Update prebuilt Clang to r416183b from Android.

https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef

clang 12.0.5 (based on r416183b) from build 7284624.

Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/include/llvm/Support/AlignOf.h b/linux-x64/clang/include/llvm/Support/AlignOf.h
index d12401f..f586d7f 100644
--- a/linux-x64/clang/include/llvm/Support/AlignOf.h
+++ b/linux-x64/clang/include/llvm/Support/AlignOf.h
@@ -6,140 +6,29 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file defines the AlignedCharArray and AlignedCharArrayUnion classes.
+// This file defines the AlignedCharArrayUnion class.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_ALIGNOF_H
 #define LLVM_SUPPORT_ALIGNOF_H
 
-#include "llvm/Support/Compiler.h"
-#include <cstddef>
+#include <type_traits>
 
 namespace llvm {
 
-/// \struct AlignedCharArray
-/// Helper for building an aligned character array type.
+/// A suitably aligned and sized character array member which can hold elements
+/// of any type.
 ///
-/// This template is used to explicitly build up a collection of aligned
-/// character array types. We have to build these up using a macro and explicit
-/// specialization to cope with MSVC (at least till 2015) where only an
-/// integer literal can be used to specify an alignment constraint. Once built
-/// up here, we can then begin to indirect between these using normal C++
-/// template parameters.
-
-// MSVC requires special handling here.
-#ifndef _MSC_VER
-
-template<std::size_t Alignment, std::size_t Size>
-struct AlignedCharArray {
-  alignas(Alignment) char buffer[Size];
+/// This template is equivalent to std::aligned_union_t<1, ...>, but we cannot
+/// use it due to a bug in the MSVC x86 compiler:
+/// https://github.com/microsoft/STL/issues/1533
+/// Using `alignas` here works around the bug.
+template <typename T, typename... Ts> struct AlignedCharArrayUnion {
+  using AlignedUnion = std::aligned_union_t<1, T, Ts...>;
+  alignas(alignof(AlignedUnion)) char buffer[sizeof(AlignedUnion)];
 };
 
-#else // _MSC_VER
-
-/// Create a type with an aligned char buffer.
-template<std::size_t Alignment, std::size_t Size>
-struct AlignedCharArray;
-
-// We provide special variations of this template for the most common
-// alignments because __declspec(align(...)) doesn't actually work when it is
-// a member of a by-value function argument in MSVC, even if the alignment
-// request is something reasonably like 8-byte or 16-byte. Note that we can't
-// even include the declspec with the union that forces the alignment because
-// MSVC warns on the existence of the declspec despite the union member forcing
-// proper alignment.
-
-template<std::size_t Size>
-struct AlignedCharArray<1, Size> {
-  union {
-    char aligned;
-    char buffer[Size];
-  };
-};
-
-template<std::size_t Size>
-struct AlignedCharArray<2, Size> {
-  union {
-    short aligned;
-    char buffer[Size];
-  };
-};
-
-template<std::size_t Size>
-struct AlignedCharArray<4, Size> {
-  union {
-    int aligned;
-    char buffer[Size];
-  };
-};
-
-template<std::size_t Size>
-struct AlignedCharArray<8, Size> {
-  union {
-    double aligned;
-    char buffer[Size];
-  };
-};
-
-
-// The rest of these are provided with a __declspec(align(...)) and we simply
-// can't pass them by-value as function arguments on MSVC.
-
-#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \
-  template<std::size_t Size> \
-  struct AlignedCharArray<x, Size> { \
-    __declspec(align(x)) char buffer[Size]; \
-  };
-
-LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(16)
-LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(32)
-LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(64)
-LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(128)
-
-#undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
-
-#endif // _MSC_VER
-
-namespace detail {
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-class AlignerImpl {
-  T1 t1; T2 t2; T3 t3; T4 t4; T5 t5; T6 t6; T7 t7; T8 t8; T9 t9; T10 t10;
-
-  AlignerImpl() = delete;
-};
-
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-union SizerImpl {
-  char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)],
-       arr5[sizeof(T5)], arr6[sizeof(T6)], arr7[sizeof(T7)], arr8[sizeof(T8)],
-       arr9[sizeof(T9)], arr10[sizeof(T10)];
-};
-} // end namespace detail
-
-/// This union template exposes a suitably aligned and sized character
-/// array member which can hold elements of any of up to ten types.
-///
-/// These types may be arrays, structs, or any other types. The goal is to
-/// expose a char array buffer member which can be used as suitable storage for
-/// a placement new of any of these types. Support for more than ten types can
-/// be added at the cost of more boilerplate.
-template <typename T1,
-          typename T2 = char, typename T3 = char, typename T4 = char,
-          typename T5 = char, typename T6 = char, typename T7 = char,
-          typename T8 = char, typename T9 = char, typename T10 = char>
-struct AlignedCharArrayUnion : llvm::AlignedCharArray<
-    alignof(llvm::detail::AlignerImpl<T1, T2, T3, T4, T5,
-                                      T6, T7, T8, T9, T10>),
-    sizeof(::llvm::detail::SizerImpl<T1, T2, T3, T4, T5,
-                                     T6, T7, T8, T9, T10>)> {
-};
 } // end namespace llvm
 
 #endif // LLVM_SUPPORT_ALIGNOF_H