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//===-- llvm/Constants.h - Constant class subclass definitions --*- C++ -*-===//
2
//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4
// See https://llvm.org/LICENSE.txt for license information.
5
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6
//
7
//===----------------------------------------------------------------------===//
8
//
9
/// @file
10
/// This file contains the declarations for the subclasses of Constant,
11
/// which represent the different flavors of constant values that live in LLVM.
12
/// Note that Constants are immutable (once created they never change) and are
13
/// fully shared by structural equivalence.  This means that two structurally
14
/// equivalent constants will always have the same address.  Constants are
15
/// created on demand as needed and never deleted: thus clients don't have to
16
/// worry about the lifetime of the objects.
17
//
18
//===----------------------------------------------------------------------===//
19
 
20
#ifndef LLVM_IR_CONSTANTS_H
21
#define LLVM_IR_CONSTANTS_H
22
 
23
#include "llvm/ADT/APFloat.h"
24
#include "llvm/ADT/APInt.h"
25
#include "llvm/ADT/ArrayRef.h"
26
#include "llvm/ADT/STLExtras.h"
27
#include "llvm/ADT/StringRef.h"
28
#include "llvm/IR/Constant.h"
29
#include "llvm/IR/DerivedTypes.h"
30
#include "llvm/IR/OperandTraits.h"
31
#include "llvm/IR/User.h"
32
#include "llvm/IR/Value.h"
33
#include "llvm/Support/Casting.h"
34
#include "llvm/Support/Compiler.h"
35
#include "llvm/Support/ErrorHandling.h"
36
#include <cassert>
37
#include <cstddef>
38
#include <cstdint>
39
#include <optional>
40
 
41
namespace llvm {
42
 
43
template <class ConstantClass> struct ConstantAggrKeyType;
44
 
45
/// Base class for constants with no operands.
46
///
47
/// These constants have no operands; they represent their data directly.
48
/// Since they can be in use by unrelated modules (and are never based on
49
/// GlobalValues), it never makes sense to RAUW them.
50
class ConstantData : public Constant {
51
  friend class Constant;
52
 
53
  Value *handleOperandChangeImpl(Value *From, Value *To) {
54
    llvm_unreachable("Constant data does not have operands!");
55
  }
56
 
57
protected:
58
  explicit ConstantData(Type *Ty, ValueTy VT) : Constant(Ty, VT, nullptr, 0) {}
59
 
60
  void *operator new(size_t S) { return User::operator new(S, 0); }
61
 
62
public:
63
  void operator delete(void *Ptr) { User::operator delete(Ptr); }
64
 
65
  ConstantData(const ConstantData &) = delete;
66
 
67
  /// Methods to support type inquiry through isa, cast, and dyn_cast.
68
  static bool classof(const Value *V) {
69
    return V->getValueID() >= ConstantDataFirstVal &&
70
           V->getValueID() <= ConstantDataLastVal;
71
  }
72
};
73
 
74
//===----------------------------------------------------------------------===//
75
/// This is the shared class of boolean and integer constants. This class
76
/// represents both boolean and integral constants.
77
/// Class for constant integers.
78
class ConstantInt final : public ConstantData {
79
  friend class Constant;
80
 
81
  APInt Val;
82
 
83
  ConstantInt(IntegerType *Ty, const APInt &V);
84
 
85
  void destroyConstantImpl();
86
 
87
public:
88
  ConstantInt(const ConstantInt &) = delete;
89
 
90
  static ConstantInt *getTrue(LLVMContext &Context);
91
  static ConstantInt *getFalse(LLVMContext &Context);
92
  static ConstantInt *getBool(LLVMContext &Context, bool V);
93
  static Constant *getTrue(Type *Ty);
94
  static Constant *getFalse(Type *Ty);
95
  static Constant *getBool(Type *Ty, bool V);
96
 
97
  /// If Ty is a vector type, return a Constant with a splat of the given
98
  /// value. Otherwise return a ConstantInt for the given value.
99
  static Constant *get(Type *Ty, uint64_t V, bool IsSigned = false);
100
 
101
  /// Return a ConstantInt with the specified integer value for the specified
102
  /// type. If the type is wider than 64 bits, the value will be zero-extended
103
  /// to fit the type, unless IsSigned is true, in which case the value will
104
  /// be interpreted as a 64-bit signed integer and sign-extended to fit
105
  /// the type.
106
  /// Get a ConstantInt for a specific value.
107
  static ConstantInt *get(IntegerType *Ty, uint64_t V, bool IsSigned = false);
108
 
109
  /// Return a ConstantInt with the specified value for the specified type. The
110
  /// value V will be canonicalized to a an unsigned APInt. Accessing it with
111
  /// either getSExtValue() or getZExtValue() will yield a correctly sized and
112
  /// signed value for the type Ty.
113
  /// Get a ConstantInt for a specific signed value.
114
  static ConstantInt *getSigned(IntegerType *Ty, int64_t V);
115
  static Constant *getSigned(Type *Ty, int64_t V);
116
 
117
  /// Return a ConstantInt with the specified value and an implied Type. The
118
  /// type is the integer type that corresponds to the bit width of the value.
119
  static ConstantInt *get(LLVMContext &Context, const APInt &V);
120
 
121
  /// Return a ConstantInt constructed from the string strStart with the given
122
  /// radix.
123
  static ConstantInt *get(IntegerType *Ty, StringRef Str, uint8_t Radix);
124
 
125
  /// If Ty is a vector type, return a Constant with a splat of the given
126
  /// value. Otherwise return a ConstantInt for the given value.
127
  static Constant *get(Type *Ty, const APInt &V);
128
 
129
  /// Return the constant as an APInt value reference. This allows clients to
130
  /// obtain a full-precision copy of the value.
131
  /// Return the constant's value.
132
  inline const APInt &getValue() const { return Val; }
133
 
134
  /// getBitWidth - Return the bitwidth of this constant.
135
  unsigned getBitWidth() const { return Val.getBitWidth(); }
136
 
137
  /// Return the constant as a 64-bit unsigned integer value after it
138
  /// has been zero extended as appropriate for the type of this constant. Note
139
  /// that this method can assert if the value does not fit in 64 bits.
140
  /// Return the zero extended value.
141
  inline uint64_t getZExtValue() const { return Val.getZExtValue(); }
142
 
143
  /// Return the constant as a 64-bit integer value after it has been sign
144
  /// extended as appropriate for the type of this constant. Note that
145
  /// this method can assert if the value does not fit in 64 bits.
146
  /// Return the sign extended value.
147
  inline int64_t getSExtValue() const { return Val.getSExtValue(); }
148
 
149
  /// Return the constant as an llvm::MaybeAlign.
150
  /// Note that this method can assert if the value does not fit in 64 bits or
151
  /// is not a power of two.
152
  inline MaybeAlign getMaybeAlignValue() const {
153
    return MaybeAlign(getZExtValue());
154
  }
155
 
156
  /// Return the constant as an llvm::Align, interpreting `0` as `Align(1)`.
157
  /// Note that this method can assert if the value does not fit in 64 bits or
158
  /// is not a power of two.
159
  inline Align getAlignValue() const {
160
    return getMaybeAlignValue().valueOrOne();
161
  }
162
 
163
  /// A helper method that can be used to determine if the constant contained
164
  /// within is equal to a constant.  This only works for very small values,
165
  /// because this is all that can be represented with all types.
166
  /// Determine if this constant's value is same as an unsigned char.
167
  bool equalsInt(uint64_t V) const { return Val == V; }
168
 
169
  /// getType - Specialize the getType() method to always return an IntegerType,
170
  /// which reduces the amount of casting needed in parts of the compiler.
171
  ///
172
  inline IntegerType *getType() const {
173
    return cast<IntegerType>(Value::getType());
174
  }
175
 
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);
187
 
188
  bool isNegative() const { return Val.isNegative(); }
189
 
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 { return Val.isZero(); }
194
 
