[LLVMdev] error: instruction requires: thumb2

[Eli Friedman]

On Thu, Aug 16, 2012 at 12:55 PM, Lei Zhao <leizhao833 at gmail.com> wrote:
> Hi Everybody,
>
>   I recently did a cross-compiling using clang (built with host=x86, target=arm) with the following command:
>
>   > clang -march=armv7-a -mfloat-abi=soft -ccc-host-triple arm-none-linux-gnueabi -integrated-as main.c -o main.o -c
>
> and get error message:
>
> -------------------------------------------------------
> main.c:9:9: error: instruction requires: thumb2
>         "ldrex %[oldValue], [%[ptr], #0]\n" // oldValue = *ptr
>         ^
> <inline asm>:1:2: note: instantiated into assembly here
>         ldrex r6, [r4, #0]
>         ^
> main.c:11:3: error: instruction requires: thumb2
>         "strexeq %[failed], %[newValue], [%[ptr], #0]\n"
>          ^
> <inline asm>:3:1: note: instantiated into assembly here
> strexeq r5, lr, [r4, #0]
> ^
> 2 errors generated.
> -------------------------------------------------------
>
>   In the main.c, some ARM assembly are embedded which contains instructions ldrex, strexeq. I don't know what the message suggests since the cpu specified does support thumb2. Could someone help? Thanks.

Try "-mthumb".

-Eli