//  [java]
  Node parseInputs() {
    boolean devMode = options.devMode != DevMode.OFF;
    if (externsRoot != null) {
      externsRoot.detachChildren();
    }
    if (jsRoot != null) {
      jsRoot.detachChildren();
    }
    jsRoot = IR.block();
    jsRoot.setIsSyntheticBlock(true);
    externsRoot = IR.block();
    externsRoot.setIsSyntheticBlock(true);
    externAndJsRoot = IR.block(externsRoot, jsRoot);
    externAndJsRoot.setIsSyntheticBlock(true);
    if (options.tracer.isOn()) {
      tracker = new PerformanceTracker(jsRoot, options.tracer);
      addChangeHandler(tracker.getCodeChangeHandler());
    }
    Tracer tracer = newTracer("parseInputs");
    try {
      for (CompilerInput input : externs) {
        Node n = input.getAstRoot(this);
        if (hasErrors()) {
          return null;
        }
        externsRoot.addChildToBack(n);
      }
      if (options.transformAMDToCJSModules || options.processCommonJSModules) {
        processAMDAndCommonJSModules();
      }
      boolean staleInputs = false;
      if (options.dependencyOptions.needsManagement() &&
          !options.skipAllPasses &&
          options.closurePass) {
        for (CompilerInput input : inputs) {
          for (String provide : input.getProvides()) {
            getTypeRegistry().forwardDeclareType(provide);
          }
        }
        try {
          inputs =
              (moduleGraph == null ? new JSModuleGraph(modules) : moduleGraph)
              .manageDependencies(options.dependencyOptions, inputs);
          staleInputs = true;
        } catch (CircularDependencyException e) {
          report(JSError.make(
              JSModule.CIRCULAR_DEPENDENCY_ERROR, e.getMessage()));
          if (hasErrors()) {
            return null;
          }
        } catch (MissingProvideException e) {
          report(JSError.make(
              MISSING_ENTRY_ERROR, e.getMessage()));
          if (hasErrors()) {
            return null;
          }
        }
      }
      for (CompilerInput input : inputs) {
        Node n = input.getAstRoot(this);
        if (n == null) {
          continue;
        }
        if (n.getJSDocInfo() != null) {
          JSDocInfo info = n.getJSDocInfo();
          if (info.isExterns()) {
            externsRoot.addChildToBack(n);
            input.setIsExtern(true);
            input.getModule().remove(input);
            externs.add(input);
            staleInputs = true;
          } else if (info.isNoCompile()) {
            input.getModule().remove(input);
            staleInputs = true;
          }
        }
      }
      if (staleInputs) {
        fillEmptyModules(modules);
        rebuildInputsFromModules();
      }
      for (CompilerInput input : inputs) {
        Node n = input.getAstRoot(this);
        if (n == null) {
          continue;
        }
        if (devMode) {
          runSanityCheck();
          if (hasErrors()) {
            return null;
          }
        }
        if (options.sourceMapOutputPath != null ||
            options.nameReferenceReportPath != null) {
          SourceInformationAnnotator sia =
              new SourceInformationAnnotator(
                  input.getName(), options.devMode != DevMode.OFF);
          NodeTraversal.traverse(this, n, sia);
        }
        jsRoot.addChildToBack(n);
      }
      if (hasErrors()) {
        return null;
      }
      return externAndJsRoot;
    } finally {
      stopTracer(tracer, "parseInputs");
    }
  }