Revert minification

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

 // Copyright (c) 2011, 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 js_backend;
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class Namer {
+  final Compiler compiler;
+
   static Set<String> _jsReserved = null;
   Set<String> get jsReserved {
     if (_jsReserved == null) {
       _jsReserved = new Set<String>();
       _jsReserved.addAll(JsNames.javaScriptKeywords);
       _jsReserved.addAll(JsNames.reservedPropertySymbols);
     }
     return _jsReserved;
   }
 
-  final String CURRENT_ISOLATE = r'$';
-
   /**
    * Map from top-level or static elements to their unique identifiers provided
    * by [getName].
    *
    * Invariant: Keys must be declaration elements.
    */
-  final Compiler compiler;
   final Map<Element, String> globals;
+  final Map<String, int> usedGlobals;
   final Map<String, LibraryElement> shortPrivateNameOwners;
-  final Set<String> usedGlobalNames;
-  final Set<String> usedInstanceNames;
-  final Map<String, String> instanceNameMap;
-  final Map<String, String> globalNameMap;
-  final Map<String, int> popularNameCounters;
 
   /**
    * A cache of names used for bailout methods. We make sure two
    * bailout methods cannot have the same name because if the two
    * bailout methods are in a class and a subclass, we would
    * call the wrong bailout method at runtime. To make it
    * simple, we don't keep track of inheritance and always avoid
    * similar names.
    */
   final Set<String> usedBailoutInstanceNames;
   final Map<Element, String> bailoutNames;
 
   final Map<Constant, String> constantNames;
 
   Namer(this.compiler)
       : globals = new Map<Element, String>(),
+        usedGlobals = new Map<String, int>(),
         shortPrivateNameOwners = new Map<String, LibraryElement>(),
         bailoutNames = new Map<Element, String>(),
         usedBailoutInstanceNames = new Set<String>(),
-        usedGlobalNames = new Set<String>(),
-        usedInstanceNames = new Set<String>(),
-        instanceNameMap = new Map<String, String>(),
-        globalNameMap = new Map<String, String>(),
-        constantNames = new Map<Constant, String>(),
-        popularNameCounters = new Map<String, int>();
+        constantNames = new Map<Constant, String>();
 
-  String get isolateName => 'Isolate';
-  String get isolatePropertiesName => r'$isolateProperties';
+  final String CURRENT_ISOLATE = r'$';
+  final String ISOLATE = 'Isolate';
+  final String ISOLATE_PROPERTIES = r"$isolateProperties";
   /**
    * Some closures must contain their name. The name is stored in
    * [STATIC_CLOSURE_NAME_NAME].
    */
-  String get STATIC_CLOSURE_NAME_NAME => r'$name';
-  SourceString get closureInvocationSelector => Compiler.CALL_OPERATOR_NAME;
-  bool get shouldMinify => false;
-
-  bool isReserved(String name) => name == isolateName;
+  final String STATIC_CLOSURE_NAME_NAME = r'$name';
+  static const SourceString CLOSURE_INVOCATION_NAME =
+      Compiler.CALL_OPERATOR_NAME;
 
   String constantName(Constant constant) {
     // In the current implementation it doesn't make sense to give names to
     // function constants since the function-implementation itself serves as
     // constant and can be accessed directly.
     assert(!constant.isFunction());
     String result = constantNames[constant];
     if (result == null) {
-      String longName;
-      if (shouldMinify) {
-        if (constant.isString()) {
-          StringConstant stringConstant = constant;
-          // The minifier always constructs a new name, using the argument as
-          // input to its hashing algorithm.  The given name does not need to be
-          // valid.
-          longName = stringConstant.value.slowToString();
-        } else {
-          longName = "C";
-        }
-      } else {
-        longName = "CONSTANT";
-      }
-      result = getFreshName(longName, usedGlobalNames);
+      result = getFreshGlobalName("CTC");
       constantNames[constant] = result;
     }
     return result;
   }
 
   String closureInvocationName(Selector selector) {
-    return
-        instanceMethodInvocationName(null, closureInvocationSelector, selector);
+    // TODO(floitsch): mangle, while not conflicting with instance names.
+    return instanceMethodInvocationName(null, CLOSURE_INVOCATION_NAME,
+                                        selector);
   }
 
   String breakLabelName(LabelElement label) {
     return '\$${label.labelName}\$${label.target.nestingLevel}';
   }
 
   String implicitBreakLabelName(TargetElement target) {
     return '\$${target.nestingLevel}';
   }
 
   // We sometimes handle continue targets differently from break targets,
   // so we have special continue-only labels.
   String continueLabelName(LabelElement label) {
     return 'c\$${label.labelName}\$${label.target.nestingLevel}';
   }
 
   String implicitContinueLabelName(TargetElement target) {
     return 'c\$${target.nestingLevel}';
   }
 
