lib/VMCore/ConstantsContext.h

   1 //===---------------- ConstantsContext.h - Implementation ------*- C++ -*--===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 //  This file defines various helper methods and classes used by
  11 // LLVMContextImpl for creating and managing constants.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_CONSTANTSCONTEXT_H
  16 #define LLVM_CONSTANTSCONTEXT_H
  17
  18 #include "llvm/Instructions.h"
  19 #include "llvm/Metadata.h"
  20 #include "llvm/Operator.h"
  21 #include "llvm/Support/Debug.h"
  22 #include "llvm/Support/ErrorHandling.h"
  23 #include "llvm/System/Mutex.h"
  24 #include "llvm/System/RWMutex.h"
  25 #include <map>
  26
  27 namespace llvm {
  28 template<class ValType>
  29 struct ConstantTraits;
  30
  31 /// UnaryConstantExpr - This class is private to Constants.cpp, and is used
  32 /// behind the scenes to implement unary constant exprs.
  33 class UnaryConstantExpr : public ConstantExpr {
  34   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  35 public:
  36   // allocate space for exactly one operand
  37   void *operator new(size_t s) {
  38     return User::operator new(s, 1);
  39   }
  40   UnaryConstantExpr(unsigned Opcode, Constant *C, const Type *Ty)
  41     : ConstantExpr(Ty, Opcode, &Op<0>(), 1) {
  42     Op<0>() = C;
  43   }
  44   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
  45 };
  46
  47 /// BinaryConstantExpr - This class is private to Constants.cpp, and is used
  48 /// behind the scenes to implement binary constant exprs.
  49 class BinaryConstantExpr : public ConstantExpr {
  50   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  51 public:
  52   // allocate space for exactly two operands
  53   void *operator new(size_t s) {
  54     return User::operator new(s, 2);
  55   }
  56   BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2)
  57     : ConstantExpr(C1->getType(), Opcode, &Op<0>(), 2) {
  58     Op<0>() = C1;
  59     Op<1>() = C2;
  60   }
  61   /// Transparently provide more efficient getOperand methods.
  62   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
  63 };
  64
  65 /// SelectConstantExpr - This class is private to Constants.cpp, and is used
  66 /// behind the scenes to implement select constant exprs.
  67 class SelectConstantExpr : public ConstantExpr {
  68   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  69 public:
  70   // allocate space for exactly three operands
  71   void *operator new(size_t s) {
  72     return User::operator new(s, 3);
  73   }
  74   SelectConstantExpr(Constant *C1, Constant *C2, Constant *C3)
  75     : ConstantExpr(C2->getType(), Instruction::Select, &Op<0>(), 3) {
  76     Op<0>() = C1;
  77     Op<1>() = C2;
  78     Op<2>() = C3;
  79   }
  80   /// Transparently provide more efficient getOperand methods.
  81   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
  82 };
  83
  84 /// ExtractElementConstantExpr - This class is private to
  85 /// Constants.cpp, and is used behind the scenes to implement
  86 /// extractelement constant exprs.
  87 class ExtractElementConstantExpr : public ConstantExpr {
  88   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  89 public:
  90   // allocate space for exactly two operands
  91   void *operator new(size_t s) {
  92     return User::operator new(s, 2);
  93   }
  94   ExtractElementConstantExpr(Constant *C1, Constant *C2)
  95     : ConstantExpr(cast<VectorType>(C1->getType())->getElementType(),
  96                    Instruction::ExtractElement, &Op<0>(), 2) {
  97     Op<0>() = C1;
  98     Op<1>() = C2;
  99   }
 100   /// Transparently provide more efficient getOperand methods.
 101   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 102 };
 103
 104 /// InsertElementConstantExpr - This class is private to
 105 /// Constants.cpp, and is used behind the scenes to implement
 106 /// insertelement constant exprs.
