/** Traverses a parse tree recursively with a scope, starting at that scope's root. */
  void traverseAtScope(Scope s) {
    Node n = s.getRootNode();
    if (n.isFunction()) {
      // We need to do some extra magic to make sure that the scope doesn't
      // get re-created when we dive into the function.
      if (inputId == null) {
        inputId = NodeUtil.getInputId(n);
      }
      sourceName = getSourceName(n);
      curNode = n;
      pushScope(s);

      Node args = n.getFirstChild().getNext();
      Node body = args.getNext();
      traverseBranch(args, n);
      traverseBranch(body, n);

      popScope();
    } else if (n.isBlock()) {
      if (inputId == null) {
        inputId = NodeUtil.getInputId(n);
      }
      sourceName = getSourceName(n);
      curNode = n;
      pushScope(s);
      traverseBranch(n, n.getParent());

      popScope();
    } else {
      Preconditions.checkState(s.isGlobal(), "Expected global scope. Got:", s);
      traverseWithScope(n, s);
    }
  }
  /**
   * @param fnName The name of this function. This either the name of the variable to which the
   *     function is assigned or the name from the FUNCTION node.
   * @param fnNode The FUNCTION node of the function to inspect.
   * @return Whether the function node meets the minimum requirements for inlining.
   */
  boolean doesFunctionMeetMinimumRequirements(final String fnName, Node fnNode) {
    Node block = NodeUtil.getFunctionBody(fnNode);

    // Basic restrictions on functions that can be inlined:
    // 1) It contains a reference to itself.
    // 2) It uses its parameters indirectly using "arguments" (it isn't
    //    handled yet.
    // 3) It references "eval". Inline a function containing eval can have
    //    large performance implications.

    final String fnRecursionName = fnNode.getFirstChild().getString();
    Preconditions.checkState(fnRecursionName != null);

    Predicate<Node> p =
        new Predicate<Node>() {
          public boolean apply(Node n) {
            if (n.getType() == Token.NAME) {
              return n.getString().equals("arguments")
                  || n.getString().equals("eval")
                  || n.getString().equals(fnName)
                  || (fnRecursionName.length() != 0 && n.getString().equals(fnRecursionName));
            }
            return false;
          }
        };

    return !NodeUtil.has(block, p, Predicates.<Node>alwaysTrue());
  }
 private static boolean isLhsOfEnhancedForExpression(Node n) {
   Node parent = n.getParent();
   if (NodeUtil.isNameDeclaration(parent)) {
     return isLhsOfEnhancedForExpression(parent);
   }
   return NodeUtil.isEnhancedFor(parent) && parent.getFirstChild() == n;
 }
  private void scanRoot(Node n) {
    if (n.isFunction()) {
      if (inputId == null) {
        inputId = NodeUtil.getInputId(n);
        // TODO(johnlenz): inputId maybe null if the FUNCTION node is detached
        // from the AST.
        // Is it meaningful to build a scope for detached FUNCTION node?
      }

      final Node fnNameNode = n.getFirstChild();
      final Node args = fnNameNode.getNext();
      final Node body = args.getNext();

      // Bleed the function name into the scope, if it hasn't
      // been declared in the outer scope.
      String fnName = fnNameNode.getString();
      if (!fnName.isEmpty() && NodeUtil.isFunctionExpression(n)) {
        declareVar(fnNameNode);
      }

      // Args: Declare function variables
      Preconditions.checkState(args.isParamList());
      for (Node a = args.getFirstChild(); a != null; a = a.getNext()) {
        Preconditions.checkState(a.isName());
        declareVar(a);
      }

      // Body
      scanVars(body);
    } else {
      // It's the global block
      Preconditions.checkState(scope.getParent() == null);
      scanVars(n);
    }
  }
  /**
   * If we haven't found a return value yet, try to look at the "return" statements in the function.
   */
  FunctionTypeBuilder inferReturnStatementsAsLastResort(@Nullable Node functionBlock) {
    if (functionBlock == null || compiler.getInput(sourceName).isExtern()) {
      return this;
    }
    Preconditions.checkArgument(functionBlock.getType() == Token.BLOCK);
    if (returnType == null) {
      boolean hasNonEmptyReturns = false;
      List<Node> worklist = Lists.newArrayList(functionBlock);
      while (!worklist.isEmpty()) {
        Node current = worklist.remove(worklist.size() - 1);
        int cType = current.getType();
        if (cType == Token.RETURN && current.getFirstChild() != null || cType == Token.THROW) {
          hasNonEmptyReturns = true;
          break;
        } else if (NodeUtil.isStatementBlock(current) || NodeUtil.isControlStructure(current)) {
          for (Node child = current.getFirstChild(); child != null; child = child.getNext()) {
            worklist.add(child);
          }
        }
      }

      if (!hasNonEmptyReturns) {
        returnType = typeRegistry.getNativeType(VOID_TYPE);
        returnTypeInferred = true;
      }
    }
    return this;
  }
    /** If this is an assign to a variable or its property, return it. Otherwise, return null. */
    static Assign maybeCreateAssign(Node assignNode) {
      Preconditions.checkState(NodeUtil.isAssignmentOp(assignNode));

