1 //===-- llvm/Constants.h - Constant class subclass definitions --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
19 //===----------------------------------------------------------------------===//
21 #ifndef LLVM_IR_CONSTANTS_H
22 #define LLVM_IR_CONSTANTS_H
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/STLExtras.h"
30 #include "llvm/ADT/StringRef.h"
31 #include "llvm/IR/Constant.h"
32 #include "llvm/IR/DerivedTypes.h"
33 #include "llvm/IR/OperandTraits.h"
34 #include "llvm/IR/User.h"
35 #include "llvm/IR/Value.h"
36 #include "llvm/Support/Casting.h"
37 #include "llvm/Support/Compiler.h"
38 #include "llvm/Support/ErrorHandling.h"
51 template <class ConstantClass> struct ConstantAggrKeyType;
53 /// Base class for constants with no operands.
55 /// These constants have no operands; they represent their data directly.
56 /// Since they can be in use by unrelated modules (and are never based on
57 /// GlobalValues), it never makes sense to RAUW them.
58 class ConstantData : public Constant {
59 friend class Constant;
61 Value *handleOperandChangeImpl(Value *From, Value *To) {
62 llvm_unreachable("Constant data does not have operands!");
66 explicit ConstantData(Type *Ty, ValueTy VT) : Constant(Ty, VT, nullptr, 0) {}
68 void *operator new(size_t s) { return User::operator new(s, 0); }
71 ConstantData(const ConstantData &) = delete;
73 /// Methods to support type inquiry through isa, cast, and dyn_cast.
74 static bool classof(const Value *V) {
75 return V->getValueID() >= ConstantDataFirstVal &&
76 V->getValueID() <= ConstantDataLastVal;
80 //===----------------------------------------------------------------------===//
81 /// This is the shared class of boolean and integer constants. This class
82 /// represents both boolean and integral constants.
83 /// Class for constant integers.
84 class ConstantInt final : public ConstantData {
85 friend class Constant;
89 ConstantInt(IntegerType *Ty, const APInt& V);
91 void destroyConstantImpl();
94 ConstantInt(const ConstantInt &) = delete;
96 static ConstantInt *getTrue(LLVMContext &Context);
97 static ConstantInt *getFalse(LLVMContext &Context);
98 static Constant *getTrue(Type *Ty);
99 static Constant *getFalse(Type *Ty);
101 /// If Ty is a vector type, return a Constant with a splat of the given
102 /// value. Otherwise return a ConstantInt for the given value.
103 static Constant *get(Type *Ty, uint64_t V, bool isSigned = false);
105 /// Return a ConstantInt with the specified integer value for the specified
106 /// type. If the type is wider than 64 bits, the value will be zero-extended
107 /// to fit the type, unless isSigned is true, in which case the value will
108 /// be interpreted as a 64-bit signed integer and sign-extended to fit
110 /// Get a ConstantInt for a specific value.
111 static ConstantInt *get(IntegerType *Ty, uint64_t V,
112 bool isSigned = false);
114 /// Return a ConstantInt with the specified value for the specified type. The
115 /// value V will be canonicalized to a an unsigned APInt. Accessing it with
116 /// either getSExtValue() or getZExtValue() will yield a correctly sized and
117 /// signed value for the type Ty.
118 /// Get a ConstantInt for a specific signed value.
119 static ConstantInt *getSigned(IntegerType *Ty, int64_t V);
120 static Constant *getSigned(Type *Ty, int64_t V);
122 /// Return a ConstantInt with the specified value and an implied Type. The
123 /// type is the integer type that corresponds to the bit width of the value.
124 static ConstantInt *get(LLVMContext &Context, const APInt &V);
126 /// Return a ConstantInt constructed from the string strStart with the given
128 static ConstantInt *get(IntegerType *Ty, StringRef Str,
131 /// If Ty is a vector type, return a Constant with a splat of the given
132 /// value. Otherwise return a ConstantInt for the given value.
133 static Constant *get(Type* Ty, const APInt& V);
135 /// Return the constant as an APInt value reference. This allows clients to
136 /// obtain a full-precision copy of the value.
137 /// Return the constant's value.
138 inline const APInt &getValue() const {
142 /// getBitWidth - Return the bitwidth of this constant.
143 unsigned getBitWidth() const { return Val.getBitWidth(); }
145 /// Return the constant as a 64-bit unsigned integer value after it
146 /// has been zero extended as appropriate for the type of this constant. Note
147 /// that this method can assert if the value does not fit in 64 bits.
148 /// Return the zero extended value.
149 inline uint64_t getZExtValue() const {
150 return Val.getZExtValue();
153 /// Return the constant as a 64-bit integer value after it has been sign
154 /// extended as appropriate for the type of this constant. Note that
155 /// this method can assert if the value does not fit in 64 bits.
156 /// Return the sign extended value.
157 inline int64_t getSExtValue() const {
158 return Val.getSExtValue();
161 /// A helper method that can be used to determine if the constant contained
162 /// within is equal to a constant. This only works for very small values,
163 /// because this is all that can be represented with all types.
164 /// Determine if this constant's value is same as an unsigned char.
165 bool equalsInt(uint64_t V) const {
169 /// getType - Specialize the getType() method to always return an IntegerType,
170 /// which reduces the amount of casting needed in parts of the compiler.
172 inline IntegerType *getType() const {
173 return cast<IntegerType>(Value::getType());
176 /// This static method returns true if the type Ty is big enough to
177 /// represent the value V. This can be used to avoid having the get method
178 /// assert when V is larger than Ty can represent. Note that there are two
179 /// versions of this method, one for unsigned and one for signed integers.
180 /// Although ConstantInt canonicalizes everything to an unsigned integer,
181 /// the signed version avoids callers having to convert a signed quantity
182 /// to the appropriate unsigned type before calling the method.
183 /// @returns true if V is a valid value for type Ty
184 /// Determine if the value is in range for the given type.
185 static bool isValueValidForType(Type *Ty, uint64_t V);
186 static bool isValueValidForType(Type *Ty, int64_t V);
188 bool isNegative() const { return Val.isNegative(); }
190 /// This is just a convenience method to make client code smaller for a
191 /// common code. It also correctly performs the comparison without the
192 /// potential for an assertion from getZExtValue().
