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   /// A general purpose mutex to lock access to parts of the context that do not
274   /// have a more specific mutex, e.g. registry operations.
275   llvm::sys::SmartRWMutex<true> contextMutex;
276 
277   /// This is a list of dialects that are created referring to this context.
278   /// The MLIRContext owns the objects.
279   std::vector<std::unique_ptr<Dialect>> dialects;
280 
281   /// This is a mapping from operation name to AbstractOperation for registered
282   /// operations.
283   llvm::StringMap<AbstractOperation> registeredOperations;
284 
285   /// This is a mapping from type id to Dialect for registered attributes and
286   /// types.
287   DenseMap<TypeID, Dialect *> registeredDialectSymbols;
288 
289   /// These are identifiers uniqued into this MLIRContext.
290   llvm::StringSet<llvm::BumpPtrAllocator &> identifiers;
291 
292   //===--------------------------------------------------------------------===//
293   // Affine uniquing
294   //===--------------------------------------------------------------------===//
295 
296   // Affine allocator and mutex for thread safety.
297   llvm::BumpPtrAllocator affineAllocator;
298   llvm::sys::SmartRWMutex<true> affineMutex;
299 
300   // Affine map uniquing.
301   using AffineMapSet = DenseSet<AffineMap, AffineMapKeyInfo>;
302   AffineMapSet affineMaps;
303 
304   // Integer set uniquing.
305   using IntegerSets = DenseSet<IntegerSet, IntegerSetKeyInfo>;
306   IntegerSets integerSets;
307 
308   // Affine expression uniquing.
309   StorageUniquer affineUniquer;
310 
311   //===--------------------------------------------------------------------===//
312   // Type uniquing
313   //===--------------------------------------------------------------------===//
314   StorageUniquer typeUniquer;
315 
316   /// Cached Type Instances.
317   FloatType bf16Ty, f16Ty, f32Ty, f64Ty;
318   IndexType indexTy;
319   IntegerType int1Ty, int8Ty, int16Ty, int32Ty, int64Ty, int128Ty;
320   NoneType noneType;
321 
322   //===--------------------------------------------------------------------===//
323   // Attribute uniquing
324   //===--------------------------------------------------------------------===//
325   StorageUniquer attributeUniquer;
326 
327   /// Cached Attribute Instances.
328   BoolAttr falseAttr, trueAttr;
329   UnitAttr unitAttr;
330   UnknownLoc unknownLocAttr;
331   DictionaryAttr emptyDictionaryAttr;
332 
333 public:
334   MLIRContextImpl() : identifiers(identifierAllocator) {}
335 };
336 } // end namespace mlir
337 
338 MLIRContext::MLIRContext() : impl(new MLIRContextImpl()) {
339   // Initialize values based on the command line flags if they were provided.
340   if (clOptions.isConstructed()) {
341     disableMultithreading(clOptions->disableThreading);
342     printOpOnDiagnostic(clOptions->printOpOnDiagnostic);
343     printStackTraceOnDiagnostic(clOptions->printStackTraceOnDiagnostic);
344   }
345 
346   // Register dialects with this context.
347   new BuiltinDialect(this);
348   registerAllDialects(this);
349 
350   // Initialize several common attributes and types to avoid the need to lock
351   // the context when accessing them.
352 
353   //// Types.
354   /// Floating-point Types.
355   impl->bf16Ty = TypeUniquer::get<FloatType>(this, StandardTypes::BF16);
356   impl->f16Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F16);
357   impl->f32Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F32);
358   impl->f64Ty = TypeUniquer::get<FloatType>(this, StandardTypes::F64);
359   /// Index Type.
360   impl->indexTy = TypeUniquer::get<IndexType>(this, StandardTypes::Index);
361   /// Integer Types.
362   impl->int1Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer, 1,
363                                                IntegerType::Signless);
364   impl->int8Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer, 8,
365                                                IntegerType::Signless);
366   impl->int16Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
367                                                 16, IntegerType::Signless);
368   impl->int32Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
369                                                 32, IntegerType::Signless);
370   impl->int64Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
371                                                 64, IntegerType::Signless);
372   impl->int128Ty = TypeUniquer::get<IntegerType>(this, StandardTypes::Integer,
373                                                  128, IntegerType::Signless);
374   /// None Type.
