diff --git a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
index bf794f7..2aaa85a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -479,20 +479,6 @@
 }
 
 //===----------------------------------------------------------------------===//
-// DIETypeSignature Implementation
-//===----------------------------------------------------------------------===//
-void DIETypeSignature::EmitValue(const AsmPrinter *Asm,
-                                 dwarf::Form Form) const {
-  assert(Form == dwarf::DW_FORM_ref_sig8);
-  Asm->OutStreamer->EmitIntValue(Unit->getTypeSignature(), 8);
-}
-
-LLVM_DUMP_METHOD
-void DIETypeSignature::print(raw_ostream &O) const {
-  O << format("Type Unit: 0x%lx", Unit->getTypeSignature());
-}
-
-//===----------------------------------------------------------------------===//
 // DIELoc Implementation
 //===----------------------------------------------------------------------===//
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
index 0201065..91684c2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
@@ -353,7 +353,6 @@
   case DIEValue::isExpr:
   case DIEValue::isLabel:
   case DIEValue::isDelta:
-  case DIEValue::isTypeSignature:
     llvm_unreachable("Add support for additional value types.");
   }
 }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index cad3b2a..9dd5040 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -19,7 +19,7 @@
 DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
                                    AsmPrinter *A, DwarfDebug *DW,
                                    DwarfFile *DWU)
-    : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU),
+    : DwarfUnit(dwarf::DW_TAG_compile_unit, Node, A, DW, DWU), UniqueID(UID),
       Skeleton(nullptr), BaseAddress(nullptr) {
   insertDIE(Node, &getUnitDie());
   MacroLabelBegin = Asm->createTempSymbol("cu_macro_begin");
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 2c89f500..bacf87d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -29,6 +29,12 @@
 class LexicalScope;
 
 class DwarfCompileUnit : public DwarfUnit {
+  /// A numeric ID unique among all CUs in the module
+  unsigned UniqueID;
+
+  /// Offset of the UnitDie from beginning of debug info section.
+  unsigned DebugInfoOffset = 0;
+
   /// The attribute index of DW_AT_stmt_list in the compile unit DIE, avoiding
   /// the need to search for it in applyStmtList.
   DIE::value_iterator StmtListValue;
@@ -77,6 +83,10 @@
   DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
                    DwarfDebug *DW, DwarfFile *DWU);
 
+  unsigned getUniqueID() const { return UniqueID; }
+  unsigned getDebugInfoOffset() const { return DebugInfoOffset; }
+  void setDebugInfoOffset(unsigned DbgInfoOff) { DebugInfoOffset = DbgInfoOff; }
+
   DwarfCompileUnit *getSkeleton() const {
     return Skeleton;
   }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index ec7329e..9b37682 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1628,9 +1628,10 @@
   }
 
   // Sort the CU list (again, to ensure consistent output order).
-  std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) {
-    return A->getUniqueID() < B->getUniqueID();
-  });
+  std::sort(CUs.begin(), CUs.end(),
+            [](const DwarfCompileUnit *A, const DwarfCompileUnit *B) {
+              return A->getUniqueID() < B->getUniqueID();
+            });
 
   // Emit an arange table for each CU we used.
   for (DwarfCompileUnit *CU : CUs) {
@@ -1793,7 +1794,7 @@
 // DWARF5 Experimental Separate Dwarf emitters.
 
 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
-                                  std::unique_ptr<DwarfUnit> NewU) {
+                                  std::unique_ptr<DwarfCompileUnit> NewU) {
   NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
                   U.getCUNode()->getSplitDebugFilename());
 
@@ -1882,21 +1883,19 @@
   if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed())
     return;
 
-  const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy];
-  if (TU) {
-    CU.addDIETypeSignature(RefDie, *TU);
+  auto Ins = TypeSignatures.insert(std::make_pair(CTy, 0));
+  if (!Ins.second) {
+    CU.addDIETypeSignature(RefDie, Ins.first->second);
     return;
   }
 
   bool TopLevelType = TypeUnitsUnderConstruction.empty();
   AddrPool.resetUsedFlag();
 
-  auto OwnedUnit = make_unique<DwarfTypeUnit>(
-      InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
-      this, &InfoHolder, getDwoLineTable(CU));
+  auto OwnedUnit = make_unique<DwarfTypeUnit>(CU, Asm, this, &InfoHolder,
+                                              getDwoLineTable(CU));
   DwarfTypeUnit &NewTU = *OwnedUnit;
   DIE &UnitDie = NewTU.getUnitDie();
-  TU = &NewTU;
   TypeUnitsUnderConstruction.push_back(
       std::make_pair(std::move(OwnedUnit), CTy));
 
