[PATCH] D25324: [ELF] - Check that section alignment is a power of 2.

[Rafael Espíndola via llvm-commits]

LGTM since the spec says "Currently, only 0 and positive integral
powers of two are allowed". But instead of

> -  if (Header->sh_addralign > UINT32_MAX)
> -    fatal(getFilename(File) + ": section sh_addralign is too large");
> +  if (Header->sh_addralign > UINT32_MAX ||
> +      (Header->sh_addralign && !isPowerOf2_32(Header->sh_addralign)))
> +    fatal(getFilename(File) + ": section sh_addralign is invalid");
>    Alignment = std::max<uintX_t>(Header->sh_addralign, 1);

I think it is simpler to write

uintX_t V =  std::max<uintX_t>(Header->sh_addralign, 1);
if (V >  UINT32_MAX || !isPowerOf2_32(V))
  fatal
Alignment = V;

Cheers,
Rafael