      // Skip one level of GETPROPs or GETELEMs.
      //
      // Don't skip more than one level, because then we get into
      // situations where assigns to properties of properties will always
      // trigger side-effects, and the variable they're on cannot be removed.
      boolean isPropAssign = false;
      Node current = assignNode.getFirstChild();
      if (NodeUtil.isGet(current)) {
        current = current.getFirstChild();
        isPropAssign = true;

        if (current.getType() == Token.GETPROP
            && current.getLastChild().getString().equals("prototype")) {
          // Prototype properties sets should be considered like normal
          // property sets.
          current = current.getFirstChild();
        }
      }

      if (current.getType() == Token.NAME) {
        return new Assign(assignNode, current, isPropAssign);
      }
      return null;
    }
  private void handleReturn(Node node) {
    Node lastJump = null;
    for (Iterator<Node> iter = exceptionHandler.iterator(); iter.hasNext(); ) {
      Node curHandler = iter.next();
      if (NodeUtil.isFunction(curHandler)) {
        break;
      }
      if (NodeUtil.hasFinally(curHandler)) {
        if (lastJump == null) {
          createEdge(node, Branch.UNCOND, curHandler.getLastChild());
        } else {
          finallyMap.put(lastJump, computeFallThrough(curHandler.getLastChild()));
        }
        lastJump = curHandler;
      }
    }

    if (node.hasChildren()) {
      connectToPossibleExceptionHandler(node, node.getFirstChild());
    }

    if (lastJump == null) {
      createEdge(node, Branch.UNCOND, null);
    } else {
      finallyMap.put(lastJump, null);
    }
  }
  private void addExportMethod(
      Map<String, GenerateNodeContext> exports, String export, GenerateNodeContext context) {
    CodingConvention convention = compiler.getCodingConvention();

    // Emit the proper CALL expression.
    // This is an optimization to avoid exporting everything as a symbol
    // because exporting a property is significantly simpler/faster.
    // Only export the property if the parent is being exported or
    // if the parent is "prototype" and the grandparent is being exported.
    String parent = null;
    String grandparent = null;

    Node node = context.getNode().getFirstChild();
    if (node.isGetProp()) {
      Node parentNode = node.getFirstChild();
      parent = parentNode.getQualifiedName();
      if (parentNode.isGetProp()
          && parentNode.getLastChild().getString().equals(PROTOTYPE_PROPERTY)) {
        grandparent = parentNode.getFirstChild().getQualifiedName();
      }
    }

    boolean useExportSymbol = true;
    if (grandparent != null && exports.containsKey(grandparent)) {
      // grandparent is only set for properties exported off a prototype obj.
      useExportSymbol = false;
    } else if (parent != null && exports.containsKey(parent)) {
      useExportSymbol = false;
    }

    Node call;
    if (useExportSymbol) {
      // exportSymbol(publicPath, object);
      call =
          IR.call(
              NodeUtil.newQualifiedNameNode(
                  convention, exportSymbolFunction, context.getNode(), export),
              IR.string(export),
              NodeUtil.newQualifiedNameNode(convention, export, context.getNode(), export));
    } else {
      // exportProperty(object, publicName, symbol);
      String property = getPropertyName(node);
      call =
          IR.call(
              NodeUtil.newQualifiedNameNode(
                  convention, exportPropertyFunction, context.getNode(), exportPropertyFunction),
              NodeUtil.newQualifiedNameNode(
                  convention, parent, context.getNode(), exportPropertyFunction),
              IR.string(property),
              NodeUtil.newQualifiedNameNode(
                  convention, export, context.getNode(), exportPropertyFunction));
    }

    Node expression = IR.exprResult(call);
    annotate(expression);

    addStatement(context, expression);

    compiler.reportCodeChange();
  }
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      switch (n.getType()) {
          // Function calls
        case Token.CALL:
          Node child = n.getFirstChild();
          String name = null;
          // NOTE: The normalization pass insures that local names do not
          // collide with global names.
          if (child.isName()) {
            name = child.getString();
          } else if (child.isFunction()) {
            name = anonFunctionMap.get(child);
          } else if (NodeUtil.isFunctionObjectCall(n)) {
            Preconditions.checkState(NodeUtil.isGet(child));
            Node fnIdentifingNode = child.getFirstChild();
            if (fnIdentifingNode.isName()) {
              name = fnIdentifingNode.getString();
            } else if (fnIdentifingNode.isFunction()) {
              name = anonFunctionMap.get(fnIdentifingNode);
            }
          }

          if (name != null) {
            FunctionState fs = functionMap.get(name);