@@ -1905,6 +1904,7 @@
 
   uint64_t Signature = makeTypeSignature(Identifier);
   NewTU.setTypeSignature(Signature);
+  Ins.first->second = Signature;
 
   if (useSplitDwarf())
     NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
@@ -1928,7 +1928,7 @@
       // This is pessimistic as some of these types might not be dependent on
       // the type that used an address.
       for (const auto &TU : TypeUnitsToAdd)
-        DwarfTypeUnits.erase(TU.second);
+        TypeSignatures.erase(TU.second);
 
       // Construct this type in the CU directly.
       // This is inefficient because all the dependent types will be rebuilt
@@ -1940,10 +1940,12 @@
 
     // If the type wasn't dependent on fission addresses, finish adding the type
     // and all its dependent types.
-    for (auto &TU : TypeUnitsToAdd)
-      InfoHolder.addUnit(std::move(TU.first));
+    for (auto &TU : TypeUnitsToAdd) {
+      InfoHolder.computeSizeAndOffsetsForUnit(TU.first.get());
+      InfoHolder.emitUnit(TU.first.get(), useSplitDwarf());
+    }
   }
-  CU.addDIETypeSignature(RefDie, NewTU);
+  CU.addDIETypeSignature(RefDie, Signature);
 }
 
 // Accelerator table mutators - add each name along with its companion
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 720507a..31303e4 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -235,9 +235,9 @@
   /// Holders for the various debug information flags that we might need to
   /// have exposed. See accessor functions below for description.
 
-  /// Map from MDNodes for user-defined types to the type units that
-  /// describe them.
-  DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
+  /// Map from MDNodes for user-defined types to their type signatures. Also
+  /// used to keep track of which types we have emitted type units for.
+  DenseMap<const MDNode *, uint64_t> TypeSignatures;
 
   SmallVector<
       std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
@@ -295,7 +295,7 @@
 
   MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
 
-  const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
+  const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
     return InfoHolder.getUnits();
   }
 
@@ -391,7 +391,7 @@
 
   /// Initialize common features of skeleton units.
   void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
-                        std::unique_ptr<DwarfUnit> NewU);
+                        std::unique_ptr<DwarfCompileUnit> NewU);
 
   /// Construct the split debug info compile unit for the debug info
   /// section.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
index 51b27b4..e9fe98a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "DwarfFile.h"
+#include "DwarfCompileUnit.h"
 #include "DwarfDebug.h"
 #include "DwarfUnit.h"
 #include "llvm/ADT/STLExtras.h"
@@ -50,22 +51,25 @@
   return *New;
 }
 
-void DwarfFile::addUnit(std::unique_ptr<DwarfUnit> U) {
+void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
   CUs.push_back(std::move(U));
 }
 
 // Emit the various dwarf units to the unit section USection with
 // the abbreviations going into ASection.
 void DwarfFile::emitUnits(bool UseOffsets) {
-  for (const auto &TheU : CUs) {
-    DIE &Die = TheU->getUnitDie();
-    MCSection *USection = TheU->getSection();
-    Asm->OutStreamer->SwitchSection(USection);
+  for (const auto &TheU : CUs)
+    emitUnit(TheU.get(), UseOffsets);
+}
 
-    TheU->emitHeader(UseOffsets);
+void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
+  DIE &Die = TheU->getUnitDie();
+  MCSection *USection = TheU->getSection();
+  Asm->OutStreamer->SwitchSection(USection);
 
-    Asm->emitDwarfDIE(Die);
-  }
+  TheU->emitHeader(UseOffsets);
+
+  Asm->emitDwarfDIE(Die);
 }
 
 // Compute the size and offset for each DIE.
@@ -77,17 +81,20 @@
   // DIE within each compile unit. All offsets are CU relative.
   for (const auto &TheU : CUs) {
     TheU->setDebugInfoOffset(SecOffset);
-
-    // CU-relative offset is reset to 0 here.
-    unsigned Offset = sizeof(int32_t) +      // Length of Unit Info
-                      TheU->getHeaderSize(); // Unit-specific headers
-
-    // EndOffset here is CU-relative, after laying out
-    // all of the CU DIE.
-    unsigned EndOffset = computeSizeAndOffset(TheU->getUnitDie(), Offset);
-    SecOffset += EndOffset;
+    SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
   }
 }
+
+unsigned DwarfFile::computeSizeAndOffsetsForUnit(DwarfUnit *TheU) {
+  // CU-relative offset is reset to 0 here.
+  unsigned Offset = sizeof(int32_t) +      // Length of Unit Info
+                    TheU->getHeaderSize(); // Unit-specific headers
+
+  // The return value here is CU-relative, after laying out
+  // all of the CU DIE.
+  return computeSizeAndOffset(TheU->getUnitDie(), Offset);
+}
+
 // Compute the size and offset of a DIE. The offset is relative to start of the
 // CU. It returns the offset after laying out the DIE.
 unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
index 291319c..8b4e334 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.h
@@ -25,6 +25,7 @@
 namespace llvm {
 class AsmPrinter;
 class DbgVariable;
+class DwarfCompileUnit;
 class DwarfUnit;
 class DIEAbbrev;
 class MCSymbol;
@@ -47,7 +48,7 @@
   std::vector<DIEAbbrev *> Abbreviations;
 
