hg/bck2brwsr: src/main/java/org/apidesign/java4browser/ByteCodeToJavaScript.java@cb0cfba1b863

     1 /*

     2 Java 4 Browser Bytecode Translator

     3 Copyright (C) 2012-2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

     5 This program is free software: you can redistribute it and/or modify

     6 it under the terms of the GNU General Public License as published by

     7 the Free Software Foundation, version 2 of the License.

     9 This program is distributed in the hope that it will be useful,

    10 but WITHOUT ANY WARRANTY; without even the implied warranty of

    11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12 GNU General Public License for more details.

    14 You should have received a copy of the GNU General Public License

    15 along with this program. Look for COPYING file in the top folder.

    16 If not, see http://opensource.org/licenses/GPL-2.0.

    17 */

    18 package org.apidesign.java4browser;

    20 import java.io.IOException;

    21 import java.io.InputStream;

    22 import java.util.List;

    23 import static org.netbeans.modules.classfile.ByteCodes.*;

    24 import org.netbeans.modules.classfile.CPClassInfo;

    25 import org.netbeans.modules.classfile.CPEntry;

    26 import org.netbeans.modules.classfile.CPFieldInfo;

    27 import org.netbeans.modules.classfile.CPMethodInfo;

    28 import org.netbeans.modules.classfile.ClassFile;

    29 import org.netbeans.modules.classfile.ClassName;

    30 import org.netbeans.modules.classfile.Code;

    31 import org.netbeans.modules.classfile.Method;

    32 import org.netbeans.modules.classfile.Parameter;

    33 import org.netbeans.modules.classfile.Variable;

    35 /** Translator of the code inside class files to JavaScript.

    36  *

    37  * @author Jaroslav Tulach <jtulach@netbeans.org>

    38  */

    39 public final class ByteCodeToJavaScript {

    40     private final ClassFile jc;

    41     private final Appendable out;

    43     private ByteCodeToJavaScript(ClassFile jc, Appendable out) {

    44         this.jc = jc;

    45         this.out = out;

    46     }

    48     /** Converts a given class file to a JavaScript version.

    49      * @param fileName the name of the file we are reading

    50      * @param classFile input stream with code of the .class file

    51      * @param out a {@link StringBuilder} or similar to generate the output to

    52      * @throws IOException if something goes wrong during read or write or translating

    53      */

    54     public static void compile(String fileName, InputStream classFile, Appendable out) throws IOException {

    55         ClassFile jc = new ClassFile(classFile, true);

    56         ByteCodeToJavaScript compiler = new ByteCodeToJavaScript(jc, out);

    57         for (Method m : jc.getMethods()) {

    58             if (m.isStatic()) {

    59                 compiler.generateStaticMethod(m);

    60             } else {

    61                 compiler.generateInstanceMethod(m);

    62             }

    63         }

    64         for (Variable v : jc.getVariables()) {

    65             if (v.isStatic()) {

    66                 compiler.generateStaticField(v);

    67             }

    68         }

    69         out.append("function java_lang_Object(){}\n"); // XXX temporary

    70         out.append("function java_lang_Object_consV(self){}\n"); // XXX temporary

    72         final String className = jc.getName().getExternalName().replace('.', '_');

    73         out.append("\nfunction ").append(className);

    74         out.append("() {");

    75         for (Method m : jc.getMethods()) {

    76             if (!m.isStatic()) {

    77                 compiler.generateMethodReference(m);

    78             }

    79         }

    80         for (Variable v : jc.getVariables()) {

    81             if (!v.isStatic()) {

    82                 out.append("\n  this." + v.getName() + " = 0;");

    83             }

    84         }

    85         out.append("\n  this.$instOf_").append(className).append(" = true;");

    86         out.append("\n}");

    87         ClassName sc = jc.getSuperClass();

    88         if (sc != null) {

    89             out.append("\n  ").append(className)

    90                .append(".prototype = new ").append(sc.getExternalName().replace('.', '_'));

    91         }

    92     }

    93     private void generateStaticMethod(Method m) throws IOException {

    94         out.append("\nfunction ").append(

    95             jc.getName().getExternalName().replace('.', '_')

    96         ).append('_').append(findMethodName(m));

