[LLVMdev] proposal to avoid zlib dependency.

[Óscar Fuentes]

Reid Kleckner <rnk at google.com> writes:

> On Tue, Sep 16, 2014 at 7:47 PM, Óscar Fuentes <ofv at wanadoo.es> wrote:
>
>> IIUC zlib availability is tested and the library used if present. Do you
>> mean that LLVM does not use zlib on Windows when the library is present?
>
>
> Sure, but if there aren't instructions for how to do it easily, then it's
> effectively unsupported. There isn't really a canonical way to "install"
> headers and libraries on Windows like you would on Linux.

That's a non-issue. Downloading, compiling and installing zlib on
Windows takes about 10 minutes, for both MinGW and MSVC. There are
pre-compiled packages around too.

It is a good thing that LLVM works when zlib is not present, but
assuming that LLVM will not support certain zlib-related features
"because it is Windows" just shows how much misinformation some people
have about that OS.

> It probably works on MinGW, but then you're a MinGW binary in a MinGW
> world.

I think you are confusing MinGW with Cygwin. There is nothing special
about MinGW binaries. Moreover, for C code the libraries are compatible.
I've been using the same zlib binary on both MinGW(-w64) and MSVC for a
decade, across multiple toolset releases.

The "MinGW world" vs the "VS world" is restricted to C++, where
different ABIs are used by their respective compilers. That's nothing
new on Windows, which doesn't has a "platform C++ ABI" (nor Linux has,
because C++ has no special role on neither OS.) C++ compilers with
incompatible C++ ABIs are common on Windows. Actually, a MSVC++ version
is often incompatible with other versions.