[webkit-dev] Proposal: Dropping MSVC support and use clang-cl exclusively on Windows

[Olmstead, Don]

Hi Herb

If you grep around the WebKit codebase for COMPILER(MSVC) there are a number of workarounds hanging out. Some may have been fixed over time but the workaround wasn’t removed.

Biggest issue was around the JIT and some other low level features the JSC folks utilize that isn’t present in MSVC. The lion’s share of JSC development is done using Clang and those working on it don’t have a Windows box handy so we have seen the JIT break on Windows. Yusuke I’m sure has a list of feature requests that would improve the quality of MSVC for people developing VMs.

MSVC has definitely caught some issues in the code and compiler mono-culture isn’t great but realistically we don’t have the resources to keep MSVC up and running.

Regards,
Don

From: Jean-Yves Avenard via webkit-dev <webkit-dev at lists.webkit.org>
Sent: Wednesday, May 1, 2024 5:10 PM
To: Herb Sutter <herb.sutter at gmail.com>
Cc: Webkit Development List <webkit-dev at lists.webkit.org>
Subject: Re: [webkit-dev] Proposal: Dropping MSVC support and use clang-cl exclusively on Windows

Hi


On 2 May 2024, at 10:07 am, Herb Sutter via webkit-dev <webkit-dev at lists.webkit.org<mailto:webkit-dev at lists.webkit.org>> wrote:


We’ve had full C++20 including concepts for a couple of years so I wasn’t sure what problem you were running into… are you encountering bugs in those features? or you can’t turn on /std:c++20 for some reason? or are you using an older pre-concepts (pre-VS2022 17.0) compiler?

Thanks for any feedback you have time to share.

Herb


We’ve had issues where some use of concepts made the latest MSVC compiler crash
See https://searchfox.org/wubkat/source/Source/WTF/wtf/TypeTraits.h#145-172<https://searchfox.org/wubkat/source/Source/WTF/wtf/TypeTraits.h#145-172>

See https://bugs.webkit.org/show_bug.cgi?id=261598<https://bugs.webkit.org/show_bug.cgi?id=261598>

Jean-Yves
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