Index: docs/SourceLevelDebugging.rst
===================================================================
--- docs/SourceLevelDebugging.rst
+++ docs/SourceLevelDebugging.rst
@@ -406,23 +406,20 @@
   !llvm.ident = !{!8}
 
   ;; Define the global variable itself
-  !0 = distinct !DIGlobalVariable(name: "MyGlobal", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, align: 64)
+  !0 = !DIGlobalVariableExpression(var: !1)
+  !1 = distinct !DIGlobalVariable(name: "MyGlobal", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, align: 64, unit: !2)
 
   ;; Define the compile unit.
-  !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2,
+  !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3,
                                producer: "clang version 4.0.0 (http://llvm.org/git/clang.git ae4deadbea242e8ea517eef662c30443f75bd086) (http://llvm.org/git/llvm.git 818b4c1539df3e51dc7e62c89ead4abfd348827d)",
-                               isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug,
-                               enums: !3, globals: !4)
+                               isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
 
   ;;
   ;; Define the file
   ;;
-  !2 = !DIFile(filename: "/dev/stdin",
+  !3 = !DIFile(filename: "/dev/stdin",
                directory: "/Users/dexonsmith/data/llvm/debug-info")
 
-  ;; An empty array.
-  !3 = !{}
-
   ;; The Array of Global Variables
   !4 = !{!0}
 
@@ -447,6 +444,22 @@
 alignment is considered default. This is used when producing DWARF output
 for DW_AT_alignment value.
 
+Global variables occur in three forms in the debug info metadata:
+1. *Variable definitions* are reachable via a !dbg attachment on a global that
+   points to a DIGlobalVariableExpression which typically points to a distinct
+   DIGlobalVariable (and an optional DIExpression) with a unit field pointing to
+   the variable's DICompileUnit.  If the compile unit the global variable gets
+   emitted into doesn't matter (e.g., for linkonce_odr symbols), the
+   DIGlobalVariable may instead be unique (i.e., not distinct) and not have a
+   unit field.
+
+2. *Constant definitions* are reachable via the DICompileUnit's list of globals
+   which points to a DIGlobalVariableExpression with a DIGlobalVariable without
+   a unit field and a DIExpression describing a constant value.
+
+3. *Declarations* are DIGlobalVariables without a unit field that are only
+   reachable via a DIImportedEntity and have isDefinition set to false.
+
 C/C++ function information
 --------------------------
 
Index: include/llvm/IR/DIBuilder.h
===================================================================
--- include/llvm/IR/DIBuilder.h
+++ include/llvm/IR/DIBuilder.h
@@ -495,13 +495,16 @@
     /// \param Expr        The location of the global relative to the attached
     ///                    GlobalVariable.
     /// \param Decl        Reference to the corresponding declaration.
-    /// \param AlignInBits Variable alignment(or 0 if no alignment attr was
-    ///                    specified)
+    /// \param AlignInBits Variable alignment (or 0 if no alignment attr was
+    ///                    specified).
+    /// \param Shared      This will create a unique node that is not
+    ///                    associated with a specific \a DICompileUnit and is
+    ///                    intended to be used with linkonce_odr globals.
     DIGlobalVariableExpression *createGlobalVariableExpression(
         DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *File,
         unsigned LineNo, DIType *Ty, bool isLocalToUnit,
         DIExpression *Expr = nullptr, MDNode *Decl = nullptr,
-        uint32_t AlignInBits = 0);
+        uint32_t AlignInBits = 0, bool Shared = false);
 
     /// Identical to createGlobalVariable
     /// except that the resulting DbgNode is temporary and meant to be RAUWed.
Index: include/llvm/IR/DebugInfoMetadata.h
===================================================================
--- include/llvm/IR/DebugInfoMetadata.h
+++ include/llvm/IR/DebugInfoMetadata.h
@@ -2281,49 +2281,50 @@
         IsLocalToUnit(IsLocalToUnit), IsDefinition(IsDefinition) {}
   ~DIGlobalVariable() = default;
 
-  static DIGlobalVariable *getImpl(LLVMContext &Context, DIScope *Scope,
-                                   StringRef Name, StringRef LinkageName,
-                                   DIFile *File, unsigned Line, DITypeRef Type,
-                                   bool IsLocalToUnit, bool IsDefinition,
-                                   DIDerivedType *StaticDataMemberDeclaration,
-                                   uint32_t AlignInBits, StorageType Storage,
-                                   bool ShouldCreate = true) {
+  static DIGlobalVariable *
+  getImpl(LLVMContext &Context, DIScope *Scope, StringRef Name,
+          StringRef LinkageName, DIFile *File, unsigned Line, DITypeRef Type,
+          bool IsLocalToUnit, bool IsDefinition,
+          DIDerivedType *StaticDataMemberDeclaration, uint32_t AlignInBits,
+          DICompileUnit *Unit, StorageType Storage, bool ShouldCreate = true) {
     return getImpl(Context, Scope, getCanonicalMDString(Context, Name),
                    getCanonicalMDString(Context, LinkageName), File, Line, Type,
                    IsLocalToUnit, IsDefinition, StaticDataMemberDeclaration,
-                   AlignInBits, Storage, ShouldCreate);
+                   AlignInBits, Unit, Storage, ShouldCreate);
   }
   static DIGlobalVariable *
   getImpl(LLVMContext &Context, Metadata *Scope, MDString *Name,
           MDString *LinkageName, Metadata *File, unsigned Line, Metadata *Type,
           bool IsLocalToUnit, bool IsDefinition,
           Metadata *StaticDataMemberDeclaration, uint32_t AlignInBits,
-          StorageType Storage, bool ShouldCreate = true);
+          Metadata *Unit, StorageType Storage, bool ShouldCreate = true);
 
   TempDIGlobalVariable cloneImpl() const {
     return getTemporary(getContext(), getScope(), getName(), getLinkageName(),
                         getFile(), getLine(), getType(), isLocalToUnit(),
                         isDefinition(), getStaticDataMemberDeclaration(),
-                        getAlignInBits());
+                        getAlignInBits(), getUnit());
   }
 
 public:
   DEFINE_MDNODE_GET(DIGlobalVariable,
-                    (DIScope * Scope, StringRef Name, StringRef LinkageName,
+                    (DIScope *Scope, StringRef Name, StringRef LinkageName,
                      DIFile *File, unsigned Line, DITypeRef Type,
                      bool IsLocalToUnit, bool IsDefinition,
                      DIDerivedType *StaticDataMemberDeclaration,
-                     uint32_t AlignInBits),
+                     uint32_t AlignInBits, DICompileUnit *Unit),
                     (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
-                     IsDefinition, StaticDataMemberDeclaration, AlignInBits))
+                     IsDefinition, StaticDataMemberDeclaration, AlignInBits,
+                     Unit))
   DEFINE_MDNODE_GET(DIGlobalVariable,
-                    (Metadata * Scope, MDString *Name, MDString *LinkageName,
+                    (Metadata *Scope, MDString *Name, MDString *LinkageName,
                      Metadata *File, unsigned Line, Metadata *Type,
                      bool IsLocalToUnit, bool IsDefinition,
                      Metadata *StaticDataMemberDeclaration,
-                     uint32_t AlignInBits),
+                     uint32_t AlignInBits, Metadata *Unit),
                     (Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
-                     IsDefinition, StaticDataMemberDeclaration, AlignInBits))
+                     IsDefinition, StaticDataMemberDeclaration, AlignInBits,
+                     Unit))
 
   TempDIGlobalVariable clone() const { return cloneImpl(); }
 
@@ -2334,9 +2335,13 @@
   DIDerivedType *getStaticDataMemberDeclaration() const {
     return cast_or_null<DIDerivedType>(getRawStaticDataMemberDeclaration());
   }
+  DICompileUnit *getUnit() const {
+    return cast_or_null<DICompileUnit>(getRawUnit());
+  }
 
   MDString *getRawLinkageName() const { return getOperandAs<MDString>(5); }
   Metadata *getRawStaticDataMemberDeclaration() const { return getOperand(6); }
+  Metadata *getRawUnit() const { return getOperand(7); }
 
   static bool classof(const Metadata *MD) {
     return MD->getMetadataID() == DIGlobalVariableKind;
Index: lib/AsmParser/LLParser.cpp
===================================================================
--- lib/AsmParser/LLParser.cpp
+++ lib/AsmParser/LLParser.cpp
@@ -4241,14 +4241,16 @@
   OPTIONAL(isLocal, MDBoolField, );                                            \
   OPTIONAL(isDefinition, MDBoolField, (true));                                 \
   OPTIONAL(declaration, MDField, );                                            \
-  OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));
+  OPTIONAL(align, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(unit, MDField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
 
-  Result = GET_OR_DISTINCT(DIGlobalVariable,
-                           (Context, scope.Val, name.Val, linkageName.Val,
-                            file.Val, line.Val, type.Val, isLocal.Val,
-                            isDefinition.Val, declaration.Val, align.Val));
+  Result =
+      GET_OR_DISTINCT(DIGlobalVariable,
+                      (Context, scope.Val, name.Val, linkageName.Val, file.Val,
+                       line.Val, type.Val, isLocal.Val, isDefinition.Val,
+                       declaration.Val, align.Val, unit.Val));
   return false;
 }
 
Index: lib/Bitcode/Reader/MetadataLoader.cpp
===================================================================
--- lib/Bitcode/Reader/MetadataLoader.cpp
+++ lib/Bitcode/Reader/MetadataLoader.cpp
@@ -452,6 +452,8 @@
   bool StripTBAA = false;
   bool HasSeenOldLoopTags = false;
   bool NeedUpgradeToDIGlobalVariableExpression = false;
+  /// Are there DIGLobalVariables without a unit field that must be upgraded?
+  bool DIGlobalVariablesWithoutUnits = false;
 
