size of exception handling (Was: performance of exception handling)

[Moritz Strübe]

Hey.

Am 11.05.2020 um 15:59 schrieb Thomas Neumann via Gcc:
> In a way I am disagreeing with the paper, of course, in that I propose
> to make the existing exception mechanism faster instead of inventing a
> new exception mechanism. But what I agree on with P0709 is that it is
> unfortunate that many projects disable exceptions due to performance
> concerns. And I think the performance problems can be solved.

I just wanted to point out that Herbceptions do not only fix performance 
issues, but also code-size problems. While anything below 4GB of RAM is 
considered under-powered for a PC, typical deep embedded environments 
have something around 32k of program memory and 2K of ram. And even 
those running Linux often have around 32MB program memory and 8MB of 
RAM. Also most of these systems are very cost sensitive, so each byte 
matters. Therefore RTTI and exceptions are one of the main reasons why 
parts of the embedded community consider C++ unusable: They do some 
experiments using C++ and the code size explodes.  And even if you know 
what you are doing and turn interrupts and RTTI off, adding a 
std::nothrow to every "new" to do decent error handling is pretty 
annoying. Not mentioning the parts of the C++ library that don't provide 
exception-free error-handling.

So yes, improving the performance is nice, but ISO C++ will still be 
unusable for most computer systems: There are way more emdedded systems 
with less than 32MB program memory out there than PCs, Servers and 
mobile phones together.

Cheers
Morty

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