1193323Sed//===- llvm/ADT/PointerUnion.h - Discriminated Union of 2 Ptrs --*- C++ -*-===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This file defines the PointerUnion class, which is a discriminated union of 11193323Sed// pointer types. 12193323Sed// 13193323Sed//===----------------------------------------------------------------------===// 14193323Sed 15193323Sed#ifndef LLVM_ADT_POINTERUNION_H 16193323Sed#define LLVM_ADT_POINTERUNION_H 17193323Sed 18263508Sdim#include "llvm/Support/Compiler.h" 19193323Sed#include "llvm/ADT/PointerIntPair.h" 20193323Sed 21193323Sednamespace llvm { 22193323Sed 23221345Sdim template <typename T> 24221345Sdim struct PointerUnionTypeSelectorReturn { 25221345Sdim typedef T Return; 26221345Sdim }; 27221345Sdim 28221345Sdim /// \brief Get a type based on whether two types are the same or not. For: 29221345Sdim /// @code 30221345Sdim /// typedef typename PointerUnionTypeSelector<T1, T2, EQ, NE>::Return Ret; 31221345Sdim /// @endcode 32221345Sdim /// Ret will be EQ type if T1 is same as T2 or NE type otherwise. 33221345Sdim template <typename T1, typename T2, typename RET_EQ, typename RET_NE> 34221345Sdim struct PointerUnionTypeSelector { 35221345Sdim typedef typename PointerUnionTypeSelectorReturn<RET_NE>::Return Return; 36221345Sdim }; 37221345Sdim 38221345Sdim template <typename T, typename RET_EQ, typename RET_NE> 39221345Sdim struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> { 40221345Sdim typedef typename PointerUnionTypeSelectorReturn<RET_EQ>::Return Return; 41221345Sdim }; 42221345Sdim 43221345Sdim template <typename T1, typename T2, typename RET_EQ, typename RET_NE> 44221345Sdim struct PointerUnionTypeSelectorReturn< 45221345Sdim PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE> > { 46221345Sdim typedef typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return 47221345Sdim Return; 48221345Sdim }; 49221345Sdim 50193323Sed /// Provide PointerLikeTypeTraits for void* that is used by PointerUnion 51193323Sed /// for the two template arguments. 52193323Sed template <typename PT1, typename PT2> 53193323Sed class PointerUnionUIntTraits { 54193323Sed public: 55193323Sed static inline void *getAsVoidPointer(void *P) { return P; } 56193323Sed static inline void *getFromVoidPointer(void *P) { return P; } 57193323Sed enum { 58239462Sdim PT1BitsAv = (int)(PointerLikeTypeTraits<PT1>::NumLowBitsAvailable), 59239462Sdim PT2BitsAv = (int)(PointerLikeTypeTraits<PT2>::NumLowBitsAvailable), 60193323Sed NumLowBitsAvailable = PT1BitsAv < PT2BitsAv ? PT1BitsAv : PT2BitsAv 61193323Sed }; 62193323Sed }; 63193323Sed 64193323Sed /// PointerUnion - This implements a discriminated union of two pointer types, 65193323Sed /// and keeps the discriminator bit-mangled into the low bits of the pointer. 66193323Sed /// This allows the implementation to be extremely efficient in space, but 67193323Sed /// permits a very natural and type-safe API. 68193323Sed /// 69193323Sed /// Common use patterns would be something like this: 70193323Sed /// PointerUnion<int*, float*> P; 71193323Sed /// P = (int*)0; 72193323Sed /// printf("%d %d", P.is<int*>(), P.is<float*>()); // prints "1 0" 73193323Sed /// X = P.get<int*>(); // ok. 74193323Sed /// Y = P.get<float*>(); // runtime assertion failure. 