LLVM  4.0.0
PointerUnion.h
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1 //===- llvm/ADT/PointerUnion.h - Discriminated Union of 2 Ptrs --*- 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 the PointerUnion class, which is a discriminated union of
11 // pointer types.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_ADT_POINTERUNION_H
16 #define LLVM_ADT_POINTERUNION_H
17 
18 #include "llvm/ADT/DenseMapInfo.h"
21 #include <cassert>
22 #include <cstdint>
23 #include <cstddef>
24 
25 namespace llvm {
26 
27 template <typename T> struct PointerUnionTypeSelectorReturn {
28  typedef T Return;
29 };
30 
31 /// Get a type based on whether two types are the same or not.
32 ///
33 /// For:
34 ///
35 /// \code
36 /// typedef typename PointerUnionTypeSelector<T1, T2, EQ, NE>::Return Ret;
37 /// \endcode
38 ///
39 /// Ret will be EQ type if T1 is same as T2 or NE type otherwise.
40 template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
43 };
44 
45 template <typename T, typename RET_EQ, typename RET_NE>
46 struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
48 };
49 
50 template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
52  PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>> {
53  typedef
55 };
56 
57 /// Provide PointerLikeTypeTraits for void* that is used by PointerUnion
58 /// for the two template arguments.
59 template <typename PT1, typename PT2> class PointerUnionUIntTraits {
60 public:
61  static inline void *getAsVoidPointer(void *P) { return P; }
62  static inline void *getFromVoidPointer(void *P) { return P; }
63 
64  enum {
67  NumLowBitsAvailable = PT1BitsAv < PT2BitsAv ? PT1BitsAv : PT2BitsAv
68  };
69 };
70 
71 /// A discriminated union of two pointer types, with the discriminator in the
72 /// low bit of the pointer.
73 ///
74 /// This implementation is extremely efficient in space due to leveraging the
75 /// low bits of the pointer, while exposing a natural and type-safe API.
76 ///
77 /// Common use patterns would be something like this:
78 /// PointerUnion<int*, float*> P;
79 /// P = (int*)0;
80 /// printf("%d %d", P.is<int*>(), P.is<float*>()); // prints "1 0"
81 /// X = P.get<int*>(); // ok.
82 /// Y = P.get<float*>(); // runtime assertion failure.
83 /// Z = P.get<double*>(); // compile time failure.
84 /// P = (float*)0;
85 /// Y = P.get<float*>(); // ok.
86 /// X = P.get<int*>(); // runtime assertion failure.
87 template <typename PT1, typename PT2> class PointerUnion {
88 public:
91 
92 private:
93  ValTy Val;
94 
95  struct IsPT1 {
96  static const int Num = 0;
97  };
98  struct IsPT2 {
99  static const int Num = 1;
100  };
101  template <typename T> struct UNION_DOESNT_CONTAIN_TYPE {};
102 
103 public:
104  PointerUnion() = default;
105 
107  : Val(const_cast<void *>(
108  PointerLikeTypeTraits<PT1>::getAsVoidPointer(V))) {}
110  : Val(const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(V)),
111  1) {}
112 
113  /// Test if the pointer held in the union is null, regardless of
114  /// which type it is.
115  bool isNull() const {
116  // Convert from the void* to one of the pointer types, to make sure that
117  // we recursively strip off low bits if we have a nested PointerUnion.
119  }
120  explicit operator bool() const { return !isNull(); }
121 
122  /// Test if the Union currently holds the type matching T.
123  template <typename T> int is() const {
124  typedef typename ::llvm::PointerUnionTypeSelector<
125  PT1, T, IsPT1, ::llvm::PointerUnionTypeSelector<
126  PT2, T, IsPT2, UNION_DOESNT_CONTAIN_TYPE<T>>>::Return
127  Ty;
128  int TyNo = Ty::Num;
129  return static_cast<int>(Val.getInt()) == TyNo;
130  }
131 
132  /// Returns the value of the specified pointer type.
133  ///
134  /// If the specified pointer type is incorrect, assert.
135  template <typename T> T get() const {
136  assert(is<T>() && "Invalid accessor called");
138  }
139 
140  /// Returns the current pointer if it is of the specified pointer type,
141  /// otherwises returns null.
