[libcxx-commits] [libcxx] [libc++] Split __shared_count out of <__memory/shared_ptr.h> (PR #115943)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Wed Nov 13 01:26:54 PST 2024
https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/115943
>From 438765744bb511f97d34727f5404eca6e0320ba4 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Tue, 12 Nov 2024 22:41:15 +0100
Subject: [PATCH] [libc++] Split __shared_count out of <__memory/shared_ptr.h>
---
libcxx/include/CMakeLists.txt | 1 +
libcxx/include/__locale | 2 +-
libcxx/include/__memory/shared_count.h | 136 +++++++++++++++++++++++++
libcxx/include/__memory/shared_ptr.h | 114 +--------------------
libcxx/include/__mutex/once_flag.h | 2 +-
libcxx/include/future | 2 +-
libcxx/include/module.modulemap | 1 +
libcxx/include/mutex | 1 -
8 files changed, 142 insertions(+), 117 deletions(-)
create mode 100644 libcxx/include/__memory/shared_count.h
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index dd774b25a81eda..1610d1ee848a5f 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -557,6 +557,7 @@ set(files
__memory/ranges_construct_at.h
__memory/ranges_uninitialized_algorithms.h
__memory/raw_storage_iterator.h
+ __memory/shared_count.h
__memory/shared_ptr.h
__memory/swap_allocator.h
__memory/temp_value.h
diff --git a/libcxx/include/__locale b/libcxx/include/__locale
index b07b9f3329f42c..b675e01bac81e5 100644
--- a/libcxx/include/__locale
+++ b/libcxx/include/__locale
@@ -12,7 +12,7 @@
#include <__config>
#include <__locale_dir/locale_base_api.h>
-#include <__memory/shared_ptr.h> // __shared_count
+#include <__memory/shared_count.h>
#include <__mutex/once_flag.h>
#include <__type_traits/make_unsigned.h>
#include <__utility/no_destroy.h>
diff --git a/libcxx/include/__memory/shared_count.h b/libcxx/include/__memory/shared_count.h
new file mode 100644
index 00000000000000..1438c6ba5a6d29
--- /dev/null
+++ b/libcxx/include/__memory/shared_count.h
@@ -0,0 +1,136 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___MEMORY_SHARED_COUNT_H
+#define _LIBCPP___MEMORY_SHARED_COUNT_H
+
+#include <__config>
+#include <typeinfo>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively)
+// should be sufficient for thread safety.
+// See https://llvm.org/PR22803
+#if (defined(__clang__) && __has_builtin(__atomic_add_fetch) && defined(__ATOMIC_RELAXED) && \
+ defined(__ATOMIC_ACQ_REL)) || \
+ defined(_LIBCPP_COMPILER_GCC)
+# define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT 1
+#else
+# define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT 0
+#endif
+
+template <class _ValueType>
+inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_relaxed_load(_ValueType const* __value) {
+#if _LIBCPP_HAS_THREADS && defined(__ATOMIC_RELAXED) && \
+ (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
+ return __atomic_load_n(__value, __ATOMIC_RELAXED);
+#else
+ return *__value;
+#endif
+}
+
+template <class _ValueType>
+inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_acquire_load(_ValueType const* __value) {
+#if _LIBCPP_HAS_THREADS && defined(__ATOMIC_ACQUIRE) && \
+ (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
+ return __atomic_load_n(__value, __ATOMIC_ACQUIRE);
+#else
+ return *__value;
+#endif
+}
+
+template <class _Tp>
+inline _LIBCPP_HIDE_FROM_ABI _Tp __libcpp_atomic_refcount_increment(_Tp& __t) _NOEXCEPT {
