Re: avoid unnecessary register saves for setjmp

[Geert Bosch <bosch@gnat.com>]

On Nov 27, 2003, at 12:56, Zack Weinberg wrote:
>>> I'm going to take this opportunity to throw in a suggestion I've made
>>> before, which is that setjmp/longjmp should - always, not just when
>>> special variants are used - be converted by the front end into
>>> invocations of the exception-unwinding facility, which gives us tons
>>> more control.  (Obviously this only works with DWARF2 exception
>>> handling.)
>>
>> But what about backwards compatibility aka use of setjmp/longjmp
>> through libraries,
>
> This is a major stumbling block, yes.

Another issue is that traditional setjmp/longjmp is much faster than
exception-unwinding if a large number of longjmp calls is made.
I could agree with Zack that it is a good goal to have the default
be using DWARF2-based exception handling, but we should always have
the fallback option of using traditional setjmp/longjmp.

   -Geert