--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,1956 @@
+//===-- llvm/CodeGen/DwarfCompileUnit.cpp - Dwarf Compile Unit ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for constructing a dwarf compile unit.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "dwarfdebug"
+
+#include "DwarfCompileUnit.h"
+#include "DwarfAccelTable.h"
+#include "DwarfDebug.h"
+#include "llvm/ADT/APFloat.h"
+#include "llvm/DIBuilder.h"
+#include "llvm/IR/Constants.h"
+#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"
+
+using namespace llvm;
+
+/// CompileUnit - Compile unit constructor.
+CompileUnit::CompileUnit(unsigned UID, DIE *D, DICompileUnit Node,
+                         AsmPrinter *A, DwarfDebug *DW, DwarfUnits *DWU)
+    : UniqueID(UID), Node(Node), CUDie(D), Asm(A), DD(DW), DU(DWU),
+      IndexTyDie(0), DebugInfoOffset(0) {
+  DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1);
+  insertDIE(Node, D);
+}
+
+/// ~CompileUnit - Destructor for compile unit.
+CompileUnit::~CompileUnit() {
+  for (unsigned j = 0, M = DIEBlocks.size(); j < M; ++j)
+    DIEBlocks[j]->~DIEBlock();
+}
+
+/// createDIEEntry - Creates a new DIEEntry to be a proxy for a debug
+/// information entry.
+DIEEntry *CompileUnit::createDIEEntry(DIE *Entry) {
+  DIEEntry *Value = new (DIEValueAllocator) DIEEntry(Entry);
+  return Value;
+}
+
+/// 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 (getLanguage()) {
+  default:
+    break;
+
+  case dwarf::DW_LANG_C89:
+  case dwarf::DW_LANG_C99:
+  case dwarf::DW_LANG_C:
+  case dwarf::DW_LANG_C_plus_plus:
+  case dwarf::DW_LANG_ObjC:
+  case dwarf::DW_LANG_ObjC_plus_plus:
+    return 0;
+
+  case dwarf::DW_LANG_Fortran77:
+  case dwarf::DW_LANG_Fortran90:
+  case dwarf::DW_LANG_Fortran95:
+    return 1;
+
+  // The languages below have valid values only if the DWARF version >= 4.
+  case dwarf::DW_LANG_Java:
+  case dwarf::DW_LANG_Python:
+  case dwarf::DW_LANG_UPC:
+  case dwarf::DW_LANG_D:
+    if (dwarf::DWARF_VERSION >= 4)
+      return 0;
+    break;
+
+  case dwarf::DW_LANG_Ada83:
+  case dwarf::DW_LANG_Ada95:
+  case dwarf::DW_LANG_Cobol74:
+  case dwarf::DW_LANG_Cobol85:
+  case dwarf::DW_LANG_Modula2:
+  case dwarf::DW_LANG_Pascal83:
+  case dwarf::DW_LANG_PLI:
+    if (dwarf::DWARF_VERSION >= 4)
+      return 1;
+    break;
+  }
+
+  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.
+  return D.isType() ||
+         (D.isSubprogram() && !DISubprogram(D).isDefinition());
+}
+
+/// 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)
+    Die->addValue(Attribute, dwarf::DW_FORM_flag_present, DIEIntegerOne);
+  else
+    Die->addValue(Attribute, dwarf::DW_FORM_flag, DIEIntegerOne);
+}
+
+/// addUInt - Add an unsigned integer attribute data and value.
+///
+void CompileUnit::addUInt(DIE *Die, dwarf::Attribute Attribute,
+                          Optional<dwarf::Form> Form, uint64_t Integer) {
+  if (!Form)
+    Form = DIEInteger::BestForm(false, Integer);
+  DIEValue *Value = Integer == 1 ? DIEIntegerOne : new (DIEValueAllocator)
+                        DIEInteger(Integer);
+  Die->addValue(Attribute, *Form, Value);
+}
+
+void CompileUnit::addUInt(DIEBlock *Block, dwarf::Form Form, uint64_t Integer) {
+  addUInt(Block, (dwarf::Attribute)0, Form, Integer);
+}
+
+/// addSInt - Add an signed integer attribute data and value.
+///
+void CompileUnit::addSInt(DIE *Die, dwarf::Attribute Attribute,
+                          Optional<dwarf::Form> Form, int64_t Integer) {
+  if (!Form)
+    Form = DIEInteger::BestForm(true, Integer);
+  DIEValue *Value = new (DIEValueAllocator) DIEInteger(Integer);
+  Die->addValue(Attribute, *Form, Value);
+}
+
+void CompileUnit::addSInt(DIEBlock *Die, Optional<dwarf::Form> Form,
+                          int64_t Integer) {
+  addSInt(Die, (dwarf::Attribute)0, Form, Integer);
+}
+
+/// addString - Add a string attribute data and value. We always emit a
+/// reference to the string pool instead of immediate strings so that DIEs have
+/// 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) {
+  DIEValue *Value;
+  dwarf::Form Form;
+  if (!DD->useSplitDwarf()) {
+    MCSymbol *Symb = DU->getStringPoolEntry(String);
+    if (Asm->needsRelocationsForDwarfStringPool())
+      Value = new (DIEValueAllocator) DIELabel(Symb);
+    else {
+      MCSymbol *StringPool = DU->getStringPoolSym();
+      Value = new (DIEValueAllocator) DIEDelta(Symb, StringPool);
+    }
+    Form = dwarf::DW_FORM_strp;
+  } else {
+    unsigned idx = DU->getStringPoolIndex(String);
+    Value = new (DIEValueAllocator) DIEInteger(idx);
+    Form = dwarf::DW_FORM_GNU_str_index;
+  }
+  DIEValue *Str = new (DIEValueAllocator) DIEString(Value, String);
+  Die->addValue(Attribute, Form, Str);
+}
+
+/// addLocalString - Add a string attribute data and value. This is guaranteed
+/// to be in the local string pool instead of indirected.
+void CompileUnit::addLocalString(DIE *Die, dwarf::Attribute Attribute,
+                                 StringRef String) {
+  MCSymbol *Symb = DU->getStringPoolEntry(String);
+  DIEValue *Value;
+  if (Asm->needsRelocationsForDwarfStringPool())
+    Value = new (DIEValueAllocator) DIELabel(Symb);
+  else {
+    MCSymbol *StringPool = DU->getStringPoolSym();
+    Value = new (DIEValueAllocator) DIEDelta(Symb, StringPool);
+  }
+  Die->addValue(Attribute, dwarf::DW_FORM_strp, Value);
+}
+
+/// addExpr - Add a Dwarf expression attribute data and value.
+///
+void CompileUnit::addExpr(DIEBlock *Die, dwarf::Form Form, const MCExpr *Expr) {
+  DIEValue *Value = new (DIEValueAllocator) DIEExpr(Expr);
+  Die->addValue((dwarf::Attribute)0, Form, Value);
+}
+
+/// addLabel - Add a Dwarf label attribute data and value.
+///
+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);
+}
+
+void CompileUnit::addLabel(DIEBlock *Die, dwarf::Form Form,
+                           const MCSymbol *Label) {
+  addLabel(Die, (dwarf::Attribute)0, Form, Label);
+}
+
+/// addLabelAddress - Add a dwarf label attribute data and value using
+/// DW_FORM_addr or DW_FORM_GNU_addr_index.
+///
+void CompileUnit::addLabelAddress(DIE *Die, dwarf::Attribute Attribute,
+                                  MCSymbol *Label) {
+  if (Label)
+    DD->addArangeLabel(SymbolCU(this, Label));
+
+  if (!DD->useSplitDwarf()) {
+    if (Label != NULL) {
+      DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);
+      Die->addValue(Attribute, dwarf::DW_FORM_addr, Value);
+    } else {
+      DIEValue *Value = new (DIEValueAllocator) DIEInteger(0);
+      Die->addValue(Attribute, dwarf::DW_FORM_addr, Value);
+    }
+  } else {
+    unsigned idx = DU->getAddrPoolIndex(Label);
+    DIEValue *Value = new (DIEValueAllocator) DIEInteger(idx);
+    Die->addValue(Attribute, dwarf::DW_FORM_GNU_addr_index, Value);
+  }
+}
+
+/// addOpAddress - Add a dwarf op address data and value using the
+/// form given and an op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
+///
+void CompileUnit::addOpAddress(DIEBlock *Die, const MCSymbol *Sym) {
+  DD->addArangeLabel(SymbolCU(this, Sym));
+  if (!DD->useSplitDwarf()) {
+    addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);
+    addLabel(Die, dwarf::DW_FORM_udata, Sym);
+  } else {
+    addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_addr_index);
+    addUInt(Die, dwarf::DW_FORM_GNU_addr_index, DU->getAddrPoolIndex(Sym));
+  }
+}
+
+/// addDelta - Add a label delta attribute data and value.
