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 MBBSectionIDMBBSectionID60 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. MBBSectionIDMBBSectionID74 MBBSectionID(SectionType T) : Type(T), Number(0) {} 75 }; 76 77 // This structure represents the information for a basic block pertaining to 78 // the basic block sections profile. 79 struct UniqueBBID { 80 unsigned BaseID; 81 unsigned CloneID; 82 }; 83 84 template <> struct ilist_traits<MachineInstr> { 85 private: 86 friend class MachineBasicBlock; // Set by the owning MachineBasicBlock. 87 88 MachineBasicBlock *Parent; 89 90 using instr_iterator = 91 simple_ilist<MachineInstr, ilist_sentinel_tracking<true>>::iterator; 92 93 public: 94 void addNodeToList(MachineInstr *N); 95 void removeNodeFromList(MachineInstr *N); 96 void transferNodesFromList(ilist_traits &FromList, instr_iterator First, 97 instr_iterator Last); 98 void deleteNode(MachineInstr *MI); 99 }; 100 101 class MachineBasicBlock 102 : public ilist_node_with_parent<MachineBasicBlock, MachineFunction> { 103 public: 104 /// Pair of physical register and lane mask. 105 /// This is not simply a std::pair typedef because the members should be named 106 /// clearly as they both have an integer type. 107 struct RegisterMaskPair { 108 public: 109 MCPhysReg PhysReg; 110 LaneBitmask LaneMask; 111 112 RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask) 113 : PhysReg(PhysReg), LaneMask(LaneMask) {} 114 115 bool operator==(const RegisterMaskPair &other) const { 116 return PhysReg == other.PhysReg && LaneMask == other.LaneMask; 117 } 118 }; 119 120 private: 121 using Instructions = ilist<MachineInstr, ilist_sentinel_tracking<true>>; 122 123 const BasicBlock *BB; 124 int Number; 125 126 /// The call frame size on entry to this basic block due to call frame setup 127 /// instructions in a predecessor. This is usually zero, unless basic blocks 128 /// are split in the middle of a call sequence. 129 /// 130 /// This information is only maintained until PrologEpilogInserter eliminates 131 /// call frame pseudos. 132 unsigned CallFrameSize = 0; 133 134 MachineFunction *xParent; 135 Instructions Insts; 136 137 /// Keep track of the predecessor / successor basic blocks. 138 std::vector<MachineBasicBlock *> Predecessors; 139 std::vector<MachineBasicBlock *> Successors; 140 141 /// Keep track of the probabilities to the successors. This vector has the 142 /// same order as Successors, or it is empty if we don't use it (disable 143 /// optimization). 144 std::vector<BranchProbability> Probs; 145 using probability_iterator = std::vector<BranchProbability>::iterator; 146 using const_probability_iterator = 147 std::vector<BranchProbability>::const_iterator; 148 149 std::optional<uint64_t> IrrLoopHeaderWeight; 150 151 /// Keep track of the physical registers that are livein of the basicblock. 152 using LiveInVector = std::vector<RegisterMaskPair>; 153 LiveInVector LiveIns; 154 155 /// Alignment of the basic block. One if the basic block does not need to be 156 /// aligned. 157 Align Alignment; 158 /// Maximum amount of bytes that can be added to align the basic block. If the 159 /// alignment cannot be reached in this many bytes, no bytes are emitted. 160 /// Zero to represent no maximum. 161 unsigned MaxBytesForAlignment = 0; 162 163 /// Indicate that this basic block is entered via an exception handler. 164 bool IsEHPad = false; 165 166 /// Indicate that this MachineBasicBlock is referenced somewhere other than 167 /// as predecessor/successor, a terminator MachineInstr, or a jump table. 168 bool MachineBlockAddressTaken = false; 169 170 /// If this MachineBasicBlock corresponds to an IR-level "blockaddress" 171 /// constant, this contains a pointer to that block. 172 BasicBlock *AddressTakenIRBlock = nullptr; 173 174 /// Indicate that this basic block needs its symbol be emitted regardless of 175 /// whether the flow just falls-through to it. 176 bool LabelMustBeEmitted = false; 177 178 /// Indicate that this basic block is the entry block of an EH scope, i.e., 179 /// the block that used to have a catchpad or cleanuppad instruction in the 180 /// LLVM IR. 181 bool IsEHScopeEntry = false; 182 183 /// Indicates if this is a target block of a catchret. 184 bool IsEHCatchretTarget = false; 185 186 /// Indicate that this basic block is the entry block of an EH funclet. 187 bool IsEHFuncletEntry = false; 188 189 /// Indicate that this basic block is the entry block of a cleanup funclet. 190 bool IsCleanupFuncletEntry = false; 191 192 /// Fixed unique ID assigned to this basic block upon creation. Used with 193 /// basic block sections and basic block labels. 194 std::optional<UniqueBBID> BBID; 195 196 /// With basic block sections, this stores the Section ID of the basic block. 197 MBBSectionID SectionID{0}; 198 199 // Indicate that this basic block begins a section. 200 bool IsBeginSection = false; 201 202 // Indicate that this basic block ends a section. 203 bool IsEndSection = false; 204 205 /// Indicate that this basic block is the indirect dest of an INLINEASM_BR. 206 bool IsInlineAsmBrIndirectTarget = false; 207 208 /// since getSymbol is a relatively heavy-weight operation, the symbol 209 /// is only computed once and is cached. 210 mutable MCSymbol *CachedMCSymbol = nullptr; 211 212 /// Cached MCSymbol for this block (used if IsEHCatchRetTarget). 213 mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr; 214 215 /// Marks the end of the basic block. Used during basic block sections to 216 /// calculate the size of the basic block, or the BB section ending with it. 217 mutable MCSymbol *CachedEndMCSymbol = nullptr; 218 219 // Intrusive list support 220 MachineBasicBlock() = default; 221 222 explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB); 223 224 ~MachineBasicBlock(); 225 226 // MachineBasicBlocks are allocated and owned by MachineFunction. 227 friend class MachineFunction; 228 229 public: 230 /// Return the LLVM basic block that this instance corresponded to originally. 231 /// Note that this may be NULL if this instance does not correspond directly 232 /// to an LLVM basic block. 233 const BasicBlock *getBasicBlock() const { return BB; } 234 235 /// Remove the reference to the underlying IR BasicBlock. This is for 236 /// reduction tools and should generally not be used. 237 void clearBasicBlock() { 238 BB = nullptr; 239 } 240 241 /// Return the name of the corresponding LLVM basic block, or an empty string. 242 StringRef getName() const; 243 244 /// Return a formatted string to identify this block and its parent function. 245 std::string getFullName() const; 246 247 /// Test whether this block is used as something other than the target 248 /// of a terminator, exception-handling target, or jump table. This is 249 /// either the result of an IR-level "blockaddress", or some form 250 /// of target-specific branch lowering. 