1 //===-- llvm/Constants.h - Constant class subclass definitions --*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 /// @file 11 /// This file contains the declarations for the subclasses of Constant, 12 /// which represent the different flavors of constant values that live in LLVM. 13 /// Note that Constants are immutable (once created they never change) and are 14 /// fully shared by structural equivalence. This means that two structurally 15 /// equivalent constants will always have the same address. Constants are 16 /// created on demand as needed and never deleted: thus clients don't have to 17 /// worry about the lifetime of the objects. 18 // 19 //===----------------------------------------------------------------------===// 20 21 #ifndef LLVM_IR_CONSTANTS_H 22 #define LLVM_IR_CONSTANTS_H 23 24 #include "llvm/ADT/APFloat.h" 25 #include "llvm/ADT/APInt.h" 26 #include "llvm/ADT/ArrayRef.h" 27 #include "llvm/ADT/None.h" 28 #include "llvm/ADT/Optional.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 class ArrayType; 45 class IntegerType; 46 class PointerType; 47 class SequentialType; 48 class StructType; 49 class VectorType; 50 template <class ConstantClass> struct ConstantAggrKeyType; 51 52 /// Base class for constants with no operands. 53 /// 54 /// These constants have no operands; they represent their data directly. 55 /// Since they can be in use by unrelated modules (and are never based on 56 /// GlobalValues), it never makes sense to RAUW them. 57 class ConstantData : public Constant { 58 friend class Constant; 59 60 void anchor() override; 61 62 Value *handleOperandChangeImpl(Value *From, Value *To) { 63 llvm_unreachable("Constant data does not have operands!"); 64 } 65 66 protected: 67 explicit ConstantData(Type *Ty, ValueTy VT) : Constant(Ty, VT, nullptr, 0) {} 68 69 void *operator new(size_t s) { return User::operator new(s, 0); } 70 71 public: 72 ConstantData() = delete; 73 ConstantData(const ConstantData &) = delete; 74 75 void *operator new(size_t, unsigned) = delete; 76 77 /// Methods to support type inquiry through isa, cast, and dyn_cast. 78 static bool classof(const Value *V) { 79 return V->getValueID() >= ConstantDataFirstVal && 80 V->getValueID() <= ConstantDataLastVal; 81 } 82 }; 83 84 //===----------------------------------------------------------------------===// 85 /// This is the shared class of boolean and integer constants. This class 86 /// represents both boolean and integral constants. 87 /// @brief Class for constant integers. 88 class ConstantInt final : public ConstantData { 89 friend class Constant; 90 91 APInt Val; 92 93 ConstantInt(IntegerType *Ty, const APInt& V); 94 95 void anchor() override; 96 void destroyConstantImpl(); 97 98 public: 99 ConstantInt(const ConstantInt &) = delete; 100 101 static ConstantInt *getTrue(LLVMContext &Context); 102 static ConstantInt *getFalse(LLVMContext &Context); 103 static Constant *getTrue(Type *Ty); 104 static Constant *getFalse(Type *Ty); 105 106 /// If Ty is a vector type, return a Constant with a splat of the given 107 /// value. Otherwise return a ConstantInt for the given value. 108 static Constant *get(Type *Ty, uint64_t V, bool isSigned = false); 109 110 /// Return a ConstantInt with the specified integer value for the specified 111 /// type. If the type is wider than 64 bits, the value will be zero-extended 112 /// to fit the type, unless isSigned is true, in which case the value will 113 /// be interpreted as a 64-bit signed integer and sign-extended to fit 114 /// the type. 115 /// @brief Get a ConstantInt for a specific value. 116 static ConstantInt *get(IntegerType *Ty, uint64_t V, 117 bool isSigned = false); 118 119 /// Return a ConstantInt with the specified value for the specified type. The 120 /// value V will be canonicalized to a an unsigned APInt. Accessing it with 121 /// either getSExtValue() or getZExtValue() will yield a correctly sized and 122 /// signed value for the type Ty. 123 /// @brief Get a ConstantInt for a specific signed value. 124 static ConstantInt *getSigned(IntegerType *Ty, int64_t V); 125 static Constant *getSigned(Type *Ty, int64_t V); 126 127 /// Return a ConstantInt with the specified value and an implied Type. The 128 /// type is the integer type that corresponds to the bit width of the value. 129 static ConstantInt *get(LLVMContext &Context, const APInt &V); 130 131 /// Return a ConstantInt constructed from the string strStart with the given 132 /// radix. 133 static ConstantInt *get(IntegerType *Ty, StringRef Str, 134 uint8_t radix); 135 136 /// If Ty is a vector type, return a Constant with a splat of the given 137 /// value. Otherwise return a ConstantInt for the given value. 138 static Constant *get(Type* Ty, const APInt& V); 139 140 /// Return the constant as an APInt value reference. This allows clients to 141 /// obtain a full-precision copy of the value. 142 /// @brief Return the constant's value. 143 inline const APInt &getValue() const { 144 return Val; 145 } 146 147 /// getBitWidth - Return the bitwidth of this constant. 148 unsigned getBitWidth() const { return Val.getBitWidth(); } 149 150 /// Return the constant as a 64-bit unsigned integer value after it 151 /// has been zero extended as appropriate for the type of this constant. Note 152 /// that this method can assert if the value does not fit in 64 bits. 153 /// @brief Return the zero extended value. 154 inline uint64_t getZExtValue() const { 155 return Val.getZExtValue(); 156 } 157 158 /// Return the constant as a 64-bit integer value after it has been sign 159 /// extended as appropriate for the type of this constant. Note that 160 /// this method can assert if the value does not fit in 64 bits. 161 /// @brief Return the sign extended value. 162 inline int64_t getSExtValue() const { 163 return Val.getSExtValue(); 164 } 165 166 /// A helper method that can be used to determine if the constant contained 167 /// within is equal to a constant. This only works for very small values, 168 /// because this is all that can be represented with all types. 169 /// @brief Determine if this constant's value is same as an unsigned char. 170 bool equalsInt(uint64_t V) const { 171 return Val == V; 172 } 173 174 /// getType - Specialize the getType() method to always return an IntegerType, 175 /// which reduces the amount of casting needed in parts of the compiler. 176 /// 177 inline IntegerType *getType() const { 178 return cast<IntegerType>(Value::getType()); 179 } 180 181 /// This static method returns true if the type Ty is big enough to 182 /// represent the value V. This can be used to avoid having the get method 183 /// assert when V is larger than Ty can represent. Note that there are two 184 /// versions of this method, one for unsigned and one for signed integers. 