Re: Has anyone tried building for Windows?

[David Malcolm <dmalcolm@redhat.com>]

On Fri, 2015-07-31 at 00:14 -0700, Mukul Sabharwal wrote:
> For GCCSharp [https://github.com/mjsabby/GCCSharp], I did get GCC with
> the JIT frontend working* but with modifications. I've been wanting to
> tell Dave about them, so here is the very short list:

Thanks for posting this.

> (1) `fchmod` in playback::compile_to_file::copy_file isn't supported
> on MinGW - maybe put this behind an ifdef?

Perhaps that whole function could be replaced with a call to ::CopyFile
on Windows? (and ::GetLastError).

> (2) `dlopen` and dl* family of things in
> playback::context::dlopen_built_dso - again, on MinGW toolset this
> isn't available. Since this is not essential to the JIT API, maybe
> also make this something a user can opt out of?
> 
> So, the working* in my case was essentially generating .S files
> (GCC_JIT_OUTPUT_KIND_ASSEMBLER)

My Windows expertise is very rusty, but I believe something equivalent
could be cooked up using ::LoadLibrary, ::GetProcAddress,
and ::FreeLibrary.

(IIRC, Windows doesn't require the extension for the jit-generated
shared library to be ".dll"; I seem to remember in my past life as a
game developer working with plugins for apps that had other extensions).

> If there is an interest in having a LIBGCCJIT.DLL built with these
> modifications, I can certainly make a GitHub repo with some sort of
> binary and source drops.

I'm particularly interested in *how* you built it; a recipe would be
good to hear (I don't have a Windows development box handy, but maybe it
can run under Wine).

You mention "source drops" - note that for non-trivial changes, there
are some legal requirements that must be followed before I can commit
them back to the source tree; see:
https://gcc.gnu.org/contribute.html#legal
But if it's a case of simply #ifdef-ing a few lines out, that may be
below the threshold (I am not a lawyer).

Dave


> Mukul
> 
> 
> On Wed, Jul 29, 2015 at 12:51 PM, Dibyendu Majumdar
> <mobile@majumdar.org.uk> wrote:
> > On 29 July 2015 at 11:44, David Malcolm <dmalcolm@redhat.com> wrote:
> >> On Tue, 2015-07-28 at 22:43 -0700, Hayden Livingston wrote:
> >>> I've attempted to build on Windows using Cygwin and MingW-64 and I'm
> >>> not really familiar with the build system enough but I can't make any
> >>> forward progress.
> >>
> >> Thanks for trying this.  As far as I know, you're the first person who's
> >> attempted this.
> >>
> >
> > I tried a few days ago - but could not even get configure to work. It
> > kept complaining about missing mpfr, gmp, mpc even though these were
> > installed. I was using msys2 as the environment with mingw64
> > compilers. In the end decided life is too short and I have many other
> > things I need to do.
> >
> > Does gcc even compile on Windows without patches from mingw project?
> >
> > It is a pity as LLVM code generated on Windows has a serious
> > deficiency - longjmp calls cause crash as the generated code doesn't
> > conform to Windows requirements. I was hoping that gcc generated code
> > would not suffer from this.
> >
> > Regards
> > Dibyendu