1080968 - Add support for constexpr and explicit conversions on clang-cl

Status: RESOLVED FIXED

(Core :: MFBT, defect)

Comment 1

[(no longer active)]

Attachment: Add support for constexpr and explicit conversions on clang-cl

Comment 2

[Nathan Froyd [:froydnj]]

Comment on attachment 8502950 [details] [diff] [review]
Add support for constexpr and explicit conversions on clang-cl

Review of attachment 8502950 [details] [diff] [review]:
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I guess clang-cl doesn't support the __attribute__ syntax for things, so we can't be clever here and just do something like:

#if defined(_MSC_VER) && !defined(__clang__) // native MSVC
...
#elif defined(__clang__) // clang or clang-cl on Windows
...
#elif defined(__GNUC__) // gcc
...
#endif

?  I guess that would shut out doing things with clang-cl's MSVC version emulation...

Comment 3

[(no longer active)]

I think it actually does support __attribute__, but I'd prefer to keep as much as of the logic shared with MSVC (since it's supposed to be a drop-in replacement and all.)

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/d27ce1e75719

Comment 5

[(no longer active)]

In hindsight, the constexpr part of this was a stupid idea.  constexpr-ness of things can change ABI requirements, and I keep running into ABI miscompat issues when some object files are compiled with cl and some with clang-cl where the problem boils down to clang-cl choosing constexpr and MSVC 2013 not, and I'm tired of this!

I'm going to revert the constexpr part of this bug.  Sorry for being silly!

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/4cc67dcae188

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/4cc67dcae188

Comment 8

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/4cc67dcae188