Revert "AsmPrinter: Change DIEValue to be stored by value"

This reverts commit r238349, since it caused some errors on bots:
  - std::is_trivially_copyable isn't available until GCC 5.0.
  - It was complaining about strict aliasing with my use of
    ArrayCharUnion.

llvm-svn: 238350

9 files changed, 178 insertions, 118 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
index 42e7cf7f35c..3258961bfb1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp
@@ -265,7 +265,7 @@ void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
                             dwarf::TagString(Abbrev.getTag()));
   EmitULEB128(Abbrev.getNumber());
 
-  const SmallVectorImpl<DIEValue> &Values = Die.getValues();
+  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
   const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
 
   // Emit the DIE attribute values.
@@ -277,12 +277,12 @@ void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
     if (isVerbose()) {
       OutStreamer->AddComment(dwarf::AttributeString(Attr));
       if (Attr == dwarf::DW_AT_accessibility)
-        OutStreamer->AddComment(
-            dwarf::AccessibilityString(Values[i].getDIEInteger().getValue()));
+        OutStreamer->AddComment(dwarf::AccessibilityString(
+            cast<DIEInteger>(Values[i])->getValue()));
     }
 
     // Emit an attribute using the defined form.
-    Values[i].EmitValue(this, Form);
+    Values[i]->EmitValue(this, Form);
   }
 
   // Emit the DIE children if any.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
index a3c79d938b6..1ccffe97b80 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -128,8 +128,8 @@ const DIE *DIE::getUnitOrNull() const {
   return nullptr;
 }
 
-DIEValue DIE::findAttribute(dwarf::Attribute Attribute) const {
-  const SmallVectorImpl<DIEValue> &Values = getValues();
+DIEValue *DIE::findAttribute(dwarf::Attribute Attribute) const {
+  const SmallVectorImpl<DIEValue *> &Values = getValues();
   const DIEAbbrev &Abbrevs = getAbbrev();
 
   // Iterate through all the attributes until we find the one we're
@@ -137,7 +137,7 @@ DIEValue DIE::findAttribute(dwarf::Attribute Attribute) const {
   for (size_t i = 0; i < Values.size(); ++i)
     if (Abbrevs.getData()[i].getAttribute() == Attribute)
       return Values[i];
-  return DIEValue();
+  return nullptr;
 }
 
 #ifndef NDEBUG
@@ -174,7 +174,7 @@ void DIE::print(raw_ostream &O, unsigned IndentCount) const {
     O <<  "  "
       << dwarf::FormEncodingString(Data[i].getForm())
       << " ";
-    Values[i].print(O);
+    Values[i]->print(O);
     O << "\n";
   }
   IndentCount -= 2;
@@ -193,11 +193,9 @@ void DIE::dump() {
 
 void DIEValue::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
   switch (Ty) {
-  case isNone:
-    llvm_unreachable("Expected valid DIEValue");
 #define EMIT_VALUE_IMPL(Kind)                                                  \
   case is##Kind:                                                               \
-    getDIE##Kind().EmitValue(AP, Form);                                        \
+    cast<DIE##Kind>(this)->EmitValueImpl(AP, Form);                            \
     break;
     EMIT_VALUE_IMPL(Integer)
     EMIT_VALUE_IMPL(String)
@@ -215,11 +213,9 @@ void DIEValue::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
 
 unsigned DIEValue::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
   switch (Ty) {
-  case isNone:
-    llvm_unreachable("Expected valid DIEValue");
 #define SIZE_OF_IMPL(Kind)                                                     \
   case is##Kind:                                                               \
-    return getDIE##Kind().SizeOf(AP, Form);
+    return cast<DIE##Kind>(this)->SizeOfImpl(AP, Form);
     SIZE_OF_IMPL(Integer)
     SIZE_OF_IMPL(String)
     SIZE_OF_IMPL(Expr)
@@ -238,11 +234,9 @@ unsigned DIEValue::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 #ifndef NDEBUG
 void DIEValue::print(raw_ostream &O) const {
   switch (Ty) {
-  case isNone:
-    llvm_unreachable("Expected valid DIEValue");
 #define PRINT_IMPL(Kind)                                                       \
   case is##Kind:                                                               \
-    getDIE##Kind().print(O);                                                   \
+    cast<DIE##Kind>(this)->printImpl(O);                                       \
     break;
     PRINT_IMPL(Integer)
     PRINT_IMPL(String)
@@ -269,7 +263,7 @@ void DIEValue::dump() const {
 
 /// EmitValue - Emit integer of appropriate size.
 ///
-void DIEInteger::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
+void DIEInteger::EmitValueImpl(const AsmPrinter *Asm, dwarf::Form Form) const {
   unsigned Size = ~0U;
   switch (Form) {
   case dwarf::DW_FORM_flag_present:
@@ -305,7 +299,7 @@ void DIEInteger::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
 
 /// SizeOf - Determine size of integer value in bytes.
 ///
-unsigned DIEInteger::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIEInteger::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   switch (Form) {
   case dwarf::DW_FORM_flag_present: return 0;
   case dwarf::DW_FORM_flag:  // Fall thru
@@ -334,7 +328,7 @@ unsigned DIEInteger::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIEInteger::print(raw_ostream &O) const {
+void DIEInteger::printImpl(raw_ostream &O) const {
   O << "Int: " << (int64_t)Integer << "  0x";
   O.write_hex(Integer);
 }
@@ -346,13 +340,13 @@ void DIEInteger::print(raw_ostream &O) const {
 
