Barretenberg does not cross compile for Apple Mac builds based on toolchain selected

[kevaundray]

Problem

Mac's are able to cross compile from x86_64 to arm64. So if you are running an x86, you can cross compile to arm and vice versa. This is useful for the CI where arm builds are in beta.

Our current toolchain files, however do not set the appropriate flags to allow us to cross compile, this means that even if you select the aarch64 toolchain, you will be compiling for x86_64 if your Mac is x86_64.

Solution

Set the appropriate flags to the compiler when the toolchain is set. For arm it is:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -arch arm64") set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -arch arm64")

Note

The fact that the arm build was building for x86_64 was spotted by @kobyhallx