support de-optimized kernel builds

Because of compiler optimization, it is not easy to match the current pc to its source line.
Therefore, even though we use `cgdb` to understand and debug Linux kernel, the source line on `cgdb` seems to be randomly jumped, which makes it unreliable.

No source files, tests, or entry points are identified. Start by reproducing the source-line jumps in cgdb while debugging the Linux kernel, then determine the intended de-optimized build path; done means cgdb reliably maps the current program counter to its source line.

Written by the indexing model from the issue text.