Re: [PATCH] Check for POSIX_MADV_WILLNEED to support building against the LSB

[Mark Kettenis <mark.kettenis@xs4all.nl>]

> Date: Mon, 11 Jun 2012 16:25:22 +1200
> From: Michael Hope <michael.hope@linaro.org>
> 
> The Linux Standard Base APIs include posix_madvise() but don't define
> values for the 'advice' argument.  Check to see if POSIX_MADV_WILLNEED
> is defined before using.

What real-world problem does this fix?  It makes no sense to have
posix_madvise() but not define any values for the 'advice' argument.
I'd say this is a "bug" in LSB.  Either they should drop
posix_madvise() from the standard, or include at least the 'advice'
values required by POSIX.

> 2012-06-11  Michael Hope  <michael.hope@linaro.org>
> 
> 	* dwarf2read.c (dwarf2_read_section): Check for
> 	POSIX_MADV_WILLNEED.
> 
> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 589361e..91fab5a 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -1773,7 +1773,7 @@ dwarf2_read_section (struct objfile *objfile, struct dwarf2_section_info *info)
> 
>         if ((caddr_t)info->buffer != MAP_FAILED)
>          {
> -#if HAVE_POSIX_MADVISE
> +#if HAVE_POSIX_MADVISE && defined(POSIX_MADV_WILLNEED)
>            posix_madvise (info->map_addr, info->map_len, POSIX_MADV_WILLNEED);
>   #endif
>            return;
>