Re: Autoconf tests, libtool symlist files, undefined behavior, and LTO

[Ralf Wildenhues]

Hello t66667,

* address@hidden wrote on Thu, Sep 23, 2010 at 03:01:31AM CEST:
> I don't know if my problem suites this description.

No, it doesn't.

> Currently installed libtool on this system is,
> ltmain.sh (GNU libtool) 2.2.6b
> 
> I recently tested the LTO feature of GCC (targeting windows) and I
> found it was unable to link due to the presence of duplicating lines
> of *crt* without compiling with -flto there were not such issues.
> 
> It seems that libtool is emitting dllcrt2, crtbegin, crtend all over
> again after the first crtend. In the following line.
> g++ lib64/dllcrt2.o lib64/crtbegin.o ...
> _alot_of_other_link_arguments_ ... lib64/crtend.o lib64/dllcrt2.o
> lib64/crtbegin.o lib64/crtend.o
> These last three duplicating .o arguments are causing errors.
> lib64/dllcrt2.o:crtdll.c:(.text+0x50): multiple definition of `_CRT_INIT'
> lib64/dllcrt2.o:crtdll.c:(.text+0x50): first defined here
> Is this a know issue?

You may have found a bug, or not, I cannot tell from the sparse
description you've given.  Please write to the bug-libtool at gnu.org
mailing list (no subscription required) with full details about which
GCC and Libtool versions you are using, after updating Libtool to 2.4 if
you are trying to use LTO with it, write how you configured the software
that fails to link, and please post the complete 'libtool --mode=link'
command that fails, including all of its output.

Then we will see further.  On the odd chance of turning up a new GCC
bug, we'll report back to the GCC bugzilla then.  But until then there
is no need to cross-post this to the GCC development mailing list.

Thank you.

Cheers,
Ralf