   /// True if metadata is being parsed for a module being ThinLTO imported.
   bool IsImporting = false;
@@ -511,9 +513,26 @@
     }
   }
 
+  /// Upgrade global variables without units.
+  void upgradeVariablesWithoutUnits() {
+    if (!DIGlobalVariablesWithoutUnits)
+      return;
+    if (auto *CUs = TheModule.getNamedMetadata("llvm.dbg.cu"))
+      for (auto *N : CUs->operands())
+        if (auto *CU = dyn_cast_or_null<DICompileUnit>(N))
+          if (auto *GVEs =
+                  dyn_cast_or_null<MDTuple>(CU->getRawGlobalVariables()))
+            for (auto &N1 : GVEs->operands())
+              if (auto *GVE = dyn_cast_or_null<DIGlobalVariableExpression>(N1))
+                if (auto *GV = GVE->getVariable())
+                  if (GV->isDefinition())
+                    GV->replaceOperandWith(7, CU);
+  }
+
   void upgradeDebugInfo() {
     upgradeCUSubprograms();
     upgradeCUVariables();
+    upgradeVariablesWithoutUnits();
   }
 
 public:
@@ -1431,19 +1450,31 @@
     IsDistinct = Record[0] & 1;
     unsigned Version = Record[0] >> 1;
 
-    if (Version == 1) {
+    if (Version == 2) {
+      MetadataList.assignValue(
+          GET_OR_DISTINCT(
+              DIGlobalVariable,
+              (Context, getMDOrNull(Record[1]), getMDString(Record[2]),
+               getMDString(Record[3]), getMDOrNull(Record[4]), Record[5],
+               getDITypeRefOrNull(Record[6]), Record[7], Record[8],
+               getMDOrNull(Record[9]), Record[10], getMDOrNull(Record[11]))),
+          NextMetadataNo);
+      NextMetadataNo++;
+    } else if (Version == 1) {
+      DIGlobalVariablesWithoutUnits = true;
       MetadataList.assignValue(
           GET_OR_DISTINCT(DIGlobalVariable,
                           (Context, getMDOrNull(Record[1]),
                            getMDString(Record[2]), getMDString(Record[3]),
                            getMDOrNull(Record[4]), Record[5],
                            getDITypeRefOrNull(Record[6]), Record[7], Record[8],
-                           getMDOrNull(Record[10]), Record[11])),
+                           nullptr, Record[10], getMDOrNull(Record[11]))),
           NextMetadataNo);
       NextMetadataNo++;
     } else if (Version == 0) {
       // Upgrade old metadata, which stored a global variable reference or a
       // ConstantInt here.
+      DIGlobalVariablesWithoutUnits = true;
       NeedUpgradeToDIGlobalVariableExpression = true;
       Metadata *Expr = getMDOrNull(Record[9]);
       uint32_t AlignInBits = 0;
@@ -1470,7 +1501,7 @@
           (Context, getMDOrNull(Record[1]), getMDString(Record[2]),
            getMDString(Record[3]), getMDOrNull(Record[4]), Record[5],
            getDITypeRefOrNull(Record[6]), Record[7], Record[8],
-           getMDOrNull(Record[10]), AlignInBits));
+          getMDOrNull(Record[10]), AlignInBits, nullptr));
 
       DIGlobalVariableExpression *DGVE = nullptr;
       if (Attach || Expr)
Index: lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- lib/Bitcode/Writer/BitcodeWriter.cpp
+++ lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1693,8 +1693,8 @@
 void ModuleBitcodeWriter::writeDIGlobalVariable(
     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
     unsigned Abbrev) {
-  const uint64_t Version = 1 << 1;
-  Record.push_back((uint64_t)N->isDistinct() | Version);
+  const uint64_t Version = 2;
+  Record.push_back((uint64_t)N->isDistinct() | (Version << 1));
   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
@@ -1703,9 +1703,9 @@
   Record.push_back(VE.getMetadataOrNullID(N->getType()));
   Record.push_back(N->isLocalToUnit());
   Record.push_back(N->isDefinition());
-  Record.push_back(/* expr */ 0);
   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
   Record.push_back(N->getAlignInBits());
+  Record.push_back(VE.getMetadataOrNullID(N->getUnit()));
 
   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
   Record.clear();
Index: lib/CodeGen/AsmPrinter/DwarfDebug.cpp
===================================================================
--- lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -486,12 +486,6 @@
 	      }
               return false;
             });
-  GVEs.erase(std::unique(GVEs.begin(), GVEs.end(),
-                         [](DwarfCompileUnit::GlobalExpr A,
-                            DwarfCompileUnit::GlobalExpr B) {
-                           return A.Expr == B.Expr;
-                         }),
-             GVEs.end());
   return GVEs;
 }
 
@@ -511,13 +505,37 @@
   // Tell MMI whether we have debug info.
   MMI->setDebugInfoAvailability(NumDebugCUs > 0);
   SingleCU = NumDebugCUs == 1;
-  DenseMap<DIGlobalVariable *, SmallVector<DwarfCompileUnit::GlobalExpr, 1>>
-      GVMap;
+  // Collect DIGlobalVariables reachable via global variable !dbg attachments.
+  // For each CU we keep a worklist to preserve the globals' relative order.
+  using GlobalExpr = DwarfCompileUnit::GlobalExpr;
+  using ExprListType = SmallVector<GlobalExpr, 1>;
+  using GVMapType = DenseMap<DIGlobalVariable *, std::unique_ptr<ExprListType>>;
+  using WorklistType =
+      std::vector<std::pair<DIGlobalVariable *, ExprListType *>>;
+  DenseMap<DICompileUnit *, std::pair<GVMapType, WorklistType>> UnitGVs;
+
+  // Insert Var into GVMap and add a worklist entry if none exists.
+  auto insertIntoWorklist = [](GVMapType &GVMap, WorklistType &Worklist,
+                               DIGlobalVariable *Var) -> ExprListType & {
+    auto EntrySuccess = GVMap.insert({Var, llvm::make_unique<ExprListType>()});
+    auto Entry = EntrySuccess.first;
+    ExprListType &Exprs = *Entry->second;
+    if (EntrySuccess.second)
+      Worklist.push_back({Var, &Exprs});
+    return Exprs;
+  };
+
   for (const GlobalVariable &Global : M->globals()) {
     SmallVector<DIGlobalVariableExpression *, 1> GVs;
     Global.getDebugInfo(GVs);
-    for (auto *GVE : GVs)
-      GVMap[GVE->getVariable()].push_back({&Global, GVE->getExpression()});
+    for (auto *GVE : GVs) {
+      auto *Var = GVE->getVariable();
+      auto &GVMapWorklist = UnitGVs[Var->getUnit()];
+      GVMapType &GVMap = GVMapWorklist.first;
+      WorklistType &Worklist = GVMapWorklist.second;
+      ExprListType &Exprs = insertIntoWorklist(GVMap, Worklist, Var);
+      Exprs.push_back({&Global, GVE->getExpression()});
+    }
   }
 
   for (DICompileUnit *CUNode : M->debug_compile_units()) {
@@ -525,14 +543,24 @@
     for (auto *IE : CUNode->getImportedEntities())
       CU.addImportedEntity(IE);
 
-    // Global Variables.
-    for (auto *GVE : CUNode->getGlobalVariables())
-      GVMap[GVE->getVariable()].push_back({nullptr, GVE->getExpression()});
-    DenseSet<DIGlobalVariable *> Processed;
-    for (auto *GVE : CUNode->getGlobalVariables()) {
-      DIGlobalVariable *GV = GVE->getVariable();
-      if (Processed.insert(GV).second)
-        CU.getOrCreateGlobalVariableDIE(GV, sortGlobalExprs(GVMap[GV]));
+    // Collect DIGlobalVariables reachable via the DICompileUnit.
+    auto &GVMapWorklist = UnitGVs[CUNode];
+    GVMapType &GVMap = GVMapWorklist.first;
+    WorklistType &Worklist = GVMapWorklist.second;
+     for (auto *GVE : CUNode->getGlobalVariables()) {
+      auto *Var = GVE->getVariable();
+      auto *Expr = GVE->getExpression();
+      ExprListType &Exprs = insertIntoWorklist(GVMap, Worklist, Var);
+      if (std::none_of(Exprs.begin(), Exprs.end(),
+                       [&Expr](GlobalExpr &GE) { return GE.Expr == Expr; }))
+        Exprs.push_back({nullptr, Expr});
+    }
+
+    // Emit all DIGlobalVariables belonging to the current CU.
+    for (auto &GVEntry : Worklist) {
+      DIGlobalVariable *GV = GVEntry.first;
+      ExprListType &Exprs = *GVEntry.second;
+      CU.getOrCreateGlobalVariableDIE(GV, sortGlobalExprs(Exprs));
     }
 
     for (auto *Ty : CUNode->getEnumTypes()) {
Index: lib/IR/AsmWriter.cpp
===================================================================
--- lib/IR/AsmWriter.cpp
+++ lib/IR/AsmWriter.cpp
@@ -1844,6 +1844,7 @@
   Printer.printBool("isDefinition", N->isDefinition());
   Printer.printMetadata("declaration", N->getRawStaticDataMemberDeclaration());
   Printer.printInt("align", N->getAlignInBits());
+  Printer.printMetadata("unit", N->getUnit());
   Out << ")";
 }
 
Index: lib/IR/DIBuilder.cpp
===================================================================
--- lib/IR/DIBuilder.cpp
+++ lib/IR/DIBuilder.cpp
@@ -576,16 +576,24 @@
 #endif
 }
 