 /// EmitValue - Emit expression value.
 ///
-void DIEExpr::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIEExpr::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   AP->OutStreamer->EmitValue(Expr, SizeOf(AP, Form));
 }
 
 /// SizeOf - Determine size of expression value in bytes.
 ///
-unsigned DIEExpr::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIEExpr::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   if (Form == dwarf::DW_FORM_data4) return 4;
   if (Form == dwarf::DW_FORM_sec_offset) return 4;
   if (Form == dwarf::DW_FORM_strp) return 4;
@@ -360,7 +354,7 @@ unsigned DIEExpr::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIEExpr::print(raw_ostream &O) const { O << "Expr: " << *Expr; }
+void DIEExpr::printImpl(raw_ostream &O) const { O << "Expr: " << *Expr; }
 #endif
 
 //===----------------------------------------------------------------------===//
@@ -369,7 +363,7 @@ void DIEExpr::print(raw_ostream &O) const { O << "Expr: " << *Expr; }
 
 /// EmitValue - Emit label value.
 ///
-void DIELabel::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIELabel::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   AP->EmitLabelReference(Label, SizeOf(AP, Form),
                          Form == dwarf::DW_FORM_strp ||
                              Form == dwarf::DW_FORM_sec_offset ||
@@ -378,7 +372,7 @@ void DIELabel::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
 
 /// SizeOf - Determine size of label value in bytes.
 ///
-unsigned DIELabel::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIELabel::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   if (Form == dwarf::DW_FORM_data4) return 4;
   if (Form == dwarf::DW_FORM_sec_offset) return 4;
   if (Form == dwarf::DW_FORM_strp) return 4;
@@ -386,7 +380,9 @@ unsigned DIELabel::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIELabel::print(raw_ostream &O) const { O << "Lbl: " << Label->getName(); }
+void DIELabel::printImpl(raw_ostream &O) const {
+  O << "Lbl: " << Label->getName();
+}
 #endif
 
 //===----------------------------------------------------------------------===//
@@ -395,13 +391,13 @@ void DIELabel::print(raw_ostream &O) const { O << "Lbl: " << Label->getName(); }
 
 /// EmitValue - Emit delta value.
 ///
-void DIEDelta::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIEDelta::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   AP->EmitLabelDifference(LabelHi, LabelLo, SizeOf(AP, Form));
 }
 
 /// SizeOf - Determine size of delta value in bytes.
 ///
-unsigned DIEDelta::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIEDelta::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   if (Form == dwarf::DW_FORM_data4) return 4;
   if (Form == dwarf::DW_FORM_sec_offset) return 4;
   if (Form == dwarf::DW_FORM_strp) return 4;
@@ -409,7 +405,7 @@ unsigned DIEDelta::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIEDelta::print(raw_ostream &O) const {
+void DIEDelta::printImpl(raw_ostream &O) const {
   O << "Del: " << LabelHi->getName() << "-" << LabelLo->getName();
 }
 #endif
@@ -420,7 +416,7 @@ void DIEDelta::print(raw_ostream &O) const {
 
 /// EmitValue - Emit string value.
 ///
-void DIEString::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIEString::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   assert(
       (Form == dwarf::DW_FORM_strp || Form == dwarf::DW_FORM_GNU_str_index) &&
       "Expected valid string form");
@@ -444,7 +440,7 @@ void DIEString::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
 
 /// SizeOf - Determine size of delta value in bytes.
 ///
-unsigned DIEString::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIEString::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   assert(
       (Form == dwarf::DW_FORM_strp || Form == dwarf::DW_FORM_GNU_str_index) &&
       "Expected valid string form");
@@ -462,7 +458,7 @@ unsigned DIEString::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIEString::print(raw_ostream &O) const {
+void DIEString::printImpl(raw_ostream &O) const {
   O << "String: " << S.getString();
 }
 #endif
@@ -473,16 +469,16 @@ void DIEString::print(raw_ostream &O) const {
 
 /// EmitValue - Emit debug information entry offset.
 ///
-void DIEEntry::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIEEntry::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
 
   if (Form == dwarf::DW_FORM_ref_addr) {
     const DwarfDebug *DD = AP->getDwarfDebug();
-    unsigned Addr = Entry->getOffset();
+    unsigned Addr = Entry.getOffset();
     assert(!DD->useSplitDwarf() && "TODO: dwo files can't have relocations.");
     // For DW_FORM_ref_addr, output the offset from beginning of debug info
     // section. Entry->getOffset() returns the offset from start of the
     // compile unit.
-    DwarfCompileUnit *CU = DD->lookupUnit(Entry->getUnit());
+    DwarfCompileUnit *CU = DD->lookupUnit(Entry.getUnit());
     assert(CU && "CUDie should belong to a CU.");
     Addr += CU->getDebugInfoOffset();
     if (AP->MAI->doesDwarfUseRelocationsAcrossSections())
@@ -491,7 +487,7 @@ void DIEEntry::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
     else
       AP->OutStreamer->EmitIntValue(Addr, DIEEntry::getRefAddrSize(AP));
   } else
-    AP->EmitInt32(Entry->getOffset());
+    AP->EmitInt32(Entry.getOffset());
 }
 
 unsigned DIEEntry::getRefAddrSize(const AsmPrinter *AP) {
@@ -507,7 +503,7 @@ unsigned DIEEntry::getRefAddrSize(const AsmPrinter *AP) {
 }
 
