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/StringRef.h" 20 #include "llvm/ADT/ilist_node.h" 21 #include "llvm/IR/DebugLoc.h" 22 #include "llvm/IR/SymbolTableListTraits.h" 23 #include "llvm/IR/User.h" 24 #include "llvm/IR/Value.h" 25 #include "llvm/Support/AtomicOrdering.h" 26 #include <cstdint> 27 #include <utility> 28 29 namespace llvm { 30 31 class BasicBlock; 32 class FastMathFlags; 33 class MDNode; 34 class Module; 35 struct AAMDNodes; 36 37 template <> struct ilist_alloc_traits<Instruction> { 38 static inline void deleteNode(Instruction *V); 39 }; 40 41 class Instruction : public User, 42 public ilist_node_with_parent<Instruction, BasicBlock> { 43 BasicBlock *Parent; 44 DebugLoc DbgLoc; // 'dbg' Metadata cache. 45 46 /// Relative order of this instruction in its parent basic block. Used for 47 /// O(1) local dominance checks between instructions. 48 mutable unsigned Order = 0; 49 50 protected: 51 // The 15 first bits of `Value::SubclassData` are available for subclasses of 52 // `Instruction` to use. 53 using OpaqueField = Bitfield::Element<uint16_t, 0, 15>; 54 55 // Template alias so that all Instruction storing alignment use the same 56 // definiton. 57 // Valid alignments are powers of two from 2^0 to 2^MaxAlignmentExponent = 58 // 2^32. We store them as Log2(Alignment), so we need 6 bits to encode the 33 59 // possible values. 60 template <unsigned Offset> 61 using AlignmentBitfieldElementT = 62 typename Bitfield::Element<unsigned, Offset, 6, 63 Value::MaxAlignmentExponent>; 64 65 template <unsigned Offset> 66 using BoolBitfieldElementT = typename Bitfield::Element<bool, Offset, 1>; 67 68 template <unsigned Offset> 69 using AtomicOrderingBitfieldElementT = 70 typename Bitfield::Element<AtomicOrdering, Offset, 3, 71 AtomicOrdering::LAST>; 72 73 private: 74 // The last bit is used to store whether the instruction has metadata attached 75 // or not. 76 using HasMetadataField = Bitfield::Element<bool, 15, 1>; 77 78 protected: 79 ~Instruction(); // Use deleteValue() to delete a generic Instruction. 80 81 public: 82 Instruction(const Instruction &) = delete; 83 Instruction &operator=(const Instruction &) = delete; 84 85 /// Specialize the methods defined in Value, as we know that an instruction 86 /// can only be used by other instructions. 87 Instruction *user_back() { return cast<Instruction>(*user_begin());} 88 const Instruction *user_back() const { return cast<Instruction>(*user_begin());} 89 90 inline const BasicBlock *getParent() const { return Parent; } 91 inline BasicBlock *getParent() { return Parent; } 92 93 /// Return the module owning the function this instruction belongs to 94 /// or nullptr it the function does not have a module. 95 /// 96 /// Note: this is undefined behavior if the instruction does not have a 97 /// parent, or the parent basic block does not have a parent function. 98 const Module *getModule() const; 99 Module *getModule() { 100 return const_cast<Module *>( 101 static_cast<const Instruction *>(this)->getModule()); 102 } 103 104 /// Return the function this instruction belongs to. 105 /// 106 /// Note: it is undefined behavior to call this on an instruction not 107 /// currently inserted into a function. 108 const Function *getFunction() const; 109 Function *getFunction() { 110 return const_cast<Function *>( 111 static_cast<const Instruction *>(this)->getFunction()); 112 } 113 114 /// This method unlinks 'this' from the containing basic block, but does not 115 /// delete it. 116 void removeFromParent(); 117 118 /// This method unlinks 'this' from the containing basic block and deletes it. 119 /// 120 /// \returns an iterator pointing to the element after the erased one 121 SymbolTableList<Instruction>::iterator eraseFromParent(); 122 123 /// Insert an unlinked instruction into a basic block immediately before 124 /// the specified instruction. 125 void insertBefore(Instruction *InsertPos); 126 127 /// Insert an unlinked instruction into a basic block immediately after the 128 /// specified instruction. 129 void insertAfter(Instruction *InsertPos); 130 131 /// Inserts an unlinked instruction into \p ParentBB at position \p It and 132 /// returns the iterator of the inserted instruction. 133 SymbolTableList<Instruction>::iterator 134 insertInto(BasicBlock *ParentBB, SymbolTableList<Instruction>::iterator It); 135 136 /// Unlink this instruction from its current basic block and insert it into 137 /// the basic block that MovePos lives in, right before MovePos. 