1 files changed, 24 insertions, 10 deletions

diff --git a/libcxx/include/__format/formatter_string.h b/libcxx/include/__format/formatter_string.h
index 71bda4fcded1..606fb792499c 100644
--- a/libcxx/include/__format/formatter_string.h
+++ b/libcxx/include/__format/formatter_string.h
@@ -12,7 +12,7 @@
 
 #include <__availability>
 #include <__config>
-#include <__format/format_fwd.h>
+#include <__format/concepts.h>
 #include <__format/format_parse_context.h>
 #include <__format/formatter.h>
 #include <__format/formatter_output.h>
@@ -29,7 +29,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER > 17
 
-template <__formatter::__char_type _CharT>
+template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS __formatter_string {
 public:
   _LIBCPP_HIDE_FROM_ABI constexpr auto parse(basic_format_parse_context<_CharT>& __parse_ctx)
@@ -40,14 +40,23 @@ public:
   }
 
   _LIBCPP_HIDE_FROM_ABI auto format(basic_string_view<_CharT> __str, auto& __ctx) const -> decltype(__ctx.out()) {
+#  if _LIBCPP_STD_VER > 20
+    if (__parser_.__type_ == __format_spec::__type::__debug)
+      return __formatter::__format_escaped_string(__str, __ctx.out(), __parser_.__get_parsed_std_specifications(__ctx));
+#  endif
+
     return __formatter::__write_string(__str, __ctx.out(), __parser_.__get_parsed_std_specifications(__ctx));
   }
 
-  __format_spec::__parser<_CharT> __parser_;
+#  if _LIBCPP_STD_VER > 20
+  _LIBCPP_HIDE_FROM_ABI constexpr void set_debug_format() { __parser_.__type_ = __format_spec::__type::__debug; }
+#  endif
+
+  __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};
 };
 
 // Formatter const char*.
-template <__formatter::__char_type _CharT>
+template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT*, _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;
@@ -56,6 +65,12 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT*,
     _LIBCPP_ASSERT(__str, "The basic_format_arg constructor should have "
                           "prevented an invalid pointer.");
 
+    __format_spec::__parsed_specifications<_CharT> __specs = _Base::__parser_.__get_parsed_std_specifications(__ctx);
+#  if _LIBCPP_STD_VER > 20
+    if (_Base::__parser_.__type_ == __format_spec::__type::__debug)
+      return __formatter::__format_escaped_string(basic_string_view<_CharT>{__str}, __ctx.out(), __specs);
+#  endif
+
     // When using a center or right alignment and the width option the length
     // of __str must be known to add the padding upfront. This case is handled
     // by the base class by converting the argument to a basic_string_view.
@@ -67,7 +82,6 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT*,
     // now these optimizations aren't implemented. Instead the base class
     // handles these options.
     // TODO FMT Implement these improvements.
-    __format_spec::__parsed_specifications<_CharT> __specs = _Base::__parser_.__get_parsed_std_specifications(__ctx);
     if (__specs.__has_width() || __specs.__has_precision())
       return __formatter::__write_string(basic_string_view<_CharT>{__str}, __ctx.out(), __specs);
 
@@ -80,7 +94,7 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT*,
 };
 
 // Formatter char*.
-template <__formatter::__char_type _CharT>
+template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<_CharT*, _CharT>
     : public formatter<const _CharT*, _CharT> {
   using _Base = formatter<const _CharT*, _CharT>;
@@ -91,7 +105,7 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<_CharT*, _Char
 };
 
 // Formatter char[].
-template <__formatter::__char_type _CharT, size_t _Size>
+template <__fmt_char_type _CharT, size_t _Size>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<_CharT[_Size], _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;
@@ -102,7 +116,7 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<_CharT[_Size],
 };
 
 // Formatter const char[].
-template <__formatter::__char_type _CharT, size_t _Size>
+template <__fmt_char_type _CharT, size_t _Size>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT[_Size], _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;
@@ -113,7 +127,7 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT[_
 };
 
 // Formatter std::string.
-template <__formatter::__char_type _CharT, class _Traits, class _Allocator>
+template <__fmt_char_type _CharT, class _Traits, class _Allocator>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<basic_string<_CharT, _Traits, _Allocator>, _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;
@@ -126,7 +140,7 @@ struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<basic_string<_
 };
 
 // Formatter std::string_view.
-template <__formatter::__char_type _CharT, class _Traits>
+template <__fmt_char_type _CharT, class _Traits>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<basic_string_view<_CharT, _Traits>, _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;