251 bool hasAddressTaken() const { 252 return MachineBlockAddressTaken || AddressTakenIRBlock; 253 } 254 255 /// Test whether this block is used as something other than the target of a 256 /// terminator, exception-handling target, jump table, or IR blockaddress. 257 /// For example, its address might be loaded into a register, or 258 /// stored in some branch table that isn't part of MachineJumpTableInfo. 259 bool isMachineBlockAddressTaken() const { return MachineBlockAddressTaken; } 260 261 /// Test whether this block is the target of an IR BlockAddress. (There can 262 /// more than one MBB associated with an IR BB where the address is taken.) 263 bool isIRBlockAddressTaken() const { return AddressTakenIRBlock; } 264 265 /// Retrieves the BasicBlock which corresponds to this MachineBasicBlock. 266 BasicBlock *getAddressTakenIRBlock() const { return AddressTakenIRBlock; } 267 268 /// Set this block to indicate that its address is used as something other 269 /// than the target of a terminator, exception-handling target, jump table, 270 /// or IR-level "blockaddress". 271 void setMachineBlockAddressTaken() { MachineBlockAddressTaken = true; } 272 273 /// Set this block to reflect that it corresponds to an IR-level basic block 274 /// with a BlockAddress. 275 void setAddressTakenIRBlock(BasicBlock *BB) { AddressTakenIRBlock = BB; } 276 277 /// Test whether this block must have its label emitted. 278 bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; } 279 280 /// Set this block to reflect that, regardless how we flow to it, we need 281 /// its label be emitted. 282 void setLabelMustBeEmitted() { LabelMustBeEmitted = true; } 283 284 /// Return the MachineFunction containing this basic block. 285 const MachineFunction *getParent() const { return xParent; } 286 MachineFunction *getParent() { return xParent; } 287 288 using instr_iterator = Instructions::iterator; 289 using const_instr_iterator = Instructions::const_iterator; 290 using reverse_instr_iterator = Instructions::reverse_iterator; 291 using const_reverse_instr_iterator = Instructions::const_reverse_iterator; 292 293 using iterator = MachineInstrBundleIterator<MachineInstr>; 294 using const_iterator = MachineInstrBundleIterator<const MachineInstr>; 295 using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>; 296 using const_reverse_iterator = 297 MachineInstrBundleIterator<const MachineInstr, true>; 298 299 unsigned size() const { return (unsigned)Insts.size(); } 300 bool sizeWithoutDebugLargerThan(unsigned Limit) const; 301 bool empty() const { return Insts.empty(); } 302 303 MachineInstr &instr_front() { return Insts.front(); } 304 MachineInstr &instr_back() { return Insts.back(); } 305 const MachineInstr &instr_front() const { return Insts.front(); } 306 const MachineInstr &instr_back() const { return Insts.back(); } 307 308 MachineInstr &front() { return Insts.front(); } 309 MachineInstr &back() { return *--end(); } 310 const MachineInstr &front() const { return Insts.front(); } 311 const MachineInstr &back() const { return *--end(); } 312 313 instr_iterator instr_begin() { return Insts.begin(); } 314 const_instr_iterator instr_begin() const { return Insts.begin(); } 315 instr_iterator instr_end() { return Insts.end(); } 316 const_instr_iterator instr_end() const { return Insts.end(); } 317 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); } 318 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); } 319 reverse_instr_iterator instr_rend () { return Insts.rend(); } 320 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); } 321 322 using instr_range = iterator_range<instr_iterator>; 323 using const_instr_range = iterator_range<const_instr_iterator>; 324 instr_range instrs() { return instr_range(instr_begin(), instr_end()); } 325 const_instr_range instrs() const { 326 return const_instr_range(instr_begin(), instr_end()); 327 } 328 329 iterator begin() { return instr_begin(); } 330 const_iterator begin() const { return instr_begin(); } 331 iterator end () { return instr_end(); } 332 const_iterator end () const { return instr_end(); } 333 reverse_iterator rbegin() { 334 return reverse_iterator::getAtBundleBegin(instr_rbegin()); 335 } 336 const_reverse_iterator rbegin() const { 337 return const_reverse_iterator::getAtBundleBegin(instr_rbegin()); 338 } 339 reverse_iterator rend() { return reverse_iterator(instr_rend()); } 340 const_reverse_iterator rend() const { 341 return const_reverse_iterator(instr_rend()); 342 } 343 344 /// Support for MachineInstr::getNextNode(). 345 static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) { 346 return &MachineBasicBlock::Insts; 347 } 348 349 inline iterator_range<iterator> terminators() { 350 return make_range(getFirstTerminator(), end()); 351 } 352 inline iterator_range<const_iterator> terminators() const { 353 return make_range(getFirstTerminator(), end()); 354 } 355 356 /// Returns a range that iterates over the phis in the basic block. 357 inline iterator_range<iterator> phis() { 358 return make_range(begin(), getFirstNonPHI()); 359 } 360 inline iterator_range<const_iterator> phis() const { 361 return const_cast<MachineBasicBlock *>(this)->phis(); 362 } 363 364 // Machine-CFG iterators 365 using pred_iterator = std::vector<MachineBasicBlock *>::iterator; 366 using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator; 367 using succ_iterator = std::vector<MachineBasicBlock *>::iterator; 368 using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator; 369 using pred_reverse_iterator = 370 std::vector<MachineBasicBlock *>::reverse_iterator; 371 using const_pred_reverse_iterator = 372 std::vector<MachineBasicBlock *>::const_reverse_iterator; 373 using succ_reverse_iterator = 374 std::vector<MachineBasicBlock *>::reverse_iterator; 375 using const_succ_reverse_iterator = 376 std::vector<MachineBasicBlock *>::const_reverse_iterator; 377 pred_iterator pred_begin() { return Predecessors.begin(); } 378 const_pred_iterator pred_begin() const { return Predecessors.begin(); } 379 pred_iterator pred_end() { return Predecessors.end(); } 380 const_pred_iterator pred_end() const { return Predecessors.end(); } 381 pred_reverse_iterator pred_rbegin() 382 { return Predecessors.rbegin();} 383 const_pred_reverse_iterator pred_rbegin() const 384 { return Predecessors.rbegin();} 385 pred_reverse_iterator pred_rend() 386 { return Predecessors.rend(); } 387 const_pred_reverse_iterator pred_rend() const 388 { return Predecessors.rend(); } 389 unsigned pred_size() const { 390 return (unsigned)Predecessors.size(); 391 } 392 bool pred_empty() const { return Predecessors.empty(); } 393 succ_iterator succ_begin() { return Successors.begin(); } 394 const_succ_iterator succ_begin() const { return Successors.begin(); } 395 succ_iterator succ_end() { return Successors.end(); } 396 const_succ_iterator succ_end() const { return Successors.end(); } 397 succ_reverse_iterator succ_rbegin() 398 { return Successors.rbegin(); } 399 const_succ_reverse_iterator succ_rbegin() const 400 { return Successors.rbegin(); } 401 succ_reverse_iterator succ_rend() 402 { return Successors.rend(); } 403 const_succ_reverse_iterator succ_rend() const 404 { return Successors.rend(); } 405 unsigned succ_size() const { 406 return (unsigned)Successors.size(); 407 } 408 bool succ_empty() const { return Successors.empty(); } 409 410 inline iterator_range<pred_iterator> predecessors() { 411 return make_range(pred_begin(), pred_end()); 412 } 413 inline iterator_range<const_pred_iterator> predecessors() const { 414 return make_range(pred_begin(), pred_end()); 415 } 416 inline iterator_range<succ_iterator> successors() { 417 return make_range(succ_begin(), succ_end()); 418 } 419 inline iterator_range<const_succ_iterator> successors() const { 420 return make_range(succ_begin(), succ_end()); 421 } 422 423 // LiveIn management methods. 