375   impl->noneType = TypeUniquer::get<NoneType>(this, StandardTypes::None);
376 
377   //// Attributes.
378   //// Note: These must be registered after the types as they may generate one
379   //// of the above types internally.
380   /// Bool Attributes.
381   impl->falseAttr = AttributeUniquer::get<IntegerAttr>(
382                         this, StandardAttributes::Integer, impl->int1Ty,
383                         APInt(/*numBits=*/1, false))
384                         .cast<BoolAttr>();
385   impl->trueAttr = AttributeUniquer::get<IntegerAttr>(
386                        this, StandardAttributes::Integer, impl->int1Ty,
387                        APInt(/*numBits=*/1, true))
388                        .cast<BoolAttr>();
389   /// Unit Attribute.
390   impl->unitAttr =
391       AttributeUniquer::get<UnitAttr>(this, StandardAttributes::Unit);
392   /// Unknown Location Attribute.
393   impl->unknownLocAttr = AttributeUniquer::get<UnknownLoc>(
394       this, StandardAttributes::UnknownLocation);
395   /// The empty dictionary attribute.
396   impl->emptyDictionaryAttr = AttributeUniquer::get<DictionaryAttr>(
397       this, StandardAttributes::Dictionary, ArrayRef<NamedAttribute>());
398 }
399 
400 MLIRContext::~MLIRContext() {}
401 
402 /// Copy the specified array of elements into memory managed by the provided
403 /// bump pointer allocator.  This assumes the elements are all PODs.
404 template <typename T>
405 static ArrayRef<T> copyArrayRefInto(llvm::BumpPtrAllocator &allocator,
406                                     ArrayRef<T> elements) {
407   auto result = allocator.Allocate<T>(elements.size());
408   std::uninitialized_copy(elements.begin(), elements.end(), result);
409   return ArrayRef<T>(result, elements.size());
410 }
411 
412 //===----------------------------------------------------------------------===//
413 // Diagnostic Handlers
414 //===----------------------------------------------------------------------===//
415 
416 /// Returns the diagnostic engine for this context.
417 DiagnosticEngine &MLIRContext::getDiagEngine() { return getImpl().diagEngine; }
418 
419 //===----------------------------------------------------------------------===//
420 // Dialect and Operation Registration
421 //===----------------------------------------------------------------------===//
422 
423 /// Return information about all registered IR dialects.
424 std::vector<Dialect *> MLIRContext::getRegisteredDialects() {
425   // Lock access to the context registry.
426   ScopedReaderLock registryLock(impl->contextMutex, impl->threadingIsEnabled);
427   std::vector<Dialect *> result;
428   result.reserve(impl->dialects.size());
429   for (auto &dialect : impl->dialects)
430     result.push_back(dialect.get());
431   return result;
432 }
433 
434 /// Get a registered IR dialect with the given namespace. If none is found,
435 /// then return nullptr.
436 Dialect *MLIRContext::getRegisteredDialect(StringRef name) {
437   // Lock access to the context registry.
438   ScopedReaderLock registryLock(impl->contextMutex, impl->threadingIsEnabled);
439 
440   // Dialects are sorted by name, so we can use binary search for lookup.
441   auto it = llvm::lower_bound(
442       impl->dialects, name,
443       [](const auto &lhs, StringRef rhs) { return lhs->getNamespace() < rhs; });
444   return (it != impl->dialects.end() && (*it)->getNamespace() == name)
445              ? (*it).get()
446              : nullptr;
447 }
448 
449 /// Register this dialect object with the specified context.  The context
450 /// takes ownership of the heap allocated dialect.
451 void Dialect::registerDialect(MLIRContext *context) {
452   auto &impl = context->getImpl();
453   std::unique_ptr<Dialect> dialect(this);
454 
455   // Lock access to the context registry.
456   ScopedWriterLock registryLock(impl.contextMutex, impl.threadingIsEnabled);
457 
458   // Get the correct insertion position sorted by namespace.
