1 //===-- llvm/Constants.h - Constant class subclass definitions --*- 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 /// @file 10 /// This file contains the declarations for the subclasses of Constant, 11 /// which represent the different flavors of constant values that live in LLVM. 12 /// Note that Constants are immutable (once created they never change) and are 13 /// fully shared by structural equivalence. This means that two structurally 14 /// equivalent constants will always have the same address. Constants are 15 /// created on demand as needed and never deleted: thus clients don't have to 16 /// worry about the lifetime of the objects. 17 // 18 //===----------------------------------------------------------------------===// 19 20 #ifndef LLVM_IR_CONSTANTS_H 21 #define LLVM_IR_CONSTANTS_H 22 23 #include "llvm/ADT/APFloat.h" 24 #include "llvm/ADT/APInt.h" 25 #include "llvm/ADT/ArrayRef.h" 26 #include "llvm/ADT/None.h" 27 #include "llvm/ADT/Optional.h" 28 #include "llvm/ADT/STLExtras.h" 29 #include "llvm/ADT/StringRef.h" 30 #include "llvm/IR/Constant.h" 31 #include "llvm/IR/DerivedTypes.h" 32 #include "llvm/IR/OperandTraits.h" 33 #include "llvm/IR/User.h" 34 #include "llvm/IR/Value.h" 35 #include "llvm/Support/Casting.h" 36 #include "llvm/Support/Compiler.h" 37 #include "llvm/Support/ErrorHandling.h" 38 #include <cassert> 39 #include <cstddef> 40 #include <cstdint> 41 42 namespace llvm { 43 44 template <class ConstantClass> struct ConstantAggrKeyType; 45 46 /// Base class for constants with no operands. 47 /// 48 /// These constants have no operands; they represent their data directly. 49 /// Since they can be in use by unrelated modules (and are never based on 50 /// GlobalValues), it never makes sense to RAUW them. 51 class ConstantData : public Constant { 52 friend class Constant; 53 handleOperandChangeImpl(Value * From,Value * To)54 Value *handleOperandChangeImpl(Value *From, Value *To) { 55 llvm_unreachable("Constant data does not have operands!"); 56 } 57 58 protected: ConstantData(Type * Ty,ValueTy VT)59 explicit ConstantData(Type *Ty, ValueTy VT) : Constant(Ty, VT, nullptr, 0) {} 60 new(size_t s)61 void *operator new(size_t s) { return User::operator new(s, 0); } 62 63 public: 64 ConstantData(const ConstantData &) = delete; 65 66 /// Methods to support type inquiry through isa, cast, and dyn_cast. classof(const Value * V)67 static bool classof(const Value *V) { 68 return V->getValueID() >= ConstantDataFirstVal && 69 V->getValueID() <= ConstantDataLastVal; 70 } 71 }; 72 73 //===----------------------------------------------------------------------===// 74 /// This is the shared class of boolean and integer constants. This class 75 /// represents both boolean and integral constants. 76 /// Class for constant integers. 77 class ConstantInt final : public ConstantData { 78 friend class Constant; 79 80 APInt Val; 81 82 ConstantInt(IntegerType *Ty, const APInt& V); 83 84 void destroyConstantImpl(); 85 86 public: 87 ConstantInt(const ConstantInt &) = delete; 88 89 static ConstantInt *getTrue(LLVMContext &Context); 90 static ConstantInt *getFalse(LLVMContext &Context); 91 static ConstantInt *getBool(LLVMContext &Context, bool V); 92 static Constant *getTrue(Type *Ty); 93 static Constant *getFalse(Type *Ty); 94 static Constant *getBool(Type *Ty, bool V); 95 96 /// If Ty is a vector type, return a Constant with a splat of the given 97 /// value. Otherwise return a ConstantInt for the given value. 98 static Constant *get(Type *Ty, uint64_t V, bool isSigned = false); 99 100 /// Return a ConstantInt with the specified integer value for the specified 101 /// type. If the type is wider than 64 bits, the value will be zero-extended 102 /// to fit the type, unless isSigned is true, in which case the value will 103 /// be interpreted as a 64-bit signed integer and sign-extended to fit 104 /// the type. 105 /// Get a ConstantInt for a specific value. 106 static ConstantInt *get(IntegerType *Ty, uint64_t V, 107 bool isSigned = false); 108 109 /// Return a ConstantInt with the specified value for the specified type. The 110 /// value V will be canonicalized to a an unsigned APInt. Accessing it with 111 /// either getSExtValue() or getZExtValue() will yield a correctly sized and 112 /// signed value for the type Ty. 113 /// Get a ConstantInt for a specific signed value. 114 static ConstantInt *getSigned(IntegerType *Ty, int64_t V); 115 static Constant *getSigned(Type *Ty, int64_t V); 116 117 /// Return a ConstantInt with the specified value and an implied Type. The 118 /// type is the integer type that corresponds to the bit width of the value. 119 static ConstantInt *get(LLVMContext &Context, const APInt &V); 120 121 /// Return a ConstantInt constructed from the string strStart with the given 122 /// radix. 123 static ConstantInt *get(IntegerType *Ty, StringRef Str, 124 uint8_t radix); 125 126 /// If Ty is a vector type, return a Constant with a splat of the given 127 /// value. Otherwise return a ConstantInt for the given value. 128 static Constant *get(Type* Ty, const APInt& V); 129 130 /// Return the constant as an APInt value reference. This allows clients to 131 /// obtain a full-precision copy of the value. 132 /// Return the constant's value. getValue()133 inline const APInt &getValue() const { 134 return Val; 135 } 136 137 /// getBitWidth - Return the bitwidth of this constant. getBitWidth()138 unsigned getBitWidth() const { return Val.getBitWidth(); } 139 140 /// Return the constant as a 64-bit unsigned integer value after it 141 /// has been zero extended as appropriate for the type of this constant. Note 142 /// that this method can assert if the value does not fit in 64 bits. 143 /// Return the zero extended value. getZExtValue()144 inline uint64_t getZExtValue() const { 145 return Val.getZExtValue(); 146 } 147 148 /// Return the constant as a 64-bit integer value after it has been sign 149 /// extended as appropriate for the type of this constant. Note that 150 /// this method can assert if the value does not fit in 64 bits. 151 /// Return the sign extended value. getSExtValue()152 inline int64_t getSExtValue() const { 153 return Val.getSExtValue(); 154 } 155 156 /// Return the constant as an llvm::MaybeAlign. 157 /// Note that this method can assert if the value does not fit in 64 bits or 158 /// is not a power of two. getMaybeAlignValue()159 inline MaybeAlign getMaybeAlignValue() const { 160 return MaybeAlign(getZExtValue()); 161 } 162 163 /// Return the constant as an llvm::Align, interpreting `0` as `Align(1)`. 164 /// Note that this method can assert if the value does not fit in 64 bits or 165 /// is not a power of two. getAlignValue()166 inline Align getAlignValue() const { 167 return getMaybeAlignValue().valueOrOne(); 168 } 169 170 /// A helper method that can be used to determine if the constant contained 171 /// within is equal to a constant. This only works for very small values, 172 /// because this is all that can be represented with all types. 173 /// Determine if this constant's value is same as an unsigned char. equalsInt(uint64_t V)174 bool equalsInt(uint64_t V) const { 175 return Val == V; 176 } 177 178 /// getType - Specialize the getType() method to always return an IntegerType, 179 /// which reduces the amount of casting needed in parts of the compiler. 180 /// getType()181 inline IntegerType *getType() const { 182 return cast<IntegerType>(Value::getType()); 183 } 184 185 /// This static method returns true if the type Ty is big enough to 186 /// represent the value V. This can be used to avoid having the get method 187 /// assert when V is larger than Ty can represent. Note that there are two 188 /// versions of this method, one for unsigned and one for signed integers. 189 /// Although ConstantInt canonicalizes everything to an unsigned integer, 190 /// the signed version avoids callers having to convert a signed quantity 191 /// to the appropriate unsigned type before calling the method. 192 /// @returns true if V is a valid value for type Ty 193 /// Determine if the value is in range for the given type. 194 static bool isValueValidForType(Type *Ty, uint64_t V); 195 static bool isValueValidForType(Type *Ty, int64_t V); 196 isNegative()197 bool isNegative() const { return Val.isNegative(); } 198 199 /// This is just a convenience method to make client code smaller for a 200 /// common code. It also correctly performs the comparison without the 201 /// potential for an assertion from getZExtValue(). isZero()202 bool isZero() const { 203 return Val.isNullValue(); 204 } 205 206 /// This is just a convenience method to make client code smaller for a 207 /// common case. It also correctly performs the comparison without the 208 /// potential for an assertion from getZExtValue(). 209 /// Determine if the value is one. isOne()210 bool isOne() const { 211 return Val.isOneValue(); 212 } 213 214 /// This function will return true iff every bit in this constant is set 215 /// to true. 216 /// @returns true iff this constant's bits are all set to true. 217 /// Determine if the value is all ones. isMinusOne()218 bool isMinusOne() const { 219 return Val.isAllOnesValue(); 220 } 221 222 /// This function will return true iff this constant represents the largest 223 /// value that may be represented by the constant's type. 224 /// @returns true iff this is the largest value that may be represented 225 /// by this type. 226 /// Determine if the value is maximal. isMaxValue(bool isSigned)227 bool isMaxValue(bool isSigned) const { 228 if (isSigned) 229 return Val.isMaxSignedValue(); 230 else 231 return Val.isMaxValue(); 232 } 233 234 /// This function will return true iff this constant represents the smallest 235 /// value that may be represented by this constant's type. 236 /// @returns true if this is the smallest value that may be represented by 237 /// this type. 238 /// Determine if the value is minimal. isMinValue(bool isSigned)239 bool isMinValue(bool isSigned) const { 240 if (isSigned) 241 return Val.isMinSignedValue(); 242 else 243 return Val.isMinValue(); 244 } 245 246 /// This function will return true iff this constant represents a value with 247 /// active bits bigger than 64 bits or a value greater than the given uint64_t 248 /// value. 249 /// @returns true iff this constant is greater or equal to the given number. 250 /// Determine if the value is greater or equal to the given number. uge(uint64_t Num)251 bool uge(uint64_t Num) const { 252 return Val.uge(Num); 253 } 254 255 /// getLimitedValue - If the value is smaller than the specified limit, 256 /// return it, otherwise return the limit value. This causes the value 257 /// to saturate to the limit. 258 /// @returns the min of the value of the constant and the specified value 259 /// Get the constant's value with a saturation limit 260 uint64_t getLimitedValue(uint64_t Limit = ~0ULL) const { 261 return Val.getLimitedValue(Limit); 262 } 263 264 /// Methods to support type inquiry through isa, cast, and dyn_cast. classof(const Value * V)265 static bool classof(const Value *V) { 266 return V->getValueID() == ConstantIntVal; 267 } 268 }; 269 270 //===----------------------------------------------------------------------===// 271 /// ConstantFP - Floating Point Values [float, double] 272 /// 273 class ConstantFP final : public ConstantData { 274 friend class Constant; 275 276 APFloat Val; 277 278 ConstantFP(Type *Ty, const APFloat& V); 279 280 void destroyConstantImpl(); 281 282 public: 283 ConstantFP(const ConstantFP &) = delete; 284 285 /// Floating point negation must be implemented with f(x) = -0.0 - x. This 286 /// method returns the negative zero constant for floating point or vector 287 /// floating point types; for all other types, it returns the null value. 288 static Constant *getZeroValueForNegation(Type *Ty); 289 290 /// This returns a ConstantFP, or a vector containing a splat of a ConstantFP, 291 /// for the specified value in the specified type. This should only be used 292 /// for simple constant values like 2.0/1.0 etc, that are known-valid both as 293 /// host double and as the target format. 294 static Constant *get(Type* Ty, double V); 295 296 /// If Ty is a vector type, return a Constant with a splat of the given 297 /// value. Otherwise return a ConstantFP for the given value. 298 static Constant *get(Type *Ty, const APFloat &V); 299 300 static Constant *get(Type* Ty, StringRef Str); 301 static ConstantFP *get(LLVMContext &Context, const APFloat &V); 302 static Constant *getNaN(Type *Ty, bool Negative = false, uint64_t Payload = 0); 303 static Constant *getQNaN(Type *Ty, bool Negative = false, 304 APInt *Payload = nullptr); 305 static Constant *getSNaN(Type *Ty, bool Negative = false, 306 APInt *Payload = nullptr); 307 static Constant *getNegativeZero(Type *Ty); 308 static Constant *getInfinity(Type *Ty, bool Negative = false); 309 310 /// Return true if Ty is big enough to represent V. 311 static bool isValueValidForType(Type *Ty, const APFloat &V); getValueAPF()312 inline const APFloat &getValueAPF() const { return Val; } getValue()313 inline const APFloat &getValue() const { return Val; } 314 315 /// Return true if the value is positive or negative zero. isZero()316 bool isZero() const { return Val.isZero(); } 317 318 /// Return true if the sign bit is set. isNegative()319 bool isNegative() const { return Val.isNegative(); } 320 321 /// Return true if the value is infinity isInfinity()322 bool isInfinity() const { return Val.isInfinity(); } 323 324 /// Return true if the value is a NaN. isNaN()325 bool isNaN() const { return Val.isNaN(); } 326 327 /// We don't rely on operator== working on double values, as it returns true 328 /// for things that are clearly not equal, like -0.0 and 0.0. 329 /// As such, this method can be used to do an exact bit-for-bit comparison of 330 /// two floating point values. The version with a double operand is retained 331 /// because it's so convenient to write isExactlyValue(2.0), but please use 332 /// it only for simple constants. 333 bool isExactlyValue(const APFloat &V) const; 334 isExactlyValue(double V)335 bool isExactlyValue(double V) const { 336 bool ignored; 337 APFloat FV(V); 338 FV.convert(Val.getSemantics(), APFloat::rmNearestTiesToEven, &ignored); 339 return isExactlyValue(FV); 340 } 341 342 /// Methods for support type inquiry through isa, cast, and dyn_cast: classof(const Value * V)343 static bool classof(const Value *V) { 344 return V->getValueID() == ConstantFPVal; 345 } 346 }; 347 348 //===----------------------------------------------------------------------===// 349 /// All zero aggregate value 350 /// 351 class ConstantAggregateZero final : public ConstantData { 352 friend class Constant; 353 ConstantAggregateZero(Type * Ty)354 explicit ConstantAggregateZero(Type *Ty) 355 : ConstantData(Ty, ConstantAggregateZeroVal) {} 356 357 void destroyConstantImpl(); 358 359 public: 360 ConstantAggregateZero(const ConstantAggregateZero &) = delete; 361 362 static ConstantAggregateZero *get(Type *Ty); 363 364 /// If this CAZ has array or vector type, return a zero with the right element 365 /// type. 366 Constant *getSequentialElement() const; 367 368 /// If this CAZ has struct type, return a zero with the right element type for 369 /// the specified element. 