X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FAsmPrinter%2FDwarfCompileUnit.cpp;h=73d0a839a7bc936c7c0271aebfc77443edb2870c;hb=b88831b204bcc1645097dafee64efa2b6a91df2d;hp=27ba19a89647c1231cc5d3de4ed24004966d3362;hpb=3eabc2adb7387c97da547e250997ed0a8d5e6d3d;p=oota-llvm.git

diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 27ba19a8964..73d0a839a7b 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -22,21 +22,35 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCStreamer.h"
 #include "llvm/Target/Mangler.h"
 #include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
 
 using namespace llvm;
 
+static cl::opt<bool> GenerateTypeUnits("generate-type-units", cl::Hidden,
+                                       cl::desc("Generate DWARF4 type units."),
+                                       cl::init(false));
+
 /// CompileUnit - Compile unit constructor.
-CompileUnit::CompileUnit(unsigned UID, DIE *D, const MDNode *N, AsmPrinter *A,
-                         DwarfDebug *DW, DwarfUnits *DWU)
-    : UniqueID(UID), Node(N), CUDie(D), Asm(A), DD(DW), DU(DWU), IndexTyDie(0),
-      DebugInfoOffset(0) {
+CompileUnit::CompileUnit(unsigned UID, DIE *D, DICompileUnit Node,
+                         AsmPrinter *A, DwarfDebug *DW, DwarfUnits *DWU)
+    : UniqueID(UID), Node(Node), Language(Node.getLanguage()), CUDie(D),
+      DebugInfoOffset(0), Asm(A), DD(DW), DU(DWU), IndexTyDie(0) {
+  DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1);
+  insertDIE(Node, D);
+}
+
+CompileUnit::CompileUnit(unsigned UID, DIE *D, uint16_t Language, AsmPrinter *A,
+                         DwarfDebug *DD, DwarfUnits *DU)
+    : UniqueID(UID), Node(NULL), Language(Language), CUDie(D),
+      DebugInfoOffset(0), Asm(A), DD(DD), DU(DU), IndexTyDie(0) {
   DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1);
-  insertDIE(N, D);
 }
 
 /// ~CompileUnit - Destructor for compile unit.
@@ -55,7 +69,7 @@ DIEEntry *CompileUnit::createDIEEntry(DIE *Entry) {
 /// getDefaultLowerBound - Return the default lower bound for an array. If the
 /// DWARF version doesn't handle the language, return -1.
 int64_t CompileUnit::getDefaultLowerBound() const {
-  switch (DICompileUnit(Node).getLanguage()) {
+  switch (getLanguage()) {
   default:
     break;
 
@@ -96,6 +110,41 @@ int64_t CompileUnit::getDefaultLowerBound() const {
   return -1;
 }
 
+/// Check whether the DIE for this MDNode can be shared across CUs.
+static bool isShareableAcrossCUs(DIDescriptor D) {
+  // When the MDNode can be part of the type system, the DIE can be shared
+  // across CUs.
+  // Combining type units and cross-CU DIE sharing is lower value (since
+  // cross-CU DIE sharing is used in LTO and removes type redundancy at that
+  // level already) but may be implementable for some value in projects
+  // building multiple independent libraries with LTO and then linking those
+  // together.
+  return (D.isType() ||
+          (D.isSubprogram() && !DISubprogram(D).isDefinition())) &&
+         !GenerateTypeUnits;
+}
+
+/// getDIE - Returns the debug information entry map slot for the
+/// specified debug variable. We delegate the request to DwarfDebug
+/// when the DIE for this MDNode can be shared across CUs. The mappings
+/// will be kept in DwarfDebug for shareable DIEs.
+DIE *CompileUnit::getDIE(DIDescriptor D) const {
+  if (isShareableAcrossCUs(D))
+    return DD->getDIE(D);
+  return MDNodeToDieMap.lookup(D);
+}
+
+/// insertDIE - Insert DIE into the map. We delegate the request to DwarfDebug
+/// when the DIE for this MDNode can be shared across CUs. The mappings
+/// will be kept in DwarfDebug for shareable DIEs.
+void CompileUnit::insertDIE(DIDescriptor Desc, DIE *D) {
+  if (isShareableAcrossCUs(Desc)) {
+    DD->insertDIE(Desc, D);
+    return;
+  }
+  MDNodeToDieMap.insert(std::make_pair(Desc, D));
+}
+
 /// addFlag - Add a flag that is true.
 void CompileUnit::addFlag(DIE *Die, dwarf::Attribute Attribute) {
   if (DD->getDwarfVersion() >= 4)
@@ -139,7 +188,8 @@ void CompileUnit::addSInt(DIEBlock *Die, Optional<dwarf::Form> Form,
 /// more predictable sizes. In the case of split dwarf we emit an index
 /// into another table which gets us the static offset into the string
 /// table.
-void CompileUnit::addString(DIE *Die, dwarf::Attribute Attribute, StringRef String) {
+void CompileUnit::addString(DIE *Die, dwarf::Attribute Attribute,
+                            StringRef String) {
   DIEValue *Value;
   dwarf::Form Form;
   if (!DD->useSplitDwarf()) {
@@ -184,8 +234,8 @@ void CompileUnit::addExpr(DIEBlock *Die, dwarf::Form Form, const MCExpr *Expr) {
 