 #ifndef NDEBUG
-void DIEEntry::print(raw_ostream &O) const {
+void DIEEntry::printImpl(raw_ostream &O) const {
   O << format("Die: 0x%lx", (long)(intptr_t)&Entry);
 }
 #endif
@@ -515,15 +511,14 @@ void DIEEntry::print(raw_ostream &O) const {
 //===----------------------------------------------------------------------===//
 // DIETypeSignature Implementation
 //===----------------------------------------------------------------------===//
-void DIETypeSignature::EmitValue(const AsmPrinter *Asm,
-                                 dwarf::Form Form) const {
+void DIETypeSignature::EmitValueImpl(const AsmPrinter *Asm, dwarf::Form Form) const {
   assert(Form == dwarf::DW_FORM_ref_sig8);
-  Asm->OutStreamer->EmitIntValue(Unit->getTypeSignature(), 8);
+  Asm->OutStreamer->EmitIntValue(Unit.getTypeSignature(), 8);
 }
 
 #ifndef NDEBUG
-void DIETypeSignature::print(raw_ostream &O) const {
-  O << format("Type Unit: 0x%lx", Unit->getTypeSignature());
+void DIETypeSignature::printImpl(raw_ostream &O) const {
+  O << format("Type Unit: 0x%lx", Unit.getTypeSignature());
 }
 #endif
 
@@ -537,7 +532,7 @@ unsigned DIELoc::ComputeSize(const AsmPrinter *AP) const {
   if (!Size) {
     const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
     for (unsigned i = 0, N = Values.size(); i < N; ++i)
-      Size += Values[i].SizeOf(AP, AbbrevData[i].getForm());
+      Size += Values[i]->SizeOf(AP, AbbrevData[i].getForm());
   }
 
   return Size;
@@ -545,7 +540,7 @@ unsigned DIELoc::ComputeSize(const AsmPrinter *AP) const {
 
 /// EmitValue - Emit location data.
 ///
-void DIELoc::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
+void DIELoc::EmitValueImpl(const AsmPrinter *Asm, dwarf::Form Form) const {
   switch (Form) {
   default: llvm_unreachable("Improper form for block");
   case dwarf::DW_FORM_block1: Asm->EmitInt8(Size);    break;
@@ -558,12 +553,12 @@ void DIELoc::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
 
   const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
   for (unsigned i = 0, N = Values.size(); i < N; ++i)
-    Values[i].EmitValue(Asm, AbbrevData[i].getForm());
+    Values[i]->EmitValue(Asm, AbbrevData[i].getForm());
 }
 
 /// SizeOf - Determine size of location data in bytes.
 ///
-unsigned DIELoc::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIELoc::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   switch (Form) {
   case dwarf::DW_FORM_block1: return Size + sizeof(int8_t);
   case dwarf::DW_FORM_block2: return Size + sizeof(int16_t);
@@ -576,7 +571,7 @@ unsigned DIELoc::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIELoc::print(raw_ostream &O) const {
+void DIELoc::printImpl(raw_ostream &O) const {
   O << "ExprLoc: ";
   DIE::print(O, 5);
 }
@@ -592,7 +587,7 @@ unsigned DIEBlock::ComputeSize(const AsmPrinter *AP) const {
   if (!Size) {
     const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
     for (unsigned i = 0, N = Values.size(); i < N; ++i)
-      Size += Values[i].SizeOf(AP, AbbrevData[i].getForm());
+      Size += Values[i]->SizeOf(AP, AbbrevData[i].getForm());
   }
 
   return Size;
@@ -600,7 +595,7 @@ unsigned DIEBlock::ComputeSize(const AsmPrinter *AP) const {
 
 /// EmitValue - Emit block data.
 ///
-void DIEBlock::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
+void DIEBlock::EmitValueImpl(const AsmPrinter *Asm, dwarf::Form Form) const {
   switch (Form) {
   default: llvm_unreachable("Improper form for block");
   case dwarf::DW_FORM_block1: Asm->EmitInt8(Size);    break;
@@ -611,12 +606,12 @@ void DIEBlock::EmitValue(const AsmPrinter *Asm, dwarf::Form Form) const {
 
   const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
   for (unsigned i = 0, N = Values.size(); i < N; ++i)
-    Values[i].EmitValue(Asm, AbbrevData[i].getForm());
+    Values[i]->EmitValue(Asm, AbbrevData[i].getForm());
 }
 
 /// SizeOf - Determine size of block data in bytes.
 ///
-unsigned DIEBlock::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIEBlock::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   switch (Form) {
   case dwarf::DW_FORM_block1: return Size + sizeof(int8_t);
   case dwarf::DW_FORM_block2: return Size + sizeof(int16_t);
@@ -627,7 +622,7 @@ unsigned DIEBlock::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIEBlock::print(raw_ostream &O) const {
+void DIEBlock::printImpl(raw_ostream &O) const {
   O << "Blk: ";
   DIE::print(O, 5);
 }
@@ -637,7 +632,7 @@ void DIEBlock::print(raw_ostream &O) const {
 // DIELocList Implementation
 //===----------------------------------------------------------------------===//
 
