mirror of
https://github.com/llvm/llvm-project.git
synced 2025-04-24 22:56:06 +00:00
b32aac4358
AArch64 GCS (Guarded Control Stack) is similar enough to CET that we can re-use the existing code that is guarded by _LIBUNWIND_USE_CET, so long as we also add defines to locate the GCS stack and pop the entries from it. We also need the jumpto function to exit using br instead of ret, to prevent it from popping the GCS stack. GCS support is enabled using the LIBUNWIND_ENABLE_GCS cmake option. This enables -mbranch-protection=standard, which enables GCS. For the places we need to use GCS instructions we use the target attribute, as there's not a command-line option to enable a specific architecture extension.