75263508Sdim /// Z = P.get<double*>(); // compile time failure. 76193323Sed /// P = (float*)0; 77193323Sed /// Y = P.get<float*>(); // ok. 78193323Sed /// X = P.get<int*>(); // runtime assertion failure. 79193323Sed template <typename PT1, typename PT2> 80193323Sed class PointerUnion { 81193323Sed public: 82193323Sed typedef PointerIntPair<void*, 1, bool, 83193323Sed PointerUnionUIntTraits<PT1,PT2> > ValTy; 84193323Sed private: 85193323Sed ValTy Val; 86221345Sdim 87221345Sdim struct IsPT1 { 88221345Sdim static const int Num = 0; 89221345Sdim }; 90221345Sdim struct IsPT2 { 91221345Sdim static const int Num = 1; 92221345Sdim }; 93221345Sdim template <typename T> 94221345Sdim struct UNION_DOESNT_CONTAIN_TYPE { }; 95221345Sdim 96193323Sed public: 97193323Sed PointerUnion() {} 98193323Sed 99249423Sdim PointerUnion(PT1 V) : Val( 100249423Sdim const_cast<void *>(PointerLikeTypeTraits<PT1>::getAsVoidPointer(V))) { 101193323Sed } 102249423Sdim PointerUnion(PT2 V) : Val( 103249423Sdim const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(V)), 1) { 104193323Sed } 105193323Sed 106198090Srdivacky /// isNull - Return true if the pointer held in the union is null, 107193323Sed /// regardless of which type it is. 108226633Sdim bool isNull() const { 109226633Sdim // Convert from the void* to one of the pointer types, to make sure that 110226633Sdim // we recursively strip off low bits if we have a nested PointerUnion. 111226633Sdim return !PointerLikeTypeTraits<PT1>::getFromVoidPointer(Val.getPointer()); 112226633Sdim } 113263508Sdim LLVM_EXPLICIT operator bool() const { return !isNull(); } 114193323Sed 115193323Sed /// is<T>() return true if the Union currently holds the type matching T. 116193323Sed template<typename T> 117193323Sed int is() const { 118221345Sdim typedef typename 119221345Sdim ::llvm::PointerUnionTypeSelector<PT1, T, IsPT1, 120221345Sdim ::llvm::PointerUnionTypeSelector<PT2, T, IsPT2, 121221345Sdim UNION_DOESNT_CONTAIN_TYPE<T> > >::Return Ty; 122221345Sdim int TyNo = Ty::Num; 123195340Sed return static_cast<int>(Val.getInt()) == TyNo; 124193323Sed } 125193323Sed 126193323Sed /// get<T>() - Return the value of the specified pointer type. If the 127193323Sed /// specified pointer type is incorrect, assert. 128193323Sed template<typename T> 129193323Sed T get() const { 130193323Sed assert(is<T>() && "Invalid accessor called"); 131193323Sed return PointerLikeTypeTraits<T>::getFromVoidPointer(Val.getPointer()); 132193323Sed } 133193323Sed 134193323Sed /// dyn_cast<T>() - If the current value is of the specified pointer type, 135193323Sed /// return it, otherwise return null. 136193323Sed template<typename T> 137193323Sed T dyn_cast() const { 138193323Sed if (is<T>()) return get<T>(); 139193323Sed return T(); 140193323Sed } 141218893Sdim 142234353Sdim /// \brief If the union is set to the first pointer type get an address 143234353Sdim /// pointing to it. 144234353Sdim PT1 const *getAddrOfPtr1() const { 145234353Sdim return const_cast<PointerUnion *>(this)->getAddrOfPtr1(); 146234353Sdim } 147234353Sdim 148234353Sdim /// \brief If the union is set to the first pointer type get an address 149234353Sdim /// pointing to it. 150234353Sdim PT1 *getAddrOfPtr1() { 151218893Sdim assert(is<PT1>() && "Val is not the first pointer"); 152218893Sdim assert(get<PT1>() == Val.getPointer() && 