195
  /// This is just a convenience method to make client code smaller for a
196
  /// common case. It also correctly performs the comparison without the
197
  /// potential for an assertion from getZExtValue().
198
  /// Determine if the value is one.
199
  bool isOne() const { return Val.isOne(); }
200
 
201
  /// This function will return true iff every bit in this constant is set
202
  /// to true.
203
  /// @returns true iff this constant's bits are all set to true.
204
  /// Determine if the value is all ones.
205
  bool isMinusOne() const { return Val.isAllOnes(); }
206
 
207
  /// This function will return true iff this constant represents the largest
208
  /// value that may be represented by the constant's type.
209
  /// @returns true iff this is the largest value that may be represented
210
  /// by this type.
211
  /// Determine if the value is maximal.
212
  bool isMaxValue(bool IsSigned) const {
213
    if (IsSigned)
214
      return Val.isMaxSignedValue();
215
    else
216
      return Val.isMaxValue();
217
  }
218
 
219
  /// This function will return true iff this constant represents the smallest
220
  /// value that may be represented by this constant's type.
221
  /// @returns true if this is the smallest value that may be represented by
222
  /// this type.
223
  /// Determine if the value is minimal.
224
  bool isMinValue(bool IsSigned) const {
225
    if (IsSigned)
226
      return Val.isMinSignedValue();
227
    else
228
      return Val.isMinValue();
229
  }
230
 
231
  /// This function will return true iff this constant represents a value with
232
  /// active bits bigger than 64 bits or a value greater than the given uint64_t
233
  /// value.
234
  /// @returns true iff this constant is greater or equal to the given number.
235
  /// Determine if the value is greater or equal to the given number.
236
  bool uge(uint64_t Num) const { return Val.uge(Num); }
237
 
238
  /// getLimitedValue - If the value is smaller than the specified limit,
239
  /// return it, otherwise return the limit value.  This causes the value
240
  /// to saturate to the limit.
241
  /// @returns the min of the value of the constant and the specified value
242
  /// Get the constant's value with a saturation limit
243
  uint64_t getLimitedValue(uint64_t Limit = ~0ULL) const {
244
    return Val.getLimitedValue(Limit);
245
  }
246
 
247
  /// Methods to support type inquiry through isa, cast, and dyn_cast.
248
  static bool classof(const Value *V) {
249
    return V->getValueID() == ConstantIntVal;
250
  }
251
};
252
 
253
//===----------------------------------------------------------------------===//
254
/// ConstantFP - Floating Point Values [float, double]
255
///
256
class ConstantFP final : public ConstantData {
257
  friend class Constant;
258
 
259
  APFloat Val;
260
 
261
  ConstantFP(Type *Ty, const APFloat &V);
262
 
263
  void destroyConstantImpl();
264
 
265
public:
266
  ConstantFP(const ConstantFP &) = delete;
267
 
268
  /// Floating point negation must be implemented with f(x) = -0.0 - x. This
269
  /// method returns the negative zero constant for floating point or vector
270
  /// floating point types; for all other types, it returns the null value.
271
  static Constant *getZeroValueForNegation(Type *Ty);
272
 
273
  /// This returns a ConstantFP, or a vector containing a splat of a ConstantFP,
274
  /// for the specified value in the specified type. This should only be used
275
  /// for simple constant values like 2.0/1.0 etc, that are known-valid both as
276
  /// host double and as the target format.
277
  static Constant *get(Type *Ty, double V);
278
 
279
  /// If Ty is a vector type, return a Constant with a splat of the given
280
  /// value. Otherwise return a ConstantFP for the given value.
281
  static Constant *get(Type *Ty, const APFloat &V);
282
 
283
  static Constant *get(Type *Ty, StringRef Str);
284
  static ConstantFP *get(LLVMContext &Context, const APFloat &V);
285
  static Constant *getNaN(Type *Ty, bool Negative = false,
286
                          uint64_t Payload = 0);
287
  static Constant *getQNaN(Type *Ty, bool Negative = false,
288
                           APInt *Payload = nullptr);
289
  static Constant *getSNaN(Type *Ty, bool Negative = false,
290
                           APInt *Payload = nullptr);
291
  static Constant *getZero(Type *Ty, bool Negative = false);
292
  static Constant *getNegativeZero(Type *Ty) { return getZero(Ty, true); }
293
  static Constant *getInfinity(Type *Ty, bool Negative = false);
294
 
295
  /// Return true if Ty is big enough to represent V.
296
  static bool isValueValidForType(Type *Ty, const APFloat &V);
297
  inline const APFloat &getValueAPF() const { return Val; }
298
  inline const APFloat &getValue() const { return Val; }
299
 
300
  /// Return true if the value is positive or negative zero.
301
  bool isZero() const { return Val.isZero(); }
302
 
303
  /// Return true if the sign bit is set.
304
  bool isNegative() const { return Val.isNegative(); }
305
 
306
  /// Return true if the value is infinity
307
  bool isInfinity() const { return Val.isInfinity(); }
308
 
309
  /// Return true if the value is a NaN.
310
  bool isNaN() const { return Val.isNaN(); }
311
 
312
  /// We don't rely on operator== working on double values, as it returns true
313
  /// for things that are clearly not equal, like -0.0 and 0.0.
314
  /// As such, this method can be used to do an exact bit-for-bit comparison of
315
  /// two floating point values.  The version with a double operand is retained
316
  /// because it's so convenient to write isExactlyValue(2.0), but please use
317
  /// it only for simple constants.
318
  bool isExactlyValue(const APFloat &V) const;
319
 
320
  bool isExactlyValue(double V) const {
321
    bool ignored;
322
    APFloat FV(V);
323
    FV.convert(Val.getSemantics(), APFloat::rmNearestTiesToEven, &ignored);
324
    return isExactlyValue(FV);
325
  }
326
 
327
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
328
  static bool classof(const Value *V) {
329
    return V->getValueID() == ConstantFPVal;
330
  }
331
};
332
 
333
//===----------------------------------------------------------------------===//
334
/// All zero aggregate value
335
///
336
class ConstantAggregateZero final : public ConstantData {
337
  friend class Constant;
338
 
339
  explicit ConstantAggregateZero(Type *Ty)
340
      : ConstantData(Ty, ConstantAggregateZeroVal) {}
341
 
342
  void destroyConstantImpl();
343
 
344
public:
345
  ConstantAggregateZero(const ConstantAggregateZero &) = delete;
346
 
347
  static ConstantAggregateZero *get(Type *Ty);
348
 
349
  /// If this CAZ has array or vector type, return a zero with the right element
350
  /// type.
351
  Constant *getSequentialElement() const;
352
 
353
  /// If this CAZ has struct type, return a zero with the right element type for
354
  /// the specified element.
355
  Constant *getStructElement(unsigned Elt) const;
356
 
357
  /// Return a zero of the right value for the specified GEP index if we can,
358
  /// otherwise return null (e.g. if C is a ConstantExpr).
359
  Constant *getElementValue(Constant *C) const;
360
 
361
  /// Return a zero of the right value for the specified GEP index.
362
  Constant *getElementValue(unsigned Idx) const;
363
 
364
  /// Return the number of elements in the array, vector, or struct.
365
  ElementCount getElementCount() const;
366
 
367
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
368
  ///
369
  static bool classof(const Value *V) {
370
    return V->getValueID() == ConstantAggregateZeroVal;
371
  }
372
};
373
 
374
/// Base class for aggregate constants (with operands).
375
///
376
/// These constants are aggregates of other constants, which are stored as
377
/// operands.
378
///
379
/// Subclasses are \a ConstantStruct, \a ConstantArray, and \a
380
/// ConstantVector.
381
///
382
/// \note Some subclasses of \a ConstantData are semantically aggregates --
383
/// such as \a ConstantDataArray -- but are not subclasses of this because they
384
/// use operands.
385
class ConstantAggregate : public Constant {
386
protected:
387
  ConstantAggregate(Type *T, ValueTy VT, ArrayRef<Constant *> V);
388
 