+template <class... Ts>
+static DIGlobalVariable *getGlobalVariable(bool IsDistinct, Ts &&... Args) {
+  if (IsDistinct)
+    return DIGlobalVariable::getDistinct(std::forward<Ts>(Args)...);
+  return DIGlobalVariable::get(std::forward<Ts>(Args)...);
+}
+
 DIGlobalVariableExpression *DIBuilder::createGlobalVariableExpression(
     DIScope *Context, StringRef Name, StringRef LinkageName, DIFile *F,
     unsigned LineNumber, DIType *Ty, bool isLocalToUnit, DIExpression *Expr,
-    MDNode *Decl, uint32_t AlignInBits) {
+    MDNode *Decl, uint32_t AlignInBits, bool Shared) {
   checkGlobalVariableScope(Context);
 
-  auto *GV = DIGlobalVariable::getDistinct(
-      VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
+  bool Distinct = !Shared;
+  auto *GV = getGlobalVariable(
+      Distinct, VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
       LineNumber, Ty, isLocalToUnit, true, cast_or_null<DIDerivedType>(Decl),
-      AlignInBits);
+      AlignInBits, Distinct ? CUNode : nullptr);
   auto *N = DIGlobalVariableExpression::get(VMContext, GV, Expr);
   AllGVs.push_back(N);
   return N;
@@ -600,7 +608,7 @@
   return DIGlobalVariable::getTemporary(
              VMContext, cast_or_null<DIScope>(Context), Name, LinkageName, F,
              LineNumber, Ty, isLocalToUnit, false,
-             cast_or_null<DIDerivedType>(Decl), AlignInBits)
+             cast_or_null<DIDerivedType>(Decl), AlignInBits, nullptr)
       .release();
 }
 
Index: lib/IR/DebugInfoMetadata.cpp
===================================================================
--- lib/IR/DebugInfoMetadata.cpp
+++ lib/IR/DebugInfoMetadata.cpp
@@ -538,16 +538,17 @@
                           MDString *LinkageName, Metadata *File, unsigned Line,
                           Metadata *Type, bool IsLocalToUnit, bool IsDefinition,
                           Metadata *StaticDataMemberDeclaration,
-                          uint32_t AlignInBits, StorageType Storage,
-                          bool ShouldCreate) {
+                          uint32_t AlignInBits, Metadata *Unit,
+                          StorageType Storage, bool ShouldCreate) {
   assert(isCanonical(Name) && "Expected canonical MDString");
   assert(isCanonical(LinkageName) && "Expected canonical MDString");
   DEFINE_GETIMPL_LOOKUP(DIGlobalVariable,
                         (Scope, Name, LinkageName, File, Line, Type,
                          IsLocalToUnit, IsDefinition,
-                         StaticDataMemberDeclaration, AlignInBits));
+                         StaticDataMemberDeclaration, AlignInBits, Unit));
   Metadata *Ops[] = {
-      Scope, Name, File, Type, Name, LinkageName, StaticDataMemberDeclaration};
+      Scope, Name, File, Type, Name, LinkageName, StaticDataMemberDeclaration,
+      Unit};
   DEFINE_GETIMPL_STORE(DIGlobalVariable,
                        (Line, IsLocalToUnit, IsDefinition, AlignInBits),
                        Ops);
Index: lib/IR/LLVMContextImpl.h
===================================================================
--- lib/IR/LLVMContextImpl.h
+++ lib/IR/LLVMContextImpl.h
@@ -783,28 +783,30 @@
   MDString *Name;
   MDString *LinkageName;
   Metadata *File;
-  unsigned Line;
   Metadata *Type;
+  Metadata *StaticDataMemberDeclaration;
+  Metadata *Unit;
+  unsigned Line;
   bool IsLocalToUnit;
   bool IsDefinition;
-  Metadata *StaticDataMemberDeclaration;
   uint32_t AlignInBits;
 
   MDNodeKeyImpl(Metadata *Scope, MDString *Name, MDString *LinkageName,
                 Metadata *File, unsigned Line, Metadata *Type,
                 bool IsLocalToUnit, bool IsDefinition,
-                Metadata *StaticDataMemberDeclaration, uint32_t AlignInBits)
+                Metadata *StaticDataMemberDeclaration, uint32_t AlignInBits,
+                Metadata *Unit)
       : Scope(Scope), Name(Name), LinkageName(LinkageName), File(File),
-        Line(Line), Type(Type), IsLocalToUnit(IsLocalToUnit),
-        IsDefinition(IsDefinition),
-        StaticDataMemberDeclaration(StaticDataMemberDeclaration),
-        AlignInBits(AlignInBits) {}
+        Type(Type), StaticDataMemberDeclaration(StaticDataMemberDeclaration),
+        Unit(Unit), Line(Line), IsLocalToUnit(IsLocalToUnit),
+        IsDefinition(IsDefinition), AlignInBits(AlignInBits) {}
   MDNodeKeyImpl(const DIGlobalVariable *N)
       : Scope(N->getRawScope()), Name(N->getRawName()),
         LinkageName(N->getRawLinkageName()), File(N->getRawFile()),
-        Line(N->getLine()), Type(N->getRawType()),
-        IsLocalToUnit(N->isLocalToUnit()), IsDefinition(N->isDefinition()),
+        Type(N->getRawType()),
         StaticDataMemberDeclaration(N->getRawStaticDataMemberDeclaration()),
+        Unit(N->getRawUnit()), Line(N->getLine()),
+        IsLocalToUnit(N->isLocalToUnit()), IsDefinition(N->isDefinition()),
         AlignInBits(N->getAlignInBits()) {}
 
   bool isKeyOf(const DIGlobalVariable *RHS) const {
@@ -815,7 +817,7 @@
            IsDefinition == RHS->isDefinition() &&
            StaticDataMemberDeclaration ==
                RHS->getRawStaticDataMemberDeclaration() &&
-           AlignInBits == RHS->getAlignInBits();
+           AlignInBits == RHS->getAlignInBits() && Unit == RHS->getRawUnit();
   }
   unsigned getHashValue() const {
     // We do not use AlignInBits in hashing function here on purpose:
Index: lib/IR/Verifier.cpp
===================================================================
--- lib/IR/Verifier.cpp
+++ lib/IR/Verifier.cpp
@@ -658,9 +658,16 @@
   SmallVector<MDNode *, 1> MDs;
   GV.getMetadata(LLVMContext::MD_dbg, MDs);
   for (auto *MD : MDs) {
-    if (auto *GVE = dyn_cast<DIGlobalVariableExpression>(MD))
+    if (auto *GVE = dyn_cast<DIGlobalVariableExpression>(MD)) {
+      AssertDI(GVE->getVariable(), "missing DIGlobalVariable");
+      if (auto *GV = GVE->getVariable()) {
+        if (GV->isDistinct())
+          AssertDI(GV->getUnit(), "missing unit field");
+        else 
+          AssertDI(!GV->getUnit(), "unique variable with a unit field");
+      }
       visitDIGlobalVariableExpression(*GVE);
-    else
+    } else
       AssertDI(false, "!dbg attachment of global variable must be a "
                       "DIGlobalVariableExpression");
   }
@@ -671,7 +678,8 @@
   }
 
   // Walk any aggregate initializers looking for bitcasts between address spaces
-  visitConstantExprsRecursively(GV.getInitializer());
+  if (GV.hasInitializer())
+    visitConstantExprsRecursively(GV.getInitializer());
 
   visitGlobalValue(GV);
 }
@@ -1016,8 +1024,10 @@
   if (auto *Array = N.getRawGlobalVariables()) {
     AssertDI(isa<MDTuple>(Array), "invalid global variable list", &N, Array);
     for (Metadata *Op : N.getGlobalVariables()->operands()) {
-      AssertDI(Op && (isa<DIGlobalVariableExpression>(Op)),
-               "invalid global variable ref", &N, Op);
+      if (auto *GVE = dyn_cast_or_null<DIGlobalVariableExpression>(Op))
+        visitDIGlobalVariableExpression(*GVE);
+      else
+        AssertDI(false, "invalid global variable ref", &N, Op);
     }
   }
   if (auto *Array = N.getRawImportedEntities()) {
Index: test/Bitcode/DIGlobalVariable-unit.ll
===================================================================
--- /dev/null
+++ test/Bitcode/DIGlobalVariable-unit.ll
@@ -0,0 +1,23 @@
+; RUN: llvm-dis -o - %s.bc | FileCheck %s
+@g = common global i32 0, align 4, !dbg !0
+
+!llvm.dbg.cu = !{!2}
+!llvm.module.flags = !{!9, !10, !11}
+!llvm.ident = !{!12}
+
+!0 = !DIGlobalVariableExpression(var: !1)
+; CHECK: distinct !DIGlobalVariable(name: "g", {{.*}}, unit: ![[CU:[0-9]+]])
+!1 = distinct !DIGlobalVariable(name: "g", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true)
+; CHECK: ![[CU]] = distinct !DICompileUnit
+!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, imports: !5)
+!3 = !DIFile(filename: "t.c", directory: "/")
+!4 = !{!0}
+!5 = !{!6}
+!6 = !DIImportedEntity(tag: DW_TAG_imported_declaration, name: "h", scope: !2, entity: !7, line: 1)
+; CHECK: distinct !DIGlobalVariable(name: "h", {{.*}}, isDefinition: false)
+!7 = distinct !DIGlobalVariable(name: "h", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: false)
+!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!9 = !{i32 2, !"Dwarf Version", i32 4}
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!11 = !{i32 1, !"PIC Level", i32 2}
+!12 = !{!"clang version 4.0.0 (trunk 290265)"}
Index: test/Bitcode/diglobalvariable-3.8.ll
===================================================================
--- test/Bitcode/diglobalvariable-3.8.ll
+++ test/Bitcode/diglobalvariable-3.8.ll
@@ -10,7 +10,7 @@
 ; CHECK: !3 = !{!4}
 !3 = !{!4}
 ; CHECK: !4 = {{.*}}!DIGlobalVariableExpression(var: !5, expr: !8)
-; CHECK: !5 = !DIGlobalVariable(name: "c", scope: !0, file: !1, line: 1, type: !6, isLocal: false, isDefinition: true)
+; CHECK: !5 = !DIGlobalVariable(name: "c", scope: !0, file: !1, line: 1, type: !6, isLocal: false, isDefinition: true, unit: !0)
 ; CHECK: !8 = !DIExpression(DW_OP_constu, 42, DW_OP_stack_value)
 !4 = !DIGlobalVariable(name: "c", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, variable: i32 42)
 !5 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !6)
Index: test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
===================================================================
--- test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
+++ test/CodeGen/ARM/2011-01-19-MergedGlobalDbg.ll
@@ -19,6 +19,9 @@
 
