1//===-- ConstantsContext.h - Constants-related Context Interals -----------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines various helper methods and classes used by
11// LLVMContextImpl for creating and managing constants.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_LIB_IR_CONSTANTSCONTEXT_H
16#define LLVM_LIB_IR_CONSTANTSCONTEXT_H
17
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/Hashing.h"
20#include "llvm/IR/InlineAsm.h"
21#include "llvm/IR/Instructions.h"
22#include "llvm/IR/Operator.h"
23#include "llvm/Support/Debug.h"
24#include "llvm/Support/ErrorHandling.h"
25#include "llvm/Support/raw_ostream.h"
26#include <map>
27#include <tuple>
28
29#define DEBUG_TYPE "ir"
30
31namespace llvm {
32
33/// UnaryConstantExpr - This class is private to Constants.cpp, and is used
34/// behind the scenes to implement unary constant exprs.
35class UnaryConstantExpr : public ConstantExpr {
36  void anchor() override;
37  void *operator new(size_t, unsigned) = delete;
38public:
39  // allocate space for exactly one operand
40  void *operator new(size_t s) {
41    return User::operator new(s, 1);
42  }
43  UnaryConstantExpr(unsigned Opcode, Constant *C, Type *Ty)
44    : ConstantExpr(Ty, Opcode, &Op<0>(), 1) {
45    Op<0>() = C;
46  }
47  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
48};
49
50/// BinaryConstantExpr - This class is private to Constants.cpp, and is used
51/// behind the scenes to implement binary constant exprs.
52class BinaryConstantExpr : public ConstantExpr {
53  void anchor() override;
54  void *operator new(size_t, unsigned) = delete;
55public:
56  // allocate space for exactly two operands
57  void *operator new(size_t s) {
58    return User::operator new(s, 2);
59  }
60  BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2,
61                     unsigned Flags)
62    : ConstantExpr(C1->getType(), Opcode, &Op<0>(), 2) {
63    Op<0>() = C1;
64    Op<1>() = C2;
65    SubclassOptionalData = Flags;
66  }
67  /// Transparently provide more efficient getOperand methods.
68  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
69};
70
71/// SelectConstantExpr - This class is private to Constants.cpp, and is used
72/// behind the scenes to implement select constant exprs.
73class SelectConstantExpr : public ConstantExpr {
74  void anchor() override;
75  void *operator new(size_t, unsigned) = delete;
76public:
77  // allocate space for exactly three operands
78  void *operator new(size_t s) {
79    return User::operator new(s, 3);
80  }
81  SelectConstantExpr(Constant *C1, Constant *C2, Constant *C3)
82    : ConstantExpr(C2->getType(), Instruction::Select, &Op<0>(), 3) {
83    Op<0>() = C1;
84    Op<1>() = C2;
85    Op<2>() = C3;
86  }
87  /// Transparently provide more efficient getOperand methods.
88  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
89};
90
91/// ExtractElementConstantExpr - This class is private to
92/// Constants.cpp, and is used behind the scenes to implement
93/// extractelement constant exprs.
94class ExtractElementConstantExpr : public ConstantExpr {
95  void anchor() override;
96  void *operator new(size_t, unsigned) = delete;
97public:
98  // allocate space for exactly two operands
99  void *operator new(size_t s) {
100    return User::operator new(s, 2);
101  }
102  ExtractElementConstantExpr(Constant *C1, Constant *C2)
103    : ConstantExpr(cast<VectorType>(C1->getType())->getElementType(),
104                   Instruction::ExtractElement, &Op<0>(), 2) {
105    Op<0>() = C1;
106    Op<1>() = C2;
107  }
108  /// Transparently provide more efficient getOperand methods.
109  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
110};
111
112/// InsertElementConstantExpr - This class is private to
113/// Constants.cpp, and is used behind the scenes to implement
114/// insertelement constant exprs.
