From 0ec57bf7b18e8918dd8ced007a88467b798677c6 Mon Sep 17 00:00:00 2001 From: Jordan Rupprecht Date: Wed, 10 May 2023 15:43:37 -0700 Subject: [libc++] Consistently enable __CORRECT_ISO_CPP_WCHAR_H_PROTO in mbstate. In libc++'s `wchar.h`, before we forward to the system `wchar.h`, we set `__CORRECT_ISO_CPP_WCHAR_H_PROTO` to ensure it defines the correct signature (e.g. `extern "C++" const wchar_t *wmemchr` and not `extern wchar_t *wmemchr`). After D148542, there are cases where we include the system `wchar.h` from within `__mbstate_t.h` without setting that, and so we get a function type mismatch if we transitively include `wchar.h` through multiple headers in a modules-enabled build. Consistently setting it here resolves those build errors. Alternative 1: we could put this in `__config` instead. I chose to put it here for a more limited scope. Alternative 2: we could patch `wchar.h` itself to work correctly and remove references `__CORRECT_ISO_CPP_WCHAR_H_PROTO` from libc++ entirely. It does already set it, but with an additional condition that it is being built by GCC >= 4.4. Clang does pretend to be GCC via `__GNUC__` etc. which can be controlled via `-fgnuc-version` command line flags, but that might have other consequences. Reviewed By: ldionne, #libc, MaskRay Differential Revision: https://reviews.llvm.org/D150015 --- libcxx/include/__mbstate_t.h | 8 +++++++ libcxx/include/wchar.h | 2 ++ .../cwchar_include_order1.compile.verify.cpp | 25 ++++++++++++++++++++++ .../cwchar_include_order2.compile.verify.cpp | 25 ++++++++++++++++++++++ 4 files changed, 60 insertions(+) create mode 100644 libcxx/test/std/strings/c.strings/cwchar_include_order1.compile.verify.cpp create mode 100644 libcxx/test/std/strings/c.strings/cwchar_include_order2.compile.verify.cpp (limited to 'libcxx') diff --git a/libcxx/include/__mbstate_t.h b/libcxx/include/__mbstate_t.h index d793787fa0cd..000af71119f4 100644 --- a/libcxx/include/__mbstate_t.h +++ b/libcxx/include/__mbstate_t.h @@ -27,6 +27,14 @@ // This does not define std::mbstate_t -- this only brings in the declaration // in the global namespace. +// We define this here to support older versions of glibc that do +// not define this for clang. This is also set in libc++'s header, +// and we need to do so here too to avoid a different function signature given +// a different include order. +#ifdef __cplusplus +# define __CORRECT_ISO_CPP_WCHAR_H_PROTO +#endif + #if __has_include() # include // works on most Unixes #elif __has_include() diff --git a/libcxx/include/wchar.h b/libcxx/include/wchar.h index db624cea2bee..eeccf3e937ff 100644 --- a/libcxx/include/wchar.h +++ b/libcxx/include/wchar.h @@ -116,6 +116,8 @@ size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len, # pragma GCC system_header #endif +// We define this here to support older versions of glibc that do +// not define this for clang. #ifdef __cplusplus #define __CORRECT_ISO_CPP_WCHAR_H_PROTO #endif diff --git a/libcxx/test/std/strings/c.strings/cwchar_include_order1.compile.verify.cpp b/libcxx/test/std/strings/c.strings/cwchar_include_order1.compile.verify.cpp new file mode 100644 index 000000000000..4b5460a54859 --- /dev/null +++ b/libcxx/test/std/strings/c.strings/cwchar_include_order1.compile.verify.cpp @@ -0,0 +1,25 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// + +// XFAIL: no-wide-characters + +// Tests that include ordering does not affect the definition of wcsstr. +// See: https://llvm.org/PR62638 + +// clang-format off +#include +#include +// clang-format on + +void func() { + wchar_t* v1; + const wchar_t* cv2 = L"/"; + v1 = wcsstr(cv2, L"/"); // expected-error {{assigning to 'wchar_t *' from 'const wchar_t *' discards qualifiers}} +} diff --git a/libcxx/test/std/strings/c.strings/cwchar_include_order2.compile.verify.cpp b/libcxx/test/std/strings/c.strings/cwchar_include_order2.compile.verify.cpp new file mode 100644 index 000000000000..0222ac018d68 --- /dev/null +++ b/libcxx/test/std/strings/c.strings/cwchar_include_order2.compile.verify.cpp @@ -0,0 +1,25 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// + +// XFAIL: no-wide-characters + +// Tests that include ordering does not affect the definition of wcsstr. +// See: https://llvm.org/PR62638 + +// clang-format off +#include +#include +// clang-format on + +void func() { + wchar_t* v1; + const wchar_t* cv2 = L"/"; + v1 = wcsstr(cv2, L"/"); // expected-error {{assigning to 'wchar_t *' from 'const wchar_t *' discards qualifiers}} +} -- cgit v1.2.1