[libcxx-commits] [libcxx] [libc++][NFC] Move namespace macros into a detail header (PR #193003)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Apr 20 10:59:44 PDT 2026
https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/193003
>From b2db353193f8c9b39e9aaa9c9ae0eb249d4929dd Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Tue, 20 Jan 2026 12:59:12 +0100
Subject: [PATCH] [libc++][NFC] Move namespace macros into a detail header
---
libcxx/include/CMakeLists.txt | 2 +
libcxx/include/__config | 86 +------------------
.../__configuration/diagnostic_suppression.h | 43 ++++++++++
libcxx/include/__configuration/namespace.h | 82 ++++++++++++++++++
libcxx/include/module.modulemap.in | 2 +
5 files changed, 131 insertions(+), 84 deletions(-)
create mode 100644 libcxx/include/__configuration/diagnostic_suppression.h
create mode 100644 libcxx/include/__configuration/namespace.h
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 53165f0336b2d..171d5c6caf0db 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -335,9 +335,11 @@ set(files
__configuration/attributes.h
__configuration/availability.h
__configuration/compiler.h
+ __configuration/diagnostic_suppression.h
__configuration/experimental.h
__configuration/hardening.h
__configuration/language.h
+ __configuration/namespace.h
__configuration/platform.h
__coroutine/coroutine_handle.h
__coroutine/coroutine_traits.h
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 942b0a9dbefa3..6cf9652327236 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -22,9 +22,11 @@
# include <__configuration/attributes.h>
# include <__configuration/availability.h>
# include <__configuration/compiler.h>
+# include <__configuration/diagnostic_suppression.h>
# include <__configuration/experimental.h>
# include <__configuration/hardening.h>
# include <__configuration/language.h>
+# include <__configuration/namespace.h>
# include <__configuration/platform.h>
// The attributes supported by clang are documented at https://clang.llvm.org/docs/AttributeReference.html
@@ -178,90 +180,6 @@ typedef __char32_t char32_t;
# define _LIBCPP_HAS_BLOCKS_RUNTIME 0
# endif
-# ifdef _LIBCPP_COMPILER_CLANG_BASED
-# define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
-# define _LIBCPP_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
-# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(clang diagnostic ignored str))
-# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
-# elif defined(_LIBCPP_COMPILER_GCC)
-# define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
-# define _LIBCPP_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
-# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
-# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(GCC diagnostic ignored str))
-# else
-# define _LIBCPP_DIAGNOSTIC_PUSH
-# define _LIBCPP_DIAGNOSTIC_POP
-# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
-# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
-# endif
-
-// Macros to enter and leave a state where deprecation warnings are suppressed.
-# define _LIBCPP_SUPPRESS_DEPRECATED_PUSH \
- _LIBCPP_DIAGNOSTIC_PUSH _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated") \
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wdeprecated-declarations")
-# define _LIBCPP_SUPPRESS_DEPRECATED_POP _LIBCPP_DIAGNOSTIC_POP
-
-// Clang modules take a significant compile time hit when pushing and popping diagnostics.
-// Since all the headers are marked as system headers unless _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER is defined, we can
-// simply disable this pushing and popping when _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER isn't defined.
-# ifdef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
-# define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS \
- _LIBCPP_DIAGNOSTIC_PUSH \
- _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++11-extensions") \
- _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++14-extensions") \
- _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++17-extensions") \
- _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions") \
- _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++23-extensions") \
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++14-extensions") \
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++17-extensions") \
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions") \
- _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++23-extensions")
-# define _LIBCPP_POP_EXTENSION_DIAGNOSTICS _LIBCPP_DIAGNOSTIC_POP
-# else
-# define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS
-# define _LIBCPP_POP_EXTENSION_DIAGNOSTICS
-# endif
-
-// clang-format off
-
-// The unversioned namespace is used when we want to be ABI compatible with other standard libraries in some way. There
-// are two main categories where that's the case:
-// - Historically, we have made exception types ABI compatible with libstdc++ to allow throwing them between libstdc++
-// and libc++. This is not used anymore for new exception types, since there is no use-case for it anymore.
