Upgrade to 2022-era LLVM LIBCXX

2025-06-02 10:42:27 +00:00 · 2024-05-27 02:12:27 -07:00 · 2024-05-27 02:12:27 -07:00 · 8e68384e15
commit 8e68384e15
parent 2f4ca71f26
2078 changed files with 165657 additions and 65010 deletions
--- a/third_party/libcxx/__algorithm/sift_down.h
+++ b/third_party/libcxx/__algorithm/sift_down.h
@ -0,0 +1,114 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___ALGORITHM_SIFT_DOWN_H
+#define _LIBCPP___ALGORITHM_SIFT_DOWN_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__assert>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
+__sift_down(_RandomAccessIterator __first, _Compare&& __comp,
+            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+            _RandomAccessIterator __start)
+{
+    using _Ops = _IterOps<_AlgPolicy>;
+
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    // left-child of __start is at 2 * __start + 1
+    // right-child of __start is at 2 * __start + 2
+    difference_type __child = __start - __first;
+
+    if (__len < 2 || (__len - 2) / 2 < __child)
+        return;
+
+    __child = 2 * __child + 1;
+    _RandomAccessIterator __child_i = __first + __child;
+
+    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + difference_type(1)))) {
+        // right-child exists and is greater than left-child
+        ++__child_i;
+        ++__child;
+    }
+
+    // check if we are in heap-order
+    if (__comp(*__child_i, *__start))
+        // we are, __start is larger than its largest child
+        return;
+
+    value_type __top(_Ops::__iter_move(__start));
+    do
+    {
+        // we are not in heap-order, swap the parent with its largest child
+        *__start = _Ops::__iter_move(__child_i);
+        __start = __child_i;
+
+        if ((__len - 2) / 2 < __child)
+            break;
+
+        // recompute the child based off of the updated parent
+        __child = 2 * __child + 1;
+        __child_i = __first + __child;
+
+        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + difference_type(1)))) {
+            // right-child exists and is greater than left-child
+            ++__child_i;
+            ++__child;
+        }
+
+        // check if we are in heap-order
+    } while (!__comp(*__child_i, __top));
+    *__start = _VSTD::move(__top);
+}
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _RandomAccessIterator
+__floyd_sift_down(_RandomAccessIterator __first, _Compare&& __comp,
+                  typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
+    _LIBCPP_ASSERT(__len >= 2, "shouldn't be called unless __len >= 2");
+
+    _RandomAccessIterator __hole = __first;
+    _RandomAccessIterator __child_i = __first;
+    difference_type __child = 0;
+
+    while (true) {
+        __child_i += difference_type(__child + 1);
+        __child = 2 * __child + 1;
+
+        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + difference_type(1)))) {
+            // right-child exists and is greater than left-child
+            ++__child_i;
+            ++__child;
+        }
+
+        // swap __hole with its largest child
+        *__hole = _IterOps<_AlgPolicy>::__iter_move(__child_i);
+        __hole = __child_i;
+
+        // if __hole is now a leaf, we're done
+        if (__child > (__len - 2) / 2)
+            return __hole;
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SIFT_DOWN_H