[gcc(refs/vendors/ibm/heads/perf)] libstdc++: enable_view has false positives (LWG 3326)
Jiu Fu Guo
guojiufu@gcc.gnu.org
Thu Mar 19 05:48:49 GMT 2020
https://gcc.gnu.org/g:3841739c29a54c0141c3156cdd47891c258b2b88
commit 3841739c29a54c0141c3156cdd47891c258b2b88
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon Feb 24 11:45:20 2020 +0000
libstdc++: enable_view has false positives (LWG 3326)
* include/std/ranges (__deep_const_range, __enable_view_impl): Remove.
(ranges::enable_view): Simplify (LWG 3326).
* include/bits/range_access.h (ranges::enable_view): Declare.
* include/bits/regex.h (__enable_view_impl): Remove partial
specialization.
* include/bits/stl_multiset.h (__enable_view_impl): Likewise.
* include/bits/stl_set.h (__enable_view_impl): Likewise.
* include/bits/unordered_set.h (__enable_view_impl): Likewise.
* include/debug/multiset.h (__enable_view_impl): Likewise.
* include/debug/set.h (__enable_view_impl): Likewise.
* include/debug/unordered_set (__enable_view_impl): Likewise.
* include/experimental/string_view (ranges::enable_view): Define
partial specialization.
* include/std/span (ranges::enable_view): Likewise.
* include/std/string_view (ranges::enable_view): Likewise.
* testsuite/std/ranges/view.cc: Check satisfaction of updated concept.
Diff:
---
libstdc++-v3/ChangeLog | 19 +++++++++++++++++++
libstdc++-v3/include/bits/range_access.h | 3 +++
libstdc++-v3/include/bits/regex.h | 10 ----------
libstdc++-v3/include/bits/stl_multiset.h | 11 -----------
libstdc++-v3/include/bits/stl_set.h | 9 ---------
libstdc++-v3/include/bits/unordered_set.h | 15 ---------------
libstdc++-v3/include/debug/multiset.h | 13 -------------
libstdc++-v3/include/debug/set.h | 12 ------------
libstdc++-v3/include/debug/unordered_set | 16 ----------------
libstdc++-v3/include/experimental/string_view | 6 +++++-
libstdc++-v3/include/std/ranges | 19 +------------------
libstdc++-v3/include/std/span | 7 ++++++-
libstdc++-v3/include/std/string_view | 6 +++++-
libstdc++-v3/testsuite/std/ranges/view.cc | 12 +++++++++++-
14 files changed, 50 insertions(+), 108 deletions(-)
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 7e065ef3e1d..457afdbadc8 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,22 @@
+2020-02-24 Jonathan Wakely <jwakely@redhat.com>
+
+ * include/std/ranges (__deep_const_range, __enable_view_impl): Remove.
+ (ranges::enable_view): Simplify (LWG 3326).
+ * include/bits/range_access.h (ranges::enable_view): Declare.
+ * include/bits/regex.h (__enable_view_impl): Remove partial
+ specialization.
+ * include/bits/stl_multiset.h (__enable_view_impl): Likewise.
+ * include/bits/stl_set.h (__enable_view_impl): Likewise.
+ * include/bits/unordered_set.h (__enable_view_impl): Likewise.
+ * include/debug/multiset.h (__enable_view_impl): Likewise.
+ * include/debug/set.h (__enable_view_impl): Likewise.
+ * include/debug/unordered_set (__enable_view_impl): Likewise.
+ * include/experimental/string_view (ranges::enable_view): Define
+ partial specialization.
+ * include/std/span (ranges::enable_view): Likewise.
+ * include/std/string_view (ranges::enable_view): Likewise.
+ * testsuite/std/ranges/view.cc: Check satisfaction of updated concept.
