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 = true); 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(false); } 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 const_iterator getFirstNonPHI() const { 820 return const_cast<MachineBasicBlock *>(this)->getFirstNonPHI(); 821 } 822 823 /// Return the first instruction in MBB after I that is not a PHI or a label. 824 /// This is the correct point to insert lowered copies at the beginning of a 825 /// basic block that must be before any debugging information. 826 iterator SkipPHIsAndLabels(iterator I); 827 828 /// Return the first instruction in MBB after I that is not a PHI, label or 829 /// debug. This is the correct point to insert copies at the beginning of a 830 /// basic block. 831 iterator SkipPHIsLabelsAndDebug(iterator I, bool SkipPseudoOp = true); 832 833 /// Returns an iterator to the first terminator instruction of this basic 834 /// block. If a terminator does not exist, it returns end(). 835 iterator getFirstTerminator(); 836 const_iterator getFirstTerminator() const { 837 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator(); 838 } 839 840 /// Same getFirstTerminator but it ignores bundles and return an 841 /// instr_iterator instead. 842 instr_iterator getFirstInstrTerminator(); 843 844 /// Finds the first terminator in a block by scanning forward. This can handle 845 /// cases in GlobalISel where there may be non-terminator instructions between 846 /// terminators, for which getFirstTerminator() will not work correctly. 847 iterator getFirstTerminatorForward(); 848 849 /// Returns an iterator to the first non-debug instruction in the basic block, 850 /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true. 851 /// Pseudo probes are like debug instructions which do not turn into real 852 /// machine code. We try to use the function to skip both debug instructions 853 /// and pseudo probe operations to avoid API proliferation. This should work 854 /// most of the time when considering optimizing the rest of code in the 855 /// block, except for certain cases where pseudo probes are designed to block 856 /// the optimizations. For example, code merge like optimizations are supposed 857 /// to be blocked by pseudo probes for better AutoFDO profile quality. 858 /// Therefore, they should be considered as a valid instruction when this 859 /// function is called in a context of such optimizations. On the other hand, 860 /// \c SkipPseudoOp should be true when it's used in optimizations that 861 /// unlikely hurt profile quality, e.g., without block merging. The default 862 /// value of \c SkipPseudoOp is set to true to maximize code quality in 863 /// general, with an explict false value passed in in a few places like branch 864 /// folding and if-conversion to favor profile quality. 865 iterator getFirstNonDebugInstr(bool SkipPseudoOp = true); 866 const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const { 867 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr( 868 SkipPseudoOp); 869 } 870 871 /// Returns an iterator to the last non-debug instruction in the basic block, 872 /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true. 873 /// Pseudo probes are like debug instructions which do not turn into real 874 /// machine code. We try to use the function to skip both debug instructions 875 /// and pseudo probe operations to avoid API proliferation. This should work 876 /// most of the time when considering optimizing the rest of code in the 877 /// block, except for certain cases where pseudo probes are designed to block 878 /// the optimizations. For example, code merge like optimizations are supposed 879 /// to be blocked by pseudo probes for better AutoFDO profile quality. 880 /// Therefore, they should be considered as a valid instruction when this 881 /// function is called in a context of such optimizations. On the other hand, 882 /// \c SkipPseudoOp should be true when it's used in optimizations that 883 /// unlikely hurt profile quality, e.g., without block merging. The default 884 /// value of \c SkipPseudoOp is set to true to maximize code quality in 885 /// general, with an explict false value passed in in a few places like branch 886 /// folding and if-conversion to favor profile quality. 887 iterator getLastNonDebugInstr(bool SkipPseudoOp = true); 888 const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const { 889 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr( 890 SkipPseudoOp); 891 } 892 893 /// Convenience function that returns true if the block ends in a return 894 /// instruction. 895 bool isReturnBlock() const { 896 return !empty() && back().isReturn(); 897 } 898 899 /// Convenience function that returns true if the bock ends in a EH scope 900 /// return instruction. 