[clang][DebugInfo] Add symbol for debugger with VTable information. (#130255)

CarlosAlbertoEnciso · web-flow · commit d1b0cbff806b · 2025-05-28T09:15:48.000+01:00
The IR now includes a global variable for the debugger that holds
the address of the vtable.

Now every class that contains virtual functions, has a static
member (marked as artificial) that identifies where that vtable
is loaded in memory. The unmangled name is '_vtable$'.

This new symbol will allow a debugger to easily associate
classes with the physical location of their VTables using
only the DWARF information. Previously, this had to be done
by searching for ELF symbols with matching names; something
that was time-consuming and error-prone in certain edge cases.
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -2635,6 +2635,55 @@ StringRef CGDebugInfo::getVTableName(const CXXRecordDecl *RD) {
   return internString("_vptr$", RD->getNameAsString());
 }
 
+// Emit symbol for the debugger that points to the vtable address for
+// the given class. The symbol is named as '_vtable$'.
+// The debugger does not need to know any details about the contents of the
+// vtable as it can work this out using its knowledge of the ABI and the
+// existing information in the DWARF. The type is assumed to be 'void *'.
+void CGDebugInfo::emitVTableSymbol(llvm::GlobalVariable *VTable,
+                                   const CXXRecordDecl *RD) {
+  if (!CGM.getTarget().getCXXABI().isItaniumFamily())
+    return;
+
+  ASTContext &Context = CGM.getContext();
+  StringRef SymbolName = "_vtable$";
+  SourceLocation Loc;
+  QualType VoidPtr = Context.getPointerType(Context.VoidTy);
+
+  // We deal with two different contexts:
+  // - The type for the variable, which is part of the class that has the
+  //   vtable, is placed in the context of the DICompositeType metadata.
+  // - The DIGlobalVariable for the vtable is put in the DICompileUnitScope.
+
+  // The created non-member should be mark as 'artificial'. It will be
+  // placed inside the scope of the C++ class/structure.
+  llvm::DIScope *DContext = getContextDescriptor(RD, TheCU);
+  auto *Ctxt = cast<llvm::DICompositeType>(DContext);
+  llvm::DIFile *Unit = getOrCreateFile(Loc);
+  llvm::DIType *VTy = getOrCreateType(VoidPtr, Unit);
+  llvm::DINode::DIFlags Flags = getAccessFlag(AccessSpecifier::AS_private, RD) |
+                                llvm::DINode::FlagArtificial;
+  auto Tag = CGM.getCodeGenOpts().DwarfVersion >= 5
+                 ? llvm::dwarf::DW_TAG_variable
+                 : llvm::dwarf::DW_TAG_member;
+  llvm::DIDerivedType *DT = DBuilder.createStaticMemberType(
+      Ctxt, SymbolName, Unit, /*LineNumber=*/0, VTy, Flags,
+      /*Val=*/nullptr, Tag);
+
+  // Use the same vtable pointer to global alignment for the symbol.
+  unsigned PAlign = CGM.getVtableGlobalVarAlignment();
+
+  // The global variable is in the CU scope, and links back to the type it's
+  // "within" via the declaration field.
+  llvm::DIGlobalVariableExpression *GVE =
+      DBuilder.createGlobalVariableExpression(
+          TheCU, SymbolName, VTable->getName(), Unit, /*LineNo=*/0,
+          getOrCreateType(VoidPtr, Unit), VTable->hasLocalLinkage(),
+          /*isDefined=*/true, nullptr, DT, /*TemplateParameters=*/nullptr,
+          PAlign);
+  VTable->addDebugInfo(GVE);
+}
+
 StringRef CGDebugInfo::getDynamicInitializerName(const VarDecl *VD,
                                                  DynamicInitKind StubKind,
                                                  llvm::Function *InitFn) {
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
@@ -669,6 +669,9 @@ class CGDebugInfo {
   void addInstToSpecificSourceAtom(llvm::Instruction *KeyInstruction,
                                    llvm::Value *Backup, uint64_t Atom);
 
