Date: Mon, 7 Jan 2013 18:25:03 +0200 From: David Naylor <naylor.b.david@gmail.com> To: freebsd-toolchain@freebsd.org Cc: Nathan Whitehorn <nwhitehorn@freebsd.org>, freebsd-arch@freebsd.org Subject: Re: LLVM Image Activator Message-ID: <201301071825.06439.naylor.b.david@gmail.com> In-Reply-To: <50E9BC2D.7000302@freebsd.org> References: <50E9BC2D.7000302@freebsd.org>
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--nextPart1362420.XBIvH0nEZn Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi, Just my 2c On Sunday, 6 January 2013 20:02:21 Nathan Whitehorn wrote: > Having LLVM/clang in the base system lets us do some interesting things > that we couldn't do with GCC. One is that LLVM ships with a JIT for LLVM > IR as well as components of a toolchain for it (this is what Google's > pNACL uses) and that you can end up producing binary files that are in > IR instead of native code. The IR isn't really cross-platform, but does > let you do CPU-specific optimizations when executed by the JIT, etc. >=20 > The attached patch causes the LLVM JIT (lli) to be built by default > (adding ~20 seconds to buildworld on my five-year-old laptop) and adds a > kernel image activator that invokes it when passed LLVM bitcode files. > It's not completely finished (see the XXX comment in the middle), but it > does work, as follows: >=20 > $ clang -emit-llvm -c -o hw.ll hw.c > $ file hw.ll > hw.ll: LLVM bitcode > $ lli hw.ll > Hello world! > $ chmod a+x hw.ll > $ ./hw.ll > Hello world! > $ >=20 > Is there any interest in having features like this? It seems like this > could provides some interesting possibilities for us and nice > integration from having imported clang into base. Would it be possible to have this as a module (and thus in ports)? Or,=20 perhaps, change the sources such these things could be loaded as a module... Also, with modification to LLVM, wouldn't the existing '#!' mechanism work= =20 (aka '#!/usr/bin/lli') at the beginning of the file? =20 On an aside. Could you imagine shipping a 'x86' llvm-byte code and get the= =20 jit (with caching), thus your computer will get full support (speed) from t= he=20 binaries and the binaries will work on all 'x86' related architectures. (M= y=20 thinking is for things like i386 vs pentium4). =20 Regards --nextPart1362420.XBIvH0nEZn Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEABECAAYFAlDq9uIACgkQUaaFgP9pFrKo3ACeNX5ZhxuslKEem1bHkRpR8YQd HDoAn1Ukz4GTpxieoB7u1C7UFCSJsV90 =r9wK -----END PGP SIGNATURE----- --nextPart1362420.XBIvH0nEZn--
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