lib/VMCore/ConstantsContext.h

   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_CONSTANTSCONTEXT_H
  16 #define LLVM_CONSTANTSCONTEXT_H
  17
  18 #include "llvm/Instructions.h"
  19 #include "llvm/Operator.h"
  20 #include "llvm/Support/Debug.h"
  21 #include "llvm/Support/ErrorHandling.h"
  22 #include "llvm/Support/raw_ostream.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                      unsigned Flags)
  58     : ConstantExpr(C1->getType(), Opcode, &Op<0>(), 2) {
  59     Op<0>() = C1;
  60     Op<1>() = C2;
  61     SubclassOptionalData = Flags;
  62   }
  63   /// Transparently provide more efficient getOperand methods.
  64   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
  65 };
  66
  67 /// SelectConstantExpr - This class is private to Constants.cpp, and is used
  68 /// behind the scenes to implement select constant exprs.
  69 class SelectConstantExpr : public ConstantExpr {
  70   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  71 public:
  72   // allocate space for exactly three operands
  73   void *operator new(size_t s) {
  74     return User::operator new(s, 3);
  75   }
  76   SelectConstantExpr(Constant *C1, Constant *C2, Constant *C3)
  77     : ConstantExpr(C2->getType(), Instruction::Select, &Op<0>(), 3) {
  78     Op<0>() = C1;
  79     Op<1>() = C2;
  80     Op<2>() = C3;
  81   }
  82   /// Transparently provide more efficient getOperand methods.
  83   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
  84 };
  85
  86 /// ExtractElementConstantExpr - This class is private to
  87 /// Constants.cpp, and is used behind the scenes to implement
  88 /// extractelement constant exprs.
  89 class ExtractElementConstantExpr : public ConstantExpr {
  90   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  91 public:
  92   // allocate space for exactly two operands
  93   void *operator new(size_t s) {
  94     return User::operator new(s, 2);
  95   }
  96   ExtractElementConstantExpr(Constant *C1, Constant *C2)
  97     : ConstantExpr(cast<VectorType>(C1->getType())->getElementType(),
  98                    Instruction::ExtractElement, &Op<0>(), 2) {
  99     Op<0>() = C1;
 100     Op<1>() = C2;
 101   }
 102   /// Transparently provide more efficient getOperand methods.
 103   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 104 };
 105
 106 /// InsertElementConstantExpr - This class is private to
 107 /// Constants.cpp, and is used behind the scenes to implement
 108 /// insertelement constant exprs.
 109 class InsertElementConstantExpr : public ConstantExpr {
 110   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 111 public:
 112   // allocate space for exactly three operands
 113   void *operator new(size_t s) {
 114     return User::operator new(s, 3);
 115   }
 116   InsertElementConstantExpr(Constant *C1, Constant *C2, Constant *C3)
 117     : ConstantExpr(C1->getType(), Instruction::InsertElement,
 118                    &Op<0>(), 3) {
 119     Op<0>() = C1;
 120     Op<1>() = C2;
 121     Op<2>() = C3;
 122   }
 123   /// Transparently provide more efficient getOperand methods.
 124   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 125 };
 126
 127 /// ShuffleVectorConstantExpr - This class is private to
 128 /// Constants.cpp, and is used behind the scenes to implement
 129 /// shufflevector constant exprs.
 130 class ShuffleVectorConstantExpr : public ConstantExpr {
 131   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 132 public:
 133   // allocate space for exactly three operands
 134   void *operator new(size_t s) {
 135     return User::operator new(s, 3);
 136   }
 137   ShuffleVectorConstantExpr(Constant *C1, Constant *C2, Constant *C3)
 138   : ConstantExpr(VectorType::get(
 139                    cast<VectorType>(C1->getType())->getElementType(),
 140                    cast<VectorType>(C3->getType())->getNumElements()),
 141                  Instruction::ShuffleVector,
 142                  &Op<0>(), 3) {
 143     Op<0>() = C1;
 144     Op<1>() = C2;
 145     Op<2>() = C3;
 146   }
 147   /// Transparently provide more efficient getOperand methods.