-unsigned DIELocList::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
+unsigned DIELocList::SizeOfImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   if (Form == dwarf::DW_FORM_data4)
     return 4;
   if (Form == dwarf::DW_FORM_sec_offset)
@@ -647,7 +642,7 @@ unsigned DIELocList::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
 
 /// EmitValue - Emit label value.
 ///
-void DIELocList::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
+void DIELocList::EmitValueImpl(const AsmPrinter *AP, dwarf::Form Form) const {
   DwarfDebug *DD = AP->getDwarfDebug();
   MCSymbol *Label = DD->getDebugLocs().getList(Index).Label;
 
@@ -658,5 +653,8 @@ void DIELocList::EmitValue(const AsmPrinter *AP, dwarf::Form Form) const {
 }
 
 #ifndef NDEBUG
-void DIELocList::print(raw_ostream &O) const { O << "LocList: " << Index; }
+void DIELocList::printImpl(raw_ostream &O) const {
+  O << "LocList: " << Index;
+
+}
 #endif
diff --git a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
index 53e02fac6e3..a2e5aad9657 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DIEHash.cpp
@@ -31,14 +31,18 @@ using namespace llvm;
 /// \brief Grabs the string in whichever attribute is passed in and returns
 /// a reference to it.
 static StringRef getDIEStringAttr(const DIE &Die, uint16_t Attr) {
-  const auto &Values = Die.getValues();
+  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
   const DIEAbbrev &Abbrevs = Die.getAbbrev();
 
   // Iterate through all the attributes until we find the one we're
   // looking for, if we can't find it return an empty string.
   for (size_t i = 0; i < Values.size(); ++i) {
-    if (Abbrevs.getData()[i].getAttribute() == Attr)
-      return Values[i].getDIEString().getString();
+    if (Abbrevs.getData()[i].getAttribute() == Attr) {
+      DIEValue *V = Values[i];
+      assert(isa<DIEString>(V) && "String requested. Not a string.");
+      DIEString *S = cast<DIEString>(V);
+      return S->getString();
+    }
   }
   return StringRef("");
 }
@@ -119,7 +123,7 @@ void DIEHash::addParentContext(const DIE &Parent) {
 
 // Collect all of the attributes for a particular DIE in single structure.
 void DIEHash::collectAttributes(const DIE &Die, DIEAttrs &Attrs) {
-  const SmallVectorImpl<DIEValue> &Values = Die.getValues();
+  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
   const DIEAbbrev &Abbrevs = Die.getAbbrev();
 
 #define COLLECT_ATTR(NAME)                                                     \
@@ -270,9 +274,11 @@ void DIEHash::hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag,
 
 // Hash all of the values in a block like set of values. This assumes that
 // all of the data is going to be added as integers.
-void DIEHash::hashBlockData(const SmallVectorImpl<DIEValue> &Values) {
-  for (auto I = Values.begin(), E = Values.end(); I != E; ++I)
-    Hash.update((uint64_t)I->getDIEInteger().getValue());
+void DIEHash::hashBlockData(const SmallVectorImpl<DIEValue *> &Values) {
+  for (SmallVectorImpl<DIEValue *>::const_iterator I = Values.begin(),
+                                                   E = Values.end();
+       I != E; ++I)
+    Hash.update((uint64_t)cast<DIEInteger>(*I)->getValue());
 }
 
 // Hash the contents of a loclistptr class.
@@ -287,7 +293,7 @@ void DIEHash::hashLocList(const DIELocList &LocList) {
 // Hash an individual attribute \param Attr based on the type of attribute and
 // the form.
 void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
-  const DIEValue &Value = Attr.Val;
+  const DIEValue *Value = Attr.Val;
   const DIEAbbrevData *Desc = Attr.Desc;
   dwarf::Attribute Attribute = Desc->getAttribute();
 
@@ -298,15 +304,12 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
   // computation is limited to the following: DW_FORM_sdata, DW_FORM_flag,
   // DW_FORM_string, and DW_FORM_block.
 
