[LLVM[NFC] Refactor to allow debug_names entries to conatain DIE offset

llvm/include/llvm/CodeGen/AccelTable.h

@@ -252,44 +252,38 @@ class DWARF5AccelTableData : public AccelTableData {
 public:
   static uint32_t hash(StringRef Name) { return caseFoldingDjbHash(Name); }
 
-  DWARF5AccelTableData(const DIE &Die) : Die(Die) {}
+  DWARF5AccelTableData(const DIE &Die, const DwarfCompileUnit &CU);
+  DWARF5AccelTableData(uint64_t DieOffset, unsigned DieTag, unsigned CUIndex)
+      : OffsetVal(DieOffset), DieTag(DieTag), UnitID(CUIndex) {}
 
 #ifndef NDEBUG
   void print(raw_ostream &OS) const override;
 #endif
 
-  const DIE &getDie() const { return Die; }
-  uint64_t getDieOffset() const { return Die.getOffset(); }
-  unsigned getDieTag() const { return Die.getTag(); }
+  uint64_t getDieOffset() const {
+    assert(std::holds_alternative<uint64_t>(OffsetVal) &&
+           "Accessing DIE Offset before normalizing.");
+    return std::get<uint64_t>(OffsetVal);
+  }
+  unsigned getDieTag() const { return DieTag; }
+  unsigned getUnitID() const { return UnitID; }
+  void normalizeDIEToOffset() {
+    assert(std::holds_alternative<const DIE *>(OffsetVal) &&
+           "Accessing offset after normalizing.");
+    OffsetVal = std::get<const DIE *>(OffsetVal)->getOffset();
+  }
 
 protected:
-  const DIE &Die;
+  std::variant<const DIE *, uint64_t> OffsetVal;
+  unsigned DieTag;
+  unsigned UnitID;
 
-  uint64_t order() const override { return Die.getOffset(); }
+  uint64_t order() const override { return getDieOffset(); }
 };
 
-class DWARF5AccelTableStaticData : public AccelTableData {
+class DWARF5AccelTable : public AccelTable<DWARF5AccelTableData> {
 public:
-  static uint32_t hash(StringRef Name) { return caseFoldingDjbHash(Name); }
-
-  DWARF5AccelTableStaticData(uint64_t DieOffset, unsigned DieTag,
-                             unsigned CUIndex)
-      : DieOffset(DieOffset), DieTag(DieTag), CUIndex(CUIndex) {}
-
-#ifndef NDEBUG
-  void print(raw_ostream &OS) const override;
-#endif
-
-  uint64_t getDieOffset() const { return DieOffset; }
-  unsigned getDieTag() const { return DieTag; }
-  unsigned getCUIndex() const { return CUIndex; }
-
-protected:
-  uint64_t DieOffset;
-  unsigned DieTag;
-  unsigned CUIndex;
-
-  uint64_t order() const override { return DieOffset; }
+  StringEntries &getEntries() { return Entries; }
 };
 
 void emitAppleAccelTableImpl(AsmPrinter *Asm, AccelTableBase &Contents,
@@ -306,8 +300,7 @@ void emitAppleAccelTable(AsmPrinter *Asm, AccelTable<DataT> &Contents,
   emitAppleAccelTableImpl(Asm, Contents, Prefix, SecBegin, DataT::Atoms);
 }
 
-void emitDWARF5AccelTable(AsmPrinter *Asm,
-                          AccelTable<DWARF5AccelTableData> &Contents,
+void emitDWARF5AccelTable(AsmPrinter *Asm, DWARF5AccelTable &Contents,
                           const DwarfDebug &DD,
                           ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs);
 
