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" 20 #include "llvm/Support/ErrorHandling.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 __asan_unpoison_memory_region(Val, Size); 46 FreeList = FreeList->Next; 47 __msan_allocated_memory(Val, Size); 48 return Val; 49 } 50 51 void push(FreeNode *N) { 52 N->Next = FreeList; 53 FreeList = N; 54 __asan_poison_memory_region(N, Size); 55 } 56 57 public: 58 ~Recycler() { 59 // If this fails, either the callee has lost track of some allocation, 60 // or the callee isn't tracking allocations and should just call 61 // clear() before deleting the Recycler. 62 assert(!FreeList && "Non-empty recycler deleted!"); 63 } 64 65 /// clear - Release all the tracked allocations to the allocator. The 66 /// recycler must be free of any tracked allocations before being 67 /// deleted; calling clear is one way to ensure this. 68 template<class AllocatorType> 69 void clear(AllocatorType &Allocator) { 70 while (FreeList) { 71 T *t = reinterpret_cast<T *>(pop_val()); 72 Allocator.Deallocate(t); 73 } 74 } 75 76 /// Special case for BumpPtrAllocator which has an empty Deallocate() 77 /// function. 78 /// 79 /// There is no need to traverse the free list, pulling all the objects into 80 /// cache. 81 void clear(BumpPtrAllocator &) { FreeList = nullptr; } 82 83 template<class SubClass, class AllocatorType> 84 SubClass *Allocate(AllocatorType &Allocator) { 85 static_assert(alignof(SubClass) <= Align, 86 "Recycler allocation alignment is less than object align!"); 87 static_assert(sizeof(SubClass) <= Size, 88 "Recycler allocation size is less than object size!"); 89 return FreeList ? reinterpret_cast<SubClass *>(pop_val()) 90 : static_cast<SubClass *>(Allocator.Allocate(Size, Align)); 91 } 92 93 template<class AllocatorType> 94 T *Allocate(AllocatorType &Allocator) { 95 return Allocate<T>(Allocator); 96 } 97 98 template<class SubClass, class AllocatorType> 99 void Deallocate(AllocatorType & /*Allocator*/, SubClass* Element) { 100 push(reinterpret_cast<FreeNode *>(Element)); 101 } 102 103 void PrintStats(); 104 }; 105 106 template <class T, size_t Size, size_t Align> 107 void Recycler<T, Size, Align>::PrintStats() { 108 size_t S = 0; 109 for (auto *I = FreeList; I; I = I->Next) 110 ++S; 111 PrintRecyclerStats(Size, Align, S); 112 } 113 114 } 115 116 #endif 117
