1 /* 2 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package vm.compiler.coverage.parentheses.share; 24 25 import java.util.List; 26 27 /** 28 * Tiny stack InstructionsExecutor. This executor verifies HotspotInstructionsExecutor 29 */ 30 public class TinyInstructionsExecutor implements InstructionsExecutor { 31 32 private int[] stack; 33 private int stackHead = -1; 34 35 public TinyInstructionsExecutor(int stackSize) { 36 stack = new int[stackSize]; 37 } 38 39 private void putOnStack(int v) { 40 stack[++stackHead] = v; 41 } 42 43 private void exec(Instruction instruction) { 44 switch (instruction) { 45 case ICONST_M1: 46 putOnStack(-1); 47 break; 48 case ICONST_0: 49 putOnStack(0); 50 break; 51 case ICONST_1: 52 putOnStack(1); 53 break; 54 case ICONST_2: 55 putOnStack(2); 56 break; 57 case ICONST_3: 58 putOnStack(3); 59 break; 60 case ICONST_4: 61 putOnStack(4); 62 break; 63 case ICONST_5: 64 putOnStack(5); 65 break; 66 case DUP: 67 stack[stackHead + 1] = stack[stackHead]; 68 stackHead++; 69 break; 70 71 case IADD: 72 stack[stackHead - 1] += stack[stackHead]; 73 stackHead--; 74 break; 75 case ISUB: 76 stack[stackHead - 1] -= stack[stackHead]; 77 stackHead--; 78 break; 79 case IMUL: 80 stack[stackHead - 1] *= stack[stackHead]; 81 stackHead--; 82 break; 83 case IOR: 84 stack[stackHead - 1] |= stack[stackHead]; 85 stackHead--; 86 break; 87 case IAND: 88 stack[stackHead - 1] &= stack[stackHead]; 89 stackHead--; 90 break; 91 case IXOR: 92 stack[stackHead - 1] ^= stack[stackHead]; 93 stackHead--; 94 break; 95 case ISHL: 96 stack[stackHead - 1] <<= stack[stackHead]; 97 stackHead--; 98 break; 99 case ISHR: 100 stack[stackHead - 1] >>= stack[stackHead]; 101 stackHead--; 102 break; 103 104 case SWAP: { 105 int t = stack[stackHead]; 106 stack[stackHead] = stack[stackHead - 1]; 107 stack[stackHead - 1] = t; 108 break; 109 } 110 case NOP: 111 break; 112 case INEG: 113 stack[stackHead] = -stack[stackHead]; 114 break; 115 } 116 } 117 118 private int top() { 119 return stack[stackHead]; 120 } 121 122 @Override 123 public int execute(List<Instruction> instructions) { 124 for (Instruction instruction : instructions) { 125 exec(instruction); 126 } 127 return top(); 128 } 129 }