MachineBasicBlock.h revision 372fefe8d24e40df2390fffeea0dc2dec611f88b
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 20namespace llvm { 21 22class BasicBlock; 23class MachineFunction; 24class raw_ostream; 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 MachineInstr *provideInitialHead() const { return createSentinel(); } 42 MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); } 43 static void noteHead(MachineInstr*, MachineInstr*) {} 44 45 void addNodeToList(MachineInstr* N); 46 void removeNodeFromList(MachineInstr* N); 47 void transferNodesFromList(ilist_traits &SrcTraits, 48 ilist_iterator<MachineInstr> first, 49 ilist_iterator<MachineInstr> last); 50 void deleteNode(MachineInstr *N); 51private: 52 void createNode(const MachineInstr &); 53}; 54 55class MachineBasicBlock : public ilist_node<MachineBasicBlock> { 56 typedef ilist<MachineInstr> Instructions; 57 Instructions Insts; 58 const BasicBlock *BB; 59 int Number; 60 MachineFunction *xParent; 61 62 /// Predecessors/Successors - Keep track of the predecessor / successor 63 /// basicblocks. 64 std::vector<MachineBasicBlock *> Predecessors; 65 std::vector<MachineBasicBlock *> Successors; 66 67 /// LiveIns - Keep track of the physical registers that are livein of 68 /// the basicblock. 69 std::vector<unsigned> LiveIns; 70 71 /// Alignment - Alignment of the basic block. Zero if the basic block does 72 /// not need to be aligned. 73 unsigned Alignment; 74 75 /// IsLandingPad - Indicate that this basic block is entered via an 76 /// exception handler. 77 bool IsLandingPad; 78 79 // Intrusive list support 80 MachineBasicBlock() {} 81 82 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb); 83 84 ~MachineBasicBlock(); 85 86 // MachineBasicBlocks are allocated and owned by MachineFunction. 87 friend class MachineFunction; 88 89public: 90 /// getBasicBlock - Return the LLVM basic block that this instance 91 /// corresponded to originally. 92 /// 93 const BasicBlock *getBasicBlock() const { return BB; } 94 95 /// getParent - Return the MachineFunction containing this basic block. 96 /// 97 const MachineFunction *getParent() const { return xParent; } 98 MachineFunction *getParent() { return xParent; } 99 100 typedef Instructions::iterator iterator; 101 typedef Instructions::const_iterator const_iterator; 102 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 103 typedef std::reverse_iterator<iterator> reverse_iterator; 104 105 unsigned size() const { return (unsigned)Insts.size(); } 106 bool empty() const { return Insts.empty(); } 107 108 MachineInstr& front() { return Insts.front(); } 109 MachineInstr& back() { return Insts.back(); } 110 const MachineInstr& front() const { return Insts.front(); } 111 const MachineInstr& back() const { return Insts.back(); } 112 113 iterator begin() { return Insts.begin(); } 114 const_iterator begin() const { return Insts.begin(); } 115 iterator end() { return Insts.end(); } 116 const_iterator end() const { return Insts.end(); } 117 reverse_iterator rbegin() { return Insts.rbegin(); } 118 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 119 reverse_iterator rend () { return Insts.rend(); } 120 const_reverse_iterator rend () const { return Insts.rend(); } 121 122 // Machine-CFG iterators 123 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 124 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 125 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 126 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 127 typedef std::vector<MachineBasicBlock *>::reverse_iterator 128 pred_reverse_iterator; 129 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 130 const_pred_reverse_iterator; 131 typedef std::vector<MachineBasicBlock *>::reverse_iterator 132 succ_reverse_iterator; 133 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 134 const_succ_reverse_iterator; 135 136 pred_iterator pred_begin() { return Predecessors.begin(); } 137 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 138 pred_iterator pred_end() { return Predecessors.end(); } 139 const_pred_iterator pred_end() const { return Predecessors.end(); } 140 pred_reverse_iterator pred_rbegin() 141 { return Predecessors.rbegin();} 142 const_pred_reverse_iterator pred_rbegin() const 143 { return Predecessors.rbegin();} 144 pred_reverse_iterator pred_rend() 145 { return Predecessors.rend(); } 146 const_pred_reverse_iterator pred_rend() const 147 { return Predecessors.rend(); } 148 unsigned pred_size() const { 149 return (unsigned)Predecessors.size(); 150 } 151 bool pred_empty() const { return Predecessors.empty(); } 152 succ_iterator succ_begin() { return Successors.begin(); } 153 const_succ_iterator succ_begin() const { return Successors.begin(); } 154 succ_iterator succ_end() { return Successors.end(); } 155 const_succ_iterator succ_end() const { return Successors.end(); } 156 succ_reverse_iterator succ_rbegin() 157 { return Successors.rbegin(); } 158 const_succ_reverse_iterator succ_rbegin() const 159 { return Successors.rbegin(); } 160 succ_reverse_iterator succ_rend() 161 { return Successors.rend(); } 162 const_succ_reverse_iterator succ_rend() const 163 { return Successors.rend(); } 164 unsigned succ_size() const { 165 return (unsigned)Successors.size(); 166 } 167 bool succ_empty() const { return Successors.empty(); } 168 169 // LiveIn management methods. 