Re: [Caml-list] Exceptions and backtraces

[Anders Fugmann <anders@fugmann.net>]

Yes. Tail call optimization and inlining will limit the usability of the 
stack traces.

I assume that inlining can be disabled with -inline 0 (and it is not a 
problem for bytecode).

The tail call optimization pass is more problematic in terms of produced 
stack trace, and I don't see any good solution to this.

Maybe it would be possible to just count number of function calls within 
the same stack frame. The back trace would then print the function call 
counts in addition to the regular stack trace.
Another possibility would be to only perform TCO on recursive functions.

/Anders


On 09/10/2015 11:45 AM, Jesper Louis Andersen wrote:
>
> On Wed, Sep 9, 2015 at 9:59 PM, Anders Peter Fugmann <anders@fugmann.net
> <mailto:anders@fugmann.net>> wrote:
>
>     It just occurred to me that the functions I made are tail recursive
>     and which is why the middle function call is eliminated.
>
>
> Or even worse, tail calling. This, and aggressive inlining are the two
> things which most often rears its ugly head when hunting for why a piece
> of code is breaking some invariant. You have to "guess" at what the
> compiler did to the code base and reconstruct the code path from this.
>
> On the other hand, you don't want to lose either of those two optimizations.
>
> I agree it is worthwhile to document both behaviours.
>
>
> --
> J.