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Diffstat (limited to 'llvm/include/llvm/Support/AllocatorBase.h')
-rw-r--r-- | llvm/include/llvm/Support/AllocatorBase.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/llvm/include/llvm/Support/AllocatorBase.h b/llvm/include/llvm/Support/AllocatorBase.h new file mode 100644 index 0000000000000..e5549d111622e --- /dev/null +++ b/llvm/include/llvm/Support/AllocatorBase.h @@ -0,0 +1,103 @@ +//===- AllocatorBase.h - Simple memory allocation abstraction ---*- C++ -*-===// +// +// 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 +// +//===----------------------------------------------------------------------===// +/// \file +/// +/// This file defines MallocAllocator. MallocAllocator conforms to the LLVM +/// "Allocator" concept which consists of an Allocate method accepting a size +/// and alignment, and a Deallocate accepting a pointer and size. Further, the +/// LLVM "Allocator" concept has overloads of Allocate and Deallocate for +/// setting size and alignment based on the final type. These overloads are +/// typically provided by a base class template \c AllocatorBase. +/// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_ALLOCATORBASE_H +#define LLVM_SUPPORT_ALLOCATORBASE_H + +#include "llvm/Support/Compiler.h" +#include "llvm/Support/MemAlloc.h" + +namespace llvm { + +/// CRTP base class providing obvious overloads for the core \c +/// Allocate() methods of LLVM-style allocators. +/// +/// This base class both documents the full public interface exposed by all +/// LLVM-style allocators, and redirects all of the overloads to a single core +/// set of methods which the derived class must define. +template <typename DerivedT> class AllocatorBase { +public: + /// Allocate \a Size bytes of \a Alignment aligned memory. This method + /// must be implemented by \c DerivedT. + void *Allocate(size_t Size, size_t Alignment) { +#ifdef __clang__ + static_assert(static_cast<void *(AllocatorBase::*)(size_t, size_t)>( + &AllocatorBase::Allocate) != + static_cast<void *(DerivedT::*)(size_t, size_t)>( + &DerivedT::Allocate), + "Class derives from AllocatorBase without implementing the " + "core Allocate(size_t, size_t) overload!"); +#endif + return static_cast<DerivedT *>(this)->Allocate(Size, Alignment); + } + + /// Deallocate \a Ptr to \a Size bytes of memory allocated by this + /// allocator. + void Deallocate(const void *Ptr, size_t Size, size_t Alignment) { +#ifdef __clang__ + static_assert( + static_cast<void (AllocatorBase::*)(const void *, size_t, size_t)>( + &AllocatorBase::Deallocate) != + static_cast<void (DerivedT::*)(const void *, size_t, size_t)>( + &DerivedT::Deallocate), + "Class derives from AllocatorBase without implementing the " + "core Deallocate(void *) overload!"); +#endif + return static_cast<DerivedT *>(this)->Deallocate(Ptr, Size, Alignment); + } + + // The rest of these methods are helpers that redirect to one of the above + // core methods. + + /// Allocate space for a sequence of objects without constructing them. + template <typename T> T *Allocate(size_t Num = 1) { + return static_cast<T *>(Allocate(Num * sizeof(T), alignof(T))); + } + + /// Deallocate space for a sequence of objects without constructing them. + template <typename T> + std::enable_if_t<!std::is_same<std::remove_cv_t<T>, void>::value, void> + Deallocate(T *Ptr, size_t Num = 1) { + Deallocate(static_cast<const void *>(Ptr), Num * sizeof(T), alignof(T)); + } +}; + +class MallocAllocator : public AllocatorBase<MallocAllocator> { +public: + void Reset() {} + + LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, size_t Alignment) { + return allocate_buffer(Size, Alignment); + } + + // Pull in base class overloads. + using AllocatorBase<MallocAllocator>::Allocate; + + void Deallocate(const void *Ptr, size_t Size, size_t Alignment) { + deallocate_buffer(const_cast<void *>(Ptr), Size, Alignment); + } + + // Pull in base class overloads. + using AllocatorBase<MallocAllocator>::Deallocate; + + void PrintStats() const {} +}; + +} // namespace llvm + +#endif // LLVM_SUPPORT_ALLOCATORBASE_H |