diff --git a/tools/dsymutil/DwarfLinker.cpp b/tools/dsymutil/DwarfLinker.cpp
index 04dca726e4a..4e3dc528178 100644
--- a/tools/dsymutil/DwarfLinker.cpp
+++ b/tools/dsymutil/DwarfLinker.cpp
@@ -10,6 +10,7 @@
 #include "BinaryHolder.h"
 #include "DebugMap.h"
 #include "dsymutil.h"
+#include "llvm/ADT/IntervalMap.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CodeGen/AsmPrinter.h"
@@ -49,6 +50,11 @@ bool error(const Twine &Error, const Twine &Context) {
   return false;
 }
 
+template <typename KeyT, typename ValT>
+using HalfOpenIntervalMap =
+    IntervalMap<KeyT, ValT, IntervalMapImpl::NodeSizer<KeyT, ValT>::LeafSize,
+                IntervalMapHalfOpenInfo<KeyT>>;
+
 /// \brief Stores all information relating to a compile unit, be it in
 /// its original instance in the object file to its brand new cloned
 /// and linked DIE tree.
@@ -63,15 +69,19 @@ public:
     bool InDebugMap;    ///< Was this DIE's entity found in the map?
   };
 
-  CompileUnit(DWARFUnit &OrigUnit) : OrigUnit(OrigUnit) {
+  CompileUnit(DWARFUnit &OrigUnit)
+      : OrigUnit(OrigUnit), RangeAlloc(), Ranges(RangeAlloc) {
     Info.resize(OrigUnit.getNumDIEs());
   }
 
-  // Workaround MSVC not supporting implicit move ops
   CompileUnit(CompileUnit &&RHS)
       : OrigUnit(RHS.OrigUnit), Info(std::move(RHS.Info)),
         CUDie(std::move(RHS.CUDie)), StartOffset(RHS.StartOffset),
-        NextUnitOffset(RHS.NextUnitOffset) {}
+        NextUnitOffset(RHS.NextUnitOffset), RangeAlloc(), Ranges(RangeAlloc) {
+    // The CompileUnit container has been 'reserve()'d with the right
+    // size. We cannot move the IntervalMap anyway.
+    llvm_unreachable("CompileUnits should not be moved.");
+  }
 
   DWARFUnit &getOrigUnit() const { return OrigUnit; }
 
@@ -100,6 +110,10 @@ public:
   /// \brief Apply all fixups recored by noteForwardReference().
   void fixupForwardReferences();
 
+  /// \brief Add a function range [\p LowPC, \p HighPC) that is
+  /// relocatad by applying offset \p PCOffset.
+  void addFunctionRange(uint64_t LowPC, uint64_t HighPC, int64_t PCOffset);
+
 private:
   DWARFUnit &OrigUnit;
   std::vector<DIEInfo> Info;  ///< DIE info indexed by DIE index.
@@ -115,6 +129,12 @@ private:
   /// cloning because for forward refences the target DIE's offset isn't
   /// known you emit the reference attribute.
   std::vector<std::pair<DIE *, DIEInteger *>> ForwardDIEReferences;
+
+  HalfOpenIntervalMap<uint64_t, int64_t>::Allocator RangeAlloc;
+  /// \brief The ranges in that interval map are the PC ranges for
+  /// functions in this unit, associated with the PC offset to apply
+  /// to the addresses to get the linked address.
+  HalfOpenIntervalMap<uint64_t, int64_t> Ranges;
 };
 
 uint64_t CompileUnit::computeNextUnitOffset() {
@@ -138,6 +158,11 @@ void CompileUnit::fixupForwardReferences() {
     Ref.second->setValue(Ref.first->getOffset() + getStartOffset());
 }
 
+void CompileUnit::addFunctionRange(uint64_t LowPC, uint64_t HighPC,
+                                   int64_t PCOffset) {
+  Ranges.insert(LowPC, HighPC, PCOffset);
+}
+
 /// \brief A string table that doesn't need relocations.
 ///
 /// We are doing a final link, no need for a string table that
@@ -944,7 +969,25 @@ unsigned DwarfLinker::shouldKeepSubprogramDIE(
   if (Options.Verbose)
     DIE.dump(outs(), const_cast<DWARFUnit *>(&OrigUnit), 0, 8 /* Indent */);
 
-  return Flags | TF_Keep;
+  Flags |= TF_Keep;
+
+  DWARFFormValue HighPcValue;
+  if (!DIE.getAttributeValue(&OrigUnit, dwarf::DW_AT_high_pc, HighPcValue)) {
+    reportWarning("Function without high_pc. Range will be discarded.\n",
+                  &OrigUnit, &DIE);
+    return Flags;
+  }
+
+  uint64_t HighPc;
+  if (HighPcValue.isFormClass(DWARFFormValue::FC_Address)) {
+    HighPc = *HighPcValue.getAsAddress(&OrigUnit);
+  } else {
+    assert(HighPcValue.isFormClass(DWARFFormValue::FC_Constant));
+    HighPc = LowPc + *HighPcValue.getAsUnsignedConstant();
+  }
+
+  Unit.addFunctionRange(LowPc, HighPc, MyInfo.AddrAdjust);
+  return Flags;
 }
 
 /// \brief Check if a DIE should be kept.