185 /// Although ConstantInt canonicalizes everything to an unsigned integer, 186 /// the signed version avoids callers having to convert a signed quantity 187 /// to the appropriate unsigned type before calling the method. 188 /// @returns true if V is a valid value for type Ty 189 /// @brief Determine if the value is in range for the given type. 190 static bool isValueValidForType(Type *Ty, uint64_t V); 191 static bool isValueValidForType(Type *Ty, int64_t V); 192 193 bool isNegative() const { return Val.isNegative(); } 194 195 /// This is just a convenience method to make client code smaller for a 196 /// common code. It also correctly performs the comparison without the 197 /// potential for an assertion from getZExtValue(). 198 bool isZero() const { 199 return Val == 0; 200 } 201 202 /// This is just a convenience method to make client code smaller for a 203 /// common case. It also correctly performs the comparison without the 204 /// potential for an assertion from getZExtValue(). 205 /// @brief Determine if the value is one. 206 bool isOne() const { 207 return Val == 1; 208 } 209 210 /// This function will return true iff every bit in this constant is set 211 /// to true. 212 /// @returns true iff this constant's bits are all set to true. 213 /// @brief Determine if the value is all ones. 214 bool isMinusOne() const { 215 return Val.isAllOnesValue(); 216 } 217 218 /// This function will return true iff this constant represents the largest 219 /// value that may be represented by the constant's type. 220 /// @returns true iff this is the largest value that may be represented 221 /// by this type. 222 /// @brief Determine if the value is maximal. 223 bool isMaxValue(bool isSigned) const { 224 if (isSigned) 225 return Val.isMaxSignedValue(); 226 else 227 return Val.isMaxValue(); 228 } 229 230 /// This function will return true iff this constant represents the smallest 231 /// value that may be represented by this constant's type. 232 /// @returns true if this is the smallest value that may be represented by 233 /// this type. 234 /// @brief Determine if the value is minimal. 235 bool isMinValue(bool isSigned) const { 236 if (isSigned) 237 return Val.isMinSignedValue(); 238 else 239 return Val.isMinValue(); 240 } 241 242 /// This function will return true iff this constant represents a value with 243 /// active bits bigger than 64 bits or a value greater than the given uint64_t 244 /// value. 245 /// @returns true iff this constant is greater or equal to the given number. 246 /// @brief Determine if the value is greater or equal to the given number. 247 bool uge(uint64_t Num) const { 248 return Val.getActiveBits() > 64 || Val.getZExtValue() >= Num; 249 } 250 251 /// getLimitedValue - If the value is smaller than the specified limit, 252 /// return it, otherwise return the limit value. This causes the value 253 /// to saturate to the limit. 254 /// @returns the min of the value of the constant and the specified value 255 /// @brief Get the constant's value with a saturation limit 256 uint64_t getLimitedValue(uint64_t Limit = ~0ULL) const { 257 return Val.getLimitedValue(Limit); 258 } 259 260 /// @brief Methods to support type inquiry through isa, cast, and dyn_cast. 261 static bool classof(const Value *V) { 262 return V->getValueID() == ConstantIntVal; 263 } 264 }; 265 266 //===----------------------------------------------------------------------===// 267 /// ConstantFP - Floating Point Values [float, double] 268 /// 269 class ConstantFP final : public ConstantData { 270 friend class Constant; 271 272 APFloat Val; 273 274 ConstantFP(Type *Ty, const APFloat& V); 275 276 void anchor() override; 277 void destroyConstantImpl(); 278 279 public: 280 ConstantFP(const ConstantFP &) = delete; 281 282 /// Floating point negation must be implemented with f(x) = -0.0 - x. This 283 /// method returns the negative zero constant for floating point or vector 284 /// floating point types; for all other types, it returns the null value. 285 static Constant *getZeroValueForNegation(Type *Ty); 286 287 /// This returns a ConstantFP, or a vector containing a splat of a ConstantFP, 288 /// for the specified value in the specified type. This should only be used 289 /// for simple constant values like 2.0/1.0 etc, that are known-valid both as 290 /// host double and as the target format. 291 static Constant *get(Type* Ty, double V); 292 static Constant *get(Type* Ty, StringRef Str); 293 static ConstantFP *get(LLVMContext &Context, const APFloat &V); 294 static Constant *getNaN(Type *Ty, bool Negative = false, unsigned type = 0); 295 static Constant *getNegativeZero(Type *Ty); 296 static Constant *getInfinity(Type *Ty, bool Negative = false); 297 298 /// Return true if Ty is big enough to represent V. 299 static bool isValueValidForType(Type *Ty, const APFloat &V); 300 inline const APFloat &getValueAPF() const { return Val; } 301 302 /// Return true if the value is positive or negative zero. 303 bool isZero() const { return Val.isZero(); } 304 305 /// Return true if the sign bit is set. 306 bool isNegative() const { return Val.isNegative(); } 307 308 /// Return true if the value is infinity 309 bool isInfinity() const { return Val.isInfinity(); } 310 311 /// Return true if the value is a NaN. 312 bool isNaN() const { return Val.isNaN(); } 313 314 /// We don't rely on operator== working on double values, as it returns true 315 /// for things that are clearly not equal, like -0.0 and 0.0. 316 /// As such, this method can be used to do an exact bit-for-bit comparison of 317 /// two floating point values. The version with a double operand is retained 318 /// because it's so convenient to write isExactlyValue(2.0), but please use 319 /// it only for simple constants. 320 bool isExactlyValue(const APFloat &V) const; 321 322 bool isExactlyValue(double V) const { 323 bool ignored; 324 APFloat FV(V); 325 FV.convert(Val.getSemantics(), APFloat::rmNearestTiesToEven, &ignored); 326 return isExactlyValue(FV); 327 } 328 329 /// Methods for support type inquiry through isa, cast, and dyn_cast: 330 static bool classof(const Value *V) { 331 return V->getValueID() == ConstantFPVal; 332 } 333 }; 334 335 //===----------------------------------------------------------------------===// 336 /// All zero aggregate value 337 /// 338 class ConstantAggregateZero final : public ConstantData { 339 friend class Constant; 340 341 explicit ConstantAggregateZero(Type *Ty) 342 : ConstantData(Ty, ConstantAggregateZeroVal) {} 343 344 void destroyConstantImpl(); 345 346 public: 347 ConstantAggregateZero(const ConstantAggregateZero &) = delete; 348 349 static ConstantAggregateZero *get(Type *Ty); 350 351 /// If this CAZ has array or vector type, return a zero with the right element 352 /// type. 353 Constant *getSequentialElement() const; 354 355 /// If this CAZ has struct type, return a zero with the right element type for 356 /// the specified element. 