389
public:
390
  /// Transparently provide more efficient getOperand methods.
391
  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
392
 
393
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
394
  static bool classof(const Value *V) {
395
    return V->getValueID() >= ConstantAggregateFirstVal &&
396
           V->getValueID() <= ConstantAggregateLastVal;
397
  }
398
};
399
 
400
template <>
401
struct OperandTraits<ConstantAggregate>
402
    : public VariadicOperandTraits<ConstantAggregate> {};
403
 
404
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantAggregate, Constant)
405
 
406
//===----------------------------------------------------------------------===//
407
/// ConstantArray - Constant Array Declarations
408
///
409
class ConstantArray final : public ConstantAggregate {
410
  friend struct ConstantAggrKeyType<ConstantArray>;
411
  friend class Constant;
412
 
413
  ConstantArray(ArrayType *T, ArrayRef<Constant *> Val);
414
 
415
  void destroyConstantImpl();
416
  Value *handleOperandChangeImpl(Value *From, Value *To);
417
 
418
public:
419
  // ConstantArray accessors
420
  static Constant *get(ArrayType *T, ArrayRef<Constant *> V);
421
 
422
private:
423
  static Constant *getImpl(ArrayType *T, ArrayRef<Constant *> V);
424
 
425
public:
426
  /// Specialize the getType() method to always return an ArrayType,
427
  /// which reduces the amount of casting needed in parts of the compiler.
428
  inline ArrayType *getType() const {
429
    return cast<ArrayType>(Value::getType());
430
  }
431
 
432
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
433
  static bool classof(const Value *V) {
434
    return V->getValueID() == ConstantArrayVal;
435
  }
436
};
437
 
438
//===----------------------------------------------------------------------===//
439
// Constant Struct Declarations
440
//
441
class ConstantStruct final : public ConstantAggregate {
442
  friend struct ConstantAggrKeyType<ConstantStruct>;
443
  friend class Constant;
444
 
445
  ConstantStruct(StructType *T, ArrayRef<Constant *> Val);
446
 
447
  void destroyConstantImpl();
448
  Value *handleOperandChangeImpl(Value *From, Value *To);
449
 
450
public:
451
  // ConstantStruct accessors
452
  static Constant *get(StructType *T, ArrayRef<Constant *> V);
453
 
454
  template <typename... Csts>
455
  static std::enable_if_t<are_base_of<Constant, Csts...>::value, Constant *>
456
  get(StructType *T, Csts *...Vs) {
457
    return get(T, ArrayRef<Constant *>({Vs...}));
458
  }
459
 
460
  /// Return an anonymous struct that has the specified elements.
461
  /// If the struct is possibly empty, then you must specify a context.
462
  static Constant *getAnon(ArrayRef<Constant *> V, bool Packed = false) {
463
    return get(getTypeForElements(V, Packed), V);
464
  }
465
  static Constant *getAnon(LLVMContext &Ctx, ArrayRef<Constant *> V,
466
                           bool Packed = false) {
467
    return get(getTypeForElements(Ctx, V, Packed), V);
468
  }
469
 
470
  /// Return an anonymous struct type to use for a constant with the specified
471
  /// set of elements. The list must not be empty.
472
  static StructType *getTypeForElements(ArrayRef<Constant *> V,
473
                                        bool Packed = false);
474
  /// This version of the method allows an empty list.
475
  static StructType *getTypeForElements(LLVMContext &Ctx,
476
                                        ArrayRef<Constant *> V,
477
                                        bool Packed = false);
478
 
479
  /// Specialization - reduce amount of casting.
480
  inline StructType *getType() const {
481
    return cast<StructType>(Value::getType());
482
  }
483
 
484
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
485
  static bool classof(const Value *V) {
486
    return V->getValueID() == ConstantStructVal;
487
  }
488
};
489
 
490
//===----------------------------------------------------------------------===//
491
/// Constant Vector Declarations
492
///
493
class ConstantVector final : public ConstantAggregate {
494
  friend struct ConstantAggrKeyType<ConstantVector>;
495
  friend class Constant;
496
 
497
  ConstantVector(VectorType *T, ArrayRef<Constant *> Val);
498
 
499
  void destroyConstantImpl();
500
  Value *handleOperandChangeImpl(Value *From, Value *To);
501
 
502
public:
503
  // ConstantVector accessors
504
  static Constant *get(ArrayRef<Constant *> V);
505
 
506
private:
507
  static Constant *getImpl(ArrayRef<Constant *> V);
508
 
509
public:
510
  /// Return a ConstantVector with the specified constant in each element.
511
  /// Note that this might not return an instance of ConstantVector
512
  static Constant *getSplat(ElementCount EC, Constant *Elt);
513
 
514
  /// Specialize the getType() method to always return a FixedVectorType,
515
  /// which reduces the amount of casting needed in parts of the compiler.
516
  inline FixedVectorType *getType() const {
517
    return cast<FixedVectorType>(Value::getType());
518
  }
519
 
520
  /// If all elements of the vector constant have the same value, return that
521
  /// value. Otherwise, return nullptr. Ignore undefined elements by setting
522
  /// AllowUndefs to true.
523
  Constant *getSplatValue(bool AllowUndefs = false) const;
524
 
525
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
526
  static bool classof(const Value *V) {
527
    return V->getValueID() == ConstantVectorVal;
528
  }
529
};
530
 
531
//===----------------------------------------------------------------------===//
532
/// A constant pointer value that points to null
533
///
534
class ConstantPointerNull final : public ConstantData {
535
  friend class Constant;
536
 
537
  explicit ConstantPointerNull(PointerType *T)
538
      : ConstantData(T, Value::ConstantPointerNullVal) {}
539
 
540
  void destroyConstantImpl();
541
 
542
public:
543
  ConstantPointerNull(const ConstantPointerNull &) = delete;
544
 
545
  /// Static factory methods - Return objects of the specified value
546
  static ConstantPointerNull *get(PointerType *T);
547
 
548
  /// Specialize the getType() method to always return an PointerType,
549
  /// which reduces the amount of casting needed in parts of the compiler.
550
  inline PointerType *getType() const {
551
    return cast<PointerType>(Value::getType());
552
  }
553
 
554
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
555
  static bool classof(const Value *V) {
556
    return V->getValueID() == ConstantPointerNullVal;
557
  }
558
};
559
 
560
//===----------------------------------------------------------------------===//
561
/// ConstantDataSequential - A vector or array constant whose element type is a
562
/// simple 1/2/4/8-byte integer or half/bfloat/float/double, and whose elements
563
/// are just simple data values (i.e. ConstantInt/ConstantFP).  This Constant
564
/// node has no operands because it stores all of the elements of the constant
565
/// as densely packed data, instead of as Value*'s.
566
///
567
/// This is the common base class of ConstantDataArray and ConstantDataVector.
568
///
569
class ConstantDataSequential : public ConstantData {
570
  friend class LLVMContextImpl;
571
  friend class Constant;
572
 
573
  /// A pointer to the bytes underlying this constant (which is owned by the
574
  /// uniquing StringMap).
575
  const char *DataElements;
576
 
577
  /// This forms a link list of ConstantDataSequential nodes that have
578
  /// the same value but different type.  For example, 0,0,0,1 could be a 4
579
  /// element array of i8, or a 1-element array of i32.  They'll both end up in
580
  /// the same StringMap bucket, linked up.
581
  std::unique_ptr<ConstantDataSequential> Next;
582
 
583
  void destroyConstantImpl();
584
 
585
protected:
586
  explicit ConstantDataSequential(Type *ty, ValueTy VT, const char *Data)
587
      : ConstantData(ty, VT), DataElements(Data) {}
588
 
589
  static Constant *getImpl(StringRef Bytes, Type *Ty);
590
 
591
public:
592
  ConstantDataSequential(const ConstantDataSequential &) = delete;
593
 