-// - Types and functions which are used by the compiler are in the unversioned namespace, since the compiler has to know
-// their mangling without the appropriate declaration in some cases.
-// If it's not clear whether using the unversioned namespace is the correct thing to do, it's not. The versioned
-// namespace (_LIBCPP_BEGIN_NAMESPACE_STD) should almost always be used.
-# define _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD \
- _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS namespace _LIBCPP_NAMESPACE_VISIBILITY std {
-
-# define _LIBCPP_END_UNVERSIONED_NAMESPACE_STD } _LIBCPP_POP_EXTENSION_DIAGNOSTICS
-
-# define _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD inline namespace _LIBCPP_ABI_NAMESPACE {
-# define _LIBCPP_END_NAMESPACE_STD } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
-
-// TODO: This should really be in the versioned namespace
-#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD namespace experimental {
-#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
-
-#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
-#define _LIBCPP_END_NAMESPACE_LFTS } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
-
-#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
-#define _LIBCPP_END_NAMESPACE_LFTS_V2 } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
-
-#ifdef _LIBCPP_ABI_NO_FILESYSTEM_INLINE_NAMESPACE
-# define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD namespace filesystem {
-# define _LIBCPP_END_NAMESPACE_FILESYSTEM } _LIBCPP_END_NAMESPACE_STD
-#else
-# define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD \
- inline namespace __fs { namespace filesystem {
-
-# define _LIBCPP_END_NAMESPACE_FILESYSTEM }} _LIBCPP_END_NAMESPACE_STD
-#endif
-
-// clang-format on
-
# if !defined(__SIZEOF_INT128__) || defined(_MSC_VER)
# define _LIBCPP_HAS_INT128 0
# else
diff --git a/libcxx/include/__configuration/diagnostic_suppression.h b/libcxx/include/__configuration/diagnostic_suppression.h
new file mode 100644
index 0000000000000..25d43449a6a77
--- /dev/null
+++ b/libcxx/include/__configuration/diagnostic_suppression.h
@@ -0,0 +1,43 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONFIGURATION_DIAGNOSTIC_SUPPRESSION_H
+#define _LIBCPP___CONFIGURATION_DIAGNOSTIC_SUPPRESSION_H
+
+#include <__config_site>
+#include <__configuration/compiler.h>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+# pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_CLANG_BASED
+# define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("clang diagnostic push")
+# define _LIBCPP_DIAGNOSTIC_POP _Pragma("clang diagnostic pop")
+# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(clang diagnostic ignored str))
+# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
+#elif defined(_LIBCPP_COMPILER_GCC)
+# define _LIBCPP_DIAGNOSTIC_PUSH _Pragma("GCC diagnostic push")
+# define _LIBCPP_DIAGNOSTIC_POP _Pragma("GCC diagnostic pop")
+# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
+# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str) _Pragma(_LIBCPP_TOSTRING(GCC diagnostic ignored str))
+#else
+# define _LIBCPP_DIAGNOSTIC_PUSH
+# define _LIBCPP_DIAGNOSTIC_POP
+# define _LIBCPP_CLANG_DIAGNOSTIC_IGNORED(str)
+# define _LIBCPP_GCC_DIAGNOSTIC_IGNORED(str)
+#endif
+
+// Macros to enter and leave a state where deprecation warnings are suppressed.
