Le 31/10/2019 à 22:51, Samuel Thibault a écrit :
Source: llvm-toolchain-8
Version: 1:8.0.1-3
Severity: serious
Justification: FTBFS
Hello,
Since the migration of gcc-defaults to gcc-9, llvm-toolchain-8 FTBFS,
with
CMake Error at tools/polly/lib/External/CMakeLists.txt:91 (message):
No ffs implementation found
looking at CMakeError.log, one actually see:
Source file was:
int main() { (void)__builtin_ffs(0); return 0; }
Performing C SOURCE FILE Test HAVE_DECL__BITSCANFORWARD failed with the following output:
Change Dir: /build/llvm-toolchain-8-8.0.1/build-llvm/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make" "cmTC_11f2c/fast"
make[2]: Entering directory
'/build/llvm-toolchain-8-8.0.1/build-llvm/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_11f2c.dir/build.make
CMakeFiles/cmTC_11f2c.dir/build
make[3]: Entering directory
'/build/llvm-toolchain-8-8.0.1/build-llvm/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_11f2c.dir/src.c.o
/usr/bin/gcc-9 -D_GNU_SOURCE -g -O2
-fdebug-prefix-map=/build/llvm-toolchain-8-8.0.1=. -fstack-protector-strong
-Wformat -Werror=format-security -fPIC -Werror=date-time -Wall -Wextra
-Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -pedantic
-Wno-long-long -Wimplicit-fallthrough -Wno-comment -ffunction-sections
-fdata-sections -flto=thin -DHAVE_DECL__BITSCANFORWARD -o
CMakeFiles/cmTC_11f2c.dir/src.c.o -c
/build/llvm-toolchain-8-8.0.1/build-llvm/CMakeFiles/CMakeTmp/src.c
cc1: error: unrecognized argument to '-flto=' option: 'thin'
i.e. llvm passed -flto=thin to gcc-9, which does not understand it.
gcc-8 used to understand it, but not gcc-9 any more. I had to comment in
debian/rules CMAKE_EXTRA += -DLLVM_ENABLE_LTO="Thin" to get it built.
Samuel
Indeed, this is why I am forcing the build of -9 with gcc-8 for now :)
See https://bugs.llvm.org/show_bug.cgi?id=43193 for more info!
S