370 Constant *getStructElement(unsigned Elt) const; 371 372 /// Return a zero of the right value for the specified GEP index if we can, 373 /// otherwise return null (e.g. if C is a ConstantExpr). 374 Constant *getElementValue(Constant *C) const; 375 376 /// Return a zero of the right value for the specified GEP index. 377 Constant *getElementValue(unsigned Idx) const; 378 379 /// Return the number of elements in the array, vector, or struct. 380 unsigned getNumElements() const; 381 382 /// Methods for support type inquiry through isa, cast, and dyn_cast: 383 /// classof(const Value * V)384 static bool classof(const Value *V) { 385 return V->getValueID() == ConstantAggregateZeroVal; 386 } 387 }; 388 389 /// Base class for aggregate constants (with operands). 390 /// 391 /// These constants are aggregates of other constants, which are stored as 392 /// operands. 393 /// 394 /// Subclasses are \a ConstantStruct, \a ConstantArray, and \a 395 /// ConstantVector. 396 /// 397 /// \note Some subclasses of \a ConstantData are semantically aggregates -- 398 /// such as \a ConstantDataArray -- but are not subclasses of this because they 399 /// use operands. 400 class ConstantAggregate : public Constant { 401 protected: 402 ConstantAggregate(Type *T, ValueTy VT, ArrayRef<Constant *> V); 403 404 public: 405 /// Transparently provide more efficient getOperand methods. 406 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); 407 408 /// Methods for support type inquiry through isa, cast, and dyn_cast: classof(const Value * V)409 static bool classof(const Value *V) { 410 return V->getValueID() >= ConstantAggregateFirstVal && 411 V->getValueID() <= ConstantAggregateLastVal; 412 } 413 }; 414 415 template <> 416 struct OperandTraits<ConstantAggregate> 417 : public VariadicOperandTraits<ConstantAggregate> {}; 418 419 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantAggregate, Constant) 420 421 //===----------------------------------------------------------------------===// 422 /// ConstantArray - Constant Array Declarations 423 /// 424 class ConstantArray final : public ConstantAggregate { 425 friend struct ConstantAggrKeyType<ConstantArray>; 426 friend class Constant; 427 428 ConstantArray(ArrayType *T, ArrayRef<Constant *> Val); 429 430 void destroyConstantImpl(); 431 Value *handleOperandChangeImpl(Value *From, Value *To); 432 433 public: 434 // ConstantArray accessors 435 static Constant *get(ArrayType *T, ArrayRef<Constant*> V); 436 437 private: 438 static Constant *getImpl(ArrayType *T, ArrayRef<Constant *> V); 439 440 public: 441 /// Specialize the getType() method to always return an ArrayType, 442 /// which reduces the amount of casting needed in parts of the compiler. 443 inline ArrayType *getType() const { 444 return cast<ArrayType>(Value::getType()); 445 } 446 447 /// Methods for support type inquiry through isa, cast, and dyn_cast: 448 static bool classof(const Value *V) { 449 return V->getValueID() == ConstantArrayVal; 450 } 451 }; 452 453 //===----------------------------------------------------------------------===// 454 // Constant Struct Declarations 455 // 456 class ConstantStruct final : public ConstantAggregate { 457 friend struct ConstantAggrKeyType<ConstantStruct>; 458 friend class Constant; 459 460 ConstantStruct(StructType *T, ArrayRef<Constant *> Val); 461 462 void destroyConstantImpl(); 463 Value *handleOperandChangeImpl(Value *From, Value *To); 464 465 public: 466 // ConstantStruct accessors 467 static Constant *get(StructType *T, ArrayRef<Constant*> V); 468 469 template <typename... Csts> 470 static std::enable_if_t<are_base_of<Constant, Csts...>::value, Constant *> 471 get(StructType *T, Csts *... Vs) { 472 SmallVector<Constant *, 8> Values({Vs...}); 473 return get(T, Values); 474 } 475 476 /// Return an anonymous struct that has the specified elements. 477 /// If the struct is possibly empty, then you must specify a context. 478 static Constant *getAnon(ArrayRef<Constant*> V, bool Packed = false) { 479 return get(getTypeForElements(V, Packed), V); 480 } 481 static Constant *getAnon(LLVMContext &Ctx, 482 ArrayRef<Constant*> V, bool Packed = false) { 483 return get(getTypeForElements(Ctx, V, Packed), V); 484 } 485 486 /// Return an anonymous struct type to use for a constant with the specified 487 /// set of elements. The list must not be empty. 488 static StructType *getTypeForElements(ArrayRef<Constant*> V, 489 bool Packed = false); 490 /// This version of the method allows an empty list. 491 static StructType *getTypeForElements(LLVMContext &Ctx, 492 ArrayRef<Constant*> V, 493 bool Packed = false); 494 495 /// Specialization - reduce amount of casting. 496 inline StructType *getType() const { 497 return cast<StructType>(Value::getType()); 498 } 499 500 /// Methods for support type inquiry through isa, cast, and dyn_cast: 501 static bool classof(const Value *V) { 502 return V->getValueID() == ConstantStructVal; 503 } 504 }; 505 506 //===----------------------------------------------------------------------===// 507 /// Constant Vector Declarations 508 /// 509 class ConstantVector final : public ConstantAggregate { 510 friend struct ConstantAggrKeyType<ConstantVector>; 511 friend class Constant; 512 513 ConstantVector(VectorType *T, ArrayRef<Constant *> Val); 514 515 void destroyConstantImpl(); 516 Value *handleOperandChangeImpl(Value *From, Value *To); 517 518 public: 519 // ConstantVector accessors 520 static Constant *get(ArrayRef<Constant*> V); 521 522 private: 523 static Constant *getImpl(ArrayRef<Constant *> V); 524 525 public: 526 /// Return a ConstantVector with the specified constant in each element. 527 /// Note that this might not return an instance of ConstantVector 528 static Constant *getSplat(ElementCount EC, Constant *Elt); 529 530 /// Specialize the getType() method to always return a FixedVectorType, 531 /// which reduces the amount of casting needed in parts of the compiler. 532 inline FixedVectorType *getType() const { 533 return cast<FixedVectorType>(Value::getType()); 534 } 535 536 /// If all elements of the vector constant have the same value, return that 537 /// value. Otherwise, return nullptr. Ignore undefined elements by setting 538 /// AllowUndefs to true. 539 Constant *getSplatValue(bool AllowUndefs = false) const; 540 541 /// Methods for support type inquiry through isa, cast, and dyn_cast: 542 static bool classof(const Value *V) { 543 return V->getValueID() == ConstantVectorVal; 544 } 545 }; 546 547 //===----------------------------------------------------------------------===// 548 /// A constant pointer value that points to null 549 /// 550 class ConstantPointerNull final : public ConstantData { 551 friend class Constant; 552 553 explicit ConstantPointerNull(PointerType *T) 554 : ConstantData(T, Value::ConstantPointerNullVal) {} 555 556 void destroyConstantImpl(); 557 558 public: 559 ConstantPointerNull(const ConstantPointerNull &) = delete; 560 561 /// Static factory methods - Return objects of the specified value 562 static ConstantPointerNull *get(PointerType *T); 563 564 /// Specialize the getType() method to always return an PointerType, 565 /// which reduces the amount of casting needed in parts of the compiler. 