[llvm] [CAS] Add ObjectStore::getStandaloneMemoryBuffer() (PR #215360)

[Steven Wu via llvm-commits]

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@@ -371,6 +371,12 @@ class StandaloneDataInMemory {
   OnDiskGraphDB::FileBackedData
   getInternalFileBackedObjectData(StringRef RootPath) const;
 
+  /// Map this object's file independently of \a Region, so the result stays
+  /// valid after this object is gone. Returns \c nullptr if it cannot be done.
+  std::unique_ptr<MemoryBuffer>
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cachemeifyoucan wrote:

I thought the old version is not clear and rephrased it. It is returning nullptr. This is a private helper function that returns nullptr if the fast path cannot be taken. Caller is supposed to memcpy the buffer (together with a few other conditions). 

https://github.com/llvm/llvm-project/pull/215360