On Wednesday, 18 February 2015 at 00:14:55 UTC, deadalnix wrote:
On Tuesday, 17 February 2015 at 19:03:49 UTC, Chris Williams
wrote:
Every throwable function call could be assumed to have a typed
result (even void functions) and if, after the return, the
caller checks the type and detects that it was an error,
bubbles that up, then eventually you get to wherever the
catcher is.
But so basically, the current ABI doesn't support it and
there's no desire to change it? How do exceptions currently
happen, if not via some official ABI declaration of how
throwable methods interact with one another? The
compiler/linker determines where the catcher is and inserts
code to cut down the stack and perform a long jump all the way
back? If so, how do scope statements work?
This kind of stunt is taxing on the fast path. It can be
implemented as setjmp/longjmp but is more and more avoided in
favor of libunwind based solutions for languages that have code
running on unwinding.
libunwind based solution is slower to unwind, but is not very
taxing in the fast path (only prevent some optimizations to be
done like tail call).
This solution is a non starter perforamnce-wize for D.
I didn't mean it as a solution. As said, I was just looking for
an intro to the topic, so that I (and others) could meaningfully
contribute or at least understand the options. I'll look up
libunwind and, if that has enough info for me to grok it, create
a wiki page on the subject.