901 bool isEHScopeReturnBlock() const { 902 return !empty() && back().isEHScopeReturn(); 903 } 904 905 /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be 906 /// inserted after this block, and all instructions after \p SplitInst moved 907 /// to it (\p SplitInst will be in the original block). If \p LIS is provided, 908 /// LiveIntervals will be appropriately updated. \return the newly inserted 909 /// block. 910 /// 911 /// If \p UpdateLiveIns is true, this will ensure the live ins list is 912 /// accurate, including for physreg uses/defs in the original block. 913 MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true, 914 LiveIntervals *LIS = nullptr); 915 916 /// Split the critical edge from this block to the given successor block, and 917 /// return the newly created block, or null if splitting is not possible. 918 /// 919 /// This function updates LiveVariables, MachineDominatorTree, and 920 /// MachineLoopInfo, as applicable. 921 MachineBasicBlock * 922 SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P, 923 std::vector<SparseBitVector<>> *LiveInSets = nullptr); 924 925 /// Check if the edge between this block and the given successor \p 926 /// Succ, can be split. If this returns true a subsequent call to 927 /// SplitCriticalEdge is guaranteed to return a valid basic block if 928 /// no changes occurred in the meantime. 929 bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; 930 931 void pop_front() { Insts.pop_front(); } 932 void pop_back() { Insts.pop_back(); } 933 void push_back(MachineInstr *MI) { Insts.push_back(MI); } 934 935 /// Insert MI into the instruction list before I, possibly inside a bundle. 936 /// 937 /// If the insertion point is inside a bundle, MI will be added to the bundle, 938 /// otherwise MI will not be added to any bundle. That means this function 939 /// alone can't be used to prepend or append instructions to bundles. See 940 /// MIBundleBuilder::insert() for a more reliable way of doing that. 941 instr_iterator insert(instr_iterator I, MachineInstr *M); 942 943 /// Insert a range of instructions into the instruction list before I. 944 template<typename IT> 945 void insert(iterator I, IT S, IT E) { 946 assert((I == end() || I->getParent() == this) && 947 "iterator points outside of basic block"); 948 Insts.insert(I.getInstrIterator(), S, E); 949 } 950 951 /// Insert MI into the instruction list before I. 952 iterator insert(iterator I, MachineInstr *MI) { 953 assert((I == end() || I->getParent() == this) && 954 "iterator points outside of basic block"); 955 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 956 "Cannot insert instruction with bundle flags"); 957 return Insts.insert(I.getInstrIterator(), MI); 958 } 959 960 /// Insert MI into the instruction list after I. 961 iterator insertAfter(iterator I, MachineInstr *MI) { 962 assert((I == end() || I->getParent() == this) && 963 "iterator points outside of basic block"); 964 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 965 "Cannot insert instruction with bundle flags"); 966 return Insts.insertAfter(I.getInstrIterator(), MI); 967 } 968 969 /// If I is bundled then insert MI into the instruction list after the end of 970 /// the bundle, otherwise insert MI immediately after I. 971 instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) { 972 assert((I == instr_end() || I->getParent() == this) && 973 "iterator points outside of basic block"); 974 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && 975 "Cannot insert instruction with bundle flags"); 976 while (I->isBundledWithSucc()) 977 ++I; 978 return Insts.insertAfter(I, MI); 979 } 980 981 /// Remove an instruction from the instruction list and delete it. 982 /// 983 /// If the instruction is part of a bundle, the other instructions in the 984 /// bundle will still be bundled after removing the single instruction. 985 instr_iterator erase(instr_iterator I); 986 987 /// Remove an instruction from the instruction list and delete it. 988 /// 989 /// If the instruction is part of a bundle, the other instructions in the 990 /// bundle will still be bundled after removing the single instruction. 991 instr_iterator erase_instr(MachineInstr *I) { 992 return erase(instr_iterator(I)); 993 } 994 995 /// Remove a range of instructions from the instruction list and delete them. 996 iterator erase(iterator I, iterator E) { 997 return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); 998 } 999 1000 /// Remove an instruction or bundle from the instruction list and delete it. 1001 /// 1002 /// If I points to a bundle of instructions, they are all erased. 