1 //===- MLIRContext.cpp - MLIR Type Classes --------------------------------===//
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 #include "mlir/IR/MLIRContext.h"
10 #include "AffineExprDetail.h"
11 #include "AffineMapDetail.h"
12 #include "AttributeDetail.h"
13 #include "IntegerSetDetail.h"
14 #include "LocationDetail.h"
15 #include "TypeDetail.h"
16 #include "mlir/IR/AffineExpr.h"
17 #include "mlir/IR/AffineMap.h"
18 #include "mlir/IR/Attributes.h"
19 #include "mlir/IR/Diagnostics.h"
20 #include "mlir/IR/Dialect.h"
21 #include "mlir/IR/Function.h"
22 #include "mlir/IR/Identifier.h"
23 #include "mlir/IR/IntegerSet.h"
24 #include "mlir/IR/Location.h"
25 #include "mlir/IR/Module.h"
26 #include "mlir/IR/Types.h"
27 #include "llvm/ADT/DenseMap.h"
28 #include "llvm/ADT/DenseSet.h"
29 #include "llvm/ADT/SetVector.h"
30 #include "llvm/ADT/StringSet.h"
31 #include "llvm/ADT/Twine.h"
32 #include "llvm/Support/Allocator.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/RWMutex.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include <memory>
37 
38 using namespace mlir;
39 using namespace mlir::detail;
40 
41 using llvm::hash_combine;
42 using llvm::hash_combine_range;
43 
44 //===----------------------------------------------------------------------===//
45 // MLIRContext CommandLine Options
46 //===----------------------------------------------------------------------===//
47 
48 namespace {
49 /// This struct contains command line options that can be used to initialize
50 /// various bits of an MLIRContext. This uses a struct wrapper to avoid the need
51 /// for global command line options.
52 struct MLIRContextOptions {
53   llvm::cl::opt<bool> disableThreading{
54       "mlir-disable-threading",
55       llvm::cl::desc("Disabling multi-threading within MLIR")};
56 
57   llvm::cl::opt<bool> printOpOnDiagnostic{
58       "mlir-print-op-on-diagnostic",
59       llvm::cl::desc("When a diagnostic is emitted on an operation, also print "
60                      "the operation as an attached note"),
61       llvm::cl::init(true)};
62 
63   llvm::cl::opt<bool> printStackTraceOnDiagnostic{
64       "mlir-print-stacktrace-on-diagnostic",
65       llvm::cl::desc("When a diagnostic is emitted, also print the stack trace "
66                      "as an attached note")};
67 };
68 } // end anonymous namespace
69 
70 static llvm::ManagedStatic<MLIRContextOptions> clOptions;
71 
72 /// Register a set of useful command-line options that can be used to configure
73 /// various flags within the MLIRContext. These flags are used when constructing
74 /// an MLIR context for initialization.
75 void mlir::registerMLIRContextCLOptions() {
76   // Make sure that the options struct has been initialized.
77   *clOptions;
78 }
79 
80 //===----------------------------------------------------------------------===//
81 // Builtin Dialect
82 //===----------------------------------------------------------------------===//
83 
84 namespace {
85 /// A builtin dialect to define types/etc that are necessary for the validity of
86 /// the IR.
87 struct BuiltinDialect : public Dialect {
88   BuiltinDialect(MLIRContext *context) : Dialect(/*name=*/"", context) {
89     addAttributes<AffineMapAttr, ArrayAttr, DenseIntOrFPElementsAttr,
90                   DenseStringElementsAttr, DictionaryAttr, FloatAttr,
91                   SymbolRefAttr, IntegerAttr, IntegerSetAttr, OpaqueAttr,
92                   OpaqueElementsAttr, SparseElementsAttr, StringAttr, TypeAttr,
93                   UnitAttr>();
94     addAttributes<CallSiteLoc, FileLineColLoc, FusedLoc, NameLoc, OpaqueLoc,
95                   UnknownLoc>();
96 
97     addTypes<ComplexType, FloatType, FunctionType, IndexType, IntegerType,
98              MemRefType, UnrankedMemRefType, NoneType, OpaqueType,
99              RankedTensorType, TupleType, UnrankedTensorType, VectorType>();
100 
101     // TODO: These operations should be moved to a different dialect when they
102     // have been fully decoupled from the core.
103     addOperations<FuncOp, ModuleOp, ModuleTerminatorOp>();
104   }
105 };
106 } // end anonymous namespace.
