[libcxx-commits] [libcxx] [libc++] Define __shared_mutex_base's destructor in the dylib (PR #148047)
Louis Dionne via libcxx-commits
libcxx-commits at lists.llvm.org
Thu Jul 10 12:53:48 PDT 2025
https://github.com/ldionne created https://github.com/llvm/llvm-project/pull/148047
This makes the whole implementation of __shared_mutex_base live in the dylib, which means that we could in principle change its implementation without introducing an ABI break, once we are comfortable with assuming that no code out there remains with the inline destructor implementation.
>From 8b1950a9a83bd1838b7461d5f12de93641db0ccc Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2 at gmail.com>
Date: Thu, 10 Jul 2025 13:32:41 -0400
Subject: [PATCH] [libc++] Define __shared_mutex_base's destructor in the dylib
This makes the whole implementation of __shared_mutex_base live in the
dylib, which means that we could in principle change its implementation
without introducing an ABI break, once we are comfortable with assuming
that no code out there remains with the inline destructor implementation.
---
libcxx/include/__configuration/availability.h | 6 ++++++
libcxx/include/shared_mutex | 4 ++++
...pple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...x-android21.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...rpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...c64-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...pple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...x-android21.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...own-freebsd.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...n-linux-gnu.libcxxabi.v1.stable.exceptions.nonew.abilist | 2 ++
...linux-gnu.libcxxabi.v1.stable.noexceptions.nonew.abilist | 2 ++
libcxx/src/shared_mutex.cpp | 1 +
12 files changed, 29 insertions(+)
diff --git a/libcxx/include/__configuration/availability.h b/libcxx/include/__configuration/availability.h
index ae58e36b508b44..19dce7d9c8c8ea 100644
--- a/libcxx/include/__configuration/availability.h
+++ b/libcxx/include/__configuration/availability.h
@@ -355,6 +355,12 @@
#define _LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE _LIBCPP_INTRODUCED_IN_LLVM_21
// No attribute, since we've had bad_function_call::what() in the headers before
+// This controls whether we assume that __shared_mutex_base::~__shared_mutex_base() is defined in the dylib.
+// Defining that function in the dylib provides additional flexibility for changing the representation of the
+// class, which may eventually be used to provide a better implementation.
+#define _LIBCPP_AVAILABILITY_HAS_SHARED_MUTEX_BASE_DESTRUCTOR _LIBCPP_INTRODUCED_IN_LLVM_21
+// No attribute, since we define the destructor in the headers otherwise
+
// Define availability attributes that depend on both
// _LIBCPP_HAS_EXCEPTIONS and _LIBCPP_HAS_RTTI.
#if !_LIBCPP_HAS_EXCEPTIONS || !_LIBCPP_HAS_RTTI
diff --git a/libcxx/include/shared_mutex b/libcxx/include/shared_mutex
index 8c02e348e4de75..f8836d46e9a43c 100644
--- a/libcxx/include/shared_mutex
+++ b/libcxx/include/shared_mutex
@@ -163,7 +163,11 @@ struct _LIBCPP_EXPORTED_FROM_ABI __shared_mutex_base {
static const unsigned __n_readers_ = ~__write_entered_;
__shared_mutex_base();
+# if defined(_LIBCPP_BUILDING_LIBRARY) || _LIBCPP_AVAILABILITY_HAS_SHARED_MUTEX_BASE_DESTRUCTOR
+ ~__shared_mutex_base();
+# else
_LIBCPP_HIDE_FROM_ABI ~__shared_mutex_base() = default;
+# endif
__shared_mutex_base(const __shared_mutex_base&) = delete;
__shared_mutex_base& operator=(const __shared_mutex_base&) = delete;
diff --git a/libcxx/lib/abi/arm64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/arm64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
index 162757c7e37eca..b14921aebfe499 100644
--- a/libcxx/lib/abi/arm64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/arm64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1551,6 +1551,8 @@
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/i686-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/i686-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
index 4b6f3548ce4958..189314de51ffc0 100644
--- a/libcxx/lib/abi/i686-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/i686-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1187,6 +1187,8 @@
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/powerpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/powerpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
index 2b85596bd87f6d..cd589017794332 100644
--- a/libcxx/lib/abi/powerpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/powerpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -545,6 +545,8 @@
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_base8try_lockEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC1Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC2Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD1Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD2Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count14__release_weakEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count4lockEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_countD0Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/powerpc64-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/powerpc64-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
index 6ebdab96ed4559..f55df888a0a299 100644
--- a/libcxx/lib/abi/powerpc64-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/powerpc64-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -545,6 +545,8 @@
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_base8try_lockEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC1Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC2Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD1Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD2Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count14__release_weakEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count4lockEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNSt3__119__shared_weak_countD0Ev', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/x86_64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/x86_64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
index f6f7d7fd8265ab..38221d575eea0a 100644
--- a/libcxx/lib/abi/x86_64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/x86_64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1550,6 +1550,8 @@
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '__ZNSt3__119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '__ZNSt3__119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/x86_64-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/x86_64-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
index 45f3d7c5904e85..a7106d91023851 100644
--- a/libcxx/lib/abi/x86_64-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/x86_64-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1187,6 +1187,8 @@
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt6__ndk119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/x86_64-unknown-freebsd.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/x86_64-unknown-freebsd.libcxxabi.v1.stable.exceptions.nonew.abilist
index de8cf6deef1dff..88acfbda37c6df 100644
--- a/libcxx/lib/abi/x86_64-unknown-freebsd.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/x86_64-unknown-freebsd.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1201,6 +1201,8 @@
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.exceptions.nonew.abilist b/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.exceptions.nonew.abilist
index 8c55c4385f6f6c..30618108ee8b73 100644
--- a/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.exceptions.nonew.abilist
+++ b/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.exceptions.nonew.abilist
@@ -1199,6 +1199,8 @@
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.noexceptions.nonew.abilist b/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.noexceptions.nonew.abilist
index 51caa07a74330b..58d4ed765ab920 100644
--- a/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.noexceptions.nonew.abilist
+++ b/libcxx/lib/abi/x86_64-unknown-linux-gnu.libcxxabi.v1.stable.noexceptions.nonew.abilist
@@ -1170,6 +1170,8 @@
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_base8try_lockEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC1Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseC2Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD1Ev', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNSt3__119__shared_mutex_baseD2Ev', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count10__add_weakEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count12__add_sharedEv', 'type': 'FUNC'}
{'is_defined': True, 'name': '_ZNSt3__119__shared_weak_count14__release_weakEv', 'type': 'FUNC'}
diff --git a/libcxx/src/shared_mutex.cpp b/libcxx/src/shared_mutex.cpp
index 61808337369561..27ef9d351966dd 100644
--- a/libcxx/src/shared_mutex.cpp
+++ b/libcxx/src/shared_mutex.cpp
@@ -16,6 +16,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
// Shared Mutex Base
__shared_mutex_base::__shared_mutex_base() : __state_(0) {}
+__shared_mutex_base::~__shared_mutex_base() {}
// Exclusive ownership
More information about the libcxx-commits
mailing list