El 02/07/18 a las 19:17, Carl Eugen Hoyos escribió:
2018-07-02 23:48 GMT+02:00, Gonzalo Garramuño <[email protected]>:
I would like to compile a version of the libav* libraries with tsan
knowledge. The configure script seems to have gcc-tsan as one toolchain
option. However that does not work for me, failing the compilation
test. My configure line is:
./configure --enable-gpl \
--toolchain=gcc-tsan \
I suggest you start with only "--toolchain-gcc-tsan" to debug.
Are you sure your default compiler supports tsan? I just
tested with vanilla gcc-6.4 and it works as expected.
Yes, I am using it to debug other code.
--enable-shared \
--enable-pic \
Why are you using this option?
Is there a bug in FFmpeg we don't know about?
I have other code that is compiled with -fPIC and mixing them is not
allowed afaik. Also, I want to have a shared debugging ffmpeg as much
as possible. I am currently running into what I believe are false
positives of tsan, but cannot tell for sure if there is no info in the
libav* libraries, so anything to get the line numbers and function names
is good.
--enable-runtime-cpudetect \
You don't need this option.
Glad to know.
The ffbuild/config.log reports at the end:
test_ld cc
test_cc
BEGIN /tmp/ffconf.AKKqustf/test.c
1 int main(void){ return 0; }
END /tmp/ffconf.AKKqustf/test.c
gcc -fsanitize=thread -fPIE -fPIC -c -o /tmp/ffconf.AKKqustf/test.o
/tmp/ffconf.AKKqustf/test.c
gcc -fsanitize=thread -pie -fPIC -o /tmp/ffconf.AKKqustf/test
/tmp/ffconf.AKKqustf/test.o
FATAL: ThreadSanitizer: unexpected memory mapping
0x55ebd936b000-0x55ebd936c000
C compiler test failed.
You apparently found this bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67308
Yes, it is exactly that bug! Removing -fPIE from the configure script
solves it for me. I have progressed further.
Thank you, Carl.
--
Gonzalo Garramuño
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