Re: Link with mixed IR/non-IR objects

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Apr 27, 2011 at 8:06 AM, Markus Trippelsdorf
<markus@trippelsdorf.de> wrote:
> On 2011.04.27 at 07:38 -0700, H.J. Lu wrote:
>> On Wed, Apr 27, 2011 at 7:29 AM, Markus Trippelsdorf
>> <markus@trippelsdorf.de> wrote:
>> > On 2011.04.27 at 06:49 -0700, H.J. wrote:
>> >> Here is a proposal to link with mixed IR/non-IR objects:
>> >>
>> >> * 2 kinds of object files
>> >> ? o non-IR object file has
>> >> ? ? * non-IR sections
>> >> ? o IR object file has
>> >> ? ? * IR sections
>> >> ? ? * non-IR sections
>> >> ? ? * The output of "ld -r" with mixed IR/non-IR objects should work
>> >> with:
>> >> ? ? ? ? o Compilers/linkers with IR support.
>> >> ? ? ? o Compilers/linkers without IR support.
>> >> * Add the mixed object file which has
>> >> ? o IR sections
>> >> ? o non-IR sections:
>> >> ? ? * Object codes from IR sections.
>> >> ? ? * Object codes from non-IR object files.
>> >> ? o Object-only section:
>> >> ? ? * With section name ".gnu_object_only" and SHT_GNU_OBJECT_ONLY
>> >> type
>> >> ? ? on ELF:
>> >> ? ? #define SHT_GNU_OBJECT_ONLY 0x6ffffff8 ? ?/* Object only */
>> >
>> > I'm wondering if it wouldn't be better to simply use:
>> > SHT_GNU_IRBITS (= 0x6fff4952)
>> > that has already been proposed here:
>> > http://gcc.gnu.org/wiki/whopr/driver ?
>> >
>> > »Thus, we plan to mark the IR sections with a special section type,
>> > SHT_GNU_IRBITS (= 0x6fff4952).«
>> >
>>
>> They are different. SHT_GNU_OBJECT_ONLY section doesn't contain
>> any IR. It encapsulates a relocatable object file without any IR bits.
>
> Of course. What I was trying to ask was if SHT_GNU_IRBITS and
> SHT_GNU_OBJECT_ONLY aren't exactly complementary to each other?

They are independent of each other.

> (IOW, if SHT_GNU_IRBITS would be implemented, would there still be a
> need for SHT_GNU_OBJECT_ONLY?)

We sill need SHT_GNU_OBJECT_ONLY to support mixing IR/non-IR
object files.

-- 
H.J.