[PGO] Handle and report overflow during profile merge for all types of data

Summary: Surface counter overflow when merging profile data. Merging still occurs on overflow but counts saturate to the maximum representable value. Overflow is reported to the user.

Reviewers: davidxl, dnovillo, silvas

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D15547

llvm-svn: 255825

1 files changed, 30 insertions, 0 deletions

diff --git a/llvm/unittests/ProfileData/SampleProfTest.cpp b/llvm/unittests/ProfileData/SampleProfTest.cpp
index aa1144d7913..cc3c2f5306e 100644
--- a/llvm/unittests/ProfileData/SampleProfTest.cpp
+++ b/llvm/unittests/ProfileData/SampleProfTest.cpp
@@ -99,4 +99,34 @@ TEST_F(SampleProfTest, roundtrip_binary_profile) {
   testRoundTrip(SampleProfileFormat::SPF_Binary);
 }
 
+TEST_F(SampleProfTest, sample_overflow_saturation) {
+  const uint64_t Max = std::numeric_limits<uint64_t>::max();
+  sampleprof_error Result;
+
+  StringRef FooName("_Z3fooi");
+  FunctionSamples FooSamples;
+  Result = FooSamples.addTotalSamples(1);
+  ASSERT_EQ(Result, sampleprof_error::success);
+
+  Result = FooSamples.addHeadSamples(1);
+  ASSERT_EQ(Result, sampleprof_error::success);
+
+  Result = FooSamples.addBodySamples(10, 0, 1);
+  ASSERT_EQ(Result, sampleprof_error::success);
+
+  Result = FooSamples.addTotalSamples(Max);
+  ASSERT_EQ(Result, sampleprof_error::counter_overflow);
+  ASSERT_EQ(FooSamples.getTotalSamples(), Max);
+
+  Result = FooSamples.addHeadSamples(Max);
+  ASSERT_EQ(Result, sampleprof_error::counter_overflow);
+  ASSERT_EQ(FooSamples.getHeadSamples(), Max);
+
+  Result = FooSamples.addBodySamples(10, 0, Max);
+  ASSERT_EQ(Result, sampleprof_error::counter_overflow);
+  ErrorOr<uint64_t> BodySamples = FooSamples.findSamplesAt(10, 0);
+  ASSERT_FALSE(BodySamples.getError());
+  ASSERT_EQ(BodySamples.get(), Max);
+}
+
 } // end anonymous namespace