 107 class InsertElementConstantExpr : public ConstantExpr {
 108   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 109 public:
 110   // allocate space for exactly three operands
 111   void *operator new(size_t s) {
 112     return User::operator new(s, 3);
 113   }
 114   InsertElementConstantExpr(Constant *C1, Constant *C2, Constant *C3)
 115     : ConstantExpr(C1->getType(), Instruction::InsertElement,
 116                    &Op<0>(), 3) {
 117     Op<0>() = C1;
 118     Op<1>() = C2;
 119     Op<2>() = C3;
 120   }
 121   /// Transparently provide more efficient getOperand methods.
 122   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 123 };
 124
 125 /// ShuffleVectorConstantExpr - This class is private to
 126 /// Constants.cpp, and is used behind the scenes to implement
 127 /// shufflevector constant exprs.
 128 class ShuffleVectorConstantExpr : public ConstantExpr {
 129   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 130 public:
 131   // allocate space for exactly three operands
 132   void *operator new(size_t s) {
 133     return User::operator new(s, 3);
 134   }
 135   ShuffleVectorConstantExpr(Constant *C1, Constant *C2, Constant *C3)
 136   : ConstantExpr(VectorType::get(
 137                    cast<VectorType>(C1->getType())->getElementType(),
 138                    cast<VectorType>(C3->getType())->getNumElements()),
 139                  Instruction::ShuffleVector,
 140                  &Op<0>(), 3) {
 141     Op<0>() = C1;
 142     Op<1>() = C2;
 143     Op<2>() = C3;
 144   }
 145   /// Transparently provide more efficient getOperand methods.
 146   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 147 };
 148
 149 /// ExtractValueConstantExpr - This class is private to
 150 /// Constants.cpp, and is used behind the scenes to implement
 151 /// extractvalue constant exprs.
 152 class ExtractValueConstantExpr : public ConstantExpr {
 153   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 154 public:
 155   // allocate space for exactly one operand
 156   void *operator new(size_t s) {
 157     return User::operator new(s, 1);
 158   }
 159   ExtractValueConstantExpr(Constant *Agg,
 160                            const SmallVector<unsigned, 4> &IdxList,
 161                            const Type *DestTy)
 162     : ConstantExpr(DestTy, Instruction::ExtractValue, &Op<0>(), 1),
 163       Indices(IdxList) {
 164     Op<0>() = Agg;
 165   }
 166
 167   /// Indices - These identify which value to extract.
 168   const SmallVector<unsigned, 4> Indices;
 169
 170   /// Transparently provide more efficient getOperand methods.
 171   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 172 };
 173
 174 /// InsertValueConstantExpr - This class is private to
 175 /// Constants.cpp, and is used behind the scenes to implement
 176 /// insertvalue constant exprs.
 177 class InsertValueConstantExpr : public ConstantExpr {
 178   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 179 public:
 180   // allocate space for exactly one operand
 181   void *operator new(size_t s) {
 182     return User::operator new(s, 2);
 183   }
 184   InsertValueConstantExpr(Constant *Agg, Constant *Val,
 185                           const SmallVector<unsigned, 4> &IdxList,
 186                           const Type *DestTy)
 187     : ConstantExpr(DestTy, Instruction::InsertValue, &Op<0>(), 2),
 188       Indices(IdxList) {
 189     Op<0>() = Agg;
 190     Op<1>() = Val;
 191   }
 192
 193   /// Indices - These identify the position for the insertion.
 194   const SmallVector<unsigned, 4> Indices;
 195
 196   /// Transparently provide more efficient getOperand methods.
 197   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 198 };
 199
 200
 201 /// GetElementPtrConstantExpr - This class is private to Constants.cpp, and is
 202 /// used behind the scenes to implement getelementpr constant exprs.
 203 class GetElementPtrConstantExpr : public ConstantExpr {
 204   GetElementPtrConstantExpr(Constant *C, const std::vector<Constant*> &IdxList,
 205                             const Type *DestTy);
 206 public:
 207   static GetElementPtrConstantExpr *Create(Constant *C,
 208                                            const std::vector<Constant*>&IdxList,
 209                                            const Type *DestTy) {
 210     return
 211       new(IdxList.size() + 1) GetElementPtrConstantExpr(C, IdxList, DestTy);
 212   }
 213   /// Transparently provide more efficient getOperand methods.
