Building Patched MARS: Generic Typing Problem

Question

Building Patched MARS: Generic Typing Problem

thomasrussellmurphy opened this issue 9 years ago · comments

Thomas Russell Murphy commented 9 years ago

Re-building MARS encountered these errors in part of the Sockets implementation.

mars-sockets/mars/mips/instructions/syscalls/Sockets.java:21: illegal start of type
    private static ArrayList<ServerSocket> serverSockets = new ArrayList<>();
                                                                         ^
mars-sockets/mars/mips/instructions/syscalls/Sockets.java:22: illegal start of type
    private static ArrayList<Socket> sockets = new ArrayList<>();
                                                             ^
mars-sockets/mars/mips/instructions/syscalls/Sockets.java:25: illegal start of type
        serverSockets = new ArrayList<>();
                                      ^
mars-sockets/mars/mips/instructions/syscalls/Sockets.java:26: illegal start of type
        sockets = new ArrayList<>();
                                ^
4 errors

Thomas Russell Murphy · Answer 1 · Fri Mar 20 2015 21:37:17 GMT+0800 (China Standard Time)

Using Mars4_5-SockMod.jar as created with the above error to run the example gives the error:

Error in [...]/yams/socket-examples.asm line 109->67: Runtime exception at 0x00400080: invalid or unimplemented syscall service: 110

Additional information: OSX 10.9 running Java 8 Update 40.

Stephen Brennan · Answer 2 · Fri Mar 20 2015 22:33:47 GMT+0800 (China Standard Time)

It looks like a Java 6/7 diamond operator issue. If I had to guess, I'd say that Java 8 is just your JRE version, and you have an older JDK installed. Try running javac -version to verify.

We could get rid of the diamond inference to make it compatible with Java 6. If we accept my last pull request, I have a new one that gets rid of the patch and instead keeps the Java files in a directory, so we can pretty easily edit them with out dealing with the diff/patch format. Then we could make it Java 6 compatible, if it's a big enough issue.

Thomas Russell Murphy · Answer 3 · Fri Mar 20 2015 22:59:39 GMT+0800 (China Standard Time)

Confirmed old JDK. javac 1.6.0_65
Installing new JDK. However, shouldn't the generic instantiation include type parameter(s)?

Stephen Brennan · Answer 4 · Sat Mar 21 2015 00:10:18 GMT+0800 (China Standard Time)

Java 7 introduces diamond inference, which allows the type parameter to be omitted. We can modify the code to not use diamond inference, but the best way to do so would be to accept #3, and then I'll push my branch containing java files instead of the patch, and then we can modify the code.

Thomas Russell Murphy · Answer 5 · Sat Mar 21 2015 01:00:42 GMT+0800 (China Standard Time)

Well, this would break compatibility with aged MARS compatibility back to 1.5. However, being current should be fine.
Confirmed JDK 8u40 operation of the script.

Stephen Brennan · Answer 6 · Sat Mar 21 2015 01:05:39 GMT+0800 (China Standard Time)

So, may we merge #3?

Thomas Russell Murphy · Answer 7 · Sat Mar 21 2015 01:11:20 GMT+0800 (China Standard Time)

Closing issue as wontfix, require Java 7+.