import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
public void enterScope(NodeTraversal t) {
  ControlFlowGraph<Node> cfg = t.getControlFlowGraph();

  for (DiGraphEdge<Node, Branch> s : cfg.getImplicitReturn().getInEdges()) {
    Node exitNode = s.getSource().getValue();
    if (exitNode.getType() != Token.RETURN ||
        exitNode.getFirstChild() == null ||
        exitNode.getFirstChild().getType() != Token.THIS) {
      badFunctionNodes.add(t.getScopeRoot());
      return;
    }
  }

  goodFunctionNodes.add(t.getScopeRoot());
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
protected void initialize() {
  orderedWorkSet.clear();
  for (DiGraphNode<N, Branch> node : getCfg().getDirectedGraphNodes()) {
    List<DiGraphEdge<N, Branch>> edgeList =
      getCfg().getOutEdges(node.getValue());
    int outEdgeCount = edgeList.size();
    List<L> outLattices = Lists.newArrayList();
    for (int i = 0; i < outEdgeCount; i++) {
      outLattices.add(createInitialEstimateLattice());
    }
    node.setAnnotation(new BranchedFlowState<L>(
        createInitialEstimateLattice(), outLattices));
    if (node != getCfg().getImplicitReturn()) {
      orderedWorkSet.add(node);
    }
  }
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Given a graph G with nodes A and B, this algorithm determines if all paths
 * from A to B contain at least one node satisfying a given predicate.
 *
 * Note that nodePredicate is not necessarily called for all nodes in G nor is
 * edgePredicate called for all edges in G.
 *
 * @param graph Graph G to analyze.
 * @param a The node A.
 * @param b The node B.
 * @param nodePredicate Predicate which at least one node on each path from an
 *     A node to B (inclusive) must match.
 * @param edgePredicate Edges to consider as part of the graph. Edges in
 *     graph that don't match edgePredicate will be ignored.
 */
CheckPathsBetweenNodes(DiGraph<N, E> graph, DiGraphNode<N, E> a,
    DiGraphNode<N, E> b, Predicate<N> nodePredicate,
    Predicate<DiGraphEdge<N, E>> edgePredicate) {
  this.nodePredicate = nodePredicate;
  this.edgePredicate = edgePredicate;

  graph.pushNodeAnnotations();
  graph.pushEdgeAnnotations();

  discoverBackEdges(a);
  result = checkAllPathsWithoutBackEdges(a, b);

  graph.popNodeAnnotations();
  graph.popEdgeAnnotations();
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Verify that all non-looping paths from {@code a} to {@code b} pass
 * through at least one node where {@code nodePredicate} is true.
 */
private boolean checkAllPathsWithoutBackEdges(DiGraphNode<N, E> a,
    DiGraphNode<N, E> b) {
  if (nodePredicate.apply(a.getValue())) {
    return true;
  }
  if (a == b) {
    return false;
  }
  for (DiGraphEdge<N, E> e : a.getOutEdges()) {
    if (ignoreEdge(e)) {
      continue;
    }
    if (e.getAnnotation() == BACK_EDGE) {
      continue;
    }
    DiGraphNode<N, E> next = e.getDestination();
    if (!checkAllPathsWithoutBackEdges(next, b)) {
      return false;
    }
  }
  return true;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
public boolean apply(DiGraphEdge<Node, ControlFlowGraph.Branch> input) {
  // First skill all exceptions.
  Branch branch = input.getValue();
  if (branch == Branch.ON_EX) {
    return false;
  } else if (branch.isConditional()) {
    Node condition = NodeUtil.getConditionExpression(
        input.getSource().getValue());
    // TODO(user): We CAN make this bit smarter just looking at
    // constants. We DO have a full blown ReverseAbstractInterupter and
    // type system that can evaluate some impressions' boolean value but
    // for now we will keep this pass lightweight.
    if (condition != null && NodeUtil.isLiteralValue(condition) ) {
      return NodeUtil.getBooleanValue(condition) ==
        (Branch.ON_TRUE == branch);
    }
  }
  return true;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
public void process(Node externs, Node root) {
  if (nameGraph == null) {
    NameReferenceGraphConstruction c =
        new NameReferenceGraphConstruction(compiler);
    c.process(externs, root);
    nameGraph = c.getNameReferenceGraph();
  }
  
