1 //===-- llvm/Instruction.h - Instruction class definition -------*- 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 // This file contains the declaration of the Instruction class, which is the 10 // base class for all of the LLVM instructions. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_IR_INSTRUCTION_H 15 #define LLVM_IR_INSTRUCTION_H 16 17 #include "llvm/ADT/ArrayRef.h" 18 #include "llvm/ADT/Bitfields.h" 19 #include "llvm/ADT/None.h" 20 #include "llvm/ADT/StringRef.h" 21 #include "llvm/ADT/ilist_node.h" 22 #include "llvm/IR/DebugLoc.h" 23 #include "llvm/IR/SymbolTableListTraits.h" 24 #include "llvm/IR/User.h" 25 #include "llvm/IR/Value.h" 26 #include "llvm/Support/AtomicOrdering.h" 27 #include "llvm/Support/Casting.h" 28 #include <algorithm> 29 #include <cassert> 30 #include <cstdint> 31 #include <utility> 32 33 namespace llvm { 34 35 class BasicBlock; 36 class FastMathFlags; 37 class MDNode; 38 class Module; 39 struct AAMDNodes; 40 41 template <> struct ilist_alloc_traits<Instruction> { 42 static inline void deleteNode(Instruction *V); 43 }; 44 45 class Instruction : public User, 46 public ilist_node_with_parent<Instruction, BasicBlock> { 47 BasicBlock *Parent; 48 DebugLoc DbgLoc; // 'dbg' Metadata cache. 49 50 /// Relative order of this instruction in its parent basic block. Used for 51 /// O(1) local dominance checks between instructions. 52 mutable unsigned Order = 0; 53 54 protected: 55 // The 15 first bits of `Value::SubclassData` are available for subclasses of 56 // `Instruction` to use. 57 using OpaqueField = Bitfield::Element<uint16_t, 0, 15>; 58 59 // Template alias so that all Instruction storing alignment use the same 60 // definiton. 61 // Valid alignments are powers of two from 2^0 to 2^MaxAlignmentExponent = 62 // 2^29. We store them as Log2(Alignment), so we need 5 bits to encode the 30 63 // possible values. 64 template <unsigned Offset> 65 using AlignmentBitfieldElementT = 66 typename Bitfield::Element<unsigned, Offset, 5, 67 Value::MaxAlignmentExponent>; 68 69 template <unsigned Offset> 70 using BoolBitfieldElementT = typename Bitfield::Element<bool, Offset, 1>; 71 72 template <unsigned Offset> 73 using AtomicOrderingBitfieldElementT = 74 typename Bitfield::Element<AtomicOrdering, Offset, 3, 75 AtomicOrdering::LAST>; 76 77 private: 78 // The last bit is used to store whether the instruction has metadata attached 79 // or not. 80 using HasMetadataField = Bitfield::Element<bool, 15, 1>; 81 82 protected: 83 ~Instruction(); // Use deleteValue() to delete a generic Instruction. 84 85 public: 86 Instruction(const Instruction &) = delete; 87 Instruction &operator=(const Instruction &) = delete; 88 89 /// Specialize the methods defined in Value, as we know that an instruction 90 /// can only be used by other instructions. 91 Instruction *user_back() { return cast<Instruction>(*user_begin());} 92 const Instruction *user_back() const { return cast<Instruction>(*user_begin());} 93 94 inline const BasicBlock *getParent() const { return Parent; } 95 inline BasicBlock *getParent() { return Parent; } 96 97 /// Return the module owning the function this instruction belongs to 98 /// or nullptr it the function does not have a module. 99 /// 100 /// Note: this is undefined behavior if the instruction does not have a 101 /// parent, or the parent basic block does not have a parent function. 102 const Module *getModule() const; 103 Module *getModule() { 104 return const_cast<Module *>( 105 static_cast<const Instruction *>(this)->getModule()); 106 } 107 108 /// Return the function this instruction belongs to. 109 /// 110 /// Note: it is undefined behavior to call this on an instruction not 111 /// currently inserted into a function. 112 const Function *getFunction() const; 113 Function *getFunction() { 114 return const_cast<Function *>( 115 static_cast<const Instruction *>(this)->getFunction()); 116 } 117 118 /// This method unlinks 'this' from the containing basic block, but does not 119 /// delete it. 120 void removeFromParent(); 121 122 /// This method unlinks 'this' from the containing basic block and deletes it. 123 /// 124 /// \returns an iterator pointing to the element after the erased one 125 SymbolTableList<Instruction>::iterator eraseFromParent(); 126 127 /// Insert an unlinked instruction into a basic block immediately before 128 /// the specified instruction. 