1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/vm/src/main/java/org/apidesign/vm4brwsr/StackMapper.java Wed Dec 12 11:04:02 2012 +0100
1.3 @@ -0,0 +1,194 @@
1.4 +/**
1.5 + * Back 2 Browser Bytecode Translator
1.6 + * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
1.7 + *
1.8 + * This program is free software: you can redistribute it and/or modify
1.9 + * it under the terms of the GNU General Public License as published by
1.10 + * the Free Software Foundation, version 2 of the License.
1.11 + *
1.12 + * This program is distributed in the hope that it will be useful,
1.13 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.14 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.15 + * GNU General Public License for more details.
1.16 + *
1.17 + * You should have received a copy of the GNU General Public License
1.18 + * along with this program. Look for COPYING file in the top folder.
1.19 + * If not, see http://opensource.org/licenses/GPL-2.0.
1.20 + */
1.21 +package org.apidesign.vm4brwsr;
1.22 +
1.23 +import org.apidesign.javap.TypeArray;
1.24 +
1.25 +public final class StackMapper {
1.26 + private final TypeArray stackTypeIndexPairs;
1.27 + private int[] typeCounters;
1.28 + private int[] typeMaxCounters;
1.29 +
1.30 + public StackMapper() {
1.31 + stackTypeIndexPairs = new TypeArray();
1.32 + typeCounters = new int[VarType.LAST + 1];
1.33 + typeMaxCounters = new int[VarType.LAST + 1];
1.34 + }
1.35 +
1.36 + public void clear() {
1.37 + for (int type = 0; type <= VarType.LAST; ++type) {
1.38 + typeCounters[type] = 0;
1.39 + }
1.40 + stackTypeIndexPairs.clear();
1.41 + }
1.42 +
1.43 + public void syncWithFrameStack(final TypeArray frameStack) {
1.44 + clear();
1.45 +
1.46 + final int size = frameStack.getSize();
1.47 + for (int i = 0; i < size; ++i) {
1.48 + pushTypeImpl(VarType.fromStackMapType(frameStack.get(i)));
1.49 + }
1.50 + }
1.51 +
1.52 + public Variable pushI() {
1.53 + return pushT(VarType.INTEGER);
1.54 + }
1.55 +
1.56 + public Variable pushL() {
1.57 + return pushT(VarType.LONG);
1.58 + }
1.59 +
1.60 + public Variable pushF() {
1.61 + return pushT(VarType.FLOAT);
1.62 + }
1.63 +
1.64 + public Variable pushD() {
1.65 + return pushT(VarType.DOUBLE);
1.66 + }
1.67 +
1.68 + public Variable pushA() {
1.69 + return pushT(VarType.REFERENCE);
1.70 + }
1.71 +
1.72 + public Variable pushT(final int type) {
1.73 + return getVariable(pushTypeImpl(type));
1.74 + }
1.75 +
1.76 + public Variable popI() {
1.77 + return popT(VarType.INTEGER);
1.78 + }
1.79 +
1.80 + public Variable popL() {
1.81 + return popT(VarType.LONG);
1.82 + }
1.83 +
1.84 + public Variable popF() {
1.85 + return popT(VarType.FLOAT);
1.86 + }
1.87 +
1.88 + public Variable popD() {
1.89 + return popT(VarType.DOUBLE);
1.90 + }
1.91 +
1.92 + public Variable popA() {
1.93 + return popT(VarType.REFERENCE);
1.94 + }
1.95 +
1.96 + public Variable popT(final int type) {
1.97 + final Variable variable = getT(0, type);
1.98 + popImpl(1);
1.99 + return variable;
1.100 + }
1.101 +
1.102 + public Variable pop() {
1.103 + final Variable variable = get(0);
1.104 + popImpl(1);
1.105 + return variable;
1.106 + }
1.107 +
1.108 + public void pop(final int count) {
1.109 + final int stackSize = stackTypeIndexPairs.getSize();
1.110 + if (count > stackSize) {
1.111 + throw new IllegalStateException("Stack underflow");
1.112 + }
1.113 + popImpl(count);
1.114 + }
1.115 +
1.116 + public Variable getI(final int indexFromTop) {
1.117 + return getT(indexFromTop, VarType.INTEGER);
1.118 + }
1.119 +
1.120 + public Variable getL(final int indexFromTop) {
1.121 + return getT(indexFromTop, VarType.LONG);
1.122 + }
1.123 +
1.124 + public Variable getF(final int indexFromTop) {
1.125 + return getT(indexFromTop, VarType.FLOAT);
1.126 + }
1.127 +
1.128 + public Variable getD(final int indexFromTop) {
1.129 + return getT(indexFromTop, VarType.DOUBLE);
1.130 + }
1.131 +
1.132 + public Variable getA(final int indexFromTop) {
1.133 + return getT(indexFromTop, VarType.REFERENCE);
1.134 + }
1.135 +
1.136 + public Variable getT(final int indexFromTop, final int type) {
1.137 + final int stackSize = stackTypeIndexPairs.getSize();
1.138 + if (indexFromTop >= stackSize) {
1.139 + throw new IllegalStateException("Stack underflow");
1.140 + }
1.141 + final int stackValue =
1.142 + stackTypeIndexPairs.get(stackSize - indexFromTop - 1);
1.143 + if ((stackValue & 0xff) != type) {
1.144 + throw new IllegalStateException("Type mismatch");
1.145 + }
1.146 +
1.147 + return getVariable(stackValue);
1.148 + }
1.149 +
1.150 + public Variable get(final int indexFromTop) {
1.151 + final int stackSize = stackTypeIndexPairs.getSize();
1.152 + if (indexFromTop >= stackSize) {
1.153 + throw new IllegalStateException("Stack underflow");
1.154 + }
1.155 + final int stackValue =
1.156 + stackTypeIndexPairs.get(stackSize - indexFromTop - 1);
1.157 +
1.158 + return getVariable(stackValue);
1.159 + }
1.160 +
1.161 + private int pushTypeImpl(final int type) {
1.162 + final int count = typeCounters[type];
1.163 + final int value = (count << 8) | (type & 0xff);
1.164 + incCounter(type);
1.165 + stackTypeIndexPairs.add(value);
1.166 +
1.167 + return value;
1.168 + }
1.169 +
1.170 + private void popImpl(final int count) {
1.171 + final int stackSize = stackTypeIndexPairs.getSize();
1.172 + for (int i = stackSize - count; i < stackSize; ++i) {
1.173 + final int value = stackTypeIndexPairs.get(i);
1.174 + decCounter(value & 0xff);
1.175 + }
1.176 +
1.177 + stackTypeIndexPairs.setSize(stackSize - count);
1.178 + }
1.179 +
1.180 + private void incCounter(final int type) {
1.181 + final int newValue = ++typeCounters[type];
1.182 + if (typeMaxCounters[type] < newValue) {
1.183 + typeMaxCounters[type] = newValue;
1.184 + }
1.185 + }
1.186 +
1.187 + private void decCounter(final int type) {
1.188 + --typeCounters[type];
1.189 + }
1.190 +
1.191 + public Variable getVariable(final int typeAndIndex) {
1.192 + final int type = typeAndIndex & 0xff;
1.193 + final int index = typeAndIndex >> 8;
1.194 +
1.195 + return Variable.getStackVariable(type, index);
1.196 + }
1.197 +}