594
  /// Return true if a ConstantDataSequential can be formed with a vector or
595
  /// array of the specified element type.
596
  /// ConstantDataArray only works with normal float and int types that are
597
  /// stored densely in memory, not with things like i42 or x86_f80.
598
  static bool isElementTypeCompatible(Type *Ty);
599
 
600
  /// If this is a sequential container of integers (of any size), return the
601
  /// specified element in the low bits of a uint64_t.
602
  uint64_t getElementAsInteger(unsigned i) const;
603
 
604
  /// If this is a sequential container of integers (of any size), return the
605
  /// specified element as an APInt.
606
  APInt getElementAsAPInt(unsigned i) const;
607
 
608
  /// If this is a sequential container of floating point type, return the
609
  /// specified element as an APFloat.
610
  APFloat getElementAsAPFloat(unsigned i) const;
611
 
612
  /// If this is an sequential container of floats, return the specified element
613
  /// as a float.
614
  float getElementAsFloat(unsigned i) const;
615
 
616
  /// If this is an sequential container of doubles, return the specified
617
  /// element as a double.
618
  double getElementAsDouble(unsigned i) const;
619
 
620
  /// Return a Constant for a specified index's element.
621
  /// Note that this has to compute a new constant to return, so it isn't as
622
  /// efficient as getElementAsInteger/Float/Double.
623
  Constant *getElementAsConstant(unsigned i) const;
624
 
625
  /// Return the element type of the array/vector.
626
  Type *getElementType() const;
627
 
628
  /// Return the number of elements in the array or vector.
629
  unsigned getNumElements() const;
630
 
631
  /// Return the size (in bytes) of each element in the array/vector.
632
  /// The size of the elements is known to be a multiple of one byte.
633
  uint64_t getElementByteSize() const;
634
 
635
  /// This method returns true if this is an array of \p CharSize integers.
636
  bool isString(unsigned CharSize = 8) const;
637
 
638
  /// This method returns true if the array "isString", ends with a null byte,
639
  /// and does not contains any other null bytes.
640
  bool isCString() const;
641
 
642
  /// If this array is isString(), then this method returns the array as a
643
  /// StringRef. Otherwise, it asserts out.
644
  StringRef getAsString() const {
645
    assert(isString() && "Not a string");
646
    return getRawDataValues();
647
  }
648
 
649
  /// If this array is isCString(), then this method returns the array (without
650
  /// the trailing null byte) as a StringRef. Otherwise, it asserts out.
651
  StringRef getAsCString() const {
652
    assert(isCString() && "Isn't a C string");
653
    StringRef Str = getAsString();
654
    return Str.substr(0, Str.size() - 1);
655
  }
656
 
657
  /// Return the raw, underlying, bytes of this data. Note that this is an
658
  /// extremely tricky thing to work with, as it exposes the host endianness of
659
  /// the data elements.
660
  StringRef getRawDataValues() const;
661
 
662
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
663
  static bool classof(const Value *V) {
664
    return V->getValueID() == ConstantDataArrayVal ||
665
           V->getValueID() == ConstantDataVectorVal;
666
  }
667
 
668
private:
669
  const char *getElementPointer(unsigned Elt) const;
670
};
671
 
672
//===----------------------------------------------------------------------===//
673
/// An array constant whose element type is a simple 1/2/4/8-byte integer or
674
/// float/double, and whose elements are just simple data values
675
/// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it
676
/// stores all of the elements of the constant as densely packed data, instead
677
/// of as Value*'s.
678
class ConstantDataArray final : public ConstantDataSequential {
679
  friend class ConstantDataSequential;
680
 
681
  explicit ConstantDataArray(Type *ty, const char *Data)
682
      : ConstantDataSequential(ty, ConstantDataArrayVal, Data) {}
683
 
684
public:
685
  ConstantDataArray(const ConstantDataArray &) = delete;
686
 
687
  /// get() constructor - Return a constant with array type with an element
688
  /// count and element type matching the ArrayRef passed in.  Note that this
689
  /// can return a ConstantAggregateZero object.
690
  template <typename ElementTy>
691
  static Constant *get(LLVMContext &Context, ArrayRef<ElementTy> Elts) {
692
    const char *Data = reinterpret_cast<const char *>(Elts.data());
693
    return getRaw(StringRef(Data, Elts.size() * sizeof(ElementTy)), Elts.size(),
694
                  Type::getScalarTy<ElementTy>(Context));
695
  }
696
 
697
  /// get() constructor - ArrayTy needs to be compatible with
698
  /// ArrayRef<ElementTy>. Calls get(LLVMContext, ArrayRef<ElementTy>).
699
  template <typename ArrayTy>
700
  static Constant *get(LLVMContext &Context, ArrayTy &Elts) {
701
    return ConstantDataArray::get(Context, ArrayRef(Elts));
702
  }
703
 
704
  /// getRaw() constructor - Return a constant with array type with an element
705
  /// count and element type matching the NumElements and ElementTy parameters
706
  /// passed in. Note that this can return a ConstantAggregateZero object.
707
  /// ElementTy must be one of i8/i16/i32/i64/half/bfloat/float/double. Data is
708
  /// the buffer containing the elements. Be careful to make sure Data uses the
709
  /// right endianness, the buffer will be used as-is.
710
  static Constant *getRaw(StringRef Data, uint64_t NumElements,
711
                          Type *ElementTy) {
712
    Type *Ty = ArrayType::get(ElementTy, NumElements);
713
    return getImpl(Data, Ty);
714
  }
715
 
716
  /// getFP() constructors - Return a constant of array type with a float
717
  /// element type taken from argument `ElementType', and count taken from
718
  /// argument `Elts'.  The amount of bits of the contained type must match the
719
  /// number of bits of the type contained in the passed in ArrayRef.
720
  /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note
721
  /// that this can return a ConstantAggregateZero object.
722
  static Constant *getFP(Type *ElementType, ArrayRef<uint16_t> Elts);
723
  static Constant *getFP(Type *ElementType, ArrayRef<uint32_t> Elts);
724
  static Constant *getFP(Type *ElementType, ArrayRef<uint64_t> Elts);
725
 
726
  /// This method constructs a CDS and initializes it with a text string.
727
  /// The default behavior (AddNull==true) causes a null terminator to
728
  /// be placed at the end of the array (increasing the length of the string by
729
  /// one more than the StringRef would normally indicate.  Pass AddNull=false
730
  /// to disable this behavior.
731
  static Constant *getString(LLVMContext &Context, StringRef Initializer,
732
                             bool AddNull = true);
733
 
734
  /// Specialize the getType() method to always return an ArrayType,
735
  /// which reduces the amount of casting needed in parts of the compiler.
736
  inline ArrayType *getType() const {
737
    return cast<ArrayType>(Value::getType());
738
  }
739
 
740
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
741
  static bool classof(const Value *V) {
742
    return V->getValueID() == ConstantDataArrayVal;
743
  }
744
};
745
 
746
//===----------------------------------------------------------------------===//
747
/// A vector constant whose element type is a simple 1/2/4/8-byte integer or
748
/// float/double, and whose elements are just simple data values
749
/// (i.e. ConstantInt/ConstantFP). This Constant node has no operands because it
750
/// stores all of the elements of the constant as densely packed data, instead
751
/// of as Value*'s.
752
class ConstantDataVector final : public ConstantDataSequential {
753
  friend class ConstantDataSequential;
754
 
755
  explicit ConstantDataVector(Type *ty, const char *Data)
756
      : ConstantDataSequential(ty, ConstantDataVectorVal, Data),
757
        IsSplatSet(false) {}
758
  // Cache whether or not the constant is a splat.
759
  mutable bool IsSplatSet : 1;
760
  mutable bool IsSplat : 1;
761
  bool isSplatData() const;
762
 
