[PATCH] D64482: [Driver] Define _FILE_OFFSET_BITS=64 on Solaris

Thu Jul 11 04:28:49 PDT 2019

ro added a comment.

In D64482#1579850 <https://reviews.llvm.org/D64482#1579850>, @MaskRay wrote:

>

> Honestly I find such enforced C/C++ difference very unfortunate... e.g.
> 
>   if (Opts.CPlusPlus)
>     Builder.defineMacro("_GNU_SOURCE");

You may not like them, but there are plenty of examples in `OSTargets.h` (for kFreeBSD, Hurd, Linux, RTEMS, AIX, Windows, NaCl and
several more).  Why take offense in the Solaris case if this is already common practice?

> Solaris seems the only exception that defines these Large File Support extension macros on the compiler driver side. Isn't it possible to do it in a common system header file?

Even if it were, this would only affect future releases.  The user experience of "you need to upgrade to Solaris 11.x" or install update y
to get this" seems pretty dismal to me.  Besides, that ship has sailed and GCC 9 is released.

Apart from that, I strongly suspect that there are other reasons.  Large file support is only relevant for 32-bit targets.  However, many
OSes have switched to 64-bit only by now.  And testing non-default multilibs just doesn't happen in LLVM: I haven't found a way to do
so yet, while it's quite easy to run all gcc testsuites for a common set of multilibs.  Even building LLVM for Linux/i686 or Solaris/i386
proved to be highly problematic and not (regularly) tested.

> That rationale will be better than this paragraph in the description:
> 
>> make check-all currently fails on x86_64-pc-solaris2.11 when building with GCC 9:
> 
> With the current description, a casual reader (like I) would just think this patch is probably not doing things at the correct layer.

That description only served to show what problem as hand is being solved, not just an abstract desire for g++ compatibiliy.

Repository:
  rC Clang

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  https://reviews.llvm.org/D64482/new/

https://reviews.llvm.org/D64482