[cfe-dev] [ubsan] Check recovery

[Will Dietz]

Forgive me, the previous patches erroneously aborted on a dynamic type
cache miss, updated patches attached.  Only the clang patch has
changed: added a parameter specifying this call should *always* be
recovered from.

Thanks!

On Fri, Nov 30, 2012 at 5:58 PM, Will Dietz <willdtz at gmail.com> wrote:
> Many of ubsan's checks are recoverable, and it'd be great to support
> doing so when possible.  Example use-case might be trying
> -fsanitize=undefined on a new code base that has many errors, where
> recovery would allow fixing them in bulk and require fewer
> build/test/fix cycles.
>
> This has been discussed a bit previously, and one of the biggest
> arguments against this was that making these paths recoverable might
> have a negative impact on performance.
>
> To help address this concern, attached are patches that add a
> -fsanitize-recover /cc1/ flag to enable performance tests with and
> without recovery enabled.  Suggestions on how to proceed with such
> testing would be appreciated :).
>
> If performance testing proves the difference is not a concern, the
> next step would be making recovery the default and
> -fsanitize-no-recover a driver-level flag (with no need for
> -fsanitize-recover).  It's certainly important to enable users to
> specify they want program execution halted on the first detected error
> as is presently the default.
>
> The "recover" phrasing is used (as opposed to "abort" of "trap"
> terminology) because many checks cannot be recovered from, so a flag
> like -fsanitize-no-abort would be misleading what it does.
>
> Review and feedback on this approach and its direction would be much
> appreciated.
>
> Thanks!
>
> ~Will
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