Re: [PATCH] In _IEEE_LIBM mode, use weak symbols instead of wrapper funcs [v3]

"Keith Packard" <[email protected]> Fri, 21 Sep 2018 13:58:55 -0700

Newsgroups	gmane.comp.lib.newlib
Message-ID	<[email protected]>

Craig Howland <[email protected]> writes:

> It's no difference than a weak alias--it requires object file support.  To quote 
> from the GCC manual about a function alias attribute (which is what the macro 
> ends up using), "This attribute requires assembler and object file support, and 
> may not be available on all targets."

It is different from weak in that it doesn't require any object file or
linker support. For instance, here's what the __strong_reference does in
e_acos.c:

	.globl	acos
	.set	acos,__ieee754_acos

Using __weak_reference does this instead:

	.weak acos
	.equ acos, __ieee754_acos

The GCC docs don't really talk about non-weak aliases at all which makes
me unhappy as it would be useful to know if the statement you quoted
refers to *all* aliases, or only weak aliases.

However, given the current GCC docs, we'll certainly want to use a
separate conditional instead of attempting to auto-detect this mode.

I'll add that, but I won't add any autotools mechanism to define it as I
cannot rebuild the configure scripts on Debian any longer.

I'm not getting a sense of whether you think this is a useful change
though; it seems like a fairly obvious optimization of the existing
feature to me, but perhaps you're finding it too complicated to be
useful upstream?

-- 
-keith

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