  for (DiGraphNode<Name, Reference> node : 
      nameGraph.getDirectedGraphNodes()) {
    Name name = node.getValue();
    if (name.canChangeSignature()) {
      List<DiGraphEdge<Name, Reference>> edges = node.getInEdges();        
      tryEliminateConstantArgs(name, edges);
      tryEliminateOptionalArgs(name, edges);
    }
  }
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Removes any optional parameters if no callers specifies it as an argument.
 * @param name The name of the function to optimize. 
 * @param edges All the references to this name.
 */
private void tryEliminateOptionalArgs(Name name,
    List<DiGraphEdge<Name, Reference>> edges) {
  
  // Count the maximum number of arguments passed into this function all
  // all points of the program.
  int maxArgs = -1;

  for (DiGraphEdge<Name, Reference> refEdge : edges) {
    Reference ref = refEdge.getValue();
    Node call = ref.parent;

    if (isCallSite(ref)) {
      int numArgs = call.getChildCount() - 1;
      if (numArgs > maxArgs) {
        maxArgs = numArgs;
      }
    } // else this is a definition or a dereference, ignore it.
  }

  for (Definition definition : name.getDeclarations()) {
    eliminateParamsAfter(definition.getRValue(), maxArgs);
  }
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
LiveVariableLattice flowThrough(Node node, LiveVariableLattice input) {
  final BitSet gen = new BitSet(input.liveSet.size());
  final BitSet kill = new BitSet(input.liveSet.size());

  // Make kills conditional if the node can end abruptly by an exception.
  boolean conditional = false;
  List<DiGraphEdge<Node, Branch>> edgeList = getCfg().getOutEdges(node);
  for (DiGraphEdge<Node, Branch> edge : edgeList) {
    if (Branch.ON_EX.equals(edge.getValue())) {
      conditional = true;
    }
  }
  computeGenKill(node, gen, kill, conditional);
  LiveVariableLattice result = new LiveVariableLattice(input);
  // L_in = L_out - Kill + Gen
  result.liveSet.andNot(kill);
  result.liveSet.or(gen);
  return result;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Gets all the control flow edges from some node with the first token to
 * some node with the second token.
 */
private static List<DiGraphEdge<Node, Branch>> getAllEdges(
    ControlFlowGraph<Node> cfg, int startToken, int endToken) {
  List<DiGraphEdge<Node, Branch>> edges = getAllEdges(cfg);
  Iterator<DiGraphEdge<Node, Branch>> it = edges.iterator();
  while (it.hasNext()) {
    DiGraphEdge<Node, Branch> edge = it.next();
    Node startNode = edge.getSource().getValue();
    Node endNode = edge.getDestination().getValue();
    if (startNode == null || endNode == null ||
        startNode.getType() != startToken || endNode.getType() != endToken) {
      it.remove();
    }
  }
  return edges;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Gets all the control flow edges of the given type from some node with
 * the first token to some node with the second token.
 * This edge must flow from a parent to one of its descendants.
 */
private static List<DiGraphEdge<Node, Branch>> getAllDownEdges(
    ControlFlowGraph<Node> cfg, int startToken, int endToken, Branch type) {
  List<DiGraphEdge<Node, Branch>> edges =
      getAllEdges(cfg, startToken, endToken, type);
  Iterator<DiGraphEdge<Node, Branch>> it = edges.iterator();
  while (it.hasNext()) {
    DiGraphEdge<Node, Branch> edge = it.next();
    Node source = edge.getSource().getValue();
    Node dest = edge.getDestination().getValue();
    if (!isAncestor(source, dest)) {
      it.remove();
    }
  }

  return edges;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Generate a description of a specific edge between two nodes.
 * For each edge, name the element being linked, the location of the
 * reference in the source file, and the type of the reference.
 *
 * @param builder contents of the report to be generated
 * @param referencedDecl name of the declaration being referenced
 * @param edge the graph edge being described
 */
private void generateEdgeReport(StringBuilder builder,
    Name referencedDecl, DiGraphEdge<Name, Reference> edge) {
  String srcDeclName = referencedDecl.getQualifiedName();
  builder.append("<li><A HREF=\"#" + srcDeclName + "\">");
  builder.append(srcDeclName);
  builder.append("</a> ");

