[libc++abi] Implement __cxa_init_primary_exception and use it to optimize std::make_exception_ptr (#65534)
This patch implements __cxa_init_primary_exception, an extension to the
Itanium C++ ABI. This extension is already present in both libsupc++ and
libcxxrt. This patch also starts making use of this function in
std::make_exception_ptr: instead of going through a full throw/catch
cycle, we are now able to initialize an exception directly, thus making
std::make_exception_ptr around 30x faster.
GitOrigin-RevId: 51e91b64d0deb6a743861c2a0fba84865250036e
3 files changed
