fails to build on ARM

[svillemot]

As part of the maintenance of the Debian package for Julia, I tried to build Julia on Debian armel (ARM with soft-float). This first requires USE_SYSTEM_LIBM=1, and also the removal of GCC flag -momit-frame-leaf-pointer in Make.inc.

Then I get this error during LLVM compilation:

(test -f /home/sebastien/julia/usr/lib/arm-linux-gnueabi/julia/sys.ji || /home/sebastien/julia/usr/bin/julia-release-readline -bf sysimg.jl) && /home/sebastien/julia/usr/bin/julia-release-readline -f sysimg.jl || echo "Note: this error is usually fixed by running 'make cleanall'."
 LLVM ERROR: Not supported instr: BMOVPCRX_CALL %R3<kill>, %R0<kill>, %R1<kill>, %R2<kill>, <regmask>, %LR<imp-def,dead>, %SP<imp-use>, %SP<imp-def>, %R0<imp-def>; dbg:no file:0

Note that I am using LLVM 3.1 shipped by Debian sid.

The machine on which I am trying to compile is a Raspberry Pi. I can open shell accounts if this helps.

[ViralBShah]

@JeffBezanson suggests trying to build with LLVM_ASSERTIONS=1, and see what happens.

[ViralBShah]

Does it build fine on ppc now?

[JeffBezanson]

LLVM might not support all ARM flavors.

[svillemot]

I upgraded the Debian package to LLVM 3.2, I still get the same error (see https://buildd.debian.org/status/fetch.php?pkg=julia&arch=armhf&ver=0.0.0%2B20130107.gitd9656f41-2&stamp=1358613466 )

@JeffBezanson clang is available and can compile example C files, so LLVM supports my ARM machine
@ViralBShah on PPC it segfaults at the LLVM compile step (see https://buildd.debian.org/status/fetch.php?pkg=julia&arch=powerpc&ver=0.0.0%2B20130107.gitd9656f41-2&stamp=1358613382 )

I am currently recompiling LLVM with assertions enabled (it is taking a lot of time on my Raspberry Pi), I will give you more feedback when this is done.

[ViralBShah]

We probably need to figure out where the segfault is on ppc, in building the system image.

[nolta]

Apparently LLVM's jit is still broken on ppc64:

$ cd deps/llvm-3.2/build/examples/
$ make
$ cd HowToUseJIT/Release/
$ g++ `../../../Release/bin/llvm-config --ldflags` -o HowToUseJIT HowToUseJIT.o  `../../../Release/bin/llvm-config --libs`
$ ./HowToUseJIT 
We just constructed this LLVM module:

; ModuleID = 'test'

define i32 @add1(i32 %AnArg) {
EntryBlock:
  %0 = add i32 1, %AnArg
  ret i32 %0
}

define i32 @foo() {
EntryBlock:
  %0 = tail call i32 @add1(i32 10)
  ret i32 %0
}


Running foo: Segmentation fault (core dumped)

[svillemot]

This particular example works on my ARM machine. So I guess the PPC and ARM issues are different. I suggest that in this thread we focus on the ARM case. The PPC case seems anyways out of our control, since it is an LLVM bug.

[svillemot]

Rebuilding LLVM with assertions enabled does not help. I still get the same error message.

[ViralBShah]

flisp tests now segfault on armel:

https://buildd.debian.org/status/fetch.php?pkg=julia&arch=armel&ver=0.1%7E20130211.git86fbe98d-1&stamp=1360553590

[ViralBShah]

Discussion in #3134 on the same topic can continue in there. Closing this older one as a dup.

[ViralBShah]

Please follow progress in #7662.

[ViralBShah]

@sebastien-villemot We now have master building on ARM for armv7 and better. Perhaps not worth enabling on debian until we get all tests to pass first. I guess if we get it all done by 0.4, we can enable the ARM builds on debian buildd again.

[svillemot]

@ViralBShah Sure, I will try to enable ARM support as soon as Julia 0.4 is out.

For information, Debian currently has 3 ARM architectures:

• armel: ARMv4, 32-bit, no FPU (software emulation)
• armhf: ARMv7, 32-bit, with FPU
• arm64: ARMv8, 64-bit (AArch64 ABI)

Clearly armel is not a target for Julia. But armhf and arm64 are clearly candidates.