#!/usr/bin/env vpython
# Copyright 2017 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.

"""Lists all the reached symbols from an instrumentation dump."""

import argparse
import collections
import logging
import operator
import os
import sys

_SRC_PATH = os.path.abspath(os.path.join(
    os.path.dirname(__file__), os.pardir, os.pardir))
path = os.path.join(_SRC_PATH, 'tools', 'cygprofile')
sys.path.append(path)
import cygprofile_utils
import symbol_extractor


def _Median(items):
  if not items:
    return None
  sorted_items = sorted(items)
  if len(sorted_items) & 1:
    return sorted_items[len(sorted_items)/2]
  else:
    return (sorted_items[len(sorted_items)/2 - 1] +
            sorted_items[len(sorted_items)/2]) / 2


class SymbolOffsetProcessor(object):
  """Utility for processing symbols in binaries.

  This class is used to translate between general offsets into a binary and the
  starting offset of symbols in the binary. Because later phases in orderfile
  generation have complicated strategies for resolving multiple symbols that map
  to the same binary offset, this class is concerned with locating a symbol
  containing a binary offset. If such a symbol exists, the start offset will be
  unique, even when there are multiple symbol names at the same location in the
  binary.

  In the function names below, "dump" is used to refer to arbitrary offsets in a
  binary (eg, from a profiling run), while "offset" refers to a symbol
  offset. The dump offsets are relative to the start of text, as produced by
  orderfile_instrumentation.cc.

  This class manages expensive operations like extracting symbols, so that
  higher-level operations can be done in different orders without the caller
  managing all the state.
  """

  def __init__(self, binary_filename):
    self._binary_filename = binary_filename
    self._symbol_infos = None
    self._name_to_symbol = None
    self._offset_to_primary = None
    self._offset_to_symbols = None
    self._offset_to_symbol_info = None

  def SymbolInfos(self):
    """The symbols associated with this processor's binary.

    The symbols are ordered by offset.

    Returns:
      [symbol_extractor.SymbolInfo]
    """
    if self._symbol_infos is None:
      self._symbol_infos = symbol_extractor.SymbolInfosFromBinary(
          self._binary_filename)
      self._symbol_infos.sort(key=lambda s: s.offset)
      logging.info('%d symbols from %s',
                   len(self._symbol_infos), self._binary_filename)
    return self._symbol_infos

  def NameToSymbolMap(self):
    """Map symbol names to their full information.

    Returns:
      {symbol name (str): symbol_extractor.SymbolInfo}
    """
    if self._name_to_symbol is None:
      self._name_to_symbol = {s.name: s for s in self.SymbolInfos()}
    return self._name_to_symbol

  def OffsetToPrimaryMap(self):
    """The map of a symbol offset in this binary to its primary symbol.

    Several symbols can be aliased to the same address, through ICF. This
    returns the first one. The order is consistent for a given binary, as it's
    derived from the file layout. We assert that all aliased symbols are the
    same size.

    Returns:
      {offset (int): primary (symbol_extractor.SymbolInfo)}
    """
    if self._offset_to_primary is None:
      self._offset_to_primary = {}
      for s in self.SymbolInfos():
        if s.offset not in self._offset_to_primary:
          self._offset_to_primary[s.offset] = s
        else:
          curr = self._offset_to_primary[s.offset]
          if curr.size != s.size:
            assert curr.size == 0 or s.size == 0, (
                'Nonzero size mismatch between {} and {}'.format(
                    curr.name, s.name))
            # Upgrade to a symbol with nonzero size, otherwise don't change
            # anything so that we use the earliest nonzero-size symbol.
            if curr.size == 0 and s.size != 0:
              self._offset_to_primary[s.offset] = s

    return self._offset_to_primary

  def OffsetToSymbolsMap(self):
    """Map offsets to the set of matching symbols.

    Unlike OffsetToPrimaryMap, this is a 1-to-many mapping.

    Returns;
      {offset (int): [symbol_extractor.SymbolInfo]}
    """
    if self._offset_to_symbols is None:
      self._offset_to_symbols = symbol_extractor.GroupSymbolInfosByOffset(
          self.SymbolInfos())
    return self._offset_to_symbols

  def GetOrderedSymbols(self, offsets):
    """Maps a list of offsets to symbol names, retaining ordering.

