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1 //===- AttributeDetail.h - MLIR Affine Map details Class --------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This holds implementation details of Attribute.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef ATTRIBUTEDETAIL_H_
14 #define ATTRIBUTEDETAIL_H_
15 
16 #include "mlir/IR/AffineMap.h"
17 #include "mlir/IR/BuiltinAttributes.h"
18 #include "mlir/IR/BuiltinTypes.h"
19 #include "mlir/IR/Identifier.h"
20 #include "mlir/IR/IntegerSet.h"
21 #include "mlir/IR/MLIRContext.h"
22 #include "mlir/Support/StorageUniquer.h"
23 #include "llvm/ADT/APFloat.h"
24 #include "llvm/ADT/PointerIntPair.h"
25 #include "llvm/Support/TrailingObjects.h"
26 
27 namespace mlir {
28 namespace detail {
29 // An attribute representing a reference to an affine map.
30 struct AffineMapAttributeStorage : public AttributeStorage {
31   using KeyTy = AffineMap;
32 
AffineMapAttributeStorageAffineMapAttributeStorage33   AffineMapAttributeStorage(AffineMap value)
34       : AttributeStorage(IndexType::get(value.getContext())), value(value) {}
35 
36   /// Key equality function.
37   bool operator==(const KeyTy &key) const { return key == value; }
38 
39   /// Construct a new storage instance.
40   static AffineMapAttributeStorage *
constructAffineMapAttributeStorage41   construct(AttributeStorageAllocator &allocator, KeyTy key) {
42     return new (allocator.allocate<AffineMapAttributeStorage>())
43         AffineMapAttributeStorage(key);
44   }
45 
46   AffineMap value;
47 };
48 
49 /// An attribute representing an array of other attributes.
50 struct ArrayAttributeStorage : public AttributeStorage {
51   using KeyTy = ArrayRef<Attribute>;
52 
ArrayAttributeStorageArrayAttributeStorage53   ArrayAttributeStorage(ArrayRef<Attribute> value) : value(value) {}
54 
55   /// Key equality function.
56   bool operator==(const KeyTy &key) const { return key == value; }
57 
58   /// Construct a new storage instance.
constructArrayAttributeStorage59   static ArrayAttributeStorage *construct(AttributeStorageAllocator &allocator,
60                                           const KeyTy &key) {
61     return new (allocator.allocate<ArrayAttributeStorage>())
62         ArrayAttributeStorage(allocator.copyInto(key));
63   }
64 
65   ArrayRef<Attribute> value;
66 };
67 
68 /// An attribute representing a dictionary of sorted named attributes.
69 struct DictionaryAttributeStorage final
70     : public AttributeStorage,
71       private llvm::TrailingObjects<DictionaryAttributeStorage,
72                                     NamedAttribute> {
73   using KeyTy = ArrayRef<NamedAttribute>;
74 
75   /// Given a list of NamedAttribute's, canonicalize the list (sorting
76   /// by name) and return the unique'd result.
77   static DictionaryAttributeStorage *get(ArrayRef<NamedAttribute> attrs);
78 
79   /// Key equality function.
80   bool operator==(const KeyTy &key) const { return key == getElements(); }
81 
82   /// Construct a new storage instance.
83   static DictionaryAttributeStorage *
constructfinal84   construct(AttributeStorageAllocator &allocator, const KeyTy &key) {
85     auto size = DictionaryAttributeStorage::totalSizeToAlloc<NamedAttribute>(
86         key.size());
87     auto rawMem = allocator.allocate(size, alignof(DictionaryAttributeStorage));
88 
89     // Initialize the storage and trailing attribute list.
