Llvm5.0-devel May 2026

The answer is simple:

When compiling your tool against llvm5.0-devel , force the old ABI: llvm5.0-devel

In the fast-paced world of compilers, LLVM 18 and 19 are currently making headlines. So, why on earth would anyone write a blog post about llvm5.0-devel in 2026? The answer is simple: When compiling your tool

If you are linking a tool against llvm5.0-devel , always use LLVM_STATIC = ON in your CMakeLists, or prepare for missing libLTO.so errors. The C++ ABI Landmine LLVM 5.0 was compiled with GCC 5.1 or GCC 6 (depending on the distro). This uses the CXXABI_1.3.9 (Itanium ABI with C++11 features). If your modern system uses GCC 11+ (CXXABI_1.3.13), you may experience std::string ABI incompatibilities. The C++ ABI Landmine LLVM 5

llvm5.0-devel allows you to keep that legacy analysis pass alive without rewriting it for modern LLVM. You won't find this in apt default repos for Ubuntu 22.04+. You need specific EPEL or Legacy repos. On RHEL 7 / CentOS 7 (EPEL): sudo yum install epel-release sudo yum install llvm5.0-devel # Installs to: /usr/lib64/llvm5.0/ On Ubuntu 18.04 (Bionic) - Old repos: sudo apt install llvm-5.0-dev On Modern Systems (Manual Install): You likely need to build from source or use a Docker container: