memcheck_analyze.py

#!/usr/bin/env python
# Copyright (c) 2011 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# memcheck_analyze.py

''' Given a valgrind XML file, parses errors and uniques them.'''

import gdb_helper

from collections import defaultdict
import hashlib
import logging
import optparse
import os
import re
import subprocess
import sys
import time
from xml.dom.minidom import parse
from xml.parsers.expat import ExpatError

import common

# Global symbol table (yuck)
TheAddressTable = None

# These are regexps that define functions (using C++ mangled names)
# we don't want to see in stack traces while pretty printing
# or generating suppressions.
# Just stop printing the stack/suppression frames when the current one
# matches any of these.
_BORING_CALLERS = common.BoringCallers(mangled=True, use_re_wildcards=True)

def getTextOf(top_node, name):
  ''' Returns all text in all DOM nodes with a certain |name| that are children
  of |top_node|.
  '''

  text = ""
  for nodes_named in top_node.getElementsByTagName(name):
    text += "".join([node.data for node in nodes_named.childNodes
                     if node.nodeType == node.TEXT_NODE])
  return text

def getCDATAOf(top_node, name):
  ''' Returns all CDATA in all DOM nodes with a certain |name| that are children
  of |top_node|.
  '''

  text = ""
  for nodes_named in top_node.getElementsByTagName(name):
    text += "".join([node.data for node in nodes_named.childNodes
                     if node.nodeType == node.CDATA_SECTION_NODE])
  if (text == ""):
    return None
  return text

def shortenFilePath(source_dir, directory):
  '''Returns a string with the string prefix |source_dir| removed from
  |directory|.'''
  prefixes_to_cut = ["build/src/", "valgrind/coregrind/", "out/Release/../../"]

  if source_dir:
    prefixes_to_cut.append(source_dir)

  for p in prefixes_to_cut:
    index = directory.rfind(p)
    if index != -1:
      directory = directory[index + len(p):]

  return directory

# Constants that give real names to the abbreviations in valgrind XML output.
INSTRUCTION_POINTER = "ip"
OBJECT_FILE = "obj"
FUNCTION_NAME = "fn"
SRC_FILE_DIR = "dir"
SRC_FILE_NAME = "file"
SRC_LINE = "line"

def gatherFrames(node, source_dir):
  frames = []
  for frame in node.getElementsByTagName("frame"):
    frame_dict = {
      INSTRUCTION_POINTER : getTextOf(frame, INSTRUCTION_POINTER),
      OBJECT_FILE         : getTextOf(frame, OBJECT_FILE),
      FUNCTION_NAME       : getTextOf(frame, FUNCTION_NAME),
      SRC_FILE_DIR        : shortenFilePath(
          source_dir, getTextOf(frame, SRC_FILE_DIR)),
      SRC_FILE_NAME       : getTextOf(frame, SRC_FILE_NAME),
      SRC_LINE            : getTextOf(frame, SRC_LINE)
    }

    # Ignore this frame and all the following if it's a "boring" function.
    enough_frames = False
    for regexp in _BORING_CALLERS:
      if re.match("^%s$" % regexp, frame_dict[FUNCTION_NAME]):
        enough_frames = True
        break
    if enough_frames:
      break

    frames += [frame_dict]

    global TheAddressTable
    if TheAddressTable != None and frame_dict[SRC_LINE] == "":
      # Try using gdb
      TheAddressTable.Add(frame_dict[OBJECT_FILE],
                          frame_dict[INSTRUCTION_POINTER])
  return frames

class ValgrindError:
  ''' Takes a <DOM Element: error> node and reads all the data from it. A
  ValgrindError is immutable and is hashed on its pretty printed output.
  '''

  def __init__(self, source_dir, error_node, commandline, testcase):
    ''' Copies all the relevant information out of the DOM and into object
    properties.

    Args:
      error_node: The <error></error> DOM node we're extracting from.
      source_dir: Prefix that should be stripped from the <dir> node.
      commandline: The command that was run under valgrind
      testcase: The test case name, if known.
    '''