107 
108 //===----------------------------------------------------------------------===//
109 // Locking Utilities
110 //===----------------------------------------------------------------------===//
111 
112 namespace {
113 /// Utility reader lock that takes a runtime flag that specifies if we really
114 /// need to lock.
115 struct ScopedReaderLock {
116   ScopedReaderLock(llvm::sys::SmartRWMutex<true> &mutexParam, bool shouldLock)
117       : mutex(shouldLock ? &mutexParam : nullptr) {
118     if (mutex)
119       mutex->lock_shared();
120   }
121   ~ScopedReaderLock() {
122     if (mutex)
123       mutex->unlock_shared();
124   }
125   llvm::sys::SmartRWMutex<true> *mutex;
126 };
127 /// Utility writer lock that takes a runtime flag that specifies if we really
128 /// need to lock.
129 struct ScopedWriterLock {
130   ScopedWriterLock(llvm::sys::SmartRWMutex<true> &mutexParam, bool shouldLock)
131       : mutex(shouldLock ? &mutexParam : nullptr) {
132     if (mutex)
133       mutex->lock();
134   }
135   ~ScopedWriterLock() {
136     if (mutex)
137       mutex->unlock();
138   }
139   llvm::sys::SmartRWMutex<true> *mutex;
140 };
141 } // end anonymous namespace.
142 
143 //===----------------------------------------------------------------------===//
144 // AffineMap and IntegerSet hashing
145 //===----------------------------------------------------------------------===//
146 
147 /// A utility function to safely get or create a uniqued instance within the
148 /// given set container.
149 template <typename ValueT, typename DenseInfoT, typename KeyT,
150           typename ConstructorFn>
151 static ValueT safeGetOrCreate(DenseSet<ValueT, DenseInfoT> &container,
152                               KeyT &&key, llvm::sys::SmartRWMutex<true> &mutex,
153                               bool threadingIsEnabled,
154                               ConstructorFn &&constructorFn) {
155   // Check for an existing instance in read-only mode.
156   if (threadingIsEnabled) {
157     llvm::sys::SmartScopedReader<true> instanceLock(mutex);
158     auto it = container.find_as(key);
159     if (it != container.end())
160       return *it;
161   }
162 
163   // Acquire a writer-lock so that we can safely create the new instance.
164   ScopedWriterLock instanceLock(mutex, threadingIsEnabled);
165 
166   // Check for an existing instance again here, because another writer thread
167   // may have already created one. Otherwise, construct a new instance.
168   auto existing = container.insert_as(ValueT(), key);
169   if (existing.second)
170     return *existing.first = constructorFn();
171   return *existing.first;
172 }
173 
174 namespace {
175 struct AffineMapKeyInfo : DenseMapInfo<AffineMap> {
176   // Affine maps are uniqued based on their dim/symbol counts and affine
177   // expressions.
178   using KeyTy = std::tuple<unsigned, unsigned, ArrayRef<AffineExpr>>;
179   using DenseMapInfo<AffineMap>::isEqual;
180 
181   static unsigned getHashValue(const AffineMap &key) {
182     return getHashValue(
183         KeyTy(key.getNumDims(), key.getNumSymbols(), key.getResults()));
184   }
185 
186   static unsigned getHashValue(KeyTy key) {
187     return hash_combine(
188         std::get<0>(key), std::get<1>(key),
189         hash_combine_range(std::get<2>(key).begin(), std::get<2>(key).end()));
190   }
191 
192   static bool isEqual(const KeyTy &lhs, AffineMap rhs) {
193     if (rhs == getEmptyKey() || rhs == getTombstoneKey())
194       return false;
195     return lhs == std::make_tuple(rhs.getNumDims(), rhs.getNumSymbols(),
196                                   rhs.getResults());
197   }
198 };
199 
200 struct IntegerSetKeyInfo : DenseMapInfo<IntegerSet> {
201   // Integer sets are uniqued based on their dim/symbol counts, affine
202   // expressions appearing in the LHS of constraints, and eqFlags.
