Index: include/llvm/DebugInfo/DWARF/DWARFDebugRangeList.h
===================================================================
--- include/llvm/DebugInfo/DWARF/DWARFDebugRangeList.h
+++ include/llvm/DebugInfo/DWARF/DWARFDebugRangeList.h
@@ -18,6 +18,7 @@
 
 namespace llvm {
 
+struct BaseAddress;
 class raw_ostream;
 
 struct DWARFAddressRange {
@@ -85,7 +86,8 @@
   /// getAbsoluteRanges - Returns absolute address ranges defined by this range
   /// list. Has to be passed base address of the compile unit referencing this
   /// range list.
-  DWARFAddressRangesVector getAbsoluteRanges(uint64_t BaseAddress) const;
+  DWARFAddressRangesVector
+  getAbsoluteRanges(llvm::Optional<BaseAddress> BaseAddr) const;
 };
 
 } // end namespace llvm
Index: include/llvm/DebugInfo/DWARF/DWARFUnit.h
===================================================================
--- include/llvm/DebugInfo/DWARF/DWARFUnit.h
+++ include/llvm/DebugInfo/DWARF/DWARFUnit.h
@@ -110,6 +110,11 @@
   }
 };
 
+struct BaseAddress {
+  uint64_t Address;
+  uint64_t SectionIndex;
+};
+
 class DWARFUnit {
   DWARFContext &Context;
   /// Section containing this DWARFUnit.
@@ -135,7 +140,7 @@
   uint32_t Length;
   const DWARFAbbreviationDeclarationSet *Abbrevs;
   uint8_t UnitType;
-  uint64_t BaseAddr;
+  llvm::Optional<BaseAddress> BaseAddr;
   /// The compile unit debug information entry items.
   std::vector<DWARFDebugInfoEntry> DieArray;
 
@@ -259,10 +264,12 @@
     llvm_unreachable("Invalid UnitType.");
   }
 
-  uint64_t getBaseAddress() const { return BaseAddr; }
+  llvm::Optional<BaseAddress> getBaseAddress() const { return BaseAddr; }
 
-  void setBaseAddress(uint64_t base_addr) {
-    BaseAddr = base_addr;
+  void setBaseAddress(BaseAddress BaseAddr) {
+    if (!BaseAddr.Address && BaseAddr.SectionIndex == -1ULL)
+      return;
+    this->BaseAddr = BaseAddr;
   }
 
   DWARFDie getUnitDIE(bool ExtractUnitDIEOnly = true) {
Index: lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
+++ lib/DebugInfo/DWARF/DWARFDebugRangeList.cpp
@@ -63,16 +63,28 @@
   OS << format("%08x <End of list>\n", Offset);
 }
 
-DWARFAddressRangesVector
-DWARFDebugRangeList::getAbsoluteRanges(uint64_t BaseAddress) const {
+DWARFAddressRangesVector DWARFDebugRangeList::getAbsoluteRanges(
+    llvm::Optional<BaseAddress> BaseAddr) const {
   DWARFAddressRangesVector Res;
   for (const RangeListEntry &RLE : Entries) {
     if (RLE.isBaseAddressSelectionEntry(AddressSize)) {
-      BaseAddress = RLE.EndAddress;
-    } else {
-      Res.push_back({BaseAddress + RLE.StartAddress,
-                     BaseAddress + RLE.EndAddress, RLE.SectionIndex});
+      BaseAddr = { RLE.EndAddress, RLE.SectionIndex };
+      continue;
     }
+
+    DWARFAddressRange E;
+    E.LowPC = RLE.StartAddress;
+    E.HighPC = RLE.EndAddress;
+    E.SectionIndex = RLE.SectionIndex;
+    // Base address of a range list entry is determined by the closest preceding
+    // base address selection entry in the same range list. It defaults to the
+    // base address of the compilation unit if there is no such entry.
+    if (BaseAddr) {
+      E.LowPC += BaseAddr->Address;
+      E.HighPC += BaseAddr->Address;
+      E.SectionIndex = BaseAddr->SectionIndex;
+    }
+    Res.push_back(E);
   }
   return Res;
 }
Index: lib/DebugInfo/DWARF/DWARFFormValue.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFFormValue.cpp
+++ lib/DebugInfo/DWARF/DWARFFormValue.cpp
@@ -292,6 +292,7 @@
         return false;
       uint16_t Size = (Form == DW_FORM_addr) ? U->getAddressByteSize()
                                              : U->getRefAddrByteSize();
+      Value.SectionIndex = -1ULL;
       Value.uval = Data.getRelocatedValue(Size, OffsetPtr, &Value.SectionIndex);
       break;
     }
Index: lib/DebugInfo/DWARF/DWARFUnit.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -160,7 +160,7 @@
   Length = 0;
   Abbrevs = nullptr;
   FormParams = DWARFFormParams({0, 0, DWARF32});
-  BaseAddr = 0;
+  BaseAddr.reset();
   RangeSectionBase = 0;
   AddrOffsetSectionBase = 0;
   clearDIEs(false);
@@ -242,9 +242,10 @@
   // If CU DIE was just parsed, copy several attribute values from it.
   if (!HasCUDie) {
     DWARFDie UnitDie = getUnitDIE();
-    auto BaseAddr = toAddress(UnitDie.find({DW_AT_low_pc, DW_AT_entry_pc}));
-    if (BaseAddr)
-      setBaseAddress(*BaseAddr);
+    if (Optional<DWARFFormValue> PC =
+            UnitDie.find({DW_AT_low_pc, DW_AT_entry_pc}))
+      if (Optional<uint64_t> Addr = PC->getAsAddress())
+        setBaseAddress({*Addr, PC->getSectionIndex()});
     if (!isDWO) {
       assert(AddrOffsetSectionBase == 0);
       assert(RangeSectionBase == 0);