-  switch (Value.getType()) {
-  case DIEValue::isNone:
-    llvm_unreachable("Expected valid DIEValue");
-
+  switch (Value->getType()) {
     // 7.27 Step 3
     // ... An attribute that refers to another type entry T is processed as
     // follows:
   case DIEValue::isEntry:
-    hashDIEEntry(Attribute, Tag, Value.getDIEEntry().getEntry());
+    hashDIEEntry(Attribute, Tag, cast<DIEEntry>(Value)->getEntry());
     break;
   case DIEValue::isInteger: {
     addULEB128('A');
@@ -319,14 +322,14 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
     case dwarf::DW_FORM_udata:
     case dwarf::DW_FORM_sdata:
       addULEB128(dwarf::DW_FORM_sdata);
-      addSLEB128((int64_t)Value.getDIEInteger().getValue());
+      addSLEB128((int64_t)cast<DIEInteger>(Value)->getValue());
       break;
     // DW_FORM_flag_present is just flag with a value of one. We still give it a
     // value so just use the value.
     case dwarf::DW_FORM_flag_present:
     case dwarf::DW_FORM_flag:
       addULEB128(dwarf::DW_FORM_flag);
-      addULEB128((int64_t)Value.getDIEInteger().getValue());
+      addULEB128((int64_t)cast<DIEInteger>(Value)->getValue());
       break;
     default:
       llvm_unreachable("Unknown integer form!");
@@ -337,7 +340,7 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
     addULEB128('A');
     addULEB128(Attribute);
     addULEB128(dwarf::DW_FORM_string);
-    addString(Value.getDIEString().getString());
+    addString(cast<DIEString>(Value)->getString());
     break;
   case DIEValue::isBlock:
   case DIEValue::isLoc:
@@ -345,17 +348,17 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
     addULEB128('A');
     addULEB128(Attribute);
     addULEB128(dwarf::DW_FORM_block);
-    if (Value.getType() == DIEValue::isBlock) {
-      addULEB128(Value.getDIEBlock().ComputeSize(AP));
-      hashBlockData(Value.getDIEBlock().getValues());
-    } else if (Value.getType() == DIEValue::isLoc) {
-      addULEB128(Value.getDIELoc().ComputeSize(AP));
-      hashBlockData(Value.getDIELoc().getValues());
+    if (isa<DIEBlock>(Value)) {
+      addULEB128(cast<DIEBlock>(Value)->ComputeSize(AP));
+      hashBlockData(cast<DIEBlock>(Value)->getValues());
+    } else if (isa<DIELoc>(Value)) {
+      addULEB128(cast<DIELoc>(Value)->ComputeSize(AP));
+      hashBlockData(cast<DIELoc>(Value)->getValues());
     } else {
       // We could add the block length, but that would take
       // a bit of work and not add a lot of uniqueness
       // to the hash in some way we could test.
-      hashLocList(Value.getDIELocList());
+      hashLocList(*cast<DIELocList>(Value));
     }
     break;
     // FIXME: It's uncertain whether or not we should handle this at the moment.
@@ -372,7 +375,7 @@ void DIEHash::hashAttribute(AttrEntry Attr, dwarf::Tag Tag) {
 void DIEHash::hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag) {
 #define ADD_ATTR(ATTR)                                                         \
   {                                                                            \
-    if (ATTR.Val)                                                              \
+    if (ATTR.Val != 0)                                                         \
       hashAttribute(ATTR, Tag);                                                \
   }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DIEHash.h b/llvm/lib/CodeGen/AsmPrinter/DIEHash.h
index f71fac21064..ac014b727b7 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DIEHash.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DIEHash.h
@@ -29,7 +29,7 @@ class DIEHash {
 
   // The entry for a particular attribute.
   struct AttrEntry {
-    DIEValue Val;
+    const DIEValue *Val;
     const DIEAbbrevData *Desc;
   };
 
@@ -135,7 +135,7 @@ private:
 
   /// \brief Hashes the data in a block like DIEValue, e.g. DW_FORM_block or
   /// DW_FORM_exprloc.
-  void hashBlockData(const SmallVectorImpl<DIEValue> &Values);
+  void hashBlockData(const SmallVectorImpl<DIEValue *> &Values);
 
   /// \brief Hashes the contents pointed to in the .debug_loc section.
   void hashLocList(const DIELocList &LocList);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 2256200c8d0..c10e70352af 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -42,7 +42,8 @@ void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
     DD->addArangeLabel(SymbolCU(this, Label));
 
   unsigned idx = DD->getAddressPool().getIndex(Label);
-  Die.addValue(Attribute, dwarf::DW_FORM_GNU_addr_index, DIEInteger(idx));
+  DIEValue *Value = new (DIEValueAllocator) DIEInteger(idx);
+  Die.addValue(Attribute, dwarf::DW_FORM_GNU_addr_index, Value);
 }
 
 void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
@@ -52,7 +53,8 @@ void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
     DD->addArangeLabel(SymbolCU(this, Label));
 
   Die.addValue(Attribute, dwarf::DW_FORM_addr,
-               Label ? DIEValue(DIELabel(Label)) : DIEValue(DIEInteger(0)));
+               Label ? (DIEValue *)new (DIEValueAllocator) DIELabel(Label)
+                     : new (DIEValueAllocator) DIEInteger(0));
 }
 
 unsigned DwarfCompileUnit::getOrCreateSourceID(StringRef FileName,
@@ -143,7 +145,7 @@ DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
   bool addToAccelTable = false;
   if (auto *Global = dyn_cast_or_null<GlobalVariable>(GV->getVariable())) {
     addToAccelTable = true;
-    DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
     const MCSymbol *Sym = Asm->getSymbol(Global);
     if (Global->isThreadLocal()) {
       // FIXME: Make this work with -gsplit-dwarf.
@@ -181,7 +183,7 @@ DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
   } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV->getVariable())) {
     addToAccelTable = true;
     // GV is a merged global.
-    DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
     Value *Ptr = CE->getOperand(0);
     MCSymbol *Sym = Asm->getSymbol(cast<GlobalValue>(Ptr));
     DD->addArangeLabel(SymbolCU(this, Sym));
@@ -363,9 +365,10 @@ void DwarfCompileUnit::constructScopeDIE(
 
 void DwarfCompileUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
                                        const MCSymbol *Hi, const MCSymbol *Lo) {
+  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
   Die.addValue(Attribute, DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
                                                      : dwarf::DW_FORM_data4,
-               new (DIEValueAllocator) DIEDelta(Hi, Lo));
+               Value);
 }
 
 void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
@@ -512,7 +515,7 @@ DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
     return VariableDie;
 
   auto Expr = DV.getExpression().begin();
-  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
   for (auto FI : DV.getFrameIndex()) {
     unsigned FrameReg = 0;
@@ -736,7 +739,7 @@ void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
 /// Add an address attribute to a die based on the location provided.
 void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
                                   const MachineLocation &Location) {
-  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
 