   // A pointer to all units in the section.
-  SmallVector<std::unique_ptr<DwarfUnit>, 1> CUs;
+  SmallVector<std::unique_ptr<DwarfCompileUnit>, 1> CUs;
 
   DwarfStringPool StrPool;
 
@@ -67,7 +68,9 @@
 
   ~DwarfFile();
 
-  const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() { return CUs; }
+  const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
+    return CUs;
+  }
 
   /// \brief Compute the size and offset of a DIE given an incoming Offset.
   unsigned computeSizeAndOffset(DIE &Die, unsigned Offset);
@@ -75,6 +78,10 @@
   /// \brief Compute the size and offset of all the DIEs.
   void computeSizeAndOffsets();
 
+  /// \brief Compute the size and offset of all the DIEs in the given unit.
+  /// \returns The size of the root DIE.
+  unsigned computeSizeAndOffsetsForUnit(DwarfUnit *TheU);
+
   /// Define a unique number for the abbreviation.
   ///
   /// Compute the abbreviation for \c Die, look up its unique number, and
@@ -82,12 +89,15 @@
   DIEAbbrev &assignAbbrevNumber(DIE &Die);
 
   /// \brief Add a unit to the list of CUs.
-  void addUnit(std::unique_ptr<DwarfUnit> U);
+  void addUnit(std::unique_ptr<DwarfCompileUnit> U);
 
   /// \brief Emit all of the units to the section listed with the given
   /// abbreviation section.
   void emitUnits(bool UseOffsets);
 
+  /// \brief Emit the given unit to its section.
+  void emitUnit(DwarfUnit *U, bool UseOffsets);
+
   /// \brief Emit a set of abbreviations to the specific section.
   void emitAbbrevs(MCSection *);
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index d75fea5..d2cf8ef 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -63,21 +63,19 @@
   return MachineReg == TRI.getFrameRegister(*AP.MF);
 }
 
-DwarfUnit::DwarfUnit(unsigned UID, dwarf::Tag UnitTag,
-                     const DICompileUnit *Node, AsmPrinter *A, DwarfDebug *DW,
-                     DwarfFile *DWU)
-    : UniqueID(UID), CUNode(Node),
-      UnitDie(*DIE::get(DIEValueAllocator, UnitTag)), DebugInfoOffset(0),
-      Asm(A), DD(DW), DU(DWU), IndexTyDie(nullptr), Section(nullptr) {
+DwarfUnit::DwarfUnit(dwarf::Tag UnitTag, const DICompileUnit *Node,
+                     AsmPrinter *A, DwarfDebug *DW, DwarfFile *DWU)
+    : CUNode(Node), UnitDie(*DIE::get(DIEValueAllocator, UnitTag)), Asm(A),
+      DD(DW), DU(DWU), IndexTyDie(nullptr), Section(nullptr) {
   assert(UnitTag == dwarf::DW_TAG_compile_unit ||
          UnitTag == dwarf::DW_TAG_type_unit);
 }
 
-DwarfTypeUnit::DwarfTypeUnit(unsigned UID, DwarfCompileUnit &CU, AsmPrinter *A,
+DwarfTypeUnit::DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A,
                              DwarfDebug *DW, DwarfFile *DWU,
                              MCDwarfDwoLineTable *SplitLineTable)
-    : DwarfUnit(UID, dwarf::DW_TAG_type_unit, CU.getCUNode(), A, DW, DWU),
-      CU(CU), SplitLineTable(SplitLineTable) {
+    : DwarfUnit(dwarf::DW_TAG_type_unit, CU.getCUNode(), A, DW, DWU), CU(CU),
+      SplitLineTable(SplitLineTable) {
   if (SplitLineTable)
     addSectionOffset(UnitDie, dwarf::DW_AT_stmt_list, 0);
 }
@@ -268,7 +266,7 @@
   addDIEEntry(Die, Attribute, DIEEntry(Entry));
 }
 
