content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.taobao.android.dx.rop.code;
  
  /**
   * Interface for "advice" passed from the late stage of translation back
   * to the early stage. This allows for the final target architecture to
   * exert its influence early in the translation process without having
   * the early stage code be explicitly tied to the target.
   */
  public interface TranslationAdvice {
      /**
       * Returns an indication of whether the target can directly represent an
       * instruction with the given opcode operating on the given arguments,
       * where the last source argument is used as a constant. (That is, the
       * last argument must have a type which indicates it is a known constant.)
       * The instruction associated must have exactly two sources.
       *
       * @param opcode {@code non-null;} the opcode
       * @param sourceA {@code non-null;} the first source
       * @param sourceB {@code non-null;} the second source
       * @return {@code true} iff the target can represent the operation
       * using a constant for the last argument
       */
      public boolean hasConstantOperation(Rop opcode,
                                          RegisterSpec sourceA, RegisterSpec sourceB);
  
      /**
       * Returns true if the translation target requires the sources of the
       * specified opcode to be in order and contiguous (eg, for an invoke-range)
       *
       * @param opcode {@code non-null;} opcode
       * @param sources {@code non-null;} source list
       * @return {@code true} iff the target requires the sources to be
       * in order and contiguous.
       */
      public boolean requiresSourcesInOrder(Rop opcode, RegisterSpecList sources);
  
      /**
       * Gets the maximum register width that can be represented optimally.
       * For example, Dex bytecode does not have instruction forms that take
       * register numbers larger than 15 for all instructions so
       * DexTranslationAdvice returns 15 here.
       *
       * @return register count noted above
       */
      public int getMaxOptimalRegisterCount();
  }
  