            // Only visit call-sites for functions that can be inlined.
            if (fs != null) {
              callback.visitCallSite(t, n, fs);
            }
          }
          break;
      }
    }
  /**
   * Connects cfgNode to the proper CATCH block if target subtree might throw an exception. If there
   * are FINALLY blocks reached before a CATCH, it will make the corresponding entry in finallyMap.
   */
  private void connectToPossibleExceptionHandler(Node cfgNode, Node target) {
    if (mayThrowException(target) && !exceptionHandler.isEmpty()) {
      Node lastJump = cfgNode;
      for (Node handler : exceptionHandler) {
        if (NodeUtil.isFunction(handler)) {
          return;
        }
        Preconditions.checkState(handler.getType() == Token.TRY);
        Node catchBlock = NodeUtil.getCatchBlock(handler);

        if (!NodeUtil.hasCatchHandler(catchBlock)) { // No catch but a FINALLY.
          if (lastJump == cfgNode) {
            createEdge(cfgNode, Branch.ON_EX, handler.getLastChild());
          } else {
            finallyMap.put(lastJump, handler.getLastChild());
          }
        } else { // Has a catch.
          if (lastJump == cfgNode) {
            createEdge(cfgNode, Branch.ON_EX, catchBlock);
            return;
          } else {
            finallyMap.put(lastJump, catchBlock);
          }
        }
        lastJump = handler;
      }
    }
  }
  /** Try to fold {@code left instanceof right} into {@code true} or {@code false}. */
  private Node tryFoldInstanceof(Node n, Node left, Node right) {
    Preconditions.checkArgument(n.isInstanceOf());

    // TODO(johnlenz) Use type information if available to fold
    // instanceof.
    if (NodeUtil.isLiteralValue(left, true) && !mayHaveSideEffects(right)) {

      Node replacementNode = null;

      if (NodeUtil.isImmutableValue(left)) {
        // Non-object types are never instances.
        replacementNode = IR.falseNode();
      } else if (right.isName() && "Object".equals(right.getString())) {
        replacementNode = IR.trueNode();
      }

      if (replacementNode != null) {
        n.getParent().replaceChild(n, replacementNode);
        reportCodeChange();
        return replacementNode;
      }
    }

    return n;
  }
    public void findNamedFunctions(NodeTraversal t, Node n, Node parent) {
      if (!NodeUtil.isStatement(n)) {
        // There aren't any interesting functions here.
        return;
      }

      switch (n.getType()) {
          // Functions expressions in the form of:
          //   var fooFn = function(x) { return ... }
        case Token.VAR:
          Preconditions.checkState(n.hasOneChild());
          Node nameNode = n.getFirstChild();
          if (nameNode.isName()
              && nameNode.hasChildren()
              && nameNode.getFirstChild().isFunction()) {
            maybeAddFunction(new FunctionVar(n), t.getModule());
          }
          break;

          // Named functions
          // function Foo(x) { return ... }
        case Token.FUNCTION:
          Preconditions.checkState(NodeUtil.isStatementBlock(parent) || parent.isLabel());
          if (!NodeUtil.isFunctionExpression(n)) {
            Function fn = new NamedFunction(n);
            maybeAddFunction(fn, t.getModule());
          }
          break;
      }
    }
  static TernaryValue evaluateComparison(Token op, Node left, Node right, boolean useTypes) {
    // Don't try to minimize side-effects here.
    if (NodeUtil.mayHaveSideEffects(left) || NodeUtil.mayHaveSideEffects(right)) {
      return TernaryValue.UNKNOWN;
    }

    switch (op) {
      case EQ:
        return tryAbstractEqualityComparison(left, right, useTypes);
      case NE:
        return tryAbstractEqualityComparison(left, right, useTypes).not();
      case SHEQ:
        return tryStrictEqualityComparison(left, right, useTypes);
      case SHNE:
        return tryStrictEqualityComparison(left, right, useTypes).not();
      case LT:
        return tryAbstractRelationalComparison(left, right, useTypes, false);
      case GT:
        return tryAbstractRelationalComparison(right, left, useTypes, false);
      case LE:
        return tryAbstractRelationalComparison(right, left, useTypes, true).not();
      case GE:
        return tryAbstractRelationalComparison(left, right, useTypes, true).not();
    }
    throw new IllegalStateException("Unexpected operator for comparison");
  }
  /**
   * Replaces a GETPROP a.b.c with a NAME a$b$c.
   *
   * @param alias A flattened prefix name (e.g. "a$b")
   * @param n The GETPROP node corresponding to the original name (e.g. "a.b")
   * @param parent {@code n}'s parent
   * @param originalName String version of the property name.
   */
  private void flattenNameRef(String alias, Node n, Node parent, String originalName) {
    Preconditions.checkArgument(
        n.isGetProp(), "Expected GETPROP, found %s. Node: %s", Token.name(n.getType()), n);

