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2df59c5068
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
95 lines
2.7 KiB
C++
95 lines
2.7 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++98, c++03
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// <vector>
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// void swap(vector& c)
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// noexcept(!allocator_type::propagate_on_container_swap::value ||
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// __is_nothrow_swappable<allocator_type>::value);
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//
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// In C++17, the standard says that swap shall have:
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// noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
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// allocator_traits<Allocator>::is_always_equal::value);
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// This tests a conforming extension
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#include <vector>
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#include <utility>
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#include <cassert>
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#include "test_macros.h"
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#include "test_allocator.h"
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template <class T>
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struct some_alloc
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{
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typedef T value_type;
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some_alloc() {}
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some_alloc(const some_alloc&);
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void deallocate(void*, unsigned) {}
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typedef std::true_type propagate_on_container_swap;
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};
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template <class T>
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struct some_alloc2
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{
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typedef T value_type;
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some_alloc2() {}
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some_alloc2(const some_alloc2&);
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void deallocate(void*, unsigned) {}
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typedef std::false_type propagate_on_container_swap;
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typedef std::true_type is_always_equal;
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};
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int main(int, char**)
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{
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#if defined(_LIBCPP_VERSION)
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{
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typedef std::vector<bool> C;
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static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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}
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{
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typedef std::vector<bool, test_allocator<bool>> C;
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static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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}
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{
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typedef std::vector<bool, other_allocator<bool>> C;
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static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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}
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#endif // _LIBCPP_VERSION
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{
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#if TEST_STD_VER >= 14
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#if defined(_LIBCPP_VERSION)
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// In C++14, if POCS is set, swapping the allocator is required not to throw
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typedef std::vector<bool, some_alloc<bool>> C;
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static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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#endif // _LIBCPP_VERSION
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#else
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typedef std::vector<bool, some_alloc<bool>> C;
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static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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#endif
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}
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#if TEST_STD_VER >= 14
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#if defined(_LIBCPP_VERSION)
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{
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typedef std::vector<bool, some_alloc2<bool>> C;
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// if the allocators are always equal, then the swap can be noexcept
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static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
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}
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#endif // _LIBCPP_VERSION
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#endif
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return 0;
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}
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