566 inline PointerType *getType() const { 567 return cast<PointerType>(Value::getType()); 568 } 569 570 /// Methods for support type inquiry through isa, cast, and dyn_cast: 571 static bool classof(const Value *V) { 572 return V->getValueID() == ConstantPointerNullVal; 573 } 574 }; 575 576 //===----------------------------------------------------------------------===// 577 /// ConstantDataSequential - A vector or array constant whose element type is a 578 /// simple 1/2/4/8-byte integer or float/double, and whose elements are just 579 /// simple data values (i.e. ConstantInt/ConstantFP). This Constant node has no 580 /// operands because it stores all of the elements of the constant as densely 581 /// packed data, instead of as Value*'s. 582 /// 583 /// This is the common base class of ConstantDataArray and ConstantDataVector. 584 /// 585 class ConstantDataSequential : public ConstantData { 586 friend class LLVMContextImpl; 587 friend class Constant; 588 589 /// A pointer to the bytes underlying this constant (which is owned by the 590 /// uniquing StringMap). 591 const char *DataElements; 592 593 /// This forms a link list of ConstantDataSequential nodes that have 594 /// the same value but different type. For example, 0,0,0,1 could be a 4 595 /// element array of i8, or a 1-element array of i32. They'll both end up in 596 /// the same StringMap bucket, linked up. 597 std::unique_ptr<ConstantDataSequential> Next; 598 599 void destroyConstantImpl(); 600 601 protected: 602 explicit ConstantDataSequential(Type *ty, ValueTy VT, const char *Data) 603 : ConstantData(ty, VT), DataElements(Data) {} 604 605 static Constant *getImpl(StringRef Bytes, Type *Ty); 606 607 public: 608 ConstantDataSequential(const ConstantDataSequential &) = delete; 609 610 /// Return true if a ConstantDataSequential can be formed with a vector or 611 /// array of the specified element type. 612 /// ConstantDataArray only works with normal float and int types that are 613 /// stored densely in memory, not with things like i42 or x86_f80. 614 static bool isElementTypeCompatible(Type *Ty); 615 616 /// If this is a sequential container of integers (of any size), return the 617 /// specified element in the low bits of a uint64_t. 618 uint64_t getElementAsInteger(unsigned i) const; 619 620 /// If this is a sequential container of integers (of any size), return the 621 /// specified element as an APInt. 622 APInt getElementAsAPInt(unsigned i) const; 623 624 /// If this is a sequential container of floating point type, return the 625 /// specified element as an APFloat. 626 APFloat getElementAsAPFloat(unsigned i) const; 627 628 /// If this is an sequential container of floats, return the specified element 629 /// as a float. 630 float getElementAsFloat(unsigned i) const; 631 632 /// If this is an sequential container of doubles, return the specified 633 /// element as a double. 634 double getElementAsDouble(unsigned i) const; 635 636 /// Return a Constant for a specified index's element. 637 /// Note that this has to compute a new constant to return, so it isn't as 638 /// efficient as getElementAsInteger/Float/Double. 639 Constant *getElementAsConstant(unsigned i) const; 640 641 /// Return the element type of the array/vector. 642 Type *getElementType() const; 643 644 /// Return the number of elements in the array or vector. 645 unsigned getNumElements() const; 646 647 /// Return the size (in bytes) of each element in the array/vector. 648 /// The size of the elements is known to be a multiple of one byte. 649 uint64_t getElementByteSize() const; 650 651 /// This method returns true if this is an array of \p CharSize integers. 652 bool isString(unsigned CharSize = 8) const; 653 654 /// This method returns true if the array "isString", ends with a null byte, 655 /// and does not contains any other null bytes. 656 bool isCString() const; 657 658 /// If this array is isString(), then this method returns the array as a 659 /// StringRef. Otherwise, it asserts out. 660 StringRef getAsString() const { 661 assert(isString() && "Not a string"); 662 return getRawDataValues(); 663 } 664 665 /// If this array is isCString(), then this method returns the array (without 666 /// the trailing null byte) as a StringRef. Otherwise, it asserts out. 667 StringRef getAsCString() const { 668 assert(isCString() && "Isn't a C string"); 669 StringRef Str = getAsString(); 670 return Str.substr(0, Str.size()-1); 671 } 672 673 /// Return the raw, underlying, bytes of this data. Note that this is an 674 /// extremely tricky thing to work with, as it exposes the host endianness of 675 /// the data elements. 676 StringRef getRawDataValues() const; 677 678 /// Methods for support type inquiry through isa, cast, and dyn_cast: 679 static bool classof(const Value *V) { 680 return V->getValueID() == ConstantDataArrayVal || 681 V->getValueID() == ConstantDataVectorVal; 682 } 683 684 private: 685 const char *getElementPointer(unsigned Elt) const; 686 }; 687 688 //===----------------------------------------------------------------------===// 689 /// An array constant whose element type is a simple 1/2/4/8-byte integer or 690 /// float/double, and whose elements are just simple data values 691 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it 692 /// stores all of the elements of the constant as densely packed data, instead 693 /// of as Value*'s. 694 class ConstantDataArray final : public ConstantDataSequential { 695 friend class ConstantDataSequential; 696 697 explicit ConstantDataArray(Type *ty, const char *Data) 698 : ConstantDataSequential(ty, ConstantDataArrayVal, Data) {} 699 700 public: 701 ConstantDataArray(const ConstantDataArray &) = delete; 702 703 /// get() constructor - Return a constant with array type with an element 704 /// count and element type matching the ArrayRef passed in. Note that this 705 /// can return a ConstantAggregateZero object. 706 template <typename ElementTy> 707 static Constant *get(LLVMContext &Context, ArrayRef<ElementTy> Elts) { 708 const char *Data = reinterpret_cast<const char *>(Elts.data()); 709 return getRaw(StringRef(Data, Elts.size() * sizeof(ElementTy)), Elts.size(), 710 Type::getScalarTy<ElementTy>(Context)); 711 } 712 713 /// get() constructor - ArrayTy needs to be compatible with 714 /// ArrayRef<ElementTy>. Calls get(LLVMContext, ArrayRef<ElementTy>). 715 template <typename ArrayTy> 716 static Constant *get(LLVMContext &Context, ArrayTy &Elts) { 717 return ConstantDataArray::get(Context, makeArrayRef(Elts)); 718 } 719 720 /// get() constructor - Return a constant with array type with an element 721 /// count and element type matching the NumElements and ElementTy parameters 722 /// passed in. Note that this can return a ConstantAggregateZero object. 723 /// ElementTy needs to be one of i8/i16/i32/i64/float/double. Data is the 724 /// buffer containing the elements. Be careful to make sure Data uses the 725 /// right endianness, the buffer will be used as-is. 726 static Constant *getRaw(StringRef Data, uint64_t NumElements, Type *ElementTy) { 727 Type *Ty = ArrayType::get(ElementTy, NumElements); 728 return getImpl(Data, Ty); 729 } 730 731 /// getFP() constructors - Return a constant of array type with a float 732 /// element type taken from argument `ElementType', and count taken from 733 /// argument `Elts'. The amount of bits of the contained type must match the 734 /// number of bits of the type contained in the passed in ArrayRef. 