[LLVMdev] Using the unused "version" field in the bitcode wrapper (redux)

[Herbie Robinson]

On 11/4/14 5:57 PM, Chris Lattner wrote:
> On Nov 4, 2014, at 7:04 AM, Robinson, Paul <Paul_Robinson at playstation.sony.com> wrote:
>
>>> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of Sean Silva
>>>
>>> You haven't established that you really need this. AFAIK Apple's linker
>>> doesn't need this version information and they have shipped LTO for a
>>> while now.
>> Does Apple support library/middleware providers shipping bitcode instead
>> of object code?
> No.
>
> -Chris
>
It would be practically impossible without some versioning scheme to 
ensure the old toolchains reject newer (as in new enough to be 
incompatible) bitcode. Also, the mechanism would have to be pretty 
obvious; so, things like installers can check easily.