[libc++] Simplify the implementation of iostream.cpp (#124103)

This refactors the standard stream implementation in multiple ways:
- The streams are now `stream_data` structs, which contain all the data
required for a stream
- The windows mangling is generated via a macro instead of having magic
strings for the different streams. (i.e. it's now only partially magic)

6 files changed, 103 insertions, 138 deletions

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 93f91f3..b38cedb 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
@@ -1221,7 +1221,7 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk131__arrive_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseEh', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk132__destroy_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk134__construct_barrier_algorithm_baseERi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk13cinE', 'size': 88, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk13cinE', 'size': 148, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD0Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD1Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD2Ev', 'type': 'FUNC'}
@@ -1289,9 +1289,9 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__removeERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__renameERKNS1_4pathES4_PNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__statusERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14cerrE', 'size': 84, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14clogE', 'size': 84, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14coutE', 'size': 84, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14cerrE', 'size': 136, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14clogE', 'size': 136, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14coutE', 'size': 136, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stodERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPj', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stodERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPj', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stofERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPj', 'type': 'FUNC'}
@@ -1300,7 +1300,7 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk14stoiERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPji', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stolERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPji', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stolERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPji', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14wcinE', 'size': 88, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14wcinE', 'size': 148, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15alignEjjRPvRj', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15ctypeIcE10table_sizeE', 'size': 4, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15ctypeIcE13classic_tableEv', 'type': 'FUNC'}
@@ -1325,9 +1325,9 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk15stollERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPji', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15stoulERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPji', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15stoulERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPji', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wcerrE', 'size': 84, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wclogE', 'size': 84, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wcoutE', 'size': 84, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wcerrE', 'size': 136, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wclogE', 'size': 136, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wcoutE', 'size': 136, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__clocEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__itoa8__u32toaEjPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__itoa8__u64toaEyPc', '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 00c9f31..5c8329c 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
@@ -1221,7 +1221,7 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk131__arrive_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseEh', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk132__destroy_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk134__construct_barrier_algorithm_baseERl', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk13cinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk13cinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD0Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD1Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk13pmr15memory_resourceD2Ev', 'type': 'FUNC'}
@@ -1289,9 +1289,9 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__removeERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__renameERKNS1_4pathES4_PNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14__fs10filesystem8__statusERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14cerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14clogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14coutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14cerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14clogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14coutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stodERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stodERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stofERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
@@ -1300,7 +1300,7 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk14stoiERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stolERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk14stolERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk14wcinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk14wcinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15alignEmmRPvRm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15ctypeIcE10table_sizeE', 'size': 8, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15ctypeIcE13classic_tableEv', 'type': 'FUNC'}
@@ -1325,9 +1325,9 @@
 {'is_defined': True, 'name': '_ZNSt6__ndk15stollERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15stoulERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk15stoulERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wcerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wclogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt6__ndk15wcoutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wcerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wclogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt6__ndk15wcoutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__clocEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__itoa8__u32toaEjPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt6__ndk16__itoa8__u64toaEmPc', '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 0fbc1a2..3b2f99a 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
@@ -1236,7 +1236,7 @@
 {'is_defined': True, 'name': '_ZNSt3__131__arrive_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseEh', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__132__destroy_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__134__construct_barrier_algorithm_baseERl', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD0Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD1Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD2Ev', 'type': 'FUNC'}
@@ -1304,9 +1304,9 @@
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__removeERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__renameERKNS1_4pathES4_PNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__statusERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stofERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
@@ -1315,7 +1315,7 @@
 {'is_defined': True, 'name': '_ZNSt3__14stoiERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15alignEmmRPvRm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE10table_sizeE', 'size': 8, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE13classic_tableEv', 'type': 'FUNC'}
@@ -1340,9 +1340,9 @@
 {'is_defined': True, 'name': '_ZNSt3__15stollERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u32toaEjPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u64toaEmPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__sortIRNS_6__lessIaaEEPaEEvT0_S5_T_', '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 83b18bb..3aa9e50 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
@@ -1234,7 +1234,7 @@
 {'is_defined': True, 'name': '_ZNSt3__131__arrive_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseEh', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__132__destroy_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__134__construct_barrier_algorithm_baseERl', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD0Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD1Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD2Ev', 'type': 'FUNC'}
@@ -1302,9 +1302,9 @@
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__removeERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__renameERKNS1_4pathES4_PNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__statusERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stofERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
@@ -1313,7 +1313,7 @@
 {'is_defined': True, 'name': '_ZNSt3__14stoiERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15alignEmmRPvRm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE10table_sizeE', 'size': 8, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE13classic_tableEv', 'type': 'FUNC'}
@@ -1340,9 +1340,9 @@
 {'is_defined': True, 'name': '_ZNSt3__15stollERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__16__clocEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u32toaEjPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u64toaEmPc', '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 3bf0eb0..74681c2 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
@@ -1205,7 +1205,7 @@
 {'is_defined': True, 'name': '_ZNSt3__131__arrive_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseEh', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__132__destroy_barrier_algorithm_baseEPNS_24__barrier_algorithm_baseE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__134__construct_barrier_algorithm_baseERl', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__13cinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD0Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD1Ev', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__13pmr15memory_resourceD2Ev', 'type': 'FUNC'}
@@ -1273,9 +1273,9 @@
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__removeERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__renameERKNS1_4pathES4_PNS_10error_codeE', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14__fs10filesystem8__statusERKNS1_4pathEPNS_10error_codeE', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14cerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14clogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14coutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stodERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stofERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPm', 'type': 'FUNC'}
@@ -1284,7 +1284,7 @@
 {'is_defined': True, 'name': '_ZNSt3__14stoiERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__14stolERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 168, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__14wcinE', 'size': 280, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15alignEmmRPvRm', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE10table_sizeE', 'size': 8, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__15ctypeIcE13classic_tableEv', 'type': 'FUNC'}
@@ -1311,9 +1311,9 @@
 {'is_defined': True, 'name': '_ZNSt3__15stollERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEEEPmi', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__15stoulERKNS_12basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEEEPmi', 'type': 'FUNC'}
-{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 160, 'type': 'OBJECT'}
-{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 160, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcerrE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wclogE', 'size': 264, 'type': 'OBJECT'}
+{'is_defined': True, 'name': '_ZNSt3__15wcoutE', 'size': 264, 'type': 'OBJECT'}
 {'is_defined': True, 'name': '_ZNSt3__16__clocEv', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u32toaEjPc', 'type': 'FUNC'}
 {'is_defined': True, 'name': '_ZNSt3__16__itoa8__u64toaEmPc', 'type': 'FUNC'}
diff --git a/libcxx/src/iostream.cpp b/libcxx/src/iostream.cpp
index 9bc9ec0..d91f9f0 100644
--- a/libcxx/src/iostream.cpp
+++ b/libcxx/src/iostream.cpp
@@ -7,90 +7,58 @@
 //===----------------------------------------------------------------------===//
 
