[DebugMetadata][DwarfDebug] Fix DWARF emisson of function-local imported entities (3/7)

[dzhidzhoev]

Summary

RFC https://discourse.llvm.org/t/rfc-dwarfdebug-fix-and-improve-handling-imported-entities-types-and-static-local-in-subprogram-and-lexical-block-scopes/68544

Fixed PR51501 (tests from D112337).

This patch proposes two changes that get squashed to this single patch due to
their close dependencies:

1. Reuse of DISubprogram's 'retainedNodes' to track other function-local entities together with local variables and labels (this patch cares about function-local import while D144006 and D144008 use the same approach for local types and static variables). So, effectively this patch moves ownership of tracking local import from DICompileUnit's 'imports' field to DISubprogram's 'retainedNodes' and adjusts DWARF emitter for the new layout. The old layout is considered unsupported (DwarfDebug would assert on such debug metadata).
   
   DICompileUnit's 'imports' field is supposed to track global imported declarations as it does before.
   
   This addresses various FIXMEs and simplifies the next part of the patch.

2. Postpone emission of function-local imported entities from DwarfDebug::endFunctionImpl() to DwarfDebug::endModule(). While in DwarfDebug::endFunctionImpl() we do not have all the information about a parent subprogram or a referring subprogram (whether a subprogram inlined or not), so we can't guarantee we emit an imported entity correctly and place it in a proper subprogram tree. So now, we just gather needed details about the import itself and its parent entity (either a Subprogram or a LexicalBlock) during processing in DwarfDebug::endFunctionImpl(), but all the real work is done in DwarfDebug::endModule() when we have all the required information to make proper emission.

[jmmartinez]

I've added just a few minor remarks.

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

1117–1119

NIT: You could avoid writing the for loop

1692–1695

Nit: lookup returns the value in the map or returns a default value.

llvm/test/DebugInfo/Generic/split-dwarf-local-import3.ll

18–37

I'd be tempted to match the offset of the abstract subprogram and of the imported declaration too.
At least for me, it makes clear the intention of the test without running it.

What do you think ?

[krisb]

Apply review comments.

llvm/test/DebugInfo/Generic/split-dwarf-local-import3.ll

18–37

Good point, thank you!

[krisb]

Rebase.

[dzhidzhoev]

See https://reviews.llvm.org/D143984#4341780

[dzhidzhoev]

Rebased.

[dzhidzhoev]

This comment was removed by dzhidzhoev.

[dzhidzhoev]

Fixed split-dwarf-local-import*.ll tests.

[dzhidzhoev]

Added AutoUpdater, moving function-local imported entities belonging to DICompileUnit to a corresponding DISubprogram.

clang/test/CodeGenCXX/debug-info-namespace.cpp

 // CHECK: [[VAR_FWD:![0-9]+]] = distinct !DIGlobalVariable(name: "var_fwd",{{.*}} scope: [[NS]],
 // CHECK-SAME:                                             line: 44
 // CHECK-SAME:                                             isDefinition: true
 // CHECK: distinct !DIGlobalVariable(name: "var_i",{{.*}} scope: [[INLINE:![0-9]+]],
 // CHECK: [[INLINE]] = !DINamespace(name: "I", scope: [[CTXT]], exportSymbols: true)
 // CHECK: !DINamespace(scope: null)
 // CHECK: [[CU:![0-9]+]] = distinct !DICompileUnit(
 // CHECK-SAME:                            imports: [[MODULES:![0-9]*]]
-// CHECK: [[MODULES]] = !{[[M1:![0-9]+]], [[M2:![0-9]+]], [[M3:![0-9]+]], [[M4:![0-9]+]], [[M5:![0-9]+]], [[M6:![0-9]+]], [[M7:![0-9]+]], [[M8:![0-9]+]], [[M9:![0-9]+]], [[M10:![0-9]+]], [[M11:![0-9]+]], [[M12:![0-9]+]], [[M13:![0-9]+]], [[M14:![0-9]+]], [[M15:![0-9]+]], [[M16:![0-9]+]], [[M17:![0-9]+]]
+// CHECK: [[MODULES]] = !{[[M1:![0-9]+]], [[M2:![0-9]+]], [[M3:![0-9]+]], [[M4:![0-9]+]]}
 // CHECK: [[M1]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[CTXT]], entity: [[NS]], file: [[FOOCPP]], line: 15)
-
 // CHECK: [[M2]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[CU]], entity: [[CTXT]],
 // CHECK: [[M3]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "E", scope: [[CU]], entity: [[CTXT]], file: [[FOOCPP]], line: 19)
-// CHECK: [[M4]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[LEX2:![0-9]+]], entity: [[NS]], file: [[FOOCPP]], line: 23)
+// CHECK: [[M4]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[CTXT]], entity: [[I]]
+// CHECK: [[F1:![0-9]+]] = distinct !DISubprogram(name: "f1",{{.*}} line: 4
+// CHECK-SAME:                           DISPFlagDefinition
+// CHECK: [[FUNC:![0-9]+]] = distinct !DISubprogram(name: "func",{{.*}} DISPFlagDefinition
+// CHECK-SAME:                             retainedNodes: [[FUNC_NODES:![0-9]*]]
+// CHECK: [[FUNC_NODES]] = !{[[M5:![0-9]+]], [[M6:![0-9]+]], [[M7:![0-9]+]], [[M8:![0-9]+]], [[M9:![0-9]+]], [[M10:![0-9]+]], [[M11:![0-9]+]], [[M12:![0-9]+]], [[M13:![0-9]+]], [[M14:![0-9]+]], [[M15:![0-9]+]], [[M16:![0-9]+]], [[M17:![0-9]+]]}
+// CHECK: [[M5]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[LEX2:![0-9]+]], entity: [[NS]], file: [[FOOCPP]], line: 23)
 // CHECK: [[LEX2]] = distinct !DILexicalBlock(scope: [[LEX1:![0-9]+]], file: [[FOOCPP]],
 // CHECK: [[LEX1]] = distinct !DILexicalBlock(scope: [[FUNC:![0-9]+]], file: [[FOOCPP]],
-
-// CHECK: [[FUNC:![0-9]+]] = distinct !DISubprogram(name: "func",{{.*}} DISPFlagDefinition
-// CHECK: [[M5]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[FUNC]], entity: [[CTXT:![0-9]+]],
-// CHECK: [[M6]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FOO:![0-9]+]], file: [[FOOCPP]], line: 27)
+// CHECK: [[M6]] = !DIImportedEntity(tag: DW_TAG_imported_module, scope: [[FUNC]], entity: [[CTXT]],
+// CHECK: [[M7]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FOO:![0-9]+]], file: [[FOOCPP]], line: 27)
 // CHECK: [[FOO]] = !DICompositeType(tag: DW_TAG_structure_type, name: "foo",
 // CHECK-SAME:                               line: 5
 // CHECK-SAME:                               DIFlagFwdDecl
-// CHECK: [[M7]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[BAR:![0-9]+]]
+// CHECK: [[M8]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[BAR:![0-9]+]]
 // CHECK: [[BAR]] = !DICompositeType(tag: DW_TAG_structure_type, name: "bar",
 // CHECK-SAME:                               line: 6
 // CHECK-SAME:                               DIFlagFwdDecl
-
-// CHECK: [[M8]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[F1:![0-9]+]]
-// CHECK: [[F1:![0-9]+]] = distinct !DISubprogram(name: "f1",{{.*}} line: 4
-// CHECK-SAME:                           DISPFlagDefinition
-// CHECK: [[M9]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[I]]
-// CHECK: [[M10]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[BAZ:![0-9]+]]
+// CHECK: [[M9]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[F1]]
+// CHECK: [[M10]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[I]]
+// CHECK: [[M11]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[BAZ:![0-9]+]]
 // CHECK: [[BAZ]] = !DIDerivedType(tag: DW_TAG_typedef, name: "baz", scope: [[NS]], file: [[FOOCPP]],
 // CHECK-SAME:                     baseType: [[BAR]]
-// CHECK: [[M11]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "X", scope: [[FUNC]], entity: [[CTXT]]
-// CHECK: [[M12]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "Y", scope: [[FUNC]], entity: [[M11]]
-// CHECK: [[M13]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[VAR_DECL:![0-9]+]]
+// CHECK: [[M12]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "X", scope: [[FUNC]], entity: [[CTXT]]
+// CHECK: [[M13]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "Y", scope: [[FUNC]], entity: [[M12]]
+// CHECK: [[M14]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[VAR_DECL:![0-9]+]]
 // CHECK: [[VAR_DECL]] = !DIGlobalVariable(name: "var_decl", linkageName: "{{[^"]*var_decl[^"]*}}", scope: [[NS]],{{.*}} line: 8,
-// CHECK: [[M14]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FUNC_DECL:![0-9]+]]
+// CHECK: [[M15]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FUNC_DECL:![0-9]+]]
 // CHECK: [[FUNC_DECL]] = !DISubprogram(name: "func_decl",
 // CHECK-SAME:                          scope: [[NS]], file: [[FOOCPP]], line: 9
-// CHECK: [[M15]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[VAR_FWD:![0-9]+]]
-// CHECK: [[M16]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FUNC_FWD:![0-9]+]]
+// CHECK: [[M16]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[VAR_FWD:![0-9]+]]
+// CHECK: [[M17]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[FUNC]], entity: [[FUNC_FWD:![0-9]+]]
 // CHECK: [[FUNC_FWD]] = distinct !DISubprogram(name: "func_fwd",{{.*}} line: 53,{{.*}} DISPFlagDefinition
-// CHECK: [[M17]] = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: [[CTXT]], entity: [[I]]
 // CHECK: distinct !DISubprogram(name: "c",{{.*}}, scope: ![[C:[0-9]+]],{{.*}}, line: 60,{{.*}} DISPFlagDefinition
 // CHECK: ![[C]] = !DINamespace(name: "C",
 
 // CHECK-GMLT: [[CU:![0-9]+]] = distinct !DICompileUnit(
 // CHECK-GMLT-SAME:                            emissionKind: LineTablesOnly,
 // CHECK-GMLT-NOT:                             imports:
 
 // CHECK-GMLI: [[CU:![0-9]+]] = distinct !DICompileUnit(
 // CHECK-GMLI-SAME:                            emissionKind: DebugDirectivesOnly,
 // CHECK-GMLI-NOT:                             imports:
 
 // CHECK-NOLIMIT: !DICompositeType(tag: DW_TAG_structure_type, name: "bar",{{.*}} line: 6,
 // CHECK-NOLIMIT-NOT:              DIFlagFwdDecl
 // CHECK-NOLIMIT-SAME:             ){{$}}

llvm/include/llvm/IR/DIBuilder.h

class DIBuilder {
     Function *LabelFn;       ///< llvm.dbg.label
     Function *AssignFn;      ///< llvm.dbg.assign
 
     SmallVector<TrackingMDNodeRef, 4> AllEnumTypes;
     /// Track the RetainTypes, since they can be updated later on.
     SmallVector<TrackingMDNodeRef, 4> AllRetainTypes;
     SmallVector<DISubprogram *, 4> AllSubprograms;
     SmallVector<Metadata *, 4> AllGVs;
-    SmallVector<TrackingMDNodeRef, 4> AllImportedModules;
+    SmallVector<TrackingMDNodeRef, 4> ImportedModules;
     /// Map Macro parent (which can be DIMacroFile or nullptr) to a list of
     /// Metadata all of type DIMacroNode.
     /// DIMacroNode's with nullptr parent are DICompileUnit direct children.
     MapVector<MDNode *, SetVector<Metadata *>> AllMacrosPerParent;
 
     /// Track nodes that may be unresolved.
     SmallVector<TrackingMDNodeRef, 4> UnresolvedNodes;
     bool AllowUnresolvedNodes;
 
-    /// Each subprogram's preserved local variables and labels.
+    /// Each subprogram's preserved local variables, labels and imported
+    /// entities.
     ///
     /// Do not use a std::vector.  Some versions of libc++ apparently copy
     /// instead of move on grow operations, and TrackingMDRef is expensive to
     /// copy.
     DenseMap<DISubprogram *, SmallVector<TrackingMDNodeRef, 4>>
         SubprogramTrackedNodes;
 
     SmallVectorImpl<TrackingMDNodeRef> &
+    getImportTrackingVector(const DIScope *S) {
+      return isa_and_nonnull<DILocalScope>(S)
+                 ? getSubprogramNodesTrackingVector(S)
+                 : ImportedModules;
+    }
+    SmallVectorImpl<TrackingMDNodeRef> &
     getSubprogramNodesTrackingVector(const DIScope *S) {
       return SubprogramTrackedNodes[cast<DILocalScope>(S)->getSubprogram()];
     }
 
     /// Create a temporary.
     ///
     /// Create an \a temporary node and track it in \a UnresolvedNodes.
     void trackIfUnresolved(MDNode *N);

llvm/lib/Bitcode/Reader/MetadataLoader.cpp

 #include "ValueList.h"
 
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/BitmaskEnum.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/ilist_iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/BinaryFormat/Dwarf.h"

 
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <deque>
 #include <iterator>
 #include <limits>
+#include <map>
 #include <optional>
 #include <string>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 #include <vector>
 namespace llvm {
 class Argument;
#endif
   // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
   DenseMap<unsigned, unsigned> MDKindMap;
 
   bool StripTBAA = false;
   bool HasSeenOldLoopTags = false;
   bool NeedUpgradeToDIGlobalVariableExpression = false;
   bool NeedDeclareExpressionUpgrade = false;
 
+  /// Map DILocalScope to the enclosing DISubprogram, if any.
+  DenseMap<DILocalScope *, DISubprogram *> ParentSubprogram;
+
   /// True if metadata is being parsed for a module being ThinLTO imported.
   bool IsImporting = false;
 
   Error parseOneMetadata(SmallVectorImpl<uint64_t> &Record, unsigned Code,
                          PlaceholderQueue &Placeholders, StringRef Blob,
                          unsigned &NextMetadataNo);
   Error parseMetadataStrings(ArrayRef<uint64_t> Record, StringRef Blob,
                              function_ref<void(StringRef)> CallBack);
for (auto &GV : TheModule.globals()) {
           auto *DGVE = DIGlobalVariableExpression::getDistinct(
               Context, DGV, DIExpression::get(Context, {}));
           GV.addMetadata(LLVMContext::MD_dbg, *DGVE);
         } else
           GV.addMetadata(LLVMContext::MD_dbg, *MD);
     }
   }
 
