Merge pull request #17643 from DougGregor/evaluator-indirect-evaluation

[Evaluator] Separate formation of a request from evaluation of that request

Author: slavapestov

include/swift/AST/DiagnosticsCommon.def

@@ -93,6 +93,24 @@ ERROR(attr_only_on_parameters, none,
 ERROR(function_type_no_parens,none,
       "single argument function types require parentheses", ())
 
+//------------------------------------------------------------------------------
+// MARK: Circular reference diagnostics
+//------------------------------------------------------------------------------
+ERROR(circular_reference, none,
+      "circular reference", ())
+
+ERROR(redundant_type_alias_define, none,
+      "redundant type alias declaration", ())
+
+NOTE(circular_reference_through, none,
+     "through reference here", ())
+
+ERROR(circular_class_inheritance,none,
+      "%0 inherits from itself", (Identifier))
+
+ERROR(circular_enum_inheritance,none,
+      "%0 has a raw type that depends on itself", (Identifier))
+
 #ifndef DIAG_NO_UNDEF
 # if defined(DIAG)
 #  undef DIAG

include/swift/AST/DiagnosticsSema.def

@@ -2155,8 +2155,6 @@ ERROR(superclass_not_open,none,
 NOTE(superclass_here,none,"superclass is declared here", ())
 ERROR(superclass_of_open_not_open,none,
   "superclass %0 of open class must be open", (Type))
-ERROR(circular_class_inheritance,none,
-      "%0 inherits from itself", (Identifier))
 ERROR(inheritance_from_final_class,none,
       "inheritance from a final class %0", (Identifier))
 ERROR(inheritance_from_unspecialized_objc_generic_class,none,
@@ -2199,8 +2197,6 @@ ERROR(enum_stored_property,none,
 // Enum raw types
 ERROR(multiple_enum_raw_types,none,
   "multiple enum raw types %0 and %1", (Type, Type))
-ERROR(circular_enum_inheritance,none,
-      "%0 has a raw type that depends on itself", (Identifier))
 ERROR(raw_type_not_first,none,
   "raw type %0 must appear first in the enum inheritance clause", (Type))
 ERROR(raw_type_not_literal_convertible,none,
@@ -4061,18 +4057,6 @@ WARNING(variable_never_read, none,
         "%select{variable|parameter}1 %0 was written to, but never read",
         (Identifier, unsigned))
 
-//------------------------------------------------------------------------------
-// MARK: Circular reference diagnostics
-//------------------------------------------------------------------------------
-ERROR(circular_reference, none,
-      "circular reference", ())
-
-ERROR(redundant_type_alias_define, none,
-      "redundant type alias declaration", ())
-
-NOTE(circular_reference_through, none,
-     "through reference here", ())
-
 //------------------------------------------------------------------------------
 // MARK: Debug diagnostics
 //------------------------------------------------------------------------------

include/swift/AST/Evaluator.h

@@ -37,12 +37,23 @@ class raw_ostream;
 
 namespace swift {
 
+using llvm::ArrayRef;
 using llvm::Optional;
 using llvm::None;
 
 class DiagnosticEngine;
+class Evaluator;
 class UnifiedStatsReporter;
 
+/// An "abstract" request function pointer, which is the storage type
+/// used for each of the
+using AbstractRequestFunction = void(void);
+
+/// Form the specific request function for the given request type.
+template<typename Request>
+using RequestFunction =
+    typename Request::OutputType(const Request &, Evaluator &);
+
 /// Pretty stack trace handler for an arbitrary request.
 template<typename Request>
 class PrettyStackTraceRequest : public llvm::PrettyStackTraceEntry {
@@ -59,7 +70,7 @@ class PrettyStackTraceRequest : public llvm::PrettyStackTraceEntry {
 };
 
 /// Report that a request of the given kind is being evaluated, so it
-/// can be recoded by the stats reporter.
+/// can be recorded by the stats reporter.
 template<typename Request>
 void reportEvaluatedRequest(UnifiedStatsReporter &stats,
                             const Request &request) { }
@@ -138,6 +149,18 @@ class Evaluator {
   /// non-null.
   UnifiedStatsReporter *stats = nullptr;
 
