2 On rmsbolt

(Dated: 11 Oct 2023)

rmsbolt is an Emacs package for displaying in near-real time the disassembly of compiled code. It has a visual tagging system so you can walk through either the source or the disassembly and it highlights the corresponding part in the other.

A very intesting package, which can be used for understanding the compiler output, and the effect of optimization flags. The idea can be seen from the screengrabs at the reference below. https://gitlab.com/jgkamat/rmsbolt.

The original idea comes from Matt Godbolt’s Compiler Explorer project. (https://github.com/compiler-explorer/compiler-explorer). The rmsbolt Emacs packages has advantages due to its implementation in Emacs. The main advantage is it runs locally rather than on a server. It can be installed from the package archive MELPA.

The minimal example is to let rmsbolt create an example ’starter’ code with M-x rmsbolt-starter. Pick a language of your choice, I suggest C to get the key idea. Then run M-x rmsbolt Try changing the compiler optimization settings to see the difference, such as gcc -O0 and gcc -O3.

Conclusion: rmsbolt is an interesting tool for learning about actual implementations of programming languages.