138 void moveBefore(Instruction *MovePos); 139 140 /// Unlink this instruction and insert into BB before I. 141 /// 142 /// \pre I is a valid iterator into BB. 143 void moveBefore(BasicBlock &BB, SymbolTableList<Instruction>::iterator I); 144 145 /// Unlink this instruction from its current basic block and insert it into 146 /// the basic block that MovePos lives in, right after MovePos. 147 void moveAfter(Instruction *MovePos); 148 149 /// Given an instruction Other in the same basic block as this instruction, 150 /// return true if this instruction comes before Other. In this worst case, 151 /// this takes linear time in the number of instructions in the block. The 152 /// results are cached, so in common cases when the block remains unmodified, 153 /// it takes constant time. 154 bool comesBefore(const Instruction *Other) const; 155 156 /// Get the first insertion point at which the result of this instruction 157 /// is defined. This is *not* the directly following instruction in a number 158 /// of cases, e.g. phi nodes or terminators that return values. This function 159 /// may return null if the insertion after the definition is not possible, 160 /// e.g. due to a catchswitch terminator. 161 Instruction *getInsertionPointAfterDef(); 162 163 //===--------------------------------------------------------------------===// 164 // Subclass classification. 165 //===--------------------------------------------------------------------===// 166 167 /// Returns a member of one of the enums like Instruction::Add. 168 unsigned getOpcode() const { return getValueID() - InstructionVal; } 169 170 const char *getOpcodeName() const { return getOpcodeName(getOpcode()); } 171 bool isTerminator() const { return isTerminator(getOpcode()); } 172 bool isUnaryOp() const { return isUnaryOp(getOpcode()); } 173 bool isBinaryOp() const { return isBinaryOp(getOpcode()); } 174 bool isIntDivRem() const { return isIntDivRem(getOpcode()); } 175 bool isShift() const { return isShift(getOpcode()); } 176 bool isCast() const { return isCast(getOpcode()); } 177 bool isFuncletPad() const { return isFuncletPad(getOpcode()); } 178 bool isExceptionalTerminator() const { 179 return isExceptionalTerminator(getOpcode()); 180 } 181 182 /// It checks if this instruction is the only user of at least one of 183 /// its operands. 184 bool isOnlyUserOfAnyOperand(); 185 186 static const char* getOpcodeName(unsigned OpCode); 187 188 static inline bool isTerminator(unsigned OpCode) { 189 return OpCode >= TermOpsBegin && OpCode < TermOpsEnd; 190 } 191 192 static inline bool isUnaryOp(unsigned Opcode) { 193 return Opcode >= UnaryOpsBegin && Opcode < UnaryOpsEnd; 194 } 195 static inline bool isBinaryOp(unsigned Opcode) { 196 return Opcode >= BinaryOpsBegin && Opcode < BinaryOpsEnd; 197 } 198 199 static inline bool isIntDivRem(unsigned Opcode) { 200 return Opcode == UDiv || Opcode == SDiv || Opcode == URem || Opcode == SRem; 201 } 202 203 /// Determine if the Opcode is one of the shift instructions. 204 static inline bool isShift(unsigned Opcode) { 205 return Opcode >= Shl && Opcode <= AShr; 206 } 207 208 /// Return true if this is a logical shift left or a logical shift right. 209 inline bool isLogicalShift() const { 210 return getOpcode() == Shl || getOpcode() == LShr; 211 } 212 213 /// Return true if this is an arithmetic shift right. 214 inline bool isArithmeticShift() const { 215 return getOpcode() == AShr; 216 } 217 218 /// Determine if the Opcode is and/or/xor. 219 static inline bool isBitwiseLogicOp(unsigned Opcode) { 220 return Opcode == And || Opcode == Or || Opcode == Xor; 221 } 222 223 /// Return true if this is and/or/xor. 224 inline bool isBitwiseLogicOp() const { 225 return isBitwiseLogicOp(getOpcode()); 226 } 227 228 /// Determine if the OpCode is one of the CastInst instructions. 229 static inline bool isCast(unsigned OpCode) { 230 return OpCode >= CastOpsBegin && OpCode < CastOpsEnd; 231 } 232 233 /// Determine if the OpCode is one of the FuncletPadInst instructions. 234 static inline bool isFuncletPad(unsigned OpCode) { 235 return OpCode >= FuncletPadOpsBegin && OpCode < FuncletPadOpsEnd; 236 } 237 238 /// Returns true if the OpCode is a terminator related to exception handling. 239 static inline bool isExceptionalTerminator(unsigned OpCode) { 240 switch (OpCode) { 241 case Instruction::CatchSwitch: 242 case Instruction::CatchRet: 243 case Instruction::CleanupRet: 244 case Instruction::Invoke: 245 case Instruction::Resume: 246 return true; 247 default: 248 return false; 249 } 250 } 251 252 //===--------------------------------------------------------------------===// 253 // Metadata manipulation. 