[libcxx-commits] [libcxx] [libcxx] Define _LIBCPP_HAS_C8RTOMB_MBRTOC8 for picolibc (PR #158648)
Victor Campos via libcxx-commits
libcxx-commits at lists.llvm.org
Fri Sep 19 03:09:29 PDT 2025
https://github.com/vhscampos updated https://github.com/llvm/llvm-project/pull/158648
>From 656fce279583db9f2fb9a2f89d3a76937d1887df Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Thu, 7 Aug 2025 16:03:44 +0100
Subject: [PATCH 1/3] [libcxx] Define _LIBCPP_HAS_C8RTOMB_MBRTOC8 for picolibc
Starting from picolibc 1.8.9, the `char8_t` related functions are
provided.
This patch adds logic to detect the underlying picolibc version and
define the `_LIBCPP_HAS_C8RTOMB_MBRTOC8 macro` accordingly.
---
libcxx/include/__config | 4 ++-
.../depr.c.headers/uchar_h.compile.pass.cpp | 5 ----
.../uchar_h_char8_t.compile.pass.cpp | 27 +++++++++++++++++
.../strings/c.strings/cuchar.compile.pass.cpp | 5 ----
.../c.strings/cuchar_char8_t.compile.pass.cpp | 27 +++++++++++++++++
.../c.strings/no_c8rtomb_mbrtoc8.verify.cpp | 30 -------------------
6 files changed, 57 insertions(+), 41 deletions(-)
create mode 100644 libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
create mode 100644 libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
delete mode 100644 libcxx/test/std/strings/c.strings/no_c8rtomb_mbrtoc8.verify.cpp
diff --git a/libcxx/include/__config b/libcxx/include/__config
index b4c081dcdff1b..5971a3c5407b9 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1021,7 +1021,9 @@ typedef __char32_t char32_t;
// the latter depends on internal GNU libc details that are not appropriate
// to depend on here, so any declarations present when __cpp_char8_t is not
// defined are ignored.
-# if defined(_LIBCPP_GLIBC_PREREQ)
+# if defined(__clang__)
+# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
+# elif defined(_LIBCPP_GLIBC_PREREQ)
# if _LIBCPP_GLIBC_PREREQ(2, 36) && defined(__cpp_char8_t)
# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
# else
diff --git a/libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp b/libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp
index a1560c8ee5853..c448ba83f4b38 100644
--- a/libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/uchar_h.compile.pass.cpp
@@ -23,11 +23,6 @@
// __STDC_UTF_16__ may or may not be defined by the C standard library
// __STDC_UTF_32__ may or may not be defined by the C standard library
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
-ASSERT_SAME_TYPE(size_t, decltype(mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
-ASSERT_SAME_TYPE(size_t, decltype(c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
-
ASSERT_SAME_TYPE(size_t, decltype(mbrtoc16((char16_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
ASSERT_SAME_TYPE(size_t, decltype(c16rtomb((char*)0, (char16_t)0, (mbstate_t*)0)));
diff --git a/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp b/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
new file mode 100644
index 0000000000000..1c204cbc3f68f
--- /dev/null
+++ b/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// 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++03
+
+// The following platforms do not provide mbrtoc8 and c8rtomb so the tests fail
+// XFAIL: target={{.+}}-aix{{.*}}
+// XFAIL: darwin
+// XFAIL: freebsd
+// XFAIL: windows
+// XFAIL: LIBCXX-PICOLIBC-FIXME
+
+// <uchar.h>
+
+#include <uchar.h>
+
+#include "test_macros.h"
+
+#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
+ASSERT_SAME_TYPE(size_t, decltype(mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
+ASSERT_SAME_TYPE(size_t, decltype(c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
+#endif
diff --git a/libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp b/libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp
index 2076384deb2b2..96b394a9934f8 100644
--- a/libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cuchar.compile.pass.cpp
@@ -23,11 +23,6 @@
// __STDC_UTF_16__ may or may not be defined by the C standard library
// __STDC_UTF_32__ may or may not be defined by the C standard library
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
-ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
-ASSERT_SAME_TYPE(std::size_t, decltype(std::c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
-
ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc16((char16_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
ASSERT_SAME_TYPE(std::size_t, decltype(std::c16rtomb((char*)0, (char16_t)0, (mbstate_t*)0)));
diff --git a/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp b/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
