зеркало из https://github.com/mozilla/gecko-dev.git
64 строки
2.7 KiB
C++
64 строки
2.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
* You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#include "mozilla/Pair.h"
|
|
|
|
using mozilla::Pair;
|
|
|
|
// Sizes aren't part of the guaranteed Pair interface, but we want to verify our
|
|
// attempts at compactness through EBO are moderately functional, *somewhere*.
|
|
#define INSTANTIATE(T1, T2, name, size) \
|
|
Pair<T1, T2> name##_1(T1(0), T2(0)); \
|
|
static_assert(sizeof(name##_1.first()) > 0, \
|
|
"first method should work on Pair<" #T1 ", " #T2 ">"); \
|
|
static_assert(sizeof(name##_1.second()) > 0, \
|
|
"second method should work on Pair<" #T1 ", " #T2 ">"); \
|
|
static_assert(sizeof(name##_1) == (size), \
|
|
"Pair<" #T1 ", " #T2 "> has an unexpected size"); \
|
|
Pair<T2, T1> name##_2(T2(0), T1(0)); \
|
|
static_assert(sizeof(name##_2.first()) > 0, \
|
|
"first method should work on Pair<" #T2 ", " #T1 ">"); \
|
|
static_assert(sizeof(name##_2.second()) > 0, \
|
|
"second method should work on Pair<" #T2 ", " #T1 ">"); \
|
|
static_assert(sizeof(name##_2) == (size), \
|
|
"Pair<" #T2 ", " #T1 "> has an unexpected size");
|
|
|
|
INSTANTIATE(int, int, prim1, 2 * sizeof(int));
|
|
INSTANTIATE(int, long, prim2, 2 * sizeof(long));
|
|
|
|
struct EmptyClass { explicit EmptyClass(int) {} };
|
|
struct NonEmpty { char mC; explicit NonEmpty(int) {} };
|
|
|
|
INSTANTIATE(int, EmptyClass, both1, sizeof(int));
|
|
INSTANTIATE(int, NonEmpty, both2, 2 * sizeof(int));
|
|
INSTANTIATE(EmptyClass, NonEmpty, both3, 1);
|
|
|
|
struct A { char dummy; explicit A(int) {} };
|
|
struct B : A { explicit B(int aI) : A(aI) {} };
|
|
|
|
INSTANTIATE(A, A, class1, 2);
|
|
INSTANTIATE(A, B, class2, 2);
|
|
INSTANTIATE(A, EmptyClass, class3, 1);
|
|
|
|
struct OtherEmpty : EmptyClass { explicit OtherEmpty(int aI) : EmptyClass(aI) {} };
|
|
|
|
// C++11 requires distinct objects of the same type, within the same "most
|
|
// derived object", to have different addresses. Pair allocates its elements as
|
|
// two bases, a base and a member, or two members. If the two elements have
|
|
// non-zero size or are unrelated, no big deal. But if they're both empty and
|
|
// related, something -- possibly both -- must be inflated. Exactly which are
|
|
// inflated depends which PairHelper specialization is used. We could
|
|
// potentially assert something about size for this case, but whatever we could
|
|
// assert would be very finicky. Plus it's two empty classes -- hardly likely.
|
|
// So don't bother trying to assert anything about this case.
|
|
//INSTANTIATE(EmptyClass, OtherEmpty, class4, ...something finicky...);
|
|
|
|
int
|
|
main()
|
|
{
|
|
return 0;
|
|
}
|