src/analysis/remove_out_of_init_get_test.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2009 Jean-Sebastien Gelinas <calestar@gmail.com>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #        http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # This package introduces an optimization that removes 'get' tests when
  18 # not reachable from an initializer
  19 package remove_out_of_init_get_test
  20
  21 import reachable_from_init_method_analysis
  22
  23 redef class Program
  24         # Calling this method will remove all 'isset' that were generated automaticaly
  25         # before a attribute read if this attribute read is done in a method that
  26         # cannot be reached by a initializer
  27         fun optimize_out_of_init_getters do
  28                 with_each_iroutines !action(i,m) do
  29                         if not rfima.is_iroutine_reachable_from_init(i) then
  30                                 var remover = new GetterTestRemover
  31                                 remover.visit_iroutine(i)
  32                         end
  33                 end
  34         end
  35 end
  36
  37 class GetterTestRemover
  38 special ICodeVisitor
  39         redef fun visit_icode(ic)
  40         do
  41                 # Replace 'x = isset(y)' by 'x = true'
  42                 if ic isa IAttrIsset then
  43                         var result = ic.result
  44                         assert result != null
  45                         var e =  new INative("TAG_Bool(true)", null)
  46                         e.is_pure = true
  47                         e.result = result
  48                         current_icode.insert_before(e)
  49                         current_icode.delete
  50                 end
  51
  52                 super
  53         end
  54 end