[libc++] Remove unnecessary friend declarations from <__tree>

[philnik777]

Removing the unnecessary friend declarations from <__tree> also removes the need for forward declaration headers for map and set, which this patch also removes.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

Removing the unnecessary friend declarations from <__tree> also removes the need for forward declaration headers for map and set, which this patch also removes.

---

Full diff: https://github.com/llvm/llvm-project/pull/152133.diff

7 Files Affected:

• (modified) libcxx/include/CMakeLists.txt (-2)
• (removed) libcxx/include/__fwd/map.h (-31)
• (removed) libcxx/include/__fwd/set.h (-30)
• (modified) libcxx/include/__tree (+6-31)
• (modified) libcxx/include/map (+4-2)
• (modified) libcxx/include/module.modulemap.in (-2)
• (modified) libcxx/include/set (+4-2)

diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 51444ec668e2b..c6b87a34a43e9 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -447,14 +447,12 @@ set(files
   __fwd/get.h
   __fwd/ios.h
   __fwd/istream.h
-  __fwd/map.h
   __fwd/mdspan.h
   __fwd/memory.h
   __fwd/memory_resource.h
   __fwd/ostream.h
   __fwd/pair.h
   __fwd/queue.h
-  __fwd/set.h
   __fwd/span.h
   __fwd/sstream.h
   __fwd/stack.h
diff --git a/libcxx/include/__fwd/map.h b/libcxx/include/__fwd/map.h
deleted file mode 100644
index 940298dd3e563..0000000000000
--- a/libcxx/include/__fwd/map.h
+++ /dev/null
@@ -1,31 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP___FWD_MAP_H
-#define _LIBCPP___FWD_MAP_H
-
-#include <__config>
-#include <__fwd/functional.h>
-#include <__fwd/memory.h>
-#include <__fwd/pair.h>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-template <class _Key, class _Tp, class _Compare = less<_Key>, class _Allocator = allocator<pair<const _Key, _Tp> > >
-class map;
-
-template <class _Key, class _Tp, class _Compare = less<_Key>, class _Allocator = allocator<pair<const _Key, _Tp> > >
-class multimap;
-
-_LIBCPP_END_NAMESPACE_STD
-
-#endif // _LIBCPP___FWD_MAP_H
diff --git a/libcxx/include/__fwd/set.h b/libcxx/include/__fwd/set.h
deleted file mode 100644
index d5ef8d56b0015..0000000000000
--- a/libcxx/include/__fwd/set.h
+++ /dev/null
@@ -1,30 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP___FWD_SET_H
-#define _LIBCPP___FWD_SET_H
-
-#include <__config>
-#include <__fwd/functional.h>
-#include <__fwd/memory.h>
-
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
-#  pragma GCC system_header
-#endif
-
-_LIBCPP_BEGIN_NAMESPACE_STD
-
-template <class _Key, class _Compare = less<_Key>, class _Allocator = allocator<_Key> >
-class set;
-
-template <class _Key, class _Compare = less<_Key>, class _Allocator = allocator<_Key> >
-class multiset;
-
-_LIBCPP_END_NAMESPACE_STD
-
-#endif // _LIBCPP___FWD_SET_H
diff --git a/libcxx/include/__tree b/libcxx/include/__tree
index 1b1bb538029da..153db9b73006b 100644
--- a/libcxx/include/__tree
+++ b/libcxx/include/__tree
@@ -13,9 +13,7 @@
 #include <__algorithm/min.h>
 #include <__assert>
 #include <__config>
-#include <__fwd/map.h>
 #include <__fwd/pair.h>
-#include <__fwd/set.h>
 #include <__iterator/distance.h>
 #include <__iterator/iterator_traits.h>
 #include <__iterator/next.h>
@@ -686,16 +684,6 @@ private:
   friend class __tree;
   template <class, class, class>
   friend class __tree_const_iterator;
-  template <class>
-  friend class __map_iterator;
-  template <class, class, class, class>
-  friend class map;
-  template <class, class, class, class>
-  friend class multimap;
-  template <class, class, class>
-  friend class set;
-  template <class, class, class>
-  friend class multiset;
 };
 
