[LLVMdev] Unwind behaviour in Clang/LLVM

Renato Golin
Fri, 07 Feb 2014 09:35:17 -0000

On 7 February 2014 00:19, Richard Smith <richard at metafoo.co.uk> wrote:

> This (-fexceptions and -g imply -funwind-tables) seems like it's
probably
> the right thing for most targets. With SjLj exceptions, -fexceptions
> probably doesn't need -funwind-tables.
>

Thanks, I think that's the general consensus, yes.

Do we have such logic in Clang at the moment?

My original point was that the back-end shouldn't try to guess, so
front-ends should pass this information down, either via function
attributes or flags. Attributes would be better for multi-stage compilation
process, but if the default target description is shared between front and
back ends, than we might not need this, and flags become the preferred
method.

This is another reason to proceed with a separate library for target
description (that deals with triples, -m flags, defaults, etc), to be used
by both front and back ends, so then we don't have to worry about changing
all sides whenever a default changes.

cheers,
--renato
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