 /// addLabel - Add a Dwarf label attribute data and value.
 ///
-void CompileUnit::addLabel(DIE *Die, dwarf::Attribute Attribute, dwarf::Form Form,
-                           const MCSymbol *Label) {
+void CompileUnit::addLabel(DIE *Die, dwarf::Attribute Attribute,
+                           dwarf::Form Form, const MCSymbol *Label) {
   DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
   Die->addValue(Attribute, Form, Value);
 }
@@ -195,6 +245,26 @@ void CompileUnit::addLabel(DIEBlock *Die, dwarf::Form Form,
   addLabel(Die, (dwarf::Attribute)0, Form, Label);
 }
 
+/// addSectionLabel - Add a Dwarf section label attribute data and value.
+///
+void CompileUnit::addSectionLabel(DIE *Die, dwarf::Attribute Attribute,
+                                  const MCSymbol *Label) {
+  if (DD->getDwarfVersion() >= 4)
+    addLabel(Die, Attribute, dwarf::DW_FORM_sec_offset, Label);
+  else
+    addLabel(Die, Attribute, dwarf::DW_FORM_data4, Label);
+}
+
+/// addSectionOffset - Add an offset into a section attribute data and value.
+///
+void CompileUnit::addSectionOffset(DIE *Die, dwarf::Attribute Attribute,
+                                   uint64_t Integer) {
+  if (DD->getDwarfVersion() >= 4)
+    addUInt(Die, Attribute, dwarf::DW_FORM_sec_offset, Integer);
+  else
+    addUInt(Die, Attribute, dwarf::DW_FORM_data4, Integer);
+}
+
 /// addLabelAddress - Add a dwarf label attribute data and value using
 /// DW_FORM_addr or DW_FORM_GNU_addr_index.
 ///
@@ -232,28 +302,45 @@ void CompileUnit::addOpAddress(DIEBlock *Die, const MCSymbol *Sym) {
   }
 }
 
-/// addDelta - Add a label delta attribute data and value.
+/// addSectionDelta - Add a section label delta attribute data and value.
 ///
-void CompileUnit::addDelta(DIE *Die, dwarf::Attribute Attribute, dwarf::Form Form,
-                           const MCSymbol *Hi, const MCSymbol *Lo) {
+void CompileUnit::addSectionDelta(DIE *Die, dwarf::Attribute Attribute,
+                                  const MCSymbol *Hi, const MCSymbol *Lo) {
   DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
-  Die->addValue(Attribute, Form, Value);
+  if (DD->getDwarfVersion() >= 4)
+    Die->addValue(Attribute, dwarf::DW_FORM_sec_offset, Value);
+  else
+    Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
 }
 
 /// addDIEEntry - Add a DIE attribute data and value.
 ///
-void CompileUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry) {
-  // We currently only use ref4.
-  Die->addValue(Attribute, dwarf::DW_FORM_ref4, createDIEEntry(Entry));
+void CompileUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute,
+                              DIE *Entry) {
+  addDIEEntry(Die, Attribute, createDIEEntry(Entry));
+}
+
+void CompileUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute,
+                              DIEEntry *Entry) {
+  const DIE *DieCU = Die->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 = getCUDie();
+  if (!EntryCU)
+    EntryCU = getCUDie();
+  Die->addValue(Attribute, EntryCU == DieCU ? dwarf::DW_FORM_ref4
+                                            : dwarf::DW_FORM_ref_addr,
+                Entry);
 }
 
 /// Create a DIE with the given Tag, add the DIE to its parent, and
 /// call insertDIE if MD is not null.
-DIE *CompileUnit::createAndAddDIE(unsigned Tag, DIE &Parent, const MDNode *MD) {
+DIE *CompileUnit::createAndAddDIE(unsigned Tag, DIE &Parent, DIDescriptor N) {
   DIE *Die = new DIE(Tag);
   Parent.addChild(Die);
-  if (MD)
-    insertDIE(MD, Die);
+  if (N)
+    insertDIE(N, Die);
   return Die;
 }
 
@@ -545,33 +632,31 @@ void CompileUnit::addBlockByrefAddress(const DbgVariable &DV, DIE *Die,
   StringRef varName = DV.getName();
 
   if (Tag == dwarf::DW_TAG_pointer_type) {
-    DIDerivedType DTy = DIDerivedType(Ty);
+    DIDerivedType DTy(Ty);
     TmpTy = resolve(DTy.getTypeDerivedFrom());
     isPointer = true;
   }
 
-  DICompositeType blockStruct = DICompositeType(TmpTy);
+  DICompositeType blockStruct(TmpTy);
 