115class InsertElementConstantExpr : public ConstantExpr {
116  void anchor() override;
117  void *operator new(size_t, unsigned) = delete;
118public:
119  // allocate space for exactly three operands
120  void *operator new(size_t s) {
121    return User::operator new(s, 3);
122  }
123  InsertElementConstantExpr(Constant *C1, Constant *C2, Constant *C3)
124    : ConstantExpr(C1->getType(), Instruction::InsertElement,
125                   &Op<0>(), 3) {
126    Op<0>() = C1;
127    Op<1>() = C2;
128    Op<2>() = C3;
129  }
130  /// Transparently provide more efficient getOperand methods.
131  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
132};
133
134/// ShuffleVectorConstantExpr - This class is private to
135/// Constants.cpp, and is used behind the scenes to implement
136/// shufflevector constant exprs.
137class ShuffleVectorConstantExpr : public ConstantExpr {
138  void anchor() override;
139  void *operator new(size_t, unsigned) = delete;
140public:
141  // allocate space for exactly three operands
142  void *operator new(size_t s) {
143    return User::operator new(s, 3);
144  }
145  ShuffleVectorConstantExpr(Constant *C1, Constant *C2, Constant *C3)
146  : ConstantExpr(VectorType::get(
147                   cast<VectorType>(C1->getType())->getElementType(),
148                   cast<VectorType>(C3->getType())->getNumElements()),
149                 Instruction::ShuffleVector,
150                 &Op<0>(), 3) {
151    Op<0>() = C1;
152    Op<1>() = C2;
153    Op<2>() = C3;
154  }
155  /// Transparently provide more efficient getOperand methods.
156  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
157};
158
159/// ExtractValueConstantExpr - This class is private to
160/// Constants.cpp, and is used behind the scenes to implement
161/// extractvalue constant exprs.
162class ExtractValueConstantExpr : public ConstantExpr {
163  void anchor() override;
164  void *operator new(size_t, unsigned) = delete;
165public:
166  // allocate space for exactly one operand
167  void *operator new(size_t s) {
168    return User::operator new(s, 1);
169  }
170  ExtractValueConstantExpr(Constant *Agg, ArrayRef<unsigned> IdxList,
171                           Type *DestTy)
172      : ConstantExpr(DestTy, Instruction::ExtractValue, &Op<0>(), 1),
173        Indices(IdxList.begin(), IdxList.end()) {
174    Op<0>() = Agg;
175  }
176
177  /// Indices - These identify which value to extract.
178  const SmallVector<unsigned, 4> Indices;
179
180  /// Transparently provide more efficient getOperand methods.
181  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
182
183  static bool classof(const ConstantExpr *CE) {
184    return CE->getOpcode() == Instruction::ExtractValue;
185  }
186  static bool classof(const Value *V) {
187    return isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V));
188  }
189};
190
191/// InsertValueConstantExpr - This class is private to
192/// Constants.cpp, and is used behind the scenes to implement
193/// insertvalue constant exprs.
194class InsertValueConstantExpr : public ConstantExpr {
195  void anchor() override;
196  void *operator new(size_t, unsigned) = delete;
197public:
198  // allocate space for exactly one operand
199  void *operator new(size_t s) {
200    return User::operator new(s, 2);
201  }
202  InsertValueConstantExpr(Constant *Agg, Constant *Val,
203                          ArrayRef<unsigned> IdxList, Type *DestTy)
204      : ConstantExpr(DestTy, Instruction::InsertValue, &Op<0>(), 2),
205        Indices(IdxList.begin(), IdxList.end()) {
206    Op<0>() = Agg;
207    Op<1>() = Val;
208  }
209
210  /// Indices - These identify the position for the insertion.
211  const SmallVector<unsigned, 4> Indices;
212
213  /// Transparently provide more efficient getOperand methods.
214  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
215
216  static bool classof(const ConstantExpr *CE) {
217    return CE->getOpcode() == Instruction::InsertValue;
218  }
219  static bool classof(const Value *V) {
220    return isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V));
221  }
222};
223
224/// GetElementPtrConstantExpr - This class is private to Constants.cpp, and is
225/// used behind the scenes to implement getelementpr constant exprs.