    The symbol name is the primary symbol. This also deals with thumb
    instruction (which have odd offsets).

    Args::
      offsets (int iterable) a set of offsets.

    Returns
      [str] list of symbol names.
    """
    symbols = []
    not_found = 0
    for o in offsets:
      if o in self.OffsetToPrimaryMap():
        symbols.append(self.OffsetToPrimaryMap()[o].name)
      elif o % 2 and (o - 1) in self.OffsetToPrimaryMap():
        symbols.append(self.OffsetToPrimaryMap()[o - 1].name)
      else:
        not_found += 1
    if not_found:
      logging.warning('%d offsets do not have matching symbol', not_found)
    return symbols

  def SymbolsSize(self, symbols):
    """Computes the total size of a set of symbol names.

    Args:
      offsets (str iterable) a set of symbols.

    Returns
      int The sum of the primary size of the offsets.
    """
    name_map = self.NameToSymbolMap()
    return sum(name_map[sym].size for sym in symbols)

  def GetReachedOffsetsFromDump(self, dump):
    """Find the symbol offsets from a list of binary offsets.

    The dump is a list offsets into a .text section. This finds the symbols
    which contain the dump offsets, and returns their offsets. Note that while
    usually a symbol offset corresponds to a single symbol, in some cases
    several symbols will map to the same offset. For that reason this function
    returns only the offset list. See cyglog_to_orderfile.py for computing more
    information about symbols.

    Args:
     dump: (int iterable) Dump offsets, for example as returned by MergeDumps().

    Returns:
      [int] Reached symbol offsets.
    """
    reached_offsets = []
    already_seen = set()
    def update(_, symbol_offset):
      if symbol_offset is None or symbol_offset in already_seen:
        return
      reached_offsets.append(symbol_offset)
      already_seen.add(symbol_offset)
    self._TranslateReachedOffsetsFromDump(dump, lambda x: x, update)
    return reached_offsets

  def MatchSymbolNames(self, symbol_names):
    """Find the symbols in this binary which match a list of symbols.

    Args:
      symbol_names (str iterable) List of symbol names.

    Returns:
      [symbol_extractor.SymbolInfo] Symbols in this binary matching the names.
    """
    our_symbol_names = set(s.name for s in self.SymbolInfos())
    matched_names = our_symbol_names.intersection(set(symbol_names))
    return [self.NameToSymbolMap()[n] for n in matched_names]

  def TranslateAnnotatedSymbolOffsets(self, annotated_offsets):
    """Merges offsets across run groups and translates to symbol offsets.

    Like GetReachedOffsetsFromDump, but works with AnnotatedOffsets.

    Args:
      annotated_offsets (AnnotatedOffset iterable) List of annotated offsets,
        eg from ProfileManager.GetAnnotatedOffsets(). This will be mutated to
        translate raw offsets to symbol offsets.
    """
    self._TranslateReachedOffsetsFromDump(
        annotated_offsets,
        lambda o: o.Offset(),
        lambda o, symbol_offset: o.SetOffset(symbol_offset))

  def _TranslateReachedOffsetsFromDump(self, items, get, update):
    """Translate raw binary offsets to symbol offsets.

    See GetReachedOffsetsFromDump for details. This version calls
    |get(i)| on each element |i| of |items|, then calls
    |update(i, symbol_offset)| with the updated offset. If the offset is not
    found, update will be called with None.

    Args:
      items: (iterable) Items containing offsets.
      get: (lambda item) As described above.
      update: (lambda item, int) As described above.
    """
    dump_offset_to_symbol_info = self.GetDumpOffsetToSymbolInfo()
    for i in items:
      dump_offset = get(i)
      idx = dump_offset / 2
      assert dump_offset >= 0 and idx < len(dump_offset_to_symbol_info), (
          'Dump offset out of binary range')
      symbol_info = dump_offset_to_symbol_info[idx]
      assert symbol_info, ('A return address (offset = 0x{:08x}) does not map '
          'to any symbol'.format(dump_offset))
      update(i, symbol_info.offset)

  def GetDumpOffsetToSymbolInfo(self):
    """Computes an array mapping each word in .text to a symbol.