357 Constant *getStructElement(unsigned Elt) const; 358 359 /// Return a zero of the right value for the specified GEP index if we can, 360 /// otherwise return null (e.g. if C is a ConstantExpr). 361 Constant *getElementValue(Constant *C) const; 362 363 /// Return a zero of the right value for the specified GEP index. 364 Constant *getElementValue(unsigned Idx) const; 365 366 /// Return the number of elements in the array, vector, or struct. 367 unsigned getNumElements() const; 368 369 /// Methods for support type inquiry through isa, cast, and dyn_cast: 370 /// 371 static bool classof(const Value *V) { 372 return V->getValueID() == ConstantAggregateZeroVal; 373 } 374 }; 375 376 /// Base class for aggregate constants (with operands). 377 /// 378 /// These constants are aggregates of other constants, which are stored as 379 /// operands. 380 /// 381 /// Subclasses are \a ConstantStruct, \a ConstantArray, and \a 382 /// ConstantVector. 383 /// 384 /// \note Some subclasses of \a ConstantData are semantically aggregates -- 385 /// such as \a ConstantDataArray -- but are not subclasses of this because they 386 /// use operands. 387 class ConstantAggregate : public Constant { 388 protected: 389 ConstantAggregate(CompositeType *T, ValueTy VT, ArrayRef<Constant *> V); 390 391 public: 392 /// Transparently provide more efficient getOperand methods. 393 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); 394 395 /// Methods for support type inquiry through isa, cast, and dyn_cast: 396 static bool classof(const Value *V) { 397 return V->getValueID() >= ConstantAggregateFirstVal && 398 V->getValueID() <= ConstantAggregateLastVal; 399 } 400 }; 401 402 template <> 403 struct OperandTraits<ConstantAggregate> 404 : public VariadicOperandTraits<ConstantAggregate> {}; 405 406 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantAggregate, Constant) 407 408 //===----------------------------------------------------------------------===// 409 /// ConstantArray - Constant Array Declarations 410 /// 411 class ConstantArray final : public ConstantAggregate { 412 friend struct ConstantAggrKeyType<ConstantArray>; 413 friend class Constant; 414 415 ConstantArray(ArrayType *T, ArrayRef<Constant *> Val); 416 417 void destroyConstantImpl(); 418 Value *handleOperandChangeImpl(Value *From, Value *To); 419 420 public: 421 // ConstantArray accessors 422 static Constant *get(ArrayType *T, ArrayRef<Constant*> V); 423 424 private: 425 static Constant *getImpl(ArrayType *T, ArrayRef<Constant *> V); 426 427 public: 428 /// Specialize the getType() method to always return an ArrayType, 429 /// which reduces the amount of casting needed in parts of the compiler. 430 inline ArrayType *getType() const { 431 return cast<ArrayType>(Value::getType()); 432 } 433 434 /// Methods for support type inquiry through isa, cast, and dyn_cast: 435 static bool classof(const Value *V) { 436 return V->getValueID() == ConstantArrayVal; 437 } 438 }; 439 440 //===----------------------------------------------------------------------===// 441 // Constant Struct Declarations 442 // 443 class ConstantStruct final : public ConstantAggregate { 444 friend struct ConstantAggrKeyType<ConstantStruct>; 445 friend class Constant; 446 447 ConstantStruct(StructType *T, ArrayRef<Constant *> Val); 448 449 void destroyConstantImpl(); 450 Value *handleOperandChangeImpl(Value *From, Value *To); 451 452 public: 453 // ConstantStruct accessors 454 static Constant *get(StructType *T, ArrayRef<Constant*> V); 455 static Constant *get(StructType *T, ...) LLVM_END_WITH_NULL; 456 457 /// Return an anonymous struct that has the specified elements. 458 /// If the struct is possibly empty, then you must specify a context. 459 static Constant *getAnon(ArrayRef<Constant*> V, bool Packed = false) { 460 return get(getTypeForElements(V, Packed), V); 461 } 462 static Constant *getAnon(LLVMContext &Ctx, 463 ArrayRef<Constant*> V, bool Packed = false) { 464 return get(getTypeForElements(Ctx, V, Packed), V); 465 } 466 467 /// Return an anonymous struct type to use for a constant with the specified 468 /// set of elements. The list must not be empty. 469 static StructType *getTypeForElements(ArrayRef<Constant*> V, 470 bool Packed = false); 471 /// This version of the method allows an empty list. 472 static StructType *getTypeForElements(LLVMContext &Ctx, 473 ArrayRef<Constant*> V, 474 bool Packed = false); 475 476 /// Specialization - reduce amount of casting. 477 inline StructType *getType() const { 478 return cast<StructType>(Value::getType()); 479 } 480 481 /// Methods for support type inquiry through isa, cast, and dyn_cast: 482 static bool classof(const Value *V) { 483 return V->getValueID() == ConstantStructVal; 484 } 485 }; 486 487 //===----------------------------------------------------------------------===// 488 /// Constant Vector Declarations 489 /// 490 class ConstantVector final : public ConstantAggregate { 491 friend struct ConstantAggrKeyType<ConstantVector>; 492 friend class Constant; 493 494 ConstantVector(VectorType *T, ArrayRef<Constant *> Val); 495 496 void destroyConstantImpl(); 497 Value *handleOperandChangeImpl(Value *From, Value *To); 498 499 public: 500 // ConstantVector accessors 501 static Constant *get(ArrayRef<Constant*> V); 502 503 private: 504 static Constant *getImpl(ArrayRef<Constant *> V); 505 506 public: 507 /// Return a ConstantVector with the specified constant in each element. 508 static Constant *getSplat(unsigned NumElts, Constant *Elt); 509 510 /// Specialize the getType() method to always return a VectorType, 511 /// which reduces the amount of casting needed in parts of the compiler. 