[llvm-dev] (Thin)LTO llvm build

[Teresa Johnson via llvm-dev]

On Mon, Oct 3, 2016 at 2:59 PM, Xinliang David Li <xinliangli at gmail.com>
wrote:

> Is -fsplit-stack option used anywhere? My wild guess is that with ld.bfd,
> the thinLTO link for the DSO does not bring in morestack.o from libgcc.a,
> but the hidden symbol is defined in lldb binary.
>

AFAICT, no - I had done "ninja -v" so I have all of the intermediate build
commands, and it doesn't show up in that.

I'll have to do some more digging to figure out why it is referenced from
liblldb.so in the ld.bfd case and not when using ld.gold

Teresa

David
>
> On Mon, Oct 3, 2016 at 1:54 PM, Teresa Johnson via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> Aha - finally reproduced! The difference is using ld.bfd not ld.gold.
>> With that I get the same failure (using 3.9 to build 3.9 sources):
>>
>> /usr/local/google/home/tejohnson/binutils_build/install/bin/ld:
>> bin/lldb-3.9.1: hidden symbol `__morestack' in
>> /usr/lib/gcc/x86_64-linux-gnu/4.8/libgcc.a(morestack.o) is referenced by
>> DSO
>> /usr/local/google/home/tejohnson/binutils_build/install/bin/ld: final
>> link failed: Bad value
>> clang-3.9: error: linker command failed with exit code 1 (use -v to see
>> invocation)
>> ninja: build stopped: subcommand failed.
>>
>> I am not sure what the official support story is for LLVMgold.so and
>> ld.bfd. As mentioned earlier, the LLVM site indicates it should use the
>> gold linker. Can you use that while I try to figure out whether this is
>> something that should be supported/working?
>>
>> Thanks,
>> Teresa
>>
>> On Mon, Oct 3, 2016 at 9:56 AM, Carsten Mattner <carstenmattner at gmail.com
>> > wrote:
>>
>>> On Mon, Oct 3, 2016 at 3:50 PM, Teresa Johnson <tejohnson at google.com>
>>> wrote:
>>> >
>>> > On Sun, Oct 2, 2016 at 4:02 AM, Carsten Mattner <
>>> carstenmattner at gmail.com> wrote:
>>> >>
>>> >> On Sun, Oct 2, 2016 at 6:41 AM, Teresa Johnson <tejohnson at google.com>
>>> wrote:
>>> > >
>>> > > > I use trunk, but it depends on how close to the bleeding edge you
>>> > > > are comfortable with. But like I said, I also tried bootstrapping
>>> > > > with 3.9 (both trunk as well as 3.9 sources) and couldn't
>>> reproduce.
>>> >>
>>> >> Hmm, so you're saying neither fails for you, right?
>>> >
>>> > Yes
>>>
>>> Okay. Do you mind focusing on the 3.9 branch? It's less of a moving
>>> target
>>> and lends itself more to figuring out what's failing for me.
>>>
>>> As soon as I get around to it, I'll send you my full configure and build
>>> steps as a shell script. Need to streamline it.
>>>
>>
>>
>>
>> --
>> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
>> 408-460-2413
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>


-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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