MachineBasicBlock.h revision 1edb8e0910db4cda46a81a4abad80a2a755442aa
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_half_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 /// AddressTaken - Indicate that this basic block is potentially the 80 /// target of an indirect branch. 81 bool AddressTaken; 82 83 // Intrusive list support 84 MachineBasicBlock() {} 85 86 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb); 87 88 ~MachineBasicBlock(); 89 90 // MachineBasicBlocks are allocated and owned by MachineFunction. 91 friend class MachineFunction; 92 93public: 94 /// getBasicBlock - Return the LLVM basic block that this instance 95 /// corresponded to originally. 96 /// 97 const BasicBlock *getBasicBlock() const { return BB; } 98 99 /// hasAddressTaken - Test whether this block is potentially the target 100 /// of an indirect branch. 101 bool hasAddressTaken() const { return AddressTaken; } 102 103 /// setHasAddressTaken - Set this block to reflect that it potentially 104 /// is the target of an indirect branch. 105 void setHasAddressTaken() { AddressTaken = true; } 106 107 /// getParent - Return the MachineFunction containing this basic block. 108 /// 109 const MachineFunction *getParent() const { return xParent; } 110 MachineFunction *getParent() { return xParent; } 111 112 typedef Instructions::iterator iterator; 113 typedef Instructions::const_iterator const_iterator; 114 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 115 typedef std::reverse_iterator<iterator> reverse_iterator; 116 117 unsigned size() const { return (unsigned)Insts.size(); } 118 bool empty() const { return Insts.empty(); } 119 120 MachineInstr& front() { return Insts.front(); } 121 MachineInstr& back() { return Insts.back(); } 122 const MachineInstr& front() const { return Insts.front(); } 123 const MachineInstr& back() const { return Insts.back(); } 124 125 iterator begin() { return Insts.begin(); } 126 const_iterator begin() const { return Insts.begin(); } 127 iterator end() { return Insts.end(); } 128 const_iterator end() const { return Insts.end(); } 129 reverse_iterator rbegin() { return Insts.rbegin(); } 130 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 131 reverse_iterator rend () { return Insts.rend(); } 132 const_reverse_iterator rend () const { return Insts.rend(); } 133 134 // Machine-CFG iterators 135 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 136 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 137 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 138 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 139 typedef std::vector<MachineBasicBlock *>::reverse_iterator 140 pred_reverse_iterator; 141 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 142 const_pred_reverse_iterator; 143 typedef std::vector<MachineBasicBlock *>::reverse_iterator 144 succ_reverse_iterator; 145 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 146 const_succ_reverse_iterator; 147 148 pred_iterator pred_begin() { return Predecessors.begin(); } 149 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 150 pred_iterator pred_end() { return Predecessors.end(); } 151 const_pred_iterator pred_end() const { return Predecessors.end(); } 152 pred_reverse_iterator pred_rbegin() 153 { return Predecessors.rbegin();} 154 const_pred_reverse_iterator pred_rbegin() const 155 { return Predecessors.rbegin();} 156 pred_reverse_iterator pred_rend() 157 { return Predecessors.rend(); } 158 const_pred_reverse_iterator pred_rend() const 159 { return Predecessors.rend(); } 160 unsigned pred_size() const { 161 return (unsigned)Predecessors.size(); 162 } 163 bool pred_empty() const { return Predecessors.empty(); } 164 succ_iterator succ_begin() { return Successors.begin(); } 165 const_succ_iterator succ_begin() const { return Successors.begin(); } 166 succ_iterator succ_end() { return Successors.end(); } 167 const_succ_iterator succ_end() const { return Successors.end(); } 168 succ_reverse_iterator succ_rbegin() 169 { return Successors.rbegin(); } 170 const_succ_reverse_iterator succ_rbegin() const 171 { return Successors.rbegin(); } 172 succ_reverse_iterator succ_rend() 173 { return Successors.rend(); } 174 const_succ_reverse_iterator succ_rend() const 175 { return Successors.rend(); } 176 unsigned succ_size() const { 177 return (unsigned)Successors.size(); 178 } 179 bool succ_empty() const { return Successors.empty(); } 180 181 // LiveIn management methods. 182 183 /// addLiveIn - Add the specified register as a live in. Note that it 184 /// is an error to add the same register to the same set more than once. 185 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 186 187 /// removeLiveIn - Remove the specified register from the live in set. 188 /// 189 void removeLiveIn(unsigned Reg); 190 191 /// isLiveIn - Return true if the specified register is in the live in set. 192 /// 193 bool isLiveIn(unsigned Reg) const; 194 195 // Iteration support for live in sets. These sets are kept in sorted 196 // order by their register number. 