[LLVMdev] why doesn't LLVM link its dependencies dynamically?

[Yale Zhang]

The build times only apply for the libraries, opt, and lli. I've disabled
the rest, so if you're building everything, the time saved should be more.

On Tue, Oct 7, 2008 at 1:46 PM, Yale Zhang <yzhang1985 at gmail.com> wrote:

> OK. I've tried using shared libraries for everything except LLVMX86.o, and
> the build time improvement isn't as good as I hoped for. On a Dell Precision
> 390 workstation, the time to rebuild after a one line change in a library is
> 10 s for static linking and 7.3 s for dynamic linking (building in Eclipse
> is slower).
>
> One advantage of static linking I haven't thought about is that only the
> needed functions need to be loaded, unlike everything for dynamic libraries.
> The space saving is huge though: 1350MiB vs 723MiB and the IO load is
> probably greatly reduced.
>
> I've added a hackish script that patches LLVM 2.3 to use dynamic libraries
> if anyone wants it. Just run it after configuring.
>
>
> On Tue, Oct 7, 2008 at 10:50 AM, Gordon Henriksen <gordonhenriksen at me.com>wrote:
>
>> On Oct 6, 2008, at 15:52, Yale Zhang wrote:
>>
>> > Hi everyone. I'm mainly build the debug versions of lli and opt
>> > which are huge and take up to 10 seconds to build. It seems there is
>> > no option in configure to allow dynamic linking. Before I try to add
>> > it myself, is there a reason why it's not done?
>>
>> In addition to the APIs being insufficiently stable for shared
>> libraries to be of much use per se, it invoked pathologically bad
>> performance in some dynamic link editors--startup times greatly
>> exceeding your link times.
>>
>> — Gordon
>>
>>
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>
>
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