90     auto result = ::new (rawMem) DictionaryAttributeStorage(key.size());
91     std::uninitialized_copy(key.begin(), key.end(),
92                             result->getTrailingObjects<NamedAttribute>());
93     return result;
94   }
95 
96   /// Return the elements of this dictionary attribute.
getElementsfinal97   ArrayRef<NamedAttribute> getElements() const {
98     return {getTrailingObjects<NamedAttribute>(), numElements};
99   }
100 
101 private:
102   friend class llvm::TrailingObjects<DictionaryAttributeStorage,
103                                      NamedAttribute>;
104 
105   // This is used by the llvm::TrailingObjects base class.
numTrailingObjectsfinal106   size_t numTrailingObjects(OverloadToken<NamedAttribute>) const {
107     return numElements;
108   }
DictionaryAttributeStoragefinal109   DictionaryAttributeStorage(unsigned numElements) : numElements(numElements) {}
110 
111   /// This is the number of attributes.
112   const unsigned numElements;
113 };
114 
115 /// An attribute representing a floating point value.
116 struct FloatAttributeStorage final
117     : public AttributeStorage,
118       public llvm::TrailingObjects<FloatAttributeStorage, uint64_t> {
119   using KeyTy = std::pair<Type, APFloat>;
120 
FloatAttributeStoragefinal121   FloatAttributeStorage(const llvm::fltSemantics &semantics, Type type,
122                         size_t numObjects)
123       : AttributeStorage(type), semantics(semantics), numObjects(numObjects) {}
124 
125   /// Key equality and hash functions.
126   bool operator==(const KeyTy &key) const {
127     return key.first == getType() && key.second.bitwiseIsEqual(getValue());
128   }
hashKeyfinal129   static unsigned hashKey(const KeyTy &key) {
130     return llvm::hash_combine(key.first, llvm::hash_value(key.second));
131   }
132 
133   /// Construct a key with a type and double.
getKeyfinal134   static KeyTy getKey(Type type, double value) {
135     if (type.isF64())
136       return KeyTy(type, APFloat(value));
137 
138     // This handles, e.g., F16 because there is no APFloat constructor for it.
139     bool unused;
140     APFloat val(value);
141     val.convert(type.cast<FloatType>().getFloatSemantics(),
142                 APFloat::rmNearestTiesToEven, &unused);
143     return KeyTy(type, val);
144   }
145 
146   /// Construct a new storage instance.
constructfinal147   static FloatAttributeStorage *construct(AttributeStorageAllocator &allocator,
148                                           const KeyTy &key) {
149     const auto &apint = key.second.bitcastToAPInt();
150 
151     // Here one word's bitwidth equals to that of uint64_t.
152     auto elements = ArrayRef<uint64_t>(apint.getRawData(), apint.getNumWords());
153 
154     auto byteSize =
155         FloatAttributeStorage::totalSizeToAlloc<uint64_t>(elements.size());
156     auto rawMem = allocator.allocate(byteSize, alignof(FloatAttributeStorage));
157     auto result = ::new (rawMem) FloatAttributeStorage(
158         key.second.getSemantics(), key.first, elements.size());
159     std::uninitialized_copy(elements.begin(), elements.end(),
160                             result->getTrailingObjects<uint64_t>());
161     return result;
162   }
163 
164   /// Returns an APFloat representing the stored value.
getValuefinal165   APFloat getValue() const {
166     auto val = APInt(APFloat::getSizeInBits(semantics),
167                      {getTrailingObjects<uint64_t>(), numObjects});
168     return APFloat(semantics, val);
169   }
170 
171   const llvm::fltSemantics &semantics;
172   size_t numObjects;
173 };
174 
175 /// An attribute representing an integral value.
176 struct IntegerAttributeStorage final
177     : public AttributeStorage,
178       public llvm::TrailingObjects<IntegerAttributeStorage, uint64_t> {
179   using KeyTy = std::pair<Type, APInt>;
180 
IntegerAttributeStoragefinal181   IntegerAttributeStorage(Type type, size_t numObjects)
182       : AttributeStorage(type), numObjects(numObjects) {
183     assert((type.isIndex() || type.isa<IntegerType>()) && "invalid type");
184   }
185 
186   /// Key equality and hash functions.