+#if _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT && _LIBCPP_HAS_THREADS
+ return __atomic_add_fetch(&__t, 1, __ATOMIC_RELAXED);
+#else
+ return __t += 1;
+#endif
+}
+
+template <class _Tp>
+inline _LIBCPP_HIDE_FROM_ABI _Tp __libcpp_atomic_refcount_decrement(_Tp& __t) _NOEXCEPT {
+#if _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT && _LIBCPP_HAS_THREADS
+ return __atomic_add_fetch(&__t, -1, __ATOMIC_ACQ_REL);
+#else
+ return __t -= 1;
+#endif
+}
+
+class _LIBCPP_EXPORTED_FROM_ABI __shared_count {
+ __shared_count(const __shared_count&);
+ __shared_count& operator=(const __shared_count&);
+
+protected:
+ long __shared_owners_;
+ virtual ~__shared_count();
+
+private:
+ virtual void __on_zero_shared() _NOEXCEPT = 0;
+
+public:
+ _LIBCPP_HIDE_FROM_ABI explicit __shared_count(long __refs = 0) _NOEXCEPT : __shared_owners_(__refs) {}
+
+#if defined(_LIBCPP_SHARED_PTR_DEFINE_LEGACY_INLINE_FUNCTIONS)
+ void __add_shared() noexcept;
+ bool __release_shared() noexcept;
+#else
+ _LIBCPP_HIDE_FROM_ABI void __add_shared() _NOEXCEPT { __libcpp_atomic_refcount_increment(__shared_owners_); }
+ _LIBCPP_HIDE_FROM_ABI bool __release_shared() _NOEXCEPT {
+ if (__libcpp_atomic_refcount_decrement(__shared_owners_) == -1) {
+ __on_zero_shared();
+ return true;
+ }
+ return false;
+ }
+#endif
+ _LIBCPP_HIDE_FROM_ABI long use_count() const _NOEXCEPT { return __libcpp_relaxed_load(&__shared_owners_) + 1; }
+};
+
+class _LIBCPP_EXPORTED_FROM_ABI __shared_weak_count : private __shared_count {
+ long __shared_weak_owners_;
+
+public:
+ _LIBCPP_HIDE_FROM_ABI explicit __shared_weak_count(long __refs = 0) _NOEXCEPT
+ : __shared_count(__refs),
+ __shared_weak_owners_(__refs) {}
+
+protected:
+ ~__shared_weak_count() override;
+
+public:
+#if defined(_LIBCPP_SHARED_PTR_DEFINE_LEGACY_INLINE_FUNCTIONS)
+ void __add_shared() noexcept;
+ void __add_weak() noexcept;
+ void __release_shared() noexcept;
+#else
+ _LIBCPP_HIDE_FROM_ABI void __add_shared() _NOEXCEPT { __shared_count::__add_shared(); }
+ _LIBCPP_HIDE_FROM_ABI void __add_weak() _NOEXCEPT { __libcpp_atomic_refcount_increment(__shared_weak_owners_); }
+ _LIBCPP_HIDE_FROM_ABI void __release_shared() _NOEXCEPT {
+ if (__shared_count::__release_shared())
+ __release_weak();
+ }
+#endif
+ void __release_weak() _NOEXCEPT;
+ _LIBCPP_HIDE_FROM_ABI long use_count() const _NOEXCEPT { return __shared_count::use_count(); }
+ __shared_weak_count* lock() _NOEXCEPT;
+
+ virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;
+
+private:
+ virtual void __on_zero_shared_weak() _NOEXCEPT = 0;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_SHARED_COUNT_H
diff --git a/libcxx/include/__memory/shared_ptr.h b/libcxx/include/__memory/shared_ptr.h
index 5a84c2ce9bfe17..5c34f2efc5730e 100644
--- a/libcxx/include/__memory/shared_ptr.h
+++ b/libcxx/include/__memory/shared_ptr.h
@@ -30,6 +30,7 @@
#include <__memory/compressed_pair.h>
#include <__memory/construct_at.h>
#include <__memory/pointer_traits.h>
+#include <__memory/shared_count.h>
#include <__memory/uninitialized_algorithms.h>
#include <__memory/unique_ptr.h>
#include <__type_traits/add_lvalue_reference.h>
@@ -70,55 +71,6 @@ _LIBCPP_PUSH_MACROS
_LIBCPP_BEGIN_NAMESPACE_STD
-// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively)
-// should be sufficient for thread safety.
