LLVM  15.0.0git
AllocatorBase.h
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1 //===- AllocatorBase.h - Simple memory allocation abstraction ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 /// \file
9 ///
10 /// This file defines MallocAllocator. MallocAllocator conforms to the LLVM
11 /// "Allocator" concept which consists of an Allocate method accepting a size
12 /// and alignment, and a Deallocate accepting a pointer and size. Further, the
13 /// LLVM "Allocator" concept has overloads of Allocate and Deallocate for
14 /// setting size and alignment based on the final type. These overloads are
15 /// typically provided by a base class template \c AllocatorBase.
16 ///
17 //===----------------------------------------------------------------------===//
18 
19 #ifndef LLVM_SUPPORT_ALLOCATORBASE_H
20 #define LLVM_SUPPORT_ALLOCATORBASE_H
21 
22 #include "llvm/Support/Compiler.h"
23 #include "llvm/Support/MemAlloc.h"
24 #include <type_traits>
25 
26 namespace llvm {
27 
28 /// CRTP base class providing obvious overloads for the core \c
29 /// Allocate() methods of LLVM-style allocators.
30 ///
31 /// This base class both documents the full public interface exposed by all
32 /// LLVM-style allocators, and redirects all of the overloads to a single core
33 /// set of methods which the derived class must define.
34 template <typename DerivedT> class AllocatorBase {
35 public:
36  /// Allocate \a Size bytes of \a Alignment aligned memory. This method
37  /// must be implemented by \c DerivedT.
38  void *Allocate(size_t Size, size_t Alignment) {
39 #ifdef __clang__
40  static_assert(static_cast<void *(AllocatorBase::*)(size_t, size_t)>(
42  static_cast<void *(DerivedT::*)(size_t, size_t)>(
43  &DerivedT::Allocate),
44  "Class derives from AllocatorBase without implementing the "
45  "core Allocate(size_t, size_t) overload!");
46 #endif
47  return static_cast<DerivedT *>(this)->Allocate(Size, Alignment);
48  }
49 
50  /// Deallocate \a Ptr to \a Size bytes of memory allocated by this
51  /// allocator.
52  void Deallocate(const void *Ptr, size_t Size, size_t Alignment) {
53 #ifdef __clang__
54  static_assert(
55  static_cast<void (AllocatorBase::*)(const void *, size_t, size_t)>(
57  static_cast<void (DerivedT::*)(const void *, size_t, size_t)>(
58  &DerivedT::Deallocate),
59  "Class derives from AllocatorBase without implementing the "
60  "core Deallocate(void *) overload!");
61 #endif
62  return static_cast<DerivedT *>(this)->Deallocate(Ptr, Size, Alignment);
63  }
64 
65  // The rest of these methods are helpers that redirect to one of the above
66  // core methods.
67 
68  /// Allocate space for a sequence of objects without constructing them.
69  template <typename T> T *Allocate(size_t Num = 1) {
70  return static_cast<T *>(Allocate(Num * sizeof(T), alignof(T)));
71  }
72 
73  /// Deallocate space for a sequence of objects without constructing them.
74  template <typename T>
75  std::enable_if_t<!std::is_same<std::remove_cv_t<T>, void>::value, void>
76  Deallocate(T *Ptr, size_t Num = 1) {
77  Deallocate(static_cast<const void *>(Ptr), Num * sizeof(T), alignof(T));
78  }
79 };
80 
81 class MallocAllocator : public AllocatorBase<MallocAllocator> {
82 public:
83  void Reset() {}
84 
85  LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size, size_t Alignment) {
86  return allocate_buffer(Size, Alignment);
87  }
88 
89  // Pull in base class overloads.
91 
92  void Deallocate(const void *Ptr, size_t Size, size_t Alignment) {
93  deallocate_buffer(const_cast<void *>(Ptr), Size, Alignment);
94  }
95 
96  // Pull in base class overloads.
98 
99  void PrintStats() const {}
100 };
101 
102 } // namespace llvm
103 
104 #endif // LLVM_SUPPORT_ALLOCATORBASE_H
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::AllocatorBase::Allocate
void * Allocate(size_t Size, size_t Alignment)
Allocate Size bytes of Alignment aligned memory.
Definition: AllocatorBase.h:38
llvm::allocate_buffer
LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void * allocate_buffer(size_t Size, size_t Alignment)
Allocate a buffer of memory with the given size and alignment.
Definition: MemAlloc.cpp:15
llvm::AllocatorBase::Deallocate
std::enable_if_t<!std::is_same< std::remove_cv_t< T >, void >::value, void > Deallocate(T *Ptr, size_t Num=1)
Deallocate space for a sequence of objects without constructing them.
Definition: AllocatorBase.h:76
llvm::deallocate_buffer
void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment)
Deallocate a buffer of memory with the given size and alignment.
Definition: MemAlloc.cpp:24
T
#define T
Definition: Mips16ISelLowering.cpp:341
llvm::MallocAllocator::PrintStats
void PrintStats() const
Definition: AllocatorBase.h:99
llvm::AllocatorBase::Allocate
T * Allocate(size_t Num=1)
Allocate space for a sequence of objects without constructing them.
Definition: AllocatorBase.h:69
llvm::AllocatorBase::Deallocate
void Deallocate(const void *Ptr, size_t Size, size_t Alignment)
Deallocate Ptr to Size bytes of memory allocated by this allocator.
Definition: AllocatorBase.h:52
llvm::MallocAllocator::Deallocate
void Deallocate(const void *Ptr, size_t Size, size_t Alignment)
Definition: AllocatorBase.h:92
MemAlloc.h
LLVM_ATTRIBUTE_RETURNS_NONNULL
#define LLVM_ATTRIBUTE_RETURNS_NONNULL
Definition: Compiler.h:257
llvm::MallocAllocator::Reset
void Reset()
Definition: AllocatorBase.h:83
Compiler.h
llvm::MallocAllocator
Definition: AllocatorBase.h:81
llvm::AllocatorBase
CRTP base class providing obvious overloads for the core Allocate() methods of LLVM-style allocators.
Definition: AllocatorBase.h:34
llvm::MallocAllocator::Allocate
LLVM_ATTRIBUTE_RETURNS_NONNULL void * Allocate(size_t Size, size_t Alignment)
Definition: AllocatorBase.h:85