[FFmpeg-devel] [PATCH] configure: add -fPIE instead of -pie to C flags for ThreadSanitizer

[Michael Niedermayer]

On Fri, Dec 02, 2016 at 02:04:53PM -0800, Wan-Teh Chang wrote:
> -pie was added to C flags for ThreadSanitizer in commit
> 19f251a2882a8d0779b432e63bf282e4d9c443bb. Under clang 3.8.0, the -pie
> flag causes a compiler warning and a linker error when running configure
> --toolchain=clang-tsan. Here is an excerpt from config.log:
> 
> clang ... -fsanitize=thread -pie -std=c11 -fomit-frame-pointer -pthread -c -o /tmp/ffconf.hL61stP9.o /tmp/ffconf.YO6ZaSFG.c
> clang: warning: argument unused during compilation: '-pie'
> clang -fsanitize=thread -pie -Wl,--as-needed -Wl,-z,noexecstack -o /tmp/ffconf.W5c2e41l /tmp/ffconf.hL61stP9.o -lbz2 -pthread
> /usr/bin/ld: /tmp/ffconf.hL61stP9.o: relocation R_X86_64_PC32 against undefined symbol `atan2f@@GLIBC_2.2.5' can not be used when making a shared object; recompile with -fPIC
> /usr/bin/ld: final link failed: Bad value
> clang: error: linker command failed with exit code 1 (use -v to see invocation)
> 
> To be conservative, I changed -pie to -fPIE. But the documentation seems
> to imply just -fsanitize=thread is enough:
> 
> http://clang.llvm.org/docs/ThreadSanitizer.html
> https://github.com/google/sanitizers/wiki/ThreadSanitizerCppManual
> 
> Signed-off-by: Wan-Teh Chang <wtc at google.com>
> ---
>  configure | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

applied

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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and strip your own citizens of their rights and freedoms. to be continued
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