Generate tear-off closures dynamically.

dart/sdk/lib/_internal/compiler/implementation/js_emitter/container_builder.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js.js_emitter;
 
 /// This class should morph into something that makes it easy to build
 /// JavaScript representations of libraries, class-sides, and instance-sides.
 /// Initially, it is just a placeholder for code that is moved from
 /// [CodeEmitterTask].
@@ skipping 111 matching lines @@
           parametersBuffer, argumentsBuffer,
           indexOfLastOptionalArgumentInParameters);
     } else {
       body = [js.return_(
           js('this')[namer.getNameOfInstanceMember(member)](argumentsBuffer))];
     }
 
     jsAst.Fun function = js.fun(parametersBuffer, body);
 
     defineStub(invocationName, function);
-
-    String reflectionName = task.getReflectionName(selector, invocationName);
-    if (reflectionName != null) {
-      var reflectable =
-          js(backend.isAccessibleByReflection(member) ? '1' : '0');
-      defineStub('+$reflectionName', reflectable);
-    }
   }
 
   void addParameterStubs(FunctionElement member,
                          DefineStubFunction defineStub) {
+    // Bound closures are generated dynamically.
+    if (member.enclosingElement.isClosure()) return;
+
     // We fill the lists depending on the selector. For example,
     // take method foo:
     //    foo(a, b, {c, d});
     //
     // We may have multiple ways of calling foo:
     // (1) foo(1, 2);
     // (2) foo(1, 2, c: 3);
     // (3) foo(1, 2, d: 4);
     // (4) foo(1, 2, c: 3, d: 4);
     // (5) foo(1, 2, d: 4, c: 3);
     //
     // What we generate at the call sites are:
     // (1) foo$2(1, 2);
     // (2) foo$3$c(1, 2, 3);
     // (3) foo$3$d(1, 2, 4);
     // (4) foo$4$c$d(1, 2, 3, 4);
     // (5) foo$4$c$d(1, 2, 3, 4);
     //
     // The stubs we generate are (expressed in Dart):
     // (1) foo$2(a, b) => foo$4$c$d(a, b, null, null)
     // (2) foo$3$c(a, b, c) => foo$4$c$d(a, b, c, null);
     // (3) foo$3$d(a, b, d) => foo$4$c$d(a, b, null, d);
     // (4) No stub generated, call is direct.
     // (5) No stub generated, call is direct.
 
     // Keep a cache of which stubs have already been generated, to
     // avoid duplicates. Note that even if selectors are
     // canonicalized, we would still need this cache: a typed selector
     // on A and a typed selector on B could yield the same stub.
-    Set<String> generatedStubNames = new Set<String>();
-    bool isClosureInvocation =
-        member.name == namer.closureInvocationSelectorName;
-    if (backend.isNeededForReflection(member) ||
-        (compiler.enabledFunctionApply && isClosureInvocation)) {
-      // If [Function.apply] is called, we pessimistically compile all
-      // possible stubs for this closure.
-      FunctionSignature signature = member.computeSignature(compiler);
-      Set<Selector> selectors = signature.optionalParametersAreNamed
-          ? computeSeenNamedSelectors(member)
-          : computeOptionalSelectors(signature, member);
-      for (Selector selector in selectors) {
-        addParameterStub(member, selector, defineStub, generatedStubNames);
+    Set<Selector> selectors = compiler.codegenWorld.invokedNames[member.name];
+    if (selectors == null) {
+      selectors = compiler.codegenWorld.invokedNames[
+          namer.closureInvocationSelectorName];

[kasperl, 2013/10/21 10:25:44]

Cache namer.closureInvocationSelectorName in a local?

[ahe, 2013/12/06 15:57:53]

The code is now so distant that I don't think it helps readability.

+      if (selectors == null) return;
+    } else {
+      Set<Selector> callSelectors = compiler.codegenWorld.invokedNames[
+          namer.closureInvocationSelectorName];
+      if (callSelectors != null) {
+        selectors = new Set<Selector>.from(selectors)..addAll(callSelectors);

[kasperl, 2013/10/21 10:25:44]

Can you use Set.union here?