+  DISubprogram *findEnclosingSubprogram(DILocalScope *S) {
+    if (!S)
+      return nullptr;
+    if (auto *SP = ParentSubprogram[S]) {
+      return SP;
+    }
+
+    DILocalScope *InitialScope = S;
+    DenseSet<DILocalScope *> Visited;
+    while (S && !isa<DISubprogram>(S)) {
+      S = dyn_cast_or_null<DILocalScope>(S->getScope());
+      if (Visited.contains(S))
+        break;
+      Visited.insert(S);
+    }
+    ParentSubprogram[InitialScope] = llvm::dyn_cast_or_null<DISubprogram>(S);
+
+    return ParentSubprogram[InitialScope];
+  }
+
+  /// Move local imports from DICompileUnit's 'imports' field to
+  /// DISubprogram's retainedNodes.
+  void upgradeCULocals() {
+    if (NamedMDNode *CUNodes = TheModule.getNamedMetadata("llvm.dbg.cu")) {
+      for (unsigned I = 0, E = CUNodes->getNumOperands(); I != E; ++I) {
+        auto *CU = dyn_cast<DICompileUnit>(CUNodes->getOperand(I));
+        if (!CU)
+          continue;
+
+        if (auto *RawImported = CU->getRawImportedEntities()) {
+          // Collect a set of imported entities to be moved.
+          SmallPtrSet<Metadata *, 8> EntitiesToRemove;
+          for (Metadata *Op : CU->getImportedEntities()->operands()) {
+            auto *IE = cast<DIImportedEntity>(Op);
+            if (auto *S = dyn_cast_or_null<DILocalScope>(IE->getScope())) {
+              EntitiesToRemove.insert(IE);
+            }
+          }
+
+          if (!EntitiesToRemove.empty()) {
+            // Make a new list of CU's 'imports'.
+            SmallVector<Metadata *> NewImports;
+            for (Metadata *Op : CU->getImportedEntities()->operands()) {
+              if (!EntitiesToRemove.contains(cast<DIImportedEntity>(Op))) {
+                NewImports.push_back(Op);
+              }
+            }
+
+            // Find DISubprogram corresponding to each entity.
+            std::map<DISubprogram *, SmallVector<Metadata *>> SPToEntities;
+            for (auto *I : EntitiesToRemove) {
+              auto *Entity = cast<DIImportedEntity>(I);
+              if (auto *SP = findEnclosingSubprogram(
+                      cast<DILocalScope>(Entity->getScope()))) {
+                SPToEntities[SP].push_back(Entity);
+              }
+            }
+
+            // Update DISubprograms' retainedNodes.
+            for (auto I = SPToEntities.begin(); I != SPToEntities.end(); ++I) {
+              auto *SP = I->first;
+              auto RetainedNodes = SP->getRetainedNodes();
+              SmallVector<Metadata *> MDs(RetainedNodes.begin(),
+                                          RetainedNodes.end());
+              MDs.append(I->second);
+              SP->replaceRetainedNodes(MDNode::get(Context, MDs));
+            }
+
+            // Remove entities with local scope from CU.
+            CU->replaceImportedEntities(MDTuple::get(Context, NewImports));
+          }
+        }
+      }
+    }
+
+    ParentSubprogram.clear();
+  }
+
   /// Remove a leading DW_OP_deref from DIExpressions in a dbg.declare that
   /// describes a function argument.
   void upgradeDeclareExpressions(Function &F) {
     if (!NeedDeclareExpressionUpgrade)
       return;
 
     for (auto &BB : F)
       for (auto &I : BB)
Error upgradeDIExpression(uint64_t FromVersion,
     }
 
     return Error::success();
   }
 
   void upgradeDebugInfo() {
     upgradeCUSubprograms();
     upgradeCUVariables();
+    upgradeCULocals();
   }
 
   void callMDTypeCallback(Metadata **Val, unsigned TypeID);
 
 public:
   MetadataLoaderImpl(BitstreamCursor &Stream, Module &TheModule,
                      BitcodeReaderValueList &ValueList,
                      MetadataLoaderCallbacks Callbacks, bool IsImporting)

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

class DwarfCompileUnit final : public DwarfUnit {
   DwarfCompileUnit *Skeleton = nullptr;
 
   /// The start of the unit within its section.
   MCSymbol *LabelBegin = nullptr;
 
   /// The start of the unit macro info within macro section.
   MCSymbol *MacroLabelBegin;
 
-  using ImportedEntityList = SmallVector<const MDNode *, 8>;
-  using ImportedEntityMap = DenseMap<const MDNode *, ImportedEntityList>;
-
-  ImportedEntityMap ImportedEntities;
-
   /// GlobalNames - A map of globally visible named entities for this unit.
   StringMap<const DIE *> GlobalNames;
 
   /// GlobalTypes - A map of globally visible types for this unit.
   StringMap<const DIE *> GlobalTypes;
 
   // List of ranges for a given compile unit.
   SmallVector<RangeSpan, 2> CURanges;
 
   // The base address of this unit, if any. Used for relative references in
   // ranges/locs.
   const MCSymbol *BaseAddress = nullptr;
 
-  DenseMap<const MDNode *, DIE *> AbstractSPDies;
+  using MDNodeSetVector =
+      SetVector<const MDNode *, SmallVector<const MDNode *, 4>,
+                SmallPtrSet<const MDNode *, 4>>;
+
+  // List of entities (either static locals, types or imports) that
+  // belong to subprograms within this CU.
+  MDNodeSetVector DeferredLocalDecls;
+
+  // List of concrete lexical block scopes belong to subprograms within this CU.
+  DenseMap<const DILocalScope *, DIE *> LexicalBlockDIEs;
+
+  // List of abstract local scopes (either DISubprogram or DILexicalBlock).
+  DenseMap<const DILocalScope *, DIE *> AbstractLocalScopeDIEs;
+
   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
 
   /// DWO ID for correlating skeleton and split units.
   uint64_t DWOId = 0;
 
   const DIFile *LastFile = nullptr;
   unsigned LastFileID;
 
   /// Construct a DIE for the given DbgVariable without initializing the
   /// DbgVariable's DIE reference.
   DIE *constructVariableDIEImpl(const DbgVariable &DV, bool Abstract);
 
   bool isDwoUnit() const override;
 
-  DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
+  DenseMap<const DILocalScope *, DIE *> &getAbstractScopeDIEs() {
     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
-      return AbstractSPDies;
-    return DU->getAbstractSPDies();
+      return AbstractLocalScopeDIEs;
+    return DU->getAbstractScopeDIEs();
   }
 
   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
       return AbstractEntities;
     return DU->getAbstractEntities();
   }
 
public:
   /// DW_FORM_addr only.
   void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
                             const MCSymbol *Label);
 
   DwarfCompileUnit &getCU() override { return *this; }
 
   unsigned getOrCreateSourceID(const DIFile *File) override;
 
-  void addImportedEntity(const DIImportedEntity* IE) {
-    DIScope *Scope = IE->getScope();
-    assert(Scope && "Invalid Scope encoding!");
-    if (!isa<DILocalScope>(Scope))
-      // No need to add imported enities that are not local declaration.
-      return;
-
-    auto *LocalScope = cast<DILocalScope>(Scope)->getNonLexicalBlockFileScope();
-    ImportedEntities[LocalScope].push_back(IE);
-  }
-
   /// addRange - Add an address range to the list of ranges for this unit.
   void addRange(RangeSpan Range);
 
   void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
 
   /// Find DIE for the given subprogram and attach appropriate
   /// DW_AT_low_pc and DW_AT_high_pc attributes. If there are global
   /// variables in this scope then create and insert DIEs for these
public:
   /// This scope represents an inlined body of a function. Construct a
   /// DIE to represent this concrete inlined copy of the function.
   DIE *constructInlinedScopeDIE(LexicalScope *Scope, DIE &ParentScopeDIE);
 
   /// Construct new DW_TAG_lexical_block for this scope and
   /// attach DW_AT_low_pc/DW_AT_high_pc labels.
   DIE *constructLexicalScopeDIE(LexicalScope *Scope);
 
+  /// Get a DIE for the given DILexicalBlock.
+  /// Note that this function assumes that the DIE has been already created
+  /// and it's an error, if it hasn't.
+  DIE *getLexicalBlockDIE(const DILexicalBlock *LB);
+
   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
   DIE *constructVariableDIE(DbgVariable &DV, bool Abstract = false);
 
   DIE *constructVariableDIE(DbgVariable &DV, const LexicalScope &Scope,
                             DIE *&ObjectPointer);
 
   /// Construct a DIE for the given DbgLabel.
   DIE *constructLabelDIE(DbgLabel &DL, const LexicalScope &Scope);
 
   void createBaseTypeDIEs();
 
+  /// Construct a DIE for a given scope.
+  /// This instance of 'getOrCreateContextDIE()' can handle DILocalScope.
+  DIE *getOrCreateContextDIE(const DIScope *Ty) override;
+
   /// Construct a DIE for this subprogram scope.
   DIE &constructSubprogramScopeDIE(const DISubprogram *Sub,
                                    LexicalScope *Scope);
 
   DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
 
   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 
DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
                                  const MCSymbol *CallAddr, unsigned CallReg);
   /// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
   /// were collected by the \ref collectCallSiteParameters.
   /// Note: The order of parameters does not matter, since debuggers recognize
   ///       call site parameters by the DW_AT_location attribute.
   void constructCallSiteParmEntryDIEs(DIE &CallSiteDIE,
                                       SmallVector<DbgCallSiteParam, 4> &Params);
 
-  /// Construct import_module DIE.
-  DIE *constructImportedEntityDIE(const DIImportedEntity *Module);
+  /// Get or create a DIE for an imported entity.
+  DIE *getOrCreateImportedEntityDIE(const DIImportedEntity *IE);
+  DIE *constructImportedEntityDIE(const DIImportedEntity *IE);
 
   void finishSubprogramDefinition(const DISubprogram *SP);
   void finishEntityDefinition(const DbgEntity *Entity);
 
   /// Find abstract variable associated with Var.
   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
   DbgEntity *getExistingAbstractEntity(const DINode *Node);
   void createAbstractEntity(const DINode *Node, LexicalScope *Scope);
public:
   const MCSymbol *getBaseAddress() const { return BaseAddress; }
 
   uint64_t getDWOId() const { return DWOId; }
   void setDWOId(uint64_t DwoId) { DWOId = DwoId; }
 
   bool hasDwarfPubSections() const;
 
   void addBaseTypeRef(DIEValueList &Die, int64_t Idx);
+
+  MDNodeSetVector &getDeferredLocalDecls() { return DeferredLocalDecls; }
 };
 
 } // end namespace llvm
 
 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFCOMPILEUNIT_H

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

 
 DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope,
                                                 DIE &ParentScopeDIE) {
   assert(Scope->getScopeNode());
   auto *DS = Scope->getScopeNode();
   auto *InlinedSP = getDISubprogram(DS);
   // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
   // was inlined from another compile unit.
-  DIE *OriginDIE = getAbstractSPDies()[InlinedSP];
+  DIE *OriginDIE = getAbstractScopeDIEs()[InlinedSP];
   assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
 
   auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
   ParentScopeDIE.addChild(ScopeDIE);
   addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
 
   attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
 
DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope,
   return ScopeDIE;
 }
 
 // Construct new DW_TAG_lexical_block for this scope and attach
 // DW_AT_low_pc/DW_AT_high_pc labels.
 DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
   if (DD->isLexicalScopeDIENull(Scope))
     return nullptr;
+  const auto *DS = Scope->getScopeNode();
 
   auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
-  if (Scope->isAbstractScope())
+  if (Scope->isAbstractScope()) {
+    assert(!getAbstractScopeDIEs().count(DS) &&
+           "Abstract DIE for this scope exists!");
+    getAbstractScopeDIEs()[DS] = ScopeDIE;
     return ScopeDIE;
+  }
+  if (!Scope->getInlinedAt()) {
+    assert(!LexicalBlockDIEs.count(DS) &&
+           "Concrete out-of-line DIE for this scope exists!");
+    LexicalBlockDIEs[DS] = ScopeDIE;
+  }
 
   attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
 
   return ScopeDIE;
 }
 
 /// constructVariableDIE - Construct a DIE for the given DbgVariable.
 DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
   for (auto &DV : Vars.Args)
     ScopeDIE.addChild(constructVariableDIE(*DV.second, *Scope, ObjectPointer));
 
   // Emit local variables.
   auto Locals = sortLocalVars(Vars.Locals);
   for (DbgVariable *DV : Locals)
     ScopeDIE.addChild(constructVariableDIE(*DV, *Scope, ObjectPointer));
 
-  // Emit imported entities (skipped in gmlt-like data).
-  if (!includeMinimalInlineScopes()) {
-    for (const auto *IE : ImportedEntities[Scope->getScopeNode()])
-      ScopeDIE.addChild(constructImportedEntityDIE(cast<DIImportedEntity>(IE)));
-  }
-
   // Emit labels.
   for (DbgLabel *DL : DU->getScopeLabels().lookup(Scope))
     ScopeDIE.addChild(constructLabelDIE(*DL, *Scope));
 
+  // Track other local entities (skipped in gmlt-like data).
+  // This creates mapping between CU and a set of local declarations that
+  // should be emitted for subprograms in this CU.
+  if (!includeMinimalInlineScopes() && !Scope->getInlinedAt()) {
+    auto &LocalDecls = DD->getLocalDeclsForScope(Scope->getScopeNode());
+    DeferredLocalDecls.insert(LocalDecls.begin(), LocalDecls.end());
+  }
+
   // Emit inner lexical scopes.
-  auto needToEmitLexicalScope = [this](LexicalScope *LS) {
-    if (isa<DISubprogram>(LS->getScopeNode()))
-      return true;
-    auto Vars = DU->getScopeVariables().lookup(LS);
+  auto skipLexicalScope = [this](LexicalScope *S) -> bool {
+    if (isa<DISubprogram>(S->getScopeNode()))
+      return false;
+    auto Vars = DU->getScopeVariables().lookup(S);
     if (!Vars.Args.empty() || !Vars.Locals.empty())
-      return true;
-    if (!includeMinimalInlineScopes() &&
-        !ImportedEntities[LS->getScopeNode()].empty())
-      return true;
       return false;
+    return includeMinimalInlineScopes() ||
+           DD->getLocalDeclsForScope(S->getScopeNode()).empty();
   };
   for (LexicalScope *LS : Scope->getChildren()) {
     // If the lexical block doesn't have non-scope children, skip
     // its emission and put its children directly to the parent scope.
-    if (needToEmitLexicalScope(LS))
-      constructScopeDIE(LS, ScopeDIE);
-    else
+    if (skipLexicalScope(LS))
       createAndAddScopeChildren(LS, ScopeDIE);
+    else
+      constructScopeDIE(LS, ScopeDIE);
   }
 
   return ObjectPointer;
 }
 
 void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
     LexicalScope *Scope) {
-  DIE *&AbsDef = getAbstractSPDies()[Scope->getScopeNode()];
-  if (AbsDef)
-    return;
-
   auto *SP = cast<DISubprogram>(Scope->getScopeNode());
+  if (getAbstractScopeDIEs().count(SP))
+    return;
 