170 171 /// addLiveIn - Add the specified register as a live in. Note that it 172 /// is an error to add the same register to the same set more than once. 173 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 174 175 /// removeLiveIn - Remove the specified register from the live in set. 176 /// 177 void removeLiveIn(unsigned Reg); 178 179 /// isLiveIn - Return true if the specified register is in the live in set. 180 /// 181 bool isLiveIn(unsigned Reg) const; 182 183 // Iteration support for live in sets. These sets are kept in sorted 184 // order by their register number. 185 typedef std::vector<unsigned>::iterator livein_iterator; 186 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 187 livein_iterator livein_begin() { return LiveIns.begin(); } 188 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 189 livein_iterator livein_end() { return LiveIns.end(); } 190 const_livein_iterator livein_end() const { return LiveIns.end(); } 191 bool livein_empty() const { return LiveIns.empty(); } 192 193 /// getAlignment - Return alignment of the basic block. 194 /// 195 unsigned getAlignment() const { return Alignment; } 196 197 /// setAlignment - Set alignment of the basic block. 198 /// 199 void setAlignment(unsigned Align) { Alignment = Align; } 200 201 /// isLandingPad - Returns true if the block is a landing pad. That is 202 /// this basic block is entered via an exception handler. 203 bool isLandingPad() const { return IsLandingPad; } 204 205 /// setIsLandingPad - Indicates the block is a landing pad. That is 206 /// this basic block is entered via an exception handler. 207 void setIsLandingPad() { IsLandingPad = true; } 208 209 // Code Layout methods. 210 211 /// moveBefore/moveAfter - move 'this' block before or after the specified 212 /// block. This only moves the block, it does not modify the CFG or adjust 213 /// potential fall-throughs at the end of the block. 214 void moveBefore(MachineBasicBlock *NewAfter); 215 void moveAfter(MachineBasicBlock *NewBefore); 216 217 // Machine-CFG mutators 218 219 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 220 /// The Predecessors list of succ is automatically updated. 221 /// 222 void addSuccessor(MachineBasicBlock *succ); 223 224 /// removeSuccessor - Remove successor from the successors list of this 225 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 226 /// 227 void removeSuccessor(MachineBasicBlock *succ); 228 229 /// removeSuccessor - Remove specified successor from the successors list of 230 /// this MachineBasicBlock. The Predecessors list of succ is automatically 231 /// updated. Return the iterator to the element after the one removed. 232 /// 233 succ_iterator removeSuccessor(succ_iterator I); 234 235 /// transferSuccessors - Transfers all the successors from MBB to this 236 /// machine basic block (i.e., copies all the successors fromMBB and 237 /// remove all the successors fromBB). 238 void transferSuccessors(MachineBasicBlock *fromMBB); 239 240 /// isSuccessor - Return true if the specified MBB is a successor of this 241 /// block. 242 bool isSuccessor(const MachineBasicBlock *MBB) const; 243 244 /// isLayoutSuccessor - Return true if the specified MBB will be emitted 245 /// immediately after this block, such that if this block exits by 246 /// falling through, control will transfer to the specified MBB. Note 247 /// that MBB need not be a successor at all, for example if this block 248 /// ends with an unconditional branch to some other block. 249 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; 250 251 /// getFirstTerminator - returns an iterator to the first terminator 252 /// instruction of this basic block. If a terminator does not exist, 253 /// it returns end() 254 iterator getFirstTerminator(); 255 256 /// isOnlyReachableViaFallthough - Return true if this basic block has 257 /// exactly one predecessor and the control transfer mechanism between 258 /// the predecessor and this block is a fall-through. 259 bool isOnlyReachableByFallthrough() const; 260 261 void pop_front() { Insts.pop_front(); } 262 void pop_back() { Insts.pop_back(); } 263 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 264 template<typename IT> 265 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 266 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 267 268 // erase - Remove the specified element or range from the instruction list. 269 // These functions delete any instructions removed. 270 // 271 iterator erase(iterator I) { return Insts.erase(I); } 272 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 273 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 274 void clear() { Insts.clear(); } 275 276 /// splice - Take an instruction from MBB 'Other' at the position From, 277 /// and insert it into this MBB right before 'where'. 