[ahe, 2013/10/22 10:52:34]

Oh yeah! I didn't know about that method :-)

       }
-      if (signature.optionalParametersAreNamed && isClosureInvocation) {
-        addCatchAllParameterStub(member, signature, defineStub);
-      }
-    } else {
-      Set<Selector> selectors = compiler.codegenWorld.invokedNames[member.name];
-      if (selectors == null) return;
-      for (Selector selector in selectors) {
-        if (!selector.applies(member, compiler)) continue;
-        addParameterStub(member, selector, defineStub, generatedStubNames);
-      }
+    }
+    for (Selector selector in selectors) {
+      if (!selector.applies(member, compiler)) continue;
+      // TODO(ahe): Is the last argument to [addParameterStub] needed?
+      addParameterStub(member, selector, defineStub, new Set<String>());
     }
   }
 
-  Set<Selector> computeSeenNamedSelectors(FunctionElement element) {
-    Set<Selector> selectors = compiler.codegenWorld.invokedNames[element.name];
-    Set<Selector> result = new Set<Selector>();
-    if (selectors == null) return result;
-    for (Selector selector in selectors) {
-      if (!selector.applies(element, compiler)) continue;
-      result.add(selector);
-    }
-    return result;
-  }
-
-  void addCatchAllParameterStub(FunctionElement member,
-                                FunctionSignature signature,
-                                DefineStubFunction defineStub) {
-    // See Primities.applyFunction in js_helper.dart for details.
-    List<jsAst.Property> properties = <jsAst.Property>[];
-    for (Element element in signature.orderedOptionalParameters) {
-      String jsName = backend.namer.safeName(element.name.slowToString());
-      Constant value = compiler.constantHandler.initialVariableValues[element];
-      jsAst.Expression reference = null;
-      if (value == null) {
-        reference = new jsAst.LiteralNull();
-      } else {
-        reference = task.constantReference(value);
-      }
-      properties.add(new jsAst.Property(js.string(jsName), reference));
-    }
-    defineStub(
-        backend.namer.callCatchAllName,
-        js.fun([], js.return_(new jsAst.ObjectInitializer(properties))));
-  }
-
-  /**
-   * Compute the set of possible selectors in the presence of optional
-   * non-named parameters.
-   */
-  Set<Selector> computeOptionalSelectors(FunctionSignature signature,
-                                         FunctionElement element) {
-    Set<Selector> selectors = new Set<Selector>();
-    // Add the selector that does not have any optional argument.
-    selectors.add(new Selector(SelectorKind.CALL,
-                               element.name,
-                               element.getLibrary(),
-                               signature.requiredParameterCount,
-                               <SourceString>[]));
-
-    // For each optional parameter, we increment the number of passed
-    // argument.
-    for (int i = 1; i <= signature.optionalParameterCount; i++) {
-      selectors.add(new Selector(SelectorKind.CALL,
-                                 element.name,
-                                 element.getLibrary(),
-                                 signature.requiredParameterCount + i,
-                                 <SourceString>[]));
-    }
-    return selectors;
-  }
-
   void emitStaticFunctionGetters(CodeBuffer eagerBuffer) {
+    return;
     task.addComment('Static function getters', task.mainBuffer);
     for (FunctionElement element in
              Elements.sortedByPosition(staticGetters.keys)) {
       Element closure = staticGetters[element];
       CodeBuffer buffer =
           task.isDeferred(element) ? task.deferredConstants : eagerBuffer;
       String closureClass = namer.isolateAccess(closure);
       String name = namer.getStaticClosureName(element);
 
       String closureName = namer.getStaticClosureName(element);
@@ skipping 304 matching lines @@
    *
    * Invariant: [member] must be a declaration element.
    */
   void emitExtraAccessors(Element member, ClassBuilder builder) {
     assert(invariant(member, member.isDeclaration));
     if (member.isGetter() || member.isField()) {
       Set<Selector> selectors = compiler.codegenWorld.invokedNames[member.name];
       if (selectors != null && !selectors.isEmpty) {
         emitCallStubForGetter(member, selectors, builder.addProperty);
       }
-    } else if (member.isFunction()) {
-      if (compiler.codegenWorld.hasInvokedGetter(member, compiler)) {
-        emitDynamicFunctionGetter(member, builder.addProperty);
-      }
     }
   }
 
   void addMember(Element member, ClassBuilder builder) {
     assert(invariant(member, member.isDeclaration));
 
     if (member.isField()) {
       addMemberField(member, builder);
     } else if (member.isFunction() ||
                member.isGenerativeConstructorBody() ||
                member.isGenerativeConstructor() ||
                member.isAccessor()) {
       addMemberMethod(member, builder);
     } else {
       compiler.internalErrorOnElement(
           member, 'unexpected kind: "${member.kind}"');
     }
     if (member.isInstanceMember()) emitExtraAccessors(member, builder);
   }
 
