MachineBasicBlock.h revision fed90b6d097d50881afb45e4d79f430db66dd741
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 <> 27class ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> { 28 mutable MachineInstr Sentinel; 29 30 // this is only set by the MachineBasicBlock owning the LiveList 31 friend class MachineBasicBlock; 32 MachineBasicBlock* Parent; 33 34public: 35 MachineInstr *createSentinel() const { return &Sentinel; } 36 void destroySentinel(MachineInstr *) const {} 37 38 void addNodeToList(MachineInstr* N); 39 void removeNodeFromList(MachineInstr* N); 40 void transferNodesFromList(ilist_traits &SrcTraits, 41 ilist_iterator<MachineInstr> first, 42 ilist_iterator<MachineInstr> last); 43 void deleteNode(MachineInstr *N); 44private: 45 void createNode(const MachineInstr &); 46}; 47 48class MachineBasicBlock : public ilist_node<MachineBasicBlock> { 49 typedef ilist<MachineInstr> Instructions; 50 Instructions Insts; 51 const BasicBlock *BB; 52 int Number; 53 MachineFunction *xParent; 54 55 /// Predecessors/Successors - Keep track of the predecessor / successor 56 /// basicblocks. 57 std::vector<MachineBasicBlock *> Predecessors; 58 std::vector<MachineBasicBlock *> Successors; 59 60 /// LiveIns - Keep track of the physical registers that are livein of 61 /// the basicblock. 62 std::vector<unsigned> LiveIns; 63 64 /// Alignment - Alignment of the basic block. Zero if the basic block does 65 /// not need to be aligned. 66 unsigned Alignment; 67 68 /// IsLandingPad - Indicate that this basic block is entered via an 69 /// exception handler. 70 bool IsLandingPad; 71 72 // Intrusive list support 73 friend class ilist_sentinel_traits<MachineBasicBlock>; 74 MachineBasicBlock() {} 75 76 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb); 77 78 ~MachineBasicBlock(); 79 80 // MachineBasicBlocks are allocated and owned by MachineFunction. 81 friend class MachineFunction; 82 83public: 84 /// getBasicBlock - Return the LLVM basic block that this instance 85 /// corresponded to originally. 86 /// 87 const BasicBlock *getBasicBlock() const { return BB; } 88 89 /// getParent - Return the MachineFunction containing this basic block. 90 /// 91 const MachineFunction *getParent() const { return xParent; } 92 MachineFunction *getParent() { return xParent; } 93 94 typedef Instructions::iterator iterator; 95 typedef Instructions::const_iterator const_iterator; 96 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 97 typedef std::reverse_iterator<iterator> reverse_iterator; 98 99 unsigned size() const { return (unsigned)Insts.size(); } 100 bool empty() const { return Insts.empty(); } 101 102 MachineInstr& front() { return Insts.front(); } 103 MachineInstr& back() { return Insts.back(); } 104 105 iterator begin() { return Insts.begin(); } 106 const_iterator begin() const { return Insts.begin(); } 107 iterator end() { return Insts.end(); } 108 const_iterator end() const { return Insts.end(); } 109 reverse_iterator rbegin() { return Insts.rbegin(); } 110 const_reverse_iterator rbegin() const { return Insts.rbegin(); } 111 reverse_iterator rend () { return Insts.rend(); } 112 const_reverse_iterator rend () const { return Insts.rend(); } 113 114 // Machine-CFG iterators 115 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator; 116 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator; 117 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator; 118 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator; 119 typedef std::vector<MachineBasicBlock *>::reverse_iterator 120 pred_reverse_iterator; 121 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 122 const_pred_reverse_iterator; 123 typedef std::vector<MachineBasicBlock *>::reverse_iterator 124 succ_reverse_iterator; 125 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator 126 const_succ_reverse_iterator; 127 128 pred_iterator pred_begin() { return Predecessors.begin(); } 129 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 130 pred_iterator pred_end() { return Predecessors.end(); } 131 const_pred_iterator pred_end() const { return Predecessors.end(); } 132 pred_reverse_iterator pred_rbegin() 133 { return Predecessors.rbegin();} 134 const_pred_reverse_iterator pred_rbegin() const 135 { return Predecessors.rbegin();} 136 pred_reverse_iterator pred_rend() 137 { return Predecessors.rend(); } 138 const_pred_reverse_iterator pred_rend() const 139 { return Predecessors.rend(); } 140 unsigned pred_size() const { 141 return (unsigned)Predecessors.size(); 142 } 143 bool pred_empty() const { return Predecessors.empty(); } 144 succ_iterator succ_begin() { return Successors.begin(); } 145 const_succ_iterator succ_begin() const { return Successors.begin(); } 146 succ_iterator succ_end() { return Successors.end(); } 147 const_succ_iterator succ_end() const { return Successors.end(); } 148 succ_reverse_iterator succ_rbegin() 149 { return Successors.rbegin(); } 150 const_succ_reverse_iterator succ_rbegin() const 151 { return Successors.rbegin(); } 152 succ_reverse_iterator succ_rend() 153 { return Successors.rend(); } 154 const_succ_reverse_iterator succ_rend() const 155 { return Successors.rend(); } 156 unsigned succ_size() const { 157 return (unsigned)Successors.size(); 158 } 159 bool succ_empty() const { return Successors.empty(); } 160 161 // LiveIn management methods. 