[llvm] r208388 - Remove use of = default/= delete as they're unsupported on MSVC2012

[David Blaikie]

Oh, and if we get really bad about this and /keep/ using = default and
having to fix it... we could introduce a warning in Clang to catch
this, maybe. But I wouldn't go there just yet.

On Thu, May 8, 2014 at 8:11 PM, David Blaikie <dblaikie at gmail.com> wrote:
> On Thu, May 8, 2014 at 8:06 PM, NAKAMURA Takumi <geek4civic at gmail.com> wrote:
>> Thanks, David. I wondered how to introduce alternative of defaulted
>> functions on that.
>>
>> We can add LLVM_DELETED_FUNCTION with "= delete". It'd be better to
>> put deleted functions into private scope for deleted-unaware
>> compilers, though.
>
> The privacy isn't /too/ much of an issue. Yeah, it'd help people
> developing on MSVC2012 to not break things (since they'd get a
> compilation error instead of a linker error) but between buildbot
> coverage and lots of developers using things that do support = delete,
> it wouldn't be too much of a burden to fix/revert if/when the odd
> MSVC2012-using developer introduced a call to them.
>
> The short answer is, I think: don't bother. Just write out the special
> members (don't use = default, do use = delete via
> LLVM_DELETED_FUNCTION) until we drop MSVC2012 compatibility.
>
>> Jordan, I wonder how to implement defaulted functions with macros...
>>
>> 1. Conditionalize
>>
>> #if LLVM_DEFAULTED_FUNCTION_AVAILABLE
>>   MoveOnly(...) = default;
>> #endif
>>
>> 2. Conditionalize with macro
>>
>> #define LLVM_DEFAULTED_FUNCTION(decl) decl = default /* or eliminate entirely */
>>
>>   LLVM_DEFAULTED_FUNCTION(MoveOnly(...));
>
> This works only for those functions that don't actually require an
> implementation... which is basically the default ctor and the dtor.
> Not move/copy operations (which, if not defaulted, would need the
> members to be enumerated to copy/move them)
>
>>
>> 3. Give the body to each functionality.
>>
>> #if !__has_feature(cxx_defaulted_functions)
>> #  define LLVM_DEFAULTED_EMPTY_CONSTRUCTOR {}
>> #  define LLVM_DEFAULTED_COPY_FUNCTION(arg) {*this = arg;}
>> #endif
>>
>> 0. Ask C++ guru!
>>
>> 2014-05-09 11:26 GMT+09:00 David Blaikie <dblaikie at gmail.com>:
>>> Author: dblaikie
>>> Date: Thu May  8 21:26:36 2014
>>> New Revision: 208388
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=208388&view=rev
>>> Log:
>>> Remove use of = default/= delete as they're unsupported on MSVC2012
>>>
>>> Modified:
>>>     llvm/trunk/unittests/ADT/StringMapTest.cpp
>>>
>>> Modified: llvm/trunk/unittests/ADT/StringMapTest.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/StringMapTest.cpp?rev=208388&r1=208387&r2=208388&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/unittests/ADT/StringMapTest.cpp (original)
>>> +++ llvm/trunk/unittests/ADT/StringMapTest.cpp Thu May  8 21:26:36 2014
>>> @@ -221,10 +221,15 @@ TEST_F(StringMapTest, NonDefaultConstruc
>>>  struct MoveOnly {
>>>    int i;
>>>    MoveOnly(int i) : i(i) {}
>>> -  MoveOnly(MoveOnly &&) = default;
>>> -  MoveOnly(const MoveOnly &) = delete;
>>> -  MoveOnly &operator=(MoveOnly &&) = default;
>>> -  MoveOnly &operator=(const MoveOnly &) = delete;
>>> +  MoveOnly(MoveOnly &&RHS) : i(RHS.i) {}
>>> +  MoveOnly &operator=(MoveOnly &&RHS) {
>>> +    i = RHS.i;
>>> +    return *this;
>>> +  }
>>> +
>>> +private:
>>> +  MoveOnly(const MoveOnly &);
>>> +  MoveOnly &operator=(const MoveOnly &);
>>>  };
>>>
>>>  TEST_F(StringMapTest, MoveOnlyKey) {
>>>
>>>
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