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) >= 2:
  19             if from_staticlib and tokens[1] == b'U':
  20                 continue
  21             if not from_staticlib and tokens[1] != b'U':
  22                 continue
  23             new_line = b'-Wl,-u,' + tokens[0]
  24             if not new_line in linesSet:
  25                 linesSet.add(new_line)
  26     return linesSet
  27
  28 def main(args):
  29     if len(args) <= 3:
  30         sys.exit(0)
  31
  32     nm = args[1]
  33     staticlib = args[2]
  34     pc = subprocess.run([nm, "-P", "-g", staticlib], stdout=subprocess.PIPE)
  35     if pc.returncode != 0:
  36         sys.exit(1)
  37     staticlib_syms = filter_lines_set(pc.stdout, True)
  38
  39     shared_modules = args[3:]
  40     pc = subprocess.run([nm, "-P", "-g"] + shared_modules, stdout=subprocess.PIPE)
  41     if pc.returncode != 0:
  42         sys.exit(1)
  43     modules_undef_syms = filter_lines_set(pc.stdout, False)
  44     lines = sorted(staticlib_syms.intersection(modules_undef_syms))
  45     sys.stdout.buffer.write(b'\n'.join(lines))
  46
  47 if __name__ == "__main__":
  48     main(sys.argv)