 148   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 149 };
 150
 151 /// ExtractValueConstantExpr - This class is private to
 152 /// Constants.cpp, and is used behind the scenes to implement
 153 /// extractvalue constant exprs.
 154 class ExtractValueConstantExpr : public ConstantExpr {
 155   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 156 public:
 157   // allocate space for exactly one operand
 158   void *operator new(size_t s) {
 159     return User::operator new(s, 1);
 160   }
 161   ExtractValueConstantExpr(Constant *Agg,
 162                            const SmallVector<unsigned, 4> &IdxList,
 163                            const Type *DestTy)
 164     : ConstantExpr(DestTy, Instruction::ExtractValue, &Op<0>(), 1),
 165       Indices(IdxList) {
 166     Op<0>() = Agg;
 167   }
 168
 169   /// Indices - These identify which value to extract.
 170   const SmallVector<unsigned, 4> Indices;
 171
 172   /// Transparently provide more efficient getOperand methods.
 173   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 174 };
 175
 176 /// InsertValueConstantExpr - This class is private to
 177 /// Constants.cpp, and is used behind the scenes to implement
 178 /// insertvalue constant exprs.
 179 class InsertValueConstantExpr : public ConstantExpr {
 180   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 181 public:
 182   // allocate space for exactly one operand
 183   void *operator new(size_t s) {
 184     return User::operator new(s, 2);
 185   }
 186   InsertValueConstantExpr(Constant *Agg, Constant *Val,
 187                           const SmallVector<unsigned, 4> &IdxList,
 188                           const Type *DestTy)
 189     : ConstantExpr(DestTy, Instruction::InsertValue, &Op<0>(), 2),
 190       Indices(IdxList) {
 191     Op<0>() = Agg;
 192     Op<1>() = Val;
 193   }
 194
 195   /// Indices - These identify the position for the insertion.
 196   const SmallVector<unsigned, 4> Indices;
 197
 198   /// Transparently provide more efficient getOperand methods.
 199   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 200 };
 201
 202
 203 /// GetElementPtrConstantExpr - This class is private to Constants.cpp, and is
 204 /// used behind the scenes to implement getelementpr constant exprs.
 205 class GetElementPtrConstantExpr : public ConstantExpr {
 206   GetElementPtrConstantExpr(Constant *C, const std::vector<Constant*> &IdxList,
 207                             const Type *DestTy);
 208 public:
 209   static GetElementPtrConstantExpr *Create(Constant *C,
 210                                            const std::vector<Constant*>&IdxList,
 211                                            const Type *DestTy,
 212                                            unsigned Flags) {
 213     GetElementPtrConstantExpr *Result =
 214       new(IdxList.size() + 1) GetElementPtrConstantExpr(C, IdxList, DestTy);
 215     Result->SubclassOptionalData = Flags;
 216     return Result;
 217   }
 218   /// Transparently provide more efficient getOperand methods.
 219   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 220 };
 221
 222 // CompareConstantExpr - This class is private to Constants.cpp, and is used
 223 // behind the scenes to implement ICmp and FCmp constant expressions. This is
 224 // needed in order to store the predicate value for these instructions.
 225 struct CompareConstantExpr : public ConstantExpr {
 226   void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
 227   // allocate space for exactly two operands
 228   void *operator new(size_t s) {
 229     return User::operator new(s, 2);
 230   }
 231   unsigned short predicate;
 232   CompareConstantExpr(const Type *ty, Instruction::OtherOps opc,
 233                       unsigned short pred,  Constant* LHS, Constant* RHS)
 234     : ConstantExpr(ty, opc, &Op<0>(), 2), predicate(pred) {
 235     Op<0>() = LHS;
 236     Op<1>() = RHS;
 237   }
 238   /// Transparently provide more efficient getOperand methods.