    // BEFORE:
    //   getprop
    //     getprop
    //       name a
    //       string b
    //     string c
    // AFTER:
    //   name a$b$c
    Node ref = NodeUtil.newName(compiler, alias, n, originalName);
    NodeUtil.copyNameAnnotations(n.getLastChild(), ref);
    if (parent.isCall() && n == parent.getFirstChild()) {
      // The node was a call target, we are deliberately flatten these as
      // we node the "this" isn't provided by the namespace. Mark it as such:
      parent.putBooleanProp(Node.FREE_CALL, true);
    }

    TypeI type = n.getTypeI();
    if (type != null) {
      ref.setTypeI(type);
    }

    parent.replaceChild(n, ref);
    compiler.reportCodeChange();
  }
  /**
   * Adds an interface for the given ClassDefinition to externs. This allows generated setter
   * functions for read-only properties to avoid renaming altogether.
   *
   * @see https://www.polymer-project.org/0.8/docs/devguide/properties.html#read-only
   */
  private void addInterfaceExterns(
      final ClassDefinition cls, List<MemberDefinition> readOnlyProps) {
    Node block = IR.block();

    String interfaceName = getInterfaceName(cls);
    Node fnNode = IR.function(IR.name(""), IR.paramList(), IR.block());
    Node varNode = IR.var(NodeUtil.newQName(compiler, interfaceName), fnNode);

    JSDocInfoBuilder info = new JSDocInfoBuilder(true);
    info.recordInterface();
    varNode.setJSDocInfo(info.build());
    block.addChildToBack(varNode);

    appendPropertiesToBlock(cls, block, interfaceName + ".prototype.");
    for (MemberDefinition prop : readOnlyProps) {
      // Add all _set* functions to avoid renaming.
      String propName = prop.name.getString();
      String setterName = "_set" + propName.substring(0, 1).toUpperCase() + propName.substring(1);
      Node setterExprNode =
          IR.exprResult(NodeUtil.newQName(compiler, interfaceName + ".prototype." + setterName));

      JSDocInfoBuilder setterInfo = new JSDocInfoBuilder(true);
      JSTypeExpression propType = getTypeFromProperty(prop);
      setterInfo.recordParameter(propName, propType);
      setterExprNode.getFirstChild().setJSDocInfo(setterInfo.build());

      block.addChildToBack(setterExprNode);
    }

    Node parent = polymerElementExterns.getParent();
    Node stmts = block.removeChildren();
    parent.addChildrenToBack(stmts);

    compiler.reportCodeChange();
  }
 /**
  * @param name The Name whose properties references should be updated.
  * @param value The value to use when rewriting.
  * @param depth The chain depth.
  * @param newNodes Expression nodes that have been updated.
  */
 private static void rewriteAliasProps(Name name, Node value, int depth, Set<AstChange> newNodes) {
   if (name.props == null) {
     return;
   }
   Preconditions.checkState(!value.matchesQualifiedName(name.getFullName()));
   for (Name prop : name.props) {
     rewriteAliasProps(prop, value, depth + 1, newNodes);
     List<Ref> refs = new ArrayList<>(prop.getRefs());
     for (Ref ref : refs) {
       Node target = ref.node;
       for (int i = 0; i <= depth; i++) {
         if (target.isGetProp()) {
           target = target.getFirstChild();
         } else if (NodeUtil.isObjectLitKey(target)) {
           // Object literal key definitions are a little trickier, as we
           // need to find the assignment target
           Node gparent = target.getParent().getParent();
           if (gparent.isAssign()) {
             target = gparent.getFirstChild();
           } else {
             Preconditions.checkState(NodeUtil.isObjectLitKey(gparent));
             target = gparent;
           }
         } else {
           throw new IllegalStateException("unexpected: " + target);
         }
       }
       Preconditions.checkState(target.isGetProp() || target.isName());
       target.getParent().replaceChild(target, value.cloneTree());
       prop.removeRef(ref);
       // Rescan the expression root.
       newNodes.add(new AstChange(ref.module, ref.scope, ref.node));
     }
   }
 }
  private void addStatement(GenerateNodeContext context, Node stmt) {
    CodingConvention convention = compiler.getCodingConvention();

    Node n = context.getNode();
    Node exprRoot = n;
    while (!NodeUtil.isStatementBlock(exprRoot.getParent())) {
      exprRoot = exprRoot.getParent();
    }