+#define _LIBCPP_SUPPRESS_DEPRECATED_PUSH \
+ _LIBCPP_DIAGNOSTIC_PUSH _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wdeprecated") \
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wdeprecated-declarations")
+#define _LIBCPP_SUPPRESS_DEPRECATED_POP _LIBCPP_DIAGNOSTIC_POP
+
+#endif // _LIBCPP___CONFIGURATION_DIAGNOSTIC_SUPPRESSION_H
diff --git a/libcxx/include/__configuration/namespace.h b/libcxx/include/__configuration/namespace.h
new file mode 100644
index 0000000000000..740baad567af7
--- /dev/null
+++ b/libcxx/include/__configuration/namespace.h
@@ -0,0 +1,82 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONFIGURATION_NAMESPACE_H
+#define _LIBCPP___CONFIGURATION_NAMESPACE_H
+
+#include <__config_site>
+#include <__configuration/attributes.h>
+#include <__configuration/diagnostic_suppression.h>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+# pragma GCC system_header
+#endif
+
+// Clang modules take a significant compile time hit when pushing and popping diagnostics.
+// Since all the headers are marked as system headers unless _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER is defined, we can
+// simply disable this pushing and popping when _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER isn't defined.
+#ifdef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+# define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS \
+ _LIBCPP_DIAGNOSTIC_PUSH \
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++11-extensions") \
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++14-extensions") \
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++17-extensions") \
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++20-extensions") \
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wc++23-extensions") \
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++14-extensions") \
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++17-extensions") \
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++20-extensions") \
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Wc++23-extensions")
+# define _LIBCPP_POP_EXTENSION_DIAGNOSTICS _LIBCPP_DIAGNOSTIC_POP
+#else
+# define _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS
+# define _LIBCPP_POP_EXTENSION_DIAGNOSTICS
+#endif
+
+// clang-format off
+
+// The unversioned namespace is used when we want to be ABI compatible with other standard libraries in some way. There
+// are two main categories where that's the case:
+// - Historically, we have made exception types ABI compatible with libstdc++ to allow throwing them between libstdc++
+// and libc++. This is not used anymore for new exception types, since there is no use-case for it anymore.
+// - Types and functions which are used by the compiler are in the unversioned namespace, since the compiler has to know
+// their mangling without the appropriate declaration in some cases.
+// If it's not clear whether using the unversioned namespace is the correct thing to do, it's not. The versioned
+// namespace (_LIBCPP_BEGIN_NAMESPACE_STD) should almost always be used.
+# define _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD \
+ _LIBCPP_PUSH_EXTENSION_DIAGNOSTICS namespace _LIBCPP_NAMESPACE_VISIBILITY std {
+
+# define _LIBCPP_END_UNVERSIONED_NAMESPACE_STD } _LIBCPP_POP_EXTENSION_DIAGNOSTICS
+
+# define _LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD inline namespace _LIBCPP_ABI_NAMESPACE {
+# define _LIBCPP_END_NAMESPACE_STD } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
+
+// TODO: This should really be in the versioned namespace
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL _LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD namespace experimental {
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL } _LIBCPP_END_UNVERSIONED_NAMESPACE_STD
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
+#define _LIBCPP_END_NAMESPACE_LFTS } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
+#define _LIBCPP_END_NAMESPACE_LFTS_V2 } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#ifdef _LIBCPP_ABI_NO_FILESYSTEM_INLINE_NAMESPACE
+# define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD namespace filesystem {
+# define _LIBCPP_END_NAMESPACE_FILESYSTEM } _LIBCPP_END_NAMESPACE_STD
+#else
+# define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM _LIBCPP_BEGIN_NAMESPACE_STD \
+ inline namespace __fs { namespace filesystem {
+
+# define _LIBCPP_END_NAMESPACE_FILESYSTEM }} _LIBCPP_END_NAMESPACE_STD
+#endif
+
+// clang-format on
+
+#endif // _LIBCPP___CONFIGURATION_NAMESPACE_H
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index d6e8289b7c8b0..3f0c241fbe20a 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -7,9 +7,11 @@ module std_config [system] {
textual header "__configuration/attributes.h"
textual header "__configuration/availability.h"
textual header "__configuration/compiler.h"
+ textual header "__configuration/diagnostic_suppression.h"
textual header "__configuration/experimental.h"
textual header "__configuration/hardening.h"
textual header "__configuration/language.h"
+ textual header "__configuration/namespace.h"
textual header "__configuration/platform.h"
textual header "version"
}
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