std exception throws

(Note that we assume a table-based EH implementation here, a SJLJ EH implementaton would have even happy and sad path runtime overhead. Table-based EH implementations are almost universal on x64, ARM and AArch64 targets).

C++ exception throws came in the original C++ 98 standard – at that time, not all the major compilers implemented them yet, and several of those who did did not have efficient implementations, plus in the original days some compiler vendors still patented things like EH implementation techniques to try and maintain a competitive advantage over rival compilers. Unlike other C++ features, enabling C++ exceptions on a code base not written with them in mind is not safe, so this led to the C++ ecosystem becoming bifurcated into exceptions-enabled and exceptions-disabled camps.