1//===- llvm/CodeGen/AsmPrinter/AccelTable.cpp - Accelerator Tables --------===//
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// This file contains support for writing accelerator tables.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/CodeGen/AccelTable.h"
14#include "DwarfCompileUnit.h"
15#include "llvm/ADT/STLExtras.h"
16#include "llvm/ADT/StringMap.h"
17#include "llvm/ADT/Twine.h"
18#include "llvm/BinaryFormat/Dwarf.h"
19#include "llvm/CodeGen/AsmPrinter.h"
20#include "llvm/CodeGen/DIE.h"
21#include "llvm/MC/MCExpr.h"
22#include "llvm/MC/MCStreamer.h"
23#include "llvm/MC/MCSymbol.h"
24#include "llvm/Support/raw_ostream.h"
25#include "llvm/Target/TargetLoweringObjectFile.h"
26#include <algorithm>
27#include <cstddef>
28#include <cstdint>
29#include <limits>
30#include <vector>
31
32using namespace llvm;
33
34void AccelTableBase::computeBucketCount() {
35  // First get the number of unique hashes.
36  std::vector<uint32_t> Uniques;
37  Uniques.reserve(Entries.size());
38  for (const auto &E : Entries)
39    Uniques.push_back(E.second.HashValue);
40  array_pod_sort(Uniques.begin(), Uniques.end());
41  std::vector<uint32_t>::iterator P =
42      std::unique(Uniques.begin(), Uniques.end());
43
44  UniqueHashCount = std::distance(Uniques.begin(), P);
45
46  if (UniqueHashCount > 1024)
47    BucketCount = UniqueHashCount / 4;
48  else if (UniqueHashCount > 16)
49    BucketCount = UniqueHashCount / 2;
50  else
51    BucketCount = std::max<uint32_t>(UniqueHashCount, 1);
52}
53
54void AccelTableBase::finalize(AsmPrinter *Asm, StringRef Prefix) {
55  // Create the individual hash data outputs.
56  for (auto &E : Entries) {
57    // Unique the entries.
58    llvm::stable_sort(E.second.Values,
59                      [](const AccelTableData *A, const AccelTableData *B) {
60                        return *A < *B;
61                      });
62    E.second.Values.erase(
63        std::unique(E.second.Values.begin(), E.second.Values.end()),
64        E.second.Values.end());
65  }
66
67  // Figure out how many buckets we need, then compute the bucket contents and
68  // the final ordering. The hashes and offsets can be emitted by walking these
69  // data structures. We add temporary symbols to the data so they can be
70  // referenced when emitting the offsets.
71  computeBucketCount();
72
73  // Compute bucket contents and final ordering.
74  Buckets.resize(BucketCount);
75  for (auto &E : Entries) {
76    uint32_t Bucket = E.second.HashValue % BucketCount;
77    Buckets[Bucket].push_back(&E.second);
78    E.second.Sym = Asm->createTempSymbol(Prefix);
79  }
80
81  // Sort the contents of the buckets by hash value so that hash collisions end
82  // up together. Stable sort makes testing easier and doesn't cost much more.
83  for (auto &Bucket : Buckets)
84    llvm::stable_sort(Bucket, [](HashData *LHS, HashData *RHS) {
85      return LHS->HashValue < RHS->HashValue;
86    });
87}
88
89namespace {
90/// Base class for writing out Accelerator tables. It holds the common
91/// functionality for the two Accelerator table types.
92class AccelTableWriter {
93protected:
94  AsmPrinter *const Asm;          ///< Destination.
95  const AccelTableBase &Contents; ///< Data to emit.
96
97  /// Controls whether to emit duplicate hash and offset table entries for names
98  /// with identical hashes. Apple tables don't emit duplicate entries, DWARF v5
99  /// tables do.
100  const bool SkipIdenticalHashes;
101
102  void emitHashes() const;
103
104  /// Emit offsets to lists of entries with identical names. The offsets are
105  /// relative to the Base argument.