203   using KeyTy =
204       std::tuple<unsigned, unsigned, ArrayRef<AffineExpr>, ArrayRef<bool>>;
205   using DenseMapInfo<IntegerSet>::isEqual;
206 
207   static unsigned getHashValue(const IntegerSet &key) {
208     return getHashValue(KeyTy(key.getNumDims(), key.getNumSymbols(),
209                               key.getConstraints(), key.getEqFlags()));
210   }
211 
212   static unsigned getHashValue(KeyTy key) {
213     return hash_combine(
214         std::get<0>(key), std::get<1>(key),
215         hash_combine_range(std::get<2>(key).begin(), std::get<2>(key).end()),
216         hash_combine_range(std::get<3>(key).begin(), std::get<3>(key).end()));
217   }
218 
219   static bool isEqual(const KeyTy &lhs, IntegerSet rhs) {
220     if (rhs == getEmptyKey() || rhs == getTombstoneKey())
221       return false;
222     return lhs == std::make_tuple(rhs.getNumDims(), rhs.getNumSymbols(),
223                                   rhs.getConstraints(), rhs.getEqFlags());
224   }
225 };
226 } // end anonymous namespace.
227 
228 //===----------------------------------------------------------------------===//
229 // MLIRContextImpl
230 //===----------------------------------------------------------------------===//
231 
232 namespace mlir {
233 /// This is the implementation of the MLIRContext class, using the pImpl idiom.
234 /// This class is completely private to this file, so everything is public.
235 class MLIRContextImpl {
236 public:
237   //===--------------------------------------------------------------------===//
238   // Identifier uniquing
239   //===--------------------------------------------------------------------===//
240 
241   // Identifier allocator and mutex for thread safety.
242   llvm::BumpPtrAllocator identifierAllocator;
243   llvm::sys::SmartRWMutex<true> identifierMutex;
244 
245   //===--------------------------------------------------------------------===//
246   // Diagnostics
247   //===--------------------------------------------------------------------===//
248   DiagnosticEngine diagEngine;
249 
250   //===--------------------------------------------------------------------===//
251   // Options
252   //===--------------------------------------------------------------------===//
253 
254   /// In most cases, creating operation in unregistered dialect is not desired
255   /// and indicate a misconfiguration of the compiler. This option enables to
256   /// detect such use cases
257   bool allowUnregisteredDialects = false;
258 
259   /// Enable support for multi-threading within MLIR.
260   bool threadingIsEnabled = true;
261 
262   /// If the operation should be attached to diagnostics printed via the
263   /// Operation::emit methods.
264   bool printOpOnDiagnostic = true;
265 
266   /// If the current stack trace should be attached when emitting diagnostics.
267   bool printStackTraceOnDiagnostic = false;
268 
269   //===--------------------------------------------------------------------===//
270   // Other
271   //===--------------------------------------------------------------------===//
272 
273   /// This is a list of dialects that are created referring to this context.
274   /// The MLIRContext owns the objects.
275   std::vector<std::unique_ptr<Dialect>> dialects;
276 
277   /// This is a mapping from operation name to AbstractOperation for registered
278   /// operations.
279   llvm::StringMap<AbstractOperation> registeredOperations;
280 
281   /// These are identifiers uniqued into this MLIRContext.
282   llvm::StringSet<llvm::BumpPtrAllocator &> identifiers;
283 
284   /// An allocator used for AbstractAttribute and AbstractType objects.
285   llvm::BumpPtrAllocator abstractDialectSymbolAllocator;
286 
287   //===--------------------------------------------------------------------===//
288   // Affine uniquing
289   //===--------------------------------------------------------------------===//
290 
291   // Affine allocator and mutex for thread safety.
292   llvm::BumpPtrAllocator affineAllocator;
293   llvm::sys::SmartRWMutex<true> affineMutex;
294 
295   // Affine map uniquing.
296   using AffineMapSet = DenseSet<AffineMap, AffineMapKeyInfo>;
297   AffineMapSet affineMaps;
298 
299   // Integer set uniquing.
300   using IntegerSets = DenseSet<IntegerSet, IntegerSetKeyInfo>;
301   IntegerSets integerSets;
302 
303   // Affine expression uniquing.
304   StorageUniquer affineUniquer;
305 
306   //===--------------------------------------------------------------------===//
307   // Type uniquing
308   //===--------------------------------------------------------------------===//
309 
310   DenseMap<TypeID, const AbstractType *> registeredTypes;
311   StorageUniquer typeUniquer;
312 
313   /// Cached Type Instances.
