libstdc++: Implement P3235R3 optimizations for std::print [PR121790]

This patch implements additional enable_nonlocking_formatter_optimization
specializations listed in P3235R3.

	PR libstdc++/121790

libstdc++-v3/ChangeLog:

	* include/bits/chrono_io.h
	(enable_nonlocking_formatter_optimization): Define specializations
	for chrono types.
	* include/bits/version.def (print): Bump.
	* include/bits/version.h: Regenerate.
	* include/std/format (enable_nonlocking_formatter_optimization):
	Define specializations for pair, tuple and ranges.
	* include/std/queue (enable_nonlocking_formatter_optimization):
	Define specializations for queue and priority_queue.
	* include/std/stack (enable_nonlocking_formatter_optimization):
	Define specialization for stack.
	* include/std/stacktrace (enable_nonlocking_formatter_optimization):
	Define specialization for basic_stacktrace and stacktrace_entry.
	* include/std/thread (enable_nonlocking_formatter_optimization):
	Define specialization for thread::id.
	* include/std/vector (enable_nonlocking_formatter_optimization):
	Define specialization for vector<bool>::reference.
	* testsuite/23_containers/vector/bool/format.cc: Test value of
	enable_nonlocking_formatter_optimization.
	* testsuite/30_threads/thread/id/output.cc: Likewise.
	* testsuite/std/format/ranges/adaptors.cc: Likewise.
	* testsuite/std/format/ranges/formatter.cc: Likewise.
	* testsuite/std/format/tuple.cc: Likewise.
	* testsuite/std/time/format/empty_spec.cc: Extract Rep class
	to custom_rep.h.
	* testsuite/std/time/format/custom_rep.h: Extracted from
	empty_spec.cc.
	* testsuite/std/time/format/nonlocking.cc: New test.

Reviewed-by: Jonathan Wakely <jwakely@redhat.com>

3 files changed, 60 insertions, 1 deletions

diff --git a/libstdc++-v3/testsuite/std/format/ranges/adaptors.cc b/libstdc++-v3/testsuite/std/format/ranges/adaptors.cc
index a4e2dfb3321..d9fc01ab893 100644
--- a/libstdc++-v3/testsuite/std/format/ranges/adaptors.cc
+++ b/libstdc++-v3/testsuite/std/format/ranges/adaptors.cc
@@ -121,6 +121,16 @@ test_output()
 
   // Formatter check if container is formattable, not container elements.
   static_assert(!std::formattable<Adaptor<int, NotFormattableCont<int>>, CharT>);
+
+  // TODO should be false
+  static_assert(std::enable_nonlocking_formatter_optimization<
+		  Adaptor<int>>);
+  static_assert(std::enable_nonlocking_formatter_optimization<
+		  Adaptor<MutFormat>>);
+  static_assert(std::enable_nonlocking_formatter_optimization<
+		  Adaptor<int, std::deque<int>>>);
+  static_assert(std::enable_nonlocking_formatter_optimization<
+		  Adaptor<int, NotFormattableCont<int>>>);
 }
 
 template<template<typename Tp, typename Cont = std::vector<Tp>> class Adaptor>
diff --git a/libstdc++-v3/testsuite/std/format/ranges/formatter.cc b/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
index d3e089767bf..a50c5b1033f 100644
--- a/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
+++ b/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
@@ -4,6 +4,7 @@
 #include <format>
 #include <testsuite_hooks.h>
 #include <vector>
+#include <span>
 
 #define WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
 #define WIDEN(S) WIDEN_(CharT, S)
@@ -145,7 +146,7 @@ struct MyFlatMap : std::flat_map<int, int>
 
 template<typename CharT>
 struct std::formatter<MyFlatMap, CharT>
-  // This cannot apply format BitVector const&, because formatted type would
+  // We cannot format MyFlatMap const&, because formatted type would
   // be std::pair<int const&, int const&>, and formatter for
   // pair<int const&, int> cannot format it.
   : std::range_formatter<MyFlatMap::reference>
@@ -161,10 +162,21 @@ void test_const_ref_type_mismatch()
 template<typename T, typename CharT>
 using VectorFormatter = std::formatter<std::vector<T>, CharT>;
 
+template<template<typename> typename Range>
+void test_nonblocking()
+{
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Range<int>>);
+}
+
 int main()
 {
   test_outputs<std::range_formatter>();
   test_outputs<VectorFormatter>();
   test_nested();
   test_const_ref_type_mismatch();
+
+  test_nonblocking<std::span>();
+  test_nonblocking<std::vector>();
+  test_nonblocking<MyVector>();
 }
diff --git a/libstdc++-v3/testsuite/std/format/tuple.cc b/libstdc++-v3/testsuite/std/format/tuple.cc
index ba6dae8935b..001235ba643 100644
--- a/libstdc++-v3/testsuite/std/format/tuple.cc
+++ b/libstdc++-v3/testsuite/std/format/tuple.cc
@@ -341,6 +341,40 @@ void test_padding()
   VERIFY( check_elems(resv) );
 }
 
+struct Custom {};
+
+template<typename CharT>
+struct std::formatter<Custom, CharT>
+{
+  constexpr std::basic_format_parse_context<CharT>::iterator
+  parse(const std::basic_format_parse_context<CharT>& pc)
+  { return pc.begin();  }
+
+  template<typename Out>
+  typename std::basic_format_context<Out, CharT>::iterator
+  format(Custom, const std::basic_format_context<Out, CharT>& fc) const
+  { return fc.out(); }
+};
+
+template<template<typename...> typename Tuple>
+void test_nonblocking()
+{
+  static_assert(std::enable_nonlocking_formatter_optimization<
+		  Tuple<int, float>>);
+  // TODO missing remove_cv_ref
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Tuple<const int, const float>>);
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Tuple<int&, float&>>);
+
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Tuple<Custom, float>>);
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Tuple<const Custom, const float>>);
+  static_assert(!std::enable_nonlocking_formatter_optimization<
+		  Tuple<Custom&, float&>>);
+}
+
 int main()
 {
   test_format_string();
@@ -348,4 +382,7 @@ int main()
   test_outputs<wchar_t>();
   test_nested();
   test_padding();
+
+  test_nonblocking<std::pair>();
+  test_nonblocking<std::tuple>();
 }