424 425 /// Adds the specified register as a live in. Note that it is an error to add 426 /// the same register to the same set more than once unless the intention is 427 /// to call sortUniqueLiveIns after all registers are added. 428 void addLiveIn(MCRegister PhysReg, 429 LaneBitmask LaneMask = LaneBitmask::getAll()) { 430 LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask)); 431 } 432 void addLiveIn(const RegisterMaskPair &RegMaskPair) { 433 LiveIns.push_back(RegMaskPair); 434 } 435 436 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do 437 /// this than repeatedly calling isLiveIn before calling addLiveIn for every 438 /// LiveIn insertion. 439 void sortUniqueLiveIns(); 440 441 /// Clear live in list. 442 void clearLiveIns(); 443 444 /// Add PhysReg as live in to this block, and ensure that there is a copy of 445 /// PhysReg to a virtual register of class RC. Return the virtual register 446 /// that is a copy of the live in PhysReg. 447 Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC); 448 449 /// Remove the specified register from the live in set. 450 void removeLiveIn(MCPhysReg Reg, 451 LaneBitmask LaneMask = LaneBitmask::getAll()); 452 453 /// Return true if the specified register is in the live in set. 454 bool isLiveIn(MCPhysReg Reg, 455 LaneBitmask LaneMask = LaneBitmask::getAll()) const; 456 457 // Iteration support for live in sets. These sets are kept in sorted 458 // order by their register number. 459 using livein_iterator = LiveInVector::const_iterator; 460 461 /// Unlike livein_begin, this method does not check that the liveness 462 /// information is accurate. Still for debug purposes it may be useful 463 /// to have iterators that won't assert if the liveness information 464 /// is not current. 465 livein_iterator livein_begin_dbg() const { return LiveIns.begin(); } 466 iterator_range<livein_iterator> liveins_dbg() const { 467 return make_range(livein_begin_dbg(), livein_end()); 468 } 469 470 livein_iterator livein_begin() const; 471 livein_iterator livein_end() const { return LiveIns.end(); } 472 bool livein_empty() const { return LiveIns.empty(); } 473 iterator_range<livein_iterator> liveins() const { 474 return make_range(livein_begin(), livein_end()); 475 } 476 477 /// Remove entry from the livein set and return iterator to the next. 478 livein_iterator removeLiveIn(livein_iterator I); 479 480 std::vector<RegisterMaskPair> getLiveIns() const { return LiveIns; } 481 482 class liveout_iterator { 483 public: 484 using iterator_category = std::input_iterator_tag; 485 using difference_type = std::ptrdiff_t; 486 using value_type = RegisterMaskPair; 487 using pointer = const RegisterMaskPair *; 488 using reference = const RegisterMaskPair &; 489 490 liveout_iterator(const MachineBasicBlock &MBB, MCPhysReg ExceptionPointer, 491 MCPhysReg ExceptionSelector, bool End) 492 : ExceptionPointer(ExceptionPointer), 493 ExceptionSelector(ExceptionSelector), BlockI(MBB.succ_begin()), 494 BlockEnd(MBB.succ_end()) { 495 if (End) 496 BlockI = BlockEnd; 497 else if (BlockI != BlockEnd) { 498 LiveRegI = (*BlockI)->livein_begin(); 499 if (!advanceToValidPosition()) 500 return; 501 if (LiveRegI->PhysReg == ExceptionPointer || 502 LiveRegI->PhysReg == ExceptionSelector) 503 ++(*this); 504 } 505 } 506 507 liveout_iterator &operator++() { 508 do { 509 ++LiveRegI; 510 if (!advanceToValidPosition()) 511 return *this; 512 } while ((*BlockI)->isEHPad() && 513 (LiveRegI->PhysReg == ExceptionPointer || 514 LiveRegI->PhysReg == ExceptionSelector)); 515 return *this; 516 } 517 518 liveout_iterator operator++(int) { 519 liveout_iterator Tmp = *this; 520 ++(*this); 521 return Tmp; 522 } 523 524 reference operator*() const { 525 return *LiveRegI; 526 } 527 528 pointer operator->() const { 529 return &*LiveRegI; 530 } 531 532 bool operator==(const liveout_iterator &RHS) const { 533 if (BlockI != BlockEnd) 534 return BlockI == RHS.BlockI && LiveRegI == RHS.LiveRegI; 535 return RHS.BlockI == BlockEnd; 536 } 537 538 bool operator!=(const liveout_iterator &RHS) const { 539 return !(*this == RHS); 540 } 541 private: 542 bool advanceToValidPosition() { 543 if (LiveRegI != (*BlockI)->livein_end()) 544 return true; 545 546 do { 547 ++BlockI; 548 } while (BlockI != BlockEnd && (*BlockI)->livein_empty()); 549 if (BlockI == BlockEnd) 550 return false; 551 552 LiveRegI = (*BlockI)->livein_begin(); 553 return true; 554 } 555 556 MCPhysReg ExceptionPointer, ExceptionSelector; 557 const_succ_iterator BlockI; 558 const_succ_iterator BlockEnd; 559 livein_iterator LiveRegI; 560 }; 561 562 /// Iterator scanning successor basic blocks' liveins to determine the 563 /// registers potentially live at the end of this block. There may be 564 /// duplicates or overlapping registers in the list returned. 565 liveout_iterator liveout_begin() const; 566 liveout_iterator liveout_end() const { 567 return liveout_iterator(*this, 0, 0, true); 568 } 569 iterator_range<liveout_iterator> liveouts() const { 570 return make_range(liveout_begin(), liveout_end()); 571 } 572 573 /// Get the clobber mask for the start of this basic block. Funclets use this 574 /// to prevent register allocation across funclet transitions. 575 const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const; 576 577 /// Get the clobber mask for the end of the basic block. 578 /// \see getBeginClobberMask() 579 const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const; 580 581 /// Return alignment of the basic block. 582 Align getAlignment() const { return Alignment; } 583 584 /// Set alignment of the basic block. 585 void setAlignment(Align A) { Alignment = A; } 586 587 void setAlignment(Align A, unsigned MaxBytes) { 588 setAlignment(A); 589 setMaxBytesForAlignment(MaxBytes); 590 } 591 592 /// Return the maximum amount of padding allowed for aligning the basic block. 593 unsigned getMaxBytesForAlignment() const { return MaxBytesForAlignment; } 594 595 /// Set the maximum amount of padding allowed for aligning the basic block 596 void setMaxBytesForAlignment(unsigned MaxBytes) { 597 MaxBytesForAlignment = MaxBytes; 598 } 599 600 /// Returns true if the block is a landing pad. That is this basic block is 601 /// entered via an exception handler. 602 bool isEHPad() const { return IsEHPad; } 603 604 /// Indicates the block is a landing pad. That is this basic block is entered 605 /// via an exception handler. 