Generate tear-off closures dynamically.

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

Index: dart/sdk/lib/_internal/compiler/implementation/js_emitter/reflection_data_parser.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/js_emitter/reflection_data_parser.dart b/dart/sdk/lib/_internal/compiler/implementation/js_emitter/reflection_data_parser.dart
index 864f130d9538c355200697d8855360af580ec988..2e218f5accfd48bb3aba605b632e8c5631f49e55 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/js_emitter/reflection_data_parser.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/js_emitter/reflection_data_parser.dart
@@ -4,21 +4,183 @@
 
 part of dart2js.js_emitter;
 
+// TODO(ahe): Share these with js_helper.dart.
+const FUNCTION_INDEX = 0;
+const NAME_INDEX = 1;
+const CALL_NAME_INDEX = 2;
+const REQUIRED_PARAMETER_INDEX = 3;
+const OPTIONAL_PARAMETER_INDEX = 4;
+const DEFAULT_ARGUMENTS_INDEX = 5;
+
 // TODO(ahe): This code should be integrated in CodeEmitterTask.finishClasses.
-String getReflectionDataParser(String classesCollector, Namer namer) {
+String getReflectionDataParser(String classesCollector,
+                               JavaScriptBackend backend) {
+  Namer namer = backend.namer;
+  Compiler compiler = backend.compiler;
+  Element closureFromTearOff = compiler.findHelper('closureFromTearOff');
+  String tearOff =
+      // Default value for mocked-up test libraries.
+      'function () { throw "Helper \'closureFromTearOff\' missing." }';
+  if (closureFromTearOff != null) {
+    tearOff = namer.isolateAccess(closureFromTearOff);
+  }
   String metadataField = '"${namer.metadataField}"';
   String reflectableField = namer.reflectableField;
+  String reflectionInfoField = r'$reflectionInfo'; // MOVE TO NAMER

[Johnni Winther, 2013/12/05 11:49:56]

Add TODO for the comments.

[ahe, 2013/12/06 15:57:54]

Done.

+  String reflectionNameField = r'$reflectionName'; // DITTO
+  String metadataIndexField = r'$metadataIndex'; // DITTO
   String defaultValuesField = namer.defaultValuesField;
   String methodsWithOptionalArgumentsField =
       namer.methodsWithOptionalArgumentsField;
   return '''
 (function (reflectionData) {
+  "use strict";
 '''
 // [map] returns an object literal that V8 shouldn't try to optimize with a
 // hidden class. This prevents a potential performance problem where V8 tries
 // to build a hidden class for an object used as a hashMap.
 '''
   function map(x){x={x:x};delete x.x;return x}
+  function processStatics(descriptor) {
+    for (var property in descriptor) {
+      if (!hasOwnProperty.call(descriptor, property)) continue;
+      if (property === "") continue;
+      var element = descriptor[property];
+      var firstChar = property.substring(0, 1);
+      var previousProperty;
+      if (firstChar === "+") {

[Johnni Winther, 2013/12/05 11:49:56]

It would be nice to have a comment that gives an example of the descriptor
element and the resulting modifications. For instance: If the descriptor
contains
  'foo': function ...,
  '+bar': 1,
we will set 
  mangledGlobalNames['foo'] = 'bar'
and
  descriptor['foo']['$reflectable'] = 1.

Similarly for the cases below.

[ahe, 2013/12/06 15:57:54]

https://code.google.com/p/dart/issues/detail?id=15492

+        mangledGlobalNames[previousProperty] = property.substring(1);
+        if (descriptor[property] == 1) ''' // Break long line.
+'''descriptor[previousProperty].$reflectableField = 1;

[Johnni Winther, 2013/12/05 11:49:56]

Indent so `descriptor[previousProperty]` is below ` (descriptor[property]` to
make it more readable.

[ahe, 2013/12/06 15:57:54]

Done.

+        if (element && element.length) ''' // Break long line.
+'''init.typeInformation[previousProperty] = element;

[Johnni Winther, 2013/12/05 11:49:56]

Ditto.

[ahe, 2013/12/06 15:57:54]

Done.

+      } else if (firstChar === "@") {
+        property = property.substring(1);
+        ${namer.currentIsolate}[property][$metadataField] = element;
+      } else if (firstChar === "*") {
+        globalObject[previousProperty].$defaultValuesField = element;
+        var optionalMethods = descriptor.$methodsWithOptionalArgumentsField;
+        if (!optionalMethods) {
+          descriptor.$methodsWithOptionalArgumentsField = optionalMethods = {}
+        }
+        optionalMethods[property] = previousProperty;
+      } else if (typeof element === "function") {
+        globalObject[previousProperty = property] = element;
+        functions.push(property);
+        init.globalFunctions[property] = element;
+      } else if (element.constructor === Array) {
+        addStubs(globalObject, element, property, true, descriptor, functions);
+      } else {
+        previousProperty = property;
+        var newDesc = {};
+        var previousProp;
+        for (var prop in element) {
+          if (!hasOwnProperty.call(element, prop)) continue;
+          firstChar = prop.substring(0, 1);
+          if (prop === "static") {
+            processStatics(init.statics[property] = element[prop]);
+          } else if (firstChar === "+") {
+            mangledNames[previousProp] = prop.substring(1);
+            if (element[prop] == 1) ''' // Break long line.
+'''element[previousProp].$reflectableField = 1;

[Johnni Winther, 2013/12/05 11:49:56]

Ditto.

