MachineBasicBlock.h revision 8e4018e2de52c534405d7155c7009d0b35afb861
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(); } 105 106 iterator begin() { return Insts.begin(); } 107 const_iterator begin() const { return Insts.begin(); } 108 iterator end() { return Insts.end(); } 109 const_iterator end() const { return Insts.end(); } 110 reverse_iterator rbegin() { return Insts.rbegin(); } 111 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 112 reverse_iterator rend () { return Insts.rend(); } 113 const_reverse_iterator rend () const { return Insts.rend(); } 114 115 // Machine-CFG iterators 116 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 117 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 118 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 119 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 120 typedef std::vector<MachineBasicBlock *>::reverse_iterator 121 pred_reverse_iterator; 122 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 123 const_pred_reverse_iterator; 124 typedef std::vector<MachineBasicBlock *>::reverse_iterator 125 succ_reverse_iterator; 126 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 127 const_succ_reverse_iterator; 128 129 pred_iterator pred_begin() { return Predecessors.begin(); } 130 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 131 pred_iterator pred_end() { return Predecessors.end(); } 132 const_pred_iterator pred_end() const { return Predecessors.end(); } 133 pred_reverse_iterator pred_rbegin() 134 { return Predecessors.rbegin();} 135 const_pred_reverse_iterator pred_rbegin() const 136 { return Predecessors.rbegin();} 137 pred_reverse_iterator pred_rend() 138 { return Predecessors.rend(); } 139 const_pred_reverse_iterator pred_rend() const 140 { return Predecessors.rend(); } 141 unsigned pred_size() const { 142 return (unsigned)Predecessors.size(); 143 } 144 bool pred_empty() const { return Predecessors.empty(); } 145 succ_iterator succ_begin() { return Successors.begin(); } 146 const_succ_iterator succ_begin() const { return Successors.begin(); } 147 succ_iterator succ_end() { return Successors.end(); } 148 const_succ_iterator succ_end() const { return Successors.end(); } 149 succ_reverse_iterator succ_rbegin() 150 { return Successors.rbegin(); } 151 const_succ_reverse_iterator succ_rbegin() const 152 { return Successors.rbegin(); } 153 succ_reverse_iterator succ_rend() 154 { return Successors.rend(); } 155 const_succ_reverse_iterator succ_rend() const 156 { return Successors.rend(); } 157 unsigned succ_size() const { 158 return (unsigned)Successors.size(); 159 } 160 bool succ_empty() const { return Successors.empty(); } 161 162 // LiveIn management methods. 163 164 /// addLiveIn - Add the specified register as a live in. Note that it 165 /// is an error to add the same register to the same set more than once. 166 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 167 168 /// removeLiveIn - Remove the specified register from the live in set. 169 /// 170 void removeLiveIn(unsigned Reg); 171 172 /// isLiveIn - Return true if the specified register is in the live in set. 173 /// 174 bool isLiveIn(unsigned Reg) const; 175 176 // Iteration support for live in sets. These sets are kept in sorted 177 // order by their register number. 178 typedef std::vector<unsigned>::iterator livein_iterator; 179 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 180 livein_iterator livein_begin() { return LiveIns.begin(); } 181 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 182 livein_iterator livein_end() { return LiveIns.end(); } 183 const_livein_iterator livein_end() const { return LiveIns.end(); } 184 bool livein_empty() const { return LiveIns.empty(); } 185 186 /// getAlignment - Return alignment of the basic block. 187 /// 188 unsigned getAlignment() const { return Alignment; } 189 190 /// setAlignment - Set alignment of the basic block. 191 /// 192 void setAlignment(unsigned Align) { Alignment = Align; } 193 194 /// isLandingPad - Returns true if the block is a landing pad. That is 195 /// this basic block is entered via an exception handler. 196 bool isLandingPad() const { return IsLandingPad; } 197 198 /// setIsLandingPad - Indicates the block is a landing pad. That is 199 /// this basic block is entered via an exception handler. 200 void setIsLandingPad() { IsLandingPad = true; } 201 202 // Code Layout methods. 203 204 /// moveBefore/moveAfter - move 'this' block before or after the specified 205 /// block. This only moves the block, it does not modify the CFG or adjust 206 /// potential fall-throughs at the end of the block. 207 void moveBefore(MachineBasicBlock *NewAfter); 208 void moveAfter(MachineBasicBlock *NewBefore); 209 210 // Machine-CFG mutators 211 212 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 213 /// The Predecessors list of succ is automatically updated. 214 /// 215 void addSuccessor(MachineBasicBlock *succ); 216 217 /// removeSuccessor - Remove successor from the successors list of this 218 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 219 /// 220 void removeSuccessor(MachineBasicBlock *succ); 221 222 /// removeSuccessor - Remove specified successor from the successors list of 223 /// this MachineBasicBlock. The Predecessors list of succ is automatically 224 /// updated. Return the iterator to the element after the one removed. 225 /// 226 succ_iterator removeSuccessor(succ_iterator I); 227 228 /// transferSuccessors - Transfers all the successors from MBB to this 229 /// machine basic block (i.e., copies all the successors fromMBB and 230 /// remove all the successors fromBB). 231 void transferSuccessors(MachineBasicBlock *fromMBB); 232 233 /// isSuccessor - Return true if the specified MBB is a successor of this 234 /// block. 