@@ -316,9 +309,9 @@ void emitDWARF5AccelTable(AsmPrinter *Asm,
 /// start of compilation unit, either offsets to the start of compilation
 /// unit themselves.
 void emitDWARF5AccelTable(
-    AsmPrinter *Asm, AccelTable<DWARF5AccelTableStaticData> &Contents,
+    AsmPrinter *Asm, DWARF5AccelTable &Contents,
     ArrayRef<std::variant<MCSymbol *, uint64_t>> CUs,
-    llvm::function_ref<unsigned(const DWARF5AccelTableStaticData &)>
+    llvm::function_ref<unsigned(const DWARF5AccelTableData &)>
         getCUIndexForEntry);
 
 /// Accelerator table data implementation for simple Apple accelerator tables

llvm/include/llvm/DWARFLinker/DWARFLinker.h

@@ -119,8 +119,7 @@ class DwarfEmitter {
   virtual void emitLineStrings(const NonRelocatableStringpool &Pool) = 0;
 
   /// Emit DWARF debug names.
-  virtual void
-  emitDebugNames(AccelTable<DWARF5AccelTableStaticData> &Table) = 0;
+  virtual void emitDebugNames(DWARF5AccelTable &Table) = 0;
 
   /// Emit Apple namespaces accelerator table.
   virtual void
@@ -880,7 +879,7 @@ class DWARFLinker {
   uint32_t LastCIEOffset = 0;
 
   /// Apple accelerator tables.
-  AccelTable<DWARF5AccelTableStaticData> DebugNames;
+  DWARF5AccelTable DebugNames;
   AccelTable<AppleAccelTableStaticOffsetData> AppleNames;
   AccelTable<AppleAccelTableStaticOffsetData> AppleNamespaces;
   AccelTable<AppleAccelTableStaticOffsetData> AppleObjc;

llvm/include/llvm/DWARFLinker/DWARFStreamer.h

@@ -163,7 +163,7 @@ class DwarfStreamer : public DwarfEmitter {
                StringRef Bytes) override;
 
   /// Emit DWARF debug names.
-  void emitDebugNames(AccelTable<DWARF5AccelTableStaticData> &Table) override;
+  void emitDebugNames(DWARF5AccelTable &Table) override;
 
   /// Emit Apple namespaces accelerator table.
   void emitAppleNamespaces(

llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp

@@ -357,6 +357,13 @@ void AppleAccelTableWriter::emit() const {
   emitData();
 }
 
+DWARF5AccelTableData::DWARF5AccelTableData(const DIE &Die,
+                                           const DwarfCompileUnit &CU)
+    : OffsetVal(&Die) {
+  DieTag = Die.getTag();
+  UnitID = CU.getUniqueID();
+}
+
 template <typename DataT>
 void Dwarf5AccelTableWriter<DataT>::Header::emit(Dwarf5AccelTableWriter &Ctx) {
   assert(CompUnitCount > 0 && "Index must have at least one CU.");
@@ -545,8 +552,8 @@ void llvm::emitAppleAccelTableImpl(AsmPrinter *Asm, AccelTableBase &Contents,
 }
 
 void llvm::emitDWARF5AccelTable(
-    AsmPrinter *Asm, AccelTable<DWARF5AccelTableData> &Contents,
-    const DwarfDebug &DD, ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs) {
+    AsmPrinter *Asm, DWARF5AccelTable &Contents, const DwarfDebug &DD,
+    ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs) {
   std::vector<std::variant<MCSymbol *, uint64_t>> CompUnits;
   SmallVector<unsigned, 1> CUIndex(CUs.size());
   int Count = 0;
@@ -575,20 +582,19 @@ void llvm::emitDWARF5AccelTable(
   Dwarf5AccelTableWriter<DWARF5AccelTableData>(
       Asm, Contents, CompUnits,
       [&](const DWARF5AccelTableData &Entry) {
-        const DIE *CUDie = Entry.getDie().getUnitDie();
-        return CUIndex[DD.lookupCU(CUDie)->getUniqueID()];
+        return CUIndex[Entry.getUnitID()];
       })
       .emit();
 }
 
