Support runtime check of function types.

sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart b/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
index c162f557c6dbe96572cbfae62df10b7f1c0d00b9..cad88ac782533022d448aa63d67767e0ba1ec373 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/runtime_types.dart
@@ -20,6 +20,7 @@ class RuntimeTypes {
 
   final Map<ClassElement, Set<ClassElement>> rtiDependencies;
   final Set<ClassElement> classesNeedingRti;
+  final Set<Element> methodsNeedingRti;
   // The set of classes that use one of their type variables as expressions
   // to get the runtime type.
   final Set<ClassElement> classesUsingTypeVariableExpression;
@@ -30,6 +31,7 @@ class RuntimeTypes {
       : this.compiler = compiler,
         representationGenerator = new TypeRepresentationGenerator(compiler),
         classesNeedingRti = new Set<ClassElement>(),
+        methodsNeedingRti = new Set<Element>(),
         rtiDependencies = new Map<ClassElement, Set<ClassElement>>(),
         classesUsingTypeVariableExpression = new Set<ClassElement>();
 
@@ -77,7 +79,7 @@ class RuntimeTypes {
         InterfaceType interface = type;
         do {
           for (DartType argument in interface.typeArguments) {
-            universe.isChecks.add(argument);
+            universe.registerIsCheck(argument, compiler);
           }
           interface = interface.element.supertype;
         } while (interface != null && !instantiatedTypes.contains(interface));
@@ -100,7 +102,7 @@ class RuntimeTypes {
             InterfaceType instance = current.asInstanceOf(cls);
             if (instance == null) break;
             for (DartType argument in instance.typeArguments) {
-              universe.isChecks.add(argument);
+              universe.registerIsCheck(argument, compiler);
             }
             current = current.element.supertype;
           } while (current != null && !instantiatedTypes.contains(current));
@@ -162,11 +164,37 @@ class RuntimeTypes {
         if (!itf.isRaw) {
           potentiallyAddForRti(itf.element);
         }
-      } else if (type.kind == TypeKind.TYPE_VARIABLE) {
-        TypeVariableElement variable = type.element;
-        potentiallyAddForRti(variable.enclosingElement);
+      } else {
+        ClassElement contextClass = Types.getClassContext(type);

[karlklose, 2013/06/19 14:37:05]

I find it quite hard to follow this code because of getClassContext; it is not
clear what happens with type variables. Perhaps add a comment?

[Johnni Winther, 2013/06/21 12:19:15]

Done.

+        if (contextClass != null) {
+          potentiallyAddForRti(contextClass);
+        } else if (type.kind == TypeKind.FUNCTION) {
+          void analyzeMethod(Element method) {
+            DartType memberType = method.computeType(compiler);
+            contextClass = Types.getClassContext(memberType);
+            if (contextClass != null &&
+                compiler.types.isPotentialSubtype(memberType, type)) {
+              potentiallyAddForRti(contextClass);
+              methodsNeedingRti.add(method);
+            }
+          }
+          compiler.resolverWorld.closurizedGenericMembers.forEach(analyzeMethod);

[karlklose, 2013/06/19 14:37:05]

Long line.

[Johnni Winther, 2013/06/21 12:19:15]

Done.

+          compiler.resolverWorld.genericCallMethods.forEach(analyzeMethod);
+        }
       }
     });
+    if (compiler.enableTypeAssertions) {
+      void analyzeMethod(Element method) {
+        DartType memberType = method.computeType(compiler);
+        ClassElement contextClass = Types.getClassContext(memberType);
+        if (contextClass != null) {
+          potentiallyAddForRti(contextClass);
+          methodsNeedingRti.add(method);
+        }
+      }
+      compiler.resolverWorld.closurizedGenericMembers.forEach(analyzeMethod);
+      compiler.resolverWorld.genericCallMethods.forEach(analyzeMethod);
+    }
     // Add the classes that need RTI because they use a type variable as
     // expression.
     classesUsingTypeVariableExpression.forEach(potentiallyAddForRti);
@@ -210,12 +238,43 @@ class RuntimeTypes {
   }
 