606 void setIsEHPad(bool V = true) { IsEHPad = V; } 607 608 bool hasEHPadSuccessor() const; 609 610 /// Returns true if this is the entry block of the function. 611 bool isEntryBlock() const; 612 613 /// Returns true if this is the entry block of an EH scope, i.e., the block 614 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 615 bool isEHScopeEntry() const { return IsEHScopeEntry; } 616 617 /// Indicates if this is the entry block of an EH scope, i.e., the block that 618 /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. 619 void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; } 620 621 /// Returns true if this is a target block of a catchret. 622 bool isEHCatchretTarget() const { return IsEHCatchretTarget; } 623 624 /// Indicates if this is a target block of a catchret. 625 void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; } 626 627 /// Returns true if this is the entry block of an EH funclet. 628 bool isEHFuncletEntry() const { return IsEHFuncletEntry; } 629 630 /// Indicates if this is the entry block of an EH funclet. 631 void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; } 632 633 /// Returns true if this is the entry block of a cleanup funclet. 634 bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; } 635 636 /// Indicates if this is the entry block of a cleanup funclet. 637 void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; } 638 639 /// Returns true if this block begins any section. 640 bool isBeginSection() const { return IsBeginSection; } 641 642 /// Returns true if this block ends any section. 643 bool isEndSection() const { return IsEndSection; } 644 645 void setIsBeginSection(bool V = true) { IsBeginSection = V; } 646 647 void setIsEndSection(bool V = true) { IsEndSection = V; } 648 649 std::optional<UniqueBBID> getBBID() const { return BBID; } 650 651 /// Returns the section ID of this basic block. 652 MBBSectionID getSectionID() const { return SectionID; } 653 654 /// Returns the unique section ID number of this basic block. 655 unsigned getSectionIDNum() const { 656 return ((unsigned)MBBSectionID::SectionType::Cold) - 657 ((unsigned)SectionID.Type) + SectionID.Number; 658 } 659 660 /// Sets the fixed BBID of this basic block. 661 void setBBID(const UniqueBBID &V) { 662 assert(!BBID.has_value() && "Cannot change BBID."); 663 BBID = V; 664 } 665 666 /// Sets the section ID for this basic block. 667 void setSectionID(MBBSectionID V) { SectionID = V; } 668 669 /// Returns the MCSymbol marking the end of this basic block. 670 MCSymbol *getEndSymbol() const; 671 672 /// Returns true if this block may have an INLINEASM_BR (overestimate, by 673 /// checking if any of the successors are indirect targets of any inlineasm_br 674 /// in the function). 675 bool mayHaveInlineAsmBr() const; 676 677 /// Returns true if this is the indirect dest of an INLINEASM_BR. 678 bool isInlineAsmBrIndirectTarget() const { 679 return IsInlineAsmBrIndirectTarget; 680 } 681 682 /// Indicates if this is the indirect dest of an INLINEASM_BR. 683 void setIsInlineAsmBrIndirectTarget(bool V = true) { 684 IsInlineAsmBrIndirectTarget = V; 685 } 686 687 /// Returns true if it is legal to hoist instructions into this block. 688 bool isLegalToHoistInto() const; 689 690 // Code Layout methods. 691 692 /// Move 'this' block before or after the specified block. This only moves 693 /// the block, it does not modify the CFG or adjust potential fall-throughs at 694 /// the end of the block. 695 void moveBefore(MachineBasicBlock *NewAfter); 696 void moveAfter(MachineBasicBlock *NewBefore); 697 698 /// Returns true if this and MBB belong to the same section. 699 bool sameSection(const MachineBasicBlock *MBB) const { 700 return getSectionID() == MBB->getSectionID(); 701 } 702 703 /// Update the terminator instructions in block to account for changes to 704 /// block layout which may have been made. PreviousLayoutSuccessor should be 705 /// set to the block which may have been used as fallthrough before the block 706 /// layout was modified. If the block previously fell through to that block, 707 /// it may now need a branch. If it previously branched to another block, it 708 /// may now be able to fallthrough to the current layout successor. 709 void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor); 710 711 // Machine-CFG mutators 712 713 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 714 /// of Succ is automatically updated. PROB parameter is stored in 715 /// Probabilities list. The default probability is set as unknown. Mixing 716 /// known and unknown probabilities in successor list is not allowed. When all 717 /// successors have unknown probabilities, 1 / N is returned as the 718 /// probability for each successor, where N is the number of successors. 719 /// 720 /// Note that duplicate Machine CFG edges are not allowed. 721 void addSuccessor(MachineBasicBlock *Succ, 722 BranchProbability Prob = BranchProbability::getUnknown()); 723 724 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list 725 /// of Succ is automatically updated. The probability is not provided because 726 /// BPI is not available (e.g. -O0 is used), in which case edge probabilities 727 /// won't be used. Using this interface can save some space. 728 void addSuccessorWithoutProb(MachineBasicBlock *Succ); 729 730 /// Set successor probability of a given iterator. 731 void setSuccProbability(succ_iterator I, BranchProbability Prob); 732 733 /// Normalize probabilities of all successors so that the sum of them becomes 734 /// one. This is usually done when the current update on this MBB is done, and 735 /// the sum of its successors' probabilities is not guaranteed to be one. The 736 /// user is responsible for the correct use of this function. 737 /// MBB::removeSuccessor() has an option to do this automatically. 738 void normalizeSuccProbs() { 739 BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end()); 740 } 741 742 /// Validate successors' probabilities and check if the sum of them is 743 /// approximate one. This only works in DEBUG mode. 744 void validateSuccProbs() const; 745 746 /// Remove successor from the successors list of this MachineBasicBlock. The 747 /// Predecessors list of Succ is automatically updated. 748 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 749 /// after the successor is removed. 750 void removeSuccessor(MachineBasicBlock *Succ, 751 bool NormalizeSuccProbs = false); 752 753 /// Remove specified successor from the successors list of this 754 /// MachineBasicBlock. The Predecessors list of Succ is automatically updated. 755 /// If NormalizeSuccProbs is true, then normalize successors' probabilities 756 /// after the successor is removed. 757 /// Return the iterator to the element after the one removed. 