[D-runtime] druntime should be a shared library/DLL

[Walter Bright]

On 3/5/2013 11:45 AM, Rainer Schuetze wrote:
> On 05.03.2013 16:35, Artur Skawina wrote:
>> On 03/01/13 18:38, Rainer Schuetze wrote:
>>> - What is happening on linux? I guess there is no import table there so 
>>> relocations are pointing directly into the shared library, but what about PC 
>>> relative adressing?
>>
>> http://www.iecc.com/linker/linker10.html
>>
>> artur
>>
>
> Thanks for the link. The article seems to be a bit old, though (1999, no 
> 64-bit, seems to compare to XP). Not sure how much has changed since.
>
> It isn't clear from the initial description, but the comparison at the end 
> gives me the impression that ELF allows direct data relocations into another 
> shared library very much like what I've tried to implement for Windows.
>
> I've tried generating some ELF object files (under windows by compiling for 
> TARGET_LINUX), but I don't see any code generated to support 64-bit data 
> addresses. How is this going to work?

My understanding is the ELF 64 bit ABI does not allow more than 32 bits worth of 
code in an app, i.e. all the code (including shared libraries) will be within a 
32 bit offset of each other.

Also, I tend to answer similar questions by writing a bit of C code illustrating 
the issue, compiling it, and dumping the result. dumpobj and obj2asm were 
crafted for that purpose. It usually answers the question - I find the 
documentation contains too many errors, assumptions, and omissions to be reliable.