Index: llvm/trunk/lib/DebugInfo/DWARFContext.cpp
===================================================================
--- llvm/trunk/lib/DebugInfo/DWARFContext.cpp
+++ llvm/trunk/lib/DebugInfo/DWARFContext.cpp
@@ -314,84 +314,28 @@
 }
 
 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(*this,
-        getDebugAbbrev(), getInfoSection().Data, getRangeSection(),
-        getStringSection(), StringRef(), getAddrSection(),
-        &getInfoSection().Relocs, isLittleEndian(), CUs));
-    if (!CU->extract(DIData, &offset)) {
-      break;
-    }
-    CUs.push_back(std::move(CU));
-    offset = CUs.back()->getNextUnitOffset();
-  }
+  CUs.parse(*this, getInfoSection().Data, getInfoSection().Relocs);
 }
 
 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);
     TUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
-    auto &TUS = TUs.back();
-    while (DIData.isValidOffset(offset)) {
-      std::unique_ptr<DWARFTypeUnit> TU(new DWARFTypeUnit(*this,
-           getDebugAbbrev(), I.second.Data, getRangeSection(),
-           getStringSection(), StringRef(), getAddrSection(),
-           &I.second.Relocs, isLittleEndian(), TUS));
-      if (!TU->extract(DIData, &offset))
-        break;
-      TUS.push_back(std::move(TU));
-      offset = TUS.back()->getNextUnitOffset();
-    }
+    TUs.back().parse(*this, I.second.Data, I.second.Relocs);
   }
 }
 
 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(*this,
-        getDebugAbbrevDWO(), getInfoDWOSection().Data, getRangeDWOSection(),
-        getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
-        &getInfoDWOSection().Relocs, isLittleEndian(), DWOCUs));
-    if (!DWOCU->extract(DIData, &offset)) {
-      break;
-    }
-    DWOCUs.push_back(std::move(DWOCU));
-    offset = DWOCUs.back()->getNextUnitOffset();
-  }
+  DWOCUs.parseDWO(*this, getInfoDWOSection().Data, getInfoDWOSection().Relocs);
 }
 
 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);
     DWOTUs.push_back(DWARFUnitSection<DWARFTypeUnit>());
-    auto &TUS = DWOTUs.back();
-    while (DIData.isValidOffset(offset)) {
-      std::unique_ptr<DWARFTypeUnit> TU(new DWARFTypeUnit(*this,
-          getDebugAbbrevDWO(), I.second.Data, getRangeDWOSection(),
-          getStringDWOSection(), getStringOffsetDWOSection(), getAddrSection(),
-          &I.second.Relocs, isLittleEndian(), TUS));
-      if (!TU->extract(DIData, &offset))
-        break;
-      TUS.push_back(std::move(TU));
-      offset = TUS.back()->getNextUnitOffset();
-    }
+    DWOTUs.back().parseDWO(*this, I.second.Data, I.second.Relocs);
   }
 }
 
Index: llvm/trunk/lib/DebugInfo/DWARFUnit.h
===================================================================
--- llvm/trunk/lib/DebugInfo/DWARFUnit.h
+++ llvm/trunk/lib/DebugInfo/DWARFUnit.h
@@ -36,7 +36,15 @@
   /// same section this Unit originated from.
   virtual DWARFUnit *getUnitForOffset(uint32_t Offset) const = 0;
 
+  void parse(DWARFContext &C, StringRef SectionData, const RelocAddrMap &Map);
+  void parseDWO(DWARFContext &C, StringRef SectionData, const RelocAddrMap &Map);
+
 protected:
+  virtual void parseImpl(DWARFContext &Context, const DWARFDebugAbbrev *DA,
+                         StringRef Section, StringRef RS, StringRef SS,
+                         StringRef SOS, StringRef AOS, const RelocAddrMap &M,
+                         bool isLittleEndian) = 0;
+
   ~DWARFUnitSectionBase() {}
 };
 
@@ -52,10 +60,12 @@
     }
   };
 
+  bool Parsed;
+
 public:
-  DWARFUnitSection() {}
+  DWARFUnitSection() : Parsed(false) {}
   DWARFUnitSection(DWARFUnitSection &&DUS) :
-    SmallVector<std::unique_ptr<UnitType>, 1>(std::move(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;
@@ -68,6 +78,25 @@
       return CU->get();
     return nullptr;
   }
+
+ private:
+  void parseImpl(DWARFContext &Context, const DWARFDebugAbbrev *DA,
+                 StringRef Section, StringRef RS, StringRef SS, StringRef SOS,
+                 StringRef AOS, const RelocAddrMap &M, bool LE) override {
+    if (Parsed)
+      return;
+    DataExtractor Data(Section, LE, 0);
+    uint32_t Offset = 0;
+    while (Data.isValidOffset(Offset)) {
+      auto U = make_unique<UnitType>(Context, DA, Section, RS, SS, SOS, AOS, &M,
+                                     Data.isLittleEndian(), *this);
+      if (!U->extract(Data, &Offset))
+        break;
+      this->push_back(std::move(U));
+      Offset = this->back()->getNextUnitOffset();
+    }
+    Parsed = true;
+  }
 };
 
 class DWARFUnit {
Index: llvm/trunk/lib/DebugInfo/DWARFUnit.cpp
===================================================================
--- llvm/trunk/lib/DebugInfo/DWARFUnit.cpp
+++ llvm/trunk/lib/DebugInfo/DWARFUnit.cpp
@@ -17,6 +17,21 @@
 using namespace llvm;
 using namespace dwarf;
 
+
+void DWARFUnitSectionBase::parse(DWARFContext &C, StringRef SectionData,
+                                 const RelocAddrMap &Map) {
+  parseImpl(C, C.getDebugAbbrev(), SectionData, C.getRangeSection(),
+            C.getStringSection(), StringRef(), C.getAddrSection(), Map,
+            C.isLittleEndian());
+}
+
+void DWARFUnitSectionBase::parseDWO(DWARFContext &C, StringRef SectionData,
+                                    const RelocAddrMap &Map) {
+  parseImpl(C, C.getDebugAbbrevDWO(), SectionData, C.getRangeDWOSection(),
+            C.getStringDWOSection(), C.getStringOffsetDWOSection(),
+            C.getAddrSection(), Map, C.isLittleEndian());
+}
+
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFDebugAbbrev *DA,
                      StringRef IS, StringRef RS, StringRef SS, StringRef SOS,
                      StringRef AOS, const RelocAddrMap *M, bool LE,