 214   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 215 };
 216
 217 // CompareConstantExpr - This class is private to Constants.cpp, and is used
 218 // behind the scenes to implement ICmp and FCmp constant expressions. This is
 219 // needed in order to store the predicate value for these instructions.
 220 struct CompareConstantExpr : public ConstantExpr {
 221   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 222   // allocate space for exactly two operands
 223   void *operator new(size_t s) {
 224     return User::operator new(s, 2);
 225   }
 226   unsigned short predicate;
 227   CompareConstantExpr(const Type *ty, Instruction::OtherOps opc,
 228                       unsigned short pred,  Constant* LHS, Constant* RHS)
 229     : ConstantExpr(ty, opc, &Op<0>(), 2), predicate(pred) {
 230     Op<0>() = LHS;
 231     Op<1>() = RHS;
 232   }
 233   /// Transparently provide more efficient getOperand methods.
 234   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 235 };
 236
 237 template <>
 238 struct OperandTraits<UnaryConstantExpr> : FixedNumOperandTraits<1> {
 239 };
 240 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(UnaryConstantExpr, Value)
 241
 242 template <>
 243 struct OperandTraits<BinaryConstantExpr> : FixedNumOperandTraits<2> {
 244 };
 245 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BinaryConstantExpr, Value)
 246
 247 template <>
 248 struct OperandTraits<SelectConstantExpr> : FixedNumOperandTraits<3> {
 249 };
 250 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(SelectConstantExpr, Value)
 251
 252 template <>
 253 struct OperandTraits<ExtractElementConstantExpr> : FixedNumOperandTraits<2> {
 254 };
 255 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractElementConstantExpr, Value)
 256
 257 template <>
 258 struct OperandTraits<InsertElementConstantExpr> : FixedNumOperandTraits<3> {
 259 };
 260 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertElementConstantExpr, Value)
 261
 262 template <>
 263 struct OperandTraits<ShuffleVectorConstantExpr> : FixedNumOperandTraits<3> {
 264 };
 265 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ShuffleVectorConstantExpr, Value)
 266
 267 template <>
 268 struct OperandTraits<ExtractValueConstantExpr> : FixedNumOperandTraits<1> {
 269 };
 270 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractValueConstantExpr, Value)
 271
 272 template <>
 273 struct OperandTraits<InsertValueConstantExpr> : FixedNumOperandTraits<2> {
 274 };
 275 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertValueConstantExpr, Value)
 276
 277 template <>
 278 struct OperandTraits<GetElementPtrConstantExpr> : VariadicOperandTraits<1> {
 279 };
 280
 281 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrConstantExpr, Value)
 282
 283
 284 template <>
 285 struct OperandTraits<CompareConstantExpr> : FixedNumOperandTraits<2> {
 286 };
 287 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CompareConstantExpr, Value)
 288
 289 struct ExprMapKeyType {
 290   typedef SmallVector<unsigned, 4> IndexList;
 291
 292   ExprMapKeyType(unsigned opc,
 293       const std::vector<Constant*> &ops,
 294       unsigned short pred = 0,
 295       const IndexList &inds = IndexList())
 296         : opcode(opc), predicate(pred), operands(ops), indices(inds) {}
 297   uint16_t opcode;
 298   uint16_t predicate;
 299   std::vector<Constant*> operands;
 300   IndexList indices;
 301   bool operator==(const ExprMapKeyType& that) const {
 302     return this->opcode == that.opcode &&
 303            this->predicate == that.predicate &&
 304            this->operands == that.operands &&
 305            this->indices == that.indices;
 306   }
 307   bool operator<(const ExprMapKeyType & that) const {
 308     return this->opcode < that.opcode ||
 309       (this->opcode == that.opcode && this->predicate < that.predicate) ||
 310       (this->opcode == that.opcode && this->predicate == that.predicate &&
 311        this->operands < that.operands) ||
 312       (this->opcode == that.opcode && this->predicate == that.predicate &&
 313        this->operands == that.operands && this->indices < that.indices);
 314   }
 315
 316   bool operator!=(const ExprMapKeyType& that) const {
 317     return !(*this == that);
 318   }
 319 };
 320
 321 // The number of operands for each ConstantCreator::create method is
 322 // determined by the ConstantTraits template.