    97         out.append('(');

    98         String space = "";

    99         List<Parameter> args = m.getParameters();

   100         for (int index = 0, i = 0; i < args.size(); i++) {

   101             out.append(space);

   102             out.append("arg").append(String.valueOf(index));

   103             space = ",";

   104             final String desc = args.get(i).getDescriptor();

   105             if ("D".equals(desc) || "J".equals(desc)) {

   106                 index += 2;

   107             } else {

   108                 index++;

   109             }

   110         }

   111         out.append(") {").append("\n");

   112         final Code code = m.getCode();

   113         int len = code.getMaxLocals();

   114         for (int index = args.size(), i = args.size(); i < len; i++) {

   115             out.append("  var ");

   116             out.append("arg").append(String.valueOf(i)).append(";\n");

   117         }

   118         out.append("  var stack = new Array(");

   119         out.append(Integer.toString(code.getMaxStack()));

   120         out.append(");\n");

   121         produceCode(code.getByteCodes());

   122         out.append("}");

   123     }

   125     private void generateMethodReference(Method m) throws IOException {

   126         final String name = findMethodName(m);

   127         out.append("\n  this.").append(name).append(" = ")

   128            .append(jc.getName().getExternalName().replace('.', '_'))

   129            .append('_').append(name).append(";");

   130     }

   132     private void generateInstanceMethod(Method m) throws IOException {

   133         out.append("\nfunction ").append(

   134             jc.getName().getExternalName().replace('.', '_')

   135         ).append('_').append(findMethodName(m));

   136         out.append("(arg0");

   137         String space = ",";

   138         List<Parameter> args = m.getParameters();

   139         for (int index = 1, i = 0; i < args.size(); i++) {

   140             out.append(space);

   141             out.append("arg").append(String.valueOf(index));

   142             final String desc = args.get(i).getDescriptor();

   143             if ("D".equals(desc) || "J".equals(desc)) {

   144                 index += 2;

   145             } else {

   146                 index++;

   147             }

   148         }

   149         out.append(") {").append("\n");

   150         final Code code = m.getCode();

   151         int len = code.getMaxLocals();

   152         for (int index = args.size(), i = args.size(); i < len; i++) {

   153             out.append("  var ");

   154             out.append("arg").append(String.valueOf(i + 1)).append(";\n");

   155         }

   156         out.append(";\n  var stack = new Array(");

   157         out.append(Integer.toString(code.getMaxStack()));

   158         out.append(");\n");

   159         produceCode(code.getByteCodes());

   160         out.append("}");

   161     }

   163     private void produceCode(byte[] byteCodes) throws IOException {

   164         out.append("\n  var gt = 0;\n  for(;;) switch(gt) {\n");

   165         for (int i = 0; i < byteCodes.length; i++) {

   166             int prev = i;

   167             out.append("    case " + i).append(": ");

   168             final int c = (byteCodes[i] + 256) % 256;

   169             switch (c) {

   170                 case bc_aload_0:

   171                 case bc_iload_0:

   172                 case bc_lload_0:

   173                 case bc_fload_0:

   174                 case bc_dload_0:

   175                     out.append("stack.push(arg0);");

   176                     break;

   177                 case bc_aload_1:

   178                 case bc_iload_1:

   179                 case bc_lload_1:

   180                 case bc_fload_1:

   181                 case bc_dload_1:

   182                     out.append("stack.push(arg1);");

   183                     break;

   184                 case bc_aload_2:

   185                 case bc_iload_2:

   186                 case bc_lload_2:

   187                 case bc_fload_2:

   188                 case bc_dload_2:

   189                     out.append("stack.push(arg2);");

   190                     break;

   191                 case bc_aload_3:

   192                 case bc_iload_3:

   193                 case bc_lload_3:

   194                 case bc_fload_3:

   195                 case bc_dload_3:

   196                     out.append("stack.push(arg3);");

   197                     break;

   198                 case bc_iload:

   199                 case bc_lload:

   200                 case bc_fload:

   201                 case bc_dload:

   202                 case bc_aload: {

   203                     final int indx = (byteCodes[++i] + 256) % 256;

   204                     out.append("stack.push(arg").append(indx + ");");

   205                     break;

