cfgutils.py

   1 from core import BBlock, CFGPrinter
   2
   3
   4 def dump(cfg):
   5     CFGPrinter(cfg).print()
   6
   7
   8 def save_cfg(cfg, suffix):
   9     with open(cfg.filename + suffix, "w") as out:
  10         p = CFGPrinter(cfg, out)
  11         p.print()
  12
  13
  14 def swap_if_branches(cfg, node):
  15     "Assuming `node` is 'if' node, swap its branches and invert condition."
  16     succ = cfg.sorted_succ(node)
  17     print(succ, cfg[node, succ[0]])
  18     cond = cfg[node, succ[0]]["cond"]
  19     cfg[node, succ[0]]["cond"] = None
  20     cfg[node, succ[1]]["cond"] = cond.neg()
  21
  22
  23 def detach_node(cfg, n):
  24     din = cfg.degree_in(n)
  25     dout = cfg.degree_out(n)
  26     assert din == 1 or dout == 1
  27     if din == 1:
  28         pred = cfg.pred(n)[0]
  29         cfg.move_succ(n, pred)
  30     else:
  31         succ = cfg.succ(n)[0]
  32         cfg.move_pred(n, succ)
  33     cfg.remove_node(n)
  34
  35
  36 def foreach_node(cfg, func):
  37     """Call function for each node of graph, passing node's properties.
  38     """
  39     for addr, info in cfg.iter_sorted_nodes():
  40         func(info)
  41
  42
  43 def foreach_bblock(cfg, func, join_func=lambda a, b: a or b, **kwargs):
  44     """Apply basic-block level transformation to each block in CFG.
  45     Return cumulative status (OR of each block's status).
  46     """
  47     res = Ellipsis
  48     for addr, info in cfg.iter_sorted_nodes():
  49         bblock = info["val"]
  50         r = func(bblock, **kwargs)
  51         if res is Ellipsis:
  52             res = r
  53         else:
  54             res = join_func(res, r)
  55     return res
  56
  57
  58 def foreach_bblock_and_subblock(cfg, func):
  59     def apply(bblock, func):
  60         if type(bblock) is BBlock:
  61             func(bblock)
  62         else:
  63             for sub in bblock.subblocks():
  64                 apply(sub, func)
  65
  66     for addr, info in cfg.iter_sorted_nodes():
  67         bblock = info["val"]
  68         apply(bblock, func)
  69
  70
  71 def foreach_inst(cfg, func, **kwargs):
  72     def inst_handler(bblock):
  73         for inst in bblock.items:
  74             func(inst, **kwargs)
  75     foreach_bblock_and_subblock(cfg, inst_handler)
  76
  77
  78 def copy_bblocks_props(cfg_from, cfg_to):
  79     def copy(bblock):
  80         cfg_to[bblock.addr]["val"].props = bblock.props.copy()
  81
  82     foreach_bblock(cfg_from, copy)