 323 // ConstantCreator - A class that is used to create constants by
 324 // ValueMap*.  This class should be partially specialized if there is
 325 // something strange that needs to be done to interface to the ctor for the
 326 // constant.
 327 //
 328 template<typename T, typename Alloc>
 329 struct ConstantTraits< std::vector<T, Alloc> > {
 330   static unsigned uses(const std::vector<T, Alloc>& v) {
 331     return v.size();
 332   }
 333 };
 334
 335 template<class ConstantClass, class TypeClass, class ValType>
 336 struct ConstantCreator {
 337   static ConstantClass *create(const TypeClass *Ty, const ValType &V) {
 338     return new(ConstantTraits<ValType>::uses(V)) ConstantClass(Ty, V);
 339   }
 340 };
 341
 342 template<class ConstantClass, class TypeClass>
 343 struct ConvertConstant {
 344   static void convert(ConstantClass *OldC, const TypeClass *NewTy) {
 345     llvm_unreachable("This type cannot be converted!");
 346   }
 347 };
 348
 349 template<>
 350 struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
 351   static ConstantExpr *create(const Type *Ty, const ExprMapKeyType &V,
 352       unsigned short pred = 0) {
 353     if (Instruction::isCast(V.opcode))
 354       return new UnaryConstantExpr(V.opcode, V.operands[0], Ty);
 355     if ((V.opcode >= Instruction::BinaryOpsBegin &&
 356          V.opcode < Instruction::BinaryOpsEnd))
 357       return new BinaryConstantExpr(V.opcode, V.operands[0], V.operands[1]);
 358     if (V.opcode == Instruction::Select)
 359       return new SelectConstantExpr(V.operands[0], V.operands[1],
 360                                     V.operands[2]);
 361     if (V.opcode == Instruction::ExtractElement)
 362       return new ExtractElementConstantExpr(V.operands[0], V.operands[1]);
 363     if (V.opcode == Instruction::InsertElement)
 364       return new InsertElementConstantExpr(V.operands[0], V.operands[1],
 365                                            V.operands[2]);
 366     if (V.opcode == Instruction::ShuffleVector)
 367       return new ShuffleVectorConstantExpr(V.operands[0], V.operands[1],
 368                                            V.operands[2]);
 369     if (V.opcode == Instruction::InsertValue)
 370       return new InsertValueConstantExpr(V.operands[0], V.operands[1],
 371                                          V.indices, Ty);
 372     if (V.opcode == Instruction::ExtractValue)
 373       return new ExtractValueConstantExpr(V.operands[0], V.indices, Ty);
 374     if (V.opcode == Instruction::GetElementPtr) {
 375       std::vector<Constant*> IdxList(V.operands.begin()+1, V.operands.end());
 376       return GetElementPtrConstantExpr::Create(V.operands[0], IdxList, Ty);
 377     }
 378
 379     // The compare instructions are weird. We have to encode the predicate
 380     // value and it is combined with the instruction opcode by multiplying
 381     // the opcode by one hundred. We must decode this to get the predicate.
 382     if (V.opcode == Instruction::ICmp)
 383       return new CompareConstantExpr(Ty, Instruction::ICmp, V.predicate,
 384                                      V.operands[0], V.operands[1]);
 385     if (V.opcode == Instruction::FCmp)
 386       return new CompareConstantExpr(Ty, Instruction::FCmp, V.predicate,
 387                                      V.operands[0], V.operands[1]);
 388     llvm_unreachable("Invalid ConstantExpr!");
 389     return 0;
 390   }
 391 };
 392
 393 template<>
 394 struct ConvertConstant<ConstantExpr, Type> {
 395   static void convert(ConstantExpr *OldC, const Type *NewTy) {
 396     Constant *New;
 397     switch (OldC->getOpcode()) {
 398     case Instruction::Trunc:
 399     case Instruction::ZExt:
 400     case Instruction::SExt:
 401     case Instruction::FPTrunc:
 402     case Instruction::FPExt:
 403     case Instruction::UIToFP:
 404     case Instruction::SIToFP:
 405     case Instruction::FPToUI:
 406     case Instruction::FPToSI:
 407     case Instruction::PtrToInt:
 408     case Instruction::IntToPtr:
 409     case Instruction::BitCast:
 410       New = ConstantExpr::getCast(OldC->getOpcode(), OldC->getOperand(0),
 411                                   NewTy);
 412       break;
 413     case Instruction::Select:
 414       New = ConstantExpr::getSelectTy(NewTy, OldC->getOperand(0),
 415                                       OldC->getOperand(1),
 416                                       OldC->getOperand(2));
 417       break;
 418     default:
 419       assert(OldC->getOpcode() >= Instruction::BinaryOpsBegin &&
 420              OldC->getOpcode() <  Instruction::BinaryOpsEnd);
 421       New = ConstantExpr::getTy(NewTy, OldC->getOpcode(), OldC->getOperand(0),
 422                                 OldC->getOperand(1));
 423       break;
 424     case Instruction::GetElementPtr:
 425       // Make everyone now use a constant of the new type...
