LLVM/Clang cross-compiling for ARM

[Vassilis Laganakos]

Hi Damjan, Mark,

----- Original Message -----

> From:Damjan Marion <damjan.marion at gmail.com>
> To:Mark Tinguely <marktinguely at gmail.com>
> Cc:Vassilis Laganakos <vassilis.laganakos at yahoo.com>; "freebsd-arm at freebsd.org" <freebsd-arm at freebsd.org>
> Sent:Thursday, April 14, 2011 8:13 AM
> Subject:Re: LLVM/Clang cross-compiling for ARM
> 
> 
> Hi Mark,
> 
> Seems that clang from current (made by i386 buildworld) is able to build ARM 
> code:
> 
> # clang -v                                                                      
>                                                                                 
>     FreeBSD clang version 2.9 (trunk 126547) 20110226
> Target: i386-undermydesk-freebsd9.0
> Thread model: posix
> 
That's the same I get when I build llvm/clang as a cross-compiler, and I thought that
something was wrong. I'd expect that to be: "arm-unknown-freebsd9.0", but it
seems from your test bellow that it does generate ARM code.

> # clang -march=armv7-a -mfloat-abi=soft -ccc-host-triple arm-elf -integrated-as 
> hello.c -o hello.o -c                                                            
>                   
> # file hello.o                                                                  
>                                                                                 
>   
> hello.o: ELF 32-bit LSB relocatable, ARM, version 1 (SYSV), not stripped
> 
> # clang -march=armv7-a -mfloat-abi=soft -ccc-host-triple arm-elf hello.c -o 
> hello.S -S
> 
> # cat hello.S
> 
>     .syntax unified
>     .cpu cortex-a8
>     .eabi_attribute 6, 10
>     .eabi_attribute 7, 65
>     .eabi_attribute 8, 1
>     .eabi_attribute 9, 2
>     .eabi_attribute 10, 2
>     .eabi_attribute 20, 1
>     .eabi_attribute 21, 1
>     .eabi_attribute 23, 3
>     .eabi_attribute 24, 1
>     .eabi_attribute 25, 1
>     .file    "hello.c"
>     .text
>     .globl    main
>     .align    2
>     .type    main,%function
> main:
>     push    {r11, lr}
>     mov    r11, sp
>     sub    sp, sp, #12
>     mov    r0, #0
>     str    r0, [r11, #-4]
>     str    r0, [sp, #4]
>     movw    r0, :lower16:.L.str
>     movt    r0, :upper16:.L.str
>     bl    printf
>     str    r0, [sp]
>     ldr    r0, [sp, #4]
>     mov    sp, r11
>     ldmia    sp!, {r11, pc}
> .Ltmp0:
>     .size    main, .Ltmp0-main
> 
>     .type    .L.str,%object
>     .section    .rodata.str1.1,"aMS",%progbits,1
> .L.str:
>     .asciz     "Hello World!\n"
>     .size    .L.str, 14
>


Well you proved the opposite from what we assumed, since this looks like ARM assembly to me :)

Anyone knows if something has changed in http://wiki.freebsd.org/BuildingFreeBSDWithClang
since it was last edited?


Damjan, if you find some more info about this with llvm/clang, could you please post
the links here? :)

Thanks,
Vassilis