[ahe, 2013/12/06 15:57:54]

Done.

+          } else if (firstChar === "@" && prop !== "@") {
+            newDesc[prop.substring(1)][$metadataField] = element[prop];
+          } else if (firstChar === "*") {
+            newDesc[previousProp].$defaultValuesField = element[prop];
+            var optionalMethods = newDesc.$methodsWithOptionalArgumentsField;
+            if (!optionalMethods) {
+              newDesc.$methodsWithOptionalArgumentsField = optionalMethods={}
+            }
+            optionalMethods[prop] = previousProp;
+          } else {
+            var elem = element[prop];
+            if (prop && elem != null && elem.constructor === Array && prop !== "<>") {

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+              addStubs(newDesc, elem, prop, false, element, []);
+            } else {
+              newDesc[previousProp = prop] = elem;
+            }
+          }
+        }
+        $classesCollector[property] = [globalObject, newDesc];
+        classes.push(property);
+      }
+    }
+  }${
+  /**
+   * See [dart2js.js_emitter.ContainerBuilder.addMemberMethod] for format of
+   * [array].
+   */ ""}
+  function addStubs(descriptor, array, name, isStatic, originalDescriptor, functions) {

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+    var f, funcs = [originalDescriptor[name] = descriptor[name] = f = ${readFunction("array", "$FUNCTION_INDEX")}];

[Johnni Winther, 2013/12/05 11:49:56]

Ditto.

[ahe, 2013/12/06 15:57:54]

Done.

+    f.\$stubName = name;
+    functions.push(name);
+    for (var index = $FUNCTION_INDEX; index < array.length; index += 2) {
+      f = array[index + 1];
+      if (typeof f != "function") break;
+      f.\$stubName = ${readString("array", "index + 2")};
+      funcs.push(f);
+      // print("Stub for " + name + ": " + f.\$stubName);

[Johnni Winther, 2013/12/05 11:49:56]

Remove debug code.

[ahe, 2013/12/06 15:57:54]

Done.

+      if (f.\$stubName) {
+        originalDescriptor[f.\$stubName] = descriptor[f.\$stubName] = f;
+        functions.push(f.\$stubName);
+      }
+    }
+    for (var i = 0; i < funcs.length; index++, i++) {
+      funcs[i].\$callName = ${readString("array", "index + 1")};
+    }
+    var getterStubName = ${readString("array", "++index")};
+    array = array.slice(++index);
+    var requiredParameterInfo = ${readInt("array", "0")};
+    var requiredParameterCount = requiredParameterInfo >> 1;
+    var isAccessor = (requiredParameterInfo & 1) === 1;
+    var isSetter = requiredParameterInfo === 3;
+    var isGetter = requiredParameterInfo === 1;
+    var optionalParameterInfo = ${readInt("array", "1")};
+    var optionalParameterCount = optionalParameterInfo >> 1;
+    var optionalParametersAreNamed = (optionalParameterInfo & 1) === 1;
+    var functionTypeIndex = ${readFunctionType("array", "2")};
+    var isReflectable = array.length > optionalParameterCount + 3;
+    if (getterStubName) {
+      f = tearOff(funcs, array, isStatic, name);${

[Johnni Winther, 2013/12/05 11:49:56]

Replace ${ /* ... */ ""} by ''' // ... '''.

[ahe, 2013/12/06 15:57:54]

OK, but I don't think the code is more readable (or the generated output
suffers).

+      /* Used to create an isolate using spawnFunction.*/ ""}
+      if (isStatic) init.globalFunctions[name] = f;
+      originalDescriptor[getterStubName] = descriptor[getterStubName] = f;
+      funcs.push(f);
+      if (getterStubName) functions.push(getterStubName);
+      f.\$stubName = getterStubName;
+      f.\$callName = null;
+    }
+    if (isReflectable) {
+      for (var i = 0; i < funcs.length; i++) {
+        funcs[i].$reflectableField = 1;
+        funcs[i].$reflectionInfoField = array;
+      }
+    }
+    if (isReflectable) {
+      var unmangledNameIndex = optionalParameterCount * 2 + requiredParameterCount + 3;

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+      var unmangledName = ${readString("array", "unmangledNameIndex")};
+      var reflectionName = unmangledName + ":" + requiredParameterCount + ":" + optionalParameterCount;

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+      if (isGetter) {
+        reflectionName = unmangledName;
+      } else if (isSetter) {
+        reflectionName = unmangledName + "=";
+      }
+      if (isStatic) {
+        init.mangledGlobalNames[name] = reflectionName;
+      } else {
+        init.mangledNames[name] = reflectionName;
+      }
+      // print(name + " is reflectable with reflection name \'" + reflectionName + "\' " + isStatic);

