tree 82ccb720f2ef3a59ce511f1467f48d983ac7255e
parent 304f3c294f9a673035f91c900586ef19e504265c
author Philip Reames <listmail@philipreames.com> 1638550360 -0800
committer Copybara-Service <copybara-worker@google.com> 1638551820 -0800

[funcattrs] Fix a bug in recently introduced writeonly argument inference

This fixes a bug in 740057d.  There's two ways to describe the issue:
* One caller hasn't yet proven nocapture on the argument.  Given that, the inference routine is responsible for bailing out on a potential capture.
* Even if we know the argument is nocapture, the access inference needs to traverse the exact set of users the capture tracking would (or exit conservatively).  Even if capture tracking can prove a store is non-capturing (e.g. to a local alloc which doesn't escape), we still need to track the copy of the pointer to see if it's later reloaded and accessed again.

Note that all the test changes except the newly added ones appear to be false negatives.  That is, cases where we could prove writeonly, but the current code isn't strong enough.  That's why I didn't spot this originally.

GitOrigin-RevId: 7b54de5feffedfc08e5a02d6c9e27c54e3b7f119