1 //===--- AlignOf.h - Portable calculation of type alignment -----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the AlignOf function that computes alignments for
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_ALIGNOF_H
16 #define LLVM_SUPPORT_ALIGNOF_H
21 struct AlignmentCalcImpl {
25 AlignmentCalcImpl() {} // Never instantiate.
28 /// AlignOf - A templated class that contains an enum value representing
29 /// the alignment of the template argument. For example,
30 /// AlignOf<int>::Alignment represents the alignment of type "int". The
31 /// alignment calculated is the minimum alignment, and not necessarily
32 /// the "desired" alignment returned by GCC's __alignof__ (for example). Note
33 /// that because the alignment is an enum value, it can be used as a
34 /// compile-time constant (e.g., for template instantiation).
37 enum { Alignment = sizeof(AlignmentCalcImpl<T>) - sizeof(T) };
40 /// alignof - A templated function that returns the mininum alignment of
41 /// of a type. This provides no extra functionality beyond the AlignOf
42 /// class besides some cosmetic cleanliness. Example usage:
43 /// alignof<int>() returns the alignment of an int.
45 static inline unsigned alignof() { return AlignOf<T>::Alignment; }
47 } // end namespace llvm