hg/bck2brwsr: src/main/java/org/apidesign/java4browser/ByteCodeToJavaScript.java@82772c96ec57

     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.CPLongInfo;

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

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

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

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

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

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

    35  *

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

    37  */

    38 public final class ByteCodeToJavaScript {

    39     private final ClassFile jc;

    40     private final Appendable out;

    42     private ByteCodeToJavaScript(ClassFile jc, Appendable out) {

    43         this.jc = jc;

    44         this.out = out;

    45     }

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

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

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

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

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

    52      */

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

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

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

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

    57             if (m.isStatic()) {

    58                 compiler.generateStaticMethod(m);

    59             }

    60         }

    61     }

    62     private void generateStaticMethod(Method m) throws IOException {

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

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

    65         ).append('_').append(

    66             m.getName()

    67         );

    68         out.append(m.getReturnType());

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

    70         for (Parameter t : args) {

    71             out.append(t.getDescriptor());

    72         }

    73         out.append('(');

    74         String space = "";

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

    76             out.append(space);

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

    78             space = ",";

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

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

    81                 index += 2;

    82             } else {

    83                 index++;

    84             }

    85         }

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

    87         final Code code = m.getCode();

    88         int len = code.getMaxLocals();

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

    90             out.append("  var ");

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

    92         }

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

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

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

    96         produceCode(code.getByteCodes());

    97         out.append("}");

    98     }

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

   101         out.append("\nvar gt = 0;\nfor(;;) switch(gt) {\n");

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

   103             int prev = i;

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

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

   106             switch (c) {

   107                 case bc_aload_0:

   108                 case bc_iload_0:

   109                 case bc_lload_0:

   110                 case bc_fload_0:

   111                 case bc_dload_0:

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

   113                     break;

   114                 case bc_aload_1:

   115                 case bc_iload_1:

   116                 case bc_lload_1:

   117                 case bc_fload_1:

   118                 case bc_dload_1:

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

   120                     break;

   121                 case bc_aload_2:

   122                 case bc_iload_2:

   123                 case bc_lload_2:

   124                 case bc_fload_2:

   125                 case bc_dload_2:

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

   127                     break;

   128                 case bc_aload_3:

   129                 case bc_iload_3:

   130                 case bc_lload_3:

   131                 case bc_fload_3:

   132                 case bc_dload_3:

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

   134                     break;

   135                 case bc_iload:

   136                 case bc_lload:

   137                 case bc_fload:

   138                 case bc_dload:

   139                 case bc_aload: {

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

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

   142                     break;

   143                 }

   144                 case bc_astore_0:

   145                 case bc_istore_0:

   146                 case bc_lstore_0:

   147                 case bc_fstore_0:

   148                 case bc_dstore_0:

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

   150                     break;

   151                 case bc_astore_1:

   152                 case bc_istore_1:

   153                 case bc_lstore_1:

   154                 case bc_fstore_1:

   155                 case bc_dstore_1:

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

   157                     break;

   158                 case bc_astore_2:

   159                 case bc_istore_2:

   160                 case bc_lstore_2:

   161                 case bc_fstore_2:

   162                 case bc_dstore_2:

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

   164                     break;

   165                 case bc_astore_3:

   166                 case bc_istore_3:

   167                 case bc_lstore_3:

   168                 case bc_fstore_3:

   169                 case bc_dstore_3:

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

   171                     break;

   172                 case bc_iadd:

   173                 case bc_ladd:

   174                 case bc_fadd:

   175                 case bc_dadd:

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

   177                     break;

   178                 case bc_isub:

   179                 case bc_lsub:

   180                 case bc_fsub:

   181                 case bc_dsub:

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

   183                     break;

   184                 case bc_imul:

   185                 case bc_lmul:

   186                 case bc_fmul:

   187                 case bc_dmul:

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

   189                     break;

   190                 case bc_idiv:

   191                 case bc_ldiv:

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

   193                     break;

   194                 case bc_fdiv:

   195                 case bc_ddiv:

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

   197                     break;

   198                 case bc_iand:

   199                 case bc_land:

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

   201                     break;

   202                 case bc_ior:

   203                 case bc_lor:

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

   205                     break;

   206                 case bc_ixor:

   207                 case bc_lxor:

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

   209                     break;

   210                 case bc_iinc: {

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

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

   213                     if (incrBy == 1) {

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

   215                     } else {

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

   217                     }

   218                     break;

   219                 }

   220                 case bc_ireturn:

   221                 case bc_lreturn:

   222                 case bc_freturn:

   223                 case bc_dreturn:

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

   225                     break;

   226                 case bc_i2l:

   227                 case bc_i2f:

   228                 case bc_i2d:

   229                 case bc_l2i:

   230                     // max int check?

