Re: [PATCH] ld - Add SYMBOL_ABI_ALIGNMENT variable and apply to __bss_start

[Nick Clifton <nickc@redhat.com>]

Hi Andreas,

> Currently not specific alignment is applied to the __bss_start
> symbol. However, on s390x we require every symbol to be on an even
> address.  The patch introduces a new variable for the elf.sc template
> which allows to specify such an symbol alignment requirement.

This patch looks good, but I see one issue - there are lot more symbols
provided by the elf.sc template than just __bss_start.  So if an ABI
requires symbols to be aligned, then that should apply to all symbols,
right ?

Actually there is one other thing.  Rather than doing:

    ${RELOCATING+. = ALIGN(${SYMBOL_ABI_ALIGNMENT});}
    ${RELOCATING+${CREATE_SHLIB+PROVIDE (}${USER_LABEL_PREFIX}__bss_start = .${CREATE_SHLIB+)};}

Wouldn't it make more sense to do:

    ${RELOCATING+${CREATE_SHLIB+PROVIDE (}${USER_LABEL_PREFIX}__bss_start = ALIGN (.${CREATE_SHLIB+), ${SYMBOL_ABI_ALIGNMENT});}

Ie making it clear that the alignment is being applied to the symbol.

It might even be possible to create a macro to do all of this
USER_LABEL_PREFIX and ALIGN munging, so that it does not have
to be repeated countless times in the elf.sc file.  I have not
actually checked to see if this is possible, but it would be
nice if it could be done.

Cheers
   Nick