   // Find the __forwarding field and the variable field in the __Block_byref
   // struct.
   DIArray Fields = blockStruct.getTypeArray();
-  DIDescriptor varField = DIDescriptor();
-  DIDescriptor forwardingField = DIDescriptor();
+  DIDerivedType varField;
+  DIDerivedType forwardingField;
 
   for (unsigned i = 0, N = Fields.getNumElements(); i < N; ++i) {
-    DIDescriptor Element = Fields.getElement(i);
-    DIDerivedType DT = DIDerivedType(Element);
+    DIDerivedType DT(Fields.getElement(i));
     StringRef fieldName = DT.getName();
     if (fieldName == "__forwarding")
-      forwardingField = Element;
+      forwardingField = DT;
     else if (fieldName == varName)
-      varField = Element;
+      varField = DT;
   }
 
   // Get the offsets for the forwarding field and the variable field.
-  unsigned forwardingFieldOffset =
-      DIDerivedType(forwardingField).getOffsetInBits() >> 3;
-  unsigned varFieldOffset = DIDerivedType(varField).getOffsetInBits() >> 3;
+  unsigned forwardingFieldOffset = forwardingField.getOffsetInBits() >> 3;
+  unsigned varFieldOffset = varField.getOffsetInBits() >> 2;
 
   // Decode the original location, and use that as the start of the byref
   // variable's location.
@@ -727,8 +812,7 @@ void CompileUnit::addConstantFPValue(DIE *Die, const MachineOperand &MO) {
 
   // Output the constant to DWARF one byte at a time.
   for (; Start != Stop; Start += Incr)
-    addUInt(Block, dwarf::DW_FORM_data1,
-            (unsigned char)0xFF & FltPtr[Start]);
+    addUInt(Block, dwarf::DW_FORM_data1, (unsigned char)0xFF & FltPtr[Start]);
 
   addBlock(Die, dwarf::DW_AT_const_value, Block);
 }
@@ -817,28 +901,46 @@ void CompileUnit::addTemplateParams(DIE &Buffer, DIArray TParams) {
 
 /// getOrCreateContextDIE - Get context owner's DIE.
 DIE *CompileUnit::getOrCreateContextDIE(DIScope Context) {
+  if (!Context || Context.isFile())
+    return getCUDie();
   if (Context.isType())
     return getOrCreateTypeDIE(DIType(Context));
-  else if (Context.isNameSpace())
+  if (Context.isNameSpace())
     return getOrCreateNameSpace(DINameSpace(Context));
-  else if (Context.isSubprogram())
+  if (Context.isSubprogram())
     return getOrCreateSubprogramDIE(DISubprogram(Context));
-  else
-    return getDIE(Context);
+  return getDIE(Context);
+}
+
+DIE *CompileUnit::createTypeDIE(DICompositeType Ty) {
+  DIE *ContextDIE = getOrCreateContextDIE(resolve(Ty.getContext()));
+
+  DIE *TyDIE = getDIE(Ty);
+  if (TyDIE)
+    return TyDIE;
+
+  // Create new type.
+  TyDIE = createAndAddDIE(Ty.getTag(), *ContextDIE, Ty);
+
+  constructTypeDIEImpl(*TyDIE, Ty);
+
+  updateAcceleratorTables(Ty, TyDIE);
+  return TyDIE;
 }
 
 /// getOrCreateTypeDIE - Find existing DIE or create new DIE for the
 /// given DIType.
 DIE *CompileUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
-  DIType Ty(TyNode);
-  if (!Ty.isType())
+  if (!TyNode)
     return NULL;
 
+  DIType Ty(TyNode);
+  assert(Ty.isType());
+
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
   DIE *ContextDIE = getOrCreateContextDIE(resolve(Ty.getContext()));
-  if (!ContextDIE)
-    ContextDIE = CUDie.get();
+  assert(ContextDIE);
 
   DIE *TyDIE = getDIE(Ty);
   if (TyDIE)
@@ -855,8 +957,13 @@ DIE *CompileUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
     assert(Ty.isDerivedType() && "Unknown kind of DIType");
     constructTypeDIE(*TyDIE, DIDerivedType(Ty));
   }
-  // If this is a named finished type then include it in the list of types
-  // for the accelerator tables.
+
+  updateAcceleratorTables(Ty, TyDIE);
+
+  return TyDIE;
+}
+
+void CompileUnit::updateAcceleratorTables(DIType Ty, const DIE *TyDIE) {
   if (!Ty.getName().empty() && !Ty.isForwardDecl()) {
     bool IsImplementation = 0;
     if (Ty.isCompositeType()) {
@@ -868,8 +975,6 @@ DIE *CompileUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
     unsigned Flags = IsImplementation ? dwarf::DW_FLAG_type_implementation : 0;
     addAccelType(Ty.getName(), std::make_pair(TyDIE, Flags));
   }
-
-  return TyDIE;
 }
 
 /// addType - Add a new type attribute to the specified entity.
@@ -880,7 +985,7 @@ void CompileUnit::addType(DIE *Entity, DIType Ty, dwarf::Attribute Attribute) {
   DIEEntry *Entry = getDIEEntry(Ty);
   // If it exists then use the existing value.
   if (Entry) {
-    Entity->addValue(Attribute, dwarf::DW_FORM_ref4, Entry);
+    addDIEEntry(Entity, Attribute, Entry);
     return;
   }
 
