1 //===- llvm/CodeGen/MachineBasicBlock.h -------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Collect the sequence of machine instructions for a basic block. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H 14 #define LLVM_CODEGEN_MACHINEBASICBLOCK_H 15 16 #include "llvm/ADT/GraphTraits.h" 17 #include "llvm/ADT/SparseBitVector.h" 18 #include "llvm/ADT/ilist.h" 19 #include "llvm/ADT/iterator_range.h" 20 #include "llvm/CodeGen/MachineInstr.h" 21 #include "llvm/CodeGen/MachineInstrBundleIterator.h" 22 #include "llvm/IR/DebugLoc.h" 23 #include "llvm/MC/LaneBitmask.h" 24 #include "llvm/Support/BranchProbability.h" 25 #include <cassert> 26 #include <cstdint> 27 #include <iterator> 28 #include <string> 29 #include <vector> 30 31 namespace llvm { 32 33 class BasicBlock; 34 class MachineFunction; 35 class MCSymbol; 36 class ModuleSlotTracker; 37 class Pass; 38 class Printable; 39 class SlotIndexes; 40 class StringRef; 41 class raw_ostream; 42 class LiveIntervals; 43 class TargetRegisterClass; 44 class TargetRegisterInfo; 45 46 // This structure uniquely identifies a basic block section. 47 // Possible values are 48 // {Type: Default, Number: (unsigned)} (These are regular section IDs) 49 // {Type: Exception, Number: 0} (ExceptionSectionID) 50 // {Type: Cold, Number: 0} (ColdSectionID) 51 struct MBBSectionID { 52 enum SectionType { 53 Default = 0, // Regular section (these sections are distinguished by the 54 // Number field). 55 Exception, // Special section type for exception handling blocks 56 Cold, // Special section type for cold blocks 57 } Type; 58 unsigned Number; 59 60 MBBSectionID(unsigned N) : Type(Default), Number(N) {} 61 62 // Special unique sections for cold and exception blocks. 63 const static MBBSectionID ColdSectionID; 64 const static MBBSectionID ExceptionSectionID; 65 66 bool operator==(const MBBSectionID &Other) const { 67 return Type == Other.Type && Number == Other.Number; 68 } 69 70 bool operator!=(const MBBSectionID &Other) const { return !(*this == Other); } 71 72 private: 73 // This is only used to construct the special cold and exception sections. 74 MBBSectionID(SectionType T) : Type(T), Number(0) {} 75 }; 76 77 template <> struct ilist_traits<MachineInstr> { 78 private: 79 friend class MachineBasicBlock; // Set by the owning MachineBasicBlock. 80 81 MachineBasicBlock *Parent; 82 83 using instr_iterator = 84 simple_ilist<MachineInstr, ilist_sentinel_tracking<true>>::iterator; 85 86 public: 87 void addNodeToList(MachineInstr *N); 88 void removeNodeFromList(MachineInstr *N); 89 void transferNodesFromList(ilist_traits &FromList, instr_iterator First, 90 instr_iterator Last); 91 void deleteNode(MachineInstr *MI); 92 }; 93 94 class MachineBasicBlock 95 : public ilist_node_with_parent<MachineBasicBlock, MachineFunction> { 96 public: 97 /// Pair of physical register and lane mask. 98 /// This is not simply a std::pair typedef because the members should be named 99 /// clearly as they both have an integer type. 100 struct RegisterMaskPair { 101 public: 102 MCPhysReg PhysReg; 103 LaneBitmask LaneMask; 104 105 RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask) 106 : PhysReg(PhysReg), LaneMask(LaneMask) {} 107 }; 108 109 private: 110 using Instructions = ilist<MachineInstr, ilist_sentinel_tracking<true>>; 111 112 const BasicBlock *BB; 113 int Number; 114 MachineFunction *xParent; 115 Instructions Insts; 116 117 /// Keep track of the predecessor / successor basic blocks. 118 std::vector<MachineBasicBlock *> Predecessors; 119 std::vector<MachineBasicBlock *> Successors; 120 121 /// Keep track of the probabilities to the successors. This vector has the 122 /// same order as Successors, or it is empty if we don't use it (disable 123 /// optimization). 124 std::vector<BranchProbability> Probs; 125 using probability_iterator = std::vector<BranchProbability>::iterator; 126 using const_probability_iterator = 127 std::vector<BranchProbability>::const_iterator; 128 129 Optional<uint64_t> IrrLoopHeaderWeight; 130 131 /// Keep track of the physical registers that are livein of the basicblock. 132 using LiveInVector = std::vector<RegisterMaskPair>; 133 LiveInVector LiveIns; 134 135 /// Alignment of the basic block. One if the basic block does not need to be 136 /// aligned. 137 Align Alignment; 138 /// Maximum amount of bytes that can be added to align the basic block. If the 139 /// alignment cannot be reached in this many bytes, no bytes are emitted. 140 /// Zero to represent no maximum. 141 unsigned MaxBytesForAlignment = 0; 142 143 /// Indicate that this basic block is entered via an exception handler. 144 bool IsEHPad = false; 145 146 /// Indicate that this basic block is potentially the target of an indirect 147 /// branch. 148 bool AddressTaken = false; 149 150 /// Indicate that this basic block needs its symbol be emitted regardless of 151 /// whether the flow just falls-through to it. 152 bool LabelMustBeEmitted = false; 153 154 /// Indicate that this basic block is the entry block of an EH scope, i.e., 155 /// the block that used to have a catchpad or cleanuppad instruction in the 156 /// LLVM IR. 157 bool IsEHScopeEntry = false; 158 159 /// Indicates if this is a target block of a catchret. 160 bool IsEHCatchretTarget = false; 161 162 /// Indicate that this basic block is the entry block of an EH funclet. 163 bool IsEHFuncletEntry = false; 164 165 /// Indicate that this basic block is the entry block of a cleanup funclet. 166 bool IsCleanupFuncletEntry = false; 167 168 /// With basic block sections, this stores the Section ID of the basic block. 169 MBBSectionID SectionID{0}; 170 171 // Indicate that this basic block begins a section. 172 bool IsBeginSection = false; 173 174 // Indicate that this basic block ends a section. 175 bool IsEndSection = false; 176 177 /// Indicate that this basic block is the indirect dest of an INLINEASM_BR. 178 bool IsInlineAsmBrIndirectTarget = false; 179 180 /// since getSymbol is a relatively heavy-weight operation, the symbol 181 /// is only computed once and is cached. 182 mutable MCSymbol *CachedMCSymbol = nullptr; 183 184 /// Cached MCSymbol for this block (used if IsEHCatchRetTarget). 185 mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr; 186 187 /// Marks the end of the basic block. Used during basic block sections to 188 /// calculate the size of the basic block, or the BB section ending with it. 189 mutable MCSymbol *CachedEndMCSymbol = nullptr; 190 191 // Intrusive list support 192 MachineBasicBlock() = default; 193 194 explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB); 195 196 ~MachineBasicBlock(); 197 198 // MachineBasicBlocks are allocated and owned by MachineFunction. 