How do I call clang for AVR targets?

Clang Frontend
1

As an developer in the world of embedded control I'm playing around with Clang to see its capabilities. And since it is advertised as being usable for ARM and AVR (among a lot of other targets) I tried these.

Here at home I'm running Linux, but at the job I'm bound to use Windows. So I'm using Clang 5.0.0 installed by the provided Windows x64 installer. The AVR-GCC is the current WinAVR from 2010. (Yes, I'm aware that there are newer versions, but I have to use this one due to company policies.)

With the ARM target I had no problems; compiling with Clang and linking with GCC produced executables that ran fine in a simulator. I have no real machine at hand in the moment to check further.

But the AVR target gives me a hard time. Anything I tried leads to the error "unable to create target: 'No available targets are compatible with this triple.'"

There is a lot to read at the websites of Clang and LLVM, and I did read. But unfortunately I found nothing helpful.

Finally I tried to follow the source code but to no avail.

The command line is like
"clang -target avr -mmcu=atmega128 -I<path-to-winavr-includes> source.c"

These are the targets I tried:
avr
avr-unknown-unknown
avr-elf
avr-gcc

What command line is supposed to be given for a successful compilation?

2

Only these targets are built by default in cmake. AVR doesn’t appear to be one of them. So that probably means the release binaries don’t build it either. You can check what targets have been compiled in by using “llc --version”

List of all targets to be built by default:

set(LLVM_ALL_TARGETS
AArch64
AMDGPU
ARM
BPF
Hexagon
Lanai
Mips
MSP430
NVPTX
PowerPC
Sparc
SystemZ
X86
XCore
)

3

Thanks for the clarification. Clang 5.0.0 was kind of advertised like "Now with AVR!" and so I got curious.

Unfortunately lcc is not part of the installation via the Windows installer. Is there any other way to find out what triples are supported?

Cheers, Bodo

4

Unfortunately lcc is not part of the installation via the Windows installer.

Oops, I mean llc, of course. No offend!

Is there any other way to find out what triples are supported?

Just to push up this question in the list again: Is there any way for the humble user of the Windows installer to find out about accepted triples?

I feel this to be necessary to broaden the usage of Clang/LLVM among us plain vanilla developers. Usually there is no time to guess and try several combinations until one seems to work.

-Bodo