Sema: Small optimization for StoredPropertiesRequest

If the nominal type was imported or deserialized, we don't have to worry
about unlowered lazy properties or property wrappers. Just scan through
the members looking for stored properties and that's it.

Author: slavapestov

lib/Sema/TypeCheckDecl.cpp

@@ -946,56 +946,44 @@ static bool contextAllowsPatternBindingWithoutVariables(DeclContext *dc) {
   return true;
 }
 
-static VarDecl *getStoredPropertyFor(VarDecl *var) {
-  if (var->isStatic())
-    return nullptr;
-
-  if (var->isLazyStorageProperty())
-    return nullptr;
+static bool hasStoredProperties(NominalTypeDecl *decl) {
+  return (isa<StructDecl>(decl) ||
+          (isa<ClassDecl>(decl) && !decl->hasClangNode()));
+}
 
-  if (var->getOriginalWrappedProperty())
-    return nullptr;
+static void computeLoweredStoredProperties(NominalTypeDecl *decl) {
+  // Just walk over the members of the type, forcing backing storage
+  // for lazy properties and property wrappers to be synthesized.
+  for (auto *member : decl->getMembers()) {
+    auto *var = dyn_cast<VarDecl>(member);
+    if (!var || var->isStatic())
+      continue;
 
-  if (var->getAttrs().hasAttribute<LazyAttr>()) {
-    if (auto *storage = var->getLazyStorageProperty()) {
-      assert(storage->hasStorage());
-      return storage;
-    }
+    if (var->getAttrs().hasAttribute<LazyAttr>())
+      (void) var->getLazyStorageProperty();
 
-    return nullptr;
+    if (var->hasAttachedPropertyWrapper())
+      (void) var->getPropertyWrapperBackingProperty();
   }
-
-  if (var->hasAttachedPropertyWrapper()) {
-    if (auto *storage = var->getPropertyWrapperBackingProperty()) {
-      assert(storage->hasStorage());
-      return storage;
-    }
-
-    return nullptr;
-  }
-
-  if (var->getAttrs().hasAttribute<NSManagedAttr>())
-    return nullptr;
-
-  if (!var->hasStorage())
-    return nullptr;
-
-  return var;
 }
 
 llvm::Expected<ArrayRef<VarDecl *>>
 StoredPropertiesRequest::evaluate(Evaluator &evaluator,
                                   NominalTypeDecl *decl) const {
-  if (isa<EnumDecl>(decl) ||
-      isa<ProtocolDecl>(decl) ||
-      (isa<ClassDecl>(decl) && decl->hasClangNode()))
+  if (!hasStoredProperties(decl))
     return ArrayRef<VarDecl *>();
 
   SmallVector<VarDecl *, 4> results;
+
+  // Unless we're in a source file we don't have to do anything
+  // special to lower lazy properties and property wrappers.
+  if (isa<SourceFile>(decl->getModuleScopeContext()))
+    computeLoweredStoredProperties(decl);
+
   for (auto *member : decl->getMembers()) {
     if (auto *var = dyn_cast<VarDecl>(member))
-      if (auto *storage = getStoredPropertyFor(var))
-        results.push_back(storage);
+      if (!var->isStatic() && var->hasStorage())
+        results.push_back(var);
   }
 
   return decl->getASTContext().AllocateCopy(results);
@@ -1004,16 +992,20 @@ StoredPropertiesRequest::evaluate(Evaluator &evaluator,
 llvm::Expected<ArrayRef<Decl *>>
 StoredPropertiesAndMissingMembersRequest::evaluate(Evaluator &evaluator,
                                                    NominalTypeDecl *decl) const {
-  if (isa<EnumDecl>(decl) ||
-      isa<ProtocolDecl>(decl) ||
-      (isa<ClassDecl>(decl) && decl->hasClangNode()))
+  if (!hasStoredProperties(decl))
     return ArrayRef<Decl *>();
 
   SmallVector<Decl *, 4> results;
+
+  // Unless we're in a source file we don't have to do anything
+  // special to lower lazy properties and property wrappers.
+  if (isa<SourceFile>(decl->getModuleScopeContext()))
+    computeLoweredStoredProperties(decl);
+
   for (auto *member : decl->getMembers()) {
     if (auto *var = dyn_cast<VarDecl>(member))
-      if (auto *storage = getStoredPropertyFor(var))
-        results.push_back(storage);
+      if (!var->isStatic() && var->hasStorage())
+        results.push_back(var);
 
     if (auto missing = dyn_cast<MissingMemberDecl>(member))
       if (missing->getNumberOfFieldOffsetVectorEntries() > 0)