 239   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
 240 };
 241
 242 template <>
 243 struct OperandTraits<UnaryConstantExpr> : public FixedNumOperandTraits<1> {
 244 };
 245 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(UnaryConstantExpr, Value)
 246
 247 template <>
 248 struct OperandTraits<BinaryConstantExpr> : public FixedNumOperandTraits<2> {
 249 };
 250 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BinaryConstantExpr, Value)
 251
 252 template <>
 253 struct OperandTraits<SelectConstantExpr> : public FixedNumOperandTraits<3> {
 254 };
 255 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(SelectConstantExpr, Value)
 256
 257 template <>
 258 struct OperandTraits<ExtractElementConstantExpr> : public FixedNumOperandTraits<2> {
 259 };
 260 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractElementConstantExpr, Value)
 261
 262 template <>
 263 struct OperandTraits<InsertElementConstantExpr> : public FixedNumOperandTraits<3> {
 264 };
 265 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertElementConstantExpr, Value)
 266
 267 template <>
 268 struct OperandTraits<ShuffleVectorConstantExpr> : public FixedNumOperandTraits<3> {
 269 };
 270 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ShuffleVectorConstantExpr, Value)
 271
 272 template <>
 273 struct OperandTraits<ExtractValueConstantExpr> : public FixedNumOperandTraits<1> {
 274 };
 275 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractValueConstantExpr, Value)
 276
 277 template <>
 278 struct OperandTraits<InsertValueConstantExpr> : public FixedNumOperandTraits<2> {
 279 };
 280 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertValueConstantExpr, Value)
 281
 282 template <>
 283 struct OperandTraits<GetElementPtrConstantExpr> : public VariadicOperandTraits<1> {
 284 };
 285
 286 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrConstantExpr, Value)
 287
 288
 289 template <>
 290 struct OperandTraits<CompareConstantExpr> : public FixedNumOperandTraits<2> {
 291 };
 292 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CompareConstantExpr, Value)
 293
 294 struct ExprMapKeyType {
 295   typedef SmallVector<unsigned, 4> IndexList;
 296
 297   ExprMapKeyType(unsigned opc,
 298       const std::vector<Constant*> &ops,
 299       unsigned short flags = 0,
 300       unsigned short optionalflags = 0,
 301       const IndexList &inds = IndexList())
 302         : opcode(opc), subclassoptionaldata(optionalflags), subclassdata(flags),
 303         operands(ops), indices(inds) {}
 304   uint8_t opcode;
 305   uint8_t subclassoptionaldata;
 306   uint16_t subclassdata;
 307   std::vector<Constant*> operands;
 308   IndexList indices;
 309   bool operator==(const ExprMapKeyType& that) const {
 310     return this->opcode == that.opcode &&
 311            this->subclassdata == that.subclassdata &&
 312            this->subclassoptionaldata == that.subclassoptionaldata &&
 313            this->operands == that.operands &&
 314            this->indices == that.indices;
 315   }
 316   bool operator<(const ExprMapKeyType & that) const {
 317     if (this->opcode != that.opcode) return this->opcode < that.opcode;
 318     if (this->operands != that.operands) return this->operands < that.operands;
 319     if (this->subclassdata != that.subclassdata)
 320       return this->subclassdata < that.subclassdata;
 321     if (this->subclassoptionaldata != that.subclassoptionaldata)
 322       return this->subclassoptionaldata < that.subclassoptionaldata;
 323     if (this->indices != that.indices) return this->indices < that.indices;
 324     return false;
 325   }
 326
 327   bool operator!=(const ExprMapKeyType& that) const {
 328     return !(*this == that);
 329   }
 330 };
 331
 332 // The number of operands for each ConstantCreator::create method is
 333 // determined by the ConstantTraits template.
