JF Bastien 2df59c5068 Support tests in freestanding
Summary:
Freestanding is *weird*. The standard allows it to differ in a bunch of odd
manners from regular C++, and the committee would like to improve that
situation. I'd like to make libc++ behave better with what freestanding should
be, so that it can be a tool we use in improving the standard. To do that we
need to try stuff out, both with "freestanding the language mode" and
"freestanding the library subset".

Let's start with the super basic: run the libc++ tests in freestanding, using
clang as the compiler, and see what works. The easiest hack to do this:

In utils/libcxx/test/config.py add:

  self.cxx.compile_flags += ['-ffreestanding']

Run the tests and they all fail.

Why? Because in freestanding `main` isn't special. This "not special" property
has two effects: main doesn't get mangled, and main isn't allowed to omit its
`return` statement. The first means main gets mangled and the linker can't
create a valid executable for us to test. The second means we spew out warnings
(ew) and the compiler doesn't insert the `return` we omitted, and main just
falls of the end and does whatever undefined behavior (if you're luck, ud2
leading to non-zero return code).

Let's start my work with the basics. This patch changes all libc++ tests to
declare `main` as `int main(int, char**` so it mangles consistently (enabling us
to declare another `extern "C"` main for freestanding which calls the mangled
one), and adds `return 0;` to all places where it was missing. This touches 6124
files, and I apologize.

The former was done with The Magic Of Sed.

The later was done with a (not quite correct but decent) clang tool:

  https://gist.github.com/jfbastien/793819ff360baa845483dde81170feed

This works for most tests, though I did have to adjust a few places when e.g.
the test runs with `-x c`, macros are used for main (such as for the filesystem
tests), etc.

Once this is in we can create a freestanding bot which will prevent further
regressions. After that, we can start the real work of supporting C++
freestanding fairly well in libc++.

