[libcxx-commits] [PATCH] D75457: Add flag _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATIONS for basic_string ABI

[Martijn Vels via Phabricator via libcxx-commits]

mvels created this revision.
mvels added reviewers: EricWF, ldionne.
Herald added subscribers: libcxx-commits, dexonsmith.
Herald added a project: libc++.

This review is a mostly trivial change to use an explicit ABI flag for the unstable external template list. This follows the practice for an ABI flag per feature, and provides a spot for the rational / motivation for the flag.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D75457

Files:
  libcxx/include/__config
  libcxx/include/string
  libcxx/src/string.cpp


Index: libcxx/src/string.cpp
===================================================================
--- libcxx/src/string.cpp
+++ libcxx/src/string.cpp
@@ -20,7 +20,7 @@
 
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __basic_string_common<true>;
 
-#if defined(_LIBCPP_ABI_UNSTABLE) || _LIBCPP_ABI_VERSION >= 2
+#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
 _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
 _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
 #else
Index: libcxx/include/string
===================================================================
--- libcxx/include/string
+++ libcxx/include/string
@@ -4381,7 +4381,7 @@
 
 #endif  // _LIBCPP_DEBUG_LEVEL >= 2
 
-#if defined(_LIBCPP_ABI_UNSTABLE) || _LIBCPP_ABI_VERSION >= 2
+#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
 _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, char)
 _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, wchar_t)
 #else
Index: libcxx/include/__config
===================================================================
--- libcxx/include/__config
+++ libcxx/include/__config
@@ -102,6 +102,9 @@
 #  define _LIBCPP_ABI_OPTIMIZED_FUNCTION
 // All the regex constants must be distinct and nonzero.
 #  define _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
+// Re-worked external template instantiations for std::string with a focus on
+// performance and fast-path inlining.
+#  define _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
 #elif _LIBCPP_ABI_VERSION == 1
 #  if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
 // Enable compiling copies of now inline methods into the dylib to support


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