512 inline VectorType *getType() const { 513 return cast<VectorType>(Value::getType()); 514 } 515 516 /// If this is a splat constant, meaning that all of the elements have the 517 /// same value, return that value. Otherwise return NULL. 518 Constant *getSplatValue() const; 519 520 /// Methods for support type inquiry through isa, cast, and dyn_cast: 521 static bool classof(const Value *V) { 522 return V->getValueID() == ConstantVectorVal; 523 } 524 }; 525 526 //===----------------------------------------------------------------------===// 527 /// A constant pointer value that points to null 528 /// 529 class ConstantPointerNull final : public ConstantData { 530 friend class Constant; 531 532 explicit ConstantPointerNull(PointerType *T) 533 : ConstantData(T, Value::ConstantPointerNullVal) {} 534 535 void destroyConstantImpl(); 536 537 public: 538 ConstantPointerNull(const ConstantPointerNull &) = delete; 539 540 /// Static factory methods - Return objects of the specified value 541 static ConstantPointerNull *get(PointerType *T); 542 543 /// Specialize the getType() method to always return an PointerType, 544 /// which reduces the amount of casting needed in parts of the compiler. 545 inline PointerType *getType() const { 546 return cast<PointerType>(Value::getType()); 547 } 548 549 /// Methods for support type inquiry through isa, cast, and dyn_cast: 550 static bool classof(const Value *V) { 551 return V->getValueID() == ConstantPointerNullVal; 552 } 553 }; 554 555 //===----------------------------------------------------------------------===// 556 /// ConstantDataSequential - A vector or array constant whose element type is a 557 /// simple 1/2/4/8-byte integer or float/double, and whose elements are just 558 /// simple data values (i.e. ConstantInt/ConstantFP). This Constant node has no 559 /// operands because it stores all of the elements of the constant as densely 560 /// packed data, instead of as Value*'s. 561 /// 562 /// This is the common base class of ConstantDataArray and ConstantDataVector. 563 /// 564 class ConstantDataSequential : public ConstantData { 565 friend class LLVMContextImpl; 566 friend class Constant; 567 568 /// A pointer to the bytes underlying this constant (which is owned by the 569 /// uniquing StringMap). 570 const char *DataElements; 571 572 /// This forms a link list of ConstantDataSequential nodes that have 573 /// the same value but different type. For example, 0,0,0,1 could be a 4 574 /// element array of i8, or a 1-element array of i32. They'll both end up in 575 /// the same StringMap bucket, linked up. 576 ConstantDataSequential *Next; 577 578 void destroyConstantImpl(); 579 580 protected: 581 explicit ConstantDataSequential(Type *ty, ValueTy VT, const char *Data) 582 : ConstantData(ty, VT), DataElements(Data), Next(nullptr) {} 583 ~ConstantDataSequential() override { delete Next; } 584 585 static Constant *getImpl(StringRef Bytes, Type *Ty); 586 587 public: 588 ConstantDataSequential(const ConstantDataSequential &) = delete; 589 590 /// Return true if a ConstantDataSequential can be formed with a vector or 591 /// array of the specified element type. 592 /// ConstantDataArray only works with normal float and int types that are 593 /// stored densely in memory, not with things like i42 or x86_f80. 594 static bool isElementTypeCompatible(Type *Ty); 595 596 /// If this is a sequential container of integers (of any size), return the 597 /// specified element in the low bits of a uint64_t. 598 uint64_t getElementAsInteger(unsigned i) const; 599 600 /// If this is a sequential container of floating point type, return the 601 /// specified element as an APFloat. 602 APFloat getElementAsAPFloat(unsigned i) const; 603 604 /// If this is an sequential container of floats, return the specified element 605 /// as a float. 606 float getElementAsFloat(unsigned i) const; 607 608 /// If this is an sequential container of doubles, return the specified 609 /// element as a double. 610 double getElementAsDouble(unsigned i) const; 611 612 /// Return a Constant for a specified index's element. 613 /// Note that this has to compute a new constant to return, so it isn't as 614 /// efficient as getElementAsInteger/Float/Double. 615 Constant *getElementAsConstant(unsigned i) const; 616 617 /// Specialize the getType() method to always return a SequentialType, which 618 /// reduces the amount of casting needed in parts of the compiler. 619 inline SequentialType *getType() const { 620 return cast<SequentialType>(Value::getType()); 621 } 622 623 /// Return the element type of the array/vector. 624 Type *getElementType() const; 625 626 /// Return the number of elements in the array or vector. 627 unsigned getNumElements() const; 628 629 /// Return the size (in bytes) of each element in the array/vector. 630 /// The size of the elements is known to be a multiple of one byte. 631 uint64_t getElementByteSize() const; 632 633 /// This method returns true if this is an array of i8. 634 bool isString() const; 635 636 /// This method returns true if the array "isString", ends with a null byte, 637 /// and does not contains any other null bytes. 638 bool isCString() const; 639 640 /// If this array is isString(), then this method returns the array as a 641 /// StringRef. Otherwise, it asserts out. 642 StringRef getAsString() const { 643 assert(isString() && "Not a string"); 644 return getRawDataValues(); 645 } 646 647 /// If this array is isCString(), then this method returns the array (without 648 /// the trailing null byte) as a StringRef. Otherwise, it asserts out. 649 StringRef getAsCString() const { 650 assert(isCString() && "Isn't a C string"); 651 StringRef Str = getAsString(); 652 return Str.substr(0, Str.size()-1); 653 } 654 655 /// Return the raw, underlying, bytes of this data. Note that this is an 656 /// extremely tricky thing to work with, as it exposes the host endianness of 657 /// the data elements. 658 StringRef getRawDataValues() const; 659 660 /// Methods for support type inquiry through isa, cast, and dyn_cast: 661 static bool classof(const Value *V) { 662 return V->getValueID() == ConstantDataArrayVal || 663 V->getValueID() == ConstantDataVectorVal; 664 } 665 666 private: 667 const char *getElementPointer(unsigned Elt) const; 668 }; 669 670 //===----------------------------------------------------------------------===// 671 /// An array constant whose element type is a simple 1/2/4/8-byte integer or 672 /// float/double, and whose elements are just simple data values 673 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it 674 /// stores all of the elements of the constant as densely packed data, instead 675 /// of as Value*'s. 676 class ConstantDataArray final : public ConstantDataSequential { 677 friend class ConstantDataSequential; 678 679 explicit ConstantDataArray(Type *ty, const char *Data) 680 : ConstantDataSequential(ty, ConstantDataArrayVal, Data) {} 681 682 /// Allocate space for exactly zero operands. 