#Is there a tool that works as debugger for JVM Bytecode or something that focuses on IJVM too?

10 messages · Page 1 of 1 (latest)

cedar plaza
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Long Version of my Question:
Ello, I need some help with IJVM (the simplified JVM architecture from a guy named Tanenbaum).
I need to learn how to use it and so on for my ComputerArchitecture module, the lectures are really hard to listen to and there does not seem to be so much informationen about it in video form. This is why I played with JVM and noticed how it does some operations yada yada. Now, I want to see if there is a tool that would show each step of what the JVM does in real time. Like I hava the following code:

         0: bipush        69
         2: istore_0
         3: bipush        12
         5: istore_1
         6: iload_0
         7: iload_1
         8: iadd
         9: istore_2
        10: iload_0
        11: iload_1
        12: imul
        13: istore_3
        14: iload_0
        15: iload_1
        16: idiv
        17: istore        4
        19: iload_0
        20: iload_1
        21: irem
        22: istore        5

It would be very cool to see what the stack and so one does in real life to understand it better.

languid runeBOT
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ivory loom
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I think that the JVM APIs might be using line numbers for the debugging capabilities. I recently worked on an Eclipse feature that basically allows debugging using the bytecode instructions but that also shows the variables and not stack information (and runs multiple instructions together)

531917319-38b942c4-c387-4d8d-be33-525f03c1e4a1.png
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but the second part seems interesting:

Step to the next source line unless there is no line number information in which case a MIN step is done instead.
It seems like if you remove the line number table (e.g. by compiling with -g:none), it will step through the individual bytecode instructions one by one

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I think that my addition to Eclipse might work with that but it would be a bit annoying to set up (needing to build Eclipse instead of just installing it) and it would show variables and not elements on the stack

cedar plaza
languid runeBOT
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rare flare