svn commit: r222183 - head/lib/clang
Roman Divacky
rdivacky at freebsd.org
Sun May 22 20:22:58 UTC 2011
The problem here is deeper in my opinion. What FreeBSD calls
amd64 the rest of the world (ie. linux) calls x86_64, I think
that instead of this we should teach llvm/clang about "amd64".
Maybe as a FreeBSD-only diff.
The machine part of the triple is used in more places and this
hack only is not the complete solution imho.
On Sun, May 22, 2011 at 04:32:45PM +0000, Dimitry Andric wrote:
> Author: dim
> Date: Sun May 22 16:32:44 2011
> New Revision: 222183
> URL: http://svn.freebsd.org/changeset/base/222183
>
> Log:
> On amd64, change clang's default triple to 'x86_64-unknown-freebsd9.0',
> similar to what we do for binutils. When clang's default triple starts
> with 'amd64-', it does not pass a proper -target-cpu option to its
> first stage.
>
> This can lead to problems, for example when structs are memcpy'd, and
> clang erroneously assumes they are 16-byte aligned. It will then use
> the 'movaps' SSE instruction to implement the copy, which results in a
> bus error if the struct is really 8-byte aligned.
>
> I encountered this issue when gcc's /usr/libexec/cc1 started crashing
> with SIGBUS, after rebuilding world with clang ToT, but it also affects
> the version of clang that we have in the tree. We were just lucky until
> now, apparently. :)
>
> Modified:
> head/lib/clang/clang.build.mk
>
> Modified: head/lib/clang/clang.build.mk
> ==============================================================================
> --- head/lib/clang/clang.build.mk Sun May 22 15:24:56 2011 (r222182)
> +++ head/lib/clang/clang.build.mk Sun May 22 16:32:44 2011 (r222183)
> @@ -15,7 +15,7 @@ CFLAGS+= -O1
>
> TARGET_ARCH?= ${MACHINE_ARCH}
> # XXX: 8.0, to keep __FreeBSD_cc_version happy
> -CFLAGS+=-DLLVM_HOSTTRIPLE=\"${TARGET_ARCH}-undermydesk-freebsd9.0\"
> +CFLAGS+=-DLLVM_HOSTTRIPLE=\"${TARGET_ARCH:C/amd64/x86_64/}-unknown-freebsd9.0\"
>
> .ifndef LLVM_REQUIRES_EH
> CXXFLAGS+=-fno-exceptions
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