   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());
   }
 
   // Passing null as the associated node because the abstract definition
   // shouldn't be found by lookup.
-  AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
-  ContextCU->applySubprogramAttributesToDefinition(SP, *AbsDef);
-  ContextCU->addSInt(*AbsDef, dwarf::DW_AT_inline,
+  DIE &AbsDef = ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram,
+                                           *ContextDIE, nullptr);
+
+  // Store the DIE before creating children.
+  ContextCU->getAbstractScopeDIEs()[SP] = &AbsDef;
+
+  ContextCU->applySubprogramAttributesToDefinition(SP, AbsDef);
+  ContextCU->addSInt(AbsDef, dwarf::DW_AT_inline,
                      DD->getDwarfVersion() <= 4 ? std::optional<dwarf::Form>()
                                                 : dwarf::DW_FORM_implicit_const,
                      dwarf::DW_INL_inlined);
-  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 {
   return DD->getDwarfVersion() == 4 && !DD->tuneForLLDB();
 }
 
 dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUTag(dwarf::Tag Tag) const {
   if (!useGNUAnalogForDwarf5Feature())
DIE *DwarfCompileUnit::constructImportedEntityDIE(
   DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
   insertDIE(Module, IMDie);
   DIE *EntityDie;
   auto *Entity = Module->getEntity();
   if (auto *NS = dyn_cast<DINamespace>(Entity))
     EntityDie = getOrCreateNameSpace(NS);
   else if (auto *M = dyn_cast<DIModule>(Entity))
     EntityDie = getOrCreateModule(M);
-  else if (auto *SP = dyn_cast<DISubprogram>(Entity))
+  else if (auto *SP = dyn_cast<DISubprogram>(Entity)) {
+    // If there is an abstract subprogram, refer to it. Note that this assumes
+    // that all the abstract subprograms have been already created (which is
+    // correct until imported entities get emitted in DwarfDebug::endModule()).
+    if (auto *AbsSPDie = getAbstractScopeDIEs().lookup(SP))
+      EntityDie = AbsSPDie;
+    else
       EntityDie = getOrCreateSubprogramDIE(SP);
-  else if (auto *T = dyn_cast<DIType>(Entity))
+  } else if (auto *T = dyn_cast<DIType>(Entity))
     EntityDie = getOrCreateTypeDIE(T);
   else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
     EntityDie = getOrCreateGlobalVariableDIE(GV, {});
+  else if (auto *IE = dyn_cast<DIImportedEntity>(Entity))
+    EntityDie = getOrCreateImportedEntityDIE(IE);
   else
     EntityDie = getDIE(Entity);
   assert(EntityDie);
   addSourceLine(*IMDie, Module->getLine(), Module->getFile());
   addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
   StringRef Name = Module->getName();
   if (!Name.empty()) {
     addString(*IMDie, dwarf::DW_AT_name, Name);
if (!Element)
       continue;
     IMDie->addChild(
         constructImportedEntityDIE(cast<DIImportedEntity>(Element)));
   }
 
   return IMDie;
 }
 
+DIE *DwarfCompileUnit::getOrCreateImportedEntityDIE(
+    const DIImportedEntity *IE) {
+
+  // Check for pre-existence.
+  if (DIE *Die = getDIE(IE))
+    return Die;
+
+  DIE *ContextDIE = getOrCreateContextDIE(IE->getScope());
+  assert(ContextDIE && "Empty scope for the imported entity!");
+
+  DIE *IMDie = constructImportedEntityDIE(IE);
+  ContextDIE->addChild(IMDie);
+  return IMDie;
+}
+
 void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
   DIE *D = getDIE(SP);
-  if (DIE *AbsSPDIE = getAbstractSPDies().lookup(SP)) {
+  if (DIE *AbsSPDIE = getAbstractScopeDIEs().lookup(SP)) {
     if (D)
       // If this subprogram has an abstract definition, reference that
       addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
   } else {
     assert(D || includeMinimalInlineScopes());
     if (D)
       // And attach the attributes
       applySubprogramAttributesToDefinition(SP, *D);
for (auto &Btr : reverse(ExprRefedBaseTypes)) {
     addUInt(Die, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1, Btr.Encoding);
     // Round up to smallest number of bytes that contains this number of bits.
     addUInt(Die, dwarf::DW_AT_byte_size, std::nullopt,
             divideCeil(Btr.BitSize, 8));
 
     Btr.Die = &Die;
   }
 }
+
+DIE *DwarfCompileUnit::getLexicalBlockDIE(const DILexicalBlock *LB) {
+  // Assume if there is an abstract tree all the DIEs are already emitted.
+  bool isAbstract = getAbstractScopeDIEs().count(LB->getSubprogram());
+  if (isAbstract && getAbstractScopeDIEs().count(LB))
+    return getAbstractScopeDIEs()[LB];
+  assert(!isAbstract && "Missed lexical block DIE in abstract tree!");
+
+  // Return a concrete DIE if it exists or nullptr otherwise.
+  return LexicalBlockDIEs.lookup(LB);
+}
+
+DIE *DwarfCompileUnit::getOrCreateContextDIE(const DIScope *Context) {
+  if (isa_and_nonnull<DILocalScope>(Context)) {
+    if (auto *LFScope = dyn_cast<DILexicalBlockFile>(Context))
+      Context = LFScope->getNonLexicalBlockFileScope();
+    if (auto *LScope = dyn_cast<DILexicalBlock>(Context))
+      return getLexicalBlockDIE(LScope);
+
+    // Otherwise the context must be a DISubprogram.
+    auto *SPScope = cast<DISubprogram>(Context);
+    if (getAbstractScopeDIEs().count(SPScope))
+      return getAbstractScopeDIEs()[SPScope];
+  }
+  return DwarfUnit::getOrCreateContextDIE(Context);
+}

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

class DwarfDebug : public DebugHandlerBase {
   /// Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
   /// can refer to them in spite of insertions into this list.
   DebugLocStream DebugLocs;
 
   /// This is a collection of subprogram MDNodes that are processed to
   /// create DIEs.
   SmallSetVector<const DISubprogram *, 16> ProcessedSPNodes;
 
+  /// Map function-local imported entities to their parent local scope
+  /// (either DILexicalBlock or DISubprogram) for a processed function
+  /// (including inlined subprograms).
+  using MDNodeSet = SetVector<const MDNode *, SmallVector<const MDNode *, 2>,
+                              SmallPtrSet<const MDNode *, 2>>;
+  DenseMap<const DILocalScope *, MDNodeSet> LocalDeclsPerLS;
+
   /// If nonnull, stores the current machine function we're processing.
   const MachineFunction *CurFn = nullptr;
 
   /// If nonnull, stores the CU in which the previous subprogram was contained.
   const DwarfCompileUnit *PrevCU = nullptr;
 
   /// As an optimization, there is no need to emit an entry in the directory
   /// table for the same directory as DW_AT_comp_dir.
private:
   MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
 
   const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
     return InfoHolder.getUnits();
   }
 
   using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
 
-  void ensureAbstractEntityIsCreated(DwarfCompileUnit &CU,
-                                     const DINode *Node,
-                                     const MDNode *Scope);
   void ensureAbstractEntityIsCreatedIfScoped(DwarfCompileUnit &CU,
                                              const DINode *Node,
                                              const MDNode *Scope);
 
   DbgEntity *createConcreteEntity(DwarfCompileUnit &TheCU,
                                   LexicalScope &Scope,
                                   const DINode *Node,
                                   const DILocation *Location,
private:
   void addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const;
 
   /// Create new DwarfCompileUnit for the given metadata node with tag
   /// DW_TAG_compile_unit.
   DwarfCompileUnit &getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit);
   void finishUnitAttributes(const DICompileUnit *DIUnit,
                             DwarfCompileUnit &NewCU);
 
-  /// Construct imported_module or imported_declaration DIE.
-  void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
-                                        const DIImportedEntity *N);
-
   /// Register a source line with debug info. Returns the unique
   /// label that was emitted and which provides correspondence to the
   /// source line list.
   void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
                         unsigned Flags);
 
   /// Populate LexicalScope entries with variables' info.
   void collectEntityInfo(DwarfCompileUnit &TheCU, const DISubprogram *SP,
public:
 
   static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT,
                                 const DbgValueLoc &Value,
                                 DwarfExpression &DwarfExpr);
 
   /// If the \p File has an MD5 checksum, return it as an MD5Result
   /// allocated in the MCContext.
   std::optional<MD5::MD5Result> getMD5AsBytes(const DIFile *File) const;
+
+  MDNodeSet &getLocalDeclsForScope(const DILocalScope *S) {
+    return LocalDeclsPerLS[S];
+  }
 };
 
 } // end namespace llvm
 
 #endif // LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

void DwarfDebug::addSubprogramNames(const DICompileUnit &CU,
 
   if (SP->getName() != "")
     addAccelName(CU, SP->getName(), Die);
 
   // If the linkage name is different than the name, go ahead and output that as
   // well into the name table. Only do that if we are going to actually emit
   // that name.
   if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName() &&
-      (useAllLinkageNames() || InfoHolder.getAbstractSPDies().lookup(SP)))
+      (useAllLinkageNames() || InfoHolder.getAbstractScopeDIEs().lookup(SP)))
     addAccelName(CU, SP->getLinkageName(), Die);
 
   // If this is an Objective-C selector name add it to the ObjC accelerator
   // too.
   if (isObjCClass(SP->getName())) {
     StringRef Class, Category;
     getObjCClassCategory(SP->getName(), Class, Category);
     addAccelObjC(CU, Class, Die);
DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
   }
   CompilationDir = DIUnit->getDirectory();
 
   auto OwnedUnit = std::make_unique<DwarfCompileUnit>(
       InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
   DwarfCompileUnit &NewCU = *OwnedUnit;
   InfoHolder.addUnit(std::move(OwnedUnit));
 
-  for (auto *IE : DIUnit->getImportedEntities())
-    NewCU.addImportedEntity(IE);
-
   // LTO with assembly output shares a single line table amongst multiple CUs.
   // To avoid the compilation directory being ambiguous, let the line table
   // explicitly describe the directory of all files, never relying on the
   // compilation directory.
   if (!Asm->OutStreamer->hasRawTextSupport() || SingleCU)
     Asm->OutStreamer->emitDwarfFile0Directive(
         CompilationDir, DIUnit->getFilename(), getMD5AsBytes(DIUnit->getFile()),
         DIUnit->getSource(), NewCU.getUniqueID());
 
   if (useSplitDwarf()) {
     NewCU.setSkeleton(constructSkeletonCU(NewCU));
     NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
   } else {
     finishUnitAttributes(DIUnit, NewCU);
     NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoSection());
   }
 
   CUMap.insert({DIUnit, &NewCU});
   CUDieMap.insert({&NewCU.getUnitDie(), &NewCU});
   return NewCU;
 }
 
-void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
-                                                  const DIImportedEntity *N) {
-  if (isa<DILocalScope>(N->getScope()))
-    return;
-  if (DIE *D = TheCU.getOrCreateContextDIE(N->getScope()))
-    D->addChild(TheCU.constructImportedEntityDIE(N));
-}
-
 /// Sort and unique GVEs by comparing their fragment offset.
 static SmallVectorImpl<DwarfCompileUnit::GlobalExpr> &
 sortGlobalExprs(SmallVectorImpl<DwarfCompileUnit::GlobalExpr> &GVEs) {
   llvm::sort(
       GVEs, [](DwarfCompileUnit::GlobalExpr A, DwarfCompileUnit::GlobalExpr B) {
         // Sort order: first null exprs, then exprs without fragment
         // info, then sort by fragment offset in bits.
         // FIXME: Come up with a more comprehensive comparator so
void DwarfDebug::beginModule(Module *M) {
   }
 
   // Create the symbol that points to the first entry following the debug
   // address table (.debug_addr) header.
   AddrPool.setLabel(Asm->createTempSymbol("addr_table_base"));
   DebugLocs.setSym(Asm->createTempSymbol("loclists_table_base"));
 
   for (DICompileUnit *CUNode : M->debug_compile_units()) {
-    // FIXME: Move local imported entities into a list attached to the
-    // subprogram, then this search won't be needed and a
-    // getImportedEntities().empty() test should go below with the rest.
-    bool HasNonLocalImportedEntities = llvm::any_of(
-        CUNode->getImportedEntities(), [](const DIImportedEntity *IE) {
-          return !isa<DILocalScope>(IE->getScope());
-        });
-
-    if (!HasNonLocalImportedEntities && CUNode->getEnumTypes().empty() &&
-        CUNode->getRetainedTypes().empty() &&
+    if (CUNode->getImportedEntities().empty() &&
+        CUNode->getEnumTypes().empty() && CUNode->getRetainedTypes().empty() &&
         CUNode->getGlobalVariables().empty() && CUNode->getMacros().empty())
       continue;
 
     DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(CUNode);
 
     // Global Variables.
     for (auto *GVE : CUNode->getGlobalVariables()) {
       // Don't bother adding DIGlobalVariableExpressions listed in the CU if we
void DwarfDebug::endModule() {
   assert(CurFn == nullptr);
   assert(CurMI == nullptr);
 
   for (const auto &P : CUMap) {
     const auto *CUNode = cast<DICompileUnit>(P.first);
     DwarfCompileUnit *CU = &*P.second;
 
     // Emit imported entities.
-    for (auto *IE : CUNode->getImportedEntities())
-      constructAndAddImportedEntityDIE(*CU, IE);
+    for (auto *IE : CUNode->getImportedEntities()) {
+      assert(!isa_and_nonnull<DILocalScope>(IE->getScope()) &&
+             "Unexpected function-local entity in 'imports' CU field.");
+      CU->getOrCreateImportedEntityDIE(IE);
+    }
+    for (const auto *D : CU->getDeferredLocalDecls()) {
+      if (auto *IE = dyn_cast<DIImportedEntity>(D))
+        CU->getOrCreateImportedEntityDIE(IE);
+      else
+        llvm_unreachable("Unexpected local retained node!");
+    }
 
     // Emit base types.
     CU->createBaseTypeDIEs();
   }
 
   // If we aren't actually generating debug info (check beginModule -
   // conditionalized on the presence of the llvm.dbg.cu metadata node)
   if (!Asm || !MMI->hasDebugInfo())
void DwarfDebug::endModule() {
 
   // Emit the pubnames and pubtypes sections if requested.
   emitDebugPubSections();
 
   // clean up.
   // FIXME: AbstractVariables.clear();
 }
 
-void DwarfDebug::ensureAbstractEntityIsCreated(DwarfCompileUnit &CU,
-                                               const DINode *Node,
-                                               const MDNode *ScopeNode) {
-  if (CU.getExistingAbstractEntity(Node))
-    return;
-
-  CU.createAbstractEntity(Node, LScopes.getOrCreateAbstractScope(
-                                       cast<DILocalScope>(ScopeNode)));
-}
-
 void DwarfDebug::ensureAbstractEntityIsCreatedIfScoped(DwarfCompileUnit &CU,
     const DINode *Node, const MDNode *ScopeNode) {
   if (CU.getExistingAbstractEntity(Node))
     return;
 
   if (LexicalScope *Scope =
           LScopes.findAbstractScope(cast_or_null<DILocalScope>(ScopeNode)))
     CU.createAbstractEntity(Node, Scope);
 }
 