 ; CHECK: DW_TAG_variable
 ; CHECK-NOT: DW_TAG
+; CHECK:    DW_AT_name {{.*}} "x5"
+; CHECK: DW_TAG_variable
+; CHECK-NOT: DW_TAG
 ; CHECK:    DW_AT_name {{.*}} "x1"
 ; CHECK-NOT: {{DW_TAG|NULL}}
 ; CHECK:    DW_AT_location [DW_FORM_exprloc]        (<0x5> 03 [[ADDR:.. .. .. ..]]   )
@@ -91,17 +94,17 @@
 !llvm.module.flags = !{!15}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "x1", scope: !2, file: !2, line: 3, type: !3, isLocal: true, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x1", scope: !2, file: !2, line: 3, type: !3, isLocal: true, isDefinition: true, unit: !12)
 !2 = !DIFile(filename: "foo.c", directory: "/tmp/")
 !3 = !DIBasicType(name: "_Bool", size: 8, align: 8, encoding: DW_ATE_boolean)
 !4 = !DIGlobalVariableExpression(var: !5)
-!5 = !DIGlobalVariable(name: "x2", scope: !2, file: !2, line: 6, type: !3, isLocal: true, isDefinition: true)
+!5 = distinct !DIGlobalVariable(name: "x2", scope: !2, file: !2, line: 6, type: !3, isLocal: true, isDefinition: true, unit: !12)
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = !DIGlobalVariable(name: "x3", scope: !2, file: !2, line: 9, type: !3, isLocal: true, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "x3", scope: !2, file: !2, line: 9, type: !3, isLocal: true, isDefinition: true, unit: !12)
 !8 = !DIGlobalVariableExpression(var: !9)
-!9 = !DIGlobalVariable(name: "x4", scope: !2, file: !2, line: 12, type: !3, isLocal: true, isDefinition: true)
+!9 = distinct !DIGlobalVariable(name: "x4", scope: !2, file: !2, line: 12, type: !3, isLocal: true, isDefinition: true, unit: !12)
 !10 = !DIGlobalVariableExpression(var: !11)
-!11 = !DIGlobalVariable(name: "x5", scope: !2, file: !2, line: 15, type: !3, isLocal: false, isDefinition: true)
+!11 = distinct !DIGlobalVariable(name: "x5", scope: !2, file: !2, line: 15, type: !3, isLocal: false, isDefinition: true, unit: !12)
 !12 = distinct !DICompileUnit(language: DW_LANG_C89, file: !2, producer: "4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2369.8)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !13, retainedTypes: !13, globals: !14, imports: !13)
 !13 = !{}
 !14 = !{!0, !4, !6, !8, !10}
Index: test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
===================================================================
--- test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
+++ test/CodeGen/ARM/2011-08-02-MergedGlobalDbg.ll
@@ -89,13 +89,13 @@
 !llvm.module.flags = !{!9}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "x1", scope: !2, file: !3, line: 4, type: !8, isLocal: true, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x1", scope: !2, file: !3, line: 4, type: !8, isLocal: true, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !4, globals: !5, imports: !4)
 !3 = !DIFile(filename: "ss3.c", directory: "/private/tmp")
 !4 = !{}
 !5 = !{!0, !6}
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = !DIGlobalVariable(name: "x2", scope: !2, file: !3, line: 7, type: !8, isLocal: true, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "x2", scope: !2, file: !3, line: 7, type: !8, isLocal: true, isDefinition: true, unit: !2)
 !8 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !9 = !{i32 1, !"Debug Info Version", i32 3}
 !10 = distinct !DISubprogram(name: "get1", scope: !3, file: !3, line: 5, type: !11, isLocal: false, isDefinition: true, scopeLine: 5, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: true, unit: !2, variables: !13)
Index: test/CodeGen/ARM/no-cfi.ll
===================================================================
--- test/CodeGen/ARM/no-cfi.ll
+++ test/CodeGen/ARM/no-cfi.ll
@@ -12,7 +12,7 @@
 !llvm.module.flags = !{!7, !8, !9, !10}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "f", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "f", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 4.0.0 (trunk 290216)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "test2.c", directory: "/tmp")
 !4 = !{}
Index: test/CodeGen/X86/dwarf-headers.ll
===================================================================
--- test/CodeGen/X86/dwarf-headers.ll
+++ test/CodeGen/X86/dwarf-headers.ll
@@ -95,7 +95,7 @@
 !llvm.ident = !{!12}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "s", scope: !2, file: !3, line: 5, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "s", scope: !2, file: !3, line: 5, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 5.0.0 (trunk 295942)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "t.cpp", directory: "/home/probinson/projects/scratch")
 !4 = !{}
Index: test/CodeGen/X86/machine-outliner-debuginfo.ll
===================================================================
--- test/CodeGen/X86/machine-outliner-debuginfo.ll
+++ test/CodeGen/X86/machine-outliner-debuginfo.ll
@@ -48,7 +48,7 @@
 !llvm.ident = !{!10}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 5.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "debug-test.c", directory: "dir")
 !4 = !{}
Index: test/DebugInfo/AMDGPU/variable-locations-dwarf-v1.ll
===================================================================
--- test/DebugInfo/AMDGPU/variable-locations-dwarf-v1.ll
+++ test/DebugInfo/AMDGPU/variable-locations-dwarf-v1.ll
@@ -56,13 +56,13 @@
 !llvm.ident = !{!12}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "GlobA", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "GlobA", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 5.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "variable-locations-dwarf-v1.cl", directory: "/some/random/directory")
 !4 = !{}
 !5 = !{!0, !6}
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = distinct !DIGlobalVariable(name: "GlobB", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "GlobB", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !9 = !{i32 2, i32 0}
 !10 = !{i32 2, !"Dwarf Version", i32 1}
Index: test/DebugInfo/AMDGPU/variable-locations.ll
===================================================================
--- test/DebugInfo/AMDGPU/variable-locations.ll
+++ test/DebugInfo/AMDGPU/variable-locations.ll
@@ -75,13 +75,13 @@
 !llvm.ident = !{!12}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "GlobA", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "GlobA", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 5.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "variable-locations.cl", directory: "/some/random/directory")
 !4 = !{}
 !5 = !{!0, !6}
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = distinct !DIGlobalVariable(name: "GlobB", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "GlobB", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !9 = !{i32 2, i32 0}
 !10 = !{i32 2, !"Dwarf Version", i32 2}
Index: test/DebugInfo/ARM/tls.ll
===================================================================
--- test/DebugInfo/ARM/tls.ll
+++ test/DebugInfo/ARM/tls.ll
@@ -24,7 +24,7 @@
 ; EMU-NOT: .long x(tlsldo)
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "x", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "tls.c", directory: "/tmp")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 3.5 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/Generic/accel-table-hash-collisions.ll
===================================================================
--- test/DebugInfo/Generic/accel-table-hash-collisions.ll
+++ test/DebugInfo/Generic/accel-table-hash-collisions.ll
@@ -70,34 +70,34 @@
 !llvm.ident = !{!32}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "ForceTopDown", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "ForceTopDown", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 3.7.0 (trunk 231548) (llvm/trunk 231547)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !4, globals: !5, imports: !4)
 !3 = !DIFile(filename: "hash-collisions.c", directory: "/tmp")
 !4 = !{}
 !5 = !{!0, !6, !9, !11, !13, !15, !17, !19, !21, !23, !25, !27}
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = !DIGlobalVariable(name: "_ZNSt3__116allocator_traitsINS_9allocatorINS_11__tree_nodeINS_12__value_typeIPN4llvm10BasicBlockEPNS4_10RegionNodeEEEPvEEEEE11__constructIS9_JNS_4pairIS6_S8_EEEEEvNS_17integral_constantIbLb1EEERSC_PT_DpOT0_", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "_ZNSt3__116allocator_traitsINS_9allocatorINS_11__tree_nodeINS_12__value_typeIPN4llvm10BasicBlockEPNS4_10RegionNodeEEEPvEEEEE11__constructIS9_JNS_4pairIS6_S8_EEEEEvNS_17integral_constantIbLb1EEERSC_PT_DpOT0_", scope: !2, file: !3, line: 2, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !8 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !9 = !DIGlobalVariableExpression(var: !10)
-!10 = !DIGlobalVariable(name: "_ZN5clang23DataRecursiveASTVisitorIN12_GLOBAL__N_124UnusedBackingIvarCheckerEE26TraverseCUDAKernelCallExprEPNS_18CUDAKernelCallExprE", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true)
+!10 = distinct !DIGlobalVariable(name: "_ZN5clang23DataRecursiveASTVisitorIN12_GLOBAL__N_124UnusedBackingIvarCheckerEE26TraverseCUDAKernelCallExprEPNS_18CUDAKernelCallExprE", scope: !2, file: !3, line: 3, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !11 = !DIGlobalVariableExpression(var: !12)
-!12 = !DIGlobalVariable(name: "_ZN4llvm16DenseMapIteratorIPNS_10MDLocationENS_6detail13DenseSetEmptyENS_10MDNodeInfoIS1_EENS3_12DenseSetPairIS2_EELb0EE23AdvancePastEmptyBucketsEv", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+!12 = distinct !DIGlobalVariable(name: "_ZN4llvm16DenseMapIteratorIPNS_10MDLocationENS_6detail13DenseSetEmptyENS_10MDNodeInfoIS1_EENS3_12DenseSetPairIS2_EELb0EE23AdvancePastEmptyBucketsEv", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !13 = !DIGlobalVariableExpression(var: !14)
-!14 = !DIGlobalVariable(name: "_ZNK4llvm12LivePhysRegs5printERNS_11raw_ostreamE", scope: !2, file: !3, line: 5, type: !8, isLocal: false, isDefinition: true)
+!14 = distinct !DIGlobalVariable(name: "_ZNK4llvm12LivePhysRegs5printERNS_11raw_ostreamE", scope: !2, file: !3, line: 5, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !15 = !DIGlobalVariableExpression(var: !16)
-!16 = !DIGlobalVariable(name: "_ZN4llvm15ScalarEvolution14getSignedRangeEPKNS_4SCEVE", scope: !2, file: !3, line: 6, type: !8, isLocal: false, isDefinition: true)
+!16 = distinct !DIGlobalVariable(name: "_ZN4llvm15ScalarEvolution14getSignedRangeEPKNS_4SCEVE", scope: !2, file: !3, line: 6, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !17 = !DIGlobalVariableExpression(var: !18)
-!18 = !DIGlobalVariable(name: "k1", scope: !2, file: !3, line: 7, type: !8, isLocal: false, isDefinition: true)
+!18 = distinct !DIGlobalVariable(name: "k1", scope: !2, file: !3, line: 7, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !19 = !DIGlobalVariableExpression(var: !20)
-!20 = !DIGlobalVariable(name: "is", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!20 = distinct !DIGlobalVariable(name: "is", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !21 = !DIGlobalVariableExpression(var: !22)
-!22 = !DIGlobalVariable(name: "setStmt", scope: !2, file: !3, line: 9, type: !8, isLocal: false, isDefinition: true)
+!22 = distinct !DIGlobalVariable(name: "setStmt", scope: !2, file: !3, line: 9, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !23 = !DIGlobalVariableExpression(var: !24)
-!24 = !DIGlobalVariable(name: "_ZN4llvm5TwineC1Ei", scope: !2, file: !3, line: 10, type: !8, isLocal: false, isDefinition: true)
+!24 = distinct !DIGlobalVariable(name: "_ZN4llvm5TwineC1Ei", scope: !2, file: !3, line: 10, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !25 = !DIGlobalVariableExpression(var: !26)
-!26 = !DIGlobalVariable(name: "_ZNK5clang12OverrideAttr5cloneERNS_10ASTContextE", scope: !2, file: !3, line: 11, type: !8, isLocal: false, isDefinition: true)
+!26 = distinct !DIGlobalVariable(name: "_ZNK5clang12OverrideAttr5cloneERNS_10ASTContextE", scope: !2, file: !3, line: 11, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !27 = !DIGlobalVariableExpression(var: !28)
-!28 = !DIGlobalVariable(name: "_ZN4llvm22MachineModuleInfoMachOD2Ev", scope: !2, file: !3, line: 12, type: !8, isLocal: false, isDefinition: true)
+!28 = distinct !DIGlobalVariable(name: "_ZN4llvm22MachineModuleInfoMachOD2Ev", scope: !2, file: !3, line: 12, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !29 = !{i32 2, !"Dwarf Version", i32 2}
 !30 = !{i32 2, !"Debug Info Version", i32 3}
 !31 = !{i32 1, !"PIC Level", i32 2}
Index: test/DebugInfo/MIR/X86/live-debug-values-spill.mir
===================================================================
--- test/DebugInfo/MIR/X86/live-debug-values-spill.mir
+++ test/DebugInfo/MIR/X86/live-debug-values-spill.mir
@@ -203,22 +203,22 @@
   !llvm.ident = !{!19}
   
