Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2014 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_COMPILER_OPTIMIZING_NODES_H_ |
| 18 | #define ART_COMPILER_OPTIMIZING_NODES_H_ |
| 19 | |
| 20 | #include "utils/allocation.h" |
Nicolas Geoffray | 0e33643 | 2014-02-26 18:24:38 +0000 | [diff] [blame^] | 21 | #include "utils/arena_bit_vector.h" |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 22 | #include "utils/growable_array.h" |
| 23 | |
| 24 | namespace art { |
| 25 | |
| 26 | class HBasicBlock; |
| 27 | class HInstruction; |
| 28 | class HGraphVisitor; |
| 29 | |
| 30 | static const int kDefaultNumberOfBlocks = 8; |
| 31 | static const int kDefaultNumberOfSuccessors = 2; |
| 32 | static const int kDefaultNumberOfPredecessors = 2; |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 33 | static const int kDefaultNumberOfBackEdges = 1; |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 34 | |
| 35 | // Control-flow graph of a method. Contains a list of basic blocks. |
| 36 | class HGraph : public ArenaObject { |
| 37 | public: |
| 38 | explicit HGraph(ArenaAllocator* arena) |
| 39 | : arena_(arena), |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 40 | blocks_(arena, kDefaultNumberOfBlocks), |
| 41 | dominator_order_(arena, kDefaultNumberOfBlocks) { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 42 | |
| 43 | ArenaAllocator* arena() const { return arena_; } |
| 44 | const GrowableArray<HBasicBlock*>* blocks() const { return &blocks_; } |
| 45 | |
| 46 | void AddBlock(HBasicBlock* block); |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 47 | void BuildDominatorTree(); |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 48 | |
| 49 | private: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 50 | HBasicBlock* FindCommonDominator(HBasicBlock* first, HBasicBlock* second) const; |
| 51 | void VisitBlockForDominatorTree(HBasicBlock* block, |
| 52 | HBasicBlock* predecessor, |
| 53 | GrowableArray<size_t>* visits); |
| 54 | void FindBackEdges(ArenaBitVector* visited) const; |
| 55 | void VisitBlockForBackEdges(HBasicBlock* block, |
| 56 | ArenaBitVector* visited, |
| 57 | ArenaBitVector* visiting) const; |
| 58 | void RemoveDeadBlocks(const ArenaBitVector& visited) const; |
| 59 | |
| 60 | HBasicBlock* GetEntryBlock() const { return blocks_.Get(0); } |
| 61 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 62 | ArenaAllocator* const arena_; |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 63 | |
| 64 | // List of blocks in insertion order. |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 65 | GrowableArray<HBasicBlock*> blocks_; |
| 66 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 67 | // List of blocks to perform a pre-order dominator tree traversal. |
| 68 | GrowableArray<HBasicBlock*> dominator_order_; |
| 69 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 70 | DISALLOW_COPY_AND_ASSIGN(HGraph); |
| 71 | }; |
| 72 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 73 | class HLoopInformation : public ArenaObject { |
| 74 | public: |
| 75 | HLoopInformation(HBasicBlock* header, HGraph* graph) |
| 76 | : header_(header), |
| 77 | back_edges_(graph->arena(), kDefaultNumberOfBackEdges) { } |
| 78 | |
| 79 | void AddBackEdge(HBasicBlock* back_edge) { |
| 80 | back_edges_.Add(back_edge); |
| 81 | } |
| 82 | |
| 83 | int NumberOfBackEdges() const { |
| 84 | return back_edges_.Size(); |
| 85 | } |
| 86 | |
| 87 | private: |
| 88 | HBasicBlock* header_; |
| 89 | GrowableArray<HBasicBlock*> back_edges_; |
| 90 | |
| 91 | DISALLOW_COPY_AND_ASSIGN(HLoopInformation); |
| 92 | }; |
| 93 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 94 | // A block in a method. Contains the list of instructions represented |
| 95 | // as a double linked list. Each block knows its predecessors and |
| 96 | // successors. |
| 97 | class HBasicBlock : public ArenaObject { |
| 98 | public: |
| 99 | explicit HBasicBlock(HGraph* graph) |
| 100 | : graph_(graph), |
| 101 | predecessors_(graph->arena(), kDefaultNumberOfPredecessors), |
| 102 | successors_(graph->arena(), kDefaultNumberOfSuccessors), |
| 103 | first_instruction_(nullptr), |
| 104 | last_instruction_(nullptr), |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 105 | loop_information_(nullptr), |
| 106 | dominator_(nullptr), |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 107 | block_id_(-1) { } |
| 108 | |
| 109 | const GrowableArray<HBasicBlock*>* predecessors() const { |
| 110 | return &predecessors_; |
| 111 | } |
| 112 | |
| 113 | const GrowableArray<HBasicBlock*>* successors() const { |
| 114 | return &successors_; |
| 115 | } |
| 116 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 117 | void AddBackEdge(HBasicBlock* back_edge) { |
| 118 | if (loop_information_ == nullptr) { |
| 119 | loop_information_ = new (graph_->arena()) HLoopInformation(this, graph_); |
| 120 | } |
| 121 | loop_information_->AddBackEdge(back_edge); |
| 122 | } |
| 123 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 124 | HGraph* graph() const { return graph_; } |
| 125 | |
| 126 | int block_id() const { return block_id_; } |
| 127 | void set_block_id(int id) { block_id_ = id; } |
| 128 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 129 | HBasicBlock* dominator() const { return dominator_; } |
| 130 | void set_dominator(HBasicBlock* dominator) { dominator_ = dominator; } |
| 131 | |
| 132 | int NumberOfBackEdges() const { |
| 133 | return loop_information_ == nullptr |
| 134 | ? 0 |
| 135 | : loop_information_->NumberOfBackEdges(); |
| 136 | } |
| 137 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 138 | HInstruction* first_instruction() const { return first_instruction_; } |
| 139 | HInstruction* last_instruction() const { return last_instruction_; } |
| 140 | |
| 141 | void AddSuccessor(HBasicBlock* block) { |
| 142 | successors_.Add(block); |
| 143 | block->predecessors_.Add(this); |
| 144 | } |
| 145 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 146 | void RemovePredecessor(HBasicBlock* block) { |
| 147 | predecessors_.Delete(block); |
| 148 | } |
| 149 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 150 | void AddInstruction(HInstruction* instruction); |
| 151 | |
| 152 | private: |
| 153 | HGraph* const graph_; |
| 154 | GrowableArray<HBasicBlock*> predecessors_; |
| 155 | GrowableArray<HBasicBlock*> successors_; |
| 156 | HInstruction* first_instruction_; |
| 157 | HInstruction* last_instruction_; |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 158 | HLoopInformation* loop_information_; |
| 159 | HBasicBlock* dominator_; |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 160 | int block_id_; |
| 161 | |
| 162 | DISALLOW_COPY_AND_ASSIGN(HBasicBlock); |
| 163 | }; |
| 164 | |
| 165 | #define FOR_EACH_INSTRUCTION(M) \ |
| 166 | M(Exit) \ |
| 167 | M(Goto) \ |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 168 | M(If) \ |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 169 | M(ReturnVoid) \ |
| 170 | |
| 171 | #define DECLARE_INSTRUCTION(type) \ |
| 172 | virtual void Accept(HGraphVisitor* visitor); \ |
| 173 | virtual const char* DebugName() const { return #type; } \ |
| 174 | |
| 175 | class HInstruction : public ArenaObject { |
| 176 | public: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 177 | HInstruction() : previous_(nullptr), next_(nullptr) { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 178 | virtual ~HInstruction() { } |
| 179 | |
| 180 | HInstruction* next() const { return next_; } |
| 181 | HInstruction* previous() const { return previous_; } |
| 182 | |
| 183 | virtual intptr_t InputCount() const = 0; |
| 184 | virtual HInstruction* InputAt(intptr_t i) const = 0; |
| 185 | |
| 186 | virtual void Accept(HGraphVisitor* visitor) = 0; |
| 187 | virtual const char* DebugName() const = 0; |
| 188 | |
| 189 | private: |
| 190 | HInstruction* previous_; |
| 191 | HInstruction* next_; |
| 192 | |
| 193 | friend class HBasicBlock; |
| 194 | |
| 195 | DISALLOW_COPY_AND_ASSIGN(HInstruction); |
| 196 | }; |
| 197 | |
| 198 | class HInstructionIterator : public ValueObject { |
| 199 | public: |
| 200 | explicit HInstructionIterator(HBasicBlock* block) |
| 201 | : instruction_(block->first_instruction()) { |
| 202 | next_ = Done() ? nullptr : instruction_->next(); |
| 203 | } |
| 204 | |
| 205 | inline bool Done() const { return instruction_ == nullptr; } |
| 206 | inline HInstruction* Current() { return instruction_; } |
| 207 | inline void Advance() { |
| 208 | instruction_ = next_; |
| 209 | next_ = Done() ? nullptr : instruction_->next(); |
| 210 | } |
| 211 | |
| 212 | private: |
| 213 | HInstruction* instruction_; |
| 214 | HInstruction* next_; |
| 215 | }; |
| 216 | |
| 217 | // An embedded container with N elements of type T. Used (with partial |
| 218 | // specialization for N=0) because embedded arrays cannot have size 0. |
| 219 | template<typename T, intptr_t N> |
| 220 | class EmbeddedArray { |
| 221 | public: |
| 222 | EmbeddedArray() : elements_() { } |
| 223 | |
| 224 | intptr_t length() const { return N; } |
| 225 | |
| 226 | const T& operator[](intptr_t i) const { |
| 227 | ASSERT(i < length()); |
| 228 | return elements_[i]; |
| 229 | } |
| 230 | |
| 231 | T& operator[](intptr_t i) { |
| 232 | ASSERT(i < length()); |
| 233 | return elements_[i]; |
| 234 | } |
| 235 | |
| 236 | const T& At(intptr_t i) const { |
| 237 | return (*this)[i]; |
| 238 | } |
| 239 | |
| 240 | void SetAt(intptr_t i, const T& val) { |
| 241 | (*this)[i] = val; |
| 242 | } |
| 243 | |
| 244 | private: |
| 245 | T elements_[N]; |
| 246 | }; |
| 247 | |
| 248 | template<typename T> |
| 249 | class EmbeddedArray<T, 0> { |
| 250 | public: |
| 251 | intptr_t length() const { return 0; } |
| 252 | const T& operator[](intptr_t i) const { |
| 253 | LOG(FATAL) << "Unreachable"; |
| 254 | static T sentinel = 0; |
| 255 | return sentinel; |
| 256 | } |
| 257 | T& operator[](intptr_t i) { |
| 258 | LOG(FATAL) << "Unreachable"; |
| 259 | static T sentinel = 0; |
| 260 | return sentinel; |
| 261 | } |
| 262 | }; |
| 263 | |
| 264 | template<intptr_t N> |
| 265 | class HTemplateInstruction: public HInstruction { |
| 266 | public: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 267 | HTemplateInstruction<N>() : inputs_() { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 268 | virtual ~HTemplateInstruction() { } |
| 269 | |
| 270 | virtual intptr_t InputCount() const { return N; } |
| 271 | virtual HInstruction* InputAt(intptr_t i) const { return inputs_[i]; } |
| 272 | |
| 273 | private: |
| 274 | EmbeddedArray<HInstruction*, N> inputs_; |
| 275 | }; |
| 276 | |
| 277 | // Represents dex's RETURN_VOID opcode. A HReturnVoid is a control flow |
| 278 | // instruction that branches to the exit block. |
| 279 | class HReturnVoid : public HTemplateInstruction<0> { |
| 280 | public: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 281 | HReturnVoid() { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 282 | |
| 283 | DECLARE_INSTRUCTION(ReturnVoid) |
| 284 | |
| 285 | private: |
| 286 | DISALLOW_COPY_AND_ASSIGN(HReturnVoid); |
| 287 | }; |
| 288 | |
| 289 | // The exit instruction is the only instruction of the exit block. |
| 290 | // Instructions aborting the method (HTrow and HReturn) must branch to the |
| 291 | // exit block. |
| 292 | class HExit : public HTemplateInstruction<0> { |
| 293 | public: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 294 | HExit() { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 295 | |
| 296 | DECLARE_INSTRUCTION(Exit) |
| 297 | |
| 298 | private: |
| 299 | DISALLOW_COPY_AND_ASSIGN(HExit); |
| 300 | }; |
| 301 | |
| 302 | // Jumps from one block to another. |
| 303 | class HGoto : public HTemplateInstruction<0> { |
| 304 | public: |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 305 | HGoto() { } |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 306 | |
| 307 | DECLARE_INSTRUCTION(Goto) |
| 308 | |
| 309 | private: |
| 310 | DISALLOW_COPY_AND_ASSIGN(HGoto); |
| 311 | }; |
| 312 | |
Nicolas Geoffray | be9a92a | 2014-02-25 14:22:56 +0000 | [diff] [blame] | 313 | // Conditional branch. A block ending with an HIf instruction must have |
| 314 | // two successors. |
| 315 | // TODO: Make it take an input. |
| 316 | class HIf : public HTemplateInstruction<0> { |
| 317 | public: |
| 318 | HIf() { } |
| 319 | |
| 320 | DECLARE_INSTRUCTION(If) |
| 321 | |
| 322 | private: |
| 323 | DISALLOW_COPY_AND_ASSIGN(HIf); |
| 324 | }; |
| 325 | |
Nicolas Geoffray | 818f210 | 2014-02-18 16:43:35 +0000 | [diff] [blame] | 326 | class HGraphVisitor : public ValueObject { |
| 327 | public: |
| 328 | explicit HGraphVisitor(HGraph* graph) : graph_(graph) { } |
| 329 | virtual ~HGraphVisitor() { } |
| 330 | |
| 331 | virtual void VisitInstruction(HInstruction* instruction) { } |
| 332 | virtual void VisitBasicBlock(HBasicBlock* block); |
| 333 | |
| 334 | void VisitInsertionOrder(); |
| 335 | |
| 336 | // Visit functions for instruction classes. |
| 337 | #define DECLARE_VISIT_INSTRUCTION(name) \ |
| 338 | virtual void Visit##name(H##name* instr) { VisitInstruction(instr); } |
| 339 | |
| 340 | FOR_EACH_INSTRUCTION(DECLARE_VISIT_INSTRUCTION) |
| 341 | |
| 342 | #undef DECLARE_VISIT_INSTRUCTION |
| 343 | |
| 344 | private: |
| 345 | HGraph* graph_; |
| 346 | |
| 347 | DISALLOW_COPY_AND_ASSIGN(HGraphVisitor); |
| 348 | }; |
| 349 | |
| 350 | } // namespace art |
| 351 | |
| 352 | #endif // ART_COMPILER_OPTIMIZING_NODES_H_ |