RequirementMachine: Stub out the equivalence class map

Author: slavapestov

include/swift/AST/RequirementMachine.h

@@ -43,7 +43,7 @@ class RequirementMachine final {
   void addGenericSignature(CanGenericSignature sig);
 
   bool isComplete() const;
-  void markComplete();
+  void computeCompletion(CanGenericSignature sig);
 
 public:
   ~RequirementMachine();

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