   206                 }

   207                 case bc_astore_0:

   208                 case bc_istore_0:

   209                 case bc_lstore_0:

   210                 case bc_fstore_0:

   211                 case bc_dstore_0:

   212                     out.append("arg0 = stack.pop();");

   213                     break;

   214                 case bc_astore_1:

   215                 case bc_istore_1:

   216                 case bc_lstore_1:

   217                 case bc_fstore_1:

   218                 case bc_dstore_1:

   219                     out.append("arg1 = stack.pop();");

   220                     break;

   221                 case bc_astore_2:

   222                 case bc_istore_2:

   223                 case bc_lstore_2:

   224                 case bc_fstore_2:

   225                 case bc_dstore_2:

   226                     out.append("arg2 = stack.pop();");

   227                     break;

   228                 case bc_astore_3:

   229                 case bc_istore_3:

   230                 case bc_lstore_3:

   231                 case bc_fstore_3:

   232                 case bc_dstore_3:

   233                     out.append("arg3 = stack.pop();");

   234                     break;

   235                 case bc_iadd:

   236                 case bc_ladd:

   237                 case bc_fadd:

   238                 case bc_dadd:

   239                     out.append("stack.push(stack.pop() + stack.pop());");

   240                     break;

   241                 case bc_isub:

   242                 case bc_lsub:

   243                 case bc_fsub:

   244                 case bc_dsub:

   245                     out.append("{ var tmp = stack.pop(); stack.push(stack.pop() - tmp); }");

   246                     break;

   247                 case bc_imul:

   248                 case bc_lmul:

   249                 case bc_fmul:

   250                 case bc_dmul:

   251                     out.append("stack.push(stack.pop() * stack.pop());");

   252                     break;

   253                 case bc_idiv:

   254                 case bc_ldiv:

   255                     out.append("{ var tmp = stack.pop(); stack.push(Math.floor(stack.pop() / tmp)); }");

   256                     break;

   257                 case bc_fdiv:

   258                 case bc_ddiv:

   259                     out.append("{ var tmp = stack.pop(); stack.push(stack.pop() / tmp); }");

   260                     break;

   261                 case bc_iand:

   262                 case bc_land:

   263                     out.append("stack.push(stack.pop() & stack.pop());");

   264                     break;

   265                 case bc_ior:

   266                 case bc_lor:

   267                     out.append("stack.push(stack.pop() | stack.pop());");

   268                     break;

   269                 case bc_ixor:

   270                 case bc_lxor:

   271                     out.append("stack.push(stack.pop() ^ stack.pop());");

   272                     break;

   273                 case bc_iinc: {

   274                     final int varIndx = (byteCodes[++i] + 256) % 256;

   275                     final int incrBy = (byteCodes[++i] + 256) % 256;

   276                     if (incrBy == 1) {

   277                         out.append("arg" + varIndx).append("++;");

   278                     } else {

   279                         out.append("arg" + varIndx).append(" += " + incrBy).append(";");

   280                     }

   281                     break;

   282                 }

   283                 case bc_return:

   284                     out.append("return;");

   285                     break;

   286                 case bc_ireturn:

   287                 case bc_lreturn:

   288                 case bc_freturn:

   289                 case bc_dreturn:

   290                 case bc_areturn:

   291                     out.append("return stack.pop();");

   292                     break;

   293                 case bc_i2l:

   294                 case bc_i2f:

   295                 case bc_i2d:

   296                 case bc_l2i:

   297                     // max int check?

   298                 case bc_l2f:

   299                 case bc_l2d:

   300                 case bc_f2d:

   301                 case bc_d2f:

   302                     out.append("/* number conversion */");

   303                     break;

   304                 case bc_f2i:

   305                 case bc_f2l:

   306                 case bc_d2i:

   307                 case bc_d2l:

   308                     out.append("stack.push(Math.floor(stack.pop()));");

   309                     break;

   310                 case bc_i2b:

   311                 case bc_i2c:

   312                 case bc_i2s:

   313                     out.append("/* number conversion */");

   314                     break;

   315                 case bc_iconst_0:

   316                 case bc_dconst_0:

   317                 case bc_lconst_0:

   318                 case bc_fconst_0:

   319                     out.append("stack.push(0);");

