[llvm-dev] LLVM and XCode 7.0.0

[Tim Northover via llvm-dev]

Hi Larry,

On 18 September 2015 at 00:02, Larry Gritz via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> First of all, can anybody say definitively which LLVM/Clang version corresponds to what Apple calls 7.0.0? Is there a web page somewhere with the list of correspondences?

I'm afraid there is no real correspondence. Xcode's clang & LLVM gets
branched at a fairly arbitrary point in time, and then many patches
are cherry-picked over time before it actually gets released.

That 3.6.0 just means that the initial branch happened some time
between the release of OSS 3.5 and OSS 3.6; it says nothing about what
bugs were fixed (or added!) before release, what features were ported
before release, or what features were implemented first in Xcode and
then made their way to OSS LLVM.

Because there's virtually no useful information to be gained from the
"based on LLVM ...", we've stopped reporting it in the version string.

> Or am I missing something obvious that I should be doing to detect versions more robustly?

Checking for the actual features you need is usually recommended. But
if that's not possible for some reason, you'll probably have to treat
Xcode Clang and OSS Clang as two different compilers.

Cheers.

Tim.