106  void emitOffsets(const MCSymbol *Base) const;
107
108public:
109  AccelTableWriter(AsmPrinter *Asm, const AccelTableBase &Contents,
110                   bool SkipIdenticalHashes)
111      : Asm(Asm), Contents(Contents), SkipIdenticalHashes(SkipIdenticalHashes) {
112  }
113};
114
115class AppleAccelTableWriter : public AccelTableWriter {
116  using Atom = AppleAccelTableData::Atom;
117
118  /// The fixed header of an Apple Accelerator Table.
119  struct Header {
120    uint32_t Magic = MagicHash;
121    uint16_t Version = 1;
122    uint16_t HashFunction = dwarf::DW_hash_function_djb;
123    uint32_t BucketCount;
124    uint32_t HashCount;
125    uint32_t HeaderDataLength;
126
127    /// 'HASH' magic value to detect endianness.
128    static const uint32_t MagicHash = 0x48415348;
129
130    Header(uint32_t BucketCount, uint32_t UniqueHashCount, uint32_t DataLength)
131        : BucketCount(BucketCount), HashCount(UniqueHashCount),
132          HeaderDataLength(DataLength) {}
133
134    void emit(AsmPrinter *Asm) const;
135#ifndef NDEBUG
136    void print(raw_ostream &OS) const;
137    void dump() const { print(dbgs()); }
138#endif
139  };
140
141  /// The HeaderData describes the structure of an Apple accelerator table
142  /// through a list of Atoms.
143  struct HeaderData {
144    /// In the case of data that is referenced via DW_FORM_ref_* the offset
145    /// base is used to describe the offset for all forms in the list of atoms.
146    uint32_t DieOffsetBase;
147
148    const SmallVector<Atom, 4> Atoms;
149
150    HeaderData(ArrayRef<Atom> AtomList, uint32_t Offset = 0)
151        : DieOffsetBase(Offset), Atoms(AtomList.begin(), AtomList.end()) {}
152
153    void emit(AsmPrinter *Asm) const;
154#ifndef NDEBUG
155    void print(raw_ostream &OS) const;
156    void dump() const { print(dbgs()); }
157#endif
158  };
159
160  Header Header;
161  HeaderData HeaderData;
162  const MCSymbol *SecBegin;
163
164  void emitBuckets() const;
165  void emitData() const;
166
167public:
168  AppleAccelTableWriter(AsmPrinter *Asm, const AccelTableBase &Contents,
169                        ArrayRef<Atom> Atoms, const MCSymbol *SecBegin)
170      : AccelTableWriter(Asm, Contents, true),
171        Header(Contents.getBucketCount(), Contents.getUniqueHashCount(),
172               8 + (Atoms.size() * 4)),
173        HeaderData(Atoms), SecBegin(SecBegin) {}
174
175  void emit() const;
176
177#ifndef NDEBUG
178  void print(raw_ostream &OS) const;
179  void dump() const { print(dbgs()); }
180#endif
181};
182
183/// Class responsible for emitting a DWARF v5 Accelerator Table. The only
184/// public function is emit(), which performs the actual emission.
185///
186/// The class is templated in its data type. This allows us to emit both dyamic
187/// and static data entries. A callback abstract the logic to provide a CU
188/// index for a given entry, which is different per data type, but identical
189/// for every entry in the same table.
