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 std::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 MachineBasicBlock is referenced somewhere other than 147 /// as predecessor/successor, a terminator MachineInstr, or a jump table. 148 bool MachineBlockAddressTaken = false; 149 150 /// If this MachineBasicBlock corresponds to an IR-level "blockaddress" 151 /// constant, this contains a pointer to that block. 152 BasicBlock *AddressTakenIRBlock = nullptr; 153 154 /// Indicate that this basic block needs its symbol be emitted regardless of 155 /// whether the flow just falls-through to it. 156 bool LabelMustBeEmitted = false; 157 158 /// Indicate that this basic block is the entry block of an EH scope, i.e., 159 /// the block that used to have a catchpad or cleanuppad instruction in the 160 /// LLVM IR. 161 bool IsEHScopeEntry = false; 162 163 /// Indicates if this is a target block of a catchret. 164 bool IsEHCatchretTarget = false; 165 166 /// Indicate that this basic block is the entry block of an EH funclet. 167 bool IsEHFuncletEntry = false; 168 169 /// Indicate that this basic block is the entry block of a cleanup funclet. 170 bool IsCleanupFuncletEntry = false; 171 172 /// Fixed unique ID assigned to this basic block upon creation. Used with 173 /// basic block sections and basic block labels. 174 std::optional<unsigned> BBID; 175 176 /// With basic block sections, this stores the Section ID of the basic block. 177 MBBSectionID SectionID{0}; 178 179 // Indicate that this basic block begins a section. 180 bool IsBeginSection = false; 181 182 // Indicate that this basic block ends a section. 183 bool IsEndSection = false; 184 185 /// Indicate that this basic block is the indirect dest of an INLINEASM_BR. 186 bool IsInlineAsmBrIndirectTarget = false; 187 188 /// since getSymbol is a relatively heavy-weight operation, the symbol 189 /// is only computed once and is cached. 190 mutable MCSymbol *CachedMCSymbol = nullptr; 191 192 /// Cached MCSymbol for this block (used if IsEHCatchRetTarget). 193 mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr; 194 195 /// Marks the end of the basic block. Used during basic block sections to 196 /// calculate the size of the basic block, or the BB section ending with it. 197 mutable MCSymbol *CachedEndMCSymbol = nullptr; 198 199 // Intrusive list support 200 MachineBasicBlock() = default; 201 202 explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB); 203 204 ~MachineBasicBlock(); 205 206 // MachineBasicBlocks are allocated and owned by MachineFunction. 207 friend class MachineFunction; 208 209 public: 210 /// Return the LLVM basic block that this instance corresponded to originally. 211 /// Note that this may be NULL if this instance does not correspond directly 212 /// to an LLVM basic block. 213 const BasicBlock *getBasicBlock() const { return BB; } 214 215 /// Remove the reference to the underlying IR BasicBlock. This is for 216 /// reduction tools and should generally not be used. 217 void clearBasicBlock() { 218 BB = nullptr; 219 } 220 221 /// Return the name of the corresponding LLVM basic block, or an empty string. 222 StringRef getName() const; 223 224 /// Return a formatted string to identify this block and its parent function. 225 std::string getFullName() const; 226 227 /// Test whether this block is used as as something other than the target 228 /// of a terminator, exception-handling target, or jump table. This is 229 /// either the result of an IR-level "blockaddress", or some form 230 /// of target-specific branch lowering. 231 bool hasAddressTaken() const { 232 return MachineBlockAddressTaken || AddressTakenIRBlock; 233 } 234 235 /// Test whether this block is used as something other than the target of a 236 /// terminator, exception-handling target, jump table, or IR blockaddress. 237 /// For example, its address might be loaded into a register, or 238 /// stored in some branch table that isn't part of MachineJumpTableInfo. 239 bool isMachineBlockAddressTaken() const { return MachineBlockAddressTaken; } 240 241 /// Test whether this block is the target of an IR BlockAddress. (There can 242 /// more than one MBB associated with an IR BB where the address is taken.) 243 bool isIRBlockAddressTaken() const { return AddressTakenIRBlock; } 244 245 /// Retrieves the BasicBlock which corresponds to this MachineBasicBlock. 246 BasicBlock *getAddressTakenIRBlock() const { return AddressTakenIRBlock; } 247 248 /// Set this block to indicate that its address is used as something other 249 /// than the target of a terminator, exception-handling target, jump table, 250 /// or IR-level "blockaddress". 251 void setMachineBlockAddressTaken() { MachineBlockAddressTaken = true; } 252 253 /// Set this block to reflect that it corresponds to an IR-level basic block 254 /// with a BlockAddress. 255 void setAddressTakenIRBlock(BasicBlock *BB) { AddressTakenIRBlock = BB; } 256 257 /// Test whether this block must have its label emitted. 258 bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; } 259 260 /// Set this block to reflect that, regardless how we flow to it, we need 261 /// its label be emitted. 262 void setLabelMustBeEmitted() { LabelMustBeEmitted = true; } 263 264 /// Return the MachineFunction containing this basic block. 265 const MachineFunction *getParent() const { return xParent; } 266 MachineFunction *getParent() { return xParent; } 267 268 using instr_iterator = Instructions::iterator; 269 using const_instr_iterator = Instructions::const_iterator; 270 using reverse_instr_iterator = Instructions::reverse_iterator; 271 using const_reverse_instr_iterator = Instructions::const_reverse_iterator; 272 273 using iterator = MachineInstrBundleIterator<MachineInstr>; 274 using const_iterator = MachineInstrBundleIterator<const MachineInstr>; 275 using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>; 276 using const_reverse_iterator = 277 MachineInstrBundleIterator<const MachineInstr, true>; 278 279 unsigned size() const { return (unsigned)Insts.size(); } 280 bool sizeWithoutDebugLargerThan(unsigned Limit) const; 281 bool empty() const { return Insts.empty(); } 282 283 MachineInstr &instr_front() { return Insts.front(); } 284 MachineInstr &instr_back() { return Insts.back(); } 285 const MachineInstr &instr_front() const { return Insts.front(); } 286 const MachineInstr &instr_back() const { return Insts.back(); } 287 288 MachineInstr &front() { return Insts.front(); } 289 MachineInstr &back() { return *--end(); } 290 const MachineInstr &front() const { return Insts.front(); } 291 const MachineInstr &back() const { return *--end(); } 292 293 instr_iterator instr_begin() { return Insts.begin(); } 294 const_instr_iterator instr_begin() const { return Insts.begin(); } 295 instr_iterator instr_end() { return Insts.end(); } 296 const_instr_iterator instr_end() const { return Insts.end(); } 297 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); } 298 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); } 299 reverse_instr_iterator instr_rend () { return Insts.rend(); } 300 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); } 301 302 using instr_range = iterator_range<instr_iterator>; 303 using const_instr_range = iterator_range<const_instr_iterator>; 304 instr_range instrs() { return instr_range(instr_begin(), instr_end()); } 305 const_instr_range instrs() const { 306 return const_instr_range(instr_begin(), instr_end()); 307 } 308 309 iterator begin() { return instr_begin(); } 310 const_iterator begin() const { return instr_begin(); } 311 iterator end () { return instr_end(); } 312 const_iterator end () const { return instr_end(); } 313 reverse_iterator rbegin() { 314 return reverse_iterator::getAtBundleBegin(instr_rbegin()); 315 } 316 const_reverse_iterator rbegin() const { 317 return const_reverse_iterator::getAtBundleBegin(instr_rbegin()); 318 } 319 reverse_iterator rend() { return reverse_iterator(instr_rend()); } 320 const_reverse_iterator rend() const { 321 return const_reverse_iterator(instr_rend()); 322 } 323 324 /// Support for MachineInstr::getNextNode(). 325 static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) { 326 return &MachineBasicBlock::Insts; 327 } 328 329 inline iterator_range<iterator> terminators() { 330 return make_range(getFirstTerminator(), end()); 331 } 332 inline iterator_range<const_iterator> terminators() const { 333 return make_range(getFirstTerminator(), end()); 334 } 335 336 /// Returns a range that iterates over the phis in the basic block. 337 inline iterator_range<iterator> phis() { 338 return make_range(begin(), getFirstNonPHI()); 339 } 340 inline iterator_range<const_iterator> phis() const { 341 return const_cast<MachineBasicBlock *>(this)->phis(); 342 } 343 344 // Machine-CFG iterators 345 using pred_iterator = std::vector<MachineBasicBlock *>::iterator; 346 using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator; 347 using succ_iterator = std::vector<MachineBasicBlock *>::iterator; 348 using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator; 349 using pred_reverse_iterator = 350 std::vector<MachineBasicBlock *>::reverse_iterator; 351 using const_pred_reverse_iterator = 352 std::vector<MachineBasicBlock *>::const_reverse_iterator; 353 using succ_reverse_iterator = 354 std::vector<MachineBasicBlock *>::reverse_iterator; 355 using const_succ_reverse_iterator = 356 std::vector<MachineBasicBlock *>::const_reverse_iterator; 357 pred_iterator pred_begin() { return Predecessors.begin(); } 358 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 359 pred_iterator pred_end() { return Predecessors.end(); } 360 const_pred_iterator pred_end() const { return Predecessors.end(); } 361 pred_reverse_iterator pred_rbegin() 362 { return Predecessors.rbegin();} 363 const_pred_reverse_iterator pred_rbegin() const 364 { return Predecessors.rbegin();} 365 pred_reverse_iterator pred_rend() 366 { return Predecessors.rend(); } 367 const_pred_reverse_iterator pred_rend() const 368 { return Predecessors.rend(); } 369 unsigned pred_size() const { 370 return (unsigned)Predecessors.size(); 371 } 372 bool pred_empty() const { return Predecessors.empty(); } 373 succ_iterator succ_begin() { return Successors.begin(); } 374 const_succ_iterator succ_begin() const { return Successors.begin(); } 375 succ_iterator succ_end() { return Successors.end(); } 376 const_succ_iterator succ_end() const { return Successors.end(); } 377 succ_reverse_iterator succ_rbegin() 378 { return Successors.rbegin(); } 379 const_succ_reverse_iterator succ_rbegin() const 380 { return Successors.rbegin(); } 381 succ_reverse_iterator succ_rend() 382 { return Successors.rend(); } 383 const_succ_reverse_iterator succ_rend() const 384 { return Successors.rend(); } 385 unsigned succ_size() const { 386 return (unsigned)Successors.size(); 387 } 388 bool succ_empty() const { return Successors.empty(); } 389 390 inline iterator_range<pred_iterator> predecessors() { 391 return make_range(pred_begin(), pred_end()); 392 } 393 inline iterator_range<const_pred_iterator> predecessors() const { 394 return make_range(pred_begin(), pred_end()); 395 } 396 inline iterator_range<succ_iterator> successors() { 397 return make_range(succ_begin(), succ_end()); 398 } 399 inline iterator_range<const_succ_iterator> successors() const { 400 return make_range(succ_begin(), succ_end()); 401 } 402 403 // LiveIn management methods. 404 405 /// Adds the specified register as a live in. Note that it is an error to add 406 /// the same register to the same set more than once unless the intention is 407 /// to call sortUniqueLiveIns after all registers are added. 408 void addLiveIn(MCRegister PhysReg, 409 LaneBitmask LaneMask = LaneBitmask::getAll()) { 410 LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask)); 411 } 412 void addLiveIn(const RegisterMaskPair &RegMaskPair) { 413 LiveIns.push_back(RegMaskPair); 414 } 415 416 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do 417 /// this than repeatedly calling isLiveIn before calling addLiveIn for every 418 /// LiveIn insertion. 419 void sortUniqueLiveIns(); 420 421 /// Clear live in list. 422 void clearLiveIns(); 423 424 /// Add PhysReg as live in to this block, and ensure that there is a copy of 425 /// PhysReg to a virtual register of class RC. Return the virtual register 426 /// that is a copy of the live in PhysReg. 427 Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC); 428 429 /// Remove the specified register from the live in set. 430 void removeLiveIn(MCPhysReg Reg, 431 LaneBitmask LaneMask = LaneBitmask::getAll()); 432 433 /// Return true if the specified register is in the live in set. 434 bool isLiveIn(MCPhysReg Reg, 435 LaneBitmask LaneMask = LaneBitmask::getAll()) const; 436 437 // Iteration support for live in sets. These sets are kept in sorted 438 // order by their register number. 