314   FloatType bf16Ty, f16Ty, f32Ty, f64Ty;
315   IndexType indexTy;
316   IntegerType int1Ty, int8Ty, int16Ty, int32Ty, int64Ty, int128Ty;
317   NoneType noneType;
318 
319   //===--------------------------------------------------------------------===//
320   // Attribute uniquing
321   //===--------------------------------------------------------------------===//
322 
323   DenseMap<TypeID, const AbstractAttribute *> registeredAttributes;
324   StorageUniquer attributeUniquer;
325 
326   /// Cached Attribute Instances.
327   BoolAttr falseAttr, trueAttr;
328   UnitAttr unitAttr;
329   UnknownLoc unknownLocAttr;
330   DictionaryAttr emptyDictionaryAttr;
331 
332 public:
333   MLIRContextImpl() : identifiers(identifierAllocator) {}
334 };
335 } // end namespace mlir
336 
337 MLIRContext::MLIRContext() : impl(new MLIRContextImpl()) {
338   // Initialize values based on the command line flags if they were provided.
339   if (clOptions.isConstructed()) {
340     disableMultithreading(clOptions->disableThreading);
341     printOpOnDiagnostic(clOptions->printOpOnDiagnostic);
342     printStackTraceOnDiagnostic(clOptions->printStackTraceOnDiagnostic);
343   }
344 
345   // Register dialects with this context.
346   new BuiltinDialect(this);
347   registerAllDialects(this);
348 
349   // Initialize several common attributes and types to avoid the need to lock
350   // the context when accessing them.
351 
352   //// Types.
353   /// Floating-point Types.
354   impl->bf16Ty = TypeUniquer::get<FloatType>(this, StandardTypes::BF16);
355   impl->f16Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F16);
356   impl->f32Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F32);
357   impl->f64Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F64);
358   /// Index Type.
359   impl->indexTy = TypeUniquer::get<IndexType>(this, StandardTypes::Index);
360   /// Integer Types.
361   impl->int1Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer, 1,
362                                                IntegerType::Signless);
363   impl->int8Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer, 8,
364                                                IntegerType::Signless);
365   impl->int16Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
366                                                 16, IntegerType::Signless);
367   impl->int32Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
368                                                 32, IntegerType::Signless);
369   impl->int64Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
370                                                 64, IntegerType::Signless);
371   impl->int128Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
372                                                  128, IntegerType::Signless);
373   /// None Type.
374   impl->noneType = TypeUniquer::get<NoneType>(this, StandardTypes::None);
375 
376   //// Attributes.
377   //// Note: These must be registered after the types as they may generate one
378   //// of the above types internally.
379   /// Bool Attributes.
380   impl->falseAttr = AttributeUniquer::get<IntegerAttr>(
381                         this, StandardAttributes::Integer, impl->int1Ty,
382                         APInt(/*numBits=*/1, false))
383                         .cast<BoolAttr>();
384   impl->trueAttr = AttributeUniquer::get<IntegerAttr>(
385                        this, StandardAttributes::Integer, impl->int1Ty,
386                        APInt(/*numBits=*/1, true))
387                        .cast<BoolAttr>();
388   /// Unit Attribute.
389   impl->unitAttr =
390       AttributeUniquer::get<UnitAttr>(this, StandardAttributes::Unit);
391   /// Unknown Location Attribute.
392   impl->unknownLocAttr = AttributeUniquer::get<UnknownLoc>(
393       this, StandardAttributes::UnknownLocation);
394   /// The empty dictionary attribute.
395   impl->emptyDictionaryAttr = AttributeUniquer::get<DictionaryAttr>(
396       this, StandardAttributes::Dictionary, ArrayRef<NamedAttribute>());
397 }
398 
399 MLIRContext::~MLIRContext() {}
400 
401 /// Copy the specified array of elements into memory managed by the provided
402 /// bump pointer allocator.  This assumes the elements are all PODs.
403 template <typename T>
404 static ArrayRef<T> copyArrayRefInto(llvm::BumpPtrAllocator &allocator,
405                                     ArrayRef<T> elements) {
406   auto result = allocator.Allocate<T>(elements.size());
407   std::uninitialized_copy(elements.begin(), elements.end(), result);
408   return ArrayRef<T>(result, elements.size());
409 }
410 
411 //===----------------------------------------------------------------------===//
412 // Diagnostic Handlers
413 //===----------------------------------------------------------------------===//
414 
415 /// Returns the diagnostic engine for this context.
416 DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
417 
418 //===----------------------------------------------------------------------===//
419 // Dialect and Operation Registration
420 //===----------------------------------------------------------------------===//
421 
422 /// Return information about all registered IR dialects.
