[cfe-users] Problem compiling simple main.c with llvm-5.0

[Georg-Johann Lay via cfe-users]

On 28.12.2017 20:31, Don Hinton wrote:
> Looks like AVR is experimental, so you'll need to pass it via
> -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="AVR"
> 
> As for the correct --target, you can take a look at the logic in
> llvm/cmake/config.guess to get an idea on how to construct one.
> 
> hth...
> don

Ok, thanks for your information.

As it didn't appear to work, I just returned to GCC for now.

Thanks for your help.


> 
> On Wed, Dec 13, 2017 at 2:15 AM, via cfe-users <cfe-users at lists.llvm.org>
> wrote:
> 
>> Hi, I am new to llvm, so my first question is if this is the right
>> mailing list to address respective problems using that software.
>>
>> I downloaded the llvm 5.0.0 binary bundle, and I can compile simple
>> main.c for x64_64 host.  However, when
>>
>> .../bin/clang main.c --target=avr
>> error: unable to create target: 'No available targets are compatible with
>> this triple.'
>> 1 error generated.
>>
>> As --help is not much help, I tried guessing around using targets
>> elf32-avr, avr-unknown-none, all giving the same, unspecific diagnostic
>> (so much for "extremely useful error and warning messages").
>>
>> https://clang.llvm.org/docs/CrossCompilation.html
>>
>> claims:
>>
>>> On the other hand, Clang/LLVM is natively a cross-compiler, meaning
>>> that one set of programs can compile to all targets by setting the
>>> -target option.
>>
>> I checked the v5.0 sources, there are plenty of modules dealing with
>> AVR, so that target should be supported. No?
>>
>> So I downloaded the llvm 5.0.0 source bundle and configured for AVR:
>>
>> $ cmake -G "Unix Makefiles" -DLLVM_TARGETS_TO_BUILD="AVR"
>> ../../source/llvm-5.0.0.src/
>>
>> But:
>>
>> -- Constructing LLVMBuild project information
>> CMake Error at CMakeLists.txt:688 (message):
>>    The target `AVR' does not exist.
>>
>>        It should be one of
>>
>>
>> AArch64;AMDGPU;ARM;BPF;Hexagon;Lanai;Mips;MSP430;NVPTX;
>> PowerPC;Sparc;SystemZ;X86;XCore
>>
>> -- Configuring incomplete, errors occurred!
>> See also ".../build/llvm-5-avr/CMakeFiles/CMakeOutput.log".
>> See also ".../build/llvm-5-avr/CMakeFiles/CMakeError.log".
>>
>> The 5.0.0 release notes have some mention of AVR
>>
>> http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html#change
>> s-to-the-avr-target
>>
>> so I'd expect this target is supported?
>>
>> Thanks for any help.
>>
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>