187   bool operator==(const KeyTy &key) const {
188     return key == KeyTy(getType(), getValue());
189   }
hashKeyfinal190   static unsigned hashKey(const KeyTy &key) {
191     return llvm::hash_combine(key.first, llvm::hash_value(key.second));
192   }
193 
194   /// Construct a new storage instance.
195   static IntegerAttributeStorage *
constructfinal196   construct(AttributeStorageAllocator &allocator, const KeyTy &key) {
197     Type type;
198     APInt value;
199     std::tie(type, value) = key;
200 
201     auto elements = ArrayRef<uint64_t>(value.getRawData(), value.getNumWords());
202     auto size =
203         IntegerAttributeStorage::totalSizeToAlloc<uint64_t>(elements.size());
204     auto rawMem = allocator.allocate(size, alignof(IntegerAttributeStorage));
205     auto result = ::new (rawMem) IntegerAttributeStorage(type, elements.size());
206     std::uninitialized_copy(elements.begin(), elements.end(),
207                             result->getTrailingObjects<uint64_t>());
208     return result;
209   }
210 
211   /// Returns an APInt representing the stored value.
getValuefinal212   APInt getValue() const {
213     if (getType().isIndex())
214       return APInt(64, {getTrailingObjects<uint64_t>(), numObjects});
215     return APInt(getType().getIntOrFloatBitWidth(),
216                  {getTrailingObjects<uint64_t>(), numObjects});
217   }
218 
219   size_t numObjects;
220 };
221 
222 // An attribute representing a reference to an integer set.
223 struct IntegerSetAttributeStorage : public AttributeStorage {
224   using KeyTy = IntegerSet;
225 
IntegerSetAttributeStorageIntegerSetAttributeStorage226   IntegerSetAttributeStorage(IntegerSet value) : value(value) {}
227 
228   /// Key equality function.
229   bool operator==(const KeyTy &key) const { return key == value; }
230 
231   /// Construct a new storage instance.
232   static IntegerSetAttributeStorage *
constructIntegerSetAttributeStorage233   construct(AttributeStorageAllocator &allocator, KeyTy key) {
234     return new (allocator.allocate<IntegerSetAttributeStorage>())
235         IntegerSetAttributeStorage(key);
236   }
237 
238   IntegerSet value;
239 };
240 
241 /// Opaque Attribute Storage and Uniquing.
242 struct OpaqueAttributeStorage : public AttributeStorage {
OpaqueAttributeStorageOpaqueAttributeStorage243   OpaqueAttributeStorage(Identifier dialectNamespace, StringRef attrData,
244                          Type type)
245       : AttributeStorage(type), dialectNamespace(dialectNamespace),
246         attrData(attrData) {}
247 
248   /// The hash key used for uniquing.
249   using KeyTy = std::tuple<Identifier, StringRef, Type>;
250   bool operator==(const KeyTy &key) const {
251     return key == KeyTy(dialectNamespace, attrData, getType());
252   }
253 
constructOpaqueAttributeStorage254   static OpaqueAttributeStorage *construct(AttributeStorageAllocator &allocator,
255                                            const KeyTy &key) {
256     return new (allocator.allocate<OpaqueAttributeStorage>())
257         OpaqueAttributeStorage(std::get<0>(key),
258                                allocator.copyInto(std::get<1>(key)),
259                                std::get<2>(key));
260   }
261 
262   // The dialect namespace.
263   Identifier dialectNamespace;
264 
265   // The parser attribute data for this opaque attribute.
266   StringRef attrData;
267 };
268 
269 /// An attribute representing a string value.
270 struct StringAttributeStorage : public AttributeStorage {
271   using KeyTy = std::pair<StringRef, Type>;
272 
StringAttributeStorageStringAttributeStorage273   StringAttributeStorage(StringRef value, Type type)
274       : AttributeStorage(type), value(value) {}
275 
276   /// Key equality function.
