Dumping the IR (--dump-ir)

The compilers never see the source you wrote: by the time a backend runs, the front end has inlined every top-level (load "..."), expanded the macros, spliced the libraries the program references, and lowered a Scheme file to the core forms. --dump-ir prints that final form -- the IR, one top-level form per line, in source order -- and exits without compiling or running:

$ cat greeting.lisp
(defmacro shout (s) `(concatenate 'string ,s "!"))
(print (shout "hello"))
$ rontolisp greeting.lisp --dump-ir
(PRINT (CONCATENATE (QUOTE STRING) "hello" "!"))

The dump is ordinary Common Lisp: feeding it back to rontolisp runs the same program. That makes the flag a diff tool for the front end -- what a macro expansion or the Scheme lowering really produced is one diff away, without reading bytecode or adding temporary prints.

The last expansion happens in the dump itself: a built-in macro call (cond, setf, unless, ...) is lowered to the core forms beneath it, the same expansion the interpreter performs at eval time and the compilers at codegen -- so what a built-in macro did is one diff too. A call whose name a local flet/macrolet/symbol-macrolet shadows, and a call whose lowering is the compile path's own runtime machinery (the condition designators, the definition forms), prints as it stands for the consumer to expand; quoted data is never entered. The lowered dump runs identically -- the CLI suite round-trips one.

The dump happens before any backend is chosen, so it is the same for every target; -o is refused beside the flag, the dump compiling nothing. The library splices a program triggers ride the dump too, so a dump of a program using scheme or vec: carries their definitions ahead of the program's own forms. Warnings print as on a compile, on standard error; the dump itself is the whole standard output.