190template <typename DataT>
191class Dwarf5AccelTableWriter : public AccelTableWriter {
192  struct Header {
193    uint32_t UnitLength = 0;
194    uint16_t Version = 5;
195    uint16_t Padding = 0;
196    uint32_t CompUnitCount;
197    uint32_t LocalTypeUnitCount = 0;
198    uint32_t ForeignTypeUnitCount = 0;
199    uint32_t BucketCount;
200    uint32_t NameCount;
201    uint32_t AbbrevTableSize = 0;
202    uint32_t AugmentationStringSize = sizeof(AugmentationString);
203    char AugmentationString[8] = {'L', 'L', 'V', 'M', '0', '7', '0', '0'};
204
205    Header(uint32_t CompUnitCount, uint32_t BucketCount, uint32_t NameCount)
206        : CompUnitCount(CompUnitCount), BucketCount(BucketCount),
207          NameCount(NameCount) {}
208
209    void emit(const Dwarf5AccelTableWriter &Ctx) const;
210  };
211  struct AttributeEncoding {
212    dwarf::Index Index;
213    dwarf::Form Form;
214  };
215
216  Header Header;
217  DenseMap<uint32_t, SmallVector<AttributeEncoding, 2>> Abbreviations;
218  ArrayRef<MCSymbol *> CompUnits;
219  llvm::function_ref<unsigned(const DataT &)> getCUIndexForEntry;
220  MCSymbol *ContributionStart = Asm->createTempSymbol("names_start");
221  MCSymbol *ContributionEnd = Asm->createTempSymbol("names_end");
222  MCSymbol *AbbrevStart = Asm->createTempSymbol("names_abbrev_start");
223  MCSymbol *AbbrevEnd = Asm->createTempSymbol("names_abbrev_end");
224  MCSymbol *EntryPool = Asm->createTempSymbol("names_entries");
225
226  DenseSet<uint32_t> getUniqueTags() const;
227
228  // Right now, we emit uniform attributes for all tags.
229  SmallVector<AttributeEncoding, 2> getUniformAttributes() const;
230
231  void emitCUList() const;
232  void emitBuckets() const;
233  void emitStringOffsets() const;
234  void emitAbbrevs() const;
235  void emitEntry(const DataT &Entry) const;
236  void emitData() const;
237
238public:
239  Dwarf5AccelTableWriter(
240      AsmPrinter *Asm, const AccelTableBase &Contents,
241      ArrayRef<MCSymbol *> CompUnits,
242      llvm::function_ref<unsigned(const DataT &)> GetCUIndexForEntry);
243
244  void emit() const;
245};
246} // namespace
247
248void AccelTableWriter::emitHashes() const {
249  uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
250  unsigned BucketIdx = 0;
251  for (auto &Bucket : Contents.getBuckets()) {
252    for (auto &Hash : Bucket) {
253      uint32_t HashValue = Hash->HashValue;
254      if (SkipIdenticalHashes && PrevHash == HashValue)
255        continue;
256      Asm->OutStreamer->AddComment("Hash in Bucket " + Twine(BucketIdx));
257      Asm->emitInt32(HashValue);
258      PrevHash = HashValue;
259    }
260    BucketIdx++;
261  }
262}
263
264void AccelTableWriter::emitOffsets(const MCSymbol *Base) const {
265  const auto &Buckets = Contents.getBuckets();
266  uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
267  for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
268    for (auto *Hash : Buckets[i]) {
269      uint32_t HashValue = Hash->HashValue;
270      if (SkipIdenticalHashes && PrevHash == HashValue)
271        continue;
272      PrevHash = HashValue;
273      Asm->OutStreamer->AddComment("Offset in Bucket " + Twine(i));
274      Asm->EmitLabelDifference(Hash->Sym, Base, sizeof(uint32_t));
275    }
276  }
277}
278
