text: # This Source Code Form is subject to the terms of the Mozilla Public
  # License, v. 2.0. If a copy of the MPL was not distributed with this
  # file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  '''expandlibs-exec.py applies expandlibs rules, and some more (see below) to
  a given command line, and executes that command line with the expanded
  arguments.
  
  With the --extract argument (useful for e.g. $(AR)), it extracts object files
  from static libraries (or use those listed in library descriptors directly).
  
  With the --uselist argument (useful for e.g. $(CC)), it replaces all object
  files with a list file. This can be used to avoid limitations in the length
  of a command line. The kind of list file format used depends on the
  EXPAND_LIBS_LIST_STYLE variable: 'list' for MSVC style lists (@file.list)
  or 'linkerscript' for GNU ld linker scripts.
  See https://bugzilla.mozilla.org/show_bug.cgi?id=584474#c59 for more details.
  
  With the --symbol-order argument, followed by a file name, it will add the
  relevant linker options to change the order in which the linker puts the
  symbols appear in the resulting binary. Only works for ELF targets.
  '''
  from __future__ import with_statement
  import sys
  import os
  from expandlibs import ExpandArgs, relativize, isObject, ensureParentDir, ExpandLibsDeps
  import expandlibs_config as conf
  from optparse import OptionParser
  import subprocess
  import tempfile
  import shutil
  import subprocess
  import re
  
  # The are the insert points for a GNU ld linker script, assuming a more
  # or less "standard" default linker script. This is not a dict because
  # order is important.
  SECTION_INSERT_BEFORE = [
    ('.text', '.fini'),
    ('.rodata', '.rodata1'),
    ('.data.rel.ro', '.dynamic'),
    ('.data', '.data1'),
  ]
  
  class ExpandArgsMore(ExpandArgs):
      ''' Meant to be used as 'with ExpandArgsMore(args) as ...: '''
      def __enter__(self):
          self.tmp = []
          return self
          
      def __exit__(self, type, value, tb):
          '''Automatically remove temporary files'''
          for tmp in self.tmp:
              if os.path.isdir(tmp):
                  shutil.rmtree(tmp, True)
              else:
                  os.remove(tmp)
  
      def extract(self):
          self[0:] = self._extract(self)
  
      def _extract(self, args):
          '''When a static library name is found, either extract its contents
          in a temporary directory or use the information found in the
          corresponding lib descriptor.
          '''
          ar_extract = conf.AR_EXTRACT.split()
          newlist = []
          for arg in args:
              if os.path.splitext(arg)[1] == conf.LIB_SUFFIX:
                  if os.path.exists(arg + conf.LIBS_DESC_SUFFIX):
                      newlist += self._extract(self._expand_desc(arg))
                  elif os.path.exists(arg) and len(ar_extract):
                      tmp = tempfile.mkdtemp(dir=os.curdir)
                      self.tmp.append(tmp)
                      subprocess.call(ar_extract + [os.path.abspath(arg)], cwd=tmp)
                      objs = []
                      for root, dirs, files in os.walk(tmp):
                          objs += [relativize(os.path.join(root, f)) for f in files if isObject(f)]
                      newlist += objs
                  else:
                      newlist += [arg]
              else:
                  newlist += [arg]
          return newlist
  
      def makelist(self):
          '''Replaces object file names with a temporary list file, using a
          list format depending on the EXPAND_LIBS_LIST_STYLE variable
          '''
          objs = [o for o in self if isObject(o)]
          if not len(objs): return
          fd, tmp = tempfile.mkstemp(suffix=".list",dir=os.curdir)
          if conf.EXPAND_LIBS_LIST_STYLE == "linkerscript":
              content = ['INPUT("%s")\n' % obj for obj in objs]
              ref = tmp
          elif conf.EXPAND_LIBS_LIST_STYLE == "list":
              content = ["%s\n" % obj for obj in objs]
              ref = "@" + tmp
          else:
              os.close(fd)
              os.remove(tmp)
              return
          self.tmp.append(tmp)
          f = os.fdopen(fd, "w")
          f.writelines(content)
          f.close()
          idx = self.index(objs[0])
          newlist = self[0:idx] + [ref] + [item for item in self[idx:] if item not in objs]
          self[0:] = newlist
  
      def _getFoldedSections(self):
          '''Returns a dict about folded sections.
          When section A and B are folded into section C, the dict contains:
          { 'A': 'C',
            'B': 'C',
            'C': ['A', 'B'] }'''
          if not conf.LD_PRINT_ICF_SECTIONS:
              return {}
  
