scripts/undefsym.py

   1 #!/usr/bin/env python3
   2
   3 # Before a shared module's DSO is produced, a static library is built for it
   4 # and passed to this script.  The script generates -Wl,-u options to force
   5 # the inclusion of symbol from libqemuutil.a if the shared modules need them,
   6 # This is necessary because the modules may use functions not needed by the
   7 # executable itself, which would cause the function to not be linked in.
   8 # Then the DSO loading would fail because of the missing symbol.
   9
  10
  11 import sys
  12 import subprocess
  13
  14 def filter_lines_set(stdout, from_staticlib):
  15     linesSet = set()
  16     for line in stdout.splitlines():
  17         tokens = line.split(b' ')
  18         if len(tokens) >= 1:
  19             if len(tokens) > 1:
  20                 if from_staticlib and tokens[1] == b'U':
  21                     continue
  22                 if not from_staticlib and tokens[1] != b'U':
  23                     continue
  24             new_line = b'-Wl,-u,' + tokens[0]
  25             if not new_line in linesSet:
  26                 linesSet.add(new_line)
  27     return linesSet
  28
  29 def main(args):
  30     if len(args) <= 3:
  31         sys.exit(0)
  32
  33     nm = args[1]
  34     staticlib = args[2]
  35     pc = subprocess.run([nm, "-P", "-g", staticlib], stdout=subprocess.PIPE)
  36     if pc.returncode != 0:
  37         sys.exit(1)
  38     staticlib_syms = filter_lines_set(pc.stdout, True)
  39
  40     shared_modules = args[3:]
  41     pc = subprocess.run([nm, "-P", "-g"] + shared_modules, stdout=subprocess.PIPE)
  42     if pc.returncode != 0:
  43         sys.exit(1)
  44     modules_undef_syms = filter_lines_set(pc.stdout, False)
  45     lines = sorted(staticlib_syms.intersection(modules_undef_syms))
  46     sys.stdout.buffer.write(b'\n'.join(lines))
  47
  48 if __name__ == "__main__":
  49     main(sys.argv)