llvm-project

e321d2a1 - [CMake] Re-enable LIBCXX_HARDENING_MODE for assert build (#182383)

[CMake] Re-enable LIBCXX_HARDENING_MODE for assert build (#182383) Previously in #68541, the change disabled LIBCXX_HARDENING_MODE for all non-bootstrapping assert build to fix bootstrapping issues. CMake variable `LIBCXX_HARDENING_MODE` is only affective in libcxx build to set a default harderning mode. That means unless the build is bootstrapped from the newly built libcxx, the harderning mode is not enabled for assert built compiler, thus the compiler loses test coverage like accessing the value from an empty std::optional. The fix is to correctly define `_LIBCPP_HARDENING_MODE` in a way that respect user defined LIBCXX_HARDENING_MODE. To be extra safe, compile and test the defined marco will not cause error before using it.