Dwarf Exception Handling question

[David Nadlinger via Digitalmars-d]

On Monday, 23 November 2015 at 21:05:29 UTC, Walter Bright wrote:
> The code looks quite good. I've been trying to adjust things, 
> however, so there are no pushes and pops in the code, trying to 
> preallocate everything needed in the function prolog.

Wouldn't you still need to restore the stack before leaving the 
function (tail call in this case)?

For a single register, push/pop is probably still cheaper than 
setting up RBP and having the extra mov/sub.

> dmd rewrites try-catch-finally into try-{try-catch}-finally, 
> which makes it easier to generate code, because fewer special 
> cases and fewer bugs. I've become a big fan of that technique

Except that we actually need to flatten all the nesting into a 
single landing pad anyway. How would you do this in DMD? I didn't 
realize you could even have multiple EH table entries attached to 
a single code location.

  — David