279void AppleAccelTableWriter::Header::emit(AsmPrinter *Asm) const {
280  Asm->OutStreamer->AddComment("Header Magic");
281  Asm->emitInt32(Magic);
282  Asm->OutStreamer->AddComment("Header Version");
283  Asm->emitInt16(Version);
284  Asm->OutStreamer->AddComment("Header Hash Function");
285  Asm->emitInt16(HashFunction);
286  Asm->OutStreamer->AddComment("Header Bucket Count");
287  Asm->emitInt32(BucketCount);
288  Asm->OutStreamer->AddComment("Header Hash Count");
289  Asm->emitInt32(HashCount);
290  Asm->OutStreamer->AddComment("Header Data Length");
291  Asm->emitInt32(HeaderDataLength);
292}
293
294void AppleAccelTableWriter::HeaderData::emit(AsmPrinter *Asm) const {
295  Asm->OutStreamer->AddComment("HeaderData Die Offset Base");
296  Asm->emitInt32(DieOffsetBase);
297  Asm->OutStreamer->AddComment("HeaderData Atom Count");
298  Asm->emitInt32(Atoms.size());
299
300  for (const Atom &A : Atoms) {
301    Asm->OutStreamer->AddComment(dwarf::AtomTypeString(A.Type));
302    Asm->emitInt16(A.Type);
303    Asm->OutStreamer->AddComment(dwarf::FormEncodingString(A.Form));
304    Asm->emitInt16(A.Form);
305  }
306}
307
308void AppleAccelTableWriter::emitBuckets() const {
309  const auto &Buckets = Contents.getBuckets();
310  unsigned index = 0;
311  for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
312    Asm->OutStreamer->AddComment("Bucket " + Twine(i));
313    if (!Buckets[i].empty())
314      Asm->emitInt32(index);
315    else
316      Asm->emitInt32(std::numeric_limits<uint32_t>::max());
317    // Buckets point in the list of hashes, not to the data. Do not increment
318    // the index multiple times in case of hash collisions.
319    uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
320    for (auto *HD : Buckets[i]) {
321      uint32_t HashValue = HD->HashValue;
322      if (PrevHash != HashValue)
323        ++index;
324      PrevHash = HashValue;
325    }
326  }
327}
328
329void AppleAccelTableWriter::emitData() const {
330  const auto &Buckets = Contents.getBuckets();
331  for (size_t i = 0, e = Buckets.size(); i < e; ++i) {
332    uint64_t PrevHash = std::numeric_limits<uint64_t>::max();
333    for (auto &Hash : Buckets[i]) {
334      // Terminate the previous entry if there is no hash collision with the
335      // current one.
336      if (PrevHash != std::numeric_limits<uint64_t>::max() &&
337          PrevHash != Hash->HashValue)
338        Asm->emitInt32(0);
339      // Remember to emit the label for our offset.
340      Asm->OutStreamer->EmitLabel(Hash->Sym);
341      Asm->OutStreamer->AddComment(Hash->Name.getString());
342      Asm->emitDwarfStringOffset(Hash->Name);
343      Asm->OutStreamer->AddComment("Num DIEs");
344      Asm->emitInt32(Hash->Values.size());
345      for (const auto *V : Hash->Values)
346        static_cast<const AppleAccelTableData *>(V)->emit(Asm);
347      PrevHash = Hash->HashValue;
348    }
349    // Emit the final end marker for the bucket.
350    if (!Buckets[i].empty())
351      Asm->emitInt32(0);
352  }
353}
354
355void AppleAccelTableWriter::emit() const {
356  Header.emit(Asm);
357  HeaderData.emit(Asm);
358  emitBuckets();
359  emitHashes();
360  emitOffsets(SecBegin);
361  emitData();
362}
363
364template <typename DataT>
365void Dwarf5AccelTableWriter<DataT>::Header::emit(
366    const Dwarf5AccelTableWriter &Ctx) const {
