[libc++] Remove test suite workarounds on Apple with old Clangs

[ldionne]

Summary

In 5fd17ab, we worked around the Apple system headers not providing
const-correct overloads for some <string.h> functions. However, that
required an attribute that was only present in recent Clangs at the
time. We can now assume that all supported Clang versions on Apple
platforms do support that attribute.

[• Quuxplusone]

LGTM!
Bonus tech-debt points if you want to make a followup NFC commit to consistently use ASSERT_SAME_TYPE and, like, const wchar_t *cws instead of manual casting everywhere.

[ldionne]

CI tests passed but failed to update in Phab. Shippping now.

In D100477#2689486, @Quuxplusone wrote:

LGTM!
Bonus tech-debt points if you want to make a followup NFC commit to consistently use ASSERT_SAME_TYPE and, like, const wchar_t *cws instead of manual casting everywhere.

Yeah, I'll do that in a follow-up NFC. Thanks!

libcxx/test/std/depr/depr.c.headers/string_h.pass.cpp

int main(int, char**)
     static_assert((std::is_same<decltype(strcat(cp, cpc)), char*>::value), "");
     static_assert((std::is_same<decltype(strncat(cp, cpc, s)), char*>::value), "");
     static_assert((std::is_same<decltype(memcmp(vpc, vpc, s)), int>::value), "");
     static_assert((std::is_same<decltype(strcmp(cpc, cpc)), int>::value), "");
     static_assert((std::is_same<decltype(strncmp(cpc, cpc, s)), int>::value), "");
     static_assert((std::is_same<decltype(strcoll(cpc, cpc)), int>::value), "");
     static_assert((std::is_same<decltype(strxfrm(cp, cpc, s)), size_t>::value), "");
     static_assert((std::is_same<decltype(memchr(vp, 0, s)), void*>::value), "");
+    static_assert((std::is_same<decltype(memchr(vpc, 0, s)), const void*>::value), "");
     static_assert((std::is_same<decltype(strchr(cp, 0)), char*>::value), "");
+    static_assert((std::is_same<decltype(strchr(cpc, 0)), const char*>::value), "");
     static_assert((std::is_same<decltype(strcspn(cpc, cpc)), size_t>::value), "");
     static_assert((std::is_same<decltype(strpbrk(cp, cpc)), char*>::value), "");
+    static_assert((std::is_same<decltype(strpbrk(cpc, cpc)), const char*>::value), "");
     static_assert((std::is_same<decltype(strrchr(cp, 0)), char*>::value), "");
+    static_assert((std::is_same<decltype(strrchr(cpc, 0)), const char*>::value), "");
     static_assert((std::is_same<decltype(strspn(cpc, cpc)), size_t>::value), "");
     static_assert((std::is_same<decltype(strstr(cp, cpc)), char*>::value), "");
+    static_assert((std::is_same<decltype(strstr(cpc, cpc)), const char*>::value), "");
 #ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
     static_assert((std::is_same<decltype(strtok(cp, cpc)), char*>::value), "");
 #endif
     static_assert((std::is_same<decltype(memset(vp, 0, s)), void*>::value), "");
     static_assert((std::is_same<decltype(strerror(0)), char*>::value), "");
     static_assert((std::is_same<decltype(strlen(cpc)), size_t>::value), "");
 
-    // These tests fail on systems whose C library doesn't provide a correct overload
-    // set for strchr, strpbrk, strrchr, strstr, and memchr, unless the compiler is
-    // a suitably recent version of Clang.
-#if !defined(__APPLE__) || defined(_LIBCPP_PREFERRED_OVERLOAD)
-    static_assert((std::is_same<decltype(strchr(cpc, 0)), const char*>::value), "");
-    static_assert((std::is_same<decltype(strpbrk(cpc, cpc)), const char*>::value), "");
-    static_assert((std::is_same<decltype(strrchr(cpc, 0)), const char*>::value), "");
-    static_assert((std::is_same<decltype(strstr(cpc, cpc)), const char*>::value), "");
-    static_assert((std::is_same<decltype(memchr(vpc, 0, s)), const void*>::value), "");
-#endif
-
     return 0;
 }