129 void insertBefore(Instruction *InsertPos); 130 131 /// Insert an unlinked instruction into a basic block immediately after the 132 /// specified instruction. 133 void insertAfter(Instruction *InsertPos); 134 135 /// Unlink this instruction from its current basic block and insert it into 136 /// the basic block that MovePos lives in, right before MovePos. 137 void moveBefore(Instruction *MovePos); 138 139 /// Unlink this instruction and insert into BB before I. 140 /// 141 /// \pre I is a valid iterator into BB. 142 void moveBefore(BasicBlock &BB, SymbolTableList<Instruction>::iterator I); 143 144 /// Unlink this instruction from its current basic block and insert it into 145 /// the basic block that MovePos lives in, right after MovePos. 146 void moveAfter(Instruction *MovePos); 147 148 /// Given an instruction Other in the same basic block as this instruction, 149 /// return true if this instruction comes before Other. In this worst case, 150 /// this takes linear time in the number of instructions in the block. The 151 /// results are cached, so in common cases when the block remains unmodified, 152 /// it takes constant time. 153 bool comesBefore(const Instruction *Other) const; 154 155 //===--------------------------------------------------------------------===// 156 // Subclass classification. 157 //===--------------------------------------------------------------------===// 158 159 /// Returns a member of one of the enums like Instruction::Add. 160 unsigned getOpcode() const { return getValueID() - InstructionVal; } 161 162 const char *getOpcodeName() const { return getOpcodeName(getOpcode()); } 163 bool isTerminator() const { return isTerminator(getOpcode()); } 164 bool isUnaryOp() const { return isUnaryOp(getOpcode()); } 165 bool isBinaryOp() const { return isBinaryOp(getOpcode()); } 166 bool isIntDivRem() const { return isIntDivRem(getOpcode()); } 167 bool isShift() const { return isShift(getOpcode()); } 168 bool isCast() const { return isCast(getOpcode()); } 169 bool isFuncletPad() const { return isFuncletPad(getOpcode()); } 170 bool isExceptionalTerminator() const { 171 return isExceptionalTerminator(getOpcode()); 172 } 173 bool isIndirectTerminator() const { 174 return isIndirectTerminator(getOpcode()); 175 } 176 177 static const char* getOpcodeName(unsigned OpCode); 178 179 static inline bool isTerminator(unsigned OpCode) { 180 return OpCode >= TermOpsBegin && OpCode < TermOpsEnd; 181 } 182 183 static inline bool isUnaryOp(unsigned Opcode) { 184 return Opcode >= UnaryOpsBegin && Opcode < UnaryOpsEnd; 185 } 186 static inline bool isBinaryOp(unsigned Opcode) { 187 return Opcode >= BinaryOpsBegin && Opcode < BinaryOpsEnd; 188 } 189 190 static inline bool isIntDivRem(unsigned Opcode) { 191 return Opcode == UDiv || Opcode == SDiv || Opcode == URem || Opcode == SRem; 192 } 193 194 /// Determine if the Opcode is one of the shift instructions. 195 static inline bool isShift(unsigned Opcode) { 196 return Opcode >= Shl && Opcode <= AShr; 197 } 198 199 /// Return true if this is a logical shift left or a logical shift right. 200 inline bool isLogicalShift() const { 201 return getOpcode() == Shl || getOpcode() == LShr; 202 } 203 204 /// Return true if this is an arithmetic shift right. 205 inline bool isArithmeticShift() const { 206 return getOpcode() == AShr; 207 } 208 209 /// Determine if the Opcode is and/or/xor. 210 static inline bool isBitwiseLogicOp(unsigned Opcode) { 211 return Opcode == And || Opcode == Or || Opcode == Xor; 212 } 213 214 /// Return true if this is and/or/xor. 215 inline bool isBitwiseLogicOp() const { 216 return isBitwiseLogicOp(getOpcode()); 217 } 218 219 /// Determine if the OpCode is one of the CastInst instructions. 220 static inline bool isCast(unsigned OpCode) { 221 return OpCode >= CastOpsBegin && OpCode < CastOpsEnd; 222 } 223 224 /// Determine if the OpCode is one of the FuncletPadInst instructions. 