpenParens + 2);
1103       // FIXME: The missing space here may be a bug, but dsymutil-classic also
1104       // does it this way.
1105       append_range(*Ans.MethodNameNoCategory, SelectorStart);
1106     }
1107   }
1108   return Ans;
1109 }
1110 
StripTemplateParameters(StringRef Name)1111 std::optional<StringRef> llvm::StripTemplateParameters(StringRef Name) {
1112   // We are looking for template parameters to strip from Name. e.g.
1113   //
1114   //  operator<<B>
1115   //
1116   // We look for > at the end but if it does not contain any < then we
1117   // have something like operator>>. We check for the operator<=> case.
1118   if (!Name.ends_with(">") || Name.count("<") == 0 || Name.ends_with("<=>"))
1119     return {};
1120 
1121   // How many < until we have the start of the template parameters.
1122   size_t NumLeftAnglesToSkip = 1;
1123 
1124   // If we have operator<=> then we need to skip its < as well.
1125   NumLeftAnglesToSkip += Name.count("<=>");
1126 
1127   size_t RightAngleCount = Name.count('>');
1128   size_t LeftAngleCount = Name.count('<');
1129 
1130   // If we have more < than > we have operator< or operator<<
1131   // we to account for their < as well.
1132   if (LeftAngleCount > RightAngleCount)
1133     NumLeftAnglesToSkip += LeftAngleCount - RightAngleCount;
1134 
1135   size_t StartOfTemplate = 0;
1136   while (NumLeftAnglesToSkip--)
1137     StartOfTemplate = Name.find('<', StartOfTemplate) + 1;
1138 
1139   return Name.substr(0, StartOfTemplate - 1);
1140 }
1141