Fix use-after-free with profile remapping.

We need to keep the underlying profile reader alive as long as the
profile data, because the profile data may contain StringRefs referring
to strings in the reader's name table.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349600 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ProfileData/SampleProfReader.h

@@ -548,6 +548,9 @@ public:
       : SampleProfileReader(std::move(B), C, Underlying->getFormat()) {
     Profiles = std::move(Underlying->getProfiles());
     Summary = takeSummary(*Underlying);
+    // Keep the underlying reader alive; the profile data may contain
+    // StringRefs referencing names in its name table.
+    UnderlyingReader = std::move(Underlying);
   }
 
   /// Create a remapped sample profile from the given remapping file and
@@ -569,6 +572,7 @@ public:
 private:
   SymbolRemappingReader Remappings;
   DenseMap<SymbolRemappingReader::Key, FunctionSamples*> SampleMap;
+  std::unique_ptr<SampleProfileReader> UnderlyingReader;
 };
 
 } // end namespace sampleprof

unittests/ProfileData/SampleProfTest.cpp

@@ -128,11 +128,15 @@ struct SampleProfTest : ::testing::Test {
 
     FunctionSamples *ReadFooSamples = Reader->getSamplesFor(FooName);
     ASSERT_TRUE(ReadFooSamples != nullptr);
+    if (Format != SampleProfileFormat::SPF_Compact_Binary)
+      ASSERT_EQ("_Z3fooi", ReadFooSamples->getName());
     ASSERT_EQ(7711u, ReadFooSamples->getTotalSamples());
     ASSERT_EQ(610u, ReadFooSamples->getHeadSamples());
 
     FunctionSamples *ReadBarSamples = Reader->getSamplesFor(BarName);
     ASSERT_TRUE(ReadBarSamples != nullptr);
+    if (Format != SampleProfileFormat::SPF_Compact_Binary)
+      ASSERT_EQ("_Z3bari", ReadBarSamples->getName());
     ASSERT_EQ(20301u, ReadBarSamples->getTotalSamples());
     ASSERT_EQ(1437u, ReadBarSamples->getHeadSamples());
     ErrorOr<SampleRecord::CallTargetMap> CTMap =