08533a3ee8
We had three `utils::` namespaces, all with different "meaning" (host, device, hsa_utils). We should, when we can, keep "include/Shared" accessible from host and device, thus RefCountTy has been moved to a separate header. `hsa_utils` was introduced to make `utils::` less overloaded. And common functionality was de-duplicated, e.g., `utils::advance` and `utils::advanceVoidPtr` -> `utils:advancePtr`. Type punning now checks for the size of the result to make sure it matches the source type. No functional change was intended.
57 lines
1.7 KiB
C++
57 lines
1.7 KiB
C++
//===-- Shared/RefCnt.h - Helper to keep track of references --- C++ ------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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//===----------------------------------------------------------------------===//
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#ifndef OMPTARGET_SHARED_REF_CNT_H
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#define OMPTARGET_SHARED_REF_CNT_H
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#include <atomic>
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#include <cassert>
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#include <limits>
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#include <memory>
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namespace llvm {
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namespace omp {
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namespace target {
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/// Utility class for thread-safe reference counting. Any class that needs
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/// objects' reference counting can inherit from this entity or have it as a
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/// class data member.
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template <typename Ty = uint32_t,
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std::memory_order MemoryOrder = std::memory_order_relaxed>
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struct RefCountTy {
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/// Create a refcount object initialized to zero.
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RefCountTy() : Refs(0) {}
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~RefCountTy() { assert(Refs == 0 && "Destroying with non-zero refcount"); }
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/// Increase the reference count atomically.
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void increase() { Refs.fetch_add(1, MemoryOrder); }
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/// Decrease the reference count and return whether it became zero. Decreasing
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/// the counter in more units than it was previously increased results in
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/// undefined behavior.
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bool decrease() {
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Ty Prev = Refs.fetch_sub(1, MemoryOrder);
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assert(Prev > 0 && "Invalid refcount");
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return (Prev == 1);
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}
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Ty get() const { return Refs.load(MemoryOrder); }
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private:
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/// The atomic reference counter.
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std::atomic<Ty> Refs;
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};
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} // namespace target
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} // namespace omp
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} // namespace llvm
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#endif
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