tree 8b4fc9b961090fcde29ce458447ed690f5b7092d
parent 35808ab8e18cea0a668ea91786a3d916618e986e
author Louis Dionne <ldionne@apple.com> 1593798401 -0400
committer Louis Dionne <ldionne@apple.com> 1593802689 -0400

[libc++/libc++abi] Automatically detect whether exceptions are enabled

Instead of detecting it automatically (in libc++) and relying on
_LIBCXXABI_NO_EXCEPTIONS being set explicitly (in libc++abi), always
detect whether exceptions are enabled automatically.

This commit also removes support for specifying -D_LIBCPP_NO_EXCEPTIONS
and -D_LIBCXXABI_NO_EXCEPTIONS explicitly -- those should just be inferred
from using -fno-exceptions (or an equivalent flag).

Allowing both -D_FOO_NO_EXCEPTIONS to be provided explicitly and trying
to detect it automatically is just confusing, especially since we did
specify it explicitly when building libc++abi. We should have only one
way to detect whether exceptions are enabled, but it should be robust.