1003 iterator erase(iterator I) { 1004 return erase(I, std::next(I)); 1005 } 1006 1007 /// Remove an instruction from the instruction list and delete it. 1008 /// 1009 /// If I is the head of a bundle of instructions, the whole bundle will be 1010 /// erased. 1011 iterator erase(MachineInstr *I) { 1012 return erase(iterator(I)); 1013 } 1014 1015 /// Remove the unbundled instruction from the instruction list without 1016 /// deleting it. 1017 /// 1018 /// This function can not be used to remove bundled instructions, use 1019 /// remove_instr to remove individual instructions from a bundle. 1020 MachineInstr *remove(MachineInstr *I) { 1021 assert(!I->isBundled() && "Cannot remove bundled instructions"); 1022 return Insts.remove(instr_iterator(I)); 1023 } 1024 1025 /// Remove the possibly bundled instruction from the instruction list 1026 /// without deleting it. 1027 /// 1028 /// If the instruction is part of a bundle, the other instructions in the 1029 /// bundle will still be bundled after removing the single instruction. 1030 MachineInstr *remove_instr(MachineInstr *I); 1031 1032 void clear() { 1033 Insts.clear(); 1034 } 1035 1036 /// Take an instruction from MBB 'Other' at the position From, and insert it 1037 /// into this MBB right before 'Where'. 1038 /// 1039 /// If From points to a bundle of instructions, the whole bundle is moved. 1040 void splice(iterator Where, MachineBasicBlock *Other, iterator From) { 1041 // The range splice() doesn't allow noop moves, but this one does. 1042 if (Where != From) 1043 splice(Where, Other, From, std::next(From)); 1044 } 1045 1046 /// Take a block of instructions from MBB 'Other' in the range [From, To), 1047 /// and insert them into this MBB right before 'Where'. 1048 /// 1049 /// The instruction at 'Where' must not be included in the range of 1050 /// instructions to move. 1051 void splice(iterator Where, MachineBasicBlock *Other, 1052 iterator From, iterator To) { 1053 Insts.splice(Where.getInstrIterator(), Other->Insts, 1054 From.getInstrIterator(), To.getInstrIterator()); 1055 } 1056 1057 /// This method unlinks 'this' from the containing function, and returns it, 1058 /// but does not delete it. 1059 MachineBasicBlock *removeFromParent(); 1060 1061 /// This method unlinks 'this' from the containing function and deletes it. 1062 void eraseFromParent(); 1063 1064 /// Given a machine basic block that branched to 'Old', change the code and 1065 /// CFG so that it branches to 'New' instead. 1066 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1067 1068 /// Update all phi nodes in this basic block to refer to basic block \p New 1069 /// instead of basic block \p Old. 1070 void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New); 1071 1072 /// Find the next valid DebugLoc starting at MBBI, skipping any debug 1073 /// instructions. Return UnknownLoc if there is none. 1074 DebugLoc findDebugLoc(instr_iterator MBBI); 1075 DebugLoc findDebugLoc(iterator MBBI) { 1076 return findDebugLoc(MBBI.getInstrIterator()); 1077 } 1078 1079 /// Has exact same behavior as @ref findDebugLoc (it also searches towards the 1080 /// end of this MBB) except that this function takes a reverse iterator to 1081 /// identify the starting MI. 1082 DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI); 1083 DebugLoc rfindDebugLoc(reverse_iterator MBBI) { 1084 return rfindDebugLoc(MBBI.getInstrIterator()); 1085 } 1086 1087 /// Find the previous valid DebugLoc preceding MBBI, skipping any debug 1088 /// instructions. It is possible to find the last DebugLoc in the MBB using 1089 /// findPrevDebugLoc(instr_end()). Return UnknownLoc if there is none. 1090 DebugLoc findPrevDebugLoc(instr_iterator MBBI); 1091 DebugLoc findPrevDebugLoc(iterator MBBI) { 1092 return findPrevDebugLoc(MBBI.getInstrIterator()); 1093 } 1094 1095 /// Has exact same behavior as @ref findPrevDebugLoc (it also searches towards 1096 /// the beginning of this MBB) except that this function takes reverse 1097 /// iterator to identify the starting MI. A minor difference compared to 1098 /// findPrevDebugLoc is that we can't start scanning at "instr_end". 1099 DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI); 1100 DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) { 1101 return rfindPrevDebugLoc(MBBI.getInstrIterator()); 1102 } 1103 1104 /// Find and return the merged DebugLoc of the branch instructions of the 1105 /// block. Return UnknownLoc if there is none. 1106 DebugLoc findBranchDebugLoc(); 1107 1108 /// Possible outcome of a register liveness query to computeRegisterLiveness() 1109 enum LivenessQueryResult { 1110 LQR_Live, ///< Register is known to be (at least partially) live. 1111 LQR_Dead, ///< Register is known to be fully dead. 1112 LQR_Unknown ///< Register liveness not decidable from local neighborhood. 