758 succ_iterator removeSuccessor(succ_iterator I, 759 bool NormalizeSuccProbs = false); 760 761 /// Replace successor OLD with NEW and update probability info. 762 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New); 763 764 /// Copy a successor (and any probability info) from original block to this 765 /// block's. Uses an iterator into the original blocks successors. 766 /// 767 /// This is useful when doing a partial clone of successors. Afterward, the 768 /// probabilities may need to be normalized. 769 void copySuccessor(const MachineBasicBlock *Orig, succ_iterator I); 770 771 /// Split the old successor into old plus new and updates the probability 772 /// info. 773 void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New, 774 bool NormalizeSuccProbs = false); 775 776 /// Transfers all the successors from MBB to this machine basic block (i.e., 777 /// copies all the successors FromMBB and remove all the successors from 778 /// FromMBB). 779 void transferSuccessors(MachineBasicBlock *FromMBB); 780 781 /// Transfers all the successors, as in transferSuccessors, and update PHI 782 /// operands in the successor blocks which refer to FromMBB to refer to this. 783 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB); 784 785 /// Return true if any of the successors have probabilities attached to them. 786 bool hasSuccessorProbabilities() const { return !Probs.empty(); } 787 788 /// Return true if the specified MBB is a predecessor of this block. 789 bool isPredecessor(const MachineBasicBlock *MBB) const; 790 791 /// Return true if the specified MBB is a successor of this block. 792 bool isSuccessor(const MachineBasicBlock *MBB) const; 793 794 /// Return true if the specified MBB will be emitted immediately after this 795 /// block, such that if this block exits by falling through, control will 796 /// transfer to the specified MBB. Note that MBB need not be a successor at 797 /// all, for example if this block ends with an unconditional branch to some 798 /// other block. 799 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; 800 801 /// Return the successor of this block if it has a single successor. 802 /// Otherwise return a null pointer. 803 /// 804 const MachineBasicBlock *getSingleSuccessor() const; 805 MachineBasicBlock *getSingleSuccessor() { 806 return const_cast<MachineBasicBlock *>( 807 static_cast<const MachineBasicBlock *>(this)->getSingleSuccessor()); 808 } 809 810 /// Return the predecessor of this block if it has a single predecessor. 811 /// Otherwise return a null pointer. 812 /// 813 const MachineBasicBlock *getSinglePredecessor() const; 814 MachineBasicBlock *getSinglePredecessor() { 815 return const_cast<MachineBasicBlock *>( 816 static_cast<const MachineBasicBlock *>(this)->getSinglePredecessor()); 817 } 818 819 /// Return the fallthrough block if the block can implicitly 820 /// transfer control to the block after it by falling off the end of 821 /// it. If an explicit branch to the fallthrough block is not allowed, 822 /// set JumpToFallThrough to be false. Non-null return is a conservative 823 /// answer. 824 MachineBasicBlock *getFallThrough(bool JumpToFallThrough = true); 825 826 /// Return the fallthrough block if the block can implicitly 827 /// transfer control to it's successor, whether by a branch or 828 /// a fallthrough. Non-null return is a conservative answer. 829 MachineBasicBlock *getLogicalFallThrough() { return getFallThrough(false); } 830 831 /// Return true if the block can implicitly transfer control to the 832 /// block after it by falling off the end of it. This should return 833 /// false if it can reach the block after it, but it uses an 834 /// explicit branch to do so (e.g., a table jump). True is a 835 /// conservative answer. 836 bool canFallThrough(); 837 838 /// Returns a pointer to the first instruction in this block that is not a 839 /// PHINode instruction. When adding instructions to the beginning of the 840 /// basic block, they should be added before the returned value, not before 841 /// the first instruction, which might be PHI. 842 /// Returns end() is there's no non-PHI instruction. 843 iterator getFirstNonPHI(); 844 const_iterator getFirstNonPHI() const { 845 return const_cast<MachineBasicBlock *>(this)->getFirstNonPHI(); 846 } 847 848 /// Return the first instruction in MBB after I that is not a PHI or a label. 849 /// This is the correct point to insert lowered copies at the beginning of a 850 /// basic block that must be before any debugging information. 851 iterator SkipPHIsAndLabels(iterator I); 852 853 /// Return the first instruction in MBB after I that is not a PHI, label or 854 /// debug. This is the correct point to insert copies at the beginning of a 855 /// basic block. \p Reg is the register being used by a spill or defined for a 856 /// restore/split during register allocation. 857 iterator SkipPHIsLabelsAndDebug(iterator I, Register Reg = Register(), 858 bool SkipPseudoOp = true); 859 860 /// Returns an iterator to the first terminator instruction of this basic 861 /// block. If a terminator does not exist, it returns end(). 862 iterator getFirstTerminator(); 863 const_iterator getFirstTerminator() const { 864 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator(); 865 } 866 867 /// Same getFirstTerminator but it ignores bundles and return an 868 /// instr_iterator instead. 869 instr_iterator getFirstInstrTerminator(); 870 871 /// Finds the first terminator in a block by scanning forward. This can handle 872 /// cases in GlobalISel where there may be non-terminator instructions between 873 /// terminators, for which getFirstTerminator() will not work correctly. 874 iterator getFirstTerminatorForward(); 875 876 /// Returns an iterator to the first non-debug instruction in the basic block, 877 /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true. 878 /// Pseudo probes are like debug instructions which do not turn into real 879 /// machine code. We try to use the function to skip both debug instructions 880 /// and pseudo probe operations to avoid API proliferation. This should work 881 /// most of the time when considering optimizing the rest of code in the 882 /// block, except for certain cases where pseudo probes are designed to block 883 /// the optimizations. For example, code merge like optimizations are supposed 884 /// to be blocked by pseudo probes for better AutoFDO profile quality. 885 /// Therefore, they should be considered as a valid instruction when this 886 /// function is called in a context of such optimizations. On the other hand, 887 /// \c SkipPseudoOp should be true when it's used in optimizations that 888 /// unlikely hurt profile quality, e.g., without block merging. The default 889 /// value of \c SkipPseudoOp is set to true to maximize code quality in 890 /// general, with an explict false value passed in in a few places like branch 891 /// folding and if-conversion to favor profile quality. 