254 //===--------------------------------------------------------------------===// 255 256 /// Return true if this instruction has any metadata attached to it. 257 bool hasMetadata() const { return DbgLoc || Value::hasMetadata(); } 258 259 /// Return true if this instruction has metadata attached to it other than a 260 /// debug location. 261 bool hasMetadataOtherThanDebugLoc() const { return Value::hasMetadata(); } 262 263 /// Return true if this instruction has the given type of metadata attached. 264 bool hasMetadata(unsigned KindID) const { 265 return getMetadata(KindID) != nullptr; 266 } 267 268 /// Return true if this instruction has the given type of metadata attached. 269 bool hasMetadata(StringRef Kind) const { 270 return getMetadata(Kind) != nullptr; 271 } 272 273 /// Get the metadata of given kind attached to this Instruction. 274 /// If the metadata is not found then return null. 275 MDNode *getMetadata(unsigned KindID) const { 276 if (!hasMetadata()) return nullptr; 277 return getMetadataImpl(KindID); 278 } 279 280 /// Get the metadata of given kind attached to this Instruction. 281 /// If the metadata is not found then return null. 282 MDNode *getMetadata(StringRef Kind) const { 283 if (!hasMetadata()) return nullptr; 284 return getMetadataImpl(Kind); 285 } 286 287 /// Get all metadata attached to this Instruction. The first element of each 288 /// pair returned is the KindID, the second element is the metadata value. 289 /// This list is returned sorted by the KindID. 290 void 291 getAllMetadata(SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const { 292 if (hasMetadata()) 293 getAllMetadataImpl(MDs); 294 } 295 296 /// This does the same thing as getAllMetadata, except that it filters out the 297 /// debug location. 298 void getAllMetadataOtherThanDebugLoc( 299 SmallVectorImpl<std::pair<unsigned, MDNode *>> &MDs) const { 300 Value::getAllMetadata(MDs); 301 } 302 303 /// Set the metadata of the specified kind to the specified node. This updates 304 /// or replaces metadata if already present, or removes it if Node is null. 305 void setMetadata(unsigned KindID, MDNode *Node); 306 void setMetadata(StringRef Kind, MDNode *Node); 307 308 /// Copy metadata from \p SrcInst to this instruction. \p WL, if not empty, 309 /// specifies the list of meta data that needs to be copied. If \p WL is 310 /// empty, all meta data will be copied. 311 void copyMetadata(const Instruction &SrcInst, 312 ArrayRef<unsigned> WL = ArrayRef<unsigned>()); 313 314 /// If the instruction has "branch_weights" MD_prof metadata and the MDNode 315 /// has three operands (including name string), swap the order of the 316 /// metadata. 317 void swapProfMetadata(); 318 319 /// Drop all unknown metadata except for debug locations. 320 /// @{ 321 /// Passes are required to drop metadata they don't understand. This is a 322 /// convenience method for passes to do so. 323 /// dropUndefImplyingAttrsAndUnknownMetadata should be used instead of 324 /// this API if the Instruction being modified is a call. 325 void dropUnknownNonDebugMetadata(ArrayRef<unsigned> KnownIDs); 326 void dropUnknownNonDebugMetadata() { 327 return dropUnknownNonDebugMetadata(std::nullopt); 328 } 329 void dropUnknownNonDebugMetadata(unsigned ID1) { 330 return dropUnknownNonDebugMetadata(ArrayRef(ID1)); 331 } 332 void dropUnknownNonDebugMetadata(unsigned ID1, unsigned ID2) { 333 unsigned IDs[] = {ID1, ID2}; 334 return dropUnknownNonDebugMetadata(IDs); 335 } 336 /// @} 337 338 /// Adds an !annotation metadata node with \p Annotation to this instruction. 339 /// If this instruction already has !annotation metadata, append \p Annotation 340 /// to the existing node. 341 void addAnnotationMetadata(StringRef Annotation); 342 343 /// Returns the AA metadata for this instruction. 344 AAMDNodes getAAMetadata() const; 345 346 /// Sets the AA metadata on this instruction from the AAMDNodes structure. 347 void setAAMetadata(const AAMDNodes &N); 348 349 /// Retrieve total raw weight values of a branch. 350 /// Returns true on success with profile total weights filled in. 351 /// Returns false if no metadata was found. 352 bool extractProfTotalWeight(uint64_t &TotalVal) const; 353 354 /// Set the debug location information for this instruction. 