예제 #1
0
파일: access.py 프로젝트: mmmulani/cs444
def set_simple_var(decl, src):
  '''Given a variable declaration (ASTParam or ASTVariableDeclaration), stores
  the value of src in it.'''
  store_code = []
  if isinstance(decl, ast_param.ASTParam):
    # Method parameter.
    index = CodeGenManager.cur_method.c_get_param_index(decl)
    store_code = common.set_param(index, src, CodeGenManager.N_PARAMS)
  elif decl.c_parent_method is not None:
    # Local variable.
    store_code = common.save_local_var(decl, src)
  else:
    # Last remaining case is a instance field access on the enclosing type.
    if not isinstance(decl, ast_variable_declaration.ASTVariableDeclaration):
      raise Exception('Simple variable is not an instance field')

    scratch_reg = [reg for reg in ['eax', 'ebx'] if reg != src][0]

    store_code = [
      '; using {0} as scratch'.format(scratch_reg),
      'push {0} ; saving scratch'.format(scratch_reg),
      common.get_param(scratch_reg, 0, CodeGenManager.N_PARAMS),
      common.save_instance_field(scratch_reg, decl, src),
      'pop {0} ; restoring scratch'.format(scratch_reg)
    ]

  return store_code
예제 #2
0
파일: access.py 프로젝트: mmmulani/cs444
def get_simple_var(decl):
  '''Given a declaration, return code to get the variable'''
  if isinstance(decl, ast_param.ASTParam):
    # Method param.
    index = CodeGenManager.cur_method.c_get_param_index(decl)
    return common.get_param('eax', index, CodeGenManager.N_PARAMS)
  elif decl.c_parent_method is not None:
    # Local variable.
    return common.get_local_var('eax', decl)

  # Only remaining case should be an (instance) field of the encl type.
  if not isinstance(decl, ast_variable_declaration.ASTVariableDeclaration):
    raise Exception('Invalid instance var value retrieval.')

  # "this" is always the first param from an implicit "this".
  return [
    '; Field access of implicit "this"',
    common.get_param('eax', 0, CodeGenManager.N_PARAMS),
    common.get_instance_field('eax', 'eax', decl)
  ]