Problem compiling simple main.c with llvm-5.0

Clang Frontend Using Clang
1

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#changes-to-the-avr-target

so I'd expect this target is supported?

Thanks for any help.

2

Looks like AVR is experimental, so you’ll need to pass it via -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=“AVR”

3

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.