    Returns:
      [symbol_extractor.SymbolInfo or None] For every 4 bytes of the .text
        section, maps it to a symbol, or None.
    """
    if self._offset_to_symbol_info is None:
      start_syms = [s for s in self.SymbolInfos()
                    if s.name == cygprofile_utils.START_OF_TEXT_SYMBOL]
      assert len(start_syms) == 1, 'Can\'t find unique start of text symbol'
      start_of_text = start_syms[0].offset
      max_offset = max(s.offset + s.size for s in self.SymbolInfos())
      text_length_halfwords = (max_offset - start_of_text) / 2
      self._offset_to_symbol_info = [None] * text_length_halfwords
      for sym in self.SymbolInfos():
        offset = sym.offset - start_of_text
        assert offset >= 0, ('Unexpected symbol before the start of text. '
                             'Has the linker script broken?')
        # The low bit of offset may be set to indicate a thumb instruction. The
        # actual offset is still halfword aligned and so the low bit may be
        # safely ignored in the division by two below.
        for i in range(offset / 2, (offset + sym.size) / 2):
          assert i < text_length_halfwords
          other_symbol = self._offset_to_symbol_info[i]
          # There may be overlapping symbols, for example fancy
          # implementations for __ltsf2 and __gtsf2 (merging common tail
          # code). In this case, keep the one that started first.
          if other_symbol is None or other_symbol.offset > sym.offset:
            self._offset_to_symbol_info[i] = sym
    return self._offset_to_symbol_info


class ProfileManager(object):
  """Manipulates sets of profiles.

  A "profile set" refers to a set of data from an instrumented version of chrome
  that will be processed together, usually to produce a single orderfile. A
  "run" refers to a session of chrome, visiting several pages and thus
  comprising a browser process and at least one renderer process. A "dump"
  refers to the instrumentation in chrome writing out offsets of instrumented
  functions. There may be several dumps per run, for example one describing
  chrome startup and a second describing steady-state page interaction. Each
  process in a run produces one file per dump.

  These dump files have a timestamp of the dump time. Each process produces its
  own timestamp, but the dumps from each process occur very near in time to each
  other (< 1 second). If there are several dumps per run, each set of dumps is
  marked by a "phase" in the filename which is consistent across processes. For
  example the dump for the startup could be phase 0 and then the steady-state
  would be labeled phase 1.

  We assume the files are named like
  profile-hitmap-PROCESS-PID-TIMESTAMP.SUFFIX_PHASE, where PROCESS is a possibly
  empty string, PID is the process id, TIMESTAMP is in nanoseconds, SUFFIX is
  string without dashes, PHASE is an integer numbering the phases as 0, 1, 2...,
  and the only dot is the one between TIMESTAMP and SUFFIX.

  This manager supports several configurations of dumps.

  * A single dump from a single run. These files are merged together to produce
    a single dump without regard for browser versus renderer methods.

  * Several phases of dumps from a single run. Files are grouped by phase as
    described above.

  * Several phases of dumps from multiple runs from a set of telemetry
    benchmarks. The timestamp is used to distinguish each run because each
    benchmark takes < 10 seconds to run but there are > 50 seconds of setup
    time. This files can be grouped into run sets that are within 30 seconds of
    each other. Each run set is then grouped into phases as before.
  """
  class AnnotatedOffset(object):
    """Describes an offset with how it appeared in a profile set.

    Each offset is annotated with the phase and process that it appeared in, and
    can report how often it occurred in a specific phase and process.
    """
    def __init__(self, offset):
      self._offset = offset
      self._count = {}

    def __str__(self):
      return '{}: {}'.format(self._offset, self._count)

    def __eq__(self, other):
      if other is None:
        return False
      return (self._offset == other._offset and
              self._count == other._count)

    def Increment(self, phase, process):
      key = (phase, process)
      self._count[key] = self._count.setdefault(key, 0) + 1

    def Count(self, phase, process):
      return self._count.get((phase, process), 0)

    def Processes(self):
      return set(k[1] for k in self._count.iterkeys())

    def Phases(self):
      return set(k[0] for k in self._count.iterkeys())