226class GetElementPtrConstantExpr : public ConstantExpr {
227  Type *SrcElementTy;
228  void anchor() override;
229  GetElementPtrConstantExpr(Type *SrcElementTy, Constant *C,
230                            ArrayRef<Constant *> IdxList, Type *DestTy);
231
232public:
233  static GetElementPtrConstantExpr *Create(Constant *C,
234                                           ArrayRef<Constant*> IdxList,
235                                           Type *DestTy,
236                                           unsigned Flags) {
237    return Create(
238        cast<PointerType>(C->getType()->getScalarType())->getElementType(), C,
239        IdxList, DestTy, Flags);
240  }
241  static GetElementPtrConstantExpr *Create(Type *SrcElementTy, Constant *C,
242                                           ArrayRef<Constant *> IdxList,
243                                           Type *DestTy, unsigned Flags) {
244    GetElementPtrConstantExpr *Result = new (IdxList.size() + 1)
245        GetElementPtrConstantExpr(SrcElementTy, C, IdxList, DestTy);
246    Result->SubclassOptionalData = Flags;
247    return Result;
248  }
249  Type *getSourceElementType() const;
250  /// Transparently provide more efficient getOperand methods.
251  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
252
253  static bool classof(const ConstantExpr *CE) {
254    return CE->getOpcode() == Instruction::GetElementPtr;
255  }
256  static bool classof(const Value *V) {
257    return isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V));
258  }
259};
260
261// CompareConstantExpr - This class is private to Constants.cpp, and is used
262// behind the scenes to implement ICmp and FCmp constant expressions. This is
263// needed in order to store the predicate value for these instructions.
264class CompareConstantExpr : public ConstantExpr {
265  void anchor() override;
266  void *operator new(size_t, unsigned) = delete;
267public:
268  // allocate space for exactly two operands
269  void *operator new(size_t s) {
270    return User::operator new(s, 2);
271  }
272  unsigned short predicate;
273  CompareConstantExpr(Type *ty, Instruction::OtherOps opc,
274                      unsigned short pred,  Constant* LHS, Constant* RHS)
275    : ConstantExpr(ty, opc, &Op<0>(), 2), predicate(pred) {
276    Op<0>() = LHS;
277    Op<1>() = RHS;
278  }
279  /// Transparently provide more efficient getOperand methods.
280  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
281
282  static bool classof(const ConstantExpr *CE) {
283    return CE->getOpcode() == Instruction::ICmp ||
284           CE->getOpcode() == Instruction::FCmp;
285  }
286  static bool classof(const Value *V) {
287    return isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V));
288  }
289};
290
291template <>
292struct OperandTraits<UnaryConstantExpr>
293    : public FixedNumOperandTraits<UnaryConstantExpr, 1> {};
294DEFINE_TRANSPARENT_OPERAND_ACCESSORS(UnaryConstantExpr, Value)
295
296template <>
297struct OperandTraits<BinaryConstantExpr>
298    : public FixedNumOperandTraits<BinaryConstantExpr, 2> {};
299DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BinaryConstantExpr, Value)
300
301template <>
302struct OperandTraits<SelectConstantExpr>
303    : public FixedNumOperandTraits<SelectConstantExpr, 3> {};
304DEFINE_TRANSPARENT_OPERAND_ACCESSORS(SelectConstantExpr, Value)
305
306template <>
307struct OperandTraits<ExtractElementConstantExpr>
308    : public FixedNumOperandTraits<ExtractElementConstantExpr, 2> {};
309DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractElementConstantExpr, Value)
310