+  /// Emit symbol for debugger that holds the pointer to the vtable.
+  void emitVTableSymbol(llvm::GlobalVariable *VTable, const CXXRecordDecl *RD);
+
 private:
   /// Amend \p I's DebugLoc with \p Group (its source atom group) and \p
   /// Rank (lower nonzero rank is higher precedence). Does nothing if \p I
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
@@ -1810,6 +1810,15 @@ class CodeGenModule : public CodeGenTypeCache {
     return !getLangOpts().CPlusPlus;
   }
 
+  // Helper to get the alignment for a variable.
+  unsigned getVtableGlobalVarAlignment(const VarDecl *D = nullptr) {
+    LangAS AS = GetGlobalVarAddressSpace(D);
+    unsigned PAlign = getItaniumVTableContext().isRelativeLayout()
+                          ? 32
+                          : getTarget().getPointerAlign(AS);
+    return PAlign;
+  }
+
 private:
   bool shouldDropDLLAttribute(const Decl *D, const llvm::GlobalValue *GV) const;
 
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2061,6 +2061,10 @@ void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
     if (!VTable->isDSOLocal())
       CGVT.GenerateRelativeVTableAlias(VTable, VTable->getName());
   }
+
+  // Emit symbol for debugger only if requested debug info.
+  if (CGDebugInfo *DI = CGM.getModuleDebugInfo())
+    DI->emitVTableSymbol(VTable, RD);
 }
 
 bool ItaniumCXXABI::isVirtualOffsetNeededForVTableField(
@@ -2166,10 +2170,7 @@ llvm::GlobalVariable *ItaniumCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
   // Use pointer to global alignment for the vtable. Otherwise we would align
   // them based on the size of the initializer which doesn't make sense as only
   // single values are read.
-  LangAS AS = CGM.GetGlobalVarAddressSpace(nullptr);
-  unsigned PAlign = CGM.getItaniumVTableContext().isRelativeLayout()
-                        ? 32
-                        : CGM.getTarget().getPointerAlign(AS);
+  unsigned PAlign = CGM.getVtableGlobalVarAlignment();
 
   VTable = CGM.CreateOrReplaceCXXRuntimeVariable(
       Name, VTableType, llvm::GlobalValue::ExternalLinkage,
diff --git a/clang/test/CodeGenCXX/debug-info-class.cpp b/clang/test/CodeGenCXX/debug-info-class.cpp
@@ -122,14 +122,6 @@ int main(int argc, char **argv) {
 // CHECK-SAME:             ){{$}}
 
 // CHECK:      ![[INT:[0-9]+]] = !DIBasicType(name: "int"
-// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
-// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "bar"
-// CHECK: !DICompositeType(tag: DW_TAG_union_type, name: "baz"
-// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "B"
-// CHECK-NOT:              DIFlagFwdDecl
-// CHECK-SAME:             ){{$}}
-// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "_vptr$B",
-// CHECK-SAME:           DIFlagArtificial
 
 // CHECK: [[C:![0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "C",
 // CHECK-NOT:                              DIFlagFwdDecl
@@ -145,6 +137,20 @@ int main(int argc, char **argv) {
 // CHECK-SAME:                     DIFlagStaticMember
 // CHECK: [[C_DTOR]] = !DISubprogram(name: "~C"
 
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "K"
+// CHECK-SAME:             identifier: "_ZTS1K"
+// CHECK-SAME:             ){{$}}
+
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "B"
+// CHECK-NOT:              DIFlagFwdDecl
+// CHECK-SAME:             ){{$}}
+// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "_vptr$B",
+// CHECK-SAME:           DIFlagArtificial
+
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
+// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "bar"
+// CHECK: !DICompositeType(tag: DW_TAG_union_type, name: "baz"
+
 // CHECK: [[D:![0-9]+]] = !DICompositeType(tag: DW_TAG_structure_type, name: "D"
 // CHECK-SAME:             size:
 // CHECK-SAME:             DIFlagFwdDecl
@@ -156,10 +162,6 @@ int main(int argc, char **argv) {
 // CHECK-NOT:              identifier:
 // CHECK-SAME:             ){{$}}
 
-// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "K"
-// CHECK-SAME:             identifier: "_ZTS1K"
-// CHECK-SAME:             ){{$}}
-
 // CHECK: [[L:![0-9]+]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "L"
 // CHECK-SAME:             ){{$}}
 // CHECK: [[L_FUNC_DECL:![0-9]*]] = !DISubprogram(name: "func",{{.*}} scope: [[L]]
diff --git a/clang/test/CodeGenCXX/debug-info-template-member.cpp b/clang/test/CodeGenCXX/debug-info-template-member.cpp
@@ -22,29 +22,6 @@ inline int add3(int x) {
 // CHECK: [[X]] = !DIGlobalVariableExpression(var: [[XV:.*]], expr: !DIExpression())
 // CHECK: [[XV]] = distinct !DIGlobalVariable(name: "x",
 // CHECK-SAME:                                type: ![[OUTER_FOO_INNER_ID:[0-9]+]]
-//
-// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
-// CHECK-SAME: name: "var"
-// CHECK-SAME: templateParams: {{![0-9]+}}
-// CHECK: !DITemplateTypeParameter(name: "T", type: [[TY:![0-9]+]])
-// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
-// CHECK-SAME: name: "var"
-// CHECK-SAME: templateParams: {{![0-9]+}}
-// CHECK: !DITemplateTypeParameter(name: "T", type: {{![0-9]+}})
-// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
-// CHECK-SAME: name: "varray"
-// CHECK-SAME: templateParams: {{![0-9]+}}
-// CHECK: !DITemplateValueParameter(name: "N", type: [[TY]], value: i32 1)
-
-// CHECK: ![[OUTER_FOO_INNER_ID:[0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "inner"{{.*}}, identifier:
-// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
-// CHECK-SAME:             elements: [[FOO_MEM:![0-9]*]]
-// CHECK-SAME:             identifier: "_ZTS3foo"
-// CHECK: [[FOO_MEM]] = !{[[FOO_FUNC:![0-9]*]]}
-// CHECK: [[FOO_FUNC]] = !DISubprogram(name: "func", linkageName: "_ZN3foo4funcEN5outerIS_E5innerE",
-// CHECK-SAME:                         type: [[FOO_FUNC_TYPE:![0-9]*]]
-// CHECK: [[FOO_FUNC_TYPE]] = !DISubroutineType(types: [[FOO_FUNC_PARAMS:![0-9]*]])
-// CHECK: [[FOO_FUNC_PARAMS]] = !{null, !{{[0-9]*}}, ![[OUTER_FOO_INNER_ID]]}
 
 // CHECK: [[C:![0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "MyClass"
 // CHECK-SAME:                             elements: [[C_MEM:![0-9]*]]
@@ -55,9 +32,6 @@ inline int add3(int x) {
 
 // CHECK: [[C_FUNC]] = !DISubprogram(name: "func",{{.*}} line: 9,
 
-// CHECK: !DISubprogram(name: "add<2>"
-// CHECK-SAME:          scope: [[C]]
-//
 // CHECK: [[VIRT_TEMP:![0-9]+]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "virt<elem>"
 // CHECK-SAME:             elements: [[VIRT_MEM:![0-9]*]]
 // CHECK-SAME:             vtableHolder: [[VIRT_TEMP]]
@@ -74,6 +48,32 @@ inline int add3(int x) {
 // CHECK: [[VIRT_TEMP_PARAM]] = !{[[VIRT_T:![0-9]*]]}
 // CHECK: [[VIRT_T]] = !DITemplateTypeParameter(name: "T", type: [[ELEM]])
 