    def Offset(self):
      return self._offset

    def SetOffset(self, o):
      self._offset = o

  class _RunGroup(object):
    RUN_GROUP_THRESHOLD_NS = 30e9

    def __init__(self):
      self._filenames = []

    def Filenames(self, phase=None):
      if phase is None:
        return self._filenames
      return [f for f in self._filenames
              if ProfileManager._Phase(f) == phase]

    def Add(self, filename):
      self._filenames.append(filename)

    def IsCloseTo(self, filename):
      run_group_ts = _Median(
          [ProfileManager._Timestamp(f) for f in self._filenames])
      return abs(ProfileManager._Timestamp(filename) -
                 run_group_ts) < self.RUN_GROUP_THRESHOLD_NS

  def __init__(self, filenames):
    """Initialize a ProfileManager.

    Args:
      filenames ([str]): List of filenames describe the profile set.
    """
    self._filenames = sorted(filenames, key=self._Timestamp)
    self._run_groups = None

  def GetPhases(self):
    """Return the set of phases of all orderfiles.

    Returns:
      set(int)
    """
    return set(self._Phase(f) for f in self._filenames)

  def GetMergedOffsets(self, phase=None):
    """Merges files, as if from a single dump.

    Args:
      phase (int, optional) If present, restrict to this phase.

    Returns:
      [int] Ordered list of reached offsets. Each offset only appears
      once in the output, in the order of the first dump that contains it.
    """
    if phase is None:
      return self._GetOffsetsForGroup(self._filenames)
    return self._GetOffsetsForGroup(f for f in self._filenames
                                    if self._Phase(f) == phase)

  def GetAnnotatedOffsets(self):
    """Merges offsets across run groups and annotates each one.

    Returns:
      [AnnotatedOffset]
    """
    offset_map = {}  # offset int -> AnnotatedOffset
    for g in self._GetRunGroups():
      for f in g:
        phase = self._Phase(f)
        process = self._ProcessName(f)
        for offset in self._ReadOffsets(f):
          offset_map.setdefault(offset, self.AnnotatedOffset(offset)).Increment(
              phase, process)
    return offset_map.values()

  def GetProcessOffsetLists(self):
    """Returns all symbol offsets lists, grouped by process."""
    offsets_by_process = collections.defaultdict(list)
    for f in self._filenames:
      offsets_by_process[self._ProcessName(f)].append(self._ReadOffsets(f))
    return offsets_by_process

  def GetRunGroupOffsets(self, phase=None):
    """Merges files from each run group and returns offset list for each.

    Args:
      phase (int, optional) If present, restrict to this phase.

    Returns:
     [ [int] ] List of offsets lists, each as from GetMergedOffsets.
    """
    return [self._GetOffsetsForGroup(g) for g in self._GetRunGroups(phase)]

  def _GetOffsetsForGroup(self, filenames):
    dumps = [self._ReadOffsets(f) for f in filenames]
    seen_offsets = set()
    result = []
    for dump in dumps:
      for offset in dump:
        if offset not in seen_offsets:
          result.append(offset)
          seen_offsets.add(offset)
    return result

  def _GetRunGroups(self, phase=None):
    if self._run_groups is None:
      self._ComputeRunGroups()
    return [g.Filenames(phase) for g in self._run_groups]

  @classmethod
  def _ProcessName(cls, filename):
    # The filename starts with 'profile-hitmap-' and ends with
    # '-PID-TIMESTAMP.txt_X'. Anything in between is the process name. The
    # browser has an empty process name, which is insterted here.
    process_name_parts = os.path.basename(filename).split('-')[2:-2]
    if not process_name_parts:
      return 'browser'
    return '-'.join(process_name_parts)

  @classmethod
  def _Timestamp(cls, filename):
    dash_index = filename.rindex('-')
    dot_index = filename.rindex('.')
    return int(filename[dash_index+1:dot_index])

  @classmethod
  def _Phase(cls, filename):
    return int(filename.split('_')[-1])

  def _ReadOffsets(self, filename):
    return [int(x.strip()) for x in open(filename)]

  def _ComputeRunGroups(self):
    self._run_groups = []
    for f in self._filenames:
      for g in self._run_groups:
        if g.IsCloseTo(f):
          g.Add(f)
          break
      else:
        g = self._RunGroup()
        g.Add(f)
        self._run_groups.append(g)

