Add documentation about adjusting PC to Target::resume

[daniel5151]

Add documentation about adjusting PC to Target::resume

[daniel5151]

Ah, yes, I've definitely encountered something like this before. My first guess would be that you're not adjusting the PC correctly after a breakpoint is hit.

Here's the relevant line in the documentation:

https://sourceware.org/gdb/current/onlinedocs/gdb/Stop-Reply-Packets.html#swbreak-stop-reason

On some architectures, such as x86, at the architecture level, when a breakpoint instruction executes the program counter points at the breakpoint address plus an offset. On such targets, the stub is responsible for adjusting the PC to point back at the breakpoint address.

Try playing around with that, and if it's still not working, could you please return debug logs from GDB and gdbstub?
Specifically, call set debug remote 1 in GDB, and run your server with the environment variable RUST_LOG=gdbstub=trace (if possible, enabling the std feature would be good, as it will also log packet responses, not just incoming packets)

[daniel5151]

No problem! Glad you sorted it out 😄

I have a feeling this is going to be a fairly common stumbling block, so I'm going to re-open + rename this issue to remind myself to update the Target::resume docs with a note regarding adjusting the PC.

[jamcleod]

Wow you're 100% right! Funny enough I went off to fix the bug about the PC not updating properly immediately after submitting this issue. Thanks!!