142  template <typename T> T dyn_cast() const {
143  if (is<T>())
144  return get<T>();
145  return T();
146  }
147 
148  /// If the union is set to the first pointer type get an address pointing to
149  /// it.
150  PT1 const *getAddrOfPtr1() const {
151  return const_cast<PointerUnion *>(this)->getAddrOfPtr1();
152  }
153 
154  /// If the union is set to the first pointer type get an address pointing to
155  /// it.
156  PT1 *getAddrOfPtr1() {
157  assert(is<PT1>() && "Val is not the first pointer");
158  assert(
159  get<PT1>() == Val.getPointer() &&
160  "Can't get the address because PointerLikeTypeTraits changes the ptr");
161  return (PT1 *)Val.getAddrOfPointer();
162  }
163 
164  /// Assignment from nullptr which just clears the union.
165  const PointerUnion &operator=(std::nullptr_t) {
166  Val.initWithPointer(nullptr);
167  return *this;
168  }
169 
170  /// Assignment operators - Allow assigning into this union from either
171  /// pointer type, setting the discriminator to remember what it came from.
172  const PointerUnion &operator=(const PT1 &RHS) {
173  Val.initWithPointer(
174  const_cast<void *>(PointerLikeTypeTraits<PT1>::getAsVoidPointer(RHS)));
175  return *this;
176  }
177  const PointerUnion &operator=(const PT2 &RHS) {
178  Val.setPointerAndInt(
179  const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(RHS)),
180  1);
181  return *this;
182  }
183 
184  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
185  static inline PointerUnion getFromOpaqueValue(void *VP) {
186  PointerUnion V;
187  V.Val = ValTy::getFromOpaqueValue(VP);
188  return V;
189  }
190 };
191 
192 template <typename PT1, typename PT2>
194  return lhs.getOpaqueValue() == rhs.getOpaqueValue();
195 }
196 
197 template <typename PT1, typename PT2>
199  return lhs.getOpaqueValue() != rhs.getOpaqueValue();
200 }
201 
202 template <typename PT1, typename PT2>
203 static bool operator<(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
204  return lhs.getOpaqueValue() < rhs.getOpaqueValue();
205 }
206 
207 // Teach SmallPtrSet that PointerUnion is "basically a pointer", that has
208 // # low bits available = min(PT1bits,PT2bits)-1.
209 template <typename PT1, typename PT2>
211 public:
212  static inline void *getAsVoidPointer(const PointerUnion<PT1, PT2> &P) {
213  return P.getOpaqueValue();
214  }
215 
218  }
219 
220  // The number of bits available are the min of the two pointer types.
221  enum {
222  NumLowBitsAvailable = PointerLikeTypeTraits<
223  typename PointerUnion<PT1, PT2>::ValTy>::NumLowBitsAvailable
224  };
225 };
226 
227 /// A pointer union of three pointer types. See documentation for PointerUnion
228 /// for usage.
229 template <typename PT1, typename PT2, typename PT3> class PointerUnion3 {
230 public:
233 
234 private:
235  ValTy Val;
236 
237  struct IsInnerUnion {
238  ValTy Val;
239  IsInnerUnion(ValTy val) : Val(val) {}
240  template <typename T> int is() const {
241  return Val.template is<InnerUnion>() &&
242  Val.template get<InnerUnion>().template is<T>();
243  }
244  template <typename T> T get() const {
245  return Val.template get<InnerUnion>().template get<T>();
246  }
247  };
248 
249  struct IsPT3 {
250  ValTy Val;
251  IsPT3(ValTy val) : Val(val) {}
252  template <typename T> int is() const { return Val.template is<T>(); }
253  template <typename T> T get() const { return Val.template get<T>(); }
254  };
255 
256 public:
257  PointerUnion3() = default;
258 
259  PointerUnion3(PT1 V) { Val = InnerUnion(V); }
260  PointerUnion3(PT2 V) { Val = InnerUnion(V); }
261  PointerUnion3(PT3 V) { Val = V; }
262 
263  /// Test if the pointer held in the union is null, regardless of
264  /// which type it is.