763
public:
764
  ConstantDataVector(const ConstantDataVector &) = delete;
765
 
766
  /// get() constructors - Return a constant with vector type with an element
767
  /// count and element type matching the ArrayRef passed in.  Note that this
768
  /// can return a ConstantAggregateZero object.
769
  static Constant *get(LLVMContext &Context, ArrayRef<uint8_t> Elts);
770
  static Constant *get(LLVMContext &Context, ArrayRef<uint16_t> Elts);
771
  static Constant *get(LLVMContext &Context, ArrayRef<uint32_t> Elts);
772
  static Constant *get(LLVMContext &Context, ArrayRef<uint64_t> Elts);
773
  static Constant *get(LLVMContext &Context, ArrayRef<float> Elts);
774
  static Constant *get(LLVMContext &Context, ArrayRef<double> Elts);
775
 
776
  /// getRaw() constructor - Return a constant with vector type with an element
777
  /// count and element type matching the NumElements and ElementTy parameters
778
  /// passed in. Note that this can return a ConstantAggregateZero object.
779
  /// ElementTy must be one of i8/i16/i32/i64/half/bfloat/float/double. Data is
780
  /// the buffer containing the elements. Be careful to make sure Data uses the
781
  /// right endianness, the buffer will be used as-is.
782
  static Constant *getRaw(StringRef Data, uint64_t NumElements,
783
                          Type *ElementTy) {
784
    Type *Ty = VectorType::get(ElementTy, ElementCount::getFixed(NumElements));
785
    return getImpl(Data, Ty);
786
  }
787
 
788
  /// getFP() constructors - Return a constant of vector type with a float
789
  /// element type taken from argument `ElementType', and count taken from
790
  /// argument `Elts'.  The amount of bits of the contained type must match the
791
  /// number of bits of the type contained in the passed in ArrayRef.
792
  /// (i.e. half or bfloat for 16bits, float for 32bits, double for 64bits) Note
793
  /// that this can return a ConstantAggregateZero object.
794
  static Constant *getFP(Type *ElementType, ArrayRef<uint16_t> Elts);
795
  static Constant *getFP(Type *ElementType, ArrayRef<uint32_t> Elts);
796
  static Constant *getFP(Type *ElementType, ArrayRef<uint64_t> Elts);
797
 
798
  /// Return a ConstantVector with the specified constant in each element.
799
  /// The specified constant has to be a of a compatible type (i8/i16/
800
  /// i32/i64/half/bfloat/float/double) and must be a ConstantFP or ConstantInt.
801
  static Constant *getSplat(unsigned NumElts, Constant *Elt);
802
 
803
  /// Returns true if this is a splat constant, meaning that all elements have
804
  /// the same value.
805
  bool isSplat() const;
806
 
807
  /// If this is a splat constant, meaning that all of the elements have the
808
  /// same value, return that value. Otherwise return NULL.
809
  Constant *getSplatValue() const;
810
 
811
  /// Specialize the getType() method to always return a FixedVectorType,
812
  /// which reduces the amount of casting needed in parts of the compiler.
813
  inline FixedVectorType *getType() const {
814
    return cast<FixedVectorType>(Value::getType());
815
  }
816
 
817
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
818
  static bool classof(const Value *V) {
819
    return V->getValueID() == ConstantDataVectorVal;
820
  }
821
};
822
 
823
//===----------------------------------------------------------------------===//
824
/// A constant token which is empty
825
///
826
class ConstantTokenNone final : public ConstantData {
827
  friend class Constant;
828
 
829
  explicit ConstantTokenNone(LLVMContext &Context)
830
      : ConstantData(Type::getTokenTy(Context), ConstantTokenNoneVal) {}
831
 
832
  void destroyConstantImpl();
833
 
834
public:
835
  ConstantTokenNone(const ConstantTokenNone &) = delete;
836
 
837
  /// Return the ConstantTokenNone.
838
  static ConstantTokenNone *get(LLVMContext &Context);
839
 
840
  /// Methods to support type inquiry through isa, cast, and dyn_cast.
841
  static bool classof(const Value *V) {
842
    return V->getValueID() == ConstantTokenNoneVal;
843
  }
844
};
845
 
846
/// A constant target extension type default initializer
847
class ConstantTargetNone final : public ConstantData {
848
  friend class Constant;
849
 
850
  explicit ConstantTargetNone(TargetExtType *T)
851
      : ConstantData(T, Value::ConstantTargetNoneVal) {}
852
 
853
  void destroyConstantImpl();
854
 
855
public:
856
  ConstantTargetNone(const ConstantTargetNone &) = delete;
857
 
858
  /// Static factory methods - Return objects of the specified value.
859
  static ConstantTargetNone *get(TargetExtType *T);
860
 
861
  /// Specialize the getType() method to always return an TargetExtType,
862
  /// which reduces the amount of casting needed in parts of the compiler.
863
  inline TargetExtType *getType() const {
864
    return cast<TargetExtType>(Value::getType());
865
  }
866
 
867
  /// Methods for support type inquiry through isa, cast, and dyn_cast.
868
  static bool classof(const Value *V) {
869
    return V->getValueID() == ConstantTargetNoneVal;
870
  }
871
};
872
 
873
/// The address of a basic block.
874
///
875
class BlockAddress final : public Constant {
876
  friend class Constant;
877
 
878
  BlockAddress(Function *F, BasicBlock *BB);
879
 
880
  void *operator new(size_t S) { return User::operator new(S, 2); }
881
 
882
  void destroyConstantImpl();
883
  Value *handleOperandChangeImpl(Value *From, Value *To);
884
 
885
public:
886
  void operator delete(void *Ptr) { User::operator delete(Ptr); }
887
 
888
  /// Return a BlockAddress for the specified function and basic block.
889
  static BlockAddress *get(Function *F, BasicBlock *BB);
890
 
891
  /// Return a BlockAddress for the specified basic block.  The basic
892
  /// block must be embedded into a function.
893
  static BlockAddress *get(BasicBlock *BB);
894
 
895
  /// Lookup an existing \c BlockAddress constant for the given BasicBlock.
896
  ///
897
  /// \returns 0 if \c !BB->hasAddressTaken(), otherwise the \c BlockAddress.
898
  static BlockAddress *lookup(const BasicBlock *BB);
899
 
900
  /// Transparently provide more efficient getOperand methods.
901
  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
902
 
903
  Function *getFunction() const { return (Function *)Op<0>().get(); }
904
  BasicBlock *getBasicBlock() const { return (BasicBlock *)Op<1>().get(); }
905
 
906
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
907
  static bool classof(const Value *V) {
908
    return V->getValueID() == BlockAddressVal;
909
  }
910
};
911
 
912
template <>
913
struct OperandTraits<BlockAddress>
914
    : public FixedNumOperandTraits<BlockAddress, 2> {};
915
 
916
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BlockAddress, Value)
917
 
918
/// Wrapper for a function that represents a value that
919
/// functionally represents the original function. This can be a function,
920
/// global alias to a function, or an ifunc.
921
class DSOLocalEquivalent final : public Constant {
922
  friend class Constant;
923
 
924
  DSOLocalEquivalent(GlobalValue *GV);
925
 
926
  void *operator new(size_t S) { return User::operator new(S, 1); }
927
 
928
  void destroyConstantImpl();
929
  Value *handleOperandChangeImpl(Value *From, Value *To);
930
 
931
public:
932
  void operator delete(void *Ptr) { User::operator delete(Ptr); }
933
 
934
  /// Return a DSOLocalEquivalent for the specified global value.
935
  static DSOLocalEquivalent *get(GlobalValue *GV);
936
 
937
  /// Transparently provide more efficient getOperand methods.
938
  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
939
 
940
  GlobalValue *getGlobalValue() const {
941
    return cast<GlobalValue>(Op<0>().get());
942
  }
943
 
944
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
945
  static bool classof(const Value *V) {
946
    return V->getValueID() == DSOLocalEquivalentVal;
947
  }
948
};
949
 
950
template <>
951
struct OperandTraits<DSOLocalEquivalent>
952
    : public FixedNumOperandTraits<DSOLocalEquivalent, 1> {};
953
 
954
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(DSOLocalEquivalent, Value)
955
 