193 bool isZero() const {
194 return Val.isNullValue();
197 /// This is just a convenience method to make client code smaller for a
198 /// common case. It also correctly performs the comparison without the
199 /// potential for an assertion from getZExtValue().
200 /// Determine if the value is one.
202 return Val.isOneValue();
205 /// This function will return true iff every bit in this constant is set
207 /// @returns true iff this constant's bits are all set to true.
208 /// Determine if the value is all ones.
209 bool isMinusOne() const {
210 return Val.isAllOnesValue();
213 /// This function will return true iff this constant represents the largest
214 /// value that may be represented by the constant's type.
215 /// @returns true iff this is the largest value that may be represented
217 /// Determine if the value is maximal.
218 bool isMaxValue(bool isSigned) const {
220 return Val.isMaxSignedValue();
222 return Val.isMaxValue();
225 /// This function will return true iff this constant represents the smallest
226 /// value that may be represented by this constant's type.
227 /// @returns true if this is the smallest value that may be represented by
229 /// Determine if the value is minimal.
230 bool isMinValue(bool isSigned) const {
232 return Val.isMinSignedValue();
234 return Val.isMinValue();
237 /// This function will return true iff this constant represents a value with
238 /// active bits bigger than 64 bits or a value greater than the given uint64_t
240 /// @returns true iff this constant is greater or equal to the given number.
241 /// Determine if the value is greater or equal to the given number.
242 bool uge(uint64_t Num) const {
246 /// getLimitedValue - If the value is smaller than the specified limit,
247 /// return it, otherwise return the limit value. This causes the value
248 /// to saturate to the limit.
249 /// @returns the min of the value of the constant and the specified value
250 /// Get the constant's value with a saturation limit
251 uint64_t getLimitedValue(uint64_t Limit = ~0ULL) const {
252 return Val.getLimitedValue(Limit);
255 /// Methods to support type inquiry through isa, cast, and dyn_cast.
256 static bool classof(const Value *V) {
257 return V->getValueID() == ConstantIntVal;
261 //===----------------------------------------------------------------------===//
262 /// ConstantFP - Floating Point Values [float, double]
264 class ConstantFP final : public ConstantData {
265 friend class Constant;
269 ConstantFP(Type *Ty, const APFloat& V);
271 void destroyConstantImpl();
274 ConstantFP(const ConstantFP &) = delete;
276 /// Floating point negation must be implemented with f(x) = -0.0 - x. This
277 /// method returns the negative zero constant for floating point or vector
278 /// floating point types; for all other types, it returns the null value.
279 static Constant *getZeroValueForNegation(Type *Ty);
281 /// This returns a ConstantFP, or a vector containing a splat of a ConstantFP,
282 /// for the specified value in the specified type. This should only be used
283 /// for simple constant values like 2.0/1.0 etc, that are known-valid both as
284 /// host double and as the target format.
285 static Constant *get(Type* Ty, double V);
287 /// If Ty is a vector type, return a Constant with a splat of the given
288 /// value. Otherwise return a ConstantFP for the given value.
289 static Constant *get(Type *Ty, const APFloat &V);
291 static Constant *get(Type* Ty, StringRef Str);
292 static ConstantFP *get(LLVMContext &Context, const APFloat &V);
293 static Constant *getNaN(Type *Ty, bool Negative = false, unsigned type = 0);
294 static Constant *getNegativeZero(Type *Ty);
295 static Constant *getInfinity(Type *Ty, bool Negative = false);
297 /// Return true if Ty is big enough to represent V.
298 static bool isValueValidForType(Type *Ty, const APFloat &V);
299 inline const APFloat &getValueAPF() const { return Val; }
301 /// Return true if the value is positive or negative zero.
302 bool isZero() const { return Val.isZero(); }
304 /// Return true if the sign bit is set.
305 bool isNegative() const { return Val.isNegative(); }
307 /// Return true if the value is infinity
308 bool isInfinity() const { return Val.isInfinity(); }
310 /// Return true if the value is a NaN.
311 bool isNaN() const { return Val.isNaN(); }
313 /// We don't rely on operator== working on double values, as it returns true
314 /// for things that are clearly not equal, like -0.0 and 0.0.
315 /// As such, this method can be used to do an exact bit-for-bit comparison of
316 /// two floating point values. The version with a double operand is retained
317 /// because it's so convenient to write isExactlyValue(2.0), but please use
318 /// it only for simple constants.
319 bool isExactlyValue(const APFloat &V) const;
321 bool isExactlyValue(double V) const {
324 FV.convert(Val.getSemantics(), APFloat::rmNearestTiesToEven, &ignored);
325 return isExactlyValue(FV);
328 /// Methods for support type inquiry through isa, cast, and dyn_cast:
329 static bool classof(const Value *V) {
330 return V->getValueID() == ConstantFPVal;
334 //===----------------------------------------------------------------------===//
335 /// All zero aggregate value
337 class ConstantAggregateZero final : public ConstantData {
338 friend class Constant;
340 explicit ConstantAggregateZero(Type *Ty)
341 : ConstantData(Ty, ConstantAggregateZeroVal) {}
343 void destroyConstantImpl();
346 ConstantAggregateZero(const ConstantAggregateZero &) = delete;
348 static ConstantAggregateZero *get(Type *Ty);
350 /// If this CAZ has array or vector type, return a zero with the right element
352 Constant *getSequentialElement() const;
354 /// If this CAZ has struct type, return a zero with the right element type for
355 /// the specified element.
356 Constant *getStructElement(unsigned Elt) const;
358 /// Return a zero of the right value for the specified GEP index if we can,
359 /// otherwise return null (e.g. if C is a ConstantExpr).
360 Constant *getElementValue(Constant *C) const;
362 /// Return a zero of the right value for the specified GEP index.
363 Constant *getElementValue(unsigned Idx) const;
365 /// Return the number of elements in the array, vector, or struct.
366 unsigned getNumElements() const;
368 /// Methods for support type inquiry through isa, cast, and dyn_cast:
370 static bool classof(const Value *V) {
371 return V->getValueID() == ConstantAggregateZeroVal;
375 /// Base class for aggregate constants (with operands).