265  bool isNull() const { return Val.isNull(); }
266  explicit operator bool() const { return !isNull(); }
267 
268  /// Test if the Union currently holds the type matching T.
269  template <typename T> int is() const {
270  // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
271  typedef typename ::llvm::PointerUnionTypeSelector<
272  PT1, T, IsInnerUnion,
274  Ty;
275  return Ty(Val).template is<T>();
276  }
277 
278  /// Returns the value of the specified pointer type.
279  ///
280  /// If the specified pointer type is incorrect, assert.
281  template <typename T> T get() const {
282  assert(is<T>() && "Invalid accessor called");
283  // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
284  typedef typename ::llvm::PointerUnionTypeSelector<
285  PT1, T, IsInnerUnion,
287  Ty;
288  return Ty(Val).template get<T>();
289  }
290 
291  /// Returns the current pointer if it is of the specified pointer type,
292  /// otherwises returns null.
293  template <typename T> T dyn_cast() const {
294  if (is<T>())
295  return get<T>();
296  return T();
297  }
298 
299  /// Assignment from nullptr which just clears the union.
300  const PointerUnion3 &operator=(std::nullptr_t) {
301  Val = nullptr;
302  return *this;
303  }
304 
305  /// Assignment operators - Allow assigning into this union from either
306  /// pointer type, setting the discriminator to remember what it came from.
307  const PointerUnion3 &operator=(const PT1 &RHS) {
308  Val = InnerUnion(RHS);
309  return *this;
310  }
311  const PointerUnion3 &operator=(const PT2 &RHS) {
312  Val = InnerUnion(RHS);
313  return *this;
314  }
315  const PointerUnion3 &operator=(const PT3 &RHS) {
316  Val = RHS;
317  return *this;
318  }
319 
320  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
321  static inline PointerUnion3 getFromOpaqueValue(void *VP) {
322  PointerUnion3 V;
323  V.Val = ValTy::getFromOpaqueValue(VP);
324  return V;
325  }
326 };
327 
328 // Teach SmallPtrSet that PointerUnion3 is "basically a pointer", that has
329 // # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
330 template <typename PT1, typename PT2, typename PT3>
331 class PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3>> {
332 public:
333  static inline void *getAsVoidPointer(const PointerUnion3<PT1, PT2, PT3> &P) {
334  return P.getOpaqueValue();
335  }
336 
339  }
340 
341  // The number of bits available are the min of the two pointer types.
342  enum {
343  NumLowBitsAvailable = PointerLikeTypeTraits<
344  typename PointerUnion3<PT1, PT2, PT3>::ValTy>::NumLowBitsAvailable
345  };
346 };
347 
348 /// A pointer union of four pointer types. See documentation for PointerUnion
349 /// for usage.
350 template <typename PT1, typename PT2, typename PT3, typename PT4>
352 public:
356 
357 private:
358  ValTy Val;
359 
360 public:
361  PointerUnion4() = default;
362 
363  PointerUnion4(PT1 V) { Val = InnerUnion1(V); }
364  PointerUnion4(PT2 V) { Val = InnerUnion1(V); }
365  PointerUnion4(PT3 V) { Val = InnerUnion2(V); }
366  PointerUnion4(PT4 V) { Val = InnerUnion2(V); }
367 
368  /// Test if the pointer held in the union is null, regardless of
369  /// which type it is.
370  bool isNull() const { return Val.isNull(); }
371  explicit operator bool() const { return !isNull(); }
372 
373  /// Test if the Union currently holds the type matching T.
374  template <typename T> int is() const {
375  // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
376  typedef typename ::llvm::PointerUnionTypeSelector<
378  PT2, T, InnerUnion1, InnerUnion2>>::Return Ty;
379  return Val.template is<Ty>() && Val.template get<Ty>().template is<T>();
380  }
381 
382  /// Returns the value of the specified pointer type.
383  ///
384  /// If the specified pointer type is incorrect, assert.