   320                     break;

   321                 case bc_iconst_1:

   322                 case bc_lconst_1:

   323                 case bc_fconst_1:

   324                 case bc_dconst_1:

   325                     out.append("stack.push(1);");

   326                     break;

   327                 case bc_iconst_2:

   328                 case bc_fconst_2:

   329                     out.append("stack.push(2);");

   330                     break;

   331                 case bc_iconst_3:

   332                     out.append("stack.push(3);");

   333                     break;

   334                 case bc_iconst_4:

   335                     out.append("stack.push(4);");

   336                     break;

   337                 case bc_iconst_5:

   338                     out.append("stack.push(5);");

   339                     break;

   340                 case bc_ldc_w:

   341                 case bc_ldc2_w: {

   342                     int indx = readIntArg(byteCodes, i);

   343                     CPEntry entry = jc.getConstantPool().get(indx);

   344                     i += 2;

   345                     out.append("stack.push(" + entry.getValue() + ");");

   346                     break;

   347                 }

   348                 case bc_if_icmpeq: {

   349                     i = generateIf(byteCodes, i, "==");

   350                     break;

   351                 }

   352                 case bc_ifeq: {

   353                     int indx = i + readIntArg(byteCodes, i);

   354                     out.append("if (stack.pop() == 0) { gt = " + indx);

   355                     out.append("; continue; }");

   356                     i += 2;

   357                     break;

   358                 }

   359                 case bc_ifnonnull: {

   360                     int indx = i + readIntArg(byteCodes, i);

   361                     out.append("if (stack.pop()) { gt = " + indx);

   362                     out.append("; continue; }");

   363                     i += 2;

   364                     break;

   365                 }

   366                 case bc_ifnull: {

   367                     int indx = i + readIntArg(byteCodes, i);

   368                     out.append("if (!stack.pop()) { gt = " + indx);

   369                     out.append("; continue; }");

   370                     i += 2;

   371                     break;

   372                 }

   373                 case bc_if_icmpne:

   374                     i = generateIf(byteCodes, i, "!=");

   375                     break;

   376                 case bc_if_icmplt:

   377                     i = generateIf(byteCodes, i, ">");

   378                     break;

   379                 case bc_if_icmple:

   380                     i = generateIf(byteCodes, i, ">=");

   381                     break;

   382                 case bc_if_icmpgt:

   383                     i = generateIf(byteCodes, i, "<");

   384                     break;

   385                 case bc_if_icmpge:

   386                     i = generateIf(byteCodes, i, "<=");

   387                     break;

   388                 case bc_goto: {

   389                     int indx = i + readIntArg(byteCodes, i);

   390                     out.append("gt = " + indx).append("; continue;");

   391                     i += 2;

   392                     break;

   393                 }

   394                 case bc_invokeinterface:

   395                 case bc_invokevirtual:

   396                     i = invokeVirtualMethod(byteCodes, i);

   397                     break;

   398                 case bc_invokespecial:

   399                     i = invokeStaticMethod(byteCodes, i, false);

   400                     break;

   401                 case bc_invokestatic:

   402                     i = invokeStaticMethod(byteCodes, i, true);

   403                     break;

   404                 case bc_new: {

   405                     int indx = readIntArg(byteCodes, i);

   406                     CPClassInfo ci = jc.getConstantPool().getClass(indx);

   407                     out.append("stack.push(");

   408                     out.append("new ").append(ci.getClassName().getExternalName().replace('.','_'));

   409                     out.append(");");

   410                     i += 2;

   411                     break;

   412                 }

   413                 case bc_dup:

   414                     out.append("stack.push(stack[stack.length - 1]);");

   415                     break;

   416                 case bc_bipush:

   417                     out.append("stack.push(" + byteCodes[++i] + ");");

   418                     break;

   419                 case bc_getfield: {

   420                     int indx = readIntArg(byteCodes, i);

   421                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);

   422                     out.append(" stack.push(stack.pop().").append(fi.getFieldName()).append(");");

   423                     i += 2;

   424                     break;

   425                 }

   426                 case bc_getstatic: {

   427                     int indx = readIntArg(byteCodes, i);

   428                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);