    # Valgrind errors contain one <what><stack> pair, plus an optional
    # <auxwhat><stack> pair, plus an optional <origin><what><stack></origin>,
    # plus (since 3.5.0) a <suppression></suppression> pair.
    # (Origin is nicely enclosed; too bad the other two aren't.)
    # The most common way to see all three in one report is
    # a syscall with a parameter that points to uninitialized memory, e.g.
    # Format:
    # <error>
    #   <unique>0x6d</unique>
    #   <tid>1</tid>
    #   <kind>SyscallParam</kind>
    #   <what>Syscall param write(buf) points to uninitialised byte(s)</what>
    #   <stack>
    #     <frame>
    #     ...
    #     </frame>
    #   </stack>
    #   <auxwhat>Address 0x5c9af4f is 7 bytes inside a block of ...</auxwhat>
    #   <stack>
    #     <frame>
    #     ...
    #     </frame>
    #   </stack>
    #   <origin>
    #   <what>Uninitialised value was created by a heap allocation</what>
    #   <stack>
    #     <frame>
    #     ...
    #     </frame>
    #   </stack>
    #   </origin>
    #   <suppression>
    #     <sname>insert_a_suppression_name_here</sname>
    #     <skind>Memcheck:Param</skind>
    #     <skaux>write(buf)</skaux>
    #     <sframe> <fun>__write_nocancel</fun> </sframe>
    #     ...
    #     <sframe> <fun>main</fun> </sframe>
    #     <rawtext>
    # <![CDATA[
    # {
    #    <insert_a_suppression_name_here>
    #    Memcheck:Param
    #    write(buf)
    #    fun:__write_nocancel
    #    ...
    #    fun:main
    # }
    # ]]>
    #     </rawtext>
    #   </suppression>
    # </error>
    #
    # Each frame looks like this:
    #  <frame>
    #    <ip>0x83751BC</ip>
    #    <obj>/data/dkegel/chrome-build/src/out/Release/base_unittests</obj>
    #    <fn>_ZN7testing8internal12TestInfoImpl7RunTestEPNS_8TestInfoE</fn>
    #    <dir>/data/dkegel/chrome-build/src/testing/gtest/src</dir>
    #    <file>gtest-internal-inl.h</file>
    #    <line>655</line>
    #  </frame>
    # although the dir, file, and line elements are missing if there is
    # no debug info.

    self._kind = getTextOf(error_node, "kind")
    self._backtraces = []
    self._suppression = None
    self._commandline = commandline
    self._testcase = testcase
    self._additional = []

    # Iterate through the nodes, parsing <what|auxwhat><stack> pairs.
    description = None
    for node in error_node.childNodes:
      if node.localName == "what" or node.localName == "auxwhat":
        description = "".join([n.data for n in node.childNodes
                              if n.nodeType == n.TEXT_NODE])
      elif node.localName == "xwhat":
        description = getTextOf(node, "text")
      elif node.localName == "stack":
        assert description
        self._backtraces.append([description, gatherFrames(node, source_dir)])
        description = None
      elif node.localName == "origin":
        description = getTextOf(node, "what")
        stack = node.getElementsByTagName("stack")[0]
        frames = gatherFrames(stack, source_dir)
        self._backtraces.append([description, frames])
        description = None
        stack = None
        frames = None
      elif description and node.localName != None:
        # The lastest description has no stack, e.g. "Address 0x28 is unknown"
        self._additional.append(description)
        description = None

      if node.localName == "suppression":
        self._suppression = getCDATAOf(node, "rawtext");

  def __str__(self):
    ''' Pretty print the type and backtrace(s) of this specific error,
        including suppression (which is just a mangled backtrace).'''
    output = ""
    output += "\n" # Make sure the ### is at the beginning of line.
    output += "### BEGIN MEMORY TOOL REPORT (error hash=#%016X#)\n" % \
        self.ErrorHash()
    if (self._commandline):
      output += self._commandline + "\n"

    output += self._kind + "\n"
    for backtrace in self._backtraces:
      output += backtrace[0] + "\n"
      filter = subprocess.Popen("c++filt -n", stdin=subprocess.PIPE,
                                stdout=subprocess.PIPE,
                                stderr=subprocess.STDOUT,
                                shell=True,
                                close_fds=True)
      buf = ""
      for frame in backtrace[1]:
        buf +=  (frame[FUNCTION_NAME] or frame[INSTRUCTION_POINTER]) + "\n"
      (stdoutbuf, stderrbuf) = filter.communicate(buf.encode('latin-1'))
      demangled_names = stdoutbuf.split("\n")

      i = 0
      for frame in backtrace[1]:
        output += ("  " + demangled_names[i])
        i = i + 1

        global TheAddressTable
        if TheAddressTable != None and frame[SRC_FILE_DIR] == "":
           # Try using gdb
           foo = TheAddressTable.GetFileLine(frame[OBJECT_FILE],
                                             frame[INSTRUCTION_POINTER])
           if foo[0] != None:
             output += (" (" + foo[0] + ":" + foo[1] + ")")
        elif frame[SRC_FILE_DIR] != "":
          output += (" (" + frame[SRC_FILE_DIR] + "/" + frame[SRC_FILE_NAME] +
                     ":" + frame[SRC_LINE] + ")")
        else:
          output += " (" + frame[OBJECT_FILE] + ")"
        output += "\n"

    for additional in self._additional:
      output += additional + "\n"

    assert self._suppression != None, "Your Valgrind doesn't generate " \
                                      "suppressions - is it too old?"

