Update aosp/master LLVM for rebase to r222494.

Change-Id: Ic787f5e0124df789bd26f3f24680f45e678eef2d

27 files changed, 685 insertions, 304 deletions

diff --git a/lib/DebugInfo/Android.mk b/lib/DebugInfo/Android.mk
index 12dfb3b..e777e9c 100644
--- a/lib/DebugInfo/Android.mk
+++ b/lib/DebugInfo/Android.mk
@@ -3,6 +3,7 @@ LOCAL_PATH:= $(call my-dir)
 debuginfo_SRC_FILES := \
   DIContext.cpp \
   DWARFAbbreviationDeclaration.cpp \
+  DWARFAcceleratorTable.cpp \
   DWARFCompileUnit.cpp \
   DWARFContext.cpp \
   DWARFDebugAbbrev.cpp \
diff --git a/lib/DebugInfo/CMakeLists.txt b/lib/DebugInfo/CMakeLists.txt
index 61a3fb0..81fc84d 100644
--- a/lib/DebugInfo/CMakeLists.txt
+++ b/lib/DebugInfo/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_llvm_library(LLVMDebugInfo
   DIContext.cpp
   DWARFAbbreviationDeclaration.cpp
+  DWARFAcceleratorTable.cpp
   DWARFCompileUnit.cpp
   DWARFContext.cpp
   DWARFDebugAbbrev.cpp
diff --git a/lib/DebugInfo/DIContext.cpp b/lib/DebugInfo/DIContext.cpp
index 49a4409..01aecf8 100644
--- a/lib/DebugInfo/DIContext.cpp
+++ b/lib/DebugInfo/DIContext.cpp
@@ -13,6 +13,6 @@ using namespace llvm;
 
 DIContext::~DIContext() {}
 
-DIContext *DIContext::getDWARFContext(object::ObjectFile *Obj) {
+DIContext *DIContext::getDWARFContext(const object::ObjectFile &Obj) {
   return new DWARFContextInMemory(Obj);
 }
diff --git a/lib/DebugInfo/DWARFAbbreviationDeclaration.h b/lib/DebugInfo/DWARFAbbreviationDeclaration.h
index b86b9ec..bb05c30 100644
--- a/lib/DebugInfo/DWARFAbbreviationDeclaration.h
+++ b/lib/DebugInfo/DWARFAbbreviationDeclaration.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
-#define LLVM_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
+#define LLVM_LIB_DEBUGINFO_DWARFABBREVIATIONDECLARATION_H
 
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/DataExtractor.h"
diff --git a/lib/DebugInfo/DWARFAcceleratorTable.cpp b/lib/DebugInfo/DWARFAcceleratorTable.cpp
new file mode 100644
index 0000000..703274d
--- /dev/null
+++ b/lib/DebugInfo/DWARFAcceleratorTable.cpp
@@ -0,0 +1,133 @@
+//===--- DWARFAcceleratorTable.cpp ----------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFAcceleratorTable.h"
+
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+
+bool DWARFAcceleratorTable::extract() {
+  uint32_t Offset = 0;
+
+  // Check that we can at least read the header.
+  if (!AccelSection.isValidOffset(offsetof(Header, HeaderDataLength)+4))
+    return false;
+
+  Hdr.Magic = AccelSection.getU32(&Offset);
+  Hdr.Version = AccelSection.getU16(&Offset);
+  Hdr.HashFunction = AccelSection.getU16(&Offset);
+  Hdr.NumBuckets = AccelSection.getU32(&Offset);
+  Hdr.NumHashes = AccelSection.getU32(&Offset);
+  Hdr.HeaderDataLength = AccelSection.getU32(&Offset);
+
+  // Check that we can read all the hashes and offsets from the
+  // section (see SourceLevelDebugging.rst for the structure of the index).
+  if (!AccelSection.isValidOffset(sizeof(Hdr) + Hdr.HeaderDataLength +
+                                  Hdr.NumBuckets*4 + Hdr.NumHashes*8))
+    return false;
+
+  HdrData.DIEOffsetBase = AccelSection.getU32(&Offset);
+  uint32_t NumAtoms = AccelSection.getU32(&Offset);
+
+  for (unsigned i = 0; i < NumAtoms; ++i) {
+    uint16_t AtomType = AccelSection.getU16(&Offset);
+    uint16_t AtomForm = AccelSection.getU16(&Offset);
+    HdrData.Atoms.push_back(std::make_pair(AtomType, AtomForm));
+  }
+
+  return true;
+}
+
+void DWARFAcceleratorTable::dump(raw_ostream &OS) const {
+  // Dump the header.
+  OS << "Magic = " << format("0x%08x", Hdr.Magic) << '\n'
+     << "Version = " << format("0x%04x", Hdr.Version) << '\n'
+     << "Hash function = " << format("0x%08x", Hdr.HashFunction) << '\n'
+     << "Bucket count = " << Hdr.NumBuckets << '\n'
+     << "Hashes count = " << Hdr.NumHashes << '\n'
+     << "HeaderData length = " << Hdr.HeaderDataLength << '\n'
+     << "DIE offset base = " << HdrData.DIEOffsetBase << '\n'
+     << "Number of atoms = " << HdrData.Atoms.size() << '\n';
+
+  unsigned i = 0;
+  SmallVector<DWARFFormValue, 3> AtomForms;
+  for (const auto &Atom: HdrData.Atoms) {
+    OS << format("Atom[%d] Type: ", i++);
+    if (const char *TypeString = dwarf::AtomTypeString(Atom.first))
+      OS << TypeString;
+    else
+      OS << format("DW_ATOM_Unknown_0x%x", Atom.first);
+    OS << " Form: ";
+    if (const char *FormString = dwarf::FormEncodingString(Atom.second))
+      OS << FormString;
+    else
+      OS << format("DW_FORM_Unknown_0x%x", Atom.second);
+    OS << '\n';
+    AtomForms.push_back(DWARFFormValue(Atom.second));
+  }
+
+  // Now go through the actual tables and dump them.
+  uint32_t Offset = sizeof(Hdr) + Hdr.HeaderDataLength;
+  unsigned HashesBase = Offset + Hdr.NumBuckets * 4;
+  unsigned OffsetsBase = HashesBase + Hdr.NumHashes * 4;
+
+  for (unsigned Bucket = 0; Bucket < Hdr.NumBuckets; ++Bucket) {
+    unsigned Index = AccelSection.getU32(&Offset);
+
+    OS << format("Bucket[%d]\n", Bucket);
+    if (Index == UINT32_MAX) {
+      OS << "  EMPTY\n";
+      continue;
+    }
+
+    for (unsigned HashIdx = Index; HashIdx < Hdr.NumHashes; ++HashIdx) {
+      unsigned HashOffset = HashesBase + HashIdx*4;
+      unsigned OffsetsOffset = OffsetsBase + HashIdx*4;
+      uint32_t Hash = AccelSection.getU32(&HashOffset);
+
+      if (Hash % Hdr.NumBuckets != Bucket)
+        break;
+
+      unsigned DataOffset = AccelSection.getU32(&OffsetsOffset);
+      OS << format("  Hash = 0x%08x Offset = 0x%08x\n", Hash, DataOffset);
+      if (!AccelSection.isValidOffset(DataOffset)) {
+        OS << "    Invalid section offset\n";
+        continue;
+      }
+      while (AccelSection.isValidOffsetForDataOfSize(DataOffset, 4)) {
+        unsigned StringOffset = AccelSection.getU32(&DataOffset);
+        RelocAddrMap::const_iterator Reloc = Relocs.find(DataOffset-4);
+        if (Reloc != Relocs.end())
+          StringOffset += Reloc->second.second;
+        if (!StringOffset)
+          break;
+        OS << format("    Name: %08x \"%s\"\n", StringOffset,
+                     StringSection.getCStr(&StringOffset));
+        unsigned NumData = AccelSection.getU32(&DataOffset);
+        for (unsigned Data = 0; Data < NumData; ++Data) {
+          OS << format("    Data[%d] => ", Data);
+          unsigned i = 0;
+          for (auto &Atom : AtomForms) {
+            OS << format("{Atom[%d]: ", i++);
+            if (Atom.extractValue(AccelSection, &DataOffset, nullptr))
+              Atom.dump(OS, nullptr);
+            else
+              OS << "Error extracting the value";
+            OS << "} ";
+          }
+          OS << '\n';
+        }
+      }
+    }
+  }
+}
+}
diff --git a/lib/DebugInfo/DWARFAcceleratorTable.h b/lib/DebugInfo/DWARFAcceleratorTable.h
new file mode 100644
index 0000000..7dc9591
--- /dev/null
+++ b/lib/DebugInfo/DWARFAcceleratorTable.h
@@ -0,0 +1,51 @@
+//===--- DWARFAcceleratorTable.h --------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFRelocMap.h"
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/DebugInfo/DWARFFormValue.h"
+
+#include <cstdint>
+
+namespace llvm {
+
+class DWARFAcceleratorTable {
+
+  struct Header {
+    uint32_t Magic;
+    uint16_t Version;
+    uint16_t HashFunction;
+    uint32_t NumBuckets;
+    uint32_t NumHashes;
+    uint32_t HeaderDataLength;
+  };
+
+  struct HeaderData {
+    typedef uint16_t AtomType;
+    typedef uint16_t Form;
+    uint32_t DIEOffsetBase;
+    SmallVector<std::pair<AtomType, Form>, 3> Atoms;
+  };
+
+  struct Header Hdr;
+  struct HeaderData HdrData;
+  DataExtractor AccelSection;
+  DataExtractor StringSection;
+  const RelocAddrMap& Relocs;
+public:
+  DWARFAcceleratorTable(DataExtractor AccelSection, DataExtractor StringSection,
+                        const RelocAddrMap &Relocs)
+    : AccelSection(AccelSection), StringSection(StringSection), Relocs(Relocs) {}
+
+  bool extract();
+  void dump(raw_ostream &OS) const;
+};
+
+}
diff --git a/lib/DebugInfo/DWARFCompileUnit.h b/lib/DebugInfo/DWARFCompileUnit.h
index 2ed188e..b3190b18 100644
--- a/lib/DebugInfo/DWARFCompileUnit.h
+++ b/lib/DebugInfo/DWARFCompileUnit.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFCOMPILEUNIT_H
-#define LLVM_DEBUGINFO_DWARFCOMPILEUNIT_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFCOMPILEUNIT_H
+#define LLVM_LIB_DEBUGINFO_DWARFCOMPILEUNIT_H
 