    # Some sanity checks on the run groups.
    assert self._run_groups
    if len(self._run_groups) < 5:
      return  # Small runs have too much variance for testing.
    sizes = map(lambda g: len(g.Filenames()), self._run_groups)
    avg_size = sum(sizes) / len(self._run_groups)
    num_outliers = len([s for s in sizes
                        if s > 1.5 * avg_size or s < 0.75 * avg_size])
    expected_outliers = 0.1 * len(self._run_groups)
    assert num_outliers < expected_outliers, (
        'Saw {} outliers instead of at most {} for average of {}'.format(
            num_outliers, expected_outliers, avg_size))


def GetReachedOffsetsFromDumpFiles(dump_filenames, library_filename):
  """Produces a list of symbol offsets reached by the dumps.

  Args:
    dump_filenames (str iterable) A list of dump filenames.
    library_filename (str) The library file which the dumps refer to.

  Returns:
    [int] A list of symbol offsets. This order of symbol offsets produced is
      given by the deduplicated order of offsets found in dump_filenames (see
      also MergeDumps().
  """
  dump = ProfileManager(dump_filenames).GetMergedOffsets()
  if not dump:
    logging.error('Empty dump, cannot continue: %s', '\n'.join(dump_filenames))
    return None
  logging.info('Reached offsets = %d', len(dump))
  processor = SymbolOffsetProcessor(library_filename)
  return processor.GetReachedOffsetsFromDump(dump)


def CreateArgumentParser():
  """Returns an ArgumentParser."""
  parser = argparse.ArgumentParser(description='Outputs reached symbols')
  parser.add_argument('--instrumented-build-dir', type=str,
                      help='Path to the instrumented build', required=True)
  parser.add_argument('--build-dir', type=str, help='Path to the build dir',
                      required=True)
  parser.add_argument('--dumps', type=str, help='A comma-separated list of '
                      'files with instrumentation dumps', required=True)
  parser.add_argument('--output', type=str, help='Output filename',
                      required=True)
  parser.add_argument('--offsets-output', type=str,
                      help='Output filename for the symbol offsets',
                      required=False, default=None)
  parser.add_argument('--library-name', default='libchrome.so',
                      help=('Chrome shared library name (usually libchrome.so '
                            'or libmonochrome.so'))
  return parser


def main():
  logging.basicConfig(level=logging.INFO)
  parser = CreateArgumentParser()
  args = parser.parse_args()
  logging.info('Merging dumps')
  dump_files = args.dumps.split(',')
  profile_manager = ProfileManager(dump_files)
  profile_manager.SortByTimestamp()
  dumps = profile_manager.GetMergedOffsets()

  instrumented_native_lib = os.path.join(args.instrumented_build_dir,
                                         'lib.unstripped', args.library_name)
  regular_native_lib = os.path.join(args.build_dir,
                                    'lib.unstripped', args.library_name)

  instrumented_processor = SymbolOffsetProcessor(instrumented_native_lib)

  reached_offsets = instrumented_processor.GetReachedOffsetsFromDumps(dumps)
  if args.offsets_output:
    with file(args.offsets_output, 'w') as f:
      f.write('\n'.join(map(str, reached_offsets)))
  logging.info('Reached Offsets = %d', len(reached_offsets))

  primary_map = instrumented_processor.OffsetToPrimaryMap()
  reached_primary_symbols = set(
      primary_map[offset] for offset in reached_offsets)
  logging.info('Reached symbol names = %d', len(reached_primary_symbols))

  regular_processor = SymbolOffsetProcessor(regular_native_lib)
  matched_in_regular_build = regular_processor.MatchSymbolNames(
      s.name for s in reached_primary_symbols)
  logging.info('Matched symbols = %d', len(matched_in_regular_build))
  total_size = sum(s.size for s in matched_in_regular_build)
  logging.info('Total reached size = %d', total_size)

  with open(args.output, 'w') as f:
    for s in matched_in_regular_build:
      f.write(s.name + '\n')


if __name__ == '__main__':
  main()
