[libc++] Use availability to rely on key functions for bad_expected_access and bad_function_call

libcxx/include/__availability

@@ -160,6 +160,15 @@
 #  define _LIBCPP_AVAILABILITY_HAS_TZDB 1
 #  define _LIBCPP_AVAILABILITY_TZDB
 
+// These macros determine whether we assume that std::bad_function_call and
+// std::bad_expected_access provide a key function in the dylib. This allows
+// centralizing their vtable and typeinfo instead of having all TUs provide
+// a weak definition that then gets deduplicated.
+#  define _LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_KEY_FUNCTION 1
+#  define _LIBCPP_AVAILABILITY_BAD_FUNCTION_CALL_KEY_FUNCTION
+#  define _LIBCPP_AVAILABILITY_HAS_BAD_EXPECTED_ACCESS_KEY_FUNCTION 1
+#  define _LIBCPP_AVAILABILITY_BAD_EXPECTED_ACCESS_KEY_FUNCTION
+
 #elif defined(__APPLE__)
 
 #  define _LIBCPP_AVAILABILITY_HAS_BAD_OPTIONAL_ACCESS                                                                 \
@@ -290,6 +299,13 @@
 #  else
 #    define _LIBCPP_AVAILABILITY_HAS_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1 1
 #  endif
+
+#  define _LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_KEY_FUNCTION 0
+#  define _LIBCPP_AVAILABILITY_BAD_FUNCTION_CALL_KEY_FUNCTION __attribute__((unavailable))
+
+#  define _LIBCPP_AVAILABILITY_HAS_BAD_EXPECTED_ACCESS_KEY_FUNCTION 0
+#  define _LIBCPP_AVAILABILITY_BAD_EXPECTED_ACCESS_KEY_FUNCTION __attribute__((unavailable))
+
 #else
 
 // ...New vendors can add availability markup here...

libcxx/include/__config

@@ -120,14 +120,11 @@
 #    define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
 #    define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
 #    define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
-// Define a key function for `bad_function_call` in the library, to centralize
-// its vtable and typeinfo to libc++ rather than having all other libraries
-// using that class define their own copies.
-#    define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
-// Override the default return value of exception::what() for
-// bad_function_call::what() with a string that is specific to
-// bad_function_call (see http://wg21.link/LWG2233). This is an ABI break
-// because it changes the vtable layout of bad_function_call.
+// Override the default return value of exception::what() for bad_function_call::what()
+// with a string that is specific to bad_function_call (see http://wg21.link/LWG2233).
+// This is an ABI break on platforms that sign and authenticate vtable function pointers
+// because it changes the mangling of the virtual function located in the vtable, which
+// changes how it gets signed.
 #    define _LIBCPP_ABI_BAD_FUNCTION_CALL_GOOD_WHAT_MESSAGE
 // Enable optimized version of __do_get_(un)signed which avoids redundant copies.
 #    define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
@@ -197,19 +194,6 @@
 #    if defined(__FreeBSD__) && __FreeBSD__ < 14
 #      define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
 #    endif
-// For XCOFF linkers, we have problems if we see a weak hidden version of a symbol
-// in user code (like you get with -fvisibility-inlines-hidden) and then a strong def
-// in the library, so we need to always rely on the library version.
-#    if defined(_AIX)
-#      define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
-#    endif
-#  endif
-
-#  if defined(_LIBCPP_BUILDING_LIBRARY) || _LIBCPP_ABI_VERSION >= 2
-// Define a key function for `bad_function_call` in the library, to centralize
-// its vtable and typeinfo to libc++ rather than having all other libraries
-// using that class define their own copies.
-#    define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
 #  endif
 
 // We had some bugs where we use [[no_unique_address]] together with construct_at,

libcxx/include/__expected/bad_expected_access.h

@@ -9,6 +9,7 @@
 #ifndef _LIBCPP___EXPECTED_BAD_EXPECTED_ACCESS_H
 #define _LIBCPP___EXPECTED_BAD_EXPECTED_ACCESS_H
 
+#include <__availability>
 #include <__config>
 #include <__exception/exception.h>
 #include <__utility/move.h>
@@ -28,9 +29,11 @@ template <class _Err>
 class bad_expected_access;
 