459   auto insertPt = llvm::lower_bound(
460       impl.dialects, dialect, [](const auto &lhs, const auto &rhs) {
461         return lhs->getNamespace() < rhs->getNamespace();
462       });
463 
464   // Abort if dialect with namespace has already been registered.
465   if (insertPt != impl.dialects.end() &&
466       (*insertPt)->getNamespace() == getNamespace()) {
467     llvm::report_fatal_error("a dialect with namespace '" + getNamespace() +
468                              "' has already been registered");
469   }
470   impl.dialects.insert(insertPt, std::move(dialect));
471 }
472 
473 bool MLIRContext::allowsUnregisteredDialects() {
474   return impl->allowUnregisteredDialects;
475 }
476 
477 void MLIRContext::allowUnregisteredDialects(bool allowing) {
478   impl->allowUnregisteredDialects = allowing;
479 }
480 
481 /// Return true if multi-threading is disabled by the context.
482 bool MLIRContext::isMultithreadingEnabled() {
483   return impl->threadingIsEnabled && llvm::llvm_is_multithreaded();
484 }
485 
486 /// Set the flag specifying if multi-threading is disabled by the context.
487 void MLIRContext::disableMultithreading(bool disable) {
488   impl->threadingIsEnabled = !disable;
489 
490   // Update the threading mode for each of the uniquers.
491   impl->affineUniquer.disableMultithreading(disable);
492   impl->attributeUniquer.disableMultithreading(disable);
493   impl->typeUniquer.disableMultithreading(disable);
494 }
495 
496 /// Return true if we should attach the operation to diagnostics emitted via
497 /// Operation::emit.
498 bool MLIRContext::shouldPrintOpOnDiagnostic() {
499   return impl->printOpOnDiagnostic;
500 }
501 
502 /// Set the flag specifying if we should attach the operation to diagnostics
503 /// emitted via Operation::emit.
504 void MLIRContext::printOpOnDiagnostic(bool enable) {
505   impl->printOpOnDiagnostic = enable;
506 }
507 
508 /// Return true if we should attach the current stacktrace to diagnostics when
509 /// emitted.
510 bool MLIRContext::shouldPrintStackTraceOnDiagnostic() {
511   return impl->printStackTraceOnDiagnostic;
512 }
513 
514 /// Set the flag specifying if we should attach the current stacktrace when
515 /// emitting diagnostics.
516 void MLIRContext::printStackTraceOnDiagnostic(bool enable) {
517   impl->printStackTraceOnDiagnostic = enable;
518 }
519 
520 /// Return information about all registered operations.  This isn't very
521 /// efficient, typically you should ask the operations about their properties
522 /// directly.
523 std::vector<AbstractOperation *> MLIRContext::getRegisteredOperations() {
524   std::vector<std::pair<StringRef, AbstractOperation *>> opsToSort;
525 
526   { // Lock access to the context registry.
527     ScopedReaderLock registryLock(impl->contextMutex, impl->threadingIsEnabled);
528 
529     // We just have the operations in a non-deterministic hash table order. Dump
530     // into a temporary array, then sort it by operation name to get a stable
531     // ordering.
532     llvm::StringMap<AbstractOperation> &registeredOps =
533         impl->registeredOperations;
534 
535     opsToSort.reserve(registeredOps.size());
536     for (auto &elt : registeredOps)
537       opsToSort.push_back({elt.first(), &elt.second});
538   }
539 
540   llvm::array_pod_sort(opsToSort.begin(), opsToSort.end());
541 
542   std::vector<AbstractOperation *> result;
543   result.reserve(opsToSort.size());
544   for (auto &elt : opsToSort)
545     result.push_back(elt.second);
546   return result;
547 }
548 
549 bool MLIRContext::isOperationRegistered(StringRef name) {
550   // Lock access to the context registry.
551   ScopedReaderLock registryLock(impl->contextMutex, impl->threadingIsEnabled);
552 
553   return impl->registeredOperations.count(name);
554 }
555 
556 void Dialect::addOperation(AbstractOperation opInfo) {
557   assert((getNamespace().empty() || opInfo.dialect.name == getNamespace()) &&
558          "op name doesn't start with dialect namespace");
559   assert(&opInfo.dialect == this && "Dialect object mismatch");
560   auto &impl = context->getImpl();
561 
562   // Lock access to the context registry.
563   ScopedWriterLock registryLock(impl.contextMutex, impl.threadingIsEnabled);
564   if (!impl.registeredOperations.insert({opInfo.name, opInfo}).second) {
565     llvm::errs() << "error: operation named '" << opInfo.name
566                  << "' is already registered.\n";
567     abort();
568   }
569 }
570 
571 /// Register a dialect-specific symbol(e.g. type) with the current context.
572 void Dialect::addSymbol(TypeID typeID) {
573   auto &impl = context->getImpl();
574 
575   // Lock access to the context registry.
576   ScopedWriterLock registryLock(impl.contextMutex, impl.threadingIsEnabled);
577   if (!impl.registeredDialectSymbols.insert({typeID, this}).second) {
578     llvm::errs() << "error: dialect symbol already registered.\n";
579     abort();
580   }
581 }
582 
583 /// Look up the specified operation in the operation set and return a pointer
584 /// to it if present.  Otherwise, return a null pointer.
585 const AbstractOperation *AbstractOperation::lookup(StringRef opName,
586                                                    MLIRContext *context) {
587   auto &impl = context->getImpl();
588 
589   // Lock access to the context registry.
590   ScopedReaderLock registryLock(impl.contextMutex, impl.threadingIsEnabled);
591   auto it = impl.registeredOperations.find(opName);
592   if (it != impl.registeredOperations.end())
593     return &it->second;
594   return nullptr;
595 }
596 
597 //===----------------------------------------------------------------------===//
598 // Identifier uniquing
599 //===----------------------------------------------------------------------===//
600 
601 /// Return an identifier for the specified string.
602 Identifier Identifier::get(StringRef str, MLIRContext *context) {
603   auto &impl = context->getImpl();
604 
605   // Check for an existing identifier in read-only mode.
606   if (context->isMultithreadingEnabled()) {
607     llvm::sys::SmartScopedReader<true> contextLock(impl.identifierMutex);
608     auto it = impl.identifiers.find(str);
609     if (it != impl.identifiers.end())
610       return Identifier(&*it);
611   }
612 
613   // Check invariants after seeing if we already have something in the
614   // identifier table - if we already had it in the table, then it already
615   // passed invariant checks.
616   assert(!str.empty() && "Cannot create an empty identifier");
617   assert(str.find('\0') == StringRef::npos &&
618          "Cannot create an identifier with a nul character");
619 
620   // Acquire a writer-lock so that we can safely create the new instance.
621   ScopedWriterLock contextLock(impl.identifierMutex, impl.threadingIsEnabled);
622   auto it = impl.identifiers.insert(str).first;
623   return Identifier(&*it);
624 }
625 
626 //===----------------------------------------------------------------------===//
627 // Type uniquing
628 //===----------------------------------------------------------------------===//
629 
630 static Dialect &lookupDialectForSymbol(MLIRContext *ctx, TypeID typeID) {
631   auto &impl = ctx->getImpl();
632   auto it = impl.registeredDialectSymbols.find(typeID);
633   if (it == impl.registeredDialectSymbols.end())
634     llvm::report_fatal_error(
635         "Trying to create a type that was not registered in this MLIRContext.");
636   return *it->second;
637 }
638 
639 /// Returns the storage uniquer used for constructing type storage instances.
640 /// This should not be used directly.
641 StorageUniquer &MLIRContext::getTypeUniquer() { return getImpl().typeUniquer; }
642 
643 /// Get the dialect that registered the type with the provided typeid.
644 Dialect &TypeUniquer::lookupDialectForType(MLIRContext *ctx, TypeID typeID) {
645   return lookupDialectForSymbol(ctx, typeID);
646 }
647 
648 FloatType FloatType::get(StandardTypes::Kind kind, MLIRContext *context) {
649   assert(kindof(kind) && "Not a FP kind.");
650   switch (kind) {
651   case StandardTypes::BF16:
652     return context->getImpl().bf16Ty;
653   case StandardTypes::F16:
654     return context->getImpl().f16Ty;
655   case StandardTypes::F32:
656     return context->getImpl().f32Ty;
657   case StandardTypes::F64:
658     return context->getImpl().f64Ty;
659   default:
660     llvm_unreachable("unexpected floating-point kind");
661   }
662 }
663 
664 /// Get an instance of the IndexType.
665 IndexType IndexType::get(MLIRContext *context) {
666   return context->getImpl().indexTy;
667 }
668 
669 /// Return an existing integer type instance if one is cached within the
670 /// context.
671 static IntegerType
672 getCachedIntegerType(unsigned width,
673                      IntegerType::SignednessSemantics signedness,
674                      MLIRContext *context) {
675   if (signedness != IntegerType::Signless)
676     return IntegerType();
677 
678   switch (width) {
679   case 1:
680     return context->getImpl().int1Ty;
681   case 8:
682     return context->getImpl().int8Ty;
683   case 16:
684     return context->getImpl().int16Ty;
685   case 32:
686     return context->getImpl().int32Ty;
687   case 64:
688     return context->getImpl().int64Ty;
689   case 128:
690     return context->getImpl().int128Ty;
691   default:
692     return IntegerType();
693   }
694 }
695 
696 IntegerType IntegerType::get(unsigned width, MLIRContext *context) {
697   return get(width, IntegerType::Signless, context);
698 }
699 
700 IntegerType IntegerType::get(unsigned width,
701                              IntegerType::SignednessSemantics signedness,
702                              MLIRContext *context) {
703   if (auto cached = getCachedIntegerType(width, signedness, context))
704     return cached;
705   return Base::get(context, StandardTypes::Integer, width, signedness);
706 }
707 
708 IntegerType IntegerType::getChecked(unsigned width, Location location) {
709   return getChecked(width, IntegerType::Signless, location);
710 }
711 
712 IntegerType IntegerType::getChecked(unsigned width,
713                                     SignednessSemantics signedness,
714                                     Location location) {
715   if (auto cached =
716           getCachedIntegerType(width, signedness, location->getContext()))
717     return cached;
718   return Base::getChecked(location, StandardTypes::Integer, width, signedness);
719 }
720 
721 /// Get an instance of the NoneType.
722 NoneType NoneType::get(MLIRContext *context) {
723   return context->getImpl().noneType;
724 }
725 
726 //===----------------------------------------------------------------------===//
727 // Attribute uniquing
728 //===----------------------------------------------------------------------===//
729 
730 /// Returns the storage uniquer used for constructing attribute storage
731 /// instances. This should not be used directly.
732 StorageUniquer &MLIRContext::getAttributeUniquer() {
733   return getImpl().attributeUniquer;
734 }
735 
736 /// Initialize the given attribute storage instance.
737 void AttributeUniquer::initializeAttributeStorage(AttributeStorage *storage,
738                                                   MLIRContext *ctx,
739                                                   TypeID attrID) {
740   storage->initializeDialect(lookupDialectForSymbol(ctx, attrID));
741 
742   // If the attribute did not provide a type, then default to NoneType.
743   if (!storage->getType())
744     storage->setType(NoneType::get(ctx));
745 }
746 
747 BoolAttr BoolAttr::get(bool value, MLIRContext *context) {
748   return value ? context->getImpl().trueAttr : context->getImpl().falseAttr;
749 }
750 
751 UnitAttr UnitAttr::get(MLIRContext *context) {
752   return context->getImpl().unitAttr;
753 }
754 
755 Location UnknownLoc::get(MLIRContext *context) {
756   return context->getImpl().unknownLocAttr;
757 }
758 
759 /// Return empty dictionary.
760 DictionaryAttr DictionaryAttr::getEmpty(MLIRContext *context) {
761   return context->getImpl().emptyDictionaryAttr;
762 }
763 
764 //===----------------------------------------------------------------------===//
765 // AffineMap uniquing
766 //===----------------------------------------------------------------------===//
767 
768 StorageUniquer &MLIRContext::getAffineUniquer() {
769   return getImpl().affineUniquer;
770 }
771 
772 AffineMap AffineMap::getImpl(unsigned dimCount, unsigned symbolCount,
773                              ArrayRef<AffineExpr> results,
774                              MLIRContext *context) {
775   auto &impl = context->getImpl();
776   auto key = std::make_tuple(dimCount, symbolCount, results);
777 
778   // Safely get or create an AffineMap instance.