+///
+void CompileUnit::addDelta(DIE *Die, dwarf::Attribute Attribute,
+                           dwarf::Form Form, const MCSymbol *Hi,
+                           const MCSymbol *Lo) {
+  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
+  Die->addValue(Attribute, Form, Value);
+}
+
+/// addDIEEntry - Add a DIE attribute data and value.
+///
+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->getCompileUnitOrNull();
+  const DIE *EntryCU = Entry->getEntry()->getCompileUnitOrNull();
+  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, DIDescriptor N) {
+  DIE *Die = new DIE(Tag);
+  Parent.addChild(Die);
+  if (N)
+    insertDIE(N, Die);
+  return Die;
+}
+
+/// addBlock - Add block data.
+///
+void CompileUnit::addBlock(DIE *Die, dwarf::Attribute Attribute,
+                           DIEBlock *Block) {
+  Block->ComputeSize(Asm);
+  DIEBlocks.push_back(Block); // Memoize so we can call the destructor later on.
+  Die->addValue(Attribute, Block->BestForm(), Block);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DIVariable V) {
+  // Verify variable.
+  if (!V.isVariable())
+    return;
+
+  unsigned Line = V.getLineNumber();
+  if (Line == 0)
+    return;
+  unsigned FileID =
+      DD->getOrCreateSourceID(V.getContext().getFilename(),
+                              V.getContext().getDirectory(), getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DIGlobalVariable G) {
+  // Verify global variable.
+  if (!G.isGlobalVariable())
+    return;
+
+  unsigned Line = G.getLineNumber();
+  if (Line == 0)
+    return;
+  unsigned FileID =
+      DD->getOrCreateSourceID(G.getFilename(), G.getDirectory(), getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DISubprogram SP) {
+  // Verify subprogram.
+  if (!SP.isSubprogram())
+    return;
+
+  // If the line number is 0, don't add it.
+  unsigned Line = SP.getLineNumber();
+  if (Line == 0)
+    return;
+
+  unsigned FileID = DD->getOrCreateSourceID(SP.getFilename(), SP.getDirectory(),
+                                            getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DIType Ty) {
+  // Verify type.
+  if (!Ty.isType())
+    return;
+
+  unsigned Line = Ty.getLineNumber();
+  if (Line == 0)
+    return;
+  unsigned FileID = DD->getOrCreateSourceID(Ty.getFilename(), Ty.getDirectory(),
+                                            getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DIObjCProperty Ty) {
+  // Verify type.
+  if (!Ty.isObjCProperty())
+    return;
+
+  unsigned Line = Ty.getLineNumber();
+  if (Line == 0)
+    return;
+  DIFile File = Ty.getFile();
+  unsigned FileID = DD->getOrCreateSourceID(File.getFilename(),
+                                            File.getDirectory(), getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addSourceLine - Add location information to specified debug information
+/// entry.
+void CompileUnit::addSourceLine(DIE *Die, DINameSpace NS) {
+  // Verify namespace.
+  if (!NS.Verify())
+    return;
+
+  unsigned Line = NS.getLineNumber();
+  if (Line == 0)
+    return;
+  StringRef FN = NS.getFilename();
+
+  unsigned FileID =
+      DD->getOrCreateSourceID(FN, NS.getDirectory(), getUniqueID());
+  assert(FileID && "Invalid file id");
+  addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
+  addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
+}
+
+/// addVariableAddress - Add DW_AT_location attribute for a
+/// DbgVariable based on provided MachineLocation.
+void CompileUnit::addVariableAddress(const DbgVariable &DV, DIE *Die,
+                                     MachineLocation Location) {
+  if (DV.variableHasComplexAddress())
+    addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
+  else if (DV.isBlockByrefVariable())
+    addBlockByrefAddress(DV, Die, dwarf::DW_AT_location, Location);
+  else
+    addAddress(Die, dwarf::DW_AT_location, Location,
+               DV.getVariable().isIndirect());
+}
+
+/// addRegisterOp - Add register operand.
+void CompileUnit::addRegisterOp(DIEBlock *TheDie, unsigned Reg) {
+  const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
+  unsigned DWReg = RI->getDwarfRegNum(Reg, false);
+  if (DWReg < 32)
+    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_reg0 + DWReg);
+  else {
+    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_regx);
+    addUInt(TheDie, dwarf::DW_FORM_udata, DWReg);
+  }
+}
+
+/// addRegisterOffset - Add register offset.
+void CompileUnit::addRegisterOffset(DIEBlock *TheDie, unsigned Reg,
+                                    int64_t Offset) {
+  const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
+  unsigned DWReg = RI->getDwarfRegNum(Reg, false);
+  const TargetRegisterInfo *TRI = Asm->TM.getRegisterInfo();
+  if (Reg == TRI->getFrameRegister(*Asm->MF))
+    // If variable offset is based in frame register then use fbreg.
+    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_fbreg);
+  else if (DWReg < 32)
+    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_breg0 + DWReg);
+  else {
+    addUInt(TheDie, dwarf::DW_FORM_data1, dwarf::DW_OP_bregx);
+    addUInt(TheDie, dwarf::DW_FORM_udata, DWReg);
+  }
+  addSInt(TheDie, dwarf::DW_FORM_sdata, Offset);
+}
+
+/// addAddress - Add an address attribute to a die based on the location
+/// provided.
+void CompileUnit::addAddress(DIE *Die, dwarf::Attribute Attribute,
+                             const MachineLocation &Location, bool Indirect) {
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+
+  if (Location.isReg() && !Indirect)
+    addRegisterOp(Block, Location.getReg());
+  else {
+    addRegisterOffset(Block, Location.getReg(), Location.getOffset());
+    if (Indirect && !Location.isReg()) {
+      addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+    }
+  }
+
+  // Now attach the location information to the DIE.
+  addBlock(Die, Attribute, Block);
+}
+
+/// addComplexAddress - Start with the address based on the location provided,
+/// and generate the DWARF information necessary to find the actual variable
+/// given the extra address information encoded in the DIVariable, starting from
+/// the starting location.  Add the DWARF information to the die.
+///
+void CompileUnit::addComplexAddress(const DbgVariable &DV, DIE *Die,
+                                    dwarf::Attribute Attribute,
+                                    const MachineLocation &Location) {
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+  unsigned N = DV.getNumAddrElements();
+  unsigned i = 0;
+  if (Location.isReg()) {
+    if (N >= 2 && DV.getAddrElement(0) == DIBuilder::OpPlus) {
+      // If first address element is OpPlus then emit
+      // DW_OP_breg + Offset instead of DW_OP_reg + Offset.
+      addRegisterOffset(Block, Location.getReg(), DV.getAddrElement(1));
+      i = 2;
+    } else
+      addRegisterOp(Block, Location.getReg());
+  } else
+    addRegisterOffset(Block, Location.getReg(), Location.getOffset());
+
+  for (; i < N; ++i) {
+    uint64_t Element = DV.getAddrElement(i);
+    if (Element == DIBuilder::OpPlus) {
+      addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
+      addUInt(Block, dwarf::DW_FORM_udata, DV.getAddrElement(++i));
+    } else if (Element == DIBuilder::OpDeref) {
+      if (!Location.isReg())
+        addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+    } else
+      llvm_unreachable("unknown DIBuilder Opcode");
+  }
+
+  // Now attach the location information to the DIE.
+  addBlock(Die, Attribute, Block);
+}
+
+/* Byref variables, in Blocks, are declared by the programmer as "SomeType
+   VarName;", but the compiler creates a __Block_byref_x_VarName struct, and
+   gives the variable VarName either the struct, or a pointer to the struct, as
+   its type.  This is necessary for various behind-the-scenes things the
+   compiler needs to do with by-reference variables in Blocks.
+
+   However, as far as the original *programmer* is concerned, the variable
+   should still have type 'SomeType', as originally declared.
+
+   The function getBlockByrefType dives into the __Block_byref_x_VarName
+   struct to find the original type of the variable, which is then assigned to
+   the variable's Debug Information Entry as its real type.  So far, so good.
+   However now the debugger will expect the variable VarName to have the type
+   SomeType.  So we need the location attribute for the variable to be an
+   expression that explains to the debugger how to navigate through the
+   pointers and struct to find the actual variable of type SomeType.
+
+   The following function does just that.  We start by getting
+   the "normal" location for the variable. This will be the location
+   of either the struct __Block_byref_x_VarName or the pointer to the
+   struct __Block_byref_x_VarName.
+
+   The struct will look something like:
+
+   struct __Block_byref_x_VarName {
+     ... <various fields>
+     struct __Block_byref_x_VarName *forwarding;
+     ... <various other fields>
+     SomeType VarName;
+     ... <maybe more fields>
+   };
+
+   If we are given the struct directly (as our starting point) we
+   need to tell the debugger to:
+
+   1).  Add the offset of the forwarding field.
+
+   2).  Follow that pointer to get the real __Block_byref_x_VarName
+   struct to use (the real one may have been copied onto the heap).
+
+   3).  Add the offset for the field VarName, to find the actual variable.
+
+   If we started with a pointer to the struct, then we need to
+   dereference that pointer first, before the other steps.
+   Translating this into DWARF ops, we will need to append the following
+   to the current location description for the variable:
+
+   DW_OP_deref                    -- optional, if we start with a pointer
+   DW_OP_plus_uconst <forward_fld_offset>
+   DW_OP_deref
+   DW_OP_plus_uconst <varName_fld_offset>
+
+   That is what this function does.  */
+
+/// addBlockByrefAddress - Start with the address based on the location
+/// provided, and generate the DWARF information necessary to find the
+/// actual Block variable (navigating the Block struct) based on the
+/// starting location.  Add the DWARF information to the die.  For
+/// more information, read large comment just above here.
+///
+void CompileUnit::addBlockByrefAddress(const DbgVariable &DV, DIE *Die,
+                                       dwarf::Attribute Attribute,
+                                       const MachineLocation &Location) {
+  DIType Ty = DV.getType();
+  DIType TmpTy = Ty;
+  uint16_t Tag = Ty.getTag();
+  bool isPointer = false;
+
+  StringRef varName = DV.getName();
+
+  if (Tag == dwarf::DW_TAG_pointer_type) {
+    DIDerivedType DTy(Ty);
+    TmpTy = resolve(DTy.getTypeDerivedFrom());
+    isPointer = true;
+  }
+
+  DICompositeType blockStruct(TmpTy);
+
+  // Find the __forwarding field and the variable field in the __Block_byref
+  // struct.
+  DIArray Fields = blockStruct.getTypeArray();
+  DIDerivedType varField;
+  DIDerivedType forwardingField;
+
+  for (unsigned i = 0, N = Fields.getNumElements(); i < N; ++i) {
+    DIDerivedType DT(Fields.getElement(i));
+    StringRef fieldName = DT.getName();
+    if (fieldName == "__forwarding")
+      forwardingField = DT;
+    else if (fieldName == varName)
+      varField = DT;
+  }
+
+  // Get the offsets for the forwarding field and the variable field.
+  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.
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+
+  if (Location.isReg())
+    addRegisterOp(Block, Location.getReg());
+  else
+    addRegisterOffset(Block, Location.getReg(), Location.getOffset());
+
+  // If we started with a pointer to the __Block_byref... struct, then
+  // the first thing we need to do is dereference the pointer (DW_OP_deref).
+  if (isPointer)
+    addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+
+  // Next add the offset for the '__forwarding' field:
+  // DW_OP_plus_uconst ForwardingFieldOffset.  Note there's no point in
+  // adding the offset if it's 0.
+  if (forwardingFieldOffset > 0) {
+    addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
+    addUInt(Block, dwarf::DW_FORM_udata, forwardingFieldOffset);
+  }
+
+  // Now dereference the __forwarding field to get to the real __Block_byref
+  // struct:  DW_OP_deref.
+  addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+
+  // Now that we've got the real __Block_byref... struct, add the offset
+  // for the variable's field to get to the location of the actual variable:
+  // DW_OP_plus_uconst varFieldOffset.  Again, don't add if it's 0.
+  if (varFieldOffset > 0) {
+    addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
+    addUInt(Block, dwarf::DW_FORM_udata, varFieldOffset);
+  }
+
+  // Now attach the location information to the DIE.
+  addBlock(Die, Attribute, Block);
+}
+
+/// isTypeSigned - Return true if the type is signed.
+static bool isTypeSigned(DwarfDebug *DD, DIType Ty, int *SizeInBits) {
+  if (Ty.isDerivedType())
+    return isTypeSigned(DD, DD->resolve(DIDerivedType(Ty).getTypeDerivedFrom()),
+                        SizeInBits);
+  if (Ty.isBasicType())
+    if (DIBasicType(Ty).getEncoding() == dwarf::DW_ATE_signed ||
+        DIBasicType(Ty).getEncoding() == dwarf::DW_ATE_signed_char) {
+      *SizeInBits = Ty.getSizeInBits();
+      return true;
+    }
+  return false;
+}
+
+/// Return true if type encoding is unsigned.
+static bool isUnsignedDIType(DwarfDebug *DD, DIType Ty) {
+  DIDerivedType DTy(Ty);
+  if (DTy.isDerivedType())
+    return isUnsignedDIType(DD, DD->resolve(DTy.getTypeDerivedFrom()));
+
+  DIBasicType BTy(Ty);
+  if (BTy.isBasicType()) {
+    unsigned Encoding = BTy.getEncoding();
+    if (Encoding == dwarf::DW_ATE_unsigned ||
+        Encoding == dwarf::DW_ATE_unsigned_char ||
+        Encoding == dwarf::DW_ATE_boolean)
+      return true;
+  }
+  return false;
+}
+
+/// If this type is derived from a base type then return base type size.
+static uint64_t getBaseTypeSize(DwarfDebug *DD, DIDerivedType Ty) {
+  unsigned Tag = Ty.getTag();
+
+  if (Tag != dwarf::DW_TAG_member && Tag != dwarf::DW_TAG_typedef &&
+      Tag != dwarf::DW_TAG_const_type && Tag != dwarf::DW_TAG_volatile_type &&
+      Tag != dwarf::DW_TAG_restrict_type)
+    return Ty.getSizeInBits();
+
+  DIType BaseType = DD->resolve(Ty.getTypeDerivedFrom());
+
+  // If this type is not derived from any type then take conservative approach.
+  if (!BaseType.isValid())
+    return Ty.getSizeInBits();
+
+  // If this is a derived type, go ahead and get the base type, unless it's a
+  // reference then it's just the size of the field. Pointer types have no need
+  // of this since they're a different type of qualification on the type.
+  if (BaseType.getTag() == dwarf::DW_TAG_reference_type ||
+      BaseType.getTag() == dwarf::DW_TAG_rvalue_reference_type)
+    return Ty.getSizeInBits();
+
+  if (BaseType.isDerivedType())
+    return getBaseTypeSize(DD, DIDerivedType(BaseType));
+
+  return BaseType.getSizeInBits();
+}
+
+/// addConstantValue - Add constant value entry in variable DIE.
+void CompileUnit::addConstantValue(DIE *Die, const MachineOperand &MO,
+                                   DIType Ty) {
+  // FIXME: This is a bit conservative/simple - it emits negative values at
+  // their maximum bit width which is a bit unfortunate (& doesn't prefer
+  // udata/sdata over dataN as suggested by the DWARF spec)
+  assert(MO.isImm() && "Invalid machine operand!");
+  int SizeInBits = -1;
+  bool SignedConstant = isTypeSigned(DD, Ty, &SizeInBits);
+  dwarf::Form Form;
+
+  // If we're a signed constant definitely use sdata.
+  if (SignedConstant) {
+    addSInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata, MO.getImm());
+    return;
+  }
+
+  // Else use data for now unless it's larger than we can deal with.
+  switch (SizeInBits) {
+  case 8:
+    Form = dwarf::DW_FORM_data1;
+    break;
+  case 16:
+    Form = dwarf::DW_FORM_data2;
+    break;
+  case 32:
+    Form = dwarf::DW_FORM_data4;
+    break;
+  case 64:
+    Form = dwarf::DW_FORM_data8;
+    break;
+  default:
+    Form = dwarf::DW_FORM_udata;
+    addUInt(Die, dwarf::DW_AT_const_value, Form, MO.getImm());
+    return;
+  }
+  addUInt(Die, dwarf::DW_AT_const_value, Form, MO.getImm());
+}
+
+/// addConstantFPValue - Add constant value entry in variable DIE.