   void computeRequiredChecks() {
-    computeInstantiatedArguments(compiler.codegenWorld);
-    computeCheckedArguments(compiler.codegenWorld);
+    Set<DartType> isChecks = compiler.codegenWorld.isChecks;
+    bool hasFunctionTypeCheck =
+        isChecks.any((type) => identical(type.kind, TypeKind.FUNCTION));
+    Set<DartType> instantiatedTypesAndClosures = hasFunctionTypeCheck
+        ? computeInstantiatedTypesAndClosures(compiler.codegenWorld)
+        : compiler.codegenWorld.instantiatedTypes;
+    computeInstantiatedArguments(instantiatedTypesAndClosures, isChecks);
+    computeCheckedArguments(instantiatedTypesAndClosures, isChecks);
     cachedRequiredChecks =
         computeChecks(allInstantiatedArguments, checkedArguments);
   }
 
+  Set<DartType> computeInstantiatedTypesAndClosures(Universe universe) {
+    Set<DartType> instantiatedTypes =
+        new Set<DartType>.from(universe.instantiatedTypes);
+    for (DartType instantiatedType in universe.instantiatedTypes) {
+      if (instantiatedType.kind == TypeKind.INTERFACE) {
+        Member member =
+            instantiatedType.lookupMember(Compiler.CALL_OPERATOR_NAME);
+        if (member != null) {
+          instantiatedTypes.add(member.computeType(compiler));
+        }
+      }
+    }
+    for (FunctionElement element in universe.staticFunctionsNeedingGetter) {
+      instantiatedTypes.add(element.computeType(compiler));
+    }
+    // TODO(johnniwinther): We should get this information through the
+    // [neededClasses] computed in the emitter instead of storing it and pulling
+    // it from resolution, but currently it would introduce a cyclic dependency
+    // between [computeRequiredChecks] and [computeNeededClasses].
+    for (Element element in compiler.resolverWorld.closurizedMembers) {
+      instantiatedTypes.add(element.computeType(compiler));
+    }
+    return instantiatedTypes;
+  }
+
   /**
    * Collects all types used in type arguments of instantiated types.
    *
@@ -223,14 +282,26 @@ class RuntimeTypes {
    * have a type check against this supertype that includes a check against
    * the type arguments.
    */
-  void computeInstantiatedArguments(Universe universe) {
+  void computeInstantiatedArguments(Set<DartType> instantiatedTypes,
+                                    Set<DartType> isChecks) {
     ArgumentCollector superCollector = new ArgumentCollector(backend);
     ArgumentCollector directCollector = new ArgumentCollector(backend);
-    for (DartType type in universe.instantiatedTypes) {
+    FunctionArgumentCollector functionArgumentCollector =
+        new FunctionArgumentCollector(backend);
+
+    // We need to add classes occuring in function type arguments, like for
+    // instance 'I' for [: o is C<f> :] where f is [: typedef I f(); :].
+    for (DartType type in isChecks) {
+      functionArgumentCollector.collect(type);
+    }
+
+    for (DartType type in instantiatedTypes) {
       directCollector.collect(type);
-      ClassElement cls = type.element;
-      for (DartType supertype in cls.allSupertypes) {
-        superCollector.collect(supertype);
+      if (type.kind == TypeKind.INTERFACE) {
+        ClassElement cls = type.element;
+        for (DartType supertype in cls.allSupertypes) {
+          superCollector.collect(supertype);
+        }
       }
     }
     for (ClassElement cls in superCollector.classes.toList()) {
@@ -238,18 +309,33 @@ class RuntimeTypes {
         superCollector.collect(supertype);
       }
     }
-    directlyInstantiatedArguments = directCollector.classes;
+
+    directlyInstantiatedArguments =
+        directCollector.classes..addAll(functionArgumentCollector.classes);
     allInstantiatedArguments =
         superCollector.classes..addAll(directlyInstantiatedArguments);
   }
 
