GitLab

Rework the seccomp_bpf compiler internals to work in terms of a single
general masked-equality condition instead of the variety of limited
condition operators previously supported.  All of the peephole
optimizations previously applied continue to be supported so similar
instructions should be emitted, but the handling of upper/lower words
is more cleanly structured now.

The old sandbox->Cond() interface continues to be supported for now so
that the old seccomp_bpf_unittests continue to give us assurances that
the new code generator is still correct.  Meanwhile, we provide a new
lower-level sandbox->CondMaskedEqual() method that bpf_dsl can now use.

BUG=408845
R=jln@chromium.org

Review URL: https://codereview.chromium.org/530133003

Cr-Commit-Position: refs/heads/master@{#293347}