Date: Wed, 10 Jul 2019 12:28:56 -0600 From: Ian Lepore <ian@freebsd.org> To: adr <adr@SDF.ORG> Cc: freebsd-arm@freebsd.org Subject: Re: FreeBSD arm EABI5 documentation? Message-ID: <da6a8f7e596da9bf9015f76798a5575908ad1be4.camel@freebsd.org> In-Reply-To: <alpine.NEB.2.21.1907101735020.3201@sdf.lonestar.org> References: <alpine.NEB.2.21.1907101508370.22895@sdf.lonestar.org> <f2967859f68f1d40f260661791126956f48f4d12.camel@freebsd.org> <alpine.NEB.2.21.1907101735020.3201@sdf.lonestar.org>
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On Wed, 2019-07-10 at 18:19 +0000, adr wrote: > On Wed, 10 Jul 2019, Ian Lepore wrote: > > Stack alignment requirement is 8 bytes. The full EABI spec is > > here: > > > > https://static.docs.arm.com/ihi0042/g/aapcs32.pdf > > I suppose then that this behavior is not a OS imposition, but > the llvm calling convention. I'll search in their documentation. > I've never used clang before. > It is both a toolchain and an OS matter. The OS comes into play with things like syscalls and signal handling, where arg passing and stack alignment requirements have to be compatible between kernel and userland. Also, the toolchain and the OS are more tightly coupled in freebsd than you may be used to. Freebsd isn't a kernel with other stuff from other sources glommed on, it's the full combination of kernel and userland and toolchain and build system all integrated together into a single source base. The good news is that freebsd is in sync with pretty much the entire rest of the world in this regard. EABI (aka gnueabihf) is the standard used by all major OSes and toolchains these days for armv7. And clang is very gcc-compatible; if you have code that compiles with modern gcc, it should compile with no changes using clang; even command-line options and flags are compatible. -- Ian > > I can't help with the gcc thing, I've only used clang from base for > > compiling proprietary code. > > Well, deinstalling gcc fix the problem. I almost heard the soup nazi: > not gcc for you! > > Regards, > adr. > _______________________________________________ > freebsd-arm@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org > "
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