    if self._testcase:
      output += "The report came from the `%s` test.\n" % self._testcase
    output += "Suppression (error hash=#%016X#):\n" % self.ErrorHash()
    output += ("  For more info on using suppressions see "
               "http://dev.chromium.org/developers/tree-sheriffs/sheriff-details-chromium/memory-sheriff#TOC-Suppressing-memory-reports")

    # Widen suppression slightly to make portable between mac and linux
    # TODO(timurrrr): Oops, these transformations should happen
    # BEFORE calculating the hash!
    supp = self._suppression;
    supp = supp.replace("fun:_Znwj", "fun:_Znw*")
    supp = supp.replace("fun:_Znwm", "fun:_Znw*")
    supp = supp.replace("fun:_Znaj", "fun:_Zna*")
    supp = supp.replace("fun:_Znam", "fun:_Zna*")

    # Make suppressions even less platform-dependent.
    for sz in [1, 2, 4, 8]:
      supp = supp.replace("Memcheck:Addr%d" % sz, "Memcheck:Unaddressable")
      supp = supp.replace("Memcheck:Value%d" % sz, "Memcheck:Uninitialized")
    supp = supp.replace("Memcheck:Cond", "Memcheck:Uninitialized")

    # Split into lines so we can enforce length limits
    supplines = supp.split("\n")
    supp = None  # to avoid re-use

    # Truncate at line 26 (VG_MAX_SUPP_CALLERS plus 2 for name and type)
    # or at the first 'boring' caller.
    # (https://bugs.kde.org/show_bug.cgi?id=199468 proposes raising
    # VG_MAX_SUPP_CALLERS, but we're probably fine with it as is.)
    newlen = min(26, len(supplines));

    # Drop boring frames and all the following.
    enough_frames = False
    for frameno in range(newlen):
      for boring_caller in _BORING_CALLERS:
        if re.match("^ +fun:%s$" % boring_caller, supplines[frameno]):
          newlen = frameno
          enough_frames = True
          break
      if enough_frames:
        break
    if (len(supplines) > newlen):
      supplines = supplines[0:newlen]
      supplines.append("}")

    for frame in range(len(supplines)):
      # Replace the always-changing anonymous namespace prefix with "*".
      m = re.match("( +fun:)_ZN.*_GLOBAL__N_.*\.cc_" +
                   "[0-9a-fA-F]{8}_[0-9a-fA-F]{8}(.*)",
                   supplines[frame])
      if m:
        supplines[frame] = "*".join(m.groups())

    output += "\n".join(supplines) + "\n"
    output += "### END MEMORY TOOL REPORT (error hash=#%016X#)\n" % \
        self.ErrorHash()

    return output

  def UniqueString(self):
    ''' String to use for object identity. Don't print this, use str(obj)
    instead.'''
    rep = self._kind + " "
    for backtrace in self._backtraces:
      for frame in backtrace[1]:
        rep += frame[FUNCTION_NAME]

        if frame[SRC_FILE_DIR] != "":
          rep += frame[SRC_FILE_DIR] + "/" + frame[SRC_FILE_NAME]
        else:
          rep += frame[OBJECT_FILE]

    return rep

  # This is a device-independent hash identifying the suppression.
  # By printing out this hash we can find duplicate reports between tests and
  # different shards running on multiple buildbots
  def ErrorHash(self):
    return int(hashlib.md5(self.UniqueString()).hexdigest()[:16], 16)

  def __hash__(self):
    return hash(self.UniqueString())
  def __eq__(self, rhs):
    return self.UniqueString() == rhs

def log_is_finished(f, force_finish):
  f.seek(0)
  prev_line = ""
  while True:
    line = f.readline()
    if line == "":
      if not force_finish:
        return False
      # Okay, the log is not finished but we can make it up to be parseable:
      if prev_line.strip() in ["</error>", "</errorcounts>", "</status>"]:
        f.write("</valgrindoutput>\n")
        return True
      return False
    if '</valgrindoutput>' in line:
      # Valgrind often has garbage after </valgrindoutput> upon crash.
      f.truncate()
      return True
    prev_line = line

class MemcheckAnalyzer:
  ''' Given a set of Valgrind XML files, parse all the errors out of them,
  unique them and output the results.'''

