[PATCH] D38209: [Sema] Correct nothrow inherited by noexcept

Aaron Ballman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Mon Sep 25 13:42:42 PDT 2017

aaron.ballman added a reviewer: rsmith.
aaron.ballman added a comment.

In https://reviews.llvm.org/D38209#880553, @STL_MSFT wrote:

> > do you think `__declspec(nothrow)` calling the terminate handler in Clang is a bug?
> It's certainly a behavior difference with potential performance impact, although I don't think it can be viewed as a bug, strictly speaking. MSVC treats `__declspec(nothrow)` as an optimization request, with undefined behavior if it's violated. Termination is definitely one of the possible results of undefined behavior.
> We've recently had to slightly rethink our EH strategy in light of C++17's addition of noexcept into the type system, and the removal of dynamic exception specifications (and the change in semantics to throw()). MSVC's /EHsc makes this extra fun. If you're interested, I can put you in contact with the compiler dev who recently made those changes.

That might be helpful. I'm mostly interested in whether `__declspec(nothrow)` is intended to be part of the type system in the same way `noexcept` specifiers are.

@erichkeane -- can you see whether `__attribute__((nothrow))` is part of the type system as far as GCC is concerned (in C++17 mode, assuming GCC has implemented that functionality already)?


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