735 /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note 736 /// that this can return a ConstantAggregateZero object. 737 static Constant *getFP(Type *ElementType, ArrayRef<uint16_t> Elts); 738 static Constant *getFP(Type *ElementType, ArrayRef<uint32_t> Elts); 739 static Constant *getFP(Type *ElementType, ArrayRef<uint64_t> Elts); 740 741 /// This method constructs a CDS and initializes it with a text string. 742 /// The default behavior (AddNull==true) causes a null terminator to 743 /// be placed at the end of the array (increasing the length of the string by 744 /// one more than the StringRef would normally indicate. Pass AddNull=false 745 /// to disable this behavior. 746 static Constant *getString(LLVMContext &Context, StringRef Initializer, 747 bool AddNull = true); 748 749 /// Specialize the getType() method to always return an ArrayType, 750 /// which reduces the amount of casting needed in parts of the compiler. 751 inline ArrayType *getType() const { 752 return cast<ArrayType>(Value::getType()); 753 } 754 755 /// Methods for support type inquiry through isa, cast, and dyn_cast: 756 static bool classof(const Value *V) { 757 return V->getValueID() == ConstantDataArrayVal; 758 } 759 }; 760 761 //===----------------------------------------------------------------------===// 762 /// A vector constant whose element type is a simple 1/2/4/8-byte integer or 763 /// float/double, and whose elements are just simple data values 764 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it 765 /// stores all of the elements of the constant as densely packed data, instead 766 /// of as Value*'s. 767 class ConstantDataVector final : public ConstantDataSequential { 768 friend class ConstantDataSequential; 769 770 explicit ConstantDataVector(Type *ty, const char *Data) 771 : ConstantDataSequential(ty, ConstantDataVectorVal, Data), 772 IsSplatSet(false) {} 773 // Cache whether or not the constant is a splat. 774 mutable bool IsSplatSet : 1; 775 mutable bool IsSplat : 1; 776 bool isSplatData() const; 777 778 public: 779 ConstantDataVector(const ConstantDataVector &) = delete; 780 781 /// get() constructors - Return a constant with vector type with an element 782 /// count and element type matching the ArrayRef passed in. Note that this 783 /// can return a ConstantAggregateZero object. 784 static Constant *get(LLVMContext &Context, ArrayRef<uint8_t> Elts); 785 static Constant *get(LLVMContext &Context, ArrayRef<uint16_t> Elts); 786 static Constant *get(LLVMContext &Context, ArrayRef<uint32_t> Elts); 787 static Constant *get(LLVMContext &Context, ArrayRef<uint64_t> Elts); 788 static Constant *get(LLVMContext &Context, ArrayRef<float> Elts); 789 static Constant *get(LLVMContext &Context, ArrayRef<double> Elts); 790 791 /// getFP() constructors - Return a constant of vector type with a float 792 /// element type taken from argument `ElementType', and count taken from 793 /// argument `Elts'. The amount of bits of the contained type must match the 794 /// number of bits of the type contained in the passed in ArrayRef. 795 /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note 796 /// that this can return a ConstantAggregateZero object. 797 static Constant *getFP(Type *ElementType, ArrayRef<uint16_t> Elts); 798 static Constant *getFP(Type *ElementType, ArrayRef<uint32_t> Elts); 799 static Constant *getFP(Type *ElementType, ArrayRef<uint64_t> Elts); 800 801 /// Return a ConstantVector with the specified constant in each element. 802 /// The specified constant has to be a of a compatible type (i8/i16/ 803 /// i32/i64/float/double) and must be a ConstantFP or ConstantInt. 804 static Constant *getSplat(unsigned NumElts, Constant *Elt); 805 806 /// Returns true if this is a splat constant, meaning that all elements have 807 /// the same value. 808 bool isSplat() const; 809 810 /// If this is a splat constant, meaning that all of the elements have the 811 /// same value, return that value. Otherwise return NULL. 812 Constant *getSplatValue() const; 813 814 /// Specialize the getType() method to always return a FixedVectorType, 815 /// which reduces the amount of casting needed in parts of the compiler. 816 inline FixedVectorType *getType() const { 817 return cast<FixedVectorType>(Value::getType()); 818 } 819 820 /// Methods for support type inquiry through isa, cast, and dyn_cast: 821 static bool classof(const Value *V) { 822 return V->getValueID() == ConstantDataVectorVal; 823 } 824 }; 825 826 //===----------------------------------------------------------------------===// 827 /// A constant token which is empty 828 /// 829 class ConstantTokenNone final : public ConstantData { 830 friend class Constant; 831 832 explicit ConstantTokenNone(LLVMContext &Context) 833 : ConstantData(Type::getTokenTy(Context), ConstantTokenNoneVal) {} 834 835 void destroyConstantImpl(); 836 837 public: 838 ConstantTokenNone(const ConstantTokenNone &) = delete; 839 840 /// Return the ConstantTokenNone. 841 static ConstantTokenNone *get(LLVMContext &Context); 842 843 /// Methods to support type inquiry through isa, cast, and dyn_cast. 844 static bool classof(const Value *V) { 845 return V->getValueID() == ConstantTokenNoneVal; 846 } 847 }; 848 849 /// The address of a basic block. 850 /// 851 class BlockAddress final : public Constant { 852 friend class Constant; 853 854 BlockAddress(Function *F, BasicBlock *BB); 855 856 void *operator new(size_t s) { return User::operator new(s, 2); } 857 858 void destroyConstantImpl(); 859 Value *handleOperandChangeImpl(Value *From, Value *To); 860 861 public: 862 /// Return a BlockAddress for the specified function and basic block. 863 static BlockAddress *get(Function *F, BasicBlock *BB); 864 865 /// Return a BlockAddress for the specified basic block. The basic 866 /// block must be embedded into a function. 867 static BlockAddress *get(BasicBlock *BB); 868 869 /// Lookup an existing \c BlockAddress constant for the given BasicBlock. 870 /// 871 /// \returns 0 if \c !BB->hasAddressTaken(), otherwise the \c BlockAddress. 872 static BlockAddress *lookup(const BasicBlock *BB); 873 874 /// Transparently provide more efficient getOperand methods. 875 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value); 876 877 Function *getFunction() const { return (Function*)Op<0>().get(); } 878 BasicBlock *getBasicBlock() const { return (BasicBlock*)Op<1>().get(); } 879 880 /// Methods for support type inquiry through isa, cast, and dyn_cast: 881 static bool classof(const Value *V) { 882 return V->getValueID() == BlockAddressVal; 883 } 884 }; 885 886 template <> 887 struct OperandTraits<BlockAddress> : 888 public FixedNumOperandTraits<BlockAddress, 2> { 889 }; 890 891 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BlockAddress, Value) 892 893 /// Wrapper for a function that represents a value that 894 /// functionally represents the original function. This can be a function, 895 /// global alias to a function, or an ifunc. 896 class DSOLocalEquivalent final : public Constant { 897 friend class Constant; 898 899 DSOLocalEquivalent(GlobalValue *GV); 900 901 void *operator new(size_t s) { return User::operator new(s, 1); } 902 903 void destroyConstantImpl(); 904 Value *handleOperandChangeImpl(Value *From, Value *To); 905 906 public: 907 /// Return a DSOLocalEquivalent for the specified global value. 