377 /// These constants are aggregates of other constants, which are stored as
380 /// Subclasses are \a ConstantStruct, \a ConstantArray, and \a
383 /// \note Some subclasses of \a ConstantData are semantically aggregates --
384 /// such as \a ConstantDataArray -- but are not subclasses of this because they
386 class ConstantAggregate : public Constant {
388 ConstantAggregate(CompositeType *T, ValueTy VT, ArrayRef<Constant *> V);
391 /// Transparently provide more efficient getOperand methods.
392 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
394 /// Methods for support type inquiry through isa, cast, and dyn_cast:
395 static bool classof(const Value *V) {
396 return V->getValueID() >= ConstantAggregateFirstVal &&
397 V->getValueID() <= ConstantAggregateLastVal;
402 struct OperandTraits<ConstantAggregate>
403 : public VariadicOperandTraits<ConstantAggregate> {};
405 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantAggregate, Constant)
407 //===----------------------------------------------------------------------===//
408 /// ConstantArray - Constant Array Declarations
410 class ConstantArray final : public ConstantAggregate {
411 friend struct ConstantAggrKeyType<ConstantArray>;
412 friend class Constant;
414 ConstantArray(ArrayType *T, ArrayRef<Constant *> Val);
416 void destroyConstantImpl();
417 Value *handleOperandChangeImpl(Value *From, Value *To);
420 // ConstantArray accessors
421 static Constant *get(ArrayType *T, ArrayRef<Constant*> V);
424 static Constant *getImpl(ArrayType *T, ArrayRef<Constant *> V);
427 /// Specialize the getType() method to always return an ArrayType,
428 /// which reduces the amount of casting needed in parts of the compiler.
429 inline ArrayType *getType() const {
430 return cast<ArrayType>(Value::getType());
433 /// Methods for support type inquiry through isa, cast, and dyn_cast:
434 static bool classof(const Value *V) {
435 return V->getValueID() == ConstantArrayVal;
439 //===----------------------------------------------------------------------===//
440 // Constant Struct Declarations
442 class ConstantStruct final : public ConstantAggregate {
443 friend struct ConstantAggrKeyType<ConstantStruct>;
444 friend class Constant;
446 ConstantStruct(StructType *T, ArrayRef<Constant *> Val);
448 void destroyConstantImpl();
449 Value *handleOperandChangeImpl(Value *From, Value *To);
452 // ConstantStruct accessors
453 static Constant *get(StructType *T, ArrayRef<Constant*> V);
455 template <typename... Csts>
456 static typename std::enable_if<are_base_of<Constant, Csts...>::value,
458 get(StructType *T, Csts *... Vs) {
459 SmallVector<Constant *, 8> Values({Vs...});
460 return get(T, Values);
463 /// Return an anonymous struct that has the specified elements.
464 /// If the struct is possibly empty, then you must specify a context.
465 static Constant *getAnon(ArrayRef<Constant*> V, bool Packed = false) {
466 return get(getTypeForElements(V, Packed), V);
468 static Constant *getAnon(LLVMContext &Ctx,
469 ArrayRef<Constant*> V, bool Packed = false) {
470 return get(getTypeForElements(Ctx, V, Packed), V);
473 /// Return an anonymous struct type to use for a constant with the specified
474 /// set of elements. The list must not be empty.
475 static StructType *getTypeForElements(ArrayRef<Constant*> V,
476 bool Packed = false);
477 /// This version of the method allows an empty list.
478 static StructType *getTypeForElements(LLVMContext &Ctx,
479 ArrayRef<Constant*> V,
480 bool Packed = false);
482 /// Specialization - reduce amount of casting.
483 inline StructType *getType() const {
484 return cast<StructType>(Value::getType());
487 /// Methods for support type inquiry through isa, cast, and dyn_cast:
488 static bool classof(const Value *V) {
489 return V->getValueID() == ConstantStructVal;
493 //===----------------------------------------------------------------------===//
494 /// Constant Vector Declarations
496 class ConstantVector final : public ConstantAggregate {
497 friend struct ConstantAggrKeyType<ConstantVector>;
498 friend class Constant;
500 ConstantVector(VectorType *T, ArrayRef<Constant *> Val);
502 void destroyConstantImpl();
503 Value *handleOperandChangeImpl(Value *From, Value *To);
506 // ConstantVector accessors
507 static Constant *get(ArrayRef<Constant*> V);
510 static Constant *getImpl(ArrayRef<Constant *> V);
513 /// Return a ConstantVector with the specified constant in each element.
514 static Constant *getSplat(unsigned NumElts, Constant *Elt);
516 /// Specialize the getType() method to always return a VectorType,
517 /// which reduces the amount of casting needed in parts of the compiler.
518 inline VectorType *getType() const {
519 return cast<VectorType>(Value::getType());
522 /// If this is a splat constant, meaning that all of the elements have the
523 /// same value, return that value. Otherwise return NULL.
524 Constant *getSplatValue() const;
526 /// Methods for support type inquiry through isa, cast, and dyn_cast:
527 static bool classof(const Value *V) {
528 return V->getValueID() == ConstantVectorVal;
532 //===----------------------------------------------------------------------===//
533 /// A constant pointer value that points to null
535 class ConstantPointerNull final : public ConstantData {
536 friend class Constant;
538 explicit ConstantPointerNull(PointerType *T)
539 : ConstantData(T, Value::ConstantPointerNullVal) {}
541 void destroyConstantImpl();
544 ConstantPointerNull(const ConstantPointerNull &) = delete;
546 /// Static factory methods - Return objects of the specified value
547 static ConstantPointerNull *get(PointerType *T);
549 /// Specialize the getType() method to always return an PointerType,
550 /// which reduces the amount of casting needed in parts of the compiler.
551 inline PointerType *getType() const {
552 return cast<PointerType>(Value::getType());
555 /// Methods for support type inquiry through isa, cast, and dyn_cast:
556 static bool classof(const Value *V) {
557 return V->getValueID() == ConstantPointerNullVal;
561 //===----------------------------------------------------------------------===//
562 /// ConstantDataSequential - A vector or array constant whose element type is a
563 /// simple 1/2/4/8-byte integer or float/double, and whose elements are just
564 /// simple data values (i.e. ConstantInt/ConstantFP). This Constant node has no
565 /// operands because it stores all of the elements of the constant as densely
566 /// packed data, instead of as Value*'s.