 426       std::vector<Value*> Idx(OldC->op_begin()+1, OldC->op_end());
 427       New = ConstantExpr::getGetElementPtrTy(NewTy, OldC->getOperand(0),
 428                                              &Idx[0], Idx.size());
 429       break;
 430     }
 431
 432     assert(New != OldC && "Didn't replace constant??");
 433     OldC->uncheckedReplaceAllUsesWith(New);
 434     OldC->destroyConstant();    // This constant is now dead, destroy it.
 435   }
 436 };
 437
 438 // ConstantAggregateZero does not take extra "value" argument...
 439 template<class ValType>
 440 struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
 441   static ConstantAggregateZero *create(const Type *Ty, const ValType &V){
 442     return new ConstantAggregateZero(Ty);
 443   }
 444 };
 445
 446 template<>
 447 struct ConstantCreator<MDNode, Type, std::vector<Value*> > {
 448   static MDNode *create(const Type* Ty, const std::vector<Value*> &V) {
 449     return new MDNode(Ty->getContext(), &V[0], V.size());
 450   }
 451 };
 452
 453 template<>
 454 struct ConvertConstant<ConstantVector, VectorType> {
 455   static void convert(ConstantVector *OldC, const VectorType *NewTy) {
 456     // Make everyone now use a constant of the new type...
 457     std::vector<Constant*> C;
 458     for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
 459       C.push_back(cast<Constant>(OldC->getOperand(i)));
 460     Constant *New = ConstantVector::get(NewTy, C);
 461     assert(New != OldC && "Didn't replace constant??");
 462     OldC->uncheckedReplaceAllUsesWith(New);
 463     OldC->destroyConstant();    // This constant is now dead, destroy it.
 464   }
 465 };
 466
 467 template<>
 468 struct ConvertConstant<ConstantAggregateZero, Type> {
 469   static void convert(ConstantAggregateZero *OldC, const Type *NewTy) {
 470     // Make everyone now use a constant of the new type...
 471     Constant *New = ConstantAggregateZero::get(NewTy);
 472     assert(New != OldC && "Didn't replace constant??");
 473     OldC->uncheckedReplaceAllUsesWith(New);
 474     OldC->destroyConstant();     // This constant is now dead, destroy it.
 475   }
 476 };
 477
 478 template<>
 479 struct ConvertConstant<ConstantArray, ArrayType> {
 480   static void convert(ConstantArray *OldC, const ArrayType *NewTy) {
 481     // Make everyone now use a constant of the new type...
 482     std::vector<Constant*> C;
 483     for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
 484       C.push_back(cast<Constant>(OldC->getOperand(i)));
 485     Constant *New = ConstantArray::get(NewTy, C);
 486     assert(New != OldC && "Didn't replace constant??");
 487     OldC->uncheckedReplaceAllUsesWith(New);
 488     OldC->destroyConstant();    // This constant is now dead, destroy it.
 489   }
 490 };
 491
 492 template<>
 493 struct ConvertConstant<ConstantStruct, StructType> {
 494   static void convert(ConstantStruct *OldC, const StructType *NewTy) {
 495     // Make everyone now use a constant of the new type...