+void CompileUnit::addConstantFPValue(DIE *Die, const MachineOperand &MO) {
+  assert(MO.isFPImm() && "Invalid machine operand!");
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+  APFloat FPImm = MO.getFPImm()->getValueAPF();
+
+  // Get the raw data form of the floating point.
+  const APInt FltVal = FPImm.bitcastToAPInt();
+  const char *FltPtr = (const char *)FltVal.getRawData();
+
+  int NumBytes = FltVal.getBitWidth() / 8; // 8 bits per byte.
+  bool LittleEndian = Asm->getDataLayout().isLittleEndian();
+  int Incr = (LittleEndian ? 1 : -1);
+  int Start = (LittleEndian ? 0 : NumBytes - 1);
+  int Stop = (LittleEndian ? NumBytes : -1);
+
+  // 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]);
+
+  addBlock(Die, dwarf::DW_AT_const_value, Block);
+}
+
+/// addConstantFPValue - Add constant value entry in variable DIE.
+void CompileUnit::addConstantFPValue(DIE *Die, const ConstantFP *CFP) {
+  // Pass this down to addConstantValue as an unsigned bag of bits.
+  addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), true);
+}
+
+/// addConstantValue - Add constant value entry in variable DIE.
+void CompileUnit::addConstantValue(DIE *Die, const ConstantInt *CI,
+                                   bool Unsigned) {
+  addConstantValue(Die, CI->getValue(), Unsigned);
+}
+
+// addConstantValue - Add constant value entry in variable DIE.
+void CompileUnit::addConstantValue(DIE *Die, const APInt &Val, bool Unsigned) {
+  unsigned CIBitWidth = Val.getBitWidth();
+  if (CIBitWidth <= 64) {
+    // If we're a signed constant definitely use sdata.
+    if (!Unsigned) {
+      addSInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_sdata,
+              Val.getSExtValue());
+      return;
+    }
+
+    // Else use data for now unless it's larger than we can deal with.
+    dwarf::Form Form;
+    switch (CIBitWidth) {
+    case 8:
+      Form = dwarf::DW_FORM_data1;
+      break;
+    case 16:
+      Form = dwarf::DW_FORM_data2;
+      break;
+    case 32:
+      Form = dwarf::DW_FORM_data4;
+      break;
+    case 64:
+      Form = dwarf::DW_FORM_data8;
+      break;
+    default:
+      addUInt(Die, dwarf::DW_AT_const_value, dwarf::DW_FORM_udata,
+              Val.getZExtValue());
+      return;
+    }
+    addUInt(Die, dwarf::DW_AT_const_value, Form, Val.getZExtValue());
+    return;
+  }
+
+  DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+
+  // Get the raw data form of the large APInt.
+  const uint64_t *Ptr64 = Val.getRawData();
+
+  int NumBytes = Val.getBitWidth() / 8; // 8 bits per byte.
+  bool LittleEndian = Asm->getDataLayout().isLittleEndian();
+
+  // Output the constant to DWARF one byte at a time.
+  for (int i = 0; i < NumBytes; i++) {
+    uint8_t c;
+    if (LittleEndian)
+      c = Ptr64[i / 8] >> (8 * (i & 7));
+    else
+      c = Ptr64[(NumBytes - 1 - i) / 8] >> (8 * ((NumBytes - 1 - i) & 7));
+    addUInt(Block, dwarf::DW_FORM_data1, c);
+  }
+
+  addBlock(Die, dwarf::DW_AT_const_value, Block);
+}
+
+/// addTemplateParams - Add template parameters into buffer.
+void CompileUnit::addTemplateParams(DIE &Buffer, DIArray TParams) {
+  // Add template parameters.
+  for (unsigned i = 0, e = TParams.getNumElements(); i != e; ++i) {
+    DIDescriptor Element = TParams.getElement(i);
+    if (Element.isTemplateTypeParameter())
+      constructTemplateTypeParameterDIE(Buffer,
+                                        DITemplateTypeParameter(Element));
+    else if (Element.isTemplateValueParameter())
+      constructTemplateValueParameterDIE(Buffer,
+                                         DITemplateValueParameter(Element));
+  }
+}
+
+/// getOrCreateContextDIE - Get context owner's DIE.
+DIE *CompileUnit::getOrCreateContextDIE(DIScope Context) {
+  if (!Context || Context.isFile())
+    return getCUDie();
+  if (Context.isType())
+    return getOrCreateTypeDIE(DIType(Context));
+  if (Context.isNameSpace())
+    return getOrCreateNameSpace(DINameSpace(Context));
+  if (Context.isSubprogram())
+    return getOrCreateSubprogramDIE(DISubprogram(Context));
+  return getDIE(Context);
+}
+
+/// getOrCreateTypeDIE - Find existing DIE or create new DIE for the
+/// given DIType.
+DIE *CompileUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
+  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()));
+  assert(ContextDIE);
+
+  DIE *TyDIE = getDIE(Ty);
+  if (TyDIE)
+    return TyDIE;
+
+  // Create new type.
+  TyDIE = createAndAddDIE(Ty.getTag(), *ContextDIE, Ty);
+
+  if (Ty.isBasicType())
+    constructTypeDIE(*TyDIE, DIBasicType(Ty));
+  else if (Ty.isCompositeType())
+    constructTypeDIE(*TyDIE, DICompositeType(Ty));
+  else {
+    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.
+  if (!Ty.getName().empty() && !Ty.isForwardDecl()) {
+    bool IsImplementation = 0;
+    if (Ty.isCompositeType()) {
+      DICompositeType CT(Ty);
+      // A runtime language of 0 actually means C/C++ and that any
+      // non-negative value is some version of Objective-C/C++.
+      IsImplementation = (CT.getRunTimeLang() == 0) || CT.isObjcClassComplete();
+    }
+    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.
+void CompileUnit::addType(DIE *Entity, DIType Ty, dwarf::Attribute Attribute) {
+  assert(Ty && "Trying to add a type that doesn't exist?");
+
+  // 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);
+
+  // If this is a complete composite type then include it in the
+  // list of global types.
+  addGlobalType(Ty);
+}
+
+// Accelerator table mutators - add each name along with its companion
+// 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) {
+  DU->getStringPoolEntry(Name);
+  std::vector<DIE *> &DIEs = AccelNames[Name];
+  DIEs.push_back(Die);
+}
+
+void CompileUnit::addAccelObjC(StringRef Name, DIE *Die) {
+  DU->getStringPoolEntry(Name);
+  std::vector<DIE *> &DIEs = AccelObjC[Name];
+  DIEs.push_back(Die);
+}
+
+void CompileUnit::addAccelNamespace(StringRef Name, DIE *Die) {
+  DU->getStringPoolEntry(Name);
+  std::vector<DIE *> &DIEs = AccelNamespace[Name];
+  DIEs.push_back(Die);
+}
+
+void CompileUnit::addAccelType(StringRef Name, std::pair<DIE *, unsigned> Die) {
+  DU->getStringPoolEntry(Name);
+  std::vector<std::pair<DIE *, unsigned> > &DIEs = AccelTypes[Name];
+  DIEs.push_back(Die);
+}
+
+/// addGlobalName - Add a new global name to the compile unit.
+void CompileUnit::addGlobalName(StringRef Name, DIE *Die, DIScope Context) {
+  std::string FullName = getParentContextString(Context) + Name.str();
+  GlobalNames[FullName] = Die;
+}
+
+/// addGlobalType - Add a new global type to the compile unit.
+///
+void CompileUnit::addGlobalType(DIType Ty) {
+  DIScope Context = resolve(Ty.getContext());
+  if (!Ty.getName().empty() && !Ty.isForwardDecl() &&
+      (!Context || Context.isCompileUnit() || Context.isFile() ||
+       Context.isNameSpace()))
+    if (DIEEntry *Entry = getDIEEntry(Ty)) {
+      std::string FullName =
+          getParentContextString(Context) + Ty.getName().str();
+      GlobalTypes[FullName] = Entry->getEntry();
+    }
+}
+
+/// getParentContextString - Walks the metadata parent chain in a language
+/// specific manner (using the compile unit language) and returns
+/// it as a string. This is done at the metadata level because DIEs may
+/// not currently have been added to the parent context and walking the
+/// DIEs looking for names is more expensive than walking the metadata.