 #include "std_stream.h"
-#include <__locale>
-#include <new>
-#include <string>
 
-#define _str(s) #s
-#define str(s) _str(s)
-#define _LIBCPP_ABI_NAMESPACE_STR str(_LIBCPP_ABI_NAMESPACE)
+#include <__memory/construct_at.h>
+#include <__ostream/basic_ostream.h>
+#include <istream>
 
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-alignas(istream) _LIBCPP_EXPORTED_FROM_ABI char cin[sizeof(istream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?cin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#endif
-        ;
-alignas(__stdinbuf<char>) static char __cin[sizeof(__stdinbuf<char>)];
-static mbstate_t mb_cin;
-
-#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wistream) _LIBCPP_EXPORTED_FROM_ABI char wcin[sizeof(wistream)]
-#  if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?wcin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#  endif
-        ;
-alignas(__stdinbuf<wchar_t>) static char __wcin[sizeof(__stdinbuf<wchar_t>)];
-static mbstate_t mb_wcin;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
+#define ABI_NAMESPACE_STR _LIBCPP_TOSTRING(_LIBCPP_ABI_NAMESPACE)
 
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char cout[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?cout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#endif
-        ;
-alignas(__stdoutbuf<char>) static char __cout[sizeof(__stdoutbuf<char>)];
-static mbstate_t mb_cout;
+_LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wcout[sizeof(wostream)]
-#  if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?wcout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#  endif
-        ;
-alignas(__stdoutbuf<wchar_t>) static char __wcout[sizeof(__stdoutbuf<wchar_t>)];
-static mbstate_t mb_wcout;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
+template <class StreamT, class BufferT>
+union stream_data {
+  stream_data() {}
+  ~stream_data() {}
+  struct {
+    // The stream has to be the first element, since that's referenced by the stream declarations in <iostream>
+    StreamT stream;
+    BufferT buffer;
+    mbstate_t mb;
+  };
+
+  void init(FILE* stdstream) {
+    mb = {};
+    std::construct_at(&buffer, stdstream, &mb);
+    std::construct_at(&stream, &buffer);
+  }
+};
 
