Re: [Qemu-devel] [PATCH 39/67] target: replace command line flags with preprocessor

[Eric Blake]

On 05/03/2018 02:51 PM, Michael S. Tsirkin wrote:
> Each target is currently built with a different set of include
> directories, this is what makes it possible to pull in a separate copy
> of header files depending on the target.
>
> Replace with per-target ifdefs which are easier to understand.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>   include/target-dir.h | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 63 insertions(+)
>   create mode 100644 include/target-dir.h

Ah, now we get to the file mentioned in a couple of previous patches.

> +#ifndef QEMU_TARGET_DIR_H
> +#define QEMU_TARGET_DIR_H
> +
> +#if defined(TARGET_ALPHA)
> +#define TARGET_DIR_PREFIX ../target/alpha
> +#elif defined(TARGET_ARM)
> +#define TARGET_DIR_PREFIX ../target/arm

> +#elif defined(TARGET_XTENSA)
> +#define TARGET_DIR_PREFIX ../target/xtensa
> +#else
> +#error "Target-specific directory include missing"
> +#endif
> +
> +#define TARGET_DIR_HASH(file) #file
> +#define TARGET_DIR_STRING(file) TARGET_DIR_HASH(file)
> +#define TARGET_DIR(file) TARGET_DIR_STRING(TARGET_DIR_PREFIX/file)

Cool trick!  It seems pretty reasonable to me.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org