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+      funcs[0].$reflectionNameField = reflectionName;
+      funcs[0].$metadataIndexField = unmangledNameIndex + 1;
+      if (optionalParameterCount) descriptor[unmangledName + "*"] = funcs[0];
+    }
+  }
+  function tearOff(funcs, reflectionInfo, isStatic, name) {
+    return function() {
+      return $tearOff(this, funcs, reflectionInfo, isStatic, arguments, name);
+    }
+  }
   if (!init.libraries) init.libraries = [];
   if (!init.mangledNames) init.mangledNames = map();
   if (!init.mangledGlobalNames) init.mangledGlobalNames = map();
@@ -53,67 +215,45 @@ String getReflectionDataParser(String classesCollector, Namer namer) {
     var fields = descriptor && descriptor[""];
     var classes = [];
     var functions = [];
-    function processStatics(descriptor) {
-      for (var property in descriptor) {
-        if (!hasOwnProperty.call(descriptor, property)) continue;
-        if (property === "") continue;
-        var element = descriptor[property];
-        var firstChar = property.substring(0, 1);
-        var previousProperty;
-        if (firstChar === "+") {
-          mangledGlobalNames[previousProperty] = property.substring(1);
-          if (descriptor[property] == 1) ''' // Break long line.
-'''descriptor[previousProperty].$reflectableField = 1;
-          if (element && element.length) ''' // Break long line.
-'''init.typeInformation[previousProperty] = element;
-        } else if (firstChar === "@") {
-          property = property.substring(1);
-          ${namer.currentIsolate}[property][$metadataField] = element;
-        } else if (firstChar === "*") {
-          globalObject[previousProperty].$defaultValuesField = element;
-          var optionalMethods = descriptor.$methodsWithOptionalArgumentsField;
-          if (!optionalMethods) {
-            descriptor.$methodsWithOptionalArgumentsField = optionalMethods = {}
-          }
-          optionalMethods[property] = previousProperty;
-        } else if (typeof element === "function") {
-          globalObject[previousProperty = property] = element;
-          functions.push(property);
-          init.globalFunctions[property] = element;
-        } else {
-          previousProperty = property;
-          var newDesc = {};
-          var previousProp;
-          for (var prop in element) {
-            if (!hasOwnProperty.call(element, prop)) continue;
-            firstChar = prop.substring(0, 1);
-            if (prop === "static") {
-              processStatics(init.statics[property] = element[prop]);
-            } else if (firstChar === "+") {
-              mangledNames[previousProp] = prop.substring(1);
-              if (element[prop] == 1) ''' // Break long line.
-'''element[previousProp].$reflectableField = 1;
-            } else if (firstChar === "@" && prop !== "@") {
-              newDesc[prop.substring(1)][$metadataField] = element[prop];
-            } else if (firstChar === "*") {
-              newDesc[previousProp].$defaultValuesField = element[prop];
-              var optionalMethods = newDesc.$methodsWithOptionalArgumentsField;
-              if (!optionalMethods) {
-                newDesc.$methodsWithOptionalArgumentsField = optionalMethods={}
-              }
-              optionalMethods[prop] = previousProp;
-            } else {
-              newDesc[previousProp = prop] = element[prop];
-            }
-          }
-          $classesCollector[property] = [globalObject, newDesc];
-          classes.push(property);
-        }
-      }
-    }
     processStatics(descriptor);
     libraries.push([name, uri, classes, functions, metadata, fields, isRoot,
                     globalObject]);
   }
 })''';
 }
+
+String readString(String array, String index) {
+  return readChecked(
+      array, index, 'result != null && typeof result != "string"', 'string');
+}
+
+String readInt(String array, String index) {
+  return readChecked(
+      array, index, 'result != null && (typeof result != "number" || (result|0) !== result)',

[Johnni Winther, 2013/12/05 11:49:56]

Long line.

[ahe, 2013/12/06 15:57:54]

Done.

+      'int');
+}
+
+String readFunction(String array, String index) {
+  return readChecked(
+      array, index, 'result != null && typeof result != "function"',
+      'function');
+}
+
+String readFunctionType(String array, String index) {
+  return readChecked(
+      array, index, 'result != null && (typeof result != "number" || (result|0) !== result) && typeof result != "function"',

[Johnni Winther, 2013/12/05 11:49:56]

Ditto.

[ahe, 2013/12/06 15:57:54]

Done.

+      'function or int');
+}
+
+String readChecked(String array, String index, String check, String type) {
+  return '''
+(function() {

[Johnni Winther, 2013/12/05 11:49:56]

Only return an applied function in checked mode?

[ahe, 2013/12/06 15:57:54]

Done.

+  var result = $array[$index];
+  if ($check) {
+    throw new Error(
+        name + ": expected value of type \'$type\' at index " + ($index) +
+        " but got " + (typeof result));
+  }
+  return result;
+})()''';
+}