683 void *operator new(size_t s) { 684 return User::operator new(s, 0); 685 } 686 687 void anchor() override; 688 689 public: 690 ConstantDataArray(const ConstantDataArray &) = delete; 691 692 void *operator new(size_t, unsigned) = delete; 693 694 /// get() constructors - Return a constant with array type with an element 695 /// count and element type matching the ArrayRef passed in. Note that this 696 /// can return a ConstantAggregateZero object. 697 static Constant *get(LLVMContext &Context, ArrayRef<uint8_t> Elts); 698 static Constant *get(LLVMContext &Context, ArrayRef<uint16_t> Elts); 699 static Constant *get(LLVMContext &Context, ArrayRef<uint32_t> Elts); 700 static Constant *get(LLVMContext &Context, ArrayRef<uint64_t> Elts); 701 static Constant *get(LLVMContext &Context, ArrayRef<float> Elts); 702 static Constant *get(LLVMContext &Context, ArrayRef<double> Elts); 703 704 /// getFP() constructors - Return a constant with array type with an element 705 /// count and element type of float with precision matching the number of 706 /// bits in the ArrayRef passed in. (i.e. half for 16bits, float for 32bits, 707 /// double for 64bits) Note that this can return a ConstantAggregateZero 708 /// object. 709 static Constant *getFP(LLVMContext &Context, ArrayRef<uint16_t> Elts); 710 static Constant *getFP(LLVMContext &Context, ArrayRef<uint32_t> Elts); 711 static Constant *getFP(LLVMContext &Context, ArrayRef<uint64_t> Elts); 712 713 /// This method constructs a CDS and initializes it with a text string. 714 /// The default behavior (AddNull==true) causes a null terminator to 715 /// be placed at the end of the array (increasing the length of the string by 716 /// one more than the StringRef would normally indicate. Pass AddNull=false 717 /// to disable this behavior. 718 static Constant *getString(LLVMContext &Context, StringRef Initializer, 719 bool AddNull = true); 720 721 /// Specialize the getType() method to always return an ArrayType, 722 /// which reduces the amount of casting needed in parts of the compiler. 723 inline ArrayType *getType() const { 724 return cast<ArrayType>(Value::getType()); 725 } 726 727 /// Methods for support type inquiry through isa, cast, and dyn_cast: 728 static bool classof(const Value *V) { 729 return V->getValueID() == ConstantDataArrayVal; 730 } 731 }; 732 733 //===----------------------------------------------------------------------===// 734 /// A vector constant whose element type is a simple 1/2/4/8-byte integer or 735 /// float/double, and whose elements are just simple data values 736 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it 737 /// stores all of the elements of the constant as densely packed data, instead 738 /// of as Value*'s. 739 class ConstantDataVector final : public ConstantDataSequential { 740 friend class ConstantDataSequential; 741 742 explicit ConstantDataVector(Type *ty, const char *Data) 743 : ConstantDataSequential(ty, ConstantDataVectorVal, Data) {} 744 745 // allocate space for exactly zero operands. 746 void *operator new(size_t s) { 747 return User::operator new(s, 0); 748 } 749 750 void anchor() override; 751 752 public: 753 ConstantDataVector(const ConstantDataVector &) = delete; 754 755 void *operator new(size_t, unsigned) = delete; 756 757 /// get() constructors - Return a constant with vector type with an element 758 /// count and element type matching the ArrayRef passed in. Note that this 759 /// can return a ConstantAggregateZero object. 760 static Constant *get(LLVMContext &Context, ArrayRef<uint8_t> Elts); 761 static Constant *get(LLVMContext &Context, ArrayRef<uint16_t> Elts); 762 static Constant *get(LLVMContext &Context, ArrayRef<uint32_t> Elts); 763 static Constant *get(LLVMContext &Context, ArrayRef<uint64_t> Elts); 764 static Constant *get(LLVMContext &Context, ArrayRef<float> Elts); 765 static Constant *get(LLVMContext &Context, ArrayRef<double> Elts); 766 767 /// getFP() constructors - Return a constant with vector type with an element 768 /// count and element type of float with the precision matching the number of 769 /// bits in the ArrayRef passed in. (i.e. half for 16bits, float for 32bits, 770 /// double for 64bits) Note that this can return a ConstantAggregateZero 771 /// object. 772 static Constant *getFP(LLVMContext &Context, ArrayRef<uint16_t> Elts); 773 static Constant *getFP(LLVMContext &Context, ArrayRef<uint32_t> Elts); 774 static Constant *getFP(LLVMContext &Context, ArrayRef<uint64_t> Elts); 775 776 /// Return a ConstantVector with the specified constant in each element. 777 /// The specified constant has to be a of a compatible type (i8/i16/ 778 /// i32/i64/float/double) and must be a ConstantFP or ConstantInt. 779 static Constant *getSplat(unsigned NumElts, Constant *Elt); 780 781 /// If this is a splat constant, meaning that all of the elements have the 782 /// same value, return that value. Otherwise return NULL. 783 Constant *getSplatValue() const; 784 785 /// Specialize the getType() method to always return a VectorType, 786 /// which reduces the amount of casting needed in parts of the compiler. 787 inline VectorType *getType() const { 788 return cast<VectorType>(Value::getType()); 789 } 790 791 /// Methods for support type inquiry through isa, cast, and dyn_cast: 792 static bool classof(const Value *V) { 793 return V->getValueID() == ConstantDataVectorVal; 794 } 795 }; 796 797 //===----------------------------------------------------------------------===// 798 /// A constant token which is empty 799 /// 800 class ConstantTokenNone final : public ConstantData { 801 friend class Constant; 802 803 explicit ConstantTokenNone(LLVMContext &Context) 804 : ConstantData(Type::getTokenTy(Context), ConstantTokenNoneVal) {} 805 806 void destroyConstantImpl(); 807 808 public: 809 ConstantTokenNone(const ConstantTokenNone &) = delete; 810 811 /// Return the ConstantTokenNone. 812 static ConstantTokenNone *get(LLVMContext &Context); 813 814 /// @brief Methods to support type inquiry through isa, cast, and dyn_cast. 815 static bool classof(const Value *V) { 816 return V->getValueID() == ConstantTokenNoneVal; 817 } 818 }; 819 820 /// The address of a basic block. 821 /// 822 class BlockAddress final : public Constant { 823 friend class Constant; 824 825 BlockAddress(Function *F, BasicBlock *BB); 826 827 void *operator new(size_t s) { return User::operator new(s, 2); } 828 829 void destroyConstantImpl(); 830 Value *handleOperandChangeImpl(Value *From, Value *To); 831 832 public: 833 void *operator new(size_t, unsigned) = delete; 834 835 /// Return a BlockAddress for the specified function and basic block. 