277   bool operator==(const KeyTy &key) const {
278     return key == KeyTy(value, getType());
279   }
280 
281   /// Construct a new storage instance.
constructStringAttributeStorage282   static StringAttributeStorage *construct(AttributeStorageAllocator &allocator,
283                                            const KeyTy &key) {
284     return new (allocator.allocate<StringAttributeStorage>())
285         StringAttributeStorage(allocator.copyInto(key.first), key.second);
286   }
287 
288   StringRef value;
289 };
290 
291 /// An attribute representing a symbol reference.
292 struct SymbolRefAttributeStorage final
293     : public AttributeStorage,
294       public llvm::TrailingObjects<SymbolRefAttributeStorage,
295                                    FlatSymbolRefAttr> {
296   using KeyTy = std::pair<StringRef, ArrayRef<FlatSymbolRefAttr>>;
297 
SymbolRefAttributeStoragefinal298   SymbolRefAttributeStorage(StringRef value, size_t numNestedRefs)
299       : value(value), numNestedRefs(numNestedRefs) {}
300 
301   /// Key equality function.
302   bool operator==(const KeyTy &key) const {
303     return key == KeyTy(value, getNestedRefs());
304   }
305 
306   /// Construct a new storage instance.
307   static SymbolRefAttributeStorage *
constructfinal308   construct(AttributeStorageAllocator &allocator, const KeyTy &key) {
309     auto size = SymbolRefAttributeStorage::totalSizeToAlloc<FlatSymbolRefAttr>(
310         key.second.size());
311     auto rawMem = allocator.allocate(size, alignof(SymbolRefAttributeStorage));
312     auto result = ::new (rawMem) SymbolRefAttributeStorage(
313         allocator.copyInto(key.first), key.second.size());
314     std::uninitialized_copy(key.second.begin(), key.second.end(),
315                             result->getTrailingObjects<FlatSymbolRefAttr>());
316     return result;
317   }
318 
319   /// Returns the set of nested references.
getNestedRefsfinal320   ArrayRef<FlatSymbolRefAttr> getNestedRefs() const {
321     return {getTrailingObjects<FlatSymbolRefAttr>(), numNestedRefs};
322   }
323 
324   StringRef value;
325   size_t numNestedRefs;
326 };
327 
328 /// An attribute representing a reference to a type.
329 struct TypeAttributeStorage : public AttributeStorage {
330   using KeyTy = Type;
331 
TypeAttributeStorageTypeAttributeStorage332   TypeAttributeStorage(Type value) : value(value) {}
333 
334   /// Key equality function.
335   bool operator==(const KeyTy &key) const { return key == value; }
336 
337   /// Construct a new storage instance.
constructTypeAttributeStorage338   static TypeAttributeStorage *construct(AttributeStorageAllocator &allocator,
339                                          KeyTy key) {
340     return new (allocator.allocate<TypeAttributeStorage>())
341         TypeAttributeStorage(key);
342   }
343 
344   Type value;
345 };
346 
347 //===----------------------------------------------------------------------===//
348 // Elements Attributes
349 //===----------------------------------------------------------------------===//
350 
351 /// Return the bit width which DenseElementsAttr should use for this type.
getDenseElementBitWidth(Type eltType)352 inline size_t getDenseElementBitWidth(Type eltType) {
353   // Align the width for complex to 8 to make storage and interpretation easier.
354   if (ComplexType comp = eltType.dyn_cast<ComplexType>())
355     return llvm::alignTo<8>(getDenseElementBitWidth(comp.getElementType())) * 2;
356   if (eltType.isIndex())
357     return IndexType::kInternalStorageBitWidth;
358   return eltType.getIntOrFloatBitWidth();
359 }
360 
361 /// An attribute representing a reference to a dense vector or tensor object.