   bool validReg;
   if (Location.isReg())
@@ -758,7 +761,7 @@ void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
 void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
                                          dwarf::Attribute Attribute,
                                          const MachineLocation &Location) {
-  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
   assert(DV.getExpression().size() == 1);
   const DIExpression *Expr = DV.getExpression().back();
@@ -779,9 +782,10 @@ void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
 /// Add a Dwarf loclistptr attribute data and value.
 void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
                                        unsigned Index) {
+  DIEValue *Value = new (DIEValueAllocator) DIELocList(Index);
   dwarf::Form Form = DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
                                                 : dwarf::DW_FORM_data4;
-  Die.addValue(Attribute, Form, DIELocList(Index));
+  Die.addValue(Attribute, Form, Value);
 }
 
 void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
@@ -798,7 +802,8 @@ void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
 /// Add a Dwarf expression attribute data and value.
 void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
                                const MCExpr *Expr) {
-  Die.addValue((dwarf::Attribute)0, Form, DIEExpr(Expr));
+  DIEValue *Value = new (DIEValueAllocator) DIEExpr(Expr);
+  Die.addValue((dwarf::Attribute)0, Form, Value);
 }
 
 void DwarfCompileUnit::applySubprogramAttributesToDefinition(
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index e891ab9896b..105ff6c198f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1340,8 +1340,9 @@ static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU,
 
   // We could have a specification DIE that has our most of our knowledge,
   // look for that now.
-  if (DIEValue SpecVal = Die->findAttribute(dwarf::DW_AT_specification)) {
-    DIE &SpecDIE = SpecVal.getDIEEntry().getEntry();
+  DIEValue *SpecVal = Die->findAttribute(dwarf::DW_AT_specification);
+  if (SpecVal) {
+    DIE &SpecDIE = cast<DIEEntry>(SpecVal)->getEntry();
     if (SpecDIE.findAttribute(dwarf::DW_AT_external))
       Linkage = dwarf::GIEL_EXTERNAL;
   } else if (Die->findAttribute(dwarf::DW_AT_external))
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
index 9951c1d116d..10b58d4e86a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
@@ -94,13 +94,13 @@ unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
   // Start the size with the size of abbreviation code.
   Offset += getULEB128Size(Die.getAbbrevNumber());
 
-  const SmallVectorImpl<DIEValue> &Values = Die.getValues();
+  const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
   const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
 
   // Size the DIE attribute values.
   for (unsigned i = 0, N = Values.size(); i < N; ++i)
     // Size attribute value.
-    Offset += Values[i].SizeOf(Asm, AbbrevData[i].getForm());
+    Offset += Values[i]->SizeOf(Asm, AbbrevData[i].getForm());
 
   // Get the children.
   const auto &Children = Die.getChildren();
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index fc57f261188..04836c61404 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -70,6 +70,7 @@ DwarfUnit::DwarfUnit(unsigned UID, dwarf::Tag UnitTag,
       DD(DW), DU(DWU), IndexTyDie(nullptr), Section(nullptr) {
   assert(UnitTag == dwarf::DW_TAG_compile_unit ||
          UnitTag == dwarf::DW_TAG_type_unit);
+  DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1);
 }
 
 DwarfTypeUnit::DwarfTypeUnit(unsigned UID, DwarfCompileUnit &CU, AsmPrinter *A,
@@ -88,6 +89,11 @@ DwarfUnit::~DwarfUnit() {
     DIELocs[j]->~DIELoc();
 }
 
+DIEEntry *DwarfUnit::createDIEEntry(DIE &Entry) {
+  DIEEntry *Value = new (DIEValueAllocator) DIEEntry(Entry);
+  return Value;
+}
+
 int64_t DwarfUnit::getDefaultLowerBound() const {
   switch (getLanguage()) {
   default:
@@ -184,16 +190,18 @@ void DwarfUnit::insertDIE(const DINode *Desc, DIE *D) {
 
 void DwarfUnit::addFlag(DIE &Die, dwarf::Attribute Attribute) {
   if (DD->getDwarfVersion() >= 4)
-    Die.addValue(Attribute, dwarf::DW_FORM_flag_present, DIEInteger(1));
+    Die.addValue(Attribute, dwarf::DW_FORM_flag_present, DIEIntegerOne);
   else
-    Die.addValue(Attribute, dwarf::DW_FORM_flag, DIEInteger(1));
+    Die.addValue(Attribute, dwarf::DW_FORM_flag, DIEIntegerOne);
 }
 
 void DwarfUnit::addUInt(DIE &Die, dwarf::Attribute Attribute,
                         Optional<dwarf::Form> Form, uint64_t Integer) {
   if (!Form)
     Form = DIEInteger::BestForm(false, Integer);
-  Die.addValue(Attribute, *Form, DIEInteger(Integer));
+  DIEValue *Value = Integer == 1 ? DIEIntegerOne : new (DIEValueAllocator)
+                        DIEInteger(Integer);
+  Die.addValue(Attribute, *Form, Value);
 }
 
