llvm · dzhidzhoev · Sep 23, 2025 · Sep 23, 2025
diff --git a/llvm/include/llvm/CodeGen/DebugHandlerBase.h b/llvm/include/llvm/CodeGen/DebugHandlerBase.h
@@ -144,8 +144,6 @@ class DebugHandlerBase : public AsmPrinterHandler {
   static bool isUnsignedDIType(const DIType *Ty);
 
   const InstructionOrdering &getInstOrdering() const { return InstOrdering; }
-
-  const LexicalScopes &getLexicalScopes() const { return LScopes; }
 };
 
 } // namespace llvm

diff --git a/llvm/include/llvm/CodeGen/LexicalScopes.h b/llvm/include/llvm/CodeGen/LexicalScopes.h
@@ -141,18 +141,12 @@ class LexicalScopes {
 public:
   LexicalScopes() = default;
 
-  /// Scan module to build subprogram-to-function map.
-  LLVM_ABI void initialize(const Module &);
-
   /// Scan machine function and constuct lexical scope nest, resets
   /// the instance if necessary.
-  LLVM_ABI void scanFunction(const MachineFunction &);
-
-  /// Reset the instance so that it's prepared for another module.
-  LLVM_ABI void resetModule();
+  LLVM_ABI void initialize(const MachineFunction &);
 
-  /// Reset the instance so that it's prepared for another function.
-  LLVM_ABI void resetFunction();
+  /// Release memory.
+  LLVM_ABI void reset();
 
   /// Return true if there is any lexical scope information available.
   bool empty() { return CurrentFnLexicalScope == nullptr; }
@@ -202,11 +196,6 @@ class LexicalScopes {
   /// Find or create an abstract lexical scope.
   LLVM_ABI LexicalScope *getOrCreateAbstractScope(const DILocalScope *Scope);
 
-  /// Get function to which the given subprogram is attached, if exists.
-  const Function *getFunction(const DISubprogram *SP) const {
-    return FunctionMap.lookup(SP);
-  }
-
 private:
   /// Find lexical scope for the given Scope/IA. If not available
   /// then create new lexical scope.
@@ -236,9 +225,6 @@ class LexicalScopes {
 
   const MachineFunction *MF = nullptr;
 
-  /// Mapping between DISubprograms and IR functions.
-  DenseMap<const DISubprogram *, const Function *> FunctionMap;
-
   /// Tracks the scopes in the current function.
   // Use an unordered_map to ensure value pointer validity over insertion.
   std::unordered_map<const DILocalScope *, LexicalScope> LexicalScopeMap;

diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -105,8 +105,6 @@ DebugHandlerBase::~DebugHandlerBase() = default;
 void DebugHandlerBase::beginModule(Module *M) {
   if (M->debug_compile_units().empty())
     Asm = nullptr;
-  else
-    LScopes.initialize(*M);
 }
 
 // Each LexicalScope has first instruction and last instruction to mark
@@ -271,7 +269,7 @@ void DebugHandlerBase::beginFunction(const MachineFunction *MF) {
 
   // Grab the lexical scopes for the function, if we don't have any of those
   // then we're not going to be able to do anything.
-  LScopes.scanFunction(*MF);
+  LScopes.initialize(*MF);
   if (LScopes.empty()) {
     beginFunctionImpl(MF);
     return;

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -537,9 +537,8 @@ void DwarfCompileUnit::addWasmRelocBaseGlobal(DIELoc *Loc, StringRef GlobalName,
 // and DW_AT_high_pc attributes. If there are global variables in this
 // scope then create and insert DIEs for these variables.
 DIE &DwarfCompileUnit::updateSubprogramScopeDIE(const DISubprogram *SP,
-                                                const Function &F,
                                                 MCSymbol *LineTableSym) {
-  DIE *SPDie = getOrCreateSubprogramDIE(SP, &F, includeMinimalInlineScopes());
+  DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
   SmallVector<RangeSpan, 2> BB_List;
   // If basic block sections are on, ranges for each basic block section has
   // to be emitted separately.
@@ -1123,10 +1122,9 @@ sortLocalVars(SmallVectorImpl<DbgVariable *> &Input) {
 }
 
 DIE &DwarfCompileUnit::constructSubprogramScopeDIE(const DISubprogram *Sub,
-                                                   const Function &F,
                                                    LexicalScope *Scope,
                                                    MCSymbol *LineTableSym) {
-  DIE &ScopeDIE = updateSubprogramScopeDIE(Sub, F, LineTableSym);
+  DIE &ScopeDIE = updateSubprogramScopeDIE(Sub, LineTableSym);
 
   if (Scope) {
     assert(!Scope->getInlinedAt());
@@ -1200,17 +1198,32 @@ DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
   return ObjectPointer;
 }
 