568 /// This is the common base class of ConstantDataArray and ConstantDataVector.
570 class ConstantDataSequential : public ConstantData {
571 friend class LLVMContextImpl;
572 friend class Constant;
574 /// A pointer to the bytes underlying this constant (which is owned by the
575 /// uniquing StringMap).
576 const char *DataElements;
578 /// This forms a link list of ConstantDataSequential nodes that have
579 /// the same value but different type. For example, 0,0,0,1 could be a 4
580 /// element array of i8, or a 1-element array of i32. They'll both end up in
581 /// the same StringMap bucket, linked up.
582 ConstantDataSequential *Next;
584 void destroyConstantImpl();
587 explicit ConstantDataSequential(Type *ty, ValueTy VT, const char *Data)
588 : ConstantData(ty, VT), DataElements(Data), Next(nullptr) {}
589 ~ConstantDataSequential() { delete Next; }
591 static Constant *getImpl(StringRef Bytes, Type *Ty);
594 ConstantDataSequential(const ConstantDataSequential &) = delete;
596 /// Return true if a ConstantDataSequential can be formed with a vector or
597 /// array of the specified element type.
598 /// ConstantDataArray only works with normal float and int types that are
599 /// stored densely in memory, not with things like i42 or x86_f80.
600 static bool isElementTypeCompatible(Type *Ty);
602 /// If this is a sequential container of integers (of any size), return the
603 /// specified element in the low bits of a uint64_t.
604 uint64_t getElementAsInteger(unsigned i) const;
606 /// If this is a sequential container of integers (of any size), return the
607 /// specified element as an APInt.
608 APInt getElementAsAPInt(unsigned i) const;
610 /// If this is a sequential container of floating point type, return the
611 /// specified element as an APFloat.
612 APFloat getElementAsAPFloat(unsigned i) const;
614 /// If this is an sequential container of floats, return the specified element
616 float getElementAsFloat(unsigned i) const;
618 /// If this is an sequential container of doubles, return the specified
619 /// element as a double.
620 double getElementAsDouble(unsigned i) const;
622 /// Return a Constant for a specified index's element.
623 /// Note that this has to compute a new constant to return, so it isn't as
624 /// efficient as getElementAsInteger/Float/Double.
625 Constant *getElementAsConstant(unsigned i) const;
627 /// Specialize the getType() method to always return a SequentialType, which
628 /// reduces the amount of casting needed in parts of the compiler.
629 inline SequentialType *getType() const {
630 return cast<SequentialType>(Value::getType());
633 /// Return the element type of the array/vector.
634 Type *getElementType() const;
636 /// Return the number of elements in the array or vector.
637 unsigned getNumElements() const;
639 /// Return the size (in bytes) of each element in the array/vector.
640 /// The size of the elements is known to be a multiple of one byte.
641 uint64_t getElementByteSize() const;
643 /// This method returns true if this is an array of \p CharSize integers.
644 bool isString(unsigned CharSize = 8) const;
646 /// This method returns true if the array "isString", ends with a null byte,
647 /// and does not contains any other null bytes.
648 bool isCString() const;
650 /// If this array is isString(), then this method returns the array as a
651 /// StringRef. Otherwise, it asserts out.
652 StringRef getAsString() const {
653 assert(isString() && "Not a string");
654 return getRawDataValues();
657 /// If this array is isCString(), then this method returns the array (without
658 /// the trailing null byte) as a StringRef. Otherwise, it asserts out.
659 StringRef getAsCString() const {
660 assert(isCString() && "Isn't a C string");
661 StringRef Str = getAsString();
662 return Str.substr(0, Str.size()-1);
665 /// Return the raw, underlying, bytes of this data. Note that this is an
666 /// extremely tricky thing to work with, as it exposes the host endianness of
667 /// the data elements.
668 StringRef getRawDataValues() const;
670 /// Methods for support type inquiry through isa, cast, and dyn_cast:
671 static bool classof(const Value *V) {
672 return V->getValueID() == ConstantDataArrayVal ||
673 V->getValueID() == ConstantDataVectorVal;
677 const char *getElementPointer(unsigned Elt) const;
680 //===----------------------------------------------------------------------===//
681 /// An array constant whose element type is a simple 1/2/4/8-byte integer or
682 /// float/double, and whose elements are just simple data values
683 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it
684 /// stores all of the elements of the constant as densely packed data, instead
686 class ConstantDataArray final : public ConstantDataSequential {
687 friend class ConstantDataSequential;
689 explicit ConstantDataArray(Type *ty, const char *Data)
690 : ConstantDataSequential(ty, ConstantDataArrayVal, Data) {}
693 ConstantDataArray(const ConstantDataArray &) = delete;
695 /// get() constructor - Return a constant with array type with an element
696 /// count and element type matching the ArrayRef passed in. Note that this
697 /// can return a ConstantAggregateZero object.
698 template <typename ElementTy>
699 static Constant *get(LLVMContext &Context, ArrayRef<ElementTy> Elts) {
700 const char *Data = reinterpret_cast<const char *>(Elts.data());
701 return getRaw(StringRef(Data, Elts.size() * sizeof(ElementTy)), Elts.size(),
702 Type::getScalarTy<ElementTy>(Context));
705 /// get() constructor - ArrayTy needs to be compatible with
706 /// ArrayRef<ElementTy>. Calls get(LLVMContext, ArrayRef<ElementTy>).
707 template <typename ArrayTy>
708 static Constant *get(LLVMContext &Context, ArrayTy &Elts) {
709 return ConstantDataArray::get(Context, makeArrayRef(Elts));
712 /// get() constructor - Return a constant with array type with an element
713 /// count and element type matching the NumElements and ElementTy parameters
714 /// passed in. Note that this can return a ConstantAggregateZero object.
715 /// ElementTy needs to be one of i8/i16/i32/i64/float/double. Data is the
716 /// buffer containing the elements. Be careful to make sure Data uses the
717 /// right endianness, the buffer will be used as-is.