362 struct DenseElementsAttributeStorage : public AttributeStorage {
363 public:
DenseElementsAttributeStorageDenseElementsAttributeStorage364   DenseElementsAttributeStorage(ShapedType ty, bool isSplat)
365       : AttributeStorage(ty), isSplat(isSplat) {}
366 
367   bool isSplat;
368 };
369 
370 /// An attribute representing a reference to a dense vector or tensor object.
371 struct DenseIntOrFPElementsAttributeStorage
372     : public DenseElementsAttributeStorage {
373   DenseIntOrFPElementsAttributeStorage(ShapedType ty, ArrayRef<char> data,
374                                        bool isSplat = false)
DenseElementsAttributeStorageDenseIntOrFPElementsAttributeStorage375       : DenseElementsAttributeStorage(ty, isSplat), data(data) {}
376 
377   struct KeyTy {
378     KeyTy(ShapedType type, ArrayRef<char> data, llvm::hash_code hashCode,
379           bool isSplat = false)
typeDenseIntOrFPElementsAttributeStorage::KeyTy380         : type(type), data(data), hashCode(hashCode), isSplat(isSplat) {}
381 
382     /// The type of the dense elements.
383     ShapedType type;
384 
385     /// The raw buffer for the data storage.
386     ArrayRef<char> data;
387 
388     /// The computed hash code for the storage data.
389     llvm::hash_code hashCode;
390 
391     /// A boolean that indicates if this data is a splat or not.
392     bool isSplat;
393   };
394 
395   /// Compare this storage instance with the provided key.
396   bool operator==(const KeyTy &key) const {
397     if (key.type != getType())
398       return false;
399 
400     // For boolean splats we need to explicitly check that the first bit is the
401     // same. Boolean values are packed at the bit level, and even though a splat
402     // is detected the rest of the bits in the first byte may differ from the
403     // splat value.
404     if (key.type.getElementType().isInteger(1)) {
405       if (key.isSplat != isSplat)
406         return false;
407       if (isSplat)
408         return (key.data.front() & 1) == data.front();
409     }
410 
411     // Otherwise, we can default to just checking the data.
412     return key.data == data;
413   }
414 
415   /// Construct a key from a shaped type, raw data buffer, and a flag that
416   /// signals if the data is already known to be a splat. Callers to this
417   /// function are expected to tag preknown splat values when possible, e.g. one
418   /// element shapes.
getKeyDenseIntOrFPElementsAttributeStorage419   static KeyTy getKey(ShapedType ty, ArrayRef<char> data, bool isKnownSplat) {
420     // Handle an empty storage instance.
421     if (data.empty())
422       return KeyTy(ty, data, 0);
423 
424     // If the data is already known to be a splat, the key hash value is
425     // directly the data buffer.
426     if (isKnownSplat)
427       return KeyTy(ty, data, llvm::hash_value(data), isKnownSplat);
428 
429     // Otherwise, we need to check if the data corresponds to a splat or not.
430 
431     // Handle the simple case of only one element.
432     size_t numElements = ty.getNumElements();
433     assert(numElements != 1 && "splat of 1 element should already be detected");
434 
435     // Handle boolean values directly as they are packed to 1-bit.
436     if (ty.getElementType().isInteger(1) == 1)
437       return getKeyForBoolData(ty, data, numElements);
438 
439     size_t elementWidth = getDenseElementBitWidth(ty.getElementType());
440     // Non 1-bit dense elements are padded to 8-bits.
441     size_t storageSize = llvm::divideCeil(elementWidth, CHAR_BIT);
442     assert(((data.size() / storageSize) == numElements) &&
443            "data does not hold expected number of elements");
444 
445     // Create the initial hash value with just the first element.
446     auto firstElt = data.take_front(storageSize);
447     auto hashVal = llvm::hash_value(firstElt);
448 
449     // Check to see if this storage represents a splat. If it doesn't then
450     // combine the hash for the data starting with the first non splat element.
