[PATCH] D119307: [Bitstream] Fix UB in left-shift in ReadVBR

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

Can you please rebase this on main and clarify which UB this addresses that is not covered by either https://github.com/llvm/llvm-project/commit/67348c8acfc205785996f2aea21b442f4b76f2c2 or https://github.com/llvm/llvm-project/commit/bf17cb294af422512b522575f3f74ab7964bf911? Please note that `-fsanitize=integer` includes a number of checks that are not actually undefined behavior. Some of the warnings quoted in the summary definitely cannot be fixed (e.g. DJB overflow is expected).

I believe a correct NumBits value is supposed to be a caller invariant (though this should probably be at least an assertion), which previously was not enforced in some cases due to an incorrect MaxChunkSize value.


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  https://reviews.llvm.org/D119307/new/

https://reviews.llvm.org/D119307