836 static BlockAddress *get(Function *F, BasicBlock *BB); 837 838 /// Return a BlockAddress for the specified basic block. The basic 839 /// block must be embedded into a function. 840 static BlockAddress *get(BasicBlock *BB); 841 842 /// Lookup an existing \c BlockAddress constant for the given BasicBlock. 843 /// 844 /// \returns 0 if \c !BB->hasAddressTaken(), otherwise the \c BlockAddress. 845 static BlockAddress *lookup(const BasicBlock *BB); 846 847 /// Transparently provide more efficient getOperand methods. 848 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value); 849 850 Function *getFunction() const { return (Function*)Op<0>().get(); } 851 BasicBlock *getBasicBlock() const { return (BasicBlock*)Op<1>().get(); } 852 853 /// Methods for support type inquiry through isa, cast, and dyn_cast: 854 static inline bool classof(const Value *V) { 855 return V->getValueID() == BlockAddressVal; 856 } 857 }; 858 859 template <> 860 struct OperandTraits<BlockAddress> : 861 public FixedNumOperandTraits<BlockAddress, 2> { 862 }; 863 864 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BlockAddress, Value) 865 866 //===----------------------------------------------------------------------===// 867 /// A constant value that is initialized with an expression using 868 /// other constant values. 869 /// 870 /// This class uses the standard Instruction opcodes to define the various 871 /// constant expressions. The Opcode field for the ConstantExpr class is 872 /// maintained in the Value::SubclassData field. 873 class ConstantExpr : public Constant { 874 friend struct ConstantExprKeyType; 875 friend class Constant; 876 877 void destroyConstantImpl(); 878 Value *handleOperandChangeImpl(Value *From, Value *To); 879 880 protected: 881 ConstantExpr(Type *ty, unsigned Opcode, Use *Ops, unsigned NumOps) 882 : Constant(ty, ConstantExprVal, Ops, NumOps) { 883 // Operation type (an Instruction opcode) is stored as the SubclassData. 884 setValueSubclassData(Opcode); 885 } 886 887 public: 888 // Static methods to construct a ConstantExpr of different kinds. Note that 889 // these methods may return a object that is not an instance of the 890 // ConstantExpr class, because they will attempt to fold the constant 891 // expression into something simpler if possible. 892 893 /// getAlignOf constant expr - computes the alignment of a type in a target 894 /// independent way (Note: the return type is an i64). 895 static Constant *getAlignOf(Type *Ty); 896 897 /// getSizeOf constant expr - computes the (alloc) size of a type (in 898 /// address-units, not bits) in a target independent way (Note: the return 899 /// type is an i64). 900 /// 901 static Constant *getSizeOf(Type *Ty); 902 903 /// getOffsetOf constant expr - computes the offset of a struct field in a 904 /// target independent way (Note: the return type is an i64). 905 /// 906 static Constant *getOffsetOf(StructType *STy, unsigned FieldNo); 907 908 /// getOffsetOf constant expr - This is a generalized form of getOffsetOf, 909 /// which supports any aggregate type, and any Constant index. 910 /// 911 static Constant *getOffsetOf(Type *Ty, Constant *FieldNo); 912 913 static Constant *getNeg(Constant *C, bool HasNUW = false, bool HasNSW =false); 914 static Constant *getFNeg(Constant *C); 915 static Constant *getNot(Constant *C); 916 static Constant *getAdd(Constant *C1, Constant *C2, 917 bool HasNUW = false, bool HasNSW = false); 918 static Constant *getFAdd(Constant *C1, Constant *C2); 919 static Constant *getSub(Constant *C1, Constant *C2, 920 bool HasNUW = false, bool HasNSW = false); 921 static Constant *getFSub(Constant *C1, Constant *C2); 922 static Constant *getMul(Constant *C1, Constant *C2, 923 bool HasNUW = false, bool HasNSW = false); 924 static Constant *getFMul(Constant *C1, Constant *C2); 925 static Constant *getUDiv(Constant *C1, Constant *C2, bool isExact = false); 926 static Constant *getSDiv(Constant *C1, Constant *C2, bool isExact = false); 927 static Constant *getFDiv(Constant *C1, Constant *C2); 928 static Constant *getURem(Constant *C1, Constant *C2); 929 static Constant *getSRem(Constant *C1, Constant *C2); 930 static Constant *getFRem(Constant *C1, Constant *C2); 931 static Constant *getAnd(Constant *C1, Constant *C2); 932 static Constant *getOr(Constant *C1, Constant *C2); 933 static Constant *getXor(Constant *C1, Constant *C2); 934 static Constant *getShl(Constant *C1, Constant *C2, 935 bool HasNUW = false, bool HasNSW = false); 936 static Constant *getLShr(Constant *C1, Constant *C2, bool isExact = false); 937 static Constant *getAShr(Constant *C1, Constant *C2, bool isExact = false); 938 static Constant *getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced = false); 939 static Constant *getSExt(Constant *C, Type *Ty, bool OnlyIfReduced = false); 940 static Constant *getZExt(Constant *C, Type *Ty, bool OnlyIfReduced = false); 941 static Constant *getFPTrunc(Constant *C, Type *Ty, 942 bool OnlyIfReduced = false); 943 static Constant *getFPExtend(Constant *C, Type *Ty, 944 bool OnlyIfReduced = false); 945 static Constant *getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false); 946 static Constant *getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false); 947 static Constant *getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced = false); 948 static Constant *getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced = false); 949 static Constant *getPtrToInt(Constant *C, Type *Ty, 950 bool OnlyIfReduced = false); 951 static Constant *getIntToPtr(Constant *C, Type *Ty, 952 bool OnlyIfReduced = false); 953 static Constant *getBitCast(Constant *C, Type *Ty, 954 bool OnlyIfReduced = false); 955 static Constant *getAddrSpaceCast(Constant *C, Type *Ty, 956 bool OnlyIfReduced = false); 957 958 static Constant *getNSWNeg(Constant *C) { return getNeg(C, false, true); } 959 static Constant *getNUWNeg(Constant *C) { return getNeg(C, true, false); } 960 961 static Constant *getNSWAdd(Constant *C1, Constant *C2) { 962 return getAdd(C1, C2, false, true); 963 } 964 965 static Constant *getNUWAdd(Constant *C1, Constant *C2) { 966 return getAdd(C1, C2, true, false); 967 } 968 969 static Constant *getNSWSub(Constant *C1, Constant *C2) { 970 return getSub(C1, C2, false, true); 971 } 972 973 static Constant *getNUWSub(Constant *C1, Constant *C2) { 974 return getSub(C1, C2, true, false); 975 } 976 977 static Constant *getNSWMul(Constant *C1, Constant *C2) { 978 return getMul(C1, C2, false, true); 979 } 980 981 static Constant *getNUWMul(Constant *C1, Constant *C2) { 982 return getMul(C1, C2, true, false); 983 } 984 985 static Constant *getNSWShl(Constant *C1, Constant *C2) { 986 return getShl(C1, C2, false, true); 987 } 988 989 static Constant *getNUWShl(Constant *C1, Constant *C2) { 990 return getShl(C1, C2, true, false); 991 } 992 993 static Constant *getExactSDiv(Constant *C1, Constant *C2) { 994 return getSDiv(C1, C2, true); 995 } 996 997 static Constant *getExactUDiv(Constant *C1, Constant *C2) { 998 return getUDiv(C1, C2, true); 999 } 1000 1001 static Constant *getExactAShr(Constant *C1, Constant *C2) { 1002 return getAShr(C1, C2, true); 1003 } 1004 1005 static Constant *getExactLShr(Constant *C1, Constant *C2) { 1006 return getLShr(C1, C2, true); 1007 } 1008 1009 /// Return the identity for the given binary operation, 1010 /// i.e. a constant C such that X op C = X and C op X = X for every X. It 1011 /// returns null if the operator doesn't have an identity. 