llvm dev - Jan 2016 - Problem with the way BUILD_SHARED_LIBS=ON handled in llvm 3.8

Hi,

For lllvm 3.7 and before BUILD_SHARED_LIBS=ON would produce versioned
shared libs like

libLLVMLTO.so (symlink)
libLLVMLTO.so.3.7 (symlink)
libLLVMLTO.so.3.7.0 (real file)

now it just builds an unversioned libLLVMLTO.so file which I believe
is a problem because when a program links to llvm it generates a
runtime dependency on libLLVMLTO.so instead of libLLVMLTO.so.3.7.0
which will break versioned dependencies.

Can we please get this behaviour back?

Thanks,
ismail

The LLVM libraries are not API stable (especially not the ones you generate with
BUILD_SHARED_LIBS). Those libraries are really not intended to ship. What are
you trying to accomplish? Have you tried using libLTO or libLLVM? The later is
generated with the option LLVM_BUILD_LLVM_DYLIB=On.

-Chris

> On Jan 18, 2016, at 3:25 AM, Ismail Donmez <ismail at i10z.com>
wrote:
> 
> Hi,
> 
> For lllvm 3.7 and before BUILD_SHARED_LIBS=ON would produce versioned
> shared libs like
> 
> libLLVMLTO.so (symlink)
> libLLVMLTO.so.3.7 (symlink)
> libLLVMLTO.so.3.7.0 (real file)
> 
> now it just builds an unversioned libLLVMLTO.so file which I believe
> is a problem because when a program links to llvm it generates a
> runtime dependency on libLLVMLTO.so instead of libLLVMLTO.so.3.7.0
> which will break versioned dependencies.
> 
> Can we please get this behaviour back?
> 
> Thanks,
> ismail

Hi,

On Tue, Jan 19, 2016 at 7:18 PM, Chris Bieneman <beanz at apple.com>
wrote:
> The LLVM libraries are not API stable (especially not the ones you generate
with BUILD_SHARED_LIBS). Those libraries are really not intended to ship.
I know that's why I need them versioned. Currently we (openSUSE) ship
libLLVM package which will install libLLVMFooBar.so.3.7 files and
llvm-devel package will ship unversioned libLLVMFooBar.so.

So, any application linking against LLVM generates a dependency
against the versioned libLLVMFooBar.so.3.7 and not against the
unversioned library. This way when we ship the new libLLVM 3.8 old
application will have to be recompiled to correctly link against the
new LLVM

LLVM 3.7 and before did this correctly and 3.8 should not break this.
As I said in another mail I tried -DLLVM_BUILD_LLVM_DYLIB=ON
-DLLVM_LINK_LLVM_DYLIB=ON but it's not currently usable as it is.

Thanks,
ismail