367  assert(CompUnitCount > 0 && "Index must have at least one CU.");
368
369  AsmPrinter *Asm = Ctx.Asm;
370  Asm->OutStreamer->AddComment("Header: unit length");
371  Asm->EmitLabelDifference(Ctx.ContributionEnd, Ctx.ContributionStart,
372                           sizeof(uint32_t));
373  Asm->OutStreamer->EmitLabel(Ctx.ContributionStart);
374  Asm->OutStreamer->AddComment("Header: version");
375  Asm->emitInt16(Version);
376  Asm->OutStreamer->AddComment("Header: padding");
377  Asm->emitInt16(Padding);
378  Asm->OutStreamer->AddComment("Header: compilation unit count");
379  Asm->emitInt32(CompUnitCount);
380  Asm->OutStreamer->AddComment("Header: local type unit count");
381  Asm->emitInt32(LocalTypeUnitCount);
382  Asm->OutStreamer->AddComment("Header: foreign type unit count");
383  Asm->emitInt32(ForeignTypeUnitCount);
384  Asm->OutStreamer->AddComment("Header: bucket count");
385  Asm->emitInt32(BucketCount);
386  Asm->OutStreamer->AddComment("Header: name count");
387  Asm->emitInt32(NameCount);
388  Asm->OutStreamer->AddComment("Header: abbreviation table size");
389  Asm->EmitLabelDifference(Ctx.AbbrevEnd, Ctx.AbbrevStart, sizeof(uint32_t));
390  Asm->OutStreamer->AddComment("Header: augmentation string size");
391  assert(AugmentationStringSize % 4 == 0);
392  Asm->emitInt32(AugmentationStringSize);
393  Asm->OutStreamer->AddComment("Header: augmentation string");
394  Asm->OutStreamer->EmitBytes({AugmentationString, AugmentationStringSize});
395}
396
397template <typename DataT>
398DenseSet<uint32_t> Dwarf5AccelTableWriter<DataT>::getUniqueTags() const {
399  DenseSet<uint32_t> UniqueTags;
400  for (auto &Bucket : Contents.getBuckets()) {
401    for (auto *Hash : Bucket) {
402      for (auto *Value : Hash->Values) {
403        unsigned Tag = static_cast<const DataT *>(Value)->getDieTag();
404        UniqueTags.insert(Tag);
405      }
406    }
407  }
408  return UniqueTags;
409}
410
411template <typename DataT>
412SmallVector<typename Dwarf5AccelTableWriter<DataT>::AttributeEncoding, 2>
413Dwarf5AccelTableWriter<DataT>::getUniformAttributes() const {
414  SmallVector<AttributeEncoding, 2> UA;
415  if (CompUnits.size() > 1) {
416    size_t LargestCUIndex = CompUnits.size() - 1;
417    dwarf::Form Form = DIEInteger::BestForm(/*IsSigned*/ false, LargestCUIndex);
418    UA.push_back({dwarf::DW_IDX_compile_unit, Form});
419  }
420  UA.push_back({dwarf::DW_IDX_die_offset, dwarf::DW_FORM_ref4});
421  return UA;
422}
423
424template <typename DataT>
425void Dwarf5AccelTableWriter<DataT>::emitCUList() const {
426  for (const auto &CU : enumerate(CompUnits)) {
427    Asm->OutStreamer->AddComment("Compilation unit " + Twine(CU.index()));
428    Asm->emitDwarfSymbolReference(CU.value());
429  }
430}
431
432template <typename DataT>
433void Dwarf5AccelTableWriter<DataT>::emitBuckets() const {
434  uint32_t Index = 1;
435  for (const auto &Bucket : enumerate(Contents.getBuckets())) {
436    Asm->OutStreamer->AddComment("Bucket " + Twine(Bucket.index()));
437    Asm->emitInt32(Bucket.value().empty() ? 0 : Index);
438    Index += Bucket.value().size();
439  }
440}
441
442template <typename DataT>
443void Dwarf5AccelTableWriter<DataT>::emitStringOffsets() const {
444  for (const auto &Bucket : enumerate(Contents.getBuckets())) {