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "var"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateTypeParameter(name: "T", type: [[TY:![0-9]+]])
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "var"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateTypeParameter(name: "T", type: {{![0-9]+}})
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "varray"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateValueParameter(name: "N", type: [[TY]], value: i32 1)
+
+// CHECK: ![[OUTER_FOO_INNER_ID:[0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "inner"{{.*}}, identifier:
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
+// CHECK-SAME:             elements: [[FOO_MEM:![0-9]*]]
+// CHECK-SAME:             identifier: "_ZTS3foo"
+// CHECK: [[FOO_MEM]] = !{[[FOO_FUNC:![0-9]*]]}
+// CHECK: [[FOO_FUNC]] = !DISubprogram(name: "func", linkageName: "_ZN3foo4funcEN5outerIS_E5innerE",
+// CHECK-SAME:                         type: [[FOO_FUNC_TYPE:![0-9]*]]
+// CHECK: [[FOO_FUNC_TYPE]] = !DISubroutineType(types: [[FOO_FUNC_PARAMS:![0-9]*]])
+// CHECK: [[FOO_FUNC_PARAMS]] = !{null, !{{[0-9]*}}, ![[OUTER_FOO_INNER_ID]]}
+
+// CHECK: !DISubprogram(name: "add<2>"
+// CHECK-SAME:          scope: [[C]]
+
 template<typename T>
 struct outer {
   struct inner {
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-diamond.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-diamond.cpp
@@ -0,0 +1,87 @@
+// REQUIRES: target={{x86_64.*-linux.*}}
+
+// Diamond inheritance case:
+// For CBase, CLeft, CRight and CDerived we check:
+// - Generation of their vtables (including attributes).
+// - Generation of their '_vtable$' data members:
+//   * Correct scope and attributes
+
+namespace NSP {
+  struct CBase {
+    int B = 0;
+    virtual char fooBase() { return 'B'; }
+  };
+}
+
+namespace NSP_1 {
+  struct CLeft : NSP::CBase {
+    int M1 = 1;
+    char fooBase() override { return 'O'; };
+    virtual int fooLeft() { return 1; }
+  };
+}
+
+namespace NSP_2 {
+  struct CRight : NSP::CBase {
+    int M2 = 2;
+    char fooBase() override { return 'T'; };
+    virtual int fooRight() { return 2; }
+  };
+}
+
+struct CDerived : NSP_1::CLeft, NSP_2::CRight {
+  int D = 3;
+  char fooBase() override { return 'D'; };
+  int fooDerived() { return 3; };
+};
+
+int main() {
+  NSP::CBase Base;
+  NSP_1::CLeft Left;
+  NSP_2::CRight Right;
+  CDerived Derived;
+
+  return 0;
+}
+
+// RUN: %clang --target=x86_64-linux -Xclang -disable-O0-optnone -Xclang -disable-llvm-passes -emit-llvm -S -g %s -o - | FileCheck %s
+
+// CHECK: $_ZTVN3NSP5CBaseE = comdat any
+// CHECK: $_ZTVN5NSP_15CLeftE = comdat any
+// CHECK: $_ZTVN5NSP_26CRightE = comdat any
+// CHECK: $_ZTV8CDerived = comdat any
+
+// CHECK: @_ZTVN3NSP5CBaseE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[BASE_VTABLE_VAR:![0-9]*]]
+// CHECK: @_ZTVN5NSP_15CLeftE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[LEFT_VTABLE_VAR:![0-9]*]]
+// CHECK: @_ZTVN5NSP_26CRightE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[RIGHT_VTABLE_VAR:![0-9]*]]
+// CHECK: @_ZTV8CDerived = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[DERIVED_VTABLE_VAR:![0-9]*]]
+
+// CHECK: [[BASE_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[BASE_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[BASE_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN3NSP5CBaseE"
+
+// CHECK: [[LEFT_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[LEFT_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[LEFT_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN5NSP_15CLeftE"
+
+// CHECK: [[TYPE:![0-9]*]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[LEFT:![0-9]*]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
+
+// CHECK: [[LEFT]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CLeft"
+
+// CHECK: [[BASE:![0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CBase"
+
+// CHECK: [[RIGHT_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[RIGHT_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[RIGHT_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN5NSP_26CRightE"
