Index: llvm/include/llvm/ProfileData/SampleProf.h
===================================================================
--- llvm/include/llvm/ProfileData/SampleProf.h
+++ llvm/include/llvm/ProfileData/SampleProf.h
@@ -18,6 +18,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Module.h"
@@ -182,10 +183,16 @@
 
   /// Merge the samples in \p Other into this record.
   /// Optionally scale sample counts by \p Weight.
-  sampleprof_error merge(const SampleRecord &Other, uint64_t Weight = 1) {
+  sampleprof_error merge(const SampleRecord &Other,
+                         StringSet<> *FunctionNames = nullptr,
+                         uint64_t Weight = 1) {
     sampleprof_error Result = addSamples(Other.getSamples(), Weight);
     for (const auto &I : Other.getCallTargets()) {
-      MergeResult(Result, addCalledTarget(I.first(), I.second, Weight));
+      StringRef FName = I.first();
+      if (FunctionNames) {
+        FName = FunctionNames->insert(FName).first->first();
+      }
+      MergeResult(Result, addCalledTarget(FName, I.second, Weight));
     }
     return Result;
   }
@@ -356,7 +363,9 @@
 
   /// Merge the samples in \p Other into this one.
   /// Optionally scale samples by \p Weight.
-  sampleprof_error merge(const FunctionSamples &Other, uint64_t Weight = 1) {
+  sampleprof_error merge(const FunctionSamples &Other,
+                         StringSet<> *FunctionNames = nullptr,
+                         uint64_t Weight = 1) {
     sampleprof_error Result = sampleprof_error::success;
     Name = Other.getName();
     MergeResult(Result, addTotalSamples(Other.getTotalSamples(), Weight));
@@ -364,13 +373,20 @@
     for (const auto &I : Other.getBodySamples()) {
       const LineLocation &Loc = I.first;
       const SampleRecord &Rec = I.second;
-      MergeResult(Result, BodySamples[Loc].merge(Rec, Weight));
+      MergeResult(Result, BodySamples[Loc].merge(Rec, FunctionNames, Weight));
     }
     for (const auto &I : Other.getCallsiteSamples()) {
       const LineLocation &Loc = I.first;
       FunctionSamplesMap &FSMap = functionSamplesAt(Loc);
-      for (const auto &Rec : I.second)
-        MergeResult(Result, FSMap[Rec.first].merge(Rec.second, Weight));
+      for (const auto &Rec : I.second) {
+        if (FunctionNames) {
+          StringRef FName = Rec.second.getName();
+          FName = FunctionNames->insert(FName).first->first();
+          const_cast<FunctionSamples &>(Rec.second).setName(FName);
+        }
+        MergeResult(Result,
+                    FSMap[Rec.first].merge(Rec.second, FunctionNames, Weight));
+      }
     }
     return Result;
   }
Index: llvm/tools/llvm-profdata/llvm-profdata.cpp
===================================================================
--- llvm/tools/llvm-profdata/llvm-profdata.cpp
+++ llvm/tools/llvm-profdata/llvm-profdata.cpp
@@ -13,6 +13,7 @@
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/ProfileData/InstrProfReader.h"
 #include "llvm/ProfileData/InstrProfWriter.h"
@@ -440,19 +441,14 @@
 
   auto Writer = std::move(WriterOrErr.get());
   StringMap<FunctionSamples> ProfileMap;
-  SmallVector<std::unique_ptr<sampleprof::SampleProfileReader>, 5> Readers;
+  StringSet<> FunctionNames;
   LLVMContext Context;
   for (const auto &Input : Inputs) {
     auto ReaderOrErr = SampleProfileReader::create(Input.Filename, Context);
     if (std::error_code EC = ReaderOrErr.getError())
       exitWithErrorCode(EC, Input.Filename);
 
-    // We need to keep the readers around until after all the files are
-    // read so that we do not lose the function names stored in each
-    // reader's memory. The function names are needed to write out the
-    // merged profile map.
-    Readers.push_back(std::move(ReaderOrErr.get()));
-    const auto Reader = Readers.back().get();
+    const auto &Reader = ReaderOrErr.get();
     if (std::error_code EC = Reader->read())
       exitWithErrorCode(EC, Input.Filename);
 
@@ -466,7 +462,10 @@
                    : FunctionSamples();
       FunctionSamples &Samples = Remapper ? Remapped : I->second;
       StringRef FName = Samples.getName();
-      MergeResult(Result, ProfileMap[FName].merge(Samples, Input.Weight));
+      FName = FunctionNames.insert(FName).first->first();
+      Samples.setName(FName);
+      MergeResult(Result, ProfileMap[FName].merge(Samples, &FunctionNames,
+                                                  Input.Weight));
       if (Result != sampleprof_error::success) {
         std::error_code EC = make_error_code(Result);
         handleMergeWriterError(errorCodeToError(EC), Input.Filename, FName);