    // It's important that any class-building calls (goog.inherits)
    // come right after the class definition, so move the export after that.
    while (true) {
      Node next = exprRoot.getNext();
      if (next != null
          && NodeUtil.isExprCall(next)
          && convention.getClassesDefinedByCall(next.getFirstChild()) != null) {
        exprRoot = next;
      } else {
        break;
      }
    }

    Node block = exprRoot.getParent();
    block.addChildAfter(stmt, exprRoot);
  }
  private void addToDefinePropertiesObject(ClassDeclarationMetadata metadata, Node member) {
    Node obj =
        member.isStaticMember()
            ? metadata.definePropertiesObjForClass
            : metadata.definePropertiesObjForPrototype;
    Node prop = NodeUtil.getFirstPropMatchingKey(obj, member.getString());
    if (prop == null) {
      prop =
          IR.objectlit(
              IR.stringKey("configurable", IR.trueNode()),
              IR.stringKey("enumerable", IR.trueNode()));
      obj.addChildToBack(IR.stringKey(member.getString(), prop));
    }

    Node function = member.getLastChild();
    JSDocInfoBuilder info = JSDocInfoBuilder.maybeCopyFrom(NodeUtil.getBestJSDocInfo(function));

    info.recordThisType(
        new JSTypeExpression(
            new Node(Token.BANG, IR.string(metadata.fullClassName)), member.getSourceFileName()));
    Node stringKey =
        IR.stringKey(member.isGetterDef() ? "get" : "set", function.detachFromParent());
    stringKey.setJSDocInfo(info.build());
    prop.addChildToBack(stringKey);
    prop.useSourceInfoIfMissingFromForTree(member);
  }
 /**
  * Returns the nth argument node given a usage site for a direct function call or for a
  * func.call() node.
  */
 private static Node getArgumentForCallOrNewOrDotCall(UseSite site, final int argIndex) {
   int adjustedArgIndex = argIndex;
   Node parent = site.node.getParent();
   if (NodeUtil.isFunctionObjectCall(parent)) {
     adjustedArgIndex++;
   }
   return NodeUtil.getArgumentForCallOrNew(parent, adjustedArgIndex);
 }
Example #20
0
 /**
  * Processes array literals or calls containing spreads. Eg.: [1, 2, ...x, 4, 5] => [1,
  * 2].concat(x, [4, 5]); Eg.: f(...arr) => f.apply(null, arr) Eg.: new F(...args) => new
  * Function.prototype.bind.apply(F, [].concat(args))
  */
 private void visitArrayLitOrCallWithSpread(Node node, Node parent) {
   Preconditions.checkArgument(node.isCall() || node.isArrayLit() || node.isNew());
   List<Node> groups = new ArrayList<>();
   Node currGroup = null;
   Node callee = node.isArrayLit() ? null : node.removeFirstChild();
   Node currElement = node.removeFirstChild();
   while (currElement != null) {
     if (currElement.isSpread()) {
       if (currGroup != null) {
         groups.add(currGroup);
         currGroup = null;
       }
       groups.add(currElement.removeFirstChild());
     } else {
       if (currGroup == null) {
         currGroup = IR.arraylit();
       }
       currGroup.addChildToBack(currElement);
     }
     currElement = node.removeFirstChild();
   }
   if (currGroup != null) {
     groups.add(currGroup);
   }
   Node result = null;
   Node joinedGroups =
       IR.call(
           IR.getprop(IR.arraylit(), IR.string("concat")),
           groups.toArray(new Node[groups.size()]));
   if (node.isArrayLit()) {
     result = joinedGroups;
   } else if (node.isCall()) {
     if (NodeUtil.mayHaveSideEffects(callee) && callee.isGetProp()) {
       Node statement = node;
       while (!NodeUtil.isStatement(statement)) {
         statement = statement.getParent();
       }
       Node freshVar = IR.name(FRESH_SPREAD_VAR + freshSpreadVarCounter++);
       Node n = IR.var(freshVar.cloneTree());
       n.useSourceInfoIfMissingFromForTree(statement);
       statement.getParent().addChildBefore(n, statement);
       callee.addChildToFront(IR.assign(freshVar.cloneTree(), callee.removeFirstChild()));
       result = IR.call(IR.getprop(callee, IR.string("apply")), freshVar, joinedGroups);
     } else {
       Node context = callee.isGetProp() ? callee.getFirstChild().cloneTree() : IR.nullNode();
       result = IR.call(IR.getprop(callee, IR.string("apply")), context, joinedGroups);
     }
   } else {
     Node bindApply =
         NodeUtil.newQualifiedNameNode(
             compiler.getCodingConvention(), "Function.prototype.bind.apply");
     result = IR.newNode(bindApply, callee, joinedGroups);
   }
   result.useSourceInfoIfMissingFromForTree(node);
   parent.replaceChild(node, result);
   compiler.reportCodeChange();
 }
 private void checkClassReassignment(Node clazz) {
   Node name = NodeUtil.getClassNameNode(clazz);
   Node enclosingFunction = NodeUtil.getEnclosingFunction(clazz);
   if (enclosingFunction == null) {
     return;
   }
   CheckClassAssignments checkAssigns = new CheckClassAssignments(name);
   NodeTraversal.traverseEs6(compiler, enclosingFunction, checkAssigns);
 }
  private Node tryFoldArrayAccess(Node n, Node left, Node right) {
    // If GETPROP/GETELEM is used as assignment target the array literal is
    // acting as a temporary we can't fold it here:
    //    "[][0] += 1"
    if (NodeUtil.isAssignmentTarget(n)) {
      return n;
    }

