r264428 - [ASTMatchers] Fix build for VariadicFunction.

[David Blaikie via cfe-commits]

Yep, reproduces even with a plain (non template arg) function pointer - and
immediately goes away with a real function of the same type.

That's bothersome. I played around with a few ways of writing the
call-to-function-pointer but couldn't find any particular syntax that
seemed to untickle GCC's problem here. Maybe if you find the filed GCC bug
there might be a workaround listed (if it's been filed/investigated
already).

On Thu, Mar 31, 2016 at 6:53 AM, Samuel Benzaquen <sbenza at google.com> wrote:

> I was able to reduce the bug to this:
>
> struct A {
>
>   A(int (&)[1]);
>
> };
>
> template <int (*F)(A)>
>
> int E() {
>
>   int X[] = {0};
>
>   return F(X);
>
> }
>
>
> Note that the array is not empty and we are not using variadics anymore.
> The problem seems to be related to the function pointer template parameter.
> gcc doesn't want to do the implicit conversion from X to A, but if I make
> the conversion explicit it works.
>
>
> On Fri, Mar 25, 2016 at 1:58 PM, Alexey Samsonov <vonosmas at gmail.com>
> wrote:
>
>>
>> On Fri, Mar 25, 2016 at 10:55 AM, David Blaikie via cfe-commits <
>> cfe-commits at lists.llvm.org> wrote:
>>
>>>
>>>
>>> On Fri, Mar 25, 2016 at 10:46 AM, Samuel Benzaquen via cfe-commits <
>>> cfe-commits at lists.llvm.org> wrote:
>>>
>>>> Author: sbenza
>>>> Date: Fri Mar 25 12:46:02 2016
>>>> New Revision: 264428
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=264428&view=rev
>>>> Log:
>>>> [ASTMatchers] Fix build for VariadicFunction.
>>>>
>>>> Under some conditions the implicit conversion from array to ArrayRef<>
>>>> is not working.
>>>>
>>>
>>> Any idea what those conditions are?
>>>
>>
>> This was causing the build failure with opt GCC. I will try to create a
>> smaller reproducer later today.
>>
>>
>>>
>>>
>>>> Fix the build by making it explicit.
>>>>
>>>> Modified:
>>>>     cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h
>>>>
>>>> Modified: cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h?rev=264428&r1=264427&r2=264428&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h (original)
>>>> +++ cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h Fri Mar
>>>> 25 12:46:02 2016
>>>> @@ -90,7 +90,7 @@ private:
>>>>    // before we make the array.
>>>>    template <typename... ArgsT> ResultT Execute(const ArgsT &... Args)
>>>> const {
>>>>      const ArgT *const ArgsArray[] = {&Args...};
>>>> -    return Func(ArgsArray);
>>>> +    return Func(ArrayRef<const ArgT *>(ArgsArray, sizeof...(ArgsT)));
>>>>    }
>>>>  };
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> cfe-commits mailing list
>>>> cfe-commits at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>>>>
>>>
>>>
>>> _______________________________________________
>>> cfe-commits mailing list
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>>>
>>>
>>
>>
>> --
>> Alexey Samsonov
>> vonosmas at gmail.com
>>
>
>
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