          proc = subprocess.Popen(self + [conf.LD_PRINT_ICF_SECTIONS], stdout = subprocess.PIPE, stderr = subprocess.PIPE)
          (stdout, stderr) = proc.communicate()
          result = {}
          # gold's --print-icf-sections output looks like the following:
          # ld: ICF folding section '.section' in file 'file.o'into '.section' in file 'file.o'
          # In terms of words, chances are this will change in the future,
          # especially considering "into" is misplaced. Splitting on quotes
          # seems safer.
          for l in stderr.split('\n'):
              quoted = l.split("'")
              if len(quoted) > 5 and quoted[1] != quoted[5]:
                  result[quoted[1]] = quoted[5]
                  if quoted[5] in result:
                      result[quoted[5]].append(quoted[1])
                  else:
                      result[quoted[5]] = [quoted[1]]
          return result
  
      def _getOrderedSections(self, ordered_symbols):
          '''Given an ordered list of symbols, returns the corresponding list
          of sections following the order.'''
          if not conf.EXPAND_LIBS_ORDER_STYLE in ['linkerscript', 'section-ordering-file']:
              raise Exception('EXPAND_LIBS_ORDER_STYLE "%s" is not supported' % conf.EXPAND_LIBS_ORDER_STYLE)
          finder = SectionFinder([arg for arg in self if isObject(arg) or os.path.splitext(arg)[1] == conf.LIB_SUFFIX])
          folded = self._getFoldedSections()
          sections = set()
          ordered_sections = []
          for symbol in ordered_symbols:
              symbol_sections = finder.getSections(symbol)
              all_symbol_sections = []
              for section in symbol_sections:
                  if section in folded:
                      if isinstance(folded[section], str):
                          section = folded[section]
                      all_symbol_sections.append(section)
                      all_symbol_sections.extend(folded[section])
                  else:
                      all_symbol_sections.append(section)
              for section in all_symbol_sections:
                  if not section in sections:
                      ordered_sections.append(section)
                      sections.add(section)
          return ordered_sections
  
      def orderSymbols(self, order):
          '''Given a file containing a list of symbols, adds the appropriate
          argument to make the linker put the symbols in that order.'''
          with open(order) as file:
              sections = self._getOrderedSections([l.strip() for l in file.readlines() if l.strip()])
          split_sections = {}
          linked_sections = [s[0] for s in SECTION_INSERT_BEFORE]
          for s in sections:
              for linked_section in linked_sections:
                  if s.startswith(linked_section):
                      if linked_section in split_sections:
                          split_sections[linked_section].append(s)
                      else:
                          split_sections[linked_section] = [s]
                      break
          content = []
          # Order is important
          linked_sections = [s for s in linked_sections if s in split_sections]
  
          if conf.EXPAND_LIBS_ORDER_STYLE == 'section-ordering-file':
              option = '-Wl,--section-ordering-file,%s'
              content = sections
              for linked_section in linked_sections:
                  content.extend(split_sections[linked_section])
                  content.append('%s.*' % linked_section)
                  content.append(linked_section)
  
          elif conf.EXPAND_LIBS_ORDER_STYLE == 'linkerscript':
              option = '-Wl,-T,%s'
              section_insert_before = dict(SECTION_INSERT_BEFORE)
              for linked_section in linked_sections:
                  content.append('SECTIONS {')
                  content.append('  %s : {' % linked_section)
                  content.extend('    *(%s)' % s for s in split_sections[linked_section])
                  content.append('  }')
                  content.append('}')
                  content.append('INSERT BEFORE %s' % section_insert_before[linked_section])
          else:
              raise Exception('EXPAND_LIBS_ORDER_STYLE "%s" is not supported' % conf.EXPAND_LIBS_ORDER_STYLE)
  
          fd, tmp = tempfile.mkstemp(dir=os.curdir)
          f = os.fdopen(fd, "w")
          f.write('\n'.join(content)+'\n')
          f.close()
          self.tmp.append(tmp)
          self.append(option % tmp)
  
  class SectionFinder(object):
      '''Instances of this class allow to map symbol names to sections in
      object files.'''
  