  Node def = edge.getValue().getSite();
  int lineNumber = def.getLineno();
  int columnNumber = def.getCharno();
  String sourceFile = getSourceFile(def);

  generateSourceReferenceLink(builder, sourceFile, lineNumber, columnNumber);

  JSType defType = edge.getValue().getSite().getJSType();
  generateType(builder, defType);
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Verify that all non-looping paths from {@code a} to {@code b} pass
 * through at least one node where {@code nodePredicate} is true.
 */
private boolean checkAllPathsWithoutBackEdges(DiGraphNode<N, E> a,
    DiGraphNode<N, E> b) {
  if (nodePredicate.apply(a.getValue()) &&
      (inclusive || (a != start && a != end))) {
    return true;
  }
  if (a == b) {
    return false;
  }
  for (DiGraphEdge<N, E> e : a.getOutEdges()) {
    if (ignoreEdge(e)) {
      continue;
    }
    if (e.getAnnotation() == BACK_EDGE) {
      continue;
    }
    DiGraphNode<N, E> next = e.getDestination();
    if (!checkAllPathsWithoutBackEdges(next, b)) {
      return false;
    }
  }
  return true;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Verify that some non-looping paths from {@code a} to {@code b} pass
 * through at least one node where {@code nodePredicate} is true.
 */
private boolean checkSomePathsWithoutBackEdges(DiGraphNode<N, E> a,
    DiGraphNode<N, E> b) {
  if (nodePredicate.apply(a.getValue()) &&
      (inclusive || (a != start && a != end))) {
    return true;
  }
  if (a == b) {
    return false;
  }
  for (DiGraphEdge<N, E> e : a.getOutEdges()) {
    if (ignoreEdge(e)) {
      continue;
    }
    if (e.getAnnotation() == BACK_EDGE) {
      continue;
    }
    DiGraphNode<N, E> next = e.getDestination();
    if (checkSomePathsWithoutBackEdges(next, b)) {
      return true;
    }
  }
  return false;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
public boolean apply(DiGraphEdge<Node, ControlFlowGraph.Branch> input) {
  // First skill all exceptions.
  Branch branch = input.getValue();
  if (branch == Branch.ON_EX) {
    return false;
  } else if (branch.isConditional()) {
    Node condition = NodeUtil.getConditionExpression(
        input.getSource().getValue());
    // TODO(user): We CAN make this bit smarter just looking at
    // constants. We DO have a full blown ReverseAbstractInterupter and
    // type system that can evaluate some impressions' boolean value but
    // for now we will keep this pass lightweight.
    if (condition != null) {
      TernaryValue val = NodeUtil.getBooleanValue(condition);
      if (val != TernaryValue.UNKNOWN) {
        return val.toBoolean(true) == (Branch.ON_TRUE == branch);
      }
    }
  }
  return true;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
public void process(Node externs, Node root) {
  if (nameGraph == null) {
    NameReferenceGraphConstruction c =
        new NameReferenceGraphConstruction(compiler);
    c.process(externs, root);
    nameGraph = c.getNameReferenceGraph();
  }

  for (DiGraphNode<Name, Reference> node :
      nameGraph.getDirectedGraphNodes()) {
    Name name = node.getValue();
    if (name.canChangeSignature()) {
      List<DiGraphEdge<Name, Reference>> edges = node.getInEdges();
      tryEliminateConstantArgs(name, edges);
      tryEliminateOptionalArgs(name, edges);
    }
  }
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
/**
 * Removes any optional parameters if no callers specifies it as an argument.
 * @param name The name of the function to optimize.
 * @param edges All the references to this name.
 */
private void tryEliminateOptionalArgs(Name name,
    List<DiGraphEdge<Name, Reference>> edges) {