423 std::vector<Dialect *> MLIRContext::getRegisteredDialects() {
424   std::vector<Dialect *> result;
425   result.reserve(impl->dialects.size());
426   for (auto &dialect : impl->dialects)
427     result.push_back(dialect.get());
428   return result;
429 }
430 
431 /// Get a registered IR dialect with the given namespace. If none is found,
432 /// then return nullptr.
433 Dialect *MLIRContext::getRegisteredDialect(StringRef name) {
434   // Dialects are sorted by name, so we can use binary search for lookup.
435   auto it = llvm::lower_bound(
436       impl->dialects, name,
437       [](const auto &lhs, StringRef rhs) { return lhs->getNamespace() < rhs; });
438   return (it != impl->dialects.end() && (*it)->getNamespace() == name)
439              ? (*it).get()
440              : nullptr;
441 }
442 
443 /// Register this dialect object with the specified context.  The context
444 /// takes ownership of the heap allocated dialect.
445 void Dialect::registerDialect(MLIRContext *context) {
446   auto &impl = context->getImpl();
447   std::unique_ptr<Dialect> dialect(this);
448 
449   // Get the correct insertion position sorted by namespace.
450   auto insertPt = llvm::lower_bound(
451       impl.dialects, dialect, [](const auto &lhs, const auto &rhs) {
452         return lhs->getNamespace() < rhs->getNamespace();
453       });
454 
455   // Abort if dialect with namespace has already been registered.
456   if (insertPt != impl.dialects.end() &&
457       (*insertPt)->getNamespace() == getNamespace()) {
458     llvm::report_fatal_error("a dialect with namespace '" + getNamespace() +
459                              "' has already been registered");
460   }
461   impl.dialects.insert(insertPt, std::move(dialect));
462 }
463 
464 bool MLIRContext::allowsUnregisteredDialects() {
465   return impl->allowUnregisteredDialects;
466 }
467 
468 void MLIRContext::allowUnregisteredDialects(bool allowing) {
469   impl->allowUnregisteredDialects = allowing;
470 }
471 
472 /// Return true if multi-threading is disabled by the context.
473 bool MLIRContext::isMultithreadingEnabled() {
474   return impl->threadingIsEnabled && llvm::llvm_is_multithreaded();
475 }
476 
477 /// Set the flag specifying if multi-threading is disabled by the context.
478 void MLIRContext::disableMultithreading(bool disable) {
479   impl->threadingIsEnabled = !disable;
480 
481   // Update the threading mode for each of the uniquers.
482   impl->affineUniquer.disableMultithreading(disable);
483   impl->attributeUniquer.disableMultithreading(disable);
484   impl->typeUniquer.disableMultithreading(disable);
485 }
486 
487 /// Return true if we should attach the operation to diagnostics emitted via
488 /// Operation::emit.
489 bool MLIRContext::shouldPrintOpOnDiagnostic() {
490   return impl->printOpOnDiagnostic;
491 }
492 
493 /// Set the flag specifying if we should attach the operation to diagnostics
494 /// emitted via Operation::emit.
495 void MLIRContext::printOpOnDiagnostic(bool enable) {
496   impl->printOpOnDiagnostic = enable;
497 }
498 
499 /// Return true if we should attach the current stacktrace to diagnostics when
500 /// emitted.
501 bool MLIRContext::shouldPrintStackTraceOnDiagnostic() {
502   return impl->printStackTraceOnDiagnostic;
503 }
504 
505 /// Set the flag specifying if we should attach the current stacktrace when
506 /// emitting diagnostics.
507 void MLIRContext::printStackTraceOnDiagnostic(bool enable) {
508   impl->printStackTraceOnDiagnostic = enable;
509 }
510 
511 /// Return information about all registered operations.  This isn't very
512 /// efficient, typically you should ask the operations about their properties
513 /// directly.
514 std::vector<AbstractOperation *> MLIRContext::getRegisteredOperations() {
515   // We just have the operations in a non-deterministic hash table order. Dump
516   // into a temporary array, then sort it by operation name to get a stable
517   // ordering.