235 bool isSuccessor(MachineBasicBlock *MBB) const; 236 237 /// getFirstTerminator - returns an iterator to the first terminator 238 /// instruction of this basic block. If a terminator does not exist, 239 /// it returns end() 240 iterator getFirstTerminator(); 241 242 void pop_front() { Insts.pop_front(); } 243 void pop_back() { Insts.pop_back(); } 244 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 245 template<typename IT> 246 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 247 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 248 249 // erase - Remove the specified element or range from the instruction list. 250 // These functions delete any instructions removed. 251 // 252 iterator erase(iterator I) { return Insts.erase(I); } 253 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 254 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 255 void clear() { Insts.clear(); } 256 257 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 258 /// To), and insert them into this MBB right before 'where'. 259 void splice(iterator where, MachineBasicBlock *Other, iterator From, 260 iterator To) { 261 Insts.splice(where, Other->Insts, From, To); 262 } 263 264 /// removeFromParent - This method unlinks 'this' from the containing 265 /// function, and returns it, but does not delete it. 266 MachineBasicBlock *removeFromParent(); 267 268 /// eraseFromParent - This method unlinks 'this' from the containing 269 /// function and deletes it. 270 void eraseFromParent(); 271 272 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 273 /// 'Old', change the code and CFG so that it branches to 'New' instead. 274 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 275 276 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 277 /// the CFG to be inserted. If we have proven that MBB can only branch to 278 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 279 /// DestB can be null. Besides DestA and DestB, retain other edges leading 280 /// to LandingPads (currently there can be only one; we don't check or require 281 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 282 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 283 MachineBasicBlock *DestB, 284 bool isCond); 285 286 // Debugging methods. 287 void dump() const; 288 void print(std::ostream &OS) const; 289 void print(std::ostream *OS) const { if (OS) print(*OS); } 290 291 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 292 /// level, unless they're not in a MachineFunction yet, in which case this 293 /// will return -1. 294 /// 295 int getNumber() const { return Number; } 296 void setNumber(int N) { Number = N; } 297 298private: // Methods used to maintain doubly linked list of blocks... 299 friend struct ilist_traits<MachineBasicBlock>; 300 301 // Machine-CFG mutators 302 303 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 304 /// Don't do this unless you know what you're doing, because it doesn't 305 /// update pred's successors list. Use pred->addSuccessor instead. 306 /// 307 void addPredecessor(MachineBasicBlock *pred); 308 309 /// removePredecessor - Remove pred as a predecessor of this 310 /// MachineBasicBlock. Don't do this unless you know what you're 311 /// doing, because it doesn't update pred's successors list. Use 312 /// pred->removeSuccessor instead. 313 /// 314 void removePredecessor(MachineBasicBlock *pred); 315}; 316 317std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB); 318 319//===--------------------------------------------------------------------===// 320// GraphTraits specializations for machine basic block graphs (machine-CFGs) 321//===--------------------------------------------------------------------===// 322 323// Provide specializations of GraphTraits to be able to treat a 324// MachineFunction as a graph of MachineBasicBlocks... 325// 326 327template <> struct GraphTraits<MachineBasicBlock *> { 328 typedef MachineBasicBlock NodeType; 329 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 330 331 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 332 static inline ChildIteratorType child_begin(NodeType *N) { 333 return N->succ_begin(); 334 } 335 static inline ChildIteratorType child_end(NodeType *N) { 336 return N->succ_end(); 337 } 338}; 339 340template <> struct GraphTraits<const MachineBasicBlock *> { 341 typedef const MachineBasicBlock NodeType; 342 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 343 344 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 345 static inline ChildIteratorType child_begin(NodeType *N) { 346 return N->succ_begin(); 347 } 348 static inline ChildIteratorType child_end(NodeType *N) { 349 return N->succ_end(); 350 } 351}; 352 353// Provide specializations of GraphTraits to be able to treat a 354// MachineFunction as a graph of MachineBasicBlocks... and to walk it 355// in inverse order. Inverse order for a function is considered 356// to be when traversing the predecessor edges of a MBB 357// instead of the successor edges. 358// 359template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 360 typedef MachineBasicBlock NodeType; 361 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 362 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 363 return G.Graph; 364 } 365 static inline ChildIteratorType child_begin(NodeType *N) { 366 return N->pred_begin(); 367 } 368 static inline ChildIteratorType child_end(NodeType *N) { 369 return N->pred_end(); 370 } 371}; 372 373template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 374 typedef const MachineBasicBlock NodeType; 375 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 376 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 377 return G.Graph; 378 } 379 static inline ChildIteratorType child_begin(NodeType *N) { 380 return N->pred_begin(); 381 } 382 static inline ChildIteratorType child_end(NodeType *N) { 383 return N->pred_end(); 384 } 385}; 386 387} // End llvm namespace 388 389#endif 390