 334 // ConstantCreator - A class that is used to create constants by
 335 // ValueMap*.  This class should be partially specialized if there is
 336 // something strange that needs to be done to interface to the ctor for the
 337 // constant.
 338 //
 339 template<typename T, typename Alloc>
 340 struct ConstantTraits< std::vector<T, Alloc> > {
 341   static unsigned uses(const std::vector<T, Alloc>& v) {
 342     return v.size();
 343   }
 344 };
 345
 346 template<class ConstantClass, class TypeClass, class ValType>
 347 struct ConstantCreator {
 348   static ConstantClass *create(const TypeClass *Ty, const ValType &V) {
 349     return new(ConstantTraits<ValType>::uses(V)) ConstantClass(Ty, V);
 350   }
 351 };
 352
 353 template<class ConstantClass>
 354 struct ConstantKeyData {
 355   typedef void ValType;
 356   static ValType getValType(ConstantClass *C) {
 357     llvm_unreachable("Unknown Constant type!");
 358   }
 359 };
 360
 361 template<>
 362 struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
 363   static ConstantExpr *create(const Type *Ty, const ExprMapKeyType &V,
 364       unsigned short pred = 0) {
 365     if (Instruction::isCast(V.opcode))
 366       return new UnaryConstantExpr(V.opcode, V.operands[0], Ty);
 367     if ((V.opcode >= Instruction::BinaryOpsBegin &&
 368          V.opcode < Instruction::BinaryOpsEnd))
 369       return new BinaryConstantExpr(V.opcode, V.operands[0], V.operands[1],
 370                                     V.subclassoptionaldata);
 371     if (V.opcode == Instruction::Select)
 372       return new SelectConstantExpr(V.operands[0], V.operands[1],
 373                                     V.operands[2]);
 374     if (V.opcode == Instruction::ExtractElement)
 375       return new ExtractElementConstantExpr(V.operands[0], V.operands[1]);
 376     if (V.opcode == Instruction::InsertElement)
 377       return new InsertElementConstantExpr(V.operands[0], V.operands[1],
 378                                            V.operands[2]);
 379     if (V.opcode == Instruction::ShuffleVector)
 380       return new ShuffleVectorConstantExpr(V.operands[0], V.operands[1],
 381                                            V.operands[2]);
 382     if (V.opcode == Instruction::InsertValue)
 383       return new InsertValueConstantExpr(V.operands[0], V.operands[1],
 384                                          V.indices, Ty);
 385     if (V.opcode == Instruction::ExtractValue)
 386       return new ExtractValueConstantExpr(V.operands[0], V.indices, Ty);
 387     if (V.opcode == Instruction::GetElementPtr) {
 388       std::vector<Constant*> IdxList(V.operands.begin()+1, V.operands.end());
 389       return GetElementPtrConstantExpr::Create(V.operands[0], IdxList, Ty,
 390                                                V.subclassoptionaldata);
 391     }
 392
 393     // The compare instructions are weird. We have to encode the predicate
 394     // value and it is combined with the instruction opcode by multiplying
 395     // the opcode by one hundred. We must decode this to get the predicate.
 396     if (V.opcode == Instruction::ICmp)
 397       return new CompareConstantExpr(Ty, Instruction::ICmp, V.subclassdata,
 398                                      V.operands[0], V.operands[1]);
 399     if (V.opcode == Instruction::FCmp)
 400       return new CompareConstantExpr(Ty, Instruction::FCmp, V.subclassdata,
 401                                      V.operands[0], V.operands[1]);
 402     llvm_unreachable("Invalid ConstantExpr!");
 403     return 0;
 404   }
 405 };
 406
 407 template<>
 408 struct ConstantKeyData<ConstantExpr> {
 409   typedef ExprMapKeyType ValType;
 410   static ValType getValType(ConstantExpr *CE) {
 411     std::vector<Constant*> Operands;
 412     Operands.reserve(CE->getNumOperands());
 413     for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
 414       Operands.push_back(cast<Constant>(CE->getOperand(i)));
 415     return ExprMapKeyType(CE->getOpcode(), Operands,
 416         CE->isCompare() ? CE->getPredicate() : 0,
 417         CE->getRawSubclassOptionalData(),
 418         CE->hasIndices() ?
 419           CE->getIndices() : SmallVector<unsigned, 4>());
 420   }
 421 };
 422
 423 // ConstantAggregateZero does not take extra "value" argument...