718 static Constant *getRaw(StringRef Data, uint64_t NumElements, Type *ElementTy) {
719 Type *Ty = ArrayType::get(ElementTy, NumElements);
720 return getImpl(Data, Ty);
723 /// getFP() constructors - Return a constant with array type with an element
724 /// count and element type of float with precision matching the number of
725 /// bits in the ArrayRef passed in. (i.e. half for 16bits, float for 32bits,
726 /// double for 64bits) Note that this can return a ConstantAggregateZero
728 static Constant *getFP(LLVMContext &Context, ArrayRef<uint16_t> Elts);
729 static Constant *getFP(LLVMContext &Context, ArrayRef<uint32_t> Elts);
730 static Constant *getFP(LLVMContext &Context, ArrayRef<uint64_t> Elts);
732 /// This method constructs a CDS and initializes it with a text string.
733 /// The default behavior (AddNull==true) causes a null terminator to
734 /// be placed at the end of the array (increasing the length of the string by
735 /// one more than the StringRef would normally indicate. Pass AddNull=false
736 /// to disable this behavior.
737 static Constant *getString(LLVMContext &Context, StringRef Initializer,
738 bool AddNull = true);
740 /// Specialize the getType() method to always return an ArrayType,
741 /// which reduces the amount of casting needed in parts of the compiler.
742 inline ArrayType *getType() const {
743 return cast<ArrayType>(Value::getType());
746 /// Methods for support type inquiry through isa, cast, and dyn_cast:
747 static bool classof(const Value *V) {
748 return V->getValueID() == ConstantDataArrayVal;
752 //===----------------------------------------------------------------------===//
753 /// A vector constant whose element type is a simple 1/2/4/8-byte integer or
754 /// float/double, and whose elements are just simple data values
755 /// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it
756 /// stores all of the elements of the constant as densely packed data, instead
758 class ConstantDataVector final : public ConstantDataSequential {
759 friend class ConstantDataSequential;
761 explicit ConstantDataVector(Type *ty, const char *Data)
762 : ConstantDataSequential(ty, ConstantDataVectorVal, Data) {}
765 ConstantDataVector(const ConstantDataVector &) = delete;
767 /// get() constructors - Return a constant with vector type with an element
768 /// count and element type matching the ArrayRef passed in. Note that this
769 /// can return a ConstantAggregateZero object.
770 static Constant *get(LLVMContext &Context, ArrayRef<uint8_t> Elts);
771 static Constant *get(LLVMContext &Context, ArrayRef<uint16_t> Elts);
772 static Constant *get(LLVMContext &Context, ArrayRef<uint32_t> Elts);
773 static Constant *get(LLVMContext &Context, ArrayRef<uint64_t> Elts);
774 static Constant *get(LLVMContext &Context, ArrayRef<float> Elts);
775 static Constant *get(LLVMContext &Context, ArrayRef<double> Elts);
777 /// getFP() constructors - Return a constant with vector type with an element
778 /// count and element type of float with the precision matching the number of
779 /// bits in the ArrayRef passed in. (i.e. half for 16bits, float for 32bits,
780 /// double for 64bits) Note that this can return a ConstantAggregateZero
782 static Constant *getFP(LLVMContext &Context, ArrayRef<uint16_t> Elts);
783 static Constant *getFP(LLVMContext &Context, ArrayRef<uint32_t> Elts);
784 static Constant *getFP(LLVMContext &Context, ArrayRef<uint64_t> Elts);
786 /// Return a ConstantVector with the specified constant in each element.
787 /// The specified constant has to be a of a compatible type (i8/i16/
788 /// i32/i64/float/double) and must be a ConstantFP or ConstantInt.
789 static Constant *getSplat(unsigned NumElts, Constant *Elt);
791 /// Returns true if this is a splat constant, meaning that all elements have
793 bool isSplat() const;
795 /// If this is a splat constant, meaning that all of the elements have the
796 /// same value, return that value. Otherwise return NULL.
797 Constant *getSplatValue() const;
799 /// Specialize the getType() method to always return a VectorType,
800 /// which reduces the amount of casting needed in parts of the compiler.
801 inline VectorType *getType() const {
802 return cast<VectorType>(Value::getType());
805 /// Methods for support type inquiry through isa, cast, and dyn_cast:
806 static bool classof(const Value *V) {
807 return V->getValueID() == ConstantDataVectorVal;
811 //===----------------------------------------------------------------------===//
812 /// A constant token which is empty
814 class ConstantTokenNone final : public ConstantData {
815 friend class Constant;
817 explicit ConstantTokenNone(LLVMContext &Context)
818 : ConstantData(Type::getTokenTy(Context), ConstantTokenNoneVal) {}
820 void destroyConstantImpl();
823 ConstantTokenNone(const ConstantTokenNone &) = delete;
825 /// Return the ConstantTokenNone.
826 static ConstantTokenNone *get(LLVMContext &Context);
828 /// Methods to support type inquiry through isa, cast, and dyn_cast.
829 static bool classof(const Value *V) {
830 return V->getValueID() == ConstantTokenNoneVal;
834 /// The address of a basic block.
836 class BlockAddress final : public Constant {
837 friend class Constant;
839 BlockAddress(Function *F, BasicBlock *BB);
841 void *operator new(size_t s) { return User::operator new(s, 2); }
843 void destroyConstantImpl();
844 Value *handleOperandChangeImpl(Value *From, Value *To);
847 /// Return a BlockAddress for the specified function and basic block.
848 static BlockAddress *get(Function *F, BasicBlock *BB);
850 /// Return a BlockAddress for the specified basic block. The basic
851 /// block must be embedded into a function.
852 static BlockAddress *get(BasicBlock *BB);
854 /// Lookup an existing \c BlockAddress constant for the given BasicBlock.
856 /// \returns 0 if \c !BB->hasAddressTaken(), otherwise the \c BlockAddress.
857 static BlockAddress *lookup(const BasicBlock *BB);
859 /// Transparently provide more efficient getOperand methods.
860 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
862 Function *getFunction() const { return (Function*)Op<0>().get(); }
863 BasicBlock *getBasicBlock() const { return (BasicBlock*)Op<1>().get(); }
865 /// Methods for support type inquiry through isa, cast, and dyn_cast:
866 static bool classof(const Value *V) {
867 return V->getValueID() == BlockAddressVal;
872 struct OperandTraits<BlockAddress> :
873 public FixedNumOperandTraits<BlockAddress, 2> {
876 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BlockAddress, Value)
878 //===----------------------------------------------------------------------===//
879 /// A constant value that is initialized with an expression using
880 /// other constant values.