new file mode 100644
index 0000000000000..b0694c2100524
--- /dev/null
+++ b/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// 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++03
+
+// The following platforms do not provide mbrtoc8 and c8rtomb so the tests fail
+// XFAIL: target={{.+}}-aix{{.*}}
+// XFAIL: darwin
+// XFAIL: freebsd
+// XFAIL: windows
+// XFAIL: LIBCXX-PICOLIBC-FIXME
+
+// <cuchar>
+
+#include <cuchar>
+
+#include "test_macros.h"
+
+#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
+ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
+ASSERT_SAME_TYPE(std::size_t, decltype(std::c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
+#endif
diff --git a/libcxx/test/std/strings/c.strings/no_c8rtomb_mbrtoc8.verify.cpp b/libcxx/test/std/strings/c.strings/no_c8rtomb_mbrtoc8.verify.cpp
deleted file mode 100644
index 1d4a225668d80..0000000000000
--- a/libcxx/test/std/strings/c.strings/no_c8rtomb_mbrtoc8.verify.cpp
+++ /dev/null
@@ -1,30 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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++03
-
-#include <uchar.h>
-
-#include "test_macros.h"
-
-// When C++ char8_t support is not enabled, definitions of these functions that
-// match the C2X declarations may still be present in the global namespace with
-// a char8_t typedef substituted for the C++ char8_t type. If so, these are not
-// the declarations we are looking for, so don't test for them.
-#if !defined(TEST_HAS_NO_CHAR8_T)
-using U = decltype(::c8rtomb);
-using V = decltype(::mbrtoc8);
-# if !_LIBCPP_HAS_C8RTOMB_MBRTOC8
-// expected-error at -3 {{no member named 'c8rtomb' in the global namespace}}
-// expected-error at -3 {{no member named 'mbrtoc8' in the global namespace}}
-# else
-// expected-no-diagnostics
-# endif
-#else
-// expected-no-diagnostics
-#endif
>From 91a2fcf6dede49c891a1ea2a6424186095586393 Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Thu, 18 Sep 2025 14:51:16 +0100
Subject: [PATCH 2/3] Change if-else order
---
libcxx/include/__config | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 5971a3c5407b9..45f6852e379a7 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1021,14 +1021,14 @@ typedef __char32_t char32_t;
// the latter depends on internal GNU libc details that are not appropriate
// to depend on here, so any declarations present when __cpp_char8_t is not
// defined are ignored.
-# if defined(__clang__)
-# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
-# elif defined(_LIBCPP_GLIBC_PREREQ)
+# if defined(_LIBCPP_GLIBC_PREREQ)
# if _LIBCPP_GLIBC_PREREQ(2, 36) && defined(__cpp_char8_t)
# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
# else
# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
# endif
+# elif defined(__clang__)
+# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 1
# else
# define _LIBCPP_HAS_C8RTOMB_MBRTOC8 0
# endif
>From ea9d9802305f7b027f3422df8cff1176b52add2e Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Fri, 19 Sep 2025 11:03:06 +0100
Subject: [PATCH 3/3] Try and remove testing macro use
---
.../std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp | 4 ----
.../std/strings/c.strings/cuchar_char8_t.compile.pass.cpp | 4 ----
2 files changed, 8 deletions(-)
diff --git a/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp b/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
index 1c204cbc3f68f..91e92ccb727a7 100644
--- a/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
+++ b/libcxx/test/std/depr/depr.c.headers/uchar_h_char8_t.compile.pass.cpp
@@ -19,9 +19,5 @@
#include <uchar.h>
-#include "test_macros.h"
-
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
ASSERT_SAME_TYPE(size_t, decltype(mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
ASSERT_SAME_TYPE(size_t, decltype(c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
diff --git a/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp b/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
index b0694c2100524..0d07bcdd1a9a7 100644
--- a/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
+++ b/libcxx/test/std/strings/c.strings/cuchar_char8_t.compile.pass.cpp
@@ -19,9 +19,5 @@
#include <cuchar>
-#include "test_macros.h"
-
-#if !defined(TEST_HAS_NO_C8RTOMB_MBRTOC8)
ASSERT_SAME_TYPE(std::size_t, decltype(std::mbrtoc8((char8_t*)0, (const char*)0, (size_t)0, (mbstate_t*)0)));
ASSERT_SAME_TYPE(std::size_t, decltype(std::c8rtomb((char*)0, (char8_t)0, (mbstate_t*)0)));
-#endif
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