Build shared lib on windows?

h-vetinari commented 1 year ago

This recently came up in #213, where I noted:

I see [@isuruf] added the =NO on windows in https://github.com/conda-forge/llvmdev-feedstock/commit/8059f3a076bfc1770ab993c22e882fc7279e66a3 (though I don't see relevant comments in the corresponding PR). That commit is also relevant because it introduced another point about this recipe I'm not 100% sure about - currently on windows, libllvm16 & llvm are completely empty packages - I presume because this would be for the shared libraries which we're not building currently.

I've also just stumbled across https://github.com/apache/arrow/pull/37412, which does

  if(MSVC)
    # It seems that conda's llvmdev for Windows doesn't provide shared
    # library.
    set(ARROW_LLVM_USE_SHARED_DEFAULT OFF)
  else()
    set(ARROW_LLVM_USE_SHARED_DEFAULT ${ARROW_DEPENDENCY_USE_SHARED})

Would appreciate your input @isuruf on whether we should do this at all, and what blockers (if any) you see.

isuruf commented 1 year ago

AFAIK, upstream LLVM does not support shared libraries on windows.

h-vetinari commented 1 year ago

Indeed:

LLVM_BUILD_LLVM_DYLIB:BOOL: [...] This option is not available on Windows.

conda-forge / llvmdev-feedstock

Build shared lib on windows? #237