 #include "DWARFUnit.h"
 
@@ -16,10 +16,11 @@ namespace llvm {
 
 class DWARFCompileUnit : public DWARFUnit {
 public:
-  DWARFCompileUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef RS,
-                   StringRef SS, StringRef SOS, StringRef AOS,
-                   const RelocAddrMap *M, bool LE)
-      : DWARFUnit(DA, IS, RS, SS, SOS, AOS, M, LE) {}
+  DWARFCompileUnit(DWARFContext &Context, const DWARFSection &Section,
+                   const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                   StringRef SOS, StringRef AOS, bool LE,
+                   const DWARFUnitSectionBase &UnitSection)
+      : DWARFUnit(Context, Section, DA, RS, SS, SOS, AOS, LE, UnitSection) {}
   void dump(raw_ostream &OS);
   // VTable anchor.
   ~DWARFCompileUnit() override;
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index 3961905..9a2c7cc 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -9,6 +9,7 @@
 
 #include "DWARFContext.h"
 #include "DWARFDebugArangeSet.h"
+#include "DWARFAcceleratorTable.h"
 
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -59,6 +60,18 @@ static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data,
   }
 }
 
+static void dumpAccelSection(raw_ostream &OS, StringRef Name,
+                             const DWARFSection& Section, StringRef StringSection,
+                             bool LittleEndian) {
+  DataExtractor AccelSection(Section.Data, LittleEndian, 0);
+  DataExtractor StrData(StringSection, LittleEndian, 0);
+  OS << "\n." << Name << " contents:\n";
+  DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs);
+  if (!Accel.extract())
+    return;
+  Accel.dump(OS);
+}
+
 void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
   if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
     OS << ".debug_abbrev contents:\n";
@@ -86,15 +99,17 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
 
   if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
     OS << "\n.debug_types contents:\n";
-    for (const auto &TU : type_units())
-      TU->dump(OS);
+    for (const auto &TUS : type_unit_sections())
+      for (const auto &TU : TUS)
+        TU->dump(OS);
   }
 
   if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
       getNumDWOTypeUnits()) {
     OS << "\n.debug_types.dwo contents:\n";
-    for (const auto &DWOTU : dwo_type_units())
-      DWOTU->dump(OS);
+    for (const auto &DWOTUS : dwo_type_unit_sections())
+      for (const auto &DWOTU : DWOTUS)
+        DWOTU->dump(OS);
   }
 
   if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
@@ -216,6 +231,22 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
       OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
     }
   }
+
+  if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
+    dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
+                     getStringSection(), isLittleEndian());
+
+  if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
+    dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
+                     getStringSection(), isLittleEndian());
+
+  if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
+    dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
+                     getStringSection(), isLittleEndian());
+
+  if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
+    dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
+                     getStringSection(), isLittleEndian());
 }
 
 const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
@@ -291,7 +322,7 @@ const DWARFDebugFrame *DWARFContext::getDebugFrame() {
 }
 
 const DWARFLineTable *
-DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
+DWARFContext::getLineTableForUnit(DWARFUnit *cu) {
   if (!Line)
     Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
 
@@ -312,110 +343,34 @@ DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
 }
 
 void DWARFContext::parseCompileUnits() {
-  if (!CUs.empty())
-    return;
-  uint32_t offset = 0;
-  const DataExtractor &DIData = DataExtractor(getInfoSection().Data,
-                                              isLittleEndian(), 0);
-  while (DIData.isValidOffset(offset)) {
-    std::unique_ptr<DWARFCompileUnit> CU(new DWARFCompileUnit(
-        getDebugAbbrev(), getInfoSection().Data, getRangeSection(),
-        getStringSection(), StringRef(), getAddrSection(),
-        &getInfoSection().Relocs, isLittleEndian()));
-    if (!CU->extract(DIData, &offset)) {
-      break;
-    }
-    CUs.push_back(std::move(CU));
-    offset = CUs.back()->getNextUnitOffset();
-  }
+  CUs.parse(*this, getInfoSection());
 }
 
 void DWARFContext::parseTypeUnits() {
   if (!TUs.empty())
     return;
   for (const auto &I : getTypesSections()) {
-    uint32_t offset = 0;
-    const DataExtractor &DIData =
-        DataExtractor(I.second.Data, isLittleEndian(), 0);
-    while (DIData.isValidOffset(offset)) {
-      std::unique_ptr<DWARFTypeUnit> TU(
-          new DWARFTypeUnit(getDebugAbbrev(), I.second.Data, getRangeSection(),
-                            getStringSection(), StringRef(), getAddrSection(),
-                            &I.second.Relocs, isLittleEndian()));
-      if (!TU->extract(DIData, &offset))
-        break;
-      TUs.push_back(std::move(TU));
-      offset = TUs.back()->getNextUnitOffset();
-    }
+    TUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
+    TUs.back().parse(*this, I.second);
   }
 }
 
 void DWARFContext::parseDWOCompileUnits() {
-  if (!DWOCUs.empty())
-    return;
-  uint32_t offset = 0;
-  const DataExtractor &DIData =
-      DataExtractor(getInfoDWOSection().Data, isLittleEndian(), 0);
-  while (DIData.isValidOffset(offset)) {
-    std::unique_ptr<DWARFCompileUnit> DWOCU(new DWARFCompileUnit(
-        getDebugAbbrevDWO(), getInfoDWOSection().Data, getRangeDWOSection(),
-        getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
-        &getInfoDWOSection().Relocs, isLittleEndian()));
-    if (!DWOCU->extract(DIData, &offset)) {
-      break;
-    }
-    DWOCUs.push_back(std::move(DWOCU));
-    offset = DWOCUs.back()->getNextUnitOffset();
-  }
+  DWOCUs.parseDWO(*this, getInfoDWOSection());
 }
 
 void DWARFContext::parseDWOTypeUnits() {
   if (!DWOTUs.empty())
     return;
   for (const auto &I : getTypesDWOSections()) {
-    uint32_t offset = 0;
-    const DataExtractor &DIData =
-        DataExtractor(I.second.Data, isLittleEndian(), 0);
-    while (DIData.isValidOffset(offset)) {
-      std::unique_ptr<DWARFTypeUnit> TU(new DWARFTypeUnit(
-          getDebugAbbrevDWO(), I.second.Data, getRangeDWOSection(),
-          getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
-          &I.second.Relocs, isLittleEndian()));
-      if (!TU->extract(DIData, &offset))
-        break;
-      DWOTUs.push_back(std::move(TU));
-      offset = DWOTUs.back()->getNextUnitOffset();
-    }
+    DWOTUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
+    DWOTUs.back().parseDWO(*this, I.second);
   }
 }
 
-namespace {
-  struct OffsetComparator {
-
-    bool operator()(const std::unique_ptr<DWARFCompileUnit> &LHS,
-                    const std::unique_ptr<DWARFCompileUnit> &RHS) const {
-      return LHS->getOffset() < RHS->getOffset();
-    }
-    bool operator()(const std::unique_ptr<DWARFCompileUnit> &LHS,
-                    uint32_t RHS) const {
-      return LHS->getOffset() < RHS;
-    }
-    bool operator()(uint32_t LHS,
-                    const std::unique_ptr<DWARFCompileUnit> &RHS) const {
-      return LHS < RHS->getOffset();
-    }
-  };
-}
-
 DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
   parseCompileUnits();
-
-  std::unique_ptr<DWARFCompileUnit> *CU =
-      std::lower_bound(CUs.begin(), CUs.end(), Offset, OffsetComparator());
-  if (CU != CUs.end()) {
-    return CU->get();
-  }
-  return nullptr;
+  return CUs.getUnitForOffset(Offset);
 }
 
 DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
@@ -425,47 +380,6 @@ DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
   return getCompileUnitForOffset(CUOffset);
 }
 
-static bool getFileNameForCompileUnit(DWARFCompileUnit *CU,
-                                      const DWARFLineTable *LineTable,
-                                      uint64_t FileIndex, FileLineInfoKind Kind,
-                                      std::string &FileName) {
-  if (!CU || !LineTable || Kind == FileLineInfoKind::None ||
-      !LineTable->getFileNameByIndex(FileIndex, Kind, FileName))
-    return false;
-  if (Kind == FileLineInfoKind::AbsoluteFilePath &&
-      sys::path::is_relative(FileName)) {
-    // We may still need to append compilation directory of compile unit.
-    SmallString<16> AbsolutePath;
-    if (const char *CompilationDir = CU->getCompilationDir()) {
-      sys::path::append(AbsolutePath, CompilationDir);
-    }
-    sys::path::append(AbsolutePath, FileName);
-    FileName = AbsolutePath.str();
-  }
-  return true;
-}
-
-static bool getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
-                                          const DWARFLineTable *LineTable,
-                                          uint64_t Address,
-                                          FileLineInfoKind Kind,
-                                          DILineInfo &Result) {
-  if (!CU || !LineTable)
-    return false;
-  // Get the index of row we're looking for in the line table.
-  uint32_t RowIndex = LineTable->lookupAddress(Address);
-  if (RowIndex == -1U)
-    return false;
-  // Take file number and line/column from the row.
-  const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
-  if (!getFileNameForCompileUnit(CU, LineTable, Row.File, Kind,
-                                 Result.FileName))
-    return false;
-  Result.Line = Row.Line;
-  Result.Column = Row.Column;
-  return true;
-}
-
 static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
                                       FunctionNameKind Kind,
                                       std::string &FunctionName) {
@@ -496,8 +410,9 @@ DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
     return Result;
   getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
   if (Spec.FLIKind != FileLineInfoKind::None) {
-    const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
-    getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind, Result);
+    if (const DWARFLineTable *LineTable = getLineTableForUnit(CU))
+      LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
+                                           Spec.FLIKind, Result);
   }
   return Result;
 }
@@ -522,7 +437,7 @@ DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
     return Lines;
   }
 
-  const DWARFLineTable *LineTable = getLineTableForCompileUnit(CU);
+  const DWARFLineTable *LineTable = getLineTableForUnit(CU);
 
   // Get the index of row we're looking for in the line table.
   std::vector<uint32_t> RowVector;
@@ -533,8 +448,8 @@ DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
     // Take file number and line/column from the row.
     const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
     DILineInfo Result;
-    getFileNameForCompileUnit(CU, LineTable, Row.File, Spec.FLIKind,
-                              Result.FileName);
+    LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
+                                  Spec.FLIKind, Result.FileName);
     Result.FunctionName = FunctionName;
     Result.Line = Row.Line;
     Result.Column = Row.Column;
@@ -561,11 +476,11 @@ DWARFContext::getInliningInfoForAddress(uint64_t Address,
     // try to at least get file/line info from symbol table.
     if (Spec.FLIKind != FileLineInfoKind::None) {
       DILineInfo Frame;
-      LineTable = getLineTableForCompileUnit(CU);
-      if (getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind,
-                                        Frame)) {
+      LineTable = getLineTableForUnit(CU);
+      if (LineTable &&
+          LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
+                                               Spec.FLIKind, Frame))
         InliningInfo.addFrame(Frame);
-      }
     }
     return InliningInfo;
   }
@@ -582,15 +497,17 @@ DWARFContext::getInliningInfoForAddress(uint64_t Address,
       if (i == 0) {
         // For the topmost frame, initialize the line table of this
         // compile unit and fetch file/line info from it.
-        LineTable = getLineTableForCompileUnit(CU);
+        LineTable = getLineTableForUnit(CU);
         // For the topmost routine, get file/line info from line table.
-        getFileLineInfoForCompileUnit(CU, LineTable, Address, Spec.FLIKind,
-                                      Frame);
+        if (LineTable)
+          LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
+                                               Spec.FLIKind, Frame);
       } else {
         // Otherwise, use call file, call line and call column from
         // previous DIE in inlined chain.
-        getFileNameForCompileUnit(CU, LineTable, CallFile, Spec.FLIKind,
-                                  Frame.FileName);
+        if (LineTable)
+          LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
+                                        Spec.FLIKind, Frame.FileName);
         Frame.Line = CallLine;
         Frame.Column = CallColumn;
       }
@@ -621,12 +538,19 @@ static bool consumeCompressedDebugSectionHeader(StringRef &data,
   return true;
 }
 
-DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
-    : IsLittleEndian(Obj->isLittleEndian()),
-      AddressSize(Obj->getBytesInAddress()) {
-  for (const SectionRef &Section : Obj->sections()) {
+DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj)
+    : IsLittleEndian(Obj.isLittleEndian()),
+      AddressSize(Obj.getBytesInAddress()) {
+  for (const SectionRef &Section : Obj.sections()) {
     StringRef name;
     Section.getName(name);
+    // Skip BSS and Virtual sections, they aren't interesting.
+    bool IsBSS = Section.isBSS();
+    if (IsBSS)
+      continue;
+    bool IsVirtual = Section.isVirtual();
+    if (IsVirtual)
+      continue;
     StringRef data;
     Section.getContents(data);
 
@@ -670,6 +594,11 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
             .Case("debug_str.dwo", &StringDWOSection)
             .Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
             .Case("debug_addr", &AddrSection)
+            .Case("apple_names", &AppleNamesSection.Data)
+            .Case("apple_types", &AppleTypesSection.Data)
+            .Case("apple_namespaces", &AppleNamespacesSection.Data)
+            .Case("apple_namespac", &AppleNamespacesSection.Data)
+            .Case("apple_objc", &AppleObjCSection.Data)
             // Any more debug info sections go here.
             .Default(nullptr);
     if (SectionData) {
@@ -687,7 +616,7 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
     }
 
     section_iterator RelocatedSection = Section.getRelocatedSection();
-    if (RelocatedSection == Obj->section_end())
+    if (RelocatedSection == Obj.section_end())
       continue;
 
     StringRef RelSecName;
@@ -702,6 +631,11 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
         .Case("debug_loc", &LocSection.Relocs)
         .Case("debug_info.dwo", &InfoDWOSection.Relocs)
         .Case("debug_line", &LineSection.Relocs)
+        .Case("apple_names", &AppleNamesSection.Relocs)
+        .Case("apple_types", &AppleTypesSection.Relocs)
+        .Case("apple_namespaces", &AppleNamespacesSection.Relocs)
+        .Case("apple_namespac", &AppleNamespacesSection.Relocs)
+        .Case("apple_objc", &AppleObjCSection.Relocs)
         .Default(nullptr);
     if (!Map) {
       // Find debug_types relocs by section rather than name as there are
@@ -715,23 +649,19 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj)
     }
 
     if (Section.relocation_begin() != Section.relocation_end()) {
-      uint64_t SectionSize;
-      RelocatedSection->getSize(SectionSize);
+      uint64_t SectionSize = RelocatedSection->getSize();
       for (const RelocationRef &Reloc : Section.relocations()) {
         uint64_t Address;
         Reloc.getOffset(Address);
         uint64_t Type;
         Reloc.getType(Type);
         uint64_t SymAddr = 0;
-        // ELF relocations may need the symbol address
-        if (Obj->isELF()) {
-          object::symbol_iterator Sym = Reloc.getSymbol();
+        object::symbol_iterator Sym = Reloc.getSymbol();
+        if (Sym != Obj.symbol_end())
           Sym->getAddress(SymAddr);
-        }
 
-        object::RelocVisitor V(Obj->getFileFormatName());
-        // The section address is always 0 for debug sections.
-        object::RelocToApply R(V.visit(Type, Reloc, 0, SymAddr));
+        object::RelocVisitor V(Obj);
+        object::RelocToApply R(V.visit(Type, Reloc, SymAddr));
         if (V.error()) {
           SmallString<32> Name;
           std::error_code ec(Reloc.getTypeName(Name));
diff --git a/lib/DebugInfo/DWARFContext.h b/lib/DebugInfo/DWARFContext.h
index 6d1ae92..dd3fcc7 100644
--- a/lib/DebugInfo/DWARFContext.h
+++ b/lib/DebugInfo/DWARFContext.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===/
 
-#ifndef LLVM_DEBUGINFO_DWARFCONTEXT_H
-#define LLVM_DEBUGINFO_DWARFCONTEXT_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFCONTEXT_H
+#define LLVM_LIB_DEBUGINFO_DWARFCONTEXT_H
 
 #include "DWARFCompileUnit.h"
 #include "DWARFDebugAranges.h"
@@ -16,10 +16,12 @@
 #include "DWARFDebugLine.h"
 #include "DWARFDebugLoc.h"
 #include "DWARFDebugRangeList.h"
+#include "DWARFSection.h"
 #include "DWARFTypeUnit.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/DebugInfo/DIContext.h"
+#include <vector>
 
 namespace llvm {
 
@@ -28,19 +30,17 @@ namespace llvm {
 /// information parsing. The actual data is supplied through pure virtual
 /// methods that a concrete implementation provides.
 class DWARFContext : public DIContext {
-  typedef SmallVector<std::unique_ptr<DWARFCompileUnit>, 1> CUVector;
-  typedef SmallVector<std::unique_ptr<DWARFTypeUnit>, 1> TUVector;
 
