&gt; There are LLVM targets with corresponding ABIs that are nonspecific to architectures like PNaCL but Apple is not using them<p>They <i>do indeed</i> support LLVM IR target(s) that are, in fact, much more architecturally-nonspecific than PNaCl, namely the
    spir[64]-unknown-unknown
target. See <a href="https:&#x2F;&#x2F;github.com&#x2F;KhronosGroup&#x2F;SPIR" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;KhronosGroup&#x2F;SPIR</a> and &#x2F;System&#x2F;Library&#x2F;Frameworks&#x2F;OpenCL.framework&#x2F;Versions&#x2F;A&#x2F;Libraries&#x2F;openclc (on a Mac, since 10.7).<p>I don&#x27;t know if bitcode with this target triple is necessarily suitable for the Apple Watch, however.