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Re: externally_visible and resoultion file
On Wed, Jun 9, 2010 at 7:43 PM, Cary Coutant <ccoutant@google.com> wrote:
>>> Yes, this is also what I saw without plugin. I just wonder why "vvvvv"
>>> is linked with plugin if resolution file is not used to eliminate need
>>> of externally_visible attribute here.
>>
>> Probably because of the same linker-plugin bug that causes bar
>> to be resolved.
>
> Just to make sure I understand the problem:
>
> - The IR file for a.c contains definitions for vvvvv and bar.
> - The linker identifies that both symbols are referenced from outside
> the LTO world (PREVAILING_DEF rather than PREVAILING_DEF_IRONLY), but
> gcc isn't (yet) reading that info from the resolution file.
> - WPA eliminates bar() and makes vvvvv static in the replacement object file.
> - There are still references to those symbols in b.o, which was
> compiled outside LTO.
> - The linker should be complaining about undefined symbols in both
> cases, but isn't (perhaps because it's still seeing defs left over
> from the IR files). The symbol bar has a value of 0, while the
> reference to vvvvv seems to have the right address.
>
> Is that about right? What you're expecting is a link-time error
> reporting both bar and vvvvv as undefined, right?
That's correct.
Richard.
> -cary
>