   /// Collects all type arguments used in is-checks.
-  void computeCheckedArguments(Universe universe) {
+  void computeCheckedArguments(Set<DartType> instantiatedTypes,
+                               Set<DartType> isChecks) {
     ArgumentCollector collector = new ArgumentCollector(backend);
-    for (DartType type in universe.isChecks) {
+    FunctionArgumentCollector functionArgumentCollector =
+        new FunctionArgumentCollector(backend);
+
+    // We need to add types occuring in function type arguments, like for
+    // instance 'J' for [: (J j) {} is f :] where f is
+    // [: typedef void f(I i); :] and 'J' is a subtype of 'I'.
+    for (DartType type in instantiatedTypes) {
+      functionArgumentCollector.collect(type);
+    }
+
+    for (DartType type in isChecks) {
       collector.collect(type);
     }
-    checkedArguments = collector.classes;
+
+    checkedArguments =
+        collector.classes..addAll(functionArgumentCollector.classes);
   }
 
   Set<ClassElement> getClassesUsedInSubstitutions(JavaScriptBackend backend,
@@ -392,6 +478,41 @@ class RuntimeTypes {
     return '[$code]';
   }
 
+  String getTypeEncoding(DartType type,
+                         {bool alwaysGenerateFunction: false}) {
+    ClassElement contextClass = Types.getClassContext(type);
+    String onVariable(TypeVariableType v) {
+      return v.toString();
+    };
+    String encoding = _getTypeRepresentation(type, onVariable);
+    if (contextClass == null && !alwaysGenerateFunction) {
+      return encoding;
+    } else {
+      String parameters = contextClass != null
+          ? contextClass.typeVariables.toList().join(', ')
+          : '';
+      return 'function ($parameters) { return $encoding; }';
+    }
+  }
+
+  String getSignatureEncoding(DartType type, String generateThis()) {
+    ClassElement contextClass = Types.getClassContext(type);
+    String encoding = getTypeEncoding(type, alwaysGenerateFunction: true);
+    if (contextClass != null) {
+      String this_ = generateThis();
+      JavaScriptBackend backend = compiler.backend;
+      String applySignature =
+          backend.namer.getName(backend.getApplySignature());
+      String contextName = backend.namer.getName(contextClass);
+      return 'function () {'
+             ' return ${backend.namer.SETUP_OBJECT}.'
+                  '$applySignature($encoding, $this_, "$contextName"); '
+             '}';
+    } else {
+      return encoding;
+    }
+  }
+
   String getTypeRepresentation(DartType type, void onVariable(variable)) {
     // Create a type representation.  For type variables call the original
     // callback for side effects and return a template placeholder.
@@ -432,6 +553,9 @@ class TypeRepresentationGenerator extends DartTypeVisitor {
   OnVariableCallback onVariable;
   StringBuffer builder;
 
+  JavaScriptBackend get backend => compiler.backend;
+  Namer get namer => backend.namer;
+
   TypeRepresentationGenerator(Compiler this.compiler);
 
   /**
@@ -449,8 +573,6 @@ class TypeRepresentationGenerator extends DartTypeVisitor {
   }
 
   String getJsName(Element element) {
-    JavaScriptBackend backend = compiler.backend;
-    Namer namer = backend.namer;
     return namer.isolateAccess(backend.getImplementationClass(element));
   }
 