278 void splice(iterator where, MachineBasicBlock *Other, iterator From) { 279 Insts.splice(where, Other->Insts, From); 280 } 281 282 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 283 /// To), and insert them into this MBB right before 'where'. 284 void splice(iterator where, MachineBasicBlock *Other, iterator From, 285 iterator To) { 286 Insts.splice(where, Other->Insts, From, To); 287 } 288 289 /// removeFromParent - This method unlinks 'this' from the containing 290 /// function, and returns it, but does not delete it. 291 MachineBasicBlock *removeFromParent(); 292 293 /// eraseFromParent - This method unlinks 'this' from the containing 294 /// function and deletes it. 295 void eraseFromParent(); 296 297 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 298 /// 'Old', change the code and CFG so that it branches to 'New' instead. 299 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 300 301 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 302 /// the CFG to be inserted. If we have proven that MBB can only branch to 303 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 304 /// DestB can be null. Besides DestA and DestB, retain other edges leading 305 /// to LandingPads (currently there can be only one; we don't check or require 306 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 307 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 308 MachineBasicBlock *DestB, 309 bool isCond); 310 311 // Debugging methods. 312 void dump() const; 313 void print(std::ostream &OS) const; 314 void print(raw_ostream &OS) const; 315 316 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 317 /// level, unless they're not in a MachineFunction yet, in which case this 318 /// will return -1. 319 /// 320 int getNumber() const { return Number; } 321 void setNumber(int N) { Number = N; } 322 323private: // Methods used to maintain doubly linked list of blocks... 324 friend struct ilist_traits<MachineBasicBlock>; 325 326 // Machine-CFG mutators 327 328 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 329 /// Don't do this unless you know what you're doing, because it doesn't 330 /// update pred's successors list. Use pred->addSuccessor instead. 331 /// 332 void addPredecessor(MachineBasicBlock *pred); 333 334 /// removePredecessor - Remove pred as a predecessor of this 335 /// MachineBasicBlock. Don't do this unless you know what you're 336 /// doing, because it doesn't update pred's successors list. Use 337 /// pred->removeSuccessor instead. 338 /// 339 void removePredecessor(MachineBasicBlock *pred); 340}; 341 342std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB); 343raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 344 345//===--------------------------------------------------------------------===// 346// GraphTraits specializations for machine basic block graphs (machine-CFGs) 347//===--------------------------------------------------------------------===// 348 349// Provide specializations of GraphTraits to be able to treat a 350// MachineFunction as a graph of MachineBasicBlocks... 351// 352 353template <> struct GraphTraits<MachineBasicBlock *> { 354 typedef MachineBasicBlock NodeType; 355 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 356 357 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 358 static inline ChildIteratorType child_begin(NodeType *N) { 359 return N->succ_begin(); 360 } 361 static inline ChildIteratorType child_end(NodeType *N) { 362 return N->succ_end(); 363 } 364}; 365 366template <> struct GraphTraits<const MachineBasicBlock *> { 367 typedef const MachineBasicBlock NodeType; 368 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 369 370 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 371 static inline ChildIteratorType child_begin(NodeType *N) { 372 return N->succ_begin(); 373 } 374 static inline ChildIteratorType child_end(NodeType *N) { 375 return N->succ_end(); 376 } 377}; 378 379// Provide specializations of GraphTraits to be able to treat a 380// MachineFunction as a graph of MachineBasicBlocks... and to walk it 381// in inverse order. Inverse order for a function is considered 382// to be when traversing the predecessor edges of a MBB 383// instead of the successor edges. 384// 385template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 386 typedef MachineBasicBlock NodeType; 387 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 388 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 389 return G.Graph; 390 } 391 static inline ChildIteratorType child_begin(NodeType *N) { 392 return N->pred_begin(); 393 } 394 static inline ChildIteratorType child_end(NodeType *N) { 395 return N->pred_end(); 396 } 397}; 398 399template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 400 typedef const MachineBasicBlock NodeType; 401 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 402 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 403 return G.Graph; 404 } 405 static inline ChildIteratorType child_begin(NodeType *N) { 406 return N->pred_begin(); 407 } 408 static inline ChildIteratorType child_end(NodeType *N) { 409 return N->pred_end(); 410 } 411}; 412 413} // End llvm namespace 414 415#endif 416