VS Code and terminal debugging interface for lapkt's Python Boost hybrid libraries.

[anubhav-cs]

A brief overview of how to set up a debug environment and perform debugging operations on the VS Code.

Note- In LAPKT, .vscode/launch.json has been configured to run python program with --wait_debug option. The option is present in lapkt python script and causes the program to wait for user input.

• Steps to debug using VS Code -
  • To compile lapkt libraries with debug symbols, run following command from the terminal. ./install.py --cmake_build_options Debug
  • Update Python launch option in .vscode/launch.json with required arguments.
  • Start Debugging(F5). Because of --wait_debug option, the program will stop for user input and also print a message "PID = <#######> ; Press a key to begin run..."
  • Go to Run tab in the VS Code. Then, select (gdb) Attach and run it. VS Code will ask for a process to attach gdb to. gdb has to be attached to the python program, which can searched using the PID printed by the previous step. After that, it will request for sudoer access(in a new terminal), which must be provided.
  • Add breakpoints in cxx files using VS Code.
  • Switch back to previous terminal (where the python program is waiting for a key input) and then press return key. The program will next pause at the instruction where it encounters one of the breakpoints.

A brief overview on how to use gdb from terminal to debug on any Linux OS.

• Steps to debug using linux terminal
  • Open a new terminal and run the following command to compile lapkt libraries with debug symbols. ./install.py --cmake_build_options Debug
  • Run lapkt with the option --wait_debug and other arguments as necessary. Because of --wait_debug option, the program will stop for user input and also print a message "PID = <#######> ; Press a key to begin run..."
  • Open a new terminal window and issue the following command. sudo gdb --pid=<PID>
  • In the terminal (where the python program is waiting for key input), press return - the program will not move forward as it is waiting for continue or cont command from the attached gdb.
  • Add the breakpoints as necessary in the gdb console and issue the cont command. It will next stop at the one of the breakpoints. An example on how to set breakpoints - br tarski_instantiator.cxx:401. This will cause program to pause at the instruction corresponding to line 401 in tarski_instantiator.cxx.
  • Deleting the breakpoint using del <breakpoint number> or just del, and then issuing cont will allow the program to execute freely until termination.

[anubhav-cs]

This feature is up and running. Relevant commits - 036316e and 01e9808

[anubhav-cs]

It should be noted that the addition of --with_debug option was a work around. Ideally, we should be able to attach gdb when the python program is paused on a breakpoint or at the start of the program(via the "stopOnEntry": true configuration in launch.json). However, it was observed that attaching gdb, while the python program was stopped in such a manner, caused issues in the symbol table loaded by gdb.