956
/// Wrapper for a value that won't be replaced with a CFI jump table
957
/// pointer in LowerTypeTestsModule.
958
class NoCFIValue final : public Constant {
959
  friend class Constant;
960
 
961
  NoCFIValue(GlobalValue *GV);
962
 
963
  void *operator new(size_t S) { return User::operator new(S, 1); }
964
 
965
  void destroyConstantImpl();
966
  Value *handleOperandChangeImpl(Value *From, Value *To);
967
 
968
public:
969
  /// Return a NoCFIValue for the specified function.
970
  static NoCFIValue *get(GlobalValue *GV);
971
 
972
  /// Transparently provide more efficient getOperand methods.
973
  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
974
 
975
  GlobalValue *getGlobalValue() const {
976
    return cast<GlobalValue>(Op<0>().get());
977
  }
978
 
979
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
980
  static bool classof(const Value *V) {
981
    return V->getValueID() == NoCFIValueVal;
982
  }
983
};
984
 
985
template <>
986
struct OperandTraits<NoCFIValue> : public FixedNumOperandTraits<NoCFIValue, 1> {
987
};
988
 
989
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(NoCFIValue, Value)
990
 
991
//===----------------------------------------------------------------------===//
992
/// A constant value that is initialized with an expression using
993
/// other constant values.
994
///
995
/// This class uses the standard Instruction opcodes to define the various
996
/// constant expressions.  The Opcode field for the ConstantExpr class is
997
/// maintained in the Value::SubclassData field.
998
class ConstantExpr : public Constant {
999
  friend struct ConstantExprKeyType;
1000
  friend class Constant;
1001
 
1002
  void destroyConstantImpl();
1003
  Value *handleOperandChangeImpl(Value *From, Value *To);
1004
 
1005
protected:
1006
  ConstantExpr(Type *ty, unsigned Opcode, Use *Ops, unsigned NumOps)
1007
      : Constant(ty, ConstantExprVal, Ops, NumOps) {
1008
    // Operation type (an Instruction opcode) is stored as the SubclassData.
1009
    setValueSubclassData(Opcode);
1010
  }
1011
 
1012
  ~ConstantExpr() = default;
1013
 
1014
public:
1015
  // Static methods to construct a ConstantExpr of different kinds.  Note that
1016
  // these methods may return a object that is not an instance of the
1017
  // ConstantExpr class, because they will attempt to fold the constant
1018
  // expression into something simpler if possible.
1019
 
1020
  /// getAlignOf constant expr - computes the alignment of a type in a target
1021
  /// independent way (Note: the return type is an i64).
1022
  static Constant *getAlignOf(Type *Ty);
1023
 
1024
  /// getSizeOf constant expr - computes the (alloc) size of a type (in
1025
  /// address-units, not bits) in a target independent way (Note: the return
1026
  /// type is an i64).
1027
  ///
1028
  static Constant *getSizeOf(Type *Ty);
1029
 
1030
  /// getOffsetOf constant expr - computes the offset of a struct field in a
1031
  /// target independent way (Note: the return type is an i64).
1032
  ///
1033
  static Constant *getOffsetOf(StructType *STy, unsigned FieldNo);
1034
 
1035
  /// getOffsetOf constant expr - This is a generalized form of getOffsetOf,
1036
  /// which supports any aggregate type, and any Constant index.
1037
  ///
1038
  static Constant *getOffsetOf(Type *Ty, Constant *FieldNo);
1039
 
1040
  static Constant *getNeg(Constant *C, bool HasNUW = false,
1041
                          bool HasNSW = false);
1042
  static Constant *getNot(Constant *C);
1043
  static Constant *getAdd(Constant *C1, Constant *C2, bool HasNUW = false,
1044
                          bool HasNSW = false);
1045
  static Constant *getSub(Constant *C1, Constant *C2, bool HasNUW = false,
1046
                          bool HasNSW = false);
1047
  static Constant *getMul(Constant *C1, Constant *C2, bool HasNUW = false,
1048
                          bool HasNSW = false);
1049
  static Constant *getAnd(Constant *C1, Constant *C2);
1050
  static Constant *getOr(Constant *C1, Constant *C2);
1051
  static Constant *getXor(Constant *C1, Constant *C2);
1052
  static Constant *getUMin(Constant *C1, Constant *C2);
1053
  static Constant *getShl(Constant *C1, Constant *C2, bool HasNUW = false,
1054
                          bool HasNSW = false);
1055
  static Constant *getLShr(Constant *C1, Constant *C2, bool isExact = false);
1056
  static Constant *getAShr(Constant *C1, Constant *C2, bool isExact = false);
1057
  static Constant *getTrunc(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1058
  static Constant *getSExt(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1059
  static Constant *getZExt(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1060
  static Constant *getFPTrunc(Constant *C, Type *Ty,
1061
                              bool OnlyIfReduced = false);
1062
  static Constant *getFPExtend(Constant *C, Type *Ty,
1063
                               bool OnlyIfReduced = false);
1064
  static Constant *getUIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1065
  static Constant *getSIToFP(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1066
  static Constant *getFPToUI(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1067
  static Constant *getFPToSI(Constant *C, Type *Ty, bool OnlyIfReduced = false);
1068
  static Constant *getPtrToInt(Constant *C, Type *Ty,
1069
                               bool OnlyIfReduced = false);
1070
  static Constant *getIntToPtr(Constant *C, Type *Ty,
1071
                               bool OnlyIfReduced = false);
1072
  static Constant *getBitCast(Constant *C, Type *Ty,
1073
                              bool OnlyIfReduced = false);
1074
  static Constant *getAddrSpaceCast(Constant *C, Type *Ty,
1075
                                    bool OnlyIfReduced = false);
1076
 
1077
  static Constant *getNSWNeg(Constant *C) { return getNeg(C, false, true); }
1078
  static Constant *getNUWNeg(Constant *C) { return getNeg(C, true, false); }
1079
 
1080
  static Constant *getNSWAdd(Constant *C1, Constant *C2) {
1081
    return getAdd(C1, C2, false, true);
1082
  }
1083
 
1084
  static Constant *getNUWAdd(Constant *C1, Constant *C2) {
1085
    return getAdd(C1, C2, true, false);
1086
  }
1087
 
1088
  static Constant *getNSWSub(Constant *C1, Constant *C2) {
1089
    return getSub(C1, C2, false, true);
1090
  }
1091
 
1092
  static Constant *getNUWSub(Constant *C1, Constant *C2) {
1093
    return getSub(C1, C2, true, false);
1094
  }
1095
 
1096
  static Constant *getNSWMul(Constant *C1, Constant *C2) {
1097
    return getMul(C1, C2, false, true);
1098
  }
1099
 
1100
  static Constant *getNUWMul(Constant *C1, Constant *C2) {
1101
    return getMul(C1, C2, true, false);
1102
  }
1103
 
1104
  static Constant *getNSWShl(Constant *C1, Constant *C2) {
1105
    return getShl(C1, C2, false, true);
1106
  }
1107
 
1108
  static Constant *getNUWShl(Constant *C1, Constant *C2) {
1109
    return getShl(C1, C2, true, false);
1110
  }
1111
 
1112
  static Constant *getExactAShr(Constant *C1, Constant *C2) {
1113
    return getAShr(C1, C2, true);
1114
  }
1115
 
1116
  static Constant *getExactLShr(Constant *C1, Constant *C2) {
1117
    return getLShr(C1, C2, true);
1118
  }
1119
 
1120
  /// If C is a scalar/fixed width vector of known powers of 2, then this
1121
  /// function returns a new scalar/fixed width vector obtained from logBase2
1122
  /// of C. Undef vector elements are set to zero.
1123
  /// Return a null pointer otherwise.
1124
  static Constant *getExactLogBase2(Constant *C);
1125
 