439 using livein_iterator = LiveInVector::const_iterator; 440 441 /// Unlike livein_begin, this method does not check that the liveness 442 /// information is accurate. Still for debug purposes it may be useful 443 /// to have iterators that won't assert if the liveness information 444 /// is not current. 445 livein_iterator livein_begin_dbg() const { return LiveIns.begin(); } 446 iterator_range<livein_iterator> liveins_dbg() const { 447 return make_range(livein_begin_dbg(), livein_end()); 448 } 449 450 livein_iterator livein_begin() const; 451 livein_iterator livein_end() const { return LiveIns.end(); } 452 bool livein_empty() const { return LiveIns.empty(); } 453 iterator_range<livein_iterator> liveins() const { 454 return make_range(livein_begin(), livein_end()); 455 } 456 457 /// Remove entry from the livein set and return iterator to the next. 458 livein_iterator removeLiveIn(livein_iterator I); 459 460 class liveout_iterator { 461 public: 462 using iterator_category = std::input_iterator_tag; 463 using difference_type = std::ptrdiff_t; 464 using value_type = RegisterMaskPair; 465 using pointer = const RegisterMaskPair *; 466 using reference = const RegisterMaskPair &; 467 468 liveout_iterator(const MachineBasicBlock &MBB, MCPhysReg ExceptionPointer, 469 MCPhysReg ExceptionSelector, bool End) 470 : ExceptionPointer(ExceptionPointer), 471 ExceptionSelector(ExceptionSelector), BlockI(MBB.succ_begin()), 472 BlockEnd(MBB.succ_end()) { 473 if (End) 474 BlockI = BlockEnd; 475 else if (BlockI != BlockEnd) { 476 LiveRegI = (*BlockI)->livein_begin(); 477 if (!advanceToValidPosition()) 478 return; 479 if (LiveRegI->PhysReg == ExceptionPointer || 480 LiveRegI->PhysReg == ExceptionSelector) 481 ++(*this); 482 } 483 } 484 485 liveout_iterator &operator++() { 486 do { 487 ++LiveRegI; 488 if (!advanceToValidPosition()) 489 return *this; 490 } while ((*BlockI)->isEHPad() && 491 (LiveRegI->PhysReg == ExceptionPointer || 492 LiveRegI->PhysReg == ExceptionSelector)); 493 return *this; 494 } 495 496 liveout_iterator operator++(int) { 497 liveout_iterator Tmp = *this; 498 ++(*this); 499 return Tmp; 500 } 501 502 reference operator*() const { 503 return *LiveRegI; 504 } 505 506 pointer operator->() const { 507 return &*LiveRegI; 508 } 509 510 bool operator==(const liveout_iterator &RHS) const { 511 if (BlockI != BlockEnd) 512 return BlockI == RHS.BlockI && LiveRegI == RHS.LiveRegI; 513 return RHS.BlockI == BlockEnd; 514 } 515 516 bool operator!=(const liveout_iterator &RHS) const { 517 return !(*this == RHS); 518 } 519 private: 520 bool advanceToValidPosition() { 521 if (LiveRegI != (*BlockI)->livein_end()) 522 return true; 523 524 do { 525 ++BlockI; 526 } while (BlockI != BlockEnd && (*BlockI)->livein_empty()); 527 if (BlockI == BlockEnd) 528 return false; 529 530 LiveRegI = (*BlockI)->livein_begin(); 531 return true; 532 } 533 534 MCPhysReg ExceptionPointer, ExceptionSelector; 535 const_succ_iterator BlockI; 536 const_succ_iterator BlockEnd; 537 livein_iterator LiveRegI; 538 }; 539 540 /// Iterator scanning successor basic blocks' liveins to determine the 541 /// registers potentially live at the end of this block. There may be 542 /// duplicates or overlapping registers in the list returned. 543 liveout_iterator liveout_begin() const; 544 liveout_iterator liveout_end() const { 545 return liveout_iterator(*this, 0, 0, true); 546 } 547 iterator_range<liveout_iterator> liveouts() const { 548 return make_range(liveout_begin(), liveout_end()); 549 } 550 551 /// Get the clobber mask for the start of this basic block. Funclets use this 552 /// to prevent register allocation across funclet transitions. 553 const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const; 554 555 /// Get the clobber mask for the end of the basic block. 556 /// \see getBeginClobberMask() 557 const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const; 558 559 /// Return alignment of the basic block. 560 Align getAlignment() const { return Alignment; } 561 562 /// Set alignment of the basic block. 563 void setAlignment(Align A) { Alignment = A; } 564 565 void setAlignment(Align A, unsigned MaxBytes) { 566 setAlignment(A); 567 setMaxBytesForAlignment(MaxBytes); 568 } 569 570 /// Return the maximum amount of padding allowed for aligning the basic block. 571 unsigned getMaxBytesForAlignment() const { return MaxBytesForAlignment; } 572 573 /// Set the maximum amount of padding allowed for aligning the basic block 574 void setMaxBytesForAlignment(unsigned MaxBytes) { 575 MaxBytesForAlignment = MaxBytes; 576 } 577 578 /// Returns true if the block is a landing pad. That is this basic block is 579 /// entered via an exception handler. 580 bool isEHPad() const { return IsEHPad; } 581 582 /// Indicates the block is a landing pad. That is this basic block is entered 583 /// via an exception handler. 584 void setIsEHPad(bool V = true) { IsEHPad = V; } 585 586 bool hasEHPadSuccessor() const; 587 588 /// Returns true if this is the entry block of the function. 589 bool isEntryBlock() const; 590 591 /// Returns true if this is the entry block of an EH scope, i.e., the block 592 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 593 bool isEHScopeEntry() const { return IsEHScopeEntry; } 594 595 /// Indicates if this is the entry block of an EH scope, i.e., the block that 596 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 597 void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; } 598 599 /// Returns true if this is a target block of a catchret. 600 bool isEHCatchretTarget() const { return IsEHCatchretTarget; } 601 602 /// Indicates if this is a target block of a catchret. 603 void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; } 604 605 /// Returns true if this is the entry block of an EH funclet. 606 bool isEHFuncletEntry() const { return IsEHFuncletEntry; } 607 608 /// Indicates if this is the entry block of an EH funclet. 609 void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; } 610 611 /// Returns true if this is the entry block of a cleanup funclet. 612 bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; } 613 614 /// Indicates if this is the entry block of a cleanup funclet. 615 void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; } 616 617 /// Returns true if this block begins any section. 618 bool isBeginSection() const { return IsBeginSection; } 619 620 /// Returns true if this block ends any section. 