892 iterator getFirstNonDebugInstr(bool SkipPseudoOp = true); 893 const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const { 894 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr( 895 SkipPseudoOp); 896 } 897 898 /// Returns an iterator to the last non-debug instruction in the basic block, 899 /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true. 900 /// Pseudo probes are like debug instructions which do not turn into real 901 /// machine code. We try to use the function to skip both debug instructions 902 /// and pseudo probe operations to avoid API proliferation. This should work 903 /// most of the time when considering optimizing the rest of code in the 904 /// block, except for certain cases where pseudo probes are designed to block 905 /// the optimizations. For example, code merge like optimizations are supposed 906 /// to be blocked by pseudo probes for better AutoFDO profile quality. 907 /// Therefore, they should be considered as a valid instruction when this 908 /// function is called in a context of such optimizations. On the other hand, 909 /// \c SkipPseudoOp should be true when it's used in optimizations that 910 /// unlikely hurt profile quality, e.g., without block merging. The default 911 /// value of \c SkipPseudoOp is set to true to maximize code quality in 912 /// general, with an explict false value passed in in a few places like branch 913 /// folding and if-conversion to favor profile quality. 914 iterator getLastNonDebugInstr(bool SkipPseudoOp = true); 915 const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const { 916 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr( 917 SkipPseudoOp); 918 } 919 920 /// Convenience function that returns true if the block ends in a return 921 /// instruction. 922 bool isReturnBlock() const { 923 return !empty() && back().isReturn(); 924 } 925 926 /// Convenience function that returns true if the bock ends in a EH scope 927 /// return instruction. 928 bool isEHScopeReturnBlock() const { 929 return !empty() && back().isEHScopeReturn(); 930 } 931 932 /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be 933 /// inserted after this block, and all instructions after \p SplitInst moved 934 /// to it (\p SplitInst will be in the original block). If \p LIS is provided, 935 /// LiveIntervals will be appropriately updated. \return the newly inserted 936 /// block. 937 /// 938 /// If \p UpdateLiveIns is true, this will ensure the live ins list is 939 /// accurate, including for physreg uses/defs in the original block. 940 MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true, 941 LiveIntervals *LIS = nullptr); 942 943 /// Split the critical edge from this block to the given successor block, and 944 /// return the newly created block, or null if splitting is not possible. 945 /// 946 /// This function updates LiveVariables, MachineDominatorTree, and 947 /// MachineLoopInfo, as applicable. 948 MachineBasicBlock * 949 SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P, 950 std::vector<SparseBitVector<>> *LiveInSets = nullptr); 951 952 /// Check if the edge between this block and the given successor \p 953 /// Succ, can be split. If this returns true a subsequent call to 954 /// SplitCriticalEdge is guaranteed to return a valid basic block if 955 /// no changes occurred in the meantime. 956 bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; 957 958 void pop_front() { Insts.pop_front(); } 959 void pop_back() { Insts.pop_back(); } 960 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 961 962 /// Insert MI into the instruction list before I, possibly inside a bundle. 963 /// 964 /// If the insertion point is inside a bundle, MI will be added to the bundle, 965 /// otherwise MI will not be added to any bundle. That means this function 966 /// alone can't be used to prepend or append instructions to bundles. See 967 /// MIBundleBuilder::insert() for a more reliable way of doing that. 968 instr_iterator insert(instr_iterator I, MachineInstr *M); 969 970 /// Insert a range of instructions into the instruction list before I. 971 template<typename IT> 972 void insert(iterator I, IT S, IT E) { 973 assert((I == end() || I->getParent() == this) && 974 "iterator points outside of basic block"); 975 Insts.insert(I.getInstrIterator(), S, E); 976 } 977 978 /// Insert MI into the instruction list before I. 979 iterator insert(iterator I, MachineInstr *MI) { 980 assert((I == end() || I->getParent() == this) && 981 "iterator points outside of basic block"); 982 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 983 "Cannot insert instruction with bundle flags"); 984 return Insts.insert(I.getInstrIterator(), MI); 985 } 986 987 /// Insert MI into the instruction list after I. 988 iterator insertAfter(iterator I, MachineInstr *MI) { 989 assert((I == end() || I->getParent() == this) && 990 "iterator points outside of basic block"); 991 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 992 "Cannot insert instruction with bundle flags"); 993 return Insts.insertAfter(I.getInstrIterator(), MI); 994 } 995 996 /// If I is bundled then insert MI into the instruction list after the end of 997 /// the bundle, otherwise insert MI immediately after I. 998 instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) { 999 assert((I == instr_end() || I->getParent() == this) && 1000 "iterator points outside of basic block"); 1001 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 1002 "Cannot insert instruction with bundle flags"); 1003 while (I->isBundledWithSucc()) 1004 ++I; 1005 return Insts.insertAfter(I, MI); 1006 } 1007 1008 /// Remove an instruction from the instruction list and delete it. 1009 /// 1010 /// If the instruction is part of a bundle, the other instructions in the 1011 /// bundle will still be bundled after removing the single instruction. 1012 instr_iterator erase(instr_iterator I); 1013 1014 /// Remove an instruction from the instruction list and delete it. 1015 /// 1016 /// If the instruction is part of a bundle, the other instructions in the 1017 /// bundle will still be bundled after removing the single instruction. 1018 instr_iterator erase_instr(MachineInstr *I) { 1019 return erase(instr_iterator(I)); 1020 } 1021 1022 /// Remove a range of instructions from the instruction list and delete them. 1023 iterator erase(iterator I, iterator E) { 1024 return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); 1025 } 1026 1027 /// Remove an instruction or bundle from the instruction list and delete it. 1028 /// 1029 /// If I points to a bundle of instructions, they are all erased. 1030 iterator erase(iterator I) { 1031 return erase(I, std::next(I)); 1032 } 1033 1034 /// Remove an instruction from the instruction list and delete it. 1035 /// 1036 /// If I is the head of a bundle of instructions, the whole bundle will be 1037 /// erased. 1038 iterator erase(MachineInstr *I) { 1039 return erase(iterator(I)); 1040 } 1041 1042 /// Remove the unbundled instruction from the instruction list without 1043 /// deleting it. 1044 /// 1045 /// This function can not be used to remove bundled instructions, use 1046 /// remove_instr to remove individual instructions from a bundle. 