355 void setDebugLoc(DebugLoc Loc) { DbgLoc = std::move(Loc); } 356 357 /// Return the debug location for this node as a DebugLoc. 358 const DebugLoc &getDebugLoc() const { return DbgLoc; } 359 360 /// Set or clear the nuw flag on this instruction, which must be an operator 361 /// which supports this flag. See LangRef.html for the meaning of this flag. 362 void setHasNoUnsignedWrap(bool b = true); 363 364 /// Set or clear the nsw flag on this instruction, which must be an operator 365 /// which supports this flag. See LangRef.html for the meaning of this flag. 366 void setHasNoSignedWrap(bool b = true); 367 368 /// Set or clear the exact flag on this instruction, which must be an operator 369 /// which supports this flag. See LangRef.html for the meaning of this flag. 370 void setIsExact(bool b = true); 371 372 /// Determine whether the no unsigned wrap flag is set. 373 bool hasNoUnsignedWrap() const LLVM_READONLY; 374 375 /// Determine whether the no signed wrap flag is set. 376 bool hasNoSignedWrap() const LLVM_READONLY; 377 378 /// Return true if this operator has flags which may cause this instruction 379 /// to evaluate to poison despite having non-poison inputs. 380 bool hasPoisonGeneratingFlags() const LLVM_READONLY; 381 382 /// Drops flags that may cause this instruction to evaluate to poison despite 383 /// having non-poison inputs. 384 void dropPoisonGeneratingFlags(); 385 386 /// Return true if this instruction has poison-generating metadata. 387 bool hasPoisonGeneratingMetadata() const LLVM_READONLY; 388 389 /// Drops metadata that may generate poison. 390 void dropPoisonGeneratingMetadata(); 391 392 /// Return true if this instruction has poison-generating flags or metadata. 393 bool hasPoisonGeneratingFlagsOrMetadata() const { 394 return hasPoisonGeneratingFlags() || hasPoisonGeneratingMetadata(); 395 } 396 397 /// Drops flags and metadata that may generate poison. 398 void dropPoisonGeneratingFlagsAndMetadata() { 399 dropPoisonGeneratingFlags(); 400 dropPoisonGeneratingMetadata(); 401 } 402 403 /// This function drops non-debug unknown metadata (through 404 /// dropUnknownNonDebugMetadata). For calls, it also drops parameter and 405 /// return attributes that can cause undefined behaviour. Both of these should 406 /// be done by passes which move instructions in IR. 407 void 408 dropUndefImplyingAttrsAndUnknownMetadata(ArrayRef<unsigned> KnownIDs = {}); 409 410 /// Determine whether the exact flag is set. 411 bool isExact() const LLVM_READONLY; 412 413 /// Set or clear all fast-math-flags on this instruction, which must be an 414 /// operator which supports this flag. See LangRef.html for the meaning of 415 /// this flag. 416 void setFast(bool B); 417 418 /// Set or clear the reassociation flag on this instruction, which must be 419 /// an operator which supports this flag. See LangRef.html for the meaning of 420 /// this flag. 421 void setHasAllowReassoc(bool B); 422 423 /// Set or clear the no-nans flag on this instruction, which must be an 424 /// operator which supports this flag. See LangRef.html for the meaning of 425 /// this flag. 426 void setHasNoNaNs(bool B); 427 428 /// Set or clear the no-infs flag on this instruction, which must be an 429 /// operator which supports this flag. See LangRef.html for the meaning of 430 /// this flag. 431 void setHasNoInfs(bool B); 432 433 /// Set or clear the no-signed-zeros flag on this instruction, which must be 434 /// an operator which supports this flag. See LangRef.html for the meaning of 435 /// this flag. 436 void setHasNoSignedZeros(bool B); 437 438 /// Set or clear the allow-reciprocal flag on this instruction, which must be 439 /// an operator which supports this flag. See LangRef.html for the meaning of 440 /// this flag. 441 void setHasAllowReciprocal(bool B); 442 443 /// Set or clear the allow-contract flag on this instruction, which must be 444 /// an operator which supports this flag. See LangRef.html for the meaning of 445 /// this flag. 446 void setHasAllowContract(bool B); 447 448 /// Set or clear the approximate-math-functions flag on this instruction, 449 /// which must be an operator which supports this flag. See LangRef.html for 450 /// the meaning of this flag. 451 void setHasApproxFunc(bool B); 452 453 /// Convenience function for setting multiple fast-math flags on this 454 /// instruction, which must be an operator which supports these flags. See 455 /// LangRef.html for the meaning of these flags. 