#! /usr/bin/env python3

# objgraph
#
# Read "nm -o" input of a set of libraries or modules and print various
# interesting listings, such as:
#
# - which names are used but not defined in the set (and used where),
# - which names are defined in the set (and where),
# - which modules use which other modules,
# - which modules are used by which other modules.
#
# Usage: objgraph [-cdu] [file] ...
# -c: print callers per objectfile
# -d: print callees per objectfile
# -u: print usage of undefined symbols
# If none of -cdu is specified, all are assumed.
# Use "nm -o" to generate the input
# e.g.: nm -o /lib/libc.a | objgraph


import sys
import os
import getopt
import re

# Types of symbols.
#
definitions = 'TRGDSBAEC'
externals = 'UV'
ignore = 'Nntrgdsbavuc'

# Regular expression to parse "nm -o" output.
#
matcher = re.compile('(.*):\t?........ (.) (.*)$')

# Store "item" in "dict" under "key".
# The dictionary maps keys to lists of items.
# If there is no list for the key yet, it is created.
#
def store(dict, key, item):
 if key in dict:
 dict[key].append(item)
 else:
 dict[key] = [item]

# Return a flattened version of a list of strings: the concatenation
# of its elements with intervening spaces.
#
def flat(list):
 s = ''
 for item in list:
 s = s + ' ' + item
 return s[1:]

# Global variables mapping defined/undefined names to files and back.
#
file2undef = {}
def2file = {}
file2def = {}
undef2file = {}

# Read one input file and merge the data into the tables.
# Argument is an open file.
#
def readinput(fp):
 while 1:
 s = fp.readline()
 if not s:
 break
 # If you get any output from this line,
 # it is probably caused by an unexpected input line:
 if matcher.search(s) < 0: s; continue # Shouldn't happen
 (ra, rb), (r1a, r1b), (r2a, r2b), (r3a, r3b) = matcher.regs[:4]
 fn, name, type = s[r1a:r1b], s[r3a:r3b], s[r2a:r2b]
 if type in definitions:
 store(def2file, name, fn)
 store(file2def, fn, name)
 elif type in externals:
 store(file2undef, fn, name)
 store(undef2file, name, fn)
 elif not type in ignore:
 print(fn + ':' + name + ': unknown type ' + type)

# Print all names that were undefined in some module and where they are
# defined.
#
def printcallee():
 flist = sorted(file2undef.keys())
 for filename in flist:
 print(filename + ':')
 elist = file2undef[filename]
 elist.sort()
 for ext in elist:
 if len(ext) >= 8:
 tabs = '\t'
 else:
 tabs = '\t\t'
 if ext not in def2file:
 print('\t' + ext + tabs + ' *undefined')
 else:
 print('\t' + ext + tabs + flat(def2file[ext]))

# Print for each module the names of the other modules that use it.
#
def printcaller():
 files = sorted(file2def.keys())
 for filename in files:
 callers = []
 for label in file2def[filename]:
 if label in undef2file:
 callers = callers + undef2file[label]
 if callers:
 callers.sort()
 print(filename + ':')
 lastfn = ''
 for fn in callers:
 if fn != lastfn:
 print('\t' + fn)
 lastfn = fn
 else:
 print(filename + ': unused')

# Print undefined names and where they are used.
#
def printundef():
 undefs = {}
 for filename in list(file2undef.keys()):
 for ext in file2undef[filename]:
 if ext not in def2file:
 store(undefs, ext, filename)
 elist = sorted(undefs.keys())
 for ext in elist:
 print(ext + ':')
 flist = sorted(undefs[ext])
 for filename in flist:
 print('\t' + filename)

# Print warning messages about names defined in more than one file.
#
def warndups():
 savestdout = sys.stdout
 sys.stdout = sys.stderr
 names = sorted(def2file.keys())
 for name in names:
 if len(def2file[name]) > 1:
 print('warning:', name, 'multiply defined:', end=' ')
 print(flat(def2file[name]))
 sys.stdout = savestdout

# Main program
#
def main():
 try:
 optlist, args = getopt.getopt(sys.argv[1:], 'cdu')
 except getopt.error:
 sys.stdout = sys.stderr
 print('Usage:', os.path.basename(sys.argv[0]), end=' ')
 print('[-cdu] [file] ...')
 print('-c: print callers per objectfile')
 print('-d: print callees per objectfile')
 print('-u: print usage of undefined symbols')
 print('If none of -cdu is specified, all are assumed.')
 print('Use "nm -o" to generate the input')
 print('e.g.: nm -o /lib/libc.a | objgraph')
 return 1
 optu = optc = optd = 0
 for opt, void in optlist:
 if opt == '-u':
 optu = 1
 elif opt == '-c':
 optc = 1
 elif opt == '-d':
 optd = 1
 if optu == optc == optd == 0:
 optu = optc = optd = 1
 if not args:
 args = ['-']
 for filename in args:
 if filename == '-':
 readinput(sys.stdin)
 else:
 with open(filename) as f:
 readinput(f)
 #
 warndups()
 #
 more = (optu + optc + optd > 1)
 if optd:
 if more:
 print('---------------All callees------------------')
 printcallee()
 if optu:
 if more:
 print('---------------Undefined callees------------')
 printundef()
 if optc:
 if more:
 print('---------------All Callers------------------')
 printcaller()
 return 0

# Call the main program.
# Use its return value as exit status.
# Catch interrupts to avoid stack trace.
#
if __name__ == '__main__':
 try:
 sys.exit(main())
 except KeyboardInterrupt:
 sys.exit(1)