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#!/usr/bin/env python
# Script that tries to find how much stack space each function in an
# object is using.
#
# Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
#
# This file may be distributed under the terms of the GNU GPLv3 license.
# Usage:
# objdump -m i386 -M i8086 -M suffix -d out/rom16.o | tools/checkstack.py
import sys
import re
# List of functions we can assume are never called.
#IGNORE = ['panic', '__dprintf', '__send_disk_op']
IGNORE = ['panic', '__send_disk_op']
# Find out maximum stack usage for a function
def calcmaxstack(funcs, funcaddr):
info = funcs[funcaddr]
# Find max of all nested calls.
max = info[1]
info[2] = max
for insnaddr, calladdr, usage in info[3]:
callinfo = funcs[calladdr]
if callinfo[2] is None:
calcmaxstack(funcs, calladdr)
if callinfo[0].split('.')[0] in IGNORE:
# This called function is ignored - don't contribute it to
# the max stack.
continue
totusage = usage + callinfo[2]
if totusage > max:
max = totusage
info[2] = max
hex_s = r'[0-9a-f]+'
re_func = re.compile(r'^(?P<funcaddr>' + hex_s + r') <(?P<func>.*)>:$')
re_asm = re.compile(
r'^[ ]*(?P<insnaddr>' + hex_s
+ r'):\t.*\t(addr32 )?(?P<insn>.+?)[ ]*((?P<calladdr>' + hex_s
+ r') <(?P<ref>.*)>)?$')
re_usestack = re.compile(
r'^(push.*)|(sub.* [$](?P<num>0x' + hex_s + r'),%esp)$')
def calc():
# funcs[funcaddr] = [funcname, basicstackusage, maxstackusage
# , [(addr, callfname, stackusage), ...]]
funcs = {-1: ['<indirect>', 0, 0, []]}
cur = None
atstart = 0
stackusage = 0
# Parse input lines
for line in sys.stdin.readlines():
m = re_func.match(line)
if m is not None:
# Found function
funcaddr = int(m.group('funcaddr'), 16)
funcs[funcaddr] = cur = [m.group('func'), 0, None, []]
stackusage = 0
atstart = 1
subfuncs = {}
continue
m = re_asm.match(line)
if m is not None:
insn = m.group('insn')
im = re_usestack.match(insn)
if im is not None:
if insn[:5] == 'pushl' or insn[:6] == 'pushfl':
stackusage += 4
continue
elif insn[:5] == 'pushw' or insn[:6] == 'pushfw':
stackusage += 2
continue
stackusage += int(im.group('num'), 16)
if atstart:
cur[1] = stackusage
atstart = 0
calladdr = m.group('calladdr')
if calladdr is None:
if insn[:6] == 'lcallw':
stackusage += 4
calladdr = -1
else:
# misc instruction - just ignore
continue
else:
# Jump or call insn
calladdr = int(calladdr, 16)
ref = m.group('ref')
if '+' in ref:
# Inter-function jump - reset stack usage to
# preamble usage
stackusage = cur[1]
continue
if insn[:1] == 'j':
# Tail call
stackusage = 0
elif insn[:5] == 'calll':
stackusage += 4
else:
print "unknown call", ref
if (calladdr, stackusage) not in subfuncs:
cur[3].append((m.group('insnaddr'), calladdr, stackusage))
subfuncs[(calladdr, stackusage)] = 1
# Reset stack usage to preamble usage
stackusage = cur[1]
continue
#print "other", repr(line)
# Calculate maxstackusage
bynames = {}
for funcaddr, info in funcs.items():
bynames[info[0]] = info
if info[2] is not None:
continue
calcmaxstack(funcs, funcaddr)
# Show all functions
funcnames = bynames.keys()
funcnames.sort()
for funcname in funcnames:
name, basicusage, maxusage, calls = bynames[funcname]
if maxusage == 0:
continue
print "\n%s[%d,%d]:" % (funcname, basicusage, maxusage)
for insnaddr, calladdr, stackusage in calls:
callinfo = funcs[calladdr]
print " %04s:%-40s [%d+%d,%d]" % (
insnaddr, callinfo[0], stackusage, callinfo[1]
, stackusage+callinfo[2])
def main():
calc()
if __name__ == '__main__':
main()
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