 _LIBCPP_DIAGNOSTIC_PUSH
+#  if !_LIBCPP_AVAILABILITY_HAS_BAD_EXPECTED_ACCESS_KEY_FUNCTION
 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wweak-vtables")
+#  endif
 template <>
-class bad_expected_access<void> : public exception {
+class _LIBCPP_EXPORTED_FROM_ABI bad_expected_access<void> : public exception {
 protected:
   _LIBCPP_HIDE_FROM_ABI bad_expected_access() noexcept                             = default;
   _LIBCPP_HIDE_FROM_ABI bad_expected_access(const bad_expected_access&)            = default;
@@ -40,11 +43,11 @@ class bad_expected_access<void> : public exception {
   _LIBCPP_HIDE_FROM_ABI_VIRTUAL ~bad_expected_access() override                    = default;
 
 public:
-  // The way this has been designed (by using a class template below) means that we'll already
-  // have a profusion of these vtables in TUs, and the dynamic linker will already have a bunch
-  // of work to do. So it is not worth hiding the <void> specialization in the dylib, given that
-  // it adds deployment target restrictions.
+#  if _LIBCPP_AVAILABILITY_HAS_BAD_EXPECTED_ACCESS_KEY_FUNCTION
+  const char* what() const noexcept override;
+#  else
   _LIBCPP_HIDE_FROM_ABI_VIRTUAL const char* what() const noexcept override { return "bad access to std::expected"; }
+#  endif
 };
 _LIBCPP_DIAGNOSTIC_POP
 

libcxx/include/__functional/function.h

@@ -11,6 +11,7 @@
 #define _LIBCPP___FUNCTIONAL_FUNCTION_H
 
 #include <__assert>
+#include <__availability>
 #include <__config>
 #include <__exception/exception.h>
 #include <__functional/binary_function.h>
@@ -55,7 +56,9 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 // bad_function_call
 
 _LIBCPP_DIAGNOSTIC_PUSH
+#  if !_LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_KEY_FUNCTION
 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wweak-vtables")
+#  endif
 class _LIBCPP_EXPORTED_FROM_ABI bad_function_call : public exception {
 public:
   _LIBCPP_HIDE_FROM_ABI bad_function_call() _NOEXCEPT                                    = default;
@@ -64,7 +67,7 @@ class _LIBCPP_EXPORTED_FROM_ABI bad_function_call : public exception {
 // Note that when a key function is not used, every translation unit that uses
 // bad_function_call will end up containing a weak definition of the vtable and
 // typeinfo.
-#  ifdef _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+#  if _LIBCPP_AVAILABILITY_HAS_BAD_FUNCTION_CALL_KEY_FUNCTION
   ~bad_function_call() _NOEXCEPT override;
 #  else
   _LIBCPP_HIDE_FROM_ABI_VIRTUAL ~bad_function_call() _NOEXCEPT override {}

libcxx/lib/abi/arm64-apple-darwin.libcxxabi.v1.stable.exceptions.nonew.abilist

@@ -575,6 +575,7 @@
 {'is_defined': True, 'name': '__ZNKSt3__118__time_get_storageIcE15__do_date_orderEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '__ZNKSt3__118__time_get_storageIwE15__do_date_orderEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '__ZNKSt3__119__shared_weak_count13__get_deleterERKSt9type_info', 'type': 'FUNC'}
+{'is_defined': True, 'name': '__ZNKSt3__119bad_expected_accessIvE4whatEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '__ZNKSt3__120__codecvt_utf8_utf16IDiE10do_unshiftER11__mbstate_tPcS4_RS4_', 'type': 'FUNC'}
 {'is_defined': True, 'name': '__ZNKSt3__120__codecvt_utf8_utf16IDiE11do_encodingEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '__ZNKSt3__120__codecvt_utf8_utf16IDiE13do_max_lengthEv', 'type': 'FUNC'}
@@ -2073,6 +2074,7 @@
 {'is_defined': True, 'name': '__ZTINSt3__117moneypunct_bynameIwLb1EEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTINSt3__118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTINSt3__119__shared_weak_countE', 'size': 0, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '__ZTINSt3__119bad_expected_accessIvEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTINSt3__119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTINSt3__119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTINSt3__120__codecvt_utf8_utf16IDiEE', 'size': 0, 'type': 'OBJECT'}
@@ -2264,6 +2266,7 @@
 {'is_defined': True, 'name': '__ZTSNSt3__117moneypunct_bynameIwLb0EEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTSNSt3__117moneypunct_bynameIwLb1EEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTSNSt3__118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '__ZTSNSt3__119bad_expected_accessIvEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTSNSt3__119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTSNSt3__119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTSNSt3__13pmr15memory_resourceE', 'size': 0, 'type': 'OBJECT'}
@@ -2482,6 +2485,7 @@
 {'is_defined': True, 'name': '__ZTVNSt3__117moneypunct_bynameIwLb1EEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTVNSt3__118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTVNSt3__119__shared_weak_countE', 'size': 0, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '__ZTVNSt3__119bad_expected_accessIvEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTVNSt3__119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTVNSt3__119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 0, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '__ZTVNSt3__120__codecvt_utf8_utf16IDiEE', 'size': 0, 'type': 'OBJECT'}