153218893Sdim "Can't get the address because PointerLikeTypeTraits changes the ptr"); 154234353Sdim return (PT1 *)Val.getAddrOfPointer(); 155218893Sdim } 156193323Sed 157193323Sed /// Assignment operators - Allow assigning into this union from either 158193323Sed /// pointer type, setting the discriminator to remember what it came from. 159193323Sed const PointerUnion &operator=(const PT1 &RHS) { 160249423Sdim Val.initWithPointer( 161193323Sed const_cast<void *>(PointerLikeTypeTraits<PT1>::getAsVoidPointer(RHS))); 162193323Sed return *this; 163193323Sed } 164193323Sed const PointerUnion &operator=(const PT2 &RHS) { 165249423Sdim Val.setPointerAndInt( 166249423Sdim const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(RHS)), 167249423Sdim 1); 168193323Sed return *this; 169193323Sed } 170193323Sed 171193323Sed void *getOpaqueValue() const { return Val.getOpaqueValue(); } 172206083Srdivacky static inline PointerUnion getFromOpaqueValue(void *VP) { 173193323Sed PointerUnion V; 174193323Sed V.Val = ValTy::getFromOpaqueValue(VP); 175193323Sed return V; 176193323Sed } 177193323Sed }; 178263508Sdim 179263508Sdim template<typename PT1, typename PT2> 180263508Sdim static bool operator==(PointerUnion<PT1, PT2> lhs, 181263508Sdim PointerUnion<PT1, PT2> rhs) { 182263508Sdim return lhs.getOpaqueValue() == rhs.getOpaqueValue(); 183263508Sdim } 184263508Sdim 185263508Sdim template<typename PT1, typename PT2> 186263508Sdim static bool operator!=(PointerUnion<PT1, PT2> lhs, 187263508Sdim PointerUnion<PT1, PT2> rhs) { 188263508Sdim return lhs.getOpaqueValue() != rhs.getOpaqueValue(); 189263508Sdim } 190263508Sdim 191193323Sed // Teach SmallPtrSet that PointerUnion is "basically a pointer", that has 192193323Sed // # low bits available = min(PT1bits,PT2bits)-1. 193193323Sed template<typename PT1, typename PT2> 194193323Sed class PointerLikeTypeTraits<PointerUnion<PT1, PT2> > { 195193323Sed public: 196193323Sed static inline void * 197193323Sed getAsVoidPointer(const PointerUnion<PT1, PT2> &P) { 198193323Sed return P.getOpaqueValue(); 199193323Sed } 200193323Sed static inline PointerUnion<PT1, PT2> 201193323Sed getFromVoidPointer(void *P) { 202193323Sed return PointerUnion<PT1, PT2>::getFromOpaqueValue(P); 203193323Sed } 204193323Sed 205193323Sed // The number of bits available are the min of the two pointer types. 206193323Sed enum { 207193323Sed NumLowBitsAvailable = 208193323Sed PointerLikeTypeTraits<typename PointerUnion<PT1,PT2>::ValTy> 209193323Sed ::NumLowBitsAvailable 210193323Sed }; 211193323Sed }; 212193323Sed 213193323Sed 214193323Sed /// PointerUnion3 - This is a pointer union of three pointer types. See 215193323Sed /// documentation for PointerUnion for usage. 216193323Sed template <typename PT1, typename PT2, typename PT3> 217193323Sed class PointerUnion3 { 218193323Sed public: 219193323Sed typedef PointerUnion<PT1, PT2> InnerUnion; 220193323Sed typedef PointerUnion<InnerUnion, PT3> ValTy; 221193323Sed private: 222193323Sed ValTy Val; 223221345Sdim 224221345Sdim struct IsInnerUnion { 225221345Sdim ValTy Val; 226221345Sdim IsInnerUnion(ValTy val) : Val(val) { } 227221345Sdim template<typename T> 228221345Sdim int is() const { 229221345Sdim return Val.template is<InnerUnion>() && 230221345Sdim Val.template get<InnerUnion>().template