882 /// This class uses the standard Instruction opcodes to define the various
883 /// constant expressions. The Opcode field for the ConstantExpr class is
884 /// maintained in the Value::SubclassData field.
885 class ConstantExpr : public Constant {
886 friend struct ConstantExprKeyType;
887 friend class Constant;
889 void destroyConstantImpl();
890 Value *handleOperandChangeImpl(Value *From, Value *To);
893 ConstantExpr(Type *ty, unsigned Opcode, Use *Ops, unsigned NumOps)
894 : Constant(ty, ConstantExprVal, Ops, NumOps) {
895 // Operation type (an Instruction opcode) is stored as the SubclassData.
896 setValueSubclassData(Opcode);
900 // Static methods to construct a ConstantExpr of different kinds. Note that
901 // these methods may return a object that is not an instance of the
902 // ConstantExpr class, because they will attempt to fold the constant
903 // expression into something simpler if possible.
905 /// getAlignOf constant expr - computes the alignment of a type in a target
906 /// independent way (Note: the return type is an i64).
907 static Constant *getAlignOf(Type *Ty);
909 /// getSizeOf constant expr - computes the (alloc) size of a type (in
910 /// address-units, not bits) in a target independent way (Note: the return
913 static Constant *getSizeOf(Type *Ty);
915 /// getOffsetOf constant expr - computes the offset of a struct field in a
916 /// target independent way (Note: the return type is an i64).
918 static Constant *getOffsetOf(StructType *STy, unsigned FieldNo);
920 /// getOffsetOf constant expr - This is a generalized form of getOffsetOf,
921 /// which supports any aggregate type, and any Constant index.
923 static Constant *getOffsetOf(Type *Ty, Constant *FieldNo);
925 static Constant *getNeg(Constant *C, bool HasNUW = false, bool HasNSW =false);
926 static Constant *getFNeg(Constant *C);
927 static Constant *getNot(Constant *C);
928 static Constant *getAdd(Constant *C1, Constant *C2,
929 bool HasNUW = false, bool HasNSW = false);
930 static Constant *getFAdd(Constant *C1, Constant *C2);
931 static Constant *getSub(Constant *C1, Constant *C2,
932 bool HasNUW = false, bool HasNSW = false);
933 static Constant *getFSub(Constant *C1, Constant *C2);
934 static Constant *getMul(Constant *C1, Constant *C2,
935 bool HasNUW = false, bool HasNSW = false);
936 static Constant *getFMul(Constant *C1, Constant *C2);
937 static Constant *getUDiv(Constant *C1, Constant *C2, bool isExact = false);
938 static Constant *getSDiv(Constant *C1, Constant *C2, bool isExact = false);
939 static Constant *getFDiv(Constant *C1, Constant *C2);
940 static Constant *getURem(Constant *C1, Constant *C2);
941 static Constant *getSRem(Constant *C1, Constant *C2);
942 static Constant *getFRem(Constant *C1, Constant *C2);
943 static Constant *getAnd(Constant *C1, Constant *C2);
944 static Constant *getOr(Constant *C1, Constant *C2);
945 static Constant *getXor(Constant *C1, Constant *C2);
946 static Constant *getShl(Constant *C1, Constant *C2,
947 bool HasNUW = false, bool HasNSW = false);
948 static Constant *getLShr(Constant *C1, Constant *C2, bool isExact = false);
949 static Constant *getAShr(Constant *C1, Constant *C2, bool isExact = false);
950 static Constant *getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced = false);
951 static Constant *getSExt(Constant *C, Type *Ty, bool OnlyIfReduced = false);
952 static Constant *getZExt(Constant *C, Type *Ty, bool OnlyIfReduced = false);
953 static Constant *getFPTrunc(Constant *C, Type *Ty,
954 bool OnlyIfReduced = false);
955 static Constant *getFPExtend(Constant *C, Type *Ty,
956 bool OnlyIfReduced = false);
957 static Constant *getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false);
958 static Constant *getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false);
959 static Constant *getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced = false);
960 static Constant *getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced = false);
961 static Constant *getPtrToInt(Constant *C, Type *Ty,
962 bool OnlyIfReduced = false);
963 static Constant *getIntToPtr(Constant *C, Type *Ty,
964 bool OnlyIfReduced = false);
965 static Constant *getBitCast(Constant *C, Type *Ty,
966 bool OnlyIfReduced = false);
967 static Constant *getAddrSpaceCast(Constant *C, Type *Ty,
968 bool OnlyIfReduced = false);
970 static Constant *getNSWNeg(Constant *C) { return getNeg(C, false, true); }
971 static Constant *getNUWNeg(Constant *C) { return getNeg(C, true, false); }
973 static Constant *getNSWAdd(Constant *C1, Constant *C2) {
974 return getAdd(C1, C2, false, true);
977 static Constant *getNUWAdd(Constant *C1, Constant *C2) {
978 return getAdd(C1, C2, true, false);
981 static Constant *getNSWSub(Constant *C1, Constant *C2) {
982 return getSub(C1, C2, false, true);
985 static Constant *getNUWSub(Constant *C1, Constant *C2) {
986 return getSub(C1, C2, true, false);
989 static Constant *getNSWMul(Constant *C1, Constant *C2) {
990 return getMul(C1, C2, false, true);
993 static Constant *getNUWMul(Constant *C1, Constant *C2) {
994 return getMul(C1, C2, true, false);
997 static Constant *getNSWShl(Constant *C1, Constant *C2) {
998 return getShl(C1, C2, false, true);
1001 static Constant *getNUWShl(Constant *C1, Constant *C2) {
1002 return getShl(C1, C2, true, false);
1005 static Constant *getExactSDiv(Constant *C1, Constant *C2) {
1006 return getSDiv(C1, C2, true);
1009 static Constant *getExactUDiv(Constant *C1, Constant *C2) {
1010 return getUDiv(C1, C2, true);
1013 static Constant *getExactAShr(Constant *C1, Constant *C2) {
1014 return getAShr(C1, C2, true);
1017 static Constant *getExactLShr(Constant *C1, Constant *C2) {
1018 return getLShr(C1, C2, true);
1021 /// Return the identity constant for a binary opcode.