199 friend class MachineFunction; 200 201 public: 202 /// Return the LLVM basic block that this instance corresponded to originally. 203 /// Note that this may be NULL if this instance does not correspond directly 204 /// to an LLVM basic block. 205 const BasicBlock *getBasicBlock() const { return BB; } 206 207 /// Remove the reference to the underlying IR BasicBlock. This is for 208 /// reduction tools and should generally not be used. 209 void clearBasicBlock() { 210 BB = nullptr; 211 } 212 213 /// Return the name of the corresponding LLVM basic block, or an empty string. 214 StringRef getName() const; 215 216 /// Return a formatted string to identify this block and its parent function. 217 std::string getFullName() const; 218 219 /// Test whether this block is potentially the target of an indirect branch. 220 bool hasAddressTaken() const { return AddressTaken; } 221 222 /// Set this block to reflect that it potentially is the target of an indirect 223 /// branch. 224 void setHasAddressTaken() { AddressTaken = true; } 225 226 /// Test whether this block must have its label emitted. 227 bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; } 228 229 /// Set this block to reflect that, regardless how we flow to it, we need 230 /// its label be emitted. 231 void setLabelMustBeEmitted() { LabelMustBeEmitted = true; } 232 233 /// Return the MachineFunction containing this basic block. 234 const MachineFunction *getParent() const { return xParent; } 235 MachineFunction *getParent() { return xParent; } 236 237 using instr_iterator = Instructions::iterator; 238 using const_instr_iterator = Instructions::const_iterator; 239 using reverse_instr_iterator = Instructions::reverse_iterator; 240 using const_reverse_instr_iterator = Instructions::const_reverse_iterator; 241 242 using iterator = MachineInstrBundleIterator<MachineInstr>; 243 using const_iterator = MachineInstrBundleIterator<const MachineInstr>; 244 using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>; 245 using const_reverse_iterator = 246 MachineInstrBundleIterator<const MachineInstr, true>; 247 248 unsigned size() const { return (unsigned)Insts.size(); } 249 bool sizeWithoutDebugLargerThan(unsigned Limit) const; 250 bool empty() const { return Insts.empty(); } 251 252 MachineInstr &instr_front() { return Insts.front(); } 253 MachineInstr &instr_back() { return Insts.back(); } 254 const MachineInstr &instr_front() const { return Insts.front(); } 255 const MachineInstr &instr_back() const { return Insts.back(); } 256 257 MachineInstr &front() { return Insts.front(); } 258 MachineInstr &back() { return *--end(); } 259 const MachineInstr &front() const { return Insts.front(); } 260 const MachineInstr &back() const { return *--end(); } 261 262 instr_iterator instr_begin() { return Insts.begin(); } 263 const_instr_iterator instr_begin() const { return Insts.begin(); } 264 instr_iterator instr_end() { return Insts.end(); } 265 const_instr_iterator instr_end() const { return Insts.end(); } 266 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); } 267 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); } 268 reverse_instr_iterator instr_rend () { return Insts.rend(); } 269 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); } 270 271 using instr_range = iterator_range<instr_iterator>; 272 using const_instr_range = iterator_range<const_instr_iterator>; 273 instr_range instrs() { return instr_range(instr_begin(), instr_end()); } 274 const_instr_range instrs() const { 275 return const_instr_range(instr_begin(), instr_end()); 276 } 277 278 iterator begin() { return instr_begin(); } 279 const_iterator begin() const { return instr_begin(); } 280 iterator end () { return instr_end(); } 281 const_iterator end () const { return instr_end(); } 282 reverse_iterator rbegin() { 283 return reverse_iterator::getAtBundleBegin(instr_rbegin()); 284 } 285 const_reverse_iterator rbegin() const { 286 return const_reverse_iterator::getAtBundleBegin(instr_rbegin()); 287 } 288 reverse_iterator rend() { return reverse_iterator(instr_rend()); } 289 const_reverse_iterator rend() const { 290 return const_reverse_iterator(instr_rend()); 291 } 292 293 /// Support for MachineInstr::getNextNode(). 294 static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) { 295 return &MachineBasicBlock::Insts; 296 } 297 298 inline iterator_range<iterator> terminators() { 299 return make_range(getFirstTerminator(), end()); 300 } 301 inline iterator_range<const_iterator> terminators() const { 302 return make_range(getFirstTerminator(), end()); 303 } 304 305 /// Returns a range that iterates over the phis in the basic block. 306 inline iterator_range<iterator> phis() { 307 return make_range(begin(), getFirstNonPHI()); 308 } 309 inline iterator_range<const_iterator> phis() const { 310 return const_cast<MachineBasicBlock *>(this)->phis(); 311 } 312 313 // Machine-CFG iterators 314 using pred_iterator = std::vector<MachineBasicBlock *>::iterator; 315 using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator; 316 using succ_iterator = std::vector<MachineBasicBlock *>::iterator; 317 using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator; 318 using pred_reverse_iterator = 319 std::vector<MachineBasicBlock *>::reverse_iterator; 320 using const_pred_reverse_iterator = 321 std::vector<MachineBasicBlock *>::const_reverse_iterator; 322 using succ_reverse_iterator = 323 std::vector<MachineBasicBlock *>::reverse_iterator; 324 using const_succ_reverse_iterator = 325 std::vector<MachineBasicBlock *>::const_reverse_iterator; 326 pred_iterator pred_begin() { return Predecessors.begin(); } 327 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 328 pred_iterator pred_end() { return Predecessors.end(); } 329 const_pred_iterator pred_end() const { return Predecessors.end(); } 330 pred_reverse_iterator pred_rbegin() 331 { return Predecessors.rbegin();} 332 const_pred_reverse_iterator pred_rbegin() const 333 { return Predecessors.rbegin();} 334 pred_reverse_iterator pred_rend() 335 { return Predecessors.rend(); } 336 const_pred_reverse_iterator pred_rend() const 337 { return Predecessors.rend(); } 338 unsigned pred_size() const { 339 return (unsigned)Predecessors.size(); 340 } 341 bool pred_empty() const { return Predecessors.empty(); } 342 succ_iterator succ_begin() { return Successors.begin(); } 343 const_succ_iterator succ_begin() const { return Successors.begin(); } 344 succ_iterator succ_end() { return Successors.end(); } 345 const_succ_iterator succ_end() const { return Successors.end(); } 346 succ_reverse_iterator succ_rbegin() 347 { return Successors.rbegin(); } 348 const_succ_reverse_iterator succ_rbegin() const 349 { return Successors.rbegin(); } 350 succ_reverse_iterator succ_rend() 351 { return Successors.rend(); } 352 const_succ_reverse_iterator succ_rend() const 353 { return Successors.rend(); } 354 unsigned succ_size() const { 355 return (unsigned)Successors.size(); 356 } 357 bool succ_empty() const { return Successors.empty(); } 358 359 inline iterator_range<pred_iterator> predecessors() { 360 return make_range(pred_begin(), pred_end()); 361 } 362 inline iterator_range<const_pred_iterator> predecessors() const { 363 return make_range(pred_begin(), pred_end()); 364 } 365 inline iterator_range<succ_iterator> successors() { 366 return make_range(succ_begin(), succ_end()); 367 } 368 inline iterator_range<const_succ_iterator> successors() const { 369 return make_range(succ_begin(), succ_end()); 370 } 371 372 // LiveIn management methods. 