[PATCH] D62540: [SampleFDO] For functions without profiles, provide an option to put them in a special text section
Hal Finkel via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue May 28 12:17:38 PDT 2019
hfinkel added a comment.
I don't object to this functionality, but I wonder if this problem would be better solved in some other way. For example, why can't the sampling (post-)processing record the list of (MD5 hashes of) function names in the line table (or symbol table or whatever is relevant). If you have the list, then we don't need to guess whether a function missing from the profile is very cold or hadn't been added yet. I realize that this list might be large, but some kind of on-disk Bloom filter might work well (the Bloom filter will have some small possibility of false positives, but if rarely a cold function is treated as warm, that might be an acceptable tradeoff).
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