MachineBasicBlock.h revision 8e8b8a223c2b0e69f44c0639f846260c8011668f
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 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 { return &Sentinel; } 37 void destroySentinel(MachineInstr *) const {} 38 39 void addNodeToList(MachineInstr* N); 40 void removeNodeFromList(MachineInstr* N); 41 void transferNodesFromList(ilist_traits &SrcTraits, 42 ilist_iterator<MachineInstr> first, 43 ilist_iterator<MachineInstr> last); 44 void deleteNode(MachineInstr *N); 45private: 46 void createNode(const MachineInstr &); 47}; 48 49class MachineBasicBlock : public ilist_node<MachineBasicBlock> { 50 typedef ilist<MachineInstr> Instructions; 51 Instructions Insts; 52 const BasicBlock *BB; 53 int Number; 54 MachineFunction *xParent; 55 56 /// Predecessors/Successors - Keep track of the predecessor / successor 57 /// basicblocks. 58 std::vector<MachineBasicBlock *> Predecessors; 59 std::vector<MachineBasicBlock *> Successors; 60 61 /// LiveIns - Keep track of the physical registers that are livein of 62 /// the basicblock. 63 std::vector<unsigned> LiveIns; 64 65 /// Alignment - Alignment of the basic block. Zero if the basic block does 66 /// not need to be aligned. 67 unsigned Alignment; 68 69 /// IsLandingPad - Indicate that this basic block is entered via an 70 /// exception handler. 71 bool IsLandingPad; 72 73 // Intrusive list support 74 friend struct ilist_sentinel_traits<MachineBasicBlock>; 75 MachineBasicBlock() {} 76 77 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb); 78 79 ~MachineBasicBlock(); 80 81 // MachineBasicBlocks are allocated and owned by MachineFunction. 82 friend class MachineFunction; 83 84public: 85 /// getBasicBlock - Return the LLVM basic block that this instance 86 /// corresponded to originally. 87 /// 88 const BasicBlock *getBasicBlock() const { return BB; } 89 90 /// getParent - Return the MachineFunction containing this basic block. 91 /// 92 const MachineFunction *getParent() const { return xParent; } 93 MachineFunction *getParent() { return xParent; } 94 95 typedef Instructions::iterator iterator; 96 typedef Instructions::const_iterator const_iterator; 97 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 98 typedef std::reverse_iterator<iterator> reverse_iterator; 99 100 unsigned size() const { return (unsigned)Insts.size(); } 101 bool empty() const { return Insts.empty(); } 102 103 MachineInstr& front() { return Insts.front(); } 104 MachineInstr& back() { return Insts.back(); } 105 const MachineInstr& front() const { return Insts.front(); } 106 const MachineInstr& back() const { return Insts.back(); } 107 108 iterator begin() { return Insts.begin(); } 109 const_iterator begin() const { return Insts.begin(); } 110 iterator end() { return Insts.end(); } 111 const_iterator end() const { return Insts.end(); } 112 reverse_iterator rbegin() { return Insts.rbegin(); } 113 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 114 reverse_iterator rend () { return Insts.rend(); } 115 const_reverse_iterator rend () const { return Insts.rend(); } 116 117 // Machine-CFG iterators 118 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 119 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 120 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 121 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 122 typedef std::vector<MachineBasicBlock *>::reverse_iterator 123 pred_reverse_iterator; 124 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 125 const_pred_reverse_iterator; 126 typedef std::vector<MachineBasicBlock *>::reverse_iterator 127 succ_reverse_iterator; 128 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 129 const_succ_reverse_iterator; 130 131 pred_iterator pred_begin() { return Predecessors.begin(); } 132 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 133 pred_iterator pred_end() { return Predecessors.end(); } 134 const_pred_iterator pred_end() const { return Predecessors.end(); } 135 pred_reverse_iterator pred_rbegin() 136 { return Predecessors.rbegin();} 137 const_pred_reverse_iterator pred_rbegin() const 138 { return Predecessors.rbegin();} 139 pred_reverse_iterator pred_rend() 140 { return Predecessors.rend(); } 141 const_pred_reverse_iterator pred_rend() const 142 { return Predecessors.rend(); } 143 unsigned pred_size() const { 144 return (unsigned)Predecessors.size(); 145 } 146 bool pred_empty() const { return Predecessors.empty(); } 147 succ_iterator succ_begin() { return Successors.begin(); } 148 const_succ_iterator succ_begin() const { return Successors.begin(); } 149 succ_iterator succ_end() { return Successors.end(); } 150 const_succ_iterator succ_end() const { return Successors.end(); } 151 succ_reverse_iterator succ_rbegin() 152 { return Successors.rbegin(); } 153 const_succ_reverse_iterator succ_rbegin() const 154 { return Successors.rbegin(); } 155 succ_reverse_iterator succ_rend() 156 { return Successors.rend(); } 157 const_succ_reverse_iterator succ_rend() const 158 { return Successors.rend(); } 159 unsigned succ_size() const { 160 return (unsigned)Successors.size(); 161 } 162 bool succ_empty() const { return Successors.empty(); } 163 164 // LiveIn management methods. 