Build flags: Difference between revisions
imported>Appetrosyan Moved to templates and fixed rendering. |
imported>Symphorien mention stdenv.hostPlatform.*support |
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nix-build optimised_openssl.nix --option system-features gccarch-skylake | nix-build optimised_openssl.nix --option system-features gccarch-skylake | ||
</code> | </code> | ||
==== Adapting a derivation to specific plaforms ==== | |||
The technique above should pass the correct flags to gcc so that it uses the processor to its fullest. However, some build systems or configure scripts want to know whether to enable some processor-specific instructions, for example sse. One way to do so is to inspect the <code>stdenv.hostPlatform.*Support</code> predicates: here is an example from g2o: | |||
<code> | |||
cmakeFlags = [ "-DDISABLE_SSE3=${ if stdenv.hostPlatform.sse3Support then "OFF" else "ON"}" ] | |||
</code> | |||
Available flags are defined in [https://github.com/NixOS/nixpkgs/blob/master/lib/systems/architectures.nix lib/systems/architectures.nix]. | |||
==== Building the whole system on NixOS ==== | ==== Building the whole system on NixOS ==== | ||