225 static inline bool isFuncletPad(unsigned OpCode) { 226 return OpCode >= FuncletPadOpsBegin && OpCode < FuncletPadOpsEnd; 227 } 228 229 /// Returns true if the OpCode is a terminator related to exception handling. 230 static inline bool isExceptionalTerminator(unsigned OpCode) { 231 switch (OpCode) { 232 case Instruction::CatchSwitch: 233 case Instruction::CatchRet: 234 case Instruction::CleanupRet: 235 case Instruction::Invoke: 236 case Instruction::Resume: 237 return true; 238 default: 239 return false; 240 } 241 } 242 243 /// Returns true if the OpCode is a terminator with indirect targets. 244 static inline bool isIndirectTerminator(unsigned OpCode) { 245 switch (OpCode) { 246 case Instruction::IndirectBr: 247 case Instruction::CallBr: 248 return true; 249 default: 250 return false; 251 } 252 } 253 254 //===--------------------------------------------------------------------===// 255 // Metadata manipulation. 256 //===--------------------------------------------------------------------===// 257 258 /// Return true if this instruction has any metadata attached to it. 259 bool hasMetadata() const { return DbgLoc || Value::hasMetadata(); } 260 261 /// Return true if this instruction has metadata attached to it other than a 262 /// debug location. 263 bool hasMetadataOtherThanDebugLoc() const { return Value::hasMetadata(); } 264 265 /// Return true if this instruction has the given type of metadata attached. 266 bool hasMetadata(unsigned KindID) const { 267 return getMetadata(KindID) != nullptr; 268 } 269 270 /// Return true if this instruction has the given type of metadata attached. 271 bool hasMetadata(StringRef Kind) const { 272 return getMetadata(Kind) != nullptr; 273 } 274 275 /// Get the metadata of given kind attached to this Instruction. 276 /// If the metadata is not found then return null. 277 MDNode *getMetadata(unsigned KindID) const { 278 if (!hasMetadata()) return nullptr; 279 return getMetadataImpl(KindID); 280 } 281 282 /// Get the metadata of given kind attached to this Instruction. 283 /// If the metadata is not found then return null. 284 MDNode *getMetadata(StringRef Kind) const { 285 if (!hasMetadata()) return nullptr; 286 return getMetadataImpl(Kind); 287 } 288 289 /// Get all metadata attached to this Instruction. The first element of each 290 /// pair returned is the KindID, the second element is the metadata value. 291 /// This list is returned sorted by the KindID. 292 void 293 getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const { 294 if (hasMetadata()) 295 getAllMetadataImpl(MDs); 296 } 297 298 /// This does the same thing as getAllMetadata, except that it filters out the 299 /// debug location. 300 void getAllMetadataOtherThanDebugLoc( 301 SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const { 302 Value::getAllMetadata(MDs); 303 } 304 305 /// Fills the AAMDNodes structure with AA metadata from this instruction. 306 /// When Merge is true, the existing AA metadata is merged with that from this 307 /// instruction providing the most-general result. 308 void getAAMetadata(AAMDNodes &N, bool Merge = false) const; 309 310 /// Set the metadata of the specified kind to the specified node. This updates 311 /// or replaces metadata if already present, or removes it if Node is null. 312 void setMetadata(unsigned KindID, MDNode *Node); 313 void setMetadata(StringRef Kind, MDNode *Node); 314 315 /// Copy metadata from \p SrcInst to this instruction. \p WL, if not empty, 316 /// specifies the list of meta data that needs to be copied. If \p WL is 317 /// empty, all meta data will be copied. 318 void copyMetadata(const Instruction &SrcInst, 319 ArrayRef<unsigned> WL = ArrayRef<unsigned>()); 320 321 /// If the instruction has "branch_weights" MD_prof metadata and the MDNode 322 /// has three operands (including name string), swap the order of the 323 /// metadata. 324 void swapProfMetadata(); 325 326 /// Drop all unknown metadata except for debug locations. 