  SANITY_TEST_SUPPRESSIONS = {
      "Memcheck sanity test 01 (memory leak).": 1,
      "Memcheck sanity test 02 (malloc/read left).": 1,
      "Memcheck sanity test 03 (malloc/read right).": 1,
      "Memcheck sanity test 04 (malloc/write left).": 1,
      "Memcheck sanity test 05 (malloc/write right).": 1,
      "Memcheck sanity test 06 (new/read left).": 1,
      "Memcheck sanity test 07 (new/read right).": 1,
      "Memcheck sanity test 08 (new/write left).": 1,
      "Memcheck sanity test 09 (new/write right).": 1,
      "Memcheck sanity test 10 (write after free).": 1,
      "Memcheck sanity test 11 (write after delete).": 1,
      "Memcheck sanity test 12 (array deleted without []).": 1,
      "Memcheck sanity test 13 (single element deleted with []).": 1,
      "Memcheck sanity test 14 (malloc/read uninit).": 1,
      "Memcheck sanity test 15 (new/read uninit).": 1,
  }

  # Max time to wait for memcheck logs to complete.
  LOG_COMPLETION_TIMEOUT = 180.0

  def __init__(self, source_dir, show_all_leaks=False, use_gdb=False):
    '''Create a parser for Memcheck logs.

    Args:
      source_dir: Path to top of source tree for this build
      show_all_leaks: Whether to show even less important leaks
      use_gdb: Whether to use gdb to resolve source filenames and line numbers
               in the report stacktraces
    '''
    self._source_dir = source_dir
    self._show_all_leaks = show_all_leaks
    self._use_gdb = use_gdb

    # Contains the set of unique errors
    self._errors = set()

    # Contains the time when the we started analyzing the first log file.
    # This variable is used to skip incomplete logs after some timeout.
    self._analyze_start_time = None


  def Report(self, files, testcase, check_sanity=False):
    '''Reads in a set of files and prints Memcheck report.

    Args:
      files: A list of filenames.
      check_sanity: if true, search for SANITY_TEST_SUPPRESSIONS
    '''
    # Beyond the detailed errors parsed by ValgrindError above,
    # the xml file contain records describing suppressions that were used:
    # <suppcounts>
    #  <pair>
    #    <count>28</count>
    #    <name>pango_font_leak_todo</name>
    #  </pair>
    #  <pair>
    #    <count>378</count>
    #    <name>bug_13243</name>
    #  </pair>
    # </suppcounts
    # Collect these and print them at the end.
    #
    # With our patch for https://bugs.kde.org/show_bug.cgi?id=205000 in,
    # the file also includes records of the form
    # <load_obj><obj>/usr/lib/libgcc_s.1.dylib</obj><ip>0x27000</ip></load_obj>
    # giving the filename and load address of each binary that was mapped
    # into the process.

    global TheAddressTable
    if self._use_gdb:
      TheAddressTable = gdb_helper.AddressTable()
    else:
      TheAddressTable = None
    cur_report_errors = set()
    suppcounts = defaultdict(int)
    badfiles = set()

    if self._analyze_start_time == None:
      self._analyze_start_time = time.time()
    start_time = self._analyze_start_time

    parse_failed = False
    for file in files:
      # Wait up to three minutes for valgrind to finish writing all files,
      # but after that, just skip incomplete files and warn.
      f = open(file, "r+")
      pid = re.match(".*\.([0-9]+)$", file)
      if pid:
        pid = pid.groups()[0]
      found = False
      running = True
      firstrun = True
      skip = False
      origsize = os.path.getsize(file)
      while (running and not found and not skip and
             (firstrun or
              ((time.time() - start_time) < self.LOG_COMPLETION_TIMEOUT))):
        firstrun = False
        f.seek(0)
        if pid:
          # Make sure the process is still running so we don't wait for
          # 3 minutes if it was killed. See http://crbug.com/17453
          ps_out = subprocess.Popen("ps p %s" % pid, shell=True,
                                    stdout=subprocess.PIPE).stdout
          if len(ps_out.readlines()) < 2:
            running = False
        else:
          skip = True
          running = False
        found = log_is_finished(f, False)
        if not running and not found:
          logging.warn("Valgrind process PID = %s is not running but its "
                       "XML log has not been finished correctly.\n"
                       "Make it up by adding some closing tags manually." % pid)
          found = log_is_finished(f, not running)
        if running and not found:
          time.sleep(1)
      f.close()
      if not found:
        badfiles.add(file)
      else:
        newsize = os.path.getsize(file)
        if origsize > newsize+1:
          logging.warn(str(origsize - newsize) +
                       " bytes of junk were after </valgrindoutput> in %s!" %
                       file)
        try:
          parsed_file = parse(file);
        except ExpatError, e:
          parse_failed = True
          logging.warn("could not parse %s: %s" % (file, e))
          lineno = e.lineno - 1
          context_lines = 5
          context_start = max(0, lineno - context_lines)
          context_end = lineno + context_lines + 1
          context_file = open(file, "r")
          for i in range(0, context_start):
            context_file.readline()
          for i in range(context_start, context_end):
            context_data = context_file.readline().rstrip()
            if i != lineno:
              logging.warn("  %s" % context_data)
            else:
              logging.warn("> %s" % context_data)
          context_file.close()
          continue
        if TheAddressTable != None:
          load_objs = parsed_file.getElementsByTagName("load_obj")
          for load_obj in load_objs:
            obj = getTextOf(load_obj, "obj")
            ip = getTextOf(load_obj, "ip")
            TheAddressTable.AddBinaryAt(obj, ip)