311template <>
312struct OperandTraits<InsertElementConstantExpr>
313    : public FixedNumOperandTraits<InsertElementConstantExpr, 3> {};
314DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertElementConstantExpr, Value)
315
316template <>
317struct OperandTraits<ShuffleVectorConstantExpr>
318    : public FixedNumOperandTraits<ShuffleVectorConstantExpr, 3> {};
319DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ShuffleVectorConstantExpr, Value)
320
321template <>
322struct OperandTraits<ExtractValueConstantExpr>
323    : public FixedNumOperandTraits<ExtractValueConstantExpr, 1> {};
324DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractValueConstantExpr, Value)
325
326template <>
327struct OperandTraits<InsertValueConstantExpr>
328    : public FixedNumOperandTraits<InsertValueConstantExpr, 2> {};
329DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertValueConstantExpr, Value)
330
331template <>
332struct OperandTraits<GetElementPtrConstantExpr>
333    : public VariadicOperandTraits<GetElementPtrConstantExpr, 1> {};
334
335DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrConstantExpr, Value)
336
337template <>
338struct OperandTraits<CompareConstantExpr>
339    : public FixedNumOperandTraits<CompareConstantExpr, 2> {};
340DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CompareConstantExpr, Value)
341
342template <class ConstantClass> struct ConstantAggrKeyType;
343struct InlineAsmKeyType;
344struct ConstantExprKeyType;
345
346template <class ConstantClass> struct ConstantInfo;
347template <> struct ConstantInfo<ConstantExpr> {
348  typedef ConstantExprKeyType ValType;
349  typedef Type TypeClass;
350};
351template <> struct ConstantInfo<InlineAsm> {
352  typedef InlineAsmKeyType ValType;
353  typedef PointerType TypeClass;
354};
355template <> struct ConstantInfo<ConstantArray> {
356  typedef ConstantAggrKeyType<ConstantArray> ValType;
357  typedef ArrayType TypeClass;
358};
359template <> struct ConstantInfo<ConstantStruct> {
360  typedef ConstantAggrKeyType<ConstantStruct> ValType;
361  typedef StructType TypeClass;
362};
363template <> struct ConstantInfo<ConstantVector> {
364  typedef ConstantAggrKeyType<ConstantVector> ValType;
365  typedef VectorType TypeClass;
366};
367
368template <class ConstantClass> struct ConstantAggrKeyType {
369  ArrayRef<Constant *> Operands;
370  ConstantAggrKeyType(ArrayRef<Constant *> Operands) : Operands(Operands) {}
371  ConstantAggrKeyType(ArrayRef<Constant *> Operands, const ConstantClass *)
372      : Operands(Operands) {}
373  ConstantAggrKeyType(const ConstantClass *C,
374                      SmallVectorImpl<Constant *> &Storage) {
375    assert(Storage.empty() && "Expected empty storage");
376    for (unsigned I = 0, E = C->getNumOperands(); I != E; ++I)
377      Storage.push_back(C->getOperand(I));
378    Operands = Storage;
379  }
380
381  bool operator==(const ConstantAggrKeyType &X) const {
382    return Operands == X.Operands;
383  }
384  bool operator==(const ConstantClass *C) const {
385    if (Operands.size() != C->getNumOperands())
386      return false;
387    for (unsigned I = 0, E = Operands.size(); I != E; ++I)
388      if (Operands[I] != C->getOperand(I))
389        return false;
390    return true;
391  }
392  unsigned getHash() const {
393    return hash_combine_range(Operands.begin(), Operands.end());
394  }
395
396  typedef typename ConstantInfo<ConstantClass>::TypeClass TypeClass;
397  ConstantClass *create(TypeClass *Ty) const {
398    return new (Operands.size()) ConstantClass(Ty, Operands);
399  }
400};
401
402struct InlineAsmKeyType {