 template <class _Tp, class _NodePtr, class _DiffType>
@@ -709,18 +697,15 @@ class __tree_const_iterator {
   __end_node_pointer __ptr_;
 
 public:
-  using iterator_category = bidirectional_iterator_tag;
-  using value_type        = __get_node_value_type_t<_Tp>;
-  using difference_type   = _DiffType;
-  using reference         = const value_type&;
-  using pointer           = __rebind_pointer_t<_NodePtr, const value_type>;
+  using iterator_category                    = bidirectional_iterator_tag;
+  using value_type                           = __get_node_value_type_t<_Tp>;
+  using difference_type                      = _DiffType;
+  using reference                            = const value_type&;
+  using pointer                              = __rebind_pointer_t<_NodePtr, const value_type>;
+  using __non_const_iterator _LIBCPP_NODEBUG = __tree_iterator<_Tp, __node_pointer, difference_type>;
 
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator() _NOEXCEPT : __ptr_(nullptr) {}
 
-private:
-  typedef __tree_iterator<_Tp, __node_pointer, difference_type> __non_const_iterator;
-
-public:
   _LIBCPP_HIDE_FROM_ABI __tree_const_iterator(__non_const_iterator __p) _NOEXCEPT : __ptr_(__p.__ptr_) {}
 
   _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __get_np()->__value_; }
@@ -762,16 +747,6 @@ private:
 
   template <class, class, class>
   friend class __tree;
-  template <class, class, class, class>
-  friend class map;
-  template <class, class, class, class>
-  friend class multimap;
-  template <class, class, class>
-  friend class set;
-  template <class, class, class>
-  friend class multiset;
-  template <class>
-  friend class __map_const_iterator;
 };
 
 template <class _Tp, class _Compare>
diff --git a/libcxx/include/map b/libcxx/include/map
index 0a43bd09a0b16..6378218945ca0 100644
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -582,7 +582,6 @@ erase_if(multimap<Key, T, Compare, Allocator>& c, Predicate pred);  // C++20
 #  include <__functional/binary_function.h>
 #  include <__functional/is_transparent.h>
 #  include <__functional/operations.h>
-#  include <__fwd/map.h>
 #  include <__iterator/erase_if_container.h>
 #  include <__iterator/iterator_traits.h>
 #  include <__iterator/ranges_iterator_traits.h>
@@ -861,7 +860,10 @@ public:
   friend class __tree_const_iterator;
 };
 
-template <class _Key, class _Tp, class _Compare, class _Allocator>
+template <class _Key, class _Tp, class _Compare = less<_Key>, class _Allocator = allocator<pair<const _Key, _Tp> > >
+class multimap;
+
+template <class _Key, class _Tp, class _Compare = less<_Key>, class _Allocator = allocator<pair<const _Key, _Tp> > >
 class map {
 public:
   // types:
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index b07a153eacfae..c431c0cb407f3 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -1607,7 +1607,6 @@ module std [system] {
   }
 
   module map {
-    module fwd { header "__fwd/map.h" }
     header "map"
     export *
     export std.iterator.reverse_iterator
@@ -1974,7 +1973,6 @@ module std [system] {
   }
 
   module set {
-    module fwd { header "__fwd/set.h" }
     header "set"
     export *
     export std.iterator.reverse_iterator
diff --git a/libcxx/include/set b/libcxx/include/set
index 342a5294c814f..c77345bc5dc1f 100644
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -522,7 +522,6 @@ erase_if(multiset<Key, Compare, Allocator>& c, Predicate pred);  // C++20
 #  include <__config>
 #  include <__functional/is_transparent.h>
 #  include <__functional/operations.h>
-#  include <__fwd/set.h>
 #  include <__iterator/erase_if_container.h>
 #  include <__iterator/iterator_traits.h>
 #  include <__iterator/ranges_iterator_traits.h>
@@ -570,7 +569,10 @@ _LIBCPP_PUSH_MACROS
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-template <class _Key, class _Compare, class _Allocator>
+template <class _Key, class _Compare = less<_Key>, class _Allocator = allocator<_Key> >
+class multiset;
+
+template <class _Key, class _Compare = less<_Key>, class _Allocator = allocator<_Key> >
 class set {
 public:
   // types: