MachineBasicBlock.h revision c7f6b8c5d40e17bf43fd3a1549d7d89c9da735e1
1//===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- 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// Collect the sequence of machine instructions for a basic block. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H 15#define LLVM_CODEGEN_MACHINEBASICBLOCK_H 16 17#include "llvm/CodeGen/MachineInstr.h" 18#include "llvm/ADT/GraphTraits.h" 19#include "llvm/Support/Streams.h" 20 21namespace llvm { 22 23class BasicBlock; 24class MachineFunction; 25 26template <> 27struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> { 28private: 29 mutable ilist_node<MachineInstr> Sentinel; 30 31 // this is only set by the MachineBasicBlock owning the LiveList 32 friend class MachineBasicBlock; 33 MachineBasicBlock* Parent; 34 35public: 36 MachineInstr *createSentinel() const { 37 return static_cast<MachineInstr*>(&Sentinel); 38 } 39 void destroySentinel(MachineInstr *) const {} 40 41 void addNodeToList(MachineInstr* N); 42 void removeNodeFromList(MachineInstr* N); 43 void transferNodesFromList(ilist_traits &SrcTraits, 44 ilist_iterator<MachineInstr> first, 45 ilist_iterator<MachineInstr> last); 46 void deleteNode(MachineInstr *N); 47private: 48 void createNode(const MachineInstr &); 49}; 50 51class MachineBasicBlock : public ilist_node<MachineBasicBlock> { 52 typedef ilist<MachineInstr> Instructions; 53 Instructions Insts; 54 const BasicBlock *BB; 55 int Number; 56 MachineFunction *xParent; 57 58 /// Predecessors/Successors - Keep track of the predecessor / successor 59 /// basicblocks. 60 std::vector<MachineBasicBlock *> Predecessors; 61 std::vector<MachineBasicBlock *> Successors; 62 63 /// LiveIns - Keep track of the physical registers that are livein of 64 /// the basicblock. 65 std::vector<unsigned> LiveIns; 66 67 /// Alignment - Alignment of the basic block. Zero if the basic block does 68 /// not need to be aligned. 69 unsigned Alignment; 70 71 /// IsLandingPad - Indicate that this basic block is entered via an 72 /// exception handler. 73 bool IsLandingPad; 74 75 // Intrusive list support 76 friend struct ilist_sentinel_traits<MachineBasicBlock>; 77 MachineBasicBlock() {} 78 79 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb); 80 81 ~MachineBasicBlock(); 82 83 // MachineBasicBlocks are allocated and owned by MachineFunction. 84 friend class MachineFunction; 85 86public: 87 /// getBasicBlock - Return the LLVM basic block that this instance 88 /// corresponded to originally. 89 /// 90 const BasicBlock *getBasicBlock() const { return BB; } 91 92 /// getParent - Return the MachineFunction containing this basic block. 93 /// 94 const MachineFunction *getParent() const { return xParent; } 95 MachineFunction *getParent() { return xParent; } 96 97 typedef Instructions::iterator iterator; 98 typedef Instructions::const_iterator const_iterator; 99 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 100 typedef std::reverse_iterator<iterator> reverse_iterator; 101 102 unsigned size() const { return (unsigned)Insts.size(); } 103 bool empty() const { return Insts.empty(); } 104 105 MachineInstr& front() { return Insts.front(); } 106 MachineInstr& back() { return Insts.back(); } 107 const MachineInstr& front() const { return Insts.front(); } 108 const MachineInstr& back() const { return Insts.back(); } 109 110 iterator begin() { return Insts.begin(); } 111 const_iterator begin() const { return Insts.begin(); } 112 iterator end() { return Insts.end(); } 113 const_iterator end() const { return Insts.end(); } 114 reverse_iterator rbegin() { return Insts.rbegin(); } 115 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 116 reverse_iterator rend () { return Insts.rend(); } 117 const_reverse_iterator rend () const { return Insts.rend(); } 118 119 // Machine-CFG iterators 120 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 121 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 122 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 123 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 124 typedef std::vector<MachineBasicBlock *>::reverse_iterator 125 pred_reverse_iterator; 126 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 127 const_pred_reverse_iterator; 128 typedef std::vector<MachineBasicBlock *>::reverse_iterator 129 succ_reverse_iterator; 130 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 131 const_succ_reverse_iterator; 132 133 pred_iterator pred_begin() { return Predecessors.begin(); } 134 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 135 pred_iterator pred_end() { return Predecessors.end(); } 136 const_pred_iterator pred_end() const { return Predecessors.end(); } 137 pred_reverse_iterator pred_rbegin() 138 { return Predecessors.rbegin();} 139 const_pred_reverse_iterator pred_rbegin() const 140 { return Predecessors.rbegin();} 141 pred_reverse_iterator pred_rend() 142 { return Predecessors.rend(); } 143 const_pred_reverse_iterator pred_rend() const 144 { return Predecessors.rend(); } 145 unsigned pred_size() const { 146 return (unsigned)Predecessors.size(); 147 } 148 bool pred_empty() const { return Predecessors.empty(); } 149 succ_iterator succ_begin() { return Successors.begin(); } 150 const_succ_iterator succ_begin() const { return Successors.begin(); } 151 succ_iterator succ_end() { return Successors.end(); } 152 const_succ_iterator succ_end() const { return Successors.end(); } 153 succ_reverse_iterator succ_rbegin() 154 { return Successors.rbegin(); } 155 const_succ_reverse_iterator succ_rbegin() const 156 { return Successors.rbegin(); } 157 succ_reverse_iterator succ_rend() 158 { return Successors.rend(); } 159 const_succ_reverse_iterator succ_rend() const 160 { return Successors.rend(); } 161 unsigned succ_size() const { 162 return (unsigned)Successors.size(); 163 } 164 bool succ_empty() const { return Successors.empty(); } 165 166 // LiveIn management methods. 167 168 /// addLiveIn - Add the specified register as a live in. Note that it 169 /// is an error to add the same register to the same set more than once. 170 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 171 172 /// removeLiveIn - Remove the specified register from the live in set. 173 /// 174 void removeLiveIn(unsigned Reg); 175 176 /// isLiveIn - Return true if the specified register is in the live in set. 177 /// 178 bool isLiveIn(unsigned Reg) const; 179 180 // Iteration support for live in sets. These sets are kept in sorted 181 // order by their register number. 182 typedef std::vector<unsigned>::iterator livein_iterator; 183 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 184 livein_iterator livein_begin() { return LiveIns.begin(); } 185 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 186 livein_iterator livein_end() { return LiveIns.end(); } 187 const_livein_iterator livein_end() const { return LiveIns.end(); } 188 bool livein_empty() const { return LiveIns.empty(); } 189 190 /// getAlignment - Return alignment of the basic block. 191 /// 192 unsigned getAlignment() const { return Alignment; } 193 194 /// setAlignment - Set alignment of the basic block. 195 /// 196 void setAlignment(unsigned Align) { Alignment = Align; } 197 198 /// isLandingPad - Returns true if the block is a landing pad. That is 199 /// this basic block is entered via an exception handler. 200 bool isLandingPad() const { return IsLandingPad; } 201 202 /// setIsLandingPad - Indicates the block is a landing pad. That is 203 /// this basic block is entered via an exception handler. 204 void setIsLandingPad() { IsLandingPad = true; } 205 206 // Code Layout methods. 207 208 /// moveBefore/moveAfter - move 'this' block before or after the specified 209 /// block. This only moves the block, it does not modify the CFG or adjust 210 /// potential fall-throughs at the end of the block. 211 void moveBefore(MachineBasicBlock *NewAfter); 212 void moveAfter(MachineBasicBlock *NewBefore); 213 214 // Machine-CFG mutators 215 216 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 217 /// The Predecessors list of succ is automatically updated. 218 /// 219 void addSuccessor(MachineBasicBlock *succ); 220 221 /// removeSuccessor - Remove successor from the successors list of this 222 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 223 /// 224 void removeSuccessor(MachineBasicBlock *succ); 225 226 /// removeSuccessor - Remove specified successor from the successors list of 227 /// this MachineBasicBlock. The Predecessors list of succ is automatically 228 /// updated. Return the iterator to the element after the one removed. 229 /// 230 succ_iterator removeSuccessor(succ_iterator I); 231 232 /// transferSuccessors - Transfers all the successors from MBB to this 233 /// machine basic block (i.e., copies all the successors fromMBB and 234 /// remove all the successors fromBB). 235 void transferSuccessors(MachineBasicBlock *fromMBB); 236 237 /// isSuccessor - Return true if the specified MBB is a successor of this 238 /// block. 239 bool isSuccessor(MachineBasicBlock *MBB) const; 240 241 /// isLayoutSuccessor - Return true if the specified MBB will be emitted 242 /// immediately after this block, such that if this block exits by 243 /// falling through, control will transfer to the specified MBB. Note 244 /// that MBB need not be a successor at all, for example if this block 245 /// ends with an unconditional branch to some other block. 246 bool isLayoutSuccessor(MachineBasicBlock *MBB) const; 247 248 /// getFirstTerminator - returns an iterator to the first terminator 249 /// instruction of this basic block. If a terminator does not exist, 250 /// it returns end() 251 iterator getFirstTerminator(); 252 253 void pop_front() { Insts.pop_front(); } 254 void pop_back() { Insts.pop_back(); } 255 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 256 template<typename IT> 257 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 258 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 259 260 // erase - Remove the specified element or range from the instruction list. 261 // These functions delete any instructions removed. 262 // 263 iterator erase(iterator I) { return Insts.erase(I); } 264 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 265 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 266 void clear() { Insts.clear(); } 267 268 /// splice - Take an instruction from MBB 'Other' at the position From, 269 /// and insert it into this MBB right before 'where'. 270 void splice(iterator where, MachineBasicBlock *Other, iterator From) { 271 Insts.splice(where, Other->Insts, From); 272 } 273 274 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 275 /// To), and insert them into this MBB right before 'where'. 276 void splice(iterator where, MachineBasicBlock *Other, iterator From, 277 iterator To) { 278 Insts.splice(where, Other->Insts, From, To); 279 } 280 281 /// removeFromParent - This method unlinks 'this' from the containing 282 /// function, and returns it, but does not delete it. 283 MachineBasicBlock *removeFromParent(); 284 285 /// eraseFromParent - This method unlinks 'this' from the containing 286 /// function and deletes it. 287 void eraseFromParent(); 288 289 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 290 /// 'Old', change the code and CFG so that it branches to 'New' instead. 291 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 292 293 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 294 /// the CFG to be inserted. If we have proven that MBB can only branch to 295 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 296 /// DestB can be null. Besides DestA and DestB, retain other edges leading 297 /// to LandingPads (currently there can be only one; we don't check or require 298 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 299 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 300 MachineBasicBlock *DestB, 301 bool isCond); 302 303 // Debugging methods. 304 void dump() const; 305 void print(std::ostream &OS) const; 306 void print(std::ostream *OS) const { if (OS) print(*OS); } 307 308 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 309 /// level, unless they're not in a MachineFunction yet, in which case this 310 /// will return -1. 311 /// 312 int getNumber() const { return Number; } 313 void setNumber(int N) { Number = N; } 314 315private: // Methods used to maintain doubly linked list of blocks... 316 friend struct ilist_traits<MachineBasicBlock>; 317 318 // Machine-CFG mutators 319 320 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 321 /// Don't do this unless you know what you're doing, because it doesn't 322 /// update pred's successors list. Use pred->addSuccessor instead. 323 /// 324 void addPredecessor(MachineBasicBlock *pred); 325 326 /// removePredecessor - Remove pred as a predecessor of this 327 /// MachineBasicBlock. Don't do this unless you know what you're 328 /// doing, because it doesn't update pred's successors list. Use 329 /// pred->removeSuccessor instead. 330 /// 331 void removePredecessor(MachineBasicBlock *pred); 332}; 333 334std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB); 335 336//===--------------------------------------------------------------------===// 337// GraphTraits specializations for machine basic block graphs (machine-CFGs) 338//===--------------------------------------------------------------------===// 339 340// Provide specializations of GraphTraits to be able to treat a 341// MachineFunction as a graph of MachineBasicBlocks... 342// 343 344template <> struct GraphTraits<MachineBasicBlock *> { 345 typedef MachineBasicBlock NodeType; 346 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 347 348 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 349 static inline ChildIteratorType child_begin(NodeType *N) { 350 return N->succ_begin(); 351 } 352 static inline ChildIteratorType child_end(NodeType *N) { 353 return N->succ_end(); 354 } 355}; 356 357template <> struct GraphTraits<const MachineBasicBlock *> { 358 typedef const MachineBasicBlock NodeType; 359 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 360 361 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 362 static inline ChildIteratorType child_begin(NodeType *N) { 363 return N->succ_begin(); 364 } 365 static inline ChildIteratorType child_end(NodeType *N) { 366 return N->succ_end(); 367 } 368}; 369 370// Provide specializations of GraphTraits to be able to treat a 371// MachineFunction as a graph of MachineBasicBlocks... and to walk it 372// in inverse order. Inverse order for a function is considered 373// to be when traversing the predecessor edges of a MBB 374// instead of the successor edges. 375// 376template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 377 typedef MachineBasicBlock NodeType; 378 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 379 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 380 return G.Graph; 381 } 382 static inline ChildIteratorType child_begin(NodeType *N) { 383 return N->pred_begin(); 384 } 385 static inline ChildIteratorType child_end(NodeType *N) { 386 return N->pred_end(); 387 } 388}; 389 390template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 391 typedef const MachineBasicBlock NodeType; 392 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 393 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 394 return G.Graph; 395 } 396 static inline ChildIteratorType child_begin(NodeType *N) { 397 return N->pred_begin(); 398 } 399 static inline ChildIteratorType child_end(NodeType *N) { 400 return N->pred_end(); 401 } 402}; 403 404} // End llvm namespace 405 406#endif 407