tree fe1fe9f081d1bca253fbc22c8ecf12deb7eecc42
parent 633b45efbeeb3df6bac7e3caec5eca468ffbce97
author James Y Knight <jyknight@google.com> 1607354809 -0500
committer Copybara-Service <copybara-worker@google.com> 1611866131 -0800

Itanium Mangling: Mangle `__alignof__` differently than `alignof`.

The two operations have acted differently since Clang 8, but were
unfortunately mangled the same. The new mangling uses new "vendor
extended expression" syntax proposed in
https://github.com/itanium-cxx-abi/cxx-abi/issues/112

GCC had the same mangling problem, https://gcc.gnu.org/PR88115, and
will hopefully be switching to the same mangling as implemented here.

Additionally, fix the mangling of `__uuidof` to use the new extension
syntax, instead of its previous nonstandard special-case.

Adjusts the demangler accordingly.

Differential Revision: https://reviews.llvm.org/D93922

GitOrigin-RevId: 9c7aeaebb3ac1b94200b59b111742cb6b8f090c2