LLVM  4.0.0
Recycler.h
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1 //==- llvm/Support/Recycler.h - Recycling Allocator --------------*- C++ -*-==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the Recycler class template. See the doxygen comment for
11 // Recycler for more details.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_SUPPORT_RECYCLER_H
16 #define LLVM_SUPPORT_RECYCLER_H
17 
18 #include "llvm/ADT/ilist.h"
19 #include "llvm/Support/Allocator.h"
21 #include <cassert>
22 
23 namespace llvm {
24 
25 /// PrintRecyclingAllocatorStats - Helper for RecyclingAllocator for
26 /// printing statistics.
27 ///
28 void PrintRecyclerStats(size_t Size, size_t Align, size_t FreeListSize);
29 
30 /// Recycler - This class manages a linked-list of deallocated nodes
31 /// and facilitates reusing deallocated memory in place of allocating
32 /// new memory.
33 ///
34 template <class T, size_t Size = sizeof(T), size_t Align = alignof(T)>
35 class Recycler {
36  struct FreeNode {
37  FreeNode *Next;
38  };
39 
40  /// List of nodes that have deleted contents and are not in active use.
41  FreeNode *FreeList = nullptr;
42 
43  FreeNode *pop_val() {
44  auto *Val = FreeList;
45  FreeList = FreeList->Next;
46  return Val;
47  }
48 
49  void push(FreeNode *N) {
50  N->Next = FreeList;
51  FreeList = N;
52  }
53 
54 public:
56  // If this fails, either the callee has lost track of some allocation,
57  // or the callee isn't tracking allocations and should just call
58  // clear() before deleting the Recycler.
59  assert(!FreeList && "Non-empty recycler deleted!");
60  }
61 
62  /// clear - Release all the tracked allocations to the allocator. The
63  /// recycler must be free of any tracked allocations before being
64  /// deleted; calling clear is one way to ensure this.
65  template<class AllocatorType>
66  void clear(AllocatorType &Allocator) {
67  while (FreeList) {
68  T *t = reinterpret_cast<T *>(pop_val());
69  Allocator.Deallocate(t);
70  }
71  }
72 
73  /// Special case for BumpPtrAllocator which has an empty Deallocate()
74  /// function.
75  ///
76  /// There is no need to traverse the free list, pulling all the objects into
77  /// cache.
78  void clear(BumpPtrAllocator &) { FreeList = nullptr; }
79 
80  template<class SubClass, class AllocatorType>
81  SubClass *Allocate(AllocatorType &Allocator) {
82  static_assert(alignof(SubClass) <= Align,
83  "Recycler allocation alignment is less than object align!");
84  static_assert(sizeof(SubClass) <= Size,
85  "Recycler allocation size is less than object size!");
86  return FreeList ? reinterpret_cast<SubClass *>(pop_val())
87  : static_cast<SubClass *>(Allocator.Allocate(Size, Align));
88  }
89 
90  template<class AllocatorType>
91  T *Allocate(AllocatorType &Allocator) {
92  return Allocate<T>(Allocator);
93  }
94 
95  template<class SubClass, class AllocatorType>
96  void Deallocate(AllocatorType & /*Allocator*/, SubClass* Element) {
97  push(reinterpret_cast<FreeNode *>(Element));
98  }
99 
100  void PrintStats();
101 };
102 
103 template <class T, size_t Size, size_t Align>
105  size_t S = 0;
106  for (auto *I = FreeList; I; I = I->Next)
107  ++S;
108  PrintRecyclerStats(Size, Align, S);
109 }
110 
111 }
112 
113 #endif
void PrintStats()
Definition: Recycler.h:104
void PrintRecyclerStats(size_t Size, size_t Align, size_t FreeListSize)
PrintRecyclingAllocatorStats - Helper for RecyclingAllocator for printing statistics.
Definition: Allocator.cpp:32
This file defines the MallocAllocator and BumpPtrAllocator interfaces.
void clear(BumpPtrAllocator &)
Special case for BumpPtrAllocator which has an empty Deallocate() function.
Definition: Recycler.h:78
static F t[256]
SubClass * Allocate(AllocatorType &Allocator)
Definition: Recycler.h:81
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:138
Greedy Register Allocator
T * Allocate(AllocatorType &Allocator)
Definition: Recycler.h:91
Recycler - This class manages a linked-list of deallocated nodes and facilitates reusing deallocated ...
Definition: Recycler.h:35
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
void Deallocate(AllocatorType &, SubClass *Element)
Definition: Recycler.h:96
void clear(AllocatorType &Allocator)
clear - Release all the tracked allocations to the allocator.
Definition: Recycler.h:66
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())