   /**
    * If the [name] is not private returns [:name.slowToString():]. Otherwise
    * mangles the [name] so that each library has a unique name.
    */
   String privateName(LibraryElement lib, SourceString name) {
-    String result;
     if (name.isPrivate()) {
       String nameString = name.slowToString();
       // The first library asking for a short private name wins.
-      LibraryElement owner = shouldMinify ?
-          lib :
+      LibraryElement owner =
           shortPrivateNameOwners.putIfAbsent(nameString, () => lib);
       // If a private name could clash with a mangled private name we don't
       // use the short name. For example a private name "_lib3_foo" would
       // clash with "_foo" from "lib3".
-      if (owner == lib &&
-          !nameString.startsWith('_$LIBRARY_PREFIX') &&
-          !shouldMinify) {
-        result = nameString;
-      } else {
-        String libName = getName(lib);
-        // If a library name does not start with the [LIBRARY_PREFIX] then our
-        // assumptions about clashing with mangled private members do not hold.
-        assert(shouldMinify || libName.startsWith(LIBRARY_PREFIX));
-        // TODO(erikcorry): Fix this with other manglings to avoid clashes.
-        result = '_lib$libName\$$nameString';
+      if (identical(owner, lib) && !nameString.startsWith('_$LIBRARY_PREFIX')) {
+        return nameString;
       }
+      String libName = getName(lib);
+      // If a library name does not start with the [LIBRARY_PREFIX] then our
+      // assumptions about clashing with mangled private members do not hold.
+      assert(libName.startsWith(LIBRARY_PREFIX));
+      return '_$libName$nameString';
     } else {
-      result = name.slowToString();
+      return name.slowToString();
     }
-    return result;
   }
 
   String instanceMethodName(FunctionElement element) {
     SourceString name = Elements.operatorNameToIdentifier(element.name);
     LibraryElement lib = element.getLibrary();
     if (element.kind == ElementKind.GENERATIVE_CONSTRUCTOR_BODY) {
       ConstructorBodyElement bodyElement = element;
       name = bodyElement.constructor.name;
     }
     FunctionSignature signature = element.computeSignature(compiler);
     String methodName =
         '${privateName(lib, name)}\$${signature.parameterCount}';
-    if (signature.optionalParametersAreNamed &&
-        !signature.optionalParameters.isEmpty) {
+    if (!signature.optionalParametersAreNamed) {
+      return methodName;
+    } else if (!signature.optionalParameters.isEmpty) {
       StringBuffer buffer = new StringBuffer();
       signature.orderedOptionalParameters.forEach((Element element) {
         buffer.add('\$${JsNames.getValid(element.name.slowToString())}');
       });
-      methodName = '$methodName$buffer';
+      return '$methodName$buffer';
     }
-    if (name == closureInvocationSelector) return methodName;
-    return getMappedInstanceName(methodName);
   }
 
   String publicInstanceMethodNameByArity(SourceString name, int arity) {
     name = Elements.operatorNameToIdentifier(name);
     assert(!name.isPrivate());
-    var base = name.slowToString();
-    // We don't mangle the closure invoking function name because it is
-    // generated in applyFunction.
-    var proposedName = '$base\$$arity';
-    if (base == closureInvocationSelector) return proposedName;
-    return getMappedInstanceName(proposedName);
+    return '${name.slowToString()}\$$arity';
   }
 
   String instanceMethodInvocationName(LibraryElement lib, SourceString name,
                                       Selector selector) {
     name = Elements.operatorNameToIdentifier(name);
     // TODO(floitsch): mangle, while preserving uniqueness.
     StringBuffer buffer = new StringBuffer();
     List<SourceString> names = selector.getOrderedNamedArguments();
     for (SourceString argumentName in names) {
       buffer.add(r'$');
       argumentName.printOn(buffer);
     }
-    if (name == closureInvocationSelector) {
-      // We don't mangle the closure invoking function name because it is
-      // generated in applyFunction.
-      return '$closureInvocationSelector\$${selector.argumentCount}$buffer';
-    }
-    return getMappedInstanceName(
-        '${privateName(lib, name)}\$${selector.argumentCount}$buffer');
+    return '${privateName(lib, name)}\$${selector.argumentCount}$buffer';
   }
 
   String instanceFieldName(LibraryElement libraryElement, SourceString name) {
     String proposedName = privateName(libraryElement, name);
-    return getMappedInstanceName(proposedName);
+    return safeName(proposedName);
   }
 