-// See https://llvm.org/PR22803
-#if (defined(__clang__) && __has_builtin(__atomic_add_fetch) && defined(__ATOMIC_RELAXED) && \
- defined(__ATOMIC_ACQ_REL)) || \
- defined(_LIBCPP_COMPILER_GCC)
-# define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT 1
-#else
-# define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT 0
-#endif
-
-template <class _ValueType>
-inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_relaxed_load(_ValueType const* __value) {
-#if _LIBCPP_HAS_THREADS && defined(__ATOMIC_RELAXED) && \
- (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
- return __atomic_load_n(__value, __ATOMIC_RELAXED);
-#else
- return *__value;
-#endif
-}
-
-template <class _ValueType>
-inline _LIBCPP_HIDE_FROM_ABI _ValueType __libcpp_acquire_load(_ValueType const* __value) {
-#if _LIBCPP_HAS_THREADS && defined(__ATOMIC_ACQUIRE) && \
- (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
- return __atomic_load_n(__value, __ATOMIC_ACQUIRE);
-#else
- return *__value;
-#endif
-}
-
-template <class _Tp>
-inline _LIBCPP_HIDE_FROM_ABI _Tp __libcpp_atomic_refcount_increment(_Tp& __t) _NOEXCEPT {
-#if _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT && _LIBCPP_HAS_THREADS
- return __atomic_add_fetch(&__t, 1, __ATOMIC_RELAXED);
-#else
- return __t += 1;
-#endif
-}
-
-template <class _Tp>
-inline _LIBCPP_HIDE_FROM_ABI _Tp __libcpp_atomic_refcount_decrement(_Tp& __t) _NOEXCEPT {
-#if _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT && _LIBCPP_HAS_THREADS
- return __atomic_add_fetch(&__t, -1, __ATOMIC_ACQ_REL);
-#else
- return __t -= 1;
-#endif
-}
-
class _LIBCPP_EXPORTED_FROM_ABI bad_weak_ptr : public std::exception {
public:
_LIBCPP_HIDE_FROM_ABI bad_weak_ptr() _NOEXCEPT = default;
@@ -139,70 +91,6 @@ class _LIBCPP_EXPORTED_FROM_ABI bad_weak_ptr : public std::exception {
template <class _Tp>
class _LIBCPP_TEMPLATE_VIS weak_ptr;
-class _LIBCPP_EXPORTED_FROM_ABI __shared_count {
- __shared_count(const __shared_count&);
- __shared_count& operator=(const __shared_count&);
-
-protected:
- long __shared_owners_;
- virtual ~__shared_count();
-
-private:
- virtual void __on_zero_shared() _NOEXCEPT = 0;
-
-public:
- _LIBCPP_HIDE_FROM_ABI explicit __shared_count(long __refs = 0) _NOEXCEPT : __shared_owners_(__refs) {}
-
-#if defined(_LIBCPP_SHARED_PTR_DEFINE_LEGACY_INLINE_FUNCTIONS)
- void __add_shared() noexcept;
- bool __release_shared() noexcept;
-#else
- _LIBCPP_HIDE_FROM_ABI void __add_shared() _NOEXCEPT { __libcpp_atomic_refcount_increment(__shared_owners_); }
- _LIBCPP_HIDE_FROM_ABI bool __release_shared() _NOEXCEPT {
- if (__libcpp_atomic_refcount_decrement(__shared_owners_) == -1) {
- __on_zero_shared();
- return true;
- }
- return false;
- }
-#endif
- _LIBCPP_HIDE_FROM_ABI long use_count() const _NOEXCEPT { return __libcpp_relaxed_load(&__shared_owners_) + 1; }
-};
-
-class _LIBCPP_EXPORTED_FROM_ABI __shared_weak_count : private __shared_count {
- long __shared_weak_owners_;
-
-public:
- _LIBCPP_HIDE_FROM_ABI explicit __shared_weak_count(long __refs = 0) _NOEXCEPT
- : __shared_count(__refs),
- __shared_weak_owners_(__refs) {}
-