+  /// A vector containing the abstract request functions that can compute
+  /// the result of a particular request within a given zone. The
+  /// \c uint8_t is the zone number of the request, and the array is
+  /// indexed by the index of the request type within that zone. Each
+  /// entry is a function pointer that will be reinterpret_cast'd to
+  ///
+  ///   RequestType::OutputType (*)(const RequestType &request,
+  ///                               Evaluator &evaluator);
+  /// and called to satisfy the request.
+  std::vector<std::pair<uint8_t, ArrayRef<AbstractRequestFunction *>>>
+    requestFunctionsByZone;
+
   /// A vector containing all of the active evaluation requests, which
   /// is treated as a stack and is used to detect cycles.
   llvm::SetVector<AnyRequest> activeRequests;
@@ -156,6 +179,19 @@ class Evaluator {
   /// so all clients must cope with cycles.
   llvm::DenseMap<AnyRequest, std::vector<AnyRequest>> dependencies;
 
+  /// Retrieve the request function for the given zone and request IDs.
+  AbstractRequestFunction *getAbstractRequestFunction(uint8_t zoneID,
+                                                      uint8_t requestID) const;
+
+  /// Retrieve the request function for the given request type.
+  template<typename Request>
+  auto getRequestFunction() const -> RequestFunction<Request> * {
+    auto abstractFn = getAbstractRequestFunction(TypeID<Request>::zoneID,
+                                                 TypeID<Request>::localID);
+    assert(abstractFn && "No request function for request");
+    return reinterpret_cast<RequestFunction<Request> *>(abstractFn);
+  }
+
 public:
   /// Construct a new evaluator that can emit cyclic-dependency
   /// diagnostics through the given diagnostics engine.
@@ -165,6 +201,13 @@ class Evaluator {
   /// statistics will be recorded.
   void setStatsReporter(UnifiedStatsReporter *stats) { this->stats = stats; }
 
+  /// Register the set of request functions for the given zone.
+  ///
+  /// These functions will be called to evaluate any requests within that
+  /// zone.
+  void registerRequestFunctions(uint8_t zoneID,
+                                ArrayRef<AbstractRequestFunction *> functions);
+
   /// Evaluate the given request and produce its result,
   /// consulting/populating the cache as required.
   template<typename Request>
@@ -247,7 +290,7 @@ class Evaluator {
     /// Update statistics.
     if (stats) reportEvaluatedRequest(*stats, request);
 
-    return request(*this);
+    return getRequestFunction<Request>()(request, *this);
   }
 
   /// Get the result of a request, consulting an external cache
@@ -260,17 +303,8 @@ class Evaluator {
     if (auto cached = request.getCachedResult())
       return *cached;
 
-    // Clear out the dependencies on this request; we're going to recompute
-    // them now anyway.
-    dependencies[request].clear();
-
-    PrettyStackTraceRequest<Request> prettyStackTrace(request);
-
-    /// Update statistics.
-    if (stats) reportEvaluatedRequest(*stats, request);
-
-    // Service the request.
-    auto result = request(*this);
+    // Compute the result.
+    auto result = getResultUncached(request);
 
     // Cache the result.
     request.cacheResult(result);
@@ -293,12 +327,8 @@ class Evaluator {
       return known->second.castTo<typename Request::OutputType>();
     }
 
-    // Clear out the dependencies on this request; we're going to recompute
-    // them now anyway.
-    dependencies[request].clear();
-
-    // Evaluate the request.
-    auto result = request(*this);
+    // Compute the result.
+    auto result = getResultUncached(request);
 
     // Cache the result.
     cache.insert({anyRequest, result});
@@ -314,7 +344,7 @@ class Evaluator {
                          llvm::raw_ostream &out,
                          llvm::DenseSet<AnyRequest> &visitedAnywhere,
                          llvm::SmallVectorImpl<AnyRequest> &visitedAlongPath,
-                         llvm::ArrayRef<AnyRequest> highlightPath,
+                         ArrayRef<AnyRequest> highlightPath,
                          std::string &prefixStr,
                          bool lastChild) const;
 

include/swift/AST/LazyResolver.h

@@ -71,20 +71,6 @@ class LazyResolver {
   /// Resolve the "is Objective-C" bit for the given declaration.
   virtual void resolveIsObjC(ValueDecl *VD) = 0;
 