621 bool isEndSection() const { return IsEndSection; } 622 623 void setIsBeginSection(bool V = true) { IsBeginSection = V; } 624 625 void setIsEndSection(bool V = true) { IsEndSection = V; } 626 627 std::optional<unsigned> getBBID() const { return BBID; } 628 629 /// Returns the BBID of the block when BBAddrMapVersion >= 2, otherwise 630 /// returns `MachineBasicBlock::Number`. 631 /// TODO: Remove this function when version 1 is deprecated and replace its 632 /// uses with `getBBID()`. 633 unsigned getBBIDOrNumber() const; 634 635 /// Returns the section ID of this basic block. 636 MBBSectionID getSectionID() const { return SectionID; } 637 638 /// Returns the unique section ID number of this basic block. 639 unsigned getSectionIDNum() const { 640 return ((unsigned)MBBSectionID::SectionType::Cold) - 641 ((unsigned)SectionID.Type) + SectionID.Number; 642 } 643 644 /// Sets the fixed BBID of this basic block. 645 void setBBID(unsigned V) { 646 assert(!BBID.has_value() && "Cannot change BBID."); 647 BBID = V; 648 } 649 650 /// Sets the section ID for this basic block. 651 void setSectionID(MBBSectionID V) { SectionID = V; } 652 653 /// Returns the MCSymbol marking the end of this basic block. 654 MCSymbol *getEndSymbol() const; 655 656 /// Returns true if this block may have an INLINEASM_BR (overestimate, by 657 /// checking if any of the successors are indirect targets of any inlineasm_br 658 /// in the function). 659 bool mayHaveInlineAsmBr() const; 660 661 /// Returns true if this is the indirect dest of an INLINEASM_BR. 662 bool isInlineAsmBrIndirectTarget() const { 663 return IsInlineAsmBrIndirectTarget; 664 } 665 666 /// Indicates if this is the indirect dest of an INLINEASM_BR. 667 void setIsInlineAsmBrIndirectTarget(bool V = true) { 668 IsInlineAsmBrIndirectTarget = V; 669 } 670 671 /// Returns true if it is legal to hoist instructions into this block. 672 bool isLegalToHoistInto() const; 673 674 // Code Layout methods. 675 676 /// Move 'this' block before or after the specified block. This only moves 677 /// the block, it does not modify the CFG or adjust potential fall-throughs at 678 /// the end of the block. 679 void moveBefore(MachineBasicBlock *NewAfter); 680 void moveAfter(MachineBasicBlock *NewBefore); 681 682 /// Returns true if this and MBB belong to the same section. 683 bool sameSection(const MachineBasicBlock *MBB) const { 684 return getSectionID() == MBB->getSectionID(); 685 } 686 687 /// Update the terminator instructions in block to account for changes to 688 /// block layout which may have been made. PreviousLayoutSuccessor should be 689 /// set to the block which may have been used as fallthrough before the block 690 /// layout was modified. If the block previously fell through to that block, 691 /// it may now need a branch. If it previously branched to another block, it 692 /// may now be able to fallthrough to the current layout successor. 693 void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor); 694 695 // Machine-CFG mutators 696 697 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 698 /// of Succ is automatically updated. PROB parameter is stored in 699 /// Probabilities list. The default probability is set as unknown. Mixing 700 /// known and unknown probabilities in successor list is not allowed. When all 701 /// successors have unknown probabilities, 1 / N is returned as the 702 /// probability for each successor, where N is the number of successors. 703 /// 704 /// Note that duplicate Machine CFG edges are not allowed. 705 void addSuccessor(MachineBasicBlock *Succ, 706 BranchProbability Prob = BranchProbability::getUnknown()); 707 708 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 709 /// of Succ is automatically updated. The probability is not provided because 710 /// BPI is not available (e.g. -O0 is used), in which case edge probabilities 711 /// won't be used. Using this interface can save some space. 712 void addSuccessorWithoutProb(MachineBasicBlock *Succ); 713 714 /// Set successor probability of a given iterator. 715 void setSuccProbability(succ_iterator I, BranchProbability Prob); 716 717 /// Normalize probabilities of all successors so that the sum of them becomes 718 /// one. This is usually done when the current update on this MBB is done, and 719 /// the sum of its successors' probabilities is not guaranteed to be one. The 720 /// user is responsible for the correct use of this function. 721 /// MBB::removeSuccessor() has an option to do this automatically. 722 void normalizeSuccProbs() { 723 BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end()); 724 } 725 726 /// Validate successors' probabilities and check if the sum of them is 727 /// approximate one. This only works in DEBUG mode. 728 void validateSuccProbs() const; 729 730 /// Remove successor from the successors list of this MachineBasicBlock. The 731 /// Predecessors list of Succ is automatically updated. 732 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 733 /// after the successor is removed. 734 void removeSuccessor(MachineBasicBlock *Succ, 735 bool NormalizeSuccProbs = false); 736 737 /// Remove specified successor from the successors list of this 738 /// MachineBasicBlock. The Predecessors list of Succ is automatically updated. 739 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 740 /// after the successor is removed. 741 /// Return the iterator to the element after the one removed. 742 succ_iterator removeSuccessor(succ_iterator I, 743 bool NormalizeSuccProbs = false); 744 745 /// Replace successor OLD with NEW and update probability info. 746 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New); 747 748 /// Copy a successor (and any probability info) from original block to this 749 /// block's. Uses an iterator into the original blocks successors. 750 /// 751 /// This is useful when doing a partial clone of successors. Afterward, the 752 /// probabilities may need to be normalized. 753 void copySuccessor(MachineBasicBlock *Orig, succ_iterator I); 754 755 /// Split the old successor into old plus new and updates the probability 756 /// info. 757 void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New, 758 bool NormalizeSuccProbs = false); 759 760 /// Transfers all the successors from MBB to this machine basic block (i.e., 761 /// copies all the successors FromMBB and remove all the successors from 762 /// FromMBB). 