373 374 /// Adds the specified register as a live in. Note that it is an error to add 375 /// the same register to the same set more than once unless the intention is 376 /// to call sortUniqueLiveIns after all registers are added. 377 void addLiveIn(MCRegister PhysReg, 378 LaneBitmask LaneMask = LaneBitmask::getAll()) { 379 LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask)); 380 } 381 void addLiveIn(const RegisterMaskPair &RegMaskPair) { 382 LiveIns.push_back(RegMaskPair); 383 } 384 385 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do 386 /// this than repeatedly calling isLiveIn before calling addLiveIn for every 387 /// LiveIn insertion. 388 void sortUniqueLiveIns(); 389 390 /// Clear live in list. 391 void clearLiveIns(); 392 393 /// Add PhysReg as live in to this block, and ensure that there is a copy of 394 /// PhysReg to a virtual register of class RC. Return the virtual register 395 /// that is a copy of the live in PhysReg. 396 Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC); 397 398 /// Remove the specified register from the live in set. 399 void removeLiveIn(MCPhysReg Reg, 400 LaneBitmask LaneMask = LaneBitmask::getAll()); 401 402 /// Return true if the specified register is in the live in set. 403 bool isLiveIn(MCPhysReg Reg, 404 LaneBitmask LaneMask = LaneBitmask::getAll()) const; 405 406 // Iteration support for live in sets. These sets are kept in sorted 407 // order by their register number. 408 using livein_iterator = LiveInVector::const_iterator; 409 410 /// Unlike livein_begin, this method does not check that the liveness 411 /// information is accurate. Still for debug purposes it may be useful 412 /// to have iterators that won't assert if the liveness information 413 /// is not current. 414 livein_iterator livein_begin_dbg() const { return LiveIns.begin(); } 415 iterator_range<livein_iterator> liveins_dbg() const { 416 return make_range(livein_begin_dbg(), livein_end()); 417 } 418 419 livein_iterator livein_begin() const; 420 livein_iterator livein_end() const { return LiveIns.end(); } 421 bool livein_empty() const { return LiveIns.empty(); } 422 iterator_range<livein_iterator> liveins() const { 423 return make_range(livein_begin(), livein_end()); 424 } 425 426 /// Remove entry from the livein set and return iterator to the next. 427 livein_iterator removeLiveIn(livein_iterator I); 428 429 class liveout_iterator { 430 public: 431 using iterator_category = std::input_iterator_tag; 432 using difference_type = std::ptrdiff_t; 433 using value_type = RegisterMaskPair; 434 using pointer = const RegisterMaskPair *; 435 using reference = const RegisterMaskPair &; 436 437 liveout_iterator(const MachineBasicBlock &MBB, MCPhysReg ExceptionPointer, 438 MCPhysReg ExceptionSelector, bool End) 439 : ExceptionPointer(ExceptionPointer), 440 ExceptionSelector(ExceptionSelector), BlockI(MBB.succ_begin()), 441 BlockEnd(MBB.succ_end()) { 442 if (End) 443 BlockI = BlockEnd; 444 else if (BlockI != BlockEnd) { 445 LiveRegI = (*BlockI)->livein_begin(); 446 if (!advanceToValidPosition()) 447 return; 448 if (LiveRegI->PhysReg == ExceptionPointer || 449 LiveRegI->PhysReg == ExceptionSelector) 450 ++(*this); 451 } 452 } 453 454 liveout_iterator &operator++() { 455 do { 456 ++LiveRegI; 457 if (!advanceToValidPosition()) 458 return *this; 459 } while ((*BlockI)->isEHPad() && 460 (LiveRegI->PhysReg == ExceptionPointer || 461 LiveRegI->PhysReg == ExceptionSelector)); 462 return *this; 463 } 464 465 liveout_iterator operator++(int) { 466 liveout_iterator Tmp = *this; 467 ++(*this); 468 return Tmp; 469 } 470 471 reference operator*() const { 472 return *LiveRegI; 473 } 474 475 pointer operator->() const { 476 return &*LiveRegI; 477 } 478 479 bool operator==(const liveout_iterator &RHS) const { 480 if (BlockI != BlockEnd) 481 return BlockI == RHS.BlockI && LiveRegI == RHS.LiveRegI; 482 return RHS.BlockI == BlockEnd; 483 } 484 485 bool operator!=(const liveout_iterator &RHS) const { 486 return !(*this == RHS); 487 } 488 private: 489 bool advanceToValidPosition() { 490 if (LiveRegI != (*BlockI)->livein_end()) 491 return true; 492 493 do { 494 ++BlockI; 495 } while (BlockI != BlockEnd && (*BlockI)->livein_empty()); 496 if (BlockI == BlockEnd) 497 return false; 498 499 LiveRegI = (*BlockI)->livein_begin(); 500 return true; 501 } 502 503 MCPhysReg ExceptionPointer, ExceptionSelector; 504 const_succ_iterator BlockI; 505 const_succ_iterator BlockEnd; 506 livein_iterator LiveRegI; 507 }; 508 509 /// Iterator scanning successor basic blocks' liveins to determine the 510 /// registers potentially live at the end of this block. There may be 511 /// duplicates or overlapping registers in the list returned. 512 liveout_iterator liveout_begin() const; 513 liveout_iterator liveout_end() const { 514 return liveout_iterator(*this, 0, 0, true); 515 } 516 iterator_range<liveout_iterator> liveouts() const { 517 return make_range(liveout_begin(), liveout_end()); 518 } 519 520 /// Get the clobber mask for the start of this basic block. Funclets use this 521 /// to prevent register allocation across funclet transitions. 522 const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const; 523 524 /// Get the clobber mask for the end of the basic block. 525 /// \see getBeginClobberMask() 526 const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const; 527 528 /// Return alignment of the basic block. 529 Align getAlignment() const { return Alignment; } 530 531 /// Set alignment of the basic block. 532 void setAlignment(Align A) { Alignment = A; } 533 534 void setAlignment(Align A, unsigned MaxBytes) { 535 setAlignment(A); 536 setMaxBytesForAlignment(MaxBytes); 537 } 538 539 /// Return the maximum amount of padding allowed for aligning the basic block. 