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[libcu++] Add resource_cast and dynamic_resource_cast #8272

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71b3128
Add resource_cast and dynamic_resource_cast
pciolkosz Apr 1, 2026
55fc45c
Fix format
pciolkosz Apr 2, 2026
98485f6
Review feedback
pciolkosz Apr 3, 2026
23e3fc2
Fix GCC < 11 and NVRTC build failures
pciolkosz Apr 3, 2026
f985388
Fix ClangCUDA: guard try/catch with NV_IF_TARGET
pciolkosz Apr 3, 2026
a49f8ca
Fix MSVC: guard test_iset_dynamic_cast with NVRTC check
pciolkosz Apr 3, 2026
91d3288
Fix: move test_iset_dynamic_cast call inside NV_IF_TARGET
pciolkosz Apr 3, 2026
f1d8e92
Fix MSVC: no preprocessor directives inside macro arguments
pciolkosz Apr 3, 2026
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164 changes: 163 additions & 1 deletion libcudacxx/include/cuda/__memory_resource/any_resource.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
// 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
// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

Expand Down Expand Up @@ -225,6 +225,10 @@ struct __with_try_get_property
}
};

// Tag type for constructing type-erased resource wrappers from their base __basic_any
struct __from_base_tag
{};

_CCCL_BEGIN_NAMESPACE_ABI_VER4_BUMP

template <class... _Properties>
Expand Down Expand Up @@ -255,6 +259,12 @@ struct _CCCL_DECLSPEC_EMPTY_BASES any_synchronous_resource

using default_queries = ::cuda::mr::properties_list<_Properties...>;

//! @cond
explicit any_synchronous_resource(__from_base_tag, __base&& __b) noexcept
: __base(::cuda::std::move(__b))
{}
//! @endcond

private:
using __base::interface;
};
Expand All @@ -274,6 +284,12 @@ struct _CCCL_DECLSPEC_EMPTY_BASES any_resource

using default_queries = ::cuda::mr::properties_list<_Properties...>;

//! @cond
explicit any_resource(__from_base_tag, __base&& __b) noexcept
: __base(::cuda::std::move(__b))
{}
//! @endcond

private:
template <class...>
friend struct any_synchronous_resource;
Expand Down Expand Up @@ -330,6 +346,12 @@ struct _CCCL_DECLSPEC_EMPTY_BASES synchronous_resource_ref

using default_queries = ::cuda::mr::properties_list<_Properties...>;

//! @cond
explicit synchronous_resource_ref(__from_base_tag, __base&& __b) noexcept
: __base(::cuda::std::move(__b))
{}
//! @endcond

private:
template <class...>
friend struct synchronous_resource_ref;
Expand Down Expand Up @@ -378,6 +400,12 @@ struct _CCCL_DECLSPEC_EMPTY_BASES resource_ref

using default_queries = ::cuda::mr::properties_list<_Properties...>;

//! @cond
explicit resource_ref(__from_base_tag, __base&& __b) noexcept
: __base(::cuda::std::move(__b))
{}
//! @endcond

private:
template <class...>
friend struct synchronous_resource_ref;
Expand Down Expand Up @@ -953,6 +981,140 @@ auto make_any_resource(_Args&&... __args) -> any_resource<_Properties...>
return any_resource<_Properties...>{::cuda::std::in_place_type<_Resource>, ::cuda::std::forward<_Args>(__args)...};
}

// ── resource_cast ───────────────────────────────────────────────────────────
//
// Extracts a pointer to the concrete resource type stored inside a type-erased
// resource wrapper (any_resource, any_synchronous_resource, resource_ref,
// synchronous_resource_ref). Returns nullptr if the stored type does not
// match _Tp.

//! @brief Extracts a pointer to the concrete resource type \c _Tp from a
//! type-erased resource wrapper.
//! @tparam _Tp The concrete resource type to extract.
//! @param __res Pointer to the type-erased resource wrapper.
//! @return A pointer to the stored object of type \c _Tp, or \c nullptr if
//! the stored type does not match \c _Tp.
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(any_resource<_Properties...>* __res) noexcept -> _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy resource_with<_Tp, _Properties...>");
// Use static_cast to the __basic_any base to work around GCC < 11 template argument deduction issues.
return ::cuda::__any_cast<_Tp>(static_cast<::cuda::__basic_any<__iasync_resource<_Properties...>>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(const any_resource<_Properties...>* __res) noexcept -> const _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<const ::cuda::__basic_any<__iasync_resource<_Properties...>>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(any_synchronous_resource<_Properties...>* __res) noexcept -> _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::synchronous_resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy synchronous_resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<::cuda::__basic_any<__iresource<_Properties...>>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(const any_synchronous_resource<_Properties...>* __res) noexcept
-> const _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::synchronous_resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy synchronous_resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<const ::cuda::__basic_any<__iresource<_Properties...>>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(resource_ref<_Properties...>* __res) noexcept -> _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<::cuda::__basic_any<__iasync_resource<_Properties...>&>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(const resource_ref<_Properties...>* __res) noexcept -> const _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<const ::cuda::__basic_any<__iasync_resource<_Properties...>&>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(synchronous_resource_ref<_Properties...>* __res) noexcept -> _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::synchronous_resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy synchronous_resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<::cuda::__basic_any<__iresource<_Properties...>&>*>(__res));
}