@@ -890,7 +995,7 @@ void CompileUnit::addType(DIE *Entity, DIType Ty, dwarf::Attribute Attribute) {
   // Set up proxy.
   Entry = createDIEEntry(Buffer);
   insertDIEEntry(Ty, Entry);
-  Entity->addValue(Attribute, dwarf::DW_FORM_ref4, Entry);
+  addDIEEntry(Entity, Attribute, Entry);
 
   // If this is a complete composite type then include it in the
   // list of global types.
@@ -901,27 +1006,28 @@ void CompileUnit::addType(DIE *Entity, DIType Ty, dwarf::Attribute Attribute) {
 // DIE to the proper table while ensuring that the name that we're going
 // to reference is in the string table. We do this since the names we
 // add may not only be identical to the names in the DIE.
-void CompileUnit::addAccelName(StringRef Name, DIE *Die) {
+void CompileUnit::addAccelName(StringRef Name, const DIE *Die) {
   DU->getStringPoolEntry(Name);
-  std::vector<DIE *> &DIEs = AccelNames[Name];
+  std::vector<const DIE *> &DIEs = AccelNames[Name];
   DIEs.push_back(Die);
 }
 
-void CompileUnit::addAccelObjC(StringRef Name, DIE *Die) {
+void CompileUnit::addAccelObjC(StringRef Name, const DIE *Die) {
   DU->getStringPoolEntry(Name);
-  std::vector<DIE *> &DIEs = AccelObjC[Name];
+  std::vector<const DIE *> &DIEs = AccelObjC[Name];
   DIEs.push_back(Die);
 }
 
-void CompileUnit::addAccelNamespace(StringRef Name, DIE *Die) {
+void CompileUnit::addAccelNamespace(StringRef Name, const DIE *Die) {
   DU->getStringPoolEntry(Name);
-  std::vector<DIE *> &DIEs = AccelNamespace[Name];
+  std::vector<const DIE *> &DIEs = AccelNamespace[Name];
   DIEs.push_back(Die);
 }
 
-void CompileUnit::addAccelType(StringRef Name, std::pair<DIE *, unsigned> Die) {
+void CompileUnit::addAccelType(StringRef Name,
+                               std::pair<const DIE *, unsigned> Die) {
   DU->getStringPoolEntry(Name);
-  std::vector<std::pair<DIE *, unsigned> > &DIEs = AccelTypes[Name];
+  std::vector<std::pair<const DIE *, unsigned> > &DIEs = AccelTypes[Name];
   DIEs.push_back(Die);
 }
 
@@ -1063,6 +1169,9 @@ static bool isTypeUnitScoped(DIType Ty, const DwarfDebug *DD) {
 
 /// Return true if the type should be split out into a type unit.
 static bool shouldCreateTypeUnit(DICompositeType CTy, const DwarfDebug *DD) {
+  if (!GenerateTypeUnits)
+    return false;
+
   uint16_t Tag = CTy.getTag();
 
   switch (Tag) {
@@ -1081,7 +1190,16 @@ static bool shouldCreateTypeUnit(DICompositeType CTy, const DwarfDebug *DD) {
 
 /// constructTypeDIE - Construct type DIE from DICompositeType.
 void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
-  // Get core information.
+  // If this is a type applicable to a type unit it then add it to the
+  // list of types we'll compute a hash for later.
+  if (shouldCreateTypeUnit(CTy, DD))
+    DD->addTypeUnitType(&Buffer, CTy);
+  else
+    constructTypeDIEImpl(Buffer, CTy);
+}
+
+void CompileUnit::constructTypeDIEImpl(DIE &Buffer, DICompositeType CTy) {
+  // Add name if not anonymous or intermediate type.
   StringRef Name = CTy.getName();
 
   uint64_t Size = CTy.getSizeInBits() >> 3;
@@ -1089,29 +1207,17 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
 
   switch (Tag) {
   case dwarf::DW_TAG_array_type:
-    constructArrayTypeDIE(Buffer, &CTy);
+    constructArrayTypeDIE(Buffer, CTy);
+    break;
+  case dwarf::DW_TAG_enumeration_type:
+    constructEnumTypeDIE(Buffer, CTy);
     break;
-  case dwarf::DW_TAG_enumeration_type: {
-    DIArray Elements = CTy.getTypeArray();
-
-    // Add enumerators to enumeration type.
-    for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
-      DIDescriptor Enum(Elements.getElement(i));
-      if (Enum.isEnumerator())
-        constructEnumTypeDIE(Buffer, DIEnumerator(Enum));
-    }
-    DIType DTy = resolve(CTy.getTypeDerivedFrom());
-    if (DTy) {
-      addType(&Buffer, DTy);
-      addFlag(&Buffer, dwarf::DW_AT_enum_class);
-    }
-  } break;
   case dwarf::DW_TAG_subroutine_type: {
     // Add return type. A void return won't have a type.
     DIArray Elements = CTy.getTypeArray();
-    DIDescriptor RTy = Elements.getElement(0);
+    DIType RTy(Elements.getElement(0));
     if (RTy)
-      addType(&Buffer, DIType(RTy));
+      addType(&Buffer, RTy);
 
