Re: How do i debug --no-inline or --full-tailcalls options?

[OKUMURA Yuki <mjt@cltn.org>]

Ah, thanks for the comments!

2016-02-11 23:01 GMT+09:00 Per Bothner <per@bothner.com>:
- snip -
> Why do you want to use --no-inlining?  One advantage I can see is beter
> stack traces (at least when --no-full-tailcalls).  It might be reasonable to
> retrict --no-inlining's effect to "normal" functions.

Use of --no-inline is just because it (accidentally) solved another problem:
(https://github.com/okuoku/yuni/issues/34)

I don't fully understand what is happening on that issue yet;
with --full-tailcalls and without --no-inline,
Kawa seems to skip some procedures when its result is not
consumed at all. (ie. every skipped procedures were wrapper around SET!)

I prepared (somewhat) minified program which exhibits the problem:

https://gist.github.com/okuoku/d5cba6f31b781db911aa

The code prepares 2 vectors which hold some data but when
I move some setters into a R7RS library, these setters are
mysteriously "skipped" and a vector field would left uninitialized.

Without --full-tailcall nor --no-inline, it works fine:

$ java kawa.repl --r7rs check3.scm
(SET!-CALLED: 0 test)
(SET!-CALLED: 1 #<procedure testfunc>)
(SET!-CALLED: 0 #(test #<procedure testfunc>))
(SET!-CALLED: 1 (INIT1 . INIT2))
(#(test #<procedure testfunc>) ("INIT1" . "INIT2"))

but with --full-tailcall, a SET!-CALLED message is missing;

$ java kawa.repl --r7rs --full-tailcalls check3.scm
(SET!-CALLED: 0 test)
(SET!-CALLED: 1 #<procedure testfunc>)
(SET!-CALLED: 1 (INIT1 . INIT2))
("UNINITIALIZED_x" ("INIT1" . "INIT2"))

this means a line here★

(define (make-minidispatch-obj class param)
  (let ((obj (make-minitype-obj)))
   (baseset! obj 0 class) ★
   (baseset! obj 1 param)
   obj))))

was skipped.


The problem is gone in case we added --no-inline:

$ java kawa.repl --r7rs --full-tailcalls --no-inline check3.scm
(SET!-CALLED: 0 test)
(SET!-CALLED: 1 #<procedure testfunc>)
(SET!-CALLED: 0 #(test #<procedure testfunc>))
(SET!-CALLED: 1 (INIT1 . INIT2))
(#(test #<procedure testfunc>) ("INIT1" . "INIT2"))

This is why I ended up specifying --no-inline.

I suspect this behaviour is backend's problem since when I merged
explicit libraries into a module, problem would just disappear.