is<T>(); 231221345Sdim } 232221345Sdim template<typename T> 233221345Sdim T get() const { 234221345Sdim return Val.template get<InnerUnion>().template get<T>(); 235221345Sdim } 236221345Sdim }; 237221345Sdim 238221345Sdim struct IsPT3 { 239221345Sdim ValTy Val; 240221345Sdim IsPT3(ValTy val) : Val(val) { } 241221345Sdim template<typename T> 242221345Sdim int is() const { 243221345Sdim return Val.template is<T>(); 244221345Sdim } 245221345Sdim template<typename T> 246221345Sdim T get() const { 247221345Sdim return Val.template get<T>(); 248221345Sdim } 249221345Sdim }; 250221345Sdim 251193323Sed public: 252193323Sed PointerUnion3() {} 253193323Sed 254193323Sed PointerUnion3(PT1 V) { 255193323Sed Val = InnerUnion(V); 256193323Sed } 257193323Sed PointerUnion3(PT2 V) { 258193323Sed Val = InnerUnion(V); 259193323Sed } 260193323Sed PointerUnion3(PT3 V) { 261193323Sed Val = V; 262193323Sed } 263193323Sed 264198090Srdivacky /// isNull - Return true if the pointer held in the union is null, 265193323Sed /// regardless of which type it is. 266193323Sed bool isNull() const { return Val.isNull(); } 267263508Sdim LLVM_EXPLICIT operator bool() const { return !isNull(); } 268193323Sed 269193323Sed /// is<T>() return true if the Union currently holds the type matching T. 270193323Sed template<typename T> 271193323Sed int is() const { 272221345Sdim // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3. 273221345Sdim typedef typename 274221345Sdim ::llvm::PointerUnionTypeSelector<PT1, T, IsInnerUnion, 275221345Sdim ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3 > 276221345Sdim >::Return Ty; 277234353Sdim return Ty(Val).template is<T>(); 278193323Sed } 279193323Sed 280193323Sed /// get<T>() - Return the value of the specified pointer type. If the 281193323Sed /// specified pointer type is incorrect, assert. 282193323Sed template<typename T> 283193323Sed T get() const { 284193323Sed assert(is<T>() && "Invalid accessor called"); 285221345Sdim // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3. 286221345Sdim typedef typename 287221345Sdim ::llvm::PointerUnionTypeSelector<PT1, T, IsInnerUnion, 288221345Sdim ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3 > 289221345Sdim >::Return Ty; 290234353Sdim return Ty(Val).template get<T>(); 291193323Sed } 292193323Sed 293193323Sed /// dyn_cast<T>() - If the current value is of the specified pointer type, 294193323Sed /// return it, otherwise return null. 295193323Sed template<typename T> 296193323Sed T dyn_cast() const { 297193323Sed if (is<T>()) return get<T>(); 298193323Sed return T(); 299193323Sed } 300193323Sed 301193323Sed /// Assignment operators - Allow assigning into this union from either 302193323Sed /// pointer type, setting the discriminator to remember what it came from. 303193323Sed const PointerUnion3 &operator=(const PT1 &RHS) { 304193323Sed Val = InnerUnion(RHS); 305193323Sed return *this; 306193323Sed } 307193323Sed const PointerUnion3 &operator=(const PT2 &RHS) { 308193323Sed Val = InnerUnion(RHS); 309193323Sed return *this; 310193323Sed } 311193323Sed const PointerUnion3 &operator=(const PT3 &RHS) { 312193323Sed Val = RHS; 313193323Sed return *this; 314193323Sed } 315193323Sed 316193323Sed void *getOpaqueValue() const { return Val.getOpaqueValue(); } 317206083Srdivacky static inline PointerUnion3 getFromOpaqueValue(void *VP) { 318193323Sed PointerUnion3 V; 319193323Sed V.Val = ValTy::getFromOpaqueValue(VP); 320193323Sed return V; 321193323Sed } 322193323Sed }; 323193323Sed 324193323Sed // Teach SmallPtrSet that PointerUnion3 is "basically a pointer", that has 325193323Sed // # low bits available = min(PT1bits,PT2bits,PT2bits)-2. 