456 void setFastMathFlags(FastMathFlags FMF); 457 458 /// Convenience function for transferring all fast-math flag values to this 459 /// instruction, which must be an operator which supports these flags. See 460 /// LangRef.html for the meaning of these flags. 461 void copyFastMathFlags(FastMathFlags FMF); 462 463 /// Determine whether all fast-math-flags are set. 464 bool isFast() const LLVM_READONLY; 465 466 /// Determine whether the allow-reassociation flag is set. 467 bool hasAllowReassoc() const LLVM_READONLY; 468 469 /// Determine whether the no-NaNs flag is set. 470 bool hasNoNaNs() const LLVM_READONLY; 471 472 /// Determine whether the no-infs flag is set. 473 bool hasNoInfs() const LLVM_READONLY; 474 475 /// Determine whether the no-signed-zeros flag is set. 476 bool hasNoSignedZeros() const LLVM_READONLY; 477 478 /// Determine whether the allow-reciprocal flag is set. 479 bool hasAllowReciprocal() const LLVM_READONLY; 480 481 /// Determine whether the allow-contract flag is set. 482 bool hasAllowContract() const LLVM_READONLY; 483 484 /// Determine whether the approximate-math-functions flag is set. 485 bool hasApproxFunc() const LLVM_READONLY; 486 487 /// Convenience function for getting all the fast-math flags, which must be an 488 /// operator which supports these flags. See LangRef.html for the meaning of 489 /// these flags. 490 FastMathFlags getFastMathFlags() const LLVM_READONLY; 491 492 /// Copy I's fast-math flags 493 void copyFastMathFlags(const Instruction *I); 494 495 /// Convenience method to copy supported exact, fast-math, and (optionally) 496 /// wrapping flags from V to this instruction. 497 void copyIRFlags(const Value *V, bool IncludeWrapFlags = true); 498 499 /// Logical 'and' of any supported wrapping, exact, and fast-math flags of 500 /// V and this instruction. 501 void andIRFlags(const Value *V); 502 503 /// Merge 2 debug locations and apply it to the Instruction. If the 504 /// instruction is a CallIns, we need to traverse the inline chain to find 505 /// the common scope. This is not efficient for N-way merging as each time 506 /// you merge 2 iterations, you need to rebuild the hashmap to find the 507 /// common scope. However, we still choose this API because: 508 /// 1) Simplicity: it takes 2 locations instead of a list of locations. 509 /// 2) In worst case, it increases the complexity from O(N*I) to 510 /// O(2*N*I), where N is # of Instructions to merge, and I is the 511 /// maximum level of inline stack. So it is still linear. 512 /// 3) Merging of call instructions should be extremely rare in real 513 /// applications, thus the N-way merging should be in code path. 514 /// The DebugLoc attached to this instruction will be overwritten by the 515 /// merged DebugLoc. 516 void applyMergedLocation(const DILocation *LocA, const DILocation *LocB); 517 518 /// Updates the debug location given that the instruction has been hoisted 519 /// from a block to a predecessor of that block. 520 /// Note: it is undefined behavior to call this on an instruction not 521 /// currently inserted into a function. 522 void updateLocationAfterHoist(); 523 524 /// Drop the instruction's debug location. This does not guarantee removal 525 /// of the !dbg source location attachment, as it must set a line 0 location 526 /// with scope information attached on call instructions. To guarantee 527 /// removal of the !dbg attachment, use the \ref setDebugLoc() API. 528 /// Note: it is undefined behavior to call this on an instruction not 529 /// currently inserted into a function. 530 void dropLocation(); 531 532 /// Merge the DIAssignID metadata from this instruction and those attached to 533 /// instructions in \p SourceInstructions. This process performs a RAUW on 534 /// the MetadataAsValue uses of the merged DIAssignID nodes. Not every 535 /// instruction in \p SourceInstructions needs to have DIAssignID 536 /// metadata. If none of them do then nothing happens. If this instruction 537 /// does not have a DIAssignID attachment but at least one in \p 538 /// SourceInstructions does then the merged one will be attached to 539 /// it. However, instructions without attachments in \p SourceInstructions 540 /// are not modified. 541 void mergeDIAssignID(ArrayRef<const Instruction *> SourceInstructions); 542 543 private: 544 // These are all implemented in Metadata.cpp. 545 MDNode *getMetadataImpl(unsigned KindID) const; 546 MDNode *getMetadataImpl(StringRef Kind) const; 547 void 548 getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned, MDNode *>> &) const; 549 550 /// Update the LLVMContext ID-to-Instruction(s) mapping. If \p ID is nullptr 551 /// then clear the mapping for this instruction. 