+static const DILocalScope *getRetainedNodeScope(const MDNode *N) {
+  const DIScope *S;
+  if (const auto *LV = dyn_cast<DILocalVariable>(N))
+    S = LV->getScope();
+  else if (const auto *L = dyn_cast<DILabel>(N))
+    S = L->getScope();
+  else if (const auto *IE = dyn_cast<DIImportedEntity>(N))
+    S = IE->getScope();
+  else
+    llvm_unreachable("Unexpected retained node!");
+
+  // Ensure the scope is not a DILexicalBlockFile.
+  return cast<DILocalScope>(S)->getNonLexicalBlockFileScope();
+}
+
 // Collect variable information from side table maintained by MF.
 void DwarfDebug::collectVariableInfoFromMFTable(
     DwarfCompileUnit &TheCU, DenseSet<InlinedEntity> &Processed) {
   SmallDenseMap<InlinedEntity, DbgVariable *> MFVars;
   LLVM_DEBUG(dbgs() << "DwarfDebug: collecting variables from MF side table\n");
   for (const auto &VI : Asm->MF->getVariableDbgInfo()) {
     if (!VI.Var)
       continue;
for (const auto &I : DbgLabels) {
     Processed.insert(IL);
     /// At this point, the temporary label is created.
     /// Save the temporary label to DbgLabel entity to get the
     /// actually address when generating Dwarf DIE.
     MCSymbol *Sym = getLabelBeforeInsn(MI);
     createConcreteEntity(TheCU, *Scope, Label, IL.second, Sym);
   }
 
-  // Collect info for variables/labels that were optimized out.
+  // Collect info for retained nodes.
   for (const DINode *DN : SP->getRetainedNodes()) {
+    const auto *LS = getRetainedNodeScope(DN);
+    if (isa<DILocalVariable>(DN) || isa<DILabel>(DN)) {
       if (!Processed.insert(InlinedEntity(DN, nullptr)).second)
         continue;
-    LexicalScope *Scope = nullptr;
-    if (auto *DV = dyn_cast<DILocalVariable>(DN)) {
-      Scope = LScopes.findLexicalScope(DV->getScope());
-    } else if (auto *DL = dyn_cast<DILabel>(DN)) {
-      Scope = LScopes.findLexicalScope(DL->getScope());
+      LexicalScope *LexS = LScopes.findLexicalScope(LS);
+      if (LexS)
+        createConcreteEntity(TheCU, *LexS, DN, nullptr);
+    } else {
+      LocalDeclsPerLS[LS].insert(DN);
     }
-
-    if (Scope)
-      createConcreteEntity(TheCU, *Scope, DN, nullptr);
   }
 }
 
 // Process beginning of an instruction.
 void DwarfDebug::beginInstruction(const MachineInstr *MI) {
   const MachineFunction &MF = *MI->getMF();
   const auto *SP = MF.getFunction().getSubprogram();
   bool NoDebug =
if (!TheCU.getCUNode()->getDebugInfoForProfiling() &&
 
     assert(InfoHolder.getScopeVariables().empty());
     PrevLabel = nullptr;
     CurFn = nullptr;
     return;
   }
 
 #ifndef NDEBUG
-  size_t NumAbstractScopes = LScopes.getAbstractScopesList().size();
+  size_t NumAbstractSubprograms = LScopes.getAbstractScopesList().size();
 #endif
-  // Construct abstract scopes.
   for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
     const auto *SP = cast<DISubprogram>(AScope->getScopeNode());
     for (const DINode *DN : SP->getRetainedNodes()) {
-      if (!Processed.insert(InlinedEntity(DN, nullptr)).second)
-        continue;
-
-      const MDNode *Scope = nullptr;
-      if (auto *DV = dyn_cast<DILocalVariable>(DN))
-        Scope = DV->getScope();
-      else if (auto *DL = dyn_cast<DILabel>(DN))
-        Scope = DL->getScope();
-      else
-        llvm_unreachable("Unexpected DI type!");
-
+      const auto *LS = getRetainedNodeScope(DN);
+      // Ensure LexicalScope is created for the scope of this node.
+      auto *LexS = LScopes.getOrCreateAbstractScope(LS);
+      assert(LexS && "Expected the LexicalScope to be created.");
+      if (isa<DILocalVariable>(DN) || isa<DILabel>(DN)) {
         // Collect info for variables/labels that were optimized out.
-      ensureAbstractEntityIsCreated(TheCU, DN, Scope);
-      assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes
-             && "ensureAbstractEntityIsCreated inserted abstract scopes");
+        if (!Processed.insert(InlinedEntity(DN, nullptr)).second ||
+            TheCU.getExistingAbstractEntity(DN))
+          continue;
+        TheCU.createAbstractEntity(DN, LexS);
+      } else {
+        // Remember the node if this is a local declarations.
+        LocalDeclsPerLS[LS].insert(DN);
+      }
+      assert(
+          LScopes.getAbstractScopesList().size() == NumAbstractSubprograms &&
+          "getOrCreateAbstractScope() inserted an abstract subprogram scope");
     }
     constructAbstractSubprogramScopeDIE(TheCU, AScope);
   }
 
   ProcessedSPNodes.insert(SP);
   DIE &ScopeDIE = TheCU.constructSubprogramScopeDIE(SP, FnScope);
   if (auto *SkelCU = TheCU.getSkeleton())
     if (!LScopes.getAbstractScopesList().empty() &&
         TheCU.getCUNode()->getSplitDebugInlining())
       SkelCU->constructSubprogramScopeDIE(SP, FnScope);
 
   // Construct call site entries.
   constructCallSiteEntryDIEs(*SP, TheCU, ScopeDIE, *MF);
 
   // Clear debug info
   // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
   // DbgVariables except those that are also in AbstractVariables (since they
   // can be used cross-function)
   InfoHolder.getScopeVariables().clear();
   InfoHolder.getScopeLabels().clear();
+  LocalDeclsPerLS.clear();
   PrevLabel = nullptr;
   CurFn = nullptr;
 }
 
 // Register a source line with debug info. Returns the  unique label that was
 // emitted and which provides correspondence to the source line list.
 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
                                   unsigned Flags) {

llvm/lib/CodeGen/AsmPrinter/DwarfFile.h

 
 namespace llvm {
 
 class AsmPrinter;
 class DbgEntity;
 class DbgVariable;
 class DbgLabel;
 class DINode;
+class DILocalScope;
 class DwarfCompileUnit;
 class DwarfUnit;
 class LexicalScope;
 class MCSection;
 class MDNode;
 
 // Data structure to hold a range for range lists.
 struct RangeSpan {
class DwarfFile {
   /// Collection of DbgVariables of each lexical scope.
   DenseMap<LexicalScope *, ScopeVars> ScopeVariables;
 
   /// Collection of DbgLabels of each lexical scope.
   using LabelList = SmallVector<DbgLabel *, 4>;
   DenseMap<LexicalScope *, LabelList> ScopeLabels;
 
   // Collection of abstract subprogram DIEs.
-  DenseMap<const MDNode *, DIE *> AbstractSPDies;
+  DenseMap<const DILocalScope *, DIE *> AbstractLocalScopeDIEs;
   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
 
   /// 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
   /// of in DwarfCompileUnit.
   DenseMap<const MDNode *, DIE *> DITypeNodeToDieMap;
 
 public:
public:
   DenseMap<LexicalScope *, ScopeVars> &getScopeVariables() {
     return ScopeVariables;
   }
 
   DenseMap<LexicalScope *, LabelList> &getScopeLabels() {
     return ScopeLabels;
   }
 
-  DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
-    return AbstractSPDies;
+  DenseMap<const DILocalScope *, DIE *> &getAbstractScopeDIEs() {
+    return AbstractLocalScopeDIEs;
   }
 
   DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
     return AbstractEntities;
   }
 
   void insertDIE(const MDNode *TypeMD, DIE *Die) {
     DITypeNodeToDieMap.insert(std::make_pair(TypeMD, Die));

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h

public:
 
   void applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
                                  bool SkipSPAttributes = false);
 
   /// Creates type DIE with specific context.
   DIE *createTypeDIE(const DIScope *Context, DIE &ContextDIE, const DIType *Ty);
 
   /// Find existing DIE or create new DIE for the given type.
-  DIE *getOrCreateTypeDIE(const MDNode *TyNode);
+  virtual DIE *getOrCreateTypeDIE(const MDNode *TyNode);
 
   /// Get context owner's DIE.
-  DIE *getOrCreateContextDIE(const DIScope *Context);
+  virtual DIE *getOrCreateContextDIE(const DIScope *Context);
 
   /// Construct DIEs for types that contain vtables.
   void constructContainingTypeDIEs();
 
   /// Construct function argument DIEs.
   void constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args);
 
   /// Create a DIE with the given Tag, add the DIE to its parent, and

llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp

bool DwarfUnit::applySubprogramDefinitionAttributes(const DISubprogram *SP,
 
   // Add the linkage name if we have one and it isn't in the Decl.
   StringRef LinkageName = SP->getLinkageName();
   assert(((LinkageName.empty() || DeclLinkageName.empty()) ||
           LinkageName == DeclLinkageName) &&
          "decl has a linkage name and it is different");
   if (DeclLinkageName.empty() &&
       // Always emit it for abstract subprograms.
-      (DD->useAllLinkageNames() || DU->getAbstractSPDies().lookup(SP)))
+      (DD->useAllLinkageNames() || DU->getAbstractScopeDIEs().lookup(SP)))
     addLinkageName(SPDie, LinkageName);
 
   if (!DeclDie)
     return false;
 
   // Refer to the function declaration where all the other attributes will be
   // found.
   addDIEEntry(SPDie, dwarf::DW_AT_specification, *DeclDie);

llvm/lib/IR/DIBuilder.cpp

DIBuilder::DIBuilder(Module &m, bool AllowUnresolvedNodes, DICompileUnit *CU)
   if (CUNode) {
     if (const auto &ETs = CUNode->getEnumTypes())
       AllEnumTypes.assign(ETs.begin(), ETs.end());
     if (const auto &RTs = CUNode->getRetainedTypes())
       AllRetainTypes.assign(RTs.begin(), RTs.end());
     if (const auto &GVs = CUNode->getGlobalVariables())
       AllGVs.assign(GVs.begin(), GVs.end());
     if (const auto &IMs = CUNode->getImportedEntities())
-      AllImportedModules.assign(IMs.begin(), IMs.end());
+      ImportedModules.assign(IMs.begin(), IMs.end());
     if (const auto &MNs = CUNode->getMacros())
       AllMacrosPerParent.insert({nullptr, {MNs.begin(), MNs.end()}});
   }
 }
 
 void DIBuilder::trackIfUnresolved(MDNode *N) {
   if (!N)
     return;
for (auto *SP : AllSubprograms)
     finalizeSubprogram(SP);
   for (auto *N : RetainValues)
     if (auto *SP = dyn_cast<DISubprogram>(N))
       finalizeSubprogram(SP);
 
   if (!AllGVs.empty())
     CUNode->replaceGlobalVariables(MDTuple::get(VMContext, AllGVs));
 
-  if (!AllImportedModules.empty())
+  if (!ImportedModules.empty())
     CUNode->replaceImportedEntities(MDTuple::get(
-        VMContext, SmallVector<Metadata *, 16>(AllImportedModules.begin(),
-                                               AllImportedModules.end())));
+        VMContext, SmallVector<Metadata *, 16>(ImportedModules.begin(),
+                                               ImportedModules.end())));
 
   for (const auto &I : AllMacrosPerParent) {
     // DIMacroNode's with nullptr parent are DICompileUnit direct children.
     if (!I.first) {
       CUNode->replaceMacros(MDTuple::get(VMContext, I.second.getArrayRef()));
       continue;
     }
     // Otherwise, it must be a temporary DIMacroFile that need to be resolved.
DICompileUnit *DIBuilder::createCompileUnit(
   trackIfUnresolved(CUNode);
   return CUNode;
 }
 
 static DIImportedEntity *
 createImportedModule(LLVMContext &C, dwarf::Tag Tag, DIScope *Context,
                      Metadata *NS, DIFile *File, unsigned Line, StringRef Name,
                      DINodeArray Elements,
-                     SmallVectorImpl<TrackingMDNodeRef> &AllImportedModules) {
+                     SmallVectorImpl<TrackingMDNodeRef> &ImportedModules) {
   if (Line)
     assert(File && "Source location has line number but no file");
   unsigned EntitiesCount = C.pImpl->DIImportedEntitys.size();
   auto *M = DIImportedEntity::get(C, Tag, Context, cast_or_null<DINode>(NS),
                                   File, Line, Name, Elements);
   if (EntitiesCount < C.pImpl->DIImportedEntitys.size())
     // A new Imported Entity was just added to the context.
     // Add it to the Imported Modules list.
-    AllImportedModules.emplace_back(M);
+    ImportedModules.emplace_back(M);
   return M;
 }
 
 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
                                                   DINamespace *NS, DIFile *File,
                                                   unsigned Line,
                                                   DINodeArray Elements) {
   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
                                 Context, NS, File, Line, StringRef(), Elements,
-                                AllImportedModules);
+                                getImportTrackingVector(Context));
 }
 
 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context,
                                                   DIImportedEntity *NS,
                                                   DIFile *File, unsigned Line,
                                                   DINodeArray Elements) {
   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
                                 Context, NS, File, Line, StringRef(), Elements,
-                                AllImportedModules);
+                                getImportTrackingVector(Context));
 }
 
 DIImportedEntity *DIBuilder::createImportedModule(DIScope *Context, DIModule *M,
                                                   DIFile *File, unsigned Line,
                                                   DINodeArray Elements) {
   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_module,
                                 Context, M, File, Line, StringRef(), Elements,
-                                AllImportedModules);
+                                getImportTrackingVector(Context));
 }
 
 DIImportedEntity *
 DIBuilder::createImportedDeclaration(DIScope *Context, DINode *Decl,
                                      DIFile *File, unsigned Line,
                                      StringRef Name, DINodeArray Elements) {
   // Make sure to use the unique identifier based metadata reference for
   // types that have one.
   return ::createImportedModule(VMContext, dwarf::DW_TAG_imported_declaration,
                                 Context, Decl, File, Line, Name, Elements,
-                                AllImportedModules);
+                                getImportTrackingVector(Context));
 }
 
