#!/usr/bin/env python3

"""
This script is used to detect functions in the source code which are no longer
used. It should be used after compiling all the different executables with the
following flags:

CXXFLAGS += "-ffunction-sections"
LDFLAGS += "-Wl,-gc-sections"

It will then use nm to get all "T" symbols from all .o files generated by
compilation, and compare those symbols to the symbols in the executables.
Symbols not in any executable likely are unused.
"""

import os, glob

def nm(filename):
    return os.popen("nm -C %s" % filename).read()

output1 = []
for o in glob.glob("build/release/*.o") + glob.glob("build/release/*/*.o") + \
         glob.glob("build/release/*/*/*.o") + glob.glob("build/release/*/*/*/*.o"):
    output1.append((o, nm(o)))

output2 = nm("wesnoth")
output2 += nm("campaignd")
output2 += nm("wesnothd")

def extract(line):
    return line[line.find(" T ") + 3:]

def symbols(lines):
    return [extract(x) for x in lines.splitlines() if " T " in x]

symbols2 = symbols(output2)

for o in output1:
    symbols1 = symbols(o[1])

    found = []
    for symbol in symbols1:
        if not symbol in symbols2:
            found += [symbol]

    if found:
        print("%s:" % o[0])
        print("\n".join(found))
        print()