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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"
19#include "llvm/ADT/PointerIntPair.h"
20#include "llvm/Support/PointerLikeTypeTraits.h"
21#include <cassert>
22#include <cstddef>
23#include <cstdint>
24
25namespace llvm {
26
27template <typename T> struct PointerUnionTypeSelectorReturn {
28 using Return = T;
29};
30
31/// Get a type based on whether two types are the same or not.
32///
33/// For:
34///
35/// \code
36/// using Ret = typename PointerUnionTypeSelector<T1, T2, EQ, NE>::Return;
37/// \endcode
38///
39/// Ret will be EQ type if T1 is same as T2 or NE type otherwise.
40template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
41struct PointerUnionTypeSelector {
42 using Return = typename PointerUnionTypeSelectorReturn<RET_NE>::Return;
43};
44
45template <typename T, typename RET_EQ, typename RET_NE>
46struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
47 using Return = typename PointerUnionTypeSelectorReturn<RET_EQ>::Return;
48};
49
50template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
51struct PointerUnionTypeSelectorReturn<
52 PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>> {
53 using Return =
54 typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return;
55};
56
57/// Provide PointerLikeTypeTraits for void* that is used by PointerUnion
58/// for the two template arguments.
59template <typename PT1, typename PT2> class PointerUnionUIntTraits {
60public:
61 static inline void *getAsVoidPointer(void *P) { return P; }
62 static inline void *getFromVoidPointer(void *P) { return P; }
63
64 enum {
65 PT1BitsAv = (int)(PointerLikeTypeTraits<PT1>::NumLowBitsAvailable),
66 PT2BitsAv = (int)(PointerLikeTypeTraits<PT2>::NumLowBitsAvailable),
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.
87template <typename PT1, typename PT2> class PointerUnion {
88public:
89 using ValTy =
90 PointerIntPair<void *, 1, bool, PointerUnionUIntTraits<PT1, PT2>>;
91
92private:
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
103public:
104 PointerUnion() = default;
105 PointerUnion(PT1 V)
106 : Val(const_cast<void *>(
107 PointerLikeTypeTraits<PT1>::getAsVoidPointer(V))) {}
108 PointerUnion(PT2 V)
109 : Val(const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(V)),
110 1) {}
111
112 /// Test if the pointer held in the union is null, regardless of
113 /// which type it is.
114 bool isNull() const {
115 // Convert from the void* to one of the pointer types, to make sure that
116 // we recursively strip off low bits if we have a nested PointerUnion.
117 return !PointerLikeTypeTraits<PT1>::getFromVoidPointer(Val.getPointer());
118 }
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 using Ty = typename ::llvm::PointerUnionTypeSelector<
125 PT1, T, IsPT1,
126 ::llvm::PointerUnionTypeSelector<PT2, T, IsPT2,
127 UNION_DOESNT_CONTAIN_TYPE<T>>>::Return;
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");
137 return PointerLikeTypeTraits<T>::getFromVoidPointer(Val.getPointer());
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 const_cast<PT1 *>(
162 reinterpret_cast<const PT1 *>(Val.getAddrOfPointer()));
163 }
164
165 /// Assignment from nullptr which just clears the union.
166 const PointerUnion &operator=(std::nullptr_t) {
167 Val.initWithPointer(nullptr);
168 return *this;
169 }
170
171 /// Assignment operators - Allow assigning into this union from either
172 /// pointer type, setting the discriminator to remember what it came from.
173 const PointerUnion &operator=(const PT1 &RHS) {
174 Val.initWithPointer(
175 const_cast<void *>(PointerLikeTypeTraits<PT1>::getAsVoidPointer(RHS)));
176 return *this;
177 }
178 const PointerUnion &operator=(const PT2 &RHS) {
179 Val.setPointerAndInt(
180 const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(RHS)),
181 1);
182 return *this;
183 }
184
185 void *getOpaqueValue() const { return Val.getOpaqueValue(); }
186 static inline PointerUnion getFromOpaqueValue(void *VP) {
187 PointerUnion V;
188 V.Val = ValTy::getFromOpaqueValue(VP);
189 return V;
190 }
191};
192
193template <typename PT1, typename PT2>
194bool operator==(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
195 return lhs.getOpaqueValue() == rhs.getOpaqueValue();
196}
197
198template <typename PT1, typename PT2>
199bool operator!=(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
200 return lhs.getOpaqueValue() != rhs.getOpaqueValue();
201}
202
203template <typename PT1, typename PT2>
204bool operator<(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
205 return lhs.getOpaqueValue() < rhs.getOpaqueValue();
206}
207
208// Teach SmallPtrSet that PointerUnion is "basically a pointer", that has
209// # low bits available = min(PT1bits,PT2bits)-1.
210template <typename PT1, typename PT2>
211struct PointerLikeTypeTraits<PointerUnion<PT1, PT2>> {
212 static inline void *getAsVoidPointer(const PointerUnion<PT1, PT2> &P) {
213 return P.getOpaqueValue();
214 }
215
216 static inline PointerUnion<PT1, PT2> getFromVoidPointer(void *P) {
217 return PointerUnion<PT1, PT2>::getFromOpaqueValue(P);
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.
