---

yaml
---
r: 340855
b: refs/heads/rxwei-patch-1
c: 0ec33bf
h: refs/heads/master
i:
  340853: c7ae1ed
  340851: 375c883
  340847: 58779b0

Author: slavapestov

[refs]

@@ -1015,7 +1015,7 @@ refs/tags/swift-DEVELOPMENT-SNAPSHOT-2018-08-18-a: b10b1fce14385faa6d44f6b933e95
 refs/heads/rdar-43033749-fix-batch-mode-no-diags-swift-5.0-branch: a14e64eaad30de89f0f5f0b2a782eed7ecdcb255
 refs/heads/revert-19006-error-bridging-integer-type: 8a9065a3696535305ea53fe9b71f91cbe6702019
 refs/heads/revert-19050-revert-19006-error-bridging-integer-type: ecf752d54b05dd0a20f510f0bfa54a3fec3bcaca
-refs/heads/rxwei-patch-1: 4df9543ee89fd64580a0f128db2b06dd03f7c09c
+refs/heads/rxwei-patch-1: 0ec33bfa4ac8b6f2ad42090fe31258d8c3ce41bf
 refs/heads/shahmishal-patch-1: e58ec0f7488258d42bef51bc3e6d7b3dc74d7b2a
 refs/heads/typelist-existential: 4046359efd541fb5c72d69a92eefc0a784df8f5e
 refs/tags/swift-4.2-DEVELOPMENT-SNAPSHOT-2018-08-20-a: 4319ba09e4fb8650ee86061075c74a016b6baab9

branches/rxwei-patch-1/include/swift/AST/Decl.h

@@ -4384,6 +4384,7 @@ class AbstractStorageDecl : public ValueDecl {
   friend class SetterAccessLevelRequest;
   friend class IsGetterMutatingRequest;
   friend class IsSetterMutatingRequest;
+  friend class OpaqueReadOwnershipRequest;
 
 public:
   static const size_t MaxNumAccessors = 255;
@@ -4457,6 +4458,8 @@ class AbstractStorageDecl : public ValueDecl {
     unsigned IsGetterMutating : 1;
     unsigned IsSetterMutatingComputed : 1;
     unsigned IsSetterMutating : 1;
+    unsigned OpaqueReadOwnershipComputed : 1;
+    unsigned OpaqueReadOwnership : 2;
   } LazySemanticInfo = { };
 
 protected:
@@ -4466,8 +4469,6 @@ class AbstractStorageDecl : public ValueDecl {
     : ValueDecl(Kind, DC, Name, NameLoc) {
     Bits.AbstractStorageDecl.HasStorage = true;
     Bits.AbstractStorageDecl.SupportsMutation = supportsMutation;
-    Bits.AbstractStorageDecl.OpaqueReadOwnership =
-      unsigned(OpaqueReadOwnership::Owned);
     Bits.AbstractStorageDecl.IsStatic = IsStatic;
   }
 
@@ -4551,11 +4552,10 @@ class AbstractStorageDecl : public ValueDecl {
   }
 
   /// Return the ownership of values opaquely read from this storage.
-  OpaqueReadOwnership getOpaqueReadOwnership() const {
-    return OpaqueReadOwnership(Bits.AbstractStorageDecl.OpaqueReadOwnership);
-  }
+  OpaqueReadOwnership getOpaqueReadOwnership() const;
   void setOpaqueReadOwnership(OpaqueReadOwnership ownership) {
-    Bits.AbstractStorageDecl.OpaqueReadOwnership = unsigned(ownership);
+    LazySemanticInfo.OpaqueReadOwnership = unsigned(ownership);
+    LazySemanticInfo.OpaqueReadOwnershipComputed = true;
   }
 
   /// Return true if reading this storage requires the ability to

branches/rxwei-patch-1/include/swift/AST/TypeCheckRequests.h

@@ -37,6 +37,7 @@ class TypeAliasDecl;
 struct TypeLoc;
 class ValueDecl;
 class AbstractStorageDecl;
+enum class OpaqueReadOwnership: uint8_t;
 
 /// Display a nominal type or extension thereof.
 void simple_display(
@@ -754,6 +755,33 @@ class IsSetterMutatingRequest :
   void cacheResult(bool value) const;
 };
 
