code.kerkeslager.com Git - fur/blob - optimization.py

   1 from crossplatform_ir_generation import CIRProgram, CIRInstruction, CIRLabel
   2
   3 PUSHING_INSTRUCTIONS_WITHOUT_SIDE_EFFECTS = set(
   4     ('push',),
   5 )
   6
   7 def push_drop_optimization(ir):
   8     ir = tuple(ir)
   9
  10     i = 0
  11
  12     while i < len(ir):
  13         if isinstance(ir[i], CIRInstruction)\
  14                 and ir[i].instruction in PUSHING_INSTRUCTIONS_WITHOUT_SIDE_EFFECTS\
  15                 and i + 1 < len(ir)\
  16                 and isinstance(ir[i + 1], CIRInstruction)\
  17                 and ir[i + 1].instruction == 'drop':
  18             i += 2
  19         else:
  20             yield ir[i]
  21             i += 1
  22
  23 # TODO This can be smarter
  24 def unused_pop_optimization(ir):
  25     ir = tuple(ir)
  26
  27     used_symbols = set()
  28
  29     for entry in ir:
  30         # TODO Having symbols be a string starting with "sym" is a bit hacky
  31         if isinstance(entry, CIRInstruction)\
  32                 and entry.instruction != 'pop'\
  33                 and isinstance(entry.argument, str)\
  34                 and entry.argument.startswith('sym'):
  35             used_symbols.add(entry.argument)
  36
  37     for entry in ir:
  38         if isinstance(entry, CIRInstruction) and entry.instruction == 'pop' and entry.argument not in used_symbols:
  39             yield CIRInstruction(instruction='drop', argument=None)
  40         else:
  41             yield entry
  42
  43 def optimize(cir_program):
  44     ir = cir_program.entry_list
  45
  46     ir = push_drop_optimization(ir)
  47     ir = unused_pop_optimization(ir)
  48
  49     return CIRProgram(entry_list=tuple(ir))