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f4c1258d56
Some embedded platforms do not wish to support the C library functionality for handling wchar_t because they have no use for it. It makes sense for libc++ to work properly on those platforms, so this commit adds a carve-out of functionality for wchar_t. Unfortunately, unlike some other carve-outs (e.g. random device), this patch touches several parts of the library. However, despite the wide impact of this patch, I still think it is important to support this configuration since it makes it much simpler to port libc++ to some embedded platforms. Differential Revision: https://reviews.llvm.org/D111265
101 lines
3.8 KiB
C++
101 lines
3.8 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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// Make sure that the iostreams are initialized before everything else.
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// This has been an issue when statically linking libc++ in some contexts.
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// See https://llvm.org/PR28954 for details.
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//
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// This test works by checking that std::{cin,cout,cerr} is the same in a
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// static object constructor and in the main function. It dumps the memory of
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// each stream in the static object constructor and compares it with the memory
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// in the main function.
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//
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// The assumption is that if there are no uses of the stream object (such as
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// construction), then its memory must be the same. In the case where the test
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// "fails" and we are actually accessing an uninitialized object when we perform
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// the memcpy, the behavior is technically undefined (so the test could still
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// pass).
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#include <cassert>
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#include <cstring>
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#include <iostream>
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#include "test_macros.h"
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struct Checker {
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char *cerr_mem_dump;
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char *cin_mem_dump;
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char *cout_mem_dump;
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char *clog_mem_dump;
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Checker()
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: cerr_mem_dump(new char[sizeof(std::cerr)])
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, cin_mem_dump(new char[sizeof(std::cin)])
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, cout_mem_dump(new char[sizeof(std::cout)])
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, clog_mem_dump(new char[sizeof(std::clog)])
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{
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std::memcpy(cerr_mem_dump, (char*)&std::cerr, sizeof(std::cerr));
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std::memcpy(cin_mem_dump, (char*)&std::cin, sizeof(std::cin));
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std::memcpy(cout_mem_dump, (char*)&std::cout, sizeof(std::cout));
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std::memcpy(clog_mem_dump, (char*)&std::clog, sizeof(std::clog));
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}
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~Checker() {
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delete[] cerr_mem_dump;
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delete[] cin_mem_dump;
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delete[] cout_mem_dump;
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delete[] clog_mem_dump;
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}
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};
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static Checker check;
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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struct WideChecker {
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char *wcerr_mem_dump;
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char *wcin_mem_dump;
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char *wcout_mem_dump;
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char *wclog_mem_dump;
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WideChecker()
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: wcerr_mem_dump(new char[sizeof(std::wcerr)])
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, wcin_mem_dump(new char[sizeof(std::wcin)])
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, wcout_mem_dump(new char[sizeof(std::wcout)])
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, wclog_mem_dump(new char[sizeof(std::wclog)])
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{
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std::memcpy(wcerr_mem_dump, (char*)&std::wcerr, sizeof(std::wcerr));
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std::memcpy(wcin_mem_dump, (char*)&std::wcin, sizeof(std::wcin));
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std::memcpy(wcout_mem_dump, (char*)&std::wcout, sizeof(std::wcout));
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std::memcpy(wclog_mem_dump, (char*)&std::wclog, sizeof(std::wclog));
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}
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~WideChecker() {
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delete[] wcerr_mem_dump;
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delete[] wcin_mem_dump;
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delete[] wcout_mem_dump;
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delete[] wclog_mem_dump;
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}
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};
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static WideChecker wide_check;
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#endif
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int main(int, char**) {
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assert(std::memcmp(check.cerr_mem_dump, (char const*)&std::cerr, sizeof(std::cerr)) == 0);
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assert(std::memcmp(check.cin_mem_dump, (char const*)&std::cin, sizeof(std::cin)) == 0);
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assert(std::memcmp(check.cout_mem_dump, (char const*)&std::cout, sizeof(std::cout)) == 0);
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assert(std::memcmp(check.clog_mem_dump, (char const*)&std::clog, sizeof(std::clog)) == 0);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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assert(std::memcmp(wide_check.wcerr_mem_dump, (char const*)&std::wcerr, sizeof(std::wcerr)) == 0);
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assert(std::memcmp(wide_check.wcin_mem_dump, (char const*)&std::wcin, sizeof(std::wcin)) == 0);
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assert(std::memcmp(wide_check.wcout_mem_dump, (char const*)&std::wcout, sizeof(std::wcout)) == 0);
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assert(std::memcmp(wide_check.wclog_mem_dump, (char const*)&std::wclog, sizeof(std::wclog)) == 0);
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#endif
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return 0;
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}
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