+
2020-02-21 Jonathan Wakely <jwakely@redhat.com>
* include/std/optional (operator<=>(optional<T>, optional<U>))
diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h
index eb91ade35ff..8b276fd6625 100644
--- a/libstdc++-v3/include/bits/range_access.h
+++ b/libstdc++-v3/include/bits/range_access.h
@@ -346,6 +346,9 @@ namespace ranges
template<typename _Tp>
inline constexpr bool enable_borrowed_range = false;
+ template<typename _Tp>
+ extern const bool enable_view;
+
namespace __detail
{
template<integral _Tp>
diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index 3307e1c917c..dcae83eea4e 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -2058,16 +2058,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
_GLIBCXX_END_NAMESPACE_CXX11
-#if __cplusplus > 201703L
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Bi_iter, typename _Alloc>
- inline constexpr bool __enable_view_impl<match_results<_Bi_iter, _Alloc>>
- = false;
-} // namespace ranges::__detail
-#endif // C++20
-
// [28.11.2] Function template regex_match
/**
* @name Matching, Searching, and Replacing
diff --git a/libstdc++-v3/include/bits/stl_multiset.h b/libstdc++-v3/include/bits/stl_multiset.h
index b8b82912c91..ab62df1e508 100644
--- a/libstdc++-v3/include/bits/stl_multiset.h
+++ b/libstdc++-v3/include/bits/stl_multiset.h
@@ -1038,17 +1038,6 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
_S_get_tree(_GLIBCXX_STD_C::multiset<_Val, _Cmp2, _Alloc>& __set)
{ return __set._M_t; }
};
-
-#if __cplusplus > 201703L
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Key, typename _Compare, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<_GLIBCXX_STD_C::multiset<_Key, _Compare, _Alloc>>
- = false;
-} // namespace ranges::__detail
-#endif // C++20
#endif // C++17
_GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/include/bits/stl_set.h b/libstdc++-v3/include/bits/stl_set.h
index 5f3e78dc470..4f8d631bb3b 100644
--- a/libstdc++-v3/include/bits/stl_set.h
+++ b/libstdc++-v3/include/bits/stl_set.h
@@ -1051,15 +1051,6 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
_S_get_tree(_GLIBCXX_STD_C::multiset<_Val, _Cmp2, _Alloc>& __set)
{ return __set._M_t; }
};
-#if __cplusplus > 201703L
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Key, typename _Compare, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<_GLIBCXX_STD_C::set<_Key, _Compare, _Alloc>> = false;
-} // namespace ranges::__detail
-#endif // C++20
#endif // C++17
_GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/include/bits/unordered_set.h b/libstdc++-v3/include/bits/unordered_set.h
index 824eedbae3e..9c2cd45be9c 100644
--- a/libstdc++-v3/include/bits/unordered_set.h
+++ b/libstdc++-v3/include/bits/unordered_set.h
@@ -1771,21 +1771,6 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
_S_get_table(unordered_multiset<_Val, _Hash2, _Eq2, _Alloc>& __set)
{ return __set._M_h; }
};
-
-#if __cplusplus > 201703L
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Val, typename _Hash, typename _Eq, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<_GLIBCXX_STD_C::unordered_set<_Val, _Hash, _Eq,
- _Alloc>> = false;
- template<typename _Val, typename _Hash, typename _Eq, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<_GLIBCXX_STD_C::unordered_multiset<_Val, _Hash, _Eq,
- _Alloc>> = false;
-} // namespace ranges::__detail
-#endif // C++20
#endif // C++17
_GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/include/debug/multiset.h b/libstdc++-v3/include/debug/multiset.h
index f5b974ccdc4..fcbba339478 100644
--- a/libstdc++-v3/include/debug/multiset.h
+++ b/libstdc++-v3/include/debug/multiset.h
@@ -630,19 +630,6 @@ namespace __debug
{ return __x.swap(__y); }
} // namespace __debug
-
-#if __cplusplus > 201703L
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Key, typename _Compare, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<std::__debug::multiset<_Key, _Compare, _Alloc>>
- = false;
-} // namespace ranges::__detail
-_GLIBCXX_END_NAMESPACE_VERSION
-#endif // C++20
} // namespace std
#endif
diff --git a/libstdc++-v3/include/debug/set.h b/libstdc++-v3/include/debug/set.h
index f3f90476a48..093ff129f3e 100644
--- a/libstdc++-v3/include/debug/set.h
+++ b/libstdc++-v3/include/debug/set.h
@@ -641,18 +641,6 @@ namespace __debug
{ return __x.swap(__y); }
} // namespace __debug
-
-#if __cplusplus > 201703L
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Key, typename _Compare, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<std::__debug::set<_Key, _Compare, _Alloc>> = false;
-} // namespace ranges::__detail
-_GLIBCXX_END_NAMESPACE_VERSION
-#endif // C++20
} // namespace std
#endif
diff --git a/libstdc++-v3/include/debug/unordered_set b/libstdc++-v3/include/debug/unordered_set
index 040ae7f2ad4..9941bbe1c24 100644
--- a/libstdc++-v3/include/debug/unordered_set
+++ b/libstdc++-v3/include/debug/unordered_set
@@ -1183,22 +1183,6 @@ namespace __debug
{ return !(__x == __y); }
