Re: [PATCH] Add plugin interface to LD [2/4] Claim files and add symbols.

[Ralf Wildenhues <Ralf dot Wildenhues at gmx dot de>]

* Dave Korn wrote on Thu, Sep 23, 2010 at 08:25:42AM CEST:
> On 23/09/2010 06:36, Ralf Wildenhues wrote:
> > * Dave Korn wrote on Thu, Sep 23, 2010 at 07:31:41AM CEST:
> >> --- a/ld/Makefile.am
> >> +++ b/ld/Makefile.am
> >> @@ -1989,7 +1989,7 @@ if ENABLE_PLUGINS
> >>  noinst_LTLIBRARIES = libldtestplug.la
> >>  libldtestplug_la_SOURCES = testplug.c
> >>  libldtestplug_la_CFLAGS= -g -O2
> >> -libldtestplug_la_LDFLAGS = -no-undefined -rpath /nowhere
> >> +libldtestplug_la_LDFLAGS = -no-undefined -rpath /nowhere -Wl,$(LIBIBERTY)
> > 
> > Why the '-Wl,' prefix?  I'd have expected $(LIBIBERTY) to be added to
> > libldtestplug_la_LIBADD.
> 
>   libiberty isn't built under libtool control at all, AFAIK, and is only ever
> built as a static archive, so I was under the impression I've got to pass it
> around behind libtool's back like this.

Not because of that, no.

> > If you need to work around libtool warning about adding static library
> > deps to a shared library, then I suggest at least -Wc, rather than -Wl,
> > but still I think you will run into troubles on static-only systems.
> 
>   What kind of problems?

Ordering.  You can't rely on libtool expanding -Wl, link flags after the
objects, meaning that libiberty may not be picked up at all.  (With
static linking, objects and libraries are evaluated in a strict command
line order, so all needed libraries must come after objects that need
them.)

Cheers,
Ralf