 void llvm::emitDWARF5AccelTable(
-    AsmPrinter *Asm, AccelTable<DWARF5AccelTableStaticData> &Contents,
+    AsmPrinter *Asm, DWARF5AccelTable &Contents,
     ArrayRef<std::variant<MCSymbol *, uint64_t>> CUs,
-    llvm::function_ref<unsigned(const DWARF5AccelTableStaticData &)>
+    llvm::function_ref<unsigned(const DWARF5AccelTableData &)>
         getCUIndexForEntry) {
   Contents.finalize(Asm, "names");
-  Dwarf5AccelTableWriter<DWARF5AccelTableStaticData>(Asm, Contents, CUs,
-                                                     getCUIndexForEntry)
+  Dwarf5AccelTableWriter<DWARF5AccelTableData>(Asm, Contents, CUs,
+                                               getCUIndexForEntry)
       .emit();
 }
 
@@ -687,11 +693,6 @@ void DWARF5AccelTableData::print(raw_ostream &OS) const {
   OS << "  Tag: " << dwarf::TagString(getDieTag()) << "\n";
 }
 
-void DWARF5AccelTableStaticData::print(raw_ostream &OS) const {
-  OS << "  Offset: " << getDieOffset() << "\n";
-  OS << "  Tag: " << dwarf::TagString(getDieTag()) << "\n";
-}
-
 void AppleAccelTableOffsetData::print(raw_ostream &OS) const {
   OS << "  Offset: " << Die.getOffset() << "\n";
 }

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -1246,6 +1246,17 @@ void DwarfDebug::finishSubprogramDefinitions() {
   }
 }
 
+/// Finalizes DWARF acceleration tables.
+/// Currently it converts DIE entries to offsets in .debu_names entry.
+static void
+finalizeDWARF5AccelerationTables(DWARF5AccelTable &AccelDebugNames) {
+  for (auto &Entry : AccelDebugNames.getEntries()) {
+    for (AccelTableData *Value : Entry.second.Values) {
+      static_cast<DWARF5AccelTableData *>(Value)->normalizeDIEToOffset();
+    }
+  }
+}
+
 void DwarfDebug::finalizeModuleInfo() {
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
 
@@ -1389,6 +1400,10 @@ void DwarfDebug::finalizeModuleInfo() {
   InfoHolder.computeSizeAndOffsets();
   if (useSplitDwarf())
     SkeletonHolder.computeSizeAndOffsets();
+
+  // Now that offsets are computed, can replace DIEs in debug_names Entry with
+  // an actual offset.
+  finalizeDWARF5AccelerationTables(AccelDebugNames);
 }
 
 // Emit all Dwarf sections that should come after the content.
@@ -3547,9 +3562,11 @@ void DwarfDebug::addAccelNameImpl(const DICompileUnit &CU,
   case AccelTableKind::Apple:
     AppleAccel.addName(Ref, Die);
     break;
-  case AccelTableKind::Dwarf:
-    AccelDebugNames.addName(Ref, Die);
+  case AccelTableKind::Dwarf: {
+    DwarfCompileUnit *CU = lookupCU(Die.getUnitDie());
+    AccelDebugNames.addName(Ref, Die, *CU);
     break;
+  }
   case AccelTableKind::Default:
     llvm_unreachable("Default should have already been resolved.");
   case AccelTableKind::None:

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -496,7 +496,7 @@ class DwarfDebug : public DebugHandlerBase {
   AddressPool AddrPool;
 
   /// Accelerator tables.
-  AccelTable<DWARF5AccelTableData> AccelDebugNames;
+  DWARF5AccelTable AccelDebugNames;
   AccelTable<AppleAccelTableOffsetData> AccelNames;
   AccelTable<AppleAccelTableOffsetData> AccelObjC;
   AccelTable<AppleAccelTableOffsetData> AccelNamespace;

llvm/lib/DWARFLinker/DWARFStreamer.cpp

@@ -291,8 +291,7 @@ void DwarfStreamer::emitLineStrings(const NonRelocatableStringpool &Pool) {
   }
 }
 
