[libcxx] [test] In test/support/test_allocator.h, fix construct() to avoid moving immovable types.
Summary:
In test/support/test_allocator.h, fix construct() to avoid moving immovable types.
This improves the allocator's conformance, and fixes compiler errors with MSVC's STL. The scenario is when the allocator is asked to construct an object of type X that's immovable (deleted copy/move ctors), but implicitly constructible from an argument type A. When perfectly forwarded, X can be (explicitly) constructed from A, and everything is fine. That's std::allocator's behavior, and the Standard's default when a user allocator's construct() doesn't exist. The previous implementation of construct() here mishandled this scenario. Passing A to this construct() would implicitly construct an X temporary, bound to (non-templated) T&&. Then construct() would attempt to move-construct X from that X temporary, but X is immovable, boom.
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D21094
llvm-svn: 272747
GitOrigin-RevId: 4fae50267adb027583315842b169a8f6af7e06da
diff --git a/test/support/test_allocator.h b/test/support/test_allocator.h
index ce61f38..b96e6c5 100644
--- a/test/support/test_allocator.h
+++ b/test/support/test_allocator.h
@@ -80,14 +80,14 @@
{assert(data_ >= 0); --alloc_count; ::operator delete((void*)p);}
size_type max_size() const throw()
{return UINT_MAX / sizeof(T);}
+#if TEST_STD_VER < 11
void construct(pointer p, const T& val)
- {::new(p) T(val);}
-#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
- void construct(pointer p, T&& val)
- {::new(p) T(std::move(val));}
-#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+ {::new(static_cast<void*>(p)) T(val);}
+#else
+ template <class U> void construct(pointer p, U&& val)
+ {::new(static_cast<void*>(p)) T(std::forward<U>(val));}
+#endif
void destroy(pointer p) {p->~T();}
-
friend bool operator==(const test_allocator& x, const test_allocator& y)
{return x.data_ == y.data_;}
friend bool operator!=(const test_allocator& x, const test_allocator& y)
@@ -140,12 +140,13 @@
{assert(data_ >= 0); --alloc_count; ::operator delete((void*)p); }
size_type max_size() const throw()
{return UINT_MAX / sizeof(T);}
+#if TEST_STD_VER < 11
void construct(pointer p, const T& val)
- {::new(p) T(val);}
-#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
- void construct(pointer p, T&& val)
- {::new(p) T(std::move(val));}
-#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
+ {::new(static_cast<void*>(p)) T(val);}
+#else
+ template <class U> void construct(pointer p, U&& val)
+ {::new(static_cast<void*>(p)) T(std::forward<U>(val));}
+#endif
void destroy(pointer p) {p->~T();}
friend bool operator==(const non_default_test_allocator& x, const non_default_test_allocator& y)
