This PR fixes the bug in alpha.webkit.NoDeleteChecker that it emits a
warning for any function without
[[clang::annotate_type("webkit.nodelete")]] annotation if it contains
non-trivial code. It also fixes a bug hat we weren't checking the
presence of the annotation on superclass' corresponding member
functions.
This PR adds the support for specifying
`[[clang::annotate_type("webkit.nodelete")]]` on a function return type,
in which case, the whole function is considered "trivial" or more
precisely that it does not trigger any destruction of an object.
This PR also introduces alpha.webkit.NoDeleteChecker which validates
soundness of the annotation by examining the function body. The checker
will warn if `[[clang::annotate_type("webkit.nodelete")]]` is specified
on a function with a body which does not pass the triviality test.
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Co-authored-by: Balazs Benics <benicsbalazs@gmail.com>