      def __init__(self, objs):
          '''Creates an instance, given a list of object files.'''
          if not conf.EXPAND_LIBS_ORDER_STYLE in ['linkerscript', 'section-ordering-file']:
              raise Exception('EXPAND_LIBS_ORDER_STYLE "%s" is not supported' % conf.EXPAND_LIBS_ORDER_STYLE)
          self.mapping = {}
          for obj in objs:
              if not isObject(obj) and os.path.splitext(obj)[1] != conf.LIB_SUFFIX:
                  raise Exception('%s is not an object nor a static library' % obj)
              for symbol, section in SectionFinder._getSymbols(obj):
                  sym = SectionFinder._normalize(symbol)
                  if sym in self.mapping:
                      if not section in self.mapping[sym]:
                          self.mapping[sym].append(section)
                  else:
                      self.mapping[sym] = [section]
  
      def getSections(self, symbol):
          '''Given a symbol, returns a list of sections containing it or the
          corresponding thunks. When the given symbol is a thunk, returns the
          list of sections containing its corresponding normal symbol and the
          other thunks for that symbol.'''
          sym = SectionFinder._normalize(symbol)
          if sym in self.mapping:
              return self.mapping[sym]
          return []
  
      @staticmethod
      def _normalize(symbol):
          '''For normal symbols, return the given symbol. For thunks, return
          the corresponding normal symbol.'''
          if re.match('^_ZThn[0-9]+_', symbol):
              return re.sub('^_ZThn[0-9]+_', '_Z', symbol)
          return symbol
  
      @staticmethod
      def _getSymbols(obj):
          '''Returns a list of (symbol, section) contained in the given object
          file.'''
          proc = subprocess.Popen(['objdump', '-t', obj], stdout = subprocess.PIPE, stderr = subprocess.PIPE)
          (stdout, stderr) = proc.communicate()
          syms = []
          for line in stdout.splitlines():
              # Each line has the following format:
              # <addr> [lgu!][w ][C ][W ][Ii ][dD ][FfO ] <section>\t<length> <symbol>
              tmp = line.split(' ',1)
              # This gives us ["<addr>", "[lgu!][w ][C ][W ][Ii ][dD ][FfO ] <section>\t<length> <symbol>"]
              # We only need to consider cases where "<section>\t<length> <symbol>" is present,
              # and where the [FfO] flag is either F (function) or O (object).
              if len(tmp) > 1 and len(tmp[1]) > 6 and tmp[1][6] in ['O', 'F']:
                  tmp = tmp[1][8:].split()
                  # That gives us ["<section>","<length>", "<symbol>"]
                  syms.append((tmp[-1], tmp[0]))
          return syms
  
  def main():
      parser = OptionParser()
      parser.add_option("--depend", dest="depend", metavar="FILE",
          help="generate dependencies for the given execution and store it in the given file")
      parser.add_option("--target", dest="target", metavar="FILE",
          help="designate the target for dependencies")
      parser.add_option("--extract", action="store_true", dest="extract",
          help="when a library has no descriptor file, extract it first, when possible")
      parser.add_option("--uselist", action="store_true", dest="uselist",
          help="use a list file for objects when executing a command")
      parser.add_option("--verbose", action="store_true", dest="verbose",
          help="display executed command and temporary files content")
      parser.add_option("--symbol-order", dest="symbol_order", metavar="FILE",
          help="use the given list of symbols to order symbols in the resulting binary when using with a linker")
  
      (options, args) = parser.parse_args()
  
      if not options.target:
          options.depend = False
      if options.depend:
          deps = ExpandLibsDeps(args)
          # Filter out common command wrappers
          while os.path.basename(deps[0]) in ['ccache', 'distcc']:
              deps.pop(0)
          # Remove command
          deps.pop(0)
      with ExpandArgsMore(args) as args:
          if options.extract:
              args.extract()
          if options.symbol_order:
              args.orderSymbols(options.symbol_order)
          if options.uselist:
              args.makelist()
  
          if options.verbose:
              print >>sys.stderr, "Executing: " + " ".join(args)
              for tmp in [f for f in args.tmp if os.path.isfile(f)]:
                  print >>sys.stderr, tmp + ":"
                  with open(tmp) as file:
                      print >>sys.stderr, "".join(["    " + l for l in file.readlines()])
              sys.stderr.flush()
          ret = subprocess.call(args)
          if ret:
              exit(ret)
      if not options.depend:
          return
      ensureParentDir(options.depend)
      with open(options.depend, 'w') as depfile:
          depfile.write("%s : %s\n" % (options.target, ' '.join(dep for dep in deps if os.path.isfile(dep) and dep != options.target)))
  
  
  if __name__ == '__main__':
      main()
  