1126
  /// Return the identity constant for a binary opcode.
1127
  /// The identity constant C is defined as X op C = X and C op X = X for every
1128
  /// X when the binary operation is commutative. If the binop is not
1129
  /// commutative, callers can acquire the operand 1 identity constant by
1130
  /// setting AllowRHSConstant to true. For example, any shift has a zero
1131
  /// identity constant for operand 1: X shift 0 = X.
1132
  /// If this is a fadd/fsub operation and we don't care about signed zeros,
1133
  /// then setting NSZ to true returns the identity +0.0 instead of -0.0.
1134
  /// Return nullptr if the operator does not have an identity constant.
1135
  static Constant *getBinOpIdentity(unsigned Opcode, Type *Ty,
1136
                                    bool AllowRHSConstant = false,
1137
                                    bool NSZ = false);
1138
 
1139
  /// Return the absorbing element for the given binary
1140
  /// operation, i.e. a constant C such that X op C = C and C op X = C for
1141
  /// every X.  For example, this returns zero for integer multiplication.
1142
  /// It returns null if the operator doesn't have an absorbing element.
1143
  static Constant *getBinOpAbsorber(unsigned Opcode, Type *Ty);
1144
 
1145
  /// Transparently provide more efficient getOperand methods.
1146
  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
1147
 
1148
  /// Convenience function for getting a Cast operation.
1149
  ///
1150
  /// \param ops The opcode for the conversion
1151
  /// \param C  The constant to be converted
1152
  /// \param Ty The type to which the constant is converted
1153
  /// \param OnlyIfReduced see \a getWithOperands() docs.
1154
  static Constant *getCast(unsigned ops, Constant *C, Type *Ty,
1155
                           bool OnlyIfReduced = false);
1156
 
1157
  // Create a ZExt or BitCast cast constant expression
1158
  static Constant *
1159
  getZExtOrBitCast(Constant *C, ///< The constant to zext or bitcast
1160
                   Type *Ty     ///< The type to zext or bitcast C to
1161
  );
1162
 
1163
  // Create a SExt or BitCast cast constant expression
1164
  static Constant *
1165
  getSExtOrBitCast(Constant *C, ///< The constant to sext or bitcast
1166
                   Type *Ty     ///< The type to sext or bitcast C to
1167
  );
1168
 
1169
  // Create a Trunc or BitCast cast constant expression
1170
  static Constant *
1171
  getTruncOrBitCast(Constant *C, ///< The constant to trunc or bitcast
1172
                    Type *Ty     ///< The type to trunc or bitcast C to
1173
  );
1174
 
1175
  /// Create either an sext, trunc or nothing, depending on whether Ty is
1176
  /// wider, narrower or the same as C->getType(). This only works with
1177
  /// integer or vector of integer types.
1178
  static Constant *getSExtOrTrunc(Constant *C, Type *Ty);
1179
 
1180
  /// Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant
1181
  /// expression.
1182
  static Constant *
1183
  getPointerCast(Constant *C, ///< The pointer value to be casted (operand 0)
1184
                 Type *Ty     ///< The type to which cast should be made
1185
  );
1186
 
1187
  /// Create a BitCast or AddrSpaceCast for a pointer type depending on
1188
  /// the address space.
1189
  static Constant *getPointerBitCastOrAddrSpaceCast(
1190
      Constant *C, ///< The constant to addrspacecast or bitcast
1191
      Type *Ty     ///< The type to bitcast or addrspacecast C to
1192
  );
1193
 
1194
  /// Create a ZExt, Bitcast or Trunc for integer -> integer casts
1195
  static Constant *
1196
  getIntegerCast(Constant *C,  ///< The integer constant to be casted
1197
                 Type *Ty,     ///< The integer type to cast to
1198
                 bool IsSigned ///< Whether C should be treated as signed or not
1199
  );
1200
 
1201
  /// Create a FPExt, Bitcast or FPTrunc for fp -> fp casts
1202
  static Constant *getFPCast(Constant *C, ///< The integer constant to be casted
1203
                             Type *Ty     ///< The integer type to cast to
1204
  );
1205
 
1206
  /// Return true if this is a convert constant expression
1207
  bool isCast() const;
1208
 
1209
  /// Return true if this is a compare constant expression
1210
  bool isCompare() const;
1211
 
1212
  /// Select constant expr
1213
  ///
1214
  /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1215
  static Constant *getSelect(Constant *C, Constant *V1, Constant *V2,
1216
                             Type *OnlyIfReducedTy = nullptr);
1217
 
1218
  /// get - Return a binary or shift operator constant expression,
1219
  /// folding if possible.
1220
  ///
1221
  /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1222
  static Constant *get(unsigned Opcode, Constant *C1, Constant *C2,
1223
                       unsigned Flags = 0, Type *OnlyIfReducedTy = nullptr);
1224
 
1225
  /// Return an ICmp or FCmp comparison operator constant expression.
1226
  ///
1227
  /// \param OnlyIfReduced see \a getWithOperands() docs.
1228
  static Constant *getCompare(unsigned short pred, Constant *C1, Constant *C2,
1229
                              bool OnlyIfReduced = false);
1230
 
1231
  /// get* - Return some common constants without having to
1232
  /// specify the full Instruction::OPCODE identifier.
1233
  ///
1234
  static Constant *getICmp(unsigned short pred, Constant *LHS, Constant *RHS,
1235
                           bool OnlyIfReduced = false);
1236
  static Constant *getFCmp(unsigned short pred, Constant *LHS, Constant *RHS,
1237
                           bool OnlyIfReduced = false);
1238
 
1239
  /// Getelementptr form.  Value* is only accepted for convenience;
1240
  /// all elements must be Constants.
1241
  ///
1242
  /// \param InRangeIndex the inrange index if present or std::nullopt.
1243
  /// \param OnlyIfReducedTy see \a getWithOperands() docs.
1244
  static Constant *
1245
  getGetElementPtr(Type *Ty, Constant *C, ArrayRef<Constant *> IdxList,
1246
                   bool InBounds = false,
1247
                   std::optional<unsigned> InRangeIndex = std::nullopt,
1248
                   Type *OnlyIfReducedTy = nullptr) {
1249
    return getGetElementPtr(
1250
        Ty, C, ArrayRef((Value *const *)IdxList.data(), IdxList.size()),
1251
        InBounds, InRangeIndex, OnlyIfReducedTy);
1252
  }
1253
  static Constant *
1254
  getGetElementPtr(Type *Ty, Constant *C, Constant *Idx, bool InBounds = false,
1255
                   std::optional<unsigned> InRangeIndex = std::nullopt,
1256
                   Type *OnlyIfReducedTy = nullptr) {
1257
    // This form of the function only exists to avoid ambiguous overload
1258
    // warnings about whether to convert Idx to ArrayRef<Constant *> or
1259
    // ArrayRef<Value *>.
1260
    return getGetElementPtr(Ty, C, cast<Value>(Idx), InBounds, InRangeIndex,
1261
                            OnlyIfReducedTy);
1262
  }
1263
  static Constant *
1264
  getGetElementPtr(Type *Ty, Constant *C, ArrayRef<Value *> IdxList,
1265
                   bool InBounds = false,
1266
                   std::optional<unsigned> InRangeIndex = std::nullopt,
1267
                   Type *OnlyIfReducedTy = nullptr);
1268
 
1269
  /// Create an "inbounds" getelementptr. See the documentation for the
1270
  /// "inbounds" flag in LangRef.html for details.
1271
  static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1272
                                            ArrayRef<Constant *> IdxList) {
1273
    return getGetElementPtr(Ty, C, IdxList, true);
1274
  }
1275
  static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1276
                                            Constant *Idx) {
1277
    // This form of the function only exists to avoid ambiguous overload
1278
    // warnings about whether to convert Idx to ArrayRef<Constant *> or
1279
    // ArrayRef<Value *>.
1280
    return getGetElementPtr(Ty, C, Idx, true);
1281
  }
1282
  static Constant *getInBoundsGetElementPtr(Type *Ty, Constant *C,
1283
                                            ArrayRef<Value *> IdxList) {
1284
    return getGetElementPtr(Ty, C, IdxList, true);
1285
  }
1286
 