763 void transferSuccessors(MachineBasicBlock *FromMBB); 764 765 /// Transfers all the successors, as in transferSuccessors, and update PHI 766 /// operands in the successor blocks which refer to FromMBB to refer to this. 767 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB); 768 769 /// Return true if any of the successors have probabilities attached to them. 770 bool hasSuccessorProbabilities() const { return !Probs.empty(); } 771 772 /// Return true if the specified MBB is a predecessor of this block. 773 bool isPredecessor(const MachineBasicBlock *MBB) const; 774 775 /// Return true if the specified MBB is a successor of this block. 776 bool isSuccessor(const MachineBasicBlock *MBB) const; 777 778 /// Return true if the specified MBB will be emitted immediately after this 779 /// block, such that if this block exits by falling through, control will 780 /// transfer to the specified MBB. Note that MBB need not be a successor at 781 /// all, for example if this block ends with an unconditional branch to some 782 /// other block. 783 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; 784 785 /// Return the successor of this block if it has a single successor. 786 /// Otherwise return a null pointer. 787 /// 788 const MachineBasicBlock *getSingleSuccessor() const; 789 MachineBasicBlock *getSingleSuccessor() { 790 return const_cast<MachineBasicBlock *>( 791 static_cast<const MachineBasicBlock *>(this)->getSingleSuccessor()); 792 } 793 794 /// Return the fallthrough block if the block can implicitly 795 /// transfer control to the block after it by falling off the end of 796 /// it. If an explicit branch to the fallthrough block is not allowed, 797 /// set JumpToFallThrough to be false. Non-null return is a conservative 798 /// answer. 799 MachineBasicBlock *getFallThrough(bool JumpToFallThrough = false); 800 801 /// Return the fallthrough block if the block can implicitly 802 /// transfer control to it's successor, whether by a branch or 803 /// a fallthrough. Non-null return is a conservative answer. 804 MachineBasicBlock *getLogicalFallThrough() { return getFallThrough(true); } 805 806 /// Return true if the block can implicitly transfer control to the 807 /// block after it by falling off the end of it. This should return 808 /// false if it can reach the block after it, but it uses an 809 /// explicit branch to do so (e.g., a table jump). True is a 810 /// conservative answer. 811 bool canFallThrough(); 812 813 /// Returns a pointer to the first instruction in this block that is not a 814 /// PHINode instruction. When adding instructions to the beginning of the 815 /// basic block, they should be added before the returned value, not before 816 /// the first instruction, which might be PHI. 817 /// Returns end() is there's no non-PHI instruction. 818 iterator getFirstNonPHI(); 819 820 /// Return the first instruction in MBB after I that is not a PHI or a label. 821 /// This is the correct point to insert lowered copies at the beginning of a 822 /// basic block that must be before any debugging information. 823 iterator SkipPHIsAndLabels(iterator I); 824 825 /// Return the first instruction in MBB after I that is not a PHI, label or 826 /// debug. This is the correct point to insert copies at the beginning of a 827 /// basic block. 828 iterator SkipPHIsLabelsAndDebug(iterator I, bool SkipPseudoOp = true); 829 830 /// Returns an iterator to the first terminator instruction of this basic 831 /// block. If a terminator does not exist, it returns end(). 832 iterator getFirstTerminator(); 833 const_iterator getFirstTerminator() const { 834 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator(); 835 } 836 837 /// Same getFirstTerminator but it ignores bundles and return an 838 /// instr_iterator instead. 839 instr_iterator getFirstInstrTerminator(); 840 841 /// Finds the first terminator in a block by scanning forward. This can handle 842 /// cases in GlobalISel where there may be non-terminator instructions between 843 /// terminators, for which getFirstTerminator() will not work correctly. 844 iterator getFirstTerminatorForward(); 845 846 /// Returns an iterator to the first non-debug instruction in the basic block, 847 /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true. 848 /// Pseudo probes are like debug instructions which do not turn into real 849 /// machine code. We try to use the function to skip both debug instructions 850 /// and pseudo probe operations to avoid API proliferation. This should work 851 /// most of the time when considering optimizing the rest of code in the 852 /// block, except for certain cases where pseudo probes are designed to block 853 /// the optimizations. For example, code merge like optimizations are supposed 854 /// to be blocked by pseudo probes for better AutoFDO profile quality. 855 /// Therefore, they should be considered as a valid instruction when this 856 /// function is called in a context of such optimizations. On the other hand, 857 /// \c SkipPseudoOp should be true when it's used in optimizations that 858 /// unlikely hurt profile quality, e.g., without block merging. The default 859 /// value of \c SkipPseudoOp is set to true to maximize code quality in 860 /// general, with an explict false value passed in in a few places like branch 861 /// folding and if-conversion to favor profile quality. 862 iterator getFirstNonDebugInstr(bool SkipPseudoOp = true); 863 const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const { 864 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr( 865 SkipPseudoOp); 866 } 867 868 /// Returns an iterator to the last non-debug instruction in the basic block, 869 /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true. 870 /// Pseudo probes are like debug instructions which do not turn into real 871 /// machine code. We try to use the function to skip both debug instructions 872 /// and pseudo probe operations to avoid API proliferation. This should work 873 /// most of the time when considering optimizing the rest of code in the 874 /// block, except for certain cases where pseudo probes are designed to block 875 /// the optimizations. For example, code merge like optimizations are supposed 876 /// to be blocked by pseudo probes for better AutoFDO profile quality. 