[cfe-commits] r154248 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td include/clang/Sema/Sema.h lib/Sema/SemaAccess.cpp lib/Sema/SemaDeclCXX.cpp lib/Sema/SemaExprCXX.cpp lib/Sema/SemaInit.cpp test/CXX/class.access/class.protected/p1.c

[John McCall]

On Apr 10, 2012, at 7:36 AM, Francois Pichet wrote:
> On Mon, Apr 9, 2012 at 1:34 PM, John McCall <rjmccall at apple.com> wrote:
>> On Apr 8, 2012, at 2:29 AM, Francois Pichet wrote:
>>> On Fri, Apr 6, 2012 at 11:04 PM, John McCall <rjmccall at apple.com> wrote:
>>>> Author: rjmccall
>>>> Date: Fri Apr  6 22:04:20 2012
>>>> New Revision: 154248
>>>> 
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=154248&view=rev
>>>> Log:
>>>> Fix several problems with protected access control:
>>>>  - The [class.protected] restriction is non-trivial for any instance
>>>>    member, even if the access lacks an object (for example, if it's
>>>>    a pointer-to-member constant).  In this case, it is equivalent to
>>>>    requiring the naming class to equal the context class.
>>>>  - The [class.protected] restriction applies to accesses to constructors
>>>>    and destructors.  A protected constructor or destructor can only be
>>>>    used to create or destroy a base subobject, as a direct result.
>>>>  - Several places were dropping or misapplying object information.
>>>> 
>>>> The standard could really be much clearer about what the object type is
>>>> supposed to be in some of these accesses.  Usually it's easy enough to
>>>> find a reasonable answer, but still, the standard makes a very confident
>>>> statement about accesses to instance members only being possible in
>>>> either pointer-to-member literals or member access expressions, which
>>>> just completely ignores concepts like constructor and destructor
>>>> calls, using declarations, unevaluated field references, etc.
>>>> 
>>> 
>>> Hi John,
>>> I am not asking you to make the modification but do you have any
>>> suggestion about how to handle case like that in MicrosoftMode?
>>> 
>>> class A {
>>> protected:
>>>       void f();
>>> };
>>> 
>>> class B : public A{
>>> public:
>>>       void test();
>>> };
>>> 
>>> void B::test() {
>>>       &A::f;
>>> }
>> 
>> 
>> It should be trivial to disable the additional restrictions in MicrosoftMode.
>> Does MSVC implement the protected member access restriction at all,
>> or does it just miss it in the case of pointer-to-members?
>> 
>> Try this:
>> 
>>  void B::test() {
>>   A *a = 0;
>>   a->f();
>>  }
> 
> MSVC will give an error for this case.
> So MSVC just seem to miss the pointer-to-members case and this cause a
> regression with MFC code.

Okay.  Then I think the right thing to do is to just add something like
  if (S.getLangOpts().MicrosoftMode) return AR_accessible;
with the appropriate comment somewhere around SemaAccess.cpp:782.
Would you mind fleshing out a patch and testcases for that?

John.