<rdar://problem/47754795>

Reviewers: ldionne, mclow.lists, EricWF

Subscribers: christof, jkorous, dexonsmith, arphaman, miyuki, libcxx-commits

Differential Revision: https://reviews.llvm.org/D57624

llvm-svn: 353086
2019-02-04 20:31:13 +00:00

278 lines
7.9 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14
// <variant>
// template <class ...Types>
// constexpr bool
// operator==(variant<Types...> const&, variant<Types...> const&) noexcept;
//
// template <class ...Types>
// constexpr bool
// operator!=(variant<Types...> const&, variant<Types...> const&) noexcept;
//
// template <class ...Types>
// constexpr bool
// operator<(variant<Types...> const&, variant<Types...> const&) noexcept;
//
// template <class ...Types>
// constexpr bool
// operator>(variant<Types...> const&, variant<Types...> const&) noexcept;
//
// template <class ...Types>
// constexpr bool
// operator<=(variant<Types...> const&, variant<Types...> const&) noexcept;
//
// template <class ...Types>
// constexpr bool
// operator>=(variant<Types...> const&, variant<Types...> const&) noexcept;
#include <cassert>
#include <type_traits>
#include <utility>
#include <variant>
#include "test_macros.h"
#ifndef TEST_HAS_NO_EXCEPTIONS
struct MakeEmptyT {
MakeEmptyT() = default;
MakeEmptyT(MakeEmptyT &&) { throw 42; }
MakeEmptyT &operator=(MakeEmptyT &&) { throw 42; }
};
inline bool operator==(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
inline bool operator!=(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
inline bool operator<(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
inline bool operator<=(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
inline bool operator>(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
inline bool operator>=(const MakeEmptyT &, const MakeEmptyT &) {
assert(false);
return false;
}
template <class Variant> void makeEmpty(Variant &v) {
Variant v2(std::in_place_type<MakeEmptyT>);
try {
v = std::move(v2);
assert(false);
} catch (...) {
assert(v.valueless_by_exception());
}
}
#endif // TEST_HAS_NO_EXCEPTIONS
struct MyBool {
bool value;
constexpr explicit MyBool(bool v) : value(v) {}
constexpr operator bool() const noexcept { return value; }
};
struct ComparesToMyBool {
int value = 0;
};
inline constexpr MyBool operator==(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value == RHS.value);
}
inline constexpr MyBool operator!=(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value != RHS.value);
}
inline constexpr MyBool operator<(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value < RHS.value);
}
inline constexpr MyBool operator<=(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value <= RHS.value);
}
inline constexpr MyBool operator>(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value > RHS.value);
}
inline constexpr MyBool operator>=(const ComparesToMyBool& LHS, const ComparesToMyBool& RHS) noexcept {
return MyBool(LHS.value >= RHS.value);
}
template <class T1, class T2>
void test_equality_basic() {
{
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{42});
constexpr V v2(std::in_place_index<0>, T1{42});
static_assert(v1 == v2, "");
static_assert(v2 == v1, "");
static_assert(!(v1 != v2), "");
static_assert(!(v2 != v1), "");
}
{
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{42});
constexpr V v2(std::in_place_index<0>, T1{43});
static_assert(!(v1 == v2), "");
static_assert(!(v2 == v1), "");
static_assert(v1 != v2, "");
static_assert(v2 != v1, "");
}
{
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{42});
constexpr V v2(std::in_place_index<1>, T2{42});
static_assert(!(v1 == v2), "");
static_assert(!(v2 == v1), "");
static_assert(v1 != v2, "");
static_assert(v2 != v1, "");
}
{
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<1>, T2{42});
constexpr V v2(std::in_place_index<1>, T2{42});
static_assert(v1 == v2, "");
static_assert(v2 == v1, "");
static_assert(!(v1 != v2), "");
static_assert(!(v2 != v1), "");
}
}
void test_equality() {
test_equality_basic<int, long>();
test_equality_basic<ComparesToMyBool, int>();
test_equality_basic<int, ComparesToMyBool>();
test_equality_basic<ComparesToMyBool, ComparesToMyBool>();
#ifndef TEST_HAS_NO_EXCEPTIONS
{
using V = std::variant<int, MakeEmptyT>;
V v1;
V v2;
makeEmpty(v2);
assert(!(v1 == v2));
assert(!(v2 == v1));
assert(v1 != v2);
assert(v2 != v1);
}
{
using V = std::variant<int, MakeEmptyT>;
V v1;
makeEmpty(v1);
V v2;
assert(!(v1 == v2));
assert(!(v2 == v1));
assert(v1 != v2);
assert(v2 != v1);
}
{
using V = std::variant<int, MakeEmptyT>;
V v1;
makeEmpty(v1);
V v2;
makeEmpty(v2);
assert(v1 == v2);
assert(v2 == v1);
assert(!(v1 != v2));
assert(!(v2 != v1));
}
#endif
}
template <class Var>
constexpr bool test_less(const Var &l, const Var &r, bool expect_less,
bool expect_greater) {
static_assert(std::is_same_v<decltype(l < r), bool>, "");
static_assert(std::is_same_v<decltype(l <= r), bool>, "");
static_assert(std::is_same_v<decltype(l > r), bool>, "");
static_assert(std::is_same_v<decltype(l >= r), bool>, "");
return ((l < r) == expect_less) && (!(l >= r) == expect_less) &&
((l > r) == expect_greater) && (!(l <= r) == expect_greater);
}
template <class T1, class T2>
void test_relational_basic() {
{ // same index, same value
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{1});
constexpr V v2(std::in_place_index<0>, T1{1});
static_assert(test_less(v1, v2, false, false), "");
}
{ // same index, value < other_value
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{0});
constexpr V v2(std::in_place_index<0>, T1{1});
static_assert(test_less(v1, v2, true, false), "");
}
{ // same index, value > other_value
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{1});
constexpr V v2(std::in_place_index<0>, T1{0});
static_assert(test_less(v1, v2, false, true), "");
}
{ // LHS.index() < RHS.index()
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<0>, T1{0});
constexpr V v2(std::in_place_index<1>, T2{0});
static_assert(test_less(v1, v2, true, false), "");
}
{ // LHS.index() > RHS.index()
using V = std::variant<T1, T2>;
constexpr V v1(std::in_place_index<1>, T2{0});
constexpr V v2(std::in_place_index<0>, T1{0});
static_assert(test_less(v1, v2, false, true), "");
}
}
void test_relational() {
test_relational_basic<int, long>();
test_relational_basic<ComparesToMyBool, int>();
test_relational_basic<int, ComparesToMyBool>();
test_relational_basic<ComparesToMyBool, ComparesToMyBool>();
#ifndef TEST_HAS_NO_EXCEPTIONS
{ // LHS.index() < RHS.index(), RHS is empty
using V = std::variant<int, MakeEmptyT>;
V v1;
V v2;
makeEmpty(v2);
assert(test_less(v1, v2, false, true));
}
{ // LHS.index() > RHS.index(), LHS is empty
using V = std::variant<int, MakeEmptyT>;
V v1;
makeEmpty(v1);
V v2;
assert(test_less(v1, v2, true, false));
}
{ // LHS.index() == RHS.index(), LHS and RHS are empty
using V = std::variant<int, MakeEmptyT>;
V v1;
makeEmpty(v1);
V v2;
makeEmpty(v2);
assert(test_less(v1, v2, false, false));
}
#endif
}
int main(int, char**) {
test_equality();
test_relational();
return 0;
}