  // Count the maximum number of arguments passed into this function all
  // all points of the program.
  int maxArgs = -1;

  for (DiGraphEdge<Name, Reference> refEdge : edges) {
    Reference ref = refEdge.getValue();
    Node call = ref.parent;

    if (isCallSite(ref)) {
      int numArgs = call.getChildCount() - 1;
      if (numArgs > maxArgs) {
        maxArgs = numArgs;
      }
    } // else this is a definition or a dereference, ignore it.
  }

  for (Definition definition : name.getDeclarations()) {
    eliminateParamsAfter(definition.getRValue(), maxArgs);
  }
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
public void enterScope(NodeTraversal t) {
  ControlFlowGraph<Node> cfg = t.getControlFlowGraph();

  for (DiGraphEdge<Node, Branch> s : cfg.getImplicitReturn().getInEdges()) {
    Node exitNode = s.getSource().getValue();
    if (!exitNode.isReturn() ||
        exitNode.getFirstChild() == null ||
        !exitNode.getFirstChild().isThis()) {
      badFunctionNodes.add(t.getScopeRoot());
      return;
    }
  }

  goodFunctionNodes.add(t.getScopeRoot());
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
@Override
public boolean apply(DiGraphEdge<Node, ControlFlowGraph.Branch> input) {
  // First skill all exceptions.
  Branch branch = input.getValue();
  if (branch == Branch.ON_EX) {
    return false;
  } else if (branch.isConditional()) {
    Node condition = NodeUtil.getConditionExpression(
        input.getSource().getValue());
    // TODO(user): We CAN make this bit smarter just looking at
    // constants. We DO have a full blown ReverseAbstractInterupter and
    // type system that can evaluate some impressions' boolean value but
    // for now we will keep this pass lightweight.
    if (condition != null) {
      TernaryValue val = NodeUtil.getImpureBooleanValue(condition);
      if (val != TernaryValue.UNKNOWN) {
        return val.toBoolean(true) == (Branch.ON_TRUE == branch);
      }
    }
  }
  return true;
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
private TypeEnv getInEnv(DiGraphNode<Node, ControlFlowGraph.Branch> dn) {
  List<DiGraphEdge<Node, ControlFlowGraph.Branch>> inEdges = dn.getInEdges();
  // True for code considered dead in the CFG
  if (inEdges.isEmpty()) {
    return getEntryTypeEnv();
  }
  if (inEdges.size() == 1) {
    return envs.get(inEdges.get(0));
  }

  Set<TypeEnv> envSet = new LinkedHashSet<>();
  for (DiGraphEdge<Node, ControlFlowGraph.Branch> de : inEdges) {
    TypeEnv env = envs.get(de);
    if (env != null) {
      envSet.add(env);
    }
  }
  if (envSet.isEmpty()) {
    return null;
  }
  return TypeEnv.join(envSet);
}
 

import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge; //导入依赖的package包/类
private TypeEnv getOutEnv(DiGraphNode<Node, ControlFlowGraph.Branch> dn) {
  List<DiGraphEdge<Node, ControlFlowGraph.Branch>> outEdges = dn.getOutEdges();
  if (outEdges.isEmpty()) {
    // This occurs when visiting a throw in the backward direction.
    checkArgument(dn.getValue().isThrow());
    return this.typeEnvFromDeclaredTypes;
  }
  if (outEdges.size() == 1) {
    return envs.get(outEdges.get(0));
  }
  Set<TypeEnv> envSet = new LinkedHashSet<>();
  for (DiGraphEdge<Node, ControlFlowGraph.Branch> de : outEdges) {
    TypeEnv env = envs.get(de);
    if (env != null) {
      envSet.add(env);
    }
  }
  checkState(!envSet.isEmpty());
  return TypeEnv.join(envSet);
}