[webkit-dev] Build slave for JSCOnly Linux MIPS

Konstantin Tokarev annulen at yandex.ru
Tue Apr 19 12:46:50 PDT 2016

19.04.2016, 22:22, "Anders Carlsson" <andersca at apple.com>:
>> On Apr 19, 2016, at 12:21 PM, Konstantin Tokarev <annulen at yandex.ru> wrote:
>> 19.04.2016, 22:11, "Anders Carlsson" <andersca at apple.com>:
>>>>  On Apr 19, 2016, at 12:09 PM, Konstantin Tokarev <annulen at yandex.ru> wrote:
>>>>  19.04.2016, 21:38, "Anders Carlsson" <andersca at apple.com>:
>>>>>  I’d like us to switch over to using C++14 in WebKit2 so we can get the new generalized lambda capture (https://isocpp.org/files/papers/N3648.html), so we can capture move-only types in lambdas. According to https://gcc.gnu.org/projects/cxx-status.html that would require GCC 4.9.
>>>>  This code compiles fine with GCC 4.8 with -std=c++1y flag:
>>>>  auto f(std::unique_ptr<int> ptr)
>>>>  {
>>>>     [value = std::move(ptr)] {return *value;};
>>>>  }
>>> GCC 4.8 has “partial” support, which may or may not be OK for our purposes. I’d rather be safe than sorry.
>> From https://gcc.gnu.org/gcc-4.9/changes.html#cxx:
>> "
>> G++ supports C++1y lambda capture initializers:
>>    [x = 42]{ ... };
>> Actually, they have been accepted since GCC 4.5, but now the compiler doesn't warn about them with -std=c++1y, and supports parenthesized and brace-enclosed initializers as well.
>> "
>> So it states pretty clearly what is supported only since 4.9
> According do  https://gcc.gnu.org/projects/cxx-status.html (which I linked in original e-mail), GCC 4.5 has “partial” support.

...and quote from release notes above explains that "partial" means "without 
parenthesized and brace-enclosed initializers".

Also, you cannot be safe with GCC anyway, it often has bugs in newly introduced features which are discovered only after you write sufficiently sofisticated code using this feature.

However, this is fine with me if you start using C++14 constructions incompatible with GCC 4.8 in WebKit2. I was asking only about allowing GCC 4.8 for WTF and JSC.


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