   429                     out.append("stack.push(").append(fi.getClassName().getExternalName().replace('.', '_'));

   430                     out.append('_').append(fi.getFieldName()).append(");");

   431                     i += 2;

   432                     break;

   433                 }

   434                 case bc_putstatic: {

   435                     int indx = readIntArg(byteCodes, i);

   436                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);

   437                     out.append(fi.getClassName().getExternalName().replace('.', '_'));

   438                     out.append('_').append(fi.getFieldName()).append(" = stack.pop();");

   439                     i += 2;

   440                     break;

   441                 }

   442                 case bc_putfield: {

   443                     int indx = readIntArg(byteCodes, i);

   444                     CPFieldInfo fi = (CPFieldInfo) jc.getConstantPool().get(indx);

   445                     out.append("{ var v = stack.pop(); stack.pop().")

   446                        .append(fi.getFieldName()).append(" = v; }");

   447                     i += 2;

   448                     break;

   449                 }

   450                 case bc_instanceof: {

   451                     int indx = readIntArg(byteCodes, i);

   452                     CPClassInfo ci = jc.getConstantPool().getClass(indx);

   453                     out.append("stack.push(stack.pop().$instOf_")

   454                        .append(ci.getClassName().getExternalName().replace('.', '_'))

   455                        .append(" ? 1 : 0);");

   456                     i += 2;

   457                 }

   459             }

   460             out.append(" /*");

   461             for (int j = prev; j <= i; j++) {

   462                 out.append(" ");

   463                 final int cc = (byteCodes[j] + 256) % 256;

   464                 out.append(Integer.toString(cc));

   465             }

   466             out.append("*/\n");

   467         }

   468         out.append("  }\n");

   469     }

   471     private int generateIf(byte[] byteCodes, int i, final String test) throws IOException {

   472         int indx = i + readIntArg(byteCodes, i);

   473         out.append("if (stack.pop() ").append(test).append(" stack.pop()) { gt = " + indx);

   474         out.append("; continue; }");

   475         return i + 2;

   476     }

   478     private int readIntArg(byte[] byteCodes, int offsetInstruction) {

   479         final int indxHi = byteCodes[offsetInstruction + 1] << 8;

   480         final int indxLo = byteCodes[offsetInstruction + 2];

   481         return (indxHi & 0xffffff00) | (indxLo & 0xff);

   482     }

   484     private static int countArgs(String descriptor, boolean[] hasReturnType, StringBuilder sig) {

   485         int cnt = 0;

   486         int i = 0;

   487         Boolean count = null;

   488         int firstPos = sig.length();

   489         while (i < descriptor.length()) {

   490             char ch = descriptor.charAt(i++);

   491             switch (ch) {

   492                 case '(':

   493                     count = true;

   494                     continue;

   495                 case ')':

   496                     count = false;

   497                     continue;

   498                 case 'B':

   499                 case 'C':

   500                 case 'D':

   501                 case 'F':

   502                 case 'I':

   503                 case 'J':

   504                 case 'S':

   505                 case 'Z':

   506                     if (count) {

   507                         cnt++;

   508                         sig.append(ch);

   509                     } else {

   510                         hasReturnType[0] = true;

   511                         sig.insert(firstPos, ch);

   512                     }

   513                     continue;

   514                 case 'V':

   515                     assert !count;

   516                     hasReturnType[0] = false;

   517                     sig.insert(firstPos, 'V');

   518                     continue;

   519                 case 'L':

   520                     int next = descriptor.indexOf(';', i);

   521                     if (count) {

   522                         cnt++;

   523                         sig.append(ch);

   524                         sig.append(descriptor.substring(i, next).replace('/', '_'));

   525                     } else {

   526                         sig.insert(firstPos, descriptor.substring(i, next).replace('/', '_'));

   527                         sig.insert(firstPos, ch);

   528                         hasReturnType[0] = true;

   529                     }

   530                     i = next + 1;

   531                     continue;

   532                 case '[':

   533                     //arrays++;

   534                     continue;

   535                 default:

   536                     break; // invalid character

   537             }

   538         }

   539         return cnt;

   540     }

   542     private void generateStaticField(Variable v) throws IOException {

   543         out.append("\nvar ")

   544            .append(jc.getName().getExternalName().replace('.', '_'))

