From 7f4c37099a9f2415e00e94379c1206b3e9185c52 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Fri, 16 Sep 2022 21:29:44 +0100
Subject: [PATCH] libstdc++: Move allocator-related helpers to
 <bits/alloc_traits.h>

The __alloc_swap and __shrink_to_fit_aux helpers are not specific to
std::allocator, so don't belong in <bits/allocator.h>. This also
simplifies enabling <memory> for freestanding, as now we can just omit
the whole of <bits/allocator.h> for freestanding.

libstdc++-v3/ChangeLog:

	* include/bits/alloc_traits.h (__alloc_swap)
	(__shrink_to_fit_aux): Move here, from ...
	* include/bits/allocator.h: ... here.
	* include/ext/alloc_traits.h: Do not include allocator.h.
---
 libstdc++-v3/include/bits/alloc_traits.h | 48 ++++++++++++++++++++++
 libstdc++-v3/include/bits/allocator.h    | 51 ------------------------
 libstdc++-v3/include/ext/alloc_traits.h  |  3 --
 3 files changed, 48 insertions(+), 54 deletions(-)

diff --git a/libstdc++-v3/include/bits/alloc_traits.h b/libstdc++-v3/include/bits/alloc_traits.h
index f9ca37fd7d6..35bdf6ecf98 100644
--- a/libstdc++-v3/include/bits/alloc_traits.h
+++ b/libstdc++-v3/include/bits/alloc_traits.h
@@ -824,6 +824,54 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   /// @cond undocumented
 
+  // To implement Option 3 of DR 431.
+  template<typename _Alloc, bool = __is_empty(_Alloc)>
+    struct __alloc_swap
+    { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
+
+  template<typename _Alloc>
+    struct __alloc_swap<_Alloc, false>
+    {
+      static void
+      _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
+      {
+	// Precondition: swappable allocators.
+	if (__one != __two)
+	  swap(__one, __two);
+      }
+    };
+
+#if __cplusplus >= 201103L
+  template<typename _Tp, bool
+    = __or_<is_copy_constructible<typename _Tp::value_type>,
+            is_nothrow_move_constructible<typename _Tp::value_type>>::value>
+    struct __shrink_to_fit_aux
+    { static bool _S_do_it(_Tp&) noexcept { return false; } };
+
+  template<typename _Tp>
+    struct __shrink_to_fit_aux<_Tp, true>
+    {
+      _GLIBCXX20_CONSTEXPR
+      static bool
+      _S_do_it(_Tp& __c) noexcept
+      {
+#if __cpp_exceptions
+	try
+	  {
+	    _Tp(__make_move_if_noexcept_iterator(__c.begin()),
+		__make_move_if_noexcept_iterator(__c.end()),
+		__c.get_allocator()).swap(__c);
+	    return true;
+	  }
+	catch(...)
+	  { return false; }
+#else
+	return false;
+#endif
+      }
+    };
+#endif
+
   /**
    * Destroy a range of objects using the supplied allocator.  For
    * non-default allocators we do not optimize away invocation of
diff --git a/libstdc++-v3/include/bits/allocator.h b/libstdc++-v3/include/bits/allocator.h
index c39166e24fe..54f5acf85d7 100644
--- a/libstdc++-v3/include/bits/allocator.h
+++ b/libstdc++-v3/include/bits/allocator.h
@@ -279,57 +279,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Undefine.
 #undef __allocator_base
 
-  /// @cond undocumented
-
-  // To implement Option 3 of DR 431.
-  template<typename _Alloc, bool = __is_empty(_Alloc)>
-    struct __alloc_swap
-    { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
-
-  template<typename _Alloc>
-    struct __alloc_swap<_Alloc, false>
-    {
-      static void
-      _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
-      {
-	// Precondition: swappable allocators.
-	if (__one != __two)
-	  swap(__one, __two);
-      }
-    };
-
-#if __cplusplus >= 201103L
-  template<typename _Tp, bool
-    = __or_<is_copy_constructible<typename _Tp::value_type>,
-            is_nothrow_move_constructible<typename _Tp::value_type>>::value>
-    struct __shrink_to_fit_aux
-    { static bool _S_do_it(_Tp&) noexcept { return false; } };
-
-  template<typename _Tp>
-    struct __shrink_to_fit_aux<_Tp, true>
-    {
-      _GLIBCXX20_CONSTEXPR
-      static bool
-      _S_do_it(_Tp& __c) noexcept
-      {
-#if __cpp_exceptions
-	try
-	  {
-	    _Tp(__make_move_if_noexcept_iterator(__c.begin()),
-		__make_move_if_noexcept_iterator(__c.end()),
-		__c.get_allocator()).swap(__c);
-	    return true;
-	  }
-	catch(...)
-	  { return false; }
-#else
-	return false;
-#endif
-      }
-    };
-#endif
-  /// @endcond
-
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
diff --git a/libstdc++-v3/include/ext/alloc_traits.h b/libstdc++-v3/include/ext/alloc_traits.h
index 1d7d9598cb2..c9547c7305c 100644
--- a/libstdc++-v3/include/ext/alloc_traits.h
+++ b/libstdc++-v3/include/ext/alloc_traits.h
@@ -32,9 +32,6 @@
 #pragma GCC system_header
 
 # include <bits/alloc_traits.h>
-#if __cplusplus < 201103L
-# include <bits/allocator.h>  // for __alloc_swap
-#endif
 
 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
 {