403  StringRef AsmString;
404  StringRef Constraints;
405  FunctionType *FTy;
406  bool HasSideEffects;
407  bool IsAlignStack;
408  InlineAsm::AsmDialect AsmDialect;
409
410  InlineAsmKeyType(StringRef AsmString, StringRef Constraints,
411                   FunctionType *FTy, bool HasSideEffects, bool IsAlignStack,
412                   InlineAsm::AsmDialect AsmDialect)
413      : AsmString(AsmString), Constraints(Constraints), FTy(FTy),
414        HasSideEffects(HasSideEffects), IsAlignStack(IsAlignStack),
415        AsmDialect(AsmDialect) {}
416  InlineAsmKeyType(const InlineAsm *Asm, SmallVectorImpl<Constant *> &)
417      : AsmString(Asm->getAsmString()), Constraints(Asm->getConstraintString()),
418        FTy(Asm->getFunctionType()), HasSideEffects(Asm->hasSideEffects()),
419        IsAlignStack(Asm->isAlignStack()), AsmDialect(Asm->getDialect()) {}
420
421  bool operator==(const InlineAsmKeyType &X) const {
422    return HasSideEffects == X.HasSideEffects &&
423           IsAlignStack == X.IsAlignStack && AsmDialect == X.AsmDialect &&
424           AsmString == X.AsmString && Constraints == X.Constraints &&
425           FTy == X.FTy;
426  }
427  bool operator==(const InlineAsm *Asm) const {
428    return HasSideEffects == Asm->hasSideEffects() &&
429           IsAlignStack == Asm->isAlignStack() &&
430           AsmDialect == Asm->getDialect() &&
431           AsmString == Asm->getAsmString() &&
432           Constraints == Asm->getConstraintString() &&
433           FTy == Asm->getFunctionType();
434  }
435  unsigned getHash() const {
436    return hash_combine(AsmString, Constraints, HasSideEffects, IsAlignStack,
437                        AsmDialect, FTy);
438  }
439
440  typedef ConstantInfo<InlineAsm>::TypeClass TypeClass;
441  InlineAsm *create(TypeClass *Ty) const {
442    assert(PointerType::getUnqual(FTy) == Ty);
443    return new InlineAsm(FTy, AsmString, Constraints, HasSideEffects,
444                         IsAlignStack, AsmDialect);
445  }
446};
447
448struct ConstantExprKeyType {
449  uint8_t Opcode;
450  uint8_t SubclassOptionalData;
451  uint16_t SubclassData;
452  ArrayRef<Constant *> Ops;
453  ArrayRef<unsigned> Indexes;
454  Type *ExplicitTy;
455
456  ConstantExprKeyType(unsigned Opcode, ArrayRef<Constant *> Ops,
457                      unsigned short SubclassData = 0,
458                      unsigned short SubclassOptionalData = 0,
459                      ArrayRef<unsigned> Indexes = None,
460                      Type *ExplicitTy = nullptr)
461      : Opcode(Opcode), SubclassOptionalData(SubclassOptionalData),
462        SubclassData(SubclassData), Ops(Ops), Indexes(Indexes),
463        ExplicitTy(ExplicitTy) {}
464  ConstantExprKeyType(ArrayRef<Constant *> Operands, const ConstantExpr *CE)
465      : Opcode(CE->getOpcode()),
466        SubclassOptionalData(CE->getRawSubclassOptionalData()),
467        SubclassData(CE->isCompare() ? CE->getPredicate() : 0), Ops(Operands),
468        Indexes(CE->hasIndices() ? CE->getIndices() : ArrayRef<unsigned>()) {}
469  ConstantExprKeyType(const ConstantExpr *CE,
470                      SmallVectorImpl<Constant *> &Storage)
471      : Opcode(CE->getOpcode()),
472        SubclassOptionalData(CE->getRawSubclassOptionalData()),
473        SubclassData(CE->isCompare() ? CE->getPredicate() : 0),
474        Indexes(CE->hasIndices() ? CE->getIndices() : ArrayRef<unsigned>()) {
475    assert(Storage.empty() && "Expected empty storage");
476    for (unsigned I = 0, E = CE->getNumOperands(); I != E; ++I)
477      Storage.push_back(CE->getOperand(I));
478    Ops = Storage;
