[PATCH] D32435: clang-cl: Add support for /permissive-

[Nico Weber via cfe-commits]

"Opting into the conforming mode, /permissive-, during the series of VS
2017 update is a commitment to keeping your code base clean and to fixing
non-conforming constructs we fix conformance issues in Visual C++." [...]
"By contrast /permissive- offers a useful conformance mode where input C++
code is interpreted according to ISO C++ rules but also allows conforming
extensions necessary to compile C++ on targets supported by Visual C++."

I guess the second quote agrees with your interpretation.

We already diag most of the things they already mention. The one thing we
don't diag by default is Wmicrosoft-enum-forward-reference since that's
only an Extension and not an ExtWarn. We don't expose -pedantic from
clang-cl, so this seemed like a somewhat natural mapping to me.

Should /permissive- map to -Wmicrosoft instead and turn on the parts of
-Wmicrosoft that are Extensions? Should we just ignore /permissive- and
possibly make some of our -Wmicrosoft Extensions ExtWarns instead?

On Mon, Apr 24, 2017 at 2:10 PM, David Majnemer <david.majnemer at gmail.com>
wrote:

> -pedantic means "Issue all the warnings demanded by strict ISO C and ISO
> C++; reject all programs that use forbidden extensions, and some other
> programs that do not follow ISO C and ISO C++."
> I believe it is more akin to -fno-ms-compatibility as it disables
> compatibility hacks.
>
> On Mon, Apr 24, 2017 at 11:02 AM, Nico Weber <thakis at chromium.org> wrote:
>
>> It does sound pretty similar to me from the blog post. I think this is a
>> decent place to start from.
>>
>> On Apr 24, 2017 11:55 AM, "David Majnemer via Phabricator via
>> cfe-commits" <cfe-commits at lists.llvm.org> wrote:
>>
>>> majnemer requested changes to this revision.
>>> majnemer added a comment.
>>> This revision now requires changes to proceed.
>>>
>>> I don't think this is correct. GDR (of Microsoft) says the behavior is
>>> different: https://www.reddit.com/r/cpp/comments/5dh7j5/visual_c_introd
>>> uces_permissive_for_conformance/da5fxjj/
>>>
>>>
>>> https://reviews.llvm.org/D32435
>>>
>>>
>>>
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>>> cfe-commits mailing list
>>> cfe-commits at lists.llvm.org
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>>
>
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