[cfe-dev] Does clang 3.8 support __aeabi_memclr4?

[Saleem Abdulrasool]

On Thu, Aug 6, 2015 at 9:50 AM, Fürst Stefan <dieb.stefan.96 at gmail.com>
wrote:

> Hello,
>
> i am trying to cross compile a nexus5 kernel with clang but at the end i
> get one error.
> The steps i did were
> git clone http://git.linuxfoundation.org/llvmlinux.git
> cd llvmlinux
> cd targets/vexpress
> make kernel-shell-for-build
> cd ../../
> cd targets
> cd nexus5
> make
>
> Than i applied all necessary patches.
> The build command looks like this
> make ARCH=arm
> CROSS_COMPILE=/home/stefan/llvmlinux/arch/arm/toolchain/linaro/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux/bin/arm-linux-gnueabihf-
> -l4 -j5
> GCC_TOOLCHAIN=/home/stefan/llvmlinux/arch/arm/toolchain/linaro/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux
> KBUILD_OUTPUT=/home/stefan/llvmlinux/targets/nexus5/build/kernel-clang
> HOSTCC="/home/stefan/llvmlinux/toolchain/clang/head/install/bin/clang"
> CC="/home/stefan/llvmlinux/toolchain/clang/head/install/bin/clang "
>
>
> drivers/built-in.o: In function `__video_do_ioctl':
> /home/stefan/llvmlinux/targets/nexus5/src/android_kernel_nexus5/drivers/media/video/v4l2-ioctl.c:1604:
> undefined reference to `__aeabi_memclr4'
> make[1]: *** [.tmp_vmlinux1] Error 1
> make: *** [sub-make] Error 2
>
> So does clang already support aeabi. Why does it fail?
>

The issue isn't clang.  It properly generated code for a hosted AEABI
compliant environment.  In fact, the error is indicating the problem: you
don't have an implementation for __aeabi_memclr4.  Where does the
implementation come from?  Since you are building a kernel, you are in a
freestanding environment, and the functionality that is normally provided
by the C runtime (libc) is not present.   You need to provide an
implementation yourself.


> Kind regards
> Stefan
>
>
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> cfe-dev at lists.llvm.org
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>
>


-- 
Saleem Abdulrasool
compnerd (at) compnerd (dot) org
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