[llvm] r185024 - ARM: Proactively ensure that the LowerCallResult hack for 'this'-returns is not used for incompatible calling conventions.

[Stephen Lin]

> Is it actually returning NULL in these cases or should it? Also the
> comment looks weird underneath the line :)

It should in the future, in case the situation arises...(I am just
being proactive to reduce the chance of something silently adding a
calling convention that causes this to break in the future...)

I will make this clearer.

>
>
>> +  // getThisReturnPreservedMask - Returns a call preserved mask specific to the
>> +  // case that 'returned' is  an i32 first argument if the calling convention
>> +  // is one that can (partially) model this attribute with a preserved mask
>> +  // (i.e. it is a calling convention that uses the same register for the first
>> +  // i32 argument and an i32 return value)
>> +  //
>> +  // Should return NULL in the case that the calling convention does not have
>> +  // this property
>> +  const uint32_t *getThisReturnPreservedMask(CallingConv::ID) const;
>> +
>
> Doxygen style comments would be good here matching the ones above.

Hmm, do I just need to change "//" to "///"? I have not actually
learned the rules -- I've just mimicked what I've seen and assumed
doxygen would figure it out :)

Stephen