540 unsigned getMaxBytesForAlignment() const { return MaxBytesForAlignment; } 541 542 /// Set the maximum amount of padding allowed for aligning the basic block 543 void setMaxBytesForAlignment(unsigned MaxBytes) { 544 MaxBytesForAlignment = MaxBytes; 545 } 546 547 /// Returns true if the block is a landing pad. That is this basic block is 548 /// entered via an exception handler. 549 bool isEHPad() const { return IsEHPad; } 550 551 /// Indicates the block is a landing pad. That is this basic block is entered 552 /// via an exception handler. 553 void setIsEHPad(bool V = true) { IsEHPad = V; } 554 555 bool hasEHPadSuccessor() const; 556 557 /// Returns true if this is the entry block of the function. 558 bool isEntryBlock() const; 559 560 /// Returns true if this is the entry block of an EH scope, i.e., the block 561 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 562 bool isEHScopeEntry() const { return IsEHScopeEntry; } 563 564 /// Indicates if this is the entry block of an EH scope, i.e., the block that 565 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 566 void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; } 567 568 /// Returns true if this is a target block of a catchret. 569 bool isEHCatchretTarget() const { return IsEHCatchretTarget; } 570 571 /// Indicates if this is a target block of a catchret. 572 void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; } 573 574 /// Returns true if this is the entry block of an EH funclet. 575 bool isEHFuncletEntry() const { return IsEHFuncletEntry; } 576 577 /// Indicates if this is the entry block of an EH funclet. 578 void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; } 579 580 /// Returns true if this is the entry block of a cleanup funclet. 581 bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; } 582 583 /// Indicates if this is the entry block of a cleanup funclet. 584 void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; } 585 586 /// Returns true if this block begins any section. 587 bool isBeginSection() const { return IsBeginSection; } 588 589 /// Returns true if this block ends any section. 590 bool isEndSection() const { return IsEndSection; } 591 592 void setIsBeginSection(bool V = true) { IsBeginSection = V; } 593 594 void setIsEndSection(bool V = true) { IsEndSection = V; } 595 596 /// Returns the section ID of this basic block. 597 MBBSectionID getSectionID() const { return SectionID; } 598 599 /// Returns the unique section ID number of this basic block. 600 unsigned getSectionIDNum() const { 601 return ((unsigned)MBBSectionID::SectionType::Cold) - 602 ((unsigned)SectionID.Type) + SectionID.Number; 603 } 604 605 /// Sets the section ID for this basic block. 606 void setSectionID(MBBSectionID V) { SectionID = V; } 607 608 /// Returns the MCSymbol marking the end of this basic block. 609 MCSymbol *getEndSymbol() const; 610 611 /// Returns true if this block may have an INLINEASM_BR (overestimate, by 612 /// checking if any of the successors are indirect targets of any inlineasm_br 613 /// in the function). 614 bool mayHaveInlineAsmBr() const; 615 616 /// Returns true if this is the indirect dest of an INLINEASM_BR. 617 bool isInlineAsmBrIndirectTarget() const { 618 return IsInlineAsmBrIndirectTarget; 619 } 620 621 /// Indicates if this is the indirect dest of an INLINEASM_BR. 622 void setIsInlineAsmBrIndirectTarget(bool V = true) { 623 IsInlineAsmBrIndirectTarget = V; 624 } 625 626 /// Returns true if it is legal to hoist instructions into this block. 627 bool isLegalToHoistInto() const; 628 629 // Code Layout methods. 630 631 /// Move 'this' block before or after the specified block. This only moves 632 /// the block, it does not modify the CFG or adjust potential fall-throughs at 633 /// the end of the block. 634 void moveBefore(MachineBasicBlock *NewAfter); 635 void moveAfter(MachineBasicBlock *NewBefore); 636 637 /// Returns true if this and MBB belong to the same section. 638 bool sameSection(const MachineBasicBlock *MBB) const { 639 return getSectionID() == MBB->getSectionID(); 640 } 641 642 /// Update the terminator instructions in block to account for changes to 643 /// block layout which may have been made. PreviousLayoutSuccessor should be 644 /// set to the block which may have been used as fallthrough before the block 645 /// layout was modified. If the block previously fell through to that block, 646 /// it may now need a branch. If it previously branched to another block, it 647 /// may now be able to fallthrough to the current layout successor. 648 void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor); 649 650 // Machine-CFG mutators 651 652 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 653 /// of Succ is automatically updated. PROB parameter is stored in 654 /// Probabilities list. The default probability is set as unknown. Mixing 655 /// known and unknown probabilities in successor list is not allowed. When all 656 /// successors have unknown probabilities, 1 / N is returned as the 657 /// probability for each successor, where N is the number of successors. 658 /// 659 /// Note that duplicate Machine CFG edges are not allowed. 660 void addSuccessor(MachineBasicBlock *Succ, 661 BranchProbability Prob = BranchProbability::getUnknown()); 662 663 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 664 /// of Succ is automatically updated. The probability is not provided because 665 /// BPI is not available (e.g. -O0 is used), in which case edge probabilities 666 /// won't be used. Using this interface can save some space. 667 void addSuccessorWithoutProb(MachineBasicBlock *Succ); 668 669 /// Set successor probability of a given iterator. 670 void setSuccProbability(succ_iterator I, BranchProbability Prob); 671 672 /// Normalize probabilities of all successors so that the sum of them becomes 673 /// one. This is usually done when the current update on this MBB is done, and 674 /// the sum of its successors' probabilities is not guaranteed to be one. The 675 /// user is responsible for the correct use of this function. 676 /// MBB::removeSuccessor() has an option to do this automatically. 677 void normalizeSuccProbs() { 678 BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end()); 679 } 680 681 /// Validate successors' probabilities and check if the sum of them is 682 /// approximate one. This only works in DEBUG mode. 683 void validateSuccProbs() const; 684 685 /// Remove successor from the successors list of this MachineBasicBlock. The 686 /// Predecessors list of Succ is automatically updated. 687 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 688 /// after the successor is removed. 