   !0 = !DIGlobalVariableExpression(var: !1)
-  !1 = distinct !DIGlobalVariable(name: "glob0", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !1 = distinct !DIGlobalVariable(name: "glob0", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 5.0.0 (trunk 292962)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
   !3 = !DIFile(filename: "spill1.c", directory: "/home/test")
   !4 = !{}
   !5 = !{!0, !6, !9, !11, !13, !15}
   !6 = !DIGlobalVariableExpression(var: !7)
-  !7 = distinct !DIGlobalVariable(name: "glob1", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !7 = distinct !DIGlobalVariable(name: "glob1", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
   !9 = !DIGlobalVariableExpression(var: !10)
-  !10 = distinct !DIGlobalVariable(name: "glob2", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !10 = distinct !DIGlobalVariable(name: "glob2", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !11 = !DIGlobalVariableExpression(var: !12)
-  !12 = distinct !DIGlobalVariable(name: "glob3", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !12 = distinct !DIGlobalVariable(name: "glob3", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !13 = !DIGlobalVariableExpression(var: !14)
-  !14 = distinct !DIGlobalVariable(name: "glob4", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !14 = distinct !DIGlobalVariable(name: "glob4", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !15 = !DIGlobalVariableExpression(var: !16)
-  !16 = distinct !DIGlobalVariable(name: "glob5", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
+  !16 = distinct !DIGlobalVariable(name: "glob5", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true, unit: !2)
   !17 = !{i32 2, !"Dwarf Version", i32 4}
   !18 = !{i32 2, !"Debug Info Version", i32 3}
   !19 = !{!"clang version 5.0.0 (trunk 292962)"}
Index: test/DebugInfo/Mips/tls.ll
===================================================================
--- test/DebugInfo/Mips/tls.ll
+++ test/DebugInfo/Mips/tls.ll
@@ -11,7 +11,7 @@
 !llvm.ident = !{!9}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 4.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "tls.c", directory: "/tmp")
 !4 = !{}
Index: test/DebugInfo/PowerPC/tls-fission.ll
===================================================================
--- test/DebugInfo/PowerPC/tls-fission.ll
+++ test/DebugInfo/PowerPC/tls-fission.ll
@@ -24,7 +24,7 @@
 !llvm.module.flags = !{!7, !8}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "tls.cpp", directory: "/tmp")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 3.4 ", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "tls.dwo", emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/PowerPC/tls.ll
===================================================================
--- test/DebugInfo/PowerPC/tls.ll
+++ test/DebugInfo/PowerPC/tls.ll
@@ -20,7 +20,7 @@
 !llvm.module.flags = !{!7, !8}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "tls.cpp", directory: "/tmp")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 3.4 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/X86/FrameIndexExprs.ll
===================================================================
--- test/DebugInfo/X86/FrameIndexExprs.ll
+++ test/DebugInfo/X86/FrameIndexExprs.ll
@@ -48,13 +48,13 @@
 !llvm.module.flags = !{!9, !10, !11}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "f", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "f", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "PR31381.c", directory: "/")
 !4 = !{}
 !5 = !{!0, !6}
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = distinct !DIGlobalVariable(name: "h", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "h", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true, unit: !2)
 !8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !9 = !{i32 2, !"Dwarf Version", i32 4}
 !10 = !{i32 2, !"Debug Info Version", i32 3}
Index: test/DebugInfo/X86/arange-and-stub.ll
===================================================================
--- test/DebugInfo/X86/arange-and-stub.ll
+++ test/DebugInfo/X86/arange-and-stub.ll
@@ -34,7 +34,7 @@
 !llvm.module.flags = !{!15, !16}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "zed", scope: !2, file: !6, line: 6, type: !7, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "zed", scope: !2, file: !6, line: 6, type: !7, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 3.7.0 (trunk 234308) (llvm/trunk 234310)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !4, globals: !5, imports: !4)
 !3 = !DIFile(filename: "/Users/espindola/llvm/<stdin>", directory: "/Users/espindola/llvm/build")
 !4 = !{}
Index: test/DebugInfo/X86/arange.ll
===================================================================
--- test/DebugInfo/X86/arange.ll
+++ test/DebugInfo/X86/arange.ll
@@ -32,7 +32,7 @@
 !llvm.ident = !{!14}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "f", scope: null, file: !2, line: 6, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "f", scope: null, file: !2, line: 6, type: !3, isLocal: false, isDefinition: true, unit: !9)
 !2 = !DIFile(filename: "simple.cpp", directory: "/tmp/dbginfo")
 !3 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo<&i>", file: !2, line: 3, size: 8, align: 8, elements: !4, templateParams: !5, identifier: "_ZTS3fooIXadL_Z1iEEE")
 !4 = !{}
Index: test/DebugInfo/X86/debug-info-static-member.ll
===================================================================
--- test/DebugInfo/X86/debug-info-static-member.ll
+++ test/DebugInfo/X86/debug-info-static-member.ll
@@ -67,7 +67,7 @@
 !llvm.module.flags = !{!25}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "a", linkageName: "_ZN1C1aE", scope: null, file: !2, line: 14, type: !3, isLocal: false, isDefinition: true, declaration: !4)
+!1 = distinct !DIGlobalVariable(name: "a", linkageName: "_ZN1C1aE", scope: null, file: !2, line: 14, type: !3, isLocal: false, isDefinition: true, declaration: !4, unit: !22)
 !2 = !DIFile(filename: "/usr/local/google/home/blaikie/Development/llvm/src/tools/clang/test/CodeGenCXX/debug-info-static-member.cpp", directory: "/home/blaikie/local/Development/llvm/build/clang/x86-64/Debug/llvm")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !5, file: !2, line: 3, baseType: !3, flags: DIFlagPrivate | DIFlagStaticMember)
@@ -85,9 +85,9 @@
 !16 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !3)
 !17 = !DIDerivedType(tag: DW_TAG_member, name: "d", scope: !5, file: !2, line: 11, baseType: !3, size: 32, align: 32, flags: DIFlagPublic)
 !18 = !DIGlobalVariableExpression(var: !19)
-!19 = !DIGlobalVariable(name: "b", linkageName: "_ZN1C1bE", scope: null, file: !2, line: 15, type: !3, isLocal: false, isDefinition: true, declaration: !10)
+!19 = distinct !DIGlobalVariable(name: "b", linkageName: "_ZN1C1bE", scope: null, file: !2, line: 15, type: !3, isLocal: false, isDefinition: true, declaration: !10, unit: !22)
 !20 = !DIGlobalVariableExpression(var: !21)
-!21 = !DIGlobalVariable(name: "c", linkageName: "_ZN1C1cE", scope: null, file: !2, line: 16, type: !3, isLocal: false, isDefinition: true, declaration: !14)
+!21 = distinct !DIGlobalVariable(name: "c", linkageName: "_ZN1C1cE", scope: null, file: !2, line: 16, type: !3, isLocal: false, isDefinition: true, declaration: !14, unit: !22)
 !22 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 3.3 (trunk 171914)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !23, retainedTypes: !23, globals: !24, imports: !23)
 !23 = !{}
 !24 = !{!0, !18, !20}
Index: test/DebugInfo/X86/dwarf-aranges-no-dwarf-labels.ll
===================================================================
--- test/DebugInfo/X86/dwarf-aranges-no-dwarf-labels.ll
+++ test/DebugInfo/X86/dwarf-aranges-no-dwarf-labels.ll
@@ -61,7 +61,7 @@
 !llvm.module.flags = !{!7, !8}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "global", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "global", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "tmp/debug_ranges/a.cc", directory: "/")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 3.4 (191881)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/X86/dwarf-aranges.ll
===================================================================
--- test/DebugInfo/X86/dwarf-aranges.ll
+++ test/DebugInfo/X86/dwarf-aranges.ll
@@ -61,13 +61,13 @@
 !llvm.module.flags = !{!11, !12}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "some_data", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "some_data", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !8)
 !2 = !DIFile(filename: "test.c", directory: "/home/kayamon")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = !DIGlobalVariableExpression(var: !5)
-!5 = !DIGlobalVariable(name: "some_other", scope: null, file: !2, line: 3, type: !3, isLocal: false, isDefinition: true)
+!5 = distinct !DIGlobalVariable(name: "some_other", scope: null, file: !2, line: 3, type: !3, isLocal: false, isDefinition: true, unit: !8)
 !6 = !DIGlobalVariableExpression(var: !7)
-!7 = !DIGlobalVariable(name: "some_bss", scope: null, file: !2, line: 2, type: !3, isLocal: false, isDefinition: true)
+!7 = distinct !DIGlobalVariable(name: "some_bss", scope: null, file: !2, line: 2, type: !3, isLocal: false, isDefinition: true, unit: !8)
 !8 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 3.4 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !9, retainedTypes: !9, globals: !10, imports: !9)
 !9 = !{}
 !10 = !{!0, !4, !6}
Index: test/DebugInfo/X86/dwarf-public-names.ll
===================================================================
--- test/DebugInfo/X86/dwarf-public-names.ll
+++ test/DebugInfo/X86/dwarf-public-names.ll
@@ -104,7 +104,7 @@
 !llvm.module.flags = !{!22}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "static_member_variable", linkageName: "_ZN1C22static_member_variableE", scope: !2, file: !3, line: 7, type: !6, isLocal: false, isDefinition: true, declaration: !5)
+!1 = distinct !DIGlobalVariable(name: "static_member_variable", linkageName: "_ZN1C22static_member_variableE", scope: !2, file: !3, line: 7, type: !6, isLocal: false, isDefinition: true, declaration: !5, unit: !20)
 !2 = !DICompositeType(tag: DW_TAG_structure_type, name: "C", file: !3, line: 1, size: 8, elements: !4)
 !3 = !DIFile(filename: "dwarf-public-names.cpp", directory: "/usr2/kparzysz/s.hex/t")
 !4 = !{!5, !7, !12}
@@ -119,9 +119,9 @@
 !13 = !DISubroutineType(types: !14)
 !14 = !{!6}
 !15 = !DIGlobalVariableExpression(var: !16)
-!16 = !DIGlobalVariable(name: "global_variable", scope: null, file: !3, line: 17, type: !2, isLocal: false, isDefinition: true) ; previously: invalid DW_TAG_base_type
+!16 = distinct !DIGlobalVariable(name: "global_variable", scope: null, file: !3, line: 17, type: !2, isLocal: false, isDefinition: true, unit: !20) ; previously: invalid DW_TAG_base_type
 !17 = !DIGlobalVariableExpression(var: !18)
-!18 = !DIGlobalVariable(name: "global_namespace_variable", linkageName: "_ZN2ns25global_namespace_variableE", scope: !19, file: !3, line: 27, type: !6, isLocal: false, isDefinition: true)
+!18 = distinct !DIGlobalVariable(name: "global_namespace_variable", linkageName: "_ZN2ns25global_namespace_variableE", scope: !19, file: !3, line: 27, type: !6, isLocal: false, isDefinition: true, unit: !20)
 !19 = !DINamespace(name: "ns", scope: null, file: !3, line: 23)
 !20 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 3.3 (http://llvm.org/git/clang.git a09cd8103a6a719cb2628cdf0c91682250a17bd2) (http://llvm.org/git/llvm.git 47d03cec0afca0c01ae42b82916d1d731716cd20)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !11, retainedTypes: !11, globals: !21, imports: !11) ; previously: invalid DW_TAG_base_type
 !21 = !{!0, !15, !17}
Index: test/DebugInfo/X86/fission-cu.ll
===================================================================
--- test/DebugInfo/X86/fission-cu.ll
+++ test/DebugInfo/X86/fission-cu.ll
@@ -11,7 +11,7 @@
 !llvm.module.flags = !{!7}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "a", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "a", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "baz.c", directory: "/usr/local/google/home/echristo/tmp")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 3.3 (trunk 169021) (llvm/trunk 169020)", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "baz.dwo", emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/X86/gnu-public-names-tu.ll
===================================================================
--- test/DebugInfo/X86/gnu-public-names-tu.ll
+++ test/DebugInfo/X86/gnu-public-names-tu.ll
@@ -38,7 +38,7 @@
 !llvm.ident = !{!13}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 8, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !3, line: 8, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 5.0.0 (trunk 293904) (llvm/trunk 293908)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "type.cpp", directory: "/tmp/dbginfo")
 !4 = !{}
Index: test/DebugInfo/X86/gnu-public-names.ll
===================================================================
--- test/DebugInfo/X86/gnu-public-names.ll
+++ test/DebugInfo/X86/gnu-public-names.ll
@@ -301,7 +301,7 @@
 !llvm.ident = !{!50}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "static_member_variable", linkageName: "_ZN1C22static_member_variableE", scope: !2, file: !3, line: 7, type: !9, isLocal: false, isDefinition: true, declaration: !8)
+!1 = distinct !DIGlobalVariable(name: "static_member_variable", linkageName: "_ZN1C22static_member_variableE", scope: !2, file: !3, line: 7, type: !9, isLocal: false, isDefinition: true, declaration: !8, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 3.7.0 (trunk 234897) (llvm/trunk 234911)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !5, globals: !21, imports: !44)
 !3 = !DIFile(filename: "gnu-public-names.cpp", directory: "/tmp/dbginfo")
 !4 = !{}
@@ -323,30 +323,30 @@
 !20 = !DIDerivedType(tag: DW_TAG_member, name: "A", scope: !17, file: !3, line: 30, baseType: !9, size: 32, align: 32)
 !21 = !{!0, !22, !24, !26, !28, !34, !37, !40}
 !22 = !DIGlobalVariableExpression(var: !23)
-!23 = !DIGlobalVariable(name: "global_variable", scope: !2, file: !3, line: 17, type: !6, isLocal: false, isDefinition: true)
+!23 = distinct !DIGlobalVariable(name: "global_variable", scope: !2, file: !3, line: 17, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !24 = !DIGlobalVariableExpression(var: !25)
-!25 = !DIGlobalVariable(name: "global_namespace_variable", linkageName: "_ZN2ns25global_namespace_variableE", scope: !18, file: !3, line: 27, type: !9, isLocal: false, isDefinition: true)
+!25 = distinct !DIGlobalVariable(name: "global_namespace_variable", linkageName: "_ZN2ns25global_namespace_variableE", scope: !18, file: !3, line: 27, type: !9, isLocal: false, isDefinition: true, unit: !2)
 !26 = !DIGlobalVariableExpression(var: !27)
-!27 = !DIGlobalVariable(name: "d", linkageName: "_ZN2ns1dE", scope: !18, file: !3, line: 31, type: !17, isLocal: false, isDefinition: true)
+!27 = distinct !DIGlobalVariable(name: "d", linkageName: "_ZN2ns1dE", scope: !18, file: !3, line: 31, type: !17, isLocal: false, isDefinition: true, unit: !2)
 !28 = !DIGlobalVariableExpression(var: !29)
-!29 = !DIGlobalVariable(name: "z", scope: !30, file: !3, line: 41, type: !9, isLocal: true, isDefinition: true)
+!29 = distinct !DIGlobalVariable(name: "z", scope: !30, file: !3, line: 41, type: !9, isLocal: true, isDefinition: true, unit: !2)
 !30 = distinct !DISubprogram(name: "f3", linkageName: "_Z2f3v", scope: !3, file: !3, line: 40, type: !31, isLocal: false, isDefinition: true, scopeLine: 40, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
 !31 = !DISubroutineType(types: !32)
 !32 = !{!33}
 !33 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !9, size: 64, align: 64)
 !34 = !DIGlobalVariableExpression(var: !35)
-!35 = !DIGlobalVariable(name: "i", linkageName: "_ZN12_GLOBAL__N_11iE", scope: !36, file: !3, line: 37, type: !9, isLocal: true, isDefinition: true)
+!35 = distinct !DIGlobalVariable(name: "i", linkageName: "_ZN12_GLOBAL__N_11iE", scope: !36, file: !3, line: 37, type: !9, isLocal: true, isDefinition: true, unit: !2)
 !36 = !DINamespace(scope: null, file: !3, line: 36)
 !37 = !DIGlobalVariableExpression(var: !38)
-!38 = !DIGlobalVariable(name: "b", linkageName: "_ZN12_GLOBAL__N_15inner1bE", scope: !39, file: !3, line: 47, type: !9, isLocal: true, isDefinition: true)
+!38 = distinct !DIGlobalVariable(name: "b", linkageName: "_ZN12_GLOBAL__N_15inner1bE", scope: !39, file: !3, line: 47, type: !9, isLocal: true, isDefinition: true, unit: !2)
 !39 = !DINamespace(name: "inner", scope: !36, file: !3, line: 46)
 !40 = !DIGlobalVariableExpression(var: !41)
-!41 = !DIGlobalVariable(name: "c", linkageName: "_ZN5outer12_GLOBAL__N_11cE", scope: !42, file: !3, line: 53, type: !9, isLocal: true, isDefinition: true)
+!41 = distinct !DIGlobalVariable(name: "c", linkageName: "_ZN5outer12_GLOBAL__N_11cE", scope: !42, file: !3, line: 53, type: !9, isLocal: true, isDefinition: true, unit: !2)
 !42 = !DINamespace(scope: !43, file: !3, line: 52)
 !43 = !DINamespace(name: "outer", scope: null, file: !3, line: 51)
 !44 = !{!45, !47}
 !45 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !2, entity: !46, line: 34)
-!46 = !DIGlobalVariable(name: "global_namespace_variable_decl", linkageName: "_ZN2ns30global_namespace_variable_declE", scope: !18, file: !3, line: 28, type: !9, isLocal: false, isDefinition: false)
+!46 = distinct !DIGlobalVariable(name: "global_namespace_variable_decl", linkageName: "_ZN2ns30global_namespace_variable_declE", scope: !18, file: !3, line: 28, type: !9, isLocal: false, isDefinition: false, unit: !2)
 !47 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !43, entity: !42, line: 43)
 !48 = !{i32 2, !"Dwarf Version", i32 4}
 !49 = !{i32 2, !"Debug Info Version", i32 3}
Index: test/DebugInfo/X86/multiple-aranges.ll
===================================================================
--- test/DebugInfo/X86/multiple-aranges.ll
+++ test/DebugInfo/X86/multiple-aranges.ll
@@ -42,11 +42,11 @@
 !llvm.module.flags = !{!12, !13}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "kittens", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "kittens", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !7)
 !2 = !DIFile(filename: "test1.c", directory: "/home/kayamon")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = !DIGlobalVariableExpression(var: !5)
-!5 = !DIGlobalVariable(name: "rainbows", scope: null, file: !6, line: 1, type: !3, isLocal: false, isDefinition: true)
+!5 = distinct !DIGlobalVariable(name: "rainbows", scope: null, file: !6, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !10)
 !6 = !DIFile(filename: "test2.c", directory: "/home/kayamon")
 !7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 3.4 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !8, retainedTypes: !8, globals: !9, imports: !8)
 !8 = !{}
Index: test/DebugInfo/X86/split-global.ll
===================================================================
--- test/DebugInfo/X86/split-global.ll
+++ test/DebugInfo/X86/split-global.ll
@@ -35,7 +35,7 @@
 !llvm.dbg.cu = !{!1}
 !llvm.module.flags = !{!10, !11}
 
