xform_inter.py

   1 # ScratchABlock - Program analysis and decompilation framework
   2 #
   3 # Copyright (c) 2015-2018 Paul Sokolovsky
   4 #
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
  17
  18 """Interprocedural transformation passes"""
  19
  20 from graph import Graph
  21 from core import is_addr
  22 import progdb
  23 from utils import maybesorted
  24 import utils
  25
  26
  27 def build_callgraph():
  28     "Build program callgraph from progdb."
  29
  30     callgraph = Graph()
  31
  32     for addr, props in progdb.FUNC_DB_BY_ADDR.items():
  33         callgraph.add_node(props["label"])
  34
  35     for addr, props in progdb.FUNC_DB_BY_ADDR.items():
  36         for callee in props.get("calls", []):
  37             if callee in callgraph:
  38                 callgraph.add_edge(props["label"], callee)
  39
  40     callgraph.number_postorder_forest()
  41
  42     return callgraph
  43
  44
  45 def calc_callsites_live_out(cg, callee):
  46     """Calculate function's callsites_live_out property.
  47
  48     Go thru function's callers (using callgraph), and union their
  49     calls_live_out information pertinent to this function.
  50     """
  51
  52     callers = maybesorted(cg.pred(callee))
  53     # If there're no callers, will return empty set, which
  54     # is formally correct - if there're no callers, the
  55     # function is dead. However, realistically that means
  56     # that callers aren't known, and we should treat that
  57     # specially.
  58     call_lo_union = set()
  59     for c in callers:
  60         clo = progdb.FUNC_DB[c].get("calls_live_out", [])
  61         #print("  %s: calls_live_out: %s" % (c, utils.repr_stable(clo)))
  62         for bbaddr, callee_expr, live_out in clo:
  63             if is_addr(callee_expr) and callee_expr.addr == callee:
  64                 print("  %s: calls_live_out[%s]: %s" % (c, callee, utils.repr_stable((bbaddr, callee_expr, live_out))))
  65                 call_lo_union.update(live_out)
  66
  67     progdb.FUNC_DB[callee]["callsites_live_out"] = call_lo_union
  68
  69     return call_lo_union
  70
  71
  72 def collect_returns():
  73     import progdb
  74     import arch
  75     for addr, props in progdb.FUNC_DB.items():
  76         if "modifieds" in props and "callsites_live_out" in props:
  77             props["returns"] = arch.ret_filter(set(props["modifieds"]) & set(props["callsites_live_out"]))