689 void removeSuccessor(MachineBasicBlock *Succ, 690 bool NormalizeSuccProbs = false); 691 692 /// Remove specified successor from the successors list of this 693 /// MachineBasicBlock. The Predecessors list of Succ is automatically updated. 694 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 695 /// after the successor is removed. 696 /// Return the iterator to the element after the one removed. 697 succ_iterator removeSuccessor(succ_iterator I, 698 bool NormalizeSuccProbs = false); 699 700 /// Replace successor OLD with NEW and update probability info. 701 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New); 702 703 /// Copy a successor (and any probability info) from original block to this 704 /// block's. Uses an iterator into the original blocks successors. 705 /// 706 /// This is useful when doing a partial clone of successors. Afterward, the 707 /// probabilities may need to be normalized. 708 void copySuccessor(MachineBasicBlock *Orig, succ_iterator I); 709 710 /// Split the old successor into old plus new and updates the probability 711 /// info. 712 void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New, 713 bool NormalizeSuccProbs = false); 714 715 /// Transfers all the successors from MBB to this machine basic block (i.e., 716 /// copies all the successors FromMBB and remove all the successors from 717 /// FromMBB). 718 void transferSuccessors(MachineBasicBlock *FromMBB); 719 720 /// Transfers all the successors, as in transferSuccessors, and update PHI 721 /// operands in the successor blocks which refer to FromMBB to refer to this. 722 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB); 723 724 /// Return true if any of the successors have probabilities attached to them. 725 bool hasSuccessorProbabilities() const { return !Probs.empty(); } 726 727 /// Return true if the specified MBB is a predecessor of this block. 728 bool isPredecessor(const MachineBasicBlock *MBB) const; 729 730 /// Return true if the specified MBB is a successor of this block. 731 bool isSuccessor(const MachineBasicBlock *MBB) const; 732 733 /// Return true if the specified MBB will be emitted immediately after this 734 /// block, such that if this block exits by falling through, control will 735 /// transfer to the specified MBB. Note that MBB need not be a successor at 736 /// all, for example if this block ends with an unconditional branch to some 737 /// other block. 738 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; 739 740 /// Return the successor of this block if it has a single successor. 741 /// Otherwise return a null pointer. 742 /// 743 const MachineBasicBlock *getSingleSuccessor() const; 744 MachineBasicBlock *getSingleSuccessor() { 745 return const_cast<MachineBasicBlock *>( 746 static_cast<const MachineBasicBlock *>(this)->getSingleSuccessor()); 747 } 748 749 /// Return the fallthrough block if the block can implicitly 750 /// transfer control to the block after it by falling off the end of 751 /// it. This should return null if it can reach the block after 752 /// it, but it uses an explicit branch to do so (e.g., a table 753 /// jump). Non-null return is a conservative answer. 754 MachineBasicBlock *getFallThrough(); 755 756 /// Return true if the block can implicitly transfer control to the 757 /// block after it by falling off the end of it. This should return 758 /// false if it can reach the block after it, but it uses an 759 /// explicit branch to do so (e.g., a table jump). True is a 760 /// conservative answer. 761 bool canFallThrough(); 762 763 /// Returns a pointer to the first instruction in this block that is not a 764 /// PHINode instruction. When adding instructions to the beginning of the 765 /// basic block, they should be added before the returned value, not before 766 /// the first instruction, which might be PHI. 767 /// Returns end() is there's no non-PHI instruction. 768 iterator getFirstNonPHI(); 769 770 /// Return the first instruction in MBB after I that is not a PHI or a label. 771 /// This is the correct point to insert lowered copies at the beginning of a 772 /// basic block that must be before any debugging information. 773 iterator SkipPHIsAndLabels(iterator I); 774 775 /// Return the first instruction in MBB after I that is not a PHI, label or 776 /// debug. This is the correct point to insert copies at the beginning of a 777 /// basic block. 778 iterator SkipPHIsLabelsAndDebug(iterator I, bool SkipPseudoOp = true); 779 780 /// Returns an iterator to the first terminator instruction of this basic 781 /// block. If a terminator does not exist, it returns end(). 782 iterator getFirstTerminator(); 783 const_iterator getFirstTerminator() const { 784 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator(); 785 } 786 787 /// Same getFirstTerminator but it ignores bundles and return an 788 /// instr_iterator instead. 789 instr_iterator getFirstInstrTerminator(); 790 791 /// Returns an iterator to the first non-debug instruction in the basic block, 792 /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true. 793 /// Pseudo probes are like debug instructions which do not turn into real 794 /// machine code. We try to use the function to skip both debug instructions 795 /// and pseudo probe operations to avoid API proliferation. This should work 796 /// most of the time when considering optimizing the rest of code in the 797 /// block, except for certain cases where pseudo probes are designed to block 798 /// the optimizations. For example, code merge like optimizations are supposed 799 /// to be blocked by pseudo probes for better AutoFDO profile quality. 800 /// Therefore, they should be considered as a valid instruction when this 801 /// function is called in a context of such optimizations. On the other hand, 802 /// \c SkipPseudoOp should be true when it's used in optimizations that 803 /// unlikely hurt profile quality, e.g., without block merging. The default 804 /// value of \c SkipPseudoOp is set to true to maximize code quality in 805 /// general, with an explict false value passed in in a few places like branch 806 /// folding and if-conversion to favor profile quality. 