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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 | scripts/checkstack.py
import sys
import re
# Functions that change stacks
STACKHOP = ['stack_hop', 'stack_hop_back']
# List of functions we can assume are never called.
#IGNORE = ['panic', '__dprintf']
IGNORE = ['panic']
OUTPUTDESC = """
#funcname1[preamble_stack_usage,max_usage_with_callers]:
# insn_addr:called_function [usage_at_call_point+caller_preamble,total_usage]
#
#funcname2[p,m,max_usage_to_yield_point]:
# insn_addr:called_function [u+c,t,usage_to_yield_point]
"""
# Find out maximum stack usage for a function
def calcmaxstack(funcs, funcaddr):
info = funcs[funcaddr]
# Find max of all nested calls.
maxusage = info[1]
maxyieldusage = doesyield = 0
if info[3] is not None:
maxyieldusage = info[3]
doesyield = 1
info[2] = maxusage
info[4] = info[3]
seenbefore = {}
totcalls = 0
for insnaddr, calladdr, usage in info[6]:
callinfo = funcs.get(calladdr)
if callinfo is None:
continue
if callinfo[2] is None:
calcmaxstack(funcs, calladdr)
if callinfo[0] not in seenbefore:
seenbefore[callinfo[0]] = 1
totcalls += 1 + callinfo[5]
funcnameroot = callinfo[0].split('.')[0]
if funcnameroot in IGNORE:
# This called function is ignored - don't contribute it to
# the max stack.
continue
if funcnameroot in STACKHOP:
if usage > maxusage:
maxusage = usage
if callinfo[4] is not None:
doesyield = 1
if usage > maxyieldusage:
maxyieldusage = usage
continue
totusage = usage + callinfo[2]
if totusage > maxusage:
maxusage = totusage
if callinfo[4] is not None:
doesyield = 1
totyieldusage = usage + callinfo[4]
if totyieldusage > maxyieldusage:
maxyieldusage = totyieldusage
info[2] = maxusage
if doesyield:
info[4] = maxyieldusage
info[5] = totcalls
# Try to arrange output so that functions that call each other are
# near each other.
def orderfuncs(funcaddrs, availfuncs):
l = [(availfuncs[funcaddr][5], availfuncs[funcaddr][0], funcaddr)
for funcaddr in funcaddrs if funcaddr in availfuncs]
l.sort()
l.reverse()
out = []
while l:
count, name, funcaddr = l.pop(0)
if funcaddr not in availfuncs:
continue
calladdrs = [calls[1] for calls in availfuncs[funcaddr][6]]
del availfuncs[funcaddr]
out = out + orderfuncs(calladdrs, availfuncs) + [funcaddr]
return out
# Update function info with a found "yield" point.
def noteYield(info, stackusage):
prevyield = info[3]
if prevyield is None or prevyield < stackusage:
info[3] = stackusage
# Update function info with a found "call" point.
def noteCall(info, subfuncs, insnaddr, calladdr, stackusage):
if (calladdr, stackusage) in subfuncs:
# Already noted a nearly identical call - ignore this one.
return
info[6].append((insnaddr, calladdr, stackusage))
subfuncs[(calladdr, stackusage)] = 1
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[f]?[lw])|(sub.* [$](?P<num>0x' + hex_s + r'),%esp)$')
def calc():
# funcs[funcaddr] = [funcname, basicstackusage, maxstackusage
# , yieldusage, maxyieldusage, totalcalls
# , [(insnaddr, calladdr, stackusage), ...]]
funcs = {-1: ['<indirect>', 0, 0, None, None, 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, None, None, 0, []]
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.startswith('pushl') or insn.startswith('pushfl'):
stackusage += 4
continue
elif insn.startswith('pushw') or insn.startswith('pushfw'):
stackusage += 2
continue
stackusage += int(im.group('num'), 16)
if atstart:
if '%esp' in insn or insn.startswith('leal'):
# Still part of initial header
continue
cur[1] = stackusage
atstart = 0
insnaddr = m.group('insnaddr')
calladdr = m.group('calladdr')
if calladdr is None:
if insn.startswith('lcallw'):
noteCall(cur, subfuncs, insnaddr, -1, stackusage + 4)
noteYield(cur, stackusage + 4)
elif insn.startswith('int'):
noteCall(cur, subfuncs, insnaddr, -1, stackusage + 6)
noteYield(cur, stackusage + 6)
elif insn.startswith('sti'):
noteYield(cur, stackusage)
else:
# misc instruction
continue
else:
# Jump or call insn
calladdr = int(calladdr, 16)
ref = m.group('ref')
if '+' in ref:
# Inter-function jump.
pass
elif insn.startswith('j'):
# Tail call
noteCall(cur, subfuncs, insnaddr, calladdr, 0)
elif insn.startswith('calll'):
noteCall(cur, subfuncs, insnaddr, calladdr, stackusage + 4)
elif insn.startswith('callw'):
noteCall(cur, subfuncs, insnaddr, calladdr, stackusage + 2)
else:
print("unknown call", ref)
noteCall(cur, subfuncs, insnaddr, calladdr, stackusage)
# Reset stack usage to preamble usage
stackusage = cur[1]
#print("other", repr(line))
# Calculate maxstackusage
for funcaddr, info in funcs.items():
if info[2] is not None:
continue
calcmaxstack(funcs, funcaddr)
# Sort functions for output
funcaddrs = orderfuncs(funcs.keys(), funcs.copy())
# Show all functions
print(OUTPUTDESC)
for funcaddr in funcaddrs:
name, basicusage, maxusage, yieldusage, maxyieldusage, count, calls = \
funcs[funcaddr]
if maxusage == 0 and maxyieldusage is None:
continue
yieldstr = ""
if maxyieldusage is not None:
yieldstr = ",%d" % maxyieldusage
print("\n%s[%d,%d%s]:" % (name, basicusage, maxusage, yieldstr))
for insnaddr, calladdr, stackusage in calls:
callinfo = funcs.get(calladdr, ("<unknown>", 0, 0, 0, None))
yieldstr = ""
if callinfo[4] is not None:
yieldstr = ",%d" % (stackusage + callinfo[4])
print(" %04s:%-40s [%d+%d,%d%s]" % (
insnaddr, callinfo[0], stackusage, callinfo[1]
, stackusage+callinfo[2], yieldstr))
def main():
calc()
if __name__ == '__main__':
main()
|