385  template <typename T> T get() const {
386  assert(is<T>() && "Invalid accessor called");
387  // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
388  typedef typename ::llvm::PointerUnionTypeSelector<
390  PT2, T, InnerUnion1, InnerUnion2>>::Return Ty;
391  return Val.template get<Ty>().template get<T>();
392  }
393 
394  /// Returns the current pointer if it is of the specified pointer type,
395  /// otherwises returns null.
396  template <typename T> T dyn_cast() const {
397  if (is<T>())
398  return get<T>();
399  return T();
400  }
401 
402  /// Assignment from nullptr which just clears the union.
403  const PointerUnion4 &operator=(std::nullptr_t) {
404  Val = nullptr;
405  return *this;
406  }
407 
408  /// Assignment operators - Allow assigning into this union from either
409  /// pointer type, setting the discriminator to remember what it came from.
410  const PointerUnion4 &operator=(const PT1 &RHS) {
411  Val = InnerUnion1(RHS);
412  return *this;
413  }
414  const PointerUnion4 &operator=(const PT2 &RHS) {
415  Val = InnerUnion1(RHS);
416  return *this;
417  }
418  const PointerUnion4 &operator=(const PT3 &RHS) {
419  Val = InnerUnion2(RHS);
420  return *this;
421  }
422  const PointerUnion4 &operator=(const PT4 &RHS) {
423  Val = InnerUnion2(RHS);
424  return *this;
425  }
426 
427  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
428  static inline PointerUnion4 getFromOpaqueValue(void *VP) {
429  PointerUnion4 V;
430  V.Val = ValTy::getFromOpaqueValue(VP);
431  return V;
432  }
433 };
434 
435 // Teach SmallPtrSet that PointerUnion4 is "basically a pointer", that has
436 // # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
437 template <typename PT1, typename PT2, typename PT3, typename PT4>
438 class PointerLikeTypeTraits<PointerUnion4<PT1, PT2, PT3, PT4>> {
439 public:
440  static inline void *
442  return P.getOpaqueValue();
443  }
444 
447  }
448 
449  // The number of bits available are the min of the two pointer types.
450  enum {
451  NumLowBitsAvailable = PointerLikeTypeTraits<
452  typename PointerUnion4<PT1, PT2, PT3, PT4>::ValTy>::NumLowBitsAvailable
453  };
454 };
455 
456 // Teach DenseMap how to use PointerUnions as keys.
457 template <typename T, typename U> struct DenseMapInfo<PointerUnion<T, U>> {
461 
462  static inline Pair getEmptyKey() { return Pair(FirstInfo::getEmptyKey()); }
463  static inline Pair getTombstoneKey() {
464  return Pair(FirstInfo::getTombstoneKey());
465  }
466  static unsigned getHashValue(const Pair &PairVal) {
467  intptr_t key = (intptr_t)PairVal.getOpaqueValue();
469  }
470  static bool isEqual(const Pair &LHS, const Pair &RHS) {
471  return LHS.template is<T>() == RHS.template is<T>() &&
472  (LHS.template is<T>() ? FirstInfo::isEqual(LHS.template get<T>(),
473  RHS.template get<T>())
474  : SecondInfo::isEqual(LHS.template get<U>(),
475  RHS.template get<U>()));
476  }
477 };
478 
479 } // end namespace llvm
480 
481 #endif // LLVM_ADT_POINTERUNION_H
const PointerUnion4 & operator=(const PT3 &RHS)
Definition: PointerUnion.h:418
void * getOpaqueValue() const
Definition: PointerUnion.h:320
PointerUnionTypeSelectorReturn< RET_NE >::Return Return
Definition: PointerUnion.h:42
Provide PointerLikeTypeTraits for void* that is used by PointerUnion for the two template arguments...
Definition: PointerUnion.h:59
const PointerUnion4 & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:410
const PointerUnion & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:172
PT1 * getAddrOfPtr1()
If the union is set to the first pointer type get an address pointing to it.
Definition: PointerUnion.h:156
static PointerUnion4 getFromOpaqueValue(void *VP)
Definition: PointerUnion.h:428
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null...
