Host Clang must be able to find libstdc++4.7 or newer

[FrancescoTerrosi]

Hi, i'm compiling a software that internally builds llvm with this script (starts at line 40, fails at line 59)

As you can see, the console output complains about the version of my libstdc++ (which i'm pretty sure it's 6 and not lower than 4.7) and looking at CmakeError.log it says that the program fails when including (second log)

I ran this same script on other computers and things work just fine, any help would be appreciated,

Thank you

Console output

CMake Deprecation Warning at CMakeLists.txt:20 (cmake_policy):
The OLD behavior for policy CMP0051 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.

-- The C compiler identification is Clang 3.9.1
-- The CXX compiler identification is Clang 3.9.1
-- The ASM compiler identification is Clang
-- Found assembler: /usr/bin/clang-3.9
-- Check for working C compiler: /usr/bin/clang-3.9
-- Check for working C compiler: /usr/bin/clang-3.9 -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/clang++-3.9
-- Check for working CXX compiler: /usr/bin/clang++-3.9 -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test LLVM_NO_OLD_LIBSTDCXX
-- Performing Test LLVM_NO_OLD_LIBSTDCXX - Failed
CMake Error at cmake/modules/CheckCompilerVersion.cmake:38 (message):
Host Clang must be able to find libstdc++4.7 or newer!
Call Stack (most recent call first):
cmake/config-ix.cmake:14 (include)
CMakeLists.txt:465 (include)

-- Configuring incomplete, errors occurred!
See also "Build/llvm-build/CMakeFiles/CMakeOutput.log".
See also "Util/Build/llvm-build/CMakeFiles/CMakeError.log".`

============================================================================

CMakeError.log

Checking whether the ASM compiler is GNU using "--version" did not match "(GNU assembler)|(GCC)|(Free Software Foundation)":
clang version 3.9.1-19ubuntu1 (tags/RELEASE_391/rc2)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Performing C++ SOURCE FILE Test LLVM_NO_OLD_LIBSTDCXX failed with the following output:
Change Dir: Util/Build/llvm-build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_3ae75/fast
/usr/bin/make -f CMakeFiles/cmTC_3ae75.dir/build.make CMakeFiles/cmTC_3ae75.dir/build
make[1]: Entering directory 'Util/Build/llvm-build/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_3ae75.dir/src.cxx.o
/usr/bin/clang++-3.9 -DLLVM_NO_OLD_LIBSTDCXX -std=c++0x -o CMakeFiles/cmTC_3ae75.dir/src.cxx.o -c Util/Build/llvm-build/CMakeFiles/CMakeTmp/src.cxx
Util/Build/llvm-build/CMakeFiles/CMakeTmp/src.cxx:2:10: fatal error: 'atomic' file not found
#include
^
1 error generated.
CMakeFiles/cmTC_3ae75.dir/build.make:65: recipe for target 'CMakeFiles/cmTC_3ae75.dir/src.cxx.o' failed
make[1]: *** [CMakeFiles/cmTC_3ae75.dir/src.cxx.o] Error 1
make[1]: Leaving directory 'Util/Build/llvm-build/CMakeFiles/CMakeTmp'
Makefile:121: recipe for target 'cmTC_3ae75/fast' failed
make: *** [cmTC_3ae75/fast] Error 2

Source file was:

#include
std::atomic x(0.0f);
int main() { return (float)x; }

[efriedma-quic]

The error message is complaining that your host compiler is broken (can't build C++ code that uses <atomic>). We can't provide support for clang 3.9.