Thanks @rsmith; I don't have commit access, so can you land the updated patch for me?

Update test per review comments.

It looks like this went silent. I'm interested in atomic_ref as a downstream user; @BenjaminTrapani are you still interested in pushing this forward? If not I might be able to find someone to look into it...

It's about a year later; I'm curious if you've gained any insight into whether this is a good direction or not.

@philnik It looks like you're working on this in your spare time. Do you know when you'll be able to get back to it? Chromium downstream is waiting on this to land before updating to the latest libc++ sources, to avoid regressing perf.

In D113413#3512743, @ayzhao wrote:

We see that this patch is causing the size of the Chrome Android APK to increase by ~120 KB. This is confirmed via bisection. A breakdown of the symbols contributing to the size increase can be found at https://chrome-supersize.firebaseapp.com/viewer.html?load_url=https%3A%2F%2Fstorage.googleapis.com%2Fchromium-binary-size-trybot-results%2Fandroid-binary-size%2F2022%2F05%2F10%2F1112911%2Fsupersize_diff.sizediff&group_by=template .

At this point in time, I'm not exactly sure why this patch would increase the size by such a large amount. Does anyone have any ideas?

I don't have LLVM commit permissions; can you commit for me?

Review comments

Rebased, but now I got a strange AIX timeout. Presumably this is also flake or trunk bustage; PTAL?

Review comments

The MSAN failure doesn't look like me.

More formatting.

More bounds. Format.

Fix test failure.

MaskRay: Friendly ping.

Review comments.

This fixes a failing test.

In D118070#3297956, @thakis wrote:

I think the setup matches what we have in clang, right?

In D118070#3289222, @ychen wrote:

Thanks for doing this! Update the release note?

In D118070#3278123, @thakis wrote:

Things that can still improve:

1. This now does way more than just /winsysroot:. It also makes it so that lld-link works in a non-msvc shell by looking up libpaths in either registry or via setup api.

Refactored to share code with clang-cl. Still no tests.

Functional, but not yet refactored to share code with clang-cl.

Adds autodetection and full support for other clang-cl switches, but doesn't work: config->machine is not set this early, so it's always UNKNOWN.

Rebase