 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
                               std::optional<DIFile::ChecksumInfo<StringRef>> CS,
                               std::optional<StringRef> Source) {
   return DIFile::get(VMContext, Filename, Directory, CS, Source);
 }
 

llvm/lib/IR/Verifier.cpp

if (auto *Params = N.getRawTemplateParams())
     visitTemplateParams(N, *Params);
   if (auto *S = N.getRawDeclaration())
     CheckDI(isa<DISubprogram>(S) && !cast<DISubprogram>(S)->isDefinition(),
             "invalid subprogram declaration", &N, S);
   if (auto *RawNode = N.getRawRetainedNodes()) {
     auto *Node = dyn_cast<MDTuple>(RawNode);
     CheckDI(Node, "invalid retained nodes list", &N, RawNode);
     for (Metadata *Op : Node->operands()) {
-      CheckDI(Op && (isa<DILocalVariable>(Op) || isa<DILabel>(Op)),
-              "invalid retained nodes, expected DILocalVariable or DILabel", &N,
-              Node, Op);
+      CheckDI(Op && (isa<DILocalVariable>(Op) || isa<DILabel>(Op) ||
+                     isa<DIImportedEntity>(Op)),
+              "invalid retained nodes, expected DILocalVariable, DILabel or "
+              "DIImportedEntity",
+              &N, Node, Op);
     }
   }
   CheckDI(!hasConflictingReferenceFlags(N.getFlags()),
           "invalid reference flags", &N);
 
   auto *Unit = N.getRawUnit();
   if (N.isDefinition()) {
     // Subprogram definitions (not part of the type hierarchy).

llvm/lib/Linker/IRMover.cpp

for (unsigned I = 0, E = SrcCompileUnits->getNumOperands(); I != E; ++I) {
     // If LLVM ever does more advanced optimizations on global variables
     // (removing/localizing write operations, for instance) that can track
     // through debug info, this decision may need to be revisited - but do so
     // with care when it comes to debug info size. Emitting small CUs containing
     // only a few imported entities into every destination module may be very
     // size inefficient.
     CU->replaceGlobalVariables(nullptr);
 
-    // Imported entities only need to be mapped in if they have local
-    // scope, as those might correspond to an imported entity inside a
-    // function being imported (any locally scoped imported entities that
-    // don't end up referenced by an imported function will not be emitted
-    // into the object). Imported entities not in a local scope
-    // (e.g. on the namespace) only need to be emitted by the originating
-    // module. Create a list of the locally scoped imported entities, and
-    // replace the source CUs imported entity list with the new list, so
-    // only those are mapped in.
-    // FIXME: Locally-scoped imported entities could be moved to the
-    // functions they are local to instead of listing them on the CU, and
-    // we would naturally only link in those needed by function importing.
-    SmallVector<TrackingMDNodeRef, 4> AllImportedModules;
-    bool ReplaceImportedEntities = false;
-    for (auto *IE : CU->getImportedEntities()) {
-      DIScope *Scope = IE->getScope();
-      assert(Scope && "Invalid Scope encoding!");
-      if (isa<DILocalScope>(Scope))
-        AllImportedModules.emplace_back(IE);
-      else
-        ReplaceImportedEntities = true;
-    }
-    if (ReplaceImportedEntities) {
-      if (!AllImportedModules.empty())
-        CU->replaceImportedEntities(MDTuple::get(
-            CU->getContext(),
-            SmallVector<Metadata *, 16>(AllImportedModules.begin(),
-                                        AllImportedModules.end())));
-      else
-        // If there were no local scope imported entities, we can map
-        // the whole list to nullptr.
-        CU->replaceImportedEntities(nullptr);
-    }
-  }
-}
 
 /// Insert all of the named MDNodes in Src into the Dest module.
 void IRLinker::linkNamedMDNodes() {
   const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
   for (const NamedMDNode &NMD : SrcM->named_metadata()) {
     // Don't link module flags here. Do them separately.
     if (&NMD == SrcModFlags)
       continue;

llvm/test/Bitcode/DIModule-fortran-external-module.ll

 ; RUN: llvm-as -o - %s | llvm-dis -o - | FileCheck %s
-; CHECK: DIImportedEntity(tag: DW_TAG_imported_module, scope: !2, entity: !11, file: !3, line: 2)
-; CHECK: DIModule(scope: !2, name: "external_module", isDecl: true)
+; CHECK: DIImportedEntity(tag: DW_TAG_imported_module, scope: !2, entity: ![[MOD:[0-9]+]], file: !3, line: 2)
+; CHECK: ![[MOD]] = !DIModule(scope: !2, name: "external_module", isDecl: true)
 
 ; ModuleID = 'em.f90'
 source_filename = "em.f90"
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 @external_module_mp_dummy_ = available_externally global float 0.000000e+00, align 8, !dbg !0
 @0 = internal unnamed_addr constant i32 2

llvm/test/Bitcode/upgrade-cu-locals.ll

+; Test moving of local imports from DICompileUnit's 'imports' to DISubprogram's 'retainedNodes'
+;
+; RUN: llvm-dis -o - %s.bc | FileCheck %s
+
+%"struct.ns::t1" = type { i8 }
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
+
+declare dso_local void @_Z3pinv() local_unnamed_addr
+
+define dso_local i32 @main() local_unnamed_addr !dbg !23 {
+entry:
+  call void @llvm.dbg.declare(metadata ptr undef, metadata !39, metadata !DIExpression()), !dbg !40
+  call void @_Z3pinv(), !dbg !42
+  ret i32 0, !dbg !43
+}
+
+define dso_local i32 @main2() local_unnamed_addr !dbg !29 {
+  ret i32 0
+}
+
+attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
+
+!llvm.dbg.cu = !{!0, !16}
+!llvm.ident = !{!33, !33}
+!llvm.module.flags = !{!34, !35, !36, !37, !38}
+
+; CHECK: !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !2,
+; CHECK: !2 = !{!3}
+; CHECK: !3 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !0, entity: !4,
+; CHECK: !4 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t4"
+
+; CHECK: !5 = !{}
+; CHECK: !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !7, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !5, nameTableKind: GNU)
+
+; CHECK: !14 = distinct !DISubprogram(name: "main", scope: !7, file: !7, line: 2, type: !15, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !18)
+; CHECK: !18 = !{!19}
+; CHECK: !19 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !20, entity: !23,
+; CHECK: !20 = !DILexicalBlock(scope: !21, file: !7, line: 7, column: 35)
+; CHECK: !21 = !DILexicalBlock(scope: !22, file: !7, line: 7, column: 35)
+; CHECK: !22 = !DILexicalBlock(scope: !14, file: !7, line: 7, column: 35)
+; CHECK: !23 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t5", scope: !20,
+
+; CHECK: !25 = distinct !DISubprogram(name: "f1", linkageName: "_Z2f1v", scope: !1, file: !1, line: 3, type: !26, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !28)
+; CHECK: !28 = !{!29, !32, !34}
+; CHECK: !29 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !25, entity: !30,
+; CHECK: !30 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1",
+; CHECK: !32 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !25, entity: !33,
+; CHECK: !33 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t2",
+; CHECK: !34 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !25, entity: !35,
+; CHECK: !35 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t3",
+
+; CHECK: !40 = distinct !DISubprogram(name: "main2", scope: !7, file: !7, line: 10, type: !15, scopeLine: 10, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !41)
+; CHECK: !41 = !{!42, !44}
+; CHECK: !42 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !40, entity: !43,
+; CHECK: !43 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t6"
+; CHECK: !44 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !40, entity: !45,
+; CHECK: !45 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t7",
+
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !2, nameTableKind: GNU)
+!1 = !DIFile(filename: "a.cpp", directory: "/")
+!2 = !{!3, !10, !12, !14}
+
+; Move t1 to DISubprogram f1
+!3 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !8, file: !1, line: 3)
+!4 = distinct !DISubprogram(name: "f1", linkageName: "_Z2f1v", scope: !1, file: !1, line: 3, type: !5, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !7)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{}
+!8 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1", scope: !9, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t1E")
+!9 = !DINamespace(name: "ns", scope: null)
+
+; Move t2 to DISubprogram f1
+!10 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !11, file: !1, line: 3)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t2", scope: !9, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t2E")
+
+; Move t3 to DISubprogram f1
+!12 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !13, file: !1, line: 3)
+!13 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t3", scope: !9, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t3E")
+
+; Leave t4 in CU
+!14 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !0, entity: !15, file: !1, line: 3)
+!15 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t4", scope: !0, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t4E")
+!16 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !17, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !18, nameTableKind: GNU)
+!17 = !DIFile(filename: "b.cpp", directory: "/")
+!18 = !{!19, !28, !31}
+
+; Move t5 to DISubprogram main
+!19 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !20, entity: !27, file: !1, line: 3)
+!20 = !DILexicalBlock(scope: !21, file: !17, line: 7, column: 35)
+!21 = !DILexicalBlock(scope: !22, file: !17, line: 7, column: 35)
+!22 = !DILexicalBlock(scope: !23, file: !17, line: 7, column: 35)
+!23 = distinct !DISubprogram(name: "main", scope: !17, file: !17, line: 2, type: !24, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !16, retainedNodes: !7)
+!24 = !DISubroutineType(types: !25)
+!25 = !{!26}
+!26 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!27 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t5", scope: !20, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t5E")
+
+; Move t6 to DISubprogram main2
+!28 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !29, entity: !30, file: !17, line: 3)
+!29 = distinct !DISubprogram(name: "main2", scope: !17, file: !17, line: 10, type: !24, scopeLine: 10, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !16, retainedNodes: !7)
+!30 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t6", scope: !29, file: !17, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t6E")
+
+; Move t7 to DISubprogram main2
+!31 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !29, entity: !32, file: !17, line: 3)
+!32 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t7", scope: !29, file: !17, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t7E")
+!33 = !{!"clang version 14.0.0"}
+!34 = !{i32 7, !"Dwarf Version", i32 4}
+!35 = !{i32 2, !"Debug Info Version", i32 3}
+!36 = !{i32 1, !"wchar_size", i32 4}
+!37 = !{i32 7, !"uwtable", i32 1}
+!38 = !{i32 7, !"frame-pointer", i32 2}
+!39 = !DILocalVariable(name: "v1", scope: !4, file: !1, line: 3, type: !8)
+!40 = !DILocation(line: 3, column: 37, scope: !4, inlinedAt: !41)
+!41 = distinct !DILocation(line: 3, column: 3, scope: !23)
+!42 = !DILocation(line: 3, column: 41, scope: !4, inlinedAt: !41)
+!43 = !DILocation(line: 4, column: 1, scope: !23)

llvm/test/CodeGen/Generic/DbgValueAggregate.ll

 
 attributes #0 = { "frame-pointer"="non-leaf" }
 attributes #1 = { nounwind readnone speculatable }
 
 !llvm.module.flags = !{!0}
 !llvm.dbg.cu = !{!1}
 
 !0 = !{i32 2, !"Debug Info Version", i32 3}
-!1 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !2, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, retainedTypes: !3, globals: !3, imports: !4)
+!1 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !2, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, retainedTypes: !3, globals: !3)
 !2 = !DIFile(filename: "input", directory: "/")
 !3 = !{}
 !4 = !{!5}
 !5 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !6, entity: !9, file: !2, line: 18)
-!6 = distinct !DISubprogram(name: "p", scope: !1, file: !2, line: 18, type: !7, isLocal: false, isDefinition: true, scopeLine: 18, isOptimized: false, unit: !1)
+!6 = distinct !DISubprogram(name: "p", scope: !1, file: !2, line: 18, type: !7, isLocal: false, isDefinition: true, scopeLine: 18, isOptimized: false, unit: !1, retainedNodes: !4)
 !7 = !DISubroutineType(cc: DW_CC_program, types: !8)
 !8 = !{null}
 !9 = !DIModule(scope: !1, name: "mod")
 !10 = !DILocalVariable(name: "localvar", scope: !11, file: !2, type: !12)
 !11 = !DILexicalBlock(scope: !6, file: !2, line: 18, column: 1)
 !12 = !DIBasicType(name: "complex", size: 64, align: 32, encoding: DW_ATE_complex_float)
 !13 = !DILocation(line: 0, scope: !11)

llvm/test/DebugInfo/Generic/import-inlined-declaration.ll

+; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump - | FileCheck --implicit-check-not "{{DW_TAG|NULL}}" %s
+
+; namespace ns {
+; inline __attribute__((always_inline))
+; void foo() { int a = 4; }
+; }
+;
+; void goo() {
+;   using ns::foo;
+;   foo();
+; }
+
+; Ensure that imported declarations reference the correct subprograms even if
+; those subprograms are inlined.
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_namespace
+; CHECK:     DW_AT_name     ("ns")
+; CHECK: [[FOO:0x.*]]:     DW_TAG_subprogram
+; CHECK:       DW_AT_name   ("foo")
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   DW_TAG_base_type
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name     ("goo")
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:       DW_AT_abstract_origin ([[FOO]]
+; CHECK:       DW_TAG_variable
+; CHECK:       NULL
+; CHECK:     DW_TAG_imported_declaration
+; CHECK:       DW_AT_import ([[FOO]])
+; CHECK:     NULL
+; CHECK:   NULL
+
+; Function Attrs: mustprogress noinline optnone uwtable
+define dso_local void @_Z3goov() !dbg !4 {
+entry:
+  %a.i = alloca i32, align 4
+  call void @llvm.dbg.declare(metadata i32* %a.i, metadata !16, metadata !DIExpression()), !dbg !18
+  store i32 4, i32* %a.i, align 4, !dbg !18
+  ret void, !dbg !20
+}
+
+; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!10, !11, !12, !13, !14}
+!llvm.ident = !{!15}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "imported-inlined-declaration.cpp", directory: "")
+!2 = !{!3}
+!3 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !8, file: !1, line: 7)
+!4 = distinct !DISubprogram(name: "goo", linkageName: "_Z3goov", scope: !1, file: !1, line: 6, type: !5, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{}
+!8 = distinct !DISubprogram(name: "foo", linkageName: "_ZN2ns3fooEv", scope: !9, file: !1, line: 3, type: !5, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !7)
+!9 = !DINamespace(name: "ns", scope: null)
+!10 = !{i32 7, !"Dwarf Version", i32 4}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"wchar_size", i32 4}
+!13 = !{i32 7, !"uwtable", i32 1}
+!14 = !{i32 7, !"frame-pointer", i32 2}
+!15 = !{!"clang version 14.0.0"}
+!16 = !DILocalVariable(name: "a", scope: !8, file: !1, line: 3, type: !17)
+!17 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!18 = !DILocation(line: 3, column: 18, scope: !8, inlinedAt: !19)
+!19 = distinct !DILocation(line: 8, column: 2, scope: !4)
+!20 = !DILocation(line: 9, column: 1, scope: !4)

llvm/test/DebugInfo/Generic/imported-name-inlined.ll

 ; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck --implicit-check-not "{{DW_TAG|NULL}}" %s
 
 ; Generated from the following source:
 ; namespace ns {
 ; void f();
 ; }
 ; inline __attribute__((always_inline)) void f1() {
 ;   using ns::f;
 ;   f();
 ; }
 ; void f2() { f1(); }
 
 ; Ensure that top level imported declarations don't produce an extra degenerate
 ; concrete subprogram definition.
 
