Re: [PATCH 1/3] ArmPkg RVCT: add ADRL/LDRL macro equivalents

[Leif Lindholm <leif.lindholm@linaro.org>]

On Fri, Oct 28, 2016 at 12:42:52PM +0100, Ard Biesheuvel wrote:
> The GCC ARM builds have access to ADRL/LDRL macros that emit relative
> symbol references, i.e., references that do not require fixing up at
> load time (or FV generation time for XIP modules)
> 
> Implement equivalent functionality for RVCT: note that this does not
> use movw/movt pairs, but the more compatible add/add/add or add/add/ldr
> sequences (which Clang does not support, unfortunately, hence the use
> of movw/movt for the GCC toolchain family)
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Not tested, but looks sensible.
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

> ---
>  ArmPkg/Include/AsmMacroIoLib.inc | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/ArmPkg/Include/AsmMacroIoLib.inc b/ArmPkg/Include/AsmMacroIoLib.inc
> index c9cad5230c94..4bc3146fb399 100644
> --- a/ArmPkg/Include/AsmMacroIoLib.inc
> +++ b/ArmPkg/Include/AsmMacroIoLib.inc
> @@ -26,4 +26,24 @@
>    ldr  $Reg, =($Data)
>    MEND
>  
> +  MACRO
> +  adrll   $Reg, $Symbol
> +  add     $Reg, pc, #-8
> +  RELOC   R_ARM_ALU_PC_G0_NC, $Symbol
> +  add     $Reg, $Reg, #-4
> +  RELOC   R_ARM_ALU_PC_G1_NC, $Symbol
> +  add     $Reg, $Reg, #0
> +  RELOC   R_ARM_ALU_PC_G2, $Symbol
> +  MEND
> +
> +  MACRO
> +  ldrl    $Reg, $Symbol
> +  add     $Reg, pc, #-8
> +  RELOC   R_ARM_ALU_PC_G0_NC, $Symbol
> +  add     $Reg, $Reg, #-4
> +  RELOC   R_ARM_ALU_PC_G1_NC, $Symbol
> +  ldr     $Reg, [$Reg, #0]
> +  RELOC   R_ARM_LDR_PC_G2, $Symbol
> +  MEND
> +
>    END
> -- 
> 2.7.4
>