| /* |
| * Copyright (C) 2008 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.dx.ssa; |
| |
| import com.android.dx.rop.code.CstInsn; |
| import com.android.dx.rop.code.LocalItem; |
| import com.android.dx.rop.code.RegOps; |
| import com.android.dx.rop.code.RegisterSpec; |
| import com.android.dx.rop.cst.CstInteger; |
| import java.util.HashSet; |
| import java.util.List; |
| |
| /** |
| * Combine identical move-param insns, which may result from Ropper's |
| * handling of synchronized methods. |
| */ |
| public class MoveParamCombiner { |
| |
| /** method to process */ |
| private final SsaMethod ssaMeth; |
| |
| /** |
| * Processes a method with this optimization step. |
| * |
| * @param ssaMethod method to process |
| */ |
| public static void process(SsaMethod ssaMethod) { |
| new MoveParamCombiner(ssaMethod).run(); |
| } |
| |
| private MoveParamCombiner(SsaMethod ssaMeth) { |
| this.ssaMeth = ssaMeth; |
| } |
| |
| /** |
| * Runs this optimization step. |
| */ |
| private void run() { |
| // This will contain the definition specs for each parameter |
| final RegisterSpec[] paramSpecs |
| = new RegisterSpec[ssaMeth.getParamWidth()]; |
| |
| // Insns to delete when all done |
| final HashSet<SsaInsn> deletedInsns = new HashSet(); |
| |
| ssaMeth.forEachInsn(new SsaInsn.Visitor() { |
| public void visitMoveInsn (NormalSsaInsn insn) { |
| } |
| public void visitPhiInsn (PhiInsn phi) { |
| } |
| public void visitNonMoveInsn (NormalSsaInsn insn) { |
| if (insn.getOpcode().getOpcode() != RegOps.MOVE_PARAM) { |
| return; |
| } |
| |
| int param = getParamIndex(insn); |
| |
| if (paramSpecs[param] == null) { |
| paramSpecs[param] = insn.getResult(); |
| } else { |
| final RegisterSpec specA = paramSpecs[param]; |
| final RegisterSpec specB = insn.getResult(); |
| LocalItem localA = specA.getLocalItem(); |
| LocalItem localB = specB.getLocalItem(); |
| LocalItem newLocal; |
| |
| /* |
| * Is there local information to preserve? |
| */ |
| |
| if (localA == null) { |
| newLocal = localB; |
| } else if (localB == null) { |
| newLocal = localA; |
| } else if (localA.equals(localB)) { |
| newLocal = localA; |
| } else { |
| /* |
| * Oddly, these two identical move-params have distinct |
| * debug info. We'll just keep them distinct. |
| */ |
| return; |
| } |
| |
| ssaMeth.getDefinitionForRegister(specA.getReg()) |
| .setResultLocal(newLocal); |
| |
| /* |
| * Map all uses of specB to specA |
| */ |
| |
| RegisterMapper mapper = new RegisterMapper() { |
| /** @inheritDoc */ |
| public int getNewRegisterCount() { |
| return ssaMeth.getRegCount(); |
| } |
| |
| /** @inheritDoc */ |
| public RegisterSpec map(RegisterSpec registerSpec) { |
| if (registerSpec.getReg() == specB.getReg()) { |
| return specA; |
| } |
| |
| return registerSpec; |
| } |
| }; |
| |
| List<SsaInsn> uses |
| = ssaMeth.getUseListForRegister(specB.getReg()); |
| |
| // Use list is modified by mapSourceRegisters |
| for (int i = uses.size() - 1; i >= 0; i--) { |
| SsaInsn use = uses.get(i); |
| use.mapSourceRegisters(mapper); |
| } |
| |
| deletedInsns.add(insn); |
| } |
| |
| } |
| }); |
| |
| ssaMeth.deleteInsns(deletedInsns); |
| } |
| |
| /** |
| * Returns the parameter index associated with a move-param insn. Does |
| * not verify that the insn is a move-param insn. |
| * |
| * @param insn {@code non-null;} a move-param insn |
| * @return {@code >=0;} parameter index |
| */ |
| private int getParamIndex(NormalSsaInsn insn) { |
| CstInsn cstInsn = (CstInsn)(insn.getOriginalRopInsn()); |
| |
| int param = ((CstInteger)cstInsn.getConstant()).getValue(); |
| return param; |
| } |
| |
| } |