     bool isPrototyped = true;
     // Add arguments.
@@ -1129,7 +1235,7 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
     }
     // Add prototype flag if we're dealing with a C language and the
     // function has been prototyped.
-    uint16_t Language = DICompileUnit(Node).getLanguage();
+    uint16_t Language = getLanguage();
     if (isPrototyped &&
         (Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
          Language == dwarf::DW_LANG_ObjC))
@@ -1145,7 +1251,7 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
       DIE *ElemDie = NULL;
       if (Element.isSubprogram()) {
         DISubprogram SP(Element);
-        ElemDie = getOrCreateSubprogramDIE(DISubprogram(Element));
+        ElemDie = getOrCreateSubprogramDIE(SP);
         if (SP.isProtected())
           addUInt(ElemDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
                   dwarf::DW_ACCESS_protected);
@@ -1211,9 +1317,9 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
       addFlag(&Buffer, dwarf::DW_AT_APPLE_block);
 
     DICompositeType ContainingType(resolve(CTy.getContainingType()));
-    if (DIDescriptor(ContainingType).isCompositeType())
+    if (ContainingType)
       addDIEEntry(&Buffer, dwarf::DW_AT_containing_type,
-                  getOrCreateTypeDIE(DIType(ContainingType)));
+                  getOrCreateTypeDIE(ContainingType));
 
     if (CTy.isObjcClassComplete())
       addFlag(&Buffer, dwarf::DW_AT_APPLE_objc_complete_type);
@@ -1259,10 +1365,6 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
       addUInt(&Buffer, dwarf::DW_AT_APPLE_runtime_class, dwarf::DW_FORM_data1,
               RLang);
   }
-  // If this is a type applicable to a type unit it then add it to the
-  // list of types we'll compute a hash for later.
-  if (shouldCreateTypeUnit(CTy, DD))
-    DD->addTypeUnitType(&Buffer);
 }
 
 /// constructTemplateTypeParameterDIE - Construct new DIE for the given
@@ -1322,10 +1424,6 @@ DIE *CompileUnit::getOrCreateNameSpace(DINameSpace NS) {
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
   DIE *ContextDIE = getOrCreateContextDIE(NS.getContext());
-  if (!ContextDIE)
-    // If the context is null, DIE should belong to the CU we call construct
-    // function on.
-    ContextDIE = CUDie.get();
 
   DIE *NDie = getDIE(NS);
   if (NDie)
@@ -1348,8 +1446,6 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
   // such construction creates the DIE (as is the case for member function
   // declarations).
   DIE *ContextDIE = getOrCreateContextDIE(resolve(SP.getContext()));
-  if (!ContextDIE)
-    ContextDIE = CUDie.get();
 
   DIE *SPDie = getDIE(SP);
   if (SPDie)
@@ -1393,7 +1489,7 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
 
   // Add the prototype if we have a prototype and we have a C like
   // language.
-  uint16_t Language = DICompileUnit(Node).getLanguage();
+  uint16_t Language = getLanguage();
   if (SP.isPrototyped() &&
       (Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
        Language == dwarf::DW_LANG_ObjC))
@@ -1416,8 +1512,8 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
     addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
     addUInt(Block, dwarf::DW_FORM_udata, SP.getVirtualIndex());
     addBlock(SPDie, dwarf::DW_AT_vtable_elem_location, Block);
-    ContainingTypeMap.insert(std::make_pair(SPDie,
-                                            resolve(SP.getContainingType())));
+    ContainingTypeMap.insert(
+        std::make_pair(SPDie, resolve(SP.getContainingType())));
   }
 
   if (!SP.isDefinition()) {
@@ -1427,7 +1523,7 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
     // be handled while processing variables.
     for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) {
       DIE *Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, *SPDie);
-      DIType ATy = DIType(Args.getElement(i));
+      DIType ATy(Args.getElement(i));
       addType(Arg, ATy);
       if (ATy.isArtificial())
         addFlag(Arg, dwarf::DW_AT_artificial);
@@ -1478,12 +1574,11 @@ static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
 }
 
 /// createGlobalVariableDIE - create global variable DIE.
-void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
+void CompileUnit::createGlobalVariableDIE(DIGlobalVariable GV) {
   // Check for pre-existence.
-  if (getDIE(N))
+  if (getDIE(GV))
     return;
 
-  DIGlobalVariable GV(N);
   if (!GV.isGlobalVariable())
     return;
 
@@ -1508,11 +1603,9 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     // Construct the context before querying for the existence of the DIE in
     // case such construction creates the DIE.
     DIE *ContextDIE = getOrCreateContextDIE(GVContext);
-    if (!ContextDIE)
-      ContextDIE = CUDie.get();
 
     // Add to map.
-    VariableDIE = createAndAddDIE(GV.getTag(), *ContextDIE, N);
+    VariableDIE = createAndAddDIE(GV.getTag(), *ContextDIE, GV);
 