libcxx/test/std/depr/depr.c.headers/wchar_h.pass.cpp

//    characters and wide characters
     static_assert((std::is_same<decltype(wcsncpy(ws, L"", s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcscat(ws, L"")), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsncat(ws, L"", s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcscmp(L"", L"")), int>::value), "");
     static_assert((std::is_same<decltype(wcscoll(L"", L"")), int>::value), "");
     static_assert((std::is_same<decltype(wcsncmp(L"", L"", s)), int>::value), "");
     static_assert((std::is_same<decltype(wcsxfrm(ws, L"", s)), size_t>::value), "");
     static_assert((std::is_same<decltype(wcschr((wchar_t*)0, L' ')), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wcschr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcscspn(L"", L"")), size_t>::value), "");
     static_assert((std::is_same<decltype(wcslen(L"")), size_t>::value), "");
     static_assert((std::is_same<decltype(wcspbrk((wchar_t*)0, L"")), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wcspbrk((const wchar_t*)0, L"")), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsrchr((wchar_t*)0, L' ')), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wcsrchr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsspn(L"", L"")), size_t>::value), "");
     static_assert((std::is_same<decltype(wcsstr((wchar_t*)0, L"")), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wcsstr((const wchar_t*)0, L"")), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcstok(ws, L"", (wchar_t**)0)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemchr((wchar_t*)0, L' ', s)), wchar_t*>::value), "");
+    static_assert((std::is_same<decltype(wmemchr((const wchar_t*)0, L' ', s)), const wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemcmp(L"", L"", s)), int>::value), "");
     static_assert((std::is_same<decltype(wmemcpy(ws, L"", s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemmove(ws, L"", s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wmemset(ws, L' ', s)), wchar_t*>::value), "");
     static_assert((std::is_same<decltype(wcsftime(ws, s, L"", tm)), size_t>::value), "");
     static_assert((std::is_same<decltype(btowc(0)), wint_t>::value), "");
     static_assert((std::is_same<decltype(wctob(w)), int>::value), "");
     static_assert((std::is_same<decltype(mbsinit(&mb)), int>::value), "");
     static_assert((std::is_same<decltype(mbrlen("", s, &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(mbrtowc(ws, "", s, &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(wcrtomb(ns, L' ', &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(mbsrtowcs(ws, (const char**)0, s, &mb)), size_t>::value), "");
     static_assert((std::is_same<decltype(wcsrtombs(ns, (const wchar_t**)0, s, &mb)), size_t>::value), "");
 
-    // These tests fail on systems whose C library doesn't provide a correct overload
-    // set for wcschr, wcspbrk, wcsrchr, wcsstr, and wmemchr, unless the compiler is
-    // a suitably recent version of Clang.
-#if !defined(__APPLE__) || defined(_LIBCPP_PREFERRED_OVERLOAD)
-    static_assert((std::is_same<decltype(wcschr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
-    static_assert((std::is_same<decltype(wcspbrk((const wchar_t*)0, L"")), const wchar_t*>::value), "");
-    static_assert((std::is_same<decltype(wcsrchr((const wchar_t*)0, L' ')), const wchar_t*>::value), "");
-    static_assert((std::is_same<decltype(wcsstr((const wchar_t*)0, L"")), const wchar_t*>::value), "");
-    static_assert((std::is_same<decltype(wmemchr((const wchar_t*)0, L' ', s)), const wchar_t*>::value), "");
-#endif
-
 #ifndef _LIBCPP_HAS_NO_STDIN
     static_assert((std::is_same<decltype(getwchar()), wint_t>::value), "");
     static_assert((std::is_same<decltype(vwscanf(L"", va)), int>::value), "");
     static_assert((std::is_same<decltype(wscanf(L"")), int>::value), "");
 #endif
 
 #ifndef _LIBCPP_HAS_NO_STDOUT
     static_assert((std::is_same<decltype(putwchar(L' ')), wint_t>::value), "");
     static_assert((std::is_same<decltype(vwprintf(L"", va)), int>::value), "");
     static_assert((std::is_same<decltype(wprintf(L"")), int>::value), "");
 #endif
 
     return 0;
 }

libcxx/test/std/strings/c.strings/cstring.pass.cpp

int main(int, char**)
     ASSERT_SAME_TYPE(char*,       decltype(std::strcat(cp, cpc)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strncat(cp, cpc, s)));
     ASSERT_SAME_TYPE(int,         decltype(std::memcmp(vpc, vpc, s)));
     ASSERT_SAME_TYPE(int,         decltype(std::strcmp(cpc, cpc)));
     ASSERT_SAME_TYPE(int,         decltype(std::strncmp(cpc, cpc, s)));
     ASSERT_SAME_TYPE(int,         decltype(std::strcoll(cpc, cpc)));
     ASSERT_SAME_TYPE(std::size_t, decltype(std::strxfrm(cp, cpc, s)));
     ASSERT_SAME_TYPE(void*,       decltype(std::memchr(vp, 0, s)));
+    ASSERT_SAME_TYPE(const void*, decltype(std::memchr(vpc, 0, s)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strchr(cp, 0)));
+    ASSERT_SAME_TYPE(const char*, decltype(std::strchr(cpc, 0)));
     ASSERT_SAME_TYPE(std::size_t, decltype(std::strcspn(cpc, cpc)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strpbrk(cp, cpc)));
+    ASSERT_SAME_TYPE(const char*, decltype(std::strpbrk(cpc, cpc)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strrchr(cp, 0)));
+    ASSERT_SAME_TYPE(const char*, decltype(std::strrchr(cpc, 0)));
     ASSERT_SAME_TYPE(std::size_t, decltype(std::strspn(cpc, cpc)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strstr(cp, cpc)));
+    ASSERT_SAME_TYPE(const char*, decltype(std::strstr(cpc, cpc)));
 #ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
     ASSERT_SAME_TYPE(char*,       decltype(std::strtok(cp, cpc)));
 #endif
     ASSERT_SAME_TYPE(void*,       decltype(std::memset(vp, 0, s)));
     ASSERT_SAME_TYPE(char*,       decltype(std::strerror(0)));
     ASSERT_SAME_TYPE(std::size_t, decltype(std::strlen(cpc)));
 