197 typedef std::vector<unsigned>::iterator livein_iterator; 198 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 199 livein_iterator livein_begin() { return LiveIns.begin(); } 200 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 201 livein_iterator livein_end() { return LiveIns.end(); } 202 const_livein_iterator livein_end() const { return LiveIns.end(); } 203 bool livein_empty() const { return LiveIns.empty(); } 204 205 /// getAlignment - Return alignment of the basic block. 206 /// 207 unsigned getAlignment() const { return Alignment; } 208 209 /// setAlignment - Set alignment of the basic block. 210 /// 211 void setAlignment(unsigned Align) { Alignment = Align; } 212 213 /// isLandingPad - Returns true if the block is a landing pad. That is 214 /// this basic block is entered via an exception handler. 215 bool isLandingPad() const { return IsLandingPad; } 216 217 /// setIsLandingPad - Indicates the block is a landing pad. That is 218 /// this basic block is entered via an exception handler. 219 void setIsLandingPad() { IsLandingPad = true; } 220 221 // Code Layout methods. 222 223 /// moveBefore/moveAfter - move 'this' block before or after the specified 224 /// block. This only moves the block, it does not modify the CFG or adjust 225 /// potential fall-throughs at the end of the block. 226 void moveBefore(MachineBasicBlock *NewAfter); 227 void moveAfter(MachineBasicBlock *NewBefore); 228 229 // Machine-CFG mutators 230 231 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 232 /// The Predecessors list of succ is automatically updated. 233 /// 234 void addSuccessor(MachineBasicBlock *succ); 235 236 /// removeSuccessor - Remove successor from the successors list of this 237 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 238 /// 239 void removeSuccessor(MachineBasicBlock *succ); 240 241 /// removeSuccessor - Remove specified successor from the successors list of 242 /// this MachineBasicBlock. The Predecessors list of succ is automatically 243 /// updated. Return the iterator to the element after the one removed. 244 /// 245 succ_iterator removeSuccessor(succ_iterator I); 246 247 /// transferSuccessors - Transfers all the successors from MBB to this 248 /// machine basic block (i.e., copies all the successors fromMBB and 249 /// remove all the successors from fromMBB). 250 void transferSuccessors(MachineBasicBlock *fromMBB); 251 252 /// isSuccessor - Return true if the specified MBB is a successor of this 253 /// block. 254 bool isSuccessor(const MachineBasicBlock *MBB) const; 255 256 /// isLayoutSuccessor - Return true if the specified MBB will be emitted 257 /// immediately after this block, such that if this block exits by 258 /// falling through, control will transfer to the specified MBB. Note 259 /// that MBB need not be a successor at all, for example if this block 260 /// ends with an unconditional branch to some other block. 261 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; 262 263 /// getFirstTerminator - returns an iterator to the first terminator 264 /// instruction of this basic block. If a terminator does not exist, 265 /// it returns end() 266 iterator getFirstTerminator(); 267 268 /// isOnlyReachableViaFallthough - Return true if this basic block has 269 /// exactly one predecessor and the control transfer mechanism between 270 /// the predecessor and this block is a fall-through. 271 bool isOnlyReachableByFallthrough() const; 272 273 void pop_front() { Insts.pop_front(); } 274 void pop_back() { Insts.pop_back(); } 275 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 276 template<typename IT> 277 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 278 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 279 280 // erase - Remove the specified element or range from the instruction list. 281 // These functions delete any instructions removed. 282 // 283 iterator erase(iterator I) { return Insts.erase(I); } 284 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 285 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 286 void clear() { Insts.clear(); } 287 288 /// splice - Take an instruction from MBB 'Other' at the position From, 289 /// and insert it into this MBB right before 'where'. 290 void splice(iterator where, MachineBasicBlock *Other, iterator From) { 291 Insts.splice(where, Other->Insts, From); 292 } 293 294 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 295 /// To), and insert them into this MBB right before 'where'. 