479  }
480
481  bool operator==(const ConstantExprKeyType &X) const {
482    return Opcode == X.Opcode && SubclassData == X.SubclassData &&
483           SubclassOptionalData == X.SubclassOptionalData && Ops == X.Ops &&
484           Indexes == X.Indexes;
485  }
486
487  bool operator==(const ConstantExpr *CE) const {
488    if (Opcode != CE->getOpcode())
489      return false;
490    if (SubclassOptionalData != CE->getRawSubclassOptionalData())
491      return false;
492    if (Ops.size() != CE->getNumOperands())
493      return false;
494    if (SubclassData != (CE->isCompare() ? CE->getPredicate() : 0))
495      return false;
496    for (unsigned I = 0, E = Ops.size(); I != E; ++I)
497      if (Ops[I] != CE->getOperand(I))
498        return false;
499    if (Indexes != (CE->hasIndices() ? CE->getIndices() : ArrayRef<unsigned>()))
500      return false;
501    return true;
502  }
503
504  unsigned getHash() const {
505    return hash_combine(Opcode, SubclassOptionalData, SubclassData,
506                        hash_combine_range(Ops.begin(), Ops.end()),
507                        hash_combine_range(Indexes.begin(), Indexes.end()));
508  }
509
510  typedef ConstantInfo<ConstantExpr>::TypeClass TypeClass;
511  ConstantExpr *create(TypeClass *Ty) const {
512    switch (Opcode) {
513    default:
514      if (Instruction::isCast(Opcode))
515        return new UnaryConstantExpr(Opcode, Ops[0], Ty);
516      if ((Opcode >= Instruction::BinaryOpsBegin &&
517           Opcode < Instruction::BinaryOpsEnd))
518        return new BinaryConstantExpr(Opcode, Ops[0], Ops[1],
519                                      SubclassOptionalData);
520      llvm_unreachable("Invalid ConstantExpr!");
521    case Instruction::Select:
522      return new SelectConstantExpr(Ops[0], Ops[1], Ops[2]);
523    case Instruction::ExtractElement:
524      return new ExtractElementConstantExpr(Ops[0], Ops[1]);
525    case Instruction::InsertElement:
526      return new InsertElementConstantExpr(Ops[0], Ops[1], Ops[2]);
527    case Instruction::ShuffleVector:
528      return new ShuffleVectorConstantExpr(Ops[0], Ops[1], Ops[2]);
529    case Instruction::InsertValue:
530      return new InsertValueConstantExpr(Ops[0], Ops[1], Indexes, Ty);
531    case Instruction::ExtractValue:
532      return new ExtractValueConstantExpr(Ops[0], Indexes, Ty);
533    case Instruction::GetElementPtr:
534      return GetElementPtrConstantExpr::Create(
535          ExplicitTy ? ExplicitTy
536                     : cast<PointerType>(Ops[0]->getType()->getScalarType())
537                           ->getElementType(),
538          Ops[0], Ops.slice(1), Ty, SubclassOptionalData);
539    case Instruction::ICmp:
540      return new CompareConstantExpr(Ty, Instruction::ICmp, SubclassData,
541                                     Ops[0], Ops[1]);
542    case Instruction::FCmp:
543      return new CompareConstantExpr(Ty, Instruction::FCmp, SubclassData,
544                                     Ops[0], Ops[1]);
545    }
546  }
547};
548
549template <class ConstantClass> class ConstantUniqueMap {
550public:
551  typedef typename ConstantInfo<ConstantClass>::ValType ValType;
552  typedef typename ConstantInfo<ConstantClass>::TypeClass TypeClass;
553  typedef std::pair<TypeClass *, ValType> LookupKey;
554
555private:
556  struct MapInfo {
557    typedef DenseMapInfo<ConstantClass *> ConstantClassInfo;
558    static inline ConstantClass *getEmptyKey() {
559      return ConstantClassInfo::getEmptyKey();
560    }
561    static inline ConstantClass *getTombstoneKey() {
562      return ConstantClassInfo::getTombstoneKey();