-  /// Retrieve the superclass of the given class.
-  virtual Type getSuperclass(const ClassDecl *classDecl) = 0;
-
-  /// Retrieve the superclass of the given protocol.
-  virtual Type getSuperclass(const ProtocolDecl *protocolDecl) = 0;
-
-  /// Resolve the raw type of the given enum.
-  virtual Type getRawType(EnumDecl *enumDecl) = 0;
-
-  /// Get a specific inherited type from the given declaration.
-  virtual Type getInheritedType(
-                        llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
-                        unsigned index) = 0;
-
   /// Resolve the trailing where clause of the given protocol in-place.
   virtual void resolveTrailingWhereClause(ProtocolDecl *proto) = 0;
 

include/swift/AST/SimpleRequest.h

@@ -56,7 +56,7 @@ enum class CacheKind {
 /// important one takes an evaluator and the input values, then computes the
 /// final result:
 /// \code
-///   Output operator()(Evaluator &evaluator, Inputs...) const;
+///   Output evaluate(Evaluator &evaluator, Inputs...) const;
 /// \endcode
 ///
 /// The \c Derived class will also need to implement an operation to break a
@@ -105,8 +105,8 @@ class SimpleRequest {
   template<size_t ...Indices>
   Output callDerived(Evaluator &evaluator,
                      llvm::index_sequence<Indices...>) const {
-    static_assert(sizeof...(Indices) > 0, "Subclass must define operator()");
-    return asDerived()(evaluator, std::get<Indices>(storage)...);
+    static_assert(sizeof...(Indices) > 0, "Subclass must define evaluate()");
+    return asDerived().evaluate(evaluator, std::get<Indices>(storage)...);
   }
 
   template<size_t ...Indices>
@@ -130,8 +130,11 @@ class SimpleRequest {
   explicit SimpleRequest(const Inputs& ...inputs)
     : storage(inputs...) { }
 
-  OutputType operator()(Evaluator &evaluator) const {
-    return callDerived(evaluator, llvm::index_sequence_for<Inputs...>());
+  /// Request evaluation function that will be registered with the evaluator.
+  static OutputType evaluateRequest(const Derived &request,
+                                    Evaluator &evaluator) {
+    return request.callDerived(evaluator,
+                               llvm::index_sequence_for<Inputs...>());
   }
 
   void diagnoseCycle(DiagnosticEngine &diags) const {

include/swift/Sema/TypeCheckRequests.h renamed to include/swift/AST/TypeCheckRequests.h

@@ -46,15 +46,14 @@ class InheritedTypeRequest :
 
 public:
   using SimpleRequest::SimpleRequest;
-  using SimpleRequest::operator();
 
 private:
   friend class SimpleRequest;
 
   // Evaluation.
-  Type operator()(Evaluator &evaluator,
-                  llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
-                  unsigned index) const;
+  Type evaluate(Evaluator &evaluator,
+                llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
+                unsigned index) const;
 
 public:
   // Cycle handling
@@ -76,13 +75,12 @@ class SuperclassTypeRequest :
                          NominalTypeDecl *> {
 public:
   using SimpleRequest::SimpleRequest;
-  using SimpleRequest::operator();
 
 private:
   friend class SimpleRequest;
 
   // Evaluation.
-  Type operator()(Evaluator &evaluator, NominalTypeDecl *classDecl) const;
+  Type evaluate(Evaluator &evaluator, NominalTypeDecl *classDecl) const;
 
 public:
   // Cycle handling
@@ -104,13 +102,12 @@ class EnumRawTypeRequest :
                          EnumDecl *> {
 public:
   using SimpleRequest::SimpleRequest;
-  using SimpleRequest::operator();
 
 private:
   friend class SimpleRequest;
 
   // Evaluation.
-  Type operator()(Evaluator &evaluator, EnumDecl *enumDecl) const;
+  Type evaluate(Evaluator &evaluator, EnumDecl *enumDecl) const;
 
 public:
   // Cycle handling
@@ -124,8 +121,11 @@ class EnumRawTypeRequest :
   void cacheResult(Type value) const;
 };
 
-#define SWIFT_TYPEID_ZONE 10
-#define SWIFT_TYPEID_HEADER "swift/Sema/TypeCheckerTypeIDZone.def"
+/// The zone number for the type checker.
+#define SWIFT_TYPE_CHECKER_REQUESTS_TYPEID_ZONE 10
+
+#define SWIFT_TYPEID_ZONE SWIFT_TYPE_CHECKER_REQUESTS_TYPEID_ZONE
+#define SWIFT_TYPEID_HEADER "swift/AST/TypeCheckerTypeIDZone.def"
 #include "swift/Basic/DefineTypeIDZone.h"
 