 void DwarfUnit::addUInt(DIE &Block, dwarf::Form Form, uint64_t Integer) {
@@ -204,7 +212,8 @@ void DwarfUnit::addSInt(DIE &Die, dwarf::Attribute Attribute,
                         Optional<dwarf::Form> Form, int64_t Integer) {
   if (!Form)
     Form = DIEInteger::BestForm(true, Integer);
-  Die.addValue(Attribute, *Form, DIEInteger(Integer));
+  DIEValue *Value = new (DIEValueAllocator) DIEInteger(Integer);
+  Die.addValue(Attribute, *Form, Value);
 }
 
 void DwarfUnit::addSInt(DIELoc &Die, Optional<dwarf::Form> Form,
@@ -216,12 +225,14 @@ void DwarfUnit::addString(DIE &Die, dwarf::Attribute Attribute,
                           StringRef String) {
   Die.addValue(Attribute,
                isDwoUnit() ? dwarf::DW_FORM_GNU_str_index : dwarf::DW_FORM_strp,
+               new (DIEValueAllocator)
                DIEString(DU->getStringPool().getEntry(*Asm, String)));
 }
 
 void DwarfUnit::addLabel(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form,
                          const MCSymbol *Label) {
-  Die.addValue(Attribute, Form, DIELabel(Label));
+  DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
+  Die.addValue(Attribute, Form, Value);
 }
 
 void DwarfUnit::addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label) {
@@ -254,12 +265,12 @@ void DwarfUnit::addOpAddress(DIELoc &Die, const MCSymbol *Sym) {
 
 void DwarfUnit::addLabelDelta(DIE &Die, dwarf::Attribute Attribute,
                               const MCSymbol *Hi, const MCSymbol *Lo) {
-  Die.addValue(Attribute, dwarf::DW_FORM_data4,
-               new (DIEValueAllocator) DIEDelta(Hi, Lo));
+  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
+  Die.addValue(Attribute, dwarf::DW_FORM_data4, Value);
 }
 
 void DwarfUnit::addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry) {
-  addDIEEntry(Die, Attribute, DIEEntry(Entry));
+  addDIEEntry(Die, Attribute, createDIEEntry(Entry));
 }
 
 void DwarfUnit::addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type) {
@@ -270,13 +281,13 @@ void DwarfUnit::addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type) {
   addFlag(Die, dwarf::DW_AT_declaration);
 
   Die.addValue(dwarf::DW_AT_signature, dwarf::DW_FORM_ref_sig8,
-               DIETypeSignature(Type));
+               new (DIEValueAllocator) DIETypeSignature(Type));
 }
 
 void DwarfUnit::addDIEEntry(DIE &Die, dwarf::Attribute Attribute,
-                            DIEEntry Entry) {
+                            DIEEntry *Entry) {
   const DIE *DieCU = Die.getUnitOrNull();
-  const DIE *EntryCU = Entry.getEntry().getUnitOrNull();
+  const DIE *EntryCU = Entry->getEntry().getUnitOrNull();
   if (!DieCU)
     // We assume that Die belongs to this CU, if it is not linked to any CU yet.
     DieCU = &getUnitDie();
@@ -460,7 +471,7 @@ void DwarfUnit::addBlockByrefAddress(const DbgVariable &DV, DIE &Die,
 
   // Decode the original location, and use that as the start of the byref
   // variable's location.
-  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+  DIELoc *Loc = new (DIEValueAllocator) DIELoc();
 
   bool validReg;
   if (Location.isReg())
@@ -577,7 +588,7 @@ static uint64_t getBaseTypeSize(DwarfDebug *DD, const DIDerivedType *Ty) {
 
 void DwarfUnit::addConstantFPValue(DIE &Die, const MachineOperand &MO) {
   assert(MO.isFPImm() && "Invalid machine operand!");
-  DIEBlock *Block = new (DIEValueAllocator) DIEBlock;
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
   APFloat FPImm = MO.getFPImm()->getValueAPF();
 
   // Get the raw data form of the floating point.
@@ -633,7 +644,7 @@ void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, bool Unsigned) {
     return;
   }
 
-  DIEBlock *Block = new (DIEValueAllocator) DIEBlock;
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
 
   // Get the raw data form of the large APInt.
   const uint64_t *Ptr64 = Val.getRawData();
@@ -766,7 +777,22 @@ void DwarfUnit::updateAcceleratorTables(const DIScope *Context,
 void DwarfUnit::addType(DIE &Entity, const DIType *Ty,
                         dwarf::Attribute Attribute) {
   assert(Ty && "Trying to add a type that doesn't exist?");
-  addDIEEntry(Entity, Attribute, DIEEntry(*getOrCreateTypeDIE(Ty)));
+
+  // Check for pre-existence.
+  DIEEntry *Entry = getDIEEntry(Ty);
+  // If it exists then use the existing value.
+  if (Entry) {
+    addDIEEntry(Entity, Attribute, Entry);
+    return;
+  }
+
+  // Construct type.
+  DIE *Buffer = getOrCreateTypeDIE(Ty);
+
+  // Set up proxy.
+  Entry = createDIEEntry(*Buffer);
+  insertDIEEntry(Ty, Entry);
+  addDIEEntry(Entity, Attribute, Entry);
 }
 
 std::string DwarfUnit::getParentContextString(const DIScope *Context) const {
@@ -943,6 +969,12 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
         if (unsigned PropertyAttributes = Property->getAttributes())
           addUInt(ElemDie, dwarf::DW_AT_APPLE_property_attribute, None,
                   PropertyAttributes);
+
+        DIEEntry *Entry = getDIEEntry(Element);
+        if (!Entry) {
+          Entry = createDIEEntry(ElemDie);
+          insertDIEEntry(Element, Entry);
+        }
       }
     }
 
