| #!/usr/bin/env python |
| # -*- coding: utf-8 -*- |
| # |
| # Copyright (c) 2018 Free Software Foundation |
| # Contributed by Bernhard Reutner-Fischer <aldot@gcc.gnu.org> |
| # Inspired by bloat-o-meter from busybox. |
| |
| # This software may be used and distributed according to the terms and |
| # conditions of the GNU General Public License as published by the Free |
| # Software Foundation. |
| |
| # For a set of object-files, determine symbols that are |
| # - public but should be static |
| |
| # Examples: |
| # unused_functions.py ./gcc/fortran |
| # unused_functions.py gcc/c gcc/c-family/ gcc/*-c.o | grep -v "'gt_" |
| # unused_functions.py gcc/cp gcc/c-family/ gcc/*-c.o | grep -v "'gt_" |
| |
| import sys, os |
| from tempfile import mkdtemp |
| from subprocess import Popen, PIPE |
| |
| def usage(): |
| sys.stderr.write("usage: %s [-v] [dirs | files] [-- <readelf options>]\n" |
| % sys.argv[0]) |
| sys.stderr.write("\t-v\tVerbose output\n"); |
| sys.exit(1) |
| |
| (odir, sym_args, tmpd, verbose) = (set(), "", None, False) |
| |
| for i in range(1, len(sys.argv)): |
| f = sys.argv[i] |
| if f == '--': # sym_args |
| sym_args = ' '.join(sys.argv[i + 1:]) |
| break |
| if f == '-v': |
| verbose = True |
| continue |
| if not os.path.exists(f): |
| sys.stderr.write("Error: No such file or directory '%s'\n" % f) |
| usage() |
| else: |
| if f.endswith('.a') and tmpd is None: |
| tmpd = mkdtemp(prefix='unused_fun') |
| odir.add(f) |
| |
| def dbg(args): |
| if not verbose: return |
| print(args) |
| |
| def get_symbols(file): |
| syms = {} |
| rargs = "readelf -W -s %s %s" % (sym_args, file) |
| p0 = Popen((a for a in rargs.split(' ') if a.strip() != ''), stdout=PIPE) |
| p1 = Popen(["c++filt"], stdin=p0.stdout, stdout=PIPE, |
| universal_newlines=True) |
| lines = p1.communicate()[0] |
| for l in lines.split('\n'): |
| l = l.strip() |
| if not len(l) or not l[0].isdigit(): continue |
| larr = l.split() |
| if len(larr) != 8: continue |
| num, value, size, typ, bind, vis, ndx, name = larr |
| if typ == 'SECTION' or typ == 'FILE': continue |
| # I don't think we have many aliases in gcc, re-instate the addr |
| # lut otherwise. |
| if vis != 'DEFAULT': continue |
| #value = int(value, 16) |
| #size = int(size, 16) if size.startswith('0x') else int(size) |
| defined = ndx != 'UND' |
| globl = bind == 'GLOBAL' |
| # c++ RID_FUNCTION_NAME dance. FORNOW: Handled as local use |
| # Is that correct? |
| if name.endswith('::__FUNCTION__') and typ == 'OBJECT': |
| name = name[0:(len(name) - len('::__FUNCTION__'))] |
| if defined: defined = False |
| if defined and not globl: continue |
| syms.setdefault(name, {}) |
| syms[name][['use','def'][defined]] = True |
| syms[name][['local','global'][globl]] = True |
| # Note: we could filter out e.g. debug_* symbols by looking for |
| # value in the debug_macro sections. |
| if p1.returncode != 0: |
| print("Warning: Reading file '%s' exited with %r|%r" |
| % (file, p0.returncode, p1.returncode)) |
| p0.kill() |
| return syms |
| |
| (oprog, nprog) = ({}, {}) |
| |
| def walker(paths): |
| def ar_x(archive): |
| dbg("Archive %s" % path) |
| f = os.path.abspath(archive) |
| f = os.path.splitdrive(f)[1] |
| d = tmpd + os.path.sep + f |
| d = os.path.normpath(d) |
| owd = os.getcwd() |
| try: |
| os.makedirs(d) |
| os.chdir(d) |
| p0 = Popen(["ar", "x", "%s" % os.path.join(owd, archive)], |
| stderr=PIPE, universal_newlines=True) |
| p0.communicate() |
| if p0.returncode > 0: d = None # assume thin archive |
| except: |
| dbg("ar x: Error: %s: %s" % (archive, sys.exc_info()[0])) |
| os.chdir(owd) |
| raise |
| os.chdir(owd) |
| if d: dbg("Extracted to %s" % (d)) |
| return (archive, d) |
| |
| def ar_t(archive): |
| dbg("Thin archive, using existing files:") |
| try: |
| p0 = Popen(["ar", "t", "%s" % archive], stdout=PIPE, |
| universal_newlines=True) |
| ret = p0.communicate()[0] |
| return ret.split('\n') |
| except: |
| dbg("ar t: Error: %s: %s" % (archive, sys.exc_info()[0])) |
| raise |
| |
| prog = {} |
| for path in paths: |
| if os.path.isdir(path): |
| for r, dirs, files in os.walk(path): |
| if files: dbg("Files %s" % ", ".join(files)) |
| if dirs: dbg("Dirs %s" % ", ".join(dirs)) |
| prog.update(walker([os.path.join(r, f) for f in files])) |
| prog.update(walker([os.path.join(r, d) for d in dirs])) |
| else: |
| if path.endswith('.a'): |
| if ar_x(path)[1] is not None: continue # extract worked |
| prog.update(walker(ar_t(path))) |
| if not path.endswith('.o'): continue |
| dbg("Reading symbols from %s" % (path)) |
| prog[os.path.normpath(path)] = get_symbols(path) |
| return prog |
| |
| def resolve(prog): |
| x = prog.keys() |
| use = set() |
| # for each unique pair of different files |
| for (f, g) in ((f,g) for f in x for g in x if f != g): |
| refs = set() |
| # for each defined symbol |
| for s in (s for s in prog[f] if prog[f][s].get('def') and s in prog[g]): |
| if prog[g][s].get('use'): |
| refs.add(s) |
| for s in refs: |
| # Prune externally referenced symbols as speed optimization only |
| for i in (i for i in x if s in prog[i]): del prog[i][s] |
| use |= refs |
| return use |
| |
| try: |
| oprog = walker(odir) |
| if tmpd is not None: |
| oprog.update(walker([tmpd])) |
| oused = resolve(oprog) |
| finally: |
| try: |
| p0 = Popen(["rm", "-r", "-f", "%s" % (tmpd)], stderr=PIPE, stdout=PIPE) |
| p0.communicate() |
| if p0.returncode != 0: raise "rm '%s' didn't work out" % (tmpd) |
| except: |
| from shutil import rmtree |
| rmtree(tmpd, ignore_errors=True) |
| |
| for (i,s) in ((i,s) for i in oprog.keys() for s in oprog[i] if oprog[i][s]): |
| if oprog[i][s].get('def') and not oprog[i][s].get('use'): |
| print("%s: Symbol '%s' declared extern but never referenced externally" |
| % (i,s)) |
| |
| |
