This repo contains CoreRT, an experimental .NET Core runtime optimized for AOT (ahead of time compilation) scenarios, with the accompanying compiler toolchain.
Android on ARM64 doesn't follow the recommended way how to implement Thread Local Storage (TLS). Instead they are using a custom solution when a __thread variable is used. This solution requires that internally always a C function needs to be called when a TLS variable is access. While the compiler and linker take care of all the c/c++ code the helper code written in assembler needs to be modified.
This implements the changes for the current thread and thunks data TLS variable. It would work on systems that follow the recommended implementation, too. But as it has a larger overhead compared to the current inlined solution it needs to be activated for systems with this issue by using FEATURE_EMULATED_TLS
jkotas
commented
3 years ago
Android on ARM64 doesn't follow the recommended way how to implement Thread Local Storage (TLS). Instead they are using a custom solution when a __thread variable is used. This solution requires that internally always a C function needs to be called when a TLS variable is access. While the compiler and linker take care of all the c/c++ code the helper code written in assembler needs to be modified.
This implements the changes for the current thread and thunks data TLS variable. It would work on systems that follow the recommended implementation, too. But as it has a larger overhead compared to the current inlined solution it needs to be activated for systems with this issue by using FEATURE_EMULATED_TLS