-; FIXME: imported entities should only be emitted to the abstract origin if one is present
-
 ; CHECK: DW_TAG_compile_unit
 ; CHECK:   DW_TAG_subprogram
 ; CHECK:     DW_AT_name ("f1")
 ; CHECK:     DW_TAG_imported_declaration
 ; CHECK:     NULL
-; CHECK:   DW_TAG_namespace
-; CHECK:     DW_TAG_subprogram
-; CHECK:     NULL
 ; CHECK:   DW_TAG_subprogram
 ; CHECK:     DW_AT_name ("f2")
 ; CHECK:     DW_TAG_inlined_subroutine
-; CHECK:       DW_TAG_imported_declaration
-; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   DW_TAG_namespace
+; CHECK:     DW_TAG_subprogram
 ; CHECK:     NULL
 ; CHECK:   NULL
 
 ; Function Attrs: noinline
 define void @_Z2f2v() noinline !dbg !14 {
 entry:
   call void @_ZN2ns1fEv(), !dbg !15
   ret void, !dbg !17
 }
 
 declare void @_ZN2ns1fEv()
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!10, !11, !12}
 !llvm.ident = !{!13}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 309061) (llvm/trunk 309076)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, imports: !3)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 309061) (llvm/trunk 309076)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
 !1 = !DIFile(filename: "imported-name-inlined.cpp", directory: "/usr/local/google/home/blaikie/dev/scratch")
 !2 = !{}
 !3 = !{!4}
 !4 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !5, entity: !8, file: !1, line: 5)
-!5 = distinct !DISubprogram(name: "f1", linkageName: "_Z2f1v", scope: !1, file: !1, line: 4, type: !6, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!5 = distinct !DISubprogram(name: "f1", linkageName: "_Z2f1v", scope: !1, file: !1, line: 4, type: !6, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !3)
 !6 = !DISubroutineType(types: !7)
 !7 = !{null}
 !8 = !DISubprogram(name: "f", linkageName: "_ZN2ns1fEv", scope: !9, file: !1, line: 2, type: !6, isLocal: false, isDefinition: false, flags: DIFlagPrototyped, isOptimized: false)
 !9 = !DINamespace(name: "ns", scope: null)
 !10 = !{i32 2, !"Dwarf Version", i32 4}
 !11 = !{i32 2, !"Debug Info Version", i32 3}
 !12 = !{i32 1, !"wchar_size", i32 4}
 !13 = !{!"clang version 6.0.0 (trunk 309061) (llvm/trunk 309076)"}
 !14 = distinct !DISubprogram(name: "f2", linkageName: "_Z2f2v", scope: !1, file: !1, line: 8, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 !15 = !DILocation(line: 6, column: 3, scope: !5, inlinedAt: !16)
 !16 = distinct !DILocation(line: 8, column: 13, scope: !14)
 !17 = !DILocation(line: 8, column: 19, scope: !14)

llvm/test/DebugInfo/Generic/namespace.ll

 ; CHECK:   DW_AT_MIPS_linkage_name
 ; CHECK:   DW_AT_name ("f1")
 ; CHECK: [[FUNC1:.*]]: DW_TAG_subprogram
 ; CHECK:   DW_AT_MIPS_linkage_name
 ; CHECK:   DW_AT_name ("f1")
 ; CHECK:   DW_TAG_formal_parameter
 ; CHECK:   NULL
 
+; CHECK: [[FUNC_FWD:0x[0-9a-f]*]]:{{.*}}DW_TAG_subprogram
+; CHECK:   DW_AT_name ("func_fwd")
+; CHECK-NOT: DW_AT_declaration
+
 ; CHECK: [[BAZ:0x[0-9a-f]*]]:{{.*}}DW_TAG_typedef
 ; CHECK:   DW_AT_name ("baz")
 
 ; CHECK: [[VAR_DECL:0x[0-9a-f]*]]:{{.*}}DW_TAG_variable
 ; CHECK:   DW_AT_name ("var_decl")
 ; CHECK:   DW_AT_declaration
 
 ; CHECK: [[FUNC_DECL:0x[0-9a-f]*]]:{{.*}}DW_TAG_subprogram
 ; CHECK:   DW_AT_name ("func_decl")
 ; CHECK:   DW_AT_declaration
-
-; CHECK: [[FUNC_FWD:0x[0-9a-f]*]]:{{.*}}DW_TAG_subprogram
-; CHECK:   DW_AT_name ("func_fwd")
-; CHECK-NOT: DW_AT_declaration
 ; CHECK: NULL
 
 ; CHECK: DW_TAG_imported_module
 ; CHECK:   DW_AT_decl_file ([[F2:.*]])
 ; CHECK:   DW_AT_decl_line (15)
 ; CHECK:   DW_AT_import ([[NS2]])
 ; CHECK: DW_TAG_imported_declaration
 ; CHECK: NULL
 
 ; CHECK: DW_TAG_base_type
 ; CHECK: DW_TAG_subprogram
 
 ; CHECK: DW_TAG_subprogram
 ; CHECK:   DW_AT_MIPS_linkage_name
 ; CHECK:   DW_AT_name ("func")
 ; CHECK:   DW_TAG_formal_parameter
+; CHECK:   DW_TAG_lexical_block
+; CHECK:     DW_TAG_imported_module
+; CHECK:       DW_AT_decl_file ([[F2]])
+; CHECK:       DW_AT_decl_line (23)
+; CHECK:       DW_AT_import {{.*}}
+; CHECK:     NULL
 ; CHECK:   DW_TAG_imported_module
 ; CHECK:     DW_AT_decl_file ([[F2:.*]])
 ; CHECK:     DW_AT_decl_line (26)
 ; CHECK:     DW_AT_import ([[NS1]])
 ; CHECK:   DW_TAG_imported_declaration
 ; CHECK:     DW_AT_decl_file ([[F2]])
 ; CHECK:     DW_AT_decl_line (27)
 ; CHECK:     DW_AT_import ([[FOO]])

 ; CHECK:   DW_TAG_imported_declaration
 ; CHECK:     DW_AT_decl_file ([[F2]])
 ; CHECK:     DW_AT_decl_line (36)
 ; CHECK:     DW_AT_import ([[VAR_FWD]])
 ; CHECK:   DW_TAG_imported_declaration
 ; CHECK:     DW_AT_decl_file ([[F2]])
 ; CHECK:     DW_AT_decl_line (37)
 ; CHECK:     DW_AT_import ([[FUNC_FWD]])
-; CHECK:   DW_TAG_lexical_block
-; CHECK:     DW_TAG_imported_module
-; CHECK:       DW_AT_decl_file ([[F2]])
-; CHECK:       DW_AT_decl_line (23)
-; CHECK:       DW_AT_import {{.*}}
-; CHECK:     NULL
 ; CHECK:   NULL
 
 ; CHECK: DW_TAG_subprogram
 ; CHECK: DW_TAG_imported_module
 ; CHECK:   DW_AT_decl_file ([[F2:.*]])
 ; CHECK:   DW_AT_decl_line (18)
 ; CHECK:   DW_AT_import ([[NS1]])
 ; CHECK: DW_TAG_imported_declaration

 !13 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !14 = distinct !DISubprogram(name: "f1", linkageName: "_ZN1A1B2f1Ei", line: 4, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 4, file: !5, scope: !6, type: !15, retainedNodes: !2)
 !15 = !DISubroutineType(types: !16)
 !16 = !{null, !13}
 !17 = distinct !DISubprogram(name: "__cxx_global_var_init", line: 20, isLocal: true, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 20, file: !5, scope: !18, type: !19, retainedNodes: !2)
 !18 = !DIFile(filename: "foo.cpp", directory: "/tmp")
 !19 = !DISubroutineType(types: !20)
 !20 = !{null}
-!21 = distinct !DISubprogram(name: "func", linkageName: "_Z4funcb", line: 21, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 21, file: !5, scope: !18, type: !22, retainedNodes: !2)
+!21 = distinct !DISubprogram(name: "func", linkageName: "_Z4funcb", line: 21, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 21, file: !5, scope: !18, type: !22, retainedNodes: !77)
 !22 = !DISubroutineType(types: !23)
 !23 = !{!13, !24}
 !24 = !DIBasicType(tag: DW_TAG_base_type, name: "bool", size: 8, align: 8, encoding: DW_ATE_boolean)
 !25 = distinct !DISubprogram(name: "__cxx_global_var_init1", line: 44, isLocal: true, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 44, file: !5, scope: !18, type: !19, retainedNodes: !2)
 !26 = distinct !DISubprogram(name: "func_fwd", linkageName: "_ZN1A1B8func_fwdEv", line: 47, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 47, file: !5, scope: !6, type: !19, retainedNodes: !2)
 !27 = distinct !DISubprogram(name: "", linkageName: "_GLOBAL__sub_I_debug_info_namespace.cpp", isLocal: true, isDefinition: true, flags: DIFlagArtificial, isOptimized: false, unit: !0, file: !1, scope: !28, type: !29, retainedNodes: !2)
 !28 = !DIFile(filename: "debug-info-namespace.cpp", directory: "/tmp")
 !29 = !DISubroutineType(types: !2)
 !30 = !{!131, !132}
 !31 = !DIGlobalVariable(name: "i", linkageName: "_ZN1A1B1iE", line: 20, isLocal: false, isDefinition: true, scope: !6, file: !18, type: !13)
 !32 = !DIGlobalVariable(name: "var_fwd", linkageName: "_ZN1A1B7var_fwdE", line: 44, isLocal: false, isDefinition: true, scope: !6, file: !18, type: !13)
-!33 = !{!34, !35, !36, !37, !40, !41, !42, !43, !44, !45, !47, !48, !49, !51, !54, !55, !56}
+!33 = !{!34, !35, !36, !56}
 !34 = !DIImportedEntity(tag: DW_TAG_imported_module, file: !5, line: 15, scope: !7, entity: !6)
 !35 = !DIImportedEntity(tag: DW_TAG_imported_module, file: !5, line: 18, scope: !0, entity: !7)
 !36 = !DIImportedEntity(tag: DW_TAG_imported_declaration, file: !5, line: 19, name: "E", scope: !0, entity: !7)
 !37 = !DIImportedEntity(tag: DW_TAG_imported_module, file: !5, line: 23, scope: !38, entity: !6)
 !38 = distinct !DILexicalBlock(line: 22, column: 10, file: !5, scope: !39)
 !39 = distinct !DILexicalBlock(line: 22, column: 7, file: !5, scope: !21)
 !40 = !DIImportedEntity(tag: DW_TAG_imported_module, file: !5, line: 26, scope: !21, entity: !7)
 !41 = !DIImportedEntity(tag: DW_TAG_imported_declaration, file: !5, line: 27, scope: !21, entity: !4)

 !68 = !DILocation(line: 22, column: 7, scope: !21)
 !69 = !DILocation(line: 24, column: 5, scope: !38)
 !70 = !DILocation(line: 38, column: 3, scope: !21)
 !71 = !DILocation(line: 39, column: 1, scope: !21)
 !72 = !DILocation(line: 44, column: 15, scope: !25)
 !73 = !DILocation(line: 47, column: 21, scope: !26)
 !74 = !DILocation(line: 0, scope: !75)
 !75 = !DILexicalBlockFile(discriminator: 0, file: !5, scope: !27)
+!77 = !{!37, !40, !41, !42, !43, !44, !45, !47, !48, !49, !51, !54, !55}
 !131 = !DIGlobalVariableExpression(var: !31, expr: !DIExpression())
 !132 = !DIGlobalVariableExpression(var: !32, expr: !DIExpression())

llvm/test/DebugInfo/Generic/split-dwarf-local-import.ll

+; RUN: %llc_dwarf -O1 -filetype=obj --mtriple=x86_64-unknown-linux-gnu -split-dwarf-file=%t.dwo < %s | llvm-dwarfdump -debug-info - | FileCheck %s --implicit-check-not "{{DW_TAG|NULL}}"
+
+; CHECK-LABEL: debug_info contents
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_AT_GNU_dwo_name
+; CHECK:   DW_AT_GNU_dwo_id
+; CHECK:   DW_TAG_subprogram
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:     NULL
+; CHECK:   NULL
+
+; CHECK-LABEL: debug_info.dwo contents
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_TAG_imported_declaration
+; CHECK:     NULL
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:     NULL
+; CHECK:   DW_TAG_namespace
+; CHECK:     DW_TAG_structure_type
+; CHECK:     NULL
+; CHECK:   DW_TAG_base_type
+; CHECK:   NULL
+
+%"struct.ns::t1" = type { i8 }
+
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+declare dso_local void @_Z3pinv() local_unnamed_addr
+
+define dso_local i32 @main() local_unnamed_addr !dbg !18 {
+entry:
+  call void @llvm.dbg.declare(metadata %"struct.ns::t1"* undef, metadata !22, metadata !DIExpression()), !dbg !23
+  call void @_Z3pinv(), !dbg !25
+  ret i32 0, !dbg !26
+}
+
+!llvm.dbg.cu = !{!0, !10}
+!llvm.ident = !{!12, !12}
+!llvm.module.flags = !{!13, !14, !15, !16, !17}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: true, nameTableKind: GNU)
+!1 = !DIFile(filename: "a.cpp", directory: "/")
+!2 = !{!3}
+!3 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !8, file: !1, line: 3)
+!4 = distinct !DISubprogram(name: "f1", linkageName: "_Z2f1v", scope: !1, file: !1, line: 3, type: !5, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null}
+!7 = !{}
+!8 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "t1", scope: !9, file: !1, line: 1, size: 8, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTSN2ns2t1E")
+!9 = !DINamespace(name: "ns", scope: null)
+!10 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !11, producer: "clang version 14.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: true, nameTableKind: GNU)
+!11 = !DIFile(filename: "b.cpp", directory: "/")
+!12 = !{!"clang version 14.0.0"}
+!13 = !{i32 7, !"Dwarf Version", i32 4}
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!15 = !{i32 1, !"wchar_size", i32 4}
+!16 = !{i32 7, !"uwtable", i32 1}
+!17 = !{i32 7, !"frame-pointer", i32 2}
+!18 = distinct !DISubprogram(name: "main", scope: !11, file: !11, line: 2, type: !19, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !10, retainedNodes: !7)
+!19 = !DISubroutineType(types: !20)
+!20 = !{!21}
+!21 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!22 = !DILocalVariable(name: "v1", scope: !4, file: !1, line: 3, type: !8)
+!23 = !DILocation(line: 3, column: 37, scope: !4, inlinedAt: !24)
+!24 = distinct !DILocation(line: 3, column: 3, scope: !18)
+!25 = !DILocation(line: 3, column: 41, scope: !4, inlinedAt: !24)
+!26 = !DILocation(line: 4, column: 1, scope: !18)