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char cerr[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?cerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
+#define CHAR_MANGLING_char "D"
+#define CHAR_MANGLING_wchar_t "_W"
+#define CHAR_MANGLING(CharT) CHAR_MANGLING_##CharT
+
+#ifdef _LIBCPP_ABI_MICROSOFT
+#  define STREAM(StreamT, BufferT, CharT, var)                                                                         \
+    stream_data<StreamT<CharT>, BufferT<CharT>> var __asm__(                                                           \
+        "?" #var "@" ABI_NAMESPACE_STR "@std@@3V?$" #StreamT                                                           \
+        "@" CHAR_MANGLING(CharT) "U?$char_traits@" CHAR_MANGLING(CharT) "@" ABI_NAMESPACE_STR "@std@@@12@A")
+#else
+#  define STREAM(StreamT, BufferT, CharT, var) stream_data<StreamT<CharT>, BufferT<CharT>> var
 #endif
-        ;
-alignas(__stdoutbuf<char>) static char __cerr[sizeof(__stdoutbuf<char>)];
-static mbstate_t mb_cerr;
-
-#if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wcerr[sizeof(wostream)]
-#  if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?wcerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#  endif
-        ;
-alignas(__stdoutbuf<wchar_t>) static char __wcerr[sizeof(__stdoutbuf<wchar_t>)];
-static mbstate_t mb_wcerr;
-#endif // _LIBCPP_HAS_WIDE_CHARACTERS
 
-alignas(ostream) _LIBCPP_EXPORTED_FROM_ABI char clog[sizeof(ostream)]
-#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?clog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#endif
-        ;
+// These definitions and the declarations in <iostream> technically cause ODR violations, since they have different
+// types (stream_data and {i,o}stream respectively). This means that <iostream> should never be included in this TU.
 
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_istream, __stdinbuf, char, cin);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, char, cout);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, char, cerr);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, char, clog);
 #if _LIBCPP_HAS_WIDE_CHARACTERS
-alignas(wostream) _LIBCPP_EXPORTED_FROM_ABI char wclog[sizeof(wostream)]
-#  if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
-    __asm__("?wclog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR
-            "@std@@@12@A")
-#  endif
-        ;
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_istream, __stdinbuf, wchar_t, wcin);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, wchar_t, wcout);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, wchar_t, wcerr);
+_LIBCPP_EXPORTED_FROM_ABI STREAM(basic_ostream, __stdoutbuf, wchar_t, wclog);
 #endif // _LIBCPP_HAS_WIDE_CHARACTERS
 
 // Pretend we're inside a system header so the compiler doesn't flag the use of the init_priority
@@ -124,37 +92,34 @@ public:
 DoIOSInit::DoIOSInit() {
   force_locale_initialization();
 
-  istream* cin_ptr  = ::new (cin) istream(::new (__cin) __stdinbuf<char>(stdin, &mb_cin));
-  ostream* cout_ptr = ::new (cout) ostream(::new (__cout) __stdoutbuf<char>(stdout, &mb_cout));
-  ostream* cerr_ptr = ::new (cerr) ostream(::new (__cerr) __stdoutbuf<char>(stderr, &mb_cerr));
-  ::new (clog) ostream(cerr_ptr->rdbuf());
-  cin_ptr->tie(cout_ptr);
-  std::unitbuf(*cerr_ptr);
-  cerr_ptr->tie(cout_ptr);
+  cin.init(stdin);
+  cout.init(stdout);
+  cerr.init(stderr);
+  clog.init(stderr);
+
+  cin.stream.tie(&cout.stream);
+  std::unitbuf(cerr.stream);
+  cerr.stream.tie(&cout.stream);
 
 #if _LIBCPP_HAS_WIDE_CHARACTERS
-  wistream* wcin_ptr  = ::new (wcin) wistream(::new (__wcin) __stdinbuf<wchar_t>(stdin, &mb_wcin));
-  wostream* wcout_ptr = ::new (wcout) wostream(::new (__wcout) __stdoutbuf<wchar_t>(stdout, &mb_wcout));
-  wostream* wcerr_ptr = ::new (wcerr) wostream(::new (__wcerr) __stdoutbuf<wchar_t>(stderr, &mb_wcerr));
-  ::new (wclog) wostream(wcerr_ptr->rdbuf());
-
-  wcin_ptr->tie(wcout_ptr);
-  std::unitbuf(*wcerr_ptr);
-  wcerr_ptr->tie(wcout_ptr);
+  wcin.init(stdin);
+  wcout.init(stdout);
+  wcerr.init(stderr);
+  wclog.init(stderr);
+
+  wcin.stream.tie(&wcout.stream);
+  std::unitbuf(wcerr.stream);
+  wcerr.stream.tie(&wcout.stream);
 #endif
 }
 
 DoIOSInit::~DoIOSInit() {
-  ostream* cout_ptr = reinterpret_cast<ostream*>(cout);
-  cout_ptr->flush();
-  ostream* clog_ptr = reinterpret_cast<ostream*>(clog);
-  clog_ptr->flush();
+  cout.stream.flush();
+  clog.stream.flush();
 
 #if _LIBCPP_HAS_WIDE_CHARACTERS
-  wostream* wcout_ptr = reinterpret_cast<wostream*>(wcout);
-  wcout_ptr->flush();
-  wostream* wclog_ptr = reinterpret_cast<wostream*>(wclog);
-  wclog_ptr->flush();
+  wcout.stream.flush();
+  wclog.stream.flush();
 #endif
 }