451     for (size_t i = storageSize, e = data.size(); i != e; i += storageSize)
452       if (memcmp(data.data(), &data[i], storageSize))
453         return KeyTy(ty, data, llvm::hash_combine(hashVal, data.drop_front(i)));
454 
455     // Otherwise, this is a splat so just return the hash of the first element.
456     return KeyTy(ty, firstElt, hashVal, /*isSplat=*/true);
457   }
458 
459   /// Construct a key with a set of boolean data.
getKeyForBoolDataDenseIntOrFPElementsAttributeStorage460   static KeyTy getKeyForBoolData(ShapedType ty, ArrayRef<char> data,
461                                  size_t numElements) {
462     ArrayRef<char> splatData = data;
463     bool splatValue = splatData.front() & 1;
464 
465     // Helper functor to generate a KeyTy for a boolean splat value.
466     auto generateSplatKey = [=] {
467       return KeyTy(ty, data.take_front(1),
468                    llvm::hash_value(ArrayRef<char>(splatValue ? 1 : 0)),
469                    /*isSplat=*/true);
470     };
471 
472     // Handle the case where the potential splat value is 1 and the number of
473     // elements is non 8-bit aligned.
474     size_t numOddElements = numElements % CHAR_BIT;
475     if (splatValue && numOddElements != 0) {
476       // Check that all bits are set in the last value.
477       char lastElt = splatData.back();
478       if (lastElt != llvm::maskTrailingOnes<unsigned char>(numOddElements))
479         return KeyTy(ty, data, llvm::hash_value(data));
480 
481       // If this is the only element, the data is known to be a splat.
482       if (splatData.size() == 1)
483         return generateSplatKey();
484       splatData = splatData.drop_back();
485     }
486 
487     // Check that the data buffer corresponds to a splat of the proper mask.
488     char mask = splatValue ? ~0 : 0;
489     return llvm::all_of(splatData, [mask](char c) { return c == mask; })
490                ? generateSplatKey()
491                : KeyTy(ty, data, llvm::hash_value(data));
492   }
493 
494   /// Hash the key for the storage.
hashKeyDenseIntOrFPElementsAttributeStorage495   static llvm::hash_code hashKey(const KeyTy &key) {
496     return llvm::hash_combine(key.type, key.hashCode);
497   }
498 
499   /// Construct a new storage instance.
500   static DenseIntOrFPElementsAttributeStorage *
constructDenseIntOrFPElementsAttributeStorage501   construct(AttributeStorageAllocator &allocator, KeyTy key) {
502     // If the data buffer is non-empty, we copy it into the allocator with a
503     // 64-bit alignment.
504     ArrayRef<char> copy, data = key.data;
505     if (!data.empty()) {
506       char *rawData = reinterpret_cast<char *>(
507           allocator.allocate(data.size(), alignof(uint64_t)));
508       std::memcpy(rawData, data.data(), data.size());
509 
510       // If this is a boolean splat, make sure only the first bit is used.
511       if (key.isSplat && key.type.getElementType().isInteger(1))
512         rawData[0] &= 1;
513       copy = ArrayRef<char>(rawData, data.size());
514     }
515 
516     return new (allocator.allocate<DenseIntOrFPElementsAttributeStorage>())
517         DenseIntOrFPElementsAttributeStorage(key.type, copy, key.isSplat);
518   }
519 
520   ArrayRef<char> data;
521 };
522 
523 /// An attribute representing a reference to a dense vector or tensor object
524 /// containing strings.
525 struct DenseStringElementsAttributeStorage
526     : public DenseElementsAttributeStorage {
527   DenseStringElementsAttributeStorage(ShapedType ty, ArrayRef<StringRef> data,
528                                       bool isSplat = false)
DenseElementsAttributeStorageDenseStringElementsAttributeStorage529       : DenseElementsAttributeStorage(ty, isSplat), data(data) {}
530 
531   struct KeyTy {
532     KeyTy(ShapedType type, ArrayRef<StringRef> data, llvm::hash_code hashCode,
533           bool isSplat = false)
typeDenseStringElementsAttributeStorage::KeyTy534         : type(type), data(data), hashCode(hashCode), isSplat(isSplat) {}
535 
536     /// The type of the dense elements.