-!0 = distinct !DIGlobalVariable(name: "point", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true)
+!0 = distinct !DIGlobalVariable(name: "point", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, unit: !1)
 !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !4)
 !2 = !DIFile(filename: "g.c", directory: "/")
 !3 = !{}
@@ -52,7 +52,7 @@
 !14 = !DIGlobalVariableExpression(var: !16, expr: !DIExpression(DW_OP_LLVM_fragment,  0, 32))
 !15 = !DIGlobalVariableExpression(var: !16, expr: !DIExpression(DW_OP_constu, 2,
                                              DW_OP_stack_value, DW_OP_LLVM_fragment, 32, 32))
-!16 = distinct !DIGlobalVariable(name: "part_const", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true)
+!16 = distinct !DIGlobalVariable(name: "part_const", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, unit: !1)
 !17 = !DIGlobalVariableExpression(var: !19, expr: !DIExpression(DW_OP_constu, 1,
                                              DW_OP_stack_value, DW_OP_LLVM_fragment,  0, 32))
 !18 = !DIGlobalVariableExpression(var: !19, expr: !DIExpression(DW_OP_constu, 2,
Index: test/DebugInfo/X86/stack-value-dwarf4.ll
===================================================================
--- test/DebugInfo/X86/stack-value-dwarf4.ll
+++ test/DebugInfo/X86/stack-value-dwarf4.ll
@@ -29,10 +29,9 @@
 !3 = !DIExpression(DW_OP_constu, 4, DW_OP_constu, 4, DW_OP_stack_value)
 !4 = !DIFile(filename: "<stdin>", directory: "/")
 !5 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
-
 !6 = !{i32 2, !"Dwarf Version", i32 2}
 !7 = !{i32 2, !"Debug Info Version", i32 3}
-!8 = distinct !DIGlobalVariable(name: "a", scope: null, isLocal: false, isDefinition: true, type: !5)
+!8 = distinct !DIGlobalVariable(name: "a", scope: null, isLocal: false, isDefinition: true, type: !5, unit: !0)
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!6, !7}
Index: test/DebugInfo/X86/static_member_array.ll
===================================================================
--- test/DebugInfo/X86/static_member_array.ll
+++ test/DebugInfo/X86/static_member_array.ll
@@ -49,13 +49,13 @@
 !llvm.ident = !{!22}
 