@@ -491,25 +613,26 @@ class TypeRepresentationGenerator extends DartTypeVisitor {
   }
 
   visitFunctionType(FunctionType type, _) {
-    builder.write('{func: true');
+    builder.write('{${namer.functionTypeTag()}:'
+                  ' "${namer.getFunctionTypeName(type)}"');
     if (type.returnType.isVoid) {
-      builder.write(', retvoid: true');
+      builder.write(', ${namer.functionTypeVoidReturnTag()}: true');
     } else if (!type.returnType.isDynamic) {
-      builder.write(', ret: ');
+      builder.write(', ${namer.functionTypeReturnTypeTag()}: ');
       visit(type.returnType);
     }
     if (!type.parameterTypes.isEmpty) {
-      builder.write(', args: [');
+      builder.write(', ${namer.functionTypeRequiredParametersTag()}: [');
       visitList(type.parameterTypes);
       builder.write(']');
     }
     if (!type.optionalParameterTypes.isEmpty) {
-      builder.write(', opt: [');
+      builder.write(', ${namer.functionTypeOptionalParametersTag()}: [');
       visitList(type.optionalParameterTypes);
       builder.write(']');
     }
     if (!type.namedParameterTypes.isEmpty) {
-      builder.write(', named: {');
+      builder.write(', ${namer.functionTypeNamedParametersTag()}: {');
       bool first = true;
       Link<SourceString> names = type.namedParameters;
       Link<DartType> types = type.namedParameterTypes;
@@ -529,8 +652,13 @@ class TypeRepresentationGenerator extends DartTypeVisitor {
     builder.write('}');
   }
 
+  visitMalformedType(MalformedType type, _) {
+    // Treat malformed types as dynamic at runtime.
+    builder.write('null');
+  }
+
   visitType(DartType type, _) {
-    compiler.internalError('Unexpected type: $type');
+    compiler.internalError('Unexpected type: $type (${type.kind})');
   }
 }
 
@@ -589,6 +717,10 @@ class ArgumentCollector extends DartTypeVisitor {
     // Do not collect [:dynamic:].
   }
 
+  visitTypedefType(TypedefType type, bool isTypeArgument) {
+    type.unalias(backend.compiler).accept(this, isTypeArgument);
+  }
+
   visitInterfaceType(InterfaceType type, bool isTypeArgument) {
     if (isTypeArgument) {
       classes.add(backend.getImplementationClass(type.element));
@@ -601,6 +733,48 @@ class ArgumentCollector extends DartTypeVisitor {
   }
 }
 
+class FunctionArgumentCollector extends DartTypeVisitor {
+  final JavaScriptBackend backend;
+  final Set<ClassElement> classes = new Set<ClassElement>();
+
+  FunctionArgumentCollector(this.backend);
+
+  collect(DartType type) {
+    type.accept(this, false);
+  }
+
+  /// Collect all types in the list as if they were arguments of an
+  /// InterfaceType.
+  collectAll(Link<DartType> types) {
+    for (Link<DartType> link = types; !link.isEmpty; link = link.tail) {
+      link.head.accept(this, true);
+    }
+  }
+
+  visitType(DartType type, _) {
+    // Do nothing.
+  }
+
+  visitDynamicType(DynamicType type, _) {
+    // Do not collect [:dynamic:].
+  }
+
+  visitTypedefType(TypedefType type, bool inFunctionType) {
+    type.unalias(backend.compiler).accept(this, inFunctionType);
+  }
+
+  visitInterfaceType(InterfaceType type, bool inFunctionType) {
+    if (inFunctionType) {
+      classes.add(backend.getImplementationClass(type.element));
+    }
+    type.visitChildren(this, inFunctionType);
+  }
+
+  visitFunctionType(FunctionType type, _) {
+    type.visitChildren(this, true);
+  }
+}
+
 /**
  * Representation of the substitution of type arguments
  * when going from the type of a class to one of its supertypes.
@@ -632,7 +806,7 @@ class Substitution {
       String formals = parameters.toList().map(variableName).join(', ');
       return 'function ($formals) { return $code; }';
     } else if (ensureIsFunction) {
-      return 'function() { return $code; }';
+      return 'function () { return $code; }';
     } else {
       return code;
     }