   231                 case bc_l2f:

   232                 case bc_l2d:

   233                 case bc_f2d:

   234                 case bc_d2f:

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

   236                     break;

   237                 case bc_f2i:

   238                 case bc_f2l:

   239                 case bc_d2i:

   240                 case bc_d2l:

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

   242                     break;

   243                 case bc_i2b:

   244                 case bc_i2c:

   245                 case bc_i2s:

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

   247                     break;

   248                 case bc_iconst_0:

   249                 case bc_dconst_0:

   250                 case bc_lconst_0:

   251                 case bc_fconst_0:

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

   253                     break;

   254                 case bc_iconst_1:

   255                 case bc_lconst_1:

   256                 case bc_fconst_1:

   257                 case bc_dconst_1:

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

   259                     break;

   260                 case bc_iconst_2:

   261                 case bc_fconst_2:

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

   263                     break;

   264                 case bc_iconst_3:

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

   266                     break;

   267                 case bc_iconst_4:

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

   269                     break;

   270                 case bc_iconst_5:

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

   272                     break;

   273                 case bc_ldc_w:

   274                 case bc_ldc2_w: {

   275                     int indx = readIntArg(byteCodes, i);

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

   277                     i += 2;

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

   279                     break;

   280                 }

   281                 case bc_if_icmpeq: {

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

   283                     break;

   284                 }

   285                 case bc_ifeq: {

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

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

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

   289                     i += 2;

   290                     break;

   291                 }

   292                 case bc_if_icmpne:

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

   294                     break;

   295                 case bc_if_icmplt:

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

   297                     break;

   298                 case bc_if_icmple:

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

   300                     break;

   301                 case bc_if_icmpgt:

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

   303                     break;

   304                 case bc_if_icmpge:

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

   306                     break;

   307                 case bc_goto: {

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

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

   310                     i += 2;

   311                     break;

   312                 }

   313                 case bc_invokestatic: {

   314                     int methodIndex = readIntArg(byteCodes, i);

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

   316                     boolean[] hasReturn = { false };

   317                     StringBuilder signature = new StringBuilder();

   318                     int cnt = countArgs(mi.getDescriptor(), hasReturn, signature);

   320                     if (hasReturn[0]) {

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

   322                     }

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

   324                     out.append('_');

   325                     out.append(mi.getName());

   326                     out.append(signature.toString());

   327                     out.append('(');

   328                     String sep = "";

   329                     for (int j = 0; j < cnt; j++) {

   330                         out.append(sep);

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

   332                         sep = ", ";

   333                     }

   334                     out.append(")");

   335                     if (hasReturn[0]) {

   336                         out.append(")");

   337                     }

   338                     out.append(";");

   339                     i += 2;

   340                     break;

   341                 }

   342                 case bc_new: {

   343                     int indx = readIntArg(byteCodes, i);

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

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

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

   347                     out.append("());");

   348                     i += 2;

   349                     break;

   350                 }

   351                 case bc_dup:

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

   353                     break;

   354                 case bc_bipush:

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

   356                     break;

   357                 case bc_invokevirtual:

   358                 case bc_invokespecial: {

   359                     int indx = readIntArg(byteCodes, i);

   360                     CPMethodInfo mi = (CPMethodInfo) jc.getConstantPool().get(indx);

   361                     out.append("{ var tmp = stack.pop(); tmp." + mi.getMethodName() + "(); }");

   362                     i += 2;

   363                     break;

   364                 }

   365                 case bc_getfield: {

   366                     int indx = readIntArg(byteCodes, i);

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

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

   369                     i += 2;

   370                     break;

   371                 }

   373             }

   374             out.append(" /*");

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

   376                 out.append(" ");

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

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

   379             }

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

   381         }

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

   383     }

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

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

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

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

   389         return i + 2;

   390     }

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

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

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

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

   396     }

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

   399         int cnt = 0;

   400         int i = 0;

   401         Boolean count = null;

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

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

   404             switch (ch) {

   405                 case '(':

   406                     count = true;

   407                     continue;

   408                 case ')':

   409                     count = false;

   410                     continue;

   411                 case 'B':

   412                 case 'C':

   413                 case 'D':

   414                 case 'F':

   415                 case 'I':

   416                 case 'J':

   417                 case 'S':

   418                 case 'Z':

   419                     if (count) {

   420                         cnt++;

   421                         sig.append(ch);

   422                     } else {

   423                         hasReturnType[0] = true;

   424                         sig.insert(0, ch);

   425                     }

   426                     continue;

   427                 case 'V':

   428                     assert !count;

   429                     hasReturnType[0] = false;

   430                     sig.insert(0, 'V');

   431                     continue;

   432                 case 'L':

   433                     i = descriptor.indexOf(';', i);

   434                     if (count) {

   435                         cnt++;

   436                     } else {

   437                         hasReturnType[0] = true;

   438                     }

   439                     continue;

   440                 case '[':

   441                     //arrays++;

   442                     continue;

   443                 default:

   444                     break; // invalid character

   445             }

   446         }

   447         return cnt;

   448     }

   449 }

author	Jaroslav Tulach <jaroslav.tulach@apidesign.org>
	Sat, 15 Sep 2012 22:12:49 +0200
changeset 8	82772c96ec57
parent 7	5b135a2f2de3
child 9	0cab1e07e677
permissions	-rw-r--r--