 !0 = distinct !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "fully_specified", linkageName: "_ZN1A15fully_specifiedE", scope: !2, file: !3, line: 7, type: !9, isLocal: false, isDefinition: true, declaration: !15)
+!1 = distinct !DIGlobalVariable(name: "fully_specified", linkageName: "_ZN1A15fully_specifiedE", scope: !2, file: !3, line: 7, type: !9, isLocal: false, isDefinition: true, declaration: !15, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 4.0.0 (trunk 286129) (llvm/trunk 286128)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "static_member_array.cpp", directory: "/Volumes/Data/radar/28706946")
 !4 = !{}
 !5 = !{!0, !6}
 !6 = distinct !DIGlobalVariableExpression(var: !7)
-!7 = !DIGlobalVariable(name: "smem", linkageName: "_ZN1A4smemE", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true, declaration: !12)
+!7 = distinct !DIGlobalVariable(name: "smem", linkageName: "_ZN1A4smemE", scope: !2, file: !3, line: 8, type: !8, isLocal: false, isDefinition: true, declaration: !12, unit: !2)
 !8 = !DICompositeType(tag: DW_TAG_array_type, baseType: !9, size: 128, elements: !10)
 !9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 !10 = !{!11}
Index: test/DebugInfo/X86/stringpool.ll
===================================================================
--- test/DebugInfo/X86/stringpool.ll
+++ test/DebugInfo/X86/stringpool.ll
@@ -9,7 +9,7 @@
 !llvm.module.flags = !{!7}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "yyyy", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "yyyy", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !4)
 !2 = !DIFile(filename: "z.c", directory: "/home/nicholas")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang version 3.1 (trunk 143009)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !5, retainedTypes: !5, globals: !6, imports: !5)
Index: test/DebugInfo/X86/tls.ll
===================================================================
--- test/DebugInfo/X86/tls.ll
+++ test/DebugInfo/X86/tls.ll
@@ -112,11 +112,11 @@
 !llvm.ident = !{!11}
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "tls", scope: null, file: !2, line: 1, type: !3, isLocal: false, isDefinition: true, unit: !6)
 !2 = !DIFile(filename: "tls.cpp", directory: "/tmp/dbginfo")
 !3 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !4 = !DIGlobalVariableExpression(var: !5)
-!5 = !DIGlobalVariable(name: "glbl", scope: null, file: !2, line: 2, type: !3, isLocal: false, isDefinition: true)
+!5 = distinct !DIGlobalVariable(name: "glbl", scope: null, file: !2, line: 2, type: !3, isLocal: false, isDefinition: true, unit: !6)
 !6 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 3.5 ", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "-.dwo", emissionKind: FullDebug, enums: !7, retainedTypes: !7, globals: !8, imports: !7)
 !7 = !{}
 !8 = !{!0, !4}
Index: test/Linker/debug-info-global-var.ll
===================================================================
--- test/Linker/debug-info-global-var.ll
+++ test/Linker/debug-info-global-var.ll
@@ -22,4 +22,4 @@
 !7 = !{i32 2, !"Debug Info Version", i32 3}
 !8 = !{i32 1, !"PIC Level", i32 2}
 !9 = !{!"clang version 4.0.0 (trunk 286129) (llvm/trunk 286128)"}
-!10 = distinct !DIGlobalVariable(name: "g", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true)
+!10 = distinct !DIGlobalVariable(name: "g", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true, unit: !1)
Index: test/Transforms/ConstantMerge/merge-dbg.ll
===================================================================
--- test/Transforms/ConstantMerge/merge-dbg.ll
+++ test/Transforms/ConstantMerge/merge-dbg.ll
@@ -19,7 +19,7 @@
 ; CHECK: [[VB]] = distinct !DIGlobalVariable(name: "x"
 
