

Porting rr to x86-64 - msiemens
https://blog.mozilla.org/nfroyd/2014/10/30/porting-rr-to-x86-64/

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saidajigumi
Wow, rr's a pretty slick tool. Definitely filed away for future use. Anyone
with use experience care to chime in about it?

rr also reminds me of when, ages ago, I first ran into the ocaml debugger's
ability to step forward and _step backward_. To borrow the modern cliché:
_mind blown_.

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lambda
I haven't used rr, but I have used GDB's built in record and replay ability.

GDB's was quite useful, but painfully slow; I had to do a good amount of
bisecting down to a small enough input to reproduce the issue without having
to wait ages to execute before it was usable. Once I did that, though, it let
me find the issue a lot sooner than I would have been able to otherwise.

rr promises to be substantially faster the GDB's record and replay; if so, I
imagine it will be quite useful, though it is only once or twice a year that I
actually have to debug a problem that these kinds of tools are relevant for.

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emmelaich
rr uses/enhances gdb, so I guess you mean faster than gdb alone?

(It wasn't clear to me until I followed a few links - I hadn't heard of rr.)

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lambda
Yes, I meant faster than gdb's native record and replay feature.

The nice thing about rr is that you can still use it with gdb, so you have the
full power of gdb along with close to native speed record and reply. Once the
x86-64 support is ready, it'll probably be a common tool for me.

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JD557
This seems like an incredibly useful tool, I can't believe I haven't heard
about it before.

Nevertheless, does anyone know if there's something like this for programs
compiled to the JVM? I've never used gdb to debug JVM code, but I expect that
it will not work well.

~~~
hga
As of a few years ago someone was working on such a system for the JVM and had
gotten quite some distance. Here it is:
[http://www.lambdacs.com/debugger/](http://www.lambdacs.com/debugger/)

A Google search
[https://www.google.com/search?q=java+backwards+debugger](https://www.google.com/search?q=java+backwards+debugger)
found some more hits.

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Aurel1us
Looks very promising. Did a quick set up but unfortunately some counters
couldn't be initialized on my VM.