     // Add name and type.
     addString(VariableDIE, dwarf::DW_AT_name, GV.getDisplayName());
@@ -1562,7 +1655,7 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     if (GVContext && GV.isDefinition() && !GVContext.isCompileUnit() &&
         !GVContext.isFile() && !DD->isSubprogramContext(GVContext)) {
       // Create specification DIE.
-      VariableSpecDIE = createAndAddDIE(dwarf::DW_TAG_variable, *CUDie.get());
+      VariableSpecDIE = createAndAddDIE(dwarf::DW_TAG_variable, *CUDie);
       addDIEEntry(VariableSpecDIE, dwarf::DW_AT_specification, VariableDIE);
       addBlock(VariableSpecDIE, dwarf::DW_AT_location, Block);
       // A static member's declaration is already flagged as such.
@@ -1588,7 +1681,7 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     // it is not a static member.
     if (!IsStaticMember)
       addConstantValue(VariableDIE, CI, isUnsignedDIType(DD, GTy));
-  } else if (const ConstantExpr *CE = getMergedGlobalExpr(N->getOperand(11))) {
+  } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV->getOperand(11))) {
     addToAccelTable = true;
     // GV is a merged global.
     DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
@@ -1639,16 +1732,17 @@ void CompileUnit::constructSubrangeDIE(DIE &Buffer, DISubrange SR,
   if (Count != -1 && Count != 0)
     // FIXME: An unbounded array should reference the expression that defines
     // the array.
-    addUInt(DW_Subrange, dwarf::DW_AT_upper_bound, None, LowerBound + Count - 1);
+    addUInt(DW_Subrange, dwarf::DW_AT_upper_bound, None,
+            LowerBound + Count - 1);
 }
 
 /// constructArrayTypeDIE - Construct array type DIE from DICompositeType.
-void CompileUnit::constructArrayTypeDIE(DIE &Buffer, DICompositeType *CTy) {
-  if (CTy->isVector())
+void CompileUnit::constructArrayTypeDIE(DIE &Buffer, DICompositeType CTy) {
+  if (CTy.isVector())
     addFlag(&Buffer, dwarf::DW_AT_GNU_vector);
 
   // Emit the element type.
-  addType(&Buffer, resolve(CTy->getTypeDerivedFrom()));
+  addType(&Buffer, resolve(CTy.getTypeDerivedFrom()));
 
   // Get an anonymous type for index type.
   // FIXME: This type should be passed down from the front end
@@ -1665,7 +1759,7 @@ void CompileUnit::constructArrayTypeDIE(DIE &Buffer, DICompositeType *CTy) {
   }
 
   // Add subranges to array type.
-  DIArray Elements = CTy->getTypeArray();
+  DIArray Elements = CTy.getTypeArray();
   for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
     DIDescriptor Element = Elements.getElement(i);
     if (Element.getTag() == dwarf::DW_TAG_subrange_type)
@@ -1673,13 +1767,27 @@ void CompileUnit::constructArrayTypeDIE(DIE &Buffer, DICompositeType *CTy) {
   }
 }
 
-/// constructEnumTypeDIE - Construct enum type DIE from DIEnumerator.
-void CompileUnit::constructEnumTypeDIE(DIE &Buffer, DIEnumerator ETy) {
-  DIE *Enumerator = createAndAddDIE(dwarf::DW_TAG_enumerator, Buffer);
-  StringRef Name = ETy.getName();
-  addString(Enumerator, dwarf::DW_AT_name, Name);
-  int64_t Value = ETy.getEnumValue();
-  addSInt(Enumerator, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata, Value);
+/// constructEnumTypeDIE - Construct an enum type DIE from DICompositeType.
+void CompileUnit::constructEnumTypeDIE(DIE &Buffer, DICompositeType CTy) {
+  DIArray Elements = CTy.getTypeArray();
+
+  // Add enumerators to enumeration type.
+  for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
+    DIEnumerator Enum(Elements.getElement(i));
+    if (Enum.isEnumerator()) {
+      DIE *Enumerator = createAndAddDIE(dwarf::DW_TAG_enumerator, Buffer);
+      StringRef Name = Enum.getName();
+      addString(Enumerator, dwarf::DW_AT_name, Name);
+      int64_t Value = Enum.getEnumValue();
+      addSInt(Enumerator, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata,
+              Value);
+    }
+  }
+  DIType DTy = resolve(CTy.getTypeDerivedFrom());
+  if (DTy) {
+    addType(&Buffer, DTy);
+    addFlag(&Buffer, dwarf::DW_AT_enum_class);
+  }
 }
 
 /// constructContainingTypeDIEs - Construct DIEs for types that contain
@@ -1689,10 +1797,10 @@ void CompileUnit::constructContainingTypeDIEs() {
                                                  CE = ContainingTypeMap.end();
        CI != CE; ++CI) {
     DIE *SPDie = CI->first;
-    const MDNode *N = CI->second;
-    if (!N)
+    DIDescriptor D(CI->second);
+    if (!D)
       continue;
-    DIE *NDie = getDIE(N);
+    DIE *NDie = getDIE(D);
     if (!NDie)
       continue;
     addDIEEntry(SPDie, dwarf::DW_AT_containing_type, NDie);
@@ -1700,42 +1808,42 @@ void CompileUnit::constructContainingTypeDIEs() {
 }
 