   545            .append('_').append(v.getName()).append(" = 0;");

   546     }

   548     private String findMethodName(Method m) {

   549         StringBuilder out = new StringBuilder();

   550         if ("<init>".equals(m.getName())) { // NOI18N

   551             out.append("consV"); // NOI18N

   552         } else {

   553             out.append(m.getName());

   554             outType(m.getReturnType(), out);

   555         }

   556         List<Parameter> args = m.getParameters();

   557         for (Parameter t : args) {

   558             outType(t.getDescriptor(), out);

   559         }

   560         return out.toString();

   561     }

   563     private String findMethodName(CPMethodInfo mi, int[] cnt, boolean[] hasReturn) {

   564         StringBuilder name = new StringBuilder();

   565         if ("<init>".equals(mi.getName())) { // NOI18N

   566             name.append("cons"); // NOI18N

   567         } else {

   568             name.append(mi.getName());

   569         }

   570         cnt[0] = countArgs(mi.getDescriptor(), hasReturn, name);

   571         return name.toString();

   572     }

   574     private int invokeStaticMethod(byte[] byteCodes, int i, boolean isStatic)

   575     throws IOException {

   576         int methodIndex = readIntArg(byteCodes, i);

   577         CPMethodInfo mi = (CPMethodInfo) jc.getConstantPool().get(methodIndex);

   578         boolean[] hasReturn = { false };

   579         int[] cnt = { 0 };

   580         String mn = findMethodName(mi, cnt, hasReturn);

   581         out.append("{ ");

   582         for (int j = cnt[0] - 1; j >= 0; j--) {

   583             out.append("var v" + j).append(" = stack.pop(); ");

   584         }

   586         if (hasReturn[0]) {

   587             out.append("stack.push(");

   588         }

   589         out.append(mi.getClassName().getInternalName().replace('/', '_'));

   590         out.append('_');

   591         out.append(mn);

   592         out.append('(');

   593         String sep = "";

   594         if (!isStatic) {

   595             out.append("stack.pop()");

   596             sep = ", ";

   597         }

   598         for (int j = 0; j < cnt[0]; j++) {

   599             out.append(sep);

   600             out.append("v" + j);

   601             sep = ", ";

   602         }

   603         out.append(")");

   604         if (hasReturn[0]) {

   605             out.append(")");

   606         }

   607         out.append("; }");

   608         i += 2;

   609         return i;

   610     }

   611     private int invokeVirtualMethod(byte[] byteCodes, int i)

   612     throws IOException {

   613         int methodIndex = readIntArg(byteCodes, i);

   614         CPMethodInfo mi = (CPMethodInfo) jc.getConstantPool().get(methodIndex);

   615         boolean[] hasReturn = { false };

   616         int[] cnt = { 0 };

   617         String mn = findMethodName(mi, cnt, hasReturn);

   618         out.append("{ ");

   619         for (int j = cnt[0] - 1; j >= 0; j--) {

   620             out.append("var v" + j).append(" = stack.pop(); ");

   621         }

   622         out.append("var self = stack.pop(); ");

   623         if (hasReturn[0]) {

   624             out.append("stack.push(");

   625         }

   626         out.append("self.");

   627         out.append(mn);

   628         out.append('(');

   629         out.append("self");

   630         for (int j = 0; j < cnt[0]; j++) {

   631             out.append(", ");

   632             out.append("v" + j);

   633         }

   634         out.append(")");

   635         if (hasReturn[0]) {

   636             out.append(")");

   637         }

   638         out.append("; }");

   639         i += 2;

   640         return i;

   641     }

   643     private void outType(final String d, StringBuilder out) {

   644         if (d.charAt(0) == 'L') {

   645             assert d.charAt(d.length() - 1) == ';';

   646             out.append(d.replace('/', '_').substring(0, d.length() - 1));

   647         } else {

   648             out.append(d);

   649         }

   650     }

   651 }

author	Jaroslav Tulach <jaroslav.tulach@apidesign.org>
	Thu, 20 Sep 2012 10:39:54 +0200
changeset 17	cb0cfba1b863
parent 16	6e8e00258234
child 18	361b76189f8d
permissions	-rw-r--r--