327 /// @{ 328 /// Passes are required to drop metadata they don't understand. This is a 329 /// convenience method for passes to do so. 330 void dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs); 331 void dropUnknownNonDebugMetadata() { 332 return dropUnknownNonDebugMetadata(None); 333 } 334 void dropUnknownNonDebugMetadata(unsigned ID1) { 335 return dropUnknownNonDebugMetadata(makeArrayRef(ID1)); 336 } 337 void dropUnknownNonDebugMetadata(unsigned ID1, unsigned ID2) { 338 unsigned IDs[] = {ID1, ID2}; 339 return dropUnknownNonDebugMetadata(IDs); 340 } 341 /// @} 342 343 /// Adds an !annotation metadata node with \p Annotation to this instruction. 344 /// If this instruction already has !annotation metadata, append \p Annotation 345 /// to the existing node. 346 void addAnnotationMetadata(StringRef Annotation); 347 348 /// Sets the metadata on this instruction from the AAMDNodes structure. 349 void setAAMetadata(const AAMDNodes &N); 350 351 /// Retrieve the raw weight values of a conditional branch or select. 352 /// Returns true on success with profile weights filled in. 353 /// Returns false if no metadata or invalid metadata was found. 354 bool extractProfMetadata(uint64_t &TrueVal, uint64_t &FalseVal) const; 355 356 /// Retrieve total raw weight values of a branch. 357 /// Returns true on success with profile total weights filled in. 358 /// Returns false if no metadata was found. 359 bool extractProfTotalWeight(uint64_t &TotalVal) const; 360 361 /// Set the debug location information for this instruction. 362 void setDebugLoc(DebugLoc Loc) { DbgLoc = std::move(Loc); } 363 364 /// Return the debug location for this node as a DebugLoc. 365 const DebugLoc &getDebugLoc() const { return DbgLoc; } 366 367 /// Set or clear the nuw flag on this instruction, which must be an operator 368 /// which supports this flag. See LangRef.html for the meaning of this flag. 369 void setHasNoUnsignedWrap(bool b = true); 370 371 /// Set or clear the nsw flag on this instruction, which must be an operator 372 /// which supports this flag. See LangRef.html for the meaning of this flag. 373 void setHasNoSignedWrap(bool b = true); 374 375 /// Set or clear the exact flag on this instruction, which must be an operator 376 /// which supports this flag. See LangRef.html for the meaning of this flag. 377 void setIsExact(bool b = true); 378 379 /// Determine whether the no unsigned wrap flag is set. 380 bool hasNoUnsignedWrap() const; 381 382 /// Determine whether the no signed wrap flag is set. 383 bool hasNoSignedWrap() const; 384 385 /// Drops flags that may cause this instruction to evaluate to poison despite 386 /// having non-poison inputs. 387 void dropPoisonGeneratingFlags(); 388 389 /// Determine whether the exact flag is set. 390 bool isExact() const; 391 392 /// Set or clear all fast-math-flags on this instruction, which must be an 393 /// operator which supports this flag. See LangRef.html for the meaning of 394 /// this flag. 395 void setFast(bool B); 396 397 /// Set or clear the reassociation flag on this instruction, which must be 398 /// an operator which supports this flag. See LangRef.html for the meaning of 399 /// this flag. 400 void setHasAllowReassoc(bool B); 401 402 /// Set or clear the no-nans flag on this instruction, which must be an 403 /// operator which supports this flag. See LangRef.html for the meaning of 404 /// this flag. 405 void setHasNoNaNs(bool B); 406 407 /// Set or clear the no-infs flag on this instruction, which must be an 408 /// operator which supports this flag. See LangRef.html for the meaning of 409 /// this flag. 410 void setHasNoInfs(bool B); 411 412 /// Set or clear the no-signed-zeros flag on this instruction, which must be 413 /// an operator which supports this flag. See LangRef.html for the meaning of 414 /// this flag. 415 void setHasNoSignedZeros(bool B); 416 417 /// Set or clear the allow-reciprocal flag on this instruction, which must be 418 /// an operator which supports this flag. See LangRef.html for the meaning of 419 /// this flag. 420 void setHasAllowReciprocal(bool B); 421 422 /// Set or clear the allow-contract flag on this instruction, which must be 423 /// an operator which supports this flag. See LangRef.html for the meaning of 424 /// this flag. 425 void setHasAllowContract(bool B); 426 427 /// Set or clear the approximate-math-functions flag on this instruction, 428 /// which must be an operator which supports this flag. See LangRef.html for 429 /// the meaning of this flag. 430 void setHasApproxFunc(bool B); 431 432 /// Convenience function for setting multiple fast-math flags on this 433 /// instruction, which must be an operator which supports these flags. See 434 /// LangRef.html for the meaning of these flags. 