-  // Construct a new name for the element based on the library and class it is
-  // in.  The name here is not important, we just need to make sure it is
-  // unique.  If we are minifying, we actually construct the name from the
-  // minified versions of the class and instance names, but the result is
-  // minified once again, so that is not visible in the end result.
   String shadowedFieldName(Element fieldElement) {
-    // Check for following situation: Native field ${fieldElement.name} has
-    // fixed JSName ${fieldElement.nativeName()}, but a subclass shadows this
-    // name.  We normally handle that by renaming the superclass field, but we
-    // can't do that because native fields have fixed JSNames.  In practice
-    // this can't happen because we can't inherit from native classes.
-    assert (!fieldElement.isNative());
-
     ClassElement cls = fieldElement.getEnclosingClass();
     LibraryElement libraryElement = fieldElement.getLibrary();
     String libName = getName(libraryElement);
     String clsName = getName(cls);
     String instanceName = instanceFieldName(libraryElement, fieldElement.name);
-    return getMappedInstanceName('$libName\$$clsName\$$instanceName');
+    return safeName('$libName\$$clsName\$$instanceName');
   }
 
   String setterName(LibraryElement lib, SourceString name) {
     // We dynamically create setters from the field-name. The setter name must
     // therefore be derived from the instance field-name.
-    String fieldName = getMappedInstanceName(privateName(lib, name));
+    String fieldName = safeName(privateName(lib, name));
     return 'set\$$fieldName';
   }
 
-  String setterNameFromAccessorName(String name) {
-    // We dynamically create setters from the field-name. The setter name must
-    // therefore be derived from the instance field-name.
-    return 'set\$$name';
-  }
-
   String publicGetterName(SourceString name) {
     // We dynamically create getters from the field-name. The getter name must
     // therefore be derived from the instance field-name.
-    String fieldName = getMappedInstanceName(name.slowToString());
+    String fieldName = safeName(name.slowToString());
     return 'get\$$fieldName';
   }
 
-  String getterNameFromAccessorName(String name) {
-    // We dynamically create getters from the field-name. The getter name must
-    // therefore be derived from the instance field-name.
-    return 'get\$$name';
-  }
-
   String getterName(LibraryElement lib, SourceString name) {
     // We dynamically create getters from the field-name. The getter name must
     // therefore be derived from the instance field-name.
-    String fieldName = getMappedInstanceName(privateName(lib, name));
+    String fieldName = safeName(privateName(lib, name));
     return 'get\$$fieldName';
   }
 
-  String getMappedGlobalName(String proposedName) {
-    var newName = globalNameMap[proposedName];
-    if (newName == null) {
-      newName = getFreshName(proposedName, usedGlobalNames);
-      globalNameMap[proposedName] = newName;
+  String getFreshGlobalName(String proposedName) {
+    String name = proposedName;
+    int count = usedGlobals[name];
+    if (count != null) {
+      // Not the first time we see this name. Append a number to make it unique.
+      do {
+        name = '$proposedName${count++}';
+      } while (usedGlobals[name] != null);
+      // Record the count in case we see this name later. We
+      // frequently see names multiple times, as all our closures use
+      // the same name for their class.
+      usedGlobals[proposedName] = count;
     }
-    return newName;
-  }
-
-  String getMappedInstanceName(String proposedName) {
-    var newName = instanceNameMap[proposedName];
-    if (newName == null) {
-      newName = getFreshName(proposedName, usedInstanceNames);
-      instanceNameMap[proposedName] = newName;
-    }
-    return newName;
-  }
-
-  String getFreshName(String proposedName, Set<String> usedNames) {
-    var candidate;
-    proposedName = safeName(proposedName);
-    if (!usedNames.contains(proposedName)) {
-      candidate = proposedName;
-    } else {
-      var counter = popularNameCounters[proposedName];
-      var i = counter == null ? 0 : counter;
-      while (usedNames.contains("$proposedName$i")) {
-        i++;
-      }
-      popularNameCounters[proposedName] = i + 1;
-      candidate = "$proposedName$i";
-    }
-    usedNames.add(candidate);
-    return candidate;
+    usedGlobals[name] = 0;
+    return name;
   }
 
   static const String LIBRARY_PREFIX = "lib";
 
   /**
    * Returns a preferred JS-id for the given top-level or static element.
    * The returned id is guaranteed to be a valid JS-id.
    */
   String _computeGuess(Element element) {
     assert(!element.isInstanceMember());
@@ skipping 12 matching lines @@
         name = "${enclosingClass.name.slowToString()}_"
                "${element.name.slowToString()}";
       } else {
         name = element.name.slowToString();
       }
     } else if (element.isLibrary()) {
       name = LIBRARY_PREFIX;
     } else {
       name = element.name.slowToString();
     }
-    return name;
+    return safeName(name);
   }
 
   String getSpecializedName(Element element, Collection<ClassElement> classes) {
-    // This gets the minified name, but it doesn't really make much difference.
-    // the important thing is that it is a unique name.
     StringBuffer buffer = new StringBuffer('${getName(element)}\$');
     for (ClassElement cls in classes) {
       buffer.add(getName(cls));
     }
-    return getMappedGlobalName(buffer.toString());
+    return safeName(buffer.toString());
   }
 