@@ -1029,7 +1061,7 @@ void DwarfUnit::constructTemplateValueParameterDIE(
     else if (GlobalValue *GV = mdconst::dyn_extract<GlobalValue>(Val)) {
       // For declaration non-type template parameters (such as global values and
       // functions)
-      DIELoc *Loc = new (DIEValueAllocator) DIELoc;
+      DIELoc *Loc = new (DIEValueAllocator) DIELoc();
       addOpAddress(*Loc, Asm->getSymbol(GV));
       // Emit DW_OP_stack_value to use the address as the immediate value of the
       // parameter, rather than a pointer to it.
@@ -1322,7 +1354,7 @@ void DwarfUnit::constructMemberDIE(DIE &Buffer, const DIDerivedType *DT) {
     // expression to extract appropriate offset from vtable.
     // BaseAddr = ObAddr + *((*ObAddr) - Offset)
 
-    DIELoc *VBaseLocationDie = new (DIEValueAllocator) DIELoc;
+    DIELoc *VBaseLocationDie = new (DIEValueAllocator) DIELoc();
     addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_dup);
     addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
     addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
@@ -1361,7 +1393,7 @@ void DwarfUnit::constructMemberDIE(DIE &Buffer, const DIDerivedType *DT) {
       OffsetInBytes = DT->getOffsetInBits() >> 3;
 
     if (DD->getDwarfVersion() <= 2) {
-      DIELoc *MemLocationDie = new (DIEValueAllocator) DIELoc;
+      DIELoc *MemLocationDie = new (DIEValueAllocator) DIELoc();
       addUInt(*MemLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
       addUInt(*MemLocationDie, dwarf::DW_FORM_udata, OffsetInBytes);
       addBlock(MemberDie, dwarf::DW_AT_data_member_location, MemLocationDie);
@@ -1385,10 +1417,10 @@ void DwarfUnit::constructMemberDIE(DIE &Buffer, const DIDerivedType *DT) {
             dwarf::DW_VIRTUALITY_virtual);
 
   // Objective-C properties.
-  if (DINode *PNode = DT->getObjCProperty())
-    if (DIE *PDie = getDIE(PNode))
+  if (MDNode *PNode = DT->getObjCProperty())
+    if (DIEEntry *PropertyDie = getDIEEntry(PNode))
       MemberDie.addValue(dwarf::DW_AT_APPLE_property, dwarf::DW_FORM_ref4,
-                         DIEEntry(*PDie));
+                         PropertyDie);
 
   if (DT->isArtificial())
     addFlag(MemberDie, dwarf::DW_AT_artificial);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index e7e8267e0ed..0d01a9e9fb3 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -93,6 +93,10 @@ protected:
   /// information entries.
   DenseMap<const MDNode *, DIE *> MDNodeToDieMap;
 
+  /// Tracks the mapping of unit level debug information descriptors to debug
+  /// information entries using a DIEEntry proxy.
+  DenseMap<const MDNode *, DIEEntry *> MDNodeToDIEEntryMap;
+
   /// A list of all the DIEBlocks in use.
   std::vector<DIEBlock *> DIEBlocks;
 
@@ -107,6 +111,9 @@ protected:
   // All DIEValues are allocated through this allocator.
   BumpPtrAllocator DIEValueAllocator;
 
+  // A preallocated DIEValue because 1 is used frequently.
+  DIEInteger *DIEIntegerOne;
+
   /// The section this unit will be emitted in.
   MCSection *Section;
 
@@ -173,7 +180,7 @@ public:
   DIE *getDIE(const DINode *D) const;
 
   /// \brief Returns a fresh newly allocated DIELoc.
-  DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc; }
+  DIELoc *getDIELoc() { return new (DIEValueAllocator) DIELoc(); }
 
   /// \brief Insert DIE into the map.
   ///
@@ -226,7 +233,7 @@ public:
   void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry);
 
   /// \brief Add a DIE attribute data and value.
-  void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry Entry);
+  void addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIEEntry *Entry);
 
   void addDIETypeSignature(DIE &Die, const DwarfTypeUnit &Type);
 
@@ -362,12 +369,26 @@ private:
   /// If the DWARF version doesn't handle the language, return -1.
   int64_t getDefaultLowerBound() const;
 
+  /// \brief Returns the DIE entry for the specified debug variable.
+  DIEEntry *getDIEEntry(const MDNode *N) const {
+    return MDNodeToDIEEntryMap.lookup(N);
+  }
+
+  /// \brief Insert debug information entry into the map.
+  void insertDIEEntry(const MDNode *N, DIEEntry *E) {
+    MDNodeToDIEEntryMap.insert(std::make_pair(N, E));
+  }
+
   /// \brief Get an anonymous type for index type.
   DIE *getIndexTyDie();
 
   /// \brief Set D as anonymous type for index which can be reused later.
   void setIndexTyDie(DIE *D) { IndexTyDie = D; }
 
+  /// \brief Creates a new DIEEntry to be a proxy for a debug information
+  /// entry.
+  DIEEntry *createDIEEntry(DIE &Entry);
+
   /// If this is a named finished type then include it in the list of types for
   /// the accelerator tables.
   void updateAcceleratorTables(const DIScope *Context, const DIType *Ty,