1022 /// The identity constant C is defined as X op C = X and C op X = X for every
1023 /// X when the binary operation is commutative. If the binop is not
1024 /// commutative, callers can acquire the operand 1 identity constant by
1025 /// setting AllowRHSConstant to true. For example, any shift has a zero
1026 /// identity constant for operand 1: X shift 0 = X.
1027 /// Return nullptr if the operator does not have an identity constant.
1028 static Constant *getBinOpIdentity(unsigned Opcode, Type *Ty,
1029 bool AllowRHSConstant = false);
1031 /// Return the absorbing element for the given binary
1032 /// operation, i.e. a constant C such that X op C = C and C op X = C for
1033 /// every X. For example, this returns zero for integer multiplication.
1034 /// It returns null if the operator doesn't have an absorbing element.
1035 static Constant *getBinOpAbsorber(unsigned Opcode, Type *Ty);
1037 /// Transparently provide more efficient getOperand methods.
1038 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
1040 /// Convenience function for getting a Cast operation.
1042 /// \param ops The opcode for the conversion
1043 /// \param C The constant to be converted
1044 /// \param Ty The type to which the constant is converted
1045 /// \param OnlyIfReduced see \a getWithOperands() docs.
1046 static Constant *getCast(unsigned ops, Constant *C, Type *Ty,
1047 bool OnlyIfReduced = false);
1049 // Create a ZExt or BitCast cast constant expression
1050 static Constant *getZExtOrBitCast(
1051 Constant *C, ///< The constant to zext or bitcast
1052 Type *Ty ///< The type to zext or bitcast C to
1055 // Create a SExt or BitCast cast constant expression
1056 static Constant *getSExtOrBitCast(
1057 Constant *C, ///< The constant to sext or bitcast
1058 Type *Ty ///< The type to sext or bitcast C to
1061 // Create a Trunc or BitCast cast constant expression
1062 static Constant *getTruncOrBitCast(
1063 Constant *C, ///< The constant to trunc or bitcast
1064 Type *Ty ///< The type to trunc or bitcast C to
1067 /// Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant
1069 static Constant *getPointerCast(
1070 Constant *C, ///< The pointer value to be casted (operand 0)
1071 Type *Ty ///< The type to which cast should be made
1074 /// Create a BitCast or AddrSpaceCast for a pointer type depending on
1075 /// the address space.
1076 static Constant *getPointerBitCastOrAddrSpaceCast(
1077 Constant *C, ///< The constant to addrspacecast or bitcast
1078 Type *Ty ///< The type to bitcast or addrspacecast C to
1081 /// Create a ZExt, Bitcast or Trunc for integer -> integer casts
1082 static Constant *getIntegerCast(
1083 Constant *C, ///< The integer constant to be casted
1084 Type *Ty, ///< The integer type to cast to
1085 bool isSigned ///< Whether C should be treated as signed or not
1088 /// Create a FPExt, Bitcast or FPTrunc for fp -> fp casts
1089 static Constant *getFPCast(
1090 Constant *C, ///< The integer constant to be casted
1091 Type *Ty ///< The integer type to cast to
1094 /// Return true if this is a convert constant expression
1095 bool isCast() const;
1097 /// Return true if this is a compare constant expression
1098 bool isCompare() const;
1100 /// Return true if this is an insertvalue or extractvalue expression,
1101 /// and the getIndices() method may be used.
1102 bool hasIndices() const;
1104 /// Return true if this is a getelementptr expression and all
1105 /// the index operands are compile-time known integers within the
1106 /// corresponding notional static array extents. Note that this is
1107 /// not equivalant to, a subset of, or a superset of the "inbounds"
1109 bool isGEPWithNoNotionalOverIndexing() const;
1111 /// Select constant expr
1113 /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1114 static Constant *getSelect(Constant *C, Constant *V1, Constant *V2,
1115 Type *OnlyIfReducedTy = nullptr);
1117 /// get - Return a binary or shift operator constant expression,
1118 /// folding if possible.
1120 /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1121 static Constant *get(unsigned Opcode, Constant *C1, Constant *C2,
1122 unsigned Flags = 0, Type *OnlyIfReducedTy = nullptr);
1124 /// Return an ICmp or FCmp comparison operator constant expression.
1126 /// \param OnlyIfReduced see \a getWithOperands() docs.
1127 static Constant *getCompare(unsigned short pred, Constant *C1, Constant *C2,
1128 bool OnlyIfReduced = false);
1130 /// get* - Return some common constants without having to
1131 /// specify the full Instruction::OPCODE identifier.
1133 static Constant *getICmp(unsigned short pred, Constant *LHS, Constant *RHS,
1134 bool OnlyIfReduced = false);
1135 static Constant *getFCmp(unsigned short pred, Constant *LHS, Constant *RHS,
1136 bool OnlyIfReduced = false);
1138 /// Getelementptr form. Value* is only accepted for convenience;
1139 /// all elements must be Constants.
1141 /// \param InRangeIndex the inrange index if present or None.
1142 /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1143 static Constant *getGetElementPtr(Type *Ty, Constant *C,
1144 ArrayRef<Constant *> IdxList,
1145 bool InBounds = false,
1146 Optional<unsigned> InRangeIndex = None,
1147 Type *OnlyIfReducedTy = nullptr) {
1148 return getGetElementPtr(
1149 Ty, C, makeArrayRef((Value * const *)IdxList.data(), IdxList.size()),
1150 InBounds, InRangeIndex, OnlyIfReducedTy);
1152 static Constant *getGetElementPtr(Type *Ty, Constant *C, Constant *Idx,
1153 bool InBounds = false,
1154 Optional<unsigned> InRangeIndex = None,
1155 Type *OnlyIfReducedTy = nullptr) {
1156 // This form of the function only exists to avoid ambiguous overload
1157 // warnings about whether to convert Idx to ArrayRef<Constant *> or
1158 // ArrayRef<Value *>.