435 void setFastMathFlags(FastMathFlags FMF); 436 437 /// Convenience function for transferring all fast-math flag values to this 438 /// instruction, which must be an operator which supports these flags. See 439 /// LangRef.html for the meaning of these flags. 440 void copyFastMathFlags(FastMathFlags FMF); 441 442 /// Determine whether all fast-math-flags are set. 443 bool isFast() const; 444 445 /// Determine whether the allow-reassociation flag is set. 446 bool hasAllowReassoc() const; 447 448 /// Determine whether the no-NaNs flag is set. 449 bool hasNoNaNs() const; 450 451 /// Determine whether the no-infs flag is set. 452 bool hasNoInfs() const; 453 454 /// Determine whether the no-signed-zeros flag is set. 455 bool hasNoSignedZeros() const; 456 457 /// Determine whether the allow-reciprocal flag is set. 458 bool hasAllowReciprocal() const; 459 460 /// Determine whether the allow-contract flag is set. 461 bool hasAllowContract() const; 462 463 /// Determine whether the approximate-math-functions flag is set. 464 bool hasApproxFunc() const; 465 466 /// Convenience function for getting all the fast-math flags, which must be an 467 /// operator which supports these flags. See LangRef.html for the meaning of 468 /// these flags. 469 FastMathFlags getFastMathFlags() const; 470 471 /// Copy I's fast-math flags 472 void copyFastMathFlags(const Instruction *I); 473 474 /// Convenience method to copy supported exact, fast-math, and (optionally) 475 /// wrapping flags from V to this instruction. 476 void copyIRFlags(const Value *V, bool IncludeWrapFlags = true); 477 478 /// Logical 'and' of any supported wrapping, exact, and fast-math flags of 479 /// V and this instruction. 480 void andIRFlags(const Value *V); 481 482 /// Merge 2 debug locations and apply it to the Instruction. If the 483 /// instruction is a CallIns, we need to traverse the inline chain to find 484 /// the common scope. This is not efficient for N-way merging as each time 485 /// you merge 2 iterations, you need to rebuild the hashmap to find the 486 /// common scope. However, we still choose this API because: 487 /// 1) Simplicity: it takes 2 locations instead of a list of locations. 488 /// 2) In worst case, it increases the complexity from O(N*I) to 489 /// O(2*N*I), where N is # of Instructions to merge, and I is the 490 /// maximum level of inline stack. So it is still linear. 491 /// 3) Merging of call instructions should be extremely rare in real 492 /// applications, thus the N-way merging should be in code path. 493 /// The DebugLoc attached to this instruction will be overwritten by the 494 /// merged DebugLoc. 495 void applyMergedLocation(const DILocation *LocA, const DILocation *LocB); 496 497 /// Updates the debug location given that the instruction has been hoisted 498 /// from a block to a predecessor of that block. 499 /// Note: it is undefined behavior to call this on an instruction not 500 /// currently inserted into a function. 501 void updateLocationAfterHoist(); 502 503 /// Drop the instruction's debug location. This does not guarantee removal 504 /// of the !dbg source location attachment, as it must set a line 0 location 505 /// with scope information attached on call instructions. To guarantee 506 /// removal of the !dbg attachment, use the \ref setDebugLoc() API. 507 /// Note: it is undefined behavior to call this on an instruction not 508 /// currently inserted into a function. 509 void dropLocation(); 510 511 private: 512 // These are all implemented in Metadata.cpp. 513 MDNode *getMetadataImpl(unsigned KindID) const; 514 MDNode *getMetadataImpl(StringRef Kind) const; 515 void 516 getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned, MDNode *>> &) const; 517 518 public: 519 //===--------------------------------------------------------------------===// 520 // Predicates and helper methods. 