908 static DSOLocalEquivalent *get(GlobalValue *GV); 909 910 /// Transparently provide more efficient getOperand methods. 911 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value); 912 913 GlobalValue *getGlobalValue() const { 914 return cast<GlobalValue>(Op<0>().get()); 915 } 916 917 /// Methods for support type inquiry through isa, cast, and dyn_cast: 918 static bool classof(const Value *V) { 919 return V->getValueID() == DSOLocalEquivalentVal; 920 } 921 }; 922 923 template <> 924 struct OperandTraits<DSOLocalEquivalent> 925 : public FixedNumOperandTraits<DSOLocalEquivalent, 1> {}; 926 927 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(DSOLocalEquivalent, Value) 928 929 //===----------------------------------------------------------------------===// 930 /// A constant value that is initialized with an expression using 931 /// other constant values. 932 /// 933 /// This class uses the standard Instruction opcodes to define the various 934 /// constant expressions. The Opcode field for the ConstantExpr class is 935 /// maintained in the Value::SubclassData field. 936 class ConstantExpr : public Constant { 937 friend struct ConstantExprKeyType; 938 friend class Constant; 939 940 void destroyConstantImpl(); 941 Value *handleOperandChangeImpl(Value *From, Value *To); 942 943 protected: 944 ConstantExpr(Type *ty, unsigned Opcode, Use *Ops, unsigned NumOps) 945 : Constant(ty, ConstantExprVal, Ops, NumOps) { 946 // Operation type (an Instruction opcode) is stored as the SubclassData. 947 setValueSubclassData(Opcode); 948 } 949 950 ~ConstantExpr() = default; 951 952 public: 953 // Static methods to construct a ConstantExpr of different kinds. Note that 954 // these methods may return a object that is not an instance of the 955 // ConstantExpr class, because they will attempt to fold the constant 956 // expression into something simpler if possible. 957 958 /// getAlignOf constant expr - computes the alignment of a type in a target 959 /// independent way (Note: the return type is an i64). 960 static Constant *getAlignOf(Type *Ty); 961 962 /// getSizeOf constant expr - computes the (alloc) size of a type (in 963 /// address-units, not bits) in a target independent way (Note: the return 964 /// type is an i64). 965 /// 966 static Constant *getSizeOf(Type *Ty); 967 968 /// getOffsetOf constant expr - computes the offset of a struct field in a 969 /// target independent way (Note: the return type is an i64). 970 /// 971 static Constant *getOffsetOf(StructType *STy, unsigned FieldNo); 972 973 /// getOffsetOf constant expr - This is a generalized form of getOffsetOf, 974 /// which supports any aggregate type, and any Constant index. 975 /// 976 static Constant *getOffsetOf(Type *Ty, Constant *FieldNo); 977 978 static Constant *getNeg(Constant *C, bool HasNUW = false, bool HasNSW =false); 979 static Constant *getFNeg(Constant *C); 980 static Constant *getNot(Constant *C); 981 static Constant *getAdd(Constant *C1, Constant *C2, 982 bool HasNUW = false, bool HasNSW = false); 983 static Constant *getFAdd(Constant *C1, Constant *C2); 984 static Constant *getSub(Constant *C1, Constant *C2, 985 bool HasNUW = false, bool HasNSW = false); 986 static Constant *getFSub(Constant *C1, Constant *C2); 987 static Constant *getMul(Constant *C1, Constant *C2, 988 bool HasNUW = false, bool HasNSW = false); 989 static Constant *getFMul(Constant *C1, Constant *C2); 990 static Constant *getUDiv(Constant *C1, Constant *C2, bool isExact = false); 991 static Constant *getSDiv(Constant *C1, Constant *C2, bool isExact = false); 992 static Constant *getFDiv(Constant *C1, Constant *C2); 993 static Constant *getURem(Constant *C1, Constant *C2); 994 static Constant *getSRem(Constant *C1, Constant *C2); 995 static Constant *getFRem(Constant *C1, Constant *C2); 996 static Constant *getAnd(Constant *C1, Constant *C2); 997 static Constant *getOr(Constant *C1, Constant *C2); 998 static Constant *getXor(Constant *C1, Constant *C2); 999 static Constant *getUMin(Constant *C1, Constant *C2); 1000 static Constant *getShl(Constant *C1, Constant *C2, 1001 bool HasNUW = false, bool HasNSW = false); 1002 static Constant *getLShr(Constant *C1, Constant *C2, bool isExact = false); 1003 static Constant *getAShr(Constant *C1, Constant *C2, bool isExact = false); 1004 static Constant *getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1005 static Constant *getSExt(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1006 static Constant *getZExt(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1007 static Constant *getFPTrunc(Constant *C, Type *Ty, 1008 bool OnlyIfReduced = false); 1009 static Constant *getFPExtend(Constant *C, Type *Ty, 1010 bool OnlyIfReduced = false); 1011 static Constant *getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1012 static Constant *getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1013 static Constant *getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1014 static Constant *getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced = false); 1015 static Constant *getPtrToInt(Constant *C, Type *Ty, 1016 bool OnlyIfReduced = false); 1017 static Constant *getIntToPtr(Constant *C, Type *Ty, 1018 bool OnlyIfReduced = false); 1019 static Constant *getBitCast(Constant *C, Type *Ty, 1020 bool OnlyIfReduced = false); 1021 static Constant *getAddrSpaceCast(Constant *C, Type *Ty, 1022 bool OnlyIfReduced = false); 1023 1024 static Constant *getNSWNeg(Constant *C) { return getNeg(C, false, true); } 1025 static Constant *getNUWNeg(Constant *C) { return getNeg(C, true, false); } 1026 1027 static Constant *getNSWAdd(Constant *C1, Constant *C2) { 1028 return getAdd(C1, C2, false, true); 1029 } 1030 1031 static Constant *getNUWAdd(Constant *C1, Constant *C2) { 1032 return getAdd(C1, C2, true, false); 1033 } 1034 1035 static Constant *getNSWSub(Constant *C1, Constant *C2) { 1036 return getSub(C1, C2, false, true); 1037 } 1038 1039 static Constant *getNUWSub(Constant *C1, Constant *C2) { 1040 return getSub(C1, C2, true, false); 1041 } 1042 1043 static Constant *getNSWMul(Constant *C1, Constant *C2) { 1044 return getMul(C1, C2, false, true); 1045 } 1046 1047 static Constant *getNUWMul(Constant *C1, Constant *C2) { 1048 return getMul(C1, C2, true, false); 1049 } 1050 1051 static Constant *getNSWShl(Constant *C1, Constant *C2) { 1052 return getShl(C1, C2, false, true); 1053 } 1054 1055 static Constant *getNUWShl(Constant *C1, Constant *C2) { 1056 return getShl(C1, C2, true, false); 1057 } 1058 1059 static Constant *getExactSDiv(Constant *C1, Constant *C2) { 1060 return getSDiv(C1, C2, true); 1061 } 1062 1063 static Constant *getExactUDiv(Constant *C1, Constant *C2) { 1064 return getUDiv(C1, C2, true); 1065 } 1066 1067 static Constant *getExactAShr(Constant *C1, Constant *C2) { 1068 return getAShr(C1, C2, true); 1069 } 1070 1071 static Constant *getExactLShr(Constant *C1, Constant *C2) { 1072 return getLShr(C1, C2, true); 1073 } 1074 1075 /// If C is a scalar/fixed width vector of known powers of 2, then this 1076 /// function returns a new scalar/fixed width vector obtained from logBase2 1077 /// of C. Undef vector elements are set to zero. 1078 /// Return a null pointer otherwise. 1079 static Constant *getExactLogBase2(Constant *C); 1080 1081 /// Return the identity constant for a binary opcode. 