+std::string CompileUnit::getParentContextString(DIScope Context) const {
+  if (!Context)
+    return "";
+
+  // FIXME: Decide whether to implement this for non-C++ languages.
+  if (getLanguage() != dwarf::DW_LANG_C_plus_plus)
+    return "";
+
+  std::string CS;
+  SmallVector<DIScope, 1> Parents;
+  while (!Context.isCompileUnit()) {
+    Parents.push_back(Context);
+    if (Context.getContext())
+      Context = resolve(Context.getContext());
+    else
+      // Structure, etc types will have a NULL context if they're at the top
+      // level.
+      break;
+  }
+
+  // Reverse iterate over our list to go from the outermost construct to the
+  // innermost.
+  for (SmallVectorImpl<DIScope>::reverse_iterator I = Parents.rbegin(),
+                                                  E = Parents.rend();
+       I != E; ++I) {
+    DIScope Ctx = *I;
+    StringRef Name = Ctx.getName();
+    if (!Name.empty()) {
+      CS += Name;
+      CS += "::";
+    }
+  }
+  return CS;
+}
+
+/// addPubTypes - Add subprogram argument types for pubtypes section.
+void CompileUnit::addPubTypes(DISubprogram SP) {
+  DICompositeType SPTy = SP.getType();
+  uint16_t SPTag = SPTy.getTag();
+  if (SPTag != dwarf::DW_TAG_subroutine_type)
+    return;
+
+  DIArray Args = SPTy.getTypeArray();
+  for (unsigned i = 0, e = Args.getNumElements(); i != e; ++i) {
+    DIType ATy(Args.getElement(i));
+    if (!ATy.isType())
+      continue;
+    addGlobalType(ATy);
+  }
+}
+
+/// constructTypeDIE - Construct basic type die from DIBasicType.
+void CompileUnit::constructTypeDIE(DIE &Buffer, DIBasicType BTy) {
+  // Get core information.
+  StringRef Name = BTy.getName();
+  // Add name if not anonymous or intermediate type.
+  if (!Name.empty())
+    addString(&Buffer, dwarf::DW_AT_name, Name);
+
+  // An unspecified type only has a name attribute.
+  if (BTy.getTag() == dwarf::DW_TAG_unspecified_type)
+    return;
+
+  addUInt(&Buffer, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
+          BTy.getEncoding());
+
+  uint64_t Size = BTy.getSizeInBits() >> 3;
+  addUInt(&Buffer, dwarf::DW_AT_byte_size, None, Size);
+}
+
+/// constructTypeDIE - Construct derived type die from DIDerivedType.
+void CompileUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) {
+  // Get core information.
+  StringRef Name = DTy.getName();
+  uint64_t Size = DTy.getSizeInBits() >> 3;
+  uint16_t Tag = Buffer.getTag();
+
+  // Map to main type, void will not have a type.
+  DIType FromTy = resolve(DTy.getTypeDerivedFrom());
+  if (FromTy)
+    addType(&Buffer, FromTy);
+
+  // Add name if not anonymous or intermediate type.
+  if (!Name.empty())
+    addString(&Buffer, dwarf::DW_AT_name, Name);
+
+  // Add size if non-zero (derived types might be zero-sized.)
+  if (Size && Tag != dwarf::DW_TAG_pointer_type)
+    addUInt(&Buffer, dwarf::DW_AT_byte_size, None, Size);
+
+  if (Tag == dwarf::DW_TAG_ptr_to_member_type)
+    addDIEEntry(&Buffer, dwarf::DW_AT_containing_type,
+                getOrCreateTypeDIE(resolve(DTy.getClassType())));
+  // Add source line info if available and TyDesc is not a forward declaration.
+  if (!DTy.isForwardDecl())
+    addSourceLine(&Buffer, DTy);
+}
+
+/// Return true if the type is appropriately scoped to be contained inside
+/// its own type unit.
+static bool isTypeUnitScoped(DIType Ty, const DwarfDebug *DD) {
+  DIScope Parent = DD->resolve(Ty.getContext());
+  while (Parent) {
+    // Don't generate a hash for anything scoped inside a function.
+    if (Parent.isSubprogram())
+      return false;
+    Parent = DD->resolve(Parent.getContext());
+  }
+  return true;
+}
+
+/// Return true if the type should be split out into a type unit.
+static bool shouldCreateTypeUnit(DICompositeType CTy, const DwarfDebug *DD) {
+  uint16_t Tag = CTy.getTag();
+
+  switch (Tag) {
+  case dwarf::DW_TAG_structure_type:
+  case dwarf::DW_TAG_union_type:
+  case dwarf::DW_TAG_enumeration_type:
+  case dwarf::DW_TAG_class_type:
+    // If this is a class, structure, union, or enumeration type
+    // that is a definition (not a declaration), and not scoped
+    // inside a function then separate this out as a type unit.
+    return !CTy.isForwardDecl() && isTypeUnitScoped(CTy, DD);
+  default:
+    return false;
+  }
+}
+
+/// constructTypeDIE - Construct type DIE from DICompositeType.
+void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
+  // Get core information.
+  StringRef Name = CTy.getName();
+
+  uint64_t Size = CTy.getSizeInBits() >> 3;
+  uint16_t Tag = Buffer.getTag();
+
+  switch (Tag) {
+  case dwarf::DW_TAG_array_type:
+    constructArrayTypeDIE(Buffer, CTy);
+    break;
+  case dwarf::DW_TAG_enumeration_type:
+    constructEnumTypeDIE(Buffer, CTy);
+    break;
+  case dwarf::DW_TAG_subroutine_type: {
+    // Add return type. A void return won't have a type.
+    DIArray Elements = CTy.getTypeArray();
+    DIType RTy(Elements.getElement(0));
+    if (RTy)
+      addType(&Buffer, RTy);
+
+    bool isPrototyped = true;
+    // Add arguments.
+    for (unsigned i = 1, N = Elements.getNumElements(); i < N; ++i) {
+      DIDescriptor Ty = Elements.getElement(i);
+      if (Ty.isUnspecifiedParameter()) {
+        createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
+        isPrototyped = false;
+      } else {
+        DIE *Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, Buffer);
+        addType(Arg, DIType(Ty));
+        if (DIType(Ty).isArtificial())
+          addFlag(Arg, dwarf::DW_AT_artificial);
+      }
+    }
+    // Add prototype flag if we're dealing with a C language and the
+    // function has been prototyped.
+    uint16_t Language = getLanguage();
+    if (isPrototyped &&
+        (Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
+         Language == dwarf::DW_LANG_ObjC))
+      addFlag(&Buffer, dwarf::DW_AT_prototyped);
+  } break;
+  case dwarf::DW_TAG_structure_type:
+  case dwarf::DW_TAG_union_type:
+  case dwarf::DW_TAG_class_type: {
+    // Add elements to structure type.