521 //===--------------------------------------------------------------------===// 522 523 /// Return true if the instruction is associative: 524 /// 525 /// Associative operators satisfy: x op (y op z) === (x op y) op z 526 /// 527 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative. 528 /// 529 bool isAssociative() const LLVM_READONLY; 530 static bool isAssociative(unsigned Opcode) { 531 return Opcode == And || Opcode == Or || Opcode == Xor || 532 Opcode == Add || Opcode == Mul; 533 } 534 535 /// Return true if the instruction is commutative: 536 /// 537 /// Commutative operators satisfy: (x op y) === (y op x) 538 /// 539 /// In LLVM, these are the commutative operators, plus SetEQ and SetNE, when 540 /// applied to any type. 541 /// 542 bool isCommutative() const LLVM_READONLY; 543 static bool isCommutative(unsigned Opcode) { 544 switch (Opcode) { 545 case Add: case FAdd: 546 case Mul: case FMul: 547 case And: case Or: case Xor: 548 return true; 549 default: 550 return false; 551 } 552 } 553 554 /// Return true if the instruction is idempotent: 555 /// 556 /// Idempotent operators satisfy: x op x === x 557 /// 558 /// In LLVM, the And and Or operators are idempotent. 559 /// 560 bool isIdempotent() const { return isIdempotent(getOpcode()); } 561 static bool isIdempotent(unsigned Opcode) { 562 return Opcode == And || Opcode == Or; 563 } 564 565 /// Return true if the instruction is nilpotent: 566 /// 567 /// Nilpotent operators satisfy: x op x === Id, 568 /// 569 /// where Id is the identity for the operator, i.e. a constant such that 570 /// x op Id === x and Id op x === x for all x. 571 /// 572 /// In LLVM, the Xor operator is nilpotent. 573 /// 574 bool isNilpotent() const { return isNilpotent(getOpcode()); } 575 static bool isNilpotent(unsigned Opcode) { 576 return Opcode == Xor; 577 } 578 579 /// Return true if this instruction may modify memory. 580 bool mayWriteToMemory() const; 581 582 /// Return true if this instruction may read memory. 583 bool mayReadFromMemory() const; 584 585 /// Return true if this instruction may read or write memory. 586 bool mayReadOrWriteMemory() const { 587 return mayReadFromMemory() || mayWriteToMemory(); 588 } 589 590 /// Return true if this instruction has an AtomicOrdering of unordered or 591 /// higher. 592 bool isAtomic() const; 593 594 /// Return true if this atomic instruction loads from memory. 595 bool hasAtomicLoad() const; 596 597 /// Return true if this atomic instruction stores to memory. 598 bool hasAtomicStore() const; 599 600 /// Return true if this instruction has a volatile memory access. 601 bool isVolatile() const; 602 603 /// Return true if this instruction may throw an exception. 604 bool mayThrow() const; 605 606 /// Return true if this instruction behaves like a memory fence: it can load 607 /// or store to memory location without being given a memory location. 608 bool isFenceLike() const { 609 switch (getOpcode()) { 610 default: 611 return false; 612 // This list should be kept in sync with the list in mayWriteToMemory for 613 // all opcodes which don't have a memory location. 614 case Instruction::Fence: 615 case Instruction::CatchPad: 616 case Instruction::CatchRet: 617 case Instruction::Call: 618 case Instruction::Invoke: 619 return true; 620 } 621 } 622 623 /// Return true if the instruction may have side effects. 624 /// 625 /// Note that this does not consider malloc and alloca to have side 626 /// effects because the newly allocated memory is completely invisible to 627 /// instructions which don't use the returned value. For cases where this 628 /// matters, isSafeToSpeculativelyExecute may be more appropriate. 629 bool mayHaveSideEffects() const { return mayWriteToMemory() || mayThrow(); } 630 631 /// Return true if the instruction can be removed if the result is unused. 632 /// 633 /// When constant folding some instructions cannot be removed even if their 634 /// results are unused. Specifically terminator instructions and calls that 635 /// may have side effects cannot be removed without semantically changing the 636 /// generated program. 637 bool isSafeToRemove() const; 638 639 /// Return true if the instruction will return (unwinding is considered as 640 /// a form of returning control flow here). 