1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_GC_ACCOUNTING_BITMAP_H_ 18 #define ART_RUNTIME_GC_ACCOUNTING_BITMAP_H_ 19 20 #include <limits.h> 21 #include <stdint.h> 22 #include <memory> 23 #include <set> 24 #include <vector> 25 26 #include "base/mutex.h" 27 #include "globals.h" 28 29 namespace art { 30 31 class MemMap; 32 33 namespace gc { 34 namespace accounting { 35 36 // TODO: Use this code to implement SpaceBitmap. 37 class Bitmap { 38 public: 39 // Create and initialize a bitmap with size num_bits. Storage is allocated with a MemMap. 40 static Bitmap* Create(const std::string& name, size_t num_bits); 41 42 // Initialize a space bitmap using the provided mem_map as the live bits. Takes ownership of the 43 // mem map. The address range covered starts at heap_begin and is of size equal to heap_capacity. 44 // Objects are kAlignement-aligned. 45 static Bitmap* CreateFromMemMap(MemMap* mem_map, size_t num_bits); 46 47 // offset is the difference from base to a index. BitIndexToWordIndex(uintptr_t offset)48 static ALWAYS_INLINE constexpr size_t BitIndexToWordIndex(uintptr_t offset) { 49 return offset / kBitsPerBitmapWord; 50 } 51 52 template<typename T> WordIndexToBitIndex(T word_index)53 static ALWAYS_INLINE constexpr T WordIndexToBitIndex(T word_index) { 54 return static_cast<T>(word_index * kBitsPerBitmapWord); 55 } 56 BitIndexToMask(uintptr_t bit_index)57 static ALWAYS_INLINE constexpr uintptr_t BitIndexToMask(uintptr_t bit_index) { 58 return static_cast<uintptr_t>(1) << (bit_index % kBitsPerBitmapWord); 59 } 60 SetBit(size_t bit_index)61 ALWAYS_INLINE bool SetBit(size_t bit_index) { 62 return ModifyBit<true>(bit_index); 63 } 64 ClearBit(size_t bit_index)65 ALWAYS_INLINE bool ClearBit(size_t bit_index) { 66 return ModifyBit<false>(bit_index); 67 } 68 69 ALWAYS_INLINE bool TestBit(size_t bit_index) const; 70 71 // Returns true if the bit_index was previously set. 72 ALWAYS_INLINE bool AtomicTestAndSetBit(size_t bit_index); 73 74 // Fill the bitmap with zeroes. Returns the bitmap's memory to the system as a side-effect. 75 void Clear(); 76 77 // Visit the all the set bits range [visit_begin, visit_end) where visit_begin and visit_end are 78 // bit indices visitor is called with the index of each set bit. 79 template <typename Visitor> 80 void VisitSetBits(uintptr_t visit_begin, size_t visit_end, const Visitor& visitor) const; 81 82 void CopyFrom(Bitmap* source_bitmap); 83 84 // Starting address of our internal storage. Begin()85 uintptr_t* Begin() { 86 return bitmap_begin_; 87 } 88 89 // Size of our bitmap in bits. BitmapSize()90 size_t BitmapSize() const { 91 return bitmap_size_; 92 } 93 94 // Check that a bit index is valid with a DCHECK. CheckValidBitIndex(size_t bit_index)95 ALWAYS_INLINE void CheckValidBitIndex(size_t bit_index) const { 96 DCHECK_LT(bit_index, BitmapSize()); 97 } 98 99 std::string Dump() const; 100 101 protected: 102 static constexpr size_t kBitsPerBitmapWord = sizeof(uintptr_t) * kBitsPerByte; 103 104 Bitmap(MemMap* mem_map, size_t bitmap_size); 105 ~Bitmap(); 106 107 // Allocate the mem-map for a bitmap based on how many bits are required. 108 static MemMap* AllocateMemMap(const std::string& name, size_t num_bits); 109 110 template<bool kSetBit> 111 ALWAYS_INLINE bool ModifyBit(uintptr_t bit_index); 112 113 // Backing storage for bitmap. 114 std::unique_ptr<MemMap> mem_map_; 115 116 // This bitmap itself, word sized for efficiency in scanning. 117 uintptr_t* const bitmap_begin_; 118 119 // Number of bits in the bitmap. 120 const size_t bitmap_size_; 121 122 private: 123 DISALLOW_IMPLICIT_CONSTRUCTORS(Bitmap); 124 }; 125 126 // One bit per kAlignment in range (start, end] 127 template<size_t kAlignment> 128 class MemoryRangeBitmap : public Bitmap { 129 public: 130 static MemoryRangeBitmap* Create(const std::string& name, uintptr_t cover_begin, 131 uintptr_t cover_end); 132 static MemoryRangeBitmap* CreateFromMemMap(MemMap* mem_map, uintptr_t cover_begin, 133 size_t num_bits); 134 135 // Beginning of the memory range that the bitmap covers. CoverBegin()136 ALWAYS_INLINE uintptr_t CoverBegin() const { 137 return cover_begin_; 138 } 139 140 // End of the memory range that the bitmap covers. CoverEnd()141 ALWAYS_INLINE uintptr_t CoverEnd() const { 142 return cover_end_; 143 } 144 145 // Return the address associated with a bit index. AddrFromBitIndex(size_t bit_index)146 ALWAYS_INLINE uintptr_t AddrFromBitIndex(size_t bit_index) const { 147 const uintptr_t addr = CoverBegin() + bit_index * kAlignment; 148 DCHECK_EQ(BitIndexFromAddr(addr), bit_index); 149 return addr; 150 } 151 152 // Return the bit index associated with an address . BitIndexFromAddr(uintptr_t addr)153 ALWAYS_INLINE uintptr_t BitIndexFromAddr(uintptr_t addr) const { 154 DCHECK(HasAddress(addr)) << CoverBegin() << " <= " << addr << " < " << CoverEnd(); 155 return (addr - CoverBegin()) / kAlignment; 156 } 157 HasAddress(const uintptr_t addr)158 ALWAYS_INLINE bool HasAddress(const uintptr_t addr) const { 159 return cover_begin_ <= addr && addr < cover_end_; 160 } 161 Set(uintptr_t addr)162 ALWAYS_INLINE bool Set(uintptr_t addr) { 163 return SetBit(BitIndexFromAddr(addr)); 164 } 165 Clear(size_t addr)166 ALWAYS_INLINE bool Clear(size_t addr) { 167 return ClearBit(BitIndexFromAddr(addr)); 168 } 169 Test(size_t addr)170 ALWAYS_INLINE bool Test(size_t addr) const { 171 return TestBit(BitIndexFromAddr(addr)); 172 } 173 174 // Returns true if the object was previously set. AtomicTestAndSet(size_t addr)175 ALWAYS_INLINE bool AtomicTestAndSet(size_t addr) { 176 return AtomicTestAndSetBit(BitIndexFromAddr(addr)); 177 } 178 179 private: MemoryRangeBitmap(MemMap * mem_map,uintptr_t begin,size_t num_bits)180 MemoryRangeBitmap(MemMap* mem_map, uintptr_t begin, size_t num_bits) 181 : Bitmap(mem_map, num_bits), cover_begin_(begin), cover_end_(begin + kAlignment * num_bits) { 182 } 183 184 uintptr_t const cover_begin_; 185 uintptr_t const cover_end_; 186 187 DISALLOW_IMPLICIT_CONSTRUCTORS(MemoryRangeBitmap); 188 }; 189 190 } // namespace accounting 191 } // namespace gc 192 } // namespace art 193 194 #endif // ART_RUNTIME_GC_ACCOUNTING_BITMAP_H_ 195