877 /// Therefore, they should be considered as a valid instruction when this 878 /// function is called in a context of such optimizations. On the other hand, 879 /// \c SkipPseudoOp should be true when it's used in optimizations that 880 /// unlikely hurt profile quality, e.g., without block merging. The default 881 /// value of \c SkipPseudoOp is set to true to maximize code quality in 882 /// general, with an explict false value passed in in a few places like branch 883 /// folding and if-conversion to favor profile quality. 884 iterator getLastNonDebugInstr(bool SkipPseudoOp = true); 885 const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const { 886 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr( 887 SkipPseudoOp); 888 } 889 890 /// Convenience function that returns true if the block ends in a return 891 /// instruction. 892 bool isReturnBlock() const { 893 return !empty() && back().isReturn(); 894 } 895 896 /// Convenience function that returns true if the bock ends in a EH scope 897 /// return instruction. 898 bool isEHScopeReturnBlock() const { 899 return !empty() && back().isEHScopeReturn(); 900 } 901 902 /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be 903 /// inserted after this block, and all instructions after \p SplitInst moved 904 /// to it (\p SplitInst will be in the original block). If \p LIS is provided, 905 /// LiveIntervals will be appropriately updated. \return the newly inserted 906 /// block. 907 /// 908 /// If \p UpdateLiveIns is true, this will ensure the live ins list is 909 /// accurate, including for physreg uses/defs in the original block. 910 MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true, 911 LiveIntervals *LIS = nullptr); 912 913 /// Split the critical edge from this block to the given successor block, and 914 /// return the newly created block, or null if splitting is not possible. 915 /// 916 /// This function updates LiveVariables, MachineDominatorTree, and 917 /// MachineLoopInfo, as applicable. 918 MachineBasicBlock * 919 SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P, 920 std::vector<SparseBitVector<>> *LiveInSets = nullptr); 921 922 /// Check if the edge between this block and the given successor \p 923 /// Succ, can be split. If this returns true a subsequent call to 924 /// SplitCriticalEdge is guaranteed to return a valid basic block if 925 /// no changes occurred in the meantime. 926 bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; 927 928 void pop_front() { Insts.pop_front(); } 929 void pop_back() { Insts.pop_back(); } 930 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 931 932 /// Insert MI into the instruction list before I, possibly inside a bundle. 933 /// 934 /// If the insertion point is inside a bundle, MI will be added to the bundle, 935 /// otherwise MI will not be added to any bundle. That means this function 936 /// alone can't be used to prepend or append instructions to bundles. See 937 /// MIBundleBuilder::insert() for a more reliable way of doing that. 938 instr_iterator insert(instr_iterator I, MachineInstr *M); 939 940 /// Insert a range of instructions into the instruction list before I. 941 template<typename IT> 942 void insert(iterator I, IT S, IT E) { 943 assert((I == end() || I->getParent() == this) && 944 "iterator points outside of basic block"); 945 Insts.insert(I.getInstrIterator(), S, E); 946 } 947 948 /// Insert MI into the instruction list before I. 949 iterator insert(iterator I, MachineInstr *MI) { 950 assert((I == end() || I->getParent() == this) && 951 "iterator points outside of basic block"); 952 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 953 "Cannot insert instruction with bundle flags"); 954 return Insts.insert(I.getInstrIterator(), MI); 955 } 956 957 /// Insert MI into the instruction list after I. 958 iterator insertAfter(iterator I, MachineInstr *MI) { 959 assert((I == end() || I->getParent() == this) && 960 "iterator points outside of basic block"); 961 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 962 "Cannot insert instruction with bundle flags"); 963 return Insts.insertAfter(I.getInstrIterator(), MI); 964 } 965 966 /// If I is bundled then insert MI into the instruction list after the end of 967 /// the bundle, otherwise insert MI immediately after I. 968 instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) { 969 assert((I == instr_end() || I->getParent() == this) && 970 "iterator points outside of basic block"); 971 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 972 "Cannot insert instruction with bundle flags"); 973 while (I->isBundledWithSucc()) 974 ++I; 975 return Insts.insertAfter(I, MI); 976 } 977 978 /// Remove an instruction from the instruction list and delete it. 979 /// 980 /// If the instruction is part of a bundle, the other instructions in the 981 /// bundle will still be bundled after removing the single instruction. 982 instr_iterator erase(instr_iterator I); 983 984 /// Remove an instruction from the instruction list and delete it. 985 /// 986 /// If the instruction is part of a bundle, the other instructions in the 987 /// bundle will still be bundled after removing the single instruction. 988 instr_iterator erase_instr(MachineInstr *I) { 989 return erase(instr_iterator(I)); 990 } 991 992 /// Remove a range of instructions from the instruction list and delete them. 993 iterator erase(iterator I, iterator E) { 994 return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); 995 } 996 997 /// Remove an instruction or bundle from the instruction list and delete it. 998 /// 999 /// If I points to a bundle of instructions, they are all erased. 1000 iterator erase(iterator I) { 1001 return erase(I, std::next(I)); 1002 } 1003 1004 /// Remove an instruction from the instruction list and delete it. 1005 /// 1006 /// If I is the head of a bundle of instructions, the whole bundle will be 1007 /// erased. 1008 iterator erase(MachineInstr *I) { 1009 return erase(iterator(I)); 1010 } 1011 1012 /// Remove the unbundled instruction from the instruction list without 1013 /// deleting it. 1014 /// 1015 /// This function can not be used to remove bundled instructions, use 1016 /// remove_instr to remove individual instructions from a bundle. 1017 MachineInstr *remove(MachineInstr *I) { 1018 assert(!I->isBundled() && "Cannot remove bundled instructions"); 1019 return Insts.remove(instr_iterator(I)); 1020 } 1021 1022 /// Remove the possibly bundled instruction from the instruction list 1023 /// without deleting it. 1024 /// 1025 /// If the instruction is part of a bundle, the other instructions in the 1026 /// bundle will still be bundled after removing the single instruction. 