When -sample-profile-merge-inlinee is enabled, new FunctionSamples may be created during profile merge without GUIDToFuncNameMap being initialized. That will occasionally cause compiler crash. The patch fixes it.
It looks to me that we only need to transfer GUIDToFuncNameMap during merge as the map is shared, so it can be done at merge time like D84997. What do you think? That's the fixed we used internally.