Definition: PointerUnion.h:142
const PointerUnion & operator=(const PT2 &RHS)
Definition: PointerUnion.h:177
PointerUnion< InnerUnion, PT3 > ValTy
Definition: PointerUnion.h:232
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:374
static unsigned getHashValue(const Pair &PairVal)
Definition: PointerUnion.h:466
PointerUnion< InnerUnion1, InnerUnion2 > ValTy
Definition: PointerUnion.h:355
PointerUnion()=default
A traits type that is used to handle pointer types and things that are just wrappers for pointers as ...
static PointerUnion< PT1, PT2 > getFromVoidPointer(void *P)
Definition: PointerUnion.h:216
static PointerUnion getFromOpaqueValue(void *VP)
Definition: PointerUnion.h:185
PointerTy const * getAddrOfPointer() const
void * getOpaqueValue() const
Definition: PointerUnion.h:184
PointerUnionTypeSelector< T1, T2, RET_EQ, RET_NE >::Return Return
Definition: PointerUnion.h:54
static void * getAsVoidPointer(void *P)
Definition: PointerUnion.h:61
static void * getAsVoidPointer(const PointerUnion3< PT1, PT2, PT3 > &P)
Definition: PointerUnion.h:333
Get a type based on whether two types are the same or not.
Definition: PointerUnion.h:41
const PointerUnion3 & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:300
static PointerUnion4< PT1, PT2, PT3, PT4 > getFromVoidPointer(void *P)
Definition: PointerUnion.h:445
PointerTy getPointer() const
static bool isEqual(const Function &Caller, const Function &Callee)
#define T
const PointerUnion3 & operator=(const PT3 &RHS)
Definition: PointerUnion.h:315
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null...
Definition: PointerUnion.h:293
static void * getAsVoidPointer(const PointerUnion< PT1, PT2 > &P)
Definition: PointerUnion.h:212
IntType getInt() const
const PointerUnion4 & operator=(const PT2 &RHS)
Definition: PointerUnion.h:414
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:265
#define P(N)
const PointerUnion & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:165
PointerIntPair - This class implements a pair of a pointer and small integer.
PointerUnion3()=default
void initWithPointer(PointerTy PtrVal)
const PointerUnion3 & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:307
PT1 const * getAddrOfPtr1() const
If the union is set to the first pointer type get an address pointing to it.
Definition: PointerUnion.h:150
const PointerUnion4 & operator=(const PT4 &RHS)
Definition: PointerUnion.h:422
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:269
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:370
static PointerUnion3< PT1, PT2, PT3 > getFromVoidPointer(void *P)
Definition: PointerUnion.h:337
PointerUnionTypeSelectorReturn< RET_EQ >::Return Return
Definition: PointerUnion.h:47
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:115
static PointerUnion3 getFromOpaqueValue(void *VP)
Definition: PointerUnion.h:321
static void * getAsVoidPointer(const PointerUnion4< PT1, PT2, PT3, PT4 > &P)
Definition: PointerUnion.h:441
const PointerUnion4 & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:403
void * getOpaqueValue() const
PointerUnion< PT1, PT2 > InnerUnion
Definition: PointerUnion.h:231
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null...
Definition: PointerUnion.h:396
PointerUnion4()=default
void setPointerAndInt(PointerTy PtrVal, IntType IntVal)
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:1724
void * getOpaqueValue() const
Definition: PointerUnion.h:427
A pointer union of three pointer types.
Definition: PointerUnion.h:229
const PointerUnion3 & operator=(const PT2 &RHS)
Definition: PointerUnion.h:311
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static bool isEqual(const Pair &LHS, const Pair &RHS)
Definition: PointerUnion.h:470
PointerUnion< PT1, PT2 > InnerUnion1
Definition: PointerUnion.h:353
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1722
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:123
PointerIntPair< void *, 1, bool, PointerUnionUIntTraits< PT1, PT2 > > ValTy
Definition: PointerUnion.h:90
static void * getFromVoidPointer(void *P)
Definition: PointerUnion.h:62
PointerUnion< PT3, PT4 > InnerUnion2
Definition: PointerUnion.h:354
#define T1
A pointer union of four pointer types.
Definition: PointerUnion.h:351
A discriminated union of two pointer types, with the discriminator in the low bit of the pointer...
Definition: PointerUnion.h:87