[llvm] [llvm-profdata] Emit warning when counter value is greater than 2^56. (PR #69513)

[Arthur Eubanks via llvm-commits]

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@@ -202,11 +202,13 @@ class InstrProfReader {
   /// instrprof file.
   static Expected<std::unique_ptr<InstrProfReader>>
   create(const Twine &Path, vfs::FileSystem &FS,
-         const InstrProfCorrelator *Correlator = nullptr);
+         const InstrProfCorrelator *Correlator = nullptr,
+         std::optional<std::function<void(Error)>> MaybeWarnFn = {});
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aeubanks wrote:

as nice as it is to explicitly state that this can be null, `std::function` can already be null and that's widely used in C++, so I'd just make this a `std::function<>` and use its bool conversion to check if it has a value

https://github.com/llvm/llvm-project/pull/69513