1012 static Constant *getBinOpIdentity(unsigned Opcode, Type *Ty); 1013 1014 /// Return the absorbing element for the given binary 1015 /// operation, i.e. a constant C such that X op C = C and C op X = C for 1016 /// every X. For example, this returns zero for integer multiplication. 1017 /// It returns null if the operator doesn't have an absorbing element. 1018 static Constant *getBinOpAbsorber(unsigned Opcode, Type *Ty); 1019 1020 /// Transparently provide more efficient getOperand methods. 1021 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); 1022 1023 /// \brief Convenience function for getting a Cast operation. 1024 /// 1025 /// \param ops The opcode for the conversion 1026 /// \param C The constant to be converted 1027 /// \param Ty The type to which the constant is converted 1028 /// \param OnlyIfReduced see \a getWithOperands() docs. 1029 static Constant *getCast(unsigned ops, Constant *C, Type *Ty, 1030 bool OnlyIfReduced = false); 1031 1032 // @brief Create a ZExt or BitCast cast constant expression 1033 static Constant *getZExtOrBitCast( 1034 Constant *C, ///< The constant to zext or bitcast 1035 Type *Ty ///< The type to zext or bitcast C to 1036 ); 1037 1038 // @brief Create a SExt or BitCast cast constant expression 1039 static Constant *getSExtOrBitCast( 1040 Constant *C, ///< The constant to sext or bitcast 1041 Type *Ty ///< The type to sext or bitcast C to 1042 ); 1043 1044 // @brief Create a Trunc or BitCast cast constant expression 1045 static Constant *getTruncOrBitCast( 1046 Constant *C, ///< The constant to trunc or bitcast 1047 Type *Ty ///< The type to trunc or bitcast C to 1048 ); 1049 1050 /// @brief Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant 1051 /// expression. 1052 static Constant *getPointerCast( 1053 Constant *C, ///< The pointer value to be casted (operand 0) 1054 Type *Ty ///< The type to which cast should be made 1055 ); 1056 1057 /// @brief Create a BitCast or AddrSpaceCast for a pointer type depending on 1058 /// the address space. 1059 static Constant *getPointerBitCastOrAddrSpaceCast( 1060 Constant *C, ///< The constant to addrspacecast or bitcast 1061 Type *Ty ///< The type to bitcast or addrspacecast C to 1062 ); 1063 1064 /// @brief Create a ZExt, Bitcast or Trunc for integer -> integer casts 1065 static Constant *getIntegerCast( 1066 Constant *C, ///< The integer constant to be casted 1067 Type *Ty, ///< The integer type to cast to 1068 bool isSigned ///< Whether C should be treated as signed or not 1069 ); 1070 1071 /// @brief Create a FPExt, Bitcast or FPTrunc for fp -> fp casts 1072 static Constant *getFPCast( 1073 Constant *C, ///< The integer constant to be casted 1074 Type *Ty ///< The integer type to cast to 1075 ); 1076 1077 /// @brief Return true if this is a convert constant expression 1078 bool isCast() const; 1079 1080 /// @brief Return true if this is a compare constant expression 1081 bool isCompare() const; 1082 1083 /// @brief Return true if this is an insertvalue or extractvalue expression, 1084 /// and the getIndices() method may be used. 1085 bool hasIndices() const; 1086 1087 /// @brief Return true if this is a getelementptr expression and all 1088 /// the index operands are compile-time known integers within the 1089 /// corresponding notional static array extents. Note that this is 1090 /// not equivalant to, a subset of, or a superset of the "inbounds" 1091 /// property. 1092 bool isGEPWithNoNotionalOverIndexing() const; 1093 1094 /// Select constant expr 1095 /// 1096 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1097 static Constant *getSelect(Constant *C, Constant *V1, Constant *V2, 1098 Type *OnlyIfReducedTy = nullptr); 1099 1100 /// get - Return a binary or shift operator constant expression, 1101 /// folding if possible. 1102 /// 1103 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1104 static Constant *get(unsigned Opcode, Constant *C1, Constant *C2, 1105 unsigned Flags = 0, Type *OnlyIfReducedTy = nullptr); 1106 1107 /// \brief Return an ICmp or FCmp comparison operator constant expression. 1108 /// 1109 /// \param OnlyIfReduced see \a getWithOperands() docs. 1110 static Constant *getCompare(unsigned short pred, Constant *C1, Constant *C2, 1111 bool OnlyIfReduced = false); 1112 1113 /// get* - Return some common constants without having to 1114 /// specify the full Instruction::OPCODE identifier. 1115 /// 1116 static Constant *getICmp(unsigned short pred, Constant *LHS, Constant *RHS, 1117 bool OnlyIfReduced = false); 1118 static Constant *getFCmp(unsigned short pred, Constant *LHS, Constant *RHS, 1119 bool OnlyIfReduced = false); 1120 1121 /// Getelementptr form. Value* is only accepted for convenience; 1122 /// all elements must be Constants. 1123 /// 1124 /// \param InRangeIndex the inrange index if present or None. 1125 /// \param OnlyIfReducedTy see \a getWithOperands() docs. 1126 static Constant *getGetElementPtr(Type *Ty, Constant *C, 1127 ArrayRef<Constant *> IdxList, 1128 bool InBounds = false, 1129 Optional<unsigned> InRangeIndex = None, 1130 Type *OnlyIfReducedTy = nullptr) { 1131 return getGetElementPtr( 1132 Ty, C, makeArrayRef((Value * const *)IdxList.data(), IdxList.size()), 1133 InBounds, InRangeIndex, OnlyIfReducedTy); 1134 } 1135 static Constant *getGetElementPtr(Type *Ty, Constant *C, Constant *Idx, 1136 bool InBounds = false, 1137 Optional<unsigned> InRangeIndex = None, 1138 Type *OnlyIfReducedTy = nullptr) { 1139 // This form of the function only exists to avoid ambiguous overload 1140 // warnings about whether to convert Idx to ArrayRef<Constant *> or 1141 // ArrayRef<Value *>. 