1159 return getGetElementPtr(Ty, C, cast<Value>(Idx), InBounds, InRangeIndex,
1162 static Constant *getGetElementPtr(Type *Ty, Constant *C,
1163 ArrayRef<Value *> IdxList,
1164 bool InBounds = false,
1165 Optional<unsigned> InRangeIndex = None,
1166 Type *OnlyIfReducedTy = nullptr);
1168 /// Create an "inbounds" getelementptr. See the documentation for the
1169 /// "inbounds" flag in LangRef.html for details.
1170 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1171 ArrayRef<Constant *> IdxList) {
1172 return getGetElementPtr(Ty, C, IdxList, true);
1174 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1176 // This form of the function only exists to avoid ambiguous overload
1177 // warnings about whether to convert Idx to ArrayRef<Constant *> or
1178 // ArrayRef<Value *>.
1179 return getGetElementPtr(Ty, C, Idx, true);
1181 static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1182 ArrayRef<Value *> IdxList) {
1183 return getGetElementPtr(Ty, C, IdxList, true);
1186 static Constant *getExtractElement(Constant *Vec, Constant *Idx,
1187 Type *OnlyIfReducedTy = nullptr);
1188 static Constant *getInsertElement(Constant *Vec, Constant *Elt, Constant *Idx,
1189 Type *OnlyIfReducedTy = nullptr);
1190 static Constant *getShuffleVector(Constant *V1, Constant *V2, Constant *Mask,
1191 Type *OnlyIfReducedTy = nullptr);
1192 static Constant *getExtractValue(Constant *Agg, ArrayRef<unsigned> Idxs,
1193 Type *OnlyIfReducedTy = nullptr);
1194 static Constant *getInsertValue(Constant *Agg, Constant *Val,
1195 ArrayRef<unsigned> Idxs,
1196 Type *OnlyIfReducedTy = nullptr);
1198 /// Return the opcode at the root of this constant expression
1199 unsigned getOpcode() const { return getSubclassDataFromValue(); }
1201 /// Return the ICMP or FCMP predicate value. Assert if this is not an ICMP or
1202 /// FCMP constant expression.
1203 unsigned getPredicate() const;
1205 /// Assert that this is an insertvalue or exactvalue
1206 /// expression and return the list of indices.
1207 ArrayRef<unsigned> getIndices() const;
1209 /// Return a string representation for an opcode.
1210 const char *getOpcodeName() const;
1212 /// Return a constant expression identical to this one, but with the specified
1213 /// operand set to the specified value.
1214 Constant *getWithOperandReplaced(unsigned OpNo, Constant *Op) const;
1216 /// This returns the current constant expression with the operands replaced
1217 /// with the specified values. The specified array must have the same number
1218 /// of operands as our current one.
1219 Constant *getWithOperands(ArrayRef<Constant*> Ops) const {
1220 return getWithOperands(Ops, getType());
1223 /// Get the current expression with the operands replaced.
1225 /// Return the current constant expression with the operands replaced with \c
1226 /// Ops and the type with \c Ty. The new operands must have the same number
1227 /// as the current ones.
1229 /// If \c OnlyIfReduced is \c true, nullptr will be returned unless something
1230 /// gets constant-folded, the type changes, or the expression is otherwise
1231 /// canonicalized. This parameter should almost always be \c false.
1232 Constant *getWithOperands(ArrayRef<Constant *> Ops, Type *Ty,
1233 bool OnlyIfReduced = false,
1234 Type *SrcTy = nullptr) const;
1236 /// Returns an Instruction which implements the same operation as this
1237 /// ConstantExpr. The instruction is not linked to any basic block.
1239 /// A better approach to this could be to have a constructor for Instruction
1240 /// which would take a ConstantExpr parameter, but that would have spread
1241 /// implementation details of ConstantExpr outside of Constants.cpp, which
1242 /// would make it harder to remove ConstantExprs altogether.
1243 Instruction *getAsInstruction();
1245 /// Methods for support type inquiry through isa, cast, and dyn_cast:
1246 static bool classof(const Value *V) {
1247 return V->getValueID() == ConstantExprVal;
1251 // Shadow Value::setValueSubclassData with a private forwarding method so that
1252 // subclasses cannot accidentally use it.
1253 void setValueSubclassData(unsigned short D) {
1254 Value::setValueSubclassData(D);
1259 struct OperandTraits<ConstantExpr> :
1260 public VariadicOperandTraits<ConstantExpr, 1> {
1263 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantExpr, Constant)
1265 //===----------------------------------------------------------------------===//
1266 /// 'undef' values are things that do not have specified contents.
1267 /// These are used for a variety of purposes, including global variable
1268 /// initializers and operands to instructions. 'undef' values can occur with
1269 /// any first-class type.
1271 /// Undef values aren't exactly constants; if they have multiple uses, they
1272 /// can appear to have different bit patterns at each use. See
1273 /// LangRef.html#undefvalues for details.
1275 class UndefValue final : public ConstantData {
1276 friend class Constant;
1278 explicit UndefValue(Type *T) : ConstantData(T, UndefValueVal) {}
1280 void destroyConstantImpl();
1283 UndefValue(const UndefValue &) = delete;
1285 /// Static factory methods - Return an 'undef' object of the specified type.
1286 static UndefValue *get(Type *T);
1288 /// If this Undef has array or vector type, return a undef with the right
1290 UndefValue *getSequentialElement() const;
1292 /// If this undef has struct type, return a undef with the right element type
1293 /// for the specified element.
1294 UndefValue *getStructElement(unsigned Elt) const;
1296 /// Return an undef of the right value for the specified GEP index if we can,
1297 /// otherwise return null (e.g. if C is a ConstantExpr).
1298 UndefValue *getElementValue(Constant *C) const;
1300 /// Return an undef of the right value for the specified GEP index.
1301 UndefValue *getElementValue(unsigned Idx) const;
1303 /// Return the number of elements in the array, vector, or struct.
1304 unsigned getNumElements() const;
1306 /// Methods for support type inquiry through isa, cast, and dyn_cast:
1307 static bool classof(const Value *V) {
1308 return V->getValueID() == UndefValueVal;
1312 } // end namespace llvm
1314 #endif // LLVM_IR_CONSTANTS_H