162 163 /// addLiveIn - Add the specified register as a live in. Note that it 164 /// is an error to add the same register to the same set more than once. 165 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); } 166 167 /// removeLiveIn - Remove the specified register from the live in set. 168 /// 169 void removeLiveIn(unsigned Reg); 170 171 /// isLiveIn - Return true if the specified register is in the live in set. 172 /// 173 bool isLiveIn(unsigned Reg) const; 174 175 // Iteration support for live in sets. These sets are kept in sorted 176 // order by their register number. 177 typedef std::vector<unsigned>::iterator livein_iterator; 178 typedef std::vector<unsigned>::const_iterator const_livein_iterator; 179 livein_iterator livein_begin() { return LiveIns.begin(); } 180 const_livein_iterator livein_begin() const { return LiveIns.begin(); } 181 livein_iterator livein_end() { return LiveIns.end(); } 182 const_livein_iterator livein_end() const { return LiveIns.end(); } 183 bool livein_empty() const { return LiveIns.empty(); } 184 185 /// getAlignment - Return alignment of the basic block. 186 /// 187 unsigned getAlignment() const { return Alignment; } 188 189 /// setAlignment - Set alignment of the basic block. 190 /// 191 void setAlignment(unsigned Align) { Alignment = Align; } 192 193 /// isLandingPad - Returns true if the block is a landing pad. That is 194 /// this basic block is entered via an exception handler. 195 bool isLandingPad() const { return IsLandingPad; } 196 197 /// setIsLandingPad - Indicates the block is a landing pad. That is 198 /// this basic block is entered via an exception handler. 199 void setIsLandingPad() { IsLandingPad = true; } 200 201 // Code Layout methods. 202 203 /// moveBefore/moveAfter - move 'this' block before or after the specified 204 /// block. This only moves the block, it does not modify the CFG or adjust 205 /// potential fall-throughs at the end of the block. 206 void moveBefore(MachineBasicBlock *NewAfter); 207 void moveAfter(MachineBasicBlock *NewBefore); 208 209 // Machine-CFG mutators 210 211 /// addSuccessor - Add succ as a successor of this MachineBasicBlock. 212 /// The Predecessors list of succ is automatically updated. 213 /// 214 void addSuccessor(MachineBasicBlock *succ); 215 216 /// removeSuccessor - Remove successor from the successors list of this 217 /// MachineBasicBlock. The Predecessors list of succ is automatically updated. 218 /// 219 void removeSuccessor(MachineBasicBlock *succ); 220 221 /// removeSuccessor - Remove specified successor from the successors list of 222 /// this MachineBasicBlock. The Predecessors list of succ is automatically 223 /// updated. Return the iterator to the element after the one removed. 224 /// 225 succ_iterator removeSuccessor(succ_iterator I); 226 227 /// transferSuccessors - Transfers all the successors from MBB to this 228 /// machine basic block (i.e., copies all the successors fromMBB and 229 /// remove all the successors fromBB). 230 void transferSuccessors(MachineBasicBlock *fromMBB); 231 232 /// isSuccessor - Return true if the specified MBB is a successor of this 233 /// block. 234 bool isSuccessor(MachineBasicBlock *MBB) const; 235 236 /// getFirstTerminator - returns an iterator to the first terminator 237 /// instruction of this basic block. If a terminator does not exist, 238 /// it returns end() 239 iterator getFirstTerminator(); 240 241 void pop_front() { Insts.pop_front(); } 242 void pop_back() { Insts.pop_back(); } 243 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 244 template<typename IT> 245 void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); } 246 iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); } 247 248 // erase - Remove the specified element or range from the instruction list. 249 // These functions delete any instructions removed. 250 // 251 iterator erase(iterator I) { return Insts.erase(I); } 252 iterator erase(iterator I, iterator E) { return Insts.erase(I, E); } 253 MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); } 254 void clear() { Insts.clear(); } 255 256 /// splice - Take a block of instructions from MBB 'Other' in the range [From, 257 /// To), and insert them into this MBB right before 'where'. 