 496     std::vector<Constant*> C;
 497     for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
 498       C.push_back(cast<Constant>(OldC->getOperand(i)));
 499     Constant *New = ConstantStruct::get(NewTy, C);
 500     assert(New != OldC && "Didn't replace constant??");
 501
 502     OldC->uncheckedReplaceAllUsesWith(New);
 503     OldC->destroyConstant();    // This constant is now dead, destroy it.
 504   }
 505 };
 506
 507 // ConstantPointerNull does not take extra "value" argument...
 508 template<class ValType>
 509 struct ConstantCreator<ConstantPointerNull, PointerType, ValType> {
 510   static ConstantPointerNull *create(const PointerType *Ty, const ValType &V){
 511     return new ConstantPointerNull(Ty);
 512   }
 513 };
 514
 515 template<>
 516 struct ConvertConstant<ConstantPointerNull, PointerType> {
 517   static void convert(ConstantPointerNull *OldC, const PointerType *NewTy) {
 518     // Make everyone now use a constant of the new type...
 519     Constant *New = ConstantPointerNull::get(NewTy);
 520     assert(New != OldC && "Didn't replace constant??");
 521     OldC->uncheckedReplaceAllUsesWith(New);
 522     OldC->destroyConstant();     // This constant is now dead, destroy it.
 523   }
 524 };
 525
 526 // UndefValue does not take extra "value" argument...
 527 template<class ValType>
 528 struct ConstantCreator<UndefValue, Type, ValType> {
 529   static UndefValue *create(const Type *Ty, const ValType &V) {
 530     return new UndefValue(Ty);
 531   }
 532 };
 533
 534 template<>
 535 struct ConvertConstant<UndefValue, Type> {
 536   static void convert(UndefValue *OldC, const Type *NewTy) {
 537     // Make everyone now use a constant of the new type.
 538     Constant *New = UndefValue::get(NewTy);
 539     assert(New != OldC && "Didn't replace constant??");
 540     OldC->uncheckedReplaceAllUsesWith(New);
 541     OldC->destroyConstant();     // This constant is now dead, destroy it.
 542   }
 543 };
 544
 545 template<class ValType, class TypeClass, class ConstantClass,
 546          bool HasLargeKey = false /*true for arrays and structs*/ >
 547 class ValueMap : public AbstractTypeUser {
 548 public:
 549   typedef std::pair<const Type*, ValType> MapKey;
 550   typedef std::map<MapKey, Value *> MapTy;
 551   typedef std::map<Value*, typename MapTy::iterator> InverseMapTy;
 552   typedef std::map<const Type*, typename MapTy::iterator> AbstractTypeMapTy;
 553 private:
 554   /// Map - This is the main map from the element descriptor to the Constants.
 555   /// This is the primary way we avoid creating two of the same shape
 556   /// constant.
 557   MapTy Map;
 558
 559   /// InverseMap - If "HasLargeKey" is true, this contains an inverse mapping
 560   /// from the constants to their element in Map.  This is important for
 561   /// removal of constants from the array, which would otherwise have to scan
 562   /// through the map with very large keys.
 563   InverseMapTy InverseMap;
 564
 565   /// AbstractTypeMap - Map for abstract type constants.
 566   ///
 567   AbstractTypeMapTy AbstractTypeMap;
 568
 569   /// ValueMapLock - Mutex for this map.
 570   sys::SmartMutex<true> ValueMapLock;
 571
 572 public:
 573   // NOTE: This function is not locked.  It is the caller's responsibility
 574   // to enforce proper synchronization.
 575   typename MapTy::iterator map_begin() { return Map.begin(); }
 576   typename MapTy::iterator map_end() { return Map.end(); }
 577
 578   /// InsertOrGetItem - Return an iterator for the specified element.
 579   /// If the element exists in the map, the returned iterator points to the
 580   /// entry and Exists=true.  If not, the iterator points to the newly
 581   /// inserted entry and returns Exists=false.  Newly inserted entries have
 582   /// I->second == 0, and should be filled in.
 583   /// NOTE: This function is not locked.  It is the caller's responsibility
 584   // to enforce proper synchronization.