llvm/test/DebugInfo/Generic/split-dwarf-local-import2.ll

+; RUN: %llc_dwarf --mtriple=x86_64-unknown-linux-gnu -split-dwarf-file=%t.dwo < %s | FileCheck %s
+
+; Ensure function-local DW_TAG_imported_declaration get skipped if its parent subprogram was not emitted.
+; CHECK-NOT: DW_TAG_imported_declaration
+
+define void @f1() !dbg !13 {
+lbl:
+  ret void, !dbg !16
+}
+
+define void @f2() !dbg !22 {
+lbl:
+  ret void, !dbg !23
+}
+
+!llvm.dbg.cu = !{!0, !2, !10}
+!llvm.module.flags = !{!12}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, emissionKind: FullDebug)
+!1 = !DIFile(filename: "a.cc", directory: "")
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, emissionKind: FullDebug)
+!3 = !DIFile(filename: "b.cc", directory: "")
+!4 = !{!5}
+!5 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !6, entity: !7)
+!6 = !DISubprogram(scope: null, spFlags: DISPFlagOptimized, retainedNodes: !4)
+!7 = !DINamespace(scope: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{}
+!10 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !11, emissionKind: FullDebug)
+!11 = !DIFile(filename: "c.cc", directory: "")
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = distinct !DISubprogram(scope: null, type: !8, spFlags: DISPFlagDefinition, unit: !0)
+!16 = !DILocation(line: 0, scope: !17, inlinedAt: !18)
+!17 = distinct !DISubprogram(scope: null, unit: !10)
+!18 = !DILocation(line: 0, scope: !21)
+!21 = !DILexicalBlockFile(scope: !13, discriminator: 0)
+!22 = distinct !DISubprogram(scope: null, type: !8, spFlags: DISPFlagDefinition, unit: !0)
+!23 = !DILocation(line: 0, scope: !24, inlinedAt: !25)
+!24 = distinct !DISubprogram(scope: null, unit: !2)
+!25 = !DILocation(line: 0, scope: !22)

llvm/test/DebugInfo/Generic/split-dwarf-local-import3.ll

+; UNSUPPORTED: target={{.*}}-aix{{.*}}
+; RUN: %llc_dwarf --mtriple=x86_64-unknown-linux-gnu -O1 -filetype=obj -split-dwarf-file=%t.dwo < %s \
+; RUN:   | llvm-dwarfdump -debug-info -                           \
+; RUN:   | FileCheck %s --implicit-check-not "{{DW_TAG|NULL}}"
+
+; Ensure that the imported entity 'nn::A' gets emitted in 'foo()'s abstract tree
+; in the destination (where 'foo()' was inlined) compile unit.
+
+; CHECK-LABEL: .debug_info contents
+; CHECK: DW_TAG_skeleton_unit
+; CHECK:   DW_AT_dwo_name
+
+; CHECK-LABEL: .debug_info.dwo contents:
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_AT_name ("test.cpp")
+; CHECK:   DW_AT_dwo_name
+
+; CHECK:   [[ABSTRACT_FOO:0x[0-9a-f]+]]: DW_TAG_subprogram
+; CHECK:     DW_AT_name ("foo")
+; CHECK:     DW_TAG_imported_declaration
+; CHECK:       DW_AT_import  ([[A:0x[0-9a-f]+]])
+; CHECK:     NULL
+
+; CHECK:   DW_TAG_base_type
+; CHECK:     DW_AT_name ("int")
+
+; CHECK:   DW_TAG_subprogram
+; CHECK:     DW_AT_name ("main")
+; CHECK:     DW_TAG_inlined_subroutine
+; CHECK:       DW_AT_abstract_origin ([[ABSTRACT_FOO]] "_Z3foov")
+; CHECK:     NULL
+
+; CHECK:   DW_TAG_namespace
+; CHECK:     DW_AT_name ("nn")
+; CHECK:     [[A]]: DW_TAG_variable
+; CHECK:       DW_AT_name ("A")
+; CHECK:     NULL
+; CHECK:   NULL
+
+define dso_local noundef i32 @main() local_unnamed_addr !dbg !20 {
+entry:
+  ret i32 42, !dbg !21
+}
+
+!llvm.dbg.cu = !{!0, !2}
+!llvm.module.flags = !{!13, !14}
+!llvm.ident = !{!19, !19}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 15.0.0", isOptimized: true, runtimeVersion: 0, splitDebugFilename: "test.dwo", emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: GNU)
+!1 = !DIFile(filename: "test.cpp", directory: "/", checksumkind: CSK_MD5, checksum: "e7c2808ee27614e496499d55e4b37962")
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 15.0.0", isOptimized: true, runtimeVersion: 0, splitDebugFilename: "cu1.dwo", emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: GNU)
+!3 = !DIFile(filename: "cu1.cpp", directory: "/", checksumkind: CSK_MD5, checksum: "c0b84240ef5682b87083b33cf9038171")
+!4 = !{!5}
+!5 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !6, entity: !11, file: !3, line: 5)
+!6 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !3, file: !3, line: 5, type: !7, scopeLine: 5, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !4)
+!7 = !DISubroutineType(types: !8)
+!8 = !{!9}
+!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!10 = !{}
+!11 = distinct !DIGlobalVariable(name: "A", linkageName: "_ZN2nn1AE", scope: !12, file: !3, line: 2, type: !9, isLocal: false, isDefinition: true)
+!12 = !DINamespace(name: "nn", scope: null)
+!13 = !{i32 7, !"Dwarf Version", i32 5}
+!14 = !{i32 2, !"Debug Info Version", i32 3}
+!19 = !{!"clang version 15.0.0"}
+!20 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 3, type: !7, scopeLine: 3, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !10)
+!21 = !DILocation(line: 4, column: 3, scope: !6, inlinedAt: !22)
+!22 = !DILocation(line: 4, column: 3, scope: !20)

llvm/test/DebugInfo/Generic/verifier-invalid-disubprogram.ll

 ; CHECK: invalid subprogram declaration
 define void @invalid_subprogram_declaration() !dbg !9 { ret void }
 !9 = distinct !DISubprogram(declaration: !0)
 
 ; CHECK: invalid retained nodes list
 define void @invalid_retained_nodes_list() !dbg !10 { ret void }
 !10 = distinct !DISubprogram(retainedNodes: !0)
 
-; CHECK: invalid retained nodes, expected DILocalVariable or DILabel
+; CHECK: invalid retained nodes, expected DILocalVariable, DILabel or DIImportedEntity
 define void @invalid_retained_nodes_expected() !dbg !11 { ret void }
 !11 = distinct !DISubprogram(retainedNodes: !{!0})
 
 ; CHECK: invalid reference flags
 define void @invalid_reference_flags_reference() !dbg !12 { ret void }
 !12 = distinct !DISubprogram(flags: DIFlagLValueReference | DIFlagRValueReference)
 
 ; CHECK: invalid reference flags

llvm/test/DebugInfo/X86/dimodule-external-fortran.ll

 !omp_offload.info = !{}
 
 !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
 !1 = distinct !DIGlobalVariable(name: "dummy", linkageName: "external_module_mp_dummy_", scope: !2, file: !3, line: 1, type: !14, isLocal: false, isDefinition: true)
 !2 = distinct !DISubprogram(name: "use_external_module", linkageName: "MAIN__", scope: !3, file: !3, line: 1, type: !4, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !6, retainedNodes: !12)
 !3 = !DIFile(filename: "em.f90", directory: "tests")
 !4 = !DISubroutineType(types: !5)
 !5 = !{null}
-!6 = distinct !DICompileUnit(language: DW_LANG_Fortran95, file: !3, producer: "Intel(R) Fortran 21.0-2165", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !7, globals: !8, imports: !9, splitDebugInlining: false, nameTableKind: None)
+!6 = distinct !DICompileUnit(language: DW_LANG_Fortran95, file: !3, producer: "Intel(R) Fortran 21.0-2165", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !7, globals: !8, splitDebugInlining: false, nameTableKind: None)
 !7 = !{}
 !8 = !{!0}
-!9 = !{!10}
+!9 = !{}
 !10 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !2, entity: !11, file: !3, line: 2)
 !11 = !DIModule(scope: !2, name: "external_module", isDecl: true)
-!12 = !{!13}
+!12 = !{!10, !13}
 !13 = !DILocalVariable(name: "x", scope: !2, file: !3, line: 5, type: !14)
 !14 = !DIBasicType(name: "REAL*4", size: 32, encoding: DW_ATE_float)
 !15 = !{i32 2, !"Debug Info Version", i32 3}
 !16 = !{i32 2, !"Dwarf Version", i32 4}
 !17 = !DILocation(line: 5, column: 12, scope: !2)
 !18 = !DILocation(line: 1, column: 9, scope: !2)
 !19 = !DILocation(line: 6, column: 4, scope: !2)
 !20 = !DILocation(line: 6, column: 12, scope: !2)
 !21 = !DILocation(line: 8, column: 1, scope: !2)

llvm/test/DebugInfo/X86/dwarfdump-DIImportedEntity_elements.ll

 
 !llvm.module.flags = !{!21, !22}
 !llvm.dbg.cu = !{!4}
 
 !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
 !1 = distinct !DIGlobalVariable(name: "var1", scope: !2, file: !3, line: 2, type: !9, isLocal: false, isDefinition: true)
 !2 = !DIModule(scope: !4, name: "mymod", file: !3, line: 1)
 !3 = !DIFile(filename: "DIImportedEntity_elements.f90", directory: "/tmp")
-!4 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !3, producer: " F90 Flang - 1.5 2017-05-01", isOptimized: false, flags: "'+flang usemodulealias.f90 -g -S -emit-llvm'", runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !12, nameTableKind: None)
+!4 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !3, producer: " F90 Flang - 1.5 2017-05-01", isOptimized: false, flags: "'+flang usemodulealias.f90 -g -S -emit-llvm'", runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, nameTableKind: None)
 !5 = !{}
 !6 = !{!0, !7, !10}
 !7 = !DIGlobalVariableExpression(var: !8, expr: !DIExpression(DW_OP_plus_uconst, 4))
 !8 = distinct !DIGlobalVariable(name: "var2", scope: !2, file: !3, line: 3, type: !9, isLocal: false, isDefinition: true)
 !9 = !DIBasicType(name: "integer", size: 32, align: 32, encoding: DW_ATE_signed)
 !10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression(DW_OP_plus_uconst, 8))
 !11 = distinct !DIGlobalVariable(name: "var3", scope: !2, file: !3, line: 4, type: !9, isLocal: false, isDefinition: true)
 !12 = !{!13}
 !13 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !14, entity: !2, file: !3, line: 10, elements: !19)
-!14 = distinct !DISubprogram(name: "use_renamed", scope: !15, file: !3, line: 10, type: !18, scopeLine: 10, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition, unit: !4)
+!14 = distinct !DISubprogram(name: "use_renamed", scope: !15, file: !3, line: 10, type: !18, scopeLine: 10, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition, unit: !4, retainedNodes: !12)
 !15 = distinct !DISubprogram(name: "main", scope: !4, file: !3, line: 7, type: !16, scopeLine: 7, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagMainSubprogram, unit: !4)
 !16 = !DISubroutineType(cc: DW_CC_program, types: !17)
 !17 = !{null}
 !18 = !DISubroutineType(types: !17)
 !19 = !{!20}
 !20 = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "var4", scope: !14, entity: !1, file: !3, line: 10)
 !21 = !{i32 2, !"Dwarf Version", i32 4}
 !22 = !{i32 2, !"Debug Info Version", i32 3}
 !23 = !DILocation(line: 8, column: 1, scope: !15)
 !24 = !DILocation(line: 9, column: 1, scope: !15)
 !25 = !DILocation(line: 13, column: 1, scope: !14)

llvm/test/DebugInfo/X86/fission-inline.ll

 
 attributes #0 = { uwtable "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
 attributes #1 = { "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!22, !23}
 !llvm.ident = !{!24}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.6.0 ", isOptimized: false, splitDebugFilename: "fission-inline.dwo", emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !3, globals: !2, imports: !18)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.6.0 ", isOptimized: false, splitDebugFilename: "fission-inline.dwo", emissionKind: FullDebug, file: !1, enums: !2, retainedTypes: !3, globals: !2)
 !1 = !DIFile(filename: "fission-inline.cpp", directory: "/tmp/dbginfo")
 !2 = !{}
 !3 = !{!4}
 !4 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo", line: 1, size: 8, align: 8, file: !1, elements: !5, identifier: "_ZTS3foo")
 !5 = !{!6}
 !6 = !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 4, isLocal: false, isDefinition: false, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 4, file: !1, scope: !4, type: !7)
 !7 = !DISubroutineType(types: !8)
 !8 = !{null, null}
-!10 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 15, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 15, file: !1, scope: !4, type: !7, declaration: !6, retainedNodes: !2)
+!10 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 15, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 15, file: !1, scope: !4, type: !7, declaration: !6, retainedNodes: !18)
 !11 = distinct !DISubprogram(name: "f2<int>", linkageName: "_ZN3foo2f2IiEEvv", line: 10, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 10, file: !1, scope: !4, type: !12, templateParams: !14, declaration: !17, retainedNodes: !2)
 !12 = !DISubroutineType(types: !13)
 !13 = !{null}
 !14 = !{!15}
 !15 = !DITemplateTypeParameter(name: "T", type: !16)
 !16 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !17 = !DISubprogram(name: "f2<int>", linkageName: "_ZN3foo2f2IiEEvv", line: 10, isLocal: false, isDefinition: false, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 10, file: !1, scope: !4, type: !12, templateParams: !14)
 !18 = !{!19}

llvm/test/DebugInfo/X86/fission-local-import.ll

 entry:
   ret void, !dbg !13
 }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!9, !10, !11}
 !llvm.ident = !{!12}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 349508) (llvm/trunk 349520)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, imports: !3, nameTableKind: None)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (trunk 349508) (llvm/trunk 349520)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
 !1 = !DIFile(filename: "test.cpp", directory: "/usr/local/google/home/blaikie/dev/scratch")
 !2 = !{}
 !3 = !{!4}
 !4 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !5, entity: !8, file: !1, line: 2)
-!5 = distinct !DISubprogram(name: "test", linkageName: "_Z4testv", scope: !1, file: !1, line: 2, type: !6, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!5 = distinct !DISubprogram(name: "test", linkageName: "_Z4testv", scope: !1, file: !1, line: 2, type: !6, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !3)
 !6 = !DISubroutineType(types: !7)
 !7 = !{null}
 !8 = !DINamespace(name: "ns1", scope: null)
 !9 = !{i32 2, !"Dwarf Version", i32 4}
 !10 = !{i32 2, !"Debug Info Version", i32 3}
 !11 = !{i32 1, !"wchar_size", i32 4}
 !12 = !{!"clang version 8.0.0 (trunk 349508) (llvm/trunk 349520)"}
 !13 = !DILocation(line: 2, column: 36, scope: !5)
 

