1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.dx.ssa.back;
18
19import com.android.dx.ssa.BasicRegisterMapper;
20import com.android.dx.ssa.RegisterMapper;
21import com.android.dx.ssa.SsaMethod;
22
23/**
24 * A register allocator that maps SSA register n to Rop register 2*n,
25 * essentially preserving the original mapping and remaining agnostic
26 * about normal or wide categories. Used for debugging.
27 */
28public class NullRegisterAllocator extends RegisterAllocator {
29    /** {@inheritDoc} */
30    public NullRegisterAllocator(SsaMethod ssaMeth,
31            InterferenceGraph interference) {
32        super(ssaMeth, interference);
33    }
34
35    /** {@inheritDoc} */
36    @Override
37    public boolean wantsParamsMovedHigh() {
38        // We're not smart enough for this.
39        return false;
40    }
41
42    /** {@inheritDoc} */
43    @Override
44    public RegisterMapper allocateRegisters() {
45        int oldRegCount = ssaMeth.getRegCount();
46
47        BasicRegisterMapper mapper = new BasicRegisterMapper(oldRegCount);
48
49        for (int i = 0; i < oldRegCount; i++) {
50            mapper.addMapping(i, i*2, 2);
51        }
52
53        return mapper;
54    }
55}
56