   String getBailoutName(Element element) {
     String name = bailoutNames[element];
     if (name != null) return name;
     bool global = !element.isInstanceMember();
-    // Despite the name of the variable, this gets the minified name when we
-    // are minifying, but it doesn't really make much difference.  The
-    // important thing is that it is a unique name.  We add $bailout and, if we
-    // are minifying, we minify the minified name and '$bailout'.
     String unminifiedName = '${getName(element)}\$bailout';
-    if (global) {
-      name = getMappedGlobalName(unminifiedName);
-    } else {
-      name = unminifiedName;
+    name = unminifiedName;
+    if (!global) {
       int i = 0;
       while (usedBailoutInstanceNames.contains(name)) {
         name = '$unminifiedName${i++}';
       }
       usedBailoutInstanceNames.add(name);
-      name = getMappedInstanceName(name);
     }
     bailoutNames[element] = name;
     return name;
   }
 
   /**
    * Returns a preferred JS-id for the given element. The returned id is
    * guaranteed to be a valid JS-id. Globals and static fields are furthermore
    * guaranteed to be unique.
    *
@@ skipping 17 matching lines @@
       }
     } else {
       // Use declaration element to ensure invariant on [globals].
       element = element.declaration;
       // Dealing with a top-level or static element.
       String cached = globals[element];
       if (cached != null) return cached;
 
       String guess = _computeGuess(element);
       ElementKind kind = element.kind;
-      if (kind == ElementKind.VARIABLE ||
-          kind == ElementKind.PARAMETER) {
+      if (identical(kind, ElementKind.VARIABLE) ||
+          identical(kind, ElementKind.PARAMETER)) {
         // The name is not guaranteed to be unique.
-        return safeName(guess);
+        return guess;
       }
-      if (kind == ElementKind.GENERATIVE_CONSTRUCTOR ||
-          kind == ElementKind.FUNCTION ||
-          kind == ElementKind.CLASS ||
-          kind == ElementKind.FIELD ||
-          kind == ElementKind.GETTER ||
-          kind == ElementKind.SETTER ||
-          kind == ElementKind.TYPEDEF ||
-          kind == ElementKind.LIBRARY ||
-          kind == ElementKind.MALFORMED_TYPE) {
-        bool isNative = false;
-        if (kind == ElementKind.CLASS) {
-          ClassElement class_elt = element;
-          isNative = class_elt.isNative();
-        }
-        if (Elements.isInstanceField(element)) {
-          isNative = element.isNative();
-        }
-        String result = isNative ? guess : getFreshName(guess, usedGlobalNames);
+      if (identical(kind, ElementKind.GENERATIVE_CONSTRUCTOR) ||
+          identical(kind, ElementKind.FUNCTION) ||
+          identical(kind, ElementKind.CLASS) ||
+          identical(kind, ElementKind.FIELD) ||
+          identical(kind, ElementKind.GETTER) ||
+          identical(kind, ElementKind.SETTER) ||
+          identical(kind, ElementKind.TYPEDEF) ||
+          identical(kind, ElementKind.LIBRARY) ||
+          identical(kind, ElementKind.MALFORMED_TYPE)) {
+        String result = getFreshGlobalName(guess);
         globals[element] = result;
         return result;
       }
       compiler.internalError('getName for unknown kind: ${element.kind}',
                               node: element.parseNode(compiler));
     }
   }
 
   String getLazyInitializerName(Element element) {
+    // TODO(floitsch): mangle while not conflicting with other statics.
     assert(Elements.isStaticOrTopLevelField(element));
-    return getMappedGlobalName("get\$${getName(element)}");
+    return "get\$${getName(element)}";
   }
 
   String isolatePropertiesAccess(Element element) {
-    return "$isolateName.$isolatePropertiesName.${getName(element)}";
+    return "$ISOLATE.$ISOLATE_PROPERTIES.${getName(element)}";
   }
 
   String isolateAccess(Element element) {
     return "$CURRENT_ISOLATE.${getName(element)}";
   }
 
   String isolateBailoutAccess(Element element) {
-    String newName = getMappedGlobalName('${getName(element)}\$bailout');
-    return '$CURRENT_ISOLATE.$newName';
+    return '${isolateAccess(element)}\$bailout';
   }
 
   String isolateLazyInitializerAccess(Element element) {
     return "$CURRENT_ISOLATE.${getLazyInitializerName(element)}";
   }
 
   String operatorIs(Element element) {
-    // TODO(erikcorry): Reduce from is$x to ix when we are minifying.
     return 'is\$${getName(element)}';
   }
 
   String safeName(String name) {
     if (jsReserved.contains(name) || name.startsWith('\$')) {
       name = "\$$name";
       assert(!jsReserved.contains(name));
     }
     return name;
   }
 }