1082 /// The identity constant C is defined as X op C = X and C op X = X for every 1083 /// X when the binary operation is commutative. If the binop is not 1084 /// commutative, callers can acquire the operand 1 identity constant by 1085 /// setting AllowRHSConstant to true. For example, any shift has a zero 1086 /// identity constant for operand 1: X shift 0 = X. 1087 /// Return nullptr if the operator does not have an identity constant. 1088 static Constant *getBinOpIdentity(unsigned Opcode, Type *Ty, 1089 bool AllowRHSConstant = false); 1090 1091 /// Return the absorbing element for the given binary 1092 /// operation, i.e. a constant C such that X op C = C and C op X = C for 1093 /// every X. For example, this returns zero for integer multiplication. 1094 /// It returns null if the operator doesn't have an absorbing element. 1095 static Constant *getBinOpAbsorber(unsigned Opcode, Type *Ty); 1096 1097 /// Transparently provide more efficient getOperand methods. 1098 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); 1099 1100 /// Convenience function for getting a Cast operation. 1101 /// 1102 /// \param ops The opcode for the conversion 1103 /// \param C The constant to be converted 1104 /// \param Ty The type to which the constant is converted 1105 /// \param OnlyIfReduced see \a getWithOperands() docs. 1106 static Constant *getCast(unsigned ops, Constant *C, Type *Ty, 1107 bool OnlyIfReduced = false); 1108 1109 // Create a ZExt or BitCast cast constant expression 1110 static Constant *getZExtOrBitCast( 1111 Constant *C, ///< The constant to zext or bitcast 1112 Type *Ty ///< The type to zext or bitcast C to 1113 ); 1114 1115 // Create a SExt or BitCast cast constant expression 1116 static Constant *getSExtOrBitCast( 1117 Constant *C, ///< The constant to sext or bitcast 1118 Type *Ty ///< The type to sext or bitcast C to 1119 ); 1120 1121 // Create a Trunc or BitCast cast constant expression 1122 static Constant *getTruncOrBitCast( 1123 Constant *C, ///< The constant to trunc or bitcast 1124 Type *Ty ///< The type to trunc or bitcast C to 1125 ); 1126 1127 /// Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant 1128 /// expression. 1129 static Constant *getPointerCast( 1130 Constant *C, ///< The pointer value to be casted (operand 0) 1131 Type *Ty ///< The type to which cast should be made 1132 ); 1133 1134 /// Create a BitCast or AddrSpaceCast for a pointer type depending on 1135 /// the address space. 1136 static Constant *getPointerBitCastOrAddrSpaceCast( 1137 Constant *C, ///< The constant to addrspacecast or bitcast 1138 Type *Ty ///< The type to bitcast or addrspacecast C to 1139 ); 1140 1141 /// Create a ZExt, Bitcast or Trunc for integer -> integer casts 1142 static Constant *getIntegerCast( 1143 Constant *C, ///< The integer constant to be casted 1144 Type *Ty, ///< The integer type to cast to 1145 bool isSigned ///< Whether C should be treated as signed or not 1146 ); 1147 1148 /// Create a FPExt, Bitcast or FPTrunc for fp -> fp casts 1149 static Constant *getFPCast( 1150 Constant *C, ///< The integer constant to be casted 1151 Type *Ty ///< The integer type to cast to 1152 ); 1153 1154 /// Return true if this is a convert constant expression 1155 bool isCast() const; 1156 1157 /// Return true if this is a compare constant expression 1158 bool isCompare() const; 1159 1160 /// Return true if this is an insertvalue or extractvalue expression, 1161 /// and the getIndices() method may be used. 1162 bool hasIndices() const; 1163 1164 /// Return true if this is a getelementptr expression and all 1165 /// the index operands are compile-time known integers within the 1166 /// corresponding notional static array extents. Note that this is 1167 /// not equivalant to, a subset of, or a superset of the "inbounds" 1168 /// property. 1169 bool isGEPWithNoNotionalOverIndexing() const; 1170 1171 /// Select constant expr 1172 /// 1173 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1174 static Constant *getSelect(Constant *C, Constant *V1, Constant *V2, 1175 Type *OnlyIfReducedTy = nullptr); 1176 1177 /// get - Return a unary operator constant expression, 1178 /// folding if possible. 1179 /// 1180 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1181 static Constant *get(unsigned Opcode, Constant *C1, unsigned Flags = 0, 1182 Type *OnlyIfReducedTy = nullptr); 1183 1184 /// get - Return a binary or shift operator constant expression, 1185 /// folding if possible. 1186 /// 1187 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1188 static Constant *get(unsigned Opcode, Constant *C1, Constant *C2, 1189 unsigned Flags = 0, Type *OnlyIfReducedTy = nullptr); 1190 1191 /// Return an ICmp or FCmp comparison operator constant expression. 1192 /// 1193 /// \param OnlyIfReduced see \a getWithOperands() docs. 1194 static Constant *getCompare(unsigned short pred, Constant *C1, Constant *C2, 1195 bool OnlyIfReduced = false); 1196 1197 /// get* - Return some common constants without having to 1198 /// specify the full Instruction::OPCODE identifier. 1199 /// 1200 static Constant *getICmp(unsigned short pred, Constant *LHS, Constant *RHS, 1201 bool OnlyIfReduced = false); 1202 static Constant *getFCmp(unsigned short pred, Constant *LHS, Constant *RHS, 1203 bool OnlyIfReduced = false); 1204 1205 /// Getelementptr form. Value* is only accepted for convenience; 1206 /// all elements must be Constants. 1207 /// 1208 /// \param InRangeIndex the inrange index if present or None. 1209 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1210 static Constant *getGetElementPtr(Type *Ty, Constant *C, 1211 ArrayRef<Constant *> IdxList, 1212 bool InBounds = false, 1213 Optional<unsigned> InRangeIndex = None, 1214 Type *OnlyIfReducedTy = nullptr) { 1215 return getGetElementPtr( 1216 Ty, C, makeArrayRef((Value * const *)IdxList.data(), IdxList.size()), 1217 InBounds, InRangeIndex, OnlyIfReducedTy); 1218 } 1219 static Constant *getGetElementPtr(Type *Ty, Constant *C, Constant *Idx, 1220 bool InBounds = false, 1221 Optional<unsigned> InRangeIndex = None, 1222 Type *OnlyIfReducedTy = nullptr) { 1223 // This form of the function only exists to avoid ambiguous overload 1224 // warnings about whether to convert Idx to ArrayRef<Constant *> or 1225 // ArrayRef<Value *>. 1226 return getGetElementPtr(Ty, C, cast<Value>(Idx), InBounds, InRangeIndex, 1227 OnlyIfReducedTy); 1228 } 1229 static Constant *getGetElementPtr(Type *Ty, Constant *C, 1230 ArrayRef<Value *> IdxList, 1231 bool InBounds = false, 1232 Optional<unsigned> InRangeIndex = None, 1233 Type *OnlyIfReducedTy = nullptr); 1234 1235 /// Create an "inbounds" getelementptr. See the documentation for the 1236 /// "inbounds" flag in LangRef.html for details. 1237 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1238 ArrayRef<Constant *> IdxList) { 1239 return getGetElementPtr(Ty, C, IdxList, true); 1240 } 1241 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1242 Constant *Idx) { 1243 // This form of the function only exists to avoid ambiguous overload 1244 // warnings about whether to convert Idx to ArrayRef<Constant *> or 1245 // ArrayRef<Value *>. 