[PATCH] D95534: clang-cl: Invent a /winsysroot concept

[Alexandre Ganea via Phabricator via cfe-commits]

aganea added a comment.

In D95534#2550998 <https://reviews.llvm.org/D95534#2550998>, @thakis wrote:

> In D95534#2534510 <https://reviews.llvm.org/D95534#2534510>, @smeenai wrote:
>
>> I saw this on LLVM Weekly, and I like it a lot :)
>>
>> Now if only Windows could case-correct their SDKs so we didn't need VFS overlays and symlinks for the linker...
>
> We use ciopfs for this, https://source.chromium.org/chromium/chromium/src/+/master:build/vs_toolchain.py;l=485?q=ciopfs That code has worked without changes for the last 2.5 years.

//(sorry a bit off topic for LLVM)//
Hello @thakis ! What is the best way to report Chrome dev issues? I wanted to try ciopfs, so I followed the guide here <https://chromium.googlesource.com/chromium/src/+/master/docs/win_cross.md>, but clang-cl then fails with "Too many files open", pointing to files in `chromium/src/third_party/depot_tools/win_toolchain/vs_files/`. I've removed the ciopfs mount point and instead created a 'casefold' folder at the same location (ie. `chattr +F vs_files`), unzipped the SDKs again, and now the build compiles fine. Raising `ulimit -n 250000` and `fs.file-max = 1000000` didn't help the ciopfs issue in the first place. I'm running on a 48C/96T machine on Ubuntu 20.04. There seems to be either a leak of FDs or caching inside ciopfs? Any suggestions?


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