 424 template<class ValType>
 425 struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
 426   static ConstantAggregateZero *create(const Type *Ty, const ValType &V){
 427     return new ConstantAggregateZero(Ty);
 428   }
 429 };
 430
 431 template<>
 432 struct ConstantKeyData<ConstantVector> {
 433   typedef std::vector<Constant*> ValType;
 434   static ValType getValType(ConstantVector *CP) {
 435     std::vector<Constant*> Elements;
 436     Elements.reserve(CP->getNumOperands());
 437     for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
 438       Elements.push_back(CP->getOperand(i));
 439     return Elements;
 440   }
 441 };
 442
 443 template<>
 444 struct ConstantKeyData<ConstantAggregateZero> {
 445   typedef char ValType;
 446   static ValType getValType(ConstantAggregateZero *C) {
 447     return 0;
 448   }
 449 };
 450
 451 template<>
 452 struct ConstantKeyData<ConstantArray> {
 453   typedef std::vector<Constant*> ValType;
 454   static ValType getValType(ConstantArray *CA) {
 455     std::vector<Constant*> Elements;
 456     Elements.reserve(CA->getNumOperands());
 457     for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
 458       Elements.push_back(cast<Constant>(CA->getOperand(i)));
 459     return Elements;
 460   }
 461 };
 462
 463 template<>
 464 struct ConstantKeyData<ConstantStruct> {
 465   typedef std::vector<Constant*> ValType;
 466   static ValType getValType(ConstantStruct *CS) {
 467     std::vector<Constant*> Elements;
 468     Elements.reserve(CS->getNumOperands());
 469     for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i)
 470       Elements.push_back(cast<Constant>(CS->getOperand(i)));
 471     return Elements;
 472   }
 473 };
 474
 475 // ConstantPointerNull does not take extra "value" argument...
 476 template<class ValType>
 477 struct ConstantCreator<ConstantPointerNull, PointerType, ValType> {
 478   static ConstantPointerNull *create(const PointerType *Ty, const ValType &V){
 479     return new ConstantPointerNull(Ty);
 480   }
 481 };
 482
 483 template<>
 484 struct ConstantKeyData<ConstantPointerNull> {
 485   typedef char ValType;
 486   static ValType getValType(ConstantPointerNull *C) {
 487     return 0;
 488   }
 489 };
 490
 491 // UndefValue does not take extra "value" argument...
 492 template<class ValType>
 493 struct ConstantCreator<UndefValue, Type, ValType> {
 494   static UndefValue *create(const Type *Ty, const ValType &V) {
 495     return new UndefValue(Ty);
 496   }
 497 };
 498
 499 template<>
 500 struct ConstantKeyData<UndefValue> {
 501   typedef char ValType;
 502   static ValType getValType(UndefValue *C) {
 503     return 0;
 504   }
 505 };
 506
 507 template<class ValType, class TypeClass, class ConstantClass,
 508          bool HasLargeKey = false /*true for arrays and structs*/ >
 509 class ValueMap : public AbstractTypeUser {
 510 public:
 511   typedef std::pair<const TypeClass*, ValType> MapKey;
 512   typedef std::map<MapKey, ConstantClass *> MapTy;
 513   typedef std::map<ConstantClass *, typename MapTy::iterator> InverseMapTy;
 514   typedef std::map<const DerivedType*, typename MapTy::iterator>
 515     AbstractTypeMapTy;
 516 private:
 517   /// Map - This is the main map from the element descriptor to the Constants.
