[committed] libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
Tested x86_64-linux. Pushed to trunk. -- >8 -- As noted in PR c++/111512, GCC does ADL for __builtin_memcpy if it is unqualified, which can cause errors for template argument types which cannot be completed. Casting the memcpy arguments to void* prevents ADL from considering the problem type. libstdc++-v3/ChangeLog: PR libstdc++/111511 PR c++/111512 * include/std/array (to_array): Cast memcpy arguments to void*. * testsuite/23_containers/array/creation/111512.cc: New test. --- libstdc++-v3/include/std/array| 4 ++-- .../23_containers/array/creation/111512.cc| 24 +++ 2 files changed, 26 insertions(+), 2 deletions(-) create mode 100644 libstdc++-v3/testsuite/23_containers/array/creation/111512.cc diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array index 0e32d7b52d0..c4d534c3a34 100644 --- a/libstdc++-v3/include/std/array +++ b/libstdc++-v3/include/std/array @@ -432,7 +432,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { array, _Nm> __arr; if (!__is_constant_evaluated() && _Nm != 0) - __builtin_memcpy(__arr.data(), __a, sizeof(__a)); + __builtin_memcpy((void*)__arr.data(), (void*)__a, sizeof(__a)); else for (size_t __i = 0; __i < _Nm; ++__i) __arr._M_elems[__i] = __a[__i]; @@ -461,7 +461,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION { array, _Nm> __arr; if (!__is_constant_evaluated() && _Nm != 0) - __builtin_memcpy(__arr.data(), __a, sizeof(__a)); + __builtin_memcpy((void*)__arr.data(), (void*)__a, sizeof(__a)); else for (size_t __i = 0; __i < _Nm; ++__i) __arr._M_elems[__i] = __a[__i]; diff --git a/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc b/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc new file mode 100644 index 000..b0f25a62153 --- /dev/null +++ b/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc @@ -0,0 +1,24 @@ +// { dg-do compile { target c++20 } } + +// Bug libstdc++/111511 - Incorrect ADL in std::to_array in GCC 11/12/13 +// Bug c++/111512 - GCC's __builtin_memcpy can trigger ADL + +#include +#include + +struct incomplete; + +template +struct holder { +T t; // { dg-bogus "'holder::t' has incomplete type" } +}; + +// A complete type that cannot be used as an associated type for ADL. +using adl_bomb = holder*; + +int main() +{ +adl_bomb a[1]{}; +(void) std::to_array(a); +(void) std::to_array(std::move(a)); +} -- 2.41.0
[committed] libstdc++: Prevent unwanted ADL in std::to_array [PR111512]
This is the fix for the release branches, where std::to_array is implemented differently. Tested x86_64-linux. Pushed to gcc-13 and gcc-12. Will push to gcc-11 after testing. -- >8 -- Qualify the calls to the __to_array helper to prevent ADL, so we don't try to complete associated classes. libstdc++-v3/ChangeLog: PR libstdc++/111511 PR c++/111512 * include/std/array (to_array): Qualify calls to __to_array. * testsuite/23_containers/array/creation/111512.cc: New test. (cherry picked from commit 77cf3773021b0a20d89623e09d620747a05588ec) --- libstdc++-v3/include/std/array| 4 +-- .../23_containers/array/creation/111512.cc| 25 +++ 2 files changed, 27 insertions(+), 2 deletions(-) create mode 100644 libstdc++-v3/testsuite/23_containers/array/creation/111512.cc diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array index 70280c1beeb..97cca454ef9 100644 --- a/libstdc++-v3/include/std/array +++ b/libstdc++-v3/include/std/array @@ -436,7 +436,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION static_assert(!is_array_v<_Tp>); static_assert(is_constructible_v<_Tp, _Tp&>); if constexpr (is_constructible_v<_Tp, _Tp&>) - return __to_array(__a, make_index_sequence<_Nm>{}); + return std::__to_array(__a, make_index_sequence<_Nm>{}); __builtin_unreachable(); // FIXME: see PR c++/91388 } @@ -449,7 +449,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION static_assert(!is_array_v<_Tp>); static_assert(is_move_constructible_v<_Tp>); if constexpr (is_move_constructible_v<_Tp>) - return __to_array<1>(__a, make_index_sequence<_Nm>{}); + return std::__to_array<1>(__a, make_index_sequence<_Nm>{}); __builtin_unreachable(); // FIXME: see PR c++/91388 } #endif // C++20 diff --git a/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc b/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc new file mode 100644 index 000..f510480ae4b --- /dev/null +++ b/libstdc++-v3/testsuite/23_containers/array/creation/111512.cc @@ -0,0 +1,25 @@ +// { dg-options "-std=gnu++20" } +// { dg-do compile { target c++20 } } + +// Bug libstdc++/111511 - Incorrect ADL in std::to_array in GCC 11/12/13 +// Bug c++/111512 - GCC's __builtin_memcpy can trigger ADL + +#include +#include + +struct incomplete; + +template +struct holder { +T t; // { dg-bogus "'holder::t' has incomplete type" } +}; + +// A complete type that cannot be used as an associated type for ADL. +using adl_bomb = holder*; + +int main() +{ +adl_bomb a[1]{}; +(void) std::to_array(a); +(void) std::to_array(std::move(a)); +} -- 2.41.0