1027 MachineInstr *remove_instr(MachineInstr *I); 1028 1029 void clear() { 1030 Insts.clear(); 1031 } 1032 1033 /// Take an instruction from MBB 'Other' at the position From, and insert it 1034 /// into this MBB right before 'Where'. 1035 /// 1036 /// If From points to a bundle of instructions, the whole bundle is moved. 1037 void splice(iterator Where, MachineBasicBlock *Other, iterator From) { 1038 // The range splice() doesn't allow noop moves, but this one does. 1039 if (Where != From) 1040 splice(Where, Other, From, std::next(From)); 1041 } 1042 1043 /// Take a block of instructions from MBB 'Other' in the range [From, To), 1044 /// and insert them into this MBB right before 'Where'. 1045 /// 1046 /// The instruction at 'Where' must not be included in the range of 1047 /// instructions to move. 1048 void splice(iterator Where, MachineBasicBlock *Other, 1049 iterator From, iterator To) { 1050 Insts.splice(Where.getInstrIterator(), Other->Insts, 1051 From.getInstrIterator(), To.getInstrIterator()); 1052 } 1053 1054 /// This method unlinks 'this' from the containing function, and returns it, 1055 /// but does not delete it. 1056 MachineBasicBlock *removeFromParent(); 1057 1058 /// This method unlinks 'this' from the containing function and deletes it. 1059 void eraseFromParent(); 1060 1061 /// Given a machine basic block that branched to 'Old', change the code and 1062 /// CFG so that it branches to 'New' instead. 1063 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1064 1065 /// Update all phi nodes in this basic block to refer to basic block \p New 1066 /// instead of basic block \p Old. 1067 void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1068 1069 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE 1070 /// and DBG_LABEL instructions. Return UnknownLoc if there is none. 1071 DebugLoc findDebugLoc(instr_iterator MBBI); 1072 DebugLoc findDebugLoc(iterator MBBI) { 1073 return findDebugLoc(MBBI.getInstrIterator()); 1074 } 1075 1076 /// Has exact same behavior as @ref findDebugLoc (it also 1077 /// searches from the first to the last MI of this MBB) except 1078 /// that this takes reverse iterator. 1079 DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI); 1080 DebugLoc rfindDebugLoc(reverse_iterator MBBI) { 1081 return rfindDebugLoc(MBBI.getInstrIterator()); 1082 } 1083 1084 /// Find the previous valid DebugLoc preceding MBBI, skipping and DBG_VALUE 1085 /// instructions. Return UnknownLoc if there is none. 1086 DebugLoc findPrevDebugLoc(instr_iterator MBBI); 1087 DebugLoc findPrevDebugLoc(iterator MBBI) { 1088 return findPrevDebugLoc(MBBI.getInstrIterator()); 1089 } 1090 1091 /// Has exact same behavior as @ref findPrevDebugLoc (it also 1092 /// searches from the last to the first MI of this MBB) except 1093 /// that this takes reverse iterator. 1094 DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI); 1095 DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) { 1096 return rfindPrevDebugLoc(MBBI.getInstrIterator()); 1097 } 1098 1099 /// Find and return the merged DebugLoc of the branch instructions of the 1100 /// block. Return UnknownLoc if there is none. 1101 DebugLoc findBranchDebugLoc(); 1102 1103 /// Possible outcome of a register liveness query to computeRegisterLiveness() 1104 enum LivenessQueryResult { 1105 LQR_Live, ///< Register is known to be (at least partially) live. 1106 LQR_Dead, ///< Register is known to be fully dead. 1107 LQR_Unknown ///< Register liveness not decidable from local neighborhood. 1108 }; 1109 1110 /// Return whether (physical) register \p Reg has been defined and not 1111 /// killed as of just before \p Before. 1112 /// 1113 /// Search is localised to a neighborhood of \p Neighborhood instructions 1114 /// before (searching for defs or kills) and \p Neighborhood instructions 1115 /// after (searching just for defs) \p Before. 1116 /// 1117 /// \p Reg must be a physical register. 1118 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, 1119 MCRegister Reg, 1120 const_iterator Before, 1121 unsigned Neighborhood = 10) const; 1122 1123 // Debugging methods. 1124 void dump() const; 1125 void print(raw_ostream &OS, const SlotIndexes * = nullptr, 1126 bool IsStandalone = true) const; 1127 void print(raw_ostream &OS, ModuleSlotTracker &MST, 1128 const SlotIndexes * = nullptr, bool IsStandalone = true) const; 1129 1130 enum PrintNameFlag { 1131 PrintNameIr = (1 << 0), ///< Add IR name where available 1132 PrintNameAttributes = (1 << 1), ///< Print attributes 1133 }; 1134 1135 void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr, 1136 ModuleSlotTracker *moduleSlotTracker = nullptr) const; 1137 1138 // Printing method used by LoopInfo. 1139 void printAsOperand(raw_ostream &OS, bool PrintType = true) const; 1140 1141 /// MachineBasicBlocks are uniquely numbered at the function level, unless 1142 /// they're not in a MachineFunction yet, in which case this will return -1. 1143 int getNumber() const { return Number; } 1144 void setNumber(int N) { Number = N; } 1145 1146 /// Return the MCSymbol for this basic block. 1147 MCSymbol *getSymbol() const; 1148 1149 /// Return the EHCatchret Symbol for this basic block. 1150 MCSymbol *getEHCatchretSymbol() const; 1151 1152 std::optional<uint64_t> getIrrLoopHeaderWeight() const { 1153 return IrrLoopHeaderWeight; 1154 } 1155 1156 void setIrrLoopHeaderWeight(uint64_t Weight) { 1157 IrrLoopHeaderWeight = Weight; 1158 } 1159 1160 /// Return probability of the edge from this block to MBB. This method should 1161 /// NOT be called directly, but by using getEdgeProbability method from 1162 /// MachineBranchProbabilityInfo class. 1163 BranchProbability getSuccProbability(const_succ_iterator Succ) const; 1164 1165 private: 1166 /// Return probability iterator corresponding to the I successor iterator. 1167 probability_iterator getProbabilityIterator(succ_iterator I); 1168 const_probability_iterator 1169 getProbabilityIterator(const_succ_iterator I) const; 1170 1171 friend class MachineBranchProbabilityInfo; 1172 friend class MIPrinter; 1173 1174 // Methods used to maintain doubly linked list of blocks... 1175 friend struct ilist_callback_traits<MachineBasicBlock>; 1176 1177 // Machine-CFG mutators 1178 1179 /// Add Pred as a predecessor of this MachineBasicBlock. Don't do this 1180 /// unless you know what you're doing, because it doesn't update Pred's 1181 /// successors list. Use Pred->addSuccessor instead. 