On Tue, Mar 10, 2015 at 12:24:03PM +0000, Daniel P. Berrange wrote:
On Tue, Mar 10, 2015 at 01:05:22PM +0100, Ján Tomko wrote:
> On Mon, Mar 09, 2015 at 02:03:16PM +0100, Martin Kletzander wrote:
> > On Mon, Mar 09, 2015 at 10:09:17AM +0000, Daniel P. Berrange wrote:
> > >On Mon, Mar 09, 2015 at 11:01:31AM +0100, Martin Kletzander wrote:
> > >> On Thu, Mar 05, 2015 at 11:09:41AM +0000, Daniel P. Berrange wrote:
> > >> >On Thu, Mar 05, 2015 at 12:05:52PM +0100, Ján Tomko wrote:
> > >> >>Explicitly request that virNumaNodeIsAvailable not be inlined.
> > >> >>This fixes the test suite when building with clang (3.5.1).
> > >> >
> > >> >Huh, so clang will inline functions, even if they are exported
> > >> >in the .so library ? Is there some clang compiler flag we can
> > >> >use to stop that ? I'd only expect it to inline stuff which
> > >> >was declared static, or whose impl body was in the header file
> > >> >
> > >>
> > >> If I understand it correctly, that means that clang is not
> > >> "compatible" with gcc.
> > >>
> > >> Excerpt from gcc online docs [1]:
> > >>
> > >> When a function is both inline and static, if all calls to the
> > >> function are integrated into the caller, and the function's
address
> > >> is never used, then the function's own assembler code is never
> > >> referenced.
> > >>
> > >> Excerpt from gcc online docs [1]:
> > >>
> > >> By default, Clang builds C code in GNU C11 mode, so it uses standard
> > >> C99 semantics for the inline keyword. These semantics are different
> > >> from those in GNU C89 mode, which is the default mode in versions of
> > >> GCC prior to 5.0.
> > >>
> > >> However further reading of the second documentation and c89 semantics
> > >> it doesn't say anything about the fact that such function should
be
> > >> inlined.
> > >
> > >But we haven't added the 'inline' keyword to this function at
> > >all - it is just a normal function marked for export in the
> > >.so file, so I'm puzzelled why it is getting inlined.
> > >
> >
> > Exactly, that's what I'm trying to find out as well.
> >
> > >>
> > >> Anyway, is this clang 3.6 specific? I don't have this problem
when
> > >> compiling with 3.5. Nor does this show with gcc -std=gnu11. I'm
> > >> getting 3.6 to check whether that's the difference.
> > >>
> >
> > After updating clang and llvm from 3.5 to 3.6, I still don't get this
> > error. And I have only 4 (fake) nodes available, so it _is_ rewriting
> > that function.
>
> I'm getting the error with 3.5.1, as I said in the commit message.
>
I missed that, sorry.
> These are the failing qemuxml2argvtest cases:
> 60) QEMU XML-2-ARGV hugepages-pages
> ... libvirt: error : internal error: NUMA node 1 is unavailable
> 63) QEMU XML-2-ARGV hugepages-shared
> ... libvirt: error : internal error: NUMA node 1 is unavailable
> 324) QEMU XML-2-ARGV numatune-memnode
> ... libvirt: error : internal error: NUMA node 1 is unavailable
> 326) QEMU XML-2-ARGV numatune-memnode-no-memory
> ... libvirt: error : internal error: NUMA node 3 is unavailable
> 329) QEMU XML-2-ARGV numatune-auto-prefer
> ... libvirt: error : internal error: NUMA node 1 is unavailable
>
> So with 4 fake nodes, the tests could still pass even if the function is
> not mocked. Try changing the nodeset in #326 to 4 if it fails.
>
I tried changing that, it fails. I tried adjusting the tests to more
nodes, it fails. After adjusting the mock function again, it works.
So it gets mocked all the time, but I know where the difference is,
probably. Try building with -O0, it will probably disable the
inlining. However, if that's the case, I believe it's still clang's
fault since they don't document inlining functions without the
"inline" keyword just because you optimize.
> >
> > >> [1]
https://gcc.gnu.org/onlinedocs/gcc/Inline.html
> > >> [2]
http://clang.llvm.org/compatibility.html
> > >>
> > >> >>---
> > >> >>This only leaves the mysterious check-protocol failure.
> > >>
> > >> That's not that mysterious, it's just that we check the order
and
> > >> clang sorts enums before structs, but gcc doesn't. Also clang
adds
> > >> "public:" to structs, so it probably treats it as a C++ or C#
structs
> > >> or something?
> > >>
> >
> > By the way if I compile with clang with -std=gnu11 or -std=gnu99, the
> > "public:" stuff is gone :)
> >
>
> It is mysterious, because it doesn't fail consistently.
Oh, it does fail all the time for me.
> It was working for me after I tried it again after
> 'git clean -fxd', today it failed again (though I don't remember if I
> ran autogen again).
How exactly are you running the build with clang ? Are you just doing
this
CC=clang ./autogen.sh && make && make check
Or is there more to it than that ?
I have a script that does "export CC=clang" and then ./autogen.sh and
make (everything).