On 15 March 2017 at 19:45, Manuel Lauss wrote: > Hello, > > I'm trying to build a current mesa git shapshot with LTO, > and it fails with this error in src/compiler/: (gcc-6.3.1 as of > today, glibc-2.25) > > x86_64-pc-linux-gnu-g++ -m32 -fvisibility=hidden -Werror=pointer-arith > -Werror=vla -O3 -march=haswell -mtune=haswell-flto=9 > -fno-fat-lto-objects -pipe -Wall -fno-math-errno -fno-trapping-math > -Wl,-O1 -o glsl_compiler glsl/main.o -Wl,--as-needed > glsl/.libs/libstandalone.a -lz -lpthread > /usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/32/libstdc++.so: undefined > reference to `pthread_create' > /usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/32/libstdc++.so: undefined > reference to `pthread_once' > /usr/lib/gcc/x86_64-pc-linux-gnu/6.3.0/32/libstdc++.so: undefined > reference to `pthread_join' > > Any ideas why pthread_once() can't be found? /lib32/libpthread.so does > have all the above mentioned symbols. Without LTO, it builds just fine > (however performance of the library suffers, lto helps mesa a lot). Does it help if you put -Wl,--no-as-needed before -lpthread? The weak symbols in libstdc++.so might make the linker think it doesn't need the real ones from libpthread.so