1246 return getGetElementPtr(Ty, C, Idx, true); 1247 } 1248 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1249 ArrayRef<Value *> IdxList) { 1250 return getGetElementPtr(Ty, C, IdxList, true); 1251 } 1252 1253 static Constant *getExtractElement(Constant *Vec, Constant *Idx, 1254 Type *OnlyIfReducedTy = nullptr); 1255 static Constant *getInsertElement(Constant *Vec, Constant *Elt, Constant *Idx, 1256 Type *OnlyIfReducedTy = nullptr); 1257 static Constant *getShuffleVector(Constant *V1, Constant *V2, 1258 ArrayRef<int> Mask, 1259 Type *OnlyIfReducedTy = nullptr); 1260 static Constant *getExtractValue(Constant *Agg, ArrayRef<unsigned> Idxs, 1261 Type *OnlyIfReducedTy = nullptr); 1262 static Constant *getInsertValue(Constant *Agg, Constant *Val, 1263 ArrayRef<unsigned> Idxs, 1264 Type *OnlyIfReducedTy = nullptr); 1265 1266 /// Return the opcode at the root of this constant expression 1267 unsigned getOpcode() const { return getSubclassDataFromValue(); } 1268 1269 /// Return the ICMP or FCMP predicate value. Assert if this is not an ICMP or 1270 /// FCMP constant expression. 1271 unsigned getPredicate() const; 1272 1273 /// Assert that this is an insertvalue or exactvalue 1274 /// expression and return the list of indices. 1275 ArrayRef<unsigned> getIndices() const; 1276 1277 /// Assert that this is a shufflevector and return the mask. See class 1278 /// ShuffleVectorInst for a description of the mask representation. 1279 ArrayRef<int> getShuffleMask() const; 1280 1281 /// Assert that this is a shufflevector and return the mask. 1282 /// 1283 /// TODO: This is a temporary hack until we update the bitcode format for 1284 /// shufflevector. 1285 Constant *getShuffleMaskForBitcode() const; 1286 1287 /// Return a string representation for an opcode. 1288 const char *getOpcodeName() const; 1289 1290 /// Return a constant expression identical to this one, but with the specified 1291 /// operand set to the specified value. 1292 Constant *getWithOperandReplaced(unsigned OpNo, Constant *Op) const; 1293 1294 /// This returns the current constant expression with the operands replaced 1295 /// with the specified values. The specified array must have the same number 1296 /// of operands as our current one. 1297 Constant *getWithOperands(ArrayRef<Constant*> Ops) const { 1298 return getWithOperands(Ops, getType()); 1299 } 1300 1301 /// Get the current expression with the operands replaced. 1302 /// 1303 /// Return the current constant expression with the operands replaced with \c 1304 /// Ops and the type with \c Ty. The new operands must have the same number 1305 /// as the current ones. 1306 /// 1307 /// If \c OnlyIfReduced is \c true, nullptr will be returned unless something 1308 /// gets constant-folded, the type changes, or the expression is otherwise 1309 /// canonicalized. This parameter should almost always be \c false. 1310 Constant *getWithOperands(ArrayRef<Constant *> Ops, Type *Ty, 1311 bool OnlyIfReduced = false, 1312 Type *SrcTy = nullptr) const; 1313 1314 /// Returns an Instruction which implements the same operation as this 1315 /// ConstantExpr. The instruction is not linked to any basic block. 1316 /// 1317 /// A better approach to this could be to have a constructor for Instruction 1318 /// which would take a ConstantExpr parameter, but that would have spread 1319 /// implementation details of ConstantExpr outside of Constants.cpp, which 1320 /// would make it harder to remove ConstantExprs altogether. 1321 Instruction *getAsInstruction() const; 1322 1323 /// Methods for support type inquiry through isa, cast, and dyn_cast: 1324 static bool classof(const Value *V) { 1325 return V->getValueID() == ConstantExprVal; 1326 } 1327 1328 private: 1329 // Shadow Value::setValueSubclassData with a private forwarding method so that 1330 // subclasses cannot accidentally use it. 1331 void setValueSubclassData(unsigned short D) { 1332 Value::setValueSubclassData(D); 1333 } 1334 }; 1335 1336 template <> 1337 struct OperandTraits<ConstantExpr> : 1338 public VariadicOperandTraits<ConstantExpr, 1> { 1339 }; 1340 1341 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantExpr, Constant) 1342 1343 //===----------------------------------------------------------------------===// 1344 /// 'undef' values are things that do not have specified contents. 1345 /// These are used for a variety of purposes, including global variable 1346 /// initializers and operands to instructions. 'undef' values can occur with 1347 /// any first-class type. 1348 /// 1349 /// Undef values aren't exactly constants; if they have multiple uses, they 1350 /// can appear to have different bit patterns at each use. See 1351 /// LangRef.html#undefvalues for details. 1352 /// 1353 class UndefValue : public ConstantData { 1354 friend class Constant; 1355 1356 explicit UndefValue(Type *T) : ConstantData(T, UndefValueVal) {} 1357 1358 void destroyConstantImpl(); 1359 1360 protected: 1361 explicit UndefValue(Type *T, ValueTy vty) : ConstantData(T, vty) {} 1362 1363 public: 1364 UndefValue(const UndefValue &) = delete; 1365 1366 /// Static factory methods - Return an 'undef' object of the specified type. 1367 static UndefValue *get(Type *T); 1368 1369 /// If this Undef has array or vector type, return a undef with the right 1370 /// element type. 1371 UndefValue *getSequentialElement() const; 1372 1373 /// If this undef has struct type, return a undef with the right element type 1374 /// for the specified element. 1375 UndefValue *getStructElement(unsigned Elt) const; 1376 1377 /// Return an undef of the right value for the specified GEP index if we can, 1378 /// otherwise return null (e.g. if C is a ConstantExpr). 1379 UndefValue *getElementValue(Constant *C) const; 1380 1381 /// Return an undef of the right value for the specified GEP index. 1382 UndefValue *getElementValue(unsigned Idx) const; 1383 1384 /// Return the number of elements in the array, vector, or struct. 1385 unsigned getNumElements() const; 1386 1387 /// Methods for support type inquiry through isa, cast, and dyn_cast: 1388 static bool classof(const Value *V) { 1389 return V->getValueID() == UndefValueVal || 1390 V->getValueID() == PoisonValueVal; 1391 } 1392 }; 1393 1394 //===----------------------------------------------------------------------===// 1395 /// In order to facilitate speculative execution, many instructions do not 1396 /// invoke immediate undefined behavior when provided with illegal operands, 1397 /// and return a poison value instead. 1398 /// 1399 /// see LangRef.html#poisonvalues for details. 1400 /// 1401 class PoisonValue final : public UndefValue { 1402 friend class Constant; 1403 1404 explicit PoisonValue(Type *T) : UndefValue(T, PoisonValueVal) {} 1405 1406 void destroyConstantImpl(); 1407 1408 public: 1409 PoisonValue(const PoisonValue &) = delete; 1410 1411 /// Static factory methods - Return an 'poison' object of the specified type. 1412 static PoisonValue *get(Type *T); 1413 1414 /// If this poison has array or vector type, return a poison with the right 1415 /// element type. 1416 PoisonValue *getSequentialElement() const; 1417 1418 /// If this poison has struct type, return a poison with the right element 1419 /// type for the specified element. 1420 PoisonValue *getStructElement(unsigned Elt) const; 1421 1422 /// Return an poison of the right value for the specified GEP index if we can, 1423 /// otherwise return null (e.g. if C is a ConstantExpr). 1424 PoisonValue *getElementValue(Constant *C) const; 1425 1426 /// Return an poison of the right value for the specified GEP index. 1427 PoisonValue *getElementValue(unsigned Idx) const; 1428 1429 /// Methods for support type inquiry through isa, cast, and dyn_cast: 1430 static bool classof(const Value *V) { 1431 return V->getValueID() == PoisonValueVal; 1432 } 1433 }; 1434 1435 } // end namespace llvm 1436 1437 #endif // LLVM_IR_CONSTANTS_H 1438