779   return safeGetOrCreate(
780       impl.affineMaps, key, impl.affineMutex, impl.threadingIsEnabled, [&] {
781         auto *res = impl.affineAllocator.Allocate<detail::AffineMapStorage>();
782 
783         // Copy the results into the bump pointer.
784         results = copyArrayRefInto(impl.affineAllocator, results);
785 
786         // Initialize the memory using placement new.
787         new (res)
788             detail::AffineMapStorage{dimCount, symbolCount, results, context};
789         return AffineMap(res);
790       });
791 }
792 
793 AffineMap AffineMap::get(MLIRContext *context) {
794   return getImpl(/*dimCount=*/0, /*symbolCount=*/0, /*results=*/{}, context);
795 }
796 
797 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
798                          MLIRContext *context) {
799   return getImpl(dimCount, symbolCount, /*results=*/{}, context);
800 }
801 
802 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
803                          AffineExpr result) {
804   return getImpl(dimCount, symbolCount, {result}, result.getContext());
805 }
806 
807 AffineMap AffineMap::get(unsigned dimCount, unsigned symbolCount,
808                          ArrayRef<AffineExpr> results, MLIRContext *context) {
809   return getImpl(dimCount, symbolCount, results, context);
810 }
811 
812 //===----------------------------------------------------------------------===//
813 // Integer Sets: these are allocated into the bump pointer, and are immutable.
814 // Unlike AffineMap's, these are uniqued only if they are small.
815 //===----------------------------------------------------------------------===//
816 
817 IntegerSet IntegerSet::get(unsigned dimCount, unsigned symbolCount,
818                            ArrayRef<AffineExpr> constraints,
819                            ArrayRef<bool> eqFlags) {
820   // The number of constraints can't be zero.
821   assert(!constraints.empty());
822   assert(constraints.size() == eqFlags.size());
823 
824   auto &impl = constraints[0].getContext()->getImpl();
825 
826   // A utility function to construct a new IntegerSetStorage instance.
827   auto constructorFn = [&] {
828     auto *res = impl.affineAllocator.Allocate<detail::IntegerSetStorage>();
829 
830     // Copy the results and equality flags into the bump pointer.
831     constraints = copyArrayRefInto(impl.affineAllocator, constraints);
832     eqFlags = copyArrayRefInto(impl.affineAllocator, eqFlags);
833 
834     // Initialize the memory using placement new.
835     new (res)
836         detail::IntegerSetStorage{dimCount, symbolCount, constraints, eqFlags};
837     return IntegerSet(res);
838   };
839 
840   // If this instance is uniqued, then we handle it separately so that multiple
841   // threads may simultaneously access existing instances.
842   if (constraints.size() < IntegerSet::kUniquingThreshold) {
843     auto key = std::make_tuple(dimCount, symbolCount, constraints, eqFlags);
844     return safeGetOrCreate(impl.integerSets, key, impl.affineMutex,
845                            impl.threadingIsEnabled, constructorFn);
846   }
847 
848   // Otherwise, acquire a writer-lock so that we can safely create the new
849   // instance.
850   ScopedWriterLock affineLock(impl.affineMutex, impl.threadingIsEnabled);
851   return constructorFn();
852 }
853 
854 //===----------------------------------------------------------------------===//
855 // StorageUniquerSupport
856 //===----------------------------------------------------------------------===//
857 
858 /// Utility method to generate a default location for use when checking the
859 /// construction invariants of a storage object. This is defined out-of-line to
860 /// avoid the need to include Location.h.
861 const AttributeStorage *
862 mlir::detail::generateUnknownStorageLocation(MLIRContext *ctx) {
863   return reinterpret_cast<const AttributeStorage *>(
864       ctx->getImpl().unknownLocAttr.getAsOpaquePointer());
865 }
866