llvm dev - May 2013 - [LLVMdev] link native code compiled by llvm and gcc?

Hi,

Is it possible to link native codes generated by different compiler?

the usecase could be:
Linux kernel compiled by gcc want to load kernel module compiled by Clang
(I know there have some problem to compile kernel by Clang currently,
but ignore those problem in here)

I just concern about the call conversion problem, and compatibility
between gcc and clang.

Thanks

.jovi

Hi Jovi,
> Is it possible to link native codes generated by different compiler?
It should be. Clang aims to be GCC-compatible (and certainly in ABI
issues on a given platform like Linux). Any issues would be considered
bugs and we'd like to know about them.

Cheers.

Tim.

On Fri, May 3, 2013 at 11:17 PM, Tim Northover <t.p.northover at
gmail.com> wrote:
> Hi Jovi,
>
>> Is it possible to link native codes generated by different compiler?
>
> It should be. Clang aims to be GCC-compatible (and certainly in ABI
> issues on a given platform like Linux). Any issues would be considered
> bugs and we'd like to know about them.
>
> Cheers.
>
> Tim.
Thanks Tim, I got it now.

On Fri, May 03, 2013 at 11:11:30PM +0800, Jovi Zhang
wrote:
> Hi,
> 
> Is it possible to link native codes generated by different compiler?
> 
> the usecase could be:
> Linux kernel compiled by gcc want to load kernel module compiled by Clang
> (I know there have some problem to compile kernel by Clang currently,
> but ignore those problem in here)
> 
> I just concern about the call conversion problem, and compatibility
> between gcc and clang.
Hi Jovi,
It can be complicated. Many distributions patch gcc, the kernel, and the
entire tool chain. A good example is RedHat, which applies many many patches
to the kernel and the tool chain, including gcc. I believe embedded releases
are similar. The canonical kernel releases are only tested on specific canonical
versions of gcc. While I am certain you can realize this goal, you might run
into
some subtle problems. I would start by auditing the tool chains and kernels you
are
using, to understand any changes they have made downstream from the canonical
kernel
and gcc releases. In the case of RedHat, I believe they require you to build the
kernel with their tool chain. They will not support any modifications to the
build
process or the kernel. So, in a situation such as you describe, you are likely
on
your own.

enjoy,
Karen
-- 
Karen Shaeffer
Neuralscape, Mountain View, CA 94040

On Sat, May 4, 2013 at 1:54 AM, Karen Shaeffer <shaeffer at
neuralscape.com> wrote:
> On Fri, May 03, 2013 at 11:11:30PM +0800, Jovi Zhang wrote:
>> Hi,
>>
>> Is it possible to link native codes generated by different compiler?
>>
>> the usecase could be:
>> Linux kernel compiled by gcc want to load kernel module compiled by
Clang
>> (I know there have some problem to compile kernel by Clang currently,
>> but ignore those problem in here)
>>
>> I just concern about the call conversion problem, and compatibility
>> between gcc and clang.
>
> Hi Jovi,
> It can be complicated. Many distributions patch gcc, the kernel, and the
> entire tool chain. A good example is RedHat, which applies many many
patches
> to the kernel and the tool chain, including gcc. I believe embedded
releases
> are similar. The canonical kernel releases are only tested on specific
canonical
> versions of gcc. While I am certain you can realize this goal, you might
run into
> some subtle problems. I would start by auditing the tool chains and kernels
you are
> using, to understand any changes they have made downstream from the
canonical kernel
> and gcc releases. In the case of RedHat, I believe they require you to
build the
> kernel with their tool chain. They will not support any modifications to
the build
> process or the kernel. So, in a situation such as you describe, you are
likely on
> your own.
>
Thanks Karen, your info is helpful for me.
I will check the tool chain firstly.