[PATCH v2 2/5] powerpc/boot: Fix crt0.S syntax for clang

[Nick Desaulniers]

On Thu, Sep 13, 2018 at 9:07 PM Joel Stanley <joel at jms.id.au> wrote:
>
> Clang's assembler does not like the syntax of the cmpdi:
>
>  arch/powerpc/boot/crt0.S:168:22: error: unexpected modifier on variable reference
>          cmpdi   12,RELACOUNT at l
>                               ^
>  arch/powerpc/boot/crt0.S:168:11: error: unknown operand
>          cmpdi   12,RELACOUNT at l
>                    ^
> Enclosing RELACOUNT in () makes it is happy. Tested with GCC 8 and Clang
> 8 (trunk).
>
> Reported to clang as https://bugs.llvm.org/show_bug.cgi?id=38945
>
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
> v2: Fix for !powerpc64 too, add bug link to commit message
> ---
>  arch/powerpc/boot/crt0.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S
> index dcf2f15e6797..e453e011d7e7 100644
> --- a/arch/powerpc/boot/crt0.S
> +++ b/arch/powerpc/boot/crt0.S
> @@ -80,7 +80,7 @@ p_base:       mflr    r10             /* r10 now points to runtime addr of p_base */
>         lwz     r9,4(r12)       /* get RELA pointer in r9 */
>         b       12f
>  11:    addis   r8,r8,(-RELACOUNT)@ha
> -       cmpwi   r8,RELACOUNT at l
> +       cmpwi   r8,(RELACOUNT)@l
>         bne     12f
>         lwz     r0,4(r12)       /* get RELACOUNT value in r0 */
>  12:    addi    r12,r12,8
> @@ -165,7 +165,7 @@ p_base:     mflr    r10             /* r10 now points to runtime addr of p_base */
>         ld      r13,8(r11)       /* get RELA pointer in r13 */
>         b       11f
>  10:    addis   r12,r12,(-RELACOUNT)@ha
> -       cmpdi   r12,RELACOUNT at l
> +       cmpdi   r12,(RELACOUNT)@l

Yep, as we can see above, when RELACOUNT is negated, it's wrapped in
parens.  It's important for Clang's assembler to match GAS eventually,
but for now, this change simply cononicalizes all of the the
references to RELACOUNT in this source file.
Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>

>         bne     11f
>         ld      r8,8(r11)       /* get RELACOUNT value in r8 */
>  11:    addi    r11,r11,16
> --
> 2.17.1
>


-- 
Thanks,
~Nick Desaulniers