[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, 2 insertions, 0 deletions

diff --git a/llvm/lib/ProfileData/SampleProf.cpp b/llvm/lib/ProfileData/SampleProf.cpp
index 1b76367f4de..9ded757f2b2 100644
--- a/llvm/lib/ProfileData/SampleProf.cpp
+++ b/llvm/lib/ProfileData/SampleProf.cpp
@@ -45,6 +45,8 @@ class SampleProfErrorCategoryType : public std::error_category {
       return "Truncated function name table";
     case sampleprof_error::not_implemented:
       return "Unimplemented feature";
+    case sampleprof_error::counter_overflow:
+      return "Counter overflow";
     }
     llvm_unreachable("A value of sampleprof_error has no message.");
   }