518   llvm::StringMap<AbstractOperation> &registeredOps =
519       impl->registeredOperations;
520 
521   std::vector<AbstractOperation *> result;
522   result.reserve(registeredOps.size());
523   for (auto &elt : registeredOps)
524     result.push_back(&elt.second);
525   llvm::array_pod_sort(
526       result.begin(), result.end(),
527       [](AbstractOperation *const *lhs, AbstractOperation *const *rhs) {
528         return (*lhs)->name.compare((*rhs)->name);
529       });
530 
531   return result;
532 }
533 
534 bool MLIRContext::isOperationRegistered(StringRef name) {
535   return impl->registeredOperations.count(name);
536 }
537 
538 void Dialect::addOperation(AbstractOperation opInfo) {
539   assert((getNamespace().empty() || opInfo.dialect.name == getNamespace()) &&
540          "op name doesn't start with dialect namespace");
541   assert(&opInfo.dialect == this && "Dialect object mismatch");
542   auto &impl = context->getImpl();
543   StringRef opName = opInfo.name;
544   if (!impl.registeredOperations.insert({opName, std::move(opInfo)}).second) {
545     llvm::errs() << "error: operation named '" << opInfo.name
546                  << "' is already registered.\n";
547     abort();
548   }
549 }
550 
551 void Dialect::addType(TypeID typeID, AbstractType &&typeInfo) {
552   auto &impl = context->getImpl();
553   auto *newInfo =
554       new (impl.abstractDialectSymbolAllocator.Allocate<AbstractType>())
555           AbstractType(std::move(typeInfo));
556   if (!impl.registeredTypes.insert({typeID, newInfo}).second)
557     llvm::report_fatal_error("Dialect Type already registered.");
558 }
559 
560 void Dialect::addAttribute(TypeID typeID, AbstractAttribute &&attrInfo) {
561   auto &impl = context->getImpl();
562   auto *newInfo =
563       new (impl.abstractDialectSymbolAllocator.Allocate<AbstractAttribute>())
564           AbstractAttribute(std::move(attrInfo));
565   if (!impl.registeredAttributes.insert({typeID, newInfo}).second)
566     llvm::report_fatal_error("Dialect Attribute already registered.");
567 }
568 
569 /// Get the dialect that registered the attribute with the provided typeid.
570 const AbstractAttribute &AbstractAttribute::lookup(TypeID typeID,
571                                                    MLIRContext *context) {
572   auto &impl = context->getImpl();
573   auto it = impl.registeredAttributes.find(typeID);
574   if (it == impl.registeredAttributes.end())
575     llvm::report_fatal_error("Trying to create an Attribute that was not "
576                              "registered in this MLIRContext.");
577   return *it->second;
578 }
579 
580 /// Look up the specified operation in the operation set and return a pointer
581 /// to it if present.  Otherwise, return a null pointer.
582 const AbstractOperation *AbstractOperation::lookup(StringRef opName,
583                                                    MLIRContext *context) {
584   auto &impl = context->getImpl();
585   auto it = impl.registeredOperations.find(opName);
586   if (it != impl.registeredOperations.end())
587     return &it->second;
588   return nullptr;
589 }
590 
591 /// Get the dialect that registered the type with the provided typeid.
592 const AbstractType &AbstractType::lookup(TypeID typeID, MLIRContext *context) {
593   auto &impl = context->getImpl();
594   auto it = impl.registeredTypes.find(typeID);
595   if (it == impl.registeredTypes.end())
596     llvm::report_fatal_error(
597         "Trying to create a Type that was not registered in this MLIRContext.");
598   return *it->second;
599 }
600 
601 //===----------------------------------------------------------------------===//
602 // Identifier uniquing
603 //===----------------------------------------------------------------------===//
604 
605 /// Return an identifier for the specified string.
606 Identifier Identifier::get(StringRef str, MLIRContext *context) {
607   auto &impl = context->getImpl();
608 
609   // Check for an existing identifier in read-only mode.
610   if (context->isMultithreadingEnabled()) {
611     llvm::sys::SmartScopedReader<true> contextLock(impl.identifierMutex);
612     auto it = impl.identifiers.find(str);
613     if (it != impl.identifiers.end())
614       return Identifier(&*it);
615   }
616 
617   // Check invariants after seeing if we already have something in the
618   // identifier table - if we already had it in the table, then it already
619   // passed invariant checks.
620   assert(!str.empty() && "Cannot create an empty identifier");
621   assert(str.find('\0') == StringRef::npos &&
622          "Cannot create an identifier with a nul character");
623 
624   // Acquire a writer-lock so that we can safely create the new instance.