552 void updateDIAssignIDMapping(DIAssignID *ID); 553 554 public: 555 //===--------------------------------------------------------------------===// 556 // Predicates and helper methods. 557 //===--------------------------------------------------------------------===// 558 559 /// Return true if the instruction is associative: 560 /// 561 /// Associative operators satisfy: x op (y op z) === (x op y) op z 562 /// 563 /// In LLVM, the Add, Mul, And, Or, and Xor operators are associative. 564 /// 565 bool isAssociative() const LLVM_READONLY; 566 static bool isAssociative(unsigned Opcode) { 567 return Opcode == And || Opcode == Or || Opcode == Xor || 568 Opcode == Add || Opcode == Mul; 569 } 570 571 /// Return true if the instruction is commutative: 572 /// 573 /// Commutative operators satisfy: (x op y) === (y op x) 574 /// 575 /// In LLVM, these are the commutative operators, plus SetEQ and SetNE, when 576 /// applied to any type. 577 /// 578 bool isCommutative() const LLVM_READONLY; 579 static bool isCommutative(unsigned Opcode) { 580 switch (Opcode) { 581 case Add: case FAdd: 582 case Mul: case FMul: 583 case And: case Or: case Xor: 584 return true; 585 default: 586 return false; 587 } 588 } 589 590 /// Return true if the instruction is idempotent: 591 /// 592 /// Idempotent operators satisfy: x op x === x 593 /// 594 /// In LLVM, the And and Or operators are idempotent. 595 /// 596 bool isIdempotent() const { return isIdempotent(getOpcode()); } 597 static bool isIdempotent(unsigned Opcode) { 598 return Opcode == And || Opcode == Or; 599 } 600 601 /// Return true if the instruction is nilpotent: 602 /// 603 /// Nilpotent operators satisfy: x op x === Id, 604 /// 605 /// where Id is the identity for the operator, i.e. a constant such that 606 /// x op Id === x and Id op x === x for all x. 607 /// 608 /// In LLVM, the Xor operator is nilpotent. 609 /// 610 bool isNilpotent() const { return isNilpotent(getOpcode()); } 611 static bool isNilpotent(unsigned Opcode) { 612 return Opcode == Xor; 613 } 614 615 /// Return true if this instruction may modify memory. 616 bool mayWriteToMemory() const LLVM_READONLY; 617 618 /// Return true if this instruction may read memory. 619 bool mayReadFromMemory() const LLVM_READONLY; 620 621 /// Return true if this instruction may read or write memory. 622 bool mayReadOrWriteMemory() const { 623 return mayReadFromMemory() || mayWriteToMemory(); 624 } 625 626 /// Return true if this instruction has an AtomicOrdering of unordered or 627 /// higher. 628 bool isAtomic() const LLVM_READONLY; 629 630 /// Return true if this atomic instruction loads from memory. 631 bool hasAtomicLoad() const LLVM_READONLY; 632 633 /// Return true if this atomic instruction stores to memory. 634 bool hasAtomicStore() const LLVM_READONLY; 635 636 /// Return true if this instruction has a volatile memory access. 637 bool isVolatile() const LLVM_READONLY; 638 639 /// Return true if this instruction may throw an exception. 640 bool mayThrow() const LLVM_READONLY; 641 642 /// Return true if this instruction behaves like a memory fence: it can load 643 /// or store to memory location without being given a memory location. 644 bool isFenceLike() const { 645 switch (getOpcode()) { 646 default: 647 return false; 648 // This list should be kept in sync with the list in mayWriteToMemory for 649 // all opcodes which don't have a memory location. 650 case Instruction::Fence: 651 case Instruction::CatchPad: 652 case Instruction::CatchRet: 653 case Instruction::Call: 654 case Instruction::Invoke: 655 return true; 656 } 657 } 658 659 /// Return true if the instruction may have side effects. 660 /// 661 /// Side effects are: 662 /// * Writing to memory. 663 /// * Unwinding. 664 /// * Not returning (e.g. an infinite loop). 665 /// 666 /// Note that this does not consider malloc and alloca to have side 667 /// effects because the newly allocated memory is completely invisible to 668 /// instructions which don't use the returned value. For cases where this 669 /// matters, isSafeToSpeculativelyExecute may be more appropriate. 670 bool mayHaveSideEffects() const LLVM_READONLY; 671 672 /// Return true if the instruction can be removed if the result is unused. 