641 bool willReturn() const; 642 643 /// Return true if the instruction is a variety of EH-block. 644 bool isEHPad() const { 645 switch (getOpcode()) { 646 case Instruction::CatchSwitch: 647 case Instruction::CatchPad: 648 case Instruction::CleanupPad: 649 case Instruction::LandingPad: 650 return true; 651 default: 652 return false; 653 } 654 } 655 656 /// Return true if the instruction is a llvm.lifetime.start or 657 /// llvm.lifetime.end marker. 658 bool isLifetimeStartOrEnd() const; 659 660 /// Return true if the instruction is a llvm.launder.invariant.group or 661 /// llvm.strip.invariant.group. 662 bool isLaunderOrStripInvariantGroup() const; 663 664 /// Return true if the instruction is a DbgInfoIntrinsic or PseudoProbeInst. 665 bool isDebugOrPseudoInst() const; 666 667 /// Return a pointer to the next non-debug instruction in the same basic 668 /// block as 'this', or nullptr if no such instruction exists. Skip any pseudo 669 /// operations if \c SkipPseudoOp is true. 670 const Instruction * 671 getNextNonDebugInstruction(bool SkipPseudoOp = false) const; 672 Instruction *getNextNonDebugInstruction(bool SkipPseudoOp = false) { 673 return const_cast<Instruction *>( 674 static_cast<const Instruction *>(this)->getNextNonDebugInstruction( 675 SkipPseudoOp)); 676 } 677 678 /// Return a pointer to the previous non-debug instruction in the same basic 679 /// block as 'this', or nullptr if no such instruction exists. Skip any pseudo 680 /// operations if \c SkipPseudoOp is true. 681 const Instruction * 682 getPrevNonDebugInstruction(bool SkipPseudoOp = false) const; 683 Instruction *getPrevNonDebugInstruction(bool SkipPseudoOp = false) { 684 return const_cast<Instruction *>( 685 static_cast<const Instruction *>(this)->getPrevNonDebugInstruction( 686 SkipPseudoOp)); 687 } 688 689 /// Create a copy of 'this' instruction that is identical in all ways except 690 /// the following: 691 /// * The instruction has no parent 692 /// * The instruction has no name 693 /// 694 Instruction *clone() const; 695 696 /// Return true if the specified instruction is exactly identical to the 697 /// current one. This means that all operands match and any extra information 698 /// (e.g. load is volatile) agree. 699 bool isIdenticalTo(const Instruction *I) const; 700 701 /// This is like isIdenticalTo, except that it ignores the 702 /// SubclassOptionalData flags, which may specify conditions under which the 703 /// instruction's result is undefined. 704 bool isIdenticalToWhenDefined(const Instruction *I) const; 705 706 /// When checking for operation equivalence (using isSameOperationAs) it is 707 /// sometimes useful to ignore certain attributes. 708 enum OperationEquivalenceFlags { 709 /// Check for equivalence ignoring load/store alignment. 710 CompareIgnoringAlignment = 1<<0, 711 /// Check for equivalence treating a type and a vector of that type 712 /// as equivalent. 713 CompareUsingScalarTypes = 1<<1 714 }; 715 716 /// This function determines if the specified instruction executes the same 717 /// operation as the current one. This means that the opcodes, type, operand 718 /// types and any other factors affecting the operation must be the same. This 719 /// is similar to isIdenticalTo except the operands themselves don't have to 720 /// be identical. 721 /// @returns true if the specified instruction is the same operation as 722 /// the current one. 723 /// Determine if one instruction is the same operation as another. 724 bool isSameOperationAs(const Instruction *I, unsigned flags = 0) const; 725 726 /// Return true if there are any uses of this instruction in blocks other than 727 /// the specified block. Note that PHI nodes are considered to evaluate their 728 /// operands in the corresponding predecessor block. 729 bool isUsedOutsideOfBlock(const BasicBlock *BB) const; 730 731 /// Return the number of successors that this instruction has. The instruction 732 /// must be a terminator. 733 unsigned getNumSuccessors() const; 734 735 /// Return the specified successor. This instruction must be a terminator. 736 BasicBlock *getSuccessor(unsigned Idx) const; 737 738 /// Update the specified successor to point at the provided block. This 739 /// instruction must be a terminator. 