[Qemu-devel] acpi tcg test errors when compiled with clang

["Marc Marí" <marc.mari.barcelo@gmail.com>]

While I was searching for other errors in make check, I set up a few
machines on top of virtualbox to compile and check qemu master, and
make check failed in a few of them when compiling with clang (< 3.5)
(gcc works perfectly). I found two errors in acpi/tcg test in
tests/bios-tables-test.c

--- Error 1 ---
Log (sometimes the first, sometimes the second):
/i386/acpi/tcg: [I 1421766735.433486] OPENED
{"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 2},
"package": ""}, "capabilities": []}}{"execute": "qmp_capabilities"}
{"return": {}}[R +0.027951] readb 0x7c10
[S +0.028104] OK 0x0000000000000000
[R +0.028267] readb 0x7c11
[S +0.028290] OK 0x0000000000000000
Broken pipe

/i386/acpi/tcg: [I 1421766738.230861] OPENED
{"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 2},
"package": ""}, "capabilities": []}}{"execute": "qmp_capabilities"}
{"return": {}}Broken pipe

Platforms it failed (all on top of Virtualbox):
 - Ubuntu 14.04.1 Linux 3.13.0 i386 Clang 3.4. Had to configure with
   -disable-werror because of "clang: error: argument unused during
   compilation: '-nopie'".

--- Error 2 ---
Log:
/i386/acpi/tcg: [I 1421845839.538638] OPENED
{"QMP": {"version": {"qemu": {"micro": 50, "minor": 2, "major": 2},
"package": ""}, "capabilities": []}}{"execute": "qmp_capabilities"}
{"return": {}}[R +0.025626] readb 0x7c10 [S +0.025858] OK
0x0000000000000000 [R +0.026287] readb 0x7c11
[S +0.026506] OK 0x0000000000000000
/home/markmb/qemu/cpu-exec.c:550:&: Object 0xb84dc1a0 is not an
instance of type 8�@�x�@�h\x04@�h\x04@�

Platforms it failed (all on top of Virtualbox):
 - Debian 7.8.0 Linux 3.2.0 i386 Clang 3.0-6
 - Ubuntu 12.04 Linux 3.13.0 i386 Clang 3.0-6

I tried in other setups with Clang 3.5 and no errors. I tried with
x86_64 virtualized systems and no errors. I tried in a native x86_64
(host for all tests. Debian 7 Linux 3.2.65 clang 3.0-6) and did not
fail. I could not test in a native i386.

Maybe it's not important as it just happens with old clangs, or maybe
you want to give it a look.

Thanks
Marc