1047 MachineInstr *remove(MachineInstr *I) { 1048 assert(!I->isBundled() && "Cannot remove bundled instructions"); 1049 return Insts.remove(instr_iterator(I)); 1050 } 1051 1052 /// Remove the possibly bundled instruction from the instruction list 1053 /// without deleting it. 1054 /// 1055 /// If the instruction is part of a bundle, the other instructions in the 1056 /// bundle will still be bundled after removing the single instruction. 1057 MachineInstr *remove_instr(MachineInstr *I); 1058 1059 void clear() { 1060 Insts.clear(); 1061 } 1062 1063 /// Take an instruction from MBB 'Other' at the position From, and insert it 1064 /// into this MBB right before 'Where'. 1065 /// 1066 /// If From points to a bundle of instructions, the whole bundle is moved. 1067 void splice(iterator Where, MachineBasicBlock *Other, iterator From) { 1068 // The range splice() doesn't allow noop moves, but this one does. 1069 if (Where != From) 1070 splice(Where, Other, From, std::next(From)); 1071 } 1072 1073 /// Take a block of instructions from MBB 'Other' in the range [From, To), 1074 /// and insert them into this MBB right before 'Where'. 1075 /// 1076 /// The instruction at 'Where' must not be included in the range of 1077 /// instructions to move. 1078 void splice(iterator Where, MachineBasicBlock *Other, 1079 iterator From, iterator To) { 1080 Insts.splice(Where.getInstrIterator(), Other->Insts, 1081 From.getInstrIterator(), To.getInstrIterator()); 1082 } 1083 1084 /// This method unlinks 'this' from the containing function, and returns it, 1085 /// but does not delete it. 1086 MachineBasicBlock *removeFromParent(); 1087 1088 /// This method unlinks 'this' from the containing function and deletes it. 1089 void eraseFromParent(); 1090 1091 /// Given a machine basic block that branched to 'Old', change the code and 1092 /// CFG so that it branches to 'New' instead. 1093 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1094 1095 /// Update all phi nodes in this basic block to refer to basic block \p New 1096 /// instead of basic block \p Old. 1097 void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1098 1099 /// Find the next valid DebugLoc starting at MBBI, skipping any debug 1100 /// instructions. Return UnknownLoc if there is none. 1101 DebugLoc findDebugLoc(instr_iterator MBBI); 1102 DebugLoc findDebugLoc(iterator MBBI) { 1103 return findDebugLoc(MBBI.getInstrIterator()); 1104 } 1105 1106 /// Has exact same behavior as @ref findDebugLoc (it also searches towards the 1107 /// end of this MBB) except that this function takes a reverse iterator to 1108 /// identify the starting MI. 1109 DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI); 1110 DebugLoc rfindDebugLoc(reverse_iterator MBBI) { 1111 return rfindDebugLoc(MBBI.getInstrIterator()); 1112 } 1113 1114 /// Find the previous valid DebugLoc preceding MBBI, skipping any debug 1115 /// instructions. It is possible to find the last DebugLoc in the MBB using 1116 /// findPrevDebugLoc(instr_end()). Return UnknownLoc if there is none. 1117 DebugLoc findPrevDebugLoc(instr_iterator MBBI); 1118 DebugLoc findPrevDebugLoc(iterator MBBI) { 1119 return findPrevDebugLoc(MBBI.getInstrIterator()); 1120 } 1121 1122 /// Has exact same behavior as @ref findPrevDebugLoc (it also searches towards 1123 /// the beginning of this MBB) except that this function takes reverse 1124 /// iterator to identify the starting MI. A minor difference compared to 1125 /// findPrevDebugLoc is that we can't start scanning at "instr_end". 1126 DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI); 1127 DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) { 1128 return rfindPrevDebugLoc(MBBI.getInstrIterator()); 1129 } 1130 1131 /// Find and return the merged DebugLoc of the branch instructions of the 1132 /// block. Return UnknownLoc if there is none. 1133 DebugLoc findBranchDebugLoc(); 1134 1135 /// Possible outcome of a register liveness query to computeRegisterLiveness() 1136 enum LivenessQueryResult { 1137 LQR_Live, ///< Register is known to be (at least partially) live. 1138 LQR_Dead, ///< Register is known to be fully dead. 1139 LQR_Unknown ///< Register liveness not decidable from local neighborhood. 1140 }; 1141 1142 /// Return whether (physical) register \p Reg has been defined and not 1143 /// killed as of just before \p Before. 1144 /// 1145 /// Search is localised to a neighborhood of \p Neighborhood instructions 1146 /// before (searching for defs or kills) and \p Neighborhood instructions 1147 /// after (searching just for defs) \p Before. 1148 /// 1149 /// \p Reg must be a physical register. 1150 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, 1151 MCRegister Reg, 1152 const_iterator Before, 1153 unsigned Neighborhood = 10) const; 1154 1155 // Debugging methods. 1156 void dump() const; 1157 void print(raw_ostream &OS, const SlotIndexes * = nullptr, 1158 bool IsStandalone = true) const; 1159 void print(raw_ostream &OS, ModuleSlotTracker &MST, 1160 const SlotIndexes * = nullptr, bool IsStandalone = true) const; 1161 1162 enum PrintNameFlag { 1163 PrintNameIr = (1 << 0), ///< Add IR name where available 1164 PrintNameAttributes = (1 << 1), ///< Print attributes 1165 }; 1166 1167 void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr, 1168 ModuleSlotTracker *moduleSlotTracker = nullptr) const; 1169 1170 // Printing method used by LoopInfo. 1171 void printAsOperand(raw_ostream &OS, bool PrintType = true) const; 1172 1173 /// MachineBasicBlocks are uniquely numbered at the function level, unless 1174 /// they're not in a MachineFunction yet, in which case this will return -1. 1175 int getNumber() const { return Number; } 1176 void setNumber(int N) { Number = N; } 1177 1178 /// Return the call frame size on entry to this basic block. 1179 unsigned getCallFrameSize() const { return CallFrameSize; } 1180 /// Set the call frame size on entry to this basic block. 1181 void setCallFrameSize(unsigned N) { CallFrameSize = N; } 1182 1183 /// Return the MCSymbol for this basic block. 1184 MCSymbol *getSymbol() const; 1185 1186 /// Return the EHCatchret Symbol for this basic block. 1187 MCSymbol *getEHCatchretSymbol() const; 1188 1189 std::optional<uint64_t> getIrrLoopHeaderWeight() const { 1190 return IrrLoopHeaderWeight; 1191 } 1192 1193 void setIrrLoopHeaderWeight(uint64_t Weight) { 1194 IrrLoopHeaderWeight = Weight; 1195 } 1196 1197 /// Return probability of the edge from this block to MBB. This method should 1198 /// NOT be called directly, but by using getEdgeProbability method from 1199 /// MachineBranchProbabilityInfo class. 1200 BranchProbability getSuccProbability(const_succ_iterator Succ) const; 1201 1202 private: 1203 /// Return probability iterator corresponding to the I successor iterator. 1204 probability_iterator getProbabilityIterator(succ_iterator I); 1205 const_probability_iterator 1206 getProbabilityIterator(const_succ_iterator I) const; 1207 1208 friend class MachineBranchProbabilityInfo; 1209 friend class MIPrinter; 1210 1211 // Methods used to maintain doubly linked list of blocks... 