165 166 /// addLiveIn - Add the specified register as a live in. Note that it 167 /// is an error to add the same register to the same set more than once. 168 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 169 170 /// removeLiveIn - Remove the specified register from the live in set. 171 /// 172 void removeLiveIn(unsigned Reg); 173 174 /// isLiveIn - Return true if the specified register is in the live in set. 175 /// 176 bool isLiveIn(unsigned Reg) const; 177 178 // Iteration support for live in sets. These sets are kept in sorted 179 // order by their register number. 180 typedef std::vector<unsigned>::iterator livein_iterator; 181 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 182 livein_iterator livein_begin() { return LiveIns.begin(); } 183 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 184 livein_iterator livein_end() { return LiveIns.end(); } 185 const_livein_iterator livein_end() const { return LiveIns.end(); } 186 bool livein_empty() const { return LiveIns.empty(); } 187 188 /// getAlignment - Return alignment of the basic block. 189 /// 190 unsigned getAlignment() const { return Alignment; } 191 192 /// setAlignment - Set alignment of the basic block. 193 /// 194 void setAlignment(unsigned Align) { Alignment = Align; } 195 196 /// isLandingPad - Returns true if the block is a landing pad. That is 197 /// this basic block is entered via an exception handler. 198 bool isLandingPad() const { return IsLandingPad; } 199 200 /// setIsLandingPad - Indicates the block is a landing pad. That is 201 /// this basic block is entered via an exception handler. 202 void setIsLandingPad() { IsLandingPad = true; } 203 204 // Code Layout methods. 205 206 /// moveBefore/moveAfter - move 'this' block before or after the specified 207 /// block. This only moves the block, it does not modify the CFG or adjust 208 /// potential fall-throughs at the end of the block. 209 void moveBefore(MachineBasicBlock *NewAfter); 210 void moveAfter(MachineBasicBlock *NewBefore); 211 212 // Machine-CFG mutators 213 214 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 215 /// The Predecessors list of succ is automatically updated. 216 /// 217 void addSuccessor(MachineBasicBlock *succ); 218 219 /// removeSuccessor - Remove successor from the successors list of this 220 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 221 /// 222 void removeSuccessor(MachineBasicBlock *succ); 223 224 /// removeSuccessor - Remove specified successor from the successors list of 225 /// this MachineBasicBlock. The Predecessors list of succ is automatically 226 /// updated. Return the iterator to the element after the one removed. 227 /// 228 succ_iterator removeSuccessor(succ_iterator I); 229 230 /// transferSuccessors - Transfers all the successors from MBB to this 231 /// machine basic block (i.e., copies all the successors fromMBB and 232 /// remove all the successors fromBB). 233 void transferSuccessors(MachineBasicBlock *fromMBB); 234 235 /// isSuccessor - Return true if the specified MBB is a successor of this 236 /// block. 237 bool isSuccessor(MachineBasicBlock *MBB) const; 238 239 /// isLayoutSuccessor - Return true if the specified MBB will be emitted 240 /// immediately after this block, such that if this block exits by 241 /// falling through, control will transfer to the specified MBB. Note 242 /// that MBB need not be a successor at all, for example if this block 243 /// ends with an unconditional branch to some other block. 244 bool isLayoutSuccessor(MachineBasicBlock *MBB) const; 245 246 /// getFirstTerminator - returns an iterator to the first terminator 247 /// instruction of this basic block. If a terminator does not exist, 248 /// it returns end() 249 iterator getFirstTerminator(); 250 251 void pop_front() { Insts.pop_front(); } 252 void pop_back() { Insts.pop_back(); } 253 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 254 template<typename IT> 255 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 256 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 257 258 // erase - Remove the specified element or range from the instruction list. 259 // These functions delete any instructions removed. 260 // 261 iterator erase(iterator I) { return Insts.erase(I); } 262 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 263 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 264 void clear() { Insts.clear(); } 265 266 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 267 /// To), and insert them into this MBB right before 'where'. 268 void splice(iterator where, MachineBasicBlock *Other, iterator From, 269 iterator To) { 270 Insts.splice(where, Other->Insts, From, To); 271 } 272 273 /// removeFromParent - This method unlinks 'this' from the containing 274 /// function, and returns it, but does not delete it. 275 MachineBasicBlock *removeFromParent(); 276 277 /// eraseFromParent - This method unlinks 'this' from the containing 278 /// function and deletes it. 279 void eraseFromParent(); 280 281 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 282 /// 'Old', change the code and CFG so that it branches to 'New' instead. 283 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 284 285 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 286 /// the CFG to be inserted. If we have proven that MBB can only branch to 287 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 288 /// DestB can be null. Besides DestA and DestB, retain other edges leading 289 /// to LandingPads (currently there can be only one; we don't check or require 290 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 291 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 292 MachineBasicBlock *DestB, 293 bool isCond); 294 295 // Debugging methods. 296 void dump() const; 297 void print(std::ostream &OS) const; 298 void print(std::ostream *OS) const { if (OS) print(*OS); } 299 300 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 301 /// level, unless they're not in a MachineFunction yet, in which case this 302 /// will return -1. 303 /// 304 int getNumber() const { return Number; } 305 void setNumber(int N) { Number = N; } 306 307private: // Methods used to maintain doubly linked list of blocks... 308 friend struct ilist_traits<MachineBasicBlock>; 309 310 // Machine-CFG mutators 311 312 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 313 /// Don't do this unless you know what you're doing, because it doesn't 314 /// update pred's successors list. Use pred->addSuccessor instead. 315 /// 316 void addPredecessor(MachineBasicBlock *pred); 317 318 /// removePredecessor - Remove pred as a predecessor of this 319 /// MachineBasicBlock. Don't do this unless you know what you're 320 /// doing, because it doesn't update pred's successors list. Use 321 /// pred->removeSuccessor instead. 322 /// 323 void removePredecessor(MachineBasicBlock *pred); 324}; 325 326std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB); 327 328//===--------------------------------------------------------------------===// 329// GraphTraits specializations for machine basic block graphs (machine-CFGs) 330//===--------------------------------------------------------------------===// 331 332// Provide specializations of GraphTraits to be able to treat a 333// MachineFunction as a graph of MachineBasicBlocks... 334// 335 336template <> struct GraphTraits<MachineBasicBlock *> { 337 typedef MachineBasicBlock NodeType; 338 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 339 340 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 341 static inline ChildIteratorType child_begin(NodeType *N) { 342 return N->succ_begin(); 343 } 344 static inline ChildIteratorType child_end(NodeType *N) { 345 return N->succ_end(); 346 } 347}; 348 349template <> struct GraphTraits<const MachineBasicBlock *> { 350 typedef const MachineBasicBlock NodeType; 351 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 352 353 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 354 static inline ChildIteratorType child_begin(NodeType *N) { 355 return N->succ_begin(); 356 } 357 static inline ChildIteratorType child_end(NodeType *N) { 358 return N->succ_end(); 359 } 360}; 361 362// Provide specializations of GraphTraits to be able to treat a 363// MachineFunction as a graph of MachineBasicBlocks... and to walk it 364// in inverse order. Inverse order for a function is considered 365// to be when traversing the predecessor edges of a MBB 366// instead of the successor edges. 367// 368template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 369 typedef MachineBasicBlock NodeType; 370 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 371 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 372 return G.Graph; 373 } 374 static inline ChildIteratorType child_begin(NodeType *N) { 375 return N->pred_begin(); 376 } 377 static inline ChildIteratorType child_end(NodeType *N) { 378 return N->pred_end(); 379 } 380}; 381 382template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 383 typedef const MachineBasicBlock NodeType; 384 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 385 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 386 return G.Graph; 387 } 388 static inline ChildIteratorType child_begin(NodeType *N) { 389 return N->pred_begin(); 390 } 391 static inline ChildIteratorType child_end(NodeType *N) { 392 return N->pred_end(); 393 } 394}; 395 396} // End llvm namespace 397 398#endif 399