Re: [Qemu-devel] [PULL 00/21] tcg patch queue

[Peter Maydell]

On 19 October 2018 at 07:10, Richard Henderson
<address@hidden> wrote:
> On 10/18/18 3:34 AM, Peter Maydell wrote:
>> The win32 build fails with:
>>
>> target/arm/helper-a64.o: In function `helper_paired_cmpxchg64_le_parallel':
>> /home/petmay01/qemu-for-merges/target/arm/helper-a64.c:573: undefined
>> reference to `helper_atomic_cmpxchgo_le_mmu'
>> target/arm/helper-a64.o: In function `helper_paired_cmpxchg64_be_parallel':
>> /home/petmay01/qemu-for-merges/target/arm/helper-a64.c:647: undefined
>> reference to `helper_atomic_cmpxchgo_be_mmu'
>> target/arm/helper-a64.o: In function `helper_casp_le_parallel':
>> /home/petmay01/qemu-for-merges/target/arm/helper-a64.c:669: undefined
>> reference to `helper_atomic_cmpxchgo_le_mmu'
>> target/arm/helper-a64.o: In function `helper_casp_be_parallel':
>> /home/petmay01/qemu-for-merges/target/arm/helper-a64.c:690: undefined
>> reference to `helper_atomic_cmpxchgo_be_mmu'
>
> This one I could not reproduce.  Tested with i686-w64-mingw32-gcc
> and x86_64-w64-mingw32-gcc, both version 6.2.
>
> I suspect configure misfired.  If you can, start this one over with a blank
> build directory.

Something odd is going on here. My merge test when I merged your v2
passed (unless I managed to miss a failure message first time around
which isn't impossible). But on a subsequent test for a later merge,
I get the same error:

  LINK    aarch64-softmmu/qemu-system-aarch64w.exe
target/arm/helper-a64.o: In function `helper_paired_cmpxchg64_le_parallel':
/home/petmay01/qemu-for-merges/target/arm/helper-a64.c:573: undefined
reference to `helper_atomic_cmpxchgo_le_mmu'
target/arm/helper-a64.o: In function `helper_paired_cmpxchg64_be_parallel':
/home/petmay01/qemu-for-merges/target/arm/helper-a64.c:647: undefined
reference to `helper_atomic_cmpxchgo_be_mmu'
target/arm/helper-a64.o: In function `helper_casp_le_parallel':
/home/petmay01/qemu-for-merges/target/arm/helper-a64.c:669: undefined
reference to `helper_atomic_cmpxchgo_le_mmu'
target/arm/helper-a64.o: In function `helper_casp_be_parallel':
/home/petmay01/qemu-for-merges/target/arm/helper-a64.c:690: undefined
reference to `helper_atomic_cmpxchgo_be_mmu'
collect2: error: ld returned 1 exit status

I did a complete "blow away build/w32 entirely and
reconfigure" and the failure is still there.
config-host.mak defines neither CONFIG_ATOMIC128 nor CONFIG_CMPXCHG128,
which is what I'd expect for a w32 build. (The w64 build does
define CONFIG_ATOMIC128, and does build.)

Any idea what's going on here? tcg/tcg.h has a comment saying
 * The cmpxchg functions are only defined if HAVE_CMPXCHG128
so presumably the issue is that the helper-a64 code is
trying to refer to them anyway. There certainly doesn't
seem to be any kind of #defining around the listed functions
in helper-a64.c to stop them being compiled in this situation.

NB: I build with --enable-debug in this tree -- are you
perhaps accidentally relying on the compiler's optimisation
to discard these functions if they're not needed?

thanks
-- PMM