[PATCH] D32927: [libc++] Implement exception_ptr on Windows

[Eric Fiselier via Phabricator via cfe-commits]

EricWF added a comment.

In https://reviews.llvm.org/D32927#748119, @bcraig wrote:

> libstdc++ and the Visual Studio C++ runtime have very different compatibility expectations.


I only meant to imply that linking to another standard library implementation hasn't caused major issues
in the past.

> Is there a particular reason to go with a shorter term solution now, rather than straight to the long term solution?  Is there a deadline or a particular milestone we are trying to hit for clang-cl support?  Or is there a suspicion that future changes will make a really good implementation possible, incentivizing us to do something inexpensive for now?

My main desire is to get the test suite green so we can start detecting regressions. This patch reduces the remaining test failures by half, and although not future proof, it is correct at the moment.
Plus I would really prefer writing the more complex implementation against a set of tests that are already passing.

I also think this patch is a step in the right direction, regardless of the final implementation. The bulk of this patch is just boilerplate, setting up the correct declarations and definitions for implementing `exception_ptr` targeting Microsoft's ABI as opposed to Itanium.
It would be nice to commit these changes apart from the future implementation, and this seems like an OK way to do that.

@bcraig Since this patch doesn't preclude improvements in the future are you OK to move forward with it? I agree this shouldn't be `exception_ptr`'s final form, and I plan to continue working on the suggested implementation, but I don't want to block other Windows
progress while this is ongoing (and that's what having an un-implemented exception_ptr is doing).


https://reviews.llvm.org/D32927