229template <typename PT1, typename PT2, typename PT3> class PointerUnion3 {
230public:
231 using InnerUnion = PointerUnion<PT1, PT2>;
232 using ValTy = PointerUnion<InnerUnion, PT3>;
233
234private:
235 ValTy Val;
236
237 struct IsInnerUnion {
238 ValTy Val;
239
240 IsInnerUnion(ValTy val) : Val(val) {}
241
242 template <typename T> int is() const {
243 return Val.template is<InnerUnion>() &&
244 Val.template get<InnerUnion>().template is<T>();
245 }
246
247 template <typename T> T get() const {
248 return Val.template get<InnerUnion>().template get<T>();
249 }
250 };
251
252 struct IsPT3 {
253 ValTy Val;
254
255 IsPT3(ValTy val) : Val(val) {}
256
257 template <typename T> int is() const { return Val.template is<T>(); }
258 template <typename T> T get() const { return Val.template get<T>(); }
259 };
260
261public:
262 PointerUnion3() = default;
263 PointerUnion3(PT1 V) { Val = InnerUnion(V); }
264 PointerUnion3(PT2 V) { Val = InnerUnion(V); }
265 PointerUnion3(PT3 V) { Val = V; }
266
267 /// Test if the pointer held in the union is null, regardless of
268 /// which type it is.
269 bool isNull() const { return Val.isNull(); }
270 explicit operator bool() const { return !isNull(); }
271
272 /// Test if the Union currently holds the type matching T.
273 template <typename T> int is() const {
274 // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
275 using Ty = typename ::llvm::PointerUnionTypeSelector<
276 PT1, T, IsInnerUnion,
277 ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3>>::Return;
278 return Ty(Val).template is<T>();
279 }
280
281 /// Returns the value of the specified pointer type.
282 ///
283 /// If the specified pointer type is incorrect, assert.
284 template <typename T> T get() const {
285 assert(is<T>() && "Invalid accessor called");
286 // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
287 using Ty = typename ::llvm::PointerUnionTypeSelector<
288 PT1, T, IsInnerUnion,
289 ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3>>::Return;
290 return Ty(Val).template get<T>();
291 }
292
293 /// Returns the current pointer if it is of the specified pointer type,
294 /// otherwises returns null.
295 template <typename T> T dyn_cast() const {
296 if (is<T>())
297 return get<T>();
298 return T();
299 }
300
301 /// Assignment from nullptr which just clears the union.
302 const PointerUnion3 &operator=(std::nullptr_t) {
303 Val = nullptr;
304 return *this;
305 }
306
307 /// Assignment operators - Allow assigning into this union from either
308 /// pointer type, setting the discriminator to remember what it came from.
309 const PointerUnion3 &operator=(const PT1 &RHS) {
310 Val = InnerUnion(RHS);
311 return *this;
312 }
313 const PointerUnion3 &operator=(const PT2 &RHS) {
314 Val = InnerUnion(RHS);
315 return *this;
316 }
317 const PointerUnion3 &operator=(const PT3 &RHS) {
318 Val = RHS;
319 return *this;
320 }
321
322 void *getOpaqueValue() const { return Val.getOpaqueValue(); }
323 static inline PointerUnion3 getFromOpaqueValue(void *VP) {
324 PointerUnion3 V;
325 V.Val = ValTy::getFromOpaqueValue(VP);
326 return V;
327 }
328};
329
330// Teach SmallPtrSet that PointerUnion3 is "basically a pointer", that has
331// # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
332template <typename PT1, typename PT2, typename PT3>
333struct PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3>> {
334 static inline void *getAsVoidPointer(const PointerUnion3<PT1, PT2, PT3> &P) {
335 return P.getOpaqueValue();
336 }
337
338 static inline PointerUnion3<PT1, PT2, PT3> getFromVoidPointer(void *P) {
339 return PointerUnion3<PT1, PT2, PT3>::getFromOpaqueValue(P);
340 }
341
342 // The number of bits available are the min of the two pointer types.
343 enum {
344 NumLowBitsAvailable = PointerLikeTypeTraits<
345 typename PointerUnion3<PT1, PT2, PT3>::ValTy>::NumLowBitsAvailable
346 };
347};
348
349template <typename PT1, typename PT2, typename PT3>
350bool operator<(PointerUnion3<PT1, PT2, PT3> lhs,
351 PointerUnion3<PT1, PT2, PT3> rhs) {
352 return lhs.getOpaqueValue() < rhs.getOpaqueValue();
353}
354
355/// A pointer union of four pointer types. See documentation for PointerUnion
356/// for usage.