1113 }; 1114 1115 /// Return whether (physical) register \p Reg has been defined and not 1116 /// killed as of just before \p Before. 1117 /// 1118 /// Search is localised to a neighborhood of \p Neighborhood instructions 1119 /// before (searching for defs or kills) and \p Neighborhood instructions 1120 /// after (searching just for defs) \p Before. 1121 /// 1122 /// \p Reg must be a physical register. 1123 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, 1124 MCRegister Reg, 1125 const_iterator Before, 1126 unsigned Neighborhood = 10) const; 1127 1128 // Debugging methods. 1129 void dump() const; 1130 void print(raw_ostream &OS, const SlotIndexes * = nullptr, 1131 bool IsStandalone = true) const; 1132 void print(raw_ostream &OS, ModuleSlotTracker &MST, 1133 const SlotIndexes * = nullptr, bool IsStandalone = true) const; 1134 1135 enum PrintNameFlag { 1136 PrintNameIr = (1 << 0), ///< Add IR name where available 1137 PrintNameAttributes = (1 << 1), ///< Print attributes 1138 }; 1139 1140 void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr, 1141 ModuleSlotTracker *moduleSlotTracker = nullptr) const; 1142 1143 // Printing method used by LoopInfo. 1144 void printAsOperand(raw_ostream &OS, bool PrintType = true) const; 1145 1146 /// MachineBasicBlocks are uniquely numbered at the function level, unless 1147 /// they're not in a MachineFunction yet, in which case this will return -1. 1148 int getNumber() const { return Number; } 1149 void setNumber(int N) { Number = N; } 1150 1151 /// Return the MCSymbol for this basic block. 1152 MCSymbol *getSymbol() const; 1153 1154 /// Return the EHCatchret Symbol for this basic block. 1155 MCSymbol *getEHCatchretSymbol() const; 1156 1157 std::optional<uint64_t> getIrrLoopHeaderWeight() const { 1158 return IrrLoopHeaderWeight; 1159 } 1160 1161 void setIrrLoopHeaderWeight(uint64_t Weight) { 1162 IrrLoopHeaderWeight = Weight; 1163 } 1164 1165 /// Return probability of the edge from this block to MBB. This method should 1166 /// NOT be called directly, but by using getEdgeProbability method from 1167 /// MachineBranchProbabilityInfo class. 1168 BranchProbability getSuccProbability(const_succ_iterator Succ) const; 1169 1170 private: 1171 /// Return probability iterator corresponding to the I successor iterator. 1172 probability_iterator getProbabilityIterator(succ_iterator I); 1173 const_probability_iterator 1174 getProbabilityIterator(const_succ_iterator I) const; 1175 1176 friend class MachineBranchProbabilityInfo; 1177 friend class MIPrinter; 1178 1179 // Methods used to maintain doubly linked list of blocks... 1180 friend struct ilist_callback_traits<MachineBasicBlock>; 1181 1182 // Machine-CFG mutators 1183 1184 /// Add 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->addSuccessor instead. 1187 void addPredecessor(MachineBasicBlock *Pred); 1188 1189 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this 1190 /// unless you know what you're doing, because it doesn't update Pred's 1191 /// successors list. Use Pred->removeSuccessor instead. 1192 void removePredecessor(MachineBasicBlock *Pred); 1193 }; 1194 1195 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); 1196 1197 /// Prints a machine basic block reference. 1198 /// 1199 /// The format is: 1200 /// %bb.5 - a machine basic block with MBB.getNumber() == 5. 1201 /// 1202 /// Usage: OS << printMBBReference(MBB) << '\n'; 1203 Printable printMBBReference(const MachineBasicBlock &MBB); 1204 1205 // This is useful when building IndexedMaps keyed on basic block pointers. 1206 struct MBB2NumberFunctor { 1207 using argument_type = const MachineBasicBlock *; 1208 unsigned operator()(const MachineBasicBlock *MBB) const { 1209 return MBB->getNumber(); 1210 } 1211 }; 1212 1213 //===--------------------------------------------------------------------===// 1214 // GraphTraits specializations for machine basic block graphs (machine-CFGs) 1215 //===--------------------------------------------------------------------===// 1216 1217 // Provide specializations of GraphTraits to be able to treat a 1218 // MachineFunction as a graph of MachineBasicBlocks. 1219 // 1220 1221 template <> struct GraphTraits<MachineBasicBlock *> { 1222 using NodeRef = MachineBasicBlock *; 1223 using ChildIteratorType = MachineBasicBlock::succ_iterator; 1224 1225 static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } 1226 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1227 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1228 }; 1229 1230 template <> struct GraphTraits<const MachineBasicBlock *> { 1231 using NodeRef = const MachineBasicBlock *; 1232 using ChildIteratorType = MachineBasicBlock::const_succ_iterator; 1233 1234 static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } 1235 static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } 1236 static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } 1237 }; 1238 1239 // Provide specializations of GraphTraits to be able to treat a 1240 // MachineFunction as a graph of MachineBasicBlocks and to walk it 1241 // in inverse order. Inverse order for a function is considered 1242 // to be when traversing the predecessor edges of a MBB 1243 // instead of the successor edges. 