 585   typename MapTy::iterator InsertOrGetItem(std::pair<MapKey, Constant *>
 586                                  &InsertVal,
 587                                  bool &Exists) {
 588     std::pair<typename MapTy::iterator, bool> IP = Map.insert(InsertVal);
 589     Exists = !IP.second;
 590     return IP.first;
 591   }
 592
 593 private:
 594   typename MapTy::iterator FindExistingElement(ConstantClass *CP) {
 595     if (HasLargeKey) {
 596       typename InverseMapTy::iterator IMI = InverseMap.find(CP);
 597       assert(IMI != InverseMap.end() && IMI->second != Map.end() &&
 598              IMI->second->second == CP &&
 599              "InverseMap corrupt!");
 600       return IMI->second;
 601     }
 602
 603     typename MapTy::iterator I =
 604       Map.find(MapKey(static_cast<const TypeClass*>(CP->getRawType()),
 605                       getValType(CP)));
 606     if (I == Map.end() || I->second != CP) {
 607       // FIXME: This should not use a linear scan.  If this gets to be a
 608       // performance problem, someone should look at this.
 609       for (I = Map.begin(); I != Map.end() && I->second != CP; ++I)
 610         /* empty */;
 611     }
 612     return I;
 613   }
 614
 615   ConstantClass* Create(const TypeClass *Ty, const ValType &V,
 616                         typename MapTy::iterator I) {
 617     ConstantClass* Result =
 618       ConstantCreator<ConstantClass,TypeClass,ValType>::create(Ty, V);
 619
 620     assert(Result->getType() == Ty && "Type specified is not correct!");
 621     I = Map.insert(I, std::make_pair(MapKey(Ty, V), Result));
 622
 623     if (HasLargeKey)  // Remember the reverse mapping if needed.
 624       InverseMap.insert(std::make_pair(Result, I));
 625
 626     // If the type of the constant is abstract, make sure that an entry
 627     // exists for it in the AbstractTypeMap.
 628     if (Ty->isAbstract()) {
 629       typename AbstractTypeMapTy::iterator TI =
 630                                                AbstractTypeMap.find(Ty);
 631
 632       if (TI == AbstractTypeMap.end()) {
 633         // Add ourselves to the ATU list of the type.
 634         cast<DerivedType>(Ty)->addAbstractTypeUser(this);
 635
 636         AbstractTypeMap.insert(TI, std::make_pair(Ty, I));
 637       }
 638     }
 639
 640     return Result;
 641   }
 642 public:
 643
 644   /// getOrCreate - Return the specified constant from the map, creating it if
 645   /// necessary.
 646   ConstantClass *getOrCreate(const TypeClass *Ty, const ValType &V) {
 647     sys::SmartScopedLock<true> Lock(ValueMapLock);
 648     MapKey Lookup(Ty, V);
 649     ConstantClass* Result = 0;
 650
 651     typename MapTy::iterator I = Map.find(Lookup);
 652     // Is it in the map?
 653     if (I != Map.end())
 654       Result = static_cast<ConstantClass *>(I->second);
 655
 656     if (!Result) {
 657       // If no preexisting value, create one now...
 658       Result = Create(Ty, V, I);
 659     }
 660
 661     return Result;
 662   }
 663
 664   void remove(ConstantClass *CP) {
 665     sys::SmartScopedLock<true> Lock(ValueMapLock);
 666     typename MapTy::iterator I = FindExistingElement(CP);
 667     assert(I != Map.end() && "Constant not found in constant table!");
 668     assert(I->second == CP && "Didn't find correct element?");
 669
 670     if (HasLargeKey)  // Remember the reverse mapping if needed.
 671       InverseMap.erase(CP);
 672
 673     // Now that we found the entry, make sure this isn't the entry that
 674     // the AbstractTypeMap points to.
 675     const TypeClass *Ty = static_cast<const TypeClass *>(I->first.first);
 676     if (Ty->isAbstract()) {
 677       assert(AbstractTypeMap.count(Ty) &&
 678              "Abstract type not in AbstractTypeMap?");
 679       typename MapTy::iterator &ATMEntryIt = AbstractTypeMap[Ty];
 680       if (ATMEntryIt == I) {
 681         // Yes, we are removing the representative entry for this type.