-  CUVector CUs;
-  TUVector TUs;
+  DWARFUnitSection<DWARFCompileUnit> CUs;
+  std::vector<DWARFUnitSection<DWARFTypeUnit>> TUs;
   std::unique_ptr<DWARFDebugAbbrev> Abbrev;
   std::unique_ptr<DWARFDebugLoc> Loc;
   std::unique_ptr<DWARFDebugAranges> Aranges;
   std::unique_ptr<DWARFDebugLine> Line;
   std::unique_ptr<DWARFDebugFrame> DebugFrame;
 
-  CUVector DWOCUs;
-  TUVector DWOTUs;
+  DWARFUnitSection<DWARFCompileUnit> DWOCUs;
+  std::vector<DWARFUnitSection<DWARFTypeUnit>> DWOTUs;
   std::unique_ptr<DWARFDebugAbbrev> AbbrevDWO;
   std::unique_ptr<DWARFDebugLocDWO> LocDWO;
 
@@ -64,11 +64,6 @@ class DWARFContext : public DIContext {
   void parseDWOTypeUnits();
 
 public:
-  struct Section {
-    StringRef Data;
-    RelocAddrMap Relocs;
-  };
-
   DWARFContext() : DIContext(CK_DWARF) {}
 
   static bool classof(const DIContext *DICtx) {
@@ -77,8 +72,9 @@ public:
 
   void dump(raw_ostream &OS, DIDumpType DumpType = DIDT_All) override;
 
-  typedef iterator_range<CUVector::iterator> cu_iterator_range;
-  typedef iterator_range<TUVector::iterator> tu_iterator_range;
+  typedef DWARFUnitSection<DWARFCompileUnit>::iterator_range cu_iterator_range;
+  typedef DWARFUnitSection<DWARFTypeUnit>::iterator_range tu_iterator_range;
+  typedef iterator_range<std::vector<DWARFUnitSection<DWARFTypeUnit>>::iterator> tu_section_iterator_range;
 
   /// Get compile units in this context.
   cu_iterator_range compile_units() {
@@ -87,9 +83,9 @@ public:
   }
 
   /// Get type units in this context.
-  tu_iterator_range type_units() {
+  tu_section_iterator_range type_unit_sections() {
     parseTypeUnits();
-    return tu_iterator_range(TUs.begin(), TUs.end());
+    return tu_section_iterator_range(TUs.begin(), TUs.end());
   }
 
   /// Get compile units in the DWO context.
@@ -99,9 +95,9 @@ public:
   }
 
   /// Get type units in the DWO context.
-  tu_iterator_range dwo_type_units() {
+  tu_section_iterator_range dwo_type_unit_sections() {
     parseDWOTypeUnits();
-    return tu_iterator_range(DWOTUs.begin(), DWOTUs.end());
+    return tu_section_iterator_range(DWOTUs.begin(), DWOTUs.end());
   }
 
   /// Get the number of compile units in this context.
@@ -159,8 +155,7 @@ public:
   const DWARFDebugFrame *getDebugFrame();
 
   /// Get a pointer to a parsed line table corresponding to a compile unit.
-  const DWARFDebugLine::LineTable *
-  getLineTableForCompileUnit(DWARFCompileUnit *cu);
+  const DWARFDebugLine::LineTable *getLineTableForUnit(DWARFUnit *cu);
 
   DILineInfo getLineInfoForAddress(uint64_t Address,
       DILineInfoSpecifier Specifier = DILineInfoSpecifier()) override;
@@ -171,17 +166,15 @@ public:
 
   virtual bool isLittleEndian() const = 0;
   virtual uint8_t getAddressSize() const = 0;
-  virtual const Section &getInfoSection() = 0;
-  typedef MapVector<object::SectionRef, Section,
-                    std::map<object::SectionRef, unsigned> > TypeSectionMap;
+  virtual const DWARFSection &getInfoSection() = 0;
+  typedef MapVector<object::SectionRef, DWARFSection,
+                    std::map<object::SectionRef, unsigned>> TypeSectionMap;
   virtual const TypeSectionMap &getTypesSections() = 0;
   virtual StringRef getAbbrevSection() = 0;
-  virtual const Section &getLocSection() = 0;
-  virtual const Section &getLocDWOSection() = 0;
+  virtual const DWARFSection &getLocSection() = 0;
   virtual StringRef getARangeSection() = 0;
   virtual StringRef getDebugFrameSection() = 0;
-  virtual const Section &getLineSection() = 0;
-  virtual const Section &getLineDWOSection() = 0;
+  virtual const DWARFSection &getLineSection() = 0;
   virtual StringRef getStringSection() = 0;
   virtual StringRef getRangeSection() = 0;
   virtual StringRef getPubNamesSection() = 0;
@@ -190,13 +183,19 @@ public:
   virtual StringRef getGnuPubTypesSection() = 0;
 
   // Sections for DWARF5 split dwarf proposal.
-  virtual const Section &getInfoDWOSection() = 0;
+  virtual const DWARFSection &getInfoDWOSection() = 0;
   virtual const TypeSectionMap &getTypesDWOSections() = 0;
   virtual StringRef getAbbrevDWOSection() = 0;
+  virtual const DWARFSection &getLineDWOSection() = 0;
+  virtual const DWARFSection &getLocDWOSection() = 0;
   virtual StringRef getStringDWOSection() = 0;
   virtual StringRef getStringOffsetDWOSection() = 0;
   virtual StringRef getRangeDWOSection() = 0;
   virtual StringRef getAddrSection() = 0;
+  virtual const DWARFSection& getAppleNamesSection() = 0;
+  virtual const DWARFSection& getAppleTypesSection() = 0;
+  virtual const DWARFSection& getAppleNamespacesSection() = 0;
+  virtual const DWARFSection& getAppleObjCSection() = 0;
 
   static bool isSupportedVersion(unsigned version) {
     return version == 2 || version == 3 || version == 4;
@@ -217,15 +216,13 @@ class DWARFContextInMemory : public DWARFContext {
   virtual void anchor();
   bool IsLittleEndian;
   uint8_t AddressSize;
-  Section InfoSection;
+  DWARFSection InfoSection;
   TypeSectionMap TypesSections;
   StringRef AbbrevSection;
-  Section LocSection;
-  Section LocDWOSection;
+  DWARFSection LocSection;
   StringRef ARangeSection;
   StringRef DebugFrameSection;
-  Section LineSection;
-  Section LineDWOSection;
+  DWARFSection LineSection;
   StringRef StringSection;
   StringRef RangeSection;
   StringRef PubNamesSection;
@@ -234,42 +231,52 @@ class DWARFContextInMemory : public DWARFContext {
   StringRef GnuPubTypesSection;
 
   // Sections for DWARF5 split dwarf proposal.
-  Section InfoDWOSection;
+  DWARFSection InfoDWOSection;
   TypeSectionMap TypesDWOSections;
   StringRef AbbrevDWOSection;
+  DWARFSection LineDWOSection;
+  DWARFSection LocDWOSection;
   StringRef StringDWOSection;
   StringRef StringOffsetDWOSection;
   StringRef RangeDWOSection;
   StringRef AddrSection;
+  DWARFSection AppleNamesSection;
+  DWARFSection AppleTypesSection;
+  DWARFSection AppleNamespacesSection;
+  DWARFSection AppleObjCSection;
 
   SmallVector<SmallString<32>, 4> UncompressedSections;
 
 public:
-  DWARFContextInMemory(object::ObjectFile *);
+  DWARFContextInMemory(const object::ObjectFile &Obj);
   bool isLittleEndian() const override { return IsLittleEndian; }
   uint8_t getAddressSize() const override { return AddressSize; }
-  const Section &getInfoSection() override { return InfoSection; }
+  const DWARFSection &getInfoSection() override { return InfoSection; }
   const TypeSectionMap &getTypesSections() override { return TypesSections; }
   StringRef getAbbrevSection() override { return AbbrevSection; }
-  const Section &getLocSection() override { return LocSection; }
-  const Section &getLocDWOSection() override { return LocDWOSection; }
+  const DWARFSection &getLocSection() override { return LocSection; }
   StringRef getARangeSection() override { return ARangeSection; }
   StringRef getDebugFrameSection() override { return DebugFrameSection; }
-  const Section &getLineSection() override { return LineSection; }
-  const Section &getLineDWOSection() override { return LineDWOSection; }
+  const DWARFSection &getLineSection() override { return LineSection; }
   StringRef getStringSection() override { return StringSection; }
   StringRef getRangeSection() override { return RangeSection; }
   StringRef getPubNamesSection() override { return PubNamesSection; }
   StringRef getPubTypesSection() override { return PubTypesSection; }
   StringRef getGnuPubNamesSection() override { return GnuPubNamesSection; }
   StringRef getGnuPubTypesSection() override { return GnuPubTypesSection; }
+  const DWARFSection& getAppleNamesSection() override { return AppleNamesSection; }
+  const DWARFSection& getAppleTypesSection() override { return AppleTypesSection; }
+  const DWARFSection& getAppleNamespacesSection() override { return AppleNamespacesSection; }
+  const DWARFSection& getAppleObjCSection() override { return AppleObjCSection; }
 
