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Re: Mark va_start as nothrow

Jan Hubicka wrote:

> Thinking about this more, the non-call-exceptions and use of any of C++
> standard library is iffy.  It is not built with the flag and thus any
> kind of ICE will not be properly handled anyway.

It's not built that way by default.  Is it impossible to build it that way?

> One can not resonably
> expect sprintf to produce sane non-call-exception

If you don't control the run-time library, yes, that's true.

> Since -fnon-call-exceptions is really Java thingy, where C++ runtime is
> irrelevant, I am not sure how much better we need to be on builtins.
> If it seems, we can hope for some sanity here, I will add the NCE_LISTs.

People do use it with C and C++, but I don't know how much.  I think
va_arg is different from sprintf; va_arg is implemented entirely in bits
we control.

I wasn't sure from Richard's email if he was suggesting just ignoring
throw specifications in the presence of -fnon-call-exceptions.  I don't
know exactly what to say about that.  My first reaction is that the
exception generated by a memory fault when compiling with
-fnon-call-exceptions should result in a call to std::unexpected if
uncaught with in a region that has a throw-specification that does not
permit the exception.

Mark Mitchell
(650) 331-3385 x713

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