1142 return getGetElementPtr(Ty, C, cast<Value>(Idx), InBounds, InRangeIndex, 1143 OnlyIfReducedTy); 1144 } 1145 static Constant *getGetElementPtr(Type *Ty, Constant *C, 1146 ArrayRef<Value *> IdxList, 1147 bool InBounds = false, 1148 Optional<unsigned> InRangeIndex = None, 1149 Type *OnlyIfReducedTy = nullptr); 1150 1151 /// Create an "inbounds" getelementptr. See the documentation for the 1152 /// "inbounds" flag in LangRef.html for details. 1153 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1154 ArrayRef<Constant *> IdxList) { 1155 return getGetElementPtr(Ty, C, IdxList, true); 1156 } 1157 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1158 Constant *Idx) { 1159 // This form of the function only exists to avoid ambiguous overload 1160 // warnings about whether to convert Idx to ArrayRef<Constant *> or 1161 // ArrayRef<Value *>. 1162 return getGetElementPtr(Ty, C, Idx, true); 1163 } 1164 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C, 1165 ArrayRef<Value *> IdxList) { 1166 return getGetElementPtr(Ty, C, IdxList, true); 1167 } 1168 1169 static Constant *getExtractElement(Constant *Vec, Constant *Idx, 1170 Type *OnlyIfReducedTy = nullptr); 1171 static Constant *getInsertElement(Constant *Vec, Constant *Elt, Constant *Idx, 1172 Type *OnlyIfReducedTy = nullptr); 1173 static Constant *getShuffleVector(Constant *V1, Constant *V2, Constant *Mask, 1174 Type *OnlyIfReducedTy = nullptr); 1175 static Constant *getExtractValue(Constant *Agg, ArrayRef<unsigned> Idxs, 1176 Type *OnlyIfReducedTy = nullptr); 1177 static Constant *getInsertValue(Constant *Agg, Constant *Val, 1178 ArrayRef<unsigned> Idxs, 1179 Type *OnlyIfReducedTy = nullptr); 1180 1181 /// Return the opcode at the root of this constant expression 1182 unsigned getOpcode() const { return getSubclassDataFromValue(); } 1183 1184 /// Return the ICMP or FCMP predicate value. Assert if this is not an ICMP or 1185 /// FCMP constant expression. 1186 unsigned getPredicate() const; 1187 1188 /// Assert that this is an insertvalue or exactvalue 1189 /// expression and return the list of indices. 1190 ArrayRef<unsigned> getIndices() const; 1191 1192 /// Return a string representation for an opcode. 1193 const char *getOpcodeName() const; 1194 1195 /// Return a constant expression identical to this one, but with the specified 1196 /// operand set to the specified value. 1197 Constant *getWithOperandReplaced(unsigned OpNo, Constant *Op) const; 1198 1199 /// This returns the current constant expression with the operands replaced 1200 /// with the specified values. The specified array must have the same number 1201 /// of operands as our current one. 1202 Constant *getWithOperands(ArrayRef<Constant*> Ops) const { 1203 return getWithOperands(Ops, getType()); 1204 } 1205 1206 /// Get the current expression with the operands replaced. 1207 /// 1208 /// Return the current constant expression with the operands replaced with \c 1209 /// Ops and the type with \c Ty. The new operands must have the same number 1210 /// as the current ones. 1211 /// 1212 /// If \c OnlyIfReduced is \c true, nullptr will be returned unless something 1213 /// gets constant-folded, the type changes, or the expression is otherwise 1214 /// canonicalized. This parameter should almost always be \c false. 1215 Constant *getWithOperands(ArrayRef<Constant *> Ops, Type *Ty, 1216 bool OnlyIfReduced = false, 1217 Type *SrcTy = nullptr) const; 1218 1219 /// Returns an Instruction which implements the same operation as this 1220 /// ConstantExpr. The instruction is not linked to any basic block. 1221 /// 1222 /// A better approach to this could be to have a constructor for Instruction 1223 /// which would take a ConstantExpr parameter, but that would have spread 1224 /// implementation details of ConstantExpr outside of Constants.cpp, which 1225 /// would make it harder to remove ConstantExprs altogether. 1226 Instruction *getAsInstruction(); 1227 1228 /// Methods for support type inquiry through isa, cast, and dyn_cast: 1229 static inline bool classof(const Value *V) { 1230 return V->getValueID() == ConstantExprVal; 1231 } 1232 1233 private: 1234 // Shadow Value::setValueSubclassData with a private forwarding method so that 1235 // subclasses cannot accidentally use it. 1236 void setValueSubclassData(unsigned short D) { 1237 Value::setValueSubclassData(D); 1238 } 1239 }; 1240 1241 template <> 1242 struct OperandTraits<ConstantExpr> : 1243 public VariadicOperandTraits<ConstantExpr, 1> { 1244 }; 1245 1246 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantExpr, Constant) 1247 1248 //===----------------------------------------------------------------------===// 1249 /// 'undef' values are things that do not have specified contents. 1250 /// These are used for a variety of purposes, including global variable 1251 /// initializers and operands to instructions. 'undef' values can occur with 1252 /// any first-class type. 1253 /// 1254 /// Undef values aren't exactly constants; if they have multiple uses, they 1255 /// can appear to have different bit patterns at each use. See 1256 /// LangRef.html#undefvalues for details. 1257 /// 1258 class UndefValue final : public ConstantData { 1259 friend class Constant; 1260 1261 explicit UndefValue(Type *T) : ConstantData(T, UndefValueVal) {} 1262 1263 void destroyConstantImpl(); 1264 1265 public: 1266 UndefValue(const UndefValue &) = delete; 1267 1268 /// Static factory methods - Return an 'undef' object of the specified type. 1269 static UndefValue *get(Type *T); 1270 1271 /// If this Undef has array or vector type, return a undef with the right 1272 /// element type. 1273 UndefValue *getSequentialElement() const; 1274 1275 /// If this undef has struct type, return a undef with the right element type 1276 /// for the specified element. 1277 UndefValue *getStructElement(unsigned Elt) const; 1278 1279 /// Return an undef of the right value for the specified GEP index if we can, 1280 /// otherwise return null (e.g. if C is a ConstantExpr). 1281 UndefValue *getElementValue(Constant *C) const; 1282 1283 /// Return an undef of the right value for the specified GEP index. 1284 UndefValue *getElementValue(unsigned Idx) const; 1285 1286 /// Return the number of elements in the array, vector, or struct. 1287 unsigned getNumElements() const; 1288 1289 /// Methods for support type inquiry through isa, cast, and dyn_cast: 1290 static bool classof(const Value *V) { 1291 return V->getValueID() == UndefValueVal; 1292 } 1293 }; 1294 1295 } // end namespace llvm 1296 1297 #endif // LLVM_IR_CONSTANTS_H 1298