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[RIGHT:![0-9]*]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
+
+// CHECK: [[RIGHT]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CRight"
+
+// CHECK: [[DERIVED_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[DERIVED_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[DERIVED_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTV8CDerived"
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[DERIVED:![0-9]*]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
+
+// CHECK: [[DERIVED]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CDerived"
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[BASE]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-multiple.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-multiple.cpp
@@ -0,0 +1,72 @@
+// REQUIRES: target={{x86_64.*-linux.*}}
+
+// Multiple inheritance case:
+// For CBaseOne, CBaseTwo and CDerived we check:
+// - Generation of their vtables (including attributes).
+// - Generation of their '_vtable$' data members:
+//   * Correct scope and attributes
+
+namespace NSP_1 {
+  struct CBaseOne {
+    int B1 = 1;
+    virtual int one() { return 1; }
+    virtual int two() { return 2; }
+    virtual int three() { return 3; }
+  };
+}
+
+namespace NSP_2 {
+  struct CBaseTwo {
+    int B2 = 1;
+    virtual int four() { return 4; }
+    virtual int five() { return 5; }
+    virtual int six() { return 6; }
+  };
+}
+
+struct CDerived : NSP_1::CBaseOne, NSP_2::CBaseTwo {
+  int D = 1;
+  int two() override { return 22; };
+  int six() override { return 66; }
+};
+
+int main() {
+  NSP_1::CBaseOne BaseOne;
+  NSP_2::CBaseTwo BaseTwo;
+  CDerived Derived;
+
+  return 0;
+}
+
+// RUN: %clang --target=x86_64-linux -Xclang -disable-O0-optnone -Xclang -disable-llvm-passes -emit-llvm -S -g %s -o - | FileCheck %s
+
+// CHECK: $_ZTVN5NSP_18CBaseOneE = comdat any
+// CHECK: $_ZTVN5NSP_28CBaseTwoE = comdat any
+// CHECK: $_ZTV8CDerived = comdat any
+
+// CHECK: @_ZTVN5NSP_18CBaseOneE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[BASE_ONE_VTABLE_VAR:![0-9]*]]
+// CHECK: @_ZTVN5NSP_28CBaseTwoE = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[BASE_TWO_VTABLE_VAR:![0-9]*]]
+// CHECK: @_ZTV8CDerived = linkonce_odr {{dso_local|hidden}} unnamed_addr constant {{.*}}, comdat, align 8, !dbg [[DERIVED_VTABLE_VAR:![0-9]*]]
+
+// CHECK: [[BASE_ONE_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[BASE_ONE_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[BASE_ONE_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN5NSP_18CBaseOneE"
+
+// CHECK: [[BASE_TWO_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[BASE_TWO_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK-NEXT: [[BASE_TWO_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTVN5NSP_28CBaseTwoE"
+
+// CHECK: [[TYPE:![0-9]*]] = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[BASE_TWO:![0-9]*]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
+
+// check: [[BASE_TWO]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CBaseTwo"
+
+// CHECK: [[DERIVED_VTABLE_VAR]] = !DIGlobalVariableExpression(var: [[DERIVED_VTABLE:![0-9]*]], expr: !DIExpression())
+// CHECK: [[DERIVED_VTABLE]] = distinct !DIGlobalVariable(name: "_vtable$", linkageName: "_ZTV8CDerived"
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[DERIVED:![0-9]*]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
+
+// CHECK: [[DERIVED]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CDerived"
+
+// CHECK: [[BASE_ONE:![0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "CBaseOne"
+
+// CHECK: !DIDerivedType(tag: DW_TAG_variable, name: "_vtable$", scope: [[BASE_ONE]], file: {{.*}}, baseType: [[TYPE]], flags: DIFlagPrivate | DIFlagArtificial | DIFlagStaticMember)
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple-main.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple-main.cpp
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-simple.cpp
diff --git a/clang/test/CodeGenCXX/vtable-debug-info-inheritance-virtual.cpp b/clang/test/CodeGenCXX/vtable-debug-info-inheritance-virtual.cpp
diff --git a/clang/test/Modules/ExtDebugInfo.cpp b/clang/test/Modules/ExtDebugInfo.cpp
