old_contents: var compiler = require('vue-template-compiler')
  var cache = require('lru-cache')(100)
  var hash = require('hash-sum')
  var SourceMapGenerator = require('source-map').SourceMapGenerator
  
  var splitRE = /\r?\n/g
  var emptyRE = /^(?:\/\/)?\s*$/
  
  module.exports = function (content, filename, needMap) {
    var cacheKey = hash(filename + content)
    // source-map cache busting for hot-reloadded modules
    var filenameWithHash = filename + '?' + cacheKey
    var output = cache.get(cacheKey)
    if (output) return output
    output = compiler.parseComponent(content, { pad: true })
    if (needMap) {
      if (output.script && !output.script.src) {
        output.script.map = generateSourceMap(
          filenameWithHash,
          content,
          output.script.content
        )
      }
      if (output.styles) {
        output.styles.forEach(style => {
          if (!style.src) {
            style.map = generateSourceMap(
              filenameWithHash,
              content,
              style.content
            )
          }
        })
      }
    }
    cache.set(cacheKey, output)
    return output
  }
  
  function generateSourceMap (filename, source, generated) {
    var map = new SourceMapGenerator()
    map.setSourceContent(filename, source)
    generated.split(splitRE).forEach((line, index) => {
      if (!emptyRE.test(line)) {
        map.addMapping({
          source: filename,
          original: {
            line: index + 1,
            column: 0
          },
          generated: {
            line: index + 1,
            column: 0
          }
        })
      }
    })
    return map.toJSON()
  }
  
new_contents: var compiler = require('vue-template-compiler')
  var cache = require('lru-cache')(100)
  var hash = require('hash-sum')
  var SourceMapGenerator = require('source-map').SourceMapGenerator
  
  var splitRE = /\r?\n/g
  var emptyRE = /^(?:\/\/)?\s*$/
  
  module.exports = function (content, filename, needMap) {
    var cacheKey = hash(filename + content)
    // source-map cache busting for hot-reloadded modules
    var filenameWithHash = filename + '?' + cacheKey
    var output = cache.get(cacheKey)
    if (output) return output
    output = compiler.parseComponent(content, { pad: 'line' })
    if (needMap) {
      if (output.script && !output.script.src) {
        output.script.map = generateSourceMap(
          filenameWithHash,
          content,
          output.script.content
        )
      }
      if (output.styles) {
        output.styles.forEach(style => {
          if (!style.src) {
            style.map = generateSourceMap(
              filenameWithHash,
              content,
              style.content
            )
          }
        })
      }
    }
    cache.set(cacheKey, output)
    return output
  }
  
  function generateSourceMap (filename, source, generated) {
    var map = new SourceMapGenerator()
    map.setSourceContent(filename, source)
    generated.split(splitRE).forEach((line, index) => {
      if (!emptyRE.test(line)) {
        map.addMapping({
          source: filename,
          original: {
            line: index + 1,
            column: 0
          },
          generated: {
            line: index + 1,
            column: 0
          }
        })
      }
    })
    return map.toJSON()
  }
  
subject: Update parser's call to parseComponent (#684)