[PATCH] Add llvm::make_unique, according to N3656.

[Ahmed Charles]

================
Comment at: include/llvm/ADT/STLExtras.h:274
@@ +273,3 @@
+template <class T>
+typename std::enable_if<std::is_array<T>::value &&std::extent<T>::value == 0,
+                        std::unique_ptr<T>>::type
----------------
Chandler Carruth wrote:
> this && seems like it needs a space on the RHS... Maybe a clang-format bug?
yes, clang format thinks it's an rvalue reference, apparently.

================
Comment at: include/llvm/ADT/STLExtras.h:281
@@ +280,3 @@
+template <class T, class... Args>
+typename std::enable_if<std::extent<T>::value != 0>::type
+make_unique(Args &&...) LLVM_DELETED_FUNCTION;
----------------
Chandler Carruth wrote:
> Do you not need the is_array test here?
extent returns 0 for non-arrays and unbound arrays.

================
Comment at: unittests/ADT/MakeUniqueTest.cpp:17-18
@@ +16,4 @@
+
+// Test fixture
+class MakeUniqueTest : public testing::Test {};
+
----------------
Chandler Carruth wrote:
> No need for an empty fixture. Just remove the _F suffix below.
Sure

================
Comment at: include/llvm/ADT/STLExtras.h:266
@@ +265,3 @@
+
+/// Implement make_unique according to N3656.
+template <class T, class... Args>
----------------
Chandler Carruth wrote:
> I think it would be good to give a reasonable full description of how to use both this and the array form. You should cite the paper its based on, but not require a caller to read it.
Done.


http://llvm-reviews.chandlerc.com/D3013