807 iterator getFirstNonDebugInstr(bool SkipPseudoOp = true); 808 const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const { 809 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr( 810 SkipPseudoOp); 811 } 812 813 /// Returns an iterator to the last non-debug instruction in the basic block, 814 /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true. 815 /// Pseudo probes are like debug instructions which do not turn into real 816 /// machine code. We try to use the function to skip both debug instructions 817 /// and pseudo probe operations to avoid API proliferation. This should work 818 /// most of the time when considering optimizing the rest of code in the 819 /// block, except for certain cases where pseudo probes are designed to block 820 /// the optimizations. For example, code merge like optimizations are supposed 821 /// to be blocked by pseudo probes for better AutoFDO profile quality. 822 /// Therefore, they should be considered as a valid instruction when this 823 /// function is called in a context of such optimizations. On the other hand, 824 /// \c SkipPseudoOp should be true when it's used in optimizations that 825 /// unlikely hurt profile quality, e.g., without block merging. The default 826 /// value of \c SkipPseudoOp is set to true to maximize code quality in 827 /// general, with an explict false value passed in in a few places like branch 828 /// folding and if-conversion to favor profile quality. 829 iterator getLastNonDebugInstr(bool SkipPseudoOp = true); 830 const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const { 831 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr( 832 SkipPseudoOp); 833 } 834 835 /// Convenience function that returns true if the block ends in a return 836 /// instruction. 837 bool isReturnBlock() const { 838 return !empty() && back().isReturn(); 839 } 840 841 /// Convenience function that returns true if the bock ends in a EH scope 842 /// return instruction. 843 bool isEHScopeReturnBlock() const { 844 return !empty() && back().isEHScopeReturn(); 845 } 846 847 /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be 848 /// inserted after this block, and all instructions after \p SplitInst moved 849 /// to it (\p SplitInst will be in the original block). If \p LIS is provided, 850 /// LiveIntervals will be appropriately updated. \return the newly inserted 851 /// block. 852 /// 853 /// If \p UpdateLiveIns is true, this will ensure the live ins list is 854 /// accurate, including for physreg uses/defs in the original block. 855 MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true, 856 LiveIntervals *LIS = nullptr); 857 858 /// Split the critical edge from this block to the given successor block, and 859 /// return the newly created block, or null if splitting is not possible. 860 /// 861 /// This function updates LiveVariables, MachineDominatorTree, and 862 /// MachineLoopInfo, as applicable. 863 MachineBasicBlock * 864 SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P, 865 std::vector<SparseBitVector<>> *LiveInSets = nullptr); 866 867 /// Check if the edge between this block and the given successor \p 868 /// Succ, can be split. If this returns true a subsequent call to 869 /// SplitCriticalEdge is guaranteed to return a valid basic block if 870 /// no changes occurred in the meantime. 871 bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; 872 873 void pop_front() { Insts.pop_front(); } 874 void pop_back() { Insts.pop_back(); } 875 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 876 877 /// Insert MI into the instruction list before I, possibly inside a bundle. 878 /// 879 /// If the insertion point is inside a bundle, MI will be added to the bundle, 880 /// otherwise MI will not be added to any bundle. That means this function 881 /// alone can't be used to prepend or append instructions to bundles. See 882 /// MIBundleBuilder::insert() for a more reliable way of doing that. 883 instr_iterator insert(instr_iterator I, MachineInstr *M); 884 885 /// Insert a range of instructions into the instruction list before I. 886 template<typename IT> 887 void insert(iterator I, IT S, IT E) { 888 assert((I == end() || I->getParent() == this) && 889 "iterator points outside of basic block"); 890 Insts.insert(I.getInstrIterator(), S, E); 891 } 892 893 /// Insert MI into the instruction list before I. 894 iterator insert(iterator I, MachineInstr *MI) { 895 assert((I == end() || I->getParent() == this) && 896 "iterator points outside of basic block"); 897 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 898 "Cannot insert instruction with bundle flags"); 899 return Insts.insert(I.getInstrIterator(), MI); 900 } 901 902 /// Insert MI into the instruction list after I. 903 iterator insertAfter(iterator I, MachineInstr *MI) { 904 assert((I == end() || I->getParent() == this) && 905 "iterator points outside of basic block"); 906 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 907 "Cannot insert instruction with bundle flags"); 908 return Insts.insertAfter(I.getInstrIterator(), MI); 909 } 910 911 /// If I is bundled then insert MI into the instruction list after the end of 912 /// the bundle, otherwise insert MI immediately after I. 913 instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) { 914 assert((I == instr_end() || I->getParent() == this) && 915 "iterator points outside of basic block"); 916 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 917 "Cannot insert instruction with bundle flags"); 918 while (I->isBundledWithSucc()) 919 ++I; 920 return Insts.insertAfter(I, MI); 921 } 922 923 /// Remove an instruction from the instruction list and delete it. 924 /// 925 /// If the instruction is part of a bundle, the other instructions in the 926 /// bundle will still be bundled after removing the single instruction. 927 instr_iterator erase(instr_iterator I); 928 929 /// Remove an instruction from the instruction list and delete it. 930 /// 931 /// If the instruction is part of a bundle, the other instructions in the 932 /// bundle will still be bundled after removing the single instruction. 933 instr_iterator erase_instr(MachineInstr *I) { 934 return erase(instr_iterator(I)); 935 } 936 937 /// Remove a range of instructions from the instruction list and delete them. 938 iterator erase(iterator I, iterator E) { 939 return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); 940 } 941 942 /// Remove an instruction or bundle from the instruction list and delete it. 943 /// 944 /// If I points to a bundle of instructions, they are all erased. 945 iterator erase(iterator I) { 946 return erase(I, std::next(I)); 947 } 948 949 /// Remove an instruction from the instruction list and delete it. 950 /// 951 /// If I is the head of a bundle of instructions, the whole bundle will be 952 /// erased. 953 iterator erase(MachineInstr *I) { 954 return erase(iterator(I)); 955 } 956 957 /// Remove the unbundled instruction from the instruction list without 958 /// deleting it. 959 /// 960 /// This function can not be used to remove bundled instructions, use 961 /// remove_instr to remove individual instructions from a bundle. 