 518   /// This is the primary way we avoid creating two of the same shape
 519   /// constant.
 520   MapTy Map;
 521
 522   /// InverseMap - If "HasLargeKey" is true, this contains an inverse mapping
 523   /// from the constants to their element in Map.  This is important for
 524   /// removal of constants from the array, which would otherwise have to scan
 525   /// through the map with very large keys.
 526   InverseMapTy InverseMap;
 527
 528   /// AbstractTypeMap - Map for abstract type constants.
 529   ///
 530   AbstractTypeMapTy AbstractTypeMap;
 531
 532   /// ValueMapLock - Mutex for this map.
 533   sys::SmartMutex<true> ValueMapLock;
 534
 535 public:
 536   // NOTE: This function is not locked.  It is the caller's responsibility
 537   // to enforce proper synchronization.
 538   typename MapTy::iterator map_begin() { return Map.begin(); }
 539   typename MapTy::iterator map_end() { return Map.end(); }
 540
 541   void freeConstants() {
 542     for (typename MapTy::iterator I=Map.begin(), E=Map.end();
 543          I != E; ++I) {
 544       if (I->second->use_empty())
 545         delete I->second;
 546     }
 547   }
 548
 549   /// InsertOrGetItem - Return an iterator for the specified element.
 550   /// If the element exists in the map, the returned iterator points to the
 551   /// entry and Exists=true.  If not, the iterator points to the newly
 552   /// inserted entry and returns Exists=false.  Newly inserted entries have
 553   /// I->second == 0, and should be filled in.
 554   /// NOTE: This function is not locked.  It is the caller's responsibility
 555   // to enforce proper synchronization.
 556   typename MapTy::iterator InsertOrGetItem(std::pair<MapKey, ConstantClass *>
 557                                  &InsertVal,
 558                                  bool &Exists) {
 559     std::pair<typename MapTy::iterator, bool> IP = Map.insert(InsertVal);
 560     Exists = !IP.second;
 561     return IP.first;
 562   }
 563
 564 private:
 565   typename MapTy::iterator FindExistingElement(ConstantClass *CP) {
 566     if (HasLargeKey) {
 567       typename InverseMapTy::iterator IMI = InverseMap.find(CP);
 568       assert(IMI != InverseMap.end() && IMI->second != Map.end() &&
 569              IMI->second->second == CP &&
 570              "InverseMap corrupt!");
 571       return IMI->second;
 572     }
 573
 574     typename MapTy::iterator I =
 575       Map.find(MapKey(static_cast<const TypeClass*>(CP->getRawType()),
 576                       ConstantKeyData<ConstantClass>::getValType(CP)));
 577     if (I == Map.end() || I->second != CP) {
 578       // FIXME: This should not use a linear scan.  If this gets to be a
 579       // performance problem, someone should look at this.
 580       for (I = Map.begin(); I != Map.end() && I->second != CP; ++I)
 581         /* empty */;
 582     }
 583     return I;
 584   }
 585
 586   void AddAbstractTypeUser(const Type *Ty, typename MapTy::iterator I) {
 587     // If the type of the constant is abstract, make sure that an entry
 588     // exists for it in the AbstractTypeMap.
 589     if (Ty->isAbstract()) {
 590       const DerivedType *DTy = static_cast<const DerivedType *>(Ty);
 591       typename AbstractTypeMapTy::iterator TI = AbstractTypeMap.find(DTy);
 592
 593       if (TI == AbstractTypeMap.end()) {
 594         // Add ourselves to the ATU list of the type.