445    for (auto *Hash : Bucket.value()) {
446      DwarfStringPoolEntryRef String = Hash->Name;
447      Asm->OutStreamer->AddComment("String in Bucket " + Twine(Bucket.index()) +
448                                   ": " + String.getString());
449      Asm->emitDwarfStringOffset(String);
450    }
451  }
452}
453
454template <typename DataT>
455void Dwarf5AccelTableWriter<DataT>::emitAbbrevs() const {
456  Asm->OutStreamer->EmitLabel(AbbrevStart);
457  for (const auto &Abbrev : Abbreviations) {
458    Asm->OutStreamer->AddComment("Abbrev code");
459    assert(Abbrev.first != 0);
460    Asm->EmitULEB128(Abbrev.first);
461    Asm->OutStreamer->AddComment(dwarf::TagString(Abbrev.first));
462    Asm->EmitULEB128(Abbrev.first);
463    for (const auto &AttrEnc : Abbrev.second) {
464      Asm->EmitULEB128(AttrEnc.Index, dwarf::IndexString(AttrEnc.Index).data());
465      Asm->EmitULEB128(AttrEnc.Form,
466                       dwarf::FormEncodingString(AttrEnc.Form).data());
467    }
468    Asm->EmitULEB128(0, "End of abbrev");
469    Asm->EmitULEB128(0, "End of abbrev");
470  }
471  Asm->EmitULEB128(0, "End of abbrev list");
472  Asm->OutStreamer->EmitLabel(AbbrevEnd);
473}
474
475template <typename DataT>
476void Dwarf5AccelTableWriter<DataT>::emitEntry(const DataT &Entry) const {
477  auto AbbrevIt = Abbreviations.find(Entry.getDieTag());
478  assert(AbbrevIt != Abbreviations.end() &&
479         "Why wasn't this abbrev generated?");
480
481  Asm->EmitULEB128(AbbrevIt->first, "Abbreviation code");
482  for (const auto &AttrEnc : AbbrevIt->second) {
483    Asm->OutStreamer->AddComment(dwarf::IndexString(AttrEnc.Index));
484    switch (AttrEnc.Index) {
485    case dwarf::DW_IDX_compile_unit: {
486      DIEInteger ID(getCUIndexForEntry(Entry));
487      ID.EmitValue(Asm, AttrEnc.Form);
488      break;
489    }
490    case dwarf::DW_IDX_die_offset:
491      assert(AttrEnc.Form == dwarf::DW_FORM_ref4);
492      Asm->emitInt32(Entry.getDieOffset());
493      break;
494    default:
495      llvm_unreachable("Unexpected index attribute!");
496    }
497  }
498}
499
500template <typename DataT> void Dwarf5AccelTableWriter<DataT>::emitData() const {
501  Asm->OutStreamer->EmitLabel(EntryPool);
502  for (auto &Bucket : Contents.getBuckets()) {
503    for (auto *Hash : Bucket) {
504      // Remember to emit the label for our offset.
505      Asm->OutStreamer->EmitLabel(Hash->Sym);
506      for (const auto *Value : Hash->Values)
507        emitEntry(*static_cast<const DataT *>(Value));
508      Asm->OutStreamer->AddComment("End of list: " + Hash->Name.getString());
509      Asm->emitInt32(0);
510    }
511  }
512}
513
514template <typename DataT>
515Dwarf5AccelTableWriter<DataT>::Dwarf5AccelTableWriter(
516    AsmPrinter *Asm, const AccelTableBase &Contents,
517    ArrayRef<MCSymbol *> CompUnits,
518    llvm::function_ref<unsigned(const DataT &)> getCUIndexForEntry)
519    : AccelTableWriter(Asm, Contents, false),
520      Header(CompUnits.size(), Contents.getBucketCount(),
521             Contents.getUniqueNameCount()),
522      CompUnits(CompUnits), getCUIndexForEntry(std::move(getCUIndexForEntry)) {
523  DenseSet<uint32_t> UniqueTags = getUniqueTags();
524  SmallVector<AttributeEncoding, 2> UniformAttributes = getUniformAttributes();
525