1182 void addPredecessor(MachineBasicBlock *Pred); 1183 1184 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this 1185 /// unless you know what you're doing, because it doesn't update Pred's 1186 /// successors list. Use Pred->removeSuccessor instead. 1187 void removePredecessor(MachineBasicBlock *Pred); 1188 }; 1189 1190 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 1191 1192 /// Prints a machine basic block reference. 1193 /// 1194 /// The format is: 1195 /// %bb.5 - a machine basic block with MBB.getNumber() == 5. 1196 /// 1197 /// Usage: OS << printMBBReference(MBB) << '\n'; 1198 Printable printMBBReference(const MachineBasicBlock &MBB); 1199 1200 // This is useful when building IndexedMaps keyed on basic block pointers. 1201 struct MBB2NumberFunctor { 1202 using argument_type = const MachineBasicBlock *; 1203 unsigned operator()(const MachineBasicBlock *MBB) const { 1204 return MBB->getNumber(); 1205 } 1206 }; 1207 1208 //===--------------------------------------------------------------------===// 1209 // GraphTraits specializations for machine basic block graphs (machine-CFGs) 1210 //===--------------------------------------------------------------------===// 1211 1212 // Provide specializations of GraphTraits to be able to treat a 1213 // MachineFunction as a graph of MachineBasicBlocks. 1214 // 1215 1216 template <> struct GraphTraits<MachineBasicBlock *> { 1217 using NodeRef = MachineBasicBlock *; 1218 using ChildIteratorType = MachineBasicBlock::succ_iterator; 1219 1220 static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } 1221 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1222 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1223 }; 1224 1225 template <> struct GraphTraits<const MachineBasicBlock *> { 1226 using NodeRef = const MachineBasicBlock *; 1227 using ChildIteratorType = MachineBasicBlock::const_succ_iterator; 1228 1229 static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } 1230 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1231 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1232 }; 1233 1234 // Provide specializations of GraphTraits to be able to treat a 1235 // MachineFunction as a graph of MachineBasicBlocks and to walk it 1236 // in inverse order. Inverse order for a function is considered 1237 // to be when traversing the predecessor edges of a MBB 1238 // instead of the successor edges. 1239 // 1240 template <> struct GraphTraits<Inverse<MachineBasicBlock*>> { 1241 using NodeRef = MachineBasicBlock *; 1242 using ChildIteratorType = MachineBasicBlock::pred_iterator; 1243 1244 static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) { 1245 return G.Graph; 1246 } 1247 1248 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1249 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1250 }; 1251 1252 template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> { 1253 using NodeRef = const MachineBasicBlock *; 1254 using ChildIteratorType = MachineBasicBlock::const_pred_iterator; 1255 1256 static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) { 1257 return G.Graph; 1258 } 1259 1260 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1261 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1262 }; 1263 1264 /// MachineInstrSpan provides an interface to get an iteration range 1265 /// containing the instruction it was initialized with, along with all 1266 /// those instructions inserted prior to or following that instruction 1267 /// at some point after the MachineInstrSpan is constructed. 1268 class MachineInstrSpan { 1269 MachineBasicBlock &MBB; 1270 MachineBasicBlock::iterator I, B, E; 1271 1272 public: 1273 MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB) 1274 : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), 1275 E(std::next(I)) { 1276 assert(I == BB->end() || I->getParent() == BB); 1277 } 1278 1279 MachineBasicBlock::iterator begin() { 1280 return B == MBB.end() ? MBB.begin() : std::next(B); 1281 } 1282 MachineBasicBlock::iterator end() { return E; } 1283 bool empty() { return begin() == end(); } 1284 1285 MachineBasicBlock::iterator getInitial() { return I; } 1286 }; 1287 1288 /// Increment \p It until it points to a non-debug instruction or to \p End 1289 /// and return the resulting iterator. This function should only be used 1290 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1291 /// const_instr_iterator} and the respective reverse iterators. 1292 template <typename IterT> 1293 inline IterT skipDebugInstructionsForward(IterT It, IterT End, 1294 bool SkipPseudoOp = true) { 1295 while (It != End && 1296 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1297 ++It; 1298 return It; 1299 } 1300 1301 /// Decrement \p It until it points to a non-debug instruction or to \p Begin 1302 /// and return the resulting iterator. This function should only be used 1303 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1304 /// const_instr_iterator} and the respective reverse iterators. 1305 template <class IterT> 1306 inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin, 1307 bool SkipPseudoOp = true) { 1308 while (It != Begin && 1309 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1310 --It; 1311 return It; 1312 } 1313 1314 /// Increment \p It, then continue incrementing it while it points to a debug 1315 /// instruction. A replacement for std::next. 1316 template <typename IterT> 1317 inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) { 1318 return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp); 1319 } 1320 1321 /// Decrement \p It, then continue decrementing it while it points to a debug 1322 /// instruction. A replacement for std::prev. 1323 template <typename IterT> 1324 inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) { 1325 return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp); 1326 } 1327 1328 /// Construct a range iterator which begins at \p It and moves forwards until 1329 /// \p End is reached, skipping any debug instructions. 1330 template <typename IterT> 1331 inline auto instructionsWithoutDebug(IterT It, IterT End, 1332 bool SkipPseudoOp = true) { 1333 return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) { 1334 return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe()); 1335 }); 1336 } 1337 1338 } // end namespace llvm 1339 1340 #endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H 1341