326193323Sed template<typename PT1, typename PT2, typename PT3> 327193323Sed class PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3> > { 328193323Sed public: 329193323Sed static inline void * 330193323Sed getAsVoidPointer(const PointerUnion3<PT1, PT2, PT3> &P) { 331193323Sed return P.getOpaqueValue(); 332193323Sed } 333193323Sed static inline PointerUnion3<PT1, PT2, PT3> 334193323Sed getFromVoidPointer(void *P) { 335193323Sed return PointerUnion3<PT1, PT2, PT3>::getFromOpaqueValue(P); 336193323Sed } 337193323Sed 338193323Sed // The number of bits available are the min of the two pointer types. 339193323Sed enum { 340193323Sed NumLowBitsAvailable = 341193323Sed PointerLikeTypeTraits<typename PointerUnion3<PT1, PT2, PT3>::ValTy> 342193323Sed ::NumLowBitsAvailable 343193323Sed }; 344193323Sed }; 345198090Srdivacky 346198090Srdivacky /// PointerUnion4 - This is a pointer union of four pointer types. See 347198090Srdivacky /// documentation for PointerUnion for usage. 348198090Srdivacky template <typename PT1, typename PT2, typename PT3, typename PT4> 349198090Srdivacky class PointerUnion4 { 350198090Srdivacky public: 351198090Srdivacky typedef PointerUnion<PT1, PT2> InnerUnion1; 352198090Srdivacky typedef PointerUnion<PT3, PT4> InnerUnion2; 353198090Srdivacky typedef PointerUnion<InnerUnion1, InnerUnion2> ValTy; 354198090Srdivacky private: 355198090Srdivacky ValTy Val; 356198090Srdivacky public: 357198090Srdivacky PointerUnion4() {} 358198090Srdivacky 359198090Srdivacky PointerUnion4(PT1 V) { 360198090Srdivacky Val = InnerUnion1(V); 361198090Srdivacky } 362198090Srdivacky PointerUnion4(PT2 V) { 363198090Srdivacky Val = InnerUnion1(V); 364198090Srdivacky } 365198090Srdivacky PointerUnion4(PT3 V) { 366198090Srdivacky Val = InnerUnion2(V); 367198090Srdivacky } 368198090Srdivacky PointerUnion4(PT4 V) { 369198090Srdivacky Val = InnerUnion2(V); 370198090Srdivacky } 371198090Srdivacky 372198090Srdivacky /// isNull - Return true if the pointer held in the union is null, 373198090Srdivacky /// regardless of which type it is. 374198090Srdivacky bool isNull() const { return Val.isNull(); } 375263508Sdim LLVM_EXPLICIT operator bool() const { return !isNull(); } 376198090Srdivacky 377198090Srdivacky /// is<T>() return true if the Union currently holds the type matching T. 378198090Srdivacky template<typename T> 379198090Srdivacky int is() const { 380221345Sdim // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2. 381221345Sdim typedef typename 382221345Sdim ::llvm::PointerUnionTypeSelector<PT1, T, InnerUnion1, 383221345Sdim ::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1, InnerUnion2 > 384221345Sdim >::Return Ty; 385221345Sdim return Val.template is<Ty>() && 386221345Sdim Val.template get<Ty>().template is<T>(); 387198090Srdivacky } 388198090Srdivacky 389198090Srdivacky /// get<T>() - Return the value of the specified pointer type. If the 390198090Srdivacky /// specified pointer type is incorrect, assert. 