-protected:
- ~__shared_weak_count() override;
-
-public:
-#if defined(_LIBCPP_SHARED_PTR_DEFINE_LEGACY_INLINE_FUNCTIONS)
- void __add_shared() noexcept;
- void __add_weak() noexcept;
- void __release_shared() noexcept;
-#else
- _LIBCPP_HIDE_FROM_ABI void __add_shared() _NOEXCEPT { __shared_count::__add_shared(); }
- _LIBCPP_HIDE_FROM_ABI void __add_weak() _NOEXCEPT { __libcpp_atomic_refcount_increment(__shared_weak_owners_); }
- _LIBCPP_HIDE_FROM_ABI void __release_shared() _NOEXCEPT {
- if (__shared_count::__release_shared())
- __release_weak();
- }
-#endif
- void __release_weak() _NOEXCEPT;
- _LIBCPP_HIDE_FROM_ABI long use_count() const _NOEXCEPT { return __shared_count::use_count(); }
- __shared_weak_count* lock() _NOEXCEPT;
-
- virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;
-
-private:
- virtual void __on_zero_shared_weak() _NOEXCEPT = 0;
-};
-
template <class _Tp, class _Dp, class _Alloc>
class __shared_ptr_pointer : public __shared_weak_count {
_LIBCPP_COMPRESSED_TRIPLE(_Tp, __ptr_, _Dp, __deleter_, _Alloc, __alloc_);
diff --git a/libcxx/include/__mutex/once_flag.h b/libcxx/include/__mutex/once_flag.h
index 9d7baecbc70859..08ff54bf99265e 100644
--- a/libcxx/include/__mutex/once_flag.h
+++ b/libcxx/include/__mutex/once_flag.h
@@ -11,7 +11,7 @@
#include <__config>
#include <__functional/invoke.h>
-#include <__memory/shared_ptr.h> // __libcpp_acquire_load
+#include <__memory/shared_count.h> // __libcpp_acquire_load
#include <__tuple/tuple_indices.h>
#include <__tuple/tuple_size.h>
#include <__utility/forward.h>
diff --git a/libcxx/include/future b/libcxx/include/future
index 67d9b43ff22e32..9f7c95e542fd60 100644
--- a/libcxx/include/future
+++ b/libcxx/include/future
@@ -378,7 +378,7 @@ template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
# include <__memory/allocator_traits.h>
# include <__memory/compressed_pair.h>
# include <__memory/pointer_traits.h>
-# include <__memory/shared_ptr.h>
+# include <__memory/shared_count.h>
# include <__memory/unique_ptr.h>
# include <__memory/uses_allocator.h>
# include <__system_error/error_category.h>
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index 9027c28632dcda..cd08b2810e437b 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -1542,6 +1542,7 @@ module std [system] {
export std.algorithm.in_out_result
}
module raw_storage_iterator { header "__memory/raw_storage_iterator.h" }
+ module shared_count { header "__memory/shared_count.h" }
module shared_ptr { header "__memory/shared_ptr.h" }
module swap_allocator { header "__memory/swap_allocator.h" }
module temp_value { header "__memory/temp_value.h" }
diff --git a/libcxx/include/mutex b/libcxx/include/mutex
index 60a7c9945909ce..ecbfc5607dcc78 100644
--- a/libcxx/include/mutex
+++ b/libcxx/include/mutex
@@ -190,7 +190,6 @@ template<class Callable, class ...Args>
#include <__chrono/time_point.h>
#include <__condition_variable/condition_variable.h>
#include <__config>
-#include <__memory/shared_ptr.h>
#include <__mutex/lock_guard.h>
#include <__mutex/mutex.h>
#include <__mutex/once_flag.h>
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