libcxx/lib/abi/i686-linux-android21.libcxxabi.v1.stable.exceptions.nonew.abilist

@@ -209,6 +209,7 @@
 {'is_defined': True, 'name': '_ZNKSt6__ndk118__time_get_storageIcE15__do_date_orderEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNKSt6__ndk118__time_get_storageIwE15__do_date_orderEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNKSt6__ndk119__shared_weak_count13__get_deleterERKSt9type_info', 'type': 'FUNC'}
+{'is_defined': True, 'name': '_ZNKSt6__ndk119bad_expected_accessIvE4whatEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNKSt6__ndk120__codecvt_utf8_utf16IDiE10do_unshiftER9mbstate_tPcS4_RS4_', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNKSt6__ndk120__codecvt_utf8_utf16IDiE11do_encodingEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNKSt6__ndk120__codecvt_utf8_utf16IDiE13do_max_lengthEv', 'type': 'FUNC'}
@@ -1722,6 +1723,7 @@
 {'is_defined': True, 'name': '_ZTINSt6__ndk118__time_get_storageIwEE', 'size': 12, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTINSt6__ndk118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 12, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTINSt6__ndk119__shared_weak_countE', 'size': 24, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZTINSt6__ndk119bad_expected_accessIvEE', 'size': 12, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTINSt6__ndk119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 12, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTINSt6__ndk119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 12, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTINSt6__ndk120__codecvt_utf8_utf16IDiEE', 'size': 12, 'type': 'OBJECT'}
@@ -1958,6 +1960,7 @@
 {'is_defined': True, 'name': '_ZTSNSt6__ndk118__time_get_storageIwEE', 'size': 35, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTSNSt6__ndk118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 72, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTSNSt6__ndk119__shared_weak_countE', 'size': 33, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZTSNSt6__ndk119bad_expected_accessIvEE', 'size': 36, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTSNSt6__ndk119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 73, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTSNSt6__ndk119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 73, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTSNSt6__ndk120__codecvt_utf8_utf16IDiEE', 'size': 38, 'type': 'OBJECT'}
@@ -2188,6 +2191,7 @@
 {'is_defined': True, 'name': '_ZTVNSt6__ndk117moneypunct_bynameIwLb1EEE', 'size': 56, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTVNSt6__ndk118basic_stringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 60, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTVNSt6__ndk119__shared_weak_countE', 'size': 28, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZTVNSt6__ndk119bad_expected_accessIvEE', 'size': 20, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTVNSt6__ndk119basic_istringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 40, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTVNSt6__ndk119basic_ostringstreamIcNS_11char_traitsIcEENS_9allocatorIcEEEE', 'size': 40, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZTVNSt6__ndk120__codecvt_utf8_utf16IDiEE', 'size': 48, 'type': 'OBJECT'}

libcxx/lib/abi/powerpc-ibm-aix.libcxxabi.v1.stable.exceptions.nonew.abilist

@@ -99,6 +99,7 @@
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__118__time_get_storageIcE15__do_date_orderEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__118__time_get_storageIwE15__do_date_orderEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__119__shared_weak_count13__get_deleterERKSt9type_info', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__119bad_expected_accessIvE4whatEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__120__codecvt_utf8_utf16IDiE10do_unshiftERPcS2_S2_S3_', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__120__codecvt_utf8_utf16IDiE11do_encodingEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZNKSt3__120__codecvt_utf8_utf16IDiE13do_max_lengthEv', 'storage_mapping_class': 'DS', 'type': 'FUNC'}
@@ -910,6 +911,7 @@
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__117__widen_from_utf8ILm32EEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__117bad_function_callE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__119__shared_weak_countE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__119bad_expected_accessIvEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__120__codecvt_utf8_utf16IDiEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__120__codecvt_utf8_utf16IDsEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTINSt3__120__codecvt_utf8_utf16IwEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
@@ -969,6 +971,7 @@
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__117__widen_from_utf8ILm32EEE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__117bad_function_callE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__119__shared_weak_countE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__119bad_expected_accessIvEE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__120__codecvt_utf8_utf16IDiEE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__120__codecvt_utf8_utf16IDsEE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTSNSt3__120__codecvt_utf8_utf16IwEE', 'storage_mapping_class': 'RO', 'type': 'OBJECT'}
@@ -1031,6 +1034,7 @@
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__117__widen_from_utf8ILm32EEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__117bad_function_callE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__119__shared_weak_countE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
+{'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__119bad_expected_accessIvEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__120__codecvt_utf8_utf16IDiEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__120__codecvt_utf8_utf16IDsEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}
 {'import_export': 'EXP', 'is_defined': True, 'name': '_ZTVNSt3__120__codecvt_utf8_utf16IwEE', 'storage_mapping_class': 'RW', 'type': 'OBJECT'}