[libc++] Instantiate additional <iostream> members in the dylib
This commit adds new explicit instantiations for some classes in <iostream>
in the library. This is done after noticing that many programs that use
streams end up containing weak definitions of these classes, which has a
negative impact on both code size and load times (due to the need to
resolve weak symbols at load time). Note that we are just adding the
additional explicit instantiations for the `char` specializations, since
the `wchar_t` specializations are not used as often, and as a result there
wouldn't be a clear benefit.
This change is not an ABI break, since we are just adding additional
symbols.
Differential Revision: https://reviews.llvm.org/D90677
GitOrigin-RevId: 997d41cdec536a0b632505d9b0c4ab5dec5d7d12
diff --git a/include/sstream b/include/sstream
index 042766c..1439d9c 100644
--- a/include/sstream
+++ b/include/sstream
@@ -836,6 +836,13 @@
__x.swap(__y);
}
+#if defined(_LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_stringbuf<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_stringstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ostringstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_istringstream<char>)
+#endif
+
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS