Merge pull request #38147 from slavapestov/requirement-machine-queries

RequirementMachine: Implement some generic signature queries

Author: slavapestov

include/swift/AST/GenericSignature.h

@@ -33,6 +33,7 @@ namespace swift {
 class GenericSignatureBuilder;
 class ProtocolConformanceRef;
 class ProtocolType;
+class RequirementMachine;
 class SubstitutionMap;
 class GenericEnvironment;
 
@@ -303,6 +304,9 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   /// Retrieve the generic signature builder for the given generic signature.
   GenericSignatureBuilder *getGenericSignatureBuilder() const;
 
+  /// Retrieve the requirement machine for the given generic signature.
+  RequirementMachine *getRequirementMachine() const;
+
   /// Returns the generic environment that provides fresh contextual types
   /// (archetypes) that correspond to the interface types in this generic
   /// signature.

include/swift/AST/RequirementMachine.h

@@ -13,15 +13,21 @@
 #ifndef SWIFT_REQUIREMENTMACHINE_H
 #define SWIFT_REQUIREMENTMACHINE_H
 
+#include "swift/AST/GenericSignature.h"
+
+namespace llvm {
+class raw_ostream;
+}
+
 namespace swift {
 
 class ASTContext;
 class AssociatedTypeDecl;
-class CanGenericSignature;
 class CanType;
-class GenericSignature;
+class LayoutConstraint;
 class ProtocolDecl;
 class Requirement;
+class Type;
 
 /// Wraps a rewrite system with higher-level operations in terms of
 /// generic signatures and interface types.
@@ -43,10 +49,20 @@ class RequirementMachine final {
   void addGenericSignature(CanGenericSignature sig);
 
   bool isComplete() const;
-  void markComplete();
+  void computeCompletion(CanGenericSignature sig);
 
 public:
   ~RequirementMachine();
+
+  // Generic signature queries
+  bool requiresClass(Type depType) const;
+  LayoutConstraint getLayoutConstraint(Type depType) const;
+  bool requiresProtocol(Type depType, const ProtocolDecl *proto) const;
+  GenericSignature::RequiredProtocols getRequiredProtocols(Type depType) const;
+  bool isConcreteType(Type depType) const;
+  bool areSameTypeParameterInContext(Type depType1, Type depType2) const;
+
+  void dump(llvm::raw_ostream &out) const;
 };
 
 } // end namespace swift

include/swift/AST/TypeMatcher.h

@@ -195,9 +195,21 @@ class TypeMatcher {
     TRIVIAL_CASE(ModuleType)
     TRIVIAL_CASE(DynamicSelfType)
     TRIVIAL_CASE(ArchetypeType)
-    TRIVIAL_CASE(GenericTypeParamType)
     TRIVIAL_CASE(DependentMemberType)
 
+    bool visitGenericTypeParamType(CanGenericTypeParamType firstType,
+                                   Type secondType,
+                                   Type sugaredFirstType) {
+      /* If the types match, continue. */
+      if (!Matcher.asDerived().alwaysMismatchGenericParams() &&
+          firstType->isEqual(secondType))
+        return true;
+
+      /* Otherwise, let the derived class deal with the mismatch. */
+      return mismatch(firstType.getPointer(), secondType,
+                      sugaredFirstType);
+    }
+
     /// FIXME: Split this out into cases?
     bool visitAnyFunctionType(CanAnyFunctionType firstFunc, Type secondType,
                               Type sugaredFirstType) {
@@ -300,6 +312,8 @@ class TypeMatcher {
 #undef TRIVIAL_CASE
   };
 
+  bool alwaysMismatchGenericParams() const { return false; }
+
   ImplClass &asDerived() { return static_cast<ImplClass &>(*this); }
 
   const ImplClass &asDerived() const {

include/swift/Basic/LangOptions.h

@@ -453,7 +453,7 @@ namespace swift {
 
     /// Maximum iteration count for requirement machine confluent completion
     /// algorithm.
-    unsigned RequirementMachineStepLimit = 1000;
+    unsigned RequirementMachineStepLimit = 2000;
 
     /// Maximum term length for requirement machine confluent completion
     /// algorithm.

include/swift/Basic/Statistics.def

@@ -224,10 +224,12 @@ FRONTEND_STATISTIC(Sema, NumAccessorBodiesSynthesized)
 /// amount of work the requirement machine does analyzing type signatures.
 FRONTEND_STATISTIC(Sema, NumRequirementMachines)
 
-/// Number of requirement machines constructed. Rough proxy for
-/// amount of work the requirement machine does analyzing type signatures.
+/// Number of new rules added by Knuth-Bendix completion procedure.
 FRONTEND_STATISTIC(Sema, NumRequirementMachineCompletionSteps)
 
+/// Number of new rules added by concrete term unification.
+FRONTEND_STATISTIC(Sema, NumRequirementMachineUnifiedConcreteTerms)
+
 /// Number of generic signature builders constructed. Rough proxy for
 /// amount of work the GSB does analyzing type signatures.
 FRONTEND_STATISTIC(Sema, NumGenericSignatureBuilders)

lib/AST/CMakeLists.txt

@@ -73,6 +73,7 @@ add_swift_host_library(swiftAST STATIC
   ProtocolConformance.cpp
   RawComment.cpp
   RequirementEnvironment.cpp
+  RequirementMachine/EquivalenceClassMap.cpp
   RequirementMachine/ProtocolGraph.cpp
   RequirementMachine/RequirementMachine.cpp
   RequirementMachine/RewriteSystem.cpp