 595         cast<DerivedType>(DTy)->addAbstractTypeUser(this);
 596
 597         AbstractTypeMap.insert(TI, std::make_pair(DTy, I));
 598       }
 599     }
 600   }
 601
 602   ConstantClass* Create(const TypeClass *Ty, const ValType &V,
 603                         typename MapTy::iterator I) {
 604     ConstantClass* Result =
 605       ConstantCreator<ConstantClass,TypeClass,ValType>::create(Ty, V);
 606
 607     assert(Result->getType() == Ty && "Type specified is not correct!");
 608     I = Map.insert(I, std::make_pair(MapKey(Ty, V), Result));
 609
 610     if (HasLargeKey)  // Remember the reverse mapping if needed.
 611       InverseMap.insert(std::make_pair(Result, I));
 612
 613     AddAbstractTypeUser(Ty, I);
 614
 615     return Result;
 616   }
 617 public:
 618
 619   /// getOrCreate - Return the specified constant from the map, creating it if
 620   /// necessary.
 621   ConstantClass *getOrCreate(const TypeClass *Ty, const ValType &V) {
 622     sys::SmartScopedLock<true> Lock(ValueMapLock);
 623     MapKey Lookup(Ty, V);
 624     ConstantClass* Result = 0;
 625
 626     typename MapTy::iterator I = Map.find(Lookup);
 627     // Is it in the map?
 628     if (I != Map.end())
 629       Result = I->second;
 630
 631     if (!Result) {
 632       // If no preexisting value, create one now...
 633       Result = Create(Ty, V, I);
 634     }
 635
 636     return Result;
 637   }
 638
 639   void UpdateAbstractTypeMap(const DerivedType *Ty,
 640                              typename MapTy::iterator I) {
 641     assert(AbstractTypeMap.count(Ty) &&
 642            "Abstract type not in AbstractTypeMap?");
 643     typename MapTy::iterator &ATMEntryIt = AbstractTypeMap[Ty];
 644     if (ATMEntryIt == I) {
 645       // Yes, we are removing the representative entry for this type.
 646       // See if there are any other entries of the same type.
 647       typename MapTy::iterator TmpIt = ATMEntryIt;
 648
 649       // First check the entry before this one...
 650       if (TmpIt != Map.begin()) {
 651         --TmpIt;
 652         if (TmpIt->first.first != Ty) // Not the same type, move back...
 653           ++TmpIt;
 654       }
 655
 656       // If we didn't find the same type, try to move forward...
 657       if (TmpIt == ATMEntryIt) {
 658         ++TmpIt;
 659         if (TmpIt == Map.end() || TmpIt->first.first != Ty)
 660           --TmpIt;   // No entry afterwards with the same type
 661       }
 662
 663       // If there is another entry in the map of the same abstract type,
 664       // update the AbstractTypeMap entry now.
 665       if (TmpIt != ATMEntryIt) {
 666         ATMEntryIt = TmpIt;
 667       } else {
 668         // Otherwise, we are removing the last instance of this type
 669         // from the table.  Remove from the ATM, and from user list.
 670         cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
 671         AbstractTypeMap.erase(Ty);
 672       }
 673     }
 674   }
 675
 676   void remove(ConstantClass *CP) {
 677     sys::SmartScopedLock<true> Lock(ValueMapLock);
 678     typename MapTy::iterator I = FindExistingElement(CP);
 679     assert(I != Map.end() && "Constant not found in constant table!");
 680     assert(I->second == CP && "Didn't find correct element?");
 681
 682     if (HasLargeKey)  // Remember the reverse mapping if needed.
 683       InverseMap.erase(CP);
 684
 685     // Now that we found the entry, make sure this isn't the entry that
 686     // the AbstractTypeMap points to.
 687     const TypeClass *Ty = I->first.first;
 688     if (Ty->isAbstract())
 689       UpdateAbstractTypeMap(static_cast<const DerivedType *>(Ty), I);
 690
 691     Map.erase(I);
 692   }
 693
 694   /// MoveConstantToNewSlot - If we are about to change C to be the element
 695   /// specified by I, update our internal data structures to reflect this
 696   /// fact.