391198090Srdivacky template<typename T> 392198090Srdivacky T get() const { 393198090Srdivacky assert(is<T>() && "Invalid accessor called"); 394221345Sdim // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2. 395221345Sdim typedef typename 396221345Sdim ::llvm::PointerUnionTypeSelector<PT1, T, InnerUnion1, 397221345Sdim ::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1, InnerUnion2 > 398221345Sdim >::Return Ty; 399221345Sdim return Val.template get<Ty>().template get<T>(); 400198090Srdivacky } 401198090Srdivacky 402198090Srdivacky /// dyn_cast<T>() - If the current value is of the specified pointer type, 403198090Srdivacky /// return it, otherwise return null. 404198090Srdivacky template<typename T> 405198090Srdivacky T dyn_cast() const { 406198090Srdivacky if (is<T>()) return get<T>(); 407198090Srdivacky return T(); 408198090Srdivacky } 409198090Srdivacky 410198090Srdivacky /// Assignment operators - Allow assigning into this union from either 411198090Srdivacky /// pointer type, setting the discriminator to remember what it came from. 412198090Srdivacky const PointerUnion4 &operator=(const PT1 &RHS) { 413198090Srdivacky Val = InnerUnion1(RHS); 414198090Srdivacky return *this; 415198090Srdivacky } 416198090Srdivacky const PointerUnion4 &operator=(const PT2 &RHS) { 417198090Srdivacky Val = InnerUnion1(RHS); 418198090Srdivacky return *this; 419198090Srdivacky } 420198090Srdivacky const PointerUnion4 &operator=(const PT3 &RHS) { 421198090Srdivacky Val = InnerUnion2(RHS); 422198090Srdivacky return *this; 423198090Srdivacky } 424198090Srdivacky const PointerUnion4 &operator=(const PT4 &RHS) { 425198090Srdivacky Val = InnerUnion2(RHS); 426198090Srdivacky return *this; 427198090Srdivacky } 428198090Srdivacky 429198090Srdivacky void *getOpaqueValue() const { return Val.getOpaqueValue(); } 430206083Srdivacky static inline PointerUnion4 getFromOpaqueValue(void *VP) { 431198090Srdivacky PointerUnion4 V; 432198090Srdivacky V.Val = ValTy::getFromOpaqueValue(VP); 433198090Srdivacky return V; 434198090Srdivacky } 435198090Srdivacky }; 436198090Srdivacky 437198090Srdivacky // Teach SmallPtrSet that PointerUnion4 is "basically a pointer", that has 438198090Srdivacky // # low bits available = min(PT1bits,PT2bits,PT2bits)-2. 439198090Srdivacky template<typename PT1, typename PT2, typename PT3, typename PT4> 440198090Srdivacky class PointerLikeTypeTraits<PointerUnion4<PT1, PT2, PT3, PT4> > { 441198090Srdivacky public: 442198090Srdivacky static inline void * 443198090Srdivacky getAsVoidPointer(const PointerUnion4<PT1, PT2, PT3, PT4> &P) { 444198090Srdivacky return P.getOpaqueValue(); 445198090Srdivacky } 446198090Srdivacky static inline PointerUnion4<PT1, PT2, PT3, PT4> 447198090Srdivacky getFromVoidPointer(void *P) { 448198090Srdivacky return PointerUnion4<PT1, PT2, PT3, PT4>::getFromOpaqueValue(P); 449198090Srdivacky } 450198090Srdivacky 451198090Srdivacky // The number of bits available are the min of the two pointer types. 452198090Srdivacky enum { 453198090Srdivacky NumLowBitsAvailable = 454198090Srdivacky PointerLikeTypeTraits<typename PointerUnion4<PT1, PT2, PT3, PT4>::ValTy> 455198090Srdivacky ::NumLowBitsAvailable 456198090Srdivacky }; 457198090Srdivacky }; 458193323Sed} 459193323Sed 460193323Sed#endif 461