Re: [PATCH 1/4] Initial support for GNU_PROPERTY_1_NEEDED

[Florian Weimer <fweimer@redhat.com>]

* H. J. Lu via Libc-alpha:

> diff --git a/elf/elf.h b/elf/elf.h
> index 2a62b98d4a..45b107fdcf 100644
> --- a/elf/elf.h
> +++ b/elf/elf.h
> @@ -1310,6 +1310,23 @@ typedef struct
>  /* No copy relocation on protected data symbol.  */
>  #define GNU_PROPERTY_NO_COPY_ON_PROTECTED	2
>  
> +/* A 4-byte unsigned integer property: A bit is set if it is set in all
> +   relocatable inputs.  */
> +#define GNU_PROPERTY_UINT32_AND_LO	0xb0000000
> +#define GNU_PROPERTY_UINT32_AND_HI	0xb0007fff
> +
> +/* A 4-byte unsigned integer property: A bit is set if it is set in any
> +   relocatable inputs.  */
> +#define GNU_PROPERTY_UINT32_OR_LO	0xb0008000
> +#define GNU_PROPERTY_UINT32_OR_HI	0xb000ffff
> +
> +/* The needed properties by the object file.  */
> +#define GNU_PROPERTY_1_NEEDED		GNU_PROPERTY_UINT32_OR_LO
> +
> +/* Set if the object file requires canonical function pointers and
> +   cannot be used with copy relocation.  */
> +#define GNU_PROPERTY_1_NEEDED_SINGLE_GLOBAL_DEFINITION	(1U << 0)
> +
>  /* Processor-specific semantics, lo */
>  #define GNU_PROPERTY_LOPROC			0xc0000000
>  /* Processor-specific semantics, hi */

Please add a stable link to the full specification.

I think we need more bits: one bit to indicate the status (in this
patch), and another bit to indicate linker support for this feature.
And perhaps yet another to indicate incompatibility with this feature.

Thanks,
Florian