    if (!right.isNumber()) {
      // Sometimes people like to use complex expressions to index into
      // arrays, or strings to index into array methods.
      return n;
    }

    double index = right.getDouble();
    int intIndex = (int) index;
    if (intIndex != index) {
      report(INVALID_GETELEM_INDEX_ERROR, right);
      return n;
    }

    if (intIndex < 0) {
      report(INDEX_OUT_OF_BOUNDS_ERROR, right);
      return n;
    }

    Node current = left.getFirstChild();
    Node elem = null;
    for (int i = 0; current != null; i++) {
      if (i != intIndex) {
        if (mayHaveSideEffects(current)) {
          return n;
        }
      } else {
        elem = current;
      }

      current = current.getNext();
    }

    if (elem == null) {
      report(INDEX_OUT_OF_BOUNDS_ERROR, right);
      return n;
    }

    if (elem.isEmpty()) {
      elem = NodeUtil.newUndefinedNode(elem);
    } else {
      left.removeChild(elem);
    }

    // Replace the entire GETELEM with the value
    n.getParent().replaceChild(n, elem);
    reportCodeChange();
    return elem;
  }
    @Override
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (!n.isFunction()) {
        return;
      }

      int id = functionNames.getFunctionId(n);
      if (id < 0) {
        // Function node was added during compilation; don't instrument.
        return;
      }

      String name = functionNames.getFunctionName(n);

      if (!reportFunctionName.isEmpty()) {
        Node body = n.getLastChild();
        Node call =
            IR.call(
                IR.name(reportFunctionName), IR.number(id), IR.string(name), IR.name("arguments"));
        call.putBooleanProp(Node.FREE_CALL, true);
        Node expr = IR.exprResult(call);
        expr.useSourceInfoFromForTree(n);
        body.addChildToFront(expr);
        compiler.reportCodeChange();
      }

      if (!reportFunctionExitName.isEmpty()) {
        (new InstrumentReturns(id, name)).process(n);
      }

      if (!definedFunctionName.isEmpty()) {
        Node call = IR.call(IR.name(definedFunctionName), IR.number(id), IR.string(name));
        call.putBooleanProp(Node.FREE_CALL, true);
        call.useSourceInfoFromForTree(n);
        Node expr = NodeUtil.newExpr(call);

        Node addingRoot = null;
        if (NodeUtil.isFunctionDeclaration(n)) {
          JSModule module = t.getModule();
          addingRoot = compiler.getNodeForCodeInsertion(module);
          addingRoot.addChildToFront(expr);
        } else {
          Node beforeChild = n;
          for (Node ancestor : n.getAncestors()) {
            Token type = ancestor.getType();
            if (type == Token.BLOCK || type == Token.SCRIPT) {
              addingRoot = ancestor;
              break;
            }
            beforeChild = ancestor;
          }
          addingRoot.addChildBefore(expr, beforeChild);
        }
        compiler.reportCodeChange();
      }
    }
  /** Appends all required behavior functions and non-property members to the given block. */
  private void appendBehaviorMembersToBlock(final ClassDefinition cls, Node block) {
    String qualifiedPath = cls.target.getQualifiedName() + ".prototype.";
    Map<String, Node> nameToExprResult = new HashMap<>();
    for (BehaviorDefinition behavior : cls.behaviors) {
      for (MemberDefinition behaviorFunction : behavior.functionsToCopy) {
        String fnName = behaviorFunction.name.getString();
        // Don't copy functions already defined by the element itself.
        if (NodeUtil.getFirstPropMatchingKey(cls.descriptor, fnName) != null) {
          continue;
        }

        // Avoid copying over the same function twice. The last definition always wins.
        if (nameToExprResult.containsKey(fnName)) {
          block.removeChild(nameToExprResult.get(fnName));
        }

        Node fnValue = behaviorFunction.value.cloneTree();
        Node exprResult =
            IR.exprResult(IR.assign(NodeUtil.newQName(compiler, qualifiedPath + fnName), fnValue));
        JSDocInfoBuilder info = JSDocInfoBuilder.maybeCopyFrom(behaviorFunction.info);