1212 friend struct ilist_callback_traits<MachineBasicBlock>; 1213 1214 // Machine-CFG mutators 1215 1216 /// Add Pred as a predecessor of this MachineBasicBlock. Don't do this 1217 /// unless you know what you're doing, because it doesn't update Pred's 1218 /// successors list. Use Pred->addSuccessor instead. 1219 void addPredecessor(MachineBasicBlock *Pred); 1220 1221 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this 1222 /// unless you know what you're doing, because it doesn't update Pred's 1223 /// successors list. Use Pred->removeSuccessor instead. 1224 void removePredecessor(MachineBasicBlock *Pred); 1225 }; 1226 1227 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 1228 1229 /// Prints a machine basic block reference. 1230 /// 1231 /// The format is: 1232 /// %bb.5 - a machine basic block with MBB.getNumber() == 5. 1233 /// 1234 /// Usage: OS << printMBBReference(MBB) << '\n'; 1235 Printable printMBBReference(const MachineBasicBlock &MBB); 1236 1237 // This is useful when building IndexedMaps keyed on basic block pointers. 1238 struct MBB2NumberFunctor { 1239 using argument_type = const MachineBasicBlock *; 1240 unsigned operator()(const MachineBasicBlock *MBB) const { 1241 return MBB->getNumber(); 1242 } 1243 }; 1244 1245 //===--------------------------------------------------------------------===// 1246 // GraphTraits specializations for machine basic block graphs (machine-CFGs) 1247 //===--------------------------------------------------------------------===// 1248 1249 // Provide specializations of GraphTraits to be able to treat a 1250 // MachineFunction as a graph of MachineBasicBlocks. 1251 // 1252 1253 template <> struct GraphTraits<MachineBasicBlock *> { 1254 using NodeRef = MachineBasicBlock *; 1255 using ChildIteratorType = MachineBasicBlock::succ_iterator; 1256 1257 static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } 1258 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1259 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1260 }; 1261 1262 template <> struct GraphTraits<const MachineBasicBlock *> { 1263 using NodeRef = const MachineBasicBlock *; 1264 using ChildIteratorType = MachineBasicBlock::const_succ_iterator; 1265 1266 static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } 1267 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1268 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1269 }; 1270 1271 // Provide specializations of GraphTraits to be able to treat a 1272 // MachineFunction as a graph of MachineBasicBlocks and to walk it 1273 // in inverse order. Inverse order for a function is considered 1274 // to be when traversing the predecessor edges of a MBB 1275 // instead of the successor edges. 1276 // 1277 template <> struct GraphTraits<Inverse<MachineBasicBlock*>> { 1278 using NodeRef = MachineBasicBlock *; 1279 using ChildIteratorType = MachineBasicBlock::pred_iterator; 1280 1281 static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) { 1282 return G.Graph; 1283 } 1284 1285 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1286 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1287 }; 1288 1289 template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> { 1290 using NodeRef = const MachineBasicBlock *; 1291 using ChildIteratorType = MachineBasicBlock::const_pred_iterator; 1292 1293 static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) { 1294 return G.Graph; 1295 } 1296 1297 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1298 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1299 }; 1300 1301 // These accessors are handy for sharing templated code between IR and MIR. 1302 inline auto successors(const MachineBasicBlock *BB) { return BB->successors(); } 1303 inline auto predecessors(const MachineBasicBlock *BB) { 1304 return BB->predecessors(); 1305 } 1306 1307 /// MachineInstrSpan provides an interface to get an iteration range 1308 /// containing the instruction it was initialized with, along with all 1309 /// those instructions inserted prior to or following that instruction 1310 /// at some point after the MachineInstrSpan is constructed. 1311 class MachineInstrSpan { 1312 MachineBasicBlock &MBB; 1313 MachineBasicBlock::iterator I, B, E; 1314 1315 public: 1316 MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB) 1317 : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), 1318 E(std::next(I)) { 1319 assert(I == BB->end() || I->getParent() == BB); 1320 } 1321 1322 MachineBasicBlock::iterator begin() { 1323 return B == MBB.end() ? MBB.begin() : std::next(B); 1324 } 1325 MachineBasicBlock::iterator end() { return E; } 1326 bool empty() { return begin() == end(); } 1327 1328 MachineBasicBlock::iterator getInitial() { return I; } 1329 }; 1330 1331 /// Increment \p It until it points to a non-debug instruction or to \p End 1332 /// and return the resulting iterator. This function should only be used 1333 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1334 /// const_instr_iterator} and the respective reverse iterators. 1335 template <typename IterT> 1336 inline IterT skipDebugInstructionsForward(IterT It, IterT End, 1337 bool SkipPseudoOp = true) { 1338 while (It != End && 1339 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1340 ++It; 1341 return It; 1342 } 1343 1344 /// Decrement \p It until it points to a non-debug instruction or to \p Begin 1345 /// and return the resulting iterator. This function should only be used 1346 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1347 /// const_instr_iterator} and the respective reverse iterators. 1348 template <class IterT> 1349 inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin, 1350 bool SkipPseudoOp = true) { 1351 while (It != Begin && 1352 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1353 --It; 1354 return It; 1355 } 1356 1357 /// Increment \p It, then continue incrementing it while it points to a debug 1358 /// instruction. A replacement for std::next. 1359 template <typename IterT> 1360 inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) { 1361 return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp); 1362 } 1363 1364 /// Decrement \p It, then continue decrementing it while it points to a debug 1365 /// instruction. A replacement for std::prev. 1366 template <typename IterT> 1367 inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) { 1368 return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp); 1369 } 1370 1371 /// Construct a range iterator which begins at \p It and moves forwards until 1372 /// \p End is reached, skipping any debug instructions. 1373 template <typename IterT> 1374 inline auto instructionsWithoutDebug(IterT It, IterT End, 1375 bool SkipPseudoOp = true) { 1376 return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) { 1377 return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe()); 1378 }); 1379 } 1380 1381 } // end namespace llvm 1382 1383 #endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H 1384