258 void splice(iterator where, MachineBasicBlock *Other, iterator From, 259 iterator To) { 260 Insts.splice(where, Other->Insts, From, To); 261 } 262 263 /// removeFromParent - This method unlinks 'this' from the containing 264 /// function, and returns it, but does not delete it. 265 MachineBasicBlock *removeFromParent(); 266 267 /// eraseFromParent - This method unlinks 'this' from the containing 268 /// function and deletes it. 269 void eraseFromParent(); 270 271 /// ReplaceUsesOfBlockWith - Given a machine basic block that branched to 272 /// 'Old', change the code and CFG so that it branches to 'New' instead. 273 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 274 275 /// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in 276 /// the CFG to be inserted. If we have proven that MBB can only branch to 277 /// DestA and DestB, remove any other MBB successors from the CFG. DestA and 278 /// DestB can be null. Besides DestA and DestB, retain other edges leading 279 /// to LandingPads (currently there can be only one; we don't check or require 280 /// that here). Note it is possible that DestA and/or DestB are LandingPads. 281 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, 282 MachineBasicBlock *DestB, 283 bool isCond); 284 285 // Debugging methods. 286 void dump() const; 287 void print(std::ostream &OS) const; 288 void print(std::ostream *OS) const { if (OS) print(*OS); } 289 290 /// getNumber - MachineBasicBlocks are uniquely numbered at the function 291 /// level, unless they're not in a MachineFunction yet, in which case this 292 /// will return -1. 293 /// 294 int getNumber() const { return Number; } 295 void setNumber(int N) { Number = N; } 296 297private: // Methods used to maintain doubly linked list of blocks... 298 friend struct ilist_traits<MachineBasicBlock>; 299 300 // Machine-CFG mutators 301 302 /// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock. 303 /// Don't do this unless you know what you're doing, because it doesn't 304 /// update pred's successors list. Use pred->addSuccessor instead. 305 /// 306 void addPredecessor(MachineBasicBlock *pred); 307 308 /// removePredecessor - Remove pred as a predecessor of this 309 /// MachineBasicBlock. Don't do this unless you know what you're 310 /// doing, because it doesn't update pred's successors list. Use 311 /// pred->removeSuccessor instead. 312 /// 313 void removePredecessor(MachineBasicBlock *pred); 314}; 315 316std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB); 317 318//===--------------------------------------------------------------------===// 319// GraphTraits specializations for machine basic block graphs (machine-CFGs) 320//===--------------------------------------------------------------------===// 321 322// Provide specializations of GraphTraits to be able to treat a 323// MachineFunction as a graph of MachineBasicBlocks... 324// 325 326template <> struct GraphTraits<MachineBasicBlock *> { 327 typedef MachineBasicBlock NodeType; 328 typedef MachineBasicBlock::succ_iterator ChildIteratorType; 329 330 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; } 331 static inline ChildIteratorType child_begin(NodeType *N) { 332 return N->succ_begin(); 333 } 334 static inline ChildIteratorType child_end(NodeType *N) { 335 return N->succ_end(); 336 } 337}; 338 339template <> struct GraphTraits<const MachineBasicBlock *> { 340 typedef const MachineBasicBlock NodeType; 341 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; 342 343 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; } 344 static inline ChildIteratorType child_begin(NodeType *N) { 345 return N->succ_begin(); 346 } 347 static inline ChildIteratorType child_end(NodeType *N) { 348 return N->succ_end(); 349 } 350}; 351 352// Provide specializations of GraphTraits to be able to treat a 353// MachineFunction as a graph of MachineBasicBlocks... and to walk it 354// in inverse order. Inverse order for a function is considered 355// to be when traversing the predecessor edges of a MBB 356// instead of the successor edges. 357// 358template <> struct GraphTraits<Inverse<MachineBasicBlock*> > { 359 typedef MachineBasicBlock NodeType; 360 typedef MachineBasicBlock::pred_iterator ChildIteratorType; 361 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) { 362 return G.Graph; 363 } 364 static inline ChildIteratorType child_begin(NodeType *N) { 365 return N->pred_begin(); 366 } 367 static inline ChildIteratorType child_end(NodeType *N) { 368 return N->pred_end(); 369 } 370}; 371 372template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > { 373 typedef const MachineBasicBlock NodeType; 374 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; 375 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) { 376 return G.Graph; 377 } 378 static inline ChildIteratorType child_begin(NodeType *N) { 379 return N->pred_begin(); 380 } 381 static inline ChildIteratorType child_end(NodeType *N) { 382 return N->pred_end(); 383 } 384}; 385 386} // End llvm namespace 387 388#endif 389