   // Sections for DWARF5 split dwarf proposal.
-  const Section &getInfoDWOSection() override { return InfoDWOSection; }
+  const DWARFSection &getInfoDWOSection() override { return InfoDWOSection; }
   const TypeSectionMap &getTypesDWOSections() override {
     return TypesDWOSections;
   }
   StringRef getAbbrevDWOSection() override { return AbbrevDWOSection; }
+  const DWARFSection &getLineDWOSection() override { return LineDWOSection; }
+  const DWARFSection &getLocDWOSection() override { return LocDWOSection; }
   StringRef getStringDWOSection() override { return StringDWOSection; }
   StringRef getStringOffsetDWOSection() override {
     return StringOffsetDWOSection;
diff --git a/lib/DebugInfo/DWARFDebugAbbrev.cpp b/lib/DebugInfo/DWARFDebugAbbrev.cpp
index 8426bf9..c1a088e 100644
--- a/lib/DebugInfo/DWARFDebugAbbrev.cpp
+++ b/lib/DebugInfo/DWARFDebugAbbrev.cpp
@@ -30,7 +30,6 @@ bool DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
   DWARFAbbreviationDeclaration AbbrDecl;
   uint32_t PrevAbbrCode = 0;
   while (AbbrDecl.extract(Data, OffsetPtr)) {
-    Decls.push_back(AbbrDecl);
     if (FirstAbbrCode == 0) {
       FirstAbbrCode = AbbrDecl.getCode();
     } else {
@@ -40,6 +39,7 @@ bool DWARFAbbreviationDeclarationSet::extract(DataExtractor Data,
       }
     }
     PrevAbbrCode = AbbrDecl.getCode();
+    Decls.push_back(std::move(AbbrDecl));
   }
   return BeginOffset != *OffsetPtr;
 }
@@ -82,7 +82,7 @@ void DWARFDebugAbbrev::extract(DataExtractor Data) {
     uint32_t CUAbbrOffset = Offset;
     if (!AbbrDecls.extract(Data, &Offset))
       break;
-    AbbrDeclSets[CUAbbrOffset] = AbbrDecls;
+    AbbrDeclSets[CUAbbrOffset] = std::move(AbbrDecls);
   }
 }
 
diff --git a/lib/DebugInfo/DWARFDebugAbbrev.h b/lib/DebugInfo/DWARFDebugAbbrev.h
index 3a9adba..4b3b814 100644
--- a/lib/DebugInfo/DWARFDebugAbbrev.h
+++ b/lib/DebugInfo/DWARFDebugAbbrev.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGABBREV_H
-#define LLVM_DEBUGINFO_DWARFDEBUGABBREV_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGABBREV_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGABBREV_H
 
 #include "DWARFAbbreviationDeclaration.h"
 #include <list>
diff --git a/lib/DebugInfo/DWARFDebugArangeSet.h b/lib/DebugInfo/DWARFDebugArangeSet.h
index d6c2d8b..837a8e6 100644
--- a/lib/DebugInfo/DWARFDebugArangeSet.h
+++ b/lib/DebugInfo/DWARFDebugArangeSet.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGARANGESET_H
-#define LLVM_DEBUGINFO_DWARFDEBUGARANGESET_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGARANGESET_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGARANGESET_H
 
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/DataExtractor.h"
diff --git a/lib/DebugInfo/DWARFDebugAranges.h b/lib/DebugInfo/DWARFDebugAranges.h
index a9f37fe..791f010 100644
--- a/lib/DebugInfo/DWARFDebugAranges.h
+++ b/lib/DebugInfo/DWARFDebugAranges.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGARANGES_H
-#define LLVM_DEBUGINFO_DWARFDEBUGARANGES_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGARANGES_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGARANGES_H
 
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/DataExtractor.h"
diff --git a/lib/DebugInfo/DWARFDebugFrame.cpp b/lib/DebugInfo/DWARFDebugFrame.cpp
index a33548e..dfa7e82 100644
--- a/lib/DebugInfo/DWARFDebugFrame.cpp
+++ b/lib/DebugInfo/DWARFDebugFrame.cpp
@@ -202,7 +202,8 @@ public:
       SmallString<8> Augmentation, uint64_t CodeAlignmentFactor,
       int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister)
       : FrameEntry(FK_CIE, Offset, Length), Version(Version),
-        Augmentation(Augmentation), CodeAlignmentFactor(CodeAlignmentFactor),
+        Augmentation(std::move(Augmentation)),
+        CodeAlignmentFactor(CodeAlignmentFactor),
         DataAlignmentFactor(DataAlignmentFactor),
         ReturnAddressRegister(ReturnAddressRegister) {}
 
diff --git a/lib/DebugInfo/DWARFDebugFrame.h b/lib/DebugInfo/DWARFDebugFrame.h
index bd4ef45..be925cb 100644
--- a/lib/DebugInfo/DWARFDebugFrame.h
+++ b/lib/DebugInfo/DWARFDebugFrame.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGFRAME_H
-#define LLVM_DEBUGINFO_DWARFDEBUGFRAME_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGFRAME_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGFRAME_H
 
 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Support/raw_ostream.h"
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index 2e7a54a..583e700 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -12,15 +12,26 @@
 #include "DWARFContext.h"
 #include "DWARFDebugAbbrev.h"
 #include "llvm/DebugInfo/DWARFFormValue.h"
+#include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 using namespace dwarf;
-typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
 
-void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, const DWARFUnit *u,
+// Small helper to extract a DIE pointed by a reference
+// attribute. It looks up the Unit containing the DIE and calls
+// DIE.extractFast with the right unit. Returns new unit on success,
+// nullptr otherwise.
+static const DWARFUnit *findUnitAndExtractFast(DWARFDebugInfoEntryMinimal &DIE,
+                                               const DWARFUnit *Unit,
+                                               uint32_t *Offset) {
+  Unit = Unit->getUnitSection().getUnitForOffset(*Offset);
+  return (Unit && DIE.extractFast(Unit, Offset)) ? Unit : nullptr;
+}
+
+void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, DWARFUnit *u,
                                       unsigned recurseDepth,
                                       unsigned indent) const {
   DataExtractor debug_info_data = u->getDebugInfoExtractor();
@@ -62,12 +73,42 @@ void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS, const DWARFUnit *u,
   }
 }
 
+static void dumpApplePropertyAttribute(raw_ostream &OS, uint64_t Val) {
+  OS << " (";
+  do {
+    uint64_t Bit = 1ULL << countTrailingZeros(Val);
+    if (const char *PropName = ApplePropertyString(Bit))
+      OS << PropName;
+    else
+      OS << format("DW_APPLE_PROPERTY_0x%" PRIx64, Bit);
+    if (!(Val ^= Bit))
+      break;
+    OS << ", ";
+  } while (true);
+  OS << ")";
+}
+
+static void dumpRanges(raw_ostream &OS, const DWARFAddressRangesVector& Ranges,
+                       unsigned AddressSize, unsigned Indent) {
+  if (Ranges.empty())
+    return;
+
+  for (const auto &Range: Ranges) {
+    OS << '\n';
+    OS.indent(Indent);
+    OS << format("[0x%0*" PRIx64 " - 0x%0*" PRIx64 ")",
+                 AddressSize*2, Range.first,
+                 AddressSize*2, Range.second);
+  }
+}
+
 void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
-                                               const DWARFUnit *u,
+                                               DWARFUnit *u,
                                                uint32_t *offset_ptr,
                                                uint16_t attr, uint16_t form,
                                                unsigned indent) const {
-  OS << "            ";
+  const char BaseIndent[] = "            ";
+  OS << BaseIndent;
   OS.indent(indent+2);
   const char *attrString = AttributeString(attr);
   if (attrString)
@@ -86,7 +127,48 @@ void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
     return;
 