        // Behaviors whose declarations are not in the global scope may contain references to
        // symbols which do not exist in the element's scope. Only copy a function stub. See
        if (!behavior.isGlobalDeclaration) {
          NodeUtil.getFunctionBody(fnValue).removeChildren();
        }

        exprResult.getFirstChild().setJSDocInfo(info.build());
        block.addChildToBack(exprResult);
        nameToExprResult.put(fnName, exprResult);
      }

      // Copy other members.
      for (MemberDefinition behaviorProp : behavior.nonPropertyMembersToCopy) {
        String propName = behaviorProp.name.getString();
        if (nameToExprResult.containsKey(propName)) {
          block.removeChild(nameToExprResult.get(propName));
        }

        Node exprResult = IR.exprResult(NodeUtil.newQName(compiler, qualifiedPath + propName));
        JSDocInfoBuilder info = JSDocInfoBuilder.maybeCopyFrom(behaviorProp.info);

        if (behaviorProp.name.isGetterDef()) {
          info = new JSDocInfoBuilder(true);
          if (behaviorProp.info != null && behaviorProp.info.getReturnType() != null) {
            info.recordType(behaviorProp.info.getReturnType());
          }
        }

        exprResult.getFirstChild().setJSDocInfo(info.build());
        block.addChildToBack(exprResult);
        nameToExprResult.put(propName, exprResult);
      }
    }
  }
  /** Scans and gather variables declarations under a Node */
  private void scanVars(Node n, Node parent) {
    switch (n.getType()) {
      case Token.VAR:
        // Declare all variables. e.g. var x = 1, y, z;
        for (Node child = n.getFirstChild(); child != null; ) {
          Node next = child.getNext();
          Preconditions.checkState(child.getType() == Token.NAME);

          String name = child.getString();
          declareVar(name, child, n, parent, null, n);
          child = next;
        }
        return;

      case Token.FUNCTION:
        if (NodeUtil.isFunctionExpression(n)) {
          return;
        }

        String fnName = n.getFirstChild().getString();
        if (fnName.isEmpty()) {
          // This is invalid, but allow it so the checks can catch it.
          return;
        }
        declareVar(fnName, n.getFirstChild(), n, parent, null, n);
        return; // should not examine function's children

      case Token.CATCH:
        Preconditions.checkState(n.getChildCount() == 2);
        Preconditions.checkState(n.getFirstChild().getType() == Token.NAME);
        // the first child is the catch var and the third child
        // is the code block

        final Node var = n.getFirstChild();
        final Node block = var.getNext();

        declareVar(var.getString(), var, n, parent, null, n);
        scanVars(block, n);
        return; // only one child to scan

      case Token.SCRIPT:
        sourceName = (String) n.getProp(Node.SOURCENAME_PROP);
        break;
    }

    // Variables can only occur in statement-level nodes, so
    // we only need to traverse children in a couple special cases.
    if (NodeUtil.isControlStructure(n) || NodeUtil.isStatementBlock(n)) {
      for (Node child = n.getFirstChild(); child != null; ) {
        Node next = child.getNext();
        scanVars(child, n);
        child = next;
      }
    }
  }
    Assign(Node assignNode, Node nameNode, boolean isPropertyAssign) {
      Preconditions.checkState(NodeUtil.isAssignmentOp(assignNode));
      this.assignNode = assignNode;
      this.nameNode = nameNode;
      this.isPropertyAssign = isPropertyAssign;

      this.mayHaveSecondarySideEffects =
          assignNode.getParent().getType() != Token.EXPR_RESULT
              || NodeUtil.mayHaveSideEffects(assignNode.getFirstChild())
              || NodeUtil.mayHaveSideEffects(assignNode.getLastChild());
    }
  /** @return The difference between the function definition cost and inline cost. */
  private static int inlineCostDelta(Node fnNode, Set<String> namesToAlias, InliningMode mode) {
    // The part of the function that is never inlined:
    //    "function xx(xx,xx){}" (15 + (param count * 3) -1;
    int paramCount = NodeUtil.getFnParameters(fnNode).getChildCount();
    int commaCount = (paramCount > 1) ? paramCount - 1 : 0;
    int costDeltaFunctionOverhead =
        15 + commaCount + (paramCount * InlineCostEstimator.ESTIMATED_IDENTIFIER_COST);

    Node block = fnNode.getLastChild();
    if (!block.hasChildren()) {
      // Assume the inline cost is zero for empty functions.
      return -costDeltaFunctionOverhead;
    }

    if (mode == InliningMode.DIRECT) {
      // The part of the function that is inlined using direct inlining:
      //    "return " (7)
      return -(costDeltaFunctionOverhead + 7);
    } else {
      int aliasCount = namesToAlias.size();

      // Originally, we estimated purely base on the function code size, relying
      // on later optimizations. But that did not produce good results, so here
      // we try to estimate the something closer to the actual inlined coded.