673 /// 674 /// When constant folding some instructions cannot be removed even if their 675 /// results are unused. Specifically terminator instructions and calls that 676 /// may have side effects cannot be removed without semantically changing the 677 /// generated program. 678 bool isSafeToRemove() const LLVM_READONLY; 679 680 /// Return true if the instruction will return (unwinding is considered as 681 /// a form of returning control flow here). 682 bool willReturn() const LLVM_READONLY; 683 684 /// Return true if the instruction is a variety of EH-block. 685 bool isEHPad() const { 686 switch (getOpcode()) { 687 case Instruction::CatchSwitch: 688 case Instruction::CatchPad: 689 case Instruction::CleanupPad: 690 case Instruction::LandingPad: 691 return true; 692 default: 693 return false; 694 } 695 } 696 697 /// Return true if the instruction is a llvm.lifetime.start or 698 /// llvm.lifetime.end marker. 699 bool isLifetimeStartOrEnd() const LLVM_READONLY; 700 701 /// Return true if the instruction is a llvm.launder.invariant.group or 702 /// llvm.strip.invariant.group. 703 bool isLaunderOrStripInvariantGroup() const LLVM_READONLY; 704 705 /// Return true if the instruction is a DbgInfoIntrinsic or PseudoProbeInst. 706 bool isDebugOrPseudoInst() const LLVM_READONLY; 707 708 /// Return a pointer to the next non-debug instruction in the same basic 709 /// block as 'this', or nullptr if no such instruction exists. Skip any pseudo 710 /// operations if \c SkipPseudoOp is true. 711 const Instruction * 712 getNextNonDebugInstruction(bool SkipPseudoOp = false) const; 713 Instruction *getNextNonDebugInstruction(bool SkipPseudoOp = false) { 714 return const_cast<Instruction *>( 715 static_cast<const Instruction *>(this)->getNextNonDebugInstruction( 716 SkipPseudoOp)); 717 } 718 719 /// Return a pointer to the previous non-debug instruction in the same basic 720 /// block as 'this', or nullptr if no such instruction exists. Skip any pseudo 721 /// operations if \c SkipPseudoOp is true. 722 const Instruction * 723 getPrevNonDebugInstruction(bool SkipPseudoOp = false) const; 724 Instruction *getPrevNonDebugInstruction(bool SkipPseudoOp = false) { 725 return const_cast<Instruction *>( 726 static_cast<const Instruction *>(this)->getPrevNonDebugInstruction( 727 SkipPseudoOp)); 728 } 729 730 /// Create a copy of 'this' instruction that is identical in all ways except 731 /// the following: 732 /// * The instruction has no parent 733 /// * The instruction has no name 734 /// 735 Instruction *clone() const; 736 737 /// Return true if the specified instruction is exactly identical to the 738 /// current one. This means that all operands match and any extra information 739 /// (e.g. load is volatile) agree. 740 bool isIdenticalTo(const Instruction *I) const LLVM_READONLY; 741 742 /// This is like isIdenticalTo, except that it ignores the 743 /// SubclassOptionalData flags, which may specify conditions under which the 744 /// instruction's result is undefined. 745 bool isIdenticalToWhenDefined(const Instruction *I) const LLVM_READONLY; 746 747 /// When checking for operation equivalence (using isSameOperationAs) it is 748 /// sometimes useful to ignore certain attributes. 749 enum OperationEquivalenceFlags { 750 /// Check for equivalence ignoring load/store alignment. 751 CompareIgnoringAlignment = 1<<0, 752 /// Check for equivalence treating a type and a vector of that type 753 /// as equivalent. 754 CompareUsingScalarTypes = 1<<1 755 }; 756 757 /// This function determines if the specified instruction executes the same 758 /// operation as the current one. This means that the opcodes, type, operand 759 /// types and any other factors affecting the operation must be the same. This 760 /// is similar to isIdenticalTo except the operands themselves don't have to 761 /// be identical. 762 /// @returns true if the specified instruction is the same operation as 763 /// the current one. 764 /// Determine if one instruction is the same operation as another. 765 bool isSameOperationAs(const Instruction *I, unsigned flags = 0) const LLVM_READONLY; 766 767 /// Return true if there are any uses of this instruction in blocks other than 768 /// the specified block. Note that PHI nodes are considered to evaluate their 769 /// operands in the corresponding predecessor block. 770 bool isUsedOutsideOfBlock(const BasicBlock *BB) const LLVM_READONLY; 771 772 /// Return the number of successors that this instruction has. The instruction 773 /// must be a terminator. 