release/21.x: [libc++] Disable cv-qualified arithmetic hash specializations (#155786) #156054
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@ldionne What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-libcxx Author: None (llvmbot) ChangesBackport 8a65c4f Requested by: @philnik777 Full diff: https://github.com/llvm/llvm-project/pull/156054.diff 7 Files Affected:
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index 85758c671e1e0..9e9852de2a4c7 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -874,6 +874,7 @@ set(files
__type_traits/is_trivially_relocatable.h
__type_traits/is_unbounded_array.h
__type_traits/is_union.h
+ __type_traits/is_unqualified.h
__type_traits/is_unsigned.h
__type_traits/is_valid_expansion.h
__type_traits/is_void.h
diff --git a/libcxx/include/__functional/hash.h b/libcxx/include/__functional/hash.h
index 489a6f00b8a3d..83bbf1b5e26c3 100644
--- a/libcxx/include/__functional/hash.h
+++ b/libcxx/include/__functional/hash.h
@@ -21,6 +21,7 @@
#include <__type_traits/is_enum.h>
#include <__type_traits/is_floating_point.h>
#include <__type_traits/is_integral.h>
+#include <__type_traits/is_unqualified.h>
#include <__type_traits/underlying_type.h>
#include <__utility/pair.h>
#include <__utility/swap.h>
@@ -355,7 +356,8 @@ struct __hash_impl {
};
template <class _Tp>
-struct __hash_impl<_Tp, __enable_if_t<is_enum<_Tp>::value> > : __unary_function<_Tp, size_t> {
+struct __hash_impl<_Tp, __enable_if_t<is_enum<_Tp>::value && __is_unqualified_v<_Tp> > >
+ : __unary_function<_Tp, size_t> {
_LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {
using type = __underlying_type_t<_Tp>;
return hash<type>()(static_cast<type>(__v));
@@ -363,17 +365,21 @@ struct __hash_impl<_Tp, __enable_if_t<is_enum<_Tp>::value> > : __unary_function<
};
template <class _Tp>
-struct __hash_impl<_Tp, __enable_if_t<is_integral<_Tp>::value && (sizeof(_Tp) <= sizeof(size_t))> >
+struct __hash_impl<
+ _Tp,
+ __enable_if_t<is_integral<_Tp>::value && __is_unqualified_v<_Tp> && (sizeof(_Tp) <= sizeof(size_t))> >
: __unary_function<_Tp, size_t> {
_LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT { return static_cast<size_t>(__v); }
};
template <class _Tp>
-struct __hash_impl<_Tp, __enable_if_t<is_integral<_Tp>::value && (sizeof(_Tp) > sizeof(size_t))> >
+struct __hash_impl<_Tp,
+ __enable_if_t<is_integral<_Tp>::value && __is_unqualified_v<_Tp> && (sizeof(_Tp) > sizeof(size_t))> >
: __scalar_hash<_Tp> {};
template <class _Tp>
-struct __hash_impl<_Tp, __enable_if_t<is_floating_point<_Tp>::value> > : __scalar_hash<_Tp> {
+struct __hash_impl<_Tp, __enable_if_t<is_floating_point<_Tp>::value && __is_unqualified_v<_Tp> > >
+ : __scalar_hash<_Tp> {
_LIBCPP_HIDE_FROM_ABI size_t operator()(_Tp __v) const _NOEXCEPT {
// -0.0 and 0.0 should return same hash
if (__v == 0.0f)
diff --git a/libcxx/include/__type_traits/is_unqualified.h b/libcxx/include/__type_traits/is_unqualified.h
new file mode 100644
index 0000000000000..7970b3611601f
--- /dev/null
+++ b/libcxx/include/__type_traits/is_unqualified.h
@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___TYPE_TRAITS_IS_UNQUALIFIED_H
+#define _LIBCPP___TYPE_TRAITS_IS_UNQUALIFIED_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+inline const bool __is_unqualified_v = __is_same(_Tp, __remove_cvref(_Tp));
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___TYPE_TRAITS_IS_UNQUALIFIED_H
diff --git a/libcxx/include/module.modulemap.in b/libcxx/include/module.modulemap.in
index 53f10ab8a92a5..4509dc20c6e65 100644
--- a/libcxx/include/module.modulemap.in
+++ b/libcxx/include/module.modulemap.in
@@ -336,6 +336,7 @@ module std_core [system] {
header "__type_traits/is_union.h"
export std_core.type_traits.integral_constant
}
+ module is_unqualified { header "__type_traits/is_unqualified.h" }
module is_unsigned {
header "__type_traits/is_unsigned.h"
export std_core.type_traits.integral_constant
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
index fd1fbe5f113ba..05a19329f909a 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
@@ -21,6 +21,10 @@
#include "test_macros.h"
+#if TEST_STD_VER >= 11
+# include "poisoned_hash_helper.h"
+#endif
+
enum class Colors { red, orange, yellow, green, blue, indigo, violet };
enum class Cardinals { zero, one, two, three, five=5 };
enum class LongColors : short { red, orange, yellow, green, blue, indigo, violet };
@@ -33,6 +37,12 @@ template <class T>
void
test()
{
+#if TEST_STD_VER >= 11
+ test_hash_disabled<const T>();
+ test_hash_disabled<volatile T>();
+ test_hash_disabled<const volatile T>();
+#endif
+
typedef std::hash<T> H;
#if TEST_STD_VER <= 17
static_assert((std::is_same<typename H::argument_type, T>::value), "");
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
index b8f85e193dc8f..f6c31d068b231 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
@@ -27,10 +27,20 @@
#include "test_macros.h"
+#if TEST_STD_VER >= 11
+# include "poisoned_hash_helper.h"
+#endif
+
template <class T>
void
test()
{
+#if TEST_STD_VER >= 11
+ test_hash_disabled<const T>();
+ test_hash_disabled<volatile T>();
+ test_hash_disabled<const volatile T>();
+#endif
+
typedef std::hash<T> H;
#if TEST_STD_VER <= 17
static_assert((std::is_same<typename H::argument_type, T>::value), "");
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
index 14af7093c1e36..c798b3aa77ea5 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
@@ -26,10 +26,20 @@
#include "test_macros.h"
+#if TEST_STD_VER >= 11
+# include "poisoned_hash_helper.h"
+#endif
+
template <class T>
void
test()
{
+#if TEST_STD_VER >= 11
+ test_hash_disabled<const T>();
+ test_hash_disabled<volatile T>();
+ test_hash_disabled<const volatile T>();
+#endif
+
typedef std::hash<T> H;
#if TEST_STD_VER <= 17
static_assert((std::is_same<typename H::argument_type, T>::value), "");
|
var-const
approved these changes
Aug 30, 2025
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@philnik777 (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
…55786) llvm#140407 accidentally enabled `hash` for cv-qualified types. This patch disables these specializations again. (cherry picked from commit 8a65c4f)
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Backport 8a65c4f
Requested by: @philnik777