962 MachineInstr *remove(MachineInstr *I) { 963 assert(!I->isBundled() && "Cannot remove bundled instructions"); 964 return Insts.remove(instr_iterator(I)); 965 } 966 967 /// Remove the possibly bundled instruction from the instruction list 968 /// without deleting it. 969 /// 970 /// If the instruction is part of a bundle, the other instructions in the 971 /// bundle will still be bundled after removing the single instruction. 972 MachineInstr *remove_instr(MachineInstr *I); 973 974 void clear() { 975 Insts.clear(); 976 } 977 978 /// Take an instruction from MBB 'Other' at the position From, and insert it 979 /// into this MBB right before 'Where'. 980 /// 981 /// If From points to a bundle of instructions, the whole bundle is moved. 982 void splice(iterator Where, MachineBasicBlock *Other, iterator From) { 983 // The range splice() doesn't allow noop moves, but this one does. 984 if (Where != From) 985 splice(Where, Other, From, std::next(From)); 986 } 987 988 /// Take a block of instructions from MBB 'Other' in the range [From, To), 989 /// and insert them into this MBB right before 'Where'. 990 /// 991 /// The instruction at 'Where' must not be included in the range of 992 /// instructions to move. 993 void splice(iterator Where, MachineBasicBlock *Other, 994 iterator From, iterator To) { 995 Insts.splice(Where.getInstrIterator(), Other->Insts, 996 From.getInstrIterator(), To.getInstrIterator()); 997 } 998 999 /// This method unlinks 'this' from the containing function, and returns it, 1000 /// but does not delete it. 1001 MachineBasicBlock *removeFromParent(); 1002 1003 /// This method unlinks 'this' from the containing function and deletes it. 1004 void eraseFromParent(); 1005 1006 /// Given a machine basic block that branched to 'Old', change the code and 1007 /// CFG so that it branches to 'New' instead. 1008 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1009 1010 /// Update all phi nodes in this basic block to refer to basic block \p New 1011 /// instead of basic block \p Old. 1012 void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1013 1014 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE 1015 /// and DBG_LABEL instructions. Return UnknownLoc if there is none. 1016 DebugLoc findDebugLoc(instr_iterator MBBI); 1017 DebugLoc findDebugLoc(iterator MBBI) { 1018 return findDebugLoc(MBBI.getInstrIterator()); 1019 } 1020 1021 /// Has exact same behavior as @ref findDebugLoc (it also 1022 /// searches from the first to the last MI of this MBB) except 1023 /// that this takes reverse iterator. 1024 DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI); 1025 DebugLoc rfindDebugLoc(reverse_iterator MBBI) { 1026 return rfindDebugLoc(MBBI.getInstrIterator()); 1027 } 1028 1029 /// Find the previous valid DebugLoc preceding MBBI, skipping and DBG_VALUE 1030 /// instructions. Return UnknownLoc if there is none. 1031 DebugLoc findPrevDebugLoc(instr_iterator MBBI); 1032 DebugLoc findPrevDebugLoc(iterator MBBI) { 1033 return findPrevDebugLoc(MBBI.getInstrIterator()); 1034 } 1035 1036 /// Has exact same behavior as @ref findPrevDebugLoc (it also 1037 /// searches from the last to the first MI of this MBB) except 1038 /// that this takes reverse iterator. 1039 DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI); 1040 DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) { 1041 return rfindPrevDebugLoc(MBBI.getInstrIterator()); 1042 } 1043 1044 /// Find and return the merged DebugLoc of the branch instructions of the 1045 /// block. Return UnknownLoc if there is none. 1046 DebugLoc findBranchDebugLoc(); 1047 1048 /// Possible outcome of a register liveness query to computeRegisterLiveness() 1049 enum LivenessQueryResult { 1050 LQR_Live, ///< Register is known to be (at least partially) live. 1051 LQR_Dead, ///< Register is known to be fully dead. 1052 LQR_Unknown ///< Register liveness not decidable from local neighborhood. 1053 }; 1054 1055 /// Return whether (physical) register \p Reg has been defined and not 1056 /// killed as of just before \p Before. 1057 /// 1058 /// Search is localised to a neighborhood of \p Neighborhood instructions 1059 /// before (searching for defs or kills) and \p Neighborhood instructions 1060 /// after (searching just for defs) \p Before. 1061 /// 1062 /// \p Reg must be a physical register. 1063 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, 1064 MCRegister Reg, 1065 const_iterator Before, 1066 unsigned Neighborhood = 10) const; 1067 1068 // Debugging methods. 1069 void dump() const; 1070 void print(raw_ostream &OS, const SlotIndexes * = nullptr, 1071 bool IsStandalone = true) const; 1072 void print(raw_ostream &OS, ModuleSlotTracker &MST, 1073 const SlotIndexes * = nullptr, bool IsStandalone = true) const; 1074 1075 enum PrintNameFlag { 1076 PrintNameIr = (1 << 0), ///< Add IR name where available 1077 PrintNameAttributes = (1 << 1), ///< Print attributes 1078 }; 1079 1080 void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr, 1081 ModuleSlotTracker *moduleSlotTracker = nullptr) const; 1082 1083 // Printing method used by LoopInfo. 1084 void printAsOperand(raw_ostream &OS, bool PrintType = true) const; 1085 1086 /// MachineBasicBlocks are uniquely numbered at the function level, unless 1087 /// they're not in a MachineFunction yet, in which case this will return -1. 1088 int getNumber() const { return Number; } 1089 void setNumber(int N) { Number = N; } 1090 1091 /// Return the MCSymbol for this basic block. 1092 MCSymbol *getSymbol() const; 1093 1094 /// Return the EHCatchret Symbol for this basic block. 1095 MCSymbol *getEHCatchretSymbol() const; 1096 1097 Optional<uint64_t> getIrrLoopHeaderWeight() const { 1098 return IrrLoopHeaderWeight; 1099 } 1100 1101 void setIrrLoopHeaderWeight(uint64_t Weight) { 1102 IrrLoopHeaderWeight = Weight; 1103 } 1104 1105 /// Return probability of the edge from this block to MBB. This method should 1106 /// NOT be called directly, but by using getEdgeProbability method from 1107 /// MachineBranchProbabilityInfo class. 1108 BranchProbability getSuccProbability(const_succ_iterator Succ) const; 1109 1110 private: 1111 /// Return probability iterator corresponding to the I successor iterator. 1112 probability_iterator getProbabilityIterator(succ_iterator I); 1113 const_probability_iterator 1114 getProbabilityIterator(const_succ_iterator I) const; 1115 1116 friend class MachineBranchProbabilityInfo; 1117 friend class MIPrinter; 1118 1119 // Methods used to maintain doubly linked list of blocks... 