Make std::get_temporary_buffer respect overaligned types when possible
Patch by Chris Kennelly!
Differential Revision: https://reviews.llvm.org/D41746
llvm-svn: 324020
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 4e3195c9b37dea4a945480576ace65986a56b773
diff --git a/include/memory b/include/memory
index 2273731..2d9d75f 100644
--- a/include/memory
+++ b/include/memory
@@ -2004,7 +2004,38 @@
__n = __m;
while (__n > 0)
{
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+#if defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+ if (std::alignment_of<_Tp>::value > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+#else
+ if (std::alignment_of<_Tp>::value >
+ std::alignment_of<std::max_align_t>::value)
+#endif
+ {
+ std::align_val_t __al =
+ std::align_val_t(std::alignment_of<_Tp>::value);
+ __r.first = static_cast<_Tp*>(::operator new(
+ __n * sizeof(_Tp), __al, nothrow));
+ } else {
+ __r.first = static_cast<_Tp*>(::operator new(
+ __n * sizeof(_Tp), nothrow));
+ }
+#else
+#if defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+ if (std::alignment_of<_Tp>::value > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+#else
+ if (std::alignment_of<_Tp>::value >
+ std::alignment_of<std::max_align_t>::value)
+#endif
+ {
+ // Since aligned operator new is unavailable, return an empty
+ // buffer rather than one with invalid alignment.
+ return __r;
+ }
+
__r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow));
+#endif
+
if (__r.first)
{
__r.second = __n;
@@ -2017,7 +2048,23 @@
template <class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
-void return_temporary_buffer(_Tp* __p) _NOEXCEPT {::operator delete(__p);}
+void return_temporary_buffer(_Tp* __p) _NOEXCEPT
+{
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+#if defined(__STDCPP_DEFAULT_NEW_ALIGNMENT__)
+ if (std::alignment_of<_Tp>::value > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+#else
+ if (std::alignment_of<_Tp>::value >
+ std::alignment_of<std::max_align_t>::value)
+#endif
+ {
+ std::align_val_t __al = std::align_val_t(std::alignment_of<_Tp>::value);
+ ::operator delete(__p, __al);
+ return;
+ }
+#endif
+ ::operator delete(__p);
+}
#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
template <class _Tp>
diff --git a/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp b/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
new file mode 100644
index 0000000..6476015
--- /dev/null
+++ b/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <memory>
+
+// template <class T>
+// pair<T*, ptrdiff_t>
+// get_temporary_buffer(ptrdiff_t n);
+//
+// template <class T>
+// void
+// return_temporary_buffer(T* p);
+
+#include <memory>
+#include <cassert>
+
+struct alignas(32) A {
+ int field;
+};
+
+int main()
+{
+ std::pair<A*, std::ptrdiff_t> ip = std::get_temporary_buffer<A>(5);
+ assert(!(ip.first == nullptr) ^ (ip.second == 0));
+ assert(reinterpret_cast<uintptr_t>(ip.first) % alignof(A) == 0);
+ std::return_temporary_buffer(ip.first);
+}