526  Abbreviations.reserve(UniqueTags.size());
527  for (uint32_t Tag : UniqueTags)
528    Abbreviations.try_emplace(Tag, UniformAttributes);
529}
530
531template <typename DataT> void Dwarf5AccelTableWriter<DataT>::emit() const {
532  Header.emit(*this);
533  emitCUList();
534  emitBuckets();
535  emitHashes();
536  emitStringOffsets();
537  emitOffsets(EntryPool);
538  emitAbbrevs();
539  emitData();
540  Asm->OutStreamer->EmitValueToAlignment(4, 0);
541  Asm->OutStreamer->EmitLabel(ContributionEnd);
542}
543
544void llvm::emitAppleAccelTableImpl(AsmPrinter *Asm, AccelTableBase &Contents,
545                                   StringRef Prefix, const MCSymbol *SecBegin,
546                                   ArrayRef<AppleAccelTableData::Atom> Atoms) {
547  Contents.finalize(Asm, Prefix);
548  AppleAccelTableWriter(Asm, Contents, Atoms, SecBegin).emit();
549}
550
551void llvm::emitDWARF5AccelTable(
552    AsmPrinter *Asm, AccelTable<DWARF5AccelTableData> &Contents,
553    const DwarfDebug &DD, ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs) {
554  std::vector<MCSymbol *> CompUnits;
555  SmallVector<unsigned, 1> CUIndex(CUs.size());
556  int Count = 0;
557  for (const auto &CU : enumerate(CUs)) {
558    if (CU.value()->getCUNode()->getNameTableKind() !=
559        DICompileUnit::DebugNameTableKind::Default)
560      continue;
561    CUIndex[CU.index()] = Count++;
562    assert(CU.index() == CU.value()->getUniqueID());
563    const DwarfCompileUnit *MainCU =
564        DD.useSplitDwarf() ? CU.value()->getSkeleton() : CU.value().get();
565    CompUnits.push_back(MainCU->getLabelBegin());
566  }
567
568  if (CompUnits.empty())
569    return;
570
571  Asm->OutStreamer->SwitchSection(
572      Asm->getObjFileLowering().getDwarfDebugNamesSection());
573
574  Contents.finalize(Asm, "names");
575  Dwarf5AccelTableWriter<DWARF5AccelTableData>(
576      Asm, Contents, CompUnits,
577      [&](const DWARF5AccelTableData &Entry) {
578        const DIE *CUDie = Entry.getDie().getUnitDie();
579        return CUIndex[DD.lookupCU(CUDie)->getUniqueID()];
580      })
581      .emit();
582}
583
584void llvm::emitDWARF5AccelTable(
585    AsmPrinter *Asm, AccelTable<DWARF5AccelTableStaticData> &Contents,
586    ArrayRef<MCSymbol *> CUs,
587    llvm::function_ref<unsigned(const DWARF5AccelTableStaticData &)>
588        getCUIndexForEntry) {
589  Contents.finalize(Asm, "names");
590  Dwarf5AccelTableWriter<DWARF5AccelTableStaticData>(Asm, Contents, CUs,
591                                                     getCUIndexForEntry)
592      .emit();
593}
594
595void AppleAccelTableOffsetData::emit(AsmPrinter *Asm) const {
596  Asm->emitInt32(Die.getDebugSectionOffset());
597}
598
599void AppleAccelTableTypeData::emit(AsmPrinter *Asm) const {
600  Asm->emitInt32(Die.getDebugSectionOffset());
601  Asm->emitInt16(Die.getTag());
602  Asm->emitInt8(0);
603}
604
605void AppleAccelTableStaticOffsetData::emit(AsmPrinter *Asm) const {
606  Asm->emitInt32(Offset);
607}
608
609void AppleAccelTableStaticTypeData::emit(AsmPrinter *Asm) const {
610  Asm->emitInt32(Offset);
611  Asm->emitInt16(Tag);
612  Asm->emitInt8(ObjCClassIsImplementation ? dwarf::DW_FLAG_type_implementation
613                                          : 0);
614  Asm->emitInt32(QualifiedNameHash);
615}
616