563    }
564    static unsigned getHashValue(const ConstantClass *CP) {
565      SmallVector<Constant *, 8> Storage;
566      return getHashValue(LookupKey(CP->getType(), ValType(CP, Storage)));
567    }
568    static bool isEqual(const ConstantClass *LHS, const ConstantClass *RHS) {
569      return LHS == RHS;
570    }
571    static unsigned getHashValue(const LookupKey &Val) {
572      return hash_combine(Val.first, Val.second.getHash());
573    }
574    static bool isEqual(const LookupKey &LHS, const ConstantClass *RHS) {
575      if (RHS == getEmptyKey() || RHS == getTombstoneKey())
576        return false;
577      if (LHS.first != RHS->getType())
578        return false;
579      return LHS.second == RHS;
580    }
581  };
582
583public:
584  typedef DenseMap<ConstantClass *, char, MapInfo> MapTy;
585
586private:
587  MapTy Map;
588
589public:
590  typename MapTy::iterator map_begin() { return Map.begin(); }
591  typename MapTy::iterator map_end() { return Map.end(); }
592
593  void freeConstants() {
594    for (auto &I : Map)
595      // Asserts that use_empty().
596      delete I.first;
597  }
598
599private:
600  ConstantClass *create(TypeClass *Ty, ValType V) {
601    ConstantClass *Result = V.create(Ty);
602
603    assert(Result->getType() == Ty && "Type specified is not correct!");
604    insert(Result);
605
606    return Result;
607  }
608
609public:
610  /// Return the specified constant from the map, creating it if necessary.
611  ConstantClass *getOrCreate(TypeClass *Ty, ValType V) {
612    LookupKey Lookup(Ty, V);
613    ConstantClass *Result = nullptr;
614
615    auto I = find(Lookup);
616    if (I == Map.end())
617      Result = create(Ty, V);
618    else
619      Result = I->first;
620    assert(Result && "Unexpected nullptr");
621
622    return Result;
623  }
624
625  /// Find the constant by lookup key.
626  typename MapTy::iterator find(LookupKey Lookup) {
627    return Map.find_as(Lookup);
628  }
629
630  /// Insert the constant into its proper slot.
631  void insert(ConstantClass *CP) { Map[CP] = '\0'; }
632
633  /// Remove this constant from the map
634  void remove(ConstantClass *CP) {
635    typename MapTy::iterator I = Map.find(CP);
636    assert(I != Map.end() && "Constant not found in constant table!");
637    assert(I->first == CP && "Didn't find correct element?");
638    Map.erase(I);
639  }
640
641  ConstantClass *replaceOperandsInPlace(ArrayRef<Constant *> Operands,
642                                        ConstantClass *CP, Value *From,
643                                        Constant *To, unsigned NumUpdated = 0,
644                                        unsigned OperandNo = ~0u) {
645    LookupKey Lookup(CP->getType(), ValType(Operands, CP));
646    auto I = find(Lookup);
647    if (I != Map.end())
648      return I->first;
649
650    // Update to the new value.  Optimize for the case when we have a single
651    // operand that we're changing, but handle bulk updates efficiently.
652    remove(CP);
653    if (NumUpdated == 1) {
654      assert(OperandNo < CP->getNumOperands() && "Invalid index");
655      assert(CP->getOperand(OperandNo) != To && "I didn't contain From!");
656      CP->setOperand(OperandNo, To);
657    } else {
658      for (unsigned I = 0, E = CP->getNumOperands(); I != E; ++I)
659        if (CP->getOperand(I) == From)
660          CP->setOperand(I, To);
661    }
662    insert(CP);
663    return nullptr;
664  }
665
666  void dump() const { DEBUG(dbgs() << "Constant.cpp: ConstantUniqueMap\n"); }
667};
668
669} // end namespace llvm
670
671#endif
672