   void addMemberMethod(FunctionElement member, ClassBuilder builder) {
     if (member.isAbstract(compiler)) return;
     jsAst.Expression code = backend.generatedCode[member];
     if (code == null) return;
     String name = namer.getNameOfMember(member);
-    if (backend.isInterceptedMethod(member)) {
-      task.interceptorEmitter.interceptorInvocationNames.add(name);
+    task.interceptorEmitter.recordMangledNameOfMemberMethod(member, name);
+    FunctionSignature parameters = member.computeSignature(compiler);
+    bool needsStubs = !parameters.optionalParameters.isEmpty;
+    bool canTearOff = false;

[kasperl, 2013/10/21 10:25:44]

Consider only using tearOffName (null could represent canTearOff = false). Not
sure if it's a good idea.

[ahe, 2013/12/06 15:57:53]

I forgot about this comment, but I'm weary of changing this logic until after
this CL has landed.

+    String tearOffName;
+    if (member.isInstanceMember()) {
+      // Careful with operators.
+      canTearOff = compiler.codegenWorld.hasInvokedGetter(member, compiler);
+      tearOffName = namer.getterName(member);
+    } else {
+      canTearOff =
+          compiler.codegenWorld.staticFunctionsNeedingGetter.contains(member);
+      tearOffName = namer.getStaticClosureName(member);
     }
-    code = task.metadataEmitter.extendWithMetadata(member, code);
-    builder.addProperty(name, code);
-    String reflectionName = task.getReflectionName(member, name);
-    if (reflectionName != null) {
-      var reflectable =
-          js(backend.isAccessibleByReflection(member) ? '1' : '0');
-      builder.addProperty('+$reflectionName', reflectable);
-      jsAst.Node defaultValues =
-          task.metadataEmitter.reifyDefaultArguments(member);
-      if (defaultValues != null) {
-        String unmangledName = member.name.slowToString();
-        builder.addProperty('*$unmangledName', defaultValues);
-      }
+
+    if (!canTearOff && !needsStubs && !backend.isNeededForReflection(member)) {
+      builder.addProperty(name, code);
+      addBailout(member, builder);
+      return;
     }
-    code = backend.generatedBailoutCode[member];
+    // This element is needed for reflection or needs additional stubs. So we
+    // need to retain additional information.
+
+    List expressions = [];
+
+    bool canBeReflected = backend.isAccessibleByReflection(member);
+    expressions
+        ..add(code)
+        ..add(member.isAccessor() ? js("null") : js.string(tearOffName))
+        // TODO(ahe): Obtain proper name.
+        ..add(js.string("call\$${parameters.requiredParameterCount}"))
+        ..add(canBeReflected ? parameters.requiredParameterCount + 1 : 0)
+        ..add(parameters.optionalParameterCount)
+        ..addAll(task.metadataEmitter.reifyDefaultArguments(member));
+
+    if (needsStubs) {
+      addParameterStubs(member, (String name, jsAst.Fun function) {
+        expressions.add(function);
+        expressions.add(js.string(name));
+        // TODO(ahe): Obtain proper call name.
+        expressions.add(js.string("call\$${function.params.length}"));
+      });
+    }
+
+    if (canBeReflected) {
+      expressions
+          ..add(js.string(member.name.slowToString()))
+          ..addAll(task.metadataEmitter.computeMetadata(member));
+    }
+
+    builder.addProperty(name, js.toExpression(expressions));
+
+    addBailout(member, builder);
+
+    // if (canTearOff) {
+    //   emitDynamicFunctionGetter(member, builder.addProperty);
+    // }
+  }
+
+  void addBailout(FunctionElement member, ClassBuilder builder) {
+    jsAst.Expression code = backend.generatedBailoutCode[member];
     if (code != null) {
       builder.addProperty(namer.getBailoutName(member), code);
     }
-    if (member.isInstanceMember()) {
-      // TODO(ahe): Where is this done for static/top-level methods?
-      FunctionSignature parameters = member.computeSignature(compiler);
-      if (!parameters.optionalParameters.isEmpty) {
-        addParameterStubs(member, builder.addProperty);
-      }
-    }
   }
 
   void addMemberField(VariableElement member, ClassBuilder builder) {
     // For now, do nothing.
   }
 }