625   ScopedWriterLock contextLock(impl.identifierMutex, impl.threadingIsEnabled);
626   auto it = impl.identifiers.insert(str).first;
627   return Identifier(&*it);
628 }
629 
630 //===----------------------------------------------------------------------===//
631 // Type uniquing
632 //===----------------------------------------------------------------------===//
633 
634 /// Returns the storage uniquer used for constructing type storage instances.
635 /// This should not be used directly.
636 StorageUniquer &MLIRContext::getTypeUniquer() { return getImpl().typeUniquer; }
637 
638 FloatType FloatType::get(StandardTypes::Kind kind, MLIRContext *context) {
639   assert(kindof(kind) && "Not a FP kind.");
640   switch (kind) {
641   case StandardTypes::BF16:
642     return context->getImpl().bf16Ty;
643   case StandardTypes::F16:
644     return context->getImpl().f16Ty;
645   case StandardTypes::F32:
646     return context->getImpl().f32Ty;
647   case StandardTypes::F64:
648     return context->getImpl().f64Ty;
649   default:
650     llvm_unreachable("unexpected floating-point kind");
651   }
652 }
653 
654 /// Get an instance of the IndexType.
655 IndexType IndexType::get(MLIRContext *context) {
656   return context->getImpl().indexTy;
657 }
658 
659 /// Return an existing integer type instance if one is cached within the
660 /// context.
661 static IntegerType
662 getCachedIntegerType(unsigned width,
663                      IntegerType::SignednessSemantics signedness,
664                      MLIRContext *context) {
665   if (signedness != IntegerType::Signless)
666     return IntegerType();
667 
668   switch (width) {
669   case 1:
670     return context->getImpl().int1Ty;
671   case 8:
672     return context->getImpl().int8Ty;
673   case 16:
674     return context->getImpl().int16Ty;
675   case 32:
676     return context->getImpl().int32Ty;
677   case 64:
678     return context->getImpl().int64Ty;
679   case 128:
680     return context->getImpl().int128Ty;
681   default:
682     return IntegerType();
683   }
684 }
685 
686 IntegerType IntegerType::get(unsigned width, MLIRContext *context) {
687   return get(width, IntegerType::Signless, context);
688 }
689 
690 IntegerType IntegerType::get(unsigned width,
691                              IntegerType::SignednessSemantics signedness,
692                              MLIRContext *context) {
693   if (auto cached = getCachedIntegerType(width, signedness, context))
694     return cached;
695   return Base::get(context, StandardTypes::Integer, width, signedness);
696 }
697 
698 IntegerType IntegerType::getChecked(unsigned width, Location location) {
699   return getChecked(width, IntegerType::Signless, location);
700 }
701 
702 IntegerType IntegerType::getChecked(unsigned width,
703                                     SignednessSemantics signedness,
704                                     Location location) {
705   if (auto cached =
706           getCachedIntegerType(width, signedness, location->getContext()))
707     return cached;
708   return Base::getChecked(location, StandardTypes::Integer, width, signedness);
709 }
710 
711 /// Get an instance of the NoneType.
712 NoneType NoneType::get(MLIRContext *context) {
713   return context->getImpl().noneType;
714 }
715 
716 //===----------------------------------------------------------------------===//
717 // Attribute uniquing
718 //===----------------------------------------------------------------------===//
719 
720 /// Returns the storage uniquer used for constructing attribute storage
721 /// instances. This should not be used directly.
722 StorageUniquer &MLIRContext::getAttributeUniquer() {
723   return getImpl().attributeUniquer;
724 }
725 
726 /// Initialize the given attribute storage instance.
727 void AttributeUniquer::initializeAttributeStorage(AttributeStorage *storage,
728                                                   MLIRContext *ctx,
729                                                   TypeID attrID) {
730   storage->initialize(AbstractAttribute::lookup(attrID, ctx));
731 
732   // If the attribute did not provide a type, then default to NoneType.
733   if (!storage->getType())
734     storage->setType(NoneType::get(ctx));
735 }
736 
737 BoolAttr BoolAttr::get(bool value, MLIRContext *context) {
738   return value ? context->getImpl().trueAttr : context->getImpl().falseAttr;
739 }
740 
741 UnitAttr UnitAttr::get(MLIRContext *context) {
742   return context->getImpl().unitAttr;
743 }
744 
745 Location UnknownLoc::get(MLIRContext *context) {
746   return context->getImpl().unknownLocAttr;
747 }
748 
749 /// Return empty dictionary.
750 DictionaryAttr DictionaryAttr::getEmpty(MLIRContext *context) {
751   return context->getImpl().emptyDictionaryAttr;
752 }
753 
754 //===----------------------------------------------------------------------===//
755 // AffineMap uniquing
756 //===----------------------------------------------------------------------===//
757 
758 StorageUniquer &MLIRContext::getAffineUniquer() {
759   return getImpl().affineUniquer;
760 }
761 
762 AffineMap AffineMap::getImpl(unsigned dimCount, unsigned symbolCount,
763                              ArrayRef<AffineExpr> results,
764                              MLIRContext *context) {
765   auto &impl = context->getImpl();
766   auto key = std::make_tuple(dimCount, symbolCount, results);
767 
768   // Safely get or create an AffineMap instance.
769   return safeGetOrCreate(
770       impl.affineMaps, key, impl.affineMutex, impl.threadingIsEnabled, [&] {
771         auto *res = impl.affineAllocator.Allocate<detail::AffineMapStorage>();
772 
773         // Copy the results into the bump pointer.
774         results = copyArrayRefInto(impl.affineAllocator, results);
775 
776         // Initialize the memory using placement new.
777         new (res)
778             detail::AffineMapStorage{dimCount, symbolCount, results, context};
779         return AffineMap(res);
780       });
781 }
782 
783 AffineMap AffineMap::get(MLIRContext *context) {
784   return getImpl(/*dimCount=*/0, /*symbolCount=*/0, /*results=*/{}, context);
785 }
786 
787 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
788                          MLIRContext *context) {
789   return getImpl(dimCount, symbolCount, /*results=*/{}, context);
790 }
791 
792 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
793                          AffineExpr result) {
794   return getImpl(dimCount, symbolCount, {result}, result.getContext());
795 }
796 
797 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
798                          ArrayRef<AffineExpr> results, MLIRContext *context) {
799   return getImpl(dimCount, symbolCount, results, context);
800 }
801 
802 //===----------------------------------------------------------------------===//
803 // Integer Sets: these are allocated into the bump pointer, and are immutable.
804 // Unlike AffineMap's, these are uniqued only if they are small.
805 //===----------------------------------------------------------------------===//
806 
807 IntegerSet IntegerSet::get(unsigned dimCount, unsigned symbolCount,
808                            ArrayRef<AffineExpr> constraints,
809                            ArrayRef<bool> eqFlags) {
810   // The number of constraints can't be zero.
811   assert(!constraints.empty());
812   assert(constraints.size() == eqFlags.size());
813 
814   auto &impl = constraints[0].getContext()->getImpl();
815 
816   // A utility function to construct a new IntegerSetStorage instance.
817   auto constructorFn = [&] {
818     auto *res = impl.affineAllocator.Allocate<detail::IntegerSetStorage>();
819 
820     // Copy the results and equality flags into the bump pointer.
821     constraints = copyArrayRefInto(impl.affineAllocator, constraints);
822     eqFlags = copyArrayRefInto(impl.affineAllocator, eqFlags);
823 
824     // Initialize the memory using placement new.
825     new (res)
826         detail::IntegerSetStorage{dimCount, symbolCount, constraints, eqFlags};
827     return IntegerSet(res);
828   };
829 
830   // If this instance is uniqued, then we handle it separately so that multiple
831   // threads may simultaneously access existing instances.
832   if (constraints.size() < IntegerSet::kUniquingThreshold) {
833     auto key = std::make_tuple(dimCount, symbolCount, constraints, eqFlags);
834     return safeGetOrCreate(impl.integerSets, key, impl.affineMutex,
835                            impl.threadingIsEnabled, constructorFn);
836   }
837 
838   // Otherwise, acquire a writer-lock so that we can safely create the new
839   // instance.
840   ScopedWriterLock affineLock(impl.affineMutex, impl.threadingIsEnabled);
841   return constructorFn();
842 }
843 
844 //===----------------------------------------------------------------------===//
845 // StorageUniquerSupport
846 //===----------------------------------------------------------------------===//
847 
848 /// Utility method to generate a default location for use when checking the
849 /// construction invariants of a storage object. This is defined out-of-line to
850 /// avoid the need to include Location.h.
851 const AttributeStorage *
852 mlir::detail::generateUnknownStorageLocation(MLIRContext *ctx) {
853   return reinterpret_cast<const AttributeStorage *>(
854       ctx->getImpl().unknownLocAttr.getAsOpaquePointer());
855 }
856