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 <cstdint>
23#include <cstddef>
24
25namespace llvm {
26
27template <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.
40template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
41struct PointerUnionTypeSelector {
42 typedef typename PointerUnionTypeSelectorReturn<RET_NE>::Return Return;
43};
44
45template <typename T, typename RET_EQ, typename RET_NE>
46struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
47 typedef typename PointerUnionTypeSelectorReturn<RET_EQ>::Return 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 typedef
54 typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return 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 typedef PointerIntPair<void *, 1, bool, PointerUnionUIntTraits<PT1, PT2>>
90 ValTy;
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
106 PointerUnion(PT1 V)
107 : Val(const_cast<void *>(
108 PointerLikeTypeTraits<PT1>::getAsVoidPointer(V))) {}
109 PointerUnion(PT2 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.
118 return !PointerLikeTypeTraits<PT1>::getFromVoidPointer(Val.getPointer());
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");
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 (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
192template <typename PT1, typename PT2>
193static bool operator==(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
194 return lhs.getOpaqueValue() == rhs.getOpaqueValue();
195}
196
197template <typename PT1, typename PT2>
198static bool operator!=(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
199 return lhs.getOpaqueValue() != rhs.getOpaqueValue();
200}
201
202template <typename PT1, typename PT2>
203static 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.
209template <typename PT1, typename PT2>
210class PointerLikeTypeTraits<PointerUnion<PT1, PT2>> {
211public:
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 typedef PointerUnion<PT1, PT2> InnerUnion;
232 typedef PointerUnion<InnerUnion, PT3> ValTy;
233
234private:
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
256public:
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,
273 ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3>>::Return
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,
286 ::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3>>::Return
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.
330template <typename PT1, typename PT2, typename PT3>
331class PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3>> {
332public:
333 static inline void *getAsVoidPointer(const PointerUnion3<PT1, PT2, PT3> &P) {
334 return P.getOpaqueValue();
335 }
336
337 static inline PointerUnion3<PT1, PT2, PT3> getFromVoidPointer(void *P) {
338 return PointerUnion3<PT1, PT2, PT3>::getFromOpaqueValue(P);
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.
350template <typename PT1, typename PT2, typename PT3, typename PT4>
351class PointerUnion4 {
352public:
353 typedef PointerUnion<PT1, PT2> InnerUnion1;
354 typedef PointerUnion<PT3, PT4> InnerUnion2;
355 typedef PointerUnion<InnerUnion1, InnerUnion2> ValTy;
356
357private:
358 ValTy Val;
359
360public:
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<
377 PT1, T, InnerUnion1, ::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<
389 PT1, T, InnerUnion1, ::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.
437template <typename PT1, typename PT2, typename PT3, typename PT4>
438class PointerLikeTypeTraits<PointerUnion4<PT1, PT2, PT3, PT4>> {
439public:
440 static inline void *
441 getAsVoidPointer(const PointerUnion4<PT1, PT2, PT3, PT4> &P) {
442 return P.getOpaqueValue();
443 }
444
445 static inline PointerUnion4<PT1, PT2, PT3, PT4> getFromVoidPointer(void *P) {
446 return PointerUnion4<PT1, PT2, PT3, PT4>::getFromOpaqueValue(P);
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.
457template <typename T, typename U> struct DenseMapInfo<PointerUnion<T, U>> {
458 typedef PointerUnion<T, U> Pair;
459 typedef DenseMapInfo<T> FirstInfo;
460 typedef DenseMapInfo<U> SecondInfo;
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();
468 return DenseMapInfo<intptr_t>::getHashValue(Val: key);
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
482

source code of flutter_engine/third_party/swiftshader/third_party/llvm-subzero/include/llvm/ADT/PointerUnion.h