Re: [avr-llvm-devel] AVR-LLVM on ARM?

[John M. <ato...@gm...>]

Hi Anton,

Great work!

What are your build steps? I believe clang should just pass unknown
arguments to GCC tools and -mmcu hasn't been added to avr-llvm (clang).
The target specific parts we had in were stripped out during the re-write
of the back-end. It hasn't been added back in yet, but it wasn't complete
anyways. But now that I've read your link I suppose you're not worried that
much about the back-end.

I don't know much about Arduino but this should help with understanding the
different folders (avr/avr-3/avr-4) and -mmcu.
http://www.nongnu.org/avr-libc/user-manual/using_tools.html

avr-gcc defines these macros based on -mmcu which then allows avr-libc
(io.h) to pick the correct header files.


On Wed, Dec 11, 2013 at 2:13 AM, Anton Smirnov <de...@an...>wrote:

> Hello.
>
> I was able to compile LLVM+Clang for ARM.
> Now i'm trying to use it as toolchain for Arduino and regular llvm build
> does not understand "-mmcu" argument.
>
> You can read my topic on Arduino forum:
> http://forum.arduino.cc/index.php?topic=203704.0
>
> What should be done to add avr support to llvm/clang?
>
> Regards, Anton.
>
>
> 2013/10/7 John Myers <ato...@gm...>
>
>>
>> I can't get cmake+ninja to even create the makefile. It says that the c++
>> compiler is broken (unable to compile a simple program), both with clang
>> and gcc.
>>
>> I tried using configure and gcc which will create the makefile if I
>> remove the -Wcovered-switch-default switch. But the build fails with a
>> bunch of undefined references when trying to link the FileCheck program.
>>
>> If I try with configure and clang I get a link error like yours were it
>> complains about the binary format for ELF not being correct.
>> I tried both with and without AVR as the target but it didn't seem to
>> change anything.
>>
>>
>> On Tue, Oct 1, 2013 at 1:44 PM, Anton Smirnov <de...@an...>wrote:
>>
>>> I have followed http://llvm.org/docs/HowToCrossCompileLLVM.htmlguide both on mac and linux but no luck.
>>> (I've also tried with -DLLVM_ENABLE_PIC=False as it seems to be the
>>> reason of "relocations in ELF" error on linux).
>>>
>>> Sure, i will be happy to get it finally when you have free time.
>>> It would be great to have  statically built libclang.so for ARM Linux and
>>> x86 Linux.
>>>
>>> Thanks a lot!
>>> Regards, Anton.
>>>
>>>
>>> 2013/10/2 John Myers <ato...@gm...>
>>>
>>>> Sure, I can try and compile it. I might not have time do to it until
>>>> tomorrow though.
>>>>
>>>>
>>>> Which configure options did you use?
>>>>
>>>>
>>>> On Mon, Sep 30, 2013 at 8:14 PM, Anton Smirnov <de...@an...>wrote:
>>>>
>>>>> Yes, i tried to build llvm + clang for ARM Linux and failed both on
>>>>> mac (ld does not support -version-script parameter error) and on linux
>>>>> (relocations in ELF error). I tried even with standalone toolchain from
>>>>> android ndk but i have another source issue (some functions not found). For
>>>>> host i succeed to compile but it's not what i need actually.
>>>>>
>>>>> Can you try to compile avr-llvm + clang for arm linux in your dev
>>>>> environment please?
>>>>>
>>>>> Regards, Anton.
>>>>>
>>>>>
>>>>>  2013/10/1 John Myers <ato...@gm...>
>>>>>
>>>>>> Hi Anton,
>>>>>>
>>>>>> I haven't tried yet, but I don't see any reason building for Android
>>>>>> wouldn't work. I've successfully built Windows binaries on Linux. I don't
>>>>>> thing there is anything AVR specific that would keep it from cross
>>>>>> compiling.
>>>>>>
>>>>>> There isn't a step-by-step for cross compiling avr-llvm. Once clang
>>>>>> and LLVM are patched with the AVR stuff the instructions for cross
>>>>>> compiling should be the same as it would be for the regular clang/LLVM.
>>>>>>
>>>>>> I don't have a Mac to test with. It could be a Mac specific issue.
>>>>>> Have you tried building the android binaries on a Linux host?
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 30, 2013 at 12:06 AM, Anton Smirnov <
>>>>>> de...@an...> wrote:
>>>>>>
>>>>>>> Hello.
>>>>>>>
>>>>>>> Can avr-llvm be hosted on ARM or x86 Linux device (Android to be
>>>>>>> more detailed)?
>>>>>>> Is there any step-by-step guide for cross-compilation on darwin or
>>>>>>> linux machine?
>>>>>>> (i've tried to cross-compile original llvm/clang on mac for arm
>>>>>>> linux and there is are a lot of unexpected problems)
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Anton.
>>>>>>>
>>>>>>>
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>>>>>>
>>>>>
>>>>
>>>
>>
>