-void DwarfUnit::addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type) {
+void DwarfUnit::addDIETypeSignature(DIE &Die, uint64_t Signature) {
   // Flag the type unit reference as a declaration so that if it contains
   // members (implicit special members, static data member definitions, member
   // declarations for definitions in this CU, etc) consumers don't get confused
@@ -276,7 +274,7 @@
   addFlag(Die, dwarf::DW_AT_declaration);
 
   Die.addValue(DIEValueAllocator, dwarf::DW_AT_signature,
-               dwarf::DW_FORM_ref_sig8, DIETypeSignature(Type));
+               dwarf::DW_FORM_ref_sig8, DIEInteger(Signature));
 }
 
 void DwarfUnit::addDIETypeSignature(DIE &Die, dwarf::Attribute Attribute,
@@ -1524,8 +1522,11 @@
   // start of the section. Use a relocatable offset where needed to ensure
   // linking doesn't invalidate that offset.
   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
-  Asm->emitDwarfSymbolReference(TLOF.getDwarfAbbrevSection()->getBeginSymbol(),
-                                UseOffsets);
+  if (UseOffsets)
+    Asm->EmitInt32(0);
+  else
+    Asm->emitDwarfSymbolReference(
+        TLOF.getDwarfAbbrevSection()->getBeginSymbol(), false);
 
   Asm->OutStreamer->AddComment("Address Size (in bytes)");
   Asm->EmitInt8(Asm->getDataLayout().getPointerSize());
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 82760bf..a79add6 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -67,9 +67,6 @@
 /// source file.
 class DwarfUnit {
 protected:
-  /// A numeric ID unique among all CUs in the module
-  unsigned UniqueID;
-
   /// MDNode for the compile unit.
   const DICompileUnit *CUNode;
 
@@ -79,9 +76,6 @@
   /// Unit debug information entry.
   DIE &UnitDie;
 
-  /// Offset of the UnitDie from beginning of debug info section.
-  unsigned DebugInfoOffset;
-
   /// Target of Dwarf emission.
   AsmPrinter *Asm;
 
@@ -110,8 +104,8 @@
   /// The section this unit will be emitted in.
   MCSection *Section;
 
-  DwarfUnit(unsigned UID, dwarf::Tag, const DICompileUnit *CU, AsmPrinter *A,
-            DwarfDebug *DW, DwarfFile *DWU);
+  DwarfUnit(dwarf::Tag, const DICompileUnit *CU, AsmPrinter *A, DwarfDebug *DW,
+            DwarfFile *DWU);
 
   bool applySubprogramDefinitionAttributes(const DISubprogram *SP, DIE &SPDie);
 
@@ -127,14 +121,10 @@
 
   // Accessors.
   AsmPrinter* getAsmPrinter() const { return Asm; }
-  unsigned getUniqueID() const { return UniqueID; }
   uint16_t getLanguage() const { return CUNode->getSourceLanguage(); }
   const DICompileUnit *getCUNode() const { return CUNode; }
   DIE &getUnitDie() { return UnitDie; }
 
-  unsigned getDebugInfoOffset() const { return DebugInfoOffset; }
-  void setDebugInfoOffset(unsigned DbgInfoOff) { DebugInfoOffset = DbgInfoOff; }
-
   /// Return true if this compile unit has something to write out.
   bool hasContent() const { return UnitDie.hasChildren(); }
 
@@ -221,7 +211,7 @@
   void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
 
   /// Add a type's DW_AT_signature and set the  declaration flag.
-  void addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type);
+  void addDIETypeSignature(DIE &Die, uint64_t Signature);
   /// Add an attribute containing the type signature for a unique identifier.
   void addDIETypeSignature(DIE &Die, dwarf::Attribute Attribute,
                            StringRef Identifier);
@@ -383,12 +373,10 @@
   bool isDwoUnit() const override;
 
 public:
-  DwarfTypeUnit(unsigned UID, DwarfCompileUnit &CU, AsmPrinter *A,
-                DwarfDebug *DW, DwarfFile *DWU,
-                MCDwarfDwoLineTable *SplitLineTable = nullptr);
+  DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A, DwarfDebug *DW,
+                DwarfFile *DWU, MCDwarfDwoLineTable *SplitLineTable = nullptr);
 
   void setTypeSignature(uint64_t Signature) { TypeSignature = Signature; }
-  uint64_t getTypeSignature() const { return TypeSignature; }
   void setType(const DIE *Ty) { this->Ty = Ty; }
 
   /// Emit the header for this unit, not including the initial length field.