[libc++] implement 'std::generator'

Author: xiaoyang-sde

libcxx/include/generator

@@ -206,11 +206,10 @@ private:
 
 public:
   _LIBCPP_HIDE_FROM_ABI __gen_promise_base() noexcept
-      : __data_{.__root =
-                    {
-                        .__value_ptr = nullptr,
-                        .__active    = coroutine_handle<__gen_promise_base>::from_promise(*this),
-                    }},
+      : __data_{.__root{
+            .__value_ptr{nullptr},
+            .__active{coroutine_handle<__gen_promise_base>::from_promise(*this)},
+        }},
         __tag_{false} {}
 
   _LIBCPP_HIDE_FROM_ABI ~__gen_promise_base() noexcept {
@@ -230,11 +229,12 @@ public:
     return {};
   }
 
-  _LIBCPP_HIDE_FROM_ABI auto yield_value(const remove_reference_t<_Yielded>& __value)
+  _LIBCPP_HIDE_FROM_ABI auto yield_value(const remove_reference_t<_Yielded>& __value) noexcept(
+      is_nothrow_constructible_v<remove_cvref_t<_Yielded>, const remove_reference_t<_Yielded>&>)
     requires is_rvalue_reference_v<_Yielded> &&
              constructible_from<remove_cvref_t<_Yielded>, const remove_reference_t<_Yielded>&>
   {
-    return __element_awaiter{.__value = __value};
+    return __element_awaiter{.__value{__value}};
   }
 
   template <class _Ref2, class _Val2, class _Allocator2, class _Unused>
@@ -304,7 +304,9 @@ public:
 
   _LIBCPP_HIDE_FROM_ABI void operator++(int) { ++*this; }
 
-  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool operator==(default_sentinel_t) const noexcept { return __coroutine_.done(); }
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI friend bool operator==(const __gen_iter& __iter, default_sentinel_t) noexcept {
+    return __iter.__coroutine_.done();
+  }
 
 private:
   coroutine_handle<__gen_promise_base<__gen_yielded<_Ref, _Val>>> __coroutine_;
@@ -363,7 +365,7 @@ private:
   _LIBCPP_HIDE_FROM_ABI explicit generator(coroutine_handle<promise_type> __coroutine) noexcept
       : __coroutine_{__coroutine} {}
 
-  coroutine_handle<promise_type> __coroutine_ = nullptr;
+  coroutine_handle<promise_type> __coroutine_;
 };
 
 _LIBCPP_END_NAMESPACE_STD

libcxx/test/libcxx/transitive_includes/cxx03.csv

@@ -370,6 +370,15 @@ future thread
 future type_traits
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx11.csv

@@ -372,6 +372,15 @@ future thread
 future type_traits
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx14.csv

@@ -375,6 +375,15 @@ future thread
 future type_traits
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx17.csv

@@ -375,6 +375,15 @@ future thread
 future type_traits
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx20.csv

@@ -386,6 +386,15 @@ future thread
 future type_traits
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx23.csv

@@ -259,6 +259,15 @@ future string
 future thread
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/libcxx/transitive_includes/cxx26.csv

@@ -282,6 +282,15 @@ future string
 future thread
 future typeinfo
 future version
+generator compare
+generator cstddef
+generator cstdint
+generator cstdlib
+generator cstring
+generator initializer_list
+generator limits
+generator new
+generator typeinfo
 initializer_list cstddef
 iomanip istream
 iomanip version

libcxx/test/std/ranges/coro.generator/generator.compile.pass.cpp

@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+
+// <generator>
+
+// template<class Ref, class V = void, class Allocator = void>
+//   class generator;
+
+#include <generator>
+
+#include <cassert>
+#include <concepts>
+#include <ranges>
+#include <type_traits>
+
+template <class G, class V, class R, class RR>
+constexpr bool conformance() {
+  static_assert(std::ranges::range<G>);
+  static_assert(std::ranges::view<G>);
+  static_assert(std::ranges::input_range<G>);
+  static_assert(!std::ranges::forward_range<G>);
+  static_assert(!std::ranges::borrowed_range<G>);
+
+  static_assert(std::same_as<std::ranges::range_value_t<G>, V>);
+  static_assert(std::same_as<std::ranges::range_reference_t<G>, R>);
+  static_assert(std::same_as<std::ranges::range_rvalue_reference_t<G>, RR>);
+
+  return true;
+}
+
+static_assert(conformance<std::generator<int>, int, int&&, int&&>());
+static_assert(conformance<std::generator<int, int>, int, int, int>());
+
+static_assert(conformance<std::generator<int&>, int, int&, int&&>());
+static_assert(conformance<std::generator<int&, int>, int, int&, int&&>());
+static_assert(conformance<std::generator<const int&>, int, const int&, const int&&>());
+static_assert(conformance<std::generator<const int&, int>, int, const int&, const int&&>());
+
+static_assert(conformance<std::generator<int&&>, int, int&&, int&&>());
+static_assert(conformance<std::generator<int&&, int>, int, int&&, int&&>());
+static_assert(conformance<std::generator<const int&&>, int, const int&&, const int&&>());
+static_assert(conformance<std::generator<const int&&, int>, int, const int&&, const int&&>());

libcxx/test/std/ranges/coro.generator/generator.pass.cpp

@@ -8,7 +8,10 @@
 
 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
 
-// std::generator
+// <generator>
+
+// template<class Ref, class V = void, class Allocator = void>
+//   class generator;
 
 #include <generator>
 
@@ -25,11 +28,24 @@ std::generator<int> fib() {
   }
 }
 
+std::generator<const int&> range_fib() {
+  co_yield std::ranges::elements_of(std::vector<int>{0, 1});
+  co_yield std::ranges::elements_of(std::vector<int>{1, 2});
+  co_yield std::ranges::elements_of(std::vector<int>{3, 5});
+  co_yield std::ranges::elements_of(std::vector<int>{5, 8});
+}
+
 bool test() {
   {
     std::vector<int> expected_fib_vec = {0, 1, 1, 2, 3};
-    auto fib_vec                      = fib() | std::views::take(5) | std::ranges::to<std::vector<int>>();
-    assert(fib_vec == expected_fib_vec);
+    {
+      auto fib_vec = fib() | std::views::take(5) | std::ranges::to<std::vector<int>>();
+      assert(fib_vec == expected_fib_vec);
+    }
+    {
+      auto fib_vec = range_fib() | std::views::take(5) | std::ranges::to<std::vector<int>>();
+      assert(fib_vec == expected_fib_vec);
+    }
   }
   return true;
 }