   OS << "\t(";
-  formValue.dump(OS, u);
+  
+  const char *Name = nullptr;
+  std::string File;
+  if (attr == DW_AT_decl_file || attr == DW_AT_call_file) {
+    if (const auto *LT = u->getContext().getLineTableForUnit(u))
+      if (LT->getFileNameByIndex(
+             formValue.getAsUnsignedConstant().getValue(),
+             u->getCompilationDir(),
+             DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
+        File = '"' + File + '"';
+        Name = File.c_str();
+      }
+  } else if (Optional<uint64_t> Val = formValue.getAsUnsignedConstant())
+    Name = AttributeValueString(attr, *Val);
+
+  if (Name) {
+    OS << Name;
+  } else if (attr == DW_AT_decl_line || attr == DW_AT_call_line) {
+    OS << *formValue.getAsUnsignedConstant();
+  } else {
+    formValue.dump(OS, u);
+  }
+
+  // We have dumped the attribute raw value. For some attributes
+  // having both the raw value and the pretty-printed value is
+  // interesting. These attributes are handled below.
+  if ((attr == DW_AT_specification || attr == DW_AT_abstract_origin) &&
+      // The signature references aren't handled.
+      formValue.getForm() != DW_FORM_ref_sig8) {
+    uint32_t Ref = formValue.getAsReference(u).getValue();
+    DWARFDebugInfoEntryMinimal DIE;
+    if (const DWARFUnit *RefU = findUnitAndExtractFast(DIE, u, &Ref))
+      if (const char *Ref = DIE.getName(RefU, DINameKind::LinkageName))
+        OS << " \"" << Ref << '\"';
+  } else if (attr == DW_AT_APPLE_property_attribute) {
+    if (Optional<uint64_t> OptVal = formValue.getAsUnsignedConstant())
+      dumpApplePropertyAttribute(OS, *OptVal);
+  } else if (attr == DW_AT_ranges) {
+    dumpRanges(OS, getAddressRanges(u), u->getAddressByteSize(),
+               sizeof(BaseIndent)+indent+4);
+  }
+
   OS << ")\n";
 }
 
@@ -284,11 +366,19 @@ bool DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
 
 const char *
 DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
-                                              FunctionNameKind Kind) const {
-  if (!isSubroutineDIE() || Kind == FunctionNameKind::None)
+                                              DINameKind Kind) const {
+  if (!isSubroutineDIE())
+    return nullptr;
+  return getName(U, Kind);
+}
+
+const char *
+DWARFDebugInfoEntryMinimal::getName(const DWARFUnit *U,
+                                    DINameKind Kind) const {
+  if (Kind == DINameKind::None)
     return nullptr;
   // Try to get mangled name only if it was asked for.
-  if (Kind == FunctionNameKind::LinkageName) {
+  if (Kind == DINameKind::LinkageName) {
     if (const char *name =
             getAttributeValueAsString(U, DW_AT_MIPS_linkage_name, nullptr))
       return name;
@@ -303,8 +393,8 @@ DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
       getAttributeValueAsReference(U, DW_AT_specification, -1U);
   if (spec_ref != -1U) {
     DWARFDebugInfoEntryMinimal spec_die;
-    if (spec_die.extractFast(U, &spec_ref)) {
-      if (const char *name = spec_die.getSubroutineName(U, Kind))
+    if (const DWARFUnit *RefU = findUnitAndExtractFast(spec_die, U, &spec_ref)) {
+      if (const char *name = spec_die.getName(RefU, Kind))
         return name;
     }
   }
@@ -313,8 +403,9 @@ DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFUnit *U,
       getAttributeValueAsReference(U, DW_AT_abstract_origin, -1U);
   if (abs_origin_ref != -1U) {
     DWARFDebugInfoEntryMinimal abs_origin_die;
-    if (abs_origin_die.extractFast(U, &abs_origin_ref)) {
-      if (const char *name = abs_origin_die.getSubroutineName(U, Kind))
+    if (const DWARFUnit *RefU = findUnitAndExtractFast(abs_origin_die, U,
+                                                       &abs_origin_ref)) {
+      if (const char *name = abs_origin_die.getName(RefU, Kind))
         return name;
     }
   }
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.h b/lib/DebugInfo/DWARFDebugInfoEntry.h
index cc58eb6..7e7efb9 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.h
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGINFOENTRY_H
-#define LLVM_DEBUGINFO_DWARFDEBUGINFOENTRY_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGINFOENTRY_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGINFOENTRY_H
 
 #include "DWARFAbbreviationDeclaration.h"
 #include "DWARFDebugRangeList.h"
@@ -38,9 +38,9 @@ public:
   DWARFDebugInfoEntryMinimal()
     : Offset(0), SiblingIdx(0), AbbrevDecl(nullptr) {}
 
-  void dump(raw_ostream &OS, const DWARFUnit *u, unsigned recurseDepth,
+  void dump(raw_ostream &OS, DWARFUnit *u, unsigned recurseDepth,
             unsigned indent = 0) const;
-  void dumpAttribute(raw_ostream &OS, const DWARFUnit *u, uint32_t *offset_ptr,
+  void dumpAttribute(raw_ostream &OS, DWARFUnit *u, uint32_t *offset_ptr,
                      uint16_t attr, uint16_t form, unsigned indent = 0) const;
 
   /// Extracts a debug info entry, which is a child of a given unit,
@@ -125,9 +125,12 @@ public:
   /// returns its mangled name (or short name, if mangled is missing).
   /// This name may be fetched from specification or abstract origin
   /// for this subprogram. Returns null if no name is found.
-  const char *
-  getSubroutineName(const DWARFUnit *U,
-                    DILineInfoSpecifier::FunctionNameKind Kind) const;
+  const char *getSubroutineName(const DWARFUnit *U, DINameKind Kind) const;
+
+  /// Return the DIE name resolving DW_AT_sepcification or
+  /// DW_AT_abstract_origin references if necessary.
+  /// Returns null if no name is found.
+  const char *getName(const DWARFUnit *U, DINameKind Kind) const;
 
   /// Retrieves values of DW_AT_call_file, DW_AT_call_line and
   /// DW_AT_call_column from DIE (or zeroes if they are missing).
diff --git a/lib/DebugInfo/DWARFDebugLine.cpp b/lib/DebugInfo/DWARFDebugLine.cpp
index ce87635..a6ee461 100644
--- a/lib/DebugInfo/DWARFDebugLine.cpp
+++ b/lib/DebugInfo/DWARFDebugLine.cpp
@@ -644,6 +644,7 @@ bool DWARFDebugLine::LineTable::lookupAddressRange(
 
 bool
 DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
+                                              const char *CompDir,
                                               FileLineInfoKind Kind,
                                               std::string &Result) const {
   if (FileIndex == 0 || FileIndex > Prologue.FileNames.size() ||
@@ -656,15 +657,42 @@ DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
     Result = FileName;
     return true;
   }
+
   SmallString<16> FilePath;
   uint64_t IncludeDirIndex = Entry.DirIdx;
+  const char *IncludeDir = "";
   // Be defensive about the contents of Entry.
   if (IncludeDirIndex > 0 &&
-      IncludeDirIndex <= Prologue.IncludeDirectories.size()) {
-    const char *IncludeDir = Prologue.IncludeDirectories[IncludeDirIndex - 1];
-    sys::path::append(FilePath, IncludeDir);
-  }
-  sys::path::append(FilePath, FileName);
+      IncludeDirIndex <= Prologue.IncludeDirectories.size())
+    IncludeDir = Prologue.IncludeDirectories[IncludeDirIndex - 1];
+
+  // We may still need to append compilation directory of compile unit.
+  // We know that FileName is not absolute, the only way to have an
+  // absolute path at this point would be if IncludeDir is absolute.
+  if (CompDir && Kind == FileLineInfoKind::AbsoluteFilePath &&
+      sys::path::is_relative(IncludeDir))
+    sys::path::append(FilePath, CompDir);
+
+  // sys::path::append skips empty strings.
+  sys::path::append(FilePath, IncludeDir, FileName);
   Result = FilePath.str();
   return true;
 }
+
+bool
+DWARFDebugLine::LineTable::getFileLineInfoForAddress(uint64_t Address,
+                                                     const char *CompDir,
+                                                     FileLineInfoKind Kind,
+                                                     DILineInfo &Result) const {
+  // Get the index of row we're looking for in the line table.
+  uint32_t RowIndex = lookupAddress(Address);
+  if (RowIndex == -1U)
+    return false;
+  // Take file number and line/column from the row.
+  const auto &Row = Rows[RowIndex];
+  if (!getFileNameByIndex(Row.File, CompDir, Kind, Result.FileName))
+    return false;
+  Result.Line = Row.Line;
+  Result.Column = Row.Column;
+  return true;
+}
diff --git a/lib/DebugInfo/DWARFDebugLine.h b/lib/DebugInfo/DWARFDebugLine.h
index c7b7ec2..7a6f1bd 100644
--- a/lib/DebugInfo/DWARFDebugLine.h
+++ b/lib/DebugInfo/DWARFDebugLine.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGLINE_H
-#define LLVM_DEBUGINFO_DWARFDEBUGLINE_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGLINE_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGLINE_H
 
 #include "DWARFRelocMap.h"
 #include "llvm/DebugInfo/DIContext.h"
@@ -179,10 +179,16 @@ public:
 
     // Extracts filename by its index in filename table in prologue.
     // Returns true on success.
-    bool getFileNameByIndex(uint64_t FileIndex,
+    bool getFileNameByIndex(uint64_t FileIndex, const char *CompDir,
                             DILineInfoSpecifier::FileLineInfoKind Kind,
                             std::string &Result) const;
 
+    // Fills the Result argument with the file and line information
+    // corresponding to Address. Returns true on success.
+    bool getFileLineInfoForAddress(uint64_t Address, const char *CompDir, 
+                                   DILineInfoSpecifier::FileLineInfoKind Kind,
+                                   DILineInfo &Result) const;
+
     void dump(raw_ostream &OS) const;
     void clear();
 
diff --git a/lib/DebugInfo/DWARFDebugLoc.h b/lib/DebugInfo/DWARFDebugLoc.h
index 663acbb4..50110b3 100644
--- a/lib/DebugInfo/DWARFDebugLoc.h
+++ b/lib/DebugInfo/DWARFDebugLoc.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGLOC_H
-#define LLVM_DEBUGINFO_DWARFDEBUGLOC_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGLOC_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGLOC_H
 
 #include "DWARFRelocMap.h"
 #include "llvm/ADT/SmallVector.h"
diff --git a/lib/DebugInfo/DWARFDebugRangeList.h b/lib/DebugInfo/DWARFDebugRangeList.h
index 587b550..4ee3bda 100644
--- a/lib/DebugInfo/DWARFDebugRangeList.h
+++ b/lib/DebugInfo/DWARFDebugRangeList.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFDEBUGRANGELIST_H
-#define LLVM_DEBUGINFO_DWARFDEBUGRANGELIST_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFDEBUGRANGELIST_H
+#define LLVM_LIB_DEBUGINFO_DWARFDEBUGRANGELIST_H
 
 #include "llvm/Support/DataExtractor.h"
 #include <vector>
diff --git a/lib/DebugInfo/DWARFFormValue.cpp b/lib/DebugInfo/DWARFFormValue.cpp
index 8d0f966..69b9771 100644
--- a/lib/DebugInfo/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARFFormValue.cpp
@@ -139,6 +139,8 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
     switch (Form) {
     case DW_FORM_addr:
     case DW_FORM_ref_addr: {
+      if (!cu)
+        return false;
       uint16_t AddrSize =
           (Form == DW_FORM_addr)
               ? cu->getAddressByteSize()
@@ -179,8 +181,10 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
       break;
     case DW_FORM_data4:
     case DW_FORM_ref4: {
-      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr);
       Value.uval = data.getU32(offset_ptr);
+      if (!cu)
+        break;
+      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr-4);
       if (AI != cu->getRelocMap()->end())
         Value.uval += AI->second.second;
       break;
@@ -193,13 +197,12 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
       Value.sval = data.getSLEB128(offset_ptr);
       break;
     case DW_FORM_strp: {
-      RelocAddrMap::const_iterator AI
-        = cu->getRelocMap()->find(*offset_ptr);
-      if (AI != cu->getRelocMap()->end()) {
-        const std::pair<uint8_t, int64_t> &R = AI->second;
-        Value.uval = data.getU32(offset_ptr) + R.second;
-      } else
-        Value.uval = data.getU32(offset_ptr);
+      Value.uval = data.getU32(offset_ptr);
+      if (!cu)
+        break;
+      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr-4);
+      if (AI != cu->getRelocMap()->end())
+        Value.uval += AI->second.second;
       break;
     }
     case DW_FORM_udata:
@@ -215,13 +218,12 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
       break;
     case DW_FORM_sec_offset: {
       // FIXME: This is 64-bit for DWARF64.
-      RelocAddrMap::const_iterator AI
-        = cu->getRelocMap()->find(*offset_ptr);
-      if (AI != cu->getRelocMap()->end()) {
-        const std::pair<uint8_t, int64_t> &R = AI->second;
-        Value.uval = data.getU32(offset_ptr) + R.second;
-      } else
-        Value.uval = data.getU32(offset_ptr);
+      Value.uval = data.getU32(offset_ptr);
+      if (!cu)
+        break;
+      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr-4);
+      if (AI != cu->getRelocMap()->end())
+        Value.uval +=  AI->second.second;
       break;
     }
     case DW_FORM_flag_present:
@@ -360,8 +362,6 @@ DWARFFormValue::skipValue(uint16_t form, DataExtractor debug_info_data,
 
 void
 DWARFFormValue::dump(raw_ostream &OS, const DWARFUnit *cu) const {
-  DataExtractor debug_str_data(cu->getStringSection(), true, 0);
-  DataExtractor debug_str_offset_data(cu->getStringOffsetSection(), true, 0);
   uint64_t uvalue = Value.uval;
   bool cu_relative_offset = false;
 
@@ -543,7 +543,15 @@ Optional<uint64_t> DWARFFormValue::getAsSectionOffset() const {
 }
 
 Optional<uint64_t> DWARFFormValue::getAsUnsignedConstant() const {
-  if (!isFormClass(FC_Constant) || Form == DW_FORM_sdata)
+  if ((!isFormClass(FC_Constant) && !isFormClass(FC_Flag))
+      || Form == DW_FORM_sdata)
     return None;
   return Value.uval;
 }
+
+Optional<ArrayRef<uint8_t>> DWARFFormValue::getAsBlock() const {
+  if (!isFormClass(FC_Block) && !isFormClass(FC_Exprloc))
+    return None;
+  return ArrayRef<uint8_t>(Value.data, Value.uval);
+}
+
diff --git a/lib/DebugInfo/DWARFRelocMap.h b/lib/DebugInfo/DWARFRelocMap.h
index 6929e36..d7fe303 100644
--- a/lib/DebugInfo/DWARFRelocMap.h
+++ b/lib/DebugInfo/DWARFRelocMap.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFRELOCMAP_H
-#define LLVM_DEBUGINFO_DWARFRELOCMAP_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFRELOCMAP_H
+#define LLVM_LIB_DEBUGINFO_DWARFRELOCMAP_H
 
 #include "llvm/ADT/DenseMap.h"
 
@@ -18,5 +18,5 @@ typedef DenseMap<uint64_t, std::pair<uint8_t, int64_t> > RelocAddrMap;
 
 } // namespace llvm
 
-#endif // LLVM_DEBUGINFO_DWARFRELOCMAP_H
+#endif
 
diff --git a/lib/DebugInfo/DWARFSection.h b/lib/DebugInfo/DWARFSection.h
new file mode 100644
index 0000000..3aaf0ff
--- /dev/null
+++ b/lib/DebugInfo/DWARFSection.h
@@ -0,0 +1,24 @@
+//===-- DWARFSection.h ------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DEBUGINFO_DWARFSECTION_H
+#define LLVM_LIB_DEBUGINFO_DWARFSECTION_H
+
+#include "DWARFRelocMap.h"
+
+namespace llvm {
+
+struct DWARFSection {
+  StringRef Data;
+  RelocAddrMap Relocs;
+};
+
+}
+
+#endif
diff --git a/lib/DebugInfo/DWARFTypeUnit.h b/lib/DebugInfo/DWARFTypeUnit.h
index cf773b8..7471b5a 100644
--- a/lib/DebugInfo/DWARFTypeUnit.h
+++ b/lib/DebugInfo/DWARFTypeUnit.h
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFTYPEUNIT_H
-#define LLVM_DEBUGINFO_DWARFTYPEUNIT_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFTYPEUNIT_H
+#define LLVM_LIB_DEBUGINFO_DWARFTYPEUNIT_H
 
 #include "DWARFUnit.h"
 
@@ -19,10 +19,11 @@ private:
   uint64_t TypeHash;
   uint32_t TypeOffset;
 public:
-  DWARFTypeUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef RS,
-                StringRef SS, StringRef SOS, StringRef AOS,
-                const RelocAddrMap *M, bool LE)
-      : DWARFUnit(DA, IS, RS, SS, SOS, AOS, M, LE) {}
+  DWARFTypeUnit(DWARFContext &Context, const DWARFSection &Section,
+                const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                StringRef SOS, StringRef AOS, bool LE,
+                const DWARFUnitSectionBase &UnitSection)
+      : DWARFUnit(Context, Section, DA, RS, SS, SOS, AOS, LE, UnitSection) {}
   uint32_t getHeaderSize() const override {
     return DWARFUnit::getHeaderSize() + 12;
   }
diff --git a/lib/DebugInfo/DWARFUnit.cpp b/lib/DebugInfo/DWARFUnit.cpp
index 39d0a0f..82c4529 100644
--- a/lib/DebugInfo/DWARFUnit.cpp
+++ b/lib/DebugInfo/DWARFUnit.cpp
@@ -17,12 +17,26 @@
 using namespace llvm;
 using namespace dwarf;
 
-DWARFUnit::DWARFUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef RS,
-                     StringRef SS, StringRef SOS, StringRef AOS,
-                     const RelocAddrMap *M, bool LE)
-    : Abbrev(DA), InfoSection(IS), RangeSection(RS), StringSection(SS),
-      StringOffsetSection(SOS), AddrOffsetSection(AOS), RelocMap(M),
-      isLittleEndian(LE) {
+void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
+  parseImpl(C, Section, C.getDebugAbbrev(), C.getRangeSection(),
+            C.getStringSection(), StringRef(), C.getAddrSection(),
+            C.isLittleEndian());
+}
+
+void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
+                                    const DWARFSection &DWOSection) {
+  parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), C.getRangeDWOSection(),
+            C.getStringDWOSection(), C.getStringOffsetDWOSection(),
+            C.getAddrSection(), C.isLittleEndian());
+}
+
+DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
+                     const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                     StringRef SOS, StringRef AOS, bool LE,
+                     const DWARFUnitSectionBase &UnitSection)
+    : Context(DC), InfoSection(Section), Abbrev(DA), RangeSection(RS),
+      StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
+      isLittleEndian(LE), UnitSection(UnitSection) {
   clear();
 }
 