1287
  static Constant *getExtractElement(Constant *Vec, Constant *Idx,
1288
                                     Type *OnlyIfReducedTy = nullptr);
1289
  static Constant *getInsertElement(Constant *Vec, Constant *Elt, Constant *Idx,
1290
                                    Type *OnlyIfReducedTy = nullptr);
1291
  static Constant *getShuffleVector(Constant *V1, Constant *V2,
1292
                                    ArrayRef<int> Mask,
1293
                                    Type *OnlyIfReducedTy = nullptr);
1294
 
1295
  /// Return the opcode at the root of this constant expression
1296
  unsigned getOpcode() const { return getSubclassDataFromValue(); }
1297
 
1298
  /// Return the ICMP or FCMP predicate value. Assert if this is not an ICMP or
1299
  /// FCMP constant expression.
1300
  unsigned getPredicate() const;
1301
 
1302
  /// Assert that this is a shufflevector and return the mask. See class
1303
  /// ShuffleVectorInst for a description of the mask representation.
1304
  ArrayRef<int> getShuffleMask() const;
1305
 
1306
  /// Assert that this is a shufflevector and return the mask.
1307
  ///
1308
  /// TODO: This is a temporary hack until we update the bitcode format for
1309
  /// shufflevector.
1310
  Constant *getShuffleMaskForBitcode() const;
1311
 
1312
  /// Return a string representation for an opcode.
1313
  const char *getOpcodeName() const;
1314
 
1315
  /// This returns the current constant expression with the operands replaced
1316
  /// with the specified values. The specified array must have the same number
1317
  /// of operands as our current one.
1318
  Constant *getWithOperands(ArrayRef<Constant *> Ops) const {
1319
    return getWithOperands(Ops, getType());
1320
  }
1321
 
1322
  /// Get the current expression with the operands replaced.
1323
  ///
1324
  /// Return the current constant expression with the operands replaced with \c
1325
  /// Ops and the type with \c Ty.  The new operands must have the same number
1326
  /// as the current ones.
1327
  ///
1328
  /// If \c OnlyIfReduced is \c true, nullptr will be returned unless something
1329
  /// gets constant-folded, the type changes, or the expression is otherwise
1330
  /// canonicalized.  This parameter should almost always be \c false.
1331
  Constant *getWithOperands(ArrayRef<Constant *> Ops, Type *Ty,
1332
                            bool OnlyIfReduced = false,
1333
                            Type *SrcTy = nullptr) const;
1334
 
1335
  /// Returns an Instruction which implements the same operation as this
1336
  /// ConstantExpr. If \p InsertBefore is not null, the new instruction is
1337
  /// inserted before it, otherwise it is not inserted into any basic block.
1338
  ///
1339
  /// A better approach to this could be to have a constructor for Instruction
1340
  /// which would take a ConstantExpr parameter, but that would have spread
1341
  /// implementation details of ConstantExpr outside of Constants.cpp, which
1342
  /// would make it harder to remove ConstantExprs altogether.
1343
  Instruction *getAsInstruction(Instruction *InsertBefore = nullptr) const;
1344
 
1345
  /// Whether creating a constant expression for this binary operator is
1346
  /// desirable.
1347
  static bool isDesirableBinOp(unsigned Opcode);
1348
 
1349
  /// Whether creating a constant expression for this binary operator is
1350
  /// supported.
1351
  static bool isSupportedBinOp(unsigned Opcode);
1352
 
1353
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
1354
  static bool classof(const Value *V) {
1355
    return V->getValueID() == ConstantExprVal;
1356
  }
1357
 
1358
private:
1359
  // Shadow Value::setValueSubclassData with a private forwarding method so that
1360
  // subclasses cannot accidentally use it.
1361
  void setValueSubclassData(unsigned short D) {
1362
    Value::setValueSubclassData(D);
1363
  }
1364
};
1365
 
1366
template <>
1367
struct OperandTraits<ConstantExpr>
1368
    : public VariadicOperandTraits<ConstantExpr, 1> {};
1369
 
1370
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ConstantExpr, Constant)
1371
 
1372
//===----------------------------------------------------------------------===//
1373
/// 'undef' values are things that do not have specified contents.
1374
/// These are used for a variety of purposes, including global variable
1375
/// initializers and operands to instructions.  'undef' values can occur with
1376
/// any first-class type.
1377
///
1378
/// Undef values aren't exactly constants; if they have multiple uses, they
1379
/// can appear to have different bit patterns at each use. See
1380
/// LangRef.html#undefvalues for details.
1381
///
1382
class UndefValue : public ConstantData {
1383
  friend class Constant;
1384
 
1385
  explicit UndefValue(Type *T) : ConstantData(T, UndefValueVal) {}
1386
 
1387
  void destroyConstantImpl();
1388
 
1389
protected:
1390
  explicit UndefValue(Type *T, ValueTy vty) : ConstantData(T, vty) {}
1391
 
1392
public:
1393
  UndefValue(const UndefValue &) = delete;
1394
 
1395
  /// Static factory methods - Return an 'undef' object of the specified type.
1396
  static UndefValue *get(Type *T);
1397
 
1398
  /// If this Undef has array or vector type, return a undef with the right
1399
  /// element type.
1400
  UndefValue *getSequentialElement() const;
1401
 
1402
  /// If this undef has struct type, return a undef with the right element type
1403
  /// for the specified element.
1404
  UndefValue *getStructElement(unsigned Elt) const;
1405
 
1406
  /// Return an undef of the right value for the specified GEP index if we can,
1407
  /// otherwise return null (e.g. if C is a ConstantExpr).
1408
  UndefValue *getElementValue(Constant *C) const;
1409
 
1410
  /// Return an undef of the right value for the specified GEP index.
1411
  UndefValue *getElementValue(unsigned Idx) const;
1412
 
1413
  /// Return the number of elements in the array, vector, or struct.
1414
  unsigned getNumElements() const;
1415
 
1416
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
1417
  static bool classof(const Value *V) {
1418
    return V->getValueID() == UndefValueVal ||
1419
           V->getValueID() == PoisonValueVal;
1420
  }
1421
};
1422
 
1423
//===----------------------------------------------------------------------===//
1424
/// In order to facilitate speculative execution, many instructions do not
1425
/// invoke immediate undefined behavior when provided with illegal operands,
1426
/// and return a poison value instead.
1427
///
1428
/// see LangRef.html#poisonvalues for details.
1429
///
1430
class PoisonValue final : public UndefValue {
1431
  friend class Constant;
1432
 
1433
  explicit PoisonValue(Type *T) : UndefValue(T, PoisonValueVal) {}
1434
 
1435
  void destroyConstantImpl();
1436
 
1437
public:
1438
  PoisonValue(const PoisonValue &) = delete;
1439
 
1440
  /// Static factory methods - Return an 'poison' object of the specified type.
1441
  static PoisonValue *get(Type *T);
1442
 
1443
  /// If this poison has array or vector type, return a poison with the right
1444
  /// element type.
1445
  PoisonValue *getSequentialElement() const;
1446
 
1447
  /// If this poison has struct type, return a poison with the right element
1448
  /// type for the specified element.
1449
  PoisonValue *getStructElement(unsigned Elt) const;
1450
 
1451
  /// Return an poison of the right value for the specified GEP index if we can,
1452
  /// otherwise return null (e.g. if C is a ConstantExpr).
1453
  PoisonValue *getElementValue(Constant *C) const;
1454
 
1455
  /// Return an poison of the right value for the specified GEP index.
1456
  PoisonValue *getElementValue(unsigned Idx) const;
1457
 
1458
  /// Methods for support type inquiry through isa, cast, and dyn_cast:
1459
  static bool classof(const Value *V) {
1460
    return V->getValueID() == PoisonValueVal;
1461
  }
1462
};
1463
 
1464
} // end namespace llvm
1465
 
1466
#endif // LLVM_IR_CONSTANTS_H