[PATCH] Fix: Relax nullptr C++11 rules in ms-mode

[Richard Smith]

LGTM. But please add a comment to AST/Expr.cpp near the
isCXX98IntegralConstantExpr check to say that we follow the C++98 rules in
Microsoft mode.


On Wed, Nov 6, 2013 at 5:31 AM, Will Wilson <will at indefiant.com> wrote:

> Thanks David! Patch attached...
>
>
> On 6 November 2013 14:25, David Majnemer <david.majnemer at gmail.com> wrote:
>
>> There doesn't seem to see a patch attached.
>>
>>
>> On Wed, Nov 6, 2013 at 2:50 AM, Will Wilson <will at indefiant.com> wrote:
>>
>>> Hi Richard,
>>>
>>> Only just had another crack at this MS mode issue. I've updated the
>>> patch and added your example to the test case. The new version correctly
>>> mirrors MSVC's handling in clang with C++11 mode active.
>>>
>>> All tests pass and clang-format applied. Let me know what you think.
>>>
>>> Cheers,
>>> Will.
>>>
>>>
>>> On 28 August 2013 03:11, Will Wilson <will at indefiant.com> wrote:
>>>
>>>> Thanks for the review (and catching the fail on my part)!
>>>>
>>>> MSVC accepts your templated example without complaint. The patched
>>>> clang asserts in EvalAddr() in SemaChecking.cpp after being called by
>>>> Sema::CheckReturnStackAddr() with "EvalAddr only works on pointers" using
>>>> your example case.
>>>>
>>>> Do you have some ideas on how best to support this facet of MSVC
>>>> behavior without uglifying the code too much?
>>>>
>>>> Thanks,
>>>> Will.
>>>>
>>>>
>>>> On 27 August 2013 22:04, Richard Smith <richard at metafoo.co.uk> wrote:
>>>>
>>>>> Please use isCXX98IntegralConstantExpr, not isIntegerConstantExpr, in
>>>>> C++11 + MicrosoftMode. (Take a look at how we behaved prior to r183883.) We
>>>>> *really* don't want to use full constexpr evaluation when determining
>>>>> whether an expression is a null pointer constant.
>>>>>
>>>>> Also, this patch tries to evaluate value-dependent potential null
>>>>> pointer constants in C++11 + MicrosoftMode. That's not OK, and will
>>>>> sometimes assert. How should we behave here? Does MSVC accept this:
>>>>>
>>>>> template<int N> int *f() { return N; }
>>>>> int *p = f<0>();
>>>>>
>>>>> ?
>>>>>
>>>>>
>>>>> On Tue, Aug 27, 2013 at 10:05 AM, Will Wilson <will at indefiant.com>wrote:
>>>>>
>>>>>> Hi All,
>>>>>>
>>>>>> This patch uses the more relaxed integer expression codepath in
>>>>>> Expr::isNullPointerConstant() when MicrosoftMode is enabled, this reflects
>>>>>> MSVC behavior and is required to compile various cases I've come across in
>>>>>> MSVC targeted code.
>>>>>>
>>>>>> Test case included. Built and tested against latest code. Please
>>>>>> review and commit if possible.
>>>>>>
>>>>>> Thanks!
>>>>>> Will.
>>>>>>
>>>>>> --
>>>>>> *Indefiant Ltd.*
>>>>>>
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>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> *Indefiant Ltd.*
>>>>
>>>
>>>
>>>
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>>> *Indefiant Ltd.*
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>
>
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> *Indefiant Ltd.*
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