[cfe-commits] Fix PR13434 - mangling of templates with function pointers as arguments

[Timur Iskhodzhanov]

I've started with a small r160783 that ...

On Mon, Jul 23, 2012 at 9:37 PM, John McCall <rjmccall at apple.com> wrote:
> On Jul 23, 2012, at 4:52 AM, Timur Iskhodzhanov wrote:
>> 2) See the zeta mangling in mangle-ms.cpp - not sure if changing the
>> mangling there is a problem at all, as "blocks" are never
>> compiled/mangled by MSVS (they are clang-specific extensions).
>
> It would be good to at least come up with a reasonable-seeming
> mangling for them.  Basically, please make sure they're mangled
> just like pointers to functions, but different in some obvious way.
... adds an zeta/eta comparison between function pointer and block mangling ...

On Tue, Jul 24, 2012 at 12:53 AM, Charles Davis <cdavis at mymail.mines.edu> wrote:
>
> On Jul 23, 2012, at 5:52 AM, Timur Iskhodzhanov wrote:
>
>> Hi Charles, John,
>>
>> Can you please see
>> http://llvm.org/bugs/show_bug.cgi?id=13434
>> ?
>> It seems like this case has never been tested before.
>>
>> I've written some tests and made a simple fix to the code.
>>
>> It's not thoroughly tested on all cases but IMO adding at least some
>> new coverage and making all new tests pass by a simple is a good
>> progress to start with.
>>
>> Two questions:
>> 1) See the FIXME comment in MicrosoftMangle - I do think the whole
>> comment should be made less cryptic.
>>  Probably I'll need some help from Charles to decipher this :)
> I already acted on that suggestion. You can safely remove the 'I'll probably have…' part.
... and removes the "I'll probably have" part.

>> 2) See the zeta mangling in mangle-ms.cpp - not sure if changing the
>> mangling there is a problem at all, as "blocks" are never
>> compiled/mangled by MSVS (they are clang-specific extensions).
> OK, but what about lambdas?
The lambdas are just not supported in MicrosoftMangle (compared to
ItaniumMangle) so I don't think mangling of templates with lambda
parameters is a priority now? :)

> Oh, and, as John said, the mangling of a block pointer should resemble that of a function pointer (i.e. no '$$A6').
Yeah, I think so too now. Trying to achieve that...

>> Can you please review the patch?
> Seems to me that the '$$A' part is specific to template parameters that are neither pointers nor references to functions. What happens in those cases? The '6' is probably because this is a global (near) function. What happens when the NTTP is a member function? (Can you even do that?)
Oh my god!

----------------------------------
template<typename T> class Z {};

class C {
 public:
  void method() {}
};

template<typename T> class Z<void (T::*)(void)> {};
void foo(Z<void (C::*)(void)>) {}
// CHECK: "\01?foo@@YAXV?$Z at P8C@@AEXXZ@@@Z"
----------------------------------

> Chip
>