//! @overload
template <class _Tp, class... _Properties>
[[nodiscard]] _CCCL_HOST_API auto resource_cast(const synchronous_resource_ref<_Properties...>* __res) noexcept
-> const _Tp*
{
static_assert(::cuda::std::is_void_v<_Tp> || ::cuda::mr::synchronous_resource_with<_Tp, _Properties...>,
"_Tp must be void or satisfy synchronous_resource_with<_Tp, _Properties...>");
return ::cuda::__any_cast<_Tp>(static_cast<const ::cuda::__basic_any<__iresource<_Properties...>&>*>(__res));
}

// ── dynamic_resource_cast ───────────────────────────────────────────────────
//
// Dynamically casts between type-erased resource wrappers that have different
// property sets, using runtime information to validate the conversion.

//! @brief Dynamically casts a type-erased resource to a different property set.
//! @tparam _DstProperties The destination property types (deduced from the
//! destination resource type template argument).
//! @param __src The source resource to cast from.
//! @return A new type-erased resource wrapper with the destination properties.
//! @throws __bad_any_cast if the runtime type does not support the destination
//! interface.
template <class... _DstProperties, class... _SrcProperties>
[[nodiscard]] _CCCL_HOST_API auto dynamic_resource_cast(any_resource<_SrcProperties...>&& __src)
-> any_resource<_DstProperties...>
{
return any_resource<_DstProperties...>{
__from_base_tag{}, ::cuda::__dynamic_any_cast<__iasync_resource<_DstProperties...>>(::cuda::std::move(__src))};
}

//! @overload
template <class... _DstProperties, class... _SrcProperties>
[[nodiscard]] _CCCL_HOST_API auto dynamic_resource_cast(any_synchronous_resource<_SrcProperties...>&& __src)
-> any_synchronous_resource<_DstProperties...>
{
return any_synchronous_resource<_DstProperties...>{
__from_base_tag{}, ::cuda::__dynamic_any_cast<__iresource<_DstProperties...>>(::cuda::std::move(__src))};
}

//! @overload
template <class... _DstProperties, class... _SrcProperties>
[[nodiscard]] _CCCL_HOST_API auto dynamic_resource_cast(resource_ref<_SrcProperties...>* __src)
-> resource_ref<_DstProperties...>
{
return resource_ref<_DstProperties...>{
__from_base_tag{}, ::cuda::__dynamic_any_cast<__iasync_resource<_DstProperties...>&>(*__src)};
}

//! @overload
template <class... _DstProperties, class... _SrcProperties>
[[nodiscard]] _CCCL_HOST_API auto dynamic_resource_cast(synchronous_resource_ref<_SrcProperties...>* __src)
-> synchronous_resource_ref<_DstProperties...>
{
return synchronous_resource_ref<_DstProperties...>{
__from_base_tag{}, ::cuda::__dynamic_any_cast<__iresource<_DstProperties...>&>(*__src)};
}

_CCCL_END_NAMESPACE_CUDA_MR

# include <cuda/std/__cccl/epilogue.h>
Expand Down
12 changes: 8 additions & 4 deletions libcudacxx/include/cuda/__utility/__basic_any/rtti.h
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
// 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
// SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES.
// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

Expand Down Expand Up @@ -143,9 +143,13 @@ struct __rtti : __rtti_base
[[nodiscard]] _CCCL_API auto __query_interface(__iset_<_Interfaces...>) const noexcept
-> __vptr_for<__iset_<_Interfaces...>>
{
// TODO: find a way to check at runtime that the requested __iset_ is a subset
// of the interfaces in the vtable.
return static_cast<__vptr_for<__iset_<_Interfaces...>>>(this);
// Verify that every sub-interface in the requested set exists in the vtable.
// TODO: Can it be done in a more efficient way?
if ((__query_interface(_Interfaces{}) && ...))
{
return static_cast<__vptr_for<__iset_<_Interfaces...>>>(this);
}
return nullptr;
}

// Sequentially search the base_vptr_map for the requested interface by
Expand Down
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