[cfe-dev] [llvm-dev] Why do we static link all llvm libraries in every executable?

[Craig, Ben via cfe-dev]

Properly separating global / default symbols from internal / hidden 
symbols would take a substantial amount of effort.  To put the amount of 
effort in perspective, there are more than 700 LLVM headers that provide 
the interface between the LLVM static libraries.  There are more than 
300 Clang headers to provide the interface between the Clang static 
libraries.

I think the change could be done, and it would be valuable, but it isn't 
a quick change.  You would also get to deal with all the non-portable 
platform peculiarities.

On 1/26/2016 3:32 PM, Yin Ma via cfe-dev wrote:
>
> Hi,
>
> Thank you for explaining and providing the option. I will give a try.
>
> 10x slower..on Linux? If we limit the number of global symbols 
> exposed, it will
>
> help the situation?
>
> Yin
>
> *From:*llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of 
> *David Blaikie via llvm-dev
> *Sent:* Tuesday, January 26, 2016 7:46 AM
> *To:* Yury Gribov
> *Cc:* llvm-dev; Clang Dev
> *Subject:* Re: [llvm-dev] [cfe-dev] Why do we static link all llvm 
> libraries in every executable?
>
> On Tue, Jan 26, 2016 at 12:44 AM, Yury Gribov via cfe-dev 
> <cfe-dev at lists.llvm.org <mailto:cfe-dev at lists.llvm.org>> wrote:
>
>     On 01/25/2016 09:16 PM, Joerg Sonnenberger via llvm-dev wrote:
>
>         On Mon, Jan 25, 2016 at 10:13:35AM -0800, Yin Ma via llvm-dev
>         wrote:
>
>             If we separate several shared libraries something like
>             libclang.so, libllvm.so and let all executables and
>             llvmgold.so just
>             linked with .so. A lot of space could be saved and
>             loading performance could be improved.
>
>
>         There is a build option to do exactly that. It comes at a
>         significant
>         price for startup, e.g. clang will take 10x as long for
>         building a small
>         example.
>
>
>     Is this to process runtime relocations or run constructors? I
>     wonder if Prelink or ElfHack could help.
>
> Runtime relocations, I would imagine (global ctors would have to run 
> in either mode - so shouldn't represent a difference, I would think?)
>
>         Joerg
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