+/// Request whether reading the storage yields a borrowed value.
+class OpaqueReadOwnershipRequest :
+    public SimpleRequest<OpaqueReadOwnershipRequest,
+                         CacheKind::SeparatelyCached,
+                         OpaqueReadOwnership,
+                         AbstractStorageDecl *> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  llvm::Expected<OpaqueReadOwnership>
+  evaluate(Evaluator &evaluator, AbstractStorageDecl *storage) const;
+
+public:
+  // Cycle handling
+  void diagnoseCycle(DiagnosticEngine &diags) const;
+  void noteCycleStep(DiagnosticEngine &diags) const;
+
+  // Separate caching.
+  bool isCached() const { return true; }
+  Optional<OpaqueReadOwnership> getCachedResult() const;
+  void cacheResult(OpaqueReadOwnership value) const;
+};
+
 // Allow AnyValue to compare two Type values, even though Type doesn't
 // support ==.
 template<>

branches/rxwei-patch-1/include/swift/AST/TypeCheckerTypeIDZone.def

@@ -38,3 +38,4 @@ SWIFT_TYPEID(FunctionBuilderTypeRequest)
 SWIFT_TYPEID(SelfAccessKindRequest)
 SWIFT_TYPEID(IsGetterMutatingRequest)
 SWIFT_TYPEID(IsSetterMutatingRequest)
+SWIFT_TYPEID(OpaqueReadOwnershipRequest)

branches/rxwei-patch-1/lib/AST/Decl.cpp

@@ -2068,6 +2068,12 @@ bool AbstractStorageDecl::isSetterMutating() const {
     IsSetterMutatingRequest{const_cast<AbstractStorageDecl *>(this)}, {});
 }
 
+OpaqueReadOwnership AbstractStorageDecl::getOpaqueReadOwnership() const {
+  ASTContext &ctx = getASTContext();
+  return evaluateOrDefault(ctx.evaluator,
+    OpaqueReadOwnershipRequest{const_cast<AbstractStorageDecl *>(this)}, {});
+}
+
 bool ValueDecl::isInstanceMember() const {
   DeclContext *DC = getDeclContext();
   if (!DC->isTypeContext())

branches/rxwei-patch-1/lib/AST/TypeCheckRequests.cpp

@@ -813,4 +813,31 @@ Optional<bool> IsSetterMutatingRequest::getCachedResult() const {
 void IsSetterMutatingRequest::cacheResult(bool value) const {
   auto *storage = std::get<0>(getStorage());
   storage->setIsSetterMutating(value);
-}
+}
+
+//----------------------------------------------------------------------------//
+// OpaqueReadOwnershipRequest computation.
+//----------------------------------------------------------------------------//
+
+void OpaqueReadOwnershipRequest::diagnoseCycle(DiagnosticEngine &diags) const {
+  auto decl = std::get<0>(getStorage());
+  diags.diagnose(decl, diag::circular_reference);
+}
+
+void OpaqueReadOwnershipRequest::noteCycleStep(DiagnosticEngine &diags) const {
+  auto decl = std::get<0>(getStorage());
+  diags.diagnose(decl, diag::circular_reference_through);
+}
+
+Optional<OpaqueReadOwnership>
+OpaqueReadOwnershipRequest::getCachedResult() const {
+  auto *storage = std::get<0>(getStorage());
+  if (storage->LazySemanticInfo.OpaqueReadOwnershipComputed)
+    return OpaqueReadOwnership(storage->LazySemanticInfo.OpaqueReadOwnership);
+  return None;
+}
+
+void OpaqueReadOwnershipRequest::cacheResult(OpaqueReadOwnership value) const {
+  auto *storage = std::get<0>(getStorage());
+  storage->setOpaqueReadOwnership(value);
+}

branches/rxwei-patch-1/lib/Sema/TypeCheckDecl.cpp

@@ -2118,8 +2118,12 @@ IsSetterMutatingRequest::evaluate(Evaluator &evaluator,
   llvm_unreachable("bad storage kind");
 }
 
-static bool shouldUseOpaqueReadAccessor(AbstractStorageDecl *storage) {
-  return storage->getAttrs().hasAttribute<BorrowedAttr>();
+llvm::Expected<OpaqueReadOwnership>
+OpaqueReadOwnershipRequest::evaluate(Evaluator &evaluator,
+                                     AbstractStorageDecl *storage) const {
+  return (storage->getAttrs().hasAttribute<BorrowedAttr>()
+          ? OpaqueReadOwnership::Borrowed
+          : OpaqueReadOwnership::Owned);
 }
 
 static void validateAbstractStorageDecl(TypeChecker &TC,
@@ -2129,9 +2133,6 @@ static void validateAbstractStorageDecl(TypeChecker &TC,
       sf->markDeclWithOpaqueResultTypeAsValidated(storage);
     }
   }
-  
-  if (shouldUseOpaqueReadAccessor(storage))
-    storage->setOpaqueReadOwnership(OpaqueReadOwnership::Borrowed);
 
   // Everything else about the accessors can wait until finalization.
   // This will validate all the accessors.