 !0 = !DIGlobalVariableExpression(var: !1)
-!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
+!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, unit: !2)
 !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 5.0.0 (trunk 297227) (llvm/trunk 297234)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
 !3 = !DIFile(filename: "1.cc", directory: "/build")
 !4 = !{}
@@ -29,4 +29,4 @@
 !8 = !{i32 2, !"Debug Info Version", i32 3}
 
 !9 = !DIGlobalVariableExpression(var: !10)
-!10 = distinct !DIGlobalVariable(name: "y", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
+!10 = distinct !DIGlobalVariable(name: "y", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true, unit: !2)
Index: test/Verifier/DIGlobalVariable-no-unit.ll
===================================================================
--- /dev/null
+++ test/Verifier/DIGlobalVariable-no-unit.ll
@@ -0,0 +1,15 @@
+; RUN: not opt -S <%s 2>&1| FileCheck %s
+
+; CHECK: missing unit field
+@g = common global i32 0, align 4, !dbg !3
+
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!6, !7}
+
+!0 = distinct !DIGlobalVariable(name: "g", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true)
+!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, emissionKind: FullDebug)
+!2 = !DIFile(filename: "a.c", directory: "/")
+!3 = !DIGlobalVariableExpression(var: !0)
+!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!6 = !{i32 2, !"Dwarf Version", i32 4}
+!7 = !{i32 2, !"Debug Info Version", i32 3}
Index: test/tools/llvm-objdump/Hexagon/source-interleave-hexagon.ll
===================================================================
--- test/tools/llvm-objdump/Hexagon/source-interleave-hexagon.ll
+++ test/tools/llvm-objdump/Hexagon/source-interleave-hexagon.ll
@@ -45,7 +45,7 @@
 !1 = !DIFile(filename: "source-interleave-hexagon.c", directory: "SRC_COMPDIR")
 !2 = !{}
 !3 = !{!4}
-!4 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true))
+!4 = !DIGlobalVariableExpression(var: !24)
 !5 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !6 = !{i32 2, !"Dwarf Version", i32 4}
 !7 = !{i32 2, !"Debug Info Version", i32 3}
@@ -65,6 +65,7 @@
 !21 = !DILocation(line: 8, column: 15, scope: !14)
 !22 = !DILocation(line: 8, column: 13, scope: !14)
 !23 = !DILocation(line: 8, column: 3, scope: !14)
+!24 = distinct !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, unit: !0)
 ; LINES: main:
 ; LINES-NEXT: SRC_COMPDIR/source-interleave-hexagon.c:6
 
Index: test/tools/llvm-objdump/X86/source-interleave-x86_64.ll
===================================================================
--- test/tools/llvm-objdump/X86/source-interleave-x86_64.ll
+++ test/tools/llvm-objdump/X86/source-interleave-x86_64.ll
@@ -46,7 +46,7 @@
 !1 = !DIFile(filename: "source-interleave-x86_64.c", directory: "SRC_COMPDIR")
 !2 = !{}
 !3 = !{!4}
-!4 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true))
+!4 = distinct !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true)
 !5 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !6 = !{i32 2, !"Dwarf Version", i32 4}
 !7 = !{i32 2, !"Debug Info Version", i32 3}
Index: unittests/IR/MetadataTest.cpp
===================================================================
--- unittests/IR/MetadataTest.cpp
+++ unittests/IR/MetadataTest.cpp
@@ -1848,10 +1848,11 @@
   DIDerivedType *StaticDataMemberDeclaration =
       cast<DIDerivedType>(getDerivedType());
   uint32_t AlignInBits = 8;
+  DICompileUnit *Unit = getUnit();
 
-  auto *N = DIGlobalVariable::get(Context, Scope, Name, LinkageName, File, Line,
-                                  Type, IsLocalToUnit, IsDefinition,
-                                  StaticDataMemberDeclaration, AlignInBits);
+  auto *N = DIGlobalVariable::get(
+      Context, Scope, Name, LinkageName, File, Line, Type, IsLocalToUnit,
+      IsDefinition, StaticDataMemberDeclaration, AlignInBits, Unit);
   EXPECT_EQ(dwarf::DW_TAG_variable, N->getTag());
   EXPECT_EQ(Scope, N->getScope());
   EXPECT_EQ(Name, N->getName());
@@ -1863,46 +1864,56 @@
   EXPECT_EQ(IsDefinition, N->isDefinition());
   EXPECT_EQ(StaticDataMemberDeclaration, N->getStaticDataMemberDeclaration());
   EXPECT_EQ(AlignInBits, N->getAlignInBits());
+  EXPECT_EQ(Unit, N->getUnit());
   EXPECT_EQ(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                      Line, Type, IsLocalToUnit, IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits));
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     Unit));
 
-  EXPECT_NE(N,
-            DIGlobalVariable::get(Context, getSubprogram(), Name, LinkageName,
-                                  File, Line, Type, IsLocalToUnit, IsDefinition,
-                                  StaticDataMemberDeclaration, AlignInBits));
+  EXPECT_NE(
+      N, DIGlobalVariable::get(Context, getSubprogram(), Name, LinkageName,
+                               File, Line, Type, IsLocalToUnit, IsDefinition,
+                               StaticDataMemberDeclaration, AlignInBits, Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, "other", LinkageName, File,
                                      Line, Type, IsLocalToUnit, IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits));
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, "other", File, Line,
                                      Type, IsLocalToUnit, IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits));
-  EXPECT_NE(N,
-            DIGlobalVariable::get(Context, Scope, Name, LinkageName, getFile(),
-                                  Line, Type, IsLocalToUnit, IsDefinition,
-                                  StaticDataMemberDeclaration, AlignInBits));
-  EXPECT_NE(N,
-            DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
-                                  Line + 1, Type, IsLocalToUnit, IsDefinition,
-                                  StaticDataMemberDeclaration, AlignInBits));
-  EXPECT_NE(N,
-            DIGlobalVariable::get(Context, Scope, Name, LinkageName, File, Line,
-                                  getDerivedType(), IsLocalToUnit, IsDefinition,
-                                  StaticDataMemberDeclaration, AlignInBits));
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     Unit));
+  EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName,
+                                     getFile(), Line, Type, IsLocalToUnit,
+                                     IsDefinition, StaticDataMemberDeclaration,
+                                     AlignInBits, Unit));
+  EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
+                                     Line + 1, Type, IsLocalToUnit,
+                                     IsDefinition, StaticDataMemberDeclaration,
+                                     AlignInBits, Unit));
+  EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
+                                     Line, getDerivedType(), IsLocalToUnit,
+                                     IsDefinition, StaticDataMemberDeclaration,
+                                     AlignInBits, Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                      Line, Type, !IsLocalToUnit, IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits));
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                      Line, Type, IsLocalToUnit, !IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits));
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                      Line, Type, IsLocalToUnit, IsDefinition,
                                      cast<DIDerivedType>(getDerivedType()),
-                                     AlignInBits));
+                                     AlignInBits, Unit));
   EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                      Line, Type, IsLocalToUnit, IsDefinition,
                                      StaticDataMemberDeclaration,
-                                     (AlignInBits << 1)));
+                                     (AlignInBits << 1), Unit));
+  EXPECT_NE(N, DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
+                                     Line, Type, IsLocalToUnit, IsDefinition,
+                                     StaticDataMemberDeclaration, AlignInBits,
+                                     nullptr));
 
   TempDIGlobalVariable Temp = N->clone();
   EXPECT_EQ(N, MDNode::replaceWithUniqued(std::move(Temp)));
@@ -1924,13 +1935,14 @@
   DIDerivedType *StaticDataMemberDeclaration =
       cast<DIDerivedType>(getDerivedType());
   uint32_t AlignInBits = 8;
+  DICompileUnit *Unit = getUnit();
 
   auto *Var = DIGlobalVariable::get(Context, Scope, Name, LinkageName, File,
                                     Line, Type, IsLocalToUnit, IsDefinition,
-                                    StaticDataMemberDeclaration, AlignInBits);
+                                    StaticDataMemberDeclaration, AlignInBits, Unit);
   auto *Var2 = DIGlobalVariable::get(Context, Scope, "other", LinkageName, File,
                                      Line, Type, IsLocalToUnit, IsDefinition,
-                                     StaticDataMemberDeclaration, AlignInBits);
+                                     StaticDataMemberDeclaration, AlignInBits, Unit);
   auto *N = DIGlobalVariableExpression::get(Context, Var, Expr);
 
   EXPECT_EQ(Var, N->getVariable());