      // NOTE 1: Result overhead is only if there is an assignment, but
      // getting that information would require some refactoring.
      // NOTE 2: The aliasing overhead is currently an under-estimate,
      // as some parameters are aliased because of the parameters used.
      // Perhaps we should just assume all parameters will be aliased?
      final int INLINE_BLOCK_OVERHEAD = 4; // "X:{}"
      final int PER_RETURN_OVERHEAD = 2; // "return" --> "break X"
      final int PER_RETURN_RESULT_OVERHEAD = 3; // "XX="
      final int PER_ALIAS_OVERHEAD = 3; // "XX="

      // TODO(johnlenz): Counting the number of returns is relatively expensive
      //   this information should be determined during the traversal and
      //   cached.
      int returnCount =
          NodeUtil.getNodeTypeReferenceCount(
              block, Token.RETURN, new NodeUtil.MatchShallowStatement());
      int resultCount = (returnCount > 0) ? returnCount - 1 : 0;
      int baseOverhead = (returnCount > 0) ? INLINE_BLOCK_OVERHEAD : 0;

      int overhead =
          baseOverhead
              + returnCount * PER_RETURN_OVERHEAD
              + resultCount * PER_RETURN_RESULT_OVERHEAD
              + aliasCount * PER_ALIAS_OVERHEAD;

      return (overhead - costDeltaFunctionOverhead);
    }
  }
    public void visit(NodeTraversal t, Node n, Node parent) {
      if (n.getType() != Token.FUNCTION) {
        return;
      }

      int id = functionNames.getFunctionId(n);
      if (id < 0) {
        // Function node was added during compilation; don't instrument.
        return;
      }

      if (reportFunctionName.length() != 0) {
        Node body = n.getFirstChild().getNext().getNext();
        Node call =
            new Node(
                Token.CALL, Node.newString(Token.NAME, reportFunctionName), Node.newNumber(id));
        Node expr = new Node(Token.EXPR_RESULT, call);
        body.addChildToFront(expr);
        compiler.reportCodeChange();
      }

      if (reportFunctionExitName.length() != 0) {
        Node body = n.getFirstChild().getNext().getNext();
        (new InstrumentReturns(id)).process(body);
      }

      if (definedFunctionName.length() != 0) {
        Node call =
            new Node(
                Token.CALL, Node.newString(Token.NAME, definedFunctionName), Node.newNumber(id));
        Node expr = NodeUtil.newExpr(call);

        Node addingRoot = null;
        if (NodeUtil.isFunctionDeclaration(n)) {
          JSModule module = t.getModule();
          addingRoot = compiler.getNodeForCodeInsertion(module);
          addingRoot.addChildToFront(expr);
        } else {
          Node beforeChild = n;
          for (Node ancestor : n.getAncestors()) {
            int type = ancestor.getType();
            if (type == Token.BLOCK || type == Token.SCRIPT) {
              addingRoot = ancestor;
              break;
            }
            beforeChild = ancestor;
          }
          addingRoot.addChildBefore(expr, beforeChild);
        }
        compiler.reportCodeChange();
      }
    }
 private Node baseCall(Node clazz, String methodName, Node arguments) {
   boolean useUnique = NodeUtil.isStatement(clazz) && !isInFunction(clazz);
   String uniqueClassString =
       useUnique ? getUniqueClassName(NodeUtil.getClassName(clazz)) : NodeUtil.getClassName(clazz);
   Node uniqueClassName =
       NodeUtil.newQualifiedNameNode(compiler.getCodingConvention(), uniqueClassString);
   Node base = IR.getprop(uniqueClassName, IR.string("base"));
   Node call = IR.call(base, IR.thisNode(), IR.string(methodName));
   if (arguments != null) {
     call.addChildrenToBack(arguments);
   }
   return call;
 }
 boolean isLvalue() {
   Node parent = getParent();
   int parentType = parent.getType();
   return (parentType == Token.VAR && nameNode.getFirstChild() != null)
       || (parentType == Token.LET && nameNode.getFirstChild() != null)
       || (parentType == Token.CONST && nameNode.getFirstChild() != null)
       || (parentType == Token.DEFAULT_VALUE && parent.getFirstChild() == nameNode)
       || parentType == Token.INC
       || parentType == Token.DEC
       || parentType == Token.CATCH
       || (NodeUtil.isAssignmentOp(parent) && parent.getFirstChild() == nameNode)
       || isLhsOfEnhancedForExpression(nameNode)
       || NodeUtil.isLhsByDestructuring(nameNode);
 }