+    DIArray Elements = CTy.getTypeArray();
+    for (unsigned i = 0, N = Elements.getNumElements(); i < N; ++i) {
+      DIDescriptor Element = Elements.getElement(i);
+      DIE *ElemDie = NULL;
+      if (Element.isSubprogram()) {
+        DISubprogram SP(Element);
+        ElemDie = getOrCreateSubprogramDIE(SP);
+        if (SP.isProtected())
+          addUInt(ElemDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+                  dwarf::DW_ACCESS_protected);
+        else if (SP.isPrivate())
+          addUInt(ElemDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+                  dwarf::DW_ACCESS_private);
+        else
+          addUInt(ElemDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+                  dwarf::DW_ACCESS_public);
+        if (SP.isExplicit())
+          addFlag(ElemDie, dwarf::DW_AT_explicit);
+      } else if (Element.isDerivedType()) {
+        DIDerivedType DDTy(Element);
+        if (DDTy.getTag() == dwarf::DW_TAG_friend) {
+          ElemDie = createAndAddDIE(dwarf::DW_TAG_friend, Buffer);
+          addType(ElemDie, resolve(DDTy.getTypeDerivedFrom()),
+                  dwarf::DW_AT_friend);
+        } else if (DDTy.isStaticMember()) {
+          getOrCreateStaticMemberDIE(DDTy);
+        } else {
+          constructMemberDIE(Buffer, DDTy);
+        }
+      } else if (Element.isObjCProperty()) {
+        DIObjCProperty Property(Element);
+        ElemDie = createAndAddDIE(Property.getTag(), Buffer);
+        StringRef PropertyName = Property.getObjCPropertyName();
+        addString(ElemDie, dwarf::DW_AT_APPLE_property_name, PropertyName);
+        addType(ElemDie, Property.getType());
+        addSourceLine(ElemDie, Property);
+        StringRef GetterName = Property.getObjCPropertyGetterName();
+        if (!GetterName.empty())
+          addString(ElemDie, dwarf::DW_AT_APPLE_property_getter, GetterName);
+        StringRef SetterName = Property.getObjCPropertySetterName();
+        if (!SetterName.empty())
+          addString(ElemDie, dwarf::DW_AT_APPLE_property_setter, SetterName);
+        unsigned PropertyAttributes = 0;
+        if (Property.isReadOnlyObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_readonly;
+        if (Property.isReadWriteObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_readwrite;
+        if (Property.isAssignObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_assign;
+        if (Property.isRetainObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_retain;
+        if (Property.isCopyObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_copy;
+        if (Property.isNonAtomicObjCProperty())
+          PropertyAttributes |= dwarf::DW_APPLE_PROPERTY_nonatomic;
+        if (PropertyAttributes)
+          addUInt(ElemDie, dwarf::DW_AT_APPLE_property_attribute, None,
+                  PropertyAttributes);
+
+        DIEEntry *Entry = getDIEEntry(Element);
+        if (!Entry) {
+          Entry = createDIEEntry(ElemDie);
+          insertDIEEntry(Element, Entry);
+        }
+      } else
+        continue;
+    }
+
+    if (CTy.isAppleBlockExtension())
+      addFlag(&Buffer, dwarf::DW_AT_APPLE_block);
+
+    DICompositeType ContainingType(resolve(CTy.getContainingType()));
+    if (ContainingType)
+      addDIEEntry(&Buffer, dwarf::DW_AT_containing_type,
+                  getOrCreateTypeDIE(ContainingType));
+
+    if (CTy.isObjcClassComplete())
+      addFlag(&Buffer, dwarf::DW_AT_APPLE_objc_complete_type);
+
+    // Add template parameters to a class, structure or union types.
+    // FIXME: The support isn't in the metadata for this yet.
+    if (Tag == dwarf::DW_TAG_class_type ||
+        Tag == dwarf::DW_TAG_structure_type || Tag == dwarf::DW_TAG_union_type)
+      addTemplateParams(Buffer, CTy.getTemplateParams());
+
+    break;
+  }
+  default:
+    break;
+  }
+
+  // Add name if not anonymous or intermediate type.
+  if (!Name.empty())
+    addString(&Buffer, dwarf::DW_AT_name, Name);
+
+  if (Tag == dwarf::DW_TAG_enumeration_type ||
+      Tag == dwarf::DW_TAG_class_type || Tag == dwarf::DW_TAG_structure_type ||
+      Tag == dwarf::DW_TAG_union_type) {
+    // Add size if non-zero (derived types might be zero-sized.)
+    // TODO: Do we care about size for enum forward declarations?
+    if (Size)
+      addUInt(&Buffer, dwarf::DW_AT_byte_size, None, Size);
+    else if (!CTy.isForwardDecl())
+      // Add zero size if it is not a forward declaration.
+      addUInt(&Buffer, dwarf::DW_AT_byte_size, None, 0);
+
+    // If we're a forward decl, say so.
+    if (CTy.isForwardDecl())
+      addFlag(&Buffer, dwarf::DW_AT_declaration);
+
+    // Add source line info if available.
+    if (!CTy.isForwardDecl())
+      addSourceLine(&Buffer, CTy);
+
+    // No harm in adding the runtime language to the declaration.
+    unsigned RLang = CTy.getRunTimeLang();
+    if (RLang)
+      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
+/// DITemplateTypeParameter.
+void
+CompileUnit::constructTemplateTypeParameterDIE(DIE &Buffer,
+                                               DITemplateTypeParameter TP) {
+  DIE *ParamDIE =
+      createAndAddDIE(dwarf::DW_TAG_template_type_parameter, Buffer);
+  // Add the type if it exists, it could be void and therefore no type.
+  if (TP.getType())
+    addType(ParamDIE, resolve(TP.getType()));
+  if (!TP.getName().empty())
+    addString(ParamDIE, dwarf::DW_AT_name, TP.getName());
+}
+
+/// constructTemplateValueParameterDIE - Construct new DIE for the given
+/// DITemplateValueParameter.
+void
+CompileUnit::constructTemplateValueParameterDIE(DIE &Buffer,
+                                                DITemplateValueParameter VP) {
+  DIE *ParamDIE = createAndAddDIE(VP.getTag(), Buffer);
+
+  // Add the type if there is one, template template and template parameter
+  // packs will not have a type.
+  if (VP.getTag() == dwarf::DW_TAG_template_value_parameter)
+    addType(ParamDIE, resolve(VP.getType()));
+  if (!VP.getName().empty())
+    addString(ParamDIE, dwarf::DW_AT_name, VP.getName());
+  if (Value *Val = VP.getValue()) {
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(Val))
+      addConstantValue(ParamDIE, CI,
+                       isUnsignedDIType(DD, resolve(VP.getType())));
+    else if (GlobalValue *GV = dyn_cast<GlobalValue>(Val)) {
+      // For declaration non-type template parameters (such as global values and
+      // functions)
+      DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+      addOpAddress(Block, 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.
+      addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_stack_value);
+      addBlock(ParamDIE, dwarf::DW_AT_location, Block);
+    } else if (VP.getTag() == dwarf::DW_TAG_GNU_template_template_param) {
+      assert(isa<MDString>(Val));
+      addString(ParamDIE, dwarf::DW_AT_GNU_template_name,
+                cast<MDString>(Val)->getString());
+    } else if (VP.getTag() == dwarf::DW_TAG_GNU_template_parameter_pack) {
+      assert(isa<MDNode>(Val));
+      DIArray A(cast<MDNode>(Val));
+      addTemplateParams(*ParamDIE, A);
+    }
+  }
+}
+
+/// getOrCreateNameSpace - Create a DIE for DINameSpace.
+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());
+
+  DIE *NDie = getDIE(NS);
+  if (NDie)
+    return NDie;
+  NDie = createAndAddDIE(dwarf::DW_TAG_namespace, *ContextDIE, NS);
+
+  if (!NS.getName().empty()) {
+    addString(NDie, dwarf::DW_AT_name, NS.getName());
+    addAccelNamespace(NS.getName(), NDie);
+    addGlobalName(NS.getName(), NDie, NS.getContext());
+  } else
+    addAccelNamespace("(anonymous namespace)", NDie);
+  addSourceLine(NDie, NS);
+  return NDie;
+}
+
+/// getOrCreateSubprogramDIE - Create new DIE using SP.
+DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
+  // Construct the context before querying for the existence of the DIE in case
+  // such construction creates the DIE (as is the case for member function
+  // declarations).
+  DIE *ContextDIE = getOrCreateContextDIE(resolve(SP.getContext()));
+
+  DIE *SPDie = getDIE(SP);
+  if (SPDie)
+    return SPDie;
+
+  DISubprogram SPDecl = SP.getFunctionDeclaration();
+  if (SPDecl.isSubprogram())
+    // Add subprogram definitions to the CU die directly.
+    ContextDIE = CUDie.get();
+
+  // DW_TAG_inlined_subroutine may refer to this DIE.
+  SPDie = createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, SP);
+
+  DIE *DeclDie = NULL;
+  if (SPDecl.isSubprogram())
+    DeclDie = getOrCreateSubprogramDIE(SPDecl);
+
+  // Add function template parameters.
+  addTemplateParams(*SPDie, SP.getTemplateParams());
+
+  // If this DIE is going to refer declaration info using AT_specification
+  // then there is no need to add other attributes.
+  if (DeclDie) {
+    // Refer function declaration directly.
+    addDIEEntry(SPDie, dwarf::DW_AT_specification, DeclDie);
+
+    return SPDie;
+  }
+
+  // Add the linkage name if we have one.
+  StringRef LinkageName = SP.getLinkageName();
+  if (!LinkageName.empty())
+    addString(SPDie, dwarf::DW_AT_MIPS_linkage_name,
+              GlobalValue::getRealLinkageName(LinkageName));
+
+  // Constructors and operators for anonymous aggregates do not have names.
+  if (!SP.getName().empty())
+    addString(SPDie, dwarf::DW_AT_name, SP.getName());
+
+  addSourceLine(SPDie, SP);
+
+  // Add the prototype if we have a prototype and we have a C like
+  // language.