-void DwarfStreamer::emitDebugNames(
-    AccelTable<DWARF5AccelTableStaticData> &Table) {
+void DwarfStreamer::emitDebugNames(DWARF5AccelTable &Table) {
   if (EmittedUnits.empty())
     return;
 
@@ -307,11 +306,10 @@ void DwarfStreamer::emitDebugNames(
   }
 
   Asm->OutStreamer->switchSection(MOFI->getDwarfDebugNamesSection());
-  emitDWARF5AccelTable(
-      Asm.get(), Table, CompUnits,
-      [&UniqueIdToCuMap](const DWARF5AccelTableStaticData &Entry) {
-        return UniqueIdToCuMap[Entry.getCUIndex()];
-      });
+  emitDWARF5AccelTable(Asm.get(), Table, CompUnits,
+                       [&UniqueIdToCuMap](const DWARF5AccelTableData &Entry) {
+                         return UniqueIdToCuMap[Entry.getUnitID()];
+                       });
 }
 
 void DwarfStreamer::emitAppleNamespaces(

llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp

@@ -223,16 +223,16 @@ void DwarfEmitterImpl::emitDIE(DIE &Die) {
   DebugInfoSectionSize += Die.getSize();
 }
 
-void DwarfEmitterImpl::emitDebugNames(
-    AccelTable<DWARF5AccelTableStaticData> &Table,
-    DebugNamesUnitsOffsets &CUOffsets, CompUnitIDToIdx &CUidToIdx) {
+void DwarfEmitterImpl::emitDebugNames(DWARF5AccelTable &Table,
+                                      DebugNamesUnitsOffsets &CUOffsets,
+                                      CompUnitIDToIdx &CUidToIdx) {
   if (CUOffsets.empty())
     return;
 
   Asm->OutStreamer->switchSection(MOFI->getDwarfDebugNamesSection());
   emitDWARF5AccelTable(Asm.get(), Table, CUOffsets,
-                       [&CUidToIdx](const DWARF5AccelTableStaticData &Entry) {
-                         return CUidToIdx[Entry.getCUIndex()];
+                       [&CUidToIdx](const DWARF5AccelTableData &Entry) {
+                         return CUidToIdx[Entry.getUnitID()];
                        });
 }
 

llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h

@@ -87,7 +87,7 @@ class DwarfEmitterImpl : public ExtraDwarfEmitter {
   uint64_t getDebugInfoSectionSize() const { return DebugInfoSectionSize; }
 
   /// Emits .debug_names section according to the specified \p Table.
-  void emitDebugNames(AccelTable<DWARF5AccelTableStaticData> &Table,
+  void emitDebugNames(DWARF5AccelTable &Table,
                       DebugNamesUnitsOffsets &CUOffsets,
                       CompUnitIDToIdx &UnitIDToIdxMap);
 

llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp

@@ -1129,7 +1129,7 @@ void DWARFLinkerImpl::emitAppleAcceleratorSections(const Triple &TargetTriple) {
 }
 
 void DWARFLinkerImpl::emitDWARFv5DebugNamesSection(const Triple &TargetTriple) {
-  std::unique_ptr<AccelTable<DWARF5AccelTableStaticData>> DebugNames;
+  std::unique_ptr<DWARF5AccelTable> DebugNames;
 
   DebugNamesUnitsOffsets CompUnits;
   CompUnitIDToIdx CUidToIdx;
@@ -1144,7 +1144,7 @@ void DWARFLinkerImpl::emitDWARFv5DebugNamesSection(const Triple &TargetTriple) {
 
     CU->AcceleratorRecords.forEach([&](const DwarfUnit::AccelInfo &Info) {
       if (DebugNames.get() == nullptr)
-        DebugNames = std::make_unique<AccelTable<DWARF5AccelTableStaticData>>();
+        DebugNames = std::make_unique<DWARF5AccelTable>();
 
       switch (Info.Type) {
       case DwarfUnit::AccelType::Name: