001    /*
002     * Copyright 2010-2013 JetBrains s.r.o.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     * http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    
017    package org.jetbrains.jet.lang.cfg;
018    
019    import kotlin.Function1;
020    import org.jetbrains.annotations.NotNull;
021    import org.jetbrains.jet.lang.cfg.pseudocode.*;
022    import org.jetbrains.jet.lang.psi.JetElement;
023    
024    public class TailRecursionDetector extends InstructionVisitorWithResult<Boolean> implements Function1<Instruction, Boolean> {
025        private final JetElement subroutine;
026        private final Instruction start;
027    
028        public TailRecursionDetector(@NotNull JetElement subroutine, @NotNull Instruction start) {
029            this.subroutine = subroutine;
030            this.start = start;
031        }
032    
033        @Override
034        public Boolean invoke(@NotNull Instruction instruction) {
035            return instruction == start || instruction.accept(this);
036        }
037    
038        @Override
039        public Boolean visitInstruction(Instruction instruction) {
040            return false;
041        }
042    
043        @Override
044        public Boolean visitSubroutineExit(SubroutineExitInstruction instruction) {
045            return !instruction.isError() && instruction.getSubroutine() == subroutine;
046        }
047    
048        @Override
049        public Boolean visitSubroutineSink(SubroutineSinkInstruction instruction) {
050            return instruction.getSubroutine() == subroutine;
051        }
052    
053        @Override
054        public Boolean visitJump(AbstractJumpInstruction instruction) {
055            return true;
056        }
057    
058        @Override
059        public Boolean visitThrowExceptionInstruction(ThrowExceptionInstruction instruction) {
060            return false;
061        }
062    
063        @Override
064        public Boolean visitMarkInstruction(MarkInstruction instruction) {
065            return true;
066        }
067    }