Issue with JavaCC generate code: GOTO code without target loop/block.

[JWood48]

I have a custom grammar in javacc and would like to convert it to wasm, but I get the error:

> GOTO code without target loop/block. Jump from 442 to 55 at gantt.cq.parser.CQParserTokenManager.getNextToken(CQParserTokenManager.java:2078)

The specific getNextToken function is:

public Token getNextToken() 
{
  Token matchedToken;
  int curPos = 0;

  EOFLoop :
  for (;;)
  {
   try
   {
      curChar = input_stream.BeginToken();
   }
   catch(Exception e)
   {
      jjmatchedKind = 0;
      jjmatchedPos = -1;
      matchedToken = jjFillToken();
      return matchedToken;
   }
   image = jjimage;
   image.setLength(0);
   jjimageLen = 0;

   for (;;)
   {
     switch(curLexState)
     {
       case 0:
         try { input_stream.backup(0);
            while (curChar <= 32 && (0x100003600L & (1L << curChar)) != 0L)
               curChar = input_stream.BeginToken();
         }
         catch (java.io.IOException e1) { continue EOFLoop; }
         jjmatchedKind = 0x7fffffff;
         jjmatchedPos = 0;
         curPos = jjMoveStringLiteralDfa0_0();
         break;
       case 1:
         jjmatchedKind = 0x7fffffff;
         jjmatchedPos = 0;
         curPos = jjMoveStringLiteralDfa0_1();
         if (jjmatchedPos == 0 && jjmatchedKind > 13)
         {
            jjmatchedKind = 13;
         }
         break;
       case 2:
         jjmatchedKind = 0x7fffffff;
         jjmatchedPos = 0;
         curPos = jjMoveStringLiteralDfa0_2();
         if (jjmatchedPos == 0 && jjmatchedKind > 13)
         {
            jjmatchedKind = 13;
         }
         break;
     }
     if (jjmatchedKind != 0x7fffffff)
     {
        if (jjmatchedPos + 1 < curPos)
           input_stream.backup(curPos - jjmatchedPos - 1);
        if ((jjtoToken[jjmatchedKind >> 6] & (1L << (jjmatchedKind & 077))) != 0L)
        {
           matchedToken = jjFillToken();
       if (jjnewLexState[jjmatchedKind] != -1)
         curLexState = jjnewLexState[jjmatchedKind];
           return matchedToken;
        }
        else if ((jjtoSkip[jjmatchedKind >> 6] & (1L << (jjmatchedKind & 077))) != 0L)
        {
           SkipLexicalActions(null);
         if (jjnewLexState[jjmatchedKind] != -1)
           curLexState = jjnewLexState[jjmatchedKind];
           continue EOFLoop;
        }
        jjimageLen += jjmatchedPos + 1;
      if (jjnewLexState[jjmatchedKind] != -1)
        curLexState = jjnewLexState[jjmatchedKind];
        curPos = 0;
        jjmatchedKind = 0x7fffffff;
        try {
           curChar = input_stream.readChar();
           continue;
        }
        catch (java.io.IOException e1) { }
     }
     int error_line = input_stream.getEndLine();
     int error_column = input_stream.getEndColumn();
     String error_after = null;
     boolean EOFSeen = false;
     try { input_stream.readChar(); input_stream.backup(1); }
     catch (java.io.IOException e1) {
        EOFSeen = true;
        error_after = curPos <= 1 ? "" : input_stream.GetImage();
        if (curChar == '\n' || curChar == '\r') {
           error_line++;
           error_column = 0;
        }
        else
           error_column++;
     }
     if (!EOFSeen) {
        input_stream.backup(1);
        error_after = curPos <= 1 ? "" : input_stream.GetImage();
     }
     throw new TokenMgrError(EOFSeen, curLexState, error_line, error_column, error_after, curChar, TokenMgrError.LEXICAL_ERROR);
   }
  }
}

The line numbers do not match, but the referenced ´continue´ statement is in the last half of the code above:

        try {
           curChar = input_stream.readChar();
           continue;
        }

[Horcrux7]

• Do you use the latest snapshot from Jitpack? if not then try it.
• Where can I find binaries for reproduction (maven artifact name)?

[JWood48]

Created a project here to reproduce, but cant even get the basic example working, what am i doing wrong?

https://github.com/JWood48/JWebAssemblyTest

gradle wasm gives the following error:

$ gradle wasm

> Task :app:wasm FAILED
        compiler: jwebassembly-master-SNAPSHOT.jar
> WASM compile failed with: Native methods cannot be compiled to WebAssembly: java/lang/ref/Reference.refersTo0(Ljava/lang/Object;)Z
If you want to use classes with native code, you must use a library that implements these native methods, such as 'de.inetsoftware:jwebassembly-api:+' or implements this native method self.
        at java.lang.ref.Reference.refersTo0(Reference.java)

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:wasm'.
> Native methods cannot be compiled to WebAssembly: java/lang/ref/Reference.refersTo0(Ljava/lang/Object;)Z
  If you want to use classes with native code, you must use a library that implements these native methods, such as 'de.inetsoftware:jwebassembly-api:+' or implements this native method self.
        at java.lang.ref.Reference.refersTo0(Reference.java)

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s
2 actionable tasks: 2 executed

[Horcrux7]

WASM compile failed with: Native methods cannot be compiled to WebAssembly: java/lang/ref/Reference.refersTo0(Ljava/lang/Object;)Z

This error look like that you use a higher Java version. Currently only with Java 8 you can use Strings.

[JWood48]

Ok, i am not able to downgrade unfortunately... when will Strings be supported for java 11?

[Horcrux7]

First I will fix all compiler errors (not API errors) with Java 8. Then I will take a look at Java 11. I have no idea how many errors I will find and that I have no idea how long it will take. Can be a month or multiple years.

With compiler error I means thinks like the original error message GOTO code without target loop/block. which are result of misinterpreting the Java byte code.

A missing native method is an API error. You can fix it self: https://github.com/i-net-software/JWebAssembly/wiki/Compiler-Errors-and-Problems and make a PR.

Alternative you can ignore it with ignoreNative = true and convert it to a possible runtime error.