-DIE &DwarfCompileUnit::getOrCreateAbstractSubprogramDIE(
-    const DISubprogram *SP) {
-  if (auto *AbsDef = getAbstractScopeDIEs().lookup(SP))
-    return *AbsDef;
+void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
+    LexicalScope *Scope) {
+  auto *SP = cast<DISubprogram>(Scope->getScopeNode());
+  if (getAbstractScopeDIEs().count(SP))
+    return;
 
-  auto [ContextDIE, ContextCU] = getOrCreateAbstractSubprogramContextDIE(SP);
-  return createAbstractSubprogramDIE(SP, ContextDIE, ContextCU);
-}
+  DIE *ContextDIE;
+  DwarfCompileUnit *ContextCU = this;
+
+  if (includeMinimalInlineScopes())
+    ContextDIE = &getUnitDie();
+  // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
+  // the important distinction that the debug node is not associated with the
+  // DIE (since the debug node will be associated with the concrete DIE, if
+  // any). It could be refactored to some common utility function.
+  else if (auto *SPDecl = SP->getDeclaration()) {
+    ContextDIE = &getUnitDie();
+    getOrCreateSubprogramDIE(SPDecl);
+  } else {
+    ContextDIE = getOrCreateContextDIE(SP->getScope());
+    // The scope may be shared with a subprogram that has already been
+    // constructed in another CU, in which case we need to construct this
+    // subprogram in the same CU.
+    ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
+  }
 
-DIE &DwarfCompileUnit::createAbstractSubprogramDIE(
-    const DISubprogram *SP, DIE *ContextDIE, DwarfCompileUnit *ContextCU) {
   // Passing null as the associated node because the abstract definition
   // shouldn't be found by lookup.
   DIE &AbsDef = ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram,
@@ -1224,45 +1237,8 @@ DIE &DwarfCompileUnit::createAbstractSubprogramDIE(
                      DD->getDwarfVersion() <= 4 ? std::optional<dwarf::Form>()
                                                 : dwarf::DW_FORM_implicit_const,
                      dwarf::DW_INL_inlined);
-
-  return AbsDef;
-}
-
-std::pair<DIE *, DwarfCompileUnit *>
-DwarfCompileUnit::getOrCreateAbstractSubprogramContextDIE(
-    const DISubprogram *SP) {
-  bool Minimal = includeMinimalInlineScopes();
-  bool IgnoreScope = shouldPlaceInUnitDIE(SP, Minimal);
-  DIE *ContextDIE = getOrCreateSubprogramContextDIE(SP, IgnoreScope);
-
-  if (auto *SPDecl = SP->getDeclaration())
-    if (!Minimal)
-      getOrCreateSubprogramDIE(SPDecl, nullptr);
-
-  // The scope may be shared with a subprogram that has already been
-  // constructed in another CU, in which case we need to construct this
-  // subprogram in the same CU.
-  auto *ContextCU = IgnoreScope ? this : DD->lookupCU(ContextDIE->getUnitDie());
-
-  return std::make_pair(ContextDIE, ContextCU);
-}
-
-void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
-    LexicalScope *Scope) {
-  auto *SP = cast<DISubprogram>(Scope->getScopeNode());
-
-  // Populate subprogram DIE only once.
-  if (!getFinalizedAbstractSubprograms().insert(SP).second)
-    return;
-
-  auto [ContextDIE, ContextCU] = getOrCreateAbstractSubprogramContextDIE(SP);
-  DIE *AbsDef = getAbstractScopeDIEs().lookup(SP);
-  if (!AbsDef)
-    AbsDef = &createAbstractSubprogramDIE(SP, ContextDIE, ContextCU);
-
-  if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
-    ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer,
-                           *ObjectPointer);
+  if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, AbsDef))
+    ContextCU->addDIEEntry(AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 }
 
 bool DwarfCompileUnit::useGNUAnalogForDwarf5Feature() const {
@@ -1317,9 +1293,9 @@ DwarfCompileUnit::getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const {
 }
 
 DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
-    DIE &ScopeDIE, const DISubprogram *CalleeSP, const Function *CalleeF,
-    bool IsTail, const MCSymbol *PCAddr, const MCSymbol *CallAddr,
-    unsigned CallReg, DIType *AllocSiteTy) {
+    DIE &ScopeDIE, const DISubprogram *CalleeSP, bool IsTail,
+    const MCSymbol *PCAddr, const MCSymbol *CallAddr, unsigned CallReg,
+    DIType *AllocSiteTy) {
   // Insert a call site entry DIE within ScopeDIE.
   DIE &CallSiteDIE = createAndAddDIE(getDwarf5OrGNUTag(dwarf::DW_TAG_call_site),
                                      ScopeDIE, nullptr);
@@ -1329,7 +1305,7 @@ DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
     addAddress(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_target),
                MachineLocation(CallReg));
   } else if (CalleeSP) {
-    DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP, CalleeF);
+    DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP);
     assert(CalleeDIE && "Could not create DIE for call site entry origin");
     if (AddLinkageNamesToDeclCallOriginsForTuning(DD) &&
         !CalleeSP->isDefinition() &&
@@ -1420,7 +1396,7 @@ DIE *DwarfCompileUnit::constructImportedEntityDIE(
     if (auto *AbsSPDie = getAbstractScopeDIEs().lookup(SP))
       EntityDie = AbsSPDie;
     else
-      EntityDie = getOrCreateSubprogramDIE(SP, nullptr);
+      EntityDie = getOrCreateSubprogramDIE(SP);
   } else if (auto *T = dyn_cast<DIType>(Entity))
     EntityDie = getOrCreateTypeDIE(T);
   else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
@@ -1829,16 +1805,3 @@ DIE *DwarfCompileUnit::getOrCreateContextDIE(const DIScope *Context) {
   }
   return DwarfUnit::getOrCreateContextDIE(Context);
 }
-
-DIE *DwarfCompileUnit::getOrCreateSubprogramDIE(const DISubprogram *SP,
-                                                const Function *F,
-                                                bool Minimal) {
-  if (!F && SP->isDefinition()) {
-    F = DD->getLexicalScopes().getFunction(SP);
-
-    if (!F)
-      return &getCU().getOrCreateAbstractSubprogramDIE(SP);
-  }
-
-  return DwarfUnit::getOrCreateSubprogramDIE(SP, F, Minimal);
-}
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -81,7 +81,6 @@ class DwarfCompileUnit final : public DwarfUnit {
 
   // List of abstract local scopes (either DISubprogram or DILexicalBlock).
   DenseMap<const DILocalScope *, DIE *> AbstractLocalScopeDIEs;
-  SmallPtrSet<const DISubprogram *, 8> FinalizedAbstractSubprograms;
 
   // List of inlined lexical block scopes that belong to subprograms within this
   // CU.
@@ -138,28 +137,12 @@ class DwarfCompileUnit final : public DwarfUnit {
     return DU->getAbstractEntities();
   }
 
-  auto &getFinalizedAbstractSubprograms() {
-    if (isDwoUnit() && !DD->shareAcrossDWOCUs())
-      return FinalizedAbstractSubprograms;
-    return DU->getFinalizedAbstractSubprograms();
-  }
-
   void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
 
   /// Add info for Wasm-global-based relocation.
   void addWasmRelocBaseGlobal(DIELoc *Loc, StringRef GlobalName,
                               uint64_t GlobalIndex);
 
-  /// Create context DIE for abstract subprogram.
-  /// \returns The context DIE and the compile unit where abstract
-  ///          DIE should be constructed.
-  std::pair<DIE *, DwarfCompileUnit *>
-  getOrCreateAbstractSubprogramContextDIE(const DISubprogram *SP);
-
-  /// Create new DIE for abstract subprogram.
-  DIE &createAbstractSubprogramDIE(const DISubprogram *SP, DIE *ContextDIE,
-                                   DwarfCompileUnit *ContextCU);
-
 public:
   DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
                    DwarfDebug *DW, DwarfFile *DWU,
@@ -233,8 +216,7 @@ class DwarfCompileUnit final : public DwarfUnit {
   /// DW_AT_low_pc, DW_AT_high_pc and DW_AT_LLVM_stmt_sequence attributes.
   /// If there are global variables in this scope then create and insert DIEs
   /// for these variables.
-  DIE &updateSubprogramScopeDIE(const DISubprogram *SP, const Function &F,
-                                MCSymbol *LineTableSym);
+  DIE &updateSubprogramScopeDIE(const DISubprogram *SP, MCSymbol *LineTableSym);
 
   void constructScopeDIE(LexicalScope *Scope, DIE &ParentScopeDIE);
 
@@ -277,18 +259,12 @@ class DwarfCompileUnit final : public DwarfUnit {
   /// This instance of 'getOrCreateContextDIE()' can handle DILocalScope.
   DIE *getOrCreateContextDIE(const DIScope *Ty) override;
 
-  DIE *getOrCreateSubprogramDIE(const DISubprogram *SP, const Function *F,
-                                bool Minimal = false) override;
-
   /// Construct a DIE for this subprogram scope.
-  DIE &constructSubprogramScopeDIE(const DISubprogram *Sub, const Function &F,
-                                   LexicalScope *Scope, MCSymbol *LineTableSym);
+  DIE &constructSubprogramScopeDIE(const DISubprogram *Sub, LexicalScope *Scope,
+                                   MCSymbol *LineTableSym);
 
   DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
 
-  /// Create an abstract subprogram DIE, that should later be populated
-  /// by \ref constructAbstractSubprogramScopeDIE.
-  DIE &getOrCreateAbstractSubprogramDIE(const DISubprogram *SP);
   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 
   /// Whether to use the GNU analog for a DWARF5 tag, attribute, or location
@@ -305,15 +281,14 @@ class DwarfCompileUnit final : public DwarfUnit {
   dwarf::LocationAtom getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const;
 
   /// Construct a call site entry DIE describing a call within \p Scope to a
-  /// callee described by \p CalleeSP and \p CalleeF.
+  /// callee described by \p CalleeSP.
   /// \p IsTail specifies whether the call is a tail call.
   /// \p PCAddr points to the PC value after the call instruction.
   /// \p CallAddr points to the PC value at the call instruction (or is null).
   /// \p CallReg is a register location for an indirect call. For direct calls
   /// the \p CallReg is set to 0.
   DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
-                                 const Function *CalleeF, bool IsTail,
-                                 const MCSymbol *PCAddr,
+                                 bool IsTail, const MCSymbol *PCAddr,
                                  const MCSymbol *CallAddr, unsigned CallReg,
                                  DIType *AllocSiteTy);
   /// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -997,9 +997,8 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
                                                        ->getName(CallReg)))
                         << (IsTail ? " [IsTail]" : "") << "\n");
 
-      DIE &CallSiteDIE =
-          CU.constructCallSiteEntryDIE(ScopeDIE, CalleeSP, CalleeDecl, IsTail,
-                                       PCAddr, CallAddr, CallReg, AllocSiteTy);
+      DIE &CallSiteDIE = CU.constructCallSiteEntryDIE(
+          ScopeDIE, CalleeSP, IsTail, PCAddr, CallAddr, CallReg, AllocSiteTy);
 
       // Optionally emit call-site-param debug info.
       if (emitDebugEntryValues()) {
@@ -2708,8 +2707,7 @@ void DwarfDebug::skippedNonDebugFunction() {
 
 // Gather and emit post-function debug information.
 void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
-  const Function &F = MF->getFunction();
-  const DISubprogram *SP = F.getSubprogram();
+  const DISubprogram *SP = MF->getFunction().getSubprogram();
 
   assert(CurFn == MF &&
       "endFunction should be called with the same function as beginFunction");
@@ -2778,12 +2776,11 @@ void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
 
   ProcessedSPNodes.insert(SP);
   DIE &ScopeDIE =
-      TheCU.constructSubprogramScopeDIE(SP, F, FnScope, FunctionLineTableLabel);
+      TheCU.constructSubprogramScopeDIE(SP, FnScope, FunctionLineTableLabel);
   if (auto *SkelCU = TheCU.getSkeleton())
     if (!LScopes.getAbstractScopesList().empty() &&
         TheCU.getCUNode()->getSplitDebugInlining())
-      SkelCU->constructSubprogramScopeDIE(SP, F, FnScope,
-                                          FunctionLineTableLabel);
+      SkelCU->constructSubprogramScopeDIE(SP, FnScope, FunctionLineTableLabel);
 
   FunctionLineTableLabel = nullptr;
 

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
@@ -11,7 +11,6 @@
 
 #include "DwarfStringPool.h"
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/CodeGen/DIE.h"
@@ -28,7 +27,6 @@ class DbgVariable;
 class DbgLabel;
 class DINode;
 class DILocalScope;
-class DISubprogram;
 class DwarfCompileUnit;
 class DwarfUnit;
 class LexicalScope;
@@ -96,9 +94,6 @@ class DwarfFile {
   // Collection of abstract subprogram DIEs.
   DenseMap<const DILocalScope *, DIE *> AbstractLocalScopeDIEs;
   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
-  /// Keeps track of abstract subprograms to populate them only once.
-  // FIXME: merge creation and population of abstract scopes.
-  SmallPtrSet<const DISubprogram *, 8> FinalizedAbstractSubprograms;
 
   /// Maps MDNodes for type system with the corresponding DIEs. These DIEs can
   /// be shared across CUs, that is why we keep the map here instead
@@ -179,10 +174,6 @@ class DwarfFile {
     return AbstractEntities;
   }
 
-  auto &getFinalizedAbstractSubprograms() {
-    return FinalizedAbstractSubprograms;
-  }
-
   void insertDIE(const MDNode *TypeMD, DIE *Die) {
     DITypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));
   }