 682         // See if there are any other entries of the same type.
 683         typename MapTy::iterator TmpIt = ATMEntryIt;
 684
 685         // First check the entry before this one...
 686         if (TmpIt != Map.begin()) {
 687           --TmpIt;
 688           if (TmpIt->first.first != Ty) // Not the same type, move back...
 689             ++TmpIt;
 690         }
 691
 692         // If we didn't find the same type, try to move forward...
 693         if (TmpIt == ATMEntryIt) {
 694           ++TmpIt;
 695           if (TmpIt == Map.end() || TmpIt->first.first != Ty)
 696             --TmpIt;   // No entry afterwards with the same type
 697         }
 698
 699         // If there is another entry in the map of the same abstract type,
 700         // update the AbstractTypeMap entry now.
 701         if (TmpIt != ATMEntryIt) {
 702           ATMEntryIt = TmpIt;
 703         } else {
 704           // Otherwise, we are removing the last instance of this type
 705           // from the table.  Remove from the ATM, and from user list.
 706           cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
 707           AbstractTypeMap.erase(Ty);
 708         }
 709       }
 710     }
 711
 712     Map.erase(I);
 713   }
 714
 715
 716   /// MoveConstantToNewSlot - If we are about to change C to be the element
 717   /// specified by I, update our internal data structures to reflect this
 718   /// fact.
 719   /// NOTE: This function is not locked. It is the responsibility of the
 720   /// caller to enforce proper synchronization if using this method.
 721   void MoveConstantToNewSlot(ConstantClass *C, typename MapTy::iterator I) {
 722     // First, remove the old location of the specified constant in the map.
 723     typename MapTy::iterator OldI = FindExistingElement(C);
 724     assert(OldI != Map.end() && "Constant not found in constant table!");
 725     assert(OldI->second == C && "Didn't find correct element?");
 726
 727     // If this constant is the representative element for its abstract type,
 728     // update the AbstractTypeMap so that the representative element is I.
 729     if (C->getType()->isAbstract()) {
 730       typename AbstractTypeMapTy::iterator ATI =
 731           AbstractTypeMap.find(C->getType());
 732       assert(ATI != AbstractTypeMap.end() &&
 733              "Abstract type not in AbstractTypeMap?");
 734       if (ATI->second == OldI)
 735         ATI->second = I;
 736     }
 737
 738     // Remove the old entry from the map.
 739     Map.erase(OldI);
 740
 741     // Update the inverse map so that we know that this constant is now
 742     // located at descriptor I.
 743     if (HasLargeKey) {
 744       assert(I->second == C && "Bad inversemap entry!");
 745       InverseMap[C] = I;
 746     }
 747   }
 748
 749   void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
 750     sys::SmartScopedLock<true> Lock(ValueMapLock);
 751     typename AbstractTypeMapTy::iterator I =
 752       AbstractTypeMap.find(cast<Type>(OldTy));
 753
 754     assert(I != AbstractTypeMap.end() &&
 755            "Abstract type not in AbstractTypeMap?");
 756
 757     // Convert a constant at a time until the last one is gone.  The last one
 758     // leaving will remove() itself, causing the AbstractTypeMapEntry to be
 759     // eliminated eventually.
 760     do {
 761       ConvertConstant<ConstantClass, TypeClass>::convert(
 762                               static_cast<ConstantClass *>(I->second->second),
 763                                               cast<TypeClass>(NewTy));
 764
 765       I = AbstractTypeMap.find(cast<Type>(OldTy));
 766     } while (I != AbstractTypeMap.end());
 767   }
 768
 769   // If the type became concrete without being refined to any other existing
 770   // type, we just remove ourselves from the ATU list.
 771   void typeBecameConcrete(const DerivedType *AbsTy) {
 772     AbsTy->removeAbstractTypeUser(this);
 773   }
 774
 775   void dump() const {
 776     DOUT << "Constant.cpp: ValueMap\n";
 777   }
 778 };
 779
 780 }
 781
 782 #endif