+  uint16_t Language = getLanguage();
+  if (SP.isPrototyped() &&
+      (Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
+       Language == dwarf::DW_LANG_ObjC))
+    addFlag(SPDie, dwarf::DW_AT_prototyped);
+
+  DICompositeType SPTy = SP.getType();
+  assert(SPTy.getTag() == dwarf::DW_TAG_subroutine_type &&
+         "the type of a subprogram should be a subroutine");
+
+  DIArray Args = SPTy.getTypeArray();
+  // Add a return type. If this is a type like a C/C++ void type we don't add a
+  // return type.
+  if (Args.getElement(0))
+    addType(SPDie, DIType(Args.getElement(0)));
+
+  unsigned VK = SP.getVirtuality();
+  if (VK) {
+    addUInt(SPDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1, VK);
+    DIEBlock *Block = getDIEBlock();
+    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())));
+  }
+
+  if (!SP.isDefinition()) {
+    addFlag(SPDie, dwarf::DW_AT_declaration);
+
+    // Add arguments. Do not add arguments for subprogram definition. They will
+    // 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(Args.getElement(i));
+      addType(Arg, ATy);
+      if (ATy.isArtificial())
+        addFlag(Arg, dwarf::DW_AT_artificial);
+    }
+  }
+
+  if (SP.isArtificial())
+    addFlag(SPDie, dwarf::DW_AT_artificial);
+
+  if (!SP.isLocalToUnit())
+    addFlag(SPDie, dwarf::DW_AT_external);
+
+  if (SP.isOptimized())
+    addFlag(SPDie, dwarf::DW_AT_APPLE_optimized);
+
+  if (unsigned isa = Asm->getISAEncoding()) {
+    addUInt(SPDie, dwarf::DW_AT_APPLE_isa, dwarf::DW_FORM_flag, isa);
+  }
+
+  return SPDie;
+}
+
+// Return const expression if value is a GEP to access merged global
+// constant. e.g.
+// i8* getelementptr ({ i8, i8, i8, i8 }* @_MergedGlobals, i32 0, i32 0)
+static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
+  const ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>(V);
+  if (!CE || CE->getNumOperands() != 3 ||
+      CE->getOpcode() != Instruction::GetElementPtr)
+    return NULL;
+
+  // First operand points to a global struct.
+  Value *Ptr = CE->getOperand(0);
+  if (!isa<GlobalValue>(Ptr) ||
+      !isa<StructType>(cast<PointerType>(Ptr->getType())->getElementType()))
+    return NULL;
+
+  // Second operand is zero.
+  const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(CE->getOperand(1));
+  if (!CI || !CI->isZero())
+    return NULL;
+
+  // Third operand is offset.
+  if (!isa<ConstantInt>(CE->getOperand(2)))
+    return NULL;
+
+  return CE;
+}
+
+/// createGlobalVariableDIE - create global variable DIE.
+void CompileUnit::createGlobalVariableDIE(DIGlobalVariable GV) {
+
+  // Check for pre-existence.
+  if (getDIE(GV))
+    return;
+
+  if (!GV.isGlobalVariable())
+    return;
+
+  DIScope GVContext = GV.getContext();
+  DIType GTy = GV.getType();
+
+  // If this is a static data member definition, some attributes belong
+  // to the declaration DIE.
+  DIE *VariableDIE = NULL;
+  bool IsStaticMember = false;
+  DIDerivedType SDMDecl = GV.getStaticDataMemberDeclaration();
+  if (SDMDecl.Verify()) {
+    assert(SDMDecl.isStaticMember() && "Expected static member decl");
+    // We need the declaration DIE that is in the static member's class.
+    VariableDIE = getOrCreateStaticMemberDIE(SDMDecl);
+    IsStaticMember = true;
+  }
+
+  // If this is not a static data member definition, create the variable
+  // DIE and add the initial set of attributes to it.
+  if (!VariableDIE) {
+    // Construct the context before querying for the existence of the DIE in
+    // case such construction creates the DIE.
+    DIE *ContextDIE = getOrCreateContextDIE(GVContext);
+
+    // Add to map.
+    VariableDIE = createAndAddDIE(GV.getTag(), *ContextDIE, GV);
+
+    // Add name and type.
+    addString(VariableDIE, dwarf::DW_AT_name, GV.getDisplayName());
+    addType(VariableDIE, GTy);
+
+    // Add scoping info.
+    if (!GV.isLocalToUnit())
+      addFlag(VariableDIE, dwarf::DW_AT_external);
+
+    // Add line number info.
+    addSourceLine(VariableDIE, GV);
+  }
+
+  // Add location.
+  bool addToAccelTable = false;
+  DIE *VariableSpecDIE = NULL;
+  bool isGlobalVariable = GV.getGlobal() != NULL;
+  if (isGlobalVariable) {
+    addToAccelTable = true;
+    DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+    const MCSymbol *Sym = Asm->getSymbol(GV.getGlobal());
+    if (GV.getGlobal()->isThreadLocal()) {
+      // FIXME: Make this work with -gsplit-dwarf.
+      unsigned PointerSize = Asm->getDataLayout().getPointerSize();
+      assert((PointerSize == 4 || PointerSize == 8) &&
+             "Add support for other sizes if necessary");
+      const MCExpr *Expr =
+          Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym);
+      // Based on GCC's support for TLS:
+      if (!DD->useSplitDwarf()) {
+        // 1) Start with a constNu of the appropriate pointer size
+        addUInt(Block, dwarf::DW_FORM_data1,
+                PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
+        // 2) containing the (relocated) offset of the TLS variable
+        //    within the module's TLS block.
+        addExpr(Block, dwarf::DW_FORM_udata, Expr);
+      } else {
+        addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
+        addUInt(Block, dwarf::DW_FORM_udata, DU->getAddrPoolIndex(Expr));
+      }
+      // 3) followed by a custom OP to make the debugger do a TLS lookup.
+      addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_push_tls_address);
+    } else
+      addOpAddress(Block, Sym);
+    // Do not create specification DIE if context is either compile unit
+    // or a subprogram.
+    if (GVContext && GV.isDefinition() && !GVContext.isCompileUnit() &&
+        !GVContext.isFile() && !DD->isSubprogramContext(GVContext)) {
+      // Create specification DIE.
+      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.
+      if (!SDMDecl.Verify())
+        addFlag(VariableDIE, dwarf::DW_AT_declaration);
+    } else {
+      addBlock(VariableDIE, dwarf::DW_AT_location, Block);
+    }
+    // Add the linkage name.
+    StringRef LinkageName = GV.getLinkageName();
+    if (!LinkageName.empty())
+      // From DWARF4: DIEs to which DW_AT_linkage_name may apply include:
+      // TAG_common_block, TAG_constant, TAG_entry_point, TAG_subprogram and
+      // TAG_variable.
+      addString(IsStaticMember && VariableSpecDIE ? VariableSpecDIE
+                                                  : VariableDIE,
+                dwarf::DW_AT_MIPS_linkage_name,
+                GlobalValue::getRealLinkageName(LinkageName));
+  } else if (const ConstantInt *CI =
+                 dyn_cast_or_null<ConstantInt>(GV.getConstant())) {
+    // AT_const_value was added when the static member was created. To avoid
+    // emitting AT_const_value multiple times, we only add AT_const_value when
+    // it is not a static member.
+    if (!IsStaticMember)
+      addConstantValue(VariableDIE, CI, isUnsignedDIType(DD, GTy));
+  } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV->getOperand(11))) {
+    addToAccelTable = true;
+    // GV is a merged global.
+    DIEBlock *Block = new (DIEValueAllocator) DIEBlock();
+    Value *Ptr = CE->getOperand(0);
+    addOpAddress(Block, Asm->getSymbol(cast<GlobalValue>(Ptr)));
+    addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
+    SmallVector<Value *, 3> Idx(CE->op_begin() + 1, CE->op_end());
+    addUInt(Block, dwarf::DW_FORM_udata,
+            Asm->getDataLayout().getIndexedOffset(Ptr->getType(), Idx));
+    addUInt(Block, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
+    addBlock(VariableDIE, dwarf::DW_AT_location, Block);
+  }
+
+  if (addToAccelTable) {
+    DIE *AddrDIE = VariableSpecDIE ? VariableSpecDIE : VariableDIE;
+    addAccelName(GV.getName(), AddrDIE);
+
+    // If the linkage name is different than the name, go ahead and output
+    // that as well into the name table.
