Re: [PATCH 08/11] stubs/notify-event: Mark qemu_notify_event() stub as "weak"

[Thomas Huth]

On 04/08/2020 19.50, Richard Henderson wrote:
> On 8/4/20 10:00 AM, Thomas Huth wrote:
>> Otherwise there is a linker error with MinGW while compiling the tests:
>>
>>   LINK    tests/test-timed-average.exe
>>  libqemuutil.a(main-loop.o): In function `qemu_notify_event':
>>  /builds/huth/qemu/util/main-loop.c:139: multiple definition of
>>   `qemu_notify_event'
>>  
>> tests/test-timed-average.o:/builds/huth/qemu/tests/../stubs/notify-event.c:5:
>>   first defined here
>>  collect2: error: ld returned 1 exit status
>>  /builds/huth/qemu/rules.mak:124: recipe for target
>>   'tests/test-timed-average.exe' failed
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>  stubs/notify-event.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> That doesn't make sense.  Since the symbol is satisfied from main-loop.c, it
> should not be pulled in from libqemuutil.a.
> 
> What's really happening here?

Honestly, I don't have a clue. But since commit ebedb37c8d2aa4775, both
the code from util/ and from stubs/ are put into the same library,
libqemuutil.a, which is causing the trouble here, I guess.
Maybe the linker pulled in the code from the stub first, then some other
part used another function from  util/main-loop.c which caused the
linker to pull in main-loop.o, too, so that it finally found that there
is a clash? ... but that's just a plain guess, of course. Paolo (as
author of commit ebedb37c8d2), do you have an idea what might be going
on here?

 Thomas