 697   /// NOTE: This function is not locked. It is the responsibility of the
 698   /// caller to enforce proper synchronization if using this method.
 699   void MoveConstantToNewSlot(ConstantClass *C, typename MapTy::iterator I) {
 700     // First, remove the old location of the specified constant in the map.
 701     typename MapTy::iterator OldI = FindExistingElement(C);
 702     assert(OldI != Map.end() && "Constant not found in constant table!");
 703     assert(OldI->second == C && "Didn't find correct element?");
 704
 705     // If this constant is the representative element for its abstract type,
 706     // update the AbstractTypeMap so that the representative element is I.
 707     if (C->getType()->isAbstract()) {
 708       typename AbstractTypeMapTy::iterator ATI =
 709           AbstractTypeMap.find(C->getType());
 710       assert(ATI != AbstractTypeMap.end() &&
 711              "Abstract type not in AbstractTypeMap?");
 712       if (ATI->second == OldI)
 713         ATI->second = I;
 714     }
 715
 716     // Remove the old entry from the map.
 717     Map.erase(OldI);
 718
 719     // Update the inverse map so that we know that this constant is now
 720     // located at descriptor I.
 721     if (HasLargeKey) {
 722       assert(I->second == C && "Bad inversemap entry!");
 723       InverseMap[C] = I;
 724     }
 725   }
 726
 727   void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
 728     sys::SmartScopedLock<true> Lock(ValueMapLock);
 729     typename AbstractTypeMapTy::iterator I = AbstractTypeMap.find(OldTy);
 730
 731     assert(I != AbstractTypeMap.end() &&
 732            "Abstract type not in AbstractTypeMap?");
 733
 734     // Convert a constant at a time until the last one is gone.  The last one
 735     // leaving will remove() itself, causing the AbstractTypeMapEntry to be
 736     // eliminated eventually.
 737     do {
 738       ConstantClass *C = I->second->second;
 739       MapKey Key(cast<TypeClass>(NewTy),
 740                  ConstantKeyData<ConstantClass>::getValType(C));
 741
 742       std::pair<typename MapTy::iterator, bool> IP =
 743         Map.insert(std::make_pair(Key, C));
 744       if (IP.second) {
 745         // The map didn't previously have an appropriate constant in the
 746         // new type.
 747
 748         // Remove the old entry.
 749         typename MapTy::iterator OldI =
 750           Map.find(MapKey(cast<TypeClass>(OldTy), IP.first->first.second));
 751         assert(OldI != Map.end() && "Constant not in map!");
 752         UpdateAbstractTypeMap(OldTy, OldI);
 753         Map.erase(OldI);
 754
 755         // Set the constant's type. This is done in place!
 756         setType(C, NewTy);
 757
 758         // Update the inverse map so that we know that this constant is now
 759         // located at descriptor I.
 760         if (HasLargeKey)
 761           InverseMap[C] = IP.first;
 762
 763         AddAbstractTypeUser(NewTy, IP.first);
 764       } else {
 765         // The map already had an appropriate constant in the new type, so
 766         // there's no longer a need for the old constant.
 767         C->uncheckedReplaceAllUsesWith(IP.first->second);
 768         C->destroyConstant();    // This constant is now dead, destroy it.
 769       }
 770       I = AbstractTypeMap.find(OldTy);
 771     } while (I != AbstractTypeMap.end());
 772   }
 773
 774   // If the type became concrete without being refined to any other existing
 775   // type, we just remove ourselves from the ATU list.
 776   void typeBecameConcrete(const DerivedType *AbsTy) {
 777     AbsTy->removeAbstractTypeUser(this);
 778   }
 779
 780   void dump() const {
 781     DEBUG(errs() << "Constant.cpp: ValueMap\n");
 782   }
 783 };
 784
 785 }
 786
 787 #endif