        commandline = None
        preamble = parsed_file.getElementsByTagName("preamble")[0];
        for node in preamble.getElementsByTagName("line"):
          if node.localName == "line":
            for x in node.childNodes:
              if x.nodeType == node.TEXT_NODE and "Command" in x.data:
                commandline = x.data
                break

        raw_errors = parsed_file.getElementsByTagName("error")
        for raw_error in raw_errors:
          # Ignore "possible" leaks for now by default.
          if (self._show_all_leaks or
              getTextOf(raw_error, "kind") != "Leak_PossiblyLost"):
            error = ValgrindError(self._source_dir,
                                  raw_error, commandline, testcase)
            if error not in cur_report_errors:
              # We haven't seen such errors doing this report yet...
              if error in self._errors:
                # ... but we saw it in earlier reports, e.g. previous UI test
                cur_report_errors.add("This error was already printed in "
                                      "some other test, see 'hash=#%016X#'" % \
                                      error.ErrorHash())
              else:
                # ... and we haven't seen it in other tests as well
                self._errors.add(error)
                cur_report_errors.add(error)

        suppcountlist = parsed_file.getElementsByTagName("suppcounts")
        if len(suppcountlist) > 0:
          suppcountlist = suppcountlist[0]
          for node in suppcountlist.getElementsByTagName("pair"):
            count = getTextOf(node, "count");
            name = getTextOf(node, "name");
            suppcounts[name] += int(count)

    if len(badfiles) > 0:
      logging.warn("valgrind didn't finish writing %d files?!" % len(badfiles))
      for file in badfiles:
        logging.warn("Last 20 lines of %s :" % file)
        os.system("tail -n 20 '%s' 1>&2" % file)

    if parse_failed:
      logging.error("FAIL! Couldn't parse Valgrind output file")
      return -2

    common.PrintUsedSuppressionsList(suppcounts)

    retcode = 0
    if cur_report_errors:
      logging.error("FAIL! There were %s errors: " % len(cur_report_errors))

      if TheAddressTable != None:
        TheAddressTable.ResolveAll()

      for error in cur_report_errors:
        logging.error(error)

      retcode = -1

    # Report tool's insanity even if there were errors.
    if check_sanity:
      remaining_sanity_supp = MemcheckAnalyzer.SANITY_TEST_SUPPRESSIONS
      for (name, count) in suppcounts.iteritems():
        # Workaround for http://crbug.com/334074
        if (name in remaining_sanity_supp and
            remaining_sanity_supp[name] <= count):
          del remaining_sanity_supp[name]
      if remaining_sanity_supp:
        logging.error("FAIL! Sanity check failed!")
        logging.info("The following test errors were not handled: ")
        for (name, count) in remaining_sanity_supp.iteritems():
          logging.info("  * %dx %s" % (count, name))
        retcode = -3

    if retcode != 0:
      return retcode

    logging.info("PASS! No errors found!")
    return 0


def _main():
  '''For testing only. The MemcheckAnalyzer class should be imported instead.'''
  parser = optparse.OptionParser("usage: %prog [options] <files to analyze>")
  parser.add_option("", "--source-dir",
                    help="path to top of source tree for this build"
                    "(used to normalize source paths in baseline)")

  (options, args) = parser.parse_args()
  if len(args) == 0:
    parser.error("no filename specified")
  filenames = args

  analyzer = MemcheckAnalyzer(options.source_dir, use_gdb=True)
  return analyzer.Report(filenames, None)


if __name__ == "__main__":
  sys.exit(_main())