llvm/test/DebugInfo/X86/fission-no-inline-gsym.ll

 
 attributes #0 = { uwtable "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
 attributes #1 = { "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!22, !23}
 !llvm.ident = !{!24}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.6.0 ", isOptimized: false, splitDebugFilename: "fission-inline.dwo",  emissionKind: FullDebug, splitDebugInlining: false, file: !1, enums: !2, retainedTypes: !3, globals: !2, imports: !18)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.6.0 ", isOptimized: false, splitDebugFilename: "fission-inline.dwo",  emissionKind: FullDebug, splitDebugInlining: false, file: !1, enums: !2, retainedTypes: !3, globals: !2)
 !1 = !DIFile(filename: "fission-inline.cpp", directory: "")
 !2 = !{}
 !3 = !{!4}
 !4 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo", line: 1, size: 8, align: 8, file: !1, elements: !5, identifier: "_ZTS3foo")
 !5 = !{!6}
 !6 = !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 4, isLocal: false, isDefinition: false, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 4, file: !1, scope: !4, type: !7)
 !7 = !DISubroutineType(types: !8)
 !8 = !{null, null}
-!10 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 15, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 15, file: !1, scope: !4, type: !7, declaration: !6, retainedNodes: !2)
+!10 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ez", line: 15, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 15, file: !1, scope: !4, type: !7, declaration: !6, retainedNodes: !18)
 !11 = distinct !DISubprogram(name: "f2<int>", linkageName: "_ZN3foo2f2IiEEvv", line: 10, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 10, file: !1, scope: !4, type: !12, templateParams: !14, declaration: !17, retainedNodes: !2)
 !12 = !DISubroutineType(types: !13)
 !13 = !{null}
 !14 = !{!15}
 !15 = !DITemplateTypeParameter(name: "T", type: !16)
 !16 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !17 = !DISubprogram(name: "f2<int>", linkageName: "_ZN3foo2f2IiEEvv", line: 10, isLocal: false, isDefinition: false, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 10, file: !1, scope: !4, type: !12, templateParams: !14)
 !18 = !{!19}

llvm/test/DebugInfo/X86/lexical-block-file-inline.ll

 attributes #0 = { alwaysinline nounwind }
 attributes #1 = { nounwind readnone }
 attributes #2 = { nounwind }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!15, !16}
 !llvm.ident = !{!17}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 264349)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, imports: !10)
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.9.0 (trunk 264349)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2)
 !1 = !DIFile(filename: "test.cpp", directory: "/")
 !2 = !{}
-!4 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!4 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !10)
 !5 = !DISubroutineType(types: !6)
 !6 = !{!7}
 !7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !8 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !9, file: !9, line: 6, type: !5, isLocal: false, isDefinition: true, scopeLine: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 !9 = !DIFile(filename: "test.h", directory: "/")
 !10 = !{!11}
 !11 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !12, entity: !14, file: !1, line: 1)
 !12 = !DILexicalBlockFile(scope: !13, file: !9, discriminator: 0)

llvm/test/DebugInfo/X86/namelist2.ll

 
 !llvm.module.flags = !{!19, !20}
 !llvm.dbg.cu = !{!4}
 
 !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
 !1 = distinct !DIGlobalVariable(name: "aa", scope: !2, file: !3, line: 2, type: !9, isLocal: false, isDefinition: true)
 !2 = !DIModule(scope: !4, name: "mm", file: !3, line: 1)
 !3 = !DIFile(filename: "namelist2.f90", directory: "/dir")
-!4 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !3, producer: " F90 Flang - 1.5 2017-05-01", isOptimized: false, flags: "'+flang -g namelist2.f90 -S -emit-llvm'", runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !14, nameTableKind: None)
+!4 = distinct !DICompileUnit(language: DW_LANG_Fortran90, file: !3, producer: " F90 Flang - 1.5 2017-05-01", isOptimized: false, flags: "'+flang -g namelist2.f90 -S -emit-llvm'", runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, nameTableKind: None)
 !5 = !{}
 !6 = !{!0, !7, !10}
 !7 = !DIGlobalVariableExpression(var: !8, expr: !DIExpression(DW_OP_plus_uconst, 4))
 !8 = distinct !DIGlobalVariable(name: "bb", scope: !2, file: !3, line: 2, type: !9, isLocal: false, isDefinition: true)
 !9 = !DIBasicType(name: "integer", size: 32, align: 32, encoding: DW_ATE_signed)
 !10 = !DIGlobalVariableExpression(var: !11, expr: !DIExpression())
 !11 = distinct !DIGlobalVariable(name: "nml", scope: !2, file: !3, line: 2, type: !12, isLocal: false, isDefinition: true)
 !12 = !DICompositeType(tag: DW_TAG_namelist, name: "nml", file: !3, elements: !13)
 !13 = !{!1, !8}
 !14 = !{!15}
 !15 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !16, entity: !2, file: !3, line: 6)
-!16 = distinct !DISubprogram(name: "test", scope: !4, file: !3, line: 6, type: !17, scopeLine: 6, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition, unit: !4)
+!16 = distinct !DISubprogram(name: "test", scope: !4, file: !3, line: 6, type: !17, scopeLine: 6, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition, unit: !4, retainedNodes: !14)
 !17 = !DISubroutineType(types: !18)
 !18 = !{null}
 !19 = !{i32 2, !"Dwarf Version", i32 4}
 !20 = !{i32 2, !"Debug Info Version", i32 3}
 !21 = distinct !DISubprogram(name: "namelist", scope: !4, file: !3, line: 11, type: !22, scopeLine: 11, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagMainSubprogram, unit: !4)
 !22 = !DISubroutineType(cc: DW_CC_program, types: !18)

llvm/test/DebugInfo/omit-empty.ll

 ; RUN: %llc_dwarf %s -filetype=obj -o - | llvm-objdump -h - | FileCheck %s
 ; REQUIRES: object-emission
 
 ; CHECK-NOT: .debug_
 
 !llvm.dbg.cu = !{!0, !5}
 !llvm.module.flags = !{!3, !4}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2)
 !1 = !DIFile(filename: "<stdin>", directory: "/")
 !2 = !{}
 !3 = !{i32 2, !"Dwarf Version", i32 4}
 !4 = !{i32 2, !"Debug Info Version", i32 3}
-!5 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, imports: !6)
+!5 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
 !6 = !{!7}
 !7 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !8, entity: !8, file: !1, line: 3)
-!8 = distinct !DISubprogram(name: "f2", linkageName: "_Z2f2v", scope: !1, file: !1, line: 2, type: !9, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !5, retainedNodes: !2)
+!8 = distinct !DISubprogram(name: "f2", linkageName: "_Z2f2v", scope: !1, file: !1, line: 2, type: !9, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !5, retainedNodes: !6)
 !9 = !DISubroutineType(types: !10)
 !10 = !{null}
 !11 = !DINamespace(name: "ns", scope: null)

llvm/test/Linker/pr26037.ll

 ; RUN: llvm-as %s -o %t.bc
 ; RUN: llvm-as %p/Inputs/pr26037.ll -o %t2.bc
 ; RUN: llvm-link -S -only-needed %t2.bc %t.bc | FileCheck %s
 
-; CHECK: !DIImportedEntity({{.*}}, scope: ![[B:[0-9]+]], entity: ![[A:[0-9]+]]
-; CHECK: ![[B]] = distinct !DISubprogram(name: "b"
+; CHECK: ![[CU_MAIN:[0-9]+]] = distinct !DICompileUnit(
+; CHECK: ![[CU:[0-9]+]] = distinct !DICompileUnit(
+; CHECK: !DIImportedEntity({{.*}}, scope: ![[CU]], entity: ![[A:[0-9]+]]
 ; CHECK: ![[A]] = distinct !DISubprogram(name: "a"
-; CHECK: !DIImportedEntity({{.*}}, scope: ![[LBC:[0-9]+]], entity: ![[LBD:[0-9]+]]
-; CHECK: ![[LBC]] = distinct !DILexicalBlock(scope: ![[C:[0-9]+]]
-; CHECK: ![[C]] = distinct !DISubprogram(name: "c"
+; CHECK: !DIImportedEntity({{.*}}, scope: ![[CU]], entity: ![[LBD:[0-9]+]]
 ; CHECK: ![[LBD]] = distinct !DILexicalBlock(scope: ![[D:[0-9]+]]
 ; CHECK: ![[D]] = distinct !DISubprogram(name: "d"
 
 define void @_ZN1A1aEv() #0 !dbg !4 {
 entry:
   ret void, !dbg !14
 }
 
-define void @_ZN1A1bEv() #0 !dbg !8 {
-entry:
-  ret void, !dbg !15
-}
-
-define void @_ZN1A1cEv() #0 !dbg !18 {
-entry:
-  ret void, !dbg !21
-}
-
 define void @_ZN1A1dEv() #0 !dbg !20 {
 entry:
   ret void, !dbg !22
 }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!11, !12}
 !llvm.ident = !{!13}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 256934) (llvm/trunk 256936)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, imports: !9)
 !1 = !DIFile(filename: "a2.cc", directory: "")
 !2 = !{}
 !4 = distinct !DISubprogram(name: "a", linkageName: "_ZN1A1aEv", scope: !5, file: !1, line: 7, type: !6, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 !5 = !DINamespace(name: "A", scope: null)
 !6 = !DISubroutineType(types: !7)
 !7 = !{null}
-!8 = distinct !DISubprogram(name: "b", linkageName: "_ZN1A1bEv", scope: !5, file: !1, line: 8, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 !9 = !{!10, !16}
-!10 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !8, entity: !4, file: !1, line: 8)
+!10 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !0, entity: !4, file: !1, line: 8)
 !11 = !{i32 2, !"Dwarf Version", i32 4}
 !12 = !{i32 2, !"Debug Info Version", i32 3}
 !13 = !{!"clang version 3.8.0 (trunk 256934) (llvm/trunk 256936)"}
 !14 = !DILocation(line: 7, column: 12, scope: !4)
-!15 = !DILocation(line: 8, column: 24, scope: !8)
-!16 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !17, entity: !19, file: !1, line: 8)
-!17 = distinct !DILexicalBlock(scope: !18, file: !1, line: 9, column: 8)
-!18 = distinct !DISubprogram(name: "c", linkageName: "_ZN1A1cEv", scope: !5, file: !1, line: 9, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
+!16 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !0, entity: !19, file: !1, line: 8)
 !19 = distinct !DILexicalBlock(scope: !20, file: !1, line: 10, column: 8)
 !20 = distinct !DISubprogram(name: "d", linkageName: "_ZN1A1dEv", scope: !5, file: !1, line: 10, type: !6, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
-!21 = !DILocation(line: 9, column: 8, scope: !18)
 !22 = !DILocation(line: 10, column: 8, scope: !20)

llvm/test/ThinLTO/X86/debuginfo-cu-import.ll

 ; Test to ensure only the necessary DICompileUnit fields are imported
 ; for ThinLTO
 
 ; RUN: opt -module-summary %s -o %t1.bc
 ; RUN: opt -module-summary %p/Inputs/debuginfo-cu-import.ll -o %t2.bc
 ; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc
 
-; Don't import enums, macros, retainedTypes or globals lists.
-; Only import local scope imported entities.
+; Don't import enums, macros, retainedTypes, globals or imports lists.
 ; RUN: llvm-lto -thinlto-action=import %t2.bc -thinlto-index=%t.index.bc -o - | llvm-dis -o - | FileCheck %s
 ; CHECK-NOT: DICompileUnit{{.*}} enums:
 ; CHECK-NOT: DICompileUnit{{.*}} macros:
 ; CHECK-NOT: DICompileUnit{{.*}} retainedTypes:
 ; CHECK-NOT: DICompileUnit{{.*}} globals:
-; CHECK: DICompileUnit{{.*}} imports: ![[IMP:[0-9]+]]
-; CHECK: ![[IMP]] = !{!{{[0-9]+}}}
+; CHECK-NOT: DICompileUnit{{.*}} imports:
 
 ; ModuleID = 'debuginfo-cu-import.c'
 source_filename = "debuginfo-cu-import.c"
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define void @foo() !dbg !28 {
 entry:

 !3 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "enum1", scope: !4, file: !1, line: 50, size: 32, elements: !5, identifier: "_ZTSN9__gnu_cxx12_Lock_policyE")
 !4 = !DINamespace(name: "A", scope: null)
 !5 = !{}
 !6 = !{!7}
 !7 = !DICompositeType(tag: DW_TAG_structure_type, name: "Base", file: !1, line: 1, size: 32, align: 32, elements: !5, identifier: "_ZTS4Base")
 !8 = !{!9}
 !9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression())
 !10 = !DIGlobalVariable(name: "version", scope: !4, file: !1, line: 2, type: !7, isLocal: false, isDefinition: true)
-!11 = !{!12, !16}
+!11 = !{!12}
 !12 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !4, entity: !13, file: !1, line: 8)
 !13 = distinct !DISubprogram(name: "a", linkageName: "_ZN1A1aEv", scope: !4, file: !1, line: 7, type: !14, isLocal: false, isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !5)
 !14 = !DISubroutineType(types: !15)
 !15 = !{null}
 !16 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !17, entity: !19, file: !1, line: 8)
 !17 = distinct !DILexicalBlock(scope: !18, file: !1, line: 9, column: 8)
-!18 = distinct !DISubprogram(name: "c", linkageName: "_ZN1A1cEv", scope: !4, file: !1, line: 9, type: !14, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !5)
+!18 = distinct !DISubprogram(name: "c", linkageName: "_ZN1A1cEv", scope: !4, file: !1, line: 9, type: !14, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !33)
 !19 = distinct !DILexicalBlock(scope: !20, file: !1, line: 10, column: 8)
 !20 = distinct !DISubprogram(name: "d", linkageName: "_ZN1A1dEv", scope: !4, file: !1, line: 10, type: !14, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !5)
 !21 = !{!22}
 !22 = !DIMacroFile(file: !1, nodes: !23)
 !23 = !{!24}
 !24 = !DIMacro(type: DW_MACINFO_define, line: 3, name: "X", value: "5")
 !25 = !{i32 2, !"Dwarf Version", i32 4}
 !26 = !{i32 2, !"Debug Info Version", i32 3}
 !27 = !{!"clang version 4.0.0 (trunk 286863) (llvm/trunk 286875)"}
 !28 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !14, isLocal: false, isDefinition: true, scopeLine: 2, isOptimized: false, unit: !0, retainedNodes: !5)
 !29 = !DILocation(line: 3, column: 1, scope: !28)
 !30 = !DILocation(line: 7, column: 12, scope: !13)
 !31 = distinct !DISubprogram(name: "b", linkageName: "_ZN1A1bEv", scope: !4, file: !1, line: 8, type: !14, isLocal: true, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !5)
 !32 = !DILocation(line: 8, column: 24, scope: !31)
-
+!33 = !{!16}