 // Set up reporting of evaluated requests.
@@ -135,7 +135,7 @@ inline void reportEvaluatedRequest(UnifiedStatsReporter &stats,  \
                             const RequestType &request) {        \
   ++stats.getFrontendCounters().RequestType;                     \
 }
-#include "swift/Sema/TypeCheckerTypeIDZone.def"
+#include "swift/AST/TypeCheckerTypeIDZone.def"
 #undef SWIFT_TYPEID
 
 } // end namespace swift

include/swift/Sema/TypeCheckerTypeIDZone.def renamed to include/swift/AST/TypeCheckerTypeIDZone.def

@@ -1,4 +1,4 @@
-//===--- ArithmeticEvaluatorTypeIDZone.def - --------------------*- C++ -*-===//
+//===--- TypeCheckerTypeIDZone.def ------------------------------*- C++ -*-===//
 //
 // This source file is part of the Swift.org open source project
 //

include/swift/Basic/DefineTypeIDZone.h

@@ -46,15 +46,15 @@ template<> struct TypeIDZoneTypes<SWIFT_TYPEID_ZONE> {
 };
 
 // Second pass: create specializations of TypeID for these types.
-#define SWIFT_TYPEID_NAMED(Type, Name)                    \
-template<> struct TypeID<Type> {                          \
-  static const uint64_t value =                           \
-    formTypeID(SWIFT_TYPEID_ZONE,                         \
-               TypeIDZoneTypes<SWIFT_TYPEID_ZONE>::Name); \
-                                                          \
-  static llvm::StringRef getName() {                      \
-    return #Name;                                         \
-  }                                                       \
+#define SWIFT_TYPEID_NAMED(Type, Name)                       \
+template<> struct TypeID<Type> {                             \
+  static const uint8_t zoneID = SWIFT_TYPEID_ZONE;           \
+  static const uint8_t localID =                             \
+    TypeIDZoneTypes<SWIFT_TYPEID_ZONE>::Name;                \
+                                                             \
+  static const uint64_t value = formTypeID(zoneID, localID); \
+                                                             \
+  static llvm::StringRef getName() { return #Name; }         \
 };
 
 #define SWIFT_TYPEID_TEMPLATE1_NAMED(Template, Name, Param1, Arg1)    \

include/swift/Basic/Statistics.def

@@ -197,7 +197,7 @@ FRONTEND_STATISTIC(Sema, NumUnloadedLazyIterableDeclContexts)
 
 /// All type check requests go into the Sema area.
 #define SWIFT_TYPEID(NAME) FRONTEND_STATISTIC(Sema, NAME)
-#include "swift/Sema/TypeCheckerTypeIDZone.def"
+#include "swift/AST/TypeCheckerTypeIDZone.def"
 #undef SWIFT_TYPEID
 
 /// The next 10 statistics count 5 kinds of SIL entities present

include/swift/Subsystems.h

@@ -46,6 +46,7 @@ namespace swift {
   class DelayedParsingCallbacks;
   class DiagnosticConsumer;
   class DiagnosticEngine;
+  class Evaluator;
   class FileUnit;
   class GenericEnvironment;
   class GenericParamList;
@@ -342,6 +343,13 @@ namespace swift {
     struct Implementation;
     Implementation &Impl;
   };
+
+  /// Register the type checker's request functions with the evaluator.
+  ///
+  /// Clients that form an ASTContext and will perform any semantic
+  /// queries should call this function after forming the ASTContext.
+  void registerTypeCheckerRequestFunctions(Evaluator &evaluator);
+
 } // end namespace swift
 
 #endif // SWIFT_SUBSYSTEMS_H

lib/AST/CMakeLists.txt

@@ -52,6 +52,7 @@ add_swift_library(swiftAST STATIC
   SubstitutionMap.cpp
   SwiftNameTranslation.cpp
   Type.cpp
+  TypeCheckRequests.cpp
   TypeJoinMeet.cpp
   TypeRefinementContext.cpp
   TypeRepr.cpp