537     ShapedType type;
538 
539     /// The raw buffer for the data storage.
540     ArrayRef<StringRef> data;
541 
542     /// The computed hash code for the storage data.
543     llvm::hash_code hashCode;
544 
545     /// A boolean that indicates if this data is a splat or not.
546     bool isSplat;
547   };
548 
549   /// Compare this storage instance with the provided key.
550   bool operator==(const KeyTy &key) const {
551     if (key.type != getType())
552       return false;
553 
554     // Otherwise, we can default to just checking the data. StringRefs compare
555     // by contents.
556     return key.data == data;
557   }
558 
559   /// Construct a key from a shaped type, StringRef data buffer, and a flag that
560   /// signals if the data is already known to be a splat. Callers to this
561   /// function are expected to tag preknown splat values when possible, e.g. one
562   /// element shapes.
getKeyDenseStringElementsAttributeStorage563   static KeyTy getKey(ShapedType ty, ArrayRef<StringRef> data,
564                       bool isKnownSplat) {
565     // Handle an empty storage instance.
566     if (data.empty())
567       return KeyTy(ty, data, 0);
568 
569     // If the data is already known to be a splat, the key hash value is
570     // directly the data buffer.
571     if (isKnownSplat)
572       return KeyTy(ty, data, llvm::hash_value(data.front()), isKnownSplat);
573 
574     // Handle the simple case of only one element.
575     assert(ty.getNumElements() != 1 &&
576            "splat of 1 element should already be detected");
577 
578     // Create the initial hash value with just the first element.
579     const auto &firstElt = data.front();
580     auto hashVal = llvm::hash_value(firstElt);
581 
582     // Check to see if this storage represents a splat. If it doesn't then
583     // combine the hash for the data starting with the first non splat element.
584     for (size_t i = 1, e = data.size(); i != e; i++)
585       if (!firstElt.equals(data[i]))
586         return KeyTy(ty, data, llvm::hash_combine(hashVal, data.drop_front(i)));
587 
588     // Otherwise, this is a splat so just return the hash of the first element.
589     return KeyTy(ty, data.take_front(), hashVal, /*isSplat=*/true);
590   }
591 
592   /// Hash the key for the storage.
hashKeyDenseStringElementsAttributeStorage593   static llvm::hash_code hashKey(const KeyTy &key) {
594     return llvm::hash_combine(key.type, key.hashCode);
595   }
596 
597   /// Construct a new storage instance.
598   static DenseStringElementsAttributeStorage *
constructDenseStringElementsAttributeStorage599   construct(AttributeStorageAllocator &allocator, KeyTy key) {
600     // If the data buffer is non-empty, we copy it into the allocator with a
601     // 64-bit alignment.
602     ArrayRef<StringRef> copy, data = key.data;
603     if (data.empty()) {
604       return new (allocator.allocate<DenseStringElementsAttributeStorage>())
605           DenseStringElementsAttributeStorage(key.type, copy, key.isSplat);
606     }
607 
608     int numEntries = key.isSplat ? 1 : data.size();
609 
610     // Compute the amount data needed to store the ArrayRef and StringRef
611     // contents.
612     size_t dataSize = sizeof(StringRef) * numEntries;
613     for (int i = 0; i < numEntries; i++)
614       dataSize += data[i].size();
615 
616     char *rawData = reinterpret_cast<char *>(
617         allocator.allocate(dataSize, alignof(uint64_t)));
618 
619     // Setup a mutable array ref of our string refs so that we can update their
620     // contents.
