LLVM  13.0.0git
AlignOf.h
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1 //===--- AlignOf.h - Portable calculation of type alignment -----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the AlignedCharArrayUnion class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_SUPPORT_ALIGNOF_H
14 #define LLVM_SUPPORT_ALIGNOF_H
15 
16 #include <type_traits>
17 
18 namespace llvm {
19 
20 /// A suitably aligned and sized character array member which can hold elements
21 /// of any type.
22 ///
23 /// This template is equivalent to std::aligned_union_t<1, ...>, but we cannot
24 /// use it due to a bug in the MSVC x86 compiler:
25 /// https://github.com/microsoft/STL/issues/1533
26 /// Using `alignas` here works around the bug.
27 template <typename T, typename... Ts> struct AlignedCharArrayUnion {
28  using AlignedUnion = std::aligned_union_t<1, T, Ts...>;
29  alignas(alignof(AlignedUnion)) char buffer[sizeof(AlignedUnion)];
30 };
31 
32 } // end namespace llvm
33 
34 #endif // LLVM_SUPPORT_ALIGNOF_H
llvm
Definition: AllocatorList.h:23
llvm::AlignedCharArrayUnion< detail::DenseSetPair< ValueT >[InlineBuckets], LargeRep >::AlignedUnion
std::aligned_union_t< 1, detail::DenseSetPair< ValueT >, Ts... > AlignedUnion
Definition: AlignOf.h:28
T
#define T
Definition: Mips16ISelLowering.cpp:341
llvm::AlignedCharArrayUnion
A suitably aligned and sized character array member which can hold elements of any type.
Definition: AlignOf.h:27
llvm::AlignedCharArrayUnion::buffer
char buffer[sizeof(AlignedUnion)]
Definition: AlignOf.h:29