296 void splice(iterator where, MachineBasicBlock *Other, iterator From, 297 iterator To) { 298 Insts.splice(where, Other->Insts, From, To); 299 } 300 301 /// removeFromParent - This method unlinks 'this' from the containing 302 /// function, and returns it, but does not delete it. 303 MachineBasicBlock *removeFromParent(); 304 305 /// eraseFromParent - This method unlinks 'this' from the containing 306 /// function and deletes it. 307 void eraseFromParent(); 308 309 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 310 /// 'Old', change the code and CFG so that it branches to 'New' instead. 311 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 312 313 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 314 /// the CFG to be inserted. If we have proven that MBB can only branch to 315 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 316 /// DestB can be null. Besides DestA and DestB, retain other edges leading 317 /// to LandingPads (currently there can be only one; we don't check or require 318 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 319 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 320 MachineBasicBlock *DestB, 321 bool isCond); 322 323 // Debugging methods. 324 void dump() const; 325 void print(raw_ostream &OS) const; 326 327 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 328 /// level, unless they're not in a MachineFunction yet, in which case this 329 /// will return -1. 330 /// 331 int getNumber() const { return Number; } 332 void setNumber(int N) { Number = N; } 333 334private: // Methods used to maintain doubly linked list of blocks... 335 friend struct ilist_traits<MachineBasicBlock>; 336 337 // Machine-CFG mutators 338 339 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 340 /// Don't do this unless you know what you're doing, because it doesn't 341 /// update pred's successors list. Use pred->addSuccessor instead. 342 /// 343 void addPredecessor(MachineBasicBlock *pred); 344 345 /// removePredecessor - Remove pred as a predecessor of this 346 /// MachineBasicBlock. Don't do this unless you know what you're 347 /// doing, because it doesn't update pred's successors list. Use 348 /// pred->removeSuccessor instead. 349 /// 350 void removePredecessor(MachineBasicBlock *pred); 351}; 352 353raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 354 355//===--------------------------------------------------------------------===// 356// GraphTraits specializations for machine basic block graphs (machine-CFGs) 357//===--------------------------------------------------------------------===// 358 359// Provide specializations of GraphTraits to be able to treat a 360// MachineFunction as a graph of MachineBasicBlocks... 361// 362 363template <> struct GraphTraits<MachineBasicBlock *> { 364 typedef MachineBasicBlock NodeType; 365 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 366 367 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 368 static inline ChildIteratorType child_begin(NodeType *N) { 369 return N->succ_begin(); 370 } 371 static inline ChildIteratorType child_end(NodeType *N) { 372 return N->succ_end(); 373 } 374}; 375 376template <> struct GraphTraits<const MachineBasicBlock *> { 377 typedef const MachineBasicBlock NodeType; 378 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 379 380 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 381 static inline ChildIteratorType child_begin(NodeType *N) { 382 return N->succ_begin(); 383 } 384 static inline ChildIteratorType child_end(NodeType *N) { 385 return N->succ_end(); 386 } 387}; 388 389// Provide specializations of GraphTraits to be able to treat a 390// MachineFunction as a graph of MachineBasicBlocks... and to walk it 391// in inverse order. Inverse order for a function is considered 392// to be when traversing the predecessor edges of a MBB 393// instead of the successor edges. 394// 395template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 396 typedef MachineBasicBlock NodeType; 397 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 398 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 399 return G.Graph; 400 } 401 static inline ChildIteratorType child_begin(NodeType *N) { 402 return N->pred_begin(); 403 } 404 static inline ChildIteratorType child_end(NodeType *N) { 405 return N->pred_end(); 406 } 407}; 408 409template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 410 typedef const MachineBasicBlock NodeType; 411 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 412 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 413 return G.Graph; 414 } 415 static inline ChildIteratorType child_begin(NodeType *N) { 416 return N->pred_begin(); 417 } 418 static inline ChildIteratorType child_end(NodeType *N) { 419 return N->pred_end(); 420 } 421}; 422 423} // End llvm namespace 424 425#endif 426