1244 // 1245 template <> struct GraphTraits<Inverse<MachineBasicBlock*>> { 1246 using NodeRef = MachineBasicBlock *; 1247 using ChildIteratorType = MachineBasicBlock::pred_iterator; 1248 1249 static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) { 1250 return G.Graph; 1251 } 1252 1253 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1254 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1255 }; 1256 1257 template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> { 1258 using NodeRef = const MachineBasicBlock *; 1259 using ChildIteratorType = MachineBasicBlock::const_pred_iterator; 1260 1261 static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) { 1262 return G.Graph; 1263 } 1264 1265 static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } 1266 static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } 1267 }; 1268 1269 // These accessors are handy for sharing templated code between IR and MIR. 1270 inline auto successors(const MachineBasicBlock *BB) { return BB->successors(); } 1271 inline auto predecessors(const MachineBasicBlock *BB) { 1272 return BB->predecessors(); 1273 } 1274 1275 /// MachineInstrSpan provides an interface to get an iteration range 1276 /// containing the instruction it was initialized with, along with all 1277 /// those instructions inserted prior to or following that instruction 1278 /// at some point after the MachineInstrSpan is constructed. 1279 class MachineInstrSpan { 1280 MachineBasicBlock &MBB; 1281 MachineBasicBlock::iterator I, B, E; 1282 1283 public: 1284 MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB) 1285 : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), 1286 E(std::next(I)) { 1287 assert(I == BB->end() || I->getParent() == BB); 1288 } 1289 1290 MachineBasicBlock::iterator begin() { 1291 return B == MBB.end() ? MBB.begin() : std::next(B); 1292 } 1293 MachineBasicBlock::iterator end() { return E; } 1294 bool empty() { return begin() == end(); } 1295 1296 MachineBasicBlock::iterator getInitial() { return I; } 1297 }; 1298 1299 /// Increment \p It until it points to a non-debug instruction or to \p End 1300 /// and return the resulting iterator. This function should only be used 1301 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1302 /// const_instr_iterator} and the respective reverse iterators. 1303 template <typename IterT> 1304 inline IterT skipDebugInstructionsForward(IterT It, IterT End, 1305 bool SkipPseudoOp = true) { 1306 while (It != End && 1307 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1308 ++It; 1309 return It; 1310 } 1311 1312 /// Decrement \p It until it points to a non-debug instruction or to \p Begin 1313 /// and return the resulting iterator. This function should only be used 1314 /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, 1315 /// const_instr_iterator} and the respective reverse iterators. 1316 template <class IterT> 1317 inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin, 1318 bool SkipPseudoOp = true) { 1319 while (It != Begin && 1320 (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) 1321 --It; 1322 return It; 1323 } 1324 1325 /// Increment \p It, then continue incrementing it while it points to a debug 1326 /// instruction. A replacement for std::next. 1327 template <typename IterT> 1328 inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) { 1329 return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp); 1330 } 1331 1332 /// Decrement \p It, then continue decrementing it while it points to a debug 1333 /// instruction. A replacement for std::prev. 1334 template <typename IterT> 1335 inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) { 1336 return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp); 1337 } 1338 1339 /// Construct a range iterator which begins at \p It and moves forwards until 1340 /// \p End is reached, skipping any debug instructions. 1341 template <typename IterT> 1342 inline auto instructionsWithoutDebug(IterT It, IterT End, 1343 bool SkipPseudoOp = true) { 1344 return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) { 1345 return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe()); 1346 }); 1347 } 1348 1349 } // end namespace llvm 1350 1351 #endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H 1352