@@ -235,10 +249,14 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
   return DieArray.size();
 }
 
-DWARFUnit::DWOHolder::DWOHolder(object::ObjectFile *DWOFile)
-    : DWOFile(DWOFile),
-      DWOContext(cast<DWARFContext>(DIContext::getDWARFContext(DWOFile))),
-      DWOU(nullptr) {
+DWARFUnit::DWOHolder::DWOHolder(StringRef DWOPath)
+    : DWOFile(), DWOContext(), DWOU(nullptr) {
+  auto Obj = object::ObjectFile::createObjectFile(DWOPath);
+  if (!Obj)
+    return;
+  DWOFile = std::move(Obj.get());
+  DWOContext.reset(
+      cast<DWARFContext>(DIContext::getDWARFContext(*DWOFile.getBinary())));
   if (DWOContext->getNumDWOCompileUnits() > 0)
     DWOU = DWOContext->getDWOCompileUnitAtIndex(0);
 }
@@ -260,12 +278,7 @@ bool DWARFUnit::parseDWO() {
     sys::path::append(AbsolutePath, CompilationDir);
   }
   sys::path::append(AbsolutePath, DWOFileName);
-  ErrorOr<object::ObjectFile *> DWOFile =
-      object::ObjectFile::createObjectFile(AbsolutePath);
-  if (!DWOFile)
-    return false;
-  // Reset DWOHolder.
-  DWO.reset(new DWOHolder(DWOFile.get()));
+  DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.
   if (!DWOCU || DWOCU->getDWOId() != getDWOId()) {
diff --git a/lib/DebugInfo/DWARFUnit.h b/lib/DebugInfo/DWARFUnit.h
index 471da36..786f00f 100644
--- a/lib/DebugInfo/DWARFUnit.h
+++ b/lib/DebugInfo/DWARFUnit.h
@@ -7,13 +7,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_DEBUGINFO_DWARFUNIT_H
-#define LLVM_DEBUGINFO_DWARFUNIT_H
+#ifndef LLVM_LIB_DEBUGINFO_DWARFUNIT_H
+#define LLVM_LIB_DEBUGINFO_DWARFUNIT_H
 
 #include "DWARFDebugAbbrev.h"
 #include "DWARFDebugInfoEntry.h"
 #include "DWARFDebugRangeList.h"
 #include "DWARFRelocMap.h"
+#include "DWARFSection.h"
 #include <vector>
 
 namespace llvm {
@@ -22,21 +23,96 @@ namespace object {
 class ObjectFile;
 }
 
+class DWARFContext;
 class DWARFDebugAbbrev;
+class DWARFUnit;
 class StringRef;
 class raw_ostream;
 
+/// Base class for all DWARFUnitSection classes. This provides the
+/// functionality common to all unit types.
+class DWARFUnitSectionBase {
+public:
+  /// Returns the Unit that contains the given section offset in the
+  /// same section this Unit originated from.
+  virtual DWARFUnit *getUnitForOffset(uint32_t Offset) const = 0;
+
+  void parse(DWARFContext &C, const DWARFSection &Section);
+  void parseDWO(DWARFContext &C, const DWARFSection &DWOSection);
+
+protected:
+  virtual void parseImpl(DWARFContext &Context, const DWARFSection &Section,
+                         const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                         StringRef SOS, StringRef AOS, bool isLittleEndian) = 0;
+
+  ~DWARFUnitSectionBase() {}
+};
+
+/// Concrete instance of DWARFUnitSection, specialized for one Unit type.
+template<typename UnitType>
+class DWARFUnitSection final : public SmallVector<std::unique_ptr<UnitType>, 1>,
+                               public DWARFUnitSectionBase {
+
+  struct UnitOffsetComparator {
+    bool operator()(uint32_t LHS,
+                    const std::unique_ptr<UnitType> &RHS) const {
+      return LHS < RHS->getNextUnitOffset();
+    }
+  };
+
+  bool Parsed;
+
+public:
+  DWARFUnitSection() : Parsed(false) {}
+  DWARFUnitSection(DWARFUnitSection &&DUS) :
+    SmallVector<std::unique_ptr<UnitType>, 1>(std::move(DUS)), Parsed(DUS.Parsed) {}
+
+  typedef llvm::SmallVectorImpl<std::unique_ptr<UnitType>> UnitVector;
+  typedef typename UnitVector::iterator iterator;
+  typedef llvm::iterator_range<typename UnitVector::iterator> iterator_range;
+
+  UnitType *getUnitForOffset(uint32_t Offset) const override {
+    auto *CU = std::upper_bound(this->begin(), this->end(), Offset,
+                                UnitOffsetComparator());
+    if (CU != this->end())
+      return CU->get();
+    return nullptr;
+  }
+
+private:
+  void parseImpl(DWARFContext &Context, const DWARFSection &Section,
+                 const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+                 StringRef SOS, StringRef AOS, bool LE) override {
+    if (Parsed)
+      return;
+    DataExtractor Data(Section.Data, LE, 0);
+    uint32_t Offset = 0;
+    while (Data.isValidOffset(Offset)) {
+      auto U = llvm::make_unique<UnitType>(Context, Section, DA, RS, SS, SOS,
+                                           AOS, LE, *this);
+      if (!U->extract(Data, &Offset))
+        break;
+      this->push_back(std::move(U));
+      Offset = this->back()->getNextUnitOffset();
+    }
+    Parsed = true;
+  }
+};
+
 class DWARFUnit {
+  DWARFContext &Context;
+  // Section containing this DWARFUnit.
+  const DWARFSection &InfoSection;
+
   const DWARFDebugAbbrev *Abbrev;
-  StringRef InfoSection;
   StringRef RangeSection;
   uint32_t RangeSectionBase;
   StringRef StringSection;
   StringRef StringOffsetSection;
   StringRef AddrOffsetSection;
   uint32_t AddrOffsetSectionBase;
-  const RelocAddrMap *RelocMap;
   bool isLittleEndian;
+  const DWARFUnitSectionBase &UnitSection;
 
   uint32_t Offset;
   uint32_t Length;
@@ -48,11 +124,11 @@ class DWARFUnit {
   std::vector<DWARFDebugInfoEntryMinimal> DieArray;
 
   class DWOHolder {
-    std::unique_ptr<object::ObjectFile> DWOFile;
+    object::OwningBinary<object::ObjectFile> DWOFile;
     std::unique_ptr<DWARFContext> DWOContext;
     DWARFUnit *DWOU;
   public:
-    DWOHolder(object::ObjectFile *DWOFile);
+    DWOHolder(StringRef DWOPath);
     DWARFUnit *getUnit() const { return DWOU; }
   };
   std::unique_ptr<DWOHolder> DWO;
@@ -63,12 +139,15 @@ protected:
   virtual uint32_t getHeaderSize() const { return 11; }
 
 public:
-  DWARFUnit(const DWARFDebugAbbrev *DA, StringRef IS, StringRef RS,
-            StringRef SS, StringRef SOS, StringRef AOS, const RelocAddrMap *M,
-            bool LE);
+  DWARFUnit(DWARFContext &Context, const DWARFSection &Section,
+            const DWARFDebugAbbrev *DA, StringRef RS, StringRef SS,
+            StringRef SOS, StringRef AOS, bool LE,
+            const DWARFUnitSectionBase &UnitSection);
 
   virtual ~DWARFUnit();
 
+  DWARFContext& getContext() const { return Context; }
+
   StringRef getStringSection() const { return StringSection; }
   StringRef getStringOffsetSection() const { return StringOffsetSection; }
   void setAddrOffsetSection(StringRef AOS, uint32_t Base) {
@@ -85,13 +164,13 @@ public:
   bool getStringOffsetSectionItem(uint32_t Index, uint32_t &Result) const;
 
   DataExtractor getDebugInfoExtractor() const {
-    return DataExtractor(InfoSection, isLittleEndian, AddrSize);
+    return DataExtractor(InfoSection.Data, isLittleEndian, AddrSize);
   }
   DataExtractor getStringExtractor() const {
     return DataExtractor(StringSection, false, 0);
   }
 
-  const RelocAddrMap *getRelocMap() const { return RelocMap; }
+  const RelocAddrMap *getRelocMap() const { return &InfoSection.Relocs; }
 
   bool extract(DataExtractor debug_info, uint32_t* offset_ptr);
 
@@ -131,6 +210,9 @@ public:
   /// chain is valid as long as parsed compile unit DIEs are not cleared.
   DWARFDebugInfoEntryInlinedChain getInlinedChainForAddress(uint64_t Address);
 
+  /// getUnitSection - Return the DWARFUnitSection containing this unit.
+  const DWARFUnitSectionBase &getUnitSection() const { return UnitSection; }
+
 private:
   /// Size in bytes of the .debug_info data associated with this compile unit.
   size_t getDebugInfoSize() const { return Length + 4 - getHeaderSize(); }