How to native debug Java on macOS?

[Chris Plummer]

On 9/9/19 9:57 AM, Alexander Miloslavskiy wrote:
>> Have you tried putting these two lines in your ~/.lldbinit file?
>> process handle -s false SIGSEGV
>> process handle -s false SIGBUS
>
> Hmm, these seem to work...
>
> Previously, on two different occasions, I spent a couple hours trying 
> to get LLDB to work, also trying these very same commands, but failed. 
> Back then I was stuck on EXC_BAD_ACCESS, from which I couldn't 
> continue - it simply reoccurred again.
>
> However, this time it works. If for example I run these:
>     process handle --pass true --stop false SIGSEGV
>     process handle --pass true --stop false SIGBUS
>
> Then LLDB successfully skips all exceptions and my application runs as 
> intended. Not sure why I was blocked previously.
>
> Thanks!
>
I went down this path last week and never did get it working, even with 
the above, so I'm not sure why it is suddenly working for you. I'm on 
xcode 10.2.1. Maybe 10.3 fixes this.

The lldb handling of EXC_BAD_ACCESS seems to be a known issue. lldb 
processes the EXC_BAD_ACCESS, not allowing it to eventually be consumed 
and converted to a SIGSEGV or SIGBUS (I assume the pthread library does 
this). Thus it never even gets to the part of lldb that cares that you 
did a "process handle" for SIGSEGV. Here's one case in point of a user 
running into this problem:

https://stackoverflow.com/questions/26829119/how-to-make-lldb-ignore-exc-bad-access-exception

And bugs filed:

https://bugs.llvm.org/show_bug.cgi?id=40669
https://bugs.llvm.org/show_bug.cgi?id=22868

The only solution I've found is to run with -Xint.

And two things to consider with the "process handle" commands. The first 
is it only impacts the current process. When you relaunch you need to 
execute them again. This brings us to the second issue which is putting 
"process handle" commands in your .lldbinit is pointless since you don't 
even have a process at that point.

cheers,

Chris