740 void setSuccessor(unsigned Idx, BasicBlock *BB); 741 742 /// Replace specified successor OldBB to point at the provided block. 743 /// This instruction must be a terminator. 744 void replaceSuccessorWith(BasicBlock *OldBB, BasicBlock *NewBB); 745 746 /// Methods for support type inquiry through isa, cast, and dyn_cast: 747 static bool classof(const Value *V) { 748 return V->getValueID() >= Value::InstructionVal; 749 } 750 751 //---------------------------------------------------------------------- 752 // Exported enumerations. 753 // 754 enum TermOps { // These terminate basic blocks 755 #define FIRST_TERM_INST(N) TermOpsBegin = N, 756 #define HANDLE_TERM_INST(N, OPC, CLASS) OPC = N, 757 #define LAST_TERM_INST(N) TermOpsEnd = N+1 758 #include "llvm/IR/Instruction.def" 759 }; 760 761 enum UnaryOps { 762 #define FIRST_UNARY_INST(N) UnaryOpsBegin = N, 763 #define HANDLE_UNARY_INST(N, OPC, CLASS) OPC = N, 764 #define LAST_UNARY_INST(N) UnaryOpsEnd = N+1 765 #include "llvm/IR/Instruction.def" 766 }; 767 768 enum BinaryOps { 769 #define FIRST_BINARY_INST(N) BinaryOpsBegin = N, 770 #define HANDLE_BINARY_INST(N, OPC, CLASS) OPC = N, 771 #define LAST_BINARY_INST(N) BinaryOpsEnd = N+1 772 #include "llvm/IR/Instruction.def" 773 }; 774 775 enum MemoryOps { 776 #define FIRST_MEMORY_INST(N) MemoryOpsBegin = N, 777 #define HANDLE_MEMORY_INST(N, OPC, CLASS) OPC = N, 778 #define LAST_MEMORY_INST(N) MemoryOpsEnd = N+1 779 #include "llvm/IR/Instruction.def" 780 }; 781 782 enum CastOps { 783 #define FIRST_CAST_INST(N) CastOpsBegin = N, 784 #define HANDLE_CAST_INST(N, OPC, CLASS) OPC = N, 785 #define LAST_CAST_INST(N) CastOpsEnd = N+1 786 #include "llvm/IR/Instruction.def" 787 }; 788 789 enum FuncletPadOps { 790 #define FIRST_FUNCLETPAD_INST(N) FuncletPadOpsBegin = N, 791 #define HANDLE_FUNCLETPAD_INST(N, OPC, CLASS) OPC = N, 792 #define LAST_FUNCLETPAD_INST(N) FuncletPadOpsEnd = N+1 793 #include "llvm/IR/Instruction.def" 794 }; 795 796 enum OtherOps { 797 #define FIRST_OTHER_INST(N) OtherOpsBegin = N, 798 #define HANDLE_OTHER_INST(N, OPC, CLASS) OPC = N, 799 #define LAST_OTHER_INST(N) OtherOpsEnd = N+1 800 #include "llvm/IR/Instruction.def" 801 }; 802 803 private: 804 friend class SymbolTableListTraits<Instruction>; 805 friend class BasicBlock; // For renumbering. 806 807 // Shadow Value::setValueSubclassData with a private forwarding method so that 808 // subclasses cannot accidentally use it. 809 void setValueSubclassData(unsigned short D) { 810 Value::setValueSubclassData(D); 811 } 812 813 unsigned short getSubclassDataFromValue() const { 814 return Value::getSubclassDataFromValue(); 815 } 816 817 void setParent(BasicBlock *P); 818 819 protected: 820 // Instruction subclasses can stick up to 15 bits of stuff into the 821 // SubclassData field of instruction with these members. 822 823 template <typename BitfieldElement> 824 typename BitfieldElement::Type getSubclassData() const { 825 static_assert( 826 std::is_same<BitfieldElement, HasMetadataField>::value || 827 !Bitfield::isOverlapping<BitfieldElement, HasMetadataField>(), 828 "Must not overlap with the metadata bit"); 829 return Bitfield::get<BitfieldElement>(getSubclassDataFromValue()); 830 } 831 832 template <typename BitfieldElement> 833 void setSubclassData(typename BitfieldElement::Type Value) { 834 static_assert( 835 std::is_same<BitfieldElement, HasMetadataField>::value || 836 !Bitfield::isOverlapping<BitfieldElement, HasMetadataField>(), 837 "Must not overlap with the metadata bit"); 838 auto Storage = getSubclassDataFromValue(); 839 Bitfield::set<BitfieldElement>(Storage, Value); 840 setValueSubclassData(Storage); 841 } 842 843 Instruction(Type *Ty, unsigned iType, Use *Ops, unsigned NumOps, 844 Instruction *InsertBefore = nullptr); 845 Instruction(Type *Ty, unsigned iType, Use *Ops, unsigned NumOps, 846 BasicBlock *InsertAtEnd); 847 848 private: 849 /// Create a copy of this instruction. 850 Instruction *cloneImpl() const; 851 }; 852 853 inline void ilist_alloc_traits<Instruction>::deleteNode(Instruction *V) { 854 V->deleteValue(); 855 } 856 857 } // end namespace llvm 858 859 #endif // LLVM_IR_INSTRUCTION_H 860