617constexpr AppleAccelTableData::Atom AppleAccelTableTypeData::Atoms[];
618constexpr AppleAccelTableData::Atom AppleAccelTableOffsetData::Atoms[];
619constexpr AppleAccelTableData::Atom AppleAccelTableStaticOffsetData::Atoms[];
620constexpr AppleAccelTableData::Atom AppleAccelTableStaticTypeData::Atoms[];
621
622#ifndef NDEBUG
623void AppleAccelTableWriter::Header::print(raw_ostream &OS) const {
624  OS << "Magic: " << format("0x%x", Magic) << "\n"
625     << "Version: " << Version << "\n"
626     << "Hash Function: " << HashFunction << "\n"
627     << "Bucket Count: " << BucketCount << "\n"
628     << "Header Data Length: " << HeaderDataLength << "\n";
629}
630
631void AppleAccelTableData::Atom::print(raw_ostream &OS) const {
632  OS << "Type: " << dwarf::AtomTypeString(Type) << "\n"
633     << "Form: " << dwarf::FormEncodingString(Form) << "\n";
634}
635
636void AppleAccelTableWriter::HeaderData::print(raw_ostream &OS) const {
637  OS << "DIE Offset Base: " << DieOffsetBase << "\n";
638  for (auto Atom : Atoms)
639    Atom.print(OS);
640}
641
642void AppleAccelTableWriter::print(raw_ostream &OS) const {
643  Header.print(OS);
644  HeaderData.print(OS);
645  Contents.print(OS);
646  SecBegin->print(OS, nullptr);
647}
648
649void AccelTableBase::HashData::print(raw_ostream &OS) const {
650  OS << "Name: " << Name.getString() << "\n";
651  OS << "  Hash Value: " << format("0x%x", HashValue) << "\n";
652  OS << "  Symbol: ";
653  if (Sym)
654    OS << *Sym;
655  else
656    OS << "<none>";
657  OS << "\n";
658  for (auto *Value : Values)
659    Value->print(OS);
660}
661
662void AccelTableBase::print(raw_ostream &OS) const {
663  // Print Content.
664  OS << "Entries: \n";
665  for (const auto &Entry : Entries) {
666    OS << "Name: " << Entry.first() << "\n";
667    for (auto *V : Entry.second.Values)
668      V->print(OS);
669  }
670
671  OS << "Buckets and Hashes: \n";
672  for (auto &Bucket : Buckets)
673    for (auto &Hash : Bucket)
674      Hash->print(OS);
675
676  OS << "Data: \n";
677  for (auto &E : Entries)
678    E.second.print(OS);
679}
680
681void DWARF5AccelTableData::print(raw_ostream &OS) const {
682  OS << "  Offset: " << getDieOffset() << "\n";
683  OS << "  Tag: " << dwarf::TagString(getDieTag()) << "\n";
684}
685
686void DWARF5AccelTableStaticData::print(raw_ostream &OS) const {
687  OS << "  Offset: " << getDieOffset() << "\n";
688  OS << "  Tag: " << dwarf::TagString(getDieTag()) << "\n";
689}
690
691void AppleAccelTableOffsetData::print(raw_ostream &OS) const {
692  OS << "  Offset: " << Die.getOffset() << "\n";
693}
694
695void AppleAccelTableTypeData::print(raw_ostream &OS) const {
696  OS << "  Offset: " << Die.getOffset() << "\n";
697  OS << "  Tag: " << dwarf::TagString(Die.getTag()) << "\n";
698}
699
700void AppleAccelTableStaticOffsetData::print(raw_ostream &OS) const {
701  OS << "  Static Offset: " << Offset << "\n";
702}
703
704void AppleAccelTableStaticTypeData::print(raw_ostream &OS) const {
705  OS << "  Static Offset: " << Offset << "\n";
706  OS << "  QualifiedNameHash: " << format("%x\n", QualifiedNameHash) << "\n";
707  OS << "  Tag: " << dwarf::TagString(Tag) << "\n";
708  OS << "  ObjCClassIsImplementation: "
709     << (ObjCClassIsImplementation ? "true" : "false");
710  OS << "\n";
711}
712#endif
713