621     auto mutableCopy = MutableArrayRef<StringRef>(
622         reinterpret_cast<StringRef *>(rawData), numEntries);
623     auto stringData = rawData + numEntries * sizeof(StringRef);
624 
625     for (int i = 0; i < numEntries; i++) {
626       memcpy(stringData, data[i].data(), data[i].size());
627       mutableCopy[i] = StringRef(stringData, data[i].size());
628       stringData += data[i].size();
629     }
630 
631     copy =
632         ArrayRef<StringRef>(reinterpret_cast<StringRef *>(rawData), numEntries);
633 
634     return new (allocator.allocate<DenseStringElementsAttributeStorage>())
635         DenseStringElementsAttributeStorage(key.type, copy, key.isSplat);
636   }
637 
638   ArrayRef<StringRef> data;
639 };
640 
641 /// An attribute representing a reference to a tensor constant with opaque
642 /// content.
643 struct OpaqueElementsAttributeStorage : public AttributeStorage {
644   using KeyTy = std::tuple<Type, Dialect *, StringRef>;
645 
OpaqueElementsAttributeStorageOpaqueElementsAttributeStorage646   OpaqueElementsAttributeStorage(Type type, Dialect *dialect, StringRef bytes)
647       : AttributeStorage(type), dialect(dialect), bytes(bytes) {}
648 
649   /// Key equality and hash functions.
650   bool operator==(const KeyTy &key) const {
651     return key == std::make_tuple(getType(), dialect, bytes);
652   }
hashKeyOpaqueElementsAttributeStorage653   static unsigned hashKey(const KeyTy &key) {
654     return llvm::hash_combine(std::get<0>(key), std::get<1>(key),
655                               std::get<2>(key));
656   }
657 
658   /// Construct a new storage instance.
659   static OpaqueElementsAttributeStorage *
constructOpaqueElementsAttributeStorage660   construct(AttributeStorageAllocator &allocator, KeyTy key) {
661     // TODO: Provide a way to avoid copying content of large opaque
662     // tensors This will likely require a new reference attribute kind.
663     return new (allocator.allocate<OpaqueElementsAttributeStorage>())
664         OpaqueElementsAttributeStorage(std::get<0>(key), std::get<1>(key),
665                                        allocator.copyInto(std::get<2>(key)));
666   }
667 
668   Dialect *dialect;
669   StringRef bytes;
670 };
671 
672 /// An attribute representing a reference to a sparse vector or tensor object.
673 struct SparseElementsAttributeStorage : public AttributeStorage {
674   using KeyTy = std::tuple<Type, DenseIntElementsAttr, DenseElementsAttr>;
675 
SparseElementsAttributeStorageSparseElementsAttributeStorage676   SparseElementsAttributeStorage(Type type, DenseIntElementsAttr indices,
677                                  DenseElementsAttr values)
678       : AttributeStorage(type), indices(indices), values(values) {}
679 
680   /// Key equality and hash functions.
681   bool operator==(const KeyTy &key) const {
682     return key == std::make_tuple(getType(), indices, values);
683   }
hashKeySparseElementsAttributeStorage684   static unsigned hashKey(const KeyTy &key) {
685     return llvm::hash_combine(std::get<0>(key), std::get<1>(key),
686                               std::get<2>(key));
687   }
688 
689   /// Construct a new storage instance.
690   static SparseElementsAttributeStorage *
constructSparseElementsAttributeStorage691   construct(AttributeStorageAllocator &allocator, KeyTy key) {
692     return new (allocator.allocate<SparseElementsAttributeStorage>())
693         SparseElementsAttributeStorage(std::get<0>(key), std::get<1>(key),
694                                        std::get<2>(key));
695   }
696 
697   DenseIntElementsAttr indices;
698   DenseElementsAttr values;
699 };
700 } // namespace detail
701 } // namespace mlir
702 
703 #endif // ATTRIBUTEDETAIL_H_
704