commit 5765bb80a9cb405f994291d635d5afa7b4db5439
author Lukasz Anforowicz <lukasza@google.com> Tue May 17 17:21:06 2022 -0700
committer Copybara-Service <copybara-worker@google.com> Tue May 17 17:21:30 2022 -0700
tree 4eaf1c4a0aa58cdd0812d6ecaa4d7e8de40c998a
parent 57aac9389b3d0ff31bd089c4da3f2ec6a7b41c30

Fix offset of fields represented as opaque blobs of bytes.

Crubit represents some C++ fields as opaque blobs of bytes in the
generated Rust structs.  Today this happens for `[[no_unique_address]]`
fields.  In the future, this may also happen for fields of an otherwise
unsupported C++ type.

The opaque blobs of bytes intentionally have no alignment (to precisely
control their size).  Unfortunately, the offset of such fields may
depend on the alignment - the tests added by this CL illustrate the
scenarios where the offset of the generated Rust field might not match
the offset of the original C++ field.

This CL inserts an additional `__padding<N>` field as needed to fix the
offset of fields represented as opaque blobs of bytes.

PiperOrigin-RevId: 449354029