[llvm] [BOLT][merge-fdata]Fix support for fdata files starting with no_lbr on ARM platform (PR #112328)

[Amir Ayupov via llvm-commits]

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@@ -265,7 +252,10 @@ bool isYAML(const StringRef Filename) {
 void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
   errs() << "Using legacy profile format.\n";
   std::optional<bool> BoltedCollection;
+  std::optional<bool> NoLbr;
   std::mutex BoltedCollectionMutex;
+  std::mutex NoLbrMutex;
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aaupov wrote:

Can we avoid the use of mutexes here by just setting bolted_collection/no_lbr per profile and checking that after we parse all profiles?

https://github.com/llvm/llvm-project/pull/112328