[Compile perf] rdar://27397701 Typecheck synthetic accessors more lazily

Author: graydon

lib/Sema/CodeSynthesis.cpp

@@ -763,17 +763,15 @@ void swift::addTrivialAccessorsToStorage(AbstractStorageDecl *storage,
 
   // Synthesize and type-check the body of the getter.
   synthesizeTrivialGetter(getter, storage, TC);
-  TC.typeCheckDecl(getter, true);
-  TC.typeCheckDecl(getter, false);
+  TC.validateDecl(getter);
 
   if (setter) {
     if (isDynamic)
       setter->getAttrs().add(new (TC.Context) DynamicAttr(IsImplicit));
 
     // Synthesize and type-check the body of the setter.
     synthesizeTrivialSetter(setter, storage, setterValueParam, TC);
-    TC.typeCheckDecl(setter, true);
-    TC.typeCheckDecl(setter, false);
+    TC.validateDecl(setter);
   }
 
   auto *DC = storage->getDeclContext();

lib/Sema/TypeCheckDecl.cpp

@@ -3615,6 +3615,21 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       }
     }
 
+    // Typecheck any accessors that were previously synthesized
+    // (that were previously only validated at point of synthesis)
+    if (auto getter = VD->getGetter()) {
+      if (getter->hasBody()) {
+        TC.typeCheckDecl(getter, true);
+        TC.typeCheckDecl(getter, false);
+      }
+    }
+    if (auto setter = VD->getSetter()) {
+      if (setter->hasBody()) {
+        TC.typeCheckDecl(setter, true);
+        TC.typeCheckDecl(setter, false);
+      }
+    }
+
     TC.checkDeclAttributes(VD);
   }
 

lib/Sema/TypeChecker.cpp

@@ -505,6 +505,7 @@ static void typeCheckFunctionsAndExternalDecls(TypeChecker &TC) {
 
   } while (currentFunctionIdx < TC.definedFunctions.size() ||
            currentExternalDef < TC.Context.ExternalDefinitions.size() ||
+           !TC.ValidatedTypes.empty() ||
            !TC.UsedConformances.empty());
 
   // FIXME: Horrible hack. Store this somewhere more appropriate.