dx/src/com/android/jack/dx/ssa/back/NullRegisterAllocator.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

/*
 * 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.android.jack.dx.ssa.back;

import com.android.jack.dx.ssa.BasicRegisterMapper;
import com.android.jack.dx.ssa.RegisterMapper;
import com.android.jack.dx.ssa.SsaMethod;

/**
 * A register allocator that maps SSA register n to Rop register 2*n,
 * essentially preserving the original mapping and remaining agnostic
 * about normal or wide categories. Used for debugging.
 */
public class NullRegisterAllocator extends RegisterAllocator {

  public NullRegisterAllocator(SsaMethod ssaMeth, InterferenceGraph interference) {
    super(ssaMeth, interference);
  }

  @Override
  /** {@inheritDoc} */
  public boolean wantsParamsMovedHigh() {
    // We're not smart enough for this.
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public RegisterMapper allocateRegisters() {
    int oldRegCount = ssaMeth.getRegCount();

    BasicRegisterMapper mapper = new BasicRegisterMapper(oldRegCount);

    for (int i = 0; i < oldRegCount; i++) {
      mapper.addMapping(i, i * 2, 2);
    }

    return mapper;
  }
}