[llvm] [SampleFDO][NFC] Refactoring sample reader to support on-demand read profiles for given functions (PR #104654)

[via llvm-commits]

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@@ -791,6 +798,19 @@ bool SampleProfileReaderExtBinaryBase::useFuncOffsetList() const {
   return false;
 }
 
+std::error_code
+SampleProfileReaderExtBinaryBase::read(const DenseSet<StringRef> &FuncsToUse,
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WenleiHe wrote:

Now we need to check whether a profile is already loaded, before attempt to load. 

https://github.com/llvm/llvm-project/pull/104654