Re: [PATCH 1/5] arm: LLVMLinux: Add current_stack_pointer macrofor ARM

[Russell King - ARM Linux]

On Fri, Sep 06, 2013 at 05:28:07PM -0400, behanw@xxxxxxxxxxxxxxxxxx wrote:
> From: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx>
> 
> A macro to get the current stack pointer which allows for a single place in
> which to do so with ASM. Before this named registers (a gcc extension) was used
> to get the stack pointer. Using ASM is a more portable way of getting the stack
> pointer which works with both gcc and clang.  This macro is of the same name
> used in the X86 arch.

This will result in less optimal code - rather than the compiler being
able to mask directly with 'sp', it's going to have to use this bit of
assembly to first move it into another register.

Why do we want this change?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/