Re: [PATCH v2 1/3] tests/tcg: Make the QEMU headers available to the tests

[Thomas Huth <thuth@redhat.com>]

On 24/04/2023 15.10, Ilya Leoshkevich wrote:
> On Mon, 2023-04-24 at 14:00 +0100, Alex Bennée wrote:
>>
>> Ilya Leoshkevich <iii@linux.ibm.com> writes:
>>
>>> The QEMU headers contain macros and functions that are useful in
>>> the
>>> test context. Add them to tests' include path. Also provide a
>>> header
>>> similar to "qemu/osdep.h" for use in the freestanding environment.
>>>
>>> Tests that include <sys/auxv.h> get QEMU's copy of <elf.h>, which
>>> does
>>> not work without <stdint.h>. Make use of the new header in these
>>> tests
>>> in order to fix this.
>>>
>>> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>>> ---
>>>   tests/include/qemu/testdep.h   | 14 ++++++++++++++
>>>   tests/tcg/Makefile.target      |  4 ++--
>>>   tests/tcg/aarch64/sve-ioctls.c |  1 +
>>>   tests/tcg/aarch64/sysregs.c    |  1 +
>>>   4 files changed, 18 insertions(+), 2 deletions(-)
>>>   create mode 100644 tests/include/qemu/testdep.h
>>>
>>> diff --git a/tests/include/qemu/testdep.h
>>> b/tests/include/qemu/testdep.h
>>> new file mode 100644
>>> index 00000000000..ddf7c543bf4
>>> --- /dev/null
>>> +++ b/tests/include/qemu/testdep.h
>>> @@ -0,0 +1,14 @@
>>> +/*
>>> + * Common dependencies for QEMU tests.
>>> + *
>>> + * SPDX-License-Identifier: GPL-2.0-or-later
>>> + */
>>> +#ifndef QEMU_TESTDEP_H
>>> +#define QEMU_TESTDEP_H
>>> +
>>> +#include <stdint.h>
>>> +#include "qemu/compiler.h"
>>> +
>>> +#define g_assert_not_reached __builtin_trap
>>> +
>>> +#endif
>>> diff --git a/tests/tcg/Makefile.target b/tests/tcg/Makefile.target
>>> index 8318caf9247..5474395e693 100644
>>> --- a/tests/tcg/Makefile.target
>>> +++ b/tests/tcg/Makefile.target
>>> @@ -85,8 +85,8 @@ TESTS=
>>>   # additional tests which may re-use existing binaries
>>>   EXTRA_TESTS=
>>>   
>>> -# Start with a blank slate, the build targets get to add stuff
>>> first
>>> -CFLAGS=
>>> +# Start with the minimal build flags, the build targets will
>>> extend them
>>> +CFLAGS=-I$(SRC_PATH)/include -I$(SRC_PATH)/tests/include
>>>   LDFLAGS=
>>
>> Hmm I'm not so sure about this. The tests are deliberately minimal in
>> terms of their dependencies because its hard enough getting a plain
>> cross-compiler to work. Is there really much benefit to allowing
>> this?
>> What happens when a user includes another header which relies on
>> functionality from one of the many libraries QEMU itself links to?
> 
> I don't think this will work at all, because the idea here is to allow
> using the code in the freestanding tests. However, at least bswap.h
> seems to work just fine. Of course, there is now additional maintenance
> overhead to keep it this way, but I would argue it's better than
> making a copy.

If this is just about one single header, I guess a

#include "../../../include/qemu/bswap.h"

would be acceptable, too, instead?

  Thomas