1120 friend struct ilist_callback_traits<MachineBasicBlock>; 1121 1122 // Machine-CFG mutators 1123 1124 /// Add Pred as a predecessor of this MachineBasicBlock. Don't do this 1125 /// unless you know what you're doing, because it doesn't update Pred's 1126 /// successors list. Use Pred->addSuccessor instead. 1127 void addPredecessor(MachineBasicBlock *Pred); 1128 1129 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this 1130 /// unless you know what you're doing, because it doesn't update Pred's 1131 /// successors list. Use Pred->removeSuccessor instead. 1132 void removePredecessor(MachineBasicBlock *Pred); 1133 }; 1134 1135 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 1136 1137 /// Prints a machine basic block reference. 1138 /// 1139 /// The format is: 1140 /// %bb.5 - a machine basic block with MBB.getNumber() == 5. 1141 /// 1142 /// Usage: OS << printMBBReference(MBB) << '\n'; 1143 Printable printMBBReference(const MachineBasicBlock &MBB); 1144 1145 // This is useful when building IndexedMaps keyed on basic block pointers. 1146 struct MBB2NumberFunctor { 1147 using argument_type = const MachineBasicBlock *; 1148 unsigned operator()(const MachineBasicBlock *MBB) const { 1149 return MBB->getNumber(); 1150 } 1151 }; 1152 1153 //===--------------------------------------------------------------------===// 1154 // GraphTraits specializations for machine basic block graphs (machine-CFGs) 1155 //===--------------------------------------------------------------------===// 1156 1157 // Provide specializations of GraphTraits to be able to treat a 1158 // MachineFunction as a graph of MachineBasicBlocks. 1159 // 1160 1161 template <> struct GraphTraits<MachineBasicBlock *> { 1162 using NodeRef = MachineBasicBlock *; 1163 using ChildIteratorType = MachineBasicBlock::succ_iterator; 1164 1165 static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } 1166 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1167 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1168 }; 1169 1170 template <> struct GraphTraits<const MachineBasicBlock *> { 1171 using NodeRef = const MachineBasicBlock *; 1172 using ChildIteratorType = MachineBasicBlock::const_succ_iterator; 1173 1174 static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } 1175 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1176 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1177 }; 1178 1179 // Provide specializations of GraphTraits to be able to treat a 1180 // MachineFunction as a graph of MachineBasicBlocks and to walk it 1181 // in inverse order. Inverse order for a function is considered 1182 // to be when traversing the predecessor edges of a MBB 1183 // instead of the successor edges. 1184 // 1185 template <> struct GraphTraits<Inverse<MachineBasicBlock*>> { 1186 using NodeRef = MachineBasicBlock *; 1187 using ChildIteratorType = MachineBasicBlock::pred_iterator; 1188 1189 static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) { 1190 return G.Graph; 1191 } 1192 1193 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1194 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1195 }; 1196 1197 template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> { 1198 using NodeRef = const MachineBasicBlock *; 1199 using ChildIteratorType = MachineBasicBlock::const_pred_iterator; 1200 1201 static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) { 1202 return G.Graph; 1203 } 1204 1205 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1206 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1207 }; 1208 1209 /// MachineInstrSpan provides an interface to get an iteration range 1210 /// containing the instruction it was initialized with, along with all 1211 /// those instructions inserted prior to or following that instruction 1212 /// at some point after the MachineInstrSpan is constructed. 1213 class MachineInstrSpan { 1214 MachineBasicBlock &MBB; 1215 MachineBasicBlock::iterator I, B, E; 1216 1217 public: 1218 MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB) 1219 : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), 1220 E(std::next(I)) { 1221 assert(I == BB->end() || I->getParent() == BB); 1222 } 1223 1224 MachineBasicBlock::iterator begin() { 1225 return B == MBB.end() ? MBB.begin() : std::next(B); 1226 } 1227 MachineBasicBlock::iterator end() { return E; } 1228 bool empty() { return begin() == end(); } 1229 1230 MachineBasicBlock::iterator getInitial() { return I; } 1231 }; 1232 1233 /// Increment \p It until it points to a non-debug instruction or to \p End 1234 /// and return the resulting iterator. This function should only be used 1235 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1236 /// const_instr_iterator} and the respective reverse iterators. 1237 template <typename IterT> 1238 inline IterT skipDebugInstructionsForward(IterT It, IterT End, 1239 bool SkipPseudoOp = true) { 1240 while (It != End && 1241 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1242 ++It; 1243 return It; 1244 } 1245 1246 /// Decrement \p It until it points to a non-debug instruction or to \p Begin 1247 /// and return the resulting iterator. This function should only be used 1248 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1249 /// const_instr_iterator} and the respective reverse iterators. 1250 template <class IterT> 1251 inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin, 1252 bool SkipPseudoOp = true) { 1253 while (It != Begin && 1254 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1255 --It; 1256 return It; 1257 } 1258 1259 /// Increment \p It, then continue incrementing it while it points to a debug 1260 /// instruction. A replacement for std::next. 1261 template <typename IterT> 1262 inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) { 1263 return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp); 1264 } 1265 1266 /// Decrement \p It, then continue decrementing it while it points to a debug 1267 /// instruction. A replacement for std::prev. 1268 template <typename IterT> 1269 inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) { 1270 return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp); 1271 } 1272 1273 /// Construct a range iterator which begins at \p It and moves forwards until 1274 /// \p End is reached, skipping any debug instructions. 1275 template <typename IterT> 1276 inline auto instructionsWithoutDebug(IterT It, IterT End, 1277 bool SkipPseudoOp = true) { 1278 return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) { 1279 return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe()); 1280 }); 1281 } 1282 1283 } // end namespace llvm 1284 1285 #endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H 1286