} // namespace __debug
-#if __cplusplus > 201703L
-_GLIBCXX_BEGIN_NAMESPACE_VERSION
-namespace ranges::__detail
-{
- template<typename _Tp> extern inline const bool __enable_view_impl;
- template<typename _Val, typename _Hash, typename _Eq, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<std::__debug::unordered_set<_Val, _Hash, _Eq, _Alloc>>
- = false;
- template<typename _Val, typename _Hash, typename _Eq, typename _Alloc>
- inline constexpr bool
- __enable_view_impl<std::__debug::unordered_multiset<_Val, _Hash, _Eq,
- _Alloc>> = false;
-} // namespace ranges::__detail
-_GLIBCXX_END_NAMESPACE_VERSION
-#endif // C++20
} // namespace std
#endif // C++11
diff --git a/libstdc++-v3/include/experimental/string_view b/libstdc++-v3/include/experimental/string_view
index 439650154ae..629db577c29 100644
--- a/libstdc++-v3/include/experimental/string_view
+++ b/libstdc++-v3/include/experimental/string_view
@@ -694,12 +694,16 @@ namespace experimental
#if __cpp_lib_concepts
namespace ranges
{
- template<typename> extern inline const bool enable_borrowed_range;
// Opt-in to borrowed_range concept
template<typename _CharT, typename _Traits>
inline constexpr bool
enable_borrowed_range<experimental::basic_string_view<_CharT, _Traits>>
= true;
+
+ // Opt-in to view concept
+ template<typename _CharT, typename _Traits>
+ inline constexpr bool
+ enable_view<experimental::basic_string_view<_CharT, _Traits>> = true;
}
#endif
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 8c925fa278b..0b2057c9661 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -65,25 +65,8 @@ namespace ranges
struct view_base { };
- namespace __detail
- {
- template<typename _Tp>
- concept __deep_const_range = range<_Tp> && range<const _Tp>
- && same_as<range_reference_t<_Tp>, range_reference_t<const _Tp>>;
-
- template<typename _Tp>
- inline constexpr bool __enable_view_impl
- = derived_from<_Tp, view_base> || (!__deep_const_range<_Tp>);
-
- template<typename _Tp>
- inline constexpr bool __enable_view_impl<std::initializer_list<_Tp>>
- = false;
-
- } // namespace __detail
-
template<typename _Tp>
- inline constexpr bool enable_view
- = __detail::__enable_view_impl<remove_cv_t<_Tp>>;
+ inline constexpr bool enable_view = derived_from<_Tp, view_base>;
template<typename _Tp>
concept view
diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span
index 16b09a1e50c..f658adb04cf 100644
--- a/libstdc++-v3/include/std/span
+++ b/libstdc++-v3/include/std/span
@@ -447,11 +447,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace ranges
{
- template<typename> extern inline const bool enable_borrowed_range;
// Opt-in to borrowed_range concept
template<typename _ElementType, size_t _Extent>
inline constexpr bool
enable_borrowed_range<span<_ElementType, _Extent>> = true;
+
+ // Opt-in to view concept
+ template<typename _ElementType, size_t _Extent>
+ inline constexpr bool
+ enable_view<span<_ElementType, _Extent>>
+ = _Extent == 0 || _Extent == dynamic_extent;
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
diff --git a/libstdc++-v3/include/std/string_view b/libstdc++-v3/include/std/string_view
index 16687f6c352..ea5d547e006 100644
--- a/libstdc++-v3/include/std/string_view
+++ b/libstdc++-v3/include/std/string_view
@@ -727,11 +727,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if __cpp_lib_concepts
namespace ranges
{
- template<typename> extern inline const bool enable_borrowed_range;
// Opt-in to borrowed_range concept
template<typename _CharT, typename _Traits>
inline constexpr bool
enable_borrowed_range<basic_string_view<_CharT, _Traits>> = true;
+
+ // Opt-in to view concept
+ template<typename _CharT, typename _Traits>
+ inline constexpr bool
+ enable_view<basic_string_view<_CharT, _Traits>> = true;
}
#endif
_GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/testsuite/std/ranges/view.cc b/libstdc++-v3/testsuite/std/ranges/view.cc
index d76c8013c2c..72e8bcb50d7 100644
--- a/libstdc++-v3/testsuite/std/ranges/view.cc
+++ b/libstdc++-v3/testsuite/std/ranges/view.cc
@@ -19,13 +19,23 @@
// { dg-do compile { target c++2a } }
#include <ranges>
+#include <span>
+#include <string_view>
+#include <experimental/string_view>
+#include <vector>
#include <vector>
#include <set>
#include <unordered_set>
#include <regex>
#include <testsuite_iterators.h>
-static_assert(std::ranges::view<std::vector<int>>);
+static_assert(std::ranges::view<std::span<int>>);
+static_assert(std::ranges::view<std::span<int, 0>>);
+static_assert(!std::ranges::view<std::span<int, 1>>);
+static_assert(std::ranges::view<std::string_view>);
+static_assert(std::ranges::view<std::experimental::string_view>);
+
+static_assert(!std::ranges::view<std::vector<int>>);
static_assert(!std::ranges::view<const std::vector<int>>);
static_assert(!std::ranges::view<std::initializer_list<int>>);
static_assert(!std::ranges::view<const std::initializer_list<int>>);
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