 /// constructVariableDIE - Construct a DIE for the given DbgVariable.
-DIE *CompileUnit::constructVariableDIE(DbgVariable *DV, bool isScopeAbstract) {
-  StringRef Name = DV->getName();
+DIE *CompileUnit::constructVariableDIE(DbgVariable &DV, bool isScopeAbstract) {
+  StringRef Name = DV.getName();
 
   // Define variable debug information entry.
-  DIE *VariableDie = new DIE(DV->getTag());
-  DbgVariable *AbsVar = DV->getAbstractVariable();
+  DIE *VariableDie = new DIE(DV.getTag());
+  DbgVariable *AbsVar = DV.getAbstractVariable();
   DIE *AbsDIE = AbsVar ? AbsVar->getDIE() : NULL;
   if (AbsDIE)
     addDIEEntry(VariableDie, dwarf::DW_AT_abstract_origin, AbsDIE);
   else {
     if (!Name.empty())
       addString(VariableDie, dwarf::DW_AT_name, Name);
-    addSourceLine(VariableDie, DV->getVariable());
-    addType(VariableDie, DV->getType());
+    addSourceLine(VariableDie, DV.getVariable());
+    addType(VariableDie, DV.getType());
   }
 
-  if (DV->isArtificial())
+  if (DV.isArtificial())
     addFlag(VariableDie, dwarf::DW_AT_artificial);
 
   if (isScopeAbstract) {
-    DV->setDIE(VariableDie);
+    DV.setDIE(VariableDie);
     return VariableDie;
   }
 
   // Add variable address.
 
-  unsigned Offset = DV->getDotDebugLocOffset();
+  unsigned Offset = DV.getDotDebugLocOffset();
   if (Offset != ~0U) {
-    addLabel(VariableDie, dwarf::DW_AT_location, dwarf::DW_FORM_data4,
-             Asm->GetTempSymbol("debug_loc", Offset));
-    DV->setDIE(VariableDie);
+    addSectionLabel(VariableDie, dwarf::DW_AT_location,
+                    Asm->GetTempSymbol("debug_loc", Offset));
+    DV.setDIE(VariableDie);
     return VariableDie;
   }
 
   // Check if variable is described by a DBG_VALUE instruction.
-  if (const MachineInstr *DVInsn = DV->getMInsn()) {
+  if (const MachineInstr *DVInsn = DV.getMInsn()) {
     assert(DVInsn->getNumOperands() == 3);
     if (DVInsn->getOperand(0).isReg()) {
       const MachineOperand RegOp = DVInsn->getOperand(0);
@@ -1743,32 +1851,32 @@ DIE *CompileUnit::constructVariableDIE(DbgVariable *DV, bool isScopeAbstract) {
       if (DVInsn->getOperand(1).isImm()) {
         MachineLocation Location(RegOp.getReg(),
                                  DVInsn->getOperand(1).getImm());
-        addVariableAddress(*DV, VariableDie, Location);
+        addVariableAddress(DV, VariableDie, Location);
       } else if (RegOp.getReg())
-        addVariableAddress(*DV, VariableDie, MachineLocation(RegOp.getReg()));
+        addVariableAddress(DV, VariableDie, MachineLocation(RegOp.getReg()));
     } else if (DVInsn->getOperand(0).isImm())
-      addConstantValue(VariableDie, DVInsn->getOperand(0), DV->getType());
+      addConstantValue(VariableDie, DVInsn->getOperand(0), DV.getType());
     else if (DVInsn->getOperand(0).isFPImm())
       addConstantFPValue(VariableDie, DVInsn->getOperand(0));
     else if (DVInsn->getOperand(0).isCImm())
       addConstantValue(VariableDie, DVInsn->getOperand(0).getCImm(),
-                       isUnsignedDIType(DD, DV->getType()));
+                       isUnsignedDIType(DD, DV.getType()));
 
-    DV->setDIE(VariableDie);
+    DV.setDIE(VariableDie);
     return VariableDie;
   } else {
     // .. else use frame index.
-    int FI = DV->getFrameIndex();
+    int FI = DV.getFrameIndex();
     if (FI != ~0) {
       unsigned FrameReg = 0;
       const TargetFrameLowering *TFI = Asm->TM.getFrameLowering();
       int Offset = TFI->getFrameIndexReference(*Asm->MF, FI, FrameReg);
       MachineLocation Location(FrameReg, Offset);
-      addVariableAddress(*DV, VariableDie, Location);
+      addVariableAddress(DV, VariableDie, Location);
     }
   }
 
-  DV->setDIE(VariableDie);
+  DV.setDIE(VariableDie);
   return VariableDie;
 }
 
@@ -1786,34 +1894,6 @@ void CompileUnit::constructMemberDIE(DIE &Buffer, DIDerivedType DT) {
   DIEBlock *MemLocationDie = new (DIEValueAllocator) DIEBlock();
   addUInt(MemLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
 