357template <typename PT1, typename PT2, typename PT3, typename PT4>
358class PointerUnion4 {
359public:
360 using InnerUnion1 = PointerUnion<PT1, PT2>;
361 using InnerUnion2 = PointerUnion<PT3, PT4>;
362 using ValTy = PointerUnion<InnerUnion1, InnerUnion2>;
363
364private:
365 ValTy Val;
366
367public:
368 PointerUnion4() = default;
369 PointerUnion4(PT1 V) { Val = InnerUnion1(V); }
370 PointerUnion4(PT2 V) { Val = InnerUnion1(V); }
371 PointerUnion4(PT3 V) { Val = InnerUnion2(V); }
372 PointerUnion4(PT4 V) { Val = InnerUnion2(V); }
373
374 /// Test if the pointer held in the union is null, regardless of
375 /// which type it is.
376 bool isNull() const { return Val.isNull(); }
377 explicit operator bool() const { return !isNull(); }
378
379 /// Test if the Union currently holds the type matching T.
380 template <typename T> int is() const {
381 // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
382 using Ty = typename ::llvm::PointerUnionTypeSelector<
383 PT1, T, InnerUnion1,
384 ::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1,
385 InnerUnion2>>::Return;
386 return Val.template is<Ty>() && Val.template get<Ty>().template is<T>();
387 }
388
389 /// Returns the value of the specified pointer type.
390 ///
391 /// If the specified pointer type is incorrect, assert.
392 template <typename T> T get() const {
393 assert(is<T>() && "Invalid accessor called");
394 // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
395 using Ty = typename ::llvm::PointerUnionTypeSelector<
396 PT1, T, InnerUnion1,
397 ::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1,
398 InnerUnion2>>::Return;
399 return Val.template get<Ty>().template get<T>();
400 }
401
402 /// Returns the current pointer if it is of the specified pointer type,
403 /// otherwises returns null.
404 template <typename T> T dyn_cast() const {
405 if (is<T>())
406 return get<T>();
407 return T();
408 }
409
410 /// Assignment from nullptr which just clears the union.
411 const PointerUnion4 &operator=(std::nullptr_t) {
412 Val = nullptr;
413 return *this;
414 }
415
416 /// Assignment operators - Allow assigning into this union from either
417 /// pointer type, setting the discriminator to remember what it came from.
418 const PointerUnion4 &operator=(const PT1 &RHS) {
419 Val = InnerUnion1(RHS);
420 return *this;
421 }
422 const PointerUnion4 &operator=(const PT2 &RHS) {
423 Val = InnerUnion1(RHS);
424 return *this;
425 }
426 const PointerUnion4 &operator=(const PT3 &RHS) {
427 Val = InnerUnion2(RHS);
428 return *this;
429 }
430 const PointerUnion4 &operator=(const PT4 &RHS) {
431 Val = InnerUnion2(RHS);
432 return *this;
433 }
434
435 void *getOpaqueValue() const { return Val.getOpaqueValue(); }
436 static inline PointerUnion4 getFromOpaqueValue(void *VP) {
437 PointerUnion4 V;
438 V.Val = ValTy::getFromOpaqueValue(VP);
439 return V;
440 }
441};
442
443// Teach SmallPtrSet that PointerUnion4 is "basically a pointer", that has
444// # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
445template <typename PT1, typename PT2, typename PT3, typename PT4>
446struct PointerLikeTypeTraits<PointerUnion4<PT1, PT2, PT3, PT4>> {
447 static inline void *
448 getAsVoidPointer(const PointerUnion4<PT1, PT2, PT3, PT4> &P) {
449 return P.getOpaqueValue();
450 }
451
452 static inline PointerUnion4<PT1, PT2, PT3, PT4> getFromVoidPointer(void *P) {
453 return PointerUnion4<PT1, PT2, PT3, PT4>::getFromOpaqueValue(P);
454 }
455
456 // The number of bits available are the min of the two pointer types.
457 enum {
458 NumLowBitsAvailable = PointerLikeTypeTraits<
459 typename PointerUnion4<PT1, PT2, PT3, PT4>::ValTy>::NumLowBitsAvailable
460 };
461};
462
463// Teach DenseMap how to use PointerUnions as keys.
464template <typename T, typename U> struct DenseMapInfo<PointerUnion<T, U>> {
465 using Pair = PointerUnion<T, U>;
466 using FirstInfo = DenseMapInfo<T>;
467 using SecondInfo = DenseMapInfo<U>;
468
469 static inline Pair getEmptyKey() { return Pair(FirstInfo::getEmptyKey()); }
470
471 static inline Pair getTombstoneKey() {
472 return Pair(FirstInfo::getTombstoneKey());
473 }
474
475 static unsigned getHashValue(const Pair &PairVal) {
476 intptr_t key = (intptr_t)PairVal.getOpaqueValue();
477 return DenseMapInfo<intptr_t>::getHashValue(key);
478 }
479
480 static bool isEqual(const Pair &LHS, const Pair &RHS) {
481 return LHS.template is<T>() == RHS.template is<T>() &&
482 (LHS.template is<T>() ? FirstInfo::isEqual(LHS.template get<T>(),
483 RHS.template get<T>())
484 : SecondInfo::isEqual(LHS.template get<U>(),
485 RHS.template get<U>()));
486 }
487};
488
489} // end namespace llvm
490
491#endif // LLVM_ADT_POINTERUNION_H
492

Warning: That file was not part of the compilation database. It may have many parsing errors.