-    // These tests fail on systems whose C library doesn't provide a correct overload
-    // set for strchr, strpbrk, strrchr, strstr, and memchr, unless the compiler is
-    // a suitably recent version of Clang.
-#if !defined(__APPLE__) || defined(_LIBCPP_PREFERRED_OVERLOAD)
-    ASSERT_SAME_TYPE(const void*, decltype(std::memchr(vpc, 0, s)));
-    ASSERT_SAME_TYPE(const char*, decltype(std::strchr(cpc, 0)));
-    ASSERT_SAME_TYPE(const char*, decltype(std::strpbrk(cpc, cpc)));
-    ASSERT_SAME_TYPE(const char*, decltype(std::strrchr(cpc, 0)));
-    ASSERT_SAME_TYPE(const char*, decltype(std::strstr(cpc, cpc)));
-#endif
-
     return 0;
 }

libcxx/test/std/strings/c.strings/cwchar.pass.cpp

int main(int, char**)
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcsncpy(ws, L"", s)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcscat(ws, L"")));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcsncat(ws, L"", s)));
     ASSERT_SAME_TYPE(int,                decltype(std::wcscmp(L"", L"")));
     ASSERT_SAME_TYPE(int,                decltype(std::wcscoll(L"", L"")));
     ASSERT_SAME_TYPE(int,                decltype(std::wcsncmp(L"", L"", s)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcsxfrm(ws, L"", s)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcschr((wchar_t*)0, L' ')));
+    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcschr((const wchar_t*)0, L' ')));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcscspn(L"", L"")));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcslen(L"")));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcspbrk((wchar_t*)0, L"")));
+    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcspbrk((const wchar_t*)0, L"")));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcsrchr((wchar_t*)0, L' ')));
+    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcsrchr((const wchar_t*)0, L' ')));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcsspn(L"", L"")));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcsstr((wchar_t*)0, L"")));
+    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcsstr((const wchar_t*)0, L"")));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wcstok(ws, L"", (wchar_t**)0)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wmemchr((wchar_t*)0, L' ', s)));
+    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wmemchr((const wchar_t*)0, L' ', s)));
     ASSERT_SAME_TYPE(int,                decltype(std::wmemcmp(L"", L"", s)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wmemcpy(ws, L"", s)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wmemmove(ws, L"", s)));
     ASSERT_SAME_TYPE(wchar_t*,           decltype(std::wmemset(ws, L' ', s)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcsftime(ws, s, L"", tm)));
     ASSERT_SAME_TYPE(wint_t,             decltype(std::btowc(0)));
     ASSERT_SAME_TYPE(int,                decltype(std::wctob(w)));
     ASSERT_SAME_TYPE(int,                decltype(std::mbsinit(&mb)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::mbrlen("", s, &mb)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::mbrtowc(ws, "", s, &mb)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcrtomb(ns, L' ', &mb)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::mbsrtowcs(ws, (const char**)0, s, &mb)));
     ASSERT_SAME_TYPE(std::size_t,        decltype(std::wcsrtombs(ns, (const wchar_t**)0, s, &mb)));
 
-    // These tests fail on systems whose C library doesn't provide a correct overload
-    // set for wcschr, wcspbrk, wcsrchr, wcsstr, and wmemchr, unless the compiler is
-    // a suitably recent version of Clang.
-#if !defined(__APPLE__) || defined(_LIBCPP_PREFERRED_OVERLOAD)
-    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcschr((const wchar_t*)0, L' ')));
-    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcspbrk((const wchar_t*)0, L"")));
-    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcsrchr((const wchar_t*)0, L' ')));
-    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wcsstr((const wchar_t*)0, L"")));
-    ASSERT_SAME_TYPE(const wchar_t*,     decltype(std::wmemchr((const wchar_t*)0, L' ', s)));
-#endif
-
 #ifndef _LIBCPP_HAS_NO_STDIN
     ASSERT_SAME_TYPE(std::wint_t,        decltype(std::getwchar()));
     ASSERT_SAME_TYPE(int,                decltype(std::vwscanf(L"", va)));
     ASSERT_SAME_TYPE(int,                decltype(std::wscanf(L"")));
 #endif
 
 #ifndef _LIBCPP_HAS_NO_STDOUT
     ASSERT_SAME_TYPE(std::wint_t,        decltype(std::putwchar(L' ')));
     ASSERT_SAME_TYPE(int,                decltype(std::vwprintf(L"", va)));
     ASSERT_SAME_TYPE(int,                decltype(std::wprintf(L"")));
 #endif
 
     return 0;
 }