-  uint64_t Size = DT.getSizeInBits();
-  uint64_t FieldSize = getBaseTypeSize(DD, DT);
-
-  if (Size != FieldSize) {
-    // Handle bitfield.
-    addUInt(MemberDie, dwarf::DW_AT_byte_size, None,
-            getBaseTypeSize(DD, DT) >> 3);
-    addUInt(MemberDie, dwarf::DW_AT_bit_size, None, DT.getSizeInBits());
-
-    uint64_t Offset = DT.getOffsetInBits();
-    uint64_t AlignMask = ~(DT.getAlignInBits() - 1);
-    uint64_t HiMark = (Offset + FieldSize) & AlignMask;
-    uint64_t FieldOffset = (HiMark - FieldSize);
-    Offset -= FieldOffset;
-
-    // Maybe we need to work from the other end.
-    if (Asm->getDataLayout().isLittleEndian())
-      Offset = FieldSize - (Offset + Size);
-    addUInt(MemberDie, dwarf::DW_AT_bit_offset, None, Offset);
-
-    // Here WD_AT_data_member_location points to the anonymous
-    // field that includes this bit field.
-    addUInt(MemLocationDie, dwarf::DW_FORM_udata, FieldOffset >> 3);
-
-  } else
-    // This is not a bitfield.
-    addUInt(MemLocationDie, dwarf::DW_FORM_udata, DT.getOffsetInBits() >> 3);
-
   if (DT.getTag() == dwarf::DW_TAG_inheritance && DT.isVirtual()) {
 
     // For C++, virtual base classes are not at fixed offset. Use following
@@ -1830,8 +1910,36 @@ void CompileUnit::constructMemberDIE(DIE &Buffer, DIDerivedType DT) {
     addUInt(VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
 
     addBlock(MemberDie, dwarf::DW_AT_data_member_location, VBaseLocationDie);
-  } else
-    addBlock(MemberDie, dwarf::DW_AT_data_member_location, MemLocationDie);
+  } else {
+    uint64_t Size = DT.getSizeInBits();
+    uint64_t FieldSize = getBaseTypeSize(DD, DT);
+    uint64_t OffsetInBytes;
+
+    if (Size != FieldSize) {
+      // Handle bitfield.
+      addUInt(MemberDie, dwarf::DW_AT_byte_size, None,
+              getBaseTypeSize(DD, DT) >> 3);
+      addUInt(MemberDie, dwarf::DW_AT_bit_size, None, DT.getSizeInBits());
+
+      uint64_t Offset = DT.getOffsetInBits();
+      uint64_t AlignMask = ~(DT.getAlignInBits() - 1);
+      uint64_t HiMark = (Offset + FieldSize) & AlignMask;
+      uint64_t FieldOffset = (HiMark - FieldSize);
+      Offset -= FieldOffset;
+
+      // Maybe we need to work from the other end.
+      if (Asm->getDataLayout().isLittleEndian())
+        Offset = FieldSize - (Offset + Size);
+      addUInt(MemberDie, dwarf::DW_AT_bit_offset, None, Offset);
+
+      // Here WD_AT_data_member_location points to the anonymous
+      // field that includes this bit field.
+      OffsetInBytes = FieldOffset >> 3;
+    } else
+      // This is not a bitfield.
+      OffsetInBytes = DT.getOffsetInBits() >> 3;
+    addUInt(MemberDie, dwarf::DW_AT_data_member_location, None, OffsetInBytes);
+  }
 
   if (DT.isProtected())
     addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
@@ -1858,14 +1966,15 @@ void CompileUnit::constructMemberDIE(DIE &Buffer, DIDerivedType DT) {
 }
 
 /// getOrCreateStaticMemberDIE - Create new DIE for C++ static member.
-DIE *CompileUnit::getOrCreateStaticMemberDIE(const DIDerivedType DT) {
+DIE *CompileUnit::getOrCreateStaticMemberDIE(DIDerivedType DT) {
   if (!DT.Verify())
     return NULL;
 
   // Construct the context before querying for the existence of the DIE in case
   // such construction creates the DIE.
   DIE *ContextDIE = getOrCreateContextDIE(resolve(DT.getContext()));
-  assert(ContextDIE && "Static member should belong to a non-CU context.");
+  assert(dwarf::isType(ContextDIE->getTag()) &&
+         "Static member should belong to a type.");
 
   DIE *StaticMemberDIE = getDIE(DT);
   if (StaticMemberDIE)
@@ -1900,3 +2009,14 @@ DIE *CompileUnit::getOrCreateStaticMemberDIE(const DIDerivedType DT) {
 
   return StaticMemberDIE;
 }
+
+void CompileUnit::emitHeader(const MCSection *ASection,
+                             const MCSymbol *ASectionSym) {
+  Asm->OutStreamer.AddComment("DWARF version number");
+  Asm->EmitInt16(DD->getDwarfVersion());
+  Asm->OutStreamer.AddComment("Offset Into Abbrev. Section");
+  Asm->EmitSectionOffset(Asm->GetTempSymbol(ASection->getLabelBeginName()),
+                         ASectionSym);
+  Asm->OutStreamer.AddComment("Address Size (in bytes)");
+  Asm->EmitInt8(Asm->getDataLayout().getPointerSize());
+}