+    if (GV.getLinkageName() != "" && GV.getName() != GV.getLinkageName())
+      addAccelName(GV.getLinkageName(), AddrDIE);
+  }
+
+  if (!GV.isLocalToUnit())
+    addGlobalName(GV.getName(), VariableSpecDIE ? VariableSpecDIE : VariableDIE,
+                  GV.getContext());
+}
+
+/// constructSubrangeDIE - Construct subrange DIE from DISubrange.
+void CompileUnit::constructSubrangeDIE(DIE &Buffer, DISubrange SR,
+                                       DIE *IndexTy) {
+  DIE *DW_Subrange = createAndAddDIE(dwarf::DW_TAG_subrange_type, Buffer);
+  addDIEEntry(DW_Subrange, dwarf::DW_AT_type, IndexTy);
+
+  // The LowerBound value defines the lower bounds which is typically zero for
+  // C/C++. The Count value is the number of elements.  Values are 64 bit. If
+  // Count == -1 then the array is unbounded and we do not emit
+  // DW_AT_lower_bound and DW_AT_upper_bound attributes. If LowerBound == 0 and
+  // Count == 0, then the array has zero elements in which case we do not emit
+  // an upper bound.
+  int64_t LowerBound = SR.getLo();
+  int64_t DefaultLowerBound = getDefaultLowerBound();
+  int64_t Count = SR.getCount();
+
+  if (DefaultLowerBound == -1 || LowerBound != DefaultLowerBound)
+    addUInt(DW_Subrange, dwarf::DW_AT_lower_bound, None, LowerBound);
+
+  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);
+}
+
+/// constructArrayTypeDIE - Construct array type DIE from DICompositeType.
+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()));
+
+  // Get an anonymous type for index type.
+  // FIXME: This type should be passed down from the front end
+  // as different languages may have different sizes for indexes.
+  DIE *IdxTy = getIndexTyDie();
+  if (!IdxTy) {
+    // Construct an anonymous type for index type.
+    IdxTy = createAndAddDIE(dwarf::DW_TAG_base_type, *CUDie.get());
+    addString(IdxTy, dwarf::DW_AT_name, "int");
+    addUInt(IdxTy, dwarf::DW_AT_byte_size, None, sizeof(int32_t));
+    addUInt(IdxTy, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
+            dwarf::DW_ATE_signed);
+    setIndexTyDie(IdxTy);
+  }
+
+  // Add subranges to array type.
+  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)
+      constructSubrangeDIE(Buffer, DISubrange(Element), IdxTy);
+  }
+}
+
+/// 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
+/// vtables.
+void CompileUnit::constructContainingTypeDIEs() {
+  for (DenseMap<DIE *, const MDNode *>::iterator CI = ContainingTypeMap.begin(),
+                                                 CE = ContainingTypeMap.end();
+       CI != CE; ++CI) {
+    DIE *SPDie = CI->first;
+    DIDescriptor D(CI->second);
+    if (!D)
+      continue;
+    DIE *NDie = getDIE(D);
+    if (!NDie)
+      continue;
+    addDIEEntry(SPDie, dwarf::DW_AT_containing_type, NDie);
+  }
+}
+
+/// constructVariableDIE - Construct a DIE for the given DbgVariable.
+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 *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());
+  }
+
+  if (DV.isArtificial())
+    addFlag(VariableDie, dwarf::DW_AT_artificial);
+
+  if (isScopeAbstract) {
+    DV.setDIE(VariableDie);
+    return VariableDie;
+  }
+
+  // Add variable address.
+
+  unsigned Offset = DV.getDotDebugLocOffset();
+  if (Offset != ~0U) {
+    addLabel(VariableDie, dwarf::DW_AT_location,
+             DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+                                        : dwarf::DW_FORM_data4,
+             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()) {
+    assert(DVInsn->getNumOperands() == 3);
+    if (DVInsn->getOperand(0).isReg()) {
+      const MachineOperand RegOp = DVInsn->getOperand(0);
+      // If the second operand is an immediate, this is an indirect value.
+      if (DVInsn->getOperand(1).isImm()) {
+        MachineLocation Location(RegOp.getReg(),
+                                 DVInsn->getOperand(1).getImm());
+        addVariableAddress(DV, VariableDie, Location);
+      } else if (RegOp.getReg())
+        addVariableAddress(DV, VariableDie, MachineLocation(RegOp.getReg()));
+    } else if (DVInsn->getOperand(0).isImm())
+      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()));
+
+    DV.setDIE(VariableDie);
+    return VariableDie;
+  } else {
+    // .. else use frame index.
+    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);
+    }
+  }
+
+  DV.setDIE(VariableDie);
+  return VariableDie;
+}
+
+/// constructMemberDIE - Construct member DIE from DIDerivedType.
+void CompileUnit::constructMemberDIE(DIE &Buffer, DIDerivedType DT) {
+  DIE *MemberDie = createAndAddDIE(DT.getTag(), Buffer);
+  StringRef Name = DT.getName();
+  if (!Name.empty())
+    addString(MemberDie, dwarf::DW_AT_name, Name);
+
+  addType(MemberDie, resolve(DT.getTypeDerivedFrom()));
+
+  addSourceLine(MemberDie, DT);
+
+  DIEBlock *MemLocationDie = new (DIEValueAllocator) DIEBlock();
+  addUInt(MemLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
+
+  if (DT.getTag() == dwarf::DW_TAG_inheritance && DT.isVirtual()) {
+
+    // For C++, virtual base classes are not at fixed offset. Use following
+    // expression to extract appropriate offset from vtable.
+    // BaseAddr = ObAddr + *((*ObAddr) - Offset)
+
+    DIEBlock *VBaseLocationDie = new (DIEValueAllocator) DIEBlock();
+    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);
+    addUInt(VBaseLocationDie, dwarf::DW_FORM_udata, DT.getOffsetInBits());
+    addUInt(VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_minus);
+    addUInt(VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
+    addUInt(VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
+
+    addBlock(MemberDie, dwarf::DW_AT_data_member_location, VBaseLocationDie);
+  } 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,
+            dwarf::DW_ACCESS_protected);
+  else if (DT.isPrivate())
+    addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+            dwarf::DW_ACCESS_private);
+  // Otherwise C++ member and base classes are considered public.
+  else
+    addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+            dwarf::DW_ACCESS_public);
+  if (DT.isVirtual())
+    addUInt(MemberDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1,
+            dwarf::DW_VIRTUALITY_virtual);
+
+  // Objective-C properties.
+  if (MDNode *PNode = DT.getObjCProperty())
+    if (DIEEntry *PropertyDie = getDIEEntry(PNode))
+      MemberDie->addValue(dwarf::DW_AT_APPLE_property, dwarf::DW_FORM_ref4,
+                          PropertyDie);
+
+  if (DT.isArtificial())
+    addFlag(MemberDie, dwarf::DW_AT_artificial);
+}
+
+/// getOrCreateStaticMemberDIE - Create new DIE for C++ static member.
+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(dwarf::isType(ContextDIE->getTag()) &&
+         "Static member should belong to a type.");
+
+  DIE *StaticMemberDIE = getDIE(DT);
+  if (StaticMemberDIE)
+    return StaticMemberDIE;
+
+  StaticMemberDIE = createAndAddDIE(DT.getTag(), *ContextDIE, DT);
+
+  DIType Ty = resolve(DT.getTypeDerivedFrom());
+
+  addString(StaticMemberDIE, dwarf::DW_AT_name, DT.getName());
+  addType(StaticMemberDIE, Ty);
+  addSourceLine(StaticMemberDIE, DT);
+  addFlag(StaticMemberDIE, dwarf::DW_AT_external);
+  addFlag(StaticMemberDIE, dwarf::DW_AT_declaration);
+
+  // FIXME: We could omit private if the parent is a class_type, and
+  // public if the parent is something else.
+  if (DT.isProtected())
+    addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+            dwarf::DW_ACCESS_protected);
+  else if (DT.isPrivate())
+    addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+            dwarf::DW_ACCESS_private);
+  else
+    addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
+            dwarf::DW_ACCESS_public);
+
+  if (const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(DT.getConstant()))
+    addConstantValue(StaticMemberDIE, CI, isUnsignedDIType(DD, Ty));
+  if (const ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(DT.getConstant()))
+    addConstantFPValue(StaticMemberDIE, CFP);
+
+  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());
+}