774 unsigned getNumSuccessors() const LLVM_READONLY; 775 776 /// Return the specified successor. This instruction must be a terminator. 777 BasicBlock *getSuccessor(unsigned Idx) const LLVM_READONLY; 778 779 /// Update the specified successor to point at the provided block. This 780 /// instruction must be a terminator. 781 void setSuccessor(unsigned Idx, BasicBlock *BB); 782 783 /// Replace specified successor OldBB to point at the provided block. 784 /// This instruction must be a terminator. 785 void replaceSuccessorWith(BasicBlock *OldBB, BasicBlock *NewBB); 786 787 /// Methods for support type inquiry through isa, cast, and dyn_cast: 788 static bool classof(const Value *V) { 789 return V->getValueID() >= Value::InstructionVal; 790 } 791 792 //---------------------------------------------------------------------- 793 // Exported enumerations. 794 // 795 enum TermOps { // These terminate basic blocks 796 #define FIRST_TERM_INST(N) TermOpsBegin = N, 797 #define HANDLE_TERM_INST(N, OPC, CLASS) OPC = N, 798 #define LAST_TERM_INST(N) TermOpsEnd = N+1 799 #include "llvm/IR/Instruction.def" 800 }; 801 802 enum UnaryOps { 803 #define FIRST_UNARY_INST(N) UnaryOpsBegin = N, 804 #define HANDLE_UNARY_INST(N, OPC, CLASS) OPC = N, 805 #define LAST_UNARY_INST(N) UnaryOpsEnd = N+1 806 #include "llvm/IR/Instruction.def" 807 }; 808 809 enum BinaryOps { 810 #define FIRST_BINARY_INST(N) BinaryOpsBegin = N, 811 #define HANDLE_BINARY_INST(N, OPC, CLASS) OPC = N, 812 #define LAST_BINARY_INST(N) BinaryOpsEnd = N+1 813 #include "llvm/IR/Instruction.def" 814 }; 815 816 enum MemoryOps { 817 #define FIRST_MEMORY_INST(N) MemoryOpsBegin = N, 818 #define HANDLE_MEMORY_INST(N, OPC, CLASS) OPC = N, 819 #define LAST_MEMORY_INST(N) MemoryOpsEnd = N+1 820 #include "llvm/IR/Instruction.def" 821 }; 822 823 enum CastOps { 824 #define FIRST_CAST_INST(N) CastOpsBegin = N, 825 #define HANDLE_CAST_INST(N, OPC, CLASS) OPC = N, 826 #define LAST_CAST_INST(N) CastOpsEnd = N+1 827 #include "llvm/IR/Instruction.def" 828 }; 829 830 enum FuncletPadOps { 831 #define FIRST_FUNCLETPAD_INST(N) FuncletPadOpsBegin = N, 832 #define HANDLE_FUNCLETPAD_INST(N, OPC, CLASS) OPC = N, 833 #define LAST_FUNCLETPAD_INST(N) FuncletPadOpsEnd = N+1 834 #include "llvm/IR/Instruction.def" 835 }; 836 837 enum OtherOps { 838 #define FIRST_OTHER_INST(N) OtherOpsBegin = N, 839 #define HANDLE_OTHER_INST(N, OPC, CLASS) OPC = N, 840 #define LAST_OTHER_INST(N) OtherOpsEnd = N+1 841 #include "llvm/IR/Instruction.def" 842 }; 843 844 private: 845 friend class SymbolTableListTraits<Instruction>; 846 friend class BasicBlock; // For renumbering. 847 848 // Shadow Value::setValueSubclassData with a private forwarding method so that 849 // subclasses cannot accidentally use it. 850 void setValueSubclassData(unsigned short D) { 851 Value::setValueSubclassData(D); 852 } 853 854 unsigned short getSubclassDataFromValue() const { 855 return Value::getSubclassDataFromValue(); 856 } 857 858 void setParent(BasicBlock *P); 859 860 protected: 861 // Instruction subclasses can stick up to 15 bits of stuff into the 862 // SubclassData field of instruction with these members. 863 864 template <typename BitfieldElement> 865 typename BitfieldElement::Type getSubclassData() const { 866 static_assert( 867 std::is_same<BitfieldElement, HasMetadataField>::value || 868 !Bitfield::isOverlapping<BitfieldElement, HasMetadataField>(), 869 "Must not overlap with the metadata bit"); 870 return Bitfield::get<BitfieldElement>(getSubclassDataFromValue()); 871 } 872 873 template <typename BitfieldElement> 874 void setSubclassData(typename BitfieldElement::Type Value) { 875 static_assert( 876 std::is_same<BitfieldElement, HasMetadataField>::value || 877 !Bitfield::isOverlapping<BitfieldElement, HasMetadataField>(), 878 "Must not overlap with the metadata bit"); 879 auto Storage = getSubclassDataFromValue(); 880 Bitfield::set<BitfieldElement>(Storage, Value); 881 setValueSubclassData(Storage); 882 } 883 884 Instruction(Type *Ty, unsigned iType, Use *Ops, unsigned NumOps, 885 Instruction *InsertBefore = nullptr); 886 Instruction(Type *Ty, unsigned iType, Use *Ops, unsigned NumOps, 887 BasicBlock *InsertAtEnd); 888 889 private: 890 /// Create a copy of this instruction. 891 Instruction *cloneImpl() const; 892 }; 893 894 inline void ilist_alloc_traits<Instruction>::deleteNode(Instruction *V) { 895 V->deleteValue(); 896 } 897 898 } // end namespace llvm 899 900 #endif // LLVM_IR_INSTRUCTION_H 901